The Post-Apartheid Evolution of Earnings Inequality in South Africa, 1995-2004

This paper examines the trend in post-Apartheid earnings inequality in South Africa. By combining data sets, the paper is able to analyze the trend for the whole period 1995-2004. Earnings inequality rose sharply during 1995-1999 and then declined marginally, but remained high, during 2000-2004. A dramatic rise in unemployment was the driving force in exacerbating earnings inequality in the 1990s. Unemployment began to level off in the 2000s but remained at a high rate. An unprecedented influx of new entrants into the formal labour market in the 1990s put downward pressure on average real wages, affecting workers both in the middle of the distribution and toward the bottom. The growth of the South African economy has been neither rapid enough nor employment-intensive enough to absorb such a large influx of workers. Moreover, the economy?s greater openness to trade and financial flows appears to have left many workers behind, especially Africans, workers in low-skilled occupations, residents of rural areas in general and poor regions in particular. Earnings inequality remains high across groupings of workers differentiated by race, education and occupation although occupation has become a more important factor than the other two in the 2000s. Differentials across the mean earnings of workers classified by rural and urban residence and by province have also intensified. In the 1990s, inequalities within groupings of worker rose sharply and then moderated by the 2000s. While earnings differentials by race and the rural-urban divide also exacerbated inequality in the 1990s, they have been in modest decline since then. These changes in the dynamics of earnings inequality between the 1990s and 2000s pose new challenges for South African policymakers in their efforts to substantially reduce the Apartheid legacy of high inequality and poverty.South Africa, Income distribution, Earnings distribution, Inequality

Chronology: MSFC Space Station program, 1982 - present. Major events

The Marshall Space Flight Center (MSFC) maintains an active program to capture historical information and documentation on the MSFC's roles regarding Space Shuttle and Space Station. Marshall History Report 12, called Chronology: MSFC Space Station Program, 1982-Present, is presented. It contains synopses of major events listed according to the dates of their occurrence. Indices follow the synopses and provide additional data concerning the events listed. The Event Index provides a brief listing of all the events without synopses. The Element Index lists the specific elements of the Space Station Program under consideration in the events. The Location Index lists the locations where the events took place. The indices and synopses may be cross-referenced by using dates

Criterion for purely elastic Taylor-Couette instability in the flows of shear-banding fluids

In the past twenty years, shear-banding flows have been probed by various techniques, such as rheometry, velocimetry and flow birefringence. In micellar solutions, many of the data collected exhibit unexplained spatio-temporal fluctuations. Recently, it has been suggested that those fluctuations originate from a purely elastic instability of the flow. In cylindrical Couette geometry, the instability is reminiscent of the Taylor-like instability observed in viscoelastic polymer solutions. In this letter, we describe how the criterion for purely elastic Taylor-Couette instability should be adapted to shear-banding flows. We derive three categories of shear-banding flows with curved streamlines, depending on their stability.Comment: 6 pages, 3 figure

Potential "ways of thinking" about the shear-banding phenomenon

Shear-banding is a curious but ubiquitous phenomenon occurring in soft matter. The phenomenological similarities between the shear-banding transition and phase transitions has pushed some researchers to adopt a 'thermodynamical' approach, in opposition to the more classical 'mechanical' approach to fluid flows. In this heuristic review, we describe why the apparent dichotomy between those approaches has slowly faded away over the years. To support our discussion, we give an overview of different interpretations of a single equation, the diffusive Johnson-Segalman (dJS) equation, in the context of shear-banding. We restrict ourselves to dJS, but we show that the equation can be written in various equivalent forms usually associated with opposite approaches. We first review briefly the origin of the dJS model and its initial rheological interpretation in the context of shear-banding. Then we describe the analogy between dJS and reaction-diffusion equations. In the case of anisotropic diffusion, we show how the dJS governing equations for steady shear flow are analogous to the equations of the dynamics of a particle in a quartic potential. Going beyond the existing literature, we then draw on the Lagrangian formalism to describe how the boundary conditions can have a key impact on the banding state. Finally, we reinterpret the dJS equation again and we show that a rigorous effective free energy can be constructed, in the spirit of early thermodynamic interpretations or in terms of more recent approaches exploiting the language of irreversible thermodynamics.Comment: 14 pages, 6 figures, tutorial revie

Bubble kinematics in a sheared foam

We characterize the kinematics of bubbles in a sheared two-dimensional foam using statistical measures. We consider the distributions of both bubble velocities and displacements. The results are discussed in the context of the expected behavior for a thermal system and simulations of the bubble model. There is general agreement between the experiments and the simulation, but notable differences in the velocity distributions point to interesting elements of the sheared foam not captured by prevalent models

Elastic turbulence in shear banding wormlike micelles

We study the dynamics of the Taylor-Couette flow of shear banding wormlike micelles. We focus on the high shear rate branch of the flow curve and show that for sufficiently high Weissenberg numbers, this branch becomes unstable. This instability is strongly sub-critical and is associated with a shear stress jump. We find that this increase of the flow resistance is related to the nucleation of turbulence. The flow pattern shows similarities with the elastic turbulence, so far only observed for polymer solutions. The unstable character of this branch led us to propose a scenario that could account for the recent observations of Taylor-like vortices during the shear banding flow of wormlike micelles

Organizational downsizing: Constraining, cloning, learning

While downsizing rages through the U.S. economy, there is a great deal of uncertainty about its bottom-line effects. This uncertainty raises questions about why corporations have been so eager to engage in downsizing. In this article, we propose an answer to these questions. Three social forces, which we call constraining, cloning and learning, frequently provide a major impetus for downsizing. We describe these forces, and point out conditions that lead to the adoption of downsizing without due regard for its mixed consequences. We suggest methods to improve executives\u27 downsizing decision routines ... methods that should enhance the chances of achieving intended benefits