Protons as the prime contributors to the storm time ring current

Following a large magnetic storm (17 June 1972), Explorer 45 measured the equatorial particle populations and magnetic field. Using data obtained during the symmetic recovery phase, it is shown that through a series of self-consistent calculations, the measured protons with energies from 1 to 872 keV, can account for the observed ring current magnetic effects within experimental uncertainities. This enables an upper limit to be set for the heavy ion contribution to the storm time ring current

Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation

Measurements of the two dimensional angular correlation of the electron-positron annihilation radiation have been done in the past to detect the momentum spin density and the Fermi surface. We point out that the momentum spin density and the Fermi Surface of ferromagnetic metals can be revealed within great detail owing to the large cancellation of the electron-positron matrix elements which in paramagnetic multiatomic systems plague the interpretation of the experiments. We prove our conjecture by calculating the momentum spin density and the Fermi surface of the half metal CrO2, who has received large attention due to its possible applications as spintronics material

Does automation improve stock market efficiency in Ghana?

The automation of the Ghana Stock Exchange (GSE) in 2008, among other reforms, was expected to improve the efficiency of the market. The extent of this truism has, however, not been empirically established for the GSE. In this study, we attempt to assess the impact of the automation on the efficiency of the GSE within the framework of the weak-form Efficient Market Hypothesis (EMH) based on the before and after approach. The study was done both at the aggregate and micro-level. The aggregate result showed that automation of the exchange did not improve the overall efficiency of the exchange. However, there is evidence that the number of market participants involved in the exchange has increased in the post-automation era. The results of the impact of the automation on the effi ciency of the microstructure are, however, mixed. Generally, the rejection of the null hypothesis under homoscedasticity was found to be robust to heteroscedasticity for some firms, but the reverse was the case for other fi rms. This implies that the rejection of the null hypothesis under homoscedasticity is due to both heteroscedasticity and serial correlation. Based on the findings, a mix of strategies aimed at improving the efficiency of the exchange are recommended.Keywords: automation; stock market efficiency; Ghana Stock Exchang

Positronium reflection and positronium beams

Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 + or - 0.15)A for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbants on it. Two methods for producing Ps beams are described

Multiple Trigger Points for Quantifying Heat-Health Impacts: New Evidence from a Hot Climate

Background: Extreme heat is a public health challenge. The scarcity of directly comparable studies on the association of heat with morbidity and mortality and the inconsistent identification of threshold temperatures for severe impacts hampers the development of comprehensive strategies aimed at reducing adverse heat-health events. Objectives: This quantitative study was designed to link temperature with mortality and morbidity events in Maricopa County, Arizona, USA with a focus on the summer season. Methods: Using Poisson regression models that controlled for temporal confounders, we assessed daily temperature-health associations for a suite of mortality and morbidity events, diagnoses, and temperature metrics. Minimum risk temperatures, increasing risk temperatures, and excess risk temperatures were statistically identified to represent different “trigger points” at which heat-health intervention measures might be activated. Results: We found significant and consistent associations of high environmental temperature with all-cause mortality, cardiovascular mortality, heat-related mortality, and mortality resulting from conditions that are consequences of heat and dehydration. Hospitalizations and emergency department visits due to heat-related conditions and conditions associated with consequences of heat and dehydration were also strongly associated with high temperatures and there were several times more of those events than deaths. For each temperature metric, we observed large contrasts in trigger points (up to 22°C) across multiple health events and diagnoses. Conclusion: Consideration of multiple health events and diagnoses together with a comprehensive approach to identify threshold temperatures revealed large differences in trigger points for possible interventions related to heat. Providing an array of heat trigger points applicable for different end-users may improve public health response to a problem projected to worsen in the coming decades

Experimental study of the role of physicochemical surface processing on the IN ability of mineral dust particles

During the measurement campaign FROST 2 (FReezing Of duST 2), the Leipzig Aerosol Cloud Interaction Simulator (LACIS) was used to investigate the influence of various surface modifications on the ice nucleating ability of Arizona Test Dust (ATD) particles in the immersion freezing mode. The dust particles were exposed to sulfuric acid vapor, to water vapor with and without the addition of ammonia gas, and heat using a thermodenuder operating at 250 °C. Size selected, quasi monodisperse particles with a mobility diameter of 300 nm were fed into LACIS and droplets grew on these particles such that each droplet contained a single particle. Temperature dependent frozen fractions of these droplets were determined in a temperature range between −40 °C ≤T≤−28 °C. The pure ATD particles nucleated ice over a broad temperature range with their freezing behavior being separated into two freezing branches characterized through different slopes in the frozen fraction vs. temperature curves. Coating the ATD particles with sulfuric acid resulted in the particles' IN potential significantly decreasing in the first freezing branch (T>−35 °C) and a slight increase in the second branch (T≤−35 °C). The addition of water vapor after the sulfuric acid coating caused the disappearance of the first freezing branch and a strong reduction of the IN ability in the second freezing branch. The presence of ammonia gas during water vapor exposure had a negligible effect on the particles' IN ability compared to the effect of water vapor. Heating in the thermodenuder led to a decreased IN ability of the sulfuric acid coated particles for both branches but the additional heat did not or only slightly change the IN ability of the pure ATD and the water vapor exposed sulfuric acid coated particles. In other words, the combination of both sulfuric acid and water vapor being present is a main cause for the ice active surface features of the ATD particles being destroyed. A possible explanation could be the chemical transformation of ice active metal silicates to metal sulfates. The strongly enhanced reaction between sulfuric acid and dust in the presence of water vapor and the resulting significant reductions in IN potential are of importance for atmospheric ice cloud formation. Our findings suggest that the IN concentration can decrease by up to one order of magnitude for the conditions investigated

Full potential LAPW calculation of electron momentum density and related properties of Li

Electron momentum density and Compton profiles in Lithium along $$,$$, and $$ directions are calculated using Full-Potential Linear Augmented Plane Wave basis within generalized gradient approximation. The profiles have been corrected for correlations with Lam-Platzman formulation using self-consistent charge density. The first and second derivatives of Compton profiles are studied to investigate the Fermi surface breaks. Decent agreement is observed between recent experimental and our calculated values. Our values for the derivatives are found to be in better agreement with experiments than earlier theoretical results. Two-photon momentum density and one- and two-dimensional angular correlation of positron annihilation radiation are also calculated within the same formalism and including the electron-positron enhancement factor.Comment: 11 pages, 7 figures TO appear in Physical Review

Exploring the knowledge and awareness of diabetes mellitus among inhabitants of Ho municipality in Ghana: A cross-sectional study

One of the fast-growing major non-communicable diseases (NCD) that poses a danger to global public health is Diabetes mellitus (DM). Trends in  the incidence of DM indicate a disproportionate increase in developing countries due to current rapid demographic transitions from traditional to  more westernized and urbanized lifestyles. Knowledge of DM is vital for curbing or control. The objectives of this study were to evaluate the level of  knowledge and awareness of DM among the Ho municipality general population, identify areas of deficiency for targeted health education efforts,  and identify respondent characteristics that may be associated with knowledge of diabetes. A survey involving 132 respondents (age over 18 years)  was conducted in the Ho municipality of the Volta region of Ghana. A 42-item pre-tested questionnaire was administered to participants to evaluate  general and specific knowledge and awareness of DM. The Pairwise Multiple Comparison and Fisher’s Exact tests were used to test the hypotheses  and associations between the respondents’ knowledge level and groups respectively. Of the 132 respondents, 22% were in the age range of 40-46  years; 72.7% were female. Mean over all diabetes knowledge composite score was poor: 32.99% (CI; 27.5, 38.5). Respondents performed best in the  symptoms section: mean score was 36.247% (CI; 29.0, 43.4); and worst in the section on complications: mean score was 30.909% (CI; 23.6, 38.2). In  multiple linear regression analyses, education level, older age, own self having diabetes, and having a family member/relative/friend with diabetes  were significantly associated with knowledge of diabetes. Knowledge of diabetes among the inhabitants of Ho municipality respondents was  interpreted as being inadequate 32.99% (CI; 27.5, 38.5). Some deficient portions and factors associated with knowledge of diabetes were identified.  Relevant information for targeted health education programs in Ghana and beyond may be considered as one of such benefits of these findings.  &nbsp

Genomic Profiling of Childhood Tumor Patient-Derived Xenograft Models to Enable Rational Clinical Trial Design.

Accelerating cures for children with cancer remains an immediate challenge as a result of extensive oncogenic heterogeneity between and within histologies, distinct molecular mechanisms evolving between diagnosis and relapsed disease, and limited therapeutic options. To systematically prioritize and rationally test novel agents in preclinical murine models, researchers within the Pediatric Preclinical Testing Consortium are continuously developing patient-derived xenografts (PDXs)-many of which are refractory to current standard-of-care treatments-from high-risk childhood cancers. Here, we genomically characterize 261 PDX models from 37 unique pediatric cancers; demonstrate faithful recapitulation of histologies and subtypes; and refine our understanding of relapsed disease. In addition, we use expression signatures to classify tumors for TP53 and NF1 pathway inactivation. We anticipate that these data will serve as a resource for pediatric oncology drug development and will guide rational clinical trial design for children with cancer

Corrigendum to "Experimental study of the role of physicochemical surface processing on the IN ability of mineral dust particles" published in Atmos. Chem. Phys., 11, 11131–11144, 2011

In the abstract of the manuscript, the following sentence needs to be corrected: “A possible explanation could be the chemical transformation of ice active metal silicates to metal sulfates.” “metal silicates” is wrong. It should be “aluminosilicates”