Short-scale turbulent fluctuations driven by the electron-temperature gradient in the national spherical torus experiment

Measurements with coherent scattering of electromagnetic waves in plasmas of the National Spherical Torus Experiment indicate the existence of turbulent fluctuations in the range of wave numbers k(perpendicular to)rho(e)=0.1-0.4, corresponding to a turbulence scale length nearly equal to the collisionless skin depth. Experimental observations and agreement with numerical results from a linear gyrokinetic stability code support the conjecture that the observed turbulence is driven by the electron-temperature gradient.X1155sciescopu

Free randomness can be amplified

Are there fundamentally random processes in nature? Theoretical predictions, confirmed experimentally, such as the violation of Bell inequalities, point to an affirmative answer. However, these results are based on the assumption that measurement settings can be chosen freely at random, so assume the existence of perfectly free random processes from the outset. Here we consider a scenario in which this assumption is weakened and show that partially free random bits can be amplified to make arbitrarily free ones. More precisely, given a source of random bits whose correlation with other variables is below a certain threshold, we propose a procedure for generating fresh random bits that are virtually uncorrelated with all other variables. We also conjecture that such procedures exist for any non-trivial threshold. Our result is based solely on the no-signalling principle, which is necessary for the existence of free randomness.Comment: 5+7 pages, 2 figures. Updated to match published versio

Sex-specific associations of adiposity with cardiometabolic traits in the UK: A multi-life stage cohort study with repeat metabolomics

Background Sex differences in cardiometabolic disease risk are commonly observed across the life course but are poorly understood and may be due to different associations of adiposity with cardiometabolic risk in females and males. We examined whether adiposity is differently associated with cardiometabolic trait levels in females and males at 3 different life stages. Methods and findings Data were from 2 generations (offspring, Generation 1 [G1] born in 1991/1992 and their parents, Generation 0 [G0]) of a United Kingdom population-based birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC). Follow-up continues on the cohort; data up to 25 y after recruitment to the study are included in this analysis. Body mass index (BMI) and total fat mass from dual-energy X-ray absorptiometry (DXA) were measured at mean age 9 y, 15 y, and 18 y in G1. Waist circumference was measured at 9 y and 15 y in G1. Concentrations of 148 cardiometabolic traits quantified using nuclear magnetic resonance spectroscopy were measured at 15 y, 18 y, and 25 y in G1. In G0, all 3 adiposity measures and the same 148 traits were available at 50 y. Using linear regression models, sex-specific associations of adiposity measures at each time point (9 y, 15 y, and 18 y) with cardiometabolic traits 3 to 6 y later were examined in G1. In G0, sex-specific associations of adiposity measures and cardiometabolic traits were examined cross-sectionally at 50 y. A total of 3,081 G1 and 4,887 G0 participants contributed to analyses. BMI was more strongly associated with key atherogenic traits in males compared with females at younger ages (15 y to 25 y), and associations were more similar between the sexes or stronger in females at 50 y, particularly for apolipoprotein B-containing lipoprotein particles and lipid concentrations. For example, a 1 standard deviation (SD) (3.8 kg/m2) higher BMI at 18 y was associated with 0.36 SD (95% confidence interval [CI] = 0.20, 0.52) higher concentrations of extremely large very-low-density lipoprotein (VLDL) particles at 25 y in males compared with 0.15 SD (95% CI = 0.09, 0.21) in females, P value for sex difference = 0.02. By contrast, at 50 y, a 1 SD (4.8 kg/m2) higher BMI was associated with 0.33 SD (95% CI = 0.25, 0.42) and 0.30 SD (95% CI = 0.26, 0.33) higher concentrations of extremely large VLDL particles in males and females, respectively, P value for sex difference = 0.42. Sex-specific associations of DXA-measured fat mass and waist circumference with cardiometabolic traits were similar to findings for BMI and cardiometabolic traits at each age. The main limitation of this work is its observational nature, and replication in independent cohorts using methods that can infer causality is required. Conclusions The results of this study suggest that associations of adiposity with adverse cardiometabolic risk begin earlier in the life course among males compared with females and are stronger until midlife, particularly for key atherogenic lipids. Adolescent and young adult males may therefore be high priority targets for obesity prevention efforts

Genetic mapping and developmental timing of transmission ratio distortion in a mouse interspecific backcross

<p>Abstract</p> <p>Background</p> <p>Transmission ratio distortion (TRD), defined as statistically significant deviation from expected 1:1 Mendelian ratios of allele inheritance, results in a reduction of the expected progeny of a given genotype. Since TRD is a common occurrence within interspecific crosses, a mouse interspecific backcross was used to genetically map regions showing TRD, and a developmental analysis was performed to identify the timing of allele loss.</p> <p>Results</p> <p>Three independent events of statistically significant deviation from the expected 50:50 Mendelian inheritance ratios were observed in an interspecific backcross between the <it>Mus musculus </it>A/J and the <it>Mus spretus </it>SPRET/EiJ inbred strains. At weaning <it>M. musculus </it>alleles are preferentially inherited on Chromosome (Chr) 7, while <it>M. spretus </it>alleles are preferentially inherited on Chrs 10 and 11. Furthermore, alleles on Chr 3 modify the TRD on Chr 11. All TRD loci detected at weaning were present in Mendelian ratios at mid-gestation and at birth.</p> <p>Conclusions</p> <p>Given that Mendelian ratios of inheritance are observed for Chr 7, 10 and 11 during development and at birth, the underlying causes for the interspecific TRD events are the differential post-natal survival of pups with specific genotypes. These results are consistent with the TRD mechanism being deviation from Mendelian inheritance rather than meiotic drive or segregation distortion.</p

Enterprise social network success: Evidences from a multinational corporation

In a globalized world, where companies operate across different locations and work becomes increasingly complex, collaboration in a diversity of ways is required among employees to perform tasks more effectively. Following a case study methodology that involved six interviews across three different country locations, this research addresses the phenomenon of Enterprise Social Networks (ESN) in a multinational corporation with a focus on the assessment of ESN success. The findings show that the company, while trying to assess the success of Yammer, the freemium social networking service at use, has mainly relied on analytics tools to measure usage through indicators such as the total number of users. However, the extent to which ESN is used does not provide a complete picture of ESN success. Business value from that ESN usage is another dimension to be considered to assess success. Therefore, the study of specific ESN usage scenarios that are perceived to have a trackable impact on business results can be used to assess ESN business value on top of ESN usage to fully understand ESN success.COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013info:eu-repo/semantics/publishedVersio

Trends in UK cancer trials: results from the UK Coordinating Committee for Cancer Research National Register of Cancer Trials

We aimed to study trends in the design and conduct of randomised controlled trials (RCTs) in cancer in the UK, using the UK Coordinating Committee for Cancer Research (UKCCCR) National Register of Cancer Trials (NRCT). We conducted a descriptive survey of 520 UK RCTs in cancer that were registered on the UKCCCR NRCT. All trials had been initiated between 1971 and 2000. Trials on the NRCT have been conducted in a wide variety of cancer types, but with a third in breast (22%) or lung cancer (11%). They have largely been funded by the UK public and charity sectors. Overall, there has been a sustained rise in the total numbers of patients entering UK cancer trials over time with a trend towards larger, multicentre trials, greater recruitment targets and a marked reduction in the average time taken to complete trials. Trends in the design and conduct of noncommercial cancer RCTs from 1971 to 2000 are encouraging. It will be interesting to see how they develop in light of the implementation of recent national initiatives regarding cancer clinical trials in the UK

Conclusive quantum steering with superconducting transition edge sensors

Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavourable events in losses. Here we close this "detection loophole" by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented ~62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.Comment: Preprint of 7 pages, 3 figures; the definitive version is published in Nature Communications, see below. Also, see related experimental work by A. J. Bennet et al., arXiv:1111.0739 and B. Wittmann et al., arXiv:1111.076

Guidance for the design and reporting of studies evaluating the clinical performance of tests for present or past SARS-CoV-2 infection

Testing for SARS-CoV-2 infection is key in managing the current pandemic. More than 1700 preprints and peer reviewed journal articles evaluating tests for SARS-CoV-2 infection have been published as of January 2021. However, evaluations of these studies have identified many methodological issues, leading to a high risk of bias and difficulties applying the results in practice. Better guidance is urgently needed on the conduct and interpretation of these studies. This article outlines the principles for defining the intended purpose of the test; study population selection; reference standard, test timing; and other critical considerations for the design, reporting, and interpretation of diagnostic accuracy studies. The implementation and accuracy of SARS-CoV-2 tests have major implications for individuals and communities, balancing the potential consequences of continued infection against the need for public health measures, such as the restriction of movements and social activities. Decision making in the current pandemic requires a clear understanding of the clinical performance and limitations of testing. This article provides guidance to assist researchers design robust diagnostic accuracy studies, assist publishers and peer reviewers to assess such studies, and support clinicians and policy makers in their evaluation of the evidence on SARS-CoV-2 testing for clinical and public health decisions. The guidance aims to ensure that studies evaluating the diagnostic accuracy of SARS-CoV-2 tests are conducted as rigorously as possible, in an efficient and timely way

Yours ever (well, maybe): Studies and signposts in letter writing

Electronic mail and other digital communications technologies seemingly threaten to end the era of handwritten and typed letters, now affectionately seen as part of snail mail. In this essay, I analyze a group of popular and scholarly studies about letter writing-including examples of pundits critiquing the use of e-mail, etiquette manuals advising why the handwritten letter still possesses value, historians and literary scholars studying the role of letters in the past and what it tells us about our present attitudes about digital communications technologies, and futurists predicting how we will function as personal archivists maintaining every document including e-mail. These are useful guideposts for archivists, providing both a sense of the present and the past in the role, value and nature of letters and their successors. They also provide insights into how such documents should be studied, expanding our gaze beyond the particular letters, to the tools used to create them and the traditions dictating their form and function. We also can discern a role for archivists, both for contributing to the literature about documents and in using these studies and commentaries, suggesting not a new disciplinary realm but opportunities for new interdisciplinary work. Examining a documentary form makes us more sensitive to both the innovations and traditions as it shifts from the analog to the digital; we can learn not to be caught up in hysteria or nostalgia about one form over another and archivists can learn about what they might expect in their labors to document society and its institutions. At one time, paper was part of an innovative technology, with roles very similar to the Internet and e-mail today. It may be that the shifts are far less revolutionary than is often assumed. Reading such works also suggests, finally, that archivists ought to rethink how they view their own knowledge and how it is constructed and used. © 2010 Springer Science+Business Media B.V