Shock Waves in Solid Craters

Shock waves in solid craters and effects of high speed impact of particles on space vehicle

Designing Environments to Enhance Physical and Psychological Benefits of Physical Activity: A Multidisciplinary Perspective.

This article is part of the Topical Collection on Designing environments to enhance physical and psychological benefits of physical activity : a multi-disciplinary perspective

Determination of S17(0) from published data

The experimental landscape for the 7Be+p radiative capture reaction is rapidly changing as new high precision data become available. We present an evaluation of existing data, detailing the treatment of systematic errors and discrepancies, and show how they constrain the astrophysical S factor (S17), independent of any nuclear structure model. With theoretical models robustly determining the behavior of the sub-threshold pole, the extrapolation error can be reduced and a constraint placed on the slope of S17. Using only radiative capture data, we find S17(0) = 20.7 +/- 0.6 (stat) +/- 1.0 (syst) eV b if data sets are completely independent, while if data sets are completely correlated we find S17(0) = 21.4 +/- 0.5 (stat) +/- 1.4 (syst) eV b. The truth likely lies somewhere in between these two limits. Although we employ a formalism capable of treating discrepant data, we note that the central value of the S factor is dominated by the recent high precision data of Junghans et al., which imply a substantially higher value than other radiative capture and indirect measurements. Therefore we conclude that further progress will require new high precision data with a detailed error budget.Comment: 10 pages, 1 figure published versio

Role of dynamical particle-vibration coupling in reconciliation of the d3/2d_{3/2} puzzle for spherical proton emitters

It has been observed that decay rate for proton emission from $d_{3/2}$ single particle state is systematically quenched compared with the prediction of a one dimensional potential model although the same model successfully accounts for measured decay rates from $s_{1/2}$ and $h_{11/2}$ states. We reconcile this discrepancy by solving coupled-channels equations, taking into account couplings between the proton motion and vibrational excitations of a daughter nucleus. We apply the formalism to proton emitting nuclei $^{160,161}$Re to show that there is a certain range of parameter set of the excitation energy and the dynamical deformation parameter for the quadrupole phonon excitation which reproduces simultaneously the experimental decay rates from the 2$d_{3/2}$, 3$s_{1/2}$ and 1$h_{11/2}$ states in these nuclei.Comment: RevTex, 12 pages, 4 eps figure

Alcohol use and problem drinking in South Africa: findings from a national population-based survey

Objective: This study formed part of the South African National HIV, Incidence, Behaviour and Communication (SABSSM) 2008 survey, which included questions assessing the extent of alcohol use and problem drinking among South Africans. Method: A multistage random population sample of 15 828 persons aged 15 or older (56.3% women) was included in the survey. Alcohol use was assessed using the Alcohol Use Identification Test (AUDIT). Tabulation of data for different age groups, geolocality, educational level, income, and population group produced the estimates and associated confidence intervals. The odds ratios for these variables in relation to hazardous or harmful drinking were also computed. Results: Current alcohol use was reported by 41.5% of the men and 17.1% of women. White men (69.8%) were most likely and Indian/Asian women (15.2%) least likely to be current drinkers. Urban residents (33.4 %) were more likely than rural dwellers (18.3%) to report current drinking. Risky or hazardous or harmful drinking was reported by 9%: 17% among men and 2.9% among women. In men, risky drinking was associated with: the 20-54 year age group; the Coloured population group; lower economic status; and lower education. Among women, risky drinking was associated with: urban residence; the Coloured population group; lower education; and higher income. Conclusion: An increase in current, binge drinking and hazardous or harmful drinking prevalence rates was observed from 2005 to 2008 in South Africa. Multilevel interventions are required to target high-risk drinkers and to create awareness in the general population of the problems associated with harmful drinking. Future prospective studies are needed to assess the impact of problem drinking.Key words: Alcohol use; Binge drinking; Hazardous or harmful drinking; Prevalence; National, population-based survey; South Afric

Decay Rate of Triaxially-Deformed Proton Emitters

The decay rate of a triaxially-deformed proton emitter is calculated in a particle-rotor model, which is based on a deformed Woods-Saxon potential and includes a deformed spin-orbit interaction. The wave function of the $I=7/2^{-}$ ground state of the deformed proton emitter $^{141}$Ho is obtained in the adiabatic limit, and a Green's function technique is used to calculate the decay rate and branching ratio to the first excited 2$^{+}$ state of the daughter nucleus. Only for values of the triaxial angle $\gamma$ $<5^{\circ}$ is good agreement obtained for both the total decay rate and the 2$^{+}$ branching ratio.Comment: 19 pages, 4 figure

How players exploit variability and regularity of game actions in female volleyball teams

Variability analysis has been used to understand how competitive constraints shape different behaviours in team sports. In this study, we analysed and compared variability of tactical performance indices in players within complex I at two different competitive levels in volleyball. We also examined whether variability was influenced by set type and period. Eight matches from the 2012 Olympics competition and from the Portuguese national league in the 2014–2015 season were analysed (1496 rallies). Variability of setting conditions, attack zone, attack tempo and block opposition was assessed using Shannon entropy measures. Magnitude-based inferences were used to analyse the practical significance of compared values of selected variables. Results showed differences between elite and national teams for all variables, which were co-adapted to the competitive constraints of set type and set periods. Elite teams exploited system stability in setting conditions and block opposition, but greater unpredictability in zone and tempo of attack. These findings suggest that uncertainty in attacking actions was a key factor that could only be achieved with greater performance stability in other game actions. Data suggested how coaches could help setters develop the capacity to play at faster tempos, diversifying attack zones, especially at critical moments in competition

An Ecological Dynamics perspective on Adventure Tourism

Traditional definitions for adventure tourism have focused on the adventure tourism activity or the adventure tourism environment. In these cases the activity is most often associated with risk and the environment associated with unfamiliarity and natural terrains. Critiques of these definitions have pointed out that this traditional perspective is limited. The risk focus is paradoxical as clients purchase adventure experiences involving risk and uncertainty, whereas tour operators must minimize the risk and emphasize safety. Additionally, adventure tourism can also take place in urban or man-made environments. Furthermore, the traditional definitions mostly ignore the lived experience of the adventure consumer. Individuals undertake adventure for a variety of reasons, including risk and thrills, health and well-being, connection to others and nature, recreational mastery, and personal development. We propose a nuanced conceptual understanding of adventure tourism within an ecological dynamics perspective that considers the relationship between the person, the adventure activity and the surrounding environment, and the recognition of affordances that support well-being. This theoretical approach provides a useful framework for operators and researchers that encourages a more personalized and meaningful experience for the tourist