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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Cdc55 controls the balance of phosphatases to coordinate spindle assembly and chromosome disjunction during budding yeast meiosis

Bizzari, Farid Fouad Mahmoud January 2012 (has links)
Meiosis is the process by which haploid gametes are produced from a diploid cell. It is a specialised form of cell division which involves one round of DNA replication followed by two rounds of chromosome segregation. Errors in the segregation process can give rise to aneuploidy, which can result in miscarriages and birth defects. In the first meiotic division homologous chromosomes are segregated, and sister chromatids are segregated in the second division. This is coordinated with two rounds of spindle microtubule assembly and disassembly. How these two processes are coordinated is unknown. In my PhD, I study the role of the protein phosphatase 2A (PP2A) regulatory subunit, Cdc55, in budding yeast meiosis. PP2A is a conserved heterotrimeric enzyme that has important roles in mitosis and meiosis. These roles are dictated by binding to either of its two regulatory subunits, Rts1 and Cdc55, in budding yeast . I show that Cdc55 is required for the proper assembly of a meiotic spindle in meiosis I, through the maintenance of the Cdc14 phosphatase in the nucleolus early in meiosis. In addition, Cdc55 is also required to limit the formation of PP2A complexes with the Rts1 regulatory subunit, and this is essential for the timely dissolution of sister chromatid cohesion. Thus, Cdc55 couples spindle assembly with chromosome segregation through its interactions with Cdc14 and PP2ARts1. Finally, I show some preliminary studies looking at the possible downstream effectors of Cdc14 that are important in this mechanism.
92

Assessment of remote data capture systems for the characterisation of rock fracture networks within slopes

Gwynn, Xander Peter January 2009 (has links)
The use of remote techniques to capture the geometrical characteristics of rock masses has seen increased use and development in recent years. Apart from the obvious improved Health and Safety aspects, remote techniques allow rapid collection of digital data that can be subsequently analysed to provide input parameters for a variety of geomechanical applications. Remote data capture is a new technique used to collect geotechnical data and little independent work has been done concerning the comparative limitations and benefits of photogrammetry and laser scanning. Photogrammetry and laser scanning produce three dimensional digital representations of a studied rock face which can then be mapped for geotechnical data using specialist software. Research conducted at Camborne School of Mines, University of Exeter has focussed on developing robust and flexible methodologies for remote data capture techniques, namely photogrammetry and laser scanning. Geotechnical characterisation for photogrammetry was tested using the CSIRO Sirovision software and laser scanning was used with SplitFX from Split Engineering. A comparative method of assessing the error between orientation measurements was developed based on calculating the pole vector difference between remotely captured and traditionally hand-mapped data. This allowed for testing of the benefits of the remote data capture systems and limitations whilst comparing them with conventional hand-mapping. The thesis also describes the results of detailed comparisons between hand-mapping, photogrammetric and laser scanned data collection for discontinuity orientation, roughness, discontinuity trace lengths and potential end-use applications. During fieldwork in Cornwall, Brighton Cliffs and northern France it was found that remote data capture techniques struggled to collect orientation data from intensely fractured rock masses where features are primarily represented as discontinuity traces. It was found that both photogrammetry and laser scanning produce orientation data comparable to traditionally mapped data, with an average pole vector difference less than 12° from data mapped from the Tremough Campus road cutting to the University of Exeter’s Cornwall Campus. Set analysis on 151 comparable data points yielded a maximum set pole vector difference of 9.8°, where the closest difference was 2.24°. Testing the accuracy of discontinuity trace orientations captured by photogrammetry using the pole vector difference methods indicate that planar derived orientations are more accurate, with an average difference of 16.67° compared to 37.72°. This thesis contains the reviews and analyses of photogrammetry and laser scanning for use in characterising natural and manmade rock slopes. Improved field and post-processing methodologies have been developed to aid the safe, efficient and suitable geotechnical characterisation of rock fracture networks. The continual development and use of remote mapping techniques, whilst supplementing their unique qualities with traditional mapping, have the capability to revolutionise rock mass mapping. Particular development needed is the implementation of ISRM guidelines to standardise photogrammetric and laser scanning fieldwork and post-processing data analysis.
93

Urbanisation et dynamique des transports "informels" et des mobilités dans les villes secondaires sénégalaises : les cas de Touba, Thiès et Saint Louis / Urbanization and dynamics of informal transports and mobilities in secondary cities in Senegal : cases of Touba, Thiès and Saint Louis

Faye, Djib 12 February 2013 (has links)
La croissance explosive de la population sénégalaise a permis d’atteindre 13 millions d’habitants en 2009 contre 2 millions en 1950. La moitié de cette population, constituée largement de jeunes, vivent dans les zones urbaines comme Touba, Thiès et Saint Louis. Cet essor démographique a conduit à l’extension spatiale et la création de nouvelles centralités dans les villes sénégalaises. Il en résulte des paysages urbains et des fonctions très contrastés. Ce décalage fonctionnel et géographique a créé des besoins de mobilités très fortes.Dans les zones urbaines non planifiés et/ou éloignées des centres, les mobilités de proximité se développent par le biais de la marche à pieds et des transports hippomobiles. Alors que les déplacements menant vers les centres pour des motivations de travail, de commerce, d’études ou d’accès aux services divers se font essentiellement via les transports collectifs motorisés.De toute évidence, les relations entre transport et urbanisme sont ambivalentes. Si l’urbanisation précède le réseau de transport dans les quartiers périphériques, ailleurs, ils jouent un rôle majeur dans la structuration des espaces urbains notamment dans les centres historiques et le long des grands axes routiers.Pourtant, les transports informels opèrent en marge des règles pour satisfaire les besoins de mobilité des usagers à faible revenu. Ce qui rend ainsi éminent le rôle des pouvoirs publics dans la régulation des transports. / Senegal’s population grew in excess of 13 million people in 2009 from 2 million in 1950. The urban population growth led to the spatial extension and centralities of the cities. Half of the population, largely young, lives in urban areas like Touba, Thiès and Saint Louis. That gave a very contrasting urban landscapes and diverse urban functions. This shift has created very strong functional and geographical mobility needs. In urban unplanned areas and / or remote from centers, local mobility grew through walk and horse-drawn transport. Movements leading to the centers for reasons of work, commerce, education or access to various services abound via motorized transport.Clearly, the relationship between transport and urban planning are ambivalent. If urban development precedes the transport network in the suburbs, elsewhere, it plays a major role in the structuring of urban areas, especially in the historic centers and along major highways.Yet this informal transport is operating outside the rules, it meets the mobility needs of many low-income users. Thus, it is making prominent the role of the government to regulate the transports sector.
94

Dav a masa v umění. Multiplicita v díle Ivana Kafky / Mass and Crowd. Multiplicity in works by Ivan Kafka

Bartlová, Anežka January 2013 (has links)
I have paid attention to artworks of Ivan Kafka especially to the problem of multiplicity. On the background of the reseach of Kafka's work I have described some aspects of his art work in more common way: dealing with time, with space and with multiplicity. I have shortly analyzed first two aspects. On the other hand is multiplicity much wider phenomena, I have defined with categories which were created specially for this work. The category of mass is defined by non-living unifique parts of one coplex without any autonomy. The second type labeled as crowd type, typically contains some level of individuality. On such background I tried to create a diagramatic structure, which was postulated according to Rolasind Krauss'es "expanded fields". This should better show the relations between terms like mass, crowd, seriality and serial type of multiplicity. I have also applied these categories on particular Ivan Kafka's artworks, but in the end I suggest to asser this system of multiplicity categories on other artists artworks as well.
95

Částice a pole v křivých prostoročasech (vybrané problémy) / Částice a pole v křivých prostoročasech (vybrané problémy)

Hejda, Filip January 2013 (has links)
In 2009 Bañados, Silk and West described the possibility of principally unbounded collision energies in the centre-of-mass frame for the particle collisions in the vicinity of black holes. Their work attracted a big response. This thesis aims to summarise the results of a number of the articles about the topic and puts these results into a new, broader context. It also presents some generalisations of the existing results, especially for models of magnetised black holes. The main subject of interest is the question, whether the unbounded collision energies can be achieved in a single-scattering or multiple-scattering process which was first formulated by Grib, Pavlov and Zaslavskii. Variety of methods is summarised. A considerable attention is paid to the limiting near-horizon description, which is further developed in order to derive new links and relations among known results, particularly between the purely theoretical work dealing with the geometry of degenerate horizons and their vicinity and more astrophysical articles about magnetic fluxes. Powered by TCPDF (www.tcpdf.org)
96

Diskuse o principu inherence / On the inherency priciple in contemporary Dutch

Kyslý, Martin January 2014 (has links)
The purpose of this thesis is to describe the phenomenon known as the Inherency Principle in the Dutch language from the perspective of a non-native speaker. The study focuses on research and analysis of how modern journalism incorporates grammatical rules, and specifically the application of the Inherency Principle within journalistic text. The study is based on a review of several newspaper articles from a range of news categories including current affairs; culture; comment; sport etc. The structure of the sentences within these texts is critically analysed and carefully assessed to identify if the practical use of language in journalism corresponds to the rules of the Inherency Principle as defined in The Algemene Nederlandse Spraakkunst (ANS). The ANS is considered to hold some of the most important and complex grammatical functions by both expert and non-native Dutch speakers. The Inherency Principle in particular is linked to a number of issues that are explored in this paper. The second chapter of the thesis outlines the theoretical basis of the Inherency Principle using two descriptive grammatical handbooks of the Dutch language, namely Algemene Nederlandse zin, by Haeseryn et. al. from 1997, and Grammatica van de Nederlandse zin, by Vandeweghe et. al. from 2004. The subsequent chapters...
97

Vývoj metody vizualizace a měření teplotních polí ve vzduchu pomocí termovize / Development of method for visualization and measuring of temperature fields in air with using thermovision camera

Pešek, Martin January 2014 (has links)
This work deals with the measurement of temperature fields in the air using an infrared camera. The dissertation describes the opportunity of measuring the temperature field in the air and the characterization of the developed measuring method. In the next part there are introduced the beginning of thermography imaging and the field of usability of the new infrared measuring method. Further, the theoretical foundations of the thermography measuring method in the temperature fields in the air are described. In the theoretic background there are described the analysis of heat conduction in an auxiliary material, the determination of dynamic properties of the method and the analysis of radiation, which has an influence on infrared imagining. This method requires an insertion of the auxiliary material into the non-isothermal air flow, which can allow for the study of the temperature distribution in air. For effective visualization of temperature fields in the air using an infrared camera, the selection of the appropriate auxiliary material, on which the air temperature displays, is crucial. In the next part of the doctoral thesis, there is a description of static measuring properties of auxiliary materials. The usability range of the measuring method is determined from these properties. In the thesis there are presented the description of the device for the measurement of 2D temperature fields in the air and the description of the measuring device for 3D measurements of temperature fields in the air using an infrared camera, which can also be used for measurements of temperature fields in small enclosed spaces through a viewing window. For the practical use of the method, the detailed methodology of measuring temperature fields in the air by an infrared camera was developed and its applicability was demonstrated on practice examples. The developed measuring method can be used in many areas of research and in practice.
98

Identification and Explanation of Regional Development Poles in Haiti

Noailles, Carline 14 May 2010 (has links)
The concentration of the population and socioeconomic activities in the Metropolitan Area of Port au Prince (MAPAP) in Haiti has a negative impact within MAPAP and on the socioeconomic development of the entire country. This phenomenon, known as urban primacy, is increasing at an unprecedented rate in developing countries. Urban primacy in the Third World is explained by scholars studying the phenomenon and by dependency theorists. Economic decentralization, based on growth pole theory, is one of the most frequently used policies for slowing the growth of primate cities by focusing on development poles. In Haiti, the potential growth poles are the regional capitals that have a constitutional mandate to promote and manage the development of their region. I have tested some of the assumptions of dependency and growth pole theories on Haiti, using the eight regional capitals as units of analysis. Using migration, geographic, and socioeconomic data, I have identified the strongest poles and explained their attraction power and formulated policy recommendations that will increase the chances of successfully implementing economic decentralization. The research design is the case study. The data show that MAPAP overshadows the regional capitals at the national level and within the capitals' own region, except for Cap Haïtien. However, the regional capitals are the primary destinations for migrants within their regions. The strongest poles are Cap Haïtien, Gonaives, and Port de Paix. Their attraction power is explained primarily by their population size and by their connections to the international market. Due to the selection criteria of the units of analysis and the limitations of the data used, the support and rejection of the growth pole and dependency theories hypotheses are not conclusive for the testing of these theories in Haiti or the Third World. The Haitian government needs to be more aggressive in addressing the consequences of urban primacy by implementing a comprehensive economic decentralization. The January 12, 2010, earthquake brought light on the issues raised by this study. Fortunately, the Haitian government has expressed its vision for the rebuilding of Haiti with an emphasis on decentralizing socioeconomic activities outside of MAPAP.
99

Test Plan for Real-Time Modeling & Simulation of Single Pole Switching Relays

Sanaboyina, Ram Mohan 13 May 2016 (has links)
A real-time simulator (RTS) with digital and analog input/output modules is used to conduct hardware-in-the-loop simulations to evaluate performance of power system equipment such as protective relays by exposing the equipment to the simulated realistic operating conditions. This work investigates the use of RTS to test relays with single-pole-switching (SPS) feature. Single-pole switching can cause misoperations due to fault arc during reclosing of the breakers. Through this investigation, a test procedure appropriate for the testing SPS relays has been developed. The test procedure includes power system modeling for real time simulation, relay test setup, and test plan. HYPERSIM real-time simulator was used to model an actual power system. Transmission lines, three-winding transformers, and induction motor were modeled with actual parameters. Models for fault arc in HYPERSIM real time simulator were developed. Test set-up for evaluating relay performance and wiring drawings for connecting relay in closed-loop to the simulator were developed.
100

Contribuição do SISCOM na investigação do blurring do polo temporal associado à atrofia hipocampal em pacientes com epilepsia do lobo temporal: um estudo com SPECT cerebral / Contribution of SISCOM in the investigation of temporal pole blurring in patients with temporal lobe rpilepsy and hippocampal atrophy: a brain SPECT study

Sonvenso, Daniele Kanashiro 04 March 2016 (has links)
Este foi um estudo retrospectivo de 18 pacientes com atrofia hipocampal (AH) e 21 pacientes com AH associada ao blurring do polo temporal (BPT), nos quais realizamos a investigação das alterações perfusionais ao SPECT (Single Photon Emission Computed Tomography) crítico, ao SPECT intercrítico e ao SISCOM (Subtraction Ictal SPECT Coregistered to MRI) e sua comparação com os dados de avaliação pré-cirúrgica. Os pacientes com BPT apresentaram início mais precoce da epilepsia, uma duração de epilepsia maior e um período maior de seguimento pós-operatório (PO). O padrão pefusional ipsilateral ao SPECT crítico, o qual denominamos de padrão -típico?, foi o padrão perfusional mais frequentemente encontrado em ambos os grupos de pacientes com e sem BPT. Ao SPECT intercrítico, a maioria dos pacientes com BPT apresentaram hipoperfusão ipsilateral no lobo temporal (LT) epileptogênico, enquanto que no grupo sem BPT esta hipoperfusão foi observada em metade dos pacientes. Ao SISCOM, o padrão perfusional -típico? foi novamente o mais encontrado em ambos os grupos com e sem BPT. Entretanto, os padrões considerados -atípicos? foram encontrados mais frequentemente nos pacientes com BPT, o que nos sugere um padrão de propagação das crises epilépticas discretamente diferente neste grupo com BPT, o qual envolve outras áreas dos LT bilateralmente. Contrariamente à nossa hipótese inicial, não encontramos associação entre a presença de BPT e a presença de hiperperfusão no polo temporal (PoT) seja ao SPECT crítico ou ao SISCOM. Por este achado, nossos dados não suportam a idéia de que o BPT seja resultado de alterações teciduais intercríticas secundárias a um maior envolvimento ou participação deste polo na geração ou propagação de crises epilépticas na epilepsia do lobo temporal (ELT) mesial. Por outro lado, nossos resultados sugerem que o PoT é uma região frequentemente envolvida pelas crises do LT. Particularmente, a hiperperfusão no PoT ipsilateral à AH ao SISCOM foi mais encontrada nos pacientes com casos clínicos típicos de ELT mesial, sugerindo que o PoT é mais frequentemente envolvido (um padrão típico) em crises epilépticas em casos clínicos com informações mais concordantes (clear cut) e sugestivas de ELT mesial unilateral / This was a retrospective study of 18 patients with hippocampal atrophy (HA) and 21 patients with HA associated to temporopolar blurring (TPB). We performed an investigation of perfusion changes of ictal single photon emission computed tomography (SPECT), interictal SPECT and subtraction ictal SPECT coregistered to magnetic resonance imaging (SISCOM) and its comparison with results of presurgical evaluation. Patients with TPB showed earlier epilepsy onset, longer duration of epilepsy and a longer period of post surgical follow-up. The ipsilateral perfusion pattern in the ictal SPECT, which we denominated -typical? pattern, was the most frequent in both groups of patients, with and wihout TPB. In the interictal SPECT, most of patients with TPB showed ipsilateral hypoperfusion to the epileptogenic temporal pole (TP), while in the group without TPB this hypoperfusion was observed in half of the patients. Through SISCOM, the typical perfusion pattern was the most frequent in both groups. However, the patterns considered -atypical? were found more frequently in patients with TPB, which suggests a pattern of propagation of epileptic seizures slightly different in the group with TPB, which involves other areas of TL bilaterally. Adversely to our hypothesis, we did not found association between the occurrence of TPB and the hyperperfusion in the TP neither in the ictal SPECT nor SISCOM. Based on this finding, our data does not support the idea that the BTP is a result of interictal secondary tissue changes due to a higher involvement or role of this pole in the generation or propagation of epileptic seizures in the mesial temporal lobe epilepsy (TLE). On the other hand, our results suggest that the TP is a region frequently involved by seizures of TL. Particularly, the hyperperfusion in the TP which is ipsilateral to the HA through SISCOM was the most found in patients with typical clinical cases of mesial TLE, suggesting that the TP is frequently involved (a typical pattern) in epileptic seizures of clinical cases with more concordant information (clearcut) and suggestive of unilateral mesial TLE

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