Numerical Investigation of Heat and Mass Transfer Phenomena in Boiling

Applications boiling are found in heat sinks for electronics cooling, nuclear and fossil fuel powered steam generators, distillation columns, concentrated solar power systems, glass melting furnaces, desalination chambers, and heat and mass exchangers. In order to increase the performance and safety margins of these applications, there is a need to develop tools that predict the thermal and fluid behavior during bubble growth. The analysis of boiling has been addressed by computer simulations, which employ methods for approximating mass and heat transfer at the interface. However, most simulations make assumptions that could adversely affect the prediction of the thermal and dynamic fluid behavior near the bubble-edge. These assumptions include: (i) computation of mass transfer with local temperature differences or with temperature gradients at cell-centers rather than with temperature gradients at the interface, (ii) modified discretization schemes at neighboring-cells or a transition region to account for the interface saturation temperature, and (iii) interface smearing or distribution of mass transfer into multiple cells around the interface to prevent interface deformations. The present work proposes methods to perform a simulation of nucleate boiling. The proposed methods compute mass transfer with temperature gradients at the interface, account for the interface saturation temperature, and model a sharp interface (interface within one cell) with mass transfer only at interface-cells. The proposed methods lead to a more realistic representation of the heat and mass transfer at the interface. Results of the simulation are in excellent agreement with theory on planar interface evaporation and growth of spherical bubbles in superheated liquid. In addition, numerical bubble growth rates compare well with experimental data on single bubble nucleation over a heated surface. The simulation of nucleate boiling with water and a 6.2 K wall superheat reveals large heat transfer coefficients over a 200 um distance from the interface. In addition, analyses of the wall shear stress indicate an influence region of two-times the departure bubble diameter

Gestión educativa y el manejo de conflictos en las instituciones educativas de la RED N° 6, Cercado de Lima, 2016

La investigación titulada: Gestión educativa y el manejo de conflictos en las Instituciones Educativas de la RED N° 6, Cercado de Lima, 2016, tuvo como objetivo general determinar la relación entre la gestión educativa y el manejo de conflictos en las Instituciones educativas de la RED N° 6, Cercado de Lima, 2016. El tipo de investigación fue sustantiva del nivel descriptivo, de enfoque cuantitativo; de diseño no experimental. La población censal estuvo conformada por 356 docentes, una muestra de 185 docentes, el tipo de muestreo fue probabilística estratificada. La técnica empleada para recolectar información fue encuesta y los instrumentos de recolección de datos fueron dos cuestionarios que fueron debidamente validados a través de juicios de expertos y determinando su confiabilidad a través del estadístico Alfa de Cronbach (0,953 y 0,925), que demuestra alta confiabilidad. Los resultados de la prueba de Rho de Spearman, en donde el valor del coeficiente de correlación es (r = 0.612) lo que indica una correlación positiva moderada, además el valor de P = 0,000 resulta menor al de P = 0,05 y en consecuencia la relación es significativa al 95% y se rechaza la hipótesis nula (Ho) asumiendo que existe relación positiva entre la gestión educativa y el manejo de conflictos en las Instituciones educativas de la RED N° 6, Cercado de Lima, 2016

Clinical Effects of Liraglutide in a Real-World Setting in Spain: eDiabetes-Monitor SEEN Diabetes Mellitus Working Group Study

Introduction: A limitation with randomized controlled trials is that, while they provide unbiased evidence of the efficacy of interventions, they do so under unreal conditions and in a very limited and highly selected patient population. Our aim was to provide data about the effectiveness of liraglutide treatment in a real-world and clinical practice setting. Methods: In a retrospective and observational study, data from 753 patients with type 2 diabetes were recorded through an online tool (eDiabetes-Monitor). Results: Mean baseline glycated hemoglobin (HbA1c) was 8.4 ± 1.4% and mean body mass index (BMI) was 38.6 ± 5.4 kg/m2. After 3–6 months of treatment with liraglutide, we observed a change in HbA1c of -1.1 ± 1.2%, -4.6 ± 5.3 kg in weight and -1.7 ± 2.0 kg/m

Perception and use of flywheel resistance training amongst therapists in sport

Flywheel (isoinertial) resistance training is a valid strength training method that has been incorporated in sport for decades, yet little is known about how therapists working in sport apply flywheel resistance training. We aimed to describe and understand current application and perception of flywheel resistance training amongst therapists working in sport. Seventy- three therapists (13 ± 10 years of experience) started part of this survey with 52 completing the entire electronic questionnaire. Nine multiple choice questions on application and perceptions of flywheel training (prerequisites, use of technology, barriers, and upper- and lower-body exercises) preceded two 6-point Likert scale statements on strength and reduction of injury likelihood. Most therapists (47/73) either used or intended to use flywheel training with their athletes and stated familiarisation would be a priority prior to initiating training. Although more than half suggested they were confident flywheel training could enhance strength (27/52) and muscular prehabilitation outcomes (40/52), many remained unsure. Nonetheless, it appears that therapists would mostly include flywheel training within prehabilitation (40/52) or during the later stages of rehabilitation (37/52). To monitor progress, therapists slightly prefer power (30/52) over velocity outputs, while few would not use them at all. Although therapists would prescribe most exercises - the squat, rotational exercise, and unilateral leg curl would be the most selected. Meanwhile, therapists reported remain most unsure or would avoid prescribing the lateral squat and unilateral hip extension. The biggest perceived barriers to flywheel training are equipment cost/space, evidence, and scheduling. The investigation provides valuable insight into the application and perception of flywheel training amongst therapists working in sport

Comparative study of human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC) as a treatment for retinal dystrophies

Retinal dystrophies (RD) are major causes of familial blindness and are characterized by progressive dysfunction of photoreceptor and/or retinal pigment epithelium (RPE) cells. In this study, we aimed to evaluate and compare the therapeutic effects of two pluripotent stem cell (PSC)-based therapies. We differentiated RPE from human embryonic stem cells (hESCs) or human-induced pluripotent stem cells (hiPSCs) and transplanted them into the subretinal space of the Royal College of Surgeons (RCS) rat. Once differentiated, cells from either source of PSC resembled mature RPE in their morphology and gene expression profile. Following transplantation, both hESC- and hiPSC-derived cells maintained the expression of specific RPE markers, lost their proliferative capacity, established tight junctions, and were able to perform phagocytosis of photoreceptor outer segments. Remarkably, grafted areas showed increased numbers of photoreceptor nuclei and outer segment disk membranes. Regardless of the cell source, human transplants protected retina from cell apoptosis, glial stress and accumulation of autofluorescence, and responded better to light stimuli. Altogether, our results show that hESC- and hiPSC-derived cells survived, migrated, integrated, and functioned as RPE in the RCS rat retina, providing preclinical evidence that either PSC source could be of potential benefit for treating RD

Hydraulic Traits Emerge as Relevant Determinants of Growth Patterns in Wild Olive Genotypes Under Water Stress

The hydraulic traits of plants, or the efficiency of water transport throughout the plant hydraulic system, could help to anticipate the impact of climate change and improve crop productivity. However, the mechanisms explaining the role of hydraulic traits on plant photosynthesis and thus, plant growth and yield, are just beginning to emerge. We conducted an experiment to identify differences in growth patterns at leaf, root and whole plant level among four wild olive genotypes and to determine whether hydraulic traits may help to explain such differences through their effect on photosynthesis. We estimated the relative growth rate (RGR), and its components, leaf gas exchange and hydraulic traits both at the leaf and whole-plant level in the olive genotypes over a full year. Photosynthetic capacity parameters were also measured. We observed different responses to water stress in the RGRs of the genotypes studied being best explained by changes in the net CO2 assimilation rate (NAR). Further, net photosynthesis, closely related to NAR, was mainly determined by hydraulic traits, both at leaf and whole-plant levels. This was mediated through the effects of hydraulic traits on stomatal conductance. We observed a decrease in leaf area: sapwood area and leaf area: root area ratios in water-stressed plants, which was more evident in the olive genotype Olea europaea subsp. guanchica (GUA8), whose RGR was less affected by water deficit than the other olive genotypes. In addition, at the leaf level, GUA8 water-stressed plants presented a better photosynthetic capacity due to a higher mesophyll conductance to CO2 and a higher foliar N. We conclude that hydraulic allometry adjustments of whole plant and leaf physiological response were well coordinated, buffering the water stress experienced by GUA8 plants. In turn, this explained their higher relative growth rates compared to the rest of the genotypes under water-stress conditions

The Fourth International Neonatal and Maternal Immunization Symposium (INMIS 2017): Toward Integrating Maternal and Infant Immunization Programs.

Prevention of serious infections in pregnant mothers, newborns, and young infants through immunization during pregnancy and in early life has the potential to further reduce maternal and neonatal morbidity and mortality worldwide. In the past decade, research in this field has advanced substantially, from the understanding of the biology and immunology of pregnancy and early life, to the active development of several candidate vaccines, for which challenges and opportunities for global implementation are under consideration. Experts from academia, industry, regulatory and funding agencies, public health, and international organizations met in Brussels (Belgium) from 10 to 12 September 2017, at the 4th International Neonatal and Maternal Immunization Symposium (INMIS), to review the most relevant advances in maternal and neonatal immunization. The overarching focus of the conference was to identify the path forward to achieve integration of maternal and early life immunization strategies for the successful implementation of vaccines in antenatal care and pediatric programs for reduction of maternal and infant mortality worldwide.IMPORTANCE This report provides an overview of the proceedings of the 4th International Maternal and Neonatal Immunization Symposium, where presentations focused on the state-of-the-art research on the development and implementation of vaccines given during pregnancy for the protection of mothers and infants