ABSTRACT
We utilize deep near-infrared survey data from the UltraVISTA fourth data release (DR4) and the VIDEO survey, in combination with overlapping optical and Spitzer data, to search for bright ...star-forming galaxies at z ≳ 7.5. Using a full photometric redshift fitting analysis applied to the ∼6 $\, {\rm deg}^2$ of imaging searched, we find 27 Lyman break galaxies (LBGs), including 20 new sources, with best-fitting photometric redshifts in the range 7.4 < z < 9.1. From this sample, we derive the rest-frame UV luminosity function at z = 8 and z = 9 out to extremely bright UV magnitudes (MUV ≃ −23) for the first time. We find an excess in the number density of bright galaxies in comparison to the typically assumed Schechter functional form derived from fainter samples. Combined with previous studies at lower redshift, our results show that there is little evolution in the number density of very bright (MUV ∼ −23) LBGs between z ≃ 5 and z ≃ 9. The tentative detection of an LBG with best-fitting photometric redshift of z = 10.9 ± 1.0 in our data is consistent with the derived evolution. We show that a double power-law fit with a brightening characteristic magnitude (ΔM*/Δz ≃ −0.5) and a steadily steepening bright-end slope (Δβ/Δz ≃ −0.5) provides a good description of the z > 5 data over a wide range in absolute UV magnitude (−23 < MUV < −17). We postulate that the observed evolution can be explained by a lack of mass quenching at very high redshifts in combination with increasing dust obscuration within the first ${\sim}1 \, {\rm Gyr}$ of galaxy evolution.
On 17 August 2017, Swope Supernova Survey 2017a (SSS17a) was discovered as the optical counterpart of the binary neutron star gravitational wave event GW170817. We report time-series spectroscopy of ...SSS17a from 11.75 hours until 8.5 days after the merger. Over the first hour of observations, the ejecta rapidly expanded and cooled. Applying blackbody fits to the spectra, we measured the photosphere cooling from
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kelvin, and determined a photospheric velocity of roughly 30% of the speed of light. The spectra of SSS17a began displaying broad features after 1.46 days and evolved qualitatively over each subsequent day, with distinct blue (early-time) and red (late-time) components. The late-time component is consistent with theoretical models of r-process–enriched neutron star ejecta, whereas the blue component requires high-velocity, lanthanide-free material.
ABSTRACT
We measure the rest-frame ultraviolet (UV) luminosity function (LF) at z ∼ 4 self-consistently over a wide range in absolute magnitude (−27 ≲ MUV ≲ −20). The LF is measured with 46 904 ...sources selected using a photometric redshift approach over ∼6 $\, {\rm deg}^2$ of the combined Cosmological Evolution Survey and XMM–Newton Large-Scale Structure fields. We simultaneously fit for both active galactic nuclei (AGNs) and galaxy LFs using a combination of Schechter or double power law (DPL) functions alongside a single power law for the faint-end slope of the AGN LF. We find a lack of evolution in the shape of the bright end of the Lyman-break galaxy (LBG) component when compared to other studies at z ≃ 5 and evolutionary recipes for the UV LF. Regardless of whether the LBG LF is fit with a Schechter function or DPL, AGNs are found to dominate at MUV < −23.5. We measure a steep faint-end slope of the AGN LF with $\alpha _{\mathrm{ AGN}} = -2.09^{+0.35}_{-0.38}$ ($-1.66^{+0.29}_{-0.58}$) when fit alongside a Schechter function (DPL) for the galaxies. Our results suggest that if AGNs are morphologically selected it results in a bias to lower number densities. Only by considering the full galaxy population over the transition region from AGN to LBG domination can an accurate measurement of the total LFs be attained.
Conservation conflicts are increasing and need to be managed to minimise negative impacts on biodiversity, human livelihoods, and human well-being. Here, we explore strategies and case studies that ...highlight the long-term, dynamic nature of conflicts and the challenges to their management. Conflict management requires parties to recognise problems as shared ones, and engage with clear goals, a transparent evidence base, and an awareness of trade-offs. We hypothesise that conservation outcomes will be less durable when conservationists assert their interests to the detriment of others. Effective conflict management and long-term conservation benefit will be enhanced by better integration of the underpinning social context with the material impacts and evaluation of the efficacy of alternative conflict management approaches.
On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope ...Supernova Survey 17a (SSS17a),was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe.
Summary
Libraries of 16S rRNA genes cloned from methanogenic oil degrading microcosms amended with North Sea crude oil and inoculated with estuarine sediment indicated that bacteria from the genera ...Smithella (Deltaproteobacteria, Syntrophaceace) and Marinobacter sp. (Gammaproteobacteria) were enriched during degradation. Growth yields and doubling times (36 days for both Smithella and Marinobacter) were determined using qPCR and quantitative data on alkanes, which were the predominant hydrocarbons degraded. The growth yield of the Smithella sp. 0.020 g(cell‐C)/g(alkane‐C), assuming it utilized all alkanes removed was consistent with yields of bacteria that degrade hydrocarbons and other organic compounds in methanogenic consortia. Over 450 days of incubation predominance and exponential growth of Smithella was coincident with alkane removal and exponential accumulation of methane. This growth is consistent with Smithella's occurrence in near surface anoxic hydrocarbon degrading systems and their complete oxidation of crude oil alkanes to acetate and/or hydrogen in syntrophic partnership with methanogens in such systems. The calculated growth yield of the Marinobacter sp., assuming it grew on alkanes, was 0.0005 g(cell‐C)/g(alkane‐C) suggesting that it played a minor role in alkane degradation. The dominant methanogens were hydrogenotrophs (Methanocalculus spp. from the Methanomicrobiales). Enrichment of hydrogen‐oxidizing methanogens relative to acetoclastic methanogens was consistent with syntrophic acetate oxidation measured in methanogenic crude oil degrading enrichment cultures. qPCR of the Methanomicrobiales indicated growth characteristics consistent with measured rates of methane production and growth in partnership with Smithella.
In this trial in nondiabetic patients with insulin resistance and a recent ischemic stroke or transient ischemic attack, pioglitazone was associated with a lower risk of stroke and MI than was ...placebo but with a higher risk of weight gain, edema, and bone fracture.
Ischemic stroke and transient ischemic attack (TIA) affect more than 14 million persons worldwide annually.
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Affected patients are at increased risk for future cardiovascular events,
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and prevention of these adverse outcomes is a major goal in their care.
Treatment of insulin resistance represents a potential new preventive strategy that could be added to standard care after ischemic stroke or TIA.
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Insulin resistance is nearly universal in patients with type 2 diabetes but is also present in more than 50% of patients without diabetes who have had an ischemic stroke or a TIA.
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The presence of insulin resistance increases . . .
The Combined Aerobic and Resistance Exercise Trial tested different types and doses of exercise in breast cancer patients receiving chemotherapy. Here, we explore potential moderators of the exercise ...training responses.
Breast cancer patients initiating chemotherapy (N=301) were randomly assigned to three times a week, supervised exercise of a standard dose of 25-30 min of aerobic exercise, a higher dose of 50-60 min of aerobic exercise, or a higher dose of 50-60 min of combined aerobic and resistance exercise. Outcomes were patient-reported symptoms and health-related fitness. Moderators were baseline demographic, exercise/fitness, and cancer variables.
Body mass index moderated the effects of the exercise interventions on bodily pain (P for interaction=0.038), endocrine symptoms (P for interaction=0.029), taxane/neuropathy symptoms (P for interaction=0.013), aerobic fitness (P for interaction=0.041), muscular strength (P for interaction=0.007), and fat mass (P for interaction=0.005). In general, healthy weight patients responded better to the higher-dose exercise interventions than overweight/obese patients. Menopausal status, age, and baseline fitness moderated the effects on patient-reported symptoms. Premenopausal, younger, and fitter patients achieved greater benefits from the higher-dose exercise interventions.
Healthy weight, fitter, and premenopausal/younger breast cancer patients receiving chemotherapy are more likely to benefit from higher-dose exercise interventions.
Coding variants in the apolipoprotein L1 gene (APOL1) are strongly associated with nephropathy in African Americans (AAs). The effect of transplanting kidneys from AA donors with two APOL1 ...nephropathy risk variants is unknown. APOL1 risk variants were genotyped in 106 AA deceased organ donors and graft survival assessed in 136 resultant kidney transplants. Cox‐proportional hazard models tested for association between time to graft failure and donor APOL1 genotypes. The mean follow‐up was 26.4 ± 21.8 months. Twenty‐two of 136 transplanted kidneys (16%) were from donors with two APOL1 nephropathy risk variants. Twenty‐five grafts failed; eight (32%) had two APOL1 risk variants. A multivariate model accounting for donor APOL1 genotype, overall African ancestry, expanded criteria donation, recipient age and gender, HLA mismatch, CIT and PRA revealed that graft survival was significantly shorter in donor kidneys with two APOL1 risk variants (hazard ratio HR 3.84; p = 0.008) and higher HLA mismatch (HR 1.52; p = 0.03), but not for overall African ancestry excluding APOL1. Kidneys from AA deceased donors harboring two APOL1 risk variants failed more rapidly after renal transplantation than those with zero or one risk variants. If replicated, APOL1 genotyping could improve the donor selection process and maximize long‐term renal allograft survival.
Renal allograft survival was shorter in patients receiving deceased donor kidneys from African Americans with two, compared to zero or one, APOL1 nephropathy risk variants.
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