Pre-main-sequence isochrones - III: The Cluster Collaboration isochrone server

We present an isochrone server for semi-empirical pre-main-sequence model isochrones in the following systems: Johnson–Cousins, Sloan Digital Sky Survey, Two-Micron All-Sky Survey, Isaac Newton Telescope (INT) Wide-Field Camera and INT Photometric Hα Survey (IPHAS)/UV-Excess Survey (UVEX). The server can be accessed via the Cluster Collaboration webpage http://www.astro.ex.ac.uk/people/timn/isochrones/. To achieve this, we have used the observed colours of member stars in young clusters with well-established age, distance and reddening to create fiducial loci in the colour–magnitude diagram. These empirical sequences have been used to quantify the discrepancy between the models and data arising from uncertainties in both the interior and atmospheric models, resulting in tables of semi-empirical bolometric corrections (BCs) in the various photometric systems. The model isochrones made available through the server are based on existing stellar interior models coupled with our newly derived semi-empirical BCs. As part of this analysis, we also present new cluster parameters for both the Pleiades and Praesepe, yielding ages of 135+20−11 and 665+14−7Myr as well as distances of 132 ± 2 and 184 ± 2 pc, respectively (statistical uncertainty only)

Pre-main-sequence isochrones - III. The cluster collaboration isochrone server

We present an isochrone server for semi-empirical pre-main-sequence model isochrones in the following systems: Johnson-Cousins, Sloan Digital Sky Survey, Two-Micron All-Sky Survey, Isaac Newton Telescope (INT) Wide-Field Camera and INT Photometric Ha Survey (IPHAS)/UV-Excess Survey (UVEX). The server can be accessed via the Cluster Collaboration webpage http://www.astro.ex.ac.uk/people/timn/isochrones/. To achieve this, we have used the observed colours ofmember stars in young clusters with well-established age, distance and reddening to create fiducial loci in the colour-magnitude diagram. These empirical sequences have been used to quantify the discrepancy between the models and data arising from uncertainties in both the interior and atmospheric models, resulting in tables of semi-empirical bolometric corrections (BCs) in the various photometric systems. The model isochrones made available through the server are based on existing stellar interior models coupled with our newly derived semi-empirical BCs. As part of this analysis, we also present new cluster parameters for both the Pleiades and Praesepe, yielding ages of 135+20 -11 and 665+14 -7 Myr as well as distances of 132 ± 2 and 184 ± 2 pc, respectively (statistical uncertainty only).JMR is funded by a UK Science and Technology Facilities Council (STFC) studentship. EEM acknowledges support from the National Science Foundation (NSF) Award AST-1008908. The authors would like to thank Emanuele Tognelli for the updated set of Pisa models and John Stauffer for sharing his catalogue of Kron photometric measurements of Pleiades members. The authors would also like to thank the referee for comments which have vastly improved the clarity of the manuscript. This research has made use of data obtained at the Isaac Newton Telescope, which is operated on the island of La Palma by the Isaac Newton Group (ING) in the Spanish Observatorio del Roque de los Muchachos of the Institutio de Astrofisica de Canarias. This research has made use of archival data products from the Two-Micron All-Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration (NASA) and the National Science Foundation. This research has made use of public data from the SDSS. Funding for the SDSS was provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society and the Higher Education Funding Council for England. The SDSS was managed by the Astrophysical Research Consortium for the Participating Institutions

Carboxyhaemoglobin levels and their determinants in older British men

Background: Although there has been concern about the levels of carbon monoxide exposure, particularly among older people, little is known about COHb levels and their determinants in the general population. We examined these issues in a study of older British men.Methods: Cross-sectional study of 4252 men aged 60-79 years selected from one socially representative general practice in each of 24 British towns and who attended for examination between 1998 and 2000. Blood samples were measured for COHb and information on social, household and individual factors assessed by questionnaire. Analyses were based on 3603 men measured in or close to (< 10 miles) their place of residence.Results: The COHb distribution was positively skewed. Geometric mean COHb level was 0.46% and the median 0.50%; 9.2% of men had a COHb level of 2.5% or more and 0.1% of subjects had a level of 7.5% or more. Factors which were independently related to mean COHb level included season (highest in autumn and winter), region (highest in Northern England), gas cooking (slight increase) and central heating (slight decrease) and active smoking, the strongest determinant. Mean COHb levels were more than ten times greater in men smoking more than 20 cigarettes a day (3.29%) compared with non-smokers (0.32%); almost all subjects with COHb levels of 2.5% and above were smokers (93%). Pipe and cigar smoking was associated with more modest increases in COHb level. Passive cigarette smoking exposure had no independent association with COHb after adjustment for other factors. Active smoking accounted for 41% of variance in COHb level and all factors together for 47%.Conclusion: An appreciable proportion of men have COHb levels of 2.5% or more at which symptomatic effects may occur, though very high levels are uncommon. The results confirm that smoking (particularly cigarette smoking) is the dominant influence on COHb levels

Random Numbers Certified by Bell's Theorem

Randomness is a fundamental feature in nature and a valuable resource for applications ranging from cryptography and gambling to numerical simulation of physical and biological systems. Random numbers, however, are difficult to characterize mathematically, and their generation must rely on an unpredictable physical process. Inaccuracies in the theoretical modelling of such processes or failures of the devices, possibly due to adversarial attacks, limit the reliability of random number generators in ways that are difficult to control and detect. Here, inspired by earlier work on nonlocality based and device independent quantum information processing, we show that the nonlocal correlations of entangled quantum particles can be used to certify the presence of genuine randomness. It is thereby possible to design of a new type of cryptographically secure random number generator which does not require any assumption on the internal working of the devices. This strong form of randomness generation is impossible classically and possible in quantum systems only if certified by a Bell inequality violation. We carry out a proof-of-concept demonstration of this proposal in a system of two entangled atoms separated by approximately 1 meter. The observed Bell inequality violation, featuring near-perfect detection efficiency, guarantees that 42 new random numbers are generated with 99% confidence. Our results lay the groundwork for future device-independent quantum information experiments and for addressing fundamental issues raised by the intrinsic randomness of quantum theory.Comment: 10 pages, 3 figures, 16 page appendix. Version as close as possible to the published version following the terms of the journa

Logopenic and nonfluent variants of primary progressive aphasia are differentiated by acoustic measures of speech production

Differentiation of logopenic (lvPPA) and nonfluent/agrammatic (nfvPPA) variants of Primary Progressive Aphasia is important yet remains challenging since it hinges on expert based evaluation of speech and language production. In this study acoustic measures of speech in conjunction with voxel-based morphometry were used to determine the success of the measures as an adjunct to diagnosis and to explore the neural basis of apraxia of speech in nfvPPA. Forty-one patients (21 lvPPA, 20 nfvPPA) were recruited from a consecutive sample with suspected frontotemporal dementia. Patients were diagnosed using the current gold-standard of expert perceptual judgment, based on presence/absence of particular speech features during speaking tasks. Seventeen healthy age-matched adults served as controls. MRI scans were available for 11 control and 37 PPA cases; 23 of the PPA cases underwent amyloid ligand PET imaging. Measures, corresponding to perceptual features of apraxia of speech, were periods of silence during reading and relative vowel duration and intensity in polysyllable word repetition. Discriminant function analyses revealed that a measure of relative vowel duration differentiated nfvPPA cases from both control and lvPPA cases (r2 = 0.47) with 88% agreement with expert judgment of presence of apraxia of speech in nfvPPA cases. VBM analysis showed that relative vowel duration covaried with grey matter intensity in areas critical for speech motor planning and programming: precentral gyrus, supplementary motor area and inferior frontal gyrus bilaterally, only affected in the nfvPPA group. This bilateral involvement of frontal speech networks in nfvPPA potentially affects access to compensatory mechanisms involving right hemisphere homologues. Measures of silences during reading also discriminated the PPA and control groups, but did not increase predictive accuracy. Findings suggest that a measure of relative vowel duration from of a polysyllable word repetition task may be sufficient for detecting most cases of apraxia of speech and distinguishing between nfvPPA and lvPPA

Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km

For more than 80 years, the counterintuitive predictions of quantum theory have stimulated debate about the nature of reality. In his seminal work, John Bell proved that no theory of nature that obeys locality and realism can reproduce all the predictions of quantum theory. Bell showed that in any local realist theory the correlations between distant measurements satisfy an inequality and, moreover, that this inequality can be violated according to quantum theory. This provided a recipe for experimental tests of the fundamental principles underlying the laws of nature. In the past decades, numerous ingenious Bell inequality tests have been reported. However, because of experimental limitations, all experiments to date required additional assumptions to obtain a contradiction with local realism, resulting in loopholes. Here we report on a Bell experiment that is free of any such additional assumption and thus directly tests the principles underlying Bell's inequality. We employ an event-ready scheme that enables the generation of high-fidelity entanglement between distant electron spins. Efficient spin readout avoids the fair sampling assumption (detection loophole), while the use of fast random basis selection and readout combined with a spatial separation of 1.3 km ensure the required locality conditions. We perform 245 trials testing the CHSH-Bell inequality $S \leq 2$ and find $S = 2.42 \pm 0.20$. A null hypothesis test yields a probability of $p = 0.039$ that a local-realist model for space-like separated sites produces data with a violation at least as large as observed, even when allowing for memory in the devices. This result rules out large classes of local realist theories, and paves the way for implementing device-independent quantum-secure communication and randomness certification.Comment: Raw data will be made available after publicatio

Detecting parent of origin and dominant QTL in a two-generation commercial poultry pedigree using variance component methodology

<p>Abstract</p> <p>Introduction</p> <p>Variance component QTL methodology was used to analyse three candidate regions on chicken chromosomes 1, 4 and 5 for dominant and parent-of-origin QTL effects. Data were available for bodyweight and conformation score measured at 40 days from a two-generation commercial broiler dam line. One hundred dams were nested in 46 sires with phenotypes and genotypes on 2708 offspring. Linear models were constructed to simultaneously estimate fixed, polygenic and QTL effects. Different genetic models were compared using likelihood ratio test statistics derived from the comparison of full with reduced or null models. Empirical thresholds were derived by permutation analysis.</p> <p>Results</p> <p>Dominant QTL were found for bodyweight on chicken chromosome 4 and for bodyweight and conformation score on chicken chromosome 5. Suggestive evidence for a maternally expressed QTL for bodyweight and conformation score was found on chromosome 1 in a region corresponding to orthologous imprinted regions in the human and mouse.</p> <p>Conclusion</p> <p>Initial results suggest that variance component analysis can be applied within commercial populations for the direct detection of segregating dominant and parent of origin effects.</p