972 research outputs found

    Climatic challenges of the city of Iquitos, Perú

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    El cambio climático ya está presente en las ciudades, afectando de manera diferente a cada una de estas. Iquitos la ciudad más importante de Amazonía peruana enfrenta lluvias cada vez más frecuentes e intensas lo que ocasiona que el agua de los ríos inunde la ciudad deteriorando la calidad de vida de sus habitantes, y se pierda infraestructura por miles de dólares. Además, Iquitos está rodeada de la mayor extensión de bosques del Perú. Sin embargo, la ciudad no ha logrado tener una adecuada relación ni con sus ríos ni con sus bosques lo cual dificulta la resiliencia de la ciudad. El artículo analiza los problemas y plantea los retos necesarios para enfrentar el cambio climático. Retos que van desde el nivel central de gobierno en relación con las competencias de Ordenamiento Territorial hasta los gobiernos locales y de los propios vecinos de la ciudad de Iquitos.Fil: Mayo D’Arrigo, Maritza. Illariy Consultoría, Desarrollo Urbano y Territoria

    Efecto del extracto acuoso de Origanum vulgare L. (Lamiaceae) en embrio- nes preimplantacionales de ratón

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    The use of medicinal plants for the treatment of illnesses is widely known. However, there are not many scientific reports about the properties of these plants and their side effects. In this study, the effect of the aqueous extract of Origanum vulgare on the preimplantational mouse embryo development was investigated. The oregano aqueous extract was given ad libitum to four separated groups (n= 10) of pregnant mice: O, 9, 18 y 36 mg/mL respectively. When the embryos were evaluated, a slight delay in the embryo development was observed, but only with the highest dose. With respect to embryo quality, an increase of degenerated embryos was observed but this was not significant. These results showed that the aqueous extract of O. vulgare does not have a toxic effect on preimplantational mouse embryo, and it only produces a slight delay in embryo development.El uso de las plantas medicinales para el tratamiento de las enfermedades es ampliamente conocido. Sin em- bargo, no hay muchos informes científicos sobre las propiedades de dichas plantas y sus efectos secundarios. En este estudio, se ha investigado el efecto del extracto acuoso de Origanum vulgare en el desarrollo preim- plantacional de embriones de ratón. El extracto acuoso fue administrado (0, 9, 18 y 36 mg/mL): vía oral; ad libitum, respectivamente a cuatro grupos de ratonas preñadas (n= 10). Cuando los embriones fueron evaluados sólamente con la dosis más alta se observó un ligero retraso en el desarrollo del embrión. Con respecto a la calidad del embrión, se evidencio un aumento de embriones degenerados, pero esto no fue significativo. Estos resultados mostraron que el extracto acuoso de O. vulgare no tiene un efecto tóxico en embriones de ratón preimplantacional, y sólo produce un ligero retraso en el desarrollo del embrión

    Bremsstrahlung Spectrum in alpha Decay

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    Using our previous approach to electromagnetic emission during tunneling, an explicit, essentially classical, formula describing the bremsstrahlung spectrum in alpha decay is derived. The role of tunneling motion in photon emission is discussed. The shape of the spectrum is a universal function of the ratio Eg/Eo , where Eg is the photon energy and Eo is a characteristic energy depending only on the nuclear charge and the energy of the alpha particle.Comment: 8 pages, 3 figure

    Comparison of Postoperative Fever and Effectiveness of Percutaneous Nephrolithotomy (PCNL) Versus Retrograde Intrarenal Surgery (RIRS) for the Treatment of Renal Stones

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    The aim of this study is to compare the effectiveness and the relative risk of postoperative fever between percutaneous nephrolithotomy and retrograde intrarenal surgery for the treatment of renal stones. At the Cannizzaro Hospital in Catania, a total 168 patients with one or more renal stones underwent one of more interventions, resulting in 177 independent records; 62 records related to PCNL treatment and 115 records involved RIRS treatment. To assess the relationship between patient and stone characteristics on the one hand and stone-free rate and the incidence rate of postoperative fever on the other, a generalized additive logistic models was used. We found that stone burden, defined in terms of stone diameter, the number of stones and stone density, is a significant predictor for the success of the intervention. Furthermore, PCNL treatment was significantly less successful for stone in the middle calyx, whereas RIRS obtained significantly lower success rate for stone in the lower calyx that had a sharp infundibular angle. Importantly, for renal stones with a diameter up to 2 cm, RIRS has a very similar success rate compared to PCNL. Stones with a diameter larger than 2 cm are best treated by PCNL. Across the two treatments, older patients and men have lower incidence rate of postoperative fevers. The fact that RIRS has much lower postoperative fever rates for male and younger patients compared to PCNL, means that RIRS could be the treatment of choice for small and midsized stones for such patients

    Las Memorias más allá de las cuatro paredes. Reflexiones en torno al Museo de la Memoria de la Ciudad de Rosario

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    En este trabajo me centraré en analizar procesos de resistencias sociales en torno al Museo de la Memoria de la ciudad de Rosario, situado en un edificio que condensa un gran valor histórico, político y social ya que allí funcionó, durante la última dictadura cívico-militar, el Comando del II Cuerpo de Ejército, espacio en donde se ideó el plan sistemático de represión a las provincias del litoral del país, se realizaron los consejos de guerra a presxs y detenidxs políticxs, y se constituyó en lugar de reclamo y reunión de familiares de presxs, detenidxs y desaparecidxs. El Museo se inaugura en su actual sede recién en el año 2010, fruto de intensas disputas por parte de los activismos de derechos humanos locales. En este sentido, rescataré innovadoras intervenciones estético- políticas enmarcadas en dicho repertorio de protestas sociales de comienzos de este siglo. Por otrolado, hondaré sobre la muestra permanente del Museo y los ejes temáticos que aborda.Específicamente observaré las obras artísticas y el guion museológico propuesto con una mirada y escucha atenta en rastrear los relatos y las memorias que allí se recogen y se eligen “exponer” sobre el periodo dictatorial y los modos en que se ven permeadas, atravesadas y dialogan con debates y resistencias actuales

    Towards fabrication of ordered gallium nanostructures by laser manipulation of neutral atoms: study of self-assembling phenomena

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    Surface diffusion has an impact on the lateral resolution of nanostructures in bottom-up atom nanofabrication. In this paper we study the effects of the gallium atoms self-assembled on silicon surfaces (100) patterned with trenches at different slopes. These particular substrate morphologies have been made to enable an effective deposition rate variation along the surface. In this way we experimentally mimic the effect of the atomic flux modulation created by standing wave during an atom nanofabrication experiment. Even if we observe self organization of gallium atoms on the surface, we conclude that the nano-islands are not affected by surface diffusion processes and the effective variation of the deposition rate per unit area is the dominant factor affecting the growth differences along the surface. This result demonstrates that the gallium atoms self-organization should not prevent the observation of a periodic nano-patterning created by atom nano-fabrication techniques.Comment: 7 pages, 5 figures, EMRS conference procee

    Obsessive–compulsive traits in children and adolescents with Asperger syndrome

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    The objective of this study is to examine the occurrence and characteristic features of obsessive–compulsive behaviours in children and adolescents with Asperger syndrome (AS), with respect to a matched obsessive compulsive disorder group (OCD) and a typically developing control group (CG). For this purpose, 60 subjects (20 OCD; 18 AS; 22 CG), aged 8–15 years, matched for age, gender and IQ were compared. AS and OCD patients were diagnosed according to the DSM-IV-TR criteria. The Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule were used to assist in the AS diagnosis; the WISC-R was administered to assess IQ. Obsessive and compulsive symptoms were evaluated by using the Children’s Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). None of the AS children received a formal diagnosis of OCD. The AS group presented significantly higher frequencies of Hoarding obsessions and Repeating, Ordering and Hoarding compulsions compared to CG. The OCD group, in turn, reported significantly higher frequencies of Contamination and Aggressive obsessions and Checking compulsions compared to both the AS group and CG. As expected, the OCD group displayed a higher severity of symptoms (Moderate level of severity) than did the AS group (Mild level of severity). Finally, in our sample, neither the OCD group nor the AS group demonstrated a completely full awareness of the intrusive, unreasonable and distressing nature of symptoms, and the level of insight did not differ between the OCD group and CG, although an absence of insight was observed in the AS group. Children with AS showed higher frequencies of obsessive and compulsive symptoms than did typically developing children, and these features seem to cluster around Hoarding behaviours. Additionally, different patterns of symptoms emerged between the OCD and AS groups. Finally, in our sample, the level of insight was poor in both the OCD and the AS children. Further research should be conducted to better understand the characteristics of repetitive thoughts and behaviours in autism spectrum disorders, and to clarify the underlying neurobiological basis of these symptoms

    Entanglement dynamics in superconducting qubits affected by local bistable impurities

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    We study the entanglement dynamics for two independent superconducting qubits, each affected by a bistable impurity generating random telegraph noise (RTN) at pure dephasing. The relevant parameter is the ratio g between the qubit–RTN coupling strength and the RTN switching rate, which captures the physics of the crossover between Markovian and non-Markovian features of the dynamics. For identical qubit–RTN subsystems, a threshold value gth of the crossover parameter separates exponential decay and the onset of revivals; different qualitative behaviors also show up by changing the initial conditions of the RTN. We also show that, for different qubit–RTN subsystems, when both qubits are very strongly coupled to the RTN, an increase of entanglement revival amplitude may occur during the dynamics

    Dynamical suppression of telegraph and 1/f noise due to quantum bistable fluctuator

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    We study dynamical decoupling of a qubit from non gaussian quantum noise due to discrete sources, as bistable fluctuators and 1/f noise. We obtain analytic and numerical results for generic operating point. For very large pulse frequency, where dynamic decoupling compensates decoherence, we found universal behavior. At intermediate frequencies noise can be compensated or enhanced, depending on the nature of the fluctuators and on the operating point. Our technique can be applied to a larger class of non-gaussian environments.Comment: Revtex 4, 5 pages, 3 figures. Title revised and some other minor changed. Final version as published in PR
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