32,128 research outputs found

    Analog to digital conversion and processing of MSS data using a hybrid computer

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    There are no author-identified significant results in this report

    On the distribution of career longevity and the evolution of home run prowess in professional baseball

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    Statistical analysis is a major aspect of baseball, from player averages to historical benchmarks and records. Much of baseball fanfare is based around players exceeding the norm, some in a single game and others over a long career. Career statistics serve as a metric for classifying players and establishing their historical legacy. However, the concept of records and benchmarks assumes that the level of competition in baseball is stationary in time. Here we show that power-law probability density functions, a hallmark of many complex systems that are driven by competition, govern career longevity in baseball. We also find similar power laws in the density functions of all major performance metrics for pitchers and batters. The use of performance-enhancing drugs has a dark history, emerging as a problem for both amateur and professional sports. We find statistical evidence consistent with performance-enhancing drugs in the analysis of home runs hit by players in the last 25 years. This is corroborated by the findings of the Mitchell Report [1], a two-year investigation into the use of illegal steroids in major league baseball, which recently revealed that over 5 percent of major league baseball players tested positive for performance-enhancing drugs in an anonymous 2003 survey.Comment: 5 pages, 5 figures, 2-column revtex4 format. Revision has change of title, a figure added, and minor changes in response to referee comment

    Technical note On modifying the Arrhenius equation to compensate for temperature changes for reactions within biological systems

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    In this communiqué, we discuss the use of the Arrhenius relationship to describe the temperature dependence of reacting biological systems, such as those treating wastewater. We also discuss the use of the modified Arrhenius function, and those instances where its applicability is limited. We show that the error when using the modified relationship is 7% at 30°C, 15% at 40°C and 25% at 50°C. We conclude that whilst the modified relationship is acceptable at lower temperatures, in those applications where higher temperatures are reached (above 25°C) the error with using the relationship may not be acceptable. We present an Arrhenius equation for use in biological systems, which is applicable for all temperature ranges.Keywords: kinetics, biological processes, Arrhenius equatio

    How Sensitive are Di-Leptons from Rho Mesons to the High Baryon Density Region?

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    We show that the measurement of di-leptons might provide only a restricted view into the most dense stages of heavy ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as e.g. done at GSI-HADES and envisioned for FAIR-CBM, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high baryon density region of the heavy ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract di-leptons from transport simulations - i.e. shining, only vector mesons from final baryon resonance decays and instant emission of di-leptons and find a strong sensitivity on the method employed in particular at FAIR and SPS energies. It is shown explicitly that a restriction to rho meson (and therefore di-lepton) production only in final state baryon resonance decays provide a strong bias towards rather low baryon densities. The results presented are obtained from UrQMD v2.3 calculations using the standard set-up.Comment: 8 pages, 6 figures, expanded versio

    Methods for measuring the citations and productivity of scientists across time and discipline

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    Publication statistics are ubiquitous in the ratings of scientific achievement, with citation counts and paper tallies factoring into an individual's consideration for postdoctoral positions, junior faculty, tenure, and even visa status for international scientists. Citation statistics are designed to quantify individual career achievement, both at the level of a single publication, and over an individual's entire career. While some academic careers are defined by a few significant papers (possibly out of many), other academic careers are defined by the cumulative contribution made by the author's publications to the body of science. Several metrics have been formulated to quantify an individual's publication career, yet none of these metrics account for the dependence of citation counts and journal size on time. In this paper, we normalize publication metrics across both time and discipline in order to achieve a universal framework for analyzing and comparing scientific achievement. We study the publication careers of individual authors over the 50-year period 1958-2008 within six high-impact journals: CELL, the New England Journal of Medicine (NEJM), Nature, the Proceedings of the National Academy of Science (PNAS), Physical Review Letters (PRL), and Science. In comparing the achievement of authors within each journal, we uncover quantifiable statistical regularity in the probability density function (pdf) of scientific achievement across both time and discipline. The universal distribution of career success within these arenas for publication raises the possibility that a fundamental driving force underlying scientific achievement is the competitive nature of scientific advancement.Comment: 25 pages in 1 Column Preprint format, 7 Figures, 4 Tables. Version II: changes made in response to referee comments. Note: change in definition of "Paper shares.

    Host Plant Resistance of Cool-Season (C3) Turfgrasses to Above- and Belowground Feeding by Tipula paludosa (Diptera: Tipulidae)

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    Feeding on above- and belowground plant tissues by Tipula paludosa Meigen during the period of rapid growth from second to forth instars is highly damaging to cool-season (C3) turfgrasses. It may be possible to reduce this damage by identifying grass genotypes that increase host plant protection. This study examined the impacts of plant genotype, endophyte infection, and plant ontogeny on host plant and insect responses during whole-plant feeding by T. paludosa. A series of no-choice greenhouse trials were conducted with third instar crane flies to determine 1) host plant tolerance in terms of reductions to above- and belowground plant biomass, 2) antixenosis resistance impacting insect behavior (emigration), and 3) antibiosis resistance impacting insect growth. Results showed that insect infestation level was the primary factor influencing plant biomass reductions. Belowground tissues were more tolerant to feeding than were aboveground tissues, with tall fescues, Festuca arundinacea Schreber, being most resistant to aboveground biomass reduction. Host plant associations with intercellular fungal endophytes (E+) decreased insect weight gain and decreased insect movement, but did not increase host plant tolerance. Plant ontogeny affected this response with insect weight gain significantly decreased on young (28 d) growth E+ grasses but not on old (90 d) growth E+ grasses, however. Host plant genotype and plant ontogeny can have significant impacts to host plant tolerance and insect physiology for T. paludosa larva. Furthermore, plant-endophyte associations have apparent sublethal effects that impact insect fitness and may further enhance host plant protectio
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