4,367 research outputs found

    “Estudio de factibilidad de uso de sistema fotovoltáico para reducir costos de energía del fundo la Viña Batangrande, Chiclayo”

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    El presente trabajo de tesis denominado “Estudio de factibilidad de uso de sistema fotovoltaico para reducir costos de energía del fundo La Viña Batangrande, Chiclayo”, pretende responder la pregunta: ¿Si realizando un buen estudio de factibilidad de uso de un sistema fotovoltaico permitirá determinar la reducción de costos de energía en el fundo “La Viña” Batangrande, Chiclayo?, para ello se realiza una evaluación de la situación actual del fundo La Viña, determinando la potencia instalada y requerimiento de energía en un día, se analiza además el consumo energético de una motobomba y el costo de por galón de combustible fósil, para posteriormente reemplazarla por una electrobomba y compararlo con los costos de energía renovable fotovoltaica. Para efectos de obtención de energía solar, se toman en cuenta los datos proporcionados por instituciones con respaldo científico, pero además de ello se toman datos in situ de la radiación solar en W/m2, obtenido de un solarímetro digital modelo TES 1333. Se determinan los componentes electromecánicos que utilizará el sistema y se realiza una evaluación económica con el TIR y el VAN y la relación beneficio costo

    Soccer small-sided games activities vary according to the interval regime and their order of presentation within the session

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    In order to investigate the physical demands of widely used in soccer small-sided games (SSGs), we compared game variations performed under different interval (fixed or variable) and timing regimens (beginning or end of a training session). Twelve male players wore GPS devices during the SSGs to record total distance, relative distance, distance at different speeds, and maximum velocity variables. Four variations of SSGs (4x4) were randomly applied: beginning of a training session with fixed and variable recovery, or end of a training session with fixed and variable recovery. During the beginning or end of a training session settings with fixed recovery duration, 2-min of playing and 2-min of recovery were provided. During the beginning and end of a training session settings with variable recovery, athletes kept playing until a goal was scored, or up to 2-min if no goals were scored. Results were analysed using MANOVA. Total distance and relative distance were higher in the beginning compared to end of training sessions for both fixed and variable recovery duration (small to moderate effect sizes). Distance at various speed ranges (i.e., 13-18 km/h and >18 km/h) was higher (p = 0.01) at the beginning than at the end of training sessions with variable recovery. In addition, distance >18 km/h was higher at the beginning of a training session with variable recovery than fixed recovery and at the end of a training session with variable recovery than fixed recovery. In conclusion, several physical demand characteristics are affected by the moment of SSG application, while others respond to the recovery regime during SSGs, thus providing indications to the coaches to prescribe the intended training intensity by manipulating the context

    Tuning the antimicrobial behaviour of Cu 85 Zr 15 thin films in “wet” and “dry” conditions through structural modifications

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    The antimicrobial behaviour of Cu85Zr15 at.% thin films prepared by magnetron sputtering was studied in both wet and dry conditions. Small variations in key deposition processing parameters (pressure and substrate temperature) enabled the growth of thin films with similar nanostructures but different degrees of compactness, according to the Thornton's structural zone model. This model has proven its effectiveness in providing sensitive structural information to explain significant differences in antimicrobial behaviour of the CuZr thin films, even when processing conditions lie within the same structural zone. The antimicrobial behaviour has been studied for E. coli and S. aureus for up to 4 h of “dry” contact. Structures of lower compactness, grown at higher deposition pressure, are shown to provide higher antimicrobial activity for “dry” conditions than for “wet” conditions. For thin films of CuZr deposited at 0.5 Pa, the reduction percentage of bacteria is 99.47%, which is much higher than the results of 70–80% obtained for the films deposited at 0.1 and 0.3 Pa. Microscopy studies indicate that for 4 h of contact time, bacteria exhibit inner damage and even lysis, however, no morphological changes are detected because of the short timeframes used

    The moderating role of gender on entrepreneurial intentions: a TPB perspective

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    Purpose: To disentangle the ways in which social norms shape entrepreneurial intentions of university students and to analyse the moderating effect of gender that may arise. Design/methodology/approach: We have used the entrepreneurial intention model based on Theory of Planned Behaviour (TPB) literature and moderated by students’ gender affecting this intention. We tested some hypotheses using data from undergraduate business students in Spain and their entrepreneurial intentions. Findings: Our results suggest that perceived behavioural control and attitudes affect the entrepreneurial intentions of university students towards entrepreneurship while subjective norms do not. Furthermore, our findings reveal that the moderating effect of gender has a positive influence for women in the relationship between those subjective norms and the perceived behavioural control. However, as to some research done so far, the moderating role of gender does not seem to have a particular effect on predicting entrepreneurial intentions when moderating TPB dimensions.Practical implications: Given the socio-economic benefits attributed to entrepreneurship, the results allow the design of more effective education initiatives and policies. Originality/value: This research provides support for the application of the TPB, allowing for a better understanding of gender differences in entrepreneurial intentions.Peer Reviewe

    Predictive Models for Forecasting Public Health Scenarios: Practical Experiences Applied during the First Wave of the COVID-19 Pandemic

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    Background: Forecasting the behavior of epidemic outbreaks is vital in public health. This makes it possible to anticipate the planning and organization of the health system, as well as possible restrictive or preventive measures. During the COVID-19 pandemic, this need for prediction has been crucial. This paper attempts to characterize the alternative models that were applied in the first wave of this pandemic context, trying to shed light that could help to understand them for future practical applications. Methods: A systematic literature search was performed in standardized bibliographic repertoires, using keywords and Boolean operators to refine the findings, and selecting articles according to the main PRISMA 2020 statement recommendations. Results: After identifying models used throughout the first wave of this pandemic (between March and June 2020), we begin by examining standard data-driven epidemiological models, including studies applying models such as SIR (Susceptible-Infected-Recovered), SQUIDER, SEIR, time-dependent SIR, and other alternatives. For data-driven methods, we identify experiences using autoregressive integrated moving average (ARIMA), evolutionary genetic programming machine learning, short-term memory (LSTM), and global epidemic and mobility models. Conclusions: The COVID-19 pandemic has led to intensive and evolving use of alternative infectious disease prediction models. At this point it is not easy to decide which prediction method is the best in a generic way. Moreover, although models such as the LSTM emerge as remarkably versatile and useful, the practical applicability of the alternatives depends on the specific context of the underlying variable and on the information of the target to be prioritized. In addition, the robustness of the assessment is conditioned by heterogeneity in the quality of information sources and differences in the characteristics of disease control interventions. Further comprehensive comparison of the performance of models in comparable situations, assessing their predictive validity, is needed. This will help determine the most reliable and practical methods for application in future outbreaks and eventual pandemics

    Diminished fraction of blockable ATP-sensitive K+ channels in islets transplanted into diabetic mice

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    The reasons for the poor outcome of islet transplantation in diabetic patients are not well known; a better understanding of the pathophysiology of transplanted islets is needed. To study the mechanism coupling secretagogue stimuli with insulin release in transplanted islets, we determined the effects of glucose, tolbutamide, and carbamylcholine on the beta-cell membrane potential and cytosolic calcium concentrations ([Ca2+]i) of islets syngeneically transplanted into normal and streptozocin-induced diabetic mice. In both groups, normoglycemia was maintained after transplantation. Islets transplanted into normal recipients showed similar changes in beta-cell membrane potential and [Ca2+]i oscillations to those in control islets. In contrast, when islets were transplanted into diabetic mice, bursts of electrical activity were triggered at lower glucose concentrations (5.6 mmol/l) than in control islets (11 mmol/l), and maximal electrical activity was achieved at lower glucose concentrations (11 mmol/l) than in control islets (22 mmol/l). When membrane potential was plotted as a function of glucose concentration, the dose-response curve was shifted to the left. Compared with control islets, glucose-induced [Ca2+]i oscillations were broader in duration (22.3 +/- 0.6 s vs. 118.1 +/- 12.6 s; P < 0.01) and higher in amplitude (135 +/- 36 nmol/l vs. 352 +/- 36 nmol/l; P < 0.01). Glucose supersensitivity was attributed to a resting decrease in the fraction of blockable ATP-sensitive K+ (K+(ATP)) channels in transplanted islets that maintained normoglycemia with a limited beta-cell mass

    Influencia de los estilos de vida físicamente activos y sedentarios en la percepción subjetiva de la salud y el bienestar de la juventud española

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    La presente comunicación se enmarca en un estudio financiado por el Consejo Superior de Deportes (CSD) (Ref. 007/UPB10/12). Uno de los objetivos específicos del estudio, en el que se basa la comunicación, es ampliar el conocimiento sobre la influencia de los estilos de vida físicamente activos y sedentarios en la percepción subjetiva de la salud y el bienestar de la juventud española

    Prehospital emergency care of patients with acute heart failure in Spain: the SEMICA study (Emergency Medical Response Systems for Patients with Acute Heart Failure)

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    Objectives. To study the means of emergency transport used to bring patients with acute heart failure (AHF) to hospital emergency departments (EDs) and explore associations between factors, type of transport, and prehospital care received. Methods. We gathered the following information on patients treated for AHF at 34 Spanish hospital EDs: means of transport used (medicalized ambulance [MA], nonmedicalized ambulance [NMA], or private vehicle) and treatments administered before arrival at the hospital. Twenty-seven independent variables potentially related to type of transport used were also studied. Indicators of AHF severity were triage level assigned in the ED, need for admission, need for intensive care, in-hospital mortality, and 30-day mortality. Results. A total of 6106 patients with a mean (SD) age of 80 years were included; 56.5% were women, 47.2% arrived in PVs, 37.8% in NMAs, and 15.0% in MAs. Use of an ambulance was associated with female sex, age over 80 years, chronic obstructive pulmonary disease, a history of AHF, functional dependency, New York Heart Association class III-IV, sphincteral incontinence, labored breathing, orthopnea, cold skin, and sensory depression or restlessness. Assignment of a MA was directly associated with living alone, a history of ischemic heart disease, cold skin, sensory depression or restlessness, and high temperature; it was inversely associated with a history of falls. The rates of receipt of prehospital treatments and AHF severity level increased with use of MAs vs. NMAs vs. PV. Seventy-three percent of patients transported in MAs received oxygen, 29% received a diuretic, 13.5% a vasodilator, and 4.7% noninvasive ventilation. Conclusions. Characteristics of the patient with AHF are associated with the assignment of type of transport to a hospital ED. Assignment appears to be related to severity. Treatment given during MA transport could be increased

    IMPROV-ED study : outcomes after discharge for an episode of acute-decompensated heart failure and comparison between patients discharged from the emergency department and hospital wards

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    Objective To define the short-and mid-term outcomes of patients discharged after an episode of acute-decompensated heart failure (ADHF) and evaluate the differences between patients discharged directly from the emergency department (ED) and those discharged after hospitalization. Methods We performed a prospective, multicenter, cohort-designed study, including consecutive patients diagnosed with ADHF in 27 Spanish EDs. Thirty-four variables on epidemiology, comorbidity, baseline status, vital signs, signs of congestion, laboratory tests, and treatment were collected in every patient. The primary outcome was a combined endpoint of ED revisit (without hospitalization) or hospitalization due to ADHF, or all-cause death. Secondary outcomes were each of these three events individually. Outcomes were obtained by survival analysis at different timepoints in the entire cohort, and crude and adjusted comparisons were carried out between patients discharged directly from the ED and after hospitalization. Results Of the 3233 patients diagnosed with ADHF during a 2-month period, we analyzed 2986 patients discharged alive: 787 (26.4%) discharged from the ED and 2199 (73.6%) after hospitalization. The cumulative percentages of events for the whole cohort (at 7/30/180 days) for the combined endpoint were 7.8/24.7/57.8; for ED revisit 2.5/9.4/25.5; for hospitalization 4.6/15.3/40.7; and for death 0.9/4.3/16.8. After adjustment for patient profile and center, significant increases were found in the hazard ratios for ED-compared to hospital-discharged patients in the combined endpoint, ED revisit and hospitalization, being higher at short-term [at 7 days, 2.373 (1.678-3.355), 2.069 (1.188-3.602), and 3.071 (1.915-4.922), respectively] than at mid-term [at 180 days, 1.368 (1.160-1.614), 1.642 (1.265-2.132), and 1.302 (1.044-1.623), respectively]. No significant differences were found in death. Conclusions Patients with ADHF discharged from the ED have worse outcomes, especially at short term, than those discharged after hospitalization. The definition and implementation of effective strategies to improve patient selection for direct ED discharge are needed.Peer reviewe
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