To see the other types of publications on this topic, follow the link: Frog with a tail.
Dissertations / Theses on the topic 'Frog with a tail'
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 'Frog with a tail.'
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
Tucker, Abigail Saffron. "Tail development in Xenopus laevis." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297296.
Full text
2
Alexandersson, Ilona. "Comet Ion Tail Observations Far From the Nucleus." Thesis, Uppsala universitet, Institutet för rymdfysik, Uppsalaavdelningen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150106.
Full textAbstract:
On may 1, 1996, Ulysses spacecraft crossed the ion tail of comet Hyakutake, revealing an ion tail length of more than 3 times the Sun-Earth distance. The signatures of an ion tail, especially the ion tail far from the nucleus, are not well explored and many question marks remain. This report summarizes previous observations of spacecraft - ion tail crossings and what signatures that can be expected, as well as signatures of other known solar wind structures. A data analysis is made of possible ion tail encounters from Rosetta spacecraft measurements, Ulysses spacecraft measurements and Earth-orbiting spacecraft measurements. A search from Venus Express data to detect ion tails of sungrazing comets is presented.
3
Leal, Laura Simonsen. "An SDF approach to hedge funds’ tail risk: evidence from Brazilian funds." reponame:Repositório Institucional do FGV, 2016. http://hdl.handle.net/10438/16638.
Full textAbstract:
Submitted by Laura Simonsen Leal (arula@fgvmail.br) on 2016-06-22T12:59:34Z
No. of bitstreams: 1
laura_tese14(final).pdf: 1036208 bytes, checksum: eac8007047195b00593f30884e72a3e2 (MD5)Approved for entry into archive by GILSON ROCHA MIRANDA (gilson.miranda@fgv.br) on 2016-06-22T13:18:16Z (GMT) No. of bitstreams: 1 laura_tese14(final).pdf: 1036208 bytes, checksum: eac8007047195b00593f30884e72a3e2 (MD5)
Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2016-06-29T13:38:50Z (GMT) No. of bitstreams: 1 laura_tese14(final).pdf: 1036208 bytes, checksum: eac8007047195b00593f30884e72a3e2 (MD5)
Made available in DSpace on 2016-06-29T13:39:56Z (GMT). No. of bitstreams: 1 laura_tese14(final).pdf: 1036208 bytes, checksum: eac8007047195b00593f30884e72a3e2 (MD5) Previous issue date: 2016-03-21
The main purpose of this paper is to propose a methodology to obtain a hedge fund tail risk measure. Our measure builds on the methodologies proposed by Almeida and Garcia (2015) and Almeida, Ardison, Garcia, and Vicente (2016), which rely in solving dual minimization problems of Cressie Read discrepancy functions in spaces of probability measures. Due to the recently documented robustness of the Hellinger estimator (Kitamura et al., 2013), we adopt within the Cressie Read family, this specific discrepancy as loss function. From this choice, we derive a minimum Hellinger risk-neutral measure that correctly prices an observed panel of hedge fund returns. The estimated risk-neutral measure is used to construct our tail risk measure by pricing synthetic out-of-the-money put options on hedge fund returns of ten specific categories. We provide a detailed description of our methodology, extract the aggregate Tail risk hedge fund factor for Brazilian funds, and as a by product, a set of individual Tail risk factors for each specific hedge fund category.
4
Johnson, Christopher David. "Characteristics of sympathetic nerve activity recorded from blood vessels of the rat tail." Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267856.
Full text
5
Dailey, Simon Christopher. "Evolutionary developmental and genomic insights from a tail regeneration transcriptome of the cephalochordate Branchiostoma lanceolatum." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12608.
Full text
6
Wu, Sirui. "A study on Extraction of Natural Cities from the Nightlight Imagery Using Head/tail breaks method." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-15767.
Full textAbstract:
With the high development of economic and demand for city research, an issue of detecting city boundaries plays an extremely important role in urbanization that promotes the progress of human civilization. Some critical applications such as land use, urban planning and city sprawl have been constantly discussed, which rely on the acquisition of city areas. For the better acquisition of city areas, choosing a proper method to capture city boundaries becomes significant where it greatly improves the value of city study. Although conventional data can be used to define the city boundaries, some drawbacks still exist when measuring the city boundaries in a global scale. Remote sensing (RS) data of nightlight imagery (2010) by Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS) acquired from National oceanic and atmospheric administration's National Geoscience Data Center (NOAA/NOGA) is applied to extract the city boundaries in fifty countries, of which these countries are chosen followed by the Gross Domestic Product that are ranked in top 50. In this case, the data distribution of nightlight imagery followed by heavy-tailed distribution. Head/tail break algorithm poses a possibility of calculating reasonable threshold and extracting the natural cities with the help of software based on the Geomatics information system (GIS). An extended study of power law is made by using of power law estimator from previous studies to check whether the extracted natural cities can match the power law distribution. Result shows that combination of the nightlight imagery data and the head/tail break is capable of extracting the city boundaries and a set of possible thresholds with visual inspection by using the head/tail break are executed. There is only one country, namely Belgium, cannot be processed due to its data properties. Result also address how well the natural cities of the fifty countries can be extracted in terms of visual inspection, among the chosen cities, 33 of countries boundaries can be better matched and 13 countries can fundamentally match the city boundaries. Meanwhile, an extended study of power law is provided and four countries have to be found that do not follow the power law distribution. From the result obtained, the study expects that integration of support data will efficiently increase the accuracy of extraction and more useful information can be acquired in further study. On the other hand, a comparative study of threshold decision needs to be verified, put it differently, whether using head/tail break with visual inspection on extracted city boundaries is helpful or not.
7
Wigle, Jeffrey T. "Molecular cloning, characterization and expression of a novel family of tail-anchored membrane proteins from the myocardium." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ28383.pdf.
Full text
8
Hernandez, Javiera I. "Does the Pareto Distribution of Hurricane Damage Inherit its Fat Tail from a Zipf Distribution of Assets at Hazard?" FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1488.
Full textAbstract:
Tropical Cyclones are a continuing threat to life and property. Willoughby (2012) found that a Pareto (power-law) cumulative distribution fitted to the most damaging 10% of US hurricane seasons fit their impacts well. Here, we find that damage follows a Pareto distribution because the assets at hazard follow a Zipf distribution, which can be thought of as a Pareto distribution with exponent 1. The Z-CAT model is an idealized hurricane catastrophe model that represents a coastline where populated places with Zipf- distributed assets are randomly scattered and damaged by virtual hurricanes with sizes and intensities generated through a Monte-Carlo process. Results produce realistic Pareto exponents. The ability of the Z-CAT model to simulate different climate scenarios allowed testing of sensitivities to Maximum Potential Intensity, landfall rates and building structure vulnerability. The Z-CAT model results demonstrate that a statistical significant difference in damage is found when only changes in the parameters create a doubling of damage.
9
HUANG, KUAN-YU. "Fractal or Scaling Analysis of Natural Cities Extracted from Open Geographic Data Sources." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-19386.
Full textAbstract:
A city consists of many elements such as humans, buildings, and roads. The complexity of cities is difficult to measure using Euclidean geometry. In this study, we use fractal geometry (scaling analysis) to measure the complexity of urban areas. We observe urban development from different perspectives using the bottom-up approach. In a bottom-up approach, we observe an urban region from a basic to higher level from our daily life perspective to an overall view. Furthermore, an urban environment is not constant, but it is complex; cities with greater complexity are more prosperous. There are many disciplines that analyze changes in the Earth’s surface, such as urban planning, detection of melting ice, and deforestation management. Moreover, these disciplines can take advantage of remote sensing for research. This study not only uses satellite imaging to analyze urban areas but also uses check-in and points of interest (POI) data. It uses straightforward means to observe an urban environment using the bottom-up approach and measure its complexity using fractal geometry. Web 2.0, which has many volunteers who share their information on different platforms, was one of the most important tools in this study. We can easily obtain rough data from various platforms such as the Stanford Large Network Dataset Collection (SLNDC), the Earth Observation Group (EOG), and CloudMade. The check-in data in this thesis were downloaded from SLNDC, the POI data were obtained from CloudMade, and the nighttime lights imaging data were collected from EOG. In this study, we used these three types of data to derive natural cities representing city regions using a bottom-up approach. Natural cities were derived from open geographic data without human manipulation. After refining data, we used rough data to derive natural cities. This study used a triangulated irregular network to derive natural cities from check-in and POI data. In this study, we focus on the four largest US natural cities regions: Chicago, New York, San Francisco, and Los Angeles. The result is that the New York City region is the most complex area in the United States. Box-counting fractal dimension, lacunarity, and ht-index (head/tail breaks index) can be used to explain this. Box-counting fractal dimension is used to represent the New York City region as the most prosperous of the four city regions. Lacunarity indicates the New York City region as the most compact area in the United States. Ht-index shows the New York City region having the highest hierarchy of the four city regions. This conforms to central place theory: higher-level cities have better service than lower-level cities. In addition, ht-index cannot represent hierarchy clearly when data distribution does not fit a long-tail distribution exactly. However, the ht-index is the only method that can analyze the complexity of natural cities without using images.
10
McBride, Melissa. "The study of responses mediated by α₂ and αâ‚-adrenoceptors in the tail and mesenteric resistance arteries from transgenic mice." Thesis, University of Glasgow, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400694.
Full text
11
Neilson, Hilding, Richard Ignace, Beverly Smith, Gary Henson, and Alyssa Adams. "Evidence of a Mira-like tail and bow shock about the semi-regular variable V CVn from four decades of polarization measurements." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/6233.
Full textAbstract:
Polarization is a powerful tool for understanding stellar atmospheres and circumstellar environments. Mira and semi-regular variable stars have been observed for decades and some are known to be polarimetrically variable, however, the semi-regular variable V Canes Venatici displays an unusually large, unexplained amount of polarization. We present ten years of optical polarization observations obtained with the HPOL instrument, supplemented by published observations spanning a total interval of about forty years for V CVn. We find that V CVn shows large polarization variations ranging from 1 - 6%. We also find that for the past forty years the position angle measured for V CVn has been virtually constant suggesting a long-term, stable, asymmetric structure about the star. We suggest that this asymmetry is caused by the presence of a stellar wind bow shock and tail, consistent with the star's large space velocity.
12
LIU, QINGLING. "A Case Study on the Extraction of the Natural Cities from Nightlight Image of the United States of America." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-16243.
Full textAbstract:
The boundaries of the cities are not immutable, they can be changed. With the development of the economies and societies, the population and pollution of cities are increasing. Some urban areas are expanding with more population or other dynamics of urbanization, while other urban areas are reducing with the changing of the dynamics. Therefore, detecting urban areas or delineating the boundaries of the cities is one of the most important steps for urban studies, which is closely related to human settlements and human activities. Remote sensing data (RS) is widely used to monitor and detect land use and land cover on the surface of the earth. But the extraction of urban areas from the ordinary RS data is not easy work. The Operational Linescan System (OLS) is the sensors of the Defense Meteorological Satellite Program (DMSP). The nighttime lights from the DMSP/OLS provide worldwide remotely sensed data to analyze long-term light emissions which are closely related to human activities. But the nighttime lights imagery data contains inherent errors. Therefore, the approaches to calibrate the data and extract the urban areas from the data are complicated. The long-term objective of this thesis is to delineate the boundaries of the natural cities of the continental United States of America (USA) from 1992 to 2010 of nightlight imagery data with all the different satellites. In this thesis, the coefficients for the intercalibration of the nightlight imagery data have been calculated based on the method developed by Elvidge, et al. (2009), but the coefficients are new and available. The approach used to determine the most appropriate threshold value is very important to eliminate the possible data error. The method to offset this possible error and delineate the boundaries of the cities from nightlight imagery data is the head/tail breaks classification, which is proposed by Jiang (2012b). The head/tail breaks classification is also useful for finding the ht-index of the extracted natural cities which is developed by Jiang and Yin (2013). The ht-index is an indicator of the underlying hierarchy of the data. The results of this study can be divided into two categories. In the first, the achieved coefficients for the intercalibration of nightlight images of the continental USA are shown in a table, and the achieved data of the urban areas are stored in a data archive. In the second, the different threshold values of the uncalibrated images and the individual threshold value of the calibrated images are shown in tables, and the results of the head/tail breaks classification and power law test are also drawn. The results show that the acquired natural cities obey the power law distribution. And the results also confirm that the head/tail breaks classification is available for finding a suitable threshold value for the nightlight imagery data. Key words: cities’ boundaries; DMSP/OLS; head/tail breaks classification; nighttime lights; power law; urban areas
13
Hörmann, Wolfgang, and Gerhard Derflinger. "Rejection-Inversion to Generate Variates from Monotone Discrete Distributions." Department of Statistics and Mathematics, Abt. f. Angewandte Statistik u. Datenverarbeitung, WU Vienna University of Economics and Business, 1996. http://epub.wu.ac.at/1176/1/document.pdf.
Full textAbstract:
For discrete distributions a variant of rejection from a continuous hat function is presented. The main advantage of the new method, called rejection-inversion, is that no extra uniform random number to decide between acceptance and rejection is required which means that the expected number of uniform variates required is halved. Using rejection-inversion and a squeeze, a simple universal method for a large class of monotone discrete distributions is developed. It can be used to generate variates from the tails of most standard discrete distributions. Rejection-inversion applied to the Zipf (or zeta) distribution results in algorithms that are short and simple and at least twice as fast as the fastest methods suggested in the literature. (author's abstract)Series: Preprint Series / Department of Applied Statistics and Data Processing
14
Pogson, Aimee L. "Tree Frog Madness." Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1245380440.
Full text
15
Bracewell, Rob. "FROG and PS FROG : a study of two reactionless ocean wave energy converters." Thesis, Lancaster University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301820.
Full text
16
McIntyre, Jayne. "Tail biting in pigs." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275520.
Full text
17
Kvarnström, Joakim. "Searching for Titan's tail." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-356306.
Full textAbstract:
We have used Cassini measurements of electron density from Saturn's magnetosphere to search for a plasma tail behind the moon Titan. Such a plasma tail would consist of plasma that manage to escape Titan's gravitational pull and leave Titan's ionosphere to contribute to the plasma distribution in the Saturn system. The Cassini spacecraft was in orbit around Saturn for 13 years and performed 127 close flybys of Titan as well as many passes through Titan's orbit within the planets plasma-filled magnetosphere. We have used measurements of electron density from the Langmuir probe instrument, built by the Swedish Institute of Space Physics in Uppsala to search for such a tail. The data was analyzed in terms of looking at the spatial distribution of plasma around Titan and Saturn by examining the plasma density in Titan’s orbit in comparison to the rest of system, as well as comparisons of plasma density in front of Titan and behind Titan. The analysis provided no evidence of an extended plasma tail or torus.
18
Gentz, Maria [Verfasser]. "Pig tail biting in different farrowing and rearing systems with a focus on tail lesions, tail losses and activity monitoring / Maria Gentz." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1214440193/34.
Full text
19
Dzindzalieta, Dainius. "Tight Bernoulli tail probability bounds." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140512_103743-38560.
Full textAbstract:
The purpose of the dissertation is to prove universal tight bounds for deviation from the mean probability inequalities for functions of random variables. Universal bounds shows that they are uniform with respect to some class of distributions and quantity of variables and other parameters. The bounds are called tight, if we can construct a sequence of random variables, such that the upper bounds are achieved. Such inequalities are useful for example in insurance mathematics, for constructing effective algorithms. We extend the results for Lipschitz functions on general probability metric spaces.Disertacijos darbo tikslas – įrodyti universalias tiksliąsias nelygybes atsitiktinių dydžių funkcijų nukrypimo nuo vidurkio tikimybėms. Universalios nelygybės pažymi, kad jos yra tolygios pagal tam tikras bendras skirstinių klases ir pagal atsitiktinių dydžių kiekį, kartais ir pagal kitus parametrus. Nelygybės vadinamos tiksliosiomis, jeigu pavyksta sukonstruoti atsitiktinių dydžių seką, kuriai nelygybės virsta lygybėmis. Tokios nelygybės labai naudingos, pavyzdžiui, draudimo matematikoje, konstruojant efektyvius algoritmus. Disertaciją sudaro šeši skyriai. Pirmasis skyrius yra įvadas, kuriame neformaliai pristatomas disertacijoje tiriamas objektas, pateikiamas bendras darbo aprašymas ir motyvacija. Detalesnė kitų autorių rezultatų apžvalga pateikiama atskirai kiekviename skyriuje. Antrasis skyrius skirtas atvejui, kai atsitiktiniai dydžiai yra aprėžti ir simetriniai. Trečiajame skyriuje įrodomos nelygybės atsitiktiniams dydžiams, tenkinantiems dispersijos aprėžtumo sąlygą. Ketvirtajame skyriuje nagrinėjamos sąlyginai aprėžtų atsitiktinių dydžių sumos. Penktajame skyriuje tiriamos atsitiktinių dydžių sekos, sudarančios martingalą arba supermartingalą, ir joms gaunamos universaliosios tikimybinės nelygybės ir sukonstruojama nehomogeninė Markovo grandinė, kuri yra martingalas, ir kuriai minėtos nelygybės virsta lygybėmis. Šeštajame skyriuje rezultatai yra apibendrinami atsitiktinių dydžių sekos Lipšico funkcijoms.
20
Rutherford, Mark Allen. "Synaptic exocytosis in the frog sacculus /." view abstract or download file of text, 2005. http://wwwlib.umi.com/cr/uoregon/fullcit?p3190546.
Full textAbstract:
Thesis (Ph. D.)--University of Oregon, 2005.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 76 - 80). Also available for download via the World Wide Web; free to University of Oregon users.
21
Spink, Benjamin. "The tale of the tail : the role of myosin VI tail domains in processive stepping /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Full text
22
Amish, Stephen Joseph. "Ecosystem engineering beaver and the population of Columbia spotted frogs in western Montana /." Connect to this title online, 2006. http://etd.lib.umt.edu/theses/available/etd-01172007-105600/.
Full text
23
Gavin, Trisha. "A process and outcome evaluation of community Tai Chi programs for older adults." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ65240.pdf.
Full text
24
Flingdal, Mana Trio. "The Broken Tail On a Lizard." Thesis, Konstfack, Inredningsarkitektur & Möbeldesign, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-5304.
Full textAbstract:
In this project I have investigated how a set of rules can be applied to a particular sight and program. Inspired by the rules of the ’divine ‘proportion I applied its system of repetition and algorithm in a particular site and created a bridge with a diverse program beyond the simple intention of bridging two ends. This project is a way of approaching the complexity of designing an architectural space. It is a helping guide on how, through a system I could evaluate and pay attention to spatial qualities. My system is based on the divine proportion and its parts. I have broken up the divine rectangle and used the parts to create a structure that connects the tow ends on this specific sight. In this project I have been investigating and testing how a sett of rules can be applied on a sight to crate proportion, composition and rhythm. The classic rule that is about movement in space, giving function to the space, the relation to the human body and a space being more diverse. These rules are the basics of the foundation of or field. The metaphor I have used is the broken tail of a lizard, that from the point of where it brakes takes another shape and creates a new structure, overlapping and connecting the old and the new. I have called this ”the nature’s broken proportions”. By that I mean, when the symmetry in the creation in the new tail is broken or reduced, it no longer is a continuation of the lizard’s body in that time and space, but an individually separated continuity with its own symmetry. It exist in parallel and as an extension of its past. The system I have created have helped me to define the boundaries and provided a clear structure of my design. This project is to me about connecting my intuition on how life is withe how I design space. The structure and boundaries provided by this system of ”broken proportions”, has given me the tools to evaluate the quality of the spaces I created. I found freedom in my abstraction of this system by breaking up the logarithmic spiral, which is about continuity. This is a designing tool I used to create my bridge. My work is an illustration of a subjective idea, of breaking the continuity in space and time. Through using this system I could evaluate qualities like dimension, proportion, composition, rhythm, direction, sectioning and levels. All these quality’s given by this system, creates an abstract interpretation about my personal view of movement of this bridge.
25
Briggs, Randall (Randall Miller). "Tail use in bioinspired quadrupedal locomotion." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74491.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 17-18).
Tails are seen in nature to be used in an amazing number of different applications. Many of these applications seen in nature may be of use to bioinspired roboticists in the future. I have provided a brief review of tail use as seen in nature. An experiment was performed using the MIT Cheetah to investigate the usefulness of tails in one particular instance. The Cheetah was set to stand while a large, standardized disturbance was introduced by means of a clay "wrecking ball." Two cases were observed: one where the tail was actively stationary and another where the tail was swung in order to counteract the disturbance. The actively swung tail was seen to keep the body in the stable region longer than the stationary tail, thus providing the robot additional time to correct for the disturbance with the next foot fall.
by Randall Briggs.
S.B.
26
Pan, Yue. "Topological Origin of the Urbach Tail." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1235514573.
Full text
27
Clay, Talia. "Book of Christabelle: A Devil's Tail." NSUWorks, 2013. http://nsuworks.nova.edu/writing_etd/13.
Full text
28
Krupskii, Pavel. "Structured factor copulas and tail inference." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/48390.
Full textAbstract:
In this dissertation we propose factor copula models where dependence is modeled via one or several common factors. These are general conditional independence models for $d$ observed variables, in terms of $p$ latent variables and the classical multivariate normal model with a correlation matrix having a factor structure is a special case. We also propose and investigate dependence properties of the extended models that we call structured factor copula models. The extended models are suitable for modeling large data sets when variables can be split into non-overlapping groups such that there is homogeneous dependence within each group. The models allow for different types of dependence structure including tail dependence and asymmetry. With appropriate numerical methods, efficient estimation of dependence parameters is possible for data sets with over 100 variables.
The choice of copula is essential in the models to get correct inferences in the tails. We propose lower and upper tail-weighted bivariate measures of dependence as additional scalar measures to distinguish bivariate copulas with roughly the same overall monotone dependence. These measures allow the efficient estimation of strength of dependence in the joint tails and can be used as a guide for selection of bivariate linking copulas in factor copula models as well as for assessing the adequacy of fit of multivariate copula models.
We apply the structured factor copula models to analyze financial data sets, and compare with other copula models for tail inference. Using model-based interval estimates, we find that some commonly used risk measures may not be well discriminated by copula models, but tail-weighted dependence measures can discriminate copula models with different dependence and tail properties.Science, Faculty of
Statistics, Department of
Graduate
29
Hutchinson, Robert B. "Control of the Coqui frog, Eleutherodactylus coqui." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7034.
Full textAbstract:
Eleutherodactylus coqui is an invasive species whose unchecked population growth is having environmental and social impacts on the Hawaiian islands. One focus was to fine tune doses of possible toxicants to control the frogs. It was found that applied as a spray, a 1% caffeine and 0.01% pyrethrin cocktail yielded complete mortality in a single application. These concentrations could be tested in field trials. Animals treated with the caffeine/pyrethrin cocktail experienced decreases in liver and muscle glycogen and severe hyperglycemia. This is consistent with known phosphodiesterase inhibition triggering enzyme inhibitions that ultimately lead to lethality. IBMX, a caffeine analogue and potent phosphodiesterase inhibitor, when combined with pyrethrin, had a similar effect. Drugs blocking other possible modes of action such as adenosine antagonism and ryanodine receptor opening had no effect. It was therefore suggested that caffeine in combination with pyrethrin might be an effective method for controlling frog populations and the lethality of the treatment may be due to phosphodiesterase inhibition followed by eventual hyperkalemia.vii, 32 leaves
30
Maullu, Bärbel. "Untersuchung ultrakurzer Laserimpulse mit der FROG-Methode." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=981207723.
Full text
31
Wu, Yuxin. "Bioactive peptides from Rana (Odorrana) frog secretions." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603569.
Full textAbstract:
The studies described in this thesis have focused on the bioactive peptides secreted from the skin glands of Rana (Odorrana) frogs, using different techniques to identify the sequences of novel peptides and to subsequently clone their precursors by molecular genetic techniques and finally, to chemically-synthesize these peptides and examine their bioactivities. Chapters I and 2, respectively, give a general introduction to the field of research and describe the scientific techniques employed in the work. The first experimental chapter, Chapter 3, describes two novel non-canonical bradykinin antagonist peptides isolated from the skin secretion of Odorrana versabilis which contain a "Rana box"-like structure at their C-terminals- a motif that is normally present in antimicrobial peptides. Chapter 4 describes a novel tachykinin peptide which was isolated from the skin of Rana chensinensis, and is strongly suspected of being an NKI receptor agonist. Chapter 5 describes the identification of two novel peptides from the skin secretions of Odorrana versabifis and Odorrana livida, which possess a moderate degree of specific antifungal activity. How their similar primary structures with only two residue substitutions, can cause an apparent 4-fold difference in potency is an interesting observation worthy of further indepth study. Chapter 6 describes a study that focuses on a Bowman-Birk trypsin inhibitor peptide from Odorrana schmackeri skin secretion and its position 9 substituted analogue. The most interesting result was the discovery of their multi-functional effects, not only against the proteases, trypsin and chymotrypsin, but also extending to growth inhibitory effects on cancer cell lines, tryptase inhibition and even to smooth muscle effects. The structure/function relationships of these peptides require further in-depth investigations. Chapter 7 describes a novel vasodilator peptide, named vasorelaxin, isolated from Odorrana schmackeri skin secretion with a potency approaching two orders of magnitude greater than canonical bradykinin. These data further illustrate that Rana (Odorrana) frogs skin secretions remain an important resource for novel peptide discovery, some of which may possess therapeutic properties.
32
Jones, Clifford David. "Asymmetric synthesis of the frog alkaloid epibatidine." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262966.
Full text
33
Hudson, Michael. "Conservation management of the mountain chicken frog." Thesis, University of Kent, 2016. https://kar.kent.ac.uk/57950/.
Full textAbstract:
Global biodiversity is being lost at an unprecedented rate, such that we have entered the sixth mass extinction in the history of the earth with emerging infectious diseases (EID) recognised as an important contributor to this loss. Amphibian chytridiomycosis is an EID that has driven very rapid declines in, or even extinctions of, hundreds of amphibian species. Infectious diseases such as chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), often persist in biological and non-biological reservoirs making them difficult to eradicate. In turn, this makes reintroductions of target species challenging due to the risk of infection. This thesis investigates the critically endangered mountain chicken (Leptodactylus fallax) as a case study of the population impacts of a chytridiomycosis epidemic and to test the effectiveness of strategies to mitigate the effects of the disease. Specifically, this research (1) charts the decline of the mountain chicken on the only two islands on which it exists, and determines the impact on genetic diversity; (2) tests whether anti-fungal treatment can improve the survival of mountain chickens with Bd infection in the wild; (3) examines the role of Bd reservoir species in causing Bd infections of reintroduced mountain chickens; and (4) determines habitat features that are predictors of infection at release sites. Chytridiomycosis drove the mountain chicken to near extinction on Dominica in 2002 and Montserrat in 2009, in one of the fastest recorded vertebrate species declines, leading to a significant loss of genetic diversity. On Montserrat, treating mountain chickens with an anti-fungal drug (itraconazole) during the chytridiomycosis epidemic improved survival rates and reduced Bd infection rates in the short term, but did not provide long-term protection. Although mountain chickens have been driven to near-extinction by Bd infection on Montserrat, the pathogen persists in two sympatric reservoir species which are not impacted by Bd infection, the most prolific of which (Eleutherodactylus johnstonei) displays strong seasonality in Bd infection prevalence and load. Timing mountain chicken reintroduction to occur during the period when tree frog Bd infection was at its lowest was tested to determine the impact on reintroduction success. Multi-state mark-recapture modelling applied post-release showed that optimising the timing of release reduced Bd infection rates and increased survival. Radio-tracking was utilised with geographic profiling to determine that release site water bodies were likely sources of Bd infection in reintroduced mountain chickens. This could inform targeted mitigation of the pathogen and improve future reintroduction success. Where species have been extirpated in the wild, and an irreversible threat such as an EID persists, novel reintroduction strategies are required. These include optimising the timing and conditions of release in order to minimise the impact of the threat along with targeted mitigation measures such as individual level treatments.
34
Sutton, William Bradley. "The ecology and natural history of the Northern Leopard Frog, Rana pipiens Schreber in West Virginia." Huntington, WV : [Marshall University Libraries], 2004. http://www.marshall.edu/etd/descript.asp?ref=458.
Full textAbstract:
Thesis (M.S.)--Marshall University, 2004.Title from document title page. Includes abstract. Document formatted into pages; contains viii, 110 including illustrations. Includes bibliographical references (p. 98-103).
35
Bayon, De Noyer Maxime P. "Tail buffet alleviation of high performance twin tail aircraft using offset piezoceramic stack actuators and acceleration feedback control." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/12499.
Full text
36
Thurgate, Nicole. "The Ecology of the Endangered Dusky Gopher Frog (Rana Sevosa) and a Common Congener, the Southern Leopard Frog (Rana Sphenocephala)." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/433.
Full textAbstract:
Many amphibian populations are rapidly disappearing throughout the world. An important issue for ecologists is why some amphibian species are more susceptible to decline than others. Here I present five experiments that compare the performance of an endangered (Rana sevosa) and a common (Rana sphenocephala) frog in changing habitats, to determine why these two species differ in their persistence. I include additional studies investigating the habitat requirements and behavior of R. sevosa. I found that habitat change in the form of canopy closure over breeding ponds negatively affects both species, making them smaller as tadpoles and at metamorphosis. The magnitude of size differences was greater for R. sevosa and this species was less likely to survive in closed canopy ponds. Larval survival was not affected in R. sphenocephala and this is likely a key reason for the persistence of this species in habitats where R. sevosa has been extirpated. The introduction of fish to breeding ponds would also differentially affect the two species. R. sevosa did not display behavioral defenses to the threat of fish predation while R. sphenocephala did. R. sevosa displayed a preference for certain characteristics in its habitat including open canopy ponds, grassy terrestrial habitats and an abundance of burrows. An association with the chemical cues of burrow making organisms suggests that these organisms may be important for R. sevosa. Therefore, specialized habitat requirements and behaviors which may be contributing to its decline. I found some evidence of asymmetric competition in the larval stage with R. sevosa negatively affecting R. sphenocephala. It does not appear that larval competition with R. sphenocephala has contributed to the decline of R. sevosa. The primary difference between the two species was in responses to habitat change. R. sevosa appears to be rigid in its habitat requirements and behavior and its inability to respond and adapt to change is a key component of its rarity. By contrast R. sphenocephala showed an ability to cope with habitat changes. Conservation of R. sevosa will require suitable management of the aquatic and terrestrial habitats, primarily through the instigation of an appropriate fire regime.
37
Karamolegkos, Konstantinos. "Ducted Tail Rotor Perfomance Prediction Using CFD." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9241.
Full textAbstract:
Aviation industry has a crucial impact on society on the grounds that it offers wider social and economic benefits. The demand of transportation is increasing and it is expected that the worldwide fleet of aircraft and rotorcraft will increase accordingly. This growth will introduce an increased environmental impact which can be controlled with the introduction and the implementation of new and greener technologies which can provide both a reduced carbon foot-print and increased efficiency. Therefore, the simulation of new designs with tools that can capture the flow physics accurately is crucial, on the grounds that an accurate simulation could provide novel designs and new ways in order to design from scratch new vehicles as well as providing a better appreciation of the physics that are involved. This work has a central aim to propose a methodology which combines CFD simulations and the method of performance mapping. It focuses on the application of a ducted tail rotor which can offer significant performance benefits compared to a conventional tail rotor. The developed methodology was tested against the results of an in-house rotorcraft comprehensive code and provided a reasonable qualitative correlation. In principle, this methodology can work for all helicopter flight phases such as hover, climb, cruise, descend but due to the complexity of the investigations, together with the lack of experimental data that can be used to refine the CFD model, only the hover and forward flight were considered. Although CFD studies of a ducted tail rotor currently exist in the literature (though scarce), this work can be considered, to the best knowledge of the author as a first attempt in investigating the performance of the configuration, from low to high forward flight speed, by combining CFD and performance mapping.
38
Funnell, M. E. (Marc Edwin). "Helicopter tail boom vibration analysis and suppression." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52873.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: An experimental investigation was conducted usmg a cantilever beam to illustrate an understanding of vibration techniques and phenomena. The [Tee and forced vibration of the cantilever beam was investigated using various modelling strategies. Theoretical models such as the Lumped parameter, Myklestad, Distributed Parameter and Finite Element Methods were analysed and compared with experimental measurements. Excellent agreement of the natural frequencies, mode shapes and the harmonic transfer functions were found. To investigate tail boom vibration, a Finite Element Model of a simplified helicopter tail boom design was tested against experimentally measured data. The results correlated accurately and the model was used to evaluate the effectiveness of a vibration suppression system designed for the tail boom. The vibration suppression system was designed using two, parallel dynamic absorbers to reduce tail boom vibrations at its two dominant frequencies. For the purposes of this thesis, the dynamic absorbers were tuned to reduce the resonant peaks at the dominant excitation frequencies of the excitation force in-line with the thrust of the tail rotor only. This excitation force was estimated using a simplified tail rotor dynamic model, which when compared with actual vibration data was assumed to predict the basic frequency trends of the force, reliably. Incorporating the designed components into an accurate Lumped Parameter model of a cantilever beam structure and simulating the response of the structure at the dominant excitation frequencies of the calculated excitation force, tested the vibration suppression system. The results of this investigation proved the effectiveness of the design procedure and optimisation process of the design parameters. A similarly designed suppression system was incorporated into the Finite Element tail boom model and from the analytical results obtained it was shown to cause a fair reduction in the vibration response at the two dominant frequencies of the excitation force. Finally, two possible applications were suggested from the research presented in this thesis. The first application was the simplified configuration of a vibration monitoring system for the tail boom. The second application was the possible development of a system using the response of vibration suppression absorbers to predict the magnitudes of the excitation forces on the tail boom.
AFRIKAANSE OPSOMMING: 'n Experimentele ondersoek is ondemeem deur gebruik te maak van 'n ingeklemde balk om vibrasie tegnieke te illustreer. Die vrye en geforseerde vibrasie van die ingeklemde balk is ondersoek deur verskillende model tegnieke te gebruik. Teoretiese modelle soos die Lumped parameter, Myklestad, Distributed Parameter en Eindige Element Metodes was geanaliseer en vergelyk met die eksperimentele waardes. Uitstekende ooreenstemmings was gevind tussen die natuurlike frekwensies, die eievektore en die harmoniese oordragsfunk:sie. Om stert vibrasie te ondersoek, was'n eindige element model van 'n helikopter stert getoets teenoor die eksperimentele data. Die resultate het akuraat gekorreleer en dus was die model gebruik om die effektiwiteit van 'n vibrasie supressie sisteem te evalueer. Die vibrasie supressie sisteem was ontwerp deur gebruik te maak van twee parallele dinamiese absorbeerders om die helikopter stert se eerste twee dominante vibrasie frekwensies te minimeer. Vir die doel van hierdie tesis was die dinamiese absorbeerders ingestel om net die resonante pieke van die opgewende krag wat in lyn is met die drykrag van die stert rotor te minimeer Hierdie opgewende krag was, deur gebruik te maak van 'n basiese stert rotor dinamiese model, aanvaar om die basiese frekwensie tendense van die krag te voorspel. Die supressie sisteem wat ontwerp was, was getoets op die lumped parameter balk en het veroorsaak dat die voorspelde opgewende krag by al twee van sy dominante . frekwensies baie geminirneer was. Die effektiwiteit van die sisteem was dus bewys en die sisteem was gebruik om die respons van die eindige element model van die stert te verbeter. Die resultate het 'n aanvaarbare reduksie in die respons by die twee dominante frekwensies van die opgewende krag, gewys. Laastens, deur gebruik te maak van die resultate in hierdie tesis. was twee moontlikhede voorgestel. Die eerste een was die konfigurasie van 'n vibrasie moniterings sisteem vir die helikopter stert. Die tweede mmontlikheid was die moontlike ontwikkeling van 'n sisteem wat die grootte van die opgewende krag by die stert rotor kon voorspel, deur gebruik te maak van die vibrasie suppressie absorbeerders.
39
Kauppila, M. (Mikko). "Hedge fund tail risk:performance and hedging mechanisms." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201412042095.
Full textAbstract:
The goal of this master’s thesis is to understand the performance implications of hedge fund’s tail risk, and the mechanisms of how some funds achieve lower tail risk. The current evidence on the performance implications is mixed, with most empirical hedge fund studies suggesting higher returns to higher risk. This is not obvious since the goal of skillful hedge fund managers is to deliver positive risk-adjusted returns, and indeed a few studies do report higher returns to lower risk. The issue is further complicated by the evidence of asset-level low-risk anomalies, which could create a low-skill alternative for managers to achieving higher returns with lower risk.
Using a consolidation of commercial hedge fund databases, we decompose hedge fund tail risk, conditional on market distress, into two components: Systematic Conditional Tail Risk (SCTR) arising predictably via equity market exposure, and Idiosyncratic Conditional Tail Risk (ICTR) arising from unpredictable, proprietary alpha investment technology. First, using a subset of large, 13F-HR matched hedge funds from March 2000 to June 2013, we show that especially low-ICTR hedge funds deliver superior future risk-adjusted returns. In contrast to existing hedge fund literature our results support the broader view in asset-pricing literature that low risk is associated with higher risk-adjusted returns. The results are robust to the inclusion of additional risk factors, including a low-risk factor, suggesting that the better performance could be due to skillful hedging rather than harvesting of low-risk anomalies. This skill hypothesis is further supported by the finding that low-risk funds charge higher incentive fees, consistent with economic theory.
To further resolve the puzzle of whether low-risk funds outperform high-risk funds, using a large set of funds from January 1994 to June 2013, we run a comprehensive “horse race” between our risk measures and a replication of a large array of existing risk measures. Our results show that for many existing risk measures, the purported risk premium largely diminishes when controlling fund size, suggesting that existing results may be somewhat driven by the inclusion of smaller funds. Our measures SCTR and ICTR consistently show low-risk funds outperforming high-risk funds.
Second, using 13F-HR option holdings data from March 1999 to June 2013, we investigate the underlying hedging mechanism implemented by low tail risk hedge funds. We demonstrate that low-SCTR funds allocate a high fraction of their wealth — consistently over time — to protective option strategies, while low-ICTR funds use costly protective strategies only during the financial crisis. Funds with low ICTR also employ more stock, but not index, options, which fits the idiosyncratic nature of the measure.
After the financial crisis, volatility-linked Exchange Traded Products (ETPs) have emerged as a potential alternative to hedging tail risk. We show that, from April 2009 to June 2013, the use of such volatility-linked ETPs is associated with lower SCTR but not ICTR, consistent with the option result, and indeed suggesting a complementary hedging mechanism.
40
Snowball, Jeanette D. "Festival fringe production and the long tail." Economic Research Southern Africa (ERSA), 2016. http://www.econrsa.org/node/1170.
Full textAbstract:
Publisher versionIn the past 15 years, there has been a worldwide proliferation of arts festivals, including so-called "fringe" festivals, which encouraged more experimental and avant-garde productions. While fringe festival productions had the potential to generate significant income for producers, their aims were primarily related to artistic innovation and it is well known that putting on a fringe show is highly unlikely to provide financial gain for most producers. This is what is referred to in statistics and marketing as a "long tail" distribution, in which a minority of producers in a particular market earn the vast majority of industry income. However, for individual producers of live theatre, such a distribution represents high risks and potentially large financial losses. This article uses producer data from two different fringe festivals in South Africa to explore determinants of ticket sales and box-office income. Included in the analysis is a consideration of the impact of genre and pricing strategies on the probability (Logit model) of shows being in the top 10%, 30% and 50% of best-selling and earning productions. Results support the long tail hypothesis.
41
Santos, Eduardo Alonso Marza dos. "Tail risk in the hedge fund industry." reponame:Repositório Institucional do FGV, 2015. http://hdl.handle.net/10438/13797.
Full textAbstract:
Submitted by Eduardo Alonso Marza dos Santos (eduardo.marza.santos@gmail.com) on 2015-06-21T10:30:55Z
No. of bitstreams: 1
Eduardo_A_M_Santos.pdf: 646820 bytes, checksum: aaba122a576d7c75ad0e5803539c25d4 (MD5)Approved for entry into archive by Suzinei Teles Garcia Garcia (suzinei.garcia@fgv.br) on 2015-06-22T11:46:18Z (GMT) No. of bitstreams: 1 Eduardo_A_M_Santos.pdf: 646820 bytes, checksum: aaba122a576d7c75ad0e5803539c25d4 (MD5)
Made available in DSpace on 2015-06-22T11:56:18Z (GMT). No. of bitstreams: 1 Eduardo_A_M_Santos.pdf: 646820 bytes, checksum: aaba122a576d7c75ad0e5803539c25d4 (MD5) Previous issue date: 2015-05-28
The dissertation goal is to quantify the tail risk premium embedded into hedge funds' returns. Tail risk is the probability of extreme large losses. Although it is a rare event, asset pricing theory suggests that investors demand compensation for holding assets sensitive to extreme market downturns. By de nition, such events have a small likelihood to be represented in the sample, what poses a challenge to estimate the e ects of tail risk by means of traditional approaches such as VaR. The results show that it is not su cient to account for the tail risk stemming from equities markets. Active portfolio management employed by hedge funds demand a speci c measure to estimate and control tail risk. Our proposed factor lls that void inasmuch it presents explanatory power both over the time series as well as the cross-section of funds' returns.
O objetivo do trabalho é quanti car o prêmio de risco de cauda presente nos retornos de fundos de investimento americanos. Risco de cauda é o risco de perdas excepcionalmente elevadas. Apesar de ser um evento raro, a teoria de apreçamento de ativos sugere que os investidores exigem um prêmio de risco para reter ativos expostos a eventos negativos extremos (eventos de cauda). Por de nição, observações extremas têm baixa probabilidade de estarem presentes na amostra, o que di culta a estimação dos impactos de risco de cauda sobre os retornos e reduz o poder de técnicas tradicionais como VaR. Os resultados indicam que não é su ciente controlar somente para o risco de cauda do mercado de capitais. A gestão ativa de portfólio por parte dos gestores de fundos requer uma medida própria para estimação e o controle de risco de cauda. O fator de risco de cauda que propomos cumpre este papel ao apresentar poder explicativo tanto na série temporal dos retornos quanto no corte transversal.
42
Yu, Tony S. (Tony Sheung). "Elastic tail propulsion at low Reynolds number." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38700.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 73-76).
A simple way to generate propulsion at low Reynolds number is to periodically oscillate a passive flexible filament. Here we present a macroscopic experimental investigation of such a propulsive mechanism. A robotic swimmer is constructed and both tail shape and propulsive force are measured. Filament characteristics and the actuation are varied and resulting data are quantitatively compared with existing linear and nonlinear theories.
by Tony S. Yu.
S.M.
43
Karabay, Arzu. "Ncd Motor Tail Domain Interactions With Microtubules." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/11280.
Full textAbstract:
Drosophila nonclaret disjunctional (Ncd) is a kinesin-like C-terminal motor protein that is involved in spindle assembly in oocytes during meiosis and in spindle maintenance in early embryos during mitosis. Ncd interacts with both "highway" and "cargo" microtubules (MTs) in meiotic and mitotic spindles through the action of ATP-dependent and ATP-independent MT binding sites in the head and tail domains, respectively. Through the action of these binding sites, Ncd bundles and, perhaps, slides MTs relative to each other. These functions are important for the in vivo role of Ncd in the formation of the bipolar spindle and maintenance of the spindle assembly.
Despite the high homology of the Ncd head domain to the kinesin head domain, the Ncd tail domain is unique among kinesin-like motor proteins. Characterization of ATP-independent interactions of Ncd with cargo MTs and identification of MT binding sites (located in amino acid residues 83-100 and 115-187) in the tail region by MT co-sedimentation assays revealed that the Ncd tail has functional similarities to microtubule-associated proteins, especially to tau and MAP2, that regulate MT assembly. Like tau MT binding motifs, MT binding sites of the tail domain are rich in basic amino acids that are flanked by proline residues. Cross-linking and MT co-sedimentation assays with subtilisin-digested MTs demonstrated that Ncd tail binding sites (located at the extreme C-terminus and in the H11-H12 loop / H12 helix of each tubulin monomer) on tubulin correspond to tau binding sites. Further, the Ncd tail domain, like tau, can promote and stabilize MT assembly under conditions that induce MT disassembly.
Taken together, these results suggest that the Ncd tail functions both in the transport of cargo MTs to spindle poles for the formation of the spindle assembly during meiosis, and in maintenance of spindle assembly during mitosis. How these different functions of Ncd are regulated still remains unknown, however further understanding of the regulation of Ncd function should contribute to our knowledge of cell cycle regulation in both meiotic and mitotic cells.Ph. D.
44
Igram, Dale J. "A Topological Explanation of the Urbach Tail." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1459885929.
Full text
45
Diamant, Aristides G. "The structure of the cytoplasmic dynein tail." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/249014.
Full textAbstract:
Cytoplasmic dynein is a molecular motor that moves cargos along microtubules. Dynein, together with its large co-factor dynactin, is responsible for the vast majority of traffic towards the centre of the cell. The largest subunit of the dynein complex is called the dynein heavy chain (DHC). The DHC includes a C-terminal motor domain, which converts ATP hydrolysis into mechanical force, an N-terminal tail domain, and a flexible linker domain to join the two together. An intermediate chain (DIC) and light intermediate chain (DLIC) bind directly to the DHC tail, while light chains (DLCs) bind to the DIC. This tail complex is important for both cargo binding as well as homodimerisation of the DHC, which is necessary for processive movement. Previous studies suggest that the DLCs play an important role in homodimerisation, but it remains unclear how else the DHCs are held together. Using S. cerevisiae as a model system, I co-expressed all four dynein subunits and purified functional dynein motors. In this background, I found that truncating the DHC to include only the first 1004 residues (out of the total 4092) eliminates the motor domain as well as the flexible linker domain, while preserving binding to the DIC, DLIC and DLC. However, truncating just another 50 residues off of the C-terminus led to a loss of all accessory subunits. I developed a protocol for expressing and purifying large quantities of the 1004 residue construct, thus I provide the first description of a recombinant dynein tail domain. Using negative stain electron microscopy (EM), I also present the first 3D structural information for the tail region of the cytoplasmic dynein motor. I then describe a construct including only the first 557 residues of the DHC, which dimerises despite not being able to bind any of the other subunits. I present a crystal structure of this smaller DHC fragment, which shows that the N-terminal 180 residues of the DHC constitute an intricate dimerisation domain made up of a β-sheet sandwiched between α-helices. Not only is this the first crystal structure of any part of the DHC N-terminus, but it reveals a previously undocumented dimerisation domain within the DHC itself. Furthermore, information garnered from this crystal structure allowed for interpretation of a recent cryo-EM structure of a triple complex containing the dynein tail, dynactin and the cargo adaptor BICD2 (TDB) that was solved by my colleagues in the Carter group. Only by docking the DHC N-terminus crystal structure within the TDB EM density did it become clear that the N-terminus of the DHC is responsible for the majority of the contacts the dynein tail makes with both dynactin and BICD2. Therefore the work that I present here sheds new light on the unexpected importance of the DHC N-terminus and allows two important conclusions to be made. First, the N-terminal 180 residues of the DHC constitute a dimerisation domain of its own. Second, the next ~400 residues of the DHC form a domain that plays a key role in the complex interface between dynein, dynactin and BICD2.
46
Abousaada, Anis Ahmed. "Echo tail canceller based on AIFIR filtering." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5572.
Full textAbstract:
This thesis contributes a computationally efficient echo tail canceller. The proposed structure is an adaptive version of the Interpolated FIR (IFIR) filter. The results obtained with this new approach are compared to those obtained with an AFIR direct form echo canceller. The proposed system requires approximately 31% of the hardware of the AFIR echo canceller. A two-stage echo canceller utilized in the U-interface at Basic Rate Access-ISDN is investigated. The first stage (Main Echo Canceller) is comprised of an AFIR filter which cancels the main echo pulse amid the first few symbol intervals. Cancellation of the echo tail is performed by the AIFIR tail canceller. To evaluate the performance of this architecture, echo impulse responses were produced for the Bellcore loop structures. These investigations were on the effects of parameters such as the passband edge and the stopband attenuation of the interpolator as well as length of the first stage echo canceller. (Abstract shortened by UMI.)
47
Trost, Johanna. "Tail Dependence Considerations for Cross-Asset Portfolios." Thesis, KTH, Matematisk statistik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185201.
Full textAbstract:
Extreme events, heaviness of log return distribution tails and bivariate asymptotic dependence are important aspects of cross-asset tail risk hedging and diversification. These are in this thesis investigated with the help of threshold copulas, scalar tail dependence measures and bivariate Value-at-Risk. The theory is applied to a global equity portfolio extended with various other asset classes as proxied by different market indices. The asset class indices are shown to possess so-called stylised facts of financial asset returns such as heavy-tailedness, clustered volatility and aggregational Gaussianity. The results on tail dependence structure show on lack of strong joint tail dependence, but suitable bivariate dependence models can nonetheless be found and fitted to the data. These dependence structures are then used when concluding about tail hedging opportunities as defined by highly tail correlated long vs short positions as well as diversification benefits of lower estimated Value-at-Risk for cross-asset portfolios than univariate portfolios.Extrema riskhändelser, avkastningsfördelningar med hög kurtosis och bivariat asymptotiskt beroende är viktiga aspekter vid mitigering och diversifiering av extremutfallsrisk inom finans. Dessa områden är i denna masteruppsats undersökta med hjälp av gränsvärdescopulas och beroende- samt riskmått för extremutfall. Teorin är applicerad på en global aktieportfölj till vilken karaktäristiska marknadsindex för regionala aktiemarknader och andra tillgångsslag lagts till. Det visas att dessa index innehar så kallade stiliserade finansiella egenskaper såsom feta svansar, högre volatilitet förekommande i kluster och en mer normalfördelad avkastningsprofil vid lägre frekventa datapunkter. Resultaten om beroendet för bivariata data vid extremutfall visar på en avsaknad av stark gemensam korrelation, men lämpliga sambandsstrukturer lyckas ändå anpassas till datan. Dessa sambandsstrukturer enligt teorin om extremvärdescopulas används för att dra slutsatser om möjligheter att mitigera och diversifiera extremutfallsrisk för bivariata investeringsportföljer genom att antingen gå lång respektive kort positivt svanskorrelerade instrument, eller genom kvantifiering av diversifieringsnytta vid extremutfall.
48
Paloski, Rori A. "Relationship between lakeshore development and anuran populations in Portage County, Wisconsin /." Link to full-text, 2006. http://epapers.uwsp.edu/thesis/2006/paloski.pdf.
Full text
49
Pfanzelt, Sandra. "Differential Dynamic Signal Processing in Frog Vestibular Neurons." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-105490.
Full text
50
Zeyl, Clifford. "Genome evolution in the primitive frog Leipelma hochstetteri." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59969.
Full textAbstract:
The primitive New Zealand frog Leiopelma hochstetteri shows exceptional karyotypic variation. On the North Island, females carry univalent W chromosome and both sexes have 0 to 15 supernumerary chromosomes. Frogs from Great Barrier Island have a conventional 2n = 22 karyotype, with no sex chromosome differentiation in C-banded mitotic chromosomes. However, the lampbrush chromosomes of a Great Barrier Island female show evidence of heterogamety. This suggests that presumed ancestral female heterogamety has persisted on Great Barrier Island and given rise to a WZZ-female/ZZ-male sex chromosome system on the North Island.A repeated sequence, Lh1, varies greatly within populations in copy number and distribution on genomic EcoRI fragments. In situ hybridization revealed the variable presence of large Lh1 arrays on supernumerary chromosomes and two autosomes. The extensive Lh1 variability implies that, like the supernumeraries, it is more selfish than functional in the L. hochstetteri genome.