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

The ecology of ageing in albatrosses

Froy, Hannah January 2014 (has links)
Age-related variation in demographic rates has significant consequences for population and evolutionary dynamics, and understanding the processes driving such variation is therefore an important aspect of evolutionary ecology. Reproductive performance may vary over the lifetime of an individual, and this may be the result of both variations in reproductive effort and changes in individual competency. For example, increasing experience is likely to have beneficial effects on reproduction during early life, and senescence, or declines in physiological function, may have negative impacts on the performance of older individuals. The rate at which these changes occur can vary dramatically between species, and even between individuals of the same species. However, understanding the causes and consequences of this variation in the rate of ageing is not always straightforward. As well as the individual-level processes described, the phenotypic composition of successive age classes will contribute to age-related variation observed at the population level. Abrupt changes in performance, such as the poor performance of first time breeders, may be obscured if individuals vary in their age at first reproduction. Population-level patterns may also be influenced by selection; for example, the selective disappearance of low quality individuals from older age classes may mask senescent declines in the performance of longer-lived individuals. Moreover, the physiological mechanisms that underpin within-individual changes in performance are not well understood. Unravelling the drivers of such age-related variation requires longitudinal data, following individuals throughout their lives, which presents challenges for the study of natural populations. Albatrosses are among the longest lived vertebrates. In this thesis, I use data from three species of albatross breeding at Bird Island, South Georgia (54°00’S, 38°03’W) to explore age-related variation. Focusing primarily on the wandering albatross, Diomedea exulans, I characterise the relationship between age and various reproductive traits, and decompose the population-level patterns to reveal effects of experience, senescence and terminal effects across the reproductive lifespan of individuals. I then consider foraging behaviour as a proximate driver of changes in reproductive performance in this species. Using tracking data collected over a 20 year period, I find limited evidence for age-related variation in foraging trips taken throughout the breeding cycle. Going one step further, I explore telomere dynamics in the wandering albatross, examining the potential for telomere length to act as a physiological marker of individual state. Finally, I move on to a species comparison, incorporating data from the black-browed (Thalassarche melanophris) and grey-headed albatross (Thalassarche chrysostoma). I compare the population- and individual-level ageing patterns of these three closely related species, and consider these in light of their differing life history strategies.
92

Essays on the impact evaluation of education policies in Mexico

Cabrera Hernández, Francisco-Javier January 2016 (has links)
This thesis gathers research on three impact evaluations of interventions at the school and student level in Mexico. The first chapter evaluates the effects of a School Breakfast Program (SBP) on children's outcomes such as cognitive skills, illness, height and weight and grade repetition in the period 2002 to 2005. Quasi-experimental estimations provide evidence of positive effects on children's weight; however, such gains push children over their 'ideal' standardized average causing them overweight. This effect is significantly higher in the case of poorer children. The second chapter evaluates a Full-Time Primary Schools Program implemented in 2007, to work out if changing the time pupils spend at school can enhance skills in language and mathematics. Differences in Differences regressions point to a significant improvement of 0.11 standard deviations in mathematics and Spanish test scores after four years of treatment. These gains are three times higher in schools located in deprived areas and do not seem to be driven by students self-selection. The last chapter focuses on an exogenous policy change in Mexico which eliminates enforced grade repetition for all first to third grade students. This reform helped schools to reduce repetition rates from varying higher levels to almost zero in one academic year. Estimations coming from two-way fixed effects models using a panel of schools show an average reduction in dropout rates after reform implementation of 0.3% points along with no seeming effects on pupil's performance. General findings from the three chapters are of strong significance when placed into the broader debate about what works best in schools for improving children's academic performance and general education outcomes in Mexico.
93

Gendering international student mobility : an Indian case study

Sondhi, Gunjan January 2013 (has links)
This thesis explores the dialectical relationship between gender and international student mobility (ISM). The focus is on the experiences of Indian students across three space-time locations: before the students left India; while abroad in Toronto; and their return to New Delhi. The value of this research is two-fold. Firstly, my research helps to fill the lacuna in ISM research that examines the phenomenon through a gender optic. Secondly, there is increasing interest in Canada and other countries – evident in the media and government policy – in international students from India. The study is located at the nexus of gender and mobility scholarship; it adopts Gendered Geographies of Power as a foundational framework. The research employed a multi-sited, mixed-methods approach to data collection. The data collection in the field sites of Toronto, Canada and New Delhi, India consisted of in-depth semi-structured interviews and participant observations. An online survey was mounted for the duration of the fieldwork to gather data on the broader population of Indian students abroad. The results of this survey provide context for the discussion in three empirical chapters. The first of the three empirical chapters explores the impact of gender relations in shaping motivations to study abroad. The second chapter examines how relations of power in and across multiple spaces (re)shape the students‟ performances of gender identities in everyday life in Toronto. The final empirical chapter examines the students‟ experience of return mobility as they attempt to adapt to a different (but familiar) gender context again. My research contributes to the growing body of scholarship on ISM as well as that on gender and migration. By employing a gendered perspective, the indepth interviews as well as ethnographic research reveals the shifting subjectivities of the migrants as they simultaneously negotiate multiple ethnic and kinship interactions in their everyday lived experiences. Secondly, the online survey presents the gendered class configurations of the socio-economic background of the Indian international students. Lastly, the „return‟ experiences of the students are differentiated by gender: more women than men found it harder to (re)negotiate their gender-expected performances in New Delhi. Furthermore, the „return mobility‟ of men appears to be more permanent than the return mobility of women.
94

Imigrace jako prostředek pro řešení demografické krize v Japonsku / Immigration as a possible solution for the current demographic crisis in Japan

Sheretova, Maria January 2011 (has links)
The main goal of this thesis is to analyze the current demographic situation in Japan (mainly to explore the processes of migration in Japan and its impact on the demographic situation in the country). Specifically, this thesis analyzes the current demographic crisis and migration processes over the past century and then demonstrates, on the basis of theoretical knowledge, possible solutions to this crisis within the context of the premise of possible future development through external migration as a priority solution.
95

Avaliação clínica de pacientes com distonia idiopática / Clinical evaluation of patients with idiopathic dystonia

Torben Cavalcante Bezerra 03 May 2016 (has links)
INTRODUÇÃO: A distonia é caracterizada por contrações musculares sustentadas, frequentemente gerando movimentos de torção, repetitivos ou posturas anormais. A classificação de distonia é baseada em três eixos: idade de início, distribuição e etiologia. A definição criada pelo Comitê da Fundação de Pesquisa Médica em Distonia, em 1984, ainda está em uso atualmente. Questionamentos têm sido feitos para uma nova proposta de classificação de distonia. MATERIAIS E MÉTODOS: Trata-se de um estudo transversal descritivo de uma série de pacientes com diagnóstico de distonia primária e distonia-plus acompanhados em uma clínica brasileira especializada em distúrbios do movimento, no período de março de 2015 até fevereiro de 2016. Foi realizada a coleta de dados demográficos, clínicos e da gravidade da distonia. Os pacientes foram reavaliados e reclassificados segundo a nova proposta de classificação para as distonias. Utilizamos métodos descritivos para apresentarmos as características da amostra, o teste de Shapiro-Wilk para distribuição normal, o teste de Kruskal-Wallis para comparar grupos independentes e variáveis sem distribuição normal e o teste do X2 para comparar variáveis nominais. RESULTADOS: Dos 289 pacientes, foram 235 pacientes avaliados segundo a distribuição corporal, sendo blefaroespasmo 60 pacientes (26%), distonia cervical 51 pacientes (22%), distonia de membro 28 pacientes (12%), distonia laríngea 10 pacientes (4%), distonia oromandibular 3 pacientes (1%), distonia segmentar 46 pacientes (20%), distonia multifocal 23 pacientes (9%) e distonia generalizada 14 pacientes (6%). Foram 227/235 (97%) pacientes com distonia primária e 8 (3%) pacientes com distonia-plus. Houve maior prevalência no sexo feminino com 144 pacientes. Os pacientes com distonia generalizada, multifocal, distonia dopa-responsiva e distonia-parkinsonismo tiveram a idade de início da distonia inferior a todos os demais grupos (p=0,0001). Os pacientes com distonia do membro superior e distonia tarefa-específica tiveram a idade de início da distonia inferior às outras distonias focais e distonias segmentares (p=0,0001). Os pacientes com distonia tarefa-específica e distonia focal do membro superior têm escolaridade superior aos demais grupos (p=0,0001). Em média, foram 5±7,8 anos para o diagnóstico definitivo de distonia e 2±1,5 médicos até que o diagnóstico de distonia fosse confirmado. O truque sensorial foi mais frequente na distonia cervical 30/51 (59%) pacientes. Segundo a nova classificação, encontramos apenas mudança de resultados na distonia multifocal com 21/235 (9%) pacientes e na distonia generalizada com 16/235 (6%) pacientes. Foram 164/235 (70%) pacientes na faixa etária maior que 40 anos. Todos os pacientes tiveram curso da doença com padrão estático e a maioria com variabilidade persistente em 186/235 (79%) pacientes. Foram 227/235 (97%) pacientes com distonia isolada. Nenhum paciente apresentou lesão adquirida ou degenerativa. Foram 211/235 (90%) pacientes que apresentaram diagnóstico etiológico idiopático esporádico. CONCLUSÃO: A nova classificação de distonia não apresentou novos benefícios na prática clínica diária, comparada com classificações anteriores. O benefício maior foi uma reorganização e formação de novas definições e critérios para atividade de pesquisas científicas e identificação de casos mais raros. / INTRODUCTION: Dystonia is characterized by sustained muscle contractions, frequently causing twisting movements, repetitive or abnormal postures. Dystonia rating is based on three axes: age of onset, distribution and etiology. The definition established by the Committee of the Medical Research Foundation in dystonia in 1984, is still in use today. Claims have been made for a new proposal for dystonia rating. MATERIALS AND METHODS: This is a descriptive cross-sectional study of a number of patients with primary dystonia and dystonia-plus assisted in a Brazilian clinic specializing in movement disorders, from March 2015 to February 2016 data collection was performed demographic, clinical and severity of dystonia. The patients were re-evaluated and reclassified according to the new proposed classification for dystonia. We used descriptive methods to present the characteristics of the sample, the Shapiro-Wilk test for normal distribution, the Kruskal-Wallis test to compare independent groups and variables without normal distribution and the X2 test to compare nominal variables. RESULTS: Of the 289 patients, there were 235 patients evaluated according to body distribution, with blepharospasm 60 patients (26%), cervical dystonia 51 patients (22%), a member of dystonia 28 patients (12%), laryngeal dystonia 10 patients (4%), oromandibular dystonia 3 patients (1%), segmental dystonia 46 patients (20%), dystonia multifocal 23 patients (9%) and generalized dystonia 14 patients (6%). Were 227/235 (97%) patients with primary dystonia and 8 (3%) patients with dystonia-plus. There was a higher prevalence in females with 144 patients. Patients with generalized dystonia, multifocal, dopa-responsive dystonia and dystonia-parkinsonism had the age of onset of dystonia lower than all other groups (p = 0.0001). Patients with dystonia of the upper limb and task-specific dystonia had the early age of less dystonia other focal dystonias and segmental dystonia (p=0.0001). Patients with task-specific dystonia and focal upper limb dystonia have higher education to other groups (p=0.0001). On average, there were 5 ± 7.8 years for the definitive diagnosis of dystonia and 2 ± 1.5 doctors until the diagnosis of dystonia were confirmed. The sensory trick was more frequent in cervical dystonia 30/51 (59%) patients. According to the new classification, we found only change results in multifocal dystonia with 21/235 (9%) patients and generalized dystonia with 16/235 (6%) patients. Were 164/235 (70%) patients aged greater than 40 years. All patients had disease course with static standard and most with persistent variability in 186/235 (79%) patients. Were 227/235 (97%) patients with dystonia isolated. No patient had acquired or degenerative injury. Were 211/235 (90%) patients with sporadic idiopathic etiologic diagnosis. CONCLUSION: The new dystonia rating showed no new benefits in clinical practice compared with previous ratings. The greatest benefit was a reorganization and training of new definitions and criteria for scientific research activity and identification of rare cases.
96

Influences on Foster Care Reentry Rate

Morris, Ashley L, Battista, Andrew, Achilov, Dilshod, Keeler, Rebecca L 01 May 2014 (has links)
Influences on Foster Care Reentry Rate looked at demographic and socioeconomic characteristics in each state within the United States. Those characteristics were then studied to see how they related to foster care reentry rates. Then, a case study analysis was conducted on three states, Minnesota, North Carolina, and Tennessee, because of their similarity in demographic and socioeconomic characteristics and divergence in foster care reentry rates. The case analysis was an in depth pursuit of differences in each of the state's policies that may be a driving force of higher reentry rates.
97

Baker Act Examination Referrals Among Children and Adolescents: An Analysis of School Related Variables

Beam, Bradley Scott 22 March 2007 (has links)
The Baker Act is legislation that provides civil rights for individuals suspected of having a mental illness and may be in need of involuntary psychiatric evaluation. Its intent is to prevent the indiscriminate placement of individuals in residential treatment facilities and other restrictive placements. Referrals for involuntary psychiatric evaluation under Baker Act statutes have increased among children and adolescents in recent years, raising concerns related its use with this population. The purpose of this study was to explore the relationship between school based factors and the use of the Baker Act among children and adolescents. Results indicate that the use of the Baker Act is more prevalent receiving among the high school population, females, Other/mixed children and adolescents, and White children and adolescents. Multiple regression analyses indicated that school district variables (e.g., minority enrollment, graduation rates, out-of-school suspension, etc.) contributed to a statistically significant proportion of the variance in Baker Act ER rates and repeat Baker Act ER rates among the 67 counties in the state of Florida. The percent of students in a district that graduated with a standard diploma was the variables that most consistently contribute to a unique proportion of the variance in Baker Act ER and repeat Baker Act ER rates. The findings from the study have implications for the design of mental health and behavioral support systems for children and adolescents. Additional research is necessary to more closely examine the relationship between demographics, school related variables, and the use of the Baker Act.
98

Plant Demographics Studies of Tall Threetip Sagebrush-Grass Vegetation on the Eastern Snake River Plains, Idaho

Rea, Kenneth Harold 01 May 1976 (has links)
It has commonly been assumed that grazing decreases the longevity of plants, however, very few studies address this question. Knowledge of mean age, longevity and other aspects of population dynamics would help improve estimates of productivity and nutrient cycling and aid understanding of range condition and trend. These data would also aid in developing a theory of community organization and control. As a step toward these ends, pantograph records from twelve 1 m2 plots established at the U. S. Sheep Station on the Snake River Plains of southeastern Idaho between 1923 and ' l935 were examined. The plots were mapped almost yearly until 1956. These records were analyzed for establishment and survival of populations of major vascular, perennial plant species of the tall threetip sagebrush-grass vegetation type. Average longevities of the grazed plants were significantly different from ungrazed populations for some species. For the pastures grazed by sheep in the fall the average longevities of the dominant grass and two subdominant grasses were increased whereas the average longevity of tall threetip sagebrush was reduced by grazing. The differences in average longevity due to grazing are thought due to alteration of competitive relationships. The photosynthetically active sagebrush is sensitive to grazing in the fall whereas the grasses are dormant. A slight reduction in the total volume of the sagebrush apparently releases resources to the grasses the following spring. The greatest mortality was observed during the first year of life for all species . Survivorship curves for the first eleven years of life of most species could be linearized by logarithmic transformations on both axes indicating that the chance for survival improved with age, up to the physiological maximum. No linear relationships of increasing size to age were found in these plants. This indicates a considerable plasticity in the growth characteristics of these plants, where in poor years negative growth can occur by the reduction of unsupportable biomass. This all ows plant size to fluctuate with fluctuating environment, and allows for stands of even sized plants with great age differences. Labeling recruitment to these plant populations as "pulse" phenomena becomes a matter of definition. If a log-normal distribution is expected, as indicated by some researchers, outliers are not present and "pulse" regeneration does not occur in this system. However, if recruitment is expected to follow a normal distribution then the years with high numbers of seedlings become "pulses," by definition. From these analyses, it appears that these semi-desert communities are closed (the available resources are totally used) and replacement of individuals is somewhat random following more or less random death.
99

Burden of Care: Ageing in urban China and Japan: Gender, the family and the state

Miller, Elizabeth Jill, res.cand@acu.edu.au January 2002 (has links)
This thesis examines how rapid demographic, social and economic changes are impacting on traditional care for the urban aged in China and Japan as both experience world record rates of ageing caused by greater longevity and lower birth rates. The challenge for their governments is to foster active contribution by the healthy aged to society and protection for the frail aged. China lags behind Japan in special treatment for senior citizens. The manner in which these two countries handle the ageing of their populations could provide valuable lessons for Australia in the future.
100

An analysis of future directions for victorian coastal residential property - exploring the myths.

Robson, Kathryn Mary, Kathryn.robson@rmit.edu.au January 2008 (has links)
This research provides an analysis of the disparate notions and ideas, to form an overview of the possible trends in residential property for the Victorian coastal areas of the Surf Coast and the Bellarine Peninsula. It examines the interaction of the consumers, space producers and infrastructure providers as they are influenced by the three key determinants of the market, the demographic factors, economic conditions and statutory factors. While examining the patterns of urban development on coastal Victoria over the next 20 years, the research also investigates the validity of myths that have emerged concerning the Sea Change experience, the investment market in coastal areas and the adequacy of the relevant infrastructure. The qualitative data used in this research comes from both primary and secondary sources. The primary qualitative and quantitative data was developed on the basis of the responses to a mail out questionnaire to residents from seven towns on the Bellarine Peninsula and the Surf Coast and from a number of interviews with local property experts from these areas. The secondary qualitative and quantitative data came from the results of various government surveys, demographers, the press and the census. The main thrust of this research is to answer the question

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