Das Thema dieser Arbeit ist die fuer das HEGRA Experiment entwickelte Rekonstruktions-Algoritmen, die Geometry und Energie von hochenergetischen kosmischen Gamma-Strahlen zu rekonstruieren, in die H.E.S.S. software Umgebung zu implementieren und das nicht-gepulste Energie-Spektrum des Krebsnebels zwischen Energien von 300 GeV und 20 TeV zu bestimmen. Dafuer wurden die ersten stereoskopischen Daten von Oktober und November 2003 mit einer 3 Teleskope-Konfiguration des H.E.S.S. Systems der Phase-I verwendet. Die Phase-I des H.E.S.S. Systems wurde im Dezember 2003 fertiggestellt, nachdem das vierte Teleskop in Betrieb genommen wurde. Die Rekonstruktionsalgorithmen wurden mit Monte Carlo Simulationen fuer die vollstaendige Phase-I des Teleskop-Systems getestet. Die Aufloesung fuer die rekonstruierte Richtung und Energie der einzelnen gamma-Ereignisse sind 0.15 Grad und 14 Prozent bei 45 Grad Zenitwinkel. Die Daten des Krebsnebels, die eine Wobble-Versetzung von +-0.5 Grad and +-1.0 Grad haben und die im Zenitwinkel-Bereich von 45 Grad bis 50 Grad fuer 4 Stunden beobachtet wurden, geben ein Signal von 50 Standardabweichungen. Das differentielle Energiespektrum des Krebsnebels zwischen 450 GeV und 20 TeV nach den Schnitten ist (dN / dE) = (3.37+-0.47)*10^{-11}*E^{-2.59+-0.12} cm^{-2} s^{-1} TeV^{-1}. Der integrierte Fluss oberhalb 1 TeV ist (2.11+-0.29)*10^{-11} cm^{-2} s^{-1}. Diese Resultate sind konsistent mit Messungen anderer Experimente, speziell von HEGRA und Whipple. Die Resultate stimmen mit den Erwartungen der synchroton self-Compton Modelle fuer den TeV Emissionbereich ueberein. Das magnetische Feld in der Region, wo die TeV gamma-Strahlen vermutlich entstehen, wird zu 0.18+-0.01 mG bestimmt. Die Resultate dieser Arbeit zeigen die Leistungsfaehigkeit des H.E.S.S. Teleskop-Systems. / The goal of this thesis is to implement the methods developed for the HEGRA experiment to reconstruct the geometry and energy of the air-showers induced by the cosmic high-energy gamma rays into the software environment of the H.E.S.S. experiment. Furthermore, using the implemented algorithms, a search for the unpulsed emission is aimed in the energy range between 300 GeV and 20 TeV from the Crab Nebula using the first stereoscopic data taken during October and November 2003 with the 3 telescope configuration of the H.E.S.S. array in Phase-I. The Phase-I of the H.E.S.S. array was completed in December 2003 by the addition of the fourth telescope. By testing the reconstruction algorithms of a complete Phase-I H.E.S.S. array with Monte Carlo simulations, it is found that the resolution of the reconstructed direction and energy of a gamma-ray event from a zenith angle of 45 degrees is around 0.15 degrees and 14 percent, respectively. The data on the Crab Nebula including runs with wobble offset of +-0.5 degrees and +-1.0 degrees is collected at zenith angles from 45 degrees to 50 degrees for a total of 4 hours and gives a background subtracted signal of about 50 standard deviations. The differential energy spectrum of the unpulsed gamma-ray emission from the Crab Nebula is found to be (dN / dE) = (3.37+-0.47)*10^{-11}*E^{-2.59+-0.12} cm^{-2} s^{-1} TeV^{-1} between 450 GeV and 20 TeV after all cuts. The integral flux above 1 TeV is (2.11+-0.29)*10^{-11} cm^{-2} s^{-1}. These results are consistent with the results published by other experiments, in particular HEGRA and Whipple. The results agree well with the expectation from synchrotron self-Compton models for TeV emission range. The magnetic field in the region, where TeV gamma rays are produced, is found to be 0.18+-0.01 mG. This result agrees with the magnetic field values deduced by the models. The results obtained for the Crab Nebula in this thesis demonstrate the performance of the H.E.S.S. array.

Além de sua importância ecológica para o ecossistema manguezal, o caranguejo-uçá (Ucides cordatus cordatus) é um importante recurso pesqueiro para comunidades de baixa renda do Brasil. Eventos de mortalidade em massa desta espécie têm sido registrados ao longo de vários manguezais da costa da Região Nordeste. A primeira etapa deste trabalho foi realizada de outubro/2003 a outubro/2004 e teve como objetivo estudar a dinâmica populacional do caranguejo-uçá em zonas de um manguezal do Município de Canavieiras/BA (afetado pela mortalidade em massa), comparando-o com zonas de um manguezal do Município de Caravelas/BA (não afetado pela mortalidade em massa). Após o término desta primeira etapa, a mortalidade em massa atingiu manguezais de Caravelas, iniciando-se então a segunda etapa, que teve como objetivo descrever e quantificar os efeitos deste fenômeno neste local em janeiro/2005 e julho/2005. Em Canavieiras e Caravelas, foram amostrados mensalmente 4 quadrados aleatórios de 5 X 5m em uma zona de L. racemosa (mangue branco ou manso) na margem do canal, 4 em uma zona intermediária de R. mangle (mangue vermelho) e 4 em uma zona de apicum, na transição entre o manguezal e a terra firme. Dentro dos quadrados, todas as aberturas de galerias de U. cordatus cordatus foram contadas e medidas, e um coletor de caranguejos removeu, quando possível, o caranguejo correspondente para biometria. Também foi registrada a presença de caranguejos em processo de ecdise, de fêmeas ovígeras, de galerias tapadas e galerias vazias. Adicionalmente, foram feitas estimativas da inundação dos quadrados amostrados, com base na faixa de algas nos troncos dos mangues. Através de uma regressão linear da variável menor diâmetro de abertura de galeria em função do comprimento do cefalotórax, chegou-se a uma equação de reta que permitiu a transformação de todas as medidas de galeria em medidas de comprimento de caranguejo. Foi observado que, quanto maior a inundação da zona, maior o comprimento dos caranguejos que nela habitam e que a maior freqüência de caranguejos de pequeno porte nas zonas menos x inundadas, deve-se ao fato do recrutamento ocorrer neste ambiente. Em Canavieiras, foram registrados, em campo, 113 recrutas (comprimento<0,9cm), todos dentro de galerias de outros caranguejos encontrados em áreas pouco inundadas, principalmente no limite inferior da zona de apicum. Os picos de recrutamento ocorreram de junho a outubro de 2004, indicando que os recrutas tinham cerca de 3 meses de idade. A confirmação de que o apicum funciona como um berçário para o caranguejo-uçá reforça a importância de preservação deste ambiente. A sub-população estudada em Canavieiras apresentou um aumento da densidade populacional e um deslocamento da moda para classes de comprimento maiores. Esta aparente recuperação pode estar ligada ao súbito aparecimento de caranguejos escondidos em suas galerias ou à migração de indivíduos vindos de zonas não afetadas. Canavieiras apresentou densidade populacional e comprimento médio de U. cordatus cordatus significativamente menores que Caravelas, indicando que, aparentemente, sua sub-população de caranguejos ainda não se recuperara totalmente da mortalidade em massa. Em Caravelas, registrou-se uma distribuição espacial diferenciada de machos, predominantes nas zonas mais inundadas de R. mangle, e de fêmeas, que predominaram nas zonas menos inundadas de L. racemosa, na margem do canal. Durante a ocorrência da mortalidade em massa de U. cordatus cordatus em Caravelas, observou-se que a maior parte dos caranguejos sai de suas galerias antes de morrer e que indivíduos de todos os tamanhos, nas três zonas, foram atingidos. A maior redução da densidade populacional, no entanto, foi registrada na zona de R. mangle, mais inundada, indicando que o agente causador da mortalidade em massa parece estar associado à água. Em julho/2005, seis meses após o início da mortalidade em massa, a amostragem em Caravelas registrou uma redução de 97,6% na densidade de caranguejos em tamanho comercial, valor que, extrapolado para os 11.000ha do sistema estuarino em questão, equivaleria à cerca de 45.000.000 de caranguejos mortos e um prejuízo de pelo menos R$18.000.000,00. A mortalidade em massa de U. cordatus cordatus não parece durar mais que seis meses em cada local afetado e, atualmente, está se expandindo rapidamente no sentido Norte Sul. / The mangrove crab (Ucides cordatus cordatus) is an important fishing resource for the low income communities in Brazil and also plays a role for the environment in the mangrove ecosystem. Massive mortality events of this specie have been registered in many mangrove areas in the Northeast Region of Brazil. The first step of this work was realized from October/2003 to October/2004 and had its main objective the study of the population dynamic of the mangrove crab in one particular mangrove area in Canavieiras/BA (affected by the massive mortality), compared to another mangrove area in Caravelas/BA (non-affected by the massive mortality). After the finishing of this first part of the work, the mass mortality had already reached the mangrove of Caravelas, henceforth the beginning of the second step, which the main objective was to quantify and describe the effects of this mortality in the periods of January/2005 and July/2005. In Canavieiras and Caravelas, four 5 X 5 random quadrats were monthly sampled in one L. racemosa (white mangrove) zone, in the channel bank, in one R. mangle (red mangrove) zone, in between, and in an apicum zone, in the transition for the dry land. Within the quadrats, all the apertures` burrows of U. cordatus cordatus were measured and counted. One crab gatherer removed, whenever possible, the correspondent crabs for biometry. It was also noted the presence of crabs in molting process, egg-bearing females, capped and empty burrows. Additionally, flooding of the quadrats was sampled based upon the algae height on the mangrove prop root. A simple linear regression of the aperture minimum diameter variable in function of the carapace length was done. With the obtained equation all the crab`s burrows measured were transformed in carapace length values. It was observed that the more the zone was flooded the larger size of crab was found and that smaller crabs prevailed in dryer zones in consequence of the recruitment in this habitat. In Canavieiras, 113 recruits (length<0.9cm) were registered on the field survey. All of them were found in burrows belonging to other crabs of less xii flooded areas, mainly on the inferior limit of the apicum zone. Recruitment peaks occurred from June/2004 to October/2004 indicating that the recruits had around three months age. Confirming that the apicum zone plays a role of nursery for the mangrove crab reinforces the importance of this particular environment preservation. The sub-population surveyed in Canavieiras presented an increased density and a shifting mode to higher length classes. This apparent recovery could be linked to sudden appearance of hidden crabs or migration of individuals coming from non-affected zones. Mean population density and carapace length were significantly lower in Canavieiras than in Caravelas, pointing out that apparently Canavieiras crab subpopulation didn`t recover completely from the mass mortality yet. The study in Caravelas showed a differential distribution of crabs with males predominating in flooded red mangrove zone and females preferring dryer zones of white mangrove near the channel banks. During the U. cordatus cordatus mass mortality in Caravelas most of the crabs got out of their burrows before they died. It was also proved that crabs of all sizes from the three zones were affected. Actually the greatest reduction in population density was found in the R. mangle zone, which is the most flooded, indicating that the mortality agent seems to be associated with the water. In July/2005, after 6 months from the beginning of the mass mortality, the Caravelas survey showed a 97.6% reduction of commercial sized crabs density, which means a mortality of 45.000.000 crabs within 11.000ha of mangroves, equal to at least R$18.000.000,00 loss. The mass mortality of U. cordatus cordatus seems to last not more than six months in each place, and presently it is expanding quickly on North to South direction.

O presente estudo teve como objetivo desenvolver uma nova proposta de uso de um biomonitor na identificação de fontes emissoras de metais no meio ambiente. Foi selecionada a espécie de siri Callinectes danae como biomonitor e o estuário de Santos como área de estudo. Numa primeira etapa e considerando que o siri é um organismo bentônico, foi realizada uma avaliação preliminar do teor de metais no sedimento do estuário. Em seguida, foi realizada uma avaliação preliminar do teor de metais nos diferentes tecidos de indivíduos coletados na região (brânquias, hepatopâncreas e músculos). Baseado nos experimentos anteriores, foi proposto um modelo de distribuição dos metais entre os tecidos e destes em relação aos sedimentos. A validação deste modelo de distribuição (assinatura química) foi realizada por meio de um conjunto de procedimentos que visaram testar: 1) a robustez em função do tempo; 2) a especificidade para a região de estudo; 3) a sensibilidade às alterações dos níveis de metais em cada tecido. A partir deste modelo, foram identificados indícios para atribuição de fontes emissoras de metais. Desta forma, concluiu-se que, para a região do estuário de Santos, o siri da espécie C. danae pode ser utilizado como um biomonitor. O modelo proposto foi eficaz, uma vez que foi capaz de responder de forma conclusiva-positiva a todos os testes realizados na sua validação, confirmando esta espécie como um biomonitor definitivo para região. A robustez do modelo irá aumentar com novas coletas e a realimentação do banco de dados. / This study aimed to develop a new methodology for the use of a biomonitor in the identification of metal discharges in environmental evaluations. Crabs of Callinectes danae species were used in an evaluation conducted in the Santos Estuarine System. In the first experiment and since C. danae is a benthic species, a preliminary assessment of the metal concentrations in sediment samples collected in the Santos Estuarine System was performed. Subsequently, a preliminary assessment of metal concentrations in the C. danae tissues was also peformed. The last experiment aimed to identify a chemical fingerprint for the Santos Estuarine System.The development of validation procedures for this model (chemical fingerprint) was conducted and aimed to test: 1) the stability of this model through time; 2) its local specificity for the Santos Estuarine System; 3) the sensibility of this model due to modifications in the metal concentrations in each tissue (gills, hepatopancreas and muscles). By the use of this model, it was possible to identify the sources of metal emissions. According to the results, C. danae can be used as a biomonitor for the Santos Estuarine System. The established model was able to responde in a positive-conclusive way to all the tests performed in its validation, confirming this species as a definitive biomonitor for this area. Thus, the stability of this model will increase with new sampling campaings and consequently introduction of new information in the database.

It is often hypothesised that marine species with mobile planktonic phases are capable of widespread dispersal and may therefore be genetically homogenous throughout their distribution. Studies that have demonstrated positive correlation between duration of plankton phase and levels of gene flow reinforce the prediction that life history characteristics of marine species determine the potential extent of genetic and demographic connectivity throughout their distributions. This prediction has however been challenged by studies that have employed genetic markers highly sensitive to both historical and contemporary demographic changes. Disparities between dispersal potential and measured levels of gene flow have been demonstrated both among historically disconnected ocean basins and within semi-enclosed areas of strong hydraulic connectivity. These studies and others highlight a need for greater focus on factors that may influence population structure and distribution for marine species. In this thesis, I have examined genetic structure within and among populations of an estuarine species of mud crab Scylla serrata (Forskal, 1775) using a number of genetic markers and methods. The species is widely distributed throughout mangrove and estuarine habitats of the Indo - West Pacific (IWP); it is generally assumed that life-history characteristics of S. serrata promote high levels of population admixture and gene flow throughout its distribution. Alternatively, factors that have promoted population genetic structure for a variety of IWP marine species may also have affected S. serrata populations. By investigating genetic structure at several spatial scales of sampling, I was able to address a variety of hypotheses concerning the species distribution, dispersal, and genetic structure. Episodic changes to marine habitat and conditions experienced within the IWP during the Pleistocene may have affected genetic structure for a broad variety of marine taxa. The relative strength of this hypothesis may be assayed by comparative genetic studies of widespread IWP taxa with high dispersal capacity. In order to ascertain levels of historical and contemporary gene flow for S. serrata, I investigated the phylogeographic distribution of mitochondrial DNA haplotypes sampled throughout the species range. Adults were sampled from three west Indian ocean locations (N=21), six west Pacific sites (N=68), and two sites from northern eastern Australia (N=35). Temperature gradient gel electrophoresis and sequencing of 549 base pairs of the mitochondrial cytochrome oxidase I (COI) coding gene identified 18 distinct haplotypes. Apart from that seen in northern Australia, haplotype diversity was low (h < 0.36) at each of the locations. Total nucleotide diversity in the entire sample (excluding northern Australian locations) was also low (p = 0.09). Haplotypes clustered into two clades separated by approximately 2% sequence divergence. One clade was widespread throughout the IWP (clade 1) whereas the other was strictly confined to northern Australia (clade 2). Genealogical assessment of sequenced haplotypes relative to their distributions suggested that a historical radiation of clade 1 S. serrata throughout the IWP occurred rapidly and recently (<1Myr bp) from a west Pacific origin. The evidence of fixed unique haplotypes at the majority of locations suggested that contemporary maternal gene flow between trans-oceanic sites was limited. Contrary to reports for other widespread species of IWP taxa, there was no evidence of lengthy periods of regional separation between Indian from Pacific Ocean populations. However, results may indicate a separation of northern Australian crabs from other locations before and during the IWP radiation. I speculated that this isolation might have resulted in the formation of a new species of Scylla. Additional sampling of mud crabs from the Australian coastline allowed an examination of the diversity and distribution of clade 1 and 2 haplotypes among recently formed shelf-connected coastal locations, and across a historical bio-geographic barrier. Over 300 individuals were sampled from multiple locations within coastal regions (western, northern and eastern) of Australia and analysed for mutational differences at the COI gene. Analysis of molecular variance partitioned by sampling scale (Among regions, within regions, and within all locations) indicated mitochondrial haplotypes were structured regionally (P < 0.001), which contrasted with evidence of genetic panmixia within regions. Regional genetic structure broadly correlated with hydrological circulation, supporting the contention that release and transport of propagules away from the estuary may allow genetic connectivity among widespread shelf-connected S. serrata populations. That similar patterns of maternal gene flow were absent among trans-oceanic populations may indicate that the spatial scale of effective dispersal for this species is generally limited to areas of coastal shelf. The two clades of haplotypes were geographically separated either side of the Torres Strait, a narrow sea channel connecting the northern and eastern regions of coastal Australia. This pattern of historical genetic separation was concordant with a number of other marine species across northern Australia, and might indicate a shared history of vicariance induced by eustasy. Alternatively, differences in diversity and distribution of the clades may be evidence of two independent expansions of clade 1 and 2 crab populations into Australian regions following post-glacial estuary formation. Overall, despite evidence of genetic panmixia within extensive sections of the Australian distribution, there was also evidence of significant barriers to maternal gene flow with both shallow and deep regional phylogeographic assortment of mtDNA haplotypes. The presence of these barriers indicated both historical and contemporary factors have imposed limits to effective dispersal by this species among coastal habitats. A subset of the Australian sample (8 locations, N = 188) was also examined for variation at five microsatellite loci developed specifically here for S. serrata. I examined variation among samples at each of the loci to: a) independently verify regional structure among crab populations previously detected using the mtDNA analysis; b) test for evidence of co-distributed non-interbreeding stocks of S. serrata within Australian waters by examining samples for segregation of alleles within microsatellite loci concordant with the two mtDNA clades. The frequency and distribution of alleles for each of the highly polymorphic microsatellites were homogenous at all levels of sample partitioning and contrasted sharply with the instances of both weak and strong regional phylogeographic assortment of mtDNA haplotypes. These contrasting results between different genomic markers were examined in relation to the species life history, and to differences in mutational rate and inheritance of the genetic markers. Several hypotheses may explain the disparity, however it is most likely that rampant homoplasy and high rates of mutation at the microsatellite in conjunction with large Ne at locations may be concerted to delay equilibrium between genetic drift and migration among populations at these highly polymorphic nuclear markers. There was also no evidence that alleles at microsatellite loci were co-segregated with mtDNA clades and therefore no evidence of segregated breeding between the clades of crabs. Whether or not this result was also driven by homoplasy at the microsatellites remains unknown. Recently established mud crab populations (~ 3-4 years old) observed in a number of southwest Australian estuaries are almost 1000 kilometres south of their previously recorded distribution on the Western Australian coast. Colonisation of the southwest region may have occurred either by a natural range expansion from northwest Australian mud crab populations or by means of translocation from any number of mud crab sources within the Indo - West Pacific. I used mtDNA analysis to verify the species and determine the potential source population(s) of the colonists, by comparing sampled genetic material from the southwest (N = 32) against that previously described for the genus. I also compared levels of diversity at mtDNA and two microsatellite loci between the colonist and suspected source population(s) to qualitatively determine if the southwest populations experienced reductions in genetic diversity as a result of the colonisation process. All colonist samples had S. serrata mtDNA COI sequences identical to one previously described as both prevalent and endemic to northwest Australia. High levels of genetic diversity among source and colonist populations at two microsatellite loci contrasted to the mitochondrial locus which displayed an absence of variation among colonists compared to moderately diverse source populations. I argued that the southwest was recently colonised by large numbers of S. serrata propagules derived from the northwest of Australia, possibly due to an enhanced recruitment event coinciding with the reported strengthening of the Leeuwin Current during 1999. Contrasting levels of diversity among nuclear and mitochondrial loci may be attributed to a difference in response by the two genomes to the colonisation process. I predict that such differences may be generally prevalent among plankton-dispersed species. Finally, I discuss aspects of the species distribution and biogeography obtained as a composite of the various results and ideas expressed in this thesis. I propose that S. serrata populations in the IWP may have experienced several cycles of extinction and population retraction from temperate areas followed by subsequent periods of colonisation and rapid coastal expansion in response to the effects of glacial episodes on coastal habitats in the IWP. I propose that persistence of this species as remnant populations of clade 1 and 2 crabs at equatorial locations during low sea level stands provided source populations for later expansions by the species into a variety of coastal areas throughout the IWP. Further analysis is required to determine if mtDNA clade 1 and 2 crabs are non-interbreeding species of mud crab.

Intestinal HCO3- secretion and the excretion of resultant CaCO3 precipitates have become a recognized characteristic of seawater osmoregulation in teleosts; however, this is the first report of this osmoregulatory strategy outside of teleosts and also includes evidence for its use in green turtles, Chelonia mydas. Furthermore, the effects of feeding on intestinal HCO3- secretion were newly investigated in teleosts. Intestinal base secretion via apical Cl-/HCO3- exchange was found to increase following feeding, at a magnitude sufficient to offset the "alkaline tide" commonly associated with digestion. Intestinal HCO3- secretion in marine teleosts draws HCO3- from both endogenous (via hydration of intracellular CO2) and serosal (blood) sources, of which serosal HCO3- was found to contribute a greater proportion to the elevated postprandial intestinal base secretion measured in gulf toadfish, Opsanus beta. The mechanism by which this serosal HCO3- crosses the basolateral membrane for subsequent secretion into the intestinal lumen was confirmed in toadfish to be a basolateral Na+/HCO3- co-transporter, tfNBCe1. Furthermore, the isolated intestinal tissue was found to have a high metabolic rate in both control and postprandial toadfish, with respect to that of the whole animal, and shows a considerable specific dynamic action (SDA) response to feeding. Overall, this dissertation provides evidence for the widespread use of intestinal HCO3- secretion as a strategy of marine osmoregulation across aquatic taxa, and also for its newly recognized involvement in postprandial acid-base balance.

Blue crabs are a widely distributed estuarine species with broad economic and ecological importance. Several studies have linked blue crabs to freshwater inflows, but the precise nature of this link is still uncertain, as blue crabs have a complex life cycle that utilizes both marine and estuarine environments. One potential link between blue crabs and freshwater inflows is during recruitment, when megalopae developing offshore return to estuaries before molting into juvenile crabs. Megalopae swim during the flood tide to ensure delivery into and farther up estuaries. The behaviors regulating selective tidal stream transport (STST) on the flood tide were originally studied in North Carolina in an estuary with regular freshwater inflows and a strong salinity gradient. The model of STST was re-examined in the Mission-Aransas, an estuary with episodic freshwater inflows and salinity gradients ranging from normal estuarine conditions to hypersaline during droughts. The behavioral responses of megalopae to a range of rates of salinity increase were tested, and then modeled onto rates of salinity change observed in the field to determine the theoretical ecological consequences of STST for blue crab populations in the Mission-Aransas Estuary. To validate the ecological trends predicted by the behavioral model of STST, a simple, long-term data set reflecting changes in megalopae abundance is needed. Hog’s hair collectors are a simple and widely used method of quantifying abundance of brachyuran megalopae, including blue crabs. However, the efficiency of hog’s hair collectors in sampling for megalopae is unknown. Several studies have reported poor correlations between settlement on hog’s hair collectors, transport, and abundance of megalopae in the plankton due to disparate temporal scales and potentially turbulence-driven decoupling. Each of these issues were addressed in field and flume experiments, which were used to develop a model for interpreting settlement on hog’s hair collectors in terms of transport and planktonic abundance. / text

In the presented thesis, the most advanced photon reconstruction technique of ground-based γ-ray astronomy is adapted to the H.E.S.S. 28 m telescope. The method is based on a semi-analytical model of electromagnetic particle showers in the atmosphere. The properties of cosmic γ-rays are reconstructed by comparing the camera image of the telescope with the Cherenkov emission that is expected from the shower model. To suppress the dominant background from charged cosmic rays, events are selected based on several criteria. The performance of the analysis is evaluated with simulated events. The method is then applied to two sources that are known to emit γ-rays. The first of these is the Crab Nebula, the standard candle of ground-based γ-ray astronomy. The results of this source confirm the expected performance of the reconstruction method, where the much lower energy threshold compared to H.E.S.S. I is of particular importance. A second analysis is performed on the region around the Galactic Centre. The analysis results emphasise the capabilities of the new telescope to measure γ-rays in an energy range that is interesting for both theoretical and experimental astrophysics. The presented analysis features the lowest energy threshold that has ever been reached in ground-based γ-ray astronomy, opening a new window to the precise measurement of the physical properties of time-variable sources at energies of several tens of GeV. / In der vorliegenden Dissertation wird die zur Zeit sensitivste Methode zur Photonrekonstruktion in der bodengebundenen Gammastrahlungsastronomie an das 28 m H.E.S.S. Teleskop angepasst. Die Analyse basiert auf einem semi-analytischen Modell von elektromagnetischen Teilchenschauern in der Erdatmosphäre. Die Rekonstruktion erfolgt durch den Vergleich des Bildes der Teleskopkamera mit der Tscherenkow-Emission, die mittels des Schauermodells berechnet wurde. Zur Verringerung des dominanten Untergrundes, der hauptsächlich durch Teilchen der geladenen kosmischen Strahlung hervorgerufen wird, werden Ereignisse anhand bestimmter Kriterien ausgewählt. Die Leistungsfähigkeit der Analyse wird unter Verwendung simulierter Ereignisse evaluiert. Die Methode wird anschließend auf zwei Gammastrahlungsquellen angewendet. Zuerst wird der Krebsnebel analysiert, die Standardkerze der bodengebundenen Gammastrahlungsastronomie. Die Resultate der Analyse des Krebsnebels bestätigen die bereits zuvor erwartete Leistungsfähigkeit der Rekonstruktionsmethode, wobei hier insbesondere die im Vergleich zu H.E.S.S. I stark verringerte Energieschwelle hervorzuheben ist. Als Zweites werden Beobachtungen der Region um das galaktische Zentrum ausgewertet. Die Analyseergebnisse dieser Daten unterstreichen die Fähigkeiten des neuen Teleskops zur Messung kosmischer Gammastrahlung in einem für die theoretische und experimentelle Astrophysik interessanten Energiebereich. Die vorgestellte Analyse besitzt die niedrigste Energieschwelle, die in der bodengebundenen Gammastrahlungsastronomie je erreicht wurde. Sie ermöglicht damit präzise Messungen der physikalischen Eigenschaften von zeitabhängigen Quellen im Energiebereich von 10 bis 100 GeV.

Mud crabs of the genus Scylla are widely exploited for aquaculture in the Asia- Pacific region. In the current study, a series of in vivo experiments were carried to assess the protein requirement, protein sparing effects of starch and the capacity of Scylla serrata to digest diets that contained different animal and plant-based feed meals and different levels and types of starch. Results from a protein requirement study indicated that juvenile S. serrata fed diets containing 45% or 55% protein demonstrated significantly higher growth responses than those fed the diet containing 25% protein. The subsequent study was carried out to determine if responses to dietary protein could be influenced by using purified wheat, potato, rice or corn starch to manipulate the gross energy level of fishmeal- based diets (18 or 15.5 MJ kg-1), i.e., to see if starch had a protein sparing effect in these animals. Overall, growth responses in this study appeared to be positively correlated with the level of protein in the diet with the highest growth rates achieved using diets containing 45% protein, regardless of the energy level of the diet. In addition, at a dietary protein level of 40% there was no evidence that the source of starch had any significant impact on growth performance or feed utilisation suggesting it had no protein sparing effect. By contrast, it was found that growth of juvenile S. serrata was strongly correlated with the intake of digestible dietary protein. The investigation of the capacity of sub-adult S. serrata to digest different animal and plant- based feed meals showed that apparent dry matter digestibility (ADMD) and apparent gross energy digestibility (AGED) values were not significant different for most selected feed meals (cotton seed, poultry, canola, fishmeal, soybean, and lupin meal). Apparent crude protein digestibility (ACPD) for all test feed meals were relatively high (86-96%). A subsequent study was carried out to determine if purified starch from different sources influenced the digestibility of fishmeal based diets. Overall, most diets containing starch were readily digested by mud crabs. In particular, there were no negative impacts on the digestibility of major nutrients (e.g. protein) observed following the inclusion of wheat, rice or corn starch in formulated feeds. Nevertheless, the apparent starch digestibility (ASD) of wheat starch decreased significantly as the inclusion level was increased from 15% to 60%, although there was no significant effect on ACPD values. At a 30% inclusion level, the ASD of diets containing different starches decreased in the order corn > wheat > potato = rice. Moreover, ACPD values were significantly higher for diets containing corn or rice starch than for those containing wheat or potato starch. The capacity of another species of mud crab commonly exploited for aquaculture in South East Asia, S. paramamosain, to digest the local plant-based ingredients (defatted soybean meal, rice bran, cassava and corn flour) was also conducted in Vietnam. Overall, the findings of this study showed that at a 30% inclusion level diets containing soybean meal or rice bran were well digested by mud crabs. In particular, the ACPD and AGED values for all diets containing soybean meal were not significantly different from the fishmeal based reference diet. Likewise, all digestibility values for the diet containing 30% rice bran were relatively high and not significantly different from the reference diet. By contrast, diets containing cassava flour appeared to be poorly utilised since their digestibility values for all parameters were lower than those from other testingredients. In summary, the apparent digestibility of dry matter, protein and energy was in the following order (from most to least digestible) soybean meal ~ rice bran > corn flour > cassava flour. In the next study the effects of attractants in diets (chicken meal, betaine, tuna oil and bait enhancer), temperature (26.5oC, 28.5oC and 30.5oC), sex (female and male) and size (small, medium and large) on feeding responses of S. serrata were investigated. Significant differences were observed in the behavioral responses of mud crabs to diets containing different attractants. Specifically, consumption of diets with chicken meal or betaine was significantly higher than for other treatments. With the exception of betaine, no significant difference in food consumption was observed when attractant inclusion levels were raised from 2% to 5%. Overall, small crabs consumed significantly more of the ration (as a percentage of body weight) than larger crabs. Temperature showed a significant impact on most behaviour of mud crabs, excepting continuation response and there was some evidence that females were significantly more active than males. Light intensity was considered as a main factor effect to crab response since there were extremely high percentage time of crab spent in half-shaded of the Y –maze which valued at 95.6%, 93.8 and 94.4% (corresponded to small, medium and large size respectively) in comparison to those of crabs spent in the unshaded side. Overall, the findings from these studies demonstrated that mud crabs have a high capacity to digest a range of plant based feed ingredients. In particular, soybean meal appeared to be well digested by both species of mud crabs examined. It was also shown that a range of purified starches were well digested by S. serrata although starch inclusion in diets did not appear to reduce the requirement for protein to promote growth. Subsequent attractant studies demonstrated that chicken meal and betaine produced significantly elevated feeding responses and food consumption when added to diets. Based on these results we propose that these ingredients can be utilised to increase the attractiveness and consumption of artificial mud crab feeds.

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Bruce R. Locke, Florida State University, FAMU-FSU College of Engineering, Dept. of Chemical and Biomedical Engineering. Title and description from dissertation home page (viewed Jan. 12, 2006). Document formatted into pages; contains xix, 250 pages. Includes bibliographical references.

Aeglidae Dana (1852) are anomuran crabs which occur exclusively in freshwater. The genus Aegla consists of 63 species and subspecies restricted to the southern South America. Highly sensitive molecular markers can help to elucidate some evolutionary features of the genus. Microsatellite markers are excellent molecular markers because they can reveal fine details of the genetic structure of a population. However, microsatellite isolation employs a laborious and expensive methodology. An alternative approach to the isolation procedure is the utilization of microsatellite markers previously developed for close species. The closer the phylogenetic relationship between two species, the more probable is the conservation of the loci and the successful cross-amplification. The present study aimed to test the crossamplification of microsatellite loci developed for two species of the family Aeglidae in other decapod crustaceans and to verify their potential for application in further studies on population genetics. Primers developed for microsatellite loci previously isolated from Aegla longirostri (AlCA135 and AlCA138) and Aegla uruguayana (Au05) were tested in seven species of the family Aeglidae, Aegla camargoi, Aegla leptodactyla, Aegla plana, Aegla platensis, Aegla spinipalma, Aegla violacea and Aegla sp.n., besides in Emerita brasiliensis (Anomura: Hippidae), Pachycheles laevidactylus (Anomura: Porcellanidae) and Trichodactylus panoplus (Brachyura: Trichodactylidae). DNA was extracted using traditional procedures. DNA samples were submitted to the Polymerase Chain Reaction (PCR) using the primers cited. The PCR products were electrophoresed in 6% polyacrylamide gels, at 100V for 24 hours. The gels were silver-stained and the band patterns were analyzed. The microsatellite markers could be transferred only within the genus Aegla, and the locus AlCA135 presented the greatest rate of success in cross-species transfer. Cross-amplification between families within the infra-order Anomura, as well as between the infra-order Anomura and Brachyura was not possible, indicating that these microsatellite loci are not conserved in distantly related species. Notwithstanding, the evaluated loci present potential for utilization within the family Aeglidae and new tests, using optimized PCR conditions, should improve the success rate in cross-amplification. / Aeglidae Dana (1852) são caranguejos que pertencem a Infraordem Anomura e são exclusivos de água doce. O gênero Aegla é constituído por aproximadamente 63 espécies, sendo restrito ao sul da América do Sul. O emprego de marcadores moleculares altamente sensíveis pode auxiliar no entendimento de aspectos evolutivos e da diversidade do gênero. Os microssatélites são excelentes marcadores moleculares que podem revelar detalhes da estrutura genética de uma população. Entretanto, o isolamento de microssatélites é uma técnica cara e trabalhosa. A utilização de locos de microssatélites previamente desenvolvidos para espécies próximas é uma alternativa ao isolamento. Quanto mais próxima a relação filogenética entre duas espécies, maior a probabilidade de conservação das seqüências e de amplificação cruzada utilizando primers heterólogos. O objetivo deste estudo foi testar a amplificação cruzada de locos de microssatélites desenvolvidos para duas espécies de Aeglidae em outros crustáceos e verificar o seu potencial para aplicação em estudos de genética de populações. Primers desenvolvidos para locos de microssatélite previamente isolados de Aegla longirostri (AlCA 135 e AlCA 138) e Aegla uruguayana (Au05) foram testados em outras sete espécies da família Aeglidae, Aegla camargoi, Aegla leptodactyla, Aegla plana, Aegla platensis, Aegla spinipalma, Aegla violacea, Aegla sp.n. e também em Emerita brasiliensis (Anomura: Hippidae), Pachycheles laevidactylus (Anomura: Porcellanidae) e Trichodactylus panoplus (Brachyura: Trichodactylidae). O DNA foi extraído utilizando o método tradicional de fenol-clorofórmio. As amostras de DNA foram submetidas a uma Reação em Cadeia de Polimerase (PCR) com os primers citados. Os produtos da PCR foram submetidos à eletroforese em gel de poliacrilamida 6% a 100V por 24 horas. Os géis foram corados com nitrato de prata e os padrões de banda foram analisados. Observou-se transferência dos marcadores microssatélites somente dentro do gênero Aegla, e o loco AlCA135 foi o que apresentou maior índice de sucesso na amplificação cruzada. Não foi observada amplificação cruzada entre famílias dentro da infraordem Anomura e nem entre as infraordens Anomura e Brachyura, indicando que esses locos de microssatélites não se encontram conservados em espécies distantemente relacionadas. Entretanto, os locos avaliados apresentam potencial de utilização dentro da família Aeglidae e novos testes, otimizando as condições de PCR, poderão melhorar os índices de sucesso de amplificação cruzada.