3,294 research outputs found

    Neutrix Calculus and Finite Quantum Field Theory

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    In general, quantum field theories (QFT) require regularizations and infinite renormalizations due to ultraviolet divergences in their loop calculations. Furthermore, perturbation series in theories like QED are not convergent series, but are asymptotic series. We apply neutrix calculus, developed in connection with asymptotic series and divergent integrals, to QFT,obtaining finite renormalizations. While none of the physically measurable results in renormalizable QFT is changed, quantum gravity is rendered more manageable in the neutrix framework.Comment: 10 pages; LaTeX; version to appear in J. Phys. A: Math. Gen. as a Letter to the Edito

    Evaluation of an adaptive implementation program for cognitive adaptation training for people with severe mental ilness:A cluster-randomized controlled trial

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    Introduction Cognitive Adaptation Training (CAT) is a psychosocial intervention focusing on reducing the impact of cognitive disorders on daily functioning in people with severe mental illness (SMI). Similar to many evidence based practices (EBP), implementation of CAT in routine care lags behind, despite the established effectiveness of the intervention. This so called ‘science-to-service gap’ is a widespread problem in mental health care. We developed an innovative implementation program to facilitate implementation of CAT and similar interventions in routine care. Objectives The aim of this study is to evaluate the effectiveness of the implementation program and to determine factors that impede or facilitate the implementation process. Methods We conducted a multicenter cluster randomized controlled trial comparing the implementation program to a single training program in four mental health institutions (a total of 21 rehabilitation teams) in The Netherlands. Focus groups, semistructured interviews and questionnaires were used at multiple levels of service delivery (service user, professional, team, organization). Assessments took place before, during and after implementation and at follow-up, adding up to a total duration of 14 months. Data were analyzed using multilevel modeling. Results Data collection is complete and analyses on the effectiveness of the implementation program are ongoing. Preliminary analyses show that team climate (p<.008) and organizational climate (p<.043) significantly predict the attitudes of mental health providers toward EBP. Conclusions This implementation research may provide important information about the implementation of psychosocial interventions in practice and may result in a program that is useful for Cognitive Adaptation Training, and possibly for psychosocial interventions in general

    Evaluation of an adaptive implementation program for Cognitive Adaptation Training for people with severe mental illness:Protocol for a randomized controlled trial

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    Background: Cognitive Adaptation Training is a psychosocial intervention that focuses on reducing the negative effects of cognitive disorders, especially executive functions such as planning and targeted action. International research has shown that Cognitive Adaptation Training enhances multiple aspects of daily functioning in people with severe mental illnesses. Despite this evidence, implementation of the intervention into routine care remains a challenge. Objective: In this implementation research, a newly developed implementation program based on previous experience and scientific literature, is tested. The primary aim of this research is to assess the effectiveness of the implementation program. The secondary aim of this study is to evaluate the factors that impede or facilitate the implementation of Cognitive Adaptation Training. Methods: To test the effectiveness of the implementation program, a multicenter cluster randomized controlled trial was conducted comparing the implementation program to a single training program in four mental health institutions in The Netherlands. Focus groups, semistructured interviews, and questionnaires were used at multiple levels of service delivery (service user, professional, team, organization) to identify factors that may hamper or facilitate implementation. The RE-AIM framework was applied to measure the implementation effectiveness. Following this framework, the primary outcomes were Reach, Intervention Effectiveness, Adoption, Implementation, and Maintenance. These are assessed before, during, and after implementation. The research had a total duration of 14 months, with a follow-up measurement at 14 months. Data will be analyzed using multilevel modeling. Results: The study was funded in April 2018. Data collection occurred between November 2018 and January 2020. In total, 21 teams of 4 mental health institutions agreed to participate. Data analysis is ongoing and results are expected to be published in December 2020. Conclusions: This implementation research may provide important information about the implementation of psychosocial interventions in practice and may result in a program that is useful for Cognitive Adaptation Training, and possibly for psychosocial interventions in general. Trial registration: The Netherlands Trial Register (NL7989); https://www.trialregister.nl/trial/7989. International Registered Report Identifier (IRRID): DERR1-10.2196/17412

    Efficient Computation of Three-Dimensional Flow in Helically Corrugated Hoses Including Swirl

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    In this article we propose an efficient method to compute the friction factor of helically corrugated hoses carrying flow at high Reynolds numbers. A comparison between computations of several turbulence models is made with experimental results for corrugation sizes that fall outside the range of validity of the Moody diagram. To do this efficiently we implement quasi-periodicity. Using the appropriate boundary conditions and matching body force, we only need to simulate a single period of the corrugation to find the friction factor for fully developed flow. A second technique is introduced by the construction of an appropriately twisted wedge, which allows us to furthermore reduce the problem by a further dimension while accounting for the Beltrami symmetry that is present in the full three-dimensional problem. We make a detailed analysis of the accuracy and time-saving that this novelty introduces. We show that the swirl inside the flow, which is introduced by the helical boundary, has a positive effect on the friction factor. Furthermore, we give a prediction for which corrugation angles the assumption of axisymmetry is no longer valid. It then has to make place for Beltrami-symmetry if accurate results are required

    “Here’s My Dilemma”. Moral Case Deliberation as a Platform for Discussing Everyday Ethics in Elderly Care

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    Our study presents an overview of the issues that were brought forward by participants of a moral case deliberation (MCD) project in two elderly care organizations. The overview was inductively derived from all case descriptions (N = 202) provided by participants of seven mixed MCD groups, consisting of care providers from various professional backgrounds, from nursing assistant to physician. The MCD groups were part of a larger MCD project within two care institutions (residential homes and nursing homes). Care providers are confronted with a wide variety of largely everyday ethical issues. We distinguished three main categories: ‘resident’s behavior’, ‘divergent perspectives on good care’ and ‘organizational context’. The overview can be used for agendasetting when institutions wish to stimulate reflection and deliberation. It is important that an agenda is constructed from the bottom-up and open to a variety of issues. In addition, organizing reflection and deliberation requires effort to identify moral questions in practice whilst at the same time maintaining the connection with the organizational context and existing communication structures. Once care providers are used to dealing with divergent perspectives, inviting different perspectives (e.g. family members) to take part in the deliberation, might help to identify and address ethical ‘blind spots’

    Metabolic analysis of the interaction between plants and herbivores

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    Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the ‘metabolic interface’. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.

    Strong Pinning in High Temperature Superconductors

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    Detailed measurements of the critical current density jc of YBa2Cu3O7 films grown by pulsed laser deposition reveal the increase of jc as function of the filmthickness. Both this thickness dependence and the field dependence of the critical current are consistently described using a generalization of the theory of strong pinning of Ovchinnikov and Ivlev [Phys. Rev. B 43, 8024 (1991)]. From the model, we deduce values of the defect density (10^21 m^-3) and the elementary pinning force, which are in good agreement with the generally accepted values for Y2O3-inclusions. In the absence of clear evidence that the critical current is determined by linear defects or modulations of the film thickness, our model provides an alternative explanation for the rather universal field dependence of the critical current density found in YBa2Cu3O7 films deposited by different methods.Comment: 11 pages; 8 Figures; Published Phys. Rev. B 66, 024523 (2002
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