[Review of] Shay Youngblood. The Big Mama Stories

Shay Youngblood learns how to tell stories from her many Big Mamas. The tales answer questions about her biological mother who is dead, what it means to be a woman, and how it feels to be black in Princeton, Georgia, prior to the civil rights movement. The voices of Big Mama, Miss Emma Lou, Aunt Mae and others leap off the page, and take readers on a journey into homes, on porches, and down the river fishing. Each story is a piece of a puzzle that adds to form a complete picture of the protagonist

Design and calibration of far-UV photometers for rocket use

Design and calibration of far UV photometer

Analog-to-digital conversion techniques for precision photometry

Three types of analog-to-digital converters are described: parallel, successive-approximation, and integrating. The functioning of comparators and sample-and-hold amplifiers is explained. Differential and integral linearity are defined, and good and bad examples are illustrated. The applicability and relative advantages of the three types of converters for precision astronomical photometric measurements are discussed. For most measurements, integral linearity is more important than differential linearity. Successive-approximation converters should be used with multielement solid state detectors because of their high speed, but dual slope integrating converters may be superior for use with single element solid state detectors where speed of digitization is not a factor. In all cases, the input signal should be tailored so that they occupy the upper part of the converter's dynamic range; this can be achieved by providing adjustable gain, or better by varying the integration time of the observation if possible

Search for R-parity Violating Decays of Supersymmetric Particles at LEP

Searches for pair-produced charginos, neutralinos and scalar fermions decaying via R-parity violating / /\' and /\'' couplings with the OPAL detector at LEP are presented at sqrt(s)=189 GeV. Partial updates using data up to the highest energies of LEP, sqrt(s)=209 GeV, are also given.Comment: 5 pages, 11 figures. To be published in the Proceedings of DPF2000, The Meeting of The Division of Particles and Fields of The American Physical Society, Columbus, Ohio, 9-12 August 2000, (Supplement of the International Journal of Modern Physics A (IJMP)

Urbanization without growth : a not-so-uncommon phenomenon

To find out why African countries'experience with urbanization and sustained growth appeared to differ from that of other countries, the authors investigated the determinants of urbanization across countries over 40 years. Rather than studying individuals'decisions to migrate, they relied on macroeconomic data and cross-country comparisons. A central hypothesis of their study: that individuals move (with varying degrees of ease) in response to economic incentives and opportunities. If location incentives are distorted, so is growth. The authors find that urbanization levels are closely correlated with levels of income. But urbanization continues even during periods of negative growth, carried by its own momentum, largely a function of the level of urbanization. From that viewpoint, Africa's urbanization without growth is not a puzzle. Factors other than income that help predict differences in levels of urbanization across countries include: a) income structure; b) education; c) rural-urban wage differentials; d) ethnic tensions; and e) civil disturbances. In addition, the relationship between economic incentives and urbanization is weaker in countries with fewer civil or political liberties. Factors other than initial urbanization level that help explain the speed of urbanization include: 1) The sector from which income growth is derived; 2) ethnic tensions; 3) civil disturbances and democracy (these two slow the pace of urbanization if all else is constant); 4) rural-urban wage differentials, whether they represent an urban bias or simply lower productivity in agriculture relative to other sectors. The weak relationship that this study shows between urbanization and traditionally accepted migration factors suggests that in Africa economists are overlooking part of the urbanization story. The fact that the informal sector appears to provide a significant source of income for urban migrants, coupled with the overlap between rural and urban activities, may shed light on the nature of urbanization in Africa.Banks&Banking Reform,National Urban Development Policies&Strategies,Urban Housing and Land Settlements,Public Health Promotion,Urban Services to the Poor,Urban Housing and Land Settlements,National Urban Development Policies&Strategies,Governance Indicators,Banks&Banking Reform,Urban Services to the Poor