254 research outputs found

    NOURISH, Nutritional OUtcomes from a Randomised Investigation of Intradialytic oral nutritional Supplements in patients receiving Haemodialysis: a pilot randomised controlled trial

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    Background The study was done to assess the feasibility of conducting a trial evaluating the use of an intradialytic oral nutritional supplement (ONS) on nutritional status. Methods The study design is a single centre, parallel group, external pilot randomised controlled trial (RCT). The setting was at a haemodialysis unit in Sheffield, UK. The aim was to recruit 30 trial participants to allow at least 12 evaluable patients per arm, but the actual study sample consisted of 10 adults with a body mass index (BMI) ≤22 kg/m2, receiving thrice weekly haemodialysis. All participants received nutritional advice from a renal dietitian as per usual practice. The intervention included the provision of an intradialytic ONS. Feasibility outcomes included recruitment to time and retention of participants along with palatability of ONS. Secondary outcomes were clinical parameters to obtain variance and estimates of effect size to inform the sample size calculation for a definitive trial. Results Recruitment was undertaken for a fixed period of 6 weeks. Rates were lower than expected mainly due to ineligibility with only 7% of screened patients (19/265) being eligible and 4% (10/265) of these being recruited. Due to the small proportion of patients eligible for the trial, all haemodialysis patients at the specified unit were assessed for eligibility. Data completion rates were low for session questionnaires (23%). Sample sizes derived from variance in secondary outcome measure of handgrip strength and adjusted for a dropout rate of 20% indicate that 189 patients would be required for a definitive RCT, requiring 19 UK haemodialysis units to participate. Conclusions A definitive RCT is feasible with some adaptation to exclusion criteria and methodology. The exclusion criteria could be adapted to include an increase in upper limit for BMI. The use of questionnaires at each dialysis session may not be feasible but the inclusion of appetite and supplement consumption data collection at the main assessments would provide similar outcome data. Quality of life assessment using SF-12 would be acceptable

    Holography from Conformal Field Theory

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    The locality of bulk physics at distances below the AdS length is one of the remarkable aspects of AdS/CFT duality, and one of the least tested. It requires that the AdS radius be large compared to the Planck length and the string length. In the CFT this implies a large-N expansion and a gap in the spectum of anomalous dimensions. We conjecture that the implication also runs in the other direction, so that any CFT with a planar expansion and a large gap has a local bulk dual. For an abstract CFT we formulate the consistency conditions, most notably crossing symmetry, and show that the conjecture is true in a broad range of CFT's, to first nontrivial order in 1/N^2: any CFT with a gap and a planar expansion is generated via the AdS/CFT dictionary from a local bulk interaction. We establish this result by a counting argument on each side, and also investigate various properties of some explicit solutions.Comment: 49 pages. Minor corrections. Figure and references adde

    Nonlocality vs. complementarity: a conservative approach to the information problem

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    A proposal for resolution of the information paradox is that "nice slice" states, which have been viewed as providing a sharp argument for information loss, do not in fact do so as they do not give a fully accurate description of the quantum state of a black hole. This however leaves an information *problem*, which is to provide a consistent description of how information escapes when a black hole evaporates. While a rather extreme form of nonlocality has been advocated in the form of complementarity, this paper argues that is not necessary, and more modest nonlocality could solve the information problem. One possible distinguishing characteristic of scenarios is the information retention time. The question of whether such nonlocality implies acausality, and particularly inconsistency, is briefly addressed. The need for such nonlocality, and its apparent tension with our empirical observations of local quantum field theory, may be a critical missing piece in understanding the principles of quantum gravity.Comment: 11 pages of text and figures, + references. v2 minor text. v3 small revisions to match final journal versio

    Scientific mindfulness: a foundation for future themes in international business

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    We conceptualize new ways to qualify what themes should dominate the future IB research agenda by examining three questions: Whom should we ask? What should we ask and which selection criteria should we apply? What are the contextual forces? We propose scientific mindfulness as the way forward for generating themes in IB research

    Flujo en medio poroso no saturado con conductividad hidráulica discontinua (planteamiento del problema)

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    When studying the flow in an unsaturated porous medium from a point recharge, two phenomena are identified: In the first the residual soil retention conditions are negligible, the mass of water available to flow is constant in time, for So the dimensional analysis considering first order self similarity is sufficient to solve the known diffusion equation. Conversely, if residual soil retention is taken into account, the mass of water available to flow is variable over time because the capillary forces retain some of the water in the pores, so that the mass does not comply with a law Of conservation and the assumption of previous self similarity is not valid. Then another type of self-similar assumption is called the second order, in which the so-called anomalous exponents appear. Under these conditions the equation to be solved is nonlinear with discontinuous coefficient and is called the Baremblatt Equation. The dimensional analysis is not enough to obtain the complete solution one goes to other different techniques, in this case to solve a problem of self value. In the second part will present the numerical solution and the application of this problemCuando se estudia elflujo en un medio poroso no saturado a partir de una recarga puntual, seidentifican dos fenómenos: En el primero las condiciones de retención residual del suelo sondespreciables, la masa de agua disponible para fluir es constante en el tiempo, por lo tanto elanálisis dimensional considerando autosimilaridad de primer orden es suficientepara solucionarla conocida Ecuación de difusión. Por el contrario, si se tiene en cuenta la retención residualdel suelo, la masa de agua disponible para fluir es variable con el tiempo debido a que lasfuerzas de capilaridad retienen parte del agua en los poros, por lo tanto la masa no cumple unaley de conservación y la suposición de autosimilaridad anterior no es válida. Se consideraentonces otro tipo de suposición autosimilar llamada de segundo orden, en la cual aparecen losllamados exponentes anómalos. Bajo estas condiciones la ecuación a solucionar es no linealcon coeficiente discontinuo y recibe el nombre deEcuación de Baremblatt. El análisis dimensionalno es suficientepara obtener la solución completa y se acude a otras técnicas diferentes, en estecaso a resolver un problema de autovalor. En la segunda parte sepresentara la solución numericay la aplicación de este problema

    Non-saturated porous flow with discontinuous hydraulic conductivity 11 numerical solution of the self-problem problem

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    En el problema planteado por Barenblatt y expuesto en la primera parte de este trabajo, seestudia la propagación de una masa de fluido a partir de una inyección. Se muestra la diferenciaque existe en la solución al problema cuando se ignora la retención residual del fluido en elsuelo, en cuyo caso corresponde a la tradicional solución de la ecuación de difusión. Sin embargo,el problema debe plantearse considerando retención residual, lo cual da lugar a un problema deconductividad hidráulica discontinua y debe plantearse una nueva una ley de similaridad queincluye en su forma funcional un exponente anómalo. A partir de las ecuaciones de flujo ycondiciones de frontera se genera un problema de autovalor que en este trabajo es resuelto enforma numérica utilizando un algoritmo combinado de Runge-Kutta y Euler modificado, el cualpermite hallar el exponente en función de los valores de conductividad hidráulica y obtener lasolución completa del problema. Se puede observar la evolución del volumen de fluido, el tiempoy la distancia de propagación de algunos fluidos, considerando o no retención residual en elsuelo.  In the problem posed by Barenblatt and exposed in the first part of this work, the propagation of a mass of fluid from an injection is studied. The difference that exists in the solution to the problem is shown when the residual fluid retention in the soil is ignored, in which case it corresponds to the traditional solution of the diffusion equation. However, the problem must be considered considering residual retention, which gives rise to a problem of discontinuous hydraulic conductivity and a new law of similarity that includes in its functional form an anomalous exponent. From the flow equations and boundary conditions a self-value problem is generated which in this work is solved in numerical form using a combined algorithm of Runge-Kutta and modified Euler, which allows finding the exponent as a function of the values Of hydraulic conductivity and obtain the complete solution of the problem. It is possible to observe the evolution of the volume of fluid, the time and the propagation distance of some fluids, considering or not residual retention in the soil

    Flujo en medio poroso no saturado con conductividad hidráulica discontinua (planteamiento del problema)

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    When studying the flow in an unsaturated porous medium from a point recharge, two phenomena are identified: In the first the residual soil retention conditions are negligible, the mass of water available to flow is constant in time, for So the dimensional analysis considering first order self similarity is sufficient to solve the known diffusion equation. Conversely, if residual soil retention is taken into account, the mass of water available to flow is variable over time because the capillary forces retain some of the water in the pores, so that the mass does not comply with a law Of conservation and the assumption of previous self similarity is not valid. Then another type of self-similar assumption is called the second order, in which the so-called anomalous exponents appear. Under these conditions the equation to be solved is nonlinear with discontinuous coefficient and is called the Baremblatt Equation. The dimensional analysis is not enough to obtain the complete solution one goes to other different techniques, in this case to solve a problem of self value. In the second part will present the numerical solution and the application of this problemCuando se estudia elflujo en un medio poroso no saturado a partir de una recarga puntual, seidentifican dos fenómenos: En el primero las condiciones de retención residual del suelo sondespreciables, la masa de agua disponible para fluir es constante en el tiempo, por lo tanto elanálisis dimensional considerando autosimilaridad de primer orden es suficientepara solucionarla conocida Ecuación de difusión. Por el contrario, si se tiene en cuenta la retención residualdel suelo, la masa de agua disponible para fluir es variable con el tiempo debido a que lasfuerzas de capilaridad retienen parte del agua en los poros, por lo tanto la masa no cumple unaley de conservación y la suposición de autosimilaridad anterior no es válida. Se consideraentonces otro tipo de suposición autosimilar llamada de segundo orden, en la cual aparecen losllamados exponentes anómalos. Bajo estas condiciones la ecuación a solucionar es no linealcon coeficiente discontinuo y recibe el nombre deEcuación de Baremblatt. El análisis dimensionalno es suficientepara obtener la solución completa y se acude a otras técnicas diferentes, en estecaso a resolver un problema de autovalor. En la segunda parte sepresentara la solución numericay la aplicación de este problema

    Systematic techniques for assisting recruitment to trials (START): study protocol for embedded, randomized controlled trials

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    BACKGROUND: Randomized controlled trials play a central role in evidence-based practice, but recruitment of participants, and retention of them once in the trial, is challenging. Moreover, there is a dearth of evidence that research teams can use to inform the development of their recruitment and retention strategies. As with other healthcare initiatives, the fairest test of the effectiveness of a recruitment strategy is a trial comparing alternatives, which for recruitment would mean embedding a recruitment trial within an ongoing host trial. Systematic reviews indicate that such studies are rare. Embedded trials are largely delivered in an ad hoc way, with interventions almost always developed in isolation and tested in the context of a single host trial, limiting their ability to contribute to a body of evidence with regard to a single recruitment intervention and to researchers working in different contexts. METHODS/DESIGN: The Systematic Techniques for Assisting Recruitment to Trials (START) program is funded by the United Kingdom Medical Research Council (MRC) Methodology Research Programme to support the routine adoption of embedded trials to test standardized recruitment interventions across ongoing host trials. To achieve this aim, the program involves three interrelated work packages: (1) methodology - to develop guidelines for the design, analysis and reporting of embedded recruitment studies; (2) interventions - to develop effective and useful recruitment interventions; and (3) implementation - to recruit host trials and test interventions through embedded studies. DISCUSSION: Successful completion of the START program will provide a model for a platform for the wider trials community to use to evaluate recruitment interventions or, potentially, other types of intervention linked to trial conduct. It will also increase the evidence base for two types of recruitment intervention. TRIAL REGISTRATION: The START protocol covers the methodology for embedded trials. Each embedded trial is registered separately or as a substudy of the host trial

    What we talk about when we talk about "global mindset": managerial cognition in multinational corporations

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    Recent developments in the global economy and in multinational corporations have placed significant emphasis on the cognitive orientations of managers, giving rise to a number of concepts such as “global mindset” that are presumed to be associated with the effective management of multinational corporations (MNCs). This paper reviews the literature on global mindset and clarifies some of the conceptual confusion surrounding the construct. We identify common themes across writers, suggesting that the majority of studies fall into one of three research perspectives: cultural, strategic, and multidimensional. We also identify two constructs from the social sciences that underlie the perspectives found in the literature: cosmopolitanism and cognitive complexity and use these two constructs to develop an integrative theoretical framework of global mindset. We then provide a critical assessment of the field of global mindset and suggest directions for future theoretical and empirical research
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