2,332 research outputs found

    The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment

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    Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and polarization \epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum of the outgoing photon in the photon-proton center of mass frame. The experiment has been performed with the high resolution spectrometers at the Mainz Microtron MAMI. From the photon angular distributions, two structure functions which are a linear combination of the generalized polarizabilities have been determined for the first time.Comment: 4 pages, 3 figure

    A Goal-Oriented Autonomous Controller for Space Exploration

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    The Goal-Oriented Autonomous Controller (GOAC) is the envisaged result of a multi-institutional effort within the on-going Autonomous Controller R&D activity funded by ESA ESTEC. The objective of this effort is to design, build and test a viable on-board controller to demonstrate key concepts in fully autonomous operations for ESA missions. This three-layer architecture is an integrative effort to bring together four mature technologies; for a functional layer, a verification and validation system, a planning engine and a controller framework for planning and execution which uses the sense-plan-act paradigm for goal oriented autonomy. GOAC as a result will generate plans in situ, deterministically dispatch activities for execution, and recover from off-nominal conditions

    Sumoylation Contributes to Timekeeping and Temperature Compensation of the Plant Circadian Clock

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    The transcriptional circadian clock network is tuned into a 24-h oscillator by numerous posttranslational modifications on the proteins encoded by clock genes, differentially influencing their subcellular localization or activity. Clock proteins in any circadian organism are subject to posttranslational regulation, and many of the key enzymes, notably kinases and phosphatases, are functionally conserved between the clocks of mammals, fungi, and plants. We now establish sumoylation, the posttranslational modification of target proteins by the covalent attachment of the small ubiquitin-like modifier protein SUMO, as a novel mechanism regulating key clock properties in the model plant Arabidopsis. Using 2 different approaches, we show that mutant plant lines with decreased or increased levels of global sumoylation exhibit shortened or lengthened circadian period, respectively. One known functional role of sumoylation is to protect the proteome from temperature stress. The circadian clock is characterized by temperature compensation, meaning that proper timekeeping is ensured over the full range of physiologically relevant temperatures. Interestingly, we observed that the period defects in sumoylation mutant plants are strongly differential across temperature. Increased global sumoylation leads to undercompensation of the clock against temperature and decreased sumoylation to overcompensation, implying that sumoylation buffers the plant clock system against differential ambient temperature

    Three novel components of the human exosome

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    Contains fulltext : 186951.pdf (publisher's version ) (Open Access)The yeast exosome is a complex of 3' --> 5' exoribonucleases. Sequence analysis identified putative human homologues for exosome components, although several were found only as expressed sequence tags. Here we report the cloning of full-length cDNAs, which encode putative human homologues of the Rrp40p, Rrp41p, and Rrp46p components of the exosome. Recombinant proteins were expressed and used to raise rabbit antisera. In Western blotting experiments, these decorated HeLa cell proteins of the predicted sizes. All three human proteins were enriched in the HeLa cells nucleus and nucleolus, but were also clearly detected in the cytoplasm. Size exclusion chromatography revealed that hRrp40p, hRrp41p, and hRrp46p were present in a large complex. This cofractionated with the human homologues of other exosome components, hRrp4p and PM/Scl-100. Anti-PM/Scl-positive patient sera coimmunoprecipitated hRrp40p, hRrp41p, and hRrp46p demonstrating their physical association. The immunoprecipitated complex exhibited 3' --> 5' exoribonuclease activity in vitro. hRrp41p was expressed in yeast and shown to suppress the lethality of genetic depletion of yeast Rrp41p. We conclude that hRrp40p, hRrp41p, and hRrp46p represent novel components of the human exosome complex

    The interactions of age, genetics, and disease severity on tacrolimus dosing requirements after pediatric kidney and liver transplantation

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    In children, data on the combined impact of age, genotype, and disease severity on tacrolimus (TAC) disposition are scarce. The aim of this study was to evaluate the effect of these covariates on tacrolimus dose requirements in the immediate post-transplant period in pediatric kidney and liver recipients. Data were retrospectively collected describing tacrolimus disposition, age, CYP3A5 and ABCB1 genotype, and pediatric risk of mortality (PRISM) scores for up to 14 days post-transplant in children receiving liver and renal transplants. Initial TAC dosing was equal in all patients and adjusted using therapeutic drug monitoring. We determined the relationship between covariates and tacrolimus disposition. Forty-eight kidney and 42 liver transplant recipients (median ages 11.5 and 1.5 years, ranges 1.5-17.7 and 0.05-14.8 years, respectively) received TAC post-transplant. In both transplant groups, younger children (< 5 years) needed higher TAC doses than older children [kidney: 0.15 (0.07-0.35) vs. 0.09 (0.02-0.20) mg/kg/12h, p = 0.046, liver: 0.12 (0.04-0.32) vs. 0.09 (0.01-0.18) mg/kg/12h, p = 0.038]. In kidney but not liver transplants, CYP3A5 expressors needed significantly higher TAC doses than nonexpressors [0.15 (0.07-0.20) vs. 0.09 (0.02-0.35) mg/kg/12h, P = 0.001]. In these patients, age and CYP3A5 genotype were independently associated with TAC dosing requirement. In liver, but not kidney transplant patients, homozygous ABCB1 T-T-T haplotype carriers needed higher TAC doses than noncarriers [0.26 (0.15-0.32) vs. 0.11 (0.01-0.25) mg/kg/12h, p = 0.013]. CYP3A5 genotype may explain variation in tacrolimus disposition early after transplant in pediatric kidney recipients, independent of age-related variation. In contrast, in pediatric liver recipients, variation in tacrolimus disposition appears related to age and ABCB1 genotype. These findings illustrate the importance of the interplay among age, genotype, and transplant organ on tacrolimus disposition

    An Update on MyoD Evolution in Teleosts and a Proposed Consensus Nomenclature to Accommodate the Tetraploidization of Different Vertebrate Genomes

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    DJM was supported by a Natural Environment Research Council studentship (NERC/S/A/2004/12435).Background: MyoD is a muscle specific transcription factor that is essential for vertebrate myogenesis. In several teleost species, including representatives of the Salmonidae and Acanthopterygii, but not zebrafish, two or more MyoD paralogues are conserved that are thought to have arisen from distinct, possibly lineage-specific duplication events. Additionally, two MyoD paralogues have been characterised in the allotetraploid frog, Xenopus laevis. This has lead to a confusing nomenclature since MyoD paralogues have been named outside of an appropriate phylogenetic framework. Methods and Principal Findings: Here we initially show that directly depicting the evolutionary relationships of teleost MyoD orthologues and paralogues is hindered by the asymmetric evolutionary rate of Acanthopterygian MyoD2 relative to other MyoD proteins. Thus our aim was to confidently position the event from which teleost paralogues arose in different lineages by a comparative investigation of genes neighbouring myod across the vertebrates. To this end, we show that genes on the single myod-containing chromosome of mammals and birds are retained in both zebrafish and Acanthopterygian teleosts in a striking pattern of double conserved synteny. Further, phylogenetic reconstruction of these neighbouring genes using Bayesian and maximum likelihood methods supported a common origin for teleost paralogues following the split of the Actinopterygii and Sarcopterygii. Conclusion: Our results strongly suggest that myod was duplicated during the basal teleost whole genome duplication event, but was subsequently lost in the Ostariophysi ( zebrafish) and Protacanthopterygii lineages. We propose a sensible consensus nomenclature for vertebrate myod genes that accommodates polyploidization events in teleost and tetrapod lineages and is justified from a phylogenetic perspective.Publisher PDFPeer reviewe

    Standardised data on initiatives—STARDIT: Beta version

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    Background and objective: There is currently no standardised way to share information across disciplines about initiatives, including fields such as health, environment, basic science, manufacturing, media and international development. All problems, including complex global problems such as air pollution and pandemics require reliable data sharing between disciplines in order to respond effectively. Current reporting methods also lack information about the ways in which different people and organisations are involved in initiatives, making it difficult to collate and appraise data about the most effective ways to involve different people. The objective of STARDIT (Standardised Data on Initiatives) is to address current limitations and inconsistencies in sharing data about initiatives. The STARDIT system features standardised data reporting about initiatives, including who has been involved, what tasks they did, and any impacts observed. STARDIT was created to help everyone in the world find and understand information about collective human actions, which are referred to as ‘initiatives’. STARDIT enables multiple categories of data to be reported in a standardised way across disciplines, facilitating appraisal of initiatives and aiding synthesis of evidence for the most effective ways for people to be involved in initiatives. This article outlines progress to date on STARDIT; current usage; information about submitting reports; planned next steps and how anyone can become involved. Method: STARDIT development is guided by participatory action research paradigms, and has been co-created with people from multiple disciplines and countries. Co-authors include cancer patients, people affected by rare diseases, health researchers, environmental researchers, economists, librarians and academic publishers. The co-authors also worked with Indigenous peoples from multiple countries and in partnership with an organisation working with Indigenous Australians. Results and discussion: Over 100 people from multiple disciplines and countries have been involved in co-designing STARDIT since 2019. STARDIT is the first open access web-based data-sharing system which standardises the way that information about initiatives is reported across diverse fields and disciplines, including information about which tasks were done by which stakeholders. STARDIT is designed to work with existing data standards. STARDIT data will be released into the public domain (CC0) and integrated into Wikidata; it works across multiple languages and is both human and machine readable. Reports can be updated throughout the lifetime of an initiative, from planning to evaluation, allowing anyone to be involved in reporting impacts and outcomes. STARDIT is the first system that enables sharing of standardised data about initiatives across disciplines. A working Beta version was publicly released in February 2021 (ScienceforAll.World/STARDIT). Subsequently, STARDIT reports have been created for peer-reviewed research in multiple journals and multiple research projects, demonstrating the usability. In addition, organisations including Cochrane and Australian Genomics have created prospective reports outlining planned initiatives. Conclusions: STARDIT can help create high-quality standardised information on initiatives trying to solve complex multidisciplinary global problems

    Display of probability densities for data from a continuous distribution

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    Based on cumulative distribution functions, Fourier series expansion and Kolmogorov tests, we present a simple method to display probability densities for data drawn from a continuous distribution. It is often more efficient than using histograms.Comment: 5 pages, 4 figures, presented at Computer Simulation Studies XXIV, Athens, GA, 201
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