244 research outputs found

    Hydrogeological investigations in the Pampa of Argentina

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    The author has identified the following significant results. Satellite imagery in combination with ground investigations allows identification and delineation of differences in the conditions of the near surface ground water (depth to ground water, salinity). The degree of precision achieved is greater than that obtainable by conventional ground survey methods alone

    BrEPS: a flexible and automatic protocol to compute enzyme-specific sequence profiles for functional annotation

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    <p>Abstract</p> <p>Background</p> <p>Models for the simulation of metabolic networks require the accurate prediction of enzyme function. Based on a genomic sequence, enzymatic functions of gene products are today mainly predicted by sequence database searching and operon analysis. Other methods can support these techniques: We have developed an automatic method "BrEPS" that creates highly specific sequence patterns for the functional annotation of enzymes.</p> <p>Results</p> <p>The enzymes in the UniprotKB are identified and their sequences compared against each other with BLAST. The enzymes are then clustered into a number of trees, where each tree node is associated with a set of EC-numbers. The enzyme sequences in the tree nodes are aligned with ClustalW. The conserved columns of the resulting multiple alignments are used to construct sequence patterns. In the last step, we verify the quality of the patterns by computing their specificity. Patterns with low specificity are omitted and recomputed further down in the tree. The final high-quality patterns can be used for functional annotation. We ran our protocol on a recent Swiss-Prot release and show statistics, as well as a comparison to PRIAM, a probabilistic method that is also specialized on the functional annotation of enzymes. We determine the amount of true positive annotations for five common microorganisms with data from BRENDA and AMENDA serving as standard of truth. BrEPS is almost on par with PRIAM, a fact which we discuss in the context of five manually investigated cases.</p> <p>Conclusions</p> <p>Our protocol computes highly specific sequence patterns that can be used to support the functional annotation of enzymes. The main advantages of our method are that it is automatic and unsupervised, and quite fast once the patterns are evaluated. The results show that BrEPS can be a valuable addition to the reconstruction of metabolic networks.</p

    Increasing hepatitis B vaccination coverage and decreasing hepatitis B co-infection prevalence among people with HIV-1 in Germany, 1996–2019. Results from a cohort study primarily in men who have sex with men

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    Objectives Viral hepatitis co-infection among people living with HIV is known to accelerate the progression of liver disease and AIDS. An increased prevalence and incidence of hepatitis B virus (HBV) infection among people living with HIV demands continuous monitoring to adapt targeted prevention strategies to reach the global goals of eliminating viral hepatitis as a public health threat. Methods We determined the prevalence and incidence of HBV for the years 1996–2019 from yearly blood sample testing and questionnaire reports among people living with HIV belonging to a nationwide, multicentre observational, prospective cohort study. Results Among this study population of 3479 participants, the majority (87%) indicated that being men who have sex with men (MSM) was their likely HIV transmission route; 51% were recruited from Berlin. HBV prevalence for acute/chronic and resolved infections decreased from 4.1% and 45% in 1996–1999 to 1.3% and 16% in 2019, respectively. Simultaneously, participants with a serological status indicating HBV vaccination increased from 25% in 1996–1999 to 69% in 2019. Among vaccinated participants with relevant information (n = 1135), 38% received their first HBV vaccination after HIV infection. The HBV incidence rate in 565 eligible participants decreased from 6.9/100 person-years in 2004–2007 to 0.45/100 person-years in 2015. Conclusion Increasing vaccination coverage because of a general HBV vaccination recommendation and catch-up vaccination efforts among risk groups decreased HBV infection prevalence over time among this study population of people living with HIV, primarily MSM and from Berlin. Despite this success, the prevalence and incidence of HBV remains higher than in the general population in Germany. This emphasizes the need for continued HBV prevention by promoting HBV vaccination and HBV screening at regular intervals based on the individual risk behaviour.Peer Reviewe

    Defending the genome from the enemy within:mechanisms of retrotransposon suppression in the mouse germline

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    The viability of any species requires that the genome is kept stable as it is transmitted from generation to generation by the germ cells. One of the challenges to transgenerational genome stability is the potential mutagenic activity of transposable genetic elements, particularly retrotransposons. There are many different types of retrotransposon in mammalian genomes, and these target different points in germline development to amplify and integrate into new genomic locations. Germ cells, and their pluripotent developmental precursors, have evolved a variety of genome defence mechanisms that suppress retrotransposon activity and maintain genome stability across the generations. Here, we review recent advances in understanding how retrotransposon activity is suppressed in the mammalian germline, how genes involved in germline genome defence mechanisms are regulated, and the consequences of mutating these genome defence genes for the developing germline

    Supporting self-regulated learning

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    Self-regulated learning (SRL) competences are crucial for lifelong learning. Their cultivation requires the right balance between freedom and guidance during the learning processes. Current learning systems and approaches, such as personal learning environments, give overwhelming freedom, but also let weak learners alone. Other systems, such as learning management systems or adaptive systems, tend to institutionalise learners too much, which does not support the development of SRL competences. This chapter presents possibilities and approaches to support SRL by the use of technology. After discussing the theoretical background of SRL and related technologies, a formal framework is presented that describes the SRL process, related competences, and guidelines. Furthermore, a variety of methods is presented, how learners can be supported to learn in a self-regulated way
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