Non-linear shock acceleration and high energy gamma rays from clusters of galaxies

Merger and accretion shocks in clusters of galaxies can accelerate particles via first order Fermi process. Since this mechanism is believed to be intrinsically efficient, shocks are expected to be modified by the backreaction of the accelerated particles. Such a modification might induce appreciable effects on the non--thermal emission from clusters and a suppression of the heating of the gas at strong shocks. Here we consider in particular the gamma ray emission and we discuss the capability of Cherenkov telescopes such as HESS to detect clusters at TeV energies.Comment: 6 pages, to appear in the proceedings of the Gamma 2004 Symposium on High Energy Gamma Ray Astronomy, Heidelberg, July 2004 (AIP Proceedings Series

Development of a space qualified high reliability rotary actuator for spaceflight use. Volume 2: Appendices to technical report

A space-qualified, high reliability, 150 ft-lb rated torque rotary actuator is described. This drive is an integrated variable reluctance orbit motor-epicyclic transmission actuator. The performance goals were based on future control moment gyrotorquer applications and represent an advancement in the torque-to-weight ratio, backlash, inertia and response characteristics of electric rotary drives. The program accomplishments have been in two areas (1) the development of two high ratio (818:1) actuator configurations (breadboard and flightweight) and (2) the invention of a reliable proximity switch sensor system for self-commutation without use of optical or electrical brush techniques

Seeing the light : experimental signatures of emergent electromagnetism in a quantum spin ice

The "spin ice" state found in the rare earth pyrochlore magnets Ho2Ti2O7 and Dy2Ti2O7 offers a beautiful realisation of classical magnetostatics, complete with magnetic monopole excitations. It has been suggested that in "quantum spin ice" materials, quantum-mechanical tunnelling between different ice configurations could convert the magnetostatics of spin ice into a quantum spin liquid which realises a fully dynamical, lattice-analogue of quantum electromagnetism. Here we explore how such a state might manifest itself in experiment, within the minimal microscopic model of a such a quantum spin ice. We develop a lattice field theory for this model, and use this to make explicit predictions for the dynamical structure factor which would be observed in neutron scattering experiments on a quantum spin ice. We find that "pinch points", seen in quasi-elastic scattering, which are the signal feature of a classical spin ice, fade away as a quantum ice is cooled to its zero-temperature ground state. We also make explicit predictions for the ghostly, linearly dispersing magnetic excitations which are the "photons" of this emergent electromagnetism. The predictions of this field theory are shown to be in quantitative agreement with Quantum Monte Carlo simulations at zero temperature.Comment: 26 pages, 18 figures, minor revision

Introduction to the Special Section on 3DTV

Cataloged from PDF version of article.The set of six papers that we invited to this part of the Special Section present extensive reviews of the state-of-the-art in functional building blocks of 3DTV systems

Prevalence of cellular leiomyoma and partially cellular leiomyoma in postoperative samples — analysis of 384 cases

Objectives: The aim of the study was to evaluate the prevalence of cellular leiomyomas and partially cellular leiomyomas in postoperative samples. Material and methods: A total of 2144 cases of uterine leiomyomas were diagnosed in postoperative samples at the Department of Obstetrics and Gynecology, RSzS, Radom, Poland, between 1998 and 2014. We analyzed 384 cases which were subdivided into 4 groups, taking into account the co-occurrence of leiomyomas and/or endometriosis. The following variables were investigated: age, weight, BMI, parity, type of surgical procedure, prevalence of atypical and borderline tumor forms, and concomitant malignancy of the reproductive system. Results: The prevalence of cellular leiomyomas and partially cellular leiomyomas was estimated at 17.9%. Nulliparous patients were significantly more numerous in the subgroups without endometriosis. Concomitant malignancy of the reproductive system was > 2 fold more commonin the subgroups with endometriosis as compared to the other subgroups. Conclusions: The fact that cellular leiomyomas have a varying degree of cell atypia, together with clinical observations reported in the literature, support the view that cellular leiomyomas and partially cellular leiomyomas can progress to malignant leiomyosarcoma (LMS). Hysterectomy and the subsequent follow-up should be the mainstay of therapy for cellular leiomyoma. Conservative management (myomectomy) should be recommended only tothose patients who wish to preserve their fertility

Clinical analysis of 52 obstetric hysterectomies

Objectives: Analysis of obstetric (peripartum and postpartum) hysterectomies with regard to their frequency, indications, complications, and risk factors. Material and methods: The study included 52 women operated between 1985–2012. Obstetric hysterectomies were performed in 39 (75%) and 13 (25%) women, respectively. The results were statistically analyzed as arithmetic mean and standard deviation (SD). Results: Peri- and postpartum hysterectomies accounted for 0.123% of all births (0.092% and 0.031%, respectively). Mean pa­tient age, length of pregnancy, and number of deliveries was 32.6 years [SD ± 6.2], 38.1 weeks [SD ± 7.0], and 3.2 [SD ± 2.4], respectively. In the study group, 92.31% of the women were multiparous, and 86.54% gave birth by cesarean section and had a history of CS. Placental pathology accounted for 44.4% of indications for hysterectomy. Blood transfusion was required in 94.2% of the cases, symptoms of hypovolemic shock were observed in 21.2%, and ICU admission was required in 15.4% of the patients. Relaparotomy was necessary in 4 (7.7%) cases. Intrauterine fetal death occurred in 4 (7.6%) cases and extremely poor neonatal status was observed in 4.1% of the newborns. Conclusions: Hemorrhage due to placental pathology was the most frequent indication for obstetric hysterectomy. Risk factors for obstetric hysterectomy included multiparity, history of CS, recent CS, and age > 35 years. Postpartum hysterec­tomy accounted for 25% of the obstetric surgeries