997 resultados para Bichat, Xavier (1771-1802)


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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1. 1. Oxygen consumption and its relationship to stepwise declining oxygen tension were examined in the common striped hermit crab, Clibanarius vittatus. 2. 2. Weight-specific oxygen consumption varied with body weight (W), according to the equation log V ̇o2 = 2.1639 + (-0.419 log W). 3. 3. Shell-less individuals of 1-2 g wet wt, where found to be oxygen conformers, since oxygen consumption ( V ̇o2) decreased with declining oxygen tensions. At ambient oxygen tensions below 35.4 mmHg, oxygen consumption remained constant, suggesting an increased ventilation. 4. 4. C. vittatus was found to survive in oxygen-free seawater for 5.5 hr, and no significant differences were found in oxygen consumption rates, for shelled and shell-less crabs, measured in water and air. 5. 5. The use of a K1 K2 index of oxygen independence, showed that larger animals were better able to maintain oxygen-independence during hypoxia than smaller individuals. 6. 6. C. vittatus displayed a pattern of no oxygen debt, once returned to normoxia. © 1983.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The taxonomic status of the species Clibanarius sclopetarius (Herbst, 1796) and Clibanarius vittatus (Bosc, 1802), which have sympatric biogeographical distributions restricted to the western Atlantic Ocean, is based only on differences in the colour pattern of the walking legs of adults. Their morphological similarity led to the suggestion that they be synonymised. In order to investigate this hypothesis, we included species of Clibanarius Dana, 1892 in a molecular phylogenetic analysis of partial sequences of the mitochondrial 16S rDNA gene and the COI barcode region. In addition, we combined the molecular results with morphological observations obtained from several samples of these two species. The genetic divergences of the 16S rDNA and COI sequences between C. sclopetarius and C. vittatus ranged from 4.5 to 5.9% and 9.4 to 11.9%, which did not justify their synonymisation. Differences in the telson morphology, chela ornamentation, and coloration of the eyestalks and antennal peduncle provided support for the separation of the two species. Another interesting result was a considerable genetic difference found between populations of C. vittatus from Brazil and the Gulf of Mexico, which may indicate the existence of two homonymous species.

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Studies of skin wound healing in crocodilians are necessary given the frequent occurrence of cannibalism in intensive farming systems. Air temperature affects tissue recovery because crocodilians are ectothermic. Therefore, the kinetics of skin wound healing in Caiman yacare were examined at temperatures of 33°C and 23°C. Sixteen caiman were selected and divided into two groups of eight maintained at 23°C or 33°C. The studied individuals' scars were photographed after 1, 2, 3, 7, 15 and 30 days of the experimental conditions, and samples were collected for histological processing after 3, 7, 15 and 30 days. Macroscopically, the blood clot (heterophilic granuloma) noticeably remained in place covering the wound longer for the caiman kept at 23°C. Microscopically, the temperature of 23°C slowed epidermal migration and skin repair. Comparatively, new blood vessels, labeled using von Willebrand factor (vWF) antibody staining, were more frequently found in the scars of the 33°C group. The collagen fibers in the dermis were denser in the 33°C treatment. Considering the delayed healing at 23°C, producers are recommended to keep wounded animals at 33°C, especially when tanks are cold, to enable rapid wound closure and better repair of collagen fibers because such lesions tend to compromise the use of their skin as leather.

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In der vorliegenden Arbeit wurde die räumliche und zeitliche Dynamik einer strukturierten Population der Westlichen Smaragdeidechse (DAUDIN, 1802) im Mittelrheintal zwischen 1997 und 2000 untersucht. Dazu wurden die Teilaspekte der Hibernation, der Thermoregulation und der Raumnutzung der Art analysiert. Die Ergebnisse der Hibernation deuten auf eine hohe Relevanz dieses Jahresabschnitts für die Art in Bezug auf die Verbreitung in Südexponierten Steilhanglagen am Nordrand ihrer Verbreitung hin. Die Hibernationsstandorte unterscheiden sich im Mikroklimaprofil von Trockenmauern und Sommerlöchern. Die Standorte der Hibernation liegen in Zonen höchster Insolation im Untersuchungsgebiet. Die Analyse der Thermoregulation zeigte geschlechtsspezifische und saisonale Unterschiede, die mit den unterschiedlichen Jahresaktivitätszyklen erklärt werden können. Die Weibchen zeigen eine engere Bindung an die klimatischen Entwicklungen von Mirkohabitatstrukturen als die Männchen, was mit endogenen Faktoren zusammenhängen könnte. Die Parallelen und Unterschiede zu anderen Arten werden diskutiert. In der Raumnutzung zeigen sich auch Unterschiede zwischen Männchen und Weibchen, die auch mit den unterschiedlichen Jahresaktivitätszyklen erklärt werden können. Im Frühjahr und im Herbst zeigt die Art eine Bindung an Standorte hoher Insolation im Untersuchungsgebiet, im Sommer dagegen keine. In der Gesamtbetrachtung werden die Ergebnisse in Bezug auf das Verbreitungsbild der Art, Schutzaspekte und Schlüsselfaktoren der Habitatqualität diskutiert.

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Lo scopo di questo elaborato è di presentare una proposta di traduzione verso l’italiano del racconto O Verdadeiro Pecado de Xoán Zalzívar della scrittrice portoghese Leonor Xavier, pubblicato all’interno della raccolta Picante – Histórias que ardem na boca. Dopo aver presentato brevemente la biografia e la bibliografia dell’autrice, ci si è soffermati sulla raccolta e sul racconto stesso. In particolare, sono state presentate le tematiche narrate e il filo conduttore della raccolta e successivamente è stata illustrata la trama del racconto. Al centro di questo elaborato vi è la traduzione e la rispettiva analisi. Infatti, è stata rivolta una particolare attenzione alle difficoltà nella resa in italiano, come la ricetta e i suoi ingredienti, le espressioni idiomatiche presenti nel testo di partenza, l’uso delle formule di cortesia e le scelte stilistiche della scrittrice.

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Toxicant inputs from agriculture, industry and human settlements have been shown to severely affect freshwater ecosystems. Pollution can lead to changes in population genetic patterns through various genetic and stochastic processes. In my thesis, I investigated the impact of anthropogenic stressors on the population genetics of the zebra mussel Dreissena polymorpha. In order to analyze the genetics of zebra mussel populations, I isolated five new highly polymorphic microsatellite loci. Out of those and other already existing microsatellite markers for this species, I established a robust marker set of six microsatellite loci for D. polymorpha. rnMonitoring the biogeographical background is an important requirement when integrating population genetic measures into ecotoxicological studies. I analyzed the biogeographical background of eleven populations in a section of the River Danube (in Hungary and Croatia) and some of its tributaries, and another population in the River Rhine as genetic outgroup. Moreover, I measured abiotic water parameters at the sampling sites and analyzed if they were correlated with the genetic parameters of the populations. The genetic differentiation was basically consistent with the overall biogeographical history of the populations in the study region. However, the genetic diversity of the populations was not influenced by the geographical distance between the populations, but by the environmental factors oxygen and temperature and also by other unidentified factors. I found strong evidence that genetic adaptation of zebra mussel populations to local habitat conditions had influenced the genetic constitution of the populations. Moreover, by establishing the biogeographical baseline of molecular variance in the study area, I laid the foundation for interpreting population genetic results in ecotoxicological experiments in this region.rnIn a cooperation project with the Department of Zoology of the University of Zagreb, I elaborated an integrated approach in biomonitoring with D. polymorpha by combining the analysis techniques of microsatellite analysis, Comet assay and micronucleus test (MNT). This approach was applied in a case study on freshwater contamination by an effluent of a wastewater treatment plant (WWTP) in the River Drava (Croatia) and a complementary laboratory experiment. I assessed and compared the genetic status of two zebra mussel populations from a contaminated and a reference site. Microsatellite analysis suggested that the contaminated population had undergone a genetic bottleneck, caused by random genetic drift and selection, whereas a bottleneck was not detected in the reference population. The Comet assay did not indicate any difference in DNA damage between the two populations, but MNT revealed that the contaminated population had an increased percentage of micronuclei in hemocytes in comparison to the reference population. The laboratory experiment with mussels exposed to municipal wastewater revealed that mussels from the contaminated site had a lower percentage of tail DNA and a higher percentage of micronuclei than the reference population. These differences between populations were probably caused by an overall decreased fitness of mussels from the contaminated site due to genetic drift and by an enhanced DNA repair mechanism due to adaptation to pollution in the source habitat. Overall, the combination of the three biomarkers provided sufficient information on the impact of both treated and non-treated municipal wastewater on the genetics of zebra mussels at different levels of biological organization.rnIn my thesis, I could show that the newly established marker set of six microsatellite loci provided reliable and informative data for population genetic analyses of D. polymorpha. The adaptation of the analyzed zebra mussel populations to the local conditions of their habitat had a strong influence on their genetic constitution. We found evidence that the different genetic constitutions of two populations had influenced the outcome of our ecotoxicological experiment. Overall, the integrated approach in biomonitoring gave comprehensive information about the impact of both treated and non-treated municipal wastewater on the genetics of zebra mussels at different levels of biological organization and was well practicable in a first case study.