Diseño de un convertidor elevador continua-continua para aplicaciones fotovoltaicas

Este trabajo presenta el diseño de un convertidor elevador de corriente continua a corriente continua cuyo objetivo es alimentar la etapa de potencia de un inversor fotovoltaico de dos etapas. Para elevar la tensión se diseño, simuló y posteriormente se fabricó un transformador de alta frecuencia que es gobernado por cuatro transistores IGBT conectados en la topología puente completo. La señal de alta frecuencia se genera mediante un circuito integrado que emplea la técnica de modulación por ancho de pulso. Se presentan las ecuaciones utilizadas en el proyecto y las mediciones obtenidas en laboratorio. Se concluye que el objetivo se cumplió satisfactoriamente.Fil: Serrano, V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Villena, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Cadena, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; Argentin

Postural evaluation and balance analysis in nordic skiing beginners

Se trata de un estudio de diseño transversal con evaluación del control postural antes-después de un curso de iniciación al esquí nórdico (5 jornadas, 6h/día), a un grupo experimental de 25 sujetos, participantes de la formación, y un grupo control de 8 sujetos. Se pretende evaluar el efecto de un entrenamiento inicial de esquí nórdico sobre el control postural en jóvenes deportistas. La estabilidad corporal se evaluó por medio de un test estabilométrico, calculando el área de desviación del centro de presiones por medio de una plataforma de fuerzas con sensores electrónicos. No se aprecian diferencias significativas en el grado de mejora del equilibrio entre el grupo experimental y el grupo control. Nuevos estudios con una mayor exigencia en la formación en esquí nórdico y un mayor número de sujetos en el grupo control son requeridosCross-sectional study with evaluation of postural control before and after a course of initiation to Nordic skiing (5 days, 6 hours per day). The sample consisted of an experimental group of 25 subjects participated in the training and a control group of 8 subjects. It is intended to evaluate the effect of initial training of Nordic skiing on postural control in young athletes. The physical stability was evaluated by a stabilometric test, calculating the deviation of the area of the center of pressures by the use of a force platform with electronic sensors. No significant differences were observed in the degree of improvement of the balance between the experimental group and the control group. New studies with a greater emphasis on training in Nordic skiing and a greater number of subjects in the control group are require

Draft Genome Sequence of a Probiotic Strain, Lactobacillus fermentum UCO-979C.

This report describes a draft genome sequence of Lactobacillus fermentum strain UCO-979C. The reads generated by a Ion Torrent PGM were assembled into contigs, with a total size of 2.01 Mb. The data were annotated using the NCBI GenBank and RAST servers. Specific features of the genome are highlighted

Caracterización y simulación de un módulo fotovoltaico amorfo con software libre

En este trabajo se presenta la simulación de un módulo de Silicio amorfo (a-Si). Se utiliza un software para cálculo científico orientado al cálculo numérico denominado Scilab. En este programa se implementa una función representativa del modelo y se presentan las curvas obtenidas para diferentes temperaturas. Los resultados se contrastan con las medidas iniciales de un panel del fabricante Solar Cell, concluyendo que el modelo se ajusta a lo esperado.In this paper the simulation of a (a-Si), amorphous silicon module is presented. Software for scientific computing oriented numerical calculation called Scilab is used. In this program a representative model function is implemented and the curves obtained for different temperatures are presented. The results are compared with the initial steps of a panel manufacturer Solar Cell, concluding that the model fits expected.Tema 8: Energías renovables, modelización y simulación.Facultad de Arquitectura y Urbanism

Caracterización y simulación de un módulo fotovoltaico amorfo con software libre

En este trabajo se presenta la simulación de un módulo de Silicio amorfo (a-Si). Se utiliza un software para cálculo científico orientado al cálculo numérico denominado Scilab. En este programa se implementa una función representativa del modelo y se presentan las curvas obtenidas para diferentes temperaturas. Los resultados se contrastan con las medidas iniciales de un panel del fabricante Solar Cell, concluyendo que el modelo se ajusta a lo esperado.In this paper the simulation of a (a-Si), amorphous silicon module is presented. Software for scientific computing oriented numerical calculation called Scilab is used. In this program a representative model function is implemented and the curves obtained for different temperatures are presented. The results are compared with the initial steps of a panel manufacturer Solar Cell, concluding that the model fits expected.Tema 8: Energías renovables, modelización y simulación.Facultad de Arquitectura y Urbanism

Caracterización y simulación de un módulo fotovoltaico amorfo con software libre

En este trabajo se presenta la simulación de un módulo de Silicio amorfo (a-Si). Se utiliza un software para cálculo científico orientado al cálculo numérico denominado Scilab. En este programa se implementa una función representativa del modelo y se presentan las curvas obtenidas para diferentes temperaturas. Los resultados se contrastan con las medidas iniciales de un panel del fabricante Solar Cell, concluyendo que el modelo se ajusta a lo esperado.In this paper the simulation of a (a-Si), amorphous silicon module is presented. Software for scientific computing oriented numerical calculation called Scilab is used. In this program a representative model function is implemented and the curves obtained for different temperatures are presented. The results are compared with the initial steps of a panel manufacturer Solar Cell, concluding that the model fits expected.Tema 8: Energías renovables, modelización y simulación.Facultad de Arquitectura y Urbanism

Predicting no-show appointments in a pediatric hospital in Chile using machine learning

The Chilean public health system serves 74% of the country’s population, and 19% of medical appointments are missed on average because of no-shows. The national goal is 15%, which coincides with the average no-show rate reported in the private healthcare system. Our case study, Doctor Luis Calvo Mackenna Hospital, is a public high-complexity pediatric hospital and teaching center in Santiago, Chile. Historically, it has had high no-show rates, up to 29% in certain medical specialties. Using machine learning algorithms to predict no-shows of pediatric patients in terms of demographic, social, and historical variables. To propose and evaluate metrics to assess these models, accounting for the cost-effective impact of possible intervention strategies to reduce no-shows. We analyze the relationship between a no-show and demographic, social, and historical variables, between 2015 and 2018, through the following traditional machine learning algorithms: Random Forest, Logistic Regression, Support Vector Machines, AdaBoost and algorithms to alleviate the problem of class imbalance, such as RUS Boost, Balanced Random Forest, Balanced Bagging and Easy Ensemble. These class imbalances arise from the relatively low number of no-shows to the total number of appointments. Instead of the default thresholds used by each method, we computed alternative ones via the minimization of a weighted average of type I and II errors based on cost-effectiveness criteria. 20.4% of the 395,963 appointments considered presented no-shows, with ophthalmology showing the highest rate among specialties at 29.1%. Patients in the most deprived socioeconomic group according to their insurance type and commune of residence and those in their second infancy had the highest no-show rate. The history of non-attendance is strongly related to future no-shows. An 8-week experimental design measured a decrease in no-shows of 10.3 percentage points when using our reminder strategy compared to a control group. Among the variables analyzed, those related to patients’ historical behavior, the reservation delay from the creation of the appointment, and variables that can be associated with the most disadvantaged socioeconomic group, are the most relevant to predict a no-show. Moreover, the introduction of new cost-effective metrics significantly impacts the validity of our prediction models. Using a prototype to call patients with the highest risk of no-shows resulted in a noticeable decrease in the overall no-show rate.</p

Adenosine Deaminase Activity Is a Sensitive Marker for the Diagnosis of Tuberculous Pleuritis in Patients with Very Low CD4 Counts

Background: Adenosine Deaminase Activity (ADA) is a commonly used marker for the diagnosis of tuberculous pleural effusion. There has been concern about its usefulness in immunocompromised patients, especially HIV positive patients with very low CD4 counts. The objective of this study was to evaluate the sensitivity of ADA in pleural fluid in patients with low CD4 counts. Materials and Methods: This was a retrospective case control study. Medical files of patients with tuberculous pleuritis and non-tuberculous pleuritis were reviewed. Clinical characteristics, CD4 cell counts in blood and biochemical markers in pleural fluid, including ADA were recorded. Results: One ninety seven tuberculous pleuritis and 40 non- tuberculous pleuritis patients were evaluated. Using the cut-off value of 30 U/L, the overall sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of ADA was 94%, 95%, 19, and 0.06 respectively. The mean CD4 cell counts among TB pleuritis patients was 29 and 153 cells/microL in patients with CD4 ,50 cells/microL and .50 cells/microL, (p,0.05) respectively. The corresponding mean ADA values for these patients were 76 U/L and 72 U/L respectively (p.0.5). There was no correlation between ADA values and CD4 cell counts (r =20.120, p = 0.369). Conclusion: ADA analysis is a sensitive marker of tuberculous pleuritis even in HIV patients with very low CD4 counts in a high TB endemic region. The ADA assay is inexpensive, rapid, and simple to perform and is of great value for the immediate diagnosis of tuberculous pleuritis while waiting for culture result and this has a positive impact on patient outcome

Untangling drivers for supplier environmental and social responsibility:An investigation in Philips Lighting's Chinese supply chain

This study unpacks the environmental and social dimensions of supplier responsibility and links each dimension to distinct drivers. Using stakeholder theory and the relational view, we distinguish between two main drivers: stakeholder pressures (i.e., from regulatory agencies, buying firms, and nongovernmental organizations) and relational mechanisms offered by multinational companies (MNCs) (i.e., lean trainings and relational capital). We used a multi-method research design to study how these drivers uniquely influence supplier responsibility in an emerging-country context. An in-depth case study with Philips Lighting and 10 of its Chinese suppliers reveals causal inferences that link stakeholder and relational drivers with each responsibility dimension (environmental vs. social). Audit and survey data from Philips Lighting's 134 Chinese suppliers, complemented with four archival databases, bolster these inferences. Overall, the results show that supplier environmental responsibility can be fostered through both stakeholder pressures and relational drivers; whereas, supplier social responsibility is much harder to address. The integrated methods offer a fuller, more comprehensive understanding of the specifics of supplier responsibility in China and also provide recommendations for MNCs that seek to improve it

Registry of people with diabetes in three Latin American countries : a suitable approach to evaluate the quality of health care provided to people with type 2 diabetes

Q2Q2Aims: To implement a patient registry and collect data related to the care providedto people with type 2 diabetes in six specialized centers of three Latin Americancountries, measure the quality of such care using a standardized form (QUALIDIAB)that collects information on different quality of care indicators, and analyze thepotential of collecting this information for improving quality of care and conductingclinical research. Methods: We collected data on clinical, metabolic and therapeu-tic indicators, micro- and macrovascular complications, rate of use of diagnosticand therapeutic elements and hospitalization of patients with type 2 diabetes in sixdiabetes centers, four in Argentina and one each in Colombia and Peru. Results:We analyzed 1157 records from patients with type 2 diabetes (Argentina, 668;Colombia, 220; Peru, 269); 39 records were discarded because of data entry errorsor inconsistencies. The data demonstrated frequency performance deficiencies inseveral procedures, including foot and ocular fundus examination and variouscardiovascular screening tests. In contrast, HbA1cand cardiovascular risk factorassessments were performed with a greater frequency than recommended by inter-national guidelines. Management of insulin therapy was sub-optimal, and deficien-cies were also noted among diabetes education indicators. Conclusions: Patientregistry was successfully implemented in these clinics following an interactiveeducational program. The data obtained provide useful information as to deficien-cies in care and may be used to guide quality of care improvement efforts.https://orcid.org/0000-0002-6860-3620N/