A Multi-Wavelength Study of the Western Lobe of W50 Powered by the Galactic Microquasar SS 433

W50 remains the only supernova remnant (SNR) confirmed to harbor a microquasar: the powerful enigmatic source SS 433. Our past study of this fascinating SNR revealed two X-ray lobes distorting the radio shell as well as non-thermal X-rays at the site of interaction between the SS 433 eastern jet and the eastern lobe of W50. In this paper we present the results of a 75 ksec CHANDRA ACIS-I observation of the peak of W50-west targeted to 1) determine the nature of the X-ray emission and 2) correlate the X-ray emission with that in the radio and infrared domains. We have confirmed that at the site of interaction between the western jet of SS 433 and dense interstellar gas the X-ray emission is non-thermal in nature. The helical pattern observed in radio is also seen with CHANDRA. No correlation was found between the infrared and X-ray emission.Comment: A refereed publication, submitted Sept. 30, 2004, accepted Jan. 12, 2005, to appear in Advances in Space Research. 7 pages, including 4 figures (3 color) & 1 table (the resolution of most figures has been reduced for astro-ph submission only). A gzipped postscript or pdf version of the paper with high-resolution images can be downloaded from: http://aurora.physics.umanitoba.ca/~moldowan/Astro-Ph

Multiplexed communication over a high-speed quantum channel

In quantum information systems it is of particular interest to consider the best way in which to use the non-classical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are amongst the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analogue bandwidth. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4 GHz comb of vacuum squeezing produced by a sub-threshold OPO, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel

The association between region of birth and sexually transmitted infections among people of black Caribbean ethnicity attending sexual health services in England, 2015.

BACKGROUND/INTRODUCTION: In England, people of Black Caribbean (BC) ethnicity are disproportionately affected by sexually transmitted infections (STIs), but it is unclear whether this varies by their region of birth. AIM(S)/OBJECTIVES: To examine differences in STI diagnoses among UK- and Caribbean-born BC people. METHODS: Data on STI diagnoses in BC people attending specialist sexual health services (SHSs) during 2015 and living in England were obtained from the GUMCAD STI surveillance system, the national surveillance system for STIs in England. Associations between being UK- or Caribbean-born and each of several STI diagnoses were examined, using univariate and multivariable generalised estimated equations logistic regression models adjusted for sexual orientation, place of residence (London vs. non-London), HIV status, area-level deprivation, and STI diagnosis in the last year. All analyses were stratified by age (<25 vs. ≥25 years). RESULTS: In 2015, 63,568 BC people made 108,881 attendances at specialist SHSs; 81.9% of these attendances were made by UK-born BCs. The median age (years) was 26 for UK-born and 35 for Caribbean-born people (p≤0.001). Chlamydia, gonorrhoea and non-specific genital infection (NSGI) were the most commonly diagnosed STIs among UK- (5.8%, 2.1% and 2.8%) and Caribbean-born people (4.5%, 1.7% and 3.5%) respectively. Among BCs aged under 25, no significant differences in STIs were found between UK- and Caribbean-born people. Among BCs aged ≥25, compared to Caribbean-born people, those who were UK-born were more likely to be diagnosed with chlamydia (AOR 1.15 [95%C.I. 1.04-1.27]); gonorrhoea (AOR 1.23 [95%C.I. 1.06-1.45]) and genital herpes (AOR 1.23 [95% C.I. 1.10-1.56]) and less likely to be diagnosed with NSGI (AOR 0.89 [95% C.I. 0.80-0.99]) and Trichomoniasis (AOR 0.84 [95% C.I. 0.71-0.99]). DISCUSSION/CONCLUSION: STI diagnoses in BC people aged ≥25 attending specialist SHSs vary by region of birth. Country of birth may have an influence on social and sexual networks and therefore transmission of STIs

Meeting report:Fungal genomics meets social media: Highlights of the 28th fungal genetics conference at asilomar

International audienc

Brown adipose tissue and regulation of human body weight

Background: Approximately 30% of the global population is affected by obesity. Traditional non-surgical measures for weight loss have limited efficacy and tolerability. Therefore, there is a need for novel, effective therapies. Brown adipose tissue (BAT) has been implicated in physiological energy expenditure, indicating that it could be targeted to achieve weight loss in humans. The use of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography—computed tomography—(PET-CT) imaging has enabled the discovery of functionally active BAT in the supraclavicular, subclavian, and thoracic spine regions of human adults. This review aims to discuss the reasons behind the renewed interest in BAT, assess whether it is metabolically important in humans, and evaluate its feasibility as a therapeutic target for treating obesity. Sources of material: PubMed Central, Europe PMC, Medline. Findings: In vivo studies have shown that BAT activity is regulated by thyroid hormones and the sympathetic nervous system. Furthermore, BAT uniquely contains uncoupling protein 1 (UCP1) that is largely responsible for non-shivering thermogenesis. Cold exposure can increase BAT recruitment through the browning of white adipose tissue (WAT); however, this technique has practical limitations that may preclude its use. Currently available medicines for humans, such as the β3-adrenergic receptor agonist mirabegron or the farnesoid X receptor agonist obeticholic acid, have generated excitement, although adverse effects are a concern. Capsinoids represent a tolerable alternative, which require further investigation. Conclusions: The use of currently available BAT-activating agents alone is unlikely to achieve significant weight loss in humans. A combination of BAT activation with physical exercise and modern, successful dietary strategies represents a more realistic option

Can optical squeezing be generated via polarization self-rotation in a thermal vapour cell?

The traversal of an elliptically polarized optical field through a thermal vapour cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. In this paper, we show results of the characterization of PSR in isotopically enhanced Rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapour overwhelms the observation of squeezing. We present a theory that contains atomic noise terms and show that a null result in squeezing is consistent with this theory.Comment: 10 pages, 11 figures, submitted to PRA. Please email author for a PDF file if the article does not appear properl

X-Ray Observations of the supernova remnant G21.5-0.9

We present the analysis of archival X-ray observations of the supernova remnant (SNR) G21.5-0.9. Based on its morphology and spectral properties, G21.5-0.9 has been classified as a Crab-like SNR. In their early analysis of the CHANDRA calibration data, Slane et al. (2000) discovered a low-surface-brightness, extended emission. They interpreted this component as the blast wave formed in the supernova (SN) explosion. In this paper, we present the CHANDRA analysis using a total exposure of ~150 ksec. We also include ROSAT and ASCA observations. Our analysis indicates that the extended emission is non-thermal -- a result in agreement with XMM observations. The entire remnant of radius ~ 2'.5 is best fitted with a power law model with a photon index steepening away from the center. The total unabsorbed flux in the 0.5-10 keV is 1.1E-10 erg/cm2/s with an 85% contribution from the 40" radius inner core. Timing analysis of the High-Resolution Camera (HRC) data failed to detect any pulsations. We put a 16% upper limit on the pulsed fraction. We derive the physical parameters of the putative pulsar and compare them with those of other plerions (such as the Crab and 3C 58). G21.5-0.9 remains the only plerion whose size in X-rays is bigger than in the radio. Deep radio observations will address this puzzle.Comment: 23 pages including 11 figures and 3 tables; accepted by ApJ June 22, 2001; to appear in Oct 20, 2001 issue of Ap

XMM-Newton X-ray Observation of the High-Magnetic-Field Radio Pulsar PSR J1734--3333

Using observations made with the XMM-Newton Observatory, we report the probable X-ray detection of the high-magnetic-field radio pulsar PSR J1734-3333. This pulsar has an inferred surface dipole magnetic field of B = 5.2e13 G, just below that of one anomalous X-ray pulsar (AXP). We find that the pulsar has an absorbed 0.5-2.0 keV flux of (5-15)e-15 erg/s/cm^2 and that its X-ray luminosity L_X is well below its spin down luminosity E_dot, with L_X < 0.1E_dot. No pulsations were detected in these data although our derived upper limit is unconstraining. Like most of the other high-B pulsars, PSR J1734-3333 is X-ray faint with no sign of magnetar activity. We collect and tabulate the properties of this and all other known high-B radio pulsars with measured X-ray luminosities or luminosity upper limits and plot L_X versus B for them all.Comment: 14 pages, 2 tables, 3 figures, published in the Astrophysical Journal. Includes updated Figure