1,945 research outputs found

    Simulación de una cámara de combustión parauna microturbina de gas utilizando el programa de dinámica de fluidos fluent

    Get PDF
    En este artículo muestra los resultados de la simulación de una cámara de combustión diseñada y construida por estudiantes y docentes de la facultad de Ingeniería Mecánica de la Universidad Tecnológica de Pereira; integrantes del grupo de investigación de Sistemas Térmicos y Potencia mecánica. La cámara de combustión en cuestión, ha hecho parte de dos proyectos finales de grado de cuatro estudiantes de la facultad. El primero fue el diseño y construcción; el segundo de mejoras, pruebas y puesta a punto. La simulación fue realizada con el programa de dinámica de fluidos FLUENT y tiene como objeto principal validar los resultados obtenidos en los procesos de diseño y puesta a punto

    Simulación de una cámara de combustión parauna microturbina de gas utilizando el programa de dinámica de fluidos fluent

    Get PDF
    En este artículo muestra los resultados de la simulación de una cámara de combustión diseñada y construida por estudiantes y docentes de la facultad de Ingeniería Mecánica de la Universidad Tecnológica de Pereira; integrantes del grupo de investigación de Sistemas Térmicos y Potencia mecánica. La cámara de combustión en cuestión, ha hecho parte de dos proyectos finales de grado de cuatro estudiantes de la facultad. El primero fue el diseño y construcción; el segundo de mejoras, pruebas y puesta a punto. La simulación fue realizada con el programa de dinámica de fluidos FLUENT y tiene como objeto principal validar los resultados obtenidos en los procesos de diseño y puesta a punto

    Medication intensification in diabetes in rural primary care: a cluster-randomised effectiveness trial

    Get PDF
    OBJECTIVE: To determine the effectiveness of a provider-based intervention to improve medication intensification among patients with diabetes. DESIGN: Effectiveness cluster-randomised trial. Baseline and follow-up cross-sections of diabetes physicians\u27 patients. SETTING: Eleven U.S. Southeastern states, 2006-2008. PARTICIPANTS: 205 Rural primary care physicians, 95 completed the study. INTERVENTION: Multicomponent interactive intervention including web-based continuing medical education (CME), performance feedback and quality improvement tools. PRIMARY OUTCOME MEASURES: Medication intensification, a dose increase of an existing medication or the addition of a new class of medication for glucose, blood pressure and lipids control on any of the three most recent office visits. RESULTS: Of 364 physicians attempting to register, 102 were randomised to the intervention and 103 to the control arms; 95 physicians (intervention, n=48; control, n=47) provided data on their 1182 of their patients at baseline (intervention, n=715; control, n=467) and 945 patients at follow-up (intervention, n=479; control, n=466). For A1c control, medication intensification increased in both groups (intervention, pre 26.4% vs post 32.6%, p=0.022; control, pre 24.8% vs post 31.1%, p=0.033) (intervention, adjusted OR (AOR) 1.37; 95% CI 1.06 to 1.76; control, AOR 1.41 (95% CI 1.06 to 1.89)); however, we observed no incremental benefit solely due to the intervention (group-by-time interaction, p=0.948). Among patients with the worst glucose control (A1c \u3e9%), intensification increased in both groups (intervention, pre 34.8% vs post 62.5%, p=0.002; control, pre 35.7% vs post 61.4%, p=0.008). CONCLUSIONS: A wide-reach, low-intensity, web-based interactive multicomponent intervention had no significant incremental effect on medication intensification for control of glucose, blood pressure or lipids for patients with diabetes of physicians practising in the rural Southeastern USA. TRIAL REGISTRATION: NCT00403091

    Regional Motor Unit Firing Behaviors of Mono- and Bi-Articular Leg Extensor Muscles

    Get PDF
    Motor unit (MU) activation patterns provide vast insight into skeletal muscle contractions and may differ depending on architectural differences. Previous findings have suggested that MU activation patterns, specifically within the quadriceps group, are region-specific; this, along with the architectural differences between the quadriceps muscles, may further influence force production as reflected within the relationships between the firings. PURPOSE: To examine regional activation in proximal and distal regions of biarticular [rectus femoris (RF)] and monoarticular [vastus lateralis (VL)] knee extensors during submaximal isometric knee extensions. METHODS: On two separate randomized visits, eight lower-body resistance trained individuals, 6 males (n=6, age= 25.2 ±3.77) and 2 females (n=2, age= 21 ±1.4), performed submaximal isometric contractions at 30% and 70% of their maximal voluntary contractions (MVC) in a custom-built seat using an S-beam load-cell. Two separate 5-pin surface electromyography (EMG) sensors were used to record activation in the proximal and distal locations of either the VL or RF. Signals were recorded and decomposed into their constituent motor unit action potential (MUAP) trains, validated, and assessed for relative behavioral properties. For subsequent analysis of firing behaviors, the relationships (Slopes and intercepts) between motor unit action potential size (MUAPsize,) recruitment threshold (RT%), and mean firing rate (MFR) were calculated. Twelve separate two-way repeated measures analyses of variance (ANOVA) (location [proximal v distal] x muscle [VL v RF]) were used to compare slopes and intercepts of MFR vs. RT%, MUAPsize vs. RT%, and MFR vs. MUAPsize at both 30% and 70% MVC. RESULTS: There was a significant location x muscle interaction in the MFR v MUAPsize slopes during 30% MVC contraction (pCONCLUSION: The location by muscle interaction in the MFR v MUAPsize slopes during 30% MVC may indicate muscle fiber type distribution differences between sensor locations specifically, more type II fibers in the distal location of the VL

    Large-scale ocean connectivity and planktonic body size

    Get PDF
    Villarino, Ernesto ... et al.-- 13 pages, 5 figures, 5 tables, supplementary material https://dx.doi.org/10.1038/s41467-017-02535-8Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversityThis research was funded by the project Malaspina 2010 Circumnavigation Expedition (Consolider-Ingenio 2010, CSD2008-00077) and cofounded by the Basque Government (Department Deputy of Agriculture, Fishing and Food Policy). [...] E.V. was supported by a PhD Scholarship granted by the Iñaki Goenaga−Technology Centres FoundationPeer Reviewe

    Alternative Eco-Friendly Methods in the Control of Post-Harvest Decay of Tropical and Subtropical Fruits

    Get PDF
    The effectiveness on several fruits by the application of alternative methods against fungi is summarized in the present chapter. Several investigations have reported the efficacy of these technologies for controlling fungal infections. Currently, high post-harvest loses have been reported due to several factors such as inefficient management, lack of training for farmers, and problems with appropriate conditions for storage of fruits and vegetables. Even now, in many countries, post-harvest disease control is led by the application of chemical fungicides. However, in this time, awareness about fungi resistance, environmental, and health issues has led to the research of eco-friendly and effective alternatives for disease management. The pathogen establishment on fruits can be affected by the application of GRAS compounds like chitosan, essential oils, salts, among others; besides, their efficacy can be enhanced by their combination with other technologies like ultrasound. Thus, the applications of these alternatives are suitable approaches for post-harvest management of fruits

    Supply of essential and nonessential amino acids, proteins, antioxidants, iron and zinc from the main varieties of beans consumed in Mexico and their potential for biofortification

    Get PDF
    The objective of the present study was to characterize the contribution of essential and non-essential amino acids, protein, iron (Fe), and zinc (Zn) concentration, and antioxidant activity of the main bean varieties produced and consumed in Mexico. 23 varieties of beans were selected, and their amino acid profile, Fe and Zn concentration, protein and antioxidant activity were evaluated. The data obtained were subjected to an analysis of variance, test of separation of means and a correlation analysis. The results obtained indicate that the beans analyzed are an excellent source of essential amino acids (Histidine, threonine, valine, methionine, lysine, isoleucine, leucine and phenylalanine) and non-essential amino acids (Aspartic acid, serine, glutamic acid, glycine, alanine, proline, cysteine, tyrosine and arginine). The most prominent amino acids in Mexican bean varieties were: Glutamic acid, proline, aspartic acid, serine, lysine, and leucine. Regarding antioxidant activity, the most outstanding concentrations ranged from 91.18 to 96.76% inhibition. The bean varieties with the highest accumulation of amino acids, proteins, Fe, Zn and antioxidant activity were: 1) Black-eyed (23); 2) Peruvian (154); 3) Flor de Junio (150); 4) Pinto Saltillo (155). Finally, it was found that the common bean (Phaseolus vulgaris L.) is an excellent vehicle for the biofortification of Fe and Zn, which can contribute significantly to combat malnutrition problems and health of vulnerable communities in the urban and rural sectors of Mexico, as well as in the developing countries of the world
    corecore