403 research outputs found

    New Ways of Synthesizing Potential Pterin Anti-Fungal Drugs

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    Pterin based compounds have shown some promise as potential anti-fungal compounds; however, the low solubility of them in most organic solvents make the synthesis of these compounds tedious and difficult. Work is underway to do some of the steps of the synthesis in a different order to avoid the solubility issues. The goal is to be able to synthesize the final furan intermediate before adding the very insoluble pterin group in the final step to bypass any solubility issues that were encountered in synthesizing this molecule. First, the chlorinated furan intermediate underwent a reaction with sodium azide to convert the chlorine group on the furan into an azide group. Currently, work is being done on the second step, a DBU amidation to convert an ester to an amide group with a BOC protected amine

    Improving IS Service Quality

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    The growth of end-user computing has led to an awareness of the need to evaluate the quality of services provided by the information systems function. This paper discusses the two primary schools of thought or approaches concerning service quality. While the disconfirmation-based approach conceptualizes service quality as “similar to an attitude, the performance-based approach conceptualizes service quality as “attitude-based.” The literature concerning the application of both service quality approaches in an IS context are discussed and analyzed. Special attention is paid to the service orientation of IS employees as they relate to IS users. Prescriptions for improvements to the quality of IS service are suggested in four management areas: 1) service orientation of IS providers, 2) training/education of IS providers and IS users, 3) reward system for IS employees, and 4) linking IT strategy to business strategy. Lastly, SERVQUAL and SERVPERF are discussed as two quantitative measures of IS service quality

    Molecular systematics of the marine Dothideomycetes

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    Phylogenetic analyses of four nuclear genes, namely the large and small subunits of the nuclear ribosomal RNA, transcription elongation factor 1-alpha and the second largest RNA polymerase II subunit, established that the ecological group of marine bitunicate ascomycetes has representatives in the orders Capnodiales, Hysteriales, Jahnulales, Mytilinidiales, Patellariales and Pleosporales. Most of the fungi sequenced were intertidal mangrove taxa and belong to members of 12 families in the Pleosporales: Aigialaceae, Didymellaceae, Leptosphaeriaceae, Lenthitheciaceae, Lophiostomataceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae, Phaeosphaeriaceae, Pleosporaceae, Testudinaceae and Trematosphaeriaceae. Two new families are described: Aigialaceae and Morosphaeriaceae, and three new genera proposed: Halomassarina, Morosphaeria and Rimora. Few marine species are reported from the Dothideomycetidae (e.g. Mycosphaerellaceae, Capnodiales), a group poorly studied at the molecular level. New marine lineages include the Testudinaceae and Manglicola guatemalensis in the Jahnulales. Significantly, most marine Dothideomycetes are intertidal tropical species with only a few from temperate regions on salt marsh plants (Spartina species and Juncus roemerianus), and rarely totally submerged (e.g. Halotthia posidoniae and Pontoporeia biturbinata on the seagrasses Posidonia oceanica and Cymodocea nodosum). Specific attention is given to the adaptation of the Dothideomycetes to the marine milieu, new lineages of marine fungi and their host specificity

    The Impacts of Hydraulic Fracturing: Hands-On Activities for Undergraduate Students

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    According to the US Energy Information Administration, over 50% of the oil and natural gas produced in the US came from hydraulically fractured wells in 2015. While the economic and geopolitical benefits of this new industry are numerous, hydraulic fracturing (fracking) is still controversial because of its negative impacts on the environment such as ground and surface water contamination, air pollution, and increases in seismic activity near deep injection wells. Yet, it is only briefly mentioned in mainstream Geography textbooks and rarely taught in introductory Geography courses at Texas A&M. To address the current educational gap on fracking, I developed and implemented educational materials and associated activities that utilize several geographic learning methods. Specifically, I (1) prepared an introductory fracking lecture for GEOG 203 students, (2) prepared a debate scenario where students present alternative viewpoints about the impacts of fracking on local communities in the United States, (3) developed a data-driven exercise using Oklahoma earthquake data where students learn to analyze, graph, and interpret scientific datasets, and (4) assessed the success of some of my learning module via before and after quizzes. In 2016 and 2017, this fracking module was successfully implemented in GEOG 203, one of the top two core curriculum courses at Texas A&M related to environmental literacy. With this successful trial, I plan to disseminate the fracking module with an open-access publisher, making our documents freely available to all. Likewise, the hands-on exercises will be made freely available through the NAGT website

    Molecular systematics of the marine Dothideomycetes

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    Phylogenetic analyses of four nuclear genes, namely the large and small subunits of the nuclear ribosomal RNA, transcription elongation factor 1-alpha and the second largest RNA polymerase II subunit, established that the ecological group of marine bitunicate ascomycetes has representatives in the orders Capnodiales, Hysteriales, Jahnulales, Mytilinidiales, Patellariales and Pleosporales. Most of the fungi sequenced were intertidal mangrove taxa and belong to members of 12 families in the Pleosporales: Aigialaceae, Didymellaceae, Leptosphaeriaceae, Lenthitheciaceae, Lophiostomataceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae, Phaeosphaeriaceae, Pleosporaceae, Testudinaceae and Trematosphaeriaceae. Two new families are described: Aigialaceae and Morosphaeriaceae, and three new genera proposed: Halomassarina, Morosphaeria and Rimora. Few marine species are reported from the Dothideomycetidae (e.g. Mycosphaerellaceae, Capnodiales), a group poorly studied at the molecular level. New marine lineages include the Testudinaceae and Manglicola guatemalensis in the Jahnulales. Significantly, most marine Dothideomycetes are intertidal tropical species with only a few from temperate regions on salt marsh plants (Spartina species and Juncus roemerianus), and rarely totally submerged (e.g. Halotthia posidoniae and Pontoporeia biturbinata on the seagrasses Posidonia oceanica and Cymodocea nodosum). Specific attention is given to the adaptation of the Dothideomycetes to the marine milieu, new lineages of marine fungi and their host specificity

    Evidence for a Soft Nuclear Equation-of-State from Kaon Production in Heavy Ion Collisions

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    The production of pions and kaons has been measured in Au+Au collisions at beam energies from 0.6 to 1.5 AGeV with the Kaon Spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.Comment: 14 pages, 2 figures, accepted for publication in Phys. Rev. Let

    Production of Charged Pions, Kaons and Antikaons in Relativistic C+C and C+Au Collisions

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    Production cross sections of charged pions, kaons and antikaons have been measured in C+C and C+Au collisions at beam energies of 1.0 and 1.8 AGeV for different polar emission angles. The kaon and antikaon energy spectra can be described by Boltzmann distributions whereas the pion spectra exhibit an additional enhancement at low energies. The pion multiplicity per participating nucleon M(pi+)/A_part is a factor of about 3 smaller in C+Au than in C+C collisions at 1.0 AGeV whereas it differs only little for the C and the Au target at a beam energy of 1.8 AGeV. The K+ multiplicities per participating nucleon M(K+)/A_part are independent of the target size at 1 AGeV and at 1.8 AGeV. The K- multiplicity per participating nucleon M(K-)/A_part is reduced by a factor of about 2 in C+Au as compared to C+C collisions at 1.8 AGeV. This effect might be caused by the absorption of antikaons in the heavy target nucleus. Transport model calculations underestimate the K-/K+ ratio for C+C collisions at 1.8 AGeV by a factor of about 4 if in-medium modifications of K mesons are neglected.Comment: 19 pages, 14 figures, accepted for publication in Eur. Phys. J.

    Pleosporales

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    One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae

    Evidence for Different Freeze-Out Radii of High- and Low-Energy Pions Emitted in Au+Au Collisions at 1 GeV/nucleon

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    Double differential production cross sections of negative and positive pions and the number of participating protons have been measured in central Au+Au collisions at 1 GeV per nucleon incident energy. At low pion energies the pi^- yield is strongly enhanced over the pi^+ yield. The energy dependence of the pi^-/pi^+ ratio is assigned to the Coulomb interaction of the charged pions with the protons in the reaction zone. The deduced Coulomb potential increases with increasing pion c.m. energy. This behavior indicates different freeze-out radii for different pion energies in the c.m.~frame.Comment: IKDA is the Institute for Nuclear Physics in Darmstadt/German
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