Storage; analysis and communication of information from diverse wheat field trials

Tese de doutoramento em Gestão de Empresas apresentada à Faculdade de Economia da Universidade de CoimbraNas últimas décadas, grandes transformações ocorreram no ambiente competitivo internacional, provocando mudanças significativas no mercado externo e acelerando o processo de internacionalização das empresas, para que possam se manter competitivas. Portanto, esta tese investiga como se articulam os vários antecedentes da internacionalização de empresas brasileiras e avalia a intensidade das relações existentes entre a orientação para o mercado externo, a orientação empreendedora internacional, os recursos e a inovação e o seu impacto na performance exportadora. Este estudo visa a aprofundar o conhecimento sobre a capacidade destes construtos influenciarem o resultado das empresas brasileiras que operam no mercado internacional e avaliarem as relações agregadas entre eles. Para isso, alguns passos foram fundamentais no desenvolvimento da pesquisa: a proposição de um modelo teórico hipotetizando as relações entre os temas; a validação de escalas confiáveis; o teste empírico das hipóteses. As empresas brasileiras exportadoras foram definidas como população-alvo, conforme cadastro oficial da Secretaria de Comércio Exterior (Secex) do Ministério do Desenvolvimento, Indústria e Comércio Exterior (MDIC). A amostra foi composta de 406 empresas pesquisadas. Na análise dos dados aplicou-se a técnica multivariada dos dados, por meio da modelagem de equações estruturais (MEE) e a técnica de redes neurais artificiais (RNA). Testou-se o modelo hipotético através da análise fatorial confirmatória (AFC) e os resultados confirmaram 8 entre as 10 hipóteses estabelecidas a partir do modelo adotado nesta tese. Os resultados apontaram um efeito positivo e integrado entre os construtos antecedentes e a performance exportadora, conforme proposto no modelo estrutural. Os impactos mais fortes do modelo estabeleceram-se nas relações entre a orientação para o mercado externo e os recursos, e na relação entre a orientação empreendedora internacional e a orientação para o mercado externo. Os resultados obtidos através da técnica de redes neurais apresentaram 10 construtos de 1ª ordem com pesos positivos na relação com a performance exportadora e somente 4 com pesos negativos (inibidores). No comparativo entre as duas técnicas de análise, os resultados foram semelhantes, o que pode mostrar que a linearidade das relações é a realidade dominante. No cômputo geral os resultados confirmaram que os construtos de orientação para o mercado externo, a orientação empreendedora internacional, os recursos e a inovação influenciam positivamente na performance exportadora das empresas

RXTE Observations of the SGR 1806-20 Steady Emission

We discuss observations of the quiescent emission from the soft gamma repeater SGR 1806-20 by the Rossi X-ray Timing Explorer. We find that the 2-20 keV RXTE data is consistent with a constant spectral shape during both active bursting periods and periods of relative quiescence, and is best described by a nonthermal (power law) spectral shape. Using archival ASCA data we find that the quiescent spectrum of SGR 1806-20 is well fit over the energy range 1-30 keV by a power law of photon index 2.31 +/- 0.04, with thermal bremsstrahlung and Raymond-Smith models producing much worse fits to the data.Comment: Total 4 pages, 1 figure, and 2 style files. To appear in the proceedings of the conference "Neutron Stars and Pulars - Thirty years after the Discovery", held Novermber 17-20, 1997 in Toky

Discovery of a New Soft Gamma Repeater, SGR 1627-41

We report the discovery of a new soft gamma repeater (SGR), SGR 1627-41, and present BATSE observations of the burst emission and BeppoSAX NFI observations of the probable persistent X-ray counterpart to this SGR. All but one burst spectrum are well fit by an optically thin thermal bremsstrahlung (OTTB) model with kT values between 25 and 35 keV. The spectrum of the X-ray counterpart, SAX J1635.8-4736, is similar to that of other persistent SGR X-ray counterparts. We find weak evidence for a periodic signal at 6.41 s in the light curve for this source. Like other SGRs, this source appears to be associated with a young supernova remnant G337.0-0.1. Based upon the peak luminosities of bursts observed from this SGR, we find a lower limit on the dipole magnetic field of the neutron star B_dipole > 5 * 10^14 Gauss.Comment: 5 pages, 4 figures, submitted to ApJ Letter

A coordinated optical and X-ray spectroscopic campaign on HD179949: searching for planet-induced chromospheric and coronal activity

HD179949 is an F8V star, orbited by a close-in giant planet with a period of ~3 days. Previous studies suggested that the planet enhances the magnetic activity of the parent star, producing a chromospheric hot spot which rotates in phase with the planet orbit. However, this phenomenon is intermittent since it was observed in several but not all seasons. A long-term monitoring of the magnetic activity of HD179949 is required to study the amplitude and time scales of star-planet interactions. In 2009 we performed a simultaneous optical and X-ray spectroscopic campaign to monitor the magnetic activity of HD179949 during ~5 orbital periods and ~2 stellar rotations. We analyzed the CaII H&K lines as a proxy for chromospheric activity, and we studied the X-ray emission in search of flux modulations and to determine basic properties of the coronal plasma. A detailed analysis of the flux in the cores of the CaII H&K lines and a similar study of the X-ray photometry shows evidence of source variability, including one flare. The analysis of the the time series of chromospheric data indicates a modulation with a ~11 days period, compatible with the stellar rotation period at high latitudes. Instead, the X-ray light curve suggests a signal with a period of ~4 days, consistent with the presence of two active regions on opposite hemispheres. The observed variability can be explained, most likely, as due to rotational modulation and to intrinsic evolution of chromospheric and coronal activity. There is no clear signature related to the orbital motion of the planet, but the possibility that just a fraction of the chromospheric and coronal variability is modulated with the orbital period of the planet, or the stellar-planet beat period, cannot be excluded. We conclude that any effect due to the presence of the planet is difficult to disentangle

The Cross-Spectra of Cir X-1: Evolution of Time Lags

Earlier work showed that the track in the X-ray hardness-intensity diagram of Cir X-1 corresponds to a Z track in its color-color diagram. In this paper, we study the cross spectrum of Cir X-1 in different regions of the hardness-intensity diagram with $RXTE$/PCA data. Comparing the light curves of Cir X-1 for the energy band 1.8-5.1 keV to those for 5.1-13.1 keV, we find that Cir X-1 exhibits a hard time lag on the horizontal branch, and a soft time lag on both the normal and the flaring branch. This indicates that Cir X-1 is similar to GX 5-1 and Cyg X-2 on the horizontal branch, but is different from them on the normal branch. We briefly discuss the mechanism of the time lags in the context of Comptonization models.Comment: 12 pages, 4 figures, accepted for publication in Ap

RXTE Observations of the Anomalous Pulsar 4U 0142+61

We observed the anomalous X-ray pulsar 4U 0142+61 using the Proportional Counter Array (PCA) aboard the Rossi X-ray Timing Explorer (RXTE) in March 1996. The pulse frequency was measured as f = 0.11510039(3) Hz with an upper limit of df/dt < 4 * 10^(-13) Hz/s upon the short term change in frequency over the 4.6 day span of the observations. A compilation of all historical measurements showed an overall spin-down trend with slope df/dt = (-3.0 +/- 0.1) * 10^(-14) Hz/s. Searches for orbital modulations in pulse arrival times yielded an upper limit of a_x sin i < 0.26 lt-s (99% confidence) for the period range 70 s to 2.5 days. These limits combined with previous optical limits and evolutionary arguments suggest that 4U 0142+61 is probably not a member of a binary system.Comment: 20 pages (LaTeX) including 7 figures. Accepted for publication in the Astrophysical Journa