The present study has attempted to investigate some of the more basic questions concerning the toxicity and accumulation of mercury in the purple shore crab, Hemigrapsus nudus. This rocky intertidal denizen is found in abundance along the entire Pacific coast of the United States from Sitka, Alaska, to the Gulf of California where it dominates the mid-tide pool region. Local specimens were collected just north of the Pacific Marine Stations, Dillon Beach, Marin County, California. The animal is hearty and can be kept in a state of good health for long periods of time in the laboratory with minimum care and negligible mortality. Most importantly, as a middle intertidal inhabitant, H. nudus would be among the first groups of organisms to feel the stress of environmental contamination from an industrial source located on the open coast. This, coupled with its wide distribution, indicates its possible use as an environmental monitor.

Depuis la moitié du XXe siècle, de nombreux chercheurs se sont penchés sur les objets et images laissés par les peuples précolombiens comme les Mochicas afin d’essayer de reconstruire ces anciennes cultures. Avec cette recherche, nous nous inscrivons dans la lignée de ces chercheurs en tentant de reconstruire le portrait de l’ontologie analogique telle que développée par les Mochicas (250-900 EC) en utilisant les représentations de crabes réalistes comme mythologiques sur le médium céramique comme sujet d’étude. Nous employons les théories de Philippe Descola, autant en ce qui concerne une définition du concept d’ontologie analogiste que pour les formes traditionnelles d’expression figurative de cette ontologie, afin d’établir une base théorique pour notre analyse. Notre étude se concentre sur un corpus de 251 céramiques que nous avons analysé pour leurs qualités formelles, iconographiques et techniques chacune de ces trois catégories nous ayant permis de mettre en lumière de riches relations ainsi qu’une panoplie d’analogies complexes. La forme des céramiques nous permet de mettre en évidence l’omniprésence visuelle de la structure analogique de l’univers mochica dans leur quotidien ainsi que les réseaux d’objets établis à travers l’espace et au coeur des différentes traditions stylistiques. L’iconographie des crabes se présente particulièrement appropriée pour cette recherche car ces êtres se situent au coeur d’un espace liminal où de nombreuses dualités se croisent. En effet, les dualismes se révèlent comme une base permettant à l’analogisme d’éclore. Les crabes sont aussi des êtres entretenant un certain nombre de relations complexes avec différents animaux et personnages mythologiques comme le Dieu à ceinture de serpents pour n’en nommer qu’un. Ainsi, les crabes occupent une place particulière au sein de la chaîne des analogies caractérisant le cosmos mochica, une chaîne qu’ils parviennent à naviguer de manière très fluide. C’est finalement avec l’étude des techniques de traitement de l’iconographie que nous parvenons à mettre en avant les analogies et relations consciemment entretenues par les potiers mochicas, ceci fait dans le but d’orienter la lecture des objets dans un sens bien précis. Ainsi, en employant ces trois catégories, nous décortiquons les différentes composantes de l’expression de l’analogisme au coeur des traditions stylistiques mochica. Avec cette recherche, nous cherchons notamment à mettre en valeur l’importance d’étudier l’art mochica de manière holiste, soit en analysant toutes les composantes de l’objet ensemble et non simplement l’image présentée dessus et ce, en lien avec différents facteurs culturels et environnementaux. / Since the mid-twentieth century, many scholars have taken a closer look at the objects and images left by pre-Columbian peoples such as the Moche in an attempt to rebuild the profiles of these ancient cultures. With this research, we follow in the footsteps of these scholars by attempting to reconstruct the portrait of the analogic ontology as developed by the Moche (250- 900 CE) using realistic as well as mythological representations of crabs on the ceramic medium as our subject of study. We use the theories of Philippe Descola, both for a definition of the concept of the analogist ontology and for the traditional forms of figurative expressions of this ontology, to establish a theoretical basis for our analysis. Our study focuses on a corpus of 251 ceramics that we have analyzed for their formal, iconographic and technical qualities, each of these three categories having allowed us to bring to light some rich relationships as well as a panoply of complex analogies. The shape of the ceramics allows us to highlight the visual omnipresence of the analogic structure of the Moche universe as well as the networks of objects established across space and different stylistic traditions. The iconography of the crabs is particularly appropriate for this research because these beings are located in the heart of a liminal space where many dualities cross. Indeed, we will see that the dualisms, particularly important within the Moche cosmovision, reveal themselves as a base allowing the analogism to bloom. The crabs are also beings that maintain a number of complex relations with different animals and mythological characters such as the Snake Belt God, to name but one. Thus, the crabs hold a particular place within the chain of analogies characterizing the Moche cosmos, a place that they manage to navigate in a very fluid way. It is finally with the study of the techniques of treatment of the iconography that we manage to highlight the analogies and relationships consciously maintained by the Moche potters, this with the aim of orienting the reading of the objects in a very precise way. Thus, using these three categories, we unravel the different components of the expression of analogism at the heart of Moche stylistic traditions. With this research, we seek to emphasize the importance of studying Moche art holistically, that is, by analyzing all the components of the object together and not just the image presented on it, in relation to various cultural and environmental factors.

Global climate change is increasing the number of hot days along the California coast as well as increasing the incidence of off-shore upwelling events that lower the pH of intertidal seawater; thus, intertidal organisms are experiencing an increase in more than one stress simultaneously. This study seeks to characterize the global protein response of the eurythermal porcelain crab Petrolisthes cinctipes to changes in thermal, pH, and tidal regime treatments, either combined or individually. The first experiment examined temperature stress alone and sought to determine the effect of chronic temperature acclimation on the acute heat shock response. We compared the proteomic response of cheliped muscle tissue following a month-long acclimation to either (1) constant 10°C, (2) daily fluctuation from 10-20°C, or (3) daily fluctuation from 10-30°C, all followed by either a 30°C acute heat shock or 10°C control. We found that ATP supply via the phosphagen system, changes in glycolytic enzymes, muscle fiber restructuring, respiratory protein fragmentation, and immunity were primarily affected by acclimation and subsequent heat shock. Acclimation to the “extreme” regimes (10°C and 10-30°C) resulted in the greatest proteomic changes, while acclimation to the moderate regime (10-20°C) resulted in a more mild response to heat shock (i.e., fewer adjustments to relative protein abundance). The second experiment sought to determine the proteomic response of gill tissue following a 17 d acclimation to daily changes in pH (ambient pH 8.1 vs low pH 7.6), tidal regime (constant immersion vs 6 h emersion), and temperature (ambient 11°C vs 22-31°C heat shock during emersion). Low pH alone reduced expression of molecular chaperones of the endoplasmic reticulum, lectins, and serine proteases involved in activating the prophenoloxidase cascade. It also increased the abundance of Na+/K+-ATPase, nitrogen metabolism enzymes, and induced changes in tubulin expression, all suggesting an increase in ammonium excretion. Addition of emersion during low pH reduced the abundance of several metabolic proteins including those involved in the proposed ammonium excretion mechanism, suggesting a decrease in metabolic function in part to prevent toxic accumulation of ammonium in the branchial chambers. Combined pH, emersion, and thermal stress increased the abundance of proteins involved in cuticle binding and crosslinking. These results indicate that the responses to pH, tidal cycle, and temperature are highly dependent on one another and that changes in ER protein maturation, ion transport, immunity, and cuticle structure are the primary biochemical systems impacted by these environmental stressors in crustacean gill.

Atlantic horseshoe crabs (Limulus polyphemus) have endured decades of intense harvest pressure. Genetics studies have shown evidence of distinct sub-groups spanning the coast, although few fine-scale studies have been done to delineate these groups on a local level. Massachusetts lies directly between two of these sub-groups. With documented differences in prosomal widths of horseshoe crabs from either side of Cape Cod, it is possible that Cape Cod is a barrier to gene flow and that there are two distinct genetic groups within Massachusetts. Regulations currently consider all horseshoe crabs to be of one stock. I examined 6 microsatellite loci from 193 horseshoe crabs collected from 7 locations across Massachusetts between 5 May and 24 June 2010. I also analyzed the prosomal widths of 324 horseshoe crabs from 8 locations across Massachusetts. Data analysis revealed low divergence with a G′ST of 0.005 (95% CI −0.004–0.013) and a G″ST of 0.015 (95% CI −0.014–0.045). Wellfleet Bay showed evidence of divergence from all other sites except Buzzards Bay. Isolation by distance is apparent via the Atlantic Ocean. Phenotypic variation in the prosomal widths of horseshoe crabs shows greater divergence among sites than neutral markers and indicates the presence of additive genetic effects. Low divergence and high heterozygosity indicate that although documented population declines have occurred, effective population size (Ne) is still large enough to maintain allele frequencies. With isolation by distance, divergence is likely to increase over time if populations remain low. Phenotypic divergence shows the possibility of local adaptation and that the implementation of management units (MUs) to the north and south of Cape Cod would be recommended as a conservative measure.

Horseshoe crabs (Limulus polyphemus) have been harvested along the east coast of the United States since the 1800s, however a Fishery Management Plan (FMP) was only recently created for this species. To date, there have not been any studies that have attempted to identify or quantify bycatch in the horseshoe crab trawl fishery. A horseshoe crab trawl survey was started in 2001 to collect data on the relative abundance, distribution, and population demographics of horseshoe crabs along the Atlantic coast of the United States. In the present study, species composition data were collected at sites sampled by the horseshoe crab trawl survey in 2005 and 2006. Seventy-six different taxa were identified as potential bycatch in the horseshoe crab trawl fishery. Non-metric multidimensional scaling (NMS) was used to cluster sites and identify the spatial distribution of taxa. Sites strongly clustered into distinct groups, suggesting that species composition changes spatially and seasonally. Species composition shifted between northern and southern sites. Location and bottom water temperature explain most of the variation in species composition. These results provide a list of species that are susceptible to this specific trawl gear and describe their distribution during fall months throughout the study area. Identifying these species and describing their distribution is a first step to understanding the ecosystem-level effects of the horseshoe crab trawl fishery. / Master of Science

Astrophysical phenomena such as self-annihilation of primordial black holes (PBHs), gamma ray bursts (GRBs), and supernovae are expected to produce single dispersed pulses detectable in the low end of the radio spectrum. Analysis of these pulses could provide valuable information about the sources, and the surrounding and intervening medium. The Eight-meter-wavelength Transient Array (ETA) is a radio telescope dedicated to the search for these pulses in an 18 MHz bandwidth centered at 38 MHz. ETA consists of 10 dual-polarized active dipoles providing an all-sky field of view. This thesis describes the results of a search campaign using ETA, namely, a Crab giant pulse (CGP) search. CGPs are already known to exist, and thus provide an excellent diagnostic for system performance. We found 11 CGP candidates in 14 hours of data. Although there has not been a single compelling detection (signal-to-noise ratio > 6), our analysis shows that at least a few of these candidates may be CGPs. We also explain the analysis preparation for PBH and GRB searches. Additionally, we describe the instrument and a software "toolchain" developed for the analysis of data that includes calibration, radio frequency interference (RFI) mitigation, and incoherent dedispersion. A dispersed pulse simulation code was developed and used to test the toolchain. Finally, improvements are suggested. / Master of Science

No description available.

I conducted a 12-month study of near-shore habitats in Lake Pontchartrain to assess spatiotemporal variation in the abundance of early life stage blue crabs (Callinectes sapidus). Collections were made using a 1 m2 throw trap and data showed that C. sapidus numbers varied over time and among sites. Two recruitment events occurred during the study. During the first recruitment in May-June, C. sapidus entered Lake Pontchartrain via the Inner Harbor Navigational Canal. In September-October, C. sapidus entered the Lake Pontchartrain via the Rigolets and Chef passes. My data suggest that C. sapidus utilize water circulation within the Lake Pontchartrain as a means of transportation throughout the estuary. MODerate-resolution Imaging Spectroradiometer (MODIS) 250 m data were analyzed to gain a large-scale view of suspended sediments patterns within Lake Pontchartrain and quantify water movement. Field sampling along with remote sensing proved to be beneficial when assessing estuarine-wide C. sapidus post-larval dispersal processes.

Die bodengebundene Gammaastronomie beschäftigt sich mit der Detektion von Photonen mit Energien >10GeV mittels der abbildenden Cherenkov-Technik. Dabei wird die Atmosphäre als Detektor verwendet: Photonen in diesem Energiebereich produzieren in ihr Teilchenschauer, die Cherenkov-Licht aussenden. Das Licht wird von Teleskopen gesammelt um Abbildungen der Schauer zu erhalten, aus denen Eigenschaften der Gammaquanten abgeleitet werden können. Da die Schauer statistischen Prozessen unterliegen, ist die Rekonstruktion der Richtung des Gammaquants durch Fluktuationen begrenzt. Die Qualität der Rekonstruktion hängt von der Energie des Quants, Beobachtungsbedingungen, Teleskop-Eigenschaften und der Rekonstruktionsmethode ab. Die Präzision der Richtungsrekonstruktion einzelner Gammaquanten wird als Winkelauflösung bezeichnet. Diese Arbeit beschäftigt sich mit der Winkelauflösung der vier Teleskope von HESS, die für bodengebundene Gammaastronomie im Energiebereich >100GeV verwendet werden. Es werden systematische Fehler der Winkelauflösungsfunktion und ihre Abhängigkeiten von Beobachtungsparametern mit Beobachtungsdaten und Simulationen abgeschätzt. Abweichungen der simulierten Auflösung von der mit HESS an Hand von Punktquellen gemessenen werden in dieser Arbeit identifiziert und quantifiziert, um mit einer korrigierten Funktion zwei Phänomene zu studieren: Erstens wird die Ausdehnung des Krebsnebels im TeV-Bereich untersucht, für die Werte bis ca. 0.03º vorausgesagt werden. Es werden die Beobachtungen des Nebels selektiert, die eine gute Auflösung und Kontrolle des systematischen Fehlers versprechen. Auf einem Konfidenzniveau von 95% wird die Obergrenze der Ausdehnung des Nebels damit zu 0.034º bestimmt. Zweitens wird nach ausgedehnter Emission um Aktive Galaxienkerne (AGN) gesucht. Verschiedene Modell-Vorhersagen werden mit den HESS-Daten dreier AGN verglichen - die so erzielten Obergrenzen auf den Fluss sind die niedrigsten bisher veröffentlichten im TeV-Bereich. / Very-high-energy (VHE) gamma-ray astronomy deals with the ground-based detection of photons with energies of tens of GeV to few 100 TeV by employing the Imaging Air Cherenkov Technique (IACT). This method uses the atmosphere as a detector for VHE gamma-rays, exploiting that photons in that energy range produce particle showers in it. The showers emit Cherenkov light, which is collected by telescopes to image single showers. Properties of the gamma-rays can be deduced from the shower images. However, the interactions in the atmosphere are statistical processes, imposing a limit on the direction reconstruction. The quality of the reconstruction depends on the energy of the primary particle, telescope properties, observational conditions and reconstruction algorithm. The precision of the direction reconstruction of single photons is called the angular resolution. In this work, the angular resolution function of the IACT experiment HESS is studied in detail. HESS consists of five telescopes, four of which were built for the energy range >100 GeV. For this sub-array, the systematic errors on the angular resolution and their dependence on observation parameters are estimated from known point sources in HESS data and Monte-Carlo simulations. A mismatch between HESS data and simulations is quantified and corrected to assess two phenomena: First, the size of the the Crab Nebula at VHE is investigated. Some models predict a size of the emission region of more than 0.03º. Including a detailed accounting of the systematic errors, an upper limit on the size of emission region of the nebula is given by 0.034º at a 95% confidence level. Second, extended emission around Active Galactiv Nuclei is searched for. Various models are probed with HESS data and the most constraining upper limits on the so-called pair halo scenario are found. Assuming a different model, extra-galactic magnetic field strengths in the range of (0.1 - 10)* 10^{-15} G are excluded at a 99% confidence level.

Orientador: Luciana Cavalcanti Maia Santos / Resumo: A pesca do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763), é uma das atividades extrativas mais antigas no Brasil, sendo caracterizada como uma das mais importantes pescarias dentro do setor artesanal em áreas de manguezal. Contudo, os altos níveis de exploração dessa espécie, associados à degradação dos manguezais, técnicas de captura não-sustentáveis e doenças, fizeram com que U. cordatus fosse incluído em 2004 na lista brasileira de espécies sobreexplotadas ou ameaçadas de sobreexplotação. Entretanto, desde 2015 o Governo do Estado de São Paulo controla a quantidade de profissionais que atuam na atividade de coleta do caranguejo-uçá, permitindo a Autorização Especial para um determinado número de pescadores residentes em toda abrangência da APA de Cananéia-Iguape-Peruíbe. A cidade de Cananéia (litoral sudeste do Brasil), tem um alto volume registrado de capturas do caranguejo-uçá a nível estadual, mas há poucos estudos sócio-ecológicos e aplicação de medidas participativas para o manejo sustentável desse recurso nesta região. Neste contexto, o presente projeto tem como objetivo analisar a pesca do caranguejo-uçá no Município de Cananéia, com foco na avaliação sócio-ecológica do conhecimento local, percepções e práticas dos pescadores, assim como na aplicação desse conhecimento ao manejo e uso sustentável deste recurso. Para tanto, foram aplicadas entrevistas junto aos pescadores locais, bem como utilizada o método de mapeamento participativo. Foi evidenciada a íntima dep... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Abstract: The crab Ucides cordatus (Linnaeus, 1763) is the older estuarine extractive activities in Brazil, and characterized as one of the most important fisheries within the artisanal sector of the mangrove areas. However, higher exploration levels of this species, associated with mangrove degradation, unsustainable techniques of capture and diseases, have included this species as overexploited or overexploitation threatened in Brazilian Redlist at 2004. However, since 2015 the government of São Paulo state controlled the number of artisanal fishermen in catching activity of U. cordatus, allowing a special authorization for a reduced number of local fishermen in that Área de Proteção Ambiental Cananeia-Iguape-Peruíbe (APA-CIP). The Cananéia city (southeast coast of Brazil) has the largest catch of crabs in the São Paulo state, but there are few social-ecological studies and participatory methods to sustainable manage of this resource in that region. In this context, the present project aims to analyze the fishing of the Ucides cordatus crab in Cananéia city, with a social-ecological (SES) analysis based on the local fishing knowledge, perceptions and practices for the fishermen, as well as in this knowledge application to management and sustainable use. Were conduzed interviews with local fishermen, and used the participatory mapping method. An intimate dependence was verified among fishermen and mangrove, where U. cordatus is a very important source of income for many fami... (Complete abstract click electronic access below) / Mestre