2,574 research outputs found

    Dynamic heterogeneity in the glass-like monoclinic phases of some halogen methane compounds

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    In this work we study the heterogeneity of the dynamics on the low-temperature monoclinic phases of the simple molecular glassy systems CBrnCl4−nCBrnCl4−n, n = 0, 1, 2. In these systems the disorder comes exclusively from reorientational jumps mainly around the C3 molecular axes. The different time scales are determined by means of the analysis of the spin-lattice relaxation time obtained through Nuclear Quadrupole Resonance (NQR) technique. Results are compared with those obtained from dielectric spectroscopy, from which two α- and β-relaxation times appear. NQR results enable us to ascribe with no doubt that the existence of two relaxations is due to dynamical heterogeneities which are the consequence of the different molecular surroundings of the molecules in the asymmetric unit cell of systems here studied.Fil: Zuriaga, Mariano Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Perez, S. C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Pardo, L. C.. Universidad Politecnica de Catalunya; EspañaFil: Tamarit, J. L.. Universidad Politecnica de Catalunya; Españ

    Effectiveness and costs of phototest in dementia and cognitive impairment screening

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    <p>Abstract</p> <p>Background</p> <p>To assess and compare the effectiveness and costs of Phototest, Mini Mental State Examination (MMSE), and Memory Impairment Screen (MIS) to screen for dementia (DEM) and cognitive impairment (CI).</p> <p>Methods</p> <p>A phase III study was conducted over one year in consecutive patients with suspicion of CI or DEM at four Primary Care (PC) centers. After undergoing all screening tests at the PC center, participants were extensively evaluated by researchers blinded to screening test results in a Cognitive-Behavioral Neurology Unit (CBNU). The gold standard diagnosis was established by consensus of expert neurologists. Effectiveness was assessed by the proportion of correct diagnoses (diagnostic accuracy [DA]) and by the kappa index of concordance between test results and gold standard diagnoses. Costs were based on public prices and hospital accounts.</p> <p>Results</p> <p>The study included 140 subjects (48 with DEM, 37 with CI without DEM, and 55 without CI). The MIS could not be applied to 23 illiterate subjects (16.4%). For DEM, the maximum effectiveness of the MMSE was obtained with different cutoff points as a function of educational level [k = 0.31 (95% Confidence interval [95%CI], 0.19-0.43), DA = 0.60 (95%CI, 0.52-0.68)], and that of the MIS with a cutoff of 3/4 [k = 0.63 (95%CI, 0.48-0.78), DA = 0.83 (95%CI, 0.80-0.92)]. Effectiveness of the Phototest [k = 0.71 (95%CI, 0.59-0.83), DA = 0.87 (95%CI, 0.80-0.92)] was similar to that of the MIS and higher than that of the MMSE. Costs were higher with MMSE (275.9 ± 193.3€ [mean ± sd euros]) than with Phototest (208.2 ± 196.8€) or MIS (201.3 ± 193.4€), whose costs did not significantly differ. For CI, the effectiveness did not significantly differ between MIS [k = 0.59 (95%CI, 0.45-0.74), DA = 0.79 (95%CI, 0.64-0.97)] and Phototest [k = 0.58 (95%CI, 0.45-0.74), DA = 0.78 (95%CI, 0.64-0.95)] and was lowest for the MMSE [k = 0.27 (95%CI, 0.09-0.45), DA = 0.69 (95%CI, 0.56-0.84)]. Costs were higher for MMSE (393.4 ± 121.8€) than for Phototest (287.0 ± 197.4€) or MIS (300.1 ± 165.6€), whose costs did not significantly differ.</p> <p>Conclusion</p> <p>MMSE is not an effective instrument in our setting. For both DEM and CI, the Phototest and MIS are more effective and less costly, with no difference between them. However, MIS could not be applied to the appreciable percentage of our population who were illiterate.</p

    CARACTERISTICAS DE CEPAS CHILENAS DE Pyrenochaeta lycopersici Y PERSPECTIVAS DE CONTROL BIOLOGICO

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    Raíz corchosa es una de las principales enfermedades que afecta al cultivo de tomate que se produce bajo invernadero frío en Chile. En esta investigación se entregan antecedentes referentes a las principalescaracterísticas reproductivas de su agente causal, Pyrenochaeta lycopersici, como: picnidios, conidióforos y conidios. Además, antecedentes sobre la estrategia de control biológico de esta enfermedad. En base a estudios preliminares, se determinó a Trichoderma harzianum, como el taxa más promisorio (según cultivos duales).Se caracterizaron cepas de ambas especies de acuerdo a crecimiento micelial a diferentes temperaturas, pH, y salinidad (NaCl). Finalmente, se efectuó un ensayo bajo condiciones controladas de invernadero, destacándose la cepa Th11 como la más promisoria en el biocontrol de este patógeno

    First tests of the applicability of gamma-ray imaging for background discrimination in time-of-flight neutron capture measurements

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    In this work we explore for the first time the applicability of using gamma-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr3 scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a Au-197 sample have been carried out at n_TOF, achieving an enhancement of a factor of two in the signal-to-background ratio when selecting only those events coming from the direction of the sample. (C) 2016 Elsevier B.V. All rights reserved.Postprint (author's final draft

    Studi Implementasi Pendidikan Karakter Pada Pembelajaran Matematika Pada Kelas Cerdas Istimewa Bakat Istimewa (Cibi) SMP Negeri 2 Surakarta

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    The objective of research was to describe the implementation of character education to mathematics learning, the constraints the teacher faced and the solution the teachers took to the constraints with the implementation of character education in mathematics learning in the gifted and talented class of SMP Negeri 2 Surakarta. This study was a descriptive qualitative research; the subject of researcher was one mathematics teacher and six students in the grade VII gifted and talented class. Techniques of validating data used were researcher persistence and time triangulation. Techniques of analyzing data used were (1) data reduction, (2) data display, and (3) conclusion drawing and verification. The results of research are as follows. 1) The process of character education implementation to learning was below. (a) The development of logical, critical, creative and innovative thinking character was conducted by means of assignment, directing the students to the correct answer and to make decision with debriefing. (b) The development of hard work character was conducted by means of group assignment. (c) The development of curiosity character was conducted by providing the example of material existing in real life. (d) The development of independency character was conducted by assigning the material reading to be discussed in the next meeting. (e) The development of self-confidence character was conducted by means of facilitating the students writing the result on the blackboard. 2) The constraints the teacher faced and the solutions the teacher took were as follows. (a) In the implementation of logical, critical, creative and innovative thinking character, the students monopolized actively the debriefing process so that the teacher should limit and provide other students the opportunity of asking question. (b) In the implementation of hard work character, not all students in the classroom had equal hard work ethos. The solutions taken were to play motivation video and to convince them about the ability they had, to display the students\u27 work, and to reward the students with the best performance. (c) In the implementation of curiosity character, the students who did not want to think too hard responded poorly to the stimulus given. In this case, the teacher could give reward in the form of mark (grade). (d) In the implementation of self-confidence character, the students with less self-confidence would select the easy assignment in presenting the group assignment, and they explained in very soft voice. The solutions taken were to give more mark to the students explaining group assignment, and to direct the students in the presentation. For teacher independency character, the teacher did not face a significant constraint

    Characterization of the n-TOF EAR-2 neutron beam

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    The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n-TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam prole and the shape of the neutron 'ux at EAR-2. The prompt γ-flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this γ-flash
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