La investigación y producción de bioactivos vegetales de interés social, ambiental y económico en la región Centro-Oriental de Cuba

El estudio de las sustancias de origen vegetal para el desarrollo de fármacos y compuestos nutracéuticos, reviste una gran importancia en el contexto actual. La riqueza de compuestos biológicamente activos existente en plantas, justifica la necesidad de profundizar en su conocimiento y explotación sostenible. Los nutracéuticos constituyen un área de la ciencia en constante desarrollo, en la que se acepta el papel de componentes naturales no nutrientes que contribuyen a prevenir padecimientos crónicos y genéticos y reducir el riesgo de contraer enfermedades. De esta forma, ha aumentado el interés de las grandes industrias por la obtención de bioactivos vegetales con potencial terapéutico y la formulación de alimentos en base a los beneficios que sus componentes podrían tene

Saccharomyces cerevisiae glutaredoxin 5-deficient cells subjected to constitutive oxidizing conditions are affected in the expression of specific sets of genes

The Saccharomyces cerevisiae GRX5 gene codes for a mitochondrial glutaredoxin involved in the synthesis ofiron/sulfur clusters. Its absence prevents respiratory growth and causes the accumulation of iron inside cellsand constitutive oxidation of proteins. Null Δgrx5 mutants were used as an example of continuously oxidizedcells, as opposed to situations in which oxidative stress is instantaneously caused by addition of external oxidants.Whole transcriptome analysis was carried out in the mutant cells. The set of genes whose expression wasaffected by the absence of Grx5 does not significantly overlap with the set of genes affected in respiratorypetite mutants. Many Aft1-dependent genes involved in iron utilization that are up-regulated in a frataxin mutantwere also up-regulated in the absence of Grx5. BIO5 is another Aft1-dependent gene induced both upon irondeprivation and in Δgrx5 cells; this links iron and biotin metabolism. Other genes are specifically affected underthe oxidative conditions generated by the grx5 mutation. One of these is MLP1, which codes for a homologueof the Slt2 kinase. Cells lacking MLP1 and GRX5 are hypersensitive to oxidative stress caused by externalagents and exhibit increased protein oxidation in relation to single mutants. This in turn points to a role forMlp1 in protection against oxidative stress. The genes of the Hap4 regulon, which are involved in respiratorymetabolism, are down-regulated in Δgrx5 cells. This effect is suppressed by HAP4 overexpression. Inhibition ofrespiratory metabolism during continuous moderately oxidative conditions could be a protective response bythe cell

Drinking Water Fluoride Levels for a City in Northern Mexico (Durango) Determined Using a Direct Electrochemical Method and Their Potential Effects on Oral Health

Fluoride is ingested primarily through consuming drinking water. When drinking water contains fluoride concentrations >0.7 parts per million (ppm), consuming such water can be toxic to the human body; this toxicity is called “fluorosis.” Therefore, it is critical to determine the fluoride concentrations in drinking water. The objective of this study was to determine the fluoride concentration in the drinking water of the city of Durango. The wells that supply the drinking water distribution system for the city of Durango were studied. One hundred eighty-nine (189) water samples were analyzed, and the fluoride concentration in each sample was quantified as established by the law NMX-AA-077-SCFI-2001. The fluoride concentrations in such samples varied between 2.22 and 7.23 ppm with a 4.313 ± 1.318 ppm mean concentration. The highest values were observed in the northern area of the city, with a 5.001 ± 2.669 ppm mean value. The samples produced values that exceeded the national standard for fluoride in drinking water. Chronic exposure to fluoride at such concentrations produces harmful health effects, the first sign of which is dental fluorosis. Therefore, it is essential that the government authorities implement water defluoridation programs and take preventative measures to reduce the ingestion of this toxic halogen

La democracia venezolana en una encrucijada: las elecciones nacionales y regionales de 1998

[ES] El panorama político venezolano está sufriendo importantes cambios. El electorado ha roto con la estática estabilidad bipartidista que se logró en el llamado Pacto de Punto Fijo en 1958. En el artículo se exponen los antecedentes de orden político y económico de la transformación que se está desarrollando actualmente en la democracia venezolana. Se trata de un cambio que se ha mostrado a nivel electoral, donde nuevas fuerzas políticas sustituyen a los partidos tradicionales. La población ha perdido la confianza en los viejos partidos —Acción Democrática y COPEI— y las lealtades partidistas han desaparecido en favor de la personalización de la política y de la volatilidad del voto. En el artículo se describen los cambios en el sistema electoral y sus consecuencias; los partidos políticos y sus candidatos; el fenómeno de la abstención; los resultados de las elecciones para el Congreso de la República, y el proceso de elección presidencial.[EN] The political life in Venezuela is suffering important changes. The electorate has broken the static two-party stability achieved in 1958 with the so called Pacto de Punto Fijo. The article describes the changes in the electoral system and their consequences; political parties and their candidates; the phenomenon of abstention; the results of Congress elections and the process of presidential election.presents the political and economic background prior to the transformation that is actually taking place in the Venezuelan democracy. The change was manifest at the electoral level, where new political forces are substituting the traditional parties. The population has lost confidence in the old parties — Acción Democrática y COPEI — and party loyalties have disappeared in favor of the personalization of politics and the volatility of the vote

Teaching Using Collaborative Research Projects: Experiences with Adult Learners in Distance Education

[EN] This research studies the acquisition and improvement of specific cognitive, functional, and social competencies of the students enrolled in a university module in which we applied Collaborative Research Project (CRP) strategy. The module was Research Methodology for a master’s degree in research in electrical engineering, electronics and industrial control given at the National Distance Education University (UNED) in Spain. This practice was applied to a research project in which the private sector was interested in. We have been aiming at increasing academia–industry interaction while promoting active learning; both are principles advocated by the European Higher Education Area (EHEA). Having applied this strategy, the module learning outcomes were evaluated following the guideline standards set by the National Agency for Quality Assessment of Universities (ANECA) of the Spanish Government. The results from this evaluation indicated that CRP, even when carried out by using distance learning, has encouraged the students’ interest in both research and the module. It has also fostered collaboration between students and lecturers while increasing their degree of satisfaction. We highlight the difficulties in merging all the outcomes from the students’ research as the main drawback

Measuring the Quality of Model-Driven Projects with NDT-Quality

Model-driven web engineering (MDWE) is a new paradigm which provides satisfactory results in the development of web software systems. However, as can be concluded from several research works, MDWE provokes traceability problems and the necessity of managing constraints in metamodel instances and transformation executions. The management of these aspects is usually executed manually in the most of MDWE approaches. Nevertheless, model-driven paradigm itself can offer suitable ways to manage them. This chapter presents NDT-Quality, an approach to measure the quality of web projects developed with NDT (navigational development techniques), and offers a view about the application of this tool in real web projects.Ministerio de Educación y Ciencia TIN2007-67843-C06-03Ministerio de Educación y Ciencia TIN2007-30391-

Optimized design method for storage systems in photovoltaic plants with delivery limitation

Versión aceptada para publicación. No contiene los cambios menores recogidos tras el proof reading.[EN] It results widely common for distribution network operators to impose restrictions on delivered solar photovoltaic generated power when the power plant rated power is greater than the maximum allowed due to the distribution network capacity. Thus, a feasible solution to maximize the performance of the solar power plant is the integration of battery energy storage systems. Although this configuration has been extensively studied in the existing literature, an optimal design method to determine the proper size and operation of the energy storage system needs to be developed. In this paper, a novel method to help power plants designers to determine the optimal battery energy storage capacity to integrate into any solar photovoltaic power plant is provided. The proposed algorithm minimizes the potential power curtailment and optimizes the utilization rate of the batteries storage system. The algorithm can be applied to any grid connected solar photovoltaic power plant under delivery power restrictions, regardless of power capacity and location. The algorithm has been implemented to a simulated power plant with delivery limitations based in a real case, and results with the optimal battery capacity show that the system would be able to recover up to the 83% of the curtailed energy and a yearly average capacity utilization of 56%. Moreover, the BESS operation has been validated with a scaled model run in Simulink and laboratory measurements, achieving 98% of curtailed energy recovery rate and a 57% of average capacity utilization.[ES] Resulta muy habitual que los operadores de las redes de distribución impongan restricciones a la potencia generada por energía solar fotovoltaica suministrada cuando la potencia nominal de la central es superior a la máxima permitida debido a la capacidad de la red de distribución. Por ello, una solución factible para maximizar el rendimiento de la central solar es la integración de sistemas de almacenamiento de energía en baterías. Aunque esta configuración ha sido ampliamente estudiada en la literatura existente, es necesario desarrollar un método de diseño óptimo para determinar el tamaño y funcionamiento adecuados del sistema de almacenamiento de energía. En este trabajo se presenta un método novedoso para ayudar a los diseñadores de centrales eléctricas a determinar la capacidad óptima de almacenamiento de energía en baterías para integrar en cualquier central solar fotovoltaica. El algoritmo propuesto minimiza el posible recorte de potencia y optimiza la tasa de utilización del sistema de almacenamiento en baterías. El algoritmo puede aplicarse a cualquier planta de energía solar fotovoltaica conectada a la red bajo restricciones de potencia de entrega, independientemente de la capacidad de potencia y la ubicación. El algoritmo se ha aplicado a una central eléctrica simulada con limitaciones de suministro basada en un caso real, y los resultados con la capacidad óptima de las baterías muestran que el sistema sería capaz de recuperar hasta el 83% de la energía restringida y una utilización media anual de la capacidad del 56%. Además, el funcionamiento del BESS se ha validado con un modelo a escala ejecutado en Simulink y mediciones de laboratorio, y se ha conseguido recuperar el 98% de la energía restringida.S

A novel Multi‐Phase Flash Sintering (MPFS) technique for 3D complex‐shaped ceramics

This work demonstrates the first proof-of-concept of Multi-Phase Flash Sintering (MPFS). This novel tech nique essentially consists of applying a rotating electric field to the sample by means of a multi-phase voltage source as furnace temperature increases. Several ceramic materials with different types of elec trical conductivities are sintered within seconds at furnace temperatures much lower than those used for traditional DC flash sintering due to the higher power densities administered by a multi-phase power supply. Thus, ceramic materials are flashed at relatively lower applied voltages which minimizes un desired phenomena such as localization and preferential current pathways. Furthermore, MPFS allows diverse electrode configurations to promote a more uniform electric field distribution, enhancing the sin tering of 3D complex-shaped specimens. MPFS could be a true breakthrough in materials processing, as 3D complex-shaped specimens are homogeneously sintered at reduced temperatures, while keeping all the advantages of conventional flash sintering

Fluoride exposure effects and dental fluorosis in children in Mexico City

BACKGROUND The objective of the present study was to determine the prevalence and severity of dental fluorosis and to evaluate exposure to fluoridated products in students in the southwest part of the Federal District (Mexico City). MATERIAL AND METHODS Students between 10 and 12 years of age who were born and raised in the study zone were evaluated. The level of dental fluorosis was determined using the modified Dean index (DI) using criteria recommended by the World Health Organization (WHO). A bivariate analysis was performed with the χ2 test, and odds ratios (OR) and 95% confidence intervals (CI) are presented. Logistic regression was performed to evaluate the association between dental fluorosis and the independent variables. RESULTS A total of 239 students were evaluated. Their mean age was 11±0.82 years, and there were 122 (51%) males. Overall, dental fluorosis was found in 59% of participants; 29.3% had very mild fluorosis, 20.9% had mild fluorosis, 6.7% had moderate fluorosis, and 2.1% had severe fluorosis. The mean fluorosis score was 0.887±0.956. In the final logistic regression model, dental fluorosis was significantly associated with frequency of brushing (OR: 0.444; 95% CI: 0.297-0.666) and with the absence of parental supervision (OR: 0.636; 95% CI: 0.525-0.771). CONCLUSIONS The association found with frequency of brushing and lack of parental supervision may be contributing to the prevalence and severity of dental fluorosis