Object-oriented data modeling

The object-oriented paradigm models local behavior, and to a lesser extent, the structure of a problem. Semantic data models describe structure and semantics. This thesis unifies the behavioral focus of the object-oriented paradigm with the structural and semantic focus of semantic data models. The approach contains expressive abstractions to model static and derived data, semantics, and behavior. The abstractions keep the data model closer to the problem domain, and can be translated into a relational (or other) implementation. The paper makes six contributions. First, a comprehensive set of data structuring abstractions are described. Second, the abstractions are compared to the entity-relationship and relational models. Third, semantic information inherent in the functional representation of the abstractions is identified. Fourth, a set of behavioral abstractions are described. Fifth, an algorithm that describes the dynamics between mathematically derived attributes of cooperating objects is presented. Sixth, weaknesses of object-oriented programming languages are identified

Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions

We study the beam-energy and system-size dependence of \phi meson production (using the hadronic decay mode \phi -- K+K-) by comparing the new results from Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the transverse momentum distributions for \phi mesons are observed to be similar in yield and shape for Cu+Cu and Au+Au colliding systems with similar average numbers of participating nucleons. The \phi meson yields in nucleus-nucleus collisions, normalised by the average number of participating nucleons, are found to be enhanced relative to those from p+p collisions with a different trend compared to strange baryons. The enhancement for \phi mesons is observed to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.Comment: 20 pages and 5 figure

QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Oil impacts on coastal wetlands: Implications for the Mississippi River delta ecosystem after the deepwater horizon oil spill

On 20 April 2010, the Deepwater Horizon explosion, which released a US governmentestimated 4.9 million barrels of crude oil into the Gulf of Mexico, was responsible for the death of 11 oil workers and, possibly, for an environmental disaster unparalleled in US history. For 87 consecutive days, the Macondo well continuously released crude oil into the Gulf of Mexico. Many kilometers of shoreline in the northern Gulf of Mexico were affected, including the fragile and ecologically important wetlands of Louisiana\u27s Mississippi River Delta ecosystem. These wetlands are responsible for a third of the nation\u27s fish production and, ironically, help to protect an energy infrastructure that provides a third of the nations oil and gas supply. Here, we provide a basic overview of the chemistry and biology of oil spills in coastal wetlands and an assessment of the potential and realized effects on the ecological condition of the Mississippi River Delta and its associated flora and fauna. © 2012 by American Institute of Biological Sciences

Genome of the Bacterium Streptococcus pneumoniae Strain R6

Streptococcus pneumoniae is among the most significant causes of bacterial disease in humans. Here we report the 2,038,615-bp genomic sequence of the gram-positive bacterium S. pneumoniae R6. Because the R6 strain is avirulent and, more importantly, because it is readily transformed with DNA from homologous species and many heterologous species, it is the principal platform for investigation of the biology of this important pathogen. It is also used as a primary vehicle for genomics-based development of antibiotics for gram-positive bacteria. In our analysis of the genome, we identified a large number of new uncharacterized genes predicted to encode proteins that either reside on the surface of the cell or are secreted. Among those proteins there may be new targets for vaccine and antibiotic development