Página 9 dos resultados de 178 itens digitais encontrados em 0.001 segundos

Carta enviada pelo Conde de Nioac para o conselheiro João Alfredo Correia de Oliveira

Nioac, Conde de
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Correspondencia Formato: 7 p.
Português
Relevância na Pesquisa
16.53%
¹Oiapoque (questão de fronteira).G21; Os jornais vão chegando com as notícias do entusiasmo em todo o Brasil pela extinção da escravidão, deixando o Imperador muito alegre, se dizendo feliz porque tudo se tenha "feito com tanta sabedoria e sem e sem o menor abalo". Fornece informações sobre a convalescença de S.M. e remete (anexo) o original do laudo médico do mal que o acometera, estando firmado pelos médicos Mota Maia, Semmola, Charcot e Bruno de Geovanni. Faz demoradas considerações sobre o temperamento agitado de D. Pedro II remete (anexa) cópia do próprio Pinha de um telegrama do rei Humberto da Itália e diz que S.M. manifestou desejos de que a questão do Oiapoque¹ fosse devolvida por arbitragem escolhendo-se o rei dos belgas e o Presidente Cleveland para a referida. Conclui pedindo ao conselheiro que "tome cuidado com a saúde pelo amor de Deus".

Time-dependent modelling of pulsar wind nebulae

Vorster, M. J.; Tibolla, O.; Ferreira, S. E. S.; Kaufmann, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/08/2013 Português
Relevância na Pesquisa
16.53%
A spatially-independent model that can be used to calculate the temporal evolution of the electron/ positron spectrum in a spherically expanding pulsar wind nebula is presented. The model is applied to the young nebula G21.5-0.9, as well as to the unidentified TeV sources HESS J1427-608 and HESS J1507-622. The parameters derived from the model strengthens the idea that the unidentified sources can be identified as evolved pulsar wind nebulae.; Comment: ICRC 2013 proceedings paper

In-orbit calibration of vignetting in XMM-Newton EPIC

Lumb, D. H.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/03/2002 Português
Relevância na Pesquisa
16.53%
We briefly describe the in orbit measurements of the mirror vignetting, using observations of SNR G21.5-09. The instrument features which complicate these measurements are briefly described, and we show the spatial and energy dependences, outlining assumptions made in deriving the eventual agreement between theory and measurement.; Comment: 4 pages, 6 figures. Submitted to proceedings of "New Visions of the X-ray Universe", held ESTEC, Noordwijk, Netherlands Nov 2001

On exact solutions of the equation for a pion in external fields III

Kruglov, S. I.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/08/1999 Português
Relevância na Pesquisa
16.53%
The exact solutions of the equation for a composite scalar particle which possesses electric and magnetic polarizabilities are found in an external uniform static magnetic field parallel to the direction of propagation of the quantized electromagnetic wave. As a particular case, the relativistic coherent states of a particle in the field of photons were considered. When the average photon number trends to infinity, the solution tends to the solution corresponding to the external classical electromagnetic wave with circular polarization.; Comment: 16 pages; The first two parts where published in 1) Proc.of XVI Int'l Warsaw Meeting, Kazimierz, 1993, ed. by Z.Ajduk et al.-W.S.,Singapore, p.477-480, and 2) J.Phys.G21 (1995) 1643

Time-dependent Modeling of Pulsar Wind Nebulae

Vorster, M. J.; Tibolla, O.; Ferreira, S. E. S.; Kaufmann, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/09/2013 Português
Relevância na Pesquisa
16.53%
A spatially independent model that calculates the time evolution of the electron spectrum in a spherically expanding pulsar wind nebula (PWN) is presented, allowing one to make broadband predictions for the PWN's non-thermal radiation. The source spectrum of electrons injected at the termination shock of the PWN is chosen to be a broken power law. In contrast to previous PWN models of a similar nature, the source spectrum has a discontinuity in intensity at the transition between the low and high-energy components. To test the model, it is applied to the young PWN G21.5--0.9, where it is found that a discontinuous source spectrum can model the emission at all wavelengths better than a continuous one. The model is also applied to the unidentified sources HESS J1427--608 and HESS J1507--622. Parameters are derived for these two candidate nebulae that are consistent with the values predicted for other PWNe. For HESS J1427--608 a present-day magnetic field of $B\s{age}=0.4\,\mu\text{G}$ is derived. As a result of the small present-day magnetic field, this source has a low synchrotron luminosity, while remaining bright at GeV/TeV energies. It is therefore possible to interpret HESS J1427--608 within the ancient PWN scenario. For the second candidate PWN HESS J1507--622...

New Companions for the lonely Crab? VHE emission from young pulsar wind nebulae revealed by H.E.S.S

Collaboration, H. E. S. S.; :; Djannati-Atai, A.; De Jager, O. C.; Terrier, R.; Gallant, Y. A.; Hoppe, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/10/2007 Português
Relevância na Pesquisa
16.53%
The deeper and more extended survey of the central parts of the Galactic Plane by H.E.S.S. during 2005-2007 has revealed a number of new point-like, as well as, extended sources. Two point-like sources can be associated to two remarkable objects around "Crab-like" young and energetic pulsars in our Galaxy: G21.5-0.9 and Kes 75. The characteristics of each of the sources are presented and possible interpretations are briefly discussed.; Comment: 4 pages, for figures; To appear in the Proceedings of the 30th ICRC (Merida, Mexico)

Observations of four glitches in the young pulsar J1833-1034 and study of its glitch activity

Roy, Jayanta; Gupta, Yashwant; Lewandowski, Wojciech
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/05/2012 Português
Relevância na Pesquisa
16.53%
We present the results from timing observations with the GMRT of the young pulsar J1833-1034, in the galactic supernova remnant G21.5-0.9. We detect the presence of 4 glitches in this pulsar over a period of 5.5 years, making it one of a set of pulsars that show fairly frequent glitches. The glitch amplitudes, characterized by the fractional change of the rotational frequency, range from 1 \times 10^-9 to 7 \times 10^-9, with no evidence for any appreciable relaxation of the rotational frequency after the glitches. The fractional changes observed in the frequency derivative are of the order of 10-5 . We show conclusively that, in spite of having significant timing noise, the sudden irregularities like glitches detected in this pulsar can not be modeled as smooth timing noise. Our timing solution also provides a stable estimate of the second derivative of the pulsar spin-down model, and a plausible value for the braking index of 1.857, which, like the value for other such young pulsars, is much less than the canonical value of 3.0. PSR J1833-1034 appears to belong to a class of pulsars exhibiting fairly frequent occurrence of low amplitude glitches. This is further supported by an estimate of the glitch activity parameter, Ag = 1.53 \times 10^-15 s^-2...

HI in four star-forming low-luminosity E/S0 and S0 galaxies

Sadler, E.; Oosterloo, T.; Morganti, R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/10/1999 Português
Relevância na Pesquisa
16.53%
We present HI data cubes of four low-luminosity early-type galaxies which are currently forming stars. These galaxies have absolute magnitudes in the range M_B=-17.9 to -19.9 (H_o=50 km/s/Mpc). Their HI masses range between a few times 10^8 and a few times 10^9 M_sun and the corresponding values for M_HI/L_B are between 0.07 and 0.42, so these systems are HI rich for their morphological type. In all four galaxies, the HI is strongly centrally concentrated with high central HI surface densities, in contrast to what is typically observed in more luminous early-type galaxies. In two galaxies (NGC 802 and ESO 118-G34), the kinematics of the HI suggests that the gas is in a strongly warped disk, which we take as evidence for recent accretion of HI. In the other two galaxies (NGC 2328 and ESO 027-G21) the HI must have been part of the systems for a considerable time. The HI properties of low-luminosity early-type galaxies appear to be systematically different from those of many more luminous early-type galaxies, and we suggest that these differences are due to a different evolution of the two classes. The star formation history of these galaxies remains unclear. Their UBV colours and Halpha emission-line strengths are consistent with having formed stars at a slowly-declining rate for most of the past 10^10 years. However...

In-orbit Vignetting Calibrations of XMM-Newton Telescopes

Lumb, D. H.; Finoguenov, A; Saxton, R; Aschenbach, B; Gondoin, P.; Kirsch, M; Stewart, I. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/03/2004 Português
Relevância na Pesquisa
16.53%
We describe measurements of the mirror vignetting in the XMM-Newton Observatory made in-orbit, using observations of SNR G21.5-09 and SNR 3C58 with the EPIC imaging cameras. The instrument features that complicate these measurements are briefly described. We show the spatial and energy dependences of measured vignetting, outlining assumptions made in deriving the eventual agreement between simulation and measurement. Alternate methods to confirm these are described, including an assessment of source elongation with off-axis angle, the surface brightness distribution of the diffuse X-ray background, and the consistency of Coma cluster emission at different position angles. A synthesis of these measurements leads to a change in the XMM calibration data base, for the optical axis of two of the three telescopes, by in excess of 1 arcminute. This has a small but measureable effect on the assumed spectral responses of the cameras for on-axis targets.; Comment: Accepted by Experimental Astronomy. 26 pages, 18 figures

Study of Four Young TeV Pulsar Wind Nebulae with a Spectral Evolution Model

Tanaka, Shuta J.; Takahara, Fumio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/08/2011 Português
Relevância na Pesquisa
16.53%
We study four young Pulsar Wind Nebulae (PWNe) detected in TeV gamma-rays, G21.5-0.9, G54.1+0.3, Kes 75, and G0.9+0.1, using the spectral evolution model developed and applied to the Crab Nebula in our previous work. We model the evolution of magnetic field and particle distribution function inside a uniformly expanding PWN considering a time-dependent injection from the pulsar and radiative and adiabatic losses. Considering uncertainties in the interstellar radiation field (ISRF) and their distance, we study two cases for each PWN. Because TeV PWNe have a large TeV gamma-rays to X-rays flux ratio, the magnetic energy of the PWNe accounts for only a small fraction of the total energy injected (typically a few x 10^{-3}). The gamma-ray emission is dominated by inverse Compton scattering off the infrared photons of the ISRF. A broken power-law distribution function for the injected particles reproduces the observed spectrum well, except for G0.9+0.1. For G0.9+0.1, we do not need a low energy counterpart because adiabatic losses alone are enough to reproduce the radio observations. High energy power-law indices at injection are similar (2.5 -- 2.6), while low energy power-law indices range from 1.0 to 1.6. The lower limit of the particle injection rate indicates that the pair multiplicity is larger than 10^4. The corresponding upper limit of the bulk Lorentz factor of the pulsar winds is close to the break energy of the broken power-law injection...

The False Premises and Promises of Bitcoin

Hanley, Brian P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.53%
Designed to compete with fiat currencies, bitcoin proposes it is a crypto-currency alternative. Bitcoin makes a number of false claims, including: bitcoin can be a reserve currency for banking; hoarding equals saving, and that we should believe bitcoin can expand by deflation to become a global transactional currency supply. Bitcoin's developers combine technical implementation proficiency with ignorance of currency and banking fundamentals. This has resulted in a failed attempt to change finance. A set of recommendations to change finance are provided in the Afterword: Investment/venture banking for the masses; Venture banking to bring back what investment banks once were; Open-outcry exchange for all CDS contracts; Attempting to develop CDS type contracts on investments in startup and existing enterprises; and Improving the connection between startup tech/ideas, business organization and investment.; Comment: 28 pages, 6 figures. JEL: E21, E22, E42, E51, G21, G29, G28 Section 2.6 has been broken out into a separate paper, and that unwieldy section is replaced by a short bit referencing that new paper titled, "A zero-sum monetary system, interest rates, and implications."

OH (1720 MHz) Masers and Mixed-Morphology Supernova Remnants

Yusef-Zadeh, F.; Wardle, M.; Rho, J.; Sakano, M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/11/2002 Português
Relevância na Pesquisa
16.53%
Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a supernova remnant running into a molecular cloud. An important ingredient of this model is that X-ray emission from the remnant enhances the production of OH molecule. The role of X-ray emission from maser emitting (ME) SNRs is investigated by comparing the X-ray induced ionization rate with theory. One aspect of this model is verified: there is a strong association between maser emitting and mixed-morphology (MM) or thermal composite SNRs --center-filled thermal X-ray emission surrounded by shell-like radio morphology. We also present ROSAT and ASCA observations of two maser emitting SNRs: G21.8--0.6 (Kes 69) and G357.7--0.1 (Tornado).; Comment: 13 pages, 2 tables, 1 figure, ApJ (in press)

Radio and X-ray observations of Five TeV SNRs

Tian, Wenwu; Leahy, Denis
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/10/2010 Português
Relevância na Pesquisa
16.53%
We briefly summarize recent results of five TeV SNRs from radio and X-ray observations. We focus on remeasuring kinematic distances of 5 TeV SNRs, i.e. HESS J1732-347/SNR G353.6-0.7 (3.2 kpc), HESS J1834-087/G23.3-0.3 (also W41, 4.0 kpc), HESS J1833-105/G21.5-0.9 (4.8 kpc), HESS J1846-029/G29.7-0.3 (Kes 75, 6.3 kpc) and TeV SNR G54.1-0.3 (6.5 kpc), and studying non-thermal X-ray emissions from two old SNRs (G353.6-0.7 and W41). These not only allow constraining the TeV SNR basic physical properties, but also help reveal acceleration mechanisms of TeV Gamma-rays in the SNRs which are either related with the SNRs or the pulsar wind nebulae.; Comment: 4 pages, 2 figures. To appear in "The Dynamic ISM: A celebration of the Canadian Galactic Plane Survey," ASP Conference Series, 2011 (Feb.)

Scope for Credit Risk Diversification

Hanson, Samuel; Pesaran, M. Hashem; Schuermann, Til
Fonte: Universidade de Cambridge Publicador: Universidade de Cambridge
Formato: 725876 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
16.53%
This paper considers a simple model of credit risk and derives the limit distribution of losses under different assumptions regarding the structure of systematic risk and the nature of exposure or firm heterogeneity. We derive fat-tailed correlated loss distributions arising from Gaussian risk factors and explore the potential for risk diversification. Where possible the results are generalised to non-Gaussian distributions. The theoretical results indicate that if the firm parameters are heterogeneous but come from a common distribution, for sufficiently large portfolios there is no scope for further risk reduction through active portfolio management. However, if the firm parameters come from different distributions, then further risk reduction is possible by changing the portfolio weights. In either case, neglecting parameter heterogeneity can lead to underestimation of expected losses. But, once expected losses are controlled for, neglecting parameter heterogeneity can lead to overestimation of risk, whether measured by unexpected loss or value-at-risk.

O sistema brasileiro de instituições financeiras subnacionais para o desenvolvimento: um panorama

de Araujo, Victor Leonardo; Pires, Murilo José de Souza; da Silva, Márcio Francisco; de Castro, Diego Afonso
Fonte: Nova Economia; Nova Economia Publicador: Nova Economia; Nova Economia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/05/2014 Português
Relevância na Pesquisa
16.53%
O objetivo deste trabalho é oferecer um panorama sobre a experiência brasileira recente com o sistema composto das instituições financeiras públicas que chamaremos de “subnacionais”, voltadas para o financiamento do desenvolvimento: um banco regional de desenvolvimento, três bancos estaduais de desenvolvimento e 13 agências estaduais de fomento. Em geral, esse sistema é débil, possui fontes de funding pouco diversificadas e depende do BNDES e dos governos estaduais. As operações de crédito oriundas das instituições financeiras subnacionais para o desenvolvimento (IFDs-SN) são qualitativamente distintas das dos bancos públicos federais brasileiros. Salvo o setor comercial, em todos os demais as operações de crédito cresceram a taxas inferiores à média do Sistema Financeiro Nacional (SFN) ou mesmo dos bancos públicos, à exceção do ano de 2009, revelando que as IFDs-SN contribuíram para a ação anticíclica implementada pelos bancos públicos brasileiros após a crise financeira internacional.

Estrutura do setor bancário e o ciclo recente de expansão do crédito: O papel dos bancos públicos federais

de Paula, Luiz Fernando; Oreiro, José Luis; Basilio, Flavio A. C.
Fonte: Nova Economia; Nova Economia Publicador: Nova Economia; Nova Economia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/05/2014 Português
Relevância na Pesquisa
16.53%
Este artigo tem por objetivo analisar a evolução recente da estrutura do setor bancário brasileiro e o ciclo recente do crédito no Brasil, focalizando em especial no desempenho e no papel dos bancos públicos, emparticular os grandes bancos federais – BNDES, Banco do Brasil e CEF. Em particular, destaca-se o papel contracíclico dos bancos públicos no mercado de crédito, além de sua importância no desenvolvimento de algumas linhas de financiamento de mais longo prazo, como financiamento do investimento, crédito agrícola e crédito habitacional. A ênfase do estudo se dá no período pós-real e no boom recente do crédito, ou seja, o período 2003-2009.

A análise da eficiência no setor bancário: Modelo de fronteira estocástica com dados em painel para a banca portuguesa

Martins, Francisco Vitorino da Silva; Ribeiro, Maria Clara Dias Pinto
Fonte: Nova Economia; Nova Economia Publicador: Nova Economia; Nova Economia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/05/2014 Português
Relevância na Pesquisa
16.53%
O objetivo deste estudo é a análise da eficiência produtiva sobre os custos bancários, tendo por base a banca portuguesa. Nesta investigação adotou-se a abordagem de intermediação na conceItualização da empresa bancária. Incluem-se na análise da eficiência os custos financeiros além dos operacionais. A especificação custo adotada é a forma funcional Fourier devido ao caráter multiproduto da empresa bancária. A amostra corresponde à quase totalidade dos bancos portugueses com dados não consolidados em painel. O estudo da ineficiência é elaborado recorrendo ao modelo estocástico da curva fronteira. A taxa de ineficiência média estimada é de cerca de 4%. Em síntese, o processo de concentração, ainda inacabado, do sector bancário português, parece justificar-se pela possibilidade de diminuição da ineficiência-X.

Comportamento dos fatores determinantes da oferta de crédito nos municípios catarinenses no período de 1999 a 2004 DOI:10.5007/2175-8085.2010v13n2p106

Kroth, Darlan Christiano; Curso de Ciências Econômicas da Universidade Comunitária da Região de Chapecó; Sofiatti, Daiane; Universidade Comunitária da Região de Chapecó
Fonte: UFSC Publicador: UFSC
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 16/11/2011 Português
Relevância na Pesquisa
16.53%
O objetivo deste artigo é verificar como algumas variáveis sugeridas pela literatura de microeconomia bancária teriam contribuído para a ampliação da oferta de crédito nos municípios catarinenses no período de 1999 a 2004. Para tanto foi realizado estudo econométrico nos métodos cross-section e dados de painel, abrangendo 220 municípios. Este estudo é pertinente dado que, de acordo com vários autores, o sistema financeiro, via oferta de crédito, age diretamente sobre o crescimento econômico de um país. Todavia, a propensão dos bancos a ofertarem crédito é subjetiva, e depende do comportamento de diversos fatores, seja eles de natureza do demandante do crédito, seja de natureza de conjuntura macroeconômica. As principais conclusões são que a produtividade, o nível de desenvolvimento financeiro e o estoque de capital humano são as variáveis que melhor explicam a oferta de crédito nos municípios catarinenses no período.