A phenomenological-based dynamic model for a polymer electrolyte membrane fuel-cell humidifier assembly

This paper presents the deduction of a phenomenological-based semi-physical model (PBSM) for the gas humidification in a fuel-cell assembly. Unlike previously published models, the one proposed here includes the momentum transfer effects and their influences over simultaneous heat and mass transfers occurring into the process as a whole. These effects strongly affect the model precision due to the compressible characteristics of the air. High sensitivity of gas properties regarding changes in both pressure and temperature are also included by modelling the gas as a compressible fluid. The model reproduces the air–water vapour mixture behaviour from the compressor discharge to the fuel-cell inlet port. Since the air humidity and temperature conditions must be maintained at their set-points to guarantee an optimal fuel-cell performance, a model such as the one presented here can be used for designing any model-based control strategy towards achieving desirable operative conditions taking also into account the operational context of the considered assembly. The comparative assessment done with experimental data from a real test bench has shown the effectiveness of the proposed model in accurately reproduce the behaviour of such complex systems.Peer ReviewedPostprint (published version

RENDIMIENTO Y CALIDAD DE FORRAJE DE CUATRO CEREALES DE GRANO PEQUEÑO EN TRES ETAPAS DE CRECIMIENTO Y DOS NIVELES DE NITROGENO EN EL VALLE DE TOLUCA MEXICO

Tesis de licenciatura de Ia carrea de Ingeniero Agrónomo Fitotecnista en donde se estudió el efecto de la etapa de corte y la dosis de nitrógeno sobre el rendimiento y calidad nutricional de forraje en avena, cebada, triticale y trigoEn el valle de Toluca la producción de forraje se deriva principalmente de cultivos de cereales como son la avena y el maíz, establecidos bajo condiciones de temporal. Si bien la producción de forraje obtenida por estos cultivos cumple con la demanda para alimentación del ganado, no siempre está relacionado con la calidad nutricional requerida para optimizar dicho proceso. En el presente trabajo se evaluaron dos variedades de avena (Avemex y Karma), dos de cebada (Capuchona y Esmeralda), una variedad y una línea avanzada de triticale (Bicentenario y L3) y dos variedades de trigo (Baguette y Tollocan). El experimento se llevó a cabo en el ciclo primavera-verano 2015 en el valle de Toluca, México. La siembra se realizó el 26 de junio de 2015, con una densidad de siembra de 300 semillas por m2, bajo un diseño experimental de parcelas divididas en tiempo bajo un arreglo de bloques completos al azar con tres repeticiones, donde la parcela experimental constó de 4 surcos a doble hilera de 6 m de longitud con una separación de 80 cm entre surcos y 20 cm entre hileras. Se estudió el efecto de dos dosis de nitrógeno (60 y 120 kgN ha) y tres etapas fenológicas al corte (embuche, antesis y grano lechoso-masoso), sobre el rendimiento del forraje y algunos componentes de calidad nutricional en las tres etapas de corte mencionadas. La producción de materia seca y el contenido nutricional del forraje mejoró al aumentar la dosis de fertilización nitrogenada. El rendimiento de forraje se incrementó a medida que se retrasó la etapa de corte pero la calidad nutricional se vio disminuida conforme avanzó la madures de la planta. La L3 de triticale presentó mayor acumulación de biomasa en la etapa de grano lechoso-masoso (16.5 t ha-1), mientras que la variedad de trigo Baguette destacó en la etapa de embuche, ya que mostró el mejor comportamiento en los componentes de calidad nutricional de forraje, además de sobresalir por su alto contenido de proteína cruda incluso en la etapa de grano lechoso-masoso (103 g kg-1). Los resultados obtenidos indican que algunas de las variedades evaluadas pueden ser una opción viable para cumplir con la demanda de forraje con buena calidad para la alimentación de ganado lechero y de engorda en el valle de Toluca, México.UNIVERSIDAD AUTÓNOMA DEL ESTADO DE MÉXICO, FACULTAD DE CIENCIAS AGRÍCOLAS PROYECTO: Cambios en los Caracteres Ecofisiológicos del Rendimiento y Composición del Grano de Triticale en Función de la Disponibilidad de Nitrógeno Clave: 3793/2014/CI

Phenomenological based model of hydrogen production using an alkaline self-pressurized electrolyzer

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The aim of this work is to develop the phenomenological based modeling of a self-pressurized alkaline electrolyser with the objective of predicting the cross-contamination of the gases produced. A proposed model, built in Matlab®, represents the dynamical evolution in real electrolysers, and anticipates operational variables: level, pressure and all concentrations. Dynamic responses in the concentrations of the electrolytic cell, and variations in both level and pressure at the chamber due to the change in current and diffusivity, are reported. The equations by which the variables can be computed are also presented. The proposed model is ready for the corresponding adjustment of parameters based on experimental measurements taken from an available prototype and through a suitable identification process.Peer ReviewedPostprint (author's final draft

Comparison between logistic regression and neural networks to predict death in patients with suspected sepsis in the emergency room

INTRODUCTION: Neural networks are new methodological tools based on nonlinear models. They appear to be better at prediction and classification in biological systems than do traditional strategies such as logistic regression. This paper provides a practical example that contrasts both approaches within the setting of suspected sepsis in the emergency room. METHODS: The study population comprised patients with suspected bacterial infection as their main diagnosis for admission to the emergency room at two University-based hospitals. Mortality within the first 28 days from admission was predicted using logistic regression with the following variables: age, immunosuppressive systemic disease, general systemic disease, Shock Index, temperature, respiratory rate, Glasgow Coma Scale score, leucocyte counts, platelet counts and creatinine. Also, with the same input and output variables, a probabilistic neural network was trained with an adaptive genetic algorithm. The network had three neurone layers: 10 neurones in the input layer, 368 in the hidden layer and two in the output layer. Calibration was measured using the Hosmer-Lemeshow goodness-of-fit test and discrimination was determined using receiver operating characteristic curves. RESULTS: A total of 533 patients were recruited and overall 28-day mortality was 19%. The factors chosen by logistic regression (with their score in parentheses) were as follows: immunosuppressive systemic disease or general systemic disease (2), respiratory rate 24–33 breaths/min (1), respiratory rate ≥ 34 breaths/min (3), Glasgow Come Scale score ≤12 (3), Shock Index ≥ 1.5 (2) and temperature <38°C (2). The network included all variables and there were no significant differences in predictive ability between the approaches. The areas under the receiver operating characteristic curves were 0.7517 and 0.8782 for the logistic model and the neural network, respectively (P = 0.037). CONCLUSION: A predictive model would be an extremely useful tool in the setting of suspected sepsis in the emergency room. It could serve both as a guideline in medical decision-making and as a simple way to select or stratify patients in clinical research. Our proposed model and the specific development method – either logistic regression or neural networks – must be evaluated and validated in an independent population

Diagnosis and treatment for central Mucoepidermoid Carcinoma in the mandible : report of a clinical case in a young patient

A clinical case of a 13 year old male patient with a malignant tumor in the mandibular body area with two years of evolution and associated pain is reported. It was initially diagnosed as low grade central mucoepidermoid carcinoma through Hematoxylin and Eosin (H-E) staining in multiple biopsies. Considering the clinical and radiographic characteristics of the lesion, it was necessary to confirm the diagnosis through Periodic acid-Schiff (PAS). The treatment involved hemimandibulectomy, neck emptying, and complementary radiotherapy. This article aims to present a rare occurrence of this type of intraosseous malignant tumor of glandular origin in a young patient

Validation of the Edinburgh postpartum depression scale in a population of puerperal women in Mexico

BACKGROUND: The Edinburgh postnatal depression scale (EPDS) has been validated and used successfully in detecting postnatal depression in several language versions in a number of countries. However, there is not any Mexican version of the EPDS that had been validated. Therefore, we sought to validate a Spanish translated Mexican version of the EPDS in a population of puerperal Mexican women. METHODS: One hundred puerperal women within their three month postpartum period attending routine postnatal consultations in a public hospital in Durango City, Mexico participated in the study. The participants were divided into two groups: one group included 49 women with less than 4 weeks of postpartum, and the other group included 51 women within 4 to 13 weeks of postpartum. All participants submitted a Spanish translated Mexican version of the EPDS and were interviewed by a psychiatrist to assess major and minor depression by using DSM-IV criteria. RESULTS: Out of the 49 women with less than 4 weeks of postpartum, 4 were found as suffering from major depression and none from minor depression by using the DSM-IV criteria. In this group of women we found that the best EPDS score for screening depression was 11/12. This threshold showed a sensitivity of 75% (95% CI: 63.8–86.2), a specificity of 93% (95% CI: 84.6–100), a positive predictive value of 50%, a negative predictive value of 97.6%, and an area under the curve of 0.84. While in the 51 women within 4 to 13 weeks of postpartum, 7 were found as suffering from major depression and 1 from minor depression by using the DSM-IV criteria. In this group we found that the best EPDS score for screening depression was 7/8. This threshold showed a sensitivity of 75% (95% CI: 66.1–83.9), a specificity of 84% (95% CI: 76.1–91.9), a positive predictive value of 46.2%, a negative predictive value of 94.7% and an area under the curve of 0.80. CONCLUSION: The Mexican version of the EPDS can be considered for screening depression in puerperal Mexican women whenever cut-off scores of 11/12 and 7/8 in women with less than 4 weeks and within 4 to 13 weeks of postpartum are used, respectively

Active commuting is associated with a lower risk of obesity, diabetes and metabolic syndrome in Chilean adults

Background: There is limited evidence on how active commuting is associated with health benefits in developing countries. The aim of this study therefore was to investigate the associations between active commuting and markers of adiposity and cardiometabolic risk in the Chilean adult population. Methods: In total, 5157 participants from the Chilean National Health Survey 2009–10 were included in this cross-sectional study. Active commuting was measured using the Global Physical Activity Questionnaire (GPAQ v2). Body mass index (BMI) and waist circumference (WC) were measured and used to define obesity and central obesity. Type 2 diabetes (T2D) and metabolic syndrome were determined using WHO and updated ATPIII-NCEP criteria, respectively. Results: The main finding of this study is that a 30 min increase in active commuting is associated with lower odds for BMI &gt; 25.0 kg m−2 (0.93 [95% CI: 0.88–0.98, P = 0.010]). Similarly, the odds for central obesity was 0.87 [0.82–0.92, P &lt; 0.0001]. Similar associations were found for T2D (0.81 [0.75–0.88], P &lt; 0.0001) and metabolic syndrome (OR: 0.86 [0.80–0.92], P &lt; 0.0001). Conclusion: Our findings show that active commuting is associated with lower adiposity and a healthier metabolic profile including lower risk for obesity, diabetes and metabolic syndrome

Improving the automatic segmentation of subtitles through conditional random field

[EN] Automatic segmentation of subtitles is a novel research field which has not been studied extensively to date. However, quality automatic subtitling is a real need for broadcasters which seek for automatic solutions given the demanding European audiovisual legislation. In this article, a method based on Conditional Random Field is presented to deal with the automatic subtitling segmentation. This is a continuation of a previous work in the field, which proposed a method based on Support Vector Machine classifier to generate possible candidates for breaks. For this study, two corpora in Basque and Spanish were used for experiments, and the performance of the current method was tested and compared with the previous solution and two rule-based systems through several evaluation metrics. Finally, an experiment with human evaluators was carried out with the aim of measuring the productivity gain in post-editing automatic subtitles generated with the new method presented.This work was partially supported by the project CoMUN-HaT - TIN2015-70924-C2-1-R (MINECO/FEDER).Alvarez, A.; Martínez-Hinarejos, C.; Arzelus, H.; Balenciaga, M.; Del Pozo, A. (2017). Improving the automatic segmentation of subtitles through conditional random field. Speech Communication. 88:83-95. https://doi.org/10.1016/j.specom.2017.01.010S83958

Stercoraceous perforation, rare but potentially fatal cause: case report

Stercoraceous perforation is an infrequent pathology but with high mortality rates, it is increasingly recognized as a consequence of chronic constipation, it occurs in elderly people, the diagnosis is a surgical challenge, sudden abdominal pain is the initial symptom associated with signs of peritoneal irritation and the diagnostic study of choice is tomography, the treatment of choice is early surgery, the prognosis is related to the patient's comorbidities. We present the clinical case and review of the subject of a 72-year-old woman who presented stercoraceous perforation secondary to chronic constipation, emergency surgery was performed with resection of the affected bowel, colostomy and Hartmann's pouch with favorable short-term results

Joint effect of physical activity and sedentary behaviour on cardiovascular risk factors in Chilean adults

Background: To investigate the associations between combined categories of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with markers of adiposity and cardiovascular risk in adults. Methods: Overall, 5040 participants (mean age 46.4 years and 59.3% women) from the cross-sectional Chilean National Health Survey 2009–2010 were included in this study. MVPA and SB were measured using the Global Physical Activity questionnaire. Four categories were computed using MVPA- and SB-specific cut-offs (‘High-SB &#38; Active’, ‘Low-SB &#38; Active’, ‘High-SB &#38; Inactive’ and ‘Low-SB &#38; Inactive’). Results: Compared to the reference group (‘High-SB &#38; Inactive’), those in ‘High-SB &#38; Active’ and ‘Low-SB &#38; Active’ were less likely to have an obese BMI (OR: 0.67 [0.54; 0.85], P = 0.0001 and 0.74 [0.59; 0.92] P = 0.0007, respectively) and less likely to have metabolic syndrome (OR: 0.63 [0.49; 0.82], P &lt; 0.0001 and 0.72 [0.57; 0.91], P = 0.007), central obesity (OR: 0.79 [0.65; 0.96], P = 0.016 and 0.71 [0.59; 0.84], P &lt; 0.0001), diabetes (OR: 0.45 [0.35; 0.59], P &lt; 0.0001 and 0.44 [0.34; 0.56], P &lt; 0.0001) and hypertension (OR: 0.52 [0.43; 0.63], P &lt; 0.0001 and 0.60 [0.50; 0.72], P &lt; 0.0001), respectively. Conclusions: Being physically active and spending less time in SBs was associated with lower adiposity and improvements in cardiovascular risk factors