INTEGRAL observation of the high-mass X-ray transient V 0332+53 during the 2005 outburst decline

The decline of the high mass X-ray transient V 0332+53 during the Dec. 2004 to Feb. 2005 outburst is analysed from the data recorded by INTEGRAL. The flux is shown to decrease exponentially until 2005 Feb. 10, with a decay time scale of ∼30 days above 20 keV and ∼20 days at lower energies, and to decrease linearly thereafter. The energy spectrum is well modelled throughout the decay by a power law with a folding energy of ∼7.5 keV, and with two cyclotron absorption features. The folding energy does not vary significantly over the decay, but the spectrum becomes harder with time. Most importantly, we show that the parameters describing the fundamental cyclotron line around 27 keV do vary with time: its energy and depth increase (by about 17% for the energy in ∼6 weeks), while its width decreases. These changes of the cyclotron line parameters are interpreted as resulting from a change in the extent of the cyclotron scattering region. Two quasi-periodic oscillations are also observed at various times during the observations, one at 0.05 Hz and another one near the pulsation frequency around 0.23 Hz

Gene frequencies of BoLA-DRB3 alleles estimated through sequence-based typing (PCR-SBT) in a Holstein population of La Pampa province

El objetivo del presente estudio consistió en estimar las frecuencias alélicas del exón 2 del gen de Clase II del Sistema Principal de Histocompatibilidad BoLA-DRB3 en una población de ganado Holstein de la provincia de La Pampa. Los polimorfismos presentes en el exón 2 del gen BoLA-DRB3 se identificaron mediante la técnica de secuenciación directa (PCR-SBT). Los resultados obtenidos permitieron detectar un total de 21 alelos con un rango de frecuencia de 0,014 a 0,222. Esto resultó en una heterocigosidad esperada de 0,91. Estos resultados se compararon con los reportados para ganado Holstein de Japón, evidenciando que con la excepción del alelo BoLA-DRB3*1201, ambas poblaciones presentaron los mismo alelos mayoritarios (BoLA-DRB3*1101, *1501 y *0101). Este resultado sería consecuencia del alto nivel de homogeneidad exhibido por esta raza, debido al uso de la misma genética a nivel global.The objective of this study was to estimate allele frequencies of the BoLA-DRB3 exon 2 in a Holstein population from La Pampa province. The exon 2 polymorphisms were genotyped by sequence-based typing method (PCR-SBT). In the studied herd, a total of 21 variants were detected, ranging from 0.014 to 0.222. This resulted in an expected heterozygocity of 0.91. Obtained data were compared with those reported for Japanese Holstein population, showing that with the exception of BoLA-DRB3*1201 allele, both populations shared the same major variants (BoLA-DRB3*1101, *1501 and *0101). This result could be consequence of the high level of homogeneity present in Holstein breed, due to the use of same genetic on the whole world.Fil: Baltian, Laura Rosana. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Ripoli, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Takeshima, S. N.. Riken. Viral Infectious Diseases Unit; JapónFil: Aida, Y.. Riken. Viral Infectious Diseases Unit; JapónFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin

ASCA Observations of the Jet Source XTE J1748-288

XTE J1748-288 is a new X-ray transient with a one-sided radio jet. It was observed with ASCA on 1998/09/06 and 1998/09/26, 100 days after the onset of the radio-X-ray outburst. The spectra were fitted with an attenuated power-law model, and the 2-6-keV flux was 4.6 * 10^{-11} erg s^{-1} cm^{-2} and 2.2 * 10^{-12} on 09/06 and 09/26, respectively. The light curve showed that the steady exponential decay with an e-folding time of 14 days lasted over 100 days and 4 orders of magnitude from the peak of the outburst. The celestial region including the source had been observed with ASCA on 1993/10/01 and 1994/09/22, years before the discovery. In those period, the flux was < 10^{-13} erg s^{-1} cm^{-2}, below ASCA's detection limit. The jet blob colliding to the environmental matter was supposedly not the X-ray source, although the emission mechanism has not been determined. A possible detection of a K line from highly ionized iron is discussed.Comment: 11 pages, 4 figures, submitted to ApJL. Fig2 is replaced with correct on

Estimation of bovine leukemia virus (BLV) proviral load harbored by lymphocyte subpopulations in BLV-infected cattle at the subclinical stage of enzootic bovine leucosis using BLV-CoCoMo-qPCR

Background: Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis (EBL), which is the most common neoplastic disease of cattle. BLV infection may remain clinically silent at the aleukemic (AL) stage, cause persistent lymphocytosis (PL), or, more rarely, B cell lymphoma. BLV has been identified in B cells, CD2+ T cells, CD3+ T cells, CD4+ T cells, CD8+ T cells, γ/δ T cells, monocytes, and granulocytes in infected cattle that do not have tumors, although the most consistently infected cell is the CD5+ B cell. The mechanism by which BLV causes uncontrolled CD5+ B cell proliferation is unknown. Recently, we developed a new quantitative real-time polymerase chain reaction (PCR) method, BLV-CoCoMo-qPCR, which enabled us to demonstrate that the proviral load correlates not only with BLV infection, as assessed by syncytium formation, but also with BLV disease progression. The present study reports the distribution of BLV provirus in peripheral blood mononuclear cell subpopulations isolated from BLV-infected cows at the subclinical stage of EBL as examined by cell sorting and BLV-CoCoMo-qPCR.Results: Phenotypic characterization of five BLV-infected but clinically normal cattle with a proviral load of > 100 copies per 1 × 105 cells identified a high percentage of CD5+ IgM+ cells (but not CD5- IgM+ B cells, CD4+ T cells, or CD8+T cells). These lymphocyte subpopulations were purified from three out of five cattle by cell sorting or using magnetic beads, and the BLV proviral load was estimated using BLV-CoCoMo-qPCR. The CD5+ IgM+ B cell population in all animals harbored a higher BLV proviral load than the other cell populations. The copy number of proviruses infecting CD5- IgM+ B cells, CD4+ cells, and CD8+ T cells (per 1 ml of blood) was 1/34 to 1/4, 1/22 to 1/3, and 1/31 to 1/3, respectively, compared with that in CD5+ IgM+ B cells. Moreover, the BLV provirus remained integrated into the genomic DNA of CD5+ IgM+ B cells, CD5- IgM+ B cells, CD4+ T cells, and CD8+ T cells, even in BLV-infected cattle with a proviral load of <100 copies per 105 cells.Conclusions: The results of the recent study showed that, although CD5+ IgM+ B cells were the main cell type targeted in BLV-infected but clinically normal cattle, CD5- IgM+ B cells, CD4+ cells, and CD8+ T cells were infected to a greater extent than previously thought.Facultad de Ciencias Veterinaria

Observation of X-ray lines from a Gamma-Ray Burst (GRB991216): Evidence of Moving Ejecta from the Progenitor

We report on the discovery of two emission features observed in the X-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 Dec. 1999 by the Chandra X-Ray Observatory. These features are identified with the Ly$_{\alpha}$ line and the narrow recombination continuum by hydrogenic ions of iron at a redshift $z=1.00\pm0.02$, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, \approx 0.01 \Ms of iron at a velocity $\approx 0.1 c$, probably by a supernova explosion.Comment: 11 pages,2 fig.s, link to the published paper in Science, 290, 955 (2000) through http://www.ias.rm.cnr.it/grb/gb991216.htm

Auger Recombination in Semiconductor Quantum Wells

The principal mechanisms of Auger recombination of nonequilibrium carriers in semiconductor heterostructures with quantum wells are investigated. It is shown for the first time that there exist three fundamentally different Auger recombination mechanisms of (i) thresholdless, (ii) quasi-threshold, and (iii) threshold types. The rate of the thresholdless Auger process depends on temperature only slightly. The rate of the quasi-threshold Auger process depends on temperature exponentially. However, its threshold energy essentially varies with quantum well width and is close to zero for narrow quantum wells. It is shown that the thresholdless and the quasi-threshold Auger processes dominate in narrow quantum wells, while the threshold and the quasi-threshold processes prevail in wide quantum wells. The limiting case of a three-dimensional (3D)Auger process is reached for infinitely wide quantum wells. The critical quantum well width is found at which the quasi-threshold and threshold Auger processes merge into a single 3D Auger process. Also studied is phonon-assisted Auger recombination in quantum wells. It is shown that for narrow quantum wells the act of phonon emission becomes resonant, which in turn increases substantially the coefficient of phonon-assisted Auger recombination. Conditions are found under which the direct Auger process dominates over the phonon-assisted Auger recombination at various temperatures and quantum well widths.Comment: 38 pages, 7 figure

BoLA-DRB3 genetic diversity in Highland Creole cattle from Bolivia

The genetic diversity of the BoLA‐DRB3 gene has been reported in different cattle breeds owing to its central role in the immune response. However, it is still unknown in hundreds of cattle breeds, especially native populations. Here, we studied BoLA‐DRB3 genetic diversity in Highland Creole cattle (CrAl) from Western Bolivia, raised at altitudes between 3800 and 4200 m. DNAs from 48 CrAl cattle were genotyped for BoLA‐DRB3 exon 2 alleles using polymerase chain reaction‐sequence‐based typing (PCR‐SBT). The results were compared with 1341 previously reported data from Tropical Creole cattle and other breeds raised in the region. Twenty‐three BoLA‐DRB3 alleles were identified in CrAl, including the BoLA‐DRB3*029:02 variant previously detected in other Creole cattle. Observed and expected heterozygosity were 0.87 and 0.93, respectively. Nucleotide diversity and the number of pairwise difference values were 0.078 and 19.46, respectively. The average number of nonsynonymous and synonymous substitutions were 0.037 and 0.097 for the entire BoLA‐DRB3 exon 2, and 0.129 and 0.388 for the antigen‐binding site, respectively. Venn analysis and the review of the IPD‐MHC database and the literature showed that 2 of 64 alleles were only detected in CrAl, including BoLA‐DRB3*029:01 previously reported in African cattle and *048:01 detected in Philippine cattle. Two additional alleles, BoLA‐DRB3*007:02 and *029:02, were only present in CrAl and Lowland Creole cattle. Principal Component Analysis (PCA) showed that Bolivian Creole cattle breeds were closely located but they were distant from the Colombian Hartón del Valle Creole. FST analysis showed a low degree of genetic differentiation between Highland and Lowland Bolivian Creole cattle (FST = 0.015). The present results contribute to increasing our knowledge of BoLA‐DRB3 genetic diversity in cattle breeds.Fil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Takeshima, Shin Nosuke. Jumonji University; JapónFil: Moe, Kyaw Kyaw. University of Veterinary Science; BirmaniaFil: Pereira Rico, Juan A.. Universidad Autonoma Gabriel Rene Moreno; BoliviaFil: Polat, Meripet. Viral Infectious Diseases Unit; JapónFil: Loza Vega, Ariel. Universidad Autonoma Gabriel Rene Moreno; BoliviaFil: Arce Cabrera, Orlando N.. Universidad Técnica de Oruro; BoliviaFil: Aida, Yoko. Viral Infectious Diseases Unit; Japó

Gene frequencies of BoLA-DRB3 alleles estimated through sequence-based typing(PCR-SBT) in a Holstein population of La Pampa province

El objetivo del presente estudio consistió en estimar las frecuencias alélicas del exón 2 del gen de Clase II del Sistema Principal de Histocompatibilidad BoLA-DRB3 en una población de ganado Holstein de la provincia de La Pampa. Los polimorfismos presentes en el exón 2 del gen BoLA-DRB3 se identificaron mediante la técnica de secuenciación directa (PCR-SBT). Los resultados obtenidos permitieron detectar un total de 21 alelos con un rango de frecuencia de 0,014 a 0,222. Esto resultó en una heterocigosidad esperada de 0,91. Estos resultados se compararon con los reportados para ganado Holstein de Japón, evidenciando que con la excepción del alelo BoLA-DRB3*1201, ambas poblaciones presentaron los mismo alelos mayoritarios (BoLA-DRB3*1101, *1501 y *0101). Este resultado sería consecuencia del alto nivel de homogeneidad exhibido por esta raza, debido al uso de la misma genética a nivel global.The objective of this study was to estimate allele frequencies of the BoLA-DRB3 exon 2 in a Holstein population from La Pampa province. The exon 2 polymorphisms were genotyped by sequence-based typing method (PCR-SBT). In the studied herd, a total of 21 variants were detected, ranging from 0.014 to 0.222. This resulted in an expected heterozygocity of 0.91. Obtained data were compared with those reported for Japanese Holstein population, showing that with the exception of BoLA-DRB3*1201 allele, both populations shared the same major variants (BoLA-DRB3*1101, *1501 and *0101). This result could be consequence of the high level of homogeneity present in Holstein breed, due to the use of same genetic on the whole world.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari

Gene frequencies of BoLA-DRB3 alleles estimated through sequence-based typing(PCR-SBT) in a Holstein population of La Pampa province

El objetivo del presente estudio consistió en estimar las frecuencias alélicas del exón 2 del gen de Clase II del Sistema Principal de Histocompatibilidad BoLA-DRB3 en una población de ganado Holstein de la provincia de La Pampa. Los polimorfismos presentes en el exón 2 del gen BoLA-DRB3 se identificaron mediante la técnica de secuenciación directa (PCR-SBT). Los resultados obtenidos permitieron detectar un total de 21 alelos con un rango de frecuencia de 0,014 a 0,222. Esto resultó en una heterocigosidad esperada de 0,91. Estos resultados se compararon con los reportados para ganado Holstein de Japón, evidenciando que con la excepción del alelo BoLA-DRB3*1201, ambas poblaciones presentaron los mismo alelos mayoritarios (BoLA-DRB3*1101, *1501 y *0101). Este resultado sería consecuencia del alto nivel de homogeneidad exhibido por esta raza, debido al uso de la misma genética a nivel global.The objective of this study was to estimate allele frequencies of the BoLA-DRB3 exon 2 in a Holstein population from La Pampa province. The exon 2 polymorphisms were genotyped by sequence-based typing method (PCR-SBT). In the studied herd, a total of 21 variants were detected, ranging from 0.014 to 0.222. This resulted in an expected heterozygocity of 0.91. Obtained data were compared with those reported for Japanese Holstein population, showing that with the exception of BoLA-DRB3*1201 allele, both populations shared the same major variants (BoLA-DRB3*1101, *1501 and *0101). This result could be consequence of the high level of homogeneity present in Holstein breed, due to the use of same genetic on the whole world.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari