241 research outputs found

    Tailoring the spectral properties of layered chiral mid-infrared metamaterials

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    This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this recordData availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.The characteristics of four layer chiral metamaterials, optically active in the important mid-infrared region, have been investigated using simulations and experiments. Results show that the spectral response of the materials can be tailored, whilst preserving the magnitude of the circular dichroism, relative to standard double layer metamaterials. An analysis of the coupling in these four layer structures shows that they offer greater design freedom than might be expected from a simple consideration of double layer structures.Engineering and Physical Sciences Research Council (EPSRC

    Boron nitride encapsulated graphene infrared emitters

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    This is the final version of the article. Available from AIP Publishing via the DOI in this record.The spatial and spectral characteristics of mid-infrared thermal emission from devices containing a large area multilayer graphene layer, encapsulated using hexagonal boron nitride, have been investigated. The devices were run continuously in air for over 1000 h, with the emission spectrum covering the absorption bands of many important gases. An approximate solution to the heat equation was used to simulate the measured emission profile across the devices yielding an estimated value of the characteristic length, which defines the exponential rise/fall of the temperature profile across the device, of 40 Ī¼m. This is much larger than values obtained in smaller exfoliated graphene devices and reflects the device geometry, and the increase in lateral heat conduction within the devices due to the multilayer graphene and boron nitride layers.This work has been undertaken as part of an UK Engineering and Physical Sciences Research Council Fellowship (GRN) in Frontier Manufacturing (Grant No. EP/J018651/1)

    To make a difference ā€“ how GPs conceive consultation outcomes. A phenomenographic study

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    <p>Abstract</p> <p>Background</p> <p>Outcomes from GPs' consultations have been measured mainly with disease specific measures and with patient questionnaires about health, satisfaction, enablement and quality. The aim of this study was to explore GPs' conceptions of consultation outcomes.</p> <p>Methods</p> <p>Interviews with 17 GPs in groups and individually about consultation outcomes from recently performed consultations were analysed with a phenomenographic research approach.</p> <p>Results</p> <p>The GPs conceived outcomes in four ways: patient outcomes, GPs' self-evaluation, relationship building and change of surgery routines.</p> <p>Conclusion</p> <p>Patient outcomes, as conceived by the GPs, were generally congruent with those that had been taken up in outcome studies. Relationship building and change of surgery routines were outcomes in preparation for consultations to come. GPs made self-assessments related to internalized norms, grounded on a perceived collegial professional consensus. Considerations of such different aspects of outcomes can inspire professional development.</p

    Task-related oxygen uptake and symptoms during activities of daily life in CHF patients and healthy subjects

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    Patients with chronic heart failure (CHF) have a significantly lower peak aerobic capacity compared to healthy subjects, and, may therefore experience more inconvenience during the performance of domestic activities of daily life (ADLs). To date, the extent to which task-related oxygen uptake, heart rate, ventilation and symptoms during the performance of ADLs in CHF patients is different than in healthy subjects remains uncertain. General demographics, pulmonary function, body composition and peak aerobic capacity were assessed in 23 CHF outpatients and 20 healthy peers. In addition, the metabolic requirement of five simple self-paced domestic ADLs was assessed using a mobile oxycon. Task-related oxygen uptake (ml/min) was similar or lower in CHF patients compared to healthy subjects. In contrast, patients with CHF performing ADLs consumed oxygen at a higher proportion of their peak aerobic capacity than healthy subjects (pĀ <Ā 0.05). For example, getting dressed resulted in a mean task-related oxygen uptake of 49% of peak aerobic capacity, while sweeping the floor resulted in a mean task-related oxygen uptake of 52% of peak aerobic capacity, accompanied by significantly higher Borg symptom scores for dyspnea and fatigue (pĀ <Ā 0.05). Patients with CHF experience use a higher proportion of their peak aerobic capacity, peak ventilation and peak heart rate during the performance of simple self-paced domestic ADL than their healthy peers. These findings represent a necessary step in improving our understanding of improving what troubles patients the mostā€”not being able to do the things that they could when they were healthy

    Using Management Objectives to Specify Management Information Systems - A Contribution to MIS Success

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    Data warehouse projects, today, are in an ambivalent situation. On the one hand, data warehouses are critical for a companyā€™s success and various methodological and technological tools are sophisticatedly developed to implement them. On the other hand, a significant amount of data warehouse projects fails due to non-technical reasons such as insufficient management support or in-corporative employees. But management support and user participation can be increased dramatically with specification methods that are understandable to these user groups. This paper aims at overcoming possible non-technical failure reasons by introducing a user-adequate specification approach within the field of management information systems.\u

    Direct susceptibility testing for multi drug resistant tuberculosis: A meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>One of the challenges facing the tuberculosis (TB) control programmes in resource-limited settings is lack of rapid techniques for detection of drug resistant TB, particularly multi drug resistant tuberculosis (MDR TB). Results obtained with the conventional indirect susceptibility testing methods come too late to influence a timely decision on patient management. More rapid tests directly applied on sputum samples are needed. This study compared the sensitivity, specificity and time to results of four direct drug susceptibility testing tests with the conventional indirect testing for detection of resistance to rifampicin and isoniazid in <it>M. tuberculosis</it>. The four direct tests included two in-house phenotypic assays ā€“ Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS), and two commercially available tests ā€“ Genotype<sup>Ā® </sup>MTBDR and Genotype<sup>Ā® </sup>MTBDR<it>plus </it>(Hain Life Sciences, Nehren, Germany).</p> <p>Methods</p> <p>A literature review and meta-analysis of study reports was performed. The Meta-Disc software was used to analyse the reports and tests for sensitivity, specificity, and area under the summary receiver operating characteristic (sROC) curves. Heterogeneity in accuracy estimates was tested with the Spearman correlation coefficient and Chi-square.</p> <p>Results</p> <p>Eighteen direct DST reports were analysed: NRA ā€“ 4, MODS- 6, Genotype MTBDR<sup>Ā® </sup>ā€“ 3 and Genotype<sup>Ā® </sup>MTBDR<it>plus </it>ā€“ 5. The pooled sensitivity and specificity for detection of resistance to rifampicin were 99% and 100% with NRA, 96% and 96% with MODS, 99% and 98% with Genotype<sup>Ā® </sup>MTBDR, and 99% and 99% with the new Genotype<sup>Ā® </sup>MTBDR<it>plus</it>, respectively. For isoniazid it was 94% and 100% for NRA, 92% and 96% for MODS, 71% and 100% for Genotype<sup>Ā® </sup>MTBDR, and 96% and 100% with the Genotype<sup>Ā® </sup>MTBDR<it>plus</it>, respectively. The area under the summary receiver operating characteristic (sROC) curves was in ranges of 0.98 to 1.00 for all the four tests. Molecular tests were completed in 1 ā€“ 2 days and also the phenotypic assays were much more rapid than conventional testing.</p> <p>Conclusion</p> <p>Direct testing of rifampicin and isoniazid resistance in <it>M. tuberculosis </it>was found to be highly sensitive and specific, and allows prompt detection of MDR TB.</p

    An anthropogenic habitat facilitates the establishment of non-native birds by providing underexploited resources

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    Anthropogenic modification of habitats may reduce the resources available for native species, leading to population declines and extinction. These same habitats often have the highest richness of non-native species. This pattern may be explained if recently human-modified habitats provide novel resources that are more accessible to non-native species than native species. Using non-native birds in the Iberian Peninsula as a case study, we conduct a large-scale study to investigate whether non-native species are positively associated with human modified habitats, and to investigate whether this positive association may be driven by the presence of resources that are not fully exploited by native species. We do this by comparing the functional diversity and resource use of native and non-native bird communities in a recently human-modified habitat (rice fields) and in more traditional habitats in the Iberian Peninsula. The functional diversity of native bird communities was lower in rice fields, but non-native birds were positively associated with rice fields and plugged this gap. Differences in resource use between native and non-native species allowed non-native species to exploit resources that were plentiful in rice fields, supporting the role of underexploited resources in driving the positive association of non-native birds with rice fields. Our results provide a potential mechanism explaining the positive association of non-native species with anthropogenic habitats, and further work is needed to test if this applies more generally

    Dental amalgam and mercury in dentistry

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisherā€™s copy is included.Mercury in dentistry has re-emerged as a contentious issue in public health, predominantly because so many people are inadvertently exposed to mercury in order to obtain the benefits of dental amalgam fillings, and the risks remain difficult to interpret. This commentary aims to examine the issues involved in public policy assessment of the continued use of dental amalgam in dentistry.AJ Spence
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