Last Generation (last + generation)

Distribution by Scientific Domains

Selected Abstracts

Transformation of haematite and Al-poor goethite to Al-rich goethite and associated yellowing in a ferralitic clay soil profile of the middle Amazon Basin (Manaus, Brazil)

E. Fritsch
Summary The red and yellow colours of ferralitic soils in the tropics have for long intrigued pedologists. We have investigated the upward yellowing in a 10-m thick profile representative of the Ferralsols of the plateaux of the Manaus region of Brazil. We determined changes in the nature and crystal chemistry of their Fe oxides by optical and Mössbauer spectroscopy as well as Rietveld refinement of X-ray diffraction patterns. We attribute the upward yellowing of the soil to a progressive transformation of the Fe oxides at nearly invariant iron contents. Aluminium in contrast is strongly mobilized in the uppermost clay-depleted topsoil where there is preferential dissolution of kaolinite and crystallization of gibbsite. Haematite decreases from 35 to 10% of the Fe oxides from the bottom to the top of the profile and the particles become smaller (75,10 nm). Its Al for Fe-substitution remains almost unchanged (10,15 mol %). The average Al-substitution rate of goethite increases from 25 to 33 mol %, and its mean crystal diameter remains in the range 20,40 nm. The proportion of Al-rich goethite (33 mol %) increases at the expense of less Al-substituted Fe oxides (haematite and goethite). This conversion with restricted transfer of iron means that the amount of Al stored in Fe oxides gradually increases. Kaolinite, haematite and Al-poor goethite are thus witnesses of earlier stages of ferralitization of the soil. In contrast, Al-rich goethite and gibbsite initiate the alitization (or bauxitization) of the soil. They correspond to the last generation of soil minerals, which most likely reflects the present-day weathering conditions. The progressive replacement of kaolinite, haematite and Al-poor goethite by new generations of Al-rich goethite and gibbsite attests to greater activities of water and aluminium and smaller activity of aqueous silica in the topsoil than in the subsoil. We interpret this as a consequence of longer periods of wetting in the topsoil that could result from soil aging, more humid climate or both. [source]

Social Polarization and the Politics of Low Income Mortgage Lending in the United States

Jason Hackworth
ABSTRACT The structured inequalities of capital investment and disinvestment are prominent themes in critical urban and regional research, but many accounts portray ,capital' as a global, faceless and placeless abstraction operating according to a hidden, unitary logic. Sweeping political-economic shifts in the last generation demonstrate that capital may shape urban and regional processes in many different ways, and each of these manifestations creates distinct constraints and opportunities. In this paper, we analyze a new institutional configuration in the USA that is reshaping access to wealth among the poor , a policy ,consensus' to expand home-ownership among long-excluded populations. This shift has opened access to some low- and moderate-income households, and racial and ethnic minorities, but the necessary corollary is a greater polarization between those who are able to own and those who are not. We provide a critical analysis of these changes, drawing on national housing finance statistics as well as a multivariate analysis of differences between owners and renters in the 1990s in New York City. As home-ownership strengthens its role as a privatized form of stealth urban and housing policy in the USA, its continued expansion drives a corresponding reconstruction of its value for different groups, and inscribes a sharper axis of property-rights inequalities among owners and renters in the working classes. [source]

Executions, Deterrence, and Homicide: A Tale of Two Cities

Franklin E. Zimring
We compare homicide rates in two quite similar cities with vastly different execution risks. Singapore had an execution rate close to one per million per year until an explosive 20-fold increase in 1994,1995 and 1996 to a level that we show was probably the highest in the world. Then, over the next 11 years, Singapore executions dropped by about 95 percent. Hong Kong, by contrast, had no executions at all during the last generation and abolished capital punishment in 1993. Homicide levels and trends are remarkably similar in these two cities over the 35 years after 1973, with neither the surge in Singapore executions nor the more recent steep drop producing any differential impact. By comparing two closely matched places with huge contrasts in actual execution but no differences in homicide trends, we have generated a unique test of the exuberant claims of deterrence that have been produced over the past decade in the United States. [source]

Legal Change and Gender Inequality: Changes in Muslim Family Law in India

LAW & SOCIAL INQUIRY, Issue 3 2008
Narendra Subramanian
Group-specific family laws are said to provide women fewer rights and impede policy change. India's family law systems specific to religious groups underwent important gender-equalizing changes over the last generation. The changes in the laws of the religious minorities were unexpected, as conservative elites had considerable indirect influence over these laws. Policy elites changed minority law only if they found credible justification for change in group laws, group norms, and group initiatives, not only in constitutional rights and transnational human rights law. Muslim alimony and divorce laws were changed on this basis, giving women more rights without abandoning cultural accommodation. Legal mobilization and the outlook of policy makers,specifically their approach to regulating family life, their understanding of group norms, and their normative vision of family life,shaped the major changes in Indian Muslim law. More gender-equalizing legal changes are possible based on the same sources. [source]

Including an additional systematic environmental effect within a generation in an evaluation model improves accuracy of prediction of breeding values in a closed herd of pigs

Masahiro SATOH
ABSTRACT The present study evaluated the advantage of mixed-model techniques over a selection index under different magnitudes of an additional systematic environmental effect (ASEE) in terms of accuracy of prediction and expected genetic gain. The data attempted to simulate a closed herd in a pig breeding program. The base population (G0) consisted of 10 males and 50 females. Six generations (G0 to G5) were selected by using a selection index of three traits without overlapping. Additional systematic environmental constants with four levels in a generation were assigned from a uniform distribution at different ranges. Breeding values of animals in the last generation (G5) were estimated on the basis of an index of individual phenotype (SI-U), SI-U adjusted for ASEE using a least-squares mean (SI-A), best linear unbiased prediction using an animal model excluding ASEE (AM-E), and an animal model including ASEE (AM-I). Accuracy of prediction and expected genetic gain were larger by the animal model than by the selection index, even if heritability of the traits selected was high and ASEE was set to zero. When ASEE was zero, the accuracy of prediction and expected genetic gain given by SI-U and AM-I were similar to those given by SI-A and AM-E, respectively. However, the differences in accuracy and expected gain between SI-U and AI-A and between AM-I and AM-E increased as the range of ASEE increased. It was concluded that selection based on an animal model was more effective than index selection, even if the herd environment was uniform and traits with high heritability were selected, and that it should be always included in an evaluation model, however slight any systematic environmental effect may be in a closed herd. [source]

Spermatogonia and spermatocyte ultrastructure in Hoplias malabaricus (Teleostei, Characiformes: Erythrinidae)

José Nazareno Cunha Negrão
Abstract The Hoplias malabaricus primary spermatogonium shows a large nucleus, central nucleolus, and low electron-dense cytoplasm containing nuages. In cysts, they undergo several mitotic divisions with incomplete cytokinesis, giving rise to secondary spermatogonia. These are smaller than the primary spermatogonia and their nuclei have one or two eccentric nucleoli. Spermatocytes I can be identified by the presence of synaptonemal complexes. Spermatocytes II are smaller than spermatocytes I, displaying roughly compacted chromatin. All these cell types remain interconnected by thick-walled intercellular bridges, which have membranous reinforcements during mitosis and meiosis. These cell types show a well-developed endomembranous system, one of the centrioles anchored to the plasma membrane and small nuages. Their mitochondria are large and circular, with few cristae. In the last generations of spermatogonia, the mitochondria are smaller, elongate and have more cristae. In the spermatocytes, the mitochondria are small and round. Similarities found in relation to germ cells of other teleosts are discussed. [source]