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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.
221

Individual dispersal decisions affect fitness via maternal rank effects in male rhesus macaques

Weiß, Brigitte M., Kulik, Lars, Ruiz-Lambides, Angelina V., Widdig, Anja January 2016 (has links)
Natal dispersal may have considerable social, ecological and evolutionary consequences. While speciesspecific dispersal strategies have received much attention, individual variation in dispersal decisions and its fitness consequences remain poorly understood. We investigated causes and consequences of natal dispersal age in rhesus macaques (Macaca mulatta), a species with male dispersal. Using long-term demographic and genetic data from a semi-free ranging population on Cayo Santiago, Puerto Rico, we analysed how the social environment such as maternal family, group and population characteristics affected the age at which males leave their natal group. While natal dispersal age was unrelated to most measures of group or population structure, our study confirmed earlier findings that sons of high-ranking mothers dispersed later than sons of low-ranking ones. Natal dispersal age did not affect males\\\'' subsequent survival, but males dispersing later were more likely to reproduce. Late dispersers were likely to start reproducing while still residing in their natal group, frequently produced extra-group offspring before natal dispersal and subsequently dispersed to the group in which they had fathered offspring more likely than expected. Hence, the timing of natal dispersal was affected by maternal rank and influenced male reproduction, which, in turn affected which group males dispersed to.
222

HIV-1 ENV: IMPACTING HIV-1 FITNESS, ENTRY INHIBITOR DRUG SENSITIVITY, AND IN VIVO SELECTION OF A RESISTANT VIRUS TO THE MICROBICIDE PSC-RANTES

Dudley, Dawn M. January 2008 (has links)
No description available.
223

The lateralisation of emotion in social mammals

Milligan, Adam D. S. January 2013 (has links)
The study of lateralisation has taken several forms ranging from investigating morphological asymmetries to research on lateralised motor and perceptual functions with many studies successfully evidencing lateralisation in a variety of species. This study, featuring three species (olive baboons, rhesus macaques, and spotted hyaenas) investigated visual field biases with the aim of determining whether emotional valence underpins these biases whilst also considering the influence of a number of other factors such as emotional intensity, age, sex, rank, and, for the first time, oestrus cycles (olive baboons only). This study aimed to establish whether Campbell’s (1982) Right Hemisphere Hypothesis or Silberman & Weingartner’s (1986) Valence Hypothesis offered the more valid theory for the lateralisation of emotion by considering interactions across the full spectrum of emotion – a question the almost exclusive investigation of negatively affective scenarios by previous studies has been unable to answer. Furthermore, this study provided a new methodology for investigating behavioural lateralisation by suggesting that separating the visual spectrum into five fields (extreme left, mid left, centre, mid right and extreme right) allows a more accurate insight into the lateralisation of visual perception than the traditional hemifield model. Finally, a more conservative method is proposed for analysing behavioural data in future studies from this field and suggests that these methods provide a more accurate representation of the lateralisation of emotion than those previously employed. A population-level left side bias was found for the spotted hyaenas, thus providing the first evidence of significantly lateralised behaviour in a large carnivore and, for this species at least, lending some support to Campbell’s (1982) Right Hemisphere hypothesis but as population-level biases were not found for either of the other species it may be premature to suggest this support is unequivocal. Significant age effects were found in two species as adult olive baboons and spotted hyaenas were both found to express significant left side biases. Spotted hyaenas were also found to express significant left side biases for females, dominant individuals, high intensity interactions, and sexual valence interactions whilst olive baboons expressed a significant left side bias during negative valence behaviours but no significant lateral biases were found in any context for rhesus macaques. In olive baboons behaviours performed by males and those of a low intensity were found to occur more frequently in the mid and central visual fields and neutral valence behaviours were less occurrent in the extreme visual fields whilst in spotted hyaenas sexual, positive and negative valence behaviours were significantly less centralised than neutral valence behaviours. Non-oestrus adult female olive baboons were significantly more strongly lateralised than in-oestrus females, thus suggesting an influence of sex hormones upon lateralisation that may also have been apparent from the hyaena data, particularly regarding the significant lateral biases observed for females and dominant individuals. Finally, this thesis discusses a number of methodological issues that were encountered during this study and provides recommendations for future research in this field. Namely, this thesis provides an updated method for calculating laterality bias that is much more suitable for species with binocular vision and details a novel method of assessing visual field preferences by considering central and peripheral visual fields as separate entities. Furthermore, this thesis suggests that the weighted method designed and implemented for this study provides a much more accurate methodological foundation for analyses which avoids the caveats that may have affected previous research and thus provides a considerably more robust template that should be encouraged for any similar subsequent studies.
224

Stratégies de reproduction des mâles et des femelles chez le macaque rhésus (Macaca mulatta)

Dubuc, Constance 12 1900 (has links)
Contrairement à d’autres groupes animaux, chez les primates, la hiérarchie de dominance ne détermine pas systématiquement le succès reproductif des mâles. Afin de comprendre pourquoi, j’ai étudié les stratégies de reproduction des mâles et des femelles dans un groupe de macaques rhésus de la population semi-libre de Cayo Santiago (Porto Rico), collectant des données comportementales, hormonales et génétiques pendant deux saisons de reproduction. Les résultats se résument en cinq points. 1. Les nouveaux mâles qui ont immigré dans le groupe d’étude occupaient tous les rangs les plus subordonnés de la hiérarchie de dominance et ont monté en rang suite au départ de mâles plus dominants. Ainsi, l’acquisition d’un rang supérieur s’est faite passivement, en absence de conflits. Par conséquent, les mâles dominants étaient généralement d’âge mature et avaient résidé plus longtemps dans le groupe que les mâles subordonnés. 2. L’accès des mâles aux femelles est en accord avec le « modèle de la priorité d’accès » selon lequel le nombre de femelles simultanément en œstrus détermine le rang de dominance du mâle le plus subordonné qui peut avoir accès à une femelle (p. ex. le mâle de rang 4 s’il y a quatre femelles en œstrus). Bien que les mâles dominants aient eu plus de partenaires et aient monopolisé les femelles de qualité supérieure (dominance, parité, âge) pendant leur période ovulatoire (identifiée grâce au profil hormonal de la progestérone), le rang de dominance n’a pas déterminé le succès reproductif, les mâles intermédiaires ayant engendré significativement plus de rejetons que prédit. Il est possible que ces jeunes adultes aient produit un éjaculat de meilleure qualité que les mâles dominants d’âge mature, leur donnant un avantage au niveau de la compétition spermatique. 3. Les mâles dominants préféraient les femelles dominantes, mais cette préférence n’était pas réciproque, ces femelles coopérant plutôt avec les mâles intermédiaires, plus jeunes et moins familiers (c.-à-d. courte durée de résidence). Au contraire, les femelles subordonnées ont coopéré avec les mâles dominants. La préférence des femelles pour les mâles non familiers pourrait être liée à l’attrait pour un nouveau bagage génétique. 4. L’intensité de la couleur de la peau du visage des femelles pendant le cycle ovarien était corrélée au moment de la phase ovulatoire, une information susceptible d’être utilisée par les mâles pour maximiser leur probabilité de fécondation. 5. Les femelles retiraient des bénéfices directs de leurs liaisons sexuelles. En effet, les femelles en liaison sexuelle bénéficiaient d’un niveau de tolérance plus élevé de la part de leur partenaire mâle lorsqu’elles étaient à proximité d’une source de nourriture défendable, comparativement aux autres femelles. En somme, bien que les mâles dominants aient bénéficié d’une priorité d’accès aux femelles fertiles, cela s’est avéré insuffisant pour leur garantir la fécondation de ces femelles parce que celles-ci avaient plusieurs partenaires sexuels. Il semble que l’âge et la durée de résidence des mâles, corrélats de leur mode d’acquisition du rang, aient confondu l’effet du rang de dominance. / In contrast to most animal groups, dominance hierarchy does not systematically determine male reproductive success in primates. In order to investigate why, I studied male and female reproductive strategies in a group of free-ranging rhesus macaques on Cayo Santiago, Puerto Rico. I collected behavioural, genetic, and hormonal data during two consecutive mating seasons. My results are summarized below. 1. All new males who immigrated into the study group occupied the lowest-ranking position in the dominance hierarchy and rose in rank as the higher-ranking males left the group. Achieving a higher dominance rank occurred passively, without physical conflict. Thus, dominant males were mature individuals who resided longest in the group. 2. Male access to oestrus females followed the predictions of the ‘priority of access’ model, in which the number of females in oestrus determines the rank of the lowest-ranking male who can access a female (e.g. the fourth ranking male if four females are in oestrus). Even though dominant males obtained more mating partners and monopolised higher quality females (dominance, parity, age) during the ovulation window (as identified using progesterone profiles), dominance rank did not determine reproductive success, as intermediate-ranking males sired significantly more infants than predicted. It is likely that those young, intermediate-ranking adult males produced high quality ejaculate, giving them an advantage in sperm competition. 3. Dominant males preferred high-ranking females, but this preference was not reciprocal; high-ranking females cooperated with younger and less familiar intermediate-ranking males. Conversely, subordinate females cooperated with dominant males. Female preference for non-familiar males (i.e. short residency in the group) may be explained by an attraction to a novel genetic pool. 4. Female facial color intensity during the ovarian cycle was correlated with the timing of the ovulation window. This information may be used by males in order to maximize their fertilisation probability. 5. Consort females enjoyed a higher level of tolerance from their male partner when they were in proximity to a monopolisable food source, compared to other, non-consort females. This suggests that females obtained direct benefits from their sexual consorts. In conclusion, even though dominant males had priority access to ovulating females in the group, this was insufficient to guarantee fertilisation when females had several sexual partners. It appears that males’ age and length of residency, both correlates of their rank acquisition mode, may have been confounding factors in dominance rank.
225

Evaluating The Kinetics Of Proinflammatory Immune Responses To Simian Immunodeficiency Virus Infection In Rhesus Macaques By Transcriptional Analysis

Unknown Date (has links)
Understanding the host response immediately following mucosal HIV-1 infection will be pivotal in determining whether the immune response induced by a vaccine will successfully sense and control viral replication. In order for effective vaccine strategies and modalities to be developed, these earliest immunological events must be fully assessed in a non-biased manner. Nonhuman primates (NHP), specifically Rhesus macaques (RM), serve as a model to investigate the immunological landscape immediately post-challenge and to define the spatiotemporal path of simian immunodeficiency virus (SIV). SIV infection of RM serves as a model of human HIV infection as it recapitulates many of the virological, immunological, and pathological features of HIV infection in the human host. In this thesis I will test the hypothesis whether transcriptional analysis will allow a sensitive measure of the early innate immune responses that accompany detection of the SIV virus in the periphery. I have determined that an early inflammatory profile arises early in tissues proximal to the challenge site that precedes widespread immune activation and the systemic antiviral interferon response. This study defines in detail the spatiotemporal relationship between virus and host immune response and may be a valuable resource in guiding future vaccine design strategies. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
226

Stratégies de reproduction des mâles et des femelles chez le macaque rhésus (Macaca mulatta)

Dubuc, Constance 12 1900 (has links)
Contrairement à d’autres groupes animaux, chez les primates, la hiérarchie de dominance ne détermine pas systématiquement le succès reproductif des mâles. Afin de comprendre pourquoi, j’ai étudié les stratégies de reproduction des mâles et des femelles dans un groupe de macaques rhésus de la population semi-libre de Cayo Santiago (Porto Rico), collectant des données comportementales, hormonales et génétiques pendant deux saisons de reproduction. Les résultats se résument en cinq points. 1. Les nouveaux mâles qui ont immigré dans le groupe d’étude occupaient tous les rangs les plus subordonnés de la hiérarchie de dominance et ont monté en rang suite au départ de mâles plus dominants. Ainsi, l’acquisition d’un rang supérieur s’est faite passivement, en absence de conflits. Par conséquent, les mâles dominants étaient généralement d’âge mature et avaient résidé plus longtemps dans le groupe que les mâles subordonnés. 2. L’accès des mâles aux femelles est en accord avec le « modèle de la priorité d’accès » selon lequel le nombre de femelles simultanément en œstrus détermine le rang de dominance du mâle le plus subordonné qui peut avoir accès à une femelle (p. ex. le mâle de rang 4 s’il y a quatre femelles en œstrus). Bien que les mâles dominants aient eu plus de partenaires et aient monopolisé les femelles de qualité supérieure (dominance, parité, âge) pendant leur période ovulatoire (identifiée grâce au profil hormonal de la progestérone), le rang de dominance n’a pas déterminé le succès reproductif, les mâles intermédiaires ayant engendré significativement plus de rejetons que prédit. Il est possible que ces jeunes adultes aient produit un éjaculat de meilleure qualité que les mâles dominants d’âge mature, leur donnant un avantage au niveau de la compétition spermatique. 3. Les mâles dominants préféraient les femelles dominantes, mais cette préférence n’était pas réciproque, ces femelles coopérant plutôt avec les mâles intermédiaires, plus jeunes et moins familiers (c.-à-d. courte durée de résidence). Au contraire, les femelles subordonnées ont coopéré avec les mâles dominants. La préférence des femelles pour les mâles non familiers pourrait être liée à l’attrait pour un nouveau bagage génétique. 4. L’intensité de la couleur de la peau du visage des femelles pendant le cycle ovarien était corrélée au moment de la phase ovulatoire, une information susceptible d’être utilisée par les mâles pour maximiser leur probabilité de fécondation. 5. Les femelles retiraient des bénéfices directs de leurs liaisons sexuelles. En effet, les femelles en liaison sexuelle bénéficiaient d’un niveau de tolérance plus élevé de la part de leur partenaire mâle lorsqu’elles étaient à proximité d’une source de nourriture défendable, comparativement aux autres femelles. En somme, bien que les mâles dominants aient bénéficié d’une priorité d’accès aux femelles fertiles, cela s’est avéré insuffisant pour leur garantir la fécondation de ces femelles parce que celles-ci avaient plusieurs partenaires sexuels. Il semble que l’âge et la durée de résidence des mâles, corrélats de leur mode d’acquisition du rang, aient confondu l’effet du rang de dominance. / In contrast to most animal groups, dominance hierarchy does not systematically determine male reproductive success in primates. In order to investigate why, I studied male and female reproductive strategies in a group of free-ranging rhesus macaques on Cayo Santiago, Puerto Rico. I collected behavioural, genetic, and hormonal data during two consecutive mating seasons. My results are summarized below. 1. All new males who immigrated into the study group occupied the lowest-ranking position in the dominance hierarchy and rose in rank as the higher-ranking males left the group. Achieving a higher dominance rank occurred passively, without physical conflict. Thus, dominant males were mature individuals who resided longest in the group. 2. Male access to oestrus females followed the predictions of the ‘priority of access’ model, in which the number of females in oestrus determines the rank of the lowest-ranking male who can access a female (e.g. the fourth ranking male if four females are in oestrus). Even though dominant males obtained more mating partners and monopolised higher quality females (dominance, parity, age) during the ovulation window (as identified using progesterone profiles), dominance rank did not determine reproductive success, as intermediate-ranking males sired significantly more infants than predicted. It is likely that those young, intermediate-ranking adult males produced high quality ejaculate, giving them an advantage in sperm competition. 3. Dominant males preferred high-ranking females, but this preference was not reciprocal; high-ranking females cooperated with younger and less familiar intermediate-ranking males. Conversely, subordinate females cooperated with dominant males. Female preference for non-familiar males (i.e. short residency in the group) may be explained by an attraction to a novel genetic pool. 4. Female facial color intensity during the ovarian cycle was correlated with the timing of the ovulation window. This information may be used by males in order to maximize their fertilisation probability. 5. Consort females enjoyed a higher level of tolerance from their male partner when they were in proximity to a monopolisable food source, compared to other, non-consort females. This suggests that females obtained direct benefits from their sexual consorts. In conclusion, even though dominant males had priority access to ovulating females in the group, this was insufficient to guarantee fertilisation when females had several sexual partners. It appears that males’ age and length of residency, both correlates of their rank acquisition mode, may have been confounding factors in dominance rank.
227

Inferring social structure and dominance relationships between rhesus macaques using RFID tracking data

Maddali, Hanuma Teja 22 May 2014 (has links)
This research address the problem of inferring, through Radio-Frequency Identification (RFID) tracking data, the graph structures underlying social interactions in a group of rhesus macaques (a species of monkey). These social interactions are considered as independent affiliative and dominative components and are characterized by a variety of visual and auditory displays and gestures. Social structure in a group is an important indicator of its members’ relative level of access to resources and has interesting implications for an individual’s health. Automatic inference of the social structure in an animal group enables a number of important capabilities, including: 1. A verifiable measure of how the social structure is affected by an intervention such as a change in the environment, or the introduction of another animal, and 2. A potentially significant reduction in person hours normally used for assessing these changes. The behaviors of interest in the context of this research are those definable using the macaques’ spatial (x,y,z) position and motion inside an enclosure. Periods of time spent in close proximity with other group members are considered to be events of passive interaction and are used in the calculation of an Affiliation Matrix. This represents the strength of undirected interaction or tie-strength between individual animals. Dominance is a directed relation that is quantified using a heuristic for the detection of withdrawal and displacement behaviors. The results of an analysis based on these approaches for a group of 6 male monkeys that were tracked over a period of 60 days at the Yerkes Primate Research Center are presented in this Thesis.
228

Diffusion tensor imaging at long diffusion time

Rane, Swati 30 June 2009 (has links)
Diffusion Tensor Imaging (DTI) is a well-established magnetic resonance technique that can non-invasively interpret tissue geometry and track neural pathways by sampling the diffusion of water molecules in the brain tissue. However, it is currently limited to tracking large nerve fiber bundles and fails to faithfully resolve thinner fibers. Conventional DTI studies use a diffusion time, t[subscript diff] of 30 ms - 55 ms for diffusion measurements. This work proposes the use of DTI at long t[subscript diff] to enhance the sensitivity of the method towards regions of low diffusion anisotropy and improve tracking of smaller fibers. The Stimulated Echo Acquisition Mode (STEAM) sequence was modified to allow DTI measurements at long t[subscript diff] (approximately 200 ms), while avoiding T2 signal loss. For comparison, DTI data was acquired using STEAM at the shorter value of t[subscript diff] and with the standard Double Spin Echo sequence with matched signal-to-noise ratio. This approach was tested on phantoms and fixed monkey brains and then translated to in vivo studies in rhesus macaques. Qualitative and quantitative comparison of the techniques was based on fractional anisotropy, diffusivity, three-phase plots and directional entropy. Tensor-field maps and probabilistic connectivity fronts were evaluated for all three acquisitions. Comparison of the tracked nerve pathways showed that fibers obtained at long t[subscript diff] were much longer. Further, the optic tract was tracked in ex vivo fixed rhesus brains for cross validation. The optic tract, traced at long t[subscript diff], conformed to the well documented anatomical description, thus confirming the accuracy of tract tracing at long t[subscript diff]. The benefits of DTI at long t[subscript diff] indeed help to realize the potential of tensor based tractography towards studying neural development and diagnosing neuro-pathologies, albeit the improvement is more significant ex vivo than in vivo.
229

Metagenomics in One Health — from standardization to targeted application

Hallmaier-Wacker, Luisa 10 May 2019 (has links)
No description available.
230

Non-human primate iPS cells for cell replacement therapies and human cardiovascular disease modeling

Rodriguez Polo, Ignacio 29 October 2019 (has links)
No description available.

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