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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Hodnocení vlivů na životní prostředí - případová studie. Monitoring populační dynamiky lýkožroutů v plošných polomech po orkánu Kyrill. / Evaluation of the effects on the environment - a case study. The monitoring of bark-beetle population dynamics in the areal windbreak after Hurricane Kyrill.

VOJÍŘ, Lukáš January 2009 (has links)
My thesis deals with bark beetle in two model areas affected by disturbances in the Šumava Mountains which were caused by Hurricane Kyrill in January 2007. The localities are Černá hora and Kalamitní svážnice pod Trojmeznou. Monitoring on both of these localities was realized in a zone with no human intervention. On these two model areas population dynamics of bark beetle in areal blowdowns and spatial distribution of advance growth in the harmed area was determined. Based on the monitoring of individual localilities, we can presume population dynamics of bark beetle in the following years.
202

Population Ecology and Stoichiometry of the Western Black Widow Spider: From Solitary Desert Predator to Urban Pest.

January 2012 (has links)
abstract: Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC. / Dissertation/Thesis / M.S. Biology 2012
203

Population Dynamics of the Little Gulper Shark <i>(Centrophorus uyato)</i> and Community Analyses of Elasmobranch Species in the Northern Gulf of Mexico

Hipes, Jacquelin Joye 01 January 2015 (has links)
In chapter 1 I describe the population dynamics of an understudied species of gulper shark, Centrophorus uyato (common name, the Little Gulper), found in the Northern Gulf of Mexico. Sharks in the family Centrophoridae are mid-sized, demersal fish, with seven species identified in North American waters. These deepwater species can be difficult to study due to the extreme depths at which they occur. During four longlining cruises from 2012-2014, 593 sharks were landed, predominantly in the Mississippi Canyon off the Louisiana coast. Mean depth of capture was 290 m. Supplementing these data are catch records for C. uyato from a second series of cruises east of these stations. These data suggest the Little Gulper displays sexual dimorphism in its population size structure, similar to other elasmobranchs. Length frequency distributions, sex ratios by length, and length-weight curves were similar for both catch series, however females comprised a greater fraction of the catch from Mississippi Canyon stations compared to those further east. The high incidence of females in the region may indicate the use of Mississippi Canyon as a nursery for C. uyato, and the species' tendency to sexually segregate at some point in its life history. A high number of large, pregnant females, along with observations of recently delivered animals, was noted at the Mississippi Canyon sites. Little Gulper sex ratios by length exhibited a characteristic "notch", indicative of a low female-to-male ratio at intermediate lengths, then a reversal to female dominance at the largest sizes captured. I modeled this curve under various assumptions of growth, mortality, and longevity for the species. The combination of the von Bertalanffy growth parameter, K, and the total instantaneous mortality rate, Z, that best fit the data suggests a population of slow growing, long-lived animals with a differentially higher growth rate for males. In chapter 2, I examine species associations among elasmobranchs in the Northern Gulf of Mexico in relation to depth of capture. From 2011-2014, 3609 sharks, comprising 31 species in 10 families, were landed on five long-lining cruises throughout the Northern Gulf and along the West Florida Shelf. Stations were grouped a priori according to depth into one of three categories, based on pre-existing divisions in the station data: 0-73 m (shallow), 110-146 m (intermediate), and 183 m or greater (deep). Using a non-parametric multivariate analysis of variance (NP-MANOVA) and a pairwise test found I found significant differences in species composition among all three depth groupings. Gulf Smoothhound (Mustelus sinusmexicanus) and Atlantic Sharpnose (Rhizoprionodon terraenovae) contributed most to the differences, and also accounted for over 65% of the total catch. A canonical analysis of principal coordinates (CAP) showed mid-water species such as the Scalloped Hammerhead (Sphyrna lewini) to be more indicative of intermediate depth stations, while the Little Gulper (Centrophorus uyato) and Shortspine Dogfish (Squalus mitsukurii) distinguished deepwater sites. A "leave-one-out cross-validation" (LOO-CV) procedure correctly re-classified 78% of the samples back into their a priori groupings; catches from the shallow and deep groups were never confused for one another, although there was moderate confusion with classifying catches from intermediate stations. Taking into consideration the potentially large movements undertaken by many shark species on both small and large time scales, as well as additional biological and physical drivers for range and location, it is unsurprising that these animals would be present in two or more depth groups, and thus more frequently misclassified. I also performed a second analysis grouping the stations according to their location on the West Florida Shelf, or in the eastern or western quadrants of the Northern Gulf of Mexico. Again I found significant differences among the species composition of all three station groups, but the LOO-CV overall reclassification success rate was lower than when the stations were grouped according to depth. There was also a smaller interval between this reclassification success rate and one performed using random group allocation. Both of these chapters provide data on previously poorly understood species and phenomena in the Northern Gulf of Mexico. These data are important in defining the potential susceptibility of shark species and communities to future threats, including by-catch in fisheries and contamination events such as shallow and deepwater oil spills.
204

Caracterização espectroscópica da dinâmica eletrônica em moléculas de porfirina / Spectroscopic characterization of electronic dynamic in porphyrin molecule

Tiago Gualberto Bezerra de Souza 19 March 2015 (has links)
Neste trabalho descreve-se técnicas experimentais envolvendo espectroscopias ópticas lineares e não-lineares capazes de caracterizar efeitos de estados excitado singleto e tripleto em moléculas orgânicas fluorescentes. Efeitos como a absorção de estado excitado e a troca de paridade eletrônica singleto-tripleto, tem ampla aplicação em diversas áreas de interesse humano. Logo, se faz necessário o estudo e desenvolvimento de materiais com essas características, tanto quanto o aprimoramento dos métodos de caracterização dessas propriedades. Este trabalho também consta com o estudo das propriedades espectroscópicas de moléculas de porfirinina, as quais estão entre as principais moléculas utilizadas nas aplicações. Assim, submeteu-se um conjunto composto por vinte e uma moléculas, todas derivadas da molécula de porfirina e com quatro radicais acoplados a ela, às seguintes técnicas experimentais: Varredura-Z absortiva e variações dessa técnica, desenvolvidas no grupo de Fotônica-IFSC, como a Varredura-Z por Trem de Pulsos (ZTP) e a medida da Fluorescência por Trem de Pulsos (FTP), afim de caracterizar os parâmetros espectroscópicos de cada amostra correspondentes ao modelo de Jablonski com cinco níveis de energia. A caracterização desse conjunto de porfirinas permitiu a avaliação da mudança na dinâmica populacional eletrônica causada por determinados radicais, que podem favorecer um determinado efeitos e, assim, otimizar uma molécula a uma dada finalidade. / This work describes experimental techniques in linear and nonlinear optical spectroscopy able to characterize excited state singlet and triplet optical effects of fluorescent organic molecules. Effects like excited state absorption and intersystem crossing between singlet and triplet states have a broad application in several areas of human interest. So, it is useful the study and development of materials with those properties, as much as the characterization methods of them. It is also included in this work the study of the spectroscopic properties of porphyrin molecules, which are among the most used in the applications. Thus, a set of twenty one porphyrin based molecules were probed with the follow spectroscopic techniques: Absorptive Z-SCAN and variations of that technique developed in the IFSC-Photonics\' Group as Pulse Train Z-SCAN and Fluorescence by Pulse Train, in order of characterize the spectroscopic parameters corresponding to a five energy level Jablonski diagram. The characterization of the whole set of porphyrins allowed a study of the change in electronic population dynamics in the porphyrin molecule caused by a specific radical, which may privilege a certain kind of effect and, consequently, manufacturing a molecule for a given application.
205

A dinâmica espacial de engenheiros de ecossistemas / The spatial dynamics of ecosystem engineers

Caroline Franco 08 February 2018 (has links)
Engenharia de ecossistemas refere-se à habilidade de certos organismos de modificar ativamente o ambiente que os cerca. No contexto ecológico, engenheiros de ecossistemas são espécies-chave que modificam ou criam habitats por meios mecânicos ou usando suas próprias estruturas corporais. Ao criarem novos nichos, castores, recifes de corais e sociedades humanas primitivas garantem tanto a própria existência, quanto a de outros organismos no mesmo ecossistema. Devido a seu caráter de longa duração, algumas destas modificações podem persistir até mais do que a duração de uma população de engenheiros, implicando em consequências evolutivas. O estudo teórico de tal fenômeno ecológico é relativamente recente se comparado com a descrição de interações tipo predador-presa ou de competição. Apenas em 1996 Gurney & Lawton introduziram um modelo descrevendo a dinâmica populacional de engenheiros de ecossistemas, mas a partir de lá poucas modificações apareceram. Aqui nós complementamos tal modelo ao permitir que engenheiros se movam difusivamente através dos sítios de um mapa acoplado, uma formulação discreta no espaço e no tempo. A análise de estabilidade local revela a existência dos regimes estável, cíclico e caótico, com uma cascata de bifurcações levando a órbitas caóticas. Obtemos que apenas para altas taxas de crescimento, onde ocorre comportamento caótico, a dispersão influencia na dinâmica das metapopulações. Neste regime, o caos é suprimido e a extinção pode ser evitada. / Ecosystem engineering refers to the ability of certain organisms to actively modify their surrounding environment. In an ecological context, ecosystem engineers are keystone species that modify or create habitats via mechanical means or by using their own physical structures. By creating new niches, beavers, coral reefs and primitive human societies would guarantee both their and other species survival in a shared ecosystem. Due to its long-lasting character, some of this changes might outlive the engineers populations, leading to evolutionary consequences. The theoretical study of such ecological phenomena is relatively recent when compared to the description of predator-prey or competition interactions. Only in 1996 Gurney & Lawton introduced a model to describe the population dynamics of ecosystem engineers, yet since then few modifications appeared. Here we build on this model by allowing the engineers to move diffusively through the patches of a coupled map lattice, a framework discrete both in time and space. The local stability analysis reveals the existence of stable, cyclic and chaotic regimes, with period-doubling bifurcations leading to chaotic orbits. We find that only for large intrinsic growth rates, where chaotic behavior occurs, dispersal influences the metapopulation dynamics. In this regime, chaos is suppressed and extinction can be avoided.
206

"Tolerância de espécies de capim-colchão (Digitaria spp) a herbicidas na cultura de cana-de-açucar" / Tolerance of the crabgrass species (Digitaria spp) to herbicides in the sugarcane crop

Nivea Maria Piccolomini Dias 26 November 2004 (has links)
É conhecido que a utilização repetitiva e consecutiva dos mesmos herbicidas, ou de herbicidas diferentes, porém com mesmo mecanismo de ação, exerce uma pressão de seleção sobre as populações de plantas daninhas controladas. As duas formas principais de resposta das populações de plantas daninhas resultantes da pressão de seleção dos herbicidas são a mudança da flora pela seleção de espécies de plantas daninhas tolerantes, ou a seleção de biótipos de plantas daninhas resistentes aos herbicidas. Na prática têm sido observadas, pelos produtores de cana-de-açúcar, mudanças de flora pela seleção de algumas espécies de capim-colchão (Digitaria spp), as quais não têm sido controladas eficientemente pelos herbicidas normalmente recomendados para o seu controle. Suspeita-se que estas populações selecionadas são constituídas por diferentes espécies de capim-colchão, que apresentam níveis maiores de tolerância aos herbicidas. Sendo assim, os objetivos desta pesquisa foram: (i) identificar taxonomicamente as espécies de capim-colchão infestante da cultura da cana-de-açúcar no Estado de São Paulo, e avaliar a eficácia de herbicidas no controle de Digitaria nuda a nível de campo; (ii) comparar a suscetibilidade das espécies D. nuda e D. ciliaris aos herbicidas do grupo químico das triazinas, uréias substituídas, imidazolinonas, triazinonas e aos herbicidas, cujo mecanismo de ação é a inibição da síntese de caroteno, e quantificar o nível de tolerância das espécies através da elaboração de curvas de dose-resposta; (iii) determinar, com a utilização de 14C-herbicida, a absorção e translocação pelas espécies Digitaria nuda e Digitaria ciliaris dos herbicidas diuron (via folha) e imazapyr e metribuzin (via raiz). A identificação das espécies de capim-colchão (Digitaria spp) foi efetuada seguindo chave de identificação existente na literatura. No estudo da eficácia de herbicidas no controle de Digitaria nuda a nível de campo, foram utilizados oito tratamentos herbicidas, aplicados em condições de pré-emergência. As avaliações de controle foram realizadas aos 15, 30 e 60 dias após a aplicação (DAA). O estudo da eficácia de herbicidas no controle das espécies Digitaria nuda e Digitaria ciliaris, foram conduzidos em casa-de-vegetação. Foram utilizados oito tratamentos herbicidas, aplicados em condições de pré-emergência. As avaliações de controle foram realizadas aos 14 e 21 (DAA). O estudo do nível de tolerância foi realizado em casa-de-vegetação do Departamento de Produção Vegetal da ESALQ/USP, Piracicaba/SP, através de curvas de dose-resposta. Os estudos de absorção e translocação foram conduzidos em câmara de crescimento, e as análises realizadas no Laboratório de Ecotoxicologia do Centro de Energia Nuclear na Agricultura (CENA/USP), em Piracicaba, SP, utilizando-se 14C-herbicida, medindo-se a radioatividade em diferentes partes das plantas. Os resultados permitiram concluir que: (i) a espécie Digitaria nuda foi selecionada pela aplicação repetitiva dos herbicidas utilizados no controle de capim-colchão na cultura da cana-de-açúcar; demonstrando ser mais tolerante aos herbicidas dos grupos químicos das imidazolinonas e uréias substituídas, quando comparada à Digitaria ciliaris; (ii) a partir das curvas de dose-resposta, pode ser verificado que a Digitaria nuda demonstrou ser mais tolerante que a Digitaria ciliaris aos herbicidas diuron, imazapyr e tebuthiuron; (iii) a absorção e translocação não foram os mecanismos responsáveis pela tolerância apresentada pela Digitaria nuda aos herbicidas diuron e imazapyr. / It is known that the repetitive and successive use of the same or differents herbicides, but with same mechanism of action, impose a selection pressure on the weed population controled. The two main forms of weed population response resulted from the selection pressure of the herbicide is, weed species shifts, through selection of the tolerant species of weed, or selection of resistant biotipes within the population. It has been observed by sugarcane growers weed species shifts whitin the genus (Digitaria spp). It is suspected that the populations selected are constituted by different crabgrass species, with higher level of herbicide tolerance. The objectives of the research were: (i) identify taxonomically the crabgrass infesting the sugarcane crop in São Paulo state – Brazil, and to study herbicide efficacy in the control of the Digitaria nuda in field conditions; (ii) compare the susceptibility of D. nuda and D. ciliaris to herbicides of the chemical groups triazine, substituted urea, imidazolinone, triazinone, and inhibitors of carotene synthesis, and quantify the level of susceptibility of the species, through dose-response curves; (iii) determine, by using 14C-herbicide, the absorption and translocation by the species Digitaria nuda and Digitaria ciliaris of herbicides diuron (by leaf), and imazapyr and metribuzin (by root). The identification of the crabgrass species (Digitaria spp) was carry out following a identification key published in the literature. In the study of herbicides efficacy in the control of Digitaria nuda in field conditions, eight herbicide treatments, applied in pre-emergence were used, and the control percentage was evaluated at 15, 30 and 60 days after herbicide application (DAA). The study of herbicide efficacy to control the species Digitaria nuda and Digitaria ciliaris were conducted in greenhouse. Eight herbicide treatments, applied in pre-emergence were used, and the control percentage was evaluated at 14 and 21 days after herbicide application (DAA). The study of the level of tolerance was conducted in the greenhouse of the Department of Crop Science, University of São Paulo, Piracicaba/SP – Brazil, through dose-response curves; The study of absorption and translocation were conducted in a growth chamber, and the 14C-herbicide analysis was done in the Laboratory of Ecotoxicology of the Center of Nuclear Energy Applied to Agriculture, Piracicaba/SP, Brazil, using 14C-herbicide, measuring radioactivity in different plant parts. The results allowed to conclud that: (i) the specie Digitaria nuda was selected by repetitive applications of the herbicides used in the control of the crabgrass in the sugarcane crop, showing that the specie is more tolerant to the herbicides of the chemical group of imidazolinone and substituted urea, when compared to Digitaria ciliaris; (ii) From the dose-response curves study, it was observed that Digitaria nuda showed more tolerance than Digitaria ciliaris to the herbicides diuron, imazapyr and tebuthiuron; (iii) The absorption and translocation were not the mechanism responsible for the tolerance showed by Digitaria nuda to the herbicides diuron and imazapyr.
207

Padrões espaciais de abundância e dinâmica populacional em longo prazo do camarão sete-barbas Xiphopenaeus kroyeri (Heller, 1862) na Enseada de Ubatuba, SP / Long-term pattern of spatial abundance and population dynamics of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) in Ubatuba Bay, São Paulo State, Brazil

Gisele Salgado Heckler 29 August 2014 (has links)
A análise de uma população em longo prazo permite a identificação da ausência ou presença de variações nos padrões de ciclo de vida, de distribuição espaço-temporal e dinâmica populacional. O ciclo de vida do camarão sete-barbas Xiphopenaeus kroyeri foi investigado na Enseada de Ubatuba, litoral norte do Estado de São Paulo (23º25\' - 23º27\'S / 45º00\' - 45º03\' W) ao longo de um intervalo de treze anos. Amostras de material biológico, de água de fundo e de sedimento foram coletadas em quatro pontos de amostragem em três períodos de 12 meses cada: janeiro a dezembro de 1998, julho de 2006 a junho de 2007 e setembro de 2010 a agosto de 2011. Dados obtidos em 1999 foram incluídos para as análises de crescimento individual, de longevidade e de idade de maturação. Altas abundâncias de fêmeas maduras e de jovens foram respectivamente associadas a valores de temperatura da água de fundo acima e abaixo da média da região. Indivíduos adultos predominaram em pontos com variação temporal da composição granulométrica do sedimento enquanto que os jovens se estabeleceram naqueles em que o sedimento permaneceu fino entre os períodos. Em 1998, a abundância de jovens, o peso individual de machos e fêmeas de todas as categorias demográficas, a idade de maturação morfológica e fisiológica e a longevidade foram maiores do que nos outros períodos. Os parâmetros da função de crescimento de machos e fêmeas variaram entre os períodos, sem apresentarem uma tendência temporal clara. Os padrões anuais de reprodução e recrutamento foram bastante semelhantes entre os períodos. As alterações nos fatores ambientais provocadas por variações na dinâmica de massas de água, pela ocorrência de El Niño e alterações na intensidade de pesca foram consideradas como possíveis agentes relacionadas às variações nos padrões do ciclo de vida da espécie na região / Long-term studies on a population provide detection of the presence or absence of interannual variation in patterns of its life cycle, spatio-temporal distribution, and dynamics. This study investigate the population of the seabob shrimp Xiphopenaeus kroyeri within a period of 13 years in Ubatuba Bay, northern coast of São Paulo state, Brazil (23º25\' - 23º27\'S / 45º00\' - 45º03\' W). Shrimp, bottom water and sediment samples were collected from four sampling sites during three 12-month periods: January-December 1998, July 2006-June 2007, and September 2010-August 2011. Monthly data collected in 1999 were included in growth, longevity and maturation age analyses. High abundance of mature females and juveniles were associated to the occurrence of temperature values below and above the region average, respectively. Adults predominated in sites that showed temporal variation of sediment texture while juveniles occurred in sites where sediment remained fine between the study periods. In the 1998 period values of juveniles were more abundant, individual weight of all demographic categories was higher, both morphological and physiological maturity was attained later and lifespan was longer than on the following periods. Growth function parameters of males and females varied between periods with no clear temporal trend. Monthly patterns of reproduction and recruitment were similar between the study periods. Changes in the environmental conditions caused by variations in the dynamics of the local water masses, occurrence of El Niño and fishery intensity were considered as possible factors related to the interannual variations in the life cycle pattern of X. kroyeri in the study region
208

Análise computacional da disseminação de epidemias considerando a diluição e a mobilidade dos agentes / Analysis of epidemic dissemination considering dilution and mobility of the agents

Cruz, Vicente Silva January 2013 (has links)
Pesquisas sobre a propagação de epidemias são uma constante devido a sua relevância para a contenção de doenças. Porém, devido aos diversos tipos de doenças existentes, a observação de um comportamento genérico e aproximado torna-se impraticável. Neste âmbito, a elaboração de modelos matemáticos epidêmicos auxiliam no fornecimento de informações que podem ser usadas por orgãos públicos para o combate de surtos epidêmicos reais. Em paralelo, por causa do grande volume de dados que são processados na execução da simulação desses modelos, o constante aumento dos recursos computacionais desenvolvidos vem em auxílio desta tarefa. O objetivo desta dissertação é estudar o comportamento da disseminação de uma epidemia simulada computacionalmente através do modelo epidêmico SIR em reticulados quadrados considerando duas propriedades: a existência de vértices vazios e a movimentação aleatória dos agentes. Essas propriedades são conhecidas por taxas de diluição e mobilidade, respectivamente. Para alcançar esse objetivo, algumas técnicas físico-estatística, tais como a análise das transições de fase e fenômenos críticos, foram aplicadas. Através destas técnicas, é possível observar a passagem do sistema da fase em que ocorre um surto epidêmico para a fase em que a epidemia é contida, bem como estudar a dinâmica do modelo quando ele está na criticidade, ou seja, no ponto de mudança de fase, conhecido por ponto crítico. Foi constatado que a taxa de diluição influencia a disseminação das epidemias porque desloca a transição de fase negativamente, reduzindo o valor crítico da imunização. Por sua vez, a taxa da movimentação dos agentes favorece o espalhamento da doença, pois a transição de fase é positivamente deslocada e seu ponto crítico, aumentado. Além disso foi observado que, apesar desse incremento, ele não é completamente restaurado devido às restrições de mobilidade dos agentes e ao alto grau de desconectividade da rede causado pelas altas taxas de diluição. Neste trabalho nós mostramos as razões deste comportamento. / Research on the spreading of epidemics are frequent because of their relevance for the containment of diseases. However, due to the variety of existing illnesses, the observation of an approximated generic behavior becomes impractical. In this context, the development of mathematical models of epidemics assists in providing information that can be used to make strategic decisions for the combat of real epidemic outbreaks. In parallel, because of the large volume of data which has to be processed in the simulation of these models, the increase of computational performance helps with this task. The objective of this thesis is to study the behavior of the spreading of an epidemic, by computationally simulating an SIR epidemic model on square lattices, considering two properties: the existence of empty vertices and random movement of agents. These properties are known as dilution rate and mobility rate, respectively. To achieve this goal, techniques of statistical physics, such as the analysis of phase transition and power laws, were applied. With these techniques, it is possible to observe the transition of the system from the phase in which an outbreak occurs to the phase where the epidemic is contained. Additionally, we studied the dynamics of the model when it is in criticality, that is, at the point of phase transition, known as the critical point. It was found that a higher dilution rate reduces the spreading of epidemics because it shifts the phase transition negatively, reducing the value of its critical point. On the other hand, increasing the rate of movement of the agents favors the spreading of the disease, because the phase transition is shifted positively and its critical point is increased. It was noticed that, despite of this increasing, this point is not completely restored due to restricted mobility of agents and the high degree of the network disconectivity caused by the high dilution rates. In this work we show the reasons for this behavior.
209

Ageing, maturation and seasonal growth of the Argentine short-finned squid lIlex argentinus (Cephalopoda: Ommastrephidae) commercially fished in southern Brazil

Baiany, Mara Cristiane Rodrigues Silveira January 2011 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-12-15T18:25:27Z No. of bitstreams: 1 Mara Cristiane Rodrigues Silveira Bainy.pdf: 379108 bytes, checksum: 9a142cb9bf485b2d537dd0c3aef7ae9b (MD5) / Approved for entry into archive by Sabrina Andrade (sabrinabeatriz@ibest.com.br) on 2013-12-18T18:00:36Z (GMT) No. of bitstreams: 1 Mara Cristiane Rodrigues Silveira Bainy.pdf: 379108 bytes, checksum: 9a142cb9bf485b2d537dd0c3aef7ae9b (MD5) / Made available in DSpace on 2013-12-18T18:00:36Z (GMT). No. of bitstreams: 1 Mara Cristiane Rodrigues Silveira Bainy.pdf: 379108 bytes, checksum: 9a142cb9bf485b2d537dd0c3aef7ae9b (MD5) Previous issue date: 2011 / Exemplares de Illex argentinus capturados pela pesca comercial ao longo do sul do Brasil foram amostrados mensalmente de Março de 2007 a Janeiro de 2008, para comprimento dorsal do manto (ML), sexo, idade e maturidade e para comparação entre ‘estação fria’ (Junho-Novembro) e ‘estação quente’ (Dezembro-Maio). Os machos foram 51.5% da amostra, 106-330 mm, 96-275 dias; enquanto que as fêmeas foram 48.5%, 114-341 mm, 124-257 dias. A distribuição de freqüência de ML mostrou que exemplares pequenos ocorreram durante todo o ano enquanto que os machos e a fêmeas grandes ocorreram apenas na ‘estação fria’. O retro-cálculo da data de eclosão mostrou uma desova anual, sendo mais intensa nos meses frios. 131-330 mm ML e 147-275 dias foram os mínimos e os máximos encontrados para os machos maturos, enquanto que para as fêmeas foram 166-341 mm e 146-257 dias. A média do ML na maturidade foi de 181,2 mm e 156,3 mm para fêmeas e machos, respectivamente, e, 79,8% das fêmeas maturas estavam acasaladas. A fase paralarval teve uma média de 28,4 dias e não houve diferença sazonal e no sexo. O crescimento (incremento médio diário ML) dos calamares eclodidos na ‘estação quente’ e que cresceram como juvenis e maturos na ‘estação fria’ foi maior do que aqueles eclodiram na ‘estação fria’. O oposto foi observado para os calamares que eclodiram na ‘estação fria’. De acordo com estes resultados, Illex argentinus pquenos e maturos, desovam e eclodem no sul do Brasil em todas as estações e têm uma fase paralarval menor do que os exemplares de latitudes mais altas. A mistura de calamares pequenos eclodidos por todo o ano e calamares maiores desovantes de inverno é sugerido. / Specimens of Illex argentinus from commercial trawl catches along Southern Brazil were sampled monthly for dorsal mantel length (ML), sex, age and maturity from March 2007 to January 2008 in order to compare the cold season (June to November) and the warm season (December to May). Males (51.5%, 106-330 mm, 96-275 days) and females (48.5%, 114-341 mm, 124-257 days) were sampled. ML frequency distributions showed that small specimens occurred year round while larger males and females occurred only in the cold season. Back-calculated hatching dates showed year-round spawning, which is more intense in cold months. Mature males were 131-330mm and 147-275 days and females were 166-341 mm and 146-257 days. Mean ML’s at maturity were 181.2 mm and 156.3 mm for females and males, respectively, and 79.8% of the mature females was mated. The mean paralarval phase was 28.4 days without seasonal and sex differences. Growth (daily mean ML increment) of squids hatched in the warm season that grew as juveniles and matured in the cold season was higher than the growth of the ones hatched in the cold season. The opposite was observed in squids that hatched in the cold season. According to these results, small sized Illex argentinus that mature, spawn and hatch in southern Brazil in all seasons have a shorter paralarval phase than specimens in higher latitudes. The mixture of small sized squids hatching year round and large sized squid spawning in winter is suggested.
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Dinâmica Populacional na Região Metropolitana de Goiânia: fluxos e mobilidades / Dynamics of the Metropolitan Region of Goiânia: flows and mobilities

Souza, Johnathan dos Santos de 21 December 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-03-08T10:45:48Z No. of bitstreams: 2 Dissertação - Johnathan dos Santos de Souza - 2016.pdf: 4001525 bytes, checksum: 32f90a70b4994d9cb088187e048313c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-08T11:29:43Z (GMT) No. of bitstreams: 2 Dissertação - Johnathan dos Santos de Souza - 2016.pdf: 4001525 bytes, checksum: 32f90a70b4994d9cb088187e048313c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-08T11:29:43Z (GMT). No. of bitstreams: 2 Dissertação - Johnathan dos Santos de Souza - 2016.pdf: 4001525 bytes, checksum: 32f90a70b4994d9cb088187e048313c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present work had as objective to analyze a population dynamics of the Goiânia metropolitan area (RMG), from the beginning of the decade of 1990 until the first decade of the 21st century, along with the factors of its territorial formation. The data used were extracted from the Demographic Data (1991,2000 and 2010), the Atlas of Human Development 2013 and the Information Technology Department of the Brazilian Public Health Care System (DataSUS). The analyzes showed that the population growth has intensified over the years in the municipalities of the surroundings south, west and east of the metropolis. On the other hand, the distribution is concentrated only in five municipalities, all located around the capital. Regarding migrations, we noticed that most of the migration flows are interstate, with the majority coming from only four Brazilian states. In relation to the migration flows within the RMG, the migration between core and peripheral regions is still the one that stands out. The data also showed that the majority of the population of metropolitan municipalities is made up of migrants, except Goiânia. The pendulum migration was also analyzed, and we noticed that the greater flows of workers and students left / leave the most populous municipalities of the region, demonstrating the high degree of articulation between these and the metropolitan nucleus. And lastly, most of the population is made up of young people, which means that they are part of the economic workforce. Finally, the work contributes to the understanding of one of the elements of metropolitan complexity, as well as providing subsidies for further work, and the formulation of public policies by the public municipal and state managers. / O presente trabalho analisa a dinâmica populacional da Região Metropolitana de Goiânia (RMG), a partir do início da década de 1990 até a primeira década do século XXI, juntamente com os fatores de sua formação territorial. Os dados utilizados na pesquisa foram extraídos dos Censos Demográficos (1991,2000 e 2010), do Atlas do Desenvolvimento Humano 2013 e do Departamento de Informática do SUS (DataSus). As análises mostraram que o crescimento populacional se intensificou ao longo dos anos nos municípios do entorno sul, oeste e leste da metrópole. Por outro lado, a distribuição se concentra apenas em cinco municípios, ambos localizados ao redor da capital. Já em relação às migrações, notamos que a maior parte dos fluxos migratórios são interestaduais, sendo que a maior parte provêm de apenas quatro estados brasileiros. Em relação aos fluxos migratórios dentro da RMG, a migração núcleo-periferia ainda é a que se destaca. Os dados também mostraram que a maior parte da população dos municípios metropolitanos é formada por migrantes, exceto, Goiânia. A migração pendular também foi analisada, e notamos que os maiores fluxos de trabalhadores e estudantes saíram/saem dos municípios mais populosos da região, ddemonstrando o alto grau de articulação entre esses e o núcleo metropolitano. E por fim, a maior parte da população é formada por pessoas jovens, o que implica dizer que fazem parte da P.E.A econômica. E por último, o trabalho contribui para o entendimento de um dos elementos da complexidade metropolitana, além de apresentar subsídios para trabalhos mais aprofundados, como também, na formulação de políticas públicas por parte dos gestores públicos municipais e estaduais.

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