Dissipative N - body code for galaxy evolution

The evolving galaxy is considered as a system of baryonic fragments embedded into the static dark nonbaryonic (DH) and baryonic (BH) halo and subjected to gravitational and viscous interactions. Although the chemical evolution of each separate fragment is treated in the frame of one -- zone close box model with instantaneous recycling, its star formation (SF) activity is a function of mean local gas density and, therefore, is strongly influenced by other interacting fragments. In spite of its simplicity this model provides a realistic description of the process of galaxy formation and evolution over the Hubble timescale.Comment: 11 pages, LaTeX, 7 figures, using the article.sty, expected in A&ApTr, 18, 83

GARFIELD + RCo Digital Upgrade: a Modern Set-up for Mass and Charge Identification of Heavy Ion Reaction Products

An upgraded GARFIELD + Ring Counter (RCo) apparatus is presented with improved performances as far as electronics and detectors are concerned. On one side fast sampling digital read out has been extended to all detectors, allowing for an important simplification of the signal processing chain together with an enriched extracted information. On the other side a relevant improvement has been made in the forward part of the setup (RCo): an increased granularity of the CsI(Tl) crystals and a higher homogeneity in the silicon detector resistivity. The renewed performances of the GARFIELD + RCo array make it suitable for nuclear reaction measurements both with stable and with Radioactive Ion Beams (RIB), like the ones foreseen for the SPES facility, where the Physics of Isospin can be studied.Comment: 13 pages, 19 figures - paper submitted to Eur. Phys. J.

PEN: a low energy test of lepton universality

Allowed charged $\pi$ meson decays are characterized by simple dynamics, few available decay channels, mainly into leptons, and extremely well controlled radiative and loop corrections. In that sense, pion decays represent a veritable triumph of the standard model (SM) of elementary particles and interactions. This relative theoretical simplicity makes charged pion decays a sensitive means for testing the underlying symmetries and the universality of weak fermion couplings, as well as for studying pion structure and chiral dynamics. Even after considerable recent improvements, experimental precision is lagging far behind that of the theoretical description for pion decays. We review the current state of experimental study of the pion electronic decay $\pi^+ \to e^+\nu_e(\gamma)$, or $\pi_{e2(\gamma)}$, where the $(\gamma)$ indicates inclusion and explicit treatment of radiative decay events. We briefly review the limits on non-SM processes arising from the present level of experimental precision in $\pi_{e2(\gamma)}$ decays. Focusing on the PEN experiment at the Paul Scherrer Institute (PSI), Switzerland, we examine the prospects for further improvement in the near term.Comment: 11 pages, 5 figures; paper presented at the XIII International Conference on Heavy Quarks and Leptons, 22-27 May 2016, Blacksburg, Virginia, US

Isotope analysis in central heavy ion collisions at intermediate energies

Symmetry energy is a key quantity in the study of the equation of state of asymmetric nuclear matter. Heavy ion collisions at low and intermediate energies, performed at Laboratori Nazionali di Legnaro and Laboratori Nazionali del Sud, can be used to extract information on the symmetry energy coefficient Csym, which is currently poorly known but relevant both for astrophysics and for structure of exotic nuclei.Comment: 2 pages, 1 figure. Proceedings of 7th International Conference on Radioactive Nuclear Beams (RNB7), to be published in The European Physical Journal

Search for astro-gravity correlations

A new approach in the gravitational wave experiment is considered. In addition to the old method of searching for coincident reactions of two separated gravitational antennae it was proposed to seek perturbations of the gravitational detector noise background correlated with astrophysical events such as neutrino and gamma ray bursts which can be relaibly registered by correspondent sensors. A general algorithm for this approach is developed. Its efficiency is demonstrated in reanalysis of the old data concerning the phenomenon of neutrino-gravity correlation registered during of SN1987A explosion.Comment: 29 pages (LaTeX), 4 figures (EPS

Evaluation of the effectiveness of weight loss and the return of lost weight after sleeve gastrectomy in the long term follow-up period

Sleeve gastrectomy, originally proposed as part of a two-stage operation, more than 15 years ago, is recognized as an independent, effective intervention for the treatment of obesity. The purpose of this review was to evaluate the effectiveness of sleeve gastrectomy based on data on long-term follow-up of patients. A search was performed in two databases, 33 literary sources were selected based on the results of the selection. In this review, the authors evaluated some parameters characterizing the effectiveness of sleeve gastrectomy in the long term after surgery. The percentage of follow-up of patients in the long-term period (follow up, %) varied from 5,6% to 97%, the expected decrease in % follow up over time did not occur. The authors have suggested similar results due to the heterogeneity of the data of the analyzed sources. By the five-year period, the detected average % of follow-up did not correspond to the optimal recommended level of follow-up for operated patients by this time. The most common criterion for assessing the return of weight is an increase in body weight by more than 10 kg from the lowest achieved. The prevalence of this phenomenon ranged from 26.3% to 44%. Among the reasons predisposing to weight loss are the initial high BMI, old age, dilatation of the formed stomach. In the absence of a universal definition of various terms (follow up, unsatisfactory result of surgery, weight loss, etc.), the results among the same patients when using different definitions will differ, there is a need to adopt standards when describing these phenomena. Despite the likelihood of weight loss after longitudinal resection, this operation is relatively simple from a technical point of view, safer, it can be used to improve the course of concomitant pathology (diabetes mellitus, hypertension), improve the quality and increase the life expectancy of patients

Vortex Polarity Switching in Magnets with Surface Anisotropy

Vortex core reversal in magnetic particle is essentially influenced by a surface anisotropy. Under the action of a perpendicular static magnetic field the vortex core undergoes a shape deformationof pillow- or barrel-shaped type, depending on the type of the surface anisotropy. This deformation plays a key point in the switching mechanism: We predict that the vortex polarity switching is accompanied (i) by a linear singularity in case of Heisenberg magnet with bulk anisotropy only and (ii) by a point singularities in case of surface anisotropy or exchange anisotropy. We study in details the switching process using spin-lattice simulations and propose a simple analytical description using a wired core model, which provides an adequate description of the Bloch point statics, its dynamics and the Bloch point mediated switching process. Our analytical predictions are confirmed by spin-lattice simulations for Heisenberg magnet and micromagnetic simulations for nanomagnet with account of a dipolar interaction.Comment: 17 pages, 15 figure

PEN experiment: a precise measurement of the pi+ -> e+ nu decay branching fraction

A new measurement of $B_{\pi e2}$, the $\pi^+ \to e^+\nu(\gamma)$ decay branching ratio, is currently under way at the Paul Scherrer Institute. The present experimental result on $B_{\pi e2}$ constitutes the most accurate test of lepton universality available. The accuracy, however, still lags behind the theoretical precision by over an order of magnitude. Because of the large helicity suppression of the $\pi_{e2}$ decay, its branching ratio is susceptible to significant contributions from new physics, making this decay a particularly suitable subject of study.Comment: 4 pages, 3 figures, talk given at the Tenth Conference on the Intersections of Particle and Nuclear Physics (CIPANP 2009), La Jolla/San Diego, CA, 26-31 May 2009; to appear in Proceedings to be published by the American Institute of Physic