A phenomenological model of galaxy clusters

We present a simple model to describe the dark matter density, the gas density, and the gas temperature profiles of galaxy clusters. Analytical expressions for these quantities are given in terms of only five free parameters with a clear physical meaning: the mass M of the dark matter halo (or the characteristic temperature T_0), the characteristic scale radius a, the cooling radius in units of a (0<alpha<1), the central temperature in units of T_0 (0<t<1), and the asymptotic baryon fraction in units of the cosmic value (f~1). It is shown that our model is able to reproduce the three-dimensional density and temperature profiles inferred from X-ray observations of real clusters within a 20 per cent accuracy over most of the radial range. Some possible applications are briefly discussed.Comment: 7 pages, 4 figures, submitted to MNRA

Calculation of the Alpha--Particle Ground State within the Hyperspherical Harmonic Basis

The problem of calculating the four--nucleon bound state properties for the case of realistic two- and three-body nuclear potentials is studied using the hyperspherical harmonic (HH) approach. A careful analysis of the convergence of different classes of HH functions has been performed. A restricted basis is chosen to allow for accurate estimates of the binding energy and other properties of the 4He ground state. Results for various modern two-nucleon and two- plus three-nucleon interactions are presented. The 4He asymptotic normalization constants for separation in 2+2 and 1+3 clusters are also computed.Comment: 29 pages, 4 figures, 11 tables, revtex

Low energy n-\nuc{3}{H} scattering : a novel testground for nuclear interaction

The low energy n-\nuc{3}{H} elastic cross sections near the resonance peak are calculated by solving the 4-nucleon problem with realistic NN interactions. Three different methods -- Alt, Grassberger and Shandas (AGS), Hyperspherical Harmonics and Faddeev-Yakubovsky -- have been used and their respective results are compared. We conclude on a failure of the existing NN forces to reproduce the n-\nuc{3}{H} total cross section.Comment: To be published in Phys. Rev.

FEATURE SELECTION APPLIED TO THE TIME-FREQUENCY REPRESENTATION OF MUSCLE NEAR-INFRARED SPECTROSCOPY (NIRS) SIGNALS: CHARACTERIZATION OF DIABETIC OXYGENATION PATTERNS

Diabetic patients might present peripheral microcirculation impairment and might benefit from physical training. Thirty-nine diabetic patients underwent the monitoring of the tibialis anterior muscle oxygenation during a series of voluntary ankle flexo-extensions by near-infrared spectroscopy (NIRS). NIRS signals were acquired before and after training protocols. Sixteen control subjects were tested with the same protocol. Time-frequency distributions of the Cohen's class were used to process the NIRS signals relative to the concentration changes of oxygenated and reduced hemoglobin. A total of 24 variables were measured for each subject and the most discriminative were selected by using four feature selection algorithms: QuickReduct, Genetic Rough-Set Attribute Reduction, Ant Rough-Set Attribute Reduction, and traditional ANOVA. Artificial neural networks were used to validate the discriminative power of the selected features. Results showed that different algorithms extracted different sets of variables, but all the combinations were discriminative. The best classification accuracy was about 70%. The oxygenation variables were selected when comparing controls to diabetic patients or diabetic patients before and after training. This preliminary study showed the importance of feature selection techniques in NIRS assessment of diabetic peripheral vascular impairmen

Helium and Iron in X-ray galaxy clusters

I discuss the role of the sedimentation of helium in galaxy cluster cores on the observed X-ray properties and present a history of the metal accumulation in the ICM, with new calculations with respect to my previous work following the recent evidence of a bi-modal distribution of the delay time in Supernovae Type Ia.Comment: 6 pages. To appear in the Proceedings of "Heating vs. Cooling in Galaxies and Clusters of Galaxies", August 2006, Garching (Germany

Technical and economical feasibility of on-farm fish feed production using fishmeal analogs

Ten experimental diets and one control diet were fed to 720 tilapia (20 fish × 12 cages × three replicates) in a recirculating aquaculture system to determine the economic significance of replacing fishmeal with fishmeal analogs if the fishmeal analogs were processed on-site by the producer. All experimental diets were produced at Illinois State University using an Insta-Pro Model 600 Jr. extruder plus grinding, weighing and mixing equipment commonly found on commercial livestock operations. Primary diet protein sources included corn gluten meal, corn gluten feed and distillers dried grains. All diets were balanced for amino acid requirements of the fish, and both 32 and 36% crude protein diets were fed. There was no significant difference in feed conversion ratio (FCR) between diets with fishmeal and diets without fishmeal. There was no significant difference in FCR between 32 and 36% crude protein diets. An economic engineering model which included all equipment necessary for extruding and handling pelleted feed on-site was developed. Annualized investment and operating costs were estimated to determine the total cost of processing each of the 10 experimental diets. There was a significant difference in cost of gain among the 10 experimental diets and the control diet. Cost of production was highly sensitive to volume of feed extruded

Galaxy pre-processing in substructures around z∼\sim0.4 galaxy clusters

We present a detailed analysis of galaxy colours in two galaxy clusters at \mbox{z $\sim$ 0.4}, \mbox{MACS J0416.1-2403} and \mbox{MACS J1206.2-0847}, drawn from the CLASH-VLT survey, to investigate the role of pre-processing in the quenching of star formation. We estimate the fractions of red and blue galaxies within the main cluster and the detected substructures and study the trends of the colour fractions as a function of the projected distance from the cluster and substructure centres. Our results show that the colours of cluster and substructure members have consistent spatial distributions. In particular, the colour fractions of galaxies inside substructures follow the same spatial trends observed in the main clusters. Additionally, we find that at large cluster-centric distances \mbox{($r \geq r_{200}$)} the fraction of blue galaxies in both the main clusters and in the substructures is always lower than the average fraction of UVJ-selected star-forming galaxies in the field as measured in the COSMOS/UltraVista data set. We finally estimate environmental quenching efficiencies in the clusters and in the substructures and find that at large distances from the cluster centres, the quenching efficiency of substructures becomes comparable to the quenching efficiency of clusters. Our results suggest that pre-processing plays a significant role in the formation and evolution of passive galaxies in clusters at low redshifts.Comment: Accepted for publication in MNRAS. 28 pages, 14 figures, 20 table

GAME: Grb and All-sky Monitor Experiment

We describe the GRB and All-sky Monitor Experiment (GAME) mission submitted by a large international collaboration (Italy, Germany, Czech Repubblic, Slovenia, Brazil) in response to the 2012 ESA call for a small mission opportunity for a launch in 2017 and presently under further investigation for subsequent opportunities. The general scientific objective is to perform measurements of key importance for GRB science and to provide the wide astrophysical community of an advanced X-ray all-sky monitoring system. The proposed payload was based on silicon drift detectors (~1-50 keV), CdZnTe (CZT) detectors (~15-200 keV) and crystal scintillators in phoswich (NaI/CsI) configuration (~20 keV-20 MeV), three well established technologies, for a total weight of ~250 kg and a required power of ~240 W. Such instrumentation allows a unique, unprecedented and very powerful combination of large field of view (3-4 sr), a broad energy energy band extending from ~1 keV up to ~20 MeV, an energy resolution as good as ~300 eV in the 1-30 keV energy range, a source location accuracy of ~1 arcmin. The mission profile included a launch (e.g., by Vega) into a low Earth orbit, a baseline sky scanning mode plus pointed observations of regions of particular interest, data transmission to ground via X-band (4.8 Gb/orbit, Alcantara and Malindi ground stations), and prompt transmission of GRB / transient triggers.Comment: 13 pages, 8 figures, published in International Journal of Modern Physics