9 research outputs found

    Casimir effect for scalar fields with Robin boundary conditions in Schwarzschild background

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    The stress tensor of a massless scalar field satisfying Robin boundary conditions on two one-dimensional wall in two-dimensional Schwarzschild background is calculated. We show that vacuum expectation value of stress tensor can be obtained explicitly by Casimir effect, trace anomaly and Hawking radiation.Comment: 10 pages, no figure

    Trace anomaly and Casimir effect

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    The Casimir energy for scalar field of two parallel conductor in two dimensional domain wall background, with Dirichlet boundary conditions, is calculated by making use of general properties of renormalized stress tensor.We show that vacuum expectation values of stress tensor contain two terms which come from the boundary conditions and the gravitational background. In two dimensions the minimal coupling reduces to the conformal coupling and stress tensor can be obtained by the local and non-local contribution of the anomalous trace. This work shows that there exists a subtle relation between Casimir effect and trace anomaly in curved space time.Comment: 6pages, Latex. Journal-ref adde

    Analogue Gravity

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    The evaluation and presentation of a rare case of gonadal dysgenesis

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    A seventeen-years old woman was presented with infertility and primary amenorrhea. She had normal stature, femate phenotype and normal development of breasts, external genitalia, vagina and cervix. Pelvic examination showed a large lobulated mass. On sonography there was a mass with probable origin of ovary. Paraclinic tests were carried out. Gonadotropins were in postmeno pausal limits. Alpha Fetoprotein, Beta Subunit (B-HCG) assay were normal Laparotomy revealed a gonadat mass on right side, normal uterus and left streak gonad. Pathologic report of tumor was dysgerminoma and teratoma. Due to pathology of tumor and Y chromosome, we advised the patient to remove the other streak gonad and have irradiati

    Two surgical vaginoplasty methods: A comparative study in Vali-e-asr Hospital

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    Background: To evaluate long-term outcome and satisfaction of MacIndo surgery with and without amnion graft. Methods: This is a historical cohort study of patients who were treated with the McIndo procedure for vaginal agenesis. Participants answered a structured questionnaire to describe outcome in sexual function and satisfaction. Patient characteristics along with short and long-term endings were abstracted from the medical records. Results: Thirty-five patients responded to the questionnaire. Average age (±SD) at surgery was 28.4 ± 3 years (range 17- 48 years). The mean number of years (±SD) since surgery was 7 years (range 2-12 years). In 15 patients (42.8%) amniotic graft were amniotic graft were used only in is patients (42.8%). There was no relation between two types of surgery (long-term outcome and satisfaction with p-values of 0.346 and 0.758 respectively). Conclusions: Since there was not a statistical difference between these two types of McIndo methods, it is recommended to apply the procedure in which amnion is not used. This procedure (without amnion graft), is an easier method with less operation time and reduced viral (HIV…) transmission

    Meconium-Stained Amniotic Fluid as an Independent Risk Factor for Fever and Postpartum Infection in Term Pregnancy

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    Background: The aim of this study was to statistically evaluate the hypothesis that the presence of meconium-stained amniotic fluid is associated with postpartum maternal infection.Methods: This prospective cohort study included 573 term pregnant women in labor, with no other medical problems, that underwent cesarean section for pregnancy termination. Women with prolonged active-phase labor, prolonged rupture of membranes, complicated cesarean section and pre-operative infections were excluded from this study.The subjects were divided into two groups: 280 women with meconium-stained amniotic fluid (M group), and 293 women with clear amniotic fluid (C group). A comparison was done regarding postpartum fever, endometritis and wound infection between the two groups. Students t-test and chi square test were used for data analysis, along with linear regression, with p<0.05 indicating significance.Results: Among the 573 women, a total of 82 women (14%) had fever after cesarean; 42 women from the M group, and 40 women from the C group (p= 0.3). Among the 82 women who had fever, 33 women had continuous fever, 6.5% in group M and 2.7% in group C (p<0.05, RR: 1.98, 95% CI 1.3-3.1). Among the 573 women, 4% developed endometritis 5% in group M and 2% in group C (p<0.05, RR: 2.3, 95%, CI 1.3-3.4). Similarly, among the 573 women, a total of 5 women (1%) developed wound infection, 1.7% in group M and 0.68% in group C (p=0.7).Conclusion: Meconium-stained amniotic fluid is associated with increased postpartum infection independent of other risk factors for infection

    Analogue Gravity

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    Analogue models of (and for) gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing) and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity)
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