956 resultados para General relativity and gravitation
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The paper addresses five issue areas. First it describes the plurality of trajectories in central and eastern European transformations, offering a broad typology. Then it addresses the drift between acceptance of democracy and the market, owing to growing inequalities. Third, problems of poverty and exclusion are addressed. Fourth, it is addressed if any known model of redistribution emerged in the post-transition economies. Fifth, consequences of the populist turn in European policies are being analyzed. Influences of the EU practices will be dealt with and some preliminary conclusions drawn. These suggest a strong intertwining between social and economic performance that limit theoretically conceivable – neoliberal, social democratic, postmodern or conservative - policy choices.
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This article investigates whether the strength of formal professional relationships between general practitioners (GPs) and specialists (SPs) affects either the health status of patients or their pharmacy costs. To this end, it measures the strength of formal professional relationships between GPs and SPs through the number of shared patients and proxies the patient health status by the number of comorbidities diagnosed and treated. In strong GP–SP relationships, the patient health status is expected to be high, due to efficient care coordination, and the pharmacy costs low, due to effective use of resources. To test these hypotheses and compare the characteristics of the strongest GP–SP connections with those of the weakest, this article concentrates on diabetes—a chronic condition where patient care coordination is likely important. Diabetes generates the largest shared patient cohort in Hungary, with the highest traffic of specialist medication prescriptions. This article finds that stronger ties result in lower pharmacy costs, but not in higher patient health statuses. Key points for decision makers • The number of shared patients may be used to measure the strength of formal professional relationships between general practitioners and specialists. • A large number of shared patients indicates a strong, collaborative tie between general practitioners and specialists, whereas a low number indicates a weak, fragmented tie. • Tie strength does not affect patient health—strong, collaborative ties between general practitioners and specialists do not involve better patient health than weak, fragmented ties. • Tie strength does affect pharmacy costs—strong, collaborative ties between general practitioners and specialists involve significantly lower pharmacy costs than weak, fragmented ties. • Pharmacy costs may be reduced by lowering patient care fragmentation through channelling a general practitioner’s patients to a small number of specialists and increasing collaboration between general practitioner and specialists. • Limited patient choice is financially more beneficial than complete freedom of choice, and no more detrimental to patient health.
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Arra a kérdésre keressük a választ, hogy a szoros háziorvosi-szakorvosi szakmai kapcsolatoknak van-e hatásuk a betegek gyógyszerkiadására, illetve egészségi állapotára. Az orvosok közötti szakmai kapcsolatok szorosságát a közösen gondozott betegek száma alapján határoztuk meg, míg a betegek egészségügyi állapotát a diagnosztizált és kezelt társbetegségek számával mértük. Hipotézisünk egyrészt az volt, hogy a hatékonyabb koordinációnak köszönhetően a szoros kapcsolatban kezelt betegek jobb egészségi állapotúak, másrészt kezelésük az erőforrások hatékonyabb felhasználása miatt kisebb gyógyszerköltséggel jár. E két hipotézist a cukorbetegekre teszteltük. Azért esett erre a krónikus betegségre a választásunk, mert itt a háziorvosok és a szakorvosok együttműködése elsődleges fontosságú. Magyarországon a cukorbetegek esetében a legnagyobb a közösen kezelt betegek populációja, valamint itt a legmagasabb a szakorvosi javaslatra felírt háziorvosi receptek száma. Azt az eredményt kaptuk, hogy a szoros kapcsolatban kezelt betegek nem rendelkeznek sem jobb, sem rosszabb egészségi állapottal, miközben a kapcsolódó gyógyszerkiadásuk szignifikánsan alacsonyabb. ____ The article considers whether strong formal professional relations between GPs and specialists in shared care affect either the health of patients or the pharmacy costs they incur. The strength of such relations is measured by the number of shared patients; patient health is proxied by number of co-morbidities diagnosed and treated. The first hypothesis is that patients treated amid strong GP-specialist relations have better health status than those treated amid weak ones, due to enhanced efficiency of care coordination. The second is that patients treated in such strong relations incur lower pharmacy costs high numbers of shared patients are assumed to promote appropriate, effective use of resources. The article tests these hypotheses and compares the outcomes of the strongest and weakest GP-specialist relations through the example of diabetes, a chronic condition where patient-care coordination is important. Diabetes generates the largest shared patient cohort in Hungary, with the highest number of specialist medication prescriptions. This article finds that stronger ties result in significantly lower pharmacy costs, but not a higher patient health status.
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This study sought to apply the concepts of inquiry-based learning by increasing the number of laboratory experiments conducted in two science classes, and to identify the challenges of this instruction for students with special needs. Results showed that the grades achieved through lab write-ups greatly improved grades overall.
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Financial ratios are the most meaningful information in financial statements to executives and managers. The author analyzes the results of two surveys designed to rank the degree of importance and usefulness of these ratios to several user groups.
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Objective: This qualitative study set in the West Midlands region of the United Kingdom, aimed to examine the role of the general practitioner (GP) in children's oncology palliative care from the perspective of GPs who had cared for a child with cancer receiving palliative care at home and bereaved parents. Methods: One-to-one semi-structured interviews were undertaken with 18 GPs and 11 bereaved parents following the death. A grounded theory data analysis was undertaken; identifying generated themes through chronological comparative data analysis. Results: Similarity in GP and parent viewpoints was found, the GPs role seen as one of providing medication and support. Time pressures GPs faced influenced their level of engagement with the family during palliative and bereavement care and their ability to address their identified learning deficits. Lack of familiarity with the family, coupled with an acknowledgment that it was a rare and could be a frightening experience, also influenced their level of interaction. There was no consistency in GP practice nor evidence of practice being guided by local or national policies. Parents lack of clarity of their GPs role resulted in missed opportunities for support. Conclusions: Time pressures influence GP working practices. Enhanced communication and collaboration between the GP and regional childhood cancer centre may help address identified GP challenges, such as learning deficits, and promote more time-efficient working practices through role clarity. Parents need greater awareness of their GP's wide-ranging role; one that transcends palliative care incorporating bereavement support and on-going medical care for family members
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Using our anholonomic frame deformation method, we show how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates and undergoing a phase of ultra-slow contraction can be constructed in massive gravity. In this paper, there are found and studied new classes of locally anisotropic and (in)homogeneous cosmological metrics with open and closed spatial geometries. The late time acceleration is present due to effective cosmological terms induced by nonlinear off-diagonal interactions and graviton mass. The off-diagonal cosmological metrics and related Stückelberg fields are constructed in explicit form up to nonholonomic frame transforms of the Friedmann–Lamaître–Robertson–Walker (FLRW) coordinates. We show that the solutions include matter, graviton mass and other effective sources modeling nonlinear gravitational and matter fields interactions in modified and/or massive gravity, with polarization of physical constants and deformations of metrics, which may explain certain dark energy and dark matter effects. There are stated and analyzed the conditions when such configurations mimic interesting solutions in general relativity and modifications and recast the general Painlevé–Gullstrand and FLRW metrics. Finally, we elaborate on a reconstruction procedure for a subclass of off-diagonal cosmological solutions which describe cyclic and ekpyrotic universes, with an emphasis on open issues and observable signatures.
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Background and aims: The prevalence of anti-HCV and HBsAg in Portugal has been shown to be elevated in high-risk groups, such as intravenous drug-users and incarcerated individuals. However, in the general population, prevalence remains largely unknown. The aims of this study were to estimate the prevalence of anti-HCV and HBsAg in the general Portuguese population and identify associated risk factors. Materials and methods: We carried out a nationwide, population-based cross-sectional study of adults resident in mainland Portugal. Serology for HBsAg, anti-HBc, anti-HBs, and anti-HCV was performed. Anti-HCV-positive individuals were tested for HCV RNA by PCR. Results: Of 1685 participants, 50.6% were men, mean age 50.2±18.3 years. In terms of hepatitis C, the prevalence of anti-HCV was 0.54% [95% confidence interval (CI): 0.2–0.9] and 0.12% (95% CI: 0.0–0.3) were viremic, with peak prevalence among individuals 35–64 years of age (0.8%), men (0.8%), and individuals from Lisbon and Tagus Valley region (1.9%). In terms of hepatitis B, the estimated prevalence of HBsAg was 1.45% (95% CI: 0.9–2.0). A higher prevalence was found in individuals who were 35–64 years old (2.2%), in men (2.5%), and in the Northern region (2.6%). The presence of positive serological markers of hepatitis C virus and hepatitis B virus infection did not correlate with elevated aminotransferases, race, place of birth, and alcohol consumption. Conclusion: These results suggest a low endemicity for both hepatitis B and hepatitis C in the general population, in contrast to a very high prevalence in risk groups, thus suggesting that targeted screening to high-risk groups may be more cost-effective than general population screening.
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This document describes the general principles of Digital Object Identifiers (DOI). It provide examples of DOI implementation useful for AtlantOS H2020 project networks. A DOI is an allocation of unique identifier. Generally used to identify scientific publications, a DOI can be attributed to any physical, numerical or abstract resource.
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This study evaluated whether psychache (i.e., mental pain) mediates the association between general distress, assessed as the frequency and the intensity of psychological symptoms in the previous week, and suicide ideation in community adults. For a sample of 202 adults, psychache fully mediated the relationship between suicide ideation and the frequency of psychological symptoms, and partially mediated the relationship between suicide ideation and the intensity of psychological symptoms. As such, mental pain fully or partially explains the process linking the frequency and the intensity of general distress to suicide ideation and, thus, mental pain is a target for potential intervention.
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Planning is an important sub-field of artificial intelligence (AI) focusing on letting intelligent agents deliberate on the most adequate course of action to attain their goals. Thanks to the recent boost in the number of critical domains and systems which exploit planning for their internal procedures, there is an increasing need for planning systems to become more transparent and trustworthy. Along this line, planning systems are now required to produce not only plans but also explanations about those plans, or the way they were attained. To address this issue, a new research area is emerging in the AI panorama: eXplainable AI (XAI), within which explainable planning (XAIP) is a pivotal sub-field. As a recent domain, XAIP is far from mature. No consensus has been reached in the literature about what explanations are, how they should be computed, and what they should explain in the first place. Furthermore, existing contributions are mostly theoretical, and software implementations are rarely more than preliminary. To overcome such issues, in this thesis we design an explainable planning framework bridging the gap between theoretical contributions from literature and software implementations. More precisely, taking inspiration from the state of the art, we develop a formal model for XAIP, and the software tool enabling its practical exploitation. Accordingly, the contribution of this thesis is four-folded. First, we review the state of the art of XAIP, supplying an outline of its most significant contributions from the literature. We then generalise the aforementioned contributions into a unified model for XAIP, aimed at supporting model-based contrastive explanations. Next, we design and implement an algorithm-agnostic library for XAIP based on our model. Finally, we validate our library from a technological perspective, via an extensive testing suite. Furthermore, we assess its performance and usability through a set of benchmarks and end-to-end examples.
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El nostre objectiu es l'estudi d'extensions de la Relativitat General i, en particular, estem interessats en les teories que continguin camps vectorials addicionals. En aquests tipus de teories es necessari imposar que el vector ha de tenir norma fixa per evitar la presència d'un fantasma o grau de llibertat amb terme cinètic negatiu, i això implica que la simetria Lorentz està trencada espontàniament. El camp del aether només interactua gravitatòriament i la seva presència es difícil de detectar, no obstant això, durant inflació les fluctuacions del buit a escales petites d'un camp lleuger pot deixar una empremta en observables com les anisotropies del fons de radiació de microones. Les fluctuacions del Einstein-aether es comporten com els camps sense massa i això fa que inflació generi modes de longitud de ona llarga en els sectors escalar i vectorial. Hem estudiat la signatura del Einstein-aether dins l'espectre de pertorbacions primordials lluny del límit de de Sitter de inflació. Aquests modes escalars i vectorials poden deixar una empremta significativa en la radiació de fons de microones en funció dels paràmetres del model. Les observacions del fons de radiació de microones imposen restriccions fenomenològiques que redueixen els límits existents per aquesta classe de teoria. Amb aquest estudi del aether també esperem millorar el coneixement que tenim de una classe més ampla de teories que exhibeixen el mateix tipus de trencament de simetria.
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The dissertation investigates some relevant metaphysical issues arising in the context of spacetime theories. In particular, the inquiry focuses on general relativity and canonical quantum gravity. A formal definition of spacetime theory is proposed and, against this framework, an analysis of the notions of general covariance, symmetry and background independence is performed. It is argued that many conceptual issues in general relativity and canonical quantum gravity derive from putting excessive emphasis on general covariance as an ontological prin-ciple. An original metaphysical position grounded in scientific essential- ism and causal realism (weak essentialism) is developed and defended. It is argued that, in the context of general relativity, weak essentialism supports spacetime substantivalism. It is also shown that weak essentialism escapes arguments from metaphysical underdetermination by positing a particular kind of causation, dubbed geometric. The proposed interpretive framework is then applied to Bohmian mechanics, pointing out that weak essentialism nicely fits into this theory. In the end, a possible Bohmian implementation of loop quantum gravity is considered, and such a Bohmian approach is interpreted in a geometric causal fashion. Under this interpretation, Bohmian loop quantum gravity straightforwardly commits us to an ontology of elementary extensions of space whose evolution is described by a non-local law. The causal mechanism underlying this evolution clarifies many conceptual issues related to the emergence of classical spacetime from the quantum regime. Although there is as yet no fully worked out physical theory of quantum gravity, it is argued that the proposed approach sets up a standard that proposals for a serious ontology in this field should meet.
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We derive the back reaction on the gravitational field of a straight cosmic string during its formation due to the gravitational coupling of the string to quantum matter fields. A very simple model of string formation is considered. The gravitational field of the string is computed in the linear approximation. The vacuum expectation value of the stress tensor of a massless scalar quantum field coupled to the string gravitational field is computed to one loop order. Finally, the back-reaction effect is obtained by solving perturbatively the semiclassical Einsteins equations.