Replica Selection in the Globus Data Grid

The Globus Data Grid architecture provides a scalable infrastructure for the management of storage resources and data that are distributed across Grid environments. These services are designed to support a variety of scientific applications, ranging from high-energy physics to computational genomics, that require access to large amounts of data (terabytes or even petabytes) with varied quality of service requirements. By layering on a set of core services, such as data transport, security, and replica cataloging, one can construct various higher-level services. In this paper, we discuss the design and implementation of a high-level replica selection service that uses information regarding replica location and user preferences to guide selection from among storage replica alternatives. We first present a basic replica selection service design, then show how dynamic information collected using Globus information service capabilities concerning storage system properties can help improve and optimize the selection process. We demonstrate the use of Condor's ClassAds resource description and matchmaking mechanism as an efficient tool for representing and matching storage resource capabilities and policies against application requirements.Comment: 8 pages, 6 figure

A Comparative Analysis of Kentucky State Parks

This study is a survey of the Kentucky State Park system as it exists today. Investigations were directed primarily to factors which influence attendance at Kentucky\u27s parks and to the development of a formula for use in determining possible expansion rates for these parks

Determining the phylogenetic relationships among the northern pike (Esox lucius), the muskellunge (Esox masquinongy), and the silver pike

Prioritization of taxa has become a necessity due to limited resources available for conservation. Conservation efforts are often concentrated on those threatened and endangered species with the highest taxonomic importance. The silver pike is a rare game fish, often accounting for less than 1% of a total pike population where it is found. Although silver pike are normally found in association with northern pike, they have distinct morphological characteristics and have not been shown to hybridize with the northern pike. Still, many fisheries biologists consider the silver pike to be a color variant of the northern pike, and to date the silver pike has not been assigned to a taxonomic unit. This study employs the use of a molecular marker on the mitochondrial genome to determine the phylogenetic relationships between the northern pike, silver pike and muskellunge. Mitochondrial DNA was amplified from individual scales, cloned into the pCR®2.1 vector and sequenced at the Marshall Core Facility. The sequences were aligned using ClustalX (Thompson et al., Nuc. Acids Res. 22:4673), and phylogenetic distances and tree topologies were inferred using the programs of the PHYLIP package (Felsenstein, Cladistics 5:164). Sequence data was sufficient to distinguish between the northern pike and muskellunge. No sequence variation was found between the silver pike and northern pike. Resulting tree topologies were unable to distinguish between the silver pike and northern pike in all cases. Molecular data supports the hypothesis that the silver pike is a color variant of the northern pike and not a separate species

The Anatomy of the Grid - Enabling Scalable Virtual Organizations

"Grid" computing has emerged as an important new field, distinguished from conventional distributed computing by its focus on large-scale resource sharing, innovative applications, and, in some cases, high-performance orientation. In this article, we define this new field. First, we review the "Grid problem," which we define as flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources-what we refer to as virtual organizations. In such settings, we encounter unique authentication, authorization, resource access, resource discovery, and other challenges. It is this class of problem that is addressed by Grid technologies. Next, we present an extensible and open Grid architecture, in which protocols, services, application programming interfaces, and software development kits are categorized according to their roles in enabling resource sharing. We describe requirements that we believe any such mechanisms must satisfy, and we discuss the central role played by the intergrid protocols that enable interoperability among different Grid systems. Finally, we discuss how Grid technologies relate to other contemporary technologies, including enterprise integration, application service provider, storage service provider, and peer-to-peer computing. We maintain that Grid concepts and technologies complement and have much to contribute to these other approaches.Comment: 24 pages, 5 figure

Conductivity of Paired Composite Fermions

We develop a phenomenological description of the nu=5/2 quantum Hall state in which the Halperin-Lee-Read theory of the half-filled Landau level is combined with a p-wave pairing interaction between composite fermions (CFs). The electromagnetic response functions for the resulting mean-field superconducting state of the CFs are calculated and used in an RPA calculation of the q and omega dependent longitudinal conductivity of the physical electrons, a quantity which can be measured experimentally

Biogenic gas nanostructures as ultrasonic molecular reporters.

Ultrasound is among the most widely used non-invasive imaging modalities in biomedicine, but plays a surprisingly small role in molecular imaging due to a lack of suitable molecular reporters on the nanoscale. Here, we introduce a new class of reporters for ultrasound based on genetically encoded gas nanostructures from microorganisms, including bacteria and archaea. Gas vesicles are gas-filled protein-shelled compartments with typical widths of 45-250 nm and lengths of 100-600 nm that exclude water and are permeable to gas. We show that gas vesicles produce stable ultrasound contrast that is readily detected in vitro and in vivo, that their genetically encoded physical properties enable multiple modes of imaging, and that contrast enhancement through aggregation permits their use as molecular biosensors

Physical activity and environment programme guidance : fieldwork report

This quick reference guide presents the recommendations on &lsquo;Promoting and creating built or natural environments that encourage and support physical activity&rsquo;. It is for NHS and other professionals who have a direct or indirect role in &ndash; and responsibility for &ndash; the built or natural environment. This includes those working in local authorities and the education, community, voluntary and private sectors. It may also be of interest to members of the public. The guidance offers the first national, evidence-based recommendations on how to improve the physical environment to encourage physical activity. It demonstrates the importance of such improvements and the need to evaluate how they impact on the public&rsquo;s health.<br /

Occupational and non-occupational physical activity and the social determinants of physical activity : results from the Health Survey for England

Background: This article aims to examine the relative contribution of occupational activity to English adults&rsquo; meeting of government recommendations for physical activity (PA). Methods: Data were extracted from a cross-sectional survey of householders in the UK via the Health Survey for England.1 In total, 14,018 adult participants were included in the analysis. Multivariate logistic regression was used to examine the odds of achieving PA recommendations with and without including occupational activity and to examine the contribution of gender and social and demographic characteristics. Results: When occupational PA was included, 36% of men and 25% of women were active at the recommended level. Once occupational PA was removed, these proportions were 23% and 19%, respectively. These results were socially patterned, most notably by age and gender.Conclusions: Occupational PA provides a substantial contribution to those meeting the government target for PA. <br /

Technologies for Ubiquitous Supercomputing: A Java Interface to the Nexus Communication system

We use the term ubiquitous supercomputing to refer to systems that integrate low- and mid-range computing systems, advanced networks and remote high-end computers with the goal of enhancing the computational power accessible from local environments. Such systems promise to enable new applications in areas as diverse as smart instruments and collaborative environments. However, they also demand tools for transporting code between computers and for establishing flexible, dynamic communication structures. In this article, we propose that these requirements be satisfied by introducing Java classes that implement the global pointer and remote service request mechanisms defined by a communication library called Nexus. Java supports transportable code; Nexus provides communication support and represents the core communication framework for Globus, a project building infrastructure for ubiquitous supercomputing. We explain how this NexusJava library is implemented and illustrate its use with examples