2,025 research outputs found

    A phenomenological analysis of antiproton interactions at low energies

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    We present an optical potential analysis of the antiproton-proton interactions at low energies. Our optical potential is purely phenomenological, and has been parametrized on data recently obtained by the Obelix Collaboration at momenta below 180 MeV/c. It reasonably fits annihilation and elastic data below 600 MeV/c, and allows us for an evaluation of the elastic cross section and rho-parameter down to zero kinetic energy. Moreover we show that the mechanism that depresses antiproton-nucleus annihilation cross sections at low energies is present in antiproton-proton interactions too.Comment: 10 pages, 4 figure

    Self-energy of Lambda in finite nuclei

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    The self--energy of the strange baryon Λ\Lambda in 17^{17}O is calculated using a microscopic many--body approach which accounts for correlations beyond the mean--field or Hartree--Fock approximation. The non-locality and energy-dependence of the Λ\Lambda self--energy is discussed and the effects on the bound and scattering states are investigated. For the nucleon--hyperon interaction, we use the potential models of the J\"{u}lich and Nijmegen groups.Comment: 17 pages, Revtex Latex style, 7 figs include

    FBWatch: Extracting, Analyzing and Visualizing Public Facebook Profiles

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    An ever-increasing volume of social media data facilitates studies into behavior patterns, consumption habits, and B2B exchanges, so called Big Data. Whilst many tools exist for platforms such as Twitter, there is a noticeable absence of tools for Facebook-based studies that are both scalable and accessible to social scientists. In this paper, we present FBWatch, an open source web application providing the core functionality to fetch public Facebook profiles en masse in their entirety and analyse relationships between profiles both online and offline. We argue that FBWatch is a robust interface for social researchers and business analysts to identify analyze and visualize relationships, discourse and interactions between public Facebook entities and their audiences

    CLINICAL EVALUATION OF A SPECIFIC BENZODIAZEPINE ANTAGONIST (RO 15-1788): Studies in Elderly Patients after Regional Anaesthesia under Benzodiazepine Sedation

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    The efficacy, usefulness and side effects of RO 15-1788 (RO), a specific benzodiazepine (BZD) antagonist, have been evaluated. Sixty-two patients (ASA l-lll, mean age 72±9 yr) scheduled for urological surgery under regional anaesthesia and BZD sedation received placebo or RO in a randomized, double-blind fashion at the end of the procedure, folio wing sedation with midazolam. When compared with placebo, RO improved alertness and collaboration for 15 min, and suppressed anterograde amnesia for 60 min. No major side effect was noted, although five patients became anxious after administration of RO. Two cases of a paradoxical reaction to midazolam were treated successfully by R

    Rheology Dependent on the Distance to the Propagating Thrust Tip—(Ultra‐)Mylonites and Pseudotachylytes of the Silvretta Basal Thrust

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    To evaluate how the presence of pseudotachylytes affects the strength of crustal rocks, deformed pseudotachylytes and their relationship with pristine pseudotachylytes at the base of the Silvretta nappe are analyzed. Pseudotachylytes formed associated with high-stress crystal plasticity (σd > 400 MPa), as indicated by twinned amphiboles in gneisses. Mylonitic quartz clasts enclosed within deformed pseudotachylytes and mylonitic vein-quartz, hosting folded pseudotachylyte injection veins, reflect creep at lower stresses (ca. 100 MPa) after seismic rupturing. Deformed pseudotachylytes can be crosscut by pristine pseudotachylytes, indicating a second, independent stage of coseismic rupturing after creep. The evidence of dynamic dislocation creep of quartz and the presence of stilpnomelane and epidote associated with all fault rocks indicate similar ambient greenschist facies conditions during all deformation stages. Whereas the intermediate stage of creep is interpreted to represent deformation at large distance to the propagating thrust tip, the pristine pseudotachylytes represent the last stage of rupturing eventually leading to nappe decoupling from its basement. Gneiss clasts in an ultramylonitic matrix (i.e., deformed pseudotachylyte) reveal that pseudotachylytes have a lower strength during creep in relation to the hosting gneisses. In contrast, during coseismic high-stress crystal plasticity, the coarse gneisses accumulate a higher amount of strain. This strength-relationship explains that only those rocks rupture, which have not been previously deformed before. The study demonstrates the importance of different strengths of crustal rocks at specific stress- and strain-rate conditions in dependence on the distance to the propagating fault tip

    Pearl-chain waveguides machined with a femtosecond high-energy oscillator

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    A new regime of waveguides consisting of aligned spheres of strongly changed refractive - index in fused silica are explored and their guiding properties are measured

    Molecular evolutionary trends and biosynthesis pathways in the Oribatida revealed by the genome of Archegozetes longisetosus

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    Background Oribatid mites are a specious order of microarthropods within the subphylum Chelicerata, compromising about 11,000 described species. They are ubiquitously distributed across different microhabitats in all terrestrial ecosystems around the world and were among the first animals colonizing terrestrial habitats as decomposers and scavengers. Noted for their biosynthesis capacities and biochemical diversity, the majority of oribatid mites possess a pair of exocrine opisthonotal oil-glands used for chemical defense and communication. Genomic resources are lacking for oribatids despite their species richness and ecological importance. Results We used a comparative genomic approach to investigate the developmental, sensory and glandular biosynthetic gene repertoire of the clonal, all-female oribatid mite species Archegozetes longisetosus Aoki, a model species used by numerous laboratories for the past 30 years. Here, we present a 190-Mb genome assembly constructed from Nanopore MinION and Illumina sequencing platforms with 23,825 predicted protein-coding genes. Genomic and transcriptional analyses revealed patterns of reduced body segmentation and loss of segmental identity gene abd-A within Acariformes, and unexpected expression of key eye development genes in these eyeless mites across developmental stages. Consistent with the soil dwelling lifestyle, investigation of the sensory genes revealed a species-specific expansion of gustatory receptors, the largest chemoreceptor family in the genome used in olfaction, and evidence of horizontally transferred enzymes used in cell wall degradation of plant and fungal matter, both components of the Archegozetes longisetosus diet. Using biochemical and genomic data, we were able to delineate the backbone biosynthesis of monoterpenes, an important class of compounds found in the major exocrine gland system of Oribatida – the oil glands. Conclusions With the Archegozetes longisetosus genome, we now have the first high-quality, annotated genome of an oribatid mite genome. Given the mite’s strength as an experimental model, the new sequence resources provided here will serve as the foundation for molecular research in Oribatida and will enable a broader understanding of chelicerate evolution
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