25,362 research outputs found

    The politics of alcohol policy in Nigeria: a critical analysis of how and why brewers use strategic ambiguity to supplant policy initiatives

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    The global call by the World Health Assembly (WHA) to control the rising alcohol-related problems caused by harmful consumption through policy became necessary in 2005 due to the recognition of the fact that many countries did not have alcohol policies. This gave rise to the adoption of a ten-point policy strategy by the World Health Organization (WHO) Member States in 2010. Against this backdrop, many countries adopted alcohol policies to reduce harmful alcohol consumption. Nigeria was one of the WHO Member Countries that adopted the resolution. Nigeria is among the 30 countries with the highest per capita consumption and alcohol-related problems, yet has not formulated alcohol policy to date. This paper draws on Eisenberg’s Strategic Ambiguity Model to explore the role of brewers in supplanting alcohol policy initiatives in Nigeria. It argues that the leading alcohol producers in Nigeria have been the main reason alcohol policies have not been formulated. The article focuses on why their campaigns for responsible drinking, promotions, sponsorships and ‘strategic social responsibilities’ may have increased since the WHA made the call and the WHO adopted the resolution in 2010. It concludes by arguing that there is an urgent need to formulate policies drawing from the WHO resolution to curtail the activities of these brewers and reduce harmful consumption

    Spontaneous Stratification in Granular Mixtures

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    Granular materials size segregate when exposed to external periodic perturbations such as vibrations. Moreover, mixtures of grains of different sizes spontaneously segregate in the absence of external perturbations: when a mixture is simply poured onto a pile, the large grains are more likely to be found near the base, while the small grains are more likely to be near the top. Here, we report a spontaneous phenomenon arising when we pour a mixture between two vertical plates: the mixture spontaneously stratifies into alternating layers of small and large grains whenever the large grains are rougher than the small grains. In contrast, we find only spontaneous segregation when the large grains are more rounded than the small grains. The stratification is related to the occurrence of avalanches; during each avalanche the grains comprising the avalanche spontaneously stratify into a pair of layers through a "kink" mechanism, with the small grains forming a sublayer underneath the layer of large grains.Comment: 4 pages, 6 figures, http://polymer.bu.edu/~hmakse/Home.htm

    A comparison of soil moisture relations between standing and clearfelled plots with burnt and unburnt harvest residue treatments of a clonal eucalypt plantation on the Zululand Coastal Plain, South Africa

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    The effects of clearfelling and subsequent residue retention or burning on water and nutrient balances needs to be understood and quantified on forest sites that are sensitive to loss, so that the long-term sustainable productivity of such sites can be maintained and promoted. An  experimental site was established in a clonal eucalypt compartment on the Zululand Coastal Plain, to compare changes in water fluxes through the mature undisturbed eucalypt stand with those after felling and re-planting, under 2 conditions: burning, and retention of the harvesting residues. The study was located in an area of high rainfall and high stand productivity, with sandy soils and low soil carbon and nutrient status; chosen so that the effects of intensive demands on water and nutrient fluxes on a potentially sensitive site could be investigated. This paper presents only the hydrological component of the study. Data collection included weekly determination of rainfall, throughfall, stemflow and soil moisture fluxes from the surface to a depth of 1 m. Drainage rates through the profile were established using time domain reflectometry probes while water drainage volumes were assessed using shallow plate lysimeters. Despite slow growth in the unfelled crop during the monitoring period (attributed to a pest infestation), soil moisture depletion remained rapid and drainage below 1 m remained low. Soil moisture was recharged within a few months after clearfelling, but became rapidly depleted as the canopy of new crop developed and approached canopy closure. A decreased wetting-front velocity and a marginally higher field capacity were proposed as evidence of pore clogging that appeared to occur during the inter-rotation period. The soil profile under the unburnt residue maintained a marginally higher soil moisture status and lower drainage than the soil profile under the burnt residue. Although soil moisture and drainage in the burnt and unburnt residue treatments became similar to the unfelled crop from canopy closure onwards, rainfall additions to soil moisture were depleted faster under the new crop during the first few months after canopy closure. Small differences in soil moisture status between the burnt and unburnt residue treatments presented here may not be sufficient to influence residue management decisions. The length of the inter-rotation period and practice of residue burning may, however, need consideration where soil carbon and nutrient loss or displacement may negatively affect the sustainability of the site.Keywords: Soil moisture drainage, residue burning, post felling, inter-rotatio

    Compactification on negatively curved manifolds

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    We show that string/M theory compactifications to maximally symmetric space-times using manifolds whose scalar curvature is everywhere negative, must have significant warping, large stringy corrections, or both.Comment: 18 pages, JHEP3.cl

    Large scale predictive process mining and analytics of university degree course data

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    © 2017 ACM. For students, in particular freshmen, the degree pathway from semester to semester is not that transparent, although students have a reasonable idea what courses are expected to be taken each semester. An often-pondered question by students is: "what can I expect in the next semester?" More precisely, given the commitment and engagement I presented in this particular course and the respective performance I achieved, can I expect a similar outcome in the next semester in the particular course I selected? Are the demands and expectations in this course much higher so that I need to adjust my commitment and engagement and overall workload if I expect a similar outcome? Is it better to drop a course to manage expectations rather than to (predictably) fail, and perhaps have to leave the degree altogether? Degree and course advisors and student support units find it challenging to provide evidence based advise to students. This paper presents research into educational process mining and student data analytics in a whole university scale approach with the aim of providing insight into the degree pathway questions raised above. The beta-version of our course level degree pathway tool has been used to shed light for university staff and students alike into our university's 1,300 degrees and associated 6 million course enrolments over the past 20 years

    Electromagnetic Form Factors of the Nucleon and Compton Scattering

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    We review the experimental and theoretical status of elastic electron scattering and elastic low-energy photon scattering (with both real and virtual photons) from the nucleon. As a consequence of new experimental facilities and new theoretical insights, these subjects are advancing with unprecedented precision. These reactions provide many important insights into the spatial distributions and correlations of quarks in the nucleon.Comment: 47 pages, 18 figures, includes corrections and updates to published manuscrip

    RAPD analysis of colchicine induced variation of the Dendrobium Serdang beauty

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    Variation was detected in Dendrobium Serdang Beauty V (DSB V) plantlets regenerated from protocorm like bodies (plbs) induced by various concentration levels of colchicines in the Murashige and Skoog media (MS) supplemented with 1.5 mg/L IBA. RAPD analysis detected 6 - 26% variation in the regenerants from the mother plant. The highest variation was obtained in regenerates treated with 25 mg/L colchicine, which also exhibited reduced regeneration rates from plbs and mean plantlet fresh weight. RAPD analysis also showed high polymorphism between the mutated regenerant DSB V, and 13 species of the Dendrobium genera, and 13 orchids across generas. However, despite the 26% colchicine induced variation in the regenerants, all RAPD analysis revealed that DSB V was closely related to the mother plant. Thus, the RAPD technique is favourable for variation detection as it was sensitive enough to detect variations at species level and among somaclonal variants in this study

    Establishment of a plant regeneration system from callus of Dendrobium cv. Serdang Beauty

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    An in vitro propagation protocol was established for the Dendrobium Serdang Beauty orchid. The propagation protocol utilized calli tissues that were successfully initiated from protocorm-like bodies(PLBs) explants, while the leaf and root tip explants died. The percentage of protocorm-like bodies explants responding to calli formation was 100% in all tested levels of IAA, IBA and NAA auxintreatments. The highest amount of calli (49.59 gram) proliferated on MS medium containing 1.5 mg/L IBA. These calli successfully regenerated on media supplemented with either KIN or BAP cytokinins and combined treatments of KIN and IAA (4 mg/L) or NAA (1.5 mg/L). However, media supplemented with only 1 mg/L KIN was sufficient to produce significantly high percentage of plantlet formation (80%),high number of planlets per explant (4-5 plantlets) and high mean fresh weight per plantlet (11.128 g). These plantlets were acclimatized on all tested media and obtained satisfactory rate of plantlet survival(80-100%), mean number of leaves per plant (4-6 leaves), and mean leaf length (4 - 5 cm). Among these media, charcoal was considered the most economical and available material in the local market. Duringthe development of this protocol, substantial necrosis of calli were observed when cultures were treated with 2,4-D and BAP. It was proposed that the presence of ethylene within the cultures, which isknown to be emitted by plant growth regulators into the micro-climate of in vitro culture vessels, is the determining factor of a suitable plant growth regulator for the survival and growth of the DendrobiumSerdang Beauty calli cultures in our study

    Improved maximum likelihood estimators in a heteroskedastic errors-in-variables model

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    This paper develops a bias correction scheme for a multivariate heteroskedastic errors-in-variables model. The applicability of this model is justified in areas such as astrophysics, epidemiology and analytical chemistry, where the variables are subject to measurement errors and the variances vary with the observations. We conduct Monte Carlo simulations to investigate the performance of the corrected estimators. The numerical results show that the bias correction scheme yields nearly unbiased estimates. We also give an application to a real data set.Comment: 12 pages. Statistical Paper
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