The Grenvillian assembly of Rodinia: Timing of accretion on the western margin of the Kalahari (Kaapvaal) Craton

During the Grenvillian assembly of Rodinia, the Namaqua-Natal Metamorphic Province (NNMP) was formed as a result of the convergence of the Laurentia and Kalahari cratons. A detailed model for this accretion along the southeastern margin of the Kalahari Craton has been established, but the tectonic history of the NNMP along the western margin of the Kalahari Craton has remained highly controversial. U-Pb SHRIMP zircon age dating of gneiss in the Kakamas Domain of the NNMP, as well as U-Pb SHRIMP age dating of detrital zircons and Ar-40/Ar-39 dating of metamorphic muscovite from sediments overlying the gneiss, confirms the presence of at least two separate events during the Namaqua-Natal Orogeny at similar to 1166 Ma and 1116 Ma. These events occurred after the Areachap Terrane was accreted onto the western margin of the Proto-Kalahari Craton during the Kheis Orogeny. Ar-40/Ar-39 ages derived from metamorphic muscovite formed in the metasediments of the Kheis terrane does not provide evidence for the timing of the Kheis Orogeny but suggests that it most likely only occurred after similar to 1300 Ma and not at 1800 Ma as commonly accepted. A U-Pb concordia age of similar to 1166 Ma was derived from granitic gneiss in the Kakamas Domain of the Bushmanland Subprovince, possibly reflecting subduction and the initiation of continent-continent collision between the Proto-Kalahari Craton and the Bushmanland Subprovince. This granitic gneiss is nonconformably overlain by the metasediments of the Korannaland Group that contains metamorphic muscovite with Ar-40/Ar-39 ages of similar to 1116 Ma. This age suggest that complete closure of the ocean between the Proto-Kalahari Craton and Bushmanland Subprovince probably occurred about 50 Ma after the intrusion of the similar to 1166 Ma granitic gneisses

The first 5 years of the family clinic for HIV at Tygerberg hospital: Family demographics, survival of children and early impact of antiretroviral therapy

Background: Family clinics address the problems of HIV-infected children and their families. The aims were to document demographics of the children and caregivers attending the Family Clinic for HIV at Tygerberg Academic Hospital (TAH) and to investigate factors affecting disease progression in children. Methods: A retrospective folder review of children and parents attending the Family Clinic at TAH between January 1997 and December 2001, a period noted for its lack of antiretroviral treatment. Results: Of 432 children seen for testing, 274 children, median age 16.9 months, were HIV-infected. During follow-up, 46 children died (median age 23 months) and 113 were lost to follow-up. The majority of children were malnourished. Those <2 years of age had lower weight for age Z-scores (WAZ) than older children (p<0.001). At presentation, 47 per cent were in clinical stage B and two-thirds had moderate or severe CD4+ T cell depletion. Seventeen children had received highly active antiretroviral therapy (HAART), 12 dual and 31 monotherapy. HAART was associated with improved survival compared to dual or monotherapy. Risk of death was reduced from eleven-fold for a WAZ <-4 to four-fold between -2 and -3. There was no association with immunological and clinical classification at entry and risk of mortality. Only 18 per cent of parents were evaluated in the clinic. Non-parental care was documented for 25 per cent of families. Conclusions: A low WAZ is associated with poor survival in children. Nutritional status should receive more attention in HIV disease classification in children. Parent utilization of the clinic was inadequate. Even in the absence of HAART, extended survival in children is possible. © The Author [2005]. Published by Oxford University Press. All rights reserved.Articl

Influência de métodos de debicagem e do tipo de bebedouro no desempenho e na qualidade dos ovos de codornas japonesas Beak trimming method and drinking system and a their effect on the performance and egg quality of japanese quails

Com o objetivo de avaliar o efeito da debicagem e do tipo de bebedouro sobre o desempenho produtivo de codornas japonesas, 672 fêmeas de codornas de um dia foram usadas em um delineamento inteiramente casualizado e distribuídas em um dos três tratamentos como não-debicagem; debicagem até 1/3 dos bicos; e cauterização, com oito repetições de 28 aves na fase de cria. As aves foram debicadas aos 21 dias de idade e, no 35 dia, foram avaliados o ganho de peso, o consumo de ração, a conversão alimentar e a taxa de mortalidade. Aos 39 dias, 576 codornas foram remanejadas para gaiolas de postura, distribuídas em esquema fatorial 3 × 2, composto de três tipos de debicagem e dois tipos de bebedouro (taça e nipple), de modo que cada combinação foi avaliada com quatro repetições de 24 aves. A fase de produção teve início quando as aves atingiram 50% de produção de ovos, aos 60 dias de idade. As codornas submetidas a debicagem por cauterização apresentaram menor ganho de peso e menor consumo de ração na fase de cria. O estresse pela dor com a debicagem por cauterização pode justificar não só o menor consumo e o menor ganho de peso, como também a maior mortalidade. Infere-se que este método, por ser mais demorado, tenha provocado mais dor e maior nível de estresse, piorando o desempenho das aves. A debicagem de 1/3 dos bicos cortados pode ter ocasionado estresse menos intenso às aves, não interferindo no desempenho. Não se observaram diferenças no desempenho das aves e na qualidade de ovos entre os tipos de bebedouro e métodos de debicagem utilizado na fase de produção. O método de debicagem por cauterização influencia o desempenho de codornas na fase de cria, mas, na fase de produção, assim como o tipo de bebedouro utilizado, não interfere no desempenho das aves nem na qualidade de ovos.<br>A total of 672 one day old- female quails was allotted to a completely randomized experimental design, with three treatments (non-trimmed birds; 1/3 of the beak trimmed and cauterized beak), 8 replicates of 28 birds to evaluate the effect of beak trimming and drinking system on productive performance. The birds were beak trimmed at 21 days of age, and at day 35 the weight gain, feed intake, feed conversion and mortality were evaluated. At day 39, 576 quails were transfered to laying cages, and assigned to a 3x2 factorial arrangement, to evaluate three beak trimming methods and two drinking systems (cup and nipple) by using four replicates of 24 birds each. The production phase started when the birds reached 50% egg production, at 60 days of age. The quails submitted to beak trimming by cauterization showed smaller weight and lower feed intake during the initial period. Stress pain due to the cauterized beak can justify not only lower feed intake and lower weight gain, but also increased mortality. It can be inferred that once this method takes more time it has caused more pain and higher levels of stress, worsening the performance of birds. The trimmed to 1/3 of the beaks cut can have caused stress to the birds less intense, without effect on performance. No differences on bird performance and egg quality were observed between drinking systems and beak trimming during the laying phase. In the initial phase, beak trimming system reduced performance, however, during the production phase, both drinking and beak trimming systems do not affect performance and egg quality of Japanese quails