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Retinoblastoma is the most common malignant intraocular tumor in children. Y79 human retinoblastoma cells are in vitro models of retinal tumors used for drug screening. Undifferentiated Y79 cells originate from a primitive multi-potential neuroectodermal cell and express neuronal and glial properties. However, the nature of cellular heterogeneity in Y79 cells is unclear because functional methods to characterize neurons or glial cells have not been employed to Y79 cells. Here, we perform patch-clamp recordings to characterize electrophysiological properties in retinoblastoma cells. We identified a population of large-sized Y79 cells (i.e., giant cells, ~ 40-µm diameter), hyperpolarized resting membrane potential (–54 mV), and low input resistance (~ 600 MΩ), indicating electrically mature cells. We also found that giant Y79 cells contain increased density of T-type calcium channels. Finally, we found that T-type calcium channels are active only in giant cells suggesting that cancer treatments aimed to prevent calcium influx in retinoblastomas should be tested in giant cells.

La globalización implica para los países de la región grandes oportunidades y desafíos. La idea de que el planeta es una “aldea global” es una visión que está en vigencia en este siglo. La globalización ha traído consigo efectos positivos como la socialización a nivel mundial de ideas sobre el respeto a los derechos humanos y el valor que tiene la democracia en el desarrollo de los países. El proceso de globalización está integrando económicamente a los países, por este motivo en los últimos años han surgido productores de bienes y servicio a escala mundial, que ofrecen sus productos cada vez más integrados y más homogéneos. Por lo tanto esta tesis se enfoca en analizar los problemas del área de producción de Procarsa que evitan que esta empresa sea competitiva en el mercado. A lo largo de la tesis se analizará que los principales problemas de esta empresa, la cual deducira que no ha renovado su maquinaria hace más de 30 años, y cuenta con equipos de hasta 47 años de antigüedad. A pesar de tener un eficiente mantenimiento se presentan inconvenientes en planta, y requiere que llegue la hora del recambio, para estar a la altura de la globalización y ser competitivo en el mercado. Se analizara mediante la herramienta del cuestionario donde está el problema crítico de la empresa. Por lo tanto se presentara como solución la innovación tecnológica, quedando como punto pendiente la aplicación de esta solución que puede ser suficientemente sustentado con herramientas de ingeniería económica. Se espera que implementada la solución la empresa sea líder en la región.

Las enfermedades transmitidas por alimentos constituyen, a nivel mundial, uno de los problemas más generalizados y de mayor repercusión sobre la salud de personas, afectando generalmente a la población de bajos recursos, niños, mujeres embarazadas y ancianos. La presente revisión no pretende sentar cátedra sobre el análisis de las enfermedades producidas por alimentos, más bien está pensado como una etapa más de un proceso necesario y permanente, en la promoción y prevención de dicha patología.

Purpose The purpose of this paper is to assess the strategies for improving the competitiveness of Ecuador (ECU), Colombia (COL) and Peru (PER). It is one of the first studies using 36 indicators within the context of three South-American countries. It fulfills the lack of knowledge at the scientific work and its practical objective by identifying the factors that public policy may take into consideration urgently to improve the global competitiveness level of the countries for a sustainable development and considerations for a long-term integration. Design/methodology/approach It analyzes data of four-year average of international sources such as: The International Monetary Fund, The World Bank, The United Nations, among others. The factors were selected after a careful literature review, the final selection and the weight of each determinant was calculated using partial least squares-structural equation modeling. The calculation of the national and international competitiveness indexes used the double diamond for competitiveness theoretical frame. Findings From a national perspective, it was found that COL is the most competitive country followed by PER in the second place and ECU is in third. Internationally, the authors have found also that COL is the most competitive economy, PER in second place and ECU is in third. Research limitations/implications This study has found that in order to improve the level of national competitiveness, ECU has to concentrate on improving and strengthening formal and non-formal institutions, which are reflected in: four factors, PER four, and COL three. To reach international competitiveness, ECU should improve four factors, PER five, and COL five formal and non-formal institutions. Practical implications This research is the first one on its field, it uses 36 competitiveness indexes and the PLS-SEM statistic methodology to assign the weight of competitive indicators and the DD theoretical frame to determine the relevance of its factors and it is oriented to advise decision-makers and provides the appropriate police guidelines for the national competitiveness strategy and improve their quality of life of its residents from: ECU-COL-PER. On the other hand, the academic implications of these results appear when calculating the weight-load competitiveness indexes using inferential multivariate analysis; it provides researchers and practitioners an analysis tool for comparing competitive factors of emerging countries from the DD approach without any weaknesses, as a framework to assist in formulating economic policy at the national and regional level. Social implications Due to the difficulty of competitiveness operationalization, this research uses PLS-SEM to correlate its factors as the statistical methodology and the DD as the tool for the identification of theoretical indicators. This work may be taken into consideration for an immediate and sustainable improvement in order to win competitiveness than its neighbors. Originality/value This study is unique because the factors were selected after a careful literature review; the final selection and the weight of each determinant was calculated using PLS-SEM. The calculation of the national and international competitiveness indexes used the DD for competitiveness theoretical framework applied for the first time in a research for South America with 36 determinants. The result of this analysis compares the weak and strong determinants of these three member countries of UNASUR for the development of their complementarities and therefore the recommendations of public policy.

Purpose Using a proposed model, the purpose of this paper is to categorize small and medium enterprises’ (SMEs) owners/managers’ perceptions of customer service, and of the manifestations and observable behaviors in relation to the most frequent repercussions of domestic violence in the workplace. Design/methodology/approach A sample of 73 SME owners/managers was selected; a survey with 44 variables was used for data collection; and factorial and canonical analysis techniques were used to analyze the data. Findings The following were found: among the most frequent manifestations of domestic violence in SME customer services, there are four categories that explain 69.46 percent of the model of variance: threats and continuous absences, frequent mistakes and bad relationships, physical damage/lack of concentration and negative manifestation with low self-esteem; among observable behavior at the workplace, there are four categories that explain 65.35 percent of the model of variance: lack of concentration/tearfulness, fear/insecurity, limited attention to customers and continuous threats; finally there is a 96.70 percent probability of the SMEs’ productivity being affected (loss of customers and low production), through three manifestations of domestic violence detected in the employees: tiredness, sleepiness and tearfulness. Research limitations/implications This research is circumscribed to only one geographical zone in Puerto Rico. Practical implications Even only three manifestations of domestic violence in workers will significantly decrease productivity. When SME managers detect these, they can take action to mitigate the problem for the benefit of the workers. Originality/value This study is a pioneer proposal in its analytical quantitative approach on domestic violence in Puerto Rico and its repercussions on the productivity of the service sector, using canonical analysis.

Pattern separation is a fundamental brain computation that converts small differences in synaptic input patterns into large differences in action potential (AP) output patterns. Pattern separation plays a key role in the dentate gyrus, enabling the efficient storage and recall of memories in downstream hippocampal CA3 networks. Several mechanisms for pattern separation have been proposed, including expansion of coding space, sparsification of neuronal activity, and simple thresholding mechanisms. Alternatively, a winner-takes-all mechanism, in which the most excited cells inhibit all less-excited cells by lateral inhibition, might be involved. Although such a mechanism is computationally powerful, it remains unclear whether it operates in biological networks. Here, we develop a full-scale network model of the dentate gyrus, comprised of granule cells (GCs) and parvalbumin+ (PV+) inhibitory interneurons, based on experimentally determined biophysical cellular properties and synaptic connectivity rules. Our results demonstrate that a biologically realistic principal neuron–interneuron (PN–IN) network model is a highly efficient pattern separator. Mechanistic dissection in the model revealed that a winner-takes-all mechanism by lateral inhibition plays a crucial role in pattern separation. Furthermore, both fast signaling properties of PV+ interneurons and focal GC–interneuron connectivity are essential for efficient pattern separation. Thus, PV+ interneurons are not only involved in basic microcircuit functions, but also contribute to higher-order computations in neuronal networks, such as pattern separation.

Recently, great attention has been given to microbial fuel cells (CCM) due to their moderate operating conditions and the use of a variety of biodegradable substrates as fuel. The common microbial fuel cells consist of an anodic chamber and a cathode chamber separated by a proton exchange membrane. The microorganisms actively catabolize the substrate generating bioelectricity. These cells can be used as an energy generator for biosensors, giving this a great advantage for application in these types of devices. This paper presents microbial fuel lines, designed at low cost, in which the concentration of sludge has been varied, which was obtained from the oxidation lagoons of Covicorti, Trujillo-La Libertad. The values ​​of the average voltage were reduced as the concentration of the mud decreases, from values ​​close to 507.8 to 244.1 mV. The conductivity in the anodic chamber was around 14.5 to 7.75 μS / cm with a pH around 8.0. While in the cathodic carame a pH around 7.5 and a turbidity between 250 to 450 NTU was found, the values ​​of current intensity and power density also decrease with the reduction of residual sludge. With this work, it is about giving a new way of manufacturing CCM in an innovative and economical way. Recientemente, se ha puesto gran atención a las celdas de combustible microbianas (CCM) debido a sus condiciones de operación moderadas y al uso de una variedad de sustratos biodegradables como combustible. Las celdas de combustible microbianas comunes consisten en una cámara anódica y una cámara catódica separadas por una membrana de intercambio protónico. Los microorganismos catabolizan activamente el sustrato generando bioelectricidad. Estas celdas se pueden utilizar como un generador de energía para biosensores, dando con esto una gran ventaja para aplicación en estos tipos de dispositivos. En este trabajo se presenta cedas de combustible microbianas, diseñadas a bajo costo, en las cuales se ha variado la concentración de lodo, el cual fue obtenido de las lagunas de oxidación de Covicorti, Trujillo- La Libertad. Los valores del voltaje promedio fueron reduciendo a medida que disminuye la concentración del lodo, desde valores cercanos a 507.8 a 244.1 mV. La conductividad en la cámara anódica estuvo alrededor de 14,5 a 7,75 µS/cm con un pH alrededor de 8,0. Mientras que en la carama catódica se encontró un pH alrededor de 7,5 y una turbidez entre 250 a 450 UNT; los valores de la intensidad de corriente y densidad de potencia también disminuyen con la disminución de lodo residual. Con este trabajó se trata de dar una nueva forma de fabricación de CCM de manera innovadora y económica.

The hippocampal CA3 region plays a key role in learning and memory. Recurrent CA3–CA3 synapses are thought to be the subcellular substrate of pattern completion. However, the synaptic mechanisms of this network computation remain enigmatic. To investigate these mechanisms, we combined functional connectivity analysis with network modeling. Simultaneous recording from up to eight CA3 pyramidal neurons revealed that connectivity was sparse, spatially uniform, and highly enriched in disynaptic motifs (reciprocal, convergence, divergence, and chain motifs). Unitary connections were composed of one or two synaptic contacts, suggesting efficient use of postsynaptic space. Real-size modeling indicated that CA3 networks with sparse connectivity, disynaptic motifs, and single-contact connections robustly generated pattern completion. Thus, macro- and microconnectivity contribute to efficient memory storage and retrieval in hippocampal networks.