432 research outputs found
Maternal antibody response at delivery and perinatal transmission of human immunodeficiency virus type 1 in African women
Зональные фораминиферовые схемы нижнего карбона западных регионов Украины
Запропоновано зональні форамініферові схеми нижнього карбону Придобруджинського прогину та Львівсько-Волинського басейну. У Придобруджинському прогині нараховується вісім зон і дві підзони, з них одна зона і дві підзони виділені вперше. У п'яти зон змінено види-індекси, У Львівсько-Волинському басейні є п’ять зон і дві підзони, з них одна зона нова. Дві колишні зони об'єднано в одну — з двома підзонами. Змінено види-індекси трьох зон. В обох регіонах уточнено обсяг зон та їх межі. Границі зон і підзон проведено за першою появою видів-індексів. Проведено зіставлення цих зональних схем із форамініферовими зонами Доно-Дніпровського регіону і Східно-Європейської платформи.Foraminiferal zonal schemes of the Lower Carboniferous of the Dobrudja Foredeep and Lvov-Volynian basin are proposed in the paper. The first scheme includes eight zones and two subzones; among them one zone and two subzones are specified for the first time. In five zones species-index is changed. The second scheme includes five zones and two subzones; one zone is specified for the first time. Two preceding zones are united into one with two subzones. In three zones species-index is changed. The boundaries of zones and subzones are determined according to the first occurrence of species-index. Correlation of these zones with foraminiferal zones of Dono-Dnieper region and East-European platform is performed
Transmission de la mère à l'enfant du virus HIV 1 : étude prospective à Brazzaville (R.P. Congo)
NanTroSEIZE Stage 1 expeditions: introduction and synthesis of key results
Integrated Ocean Drilling Program Expeditions 314, 315, and 316 were carried out as a unified program of drilling collectively known as Stage 1 of the Nankai Trough Seismogenic Zone Experiment, a multistage complex drilling project. A transect of eight sites was selected for riserless drilling to target the frontal thrust region, midslope megasplay fault region, and Kumano forearc basin region. Two of these sites are preparatory pilot holes for planned deep riser drilling operations, whereas the others targeted fault zone material in the shallow, presumed aseismic zone. Expedition 314 was dedicated to in situ measurement of physical properties and borehole imaging through logging while drilling in holes dedicated to that purpose. Expedition 315 was devoted to core sampling and downhole temperature measurements at one site in the megasplay region and one site in the forearc basin. Expedition 316 targeted the frontal and out-of-sequence megasplay fault region in the mid-slope environment. Results on accretionary complex structure, lithology and age, physical properties, and state of stress, which are documented in full in the site chapters of this volume, are here synthesized across the expeditions
Slab segmentation controls the interplate slip motion in the SW Hellenic subduction: New insight from the 2008Mw 6.8 Methoni interplate earthquake
We present an integrated approach of the seismic structure and activity along the offshore SW Hellenic subduction from combined observations of marine and land seismic stations. Our imaging of the slab top topography from teleseismic receiver function analysis at ocean bottom seismometers supports a trenchward continuation of the along-dip slab faults beneath the Peloponnesus. We further show that their morphostructural control accounts for the backstepping of the thrust contact of the Mediterranean Ridge accretionary wedge over the upper plate. Local seismic activity offshore SW Peloponnesus constrained by ocean bottom seismometer observations reveals a correlation with specific features of the forearc: the Matapan Troughs. We study the Mw6.8 14.02.2008 interplate earthquake offshore SW Peloponnesus and show that its nucleation, rupture zone, and aftershocks sequence are confined to one slab panel between two adjacent along-dip faults and are thus controlled by not only the offshore slab top segmentation but also the upper plate sea-bottom morphology
The impact of pre-exposure prophylaxis (PrEP) on HIV epidemics in Africa and India: A simulation study
Background: Pre-exposure prophylaxis (PrEP) is a promising new HIV prevention method, especially for women. An urgent demand for implementation of PrEP is expected at the moment efficacy has been demonstrated in clinical trials. We explored the long-term impact of PrEP on HIV transmission in different HIV epidemics. Methodology/Principal Findings: We used a mathematical model that distinguishes the general population, sex workers and their clients. PrEP scenarios varying in effectiveness, coverage and target group were modeled in the epidemiological settings of Botswana, Nyanza Province in Kenya, and Southern India. We also studied the effect of condom addition or condom substitution during PrEP use. Main outcome was number of HIV infections averted over ten years of PrEP use. PrEP strategies with high effectiveness and high coverage can have a substantial impact in African settings. In Southern India, by contrast, the number of averted HIV infections in different PrEP scenarios would be much lower. The impact of PrEP may be strongly diminished or even reversed by behavioral disinhibition, especially in scenarios with low coverage and low effectiveness. However, additional condom use during low coverage and low effective PrEP doubled the amount of averted HIV infections. Conclusions/Significance: The public health impact of PrEP can be substantial. However, this impact may be diminished, or even reversed, by changes in risk behavior. Implementation of PrEP strategies should therefore come on top of current condom campaigns, not as a substitution
Nucleoside Reverse Transcriptase Inhibitor Resistance Mutations Associated with First-Line Stavudine-Containing Antiretroviral Therapy: Programmatic Implications for Countries Phasing Out Stavudine
Background The World Health Organization Antiretroviral Treatment Guidelines recommend phasing-out stavudine because of its risk of long-term toxicity. There are two mutational pathways of stavudine resistance with different implications for zidovudine and tenofovir cross-resistance, the primary candidates for replacing stavudine. However, because resistance testing is rarely available in resource-limited settings, it is critical to identify the cross-resistance patterns associated with first-line stavudine failure. Methods We analyzed HIV-1 resistance mutations following first-line stavudine failure from 35 publications comprising 1,825 individuals. We also assessed the influence of concomitant nevirapine vs. efavirenz, therapy duration, and HIV-1 subtype on the proportions of mutations associated with zidovudine vs. tenofovir cross-resistance. Results Mutations with preferential zidovudine activity, K65R or K70E, occurred in 5.3% of individuals. Mutations with preferential tenofovir activity, ≥two thymidine analog mutations (TAMs) or Q151M, occurred in 22% of individuals. Nevirapine increased the risk of TAMs, K65R, and Q151M. Longer therapy increased the risk of TAMs and Q151M but not K65R. Subtype C and CRF01_AE increased the risk of K65R, but only CRF01_AE increased the risk of K65R without Q151M. Conclusions Regardless of concomitant nevirapine vs. efavirenz, therapy duration, or subtype, tenofovir was more likely than zidovudine to retain antiviral activity following first-line d4T therap
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