Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

Hard X-ray spectra of black hole binaries in the low/hard state are well modeled by thermal Comptonization of soft seed photons by a corona-type region with $kT$\thinspace$\sim 50${\thinspace}keV and optical depth around 1. Previous spectral studies of 1E{\thinspace}1740.7$-$2942, including both the soft and the hard X-ray bands, were always limited by gaps in the spectra or by a combination of observations with imaging and non-imaging instruments. In this study, we have used three rare nearly-simultaneous observations of 1E{\thinspace}1740.7$-$1942 by both XMM-Newton and INTEGRAL satellites to combine spectra from four different imaging instruments with no data gaps, and we successfully applied the Comptonization scenario to explain the broadband X-ray spectra of this source in the low/hard state. For two of the three observations, our analysis also shows that, models including Compton reflection can adequately fit the data, in agreement with previous reports. We show that the observations can also be modeled by a more detailed Comptonization scheme. Furthermore, we find the presence of an iron K-edge absorption feature in one occasion, which confirms what had been previously observed by Suzaku. Our broadband analysis of this limited sample shows a rich spectral variability in 1E{\thinspace}1740.7$-$2942 at the low/hard state, and we address the possible causes of these variations. More simultaneous soft/hard X-ray observations of this system and other black-hole binaries would be very helpful in constraining the Comptonization scenario and shedding more light on the physics of these systems.Comment: 6 pages, two figures, accepted for publication in A&

Influência da adubação fosfatada e calagem sobre a absorção do zinco, em dois solos de Minas.

Two experiments were installed in the greenhouse to study the relationships between phosphate fertilization, liming and zinc fertilization. One experiment used a red latosol soil while the other used a dark brown acid soil. Hybrid corn AG 206 was used to plant both experiments. The data collected consisted of dry matter productions level of zinc in the leaves, stems and tootes of the corn as well as the P/Zn and Ca/Zn rations in the leaves. Phosphate fertilization and liming lowed the level of zinc in the corn leaves to a point equal to or lower than 14 ppm. These leves were below 80% of the maximum yields of the experiments. The application of 4,5 ppm of zinc to the soil was adequate to raise the level of zinc in the leaves above the critical level. It also increase the production was limited by a zinc deficiency. The phosphorus and zinc interaction, which ocurred primarily in the roots of the plant, reduced the translocation of zinc to the leaves. The interaction between liming and zinc ocurred prior to the absorption of zinc by the plant. It aprears that there are ratios between phosphorus and zinc between calcium and zinc in the leaves which are critical to good plant growth. The critical P/Zn ratio is betwee 300 and 470 and the critical Ca/Zn ratio between 455-640

Alternativas tecnológicas para o controle de pragas do fruto da gravioleira.

bitstream/CNPAT-2010/11935/1/Pa-040.pd

Estratégias para o controle de pragas do fruto da gravioleira.

bitstream/CNPAT-2010/11956/1/Ct-048.pd

Levantamento e identificação das principais pragas do sapotizeiro.

Este trabalho objetiva preliminarmente, levantar, identificar e conhecer o grau de severidade de dano, bem como a epoca de ocorrencia das principais pragas e insetos beneficos associados ao sapotizeiro e, a partir dai, tracar estrategias ...bitstream/CNPAT-2010/5384/1/Pa-073.pd

Ocorrência e grau de severidade de dano das principais pragas da aceroleira.

bitstream/CNPAT-2010/12036/1/Pa-039.pd

Pragas associadas à aceroleira.

A incidencia de algumas pragas de maior ou menor interesse economica tem sido observada com frequencia em areas irrigadas, destacando-se os pulgoes como a de maior severidade. Esss insetos atacam geralmente a extremidade tenra dos ramos, causando murchamento e morte, o que forca a emitir brotacoes laterais.bitstream/item/33820/1/Ct-038.pd