573 research outputs found

    On-chip manipulation of single photons from a diamond defect

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    Operating reconfigurable quantum circuits with single photon sources is a key goal of photonic quantum information science and technology. We use an integrated waveguide device containing directional couplers and a reconfigurable thermal phase controller to manipulate single photons emitted from a chromium related color center in diamond. Observation of both a wavelike interference pattern and particlelike sub-Poissionian autocorrelation functions demonstrates coherent manipulation of single photons emitted from the chromium related center and verifies wave particle duality. © 2013 American Physical Society

    Delocalized single-photon Dicke states and the Leggett- Garg inequality in solid state systems

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    We show how to realize a single-photon Dicke state in a large one-dimensional array of two- level systems, and discuss how to test its quantum properties. Realization of single-photon Dicke states relies on the cooperative nature of the interaction between a field reservoir and an array of two-level-emitters. The resulting dynamics of the delocalized state can display Rabi-like oscillations when the number of two-level emitters exceeds several hundred. In this case the large array of emitters is essentially behaving like a mirror-less cavity. We outline how this might be realized using a multiple-quantum-well structure and discuss how the quantum nature of these oscillations could be tested with the Leggett-Garg inequality and its extensions.Comment: 29 pages, 5 figures, journal pape

    Fractal Analysis Reveals Reduced Complexity of Retinal Vessels in CADASIL

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    The Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) affects mainly small cerebral arteries and leads to disability and dementia. The relationship between clinical expression of the disease and progression of the microvessel pathology is, however, uncertain as we lack tools for imaging brain vessels in vivo. Ophthalmoscopy is regarded as a window into the cerebral microcirculation. In this study we carried out an ophthalmoscopic examination in subjects with CADASIL. Specifically, we performed fractal analysis of digital retinal photographs. Data are expressed as mean fractal dimension (mean-D), a parameter that reflects complexity of the retinal vessel branching. Ten subjects with genetically confirmed diagnosis of CADASIL and 10 sex and age-matched control subjects were enrolled. Fractal analysis of retinal digital images was performed by means of a computer-based program, and the data expressed as mean-D. Brain MRI lesion volume in FLAIR and T1-weighted images was assessed using MIPAV software. Paired t-test was used to disclose differences in mean-D between CADASIL and control groups. Spearman rank analysis was performed to evaluate potential associations between mean-D values and both disease duration and disease severity, the latter expressed as brain MRI lesion volumes, in the subjects with CADASIL. The results showed that mean-D value of patients (1.42±0.05; mean±SD) was lower than control (1.50±0.04; p = 0.002). Mean-D did not correlate with disease duration nor with MRI lesion volumes of the subjects with CADASIL. The findings suggest that fractal analysis is a sensitive tool to assess changes of retinal vessel branching, likely reflecting early brain microvessel alterations, in CADASIL patients

    Participation, knowledge production, and evaluative research: participation by different actors in a mental health study

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    This article reflects on the interrelations between participation, knowledge production, and public policy evaluation in light of issues from our own experience with evaluative research on a municipal network of Psychosocial Care Centers (CAPS) in Brazil. The article discusses the coordination of the complex process and the potentials and limits of partnerships for conducting qualitative evaluative studies in mental health with participation by different social actors. The authors conclude that qualitative evaluative research aligned with the perspective of including different points of view representing various segments is the best approach for understanding the numerous spin-offs from the implementation of services linked to the Brazilian psychiatric reform movement, given the inherent specificities of the mental health field.No presente texto apresentamos considerações sobre pesquisa avaliativa qualitativa e participativa com base em investigação desta natureza realizada junto a uma rede municipal de Centros de Atenção Psicossocial (CAPS) ligados ao Sistema Único de Saúde (SUS). A coordenação do complexo processo, bem como as potencialidades e limites do estabelecimento de parcerias para a realização de trabalhos de investigação avaliativa qualitativa em saúde mental, com a inclusão de diferentes atores sociais, são aqui discutidas. Concluímos que a pesquisa avaliativa qualitativa aliada à perspectiva de inclusão de distintos pontos de vista dos vários segmentos envolvidos é a que melhor se adequa à compreensão dos muitos desdobramentos oriundos da implementação de serviços ligados ao movimento de reforma psiquiátrica brasileira, dado as especificidades inerentes ao campo da saúde mental.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP)Universidade Estadual de Campinas FCMUNIFESPSciEL

    Self-rated health and factors influencing responses among young Egyptian type 1 diabetes patients

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    <p>Abstract</p> <p>Background</p> <p>Patients diagnosed with type 1 diabetes mellitus (T1DM) face major daily challenges. Self-rated health (SRH) is a global measure of an individual's health related quality of life (HRQoL) and is based on the question, "In general, how would you rate your health?" Subjects rate their health as excellent, very good, good, poor or very poor. Our objective was to determine the HRQoL using the SRH measure and determine factors influencing responses. We hypothesized that better SRH responses were associated with shorter diabetes duration, better compliance and better glycemic control.</p> <p>Methods</p> <p>The standardized SRH measure was the instrument used for health related quality of life assessment. Logistic regression analysis was used to examine the association between SRH responses and selected variables.</p> <p>Results</p> <p>124 subjects, 64 females (51.6%) and 60 males (48.4%) were included. Average age was 13.08 (±3.19) and average diabetes duration was 5.82 (±1.60), while the mean HbA<sub>1</sub>C was 8.02 (±1.60). The majority rated their health as good (31%), 29% rated it as excellent, 11% as very good, 14% as poor and 15% as very poor. Regression analysis showed that regular exercise was the only predictor that was independently and significantly associated with a "better" self-health rating, with an OR of 12.84, CI of 1.425-115.727 and a <it>p </it>value of 0.023.</p> <p>Conclusion</p> <p>Regular exercise among Egyptian children with T1DM is strongly associated with a "better" overall health related quality of life and should be repeatedly encouraged.</p

    Understanding business ecosystem using a 6C framework in Internet-of-Things-based sectors

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    With fast development and application, the Internet of Things (IoT) brings more opportunities to business. This research aims to investigate how IoT could lead to a co-evolving business ecosystem rather than a supply chain. It develops the 6C framework to analyze the data collected from case companies, and identifies three patterns of IoT-based business ecosystem. It also provides a summary of practical implications to guide practitioners building an IoT-based business ecosystem

    Excursions into the Evolution of Early-Type Galaxies in Clusters

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    Recent observations have revealed that early-type galaxies (ETG) in clusters comprise an old galaxy population that is evolving passively. We review some recent observations from the ground and from HST that show that ETG have undergone a significant amount of luminosity evolution. This evolution is traced by two projections of the fundamental plane (FP): the size-magnitude relation (SMR) and the color-magnitude relation (CMR). We will briefly discuss the relevance of all these results in the context of the universality of the IMF.Comment: 10 pages, 2 figures, to appear in the proccedings of "New Quests in Stellar Astrophysics: The Link Between Stars and Cosmology, Chavez et al. ed

    A participatory action research approach to strengthening health managers’ capacity at district level in Eastern Uganda

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    BACKGROUND: Many approaches to improving health managers’ capacity in poor countries, particularly those pursued by external agencies, employ non-participatory approaches and often seek to circumvent (rather than strengthen) weak public management structures. This limits opportunities for strengthening local health managers’ capacity, improving resource utilisation and enhancing service delivery. This study explored the contribution of a participatory action research approach to strengthening health managers’ capacity in Eastern Uganda. METHODS: This was a qualitative study that used open-ended key informant interviews, combined with review of meeting minutes and observations to collect data. Both inductive and deductive thematic analysis was undertaken. The Competing Values Framework of organisational management functions guided the deductive process of analysis and the interpretation of the findings. The framework builds on four earlier models of management and regards them as complementary rather than conflicting, and identifies four managers’ capacities (collaborate, create, compete and control) by categorising them along two axes, one contrasting flexibility versus control and the other internal versus external organisational focus. RESULTS: The findings indicate that the participatory action research approach enhanced health managers’ capacity to collaborate with others, be creative, attain goals and review progress. The enablers included expanded interaction spaces, encouragement of flexibility, empowerment of local managers, and the promotion of reflection and accountability. Tension and conflict across different management functions was apparent; for example, while there was a need to collaborate, maintaining control over processes was also needed. These tensions meant that managers needed to learn to simultaneously draw upon and use different capacities as reflected by the Competing Values Framework in order to maximise their effectiveness. CONCLUSIONS: Improved health manager capacity is essential if sustained improvements in health outcomes in lowincome countries are to be attained. The expansion of interaction spaces, encouragement of flexibility, empowerment of local managers, and the promotion of reflection and accountability were the key means by which participatory action research strengthened health managers’ capacity. The participatory approach to implementation therefore created opportunities to strengthen health managers’ capacity
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