135 research outputs found
Lessons of spin and torsion: Reply to ``Consistent coupling to Dirac fields in teleparallelism"
In reply to the criticism made by Mielke in the pereceding Comment [Phys.
Rev. D69 (2004) 128501] on our recent paper, we once again explicitly
demonstrate the inconsistency of the coupling of a Dirac field to gravitation
in the teleparallel equivalent of general relativity. Moreover, we stress that
the mentioned inconsistency is generic for {\it all} sources with spin and is
by no means restricted to the Dirac field. In this sense the
-covariant generalization of the spinor fields in the teleparallel
gravity theory is irrelevant to the inconsistency problem.Comment: Revtex, 4 pages, no figure
Teleparallel Equivalent of Non-Abelian Kaluza-Klein Theory
Based on the equivalence between a gauge theory for the translation group and
general relativity, a teleparallel version of the non-abelian Kaluza-Klein
theory is constructed. In this theory, only the fiber-space turns out to be
higher-dimensional, spacetime being kept always four-dimensional. The resulting
model is a gauge theory that unifies, in the Kaluza-Klein sense, gravitational
and gauge fields. In contrast to the ordinary Kaluza-Klein models, this theory
defines a natural length-scale for the compact sub-manifold of the fiber space,
which is shown to be of the order of the Planck length.Comment: Revtex4, 7 pages, no figures, to appear in Phys. Rev.
O Cuidado à Saúde Na Perspectiva De Trabalhadores Homens Portadores De Doenças Crônicas
This qualitative study is intended to understand how male, hypertensive and diabetic workers, with low-level education, patients of a primary health care service in Campinas-SP, Brazil, manage their treatment. The results aim to improve the primary health care and the recognition of the special needs of this kind of users. As a result of semi-structured interviews, two categories are reported: one of them is the masculinity-related particularity regarding health care and the other is the experience on caring for chronic disease. Despite the difficulties related to socially constructed male behavior, as work value, reluctance to seek health care, habits like alcoholism and smoking and difficulties with adherence to diet and medication recommendations, there was identified the will and acceptance to treatment. Therefore these findings show the feasibility to promote men’s health care, providing attention to their needs. © 2016, Fundacao UNI Botucatu/UNESP. All rights reserved.205859761
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Environmental evaluation of Surface Mounted Devices (SMD)
We evaluated the comparative reliability of solder interconnections used for Leadless Chip Carriers (LCCs), Meaded, and flat-pack hybrid microcircuits mounted on FR-4 glass epoxy printed wiring boards (PWBs). The board assemblies, with solder attached microcircuits, were repeatedly thermal cycled from - 65 to +125{degrees}C. We recognize that this temperature range far exceeds most testing of assemblies. The purposes of these tests were to evaluate worst-case conditions and to obtain comparative information. Identical PWB assemblies, using these three component types, were subjected to both thermal shock testing (1 cycle every 42 minutes) and temperature cycle testing (1 cycle every 3 hours). The double testing evaluated the differences in stress application and evaluated the potential of replacing slow transition, expensive temperature cycle testing (which has been an industry standard for years) with the much more rapid thermal shock testing
Quality Of Strawberry Grown In Brazilian Tropical Humid Conditions For Breeding Programs
Introduction. The preliminary study of the post-harvest quality of the fruit from strawberry cultivars in a new growing region is necessary for both farmers and consumers. The objective of the present study was to evaluate strawberry cultivars at different harvest times with regard to fruit quality aiming at the selection of possible parents for breeding programs for cultivation in the tropical humid conditions of the city Datas, in Minas Gerais State (Brazil), and in other regions with similar soil-climatic conditions. Materials and methods. The strawberry fields were cultivated on the Mape Frutas Farm, located in the city of Datas-MG. Eight cultivars ('Aromas', 'Camarosa', 'Campinas', 'Diamante', 'Dover', 'Festival', 'Oso Grande', and 'Toyonoka') were assessed in a randomized block design with a split-plot in time. Four replicates and three harvest times (June, August, and October 2012) were evaluated. Fruit from the different cultivars were analyzed for their physicochemical and antioxidant properties. Results and discussion. There was a genetic variability and the predominance of genetic factors over environmental effects for the evaluated traits. Fruits harvested at the end of the crop cycle (October) had the highest levels of total reducing sugars, vitamin C, phenols, anthocyanins, carotenoids, soluble solids, and total antioxidant activity. Cultivars Camarosa, Festival, and Toyonoka showed better fruit quality. Conclusion. Based on the genetic dissimilarity and fruit quality, the cross between 'Toyonoka' and 'Camarosa' or 'Festival' is indicated for the genetic improvement of strawberry in the region and other places with similar soil-climatic conditions. © Cirad/EDP Sciences 2016.71315116
Symmetric Hyperbolic System in the Self-dual Teleparallel Gravity
In order to discuss the well-posed initial value formulation of the
teleparallel gravity and apply it to numerical relativity a symmetric
hyperbolic system in the self-dual teleparallel gravity which is equivalent to
the Ashtekar formulation is posed. This system is different from the ones in
other works by that the reality condition of the spatial metric is included in
the symmetric hyperbolicity and then is no longer an independent condition. In
addition the constraint equations of this system are rather simpler than the
ones in other works.Comment: 8 pages, no figure
Analysis of environmental conditions in two different Compost Bedded Pack Barn systems for dairy cattle
Received: February 1st, 2023 ; Accepted: April 27th, 2023 ; Published: May 10th, 2023 ; Correspondence: [email protected], [email protected] objective of this study was to analyse and compare the thermal environment of
dairy cattle facilities in an open compost bedded pack barn (CBP) with natural ventilation and
closed CBP (without thermal insulation) and climate control system. The research was conducted
in a property located in Zona da Mata, Minas Gerais, Brazil. During the summer and for different
periods of the day, the following average environmental variables observed inside the facilities
were measured: dry bulb temperature, relative humidity and Temperature and Humidity Index
(THI). The results were submitted to an analysis of variance to determine the significance of the
variables in the different treatments. It was found that the closed and climate control system CBP
promoted greater control of the facility's internal microclimate, registering smaller thermal
amplitudes and a greater reduction in the animals' exposure time to stressful thermal conditions,
compared to the CBP with natural ventilation. However, during summer afternoons, comfort
indices indicated moderate stress. It is concluded that the closed CBP, regarding the analysed
variables, indicated potential use, provided that a careful study of the climate of the region is
carried out before implementation, the factors related to the ambient conditioning and better
insulation of the construction are adjusted. The climatic variables inside the open CBP indicated
a high stress condition for the animals, suggesting the placement of positive pressure fans and
sprinklers properly distributed in the feed alley, to guarantee benefits to the entire area of the
animal housing
Conservação Pós-colheita De Frutos De Morangueiro Em Diferentes Condições De Armazenamento
Strawberry is a product appreciated by consumers due to the organoleptic characteristics. However, strawberry fruits are highly perishable after harvest, so alternative measures to prolong the shelf life of fruits are necessary. The objective of this experiment was to evaluate the fruit postharvest conservation of strawberry cultivars under different storage conditions. Strawberry fruits of eight cultivars (Festival, Campinas, Toyonoka, Dover, Oso Grande, Camarosa, Diamante and Aromas) were grown at “Mape Frutas” farm, in Datas municipality, Minas Gerais State, Brazil. Strawberry fruits were stored at cold storage (2.34±0.78°C; 89.93±4.14% RH) and environmental conditions (17.43±2.68°C; 74.11±10.44%). The experimental design was randomized blocks in a factorial arrangement with eight strawberry cultivars and five storage times, with three replications. Fruits appearance, disease incidence, total soluble solids, titratable acidity, vitamin C and firmness were evaluated every 3 days, until 12 days. At room condition, strawberry fruit could be stored for only three days. Fruits kept in cold chamber kept quality until 12 days. Cv. Festival had the best postharvest shelf life in both storage conditions and cvs. Toyonoka and Campinas showed higher incidence of diseases and less fruit firmness when compared to the other cultivars. © 2016, Sociedade de Olericultura do Brasil. All rights reserved.34340541
Quantum Yang-Mills gravity in flat space-time and effective curved space-time for motions of classical objects
Yang-Mills gravity with translational gauge group T(4) in flat space-time
implies a simple self-coupling of gravitons and a truly conserved
energy-momentum tensor. Its consistency with experiments crucially depends on
an interesting property that an `effective Riemannian metric tensor' emerges in
and only in the geometric-optics limit of the photon and particle wave
equations. We obtain Feynman rules for a coupled graviton-fermion system,
including a general graviton propagator with two gauge parameters and the
interaction of ghost particles. The equation of motion of macroscopic objects,
as an N-body system, is demonstrated as the geometric-optics limit of the
fermion wave equation. We discuss a relativistic Hamilton-Jacobi equation with
an `effective Riemann metric tensor' for the classical particles.Comment: 20 pages, to be published in "The European Physical Journal -
Plus"(2011). The final publication is available at http://www.epj.or
Teleparallel Energy-Momentum Distribution of Spatially Homogeneous Rotating Spacetimes
The energy-momentum distribution of spatially homogeneous rotating spacetimes
in the context of teleparallel theory of gravity is investigated. For this
purpose, we use the teleparallel version of Moller prescription. It is found
that the components of energy-momentum density are finite and well-defined but
are different from General Relativity. However, the energy-momentum density
components become the same in both theories under certain assumptions. We also
analyse these quantities for some special solutions of the spatially
homogeneous rotating spacetimes.Comment: 12 pages, accepted for publication in Int. J. Theor. Phy
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