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Summary A group of Brazilian leprosy patients and controls were genotyped for a CA-repeat microsatellite polymorphism within the interferon (IFN)-γ gene. A significantly higher frequency of alleles 5–7 was observed in this patient population, indicating that IFN-γ gene polymorphism may contribute to the course of leprosy post-infection. [ABSTRACT FROM AUTHOR]

Efforts to quantify net greenhouse gas emissions at the national scale, as required by the United Nations Framework Convention on ClimateChange, must include both industrial emissions and the net flux associated with the land base. In this study, data on current land use, rates of land-cover change, forest harvest levels, and wildfire extentwere analyzed under a common framework for three countries in order to compare net CO2-carbon flux, and to identify key research areas. In the Former Soviet Union (FSU) and the conterminous United States (US), the stand age-class distribution on the forested land and the rate of logging tended to. be the most important factors in the land-base flux, whereas in Brazil the rate of land-cover change and the vegetation regrowth in secondary forests on abandoned agricultural or grazing land were critical. The areas of greatest uncertainty for the FSU and US analyses related to the rates of woody debris and soil organic matter accumulation and to limitations in the age-class based inventory data available. In Brazil, the initial biomass in forests subject to deforestation, and the area of recovering secondary forest, were identified as important research issues. Continued database development, and close attention to methodologies for quantifying carbon flux, will be necessary if carbon budget assessments are to beof use to the policy community. [ABSTRACT FROM AUTHOR]

Terrestrial-carbon (C) pool sizes are of interest in relation to quantifying current sources and sinks of C, and evaluating the possibilities for future C sequestration or release by the biosphere. In this study, the C pools in the terrestrial ecosystems of the former SovietUnion (SUf), conterminous United States (USc) and Brazil were estimated for a nominal 1990 base year. Data sources included recent vegetation maps, resource inventories (particularly for forests), and published values for C densities (mass per unit area). Methodology varied by nation depending upon data availability but generally consisted of identifying a suitable land cover classification system, quantifying the area of each land cover type using traditional mapping approaches or satellite remote sensing, and assigning a mean C density to each cover type with separation by phytomass, litter plus coarse woody debris, and soil. Total organic C for the 3 geographic areas was estimated at 839 Pg (Pg = g x 1015) C in 1990, 38% of a literature-based estimate of the global terrestrial-C pool on an area representing 28% of the world's lands (excluding Antarctica). The soil C pool was the largest component in the SUf (84% of the total) and USc (76%) but not in Brazil (47%). Correspondingly, the proportion as phytomass was greatest in Brazil (48%) compared to the SUf (10%) and USc (17%). The forest land cover class contained by far the largest proportionof C among the land cover classes except in the SUf wherepeatlands were dominant with 37% of the total. The 2 largest C poolsisolated in this study are potentially long-term sources of C to theatmosphere: soil C in peatlands of SUf (212 Pg) which maybe lost via climate change, and phytomass C in the tropical-moist forests of Brazil (105 Pg) which may be lost via deforestation. [ABSTRACT FROM AUTHOR]

Abstract: Emerald, the green gem variety of beryl, is the third most valuable gemstone (after diamond and ruby). Although it is difficult to obtain accurate statistics, Colombia supplies most (an estimated 60%, worth more than $500,000,000 per year) of the world''s emeralds. However there is speculation that the emerald mines in Colombia are becoming depleted. Brazil currently accounts for approximately 10% of world emerald production. Emeralds have also been mined in Afghanistan, Australia, Austria, Bulgaria, China, India, Madagascar, Namibia, Nigeria, Pakistan, South Africa, Spain, Tanzania, the United States, and Zimbabwe. Because it is difficult to obtain accurate analyses of beryllium, most published analyses of beryl are renormalized on the basis of 18 oxygen and 3 Be atoms per formula unit. The color of emerald is due to trace amounts of chromium and/or vanadium replacing aluminum at the Y site; in most cases the Cr content is much greater than that of V. To achieve charge balance, the substitution of divalent cations at the Y site is coupled with the substitution of a monovalent cation for a vacancy at a channel site. Beryl is relatively rare because there is very little Be in the upper continental crust. Unusual geologic and geochemical conditions are required for Be and Cr and/or V to meet. In the classic model, Be-bearing pegmatites interact with Cr-bearing ultramafic or mafic rocks. However in the Colombian deposits there is no evidence of magmatic activity and it has been demonstrated that circulation processes within the host black shales were sufficient to form emerald. In addition, researchers are recognizing that regional metamorphism and tectonometamorphic processes such as shear zone formation may play a significant role in certain emerald deposits. A number of genetic classification schemes have been proposed for emerald deposits. Most are ambiguous when it comes to understanding the mechanisms and conditions that lead to the formation of an emerald deposit. Studies of individual emerald deposits show that in most cases a combination of mechanisms (magmatic, hydrothermal, and metamorphic) were needed to bring Be into contact with the chromophores. This suggests the need for a more flexible classification scheme based on mode of formation. Stable isotopes can be used to estimate the contribution of each mechanism in the formation of a particular deposit. Such estimates could perhaps be more precisely defined using trace element data, which should reflect the mode of formation. Emerald may be identified in the field by color, hardness, and form. It will tend to show up in stream sediment samples but because its specific gravity is relatively low, it will not concentrate in the heavy mineral fraction. In Colombia, structural geology, the sodium content of stream sediment samples, and the lithium, sodium, and lead contents of soil samples have all been used to find emerald occurrences. Exploration for gem beryl could result in the discovery of new occurrences of non-gem beryl or other Be minerals that could become new sources of Be and Be oxide. Future efforts should go towards creating a comprehensive data base of emerald compositions (including trace elements), determination of the role of metamorphism in the formation of some emerald deposits, improved classification schemes, and more effective exploration guidelines. [Copyright &y& Elsevier]

We investigated primary human herpesvirus-6 and -7 (HHV-6, HHV-7) infections as a cause of rashes incorrectly diagnosed as measles in Brazilian children. Sera from 124 patients, aged 4 months to 17 years, from the states of Rio de Janeiro and Espirito Santo, in whom measles, rubella and parvovirus B19 infections had been excluded, were studied using indirect immunofluorescence antibody avidity tests; 38 (31%) had evidence of primary HHV-6 and/or HHV-7 infections. Twenty four children had primary HHV-6 infection, either recent or coincident with the rash, and similarly 31 had primary HHV-7 infection. Remarkably, almost half (17) of primary infections were dual HHV-6 and HHV-7 infections with the majority, 12 (71%), in children less than 1 year old. HHV-7 infection occurred earlier than previously reported, perhaps due to socioeconomic and tropical conditions in this region of Brazil, and thus coincided with the HHV-6 infections. This study also highlights the difficulties of diagnosing a rash illness on clinical grounds alone.