504 research outputs found

    VLA Limits for Intermediate Mass Black Holes in Three Globular Clusters

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    The observational evidence for central black holes in globular clusters has been argued extensively, and their existence has important consequences for both the formation and evolution of the cluster. Most of the evidence comes from dynamical arguments, but the interpretation is difficult, given the short relaxation times and old ages of the clusters. One of the most robust signatures for the existence of a black hole is radio and/or X-ray emission. We observed three globular clusters, NGC6093 (M80), NGC6266 (M62), and NGC7078 (M15), with the VLA in the A and C configuration with a 3-sigma noise of 36, 36 and 25 microJy, respectively. We find no statistically-significant evidence for radio emission from the central region for any of the three clusters. NGC6266 shows a 2-sigma detection. It is difficult to infer a mass from these upper limits due to uncertainty about the central gas density, accretion rate, and accretion model.Comment: 5 pages, accepted for publication in the Astronomical Journa

    A SIMPLE RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF ORGANIC IMPURITIES, ENANTIOMER AND ASSAY OF DEXLANSOPRAZOLE

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    Objective: To develop a simple and accurate RP-HPLC method for simultaneous estimation of organic impurities, enantiomer and assay of Dexlansoprazole, proposed method was validated according to an International Conference on Harmonisation of technical requirements for registration of pharmaceuticals for human use (ICH) guidelines.Methods: Cellulose tris-(3,5-dichlorophenylcarbamate) bonded on silica gel (Chiralpak IC) were used as stationary phase. Acetonitrile (ACN) and 10 mM dibasic potassium phosphate buffer of pH 7.20, adjusted with dilute ortho phosphoric acid, were used as mobile phase in gradient composition at a flow rate of 1.0 ml/min. UV detection was made at 283 nm and run time was 27 min.Results: Limit of detection (LOD) and Limit of quantification (LOQ) was 42 and 126 ng/ml, respectively. Analytes response was studied from 0.25-1.50 µg/ml and r2 value of the calibration curve was>0.999. Accuracy was studied in three different concentrations, the mean recovery was observed between 93.8 and 102.5%. To the maximum of 0.01% impurity variation was observed between the results of inter and intra-day precision.Conclusion: Proposed method is specific, precise, sensitive, linear and accurate. As a significance of this proposed method, the listed known impurities of Lansoprazole monograph [United States, British and European pharmacopoeias (USP/BP/Ph. Eur.)] Were used in method development and separation was demonstrated. Apart from this, enantiomer resolution was achieved and the same chromatogram was used for assay calculation.Â

    Covert Quantum Communication Over Optical Channels

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    We explore the problem of covertly communicating qubits over the lossy thermal-noise bosonic channel, which is a quantum-mechanical model of many practical channels, including optical. Covert communication ensures that an adversary is unable to detect the presence of transmissions, which are concealed in channel noise. We investigate an achievable lower bound on quantum covert communication using photonic dual-rail qubits. This encoding has practical significance, as it has been proposed for long-range repeater-based quantum communication over optical channels

    Implementation of healthy food environment policies to prevent nutrition-related non-communicable diseases in Ghana : national experts’ assessment of Government action

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    Nutrition-related non-communicable diseases (NR-NCDs) are a global health problem, increasingly recognised as driven by unhealthy food environments. Yet little is known about government action to implement food environment-relevant policies, particularly in low-and lower-middle income countries. This study assessed government action, implementation gaps, and priorities to improve the food environment in Ghana. Using the Healthy Food-Environment Policy Index (Food-EPI), a panel comprising government and independent experts (n = 19) rated government action to improve the healthiness of food environment in Ghana against international best practices and according to steps within a policy cycle. Forty-three good practice indicators of food environment policy and infrastructure support were used, with ratings informed by systematically collected evidence of action validated by government officials. Following the rating exercise, the expert panel proposed and prioritized actions for government implementation. Three-quarters of all good practice indicators were rated at ‘low’/‘very little’ implementation. Restricting the marketing of breast milk substitutes was the only indicator rated “very high”. Of ten policy actions prioritized for implementation, restricting unhealthy food marketing in children’s settings and in the media were ranked the highest priority. Providing sufficient funds for nationally-relevant research on nutrition and NCDs was the highest priority infrastructure-support action. Other priority infrastructure-support actions related to leadership, monitoring and evaluation. This study identified gaps in Ghana’s implementation of internationally-recommended policies to promote healthy food environments. National stakeholders recommended actions, which will require legislation and leadership. The findings provide a baseline for measuring government progress towards implementing effective policies to prevent NR-NCDs

    Good for the planet and good for our health: the evidence for whole-food plant-based diets

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    There is growing interest in the health and environmental benefits of whole-food plant-based (WFPB) diets. The current global food system is harmful to our planet and is a key driver of climate change, pollution and biodiversity loss. A transition to WFPB diets will mitigate against these impacts and potentially reduce greenhouse gas emissions by up to 80%. Emerging evidence suggests that such diets also have significant physical and mental health benefits and can be useful in preventing and treating a range of conditions. Psychiatrists therefore have an important role to play in promoting WFPB diets among patients
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