84 research outputs found

    Bounded Bessel Processes and Ferrari-Spohn Diffusions

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    We introduce a new diffusion process which arises as the n→∞n\to\infty limit of a Bessel process of dimension d≄2d \ge 2 conditioned upon remaining bounded below one until time nn. In addition to being interesting in its own right, we argue that the resulting diffusion process is a natural hard edge counterpart to the Ferrari-Spohn diffusion of arXiv:math/0308242. In particular, we show that the generator of our new diffusion has the same relation to the Sturm-Liouville problem for the Bessel operator that the Ferrari-Spohn diffusion does to the corresponding problem for the Airy operator.Comment: 8 page

    Does public transit use enhance the economic efficiency of urban areas?

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    JTLU vol 5, no 3, pp 53-67 (2012)This paper explores the relationship between the scale of public transit services in large urban areas of the United States and the efficiency of those economies, with efficiency measured by commercial office rents. Panel regressions are estimated in which real office rent is the left-hand variable. The key right-hand variable is per-capita transit use. Other right-hand variables include demand for office space, office vacancy rate, average real wage, and unemployment rate. Two-stage least-squares equations are estimated to deal with possible simultaneity between office rents and transit use. Results indicate a positive relationship between public transit use and office rents. The relationship is positive and significant in urban areas with higher concentrations of office space in the central business district, and nonexistent in urban areas with lower concentrations. The estimated dollar impact of transit use on office rents is small

    A Soluble String Theory of Hadrons

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    We consider Penrose limits of the Klebanov-Strassler and Maldacena-Nunez holographic duals to N =1 supersymmetric Yang-Mills. By focusing in on the IR region we obtain exactly solvable string theory models. These represent the nonrelativistic motion and low-lying excitations of heavy hadrons with mass proportional to a large global charge. We argue that these hadrons, both physically and mathematically, take the form of heavy nonrelativistic strings; we term them "annulons." A simple toy model of a string boosted along a compact circle allows us considerable insight into their properties. We also calculate the Wilson loop carrying large global charge and show the effect of confinement is quadratic, not linear, in the string tension.Comment: 40 pages, 1 figure; v2: typos correcte

    High content live cell imaging for the discovery of new antimalarial marine natural products

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    <p>Abstract</p> <p>Background</p> <p>The human malaria parasite remains a burden in developing nations. It is responsible for up to one million deaths a year, a number that could rise due to increasing multi-drug resistance to all antimalarial drugs currently available. Therefore, there is an urgent need for the discovery of new drug therapies. Recently, our laboratory developed a simple one-step fluorescence-based live cell-imaging assay to integrate the complex biology of the human malaria parasite into drug discovery. Here we used our newly developed live cell-imaging platform to discover novel marine natural products and their cellular phenotypic effects against the most lethal malaria parasite, <it>Plasmodium falciparum</it>.</p> <p>Methods</p> <p>A high content live cell imaging platform was used to screen marine extracts effects on malaria. Parasites were grown <it>in vitro </it>in the presence of extracts, stained with RNA sensitive dye, and imaged at timed intervals with the BD Pathway HT automated confocal microscope.</p> <p>Results</p> <p>Image analysis validated our new methodology at a larger scale level and revealed potential antimalarial activity of selected extracts with a minimal cytotoxic effect on host red blood cells. To further validate our assay, we investigated parasite's phenotypes when incubated with the purified bioactive natural product bromophycolide A. We show that bromophycolide A has a strong and specific morphological effect on parasites, similar to the ones observed from the initial extracts.</p> <p>Conclusion</p> <p>Collectively, our results show that high-content live cell-imaging (HCLCI) can be used to screen chemical libraries and identify parasite specific inhibitors with limited host cytotoxic effects. All together we provide new leads for the discovery of novel antimalarials.</p

    Long-lived magnetism on chondrite parent bodies

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    publisher: Elsevier articletitle: Long-lived magnetism on chondrite parent bodies journaltitle: Earth and Planetary Science Letters articlelink: http://dx.doi.org/10.1016/j.epsl.2017.07.035 content_type: article copyright: © 2017 The Authors. Published by Elsevier B.V.© 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). The attached file is the published version of the article

    Commitment zu aktivem Daten- und -softwaremanagement in großen ForschungsverbĂŒnden

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    Wir erkennen die Wichtigkeit von Forschungsdaten und -software fĂŒr unsere Forschungsprozesse an und ordnen die Veröffentlichung von Forschungsdaten und -software als wesentlichen Bestandteil der wissenschaftlichen PublikationstĂ€tigkeit ein. DafĂŒr unterstĂŒtzen wir als Verbund unsere Forschenden im Umgang mit Daten und Software nach den FAIR-Prinzipien in Einvernehmen mit dem DFG-Kodex “Leitlinien zur Sicherung guter wissenschaftlicher Praxis”. In Zusammenarbeit mit unseren Institutionen und Fachcommunities stellen wir adĂ€quate Forschungsdatenmanagement-Werkzeuge und -Dienste bereit und befĂ€higen unsere Forschenden zum Umgang damit. Dabei bauen wir vorzugsweise auf existierenden Angeboten auf und bemĂŒhen uns im Gegenzug um deren Anpassung an unsere BedĂŒrfnisse. Wir streben Maßnahmen fĂŒr die Definition und Sicherstellung der QualitĂ€t unserer Forschungsdaten und -software an. Wir verwenden vorzugsweise existierende Daten-/Metadatenstandards und vernetzen uns nach Möglichkeit fĂŒr die Erstellung und Implementierung neuer Standards mit entsprechenden nationalen und internationalen Initiativen. Wir verfolgen die Entwicklungen im Bereich des Forschungsdaten- und -softwaremanagements und prĂŒfen neu entstehende Empfehlungen und Richtlinien zeitnah auf ihre Umsetzbarkeit

    Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

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    Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs

    Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

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