A numerical study of the ex-ROFI of the Colorado River

The freshwater discharge of the Colorado River into the Gulf of California has been reduced to negligible quantities since the construction of the Hoover Dam in 1935. These radical anthropogenic changes in the hydrography of the Colorado River Delta had striking repercussions on both physical and biological processes. Using historical river discharge data, the changes in the flow dynamics and hydrographic patterns before and after the drastic freshwater reduction are studied numerically, using a three-dimensional nonlinear shelf model. The results are applied to assess the environmental impact of the reduction of river discharge on the area. Satellite imagery is also used to compare our results with observed fronts

Spatio-Temporal Distribution of Deep Convection Observed along the Trans-Mexican Volcanic Belt

Complex terrain features - in particular, environmental conditions, high population density and potential socio-economic damage - make the Trans-Mexican Volcanic Belt (TMVB) of particular interest regarding the study of deep convection and related severe weather. In this research, 10 years of Moderate-Resolution Imaging Spectroradiometer (MODIS) cloud observations are combined with Climate Hazards Group Infrared Precipitation with Station (CHIRPS) rainfall data to characterize the spatio-temporal distribution of deep convective clouds (DCCs) and their relationship to extreme precipitation. From monthly distributions, wet and dry phases are identified for cloud fraction, deep convective cloud frequency and convective precipitation. For both DCC and extreme precipitation events, the highest frequencies align just over the higher elevations of the TMVB. A clear relationship between DCCs and terrain features, indicating the important role of orography in the development of convective systems, is noticed. For three sub-regions, the observed distributions of deep convective cloud and extreme precipitation events are assessed in more detail. Each sub-region exhibits different local conditions, including terrain features, and are known to be influenced differently by emerging moisture fluxes from the Gulf of Mexico and the Pacific Ocean. The observed distinct spatio-temporal variabilities provide the first insights into the physical processes that control the convective development in the study area. A signal of the midsummer drought in Mexico (i.e., “canícula”) is recognized using MODIS monthly mean cloud observations

Climatic analysis linked to land vegetation cover of Mexico by applying multivariate statistical and clustering analysis

"Se delimitan las regiones climáticas de México mediante el análisis jerárquico de agrupamiento. Los datos utilizados fueron medias mensuales de temperatura máxima y mínima y la precipitación mensual acumulada, obtenidas de estaciones climáticas en México para el periodo 1961-2004. Este método de agrupamiento asigna cada variable de precipitación y temperatura a grupos con base en características estadísticas similares. Se realizó un análisis de componentes principales para obtener una matriz estandarizada que se utilizó en el agrupamiento. Aplicando dos criterios de agrupamiento (K-means y Ward) fue posible definir estadísticamente los grupos de estaciones que delimitan regiones de clima similar. Además, la metodología empleada describe la distribución de la vegetación dominante para cada región climática. Este análisis puede contribuir a la generación de nuevos escenarios climáticos, donde puede incluirse la dinámica de la cobertura vegetal como bioindicador del clima.""The climate regions of Mexico are delimitated using hierarchical clustering analysis (HCA). The data used consists of monthly means of maximum and minimum temperatures and monthly-accumulated precipitation. The dataset was obtained from heterogeneously distributed climatic stations in Mexico for the period from 1961 to 2004. This cluster method assigns precipitation and temperature variables to groups of clusters based on similar statistical characteristics. We carried out a principal components analysis to obtain a standardized reduced matrix to be used in HCA. By applying two clustering criteria (K-means and Ward´s method) it was possible to define statistically groups of stations that delimit regions of similar climate. In addition, the applied methodology describes the dominant vegetation distribution for each climate region. This analysis may contribute to the generation of new climate scenarios, where the dynamics of land vegetation cover could be included as a biomarker of climate.

Hidrodinámica de un sistema arrecifal coralino en el oeste del Golfo de México

The acoustic Doppler current profiler, temperature, salinity and density data set were recorded monthly over the course of a year in a tropical coral reef system to elucidate the effects of abrupt bathymetric changes on current variability and surface temperature over time. A minimum of five transect repetitions were performed during one diurnal tidal cycle each month during the year 2008. According to the empirical orthogonal functions, the dominant terms were advection and friction due to the shallowness of the system and the relatively short continental shelf located in front of the Port of Veracruz (Mexico). The data showed the dominance of the northwest-southeast current velocity components (parallel to the coast) attributed to the winds. The southeastward current velocity was the dominant component throughout the year, followed by the northwestward current velocity component. The data suggested that coral reefs produce current rectification near the shallow reef areas (1 m depth). No correlation existed between surface temperature and the chlorophyll-a levels throughout the year. Residual current velocities throughout the year never reached more than 50 cm –1 during the sampling periods, and the surface temperature varied from 21 to 30°C, with the highest temperature being observed near the coast and reefs. Finally there was a direct correlation of the northeasterly and strong northwesterly winds with the well-mixed cold-salty water column in the reef area.Las corrientes marinas, la temperatura del agua, la salinidad y densidad del mar fueron registradas mensualmente a lo largo de un año, en un sistema de arrecifes coralinos del Golfo de México, para obtener los efectos de los cambios batimétricos sobre la variabilidad de las corrientes marinas y de la temperatura superficial. Se realizó un mínimo de cinco repeticiones, para cada transecto durante un ciclo de marea diurna, de forma mensual durante el 2008. De acuerdo con las Funciones Ortogonales Empíricas (EOF), los términos dominantes fueron la advección y la fricción. Esto se debió a la poca profundidad del sistema (< 45 m) y a la plataforma continental, relativamente corta, situada frente al puerto de Veracruz (México). Los datos mostraron que la componente de velocidad dominante en el sistema es paralela a la costa (sureste-noroeste) principalmente debido al régimen de vientos. La dirección de la velocidad de la corriente dominante fue hacia el sureste seguida por el componente noroeste. Los datos sugieren que los arrecifes de coral producen una rectificación de la corriente cerca de las zonas de arrecifes poco profundas (1 m de profundidad). No se encontró en este estudio una correlación entre la temperatura de la superficie y los niveles de clorofila-a lo largo del año. Las velocidades de las corriente residual a lo largo del año no rebasaron los 50 cm s–1 durante los períodos de muestreo, y la temperatura superficial variaron de 21 a 30°C. La temperatura más alta se observó cerca de la costa y los arrecifes. Por último, existe una correlación directa entre los vientos del noroeste con la columna de agua mezclada (fría y salada) en el área muestreada

Regionalization and classification of bioclimatic zones in the central-northeastern region of México using principal component analysis (PCA)

"Utilizando un análisis de componentes principales, determinamos zonas climáticas en un gradiente topográfico en la zona centro-noreste de México. Se emplearon datos de precipitación y temperatura medias mensuales por un período de 30 años de 173 estaciones meteorológicas. La clasificación del clima fue llevada a cabo de acuerdo con el sistema de Köppen modificado para las condiciones de México. El análisis de componentes principales indicó una regionalización que concuerda con características de topografía y vegetación. Se describen zonas bioclimáticas, asociadas a vegetación típica para cada clima, usando sistemas de información geográfica (SIG).""Applying principal component analysis (PCA), we determined climate zones in a topographic gradient in the central-northeastern part of México. We employed nearly 30 years of monthly temperature and precipitation data at 173 meteorological stations. The climate classification was carried out applying the Köppen system modified for the conditions of México. PCA indicates a regionalization in agreement with topographic characteristics and vegetation. We describe the different bioclimatic zones, associated with typical vegetation, for each climate using geographical information systems (GIS).

Lagrangian trajectories, residual currents and rectification process in the Northern Gulf of California

"Considering a semi-implicit approximation of the Coriolis terms, a numerical solution of the vertically integrated equations of motion is proposed. To test the two-dimensional numerical model, several experiments for the calculation of Euler, Stokes and Lagrange residual currents in the Gulf of California were carried out. To estimate the Lagrangian residual current, trajectories of particles were also simulated. The applied tidal constituents were M2, S2, K2, N2, K1, P1 and O1. At spring tides, strong tidal velocities occur in the northern half of the gulf. In this region of complex geometry, depths change from a few meter in the northern shelf zone to more than 3000 m in the southern part. In the archipelago region, the presence of islands alters amplitude and direction of tidal currents producing a rectification process which is reflected in a clockwise circulation around Tiburón Island in the Lagrangian residual current. The rectification process is explained by the superposition of the Euler and Stokes residual currents. Residual current patterns show several cyclonic and anticyclonic gyres in the Northern Gulf of California. Numerical experiments for individual and combinations of several tidal constituents revealed a large variability of Lagrangian trajectories.

Determinación de la eficiencia del proceso de lodos activados para la remoción de carga orgánica en las aguas residuales domesticas del sistema Imhoff en la provincia de Asunción-Ancash 2015

En esta tesis de investigación se evaluara la eficiencia del proceso de lodos activados para la remoción de carga orgánica expresados en demanda bioquímica de oxígenos y solidos suspendidos totales, aplicando tres concentraciones diferentes de lodos activos y tres tratamientos por cada uno (9 tratamientos), para las aguas residuales domesticas del sistema Imhoff en la provincia de Asunción-Distrito de Chacas-departamento de Ancash. El proceso de lodos activo tiene tres unidades o componentes principales, sedimentador primario, taque de aireación y sedimentador secundario. Una vez finalizado de construir la planta piloto de lodos activados se hicieron las pruebas de aireación, donde se midió el oxígeno disuelto durante 2. 5 horas, para evaluar si está o se asemeja a las condiciones necesarias para dicho tratamiento. Antes de empezar se sacó dos muestras iniciales de cada tratamiento para que estas sean llevadas al laboratorio en Lima, para sus respectivos análisis de DBO y STT, con la finalidad que estos resultados sean patrones de comparación al finalizar cada tratamiento. Al final de todo el tratamiento se obtuvo una eficiencia de remoción de carga orgánica expresados en demanda bioquímica de oxigeno (DBO) en un 53% y solidos suspendidos totales (SST) en un 92% con la concentración de lodos activos de 8.5 litros, llegando a estar dentro de los estándares de calidad ambientales de categoría III, así mismo cumpliendo con las recomendaciones de la norma de saneamiento OS 090

Estimation of total yearly CO2 emissions by wildfires in Mexico during the period 1999–2010

"The phenomenon of wildfires became a global environmental problem which demands estimations of their CO2 emissions. Wildfires have deteriorated the air quality increasingly. Using available information on documented wildfires and a data set of satellite detected hot spots, total yearly emissions of CO2 in Mexico were estimated for the period 1999-2010. A map of the main vegetation groups was used to calculate total areas for every vegetation type. The yearly number of hot spots per vegetation type was calculated. Estimates of emitted CO2 in a wildfire were then accomplished by considering parameters such as: forest fuel load, vegetation type, burning efficiency, and mean burned area. The number of wildfires and total affected areas showed an annual variability. The yearly mean of affected area by a single wildfire varied between 0.2 and 0.3 km(2). The total affected area during the period 1999 to 2010 was 86800 km(2) which corresponds to 4.3% of the Mexican territory. Total CO2 emissions were approximately 112 Tg. The most affected vegetation types were forest and rainforest.

Calidad en el sector de salud privado de lima metropolitana en el 2014

El presente trabajo de investigación se ha realizado con el propósito de identificar el nivel de cumplimiento de los factores de éxito de la Administración de la Calidad Total en las empresas del sector Salud Privado de Lima Metropolitana en el Perú en el año 2014. Para llevar a cabo el estudio se realizó una encuesta a un total de 247 clínicas del sector salud privado de Lima Metropolitana, delimitando este sector al conjunto de entidades que velan por el bienestar y prevención de la salud de las personas dentro de una población, sean estos centros de salud, policlínicos particulares, clínicas y consultorios privados. El resultado de la encuesta permitió obtener una muestra total de 70 entidades, con las cuales se procedió a tabular y realizar el análisis de los resultados. A nivel general, la calificación obtenida de los nueve factores de éxito de la Administración de la Calidad Total, fue de 3.71 dentro de una escala de Likert de 1 a 5, por el valor promedio obtenido se puede concluir que las empresas del sector de salud privado de Lima Metropolitana en el Perú al 2014, tienden a cumplir los factores de éxito de la Administración de la Calidad Total, sin embargo aún tienen oportunidad de realizar una mejor gestión para incrementar su desempeño en cada uno de los factores de éxito.The aim of the present study was to identify the level of compliance of the success factors of Total Quality Management applied in companies of the Lima Private Health Sector by 2014. In order to carry out the study, a survey was performed in 247 private health sectors, focusing on health centers, private clinics, clinics and private practices. The result of the survey yielded a total sample of 70 institutions that we proceeded to tabulate and analyze the results. Overall, the score obtained for the nine Total Quality Management success factors was 3.71 in Likert scale from 1 to 5. Due to the average value obtained, it can be concluded that the Lima-Peru Private Health Sector companies by 2014 met the success factors of Total Quality Management. However, they still have opportunity to improve their performance management of each of the success factors.Tesi