4,396 research outputs found

    Model-free reconstruction of magnetic correlations in frustrated magnets

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    Frustrated magnetic systems exhibit extraordinary physical properties but quantification of their magnetic correlations poses a serious challenge to experiment and theory. Current insight into frustrated magnetic correlations relies on modelling techniques such as reverse Monte Carlo methods, which require knowledge about the exact ordered atomic structure. Here we present a method for direct reconstruction of magnetic correlations in frustrated magnets by three-dimensional difference pair distribution function analysis of neutron total scattering data. The methodology is applied to the disordered frustrated magnet bixbyite, (Mn1-xFex)2O3, which reveals nearest-neighbor antiferromagnetic correlations for the metal sites up to a range of approximately 15 {\AA}. Importantly, this technique allows for magnetic correlations to be determined directly from the experimental data without any assumption about the atomic structure

    Unchanged thermopower enhancement at the semiconductor-metal transition in correlated FeSb2−x_{2-x}Tex_x

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    Substitution of Sb in FeSb2_2 by less than 0.5% of Te induces a transition from a correlated semiconductor to an unconventional metal with large effective charge carrier mass m∗m^*. Spanning the entire range of the semiconductor-metal crossover, we observed an almost constant enhancement of the measured thermopower compared to that estimated by the classical theory of electron diffusion. Using the latter for a quantitative description one has to employ an enhancement factor of 10-30. Our observations point to the importance of electron-electron correlations in the thermal transport of FeSb2_2, and suggest a route to design thermoelectric materials for cryogenic applications.Comment: 3 pages, 3 figures, accepted for publication in Appl. Phys. Lett. (2011

    How 25 years of psychosocial research has contributed to a better understanding of the links between depression and diabetes

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    This narrative review of the literature provides a summary and discussion of 25 years of research into the complex links between depression and diabetes. Systematic reviews have shown that depression occurs more frequently in people with type 1 or type 2 diabetes compared with people without diabetes. Currently, it remains unclear whether depression is also more common in people with impaired glucose metabolism or undiagnosed type 2 diabetes compared with people without diabetes. More prospective epidemiological research into the course of depression and an exploration of mechanisms in individuals with diabetes are needed.Depression in diabetes is associated with less optimal self-care behaviours, suboptimal glycaemic control, impaired quality of life, incident micro- and macrovascular diseases, and elevated mortality rates. Randomized controlled trails concluded that depression in diabetes can be treated with antidepressant medication, cognitive–behavioural therapy (individual, group-based or web-based), mindfulness-based cognitive therapy and stepped care. Although big strides forward have been made in the past 25 years, scientific evidence about depression in diabetes remains incomplete. Future studies should investigate mechanisms that link both conditions and test new diabetes-specific web- or app-based interventions for depression in diabetes. It is important to determine whether treatment or prevention of depression prevents future diabetes complications and lowers mortality rates

    How Much Do We Count? Interpretation and Error-Making in the Decennial Census

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    Following a critique of the 1990 decennial census procedures, we conducted a field study among low-income, inner-city residents in 1991 to examine how they conceptualized and managed the civic task of census response. Interpretations about the purpose and meaning of the census, about commitment to the task, and about connection to government, singly and together with literacy skills (e.g., reading and general literacy competence), were associated with errors that are not detectable by evaluative methodologies used regularly by the Census Bureau. The validity and reliability of census data, and possibly other self-administered survey research, will be increased by greater use of knowledge about both interpretation and literacy skills in formulating data collection procedures

    Hypothalamically-Induced Insulin Release and its Potentiation During Oral and Intravenous Glucose Loads

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    Male Wistar rats were provided with bilateral cannulas in the lateral hypothalamic area (LHA) and cannulas in the left and right jugular vein. Freely moving rats provided in this way with cannulas were infused with transmitters in the LHA and with various substances in the blood circulation during simultaneous sampling of blood without disturbing the animals. Infusion of norepinephrine (NE) in the LHA resulted in increased insulin levels while plasma glucagon and blood glucose were nearly not affected. This LHA mediated insulin release was suppressed by atropine injection in the blood circulation suggesting a vagal contribution to the observed phenomenon. Administration of either an oral or i.v. glucose load during noradrenergic stimulation of the LHA elicited an exaggerated insulin response when compared to their controls. This LHA potentiated insulin response during an oral and i.v. glucose load could be suppressed by atropinization of the rats. It is concluded that meal-related stimuli are relayed to the NE-stimulated area of the LHA and that these stimuli modulate the output from this area of the LHA that is concerned with the release of insulin.

    Microfungal contamination of damp buildings--examples of risk constructions and risk materials.

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    To elucidate problems with microfungal infestation in indoor environments, a multidisciplinary collaborative pilot study, supported by a grant from the Danish Ministry of Housing and Urban Affairs, was performed on 72 mold-infected building materials from 23 buildings. Water leakage through roofs, rising damp, and defective plumbing installations were the main reasons for water damage with subsequent infestation of molds. From a score system assessing the bioavailability of the building materials, products most vulnerable to mold attacks were water damaged, aged organic materials containing cellulose, such as wooden materials, jute, wallpaper, and cardboard. The microfungal genera most frequently encountered were Penicillium (68%), Aspergillus (56%), Chaetomium (22%), Ulocladium, (21%), Stachybotrys (19%) and Cladosporium (15%). Penicillium chrysogenum, Aspergillus versicolor, and Stachybotrys chartarum were the most frequently occurring species. Under field conditions, several trichothecenes were detected in each of three commonly used building materials, heavily contaminated with S. chartarum. Under experimental conditions, four out of five isolates of S. chartarum produced satratoxin H and G when growing on new and old, very humid gypsum boards. A. versicolor produced the carcinogenic mycotoxin sterigmatocystin and 5-methoxysterigmatocystin under the same conditions

    Care pathways in the transition of patients between district psychiatric hospital centres (DPCs) and community mental health services

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    Rationale, aims, and objectives: Patients with mental health problems experience numerous transitions into and out of the hospital. Primary care providers have mixed success in identifying and managing patients' needs. This study explores health personnel’s experience of care pathways in patient transition between inpatient and community mental health services. Method: A descriptive qualitative design was chosen. Four focus group interviews with twelve informants from seven different communities were conducted. Interviews were analyzed thematically. Results: Two main themes were identified: integrated care and patient activation. The participants shared their experiences on topics that can affect smooth care pathways in mental health. Six promoting factors were identified for successful patient transition: opportunities for information sharing, implementation of systematic plans, use of e-messages, around-the-clock care, designating one responsible health person in each system for each patient, and the involvement of patients and their families. The following barriers were all found to impede the patients’ transition between levels of care: the lack of a single responsible person at each health care level, insufficient meetings, the absence of systematic plans, difficulties in identifying the right staff at different levels, delays in information sharing, and the complexity of welfare systems negatively affecting patient dignity. Conclusions: Systems and procedures should be developed to ensure clear responsibilities and transparency at each stage of the pathways of care. A single person should take charge of ensuring sufficient connection and communication between inpatient and community mental health services. Finally, both patient and staff in community services should be linked through a direct telephone number with around-the-clock availability
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