Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-08-24T20:25:23Z No. of bitstreams: 1 viniciusjosepilate.pdf: 4576162 bytes, checksum: b62d296b1537238b9c96d99b034cb665 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-25T12:05:45Z (GMT) No. of bitstreams: 1 viniciusjosepilate.pdf: 4576162 bytes, checksum: b62d296b1537238b9c96d99b034cb665 (MD5) / Made available in DSpace on 2017-08-25T12:05:45Z (GMT). No. of bitstreams: 1 viniciusjosepilate.pdf: 4576162 bytes, checksum: b62d296b1537238b9c96d99b034cb665 (MD5) Previous issue date: 2017-07-05 / Sibynomorphus neuwiedi e Sibynomorphus mikanii são serpentes de pequeno porte, conhecidas como cobras dormideiras, noturnas, não peçonhentas e malacófagas. Ambas ocorrem em áreas florestais de Mata Atlântica e ambientes alterados, porém S. mikanii ocorre mais frequentemente no Cerrado. Estudos parasitológicos, biológicos, ecológicos e morfológicos envolvendo essas espécies ainda são escassos. Os objetivos do presente estudo foram analisar a ecologia de helmintos, a dieta e a ecomorfologia das serpentes S. neuwiedi e S. mikanii de Minas Gerais, Brasil, registrar a helmintofauna de suas presas, verificar os efeitos da sazonalidade e do sexo, estado reprodutivo, tamanho e massa corporal destas serpentes, assim como do tamanho dos órgãos parasitados, sobre seus helmintos, e verificar os efeitos ecológico, filogenético e sexual na variabilidade morfométrica. As 39 serpentes analisadas de S. neuwiedi e as 49 de S. mikanii da Coleção Herpetológica da UFJF – Répteis tiveram aferidos comprimento e largura da cabeça, largura interocular, comprimentos rostro-cloacal, da cauda e total, e massa corporal. Posteriormente foram necropsiadas, sexadas e analisadas quanto à maturidade, tendo a cavidade corporal, órgãos e conteúdos digestórios analisados em busca de helmintos e presas. Órgãos parasitados foram medidos. Foram coletados 30 espécimes de moluscos da família Veronicellidae, eutanasiados, fixados, conservados e, somados aos espécimes encontrados nos estômagos das serpentes, foram dissecados e examinados para a identificação e em busca de helmintos. Os helmintos encontrados nas serpentes e nos moluscos foram lavados, fixados, conservados, quantificados, identificados e fotografados. Foi realizada a morfometria de trematódeos e nematoides. As comunidades de metazoários parasitos das serpentes foram formadas apenas por endoparasitos dos grupos dos helmintos e apresentaram riqueza e diversidade baixas, padrão de distribuição agregado, caráter isolacionista, especificidade quanto aos sítios de infecção e predominância de apenas um táxon parasitário por infracomunidade. As prevalências foram medianas. Ambas espécies de serpentes foram parasitadas por dois táxons de trematódeos, enquanto a serpente S. neuwiedi também apresentou três táxons de nematoides e S. mikanii, quatro (dois em comum entre estas serpentes). Os táxons parasitários predominantes foram Rhabdias sp. e Strongyluris sp. em ambas espécies de serpentes, e Mesocoelium sibynomorphi em S. neuwiedi, não apresentando o tamanho deste último helminto nesta serpente relação de intensidade-dependência. As serpentes apresentaram dietas semelhantes: moluscos de espécies da família Veronicellidae, sendo registradas as espécies-presas Sarasinula linguaeformis na serpente S. neuwiedi e Latipes erinaceus e Sarasinula sp. na serpente S. mikanii. Larvas de nematoides Strongyluris sp. foram os helmintos em comum entre essas serpentes e suas presas. A variação na sazonalidade, o sexo, o estado reprodutivo, o tamanho e a massa corporal de S. neuwiedi e S. mikanii, e o tamanho dos órgãos parasitados, não exerceram influência sobre as comunidades de helmintos destas serpentes. Essas espécies não apresentaram dimorfismo sexual. O habitat não influenciou a morfologia dessas serpentes, enquanto a filogenia influenciou a morfologia de fêmeas adultas, o que não ocorreu em fêmeas jovens e machos. / Sibynomorphus neuwiedi and Sibynomorphus mikanii are small sized snakes, known as sleepy snakes, nocturnal, non-venomous and snail eaters. Both occurs in Mata Atlânica forests and impacted environments, however S. mikanii is more frequently found in Cerrado. Studies about parasitology, biology, ecology and morphology of both species are scarce. The goals of the present study where to analize ecology of helminths, the diet and ecomorphology of the snakes S. neuwiedi and S. mikanii from Minas Gerais, Brazil, register the helminths presentes in their preys, verify the effects of seazonality and gender, reproductive state, size and body mass of these snakes, so as the size of parasitized organs, on their helminths, and verify the ecological, phylogenetic and sexual effects at morphometric variation. The 39 analyzed individuals of S. neuwiedi and the 49 specimens of S. mikanii from the Herpetological Collection of the UFJF – Reptiles have had measured their length and width of head, length between eyes, rostrum-cloacal length, tail and total, and body mass. Subsequently where necropsied, sexed and analyzed the maturity, the body cavity, organs and digestive contents searched in search of helminths and preys. Parasitized organs were measured. It were colected 30 specimens of snails from Veronicellidae family, euthanasia was realized and the animal fixed, conserved and, added to the specimens found in snakes stomach, these were dissected and examined to identification and pursuit of helminths. The helminths found in the snakes and in molluscs were washed, fixed, conserved, quantified, identified and photographed. It was realized morphometry of trematodes and nematodes. The metazoans parasites communities of the snakes where composed only by endoparasites from helminths group and presents low richness and diversity, distribution patttern assembled, isolacionist profile, specificity to infection sites and predominance of only one parasite taxon by infracommunity. The prevalences were average. Both species of snakes were parasitized by two taxa of trematodes, while S. neuwiedi presented also three taxa of nematodes and S. mikanii, four (two in common amongst these snakes). The prevailing parasites taxa were Rhabdias sp. and Strongyluris sp. in both species of snakes, and Mesocoelium sibynomorphi in S. neuwiedi, do not presenting the size of this last helminth in this snake relation of intensity-dependency. The snakes presented similar diet: molluscs from species of Veronicellidae family, being registered the prey-species Sarasinula linguaeformis in S. neuwiedi and Latipes erinaceus and Sarasinula sp. in S. mikanii. Larval forms from the nematode Strongyluris sp. was the common helmint between these snakes and their prey. The seazonality variation, gender, reproductive state, size and body mass of S. neuwiedi and S. mikanii, and the size of parasitized organs, did not influenced the helminth communities of these snakes. These species did not present sexual dimorphism. The habitat did not influence the morphology these snakes, while the phylogeny influenced the morphology of adult females, what did not occurred in young females and male.

Orientadores: Paulo Sérgio Moreira Carvalho de Oliveira, André Victor Lucci Freitas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T22:18:27Z (GMT). No. of bitstreams: 1 Silva_DaniloGermanoMunizda_M.pdf: 3019678 bytes, checksum: c1529979d45609cac62d29ee7dd332fe (MD5) Previous issue date: 2011 / Resumo: Em muitos ambientes tropicais, estações chuvosas se alternam com períodos de seca. A estação seca é um período de menor disponibilidade e qualidade nutricional de folhas, sendo, portanto, um período desfavorável para insetos herbívoros e gerando as oscilações sazonais em suas populações. O cerrado é um bioma neotropical sazonal, que inclui formações de savana (cerrado sensu stricto), e onde o clima se caracteriza por uma estação quente e chuvosa de outubro a abril e uma fria e seca de maio a setembro. A produção de folhas novas se concentra geralmente na estação chuvosa, tornando este um período favorável para muitos insetos herbívoros tais como as borboletas. Em seu estágio larval, as borboletas são herbívoros vorazes cujas populações comumente oscilam de acordo com a disponibilidade de folhas adequadas ao desenvolvimento dos imaturos. Borboletas podem ser divididas funcionalmente em duas guildas: as que se alimentam em sua forma adulta do néctar de flores, e aquelas que se alimentam dos líquidos oriundos de frutos em decomposição, seiva de árvores, carcaças de animais e excrementos. As espécies do segundo grupo são conhecidas como borboletas frugívoras. A guilda de borboletas frugívoras tem sido amplamente utilizada em estudos de ecologia de comunidades devido à facilidade de captura usando armadilhas com iscas de fruta fermentada, e a relativa facilidade de identificação. Entretanto, poucas vezes esta comunidade foi estudada em ambientes abertos, e raramente em trabalhos envolvendo sazonalidade. Nesta dissertação exploramos a sazonalidade das borboletas frugívoras do cerrado sensu stricto em dois capítulos. No primeiro abordamos a composição da comunidade, suas alterações ao longo do ano bem como suas oscilações de abundância. A maior abundância de borboletas ocorreu no meio da estação chuvosa, enquanto o pico de riqueza ocorreu ao final desta estação. Satyrini foi o grupo mais abundante na estação chuvosa (principalmente Yphthimoides manasses), enquanto na estação seca foi Biblidinae (principalmente Hamadryas februa). No segundo capítulo analisamos em detalhe a relação fenológica entre a borboleta Eunica bechina e sua planta hospedeira, o pequizeiro Caryocar brasiliense. Esta planta possui nectários extraflorais atrativos para formigas, que patrulham a planta e atacam as larvas de E. bechina. Observamos a maior ocorrência de larvas no início da estação seca, quando ocorreu a maior produção de folhas. Ovos e larvas estavam presentes em quase todos os meses de amostra, exceto no final da estação chuvosa. Propomos que este seja um período de inatividade reprodutiva na espécie, devido à baixa disponibilidade de folhas jovens / Abstract: In many tropical environments, rainy and dry seasons alternate. The dryer season has decreased leaf availability and the nutritional quality of leaves is also low - thus it is an unfavorable period for herbivorous insects and generates seasonal oscillations in their populations. The cerrado is a neotropical seasonal biome characterized by a hot/rainy and a cold/dry season. Leaf production is generally concentrated in the rainy season, which is the favorable period for herbivorous insects such as butterflies. In its larval stage, butterflies are voracious and specialized herbivores, and their populations commonly oscillate according to the availability of adequate leaves for immature feeding. Butterflies can be categorized in two functional guilds according to the food resources utilized by the adults: one group feeds on flower nectar, whereas another group of species feed on the liquids from rotting fruits, carcasses and excrements, and also plant sap. The latter group is known as fruit-feeding butterflies. Fruit-feeding butterfly guild has been widely used in studies of community ecology because they are easily captured using traps with fermented fruit, and also easily identified. Surprisingly, however, fruit-feeding butterflies have rarely been studied in seasonal, open environments. In this dissertation we investigated the seasonality of fruit-feeding butterflies in the cerrado sensu stricto. In the first chapter we decribe the composition of the community, changes through the year, and oscillations in its abundance. The greatest abundance occurred in the mid rainy season, while richness peaked at the late rainy season. Satyrini was the most abundant group in the rainy period (mainly Yphthimoides manasses), whereas Biblidinae (mainly Hamadryas februa) was more common in the dry season. In the second chapter we analyze in detail the phenological relationship between the butterfly Eunica bechina and its hostplant Caryocar brasiliense. The larvae feed only on the young leaves of C.brasiliense that bear extrafloral nectaries, which attract ants that patrol the plant and attack E. bechina larvae. We observed the larger occurrence of larvae in the early rainy season, when most young leaves are produced. Eggs and larvae where present at almost all sampling months, except in the late rainy season. We suggest that this is a period of reproductive inactivity in the species, due to the low availability of young leaves / Mestrado / Ecologia / Mestre em Ecologia

This study examines price formation in one of the largest wholesale electricity markets in the world: the Pennsylvania Jersey Maryland Interconnection, which serves 13 states and the District of Columbia with over 60 million consumers. The contribution of this thesis is to apply a variety of time series models offered in the literature to a large data set describing a single market, allowing for a comparison of their performance as well as demonstrating their validity. A central question that drives market deregulation is if it has created efficiency gains. To formalize this notion of efficiency, we implement tests for stationarity to measure the degree of randomness over time, finding that short run volatility can result in the outcomes for these tests that are inconclusive. We explore this volatility structure using Asymmetrical Power Autoregressive Conditional Heteroskedastic (APARCH) framework which captures the asymmetric nature of price shocks, finding that this behavior is unique to electricity returns, and that APARCH offers a better modelling alternative than simpler representations. Additionally, we account for long memory given the seasonal drivers of electricity prices which are persistent using Autoregressive Fractionally Integrated Moving Averages (ARFIMA). Temperature related market drivers are further modelled using Fourier based seasonality functions which enable us to capture cycles over multiple frequencies. Lastly, we provide an application of Markov Regime Switching models to account for the possibility of multiple states. Although appealing from a theoretical perspective, we find that the increased complexity of the model does not necessarily translate to better performance over simpler non-switching alternatives. These findings highlight the importance of establishing the features of the time series before selecting an appropriate model, and motivating it with economic rationale. / Graduate

Understanding the mechanism of photosynthetic seasonality in Amazonian evergreen forests is critical for its formulation in global climate and carbon cycle models. However, the control of the unexpected photosynthetic seasonality is highly uncertain. Here we use eddy-covariance data across a network of Amazonian research sites and a novel evapotranspiration (E) and two-leaf-photosynthesis-coupled model to investigate links between photosynthetic seasonality and climate factors on monthly scales. It reproduces the GPP seasonality (R-2=0.45-0.69) with a root-mean-square error (RMSE) of 0.67-1.25gCm(-2)d(-1) and a Bias of -0.03-1.04gCm(-2)d(-1) for four evergreen forest sites. We find that the proportion of diffuse and direct sunlight governs the photosynthetic seasonality via their interaction with sunlit and shaded leaves, supported by a proof that canopy light use efficiency (LUE) has a strong linear relationship with the fraction of diffuse sunlight for Amazonian evergreen forests. In the transition from dry season to rainy season, incident total radiation (Q) decreased while LUE and diffuse fraction increased, which produced the large seasonal increase (similar to 34%) in GPP of evergreen forests. We conclude that diffuse radiation is an important environmental driver of the photosynthetic seasonality in tropical Amazon forests yet depending on light utilization by sunlit and shaded leaves. Besides, the GPP model simulates the precipitation-dominated GPP seasonality (R-2=0.40-0.69) at pasture and savanna sites. These findings present an improved physiological method to relate light components with GPP in tropical Amazon. Plain Language Summary Understanding the mechanism of photosynthetic seasonality in Amazonian evergreen forests is critical for its formulation in global climate and carbon cycle models. However, the control of the unexpected photosynthetic seasonality is highly uncertain. Here we use eddy-covariance data across a network of Amazonian research sites and a novel evapotranspiration (E) and two-leaf-photosynthesis-coupled model to investigate links between photosynthetic seasonality and climate factors on monthly scales. It reproduces the GPP seasonality (R2= 0.45-0.69) for four evergreen forest sites. We find that the proportion of diffuse and direct sunlight governs the photosynthetic seasonality via their interaction with sunlit and shaded leaves, supported by a proof that canopy light-use efficiency (LUE) has a strong linear relationship with the fraction of diffuse sunlight for Amazonian evergreen forests. We conclude that diffuse radiation is an important environmental driver of the photosynthetic seasonality in tropical Amazon forests yet depending on light utilization by sunlit and shaded leaves. Besides, the GPP model simulates the precipitation-dominated GPP seasonality (R2= 0.40 similar to 0.69) at pasture and savanna sites. These findings present an improved physiological method to relate light components with GPP in Amazon.

Les forêts côtières inondables (FCI) des régions tropicales et subtropicales remplissent des fonctions écologiques nécessaires aux écosystèmes marins côtiers situés en aval et aux populations humaines vivant à proximité Aux Antilles, les mangroves et les forêts marécageuses à Pterocarpus officinalis sont structurés par des espèces ligneuses qui ont développé des adaptations particulières à la salinité, à l’inondation et aux substrats meubles sur lesquels elles reposent. Dans des contextes climatiques à forte saisonnalité, les saisons sèches prolongées entraînent de fortes variations de la salinité et du niveau de la nappe, que le changement climatique devrait amplifier. Les modèles climatiques de la région Caraïbe prévoient des saisons sèches plus sèches liées à une baisse des précipitations de 20 à 50 %. Or, la question des capacités de résistance et d’acclimatation des espèces ligneuses des FCI à des variations saisonnières marquées de leur environnement édaphique a été peu traitée dans la littérature scientifique.L’objectif de ce travail de thèse a été double. Il s’est agi, d'une part, de caractériser la structure et la croissance de faciès de végétation représentatifs des FCI antillaises et de mettre en évidence leurs déterminants. A cet effet, des individus adultes, des espèces ligneuses dominantes des FCI, (Avicennia germinans, Laguncularia racemosa, Pterocarpus officinalis, Rhizophora mangle), dans cinq faciès de végétation sur le gradient terre-mer, ont été suivis sur l'île de Grande-Terre (Guadeloupe). D’autre part, les effets de variations salines extrêmes sur la croissance et l’écophysiologie de ces quatre espèces ont été évalués au stade plantule par une expérience en conditions contrôlées.A travers cette étude, il a été montré que les différences de salinité et de fertilité entre les stationspermettent d’expliquer la composition et la structure des peuplements de FCI. Cette étude a égalementmontré que P. officinalis peut se maintenir dans une gamme de salinité plus large que ne l'indiquait lalittérature.Dans le contexte des Antilles où les marnages sont faibles, la saisonnalité du climat entraine des variations saisonnières importantes d’un ensemble de descripteurs édaphiques tels que le niveau de la nappe, la salinité du sol, le pH et le potentiel RedOx. L’inondation et la salinité des sols sont fortement corrélées aux variations mensuelles des précipitations. Les périodes sèches sont accompagnées de salinités élevées et d’une baisse du niveau de la nappe allant jusqu’à l’exondation des sols dans toutes les stations suivies. Les stress environnementaux liés à la saisonnalité entrainent une baisse de la production primaire. L’accroissement cambial mensuel des individus est fortement corrélé avec les précipitations et l’intensité du vent. Dans les stations de mangrove, la sècheresse édaphique régule la production primaire des palétuviers. En forêt marécageuse, la part de la sècheresse atmosphérique semble plus importante pour expliquer la production de P. officinalis. Aussi, les sècheresses édaphique et atmosphérique doivent être prises en compte toutes deux pour modéliser efficacement la croissance des peuplements des FCI.Lors de la saison sèche, le stress le plus important est le stress hydrique, lié à la diminution de la teneur en eau du sol et à l’augmentation de la salinité, qui entraine des contraintes physiologiques sur les palétuviers (ajustements stomatiques, pertes de surface foliaire et de conductivité hydraulique). Le stress ionique, lié à la toxicité des ions Na+ et Cl-, permet aussi d’expliquer une partie de la contrainte sur l’assimilation en carbone. En saison sèche, l’aération des sols ne se traduit pas par une amélioration des performances de croissance chez toutes les espèces. Aussi, la croissance cambiale maximale de toutes les espèces de FCI est réalisée en saison des pluies lorsque la salinité est faible et les niveaux d’inondation élevés. / In tropical and subtropical regions, flooded coastal forests provide essentials goods and services to local communities. In the Antilles, mangrove forests and the Pterocarpus officinalis swamp forest host tree species that are adapted to salinity, flooding and loose substrates. In areas were climatic seasonality is strong, dry seasons lead to strong fluctuations of soil salinity and water table level ; that climate change is likely to make stronger again. Climate model for the Caribbean project drier dry seasons with a decease of 20 to 50 % in annual rainfall amounts. However, resistance and acclimation ability of flooded coastal forest’s species to strong environmental fluctuations still remain poorly studied.This thesis aims two objectives. On the one hand, it aims to characterize the forest structure and monthly growth of vegetation structures representative of the Antillean flooded coastal forests and to highlight their determinants. In this respect, adult trees of the four dominant species of local flooded coastal forest (Avicennia germinans, Laguncularia racemosa, Pterocarpus officinalis, Rhizophora mangle), in five stations along a sea – land gradient were monitored on the Grande-Terre island (Guadeloupe). On the other hand, the effects of salinity variation patterns and salinity levels on growth performances and physiology of seedlings from the four same species were investigated through a greenhouse experiment.This study shows that differences among average salinity and soil fertility explain the vegetation structure of flooded coastal forest. It also extents, in the literature, the range of salinity in which P. officinalis can stand at the tree stage.In the Antilles were tidal range is small, climate seasonality lead to strong edaphic seasonal variations in water table level, soil salinity, pH and RedOx potential. Flooding and soil salinity are strongly correlated to monthly rainfall amounts: dry periods lead to high salinity and to a decrease in water table level under the soil surface. Seasonal environmental stresses lead to a decrease of primary production. Cambial growth was strongly correlated to monthly precipitation and average wind speed. In mangrove stations, edaphic drought determines primary production of mangrove trees, when, in swamp forest stations, atmospheric drought determines an important part of P. officinalis’ primary production.During the dry season, water stress is the more important environmental stress, both by the decrease in soil humidity and the increase in soil salinity, and leads to physiological strains (stomatal adjustment, loss of leaf area and hydraulic conductivity) for mangrove trees. Ionic toxicity of ions Na+ and Cl- also explains a part of the strain on carbon assimilation. During the dry season, re oxygenation of soils via low water table level does not lead to an increase of physiological traits. Thus, maximum cambial growth of all species is observed during the rainy season, when salinity is low and water table level is high.Flooded coastal forest’s species do not have the same ability to recover after a dry episode. In all the studied stations, A. germinans’ cambial growth rises back as soon as the rainy season starts, when, for one station, cambial growth of L. racemosa and R. mangle stay null during the three first month of the rainy season. This low ability to recover after a dry episode is correlated to a stronger impact of the dry season on the physiological traits of these two species.The greenhouse experiment shows that salinity variation patterns are to be taken into consideration for explaining seedlings’ growth and salinity tolerance. A stronger salinity increase impacts the growth of all the studied species; a punctual drop of salinity highlights that flooded coastal forest’s species differ in ability to take advantage of a low salinity episode. These results are coherent with field observations as cambial growth was fairly explained by monthly precipitation.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work an agricultural area in Cruz Alta/RS was used to evaluate the seasonality of CO2 concentration with respect to meteorological variables of temperature, global radiation and rainfall. The study period was January 2009 to February 2011. In this period occurred the rotation of croups: soybeans-oats- soybeans-corn. The CO2 concentration date ware obtained by an infrared gas analyzer installed in a micrometeorological tower in the center of the agricultural area. The meteorological variables were obtained form a station INMET approximately 400m of the study area. The monthly average maximum CO2 concentration occurred in May 2010, and minimum in December 2009. The month of January and June of each year were used for a detailed analysis of the relationship between atmospheric CO2 concentration ant meteorological variables. Through the daily and monthly average concentration of CO2, can be said that an annual seasonality and interanual variability exist and that it is closely linked to the regime of precipitation, air temperature and global radiation. Assessing inter-annual variability is concluded that there is an evolution of the mean CO2 concentration throughout the study period. / Neste trabalho uma área agrícola, no município de Cruz Alta/RS, foi utilizada para avaliar a sazonalidade da concentração de CO2 com relação às variáveis meteorológicas de temperatura, radiação global e precipitação. O período avaliado foi de janeiro de 2009 a fevereiro de 2011. Neste período ocorreu a rotação de culturas agrícolas: soja-aveia-soja-milho. Os dados de concentração de CO2 foram obtidos por um analisador de gás infravermelho instalado em uma torre micrometeorológica no centro da área agrícola. As variáveis meteorológicas foram obtidas de uma estação o INMET a aproximadamente 400m da área em estudo. A média mensal máxima de concentração de CO2 ocorreu em maio de 2010, e a mínima em dezembro de 2009. Os meses de janeiro e junho de todos os anos foram utilizados para uma análise detalhada da relação entre a concentração atmosférica de CO2 e as variáveis meteorológicas. Através das médias diárias e mensais da concentração de CO2, pode-se dizer que uma sazonalidade anual e uma variabilidade interanual existem e que elas estão intimamente ligadas ao regime de precipitação, temperatura do ar e radiação global. Avaliando a variabilidade interanual conclui-se que há uma evolução das médias da concentração de CO2 ao longo de todo o período estudado.

A diet study of swordfish, Xiphias gladius, was conducted in the Straits of Florida from April 2007 to December 2008. The stomachs of 131 swordfish were analyzed. Thirteen species of teleosts, three species of cephalopods, and one species of crustacean were observed in the diet. Cephalopods dominated the swordfish diet by weight (73.38%), number (69.90%), and occurrence (80.91%) and ranked highest in importance in the diet when calculating the index of relative importance (IRI). Teleosts followed by weight (25.16%), number (26.34%), occurrence (68.18%), and IRI (3,510.97). The prey species with the greatest dietary importance was Illex sp followed by unidentifiable ommastrephids. Stomach fullness index (SFI) was calculated ranging from 0 (empty stomachs) to 3.57. Additionally, correlations for juvenile male swordfish length and prey length (r²=0.647) as well as female adult swordfish weight and prey weight (r²=-0.327) were found to be significant. Overall feeding seasonality showed that swordfish primarily fed on teleosts (58%) in the spring, cephalopods (70%) in the summer, and cephalopods (75%) in the winter. When considered individually, female, male, and adult swordfish followed this pattern; however juveniles did not follow the overall feeding trend according to season. They fed regularly on cephalopods during spring (57%) and summer (61%) consuming the highest abundance of cephalopods during the winter (85%). Overall, swordfish appeared to be opportunistic feeders altering its food choices when abundance of prey may have changed or when food items were present.

Alors que l’épidémiologie de la dengue dans le sud du Vietnam est caractérisée par un régime d’hyper-endémicité, la maladie est en train d’émerger dans le nord du pays depuis une quinzaine d’années. Les incidences annuelles augmentent de façon constante d’année en année et la maladie diffuse à partir de Hanoi vers les zones rurales environnantes. Le travail de recherche effectué durant cette thèse s’intéresse aux déterminants spatiaux et temporels de la transmission de la dengue dans un contexte d’émergence. Les résultats sont organisés en 3 parties. La première se concentre sur l’étude d’une épidémie qui frappa à l’automne 2013 l’île de Cat Ba, au large du Vietnam dans la baie d’Halong. Cette île est caractérisée par une population de petite taille vivant essentiellement de l’exploitation des produits de la mer ainsi que du tourisme. Une grande proportion de cette population vit sur des villages flottant au large de l’île. Nous avons comparé l’épidémiologie de la dengue sur les villages flottants et sur l’île. Pour cela nous avons testé l’agrégation spatio-temporelle des cas de dengue. Nos résultats montrent une incidence de dengue sur les villages flottant plus forte que sur l’île, malgré des densités de moustiques plus faibles. Les cas de dengue étaient également extrêmement agrégés dans le temps et l’espace, suggérant une importation de moustiques infectés plutôt qu’un cycle de transmission local complet.La seconde partie de cette thèse s’est intéressée aux déterminants environnementaux de la transmission de la dengue dans la province de Hanoi. Cette étude est basée sur l’analyse de 31906 cas de dengue géospatialisés de 2008 à 2013 et utilise des méthodes de SIG couplées avec des techniques modernes d’apprentissage automatique dans le but de quantifier en détail les influences de chaque covariable environnementale sur le risque de dengue. Nos résultats montrent une forte influence de la densité de population sur l’incidence de la dengue, comme précédemment documenté dans d’autres régions du monde. L’incidence de la dengue augmente avec la couverture végétale pour de faibles niveaux de couverture végétale et atteint de très faibles niveaux lorsque la couverture végétale est au-dessus d’un certain seuil. Une telle relation est cohérente avec ce qui est actuellement connu sur l’écologie des vecteurs de dengue. Finalement, nos résultats ont montré une forte association entre les incidences de dengue et les zones résidentielles universitaires. Ces zones sont peuplées d’étudiants venant des régions autour de Hanoi où l’incidence est faible. La susceptibilité à la dengue de cette population estudiantine est donc plus forte que dans le reste de la population de Hanoi.La dernière partie de cette thèse s’est intéressée aux relations entre les épidémies successives de dengue à Hanoi de 2011 à 2014. L’épidémiologie de la dengue à Hanoi est très saisonnière avec de très faibles incidences en hiver. Une question majeure dans une telle situation est de savoir si les virus de dengue persistent localement entre chaque épidémie. Si non, alors les cas de dengue observés en hiver correspondraient à des cas d’importation qui pourraient démarrer une nouvelle épidémie chaque été lorsque les conditions climatiques locales deviennent à nouveau favorables pour la transmission de la dengue. Nous avons utilisé une approche de phylogénie moléculaire de virus échantillonnés à Hanoi ainsi que dans d’autres localités en Asie du sud-est d’où les virus de dengue pourraient migrer. L’idée d’une telle approche consiste à comparer les distances phylogénétiques entre des virus circulants dans une localité une année donnée et des virus circulants soit la même année dans d’autres localités, soit durant les années précédentes dans la même localité. Nos résultats suggèrent que, chaque année, les épidémies de dengue à Hanoi démarrent à partir des virus de dengue importés depuis Ho Chi Minh ville. Ce schéma semble être le cas pour les 4 sérotypes de dengue. / While high dengue transmission has been documented in the southern part of Vietnam since the late seventies, the disease started to emerge in the northern part of the country 15 years ago only. In northern Vietnam, annual incidences are consistently increasing from year to year and progressively spreading from Hanoi to the surrounding rural areas. Very little is known on the causes of this recent emergence.The research carried out in this PhD revolves around the spatial and temporal determinants of dengue epidemiological transmission in a context of emergence and the results are organized in 3 parts. The first one focuses on a single epidemic of dengue that occurred during the autumn of 2013 on the small island of Cat Ba, off the coast of Vietnam in Ha Long bay. Cat Ba island is characterized by a population of a small size mostly living from sea farming and tourism. Dengue transmission on this island has been historically rare until the major epidemics that stroke the island in 2013. The population of Cat Ba has this specificity that a large proportion of it lives of floating villages off the island coast. We were interested in investigating whether the epidemics had different behavior on the island and the floating villages. To achieve this aim, we focused on the identification of spatio-temporal clusters of cases. Our results show a higher dengue incidence on the floating villages than on the island despite lower mosquito densities. Dengue cases were also highly clustered in space and time suggesting importation of infected mosquitoes rather than a local complete transmission cycle.The second part focuses on the environmental determinants of dengue transmission in the province of Hanoi. This study is based on the use of 31,906 geospatialized cases of dengue from 2008 to 2013 and applies GIS techniques coupled with modern machine learning techniques in order to quantify in detail the influences of each environmental covariate on dengue risk. Our results showed a strong influence of population density on dengue incidence as previously reported in other parts of the world. Dengue incidence increased with tree coverage for low levels of tree coverage and then reached very low levels for tree coverage above a given threshold. This pattern is consistent with the current knowledge of the dengue vector ecology. Finally we showed a strong association of dengue incidence with academic residential areas. Such areas are populated with students coming from locations around Hanoi with low dengue incidence. The susceptibility of this student population to dengue infection is thus higher than the rest of the Hanoian population.The final part looked at the relationships between the successive epidemics in Hanoi from 2011 to 2014. Dengue epidemiology in Hanoi is very seasonal with very few cases documented in winter. A major question in such situations is whether viruses actually persist locally between epidemics. If not, then observed cases during the winter would correspond to imported cases igniting new epidemics every summer when the local climatic conditions are favorable again for local dengue transmission. To do so, we used phylogenetic analyses of virus sampled in Hanoi combined with virus sampled in other locations in Southeast Asia from where dengue viruses could migrate. The rationale behind this method is to compare the phylogenetic distances between sequences circulating in a given location in a given year and sequences circulating either the same year in other locations or previous years in the same location. Our results suggest that every year dengue epidemics in Hanoi are started from viruses imported from Ho Chi Minh city. This seems to be the case for the 4 dengue serotypes.

Doctor of Philosophy / Department of Biology / Theodore J. Morgan / Natural populations are highly complex and consist of genetically variable individuals that belong to continuously varying age classes. Genotype and age interact to determine how individuals respond to environmental stress, which ultimately determines the evolutionary trajectories and persistence of populations in variable environments. For small ectothermic species, seasonal and diurnal variation in temperature is an important source of environmental stress that impacts activity patterns and suites of phenotypes directly related to whole organism fitness. I used the genetic and ecological model Drosophila melanogaster to investigate the influence of seasonal and diurnal thermal variability on survival and reproduction in genetically diverse populations. First, I characterized changes in cold tolerance and phenotypic plasticity within a natural population as it responded to seasonal shifts in developmental and short-term acclimation and thermal selection. I found that seasonal variation in cold tolerance was significantly influenced by developmental acclimation that occurred in the field as well as in the lab, where flies that developed under warmer conditions had reduced cold tolerance relative to flies that developed under cooler conditions. Second, I characterized the effect of variation in age on stress response phenotypes in a genetically variable population. I measured genotype- and age-specific responses to multiple environmental stressors, and identified regions of the genome that were associated with age-specific stress tolerance. Genome-wide association mapping revealed that age-specific phenotypes were influenced by distinct sets of polymorphisms and genes, suggesting that the evolution of age-related decline in phenotypes is driven by mutation accumulation within phenotypes, but both mutation accumulation and antagonistic pleiotropy between phenotypes. Next, I characterized the costs and benefits of acclimation for survival and reproduction to understand how physiological and behavioral plasticity interact to determine fitness. I found that phenotypic plasticity and the capacity for acclimation significantly influenced behavioral reproductive success, but the thermal cues that led to adaptive acclimation response in survival also led to decreased reproductive success. However, genotypes with the capacity to acclimate were more likely to survive thermal variation and more likely to reproduce, suggesting that genetic capacity for phenotypic plasticity has important implications for whole organism fitness. Finally, I measured the effect of acclimation on the induction of diapause and ability to survive cold stress in the recently introduced invasive species Drosophila suzukii. D. suzukii is endemic to Asia and was first detected in California in 2008 and in Topeka, KS in 2013. Its recent invasion history thus provides an interesting model to understand the role of plasiticy in the response to a novel and variable environment. I found that diapause was induced through a plastic response to acclimation and short photoperiod, though diapause was more drastically induced by acclimation. Overall, my research provides critical insights into how organisms respond to thermal variation by intergrating quantitative genetics, ecology, evolution, and life history tradeoffs. Collectively, my research demonstrates that the ability of organisms to survive thermal stress is a function of genetic capacity to tolerate stress, genetic capacity for phenotypic plasticity, prior exposure to thermal variation, and the age of the individual.

We develop a new autoregressive conditional process to capture both the changes and the persistency of the intraday seasonal (U-shape) pattern of volatility in essay 1. Unlike other procedures, this approach allows for the intraday volatility pattern to change over time without the filtering process injecting a spurious pattern of noise into the filtered series. We show that prior deterministic filtering procedures are special cases of the autoregressive conditional filtering process presented here. Lagrange multiplier tests prove that the stochastic seasonal variance component is statistically significant. Specification tests using the correlogram and cross-spectral analyses prove the reliability of the autoregressive conditional filtering process. In essay 2 we develop a new methodology to decompose return variance in order to examine the informativeness embedded in the return series. The variance is decomposed into the information arrival component and the noise factor component. This decomposition methodology differs from previous studies in that both the informational variance and the noise variance are time-varying. Furthermore, the covariance of the informational component and the noisy component is no longer restricted to be zero. The resultant measure of price informativeness is defined as the informational variance divided by the total variance of the returns. The noisy rational expectations model predicts that uninformed traders react to price changes more than informed traders, since uninformed traders cannot distinguish between price changes caused by information arrivals and price changes caused by noise. This hypothesis is tested in essay 3 using intraday data with the intraday seasonal volatility component removed, as based on the procedure in the first essay. The resultant seasonally adjusted variance series is decomposed into components caused by unexpected information arrivals and by noise in order to examine informativeness.