571 research outputs found
Ab Initio Evidence for the Formation of Impurity d(3z^2-r^2) Holes in Doped La_{2-x}Sr_xCuO_4
Using the spin unrestricted Becke-3-Lee-Yang-Parr density functional, we
computed the electronic structure of explicitly doped La_{2-x}Sr_xCuO_4 (x =
0.125, 0.25, and 0.5). At each doping level, an impurity hole band is formed
within the undoped insulating gap. This band is well-localized to CuO_6
octahedra adjacent to the Sr impurities. The nature of the impurity hole is
A_{1g} in symmetry, formed primarily from the z^2 orbital on the Cu and p_z
orbitals on the apical O's. There is a strong triplet coupling of this hole
with the intrinsic B_{1g} Cu x^2-y^2/O1 p_{sigma} hole on the same site.
Optimization of the c coordinate of the apical O's in the doped CuO_6
octahedron lead to an asymmetric anti-Jahn-Teller distortion of the O2 atoms
toward the central Cu. In particular, the O2 atom between the Cu and Sr is
displaced 0.26 A while the O2 atom between the Cu and La is displaced 0.10 A.
Contrary to expectations, investigation of a 0.1 A enhanced Jahn-Teller
distortion of this octahedron does not force formation of an x^2-y^2 hole, but
instead leads to migration of the z^2 hole to the four other CuO_6 octahedra
surrounding the Sr impurity. This latter observation offers a simple
explanation for the bifurcation of the Sr-O2 distance revealed in x-ray
absorption fine structure data.Comment: Submitted to Phys. Rev. B. See http://www.firstprinciples.com for
more informatio
Angular momenta creation in relativistic electron-positron plasma
Creation of angular momentum in a relativistic electron-positron plasma is
explored. It is shown that a chain of angular momentum carrying vortices is a
robust asymptotic state sustained by the generalized nonlinear Schrodinger
equation characteristic to the system. The results may suggest a possible
electromagnetic origin of angular momenta when it is applied to the MeV epoch
of the early Universe.Comment: 20 pages, 6 figure
Low protein intake during the preconception period in beef heifers affects offspring and maternal behaviour
Maternal low protein diets prior to conception alter embryo and fetal development and are associated with detrimental outcomes in the offspring in many species. The aim of this study in beef cattle was to investigate the effect of preconception dietary protein upon maternal and offspring behaviour at birth concomitant with the associated hormonal profile. Sixty days prior to conception, nulliparous yearling heifers (n = 85) were fed either a High (PreH: 18%; n = 43) or Low (PreL: 10%; n = 42) crude protein diet, followed by a control diet throughout gestation. After calving, each cow-calf pair was penned individually, accelerometers fitted, and each pen observed continuously via video recordings. Cows fed on the low protein diet during preconception showed an increase in standing time (P [less than] 0.01); while calves born to heifers receiving the PreL diet showed an increase in suckling time (P = 0.04). These calves were also heavier at birth than calves from PreH mothers (P [less than] 0.01). In conclusion, low maternal dietary protein prior to conception in beef heifers modifies both offspring feeding behaviour and birth weight, and cow’s standing times
Wesson's IMT with a Weylian bulk
The foundations of Wesson's induced matter theory are analyzed. It is shown
that the 5D empty bulk must be regarded rather as a Weylian space than as a
Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is
elaborated and discussed. The bulk possesses in addition to the metric tensor a
Weylian connection vector as well Dirac's gauge function; there are no sources
(mass, current) in the bulk. On the 4D brane one obtains a geometrically based
unified theory of gravitation and electromagnetism with mass, currents and
equations induced by the 5D bulkComment: 29 page
Bovine sperm defects are affected by breed, age, season and region
This study reports the distribution of sperm morphology defects by breed, age, season and region of 11,387 bulls in 500 herds in Australia and near Pacific Islands during annual BBSE. Bull location was divided into 4 broad climatic regions based upon temperature, vegetation and climatic risk. Taking into account the impact of age, season, region, and breed there were differences between breeds in both percent morphologically normal sperm and in some individual categories of sperm abnormality (P < 0.001). Independent of breed, season and region, proximal droplets were significantly increased in bulls less than 20 months of age. This is the first study to comprehensively collect data from this wide geographical area and compare sperm morphology profiles among the Bos indicus and Bos taurus breeds. The findings of this study will act as a guide for veterinary practitioners and cattle breeders in the proportion of bulls that can be expected to pass the PNS test, by breed, age and region, based on a robust data set
Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits
Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)
Genome-wide association study identifies 30 Loci Associated with Bipolar Disorder
This paper is dedicated to the memory of Psychiatric Genomics Consortium (PGC) founding member and Bipolar disorder working group co-chair Pamela Sklar. We thank the participants who donated their time, experiences and DNA to this research, and to the clinical and scientific teams that worked with them. We are deeply indebted to the investigators who comprise the PGC. The views expressed are those of the authors and not necessarily those of any funding or regulatory body. Analyses were carried out on the NL Genetic Cluster Computer (http://www.geneticcluster.org ) hosted by SURFsara, and the Mount Sinai high performance computing cluster (http://hpc.mssm.edu).Bipolar disorder is a highly heritable psychiatric disorder. We performed a genome-wide association study including 20,352 cases and 31,358 controls of European descent, with follow-up analysis of 822 variants with P<1x10-4 in an additional 9,412 cases and 137,760 controls. Eight of the 19 variants that were genome-wide significant (GWS, p < 5x10-8) in the discovery GWAS were not GWS in the combined analysis, consistent with small effect sizes and limited power but also with genetic heterogeneity. In the combined analysis 30 loci were GWS including 20 novel loci. The significant loci contain genes encoding ion channels, neurotransmitter transporters and synaptic components. Pathway analysis revealed nine significantly enriched gene-sets including regulation of insulin secretion and endocannabinoid signaling. BDI is strongly genetically correlated with schizophrenia, driven by psychosis, whereas BDII is more strongly correlated with major depressive disorder. These findings address key clinical questions and provide potential new biological mechanisms for BD.This work was funded in part by the Brain and Behavior Research Foundation, Stanley Medical Research Institute, University of Michigan, Pritzker Neuropsychiatric Disorders Research Fund L.L.C., Marriot Foundation and the Mayo Clinic Center for Individualized Medicine, the NIMH Intramural Research Program; Canadian Institutes of Health Research; the UK Maudsley NHS Foundation Trust, NIHR, NRS, MRC, Wellcome Trust; European Research Council; German Ministry for Education and Research, German Research Foundation IZKF of Münster, Deutsche Forschungsgemeinschaft, ImmunoSensation, the Dr. Lisa-Oehler Foundation, University of Bonn; the Swiss National Science Foundation; French Foundation FondaMental and ANR; Spanish Ministerio de Economía, CIBERSAM, Industria y Competitividad, European Regional Development Fund (ERDF), Generalitat de Catalunya, EU Horizon 2020 Research and Innovation Programme; BBMRI-NL; South-East Norway Regional Health Authority and Mrs. Throne-Holst; Swedish Research Council, Stockholm County Council, Söderström Foundation; Lundbeck Foundation, Aarhus University; Australia NHMRC, NSW Ministry of Health, Janette M O'Neil and Betty C Lynch
Formulation design and evaluation of Cefuroxime axetil 125 mg immediate release tablets using different concentration of sodium lauryl sulphate as solubility enhancer
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015
Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context.
Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI).
Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa.
Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden.
Funding: Bill & Melinda Gates Foundation
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