242 research outputs found

    Radiocarbon dates for the late Pleistocene and Early Holocene occupations of Cova Rosa (Ribadesella, Asturias, Spain)

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    Four excavations have been performed at the archaeological site of Cova Rosa (Asturias, Cantabrian Spain): three of them in the second half of last century and the other in this decade. Although little of the archaeological material found in those excavations has been published, here we attempt the stratigraphic correlation of sections revealed by the different excavations and we present 22 new radiocarbon dates for bones and marine shells, built in a Bayesian statistical model. This has enabled the documentation of occupations that mainly took place during the Last Glacial period, in the Solutrean (middle and upper phases) and Magdalenian (archaic, lower, and upper phases), and also in the early Holocene (Mesolithic). These occupations are compared with the record at other sites in Cantabrian Spain in general and in Asturias, in particular.Introduction Cova Rosa Cave - Geographical and Geological Setting - History of Research - Stratigraphy Radiocarbon dates at Cova Rosa - Method - Validity Analysis - Results and Critical Assessment - Solutrean - Magdalenian - Mesolithic Discussion: 14C chronology of Cova Rosa Conclusion

    Squaring the Circle. Social and Environmental Implications of Pre-Pottery Neolithic Building Technology at Tell Qarassa (South Syria)

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    We present the results of the microstratigraphic, phytolith and wood charcoal study of the remains of a 10.5 ka roof. The roof is part of a building excavated at Tell Qarassa (South Syria), assigned to the Pre-Pottery Neolithic B period (PPNB). The Pre-Pottery Neolithic (PPN) period in the Levant coincides with the emergence of farming. This fundamental change in subsistence strategy implied the shift from mobile to settled aggregated life, and from tents and huts to hard buildings. As settled life spread across the Levant, a generalised transition from round to square buildings occurred, that is a trademark of the PPNB period. The study of these buildings is fundamental for the understanding of the ever-stronger reciprocal socio-ecological relationship humans developed with the local environment since the introduction of sedentism and domestication. Descriptions of buildings in PPN archaeological contexts are usually restricted to the macroscopic observation of wooden elements (posts and beams) and mineral components (daub, plaster and stone elements). Reconstructions of microscopic and organic components are frequently based on ethnographic analogy. The direct study of macroscopic and microscopic, organic and mineral, building components performed at Tell Qarassa provides new insights on building conception, maintenance, use and destruction. These elements reflect new emerging paradigms in the relationship between Neolithic societies and the environment. A square building was possibly covered here with a radial roof, providing a glance into a topologic shift in the conception and understanding of volumes, from round-based to square-based geometries. Macroscopic and microscopic roof components indicate buildings were conceived for year-round residence rather than seasonal mobility. This implied performing maintenance and restoration of partially damaged buildings, as well as their adaptation to seasonal variability.MICINN (HAR2011-21545-C02-01) The last hunter-gatherers and the first producing societies in Central and Southern Syria, the Ministry of Culture Spanish Institute of Cultural Heritage (Excavations Abroad), the French Ministry of Foreign and European Affairs, JAEDoc (contracts for A. Balbo), SimulPast Consolider and European Social Found, the Basque Government (Pre-doctoral grant Number: BFI.09.249 for A. Arranz), Basque Government-Research Group UPV/EHU IT-288-07 (L. Zapata), UFI11/09 Cuaternario of the UPV/EHU and Project HAR2011-23716 (I+D+i), Programa de Movilidad del Personal Investigador del Gobierno Vasco 2012, AGRIWESTMED (European Research Council funded) (contract for C. Lancelotti)

    Pla d’acció enfront de la infecció pel VIH i les altres ITS 2021-2030

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    Pla d'acció; VIH; Infeccions de transmissió sexualPlan de acción; VIH; Infecciones de transmisión sexualAction plan; HIV; Sexually transmitted infectionsArticle on s'explica la finalitat del Pla d’acció enfront de la infecció pel VIH i les altres ITS 2021-2030. Aquesta és facilitar l’adopció i la implementació de les mesures necessàries per reduir la incidència de la infecció pel VIH i per altres ITS, facilitar l’accés precoç al tractament i millorar la qualitat de vida de les persones infectades, així com reduir l’estigmatització associada a aquestes infeccions mitjançant l’acció comunitària per a la inclusió social

    Pla d’acció enfront del VIH i altres ITS 2021-2030

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    Pla d'acció; Prevenció; Malalties de transmissió sexual; CatalunyaPlan de acción; Prevención; Enfermedades de transmisión sexual; CataluñaAction plan; Prevention; Sexually transmitted diseases; CataloniaEl Pla d’acció enfront del VIH i altres ITS 2021-2030, aprovat per la Comissió Interdepartamental de la Sida a Catalunya (CISC), és el full de ruta de les actuacions que cal dur a terme en els propers anys en resposta al VIH/sida i les altres ITS. La finalitat d’aquest Pla d’acció és facilitar l’adopció i la implementació de les mesures necessàries per reduir la incidència de la infecció pel VIH i altres ITS, facilitar l’accés precoç al tractament i millorar la qualitat de vida de les persones infectades, així com reduir l’estigmatització associada a aquestes infeccions, mitjançant l’acció comunitària per a la inclusió social

    Empirical leucine-to-carbon conversion factors for estimating heterothrophic bacterial production in surface waters of the world oceans

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    Comunicación oralBacterial biomass production is a key parameter for evaluating the role of bacterioplankton in ocean carbon cycling. However, bacterial production cannot be directly measured and is typically estimated from the incorporation rates of radiolabelled leucine. The conversion of leucine uptake rates into bacterial carbon production rates requires the use of conversion factors (CFs) which must be empirically determined. Despite the empirical leucine-to-carbon CFs vary widely across environments very little is known about its potential controlling factors. We conducted a set of 10 surface seawater cultures experiments where the growth of the natural bacterial assemblage was promoted by filtration (removal of grazers) or by both filtration and dilution. Sampling stations were located between 30 ºN and 30 ºS, including the Atlantic, Pacific and Indian oceans. CFs varied from 0.13 to 1.47 Kg C mol Leu-1, being higher in the filtrated than in the filtrated and diluted treatment. The abundance of picocyanobacteria explained 60% of the observed variability. Our results further suggest that the composition of bacterioplankton, as assessed by ARISA fingerprinting, may partially explain the observed variation in CFs

    Sample dilution and bacterial community composition influence empirical leucine-to-carbon conversion factors in surface waters of the world's oceans

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    Research articleThe transformation of leucine incorporation into prokaryotic carbon production rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across environments, and little is known about their potential controlling factors. We conducted 10 surface seawater manipulation experiments across the world’s oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e. removal of grazers; F treatment) or filtration combined with dilution (i.e. relieving also resource competition; FD treatment). The impact of sunlight exposure was also evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The eCFs varied from 0.09 to 1.47 kg C mol Leu-1 and were significantly lower in the filtered and diluted (FD) than in the filtered (F) treatments. Also, changes in bacterial community composition during the incubations, as assessed by Automated Ribosomal Intergenic Spacer Analysis (ARISA), were stronger in the FD than in the F treatments, as compared to unmanipulated controls. Thus, we discourage the common procedure of diluting samples (in addition to filtration) for eCFs determination. The eCFs in the filtered treatment were negatively correlated with the initial chlorophyll a concentration, picocyanobacterial abundance (mostly Prochlorococcus) and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two variables explained 80% of the eCFs variability in the F treatment, supporting the view that both Prochlorococcus and HNA prokaryotes incorporate leucine in substantial amounts although resulting into relatively low carbon production rates in the oligotrophic ocean.En prensa3,829

    CD4 cell count and the risk of AIDS or death in HIV-Infected adults on combination antiretroviral therapy with a suppressed viral load: a longitudinal cohort study from COHERE.

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    BACKGROUND: Most adults infected with HIV achieve viral suppression within a year of starting combination antiretroviral therapy (cART). It is important to understand the risk of AIDS events or death for patients with a suppressed viral load. METHODS AND FINDINGS: Using data from the Collaboration of Observational HIV Epidemiological Research Europe (2010 merger), we assessed the risk of a new AIDS-defining event or death in successfully treated patients. We accumulated episodes of viral suppression for each patient while on cART, each episode beginning with the second of two consecutive plasma viral load measurements 500 copies/µl, the first of two consecutive measurements between 50-500 copies/µl, cART interruption or administrative censoring. We used stratified multivariate Cox models to estimate the association between time updated CD4 cell count and a new AIDS event or death or death alone. 75,336 patients contributed 104,265 suppression episodes and were suppressed while on cART for a median 2.7 years. The mortality rate was 4.8 per 1,000 years of viral suppression. A higher CD4 cell count was always associated with a reduced risk of a new AIDS event or death; with a hazard ratio per 100 cells/µl (95% CI) of: 0.35 (0.30-0.40) for counts <200 cells/µl, 0.81 (0.71-0.92) for counts 200 to <350 cells/µl, 0.74 (0.66-0.83) for counts 350 to <500 cells/µl, and 0.96 (0.92-0.99) for counts ≥500 cells/µl. A higher CD4 cell count became even more beneficial over time for patients with CD4 cell counts <200 cells/µl. CONCLUSIONS: Despite the low mortality rate, the risk of a new AIDS event or death follows a CD4 cell count gradient in patients with viral suppression. A higher CD4 cell count was associated with the greatest benefit for patients with a CD4 cell count <200 cells/µl but still some slight benefit for those with a CD4 cell count ≥500 cells/µl
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