Diffuse gamma-ray background and cosmic-ray positrons from annihilating dark matter

We study the annihilating dark matter contribution to the extra-galactic diffuse gamma-ray background spectrum, motivated by the recent observations of cosmic-ray positron/electron anomalies. The observed diffuse gamma-ray flux provides stringent constraint on dark matter models and we present upper bounds on the annihilation cross section of the dark matter. It is found that for the case of cored dark matter halo profile, the diffuse gamma-rays give more stringent bound compared with gamma-rays from the Galactic center. The Fermi satellite will make the bound stronger.Comment: 20 pages, 11 figures; references added; to appear in PR

Quantitative modeling of \textit{in situ} x-ray reflectivity during organic molecule thin film growth

Synchrotron-based x-ray reflectivity is increasingly employed as an \textit{in situ} probe of surface morphology during thin film growth, but complete interpretation of the results requires modeling the growth process. Many models have been developed and employed for this purpose, yet no detailed, comparative studies of their scope and accuracy exists in the literature. Using experimental data obtained from hyperthermal deposition of pentane and diindenoperylene (DIP) on SiO$_2$, we compare and contrast three such models, both with each other and with detailed characterization of the surface morphology using ex-situ atomic force microscopy (AFM). These two systems each exhibit particular phenomena of broader interest: pentacene/SiO$_2$ exhibits a rapid transition from rough to smooth growth. DIP/SiO$_2$, under the conditions employed here, exhibits growth rate acceleration due to a different sticking probability between the substrate and film. In general, \textit{independent of which model is used}, we find good agreement between the surface morphology obtained from fits to the \insitu x-ray data with the actual morphology at early times. This agreement deteriorates at later time, once the root-mean squared (rms) film roughness exceeds about 1 ML. A second observation is that, because layer coverages are under-determined by the evolution of a single point on the reflectivity curve, we find that the best fits to reflectivity data --- corresponding to the lowest values of $\chi_\nu^2$ --- do not necessarily yield the best agreement between simulated and measured surface morphologies. Instead, it appears critical that the model reproduce all local extrema in the data. In addition to showing that layer morphologies can be extracted from a minimal set of data, the methodology established here provides a basis for improving models of multilayer growth by comparison to real systems.Comment: 34 pages (double-spaced, including figures and references), 10 figures, 3 appendice

Escalation Of Commitment In MIS Projects: A Meta-Analysis

Escalation of commitment emerged as a major explanation for the propensity of management information systems projects to exceed time and budget constraints. Earlier studies demonstrated that escalation in MIS is a common event.  This study presents a meta-analysis of the various theories of escalation that allows for integration of the various escalation factors into a model of irrational escalation and a model of rational escalation. The implications of rational and irrational escalation for the decision making in management of information systems are discussed

Uniqueness of qq-shift difference polynomials of meromorphic functions sharing a small function

summary:We investigate the uniqueness of a $q$-shift difference polynomial of meromorphic functions sharing a small function which extend the results of N. V. Thin (2017) to $q$-difference operators

Rupture uterus: a prospective observational study of 25 consecutive cases in a tertiary referral centre in South India

Background: Uterine rupture in pregnancy is a rare though catastrophic complication with a high incidence of foetal and maternal morbidity. It appeared to be on the decline in recent times, prompting us to analyse the clinical picture now. The objective of the study was to study the risk factors, clinical profile and consequences of uterine rupture on maternal and perinatal outcome.Methods: A prospective observational study of 25 consecutive cases of uterine rupture was carried out between July 2013 and October 2015. All the cases of rupture uterus either referred or diagnosed after admission were included. Detailed demographic data, past and present obstetric events, time taken to reach the referral centre, the reasons for any delay, mode of presentation, type of rupture, management and maternal and foetal outcomes were analysed.Results: The incidence of rupture was 1 in 915 deliveries. Seventy-two per cent of them were referred cases. Average time to reach from referral centre was 4.3 hours, the common reasons for delay being patient factors (33%), transport problems (38%) and delayed referrals (22%). Previous caesarean section was the most common predisposing factor (56%). Sixty-four per cent of the ruptures were diagnosed clinically. Eighty-four per cent of the ruptures were complete. Sub-total hysterectomy was carried out in 14 (56%) patients. Internal iliac artery ligation (20%) and bladder repair (8%) were sometimes required. All women required blood transfusion.  Perinatal mortality was seen in 76%. There was no maternal mortality.Conclusions: Uterine rupture is a cause of severe acute maternal morbidity and very high perinatal mortality.  Delay in referral and diagnosis can lead to significant maternal morbidity and hysterectomy

Calcifying Ghost Cell Odontogenic Cyst: Report of a Case and Review of Literature

The calcifying ghost cell odontogenic cyst (CGCOC) was first described by Gorlin et al. in 1962. Calcifying ghost cell odontogenic cyst is comparatively rare in occurrence, constituting about 0.37% to 2.1% of all odontogenic tumors. The most notable features of this pathologic entity are histopathological features which include a cystic lining demonstrating characteristic “Ghost” epithelial cells with a propensity to calcify. In addition, the CGCOC may be associated with other recognized odontogenic tumors, most commonly odontomas. There are variants of CGCOC according to clinical, histopathological, and radiological characteristics. Therefore a proper categorization of the cases is needed for better understanding of the pathogenesis of each variant. Here, we report a classical case of calcifying odontogenic cyst along with a brief review of literature