Can dissipation prevent explosive decomposition in high-energy heavy ion collisions?

We discuss the role of dissipation in the explosive spinodal decomposition scenario of hadron production during the chiral transition after a high-energy heavy ion collision. We use a Langevin description inspired by microscopic nonequilibrium field theory results to perform real-time lattice simulations of the behavior of the chiral fields. We show that the effect of dissipation can be dramatic. Analytic results for the short-time dynamics are also presented. (c) 2005 Elsevier B.V. All rights reserved.

De Sitter Relativity: a New Road to Quantum Gravity?

The Poincar, group generalizes the Galilei group for high-velocity kinematics. The de Sitter group is assumed to go one step further, generalizing Poincar, as the group governing high-energy kinematics. In other words, ordinary special relativity is here replaced by de Sitter relativity. In this theory, the cosmological constant I > is no longer a free parameter, and can be determined in terms of other quantities. When applied to the whole universe, it is able to predict the value of I > and to explain the cosmic coincidence. When applied to the propagation of ultra-high energy photons, it gives a good estimate of the time delay observed in extragalactic gamma-ray flares. It can, for this reason, be considered a new paradigm to approach the quantum gravity problem.

Searching for squeezed particle-antiparticle correlations in high-energy heavy-ion collisions

Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high-energy heavy-ion collisions. Although well-established theoretically, they have not yet been observed experimentally. We suggest here a clear method to search for such a signal by analyzing the squeezed correlation functions in terms of measurable quantities. We illustrate this suggestion for simulated phi phi pairs at the Relativistic Heavy Ion Collider (RHIC) energies.

Squeezed K+K- correlations in high energy heavy ion collisions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biomimetic apatite formation on Ultra-High Molecular Weight Polyethylene (UHMWPE) using modified biomimetic solution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On Ti-18Si-6B and Ti-7.5Si-22.5B powder alloys prepared by high-energy ball milling and sintering

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoluminescence of nanostructured PbTiO3 processed by high-energy mechanical milling

This letter reports on a process to prepare nanostructured PbTiO3 (PT) at room temperature with photoluminescence (PL) emission in the visible range. This process is based on the high-energy mechanical milling of ultrafine PbTiO3 powder. The results suggest that high-energy mechanical milling modifies the particle's structure, resulting in localized states in an interfacial region between the crystalline PT and the amorphous PT. These localized states are believed to be responsible for the PL obtained with short milling times. When long milling times are employed, the amorphous phase that is formed causes PL behavior. An alternative method to process nanostructured wide-band-gap semiconductors with active optical properties such as PL is described in this letter. (C) 2001 American Institute of Physics.

Performance of an operating high energy physics data grid: DOSAR-Grid

The DO experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of DO collaborators poses further serious difficulties for optimal use of human and computing resources. These difficulties will exacerbate in future high energy physics experiments, like the LHC. The computing grid has long been recognized as a solution to these problems. This technology is being made a more immediate reality to end users in DO by developing a grid in the DO Southern Analysis Region (DOSAR), DOSAR-Grid, using a available resources within it and a home-grown local task manager, McFarm. We will present the architecture in which the DOSAR-Grid is implemented, the use of technology and the functionality of the grid, and the experience from operating the grid in simulation, reprocessing and data analyses for a currently running HEP experiment.

High resolution ultra high pressure liquid chromatography-time-of-flight mass spectrometry dereplication strategy for the metabolite profiling of Brazilian Lippia species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and properties of nanocrystalline WO3/TiO2-based humidity sensors elements prepared by high energy activation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bulk and high-energy ball-milled Gd5Si2Ge2: Comparative study of magnetic and magnetocaloric properties

High-energy ball milling was employed to produce small particles of Gd5Si2Ge2. Magnetic and magnetocaloric properties of the ball-milled and bulk Gd5Si2Ge2 samples were investigated through the magnetization measurements. When compared to the bulk material, a significant decrease in saturation magnetization and magnetocaloric effect (-Delta S-max = 4 vs. 20 J/kgK for Delta H = 0-5 T) is observed even after the relatively short ball milling time of 4 h which produced particles with an average size of ca. 0.5 mu m. The ball-milled samples appear to loose a first-order structural transition, present in bulk Gd5Si2Ge2, and display a superparamagnetic behaviour below the corresponding Curie temperatures. (C) 2010 Elsevier Masson SAS. All rights reserved.

Atmospheric cosmic rays in the South Atlantic anomaly region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.

Inelasticity distributions in high-energy p-nucleus collisions

Inelasticity distributions in high-energy p-nucleus collisions are computed in the framework of the interacting gluon model, with the impact-parameter fluctuation included. A proper account of the peripheral events by this fluctuation has shown to be vital for the overall agreement with several reported data. The energy dependence is found to be weak.

The adverse effect of a high energy dense diet on cardiac tissue

Purpose: To determine whether a high energy dense diet intake increases oxidative stress and alters antioxidant enzymes in cardiac tissue. Design: A randomized, controlled study. Ninety-day-old female rats were randomly divided into two groups: one fed with a low energy dense diet (LE; 3.0 kcal g-1) and one with a high energy dense diet (HE; 4.5 kcal g-1). Materials and Methods: After 8 weeks of treatment, the animals were fasted overnight and sacrificed by decapitation. The serum was used for glucose, triacylglycerol, cholesterol, low-density lipoprotein (LDL)-cholesterol and high-density lipoprotein (HDL)-cholesterol determinations. The glycogen, lipoperoxide, lipid hydroperoxide, superoxide dismutase, glutathione peroxidase, lactate dehydrogenase, citrate synthase, total and non-protein sulphhydryl groups were determined in cardiac tissue. Results: HE decreased the myocardial glycogen content and increased the lactate dehydrogenase/citrate synthase ratio, indicating an increased glycolytic pathway and a shift from myocardial aerobic metabolism. HE-treated female rats showed increased lipoperoxide and hydroperoxide levels in cardiac tissue. Although no alterations were observed in the total sulphhydryl group and superoxide dismutase activities, glutathione peroxidase and the non-protein sulphhydryl group were significantly decreased in HE-treated animals. Conclusions: Although no alterations were observed in energy intake, HE induced an increased intake of fat and carbohydrate and an increased rate of weight gain. HE intake induced alterations in markers of oxidative stress in cardiac tissue. Hydrogen peroxide is an important toxic intermediate in the development of cardiac oxidative stress by HE. The specific nutrient content, such as fat and carbohydrate, rather than caloric intake, appears to be the main process inducing oxidative stress in HE-treated female rats.

Performance of the CMS drift-tube chamber local trigger with cosmic rays

The performance of the Local Trigger based on the drift-tube system of the CMS experiment has been studied using muons from cosmic ray events collected during the commissioning of the detector in 2008. The properties of the system are extensively tested and compared with the simulation. The effect of the random arrival time of the cosmic rays on the trigger performance is reported, and the results are compared with the design expectations for proton-proton collisions and with previous measurements obtained with muon beams. © 2010 IOP Publishing Ltd and SISSA.