Angular Conditions,Relations between Breit and Light-Front Frames, and Subleading Power Corrections

We analyze the current matrix elements in the general collinear (Breit) frames and find the relation between the ordinary (or canonical) helicity amplitudes and the light-front helicity amplitudes. Using the conservation of angular momentum, we derive a general angular condition which should be satisfied by the light-front helicity amplitudes for any spin system. In addition, we obtain the light-front parity and time-reversal relations for the light-front helicity amplitudes. Applying these relations to the spin-1 form factor analysis, we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light-front time-reversal condition. We make some comments on the consequences of the angular condition for the analysis of the high-$Q^2$ deuteron electromagnetic form factors, and we further apply the general angular condition to the electromagnetic transition between spin-1/2 and spin-3/2 systems and find a relation useful for the analysis of the N-$\Delta$ transition form factors. We also discuss the scaling law and the subleading power corrections in the Breit and light-front frames.Comment: 24 pages,2 figure

Antimatter signals of singlet scalar dark matter

We consider the singlet scalar model of dark matter and study the expected antiproton and positron signals from dark matter annihilations. The regions of the viable parameter space of the model that are excluded by present data are determined, as well as those regions that will be probed by the forthcoming experiment AMS-02. In all cases, different propagation models are investigated, and the possible enhancement due to dark matter substructures is analyzed. We find that the antiproton signal is more easily detectable than the positron one over the whole parameter space. For a typical propagation model and without any boost factor, AMS-02 will be able to probe --via antiprotons-- the singlet model of dark matter up to masses of 600 GeV. Antiprotons constitute, therefore, a promising signal to constraint or detect the singlet scalar model.Comment: 24 pages, 8 figures. v2: minor improvements. Accepted for publication in JCA

Possible Molecular States of Ds∗Dˉs∗D^{*}_s\bar{D}^{*}_s System and Y(4140)

The interpretation of Y(4140) as a $D^{*}_s\bar{D}^{*}_s$ molecule is studied dynamically in the one boson exchange approach, where $\sigma$, $\eta$ and $\phi$ exchange are included. Ten allowed $D^{*}_s\bar{D}^{*}_s$ states with low spin parity are considered, we find that the $J^{PC}=0^{++}$, $1^{+-}$, $0^{-+}$, $2^{++}$ and $1^{--}$ $D^{*}_s\bar{D}^{*}_s$ configurations are most tightly bound. We suggest the most favorable quantum numbers are $J^{PC}=0^{++}$ for Y(4140) as a $D^{*}_s\bar{D}^{*}_s$ molecule, however, $J^{PC}=0^{-+}$ and $2^{++}$ can not be excluded. We propose to search for the $1^{+-}$ and $1^{--}$ partners in the $J/\psi\eta$ and $J/\psi\eta'$ final states, which is an important test of the molecular hypothesis of Y(4140) and the reasonability of our model. The $0^{++}$ $B^{*}_s\bar{B}^{*}_s$ molecule is deeply bound, experimental search in the $\Upsilon(1S)\phi$ channel at Tevatron and LHC is suggested.Comment: 13 pages,2 figure

Granular discharge and clogging for tilted hoppers

We measure the flux of spherical glass beads through a hole as a systematic function of both tilt angle and hole diameter, for two different size beads. The discharge increases with hole diameter in accord with the Beverloo relation for both horizontal and vertical holes, but in the latter case with a larger small-hole cutoff. For large holes the flux decreases linearly in cosine of the tilt angle, vanishing smoothly somewhat below the angle of repose. For small holes it vanishes abruptly at a smaller angle. The conditions for zero flux are discussed in the context of a {\it clogging phase diagram} of flow state vs tilt angle and ratio of hole to grain size

Effectiveness of the Malnutrition eLearning Course for Global Capacity Building in the Management of Malnutrition: Cross-Country Interrupted Time-Series Study.

BACKGROUND: Scaling up improved management of severe acute malnutrition has been identified as the nutrition intervention with the largest potential to reduce child mortality, but lack of operational capacity at all levels of the health system constrains scale-up. We therefore developed an interactive malnutrition eLearning course that is accessible at scale to build capacity of the health sector workforce to manage severely malnourished children according to the guidelines of the World Health Organization. OBJECTIVE: The aim of this study was to test whether the malnutrition eLearning course improves knowledge and skills of in-service and preservice health professionals in managing children with severe acute malnutrition and enables them to apply the gained knowledge and skills in patient care. METHODS: This 2-year prospective, longitudinal, cross-country, interrupted time-series study took place in Ghana, Guatemala, El Salvador, and Colombia between January 2015 and February 2017. A subset of 354 in-service health personnel from 12 hospitals and 2 Ministries of Health, 703 preservice trainees from 9 academic institutions, and 204 online users participated. Knowledge gained after training and retention over time was measured through pre- and postassessments comprising questions pertaining to screening, diagnosis, pathophysiology and treatment, and prevention of malnutrition. Comprehension, application, and integration of knowledge were tested. Changes in perception, confidence, and clinical practice were assessed through questionnaires and interviews. RESULTS: Before the course, awareness of the World Health Organization guidelines was 36.73% (389/1059) overall, and 26.3% (94/358) among in-service professionals. The mean score gain in knowledge after access to the course in 606 participants who had pre- and postassessment data was 11.8 (95% CI 10.8-12.9; P<.001)-a relative increase of 41.5%. The proportion of participants who achieved a score above the pass mark posttraining was 58.7% (356/606), compared with 18.2% (110/606) in pretraining. Of the in-service professionals, 85.9% (128/149) reported applying their knowledge by changing their clinical practice in screening, assessment, diagnosis, and management. This group demonstrated significantly increased retained knowledge 6 months after training (mean difference [SD] from preassessment of 12.1 [11.8]), retaining 65.8% (12.1/18.4) of gained knowledge from the training. Changes in the management of malnutrition were reported by trained participants, and institutional, operational, and policy changes were also found. CONCLUSIONS: The malnutrition eLearning course improved knowledge, understanding, and skills of health professionals in the diagnosis and management of children with severe acute malnutrition, and changes in clinical practice and confidence were reported following the completion of the course

Improved care and survival in severe malnutrition through eLearning.

BACKGROUND: Scaling up improved management of severe acute malnutrition (SAM) has been identified as the nutrition intervention with the greatest potential to reduce child mortality but it requires improved operational capacity. OBJECTIVE: To investigate whether an eLearning course, which can be used at scale in resource-poor countries, leads to improved diagnosis, clinical management and survival of children with SAM. DESIGN: A 2-year preintervention and postintervention study between January 2015 and February 2017. SETTING: Eleven healthcare facilities: nine in Ghana, one in Guatemala, and one in El Salvador. INTERVENTION: Scenario-based eLearning course 'Caring for infants and young children with severe malnutrition'. MAIN OUTCOME MEASURES: Identification of children with SAM, quality of care, case-fatality rate. METHODS: Medical record reviews of children aged 0-60 months attending eleven hospitals between August 2014 and July 2016, observations in paediatric wards, and interviews with senior hospital personnel. RESULTS: Postintervention there was a significant improvement in the identification of SAM: more children had the requisite anthropometric data (34.9% (1300/3723) vs 15.9% (629/3953)) and more were correctly diagnosed (58.5% (460/786) vs 47.1% (209/444)). Improvements were observed in almost all aspects of the WHO 'Ten Steps' of case-management, and case-fatality fell from 5.8% (26/449) to 1.9% (14/745) (Post-pre difference=-3.9%, 95% CI -6.6 to -1.7, p<0.001). CONCLUSIONS: High quality, interactive eLearning can be an effective intervention in scaling up capacity building of health professionals to manage SAM effectively, leading to a reduction in mortality

Combination of two fat saturation pulses improves detectability of glucose signals in carbon-13 MR spectroscopy

In order to improve the fat suppression performance of in vivo 13C-MRS operating at 3.0 Tesla, a phantom model study was conducted using a combination of two fat suppression techniques; a set of pulses for frequency (chemical shift) selective suppression (CHESS), and spatial saturation (SAT). By optimizing the slab thickness for SAT and the irradiation bandwidth for CHESS, the signals of the –13CH3 peak at 49 ppm and the –13CH2– peak at 26 ppm simulating fat components were suppressed to 5% and 19%, respectively. Combination of these two fat suppression pulses achieved a 53% increase of the height ratio of the glucose C1β peak compared with the sum of all other peaks, indicating better sensitivity for glucose signal detection. This method will be applicable for in vivo 13C-MRS by additional adjustment with the in vivo relaxation times of the metabolites

Model-consistent estimation of the basic reproduction number from the incidence of an emerging infection

We investigate the merit of deriving an estimate of the basic reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} early in an outbreak of an (emerging) infection from estimates of the incidence and generation interval only. We compare such estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} with estimates incorporating additional model assumptions, and determine the circumstances under which the different estimates are consistent. We show that one has to be careful when using observed exponential growth rates to derive an estimate of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} , and we quantify the discrepancies that arise

Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters