Symmetry Energy Effects on Low Energy Dissipative Heavy Ion Collisions

We investigate the reaction path followed by Heavy Ion Collisions with exotic nuclear beams at low energies. We focus on the interplay between reaction mechanisms, fusion vs. break-up (fast-fission, deep-inelastic), that in exotic systems is expected to be influenced by the symmetry energy term at densities around the normal value. The method described here, based on the event by event evolution of phase space quadrupole collective modes, will nicely allow to extract the fusion probability at relatively early times, when the transport results are reliable. Fusion probabilities for reactions induced by 132Sn on 64,58Ni targets at 10 AMeV are evaluated. We obtain larger fusion cross sections for the more n-rich composite system, and, for a given reaction, with a soft symmetry term above saturation. A collective charge equilibration mechanism (the Dynamical Dipole Resonance, DDR) is revealed in both fusion and break-up events, depending on the stiffness of the symmetry term just below saturation. Finally we investigate the effect of the mass asymmetry in the entrance channel for systems with the same overall isospin content and similar initial charge asymmetry. As expected we find reduced fusion probabilities for the more mass symmetric case, while the DDR strength appears not much affected. This is a nice confirmation of the prompt nature of such collective isovector mode

The Northern Route for Human dispersal in Central and Northeast Asia: New evidence from the site of Tolbor-16, Mongolia.

The fossil record suggests that at least two major human dispersals occurred across the Eurasian steppe during the Late Pleistocene. Neanderthals and Modern Humans moved eastward into Central Asia, a region intermittently occupied by the enigmatic Denisovans. Genetic data indicates that the Denisovans interbred with Neanderthals near the Altai Mountains (South Siberia) but where and when they met H. sapiens is yet to be determined. Here we present archaeological evidence that document the timing and environmental context of a third long-distance population movement in Central Asia, during a temperate climatic event around 45,000 years ago. The early occurrence of the Initial Upper Palaeolithic, a techno-complex whose sudden appearance coincides with the first occurrence of H. sapiens in the Eurasian steppes, establishes an essential archaeological link between the Siberian Altai and Northwestern China . Such connection between regions provides empirical ground to discuss contacts between local and exogenous populations in Central and Northeast Asia during the Late Pleistocene

The open-air site of Tolbor 16 (Northern Mongolia): Preliminary results and perspectives.

Numerous questions remain regarding the timing and the context of Upper Paleolithic emergence in Northeast Asia. Available data allow the recognition of a form of Initial Upper Paleolithic (IUP) documented in the Altai circa 45e40 ka 14C BP, and in the Cis- and Transbaikal around �37 ka 14C BP. In Northern Mongolia, a series of assemblages show intriguing similarities with IUP laminar assemblages from South Siberia and suggest long distance contact/movements of population during the first half of MIS3. These contacts are potentially enabled by the main river that drains into Lake Baikal, the Selenga. By cutting through the Sayan and the Yablonovy mountain ranges, the Selenga drainage system provides a potential corridor connecting South Siberia with the plains of Mongolia. The Tolbor 16 site (Ikh Tulberiin Gol, Northern Mongolia) is located circa 13 km from the confluence with the Selenga. The first results presented here suggest that the lithic assemblage and the ornaments discovered at Tolbor 16 document the early appearance of Upper Paleolithic in the region. This newly discovered site offers the possibility to generate high-resolution contextual data on the first appearance of the blade assemblages in Mongolia and to test the ‘Selenga corridor hypothesis’

February 25, 2014 solar flare data analysis in SunPy

Solar flares are strong radiation bursts, whereas large clouds of solar material and magnetic fields that erupt at high speeds from the Sun are coronal mass ejections. Harmful radiation from a flare does not pass through the atmosphere of the Earth to physically impact humans on the ground, but can disrupt the atmosphere in the layer where GPS and communication signals travel. Flares generate results across the entire electromagnetic spectrum. They emit x-rays and ultraviolet radiation, which means extremely high temperatures during a flash. Radio waves mean that tiny fractions of particles are accelerated to high levels of energy. Most of the radiation is synchrotron radiation produced along magnetic field lines by electrons traveling along spiral paths. In this paper was monitored solar flare registered on February 25, 2015. This flare, which peaked at 00:49 am EDT from a sunspot called Active Region 1990 (AR1990), is classified as an X4.9-class flare. We have performed solar data analysis using the Python/SunPy tool. SunPy was chosen as the principle data analysis environment since it provides easy to use interfaces to the Virtual Solar Observatory (VSO)

A new Java-based application in solar physics

Solar-based flares are one of the most impressive energetic events in the solar atmosphere. Given their part of job in the solar corona's energy balance and their function playing important role in the space weather, numerous observations researched the release of energy and induction of solar flares, focusing on the solar active. National solar observatories are providing the overall network with a wealth of data, covering extensive time ranges (e.g. Solar and Heliospheric Observatory, SOHO), numerous perspectives (Solar Terrestrial Relations Observatory, STEREO), and returning a lot of information (Solar Dynamics Observatory, SDO). Specifically, the huge amount of SDO data are accessible only from a few repositories, such type of data as a full-cadence data or full-disk of scientific concern are hard to download, because of their size. To address these difficulties we have begun to build up a new solar application using the Java programming language for a stand-alone application type (GUI)

The first excited 1/2+ state in 9Be and 9B

Nuclear states observed around threshold energies provide us with interesting problems associated with the nuclear cluster structure [1, 2, 3, 4]. The first excited Jπ = 1/2+ state of 9Be [5], which is an α+ α + n Borromean nucleus, is one of the typical examples in light nuclei. This state of 9Be has been observed as a sharp peak above the 8Be + n threshold energy in the photo-disintegration cross section of γ+9Be→ α + α + n [6, 7]. The strength of the peak has a strong influence on the reaction rate of the 9Be synthesis. We performed the calculations using an α + α + n three-body model [8, 9] and the complex scaling method (CSM), which well reproduces the observed photo-disintegration cross section. However, the result indicates that the 1/2+ state shows the s-wave virtual-state character of 8Be+n. In addition to this problem, we discuss a mirror state problem of the first excite 1/2+ state in 9B

Nuclear reaction models for systematic analysis of the fast neutron induced (n,p) reaction cross sections

Taking into account compound, pre-equilibrium and direct reaction mechanisms, we suggest certain method for theoretical explanation of systematic regularity in the fast neutron induced (n,p) reaction cross sections. The statistical model, Griffin exciton model and PWBA are used. For systematical analysis of (n,p) reaction cross sections, simple and convenient formulae are deduced. It is shown that theoretical (n,p) cross sections are satisfactorily in agreement with experimental values for the 6, 8, 10, 13, 14.5, and 16 MeV neutrons