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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

Simulação computacional de eventos termo-hidraulicos transitorios em multicircuitos com multibombas

Veloso, Marcelo Antonio 02 October 2003 (has links)
Orientadores: Roger Josef Zemp, Paulo de Carvalho Tofani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-03T15:26:11Z (GMT). No. of bitstreams: 1 Veloso_MarceloAntonio_D.pdf: 10344720 bytes, checksum: e173f03cd07f8090cdc60aacf528de23 (MD5) Previous issue date: 2003 / Resumo: O programa computacional P ANTERA-2 (Programa para Análise Termo-hidráulica de Reatores a Água, Versão 2), cujos fundamentos são descritos neste trabalho, efetua a análise por subcanais de feixes de varetas em conjunção com a simulação de múltiplos circuitos. O programa resolve simultaneamente as equações de conservação da massa, dos momentos axial e lateral e da energia para a geometria de subcanais acopladas com as equações de balanço que descrevem o escoamento de um fluido em um número arbitrário de circuitos de remgeração conectados a um vaso de pressão que contém o feixe. Atendo-se à formulação de subcanais, a estratégia computacional básica de P ANTERA-2 provém dos códigos COBRA, mas um método implícito alternativo de solução orientado para o campo de pressões é usado para resolver as aproximações de diferenças finitas das leis de balanço. Os resultados previstos pelo modelo de subcanais compreendem as distribuições de densidades, entalpias, vazões de massa e pressões nos subcanais. O modelo de circuitos prevê as vazões nos circuitos individuais, a vazão total através do vaso de pressão e as velocidades de rotação das bombas em função do tempo subseqüente à falha de qualquer número das bombas de circulação. Os transitórios de vazão nos circuitos podem ser ocasionados pelas perdas de potência elétrica, ruptura de eixos e travamento de rotores das bombas. As variações nas velocidades de rotação das bombas em função do tempo são determinadas através de um balanço de torques. A altura de recalque e o torque hidráulico das bombas são calculadas em função da velocidade e da vazão com duas curvas homólogas polares fornecidas ao programa na forma tabular. Para ilustrar a capacidade analítica de P ANTERA-2, três problemas-exemplo são apresentados e discutidos. Comparações entre resultados calculados e medidos indicam que o programa reproduz com boa precisão dados experimentais de temperaturas de saída de subcanais e de fluxos de calor críticos em feixes de 5x5 varetas. Observa-se támbém uma boa concordância entre as curvas teóricas previstas por P ANTERA-2 e valores medidos para as velocidades de rotação das bombas e vazões de massa nos circuitos primários da central nuclear Angra-2, quando suas quatro bombas principais são simultaneamente desligadas para simular o evento de declínio de vazão. Palavras-chave: análise por subcanais, código de subcanais, códigos cobra, análise de circuitos de escoamento, acidente de falha de bombas / Abstract: PANTERA-2 (from Programa para Análise Termo-hidráulica de Reatores a ÁguaProgram for Thermal-hydraulic Analysis of Water Reactors, Version 2), whose fundamentals are described in this work, is intended to carry out rod bundle subchannel analysis in conjunction with multiloop simulation. It solves simultaneously the conservation equations of mass, axial and lateral momentum, and energy for subchannel geometry coupled with the balance equations that describe the fluid flows in any number of coolant loops connected to A pressure vessel containing the rod bundle. As far as subchannel analysis is concemed, the basic computational strategy of P ANTERA-2 comes from COBRA codes, but an altemative implicit solution method oriented to the pressure field has been used to solve the finitedifference approximations for the balance laws. The results provided by the subchannel mode1 comprise the fluid density, enthalpy, flow rate, and pressure fields in the subchannels. The loop model predicts the individualloop flows, total flow through the pressure vessel, and pump rotational speeds as a function of time subsequent to the failure of any number of the coolant pumps. The flow transients in the loops may initiated by partial, total or sequentialloss of electric power to the operating pumps. Transient events caused by either shaft break or rotor locking may also be simulated. The changes in rotational speed of the pumps as a function of time are determined from a torque balance. Pump dynamic head and hydraulic torque are calculated as a function of rotational speed and volumetric flow from two polar homologous curves supplied to the code in the tabular form In order to illustrate the analytical capability of P ANTERA-2, three sample problems are presented and discussed. Comparisons between calculated and measured results indicate that the program reproduces with a good accuracy experimental data for subchannel exit temperatures and critical heat fluxes in 5x5 rod bundles. It is also observed a good correspondence between the theoretical curves predicted by P ANTERA-2 and measured values for pump rotational speeds and mass flow rates in the primary loops of Angra-2 nuclear power plant, when the four main coolant pumps are simultaneously switched off to simulate the flow decline evento / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química
202

Pulse-shape studies with coplanar grid CdZnTe detectors and searches for rare nuclear decays with the COBRA experiment

Zatschler, Stefan 09 October 2020 (has links)
The inference of massive neutrino states through the observation of flavor oscillations boosted the importance of direct and indirect mass searches, including the search for the hypothesized neutrinoless double beta decay (0νββ-decay). Nowadays, the search for this ultra-rare nuclear transition is one of the most active research fields at the intersection of nuclear, particle and astroparticle physics. Its main and evident feature is the explicit violation of the total lepton number, which is an accidentally conserved quantity in the Standard Model of particle physics, and would prove the Majorana nature of neutrinos. This, in turn, would support the theoretical explanation of the origin of the observed baryon asymmetry in the universe through the process of leptogenisis and could shed light on the role of neutrinos in the early universe’s structure formation. For the theoretical description of the 0νββ-decay, nuclear structure effects play an important role as they may affect considerably the decay rate. These nuclear effects are summarized as the nuclear matrix elements (NMEs), containing information about the initial and final states of the involved atomic nuclei and the decay mechanism. Under the assumption of light Majorana neutrino exchange, the inverse half-life is proportional to the effective Majorana neutrino mass, a kinematic phase-space factor, the involved NMEs and the fourth power of the weak axial-vector coupling gA. The search for the 0νββ-decay is driven by experiments and an accurate description of the nuclear structure effects is essential to estimate the required sensitivity to cover a certain mass range. In order to match theoretical calculations and the results of β-decay and ββ-decay studies, there is a scientific discussion regarding quenching effects of gA in nuclear media. Different methods are being investigated to determine an effective gA at the energy scale of nuclear transitions. One of those recently proposed methods exploits the dependency of the spectrum-shape of highly forbidden β-decays on gA. An ideal candidate for such an investigation is the fourfold forbidden non-unique β-decay of Cd-113, which is the most prominent signal in the current stage of the COBRA experiment searching for 0νββ-decays with cadmium zinc telluride (CZT) solid state detectors. The detector material CZT acts as a semiconductor at room temperature and contains intrinsically several candidates for rare nuclear transitions. The experiment is located at the LNGS underground facility in Italy, which is shielded against cosmic rays by a mean rock coverage of about 1400 m. In the present demonstrator phase, it consists of 64 coplanar grid (CPG) detectors that are arranged in four layers of 4 x 4 crystals. In the scope of this thesis, conventional and novel prototype CPG-CZT detectors, which are the basis for an anticipated large-scale experiment, are characterized by evaluating homogeneous and localized γ-ray irradiation measurements. Moreover, a novel pulse-shape discrimination (PSD) technique is established, optimized and applied in the analysis of the physics data obtained with the demonstrator array. The PSD optimization is complemented by dedicated laboratory measurements with the aim to create a pulseshape library of signal-like single-site events and high-energy cosmic muon interactions for which an analytic reconstruction model has been developed. For the first time, the COBRA demonstrator’s full exposure from Sept.’11 to Nov.’19 is analyzed, including a detailed background characterization as well as an automatized data partitioning to identify periods with increased backgrounds. The main subject is the study of the Cd-113 β-decay’s spectrum-shape to address the quenching of gA in lowmomentum exchange nuclear processes. The analysis of the experimental data is carried out in the context of three nuclear frameworks and confirms the idea of a significantly quenched gA. Furthermore, the data are analyzed with respect to the 2νββ-decay of Cd-116 and the long-lived α-decay of Pt-190 as a localized contaminant in the CZT detectors’ electrode metalization. Finally, the prospects of a search for excited state transitions of the ββ-nuclides Cd-116 and Te-130 are studied with elaborate Monte-Carlo simulations. The analysis section is concluded with an estimate of the achievable 0νββ-decay half-life sensitivity for multiple ββ-nuclides given the full exposure of the COBRA demonstrator and the recently achieved upgrade to the COBRA eXtended DEMonstrator (XDEM).
203

Simulating SCWR thermal-hydraulics with the modified COBRA-TF subchannel code

Lokuliyana, Wikumpiya Dinusha 04 1900 (has links)
<p>Among the six GEN-IV reactor concepts recommended by the Gen-IV International Forum, supercritical water-cooled reactors (SCWR) have gained significant interests due to its economic advantage, technology and experience continuity. In the last few years, extensive R&D activities have been launched covering the various aspects of SCWR development, especially in thermal-hydraulic analysis. In Canada, most R&D projects are led by AECL or NRCan.</p> <p>SCWR design and development require the modification of simulation codes used for design and safety demonstration of subcritical water-cooled reactors. This study modifies the subchannel code COBRA-TF, applicable to only subcritical water-cooled reactors, to a new version COBRA-TF-SC, applicable to both supercritical and subcritical water-cooled reactors. Supercritical water property data tables and supercritical water property formulations are implemented. Supercritical water heat transfer and pressure drop correlations are also added. The saturation curve in the subcritical model is extended by introducing a pseudo two-phase region at supercritical pressures to avoid any numerical instabilities consistent with other studies.</p> <p>Some simple fuel bundle experimental data on the flow and temperature distribution are used to evaluate the code. The fuel bundle experiment is simulated with both COBRA-TF-SC and AECL's ASSERT-PV-SC. The COBRA-TF-SC predicted results show good agreement with the experimental data and results obtained from ASSERT-PV-SC, demonstrating good feasibility and accuracy of this code. COBRA-TF-SC is then used to predict the detailed thermalhydraulics behaviour of the 62-element Canadian SCWR fuel bundle design. The advantage of COBRA-TF-SC is that it can accommodate transcritical flow conditions whereas the existing subchannel codes for SCWRs cannot.</p> / Master of Applied Science (MASc)
204

Une spécificité Cobra, les oeuvres collectives: émergence d'une pratique et exemplarité de Christian Dotremont / One of the Cobra's specificity, collective works: emergence of Christian Dotremont's practice and exemplary.

Andrieu, Mélanie 30 September 2011 (has links)
Cette thèse est une étude du mouvement Cobra à travers les œuvres collectives, une de ses composantes caractéristiques. Il s’agit tout d’abord de comprendre le mouvement, ses origines et influences, ainsi que sa visée d’un art libre, ouvert, expérimental, partie prenante de la vie. Dans un contexte social d’après-guerre, souvent politisé, Cobra défend l’action collective, définie notamment dans les notions d’antispécialisme et d’interspécialisme. Il convient de mettre en exergue les origines de cette pratique, et saisir les divers aspects qu’elle arbore, notamment au travers de revues, d’expositions ou de créations partagées. Le poète Christian Dotremont, animateur et âme de Cobra, favorise le travail de collaboration et contribue à son développement en stimulant les rencontres artistiques. Il se fait le passeur et le permanent "agitateur"» de cette notion. Les peintures-mots qu’il crée avec d’autres artistes participent à sa réflexion majeure sur l’écriture et la peinture. Ce lien interpelle quelques artistes belges comme Pierre Alechinsky, mais il passionne Christian Dotremont qui ne cesse de multiplier les expériences à ce propos, pour aboutir à ce qu’il nomme les logogrammes, remarquable fusion de la peinture et de la poésie, et aboutissement de toute une vie de recherche. <p>Ce travail est structuré en trois points. Le premier établit une étude du contexte artistique et social des années précédent Cobra puis la mise en place du groupe. Le second aborde les années d’intense activité "officielle" du groupe, au service du collectif. Enfin, le troisième propose de suivre l’évolution post-Cobra des œuvres collectives et des recherches sur l’écriture et la peinture. / This thesis is a study of the Cobra movement through one of its characteristic components: the collective works. First of all it's about understanding the movement, its origins (three countries), its influences and its purpose of a free art, open, experimental, involvement with life. In a social after-war context, often politicized, Cobra defends collective action, notably defined in concepts of anti-specialism and inter-specialism. We should therefore underline the origins of this practice and undestand different aspects that it shows, in particular through publications, exhibitions or shared creations. The poet Christian Dotremont, leader and soul of Cobra, promotes cooperative work by collaboration and contributes to its development by stimulating artistic meetings. He is the purveyor and permanent "agitator" of this concept. The words-paintings that he creates with other artists, take part of his major thinking about writing and painting. This link interpellates a few Belgian artists like Pierre Alechinsky, but it fascinates Christian Dotremont who keeps experimenting on it, in order to reach what he calls the logograms, a remarkable fusion of painting and poetry, and a culmination of a life-time of research.<p>This work is structured in three parts. The first one draws a study of the artistic and social context of the years preceding Cobra and the setting up of the group. The second one talks about years of intense "official" activity of the group serving collective way of work. Finally, the third one offers to follow the post-Cobra evolution of collective works and researches about writing and painting. / Doctorat en Histoire, art et archéologie / info:eu-repo/semantics/nonPublished
205

Beneath the raptor’s wings : the avian composition grasping the symbol for eternity in Egypt

Klop, Damian J.R. 03 1900 (has links)
Thesis (MPhil (Ancient Studies)--University of Stellenbosch, 2008. / A particular motif in Egyptian art is that of avians. This is frequently depicted in a significant number and variety of visual sources from the tomb of Tutankhamun (KV 62) (1336-1327 BC) and other find contexts throughout Egyptian history from c. 3000 BC, but is little understood. The motif mostly depicts an avian creature with wings outstretched, talons grasping the Egyptian hieroglyph symbol for eternity (shen). In some instances the avian’s falcon or vulture body or parts of the body is/are replaced with parts of another creature, namely that of a snake, cobra, ram, human, duck, or a hieroglyph sign. A study was undertaken to assess how and why this avian motif was composed and what the function in Egyptian culture was. A manual search of published material for relevant visual sources depicting specific versions of the avian motif was undertaken and selected sources were indexed into a representative graphical database including one hundred and ninety-one items. Textual sources (academic literature and literature from ancient Egypt) were then consulted to support and/or expand on the iconographic, symbolic, and functional aspects of the motif: - At the iconographic level, the historical development and ‘structural dynamics’ of the motif are investigated to deduce the artistic rules that applied to its creation. - At the symbolic level, the symbolic meaning of the artwork is ascertained by theorizing on the meaning of the motif and its parts in an Egyptian context. - At the functional level, the function of the artwork is ascertained by investigating how the motif’s symbolism was intended to be applied to benefit the individual. The results of this research is that the avian motif developed over time according to strict artistic rules; that it symbolized the king, eternity and protection; and that its function was to protect the king in all phases of his existence in a political and mythological context in order to ensure that the he would attain an eternal life in the afterlife. In the mind of the ancient Egyptian this was achieved through the transference of the avian motif’s magical qualities to the user. The intended outcome of this study is to highlight the avian motif’s importance in the context of the ancient Egyptian culture.
206

Clonagem, expressão e estudo de alguns cDNAs codificando proteínas estruturalmente relacionadas às alfa neurotoxinas da glândula de veneno da cobra coral Micrurus corallinus (Serpentes, Elapidae). / Cloning, expression and study of some cDNAs codifying proteins structurally related to the alpha neurotoxins of the venom gland from coral snake Micrurus corallinus (Serpentes, Elapidae).

Silva, Alvaro Rossan de Brandão Prieto da 28 January 2002 (has links)
De uma biblioteca de cDNA da glândula de veneno da cobra coral brasileira Micrurus corallinus foi isolada uma seqüência denominada NXH8. Esta seqüência de cDNA apresenta similaridade estrutural com a família de toxinas de serpentes em 'três dígitos' ricas em pontes dissulfeto. A subclasse melhor conhecida nesta família, são as alfa neurotoxinas. Uma outra seqüência distinta, denominada NXH1 e suas isoformas NXH3 e NXH7, foram isoladas anteriormente. Pertencem à mesma família de toxinas e estão presentes na mesma biblioteca. Alguns resultados da caracterização de NXH1, são utilizados neste estudo, em comparação com NXH8. Algumas características estruturais tornam a seqüência NXH8 diferente da classe usual das alfa neurotoxinas, vindo a constituir possivelmente uma nova subclasse da família. A proteína NXH8 foi expressa em diversos vetores de expressão em Escherichia coli. A proteína recombinante, expressa pelo vetor pRSET C - NXH8 foi utilizada para imunizar camundongos. O soro contra NXH8, assim como o soro anti - elapídico do Instituto Butantan, reconhece a toxina recombinante em ELISA e Western blot. O soro anti - NXH8 detecta apenas uma banda do veneno de M. corallinus em Western blot, mas apresenta reatividade cruzada com componentes do veneno de alguns elapídeos neotropicais e do velho mundo. Em contraste, dados anteriores demonstraram que o soro anti - NXH1 é específico para um componente único do veneno de M. corallinus. O veneno de M. corallinus tem alfa neurotoxinas que bloqueiam o receptor pós - sináptico nicotínico de acetilcolina nas membranas do músculo esquelético de ratos. O soro anti - NXH8 é capaz de impedir a ligação de componentes do veneno bruto a esses receptores. Já o soro contra NXH1 não apresenta a mesma capacidade inibitória. Isto indica que NXH8 tem afinidade pelo receptor nicotínico muscular de acetilcolina, ou que NXH8 compartilha de um epítopo neutralizante presente também nas alfa neurotoxinas do veneno da cobra coral M. corallinus. / A cDNA sequence encoding a putative new toxin, NXH8, was isolated from the cDNA library constructed from the venom gland of the Brazilian coral snake, Micrurus corallinus. This sequence shows a structural similarity with the snake toxin family known as 'three-fingered' toxins, a family of toxins with approximately 60 to 70 amino acids and usually 4 to 5 disulfide bonds. Irrespective of whether these proteins are functionally different, their amino acid sequences can be readily aligned, using 8 half-cystines as conserved elements, suggesting the presence of common structural features. The best known subclass of three-finger-type toxins are the curaremimetic toxins, also called alpha-neurotoxins, found in most venoms from Elapid and Sea snakes. Another toxin with a distinct sequence, known as NXH1 and its isoforms NXH3 and NXH7 had been previously isolated. They belong to the same family of toxins and were characterized from the same cDNA library. In the present study, a comparative biochemical, pharmacological and structural analyses of NXH1 and NXH8 were described. Few structural characteristics of NXH8 seem to indicate that it differs from the usual class of alpha – neurotoxins, belonging, possibly, to a new subclass of 'three-finger' toxins. The NXH8 protein was expressed in various E. coli expression vectors and the resulted recombinant toxin from pRSETC-NXH8 plasmid was used as a "toxoid" for mice immunization. The anti - NXH8 sera, as well as the anti – elapid sera from the Butantan Institute, recognized the recombinant toxin by both ELISA and Western blot assays. In contrast to the claim that anti - NXH1 sera is specific to one component of M. corallinus’s venom, the anti – NXH8 sera show cross reactivity to venom of some Neotropical and Old World elapids. The M. corallinus's venom contains alpha – toxins, which inhibit post-synaptic nicotinic acetylcholine receptor of neonatal rat skeletal muscle membrane. The anti - NXH8 serum was capable of blocking the binding of the components of the crude venom to these receptors. In contrast, the anti – NXH1 serum did not show this inhibitory effect. This indicates that either NXH8 presents affinity for muscular nicotinic acetylcholine receptor or it shares a neutralizing epitope also present in M. corallinus’s alpha – neurotoxins.
207

Morfologia e taxonomia de Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae) e seu relacionamento mimético com corais verdadeiras na Amazônia

ALMEIDA, Paula Carolina Rodrigues de January 2012 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-02-15T20:50:17Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_MorfologiaTaxonomiaAtractus.pdf: 5634526 bytes, checksum: 6358e290a16df2173fc8f4d35e8a1ce0 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-02-18T15:28:03Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_MorfologiaTaxonomiaAtractus.pdf: 5634526 bytes, checksum: 6358e290a16df2173fc8f4d35e8a1ce0 (MD5) / Made available in DSpace on 2013-02-18T15:28:03Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_MorfologiaTaxonomiaAtractus.pdf: 5634526 bytes, checksum: 6358e290a16df2173fc8f4d35e8a1ce0 (MD5) Previous issue date: 2012 / A coloração animal é um importante atributo biológico com diferentes funções relacionadas às estratégias de vida adotadas pelos indivíduos no ambiente, como a termorregulação, a defesa e a comunicação inter e intraespecífica. O mimetismo é talvez, um dos mais importantes mecanismos biológicos de comunicação, frequentemente envolvendo similaridade de cor com conotação defensiva. Os sistemas miméticos refletem um complexo processo de evolução, que acentua semelhanças morfológicas ou comportamentais entre duas ou mais espécies, garantindo vantagens adaptativas em pelo menos uma delas. Apesar de comum entre os invertebrados, o mimetismo também pode ser observado em grupos de vertebrados como lagartos e serpentes, por exemplo. Dentre os exemplos mais comuns de mimetismo em serpentes são descritas as relações entre os corais verdadeiras e falsas. A falsa-coral, Atractus latifrons (Günther, 1868) é endêmica da Amazônia e ocorre nos territórios de Brasil, Colômbia, Guiana Francesa, Peru, Suriname e Venezuela. Em função da semelhança cromática de seus diferentes padrões, esta espécie foi relacionada à algumas espécies de corais verdadeiras do gênero Micrurus que também apresentam distribuição amazônica. Embora a variação cromática desta espécie tenha sido relatada por alguns autores, algumas questões sobre o polimorfismo intraespecífico e sua relação com a distribuição geográfica, assim como a relação mimética com as corais verdadeiras de Micrurus ainda não foram estudadas. Com o objetivo de contribuir com a elucidação destas questões, este estudo foi organizado em dois capítulos: no primeiro capítulo, intitulado “Variação morfológica e taxonomia de Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae)”, foram apresentadas as variações da morfologia externa e hemipeniana da espécie, incluindo sua redescrição e descrição do holótipo, além das descrições dos padrões cromáticos e análise de dimorfismo sexual; e no segundo capítulo, intitulado “Relações miméticas entre Atractus latifrons e corais verdadeiras na Amazônia”, foram identificados os possíveis modelos miméticos para A. latifrons, inferindo suas relações miméticas através da análise de co-ocorrência e apresentando mapas de distribuição dos padrões miméticos entre as espécies envolvidas. / Animal coloration is an important biological attribute with different functions related to the strategies adopted by individuals in the environment, such as thermoregulation, defense and inter and intraspecific communication. The mimicry is perhaps one of the most important biological communication mechanisms, often involving similarity of color with a defensive connotation. Systems mimetics reflect a complex evolution process that accentuates similarities morphological or behavioral between two or more species guaranteeing adaptive advantages at least one. Though common between invertebrates, mimicry also observed in vertebrate groups as lizards and serpents eg. For examples common mimicry snakes are described relations between corals true and false. The false coral, Atractus latifrons (Günther, 1868) is endemic in the Amazon and occurs in the Brazil, Colombia, French Guiana, Peru, Suriname and Venezuela. Due to the similarity of their different color patterns, this species was related to some species of the genus Micrurus coral snakes that also have Amazon distribution. Although the chromatic variation of this species has been reported by some authors, some questions about the intraspecific polymorphism and its relation to geographic distribution, as well as the mimetic relationship with the coral snakes Micrurus not yet been studied. With the purpose of contribute to the elucidation of these issues, this study was organized into two chapters: In first entitled "Variation Morphological and Taxonomy Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae)" were presented morphological variations species including descriptions their standards chromatic and variations morphological intraspecific A. latifrons and analysis sexual dimorphism group; in second chapter entitled "Relations mimicry between Atractus latifrons and corals true Amazon" were identified for possible models mimetics A. latifrons, inferring their mimetic relationships through the analysis of co-occurrence and distribution maps showing patterns among mimetic species involved.
208

Composição e diversidade de serpentes em um mosaico de habitats no município de Urbano Santos, Maranhão

LIMA, Jucivaldo Dias 15 April 2003 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-08-23T15:40:17Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_ComposicaoDiversidadeSerpentes.pdf: 75792721 bytes, checksum: ad9917b62d8403dcb9878cac693c28a7 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-08-30T14:48:37Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_ComposicaoDiversidadeSerpentes.pdf: 75792721 bytes, checksum: ad9917b62d8403dcb9878cac693c28a7 (MD5) / Made available in DSpace on 2013-08-30T14:48:37Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_ComposicaoDiversidadeSerpentes.pdf: 75792721 bytes, checksum: ad9917b62d8403dcb9878cac693c28a7 (MD5) Previous issue date: 2003 / This study presents results of a year of field observations on the snake fauna sampled in a habitat mosaic ecompassing flooded and non-flooded forest types, eucalyptus plantations and open vegetation areas, at Urbano Santos, Maranhão State of Brasil. The area is covered by Savanna vegetation and the climate is tropical megathermical, with annual rainfail around 1800mm. The yaer of study (2001) was drier than average rainfall (1197.5mm). Sample were made from January to December 2001, during 24 field trips, lasting for days each 15 day period. Sampling effort was 768h/oberver including diurnal and nocturnal visual search. Each habitat was sampled by randorn linear transect chosen by chance. During the study, 114 snakes belonging to six families, 27 genera and 32 species were captured. For each species data smout-vet length, ativity period, juvenile presence, spatial distribution and microhabitat are presented. Among the 32 species registred, six were new record for Maranhão State (Apostolepis cearensis, Helicops leopardinus, Oxyrhopus trigeminus, Psomophis joberti, Waglerophis merremíí e Micrurus ibiboboca). Among the species registered, 40.1% were arboreal, 25.0% were subterraneous, 21.9 % terrestrial and 12.5% aquatic, even though some species occupied more than one microhabitat. Most species occurred in flooded and non-flooded forests, and open vegetation areas. In general, similarity between habitats was low; only the non-flooded forest, and open vegetations areas shared more than 60% of species. Estimates of species richness according to various estimators, indicated that the number of species observed was lower than expected, varying between 38 (bootstrap) and 58 (Chao 2). Compementarity between the habitat showed more similarity between flooded and non-flooded forest to open vegetation area. The sanke fauna in the area appears to be most similar to that recorded from the Ceará State mountaing range. The results represent the first contribution to the knowledge of the snake diversity in the region and offer first data for future projects on monitoring snake fauna and habitat status in the area. / Este estudo apresenta os resultados de um ano de observações de campo para amostragens da fauna de serpentes em um mosaico de habitats, abrangendo matas de terra firme e inundável, plantações de eucalipto e áreas abertas, na Fazenda Santo Amaro, Município de Urbano Santos, Maranhão. A região é dominada por vegetação de Cerrado e possui clima tropical rnegatérmico, com total pluviométrico anual em torno de 1800-mm. O ano de estudo (2001) apresentou-se mais seco que a média anual, com 1197,5mm. As amostragens foram realizadas durante 24 excursões quinzenais, com duração de quatro dias cada, entre janeiro e dezembro de 2001. Estas amostragens totalizaram 768h/observador de procuras visuais diurnas e noturnas, onde os diferentes habitats foram amostrados por sorteios randomizados, nos diversos horários do dia, obtendo o mesmo número de horas de amostragem nas diferentes épocas do ano. Foram capturadas 114 serpentes, representadas por seis famílias, vinte e sete gêneros e trinta e duas espécies. Para cada espécie são apresentadas informações sobre o tamanho, período de atividade, classe etária, habitat e microhabitat. Das 32 espécies amostradas na área seis foram registradas pela primeira vez para o Maranhão como, Apostolepis cearensis, Helicops leopardinus, Oxyrhopus trigeminus, Psornophis joberti, Waglerophis merremii e Micrurus ibiboboca, Em geral, a maioria das espécies registradas tem distribuição Amazônica. Entre as espécies da área, 40,1% foram arborícolas, 25% fossóreas/criptozóicas, 21,9% terrícolas e 12,5% aquáticas, embora algumas espécies ocuparam mais de um microhabitat. A maioria das espécies ocorreu nos ambientes de mata de terra firme, mata inundável e área aberta. A similaridade entre os habitats da área, de modo geral, foi muito baixa, sendo que apenas a mata de terra firme e área aberta tiveram mais de 60% de espécies em comum. A menor complementariedade de fauna ocorreu entre os habitats "mata de terra firme" e "área aberta" e "mata inundável" e "área aberta". Em relação a outras áreas a maior similaridade entre as áreas ocorreu com as serras e maciços do Estado do Ceará. A riqueza estimada para a área, segundo os índices e estimadores utilizados nas análises, indicam que o número de espécies observadas está abaixo do estimado, que variou entre 38 (bootstrap) e 58 (Chao 2) espécies. Esses resultados representam uma primeira contribuição sobre a diversidade de serpentes na região e oferece subsídios para possíveis programas de monitoramento da fauna de serpentes e da situação dos habitats na área.
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Biologia reprodutiva e alimentar de Liophis reginae semilineatus (Wagler,18424) e Liophis taeniogaster jan, 1863 (Serpentes, Colubridae, Xenodontinae) da Amazônia oriental, Brasil

CASTRO, Luiz Paulo Printes Albarelli de January 2007 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-09-05T15:11:09Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_BiologiaReprodutivaAlimentar.pdf: 3990837 bytes, checksum: 7b151f0ef61d00aae40a746afb50cf5a (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-09-11T17:07:24Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_BiologiaReprodutivaAlimentar.pdf: 3990837 bytes, checksum: 7b151f0ef61d00aae40a746afb50cf5a (MD5) / Made available in DSpace on 2013-09-11T17:07:24Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_BiologiaReprodutivaAlimentar.pdf: 3990837 bytes, checksum: 7b151f0ef61d00aae40a746afb50cf5a (MD5) Previous issue date: 2007 / O presente trabalho trata de um estudo detalhado sobre a biologia reprodutiva e alimentar de Liophis reginae semilineatus e Liophis taeniogaster, de populações restritas a Amazônia Oriental, através da análise de dimorfismo sexual, maturidade sexual, ciclo reprodutivo, fecundidade, composição da dieta e relações presa-predador. As duas espécies são simpátricas, porém não foram realizadas comparações entre ambas, devido a distância filogenética (Moura-Leite, 2001), por apresentarem diferenças quanto aos recursos alimentares e microhábitats freqüentados (Cunha & Nascimento, 1993), sendo apresentadas em dois capítulos distintos, o primeiro tratando da biologia reprodutiva e alimentar de Liophis reginae semilineatus e o segundo capítulo tratando da biologia reprodutiva e alimentar de Liophis taeniogaster.
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Análise da variação morfológica de Dipsas catesbyi (Sentzen, 1796) e Dipsas pavonina Schlegel, 1837 (Serpentes: Colubridae: Dipsadinae)

LIMA, Ana Caroline de January 2006 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-09-11T17:11:00Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AnaliseVariacaoMorfologica.pdf: 2957206 bytes, checksum: 2aca80d5e0917b292ade905b5c9fa8d1 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-09-13T14:26:24Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AnaliseVariacaoMorfologica.pdf: 2957206 bytes, checksum: 2aca80d5e0917b292ade905b5c9fa8d1 (MD5) / Made available in DSpace on 2013-09-13T14:26:25Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AnaliseVariacaoMorfologica.pdf: 2957206 bytes, checksum: 2aca80d5e0917b292ade905b5c9fa8d1 (MD5) Previous issue date: 2006 / A subfamília Dipsadinae engloba 22 gêneros da fauna de colubrídeos neotropicais e 24 outros considerados incertae sedis, mas com caracteres comuns aos dipsadíneos. Os gêneros Dipsas, Sibon, Sibynomorphus e Tropidodipsas formalmente compõem a tribo Dipsadini a qual é considerado um grupo monofilético bem fundamentado. A tribo é caracterizada por serpentes que apresentam um alto grau de especialização morfológica, relacionado ao modo de alimentação e adaptações ao hábitat em que vivem. O gênero Dipsas inclui aproximadamente 32 espécies, distribuídas do México até a América do Sul, é constituído por serpentes de corpo delgado e alongado, com cabeça curta e proeminente, olhos grandes, pupilas verticais e ausência de sulco mentoniano. As espécies são notavelmente variáveis na coloração, número de escamas e outros caracteres morfológicos. Essa extrema variação tem dificultado a definição dos limites entre as espécies e a interpretação de padrões de variação geográfica. A grande variação morfológica dos caracteres presentes nas espécies D. catesbyi e D. pavonina, associada à dificuldade de identificação dos táxons e à escassez de informações sobre as suas distribuições geográficas, justificam a necessidade de uma análise mais detalhada destas espécies. Para tal, o presente estudo foi dividido em dois capítulos. O primeiro capítulo corresponde à análise da variação individual, sexual e geográfica de D. catesbyi e D. pavonina, e a comparação dos caracteres morfológicos entre as duas espécies. O segundo corresponde à análise da macroestrutura das glândulas cefálicas nestas duas espécies, relacionando-as com outros táxons de Dipsadinae. / The subfamily Dipsadinae contains about 22 genus of Neotropical fauna and 24 others considered incertae sedis, but with common characters to the Dipsadinae subfamily. The genus Dipsas, Sibon, Sibynomorphus and Tropidodipsas compose the Dipsadini tribe, which is considered a well-based monofiletic group. The tribe is characterized by snakes with a high degree of morphologic specialization, related to the way of feeding and to adaptations to the habitat. The Dipsas genus includes approximately 32 species, distributed from Mexico to South America, it is constituted by thin and elongated snakes, with short and prominent head, great eyes, vertical pupils and absence of mental groove. The species are visible variable in coloration, number of scales and others morphologic characters. This extreme variation has made it difficult to define the limits between the species and to interpret patterns of geographic variation. The great morphologic variation of characters in D. catesbyi and D. pavonina, associate to the difficulty to identify taxons and the lack of information on geographic distributions, justify the necessity of a detailed analysis of these species. For that, the present study was divided in two chapters. The first one corresponds to the analysis of the individual, sexual and geographic variation of D. catesbyi and D. pavonina and a comparison of characters between the two species. The second one corresponds to the analysis of the macrostructure of the cephalic glands in these two species, relating them with others taxons of Dipsadinae.

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