1,622 research outputs found

    Performances of keystone geometry micro-strip gas chambers

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    Abstract The performances of micro-strip gas chamber detectors with CF 4 counting gas have been tested with a 241 Am α source. The behaviour of the gain as a function of gas pressure, the dependence of the energy resolution on gas pressure and anode voltage, and the gain variation along the strip length due to the keystone geometry of the micro-strip pads are reported. An empirical response function to describe such a position dependence of the gain is proposed

    A Model Checker for Operator Precedence Languages

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    The problem of extending model checking from finite state machines to procedural programs has fostered much research toward the definition of temporal logics for reasoning on context-free structures. The most notable of such results are temporal logics on Nested Words, such as CaRet and NWTL. Recently, Precedence Oriented Temporal Logic (POTL) has been introduced to specify and prove properties of programs coded trough an Operator Precedence Language (OPL). POTL is complete w.r.t. the FO restriction of the MSO logic previously defined as a logic fully equivalent to OPL. POTL increases NWTL's expressive power in a perfectly parallel way as OPLs are more powerful that nested words.In this article, we produce a model checker, named POMC, for OPL programs to prove properties expressed in POTL. To the best of our knowledge, POMC is the first implemented and openly available model checker for proving tree-structured properties of recursive procedural programs. We also report on the experimental evaluation we performed on POMC on a nontrivial benchmark

    Field Induced Staggered Magnetization and Magnetic Ordering in Cu2(C5H12N2)2Cl4Cu_2 (C_5 H_{12} N_2)_2 Cl_4

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    We present a 2^2D NMR investigation of the gapped spin-1/2 compound Cu2(C5H12N2)2Cl4Cu_2 (C_5 H_{12} N_2)_2 Cl_4. Our measurements reveal the presence of a magnetic field induced transverse staggered magnetization (TSM) which persists well below and above the field-induced 3D long-range magnetically ordered (FIMO) phase. The symmetry of this TSM is different from that of the TSM induced by the order parameter of the FIMO phase. Its origin, field dependence and symmetry can be explained by an intra-dimer Dzyaloshinskii-Moriya interaction, as shown by DMRG calculations on a spin-1/2 ladder. This leads us to predict that the transition into the FIMO phase is not in the BEC universality class.Comment: 4 page

    Experimental and theoretical cross sections for positron scattering from the pentane isomers

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    10 págs.; 8 figs.; 3 tabs.Isomerism is ubiquitous in chemistry, physics, and biology. In atomic and molecular physics, in particular, isomer effects are well known in electron-impact phenomena; however, very little is known for positron collisions. Here we report on a set of experimental and theoretical cross sections for low-energy positron scattering from the three structural isomers of pentane: normal-pentane, isopentane, and neopentane. Total cross sections for positron scattering from normal-pentane and isopentane were measured at the University of Trento at incident energies between 0.1 and 50 eV. Calculations of the total cross sections, integral cross sections for elastic scattering, positronium formation, and electronic excitations plus direct ionization, as well as elastic differential cross sections were computed for all three isomers between 1 and 1000 eV using the independent atom model with screening corrected additivity rule. No definitive evidence of a significant isomer effect in positron scattering from the pentane isomers appears to be present. ©2016 AIP Publishing LLCG.G. and F.B. would like to acknowledge the Spanish Ministerio de Economía y Productividad (Project No. FIS2012-31230) and the European Science Foundation (COST Action Grants Nos. MP1002–Nano-IBCT and MC1301-CELINA) for financial support. Finally, L.C. thanks the Japan Society for the Promotion of Science for his fellowship.Peer Reviewe

    The Orthopaedic forum 2011 Austrian-Swiss-German traveling fellowship tour summary

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    From January 31st to March 11th 2011 four traveling fellows representing the German speaking associated orthopaedic societies visited different academic orthopaedic centers in the U.K., Canada and the USA

    Universal hydrophilic coating of thermoplastic polymers currently used in microfluidics

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    A number of materials used to fabricate disposable microfluidic devices are hydrophobic in nature with water contact angles on their surface ranging from 80 to over 100. This characteristic makes them unsuitable for a number of microfluidic applications. Both the wettability and analyte adsorption parameters are highly dependent on the surface hydrophobicity. In this article, we propose a general method to coat the surface of five materials: polydimethylsiloxane (PDMS), cyclic olefin copolymer (COC), polyethylene terephthalate (PET), polycarbonate (PC), and polytetrafluoroethylene (PTFE). This fast and robust process, which is easily implementable in any laboratory including microfabrication clean room facilities, was devised by combining gas-phase and wet chemical modification processes. Two different coatings that improve the surface hydrophilicity were prepared via the "dip and rinse" approach by immersing the plasma oxidized materials into an aqueous solution of two different poly(dimethylacrylamide) copolymers incorporating a silane moiety and functionalized with either N-acryloyloxysuccinimide (NAS) (poly(DMA-NAS-MAPS) or glycidyl methacrylate (GMA) (poly(DMA-GMA-MAPS). The coating formation was confirmed by contact angle (CA) analysis comparing the variation of CAs of uncoated and coated surfaces subjected to different aging treatments. The antifouling character of the polymer was demonstrated by fluorescence and interferometric detection of proteins adsorbed on the surafce. This method is of great interest in microfluidics due to its broad applicability to a number of materials with varying chemical compositions

    Temporal lobe epilepsy and aura with happiness and pleasure: report of two cases and literature revision

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    The authors present two cases of temporal lobe epilepsy with happiness and pleasure during the seizure. Discussing the rarity of these clinical findings, the concept of epileptic aura is historically reviewed with special attention to Dostoievski's epilepsy and its descriptions by the medical literature.São apresentados 2 casos de epilepsia do lobo temporal nos quais os pacientes apresentam sensações de alegria e prazer durante a crise. Os autores analisam a evolução do conceito de aura epilética e discutem a controvertida questão da epilepsia em Dostoiévski, fazendo revisão da literatura sobre a existência do prazer e do êxtase como manifestação da doença.Escola Paulista de MedicinaUniversidade Católica de Santos Departamento de PsicologiaUNIFESP, EPMSciEL

    Variabilidade genética molecular entre acessos de Stylosanthes capitata e Stylosanthes macrocephala, resistentes e suscetíveis à antracnose.

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    Stylosanthes capitata e S. macrocephala são, atualmente, as leguminosas forrageiras mais importantes para incrementar a alimentação animal, como fonte de proteína para o gado, e para a recuperação de pastagens degradadas, por capacidade de fixação de nitrogênio no solo. Marcadores Random Amplified Polymorphic DNA (RAPD) foram utilizados com o objetivo de avaliar a variabilidade genética de 14 acessos, resistentes e suscetíveis à antracnose, dessas duas espécies. Um total de 154 bandas de DNA foi gerado usando-se 26 primers, e em S. capitata foram amplificadas 115 bandas e em S. macrocephala 105. Os índices de similaridade genética obtidos variaram de 0,741 a 0,913 em S. capitata e de 0,724 a 0,924 em S. macrocephala, revelando uma baixa variabilidade genética em cada espécie. Enquanto que, comparando-se os acessos das duas espécies, a média de similaridade foi 0,363, indicando uma alta variabilidade genética interespecífica. Um dendrograma foi construído conforme o método Unweighted Pair-group Method with Arithmetical Average (UPGMA) e dois grupos bem distintos foram formados, que corresponderam as duas espécies. Subgrupos puderam ser evidenciados em cada espécie, sem mostrar relação com a resistência ou suscetibilidade à antracnose. Resultado similar foi obtido com o método de Tocher, porém, nesse caso, em S. macrocephala os acessos resistentes ficaram agrupados separadamente dos suscetíveis. Esses resultados são relevantes na escolha de acessos resistentes à antracnose, visando ao desenvolvimento de novas cultivares a partir de misturas desses acessos ou seleção de genitores para cruzamentos.bitstream/item/29652/1/BP27.pd

    A first assessment of genetic variability in the longhorn beetle Rosalia alpina (Coleoptera: Cerambycidae) from the Italian Apennines

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    The Rosalia longicorn (Rosalia alpina) is a strictly protected saproxylic beetle, widely distributed in Central and Southern Europe and mainly associated with ancient beech forests. To improve knowledge about the conservation status of R. alpina in Italy, available molecular markers (microsatellites and mitochondrial cytochrome c oxidase I(COI)) were tested for the first time on Italian populations. The study was performed in four sampling sites distributed in two areas placed in Northern (“Foreste Casentinesi” National Park) and Central Apennines (“Abruzzo, Lazio and Molise” National Park) where populational data about Rosalia longicorn were collected in the framework of the European LIFE MIPP Project. The genetic relationship among Apennine and Central/South-eastern European populations was explored by a comparison with mitochondrial DNA (mtDNA) data from literature. Microsatellite markers were only partially informative when applied to R. alpina Italian individuals, although providing some preliminary indication on an extensive gene flow among populations from the Apennines and local ongoing processes of genetic erosion. Genetic data are consistent with previous ecological data suggesting that the maintenance of variability in this species could be related to both habitat continuity and preservation of large senescent or standing dead trees in forests. Finally, a peculiar origin of the Apennine populations of R. alpina from a putative “Glacial Refugium” in Italy was inferred through COI data. The high genetic distance scored among the analysed populations and those from Central and South-eastern Europe indicates that the R. alpina deme from Apennine Mountains might represent a relevant conservation unit in Europe. Further genetic analyses will allow assessing other possible conservation units of R. alpina and, thus, defining large-scale conservation strategies to protect this endangered longhorn beetle in Europe
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