7,515 research outputs found

    Quick-look guide to the crustal dynamics project's data information system

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    Described are the contents of the Crustal Dynamics Project Data Information System (DIS) and instructions on the use of this facility. The main purpose of the DIS is to store all geodetic data products acquired by the Project in a central data bank and to maintain information about the archive of all Project-related data. Access and use of the DIS menu-driven system is described as well as procedures for contacting DIS staff and submitting data requests

    An Integrated and Collaborative Approach for NASA Earth Science Data

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    Earth science research requires coordination and collaboration across multiple disparate science domains. Data systems that support this research are often as disparate as the disciplines that they support. These distinctions can create barriers limiting access to measurements, which could otherwise enable cross-discipline Earth science. NASA's Earth Observing System Data and Information System (EOSDIS) is continuing to bridge the gap between discipline-centric data systems with a coherent and transparent system of systems that offers up to date and engaging science related content, creates an active and immersive science user experience, and encourages the use of EOSDIS earth data and services. The new Earthdata Coherent Web (ECW) project encourages cohesiveness by combining existing websites, data and services into a unified website with a common look and feel, common tools and common processes. It includes cross-linking and cross-referencing across the Earthdata site and NASA's Distributed Active Archive Centers (DAAC), and by leveraging existing EOSDIS Cyber-infrastructure and Web Service technologies to foster re-use and to reduce barriers to discovering Earth science data (http://earthdata.nasa.gov)

    Symmetries of differential-difference dynamical systems in a two-dimensional lattice

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    Classification of differential-difference equation of the form u¨nm=Fnm(t,{upq}(p,q)Γ)\ddot{u}_{nm}=F_{nm}\big(t, \{u_{pq}\}|_{(p,q)\in \Gamma}\big) are considered according to their Lie point symmetry groups. The set Γ\Gamma represents the point (n,m)(n,m) and its six nearest neighbors in a two-dimensional triangular lattice. It is shown that the symmetry group can be at most 12-dimensional for abelian symmetry algebras and 13-dimensional for nonsolvable symmetry algebras.Comment: 24 pages, 1 figur

    Possible Single Resonant Production of the Fourth Generation Charged Leptons at γe\gamma e Colliders

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    Single resonant productions of the fourth standard model generation charged lepton via anomalous interactions at gamma e colliders based on future linear e^+ e^- colliders with 500 GeV and 1 TeV center of mass energies are studied. Signatures of γe4eγ\gamma e\to \ell_4\to e\gamma and γe4eZ\gamma e\to \ell_4\to eZ anomalous processes followed by the hadronic and leptonic decay of the Z boson and corresponding standard model backgrounds are discussed in details. The lowest necessary luminosities to observe these processes and the achievable values of the anomalous coupling strengths are determined.Comment: 9 pages, 6 figures, 4 table

    Grading Policy and Student Retention

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    This article discuses two policies that work at cross purposes to one another which university administrators and faculty works collaboratively with. Schools are actively resisting grade inflation trends while at the same time seeking to retain students. The article describes the borderline student, a category of at risk student often overlooked, yet numerous. It is found that academic performance was the highest ranked risk factor, accounting for approximately 20% of the variance, while behavior and coping skills was a distant second, accounting for only 6% of the risk factor variance. Borderline students can be efficiently rescued with modest outlays of additional institutional resources and are more likely to persist than students with less ability or more pernicious learning difficulties

    Status of the PICASSO Project

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    The Picasso project is a dark matter search experiment based on the superheated droplet technique. Preliminary runs performed at the Picasso Lab in Montreal have showed the suitability of this detection technique to the search for weakly interacting cold dark matter particles. In July 2002, a new phase of the project started. A batch of six 1-liter detectors with an active mass of approximately 40g was installed in a gallery of the SNO observatory in Sudbury, Ontario, Canada at a depth of 6,800 feet (2,070m). We give a status report on the new experimental setup, data analysis, and preliminary limits on spin-dependent neutralino interaction cross section.Comment: 3 pages, 2 figures. To appear in the Proceedings of the TAUP 2003 conference, 5-9 September, 2003, University of Washington, Seattle, US

    Spatial and temporal variation in macroparasite communities of three-spined stickleback

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    Patterns in parasite community structure are often observed in natural systems and an important question in parasite ecology is whether such patterns are repeatable across time and space. Field studies commonly look at spatial or temporal repeatability of patterns, but they are rarely investigated in conjunction. We use a large dataset on the macroparasites of the three-spined stickleback, Gasterosteus aculeatus L., collected from 14 locations on North Uist, Scotland over an 8-year period to investigate: (1) repeatability of patterns in parasite communities among populations and whether variation is consistent across years, (2) whether variation between years can be explained by climatic variation and progression of the season and (3) whether variation in habitat characteristics explain population differences. Differences in relative abundance and prevalence across populations were observed in a number of parasites investigated indicating a lack of consistency across years in numerous parasite community measures; however, differences between populations in the prevalence and abundance of some parasites were consistent throughout the study. Average temperature did not affect parasite community, and progression of the season was only significant for two of 13 community measures. Two of the six habitat characteristics investigated (pH and calcium concentration) significantly affected parasite presence
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