189 research outputs found

    Reliability of AMS 14C dates of moss temper preserved in Neolithic pottery from the Scheldt river valley (Belgium)

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    Direct dates of pottery obtained from food crusts or other organic residues on the vessel surfaces can be affected by a reservoir effect and/or an old wood effect and therefore be unreliable. Hence, there is a need for alternative ways to directly date pottery. Moss is used as temper by several cultural groups of the late 6th to early 4th millennium cal BC in northwestern Europe. After the pottery is fired, charred moss remains are often preserved in the clay, so that relatively short-lived plant material with a direct chronological link to the pottery and human occupation is available for radiocarbon (C-14) dating. In this study, charred moss temper is extracted for accelerator mass spectrometry (AMS) C-14 dating from pottery of the Swifterbant Culture and Spiere group in the Scheldt river valley (Belgium). The moss dates are then compared to reference dates of organic macro-remains from the same sites and food crust dates with or without a reservoir effect of the same pottery. Eleven out of 13 moss dates are in line with the expected pottery age. The paired dates of moss temper and food crusts from the same potsherds confirm a freshwater reservoir effect (FRE) for the latter. We conclude that moss temper has great potential as a sample material for direct pottery dating. However, more research on the extraction and pretreatment of moss temper as well as on the reliability of moss dates is necessary in the future

    The Macquenoise sandstone : a suitable Lochkovian raw material for ancient millstones : quarries, properties, manufacture and distribution (Belgium-France)

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    International audienceSince a few years a French-Belgian team of archeologists and geologists work on the characterization of ancient quern stones and millstones (mainly from the Antique period) linked with the identification of their stratigraphical and geographical provenances.This fruitful collaboration aims at reconstructing the ancient commercial roads and economic organization of territories during that period.In addition to the better-known volcanic rocks from the Eifel area, our study revealed the frequent occurrence of particular Devonian conglomerates and sandstones from the Ardenne area, as raw materials for the manufacturing of querns and millstones. The latter sandstones as well as the related antique millstone quarries, form an important and until now undervalued geological and cultural heritage in Belgium.Near the Ardenne border between France and Belgium, the earliest Devonian (Lochkovian) sediments deposited on the Caledonian substrate are conglomerates, which are interpreted as continental alluvial fans. The first marine sediments are littoral sandstones/quartzites or shales/slates. A sandstone formation, formally defined as the “Arkose d’Haybes” is closely linked to the former Lochkovian conglomerates (called also the “Poudingue de Fépin”). The outcrops of this particular formation around the reference localities of Haybes, Fépin and Hargnies (Ardennes, France), show a partly recrystallized, well-sorted grey to greenish sandstone (turbidite facies) with wine-red coloured joints. Another important area displaying old quarries in the same formation is located between Hirson (Aisne, France) and Macquenoise (Hainaut, Belgium): here, a more homogenous grey coarse sandstone facies occurs, with a better consistency and small amounts of dark green tourmaline crystals.These detrital formations were locally quarried, not only for building stones but also for the production of querns and millstones. The huge Proto-historical and Roman millstone quarries in Lochkovian conglomerates and sandstones from Macquenoise are known since the 19th century. Even if the lack of recent archeological excavations do not allow yet to precise the exact age of their quarrying, the dating of the various products derived from these quarries allow to consider the duration of the active extraction and how far the millstones from Macquenoise area were transported into the northern Gallo-Roman provinces

    The Effect of Complete Integration of HIV and TB Services on Time to Initiation of Antiretroviral Therapy: A Before-After Study.

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    Studies have shown that early ART initiation in TB/HIV co-infected patients lowers mortality. One way to implement earlier ART commencement could be through integration of TB and HIV services, a more efficient model of care than separate, vertical programs. We present a model of full TB/HIV integration and estimate its effect on time to initiation of ART

    Effectiveness of the first district-wide programme for the prevention of mother-to-child transmission of HIV in South Africa

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    Objective: The aim of this study was to estimate the field efficacy of the first routine programme for the prevention of mother-to-child transmission (PMTCT) of human immunodeficiency virus (HIV) initiated in South Africa, in the subdistrict of Khayelitsha. Methods: A consecutive sample of 658 mother–infant pairs, identified from the PMTCT register from 1 March to 30 November 2003, were identified for enrolment in this study. Details of the regimen received were established and HIV status of the infants at between 6 and 10 weeks of age was determined by qualitative DNA polymerase chain reaction. Zidovudine (AZT) was provided antenatally from week 34 of gestation and during labour. Infant formula milk was offered to mothers who chose not to breastfeed. The protocol was amended in July 2003 such that women who had received 25 years was the only significant independent risk factor for transmission (odds ratio, 2.12; 95% CI, 1.14–4.07). Conclusion: The results of this study demonstrate the feasibility and effectiveness of a large-scale PMTCT programme in an urban public-sector setting

    Preferred antiretroviral drugs for the next decade of scale up

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    Global commitments aim to provide antiretroviral therapy (ART) to 15 million people living with HIV by 2015, and recent studies have demonstrated the potential for widespread ART to prevent HIV transmission. Increasingly, countries are adapting their national guidelines to start ART earlier, for both clinical and preventive benefits. To maximize the benefits of ART in resource-limited settings, six key principles need to guide ART choice: simplicity, tolerability and safety, durability, universal applicability, affordability and heat stability. Currently available drugs, combined with those in late-stage clinical development, hold great promise to simplify treatment in the short term. Over the longer-term, newer technologies, such as long-acting formulations and nanotechnology, could radically alter the treatment paradigm. This commentary reviews recommendations made in an expert consultation on treatment scale up in resource-limited settings

    Cost and cost-effectiveness of switching from d4T or AZT to a TDF-based first-line regimen in a resource-limited setting in rural Lesotho

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    Article approval pendingLatest World Health Organization guidelines recommend shifting away from Stavudine (d4T)-based regimens due to severe side effects. However, widespread replacement of d4T by Tenofovir (TDF) or Zidovudine (AZT) is hampered by cost concerns
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