84 research outputs found

    Extragalactic Relativistic Jets and Nuclear Regions in Galaxies

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    Past years have brought an increasingly wider recognition of the ubiquity of relativistic outflows (jets) in galactic nuclei, which has turned jets into an effective tool for investigating the physics of nuclear regions in galaxies. A brief summary is given here of recent results from studies of jets and nuclear regions in several active galaxies with prominent outflows.Comment: 5 pages; contribution to ESO Astrophysical Symposia, "Relativistic Astrophysics and Cosmology", eds. B. Aschenbach, V. Burwitz, G. Hasinger, B. Leibundgut (Springer: Heidelberg 2006

    Active Galactic Nuclei at the Crossroads of Astrophysics

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    Over the last five decades, AGN studies have produced a number of spectacular examples of synergies and multifaceted approaches in astrophysics. The field of AGN research now spans the entire spectral range and covers more than twelve orders of magnitude in the spatial and temporal domains. The next generation of astrophysical facilities will open up new possibilities for AGN studies, especially in the areas of high-resolution and high-fidelity imaging and spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These studies will address in detail a number of critical issues in AGN research such as processes in the immediate vicinity of supermassive black holes, physical conditions of broad-line and narrow-line regions, formation and evolution of accretion disks and relativistic outflows, and the connection between nuclear activity and galaxy evolution.Comment: 16 pages, 5 figures; review contribution; "Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century", ESO Astrophysical Symposia Serie

    A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond

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    Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i)Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access toAntarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.Tinker Foundation, Antarctica New Zealand, The New Zealand Antarctic Research Institute, the Scientific Committee on Antarctic Research (SCAR), the Council of Managers of National Antarctic Programs (COMNAP), the Alfred Wegner Institut, Helmholtz Zentrum für Polar und Meeresforschung (Germany), and the British Antarctic Survey (UK).http://journals.cambridge.org/action/displayJournal?jid=ANShb201

    Activity profiling of papain-like cysteine proteases in plants

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    Transcriptomic and proteomic technologies are generating a wealth of data that are frequently used by scientists to predict the function of proteins based on their expression or presence. However, activity of many proteins, such as transcription factors, kinases, and proteases, depends on posttranslational modifications that frequently are not detected by these technologies. Therefore, to monitor activity of proteases rather than their abundance, we introduce protease activity profiling in plants. This technology is based on the use of biotinylated, irreversible protease inhibitors that react with active proteases in a mechanism-based manner. Using a biotinylated derivative of the Cys protease inhibitor E-64, we display simultaneous activities of many papain-like Cys proteases in extracts from various tissues and from different plant species. Labeling is pH dependent, stimulated with reducing agents, and inhibited specifically by Cys protease inhibitors but not by inhibitors of other protease classes. Using one-step affinity capture of bintinylated proteases followed by sequencing mass spectrometry, we identified proteases that include xylem-specific XCP2, desiccation-induced RD21, and cathepsin B- and aleurain-like proteases. Together, these results demonstrate that this technology can identify differentially activated proteases and/or characterize the activity of a particular protease within complex mixtures

    Perceptions of parental secure base support in African American adolescents and young adults: A preliminary study of predictive links to adult C-reactive protein

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    Item does not contain fulltextWithin the field of relationship science there is increasing interest in the connections between close relationships and physical health. In the present study, we examined whether adolescents' (~12 years old) and young adults' (~20 years old) perceptions of their parents as a secure base prospectively predict C-reactive protein (CRP), a commonly used marker of inflammatory activity, at age 32 in a well-characterized sample of African Americans. We utilized existing data collected as part of the Maryland Adolescent Development in Context Study (MADICS) to construct measures of perceptions of parental secure base support (SBS), general parental support, and peer support in early adolescence and early adulthood. In the present study, SBS was operationalized as the perceived ability to depend on parents in times of need. Fifty-nine African American MADICS participants who reported on perceived support in early adolescence and early adulthood participated in a follow-up home visit at age 32 during which serum CRP was measured via a blood draw. After controlling for inflammation-related confounds (e.g., tobacco use, body mass index), adolescents' perceptions of parental SBS, but not peer support or general parental support, predicted lower CRP values at age 32 (b = -.92, SE = .34, p < .05). None of the support variables in early adulthood predicted CRP at 32 years. This study adds to a growing literature on relationships and health-related outcomes and provides the first evidence for a link between parental SBS in adolescence and a marker of inflammatory activity in adulthood.18 p
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