Transverse Momentum Spectra of Pions in Particle and Nuclear Collisions and Some Ratio-Behaviours: Towards A Combinational Approach

The nature of transverse momentum dependence of the inclusive cross-sections for secondary pions produced in high energy hadronic($PP$), hadronuclear($PA$) and nuclear($AA$) collisions has here been exhaustively investigated for a varied range of interactions in a unified way with the help of a master formula. This formula evolved from a new combination of the basic Hagedorn's model for particle(pion) production in PP scattering at ISR range of energies, a phenomenological approach proposed by Peitzmann for converting the results of $NN(PP)$ reactions to those for either $PA$ or $AA$ collisions, and a specific form of parametrization for mass number-dependence of the nuclear cross sections. This grand combination of models(GCM) is then applied to analyse the assorted extensive data on various high energy collisions. The nature of qualitative agreement between measurements and calculations on both the inclusive cross-sections for production of pions, and some ratios of them as well, is quite satisfactory. The modest successes that we achieve here in dealing with the massive data-sets are somewhat encouraging in view of the diversity of the reactions and the very wide range of interaction energies.Comment: 19 pages, 19 figure

Technology use, adoption and behaviour in older adults: results from the iStoppFalls Project

Technology use is a common constituent of modern life. However, little is known about older adults’ use of technology. This article presents a subset of data collected via the technology deployed in the iStoppFalls randomized control trial. The primary focus lies on questions about digital device/Internet use, ownership, length, and frequency as well as social networking. Data was collected from participants aged 65 years or older. Seventy-eight participants completed a specifically developed technology survey as part of the baseline assessment. Results showed that the majority of subjects owned a computer with men being its main user. Participants used technological devices on a daily basis for more than 1 year. The main reason for using technology was e-mail communication, search engines, text processing, and online shopping. Only a few participants used social network applications, with Google+ and Facebook being the most popular ones. Future work should consider an in-depth qualitative approach to further increase understanding of technology use in older adults

Medium effects in high energy heavy-ion collisions

The change of hadron properties in dense matter based on various theoretical approaches are reviewed. Incorporating these medium effects in the relativistic transport model, which treats consistently the change of hadron masses and energies in dense matter via the scalar and vector fields, heavy-ion collisions at energies available from SIS/GSI, AGS/BNL, and SPS/CERN are studied. This model is seen to provide satisfactory explanations for the observed enhancement of kaon, antikaon, and antiproton yields as well as soft pions in the transverse direction from the SIS experiments. In the AGS heavy-ion experiments, it can account for the enhanced $K^+/\pi^+$ ratio, the difference in the slope parameters of the $K^+$ and $K^-$ transverse kinetic energy spectra, and the lower apparent temperature of antiprotons than that of protons. This model also provides possible explanations for the observed enhancement of low-mass dileptons, phi mesons, and antilambdas in heavy-ion collisions at SPS energies. Furthermore, the change of hadron properties in hot dense matter leads to new signatures of the quark-gluon plasma to hadronic matter transition in future ultrarelativistic heavy-ion collisions at RHIC/BNL.Comment: RevTeX, 65 pages, including 25 postscript figures, invited topical review for Journal of Physics G: Nuclear and Particle Physic

The gravitational wave detector VIRGO

International audienc

Trace metal distribution in the bed, bank and suspended sediment of the Ravensbourne River and its implication for sediment monitoring in an urban river

Purpose This study aims to identify a suitable sediment compartment for sediment quality monitoring by: (a) studying the concentration of trace metals (Cd, Cu, Ni, Pb and Zn) in the bed, bank and suspended sediment compartments of the Ravensbourne River to establish any differences in trace metal concentrations with compartment; (b) determining the influence of sediment particle size fractions ( 0.05) in the concentrations of metals between the suspended sediment and the < 63 μm bed sediment fraction, but there was a significant difference (p < 0.05) between the suspended sediment and the < 63 μm bank sediment fraction. There were also significant differences between the concentrations of metals in the < 63 μm and the 63 μm–2 mm fractions. Generally, the Ravensbourne River did not comply with the draft UK sediment quality guidelines for the metals analysed. Conclusions This study shows the importance of identifying a suitable sediment compartment to sample for compliance with sediment quality standards. The bed and suspended sediments are the most widely used sediment compartments for sediment monitoring, but collecting sufficient mass of the < 63 μm sediment fraction for monitoring presents a challenge for urban gravel bed rivers like the Ravensbourne River. It seems appropriate to establish individual monitoring regimes for different rivers

Total and exchangeable concentrations of heavy metals in soils near Bytom, an area of Pb/Zn mining and smelting in Upper Silesia, Poland

High concentrations of several heavy metals were suspected in soils in an area of some contemporary and extensive historical mining and smelting of Pb and Zn near the town of Bytom. In order to investigate the spatial distribution of heavy metals, 152 soil samples were taken at high sampling density in an area of 14 km2 on a regular grid as well as along an 11 km transect. The samples were analysed for total Pb, Zn and Cd content by ICP-AES; a selection of samples were also analysed for total As content. Significant levels of contamination were found. Median topsoil concentrations (0-10 cm) for Pb, Cd, Zn and As were 430 ug g-1, 13 ug g-1, 1245 ug g-1 and 35 ug g-1, respectively. The detected levels of Pb, Zn and Cd were mostly in reasonable agreement with findings from a previous low-density study, but arsenic concentrations were up to 6 times higher than had previously been reported for the area. Additional zones of particularly high concentrations could be identified for all four elements by this higher-density survey. Contaminant concentrations were generally found to decrease substantially with increasing depth, on average by a factor of 3.5 for Cd, 3.0 for Zn and 2.6 for Pb. However, significant subsoil contamination (40-50 cm) was also detected, in particular for Zn, Pb and As, which appeared to be enriched at depth in certain locations. To assess the potential availability of the metals to plants, the exchangeable fraction (0.5 M MgCl2) was estimated for Pb, Zn and Cd for 84 samples. Levels were strongly influenced by soil pH and were generally low for Pb (less than 1% of total, max 15.6%), moderate for Zn (less than 10% of total, max 32.4%), and high for Cd (mean 35% of total, max 59.8%). For Zn and Pb, there seemed to be a threshold pH value of about 6, below which a significant increase in the exchangeable fraction was observed. No such threshold value appeared to exist for Cd, which was found to be relatively labile even in slightly alkaline soils (mean of 27.6% exchangeable Cd in pH range 7–8).The detected levels of total metal contamination exceed various national and international thresholds, indicating the need for further investigation and an assessment of the suitability of the land for agricultural use, particularly in view of the high levels of exchangeable Cd.The pattern of spatial variation of the metals in the topsoil indicates that a variety of sources might be responsible for the contamination, historical mining and smelting probably being the most important.<br/