Explore the vast range of titles available.

The diffuse far-ultraviolet (FUV) background has received considerable attention from astronomers since the 1970s The initial impetus came from the hope of detecting UV radiation from the hot intergalactic medium. The central importance of the FUV background to the physics (heating and ionization) of the diffuse atomic phases motivated the next generation of experiments. The consensus view is that the diffuse FUV emission at high latitudes has three components: stellar FUV reflected by dust grains (diffuse galactic light or DGL), FUV from other galaxies and the intergalactic medium (extra-galactic background light or EBL) and a component of unknown origin (and referred to as the “offset” component). During the 1980s, there was some discussion that decaying dark matter particles produced FUV radiation. In this paper I investigate production of FUV photons by conventional sources: line emission from Galactic Hot Ionized Medium, two-photon emission from the Galactic Warm Ionized Medium and low-velocity shocks, and Lyman- β fluorescence of hydrogen at several locales in the Solar System (the interplanetary medium, the exosphere and the thermosphere of Earth). I conclude that two thirds and arguably all of the offset component can be explained by the sum of the radiation from the processes listed above.

The impact of orthotropy on thermal displacement is useful to optimize thermal management systems in space structures. The thermal response of the beam is greatly affected by its aspect ratio. The expansion or contraction due to difference in coefficient of thermal expansion affects the structural integrity of the beam. An analytical model helps to understand the effect of these parameters on transverse thermal displacement of laminated beam. Hence, in the present work the effect of change of aspect ratio, degree of orthotropy and coefficient of thermal expansion ratio on transverse thermal displacement of orthotropic and cross ply laminated beams has been studied and presented. The trigonometric beam theory is used. The present theory has sine function in terms of thickness coordinate representing the shear deformation effect. The equations of motions are developed by using principle of virtual work. The transverse deflections are obtained by applying Navier’s solution. A computer program in FORTRAN-77 is developed to obtain transverse deflection for various aspect ratios, modular ratios and coefficient of thermal expansion ratios.

Intense, millisecond-duration bursts of radio waves (named fast radio bursts) have been detected from beyond the Milky Way 1 . Their dispersion measures—which are greater than would be expected if they had propagated only through the interstellar medium of the Milky Way—indicate extragalactic origins and imply contributions from the intergalactic medium and perhaps from other galaxies 2 . Although several theories exist regarding the sources of these fast radio bursts, their intensities, durations and temporal structures suggest coherent emission from highly magnetized plasma 3 , 4 . Two of these bursts have been observed to repeat 5 , 6 , and one repeater (FRB 121102) has been localized to the largest star-forming region of a dwarf galaxy at a cosmological redshift of 0.19 (refs. 7 – 9 ). However, the host galaxies and distances of the hitherto non-repeating fast radio bursts are yet to be identified. Unlike repeating sources, these events must be observed with an interferometer that has sufficient spatial resolution for arcsecond localization at the time of discovery. Here we report the localization of a fast radio burst (FRB 190523) to a few-arcsecond region containing a single massive galaxy at a redshift of 0.66. This galaxy is different from the host of FRB 121102, as it is a thousand times more massive, with a specific star-formation rate (the star-formation rate divided by the mass) a hundred times smaller. Use of a specially built radio interferometer shows that a non-repeating fast radio burst is localized to a few-arcsecond region containing a single massive galaxy, and is perhaps derived from an old stellar population.

The observed electromagnetic emission from GW170817 suggests that a ‘cocoon’ of mildly relativistic material was released as a jet transferred its energy to the neutron-rich dynamical ejecta from the merger. Radio waves reveal wide-angle outflow from merging stars On 17 August 2017, the detection of a gravitational-wave signature of merging neutron stars preceded that of a weak, short γ-ray burst. The source was quickly localized to the galaxy NGC 4993, and a range of telescopes measuring different parts of the electromagnetic spectrum followed the source, which was fading at most wavelengths. The radio emission, however, has continued to increase. Kunal Mooley and colleagues report continuing radio observations that are inconsistent with the off-axis relativistic jet that was initially believed to explain the optical, X-ray and γ-ray data. Instead, the radio data are best explained by a mildly relativistic wide-angle outflow. GW170817 was the first gravitational-wave detection of a binary neutron-star merger 1 . It was accompanied by radiation across the electromagnetic spectrum and localized 2 to the galaxy NGC 4993 at a distance of 40 megaparsecs. It has been proposed that the observed γ-ray, X-ray and radio emission is due to an ultra-relativistic jet being launched during the merger (and successfully breaking out of the surrounding material), directed away from our line of sight (off-axis) 3 , 4 , 5 , 6 . The presence of such a jet is predicted from models that posit neutron-star mergers as the drivers of short hard-γ-ray bursts 7 , 8 . Here we report that the radio light curve of GW170817 has no direct signature of the afterglow of an off-axis jet. Although we cannot completely rule out the existence of a jet directed away from the line of sight, the observed γ-ray emission could not have originated from such a jet. Instead, the radio data require the existence of a mildly relativistic wide-angle outflow moving towards us. This outflow could be the high-velocity tail of the neutron-rich material that was ejected dynamically during the merger, or a cocoon of material that breaks out when a jet launched during the merger transfers its energy to the dynamical ejecta. Because the cocoon model explains the radio light curve of GW170817, as well as the γ-ray and X-ray emission (and possibly also the ultraviolet and optical emission) 9 , 10 , 11 , 12 , 13 , 14 , 15 , it is the model that is most consistent with the observational data. Cocoons may be a ubiquitous phenomenon produced in neutron-star mergers, giving rise to a hitherto unidentified population of radio, ultraviolet, X-ray and γ-ray transients in the local Universe.

Since their discovery in 2007 1 , much effort has been devoted to uncovering the sources of the extragalactic, millisecond-duration fast radio bursts (FRBs) 2 . A class of neutron stars known as magnetars is a leading candidate source of FRBs 3 , 4 . Magnetars have surface magnetic fields in excess of 10 14 gauss, the decay of which powers a range of high-energy phenomena 5 . Here we report observations of a millisecond-duration radio burst from the Galactic magnetar SGR 1935+2154, with a fluence of 1.5 ± 0.3 megajansky milliseconds. This event, FRB 200428 (ST 200428A), was detected on 28 April 2020 by the STARE2 radio array 6 in the 1,281–1,468 megahertz band. The isotropic-equivalent energy released in FRB 200428 is 4 × 10 3 times greater than that of any radio pulse from the Crab pulsar—previously the source of the brightest Galactic radio bursts observed on similar timescales 7 . FRB 200428 is just 30 times less energetic than the weakest extragalactic FRB observed so far 8 , and is drawn from the same population as the observed FRB sample. The coincidence of FRB 200428 with an X-ray burst 9 – 11 favours emission models that describe synchrotron masers or electromagnetic pulses powered by magnetar bursts and giant flares 3 , 4 , 12 , 13 . The discovery of FRB 200428 implies that active magnetars such as SGR 1935+2154 can produce FRBs at extragalactic distances. Observations of the fast radio burst FRB 200428 coinciding with X-rays from the Galactic magnetar SGR 1935+2154 indicate that active magnetars can produce fast radio bursts at extragalactic distances.

Standard treatment for high-risk non-muscle-invasive bladder cancer is transurethral resection of bladder tumour followed by intravesical BCG immunotherapy. However, despite high initial responses rates, up to 50% of patients have recurrence or become BCG-unresponsive. PD-1 pathway activation is implicated in BCG resistance. In the KEYNOTE-057 study, we evaluated pembrolizumab, a PD-1 inhibitor, in BCG-unresponsive non-muscle-invasive bladder cancer. We did this open-label, single-arm, multicentre, phase 2 study in 54 sites (hospitals and cancer centres) in 14 countries. In cohort A of the trial, adults aged 18 years or older with histologically confirmed BCG-unresponsive carcinoma in situ of the bladder, with or without papillary tumours, with an Eastern Cooperative Oncology Group performance status of 0–2, and who were ineligible for or declined radical cystectomy were enrolled. All enrolled patients were assigned to receive pembrolizumab 200 mg intravenously every 3 weeks for up to 24 months or until centrally confirmed disease persistence, recurrence, or progression; unacceptable toxic effects; or withdrawal of consent. The primary endpoint was clinical complete response rate (absence of high-risk non-muscle-invasive bladder cancer or progressive disease), assessed by cystoscopy and urine cytology approximately 3 months after the first dose of study drug. Patient follow-ups were done every 3 months for the first 2 years and every 6 months thereafter for up to 5 years. Efficacy was assessed in all patients who received at least one dose of the study drug and met BCG-unresponsive criteria. Safety was assessed in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov number, NCT02625961, and is ongoing. Between Dec 9, 2015, and April 1, 2018, we screened 334 patients for inclusion. 186 patients did not meet inclusion criteria, and 47 patients were assigned to cohort B (patients with BCG-unresponsive high grade Ta or any grade T1 papillary disease without carcinoma in situ; results will be reported separately). 101 eligible patients were enrolled and assigned to receive pembrolizumab. All 101 patients received at least one dose of the study drug and were included in the safety analysis. Five patients had disease that did not meet the US Food and Drug Administration definition of BCG-unresponsive non-muscle-invasive bladder cancer and were therefore not included in the efficacy analysis (n=96). Median follow-up was 36·4 months (IQR 32·0–40·7). 39 (41%; 95% CI 30·7–51·1) of 96 patients with BCG-unresponsive carcinoma in situ of the bladder with or without papillary tumours had a complete response at 3 months. Grade 3 or 4 treatment-related adverse events occurred in 13 (13%) patients; the most common were arthralgia (in two [2%] patients) and hyponatraemia (in three [3%] patients). Serious treatment-related adverse events occurred in eight (8%) patients. There were no deaths that were considered treatment related. Pembrolizumab monotherapy was tolerable and showed promising antitumour activity in patients with BCG-unresponsive non-muscle-invasive bladder cancer who declined or were ineligible for radical cystectomy and should be considered a a clinically active non-surgical treatment option in this difficult-to-treat population. Merck Sharp & Dohme.

Despite the growing literature on subjective well-being (SWB), few studies have focused on developing countries. Applying robust OLS and ordered probit models to the India Human Development Survey panel data in 2005 and 2012, we empirically assess SWB changes in 2005–2012, based on a self-reported measure of changes in economic well-being, as a function of household and state covariates in 2005. This is in sharp contrast with earlier studies’ focus on the levels of SWB. Another point of departure of our study is to compare the covariates of SWB changes with those of objective well-being (OWB) changes, proxied by the relative growth in real per capita household consumption expenditure between 2005 and 2012, to identify specific micro-level correlates of SWB changes. Households with an older and educated head in a larger household, located in urban areas or affluent states in 2005 tend to experience improvement in both SWB and OWB between 2005 and 2012. In contrast, households with a female household head, with more male members in the labour market, with regular access to mass media, without members suffering from non-communicable diseases or disabilities are more likely to be better off subjectively without experiencing the corresponding improvement in OWB. The policy challenges raise serious concerns.

Although antibody-mediated lung damage is a major factor in transfusion-related acute lung injury (ALI), autoimmune lung disease (for example, coatomer subunit α [COPA] syndrome), and primary graft dysfunction following lung transplantation, the mechanism by which antigen-antibody complexes activate complement to induce lung damage remains unclear. In this issue of the JCI, Cleary and colleagues utilized several approaches to demonstrate that IgG forms hexamers with MHC class I alloantibodies. This hexamerization served as a key pathophysiological mechanism in alloimmune lung injury models and was mediated through the classical pathway of complement activation. Additionally, the authors provided avenues for exploring therapeutics for this currently hard-to-treat clinical entity that has several etiologies but a potentially focused mechanism.

Despite the growing popular interest in sleep and diet, many gaps exist in our scientific understanding of the interaction between circadian rhythms and metabolism. In this Review, we explore a promising, bidirectional role for ghrelin in mediating this interaction. Ghrelin both influences and is influenced by central and peripheral circadian systems. Specifically, we focus on how ghrelin impacts outputs of circadian rhythm, including neuronal activity, circulating growth hormone levels, locomotor activity and eating behaviour. We also consider the effects of circadian rhythms on ghrelin expression and the consequences of disrupted circadian patterns, such as shift work and jet lag, on ghrelin secretion. Our Review is aimed at both the casual reader interested in gaining more insight into the scientific context surrounding the trending topics of sleep and metabolism, as well as experienced scientists in the fields of ghrelin and circadian biology seeking inspiration and a comprehensive overview of how these fields are related. This Review describes a promising, bidirectional role for ghrelin in the interaction between circadian rhythms and metabolism. The authors explore how ghrelin affects outputs of circadian rhythm — including neuronal activity, circulating growth hormone levels, locomotor activity and eating behaviour — and discuss how circadian rhythms influence ghrelin expression. Key points Disrupted circadian and metabolic systems are a growing cause of societal health burden. The ghrelin system regulates many key metabolic functions including food intake, body weight, blood glucose, food anticipatory activity, growth hormone secretion and body temperature. Ghrelin and GHSR (growth hormone secretagogue receptor, which serves as the receptor for ghrelin) mRNA and protein expression are regulated by the circadian system. Ghrelin affects neuronal firing, food anticipatory activity and thermoregulation in a circadian-dependent manner. Given the expansion in scientific technology in the past 25 years, many more tools now exist to better understand the role of the ghrelin system in metabolism and circadian biology. Future studies are needed to elucidate further the connections between the ghrelin system, metabolism and circadian systems, and to provide novel avenues for therapeutic approaches.

General relativity 1 predicts that short-orbital-period binaries emit considerable amounts of gravitational radiation. The upcoming Laser Interferometer Space Antenna 2 (LISA) is expected to detect tens of thousands of such systems 3 but few have been identified 4 , of which only one 5 is eclipsing—the double-white-dwarf binary SDSS J065133.338+284423.37, which has an orbital period of 12.75 minutes. Here we report the discovery of an eclipsing double-white-dwarf binary system, ZTF J153932.16+502738.8, with an orbital period of 6.91 minutes. This system has an orbit so compact that the entire binary could fit within the diameter of the planet Saturn. The system exhibits a deep eclipse, and a double-lined spectroscopic nature. We see rapid orbital decay, consistent with that expected from general relativity. ZTF J153932.16+502738.8 is a strong source of gravitational radiation close to the peak of LISA’s sensitivity, and we expect it to be detected within the first week of LISA observations, once LISA launches in approximately 2034. Observations of an eclipsing double-white-dwarf binary with an orbital period of 6.91 minutes that is decaying as predicted by general relativity are reported; once launched, the Laser Interferometer Space Antenna (LISA) should swiftly detect this binary.