337 research outputs found

    Artificial Intelligence Approach to the Determination of Physical Properties of Eclipsing Binaries. I. The EBAI Project

    Full text link
    Achieving maximum scientific results from the overwhelming volume of astronomical data to be acquired over the next few decades will demand novel, fully automatic methods of data analysis. Artificial intelligence approaches hold great promise in contributing to this goal. Here we apply neural network learning technology to the specific domain of eclipsing binary (EB) stars, of which only some hundreds have been rigorously analyzed, but whose numbers will reach millions in a decade. Well-analyzed EBs are a prime source of astrophysical information whose growth rate is at present limited by the need for human interaction with each EB data-set, principally in determining a starting solution for subsequent rigorous analysis. We describe the artificial neural network (ANN) approach which is able to surmount this human bottleneck and permit EB-based astrophysical information to keep pace with future data rates. The ANN, following training on a sample of 33,235 model light curves, outputs a set of approximate model parameters (T2/T1, (R1+R2)/a, e sin(omega), e cos(omega), and sin i) for each input light curve data-set. The whole sample is processed in just a few seconds on a single 2GHz CPU. The obtained parameters can then be readily passed to sophisticated modeling engines. We also describe a novel method polyfit for pre-processing observational light curves before inputting their data to the ANN and present the results and analysis of testing the approach on synthetic data and on real data including fifty binaries from the Catalog and Atlas of Eclipsing Binaries (CALEB) database and 2580 light curves from OGLE survey data. [abridged]Comment: 52 pages, accepted to Ap

    What Matters to Americans: Social, Political and Economic Values

    Full text link
    Societies are complex entities with competing and conflicting and supporting and reinforcing characteristics. This study, part of a multiyear project sponsored by the Australian Research Council (ARC) in conjunction with the University of Technology, Sydney and Melbourne Business School, seeks to chart the social, economic and political preferences of society, using a unique methodology that provides us with a more accurate and robust picture of how individuals, as citizens, make fundamental trade-offs about things of material interest to their society. The study was conducted in the United States of America with more than 2,800 participants, chosen to match the profile of the voting age population. Similar studies were conducted in the UK, Australia and Germany, providing data on more than 9,000 individuals.1 Examined were 16 categories of general social, economic and political issues that ranged from the local (for example, crime and public safety) to the global (for example, global security) along with 113 sub-issues that also varied from the local (for example, public transport and children’s schooling) to the global (for example, nuclear nonproliferation and third world debt). This information was linked to data on the population’s religious and political activities, its general demographics, and donating and volunteering activities with civil society organizations

    What Matters to Australians: Our Social, Political and Economic Values

    Full text link
    Societies are complex entities with competing and conflicting and supporting and reinforcing characteristics. This study, part of a multiyear project sponsored by the Australian Research Council (ARC) in conjunction with the University of Technology, Sydney and Melbourne Business School, seeks to chart the social, economic and political preferences of our society using a unique methodology that provides us with a more accurate and robust picture of how we, as citizens, make fundamental trade-offs about things of material interest to our society. The study was conducted in Australia with more than 1,500 participants chosen to match the profile of the voting age population. Similar studies were conducted in the UK, USA and Germany. Examined were 16 categories of general social, economic and political issues that ranged from the local (e.g., crime & public safety) to the global (e.g., global security) along with 113 subissues that also varied from the local (e.g., public transport and children’s schooling) to the global (e.g., nuclear non-proliferation and third world debt). This information was linked to information on the population’s religious and political activities, its general demographics, and donating and volunteering activities with civil society organisations

    What Matters to Citizens of the United Kingdom: Social, Political and Economic Values

    Full text link
    Societies are complex entities with competing and conflicting and supporting and reinforcing characteristics. This study, part of a multiyear project sponsored by the Australian Research Council (ARC) in conjunction with the University of Technology, Sydney and Melbourne Business School, seeks to chart the social, economic and political preferences of society using a unique methodology that provides us with a more accurate and robust picture of how individuals, as citizens, make fundamental trade-offs about things of material interest to their society. The study was conducted in the United Kingdom with nearly 1,700 participants, chosen to match the profile of the voting age population. Similar studies were conducted in Australia, the USA and Germany. Examined were 16 categories of general social, economic and political issues that ranged from the local (for example, crime and public safety) to the global (for example, global security) along with 113 sub-issues that also varied from the local (for example, public transport and children’s schooling) to the global (for example, nuclear non-proliferation and third world debt). This information was linked to data on the population’s religious and political activities, its general demographics, and donating and volunteering activities with civil society organisations

    Global molecular epidemiology of IMP-producing Enterobacteriaceae

    Get PDF
    International data on the molecular epidemiology of Enterobacteriaceae with IMP carbapenemases are lacking. We performed short read (Illumina) whole genomic sequencing on a global collection of 38 IMP-producing clinical Enterobacteriaceae (2008-14). IMP-producing Enterobacteriaceae (7 varieties within 11 class 1 integrons) were mainly present in South Pacific and Asia. Specific blaIMP containing integrons (In809 with blaIMP-4, In722 with blaIMP-6, In687 with blaIMP-14) were circulating among different bacteria in countries such as Australia, Japan and Thailand. In1312 with blaIMP-1 was present in K. pneumoniae from Japan and C. freundii from Brazil. Klebsiella pneumoniae (n=22) was the most common species; clonal complex (CC) 14 from the Philippines and Japan was the most common clone and contained In1310 with blaIMP-26 and In1321 with blaIMP-6. Enterobacter cloacae complex (n=9) consisted of E. hormaechei and E. cloacae cluster III. CC78 (from Taiwan) containing In73 with blaIMP-8, was the most common clone among E. cloacae complex. This study highlights the importance of surveillance programs using the latest molecular techniques in providing insight into the characteristics and global distribution of Enterobacteriaceae with blaIMPs.This work was supported by the John Mung Program from Kyoto University, Japan (Y.M.), a research grant from the Calgary Laboratory Services (#10015169; J.D.D.P) and federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services under Award Number U19AI110819 (MDA).http://aac.asm.org2017-10-30hb2017Medical Microbiolog

    Ecto-5′-nucleotidase and intestinal ion secretion by enteropathogenic Escherichia coli

    Get PDF
    Enteropathogenic Escherichia coli (EPEC) triggers a large release of adenosine triphosphate (ATP) from host intestinal cells and the extracellular ATP is broken down to adenosine diphosphate (ADP), AMP, and adenosine. Adenosine is a potent secretagogue in the small and large intestine. We suspected that ecto-5′-nucleotidase (CD73, an intestinal enzyme) was a critical enzyme involved in the conversion of AMP to adenosine and in the pathogenesis of EPEC diarrhea. We developed a nonradioactive method for measuring ecto-5′-nucleotidase in cultured T84 cell monolayers based on the detection of phosphate release from 5′-AMP. EPEC infection triggered a release of ecto-5′-nucleotidase from the cell surface into the supernatant medium. EPEC-induced 5′-nucleotidase release was not correlated with host cell death but instead with activation of phosphatidylinositol-specific phospholipase C (PI-PLC). Ecto-5′-nucleotidase was susceptible to inhibition by zinc acetate and by α,β-methylene-adenosine diphosphate (α,β-methylene-ADP). In the Ussing chamber, these inhibitors could reverse the chloride secretory responses triggered by 5′-AMP. In addition, α,β-methylene-ADP and zinc blocked the ability of 5′-AMP to stimulate EPEC growth under nutrient-limited conditions in vitro. Ecto-5′-nucleotidase appears to be the major enzyme responsible for generation of adenosine from adenine nucleotides in the T84 cell line, and inhibitors of ecto-5′-nucleotidase, such as α,β-methylene-ADP and zinc, might be useful for treatment of the watery diarrhea produced by EPEC infection
    • …
    corecore