Potential GDP growth in Venezuela : a structural time series approach

Real GDP and oil prices are decomposed into common stochastic trend and cycle processes using structural time series models. Potential real GDP is represented by the level of the trend component of real GDP. The potential rate of growth of real GDP is represented by the stochastic drift element of the trend component. Cuevas finds that there is a strong association at the trend and cycle frequencies between real GDP and the real price of oil. This association is also robust in the presence of key economic policy variables. From 1970-80, when the underlying annual rate of increase of the real price of oil was 12 percent, the underlying annual rate of increase of potential GDP in Venezuela was 2.6 percent. By contrast, from 1981-2000 when the underlying rate of increase of the real price of oil was -5 percent, the underlying growth rate of potential GDP fell 1.5 percent. However, the strength of association between the underlying growth of oil prices and real GDP has fallen considerably since the early 1980s, suggesting that oil cannot be relied on as an engine for future growth in Venezuela.Environmental Economics&Policies,Climate Change,Poverty Impact Evaluation,Economic Theory&Research,Poverty Reduction Strategies,Economic Theory&Research,Environmental Economics&Policies,Energy Demand,Oil Refining&Gas Industry,Climate Change

Demand for imports in Venezuela : a structural time series approach

Using structural time series models, Cuevas estimates common stochastic trends of real GDP and imports in Venezuela from 1974-2000. The real imports trend drifts upward at almost twice the rate of growth of GDP. This highlights the powerful structural tendency toward increasing imports in Venezuela. The author also explicitly estimates common stochastic cycles, which he finds to have 5 and 17 year periods. In addition, he finds that a 1 percent real exchange rate appreciation leads to a 0.4 percent increase in imports. And in the long-run, 1 percent real GDP growth is associated with 1.7 percent real imports growth. The author also shows that the GDP elasticity of imports uniformly falls with cycle period, with the elasticity reaching 4.55 at the frequency associated with the 5-year cycle. A powerful imports responsiveness at the higher cycle frequency is associated with the recurrence of external imbalances in Venezuela.Environmental Economics&Policies,Climate Change,Consumption,Economic Theory&Research,Water Conservation,Economic Theory&Research,Environmental Economics&Policies,Macroeconomic Management,Economic Stabilization,Consumption

Efecto de la descarga de lodo y el tiempo de retención hidráulica en la remoción de sólidos suspendidos en un reactor UASB (reactor anaeróbico de flujo ascendente y manto de lodos)

La remoción de Sólidos Suspendidos Totales y Volátiles (SST y SSV) es un parámetro clave para determinar la eficiencia de un reactor UASB (Reactor Anaeróbico de Flujo Ascendente y Manto de Lodos). La remoción de SST y SSV está relacionada con el Tiempo de Retención Hidráulica (TRH) y la altura total de lodo bacteriano en el reactor. El crecimiento bacteriano es constante en los reactores biológicos y se hace necesario realizar descargas periódicas del exceso de lodo. En este trabajo se presentan los resultados obtenidos en un reactor UASB a escala piloto utilizado para el tratamiento de líquidos cloacales pre-sedimentados en la ciudad de Salta, Argentina. La extracción de lodo anaeróbico no afectó de manera significativa la calidad del efluente. La eficiencia del tratamiento (remoción de SST y SSV) se mantuvo por encima del 80% siempre que la altura de lodo remanente fue mayor de 1 m. El TRH óptimo fue de 6 h. La eficiencia de remoción de SST y SSV podría ser un criterio operativo para decidir la frecuencia de purgado en reactores UASB a escala real.The removal of Total and Volatile Suspended Solids (TSS & VSS, respectively), is a key parameter to assess the performance of UASB (Upflow Anaerobic Sludge Bed) reactors. TSS and VSS removal is associated with the Hidraulic Retention Time (HRT) and the amount of anaerobic sludge in the reactor. Bacterial growth is constant in biological reactors and periodic discharges of excess sludge have to be performed. In this work, results obtained in a pilot-scale UASB reactor treating pre-settled sewage from the city of Salta, Argentina, are presented. Excess sludge discharges did not affect significantly the quality of the effluent. Treatment efficiency (as TSS and VSS removal) was greater than 80% as long as the sludge height in the reactor was higher than 1 m. The optimum HRT was 6 h. TSS and VSS removal efficiency could be an operational criterion to decide the frequency for excess sludge discharges in full-scale UASB reactors.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Comprensión conceptual de electromagnetismo en el laboratorio mediante aprendizaje basado en problemas (ABP): Compreensão conceitual do eletromagnetismo no laboratório através do aprendizado baseado em problemas (PBL)

Los conceptos de electromagnetismo representan un reto para el aprendiz debido al grado de abstracción que tiene que desarrollar para entenderlos y aplicarlos, en este trabajo se muestra el resultado de un esfuerzo realizado durante el curso de laboratorio de electromagnetismo  para auxiliar al alumnado de pregrado en este proceso de abstracción y al mismo tiempo contribuir al desarrollo de habilidades blandas mediante el uso del Aprendizaje Basado en Proyectos (ABP) complementariamente con métodos tradicionales de enseñanza. Se compararon dos grupos uno donde se usó el método ABP y otro de control, al inicio y al final se aplica la misma evaluación conceptual de electricidad y magnetismo para observar si hubo diferencia en el grado de comprensión conceptual de la materia. Se utilizó el método de diferencia en diferencias para medir el impacto, los resultados no fueron alentadores, sin embargo, la mejoría de un 10% en el promedio motivaron a realizar un análisis de los resultados por temas; encontrando deficiencias en cálculo vectorial y en la aplicación conceptual de las leyes de Newton mostrando que la dificultad de abstracción conceptual por parte de los alumnos no solo es en electromagnetismo. Se observó cualitativamente que durante el proceso y la evaluación de los proyectos los alumnos mostraron habilidades blandas: trabajo en equipo, capacidad analítica y de discusión en resolución de problemas, trabajo interdisciplinario y gestión del trabajo

Efecto de la descarga de lodo y el tiempo de retención hidráulica en la remoción de sólidos suspendidos en un reactor UASB (reactor anaeróbico de flujo ascendente y manto de lodos)

La remoción de Sólidos Suspendidos Totales y Volátiles (SST y SSV) es un parámetro clave para determinar la eficiencia de un reactor UASB (Reactor Anaeróbico de Flujo Ascendente y Manto de Lodos). La remoción de SST y SSV está relacionada con el Tiempo de Retención Hidráulica (TRH) y la altura total de lodo bacteriano en el reactor. El crecimiento bacteriano es constante en los reactores biológicos y se hace necesario realizar descargas periódicas del exceso de lodo. En este trabajo se presentan los resultados obtenidos en un reactor UASB a escala piloto utilizado para el tratamiento de líquidos cloacales pre-sedimentados en la ciudad de Salta, Argentina. La extracción de lodo anaeróbico no afectó de manera significativa la calidad del efluente. La eficiencia del tratamiento (remoción de SST y SSV) se mantuvo por encima del 80% siempre que la altura de lodo remanente fue mayor de 1 m. El TRH óptimo fue de 6 h. La eficiencia de remoción de SST y SSV podría ser un criterio operativo para decidir la frecuencia de purgado en reactores UASB a escala real.The removal of Total and Volatile Suspended Solids (TSS & VSS, respectively), is a key parameter to assess the performance of UASB (Upflow Anaerobic Sludge Bed) reactors. TSS and VSS removal is associated with the Hidraulic Retention Time (HRT) and the amount of anaerobic sludge in the reactor. Bacterial growth is constant in biological reactors and periodic discharges of excess sludge have to be performed. In this work, results obtained in a pilot-scale UASB reactor treating pre-settled sewage from the city of Salta, Argentina, are presented. Excess sludge discharges did not affect significantly the quality of the effluent. Treatment efficiency (as TSS and VSS removal) was greater than 80% as long as the sludge height in the reactor was higher than 1 m. The optimum HRT was 6 h. TSS and VSS removal efficiency could be an operational criterion to decide the frequency for excess sludge discharges in full-scale UASB reactors.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Efecto de la descarga de lodo y el tiempo de retención hidráulica en la remoción de sólidos suspendidos en un reactor UASB (reactor anaeróbico de flujo ascendente y manto de lodos)

La remoción de Sólidos Suspendidos Totales y Volátiles (SST y SSV) es un parámetro clave para determinar la eficiencia de un reactor UASB (Reactor Anaeróbico de Flujo Ascendente y Manto de Lodos). La remoción de SST y SSV está relacionada con el Tiempo de Retención Hidráulica (TRH) y la altura total de lodo bacteriano en el reactor. El crecimiento bacteriano es constante en los reactores biológicos y se hace necesario realizar descargas periódicas del exceso de lodo. En este trabajo se presentan los resultados obtenidos en un reactor UASB a escala piloto utilizado para el tratamiento de líquidos cloacales pre-sedimentados en la ciudad de Salta, Argentina. La extracción de lodo anaeróbico no afectó de manera significativa la calidad del efluente. La eficiencia del tratamiento (remoción de SST y SSV) se mantuvo por encima del 80% siempre que la altura de lodo remanente fue mayor de 1 m. El TRH óptimo fue de 6 h. La eficiencia de remoción de SST y SSV podría ser un criterio operativo para decidir la frecuencia de purgado en reactores UASB a escala real.The removal of Total and Volatile Suspended Solids (TSS & VSS, respectively), is a key parameter to assess the performance of UASB (Upflow Anaerobic Sludge Bed) reactors. TSS and VSS removal is associated with the Hidraulic Retention Time (HRT) and the amount of anaerobic sludge in the reactor. Bacterial growth is constant in biological reactors and periodic discharges of excess sludge have to be performed. In this work, results obtained in a pilot-scale UASB reactor treating pre-settled sewage from the city of Salta, Argentina, are presented. Excess sludge discharges did not affect significantly the quality of the effluent. Treatment efficiency (as TSS and VSS removal) was greater than 80% as long as the sludge height in the reactor was higher than 1 m. The optimum HRT was 6 h. TSS and VSS removal efficiency could be an operational criterion to decide the frequency for excess sludge discharges in full-scale UASB reactors.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Physical and functional interaction between the dopamine transporter and the synaptic vesicle protein synaptogyrin-3.

Uptake through the dopamine transporter (DAT) represents the primary mechanism used to terminate dopaminergic transmission in brain. Although it is well known that dopamine (DA) taken up by the transporter is used to replenish synaptic vesicle stores for subsequent release, the molecular details of this mechanism are not completely understood. Here, we identified the synaptic vesicle protein synaptogyrin-3 as a DAT interacting protein using the split ubiquitin system. This interaction was confirmed through coimmunoprecipitation experiments using heterologous cell lines and mouse brain. DAT and synaptogyrin-3 colocalized at presynaptic terminals from mouse striatum. Using fluorescence resonance energy transfer microscopy, we show that both proteins interact in live neurons. Pull-down assays with GST (glutathione S-transferase) proteins revealed that the cytoplasmic N termini of both DAT and synaptogyrin-3 are sufficient for this interaction. Furthermore, the N terminus of DAT is capable of binding purified synaptic vesicles from brain tissue. Functional assays revealed that synaptogyrin-3 expression correlated with DAT activity in PC12 and MN9D cells, but not in the non-neuronal HEK-293 cells. These changes were not attributed to changes in transporter cell surface levels or to direct effect of the protein-protein interaction. Instead, the synaptogyrin-3 effect on DAT activity was abolished in the presence of the vesicular monoamine transporter-2 (VMAT2) inhibitor reserpine, suggesting a dependence on the vesicular DA storage system. Finally, we provide evidence for a biochemical complex involving DAT, synaptogyrin-3, and VMAT2. Collectively, our data identify a novel interaction between DAT and synaptogyrin-3 and suggest a physical and functional link between DAT and the vesicular DA system

Co-occurrence, possible origin, and health-risk assessment of arsenic and fluoride in drinking water sources in Mexico: Geographical data visualization

Arsenic and fluoride in drinking water present a significant challenge to public health worldwide. In this study, we analyze the results of one of the largest surveys of drinking water quality in Mexico: 14,058 samples from 3951 sites, collected between January and December 2017. We use these data to identify the distribution and possible origin of arsenic and fluoride in drinking water throughout the country, and to estimate the associated health burden. The highest concentrations appear in alluvial aquifers in arid northern Mexico, where high-silica volcanic rock likely releases both arsenic and fluoride to the groundwater. We find fluoride contamination to be significantly correlated with aridity (Pearson correlation = −0.45, p = 0.0105), and also find a significant difference in fluoride concentrations between arid and humid states (Welch's t-test, p = 0.004). We estimate population exposure by assigning to each town in Mexico the average concentration of any sampling sites within 5 km. Our results show that 56% of the Mexican population lives within 5 km of a sampling site, 3.05 million people are exposed to fluoride above the reference dosage of 0.06 mg/(kg ∗ day), 8.81 million people are exposed to arsenic above the limit of 10 μg/L, and an additional 13,070 lifetime cases of cancer are expected from this arsenic exposure alone. This burden of disease is concentrated in the arid states of north-central Mexico