618 research outputs found

    Neutral absorber dips in the periodic burster LMXB XB 1323-619 from Suzaku

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    We present results of an observation with Suzaku of the dipping, periodic bursting low mass X-ray binary XB 1323-619. Using the energy band 0.8 - 70 keV, we show that the source spectrum is well-described as the emission of an extended accretion disk corona, plus a small contribution of blackbody emission from the neutron star. The dip spectrum is well-fitted by the progressive covering model in which the extended ADC is progressively overlapped by the absorbing bulge of low ionization state in the outer accretion disk and that dipping is basically due to photoelectric absorption in the bulge. An energy-independent decrease of flux at high energies (20 - 70 keV) is shown to be consistent with the level of Thomson scattering expected in the bulge. An absorption feature at 6.67 keV (Fe XXV) is detected in the non-dip spectrum and other possible weak features. In dipping, absorption lines of medium and highly ionized states are seen suggestive of absorption in the ADC but there is no evidence that the lines are stronger than in non-dip. We show that the luminosity of the source has changed substantially since the Exosat observation of 1985, increasing in luminosity between 1985 and 2003, then in 2003 - 2007 falling to the initial low value. X-ray bursting has again become periodic, which it ceased to do in its highest luminosity state, and we find that the X-ray bursts exhibit both the fast decay and later slow decay characteristic of the rp burning process. We present arguments against the recent proposal that the decrease of continuum flux in the dipping LMXB in general can be explained as absorption in an ionized absorber rather than in the bulge in the outer disk generally accepted to be the site of absorption.Comment: 12 pages, 6 figures, Astronomy and Astrophysics in pres

    Highlights from the 2018 European Respiratory Society International Congress: sleep and clinical physiology.

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    The 2018 European Respiratory Society (ERS) International Congress held in Paris, France, served as a platform to discover the latest research on respiratory diseases, the improvement in their treatments and patient care. Specifically, the scientific sessions organised by ERS Assembly 4 provided novel insights into sleep disordered breathing and fresh knowledge in respiratory physiology, stressing its importance to understanding and treating respiratory diseases. This article, divided by session, will summarise the most relevant studies presented at the ERS International Congress. Each session has been written by early career members specialised in the different fields of this interdisciplinary assembly

    TeV-scale seesaw from a multi-Higgs model

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    We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no large flavor changing neutral currents, are satisfied since the extra doublet only has a Yukawa interaction with lepton doublets and right-handed neutrinos, and their masses are heavy of order a TeV-scale. Since active light neutrinos are Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure

    New risks and challenges within the context of OSCE

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    A Organização para a Segurança e Cooperação na Europa (OSCE) é um instrumento fundamental para a cooperação na região Euro- -Atlântica no combate às novas ameaças que surgiram com os atentados de 11 de Setembro. Uma das principais tarefas da OSCE é a de funcionar como um instrumento de alerta precoce no caso de novos desafios e ameaças à segurança internacional. A organização pode ser um fórum onde se estabelecem novas normas e princípios de segurança e processos de cooperação entre os Estados. A luta contra o terrorismo tornou-se uma das prioridades da OSCE, e devido à sua experiência nesse domí- nio pode vir a ter um papel preponderante no âmbito das instituições Euro-Atlânticas

    The influence of sleep deprivation and obesity on DNA damage in female Zucker rats

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    OBJECTIVE: The aim of this study was to evaluate overall genetic damage induced by total sleep deprivation in obese, female Zucker rats of differing ages. METHOD: Lean and obese Zucker rats at 3, 6, and 15 months old were randomly distributed into two groups for each age group: home-cage control and sleep-deprived (N = 5/group). The sleep-deprived groups were deprived sleep by gentle handling for 6 hours, whereas the home-cage control group was allowed to remain undisturbed in their home-cage. At the end of the sleep deprivation period, or after an equivalent amount of time for the home-cage control groups, the rats were brought to an adjacent room and decapitated. The blood, brain, and liver tissue were collected and stored individually to evaluate DNA damage. RESULTS: Significant genetic damage was observed only in 15-month-old rats. Genetic damage was present in the liver cells from sleep-deprived obese rats compared with lean rats in the same condition. Sleep deprivation was associated with genetic damage in brain cells regardless of obesity status. DNA damage was observed in the peripheral blood cells regardless of sleep condition or obesity status. CONCLUSION: Taken together, these results suggest that obesity was associated with genetic damage in liver cells, whereas sleep deprivation was associated with DNA damage in brain cells. These results also indicate that there is no synergistic effect of these noxious conditions on the overall level of genetic damage. In addition, the level of DNA damage was significantly higher in 15-month-old rats compared to younger rats

    Oblique triangular antiferromagnetic phase in CsCu1x_{1-x}Cox_xCl3_3

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    The spin-1/2 stacked triangular antiferromagnet CsCu1x_{1-x}Cox_xCl3_3 with 0.015<x<0.0320.015<x<0.032 undergoes two phase transitions at zero field. The low-temperature phase is produced by the small amount of Co2+^{2+} doping. In order to investigate the magnetic structures of the two ordered phases, the neutron elastic scattering experiments have been carried out for the sample with x0.03x\approx 0.03. It is found that the intermediate phase is identical to the ordered phase of CsCuCl3_3, and that the low-temperature phase is an oblique triangular antiferromagnetic phase in which the spins form a triangular structure in a plane tilted from the basal plane. The tilting angle which is 42^{\circ} at T=1.6T=1.6 K decreases with increasing temperature, and becomes zero at TN2=7.2T_{\rm N2} =7.2 K. An off-diagonal exchange term is proposed as the origin of the oblique phase.Comment: 6 pages, 7 figure

    Immuno-surgical management of pancreatic cancer with analysis of cancer exosomes

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    Exosomes (EXs), a type of extracellular vesicles secreted from various cells and especially cancer cells, mesenchymal cells, macrophages and other cells in the tumor microenvironment (TME), are involved in biologically malignant behaviors of cancers. Recent studies have revealed that EXs contain microRNAs on their inside and express proteins and glycolipids on their outsides, every component of which plays a role in the transmission of genetic and/or epigenetic information in cell-to-cell communications. It is also known that miRNAs are involved in the signal transduction. Thus, EXs may be useful for monitoring the TME of tumor tissues and the invasion and metastasis, processes that are associated with patient survival. Because several solid tumors secrete immune checkpoint proteins, including programmed cell death-ligand 1, the EX-mediated mechanisms are suggested to be potent targets for monitoring patients. Therefore, a companion therapeutic approach against cancer metastasis to distant organs is proposed when surgical removal of the primary tumor is performed. However, EXs and immune checkpoint mechanisms in pancreatic cancer are not fully understood, we provide an update on the recent advances in this field and evidence that EXs will be useful for maximizing patient benefit in precision medicine

    REM-associated sleep apnoea: prevalence and clinical significance in the HypnoLaus cohort

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    This study determined the prevalence of rapid eye movement (REM) related sleep-disordered breathing (REM-SDB) in the general population and investigated the associations of REM-SDB with hypertension, metabolic syndrome, diabetes and depression.Home polysomnography (PSG) recordings (n=2074) from the population-based HypnoLaus Sleep Cohort (48.3% men, 57±11 years old) were analysed. The apnoea-hypopnoea index was measured during REM and non-REM sleep (as REM-AHI and NREM-AHI, respectively). Regression models were used to explore the associations between REM-SDB and hypertension, diabetes, metabolic syndrome and depression in the entire cohort and in subgroups with NREM-AHI &lt;10 events·h &lt;sup&gt;-1&lt;/sup&gt; and total AHI &lt;10 events·h &lt;sup&gt;-1&lt;/sup&gt; The prevalence of REM-AHI ≥20 events·h &lt;sup&gt;-1&lt;/sup&gt; was 40.8% in the entire cohort. An association between increasing REM-AHI and metabolic syndrome was found in the entire cohort and in both the NREM-AHI and AHI subgroups (p-trend=0.014, &lt;0.0001 and 0.015, respectively). An association was also found between REM-AHI ≥20 events·h &lt;sup&gt;-1&lt;/sup&gt; and diabetes in both the NREM-AHI &lt;10 events·h &lt;sup&gt;-1&lt;/sup&gt; (odds ratio (OR) 3.12 (95% CI 1.35-7.20)) and AHI &lt;10 events·h &lt;sup&gt;-1&lt;/sup&gt; (OR 2.92 (95% CI 1.12-7.63)) subgroups. Systolic and diastolic blood pressure were positively associated with REM-AHI ≥20 events·h &lt;sup&gt;-1&lt;/sup&gt; REM-SDB is highly prevalent in our middle-to-older age sample and is independently associated with metabolic syndrome and diabetes. These findings suggest that an increase in REM-AHI could be clinically relevant
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