Sistemas binários eclipsantes na missão CoRot

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conducão eletrônica e propriedades termodinâmicas da molécula de DNA

In this thesis, we study the thermo-electronic properties of the DNA molecule. For this purpose, we used three types of models with the DNA, all assuming a at geometry (2D), each built by a sequence of quasiperiodic (Fibonacci and / or Rudin-Shapiro) and a sequence of natural DNA, part of the human chromosome Ch22. The first two models have two types of components that are the nitrogenous bases (guanine G, cytosine C, adenine A and thymine T) and a cluster sugar-phosphate (SP), while the third has only the nitrogenous bases. In the first model we calculate the density of states using the formalism of Dyson and transmittance for the time independent Schr odinger equation . In the second model we used the renormalizationprocedure for the profile of the transmittance and consequently the I (current) versus V (voltage). In the third model we calculate the density of states formalism by Dean and used the results together with the Fermi-Dirac statistics for the chemical potential and the quantum specific heat. Finally, we compare the physical properties found for the quasi-periodic sequences and those that use a portion of the genomic DNA sequence (Ch22).

Mecanismos de alojamento de magmas granitóides :exemplo do plúton de Japi(RN)

This dissertation describes the igneous suites of the Japi granitoid pluton, intrusive in the Paleoproterozoic gneiss-migmatite complex of the eastern domain of the Seridó Belt, northeastern Brazil. Field relations show that the pluton is affected by strong deformation associated to the Brasiliano orogeny (known as the D3 phase) , with a NW-trending extensionalleft-hand senestral shear zone (the Japi Shear Zone, JSZ) bordering the intrusive body to the west. Four plutonic suites are found in the main pluton and as satellyte intrusions, besides Iate pegmatite and pink leucogranites. An alkaline granitoid suite, dominated by syenogranites bearing sodic augite (and subordinate hornblende), define a main elliptical intrusion. In its northern part, this intrusion is made up by concentric sheets, contrasting with a smaller rounded stock to the south. These granites display a pervasive solid-state S>L fabric developed under high T conditions, characterized by plastic deformation of quartz and feldspar. It is especially, developed along the border of the pluton, with inward dips. A regular magmatic layering is present sometimes, parallel to the tectonic foliation. The syntectonic emplacement as regards to the Brasiliano (D3) event is indicated by the common occurrence of dykes and sheets along transtensional or extensional sites of the major structure. Field relations attest to the early emplacement of the alkaline granites as regards to the other suites. A basic-to-intermediate suite occurs as a western satellyte body and occupying the southern tail of the main alkaline pluton. It comprises a wide variety of compositional terms, including primitive gabbros and gabbro-norites, differentiated to monzonitic intermediate facies containing amphibole and biotite as their main mafic phases. These rocks display transitional high-K calc-alkaline to shoshonitic affinities. Porphyritic monzogranite suítes commonly occur as dykes and minor intrusives, isolated or associated with the basic-tointermediate rocks. In the latter case, magma mingling and mixing features attest that these are contemporaneous igneous suites. These granites show K-feldspar phenocrysts and a hornblende+biotite+titanite assemblage, displaying subalkaline/monzonitic geochemical affinities. Both suites exhibit SL magmatic fabrics overprinting or transitional to solid-state D3 deformation related to the JSI. Chemical data clearly show that they are related to different parental magmas. Finally, a microgranite suite occurs along a few topographic ridges paralell to the JSI. It comprises dominantly granodiorites with a mineralogy similar to the one of the porphyritic granitoids. However, discriminant diagrams show their distinct calc-alkaline affinity. The granodiorites display an essencially magmatic fabric, even though an incipient D3 solid-state structure may be developed along the JSI. Intrusion relationships with the previous suites, as well as regards to the D3 structures, point to their Iate emplacement. All these suites are intrusive in a Paleoproterozoic, high-grade gneiss-migmatite complex affected by two previous deformation phases (D1, D2). The fabrics associated with these earlier events are folded and overprinted by the younger D3 structures along the JSZ. The younger deformation is characterized by NE-dipping foliations and N/NE-plunging stretching lineations. In the JSZ northern termination the foliation acquires an ENE orientation, containing a stretching lineation plunging to the south. Symmetric kinematic cri teria developed at this site confirms the transpressional termination of the JSZ, as also shown by orthorrombic quartz c-axis patterns. E-W-trending d extra I shear zones developed in the central part of the JSZ are interpreted as antithetic structures associated to the transtensional deformation along the JSZ. This is consistent with its extensional-transcurrent kinematics and a flat-and-ramp geometry at depth, as shown by gravimetric data. The lateral displacement of the negative residual Bouguer anomalies, as regards to the main outcropping alkaline pluton, may be modelized by other deeper-seated granite bodies. Based on numerical modelling it was possible to infer two distinct intrusion styles for the alkaline pluton. The calculated model values are consistent with an emplacement by sheeting for the northern body, as already suggested by satellyte imagery and field mapping. On the other hand, the results point to a transition towards a diapir-related style associated to the smaller. southern stock. This difference in intrusion styles may relate to intensity variations and transtensional sites of the shear deformation along the JSZ. Trace element and Sr and Nd isotopes of the alkaline granites are compatible with their derivation trom a more basic crustal source, as compared to the presently outcropping highgrade gneisses, with participation (or alternatively dominated by) of an enriched lithospheric mantle component. Like other igneous suites in the Seridó Belt, the high LlL contents and fractionated REE patterns of the basic rocks also point to an enriched mantle as the source for this kind of magmatism. Geochemical and isotope data are compatible with a lower crustal origin for the porphyritic granites. On the basis of the strong control of the JSZ on the emplacement of lower crustal (porphyritic and alkaline granites) or lithospheric mantle (basic rocks, alkaline granites or a component of them) magmas, one may infer a deep root for this structure, bearing an important role in magma extraction, transport and emplacement in the Japi region, eastern domain of the Seridó Belt

Incorporação do vínculo de suavidade no ajuste de histórico de reservatórios de petróleo

The history match procedure in an oil reservoir is of paramount importance in order to obtain a characterization of the reservoir parameters (statics and dynamics) that implicates in a predict production more perfected. Throughout this process one can find reservoir model parameters which are able to reproduce the behaviour of a real reservoir.Thus, this reservoir model may be used to predict production and can aid the oil file management. During the history match procedure the reservoir model parameters are modified and for every new set of reservoir model parameters found, a fluid flow simulation is performed so that it is possible to evaluate weather or not this new set of parameters reproduces the observations in the actual reservoir. The reservoir is said to be matched when the discrepancies between the model predictions and the observations of the real reservoir are below a certain tolerance. The determination of the model parameters via history matching requires the minimisation of an objective function (difference between the observed and simulated productions according to a chosen norm) in a parameter space populated by many local minima. In other words, more than one set of reservoir model parameters fits the observation. With respect to the non-uniqueness of the solution, the inverse problem associated to history match is ill-posed. In order to reduce this ambiguity, it is necessary to incorporate a priori information and constraints in the model reservoir parameters to be determined. In this dissertation, the regularization of the inverse problem associated to the history match was performed via the introduction of a smoothness constraint in the following parameter: permeability and porosity. This constraint has geological bias of asserting that these two properties smoothly vary in space. In this sense, it is necessary to find the right relative weight of this constrain in the objective function that stabilizes the inversion and yet, introduces minimum bias. A sequential search method called COMPLEX was used to find the reservoir model parameters that best reproduce the observations of a semi-synthetic model. This method does not require the usage of derivatives when searching for the minimum of the objective function. Here, it is shown that the judicious introduction of the smoothness constraint in the objective function formulation reduces the associated ambiguity and introduces minimum bias in the estimates of permeability and porosity of the semi-synthetic reservoir model

Beachrocks do Rio Grande Do norte: correlação entre os depósitos costeiros e os de zona costa-afora com base na faciologia, petrografia e diagênese

Beachrocks são rochas sedimentares formadas pela cimentação de sedimentos praiais por carbonato de cálcio em especial, calcita e/ou aragonita em zona de estirâncio. A ocorrência dessas rochas é bastante comum em diversas partes do globo, sobretudo em regiões com latitudes inferiores a 40º. O Rio Grande do Norte possui grande quantidade de beachrocks, os quais afloram tanto em regiões costeiras quanto em zona costa-afora. Os depósitos de beachrocks de zona costeira do referido estado têm sido estudados por diversos autores, os quais abordaram os mais variados temas desde o início do século XX. Por outro lado, os depósitos de zona costa-afora apesar de terem sido estudados por poucos autores têm ganhado atenção apenas nos últimos anos. Porém, nenhum trabalho até o presente fez algum tipo de estudo comparativo de cunho geológico entre os corpos de beachrocks presentes em ambas as zonas: costeira e costa-afora. Sendo assim, a presente dissertação teve o intuito de correlacionar os corpos de beachrocks que afloram em zona costeira aos que estão atualmente dispostos em zona costa-afora, próximo a isóbata de 25 m, levando em consideração seus aspectos petrográficos, diagenéticos e sedimentológicos. Para isso, foram percorridos cerca de 260 km de litoral, correspondendo ao trecho entre os municípios de Extremoz e Tibau, em busca de afloramentos de beachrocks. Seções colunares foram confeccionadas e amostras coletadas em estações de amostragem representativas da zona costeira, ao passo que da zona costa-afora apenas seções delgadas foram analisadas. Trabalhos disponíveis na literatura sobre o tema e área em pauta também foram utilizados. A partir dos dados levantados, observou-se que os beachrocks são formados por diferentes camadas ao longo de um perfil vertical. Estas camadas são claramente identificadas em afloramento pela diferença existente na composição, textura e estruturas sedimentares peculiares a cada uma delas. Seções delgadas foram confeccionadas e analisadas a partir de amostras coletadas nas diferentes camadas de diversos afloramentos. Um afloramento foi escolhido como afloramento modelo sendo este o de São Bento do Norte por apresentar a maior espessura de rocha aflorante (1,9 m). Este tem sido muito bem estudado tanto no corrente trabalho quanto em trabalhos de outros autores. A este foram comparados todos os outros afloramentos analisados. A partir da análise micropetrográfica, foram identificadas 03 microfácies para os beachrocks do Rio Grande do Norte, sendo elas: Quartzarenítica (< 2,9% de bioclastos), Quartzarenítica Bioclástica (entre 3 e 9,9% de bioclastos) e Bio-quartzarenítica (> 10% de bioclastos). Associando essas microfácies às análises sedimentológicas realizadas foi possível propor que as microfácies Quartzarenítica e Bio-quartzarenítica foram depositadas em zona de estirâncio enquanto que a microfácies Quartzarenítica Bioclástica foi depositada em zona de face litorânea superior. A história diagenética dos beachrocks estudados é marcada por quatro principais processos: compactação mecânica, cimentação, dissolução e geração de porosidade secundária, e oxidação. Dentre esses, o processo de cimentação é o mais importante, sendo caracterizado por precipitação de cimento de calcita rica em Mg sob cinco morfologias, a saber: cutículas criptocristalinas, franjas prismáticas isópacas, calcita espática microcristalina, calcita espática equante e agregados pseudo-peloidais. Todas estas morfologias foram formadas durante o estágio de eodiagênese, nas zonas freática marinha ativa ou freática meteórica ativa, corroborando assim com a idéia de que beachrocks têm sua litificação completa a pequenas profundidades. Associando as análises microfaciológicas às diagenéticas foi possível sugerir que a sucessão vertical de camadas vista em alguns beachrocks costeiros representam registros de variações de mais alta frequência do nível do mar durante o Holoceno. A partir daí, baseando-se em informações obtidas através de curvas de variação do nível do mar relativo no Holoceno para o Rio Grande do Norte, disponíveis na literatura, e na correlação aqui realizada entre os beachrocks costeiro e aqueles de zona costa-afora, foi possível inferir que estes últimos representam uma antiga linha de costa formada a idades relativas superiores a 7.000 anos A.P

analise da dispersao de ondas de superficie na provincia borborema, Nordeste do Brasil

The Borborema Province, Northeastern Brazil, had its internal structure investigated by different geophysical methods like gravity, magnetics and seismics. Additionally, many geological studies were also carried out to define the structural domains of this province. Despite the plethora of studies, there are still many important open aspects about its evolution. Here, we study the velocity structure of S-wave in the crust using dispersion of surface waves. The dispersion of surface waves allows an estimate of the average thickness of the crust across the region between the stations. The inversion of the velocity structure was carried out using the inter-station dispersion of surface waves of Rayleigh and Love types. The teleseismic events are mainly from the edges of the South and North American plates. The period of data collection occurred between 2007 and 2010 and we selected 7 events with magnitude above 5.0 MW and up to 40 km depth. The difference between the events back-azimuths and the interstation path was not greater than 10. We also know the depth of the Moho, results from Receiver Functions (Novo Barbosa, 2008), and use those as constrains in inversion. Even using different parameterizations of models for the inversion, our results were very similar the mean profiles velocity structure of S-wave. In pairs of stations located in the Cear´a Central Domain Borborema the province, there are ranges of depths for which the velocities of S are very close. Most of the results in the profile near the Moho complicate their interpretation at that depth, coinciding with the geology of the region, where there are many shear zones. In particular, the profile that have the route Potiguar Bacia in inter-station, had low velocities in the crust. We combine these results to the results of gravimetry and magnetometry (Oliveira, 2008) and receptor function (Novo Barbosa, 2008). We finally, the first results on the behavior of the velocity structure of S-wave with depth in the Province Borborema