To see the other types of publications on this topic, follow the link: Fin rays.
Dissertations / Theses on the topic 'Fin rays'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Fin rays.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Abell, Nicholas. "Population Demographics, Connectivity, and Recruitment Sources of Spotted Bass in Smithland Pool of the Ohio River." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2224.
Full textAbstract:
Understanding spatial patterns in population demographics and the principal natal environments supporting riverine fish populations are important for fisheries management. Although the black basses are among the most popular groups of game fishes in North America, relatively little information exists regarding demographics and environmental history of spotted bass Micropterus punctulatus in riverine environments. Fin ray microchemistry was used to identify natal environment and age estimates from sectioned fin rays used to estimate growth and mortality rates for spotted bass in Smithland pool of the Ohio River and three tributaries. Spotted bass were collected from 2014-2016 in headwater reaches of tributaries using electrofishing, angling, and a seine net, while electrofishing was used exclusively in the Ohio River and lower tributary reaches. Spotted bass in the Ohio River generally lived longer and grew larger than conspecifics in tributaries, although mortality rates were not definitively different. Differences in water Sr:Ca and Ba:Ca among the Ohio River and tributaries were reflected in fin rays from age-0 and age-1 fish. Eighteen percent of spotted bass ≥ age-2 captured in the Ohio River originated in tributaries, whereas 15% captured in tributaries originated in the Ohio River. Although most fish remained in their natal environment, small tributaries can be a supplemental recruitment source for spotted bass populations and fisheries in large rivers. This study highlights the utility of fin rays for microchemical analysis and age estimation of spotted bass.
2
Veinott, G. "Elemental concentrations in the fin rays of white sturgeon, Acipenser transmontanus, by laser ablation sampling-inductively coupled plasma-mass spectrometry (LAS-ICP-MS)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq40492.pdf.
Full text
3
Heide, Jakob, and Patrik Lans. "CFD investigation of a fin keel." Thesis, KTH, Mekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-148816.
Full textAbstract:
This thesis aims to help sailboat owners to decide a preferable NACA profile. A CFD comparison in terms of drag and lift coefficients between two NACA profiles have been applied on a typical fin keel. Each profile has been computed with different angles of attack to investigate the impact of small direction changes. ANSYS Fluent 13.0 is used to model the flow according to RANS k-epsilon model. The conclusion is that NACA65 series gives lower drag while NACA64 series gives higher lift.<br>Syftet med det här examensarbetet är att undersöka skillnaderna för olika NACA-kölprofiler med avseende på tryckkoefficienter Arbetet strävar även efter att ge båtägare en tydligare bild av en fördelaktig NACA-profil. Varje kölprofil har beräknats med olika anfallsvinklar för att undersöka effekten av små vinkeländringar. ANSYS Fluent 13.0 har använts för att modellera flödet enligt k-epsilon-modellen. Slutsatsen är NACA65-serien ger en lägre motståndskoefficient medan NACA64-serien ger en högre lyftkoefficient.
4
Pfaff, Ondřej. "Aplikace Fin Ray principu pro automatizaci výrobních procesů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228903.
Full textAbstract:
This dissertation is about manipulating equipments using Fin Ray Effect ®. The model of manipulator, using this principle, was created for description of the manipulator movement. The measurement was done with this model. After result evaluation the improvement of model was proposed. There were also proposed technical applications where this type of manipulation could be used.
5
Smith, Kurt Thomas. "Evaluation of fin ray and fin spine chemistry as indicators of environmental history for five fish species." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/261.
Full textAbstract:
Knowledge of environmental history is important for the management and conservation of fish populations. Multiple methods to tag or mark fish have been developed (e.g., radio transmitters, coded wire tags, PIT tags, genetic markers), however, each of these methods has limitations. Naturally occurring and artificial chemical markers in otoliths have recently been used to determine natal origins and environmental history of fishes in both marine and freshwater environments and are not subject to the shortcomings of conventional tagging methods. However, few studies have evaluated the application of fish fin rays as a non-lethal alternative to fish otoliths as a recorder of individual fish environmental history. Therefore, I evaluated the application of artificial and naturally occurring chemical markers in fish fin rays as tracers of individual environmental histories. Specifically, I sought to determine 1) if age-0 lake sturgeon pectoral fin rays could be marked by immersion in strontium carbonate (SrCO3) enriched with the stable isotope 86Sr (86SrCO3), 2) whether natural differences in otolith and fin spine chemistry are present in catfish species collected from the Mississippi River basin, and 3) whether natural differences in fin ray chemistry are present in smallmouth bass from different rivers and streams in northern Illinois. Results from the first objective indicated that age-0 lake sturgeon were marked with 83% success when reared in water enriched with 100 µg/L of 86SrCO3, compared to control fish, and mark retention was maintained for at least 120 d following the labeling period. Results of the second objective indicated that both catfish otolith Sr:Ca, δ18O, and δ13C and fin spine Sr:Ca differed among sites, reflecting geographic differences in water chemistry at source locations. Both structures classified fish to their environment of capture with a high degree of accuracy, except in the Middle and Lower Mississippi Rivers where many recent immigrants appeared to be present. Similarly, smallmouth bass fin ray core Sr:Ca differed among sites, reflecting previously documented differences in water chemistry among streams and rivers in northern Illinois. Classification accuracy of smallmouth bass to their environment of capture based on fin ray Sr:Ca was variable, as some rivers had similar water chemistry signatures. The use of artificial chemical marks in fin rays will be useful when marking small fish that may not respond well to physical tags, when non-lethal recovery is desirable, and to distinguish between multiple batches of stocked fish (i.e. to evaluate factors such as stocking location and timing, fish size, and when fish may become interspersed into the existing population). Natural chemical signatures in pectoral fin rays or fin spines may provide a non-lethal alternative to otoliths for gathering information on environmental history (e.g. stock mixing, recruitment sources) of smallmouth bass and catfishes, consistent with recent demonstrations of this technique's effectiveness in other fish species. Ultimately, the use of artificial and naturally occurring chemical marks in fish fin rays provides a non-lethal alternative method to evaluate the environmental history of all life stages of fish
6
Zhang, Jing. "Role of hedgehog signaling in branching morphogenesis and patterning of the fin ray during zebrafish fin regeneration." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27434.
Full textAbstract:
Zebrafish have the capability to regenerate their fins after injury. Previous studies from our laboratory showed that fin regeneration triggers the re-expression of genes involved in the hedgehog (hh) signaling pathway. One member of the hh family, sonic hedgehog (shh) was suggested to regulate bone patterning based on its expgression pattern and functional analysis. Another member of the hh family, Indian hedgehog (ihha) is expressed in the differentiating scleroblasts, the bone-matrix releasing cells, of each fin ray, and may have a more direct role on bone formation based on its expression pattern and known function in other vertebrates. The present study is aimed at investigating the role of hh signalling in patterning the fin ray regenerate and more specifically its role in ray branching morphogenesis. In a first approach, we used the zebrafish 2.2shh:gfp:ABC transgenic line, in which GFP expression recapitulates the endogenous expression of shh, to ablate the shh-expressing cells using a laser beam. Results show that such ablation leads to a delay of ray bifurcation suggesting that the shh-expressing cells play an important role in branching morphogenesis. In a second approach, we cloned the zebrafish hedgehog interacting protein (hip), a hedgehog antagonist, to investigate the effects of its overexpression on ray patterning. Analysis of hip expression during fin regeneration suggests its involvement in limiting hh signaling on the lateral sides of the dermal bones and in their medial region during branching morphogenesis. Overexpression of hip via in vivo cell transfection in the regenerating fin causes a branching delay, possibly as a result of the altered expression of patched1, the hh receptor and type X collagen, a component of the fin ray. These results suggest that hh signaling is involved in patterning the ray branching during zebrafish fin regeneration. Based on the distinct role of shh and ihha suggested by studies in other systems, ihha may be more involved in the scleroblast proliferation and differentiation, and shh is likely to be responsible to pattern the bone formation by directing the site of scleroblast differentiation or possibly mediating scleroblast migration.
7
Debicella, Jaclyn M. "Accuracy and precision of fin-ray aging for gag (Mycteroperca microlepis)." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010802.
Full text
8
Giovacchini, Francesca <1978>. "Cosmic rays anti-deuteron flux sensitivity of the AMS-02 detector." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/335/.
Full text
9
Pratsch, Christoph. "New methods for high resolution 3D imaging with X-rays." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19238.
Full textAbstract:
In der Arbeit haben wir die Grenzen der weit verbreiteten tomographischen
Rekonstruktion von 3D-Proben mittels Transmissionsröntgenmikroskopie charakterisiert.
Wir zeigen, dass die 3D-Auflösung mit diesem Ansatz durch die Schärfentiefe
begrenzt ist. Zur Untersuchung von Alternativen führten wir Simulationen
zur Bildentstehung in einem konfokalen Röntgenmikroskop und einem FIB-SXM
durch. Wir zeigen, dass FIB-SXM ein vielversprechender Ansatz ist, der eine isotrope
3D-Aulösung um die 10 nm erreichen kann und zusätzlich ein drastisch
verbessertes Signal-Rausch-Verhältnis bieten könnte. Wir stellen auch eine neue
Holographiemethode vor, die sich für Vollfeldabbildungen mit kurzen kohärenten
Röntgenpulsen als vorteilhaft erweisen und neue Einsichten in die ultraschnelle
Physik liefern könnte.<br>We have characterized the limitations of the most powerful and
widely used 3D X-ray imaging approach, transmission X-ray microscopy with tomographic
reconstruction. We show that 3D resolution in this approach is limited
by the depth of field. To investigate alternatives, we perform simulations of a
confocal transmission X-ray microscope and a FIB-SXM. We show that FIB-SXM
is a very promising approach that could o er 3D isotropic resolution at 10 nm
with dramatically improved signal to noise. We also introduce a new holography
method that could prove bene cial for full eld imaging with short coherent X-ray
pulses and yield new insights into ultrafast physics.
10
Baud, Amelie. "Fine-mapping complex traits in heterogeneous stock rats." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c762c1af-c899-478f-93e1-305775d5a6f4.
Full textAbstract:
The fundamental theme my thesis explores is the relationship between genetic variation and phenotypic variation. It addresses three main questions. What is the genetic architecture of traits in the HS? How can sequence information help identifying the sequence variants and genes responsible for phenotypic variation? Are the genetic factors contributing to phenotypic variation in the rat homologous to those contributing to variation in the same phenotype in the mouse? To address these questions, I analysed data collected by the EURATRANS consortium on 1,407 Heterogeneous Stock (HS) rats descended from eight inbred strains through sixty generations of outbreeding. The HS rats were genotyped at 803,485 SNPs and 160 measures relevant to a number of models of disease (e.g. anxiety, type 2 diabetes, multiple sclerosis) were collected. The eight founders of the Stock were genotyped and sequenced. I identified loci in the genome that contribute to phenotypic variation (Quantitative Trait Loci, QTLs), and integrated sequence information with the mapping results to identify the genetic variants underlying the QTLs. I made some important observations about the nature of genetic architecture in rats, and how this compares to mice and humans. I also showed how sequence information can be used to improve mapping resolution, and in some cases to identify causal variants. However, I report an unexpected observation: at the majority of QTLs, the genetic effect cannot be accounted for by a single variant. This finding suggests that genetic variation cannot be reduced to sequence variation. This complexity will need to be taken into account by studies that aim at unravelling the genetic basis of complex traits.
11
Quigley, Hailey. "The Role of 5’ hox13 Genes in Danio rerio (Zebrafish) Caudal Fin Ray/Joint Development and Regeneration." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42027.
Full textAbstract:
Zebrafish are part of the teleost infraclass (bony fish) of the ray-finned fish. Like other teleosts, zebrafish possess the ability to regenerate most tissues, including their fins. Zebrafish fins contain segmented bony fin rays that longitudinally span the fin. The segments of fin ray are separated by fibrous joints at regularly spaced intervals providing segmentation and flexibility for the fin. Based on gene expression and changes in cell morphology, joint cell differentiation during development and regeneration proceeds through three stages: presumptive joint, joint-forming, and mature joint cells. Our lab has shown that new joint formation correlates with the upregulation of 5’ hoxa gene, hoxa13a. The hox genes encode transcription factors important for patterning in development. In mice, phenotypes resulting from loss- and gain-of-function mutations in Hox genes have revealed that the spatiotemporal expression of these genes is critical for the correct morphogenesis of the limb, a homologous structure to the fin. The first experiments in this thesis use the NTR/MTZ mechanism to partially ablate hoxa13a-expressing cells in the joints and blastema of the regenerating caudal fin. Partial ablation of the hoxa13a-expressing cells results in shorter bone segments following regeneration of the fin. This experiment draws the conclusion that hoxa13a-expressing cells are involved in the regulation of segment length. To examine the function of the 5’ hoxa/d genes in zebrafish, our lab created CRISPR/Cas9 mutations that inactivate hoxa13a, hoxa13b, and hoxd13a. The triple mutants created through serial breeding, show fin-specific defects in the formation and patterning of joints, as well as general defects in the morphology of the ray and in the actinotrichia, collagenous fibres found at the distal edge of the fin. Overall, our data suggest that hox13 genes are necessary for joint formation and proper fin ray growth. With further phenotypic and genotypic analyses our lab proposes that the dosage of hox13 alleles is responsible for anomalies in fin ray formation found in hox13 mutants.
12
Poiarkova, Anna V. "X-ray absorption fine structure Debye-Waller factors /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/9731.
Full text
13
Preghenella, Roberto <1980>. "The Time-Of-Flight detector of ALICE at LHC: construction, test and commissioning with cosmic rays." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1373/.
Full textAbstract:
The Time-Of-Flight (TOF) detector of ALICE is designed to identify charged particles produced in Pb--Pb collisions at the LHC to address the physics of strongly-interacting matter and the Quark-Gluon Plasma (QGP). The detector is based on the Multigap Resistive Plate Chamber (MRPC) technology which guarantees the excellent performance required for a large time-of-flight array. The construction and installation of the apparatus in the experimental site have been completed and the detector is presently fully operative. All the steps which led to the construction of the TOF detector were strictly followed by a set of quality assurance procedures to enable high and uniform performance and eventually the detector has been commissioned with cosmic rays. This work aims at giving a detailed overview of the ALICE TOF detector, also focusing on the tests performed during the construction phase. The first data-taking experience and the first results obtained with cosmic rays during the commissioning phase are presented as well and allow to confirm the readiness state of the TOF detector for LHC collisions.<br>Il rivelatore Time-Of-Flight (TOF) di ALICE (A Large Ion Collider Experiment) è progettato per l'identificazione delle particelle cariche prodotte nelle collisioni nucleari di LHC (Large Hadron Collider) allo scopo di studiare la fisica della materia fortemente interagente ed il Quark-Gluon Plasma (QGP). Il rivelatore sfrutta la tecnologia innovativa MRPC (Multigap Resistive Plate Chamber) che garantisce le eccellenti prestazioni richieste ad un vasto sistema per la misura del tempo di volo. La costruzione e l'installazione dell'apparato nel sito sperimentale sono state completate ed il rivelatore è attualmente operativo in tutte le sue parti. Tutti i passi necessari per la costruzione del rivelatore finale sono stati accompagnati da una serie di procedure per il controllo della qualità della produzione allo scopo di garantire prestazioni elevate ed uniformi; infine il corretto funzionamento del rivelatore è stato verificato con raggi cosmici.
Questo resoconto ha lo scopo di fornire una visione d'insieme dettagliata del rivelatore TOF di ALICE, focalizzando l'attenzione anche sui test effettuati durante le fasi di costruzione. Oltre ad una breve descrizione dell'esperienza acquisita nelle prime fasi di presa dati sono presentati i primi risultati ottenuti con raggi cosmici che confermano promettenti prestazioni del rivelatore TOF per lo studio delle collisioni di LHC.
14
Tweedle, Valerie. "Simulation Model of Ray Patterning in Zebrafish Caudal Fins." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23181.
Full textAbstract:
The bony fin rays of the zebrafish caudal fin are a convenient system for studying bone morphogenesis and patterning. Joints and bifurcations in fin rays follow predictable spatial patterns, though the mechanisms underlying these patterns are not well understood. We developed simulation models to explore ray pattern formation mechanisms in growing fins. In all models, the fin ray growth rates are based on quantitative experimental data. The different models simulate ray joint formation and bifurcation formation using different hypothetical mechanisms. In the most plausible model, ray joint and bifurcation formation result from the accumulation of two substances, arbitrarily named J and B. Model parameters were optimized to find the best fit between model output and quantitative experimental data on fin ray patterns. The model will be tested in the future by evaluating how well it can predict fin ray patterns in different fin shapes, mutant zebrafish fins, and other fish species.
15
Rosen, Gregory Todd. "X-ray Absorption Fine Spectroscopy of Amorphous Selenium Nanowires." Ohio University Honors Tutorial College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1294448896.
Full text
16
Nievelstein, Hubert Nicolas Maria Willem. "Hemodynamic effects of antihypertensive drugs in conscious spontaneously hypertensive rats." Maastricht : Maastricht : Rijksuniversiteit Limburg ; University Library, Maastricht University [Host], 1987. http://arno.unimaas.nl/show.cgi?fid=5367.
Full text
17
Buades, Bárbara. "Attosecond X-ray absorption fine-structure spectroscopy in condensed matter." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/663092.
Full textAbstract:
Attoscience aims to study electron dynamics in matter with unprecedented temporal resolution by using the shortest pulses generated on Earth. Currently, such resolution is only provided by sources that deliver attosecond pulses based on the high-harmonic generation (HHG) process. In this thesis we make use of the demonstration of the generation of isolated attosecond pulses in the soft X-ray (SXR) regime covering the entire water window (284 eV to 543 eV) with pulse durations shorter than 300 as. Such a source is used to explore its own development, the spectroscopic capabilities of the pulses as well as the spectroscopic differences from existing X-ray sources, and finally to exploit the potential of the provided extraordinary temporal resolution.
We report on the ability to spectrally tune our source 150 eV across the water window by controlling the pressure during the HHG process and the HHG target position with respect to the focal plane of the driving laser pulse. We associate the changes in pressure and target position to a phase matching change between the driving laser pulse of the HHG process and the generated SXR radiation that is mainly caused by a change in the ionisation fraction. These phase matching changes are also compared to a carrier-to-envelope phase changes of the driving laser field.
The attosecond SXR source is used for X-ray absorption fine structure (XAFS) spectroscopy. Our XAFS studies enable the simultaneous probing of extended XAFS (EXFAS) and near edge XAFS (NEXAFS) in graphite, providing element specificity and orbital sensitivity with identification of the sigma* and pi* orbitals in synchronicity with the material’s four characteristic bonding distances. This illustrates the potential capability of correlating electron dynamics with structural dynamics with attosecond resolution being able to resolve charge migration, electron-phonon coupling and structural transitions. Our XAFS investigations also reveal spectral changes in graphite and TiS2 as a consequence of the shorter attosecond pulse compared to the longer picosecond pulse that are typically used in synchrotron facilities. An extended theory is still required to link Auger electron spectroscopy, total electron yield and XAFS using synchrotron radiation with attoXAFS to decouple the different electron dynamics involved on each of the measurements.
Finally, the attosecond pulses are employed to interrogate charge dynamics with unprecedented temporal resolution inside a compound quasi-2D material, TiS2. By synchronising a 1.85 µm pump pulse with the probing attosecond SXR pulse, we observe that the shape of the X-ray absorption line changes from a Lorentzian distribution to a Fano-type distribution oscillating with twice the pump electric field frequency. The absorption changes appear due to an acquired dipole phase response of the photo-excited core-level electron induced by the consecutive arrival of the infrared pump pulse. This demonstrates that field-driven intra-band dynamics dominate over inter-band dynamics. SXR radiation also provides element specificity of attoXAFS which permits, in combination with theory, the visualisation of the flow of charge amongst the atoms inside the unit cell in real time. The combined spatio-temporal capabilities of attosecond transient XAFS may prove decisive to investigate the correlated motion of carriers in quantum materials such as phase-transitions and superconductors.<br>La Attociencia tiene como objetivo estudiar la dinámica de electrones en la materia con una resolución temporal sin precedentes mediante el uso de los pulsos más cortos generados en la Tierra. Actualmente, dicha resolución solo se puede lograr con fuentes de pulsos de attosegundos basados ¿¿en el proceso de generación de armónicos altos (HHG). En esta tesis hacemos uso de la demostración de la generación de pulsos aislados de attosegundos en el régimen de rayos X blandos (SXR) que cubre toda la ventana de agua (284 eV a 543 eV) con duraciones de pulso más cortos que 300 as. Dicha fuente se utiliza para explorar su propio desarrollo, las capacidades espectroscópicas de los pulsos, así como las diferencias espectroscópicas con las fuentes de rayos X existentes, y finalmente explotar el potencial de la resolución temporal extraordinaria proporcionada. Presentamos primero la capacidad de ajustar espectralmente nuestra fuente 150 eV a lo largo de la ventana de agua mediante el control de la presión del gas atómico involucrado en el proceso de HHG y de la posición del proceso de HHG con respecto al plano focal del láser impulsor de activación del proceso. Asociamos los cambios en la presión y en la posición a un cambio de coincidencia de fase entre el láser impulsor y la radiación SXR generada que es causada principalmente por un cambio en la fracción de ionización. Estos cambios de fase también se comparan con los cambios de fase entre la envolvente del campo y el campo (CEP). La fuente de SXR de attosegundo se utiliza para la espectroscopía de estructura fina de absorción de rayos X (XAFS). Nuestros estudios XAFS permiten el sondeo simultáneo de XAFS extendido (EXFAS) y XAFS cercano al borde (NEXAFS) en grafito, proporcionando especificidad de elemento y sensibilidad orbital con identificación de los orbitales sigma* y pi* en sincronicidad con las cuatro distancias de enlace características del material. Esto ilustra la capacidad potencial de correlacionar la dinámica de electrones con la dinámica estructural con resolución de attosegundos, pudiendo resolver la migración de carga, el acoplamiento electrón-fonón y las transiciones estructurales. Nuestras investigaciones XAFS también revelan cambios espectrales en grafito y TiS2 como consecuencia del pulso de atosegundo más corto en comparación con el pulso de picosegundo más largo que se utilizan normalmente en las instalaciones de sincrotrón. Todavía se requiere una teoría extendida para vincular la espectroscopia electrónica de Auger, el campo total de electrones (TEY) y XAFS utilizando radiación sincrotrón con attoXAFS para desacoplar las diferentes dinámicas electrónicas involucradas en cada una de las mediciones. Finalmente, los pulsos de attosegundo se emplean para analizar la dinámica de carga con una resolución temporal sin precedentes dentro de un material compuesto de cuasi-2D, TiS2. Al sincronizar un pulso de luz de bombeo de 1.85 µm con el pulso SXR de attosegundo, observamos que la línea de absorción de rayos X cambia de una distribución de Lorentzian a una distribución de tipo Fano que oscila con el doble de la frecuencia del campo eléctrico de bombeo. Los cambios de absorción aparecen debido a una respuesta de fase dipolar adquirida del electrón excitado por fotoionicaición por la llegada consecutiva del pulso de bombeo infrarrojo. Con esto se demuestra que las dinámicas dentro de la banda impulsadas por el campo dominan sobre la dinámica entre bandas. La radiación SXR también proporciona especificidad de elemento de attoXAFS que permite, en combinación con la teoría, la visualización del flujo de carga entre los átomos dentro de la celda unitaria en tiempo real. Las capacidades espaciotemporales combinadas del XAFS transitorio de attosegundo pueden ser decisivas para investigar el movimiento correlacionado de portadores en materiales cuánticos, como transiciones de fase y superconductores.
18
Crapper, M. D. "X-ray absorption fine structure of adsorbates on metal surfaces." Thesis, University of Warwick, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377093.
Full text
19
DeRose, Guy Arthur. "X-ray absorption fine structure strain determination in thin films." Case Western Reserve University School of Graduate Studies / OhioLINK, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1060005230.
Full text
20
Shorrosh, Raed Saed. "An x-ray absorption fine structure study of semiconductor nanoclusters." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/30867.
Full text
21
Schoemaker, Regina Geertruida. "Experimental heart failure in rats hemodynamic studies on pathophysiology and therapy /." Maastricht : Maastricht : Datawyse ; University Library, Maastricht University [Host], 1989. http://arno.unimaas.nl/show.cgi?fid=5553.
Full text
22
Parisi, Pietro <1982>. "Multiwavelength studies of hard X-ray selected sources." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3775/.
Full text
23
Donnarumma, Annamaria <1981>. "X-ray and lensing mass estimates in galaxy clusters." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2955/.
Full textAbstract:
In this Thesis we have presented our work on the analysis of galaxy clusters through their X-ray emission and the gravitational lensing effect that they induce. Our research work was mainly finalised to verify and possibly explain the observed mismatch between the galaxy cluster mass distributions estimated through two of the most promising techniques, i.e. the X-ray and the gravitational lensing analyses. Moreover, it is an established evidence that combined, multi-wavelength analyses are extremely effective in addressing and explaining the open issues in astronomy: however, in order to follow this approach, it is crucial to test the reliability and the limitations of the individual analysis techniques. In this Thesis we also assessed the impact of some factors that could affect both the X-ray and the strong lensing analyses.
24
Jans, Linda A. W. "Serotonergic vulnerability experimental studies in rats applying the method of acute tryptophan depletion /." [Maastricht] : Maastricht : Maastricht University ; University Library, Universiteit Maastricht [host], 2008. http://arno.unimaas.nl/show.cgi?fid=10770.
Full text
25
Serriere, Jennifer. "Études fonctionnelles et structurales de protéines rétrovirales, Gag du FIV et Tat du VIH-1, à des fins thérapeutiques et vaccinales." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10167.
Full textAbstract:
Depuis sa découverte il y a plus de 30 ans, le Virus de l’Immunodéficience Humaine est à l’origine d’une importante mortalité dans le monde. De par la difficulté de tester l’efficacité de formulations thérapeutiques et/ou vaccinales directement chez l’homme, des études d’infections modèles du VIH, comme celle du Virus de l’Immunodéficience Féline (FIV), ont été entreprises ces dernières années. Au-delà de son intérêt vétérinaire, l’étude du FIV représente un avantage important pour trouver un moyen de contrôler les infections par les lentivirus tel que le VIH. Elle peut permettre de développer et surtout de tester l’efficacité des vaccins et/ou thérapies spécifiques chez le chat, dont le SIDA mime les symptômes et les modifications hématologiques rencontrés chez l’homme. Ce manuscrit s’est intéressé à l’étude structurale de deux familles de protéines virales de ces virus, les protéines lentivirales précoces (protéine Tat du VIH) et tardives (domaines Capside CA et Matrice MA de Gag du FIV). L’étude structurale de ces protéines et leur compréhension fonctionnelle au sein de l’hôte pourront à l’avenir ouvrir de nouvelles voies thérapeutiques et/ou vaccinales contre les lentivirus, palliant ainsi les problèmes existants de résistances virales<br>Since its discovery 30 years ago, the Human Immunodeficiency Virus is the cause of an important mortality worldwide. Because of the difficulty to test the efficiency of therapeutical and/or vaccinal formulations directly in humans, studies of models of HIV infections, such as the Feline Immunodeficiency Virus (FIV), have been performed in recent years. In addition to its veterinary interest, the study of FIV is an important issue to find a way to control infections by lentiviruses such as HIV. It can help to develop and test the efficiency of specific therapies and/or vaccines for cats, where AIDS mimics the symptoms and hematologic changes observed in humans. This manuscript describes the structural study of two types of viral proteins of these viruses, early lentiviral proteins (HIV Tat protein) and late lentiviral proteins (CA capsid and MA Matrix domains of FIV Gag). The structural study of these proteins and their functional understanding into the host will open new therapeutic and/or vaccine strategies against these lentiviruses in the future, in order to overcome the existing problems of viral resistance
26
Liu, Xiangxin. "Photoluminescence and Extended X-ray Absorption Fine Structure Studies on CdTe Material." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing.), 2006. http://www.ohiolink.edu/etd/view.cgi?toledo1148408018.
Full textAbstract:
Thesis (Ph. D.)--University of Toledo, 2006.<br>Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Physics." Includes bibliographical references (leaves 160-167).
27
Funatsuki, Atsushi. "Development of Forensic Identification Method with X-Ray Absorption Fine Structure Analysis." Kyoto University, 2017. http://hdl.handle.net/2433/228235.
Full text
28
Coumans, Audrey Barbara Catharina. "Endotoxemia effects on the circulation and the brain : studies in fetal sheep and neonatal rats /." [Maastricht : Maastricht : Universiteit Maastricht] ; University Library, Maastricht University [Host], 2003. http://arno.unimaas.nl/show.cgi?fid=6028.
Full text
29
Giustini, Margherita <1983>. "Accretion disk winds in active galactic nuclei: an X-ray view." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3892/.
Full textAbstract:
This Thesis focuses on the X-ray study of the inner regions of Active Galactic
Nuclei, in particular on the formation of high velocity winds by the accretion
disk itself. Constraining AGN winds physical parameters is of paramount
importance both for understanding the physics of the accretion/ejection flow
onto supermassive black holes, and for quantifying the amount of feedback
between the SMBH and its environment across the cosmic time. The sources selected for the present study are BAL, mini-BAL, and NAL QSOs,
known to host high-velocity winds associated to the AGN nuclear regions.
Observationally, a three-fold strategy has been adopted:
- substantial samples of distant sources have been
analyzed through spectral, photometric, and statistical
techniques, to gain insights into their mean properties as a population;
- a moderately sized sample of bright sources has been
studied through detailed X-ray spectral analysis, to give a first
flavor of the general spectral properties of these sources, also from a temporally resolved point of view;
- the best nearby candidate has been thoroughly studied
using the most sophisticated spectral analysis techniques applied to
a large dataset with a high S/N ratio, to understand the details of the physics of its accretion/ejection flow.
There are three main channels through which this Thesis has been developed:
- [Archival Studies]: the XMM-Newton public archival data has been extensively used to analyze both a large sample of distant BAL QSOs, and several individual bright sources, either BAL, mini-BAL, or NAL QSOs.
- [New Observational Campaign]: I proposed and was awarded with new X-ray pointings of the mini-BAL QSOs PG 1126-041 and PG 1351+640 during the XMM-Newton AO-7 and AO-8. These produced the biggest X-ray observational campaign ever made on a mini-BAL QSO (PG 1126-041), including the longest exposure so far. Thanks to the exceptional dataset, a whealth of informations have been obtained on both the intrinsic continuum and on the complex reprocessing media that happen to be in the inner regions of this AGN. Furthermore, the temporally resolved X-ray
spectral analysis field has been finally opened for mini-BAL QSOs.
- [Theoretical Studies]: some issues about the connection between theories and observations of AGN accretion disk winds have been investigated, through theoretical arguments and synthetic absorption line profiles studies.
30
Fioretti, Valentina <1982>. "Background minimization issues for next generation hard X-ray focusing telescopes." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3858/.
Full textAbstract:
The hard X-ray band (10 - 100 keV) has been only observed so far by collimated and coded aperture mask instruments, with a sensitivity and an angular resolution lower than two orders of magnitude as respects the current X-ray focusing telescopes operating below 10 - 15 keV.
The technological advance in X-ray mirrors and detection systems is now able to extend the X-ray focusing technique to the hard X-ray domain, filling the gap in terms of observational performances and providing a totally new deep view on some of the most energetic phenomena of the Universe.
In order to reach a sensitivity of 1 muCrab in the 10 - 40 keV energy range, a great care in the background minimization is required, a common issue for all the hard X-ray focusing telescopes.
In the present PhD thesis, a comprehensive analysis of the space radiation environment, the payload design and the resulting prompt X-ray background level is presented, with the aim of driving the feasibility study of the shielding system and assessing the scientific requirements of the future hard X-ray missions.
A Geant4 based multi-mission background simulator, BoGEMMS, is developed to be applied to any high energy mission for which the shielding and instruments performances are required. It allows to interactively create a virtual model of the telescope and expose it to the space radiation environment, tracking the particles along their path and filtering the simulated background counts as a real observation in space.
Its flexibility is exploited to evaluate the background spectra of the Simbol-X and NHXM mission, as well as the soft proton scattering by the X-ray optics and the selection of the best shielding configuration.
Altough the Simbol-X and NHXM missions are the case studies of the background analysis, the obtained results can be generalized to any future hard X-ray telescope. For this reason, a simplified, ideal payload model is also used to select the major sources of background in LEO.
All the results are original contributions to the assessment studies of the cited missions, as part of the background groups activities.
31
Amidani, Lucia <1985>. "Progress in x-ray spectroscopies for the study of advanced materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5188/.
Full textAbstract:
This thesis work is focused on the use of selected core-level x-ray spectroscopies to study semiconductor materials of great technological interest and on the development of a new implementation of appearance potential spectroscopy.
Core-level spectroscopies can be exploited to study these materials with a local approach since they are sensitive to the electronic structure localized on a chemical species present in the sample examined. This approach, in fact, provides important micro-structural information that is difficult to obtain with techniques sensitive to the average properties of materials.
In this thesis work we present a novel approach to the study of semiconductors with core-level spectroscopies based on an original analysis procedure that leads to an insightful understanding of the correlation between the local micro-structure and the spectral features observed. In particular, we studied the micro-structure of Hydrogen induced defects in nitride semiconductors, since the analysed materials show substantial variations of optical and electronic properties as a consequence of H incorporation.
Finally, we present a novel implementation of soft x-ray appearance potential spectroscopy, a core-level spectroscopy that uses electrons as a source of excitation and has the great advantage of being an in-house technique. The original set-up illustrated was designed to reach a high signal-to-noise ratio for the acquisition of good quality spectra that can then be analyzed in the framework of the real space full multiple scattering theory. This technique has never been coupled with this analysis approach and therefore our work unite a novel implementation with an original data analysis method, enlarging the field of application of this technique.
32
Giachini, Lisa <1978>. "Structure and dynamics of metal sites in proteins: X-ray Absorption Spectroscopy investigations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/334/.
Full text
33
Andrews, Paul. "In situ studies of homogeneous nickel alkene oligomerisation catalysts." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239603.
Full text
34
Breda, Eric van. "The effect of testosterone on skeletal muscle energy metabolism in diabetic and non-diabetic endurance trained rats." [Maastricht : Maastricht : Rijksuniversiteit Limburg] ; University Library, Maastricht University [Host], 1994. http://arno.unimaas.nl/show.cgi?fid=6588.
Full text
35
Ainsworth, S. "Surface EXAFS (extended X-ray absorption fine structure) studies of adsorbates on surfaces." Thesis, University of Warwick, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377090.
Full text
36
Holt, Steven Denys. "An extended X-ray absorption fine structure study of urea amidohydrolase and rusticyanin." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303575.
Full text
37
Ponti, Gabriele <1977>. "Probing the innermost regions around supermassive black holes through X–ray spectral variability." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/364/.
Full text
38
Behlouli, Abdeslam. "Simulation du canal optique sans fil. Application aux télécommunications optique sans fil." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2308/document.
Full textAbstract:
Le contexte de cette thèse est celui des communications optiques sans fil pour des applications en environnements indoor. Pour discuter des performances d'une liaison optique sans fil, il est nécessaire d'établir une étude caractéristique du comportement du canal de propagation. Cette étude passe par l'étape de la mesure ou de l'estimation par la simulation de la réponse impulsionnelle. Après avoir décrit la composition d'une liaison et passé en revue les méthodes de simulation existantes, nous présentons nos algorithmes de simulation dans des environnements réalistes, en nous intéressant à leurs performances en termes de précision et de temps de calcul. Ces méthodes sont basées sur la résolution des équations de transport de la lumière par du lancer de rayons associées aux méthodes d'intégration stochastique de Monte Carlo. La version classique de ces méthodes est à la base de trois algorithmes de simulations proposés. En utilisant une optimisation par des chaînes de Markov, nous présentons ensuite deux autres algorithmes. Un bilan des performances de ces algorithmes est établi dans des scénarios mono et multi-antennes. Finalement, nous appliquons nos algorithmes pour caractériser l'impact de l'environnement de simulation sur les performances d'une liaison de communication par lumière visible, à savoir les modèles d'émetteurs, les matériaux des surfaces, l'obstruction du corps de l'utilisateur et sa mobilité, et la géométrie de la scène de simulation<br>The context of this PhD thesis falls within the scope of optical wireless communications for applications in indoor environments. To discuss the performance of an optical wireless link, it is necessary to establish a characteristic study of the behavior of the optical wave propagation channel. This study can be realized by measurement or by the simulation of the channel impulse response. After describing the composition of an optical wireless link and reviewing existing simulation methods, we present our new simulation algorithms channel in realistic environments by focusing on their performances in terms of accuracy and their complexity in terms of computation time. These methods are based on solving the light transport equations by ray-tracing techniques associated with stochastic Monte Carlo integration methods. The classical version of these methods is the basis of three proposed simulation algorithms. By applying an optimization using Markov Chain, we present two new algorithms. A performance assessment of our simulation algorithms is established in mono and multi-antenna scenarios of our simulation algorithms. Finally, we present the application of these algorithms for characterizing the impact of the simulation environment on the performances of a visible light communication link. We particularly focus on the transmitter models, surface coating materials, obstruction of the user's body and its mobility, and the geometry of the simulation scene
39
Veronesi, Giulia <1982>. "Advanced applications of X-ray Absorption Spectroscopy to the study of protein metal sites." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2535/.
Full textAbstract:
We present a study of the metal sites of different proteins through X-ray Absorption Fine Structure (XAFS) spectroscopy. First of all, the capabilities of XAFS analysis have been improved by ab initio simulation of the near-edge region of the spectra, and an original analysis method has been proposed. The method subsequently served ad a tool to treat diverse biophysical problems, like the inhibition of proton-translocating proteins by metal ions and the matrix effect exerted on photosynthetic proteins (the bacterial Reaction Center, RC) by strongly dehydrate sugar matrices. A time-resolved study of Fe site of RC with μs resolution has been as well attempted.
Finally, a further step aimed to improve the reliability of XAFS analysis has been performed by calculating the dynamical parameters of the metal binding cluster by means of DFT methods, and the theoretical result obtained for MbCO has been successfully compared with experimental data.
40
Oppen, Claudia Anna Maria Leonardus van. "From rags to richness a structuration perspective on interactional richness and its impact on customer evaluations of online experiences /." [Maastricht : Maastricht : Universiteit Maastricht] ; University Library, Universiteit Maastricht [host], 2007. http://arno.unimaas.nl/show.cgi?fid=8854.
Full text
41
McManus, Moyra Kathleen. "X-ray absorption fine structure measurements of the lattice strain in magnetic ultrathin films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24332.pdf.
Full text
42
Reikowski, Finn [Verfasser]. "In Situ X-ray Scattering Studies of Ultrathin Epitaxial Metal Oxide Films / Finn Reikowski." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1189658763/34.
Full text
43
Torresi, Eleonora <1981>. "The gaseous environment of radio galaxies: a new perspective from high-resolution x-ray spectroscopy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3820/.
Full textAbstract:
It is known that massive black holes have a profound effect on the evolution of galaxies, and possibly on their formation by regulating the amount of gas available for the star formation. However, how black hole and galaxies communicate is still an open problem, depending on how much of the energy released interacts with the circumnuclear matter.
In the last years, most studies of feedback have primarily focused on AGN jet/cavity systems in the most massive galaxy clusters. This thesis intends to investigate the feedback phenomena in radio--loud AGNs from a different perspective studying isolated radio galaxies, through high-resolution spectroscopy. In particular one NLRG and three BLRG are studied, searching for warm gas, both in emission and absorption, in the soft X-ray band. I show that the soft spectrum of 3C33 originates from gas photoionized by the central engine. I found for the first time WA in 3C382 and 3C390.3. I show that the observed warm emitter/absorbers is not uniform and probably located in the NLR.
The detected WA is slow implying a mass outflow rate and kinetic luminosity always well below 1% the L(acc) as well as the P(jet).
Finally the radio--loud properties are compared with those of type 1 RQ AGNs.
A positive correlation is found between the mass outflow rate/kinetic luminosity, and the radio loudness.
This seems to suggest that the presence of a radio source (the jet?) affects the distribution of the absorbing gas.
Alternatively, if the gas distribution is similar in Seyferts and radio galaxies, the M(out) vs rl relation could simply indicate a major ejection of matter in the form of wind in powerful radio AGNs.
44
Morandi, Andrea <1979>. "Properties of gas and dark matter in X-ray galaxy clusters with Sunyaev Zel'dovich measurements." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/633/.
Full textAbstract:
I have studied entropy profiles obtained in a sample of 24 X-ray objects at high
redshift retrieved from the Chandra archive. I have discussed the scaling
properties of the entropy S, the correlation between metallicity Z and S, the
profiles of the temperature of the gas, Tgas, and performed a comparison between the
dark matter 'temperature' and Tgas in order to constrain the non-gravitational
processes which affect the thermal history of the gas. Furthermore I have studied
the scaling relations between the X-ray quantities and Sunyaev Zel'dovich
measurements. I have observed that X-ray laws are steeper than the relations
predicted from the adiabatic model. These deviations from expectations based on
self-similarity are usually interpreted in terms of feedback processes leading to
non-gravitational gas heating, and suggesting a scenario in which the ICM at higher
redshift has lower both X-ray luminosity and pressure in the central regions than
the expectations from self-similar model. I have also investigated a Bayesian X-ray
and Sunyaev Zel'dovich analysis, which allows to study the external regions of the
clusters well beyond the volumes resolved with X-ray observations (1/3-1/2 of the
virial radius), to measure the deprojected physical cluster properties, like
temperature, density, entropy, gas mass and total mass up to the virial radius.
45
Navarro, Valéria Coelho Costa. "Modelo de gerenciamento de risco em radiologia intervencionista para fins regulatórios." Pós-Graduação em Física, 2013. https://ri.ufs.br/handle/riufs/5342.
Full textAbstract:
The number of invasive procedures using interventional radiology has increased
significantly in recent years. This fact is due to several factors, such as the aging
population, the increased of obese population, which has immediate effects on the
number of cancer and vascular diseases, the increased of incidence rate of alcoholism
and hepatitis, which provide increased of cirrhosis, among others. Some medical
specialties use this modality very often, in particular, the angiology, the cardiology, the
hepatology and the neurology. The Interventional Radiology, however, can involve high
doses and long exposure times, being considered currently the radiology practice of
largest medical and occupational exposures, with the possibility of, not only stochastic,
but also deterministic events, such as necrosis, erythema, epilation and cancer. In this
context, the international studies indicate the need to revise the reference levels, to
develop methodologies for dosimetry of patients and staff, including continuously
optimization of dose parameters, such as filtration, collimation and rectification, to
develop quality control tools and training in radiation protection for those involved in
Interventional Radiology. In Brazil, the literature indicated ten publications addressing
this topic, and three deal with the technical aspects of equipment performance, four of
occupational exposures, medical exposures of two and a review general aspects of
interventional radiology. The publications have reported studies that were performed by
evaluating a maximum of two equipment, with results indicating high medical and
occupational exposures, low image quality and the need to implement quality assurance
programs. It is noteworthy that no studies have examined thoroughly the procedure, in
others words, exposures and equipment performances, and they were restricted to one
service. On the other hand, besides the few papers published, there is no specific
legislation on the country, because the Federal Regulation SVS/MS 453/98 only
addresses the general issues of fluoroscopy. Thus, the lack of studies about the reality of
Interventional Radiology procedures, as well as more complete information of the
procedures, require the new studies, especially now that the National Agency of
Sanitary Surveillance - ANVISA is updating the Federal Regulation SVS/MS 453/98.
Then, aiming to help filling a gap of knowledge in Medical Physics in Brazil and at
Brazilian legislation, the objective of this study was to evaluate interventional radiology
services in two states, Bahia and Santa Catarina, to characterize the technologies and
practices used and the risk to patients and workers, proposing technical requirements
and testing protocols, adequate to the actual situation, without losing the perspective of
international standards and recommendations, as well as to develop the of Effective
Potential Risk Assessment Model (EPRAM), a tool for auditing and risk management,
that is an adaptation of a methodology for auditing radiology services, and to validate it
in 20 rooms of interventional radiology procedures of 16 services in two Brazilian
states. The results showed that no services meet the minimum requirements of the law
and, even if some basic and essential requirements for safety were not considered, only
5 (25%) of the rooms were at potential effective risk acceptable<br>O número de procedimentos invasivos utilizando a Radiologia Intervencionista vem
aumentando significativamente nos últimos anos. Este fato é decorrente de vários
fatores, como por exemplo, o envelhecimento da população e o aumento da população
obesa, que tem reflexos imediatos no número de câncer e doenças vasculares, o
aumento no índice de alcoolismo e de hepatite, que proporcionam aumento de cirroses,
entre outros. Algumas especialidades médicas já se apropriaram desta prática, em
especial, a angiologia, a cardiologia, a hepatologia e a neurologia. A Radiologia
Intervencionista, entretanto, pode envolver doses elevadas de radiação e longos tempos
de exposição, sendo considerada, atualmente, a prática radiológica de maiores
exposições médicas e ocupacionais, com a possibilidade de eventos determinísticos,
além dos estocásticos, podendo provocar assim necroses, eritemas, epilação e câncer.
Neste contexto, os estudos e recomendações internacionais apontam para a necessidade
de revisão dos níveis de referência, desenvolvimento de metodologias para dosimetria
de pacientes e equipe, otimização dos fatores que influenciam na dose, a exemplo de
filtração, colimação e retificação, desenvolvimento e aplicação de ferramentas de
controle de qualidade e treinamento em proteção radiológica para os envolvidos em
Radiologia Intervencionista. No Brasil, o levantamento bibliográfico indicou dez
publicações abordando este tema, sendo que, três tratam dos aspectos técnicos relativos
ao desempenho dos equipamentos, quatro de exposições ocupacionais, duas das
exposições médicas e uma revisa aspectos gerais da radiologia intervencionista. Mesmo
as publicações tendo relatado estudos que foram realizados através da avaliação de
alguns equipamentos, os resultados indicam altas exposições ocupacionais e médica,
baixa qualidade da imagem e necessidade de implantação de programas de garantia de
qualidade. Vale ressaltar que nenhum dos estudos avaliou de forma completa o
procedimento, incluindo as questões da legislação vigente, as exposições e o
desempenho do equipamento. Além dos poucos trabalhos publicados, tem-se a
inexistência de legislação específica sobre o tema, pois a Portaria Federal SVS/MS
453/98, aborda apenas as questões gerais de fluoroscopia. Assim, a inexistência de
estudos mais amplos sobre a realidade dos procedimentos de Radiologia
Intervencionista, bem como de informações mais completas dos procedimentos,
demandam a realização de novos estudos, principalmente neste momento em que a
ANVISA, está atualizando a Portaria SVS/MS 453/98, sendo possível que os resultados
dos estudos sejam utilizados com subsídios para aspectos técnicos da nova versão da
norma brasileira. Então, com a perspectiva de contribuir para suprir uma lacuna do
conhecimento na Física Médica brasileira, bem como da legislação, o objetivo deste
trabalho foi avaliar serviços de radiologia intervencionista em dois estados, Bahia e
Santa Catarina, para caracterizar as tecnologias e práticas utilizadas, bem como a
situação de risco para os pacientes e trabalhadores, propondo requisitos técnicos e
protocolos de testes, adequados à realidade encontrada, sem perder a perspectiva dos
padrões e recomendações internacionais, bem como desenvolver o MARPE, uma
ferramenta para auditoria e gerenciamento de risco, a partir da adaptação de uma
metodologia desenvolvida para auditorias de serviços de radiodiagnóstico, validando-a
em 20 salas de procedimentos de radiologia intervencionista de 16 serviços nos dois
estados brasileiro. Os resultados obtidos mostraram que nenhum serviço cumpria os
requisitos mínimos da legislação vigente e mesmo se alguns requisitos básico e
indispensável de segurança, não fossem considerados, apenas 5 (25%) das salas
avaliadas estavam em situação de risco potencial efetivo aceitável
46
Vries, Johannes Erik de. "Genotypic and phenotypic effects of c-Ha-ras oncogene transfection on human colorectal carcinoma cell lines." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1993. http://arno.unimaas.nl/show.cgi?fid=5752.
Full text
47
Vito, Fabio <1986>. "X-ray properties and evolution of high-redshift AGN, and the gas content of host galaxies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6729/.
Full textAbstract:
In this thesis, I have investigated the evolution of the high-redshift (z > 3) AGN population by collecting data from some of the major Chandra and XMM-Newton surveys. The final sample (141 sources) is one of the largest selected at z> 3 in the X- rays and it is characterised by a very high redshift completeness (98%). I derived the spectral slopes and obscurations through a spectral anaysis and I assessed the high-z evolution by deriving the luminosity function and the number counts of the sample. The best representation of the AGN evolution is a pure density evolution (PDE) model: the AGN space density is found to decrease by a factor of 10 from z=3 to z=5. I also found that about 50% of AGN are obscured by large column densities (logNH > 23). By comparing these data with those in the Local Universe, I found a positive evolution of the obscured AGN fraction with redshift, especially for luminous (logLx > 44) AGN. I also studied the gas content of z < 1 AGN-hosting galaxies and compared it with that of inactive galaxies. For the first time, I applied to AGN a method to derive the gas mass previously used for inactive galaxies only. AGN are found to live preferentially in gas-rich galaxies. This result on the one hand can help us in understanding the AGN triggering mechanisms, on the other hand explains why AGN are preferentially hosted by star-forming galaxies.
48
Swaraj, Sufal. "Surface chemical characterization of plasma-chemically deposited polymer films by X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure." [S.l.] : [s.n.], 2005. http://www.diss.fu-berlin.de/2005/273/index.html.
Full text
49
Buchanan, Piers. "The structure of liquid semiconductors, superionic conductors and glasses by neutron scattering, X-ray diffraction and extended X-ray absorption fine structure." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392943.
Full text
50
Gorp, Adrianus Wilhelmus van. "The relationship between structural and in vivo dynamic mechanical properties of the thoracic aorta in rats influence of ageing and hypertension /." Maastricht : Maastricht : Universiteit Maastricht ; University Library, Maastricht University [Host], 1999. http://arno.unimaas.nl/show.cgi?fid=7537.
Full text