1,281 research outputs found

    Construction of the B88 exchange-energy functional in two dimensions

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    We construct a generalized-gradient approximation for the exchange-energy density of finite two-dimensional systems. Guided by non-empirical principles, we include the proper small-gradient limit and the proper tail for the exchange-hole potential. The observed performance is superior to that of the two-dimensional local-density approximation, which underlines the usefulness of the approach in practical applications

    Light-cone averaging in cosmology: formalism and applications

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    We present a general gauge invariant formalism for defining cosmological averages that are relevant for observations based on light-like signals. Such averages involve either null hypersurfaces corresponding to a family of past light-cones or compact surfaces given by their intersection with timelike hypersurfaces. Generalized Buchert-Ehlers commutation rules for derivatives of these light-cone averages are given. After introducing some adapted "geodesic light-cone" coordinates, we give explicit expressions for averaging the redshift to luminosity-distance relation and the so-called "redshift drift" in a generic inhomogeneous Universe.Comment: 20 pages, 2 figures. Comments and references added, typos corrected. Version accepted for publication in JCA

    Entropic force and its cosmological implications

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    We investigate a possibility of realizing the entropic force into the cosmology. A main issue is how the holographic screen is implemented in the Newtonian cosmology. Contrary to the relativistic realization of Friedmann equations, we do not clarify the connection between Newtonian cosmology and entropic force because there is no way of implementing the holographic screen in the Newtonian cosmology.Comment: 16 pages, no figures, version "Accepted for publication in Astrophysics & Space Science

    Casimir effect between moving branes

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    We consider a supersymmetric model with a single matter supermultiplet in a five-dimensional space-time with orbifold compactification along the fifth dimension. The boundary conditions on the two orbifold planes are chosen in such a way that supersymmetry remains unbroken on the boundaries. We calculate the vacuum energy-momentum tensor in a configuration in which the boundary branes are moving with constant velocity. The results show that the contribution from fermions cancels that of bosons only in the static limit, but in general a velocity-dependent Casimir energy arises between the branes. We relate this effect to the particle production due to the branes motion and finally we discuss some cosmological consequences.Comment: 14 pages, LaTeX. Final version with new references included, to be published in Nucl. Phys.

    Concealment of type 1 diabetes at work in Finland: a mixed-method study

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    Objectives To explore the possible reasons for concealing type 1 diabetes (T1D) at work. Methods The main set of data came from a cross-sectional survey (response rate 49.3%), the participants of which were 688 wage earners with T1D. Concealment of T1D was measured by asking respondents have they ever during their working career hidden their diabetes from their (A) colleagues and (B) line manager. Furthermore, semistructured interviews (n=20) were conducted to obtain deeper understanding. Questionnaire data were analysed using logistic regression analyses and qualitative interviews with inductive thematic analysis. Results About 30% of wage earners with T1D had concealed their condition during their working career from their colleagues and almost 20% from their line manager. Individuals aged 18–44 years age were more likely to conceal their T1D from their colleagues than older workers during their working career. Not disclosing T1D to the extended family (OR 5.24 (95% CI 2.06 to 13.35)), feeling an outsider at work (OR 2.47 (95% CI 1.58 to 3.84)), being embarrassed by receiving special attention at work (OR 1.99 (95% CI 1.33 to 2.96)) and neglecting treatment at work (OR 1.59 (95% CI 1.01 to 2.48)) were all associated with concealment of T1D from colleagues. The youngest age group of 18–24 years were more likely to conceal their T1D from their line managers than the older age groups during their working career. Not disclosing T1D to the extended family (OR 4.41 (95% CI 1.72 to 11.32)), feeling like an outsider at work (OR 2.51 (1.52 to 4.14)) and being embarrassed by receiving special attention at work (OR 1.81 (95% CI 1.13 to 2.91)) were associated with concealment of T1D from line managers. From the interviews, five main themes related to concealment emerged, expressing fears related to the consequences of telling: (1) being perceived as weak, (2) job discrimination, (3) unwanted attention, (4) being seen as a person who uses their T1D for seeking advantages and (5) losing privacy. Conclusions A considerable proportion of wage earners with T1D are concealing their diagnosis often because of feelings associated with stigma. Both overemphasis and underestimation of T1D at work by the colleagues or line manager may lead to concealing T1D and may thus be harmful to self-management of T1D. The obstacles in disclosing T1D might be diminished by giving adequate information at the workplace about the condition and its significance

    Light propagation in statistically homogeneous and isotropic universes with general matter content

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    We derive the relationship of the redshift and the angular diameter distance to the average expansion rate for universes which are statistically homogeneous and isotropic and where the distribution evolves slowly, but which have otherwise arbitrary geometry and matter content. The relevant average expansion rate is selected by the observable redshift and the assumed symmetry properties of the spacetime. We show why light deflection and shear remain small. We write down the evolution equations for the average expansion rate and discuss the validity of the dust approximation.Comment: 42 pages, no figures. v2: Corrected one detail about the angular diameter distance and two typos. No change in result

    Disclosure of type 1 diabetes at work among Finnish workers

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    © 2016 Diabetes UK.Aims: To determine which self-management factors and psychosocial work factors were associated with disclosing diabetes to colleagues, line managers and occupational health personnel among workers with Type 1 diabetes. Methods: A total of 767 working-aged respondents with Type 1 diabetes completed a Finnish cross-sectional survey named 'People with Type 1 Diabetes in Worklife'. Factor analysis was carried out, followed by logistic regressions to estimate the associations between self-management factors, psychosocial work factors and the likelihood of disclosure separately to colleagues, line managers and occupational health personnel. The models were adjusted for sociodemographic, diabetes-related and work-related variables. Results: A total of 52% of the respondents had disclosed their diabetes to their colleagues, 45% to occupational health personnel and 28% to their line manager. Receiving social support and having good psychosocial work ability were significantly associated with disclosure to colleagues, line managers and occupational health personnel. Relations at work were associated with disclosure to colleagues and the line manager. Furthermore, opportunity to self-manage diabetes at work was associated with disclosure to colleagues. Conclusions: Line managers and colleagues have a remarkable role to play in providing workplace support to workers with Type 1 diabetes. Disclosure of Type 1 diabetes should be encouraged as line managers can provide workers with the right support, implement work adaptations and facilitate job retention. As only half of respondents disclosed their Type 1 diabetes at work, further research is required into the reasons for and consequences of not disclosing a diagnosis

    Disintegrin and metalloproteinases (ADAMs) expression in gastroesophageal reflux disease and in esophageal adenocarcinoma

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    Clinically useful marker molecules for the progression of gastroesophageal reflux disease and Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) are lacking. Many adenocarcinomas and inflammatory conditions exhibit increased expression of ADAMs, 'a disintegrin and metalloproteinases'. We assessed the expression of five ADAMs (9, 10, 12, 17, 19) in three esophageal cell lines (Het-1A, OE19, OE33) by RT-PCR and Western blotting, and in human samples of normal esophagus, esophagitis, BE, Barrett's dysplasia, and EAC by RT-PCR, and in selected samples by immunohistochemistry. EAC patients showed increased mRNA expression of ADAMs 9, 12, 17 and 19, as compared to controls. At immunohistochemistry, ADAM9 and ADAM10 proteins were increased in EAC. Patient samples also showed increased mRNA expression of ADAM12 in esophagitis, of ADAM9 in BE, and of ADAMs 9, 12 and 19 in Barrett's dysplasia, as compared to controls. Two EAC cell lines showed increased ADAM9 mRNA. ADAM9 expression is increased in EAC. Its predecessors show increased ADAM9 mRNA expression. The importance of the alterations in ADAM expression for the development of EAC, and their use as marker molecules, warrant further studies.Peer reviewe

    Chameleonic dilaton, nonequivalent frames, and the cosmological constant problem in quantum string theory

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    The chameleonic behaviour of the String theory dilaton is suggested. Some of the possible consequences of the chameleonic string dilaton are analyzed in detail. In particular, (1) we suggest a new stringy solution to the cosmological constant problem and (2) we point out the non-equivalence of different conformal frames at the quantum level. In order to obtain these results, we start taking into account the (strong coupling) string loop expansion in the string frame (S-frame), therefore the so-called form factors are present in the effective action. The correct Dark Energy scale is recovered in the Einstein frame (E-frame) without unnatural fine-tunings and this result is robust against all quantum corrections, granted that we assume a proper structure of the S-frame form factors in the strong coupling regime. At this stage, the possibility still exists that a certain amount of fine-tuning may be required to satisfy some phenomenological constraints. Moreover in the E-frame, in our proposal, all the interactions are switched off on cosmological length scales (i.e. the theory is IR-free), while higher derivative gravitational terms might be present locally (on short distances) and it remains to be seen whether these facts clash with phenomenology. A detailed phenomenological analysis is definitely necessary to clarify these points
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