784 research outputs found

    Elementary test for non-classicality based on measurements of position and momentum

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    We generalise a non-classicality test described by Kot et al. [Phys. Rev. Lett. 108, 233601 (2010)], which can be used to rule out any classical description of a physical system. The test is based on measurements of quadrature operators and works by proving a contradiction with the classical description in terms of a probability distribution in phase space. As opposed to the previous work, we generalise the test to include states without rotational symmetry in phase space. Furthermore, we compare the performance of the non-classicality test with classical tomography methods based on the inverse Radon transform, which can also be used to establish the quantum nature of a physical system. In particular, we consider a non-classicality test based on the so-called filtered back-projection formula. We show that the general non-classicality test is conceptually simpler, requires less assumptions on the system and is statistically more reliable than the tests based on the filtered back-projection formula. As a specific example, we derive the optimal test for a quadrature squeezed single photon state and show that the efficiency of the test does not change with the degree of squeezing

    Regulation of the access to genetic resources of natural and historical value and sharing the benefits of their utilisation to favour conservation efforts

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    All living organisms contain or produce structures, genetic material and other chemicals that could be potentially useful to humans in various sectors. In the context of the Convention on Biological Diversity (CBD), these resources are collectively termed genetic resources. Benefits which may be gained from their uses may range from a better understanding of the natural world to the development of a wide range of products and services for human benefit, including medicines, food additives as well as agricultural and environmental practices and techniques.peer-reviewe

    The southernmost beech (Fagus sylvatica) forests of Europe (Mount Etna, Italy): ecology, structural stand-type diversity and management implications

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    The southernmost European beech forests are located in the upper forest vegetation belt on Mount Etna volcano. Their standstructural patterns were analysed to assess the effects of the site-ecological factors and previous management practices on the forest structure. Five main structural-silvicultural types were identified among the main beech forest types: coppice, highmountain coppice (HMCo), high forest, coppice in conversion to high-forest and non-formal stand. A detailed standstructural analysis was carried out through measured dendrometric parameters and derived structural characters linked to both the horizontal and the vertical profiles. Plant regeneration processes were also assessed, and several biodiversity indicators were calculated. The collected data indicate a high variability of beech stand structures in relation to the heterogeneity of the site-ecological characteristics as well as to the effects of both natural and anthropic disturbance factors. The occurrence of particular stand structures along the altitude gradient on Mount Etna is evident. It is especially visible in the multi-stemmed HMCos in relation to the changing, and increasingly limiting, ecological factors, although at higher altitudes historical anthropic actions (felling) also have had an influence. Inside the Mediterranean area, these stands highlight their ecological marginality, in terms of both latitude and altitude, especially regarding current climate change processes

    Más allá de los emisores tradicionales en células electroquímicas emisoras de luz

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    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Aplicada. Fecha de lectura: 09-09-202

    How students perceive medical competences: a cross-cultural study between the Medical Course in Portugal and African Portuguese Speaking Countries

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    <p>Abstract</p> <p>Background</p> <p>A global effort has been made in the last years to establish a set of core competences that define the essential professional competence of a physician. Regardless of the environment, culture or medical education conditions, a set of core competences is required for medical practice worldwide. Evaluation of educational program is always needed to assure the best training for medical students and ultimately best care for patients. The aim of this study was to determine in what extent medical students in Portugal and Portuguese speaking African countries, felt they have acquired the core competences to start their clinical practice. For this reason, it was created a measurement tool to evaluate self-perceived competences, in different domains, across Portuguese and Portuguese-speaking African medical schools.</p> <p>Methods</p> <p>The information was collected through a questionnaire that defines the knowledge, attitudes and skills that future doctors should acquire. The Cronbach's Alpha and Principal Components Analysis (PCA) were used to evaluate the reliability of the questionnaire. In order to remove possible confounding effect, individual scores were standardized by country.</p> <p>Results</p> <p>The order of the domain's scores was similar between countries. After standardization, Personal Attitudes and Professional Behavior showed median scores above the country global median and Knowledge alone showed median score below the country global median. In Portugal, Clinical Skills showed score below the global median. In Angola, Clinical Skills and General Skills showed a similar result. There were only significant differences between countries in Personal Attitudes (p < 0.001) and Professional Behavior (p = 0.043).</p> <p>Conclusions</p> <p>The reliability of the instrument in Portuguese and Portuguese-speaking African medical schools was confirmed. Students have perceived their level of competence in personal attitudes in a high level and in opposite, knowledge and clinical skills with some weaknesses.</p
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