bluuebunny/crossref_metadata_2025_split huggingface dataset:
Connecting substellar and stellar formation: the role of the host star’s metallicity
Authors: Maldonado J. , Villaver E. , Eiroa C. , Micela G. 
Published: March 2019

Context.Most of our current understanding of the planet formation mechanism is based on the planet metallicity correlation derived mostly from solar-type stars harbouring gas-giant planets.Aims.To achieve a more extensive grasp on the substellar formation process, we aim to analyse in terms of their metallicity a diverse sample of stars (in terms of mass and spectral type) covering the whole range of possible outcomes of the planet formation process (from planetesimals to brown dwarfs and low-mass binaries).Methods.Our methodology is based on the use of high-precision stellar parameters derived by our own group in previous works from high-resolution spectra by using the iron ionisation and equilibrium conditions. All values were derived in an homogeneous way, except for the M dwarfs where a methodology based on the use of pseudo equivalent widths of spectral features was used.Results.Our results show that as the mass of the substellar companion increases the metallicity of the host star tends to lower values. The same trend is maintained when analysing stars with low-mass stellar companions and a tendency towards a wide range of host star’s metallicity is found for systems with low-mass planets. We also confirm that more massive planets tend to orbit around more massive stars.Conclusions.The core-accretion formation mechanism for planet formation achieves its maximum efficiency for planets with masses in the range 0.2–2MJup. Substellar objects with higher masses have higher probabilities of being formed as stars. Low-mass planets and planetesimals might be formed by core-accretion even around low-metallicity stars.
Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE-Constellation
Authors: Kallinger T. , Beck P. G. , Hekker S. , Huber D. , Kuschnig R. , Rockenbauer M. , Winter P. M. , Weiss W. W. , Handler G. , Moffat A. F. J. , Pigulski A. , Popowicz A. , Wade G. A. , Zwintz K. 
Published: March 2019

Context. The study of stellar structure and evolution depends crucially on accurate stellar parameters. The photometry from space telescopes has provided superb data that enabled the asteroseismic characterisation of thousands of stars. However, typical targets of space telescopes are rather faint and complementary measurements are difficult to obtain. On the other hand, the brightest, otherwise well-studied stars, are lacking seismic characterization.
Aims. Our goal is to use the granulation and/or oscillation timescales measured from photometric time series of bright red giants (1.6 ≤ V mag ≤ 5.3) observed with BRITE-Constellation to determine stellar surface gravities and masses.
Methods. We used probabilistic methods to characterise the granulation and/or oscillation signal in the power density spectra and the autocorrelation function of the BRITE-Constellation time series.
Results. We detect a clear granulation and/or oscillation signal in 23 red giant stars and extract the corresponding timescales from the power density spectra as well as the autocorrelation function of the BRITE-Constellation time series. To account for the recently discovered non-linearity of the classical seismic scaling relations, we used parameters from a large sample of Kepler stars to re-calibrate the scalings of the high- and low-frequency components of the granulation signal. We developed a method to identify which component is measured if only one granulation component is statistically significant in the data. We then used the new scalings to determine the surface gravity of our sample stars, finding them to be consistent with those determined from the autocorrelation signal of the time series. We further used radius estimates from the literature to determine the stellar masses of our sample stars from the measured surface gravities. We also defined a statistical measure for the evolutionary stage of the stars.
Conclusions. Our sample of stars covers low-mass stars on the lower giant branch to evolved massive supergiants and even though we cannot verify our mass estimates with independent measurements from the literature, they appear to be at least good enough to separate high-mass from low-mass stars. Given the large known but usually not considered systematic uncertainties in the previous model-based mass estimates, we prefer our model-independent measurements.
Effects of Melatonin Supplementation On Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Authors: Hadi Amir , Ghaedi Ehsan , Moradi Sajjad , Pourmasoumi Makan , Ghavami Abed , Kafeshani Marzieh 
Published: March 2019

AbstractMelatonin is a physiological indoleamine secreted from the pineal gland into the bloodstream. This hormone has antioxidant effects in cardiovascular disease, but the evidence regarding its effects on blood pressure (BP) has not been conclusive. Therefore, we assessed the impact of melatonin supplementation on systolic BP (SBP) and diastolic BP (DBP) through a systematic review and meta—analysis of available randomized controlled trials (RCTs). Medline, Scopus, Web of Science, Cochrane library, and Google scholar (until May 2018) were searched to identify potential RCTs with information on melatonin supplementation and BP. Mean Differences (MD) were pooled using a random-effects model. Standard methods were used for assessment of heterogeneity, sensitivity analysis, and publication bias. Pooling 5 RCTs (6 treatment arms) together identified significant reduction for SBP (MD: −3.43 mmHg, 95% confidence interval (CI): −5.76 to −1.09, p=0.004) and DBP (MD: −3.33 mmHg, 95% CI: −4.57 to −2.08, p<0.001) after supplementation with melatonin compared with control treatment. The sensitivity analysis indicated that the results were robust. We did not observe any evidence regarding publication bias. The findings of this meta-analysis support the overall favorable effect of melatonin supplementation on BP regulation.
Report of a Novel Homozygous Nonsense DDR2 Mutation in an Indian Adult Male with Spondylo-meta-epiphyseal Dysplasia, Short Limb-Abnormal Calcification Type
Authors: Gupta Neerja , Correa Alec Reginald Errol , Jana Manisha , Kabra Madhulika 
Published: March 2019

AbstractSpondylo-meta-epiphyseal dysplasia, short limb-abnormal calcification type is a rare autosomal recessive disorder causing severe disproportionate short stature along with typical radiological features. We report an adult male patient with typical features and a novel homozygous nonsense mutation c.2422C > T (p.Gln808Ter) in DDR2. This is the first report of the disease from India.
Systematic analysis of agreement between metrics and peer review in the UK REF
Authors: Traag V. A. , Waltman L. 
Published: March 2019

AbstractWhen performing a national research assessment, some countries rely on citation metrics whereas others, such as the UK, primarily use peer review. In the influential Metric Tide report, a low agreement between metrics and peer review in the UK Research Excellence Framework (REF) was found. However, earlier studies observed much higher agreement between metrics and peer review in the REF and argued in favour of using metrics. This shows that there is considerable ambiguity in the discussion on agreement between metrics and peer review. We provide clarity in this discussion by considering four important points: (1) the level of aggregation of the analysis; (2) the use of either a size-dependent or a size-independent perspective; (3) the suitability of different measures of agreement; and (4) the uncertainty in peer review. In the context of the REF, we argue that agreement between metrics and peer review should be assessed at the institutional level rather than at the publication level. Both a size-dependent and a size-independent perspective are relevant in the REF. The interpretation of correlations may be problematic and as an alternative we therefore use measures of agreement that are based on the absolute or relative differences between metrics and peer review. To get an idea of the uncertainty in peer review, we rely on a model to bootstrap peer review outcomes. We conclude that particularly in Physics, Clinical Medicine, and Public Health, metrics agree relatively well with peer review and may offer an alternative to peer review.
Bureaucratic reform and Russian transition: the puzzles of policy-making process
Authors: Inkina Svetlana 
Published: March 2019

AbstractDuring the two decades of post-Soviet transition, Russia has created a complex system of civil service and public administration. This system was first reformed in the early 1990s and then again in the early 2000s. The analysis presented here fills a gap in the existing literature concerning the dynamic of change associated with Russian civil service reform (CSR). It is argued that the process of bureaucratic modernization in Russia is undermined by the ambivalent nature of policy leadership with its financial, administrative, and technical support, and the ongoing bargain among policy advocates and policy implementers. In order to account for the outcomes reached by policy-makers, the paper presents a detailed analysis of expert interviews collected by the author among research community specialists, federal legislators, and other participants in the reform. The discussion highlights the importance of power dynamics, which resolves conflicting views of CSR among policy formulators and policy implementers. The findings, which consist of identifying necessary and sufficient conditions of the change process, have implications for studies of modern Russian politics, states in regime transition, and world-wide modernization.
Positronium emission from MgO smoke nanocrystals
Authors: Gurung L , Alonso A M , Babij T J , Cooper B S , Shluger A L , Cassidy D B 
Published: March 2019

Abstract
We report experiments in which positronium (Ps) atoms were created in a thick layer of MgO smoke powder deposited on a thin silicon nitride substrate. The experimental arrangement was such that a positron beam could be implanted directly into the top of the MgO layer or be transmitted through the substrate, allowing Ps to be produced within ≈100 nm or 30 μm of the powder-vacuum interface. The transverse kinetic energy of Ps atoms emitted into vacuum was measured via the Doppler broadening of 13S

1

→

2

3

P
J
transitions, and found to be E
x ≈ 350 meV, regardless of how far Ps atoms had traveled through the powder layer. Our data are not consistent with the model in which energetic Ps atoms emitted into the internal free volume of a porous material are cooled via multiple surface collisions, and instead indicate that in nanocrystals lower energy Ps is generated, with negligible subsequent cooling in the large open volumes of the powder. Our experiments also demonstrate that SiN substrates coated with MgO smoke can provide a simple and inexpensive method for producing Ps transmission targets.
Probabilistic count matrix factorization for single cell expression data analysis
Authors: Durif Ghislain , Modolo Laurent , Mold Jeff E , Lambert-Lacroix Sophie , Picard Franck 
Published: March 2019

Abstract

Motivation
The development of high-throughput single-cell sequencing technologies now allows the investigation of the population diversity of cellular transcriptomes. The expression dynamics (gene-to-gene variability) can be quantified more accurately, thanks to the measurement of lowly expressed genes. In addition, the cell-to-cell variability is high, with a low proportion of cells expressing the same genes at the same time/level. Those emerging patterns appear to be very challenging from the statistical point of view, especially to represent a summarized view of single-cell expression data. Principal component analysis (PCA) is a most powerful tool for high dimensional data representation, by searching for latent directions catching the most variability in the data. Unfortunately, classical PCA is based on Euclidean distance and projections that poorly work in presence of over-dispersed count data with dropout events like single-cell expression data.

Results
We propose a probabilistic Count Matrix Factorization (pCMF) approach for single-cell expression data analysis that relies on a sparse Gamma-Poisson factor model. This hierarchical model is inferred using a variational EM algorithm. It is able to jointly build a low dimensional representation of cells and genes. We show how this probabilistic framework induces a geometry that is suitable for single-cell data visualization, and produces a compression of the data that is very powerful for clustering purposes. Our method is competed against other standard representation methods like t-SNE, and we illustrate its performance for the representation of single-cell expression data.

Availability and implementation
Our work is implemented in the pCMF R-package (https://github.com/gdurif/pCMF).

Supplementary information
Supplementary data are available at Bioinformatics online.
Lessons of an Honour Code: A Consideration of Conflict-related Processes and Interpersonal Violence
Authors: Berg Mark T , Rogers Ethan M , Taylor Bruce G , Liu Weiwei , Mumford Elizabeth A 
Published: March 2019

Abstract
Criminological research has long suggested that attitudes concerned with honour and aggression, such as the ‘street code’, are related to violent offending and victimization. Comparatively, little information is known, however, about the mechanisms through which these attitudes increase violence. Drawing from interactionist perspectives of aggression and subcultural theories, we examine the mediating role of two conflict-related tendencies: disputatiousness and remedial actions. We also examine the extent to which remedial actions moderate the association between disputatiousness and violence. Predictions are tested using longitudinal data from a nationally representative sample of young adults in the United States. Results show that conflict-related tendencies mediate the pathways linking the street code to violent offending and victimization. In addition, remedial actions temper the association between disputatiousness and violence involvement.
Mapping Criminological Engagements Within Radicalization Studies
Authors: Ahmad Fahad , Monaghan Jeffrey 
Published: March 2019

AbstractRadicalization theories positing a process towards violence are de rigueur in policy circles yet solicit mixed reactions within the academy. Attempting to build a more robust theory of radicalization, scholars have turned towards criminology. On the basis of a survey of literature where radicalization engages criminology, this article maps theories taken up to advance knowledge of radicalization as a process towards terrorist violence. The mapping exercise demonstrates a growing spectrum of criminological theories referenced by radicalization studies; however, these engagements have been selective: tending towards individualistic theories with limited (but recent) engagements with constructivist and structural theory. Contributing to critical interventions within the accelerating domains of theorizing radicalization to violence, we conclude that these engagements lack some of criminology’s broader reflexivity about its object of study.
Telomere length, arsenic exposure and risk of basal cell carcinoma of skin
Authors: Srinivas Nalini , Rachakonda Sivaramakrishna , Hielscher Thomas , Calderazzo Silvia , Rudnai Peter , Gurzau Eugen , Koppova Kvetoslava , Fletcher Tony , Kumar Rajiv 
Published: March 2019

Abstract
Telomere length per se a heritable trait has been reported to be associated with different diseases including cancers. In this study, based on arsenic-exposed 528 cases with basal cell carcinoma (BCC) of skin and 533 healthy controls, we investigated effect of telomere length, measured by real-time PCR, on the disease risk. We observed a statistically significant association between decreased telomere length and increased BCC risk [odds ratio (OR) = 5.92, 95% confidence interval (CI) = 3.92 to 9.01, P < 0.0001]. Due to confounder effect of arsenic exposure, in a two-sample Mendelian randomization (MR), telomere length associated single-nucleotide polymorphisms as instrument variables violated valid assumptions; however, one-sample MR adjusted for arsenic exposure indicated an increased risk of BCC with short telomeres. The interaction between arsenic exposure and telomere length on BCC risk was statistically significant (P = 0.02). Within each tertile based on arsenic exposure, the individuals with shorter telomeres were at an increased risk of BCC, with highest risk being in the highest exposed group (OR = 16.13, 95% CI = 6.71 to 40.00, P < 0.0001), followed by those in medium exposure group and low exposure group. The combined effect of highest arsenic exposure and shortest telomeres on BCC risk (OR = 10.56, 95% CI = 5.14 to 21.70) showed a statistically significant departure from additivity (interaction contrast ratio 6.56, P = 0.03). Our results show that in the presence of arsenic exposure, decreased telomere length predisposes individuals to increased risk of BCC, with the effect being synergistic in individuals with highest arsenic exposure and shortest telomeres.
Dysregulated Prefrontal Cortical RhoA Signal Transduction in Bipolar Disorder with Psychosis: New Implications for Disease Pathophysiology
Authors: Kermath Bailey A , Vanderplow Amanda M , Cahill Michael E 
Published: March 2019

Abstract
While research has identified alterations in dorsolateral prefrontal cortical function as a key factor to the etiology of bipolar disorder, few studies have uncovered robust changes in protein signal transduction pathways in this disorder. Given the direct relevance of protein-based expressional alterations to cellular functions and because many of the key regulatory mechanisms for the disease pathogenesis likely include alterations in protein activity rather than changes in expression alone, the identification of alterations in discrete signal transduction pathways in bipolar disorder would have broad implications for understanding the disease pathophysiology. As prior microarray data point to a previously unrecognized involvement of the RhoA network in bipolar disorder, here we investigate the protein expression and activity of key components of a RhoA signal transduction pathway in dorsolateral prefrontal cortical homogenates from subjects with bipolar disorder. The results of this investigation implicate overactivation of prefrontal cortical RhoA signaling in specific subtypes of bipolar disorder. The specificity of these findings is demonstrated by a lack of comparable changes in schizophrenia; however, our findings do identify convergence between both disorders at the level of activity-mediated actin cytoskeletal regulation. These findings have implications for understanding the altered cortical synaptic connectivity of bipolar disorder.
A Jackknife Estimator of Variance for a Random Tessellated Stratified Sampling Design
Authors: Magnussen Steen , Nord-Larsen Thomas 
Published: March 2019

AbstractSemisystematic sampling designs—in which a population area frame is tessellated into cells, and a randomly located sample is taken from each cell—affords random tessellated stratified (RTS) Horvitz–Thompson-type estimators. Forest inventory applications with RTS estimators are rare, possibly because of computational complexities with the estimation of variance. To reduce this challenge, we propose a jackknife estimator of variance for RTS designs. We demonstrate an application with a model-assisted ratio of totals estimator and data from the Danish National Forest Inventory. RTS estimators of standard error were, as a rule, smaller than comparable estimates obtained under the assumption of simple random sampling. The proposed jackknife estimator performed well.
‘Gender is not even a side issue…it’s a non-issue’: career trajectories and experiences from the perspective of male and female healthcare managers in Kenya
Authors: Muraya Kelly W , Govender Veloshnee , Mbachu Chinyere , Uguru Nkoli P , Molyneux Sassy 
Published: March 2019

AbstractWomen comprise a significant proportion of the health workforce globally but remain under-represented in the higher professional categories. Concern about the under-representation of women in health leadership positions has resulted in increased research on the topic, although this research has focused primarily on high-income countries. An improved understanding of the career trajectories and experiences of healthcare leaders in low- and middle-income countries (LMICs), and the role of gender, is therefore needed. This qualitative case study was undertaken in two counties in coastal Kenya. Drawing on the life-history approach, 12 male and 13 female healthcare leaders were interviewed between August 2015 and July 2016 on their career progression and related experiences. Although gender was not spontaneously identified as a significant influence, closer exploration of responses revealed that gendered factors played an important role. Most fundamentally, women’s role as child bearers and gendered societal expectations including child nurturing and other domestic responsibilities can influence their ability to take up leadership opportunities, and their selection and appointment as leaders. Women’s selection and appointment as leaders may also be influenced by positive discrimination policies (in favour of women), and by perceptions of women and men as having different leadership styles (against women, who some described as more emotive and reactive). These gendered influences intersect in relatively invisible ways with other factors more readily identified by respondents to influence their progression and experience. These factors included: professional cadre, with doctors more likely to be selected into leadership roles; and personal and professional support systems ranging from family support and role models, through to professional mentorship and continuing education. We discuss the implications of these findings for policy, practice and research, including highlighting the need for more in-depth intersectionality analyses of leadership experience in LMICs.
Beyond positive a priori bias: reframing community engagement in LMICs
Authors: Abimbola Seye 
Published: March 2019

AbstractShowing the causal link between community engagement and improved health outcomes is a ‘holy grail’ of health policy. This article argues that this ‘holy grail’ has remained elusive because community engagement in primary health care is under-theorized, having been based on positive a priori assumptions, e.g. that people necessarily want to be engaged in governing their health system. By adopting a theory-driven approach and an agnostic premise, we show that understanding why, how and when community engagement may emerge or function spontaneously is important for informing efforts to support community engagement in primary health care primary health care governance. We draw on empirical research on community engagement in Nigeria and on the literature to identify the ‘why’ (coalition of service users can emerge in response to under-governance); the ‘how’ (five modes: through meetings; reaching out within their community; lobbying governments; augmenting government support; and taking control of service delivery) and the ‘when’ (as geographical, socio-economic and institutional context align, such that the benefits of action outweigh costs). Understanding the broad patterns of mechanisms and of contextual factors that apply across communities is, after all, our ‘holy grail’—and this understanding should inform efforts to tailor support for community engagement in governance in different settings.