376 research outputs found

    A metaheuristic approach for the repositioning problem in bike sharing systems (bss): a study case in Toluca, México

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    The impact of Bike Sharing Systems (BSS) in the world had experienced such success that nowadays most iconic cities in the world have adopted its own system. The particular characteristics of the user’s mobility in every city have not allowed developing a generalized procedure to operate the systems. Moreover, the lack of symmetry in the mobility patterns, and the dynamic users’ behavior lead to eventually “unbalance” the system, this is, to a lack of bikes at stations, and therefore bikes have to be repositioned to stations where effective demand is present, and there is no unified or scientifically supported methodology. In this paper we deal with a study case in Toluca city (Huizi system), in which the entity in charge of current operational activities wants to design a procedure scientifically based to perform repositioning daily activities at the minimum operational cost guarantying the availability of bikes for the users (service level). Due to operational requirements, this bi-objective problem was formulated using a dynamic scope and stated as a combinatorial optimization model and finally solved using a multi-objective evolutionary algorithm

    Students frequently ask: ‘Yes but...What is the utility of physics?’

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    Two Teaching Innovation Projects were carried out in the framework of the subjects ‘Physics I’ and ‘Physics II’ for different Degrees on Engineering at the Engineering High School of the University of Cadiz, Spain, during the 2013-2014 course. The aim of these Projects was to catch the interest of first course students on physical phenomena and principles, a matter frequently considered as ‘difficult’ or even ‘boring’ for them when it is approached from an excessively formal scope. The methodology of the two Projects was based on experiments of Recreational Physics, different toys and devices, and other resources as posters, books and online contents. The Projects were conducted during Theory, Laboratory, and Online classes of Physics I and II, and their results were evaluated from questionnaires to the students. Main conclusions derived from them were: i) a significant increment on the interest of students on Physics and Science; ii) the aim of students for learning more about this kind of recreational physical experiments; and iii) a general sensation of enjoying the study and analysis of physical phenomena by students –and teachers as well–. In addition, students manifested their interest in this methodology to be applied to other Engineering subjects of their Degrees

    Survival of lichens and bacteria exposed to outer space conditions - Results of the Lithopanspermia experiments

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    n the space experiments Lithopanspermia, experimental support was provided to the likelihood of the lithopanspermia concept that considers a viable transport of microorganisms between the terrestrial planets by means of meteorites. The rock colonising lichens Rhizocarpon geographicum and Xanthoria elegans, the vagrant lichen Aspicilia fruticulosa, and endolithic and endoevaporitic communities of cyanobacteria and bacteria with their natural rock substrate were exposed to space for 10 days onboard the Biopan facility of the European Space Agency (ESA). Biopan was closed during launch and re-entry. In addition, in the Stone facility, one sample of R. geographicum on its natural granitic substrate was attached at the outer surface of the re-entry capsule close to the stagnation point, only protected by a thin cover of glass textolite. Post-flight analysis, which included determination of the photosynthetic activity, LIVE/DEAD staining, and germination capacity of the ascospores, demonstrated that all three lichen were quite resistant to outer space conditions, which include the full spectrum of solar extraterrestrial electromagnetic radiation or selected wavelength ranges. This high resistance of the lichens to space appears to be due to their symbiotic nature and protection by their upper pigmented layer, the cortex. In contrast, the rock- or halite-inhabiting bacteria were severely damaged by the same exposure. After atmospheric re-entry, the granite of the Stone sample was transformed into a glassy, nearly homogenous material, with several friction striae. None of the lichen cells survived this re-entry process. The data suggest that lichens are suitable candidates for testing the concept of lithopanspermia, because they are extremely resistant to the harsh environment of outer space. The more critical event is the atmospheric re-entry after being captured by a planet. Experiments simulating the re-entry process of a microbe-carrying meteoroid did not show any survivors

    Propuesta de mejora del Sistema Interno de Garantía de Calidad de la Facultad de Medicina

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    La garantía de calidad en el ámbito universitario puede considerarse como la atención sistemática, estructurada y continua a las titulaciones ofertadas. La garantía de calidad se compromete a poner en marcha los medios que aseguren y demuestren la calidad de los programas formativos que se desarrollan en cada una de las titulaciones ofrecidas por la Universidad y así cumplir con la obligación que tiene con la sociedad. El presente proyecto nace como fruto de la responsabilidad adquirida para el cumplimiento de las funciones encomendadas y, con el objetivo de seguir adoptando una estrategia de mejora continua de la calidad de la docencia y satisfacción de los colectivos implicados en el proceso de enseñanza-aprendizaje (Profesorado, Estudiantes y PAS)

    The impact of surgical practice on oncological outcomes in robot-assisted radical hysterectomy for early-stage cervical cancer, Spanish National Registry

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    Minimal invasive surgery (MIS) has been associated with lower disease-free survival than open surgery among women who underwent radical hysterectomy for early-stage cervical cancer. However, the mechanisms by which MIS increases mortality in cervical cancer remain uncertain. We aimed to determine if surgical practice among centers using robotic surgery has an impact on oncological outcomes. We evaluated 215 women with early-stage cervical cancer (≤IB1 or IIA1, FIGO 2009) who underwent robot-assisted radical hysterectomy in five Spanish tertiary centers between 2009 and 2018. A higher surgical volume, higher participation in clinical trials, higher rate of MRI use for diagnosis, greater use of sentinel lymph node biopsies, and a favorable learning curve with low rates of early recurrences were observed for the centers with better oncological outcomes. These factors might have a significant impact on oncological outcomes in all surgical approaches. Abstract: This study aimed to assess whether surgical practice had a significant impact on oncological outcomes among women who underwent robot-assisted radical hysterectomy for early-stage cervical cancer (≤IB1 or IIA1, FIGO 2009). The secondary objective was to audit the pre-surgical quality indicators (QI) proposed by the European Society of Gynaecological Oncology (ESGO). The top 5 of 10 centers in Spain and Portugal were included in the analysis. The hospitals were divided into group A (n = 118) and group B (n = 97), with recurrence rates of 10%, respectively. After balancing both groups using the propensity score, the ORs for all events were higher and statistically significant for group B (recurrences OR = 1.23, 95% CI = 1.13-1.15, p-value = 0.001; death OR = 1.10, 95% CI = 1.02-1.18, p-value = 0.012; disease-specific mortality ORr = 1.11, 95% CI = 1.04-1.19, p-value = 0.002). A higher surgical volume, higher participation in clinical trials, higher rate of MRI use for diagnosis, greater use of sentinel lymph node biopsies, and a favorable learning curve with low rates of early recurrences were observed among the centers with better oncological outcomes. These factors might have a significant impact on oncological outcomes not only after robot-assisted surgery, but also after laparoscopies and open surgeries in the treatment of cervical cancer

    Daño cardiaco frente a hepático por consumo de bebidas energizantes en ratas cepa Holtzman

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    RESUMENObjetivo: El consumo de bebidas energéticas (BE) está aumentando principalmente en jóvenes, debido a que promete mejorar el estado de alerta, el rendimiento físico y cognitivo y evita la fatiga. En nuestro país, una BE tiene alta concentración de cafeína y azúcar por botella, y es altamente comercializada y barata. Sin embargo, las BE tienen efectos adversos como complicaciones cardiovasculares, neurales y gastrointestinales. Los estudios indican un mayor daño en hígado y corazón, señalados por altos niveles séricos de GOT y daño tisular. El objetivo de nuestro estudio es determinar si el corazón o hígado, presenta más daño por consumo de BE en ratas Holtzman. Métodos: Se clasificaron 32 ratas Holtzman macho aleatoriamente en dos grupos con tratamientos diferentes por administración oral. El Grupo 1 (Control) recibió agua potable y el Grupo 2 (Experimental) recibió una bebida energética de 5,49 ml / 260 g; ambos grupos durante 30 días. Se proporcionó aclimatación previa y alimento. Durante el período experimental, hubo cuatro extracciones de sangre para análisis de GOT sérico. Se sacrificaron por exanguinación bajo anestesia obteniendo muestras de corazón e hígado. Resultados: Se encontró aumento de la concentración sérica de GOT en el grupo experimental comparado con el control. El análisis histológico que evaluó congestión vascular, necrosis y edema en ambos tejidos, reveló que el corazón tenía mayor daño que el hígado. Conclusión: El tejido cardiaco presenta mayor daño que el tejido hepático por consumo de BE en ratas Holtzman macho, manifestados por incremento de GOT y alteraciones histopatológicas.Palabras clave: Bebidas energéticas, transaminasas glutámicas oxaloacéticas (GOT), daño cardiaco, daño hepático. DOI: http://dx.doi.org/10.17268/rmt.2019.v14i03.0

    Lack of validation of genetic variants associated with anti-tumor necrosis factor therapy response in rheumatoid arthritis: a genome-wide association study replication and meta-analysis

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    Introduction: In this study, our aim was to elucidate the role of four polymorphisms identified in a prior large genome-wide association study (GWAS) in which the investigators analyzed the responses of patients with rheumatoid arthritis (RA) to treatment with tumor necrosis factor inhibitors (TNFi). The authors of that study reported that the four genetic variants were significantly associated. However, none of the associations reached GWAS significance, and two subsequent studies failed to replicate these associations. Methods: The four polymorphisms (rs12081765, rs1532269, rs17301249 and rs7305646) were genotyped in a total of 634 TNFi-treated RA patients of Spanish Caucasian origin. Four outcomes were evaluated: changes in the Disease Activity Score in 28 joints (DAS28) after 6 and 12 months of treatment and classification according to the European League Against Rheumatism (EULAR) response criteria at the same time points. Association with DAS28 changes was assessed by linear regression using an additive genetic model. Contingency tables of genotype and allele frequencies between EULAR responder and nonresponder patients were compared. In addition, we combined our data with those of previously reported studies in a meta-analysis including 2,998 RA patients. Results: None of the four genetic variants showed an association with response to TNFi in any of the four outcomes analyzed in our Spanish patients. In addition, only rs1532269 yielded a suggestive association (P = 0.0033) with the response to TNFi when available data from previous studies were combined in the meta-analysis. Conclusion: Our data suggest that the rs12081765, rs1532269, rs17301249 and rs7305646 genetic variants do not have a role as genetic predictors of TNFi treatment outcomes

    Risk factors and outcome of COVID-19 in patients with hematological malignancies

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    Background: Prognostic factors of poor outcome in patients with hematological malignancies and COVID-19 are poorly defned. Patients and methods: This was a Spanish transplant group and cell therapy (GETH) multicenter retrospective observational study, which included a large cohort of blood cancer patients with laboratory-confrmed SARS-CoV-2 infection through PCR assays from March 1st 2020 to May 15th 2020. Results: We included 367 pediatric and adult patients with hematological malignancies, including recipients of autologous (ASCT) (n=58) or allogeneic stem cell transplantation (allo-SCT) (n=65) from 41 hospitals in Spain. Median age of patients was 64 years (range 1-93.8). Recipients of ASCT and allo-SCT showed lower mortality rates (17% and 18%, respectively) compared to non-SCT patients (31%) (p=0.02). Prognostic factors identifed for day 45 overall mortality (OM) by logistic regression multivariate analysis included age>70 years [odds ratio (OR) 2.1, 95% con‑ fdence interval (CI) 1.2-3.8, p=0.011]; uncontrolled hematological malignancy (OR 2.9, 95% CI 1.6-5.2, p20 mg/dL (OR 3.3, 95% CI 1.7-6.4, p<0.0001). In multivariate analysis of 216 patients with very severe COVID-19, treatment with azithromycin or low dose corticosteroids was associated with lower OM (OR 0.42, 95% CI 0.2-0.89 and OR 0.31, 95% CI 0.11-0.87, respectively, p=0.02) whereas the use of hidroxycloroquine did not show signifcant improvement in OM (OR 0.64, 95% CI 0.37-1.1, P=0.1). Conclusions: In most patients with hematological malignancies COVID-19 mortality was directly driven by older age, disease status, performance status, as well as by immune (neutropenia) parameters and level of infammation (high CRP). Use of azithromycin and low dose corticosteroids may be of value in very severe COVID-19

    Investigación en Matemáticas, Economía, Ciencias Sociales y Agronomía

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    Cada trabajo del libro incluye conclusiones para los interesados en las temáticas aludidas y en ellos nos enteramos de aspectos como los siguientes: - El mayor incremento del precio de los insumos como el maíz, sorgo y en menor medida desperdicio de pan, en relación con el menor crecimiento del precio del ganado en pie, dará como consecuencia un desabasto de carne bovina. - El agua es un recurso primordial en las zonas áridas y semiáridas de México, en tanto que su aporte limita la producción de la agricultura. En este estudio se observó que el precio real del agua es muy bajo en relación a otras zonas agrícolas del mundo. - Hoy en día en el país se consumen alrededor de 718 mil barriles diarios de gasolinas, un aproximado de 113.7 millones de litros, una cantidad tan grande que nuestro país se ve en la necesidad de importar cerca del 39 % de las gasolinas que consumimos. - Los jaliscienses radicados en Estados Unidos tienen una mayor capacidad de financiamiento del bienestar en la entidad, que el propio gobierno de ese estado. - México continuará basando sus finanzas públicas y su política de desarrollo económico en la extracción de combustibles fósiles (petróleo). Este modelo acelerará el deterioro y agotamiento de los recursos naturales. -La importancia de la agricultura orgánica radica en que retoma los tres ámbitos de la sustentabilidad; el ámbito ambiental, el económico y el social. - Es fundamental motivar la organización de los productores de haba para que ellos puedan captar una mayor proporción de los altos márgenes de precios que los consumidores están dispuestos a pagar. - Las condiciones del clima afectan a la producción agraria. Debido al fenómeno de cambio climático, es necesario contar con herramientas informáticas que proporcionen información climatológica para poder tomar medidas preventivas a favor de una mayor cantidad y calidad de producción. La herramienta de software permite la consulta del clima por localidades evitando la necesidad de contar con una estación meteorológica
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