Measures of Niche Overlap, II

An axiomatic basis for the construction of measures of niche overlap is analysed, and its implications are discussed, with particular reference to the more commonly used measures. A method of establishing that a measure of overlap complies with the axioms is put forward, making possible the construction of families of new measures. Certain extremal measures of overlap are also identifie

Measures of Niche Overlap, I

Many methods of measuring niche overlap have been proposed, such as those of Renkonen, Morisita, and Horn. In this paper, conditions are put forward which overlap indices should reasonably be expected to satisfy. A general description of a good index is given, which covers as special cases those of the well-known indices which satisfy all the conditions. A mixture of the Renkonen and van Belle & Ahmad indices is suggested, as it has many desirable properties. The problem of estimating overlap from data is discussed briefl

The triggering of MHD instabilities through photospheric footpoint motions

The results of 3D numerical simulations modelling the twisting of a coronal loop due to photospheric vortex motions are presented. The simulations are carried out using an initial purely axial field and an initial equilibrium configuration with twist, . The non-linear and resistive evolutions of the instability are followed. The magnetic field is twisted by the boundary motions into a loop which initially has boundary layers near the photospheric boundaries as has been suggested by previous work. The boundary motions increase the twist in the loop until it becomes unstable. For both cases the boundary twisting triggers the kink instability. In both cases a helical current structure wraps itself around the kinked central current. This current scales linearly with grid resolution indicating current sheet formation. For the cases studied 35-40% of the free magnetic energy is released. This is sufficient to explain the energy released in a compact loop flare

Public perceptions of a radioactively contaminated site: concerns, remediation preferences, and desired involvement.

A public attitudes survey was conducted in neighborhoods adjacent to a radioactively contaminated site whose remediation is now under the auspices of the U.S. Department of Energy's Formerly Utilized Sites Remedial Action Program (FUSRAP). The survey's purpose was to ascertain levels of actual and desired public involvement in the remediation process; to identify health, environmental, economic, and future land-use concerns associated with the site; and to solicit remediation strategy preferences. Surface water and groundwater contamination, desire for public involvement, and potential health risks were found to be the most highly ranked site concerns. Preferred remediation strategies included treatment of contaminated soil and excavation with off-site disposal. Among on-site remediation strategies, only institutional controls that leave the site undisturbed and do not require additional excavation of materials were viewed favorably. Cost of remediation appeared to influence remediation strategy preference; however, no strategy was viewed as a panacea. Respondents were also concerned with protecting future generations, better assessment of risks to health and the environment, and avoiding generation of additional contaminated materials

The archaeology of a landslide: Unravelling the Azores earthquake disaster of 1522 and its consequences

The multidisciplinary research described here shows how archaeologists can help reconstruct past seismic episodes and understand the subsequent relief operation, rehabilitation, and reconstruction processes. In October 1522, a major earthquake and landslide struck the then capital of the Azores, Vila Franca do Campo, 1500 km from the European mainland. Damage was extensive, destroying key monuments, affecting most of the inhabited area, and leaving few survivors among the early colonists. The results from twenty-six archaeological trenches, geological and geoarchaeological investigations, and documentary analysis are reviewed here. Distinctive archaeological deposits are identified and explained, using the high density of artefacts and the erosional contact between the landslide and the pre-1522 palaeosol to reconstruct the episode in detail

Numerical simulations of kink instability in line-tied coronal loops

The results from numerical simulations carried out using a new shock-capturing, Lagrangian-remap, 3D MHD code, Lare3d are presented. We study the evolution of the m=1 kink mode instability in a photospherically line-tied coronal loop that has no net axial current. During the non-linear evolution of the kink instability, large current concentrations develop in the neighbourhood of the infinite length mode rational surface. We investigate whether this strong current saturates at a finite value or whether scaling indicates current sheet formation. In particular, we consider the effect of the shear, defined by where is the fieldline twist of the loop, on the current concentration. We also include a non-uniform resistivity in the simulations and observe the amount of free magnetic energy released by magnetic reconnection

Comparing media and family predictors of alcohol use: a cohort study of US adolescents

Objective: To compare media/marketing exposures and family factors in predicting adolescent alcohol use. Design: Cohort study. Setting: Confidential telephone survey of adolescents in their homes. Participants: Representative sample of 6522 US adolescents, aged 10–14 years at baseline and surveyed four times over 2 years. Primary: outcome measure Time to alcohol onset and progression to binge drinking were assessed with two survival models. Predictors were movie alcohol exposure (MAE), ownership of alcohol-branded merchandise and characteristics of the family (parental alcohol use, home availability of alcohol and parenting). Covariates included sociodemographics, peer drinking and personality factors. Results: Over the study period, the prevalence of adolescent ever use and binge drinking increased from 11% to 25% and from 4% to 13%, respectively. At baseline, the median estimated MAE from a population of 532 movies was 4.5 h and 11% owned alcohol-branded merchandise at time 2. Parental alcohol use (greater than or equal to weekly) was reported by 23% and 29% of adolescents could obtain alcohol from home. Peer drinking, MAE, alcohol-branded merchandise, age and rebelliousness were associated with both alcohol onset and progression to binge drinking. The adjusted hazard ratios for alcohol onset and binge drinking transition for high versus low MAE exposure were 2.13 (95% CI 1.76 to 2.57) and 1.63 (1.20 to 2.21), respectively, and MAE accounted for 28% and 20% of these transitions, respectively. Characteristics of the family were associated with alcohol onset but not with progression. Conclusion: The results suggest that family focused interventions would have a larger impact on alcohol onset while limiting media and marketing exposure could help prevent both onset and progression

The Analysis of Injuries and Mortality Risks Level as a Result of Road Accident in Regions of the Central and Eastern Europe

In the article the analysis of the frequency, traumatism and mortality of road accidents has been carried out at the regional level for the countries of Central and Eastern Europe and has made it possible to draw conclusions regarding certain spatial features of the distribution of these indicators and on the nonrandom nature of the location of their values on maps of the CEE regions featured in the study. On the basis of methods of spatial statistics and econometrics we have demonstrated the existence of a spatial structure in the distribution of the risks and consequences of road accidents in the various regions. Cluster analysis has enabled us to distinguish uniform clusters of regions categorised by the risks, traumatism and mortality rates of road accidents. Based on an analysis of these indicators we have introduced the evaluation of an integrated safety level for regions of the countries of Central and Eastern Europe. This allows us to estimate the complex influence of the risks and their consequences road accidents on the level of safety for certain regions or groups of regions. The results of the research which has been conducted can be used for the improvement of national and regional programs of road and transport safety, and for the development of strategies and actions aimed at reducing the risks and consequences of road accidents in certain regions

Drawing the Line: How African, Caribbean and White British Women Live Out Psychologically Abusive Experiences

The final, definitive version of this paper has been published in Violence Against Women, 19 (9):1104-32, Sept 2013 by SAGE Publications Ltd, All rights reserved. © The Author(s) 2013. The online version of this article can be found at: http://vaw.sagepub.com/content/19/9/110