1,275 research outputs found

    Nanosized patterns as reference structures for macroscopic transport properties and vortex phases in YBCO films

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    This paper studies the striking correlation between nanosized structural patterns in YBCO films and macroscopic transport current. A nanosized network of parallel Josephson junctions laced by insulating dislocations is almost mimicking the grain boundary structural network. It contributes to the macroscopic properties and accounts for the strong intergranular pinning across the film in the intermediate temperature range. The correlation between the two networks enables to find out an outstanding scaling law in the (Jc,B) plane and to determine meaningful parameters concerning the matching between the vortex lattice and the intergranular defect lattice. Two asymptotic behaviors of the pinning force below the flux flow regime are checked: the corresponding vortex phases are clearly individuated.Comment: 4 pages, 4 figure

    Tuberculosis treatment in a refugee and migrant population: 20 years of experience on the Thai-Burmese border.

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    Although tuberculosis (TB) is a curable disease, it remains a major global health problem and an important cause of morbidity and mortality among vulnerable populations, including refugees and migrants

    Precipitación y escurrimientos superficiales de ríos andinos

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    Se analizan las relaciones existentes entre la precipitación calda en diversas regiones de Chile con los escurrimientos superficiales de ríos andinos. Se muestra que la precipitación media regional ajusta mejor a los escurrimientos, y que la relación entre ambas variables es de tipo curvilínea. Posteriormente se Infiere la probable causa de esta respuesta y se comparan los diferentes comportamientos entre ellas.The relationship between the preclpltations observed in dlfferent sites in Chile and the river runoffs of the Andean rivers in Argentlne are anallzed. It is shown that the mean regional preclpitation flts well with the runoffs; it is also observed that the relationshlp between both variables is not linear. The problable cause is inferred and different behaviours are compared.Asociación Argentina de Geofísicos y Geodesta

    The velo-uvulo-pharyngeal lift or "roman blinds" technique for treatment of snoring: a preliminary report

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    Snoring is caused by vibrating anatomical structures in the upper aerodigestive tract. It can be treated surgically and non-surgically, although resective procedures are associated with high postoperative morbidity and failure rate. We describe a new non-resective surgical procedure called the velo-uvulo-pharyngeal lift in which the soft palate is lifted, shortened, advanced and stiffened by means of permanent threads anchored to fibro-osseous attachments at the level of the posterior nasal spine and both pterygoid hamuli. Four adult patients (median age 44.5 years; range 42-65) affected by snoring and mild obstructive sleep apnoea-hypopnoea syndrome (apneoa-hypopnoea index, AHI < 20) requiring septal surgery under general anesthesia also underwent velo-uvulo-pharyngeal lift. There were no significant intra- or post-operative complications, and all of the patients reported immediate snoring relief. The main complaints were slight pain and a sensation of local fullness, both of which spontaneously disappeared within two days. The subjective clinical improvement in snoring was confirmed during post-operative follow-up (median 15.5 months; range 6-25), as was the stable reshaping of the soft velo-uvulo-pharyngeal tissues and enlargement of the mesopharyngeal space. There was also a decrease in daytime sleepiness. Our preliminary results suggest that velo-uvulo-pharyngeal lift is a simple, cost-effective and minimally invasive means of widening the mesopharyngeal space in snoring patients with or without mild sleep apnoea-hypopnoea syndrome. The widening of the mesopharyngeal space prevents contact-induced wall vibrations and its inspiratory obstruction causing hypopnoea and apnoea. It can also be combined with other procedures if indicated

    Persistence in surface overflow of Andean rivers

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    The temporal structure of both deficit (negative) and excess (positive) periods in surface overflow of Andean rivers were analyzed by studying the runs. In Southern areas (in the province of Neuquén and the Southern part of the province of Mendoza), positive and negative groups of anomalies have been found to diminish geometrically over the years. In the Northern areas (in the province of San Juan and Northern part of the province of Mendoza) persistence occurs in negative runs only. This behavior is produced by the influence of the basins located in an arid zone, because of the heterogeneity in the structure of the precipitation in this region.En este trabajo se analiza el comportamiento de la persistencia en el escurrimiento superficial de los ríos andinos, usando el método de rachas de eventos con anomalías positivas o negativas. Se ha encontrado que las rachas positivas o negativas tienen en la zona más austral (provincia de Neuquén y sur de Mendoza) un decaimiento de tipo geométrico con los años; en cambio, hacia la zona más septentrional (provincia de San Juan y norte de Mendoza) aparece la persistencia solamente en las rachas negativas o de sequías. Este comportamiento no se encuentra en la estructura de la precipitación que cae en la cuenca, por lo tanto, se infiere que el mismo sería debido a la regulación que ejercen las cuencas del norte, inmersas en una región de clima árido.Material digitalizado en SEDICI gracias a la colaboración de la Facultad de Ciencias Astronómicas y Geofísicas (UNLP).Asociación Argentina de Geofísicos y Geodesta

    Contrasting main selection methods in genetic algorithms

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    In genetic algorithms selection mechanisms aim to favour reproduction of better individuals imposing a direction on the search process. It does not create new individuals; instead it selects comparatively good individuals from a population and typically does it according to their fitness. The idea is that interacting with other individuals (competition), those with higher fitness have a higher probability to be selected for mating. In that manner, because the fitness of an individual gives a measure of its "goodness", selection introduces the influence of the fitness function to the evolutionary process. Moreover, selection is the only operator of genetic algorithm where the fitness of an individual affects the evolution process. In such a process two important, strongly related, issues exist: selective pressure and population diversity. They are the sides of the same coin: exploitation of information gathered so far versus exploration of the searching space. Selection plays an important role here because strong selective pressure can lead to premature convergence and weak selective pressure can make the search ineffective [14]. Focussing on this equilibrium problem significant research has been done. In this work we introduce the main properties of selection, the usual selection mechanisms and finally show the effect of applying proportional, ranking and tournament selection to a set of well known multimodal testing functions on simple genetic algorithms. These are the most widely used selection mechanisms and each of them has their own features. A description of each method, experiment and statistical analyses of results under different parameter settings are reported.Sistemas InteligentesRed de Universidades con Carreras en Informática (RedUNCI

    Improving evolutionary algorithms performance by extending incest prevention

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    Provision of population diversity is one of the main goals to avoid premature convergence in Evolutionary Algorithms (EAs). In this way the risk of being trapped in local optima is minimised. Eshelman and Shaffer [4] attempted to maintain population diversity by using diverse strategies focusing on mating, recombination and replacement. One of their approaches, called incest prevention, avoided mating of pairs showing similarities based on the parent’s hamming distance. Conventional selection mechanisms does not consider if the members of the new population have common ancestors and consequently due to a finite fixed population size, a loss of genetic diversity can frequently arise. This paper shows an extended approach of incest prevention by maintaining information about ancestors within the chromosome and modifying the selection for reproduction in order to impede mating of individuals belonging to the same “family”, for a predefined number of generations. This novel approach was tested on a set of multimodal functions. Description of experiments and analyses of improved results are also shown.Sistemas InteligentesRed de Universidades con Carreras en Informática (RedUNCI

    Health-related quality of life and functional changes in DMD:A 12-month longitudinal cohort study

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    Family caregivers of people with amyotrophic lateral sclerosis (ALS) live stressful lives in which they spend most of their time caring for their loved ones and managing difficult situations, thereby reducing the time spent in taking care of themselves. This situation may last several years. Previous literature has widely highlighted that this situation reduces caregivers' quality of life and increases their psychological distress and risk of health problems, but there is a lack of studies that focus on psychological interventions for these situations. This qualitative study examined a pilot experience of two mutual support groups for family caregivers of people with ALS. The aim was to identify caregivers' needs, the prominent aspects of their experience, and to understand whether and how this intervention strategy might help them. Six partners (four men and two women) and six adult children (five women and one man) participated in the groups, which were conducted in northern Italy. After the support groups finished, participants underwent semi-structured interviews. The authors conducted a content analysis of the transcripts of the interviews and the 20 group sessions. The thematic areas identified were "caregiving," "being the son/daughter of a person with ALS," "being the partner of a person with ALS," "group experience" and "group evaluation." The caregiving experience was profoundly different depending on whether the caregiver was a son/daughter or a partner of a patient with ALS. Moreover, comparison with peers and mutual support helped participants to better cope with ALS and its consequences, to improve their care for their relatives and to overcome typical caregiver isolation. These results suggest the usefulness of involving communities in caregiver support in order to create new networks and activate personal and social resources for well-being

    A new apparatus for deep patterning of beam sensitive targets by means of high-energy ion beam

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    The paper reports on a high precision equipment designed to modify over 3-dimensions (3D) by means of high-energy gold ions the local properties of thin and thick films. A target-moving system aimed at creating patterns across the volume is driven by an x-y writing protocol that allows one to modify beam sensitive samples over micrometer-size regions of whatever shape. The apparatus has a mechanical resolution of 15 nm. The issue of the local fluence measurement has been particularly addressed. The setup has been checked by means of different geometries patterned on beam sensitive sheets as well as on superconducting materials. In the last case the 3D modification consists of amorphous nanostructures. The nanostructures create zones with different dissipative properties with respect to the virgin regions. The main analysis method consists of magneto-optical imaging that provides local information on the electrodynamics of the modified zones. Features typical of non-linear current flow hint at which pattern geometry is more functional to applications in the framework of nanostructures across superconducting films.Comment: 7 page
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