Efeitos não-gaussianos em astrofísica e cosmologia

The recent astronomical observations indicate that the universe has null spatial curvature, is accelerating and its matter-energy content is composed by circa 30% of matter (baryons + dark matter) and 70% of dark energy, a relativistic component with negative pressure. However, in order to built more realistic models it is necessary to consider the evolution of small density perturbations for explaining the richness of observed structures in the scale of galaxies and clusters of galaxies. The structure formation process was pioneering described by Press and Schechter (PS) in 1974, by means of the galaxy cluster mass function. The PS formalism establishes a Gaussian distribution for the primordial density perturbation field. Besides a serious normalization problem, such an approach does not explain the recent cluster X-ray data, and it is also in disagreement with the most up-to-date computational simulations. In this thesis, we discuss several applications of the nonextensive q-statistics (non-Gaussian), proposed in 1988 by C. Tsallis, with special emphasis in the cosmological process of the large structure formation. Initially, we investigate the statistics of the primordial fluctuation field of the density contrast, since the most recent data from the Wilkinson Microwave Anisotropy Probe (WMAP) indicates a deviation from gaussianity. We assume that such deviations may be described by the nonextensive statistics, because it reduces to the Gaussian distribution in the limit of the free parameter q = 1, thereby allowing a direct comparison with the standard theory. We study its application for a galaxy cluster catalog based on the ROSAT All-Sky Survey (hereafter HIFLUGCS). We conclude that the standard Gaussian model applied to HIFLUGCS does not agree with the most recent data independently obtained by WMAP. Using the nonextensive statistics, we obtain values much more aligned with WMAP results. We also demonstrate that the Burr distribution corrects the normalization problem. The cluster mass function formalism was also investigated in the presence of the dark energy. In this case, constraints over several cosmic parameters was also obtained. The nonextensive statistics was implemented yet in 2 distinct problems: (i) the plasma probe and (ii) in the Bremsstrahlung radiation description (the primary radiation from X-ray clusters); a problem of considerable interest in astrophysics. In another line of development, by using supernova data and the gas mass fraction from galaxy clusters, we discuss a redshift variation of the equation of state parameter, by considering two distinct expansions. An interesting aspect of this work is that the results do not need a prior in the mass parameter, as usually occurs in analyzes involving only supernovae data.Finally, we obtain a new estimate of the Hubble parameter, through a joint analysis involving the Sunyaev-Zeldovich effect (SZE), the X-ray data from galaxy clusters and the baryon acoustic oscillations. We show that the degeneracy of the observational data with respect to the mass parameter is broken when the signature of the baryon acoustic oscillations as given by the Sloan Digital Sky Survey (SDSS) catalog is considered. Our analysis, based on the SZE/X-ray data for a sample of 25 galaxy clusters with triaxial morphology, yields a Hubble parameter in good agreement with the independent studies, provided by the Hubble Space Telescope project and the recent estimates of the WMAP

Ensino da astronomia no Brasil: educação formal, informal, não formal e divulgação científica

Este artigo deriva de uma pesquisa mais ampla sobre a educação em astronomia e a formação de professores, e apresenta um panorama geral sobre o tema em âmbito nacional. Procuramos gerar uma classificação das instituições e outras iniciativas brasileiras dedicadas à astronomia, levando em conta os seus objetivos, tais como o ensino formal, informal, não-formal, bem como aqueles destinados à popularização dessa ciência. Comenta-se, em forma de um breve ensaio, a importância da atuação contextualizada destas instâncias no ensino da astronomia, levantando um desafio ainda a ser considerado, referente ao estudo das possíveis relações entre estes estabelecimentos e iniciativas, visando o avanço da educação em astronomia, em um movimento contrário à dispersão e pulverização de atividades locais e pontuais dos mesmos. Argumentamos que a pesquisa em ensino de astronomia tem potencial para exercer este papel integrador.

A motivação e o significado do trabalho de bancários: estudo comparativo entre dois momentos do processo de reestruturação produtiva

This master s dissertation deals with motivation and the meaning of work amongst bank employees. This is done considering a cognitive perception. Work is understood here under a social and subjective comprehension, once it deals with significance attribution. Motivation is the process that rules choice of the different possibilities of individual behavior, all of which according to the Expectation Theory. This study aims to analyze the implications of the productive restructure, since it is related to technological innovation, organizational changes and management, in motivation and work significance. Thus, the objective of the research is to verify motivational differences and the meaning of work amongst bank employees. This is done in two distinct moments of the productive restructure of bank employees in Natal-RN. The research is divided in two parts. In the first one, changes that occurred in banks between 1999 until 2005 were identified by the means of interviews with 7 bank managers. The analyzed perspective was training intensifying, quality emphasis of customer attendance, the use of automation/technology, staff stabilization, change in staff profile, work intensification, etc. In the second study the Inventory of Motivation and Work Meaning was applied. Thus, questions related to work focus, social demographic data, in 187 bank employees were dealt with. The collected data was compared to data from previous work. It was observed that productive restructure has a reflection in the meaning of work increasing self-expression, economical reward, and responsibility in work conditions. All of the item mention beforehand maintain the level of inhumanness and consummation and respond as being the characteristics of the real work environment. On the other hand, bank employees value less justice, self-expression and more the survival perspective, implying instrumental values to work. As for motivation, it is increased among bank employees. These employees have greater expectations that their work produce results since they believe in their interference in work results

Dinâmica Costeira dos Campos petrolíferos Macau/Serra, litoral setentrional do Estado do Rio Grande do Norte

This thesis describes the general behavior of the northern shore of the State of Rio Grande do Norte relating beach profile morphology with hydrodynamic and sedimentological parameters. The Macau and Serra Oil Field are inserted on this area and are under accelerated coastal erosion. At these oil fields are installed oil wells from PETROBRAS, nowadays located directly in the shoreline, under constant attacks of coastal processes (e.g. waves, tides and currents), which promote an intense morphodynamic variability of this sandy coast. The area was monitored for 24 months in three different stations (P01, P02 and P03). The methodology applied involved current techniques of beach profiles, hydrodynamical processes, remote sensing and geophysics. A synthesis of results obtained through the use of different time scales (monthly, lunar cycle, seasonal, annual) from a coastal dynamics study is presented. The average wind direction corresponded to 77ºAz (NE). The steepness of the berm and of the shoreface, as well as coastal current direction, do not present major changes, with an average of 36º for the steepness of the berm, 15º for the shoreface and 15º for the coastal current direction. This data set allows us to infer that the months of larger coastal erosion were November/2000 and April/2001, because of the largest wave parameter during this time. The months of worse coastal erosion in this area are related with the increasing wavy energy. This in turn, seems to be related to seasonal climatic variations, with the wave energy and tide currents speed increasing during months of minor precipitations (June to January). The months of worse coastal erosion were September and November, when the largest wave parameters and speed currents are measured in the area. Since these months are included on the period of minor precipitations, we related the coastal erosion to seasonal climatic variations. The results obtained during these 24 months of monitoring confirms a situation of accentuated erosion, mainly in Profile 03 (Barra do Corta-Cachorro), where the wave height, period, and coastal current speed are always larger than the values found in Profile 02 (Macau5). Probably these values are more expressive in Profile 03, because it does not present any natural structure of protection against the wave impacts, as the barrier island located at Ponta do Tubarão, or the sand banks in front of Macau5. The transport of the sediments occurs from East to West, and the sand accumulation is more pronounced on Profile 03 intertidal zone, where there are embrionary dunes in dryer months. The tidal currents speed, on the other hand, is more accentuated in the Macau5 area (Profile 02). At Ponta do Tubarão, the tidal currents presented a preferential direction for NE, at times of flood, currents and for NW, at times of ebb current; at Barra do Corta-Cachorro the direction of the currents were predominantly for NW, independent of the tide phase, coinciding with the preferential direction of the longshore current. This currents inversion at Ponta do Tubarão is attributed to the presence of the Ponta do Tubarão island barrier and by the communication channel of the lagoon with the sea. The tide currents are better observed in protected areas, as in the Ponta do Tubarão, when they present inversion in their direction accordingly to the flood and ebb tide. In open areas, as in Barra do Corta-Cachorro, the tide currents are overprinted by the longshore currents. Sediment analysis does not show important modifications in grain size related to seasonality (dry- and rainy seasons). On the foreshore and backshore zones, the sediments vary from fine to medium sand, while in the shoreface they very from fine to very sands. The grains are mostly spheres, varying from sub rounded to sub angled. Quartz is the main component alongside Feldspat and heavy minerals as accessory components. Biogenic content is also present and mainly represented by mollusks fragments. The calculated sediment transport show values around 100 m3/day. The morphodynamic studies indicated that this is a reflexive area from October to April, and intermediate from May to September. The Relative Tide Range-RTR for this area is 4 < RTR < 15, and so classified in the mixed wave-tide group. Having this exposed we can affirm that the more active natural factors in this area are the currents, followed by the tides and the winds. The anthropic factors are exclusively local and punctual (Macau and Serra Oil Field). Taking in account the economic importance of the area, as well as the intensity of coastal processes acting on this shore, it is important a continuity of the monthly environmental monitoring looking for variations on longer-period cycles. These data have been stored on the geo-referenced database of the projects MARPETRO and PETRORISCO (REDE 05), aiming to model the coastal and sea environment, susceptible to oil spills and their derivatives

Efeitos de tempestades magnéticas em sinais de gps, em Natal, Brasil

Satellites signals present disturbances (scintillations), due to presence of irregularities in the ionospheric plasma. In the present work, we dedicate to the study of the attenuation of these scintillations that is, an improvement in the signal, during the main magnetic storm phase during the period of October 2006 to February 2007. Using amplitude of scintillation 1.5GHz (L1) data of the net of satellites GPS, in the ionospheric station of Natal (5.84o S, 35.20o O, -20o dip) and geomagnetic indices, during the minimum solar cycle (referred to as cycle 23), demonstrating its anti-correlation between magnetic activity (Kp) and index of scintillation () (Bonelli2005 method, that works for solar maximum, Bonelli(2005)). These results show that these storms correspond to category I of Aarons (1991). The magnetic storms can generate irregularities when the electric feld of penetration eastward on the pre-reversal hour intensificating that and can too generate irregularities on midnight and sunlight period. The limitation of the method applied here is that it is not considering some storms that had also occurred during equinox and summer in the Brazilian region. For this reason, we will use additional data of the stations of São João de Cariri (Imager and Photometer) and of the station at Fortaleza (Digissonde data), as aid to analyze these storms. The storms that had been left out by the applied method, fit in the other two categories of Aarons, with one only exception (storm of January, 02). We show that in the day of the main phase of the magnetic storm, and with presence of bubbles (according to data of the Imager and Photometer), the speed of vertical drift ~E ~B (hF=t) is below 20m/s, that is the threshold found for Anderson al., (2004) (>20m/s as condition favorable to the formation of irregularities and increase in the scintillation index). This reduction of the speed is due to solar minimum

Gravitomagnetismo e o teste da sonda gravidade B

The so-called gravitomagnetic field arised as an old conjecture that currents of matter (no charges) would produce gravitational effects similar to those produced by electric currents in electromagnetism. Hans Thirring in 1918, using the weak field approximation to the Einsteins field equations, deduced that a slowly rotating massive shell drags the inertial frames in the direction of its rotation. In the same year, Joseph Lense applied to astronomy the calculations of Thirring. Later, that effect came to be known as the Lense- Thirring effect. Along with the de Sitter effect, those phenomena were recently tested by a gyroscope in orbit around the Earth, as proposed by George E. Pugh in 1959 and Leonard I. Schiff in 1960. In this dissertation, we study the gravitational effects associated with the rotation of massive bodies in the light of the Einsteins General Theory of Relativity. With that finality, we develop the weak field approximation to General Relativity and obtain the various associated gravitational effects: gravitomagnetic time-delay, de Sitter effect (geodesic precession) and the Lense-Thirring effect (drag of inertial frames). We discus the measures of the Lense-Thirring effect done by LAGEOS Satellite (Laser Geodynamics Satellite) and the Gravity Probe B - GPB - mission. The GPB satellite was launched into orbit around the Earth at an altitude of 642 km by NASA in 2004. Results presented in May 2011 clearly show the existence of the Lense-Thirring effect- a drag of inertial frames of 37:2 7:2 mas/year (mas = milliarcsec)- and de Sitter effect - a geodesic precession of 6; 601:8 18:3 mas/year- measured with an accuracy of 19 % and of 0.28 % respectively (1 mas = 4:84810��9 radian). These results are in a good agreement with the General Relativity predictions of 41 mas/year for the Lense-Thirring effect and 6,606.1 mas/year for the de Sitter effect.

Caracterização morfológica e sedimentologica da plataforma, continental brasileira adjacente aos municípios de Fortim, Aracati e Icapuí- CE

The study area is located on the Brazilian Continental Shelf adjacent to Ceará State, inserted in the submerged Potiguar Basin. This area was submitted to extensional efforts during Upper Cretaceous, associated to the begining of the rifting that resulted in African and South American Continent separation. The main goal of this research was to better understand the sedimentary and geomorphological characteristics of the continental shelf adjacent to Fortim, Aracati and Icapuí (Ceará State). The used data base included geophysical (sides scan sonar and bathymetry studies) and sedimentological survey, associated to satellite image processing and interpretation. Inferences about suspended material and longshore drift was possible using satellite images, and differente bedforms were characterized such as: different kinds of dunes (longitudinal, cross and oblique), bioclastic banks, paleochannels, flat and rock bottom. The researched area comprehended about 2509,13 km2, where 6 different sedimentary facies, based on sediment composition and texture, could be recognized, such as: Bioclastic Sand, Siliciclastic Sand, Biosiliciclastic Sand, Bioclastic gravel, Biosiliciclastic sand with granule and gravel, and Silicibioclastic sand with granule and gravel. The integration of bathymetric, satellite image, side scan sonar and sedimentological data allow us a better characterization of this continental shelf area, as to advance in the knowledge of the continental shelf of the state of Ceara, a very important area to the oil industry because of its potential exploration and e exploitation, and to environmental survey as well

Isótopos de Nd na proveniência de rochas e sedimentos da bacia potiguar, ne do Brasil

Nd ISOTOPES IN THE PROVENANCE OF TERRIGENOUS AND CARBONATE ROCKS AND SEDIMENTS OF THE POTIGUAR BASIN, NORTHEASTERN BRAZIL. Mesozoic and Cenozoic rocks from the Potiguar Basin, including terrigenous and carbonate sediments have been investigated to identify their isotopic signature and source areas. Additionally, this study aims to determine the provenance of terrigenous and carbonate sediments on the Brazilian Continental shelf adjacent to Potiguar Basin. The Sm-Nd isotopic signatures of the rocks yielded model ages (TDM) in the range of 2,19- 2,88 Ga, indicating archean to paleoproterozoic sources from the basement. The terrigenous sediments yielded model ages (TDM) in the range of 2,31-2,26 Ga, from 17,5 to 0 cm depth. Despite the small number of samples, limited variations of provenance ages indicates the homogenization of the sediments, probably due to the strong influence of the basement, as the main source of sediments to the shelf. The Sm-Nd isotopic signatures of the carbonate sediments yielded model ages (TDM) in the range of 2,09-2,61 Ga, indicating archean to paleoproterozoic sources from the basement. The results also indicate that the shelf sediments are mainly derived from the Açu River or other small rivers from the Setentrional Sector of Rio Grande do Norte State. The littoral drift doesn´t seem to contribute with sediments from the Oriental Sector since isotopic signatures from this sector were not detected.

Dinâmica costeira entre as praias de Areia Preta e do Forte, Natal/RN

The coastal zone has been studied worldwide with a focus on the coastal erosion. In the present days, much of the world's coastlines are being affected by erosion, which causes great damage to the economy. This work had as study case the beaches of Areia Preta, Artistas, Meio and Forte located in Natal in Rio Grande do Norte. It shows as result the monitoring of the beach strip that makes possible to obtain quantitative and qualitative data, allows the study of the coastal dynamics of the beaches and the Recovery Project of the Areia Preta beach interference on adjacent beaches. This research was guided by the integrated analysis method on the systemic perspective. The pratical procedures adopted were: bibliographic research; fieldwork during eleven months (environmental characterization, collection of hydrodynamic data, topographic leveling, collection of sediments) and; sedimentological analysis of samples collected. By monitoring of the points A, B, C, D and E we were able to find the occurrence of the coastal erosion on their biggest part except by the C and D profiles. It was noted the need for the government to complete the hydraulic fill, as it made only 60% of the landfill planed. It was found that the spikes built on the beach of Areia Preta are preventing the natural transport of sediments that the longshore performs towards South-North. This interference is causing the lack of sediment on the beaches of Forte and Meio and their coastal erosion in consequence

Monitoramento da dinâmica costeira da praia de Ponta Negra

This dissertation includes the monitoring of coastal environmental dynamics at three points distinct from Ponta Negra beach, located on the South Coast of Natal, capital of Rio Grande do Norte, in the period June 2012 to May, 2013. For this, the following hypotheses were developed: Which actors morphodynamic and/or anthropogenic responsible for the changes in the study area? And yet, the configuration of the morphodynamic state of the beach, dissipative, reflective or intermediate? Faced with these questions , studies on the beach environment has its relevance as they may clarify the risks and responsibilities of anthropogenic intervention and also assist managers in more targeted action regarding the protection of praiais systems, since once committed, it is very difficult recover the environmental framework of the area, being greatly more feasible the development of multidisciplinary work plans that can guide human actions possible in search of an understanding to the harmonious interaction between society and the beach system. Its main goal is the understanding of the processes of coastal dynamics, methodological procedures that supported the implementation of this research were based on the object of study related literature associated with the collection of data resulting from beach profiles made monthly in spring tides (full moon), the hydrodynamic data and statistical quantification data (%) and size classification of sediment sediment after laboratory analysis. The results obtained from annual comparative tables of beach profiles, associated sedimentological analysis, indicated a positive sediment budget, tending to equilibrium for Point 01 and Point 02 negative. Have to Step 03 were added to the hydrodynamic data, which allowed also on a comparative framework, the perception of a depositional dynamics, with a tendency to decrease the accumulation of material at the end of the annual cycle. These data also allowed for the point 03, the calculation of the volume of material transported by the longshore current was around 104.280 m³/m, plus the Dean parameter which established a morphological state of the dissipative beach with specific prevalences for point 03. Thus, given the results presented in this work in a timely monitoring of coastal dynamics is expected that managers and public authorities can articulate multidisciplinary work plans, always aiming actions that seek understanding and effective commitment to the recovery of the harmonious interaction between society and Ponta Negra beach environment

Paisagem arquitetônica da cidade de João Pessoa/PB e seus significados: o perceptivo dos moradores

This study was conducted in the city of João Pessoa, Paraíba mesoregion Forest. Having to analyze how does the appreciation of the architectural heritage to the visitor and pessoense Capital Paraiba, taking into account the narratives of João Pessoa, and practitioners of foreign tourists of cultural tourism. This research builds on a theoretical foundation on concepts of landscape and place. Was taken as a foundation to Cultural Geography. The research in question is justified by embarking on Geography and Heritage and cast a glance on the geographical cultural landscape, trying to unravel the symbols assigned to the ancient architectural examples, meaning that interfere with power relationships that cross generations, constructing and deconstructing identities, is dispersed or integrating cultures, creating cultural groups and social conflict. It is concluded that the geographical area derives from a number of factors, among them the culture and this in turn will shaping the landscape, reflecting the abstract over the concrete architecture of the oldest to the most current, turning from the material to the immaterial in World Heritage Site

Temporary fragmentation of a marginal lake and its effects on zooplankton community structure and organization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Absorção de Subdoses Glyphosate aplicadas em diferentes locais de plantas de eucalipto

Um dos grandes problemas enfrentados em áreas de reflorestamento com o cultivo de eucalipto são as plantas daninhas, cujo manejo assume papel de destaque entre os tratos culturais e com reflexos diretos no rendimento e nos custos de produção. Trabalhos preliminares de pesquisa e observação de campo apontam para uma tolerância diferencial ao glyphosate entre os locais (folhas e caule) que este herbicida atinge. Nesse contexto, este trabalho teve como objetivo verificar a intoxicação e o desenvolvimento de plantas submetidas a subdoses de glyphosate e sua absorção em diferentes locais de aplicação na planta, simulando uma deriva. O experimento foi conduzido em casa de vegetação, em um esquema fatorial, sendo quatro subdoses de glyphosate (40; 80; 160 e 240 g ha-1) e três locais de aplicação (folha, caule e da planta inteira), além de uma testemunha sem a aplicação de herbicidas. O herbicida glyphosate causou fitointoxicação à cultura do eucalipto, sendo crescente com o aumento das subdoses e com maior intensidade nas aplicações sobre o caule e a planta inteira, atingindo 75% aos 14 dias após aplicação. O ganho em altura de plantas e em diâmetro, em massa seca da parte aérea e da área foliar teve reduções significativas, que resultaram em perdas de até 58% na massa seca, 56% na área foliar e uma diferença de 6 cm no ganho em altura.

Fatores qualitativos da ponta de energia hidráulica ADGA 110015 para pulverização agrícola

Este trabalho teve o objetivo de caracterizar o diâmetro e a uniformidade das gotas e o perfil de distribuição volumétrica da ponta denominada antideriva de grande ângulo (ADGA) 110015, nas pressões de 207 e 310 kPa, para determinar o seu espaçamento na barra de pulverização. Os perfis de distribuição volumétrica para a altura de 50 cm foram avaliados em mesa de deposição. A partir dos perfis de distribuição, simulou-se o padrão de deposição ao longo da barra de pulverização. O espectro do diâmetro de gotas foi determinado em analisador de tamanho de partículas por difração laser. Pode-se concluir que a ponta ADGA 110015 apresentou perfil de distribuição do jato simétrico nas pressões de trabalho de 207 e 310 kPa. Na maior pressão, pode-se operar com menor altura da barra ou com as pontas mais espaçadas entre si, pois o maior ângulo de aspersão do jato resultou em diminuição do coeficiente de variação. Entretanto, o aumento da pressão proporcionou redução significativa no diâmetro das gotas, aumentando o potencial de cobertura do alvo, a suscetibilidade à deriva e à evaporação.

Espectro de gotas de pontas de pulverização com adjuvantes de uso agrícola

O sucesso de uma boa aplicação de produtos fitossanitários depende da sinergia entre fatores como tamanho de gota, tipo de ponta, pressão, volume e composição da calda e características do alvo. Assim, o objetivo deste trabalho foi avaliar o espectro de gotas produzidas por pontas de jato plano defletor (TT 11002) e jato plano defletor com indução de ar (TTI 11002), com diferentes adjuvantes adicionados à calda de pulverização, pela técnica de difração de raio laser. O experimento foi conduzido em delineamento inteiramente casualizado, com quatro repetições, em esquema fatorial 2 x 5, ou seja, duas pontas de aplicação (jato plano defletor e jato plano defletor com indução de ar) e cinco composições de calda (água e água mais quatro adjuvantes: fosfatidilcoline+ácido propiônico, éter poliglicólico de monilfenol, ésteres de ácidos graxos e nonil-fenol etoxilado+óxido de etileno). em ambiente controlado, avaliou-se o espectro de gotas, por meio de um analisador a laser de gotas em tempo real, na pressão de 276 kPa. O efeito dos adjuvantes no espectro de gotas mostrou-se dependente da ponta de pulverização empregada. A adição dos adjuvantes à calda não alterou o risco potencial de deriva, expresso pela porcentagem do volume em gotas com diâmetro inferior a 100 µm, porém o adjuvante fosfatidilcoline+ácido propiônico reduziu o diâmetro da mediana volumétrica das gotas produzidas pela ponta de jato plano defletor com indução de ar, em relação à avaliação feita somente com água.