oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Patrón de transporte de sedimento en Bahía Magdalena, Baja California Sur, México, inferido del análisis de tendencias granulométricas
Sánchez,Alberto; Choumiline,Evgueni; Estela López-Ortiz,Blanca; Aguí?iga,Sergio; Sánchez-Vargas,Lilia; Romero-Guadarrama,Armando; Rodríguez-Meza,Durga;
Latin american journal of aquatic research , 2010,
Abstract: the grain-size trend analysis (grain size, sorting asymmetry) was determined at 58 stations in order to infer the residual vectors of sediment transport in magdalena bay, baja california sur, mexico. grain-size trend analysis and principal components analysis were applied to textural sediment parameters. the results indicated that well-sorted sediment is associated with fine to very fine sand. the residual vector transport suggests the presence of two gyres in the dispersion of clastic material: (1) acycloneic gyre in the deeper, central part and (2) an acycloneic gyre in the southeast part of the bay. the sediment transport pattern is highly correlated with the residual tidal currents in magdalena bay.
Patrón de transporte de sedimento en Bahía Magdalena, Baja California Sur, México, inferido del análisis de tendencias granulométricas Sediment transport patterns in Magdalena Bay, Baja California Sur, Mexico, inferred from grain-size trends
Alberto Sánchez,Evgueni Choumiline,Blanca Estela López-Ortiz,Sergio Aguí?iga
Latin american journal of aquatic research , 2010,
Abstract: Las tendencias espaciales de los parámetros texturales (tama o medio de grano, selección y asimetría) en Bahía Magdalena, Baja California Sur, México, se calcularon a partir de 58 estaciones de muestreo, con la finalidad de inferir la trayectoria de los vectores residuales de transporte de sedimentos. Los análisis de las tendencias espaciales y de componentes principales aplicados a los parámetros texturales indicaron que el sedimento, con una buena selección, está asociado con arenas finas a muy finas. Los vectores residuales de transporte sugieren la presencia de dos giros en la dispersión de material clástico: (1) giro ciclónico en la parte central y profunda, y (2) giro anticiclónico en la región sureste de la bahía. Las trayectorias de las partículas sedimentarias tienen una excelente correlación con las corrientes residuales de marea dentro de la Bahía Magdalena. The grain-size trend analysis (grain size, sorting asymmetry) was determined at 58 stations in order to infer the residual vectors of sediment transport in Magdalena Bay, Baja California Sur, Mexico. Grain-size trend analysis and principal components analysis were applied to textural sediment parameters. The results indicated that well-sorted sediment is associated with fine to very fine sand. The residual vector transport suggests the presence of two gyres in the dispersion of clastic material: (1) acycloneic gyre in the deeper, central part and (2) an acycloneic gyre in the southeast part of the bay. The sediment transport pattern is highly correlated with the residual tidal currents in Magdalena Bay.
Primer registro de Eumops perotis (Chiroptera: Molossidae) en la Peninísula de Baja California
Martínez-Gallardo, R;Guevara-Carrizales, AA;Couoh-de la Garza, R;Flores-Rojas, Ε;
Universidad y ciencia , 2008,
Abstract: one specimen of eumpos perotis was collected at sierra de juarez, baja california, mexico. this record represents the first one of this species for the state and for the baja california peninsula.
Subsidence of the Laguna Salada Basin, northeastern Baja California, Mexico, inferred from Milankovitch climatic changes  [PDF]
Juan Contreras,Arturo Martín-Barajas,Juan Carlos Herguera
Geofísica internacional , 2005,
Abstract: Laguna Salada in northern Baja California, Mexico, is an active half-graben product of the trans-tensional tectonics of the Gulf of California. It is sensitive to changes in sediment supply from the Colorado River basin. We present a time series analysis of the upper 980 m of a gamma-ray log from a borehole drilled near the Laguna Salada fault. The power spectrum of the gamma-ray log resembles the spectrum of δ18O Pleistocene isotopic variations from ice cores and from the deep ocean, known to be strongly controlled by Milankovitch cycles. We correlate δ18O stages with silty and sandy intervals in the log. Downcore ages for the last 780 ky are constrained within ~10 kyr. We derive a simple time vs. depth calibration relation for the basin over this time interval. Estimated sedimentation rates at the drill site appear to be constant with a value of ~1.6 mm/yr. We propose that this subsidence rate is produced by the Laguna Salada fault.
Primer registro de una colonia de Leptonycteris curasoae (Chiroptera: Phyllostomidae) en Baja California, México
Guevara-Carrizales, Aldo A.;Martínez-Gallardo, Roberto;Moreno-Valdez, Arnulfo;
Revista mexicana de biodiversidad , 2010,
Abstract: we report the first record of a colony of the phillostomid bat leptonycteris curasoae for baja california, mexico. this region represents the second locality reported for this species in the state.
Estimación de Factores de Emisión de PM10 y PM2.5, en Vías Urbanas en Mexicali, Baja California, México
Meza,Lourdes M; Quintero,Margarito; García,Rafael; Ramírez,Jorge;
Información tecnológica , 2010, DOI: 10.4067/S0718-07642010000400007
Abstract: the objective of this research was to estimate the emission factors (ef) for evaluating the amount of particulate matter from paved and unpaved roads in the city of mexicali, baja california, mexico. the model used was ap-42 of the u.s. epa, under a random statistical design, corresponding to 60 sampling sites in a georeferenced map utm 11 north projection. load values were obtained and percent of sediment less than 75 μm in the laboratory, speed and number of vehicles in the field. the estimated fe correspond to 0.92 kg pm10/vkt and 0.73 kg pm2.5 / vkt on paved road and 2.33 kg pm10/vkt and 0.58 kg pm2.5 / vkt on unpaved roads, respectively. the value of fe determines the amount of particulate matter to be suspended and the relation of the emission factors (pm10 and pm2.5) in both roadways indicate that maintenance and control of vehicle flux may be needed.
Aprendizaje en microempresas de Baja California
Texis Flores, Michelle;Mungaray Lagarda, Alejandro;Ramírez Urquidy, Martín;Ramírez Angulo, Natanael;
Estudios fronterizos , 2011,
Abstract: mexico's business structure has been characterized by the presence of microenterprises, particularly those averaging two workers, representing 65% of establishments in 2008 and 18% of employment. this makes them important for equity and welfare improvement of their members. this paper analyzes the performance of a group of 227 microenterprises in the state of baja california, by the use of a practical application of the concept of learning curve arranged to incorporate returns to scale. the results indicate that in 48% of cases there is evidence of learning processes and 58% exhibited increasing returns to scale. this allows evaluating the development potential of these microenterprises and the design and implementation of proactive programs that encourage their learning and consolidation in the market.
Primer registro de una colonia de Leptonycteris curasoae (Chiroptera: Phyllostomidae) en Baja California, México First record of a Leptonycteris curasoae (Chiroptera: Phyllostomidae) colony in Baja California, Mexico
Aldo A. Guevara-Carrizales,Roberto Martínez-Gallardo,Arnulfo Moreno-Valdez
Revista mexicana de biodiversidad , 2010,
Abstract: En el presente trabajo se registra por primera vez una colonia del murciélago filostomido Leptonycteris curasoae para Baja California, México, que también constituye la segunda localidad en el estado donde se registra esta especie. We report the first record of a colony of the phillostomid bat Leptonycteris curasoae for Baja California, Mexico. This region represents the second locality reported for this species in the state.
A new Ambrosia (Asteraceae) from the Baja California Peninsula, Mexico
León de la Luz, José Luis;Rebman, Jon P.;
Boletín de la Sociedad Botánica de México , 2010,
Abstract: ambrosia humi león de la luz et rebman, sp. nov., a member of the franseria alliance, is here described and illustrated. this taxon is apparently endemic only to mesa de humí in the sierra de la giganta of baja california sur, mexico. this new species is a subshrub with three-parted leaves that are gently scented and viscid when fresh, and it has a bur-like pistillate head, at maturity it is densely covered with strong, sharp, aculeate spines.
Bioclimatología de la Coccidioidomicosis en Baja California, México
Baptista-Rosas, Raúl C.;Arellano, Evarista;Hinojosa, Alejandro;Riquelme, Meritxell;
Investigaciones geográficas , 2010,
Abstract: the bioclimatic study of coccidioidomicosis, an endemic disease of the arid lands of america, caused by the ascomycetes coccidioides spp., is related to two aspects: the well known spatial distribution of the disease associated to desert environments, and the correlation between the incidence of cases and meteorological events. in northern mexico, the impact and spatial distribution of the disease are practically unexplored. in this work we analyzed the probable endemic area in baja california based on bioclimatic variables and using geographic information systems (gis). the relation between meteorological events and the reported cases of the disease was analyzed during the period of january 1988 to december 1994. a correlation between the number of reported cases for the disease, the accumulated monthly pluvial precipitation (pp) and the high and low average temperatures was found. existing evidence proposes that the endemic region of baja california has a bimodal rain pattern, in summer and winter, which is characteristic of bioclimatic transition zones. the reported cases of the disease were registered mainly in the driest months of the year after seasonal rains. it is considered that in the most southern region of baja california the most favorable bioclimatic conditions for the habitat of coccidioides spp. are met; in the transition zone of mediterranean-desert biomas.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.