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Rahm, Olivia. "Variations in Sex Differentiation : The Neurobiology of Gender Dysphoria." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17657.
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The aim of this review paper was to investigate variations in sex differentiation, andalso, examine what neurobiological underpinnings there are to gender identity andgender dysphoria. In addition, the most extreme form of gender dysphoria,transsexuality, will be described from a neurobiological perspective but also discussedin terms of the classification from DSM-5. One theory considered on how genderidentity originates is the fact that the sexual differentiation of the brain and thedifferentiation of sexual organs develop during different time periods. Alterationswere displayed in a demonstration of male-to-female (MTF) and female-to-male(FTM) transsexuals that showed reversed results in cell number in a part of thehypothalamus, acronymized INAH-3 and reversal volume results in another region,acronymized BSTc. Likewise, differences in grey matter in the right putamendepended upon their natal gender. It can be concluded that there is biologicalevidence for sex differentiation and indications that lead science into consideringbiological components for gender dysphoria. This conclusion suggests for futureresearch questions focused more on the possible genetic factors of gender identity,also, consider larger sample sizes and more replications. There is still incompleteknowledge of what exactly constitutes an individual’s gender identity.
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Acar, Adrienne Ann. "Clinical relevance of sex and age relate variations in corpus callosum morphology." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65830.
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Anatomical research of the morphology of the corpus callosum (CC) has provided a baseline for normal development of the CC. Although a large extent of variation amongst individuals has been reported, there are certain asymmetries that are consistently found in the size and shape of the CC on a midsagittal view of the brain. As the CC is the major commissural tract in the brain, it is acceptable to assume that structural variation in the CC may give clues towards the diagnosis of specific diseases. Studies relating alterations in the size and shape of the CC to the diagnosis of disorders have been done in individuals with schizophrenia, bipolar disorder (and depression. Thus, knowledge of CC anatomy in association with sex and age related changes can be helpful in providing a baseline for the diagnosis and progression of a specific disease. Morphological changes with regard to sex and age have been the topic of an extensive amount of research. However, there still remains considerable controversy as some studies report significant differences and others report none. The aim of this study was to provide a detailed description of the anatomy and variations of the corpus callosum morphology in a South African population. A primary data set was compiled using a cadaveric population, and these results were compared to a secondary data set, using a healthy living population. Lastly, the results from both data sets were then compared with a third data set, comprising of a mental disorder population, and results gained from previous studies in order to determine possible diagnoses of certain mental disorders based on CC morphology. In this study, there was no sexual dimorphism observed in the thickness of the genu, splenium and trunk in all three samples. In the cadaver sample there was no difference in the length of the CC. In the mental disorder sample there was no sexual dimorphism in the length of the CC and cerebrum. However, in the cadaver sample there was a significant difference in the length of the cerebrum between the sexes. In the healthy MRI scan there was a statistically significant difference observed in the length of the CC and the length of the cerebrum. It was found that there was no statistically significant difference in the thickness of the genu, trunk, and length of the CC and length of the cerebrum with age in all three samples measured. There was a statistically significant difference observed in the thickness of the splenium in the healthy MRI scan sample in individuals over the age of 60 years of age. This difference was not observed in the cadaver or mental disorder sample. There were no statistically significant differences in the various CC parameters measured in the various mental disorders measured. With the exception of two parameters, no differences in measurements were observed between the cadaver and healthy MRI sample. The two exceptions were the thickness of the trunk and the length of the cerebrum. Therefore, with the exception of the above mentioned cases, measurements between cadavers and living samples can be used interchangeably. Thus, the concerns about shrinkage in cadaver studies are negligible. However, when comparing the cadaver and healthy MRI scan sample with the mental disorder CT scan sample there was a statistically significant difference observed in every CC parameter measured. Thus, there is a rather noticeable difference in the anatomical structure of the CC in individuals suffering from mental disorders. Data on normal CC morphology is under represented in the South African population. Observations of variations from normal CC morphology can be used as an indicator for the possibility of a mental disorder.<br>Dissertation (MSc)--University of Pretoria, 2017.<br>Anatomy<br>MSc<br>Unrestricted
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Fournet, Damien. "Skin temperature variations in the cold." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/13551.
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Skin temperature plays an important role in human thermoregulation together with core temperature. Skin temperature varies to a large extent across the body and this is especially pronounced in cold environments. The variations of skin temperature are also involved in the generation of regional thermal perceptions that can lead to behavioural adjustments. Whilst the temporal and inter-individual variations of skin temperature have been well studied using contact sensors, the knowledge of spatial variations has received less attention in the literature. Infrared thermography is a specific imaging technique particularly valuable for the exploration of the topography or pattern of skin temperature across the body. Most research using this technique has only been case studies or experiments focused in one specific body region. However, extensive regional skin temperature data over the whole-body can be proven useful for different types of applications including the sport clothing industry in combination with other body-mapping data. The primary aim of this thesis was to develop an original and standardised method using infrared thermography enabling whole-body skin temperature data to be compared for the assessment of spatial, temporal and inter-individual variations. A specific methodology for infrared data collection and data processing was successfully developed in order to combine data from a variety of participants varying in anthropometrical characteristics. The main outcomes were the production of several skin temperature body maps, either absolute maps to show the magnitude of the temporal or inter-individual effects, and normalised maps (relative to mean skin temperature) allowing for topographical comparisons between protocol stages, populations or interventions. The second aim of the thesis was to extend the understanding of the skin temperature patterns and how these could relate with thermal perceptions. The body-mapping method gave the opportunity to investigate a large amount of conditions, where various internal or external determinants of skin temperature were be involved. This was mainly done in cool to cold environments (5°C to 20°C) where skin temperature is not uniform but is associated with local and overall comfort. Studies were firstly performed in semi-nude conditions (Chapter 3, 4, 5) and then in clothed conditions (Chapter 6 and 7). The semi-nude studies were designed to explore the potential sexdifferences in regional skin temperature responses whilst running (Chapter 3) with a special interest in the role of skinfold thickness, this was further extended with a group of males at rest having a large variety of fat content and thickness (Chapter 4). The influence of exercise type and air temperature on skin temperature patterns was studied with a rowing exercise (Chapter 5). Studies were then performed in clothed conditions (Chapter 5, 6). The influence of real-life conditions on skin temperature patterns and associated perceptual responses was observed during a hiking scenario (Chapter 6). Following these descriptive studies, manipulation of skin temperature patterns was performed using clothing in order to determine the presence of any relevant effect on thermal comfort (Chapter 7). Our results demonstrated that the skin temperature pattern over the whole-body is relatively universal with several features being consistently found regardless of the conditions or the populations. The upper body is usually warmer than the lower body and the body creases (orbital, elbow regions etc.) are also warmer than surrounding regions. A Y-shape of colder temperatures has been highlighted over the anterior torso as well as a T- or Y-shape of warmer temperature over the posterior torso. There are yet some specificities that can be displayed due to active muscles during exercise such as the warmer skin overlying the trapezius and biceps muscles in rowing (Chapter 5), the influence of the backpack construction with up to 3°C warmer skin temperature in the lower back (Chapter 6) or the importance of additional clothing insulation minimizing the anterior Y-shape of colder skin temperatures (Chapter 7). Beyond the thermal patterns, absolute skin temperature differences have been observed between sexes with females displaying 2°C colder skin during semi-nude running (Chapter 3) and 1°C colder skin during clothed walking (Chapter 6)compared to males. The skin temperature difference can also be as large as 6°C colder skin for an obese male compared to a very lean male (40% vs 7% body fat). Despite these differences, there were almost no significant differences in overall and regional thermal sensations and comfort between sexes or between males with varying body fat. Our results focused on body fat revealed that overall fat content and sum of skinfolds was inversely associated with the mean skin temperature response during various protocols (Chapter 4, 6, 7). Local skinfold thickness explained the inter-individual variability of local skin temperature for resting (Chapter 4) and exercising males (Chapter 7) in most body regions. In terms of intra-individual variations, the distribution of skinfold thickness across the anterior torso explained the distribution of skin temperature in this segment solely in conditions with strong regional contrasts (Chapter 3, 4 and 7). When the whole-body skin temperature pattern is considered, our body-mapping approach failed to show relationships between skin temperature distribution across the body and regional skinfold thickness distribution neither at rest nor during exercise. The relative contribution of other internal determinants such as local heat production,local blood flow distribution and local anthropometry should be further investigated to fully elucidate the spatial skin temperature variations depending on the climate, clothing and the body thermal state. Lastly, there was a trend towards improved thermal comfort during rest and exercise in the cold through a manipulation of skin temperature patterns targeting the naturally cold body regions with high insulation, therefore obtaining a more homogeneous skin temperature distribution across the body (Chapter 7). The present work will benefit the sport goods industry. The descriptive results of skin temperature variations will be useful in order to validate multi-segmental model of human thermoregulation. Further work can include pattern predictions for exercise types and conditions not covered by the present thesis. The skin temperature maps will mainly feed the general body-mapping approach for clothing design taking into account several other body mapping data such as sweat mapping and the combination of cold, warm and wetness sensitivity mappings. Lastly, the present results have highlighted the interest for targeted solutions and also the need for more evolutive systems in the field of cold weather apparel.
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Cornish, Kim M. "Variations in spatial cognition in adults and children : influence of handedness, familial sinistrality and sex." Thesis, Royal Holloway, University of London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242847.
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Roberts, Jonathan E. "Sex Differences on a Mental Rotation Task: Variations in Hemispheric Activation Between Children and College Students." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/31573.
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The area of cognitive research that has produced the most consistent sex differences is the area of spatial ability. Particularly, males usually perform better on mental rotation tasks than do females. One argument for these differences is that experience with spatial activity drives these differences, such that traditionally more masculine activities require more practice of spatial abilities. Another argument is biological in nature, such that there is either 1) a critical period of development that leads to differential lateralization of the brain, or 2) differential activation of the brain by circulating hormones. Performance on mental rotation tasks has been associated with right parietal activation levels, both during task performance and prior to performance during baseline recordings. The present study examined the relations among sex, age, EEG hemispheric activation (at the 10.5-13.5Hz. frequency band), and 2-dimensional mental rotation task ability. Nineteen eight-year-olds (10 boys) and 20 college students (10 men), had EEG recorded at baseline and while performing a mental rotation task. Men performed better on the mental rotation task than women, while there were no differences between boys and girls. After covarying for baseline EEG high alpha power values, EEG results during the mental rotation task indicated an interaction, with men exhibiting more activation (lower EEG power values at 10.5-13.5Hz) than women in the parietal and posterior temporal regions, while boys' and girls' power values 10.5-13.5Hz did not differ in the parietal or posterior temporal regions. Furthermore, during the baseline condition, men generally exhibited more activation (lower EEG power values at 10.5-13.5Hz) throughout all regions of the scalp. Results support the hypothesis that hormones, or hormonal influence, may result in a biological change which affects both brain activation and performance on mental rotation tasks.<br>Master of Science
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Wyatt-Hughes, Brandi. "The Heat Is On: Variations among Male and Female Chefs." TopSCHOLAR®, 2009. http://digitalcommons.wku.edu/theses/67.
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Bertault, Guillaume. "Variations adaptatives de la sex-ratio : vers une généralisation des modèles de manipulation en réponse à des facteurs environnementaux." Montpellier 2, 2002. http://www.theses.fr/2002MON20167.
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Odhiambo, Joseph A., Hywel C. Williams, Tadd O. Clayton, et al. "Global variations in prevalence of eczema symptoms in children from ISAAC Phase Three." Mosby Inc, 2009. http://hdl.handle.net/10757/625751.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.<br>Background: In 1999, The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One reported the prevalence of eczema symptoms in 715,033 children from 154 centers in 56 countries by using standardized epidemiologic tools. Objective: To update the world map of eczema prevalence after 5 to 10 years (ISAAC Phase Three) and include additional data from over 100 new centers. Methods: Cross-sectional surveys using the ISAAC questionnaire on eczema symptoms were completed by adolescents 13 to 14 years old and by parents of children 6 to 7 years old. Current eczema was defined as an itchy flexural rash in the past 12 months and was considered severe eczema if associated with 1 or more nights per week of sleep disturbance. Results: For the age group 6 to 7 years, data on 385,853 participants from 143 centers in 60 countries showed that the prevalence of current eczema ranged from 0.9% in India to 22.5% in Ecuador, with new data showing high values in Asia and Latin America. For the age group 13 to 14 years, data on 663,256 participants from 230 centers in 96 countries showed prevalence values ranging from 0.2% in China to 24.6% in Columbia with the highest values in Africa and Latin America. Current eczema was lower for boys than girls (odds ratio, 0.94 and 0.72 at ages 6 to 7 years and 13 to 14 years, respectively). Conclusion:ISAAC Phase Three provides comprehensive global data on the prevalence of eczema symptoms that is essential for public health planning. New data reveal that eczema is a disease of developing as well as developed countries.<br>Revisión por pares
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Kourtopoulos, Angeliki. "Perceived Educational Control (PEC) associated with Age, Parental Educational Attainment (PEA), School Type and Sex : A cross-sectional study including predictions and variations." Thesis, Högskolan i Gävle, Avdelningen för socialt arbete och psykologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-23666.
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The current study mapped trajectories of perceived educational control (PEC) through its association with age, parental educational attainment (PEA), school type (public or private) and sex. The study surveyed 280 Australian formal students, in a cross-sectional design, between the ages of 17 and 25. Results displayed increased age predicting higher levels of PEC. Having one educated parent predicted greater PEC across age than did having no educated parents. Interestingly, having two educated parents did not significantly elevate PEC. Awaited, was the insignificance of sex in the predictions of PEC, meanwhile school type, yet also an insignificant predictor has opened up for further discussion. No differences were found in PEC levels between school types or genders. Future research should include cultural background of the participant and school attended. Another useful perspective would be measured PEC in relation to likelihood of studying; for those finishing secondary school, or currently not studying.<br>Den aktuella studien mäter upplevd utbildningskontroll genom sin koppling till ålder, föräldrarnas utbildningsnivå, skolform (offentlig eller privat) och kön. I studien undersöktes 280 australienska studerande, i en tvärsnittsdesign, mellan åldrarna 17 och 25. Resultaten visar på att högre ålder förutsäger ökningar i upplevd utbildningskontroll. Att ha en utbildad förälder förutspår högre upplevd utbildningskontroll (över ålder) än att inte ha någon utbildad förälder. Dock visar det sig att ha två utbildade föräldrar inte signifikant höjer upplevd utbildningskontroll. Som väntat, förutsåg inte kön upplevd utbildningskontroll, likaså förutsåg inte skolform nivåer av upplevd utbildningskontroll, men denna prediktor har öppnat upp för vidare diskussion. Inga skillnader påträffades i upplevd utbildningskontroll nivåer mellan skoltyperna eller könen. Framtida forskning bör omfatta kulturell bakgrund av deltagaren samt skolan som respondenten gått i. Ett annat användbart perspektiv mäter upplevd utbildningskontroll i förhållande till sannolikheten att studera i framtiden; för dem som för närvarande inte studerar, eller avslutar gymnasiet.
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Howard, Christina Marie. "Seasonal and Sex Differences in the Effects of Melatonin on Brain Arginine Vasotocin in Green Treefrogs (Hyla cinerea): Relationship to Melatonin Receptor 1a." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1871.
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Critical life history events such as breeding, migration and hibernation must take place in the correct environmental context to minimize deleterious consequences on survival and reproductive fitness. Neuroendocrine mechanisms synchronizing internal physiological states with extrinsic environmental cues are vital to timing life history events appropriately. Secretion of the pineal hormone melatonin is sensitive to light and temperature cues, which provides a physiological indicator of time of day and time of year for organisms. Melatonin influences seasonal reproduction in a variety of vertebrates, likely by altering the synthesis and/or release of reproductive neuropeptides in the brain. The neuropeptides arginine vasotocin and its mammalian homologue, arginine vasopressin, are well-known modulators of reproductive and sociosexual behavior across vertebrate taxa, and are likely targets of melatonin in the context of seasonal reproduction. There is extensive evidence that vasotocin/vasopressin innervation in the brain is subject to seasonal variation, and that this variation is frequently sexually dimorphic. However, evidence that melatonin directly modulates this important neuropeptide system is lacking. Melatonin receptor 1a (MT1 in mammals) may be responsible for mediating melatonin's influence on brain vasotocin, as it is known to regulate seasonal reproduction in a variety of vertebrates. In the present study, I asked whether melatonin influences brain vasotocin in male green treefrogs (Hyla cinerea), and compared the distribution of melatonin receptor 1a in the brain of green treefrogs between sexes and seasons. Adult male and female green treefrogs were collected from field sites in Louisiana during the summer breeding season. Summer animals were acclimated to lab conditions for 3 weeks, then euthanized and their brains collected. Winter animals were maintained in the lab for four months under incrementally changing photo-, thermo-, and hygroperiod regimes that mimicked the transition to winter in their natural habitat, followed by euthanasia and brain collection. A subset of winter males (Experiment 1) were implanted with melatonin-filled or blank silastic capsules for a period of one month prior to euthanasia and brain collection. Brains of these males were processed for vasotocin immunohistochemistry. I quantified AVT-ir cell number in Experiment 1 males in the nucleus accumbens (NAcc), amygdala and caudal striatum (AMG), preoptic area (POA), suprachaismatic nucleus (SCN), and ventral hypothalamus (VH). Melatonin did not influence brain vasotocin-ir cell number in any brain region. Brains from untreated summer and winter males and females were collected and processed for MT1 immunohistochemistry. MT1-ir cells were quantified in the NAcc, striatum (STR), AMG, POA, SCN, and VH. In all regions quantified, reproductively active males had significantly more MT1-ir cells than nonreproductive males. Within the summer breeding season, males had significantly more MT1-ir cells in the NAcc than did reproductively active females. In all other regions there was no significant difference in MT1-ir cell number between reproductively active males and females. Collectively, these data suggest that melatonin modulates vasotocin via MT1. These findings assist in elucidating the neuroendocrine mechanisms by which vertebrates integrate seasonal cues with physiology to correctly time critical life history events.
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De, Cauwer Isabelle. "Importance relative des flux de gènes et de la valeur sélective individuelle dans les variations de sex ratio chez une espèce gynodioïque, Beta vulgaris ssp. maritima." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10048/document.
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Chez les plantes à fleurs, où une immense variété de stratégies de reproduction est rencontrée, la dispersion des gènes s’opère classiquement via des flux de pollen pour la voie mâle, et via des flux de graines pour la voie femelle. La gynodioécie correspond à un système de reproduction original, caractérisé par la coexistence de plantes femelles et de plantes hermaphrodites au sein de populations naturelles. Ce système de reproduction suscite depuis longtemps un intérêt particulier, du fait d’un paradoxe évolutif apparent : les individus femelles, ayant perdu une voie de transmission de leur information génétique, devraient être désavantagés par rapport aux hermaphrodites, dotés des deux voies de transmission des gènes. L’objet de ce travail thèse était d’expliquer le maintien des femelles et les importantes variations spatiales de sex ratio fréquemment observées dans les populations naturelles de betterave maritime (Beta vulgaris ssp. maritima), chez laquelle le déterminisme du sexe implique des interactions entre des gènes cytoplasmiques induisant la stérilité mâle (CMS) et des allèles nucléaires de restauration de la fonction mâle. En mêlant des approches de biologie et de génétique des populations, trois thématiques ont ainsi été abordées. (i) La valeur sélective des différents types sexuels a été mesurée, en faisant appel à des mesures phénotypiques en conditions contrôlées et à des analyses de paternité en populations naturelles. Ceci a permis de révéler un avantage femelle extrêmement restreint ainsi que des variations importantes du succès reproducteur mâle chez les hermaphrodites, liées notamment au génotype des individus et à l’existence d’un coût de la restauration. (ii) La caractérisation moléculaire de la diversité génétique au sein de plusieurs populations naturelles et entre plusieurs cohortes successives nous a permis de mettre en lumière l’importance relative des effets de la migration, des évènements de fondation et de la dérive génétique sur la structure spatiale des phénotypes sexuels. Les variations observées de sex ratio à très fine échelle semblent ainsi expliquées par des effets de fondation multiples couplés à des flux de pollen et de graines restreints dans l’espace. (iii) Finalement, nous mettons en évidence l’effet important que cette forte structure spatiale des sexes peut avoir, à la fois sur les individus hermaphrodites et sur les individus femelles. L’ensemble de nos résultats montre qu’une structure spatiale à fine échelle, générée par des évènements de fondation et des flux de gènes limités, peut affecter de façon importante la dynamique de la gynodioécie dans la nature<br>In flowering plants, which exhibit a spectacular diversity of reproductive strategies, gene dispersal generally occurs through two distinct pathways: pollen for the male function, and seed for the female function. Among sexually polymorphic flowering plants, gynodioecy refers to a particular breeding system in which females and hermaphrodites co-occur in natural populations. Since females reproduce only through seeds, they apparently transmit their genes only half as frequently as hermaphrodites, which gain fitness through both seed and pollen production. This apparent evolutionary paradox has attracted the attention of evolutionary biologists as far as the mid-nineteenth century. The aim of this PhD thesis was to understand the successful maintenance of female individuals and the important spatial variations in sex ratio that are often observed in natural populations of gynodioecious Beta vulgaris ssp. maritima, in which sex is determined by interactions between cytoplasmic male sterility (CMS) genes and nuclear restorers of male fertility. Using population biology and population genetics approaches, three distinct themes were considered. (i) First, male and female fitness of the different sexual types were compared, using both measures in controlled conditions and paternity analyses in the wild. While our results only suggest a very restricted female advantage, we detected strong male fitness differences among hermaphrodites that were partially explained by the genotype of individuals and by the occurrence of a cost of restoration. (ii) The study of the distribution of genetic diversity in several natural populations and in several consecutive cohorts allowed us to quantify the relative impact of migration, founder events and genetic drift on the spatial distribution of sexes. Overall, random founder effects with spatially restricted pollen and seed flow appeared to be the primary determinants of sex ratio variations. (iii) Finally, we explore how such sex ratio variation can affect the reproductive output of hermaphrodites and females. Altogether, we show that fine-scale spatial structure, resulting from the joint action of founder events and limited gene flow, can notably modify the dynamics of gynodioecy in natural populations
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Paul-Carrière, Lisa. "Apprenance et Genre : Variations d'Apprenance et de Dépendance-Indépendance à l’égard du genre (DIG) dans des contextes d'écoles d'ingénieur-e-s : contribution à une théorie de l’apprenance." Thesis, Paris 10, 2016. http://www.theses.fr/2016PA100179.
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Notre thèse de doctorat présente trois études menées en 2011, qui croisent et distinguent le niveau d’apprenance, le sexe et le rapport aux normes du genre de 779 étudiant-e-s en école d’ingénieur-e-s, ceci afin d’évaluer les liens pouvant exister entre ces différentes variables ainsi que leurs effets en contexte d’apprentissage. Sous le postulat que les variations de l’apprenance ne sont pas aléatoires, et qu’existent en dehors des dispositions personnelles, des éléments externes liés aux contextes sociaux et qui ont des effets sur les attitudes des sujets vis-à-vis de l’apprentissage, nous avons décidé d’étendre notre questionnement de départ sur l’apprenance aux liens qu’il pourrait y avoir entre l’apprenance, le sexe d’état civil des sujets et leur rapport aux normes du genre dans des contextes scientifiques d’écoles d’ingénieur-e-s que sont l’Ecole Centrale Paris (ECP), « L’EPF, école d’ingénieurs » anciennement Ecole Polytechnique Féminine (EPF), et Sup’Galilée, qui présentent une spécificité de sexe et un prestige variables<br>Our doctoral thesis presents three studies conducted in 2011, which intersect and distinguish the level of learnance, sex and the gender norms of 779 students in engineering school, in order to assess the links that may exist between these variables and their impact on learning environment. Under the assumption that changes in learnance are not random, and that exist outside the personal dispositions, external elements related to social contexts and that affect the attitude of subjects of learning, we decided to extend our initial questioning of learnance to links between learnance, sex and their relation to gender norms in engineer schools that are Ecole Centrale Paris (ECP), "the EPF engineering school" Ecole Polytechnique Feminine formerly (EPF) and Sup'Galilée which have a specific gender variables and prestige
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Lucas, Ashley Rae. "Neurobiology of Seasonal Life-history Transitions." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2511.
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Many animals exhibit seasonal changes in life-history stages, and these seasonal transitions are often accompanied by dramatic switches in behavior. While the neuroendocrine mechanisms that regulate such behavioral transitions are poorly understood, arginine vasotocin (AVT) and neuropeptide Y (NPY) are excellent candidates because they regulate reproductive and feeding behavior, respectively. In this study, I asked if seasonal changes in AVT and/or NPY are concomitant with spring migration away from the breeding grounds, as male and female red-sided garter snakes (Thamnophis sirtalis parietalis) are transitioning from reproductive to non-reproductive behavior during this time. To address this question, I collected male and female snakes in different migratory stages during the spring and fall. Brains were processed for AVT and NPY immunohistochemistry and the total number of immunoreactive (-ir) cells quantified for each individual. As predicted, males had significantly more AVT-ir cells in the preoptic area and bed nucleus of the stria terminalis, brain regions important for courtship behavior, during the spring mating season compared to the fall. Females had significantly more AVT-ir cells in the preoptic area during the spring compared to the fall and, surprisingly, did not exhibit seasonal changes in NPY. In contrast, males had significantly more NPY-ir cells in the cortex, a region important for spatial memory, and in the posterior hypothalamus during the fall compared to the spring, which likely reflects increased feeding behavior during the summer foraging period. Neither AVT- nor NPY-ir cell number varied significantly with migratory status, indicating that seasonal changes in these neuropeptides are not directly related to migration. I then asked if the observed seasonal changes in AVT and NPY in males and females are related to the transition from reproductive to non-reproductive states. Compared to courting males, non-courting males had significantly more AVT-ir cells in the supraoptic nucleus and more NPY-ir cells in the cortex. AVT- and NPY-ir cells did not differ between unmated and mated females. Collectively, my results suggest that AVT and NPY play a role in regulating seasonal transitions in male reproductive behavior, rather than regulating migration per se. Further, these data indicate that both AVT and NPY are regulating reproductive behavior differently in males versus females. These data provide the framework for future studies examining the mechanisms regulating transitions between reproductive, migratory and foraging behaviors.
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Murtagh, Gareth James. "Sex and variation in lichen-forming fungi." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285566.
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Bradbury, Richard. "The use of molecular markers of sex to investigate avian sex ratio variation." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296784.
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Judson, Olivia P. "Parasites, sex and genetic variation in a model metapopulation." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296922.
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Vandeputte, Marc. "Genetic variation of growth and sex ratio in the European sea bass (Dicentrarchus labrax L.) as revealed by molecular pedigrees." Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00957623.
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Le bar (Dicentrarchus labrax) est une espèce majeure de l'aquaculture méditerranéenne, dont la production est passée de presque rien en 1985 à plus de 100 000 tonnes annuelles aujourd'hui. Dans un grand nombre de cas, des géniteurs sauvages sont encore utilisés pour produire des juvéniles chez cette espèce, et l'on constate une forte prédominance des mâles, aux performances zootechniques inférieures, dans les populations d'élevage. Le but du présent travail de recherche était tout d'abord de quantifier les variations génétiques de la croissance et du sex ratio entre familles de bar produites par fécondation artificielle et élevées en commun, en utilisant le génotypage de locus microsatellites pour reconstruire les pedigrees des animaux mesurés. Dans un second temps, nous avons également étudié la réponse en termes de croissance et de sex ratio à une sélection expérimentale sur la croissance en longueur. Nous avons tout d'abord pu montrer que la technique expérimentale choisie (fécondation artificielle, élevage en commun et reconstruction des pedigrees par génotypage) était efficace et susceptible d'être appliquée non seulement en expérimentation, mais aussi pour la mise en place de programmes de sélection chez le bar. La croissance chez le bar montre une héritabilité élevée pour le poids à taille commerciale de 400g environ (h²=0.38-0.44), mais plus modeste pour le taux de croissance de 35 à 400g (0.16-0.34), montrant l'importance de la croissance précoce, très héritable (h²=0.61) dans la construction de la performance à taille commerciale. Par ailleurs, la croissance du bar n'est pas significativement influencée par des effets maternels non génétiques ou de dominance. Nous avons estimé les interactions génotype-milieu pour la croissance entre des sites de grossissement très différents, et si ces interactions se sont révélées modestes pour le poids à taille commerciale (rA=0.70-0.99 entre sites), elles étaient beaucoup plus fortes pour le taux de croissance (rA=0.21-0.61 entre sites). Bien que nous ayons à dessein choisi des environnements très différents pour ce test, ceci souligne l'importance de conduire les programmes de sélection dans un environnement proche de l'environnement d'élevage. Nous avons montré que le sex-ratio des populations naturelles de bar ne différait pas de 50-50 en moyenne, mais que certaines classes d'âge pouvaient avoir un sex-ratio biaisé, vraisemblablement du fait d'effets environnementaux. En élevage, les sex-ratios sont variables entre familles et influencés à la fois par le père et par la mère. Aucun modèle purement génétique ne permet d'expliquer les distributions observées, qui peuvent être décrites soit par un modèle ayant au moins deux loci bialléliques et une variance micro-environnementale, soit par un modèle polygénique à seuil (h²=0.62 pour la tendance sexuelle sur l'échelle sous-jacente). Avec ce dernier modèle, on note une corrélation génétique positive (rA=0.50) entre tendance sexuelle et croissance. Ceci permet de prédire que la domestication devrait permettre un rééquilibrage du sex-ratio vers 50-50, la sélection croissance biaisant le sex-ratio vers plus de femelles. C'est ce que nous observons ensuite dans notre expérience de réponse à la sélection pour la croissance. Cette même expérience nous permet de confirmer le potentiel de l'espèce pour une amélioration génétique de la croissance, avec un gain de 23% en première génération. Le modèle polygénique (ou à tout le moins polyfactoriel) de déterminisme du sexe est a priori rare chez les Vertébrés. Après avoir développé son utilisation possible pour obtenir à terme des populations de bars d'élevage monosexes femelles, le modèle polygénique est replacé dans la théorie du déterminisme du sexe chez les Vertébrés ectothermes, où il semble pouvoir être considéré comme beaucoup plus répandu qu'on ne le considère classiquement. [...] Suite et fin du résumé dans la thèse.
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Mouka, Aurélie. "Analyse des variations du nombre de copies d'ADN dans une cohorte d'hommes infertiles et génération de modèles génétiques d’étude de la méiose à partir de cellules iPS de patients infertiles." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS300/document.
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L’infertilité représente un problème majeur de santé publique en concernant 10 à 15% des couples en âge de procréer. Un facteur masculin est responsable de l’infertilité du couple dans près de la moitié des cas. Pour environ 30% d'entre eux, l'étiologie reste inexpliquée. Le premier axe du travail a concerné l’étude moléculaire d’une cohorte de patients infertiles (azoospermie non-obstructive/cryptozoospermie ou désordre du développement sexuel ou DSD) pour lesquels les analyses du caryotype standard et/ou des microdélétions des régions AZF par PCR n’ont pas permis d’expliquer le phénotype. L'impact des variations de nombre de copies de l'ADN (CNV) détectées par l'hybridation génomique comparative sur puce à ADN est peu documenté. Un design personnalisé de puce à ADN de format 400K, pangénomique et enrichi sur un large panel de 445 gènes liés à l'infertilité et à un DSD a été développé. Cette puce a permis l’identification de 171 CNV d’intérêt. Ces résultats soulignent l’intérêt de ce design comme outil diagnostic dans le cadre du bilan de l’infertilité masculine. Le second axe du travail a été de modéliser l’infertilité masculine in vitro dans un contexte d’anomalie génétique. Des cellules souches pluripotentes induites humaines (hiPS) ont été générées à partir d’érythroblastes de deux patients infertiles porteurs d’un remaniement chromosomique complexe ou d’un caryotype 46,XX-SRY négatif avec mutation du gène de l’AMH. Dans un deuxième temps, la fonctionnalité des lignées de cellules hiPS générées a été testée par différenciation in vitro en cellules germinales primordiales (CGP). Elles expriment les marqueurs clés du stade CGP dont SOX17, le déterminant germinal le plus précoce des CGP. Les perspectives de ce travail seront de poursuivre la différenciation germinale vers des stades plus matures et ainsi de pouvoir étudier le processus méiotique dans un contexte d’anomalie génétique<br>Infertility represents a major public health problem and concerns 10 to 15% of couples in the general population. A male factor is responsible for the infertility of the couple in about half of all cases. In approximately 30% of them, the etiology remains unexplained.The first working axis concerned the molecular study of a cohort of infertile patients (nonobstructiveazoospermia/ cryptozoospermia and disorder of the sex development or DSD) for whom analyses of standard karyotype and/or microdeletions of AZF regions were not able to explain the phenotype. The impact of copy number variations of DNA (CNVs) detected by comparative genomic hybridization (CGH-array) is poorly documented. A custom design 400K micoarray, genome-wide and enriched on a wide panel of 445 genes linked with infertility and DSD has been achieved. This array allowed the identification of 171 CNVs of interest.These results underline the potential of this design for diagnosis of male infertility. The second objective of this work was the in vitro modelisation of male infertility in a context of genetic abnormality. For that purpose, human induced pluripotent stem cells (hiPSCs) were generated from erythroblasts by means of not integrative Sendaï virus, in two patients carrying genetic abnormalities (complex chromosomal rearrangement and 46,XX-SRY negative karyotype associated with AMH gene mutation). Secondly, functionality of hiPSCs generated was tested by germ cells in vitro differentiation. Primordial germ cell (PGC) stage was successfully obtained. Cells expressed key PGC markers such as SOX17. The perspectives of this work will be to continuethe germinal differentiation towards more mature stages and so to be able studying the meiotic process in a context of genetic abnormality
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Dayger, Forbes Catherine Anne. "Why Do Animals Do What They Do, When They Do It? Characterizing the Role of the Hypothalamus-Pituitary-Adrenal Axis in Seasonal Life-History Transitions." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3614.
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Resource availability follows seasonal cycles in environmental conditions. To align physiology and behavior with prevailing environmental conditions, seasonal animals integrate cues from the environment with their internal state. One of the systems animals use to integrate those cues is the hypothalamus-pituitary-adrenal (HPA) axis and its primary effector, glucocorticoid hormones. The HPA axis has wide-ranging effects on physiology and behavior and, in the context of a glucocorticoid stress response, is known to mediate tradeoffs between immediate survival and future fitness. The HPA axis also plays an important role in facilitating predictable life-history events. Variation in HPA axis activity has been reported in all vertebrates, often coordinating seasonal reproduction and possibly also transitions between life-history stages. My dissertation research used red-sided garter snakes (Thamnophis sirtalis parietalis) to examine the role of the HPA axis in regulating seasonal life-history transitions, especially in females.
In Chapter 2, I hypothesized that seasonal plasticity in stress responses is regulated, in part, by changes in the responsiveness of the adrenal glands to adrenocorticotropic hormone (ACTH). I found that glucocorticoid responses to ACTH challenge were smaller in males than in females during the spring, suggesting that reports of reduced stress responsiveness in males may reflect lower adrenal responsiveness to ACTH. The sex difference in mating season duration and consequently also in the timing of migration led me to hypothesize that sex differences in HPA axis activity could explain sex differences in the timing of migration. Furthermore, adrenal responsiveness to ACTH also varied seasonally in males, but not females, suggesting that female stress responses, which have not been studied, may not vary seasonally.
In Chapter 3, I investigated potential seasonal variation in female stress responses, which have not previously been examined. In males, baseline glucocorticoids decrease over the course of the mating season resulting in significantly lower baseline levels in males that have begun to migrate. I hypothesized that a change in HPA axis activity occurs during spring and fall migration. Peak stress-induced glucocorticoid concentration occurred at an earlier sampling time in females during the spring compared to the fall. Peak stress-induced glucocorticoid concentrations also occurred at a later sampling time in migrating females than in pre-migratory females during the spring, suggesting that negative feedback regulation of the HPA axis changes as soon as females begin to migrate during the spring.
Female red-sided garter snakes are biennial breeders that give birth approximately every other year implying that a female's recent reproductive history can influence whether or not she will reproduce in a given year. Body condition can be used as a proxy for recent reproductive history and can be related to baseline and stress-induced glucocorticoid concentrations. In Chapter 4, I hypothesized that hormonal and behavioral stress responses vary with body condition. Baseline glucocorticoids did not vary with body condition, but females in low body condition showed a significantly larger increase in plasma glucocorticoids in response to capture stress. Body condition, but not capture stress, influenced latency to copulate, suggesting that females are resistant to the behavioral effects of capture stress during the spring mating season. Only females in low body condition increased latency to copulate in response to injection of a physiological (15 µg) dose of exogenous CORT, while all females responded to a pharmacological (60 µg) dose, indicating that behavioral responses to exogenous glucocorticoids vary with female body condition. These data suggest that variation in body condition may be associated with differences in HPA axis sensitivity and/or glucocorticoid receptor (GR) density in the brain.
I directly tested if there is a relationship among body condition, reproductive history and HPA axis activity in Chapter 5. I found that glucocorticoid stress responses and mating behavior did not vary with body condition, nor was body condition related to brain GR or reproductive condition (parturient vs post-parturient females). Only unreceptive females showed a significant stress-induced increase in glucocorticoids, suggesting that reduced stress responsiveness is associated with receptivity. Parturient females mated faster (were more proceptive) than post-parturient females. These data suggest that HPA axis activity influences reproductive "decisions" by modulating receptivity, while proceptivity is related primarily to recent reproductive history.
Together, these chapters help characterize how HPA axis activity varies with season, sex, reproductive history and migration status. By systematically probing the HPA axis in a single, tractable system, I have gained insight into how changes in the HPA axis support and modulate transitions between life-history stages. These results highlight the HPA axis' important function in mediating the critical trade-offs all animals must navigate to be successful in a changing world.
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Pettenuzzo, Daniele <1977>. "Sea Surface Temperature variations and air-sea physics parametrizations in the Mediterranean Sea." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2867/1/Pettenuzzo_Daniele_tesi.pdf.
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Pettenuzzo, Daniele <1977>. "Sea Surface Temperature variations and air-sea physics parametrizations in the Mediterranean Sea." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2867/.
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Buquicchio, Luke J. "Variational Open Set Recognition." Digital WPI, 2020. https://digitalcommons.wpi.edu/etd-theses/1377.
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In traditional classification problems, all classes in the test set are assumed to also occur in the training set, also referred to as the closed-set assumption. However, in practice, new classes may occur in the test set, which reduces the performance of machine learning models trained under the closed-set assumption. Machine learning models should be able to accurately classify instances of classes known during training while concurrently recognizing instances of previously unseen classes (also called the open set assumption). This open set assumption is motivated by real world applications of classifiers wherein its improbable that sufficient data can be collected a priori on all possible classes to reliably train for them. For example, motivated by the DARPA WASH project at WPI, a disease classifier trained on data collected prior to the outbreak of COVID-19 might erroneously diagnose patients with the flu rather than the novel coronavirus. State-of-the-art open set methods based on the Extreme Value Theory (EVT) fail to adequately model class distributions with unequal variances. We propose the Variational Open-Set Recognition (VOSR) model that leverages all class-belongingness probabilities to reject unknown instances. To realize the VOSR model, we design a novel Multi-Modal Variational Autoencoder (MMVAE) that learns well-separated Gaussian Mixture distributions with equal variances in its latent representation. During training, VOSR maps instances of known classes to high-probability regions of class-specific components. By enforcing a large distance between these latent components during training, VOSR then assumes unknown data lies in the low-probability space between components and uses a multivariate form of Extreme Value Theory to reject unknown instances. Our VOSR framework outperforms state-of-the-art open set classification methods with a 15% F1 score increase on a variety of benchmark datasets.
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McCullough, Melissa Theresa Doyle. "Variation in intestinal uptake of microparticles with age, sex and species." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394533.
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Maywald, Dionne Lee. "Palatability variation between the sex phenotypes of bladder saltbush (Atriplex vesicaria)." Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm474.pdf.
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Bibliography: leaves 105-121. This study reports the first thorough investigation of palatability variation in Atriplex vesicaria Heward ex Benth. (bladder saltbush). Intensive small-plot dietary trials, supported by a paddock dietary experiment, cross-fence comparisons and cafeteria trials, showed that sheep preferentially grazed female saltbushes over male and bisexual ones. Sheep avoided male saltbushes due to a chemical deterrent, and used visual (male flower spike) and olfactory cues to detect male plants. The effect of this selective grazing was to reduce the size and reproductive output of female shrubs. Sheep also tended to return to shrubs they had grazed previously. In the semi-arid regions of South Australia, where bladder saltbush is grazed year-round, physical protection is recommended to maximise survival and reproductive output of heavily grazed shrubs.
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Åström, Gustav. "CO2-Variation over the Baltic Sea." Thesis, Uppsala University, Department of Earth Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8026.
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<p>The increasing levels of the greenhouse gas carbon dioxide (CO2) in the Earths atmosphere, caused by human release of CO2, has made it desirable to understand the factors determining the CO2-variation because of CO2’s warming effect on the Earths temperature which will change the premises of all life on earth.</p><p>The purpose of this investigation is to understand the effects of the largest factors of influence on the CO2-concentration - like sea, vegetation and anthropogenic outlets - in the Baltic Sea region, and possible surprises from the results. To be able to do this only from CO2-measurements some assumptions have to be done as starting point. Such are that, besides from the yearly trend of the CO2-concentration and the variation of oceanic influence, monthly variation only is caused by vegetation and that the yearly offset in CO2-levels only is affected by anthropogenic outlets. These factors are together called the local season and will be used for evaluation of the CO2-values for each site. This analysis is done for eight sites surrounding the Baltic Sea region and is compared with results from the site of Östergarnsholm, an island in the Baltic Sea east of Gotland.</p><p>The results show that stations with high vegetational influence has high amplitudes for the local season compared to sites more influenced by sea. This also makes the amplitude to be connected with latitude since sites with longer growing season is surrounded by higher density of vegetation. The minimum for the local season is also dependent on the growing season, since it occurs when the vegetational consumption is largest. Peaks in the local season can be seen in connection with the maximum decay of the natural vegetation in the early winter months, and with the planting and harvest season for agricultural land. Considering the effect from anthropogenic influence a clear connection in the offset of the local season can be seen, with higher offsets for sites of higher anthropogenic influence and vice versa. Anthropogenic influence also seems to give raised values in summer for the local season, indicating that the variation of the local season cannot be simply connected to only vegetational influence. For variability, higher values in the summer months are seen for the anthropogenic sites, while in winter the variability is more similar for all sites. This might be connected with a higher degree of local influence during summers, which for anthropogenic stations leads to high variability due to inhomogenous surroundings.</p><p>For Östergarnsholm we get higher amplitude for the local season than expected, this is partly due to unrepresentatively high amplitudes for the seasons used, but also probably to some degree of underestimation of the vegetational influence. Due to correction of the offset it was not possible to draw any conclusions from this factor, but rather give suggestions of what the correction should be. When analysing the local season for different source areas by WD-classification we see the surprising property that the sector that should be most influenced by land, due to higher values in summer, has a lower amplitude than the sector most influenced by sea. Since it was suggested that anthropogenic influence gives raised values in summer this was suggested as an explanation.</p>
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Tangen, Mathias. "Wettability Variations within the North Sea Oil Field Frøy." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18416.
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Wettability is one of the most important parameters governing the rate of oil recovery from a porous medium. This thesis is a study of the wettability variations within the Frøy field in the North Sea, and its effect on the oil recovery. Several reports regarding the wettability and relative permeability of the Frøy field are available, and the conclusions from these reports are presented. The overall conclusion is that Frøy is on the oil-wet side of the wettability scale, with measured Amott-Harvey wettability indices ranging from -0.00189 to -0.73. An attempt was made to find wettability trends, relating the wettability index to variables such as distance above the water-oil contact, geological facies, permeability, the core’s staining level and so on, based on the measured data. Unfortunately, no such trend was identified.Only nine wettability measurements were available from the Frøy field while writing this thesis. This thesis concludes that in order to get a good statistical data set that can be used for establishing wettability trends, several wettability tests should be performed on cores sampled from a variety of distances above the water-oil contact, with different permeabilities and color staining levels, representing different rock types. And it is important to make sure that the cores have their original (native) wettability during the tests.More than 50 simulation cases have been made and run during the work on this thesis, testing the effect of wettability variations on Frøy, using the Schlumberger reservoir simulation program Eclipse 100. Wettability variations are simulated by assigning different relative permeability curves to different saturation function regions in the reservoir. For this reason, five sets of relative permeability curves were made, that represents wettabilities ranging from slightly water-wet to oil-wet, and different combinations of these curves were used in the simulation cases. There are many uncertainties in the given data and there are different ways of initializing the simulation model which may affect the simulation results. These issues are discussed in a separate chapter of the thesis.The simulation results showed that when the reservoir rock went from water-wet to oil-wet, the oil production went down, the water production went up, the water breakthrough occurred earlier and the oil recovery factor went down. The different producing wells were not equally affected by changes in the wettability.Two important conclusions were drawn from the simulation results. Firstly, it is difficult to estimate the effect of wettability variations on the production profiles if not the aquifer support and the fault transmissibility factors are modeled correctly, since these parameters also affect the production. And secondly, it is the wettability of the bottom half of the 225 meter thick reservoir zone that affects the production profiles of the wells. The wettability of the top half of the reservoir zone hardly affects the production profiles at all.
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Robertson, Michelle L. "Explaining variation in the sex composition of coaches for women's intercollegiate athletic teams." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/summer2006/M%5FRobertson%5F072706.pdf.
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Saalfeld, Sarah Therese Ditchkoff Stephen S. "Seasonal variation in sex ratios and survival rates of white-tailed deer fawns." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/SAALFELD_SARAH_36.pdf.
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Brindley, Emma L. C. "Variation in Robin (Erithacus rubecula) song : effects of season, sex and habitat acoustics." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334517.
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Desjobert, Hélène. "La beta 2 microglobuline humaine : données récentes sur ses propriétés et ses variations physiopathologiques." Paris 5, 1988. http://www.theses.fr/1988PA05P284.
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Dordain, Gaëlle. "L'humour dans la littérature de science-fiction : identification et spécification de ses contours, ses attibuts, ses techniques et ses variations." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOL003/document.
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Cette thèse se compose de deux parties. La première propose une théorie de l’humour, elle commence par étudier la notion en explicitant ses structures énonciatives, logiques ou encore syntaxiques afin d’en dégager une vision claire, avant de proposer une première tentative de définition. Puis elle établit des distinctions nécessaires entre les diverses catégories du risible afin d’affiner la délimitation des contours de l’humour. Une fois la notion circonscrite, la théorie de l’humour propose une typologie originale des thèmes humoristiques et une étude des trois variations principales de l’humour, avant de s’arrêter sur sa finalité. La deuxième partie aborde, à la lumière de certains concepts développés dans la première partie, la question de l’humour dans la littérature de science-fiction. En raison du peu d’études préalables sur la question, elle privilégie une optique large et traite divers aspects du phénomène. Dans un premier temps, la réflexion s’arrête sur la genèse, les thèmes et le pacte de lecture de la science-fiction pour analyser leur impact sur l’humour. Puis elle analyse la part effective de l’humour au regard des autres genres du risible avant d’interroger son développement et son rayonnement dans la science-fiction. Le dernier développement de la thèse interroge et classifie l’interaction entre l’humour et la science-fiction de la moins significative à la plus typique. Il aboutit au constat de l’existence d’un humour science-fictionnel qui s’appuie sur la puissance créatrice du genre. Enfin l’étude constate une distinction entre l’existence d’humour dans la science-fiction et la science-fiction humoristique en fonction de la quantité d’humour présente dans les textes. Elle s’intéresse alors plus précisément à la science-fiction humoristique et en dégage les structures en analysant les éléments saillants des récits, avant de s’intéresser à l’impact de cette dynamique relationnelle sur la construction des personnages<br>This thesis is divided in two parts. The first part suggests a theory of humour, it starts studying that concept by explaining its enunciative, logical or syntactical structures in order to draw a clear vision of it, before offering a first attempt to define it. Then it establishes necessary distinctions between the various categories of the risible to refine the delineation of the contours of humour. Once the concept is marked out, the theory of humour suggests an original typology of humourous themes and a study of the three main variations of humour, before focusing on its purpose. The second part discusses, in the light of certain concepts developed in the first part, the question of humour in science fiction literature. Because of the few previous studies on the matter, it opts for a broad perspective and deals with various aspects of the phenomenon. At first, thought dwells on the origins, themes and reading pact of science fiction to analyze their impact on humour. Then it analyzes the actual share of humour compared to the other categories of risible before studying its development and its influence in science fiction. The last development of the thesis examines and classifies the interaction between humour and science fiction from the least significant to the most typical. It reaches the conclusion of the existence of a science-fictional humour that leans upon the creative power of the genre. Finally, the study finds a distinction between the existence of humour in science fiction and humourous science fiction depending on the amount of humour in the texts. It then focuses on the humourous science fiction and identifies its structures by analyzing the prominent elements of the stories, before looking at the impact of this relational dynamics on the construction of the characters
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Mobley, Kenyon Brice. "Geographic and temporal variation in the genetic mating systems of pipefish." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1972.
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Berndt, Adam. "Untitled variation set (The Egg and the Flower)." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12054.
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Thesis (M.M.)--Boston University<br>This untitled set of variations started as sketches for viola and piano in the summer of 2012. I started the academic year planning to finish the piece by the end of the semester. I was informed shortly after the start of the semester, by Sam Headrick, of my tentative placement on the Allea III Young Composers Concert on February 6th, 2013- my priorities changed. The initial sketches for the viola piece became the seeds for this one but this piece bears little semblance to what the viola piece would have been. This piece is a series of five variations, the last serving as a sort of coda to the previous four. The subtitle, The Egg and The Flower, refers to opposing types of material in the piece; flourishing material used to close variations and pitch-organized material.
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Svahn, Kristina. "Kreativitet, variation och pedagogiska floskler : Diskursiva mönster i samtal med sex gymnasielärare om estetiska lärprocesser." Thesis, Högskolan i Halmstad, Sektionen för lärarutbildning (LUT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-21557.
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Det här arbetet har undersökt hur sex gymnasielärare med olika ämnesprofil diskuterar ochsamtalar kring estetiska lärprocesser. Resultatet utgår från två fokusgruppsintervjuer på två olikagymnasieskolor i sydvästra Sverige. Syftet har varit att genom samtalen få en bild av hur lärarnakonstruerar och legitimerar estetiska lärprocesser i klassrummet samt att utifrån diskussionenidentifiera de diskursiva mönster som framträder i samtalen. Arbetet tar sitt avstamp isocialkonstruktionism och använder diskursanalys som vetenskaplig metod. I analysenframträder fyra diskurser kring vilka lärarna diskuterar de estetiska lärprocesserna. Av resultatetframgår att begreppet estetiska lärprocesser i sig är abstrakt och svåranvänt, kreativitet är iställetdet begrepp som lyfts fram och som anses eftersträvansvärt i all undervisning. Lärarna ser ocksåvariation som en viktig del av undervisningen i skolan, för att möta olika elevers och klassersbehov, men också för att variation är något bra i sig. Här blir den estetiska dimensionen ettpedagogiskt sätt bland flera som skapar variation och gör undervisningen roligare och merkreativ. Lärarna lyfter dock fram att den stoffträngsel som finns i kursplaner och kursmål gördet svårt att i praktiken arbeta så processorienterat och kreativt som man gärna skulle vilja ochatt det därmed finns en motsättning mellan pedagogiska idéer och den faktiska verkligheten. Ettfaktum som också skapar irritation och frustration hos vissa lärare som tycker att olikapedagogiska begrepp lanseras utan förankring i verkligheten.
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Muller, Samantha. "Shape analysis of the zygoma to assess ancestry and sex variation in modern South Africans." Diss., University of Pretoria, 2021. http://hdl.handle.net/2263/78395.
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Skeletal remains exposed to an outdoor context are prone to post-mortem damage and fragmentation, making skeletal analysis difficult for the anthropologist. Research on ancestry and sex from isolated fragments of the cranium is necessary to improve identification of fragmented remains. The zygoma has proven to be more durable post skeletonization than other cranial bones, making research relevant into variation within the zygoma. Whilst the shape of the zygoma has been studied in a South African population using morphological, metric and geometric morphometric techniques, these studies did not include Indian South Africans. The Indian South African population comprises 2.6% of the total population but make up a larger proportion of the population in certain areas. For example, Indian South Africans comprise 7.4% of the population in Kwa-Zulu Natal and 2.9% in Gauteng. More specifically, Indian South Africans make up to 60% of the population in the suburb of Chatsworth with a further 91% of the population in sub-area of Arena Park, and 80% of the population in the Laudium suburb of Gauteng. Therefore, Indian South Africans must be included in anthropological studies attempting ancestry classifications. The purpose of the study was to assess the shape variation and projection of the zygoma attributable to sexual dimorphism and ancestral variation among South Africans, including Indian South Africans, using a geometric morphometric approach.
A sample of 400 three-dimensionally (3D) reconstructed models from head CT scans of black, coloured, white, and Indian South Africans were used with an equal sex and ancestry distribution. Eleven landmarks previously described in the literature were used for the analysis. Each landmark was used to depict the most prominent points on the outline of the zygoma. Additionally, semi-landmarks were placed along the curves of the zygoma. The landmarks and semi-landmarks were tested for observer repeatability and reliability using dispersion analysis and revealed that all landmarks were repeatable. Procrustes ANOVA revealed significant differences among the population groups and between the sexes for all population groups, except between coloured South African males and females. A pairwise post-hoc test revealed that white and Indian South Africans had the most similarities except for males, where coloured and Indian South Africans had the most similarities for landmarks.
Three interlandmark distances were created to assess the zygoma’s projection. The ANOVA for the projection of the zygoma revealed significant differences for both sex and ancestry except for white South African males and females and males overall for the zygomaticomaxillary length. The zygomaticomaxillary length (ZML) is defined as the maximum distance between the landmarks zygoorbitale and zygomaxilare. No significant differences were noted for female South Africans for the Superior Zygomatic Length which, is a measure of the maximum length of the superior margin of the zygoma (between porion and zygoorbitale; PorZygool). Further analysis of the zygoma’s projection involved creating angles between the interlandmark distances. The ANOVA for the angles of projection revealed significant differences between sexes and populations, except for white and Indian South African males and females at Angle1 (Angle at the intersection of ZML and PorZygoml) and Angle3 (the angle at the intersection of PorZygool and PorZygoml) and black, coloured and Indian South African males and females at Angle2 (the angle at the intersection of ZML and PorZygool).
The large amount of overlap amongst ancestry groups demonstrated substantial group similarities; however, differences were noted at the zygomaxillary, zygomaticotemporal and frontomalar sutures. Overlap was also present between males and females, but on average, males were larger than females. Differences, such as a more inferior placement of the zygoorbitale landmark were noted at the inferior margin of the orbit specifically in females. Differences were also noted at the inferior margin of the orbit across all groups. Discriminant functions were created to assess the classifying ability of the shape of the zygoma. Results revealed low accuracies for ancestry classification for the shape and projection of the zygoma. However, higher accuracies were noted for sex classification for the shape and projection of the zygoma.
While results demonstrate shape variation of the zygoma, the classifying ability of the zygoma is precarious at best, and the use of the zygoma in a forensic context may not be an option. However, the differences observed can be taken into consideration during medical procedures such as zygomatic and infraorbital implants. Although landmark placements were reliable and repeatable, further analysis of the zygoma using a semi-automatic surface registration method along with different imaging techniques (MicroCT and CBCT scans) may assist in the data collection procedure and may potentially increase the accuracy of the results. Furthermore, the results of the current study highlight the need for the assessment of the effects of diet, climate, age, edentulism and symmetry on the shape of the zygoma.<br>Dissertation (MSc (Anatomy))--University of Pretoria, 2020.<br>National Research Foundation (NRF)<br>Anatomy<br>MSc (Anatomy)<br>Unrestricted
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Miser, Tracey M. "Variations in SES, home environment, and childcare on child language abilities." Connect to resource, 2010. http://hdl.handle.net/1811/45426.
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Kuhlmann, Julian [Verfasser]. "Simulated And Observed Sea Level And Ocean Mass Variations / Julian Kuhlmann." Berlin : Freie Universität Berlin, 2014. http://d-nb.info/1049437926/34.
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Fabrèges, Dimitri. "Phenotypic Variations In Animal Morphogenesis : Sea Urchin Twins And Cloned Rabbits." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS010/document.
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La variabilité est une propriété intrinsèque aux systèmes biologiques, essentielle pour l'évolution et l'embryogénèse. Souvent considérée comme du bruit, ce n'est que récemment que l'aléatoire des processus biologiques a commencé à être systématiquement étudié. Cette thèse pose les questions suivantes : qu'est-ce qu'un développement normal ? Quel est l'étendue et le rôle de la variabilité dans la robustesse et la résilience du développement embryonnaire ?Ces questions sont posées pour le lapin (Oryctolagus cuniculus) et l'oursin (Paracentrotus lividus et Sphaerechinus granularis).Nous nous sommes aussi intéressé à la quantification du déterminisme de la variabilité embryonnaire à l'aide d'oursins jumeaux et de lapins clonés.La mesure des comportements cellulaires est effectuée sur des lignages cellulaires obtenus à partir d'imagerie 3D+temps. Nous montrons que les oursins jumeaux peuvent se développer selon trois phénotypes différents, jamais observés chez le normal, avant de converger vers une blastula d'apparence normale. De plus, les comparaisons entre et au sein des pairs de jumeaux montrent que le phénotype et la survie ne dépend que de l'histoire individuelle des embryos.Nos mesures quantitatives des pairs de jumeaux amènent des questions ouvrant de nouveaux horizons de recherche : les jumeaux sont-ils robustes ou résilient ?Le développement pré-implantatoire des lapins a été étudié sur cinq embryons numériques (trois sauvages et deux clones), du stade 32-cellules à l'éclosion.Nous montrons que les divisions asymétriques internes et externes régulent la variation du nombre de cellules internes ainsi que la taille de la masse cellulaire.De plus, la variation du nombre de cellules internes est plus grande que pour les cellules externes, ce qui semble directement lié au taux de morts cellulaires.Notre hypothèse est que le potentiel de bon développement des clones est assuré par une grande plasticité épigénétique des cellules donneuses.Ce travail espère définir des méthodes et des concepts fondateurs pour une exploration quantitative et une modélisation multi-échelle de la morphogénèse animale<br>Variability is an intrinsic characteristic of biological systems, essential for evolution and embryogenesis.Considered as noise for centuries, it is only recently that the stochasticity of biological processes has began to be systematically explored.The present thesis addresses the following questions: What is a normal development?What is the extent and role of variability in developmental robustness and resilience?We tackle these issues in rabbit (Oryctolagus cuniculus) and sea urchin (Paracentrotus lividus and Sphaerechinus granularis).We also aimed to quantify determinism and stochasticity of developmental variability by means of sea urchin twins and cloned rabbits.Variations in cell behaviors were investigated through reconstruction of cell lineage from 3D+time imaging.We showed that sea urchin twins can follow three different developmental paths never observed in normal embryo, before converging to normal looking blastula.Moreover, comparisons between and within pairs of twins revealed that phenotype and survival depend on individual history alone.Our quantitative observation of twin pairs raises question opening a future line of research: are twins robust or resilient?Rabbit preimplantation development was explored with five digital specimens (three wild-types and two clones) from the 32-cell stage to hatching.We showed that inner and outer asymmetric divisions regulate the variation of inner cell number and may control inner cell mass size.In addition, the variation of inner cell number in clones is higher than outer cells which seems to be directly correlated to their cell death ratio.Our current hypothesis is that the potential to lead to viable clones requires plasticity of donor's epigenetic state.This work is expected to ground concepts and methods for a quantitative exploration and further multilevel modeling of morphogenetic processes
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Ruggieri, Gabriella <1978>. "Sea Level Variations from Decades to Millennia: A few Case Studies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4289/1/ruggieri_gabriella_tesi.pdf.
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The main goals of this Ph.D. study are to investigate the regional and global geophysical components related to present polar ice melting and to provide independent cross validation checks of GIA models using both geophysical data detected by satellite mission, and geological observations from far field sites, in order to determine a lower and upper bound of uncertainty of GIA effect. The subject of this Thesis is the sea level change from decades to millennia scale. Within ice2sea collaboration, we developed a Fortran numerical code to analyze the local short-term sea level change and vertical deformation resulting from the loss of ice mass. This method is used to investigate polar regions: Greenland and Antarctica.
We have used mass balance based on ICESat data for Greenland ice sheet and a plausible mass balance for Antarctic ice sheet.
We have determined the regional and global fingerprint of sea level variations, vertical deformations of the solid surface of the Earth and variations of shape of the geoid for each ice source mentioned above.
The coastal areas are affected by the long wavelength component of GIA process. Hence understanding the response of the Earth to loading is crucial in various contexts. Based on the hypothesis that Earth mantle materials obey to a linear rheology, and that the physical parameters of this rheology can be only characterized by their depth dependence, we investigate the Glacial Isostatic Effect upon the far field sites of Mediterranean area using an improved SELEN program. We presented new and revised observations for archaeological fish tanks located along the Tyrrhenian and Adriatic coast of Italy and new RSL for the SE Tunisia. Spatial and temporal variations of the Holocene sea levels studied in central Italy and Tunisia, provided important constraints on the melting history of the major ice sheets.
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Ruggieri, Gabriella <1978>. "Sea Level Variations from Decades to Millennia: A few Case Studies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4289/.
Full textAbstract:
The main goals of this Ph.D. study are to investigate the regional and global geophysical components related to present polar ice melting and to provide independent cross validation checks of GIA models using both geophysical data detected by satellite mission, and geological observations from far field sites, in order to determine a lower and upper bound of uncertainty of GIA effect. The subject of this Thesis is the sea level change from decades to millennia scale. Within ice2sea collaboration, we developed a Fortran numerical code to analyze the local short-term sea level change and vertical deformation resulting from the loss of ice mass. This method is used to investigate polar regions: Greenland and Antarctica.
We have used mass balance based on ICESat data for Greenland ice sheet and a plausible mass balance for Antarctic ice sheet.
We have determined the regional and global fingerprint of sea level variations, vertical deformations of the solid surface of the Earth and variations of shape of the geoid for each ice source mentioned above.
The coastal areas are affected by the long wavelength component of GIA process. Hence understanding the response of the Earth to loading is crucial in various contexts. Based on the hypothesis that Earth mantle materials obey to a linear rheology, and that the physical parameters of this rheology can be only characterized by their depth dependence, we investigate the Glacial Isostatic Effect upon the far field sites of Mediterranean area using an improved SELEN program. We presented new and revised observations for archaeological fish tanks located along the Tyrrhenian and Adriatic coast of Italy and new RSL for the SE Tunisia. Spatial and temporal variations of the Holocene sea levels studied in central Italy and Tunisia, provided important constraints on the melting history of the major ice sheets.
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Kutiech, Nisreen. "Determinants of variation in the response of the aphid parasitoid Aphidius ervi to aphid sex pheromones." Thesis, University of Plymouth, 2008. http://hdl.handle.net/10026.1/1129.
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Variation in parasitoid responses to semiochemicals may be influenced by genetics, phenotypic plasticity and the individual's physiological state. Previous experimental work has indicated a high degree of variability among parasitoid individuals in their response to aphid sex pheromones but no work has been done to investigate the factors behind such variation. Some aspects of this variation were investigated in the aphid parasitoid Aphidius ervi (Haliday) (Hymenoptera: Braconidae) in the laboratory. Conducting behavioural experiments, the searching behaviour of females was investigated in the presence and the absence of the aphid sex pheromone (4GS,7S,7a/?)-nepetalactone, observing the same individual female parasitoids during two consecutive foraging attempts on different plants. The first set of observational experiments demonstrated the role of the pheromone as an arrestant in the searching behaviour of A. ervi and its additive effect when it was presented with other foraging cues such as aphid-induced plant volatiles. The second set of behavioural experiments showed significant differences in A. ervi responses to the pheromone depending on their physiological state. Virgin, well-fed and high egg-load females were more active in the presence of the aphid sex pheromone than mated, hungry and low egg-load females although there were no significant differences in their activities in the first foraging attempt when the pheromone was absent. The effect of the pheromone on the searching behaviour of A. ervi within different tritrophic systems was investigated. The results showed variation in this response depending on which host aphid and/or the host plant they had been reared, showing that "conditioning" may have an influence on this response. Using two isofemale lines and an insectary-maintained laboratory population of A.ervi, the genetic basis of this response was investigated. The behavioural experiments showed no significant differences between the three different populations in their response to aphid sex pheromones. A supportive molecular study using DNA microsatellites v/as also conducted, which revealed low genetic variability among the three studied populations. The results are discussed in the context of using the response of A. ervi to aphid sex pheromones in a strategy to manipulate natural populations of the parasitoid for the biological control of aphids and the importance of studying the variation in this response to increase the effectiveness of such strategy.
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Karcanias, Alexandra. "Investigation of genomic DNA copy number variation on the human sex chromosomes associated with genetic pathologies." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612017.
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Henningsson, Susanne. "Influence of serotonin- and sex steroid-related genetic variation on mood, anxiety, personality, autism and transsexualism /." Göteborg : Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, 2008. http://hdl.handle.net/2077/18354.
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Tise, Meredith L. "Craniometric Ancestry Proportions among Groups Considered Hispanic: Genetic Biological Variation, Sex-Biased Asymmetry, and Forensic Applications." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5141.
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Today, groups considered Hispanic in the United States consist of populations whose complex genetic structures reflect intermixed diverse groups of people who came in contact during Spanish colonization in Latin America. After coming in contact and wiping out most of the Native Americans who occupied North and Latin America, the Spanish also introduced West African individuals for labor to begin developing crops to be shipped back to Europe, resulting in the Trans-Atlantic African slave trade. These migration events and differential gene flow among males and females that occurred throughout Latin America have led to populations that have been genetically transformed from what they were prior to Spanish arrival (Madrigal, 2006).
Genetic research commonly refers to individuals considered Hispanic as "tri-hybrids" of Native American, European, and African ancestry (Bertoni et al., 2003; Gonz[aacute]lez-Andrade et al., 2007). This research focuses on populations from present-day Mexico, Puerto Rico, and Cuba, all of whom experienced various population histories as these three ancestral groups came in contact. Published genetic research demonstrates that individuals from Mexico tend to have the highest mean proportion of Native American ancestry, while Puerto Rican individuals have the highest mean proportion of European ancestry, and Cuban individuals have the highest mean proportion of African ancestry (Bonilla et al., 2005; Lisker et al., 1990; Mendizabal et al., 2008; Tang et al., 2007; Via et al., 2011). The present research utilizes craniometric data from these three groups to determine whether the cranial morphology reflects similar population relationships and mean ancestry proportions as found in genetic research through Mahalanobis distance (D2), canonical discriminant function, and normal mixture cluster analyses. Sex-biased ancestry asymmetry was also tested by separating each group by sex and running the same analyses.
The results show that all three groups considered Hispanic (Mexico, Puerto Rico, and Cuba) are significantly different from each other; however, when proxy ancestral groups are included (Guatemalan Mayan, Indigenous Caribbean, Spanish, and West African), the Mexican and Guatemalan Mayan samples are the most similar, followed by the Mexican and Indigenous Caribbean samples and the Puerto Rican and Cuban samples. The results of the normal mixture analyses indicate that Mexico has the highest mean ancestry proportion of Native American (Guatemalan Mayan) (72.9%), while the Puerto Rican and Cuban samples both have a higher mean European ancestry proportion, with 81.34% and 73.6% respectively. While the Cuban sample is not reflective of the genetic research in regards to ancestry proportion results, with the highest proportion of African ancestry over European and Native American ancestry, it does have the highest proportion of African ancestry among the three groups (18.4%). When separated by sex, the results indicate that the Mexican and Puerto Rican samples may show some evidence in sex-biased ancestry proportions, with the male individuals having a larger proportion of European ancestry and the female individuals having a larger proportion of Native American or African ancestry. Cuba, on the other hand, does not follow this trend and instead displays a higher proportion of European ancestry in females and a higher proportion of Native American and African ancestry in the males.
Techniques in the field of forensic anthropology in the United States are constantly being reanalyzed and restructured based on the changing demographics of the population, especially with the arrival of individuals from Latin America (Ennis et al., 2011). Recent samples of American Black and White individuals were included in the Mahalanobis distance (D2) and canonical discriminant function analyses in place of the ancestral proxy groups to determine the craniometric relationship of the groups within the United States. The results show that the Mexico and Guatemala samples are the most similar (D2=2.624), followed by the Cuba and American Black samples (D2=3.296) and the Puerto Rico and American White samples (D2=4.317), which each cluster together in pairs. These results reflect the population histories that took place during colonialism, with the largest amount of slave trade occurring in Cuba over the other two countries. From an applied perspective, clarification is needed in the biological definition of Hispanic and the degree of heterogeneity in each social group, as well as the relationship among groups, in order to accurately develop techniques in forensic anthropology for human identification.
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Chaperon, Sylvie. "Du féminisme à la sexologie, variations sur le sexe et le genre." Habilitation à diriger des recherches, Université Panthéon-Sorbonne - Paris I, 2007. http://tel.archives-ouvertes.fr/tel-00403886.
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Ivanochko, Tara S. "Sub-orbital scale variations in the intensity of the Arabian Sea Monsoon." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/760.
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A high-resolution multi-proxy reconstruction of the Arabian Sea Summer Monsoon (ASSM) intensity over the past 90,000 years has been determined using two marine sediment cores: one from the Somali margin and one from the Indian margin. This reconstruction indicates that changes in monsoon- induced upwelling, primary productivity and denitrification have varied in synchrony with Dansgaard-Oeschger (D-O) cycles. Increased monsoon intensity correlates with warm climate events (interstadials) and decreased monsoon intensity, which coincides with stadials and Heinrich Events, is confirmed by elevated dust concentrations in the marine cores. A comparison of the Somali and Indian margin cores with previously reported studies from the Northern and Western Basin allows the identification of discrete sediment signals from the Indus River, the Arabian Peninsula and from local riverine runoff. Sedimentary deposition on the Indian margin during interglacials is dominated by local terrestrial runoff, whereas during glacial periods increased dust input from the Arabian Peninsula is evident. Both signals are related to changes in the intensity of the ASSM. Monsoon intensity has decreased during the Holocene as the Intertropical Convergence Zone (ITCZ) has moved to a more southerly position. The ASSM-ITCZ relationship (increased ASSM intensity and a northern ITCZ, decreased ASSM intensity and a southern ITCZ) has remained consistent over the last glacial cycle suggesting that global millennial scale climatic variability is in part driven by modulations in tropical hydrological cycle. This ASSM reconstruction provides evidence that rearrangements in the tropical convection system affected atmospheric dust concentrations as well as the concentration and location of atmospheric water vapour. In addition to modulating terrestrial and marine emissions of greenhouse gases, variation in the tropical hydrological cycle provides a mechanism of amplifying and perpetuating millennial-scale climatic changes.
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Thomas, A. R. "Glacial-interglacial variations in the geochemistry of North Atlantic deep-sea sediments." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382148.
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Withnell, Anthony James. "Relative sea-level variations revealed by tide-gauge records of long duration." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/58421.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990.<br>Includes bibliographical references (leaves 65-67).<br>by Anthony James Withnell.<br>M.S.
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Nwilo, Peter Chigozie. "Sea level variations and the impacts along the coastal areas of Nigeria." Thesis, University of Salford, 1995. http://usir.salford.ac.uk/43024/.
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A brief review of the Nigerian Coastal Areas including the geology, geomorphology, topography, climate, and vegetation has been given. Nigeria has a coastline of about 850km facing the Atlantic Ocean and the coastal areas support a population of about 20 million people and a myriad of economic activities. Global sea level is known to be rising gradually and in some areas due to subsidence either from natural tectonic actions or in combination with fluid withdrawal from under the ground, the rate is much higher than the global average. The latter situation is believed to be the case on the Nigerian Coast where oil and gas exploitation and water supplies are being withdrawn from under the ground at uncontrolled rates. Tidal data obtained from the Nigerian Coast have been used to study the various sea level variations on that Coast. Using 19 years of tidal data from Bonny, the sea level is observed to be rising at the rate of about 1mm per annum compared to the global average results between 1 -2mm per annum. Forty years of tidal data from Takoradi Port, Ghana also on the Atlantic Coast of West Africa have showed a rise of 3.9mm per annum. The contribution due to subsidence has not been determined because the tide gauge benchmark have not been connected to a stable control point and monitored regularly. Maximum surges of the order of 7m were observed. Other variations and characteristics of the sea level on the Nigerian Coast include seasonal, tidal ranges, frequency distribution of tidal data, and behaviour of the tidal data in absence of some major tidal constituents. The impacts of these variations on the Nigerian Coast have been studied. These include erosion, flooding and inundation, salinity intrusion, destruction of coastal settlements, deforestation and destruction of the marine ecosystem, increased effect of oil spillage on the Coastal environment, and destruction of infrastructural facilities and industries. Response measures have been discussed and the integrated management of the coastal areas of Nigeria is seen as a very important response in addressing the impacts, development, and management of the Nigerian Coastal environment. Continuous data collection, monitoring of the various processes on the Coast, further researches and regional cooperation on the issue of sea level variations are recommended as very important components.
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Farquhar, Michael Robert. "Interspecific interactions of the sea urchin Parechinus angulosus and the effect of variations in microhabitat availability." Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1005406.
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Intertidal populations of the sea urchin Parechinus angulosus were examined at seven sites along the south and east coasts of South Africa. At the five southerly sites, P. angulosus occurred in allopatry, while, at the two northerly sites, it occurred in sympatry with several species of Indopacific sea urchins. At the five southerly sites, there was a significant correlation of number of sea urchins per pool with the surface area of the overhang in that pool. This relationship broke down for P. angulosus at the two northerly sites, where there was a significant correlation between these two factors for Stomopneustes variolaris. The density of populations of P. angulosus at the two northerly sites, although not significantly different from all five southerly sites, were considerably lower. There was a significant difference between the mean size of populations at the seven sites. Although no direct evidence is available, a competitive interaction between these two species is proposed to explain the observed patterns of microhabitat utilization and densities. Two series of manipulative experiments were conducted at Kowie Point, where P. angulosus occurs in sympatry, The first, involved urchin removals from three experimental sites. The percentage cover of four functional algal groups was monitored in three experimental and three unaltered control sites over a three month period in spring (Sept. - Dec.) 1993. Two 100 point 0,25m² random point quadrats were thrown at each of the six sites at approximately monthly intervals over the experimental period. Since initial cover of algae varied at the six sites, ANOVA's of the change in percentage cover of four functional algal groups were used to determine treatment effects. No treatment effects were identified for any of the four functional algal groups. There was a strong negative correlation between the percentage cover of foliose algae and encrusting coralline algae, suggesting the possibility of a competitive relationship between them. The second, involved the experimental manipulation of microhabitat availability. The blocking of overhangs, by means of cement filled bags, resulted in an approximate 50% decrease in the total number of urchins in the two experimental pools, and the two control pools without overhangs. However, in the control pool with overhangs there was a slight increase in the number of urchins over the same period. Clearly, the presence of suitable shelters, is a prerequisite for the maintenance of dense intertidal population of P. angulosus. It is proposed that, due to the exposed nature of the South African coast, intertidal populations of P.angulosus are restricted to inhabiting suitable shelters from which they emerge to feed on passing drift algae. The implications of these findings are discussed in terms of current ecological literature.