Weather research and forecasting model simulations of extended warm-season heavy precipitation episode over the US southern great plains: Data assimilation and microphysics sensitivity experiments

This study examines eight microphysics schemes (Lin, WSM5, Eta, WSM6, Goddard, Thompson, WDM5, WDM6) in the Advanced Research Weather Research and Forecasting Model (WRF-ARW) for their reproduction of observed strong convection over the US Southern Great Plains (SGP) for three heavy precipitation events of 27-31 May 2001. It also assesses how observational analysis nudging (OBNUD), threedimensional (3DVAR) and four-dimensional variational (4DVAR) data assimilation (DA) affect simulated cloud properties relative to simulations with no DA (CNTRL). Primary evaluation data were cloud radar reflectivity measurements by the millimetre cloud radar (MMCR) at the Central Facility (CF) of the SGP site of the ARM Climate Research Facility (ACRF). All WRF-ARW microphysics simulations reproduce the intensity and vertical structure of the first two major MMCR-observed storms, although the first simulated storm initiates a few hours earlier than observed. Of three organised convective events, the model best identifies the timing and vertical structure of the second storm more than 50 hours into the simulation. For this wellsimulated cloud structure, simulated reflectivities are close to the observed counterparts in the mid- and upper troposphere, and only overestimate observed cloud radar reflectivity in the lower troposphere by less than 10 dBZ. Based on relative measures of skill, no single microphysics scheme excels in all aspects, although the WDM schemes show much-improved frequency bias scores (FBSs) in the lower troposphere for a range of reflectivity thresholds. The WDM6 scheme has improved FBSs and high simulated-observed reflectivity correlations in the lower troposphere, likely due to its large production of liquid water immediately below the melting level. Of all the DA experiments, 3DVAR has the lowest mean errors (MEs) and root mean-squared errors (RMSEs), although both the 3DVAR and 4DVAR simulations reduced noticeably the MEs for seven of eight microphysics schemes relative to CNTRL. Lower-tropospheric θe and convective available potential energy (CAPE) also are closer to the observations for the 4DVAR than CNTRL simulations. © 2013 Z. T. Segele et al

Seasonal-to-interannual variability of ethiopia/horn of Africa monsoon. Part II: Statistical multimodel ensemble rainfall predictions

© 2015 American Meteorological Society. An ensemble-based multiple linear regression technique is developed to assess the predictability of regional and national June-September (JJAS) anomalies and local monthly rainfall totals for Ethiopia. The ensemble prediction approach captures potential predictive signals in regional circulations and global sea surface temperatures (SSTs) two to three months in advance of the monsoon season. Sets of 20 potential predictors are selected from visual assessments of correlation maps that relate rainfall with regional and global predictors. Individual predictors in each set are utilized to initialize specific forward stepwise regression models to develop ensembles of equal number of statistical model estimates, which allow quantifying prediction uncertainties related to individual predictors and models. Prediction skill improvement is achieved through error minimization afforded by the ensemble. For retroactive validation (RV), the ensemble predictions reproduce well the observed all-Ethiopian JJAS rainfall variability two months in advance. The ensemble mean prediction outperforms climatology, with mean square error reduction (SSClim) of 62%. The skill of the prediction remains high for leave-one-out cross validation (LOOCV), with the observed-predicted correlation r (SSClim) being +0.81 (65%) for 1970-2002. For tercile predictions (below, near, and above normal), the ranked probability skill score is 0.45, indicating improvement compared to climatological forecasts. Similarly high prediction skill is found for local prediction of monthly rainfall total at Addis Ababa (r = +0.72) and Combolcha (r = +0.68), and for regional prediction of JJAS standardized rainfall anomalies for northeastern Ethiopia (r = +0.80). Compared to the previous generation of rainfall forecasts, the ensemble predictions developed in this paper show substantial value to benefit society

Cluster analysis of North Atlantic tropical cyclones

© 2014 Published by Elsevier B.V. Tropical cyclones (TCs) in the North Atlantic (NA) basin pose an annual risk to coastal regions, with hurricane Katrina (2005) the costliest TC in US history. This study employs K-means cluster analysis (CA) to detect the distinctive, important NA TC paths and lifecycles. Unlike previous TC cluster analyses, which examined TC tracks, the present work documents TC genesis and decay locations. Application of the silhouette coefficient provided an objective method to determine the optimal number of clusters (7 for genesis locations, 6 for preferred tracks, and 5 for decay locations). Additionally, silhouette coefficients provided the information necessary to remove storms that did not fit specific clusters, improving cluster cohesiveness. For TC genesis, K-means CA captured the separation between tropical and higher-latitude TCs. Clustering of genesis points identifies formative areas. The western NA cluster is the most active. TCs have distinct decay locations, notably in the western NA, Gulf of Mexico and western Caribbean Sea. Clustering TC tracks reveals that TCs moving to higher latitudes recurve generally, whereas Caribbean and Gulf coast TCs have straight-line tracks. Temporally, early season TC clusters form in the western Caribbean Sea, Gulf of Mexico, and western NA. Midseason TC clusters shift eastward, extending from the tropical NA to Africa. Late season TC clusters recur in the Caribbean Sea, Gulf of Mexico and western NA

Why lose weight? Reasons for seeking weight loss by overweight but otherwise healthy men

OBJECTIVE: To identify the reasons for seeking weight loss in overweight or obese but otherwise healthy men. DESIGN: Interviews, prior to intervention, with subjects who had volunteered to participate in a work-site-based weight loss study. SUBJECTS: Ninety-one overweight=obese male workers. Mean age 41, range 18 – 55 y, mean body mass index (BMI) 31.0, range 26.2 – 41.6 kg=m2. MEASUREMENTS: Anthropometric measurements; body weight and height. Body mass index calculated. A short interview using open questions to determine the individuals reason for seeking weight loss. RESULTS: The message that weight loss is beneficial to health for the overweight was recognized by all subjects regardless of BMI, and was reported as the main factor for attempting weight loss. Improved fitness and effects on appearance and well-being were reported half as often as the primary reason for weight loss. CONCLUSION: Overweight lay members of the public have accepted the health education message that weight loss can improve health. Overweight but otherwise healthy men who responded, of their own accord, to an electronic mail message offering help to lose weight did not regard obesity and overweight as primarily a cosmetic issue. This is still, however, important, especially to younger people

Inactive or moderately active human promoters are enriched for inter-individual epialleles

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Pharmacological profiling of the hemodynamic effects of cannabinoid ligands: a combined in vitro and in vivo approach

The receptors mediating the hemodynamic responses to cannabinoids are not clearly defined due to the multifarious pharmacology of many commonly used cannabinoid ligands. While both CB1 and TRPV1 receptors are implicated, G protein-coupled receptor 55 (GPR55) may also mediate some of the hemodynamic effects of several atypical cannabinoid ligands. The present studies attempted to unravel the pharmacology underlying the in vivo hemodynamic responses to ACEA (CB1 agonist), O-1602 (GPR55 agonist), AM251 (CB1 antagonist), and cannabidiol (CBD; GPR55 antagonist). Agonist and antagonist profiles of each ligand were determined by ligand-induced GTPγS binding in membrane preparations expressing rat and mouse CB1 and GPR55 receptors. Blood pressure responses to ACEA and O-1602 were recorded in anesthetized and conscious mice (wild type, CB1−/− and GPR55−/−) and rats in the absence and presence of AM251 and CBD. ACEA demonstrated GTPγS activation at both receptors, while O-1602 only activated GPR55. AM251 exhibited antagonist activity at CB1 and agonist activity at GPR55, while CBD demonstrated selective antagonist activity at GPR55. The depressor response to ACEA was blocked by AM251 and attenuated by CBD, while O-1602 did not induce a depressor response. AM251 caused a depressor response that was absent in GPR55−/− mice but enhanced by CBD, while CBD caused a small vasodepressor response that persisted in GPR55−/− mice. Our findings show that assessment of the pharmacological profile of receptor activation by cannabinoid ligands in in vitro studies alongside in vivo functional studies is essential to understand the role of cannabinoids in hemodynamic control

HLA-Driven Convergence of HIV-1 Viral Subtypes B and F Toward the Adaptation to Immune Responses in Human Populations

BACKGROUND: Cytotoxic T-Lymphocyte (CTL) response drives the evolution of HIV-1 at a host-level by selecting HLA-restricted escape mutations. Dissecting the dynamics of these escape mutations at a population-level would help to understand how HLA-mediated selection drives the evolution of HIV-1. METHODOLOGY/PRINCIPAL FINDINGS: We undertook a study of the dynamics of HIV-1 CTL-escape mutations by analyzing through statistical approaches and phylogenetic methods the viral gene gag sequenced in plasma samples collected between the years 1987 and 2006 from 302 drug-naive HIV-positive patients. By applying logistic regression models and after performing correction for multiple test, we identified 22 potential CTL-escape mutations (p-value<0.05; q-value<0.2); 10 of these associations were confirmed in samples biologically independent by a Bayesian Markov Chain Monte-Carlo method. Analyzing their prevalence back in time we found that escape mutations that are the consensus residue in samples collected after 2003 have actually significantly increased in time in one of either B or F subtype until becoming the most frequent residue, while dominating the other viral subtype. Their estimated prevalence in the viral subtype they did not dominate was lower than 30% for the majority of samples collected at the end of the 80's. In addition, when screening the entire viral region, we found that the 75% of positions significantly changing in time (p<0.05) were located within known CTL epitopes. CONCLUSIONS: Across HIV Gag protein, the rise of polymorphisms from independent origin during the last twenty years of epidemic in our setting was related to an association with an HLA allele. The fact that these mutations accumulated in one of either B or F subtypes have also dominated the other subtype shows how this selection might be causing a convergence of viral subtypes to variants which are more likely to evade the immune response of the population where they circulate

An extracellular steric seeding mechanism for Eph-ephrin signaling platform assembly

Erythropoetin-producing hepatoma (Eph) receptors are cell-surface protein tyrosine kinases mediating cell-cell communication. Upon activation, they form signaling clusters. We report crystal structures of the full ectodomain of human EphA2 (eEphA2) both alone and in complex with the receptor-binding domain of the ligand ephrinA5 (ephrinA5 RBD). Unliganded eEphA2 forms linear arrays of staggered parallel receptors involving two patches of residues conserved across A-class Ephs. eEphA2-ephrinA5 RBD forms a more elaborate assembly, whose interfaces include the same conserved regions on eEphA2, but rearranged to accommodate ephrinA5 RBD. Cell-surface expression of mutant EphA2s showed that these interfaces are critical for localization at cell-cell contacts and activation-dependent degradation. Our results suggest a 'nucleation' mechanism whereby a limited number of ligand-receptor interactions 'seed' an arrangement of receptors which can propagate into extended signaling arrays

Cognitive and affective perspective-taking in conduct-disordered children high and low on callous-unemotional traits

<p>Abstract</p> <p>Background</p> <p>Deficits in cognitive and/or affective perspective-taking have been implicated in Conduct-Disorder (CD), but empirical investigations produced equivocal results. Two factors may be implicated: (a) distinct deficits underlying the antisocial conduct of CD subgroups, (b) plausible disjunction between cognitive and affective perspective-taking with subgroups presenting either cognitive or affective-specific deficits.</p> <p>Method</p> <p>This study employed a second-order false-belief paradigm in which the cognitive perspective-taking questions tapped the character's thoughts and the affective perspective-taking questions tapped the emotions generated by these thoughts. Affective and cognitive perspective-taking was compared across three groups of children: (a) CD elevated on Callous-Unemotional traits (<it>CD-high-CU</it>, <it>n </it>= 30), (b) CD low on CU traits (<it>CD-low-CU</it>, <it>n </it>= 42), and (c) a 'typically-developing' comparison group (<it>n </it>= 50), matched in age (7.5 – 10.8), gender and socioeconomic background.</p> <p>Results</p> <p>The results revealed deficits in <it>CD-low-CU </it>children for both affective and cognitive perspective-taking. In contrast <it>CD-high-CU </it>children showed relative competency in cognitive, but deficits in affective-perspective taking, a finding that suggests an affective-specific defect and a plausible dissociation of affective and cognitive perspective-taking in <it>CD-high-CU </it>children.</p> <p>Conclusion</p> <p>Present findings indicate that deficits in cognitive perspective-taking that have long been implicated in CD appear to be characteristic of a subset of CD children. In contrast affective perspective-taking deficits characterise both CD subgroups, but these defects seem to be following diverse developmental paths that warrant further investigation.</p

Cosmogenic neutron production at the Sudbury Neutrino Observatory

Neutrons produced in nuclear interactions initiated by cosmic-ray muons present an irreducible background to many rare-event searches, even in detectors located deep underground. Models for the production of these neutrons have been tested against previous experimental data, but the extrapolation to deeper sites is not well understood. Here we report results from an analysis of cosmogenically produced neutrons at the Sudbury Neutrino Observatory. A specific set of observables are presented, which can be used to benchmark the validity of geant4 physics models. In addition, the cosmogenic neutron yield, in units of 10-4 cm2/(g·μ), is measured to be 7.28±0.09(stat)-1.12+1.59(syst) in pure heavy water and 7.30±0.07(stat)-1.02+1.40(syst) in NaCl-loaded heavy water. These results provide unique insights into this potential background source for experiments at SNOLAB