332 research outputs found

    Local and Nonlocal Dispersive Turbulence

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    We consider the evolution of a family of 2D dispersive turbulence models. The members of this family involve the nonlinear advection of a dynamically active scalar field, the locality of the streamfunction-scalar relation is denoted by α\alpha, with smaller α\alpha implying increased locality. The dispersive nature arises via a linear term whose strength is characterized by a parameter ϵ\epsilon. Setting 0<ϵ≤10 < \epsilon \le 1, we investigate the interplay of advection and dispersion for differing degrees of locality. Specifically, we study the forward (inverse) transfer of enstrophy (energy) under large-scale (small-scale) random forcing. Straightforward arguments suggest that for small α\alpha the scalar field should consist of progressively larger eddies, while for large α\alpha the scalar field is expected to have a filamentary structure resulting from a stretch and fold mechanism. Confirming this, we proceed to forced/dissipative dispersive numerical experiments under weakly non-local to local conditions. For ϵ∼1\epsilon \sim 1, there is quantitative agreement between non-dispersive estimates and observed slopes in the inverse energy transfer regime. On the other hand, forward enstrophy transfer regime always yields slopes that are significantly steeper than the corresponding non-dispersive estimate. Additional simulations show the scaling in the inverse regime to be sensitive to the strength of the dispersive term : specifically, as ϵ\epsilon decreases, the inertial-range shortens and we also observe that the slope of the power-law decreases. On the other hand, for the same range of ϵ\epsilon values, the forward regime scaling is fairly universal.Comment: 19 pages, 8 figures. Significantly revised with additional result

    Two-dimensional Moist Stratified Turbulence and the Emergence of Vertically Sheared Horizontal Flows

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    Moist stratified turbulence is studied in a two-dimensional Boussinesq system influenced by condensation and evaporation. The problem is set in a periodic domain and employs simple evaporation and condensation schemes, wherein both the processes push parcels towards saturation. Numerical simulations demonstrate the emergence of a moist turbulent state consisting of ordered structures with a clear power-law type spectral scaling from initially spatially uncorrelated conditions. An asymptotic analysis in the limit of rapid condensation and strong stratification shows that, for initial conditions with enough water substance to saturate the domain, the equations support a straightforward state of moist balance characterized by a hydrostatic, saturated, vertically sheared horizontal flow (VSHF). For such initial conditions, by means of long time numerical simulations, the emergence of moist balance is verified. Specifically, starting from uncorrelated data, subsequent to the development of a moist turbulent state, the system experiences a rather abrupt transition to a regime which is close to saturation and dominated by a strong VSHF. On the other hand, initial conditions which do not have enough water substance to saturate the domain, do not attain moist balance. Rather, the system remains in a turbulent state and oscillates about moist balance. Even though balance is not achieved with these general initial conditions, the time scale of oscillation about moist balance is much larger than the imposed time scale of condensation and evaporation, thus indicating a distinct dominant slow component in the moist stratified two-dimensional turbulent system.Comment: 23 pages. 9 figure

    Investing in breastfeeding – the world breastfeeding costing initiative

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    BACKGROUND Despite scientific evidence substantiating the importance of breastfeeding in child survival and development and its economic benefits, assessments show gaps in many countries' implementation of the 2003 WHO and UNICEF Global Strategy for Infant and Young Child Feeding (Global Strategy). Optimal breastfeeding is a particular example: initiation of breastfeeding within the first hour of birth, exclusive breastfeeding for the first six months; and continued breastfeeding for two years or more, together with safe, adequate, appropriate, responsive complementary feeding starting in the sixth month. While the understanding of "optimal" may vary among countries, there is a need for governments to facilitate an enabling environment for women to achieve optimal breastfeeding. Lack of financial resources for key programs is a major impediment, making economic perspectives important for implementation. Globally, while achieving optimal breastfeeding could prevent more than 800,000 under five deaths annually, in 2013, US58billionwasspentoncommercialbabyfoodincludingmilkformula.Supportforimprovedbreastfeedingisinadequatelyprioritizedbypolicyandpracticeinternationally.METHODSTheWorldBreastfeedingCostingInitiative(WBCi)launchedin2013,attemptstodeterminethefinancialinvestmentthatisnecessarytoimplementtheGlobalStrategy,andtointroduceatooltoestimatethecostsforindividualcountries.ThearticlepresentsdetailedcostestimatesforimplementingtheGlobalStrategy,andoutlinestheWBCiFinancialPlanningTool.EstimatesusedemographicdatafromUNICEF′sStateoftheWorld′sChildren2013.RESULTSTheWBCitakesaprogrammaticapproachtoscalingupinterventions,includingpolicyandplanning,healthandnutritioncaresystems,communityservicesandmothersupport,mediapromotion,maternityprotection,WHOInternationalCodeofMarketingofBreastmilkSubstitutesimplementation,monitoringandresearch,foroptimalbreastfeedingpractices.ThefinancialcostofaprogramtoimplementtheGlobalStrategyin214countriesisestimatedatUS58 billion was spent on commercial baby food including milk formula. Support for improved breastfeeding is inadequately prioritized by policy and practice internationally. METHODS The World Breastfeeding Costing Initiative (WBCi) launched in 2013, attempts to determine the financial investment that is necessary to implement the Global Strategy, and to introduce a tool to estimate the costs for individual countries. The article presents detailed cost estimates for implementing the Global Strategy, and outlines the WBCi Financial Planning Tool. Estimates use demographic data from UNICEF's State of the World's Children 2013. RESULTS The WBCi takes a programmatic approach to scaling up interventions, including policy and planning, health and nutrition care systems, community services and mother support, media promotion, maternity protection, WHO International Code of Marketing of Breastmilk Substitutes implementation, monitoring and research, for optimal breastfeeding practices. The financial cost of a program to implement the Global Strategy in 214 countries is estimated at US 17.5 billion ($130 per live birth). The major recurring cost is maternity entitlements. CONCLUSIONS WBCi is a policy advocacy initiative to encourage integrated actions that enable breastfeeding. WBCi will help countries plan and prioritize actions and budget them accurately. International agencies and donors can also use the tool to calculate or track investments in breastfeeding.The project was possible through financial support from SAFANSI (South Asia Food and Nutrition Security Initiative) project and a contribution by DFID (Department for International Development) and AusAID (Australian Agency for International Development)

    Our Story Interview Questions (Tentative)

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    This list includes the intended questions to be asked during the interview sessions

    Exploring Strategic Organizational Engagement in Social Media: A Revelatory Case

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    There has been little theorizing in information systems (IS) or management literature to inform organizational strategies for social media engagement. Aral et al. (2013) lament the dearth of scholarly work focused on understanding organizations’ high-level social media strategies. In this research, we describe our case research to develop an empirically informed understanding of strategic organizational engagement in social media to advance organizational goals. We present an in-depth case study of strategic social media engagement at a successful multi-national business and IT consulting firm who routinely develops and deploys social media strategies to advance organizational goals. We situate our interpretation in the dynamic capabilities perspective, and present a revelatory case well-suited to developing an empirically-informed understanding of strategic social media engagement to advance organizational goals. We develop an analytic perspective of social media based as social systems, and describe topical collectivities as strategically important members of their ontology

    A Case of Soft Tissue Myoepithelial Tumor Arising in Masticator Space

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    Soft tissue myoepithelial tumors of the head and neck region are very rare, and only one case of soft tissue myoepithelial tumor occurring in the masticator space has been reported in the world literature. A case of soft tissue myoepithelial tumor with benign histomorphology, but with an invasive growth pattern, occurred in the masticator space of a 46-year- old male patient. Magnetic resonance imaging of paranasal sinus/nasopharynx revealed a well-defined, lobulated heterogeneous mass with high signal intensity and dense calcification in the masticator space between the left mandible ramus and pterygoid process. Grossly, the tumor was a well-circumscribed ovoid solid mass and consisted of yellowish gray glistening firm tissue. Histologically, the tumor showed a multinodular growth pattern and consisted of epithelioid cells in chondromyxoid stroma and of spindle-shaped to ovoid cells in the hyaline stroma. The tumor cells appeared bland, and no mitosis or necrosis was found within the tumor. The tumor focally invaded to adhered bone tissue. Immunohistochemically, the tumor cells were diffusely positive for epithelial membrane antigen, smooth muscle actin, but negative for other epithelial markers. Ultrastructurally, the cytoplasm of the tumor cells contained sparse microfilaments and subplasmalemmal densities. Attenuated desmosomes were commonly seen between the tumor cells

    Optimal iron content in ready-to-use therapeutic foods for the treatment of severe acute malnutrition in the community settings: A protocol for the systematic review and meta-analysis

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    Introduction: The current standard of care for children with severe acute malnutrition (SAM) involves using ready-to-use therapeutic food (RUTF) to promote growth; however, the precise formulation to achieve optimal recovery remains unclear. Emerging research suggests that alternative RUTF formulations may be more effective in correcting SAM-related complications such as anaemia and iron deficiency. This systematic review commissioned by the WHO aims to synthesise the most recent research on the iron content in RUTF and related products in the community-based treatment of uncomplicated severe malnutrition in children aged 6 months and older. Methods and analysis: We will search multiple electronic databases. We will include randomised controlled trials and non-randomised studies with a control arm. The intervention group will be infants who received RUTF treatments other than the current recommended guidelines set forth by the WHO. The comparison group is children receiving RUTF containing iron at the current WHO-recommended level of 1.9 mg/100 kcal (10-14 mg/100 g). The primary outcomes of interest include blood haemoglobin concentration, any anaemia, severe anaemia, iron-deficiency anaemia, recovery from SAM and any adverse outcomes. We will use meta-analysis to pool findings if sufficient homogeneity exists among included studies. The risk of bias in studies will be evaluated using the Cochrane risk of bias-2. We will use the Grading of Recommendations Assessment, Development, and Evaluation(GRADE) approach to examine the overall certainty of evidence. Ethics and dissemination: This is a systematic review and will not involve direct contact with human subjects. The findings of this review will be published in a peer-reviewed journal and will guide the WHO\u27s recommendation on the optimal iron content in RUTFs for the treatment of SAM in children aged 6-59 month
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