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Geberl, Cornelia. "Spatial and temporal resolution of bat sonar." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-160582.
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Davies, Amy. "Imaging of platelet actin nodule with high spatial and temporal resolution." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5173/.
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Platelets play a critical role in haemostasis and through platelet adhesion and aggregation ensure the integrity of the cardiovascular system is maintained in the event of an injury. The actin cytoskeleton plays a pivotal role their function. However, little is known about the role of a recently characterised actin structure, the actin nodule. The aims of this thesis are to characterise the actin nodule and elucidate their role in platelet spreading. To achieve this, platelets from the Lifeact-GFP transgenic mouse are used for live-cell imaging studies which demonstrate that actin nodules are a transient, surface-proximal, stationary actin structure which requires actin polymerisation downstream of SFK activity and the presence of Arp 2/3 complex. Additionally, their co-localisation with αIIb and results from previous work suggest a role for the actin nodule in platelet adhesion. The intracellular delivery of the actin label, Lifeact, and gold nanoparticles into human platelets using pH (low) insertion peptide is investigated and successful delivery of both represents a step forward in the ability to image actin dynamics in human platelets. Additionally, functionalisation of gold nanoparticles with multiple moieties including, a luminescent europium complex, demonstrate their potential as labels for multimodal imaging of human platelet actin nodule dynamics.
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Degbelo, Auriol [Verfasser], and Werner [Akademischer Betreuer] Kuhn. "Spatial and temporal resolution of sensor observations / Auriol Degbelo ; Betreuer: Werner Kuhn." Münster : Universitäts- und Landesbibliothek Münster, 2015. http://d-nb.info/1137626755/34.
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Geberl, Cornelia [Verfasser], and Lutz [Akademischer Betreuer] Wiegrebe. "Spatial and temporal resolution of bat sonar / Cornelia Geberl. Betreuer: Lutz Wiegrebe." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1041584563/34.
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Chen, Xiaolin. "Biological plant root growth detection from spatial and temporal resolution image sequences." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12039/.
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This thesis describes the development of a new approach to measuring the growth of plant roots. Work on changing the growth patterns of plants by the introduction of the right materials into their feed as well as the process of genetic manipulation is enhanced by being able to measure the growth of the plants roots in real time. Previous work in doing this has been subject to low reliability due in part to the nature of the problem. Plant root growth rates are of the order of 0.1 μm per second and thus have to be captured under the microscope. The plant surfaces show low contrast and have few predictable features so many methods prove to be inappropriate. Previous work in the measurement made use of the RootFlowRT software that uses a combination of a tensor based method and a correspondence method. However, the results from these methods have a high level of unreliability. The tensor method as applied shows a reliability of less than 10% and work carried out in this thesis shows that the correspondence method on its own cannot reliably predict the growth rates for large areas in any root. The work has introduced the use of Scale Space Optical Flow method to replace the previous tensor method and this has been shown to have a reliability of greater than 30% in almost all cases. The results of this method are then used to refine the search space for the correspondence method and again increase the reliability of the measurements. The validity of the final results using the current method are thus shown to be a great improvement on the previous method. For comparison: Percentage of measurements in the correct direction and size • RootFlowRT 70% • Current method 95% Maximum spread of invalid results • RootFlowRT +/-200% in size and 100% in direction • Current method +/-10% in size or direction
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Berry, Sam. "Ultra-high spatial and temporal resolution using Scanning Near-field Optical Microscopy." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/348102/.
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Scanning near-field optical microscopy (SNOM) is a system that can image beyond the conventional diffraction limit. It does this by collecting the information contained within evanescent fields. This unique ability to image using evanescent fields also enables SNOM to directly measure the electric field distribution in waveguides, where light is guided by total internal reflection. When SNOM is used with a spectrally resolving detector, local temporal phenomena can be detected by analysing spectral interference in the spectra collected by the probe. This spectrally resolving configuration was used to directly measure inter-modal group velocity difference in a multimode ridge waveguide and, using the modes’ spatial profiles to experimentally determine the mode amplitude coefficient ratio. Such an ability to provide measurements on the local dispersion characteristics and relative modal amplitudes of guided light establishes SNOM as a route for investigating the conversion of current single mode photonic devices into multimode devices. The spectrally resolving SNOM system was also used to investigate the sources of temporal delays created by a quasi disordered scattering sample, which was based on John H. Conway’s pinwheel tiling. Whilst the measurements do not create a complete picture of the scattering phenomena in this work, suggestions for improvement are offered with the aim establishing spectrally resolving SNOM systems as tools for mapping localised temporal phenomena in disordered scattering systems.
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Mokso, Rajmund. "Development and applications of coherent imaging with improved temporal and spatial resolution." Université Joseph Fourier (Grenoble), 2006. http://www.theses.fr/2006GRE10062.
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Les techniques d'imagerie sont ulitlisées, en science des matériaux, comme méthodes de caractérisation non destructives. Parmi ces techniques la tomographie au rayons X ouvre la voie à la caractérisation tridimensionelle. Les deux sujets principaux de cette thèse sont l'amélioration des résolution temporelle et spatiale de la tomographie aux rayons X. Ces deux aspects sont traités séparement. Dans la première partie, la description d'une nouvelle méthode de tomographie rapide et l'implementation aux mousses liquides est présentée. La deuxième partie est consacrée à l'étude d'une système optique pour la focalisation d'un faisceau de rayons X durs et son utilisation pour produire des images tomographiques avec une résolution spatiale de 290 nanomètres. Le travail a été réalisé à l'Installation Européenne de Rayonnement Synchrotron (ESRF) à GrenobleThis work had a twofold goal. Firstly to gain insight into the bulk of materials at a spatial resolution superior to what has been achieved so far for hard x-rays and secondly to improve the speed at which tomography can be performed. Ln the framework of this thesis an innovative acquisition scheme for fast tomographie imaging have been implemented, as weil as the first three-dimensional phase-contrast tomograrns has been acquired with a new focusing x-ray setup. The fast acquisition has been implemented to be able to perform the first extensive study of the coarsening behavior of liquid foams, whereas the magnified tomography has been applied to the study of aluminum alloys with a resolution of 290 nanomenters. The thesis has been prepared at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France
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Senay, Gabriel B. "Using High Spatial Resolution Spectral Data To Study Spatial and Temporal Variability in Corn and Soybean Management Systems /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487935125879758.
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Ristori, Pablo Roberto. "Development of a high spatial and temporal resolution Raman lidar for turbulent observations /." Lausanne : EPFL, 2008. http://library.epfl.ch/theses/?nr=3963.
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Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 3963 (2007), Faculté de l'environnement naturel, architectural et construit ENAC, Section des sciences et ingénierie de l'environnement, Institut des sciences et technologies de l'environnement ISTE (Laboratoire de pollution atmosphérique et du sol LPAS). Dir.: Hubert Van den Bergh.
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Sharp, Thomas Harry. "Biomolecular imaging at high spatial and temporal resolution in vitro and in vivo." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549684.
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This Thesis covers two separate projects linked by transmission electron microscopy (TEM) of biological samples: firstly, the utilisation of cryoTEM- TEM performed at cryogenic temperatures-to elucidate the superstructure of self-assembled peptide fibres, and secondly the development of new probes for Correlative Light Electron Microscopy (CLEM) both in vitro and in vivo. CryoTEM involves imaging samples in a hydrated state as close to experienced in bulk solvent as possible. This yields images and data that reflect the native state, and different to those of negatively stained samples that have been dried down and stained. Self-assembling peptide fibres (SAFs) were developed in the Woolfson lab in 2000 and characterised as α-helical coiled coils that grow both longitudinally and laterally. To date, data suggests an ordered superstructure, but negative stain TEM images and fibre X-ray diffraction have yielded only low resolution (~20 A) information. In this Thesis, I show that SAFs subjected to rapid plunge freezing and cryoTEM display a remarkable superstructure. Individual micrographs give high- resolution data that allowed direct structural interpretation of the packing of individual α-helices within the fibre, and the construction of a 3D electron density map at 8 A resolution. Furthermore, an all-atom model was derived combining the cryoTEM data and a 2.3 A X-ray crystal structure of a variant of the building block incapable of forming fibres. Together these provide the highest-resolution structure of a de novo designed protein-based supramolecular fibre. Green fluorescent protein (GFP) has revolutionised molecular and cell biology by enabling visualisation of endogenous proteins within live cells, providing information on protein motility, localisation and interactions. How- ever, the resolution of the light microscope (LM) is inherently limited by the wavelength of visible light, a problem that can be overcome by EM. However, EM requires a fixed cell. Correlative light electron microscopy (CLEM) combines the advantages of both techniques to allow visualisation of proteins in the live cell prior to detailed analysis at high resolution in the EM. At present there is no genetically encoded monomeric protein that is visible in both LM and EM. Therefore, the aim of the second project was to design and characterise a protein that was both fluorescent and electron dense. To achieve this, concatenation of a metal-binding protein, metallothionein (MT), was used to cluster heavy-metal ions into electron-dense nanoparticles. This was fused to Enhanced-GFP (EGFP) and characterised as a general-purpose "clonable" tag for use in CLEM. Metal binding capabilities were probed with mass spectrometry and dynamic light scattering. In vitro localisation of the probe in the EM was achieved by encapsulation within liposomes and fusion to SNXl, a membrane tabulating protein. In vivo, the probe was fused to various intra- and extracellular localisation domains and whole cell CL EM attempted. The probe proved difficult to visualise, oven after autometallography with gold. So, a separate complementary tag was also designed. A mutated intracellular protein, FK506 Binding Protein (FKBP12(F36V)), was fused to EGFP. FKBP12(F36V) has high affinity for a novel ligand (SLF'), which can be linked to a single gold particle and delivered to the cytoplasm. This would yield a fluorescent protein with an electron-dense particle nonco- valently bound. Preliminary studies are described towards this second goal, and results so far appear promising.
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Li, Xin. "High spatial and temporal resolution atmospheric emission inventory of road transport in Macau." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3868747.
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Anderson, Brett Nels. "Enhancing the temporal and spatial resolution of solid-state nanopore single-molecule sensors." Thesis, Boston University, 2013. https://hdl.handle.net/2144/10929.
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Thesis (Ph.D.)--Boston UniversitySince the first report of single-molecule detection using the biological nanopore alpha-hemolysin in 1996, nanopores have grown substantially more versatile. The genetic and chemical modification of biological nanopores and the fabrication of synthetic nanopores in solid-state membranes have enabled detection of analytes ranging in size from single nucleotides to large protein complexes. Among the most promising applications of nanopores is single-molecule sequencing, which has the potential to become a routine part of medical care, is compatible with long read lengths, and can detect epigenetically modified bases. Yet in order to further develop nanopores as useful tools for basic research as well as commercial applications, their temporal and spatial limitations must be addressed. Free electrophoretic threading of nucleic acids through a nanopore allows for discrimination based on large features (e.g., molecular length), but is too fast to resolve smaller features (e.g., single nucleotide identity). The first aim of this research is to enhance the temporal resolution of nanopores by tuning their electrostatic interaction with translocating molecules via chemical modification of the nanopore surface. To this end, we designed and fabricated pH-sensitive chemically coated nanopores to slow the translocation of DNA molecules. A practical nanopore sensing device relies on taking measurements from many pores in parallel to provide sufficient robustness (through redundancy) and throughput. Optical detection facilitates parallel throughput, but requires coupling between an analyte feature and a fluorescence source. The second aim is to enhance nanopore spatial resolution via optical detection of chemically activated fluorescence signals associated with single nanopores under total internal reflection (TIR) illumination. We performed numerical simulations of the concentration field of donor molecules near a nanopore and showed that nanopores are theoretically capable of discriminating between features separated by ~ 1 nm or less, a distance that far exceeds the resolution offered by TIR illumination. Finally, we use fluorescence signals to detect unlabeled DNA translocation through spatially addressed nanopores. With this aim we experimentally validate our theoretical predictions and demonstrate a novel highly parallel near-field chemo-optical detection scheme.
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Heimonen, K. (Kyösti). "Processing of visual information in dim light:functional variability, matched filtering and spike coding in cockroach (Periplaneta americana) photoreceptors." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514289491.
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Abstract
Sensory systems are considered to be optimized for their ecological niche. In vision this means highly organised regular structure and function, where nearly identical photoreceptors have graded light responses in order to be able to handle as much information as possible. Instead, cockroach compound eyes show large amounts of irregularities in their optics and structure, and unusually long axons.
In this thesis photoreceptors of the cockroach were studied with intracellular recordings of their light responses, biophysical systems analysis, and modelling of the relations between the light stimuli and responses. Cockroaches prefer living in dark or extremely dim environments. However, they have large and complex compound eyes. The aim of this study was to find out the functional properties by which the visual system and especially photoreceptors have adapted to cope with, i.e. to see in, dim light conditions.
The function of photoreceptors was found to vary randomly in many respects, and the long axons seemed to utilise action potential coding of visual signals. Through model simulations it was shown that signals of a group of these functionally variable and spiking photoreceptors, when pooled, could provide more reliable coding than signals of identical cells of any experimentally characterised type. This naturally sacrifices spatial resolution. The filtering dynamics of the photoreceptors is matched to low light intensities and their temporal resolution does not markedly improve with increasing light adaptation. Adaptation processes in the photoreceptors saturated near an intensity of about 1000 effective photons/s. These are all both unexpected and novel features of photoreceptor function. Spatial summation of functionally different photoreceptors and reduced temporal resolution and contrast coding abilities can be considered to be permanent optimizations to a dim environment.
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Nienborg, Hendrikje. "Neurons in striate cortex limit the spatial and temporal resolution for detecting disparity modulation." Diss., [S.l.] : [s.n.], 2005. http://edoc.ub.uni-muenchen.de/archive/00004922.
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Li, Mao Li. "Spatial-temporal classification enhancement via 3-D iterative filtering for multi-temporal Very-High-Resolution satellite images." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514939565470669.
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Jay, Steven Charles. "Detection of leafy spurge (Euphorbia esula) using affordable high spatial, spectral and temporal resolution imagery." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/jay/JayS0510.pdf.
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Leafy spurge is a designated noxious weed. Accurate mapping and monitoring of this species are needed to understand leafy spurge's extent and spread. Current methods are based on ground crews who survey patches. Development of an affordable technique to map and monitor leafy spurge would contribute to the control of this species. High spatial, temporal, and spectral resolution imagery was used to classify the amount of leafy spurge present with ground and aerial-based imagery. A proof of concept study was performed in 2008 using ground-based images of an area infested with leafy spurge. This proof of concept project guided the development of the methods to be used for the 2009 aerial portion of the study. Thirty-five randomly selected reference points were selected in a range area in southwest Montana. These reference points were ground surveyed to record the density of leafy spurge in a 0.5-m radius area around the reference point. Images were captured approximately 108-m from the study area and classified using random forest classification. Multiple images were collected throughout the summer in order to determine at which time period leafy spurge is most easily detected. A classification using multiple image dates was also performed to determine if a time series of images improves classification. Single date accuracies were highest late in the summer with the highest single date classification achieving 83% accuracy. The multiple date classification significantly increased overall accuracy. Several aerial images were acquired in southwest Montana over the 2009 summer. Fifty randomly selected 2-m x 2-m reference areas were surveyed for percent cover of leafy spurge as well as several other variables. Aerial images were collected at flight elevations between 300-m to 460-m. Classifications were performed using random forest classifier, and both single date and multiple date classifications were performed. Leafy spurge was most accurately detected early and late in the growing season, and significant classification accuracy increases were observed with the multiple date classification. Single date accuracies achieved 90% accuracy in early June, while multiple date classifications achieved over 96% accuracy.
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Menza, Marius [Verfasser], and Jürgen [Akademischer Betreuer] Hennig. "Accelerated, high spatial and temporal resolution phase contrast techniques for functional analysis of the myocardium." Freiburg : Universität, 2017. http://d-nb.info/1136567291/34.
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Abdullahi, Yelwa Sadiq. "Broadscale vegetation change assessment across Nigeria from coarse spatial and high temporal resolution AVHRR data." Göttingen Cuvillier, 2003. http://d-nb.info/990809595/04.
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Hossain, A. K. M. Azad. "Developing a virtual sensor (VS) for mapping soil moisture at high spatial and temporal resolution /." Full text available from ProQuest UM Digital Dissertations, 2008. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1798966761&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1258141491&clientId=22256.
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Thesis (Ph.D.)--University of Mississippi, 2008.Typescript. Vita. "December 2008." Committee chair: Dr. Greg Easson Includes bibliographical references (leaves 126-134). Also available online via ProQuest to authorized users.
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Hiersemenzel, Katia. "Super-resolution spatial, temporal and functional characterisation of voltage-gated calcium channels involved in exocytosis." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/2918.
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The process of information transfer between neurons or endocrine cells is one of the most important, intricate and temporally precise processes in the body. Exocytosis, which is central to the process of excitation-‐secretion coupling, is triggered by calcium signalling through voltage-‐gated calcium channels. Super-‐resolution imaging offers the possibility to fully understand the spatial relationship between the SNARE proteins involved in exocytosis, vesicles and the associated voltage-‐gated calcium channels. In this thesis the focus is on exploring the trigger for exocytosis, specifically the spatial and functional role that voltage-‐gated calcium channels play in this process. Super-‐ resolution imaging techniques have been applied to measure the interaction between Cav2.2 calcium channels and the syntaxin1a SNARE protein, where binding was found to affect the overall channel distribution. A novel method of caged dye conjugated ω-‐ conotoxin GVIA binding was developed for live cell single molecule imaging of Cav2.2 calcium channels. An innovative approach to analyse channel functionality and the distribution of calcium events at the plasma membrane was developed to create a temporal-‐spatial map of calcium activity across the cell. These developments, combined with newly developed techniques in optical patching and simultaneous calcium and vesicle imaging reveal the functional relationship of voltage-‐gated calcium channel and exocytosis at unprecedented spatial and temporal scales.
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Lorach, Henri. "Visual rehabilitation : spatial and temporal resolution with three dimensional implants and neuromorphic event-based visual sensor." Paris 6, 2012. http://www.theses.fr/2012PA066419.
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La cécité est l’une des atteintes sensorielles les plus handicapantes dans notre société et touche plus de 39 millions de personnes à travers le monde. Pour certaines de ces pathologies, il n’existe aucune stratégie thérapeutique et le seul espoir pour les patients est la réhabilitation prosthétique. Le principe est de stimuler les neurones du système visuel afin de fournir les informations nécessaires pour retrouver une certaine autonomie et accomplir des taches de tous les jours comme la reconnaissance d’objets, de visages, la lecture ou la navigation spatiale. Cette thèse présente le développement de deux principaux outils pour améliorer la réhabilitation visuelle chez les patients implantés. Dans une première partie, nous présentons le développement de structures tridimensionnelles pour les implants rétiniens. Cette configuration permet l’intégration du tissu nerveux cible au plus près des électrodes de stimulation et en augmente la résolution en limitant les interactions entre pixels voisins. De tels implants ont été réalisés et testés chez un modèle animal de dégénérescence rétinienne. La seconde partie de ce travail décrit le développement d’un système d’encodage dont le but est de transformer le signal visuel en pattern de stimulation des cellules de la rétine. Cet encodage est nécessaire pour fournir un signal pertinent au cerveau. Ce système d’encodage est basé sur une caméra asynchrone qui fournit la résolution temporelle nécessaire pour modéliser le traitement de l’information effectué par la rétine. Ces deux principales technologies seront intégrées dans une future génération d’implants rétiniens et testées chez des patients aveugles dans les années à venir
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Ge, Linlin School of Geomatic Engineering UNSW. "Development and Testing of Augmentations of Continuously-Operating GPS Networks to Improve Their Spatial and Temporal Resolution." Awarded by:University of New South Wales. School of Geomatic Engineering, 2000. http://handle.unsw.edu.au/1959.4/17867.
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Continuously-operating networks of GPS receivers (CGPS) are not capable of determining the characteristics of crustal deformation at the fine temporal or spatial scales required. Four ???temporal densification schemes??? and two 'spatial densification schemes' to augment the CGPS networks have been developed and tested. The four ???temporal densification schemes??? are based on the high rate Real-Time Kinematic (RTK) GPS technique, GPS multipath effects, Very Long Baseline Interferometry (VLBI) and Satellite Laser Ranging (SLR). The 'serial scheme' based on using GPS as a seismometer has been proposed. Simulated seismic signals have been extracted from the very noisy high rate RTK-GPS results using an adaptive filter based on the least-mean-square algorithm. They are in very good agreement with those of the collocated seismometers. This scheme can improve the CGPS temporal resolution to 0.1 second. The 'retro-active scheme' takes advantage of the fact that the GPS multipath disturbance is repeated between consecutive days. It can therefore provide a means of correcting multipath errors in the observation data themselves. A reduction of the standard deviations of the pseudo-range and carrier phase multipath time series to about one fourth and one half the original values respectively, has been demonstrated. The 'all-GPS parallel scheme' uses the multipath effects as a signal to monitor the antenna environment. Models relating the changes of multipath and antenna environment have been derived. The 'cross-technique parallel scheme' integrates the collocated CGPS, VLBI and SLR results, taking advantage of the decorrelation among their biases and errors. Crustal displacement signature has been extracted as a common-mode signal using data from two stations: Matera in Italy and Wettzell in Germany. Two 'spatial densification schemes' which can verify with each other have been developed and tested. The 'soft' scheme integrates CGPS with radar interferometry (InSAR). The Double Interpolation and Double Prediction (DIDP) approach combines the strengths of the high temporal resolution of CGPS and the high spatial resolution possible with the InSAR technique. This scheme can improve the spatial resolution to about 25m. The 'hard' scheme requires the deployment of single-frequency receivers to in-fill the present CGPS arrays. Alternatively some receivers may be installed at some geophysically strategic sites outside existing CGPS arrays. The former has been tested within Japan's GEONET, while the latter has been tested using a five-station array.
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Leite, Francisca Maria Pais Horta. "Detection power, temporal response, and spatial resolution of IRON fMRI in awake, behaving monkeys at 3 Tesla." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38593.
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Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, February 2007."September 2006."
Includes bibliographical references.
The main goal of this thesis was to systematically characterize the detection sensitivity, temporal response, and spatial resolution of IRON contrast for fMRI within the awake, behaving monkey. Understanding these issues provides insights into the physiology of the functional response to local changes in brain activity, enables researchers to optimize experimental designs, and delineates the advantages and limitations of neuroimaging within this important animal model. The injection of the iron oxide contrast agent (MION) provided a 9-fold increase in efficiency for block designs relatively to BOLD contrast. Because the hemodynamic response function acts as a low-pass filter on neural activation to attenuate the size of differential responses to alternate stimuli, this factor dropped to approximately 2 for rapidly presented stimuli. Detection efficiency for event-related stimulus designs for BOLD and IRON contrasts could be optimized using random or semi-random distributions for interstimulus intervals. Small increases in predictability could be traded for large gains in efficiency, particularly for the IRON method. A general linear model was successfully employed to describe IRON and BOLD impulse response functions. Both responses were accurately described by a bimodal exponential model with similar time constants, a fast (4.5 sec) and a slow (13.5 sec).
(cont.) The slow response comprised 80% of IRON signal, and was responsible for the BOLD post-stimulus undershoot. It likely encompasses changes in post-arteriole blood volume. Optimized IRON activation maps do not show activation in draining veins or draining tissue, in contrast with BOLD contrast. To examine what happens at the level of small vessels and capillaries, we used point-image stimuli to measure IRON and BOLD point spread functions (PSF) in V1. We estimated an IRON PSF no larger than approximately 0.4 mm, and a BOLD PSF with twice the size. Severe image distortions arising from monkey's body motion outside of the field of view currently limit the achievable spatial resolution. Preliminary data suggests multi-shot EPI with navigators may be useful in improving image stability at higher resolution for IRON fMRI, which can employ short echo times to minimize phase variations, while achieving maximum efficiency by increasing the MION dose.
by Francisca Maria Pais Horta Leite.
Ph.D.
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Ahmadi, Samim [Verfasser], Mathias [Akademischer Betreuer] Ziegler, Peter [Akademischer Betreuer] Jung, Giuseppe [Gutachter] Caire, Peter [Gutachter] Burgholzer, and Agustin [Gutachter] Salazar. "Super resolution laser thermography using spatially and temporally structured heating / Samim Ahmadi ; Gutachter: Giuseppe Caire, Peter Burgholzer, Agustin Salazar ; Mathias Ziegler, Peter Jung." Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1238143164/34.
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Molero, Rodenas Beatriz Molero. "Différence d'échelle spatiale entre les mesures satellitaires et in situ d'humidité du sol : analyse par des approches spatio-temporelles." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30264/document.
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L'humidité du sol est une variable climatique essentielle dont le suivi à l'échelle globale est possible grâce à des instruments micro-ondes à bord des satellites. La précision de ces estimations est validée par comparaison directe aux mesures au sol. Tandis que les estimations satellitaires ont des résolutions allant de 30 à 100 km, les capteurs in situ sont généralement représentatifs d'une zone de quelques centimètres (résolution ponctuelle). Cette différence entre l'échelle spatiale des estimations satellitaires et in situ impacte le processus de validation et les statistiques obtenues à un niveau qui n'est pas connu actuellement. Cette thèse vise à améliorer la connaissance de l'impact du changement d'échelle spatiale, ainsi qu'à fournir des méthodes d'évaluation de celle-ci applicables à toute zone de validation. Pour ce faire, la relation entre les échelles spatiales et temporelles a été étudiée. Des séries modélisées et mesurées sur des régions différentes du globe ont été décomposées en échelles de temps allant de 0,5 et 128 jours, en utilisant des transformées en ondelettes. La représentativité spatiale des mesures à résolution ponctuelle a ensuite été évaluée, par échelle de temps, avec 4 approches différentes : l'analyse de la stabilité temporelle, la triple colocation, le pourcentage de zones corrélées (CArea) et une nouvelle approche utilisant des corrélations basées sur des ondelettes (WCor). De plus, l'incertitude d'échantillonnage a été évaluée séparément avec des approches bootstrap et des simulations de Monte Carlo de séries à résolution ponctuelle. À l'issue de ces expériences, il y a été constaté que la moyenne des valeurs de représentativité spatiale obtenues tend à augmenter avec l'échelle de temps, mais aussi leur dispersion. Cela implique que certaines stations ont de vastes zones de représentativité à des échelles saisonnières, tandis que d'autres ne l'ont pas. Aux échelles sous-hebdomadaires, toutes les stations présentaient de très petites zones de représentativité. Enfin, l'impact de l'incertitude d'échantillonnage s'est avéré assez important dans les métriques de validation satellitaireSoil moisture is an essential climate variable that is globally monitored with the help of satellite borne microwave instruments. The accuracy of satellite soil moisture estimations is assessed by direct comparison to in situ measurements. While satellite estimates have a resolution ranging between 30 and 100 km, in situ sensors typically measure over an area of a few centimetres (point resolution). This spatial scale mismatch between satellite and in situ soil moisture estimates impairs the validation process and the respective summary statistics to an extent that is not currently known. This thesis aims at improving the knowledge of the spatial scale mismatch, as well as providing methods for its assessment applicable to any validation area. To this end, the connection between the SM spatial and time scales was investigated. Modelled and measured soil moisture series at different regions of the globe were decomposed into time scales ranging from 0.5 to 128 days, using wavelet transforms. The spatial representativeness of the point measurements was then assessed, on a per time scale basis, with 4 different approaches: temporal stability analysis, triple collocation, the percentage of correlated areas (CArea) and a new approach that uses wavelet- based correlations (WCor). Moreover, one of the components of the mismatch, the sampling uncertainty, has been assessed separately with bootstrap and Monte Carlo simulations of point-support series. It was found that the average of the spatial representativeness values tends to increase with the time scales but so does their dispersion. This implies that some stations had large representativeness areas at seasonal scales, while others do not. At sub-weekly scales, all stations exhibited very small representativeness areas. Finally, the sampling uncertainty has been observed to have a considerable impact on satellite validation statistics
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Llabrés, Brustenga Alba. "Intensity-Duration-Frequency of Rainfall in Catalunya. Maximum Expected Precipitation and IDF Relationships at High Temporal and Spatial Resolution." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/668777.
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Intensity - Duration - Frequency (IDF) relationships of extreme precipitation events are of high interest in hydrology. The building of infrastructure or designation of flood zone need, as groundwork, the recurrence intervals at which extreme episodes of rainfall can occur, i.e., the maximum intensities that can be expected for a given duration and return period.
In this project 2,142 series of daily rainfall data were analysed and quality controlled after the design of a new specific procedure. The newly proposed quality control is able to classify available rainfall series according to their quality and, using this information, performs a relative comparison with nearby measures to attain a quality category for each daily value (in this project 14,144,395 measures were checked and 74% of them were considered reliable). Afterwards, climatic homogeneity of a selection of series was checked and 163 daily rainfall data series of high quality data in the temporal period 1942-2016 and uniformly distributed over the territory of Catalonia were used in the obtainment of Intensity-Duration-Frequency relationships.
The obtainment of IDF was achieved by a temporal monofractal downscaling methodology implemented on a grid of high spatial resolution (1 km x 1 km) of maximum expected intensity in 24 hours. The spatial grid of maximum expected intensity in 24 hours at several return periods (2, 5, 10, 20, 50, 100, 200 and 500 years) was obtained from annual maximum precipitation in one day after correcting daily measures with an empirical factor thoroughly analysed in the scope of the project. The monofractal downscaling methodology was implemented after the obtainment of a single scaling exponent at the 163 selected locations; the scaling exponent was studied in relation to geographical and climatic characteristics of the study area.
The final results of IDF relationships are provided as a set of maps that display the maximum expected intensity at a selection of durations (daily and subdaily, namely: 1h, 6h, 12h, 24h and 48h) and for a selection of return periods. The results are of high spatial resolution as they are obtained in a spatial grid of 1 km x 1 km. The results also have high temporal resolution as the intensity - frequency relationship can be calculated at any duration at the locations of the grid nodes using the provided empirical scaling exponent with validity as long as the duration ranges between 1 hour and 15 days.Les relacions d’Intensitat-Duració-Freqüència (IDF) d’episodis de pluja extrems són de gran interès en hidrologia on es necessita, com a base, els intervals de recurrència en què es donen les precipitacions extremes, és a dir, la intensitat màxima que es pot esperar per una durada i període de retorn determinats. En aquest projecte, es van analitzar 2.142 sèries de precipitació mitjançant un nou control de qualitat especialment dissenyat per a aquestes dades. El control de qualitat proposat és capaç de classificar les sèries de precipitació disponibles segons la qualitat de les dades i, utilitzant aquesta informació, fa una comparació relativa amb mesures properes per assignar una categoria a cada un dels valors diaris (es van analitzar 14.144.395 mesures i un 74% d’elles es consideren bones). També es va realitzar un control d’homogeneïtat climàtica d’una selecció de les sèries disponibles. Per obtenir la relació IDF es va fer una selecció de 163 sèries de precipitació diària de bona qualitat en el període 1942-2016 i uniformement distribuïdes pel territori de Catalunya. Les relacions IDF es van obtenir amb un mètode monofractal de downscaling temporal implementat en un grid d’alta resolució espacial (1 km x 1 km) de la intensitat màxima esperada en 24 hores. Aquest grid espacial per diversos períodes de retorn (2, 5, 10, 20, 50, 100, 200 i 500 anys) es va obtenir a partir de les sèries anuals de màxims de precipitació diària després de corregir les mesures amb un factor de correcció empíric detingudament analitzat dins del projecte. El downscaling temporal monofractal es va implementar havent obtingut un únic exponent d’escala per cada una de les 163 localitats seleccionades; l’exponent d’escala va ser àmpliament estudiat en relació amb les característiques geogràfiques i climàtiques de l’àrea d’estudi. Els resultats finals de les relacions IDF es proporcionen en un conjunt de mapes que mostren la precipitació màxima esperada a una selecció de durades (diàries i subdiàries: 1h, 6h, 12h, 24h i 48h) i per una selecció de períodes de retorn. Els resultats són d’alta resolució espacial perquè s’obtenen en un grid de 1 km x 1 km. Els resultats també són d’alta resolució temporal perquè la relació entre intensitat i freqüència es pot calcular per qualsevol durada en els nodes del grid utilitzant l’exponent d’escala proporcionat (que té validesa entre 1 hora i 15 dies).
La relación de Intensidad-Duración-Frecuencia (IDF) de episodios extremos de lluvia es de gran interés en hidrología, donde se necesitan, como base, los intervalos de recurrencia de precipitaciones extremas, por lo tanto, la intensidad máxima esperada en una duración y período de retorno determinados. En este proyecto, se analizaron 2.142 series de precipitación por medio de un nuevo control de calidad especialmente diseñado para estos datos. El control de calidad propuesto es capaz de clasificar las series de precipitación disponibles según la calidad de los datos y, usando esta información, compara relativamente con medidas cercanas para asignar una categoría a cada valor diario (se analizaron 14.144.395 medidas y un 74% de ellas se consideraron buenas). También se realizó un control de homogeneidad climática de las series disponibles. Para obtener la relación IDF se seleccionaron 163 series de precipitación diaria de buena calidad en el período 1942-2016, uniformemente distribuidas por el territorio de Cataluña. La relación IDF se obtuvo con un método monofractal de downscaling temporal implementado en un grid de alta resolución espacial (1 km x 1 km) de intensidad máxima esperada en 24 horas. Este grid espacial para diferentes períodos de retorno (2, 5, 10, 20, 50, 100, 200 y 500 años) se construyó a partir de las series anuales de máxima precipitación diaria después de corregir las medidas con un factor de corrección empírico detenidamente analizado dentro del proyecto. El downscaling temporal monofractal se implementó tras la obtención de un único exponente de escala para cada una de las 163 localidades seleccionadas; el exponente de escala fue ampliamente estudiado en relación con las características geográficas y climáticas del área de estudio. Los resultados finales de la relación IDF se proporcionan en un conjunto de mapas que muestran la precipitación máxima esperada en una selección de duraciones (diarias y subdiarias: 1h, 6h, 12h, 24h y 48h) y para una selección de períodos de retorno. Los resultados son de alta resolución espacial porque se obtienen en un grid de 1km x 1km. Los resultados también son de alta resolución temporal porque la relación entre intensidad y frecuencia se puede calcular para cualquier duración en los nodos del grid usando el exponente de escala proporcionado (valido entre 1 hora y 15 días).
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Liu, Yuan. "Development of a tool to estimate the atmospheric emissions with high spatial and temporal resolution over the Macau SAR." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3868750.
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Little, Hazel Jean. "Quantifying spatial and temporal scales of phytoplankton variability in the Sub-Antarctic Ocean using a high-resolution glider dataset." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23060.
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Phytoplankton in the Sub-Antarctic Southern Ocean have a distinct seasonal cycle, which is highly variable in both space and time. The seasonal and spatial distribution of chlorophyll can be attributed to the complex nature of the physical and biogeochemical factors controlling phytoplankton production. Studies show that high-resolution sampling is required to understand variability in phytoplankton distribution and primary production. In this study, high-resolution glider data sampled in the Atlantic Sub-Antarctic Zone are used to characterise the scales of phytoplankton variability. Continuous glider data provide a novel way to assess phytoplankton variability at small time and space scales (meso- to submesoscale), especially in an area that has a lack of continuous measurements, which are necessary for addressing climate related questions. Temporal variability of phytoplankton was investigated using Empirical Mode Decomposition of surface chlorophyll-a concentrations collected from a Seaglider over a period of 5.5 months (25 September 2012 to 15 February 2013). This study found that during spring, chlorophyll-a concentrations were dominated by small scale daily fluctuations as well as by the rising seasonal ramp due to seasonal stratification. The removal of these signals revealed that the chlorophylla variability was dominated by submesoscales. In spring, phytoplankton blooms occurred as a result of features that shoaled the mixed layer depth when the wind stress weakened, elevating light conditions for short periods and allowing increased growth. In summer phytoplankton blooms were found to occur at submesoscales periods as well. This variability was found to be driven by synoptic storms varying the strength of the wind stress and consequently the mixed layer depth (that alters the nutrient and light environment). Additionally, through reconstructing the time series through subsampling at the dominant signals, this study found that in order to accurately resolve and characterise the multiseasonal variability of phytoplankton, chlorophyll needs to be sampled at high frequencies (<10 days). Spatial variability was investigated using daily MODIS ocean colour and sea surface temperature images coincident with the glider track. Spatial variability was characterised by the variance calculated at different length scales. Spatial analysis found that phytoplankton were patchier in both spring and summer when compared to sea surface temperature, at all length scales and that a greater variance was contained at small scales. There was also a greater variance in summer chlorophyll-a compared to spring due to higher maximum biomass. Further spatial analysis compared satellite spatial variance with glider measurements at the same length scale (70 km). This study found that a third of the variability found by the glider was caused by spatial patchiness, while the remainder could be contributed by local growth. These dominant meso- and submesoscale changes in chlorophyll-a at both temporal and spatial scales, highlights the need to resolve for both meso- to submesoscales in order to accurately reflect phytoplankton seasonal variability and ultimately to understand the impact of phytoplankton variability on carbon flux.
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Minnich, Sara Louise. "Enhancement of temporal and spatial resolution of 2-D reflection data : application to Texaco data over Venice Dome in Plaquemines Parish, Louisiana /." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11012008-063747/.
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Martin, Christopher M. "Studies of structural variation in synthetic organic polymers using X-ray fibre diffraction techniques at high temporal and spatial resolution." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327630.
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Hilfiker, Stephen Glenn. "High-Resolution Spatial and Temporal Analysis of the Aftershock Sequence of the 23 August 2011 Mw 5.8 Mineral, Virginia, Earthquake." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107179.
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Thesis advisor: John E. EbelStudies of aftershock sequences in the Central Virginia Seismic Zone (CVSZ) provide critical details of the subsurface geologic structures responsible for past and (possibly) future earthquakes in an intraplate setting. The 23 August 2011 MW 5.8 Mineral, Virginia, earthquake, the largest magnitude event recorded in the CVSZ, caused widespread damage and generated a lengthy and well-recorded aftershock sequence. Over 1600 aftershocks were recorded using a dense network of seismometers in the four months following the mainshock, offering the unique opportunity to study the fault structure responsible for the post-main event seismicity. Previous work has not accurately determined the geometry of the fault structure or the migration of post-mainshock seismicity and association of the 2011 event with a known fault has been unsuccessful. In this study, relative locations of recorded aftershocks were calculated using a version of the double-difference location method outlined in Ebel et al. (2008) to generate an accurate model of the fault structure. The moment tensor inversion technique of Ebel and Bonjer (1990) was used to generate focal mechanisms of dozens of the aftershocks at various locations on the fault structure. Results from the double-difference and moment tensor inversion methods were used to map the structure responsible for the aftershock sequence in high resolution. The calculated fault structure has planes with similar strikes and dips as known faults and geologic structures in the CVSZ. In-depth analysis of this aftershock sequence provides seismologists with the opportunity to better understand the seismic hazards present in poorly understood intraplate seismic zones
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
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Zwaschka, Gregor [Verfasser]. "Shining New Light on Water Electrolysis: Probing Electrolytic Water Splitting on Au and Pt with Micron Spatial and Femtosecond Temporal Resolution / Gregor Zwaschka." Berlin : Freie Universität Berlin, 2021. http://d-nb.info/1224883977/34.
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Hegebarth, Daniela. "Cuticular wax analyses with high spatial and temporal resolution lead to the identification and characterization of novel wax biosynthesis genes in Arabidopsis thaliana." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58833.
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Plant cuticles seal above-ground organs against non-stomatal water loss, and therefore are vital for survival on land. Besides providing a transpiration barrier, cuticles have important secondary functions, for example to protect from harmful UV radiation, and to provide a self-cleaning mechanism and mechanical support. Cuticles consist of aliphatic very-long-chain wax compounds (C₂₄ to C₃₈) and a cutin polymer. The diversity of cuticular wax compositions across the plant kingdom but also between different organs and ontogenetic stages is remarkable, yet the regulating mechanisms and function of those chemical differences are largely unknown. In the study presented here, a new approach was used, increasing temporal and spatial resolution and integration of chemical wax analyses with analyses of gene expression patterns of wax biosynthesis genes, using Arabidopsis thaliana as a model organism. The aims of the study were to, first, monitor wax composition and gene expression as a function of leaf development as well as different epidermal cell types and, second, to use this information to identify new wax biosynthesis genes.
In the second chapter, high temporal resolution was used to follow the dynamics of wax chemistry and gene expression during development of Arabidopsis thaliana leaves, and I was able to link changes in wax chemistry to differential expression of the elongation enzyme KCS6/CER6.
In the third chapter, wax analyses and gene expression data with high spatial resolution were acquired, and I identified differences between Arabidopsis epidermal cell types in wax composition and gene expression. Trichomes had a higher abundance of longer chain waxes (C₃₂ to C₃₈) compared to pavement cells, and the KCS5, KCS8 and KCS16 elongation enzymes were identified as candidates for the elongation of C₃₄₊ waxes. In the fourth chapter, I characterized the Arabidopsis condensing enzyme KCS16 and was able to show that it is functioning on the wax elongation pathway, elongating C₃₄ to C₃₈ acyl-CoA wax precursors, mainly in trichomes but also in pavement cells.Science, Faculty of
Botany, Department of
Graduate
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Vempala, Alakananda. "Extracting Temporally-Anchored Spatial Knowledge." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505146/.
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In my dissertation, I elaborate on the work that I have done to extract temporally-anchored spatial knowledge from text, including both intra- and inter-sentential knowledge. I also detail multiple approaches to infer spatial timeline of a person from biographies and social media. I present and analyze two strategies to annotate information regarding whether a given entity is or is not located at some location, and for how long with respect to an event. Specifically, I leverage semantic roles or syntactic dependencies to generate potential spatial knowledge and then crowdsource annotations to validate the potential knowledge. The resulting annotations indicate how long entities are or are not located somewhere, and temporally anchor this spatial information. I present an in-depth corpus analysis and experiments comparing the spatial knowledge generated by manipulating roles or dependencies. In my work, I also explore research methodologies that go beyond single sentences and extract spatio-temporal information from text. Spatial timelines refer to a chronological order of locations where a target person is or is not located. I present corpus and experiments to extract spatial timelines from Wikipedia biographies. I present my work on determining locations and the order in which they are actually visited by a person from their travel experiences. Specifically, I extract spatio-temporal graphs that capture the order (edges) of locations (nodes) visited by a person. Further, I detail my experiments that leverage both text and images to extract spatial timeline of a person from Twitter.
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Kraieva, Olena. "New approaches for high spatial and temporal resolution nanothermometry : development of hot wire nano heater devices and investigation of thermosensitive materials with fluorescent and spin crossover properties." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30315.
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L'objectif de cette thèse était de développer de nouvelles méthodes micro- et nano-thermométriques proposant de hautes résolutions spatiales et temporelles. Dans ce cadre nous nous sommes concentrés sur deux tâches : dans un premier temps, nous avons développé un dispositif de nano-chauffage qui peut aisément servir à la caractérisation thermo-physique de matériaux à l'échelle nanométrique. Dans un second temps, en utilisant cette plate-forme nous avons étudié des matériaux thermosensibles, incluant divers luminophores et des complexes à transition de spin ainsi que leurs mélanges. Les dispositifs de nano-chauffage, basés sur des nanofils chauffés par effet Joule, ont été fabriqués par lithographie électronique conventionnelle. Grâce à leur faible inertie thermique, les dispositifs basés sur des nanofils sont particulièrement intéressants en termes de temps de réponse et de confinement des changements de température induits. La caractérisation thermique de ces éléments de chauffage a été réalisée à l'aide de méthodes électriques et optiques ainsi que de simulations par éléments finis. Nous avons montré expérimentalement que nos chauffages prodiguent des perturbations en température (1 K < DeltaT < 80 K) rapides (< µs) et spatialement localisées (< µm) lorsque stimulées par des impulsions de courant électrique. Les simulations par éléments finis reproduisent ces résultats expérimentaux avec une bonne précision et prouvent ainsi leur intérêt pour le design de tels dispositifs. Les performances thermométriques de matériaux fluorescents, incluant des colorants organiques (Rhodamine B), des nanoparticules inorganiques (PbF2:Er3+/Yb3+, CdSe) et des nanoparticules hybrides organiques/inorganiques ([Fe(Htrz)2(trz)]BF4@SiO2-pyrene), ont ensuite été étudiées. D'une manière générale, leur intérêt pour l'imagerie thermique a été démontré, mais des problèmes de stabilité rendent les mesures quantitatives difficiles avec de tels matériaux. D'un autre côté, nous avons réussi à synthétiser des films de nanoparticules du complexe à transition de spin [Fe(Htrz)2(trz)]BF4 (non-dopé). Ces films qui nous ont permis de suivre les changements de température à l'aide de mesures de réflectivité optique plus robustes. La boucle d'hystérèse thermique dans ce matériau procure un effet de mémoire thermique à long terme dont nous avons usé avec succès pour imager les changements de température très rapides (< µs) et spatialement localisés (< µm) - même après que la chaleur se soit dissipée. Cette méthode originale nous procure une combinaison sans précédent de sensitivité spatio-temporelle dans le champ de la nano-thermométrie aux applications pratiques prometteusesThe overall objective of this PhD thesis was to develop novel micro- and nano-thermometry methods providing high spatial and temporal resolution thermal imaging. To achieve this goal we have focused on two tasks: First, we developed a nano-heater device that can be easily employed for the thermo-physical characterization of materials at the nanoscale. In a second time, using this platform we investigated thermo-sensitive materials, including different luminophores and spin crossover complexes as well as their mixtures. The nano-heater device, based on Joule-heated metallic nanowires, was fabricated by standard electron beam lithography. Due to their small thermal mass, nanowire based devices are particularly interesting in terms of response times and also in terms of confinement of the induced temperature changes. The thermal characterization of these heating elements was carried out using electrical and optical methods as well as finite element simulations. We have shown experimentally that our heaters can provide fast (< µs) and spatially well localized (< µm) T-jump perturbations (1 K < DeltaT < 80 K) driven by an electrical current pulse. Finite element simulations reproduced these experimental results with good accuracy and proved to be a powerful tool of prediction for the device design. Fluorescent materials, including organic dyes (Rhodamine B), inorganic nanoparticles (PbF2:Er3+/Yb3+, CdSe) and hybrid organic/inorganic nanoparticles ([Fe(Htrz)2(trz)]BF4@SiO2-pyrene), were then investigated for their thermometry performance. Overall, they were found useful for thermal imaging, but stability problems make quantitative measurements challenging with these materials. On the other hand, we have succeeded in synthesizing nanoparticle films of the (undoped) [Fe(Htrz)2(trz)]BF4 spin crossover complex, which allowed us to infer temperature changes through more robust optical reflectivity measurements. The thermal hysteresis loop in this material provides a long-term thermal memory effect which we used successfully to image very fast (˜µs) transient temperature changes with high spatial resolution (sub-µm) - even when the heat is dissipated. This original method provides an unprecedented combination of spatio-temporal sensitivity within the field of nanothermometry with promising potential applications
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Schwenke, Hannes Verfasser], Klaus [Akademischer Betreuer] [Willmes, and Klaus [Akademischer Betreuer] Mathiak. "Detailing reliability estimation of the individual working brain by varying spatial and temporal resolution in accelerated echo planar MR imaging / Hannes Schwenke ; Klaus Willmes-von Hinckeldey, Klaus Mathiak." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1126040800/34.
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Schwenke, Hannes [Verfasser], Klaus [Akademischer Betreuer] Willmes, and Klaus [Akademischer Betreuer] Mathiak. "Detailing reliability estimation of the individual working brain by varying spatial and temporal resolution in accelerated echo planar MR imaging / Hannes Schwenke ; Klaus Willmes-von Hinckeldey, Klaus Mathiak." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1126040800/34.
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Görner, Christina [Verfasser], Christian [Gutachter] Bernhofer, Christian [Akademischer Betreuer] Bernhofer, Niels [Gutachter] Schütze, and Uwe [Gutachter] Müller. "Testing and improving the spatial and temporal resolution of satellite, radar and station data for hydrological applications / Christina Görner ; Gutachter: Christian Bernhofer, Niels Schütze, Uwe Müller ; Betreuer: Christian Bernhofer." Dresden : Technische Universität Dresden, 2021. http://d-nb.info/123774833X/34.
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Laband, Kimberley. "Mechanisms of chromosome segregation in the C. elegans oocyte." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC275.
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Les gamètes femelles appelés ovocytes sont produits par un type spécifique de division cellulaire appelée méiose. Afin de produire des gamètes haploïdes, et contrairement aux divisions mitotiques des cellules somatiques, la méiose implique une seule étape de réplication du génome suivie de deux étapes de ségrégation des chromosomes. La fidélité de la ségrégation des chromosomes pendant la méiose est cruciale pour éviter l’aneuploïdie embryonnaire qui entraînerait des défauts de développement ou un avortement spontané. Dans la plupart des types cellulaires, la ségrégation des chromosomes repose sur un fuseau composé de microtubules. En parallèle à l'assemblage du fuseau, des complexes multi-protéiques appelés kinétochores s’assemblent sur le côté des chromosomes et leur permettent d’interagir avec les microtubules dynamiques du fuseau. Étonnamment, la ségrégation des chromosomes dans l'ovocyte de C. elegans se déroule d'une manière atypique indépendante des kinétochores. Le mécanisme alternatif utilisé dans ces oocytes pour la ségrégation des chromosomes est cependant inconnu. Au cours de mon doctorat, j'ai utilisé une combinaison d'imagerie photonique à haute résolution temporelle, corrélée à de la microscopie électronique à haute résolution spatiale. J’ai également utilisé de la photoablation par laser des microtubules et réalisé l'inhibition ciblée de protéines clés pour disséquer le mécanisme atypique de ségrégation des chromosomes dans l'ovocyte de C. elegans. Mes résultats montrent que la ségrégation des chromosomes est produite par une force dépendante des microtubules qui pousse les chromosomes. Par une analyse détaillée de l’organisation des microtubules dans des fuseaux en anaphase partiellement reconstruits par microscopie électronique en tomographie, je propose un modèle impliquant la génération de force par l'allongement d’un réseau de courts microtubules formant le fuseau central. De plus, je démontre que l'activité de l'orthologue de CLASP chez C. elegans (CLS-2) est essentielle pour l'assemblage du fuseau en anaphase. Ce travail est actuellement sous presse dans le journal Nature Communications. Parallèlement, j'ai disséqué le rôle de CLS-2 dans l'assemblage du fuseau d'ovocytes et la ségrégation chromosomique. J'ai perturbé de manière systématique les domaines individuels et les résidus conservés de manière évolutive dans CLS-2 pour déterminer leur contribution à la fonction et à la localisation de cette protéine pendant la première méiose femelle. Dans l'ensemble, mes résultats montrent que la ségrégation chromosomique dans l'ovocyte de C. elegans consiste en un mécanisme de poussée chromosomique atypique et dépendant de CLS-2Female gametes called oocytes are produced through a specific type of celldivision termed meiosis. In order to produce haploid gametes, and unlike mitoticdivisions of somatic cells, meiosis involves a single round of genome replication followed by two rounds of chromosome segregation. Accuracy of chromosome segregation during meiosis is crucial to avoiding embryonic aneuploidy that wouldlead to developmental defects or spontaneous abortion. In most cell types,chromosome segregation relies on a microtubule-based spindle. Concomitant tospindle assembly, multi-protein complexes termed kinetochores assemble on the side of chromosomes and couple microtubule dynamics to chromosomal movements. Strikingly, in the C. elegans oocyte chromosome segregation occurs in an atypical kinetochore-independent manner. The alternative mechanism used in these oocytes for chromosome segregation is however unknown. During my PhD, I used a combination of high spatial and temporal resolution live imaging, correlated light and electron tomography, laser-mediated photoablation of microtubules, and targeted inhibition of key proteins to dissect this a typical mechanism of chromosome segregation in the C. elegans oocyte. Myresults show that chromosome segregation is driven by a microtubule-dependent force that pushes the segregating chromosomes apart during anaphase. Aftercareful analysis of partially reconstructed anaphase spindles by electrontomography for microtubule quantity, length, orientation, and overlaps, I proposea model involving the elongation and/or sliding of tiled microtubules in the central spindle as the candidate structure responsible for this force generation. Additionally, I demonstrate that the activity of the C. elegans CLASP ortholog CLS-2 is essential for proper anaphase spindle assembly. This work is currently in press at Nature Communications.In parallel, I have more closely examined the role of the C. elegans CLS-2 in oocyte spindle assembly and chromosome segregation. I have thoroughly and systematically perturbed the individual domains and evolutionarily conserved residues in CLS-2 to determine their contribution to the function and localization ofthis protein during the first female meiosis. Overall my results show that chromosome segregation in the C. elegans
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Bonato, Simon. "Étude de la variabilité spatiale et temporelle des communautés phytoplanctoniques en Manche Orientale - Utilisation de la cytométrie en flux de scanning." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0379/document.
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Le compartiment phytoplanctonique joue un rôle prépondérant dans les écosystèmes marins de par sa position comme principal producteur primaire et fixateur de carbone, mais aussi en raison de sa capacité de multiplication élevée, qui lui permet de réagir rapidement aux changements environnementaux et d'en faire un potentiel bio indicateur. La plupart des études antérieures ne se sont basées que sur des observations réalisées à basse fréquence, ou bien ne ciblant qu'une partie des groupes/espèces phytoplanctoniques entraînant une perte importante d'information sur la variabilité d'abondance et composition du phytoplancton. Cette thèse a été réalisée dans le cadre du projet européen transfrontalier DYMAPHY dont l'objectif principal visait à améliorer les connaissances et l'évaluation de la qualité des eaux marines de la Manche et de la Mer du Nord, à travers l'étude de l'ensemble du compartiment phytoplanctonique et ses paramètres complémentaires. Dans ce contexte, une approche à haute fréquence et/ou haute résolution spatiale, via l'utilisation de la cytométrie en flux semi-automatisée, a permis de mieux caractériser la variabilité spatiale et temporelle du phytoplancton en Manche Orientale. Pour cela on a utilisé 3 approches complémentaires dont les résultats principaux obtenus lors de ce travail de thèse sont les suivants : (i) une étude à haute fréquence, avec une analyse cytométrique toutes les 10 minutes, qui a permis de révéler une forte variabilité spatiale du phytoplancton, à une échelle régionale (Manche Orientale), dont l'assemblage communautaire n'était pas déterminé par l'hydrologie ; (ii) un suivi saisonnier de l'ensemble du spectre de taille des cellules phytoplanctoniques le long d'un gradient côte-large proche du détroit du Pas de Calais, qui a révélé, au-delà d'une certaine hétérogénéité spatiale, une forte variabilité temporelle permettant de définir les successions saisonnières et les principaux facteurs les régissant, à savoir la luminosité et la concentration en sels nutritifs ; (iii) un suivi de 3 ans sur un point fixe en eaux côtières, qui a permis de mettre en relation les traits de vie des groupes phytoplanctoniques avec l'environnement, afin de comprendre comment les communautés phytoplanctoniques s'assemblent en réponse à la variabilité environnementale. Les résultats ont montré une différenciation fonctionnelle liée à l'utilisation des ressources et des stratégies de croissance, associées à un gradient de ressources. Cette étude confirme notamment l'importance de "l'hypothèse du ratio de masse", qui prédit que les traits de vie de l'espèce la plus abondante au sein d'une communauté, seraient le moteur des processus les plus importants au sein d'un écosystèmePhytoplankton micro-organisms play a key role in marine ecosystems as main primary producers, being responsible for most of carbon uptake, but also due to their fast division rates which allow them to effectively react to environmental changes and which make them potentially good bio-indicators. Most previous studies have based their observations on low frequency sampling, only considering one fraction of phytoplankton communities, resulting in a significant loss of information on the dynamics of phytoplankton abundance and diversity. This thesis was carried out in the frame of the European cross-border DYMAPHY project, which main objective was to improve the understanding and the evaluation of the quality of marine waters in the English Channel and the North Sea, through the study of the whole phytoplankton compartment and related environmental parameters. A high frequency and/or high resolution approach, through the use of semi-automated flow cytometry, allowed us to reduce this loss of information and to better characterize the phytoplankton spatial and temporal variability in coastal water of the eastern English Channel.Three approaches were applied, leading to the ollowing results : (i) A high frequency study, performing one analysis every 10 minutes, which revealed a strong phytoplankton variability at the regional scale, with community assemblages that were not governed by hydrology ; (ii) A seasonal monitoring of the whole phytoplankton size-spectrum, which revealed the seasonal successions and the main factors governing them : nutrient concentrations and the daily light level which structured the transition of most phytoplankton groups ; (iii) A three-year follow-up at a coastal station, which made it possible to relate the traits-based characterization of each functional phytoplankton group to the environmental conditions, in order to better understand phytoplankton community assembly in response to environmental variability. The results have revealed a functional differentiation mainly due to the use of resources and the growth strategies, both of them driven by a resource gradient. This study confirms the importance of the "mass ration hypothesis", which predicts that the dominant life traits of the most abundant species, would be the main driver of the key ecosystem processes
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Bonilla, Riaño Adriana 1980. "Film thickness measurement with high spatial and temporal resolution planar capacitive sensing in oil-water pipe flow = Medida da espessura de filme usando sensor capacitivo de alta resolução espacial e temporal para escoamentos óleo-água em tubos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265764.
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Orientadores: Antonio Carlos Bannwart, Oscar Mauricio Hernandez RodriguezTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências
Made available in DSpace on 2018-08-28T09:34:02Z (GMT). No. of bitstreams: 1 BonillaRiano_Adriana_D.pdf: 7155927 bytes, checksum: 63be57b0a5136f5e783cfb4f870b0189 (MD5) Previous issue date: 2015
Resumo: Neste trabalho, é apresentado o desenvolvimento de uma nova técnica para a medição da espessura do filme de água com alta resolução espacial e temporal em escoamento óleo-água. É proposto o uso de um sistema de medição de capacitância elétrica para medir filmes finos de água na proximidade da parede do tubo. O sistema conta com um sensor planar e foi necessário determinar a melhor geometria via simulações baseadas no Método de Elementos Finitos (FEM) para o caso de escoamento óleo-água. As características comparadas foram a profundidade de penetração do campo elétrico no filme de água, a sensibilidade, a resolução espacial mínima e a resposta quase-linear. Padrões de escoamento óleo-água disperso e anular instável foram estudados numa tubulação vertical de 12 m de comprimento, feita de vidro, com 50,8 milímetros de diâmetro interno. Os fluidos usados foram óleo mineral (com densidade 828 kg/m3 e viscosidade 220 mPas) e água da torneira. O trabalho experimental foi realizado nas instalações de escoamento multifásico do Laboratório de Engenharia Térmica e Fluidos (NETeF) da EESC-USP. Foi medida a espessura média do filme de água usando o sistema capacitivo e uma câmera de vídeo de alta velocidade. Para obter a espessura do filme de água a partir das imagens, foi proposto um algoritmo de pré-processamento e um algoritmo de segmentação que combina vários métodos disponíveis na literatura. Os resultados experimentais do sensor capacitivo mostraram que o sistema pode medir espessuras entre 400 µm e 2200 µm. O escoamento anular instável é caracterizado por grandes flutuações na no sentido do escoamento e na direção do perímetro, e estruturas interfaciais grandes (gotas). Por sua vez, o escoamento disperso tem flutuações menores no sentido do escoamento e na direção do perímetro, e estruturas interfaciais menores (gotículas). Uma estrutura interfacial média no espaço e no tempo é proposta para modelar a interface entre a região próxima à parede do tubo e a região do núcleo, e sua análise foi feita no domínio do tempo e da frequência. Foram estudadas a amplitude, velocidade e o comprimento da estrutura interfacial em cada par transmissor-receptor do sensor. Foi possível estabelecer correlações para a velocidade das estruturas em escoamento de óleo em água
Abstract: The development of a new technique for high spatial and temporal resolution film thickness measurement in oil-water flow is presented. A capacitance measurement system is proposed to measure thin water films near to the wall pipe. A planar sensor was chosen for sensing and some geometries were compared using finite elements method (FEM). The penetration depth, the sensitivity, the minimum spatial resolution (high spatial resolution) and the quasi-linear curve were the analyzed characteristics. Dispersed and unstable-annular oil-water flows patterns were studied in a 12-m long vertical glass pipe, with 50.8 mm of internal diameter, using mineral oil (828 kg/m3 of density and 220 mPa s of viscosity) and tap water. The experimental work was carried out in the multiphase-flow facilities of The Thermal-Fluids Engineering Laboratory (NETeF) of EESC-USP. Experiments with a high-speed video camera and the proposed capacitance system were performed to obtain images of the oil-water flow near the pipe wall. A pre-processing enhancement algorithm and a combined segmentation algorithm are proposed and allowed the measurement of characteristic space and time averaged water film thickness. Experimental results of the capacitive technique showed that the system could measure thickness between 400 µm and 2200 µm. It was possible to recognize and characterize typical behaviors of the two different flow patterns studied. Unstable-annular flow can be described by huge fluctuations on the flow direction and perimeter direction, and big interfacial structures (drops). On the other hand, dispersed flow has tiny fluctuations on the flow direction and perimeter direction, and smaller interfacial structures (droplets). An interfacial structure is suggested in order to model the interface between wall and core regions and it was analyzed in time and frequency domains; amplitude, velocity and wavelength at each pair transmitter-receiver of the sensor were studied. Correlations for the interfacial structure velocity were found for dispersed oil-in-water flow and unstable-annular flow
Doutorado
Explotação
Doutora em Ciências e Engenharia de Petróleo
CAPES
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Koca, Thimjo. "Spatio-Temporal Regions in the Context of Aircraft En-route Tactical Con ict Resolution." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670589.
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Es preveu que la Gestió del Trànsit Aeri (ATM) canviï dràsticament. Per a satisfer la creixent demanda d’ús de l’espai aèri, s’esperen canvis dràstics en la present Gestió del Trànsit Aeri (ATM). Per l’horitzó de temps estratègic, que s’estén fins al 2050, Existeixen 2 línies de pensament que agrupen les diferents alternatives per a un horitzó de temps estratègic, que s’estén fins al 2050. Una es basa en un moviment cap a l’espai aeri no controlat i el concepte del vol lliure. L’altre busca moure’s cap a la direcció oposada, la de l’espai aeri totalment automatitzat i controlat. Més enllà de les seves diferències conceptuals, ambdues visions manifesten alguns components comuns. La necessitat d’una detecció i resolució de conflictes tàctica (CD&R) automatitzada en ruta és una d’elles.
Tot i que el tema de CD&R ha estat investigat a fons en les últimes tres dècades, existeixen diferents aspectes que no han estat tractats. En particular, les solucions proposades no mostren cert nivell de resiliència, no proporcionen una identificació completa del tràfic circumdant que podria veure’s afectat per la resolució del conflicte original, no permeten que els usuaris de l’espai aèri participin en la Resolució de Conflictes (CR) de manera realista (per aconseguir resolucions eficients), i no proporcionen els límits de temps de maniobra dins dels quals es poden aconseguir resolucions factibles.
Aquest treball aborda els problemes anteriors de la següent manera.
Es proposa l’ús de regions espacio-temporals en lloc de trajectòries úniques per aconseguir cert nivell de resiliència en la CR. A través del mètode proposat de “coll d’ampolla”, es quantifica el nivell de resiliència de les regions.
L’ “ecosistema aeri”, la construcció formal que serveix per aconseguir la identificació completa del tràfic circumdant rellevant, es defineix formalment per dotar al CR de la propietat de sistema completEs realitza una anàlisi del tràfic històric i projectat per a identificar la dimensió dels ecosistemes aeris formats.
La detecció de conflictes per parelles s’utilitza per construir un ecosistema aeri complet. Per a tractar casos en els quals coexisteixen diferents conflictes parells en el temps amb estreta dependencia espacial, s’amplia el concepte “d’ecosistema aeri” i es defineix l’ “ecosistema compost”. A més, es proposen algunes estratègies per a mitigar la dependència entre els conflictes per parelles dins de l’ecosistema compost. Es realitza una anàlisis del tràfic històric i sintètic per a identificar els ecosistemes compostos que es formen i provar l’efectivitat de les estratègies de mitigació proposades.
S’adopta un mecanisme de negociació automatitzat, a través del qual els usuaris de l’espai aèri poden participar activament en el procés de CR. El mecanisme proposat és descentralitzat, proporciona la integritat del procés d’identificació i ofereix cert nivell de resiliència. D’aquesta manera, els usuaris de l’espai aèri poden participar en el CR amb el propòsit d’augmentar l’eficiència sense revelar les seves preferències respecte dels seus costos i estratègies.
El mecanisme de negociació automatitzat s’enriqueix amb un enfocament inicial per a identificar els límits temporals del marc de resolució de conflictes per parelles de l’aeronau delegada. Aquesta informació s’utilitza per a determinar el límit temporal per al procediment de negociació automatitzat.Para hacer frente a la creciente demanda de uso del espacio aéreo, se esperan cambios drásticos en la presente Gestión del Tránsito Aéreo (ATM). Existen 2 líneas de pensamiento que agrupan las diferentes alternativas para un horizonte de tiempo estratégico, que se extiende hasta 2050. Una se basa en un movimiento hacia el espacio aéreo no controlado y el concepto de vuelo libre. La otra busca moverse hacia la dirección opuesta, la del espacio aéreo totalmente automatizado y controlado. Más allá de sus diferencias conceptuales, ambas visiones manifiestan algunos componentes comunes. La necesidad de una detección y resolución de conflictos táctica (CD&R) automatizada en ruta es una de ellas. Aunque el tema de CD&R ha sido investigado a fondo en las últimas tres décadas, existen varios aspectos que no han sido tratados. En particular, las soluciones propuestas no exhiben cierto nivel de resiliencia, no proporcionan una identificación completa del tráfico circundante que podría verse afectado por la resolución del conflicto original, no permiten que los usuarios del espacio aéreo participen en la Resolución de Conflictos (CR) de manera realista (para lograr resoluciones eficientes), y no proporcionan los límites de tiempo de maniobra dentro de los cuales se pueden lograr resoluciones factibles. Este trabajo aborda los problemas anteriores de la siguiente manera. Se propone el uso de regiones espacio-temporales en lugar de trayectorias únicas para lograr cierto nivel de resiliencia en la CR. A través del método propuesto de “cuello de botella”, se cuantifica el nivel de resiliencia de las regiones. El “ecosistema aéreo”, la construcción formal que sirve para lograr la identificación completa del tráfico circundante relevante, se define formalmente, para dotar al CR de la propiedad de sistema completo. Se realiza un análisis del tráfico histórico y proyectado para identificar el tamaño de los ecosistemas aéreos formados. La detección de conflictos por parejas se utiliza para construir un ecosistema aéreo completo. Para tratar casos en los que coexisten varios conflictos pares en el tiempo con estrecha dependencia espacial, se amplía el concepto de “ecosistema aéreo” y se define el “ecosistema compuesto”. Además, se proponen algunas estrategias para mitigar la dependencia entre los conflictos por parejas dentro del ecosistema compuesto. Se realiza un análisis del tráfico histórico y sintético para identificar los ecosistemas compuestos que se forman y probar la efectividad de las estrategias de mitigación propuestas. Se adopta un mecanismo de negociación automatizado, a través del cual los usuarios del espacio aéreo pueden participar activamente en el proceso de CR. El mecanismo propuesto es descentralizado, proporciona la integridad del proceso de identificación y ofrece cierto nivel de resiliencia. De esta manera, los usuarios pueden participar en el CR con el propósito de aumentar la eficiencia sin revelar sus preferencias con respecto a sus costes y estrategias. El mecanismo de negociación automatizado se enriquece con un enfoque inicial para identificar los límites temporales del marco de resolución de conflictos por parejas de la aeronave delegada. Esta información se utiliza para determinar el límite temporal para el procedimiento de negociación automatizado.
Air Traffic Management (ATM) is envisioned to change drastically in order to accommodate the increasing demand. For the strategic time horizon, that spans up to 2050, two lines of thoughts are presented. One of them supports a move towards non-controlled airspace and the concept of free flight. The other one seeks to move towards the opposite direction, that of fully automated, controlled airspace. Beyond their conceptual differences, both visions manifest some common components. The necessity for automatic tactical, en-route Conflict Detection & Resolution (CD&R) is one of them. Although the topic of CD&R has been heavily investigated the last three decades, several issues have not been treated by the literature. In particular, the proposed solvers do not exhibit some level of resilience, they do not provide a complete identification of the surrounding traffic that might be affected by the resolution of the original conflict, they do not allow airspace users to be involved in the Conflict Resolution (CR) in a realistic way in order to achieve efficient resolutions, and they do not provide the maneuver time limits within which feasible resolutions can be achieved. This work addresses the above issues in the following manner. The use of spatio-temporal regions instead of unique trajectories is proposed in order to achieve some level of resilience in the CR. Through the proposed “bottleneck” method, the regions’ level of resilience is quantified. The so called “aerial ecosystem”, the formal construct that serves to achieve complete identification of the relevant surrounding traffic, is formally defined in order to extend the CR with the completeness property. An analysis of historical and projected traffic in order to identify the size of the formed aerial ecosystems is performed. Pairwise conflict detection is used to construct a full aerial ecosystem. In order to treat cases when several pairwise conflicts co-exist in time with tight spatial bounds, the “aerial ecosystem” concept is extended and the “compound ecosystem” is defined. Moreover, some strategies to mitigate the dependence between the pairwise conflicts within the compound ecosystem are proposed. An analysis of historical and synthetic traffic is performed in order to identify the compound ecosystems that are formed and test the effectivity of the proposed mitigation strategies. An automated negotiation mechanism, through which airspace users can actively participate in the CR process is adopted. The proposed mechanism is decentralized, provides completeness of the identification process, and offers some level of resilience. In such a manner, airlines can participate in the CR with the purpose of increasing efficiency without revealing their preferences regarding their costs and strategies. The automated negotiation mechanism is enriched by an initial approach to identify the temporal fences of the delegated aircraft pairwise conflict resolution framework. This information is used to determine the deadline for the automated negotiation procedure.
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Zweynert, Ulrike. "Möglichkeiten und Grenzen bei der Modellierung von Nährstoffeinträgen auf Flussgebietsebene." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1239967648045-37533.
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Modelle werden eingesetzt, um Menge und Herkunft der Stoffeinträge auf Flussgebietsebene zu analysieren. Aus den Ergebnissen der Modellierung lassen sich Handlungsempfehlungen zur Verbesserung der Gewässergüte ableiten. Für die Interpretation der Modellergebnisse sind Kenntnisse über die Genauigkeit und Aussagekraft der Ergebnisse notwendig. Das Modell MONERIS als konzeptionelles Modell für die Anwendung auf Flussgebietsebene wurde innerhalb der vorliegenden Arbeit in 5 europäischen Flusseinzugsgebieten angewandt. Sowohl mit verschiedenen Ansätzen aufbereitete Abflusswerte als auch unterschiedlich hoch aufgelöste Eingangsdaten führten bei der Modellierung zu Änderungen der berechneten Einträge und Frachten. Gezeigt wird, dass mit MONERIS sowohl mittlere Eintrags- und Frachtwerte für eine Periode von mehreren Jahren, als auch Werte für Einzeljahre berechnet werden können. Der Vergleich mit aus Konzentrations- und Abflussmessungen im Gewässer abgeleiteten Frachten wies Abweichungen von <30% auf. Bei der Modellierung von Einzeljahren konnten insbesondere die Jahre mit mittleren Niederschlagsbedingungen gut abgebildet werden. In Jahren mit hohen oder geringen Niederschlägen oder einer außergewöhnlichen Niederschlagsverteilung traten dagegen, bedingt durch die Kalibrierung der meisten Modellkoeffizienten für mittlere Abflussbedingungen von Perioden, Unter- oder Überschätzungen der gemessenen Frachten auf. Monatliche Einträge und Frachten wurden ebenfalls modelliert. Der Vergleich mit Messwerten zeigte hohe Abweichungen, sodass MONERIS für eine monatliche Berechnung noch weiterentwickelt werden muss. Dies betrifft vor allem die Genauigkeit der als Eingangsdaten verwendeten Abflüsse und der Abflusskomponenten sowie den in den Modellversionen vor 2008 verwendeten Retentionsansatz. Auch die räumliche Modellauflösung wurde untersucht und festgestellt, dass eine Modellierung mit MONERIS bis zu einer Auflösung von 1km² problemlos möglich ist. Die Schnittpunkte von Stoffeintragsmodellen mit Modellen aus der Siedlungswasserwirtschaft wurden durch einen Vergleich von MONERIS mit dem Modell STORM in einem stark urban geprägten Einzugsgebiet ermittelt. Obwohl die Unterschiede in den Modellansätzen deutlich wurden, konnte gezeigt werden, dass eine Ergänzung der beiden Modelltypen wünschenswert wäre. Abschließend wird ein neuer Ansatz für die Frachtberechnung aus Abfluss- und Konzentrationsmessungen vorgestellt, durch den die Genauigkeit der berechneten Jahresfrachten bei geringer Anzahl von Messwerten gegenüber etablierten Ansätzen erhöht werden kann. Da die aus Messwerten berechneten Frachten für die Modellkalibrierung und Validierung benötigt werden, kann so auch die Stoffeintragsmodellierung positiv beeinflusst werdenDifferent models were used to analyse and calculate the amount and origin of the nutrient inputs into riverbasins. Recommended follow-up action can be derived from the model results to improve the river water quality. The interpretation of the modelling results requires the knowledge of the accurateness and the significance of the results. For the investigations, the MONERIS model as a conceptual model was applied in five European river catchments. Different approaches for data preparation as well as a different input data were resulting in a large variation of the calculated nutrient inputs and loads. It was shown, that the MONERIS model is applicable to calculate inputs and loads for periods of several years as well as for one year. In comparison with measured loads mean deviations less than 30% were found. Looking at a yearly timestep, the nutrient inputs and loads in years with mean precipitation conditions were well reproduced. Years with high or low precipitation tends to result in overor underestimation of the nutrient inputs and loads, caused by the calibration of the model coefficients for mean runoff conditions. Monthly inputs and loads were calculated with MONERIS for the first time. The comparison with measured loads shows high deviations. Model improvements have to bee made regarding runoff input values (and runoff components) and retention approach (in the model version before 2008). Furthermore the spatial model resolution was investigated. It could be shown, that the MONERIS model is applicable until a resolution of 1sq.km. In a further application, MONERIS was compared with the urban stormwater management model STORM. Even though there were differences in model approaches, it could be shown a relation between the models for a comprehensive consideration of the calculation of nutrient contamination. Subsequent, a new runoff reduced approach for load calculation based on measurements of runoff and concentrations is presented. This approach allows the calculation of yearly loads with higher precision compared with well-established approaches, if only a low number of concentration measurement is available. The loads calculated from runoff and concentration measurements were important for calibration and validation of nutrient input models and can help to improve there results
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Zweynert, Ulrike. "Möglichkeiten und Grenzen bei der Modellierung von Nährstoffeinträgen auf Flussgebietsebene: Untersuchungen am Beispiel des Modells MONERIS." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23599.
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Modelle werden eingesetzt, um Menge und Herkunft der Stoffeinträge auf Flussgebietsebene zu analysieren. Aus den Ergebnissen der Modellierung lassen sich Handlungsempfehlungen zur Verbesserung der Gewässergüte ableiten. Für die Interpretation der Modellergebnisse sind Kenntnisse über die Genauigkeit und Aussagekraft der Ergebnisse notwendig. Das Modell MONERIS als konzeptionelles Modell für die Anwendung auf Flussgebietsebene wurde innerhalb der vorliegenden Arbeit in 5 europäischen Flusseinzugsgebieten angewandt. Sowohl mit verschiedenen Ansätzen aufbereitete Abflusswerte als auch unterschiedlich hoch aufgelöste Eingangsdaten führten bei der Modellierung zu Änderungen der berechneten Einträge und Frachten. Gezeigt wird, dass mit MONERIS sowohl mittlere Eintrags- und Frachtwerte für eine Periode von mehreren Jahren, als auch Werte für Einzeljahre berechnet werden können. Der Vergleich mit aus Konzentrations- und Abflussmessungen im Gewässer abgeleiteten Frachten wies Abweichungen von <30% auf. Bei der Modellierung von Einzeljahren konnten insbesondere die Jahre mit mittleren Niederschlagsbedingungen gut abgebildet werden. In Jahren mit hohen oder geringen Niederschlägen oder einer außergewöhnlichen Niederschlagsverteilung traten dagegen, bedingt durch die Kalibrierung der meisten Modellkoeffizienten für mittlere Abflussbedingungen von Perioden, Unter- oder Überschätzungen der gemessenen Frachten auf. Monatliche Einträge und Frachten wurden ebenfalls modelliert. Der Vergleich mit Messwerten zeigte hohe Abweichungen, sodass MONERIS für eine monatliche Berechnung noch weiterentwickelt werden muss. Dies betrifft vor allem die Genauigkeit der als Eingangsdaten verwendeten Abflüsse und der Abflusskomponenten sowie den in den Modellversionen vor 2008 verwendeten Retentionsansatz. Auch die räumliche Modellauflösung wurde untersucht und festgestellt, dass eine Modellierung mit MONERIS bis zu einer Auflösung von 1km² problemlos möglich ist. Die Schnittpunkte von Stoffeintragsmodellen mit Modellen aus der Siedlungswasserwirtschaft wurden durch einen Vergleich von MONERIS mit dem Modell STORM in einem stark urban geprägten Einzugsgebiet ermittelt. Obwohl die Unterschiede in den Modellansätzen deutlich wurden, konnte gezeigt werden, dass eine Ergänzung der beiden Modelltypen wünschenswert wäre. Abschließend wird ein neuer Ansatz für die Frachtberechnung aus Abfluss- und Konzentrationsmessungen vorgestellt, durch den die Genauigkeit der berechneten Jahresfrachten bei geringer Anzahl von Messwerten gegenüber etablierten Ansätzen erhöht werden kann. Da die aus Messwerten berechneten Frachten für die Modellkalibrierung und Validierung benötigt werden, kann so auch die Stoffeintragsmodellierung positiv beeinflusst werden.Different models were used to analyse and calculate the amount and origin of the nutrient inputs into riverbasins. Recommended follow-up action can be derived from the model results to improve the river water quality. The interpretation of the modelling results requires the knowledge of the accurateness and the significance of the results. For the investigations, the MONERIS model as a conceptual model was applied in five European river catchments. Different approaches for data preparation as well as a different input data were resulting in a large variation of the calculated nutrient inputs and loads. It was shown, that the MONERIS model is applicable to calculate inputs and loads for periods of several years as well as for one year. In comparison with measured loads mean deviations less than 30% were found. Looking at a yearly timestep, the nutrient inputs and loads in years with mean precipitation conditions were well reproduced. Years with high or low precipitation tends to result in overor underestimation of the nutrient inputs and loads, caused by the calibration of the model coefficients for mean runoff conditions. Monthly inputs and loads were calculated with MONERIS for the first time. The comparison with measured loads shows high deviations. Model improvements have to bee made regarding runoff input values (and runoff components) and retention approach (in the model version before 2008). Furthermore the spatial model resolution was investigated. It could be shown, that the MONERIS model is applicable until a resolution of 1sq.km. In a further application, MONERIS was compared with the urban stormwater management model STORM. Even though there were differences in model approaches, it could be shown a relation between the models for a comprehensive consideration of the calculation of nutrient contamination. Subsequent, a new runoff reduced approach for load calculation based on measurements of runoff and concentrations is presented. This approach allows the calculation of yearly loads with higher precision compared with well-established approaches, if only a low number of concentration measurement is available. The loads calculated from runoff and concentration measurements were important for calibration and validation of nutrient input models and can help to improve there results.
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Kondo, Hanae. "Spatio-temporal properties of membrane-localized actin nucleating complexes." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289704.
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The actin cytoskeleton plays a vital role in various biological processes such as cell migration, morphogenesis, and intracellular trafficking. The polymerization of actin filaments at membranes provides the force for generating dynamic actin structures such as protrusions and invaginations that drive these processes. In filopodia, which are finger-like protrusions comprised of bundled actin filaments, actin regulatory proteins are believed to assemble a distal 'tip complex' which stimulates actin nucleation at the membrane. However how these regulators collectively behave in a macromolecular complex still remains poorly understood. To understand the macromolecular nature of these complexes, I investigated the dynamic properties and spatial organization of actin regulatory factors, using an in vitro reconstitution assay for filopodia-like structures (FLS) utilizing artificial lipid bilayers and Xenopus laevis egg extracts. FRAP analysis of seven actin regulatory factors (Toca-1, N-WASP, GTPase-binding domain, Ena, VASP, Diaph3, Fascin) revealed that the FLS tip complex has both dynamic and stable properties, with different proteins displaying distinct dynamics. Further analyses on the membrane-binding protein Toca-1 showed that its dynamic turnover is controlled by interactions with actin and exchange of molecules with solution. Single-molecule localization microscopy resolved the nanoscale organization of Toca-1, showing its arrangement into flat plaque-like and narrowly elevated tubular substructures. Plaque-like structures showed similarities to phase-transition patterns, while tubule-like structures closely resembled those previously found to decorate membrane tubules in vitro, which are thought to be involved in endocytic membrane remodeling. Endocytic accessory proteins such as SNX9 and Dynamin2 were also found to localize to FLS tips. This work provides new insights into the dynamics and organization of protein ensembles at actin nucleation sites, and proposes a novel link between endocytosis and filopodia formation, which is relevant to understanding how cells decide when and where to assemble actin at the membrane.
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Nagahara, Shizue. "Studies on Functional Magnetic Resonance Imaging with Higher Spatial and Temporal Resolutions." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188540.
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Akamine, Welington Yorihiko Lima. "On the performance of video quality assessment methods for different spatial and temporal resolutions." reponame:Repositório Institucional da UnB, 2017. http://repositorio.unb.br/handle/10482/23490.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2017.Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2017-04-19T18:06:55Z No. of bitstreams: 1 2017_WelingtonYorihikoLimaAkamine.pdf: 87404899 bytes, checksum: 3aed6455d3f98ac54718837d13b92290 (MD5)
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O consumo de vídeos digitais cresce a cada ano. Vários países já utilizam TV digital e o tráfego de dados de vídeos na internet equivale a mais de 60\% de todo o tráfego de dados na internet. Esse aumento no consumo de vídeos digitais exige métodos computacionais viáveis para o cálculo da qualidade do vídeo. Métodos objetivos de qualidade de vídeo são algoritmos que calculam a qualidade do vídeo. As mais recentes métricas de qualidade de vídeo, apesar de adequadas possuem um tempo de execução alto. Em geral, os algoritmos utilizados são complexos e extraem características espaciais e temporais dos vídeos. Neste trabalho, realizamos uma análise dos efeitos da redução da resolução espacial no desempenho dos métodos de avaliação da qualidade do vídeo. Com base nesta análise, nós propomos um framework, para a avaliação da qualidade de vídeo que melhora o tempo de execução das métricas objetivas de qualidade de vídeo sem reduzir o desempenho na predição da qualidade do vídeo. O framework consiste em quatro etapas. A primeira etapa, classificação, identifica os vídeos mais sensíveis à redução da resolução espacial. A segunda etapa, redução, reduz a resolução espacial do vídeo de acordo com a distorção presente. A terceira etapa, predição de qualidade, utiliza uma métrica objetiva para obter uma estimativa da qualidade do vídeo. Finalmente, a quarta etapa realiza um ajuste dos índices de qualidade preditos. Dois classificadores de vídeo são propostos para a etapa de classificação do framework. O primeiro é um classificador com referência, que realiza medidas da atividade espacial dos vídeos. O segundo é um classificador sem-referência, que realiza medidas de entropia espacial e espectral, utilizando Support Vector Machine, para classificar os vídeos. Os classificadores de vídeo têm o objetivo de selecionar o melhor fator de redução da resolução espacial do vídeo. Testamos o framework proposto com 6 métricas objetivas de qualidade de vídeo e 4 bancos de qualidade de vídeo. Com isso, melhoramos o tempo de execução de todas as métricas de qualidade de vídeo testadas.
The consumption of digital videos increases every year. In addition to the fact that many countries already use digital TV, currently the traffic of internet video services are more than 60\% of the total internet traffic. The growth of digital video consumption demands a viable method to measure the video quality. Objective video quality assessment methods are algorithms that estimates video quality. Recent quality assessment methods provide quality predictions that are well correlated with the subjective quality scores. However, most of these methods are very complex and takes long periods to compute. In this work, we analyze the effects of reducing the video spatial resolution on the performance of video quality assessment methods. Based on this analysis, we propose a framework for video quality assessment that reduces the runtime performance of a given video quality assessment method without reducing its accuracy performance. The proposed framework is composed of four stages. The first stage, classification, identifies videos that are more sensitive to spatial resolution reduction. The second stage, reduction, aims to reduce the video spatial resolution according to the video distortion. The third stage, quality prediction, estimates the video quality using an objective video quality assessment method. Finally, the fourth stage normalizes the predicted quality scores according to the video spatial resolution. We design two video classifiers for the first stage of the framework. The first classifier is a full-reference classifier based on a video spatial activity measure. The second is a no-reference classifier based on spatial and spectral entropy measures, which uses a Support Vector Machine (SVM) algorithm. We use the video classifiers to identify the type of distortion in the video and choose the most appropriate spatial resolution. We test the framework using six different video quality assessment methods and four different video quality databases. Results show that the proposed framework improves the average runtime performance of all video quality assessment methods tested. We also analyze the effects of a temporal resolution reduction on the performance of video quality assessment methods. The analysis shows that video quality assessment methods based on temporal features are more sensitive to temporal resolution reduction. Also, videos with temporal distortions, like packet loss, are very sensitive to temporal resolution reduction.
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Ogden, Samuel R. "Automatic Content-Based Temporal Alignment of Image Sequences with Varying Spatio-Temporal Resolution." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3303.
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Many applications use multiple cameras to simultaneously capture imagery of a scene from different vantage points on a rigid, moving camera system over time. Multiple cameras often provide unique viewing angles but also additional levels of detail of a scene at different spatio-temporal resolutions. However, in order to benefit from this added information the sources must be temporally aligned. As a result of cost and physical limitations it is often impractical to synchronize these sources via an external clock device. Most methods attempt synchronization through the recovery of a constant scale factor and offset with respect to time. This limits the generality of such alignment solutions. We present an unsupervised method that utilizes a content-based clustering mechanism in order to temporally align multiple non-synchronized image sequences of different and varying spatio-temporal resolutions. We show that the use of temporal constraints and dynamic programming adds robustness to changes in capture rates, field of view, and resolution.
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Leroux, Shawn. "Constant and temporally variable spatial subsidies and the strength of trophic cascades." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95157.
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Natural ecosystems are open to flows of energy, materials, and organisms. These subsidies are ubiquitous and influence ecosystem structure and functioning at local and regional extents. Subsidized consumers can attain higher biomass and abundance than unsubsidized consumers but the indirect, cascading effects generated from subsidized consumers are not well understood. I derive ecosystem models to investigate the relationship between subsidies and trophic cascades. I show that the ratio of subsidy to equivalent in situ prey may not be the best predictor of consumer response to subsidies, particularly when subsidies are temporally variable. I predict strong generalist consumer responses to subsidies in ecosystems with high in situ prey and relatively frequent subsidies. Next, I use response ratios to quantify the relative effect of predator regulation of herbivores and consumer-mediated recycling on producers stocks. I observe that predator regulation of herbivores has a larger, positive, effect on producer stocks than consumer-mediated recycling, however, consumer-mediated recycling can influence producer biomass in many cases. The relative contribution of both mechanisms to cascading trophic interactions depends on feeding relationships between predator and prey, nutrient turnover rates and the rate of external nutrient loading. Trophic cascade theory and experiments to date, have been conducted in closed ecosystems but recent evidence suggests that predators can have cascading effects across ecosystem boundaries. I derive a model of a recipient ecosystem and demonstrate that ecosystems with higher rates of constant subsidies experience stronger trophic cascades because these subsidies facilitate higher secondary production and consumption. I extend this previous model to meta-ecosystem extents in order to consider the effects of reciprocal pulsed subsidies on ecosystem functioning. I show that reciprocal pulsed subsidies can be reinforcing, particularly when thLes écosystèmes naturels sont ouverts aux flux d'énergie, de matière, et d'organismes. Omniprésents, ces apports allochtones ont un impact sur la structure et le fonctionnement des écosystèmes. S'il est clair que des consommateurs bénéficient directement de ces flux, nous n'avons qu'une connaissance rudimentaire de leurs effets indirects sur les réseaux trophiques. Je développe des modèles d'écosystème afin d'étudier la relation existante entre flux de matière et d'organismes et cascades trophiques. Je démontre ainsi que le ratio de la biomasse des apports sur la biomasse de proie locale ne prédit pas l'effet des flux sur les consommateurs, notamment lorsque ces apports sont variables dans le temps. L'impact des flux sur la biomasse de consommateur se révèle d'autant plus grand quand la biomasse de proie locale est importante et que les flux sont fréquent. J'examine ensuite l'impact relatif du contrôle des herbivores et du recyclage de nutriments par les prédateurs sur la population de plantes et montre que, bien que les deux soient positifs, l'effet du contrôle des herbivores est plus fort. La contribution relative de ces deux mécanismes pour les cascades trophiques dépend des interactions entres proies et prédateurs, des taux de recyclages et des flux de nutriments provenant de l'extérieur. Les cascades trophiques sont généralement étudiées et conceptualisées dans des écosystèmes fermés. Cependant, il a récemment été mis en évidence que les prédateurs peuvent avoir des effets indirects dépassant les frontières d'un écosystème. A l'aide d'un modèle d'écosystème bénéficiant de flux allochtones, je démontre en effet que les cascades trophiques sont d'autant plus fortes quand les écosystèmes reçoivent des flux de matière et d'organismes fréquents. Ce modèle est ensuite étendu à l'échelle de méta-écosystèmes afin d'examiner l'effet des flux réciproques et variables dans le temps sur la force des cascade
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Doudagiri, Vivek Reddy. "Extracting Temporally-Anchored Knowledge from Tweets." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157588/.
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Twitter has quickly become one of the most popular social media sites. It has 313 million monthly active users, and 500 million tweets are published daily. With the massive number of tweets, Twitter users share information about a location along with the temporal awareness. In this work, I focus on tweets where author of the tweets exclusively mentions a location in the tweet. Natural language processing systems can leverage wide range of information from the tweets to build applications like recommender systems that predict the location of the author. This kind of system can be used to increase the visibility of the targeted audience and can also provide recommendations interesting places to visit, hotels to stay, restaurants to eat, targeted on-line advertising, and co-traveler matching based on the temporal information extracted from a tweet. In this work I determine if the author of the tweet is present in the mentioned location of the tweet. I also determine if the author is present in the location before tweeting, while tweeting, or after tweeting. I introduce 5 temporal tags (before the tweet but > 24 hours; before the tweet but < 24 hours; during the tweet is posted; after the tweet is posted but < 24 hours; and after the tweet is posted but > 24 hours). The major contributions of this paper are: (1) creation of a corpus of 1062 tweets containing 1200 location named entities, containing annotations whether author of a tweet is or is not located in the location he tweets about with respect to 5 temporal tags; (2) detailed corpus analysis including real annotation examples and label distributions per temporal tag; (3) detailed inter-annotator agreements, including Cohen's kappa, Krippendorff's alpha and confusion matrices per temporal tag; (4) label distributions and analysis; and (5) supervised learning experiments, along with the results.