863 research outputs found

    Gluon Fragmentation into Spin-Triplet S-Wave Quarkonium

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    The leading color-singlet contribution to the fragmentation function for a gluon to split into spin-triplet S-wave quarkonium is presented. In the case of charmonium, we find that this color-singlet term is always negligible compared to the leading color-octet contribution.Comment: 7 Latex page

    Subsidies and distorted markets: Do telecom subsidies affect competition?

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    There is general concern that producer subsidies distort competition. We examine a telecommunications subsidy system that transfers money from low cost regions to high cost regions of the U.S. Even though the system is designed to be competitively neutral, we find evidence that the system, combined with carrier of last resort policies, promotes cream skimming by entrants in low cost areas and deters entry in high cost areas, where incumbents are more likely than entrants to receive subsidies. We are unable to rule out the possibility that state regulatory policies favor incumbents in states that are net beneficiaries of the subsidy system.subsidies, Universal Service Fund, telecommunications, regulation

    The Formation of Ice Giants in a Packed Oligarchy: Instability and Aftermath

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    As many as 5 ice giants--Neptune-mass planets composed of 90% ice and rock and 10% hydrogen--are thought to form at heliocentric distances of 10-25 AU on closely packed orbits spaced ~5 Hill radii apart. Such oligarchies are ultimately unstable. Once the parent disk of planetesimals is sufficiently depleted, oligarchs perturb one another onto crossing orbits. We explore both the onset and the outcome of the instability through numerical integrations, including dynamical friction cooling of planets by a planetesimal disk whose properties are held fixed. To trigger instability and the ejection of the first ice giant in systems having an original surface density in oligarchs of Sigma ~ 1 g/cm^2, the disk surface density s must fall below 0.1 g/cm^2. Ejections are predominantly by Jupiter and occur within 10 Myr. To eject more than 1 oligarch requires s < 0.03 g/cm^2. Systems starting with up to 4 oligarchs in addition to Jupiter and Saturn can readily yield solar-system-like outcomes in which 2 surviving ice giants lie inside 30 AU and have their orbits circularized by dynamical friction. Our numerical simulations support the idea that planetary systems begin in more crowded and compact configurations, like those of shear-dominated oligarchies. In contrast to previous studies, we identify s < 0.1 Sigma as the regime relevant for understanding the evolution of the outer solar system, and we encourage future studies to concentrate on this regime while relaxing our assumption of a fixed planetesimal disk.Comment: Accepted to ApJ Jan 27. Incorporates comments from the referee and community at large. 15 pages, 14 figures, including 7 colo

    The Influence of Federal Laboratory R&D on Industrial Research

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    Over the past 60 years the United States has created the world's largest system of government laboratories. The impact of the laboratories on the private economy has been little studied though their research accounts for 14% of total U.S. R&D, more than the R&D of all colleges and universities combined. In this paper we study the influence of federal laboratory R&D on industrial research using a sample of industrial laboratories. In head-to-head comparisons with alternative measures, we find that Cooperative Research and Development Agreements or CRADAs, are the primary channel by which federal laboratories increase the patenting and R&D of industrial laboratories. With a CRADA industrial laboratories patent more, spend more on company-financed R&D and spend more of their own money on federal laboratories. Without a CRADA patenting stays about the same and only federally funded R&D increases, mostly because of direct subsidies by government. These results are consistent with the literature on endogenous R&D spillovers, which emphasizes that knowledge spills over when recipients work at making it spill over. CRADAs are legal agreements between federal laboratories and firms to work together on joint research. They are backed by real budgets and accompanied by cost sharing that could bind the parties together in joint research. Moreover, the CRADA instrument is the main form of such agreements. Thus, both in theory and in fact CRADAs may be more beneficial to firms than other public- private interactions, precisely because of the mutual effort that they require of firms and government laboratories.

    The Influence of Federal Laboratory R&D on Industrial Research

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    This paper studies the influence of R&D in the federal laboratory system, the world's largest, on firm research. Our results are based on a sample of 220 industrial research laboratories that work with a variety of federal laboratories and agencies and are owned by 115 firms in the chemicals, machinery, electrical equipment, and motor vehicles industries. Using an indicator of their importance to R&D managers, we find that Cooperative Research and Development Agreements or CRADAs dominate other channels of technology transfer from federal laboratories to firms. With a CRADA industry laboratories patent more, spend more on company-financed R&D, and devote more resources to their federal counterparts. Without this influence patenting stays about the same, and only federally funded R&D increases, mostly because of government support. The Stevenson-Wydler Act and amendments during the 1980s introduced CRADAs, which legally bind federal laboratories and firms together in joint research. In theory the agreements could capitalize on complementarities between public and private research. Our results support this perspective and suggest that CRADAs may be more beneficial to firms than other interactions with federal laboratories, precisely because of the mutual effort that they demand from both parties.

    Preparing Students For Class: A Clinical Trial Testing The Efficacy Between Multimedia Pre-lectures And Textbooks in an Economics Course

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    Motivating students to come prepared to class is often a futile exercise. The consequences are magnified as more instructors adopt the flipped classroom teaching model, in which students are expected to come to class with some knowledge of the material. This paper analyzed the implementation of a pedagogical tool that addresses this problem: multimedia pre-lectures. We tested the efficacy of pre-lectures on students with no prior exposure to college or AP-level economics using a controlled clinical experiment, focusing on introductory economics concepts. Students who had access to pre-lecture materials scored significantly higher on comprehension and retention than those with access only to textbooks

    COROSOLIC ACID: A SYNOPSIS ON ITS ANTICANCER PROPERTIES

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    Corosolic acid (CA) or 2β-hydroxyursolic acid is an ursane-type pentacyclic triterpene with a molecular formula of C30H48O4 and molecular weight of 473 g/mol. The 30-carbon skeleton and five six-membered rings (A−E) of CA are structurally similar to those of ursolic acid, asiatic acid, and 23-hydroxyl CA. CA was first isolated from the leaf of Lagerstroemia speciosa and later from the fruit of Crataegus pinnatifida. Although L. speciosa (Lythraceae) remains the most important source of CA, Rosaceae and Lamiaceae are the dominant families. This synopsis is focused on the anticancer properties of CA as recent studies have generated new and additional knowledge on its oncology. CA has antitumor, antiproliferative, and apoptotic activities against many types of human cancer cells (including some murine cancer cells), which are inhibited through different molecular mechanisms. Non-apoptotic cell death has also been reported. Depending on the type of cancer cells, the cytotoxicity of CA is comparable to ursolic acid, its analog. Currently, there are no studies on the structure-activity relationship of CA. In ursolic acid, which is structurally similar to CA, the −OH group at C-3 and the −COOH group at C-28 exhibited cytotoxic activity

    Vermonters’ Opinions on Low-Dose CT Lung Cancer Screening

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    Introduction: Lung cancer is the number one cause of cancer death among men and women in Vermont and the United States. Smoking increases the risk of lung cancer—nearly 90% of lung cancer is due to smoking. Frequently, lung cancers do not present clinically until they are advanced stage and therefore prognosis is poor. However, if detected early lung cancers are more operable and patients have better outcomes. In December 2013 the US Preventive Services Task Force released new guidelines for lung cancer screening among current and former smokers ages 55 to 80. It is recommended that current and former (within 15 years of quitting) smokers of 30 pack years receive an annual low-dose CT scan. The objective of this project was to assess the level of knowledge and attitudes towards lung cancer screening with low-dose CT scanning among Vermonters in the Burlington area.https://scholarworks.uvm.edu/comphp_gallery/1205/thumbnail.jp
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