998 resultados para Rockets (Aeronautics)


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The dynamical processes that lead to open cluster disruption cause its mass to decrease. To investigate such processes from the observational point of view, it is important to identify open cluster remnants (OCRs), which are intrinsically poorly populated. Due to their nature, distinguishing them from field star fluctuations is still an unresolved issue. In this work, we developed a statistical diagnostic tool to distinguish poorly populated star concentrations from background field fluctuations. We use 2MASS photometry to explore one of the conditions required for a stellar group to be a physical group: to produce distinct sequences in a colour-magnitude diagram (CMD). We use automated tools to (i) derive the limiting radius; (ii) decontaminate the field and assign membership probabilities; (iii) fit isochrones; and (iv) compare object and field CMDs, considering the isochrone solution, in order to verify the similarity. If the object cannot be statistically considered as a field fluctuation, we derive its probable age, distance modulus, reddening and uncertainties in a self-consistent way. As a test, we apply the tool to open clusters and comparison fields. Finally, we study the OCR candidates DoDz 6, NGC 272, ESO 435 SC48 and ESO 325 SC15. The tool is optimized to treat these low-statistic objects and to separate the best OCR candidates for studies on kinematics and chemical composition. The study of the possible OCRs will certainly provide a deep understanding of OCR properties and constraints for theoretical models, including insights into the evolution of open clusters and dissolution rates.

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FS CMa type stars are a recently described group of objects with the B[e] phenomenon which exhibits strong emission-line spectra and strong IR excesses. In this paper, we report the first attempt for a detailed modeling of IRAS 00470+6429, for which we have the best set of observations. Our modeling is based on two key assumptions: the star has a main-sequence luminosity for its spectral type (B2) and the circumstellar (CS) envelope is bimodal, composed of a slowly outflowing disklike wind and a fast polar wind. Both outflows are assumed to be purely radial. We adopt a novel approach to describe the dust formation site in the wind that employs timescale arguments for grain condensation and a self-consistent solution for the dust destruction surface. With the above assumptions we were able to satisfactorily reproduce many observational properties of IRAS 00470+6429, including the Hi line profiles and the overall shape of the spectral energy distribution. Our adopted recipe for dust formation proved successful in reproducing the correct amount of dust formed in the CS envelope. Possible shortcomings of our model, as well as suggestions for future improvements, are discussed.

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We report the first simultaneous zJHK spectroscopy on the archetypical Seyfert 2 galaxy NGC 1068 covering the wavelength region 0.9-2.4 mu m. The slit, aligned in the north-south direction and centred in the optical nucleus, maps a region 300 pc in radius at subarcsec resolution, with a spectral resolving power of 360 km s-1. This configuration allows us to study the physical properties of the nuclear gas including that of the north side of the ionization cone, map the strong excess of continuum emission in the K band and attributed to dust and study the variations, both in flux and profile, in the emission lines. Our results show the following. (1) Mid- to low-ionization emission lines are split into two components, whose relative strengths vary with the position along the slit and seem to be correlated with the jet. (2) The coronal lines are single-peaked and are detected only in the central few hundred of pc from the nucleus. (3) The absorption lines indicate the presence of intermediate age stellar population, which might be a significant contributor to the continuum in the near-IR spectra. (4) Through some simple photoionization models we find photoionization as the main mechanism powering the emitting gas. (5) Calculations using stellar features point to a mass concentration inside the 100-200 pc of about 1010 M(circle dot).

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We performed stellar population synthesis on the nuclear and extended regions of NGC 1068 by means of near-infrared spectroscopy to disentangle their spectral energy distribution components. This is the first time that such a technique is applied to the whole 0.8-2.4 mu m wavelength interval in this galaxy. NGC 1068 is one of the nearest and probably the most studied Seyfert 2 galaxy, becoming an excellent laboratory to study the interaction between black holes, the jets that they can produce and the medium in which they propagate. Our main result is that traces of young stellar population are found at similar to 100 pc south of the nucleus. The contribution of a power-law continuum in the centre is about 25 per cent, which is expected if the light is scattered from a Seyfert 1 nucleus. We find peaks in the contribution of the featureless continuum about 100-150 pc from the nucleus on both sides. They might be associated with regions where the jet encounters dense clouds. Further support to this scenario is given by the peaks of hot dust distribution found around these same regions and the H(2) emission-line profile, leading us to propose that the peaks might be associated to regions where stars are being formed. Hot dust also has an important contribution to the nuclear region, reinforcing the idea of the presence of a dense, circumnuclear torus in this galaxy. Cold dust appears mostly in the south direction, which supports the view that the south-west emission is behind the plane of the galaxy and is extinguished very likely by dust in the plane. Intermediate-age stellar population contributes significantly to the continuum, especially in the inner 200 pc.

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A numerous population of weak line galaxies (WLGs) is often left out of statistical studies on emission-line galaxies (ELGs) due to the absence of an adequate classification scheme, since classical diagnostic diagrams, such as [O iii]/H beta versus [N ii]/H alpha (the BPT diagram), require the measurement of at least four emission lines. This paper aims to remedy this situation by transposing the usual divisory lines between star-forming (SF) galaxies and active galactic nuclei (AGN) hosts and between Seyferts and LINERs to diagrams that are more economical in terms of line quality requirements. By doing this, we rescue from the classification limbo a substantial number of sources and modify the global census of ELGs. More specifically, (1) we use the Sloan Digital Sky Survey Data Release 7 to constitute a suitable sample of 280 000 ELGs, one-third of which are WLGs. (2) Galaxies with strong emission lines are classified using the widely applied criteria of Kewley et al., Kauffmann et al. and Stasinska et al. to distinguish SF galaxies and AGN hosts and Kewley et al. to distinguish Seyferts from LINERs. (3) We transpose these classification schemes to alternative diagrams keeping [N ii]/H alpha as a horizontal axis, but replacing H beta by a stronger line (H alpha or [O ii]), or substituting the ionization-level sensitive [O iii]/H beta ratio with the equivalent width of H alpha (W(H alpha)). Optimized equations for the transposed divisory lines are provided. (4) We show that nothing significant is lost in the translation, but that the new diagrams allow one to classify up to 50 per cent more ELGs. (5) Introducing WLGs in the census of galaxies in the local Universe increases the proportion of metal-rich SF galaxies and especially LINERs. In the course of this analysis, we were led to make the following points. (i) The Kewley et al. BPT line for galaxy classification is generally ill-used. (ii) Replacing [O iii]/H beta by W(H alpha) in the classification introduces a change in the philosophy of the distinction between LINERs and Seyferts, but not in its results. Because the W(H alpha) versus [N ii]/H alpha diagram can be applied to the largest sample of ELGs without loss of discriminating power between Seyferts and LINERs, we recommend its use in further studies. (iii) The dichotomy between Seyferts and LINERs is washed out by WLGs in the BPT plane, but it subsists in other diagnostic diagrams. This suggests that the right wing in the BPT diagram is indeed populated by at least two classes, tentatively identified with bona fide AGN and `retired` galaxies that have stopped forming stars and are ionized by their old stellar populations.

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FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003-2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li I 6708 angstrom line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral-type primary companion of a luminosity log L/L(circle dot) = 3.9 +/- 0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0 +/- 0.3 kpc from the Sun.

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We present a comprehensive analysis of the spatial, kinematic and chemical properties of stars and globular clusters (GCs) in the `ordinary` elliptical galaxy NGC 4494 using data from the Keck and Subaru telescopes. We derive galaxy surface brightness and colour profiles out to large galactocentric radii. We compare the latter to metallicities derived using the near-infrared Calcium Triplet. We obtain stellar kinematics out to similar to 3.5 effective radii. The latter appear flattened or elongated beyond similar to 1.8 effective radii in contrast to the relatively round photometric isophotes. In fact, NGC 4494 may be a flattened galaxy, possibly even an S0, seen at an inclination of similar to 45 degrees. We publish a catalogue of 431 GC candidates brighter than i(0) = 24 based on the photometry, of which 109 are confirmed spectroscopically and 54 have measured spectroscopic metallicities. We also report the discovery of three spectroscopically confirmed ultra-compact dwarfs around NGC 4494 with measured metallicities of -0.4 less than or similar to [Fe/H] less than or similar to -0.3. Based on their properties, we conclude that they are simply bright GCs. The metal-poor GCs are found to be rotating with similar amplitude as the galaxy stars, while the metal-rich GCs show marginal rotation. We supplement our analysis with available literature data and results. Using model predictions of galaxy formation, and a suite of merger simulations, we find that many of the observational properties of NGC 4494 may be explained by formation in a relatively recent gas-rich major merger. Complete studies of individual galaxies incorporating a range of observational avenues and methods such as the one presented here will be an invaluable tool for constraining the fine details of galaxy formation models, especially at large galactocentric radii.

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We describe a new spectroscopic technique for measuring radial metallicity gradients out to large galactocentric radii. We use the DEep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck telescope and the galaxy spectrum extraction technique of Proctor et al. We also make use of the metallicity sensitive near-infrared Calcium ii triplet (CaT) features together with single stellar population models to obtain metallicities. Our technique is applied as a pilot study to a sample of three relatively nearby (< 30 Mpc) intermediate-mass to massive early-type galaxies. Results are compared with previous literature inner region values and generally show good agreement. We also include a comparison with profiles from dissipational disc-disc major merger simulations. Based on our new extended metallicity gradients combined with other observational evidence and theoretical predictions, we discuss possible formation scenarios for the galaxies in our sample. The limitations of our new technique are also discussed.

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The highest energy cosmic ray event reported by the Auger Observatory has an energy of 148 EeV. It does not correlate with any nearby (z<0.024) object capable of originating such a high energy event. Intrigued by the fact that the highest energy event ever recorded (by the Fly`s Eye collaboration) points to a faraway quasar with very high radio luminosity and large Faraday rotation measurement, we have searched for a similar source for the Auger event. We find that the Auger highest energy event points to a quasar with similar characteristics to the one correlated to the Fly`s Eye event. We also find the same kind of correlation for one of the highest energy AGASA events. We conclude that so far these types of quasars are the best source candidates for both Auger and Fly`s Eye highest energy events. We discuss a few exotic candidates that could reach us from gigaparsec distances.

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O projeto de pesquisa pretende analisar a história da criação das organizações que deram origem à Embraer, isto é, o Ministério da Aeronáutica, o Centro Tecnológico da Aeronáutica e o Instituto Tecnológico da Aeronáutica, fundados nos anos quarenta e cinqüenta. Estas organizações criaram as condições para a fundação da empresa estatal em 1969. Serão analisadas as relações dessas organizações com o projeto estratégico de defesa nacional da Aeronática nesse período.

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Esta tese aborda a identificação e análise das relações causais de incidentes (acidentes e quaseacidentes) no ato anestésico, em salas cirúrgicas, considerando os aspectos humanos, técnicos e organizacio nais envolvidos. Inicialmente, realizou-se revisão sistemática em estudos de casos (no Brasil e Estados Unidos da América - USA), sendo seu modelo descritivo, a direcionalidade retrógrada e o sentido temporal histórico. Procurou-se analisar e sintetizar as evidências sobre incidentes, onde foram identificadas oportunidades de melhorias nos modelos utilizados. A seguir, foram conduzidas pesquisas quali-quantitativas com questionários validados, cujos dados puderam revelar a existência de condutas sistemáticas conduzindo a desfechos desfavoráveis. A última etapa foi a aplicação de questionário adaptado da técnica NASA/TLX (National Aeronautics and Space Adiministration/Task Load) para avaliar o nível da carga de trabalho percebido pelos anestesiologistas durante a realização do ato anestésico. Dos resultados obtidos pôde-se constatar que 81,7% dos anestesiologistas têm a percepção que para ser um bom anestesiologista é necessário dar segurança aos pacientes. Dos estudos de casos de incidentes no ato anestésico, onde nos relatos são atribuídos 100% de falhas técnicas do dispositivo médico, os resultados refutaram esse dado e indicaram que 87,5% (Food and Drug Administration - FDA/USA), 66,7% (Sociedade Brasileira de Anestesiologia - SBA/BRASIL) e 94% (Estudo Exploratório - EE/BRASIL) foram falhas organizacionais. Identificou-se, na amostra estudada, que 50% (FDA), 58,8% (EE), 44,4% (SBA) das falhas humanas foram relacionadas a pouca familiaridade do anestesiologista com as tecnologias (dispositivo médico), ou seja , são problemas com a calibração do conhecimento. Os resultados mais significativos em relação à conseqüência dos incidentes foram: 6,3% (quase-acidentes) e 16,5% (acidentes) foram a óbito, 11,4% (quase-acidentes) e 17,7% (acidentes) sofreram seqüelas permanentes, 31,6% (quase-acidentes) e 46,8% (acidentes) sofreram internação prolongada. O fator de prevenção que mais se destacou foi a maior vigilância e constatouse que os anestesiologistas acreditam que 63,4% dos quase-acidentes e 50,7% dos acidentes podem ser evitados. Os modelos mentais pré-estabelecidos para análise de falhas em incidentes no ato anestésico que consideram apenas o fator humano-máquina não são mais suficientes, estes são sintomas de grandes problemas do sistema organizacional e, se não forem valorizados e analisados, podem realizar seu potencial.

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O objetivo desta dissertação é constatar o nível de relacionamento entre civis e militares, antes e depois da criação do Ministério da Defesa, em 1999. Inicialmente descreve-se sobre o surgimento de cada Força Armada e verifica-se que Marinha do Brasil e Exército Brasileiro, nos anos 1820, foram criados por necessidade de segurança e defesa ao País, mas obtidas por iniciativa e vontade do povo. A Aeronáutica, nos 1940, originou-se da junção dos segmentos aeronáuticos da Marinha e do Exército. Constata-se que a sociedade não se envolve, como deveria, nas questões de segurança e defesa nacionais, muito menos durante e após o período dos Governos Militares. Percebe-se que esta apatia, por parte da sociedade, com o tema tem várias explicações. Há falta de informações sobre o assunto. Passados mais de vinte anos de os Governos Militares, a ferida ainda custa para ser cicatrizada e o estreitamento desejado, entre civis e militares, é questão a ser estudada. Após a criação do Ministério da Defesa, constatou-se que, de alguma forma, houve aproximação entre civis e militares. Inclusive na troca de conhecimentos. Houve conferências, simpósios, encontros, reuniões sobre as questões de defesa, e documentos de alto nível foram estudados e elaborados por civis e militares. A revisão da Política de Defesa Nacional, a elaboração da Estratégia Nacional de Defesa e os estudos para a confecção do Livro Branco de Defesa Nacional são exemplos que confirmam esta aproximação. Antes da existência do Ministério da Defesa isso não acontecia. O presente estudo objetiva avaliar a criação do Ministério da Defesa como possível ponto de inflexão na participação da sociedade nos assuntos de Defesa e a aproximação entre civis e militares.

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Sugarcane (Saccharum spp.) is a plant from Poaceae family that has an impressive ability to accumulate sucrose in the stalk, making it a significant component of the economy of many countries. About 100 countries produce sugarcane in an area of 22 million hectares worldwide. For this reason, many studies have been done using sugarcane as a plant model in order to improve production. A change in gravity may be one kind of abiotic stress, since it generates rapid responses after stimulation. In this work we decided to investigate the possible morphophysiological, biochemical and molecular changes resulting from microgravity. Here, we present the contributions of an experiment where sugarcane plants were submitted to microgravity flight using a vehicle VSB-30, a sounding rocket developed by Aeronautics and Space Institute teams, in cooperation with the German Space Agency. Sugarcane plants with 10 days older were submitted to a period of six minutes of microgravity using the VSB-30 rocket. The morphophysiological analyses of roots and leaves showed that plants submitted to the flight showed changes in the conduction tissues, irregular pattern of arrangement of vascular bundles and thickening of the cell walls, among other anatomical changes that indicate that the morphology of the plants was substantially influenced by gravitational stimulation, besides the accumulation of hydrogen peroxide, an important signaling molecule in stress conditions. We carried out RNA extraction and sequencing using Illumina platform. Plants subjected to microgravity also showed changes in enzyme activity. It was observed an increased in superoxide dismutase activity in leaves and a decreased in its activity in roots as well as for ascorbate peroxidase activity. Thus, it was concluded that the changes in gravity were perceived by plants, and that microgravity environment triggered changes associated with a reactive oxygen specie signaling process. This work has helped the understanding of how the gravity affects the structural organization of the plants, by comparing the anatomy of plants subjected to microgravity and plants grown in 1g gravity

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The subject of this research is the spiritual religious field, connected with the local cultural perspectives. Its basis is the analysis of two spiritual groups settled in Natal/RN: The Spiritual Group Evangelho no Lar and the Spiritual Center Garimpeiros da Luz . These two groups represent a point of convergence of several sectors of this religion, either through its insertion in the local sphere or in contact to nationally influent leaders, like the mediums Francisco Cândido Xavier and Divaldo Pereira Franco. Then, it aims to reach the potiguar singularities in their spiritualism approaches, looking for an analyses to possible connections between local values and themes from the spiritualism largely developed in Brazil. So, its objective is to act in the scope of influence, references, representations and adaptive practices in a local context, and they signalize special practices . The approaches until now developed refer only to the living of a Brazilian spiritualism, perfectly developed in contact with the catholic substrate, but there s still a gap about the local observation, with its peculiarities, which its research aims to disclosure. The option for a qualitative approach, in perfect relationship with the nature of the questions which were made was considered as an appropriate way to guide the study. To reach this, it will be made an ethnography of the studied groups, not only in the use of open interviews with its members but also in the contact and observation of its religious behavior, for example: meeting for studies of the doctrine, mediunic meetings, public lectures, helping the public in general. As results of this research we can point to the delimitation of local cultural references, which are undeniable, in relation to the identification of RN personalities who are considered coordinators or active spirits in the work performed by the groups. Thus, Auta de Souza, poetess and woman of great religiosity, Augusto Severo de Albuquerque Maranhão, martyr of the aeronautics, Father João Maria, object of popular devotion and Abdias Antônio de Oliveira, ex president of the Spiritual Federation of RN, present themselves as spiritual beings who lead the adaptability to the local context. In such a context, we have to point out the work of mediums, who, having a specific charisma, interacted with the groups in the establishment of these cultural bridges already made in their own contexts (national level), through the work equally possible to be locally reproduced. This and other facts, point out to perspectives of cultural circularity , including referring to a greater linking to sub layers in a true zone that converges and has circulation between an erudite spiritualism with another one, turned to the incorporation of local and popular elements

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This work presents the development of new microwaves structures, filters and high gain antenna, through the cascading of frequency selective surfaces, which uses fractals Dürer and Minkowski patches as elements, addition of an element obtained from the combination of the other two simple the cross dipole and the square spiral. Frequency selective surfaces (FSS) includes a large area of Telecommunications and have been widely used due to its low cost, low weight and ability to integrate with others microwaves circuits. They re especially important in several applications, such as airplane, antennas systems, radomes, rockets, missiles, etc. FSS applications in high frequency ranges have been investigated, as well as applications of cascading structures or multi-layer, and active FSS. In this work, we present results for simulated and measured transmission characteristics of cascaded structures (multilayer), aiming to investigate the behavior of the operation in terms of bandwidth, one of the major problems presented by frequency selective surfaces. Comparisons are made with simulated results, obtained using commercial software such as Ansoft DesignerTM v3 and measured results in the laboratory. Finally, some suggestions are presented for future works on this subject