5,633 research outputs found

    The LIL for UU-statistics in Hilbert spaces

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    We give necessary and sufficient conditions for the (bounded) law of the iterated logarithm for UU-statistics in Hilbert spaces. As a tool we also develop moment and tail estimates for canonical Hilbert-space valued UU-statistics of arbitrary order, which are of independent interest

    Constraints on dark energy models from radial baryon acoustic scale measurements

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    We use the radial baryon acoustic oscillation (BAO) measurements of Gaztanaga et al. (2008) to constrain parameters of dark energy models. These constraints are comparable with constraints from other "non-radial" BAO data. The radial BAO data are consistent with the time-independent cosmological constant model but do not rule out time-varying dark energy. When we combine radial BAO and the Kowalski et al. (2008) Union type Ia supernova data we get very tight constraints on dark energy.Comment: 24 pages, 8 figures, 1 table. Minor changes to match the published versio

    Specific lid-base contacts in the 26s proteasome control the conformational switching required for substrate degradation.

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    The 26S proteasome is essential for proteostasis and the regulation of vital processes through ATP-dependent degradation of ubiquitinated substrates. To accomplish the multi-step degradation process, the proteasomes regulatory particle, consisting of lid and base subcomplexes, undergoes major conformational changes whose origin is unknown. Investigating the Saccharomyces cerevisiae proteasome, we found that peripheral interactions between the lid subunit Rpn5 and the base AAA+ ATPase ring are important for stabilizing the substrate-engagement-competent state and coordinating the conformational switch to processing states upon substrate engagement. Disrupting these interactions perturbs the conformational equilibrium and interferes with degradation initiation, while later processing steps remain unaffected. Similar defects in early degradation steps are observed when eliminating hydrolysis in the ATPase subunit Rpt6, whose nucleotide state seems to control proteasome conformational transitions. These results provide important insight into interaction networks that coordinate conformational changes with various stages of degradation, and how modulators of conformational equilibria may influence substrate turnover

    Determining Quasar Black Hole Mass Functions from their Broad Emission Lines: Application to the Bright Quasar Survey

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    We describe a Bayesian approach to estimating quasar black hole mass functions (BHMF) when using the broad emission lines to estimate black hole mass. We show how using the broad line mass estimates in combination with statistical techniques developed for luminosity function estimation leads to statistically biased results. We derive the likelihood function for the BHMF based on the broad line mass estimates, and derive the posterior distribution for the BHMF, given the observed data. We develop our statistical approach for a flexible model where the BHMF is modelled as a mixture of Gaussian functions. Statistical inference is performed using markov chain monte carlo (MCMC) methods. Our method has the advantage that it is able to constrain the BHMF even beyond the survey detection limits at the adopted confidence level, accounts for measurement errors and the intrinsic uncertainty in broad line mass estimates, and provides a natural way of estimating the probability distribution of any quantities derived from the BHMF. We conclude by using our method to estimate the local active BHMF using the z < 0.5 Bright Quasar Survey sources. At z = 0.2, the quasar BHMF falls off approximately as a power law with slope ~ 2 for M_{BH} > 10^8. Our analysis implies that z < 0.5 broad line quasars have a typical Eddington ratio of ~ 0.4 and a dispersion in Eddington ratio of < 0.5 dex (abridged).Comment: 25 pages, 14 figures, emulate ApJ style, accepted by Ap

    Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging of a Growing Compact Galaxy at z=1.9

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    We present HST/WFC3 grism spectroscopy of the brightest galaxy at z>1.5 in the GOODS-South WFC3 Early Release Science grism pointing, covering the wavelength range 0.9-1.7 micron. The spectrum is of remarkable quality and shows the redshifted Balmer lines Hbeta, Hgamma, and Hdelta in absorption at z=1.902, correcting previous erroneous redshift measurements from the rest-frame UV. The average rest-frame equivalent width of the Balmer lines is 8+-1 Angstrom, which can be produced by a post-starburst stellar population with a luminosity-weighted age of ~0.5 Gyr. The M/L ratio inferred from the spectrum implies a stellar mass of ~4x10^11 Msun. We determine the morphology of the galaxy from a deep WFC3 F160W image. Similar to other massive galaxies at z~2 the galaxy is compact, with an effective radius of 2.1+-0.3 kpc. Although most of the light is in a compact core, the galaxy has two red, smooth spiral arms that appear to be tidally-induced. The spatially-resolved spectroscopy demonstrates that the center of the galaxy is quiescent and the surrounding disk is forming stars, as it shows Hbeta in emission. The galaxy is interacting with a companion at a projected distance of 18 kpc, which also shows prominent tidal features. The companion has a slightly redder spectrum than the primary galaxy but is a factor of ~10 fainter and may have a lower metallicity. It is tempting to interpret these observations as "smoking gun" evidence for the growth of compact, quiescent high redshift galaxies through minor mergers, which has been proposed by several recent observational and theoretical studies. Interestingly both objects host luminous AGNs, as indicated by their X-ray luminosities, which implies that these mergers can be accompanied by significant black hole growth. This study illustrates the power of moderate dispersion, low background near-IR spectroscopy at HST resolution, which is now available with the WFC3 grism.Comment: 5 pages, 5 figures. Submitted to ApJ Letters

    Ages and Metallicities of Hickson Compact Group Galaxies

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    Hickson Compact Groups (HCGs) constitute an interesting extreme in the range of environments in which galaxies are located, as the space density of galaxies in these small groups are otherwise only found in the centres of much larger clusters. The work presented here uses Lick indices to make a comparison of ages and chemical compositions of galaxies in HCGs with those in other environments (clusters, loose groups and the field). The metallicity and relative abundance of `α\alpha-elements' show strong correlations with galaxy age and central velocity dispersion, with similar trends found in all environments. However, we show that the previously reported correlation between α\alpha-element abundance ratios and velocity dispersion disappears when a full account is taken of the the abundance ratio pattern in the calibration stars. This correlation is thus found to be an artifact of incomplete calibration to the Lick system. Variations are seen in the ranges and average values of age, metallicity and α\alpha-element abundance ratios for galaxies in different environments. Age distributions support the hierarchical formation prediction that field galaxies are on average younger than their cluster counterparts. However, the ages of HCG galaxies are shown to be more similar to those of cluster galaxies than those in the field, contrary to the expectations of current hierarchical models. A trend for lower velocity dispersion galaxies to be younger was also seen. This is again inconsistent with hierarchical collapse models, but is qualitatively consistent with the latest N-body-SPH models based on monolithic collapse in which star formation continues for many Gyr in low mass halos.Comment: 18 pages. Submitted for publication in MNRA

    XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U1700-37 at low flux

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    We present results of a monitoring campaign of the high-mass X-ray binary system 4U 1700-37/HD 153919, carried out with XMM-Newton in February 2001. The system was observed at four orbital phase intervals, covering 37% of one 3.41-day orbit. The lightcurve includes strong flares, commonly observed in this source. We focus on three epochs in which the data are not affected by photon pile up: the eclipse, the eclipse egress and a low-flux interval in the lightcurve around orbital phase phi ~0.25. The high-energy part of the continuum is modelled as a direct plus a scattered component, each represented by a power law with identical photon index (alpha ~1.4), but with different absorption columns. We show that during the low-flux interval the continuum is strongly reduced, probably due to a reduction of the accretion rate onto the compact object. A soft excess is detected in all spectra, consistent with either another continuum component originating in the outskirts of the system or a blend of emission lines. Many fluorescence emission lines from near-neutral species and discrete recombination lines from He- and H-like species are detected during eclipse and egress. The detection of recombination lines during eclipse indicates the presence of an extended ionised region surrounding the compact object. The observed increase in strength of some emission lines corresponding to higher values of the ionisation parameter xi further substantiates this conclusion.Comment: 15 pages, 7 figures, accepted for publication in Astronomy and Astrophysic

    Accuracy of magnetic resonance studies in the detection of chondral and labral lesions in femoroacetabular impingement : systematic review and meta-analysis

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    Background: Several types of Magnetic resonance imaging (MRI) are commonly used in imaging of femoroacetabular impingement (FAI), however till now there are no clear protocols and recommendations for each type. The aim of this meta-analysis is to detect the accuracy of conventional magnetic resonance imaging (cMRI), direct magnetic resonance arthrography (dMRA) and indirect magnetic resonance arthrography (iMRA) in the diagnosis of chondral and labral lesions in femoroacetabular impingement (FAI). Methods: A literature search was finalized on the 17th of May 2016 to collect all studies identifying the accuracy of cMRI, dMRA and iMRA in diagnosing chondral and labral lesions associated with FAI using surgical results (arthroscopic or open) as a reference test. Pooled sensitivity and specificity with 95% confidence intervals using a random-effects meta-analysis for MRI, dMRA and iMRA were calculated also area under receiver operating characteristic (ROC) curve (AUC) was retrieved whenever possible where AUC is equivocal to diagnostic accuracy. Results: The search yielded 192 publications which were reviewed according inclusion and exclusion criteria then 21 studies fulfilled the eligibility criteria for the qualitative analysis with a total number of 828 cases, lastly 12 studies were included in the quantitative meta-analysis. Meta-analysis showed that as regard labral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.864, 0.833 and 0.88 and for dMRA were 0.91, 0.58 and 0.92. While in chondral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.76, 0.72 and 0.75 and for dMRA were 0.75, 0.79 and 0.83, while for iMRA were sensitivity of 0.722 and specificity of 0.917. Conclusions: The present meta-analysis showed that the diagnostic test accuracy was superior for dMRA when compared with cMRI for detection of labral and chondral lesions. The diagnostic test accuracy was superior for labral lesions when compared with chondral lesions in both cMRI and dMRA. Promising results are obtained concerning iMRA but further studies still needed to fully assess its diagnostic accuracy

    Brans-Dicke Theory and primordial black holes in Early Matter-Dominated Era

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    We show that primordial black holes can be formed in the matter-dominated era with gravity described by the Brans-Dicke theory. Considering an early matter-dominated era between inflation and reheating, we found that the primordial black holes formed during that era evaporate at a quicker than those of early radiation-dominated era. Thus, in comparison with latter case, less number of primordial black holes could exist today. Again the constraints on primordial black hole formation tend towards the larger value than their radiation-dominated era counterparts indicating a significant enhancement in the formation of primordial black holes during the matter-dominaed era.Comment: 9 page

    Efficacy and safety of enzyme replacement therapy with BMN 110 (elosulfase alfa) for Morquio A syndrome (mucopolysaccharidosis IVA): a phase 3 randomised placebo-controlled study.

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    ObjectiveTo assess the efficacy and safety of enzyme replacement therapy (ERT) with BMN 110 (elosulfase alfa) in patients with Morquio A syndrome (mucopolysaccharidosis IVA).MethodsPatients with Morquio A aged ≥5&nbsp;years (N = 176) were randomised (1:1:1) to receive elosulfase alfa 2.0&nbsp;mg/kg/every other week (qow), elosulfase alfa 2.0&nbsp;mg/kg/week (weekly) or placebo for 24&nbsp;weeks in this phase 3, double-blind, randomised study. The primary efficacy measure was 6-min walk test (6MWT) distance. Secondary efficacy measures were 3-min stair climb test (3MSCT) followed by change in urine keratan sulfate (KS). Various exploratory measures included respiratory function tests. Patient safety was also evaluated.ResultsAt week 24, the estimated mean effect on the 6MWT versus placebo was 22.5 m (95&nbsp;% CI 4.0, 40.9; P = 0.017) for weekly and 0.5 m (95&nbsp;% CI -17.8, 18.9; P = 0.954) for qow. The estimated mean effect on 3MSCT was 1.1 stairs/min (95&nbsp;% CI -2.1, 4.4; P = 0.494) for weekly and -0.5 stairs/min (95&nbsp;% CI -3.7, 2.8; P = 0.778) for qow. Normalised urine KS was reduced at 24&nbsp;weeks in both regimens. In the weekly dose group, 22.4&nbsp;% of patients had adverse events leading to an infusion interruption/discontinuation requiring medical intervention (only 1.3&nbsp;% of all infusions in this group) over 6&nbsp;months. No adverse events led to permanent treatment discontinuation.ConclusionsElosulfase alfa improved endurance as measured by the 6MWT in the weekly but not qow dose group, did not improve endurance on the 3MSCT, reduced urine KS, and had an acceptable safety profile
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