897 research outputs found
Spin Resonance and dc Current Generation in a Quantum Wire
We show that in a quantum wire the spin-orbit interaction leads to a narrow
spin resonance at low temperatures, even in the absence of an external magnetic
field. Resonance absorption by linearly polarized radiation gives a dc spin
current; resonance absorption by circularly polarized radiation gives a dc
electric current or magnetization
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On the discovery of K-enhanced and possibly Mg-depleted stars throughout the Milky Way
Stars with unusual elemental abundances offer clues about rare astrophysical
events or nucleosynthetic pathways. Stars with significantly depleted magnesium
and enhanced potassium ([Mg/Fe] 1) have to date only been
found in the massive globular cluster NGC 2419 and, to a lesser extent, NGC
2808. The origin of this abundance signature remains unknown, as does the
reason for its apparent exclusivity to these two globular clusters. Here we
present 112 field stars, identified from 454,180 LAMOST giants, that show
significantly enhanced [K/Fe] and possibly depleted [Mg/Fe] abundance ratios.
Our sample spans a wide range of metallicities (-1.5 < [Fe/H] < 0.3), yet none
show abundance ratios of [K/Fe] or [Mg/Fe] that are as extreme as those
observed in NGC 2419. If confirmed, the identified sample of stars represents
evidence that the nucleosynthetic process producing the anomalous abundances
ratios of [K/Fe] and [Mg/Fe] probably occurs at a wide range of metallicities.
This would suggest that pollution scenarios that are limited to early epochs
(such as Population III supernovae) are an unlikely explanation, although they
cannot be ruled out entirely. This sample is expected to help guide modelling
attempts to explain the origin of the Mg-K abundance signature
Gender, migration and the ambiguous enterprise of professionalizing domestic service: the case of vocational training for the unemployed in France
Drawing on ethnographic data concerning migrant male domestic workers, this article examines the gendered dimensions of the process of racialization in Italy and France. First, it shows that specific racialized constructions of masculinity are mobilized by the employers as well as by training and recruitment agencies. These constructions of masculinity are related to different forms of organization of the sector in each country and to different ideologies about the integration of migrants. Second, the data presented reveal the strategies used by migrant male domestic workers to reaffirm their masculinity in a traditionally feminized sector. In doing so, this article intends to explore the connections between international migration and the gendering of occupations, with regard to the construction and management of masculinities in domestic service. Finally, by examining men’s experiences, this article aims to contribute to a more complex definition of the international division of care work
Corporate Social Responsibility and Islamic Financial Institutions (IFIs): Management Perceptions from IFIs in Bahrain
Islamic finance is gaining greater attention in the finance industry, and this paper analyses how Islamic financial institutions (IFIs) are responding to the welfare needs of society. Using interview data with managers and content analysis of the disclosures, this study attempts to understand management perceptions of corporate social
responsibility (CSR) in IFIs. A thorough understanding of CSR by managers, as evident in the interviews, has not been translated fully into practice. The partial use of IFIs’ potential role in social welfare would add further challenges in the era of financialisation
The local economic development processes in low-income countries: the case of the metropolis of Chegutu in Zimbabwe
Local authorities are widely regarded as catalysts accelerating localised processes of economic development in industrialised countries but in low-income countries they are perceived as dysfunctional, inefficient and ineffective in meeting and addressing societal demands. This abstract view is however, not grounded in empirical research. As such, utilising the case of the metropolis of Chegutu a survey was designed to empirically explicate the economic processes militating its economic development. The findings are useful to policy-makers, local government authorities and management scholars. The study's unique contribution lies in its examination of the processes of local economic development in a low-income country
Drug discovery for Chagas disease should consider Trypanosoma cruzi strain diversity.
This opinion piece presents an approach to standardisation of an important aspect of Chagas disease drug discovery and development: selecting Trypanosoma cruzi strains for in vitro screening. We discuss the rationale for strain selection representing T. cruzi diversity and provide recommendations on the preferred parasite stage for drug discovery, T. cruzi discrete typing units to include in the panel of strains and the number of strains/clones for primary screens and lead compounds. We also consider experimental approaches for in vitro drug assays. The Figure illustrates the current Chagas disease drug-discovery and development landscape
Quantitative analysis of CT-perfusion parameters in the evaluation of brain gliomas and metastases
<p>Abstract</p> <p>Background</p> <p>The paper reports a quantitative analysis of the perfusion maps of 22 patients, affected by gliomas or by metastasis, with the aim of characterizing the malignant tissue with respect to the normal tissue. The gold standard was obtained by histological exam or nuclear medicine techniques. The perfusion scan provided 11 parametric maps, including Cerebral Blood Volume (CBV), Cerebral Blood Flow (CBF), Average Perfusion (P<sub>mean</sub>) and Permeability-surface area product (PS).</p> <p>Methods</p> <p>The perfusion scans were performed after the injection of 40 ml of non-ionic contrast agent, at an injection rate of 8 ml/s, and a 40 s cine scan with 1 s interval was acquired. An expert radiologist outlined the region of interest (ROI) on the unenhanced CT scan, by using a home-made routine. The mean values with their standard deviations inside the outlined ROIs and the contralateral ROIs were calculated on each map. Statistical analyses were used to investigate significant differences between diseased and normal regions. Receiving Operating Characteristic (ROC) curves were also generated.</p> <p>Results</p> <p>Tumors are characterized by higher values of all the perfusion parameters, but after the statistical analysis, only the <it>PS</it>, <it>Pat</it><sub><it>Rsq </it></sub>(Patlak Rsquare) and <it>T</it><sub><it>peak </it></sub>(Time to Peak) resulted significant. ROC curves, confirmed both <it>Pat</it><sub><it>Rsq </it></sub>and <it>PS </it>as equally reliable metrics for discriminating between malignant and normal tissues, with areas under curves (AUCs) of 0.82 and 0.81, respectively.</p> <p>Conclusion</p> <p>CT perfusion is a useful and non invasive technique for evaluating brain neoplasms. Malignant and normal tissues can be accurately differentiated using perfusion map, with the aim of performing tumor diagnosis and grading, and follow-up analysis.</p
Belt restraint reduction in nursing homes: design of a quasi-experimental study
<p>Abstract</p> <p>Background</p> <p>The use of physical restraints still is common practice in the nursing home care. Since physical restraints have been shown to be an ineffective and sometimes even hazardous measure, interventions are needed to reduce their usage. Several attempts have been made to reduce the use of physical restraints. Most studies used educational approaches and introduced a nurse specialist as a consultant. However, the success rate of these interventions has been inconsistent. We developed a new multi-component intervention (EXBELT) comprising an educational intervention for nursing home staff in combination with a policy change (belt use is prohibited by the nursing home management), availability of a nurse specialist and nursing home manager as consultants, and availability of alternative interventions. The first aim of this study is to further develop and test the effectiveness of EXBELT on belt restraint reduction in Dutch psychogeriatric nursing homes. However, the reduction of belts should not result in an increase of other restrictive restraints (such as a chair with locked tray table) or psychoactive drug use. The overall aim is an effective and feasible intervention that can be employed on a large scale in Dutch nursing homes.</p> <p>Methods and design</p> <p>Effects of EXBELT will be studied in a quasi-experimental longitudinal study design. Alongside the effect evaluation, a process evaluation will be carried out in order to further develop EXBELT. Data regarding age, gender, use of physical restraints, the number of falls and fall related injuries, psychoactive drug use, and the use of alternative interventions will be collected at baseline and after four and eight months of follow-up. Data regarding the process evaluation will be gathered in a period of eight months between baseline and the last measurement. Furthermore, changing attitudes will become an important addition to the educational part of EXBELT.</p> <p>Discussion</p> <p>A quasi-experimental study is presented to investigate the effects of EXBELT on the use of belts on wards in psychogeriatric nursing homes. The study will be conducted in 26 wards in 13 psychogeriatric nursing homes. We selected the wards in a manner that contamination between control- and intervention group is prevented.</p> <p>Trial registration</p> <p>(NTR2140)</p
Adapting a Program to Inform African American and Hispanic American Women About Cancer Clinical Trials
The dearth of evidence-based clinical trial education programs may contribute to the underrepresentation of African American and Hispanic American women in cancer research studies. This study used focus group-derived data from 80 women distributed among eight Spanish- and English-language focus groups. These data guided the researchers’ adaptation and refinement of the National Cancer Institute’s various clinical trials education programs into a program that was specifically focused on meeting the information needs of minority women and addressing the barriers to study participation that they perceived. A “sisterhood” theme was adopted and woven throughout the presentation
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