Analytical calculation of the solid angle subtended by a circular disc detector at a point cosine source

We derive analytical expressions for the solid angle subtended by a circular disc at a point source with cosine angular distribution ($f(\mu)=\mu/\pi$)under the sole condition that the disc lies in the half-space illuminated by the source ($\mu \geq 0$). The expressions are given with reference to two alternative coordinate systems (S and S'), S being such that the z axis is parallel to the symmetry axis of the disc and S' such that the $z'$ axis is aligned with the source direction. Sample plots of the expressions are presented.Comment: 12 pages, 10 figures, LaTex12 pages, 10 figures, LaTex. Minor changes from previous version: references added, english reshaping, the phrase "If beta=0.." (pag. 5 near eq. 20 in the old version) was corrected to "If beta=pi/2..

Analytical calculation of the solid angle defined by a cylindrical detector and a point cosine source with orthogonal axes

We derive analytical expressions for the solid angle subtended by a right circular cylinder at a point source with cosine angular distribution in the case where the source and the cylinder axes are mutually orthogonal.Comment: 19 pages, 13 figures, Latex. Typos corrected. Accepted in Rad. Phys. Che

Solid angle subtended by a cylindrical detector at a point source in terms of elliptic integrals

The solid angle subtended by a right circular cylinder at a point source located at an arbitrary position generally consists of a sum of two terms: that defined by the cylindrical surface ($\Omega_{cyl}$) and the other by either of the end circles ($\Omega_{circ}$). We derive an expression for $\Omega_{cyl}$ in terms of elliptic integrals of the first and third kinds and give similar expressions for $\Omega_{circ}$ using integrals of the first and second kinds. These latter can be used alternatively to an expression also in terms of elliptic integrals, due to Philip A. Macklin and included as a footnote in Masket (Rev. Sci. Instr., 28 (3), 191-197, 1957). The solid angle subtended by the whole cylinder when the source is located at an arbitrary location can then be calculated using elliptic integrals.Comment: 10 pages, 3 figures, LaTex. Typos corrected. References added. Accepted in Rad. Phys. Che

Efficacy of misoprostol for the treatment of postpartum hemorrhage: current knowledge and implications for health care planning.

BackgroundA myriad of interventions exist to treat postpartum hemorrhage (PPH), ranging from uterotonics and hemostatics to surgical and aortic compression devices. Nonetheless, PPH remains the leading cause of maternal mortality worldwide. The purpose of this article is to review the available evidence on the efficacy of misoprostol for the treatment of primary PPH and discuss implications for health care planning.Data and methodsUsing PubMed, Web of Science, and GoogleScholar, we reviewed the literature on randomized controlled trials of interventions to treat PPH with misoprostol and non-randomized field trials with controls. We discuss the current knowledge and implications for health care planning, especially in resource-poor settings.ResultsThe treatment of PPH with 800 μg of misoprostol is equivalent to 40 IU of intravenous oxytocin in women who have received oxytocin for the prevention of PPH. The same dose might be an option for the treatment of PPH in women who did not receive oxytocin for the prevention of PPH and do not have access to oxytocin for treatment. Adding misoprostol to standard uterotonics has no additional benefits to women being treated for PPH, but the beneficial adjunctive role of misoprostol to conventional uterotonics is important in reducing intra- and postoperative hemorrhage during cesarean section.ConclusionMisoprostol is an effective uterotonic agent in the treatment of PPH. Clinical guidelines and treatment protocols should be updated to reflect the current knowledge on the efficacy of misoprostol for the treatment of PPH with 800 μg sublingually

Abortion history and its association with current use of modern contraceptive methods in Luanda, Angola.

BackgroundWomen in sub-Saharan Africa often use abortion as a method of limiting their fertility and spacing births. However, it is not well understood whether having an abortion influences contraceptive behavior. The goal of this study was to examine associations between abortion history and use of a modern contraceptive method among women in Luanda, Angola.Materials and methodsWe analyzed data on 1,176 women aged 15-49 years from a 2012 cross-sectional study conducted in Luanda, Angola, which aimed to obtain general information on sexual and reproductive health indicators. The outcome and exposure were based on participant reports of past induced abortions and current use of a modern method. We used a modified Poisson regression with robust standard errors to estimate the relative risks of using a modern contraceptive method, given history of induced abortion.ResultsAmong all respondents, 736 (62.6%) reported using a modern contraceptive method. The clear majority of the respondents (73.21%), regardless of abortion history, were using either no method, a traditional method, or condoms. Long-acting reversible contraceptive use was very low across all respondents (2.73%). The most common family planning method reported by women with a history of abortion was condoms (32.76%). Regression analysis demonstrated that women who had a history of abortion were 1.23 times more likely to use a modern contraceptive method as compared to those who never had an abortion (relative risk: 1.23; 95% CI: 1.10-1.36), after adjusting for potential confounders. Postregression estimations of predicted probabilities demonstrated that women with a history of abortion had an 80% probability of using a modern method (95% CI: 0.76-0.84), while those who never had an abortion had a 60% probability of using a modern method (95% CI: 0.59-0.61).ConclusionHistory of induced abortion was associated with use of a modern contraceptive method in our study population. The most common contraceptive used by women with a history of induced abortion was condoms, indicating that despite adoption of a modern method, many women are still at risk for an unintended pregnancy. Further research is needed to understand the causal factors underlying women's postabortion contraceptive choices

A note on chromospheric fine structure at active region polarity boundaries

High resolution H-alpha photographs for studying chromospheric fine structure at active region polarity boundarie

Vector bundles on projective varieties and representations of quivers

We present equivalences between certain categories of vector bundles on projective varieties, namely cokernel bundles, Steiner bundles, syzygy bundles, and monads, and full subcategories of representations of certain quivers. As an application, we provide decomposability criteria for such bundles.Comment: 29 pages. Partially overlaps with arXiv:1210.7835. To appear in Algebra and Discrete Mathematic

Prevention of postpartum hemorrhage in low-resource settings: current perspectives.

BackgroundPostpartum hemorrhage (PPH) is the leading cause of maternal death in low-income countries and is the primary cause of approximately one-quarter of global maternal deaths. The purpose of this paper is to provide a review of PPH prevention interventions, with a particular focus on misoprostol, and the challenges and opportunities that preventing PPH in low-resource settings presents.MethodsUsing PubMed, we conducted a review of the literature on the randomized controlled trials of interventions to prevent PPH. We then searched PubMed and Google Scholar for nonrandomized field trials of interventions to prevent PPH. We limited our review to interventions that are discussed in the current World Health Organization (WHO) recommendations for PPH prevention and present evidence regarding the use of these interventions. We focused our review on nondrug PPH prevention interventions compared with no intervention and uterotonics versus placebo; this review does not decipher the relative effectiveness of uterotonic drugs. We describe challenges to and opportunities for scaling up PPH prevention interventions.ResultsActive management of the third stage of labor is considered the "gold standard" strategy for reducing the incidence of PPH. It combines nondrug interventions (controlled cord traction and cord clamping) with the administration of an uterotonic drug, the preferred uterotonic being oxytocin. Unfortunately, oxytocin has limited application in resource-poor countries, due to its heat instability and required administration by a skilled provider. New heat-stable drugs and drug formulations are currently in development that may improve the prevention of PPH; however, misoprostol is a viable option for provision at home by a lay health care worker or the woman herself, in the interim.ConclusionAs the main cause of maternal mortality worldwide, PPH prevention interventions need to be prioritized. Increased access to prophylactic uterotonics, regardless of where deliveries occur, should be the primary means of reducing the burden of this complication