44 research outputs found

    Hepatitis B virus and hepatitis D virus infection in women with or at risk for HIV infection in the United States

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    Hepatitis D virus (HDV) requires co-infection with hepatitis B virus (HBV). Human immunodeficiency virus (HIV) shares transmission routes with these viruses. Among 4,932 US women infected with or at-risk for HIV during 1994–2015, HBV surface antigen (HBsAg) positivity was more common in women with HIV (2.8% vs. 1.2%; p = 0.001); HDV was more common among participants enrolled during 2013–2015 (p = 0.0004) and those with resolved rather than active hepatitis C (1.9% vs. 0.5%; p = 0.02). Among HBsAg-positive women (n = 117), HDV antibody prevalence was 22% and did not vary by HIV status; HDV infection was associated with the presence of advanced fibrosis/cirrhosis at enrollment (adjusted odds ratio, 5.70; 95% confidence interval, 1.46–22.29). Our results demonstrate the importance of HDV testing in HBV-infected US women

    Comparative genomics of small RNA regulatory pathway components in vector mosquitoes

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    <p>Abstract</p> <p>Background</p> <p>Small RNA regulatory pathways (SRRPs) control key aspects of development and anti-viral defense in metazoans. Members of the Argonaute family of catalytic enzymes degrade target RNAs in each of these pathways. SRRPs include the microRNA, small interfering RNA (siRNA) and PIWI-type gene silencing pathways. Mosquitoes generate viral siRNAs when infected with RNA arboviruses. However, in some mosquitoes, arboviruses survive antiviral RNA interference (RNAi) and are transmitted via mosquito bite to a subsequent host. Increased knowledge of these pathways and functional components should increase understanding of the limitations of anti-viral defense in vector mosquitoes. To do this, we compared the genomic structure of SRRP components across three mosquito species and three major small RNA pathways.</p> <p>Results</p> <p>The <it>Ae. aegypti, An. gambiae </it>and <it>Cx. pipiens </it>genomes encode putative orthologs for all major components of the miRNA, siRNA, and piRNA pathways. <it>Ae. aegypti </it>and <it>Cx. pipiens </it>have undergone expansion of Argonaute and PIWI subfamily genes. Phylogenetic analyses were performed for these protein families. In addition, sequence pattern recognition algorithms MEME, MDScan and Weeder were used to identify upstream regulatory motifs for all SRRP components. Statistical analyses confirmed enrichment of species-specific and pathway-specific cis-elements over the rest of the genome.</p> <p>Conclusion</p> <p>Analysis of Argonaute and PIWI subfamily genes suggests that the small regulatory RNA pathways of the major arbovirus vectors, <it>Ae. aegypti and Cx. pipiens</it>, are evolving faster than those of the malaria vector <it>An. gambiae </it>and <it>D. melanogaster</it>. Further, protein and genomic features suggest functional differences between subclasses of PIWI proteins and provide a basis for future analyses. Common UCR elements among SRRP components indicate that 1) key components from the miRNA, siRNA, and piRNA pathways contain NF-kappaB-related and Broad complex transcription factor binding sites, 2) purifying selection has occurred to maintain common pathway-specific elements across mosquito species and 3) species-specific differences in upstream elements suggest that there may be differences in regulatory control among mosquito species. Implications for arbovirus vector competence in mosquitoes are discussed.</p

    Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies

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    The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes

    Establishing a high‐resolution stratigraphy in the Holocene marine sequence of the ancient Theodosian harbor of Istanbul with the help of dendrochronology

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    Salvage excavations in the Theodosian harbor (Yenikapi-Istanbul) have uncovered diverse archaeological objects including 36 shipwrecks and various Byzantine period wooden docks. The sequence of these docks provided a unique opportunity to obtain a high-resolution stratigraphy. The new approach is based on stratigraphic interpretation of deformation patterns created by the posts in soft sediments, combined with dendrochronological dating of the posts. Dendrochronology offers the potential to date the posts to within one calendar year of felling, a level of precision and accuracy rare in sedimentological analysis. The posts, most of them Quercus, were rammed during six different time periods. The first period is associated with posts cut in 528 AD. The second and third periods are dated by posts cut in 583 and 594 AD, respectively. The fourth-period dates within 8-10 years of 639 AD. The fifth period could be dated only roughly to between 690 and 770 AD. The last period produced a possible placement of after 778 AD. This new approach helps to establish a high-resolution stratigraphy. Furthermore, it provides information about sedimentation history and specific anthropogenic events

    Challenges of triangular relations: The US, the EU, and Turkish accession

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    The US government became deeply involved in European Union (EU)-Turkey relations from the mid-1990s and has provided extensive diplomatic support for full Turkish membership in the EU since then. Washington's strategic considerations have been paramount in the US government's approach to Turkey's full integration into the EU. The US policy on this issue has played a constructive role in Turkish-US relations. However, it has also created strains in transatlantic ties, since the pressure the US has put on the EU has angered many European officials, who resent what they view as interference in the EU's internal affairs. The US has become more sensitive to the complaints voiced by European leaders and EU officials, and it has adopted a more subtle approach to the issue of Turkish membership. While Washington continues to support Turkey's European integration, it has also recognised that the accession process is likely to be lengthy
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