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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

Male-infant interactions in wild crested black macaques, Macaca nigra

Kerhoas, Daphne 15 November 2016 (has links)
Direct fitness is measured as the number of surviving offspring. Thus adult males may try to produce as many offspring as possible or to increase the survival of their offspring. Recent findings have shown the many potential benefits of fathers’ presence and support on infants’ development and survival. However, little is known about the influence of socio-ecological factors on male-infant interactions. The main aim of this thesis was therefore to investigate male-infant interactions in wild crested macaques (Macaca nigra). In particular, we aimed to examine the affiliative and agonistic interactions taking place in this species, along with the factors influencing these interactions and offspring survival. Data collection for this thesis took place in the Tangkoko-Duasudara Reserve in Sulawesi, Indonesia, on 3 wild groups of crested macaques. For the first study, data were collected on migrations, births, disappearances, and encounters between groups over 5 years. We analyzed the influence of socio-ecological factors (e.g. rainfall, alpha-male position takeover, and male hierarchy stability) on pre- and post-natal loss. The results showed that high infant mortality was mainly associated to male alpha-position takeover, which suggests that infanticide may indeed occur in this species. In addition, we found that female within-group competition for food sources and between-group resource defense influenced fetal and infant loss. Based on these findings, we were interested to see whether fathers protected their own offspring against male attacks. Thus, in the second study, we investigated the social determinants and characteristics of male-infant affiliations. Our results indicate that adult males and infants form preferential association, and that infants initiate the majority of male-infant affiliations. Infants initiated affiliations mainly towards a high ranking male or a male in a close relationship with their mother. In addition, infants affiliated mainly with adult males in the absence of their mother, while males affiliated mostly with infants when the infants‘ mother was present in proximity. Furthermore, males initiated affiliations towards an infant when they held a high rank or when they had a strong bond with the infant‘s mother. Interestingly, paternity did not affect male-infant affiliations. In conclusion, these studies provide insights in the specifics of both infant survival strategies and male reproductive strategies. In addition, we show that infants are active agents in establishing and maintaining preferential relationships with males. This thesis, thus, confirm that male-infant interactions, although rare, have a strong influence both on males’ and infants’ direct fitness.:Contents ........................................................................................................................................ 5 List of Figures .............................................................................................................................. 7 List of Tables ................................................................................................................................ 8 Summary ....................................................................................................................................... 9 Zusammenfassung .................................................................................................................. 13 1 General Introduction .......................................................................................................... 17 1.1 Infants and adult males in mammals ...................................................................... 18 1.2 Primate males’ use and abuse of infants ................................................................ 19 1.3 Male care and paternal care in primates ............................................................... 20 1.4 Crested macaques as study species ......................................................................... 21 1.5 Aims of this thesis ........................................................................................................... 23 2 Social and ecological factors influencing offspring survival in wild macaques ................................................................................................................................... 25 2.1 Abstract ............................................................................................................................... 26 2.2 Introduction ...................................................................................................................... 26 2.3 Methods .............................................................................................................................. 29 2.4 Results ................................................................................................................................. 34 2.5 Discussion .......................................................................................................................... 37 3 Mother-male bond, but not paternity, influences male-infant affiliation in wild crested macaques .......................................................................................................... 45 3.1 Abstract ............................................................................................................................... 46 3.2 Introduction ...................................................................................................................... 46 3.3 Methods .............................................................................................................................. 50 3.4 Results ................................................................................................................................. 58 3.5 Discussion .......................................................................................................................... 61 4 Thesis Conclusion ................................................................................................................ 71 Appendices ................................................................................................................................ 75 Supplementary figure and tables for Chapter 2 ......................................................... 76 Supplementary methods and tables for Chapter 3 ................................................... 79 Bibliography ............................................................................................................................. 83 Acknowledgements ................................................................................................................ 99 Contributions of co-authors .............................................................................................. 101 Curriculum vitae .................................................................................................................... 105 Publications and conference contributions ................................................................. 107 Selbstständigkeitserklärung ............................................................................................. 109
92

4th PhD conference: Sustainability? - Your research - our world ; Abstracts

Zienert, Tilo 03 February 2020 (has links)
These are the abstracts of the oral and poster presentations of the 4th PhD conference held on 06. June 2019 in Freiberg.
93

Competing magnetic interactions in 4F-Based magnets studied by neutron scattering

Nikitin, Stanislav 22 July 2020 (has links)
The document is the PhD thesis of Stanislav Nikitin. It summarizes results of the comprehensive investigation of the magnetic fluctuations in several quantum magnets by means of elastic and inelastic neutron scattering.
94

Undergraduates' Knowledge and Interest in the Doctorate of Philosophy Degree for Communication Sciences and Disorders

Witter, Elizabeth Ashlee 14 November 2011 (has links)
No description available.
95

Rise Up: Exploring the First Year Experiences of Latina Doctoral Students at Predominantly White Institutions

Pecero, Veronica Flores January 2016 (has links)
No description available.
96

Syntheses and investigations of 2,6-dideoxysugars contained in diverse bioactive compounds

Mendlik, Matthew T. 10 August 2005 (has links)
No description available.
97

Macroparasite transmission and dynamics in Apodemus flavicollis

Ferrari, Nicola January 2005 (has links)
This thesis examines the parasite dynamics and the mechanisms affecting parasite load and transmission focalising on the role played by host and habitat heterogeneities. This study is based on the gastrointestinal nematode Heligmosomoides polygyrus and the small mammal yellow necked mouse and uses data gathered from experimental field manipulations of parasites intensities and data gathered from trapping monitoring. Initially the parasite community of yellow-necked mouse (Apodemus flavicollis) was explored in North-Eastern Italian Alps with the aim to describe the major patterns and identify the factors affecting parasite community structure. Despite the observed spatial variability it has been found that differences within the host population such age and secondly sex and breeding conditions, were the major factors acting on parasite occurrence and intensity. Habitat differences had a less apparent effect on parasite community structure. The consequences of H. polygyrus infection on other parasite species infections have been analysed, in specific the infestation of the tick Ixodes ricinus in populations of A. flavicollis. H. polygyrus load and tick infestation were monitored as well as were carried out field manipulations of H. polygyrus intensity and were monitored changes in tick infestation. It has been found that H. polygyrus load was negatively related to I. ricinus infestations. Host factors mediated the H. polygyrus-I. ricinus interaction such that young and non-breeding mice exhibited higher I. ricinus to H. polygyrus intensity respect breeding adults. The role of host sex on parasite abundance was then investigated carrying out a field experiment where the H. polygyrus intensity were manipulated in relation to mice gender. In specific, H. polygyrus was removed alternately from either sexes and the parasite load was analysed in the untreated sex. It was found that males mice were responsible to drive parasite transmission in the host population and this was observed in absence of sex-bias in parasite infection, suggesting that this pattern was not a mere consequence of quantitative differences in parasite loads between sexes. To disentangle the possible mechanism causing this sex bias in parasite transmission mathematical simulations based on parameters obtained for the field experiment were used. Two non mutually exclusive hypotheses causing sex bias in parasite transmission were tested: a- males immune response is less efficient and this causes the development of more successful parasite infective stages or b-males behaviours allow them to be more efficient is spreading in more exposed areas parasite infective stages. Multi-host models were developed and simulations were compared with field results. While it was not disentangled the most dominant mechanism causing sex bias in parasite transmission this study underlined the importance of host sexes in affecting parasite dynamics and host-parasite interaction. In conclusion this thesis highlighted the importance of considering host and environmental differences when investigating host parasite interactions. This finding could be extremely important when planning measured of disease control or to avoid disease outbreak. Controlling target group of individuals host could avoid economical losses and a more effective measure of intervention.
98

Méthodes conjointes de détection et suivi basé-modèle de cibles distribuées par filtrage non-linéaire dans les données lidar à balayage / Joint detection and model-based tracking methods of extended targets in scanning laser rangefinder data using non-linear filtering techniques

Fortin, Benoît 22 November 2013 (has links)
Dans les systèmes de perception multicapteurs, un point central concerne le suivi d'objets multiples. Dans mes travaux de thèse, le capteur principal est un télémètre laser à balayage qui perçoit des cibles étendues. Le problème desuivi multi-objets se décompose généralement en plusieurs étapes (détection, association et suivi) réalisées de manière séquentielle ou conjointe. Mes travaux ont permis de proposer des alternatives à ces méthodes en adoptant une approche "track-before-detect" sur cibles distribuées qui permet d'éviter la succession des traitements en proposant un cadre global de résolution de ce problème d'estimation. Dans une première partie, nous proposons une méthode de détection travaillant directement en coordonnées naturelles (polaires) qui exploite les propriétés d'invariance géométrique des objets suivis. Cette solution est ensuite intégrée dans le cadre des approches JPDA et PHD de suivi multicibles résolues grâce aux méthodes de Monte-Carlo séquentielles. La seconde partie du manuscrit vise à s'affranchir du détecteur pour proposer une méthode dans laquelle le modèle d'objet est directement intégré au processus de suivi. C'est sur ce point clé que les avancées ont été les plus significatives permettant d'aboutir à une méthode conjointe de détection et de suivi. Un processus d'agrégation a été développé afin de permettre une formalisation des données qui évite tout prétraitement sous-optimal. Nous avons finalement proposé un formalisme général pour les systèmes multicapteurs (multilidar, centrale inertielle, GPS). D'un point de vue applicatif, ces travaux ont été validés dans le domaine du suivi de véhicules pour les systèmes d'aide à la conduite. / In multi-sensor perception systems, an active topic concerns the multiple object tracking methodes. In this work, the main sensor is a scanning laser rangefinder perceiving extended targets. Tracking methods are generally composed of a three-step scheme (detection, association and tracking) which is jointly or sequentially implemented. This work proposes alternative solutions by considering a track-before-detect approach on extended targets. It avoids the classic procedures by proposing a global framework to solve this estimation problem. Firstly, we propose a detection method dealing with measurements in natural coordinates (polar) which is founded on geometrical invariance properties of the tracked objects. This solution is then integrated in the JPDA and PHD multi-target tracking frameworks solved with the sequential Monte-Carlo methods. The second part of this thesis aims at avoiding the detection step to propose an approach where the object model is directly embedded in the tracking process. This lets to build a novel joint detection and tracking approach. An aggregation process was developed to construct a measurement modeling avoiding any suboptimal preprocessing. We finally proposed a general framework for multi-sensor systems ( multiple lidar, inertial sensor, GPS). Theses methods were applied in the area of multiple vehicle tracking for the Advanced Driver Assistance Systems.
99

Obten??o dos par?metros-x de estruturas planares

Nascimento, Pedro Ivo de Araujo do 11 December 2012 (has links)
Made available in DSpace on 2014-12-17T14:56:12Z (GMT). No. of bitstreams: 1 PedroIAN_DISSERT.pdf: 1986241 bytes, checksum: 386b7b9f50f9765c6f2575f4e58ea4e5 (MD5) Previous issue date: 2012-12-11 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Due to major progress of communication system in the last decades, need for more precise characterization of used components. The S-parameters modeling has been used to characterization, simulation and test of communication system. However, limitation of S-parameters to model nonlinear system has created new modeling systems that include the nonlinear characteristics. The polyharmonic distortion modeling is a characterizationg technique for nonlinear systems that has been growing up due to praticity and similarity with S-parameters. This work presents analysis the polyharmonic distortion modeling, the test bench development for simulation of planar structure and planar structure characterization with X-parameters / O grande desenvolvimento dos sistemas de comunica??o nas ?ltimas d?cadas trouxe a necessidade de uma caracteriza??o cada vez mais precisa dos componentes utilizados. A modelagem por meio de par?metros-S ? utilizada para caracteriza??o, simula??o e testes de sistemas de comunica??o desde meados dos anos 60. Contudo a limita??o dos par?metros-S para sistemas lineares fez crescer a necessidade por novos tipos de parametriza??es que incluam as caracter?sticas de sistemas n?o lineares. A modelagem por distor??o poli-harm?nica ? uma t?cnica de caracteriza??o aplicada a sistemas n?o lineares que vem ganhando espa?o na literatura por sua praticidade e semelhan?a conceitual com os par?metros-S. Este trabalho apresentar? uma an?lise da modelagem por distor??o harm?nica, o desenvolvimento de um banco de testes para simula??o de estruturas planares e a caracteriza??o destas estruturas por meio de par?metros-X. Com isso pretende-se analisar a utiliza??o, precis?o e efici?ncia da modelagem por distor??o poli-harm?nica para estruturas planares
100

Um estudo sobre o processo que desencadeou o doutoramento de Joaquim Gomes de Sousa (1829-1864) e alguns apontamentos sobre sua tese /

Mariotto, Rachel January 2019 (has links)
Orientador: Sergio Roberto Nobre / Resumo: Joaquim Gomes de Sousa (1829-1864) ficou por muito tempo conhecido como o maior matemático brasileiro, tanto por seu modo inabitual de conseguir o grau de bacharel, quanto por sua tese de doutorado, ambos obtidos em 1848. Buscando retomar esse personagem da História da Matemática brasileira, por meio de um estudo documentado, este trabalho tem como foco os processos que desencadearam o doutoramento de Joaquim Gomes de Sousa (1829-1864), todos os processos relacionados a entrega de sua tese e um primeiro estudo da mesma. Para tal, foram realizadas buscas em diversos acervos, com destaque para o Arquivo Nacional, a Biblioteca de Obras Raras do Centro de Tecnologia da UFRJ e a Hemeroteca Nacional da Biblioteca Nacional. A partir das fontes encontradas, procedeu-se dois tipos de análise documental: indiciária e comparativa. Com a primeira, foi possível confirmar e descobrir novos fatos desde a obtenção de seu título de bacharel pela Escola Militar, mesmo sem ter esse personagem frequentado tal instituição, até a entrega de sua tese e colação do grau de doutor. Usando um método comparativo, estudou-se a tese de Gomes de Sousa destacando partes de seu conteúdo em relação ao que foi anteriormente desenvolvido por Laplace e Le Verrier. Para de uma revisão bibliográfica a respeito do, Através dessas análises foi possível compreender sua importância dentro do contexto científico da época, e ainda esclarecer alguns mitos que abordavam a história do personagem. Além disso, esse trabalho ... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

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