127 research outputs found
Weyl-Cartan-Weitzenb\"{o}ck gravity as a generalization of teleparallel gravity
We consider a gravitational model in a Weyl-Cartan space-time, in which the
Weitzenb\"{o}ck condition of the vanishing of the sum of the curvature and
torsion scalar is also imposed. Moreover, a kinetic term for the torsion is
also included in the gravitational action. The field equations of the model are
obtained from a Hilbert-Einstein type variational principle, and they lead to a
complete description of the gravitational field in terms of two fields, the
Weyl vector and the torsion, respectively, defined in a curved background. The
cosmological applications of the model are investigated for a particular choice
of the free parameters in which the torsion vector is proportional to the Weyl
vector. Depending on the numerical values of the parameters of the cosmological
model, a large variety of dynamic evolutions can be obtained, ranging from
inflationary/accelerated expansions to non-inflationary behaviors. In
particular we show that a de Sitter type late time evolution can be naturally
obtained from the field equations of the model. Therefore the present model
leads to the possibility of a purely geometrical description of the dark
energy, in which the late time acceleration of the Universe is determined by
the intrinsic geometry of the space-time.Comment: 15 pages, 5 figures; title changed, major modifications; accepted for
publication in JCA
The effect of olive oil and the Saj (R) cream in prevention of striae gravidarum: A randomized controlled clinical trial
Objective: To compare the clinical efficacy of olive oil and the Saj (R) cream on the occurrence and severity of striae gravidarum. Design: Parallel randomized controlled clinical trial. Setting: West Health Centre, Lolagar and Akbarabadi Hospitals, Tehran, Iran. Interventions: 360 Nulliparous women at their second trimester of pregnancy randomly (simple randomization) allocated into three groups of olive oil, the Saj cream, and control that finally 150 of them (50 subjects in each group) completed the study. Control group did not receive any medication/intervention. At gestational age of 38-40 weeks the participants were evaluated regarding the occurrence of striae on abdominal skin and its severity that were primary outcome of the study. Results: In the olive oil group, striae occurred in 72% of the participants, which were mild, moderate, and severe in 32%, 26%, and 6% of the cases, respectively. In those who received Saj cream, striae occurred in 64% of the cases, which were mild, moderate and severe in 16%, 34%, and 14% of the cases, respectively. With regard to the control group, striae occurred in 60% of the participants, among which striae were mild, moderate, and severe in 22%, 24%, and 14% of the cases, respectively. There were no statistically significant differences among the three studied groups regarding the incidence or severity of striae. Conclusion: Neither olive oil nor the Saj cream were effective in preventing the occurrence of striae gravidarum or affecting its severity. Further studies to examine the effect of other herbal/chemical preparations on occurrence of striae gravidarum are recommended. (C) 2013 Elsevier Ltd. All rights reserved
The effect of olive oil on prevention of striae gravidarum: A randomized controlled clinical trial
Objectives: Striae gravidarum (SG) is one of the cutaneous physiological changes during pregnancy with a high prevalence. This study aimed to evaluate the effect of olive oil in prevention of SG. Design: Randomized controlled clinical trial. Setting: Health care centers and three Hospitals affiliated to Tehran University of Medical Sciences. Participants: 100 nulliparous pregnant women. Interventions: Fifty women were randomly allocated to each study group. The treatment group received 1 cc topical olive oil twice a day to apply on the abdominal skin in a gentle manner without massaging it until the delivery. Control group did not receive any cream or oil during the study. Main outcome measures: Development of SG and its severity was recorded at the end of the study. Results: Although the frequency of severe SG was lower in the users of olive oil compared to the other group, no statistically significant difference was found between the two experimental groups and the control group in the incidence and the severity of SG. Conclusion: Olive oil reduces the incidence of severe SG and increases the incidence of mild SG, but it does not significantly reduce the incidence and the severity of SG and it could not be recommended for SG prevention. (C) 2012 Elsevier Ltd. All rights reserved
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