3,932 research outputs found

    Archaeal Communities of Frozen Quaternary Sediments of Marine Origin on the Coast of Western Spitsbergen

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    The archaeal composition of permafrost samples taken during the drilling of frozen marine sediments in the area of the Barentsburg coal mine on the east coast of Grønfjord Bay of Western Spitsbergen has been studied. This study is based on an analysis of the V4 region of the 16S rRNA gene, carried out using next-generation sequencing. The general phyla of the Archaea domain are Euryarchaeota, Bathyarchaeota, Thaumarchaeota, and Asgardarchaea. As a result of a phylogenetic analysis of the dominant operational taxonomic units, representatives of methanogenic and methane- and ammonium-oxidizing archaea, as well as heterotrophic archaea, are found. The methanogenic archaea of Euryarchaeota phylum, Methanobacteria class, are found in permafrost with controversial genesis, while the methane-oxidizing archaea of Methanomicrobia class Methanosarcinales order are found in the marine permafrost at Cape Finneset: the ANME-2a, -2b group in layers of 8.6 and 11.7 m and the ANME-2d group (Candidatus Methanoperedens) in a layer of 6.5 m. Ammonium-oxidizing archaea of phylum Thaumarchaeota is present in all types of permafrost, while the order of Nitrososphaerales is found in permafrost with controversial genesis and the order Nitrosopumilales is in permafrost with marine and controversial genesis. Representatives of phylum Bathyarchaeota are found stratigraphically in the most ancient samples under study. Asgardarchaeota superfylum is excluded in the layers of permafrost with marine genesis and is represented by the phyla Lokiarchaeota, Thorarchaeota, and an unclassified group belonging to this superphylum. The presence of methane, ethylene, and ethane in the permafrost of the first sea terrace of Cape Finneset at a depth of 11.7 m, as well as the composition of the archaeal community, give us reason to assume that, before freezing, microbiological processes of anaerobic methane oxidation took place in it, probably received from Tertiary rocks. The results of both this and previous works present the Spitsbergen permafrost as a rich archive of genetic information of little-studied prokaryotic groups

    Bacterial Communities of Frozen Quaternary Sediments of Marine Origin on the Coast of Western Spitsbergen

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    The bacterial composition of permafrost samples taken during drilling of frozen marine sediments in the area of Barentsburg coal mine on the east coast of Grønfjord Bay of Western Spitsbergen has been studied. The study was based on the analysis of the V4 region of the 16S rRNA gene, carried out using next generation sequencing, as well as using classical microbiological methods (direct luminescence microscopy and aerobic cultivation).The total cell number in permafrost samples ranges from 6.73 ± 0.73 × 106 to 3.37 ± 0.19 107 cells per g. The number of cultivable aerobic bacteria in frozen samples on 1/5 TSA and R2A media ranges from 0 to 6.20 ± 0.45 × 104 CFU/g. Isolates of aerobic bacteria were identified by 16S rRNA gene analysis as representatives of the genera Arthrobacter, Pseudarthrobacter, Psychrobacter, and Rhodoferax. The dominant phyla of the domain Bacteria were Actinobacteria, Proteobacteria, Chloroflexi, Nitrospirae and Firmicutes. As a result of phylogenetic analysis of the dominant operational taxonomic units, representatives of methane oxidizing, sulfate reducing bacteria, as well as heterotrophic bacteria involved in the transformation of organic matter were found

    The effects of a sleep/recovery supplement: 'Night Time Recharge' on sleep parameters in young adults.

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    BACKGROUND: Concentrated cherry juice reportedly contains melatonin which, in turn, has been highlighted as an important regulator in initiating sleep. AIM: The present investigation aims to clarify whether Night Time Recharge (NTR), a marketed sleep aid containing cherry extract, improves key sleep parameters in young, active adults with mildly poor sleep. METHODS: A double-blind, randomized, placebo-controlled, cross-over study design was employed. Twenty participants (nine female) consumed either NTR or a placebo for seven days. Accelerometers were used to assess sleep quality and physical activity levels. Urinary levels of 6-sulphatoxymelatonin (6-SMT), a marker of melatonin synthesis, was assessed via enzyme-linked immunosorbent assay. RESULTS: 6-SMT levels increased following NTR treatment (28.95 ng/ml) compared with placebo (4.0 ng/ml) (p < 0.001). There was also a significant difference (p = 0.047) in dietary tryptophan consumption during the NTR treatment (1236 mg) versus placebo (1149 mg). No trace of melatonin was detected from our analysis of the supplement. NTR had no significant effect on any sleep parameters with the exception of sleep latency (p = 0.001). CONCLUSIONS: As chemical analysis of NTR by liquid-chromatography mass-spectrometry identified no detectable melatonin, the tryptophan content of the supplement is a likely reason for improvement in sleep latency. These results are in contrast to previous studies which have found a positive effect on sleep following cherry supplementation. Future work should focus on sleep latency and investigating whether cherry juice is effective in participants with problems in initiating sleep

    BRS "Symmetry", prehistory and history

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    Prehistory - Starting from 't Hooft's (1971) we have a short look at Taylor's and Slavnov's works (1971-72) and at the lectures given by Rouet and Stora in Lausanne-1973 which determine the transition from pre-history to history. History - We give a brief account of the main analyses and results of the BRS collaboration concerning the renormalized gauge theories, in particular the method of the regularization independent, algebraic renormalization, the algebraic proof of S-matrix unitarity and that of gauge choice independence of the renormalized physics. We conclude this report with a suggestion to the crucial question: what could remain of BRS invariance beyond perturbation theory.Comment: Talk given at: A Special day in honour of Raymond Stora, Annecy, July 8, 201

    The Impacts of Work-Life-Balance (WLB) Challenges on Social Sustainability: The Experience of Nigerian Female Medical Doctors

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    Purpose: The purpose of this paper is to examine the implications of work-life-balance (WLB) challenges for Nigerian female medical doctors. This study focusses on Nigeria, which its peculiar socio-cultural, institutional and professional realities constitute WLB as well as social sustainability (SS) challenge for female medical doctors. Design/methodology/approach: Relying on qualitative, interpretivist approach and informed by institutional theory, this study explores how Nigeria's institutional environment and workplace realities engender WLB challenges, which consequently impact SS for female doctors. In total, 43 semi-structured interviews and focus group session involving eight participants were utilised for empirical analysis. Findings: The study reveals that factors such as work pressure, cultural expectations, unsupportive relationships, challenging work environment, gender role challenges, lack of voice/participation, and high stress level moderate the ability of female medical doctors to manage WLB and SS. It also identifies that socio-cultural and institutional demands on women show that these challenges, while common to female physicians in other countries, are different and more intense in Nigeria because of their unique professional, socio-cultural and institutional frameworks. Research limitations/implications: The implications of the WLB and SS requires scholarship to deepen as well as extend knowledge on contextual disparities in understanding these concepts from developing countries perspective, which is understudied. Originality/value: This study offers fresh insights into the WLB and SS concepts from the non-western context, such as Nigeria, highlighting the previously understudied challenges of WLB and SS and their implications for female doctors. © 2018, Emerald Publishing Limited

    The Evolution of X-ray Clusters of Galaxies

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    Considerable progress has been made over the last decade in the study of the evolutionary trends of the population of galaxy clusters in the Universe. In this review we focus on observations in the X-ray band. X-ray surveys with the ROSAT satellite, supplemented by follow-up studies with ASCA and Beppo-SAX, have allowed an assessment of the evolution of the space density of clusters out to z~1, and the evolution of the physical properties of the intra-cluster medium out to z~0.5. With the advent of Chandra and Newton-XMM, and their unprecedented sensitivity and angular resolution, these studies have been extended beyond redshift unity and have revealed the complexity of the thermodynamical structure of clusters. The properties of the intra-cluster gas are significantly affected by non-gravitational processes including star formation and Active Galactic Nucleus (AGN) activity. Convincing evidence has emerged for modest evolution of both the bulk of the X-ray cluster population and their thermodynamical properties since redshift unity. Such an observational scenario is consistent with hierarchical models of structure formation in a flat low density universe with Omega_m=0.3 and sigma_8=0.7-0.8 for the normalization of the power spectrum. Basic methodologies for construction of X-ray-selected cluster samples are reviewed and implications of cluster evolution for cosmological models are discussed.Comment: 40 pages, 15 figures. Full resolution figures can be downloaded from http://www.eso.org/~prosati/ARAA

    Nonlinear W(infinity) Algebra as Asymptotic Symmetry of Three-Dimensional Higher Spin Anti-de Sitter Gravity

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    We investigate the asymptotic symmetry algebra of (2+1)-dimensional higher spin, anti-de Sitter gravity. We use the formulation of the theory as a Chern-Simons gauge theory based on the higher spin algebra hs(1,1). Expanding the gauge connection around asymptotically anti-de Sitter spacetime, we specify consistent boundary conditions on the higher spin gauge fields. We then study residual gauge transformation, the corresponding surface terms and their Poisson bracket algebra. We find that the asymptotic symmetry algebra is a nonlinearly deformed W(infinity) algebra with classical central charges. We discuss implications of our results to quantum gravity and to various situations in string theory.Comment: 25 pages, no figure; v2. minor corrections, references added, v3. JHEP published versio

    GeneWaltz--A new method for reducing the false positives of gene finding

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    <p>Abstract</p> <p>Background</p> <p>Identifying protein-coding regions in genomic sequences is an essential step in genome analysis. It is well known that the proportion of false positives among genes predicted by current methods is high, especially when the exons are short. These false positives are problematic because they waste time and resources of experimental studies.</p> <p>Methods</p> <p>We developed GeneWaltz, a new filtering method that reduces the risk of false positives in gene finding. GeneWaltz utilizes a codon-to-codon substitution matrix that was constructed by comparing protein-coding regions from orthologous gene pairs between mouse and human genomes. Using this matrix, a scoring scheme was developed; it assigned higher scores to coding regions and lower scores to non-coding regions. The regions with high scores were considered candidate coding regions. One-dimensional Karlin-Altschul statistics was used to test the significance of the coding regions identified by GeneWaltz.</p> <p>Results</p> <p>The proportion of false positives among genes predicted by GENSCAN and Twinscan were high, especially when the exons were short. GeneWaltz significantly reduced the ratio of false positives to all positives predicted by GENSCAN and Twinscan, especially when the exons were short.</p> <p>Conclusions</p> <p>GeneWaltz will be helpful in experimental genomic studies. GeneWaltz binaries and the matrix are available online at <url>http://en.sourceforge.jp/projects/genewaltz/</url>.</p
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