Individual and couple decision behavior under risk: evidence on the dynamics of power balance

This article reports results of an experiment designed to analyze the link between risky decisions made by couples and risky decisions made separately by each spouse. We estimate both the spouses and the couples' degrees of risk aversion, we assess how the risk preferences of the two spouses aggregate when they make risky decisions, and we shed light on the dynamics of the decision process that takes place when couples make risky decisions. We find that, far from being fixed, the balance of power within the household is malleable. In most couples, men have, initially, more decision-making power than women but women who ultimately implement the joint decisions gain more and more power over the course of decision making.

Spatial Heterogeneity and Kinetic Regulation of Arsenic Dynamics in Mangrove Sediments: The Sundarbans, Bangladesh

The biogeochemistry of arsenic (As) in sediments is regulated by multiple factors such as particle size, dissolved organic matter (DOM), iron mobilization, and sediment binding characteristics, among others. Understanding the heterogeneity of factors affecting As deposition and the kinetics of mobilization, both horizontally and vertically, across sediment depositional environments was investigated in Sundarban mangrove ecosystems, Bengal Delta, Bangladesh. Sediment cores were collected from 3 different Sundarbans locations and As concentration down the profiles were found to be more associated with elevated Fe and Mn than with organic matter (OM). At one site chosen for field monitoring, sediment cores, pore and surface water, and in situ diffusive gradients in thin films (DGT) measurements (which were used to model As sediment pore-water concentrations and resupply from the solid phase) were sampled from four different subhabitats. Coarse-textured riverbank sediment porewaters were high in As, but with a limited resupply of As from the solid phase compared to fine-textured and high organic matter content forest floor sediments, where porewater As was low, but with much higher As resupply. Depositional environment (overbank verses forest floor) and biological activity (input of OM from forest biomass) considerably affected As dynamics over very short spatial distances in the mosaic of microhabitats that constitute a mangrove ecosystem.

The dynamics of arsenic in four paddy fields in the Bengal delta

Irrigation with arsenic contaminated groundwater in the Bengal Delta may lead to As accumulation in the soil and rice grain. The dynamics of As concentration and speciation in paddy fields during dry season (boro) rice cultivation were investigated at 4 sites in Bangladesh and West Bengal, India. Three sites which were irrigated with high As groundwater had elevated As concentrations in the soils, showing a significant gradient from the irrigation inlet across the field. Arsenic concentration and speciation in soil pore water varied temporally and spatially; higher As concentrations were associated with an increasing percentage of arsenite, indicating a reductive mobilization. Concentrations of As in rice grain varied by 2-7 fold within individual fields and were poorly related with the soil As concentration. A field site employing alternating flooded-dry irrigation produced the lowest range of grain As concentration, suggesting a lower soil As availability caused by periodic aerobic conditions.

PCB congener dynamics in a heavily industrialized river catchment

PCB congener concentrations in the water column of a highly industrialized river catchment, the Aire/Calder, in N.E. England were determined weekly on a routine basis, and 2 hourly through selected high flow (flood) events. Bed, suspended and floodplain sediment PCB congener concentrations were also determined along transects of the rivers investigated. Weekly monitoring revealed that the sum of 11 quantified (Sigma11) PCBs rose in concentration by two orders of magnitude during late summer compared to their winter minimum values. This rise was concurrent with sustained periods of low flow. SigmaPCB concentrations were rapidly diluted during high flow (flood) events. Suspended sediment was, on average, 13 times more contaminated with PCBs than bed sediment, with means of 4.0 and 53.8 ng/g, respectively, while floodplain samples had an intermediate concentration of 29.8 ng/g. Principle components analysis (PCA) of congener profiles showed that all three sediment types were similar, but that congener profiles differed considerably between sediment and whole-water samples. There was no change in the percentage contribution of individual PCB congeners apparent from weekly whole-water monitoring. However, the congener pattern in whole-waters changed systematically during high flow events. PCA showed that whole-water samples collected during high flow events had progressively more sediment characteristics, and then returned to whole-water characteristics on cessation of the event. The PCA evidence, dilution of PCB concentrations during events, and suspended sediments more contaminated than bed sediments, indicate that the major sources of PCBs in this catchment are current inputs from sewage treatment works, rather than remobilization of bed sediments.

A complete analytic theory for structure and dynamics of populations and communities spanning wide ranges in body size

The prediction and management of ecosystem responses to global environmental change would profit from a clearer understanding of the mechanisms determining the structure and dynamics of ecological communities. The analytic theory presented here develops a causally closed picture for the mechanisms controlling community and population size structure, in particular community size spectra, and their dynamic responses to perturbations, with emphasis on marine ecosystems. Important implications are summarised in non-technical form. These include the identification of three different responses of community size spectra to size-specific pressures (of which one is the classical trophic cascade), an explanation for the observed slow recovery of fish communities from exploitation, and clarification of the mechanism controlling predation mortality rates. The theory builds on a community model that describes trophic interactions among size-structured populations and explicitly represents the full life cycles of species. An approximate time-dependent analytic solution of the model is obtained by coarse graining over maturation body sizes to obtain a simple description of the model steady state, linearising near the steady state, and then eliminating intraspecific size structure by means of the quasi-neutral approximation. The result is a convolution equation for trophic interactions among species of different maturation body sizes, which is solved analytically using a novel technique based on a multiscale expansion.

Social Class Variation in Risk: A Comparative Analysis of the Dynamics of Economic Vulnerability

A joint concern with multidimensionality and dynamics is a defining feature of the pervasive use of the terminology of social exclusion in the European Union. The notion of social exclusion focuses attention on economic vulnerability in the sense of exposure to risk and uncertainty. Sociological concern with these issues has been associated with the thesis that risk and uncertainty have become more pervasive and extend substantially beyond the working class. This paper combines features of recent approaches to statistical modelling of poverty dynamics and multidimensional deprivation in order to develop our understanding of the dynamics of economic vulnerability. An analysis involving nine countries and covering the first five waves of the European Community Household Panel shows that, across nations and time, it is possible to identify an economically vulnerable class. This class is characterized by heightened risk of falling below a critical resource level, exposure to material deprivation and experience of subjective economic stress. Cross-national differentials in persistence of vulnerability are wider than in the case of income poverty and less affected by measurement error. Economic vulnerability profiles vary across welfare regimes in a manner broadly consistent with our expectations. Variation in the impact of social class within and across countries provides no support for the argument that its role in structuring such risk has become much less important. Our findings suggest that it is possible to accept the importance of the emergence of new forms of social risk and acknowledge the significance of efforts to develop welfare states policies involving a shift of opportunities and decision making on to individuals without accepting the 'death of social class' thesis.

Current-induced atomic dynamics, instabilities, and Raman signals: Quasiclassical Langevin equation approach

We derive and employ a semiclassical Langevin equation obtained from path integrals to describe the ionic dynamics of a molecular junction in the presence of electrical current. The electronic environment serves as an effective nonequilibrium bath. The bath results in random forces describing Joule heating, current-induced forces including the nonconservative wind force, dissipative frictional forces, and an effective Lorentz-type force due to the Berry phase of the nonequilibrium electrons. Using a generic two-level molecular model, we highlight the importance of both current-induced forces and Joule heating for the stability of the system. We compare the impact of the different forces, and the wide-band approximation for the electronic structure on our result. We examine the current-induced instabilities (excitation of runaway "waterwheel" modes) and investigate the signature of these in the Raman signals.

Moving in and out of poverty - The impact of welfare regimes on poverty dynamics in the EU

Although many of the debates around social exclusion and cumulative disadvantage relate to processes that occur across time, there has been relatively little research into poverty dynamics except in a few notable countries such as Britain, the USA and Germany. This neglect is almost entirely because of the absence of comparative longitudinal data on income for other countries, but it is regrettable given the central importance of this area. By studying poverty dynamics we not only get a better insight into the processes leading to patterns of disadvantage and inequality, but we can also understand better the influence of different welfare state regimes on the social risks experienced by different types of individuals and households. The extent to which different national contexts protect their citizens from poverty persistence, or vary in the factors leading to poverty persistence, tells us a great deal about the workings of their socioeconomic systems and welfare regimes.

In this article we use the recent availability of five waves of the European Community Household Panel Survey to outline the nature of poverty persistence and poverty dynamics across a large number of countries. In doing so we ask three important questions. First, is poverty a more common experience when viewed longitudinally rather than cross-sectionally, and how is this affected by the income poverty line used? Second, can we identify a tendency toward poverty persistence, and does this vary in its extent across countries? Third and lastly, what types of events are more likely to lead to entry into and exit from poverty, and does the importance of these events differ between countries? The article shows that the experience of poverty is far wider than is appreciated from cross-sectional data, and also tends to be more concentrated on a particular population than would be expected from cross-sectional rates. Moreover, the pattern of poverty persistence is congruent with welfare regime theory. The importance of country institutions and welfare regimes is also underlined by the finding that social welfare and market incomes play different roles in poverty transitions across countries, and that Southern European, or residualist, welfare regimes focus poverty risks on the experience of the household's primary earner to a far greater extent than Northern European welfare states do.

Comparing poverty and deprivation dynamics:Issues of reliability and validity

In this paper we seek to establish if earlier findings relating to the relationship between income poverty persistence and deprivation persistence could be due to a failure to take measurement error into account. To address this question, we apply a model of dynamics incorporating structural and error components. Our analysis shows a general similarity between latent poverty and deprivation dynamics. In both cases we substantially over-estimate the probability of exiting from poverty or deprivation. We observe a striking similarity across dimensions for both observed and latent outcomes. In both cases levels of poverty and deprivation persistence are higher for the latent case. However, there is no evidence that earlier results relating to the differences in the determinants of poverty and deprivation persistence are a consequence of differential patterns of reliability. Taking measurement error into account seems more likely to accentuate rather than diminish the contrasts highlighted by earlier research. Since longitudinal differences relating to poverty and deprivation cannot be accounted for by measurement error, it seems that we must accept that we are confronted with issues relating to validity rather than reliability. Even where we measure these dimensions over reasonable periods of time and allow for measurement error, they continue to tap relatively distinct phenomenon. Thus, if measures of persistent poverty are to constitute an important component of EU social indicators, a strong case can be made for including parallel measures of deprivation persistence and continuing to explore the relationship between them. © Springer Science+Business Media, Inc. 2006.

Dynamics of Self-Generated, Large Amplitude Magnetic Fields Following High-Intensity Laser Matter Interaction

The dynamics of magnetic fields with an amplitude of several tens of megagauss, generated at both sides of a solid target irradiated with a high-intensity (~1019W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets. © 2012 American Physical Society.