8,760 research outputs found

    Intermediate Range Structure in Ion-Conducting Tellurite Glasses

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    We present ac conductivity spectra of tellurite glasses at several temperatures. For the first time, we report oscillatory modulations at frequencies around MHz. This effect is more pronounced the lower the temperature, and washes out when approaching the glass transition temperature TgT_g. We show, by using a minimal model, how this modulation may be attributed to the fractal structure of the glass at intermediate mesoscopic length scales

    Increase in pertussis cases along with high prevalence of two emerging genotypes of Bordetella pertussis in Perú, 2012

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    As has occurred in many regions worldwide, in 2012 the incidence of pertussis increased in Perú. This epidemiologic situation has been associated with a waning vaccine-induced immunity and the adaptation of Bordetella pertussis to vaccine-induced immunity along with improved diagnostic methods. Methods: The study comprised a total of 840 pertussis-suspected cases reported in Perú during 2012. We summarize here the distribution of pertussis cases according to age and immunization status along with the immunization-coverage rate. Laboratory diagnosis was performed by culture test and real-time polymerase-chain reaction (PCR). B. pertussis bacteria recovered from infected patients were characterized by pulsed-field gel electrophoresis (PFGE), and the DNA sequencing of the pertussis-toxin (promoter and subunit A), pertactin, and fimbriae (fim2 and fim3) genes. Results: From the total pertussis-suspected cases, 191 (22.7 %) infections were confirmed by real-time PCR and 18 through cultivation of B. pertussis (2.1 %), while one infection of B. parapertussis (0.11 %) was also detected by culture. Pertussis was significantly higher in patients that had had 0-3 vaccine doses (pentavalent vaccine alone) than in those who had had 4-5 vaccine doses (pentavalent plus DwPT boosters) at 94.3 vs. 5.7 %, respectively (p < 0.00001). The relative risk (RR) for patients with 4-5 doses compared to those with fewer than 4 doses or no dose was 0.23 (95 % Confidence Interval: 0.11-0.44), while the vaccine effectiveness was 77 % and coverage 50.5 %. Genetic analysis of B. pertussis isolates from different Peruvian regions detected two clonal groups as identified by PFGE. Those two groups corresponded to the B. pertussis genotypes emerging worldwide ptxP3-ptxA1-prn2 or 9-fim3-1 and ptxP3-ptxA1-prn2 or 9-fim3-2. Conclusions: Two emerging B. pertussis genotypes similar to isolates involved in worldwide epidemics were detected in Perú. Low vaccine coverage (<50 %) and genetic divergence between the vaccine-producing strain and the local isolates could contribute to this pertussal epidemic.Fil: Bailon, H. Instituto Nacional de Salud; PerúFil: León-Janampa, N. Instituto Nacional de Salud; PerúFil: Padilla, C.. Instituto Nacional de Salud; PerúFil: Hozbor, Daniela Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; Argentin

    Anomalous diffusion with log-periodic modulation in a selected time interval

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    On certain self-similar substrates the time behavior of a random walk is modulated by logarithmic periodic oscillations on all time scales. We show that if disorder is introduced in a way that self-similarity holds only in average, the modulating oscillations are washed out but subdiffusion remains as in the perfect self-similar case. Also, if disorder distribution is appropriately chosen the oscillations are localized in a selected time interval. Both the overall random walk exponent and the period of the oscillations are analytically obtained and confirmed by Monte Carlo simulations.Comment: 4 pages, 5 figure

    Territorial management and development. Towards a sustainable territorial development policy in Latin America. Ángel Massiris Cabeza

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    El libro que propone el geógrafo colombiano Ángel Massiris, centra su atención en la gestión y el desarrollo territorial sostenible, las ideas contenidas en él nos permite reflexionar sobre varias cosas que en el trasegar de la planificación de territorio muchas veces quedan olvidadas.Fil: Padilla Rodríguez, Cristian H.. Universidad Nacional de Cuy

    Economic development and environmental sustainability

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    La discusión actual sobre la importancia de la variable ambiental en la gestión del desarrollo económico a nivel internacional y especialmente en América Latina es ardua y complicada. Desde los ámbitos políticos, académicos, inversionistas y las fuerzas vivas de la sociedad hoy tienen discursos encontrados en los cuales existen múltiples posturas que defienden la necesidad de que exista un equilibrio entre las actividades económicas sobre el territorio y el ambiente, pero también están los que patrocinan la &quot;dominancia absoluta&quot; sobre los recursos naturales como único medio para lograr un desarrollo económico y una calidad de vida aceptable para las distintas sociedades.Fil: Padilla Rodríguez, Cristian H.. Universidad Nacional de Colombi

    Nuevos enfoques en el ordenamiento del territorio : el caso de la provincia de Mendoza, Argentina

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    Fil: Padilla Rodríguez, Cristian H.. Universidad Nacional de Cuyo. Facultad de Filosofía y Letras. Instituto de Investigación y Formación para el Ordenamiento Territoria

    Entangled spinning particles in charged and rotating black holes

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    Spin precession for an EPR pair of spin-1/2 particles in equatorial orbits around a Kerr-Newman black hole is studied. Hovering observers are introduced to ensure fixed reference frames in order to perform the Wigner rotation. These observers also guarantee a reliable direction to compare spin states in rotating black holes. The velocity of the particle due frame-dragging is explicitly incorporated by addition of velocities with respect the hovering observers and the corresponding spin precession angle is computed. The spin-singlet state is observed to be mixed with the spin-triplet by dynamical and gravity effects, thus it is found that a perfect anti-correlation of entangled states for these observers is deteriorated. Finally, an analysis concerning the different limit cases of parameters of spin precession including the frame-dragging effects is carried out.Comment: 25+1 pages, 7 eps figures. Major changes were made through all the manuscript. Clarifications regarding modifications were introduced through the draft. Figures were changed and reduced in number. arXiv admin note: text overlap with arXiv:quant-ph/030711

    Anisotropic anomalous diffusion modulated by log-periodic oscillations

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    We introduce finite ramified self-affine substrates in two dimensions with a set of appropriate hopping rates between nearest-neighbor sites, where the diffusion of a single random walk presents an anomalous {\it anisotropic} behavior modulated by log-periodic oscillations. The anisotropy is revealed by two different random walk exponents, νx\nu_x and νy\nu_y, in the {\it x} and {\it y} direction, respectively. The values of these exponents, as well as the period of the oscillation, are analytically obtained and confirmed by Monte Carlo simulations.Comment: 7 pages, 7 figure
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