2,765 research outputs found
Liquid Metal Sources in Ion Microscopy and Secondary Ion Mass Spectrometry
This paper reports on state-of-the-art developments in liquid metal sources and some of the finer points of their operating characteristics that are especially relevant to the satisfactory functioning of analytical ion scanning microscopes equipped with secondary ion mass spectrometers. Such effects include unwanted emissions from the source and their exclusion by means of filters and mass separators in the ion-optical column. The design of the ion-optical column is also discussed and some applications of this rapidly advancing form of analytical microscopy are described
Measurement of persistence in 1-D diffusion
Using a novel NMR scheme we observed persistence in 1-D gas diffusion. Analytical approximations and numerical simulations have shown that for an initially random array of spins undergoing diffusion, the probability p(t) that the average spin orientation in a given region has not changed sign (i.e., ``persists'') up to time t follows a power law t^{-\theta}, where \theta depends on the dimensionality of the system. The large nuclear spin polarization of laser-polarized 129Xe gas allowed us both to prepare an initial ``quasi-random'' 1-D array of spin orientations and then to perform real-time NMR imaging to monitor the spin diffusion. Our measurements are consistent with theoretical and numerical predictions of \theta ~ 0.12. We also observed finite size effects for long time gas diffusion
Velocity profiles in shear-banding wormlike micelles
Using Dynamic Light Scattering in heterodyne mode, we measure velocity
profiles in a much studied system of wormlike micelles (CPCl/NaSal) known to
exhibit both shear-banding and stress plateau behavior. Our data provide
evidence for the simplest shear-banding scenario, according to which the
effective viscosity drop in the system is due to the nucleation and growth of a
highly sheared band in the gap, whose thickness linearly increases with the
imposed shear rate. We discuss various details of the velocity profiles in all
the regions of the flow curve and emphasize on the complex, non-Newtonian
nature of the flow in the highly sheared band.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let
Improving the normalization of complex interventions: measure development based on normalization process theory (NoMAD): study protocol
<b>Background</b> Understanding implementation processes is key to ensuring that complex interventions in healthcare are taken up in practice and thus maximize intended benefits for service provision and (ultimately) care to patients. Normalization Process Theory (NPT) provides a framework for understanding how a new intervention becomes part of normal practice. This study aims to develop and validate simple generic tools derived from NPT, to be used to improve the implementation of complex healthcare interventions.<p></p>
<b>Objectives</b> The objectives of this study are to: develop a set of NPT-based measures and formatively evaluate their use for identifying implementation problems and monitoring progress; conduct preliminary evaluation of these measures across a range of interventions and contexts, and identify factors that affect this process; explore the utility of these measures for predicting outcomes; and develop an online users’ manual for the measures.<p></p>
<b>Methods</b> A combination of qualitative (workshops, item development, user feedback, cognitive interviews) and quantitative (survey) methods will be used to develop NPT measures, and test the utility of the measures in six healthcare intervention settings.<p></p>
<b>Discussion</b> The measures developed in the study will be available for use by those involved in planning, implementing, and evaluating complex interventions in healthcare and have the potential to enhance the chances of their implementation, leading to sustained changes in working practices
Understanding Polarizing Community Perspectives on Harm Reduction Strategies: Challenges to Addressing the Opioid Crisis in Appalachian Pennsylvania
Introduction: Rural communities face barriers to opioid treatment and overdose prevention including concerns about stigma and lack of harm reduction services.
Purpose: The aim of this study was to explore community perspectives and understanding of harm reduction approaches to opioid use and overdose in a high-risk Northern Appalachian case community in Pennsylvania.
Methods: A small town approximately 10 miles from Pittsburgh was identified as the community with the greatest predicted probabilities of epidemic outbreak using posteriors from spatial models of hospitalizations for opioid use disorders. We interviewed 20 key stakeholders in the case community in using a semi-structured interview guide and analyzed the qualitative data using an inductive grounded theory approach.
Results: Our findings illustrate how conflicting perspectives about opioid dependence lay the foundation for the polarizing community perspectives on addressing opioid use and overdose and general disagreement regarding the legitimacy of harm reduction approaches versus abstinence-based recovery plans. Community members shared varying perspectives on multiple aspects of the opioid epidemic, including appropriate strategies, treatment, and overdose prevention methods and how community leaders and organizations should respond.
Implications: Opinions, coupled with a general lack of education regarding opioid use and harm reduction options, make it challenging for small communities with limited resources to create comprehensive plans to address the opioid crisis
A Hybrid Learning Space for Physically-Active Mathematics: the case of Numberfit
This paper presents the case study of an intervention called
Numberfit that aims at capturing primarily students’ interest in mathematics by combining team games and physical activity. We describe
the hybrid learning space that is created through this approach that
includes an online platform that allows the teachers and facilitators to
design a lesson plan, input student scores and visualise a leaderboard. At
the same time, various digital and tangible resources engage students in
group (collaborative or competitive) activities while practising a range of
topics in mathematics. We examine the changing role of the teacher and
provide some methodological insights for conducting research in relation
to student’s affect, motivation and behaviour in this context
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