Yersinia pestis DNA from Skeletal Remains from the 6(th) Century AD Reveals Insights into Justinianic Plague.

Yersinia pestis, the etiologic agent of the disease plague, has been implicated in three historical pandemics. These include the third pandemic of the 19(th) and 20(th) centuries, during which plague was spread around the world, and the second pandemic of the 14(th)-17(th) centuries, which included the infamous epidemic known as the Black Death. Previous studies have confirmed that Y. pestis caused these two more recent pandemics. However, a highly spirited debate still continues as to whether Y. pestis caused the so-called Justinianic Plague of the 6(th)-8(th) centuries AD. By analyzing ancient DNA in two independent ancient DNA laboratories, we confirmed unambiguously the presence of Y. pestis DNA in human skeletal remains from an Early Medieval cemetery. In addition, we narrowed the phylogenetic position of the responsible strain down to major branch 0 on the Y. pestis phylogeny, specifically between nodes N03 and N05. Our findings confirm that Y. pestis was responsible for the Justinianic Plague, which should end the controversy regarding the etiology of this pandemic. The first genotype of a Y. pestis strain that caused the Late Antique plague provides important information about the history of the plague bacillus and suggests that the first pandemic also originated in Asia, similar to the other two plague pandemics

Особенности упрочнения и разрушения аустенитной стали в условиях разных схем воздействия мегавольтного электронного луча

В данной исследовательской работе были исследованы образцы 304L после ударно-волнового нагружения сильноточным наносекундным релятивистским электронным пучком.. Целью данной работы является исследование влияния многократного динамического нагружения образцов стали 304L при изменении схемы воздействия на эволюцию структуры материала по объему мишени. С бурным развитием авиакосмической техники и современного высокоскоростного воздействия на материалы к ним предъявляются жесткие требования по комплексу физико-механических свойств. Однако в реальных условиях эксплуатации такому воздействию материал может подвергаться неоднократно, меняя схему нагружения. Это в частности касается воздействия УВ как с фронтальной, так и с тыльной части мишени.In this research work, 304L samples were studied after shock-wave loading by a high-current nanosecond relativistic electron beam .. The aim of this work is to study the effect of multiple dynamic loading of 304L steel samples when changing the pattern of influence on the evolution of the material structure over the target volume. With the rapid development of aerospace engineering and modern high-speed impact on materials, stringent requirements are imposed on them for a set of physical and mechanical properties. However, under real operating conditions, the material can be exposed to this effect repeatedly, changing the loading scheme. This is particularly true for the impact of hydrocarbons from both the front and the back of the target

Yersinia pestis Lineages in Mongolia

BACKGROUND: Whole genome sequencing allowed the development of a number of high resolution sequence based typing tools for Yersinia (Y.) pestis. The application of these methods on isolates from most known foci worldwide and in particular from China and the Former Soviet Union has dramatically improved our understanding of the population structure of this species. In the current view, Y. pestis including the non or moderate human pathogen Y. pestis subspecies microtus emerged from Yersinia pseudotuberculosis about 2,600 to 28,600 years ago in central Asia. The majority of central Asia natural foci have been investigated. However these investigations included only few strains from Mongolia. METHODOLOGY/PRINCIPAL FINDINGS: Clustered Regularly Interspaced Short Prokaryotic Repeats (CRISPR) analysis and Multiple-locus variable number of tandem repeats (VNTR) analysis (MLVA) with 25 loci was performed on 100 Y. pestis strains, isolated from 37 sampling areas in Mongolia. The resulting data were compared with previously published data from more than 500 plague strains, 130 of which had also been previously genotyped by single nucleotide polymorphism (SNP) analysis. The comparison revealed six main clusters including the three microtus biovars Ulegeica, Altaica, and Xilingolensis. The largest cluster comprises 78 isolates, with unique and new genotypes seen so far in Mongolia only. Typing of selected isolates by key SNPs was used to robustly assign the corresponding clusters to previously defined SNP branches. CONCLUSIONS/SIGNIFICANCE: We show that Mongolia hosts the most recent microtus clade (Ulegeica). Interestingly no representatives of the ancestral Y. pestis subspecies pestis nodes previously identified in North-western China were identified in this study. This observation suggests that the subsequent evolution steps within Y. pestis pestis did not occur in Mongolia. Rather, Mongolia was most likely re-colonized by more recent clades coming back from China contemporary of the black death pandemic, or more recently in the past 600 years

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Isolation of the Amoeba Thecamoeba quadrilineata Harbouring Intranuclear Spore Forming Endoparasites Considered as Fungus-like Organisms

Among a population of Thecamoeba quadrilineata (Thecamoebidae) isolated from moss samples some trophozoites harboured intracellular aggregates of round-oval parasites which turned out to be spores with a real nucleus. These organisms were supposed to be fungal endoparasites beginning their development within the nucleus of the host invaded by young parasitic stages after the host amoeba had engulfed free spores from the environment. The complete developmental cycle was studied by electron microscopy, showing the intranuclear growth of freshly invaded young stages into large spore forming parasites differentiating into a great number of spores – all within the border of the host’s nuclear membrane. These spores were not released into the environment until the death and decay of the host amoeba, where they could be ingested as infective stages by hitherto not infected thecamoebae. Host range studies with various free-living amoebae (FLA) showed that T. striata and T. terricola were as permissive to infection as the original host T. quadrilineata. Sappinia was only susceptible to a certain extent and therefore not considered as possible natural host. Remarkably, this observation shows that both nuclei of the bi-nucleate amoeba became simultaneously infected. The present morphological description corresponds to early observations with fungal intranuclear parasites called Nucleophaga Dangeard, 1887. However, genetic and phylogenetic studies have to corroborate the supposed fungal nature

Combined Color And Texture Segmentation by Parametric Distributional Clustering

Unsupervised image segmentation can be formulated as a clustering problem in which pixels or small image patches are grouped together based on local feature information. In this contribution, parametric distributional clustering (PDC) is presented as a novel approach to image segmentation based on color and texture clues. The objective function of the PDC model is derived from the recently proposed Information Bottleneck framework (Tishby et al. [8]), but it can equivalently be formulated in terms of a maximum likelihood solution. Its optimization is performed by deterministic annealing. Segmentation results are shown for natural wildlife imagery