4,200 research outputs found
Consistent Gravitationally-Coupled Spin-2 Field Theory
Inspired by the translational gauge structure of teleparallel gravity, the
theory for a fundamental massless spin-2 field is constructed. Accordingly,
instead of being represented by a symmetric second-rank tensor, the fundamental
spin-2 field is assumed to be represented by a spacetime (world) vector field
assuming values in the Lie algebra of the translation group. The flat-space
theory naturally emerges in the Fierz formalism and is found to be equivalent
to the usual metric-based theory. However, the gravitationally coupled theory,
with gravitation itself described by teleparallel gravity, is shown not to
present the consistency problems of the spin-2 theory constructed on the basis
of general relativity.Comment: 16 pages, no figures. V2: Presentation changes, including addition of
a new sub-section, aiming at clarifying the text; version accepted for
publication in Class. Quantum Grav
Molecular properties via a subsystem density functional theory formulation: A common framework for electronic embedding
In this article, we present a consistent derivation of a density functional theory (DFT) based embedding method which encompasses wave-function theory-in-DFT (WFT-in-DFT) and the DFT-based subsystem formulation of response theory (DFT-in-DFT) by Neugebauer [J. Neugebauer, J. Chem. Phys. 131, 084104 (2009)10.1063/1.3212883] as special cases. This formulation, which is based on the time-averaged quasi-energy formalism, makes use of the variation Lagrangian techniques to allow the use of non-variational (in particular: coupled cluster) wave-function-based methods. We show how, in the time-independent limit, we naturally obtain expressions for the ground-state DFT-in-DFT and WFT-in-DFT embedding via a local potential. We furthermore provide working equations for the special case in which coupled cluster theory is used to obtain the density and excitation energies of the active subsystem. A sample application is given to demonstrate the method. © 2012 American Institute of Physics
Hodge Dual for Soldered Bundles
In order to account for all possible contractions allowed by the presence of
the solder form, a generalized Hodge dual is defined for the case of soldered
bundles. Although for curvature the generalized dual coincides with the usual
one, for torsion it gives a completely new dual definition. Starting from the
standard form of a gauge lagrangian for the translation group, the generalized
Hodge dual yields precisely the lagrangian of the teleparallel equivalent of
general relativity, and consequently also the Einstein-Hilbert lagrangian of
general relativity.Comment: 8 pages, no figures. Accepted for publication in Journal of Physics
Severidade da queima das folhas e quantificação de fenóis solúveis totais e lagnina solúveil em cultivares de cenoura.
O objetivo deste trabalho foi avaliar a severidade da doença em cultivares tradicionais de cenoura (BrasĂlia, BRS Planalto, Juliana, BRS Esplanada, Branca Lunar, Amarela Solar e Londrina) em campo, bem com quantificar as concentrações de fenĂłis solĂşveis totais e lignina solĂşvel nas folhas.Resumo 1265
Citronella essential oil in the control and activation of coffee plants defense response against rust and brown eye spot.
Objetivou-se avaliar o óleo essencial de citronela no controle da ferrugem e cercosporiose e na ativação de respostas de defesa em cafeeiro
A Study on Binary Asteriod System Deflection
The study of asteroids, its composition and trajectories, has been a
persistent interest in the space exploration community. In addition, they are
also perceived as a great threat to life on Earth, considering the possibility
of an impact with our planet. A considerable portion, around 15%, of the
asteroid population are believed to be part of a double or triple asteroid
system
A healthy dietary pattern associates with a lower risk of a first clinical diagnosis of central nervous system demyelination
Background: The evidence associating diet and risk of multiple sclerosis is inconclusive. Objective: We investigated associations between dietary patterns and risk of a first clinical diagnosis of central nervous system demyelination, a common precursor to multiple sclerosis. Methods: We used data from the 2003–2006 Ausimmune Study, a case–control study examining environmental risk factors for a first clinical diagnosis of central nervous system demyelination, with participants matched on age, sex and study region. Using data from a food frequency questionnaire, dietary patterns were identified using principal component analysis. Conditional logistic regression models (n = 698, 252 cases, 446 controls) were adjusted for history of infectious mononucleosis, serum 25-hydroxyvitamin D concentrations, smoking, race, education, body mass index and dietary misreporting. Results: We identified two major dietary patterns – healthy (high in poultry, fish, eggs, vegetables, legumes) and Western (high in meat, full-fat dairy; low in wholegrains, nuts, fresh fruit, low-fat dairy), explaining 9.3% and 7.5% of variability in diet, respectively. A one-standard deviation increase in the healthy pattern score was associated with a 25% reduced risk of a first clinical diagnosis of central nervous system demyelination (adjusted odds ratio 0.75; 95% confidence interval 0.60, 0.94; p = 0.011). There was no statistically significant association between the Western dietary pattern and risk of a first clinical diagnosis of central nervous system demyelination. Conclusion: Following healthy eating guidelines may be beneficial for those at high risk of multiple sclerosis
Oral and maxillofacial lesions in older individuals and associated factors : a retrospective analysis of cases retrieved in two different services
Studies on the oral and maxillofacial lesions (OMLs) in older people usually assess data of laboratory services and data from oral medicine clinic have been poorly described. The aim of this study was to describe and to compare OMLs in older individuals considering two data sources, besides to assess associated factors with the three most frequent lesions. A retrospective study was conducted with individuals aged 60 years or older. Data of individuals and lesions reported in both services were collected. Univariate analysis was used to test the association between the occurrence of the lesion and the independent variables. The level of significance was set at 5%. A total of 1,695 (37.3%) records were from the Oral Medicine clinic and 2,848 (62.7%) from the Laboratory service. Inflammatory/reactive lesion group was the most frequent in both services (40.4% in Oral Medicine Clinic and in 44.2% Laboratory). The second and third groups of lesions in the Oral Medicine clinic were infectious diseases (18.5%), and variations of normality (10.8%), while in the laboratorial service were the malignant neoplasms (17.6%) and potentially malignant disorders (13.3%). Differences between services regarding the frequency of lesion groups occurred (p<0.05), except for pigmented (p=0.054) and infectious (p=0.054) groups. Females (OR: 2.08; CI: 1.81?2.39) and individuals who wore a removable prosthesis (OR: 3.99; CI: 2.83?5.62) were also likely to have inflammatory fibrous hyperplasia. Old?old individuals (OR: 1.70; CI: 1.30?2.21), male (OR: 3.63; CI: 3.00?4.39), smoking (OR: 6.05; CI: 4.84?7.56) or alcohol use (OR: 3.95; CI: 3.12?5.01) were likely to have squamous cell carcinoma. The results showed different frequencies of OMLs in older individuals according to the data sources and age group. The findings are important to direct public policies for this age group
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