954 research outputs found

    The existence of an inverse limit of inverse system of measure spaces - a purely measurable case

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    The existence of an inverse limit of an inverse system of (probability) measure spaces has been investigated since the very beginning of the birth of the modern probability theory. Results from Kolmogorov [10], Bochner [2], Choksi [5], Metivier [14], Bourbaki [3] among others have paved the way of the deep understanding of the problem under consideration. All the above results, however, call for some topological concepts, or at least ones which are closely related topological ones. In this paper we investigate purely measurable inverse systems of (probability) measure spaces, and give a sucient condition for the existence of a unique inverse limit. An example for the considered purely measurable inverse systems of (probability) measure spaces is also given

    Wave interactions in neutrally stable shear layers:regular and singular modes, and non-modal growth

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    In a recent letter, Carpenter and Guha (2019) compared the neutral modes of a smooth two dimensional shear profile without an inflection point to the modes of its corresponding piecewise-linear profile. The regular mode in the smooth profile was identified as the one least sensitive to the numerical resolution, while the singular modes displayed high sensitivity. Here we provide a physical interpretation using a wave interaction approach for understanding the structure and behavior of both the regular and singular modes. The regular modes are the interfacial Rossby waves located at the concentrated mean vorticity gradient of the shear profile. In contrast, the singular modes result from a one way phase-locking interaction between singular vorticity disturbances, passively advected by the mean flow at different levels of the profile, and the interfacial Rossby waves. We show that this one way interaction can also lead to a sustained non-modal growth of the interfacial Rossby waves that cannot be captured by standard eigenvalue analysis

    Leading Boldly: Foundations Can Move Past Traditional Approaches to Create Social Change Through Imaginative -- Even Controversial -- Leadership

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    Rarely do foundations publicly communicate their dissatisfaction with their grantees, withhold funds, or use tactics that carry the risks of creating ill will. Yet extraordinary results can be achieved if foundations were more imaginative, visible, and controversial. Three foundations shocked the city of Pittsburgh in 2002 by abruptly suspending their funding to local public schools. The foundations announced their decision in a news conference that attracted both local and national coverage -- a sharp departure from their usual approach of working quietly behind the scenes. Foundation executives explained that they had completely lost confidence in the ability of the local school board to run the district. Their action yielded a community-wide process that led to real change. Here's how foundations can exercise Adaptive Leadership without misusing authority

    Zero absolute vorticity plane Couette flow as an hydrodynamic representation of quantum energy states under perpendicular magnetic field

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    Here we extend the Madelung transformation of the Schr\"{o}dinger equation into a fluid-like form to include the influence of an external electromagnetic field on a charged particle. The vorticity of the Madelung fluid is then in the opposite direction to the imposed magnetic field and equal in magnitude to the cyclotron angular frequency. When the particle motion is confined to a plane, perpendicular to an imposed magnetic field, the equivalent flow dynamics is that of zero absolute vorticity obtained in a quasi 2D rotating frame, where the cyclotron frequency plays a role equivalent to that of the Coriolis frequency in a rotating frame. We show how the Landau levels and the extended modes in the integer quantum Hall effect are all mapped into such zero absolute vorticity-like plane Couette flows, where the latter exhibit a geostrophic-like balance between the magnetic force and the gradients of the quantum (Bohm) potential and the electric force.Comment: 17 pages, 3 figures; preprint version here; published in Physics of Fluid

    A New Deal for Global Health R&D? The Recommendations of the Consultative Expert Working Group on Research and Development (CEWG)

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    John-Arne Røttingen and Claudia Chamas, chairs of the the Consultative Expert Working Group on Research and Development (CEWG), summarize their recent report recommending to the World Health Assembly that a global health R&D treaty be developed

    The influence of adaptive challenge on engagement of multidisciplinary staff in standardising aseptic technique in an emergency department: A qualitative study

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    Aims and objectives: To explore the challenge of engaging multidisciplinary staff in standardising aseptic technique (AT) in an emergency department (ED) in an Australian tertiary hospital, and to better understand the enablers and barriers to implementing practice change within this setting. Background: Healthcare‐associated infections are the most common complication for patients in acute care. A clinical practice framework developed in the United Kingdom (UK) standardised AT practice to reduce potential infection risk. One Australian tertiary hospital drew upon this framework to similarly improve clinical practice. It was understood that standardising practice would require some practitioners only to revisit and demonstrate AT principles already embedded in their practice, while others would be challenged to adopt a new approach. Design: Qualitative, descriptive research design. Methods: Data were collected through focus groups held before and after implementation of the AT programme. Data were analysed using the framework method. The (COREQ) checklist was followed. Results: Four emergent themes described the influence of motivation on individuals\u27 beliefs and attitudes towards practice change, relationships within the ED context, delivery of education and management directives. Conclusion: Implementing practice change is more than just providing technical knowledge and includes changing individuals\u27 beliefs and attitudes. An understanding of adaptive challenge can assist in implementing practice change that involves the multidisciplinary team. Relevance to clinical practice: Results provide evidence as to how the adaptive challenge framework could be a suitable approach to manage potential enablers and barriers to implementing change within a multidisciplinary team in an acute hospital

    Tissue remodeling: a mating-induced differentiation program for the Drosophila oviduct

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    <p>Abstract</p> <p>Background</p> <p>In both vertebrates and invertebrates, the oviduct is an epithelial tube surrounded by visceral muscles that serves as a conduit for gamete transport between the ovary and uterus. While <it>Drosophila </it>is a model system for tubular organ development, few studies have addressed the development of the fly's oviduct. Recent studies in <it>Drosophila </it>have identified mating-responsive genes and proteins whose levels in the oviduct are altered by mating. Since many of these molecules (e.g. Muscle LIM protein 84B, Coracle, Neuroglian) have known roles in the differentiation of muscle and epithelia of other organs, mating may trigger similar differentiation events in the oviduct. This led us to hypothesize that mating mediates the last stages of oviduct differentiation in which organ-specific specializations arise.</p> <p>Results</p> <p>Using electron- and confocal-microscopy we identified tissue-wide post-mating changes in the oviduct including differentiation of cellular junctions, remodeling of extracellular matrix, increased myofibril formation, and increased innervation. Analysis of once- and twice-mated females reveals that some mating-responsive proteins respond only to the first mating, while others respond to both matings.</p> <p>Conclusion</p> <p>We uncovered ultrastructural changes in the mated oviduct that are consistent with the roles that mating-responsive proteins play in muscle and epithelial differentiation elsewhere. This suggests that mating triggers the late differentiation of the oviduct. Furthermore, we suggest that mating-responsive proteins that respond only to the first mating are involved in the final maturation of the oviduct while proteins that remain responsive to later matings are also involved in maintenance and ongoing function of the oviduct. Taken together, our results establish the oviduct as an attractive system to address mechanisms that regulate the late stages of differentiation and maintenance of a tubular organ.</p

    Rapid and Accurate Assessment of GPCR-Ligand Interactions Using the Fragment Molecular Orbital-Based Density-Functional Tight-Binding Method

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    The reliable and precise evaluation of receptor–ligand interactions and pair-interaction energy is an essential element of rational drug design. While quantum mechanical (QM) methods have been a promising means by which to achieve this, traditional QM is not applicable for large biological systems due to its high computational cost. Here, the fragment molecular orbital (FMO) method has been used to accelerate QM calculations, and by combining FMO with the density-functional tight-binding (DFTB) method we are able to decrease computational cost 1000 times, achieving results in seconds, instead of hours. We have applied FMO-DFTB to three different GPCR–ligand systems. Our results correlate well with site directed mutagenesis data and findings presented in the published literature, demonstrating that FMO-DFTB is a rapid and accurate means of GPCR–ligand interactions

    Government support for faith-based organizations: the case of a development programme for faith leaders

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    A government initiative to train faith leaders usefully extended existing provision, but will require continuing support for some years. Broader community leadership is not always expected from those holding religious positions. The challenges involved in bridging linguistic and cultural differences highlight some of the reasons why initiatives like this are needed

    Strong Completeness for Markovian Logics

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    In this paper we present Hilbert-style axiomatizations for three logics for reasoning about continuous-space Markov processes (MPs): (i) a logic for MPs defined for probability distributions on measurable state spaces, (ii) a logic for MPs defined for sub-probability distributions and (iii) a logic defined for arbitrary distributions.These logics are not compact so one needs infinitary rules in order to obtain strong completeness results. We propose a new infinitary rule that replaces the so-called Countable Additivity Rule (CAR) currently used in the literature to address the problem of proving strong completeness for these and similar logics. Unlike the CAR, our rule has a countable set of instances; consequently it allows us to apply the Rasiowa-Sikorski lemma for establishing strong completeness. Our proof method is novel and it can be used for other logics as well
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