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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.
21

Crescimento e reprodução do peixe anual Austrolebias wolterstorffi (cyprinodontiformes:rivulidae) em diferentes temperaturas

Fonseca, Alinca Peres da January 2011 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2011. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-08-08T14:54:23Z No. of bitstreams: 1 dissertao alinca em pdf termo de autorizao bdtd-1 para publicao de tese e dissertao.pdf: 1746700 bytes, checksum: 78e5fc34be747f883e7353aba07d089e (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-11-06T22:18:14Z (GMT) No. of bitstreams: 1 dissertao alinca em pdf termo de autorizao bdtd-1 para publicao de tese e dissertao.pdf: 1746700 bytes, checksum: 78e5fc34be747f883e7353aba07d089e (MD5) / Made available in DSpace on 2012-11-06T22:18:14Z (GMT). No. of bitstreams: 1 dissertao alinca em pdf termo de autorizao bdtd-1 para publicao de tese e dissertao.pdf: 1746700 bytes, checksum: 78e5fc34be747f883e7353aba07d089e (MD5) Previous issue date: 2011 / A temperatura é um parâmetro que influencia na dinâmica de fatores bióticos, especialmente nos animais ectotérmicos. O ciclo de vida dos peixes anuais é afetado pela temperatura da água. Devido à fragilidade do habitat destes peixes à ações antrópicas, ameaça de extinção, importância dos mesmos como modelos biológicos e a lacuna no conhecimento da sua biologia, este trabalho tem como objetivo o estudo da influência da temperatura no crescimento e na reprodução de Austrolebias wolterstorffi. Logo após a eclosão foi dado início ao ensaio de crescimento em diferentes temperaturas, 16, 20, 24 e 28°C (todas com três repetições), com duração até os 67 dias de vida dos peixes. O presente trabalho evidenciou que a manutenção em 28°C é prejudicial ao crescimento de A.wolterstorffi no âmbito do período estudado Dentre as demais temperaturas testadas, foi verificado que a temperatura ótima para o crescimento diminui ao longo da vida, onde no inicio do ciclo, durante a fase juvenil, temperaturas mais elevadas (23,8° C) favorecem o crescimento, enquanto temperaturas intermediárias otimizam o crescimento de fêmeas (20,7°C) e machos (20,1°C) adultos. A temperatura ótima para o crescimento foi sempre ligeiramente inferior para os machos. O comprimento e o peso corporal demonstraram ser mais representativos na diferenciação do que a idade, pois os peixes com crescimento mais lento demoraram mais a diferenciar. Os machos crescem mais rápido que as fêmeas e, portanto, atingem a maturidade antes. Os ensaios de reprodução foram constituídos dos mesmos tratamentos do experimento de crescimento, porém as 12 UE foram dotadas de casais. Foram fornecidos ninhos para postura de ovos. De maneira geral, as fêmeas tratadas a 24°C apresentaram melhores resultados, pois além de manter o fator de condição (K) relativamente elevado, obtiveram altas taxas de fertilidade (FT) e fecundidade (FC). Dados registrados para K, FT, FC, índice gonadossomático e histologia dos testículos evidenciaram que o desempenho reprodutivo foi prejudicado na temperatura mais elevada. Portanto, os resultados do presente estudo sugerem que 24°C é a temperatura mais indicada para manter A. wolterstorffi durante todo o ciclo em cativeiro. / Temperature is especially important for the dynamics of biotic factors in poikilothermic animals. Life cycle of annual fish is affected by temperature. These fish inhabit fragile environments, susceptible to antropic actions, and as such some species are threatened with extinction. They are also important as biological models, but information on their bio-ecology is scarce. The aim of this work was to investigate the influence of temperature on growth and reproduction of Astrolebias wolterstorffi. Soon after hatching fish were exposed to 16, 20, 24 and 28°C, and their growth was followed for 67 days. Until 18 d.a.h (days after hatching) the growth is hampered at 16°C and do not show difference at 20, 24 and 28°C. Thereafter, the intermediate temperatures favor growth of juveniles, while extremes temperatures are prejudicial. After sexual differentiation, growth was improved for fish reared at 16°C, and reduced at 28°C. There is evidence suggestin that optimal growth temperature decrease with fish age. Juveniles grow faster at high temperature (23,8°C), whereas intermediate ones optimize the growth adults females (20,7°C) and males (20,1°C). Growth of males is higher at slightly lower temperatures than that optimal for growth of females. Maturation onset is defined by length rather than age, and at high temperatures maturation is observed earlier. Also, males mature earlier than females. For the reproduction study, 12 couples (150 d.a.h.) were distributed in 12 tanks at the same temperatures of the growth experiment. Reproduction output was favored when A. wolterstorffi were kept at 24°C. Furthermore, fish kept at 28°C presented the worst reproductive parameters, including condition factor, fertility, fecundity, gonadosomatic index, and also histological evidence. The results of the present studies suggest that A. wolterstorffi should be reared at 24°C during the whole cycle in captivity.
22

Le féminin dans les paysages pré-chrétiens irlandais / The feminine in Irish pre-Christian landscapes

Onda, François-Joseph 06 July 2012 (has links)
La présente étude s’intéresse aux popula-tions installées en Irlande avant l’arrivée du christianisme (aux environs du Ve siècle de notre ère), et plus précisément aux bâtisseurs des tombes à couloirs du Néolithique ainsi qu’aux Celtes. L’omniprésence d’une com-posante féminine symbolique dans les pay-sages pré-chrétiens (qu’ils soient naturels, mégalithiques ou littéraires) est au centre de cette analyse, qui prend en considération le caractère matrifocal des sociétés archaïques et en évalue l’impact sociétal et rituel chez les Celtes. La thèse examine la spécificité de la perception des reliefs et l’expression sym-bolique de la représentation. Cette dernière se traduit chez les populations du Néolithique par une féminisation du paysage au travers des modifications délibérées de lieux naturels ou la création de sites clefs (tels que Brú na Bóinne ou Loughcrew). Nous montrons aussi que cette perception de l’espace comme fé-minin fut relayée chez les Celtes par la créa-tion de mythes mettant en scène des figures féminines divines ou évhémérisées transfonc-tionnelles. Le rapprochement proposé entre les créa-tions de ces deux groupes humains distants de plusieurs millénaires (de - 3500 à 700) vise à montrer qu’il existe dans les deux cas conception similaire de la terre d’Irlande comme féminine. Pour ce faire, la thèse met en relation plusieurs disciplines. La confron-tation des documents archéo-mythologiques révèle une continuité chronologique dans les représentations qui est liée à l’assimilation de l’héritage culturel indigène par les Celtes venus du continent. Nous avançons l’idée que l’osmose entre ces deux cultures a donné naissance à une identité celte insulaire unique, fortement ancrée dans la terre d’Irlande. / This study deals with the peoples who settled in Ireland before the coming of Chris-tianity (around the 5th century C.E.), and more precisely with both the builders of pas-sage tombs dating from the Neolithic period and the Celts. The analysis revolves around the omnipresence of a symbolical feminine element in pre-Christian landscapes (be they natural, megalithic or literary) and takes into account the matrifocal nature of these ancient communities, assessing its impact on Celtic societies and rituals. A specific apprehension of the natural features and its symbolic repre-sentation will be examined here. The latter is expressed by the Neolithic peoples through feminine sexual attributes they deliberately added to natural places or through the promi-nent sites they built (such as Brú na Bóinne or Loughcrew). It will also be shown that such a feminine perception of the Irish land-scape was taken up by the Celts, who created myths involving transfunctional or euhemer-ised goddess figures. Bringing together the creations of these two peoples separated by several millennia (from 3,500 B.C.E. to 700 C.E.) aims at showing that they shared a similar feminine vision of Ireland. To do so, several fields will be considered. Confronting archaeo-mythological documents will highlight actual chronological consistency in representation. This is linked to the continental Celts’ assim-ilation of the indigenous cultural heritage. We believe that the blending of these two cultures led to a unique insular Celtic identity which is deeply rooted in the land of Éire.
23

Effects of Maternal and Neonatal Hypoxia on the Future Life History of Daphnia magna

Lowman, Rachael 01 December 2021 (has links)
Early exposure to hypoxia is related to a variety of physiological and metabolic changes that have lasting effects on organisms’ physiology and life history. We measured the effects of maternal and embryonic mild, intermittent hypoxia on the life history of four clones of microcrustacean Daphnia magna, an emerging model organism for the studies of senescence and longevity. Daphnia individuals were produced parthenogenically, maintained in individual vials, and fed standard algal concentration daily. The cohort consisted of 189 individuals. We measured body size at first reproduction, fecundity (including late-life fecundity peak), offspring sex ratio, and longevity. We found no effect of maternal and embryonic hypoxia on body size and longevity; however, there was a slight but statistically significant increase in age-specific mortality in the early hypoxia treatment cohort. Daphnia from the hypoxia group showed higher early fecundity which disappeared by the age of 100 days. A late-life spike in fecundity was observed at the age of 100 days when hypoxia group individuals showed significantly lower fecundity. There was little evidence of a trade-off between early- and late-life fecundity. Finally, early hypoxia affected mid-life male production in one of the four clones, and we discuss possible physiological changes triggered by maternal and embryonic exposure to hypoxia.
24

Environmental and psychosocial risk factors for subfertility

Wesselink, Amelia Kent 30 June 2018 (has links)
Fecundity, defined as the biologic capacity for reproduction, is measured operationally as time-to-pregnancy (TTP) among non-contracepting couples. While most couples conceive naturally within six menstrual cycles of trying, 10-24% of couples take longer than six cycles. Fecundity impairments are associated with long-term adverse health consequences including insulin resistance and gynecologic cancers, can cause substantial psychological and economic hardship, and cost over $5 billion annually in the U.S. Therefore, identifying risk factors for subfecundity in order to increase the chances of natural conception among pregnancy planners is an important public health goal. Environmental and psychosocial risk factors are understudied in relation to reproductive health. The goal of this dissertation is to examine the independent associations between exposure to tetrachloroethylene, perceived stress, and cigarette smoking and fecundability, the per cycle probability of conception. In study one, we used data from a retrospective cohort study of Cape Cod women who were exposed to tetrachloroethylene-contaminated drinking water in the 1960s-1980s to examine the relation between tetrachloroethylene exposure and fertility. We found that women with the highest modeled tetrachloroethylene exposure around the time of the pregnancy attempt had increased risk of TTP>12 months compared with unexposed women. Cumulative exposure, however, was not associated with elevated risk of TTP>12 months. Studies two and three used data from Pregnancy Study Online (PRESTO), a preconception cohort study of pregnancy planners from North America. In study two, we found that perceived stress levels in women, but not their male partners, were associated with lower fecundability, with little evidence of mediation by measured behavioral factors. In study three, we found that male current active smoking was associated with lower fecundability. In women, current smoking was only associated with reduced fecundability among women who smoked with high intensity and/or long duration. Passive smoking was not substantially associated with fecundability in either partner, but women exposed in utero to high intensity smoking had lower fecundability than unexposed women. Overall, we observed weak associations between tetrachloroethylene exposure, perceived stress, and active smoking and fertility among pregnancy planners. These findings indicate that environmental and psychosocial factors may play a role in the etiology of infertility. In addition, given that these exposures are common and modifiable, they may be important targets for public health interventions.
25

The Effect of a Single Cold Stress on the Mating Behavior, Agonistic Behavior, and Gut Microbiome of Male Acheta domesticus Crickets

Chipchase, Kathryn Marie 22 November 2022 (has links)
No description available.
26

Energy balance, health and fecundity among Bhutia women of Gangtok, Sikkim, India

Williams, Sharon R. 16 October 2003 (has links)
No description available.
27

Plant nectar contributes to the survival, activity, growth, and fecundity of the nectar-feeding wandering spider Cheiracanthium inclusum (Hentz) (Miturgidae)

Taylor, Robin M. 21 June 2004 (has links)
No description available.
28

Life History of the Common Bed Bug Cimex lectularius L. in the U.S.

Polanco, Andrea M. 15 April 2011 (has links)
This study quantifies the rate of bed bug nymphal development, mortality, fecundity and survivorship during starvation for wild caught resistant populations. I then compare some of these characteristics with two susceptible strains. I found that resistant populations develop faster and exhibit less mortality per life stage than susceptible populations. However, there were no significant differences in the total number of eggs produced by the resistant females from the field strains during the 13 feedings/oviposistion cycles (P = 0.106). On average, resistant females from the field strains produced 0.74 eggs per day. Susceptible strains survived a significantly longer time without feeding (89.2 d and 81.4 d) than the resistant strains (RR, ER). The mean duration of adult life (from the day the female becomes an adult until the day she dies) for (RR) strains was 118.7 d ° 11.8 SE. The intrinsic rate of increase r or average daily output of daughter eggs by female was 0.42. The net reproductive rate Rₒ, indicated that one live female egg would, on the average, be replaced by approximately 35 females. Resistant and susceptible populations were found to be different in terms of development, survivorship, and fecundity. The differences between susceptible and resistant strains could be explained by a trade-off between the alleles that confer resistance and the fitness in the population. When compare the stable age distribution of a pyrethroid susceptible strain (HS) and a resistant strain (RR) there were not significant differences (?°= 9.0066, df = 6, P = 0.1732) in the stable age distribution, basically both strains were dominated by the egg stage. No significant difference was found in the expected reproductive contribution of the various life stages to future population size between the two strains (?°= 1.5458, df = 6, P = 0.9564). Despite this, the reproductive contributions of life stages other than eggs were generally higher for the HS strain than for the RR strain. For both strains changes in P? for the adult stage are expected to have the greatest impact on?? compared with changes in P? for the other life stages. The key to the reduction of the populations of bed bugs lies with the reduction of survival of the adults. / Master of Science in Life Sciences
29

AvaliaÃÃo de desova induzida hormonalmente e qualidade dos ovos de ariacÃ, Lutjanus synagris (LINNAEUS, 1758) / Assessment of hormonally induced spawning and egg quality of ariacÃ, Lutjanus synagris (Linnaeus, 1758)

Oscar Pacheco Passos Neto 16 November 2010 (has links)
O presente estudo teve como objetivo avaliar a desova induzida hormonalmente e a qualidade dos ovos do ariacÃ, Lutjanus synagris. Foram avaliadas as fecundidades absoluta e relativa, o diÃmetro dos ovos e de suas respectivas gotÃculas de Ãleo, a porcentagem de ovos flutuantes, a taxa de fecundaÃÃo, a taxa de eclosÃo e sobrevivÃncia das larvas apÃs consumo da reserva vitelÃnica. O estudo foi desenvolvido no Centro de Estudos Ambientais Costeiros (CEAC) do Instituto de CiÃncias do Mar (LABOMAR) da Universidade Federal do Cearà (UFC). IndivÃduos juvenis foram capturados na natureza por meio de pesca com anzol, levados ao laboratÃrio e mantidos sob quarentena. Para finalizar o processo de maturaÃÃo gonadal os indivÃduos foram transferidos para o sistema interno, mantidos sob fotoperÃodo de 14 horas de claro e alimentados alternadamente com sardinha, camarÃo e lula. ApÃs a verificaÃÃo da maturaÃÃo gonadal foi iniciado o perÃodo de induÃÃo hormonal. Os animais foram capturados, anestesiados, medidos e pesados. O critÃrio de maturidade utilizado foi liberaÃÃo de sÃmen para os machos e diÃmetro mÃdio dos ovÃcitos maior que 400 μm para as fÃmeas. As induÃÃes ocorreram entre os meses de novembro de 2009 e marÃo de 2010 com injeÃÃes de gonadotrofina coriÃnica humana (hCG) na base da nadadeira peitoral. Foram utilizadas doses de 1.500 UI kg-1 e avaliados dois protocolos. No Protocolo 50/50 foram aplicadas duas injeÃÃes contendo 50% da dose total e no Protocolo 70/30 a primeira dose foi de 70% e a segunda de 30% da dose total. A segunda injeÃÃo foi aplicada 24 horas apÃs a primeira. Os machos receberam dose Ãnica de 750 UI de hCG kg-1 no momento da segunda injeÃÃo na fÃmea. A proporÃÃo sexual (fÃmea:macho) utilizada foi de 1:2. A porcentagem de ovos flutuantes apresentou diferenÃa significativa com valores mÃdios de 78,18  39,71% e 33,68  41,02% para os Protocolos 50/50 e 70/30, respectivamente. NÃo foi observada diferenÃa significativa para nenhum dos demais parÃmetros avaliados. Os valores mÃdios para fecundidade relativa foram de 306.815,10  135.218,18 Ãvulos kg-1 (Protocolo 50/50) 404.511,27  261.545,16 Ãvulos kg-1 (Protocolo 70/30). A fertilizaÃÃo dos ovos flutuantes variou entre 92 e 100% com diÃmetro mÃdio de 726,0  16,89 μm a 795,0  19,43 μm e da gotÃcula de Ãleo de 122,5  8,07 μm a 141,5  11,89 μm. A eclosÃo ocorreu em 16 horas sob temperatura mÃdia de 29,3  0,9oC. Ovos com mÃltiplas gotÃculas de Ãleo apresentaram eclosÃo e sobrevivÃncia similares Ãqueles com uma gotÃcula. O ariacà se mostrou uma espÃcie que se adapta bem ao cativeiro respondendo positivamente ao manejo e à induÃÃo hormonal. Os resultados positivos mostram que o hCG à eficaz na reproduÃÃo induzida desta espÃcie, contudo a variabilidade dos dados encontrados no presente estudo revela que a tÃcnica precisa ser aprimorada / The aim of this study was to evaluate the hormone induced spawn and egg quality of lane snapper, Lutjanus synagris. The absolute fecundity, relative fecundity, egg and oil globule diameter, percentage of floating eggs, percentage of fertilization, hatching rate and larval survival up to yolk consumption were assessed. The study was conducted at Centro de Estudos Ambientais Costeiros (CEAC) from Instituto de CiÃncias do Mar (LABOMAR) from the Universidade Federal do Cearà (UFC). Wild juveniles were captured by hook, took to the laboratory and held in a quarantine system. Fishes were transferred to the internal system to complete gonadal maturation under a 14h-light photoperiod and fed fish, shrimp and squid. After gonadal maturation, induced spawn period was started. Individuals were captured, anesthetized and measured. Maturity criteria were running milt for males and mean oocyte diameter greater than 400 μm for females. Induced spawns were attempted in the period between November 2009 and March 2010, by using human chorionic gonadotropin (hCG) injections at the base of the pectoral fin. Total doses of 1.500 IU kg-1 were used and two experimental protocols were evaluated. In the Protocol 50/50, injections of hCG were given in two doses of 50% of total dose while in the Protocol 70/30, the first dose was 70% and the second was 30% total dose. The second injection was given after 24 hours. Males received only one injection of 750 IU kg-1, at the time of the second injection to females. The sex ratio (female:male) was 1:2. The percentage of floating eggs was significantly different, with mean values of 78.18  39.71% and 33.68  41.02% for Protocols 50/50 and 70/30, respectively. There were no significant differences in any other evaluated parameters. The mean values of relative fecundity were 306,815.10  135,218.18 egg kg-1 (Protocol 50/50) and 404,511.27  261,545.16 egg kg-1 (Protocol 70/30). The percentage of fertilization in floating eggs ranged from 92 to 100% with mean egg diameters from 726.0  16.89 μm to 795.0  19.43 μm and oil globule diameters from 122.5  8.07 μm to 141.5  11.89 μm in Protocols 50/50 and 70/30. Hatching occurred 16 hours after spawning at mean temperature of 29.3  0.9oC. Spawns with eggs having multiple oil globules had a similar hatching rate and larval survival than those with simple oil globule. Lane snapper can successfully adapt to captivity conditions and positively respond to handling and induced spawn. The positive results show that hCG induced spawn is feasible, however the variability of the found data in the present study reveals that this technique needs to be improved
30

Effects of Bt crop residues on the development, growth, and reproduction of the freshwater snail, Bulinus tropicus / Karin Minnaar

Minnaar, Karin January 2014 (has links)
Genetically modified (GM) crops were introduced in South Africa in 1989 and commercially available by 1998. Legislation to control the use of GM crops was only implemented in 1999, with the genetically modified organisms (GMO) act (15 of 1999). In 2012 2.9 million ha of GM crops were planted in South Africa alone. GM Crops, such as Bt maize, are promoted as safer for the environment since no chemical pesticides are needed. However, recently GM crops have been making headlines as more and more studies find adverse effects of these crops on non-target organisms. The effects on aquatic environments have not yet been fully determined, even though traces of Bt residue have been found in water systems surrounding agricultural lands. The aim of this study was to establish the effects of the Bt toxin on fecundity, development and growth of Bulinus tropicus, a freshwater snail. The experiment made use of a static renewal tests to expose B. tropicus to 50 cm2 Bt maize and cotton leaves in 900 ml of synthetic freshwater. The snails were exposed for the duration of one full life cycle (embryo to adult). Endpoints measured included the development, growth, fecundity, and deformities of the reproductive organs. The results obtained showed retarded development and low embryo survival when the snails were exposed to cotton leaves, irrespective of the presence or absence of Bt, indicating to the possibility of trace residues of chemical pesticides may have been present on the leaves. Initial stimulated growth of hatchlings was observed for both Bt cotton and maize exposures, but after sexual maturity has been reached, ‘surplus’ energy was probably shared between growth and fecundity, resulting in a reduction of growth rate. Energy is gained from their diet, thus a sub-optimal diet would result in less energy available to functions such as growth and fecundity. Signs of developmental instability were found in the formation of the shell opening of the snails exposed to Bt. Fecundity decreased significantly after snails had been exposed to Bt maize / cotton leaves. No differences were found in the penis sheath-preputium length ratio, indicating that Bt had no deleterious effects on the reproductive organs. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

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