Computational and theoretical aspects of a grain-boundary model at finite deformations

A model to describe the role of grain boundaries in the overall response of a polycrystalline material at small length scales subject to finite deformations is presented. Three alternative thermodynamically consistent plastic flow relations on the grain boundary are derived and compared using a series of numerical experiments. The numerical model is obtained by approximating the governing relations using the finite element method. In addition, the infinitesimal and finite deformation theories are compared, and the limitations of the former made clear

Has ‘Welfare Dependency’ Increased?

This paper uses the Panel Study of Income Dynamics from 1975 to 1992 to measure changes in the distribution of years of receipt of AFDC. The process generating the total number of years of welfare receipt is then disaggregated into four components: (1) the length of time until first birth, (2) the duration until a welfare spell begins, (3) the duration of a welfare spell, and (4) the duration until the woman re-enters the welfare system. Since much of the recent debate has focused on unwed teen mothers, we give special attention to this group. Finally, we focus on events that accompanied the end of welfare spells. We find no systematic evidence of increased dependency, either for all women or for women who had their first child as unwed teens. The stability of the overall measures of total time on welfare, however, reflects offsetting changes in the underlying processes. For example, the duration until first birth declined but there was no trend in the time between first birth and entry onto welfare. This holds for unwed teens as well as other women. Furthermore, we find that the duration of welfare spells declined for unwed teens but increased for others. Changes in events associated with entry onto welfare and exits from welfare also do not support the view that welfare recipients were less likely to use the labor market to change their welfare status.

Pro-poor growth: the evidence beyond income.

It is widely agreed that economic growth is necessary for reducing poverty. It is also well-established that poverty is multi-dimensional and not fully explained by income levels alone. Therefore, this paper attempts to fill a relative gap in the pro-poor growth literature by examining the impact of income growth on non-income poverty, particularly child mortality. The results confirm that although changes in per capita income matter for non-income poverty outcomes, they may not matter as much as for income poverty or as much as other factors, particularly in low-income countries. For developing countries, we find that a 1 per cent increase in income per capita is associated with a 0.3 per cent decline in the child mortality rate, declining to just a 0.1 per cent reduction for Sub-Saharan Africa. In contrast, a country‟s level of literacy appears to have a larger impact on non-income poverty with a 1 per cent decline in illiteracy associated with as much as a 0.5 per cent decline in child mortality in low-income countries. Our results suggest that pro-poor growth policies must be more sensitive to the constraints that exist in poorer countries that reduce the impact of economic growth on poverty

Computational and theoretical aspects of a grain-boundary model that accounts for grain misorientation and grain-boundary orientation

A detailed theoretical and numerical investigation of the infinitesimal single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008) "A theory of grain boundaries that accounts automatically for grain misorientation and grain-boundary orientation". Journal of the Mechanics and Physics of Solids 56 (2), 640-662, is performed. The governing equations and flow laws are recast in variational form. The associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. Various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. An alternative measure is also suggested. A series of three-dimensional numerical examples serve to elucidate the theory

Risk communication and generic preparedness: from agent-based to action-based planning - a conceptual framework

Responses to recent infectious disease outbreaks, such as to Influenza Pandemic 2009 and the on-going Ebola outbreak in West Africa, reveal the need for new and strengthened approaches to risk communication and governance. The article argues for a fundamental re-conceptualisation of current approaches to risk communication, preparedness planning and response. It calls for a reframing of the way we currently identify and respond to outbreaks around a set of core behaviour-based response patterns. This new model moves away from the current risk communication focus on a plethora of agent-specific threats to five generic response patterns that are based on socially relevant response activities such as 1) controlling vectors, 2) enhancing hygiene, 3) isolation of the sick, 4) protection of the well, and 5) systemic protection of people and their environments. Emphasis is placed on gaining relevant insights into the context specific needs of different communities related to these five patterns. Governance structures are then built and evaluated based on their capacity to collect, communicate, share and prepare the public to take appropriate action related to the five different patterns before, during and after an event. Reframing risk communication and preparedness approaches around a better understanding of the determinants of these general behavioural patterns in infectious control could strengthen infection control literacy, response competence and build resilience of both individuals and health systems to address future epidemics, pandemics and other public health threats

Earnings distribution, corporate governance and CEO pay

We investigate the relationship between earnings differentials and the pay of CEOs of 190 British companies between 1970 and 1990. We find that (i) changes in the differential between the 90th and 50th weekly earnings percentiles for non-manual adult male workers [90:50] explain changes in the level of real CEO salary and bonus in our sample of companies; (ii) changes in this differential also account for changes in the elasticity of CEO pay to firm size; (iii) a broader measure of earnings inequality does far worse than 90:50 at explaining changes in both the level and the firm size elasticity of CEO pay; (iv) fitting the model on data for 1970-1983 and predicting pay levels for the period starting with the widespread adoption of executive share option schemes in 1984, we find a structural break in the relationship between lower management pay differentials and the pay of the CEO. We conclude first that top executive pay prior to 1984 was a stable function of both firm size and earnings differentials lower on the administrative ladder, consistent with a hypothesis advanced by Herbert Simon in 1957; and second that the use of share options from 1984 onward represents not simply a change in the mode of top executive compensation, but a de -linking of the pay of top executives and that of their subordinates

The Problem of Defining Islam in Arampur

An annual religious procession makes its way along darkened brick-paved and packed-earth streets through the various neighbourhoods of Arampur, a village in Bihar, India. Young men chant formulaic slogans while ritually clashing in shows of weaponhandling. Women, men, and children stand in the night or sit on string beds outside their homes watching the lively action come and go on their otherwise non-eventful street. Occasionally they shout their support for the prancing adolescents. In this village with nearly equal numbers of Hindus and Muslims, is this procession Hindu or Islamic

Neutrino dimuon production and the dynamical determination of strange parton distributions

Utilizing recent neutrino dimuon production measurement from NuTeV the assumptions on the determination of the strangeness content of the nucleon within the dynamical approach to parton distributions are investigated. The data are found to be in good agreement with the predictions derived from our (GJR08) dynamical parton distributions, which have been generated entirely radiatively starting from vanishing strange input distributions at an optimally chosen low resolution scale. Further, the data induce an asymmetry in the strange sea which is found to be small and positive in agreement with previous results.Comment: 6 pages, 2 figure

Measurement of the running b-quark mass using e+e−→bbˉge^+e^- \to b\bar{b}g events

We have studied the determination of the running b-quark mass, $m_b(M_Z)$, using $Z^0$ decays into 3 or more hadronic jets. We calculated the ratio of $\geq3$-jet fractions in $e^+e^-\to b\bar{b}$ vs. $e^+e^-\to q_l\bar{q_l}$ ($q_l$ = u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted $m_b(M_Z)$ value. Our best estimate, taking correlations into account, is $m_b(M_Z) = 2.56 \pm 0.27 (stat.) ^{+0.28}_{-0.38} (syst.) ^{+0.49}_{-1.48} (theor.) GeV/c^2$.Comment: 22 pages (LaTeX), 1 Postscript figure. Version to appear in Phys. Lett. B. Several clarifying remarks added in the text, typos corrected, and theoretical results for very small masses added in the figur