The distribution of wages and employment in rural Botswana

African Studies Center Working Paper No. 4

Toxic releases by manufacturing : world patterns and trade policies

Little evidence exists on the distribution across countries of toxic releases by manufacturing, or on how those patterns change through time. A number of studies have asked whether environmental controls imposed in the industrialized economies are diverting investments in pollution-intensive activities offshore. These studies reach a broad negative conclusion: direct investment does not appear to be stimulated by such regulation, in part because the cost of emission controls is generally a tiny fraction of operating costs. But direct investment reflects only part of what may be happening to world production patterns. Technology transfers may occur with no simultaneous direct investment, and production may readily shift toward a different global distribution without either direct investment or technology transfer. The author presents the evidence on the world distribution of manufacturing production according to pollution density - using data from the World Bank Industrial Pollution Projections Team. He then examines the validity of the claim that free trade would result in greater and more rapid environmental degradation for developing countries. He finds that: (1) The onus is on the higher-income countries to contain the emissions of their increasingly pollution-oriented mix of manufacturing industries. (2) The global trend has been toward an increasingly emission-intensive pattern of production, in relation to both manufacturing and to GDP. This trend has been remarkably constant over three decades and shows no signs of slowing. (3) The upward trend in emission-intensity of manufacturing production has been faster among lower-income nations. If pollution restraints on given industies are progressing more rapidly among the wealthier countries, this disparity would be even sharper than the Bank data suggest. Developing countries that produce coal, crude oil, or natural gas also have more pollution-intensive manufacturing sectors, based on the availability of those raw materials. It may be doubted that fostering such industries always reflects a comparative advantage. Petrochemical industries in the coal-oil-gas-producing countries are often substantially protected or subsidized. Among all developing countries, import protection stimulates a larger chemicals industry and thus more emission-intensive manufacturing. One might guess that less protection of local industrial chemical industries would decrease the pollution-intensity of the developing countries'industry. But merely relocating firms that emit globally damaging toxins clearly misses the point.Environmental Economics&Policies,Energy and Environment,Economic Theory&Research,Water and Industry,Carbon Policy and Trading

The distribution and efficiency of crop production in tribal areas of Botswana

African Studies Center Working Paper No. 4

Economic development, environmental regulation, and the international migration of toxic industrial pollution : 1960-88

Several previous studies have asked whether environmental controls imposed in the industrial economies are diverting investments in pollution-intensive activities off-shore. Broadly, these studies conclude that direct investment does not appear to be stimulated by such regulations, partly because the cost of emission controls is generally a tiny fraction of operating costs. Yet direct investment reflects only part of what may be happening to world production patterns. Technology transfers may occur with no simultaneous direct investments, and production may readily shift toward a different global distribution without either direct investment or technology transfer. The authors attempt a general test of the displacement hypothesis, developing time series estimates of manufacturing pollution intensity for a large sample of developed and developing countries between 1960 and 1988. Among their conclusions: As a result of shifts in industrial composition, total manufacturing emissions relative to GDP grow faster than GDP at lower levels of per capita income and slower than GDP at higher levels of income. This happens because manufacturing has a declining share of GDP at higher income levels, not because of any shift toward a cleaner mix of manufacturing activities. The more rapidly growing high-income countries have actually enjoyed negative growth in toxic intensity of their manufacturing mix. Stricter regulation of pollution-intensive production in the OECD countries appears to have led to significant locational displacement, with consequent acceleration of industrial pollution intensity in developing countries. The poorest economies seem to have the highest growth in toxic intensity. One cannot, of course, be certain of the causal connection. Pollution intensity has grown most rapidly in developing economies that are relatively closed to world market forces. Relatively closed, fast-growing economies experienced rapid structural transitions toward greater toxic intensity. The opposite seems to have been true for more open economies.Environmental Economics&Policies,Economic Theory&Research,Energy and Environment,Water and Industry,Health Monitoring&Evaluation

International migration: economic causes, consequences, evaluation, and policies

African Studies Center Working Paper No. 21The 70's have witnessed a number of events which are again focussing attention of economists on international migration: the dramatic emergence of the Middle East labor markets is affecting the economies of the low income Middle Eastern nations and of South Asia on a large scale; the world recession with its associated unemployment in North America and Western Europe has stimulated increased conservatism with regard to immigration policy; increasing tension in Southern Africa has raised interest in the continuing role of South Africa as a major employer of workers from neighboring countries; and the longstanding rhetoric against the brain-drain from poorer nations has persisted. The present paper attempts to provide a synopsis of some of the economic issues pertinent to the consideration of these phenomena, and is organized into four main sections. Section I deliberates some of the causes of international migration, drawing in part on the literature on internal migration. Section II then proceeds to consider some of the economic consequences of international migration. This section is subdivided into two parts: the first dealing with migration in promoting global and national productive efficiency -- a subject of much attention in economic theory; the second addressing some of the questions on international and internal distribution of incomes. Section III deals with an area in which almost no literature exists: building on the results of the previous sections, a framework for considering cost-benefit evaluation studies of international migration is briefly outlined. Finally, the fourth section discusses some of the policy instruments used today, or which might be adopted, for promoting, discouraging or changing the nature of international migration a discussion based on the summary of causes and consequences, and ultimately requiring some form of evaluation prior to implementation

Experimental Studies of Effects of Geometry on Drying Rate and Properties of Ginger (Zingiber officinale Rosc.) with Solar-hybrid Dryer

Poor drying and processing methods employed by Nigerian farmers have led to loss of quality of dried ginger produced. Therefore, there is need to improve the drying and processing methods so that the quality of the products will be improved. To achieve this, a natural convection solar dryer was designed and constructed to dry ginger slices in different geometries. A 3 kg capacity hybrid dryer which was solar and biomass fueled was designed. The ginger samples were grouped into peeled and unpeeled. The specimens (peeled and unpeeled) were cut into cylindrical (Ø 0.2 m, thickness 0.008 m) and rectangular (0.03 x 0.025 m, thickness 0.008 m) shapes and 2.7 kg each were dried using open air, solar assisted and hybrid dryer. The initial and final moisture contents considered were 82.3% and 10% (wet basis), respectively. The average ambient conditions were 30 ºC air temperature and 15% relative humidity with daily global solar radiation incident on horizontal surface of about 20MJ/m2 /day. The weather conditions considered are of Ogbomoso, Nigeria. A prototype of the dryer is so designed and constructed that has a maximum collector area of 1.03m2. The percentage essential oil retention of cylindrical was higher than that of rectangular. Keywords: Solar biomass dryer, Ginger, geometry, drying, essential oil Radiatio

Migration amongst the Batswana

African Studies Center Working Paper No. 70INTRODUCTION The hypothesis presented in Todaro (1969), that the likelihood of finding work in town influences the rate of rural-urban migration, now enjoys the status of a received doctrine. Assuming potential migrants indeed respond to this employment probability, the model of Harris and Todaro (1970) demonstrates that, in certain parametric ranges, urban job creation may actually exacerbate unemployment and even reduce national product. This result has had considerable influence on policy formulation in LDC, by emphasizing that, in the urban sector, the social opportunity cost of labor may not be insignificant despite burgeoning unemployment. Yet neither the Todaro hypothesis nor prevalence of the Harris-Todaro parametric range has been adequately, empirically explored. Many estimates of macro migration equations do exist, normally relating the proportion of population migrating to average wages in differing locations and occasionally to average population characteristics. But in Lucas (1975), I show that the popular nonlinear specification of such macro functions may well display serious specification error bias; a nonlinear function of the aggregate variables is not simply the average of underlying micro migration decisions related to the disaggregated variables. Thus, although a few estimates of macro migration equations have also incorporated average unemployment rates, usually in developed country contexts and with mixed results, these analyses are at best very circumscribed tests of the Todaro and Harris-Todaro theories. [TRUNCATED

Mines and migrants in South Africa

African Studies Center Working Paper No. 106Between 1971 and 1978 wages of more than half a million nonwhite laborers in the South African mines tripled in real terms. In the same period, the nonwhites employed in the mines switched from being 62 percent foreign to 62 percent domestic. These changes followed a period -- from 1911 to 1971 -during which real wages of black gold miners did not rise, and terminated almost a century of reliance on foreign labor "reserves" for the majority of such labor. These dramatic events are examined here in the context of an econometric model of the demand for labor by the South African mining sector from 1946 to 1980. This affords an unusual opportunity to study the demand side of a market for internal and international migrants, in a society where racial discrimination is formalized in- the apartheid system, where powerful mining houses wield potential monopsony power, and political factors in the region are major determinants of economic behavior. To comprehend the derived demand for workers in this sector, it is essential to outline at least certain aspects of the industry's organization and that of the market for labor. This is undertaken in section I, section II develops a stylized model, which is then estimated, from data described in III, for the gold, diamond, coal and other minerals sectors separately in section IV

The distribution of transit durations for Kepler planet candidates and implications for their orbital eccentricities

‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyDoppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If we assume a Rayleigh eccentricity distribution for Kepler planet candidates, then we find best fits with a mean eccentricity of 0.1-0.25 for host stars with T ≤ 5100 K. We compare the transit duration distribution for different subsets of Kepler planet candidates and discuss tentative trends with planetary radius and multiplicity. High-precision spectroscopic follow-up observations for a large sample of host stars will be required to confirm which trends are real and which are the results of systematic errors in stellar radii. Finally, we identify planet candidates that must be eccentric or have a significantly underestimated stellar radius.Peer reviewedFinal Accepted Versio