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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.

Rhythmic behaviour of coastal crustaceans

Warman, Clifford Guy January 1990 (has links)
No description available.

Dispersal in highly fragmented water vole (Arvicola terrestris) populations

Tedesco, Edoardo January 2010 (has links)
The water vole (<i>Arvicola terrestris</i>) is a microtine that occurs naturally in highly fragmented populations, which persist as metapopulations. Here, I investigate two metapopulations consisting of 183 habitat patches in two areas.  The aim of this thesis is to investigate the factors that determine the dispersal decisions of individuals.  Specifically, I examined 1) the ecological characteristics of the natal patch that underlie the emigration decision of an individual, 2) the characteristics of intermediate patches encountered during dispersal that affect dispersal distance; 3) differences in fitness between dispersing and philopatric individuals.  Findings were: 1) Dispersal rate was high with no sex bias.  The probability of a female dispersing was influenced by the presence of other females.  There was a greater probability of males immigrating into larger patches with less related individuals thus leading to inbreeding avoidance.  2) Individuals settle at different distances from the natal patch.  There was a negative relationship between dispersal distance and number of patches with opposite sex conspecifics.  There was a higher probability of males immigrating into a patch if there were other adult females.  For females, the probability of dispersing into a patch was proportional to the number of adults present in that patch.  The results suggest that individuals sample patches before settling.  3) There were no differences in fitness between immigrating and philopatric individuals. These results suggest that individuals distribute themselves in the metapopulation according to the patch carrying capacity to maximize their own fitness. These findings are discussed in relation to the dynamics and persistence of metapopulations and consequences for fragmented populations in general.

Animal minds : the empirical foundations of the interests of animals

Bell, Mark Cameron. 10 April 2008 (has links)
In this thesis, I submit an empirical method for assessing the interests of non-human animals. This method involves attributing interests to animals on the basis of the choices they make between competing commodities/environments and by gauging the amount of energy they are willing to expend in acquiring these alternatives. Outfitted with consumer demand theory I argue that this method not only determines what an animal wants, it also reveals the commodities that the animal judges to be indispensable to its welfare.

Sociality in the African woodland dormouse

Madikiza, Zimkitha Josephine January 2017 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in fulfilment of the requirements for the degree of Doctor of Philosophy 2017 / Social systems describe the social organisation, mating system and social interactions of a species, and are revealing of the nature of how animals live and the underlying mechanisms of living alone or in groups. The social system of the African woodland dormice Graphiurus murinus has not been documented. The aim of my study was to investigate sociality, the mechanisms promoting sociality, and to G. murinus along the continuum of sociality in respect of rodents. Investigations on nest sharing in free-living woodland dormice showed that sleeping associations were common in females than males but changed seasonally (females all year round; males in breeding and winter seasons), reflecting the reproductive and thermoregulatory needs. The social structure of these sleeping associations was assessed using association indices and social network analysis. Woodland dormice exhibited a web of relationships between sex and age groups, with adult female groups and juvenile groups forming strong and exclusive relationships, while male groups showed ephemeral and weak relationships. In staged dyadic encounters of same sex dyads in captivity, females were amicable and tolerated unfamiliar females, whereas males displayed low tolerance and aggression towards unfamiliar. The three-chamber paradigm tests for sociability and social preferences revealed that both adult males and females had an intrinsic motivation to be social. However, this motivation differed by sex, with females showing a greater affinity for both strangers and unfamiliar females, whereas males showed an affinity for familiar males. Observations of huddling in female dyads revealed that, under decreasing Ta, females huddled together and combined nest material, thus changing the local microclimate and the insulation capacities of nests. In addition, long-associations were maintained even after Ta was increased, revealing that thermal challenges might promote group formation and enhance familiarity amongst females. Both my field and laboratory data suggest that woodland dormice form small seasonally transient sleeping associations. In females, limited aggression, tolerance, and nest sharing and construction under low temperatures could also lead to prolonged group-living. In males, aggression towards unfamiliar males, possibly maintains intra-sexual territoriality, yet familiarity creates tolerance, leading to group-living. Group-living in this arboreal rodent is mediated by the apparently phylogenetically constrained energetic demands of thermoregulation, coupled with an inherent need to associate with conspecifics. The level of familiarity between conspecifics or the presence of social partners facilitates group formation and is shaped by prevailing ecological conditions. / MT 2017

The pet in contemporary art

Pretorius, Elmarie 23 June 2011 (has links)
MA (Fine Art), Faculty of Humanities, University of the Witwatersrand, 2011 / The purpose of this paper is to investigate the figure of the pet in contemporary art. I will argue that the pet offers rich potential for creative exploration that challenges the conventional binaries of self/other, human/animal, and tame/wild in a way that tries to speak of a different subjectivity. I take as a starting point that the pet is seen as not other enough and this explains its relative absence in contemporary visual art practice and discourse. Currently there is a lot of interest in the animal within this field, but the animal is usually cast as wild or untamed – all too often functioning as a signifier of difference from the human (through this difference, of course, we define what is human). For all that the pet is an animal it does not serve as a signifier in the same way. It straddles binaries/boundaries of human/animal and even self/other in a manner that is often interpreted as ‘uncomfortable’. I will argue that the widespread prejudice against pets is based on a very deep seated and problematic formulation of the wild, and if the binary opposition of the wild and the domestic is discarded (as the binary opposition of the human and the animal was/is) the pet is more than equal to the same theoretical, and consequently practical, burden as the wild animal. With special attention to the concept of becoming-animal, outlined by Deleuze and Guattari, I look at the artists Jo Ractliffe, Carolee Schneemann, and William Wegman whose pets play a pivotal role in the production of their artworks, and in some cases, the trajectory of their careers. I contend that within this cross-species relationship/experience/void/communication (or any other description one might hazard to apply) something happens, an event, something meaningful, worth consideration. The very nature of a cross-species phenomenological, libidinal relating is, for me, laden with creative possibility. I argue that the pet has the potential to open up a creative space within which important and topical issues, anxieties and subject fractures can be visually manifested

The skull and mandible of the South African baboon.

Trevor-Jones, Trevor Rubidge January 1975 (has links)
This Thesis is submitted to the University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Surgery. The examination for this degree was completed in 1947. / The skull and mandible of the baboon. This is a morphological study of the skulls and mandibles of 102 specimens from known localities in Southern Africa. A detailed reference book on the anatomy of the baboon is particularly important because of the increasing use of this animal in medical science. The skulls and mandibles of captive animals are referred to but are not included in the comparative study since animals in captivity are subject to dietetic disturbances and other factors not yet fully understood. The cranium of an adult male skull is described in all normae. Comparisons are made with the crania of seven adult male baboons from widely separated known localities. This study shows that two main craniofacial types, with intermediate types, occur among the crania of South African baboons. Type 1. crania have small maxillary ridges, shallow maxillary fossae, ventrally directed zygomatic bones, large ventral orbital apertures, well developed superciliary ridges, high temporal lines and sagittal crests. Type 11. crania have large flared maxillary ridges, deep maxillary fossae, ventrolateral ly directed zygomatic bones, small ventral orbital apertures, large supraorbital tori, low temporal lines and no sagittal crests. This apparent1y supports the specific and subspecific claims of some observers. However, a critical examination of the crania of six adult female baboons from the same troop at Bindura, Rhodesia, shows that similar craniofacial types occur among female baboons. It is possible to associate mandibular types with the craniofacial types in adult male baboons. This is not the case with female baboon mandibles. / WHSLYP2017

A qualitative and quantitative study of the somnogenic neural systems in the brains of cetaceans and closely related species

Dell, Leigh-Anne 16 September 2015 (has links)
A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfillment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2015 / Cetaceans show an unusual form of mammalian sleep, with unihemispheric slow waves (USWS), suppressed REM sleep and continuous bodily movement, however the mechanism by which USWS occurs is unclear. This thesis describes the detailed anatomy of the neural systems systems involved in the control and regulation of sleep in the basal forebrain, diencephalon, midbrain and pons in three Cetartiodactyla species namely the Harbour porpoise, Northern minke whale and the Hippopotamus, as well as a broader study of the orexinergic system in Cetartiodactyls by means of immunohistochemistry and stereological analysis. All the neural elements involved in sleep regulation and control found in bihemispheric sleeping mammals were present in the harbour porpoise, minke whale and hippopotamus with no specific nuclei being absent, and the only novel nuclei being identified was the parvocellular orexinergic cluster in the hypothalamus- a feature seen in cetartiodactyla and the Africa elephant. This qualitative similarity of nuclear organization relates to the cholinergic, noradrenergic, serotonergic and orexinergic systems and is extended to the GABAergic elements involved with these nuclei. Quantitative analysis of the cholinergic and noradrenergic nuclei of the pontine region and the orexinergic nuclei of the hypothalamus revealed that in comparison to other mammals, the numbers of pontine cholinergic, noradrenergic and orexinergic neurons are markedly higher in the harbour porpoise and minke whale than in other large-brained bihemispheric sleeping mammals previously examined. Furthermore, the diminutive telencephalic commissures (anterior commissure, corpus callosum and hippocampal commissure) along with an enlarged posterior commissure and supernumerary pontine cholinergic and noradrenergic neurons in cetaceans indicate that the control of unihemispheric slow wave sleep is likely to be a function of interpontine competition, facilitated through the posterior commissure, in response to unilateral telencephalic input related to the drive for sleep. In addition, an expanded peripheral division of the dorsal raphe nuclear complex appears likely to play a role in the suppression of REM sleep in cetaceans. Thus, this thesis provides several clues to the understanding of the neural control of the unusual sleep phenomenology present in cetaceans

Some biochemical aspects of the motility of spermatozoa.

January 1979 (has links)
by Will W.M. Lee. / Thesis (M.Phil.) - Chinese University of Hong Kong. / Bibliography: leaves 101-110. / Chapter CHAPTER I --- GENERAL INTRODUCTION / Chapter A --- Spermatogenesis --- p.1 / Chapter B --- Sperm Maturation --- p.2 / Chapter C --- Ejaculation --- p.3 / Chapter D --- Sperms in Fertilization --- p.3 / Chapter E --- Aim of Spermatozoal Motility Studies --- p.7 / Chapter CHAPTER II --- AN ASSAY TO MEASURE THE SPERMATOZOAL PROGRESSIVE MOTION / INTRODUCTION --- p.8 / MATERIALS AND METHODS --- p.15 / Chapter A --- Sample Collection --- p.15 / Chapter B --- Cell Wash --- p.17 / Chapter C --- Media --- p.18 / Chapter D --- Motility Assay Chamber --- p.18 / RESULTS AND DISCUSSIONS --- p.22 / Chapter A --- Sperm Entry --- p.22 / Chapter B --- Sperm Motility --- p.32 / Chapter CHAPTER III --- EFFECT OF VARIOUS GROUPS OF CHEMICALS ON THE MOTILITY OF SPERMATOZOA / INTRODUCTION --- p.48 / MATERIALS AND METHODS --- p.55 / RESULTS AND DISCUSSIONS --- p.57 / Chapter A --- Energy Source --- p.57 / Chapter B --- "Phosphodiesterase Inhibitors and Cyclic 3',5'-Adenosine Monophosphate (cAMP)" --- p.59 / Chapter C --- p-Nitrophenyl Compounds --- p.64 / Chapter D --- Motility of Spermatozoa from Addicted Rat and Effect of Morphine on tozoa In VitroSperma- --- p.68 / Chapter E --- Metallic Ions and EDTA --- p.68 / Chapter CHAPTER IV --- EFFECT OF SEMINAL PLASMA ON SPERM MOTILITY --- p.77 / INTRODUCTION / MATERIALS AND METHODS --- p.79 / RESULTS --- p.82 / DISCUSSIONS --- p.98 / REFERENCES --- p.101 / Chapter APPENDIX I --- Spermatozoa Repellent as a Contraceptive --- p.111 / Chapter APPENDIX II --- Effect of p -Nitrophenylglycerol on Motility of Rat Epididymal Spermatozoa --- p.117

Modulation of 3H-thymidine incorporation in rat lymphocytes by adrenergic drugs.

January 1987 (has links)
by Lau Lit Fui. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 106-117.

An Anscombean approach to animal agency

Cash, Luke January 2019 (has links)
The ultimate aim of this thesis is to explain how the theory of action found in Anscombe's Intention can be modified to deliver a plausible account of non-human animal agency (henceforth, animal agency). More specifically, it is an attempt to develop her account in a way that respects the Aristotelian insight that animals act in ways that differ, in certain fundamental respects, from the processes of growth and self-maintenance found in plants, on the one hand, and the self-conscious actions characteristic of mature human beings, on the other. The negative aim is to show that the theory of action that constitutes the received backdrop in the study of animal minds is ill-suited for the task. This is what I call the Standard Approach to Animal Agency and, despite its widespread acceptance in comparative psychology, cognitive ethology, and the philosophy of animal minds, I argue that it faces serious problems. This thesis divides roughly into two halves corresponding to these respective aims. In the first half I argue against the Standard Approach. Amongst other things, I suggest that the theory suffers from a tendency to take the notion of action for granted. The result is an oversimplified metaphysics that is ill-prepared to account for the fact that the activities characteristic of animal life are instrumentally structured processes. In the constructive half of the thesis I develop an Anscombean alternative that takes the structure of action as its starting point. On this view, expressions of animal agency are understood as a distinctive kind of material process. After explaining Anscombe's account of intentional action, I adapt and develop these ideas into a theory of animal agency.

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