We present two luminous UV/optical flares from the nuclei of apparently inactive early-type galaxies at image and 0.33 that have the radiative properties of a flare from the tidal disruption of a ...star. In this paper we report the second candidate tidal disruption event discovery in the UV by the GALEX Deep Imaging Survey and present simultaneous optical light curves from the CFHTLS Deep Imaging Survey for both UV flares. The first few months of the UV/optical light curves are well fitted with the canonical image power-law decay predicted for emission from the fallback of debris from a tidally disrupted star. Chandra ACIS X-ray observations during the flares detect soft X-ray sources with image or image and place limits on hard X- ray emission from an underlying AGN down to image. Blackbody fits to the UV/optical spectral energy distributions of the flares indicate peak flare luminosities of image10 super(44)-10 super(45) ergs s super(-1). The temperature, luminosity, and light curves of both flares are in excellent agreement with emission from a tidally disrupted main-sequence star onto a central black hole of several times 10 super(7) M sub(image). The observed detection rate of our search over image2.9 deg super( 2) of GALEX Deep Imaging Survey data spanning from 2003 to 2007 is consistent with tidal disruption rates calculated from dynamical models, and we use these models to make predictions for the detection rates of the next generation of optical synoptic surveys.
A supermassive black hole in the nucleus of a galaxy will be revealed when a star passes close enough to be torn apart by tidal forces and a flare of radiation is emitted by the stream of stellar ...debris that plunges into the black hole. Since common active galactic nuclei have accreting black holes that can also produce flares, a convincing demonstration that a stellar tidal disruption has occurred generally begins with a "normal" galaxy that has no evidence of prior nuclear activity. Here we report a luminous UV flare from an elliptical galaxy at z = 0.37 in the Groth field of the GALEX Deep Imaging Survey that has no evidence of a Seyfert nucleus from optical spectroscopy and X-ray imaging obtained during the flare. Multiwavelength data collected at the time of the event, and for 2 years following, allow us to constrain, for the first time, the spectral energy distribution of a candidate tidal disruption flare from optical through X-rays. The luminosity and temperature of the radiation and the decay curve of the flare are in excellent agreement with theoretical predictions for the tidal disruption of a star, and provide the strongest empirical evidence for a stellar disruption event to date.
We have studied similar to 2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range 0 < z < 0.11. Combining GALEX UV ...photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, at least similar to 30% of galaxies in this sample have UV to optical colors consistent with some recent star formation within the last Gyr. In particular, galaxies with an NUV - r color less than 5.5 are very likely to have experienced such recent star formation, taking into account the possibility of a contribution to NUV flux from the UV upturn phenomenon. We find quantitative agreement between the observations and the predictions of a semianalytical Lambda CDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < z < 0.11 have similar to 1%-3% of their stellar mass in stars less than 1 Gyr old. The average age of this recently formed population is similar to 300-500 Myr. We also find that "monolithically" evolving galaxies, where recent star formation can be driven solely by recycled gas from stellar mass loss, cannot exhibit the blue colors (NUV - r < 5.5) seen in a significant fraction ( similar to 30%) of our observed sample.
We use GALEX near-UV (NUV) photometry of a sample of early-type galaxies selected in the SDSS (Sloan Digital Sky Survey) to study the UV color-magnitude relation (CMR). NUV - r color is an excellent ...tracer of even small amounts ( similar to 1% mass fraction) of recent ( unk1 Gyr) star formation, and so the NUV - r CMR allows us to study the effect of environment on the recent star formation history. We analyze a volume-limited sample of 839 visually inspected early-type galaxies in the redshift range 0.05 < z < 0.10 brighter than M sub(r) of -21.5 with any possible emission-line or radio-selected active galactic nuclei (AGNs) removed to avoid contamination. We find that contamination by AGN candidates and late-type interlopers highly bias any study of recent star formation in early-type galaxies and that, after removing those, our lower limit to the fraction of massive early-type galaxies showing signs of recent star formation is roughly 30% plus or minus 3%. This suggests that residual star formation is common even among the present day early-type galaxy population. We find that the fraction of UV-bright early-type galaxies is 25% higher in low-density environments. However, the density effect is clear only in the lowest density bin. The blue galaxy fraction for the subsample of the brightest early-type galaxies, however, shows a very strong density dependence, in the sense that the blue galaxy fraction is lower in a higher density region.
We sought to optimize a method for quantification of the calcium in the aortic-valvar complex for the prediction of significant paravalvular leak (PVL) after transcatheter aortic valve implantation ...(TAVI).
All patients had severe symptomatic aortic stenosis and were treated with balloon-expandable TAVI (Sapien/Sapien-XT, Edwards Lifesciences LLC, Irvine, CA, USA). In order to correct for precise annular sizing, only patients with available contrast computed tomography (CT) data for measurements were included (n = 198). Paravalvular leak was quantified using peri-procedural transoesophageal echocardiography by Valve Academic Research Consortium-2 (VARC-2) criteria (grade ≥ moderate was considered significant). A detailed region-of-interest methodology separated quantification of calcium in each of the aortic leaflets to that in the left ventricular outflow tract (LVOT) and was used to predict PVL in receiver operator characteristic curve analyses. For non-contrast scans, the greatest discriminatory value for PVL was seen at the 450 Hounsfield Unit (HU) threshold for detection (volume ≥626 mm(3)), whereas for contrast scans it was at 850 HU (≥235 mm(3)). Left ventricular outflow tract calcium predicted PVL but only as a binary variable with no incremental value of quantification. In a multivariable binary logistic regression model, annulus area ≥ prosthesis area (OR 3.5, 95% CI 1.5-8.2, P = 0.005), contrast leaflet calcium volume (850-HU threshold) ≥235 mm(3) (OR 2.8, 95% CI 1.2-6.7, P = 0.023), and presence of LVOT calcium (OR 2.8, 95% CI 1.2-7.0, P = 0.022) were independent predictors for PVL ≥ moderate.
Both leaflet and LVOT calcium are significant predictors of PVL and exert an important synergistic influence on this complication, even in appropriately sized valves. With careful attention to thresholds for detection, clinically relevant leaflet calcium volumes can be identified with either non-contrast or contrast CT scans.
We compare the dust attenuation properties of two samples of galaxies purely selected in the Galaxy Evolution Explorer (GALEX) near-ultraviolet band (NUV; 1750-2750 Å, λmean=2310 Å) and in the ...far-infrared (FIR) at 60 μm. These samples are built using the GALEX and IRAS sky surveys over ~600 deg2. The NUV-selected sample contains 95 galaxies detected down to NUV=16 mag (AB system). Eighty-three galaxies in this sample are spiral or irregular, and only two of them are not detected at 60 μm. The FIR-selected sample is built from the IRAS PSCz survey, which is complete down to 0.6 Jy. Among the 163 sources, we select 118 star-forming galaxies that are well measured by IRAS; all but one are detected in NUV, and 14 galaxies are not detected in the far-ultraviolet band (FUV; 1350-1750 Å, λmean=1530 Å). The dust-to-ultraviolet (NUV and FUV) flux ratio is calibrated to estimate the dust attenuation at both wavelengths. The median value of the attenuation in NUV is found to be ~1 mag for the NUV-selected sample, versus ~2 mag for the FIR-selected one. Within both samples, the dust attenuation is found to correlate with the luminosity of the galaxies. Almost all the NUV-selected galaxies and two-thirds of the FIR-selected sample exhibit a lower dust attenuation than expected from the tight relation found previously for starburst galaxies between dust attenuation and the slope of the ultraviolet continuum. The situation is reversed for the remaining third of the FIR-selected galaxies: their extinction is higher than that deduced from their FUV-NUV color and the relation for starbursts.
Nonalcoholic steatohepatitis (NASH), a chronic liver disease without an approved therapy, is associated with lipotoxicity and insulin resistance and is a major cause of cirrhosis and hepatocellular ...carcinoma. Aramchol, a partial inhibitor of hepatic stearoyl-CoA desaturase (SCD1) improved steatohepatitis and fibrosis in rodents and reduced steatosis in an early clinical trial. ARREST, a 52-week, double-blind, placebo-controlled, phase 2b trial randomized 247 patients with NASH (n = 101, n = 98 and n = 48 in the Aramchol 400 mg, 600 mg and placebo arms, respectively; NCT02279524 ). The primary end point was a decrease in hepatic triglycerides by magnetic resonance spectroscopy at 52 weeks with a dose of 600 mg of Aramchol. Key secondary end points included liver histology and alanine aminotransferase (ALT). Aramchol 600 mg produced a placebo-corrected decrease in liver triglycerides without meeting the prespecified significance (-3.1, 95% confidence interval (CI) -6.4 to 0.2, P = 0.066), precluding further formal statistical analysis. NASH resolution without worsening fibrosis was achieved in 16.7% (13 out of 78) of Aramchol 600 mg versus 5% (2 out of 40) of the placebo arm (odds ratio (OR) = 4.74, 95% CI = 0.99 to 22.7) and fibrosis improvement by ≥1 stage without worsening NASH in 29.5% versus 17.5% (OR = 1.88, 95% CI = 0.7 to 5.0), respectively. The placebo-corrected decrease in ALT for 600 mg was -29.1 IU l
(95% CI = -41.6 to -16.5). Early termination due to adverse events (AEs) was <5%, and Aramchol 600 and 400 mg were safe, well tolerated and without imbalance in serious or severe AEs between arms. Although the primary end point of a reduction in liver fat did not meet the prespecified significance level with Aramchol 600 mg, the observed safety and changes in liver histology and enzymes provide a rationale for SCD1 modulation as a promising therapy for NASH and fibrosis and are being evaluated in an ongoing phase 3 program.
Immersion‐mode ice‐nucleating particle (INP) concentrations from an off‐road diesel engine were measured using a continuous‐flow diffusion chamber at −30°C. Both petrodiesel and biodiesel were ...utilized, and the exhaust was aged up to 1.5 photochemically equivalent days using an oxidative flow reactor. We found that aged and unaged diesel exhaust of both fuels is not likely to contribute to atmospheric INP concentrations at mixed‐phase cloud conditions. To explore this further, a new limit‐of‐detection parameterization for ice nucleation on diesel exhaust was developed. Using a global‐chemical transport model, potential black carbon INP (INPBC) concentrations were determined using a current literature INPBC parameterization and the limit‐of‐detection parameterization. Model outputs indicate that the current literature parameterization likely overemphasizes INPBC concentrations, especially in the Northern Hemisphere. These results highlight the need to integrate new INPBC parameterizations into global climate models as generalized INPBC parameterizations are not valid for diesel exhaust.
Key Points
Diesel and biodiesel exhaust do not produce significant ice‐nucleating particle concentrations
Photochemical aging does not increase ice‐nucleating particle concentrations in diesel exhaust
Current parameterizations may overemphasize black carbon ice‐nucleating particle concentrations globally
We present an improved analysis of the final data set from the QUaD experiment. Using an improved technique to remove ground contamination, we double the effective sky area and hence increase the ...precision of our cosmic microwave background (CMB) power spectrum measurements by ~30% versus that previously reported. In addition, we have improved our modeling of the instrument beams and have reduced our absolute calibration uncertainty from 5% to 3.5% in temperature. The robustness of our results is confirmed through extensive jackknife tests, and by way of the agreement that we find between our two fully independent analysis pipelines. For the standard six-parameter Delta *LCDM model, the addition of QUaD data marginally improves the constraints on a number of cosmological parameters over those obtained from the WMAP experiment alone. The impact of QUaD data is significantly greater for a model extended to include either a running in the scalar spectral index, or a possible tensor component, or both. Adding both the QUaD data and the results from the Arcminute Cosmology Bolometer Array Receiver experiment, the uncertainty in the spectral index running is reduced by ~25% compared to WMAP alone, while the upper limit on the tensor-to-scalar ratio is reduced from r < 0.48 to r < 0.33 (95% c.l.). This is the strongest limit on tensors to date from the CMB alone. We also use our polarization measurements to place constraints on parity-violating interactions to the surface of last scattering, constraining the energy scale of Lorentz violating interactions to <1.5 X 10-43 GeV (68% c.l.). Finally, we place a robust upper limit on the strength of the lensing B-mode signal. Assuming a single flat band power between = 200 and = 2000, we constrain the amplitude of B-modes to be <0.57 Delta *mK2 (95% c.l.).
Chronic pancreatitis is a potentially life-threatening disease
1
; the most common types are alcohol related and idiopathic. Susceptibility to pancreatitis varies widely.
2
Even though pancreatitis ...rarely results from recognized genetic defects,
3
,
4
it is unknown whether hereditary factors increase the likelihood of the two predominant forms.
The most common inherited disease of the exocrine pancreas is cystic fibrosis.
5
–
8
In cystic fibrosis, mutations of the cystic fibrosis transmembrane conductance regulator (
CF TR
) gene lead to dysfunction of the lung, sweat glands, vas deferens, and pancreas. Lung disease accounts for most of the complications and deaths related to cystic . . .
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