3,048 research outputs found

    A Methodology for Classifying Search Operators as Intensification or Diversification Heuristics

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    Selection hyper-heuristics are generic search tools that dynamically choose, from a given pool, the most promising operator (low-level heuristic) to apply at each iteration of the search process. The performance of these methods depends on the quality of the heuristic pool. Two types of heuristics can be part of the pool: diversification heuristics, which help to escape from local optima, and intensification heuristics, which effectively exploit promising regions in the vicinity of good solutions. An effective search strategy needs a balance between these two strategies. However, it is not straightforward to categorize an operator as intensification or diversification heuristic on complex domains. Therefore, we propose an automated methodology to do this classification. This brings methodological rigor to the configuration of an iterated local search hyper-heuristic featuring diversification and intensification stages. The methodology considers the empirical ranking of the heuristics based on an estimation of their capacity to either diversify or intensify the search. We incorporate the proposed approach into a state-of-the-art hyper-heuristic solving two domains: course timetabling and vehicle routing. Our results indicate improved performance, including new best-known solutions for the course timetabling problem

    Microwave-assisted in situ laser dye incorporation into high sensitivity whispering gallery mode microresonators

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    Optical whispering gallery mode microresonators (WGM-μRs) are powerful sensitive components with many analytical applications. Here, spherical WGM-μRs have been synthesised in a single-step microwave (MW)-assisted heterophase polymerisation. The microresonators are based on poly(styrene) beads into which the organic lasing dye nile red was incorporated as gain medium in situ during the polymerisation. The particle diameter and diameter distribution of the synthesised particles were tuned in the range of around 200 nm up to 50 μm by adjusting the concentration between stabiliser poly-(N-vinyl pyrrolidone) (PVP) and monomer styrene, and the solvent composition in the dispersion process. Lower water content enabled the synthesis of spherical particles with large size polydispersity, from which WGM-μRs with a variety of diameters were selected. Microspheres with diameters ≳3.5 μm supported WGMs. The WGMs were excited through free space via the fluorescence of the laser dye. Pumping power levels <1 μW were sufficient to excite WGMs. WGM shifts of beads with diameter between ≈5 and 30 μm measured in air and water show a sensitivity up to 54 nm/RIU for the smallest particles. Dye doped WGM-μR in the low μm size range obtained by the MW-assisted polymerisation process with its versatility, low processing times and high yields opens new horizons for the applications of these systems as sensors

    Effectiveness of vaginal analgesic electrostimulation versus sacral electroacupuncture in chronic pelvic pain of myofascial origin

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    Background: Chronic pelvic pain (CPP) of myofascial origin is a condition that is difficult to control and with great repercussion on the quality of life for women who suffer from it. This study objective was to compare the effectiveness of two treatments for the management of this pathology; vaginal analgesic electrostimulation (VES) versus sacral electroacupuncture (EAS).Methods: Quasi-experimental comparative study of two treatments in patients with myofascial CPP. The sample was made up of women who presented this condition during the period 2016 to 2019. The main objective was to assess the effectiveness of the treatments in comparison in terms of the decrease in the VAS score, the secondary ones were: To know the effectiveness of the VES for pain chronic pelvic myofascial (MFPP), the effectiveness of EA for the same condition, complications of therapies, main urological dysfunctions and other chronic pelvic pain associated with myofascial CPP.Results: Thirteen thousand patient files were reviewed, of which 47 were diagnosed with myofascial CCP, with 38 patients eligible for our study. The VES was more effective than the EAS in decreasing the VAS in the twelfth session from 1.36 versus 2.62 p .001. Both therapies were effective for the management of myofascial DCP as they decreased the VAS score to more than 60% of the initial VAS. Vulvodynia (34%), mixed urinary incontinence (32%), and voiding symptoms (26%) were other pelvic floor dysfunctions that presented concomitantly to the MFPP.Conclusions: In patients with myofascial CPP, vaginal VES is better than AD for the treatment of this condition

    TV watching modifies obesity risk linked to the 27Glu polymorphism of the ADRB2 gene in girls

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    OBJECTIVE: A matched case-control study was conducted in a population of Spanish children and adolescents (5-18 years old), to assess the interaction between the Gln27Glu polymorphism of the ADRB2 and television (TV) watching on obesity risk. PATIENTS: Obese (n=165) and control subjects (n=165) matched by sex and age were recruited and classified according to Spanish reference data. Results. Using conditional logistic regression, we calculated the obesity risk linked to the polymorphism. A statistically significant association was found for 27Glu carrier allele girls (OR = 1.95; 95% CI = 1.02-3.70), but no association was apparent among boys. In the fully adjusted model, the odds ratio for obesity linked to the genotype Glu27Glu in the female population rose to 4.84 (95% CI = 1.37-17.10). Moreover, we found a significant negative interaction between hours of TV watching and the Gln27Glu polymorphism for obesity risk in girls. Surprisingly, among 27Glu carrier subjects, even girls with a low level of TV watching ( < 12.5 h/week) had a high obesity risk (OR = 4.60; 95% CI = 1.01-20.02), which was not very different to the odds ratio values for sedentary girls carrying the 27 Glu allele watching TV more than 12.5 h/week (OR = 6.05; 95% CI = 1.31-27.71). Conclusion. A higher risk of obesity was found for girls carrying the 27Glu allele of the ADRB2 gene even when they spent less than 12.5 h/week watchi

    Dietary total antioxidant capacity and obesity in children and adolescents

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    Dietary antioxidant intake has been suggested to protect against oxidative damage and related clinical complications. The aim of this study was to assess the potential relationships between the dietary total antioxidant capacity (TAC) and obesity-related features in children and adolescents. Anthropometric variables from 369 children and adolescents were measured (184 obese and 185 control). A validated food-frequency questionnaire was used to calculate the TAC and the daily nutrient and energy intake. Dietary TAC showed positive associations with fiber, folic acid, magnesium, and vitamins A, C and E. BMI, SDS-BMI and total body fat were inversely associated with dietary TAC only in obese subjects. These data suggest that dietary TAC may be a potential indicator of the risk to develop obesity-related features and could be considered as a useful method in assessing antioxidant intake

    Glioblastoma on a microfluidic chip: Generating pseudopalisades and enhancing aggressiveness through blood vessel obstruction events

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    Background: Glioblastoma (GBM) is one of the most lethal tumor types. Hypercellular regions, named pseudo- palisades, are characteristic in these tumors and have been hypothesized to be waves of migrating glioblastoma cells.These “waves” of cells are thought to be induced by oxygen and nutrient depletion caused by tumor-induced blood vessel occlusion. Although the universal presence of these structures in GBM tumors suggests that they may play an instrumental role in GBM’s spread and invasion, the recreation of these structures in vitro has remained challenging. Methods: Here we present a new microfluidic model of GBM that mimics the dynamics of pseudopalisade forma- tion.To do this, we embedded U-251 MG cells within a collagen hydrogel in a custom-designed microfluidic device. By controlling the medium flow through lateral microchannels, we can mimic and control blood-vessel obstruction events associated with this disease. Results: Through the use of this new system, we show that nutrient and oxygen starvation triggers a strong migratory process leading to pseudopalisade generation in vitro.These results validate the hypothesis of pseudo- palisade formation and show an excellent agreement with a systems-biology model based on a hypoxia-driven phenomenon. Conclusions: This paper shows the potential of microfluidic devices as advanced artificial systems capable of mod- eling in vivo nutrient and oxygen gradients during tumor evolution

    Asociación entre los macronutrientes de la dieta y la obesidad en la infancia y adolescencia; un estudio de casos y controles

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    Introducción: La alta de prevalencia de obesidad infantil en España y sus posibles consecuencias hacen de esta enfermedad un problema prioritario de salud pública. Objetivo: Valorar, mediante un estudio epidemiológico analítico de casos y controles, la asociación entre la composición en macronutrientes de la dieta y la obesidad en una muestra de niños y adolescentes navarros de 5,5 a 18,8 años. Método: Se reclutaron 178 casos, niños y adolescentes obesos (índice de masa corporal > percentil 97) en Navarra. Los controles fueron emparejados individualmente según edad y sexo. Las medidas antropométricas fueron tomadas por personal entrenado utilizando métodos estandarizados. Se realizaron entrevistas individuales para recoger información sobre la frecuencia de consumo de alimentos mediante un cuestionario previamente validado a partir del que se calculó la ingesta de macronutrientes (hidratos de carbono, proteínas y grasas) y de los subtipos de grasas. Estos resultados se dividieron en quintiles de macronutrientes ajustados por ingesta energética total. Se realizó una regresión logística condicional para estimar odds ratios ajustadas de obesidad para cada uno de los cuatro quintiles superiores de consumo, usando el quintil inferior como referencia. Resultados: La composición de macronutrientes de la dieta era similar en casos y controles, excepto para las grasas poliinsaturadas, que se asociaron inversamente a la obesidad (p tendencia lineal < 0,01) con una odds ratio ajustada de 0,34 (IC 95%: 0,15 a 0,77) para el quinto quintil. Conclusiones: Nuestros resultados sugieren una asociación inversa entre una mayor ingesta de grasas poliinsaturadas y el riesgo de obesidad
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