3,819 research outputs found

    Ultrafast vectorial and scalar dynamics of ionic clusters: Azobenzene solvated by oxygen

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    The ultrafast dynamics of clusters of trans-azobenzene anion (A–) solvated by oxygen molecules was investigated using femtosecond time-resolved photoelectron spectroscopy. The time scale for stripping off all oxygen molecules from A– was determined by monitoring in real time the transient of the A– rise, following an 800 nm excitation of A– (O2)n, where n=1–4. A careful analysis of the time-dependent photoelectron spectra strongly suggests that for n>1 a quasi-O4 core is formed and that the dissociation occurs by a bond cleavage between A– and conglomerated (O2)n rather than a stepwise evaporation of O2. With time and energy resolutions, we were able to capture the photoelectron signatures of transient species which instantaneously rise (2- for A–O2 and A·O4-·(O2)n–2 for A–(O2)n, where n=2–4. Subsequent to an ultrafast electron recombination, A– rises with two distinct time scales: a subpicosecond component reflecting a direct bond rupture of the A–-(O2)n nuclear coordinate and a slower component (1.6–36 ps, increasing with n) attributed to an indirect channel exhibiting a quasistatistical behavior. The photodetachment transients exhibit a change in the transition dipole direction as a function of time delay. Rotational dephasing occurs on a time scale of 2–3 ps, with a change in the sign of the transient anisotropy between A–O2 and the larger clusters. This behavior is a key indicator of an evolving cluster structure and is successfully modeled by calculations based on the structures and inertial motion of the parent clusters

    Learning Agility: The Nexus Between Learning Organization, Transformative Learning, and Adaptive Performance

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    The purpose of this study is to establish a model of learning agility that is connected with transformative learning and the double-loop learning of organizational learning. Also, this study aims to identify the mediating role of learning agility on the relationship between learning organization, transformative learning, and adaptive performance

    Six-month mortality rates are lower in patients with an acute coronary syndrome treated with the combination of clopidogrel and a statin than in patients treated with either therapy alone: An analysis from the global registry of acute coronary events

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    La remunta la podem data de l'any 1928, aproximadament.Primer pla d'un edifici d'habitages, inicialment de planta baixa i pis, en quÚ es remunten tres plantes en la part de la parcel·la que forma xamfrà a tres carrers. La remunta forma un volum molt potent que revalora estÚticament l'edifici

    Index case finding facilitates identification and linkage to care of children and young persons living with HIV/AIDS in Malawi

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    OBJECTIVES: Evaluation of a novel index case finding and linkage-to-care programme to identify and link HIV-infected children (1-15 years) and young persons (>15-24 years) to care. METHODS: HIV-infected patients enrolled in HIV services were screened and those who reported untested household members (index cases) were offered home- or facility-based HIV testing and counselling (HTC) of their household by a community health worker (CHW). HIV-infected household members identified were enrolled in a follow-up programme offering home and facility-based follow-up by CHWs. RESULTS: Of the 1567 patients enrolled in HIV services, 1030 (65.7%) were screened and 461 (44.8%) identified as index cases; 93.5% consented to HIV testing of their households and of those, 279 (64.7%) reported an untested child or young person. CHWs tested 711 children and young persons, newly diagnosed 28 HIV-infected persons (yield 4.0%; 95% CI: 2.7-5.6), and identified an additional two HIV-infected persons not enrolled in care. Of the 30 HIV-infected persons identified, 23 (76.6%) were linked to HIV services; 18 of the 20 eligible for ART (90.0%) were initiated. Median time (IQR) from identification to enrolment into HIV services was 4 days (1-8) and from identification to ART start was 6 days (1-8). CONCLUSIONS: Almost half of HIV-infected patients enrolled in treatment services had untested household members, many of whom were children and young persons. Index case finding, coupled with home-based testing and tracked follow-up, is acceptable, feasible and facilitates the identification and timely linkage to care of HIV-infected children and young persons

    Susceptibility of hamsters to clostridium difficile isolates of differing toxinotype

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    Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD), which caused ~21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative), M68 (toxinotype VIII) and BI-7 (toxinotype III). The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c.) with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT) are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial and toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression

    Equilibrium shapes and energies of coherent strained InP islands

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    The equilibrium shapes and energies of coherent strained InP islands grown on GaP have been investigated with a hybrid approach that has been previously applied to InAs islands on GaAs. This combines calculations of the surface energies by density functional theory and the bulk deformation energies by continuum elasticity theory. The calculated equilibrium shapes for different chemical environments exhibit the {101}, {111}, {\=1\=1\=1} facets and a (001) top surface. They compare quite well with recent atomic-force microscopy data. Thus in the InP/GaInP-system a considerable equilibration of the individual islands with respect to their shapes can be achieved. We discuss the implications of our results for the Ostwald ripening of the coherent InP islands. In addition we compare strain fields in uncapped and capped islands.Comment: 10 pages including 6 figures. Submitted to Phys. Rev. B. Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm
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