Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

En el presente trabajo se ha calculado la sección eficaz de la producción de bosones de Higgs neutros , mediante la colisión del par electrón-positrón, teniendo en cuenta la corrección provocada por el “beamstrahlung” (BS) y la radiación del estado inicial.  Se presenta un panorama del Modelo 3-3-1 con leptones pesados basado en el grupo SU(3)L U(1)N. La adición de leptones pesados cargados extiende los dobletes del Modelo estándar (ME) a tripletes, mientras que en el sector de Higgs se introducen tres tripletes, a diferencia del MS que incluye un solo doblete. Las nuevas partículas introducidas en este modelo adquieren masa mediante el mecanismo de Higgs. El sector más desarrollado es el sector de Higgs con más partículas extendidas como: ,  , , , , ,  Las teorías que se utilizaron fueron los referentes: al Modelo 3-3-1, la cinemática relativista de altas energías, los diagramas de Feynman, los efectos correctivos de radiación Beamstrahlung y de estado inicial. El presente trabajo considera factores que intervienen en toda colisión de haces de partículas de alta energía, que no contribuyen a mejorar esta probabilidad de colisión como el Beamstrahlung y la radiación de Estado inicial. Para el cálculo numérico se utilizó un programa en Fortran.

La presente investigación tuvo como objetivo conocer los beneficios y desventajas ocasionados por la implementación de un sistema de Planeación de Recursos Empresariales (ERP) en la Universidad Nacional de Trujillo (UNT), Perú. La Universidad Nacional de Trujillo, siendo la primera universidad republicana del Perú, que forma profesionales y académicos competitivos, con calidad, críticos, éticos y socialmente responsables; a mediano plazo tendrá la necesidad de centralizar su información en una sola base de datos para conseguir optimizar sus servicios académicos y administrativos; frente a esta necesidad, la universidad necesitó conocer los beneficios y desventajas con la implementación de un sistema de Planeación de Recursos Empresariales. La metodología que se usó para identificar los beneficios y desventajas ocasionados por la implementación y post implementación de los Sistemas de Planificación de Recursos Empresariales, giraron en torno a la utilización de tres componentes primarios: La Revisión bibliográfica (Se analizan y sintetizan conceptos relacionados con sistemas Planeación de Recursos Empresariales en una organización, Cultura Organizacional e Impacto Organizacional);  Identificación de los macroprocesos de la Universidad Nacional de Trujillo (Según el Plan Bicentenario de la Universidad Nacional de Trujillo 2012-2024). Y finalmente se llegó a conocer o determinar los beneficios y desventajas ocasionados por la implementación de un sistema de Planeación de Recursos Empresariales en la Universidad Nacional de Trujillo. Las principales conclusiones a las que se llegó con el presente estudio fueron: la implementación de un sistema Planeación de Recursos Empresariales en una organización causa beneficios (aumento de calidad de servicio, mejor gestión de recursos, innovaciones, reducción de costos, empoderamiento, entre otros) y desventajas (alto de costo de adquisición, así como tiempo y complejidad de implementación) por lo tanto estos sistemas merecen un análisis minucioso y profesional a fin de obtener el máximo beneficios de ellos. Se destaca un beneficio sumamente importante que se logra con la implementación de un sistema de Planeación de Recursos Empresariales en una organización, es la adquisición de conocimientos por parte de los Recursos Humanos que puedan ser adiestrados en la operatividad de un sistema de Planeación de Recursos Empresariales en una organización.

El presente trabajo sustentado en el enfoque comunicativo, propone usar el collage y los caligramas como estrategia de aprendizaje que beneficia el equilibrio emocional para producir diferentes tipos de textos a fin de desarrollar habilidades escritas y virtuales usando las TIC en  inglés en la IE 80820 “Víctor Larco”, Trujillo. Tomando como base la investigación científica los estudiantes crearon textos en el idioma inglés en cada fecha cívica del calendario escolar a la vez que lo utilizaron como un recurso didáctico para mejorar su conocimiento gramatical, de vocabulario y cultural del inglés, desarrollar su creatividad, expresar sus emociones y reducir principalmente el ambiente de violencia y agresividad en las aulas. El diseño aplicado fue experimental, con una población de 53 estudiantes del 5to grado de educación secundaria y con una muestra de 37 estudiantes. Se elaboró un diseño de investigación en el que se complementaron las metodologías cualitativa y cuantitativa a fin de contrastar los resultados utilizando las técnicas de investigación propuestas. Los resultados obtenidos confirmaron la hipótesis presentada al existir una diferencia significativa entre los dos grupos evaluados. Por lo que se concluye que las estrategias aplicadas permitieron la producción de textos en inglés.

The Southeast Pacific Subtropical Anticyclone (SPSA) extends over the entire South Pacific Basin and it is the dominant forcing of the Humboldt Current System. The SPSA has seasonal, interannual, and decadal (interdecadal) variability. The latter variability has been associated with the Pacific Decadal Oscillation (PDO), recognized as a Pan-Pacific mode. However, most of the ocean–atmosphere studies on interdecadal scales have been conducted in the Northern Hemisphere, and very few in the Southern Hemisphere. Thus, through reanalysis model outputs and satellite data, this research mainly establishes the relationship between SPSA and PDO in the period 1949–2012 and its impact on sea surface temperature along the north-central coast of Chile between 2000 and 2012. For this purpose we first analyzed the seasonal and interannual variability of the SPSA. An analysis of correlation between air pressure at sea level and the PDO and Southern Annular Mode (SAM) indices established that, at the interdecadal scale, these oscillations explained 49% and 40% of the variance, respectively; however, SAM had a time lag of six years to explain this variance. The PDO, in the air pressure field, produced similar changes to El Niño–Southern Oscillation. Over the past 13 years, the SPSA has intensified and shifted toward the southwest, increasing the offshore Ekman transport and Ekman suction, which would explain much of the observed coastal cooling south of 33º S (central Chile). 

The effect of shrimp aquaculture effluents on some environmental parameters of the receiving coastal waters was assessed. Water and sediment samples were taken at different distances from the discharge point (50, 150, and 300 m) when shrimp farms had ceased operations (survey 1), had initiated operations (survey 2), and during the early harvest (survey 3). Water and sediment samples were likewise taken at the same distances from the shore in a non-impacted area. During surveys 1 and 2, the effluents had a negative effect at all three distances (50, 150, and 300 m) on the water quality variables (transparency, seston [total suspended solids, total inorganic solids, particulate organic matter], chlorophyll a, N-NO2–, N-NO3–, N-NH4+), on the sediment quality parameters (organic nitrogen), and on the TRIX index. Contrarily, no differences were observed when the impacted and non-impacted areas were compared during survey 3, probably because the effluents had diminished due to the premature harvesting. The results suggest that at the end of the farming period, the nutrient and organic matter load exceeded the assimilation capacity of the ecosystem, whereas during the recess period, the environment was capable of assimilating the excess organic matter accumulated. The levels reached by the monitored parameters did not exceed the limits established and the impact on the ecosystem is not severe, but they could represent a risk factor in the long term. Additionally, there is evidence that the temporary suspension of shrimp farming operations is beneficial for the environment. 

The agricultural drainage water from the Sinaloa valley (Mexico) is often reused in agriculture and aquaculture before reaching coastal water bodies. Discharged water must be of good quality to maintain the health of ecosystems and prevent damage to the organisms that compose them. This research determined the occurrence of coliforms in a drainage ditch known as La Michoacana (Sinaloa) that receives contaminated water from agricultural and urban sources. A section of 3.6 km was studied during 2013 and samples were obtained monthly from five equidistant sampling sites. Each water sample was analyzed for total coliform (TC) and fecal coliform (FC) content, pH, salinity, temperature, and dissolved oxygen percentage (%DO). The sampling sites with the highest bacterial contamination were associated with direct discharges of domestic wastewater and those with the lowest to the output drain. The performance of this agricultural ditch decreased the concentration of coliforms, with median and average values of 96% and 87% for TC, and 98% and 85% for FC, respectively. The most common bacteria were Escherichia coli (67.7%), Kluyvera cryocrescens (10.2%), and Enterobacter agglomerans (6.3%). Coliform concentration was positively correlated with temperature and negatively with %DO. The ditch improved the microbiological quality of the water, demonstrating remediation activities in the system. Proper management and maintenance of agricultural drainage ditches would favorably impact the health and biodiversity, as well as the intensive aquaculture and agricultural activities of the Sinaloa valley.

Given their biological characteristics, sharks exhibit low resilience and thereby are considered a fishery resource particularly vulnerable to overfishing. Yet, for several decades, three shark species (Sphyrna lewini, Rhizoprionodon longurio, and Carcharhinus falciformis) have contributed consistently to the catches of the artisanal shark fishery at the entrance to the Gulf of California, showing a certain degree of resilience. The aim of this study was to estimate their capacity to recover from disturbances, based on their rebound potential (r2M), and analyze the factors that may be favoring their capacity to recover from fishing pressure in the region. Catch records, size composition of landings reported in previous studies and from undertaken surveys, as well as published information on life history parameters were used in the present analysis. Rhizoprionodon longurio showed high productivity (r2M = 0.083) and thus high resilience, whereas C. falciformis and S. lewini presented medium productivities (r2M = 0.053 and 0.062, respectively), but alternative scenarios to consider uncertainty in the life history parameters of C. falciformis and S. lewini placed them in the low productivity category. All species presented low productivity when the more conservative natural mortality (e.g., 1.25M) to achieve maximum sustainable yield was considered. Catches were dominated by juveniles of S. lewini, and by preadults and adults of R. longurio and C. falciformis during all the analyzed period; this and their consistent contribution to landings suggest apparent population stability. Such stability might be related to their biological productivity, elasticity, wide distribution range, migratory habits, and size segregation. Nonetheless, changes that occurred in this fishery over the last three decades may have also played an important role in the catch levels, particularly in the case of C. falciformis. Quantitative population assessments of these species to determine the optimum levels of extraction in the region are urgently needed. 

Reproducible and reliable genetic transformation methods are a key tool for understanding the physiology and cell biology of Symbiodinium. Nevertheless, transformation methods previously applied to cells such as microalgae, including those utilizing glass beads, have not been tested on these microorganisms. Here, we report a simple, transient transformation method, which allowed plasmid incorporation into three distinct clades of cultured Symbiodinium cells with the plant-targeted plasmid pCB302 harboring sequences encoding a fusion of green fluorescent protein (gfp) with RACK1C from Arabidopsis thaliana (AtRACK1C). Accessibility of the plasmid to the resistant cell wall and through the plasma membrane of the dinoflagellates was achieved through vigorous shaking in the presence of glass beads and polyethylene glycol. A resistance gene to the herbicide Basta allowed appropriate selection in the photosynthetic cells. The transformation frequency per every 106 cells was 107 ± 7 transformants for Symbiodinium kawagutii, 74 ± 8 for Symbiodinium microadriaticum ssp. microadriaticum, and 65 ± 5 for Symbiodinium sp. Mf11. Moreover, Symbiodinium pulchrorum cultures were successfully transformed with a different vector (pCAMBIA-FABD2-gfp) under the same conditions, further validating our procedure. The observation of green fluorescent emission from the cell cytoplasm in all performed transformations indicated that the procedure allowed the heterologous plasmids to enter and undergo expression in the Symbiodinium cells. The success of this transient transformation method opens interesting possibilities for functional genomics studies in Symbiodinium spp. 

Urías Estuary, a coastal lagoon in northwestern Mexico, is impacted by multiple anthropogenic stressors. Its hydrodynamics (and consequent contaminant dispersion) is mainly controlled by tidal currents. To better manage the coastal lagoon, accurate tidal-level forecasting is needed. Here we compare the predictions of sea level rise simulated by a conventional harmonic analysis, through Fourier spectral analysis, and by nonlinear autoregressive models based on artificial neural networks, both calibrated and validated using field data. Results showed that nonlinear autoregressive networks are useful to simulate the sea level over a time scale of several days (<10 days), in comparison to harmonic analysis, which can be used for longer time scales (>10 days). We concluded that the joint use of both methods may lead to a more robust strategy to forecast the sea level in the coastal lagoon. 

The effect of hydroperiod on the survival and growth of Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle seedlings under experimental conditions was investigated using a simulated tidal system. Seedlings of the three mangrove species were grown at four inundation levels. All levels were flooded every 12 h in order to create a simulated semi-diurnal tide cycle (i.e., two high tides and two low tides per day). Based on the hydroperiod for the study area, level 1 was flooded for 10 h, level 2 for 6 h, level 3 for 2 h, and level 4 for 6 min. After 570 days, the results showed that R. mangle presented the highest growth at level 1 and the lowest growth at level 4. The optimal growth of L. racemosa occurred at levels 2 and 3, but all the seedlings died at level 1, indicating that this species is highly sensitive to tidal regimes. Compared to L. racemosa and R. mangle, A. germinans had a moderate growth rate at all four levels. Mangrove growth differentiations were more prominent at levels 1 and 3, where the three species showed very different growth patterns. Studies of optimal growth using hydroperiod experiments are important in order to understand the physiological responses of mangrove forests to a possible sea level rise in the next decades, especially in subtropical environments where they are constantly exposed to stress.