1,987 research outputs found

    Effect of Pt impurities on the magnetocrystalline anisotropy of hcp Co: a first-principles study

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    In terms of the fully relativistic screened Korringa-Kohn-Rostoker method we investigate the variation in the magnetocrystalline anisotropy energy (MAE) of hexagonal close-packed cobalt with the addition of platinum impurities. In particular, we perform calculations on a bulk cobalt system in which one of the atomic layers contains a fractional, substitutional platinum impurity. Our calculations show that at small concentrations of platinum the MAE is reduced, while at larger concentrations the MAE is enhanced. This change of the MAE can be attributed to an interplay between on-site Pt MAE contributions and induced MAE contributions on the Co sites. The latter ones are subject to pronounced, long-ranged Friedel-oscillations that can lead to significant size effects in the experimental determination of the MAE of nano-sized samples.Comment: 16 page

    Two-divisibility of the coefficients of certain weakly holomorphic modular forms

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    We study a canonical basis for spaces of weakly holomorphic modular forms of weights 12, 16, 18, 20, 22, and 26 on the full modular group. We prove a relation between the Fourier coefficients of modular forms in this canonical basis and a generalized Ramanujan tau-function, and use this to prove that these Fourier coefficients are often highly divisible by 2.Comment: Corrected typos. To appear in the Ramanujan Journa

    Validation of methods for monitoring of coastal and open sea areas with satellites and sensors on ships of opportunity

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    Ã…rsliste 2003Final report to the Norwegian Research Council. The main objective of the project was to construct, install and test an automatic system for observations of temperature, salinity, chlorophyll fluorescence and turbidity from the cooling inlet aboard the ferry Color Festival (Oslo -Hirtshals). An automatic water sampler makes it possible to analyse other properties of the surface water, such as nutrients and organochlorides at selected positions. The potential of combined satellite and ship-sensor observations is illustrated as well as the use of the system for early warning of harmful algea. Examples are also given of the system's potential for low cost high frequency regular monitoring of the surface layer.Norwegian Research Counci

    Patterns of Change in Collaboration Are Associated with Baseline Characteristics and Predict Outcome and Dropout Rates in Treatment of Multi-Problem Families. A Validation Study

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    Objective: The present study validates the Multi-Problem Family (MPF)-Collaboration Scale), which measures the progress of goal directed collaboration of patients in the treatment of families with MPF and its relation to drop-out rates and treatment outcome. Method: Naturalistic study of symptom and competence-related changes in children of ages 4-18 and their caregivers. Setting: Integrative, structural outreach family therapy. Measures: The data of five different groups of goal directed collaboration (deteriorating collaboration, stable low collaboration, stable medium collaboration, stable high collaboration, improving collaboration) were analyzed in their relation to treatment expectation, individual therapeutic goals (ITG), family adversity index, severity of problems and global assessment of a caregiver's functioning, child, and relational aspects. Results: From N=D 810 families, 20% displayed stable high collaboration (n=162) and 21% had a pattern of improving collaboration. The families with stable high or improving collaboration rates achieved significantly more progress throughout therapy in terms of treatment outcome expectancy (d=0.96;r=0.43), reaching ITG (d=1.17;r=0.50), family adversities (d=0.55;r=0.26), and severity of psychiatric symptoms (d=0.31;r=0.15). Furthermore, families with stable high or improving collaboration maintained longer treatments and had a bigger chance of finishing the therapy as planned. The odds of having a stable low or deteriorating collaboration throughout treatment were significantly higher for subjects who started treatment with low treatment expectation or high family-related adversities. Conclusion: The positive outcomes of homebased interventions for multi-problem families are closely related to "stable high" and an "improving" collaboration as measured with the MPF-Collaboration Scale. Patients who fall into these groups have a high treatment outcome expectancy and reduce psychological stress. For therapeutic interventions with multi-problem families it seems beneficial to maintain a stable high collaboration or help the collaboration, e.g., by fostering treatment expectation

    Nuclear structure of Ac-231

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    The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus

    Comparison of blood RNA isolation methods from samples stabilized in Tempus tubes and stored at a large human biobank

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    Additional file 3. Evaluation of reference gene stability. The non-normalized raw Cq-values of reference small ncRNAs for adult (n=12 Tempus tubes) and cord blood (n=3 Tempus tubes) samples collected in the Tempus tubes of the blood-RNA samples isolated using the three RNA isolation protocols

    Hybrid copula mixed models for combining case-control and cohort studies in meta-analysis of diagnostic tests

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    Copula mixed models for trivariate (or bivariate) meta-analysis of diagnostic test accuracy studies accounting (or not) for disease prevalence have been proposed in the biostatistics literature to synthesize information. However, many systematic reviews often include case-control and cohort studies, so one can either focus on the bivariate meta-analysis of the case-control studies or the trivariate meta-analysis of the cohort studies, as only the latter contains information on disease prevalence. In order to remedy this situation of wasting data we propose a hybrid copula mixed model via a combination of the bivariate and trivariate copula mixed model for the data from the case-control studies and cohort studies, respectively. Hence, this hybrid model can account for study design and also due to its generality can deal with dependence in the joint tails. We apply the proposed hybrid copula mixed model to a review of the performance of contemporary diagnostic imaging modalities for detecting metastases in patients with melanoma
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