Probing Jet Launching in Neutron Star X-Ray Binaries: The Variable and Polarized Jet of SAX J1808.4-3658

Indexación ScopusWe report on an optical photometric and polarimetric campaign on the accreting millisecond X-ray pulsar (AMXP) x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">SAX x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">4-x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">J1808.x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">4-x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">3658 during its 2019 outburst. The emergence of a low-frequency excess x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in the spectral energy distribution x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in the form of a red excess above the disk spectrum (seen most prominently x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in the z, i, and R bands) is observed as the outburst evolves. This is indicative of optically thin synchrotron emission due to a jet, as seen previously x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in this source and x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in other AMXPs during outburst. At the end of the outburst decay, the source enters a reflaring state. The low-frequency excess is still observed during the reflares. Our optical (BVRI) polarimetric campaign shows variable linear polarization (LP) throughout the outburst. We show that this is intrinsic to the source, with low-level but significant detections (0.2%-2%) x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in all bands. The LP spectrum is red during both the main outburst and the reflaring state, favoring a jet origin for this variable polarization over other interpretations, such as Thomson scattering with free electrons from the disk or the propelled matter. During the reflaring state, a few episodes with stronger LP levels (1%-2%) are observed. The low-level, variable LP is suggestive of strongly tangled magnetic fields near the base of the jet. These results clearly demonstrate how polarimetry is a powerful tool for x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">probing the magnetic field structure x display--inline-block" style="background: var(--highlight-yellow); color: inherit;">in X-ray binary jets, as for active galactic nuclei jets. © 2020. The American Astronomical Society. All rights reserved..https://iopscience-iop-org.recursosbiblioteca.unab.cl/article/10.3847/1538-4357/abc68

Fusion hindrance and Pauli blocking in 58Ni+64Ni

The early experiments on fusion of Ni + Ni systems are well-known and indicated for the first time the possible influence of transfer reactions on sub- barrier cross sections. The influence of the positive Q-value transfer channels on sub-barrier fusion cross sections of the system 58Ni + 64Ni was evidenced in an exper- iment by Beckerman et al. Subsequent experiments for the two systems 58Ni + 58Ni and 64Ni + 64Ni showed that fusion hindrance is clearly present in both cases. The lowest measured cross section for 58Ni + 64Ni was relatively large (0.1 mb), so that no hindrance was observed. In the present measurement the excitation function has been extended by two orders of magnitude downward. The present experiment in- dicates that the flat trend of the sub-barrier cross sections for 58Ni + 64Ni continues down to the level of μb and the logarithmic slope of the excitation function increases slowly, showing a tendency to saturate at the lowest energies. No maximum of the astrophysical S-factor is observed, so fusion hindrance is not observed. This trend at far sub-barrier energies suggests that the presence of the transfer channel with Q > 0, effectively counterbalances the effect of Pauli repulsion that is predicted to reduce tunneling probability

Fusion hindrance and Pauli blocking in 58^{58}Ni + 64^{64}Ni

International audienceThe early experiments on fusion of Ni + Ni systems are well-known and indicated for the first time the possible influence of transfer reactions on subbarrier cross sections. The influence of the positive Q-value transfer channels on sub-barrier fusion cross sections of the system 58Ni + 64Ni was evidenced in an experiment by Beckerman et al. Subsequent experiments for the two systems 58Ni + 58Ni and 64Ni + 64Ni showed that fusion hindrance is clearly present in both cases. The lowest measured cross section for 58Ni + 64Ni was relatively large (0.1 mb), so that no hindrance was observed. In the present measurement the excitation function has been extended by two orders of magnitude downward. The present experiment indicates that the flat trend of the sub-barrier cross sections for 58Ni + 64Ni continues down to the level of μb and the logarithmic slope of the excitation function increases slowly, showing a tendency to saturate at the lowest energies. No maximum of the astrophysical S-factor is observed, so fusion hindrance is not observed. This trend at far sub-barrier energies suggests that the presence of the transfer channel with Q > 0, effectively counterbalances the effect of Pauli repulsion that is predicted to reduce tunneling probability

Ancestry-shift refinement mapping of the C6orf97-ESR1 breast cancer susceptibility locus.

Contains fulltext : 88175.pdf (publisher's version ) (Open Access)We used an approach that we term ancestry-shift refinement mapping to investigate an association, originally discovered in a GWAS of a Chinese population, between rs2046210[T] and breast cancer susceptibility. The locus is on 6q25.1 in proximity to the C6orf97 and estrogen receptor alpha (ESR1) genes. We identified a panel of SNPs that are correlated with rs2046210 in Chinese, but not necessarily so in other ancestral populations, and genotyped them in breast cancer case:control samples of Asian, European, and African origin, a total of 10,176 cases and 13,286 controls. We found that rs2046210[T] does not confer substantial risk of breast cancer in Europeans and Africans (OR = 1.04, P = 0.099, and OR = 0.98, P = 0.77, respectively). Rather, in those ancestries, an association signal arises from a group of less common SNPs typified by rs9397435. The rs9397435[G] allele was found to confer risk of breast cancer in European (OR = 1.15, P = 1.2 x 10(-3)), African (OR = 1.35, P = 0.014), and Asian (OR = 1.23, P = 2.9 x 10(-4)) population samples. Combined over all ancestries, the OR was 1.19 (P = 3.9 x 10(-7)), was without significant heterogeneity between ancestries (P(het) = 0.36) and the SNP fully accounted for the association signal in each ancestry. Haplotypes bearing rs9397435[G] are well tagged by rs2046210[T] only in Asians. The rs9397435[G] allele showed associations with both estrogen receptor positive and estrogen receptor negative breast cancer. Using early-draft data from the 1,000 Genomes project, we found that the risk allele of a novel SNP (rs77275268), which is closely correlated with rs9397435, disrupts a partially methylated CpG sequence within a known CTCF binding site. These studies demonstrate that shifting the analysis among ancestral populations can provide valuable resolution in association mapping

PREPARO DO GRADUANDO DE ENFERMAGEM PARA ATUAR NA COMISSÃO DE CONTROLE DE INFECÇÃO HOSPITALAR (CCIH)

The goal this study is to verify how is the preparation of nursing student during undergraduate course in Brasil in order to work as a member of Hospital Infection Control Committee (HICC). The results demonstrated that this teaching is assistematic and not planned. The authors propose a teaching recomendation on nurse's practice job in the HICC.Este trabalho teve por finalidade realizar estudo sobre como as escolas de enfermagem do país estão preparando o graduando de enfermagem para atuar na comissão de controle de infecção hospitalar (CCIH); observamos que este ensino não vem sendo desenvolvido de maneira sistemática e planejada. A partir dos resultados obtidos, apresentamos uma proposta de ensino formal sobre a atuação da enfermeira na CCIH