2,172 research outputs found
Bottom-quark associated Higgs-boson production: reconciling the four- and five-flavour scheme approach
The main arguments in the discussion of the proper treatment of the total
inclusive cross section for bottom-quark associated Higgs-boson production are
briefly reviewed. A simple and pragmatic formula for the combination of the
so-called four- and five-flavour schemes is suggested, including the treatment
of the respective theory error estimates. The numerical effects of this
matching formula are discussed.Comment: 8 pages, 4 figure
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Analyzing Data Citations to Assess the Scientific and Societal Value of Scientific Data
Stakeholders in the creation, distribution, support, funding, and use of scientific data can benefit by assessing the value that the data have for society and science. For decades, the scientific community has used citations of articles in the published scientific literature as one of the primary measures for evaluating the performance and productivity of scientists, departments, institutions, and scientific disciplines. Similarly, citations of scientific data in the published literature may be useful for tracking and comparing the value of the scientific data and the contributions of individuals, projects, programs, and organizations to the data’s development and use. Citation analysis can contribute to planning for future data collection, development, distribution, and preservation efforts. The release of new data citation indexes and more widespread adoption of unique data identifiers and automated attribution mechanisms have the potential to improve significantly the capabilities for analyzing citations of scientific data. In addition, ongoing developments in the systems and capabilities for disseminating data, along with education and workforce training on the importance of data attribution and on techniques for data citation, can improve practices for citing scientific data. Such practices need to lead not only to better aggregate statistics about data citation, but also to improved characterization and understanding of the impact of data use with respect to the benefits for science and society. Analyses of citations in the scientific literature were conducted for data that were distributed by an interdisciplinary scientific data center during a five-year period (1997–2011), to identify the scientific fields represented by the journals and books in which the data were cited. Secondary citation analysis also was conducted for a sample of scientific publications that used the data extensively to identify the potential impact of the data on the scientific fields represented by those journals. Furthermore, an initial analysis was conducted of citations that appeared in non-peer-reviewed publications and the popular media to assess the potential policy and educational impacts of these data. The initial results of these analyses demonstrate the significant challenges that remain for consistent, quantitative assessment of the value of scientific data to both science and society
Extreme vorticity events in turbulent Rayleigh-Bénard convection from stereoscopic measurements and reservoir computing
High-amplitude events of the out-of-plane vorticity component ωz are analyzed by stereoscopic particle image velocimetry (PIV) in the bulk region of turbulent Rayleigh-Bénard convection in air. The Rayleigh numbers Ra vary from 1.7×104 to 5.1×105. The experimental investigation is connected with a comprehensive statistical analysis of long-term time series of ωz and individual velocity derivatives ∂ui/∂xj. A statistical convergence for derivative moments up to an order of 6 is demonstrated. Our results are found to agree well with existing high-resolution direct numerical simulation data in the same range of parameters, including the extreme vorticity events that appear in the far exponential tails of the corresponding probability density functions. The transition from Gaussian to non-Gaussian velocity derivative statistics in the bulk of a convection flow is confirmed experimentally. The experimental data are used to train a reservoir computing model, one implementation of a recurrent neural network, to reproduce highly intermittent experimental time series of the vorticity and thus reconstruct extreme out-of-plane vorticity events. After training the model with high-resolution PIV data, the machine learning model is run with sparsely seeded, continually available, and unseen measurement data in the reconstruction phase. The dependence of the reconstruction quality on the sparsity of the partial observations is also documented. Our latter result paves the way to machine-learning-assisted experimental analyses of small-scale turbulence for which time series of missing velocity derivatives can be provided by generative algorithms
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Measuring the Interdisciplinary Impact of Using Geospatial Data with Remote Sensing Data
Various disciplines offer benefits to society by contributing to the scientific progress that informs the knowledge and decisions that improve the lives, safety, and conditions of people around the globe. In addition to disciplines within the natural sciences, other disciplines, including those in the social, health, and computer sciences, provide benefits to society by collecting, preparing, and analyzing data in the process of conducting research. Preparing geospatial environmental and socioeconomic data together with remote sensing data from satellite-based instruments for wider use by heterogeneous communities of users increases the potential impact of these data by enabling their use in different application areas and sectors of society. Furthermore, enabling wider use of scientific data can bring to bear resources and expertise that will improve reproducibility, quality, methodological transparency, interoperability, and improved understanding by diverse communities of users. In line with its commitment to open data, the NASA Socioeconomic Data and Applications Center (SEDAC), which focuses on human interactions in the environment, curates and disseminates freely and publicly available geospatial data for use across many disciplines and societal benefit areas. We describe efforts to broaden the use of SEDAC data and to publicly document their impact, assess the interdisciplinary impact of the use of SEDAC data with remote sensing data, and characterize these impacts in terms of their influence across disciplines by analyzing citations of geospatial data with remote sensing data within scientific journals
Information-theoretical meaning of quantum dynamical entropy
The theory of noncommutative dynamical entropy and quantum symbolic dynamics
for quantum dynamical systems is analised from the point of view of quantum
information theory. Using a general quantum dynamical system as a communication
channel one can define different classical capacities depending on the
character of resources applied for encoding and decoding procedures and on the
type of information sources. It is shown that for Bernoulli sources the
entanglement-assisted classical capacity, which is the largest one, is bounded
from above by the quantum dynamical entropy defined in terms of operational
partitions of unity. Stronger results are proved for the particular class of
quantum dynamical systems -- quantum Bernoulli shifts. Different classical
capacities are exactly computed and the entanglement-assisted one is equal to
the dynamical entropy in this case.Comment: 6 page
Pediatric Coronary Allograft Vasculopathy—A Review of Pathogenesis and Risk Factors
Coronary allograft vasculopathy is the current leading cause for late graft loss following cardiac transplantation. Its pathogenesis is multifactorial, including immune, constitutional and genetic factors, metabolism, infection, as well as potential injury from routine immunosuppressive therapy. Children represent a patient group with unique differences: their pretransplant history rarely includes ischemic heart disease and risk factors for atherosclerotic heart disease, but many are presensitized from use of allograft material during reconstructive cardiac surgeries. Compared with older children and adults, infants and young children show significantly lower rates of graft vasculopathy that may be related to the relative immaturity of their immune system. This review summarizes the current concepts of coronary allograft vasculopathy derived mainly from animal models and adult clinical observations. It provides an overview of confirmed risk factors and explains their interactions. The characteristics and unique clinical findings among pediatric transplant recipients will be explored within the context of recent, albeit limited, scientific investigations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92455/1/chd601.pd
Staying loyal or leaving the party? How open and extrovert personality traits help explain vote switching
Why are some citizens more likely to change their vote choice? Bert Bakker, Robert Klemmensen, Asbjørn Sonne Nørgaard and Gijs Schumacher show that vote switching is associated with citizen’s personality traits. Looking at UK and Denmark, they find that openness helps explain vote switching in both countries. In Denmark having a more extrovert personality is associated with party loyalty, but this does not hold for the UK
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