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Sample records for baja california mexico

  1. Traditional medicine of Baja California Sur (Mexico). I.

    Science.gov (United States)

    Dimayuga, R E; Agundez, J

    1986-08-01

    This study deals with the medicinal use of 30 plants collected in the Municipio de Los Cabos and part of the Municipio de la Paz, Baja California Sur, Mexico. The plants were all taxonomically identified at least to genus level, and their medicinal use, as described to us by elder people, is discussed.

  2. Traditional medicine of Baja California Sur (Mexico). II.

    Science.gov (United States)

    Encarnacion Dimayuga, R; Fort Murillo, R; Luis Pantoja, M

    1987-08-01

    Continuing our studies of traditional medicine, as used in rural areas of Baja California Sur, now we wish to report on the medicinal uses of 49 more plants. Some of the more complex recipes of these medicinal plants, are discussed in the present paper. The information presented here was collected in the Municipio of Los Cabos and part of the Municipio of La Paz, B.C.S., Mexico.

  3. Virtues of simple hydro-economic optimization: Baja California, Mexico.

    Science.gov (United States)

    Medellín-Azuara, J; Mendoza-Espinosa, L G; Lund, J R; Harou, J J; Howitt, R E

    2009-08-01

    This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions.

  4. Microfossils from Cerro Prieto geothermal wells, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, M.L.; Haar, S.V.

    1982-08-10

    To aid in a paleonenvironmental and age reconstruction of the Cerro Prieto reservoir system, 59 samples of well cuttings were analyzed for microfossils. The cuttings were obtained at depths from 351 to 3495m in 14 geothermal wells in the Cerro Prieto field, Baja California, Mexico. Foraminifera was found in 6 samples, ostracodes in 19 samples and mannoplankton as coccoliths in 24 samples. Other groups, such as molluscus, insects, fish skeletal parts, and plant material were occasionally present. Detailed interpretations at this time cannot be made because of poor preservation of samples. This is primarily due to causes: dissolution by geothermal fluids that reach 350/sup 0/C, and the extensive mixing of filled Cretaceous forms (reworked from the Colorado Plateau region) with Tertiary species during drilling. Further studies of ostracodes and foraminifera from colder portions of the wells are needed. The abundant and well-preserved ostracodes indicate marine to backish water inviroments that correspond in part, to lagoonal or estuarine facies. The presence of the mid-Tertiary (15-m.y.-old) marine foraminifera, Cassigerinela chipolensis, in wells M-11 and M-38, 350 to 500m deep, is perplexing. These are not laboratory contaminates and, as yet have not been found in the drilling mud. If further studies confirm their presence at Cerro Prieto, established ideas about the opening of the Gulf of California and about Pacific Coast mid-Tertiary history will need to be rewritten.

  5. Microfossils from Cerro Prieto geothermal wells, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, M.L.; Vonder Haar, S.

    1980-01-01

    To aid in a paleoenvironmental and age reconstruction of the Cerro Prieto reservoir system, 59 samples of well cuttings were analyzed for microfossils. The cuttings were obtained at depths from 351 to 3495 m in 14 geothermal wells in the Cerro Prieto field, Baja California, Mexico. We found foraminifera in 6 samples, ostracodes in 19 samples, and nannoplankton as coccoliths in 24 samples. Other groups, such as molluscs, insects, fish skeletal parts, and plant material were occasionally present. Detailed interpretations are not possible at this time because of poor preservation of samples. This is primarily due to causes: dissolution by geothermal fluids that reach 350{sup 0}C, and the extensive mixing of filled Cretaceous forms (reworked from the Colorado Plateau region) with Tertiary species during drilling. Further studies of ostracodes and foraminifera from colder portions of the wells are needed. The abundant and well-preserved ostracodes indicate marine to brackish water environments that correspond, in part, to lagoonal or estuarine facies. The presence of the mid-Tertiary (15-My-old) marine foraminifera, Cassigerinela chipolensis, in wells M-11 and M-38, 350 to 500 m deep, is perplexing. These are not laboratory contaminates and, as yet, have not been found in the drilling mud. If further studies confirm their presence at Cerro Prieto, established ideas about the opening of the Gulf of California and about Pacific Coast mid-Tertiary history will need to be rewritten.

  6. The economic value chain of wine in Baja California, Mexico

    OpenAIRE

    2015-01-01

    Recent economic policy debates have centered on increasing and quantifying the value chain, and the objective of this research is to characterize the value chain of vitiviniculture in Baja California according to organizational subsystems, including management, marketing, quality, productivity and environment. This study presents a comparative analysis between the capabilities of the vitiviniculture industry and sectors within which it participates. The analysis shows that the primary issues ...

  7. Identifying recharge from tropical cyclonic storms, Baja California Sur, Mexico.

    Science.gov (United States)

    Eastoe, Christopher J; Hess, Greg; Mahieux, Susana

    2015-04-01

    Groundwater in the Todos Santos watershed in southern Baja California, and throughout the peninsula south of latitude 28°N, has values of (δ18 O‰, δD‰) ranging between (-8.3, -57) and (-10.9, -78). Such negative values are uncharacteristic of the site latitude near the sea level. Altitude effects do not explain the isotope data. Tropical depressions originating along the Pacific coast of North America yield rain with isotopic depletion; rain from these weather systems in southern Arizona commonly has δ18O values50 mm) at least once every 2 to 3 years, and along the Pacific coast between Jalisco and Oaxaca.

  8. The economic value chain of wine in Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Salvador González Andrade

    2015-07-01

    Full Text Available Recent economic policy debates have centered on increasing and quantifying the value chain, and the objective of this research is to characterize the value chain of vitiviniculture in Baja California according to organizational subsystems, including management, marketing, quality, productivity and environment. This study presents a comparative analysis between the capabilities of the vitiviniculture industry and sectors within which it participates. The analysis shows that the primary issues are related to sectors that have weak productive infrastructure, marketing problems, product shortages and few local suppliers, and additional problems include insufficient funding, water shortages and high taxes. Moreover, investments in human capital are required to train human resources.

  9. Health Care among the Kumiai Indians of Baja California, Mexico: Structural and Social Barriers

    Science.gov (United States)

    Fleuriet, K. Jill

    2009-01-01

    In this article, the author documents the illness and health care problems facing indigenous communities in Baja California, Mexico, by using ethnographic data from research she conducted from 1999 to 2001 with rural, indigenous Kumiai and with their primary health care providers in urban Ensenada. The author contends that barriers to care are…

  10. California sea lions (Zalophus californianus californianus) have lower chlorinated hydrocarbon contents in northern Baja California, Mexico, than in California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Del Toro, Ligeia [Universidad Autonoma de Baja California (UABC), Facultad de Ciencias Marinas, Ensenada, Baja California (Mexico); Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico); Heckel, Gisela [Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico) and Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C. Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico)]. E-mail: gheckel@cicese.mx; Camacho-Ibar, Victor F. [Instituto de Investigaciones Oceanologicas, UABC, Apdo. Postal 453, Ensenada, Baja California 22860 (Mexico); Schramm, Yolanda [Universidad Autonoma de Baja California (UABC), Facultad de Ciencias Marinas, Ensenada, Baja California (Mexico); Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico)

    2006-07-15

    Chlorinated hydrocarbons (CHs) were determined in blubber samples of 18 California sea lions (Zalophus californianus californianus) that stranded dead along Todos Santos Bay, Ensenada, Baja California, Mexico, January 2000-November 2001. {sigma}DDTs were the dominant group (geometric mean 3.8 {mu}g/g lipid weight), followed by polychlorinated biphenyls ({sigma}PCBs, 2.96 {mu}g/g), chlordanes (0.12 {mu}g/g) and hexachlorocyclohexanes (0.06 {mu}g/g). The {sigma}DDTs/{sigma}PCBs ratio was 1.3. We found CH levels more than one order of magnitude lower than those reported for California sea lion samples collected along the California coast, USA, during the same period as our study. This sharp north-south gradient suggests that Z. californianus stranded in Ensenada (most of them males) would probably have foraged during the summer near rookeries 500-1000 km south of Ensenada and the rest of the year migrate northwards, foraging along the Baja California peninsula, including Ensenada, and probably farther north. - Results suggest that sea lion prey must also have lower hydrocarbons in Baja California than in California in the USA.

  11. Islas Marias Archipelago, Mexico. A Missing Piece to Reconstruct the Paleoposition of Baja California

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    Schaaf, P. E.; Pompa, V.; Hernandez, T.; Weber, B.; Solis, G.; Villanueva, D.; Perez-Venzor, J.

    2011-12-01

    Paleopositions for southern Baja California peninsula have yielded controversial models over the past 30 years. Mainly based on paleomagnetic data many hypotheses place Baja at lower paleolatitudes in front of southern Mexico or Central America with subsequent northward translations. Other models suggest minor, if any, northward displacements with respect to continental Mexico combined with clockwise rotations. Lithological, geochemical, and geochronological similarities for southern Baja California and Puerto Vallarta (western Mexico Pacific margin) igneous rocks seem to confirm the latter model. To further prove this model we have mapped and collected rocks from Maria Madre, the largest island of the Islas Marias archipelago, located in the mouth of the Gulf of California. In an area of only 145 square kilometers, metamorphic basements rocks (ortho and migmatitic gneisses), highly deformed metasediments, granitoids, acid to intermediate volcanic sequences, and a cover with gently folded marine sediments are exposed. The basement complex with gneisses and metasediments, including garnet-bearing paragneiss and calc silicates, as well as the granodioritic-tonalitic intrusives display an extraordinary accordance with similar units observed in the Los Cabos Block (LCB) of Baja California Sur. Furthermore, U-Pb zircon ages of 162 and 170 Ma for the basement gneisses and of 80 Ma for the granitoids have been reported also from the LCB. Additionally, upper Cretaceous intrusive ages are well known from the Puerto Vallarta batholith in Jalisco and Nayarit, mainland Mexico. Geochemical and isotopic data as well as Nd model ages confirm a magmatic consanguinity of LCB, Islas Marias, and Puerto Vallarta granitoids. The volcanic units of Maria Madre Island include ignimbrites and effusive dacitic-rhyolithic rocks, which can be correlated to the Sierra Madre Occidental province and the Comundú Formation of Baja California. Age determinations are under work to confirm this

  12. Stratigraphy of Reforma Caldera, Baja California Sur, Mexico

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    García Sánchez, L.; Macias, J. L.; Osorio, L. S.; Pola, A.; Avellán, D. R.; Arce, J. L.; Saucedo, R.; Sánchez, J. M.; García-Tenorio, F.; Cisneros, G.; Reyes-Agustín, G.; Cardona, S.; Jimenez, A.

    2015-12-01

    The Reforma caldera is located at ~35 km to the northwest of Santa Rosalía in the central part of the Baja California peninsula. It has 10 km in diameter and a maximum height of 1200 masl in the center and between 100 and 500 masl in its slopes. Reforma is within a tectonic zone affected by two fault systems: A NW-SE normal fault system linked to the opening of the Gulf of California, and a NNW-SSE and NW-SE strike-slip fault system associated with an active Riedel system. Reforma was built upon Cretaceous granites that outcrop at the caldera center, Miocene to Pliocene volcano-sedimentary rocks of the Comondú group, and Miocene marine sediments of the Santa Rosalía basin. On top of these rocks outcrop at least four submarine to subaerial ignimbrites interbedded with marine fossiliferous beds and the lower Pleistocene deposits associated to the Reforma caldera. These deposits are formed by a ignimbrite that shifts to different lithofacies that change gradually their welding, here dubbed basal, transitional, intermediate, and upper (all of then enriched in black fiammes), followed by a pumice-rich, white fiammes, and vitrophyre lithofacies, which are distributed around the 9 km wide caldera and have been associated to the caldera formation episode. Deposits related to post-caldera volcanism are andesite-basaltic lava flows erupted along the caldera rim through localized feeding dikes and andesitic and rhyolitic domes, and scoria cinder cones exposed inside and outside the caldera. On top of these deposits rest the middle Pleistocene Aguajito caldera deposits.

  13. Assessing neuropsychological performance in a migrant farm working Colonia in Baja California, Mexico: a feasibility study.

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    Bousman, Chad A; Salgado, Hugo; Hendrix, Terence; Fraga, Miguel; Cherner, Mariana

    2011-08-01

    Neuropsychological impairments (NPI) can lead to difficulties in daily functioning and ultimately contribute to poor health outcomes. However, evidence for the feasibility of NPI assessment in resource-limited settings using tests developed in high literacy/high education cultures is sparse. The main objectives were to: (1) determine the feasibility and appropriateness of conducting neuropsychological assessments among a migrant farm worker population in Baja California, Mexico and (2) preliminary describe neuropsychological test performance in this unique population. A neuropsychological test battery was administered to 21 presumably healthy adults (8 men, 13 women) during a two-day international health services and research collaboration. All but one neuropsychological test (i.e. figure learning) was feasible and appropriate to administer to the study population. Contrary to expectations, participants performed better on verbal rather than nonverbal neuropsychological tests. Results support inclusion of neuropsychological tests into future studies among migrant farm worker populations in Baja California, Mexico.

  14. An annotated distributional checklist of exotic freshwater fishes from the Baja California Peninsula, Mexico

    OpenAIRE

    Gorgonio Ruiz-Campos; Salvador Contreras-Balderas; Asunción Andreu-Soler; Alejandro Varela-Romero; Ernesto Campos

    2012-01-01

    We documented the distributional status of 27 exotic fish species in the inland waters of the Baja California Peninsula, Mexico, based on voucher specimens collected from 122 sites between 1977 and 2010, and on published records. The species reported here are representatives of genera from the Atlantic drainages of North America (Ictalurus, Ameiurus, Pylodictis, Morone, Lepomis, Pomoxis, Dorosoma, Cyprinella, and Micropterus), Middle America (Poecilia, Gambusia, and Xiphophorus), Eurasia (Cyp...

  15. Heavy metals in the fine fraction of coastal sediments from Baja California (Mexico) and California (USA).

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    Villaescusa-Celaya, J A; Gutiérrez-Galindo, E A; Flores-Muñoz, G

    2000-06-01

    The concentrations of heavy metals in the fine fraction (Mexico) and California (USA) were determined. The concentration ranges (in microg g(-1)) of the metals were: Cu, 4.9-23; Zn, 39-188; Ni, 16-44; Cr, 56-802; Pb, 6-21; Cd, 0.08-0.64; Ag, 0.01-0.28; and Mn, 392-1506; the intervals (percentage) for Fe and Al were 1.36-4.6 and 3.61-8.55, respectively. The heavy metals in these sediments indicate a relative enrichment of Cr (>3000%), Zn (>350%), Ni (>300%) and Cu (>150%) off the wastewater outfall at Punta Bandera in Tijuana, Baja California, with respect to non-polluted sediments of the region. Pb, Cd and Ag have low concentrations off the same outfall and enrichment factors are generally lower than 300% (Pb) and lower than 150% (Cd and Ag). This suggests that these metals have a different origin, or that they are controlled by a different geochemical mechanism than the former. The concentrations of Mn, Fe and Al occurred within ranges typical for coastal areas and probably reflect the mineralogical composition of the sediments of the region.

  16. Susceptibility of pepper weevil (anthonomus eugenii cano) (coleoptera: curculionidae) to seven insecticides in rural areas of Baja California Sur, Mexico

    OpenAIRE

    Rosalía Servín Villegas; José. L. García Hernández; Armando Tejas Romero; José L. Martínez Carrillo; M. A. Toapanta

    2008-01-01

    The susceptibility of the pepper weevil (Anthonomus eugenii), collected from Baja California Sur, Mexico, to seven insecticides was determined. Acontact, residual exposition method was used to obtain the lethal concentrations fifty (LC50) and the diagnostic concentration (LC95) of organophosphates (OF), carbamates (CA), pyrethroids (PIR), and organochlorine (OC) insecticides used to control pepper weevils from two agricultural areas (Los Planes and Todos Santos) in Southern Baja California Pe...

  17. Agave turneri (Agavaceae), a new species from northeastern Baja California, Mexico

    Science.gov (United States)

    Webb, Robert H.; Salazar-Ceseña, J. Mario

    2011-01-01

    Agave turneri, a new species of Agave from the Sierras Cucapá and El Mayor in northeastern Baja California, Mexico, is a medium-sized species that does not produce offsets, has a relatively short and narrow panicle, and has a distinctive flower structure. The closest relatives to this new species are Agave moranii, which occurs approximately 200 km to the south of the type locality, and A. deserti var. simplex, which occurs in Arizona and California. This new species is a narrow endemic restricted to specific granodiorite and tonalite habitats in a hyperarid environment. Agave turneri appears to be a critically endangered owing to its habitat preference for specific types of granite in the Sierra Cucapá, threats due to prolonged drought and global change, and its close proximity to the Mexicali metropolitan area.

  18. Numerical understanding of regional scale water table behavior in the Guadalupe Valley aquifer, Baja California, Mexico

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    J. R. Campos-Gaytan

    2006-05-01

    Full Text Available A regional groundwater flow model was developed, in order to evaluate the water table behavior in the region of the Guadalupe Valley, in Baja California, Mexico. The State of Baja California has been subject to an increment of the agricultural, urban and industrials activities, implicating a growing water-demand. However, the State is characterized by its semi-arid climate with low surface water availability; resulting in an extensive use of groundwater in local aquifer. Based on historic piezometric information of the last two decades, however, a negative evolution could be observed, resulting a negative storage volume. So far, there is not an integral hydrogeological evaluation that determine the real condition of the groundwater resource, and that permit to planning a management of the Guadalupe Valley Aquifer. A steady-state calibration model was carried out in order to obtain the best possible match to measured levels at the Guadalupe Valley Aquifer. The contours of calculated water table elevations for January 1983 were reproduced. Generally, the comparison of the observed and calculated water table configurations have a good qualitative and quantitatively adjustment. Nowadays, it is count with a hydrogeological model that can be used for simulates the groundwater flow in the region of the Guadalupe Valley.

  19. Preliminary geologic studies of Sierra El Aguajito (Baja California, Mexico): a resurgent-type caldera

    Science.gov (United States)

    Garduño-Monroy, V. H.; Vargas-Ledezma, H.; Campos-Enriquez, J. O.

    1993-12-01

    Geologic field studies conducted in the Quaternary volcanic field of Tres Virgenes (State of Baja California Sur, Mexico) revealed the existence of a resurgent caldera. The caldera's eruptive products, the Aguajito sequence, overlie the products of the nearby Reforma caldera (Reforma sequence) whose youngest products have already been dated as Quaternary. The rim of the Aguajito caldera is inferred by the existence of an arcuate alignment of rhyolitic domes. The mean diameter of this subcircular feature is 10 km. The volume of its mapped acidic products is a minimum of 10 km 3. Several horizons within the sequence contain shells. K/Ar dates of the ignimbrites and domes of El Aguajito formation confirm that the unit are Pleistocene. The detailed stratigraphy also shows the evolution of a marine regression partly related to the caldera.

  20. Management by results in Mexico, 2013-2014. Some effects in Baja California

    Directory of Open Access Journals (Sweden)

    José María Ramos García

    2016-07-01

    Full Text Available This paper examines the results-based management (RBM proposal promoted by the Mexican federal government and how this proposal has been applied. This article presents the theory of management according to its results and its effects on competitiveness and well-being. This article analyzes the conceptual elements of the model and the manners in which this model has been instituted both conceptually and operationally in Brazil, Mexico, and the Mexican state of Baja California. Principal findings include the need to strengthen institutional capacities for RBM to enhance competitiveness and well-being at the government level, internalize a vision of strategic change, and prioritize cultural change to generate efficient transparency, accountability and anti-corruption controls by a transversal focus based on the elements of management.

  1. SELF-POTENTIAL SURVEY AT THE CERRO PRIETO GEOTHERMAL FIELD, BAJA CALIFORNIA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, R.F.; Diaz C., S.; Rodriguez B., J.

    1978-06-01

    In December 1977, two self-potential survey lines were run across the producing area of the Cerro Prieto geothermal field, located about 30 km south of Mexicali, Baja California, Mexico. The purpose of the survey was to determine whether significant self-potential variations were related to the known geothermal activity. Large-amplitude, long-wavelength self-potential anomalies are seen in the Cerro Prieto geothermal field. The inflection points of the anomalies are roughly centered over two major faults thought to act as conduits for the thermal fluids, and the form of the anomalies indicates that they may be generated by electrical activity extending to a depth of several km along the fault zones. Thus, self-potential measurements may be helpful in tracing thermally active fault zones in the Cerro Prieto area.

  2. Developing a Luminescence Chronology for Fan-terrace Sediments, Los Cabos, Baja California, Mexico

    Science.gov (United States)

    Rhodes, E. J.; Brown, N. D.; Antinao, J.; Huenupi, E. C.; Baker, S. E.; McDonald, E.

    2012-12-01

    Extensive depositional units forming large terrace units within alluvial fans close to the southern tip of Baja California, Mexico, record sedimentation under a very different climatic regime from the present. Dating these sediments presents significant challenges; they contain very sparse organic material suitable for radiocarbon dating; their upper surfaces are heavily bioturbated, in some places eroded and in other locations show signs of continued deposition even after incision and base level fall, rendering them difficult to date using TCN (terrestrial cosmogenic nuclide) methods. Locations that have experienced significant regional tectonic influences associated with rapid erosion (e.g. Transverse Ranges, California, Southern Alps, New Zealand, Himalaya and Tibet) are typically not well-suited for quartz OSL (optically stimulated luminescence) application owing to low signal sensitivity. For this reason, our efforts to develop a chronology for the sandy sediments that characterize these contexts have focussed on IRSL dating of K-feldspar, using newly developed post-infrared IRSL (infra-red stimulated luminescence) approaches. We explore the relative advantages of different techniques, and methods to assess both the degree of incomplete zeroing and signal fading. In particular, we explore how novel single grain IRSL measurements of K-feldspar can be applied to these and similar high energy deposits on timescales ranging from the last 100,000 years to a few decades. Based on our chronology coupled with detailed sedimentological and soil stratigraphy investigations, we are able to exploit these deposits as valuable archives of past environmental and climatic change.

  3. Geochemistry of igneous rocks from the Cerro Prieto geothermal field, northern Baja California, Mexico

    Science.gov (United States)

    Herzig, C. T.

    1990-08-01

    Fractional crystallization of basaltic magma, derived from an oceanic affinity source region present beneath the Salton Trough and emplaced into a pull-apart basin of this continental rift regime, produced a tholeiitic suite of hypabyssal rocks consisting of basalt, andesite and dacite within the Cerro Prieto geothermal field, located in northern Baja California, Mexico. Higher light-rare-earth-element abundances for a basalt from the Cerro Prieto geothermal field in comparison to basalts from the Gulf of California and the East Pacific Rise suggest partial assimilation of crustal materials into the parental magmas generated beneath the Salton Trough. The crustal contaminant may be present near the surface today in the form of granitoids of the Peninsular Ranges batholith, at deeper levels as hydrothermally altered materials near the base of the Salton Trough, or may be a relict feature of Tertiary subduction contained within the upper mantle beneath the Salton Trough. The Sr isotopic compositions of dacites from the nearby Cerro Prieto volcano range from 0.7029 to 0.7036, indicating an oceanic affinity source for these rocks. The suite of hypabyssal rocks of tholeiitic affinity present within the Cerro Prieto geothermal field, related by fractional crystallization, link the dacite volcano of Cerro Prieto to gabbroic plutons inferred to exist beneath the Cerro Prieto geothermal field.

  4. Subsidence and Extension Rates of Laguna Salada Basin, Northeastern Baja California, Mexico

    Science.gov (United States)

    Contreras, J.; Martin-Barajas, A.; Herguera, J. C.

    2002-12-01

    Laguna Salada basin in northeastern Baja California, Mexico, is an active half-graben product of the trans-tensional tectonics of the Gulf of California. It lies at the boundary between the North America and Pacific plates, 15 km west of the Cerro Prieto-Imperial fault system. We present the results of a time series analysis of the uppermost 980 m of a gamma ray log from the geothermal exploratory well ELS1 drilled in the proximity of the Laguna Salada fault, which bounds the basin on its eastern margin. Our analysis indicates its stratigraphy is cyclical and that the spectrum of the gamma ray log is similar to the spectrum of δ18O Pleistocene variations, which strongly suggest an orbital origin. Based on this, we establish a correlation between the gamma ray log and δ18O stages to constrain ages of sediments with an estimated uncertainty of ~10 kyr. We found that sedimentation rates at ELS1 site have remained constant during the last 780 kyr. The sedimentation rate at the ELS1 site is 1.6 mm/yr. This value is extrapolated to obtain the vertical and perpendicular to strike slip rates of Laguna Salada fault. It was found that the vertical slip component is 4.22 mm/yr and the perpendicular to strike slip component (E-W direction) is 1.55 mm/yr.

  5. Degree of trace metal pyritization in sediments from the Pacific coast of Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Nava Lopez, Carmen; Huerta Diaz, Miguel Angel [Instituto de Investigaciones Oceanologicas, Ensenada, Baja California (Mexico)

    2001-06-01

    We analyzed sediments from a core collected on the Pacific coast of Baja California, 45 km off the city of Tijuana and at 1257 m water depth (32 Celsius degrees 9.5N , 117 Celsius degrees 8.3W), for trace metal content in two operationally-defined fractions, HCl and pyrite. Our results indicate transference of Cu>Ni>Zn>>Hg y Ag from the HCl to the pyrite fraction. Sediments have degrees of pyritization (DOP) that average 7.2{+-} 4.9% with a maximum value of 18.5%. Average degrees of trace metal pyritization (DTMP) range from 6.2 {+-}2.1% to 83{+-} 8% for Mn and Hg, respectively, although maximum values for some metals were closed to 100%. This transference is apparently a function of the solubility products of metal sulfides and the relative abundances of metals in the HCl fraction, as suggested by the significant correlation (p<0.001) observed between these two parameters and the DTMP of a number of trace metals. A similar correlation was obtained from published data of two cores collected in the Gulf of Mexico. [Spanish] Se analizaron sedimentos de un nucleo recolectado en la costa del Pacifico de Baja California 45 km de la costa de la ciudad de Tijuana y a 1257 m de profundidad del agua (32 grados Celsius 9.5N, 117 grados Celsius 8.3W), para determinar su contenido de metales traza en dos fracciones operacionales definidas HCl y pirita. Los resultados indican una transferencia de Cu>Ni>Zn>>Hg y Ag de la fraccion de HCl a la fase piritica. Los grados de piritizacion (DOP) en los sedimentos promediaron 7.2{+-} 4.9%, con un valor maximo de 18.5%. Los valores promedio de los grados de piritizacion de metales traza (DTMP) abarcaron el intervalo de 6.2 {+-}2.1% a 83{+-}18% para Mn y Hg, respectivamente, aunque los valores maximos para algunos metales estuvieron cercanos al 100%. Esta transferencia aparentemente es funcion de los productos de solubilidad de los sulfuros metalicos y de la abundancia relativa de metales en la fraccion HCl, como sugiere la correlacion

  6. Petrology and Geochronology of High-Grade Metamorphic Rocks from Cedros Island, Baja California, Mexico

    Science.gov (United States)

    Gonzales, D.; Leech, M. L.

    2014-12-01

    High-grade metamorphic rocks exposed on Cedros Island, Baja California, Mexico, record the Mesozoic subduction history of western North America. Blocks of amphibolite, blueschist, and eclogite crop out in a serpentinite-matrix mélange on the southeast and southwestern parts of Cedros Island. Amphibolite blocks contain Amp + Ep + Ab + Chl ± Ms ± Grt ± Ttn ± Qz; blueschist blocks have the assemblage Na-Amp + Ms + Lw + Qz ± Ttn ± Grt ± Jd ± Chl; and eclogite blocks are comprised primarily of Omp + Grt with retrograde Na-Amp + Ms + Lw. Blueschists from Cedros have been dated using 40Ar/39Ar step-heating of white mica and sodic amphiboles that yield ages from 103 ± 4 Ma to 94.9 ± 1.1 Ma, respectively, that represent cooling during exhumation. Apatite fission-track dating gives ages from 32 ± 4 Ma to 22 ± 3 Ma that record exhumation through the upper crust. Related Mesozoic subduction zone rocks of the Franciscan Complex crop out in a serpentinite-matrix mélange along coastal northern California. The Franciscan rocks are older, yielding 40Ar/39Ar step-heating ages of hornblende from amphibolite ranging from 159 to 156 Ma and represent an older part of the subduction history of the oceanic Farallon plate along western North America. I will determine the prograde and peak metamorphic P-T conditions for these high-grade rocks using petrography, mineral chemistries, and isochemical phase diagram modeling with Perple_X to generate complete P-T paths. I will then supplement these data with Sm-Nd and Lu-Hf geochronology for these high-grade Cedros rocks to evaluate their subduction/exhumation history, and develop a tectonic model for these southernmost Franciscan-type rocks. Ultimately, I will compare my results to Franciscan rocks in northern California to better understand the Mesozoic subduction margin of western North America.

  7. en Baja California

    Directory of Open Access Journals (Sweden)

    Elmyra Ybañez Zepeda

    2007-01-01

    Full Text Available In the future, the population of 60 years old or older will increase in absolute and relative numbers at a very rapid pace in Mexico. Using data from Censo general de población y vivienda 2000, Encuesta sobre migración en la frontera norte de México and Consejo Nacional de Población (Conapo, the purpose of this article is twofold: first of all, to analyze the aging process in the municipalities of Tijuana and Mexicali, located in the state of Baja California, which has a very low proportion of the eldest; and second of all, to examine the role of migration in this process. Tijuana has a younger population which is aging slowly due to a very intense immigration of young workers and potential parents. Mexicali, on the other hand, has a high percentage of a native population that is aging unrelentingly, and it also has a lower flow of immigrants who are older, and includes a high concentration of persons who had previously resided in the United States.

  8. AUTOCHTHONOUS BIOFACIES IN THE PLIOCENE LORETO BASIN, BAJA CALIFORNIA SUR, MEXICO

    Directory of Open Access Journals (Sweden)

    MICHELE PIAZZA

    1998-07-01

    Full Text Available The present paper examines the molluscan and/or echinoid assemblages recovered from two lithostratigraphic units (Piedras Rodadas Sandstone and Arroyo de Arce Norte Sandstone outcropping in the Pliocene Loreto Basin, Baja California Sur, Mexico. Ten biofacies have been identified, i.e. Trachycardium procerum-Trachycardium senticosum Biofacies, Chione compta-Transennella modesta Biofacies, Laevicardium elenense-Chione kelletii Biofacies, Xenophora sp. 1-Strombus subgracilior Biofacies, Crassostrea californica osunai Biofacies, Myrakeena angelica Biofacies, Vermetid-Nodipecten Biofacies, Argopecten abietis abietis Biofacies, Aequipecten dallasi Biofacies and Encope Biofacies. The first four biofacies have been defined on the basis of statistical analyses (cluster analysis, MDS. The other six, which are monospecific or definitely low-diversity, were already identified during field work. The deduced paleoecological bearing of biofacies, largely relying upon the comparison to their closest modern counterparts, provides the basis for the paleoenvironmental reconstruction. The latter also considers sedimentological evidence and is framed within the tectonic and sedimentary context recently proposed by American workers. Biofacies point toward environments differing in terms of substrate texture, presence/absence of vegetal cover, energy level, variously distributed within the low tide mark-40 m bathymetric range. 

  9. Subsidence of the Laguna Salada Basin, northeastern Baja California, Mexico, inferred from Milankovitch climatic changes

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Juan; Martin-Barajas, Arturo [Departamento de Geologia, CICESE, Ensenada Baja California (Mexico); Herguera, Juan Carlos [Division de Oceanologia, CICESE, Ensenada Baja California (Mexico)

    2005-01-15

    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 gammaray log resembles the spectrum of {delta}{sup 1}8{omicron} Pleistocene isotopic variations from ice cores and from the deep ocean, known to be strongly controlled by Milankovitch cycles. We correlate {delta}{sup 1}8{omicron} stages with silty and sandy intervals in the log. Downcore ages for the last 780 ky are constrained within {approx}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 {approx}1.6 mm/yr. We propose that this subsidence rate is produced by the Laguna Salada fault. [Spanish] La cuenca de Laguna Salada en el norte de Baja California, Mexico, es un semigraben activo producto de la tectonica ranstensional del Golfo de California. Esta cuenca endorreica es sensible a cambios en sedimentacion por variaciones en el aporte e sedimentos de fuentes cercanas y distales transportados por arroyos de las sierras adyacentes y por el Rio Colorado. Esta cuenca es un sitio excepcional para explorar el uso de cambios climaticos ciclicos como herramienta de datacion y estimar tasas de sedimentacion y subsidencia en el area. Para demostrar esto se presenta un analisis de series de tiempo de un registro de rayos de gama de un pozo geotermico exploratorio perforado adyacente a la falla de Laguna Salada, la cual limita el margen oriental de la cuenca. Los resultados del analisis indican que el espectro de los primeros 980 m del registro de rayos gama tiene una alta coherencia con el espectro de registros isotopicos paleoclimaticos de {delta}{sup 1}8{omicron} del

  10. Late Pleistocene-Holocene alluvial stratigraphy of southern Baja California, Mexico

    Science.gov (United States)

    Antinao, José Luis; McDonald, Eric; Rhodes, Edward J.; Brown, Nathan; Barrera, Wendy; Gosse, John C.; Zimmermann, Susan

    2016-08-01

    A late Pleistocene to Holocene alluvial stratigraphy has been established for the basins of La Paz and San José del Cabo, in the southern tip of the Baja California peninsula, Mexico. Six discrete alluvial units (Qt1 through Qt6) were differentiated across the region using a combination of geomorphologic mapping, sedimentological analysis, and soil development. These criteria were supported using radiocarbon, optically stimulated luminescence and cosmogenic depth-profile geochronology. Major aggradation started shortly after ∼70 ka (Qt2), and buildup of the main depositional units ended at ∼10 ka (Qt4). After deposition of Qt4, increasing regional incision of older units and the progressive development of a channelized alluvial landscape coincide with deposition of Qt5 and Qt6 units in a second, incisional phase. All units consist of multiple 1-3 m thick alluvial packages deposited as upper-flow stage beds that represent individual storms. Main aggradational units (Qt2-Qt4) occurred across broad (>2 km) channels in the form of sheetflood deposition while incisional stage deposits are confined to channels of ∼0.5-2 km width. Continuous deposition inside the thicker (>10 m) pre-Qt5 units is demonstrated by closely spaced dates in vertical profiles. In a few places, disconformities between these major units are nevertheless evident and indicated by partly eroded buried soils. The described units feature sedimentological traits similar to historical deposits formed by large tropical cyclone events, but also include characteristics of upper-regime flow sedimentation not shown by historical sediments, like long (>10 m) wavelength antidunes and transverse ribs. We interpret the whole sequence as indicating discrete periods during the late Pleistocene and Holocene when climatic conditions allowed larger and more frequent tropical cyclone events than those observed historically. These discrete periods are associated with times when insolation at the tropics was

  11. New geologic slip rates for the Agua Blanca Fault, northern Baja California, Mexico

    Science.gov (United States)

    Gold, P. O.; Behr, W. M.; Fletcher, J. M.; Hinojosa-Corona, A.; Rockwell, T. K.

    2015-12-01

    Within the southern San Andreas transform plate boundary system, relatively little is known regarding active faulting in northern Baja California, Mexico, or offshore along the Inner Continental Borderland. The inner offshore system appears to be fed from the south by the Agua Blanca Fault (ABF), which strikes northwest across the Peninsular Ranges of northern Baja California. Therefore, the geologic slip rate for the ABF also provides a minimum slip rate estimate for the offshore system, which is connected to the north to faults in the Los Angeles region. Previous studies along the ABF determined slip rates of ~4-6 mm/yr (~10% of relative plate motion). However, these rates relied on imprecise age estimates and offset geomorphic features of a type that require these rates to be interpreted as minima, allowing for the possibility that the slip rate for the ABF may be greater. Although seismically quiescent, the surface trace of the ABF clearly reflects Holocene activity, and given its connectivity with the offshore fault system, more quantitative slip rates for the ABF are needed to better understand earthquake hazard for both US and Mexican coastal populations. Using newly acquired airborne LiDAR, we have mapped primary and secondary fault strands along the segmented western 70 km of the ABF. Minimal development has left the geomorphic record of surface slip remarkably well preserved, and we have identified abundant evidence meter to km scale right-lateral displacement, including new Late Quaternary slip rate sites. We verified potential reconstructions at each site during summer 2015 fieldwork, and selected an initial group of three high potential slip rate sites for detailed mapping and geochronologic analyses. Offset landforms, including fluvial terrace risers, alluvial fans, and incised channel fill deposits, record displacements of ~5-80 m, and based on minimal soil development, none appear older than early Holocene. To quantitatively constrain landform ages

  12. Macroalgas submareales de la bahía de Todos Santos, Baja California, México Submareal macroalgae of the Todos Santos Bay, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Raúl Aguilar-Rosas

    2010-12-01

    Full Text Available Con el fin de identificar y caracterizar la composición de especies de la zona submareal de la bahía de Todos Santos, Baja California, México; se realizaron muestreos de macroalgas marinas bentónicas en 7 sitios durante 1995-2000. Como resultado de 25 buceos Scuba entre 3 y 33 m de profundidad se encontraron 150 especies de macroalgas para el área de estudio; 10 son Chlorophyta, 26 Phaeophyta y 114 Rhodophyta. Del total, 47 son registros nuevos para el área de estudio y 2 de éstos, Faucheocolax attenuata Setchell y Minium parvum R.L. Moe, son nuevos para la flora marina del Pacífico de México. Se incluye una revisión de las investigaciones en las que se han considerado las macroalgas presentes en la bahía de Todos Santos y una discusión sobre la composición de las especies encontradas, su distribución vertical y reproducción, así como sobre las especies epífitas y parásitas del área.In order to identify and characterize the species composition of the subtidal zone of the Todos Santos Bay, Baja California, Mexico, benthic marine macroalgae were sampled at 7 sites from 1995 to 2000. As a result of 25 scuba at derds for the study area, of which Faucheocolax attenuata Setchell and R.L Moe Minium parvum are new to the marine flora of Pacific Mexico. We include a research that consider the macroalpths between 3 and 33 m we found a total of 150 species of macroalgae for the study area, of which 10 are Chlorophyta, 26 Phaeophyta and 114 Rhodophyta; 47 species represent new recogae in the Todos Santos Bay and a discussion on the composition of species found, its vertical distribution and reproduction, particularly the species epiphytes and parasites present in the study area.

  13. Reconnaissance geologic map of the Loreto and part of the San Janier quadrangles, Baja California Sur, Mexico

    Science.gov (United States)

    McLean, Hugh

    1988-01-01

    The Loreto area of Baja California Sur, Mexico, contains a diverse association of igneous, sedimentary, and metasedimentary rocks exposed in the foothills and arroyos between the Sierra La Giganta and Gulf of California. The Loreto area was selected for this study to examine the possible relation of the marine rocks to the opening of the Gulf of California, and to determine the stratigraphic and structural relations between basement rocks composed of granitic and prebatholithic rocks and overlying Tertiary (mainly Miocene) sedimentary and volcanic rocks, and by a sequence of Pliocene marine and nonmarine sedimentary rocks. The Pliocene marine rocks lie in a structural depression informally called here, the Loreto embayment. This geologic map and report stem from a cooperative agreement between the U.S. Geological Survey and the Consejo de Recursos Minerales of Mexico that was initiated in 1982.

  14. Stratigraphy and geochronology of the Comondú Group near Loreto, Baja California sur, Mexico

    Science.gov (United States)

    Umhoefer, Paul J.; Dorsey, Rebecca J.; Willsey, Shawn; Mayer, Larry; Renne, Paul

    2001-10-01

    Upper Oligocene to Middle Miocene volcanic and sedimentary rocks in the Loreto region, Baja California Sur, are widely exposed and make up the Comondú Group as redefined here following McFall. The Comondú Group is part of a volcanic arc and forearc basin that formed along the northwestern margin of Mexico. Regional to detailed scale mapping, stratigraphic analysis, and geochronology in a 10-20-km-wide and 70-km-long belt from the gulf escarpment to the coast near Loreto reveal three main units in the Comondú Group and a composite thickness of ˜1.5-2 km. (1) The lower clastic unit (˜30-19 Ma) contains 200-300 m of fluvial sandstone and conglomerate with probable local eolian deposits and numerous felsic tuffs and basalt flows that accumulated in a forearc basin. (2) The middle breccia and lava flow unit (˜19-15 Ma) is up to 750 m thick and consists of massive andesite breccia that was deposited as proximal debris flows interbedded with minor andesite lava flows. (3) The upper lava flow and breccia unit (˜15-12 Ma) consists almost entirely of up to ˜600 meters of andesite lava flows a few kilometers west of Loreto that are part of a composite volcano. North and south of Loreto for up to 25 km, the unit is composed of andesite lava flows and massive andesite breccia that formed from thick debris flows near that and other volcanic centers. The three units of the Comondú Group in the Loreto area correlated with the Salto, Pelones, and Ricasón formations of the Bahı´a Concepción area. The lower clastic unit of this study is time equivalent to the marine San Gregorio, El Cien, and Isidro formations on the western and southern Baja California peninsula. The middle and upper units of the Loreto area are the proximal equivalent to the type section of the Comondú Group near the village of Comondú. During deposition of the lower part of the Comondú Group, the arc lay to the east on mainland Mexico in the Sierra Madre Occidental, and then migrated to the

  15. Heavy metals in geochemical sediment fractions of the border region between Baja California, Mexico, and California, USA; Metales pesados en fracciones geoquimicas de sedimentos de la region fronteriza de Baja California, Mexico, y California, EUA

    Energy Technology Data Exchange (ETDEWEB)

    Villaescusa-Celaya, Julio A; Gutierrez-Galindo, Efrain A; Flores-Munoz, Gilberto [Instituto de Investigaciones Oceanologicas, Universidad Autonoma de Baja California, Ensenada, B.C., (Mexico)

    1997-03-01

    The concentrations of the heavy metals Cu, Zn, Ni, Cr, Pb, Cd, Ag, Mn and Fe in the different geochemical sediment fractions are determined in this study, as a means of assessing the impact of residual wastewater on the coastal sediments of the region. During an oceanographic cruise in April 1992 (ECOBAC IV), 20 samples of surface sediments were collected from the coastal shelf of the border region between Baja California (Mexico) and California (USA), The sediment samples were subjected to a sequential extraction procedure designed to obtain the geochemical fractions defined as: exchangeable (F1), carbonates (F2), Fe and Mn oxyhydroxides (F3), organic matter/sulfides (F4) and residual or lithogenic (F5). The operational speciation of the metals indicates that the principal phases in the sediments that accumulate metal are the detrital or lithogenic matrix, the Fe and Mn oxyhydroxides and the organic Matter/sulfides, in this order. In general, the spatial distribution of the heavy metals in the reactive phase (defined as the sum of F1-F4) tended to increase in concentration in offshore sediments. The heavy metals in the reactive phase are apparently controlled by the concentration of reactive iron in the sediments, except for Pb, Cd and Ag, suggesting that the latter elements are controlled by other processes, such as particulate matter of biogenic origin. In contrast, the spatial distribution of heavy metals in the detrital phase behaved inversely, that is, the greatest concentrations of metals are found close to the coast off the wastewater treatment plant at Punta Bandera, Baja California. The average concentrations of total metals (sum of F1-F5) were 7.6, 40, 21, 68, 428, 11, 0.10 and 0.025 {mu}g{sup -}1 for Cu, Zn, Ni, Cr, Mn, Pb, Cd and Ag, respectively, and 2.3% for Fe. These concentrations are similar to those reported for uncontaminated reference sediments from southern California, indicating that a large amount of pollutants from the effluent of residual

  16. Parallel rapid HIV testing in pregnant women at Tijuana General Hospital, Baja California, Mexico.

    Science.gov (United States)

    Viani, Rolando M; Araneta, Maria Rosario G; Spector, Stephen A

    2013-03-01

    The objectives of this study were to evaluate the performance of parallel rapid HIV testing and the presence of HIV-associated risk factors in pregnant women with unknown HIV status in Baja California, Mexico. Pregnant women attending the delivery unit or the prenatal clinic at Tijuana General Hospital had blood drawn for parallel rapid HIV testing with Determine™ HIV-1/2 and Uni-Gold™ Recombigen(®) HIV. The parallel rapid HIV test performance was compared to the enzyme immunoassay (EIA) and western blot. From September 2007 to July 2008, 1,383 (94%) of 1,464 women in labor and 1,992 (96%) of 2,075 women in prenatal care were enrolled. The HIV seroprevalence among women screened during labor (19/1,383, 1.37%, 95% CI: 0.85-2.18%) was significantly higher compared to those seeking prenatal care (5/1,992, 0.25%, 95% CI: 0.09-0.62%; pwomen testing positive by parallel rapid HIV testing 24 had a positive confirmatory western blot and one (0.03%) was confirmed as false positive. Additionally, two (0.06%) women had parallel rapid HIV discordant testing results; both tested negative by western blot. All women who tested negative by rapid testing had negative results on pooled EIA antibody testing. The overall sensitivity, specificity, and positive and negative predictive values of parallel rapid HIV testing were 100%, 99.9%, 96%, and 100%, respectively. These findings document a very high acceptance rate and an excellent performance of the parallel rapid HIV testing strategy during pregnancy.

  17. Geophysical characterization of subaerial hydrothermal manifestations in Punta Banda, Baja California, Mexico.

    Science.gov (United States)

    Flores-Marquez, L.; Prol-Ledesma, R. M.; Arango, C.; Canet, C.

    2009-04-01

    Important growth of population in Baja California Peninsula has triggered the need for energy and fresh water. The most sustainable possibility for increasing the availability of fresh water is the use of renewable energy sources in desalination plants. The abundance of geothermal manifestations in the peninsula provides a reliable energy source for desalination purposes. Geothermal development of the Baja California Peninsula dates from the 70's, when the Cerro Prieto geothermal field started producing electricity. Two important cities, Tijuana and Ensenada, are located in the north-western area of Baja California. The city of Ensenada has a desalination plant that is due to be replaced and the geothermal resources of the area could be an option for the new desalination plant. Punta Banda, a region near Ensenada, was specially investigated to determine its geothermal potential. Subaerial springs and the submarine vents were sampled and studied in this work, also geological and geochemical studies were performed, moreover geoelectrical surveys were accomplished to characterize the hydrothermal system at depth. Even though saline intrusion is a severe problem in Ensenada (TDS higher than 3000), thermal springs away from the coast and coastal springs have salinities lower than sea water. According to the geoelectrical models obtained from profiles, the inferred conductive features can be related to thermal anomalies. The existence of hot springs located along a trend suggests that the dynamic of the thermal fluid is restricted by secondary faults.

  18. Review of Neopalpa Povolný, 1998 with description of a new species from California and Baja California, Mexico (Lepidoptera, Gelechiidae)

    Science.gov (United States)

    Nazari, Vazrick

    2017-01-01

    Abstract The monotypic genus Neopalpa was described in 1998 by Czech entomologist Dalibor Povolný based on two male specimens from Santa Catalina Island, California, which he named Neopalpa neonata. The female of this species was discovered recently based on a DNA barcode match and is described. In addition, a new species with marked differences in morphology and DNA barcodes from southern California and Baja California Mexico is described as Neopalpa donaldtrumpi sp. n. Adults and genitalia of both species are illustrated, new diagnosis for the genus Neopalpa is provided, and its position within Gelechiidae is briefly discussed. PMID:28228677

  19. Hybrid system of generating electricity, solar eolic diesel San Juanico, Baja California Sur, Mexico; Sistema hibrido de generacion electrica, eolico solar diesel San Juanico, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Huerta, Javier [Comision Federal de Electricidad, La Paz, Baja California Sur (Mexico); Johnston, Peter [Technology Development, Arizona (United States); Napikoski, Chester [Generation Engineering, Arizona (United States); Escutia, Ricardo [Comision Federal de Electricidad, Baja California Sur (Mexico)

    2000-07-01

    The Comision Federal de Electricidad (CFE), and the northamerican electric company Arizona Public Service (APS), made an agreement of collaboration to develop a project of generating electricity with the use of renewable resources. The premises that where agreed on are the following: 1. Focus the project a rural community. 2. The cost of the whole project should be lower than compared to the interconnection to a conventional system. 3. Acceptance of the community, and the governmental authorities. 4. Sustentability of the operation of the system. Several technical and economical analysis where done, such as the evaluation of the solar and eolic resources, study of the environmental impact, negotiation agreements so it would be possible to obtain de economical resources from Niagara Mohawk (NIMO), and the USAID, all of this thru the supervising of the Sandia National Laboratories. After the anemometric and solar radiation measures where made, it was considered that the community of San Juanico, en Baja California Sur, Mexico, was the most feasible one, it was necessary also to consider the aspects of logistics, socials, size of the community and as a detonator for the economic activities of tourism and fishing. The APS formulated the executive project in accordance with the recommendations of the different areas of CFE. The project consists basically in the installation of 10 wind generators of 10 Kw, a battery bank for 432 KWh, plus a diesel generator for emergencies of 80 Kw. Besides the civil and electromechanical installation. It was necessary to involve the community in the knowledge and followup of the project form it's, considering that this factor would be essential, so it could be successful. Lamps of low consumption where installed on the houses and street lightning, to optimize the system. The patronato that is a civil association of the community, is in charge of the administration of the system, it receives support from personnel of CFE. The income

  20. Late Quaternary Alluvial Fans of Southern Baja California, Mexico: Relation to Eastern Pacific Tropical Cyclones

    Science.gov (United States)

    Antinao, J.; McDonald, E.

    2009-12-01

    In the arid, non-glaciated regions of the Southwestern USA and Northwestern Mexico, aggradation in alluvial fan systems has been traditionally linked to cold and humid periods (e.g., Last Glacial Maximum) or to the transition to warm periods (e.g., the Pleistocene-Holocene transition, PHT). However, major intervals of sediment transport and aggradation have also occurred during climatically warm periods in these regions. These periods have also been identified as portraying enhanced humidity or “monsoonal’ conditions. Investigations on the weather systems able to perform geomorphic work during predominantly warm periods, i.e. the North American Monsoon (NAM) and Eastern Pacific (EP) Tropical Cyclones (TCs), have concentrated mainly in the USA. To understand the relative contribution of these systems to sediment transport over millennial timescales, we have mapped and characterized preliminarily the alluvial fans in four different areas of the Southern Baja California peninsula, Mexico. This region is dominated by EPTC precipitation, which in turn is driving the sediment transport along alluvial channels. Detailed geomorphologic mapping shows that a distinct Late Quaternary chronostratigraphy of alluvial fan units can be developed using geochronological and pedological tools. Specifically, a soil chronosequence can be compared to sequences in the SW USA, allowing a correlation to Late Pleistocene - Holocene events in the region. At least five alluvial units can be identified. Older units have well defined gravel pediments, Av and B horizons and pervasive pedogenic carbonate morphology, with alluvial terraces that rise tens of meters above the present channel. Intermediate age units have developed B horizons and carbonate morphology at different stages. The younger units have thin soil horizons, no carbonate morphology in the soil profile, and some of them are subject to episodic flooding during TC activity. The chronosequence developed is the first step towards

  1. Challenges and opportunities for implementing sustainable energy strategies in coastal communities of Baja California Sur, Mexico

    Science.gov (United States)

    Etcheverry, Jose R.

    This dissertation explores the potential of renewable energy and efficiency strategies to solve the energy challenges faced by the people living in the biosphere reserve of El Vizcaino, which is located in the North Pacific region of the Mexican state of Baja California Sur. This research setting provides a practical analytical milieu to understand better the multiple problems faced by practitioners and agencies trying to implement sustainable energy solutions in Mexico. The thesis starts with a literature review (chapter two) that examines accumulated international experience regarding the development of renewable energy projects as a prelude to identifying the most salient implementation barriers impeding this type of initiatives. Two particularly salient findings from the literature review include the importance of considering gender issues in energy analysis and the value of using participatory research methods. These findings informed fieldwork design and the analytical framework of the dissertation. Chapter three surveys electricity generation as well as residential and commercial electricity use in nine coastal communities located in El Vizcaino. Chapter three summarizes the fieldwork methodology used, which relies on a mix of qualitative and quantitative research methods that aim at enabling a gender-disaggregated analysis to describe more accurately local energy uses, needs, and barriers. Chapter four describes the current plans of the state government, which are focused in expanding one of the state's diesel-powered electricity grids to El Vizcaino. The Chapter also examines the potential for replacing diesel generators with a combination of renewable energy systems and efficiency measures in the coastal communities sampled. Chapter five analyzes strategies to enable the implementation of sustainable energy approaches in El Vizcaino. Chapter five highlights several international examples that could be useful to inform organizational changes at the federal

  2. Geological synthesis of Las Tres Virgenes geothermal area, Baja California Sur, Mexico. Sintesis geologica de la zona geotermica de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Hernandez, Aida (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico))

    1998-01-15

    The Las Tres Virgenes geothermal area is placed in middle Baja California Peninsula, in a zone affected by deformational events since Late Miocene. As a result of tensional stress, NW-SE faults were generated. During this process the Santa Rosalia basin was formed starting the deposition of marine sediments. At the same time La Reforma and Aguajito volcanic centers were emplaced, their deposits were interfingered with sand deposits. At the end of the volcanic activity at Aguajito, the stress regimen changed, old normal faults were reactivated as lateral faults and a pull apart system was initiated. NE-SW and NNE-SSW faults resulted from this deformational stage, and Las Tres Virgenes volcanic products were erupted through this weakness zone. The hydrothermal active system is hosted in a grid constructed by NE-SW, NW-SE faults within the granodioritic basement under the El Azufre volcano. The fluid's discharged take place at Las Viboras zone where intense superficial fracturing is present, associated with El Azufre dextral fault. Drilling results from seven wells confirm the existence of high temperatures making feasible the exploitation of this resource to generate electric energy.

  3. An application of neural network in geophysical prospecting. Electrical resistivity at Las Virgenes geothermal field, Baja California Sur, Mexico; Una aplicacion de las redes neuronales a la prospeccion geofisica. Resistividad electrica en las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2000-12-01

    The technology of the neural network is presented with geophysical focus in the Las Virgenes geothermal field, Baja California Sur, Mexico. The results obtained when extrapolating the associative data of the prospecting magnetoteluria and Vertical Electric Sounding, on the area of the geothermal wells to the rest of the area, allows to classify zones of interest for the geothermal exploitation. Also, the use of these associative parameters with the information of the stabilized temperature of the wells, they allow to predict temperatures for the rest of the area. [Spanish] Se presenta una aplicacion de la tecnologia de las redes neuronales con enfoque geofisico en el campo geotermico de Las Virgenes, Baja California Sur, Mexico. Los resultados obtenidos al extrapolar los datos asociativos de las prospecciones geoelectricas de magnetoteluria y sondeos electricos verticales, en la zona de los pozos geotermicos al resto del area, permiten clasificar zonas de interes para la explotacion geotermica. Tambien, la utilizacion de estos parametros asociativos con la informacion de la temperatura estabilizada de los pozos, permiten predecir temperaturas para la misma area.

  4. Lanthanide behavior in hypersaline evaporation ponds at Guerrero Negro, Baja California, Mexico - an environment with halophiles

    Science.gov (United States)

    Choumiline, K.; López-Cortés, A.; Grajeda-Muñoz, M.; Shumilin, E.; Sapozhnikov, D.

    2013-12-01

    Lanthanides are known, in some cases, to be sensitive to changes in water column or sediment chemistry, a fact that allows them to be used as environmental fingerprints. Nevertheless, the behavior of these elements in hypersaline environments is insufficiently understood, especially in those colonized by bacteria, archaea and eukarya halophiles. Extreme environments like the mentioned exist in the artificially-controlled ponds of the 'Exportadora de Sal' salt-producing enterprise located in Guerrero Negro (Baja California, Mexico). Sediment cores from various ponds were collected, subsampled and measured by ICP-MS and INAA. This allowed differencing the behavior of lanthanides and trace elements under a water column salinity gradient along the evaporation sequence of ponds. Sediment profiles (30 mm long), obtained in Pond 5, dominated by Ca and Mg precipitation and at the same time rich in organic matter due to bacterial mat presence, showed highs and lows of the shale-normalized patterns along different in-core depths. Two groups of elements could be distinguished with similar trends: set A (La, Ce, Pr and Nd) and set B (Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu). The first 'group A' had two prominent peaks at 15 mm and around 22 mm, whereas the 'group B' showed only slight increase at 15 mm and none at 22 mm. Microscopic analyses of prokaryotic cells of a stratified mat in Pond 5 (collected in 2004) showed filamentous bacteria and cyanobacteria with a cell abundance and morphotype richness maxima of prokaryotic cells in a chemocline from 3 mm to 7 mm depth which co-exists nine morphotypes of aerobic and anaerobic prokaryotes Microcoleus chthonoplastes, Leptolyngbya, Cyanothece, Geitlerinema, Spirulina, Chloroflexus, Beggiatoa, Chromatium and Thioploca. Below the 7 mm depth, oxygenic photosynthesis depletes and sulfur reducing compounds increase. The highs of the shale-normalized lanthanide contents of the 'group A' (at 15 mm depth) seem to correlate with the

  5. Preferencias de leche fresca de bovino del consumidor de Baja California, Mexico

    OpenAIRE

    Iliana Enriqueta Montaño Méndez; Belem Dolores Avendaño Ruiz; Ana Isabel Acosta Martínez; Francisco Javier Mesías Díaz

    2013-01-01

    El documento tiene como objetivo conocer las preferencias del consumidor de Baja California por leche de bovino y sus hábitos de consumo, así como identificar segmentos para el consumo de leche a partir de los principales atributos como presentación, tipo de grasa y precio, e identificar nichos de mercado para nuevos productos. Para determinar las preferencias del consumidor, se utilizaron técnicas del análisis de conjunto, análisis de segmentación y análisis de simulación. Para lo anterior, ...

  6. Study of the structural control of fluid flow within the Cerro Prieto Geothermal Field, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Noble, J.E.; Manon, M.A.; Lippmann, M.J.; Witherspoon, P.A.

    1977-10-01

    The Lawrence Berkeley Laboratory and the Comision Federal de Electricidad of Mexico are conducting a joint investigation of the Cerro Prieto Geothermal Field, located approximately 35 km south of Mexicali, Baja California, Mexico, in the Sea of Cortez-Salton Trough. Recent analyses of various geophysical/electrical logs, temperature logs, production and geochemical data and the subsequently developed preliminary model of the structure of the geothermal system and the distribution of geothermal fluids are presented. Techniques routinely applied to petroleum exploration were successfully used in the development of a preliminary model of this water-dominated system. The study indicates the upwelling of geothermal fluids along an east bounding fault from a deep, as yet unexplored source. The fluids dissipate into various sand horizons at various depths. The resulting stratigraphic and fluid flow model is of importance in planning additional developments of the Cerro Prieto Geothermal Field.

  7. [Progebiophilus bruscai (Isopoda:Bopyridae) parasitizing the shrimp Upogebia dawsoni (Thalassinoidea:Upogebiidae), in Baja California Sur, Mexico)].

    Science.gov (United States)

    Leija-Tristán, A; Salazar-Vallejo, S I

    1991-06-01

    Parasitism of the isopod Progebiophilus bruscai Salazar-Vallejo & Leija-Tristán over the common mud shrimp, Upogebia dawsoni Williams, was analysed in the Ensenada and Bahia de La Paz, Baja California Sur, Mexico. Mud-shrimps were collected in three similar sites that differ in grain size and in the anthropogenic organic matter enrichment. Four-hundred-nine mud-shrimps were collected; the largest abundance was registered in the organically enriched site, but they were significantly smaller and more heavily parasited than the animals from the site lacking such organic enrichment. The size of the parasite is clearly dependent on the size of the mud-shrimp. This is the first study of the upogebiid-bopyris relationship in Mexico.

  8. Correlation between seismicity and the distribution of thermal and carbonate water in southern and Baja California, United States and Mexico

    Science.gov (United States)

    Gastil, Gordon; Bertine, Kathe

    1986-04-01

    A comparison of the distribution of thermal and thermal-related springs and wells in southern California, United States, and Baja California, Mexico, with the abundance of earthquakes of magnitude 4 or greater shows as close a relationship between thermal waters and the distribution of seismicity as to the distribution of active faults. It appears that the distribution of thermal water variations in the geothermal gradient in turn influences the stress accumulation capability of the rocks at depth. Thus, areas with abundant thermal waters (and hence steep geothermal gradients) release stress by frequent moderate earthquakes; areas lacking thermal waters, such as the central Transverse Ranges, accumulate stresses that are released by infrequent large earthquakes.

  9. The Palaeodiet of the Pericue Indians of the Cape Region of Baja California Sur, Mexico.

    Science.gov (United States)

    Beer, N.; Gonzalez, S.; Huddart, D.; Rosales-Lopez, A.; Lamb, A.

    2008-05-01

    The archaeology of the Pericue Indians inhabiting the Cape region of Baja California has long been an area of interest. The dolichocranic traits exhibited by this population have lead to suggestions that these people were a relic population of an early coastal migration into North America. The antiquity of directly dated Pericue human remains only reaches 3,000 B.P. with occupation sites dating back to 9,000 B.P. The site of Babisuri cave in Isla Espiritu Santo may demonstrate a very early human presence in Baja California Sur between 36,000 to 45,000 B.P. although the exact nature of this evidence is unclear. Increasing tourist development within this region threatens many archaeological sites particularly coastal shell middens and rock shelters. Current rescue excavations are yielding important information regarding many aspects of the culture of the Pericue Indians. Geochemical evidence of diet {d13C and d15N} taken from Pericue bone samples, modern and archaeological animals and modern plants is helping us to understand the complicated subsistence strategies of this group. Initial results highlight a complicated and diverse diet including marine and terrestrial resources, most likely exploited seasonally. Similarities between the diet of the Pericue and other nearby coastal Indian groups are clear and will be discussed. Pericue Indian material culture, combined with the exploitation of marine mammals and the construction of enormous shell mounds display parallels with other central and North American groups. The exploitation of marine mammals and the associated stone tools display striking similarities to the Chumash people of the Channel Islands of Coastal Southern California. Some of these cultural similarities will be highlighted in this presentation. Current genetic work is attempting to discover the nature of the similarities between the Chumash and Pericue groups as some cultural elements of each group have parallels with the other. Initial genetic

  10. Modern carbonate sediments and environments of the LaPaz region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Halfar, J.; Ingle, J.C. Jr. [Stanford Univ., CA (United States); Cruz-Orozco, R. [Universidad Autonoma de Baja California, La Paz (Mexico); Godinez-Orta, L. [Centro Interdisciplinario de Ciencias Marinas, La Paz (Mexico)

    1996-12-31

    The Gulf of California represents one of the most productive and unique marginal seas in the world. The mouth of the Gulf captures warm equatorial water while annual wind patterns assure major upwelling of nutrient-rich water leading to a rich marine biota. These conditions have created a wide array of tropical through warm temperate carbonate environments. The most unusual of these environments is located in the La Paz region of Baja California Sur where tropical-subtropical water temperatures and low rainfall have allowed growth of corals, calcareous red algae, and other shelled invertebrates to form a carbonate bank environment. Sampling and mapping transacts in shallow bays north of La Paz and on the adjacent Espiritu Santo island have revealed a full spectrum of subenvironments including mangrove bordered, terrigenous mud dominated coastal zones, which grade into carbonate tidal flats. In addition, single coral heads as well as incipient reef structures constructed by Porites and Pocillopora coral are present in deeper water areas. Coralline red algae, which are increasingly utilized for paleoenvironmental reconstructions, grow in high abundance on coral debris and in soft sediments and turn out to be main contributors to the La Paz carbonates. Analysis of siliciclastic admixtures, grain size and organic carbon content allow a classification of distinct environments. These data are supplemented by an evaluation of benthic foraminiferal zonations and the varying abundance of biogenic constituents. This Baja California Sur carbonate environment holds special relevance for the interpretation of analogous Neogene and Paleogene paleoenvironments marking major paleoclimatic and paleoceanographic events along the Pacific Coast of North America.

  11. Modern carbonate sediments and environments of the LaPaz region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Halfar, J.; Ingle, J.C. Jr. (Stanford Univ., CA (United States)); Cruz-Orozco, R. (Universidad Autonoma de Baja California, La Paz (Mexico)); Godinez-Orta, L. (Centro Interdisciplinario de Ciencias Marinas, La Paz (Mexico))

    1996-01-01

    The Gulf of California represents one of the most productive and unique marginal seas in the world. The mouth of the Gulf captures warm equatorial water while annual wind patterns assure major upwelling of nutrient-rich water leading to a rich marine biota. These conditions have created a wide array of tropical through warm temperate carbonate environments. The most unusual of these environments is located in the La Paz region of Baja California Sur where tropical-subtropical water temperatures and low rainfall have allowed growth of corals, calcareous red algae, and other shelled invertebrates to form a carbonate bank environment. Sampling and mapping transacts in shallow bays north of La Paz and on the adjacent Espiritu Santo island have revealed a full spectrum of subenvironments including mangrove bordered, terrigenous mud dominated coastal zones, which grade into carbonate tidal flats. In addition, single coral heads as well as incipient reef structures constructed by Porites and Pocillopora coral are present in deeper water areas. Coralline red algae, which are increasingly utilized for paleoenvironmental reconstructions, grow in high abundance on coral debris and in soft sediments and turn out to be main contributors to the La Paz carbonates. Analysis of siliciclastic admixtures, grain size and organic carbon content allow a classification of distinct environments. These data are supplemented by an evaluation of benthic foraminiferal zonations and the varying abundance of biogenic constituents. This Baja California Sur carbonate environment holds special relevance for the interpretation of analogous Neogene and Paleogene paleoenvironments marking major paleoclimatic and paleoceanographic events along the Pacific Coast of North America.

  12. Proceedings of the Binational Conference on Libraries in California and Baja California (1st, Tijuana, Baja California, Mexico, January 13-14, 1984) = Memorias de la Primera Conferencia Binacional de Bibliotecas de las Californias.

    Science.gov (United States)

    Ayala, Marta Stiefel, Ed.; And Others

    This document includes the text of presentations given at the First Binational Conference on Libraries in California and Baja California, as well as minutes from four roundtables held at the conference. Following a prologue and a brief background on the conference, the following presentations are included: (1) "State Support for Public…

  13. Louse flies on birds of Baja California.

    Science.gov (United States)

    Tella, J L; Rodríguez-Estrella, R; Blanco, G

    2000-01-01

    Louse flies were collected from 401 birds of 32 species captured in autumn of 1996 in Baja California Sur (Mexico). Only one louse fly species (Microlynchia pusilla) was found. It occurred in four of the 164 common ground doves (Columbina passerina) collected. This is a new a host species for this louse fly.

  14. Prevalence of infection with Toxoplasma gondii in landrace and mixed breed pigs slaughtered in Baja California Sur State, Mexico.

    Science.gov (United States)

    Alvarado-Esquivel, Cosme; Vazquez-Morales, Renata Fabiola; Colado-Romero, Edgar Eusebio; Guzmán-Sánchez, Ramiro; Liesenfeld, Oliver; Dubey, Jitender P

    2015-03-01

    We performed a cross-sectional study to determine the seroprevalence of Toxoplasma gondii infection in 308 domestic pigs slaughtered in La Paz, Baja California Sur State, Mexico using the modified agglutination test (MAT, cut off 1:25). Forty (13%) of the 308 pigs were seropositive with MAT titers of 1:25 in 16, 1:50 in 5, 1:100 in 4, 1:200 in 5, 1:400 in 3, 1:800 in 3, 1:1600 in 2, and 1:3200 in 2. Multivariate analysis of pigs' characteristics showed that seropositivity to T. gondii was negatively associated with mixed breed (OR = 0.02; 95% CI: 0.003-0.26; P = 0.001). Other variables including sex, type of raising, and municipality did not show an association with T. gondii seropositivity by multivariate analysis. The frequency of high antibody titers (≥1:400) was significantly higher (P Landrace pigs than mixed breed pigs. The seroprevalence of T. gondii infection in pigs for slaughter in Baja California Sur State is low compared with seroprevalences reported in pigs in other Mexican states. Landrace pigs demonstrated higher seroprevalence rates and antibody levels than mixed breed pigs. This is the first report of T. gondii infection in pigs raised in a desert climate.

  15. MT data modelling at Las Tres Virgenes, Baja California Sur, Mexico, geothermal zone. Modelado de datos magnetotelurgicos en el campo geotermico de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico))

    1998-01-15

    An interpretation of MT soundings at the Las Tres Virgenes, Baja California Sur, Mexico, geothermal project, was conducted, to actualize the geoelectric model of the reservoir, with the support provided by new drilling data. MT data were collected during the Comision Federal de Electricidad 1992 and 1994 campaigns. The use of apparent resistivity maps, tipper and apparent profiles lets us to identify TE and TM modes, as well as the lateral variations related to structural geology changes. These results were used to prepare sections based on Bostick inversion of TE mode of each sounding. Results were correlated to lithology reported by recent exploratory drilling. MT comprehensive studies let us delineate the reservoir limits, and the main geologic structures related to geothermal fluids production.

  16. Net primary productivity, upwelling and coastal currents in the Gulf of Ulloa, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    E. González-Rodríguez

    2011-09-01

    Full Text Available The Gulf of Ulloa, a highly productive area off the western coast of Baja California Peninsula, is examined for five successive years (2003–2007 by using satellite data and seasonal net primary productivity estimates obtained by a vertical generalized production model. The results clearly identify a seasonal signal of coastal upwelling in productivity estimates. Highest values occur from May to June and sometimes July. We also find influence of an equatorward coastal current able of transporting water from neighboring north upwelling areas to the Gulf of Ulloa in winter–spring. This flow contributes to increase the seasonal net primary productivity. The opposite occurs in summer, when a warm poleward current of tropical characteristics arrives to the region. Our findings reveal that such warm coastal current suppressed the productivity in the whole.

  17. Hazardous waste shipping in the northern border of Mexico: The situation of Baja California

    Directory of Open Access Journals (Sweden)

    Ramón A. Castillo Ponce

    2013-01-01

    Full Text Available In this document we evaluate the determinants of shipments of hazardous waste to the US. We consider a sample of firms operating in the state of Baja California for the 2008–2010 sample period. The analysis consists on the estimation of two econometric specifications. The first refers to a truncated model in the spirit of Tobit. The second is a probabilistic model. The results of the Tobit model suggest that size, location and origin of the firm influence the amount of shipments. In particular, shipments are positively associated with larger firms; those located in the municipality of Tijuana and those whose origin is foreign. The probabilistic model finds that a depreciation of the Mexican peso contributes to an increase in the likelihood of sending a shipment. This may be the result of an improvement in the border economic environment due to the depreciation of the currency.

  18. Plio-pleistocene volcano-tectonic evolution of la Reforma Caldera, Baja California, Mexico

    Science.gov (United States)

    Demant, Alain; Ortlieb, Luc

    1981-01-01

    La Reforma volcanic complex, in east-central Baja California, shows a characteristic caldera structure, 10 km in diameter. The first eruptive stage, during the Pliocene, was manifested by ash and pumice falls and by subaqueous pumitic flows. In a second stage basic flows were deposited in a near-shore environment (subaerial and pillow lavas). During the early Pleistocene a large ignimbritic eruption, producing mainly pantelleritic tuffs, immediately predated the formation of the caldera itself. Afterwards, along marginal fractures of the caldera, some rhyolitic domes and flows partially covered the thick ignimbritic sheet. A block of Miocene substratum, in the center of the caldera, has been uplifted, nearly 1 km, by "resurgent doming". Small outcrops of diorite might constitute the top of coarse-grained crystallized magmatic bodies, and thus support the "resurgent doming" interpretation. A few basaltic cones were finally built on the flanks of the caldera complex; the latter are not related to the caldera history but to the extension tectonics of the Gulf of California which are also responsible for the Tortuga Island and the Holocene Tres Virgenes tholeiitic cones. South of la Reforma are found the highest (+300 m) Pleistocene marine deposits of the Gulf coast of Baja California. The uplift of this area is due in part to the positive epeirogenic movements of the whole peninsular crustal block, and also to the late doming of the caldera. On the coastal (eastern) flank of La Reforma complex up to seven stepped wave-cut terraces have been preserved, the highest reaching more than +150 m and the lowest ones +25 m. Lateral correlations of the marine terraces along the whole Gulf of California suggest that this volcano-tectonic uplift, that is still active, is of the order of 240 mm/10 3 y. The set of terraces is interpreted to be Middle (700-125 × 10 3y) to Upper (125-80 × 10 3y) Pleistocene, and is tentatively correlated with the paleoclimatic chronology of deep

  19. Ostracode Paleoecology and Trace Element Shell Chemistry: A case study from Laguna Salada, Baja California, Mexico.

    Science.gov (United States)

    Romero-Mayen, V.; Bernal, J.; Palacios-Fest, M.; Carreno, A.

    2007-05-01

    The Laguna Salada Basin in northeastern Baja California constitutes the southwestern limit of the Salton Trough and provides insights into the evolution of marine and non-marine sedimentary basins during the latest Neogene at the head of the Gulf of California. A 43 m long core (LS04-1) recovered from the Basin consisted of alternating clay, silt and sand beds with gypsum lenses. Three radiocarbon dates provided the age control: 41,520±790 cal years BP at 30.21 m, 25,590±320 cal years BP at 26.60 m and 15,150±70 cal years BP at 7.50 m. A total of 103 samples were analyzed for taxonomy, taphonomy and geochemistry. Eighteen marine and brackish- water ostracode species and nine benthic foraminifera species were identified. Faunal changes suggest variations in the water source with the opening of the basin to the Gulf of California. The Mg/Ca and Sr/Ca ratios of valves of two ostracode species (Limnocythere staplini and Cyprideis castus) were measured using ICPMS. Based on the Mg/Ca ratios, water paleotemperatures were estimated using a regression model. Shell chemistry shows mixed results. Some intervals fit an acceptable range, whereas other are unrealistic. Analysis of Sr/Ca ratios ostracode valves from the conflicting horizons show evidence of diagenetic effects. The fossil assemblages indicate two dry periods: prior to the 41,520 cal years BP and after the 15 ,150 cal years BP, with the maximum highstand of the basin between 25,590 and 15,150 cal years BP. Given the diagenetic effects at Laguna Salada, ostracode shell chemistry paleotemperature estimates may not be warranted in attempting to determine this parameter from the dry periods shown by faunal assemblages.

  20. Late Quaternary Faulting along the San Juan de los Planes Fault Zone, Baja California Sur, Mexico

    Science.gov (United States)

    Busch, M. M.; Coyan, J. A.; Arrowsmith, J.; Maloney, S. J.; Gutierrez, G.; Umhoefer, P. J.

    2007-12-01

    As a result of continued distributed deformation in the Gulf Extensional Province along an oblique-divergent plate margin, active normal faulting is well manifest in southeastern Baja California. By characterizing normal-fault related deformation along the San Juan de los Planes fault zone (SJPFZ) southwest of La Paz, Baja California Sur we contribute to understanding the patterns and rates of faulting along the southwest gulf-margin fault system. The geometry, history, and rate of faulting provide constraints on the relative significance of gulf-margin deformation as compared to axial system deformation. The SJPFZ is a major north-trending structure in the southern Baja margin along which we focused our field efforts. These investigations included: a detailed strip map of the active fault zone, including delineation of active scarp traces and geomorphic surfaces on the hanging wall and footwall; fault scarp profiles; analysis of bedrock structures to better understand how the pattern and rate of strain varied during the development of this fault zone; and a gravity survey across the San Juan de los Planes basin to determine basin geometry and fault behavior. The map covers a N-S swath from the Gulf of California in the north to San Antonio in the south, an area ~45km long and ~1-4km wide. Bedrock along the SJPFZ varies from Cretaceous Las Cruces Granite in the north to Cretaceous Buena Mujer Tonalite in the south and is scarred by shear zones and brittle faults. The active scarp-forming fault juxtaposes bedrock in the footwall against Late Quaternary sandstone-conglomerate. This ~20m wide zone is highly fractured bedrock infused with carbonate. The northern ~12km of the SJPFZ, trending 200°, preserves discontinuous scarps 1-2km long and 1-3m high in Quaternary units. The scarps are separated by stretches of bedrock embayed by hundreds of meters-wide tongues of Quaternary sandstone-conglomerate, implying low Quaternary slip rate. Further south, ~2 km north of the

  1. Thermal evolution of a sheared continental margin: Insights from the Ballenas transform in Baja California, Mexico

    Science.gov (United States)

    Seiler, Christian; Gleadow, Andrew J. W.; Fletcher, John M.; Kohn, Barry P.

    2009-07-01

    The Ballenas transform margin in central Baja California offers an unparalleled opportunity to study the thermal behaviour of a sheared continental margin during various stages of its evolution. Apatite fission track and (U-Th)/He results from two transects perpendicular to the coast reveal a pronounced latest Pliocene to Pleistocene (~ 1.8 Ma) heating event related to the Neogene opening of the Gulf of California. Proximity to a regional pre-rift unconformity indicates that samples remained at near-surface levels since Paleogene unroofing, despite having experienced reheating to maximum paleotemperatures within or above the fission track partial annealing zone. In general, maximum paleotemperatures during overprinting decrease from > 100-120 °C near the coast to below 60 °C ca. 5-8 km further inland, suggesting lateral heat flow from a source within the Gulf of California. Heat sources related to the structural development of the Ballenas transform fault, located approximately 1.5-4.5 km offshore from the two sample transects, most likely controlled the observed reheating. Overprinting patterns do not support conductive reheating due to reburial, magmatism or frictional shear. Instead, a pronounced thermal spike in between much less overprinted neighbouring samples strongly favours convective heating by hydrothermal fluids as the dominant overprinting process. Hydrothermal activity may be caused by either deep fluid circulation along newly formed shear zones of the transform fault or, more likely, magmatic leaking along the transform fault. Latest Pliocene to Pleistocene (~ 1.8 Ma) activity on the Ballenas transform fault is closely linked to extension in the Lower and Upper Delfín basins and provides a minimum age for the structural reorganisation and the relocation of extension in the northern Gulf of California. This study shows that hydrothermal activity can cause significant thermal events in a transform margin before the passage of the spreading centre

  2. Geothermal Exploration Using Remote Sensing in the South of Baja California Sur, Mexico

    Science.gov (United States)

    Báncora, Cristina; Prol-Ledesma, Rosa María

    2008-05-01

    The area from Ciudad Constitución to Los Cabos in Baja California Sur was studied using a mosaic of four Landsat ETM+images. The main objective was to define favorable areas for utilization and exploitation of geothermal energy. The approach was to spectrally and spatially enhance the images to define characteristics related with geothermal activity, as are the presence of altered rock and main geological structures. The products of hydrothermal alteration are minerals that belong to two main groups: oxides and hydroxyls. Therefore, image processing is necessary to enhance oxides and hydroxyls spectral features and subdue the vegetation spectral characteristics. The band subtraction (4-3, 3-1, 5-7) gave the finest results due to the fact that it is a linear equation that does not cause loss of information when it is stretched. A color composite was done with these three layers and after a detailed visual analysis three areas were point out to be prospective to contain hydrothermal activity.

  3. Key species and impact of fishery through food web analysis: A case study from Baja California Sur, Mexico

    Science.gov (United States)

    Rocchi, Marta; Scotti, Marco; Micheli, Fiorenza; Bodini, Antonio

    2017-01-01

    Ecosystem-Based Management (EBM) aims to support the protection of natural ecosystems and to improve economic activities. It requires considering all of the actors interacting in social-ecological systems (e.g., fish and fishers) in the understanding that their interplay determines the dynamic behavior of the single actors as well as that of the system as a whole. Connections are thus central to EBM. Within the ecological dimension of socio-ecological systems, interactions between species define such connections. Understanding how connections affect ecosystem and species dynamics is often impaired by a lack of data. We propose food web network analysis as a tool to help bridge the gap between EBM theory and practice in data-poor contexts, and illustrate this approach through its application to a coastal marine ecosystem in Baja California Sur, Mexico. First, we calculated centrality indices to identify which key (i.e., most central) species must be considered when designing strategies for sustainable resource management. Second, we analyzed the resilience of the system by measuring changes in food web structure due to the local extinction of vulnerable species (i.e., by mimicking the possible effect of excessive fishing pressure). The consequences of species removals were quantified in terms of impacts on global structural indices and species' centrality indices. Overall, we found that this coastal ecosystem shows high resilience to species loss. We identified species (e.g., Octopus sp. and the kelp bass, Paralabrax clathratus) whose protection could further decrease the risk of potential negative impacts of fishing activities on the Baja California Sur food web. This work introduces an approach that can be applied to other ecosystems to aid the implementation of EBM in data-poor contexts.

  4. Climate and upper ocean variability off Baja California, Mexico: 1997-2008

    Science.gov (United States)

    Durazo, Reginaldo

    2009-12-01

    Temperature and salinity anomalies derived from observations obtained in the period 1997-2008 are used to study the changes in physical properties off the Baja California west coast (24-31 N). Near surface anomalies were used to characterize four periods of distinctive variability: (1) a warm and saline phase of El Niño 1997-1998, (2) a saline period from 1999 to 2002, (3) fresh subarctic water in 2002-2006, and (4) a saline-fresh (El Niño-La Niña) phase in late 2006 to early 2008. Subsurface (200 m) salinity anomalies depicted a trend towards saltier conditions (ΔS ∼ 0.1) from 2001 onwards, and did not show the four periods discernible near surface. EOF analysis of sea surface wind stress and wind stress curl suggested that after the intense westerly winds in late 2001, freshening during late 2002-2006 was due to the weakening (strengthening) of the North Pacific Current (Aleutian Low), and to a decrease of wind stress curl produced upwelling. Data also showed differences in the timing and magnitude of anomalies observed between the north (poleward of 28 N) and the south (equatorward of 28 N). Subsurface geostrophic currents demonstrated the existence of two large scale cyclonic gyres, one associated with a subarctic domain in the northern region, and another having tropical characteristics. The likely role of subsurface cyclonic pairs in the definition of a provincial boundary, and the importance in influencing the CCS ecosystem, are discussed.

  5. Terrain complexity characterization in the eastern coast of Baja California Sur, Mexico

    Science.gov (United States)

    Martínez Flores, G.; Nava-Sanchez, E. H.; Segovia Zavala, J. A.

    2013-05-01

    Terrain complexity is an important feature for geomorphological analysis and characterization, since it is associated with processes that control the landscape evolution, giving rise to geological formations of varying topographic complexity. In the geometrical sense, the terrain complexity depicts the shape of the landform surface or cross section, such as rugosity, curvature, fractal dimension, slope, aspect, etc. Moreover, the coastline complexity or indentation index has been used as an auxiliary parameter in coastline characterization. Currently, there are a variety of terrain and shoreline complexity indexes, derived from digital elevation models and digital coastlines, respectively, which usually are evaluated and interpreted independently. In this work the evaluation of these indexes was implemented in twenty watersheds of the eastern coast of the Mexican state of Baja California Sur. To evaluate the terrain complexity index, the slope, profile curvature and roughness were computed and weighted. For this purpose the digital elevation model of 30 m resolution, obtained from the National Institute of Statistics and Geography (INEGI) was used. The coastline complexity was assessed based on the variability of angles of coastline segments, as are defined in the Global Self-consistent, Hierarchical, High-resolution Geography Database (GSHHG). Five classes were identified for each index, whose distribution was represented by digital cartography. In general, the gullies have the highest terrain complexity, while the lower values correspond to areas of alluvial fans and other areas of sedimentation close to the shoreline. The spatial distribution of these indexes could be useful to mapping terrain classification and as support to analyze geological and oceanographic processes that influence this region.

  6. Morphology and sedimentology of two contemporary fan deltas on the southeastern Baja California Peninsula, Mexico

    Science.gov (United States)

    Nava-Sanchez, Enrique; Cruz-Orozco, Rodolfo; Gorsline, Donn S.

    1995-08-01

    The San Juan de Los Planes drainage basin is located on the southeastern margin of the Baja California Peninsula, approximately 20 km southeast of the city of La Paz. Pleistocene alluvial fans have been built into the basin from the surrounding areas of high relief and are presently being eroded. At the fan apex, the dissection depth ranges from 20 to 40 m, and is 6 to 15 m at the coast. The sediments have been redeposited in several active modern fan deltas built out into the narrow shelf of La Ventana Bay. Shelf width ranges from 0 to 5 km (average 3 km). Wave energy is delivered from southeasterly storms and from the local sea breeze winds; the respective wave heights average 2 and 1 m. The Agua Caliente and Las Canoas fan deltas, the subjects of this paper, are located on the active El Sargento Fault Zone and are fed by channels that deeply dissect the older fan surfaces. The Agua Caliente fan delta is a classic Gilbert-type delta with a steeply inclined delta front. Wave reworking and redistribution of the sediments at the delta face are important and a wave-cut terrace has developed at about 6 m depth. The Las Canoas fan delta is a shoal-water-profile, Hjulstrom type with a gently inclined delta front. Wave energy is less important. The alignments of the coasts of both fans are controlled by the fault line. Sediment supply is largest for the Las Canoas fan delta. The fan deltas are examples of this depositional form as it has developed in an arid, tectonically active, high-relief and narrow neo-trailing edge margin.

  7. Occurrence of Landslides during the Approach of Tropical Cyclone Juliette (2001) to Baja California Sur, Mexico

    Science.gov (United States)

    Antinao, J.; Farfan, L.

    2012-12-01

    The approach of Tropical Cyclone Juliette to the Baja California Peninsula in September 2001 triggered at least 419 landslides. Most of the landslides were shallow slips and debris slides, of limited areal extent, which were converted rapidly into debris flows to be exported quickly out of the mountain areas towards the lowlands. Main factors affecting landslide occurrence were total storm rainfall and intensity, aspect, geology and vegetation association. Two processes can be distinguished as initiating slope failure. The first process is linked to failures in concave topography, where accumulation of rainfall from exposed bedrock slopes generated excess overland flow that aggregated to generate a 'fire hose' effect on the base of slopes, mobilizing regolith. A second process involved a combination of wind and excess overland flow developed in the more convex or planar upper slopes, where heterogeneous regolith has formed in time following successional changes in vegetation associations along the oak-dry tropical forest ecotone. In this area, wind uprooted trees that dislodged large regolith and bedrock blocks, priming hillslopes for further runoff concentration. From the analysis of historical information, an estimative threshold curve for triggering landslides in this region is sketched. It was also determined that storms like Juliette approach the southern peninsula on average once every 100 years. Denudation estimates are in the higher end of the spectrum for a tectonically passive margin. These estimates should be considered when taking decisions regarding management of water resources in this area through damming of streams. The results emphasize the need for a more detailed representation of the spatial distribution of the rainfall and winds for this mountainous region frequently affected by the passage of tropical cyclones.

  8. Drug-scene familiarity and exposure to gang violence among residents in a rural farming community in Baja California, Mexico

    Science.gov (United States)

    Volkmann, Tyson; Fraga, Miguel A.; Brodine, Stephanie K.; Iñiguez-Stevens, Esmeralda; Cepeda, Alice; Elder, John P.; Garfein, Richard S.

    2012-01-01

    We examined drug-scene familiarity and exposure to gang violence among residents of a migrant farming community in rural Baja California, Mexico. In October 2010, 164 members of a single colonia (community) underwent an interviewer-administered survey to assess ‘exposure to gang violence’ and ‘drug-scene familiarity’, as well as other health indicators. Logistic regression was used to identify correlates of exposure to gang violence. Overall, 20% of participants were male, the median age was 27 years, 24% spoke an indigenous language, 42% reported exposure to gang violence, and 39% reported drug-scene familiarity. Factors independently associated with exposure to gang violence included being younger (AOR=0.80 per 5-year increase, 95% CI=0.67–0.96), living in the community longer (AOR=1.47 per 5-year increase, 95% CI=1.11–1.72), higher educational attainment (AOR=1.70 per 5-year increase, 95% CI=1.07–1.12), and drug-scene familiarity (AOR=5.10, 95%CI=2.39–10.89). Exposure to gang violence was very common in this community and was associated with drug-scene familiarity, suggesting a close relationship between drugs and gang violence in this rural community. In a region characterised by mass migration from poorer parts of Mexico, where drugs and gangs have not been previously reported, emerging social harms may affect these communities unless interventions are implemented. PMID:23072623

  9. Decreased Anemia Prevalence Among Women and Children in Rural Baja California, Mexico: A 6-Year Comparative Study.

    Science.gov (United States)

    Moor, Molly A; Fraga, Miguel A; Garfein, Richard S; Harbertson, Judith; Rodriguez-Lainz, Alfonso; Rashidi, Hooman H; Elder, John P; Brodine, Stephanie K

    2016-08-01

    Anemia is a public health problem in Mexico. This study sought to determine the prevalence and correlates of anemia among women and children residing in a rural farming region of Baja California, Mexico. An existing partnership between universities, non-governmental organizations, and an underserved Mexican community was utilized to perform cross-sectional data collection in 2004-2005 (Wave 1) and in 2011-2012 (Wave 2) among women (15-49 years) and their children (6-59 months). All participants completed a survey and underwent anemia testing. Blood smears were obtained to identify etiology. Nutrition education interventions and clinical health evaluations were offered between waves. Participants included 201 women and 99 children in Wave 1, and 146 women and 77 children in Wave 2. Prevalence of anemia significantly decreased from 42.3 to 23.3 % between Waves 1 and 2 in women (p women in Wave 1, consumption of iron absorption enhancing foods (green vegetables and fruits high in vitamin C) was protective against anemia (p = 0.043). Women in Wave 2 who ate ≥4 servings of green, leafy vegetables per week were less likely to be anemic (p = 0.034). Microscopic examination of blood smears revealed microcytic, hypochromic red blood cells in 90 % of anemic children and 68.8 % of anemic women, consistent with iron deficiency anemia.

  10. Drug-scene familiarity and exposure to gang violence among residents in a rural farming community in Baja California, Mexico.

    Science.gov (United States)

    Volkmann, Tyson; Fraga, Miguel A; Brodine, Stephanie K; Iñiguez-Stevens, Esmeralda; Cepeda, Alice; Elder, John P; Garfein, Richard S; Viidai Team

    2013-01-01

    We examined drug-scene familiarity and exposure to gang violence among residents of a migrant farming community in rural Baja California, Mexico. In October 2010, 164 members of a single colonia (community) underwent an interviewer-administered survey to assess 'exposure to gang violence' and 'drug-scene familiarity', as well as other health indicators. Logistic regression was used to identify correlates of exposure to gang violence. Overall, 20% of participants were male, the median age was 27 years, 24% spoke an indigenous language, 42% reported exposure to gang violence and 39% reported drug-scene familiarity. Factors independently associated with exposure to gang violence included being younger (adjusted odds ratio [AOR] =0.80 per 5-year increase, 95% confidence interval [CI]=0.67-0.96), living in the community longer (AOR=1.47 per 5-year increase, 95% CI=1.11-1.72), higher educational attainment (AOR=1.70 per 5-year increase, 95% CI=1.07-1.12) and drug-scene familiarity (AOR=5.10, 95% CI=2.39-10.89). Exposure to gang violence was very common in this community and was associated with drug-scene familiarity, suggesting a close relationship between drugs and gang violence in this rural community. In a region characterised by mass migration from poorer parts of Mexico, where drugs and gangs have not been previously reported, emerging social harms may affect these communities unless interventions are implemented.

  11. Frecuencias de grupos sanguíneos e incompatibilidades ABO y RhD, en La Paz, Baja California Sur, México Blood group ABO and RhD frequencies and incompatibilities in La Paz, Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Lorenzo del Peón-Hidalgo

    2002-09-01

    (Zone General Hospital of the Mexican Institute of Social Security in La Paz, Baja California Sur, Mexico. Blood donors were typified by tube agglutination. The gene frequencies were estimated assuming equilibrium conditions, and incompatibilities and alloimmunization were statistically assessed with the chi² test. Results. Percent frequencies were as follows: blood group O, 58.49%; A, 31.40%; B, 8.40%; AB, 1.71%; RhD, 95.36%; and RhD negative, 4.64%. Genic frequencies were: i, 0.7648; I A, 0.1821; I B, 0.0519; D, 0.7845; and d, 0.2155, respectively. Incompatibilities between couples and mother-child were 0.3023 and 0.1685 for ABO, 0.0442 and 0.0364 for RhD, and 0.0134 and 0.0061 for double incompatibility, respectively. The probability of maternal alloimmunization was estimated at 0.0309. Conclusions. The O and RhD groups were the most common in La Paz, although frequencies were among the lowest in Mexico, contrary to the case of A and RhD negative groups. The probabilities of maternal alloimmunization and of incompatibilities were also high. Ancestral white, black, and indigenous groups admixed in the northwestern part of Mexico; after migrating to Baja California Sur the admixture of the population probably became similar to that of the remainder of the northwestern area.

  12. Subsidence History of the Laguna Salada Basin in Northeastern Baja California, Mexico

    Science.gov (United States)

    Contreras, J.; Martin-Barajas, A.; Herguera, J.

    2008-12-01

    The Salton Trough region in southern California and the Mexicali valley in northwestern Mexico are areas of (i) rapid subsidence due to trans-tension along the San Andreas-Imperial fault system, and (ii) high flux of sediments transported by the Colorado River, all of which confer this region with a high potential to preserve a complete record of climatic and tectonic activity information. Here we present the subsidence history of the Laguna Salada basin, and the history of activity of the master bounding faults on its eastern side. The Laguna Salada is a lacustrine basin located west of the Mexicali valley and to the south of the Salton Trough. Sedimentological as well as time series analyses performed on two 42 m-long cores drilled in the center of the basin, estimated to span the past 50 and 70KaBP, indicate a modulation of the late Quaternary stratigraphy by cyclic variations in lake level driven by Milankovitch forcing. Based on these results we derive the long-term history of the basin from a gamma-ray log recovered from a 2.8 km-deep geothermal borehole drilled by the Mexican Power Company adjacent to the Laguna Salada fault. The stratigraphy of the deep borehole reveals a history of activity pulses related to the initial breakage of the Laguna Salada fault and its interaction with neighboring faults. A first pulse started at 1.5 Ma and records the initiation of the Laguna Salada fault and rapid uplift of the crystalline block of the Sierra Cucapa. A second pulse started around 1 Ma, and is very likely related to the hard linking of the Laguna Salada fault with the Cañada David detachment by the Cañon Rojo fault. The onset of the Laguna Salada fault at 1.5 Ma appears to be synchronous with an early Pleistocene regional fault reorganization among the San Jacinto, San Andreas and Elsinore fault systems in southern California, suggesting that this reorganization may have affected a large area from San Gorgonio pass to the northern Gulf of California.

  13. Geochemistry of a Tertiary sedimentary phosphate deposit: Baja California Sur, Mexico

    Science.gov (United States)

    Piper, D.Z.

    1991-01-01

    The San Gregorio Formation in Baja California Sur, a phosphate-enriched sedimentary unit of late Oligocene to early Miocene age, has been analyzed in two areas (La Purisima and San Hilario) for its chemical composition (major oxides, Cu, Cd, Cr, Co, V, and rare-earth elements - REE) and isotopic composition (??18O and ??13C). A detrital and a marine component were determined from major oxides. The detrital component consists of an unaltered volcanic-ash fraction and a terrigenous clay-silt fraction. The marine component, which accumulated initially as biogenic and hydrogenous material, is now present as opal-A, opal-CT, CaCO3, organic matter, and an authigenic phosphate fraction, mostly pelletal and composed of the carbonate-fluorapatite mineral francolite. The minor elements have been partitioned into these components by assuming a constant composition for the two detrital fractions. The composition of the marine component of minor elements can then be interpreted by assuming that the stoichiometry of the original accumulating organic matter was equal to that of modern plankton. The Cu and Cd contents in the marine component of all rocks require that the seawater-derived fractions of these two metals were supplied to the seafloor solely by organic matter. Enrichments of Cr and V at both sites required an additional marine input. On the basis of their geochemistry in the modern ocean, Cr and V could have precipitated, or been adsorbed, onto settling particles from an O2 minimum zone in which the O2 content was low enough to promote denitrification rather than oxygen respiration. An enrichment of the REE, now within the apatite fraction, resulted from their adsorption onto particulates also in the O2 minimum zone and to the dissolution and alteration of biogenic phases (predominantly silica) within the sediment. Co and Fe2O3 show no enrichment above a detrital contribution. The ??18O-values of apatites from the La Purisima site are heavier than those of apatites

  14. Global Positioning System constraints on fault slip rates in southern California and northern Baja, Mexico

    Science.gov (United States)

    Bennett, Richard A.; Rodi, William; Reilinger, Robert E.

    1996-10-01

    We use Global Positioning System (GPS) estimates of horizontal site velocity to constrain slip rates on faults comprising the Pacific-North America plate boundary in southern California and northern Mexico. We enlist a simple elastic block model to parameterize the distribution and sum of deformation within and across the plate boundary. We estimate a Pacific-North America relative plate motion rate of 49 ± 3 mm/yr (one standard deviation), consistent with NUVEL-1A estimates. We are able to resolve robust slip rate estimates for the southernmost San Andreas, San Jacinto, and Elsinore faults (26 ± 2, 9 ± 2, and 6 ± 2 mm/yr, respectively) and for the Imperial and Cerro Prieto faults (35 ± 2 and 42 ± 1 mm/yr, respectively), accounting for about 86% of the total plate motion. The remaining 14% appears to be accommodated to the west of these fault systems, probably via slip along the San Clemente fault and/or the San Miguel, Vallecitos, Rose Canyon, and Newport-Inglewood fault systems. These results are highly consistent with paleoseismic estimates for slip rates implying that off-fault strain accumulation within the deforming zone of the plate boundary is largely elastic. We estimate that the seismically quiescent, southernmost San Andreas fault has incurred about 8.2 m of slip deficit over the last few hundred years, presumably to be recovered during a future large earthquake.

  15. Comparative analysis of the reproductive strategy of lion's paw scallop Nodipecten subnodosus in Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Marco A Angel-Dapa

    2015-07-01

    Full Text Available The reproductive strategy of lion's paw scallop Nodipecten subnodosus was evaluated in a culturing system in Bahía Tortugas, Baja California Sur, Mexico during an annual cycle, comparing its response with data previously reported at other localities. High frequencies of ripe gonads throughout the year indicate that reproduction was continuous, with two main ripening/spawning events: July-September and December-March. A continuous breeding is also reported for the species in Bahía Magdalena, Bahía Juncalito, and Bahía de Los Angeles. These eutrophic areas are Biological Active Centers where gametogenesis appears to be regulated by the energy taken from recently ingested food following an opportunistic strategy. However, the digestive gland index decreased and the muscle indices increased during one of the breeding peaks, suggesting that some stored reserves are also used to sustain gametogenesis (conservative strategy partially. High incidences of atretic oocytes are likely associated with atypical daily variations in water temperature from May through September (12 to 33°C, or with stressful conditions in the culturing system in summer. Despite this, the culturing system set in Bahía Tortugas appears beneficial for a continuous reproduction of N. subnodosus.

  16. Late cretaceous foraminifera, paleoenvironments, and paleoceanography of the rosario formation, San Antonio del Mar, Baja California, Mexico

    Science.gov (United States)

    Maestas, Y.; MacLeod, K.G.; Douglas, R.; Self-Trail, J.; Ward, P.D.

    2003-01-01

    The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-???40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield ??18OV-PDB values from -2.27%, to -2.82%, corresponding to salinity-corrected paleotemperature estimates of 26-30??C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from ??18O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleodepths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ???1??? positive shift in benthic ??O18, suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

  17. Geodetic studies in Baja California, Mexico, and the evaluation of short-range data from 1974 to 1982

    Science.gov (United States)

    Darby, Desmond; Gonzalez, J. Javier; Lesage, Philippe

    1984-04-01

    The short-range geodetic data from northern Baja California, Mexico, for the period 1974-1982 are carefully analyzed. These data contribute to an understanding of the complex pattern of faulting associated with the Pacific-North American plate boundary in this region. Survey precisions are evaluated and significant systematic errors are found to exist. A technique of studying a scale-free displacement solution is developed as an aid to interpreting the data. We conclude that (1) the motion on the San Miguel-Vallecitos fault system is presently in a right-lateral sense and at a level that warrants trilateration surveys at least annually, (2) present geodetic data permit no statement about movement on the Agua Bianca fault, and (3) the mesa, whose flank delineates the Cerro Prieto fault in the Valle de Mexicali, lies in a zone which has undergone significant horizontal areal compression, at a rate of 14±5 ppm/yr, in addition to a right-lateral tensor shear at a rate of 4±1 ppm/yr, oriented N(;33°±9°)W, between 1980 and 1982.

  18. Stress orientation and anisotropy based on shear-wave splitting observations in the Cerro Prieto fault area, Baja California, Mexico

    Science.gov (United States)

    Zúñiga, F. R.; Castro, R. R.; Domínguez, T.

    1995-03-01

    Digital seismograms continuously recorded from 1988 to 1992 by two stations of the RESNOM seismic network in northern Baja California, Mexico, were used to search for probable shear-wave anisotropic characteristics in the region of the Cerro Prieto fault. Shear-wave splitting was identified in many of the three-component records analyzed. We measured the polarization direction of the leading S wave inside the S-wave window as well as the delay times between fast and slow phases on those records displaying shear-wave splitting. For station CPX, which is nearest the Imperial Valley region to the north, the preferred polarization direction found in this study (azimuth 180°±10°) coincides with the direction of the regional maximum compressive stress determined for the region. This polarization direction can be interpreted in terms of the “Extensive Dilatancy Anisotropy” model as the effect of vertical parallel aligned cracks. The preferred polarization direction measured at LMX, however, gives an azimuth of 45°±5°. Thus, it appears that faults and fractures aligned oblique to the main tectonic trend have a greater influence on the anisotropic characteristics of the crust south of Cerro Prieto volcano than that of the regional stress field. Time delays between slow and fast S waves observed at CPX appear constant from 1988 to 1992 while delays measured at LMX for the same interval indicate a small increase with time which cannot be attributed to azimuthal variations of paths.

  19. Potential toxicity of chemical elements in beach sediments near Santa Rosalía copper mine, Baja California Peninsula, Mexico

    Science.gov (United States)

    Jonathan, M. P.; Shumilin, E.; Rodríguez-Figueroa, G. M.; Rodriguez-Espinosa, P. F.; Sujitha, S. B.

    2016-10-01

    A total of 17 beach sediment samples were analyzed for the determination of thirty-one chemical elements to generate a geochemical data set from the Santa Rosalía mining area in the State of Baja California Sur (south), Mexico. Results indicate that the beach sediments were enriched in Cu, Zn, Co, Pb, Cd (3856, 2599, 635, 236, 240 mg kg-1, respectively) and in Mn (2.01%) due to a century of mining and smelting activities. Comparison of these concentration with ecotoxicological sediment quality criteria (ERL, ERM, LEL, SEL) indicated the values of As, Cd, Co, Cr, Cu, Ni, Pb, Sr, Zn and Mn were higher than the permissible limits. Average values of the calculated geoaccumulation index (Igeo) suggest that the key elements such as Mn, Ba, Cd, Co, Mo, Pb, Sr, Zn are categorized in class 4 to 6 encompassing the strongly polluted to extremely polluted groups. The association and enrichment of the above elements are also well supported statistically (factor analysis) which points to the role of Fe-Mn oxides as the main scavengers for retaining these chemical elements.

  20. Community Liaison as Factor for Image and Positioning of the Autonomous University of Baja California, Mexico, in the Social and Productive Context

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    Víctor Manuel Alcántar Enríquez

    2009-05-01

    Full Text Available This study presents the results of an extensive research on the society’s perceptions of the activities the Autonomous University of Baja California (UABC, for its acronym in Spanish Universidad Autónoma de Baja California develops in Mexico. This non-experimental research uses an explorative-descriptive methodology, with a transactional research design based on a holistic method and an illuminative evaluation, which analyzes the institutional positioning of UABC in several social sectors, as well as its determining factors. Results support the hypothesis that liaison activities have a significant effect on the regional positioning of the UABC as a higher education institution. The results also helped to identify weaknesses and opportunities that could direct future institutional efforts. In addition, this study provides new elements on liaison, institutional image, and positioning, as well as a conceptual model that involves these variables.

  1. Bimodal Distribution of Risk for Childhood Obesity in Urban Baja California, Mexico

    OpenAIRE

    Wojcicki, Janet M.; Jimenez-Cruz, Arturo; Bacardi-Gascon, Montserrat; Schwartz, Norah; Heyman, Melvin B.

    2012-01-01

    In Mexico, higher socioeconomic status (SES) has been found to be associated with increased risk for obesity in children. Within developed urban areas, however, there may be increased risk among lower SES children. Students in grades 4–6 from five public schools in Tijuana and Tecate, Mexico, were interviewed and weight, height and waist circumference (WC) measurements were taken. Interviews consisted of questions on food frequency, food insecurity, acculturation, physical activity and lifest...

  2. Red de mercadeo y rentabilidad de flor de corte en el Valle de Mexicali, Baja California, México Marketing network and profitability of cut flower for Mexicali Valley, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Blancka Yesenia Samaniego-Gámez

    2012-06-01

    during 2004 with more than 122 million pesos, considering flower seed and cut flower production. Most of cut flowers produced in state of Baja California Norte is for export market, by this reason local market means an opportunity for introducing quality products at market prices from national companies. Mexicali city, by being near USA and together with its population economic wealth thanks to profitability of cotton and orchards production in Mexicali Valley, is one or the main producer region in the country. By this reason and thanks to great amount of flower shops located in the region the aim of describing marketing network and profitability for cut flower in Mexicali Valley is proposed. Market study and diagnose to make FODA analysis were developed, defining strategies in order to seize economic potential. Actual distribution networks and marketing system consist in moving cut flowers from production centers, Córdoba, Veracruz and Coatepec de Harinas district, state of Mexico, up to Mexicali Valley, Baja California, keeping quality and optimum vase life for final customer, also proper planning for production chain due not covered demand along year it is required, the population has economical potential and tradition to give flowers guaranteeing good profitability. Roses (Rosa gigantea and R. chinensis L., asian lilies (Lilium spp., chrysanthemum [Dendranthema x grandiflorum (Ramat Kitamura c. v. Polaris White], carnation (Dianthus caryophyllus, gerbera (Gerbera jamesonii H. Bolux ex Hook F. and oriental lilies (Lilium spp. are species with more consumers' interest.

  3. Boron and strontium isotope compositions of groundwater from the La Paz arid coastal aquifer, Baja California Sur, Mexico

    Science.gov (United States)

    Mahlknecht, Jürgen; Rosner, Martin; Meixner, Anette

    2016-04-01

    In groundwater studies boron and strontium isotopic compositions can be used to identify natural and anthropogenic sources as well as processes related to groundwater recharge, flow and mixing. The La Paz arid costal aquifer in Baja California Sur, Mexico, is the most important source of drinking and irrigation water for La Paz area and suffers from anthropogenic contamination and intensive exploitation of the aquifer causing seawater intrusion and general groundwater abatement. The relatively un-radiogenic 87Sr/86Sr isotope ratios of the La Paz groundwater range in a narrow field between 0.7054 and 0.7062. In contrast to strontium the boron isotope composition displays a large variability between +27 and +55 permil d11B. The relatively low 87Sr/86Sr ratios of the La Paz groundwater highlight a significant contribution of strontium derived from local terrestrial sediments and igneous rocks with known 87Sr/86Sr ratios between 0.705 and 0.7035. The large variability of d11B values indicate that multiple sources and processes determine the boron isotope composition of La Paz groundwater. Rainwater (high d11B), seawater (~+40 permil) due to seawater intrusions, wastewater (low to medium d11B) and boron derived from the local geology (low to medium d11B) explain most of the observed groundwater d11B variability. However, d11B values higher than modern seawater point to significant boron isotope fractionation by preferential absorption of 10B onto clay minerals during the evolution of some groundwater samples. Due to low boron concentrations in rainwater a significant contribution of 11B-rich rainwater (>+40 permil) on the La Paz groundwater is unlikely.

  4. Application of MODIS-ASTER (MASTER) simulator data to geological mapping of young volcanic regions in Baja California, Mexico

    Science.gov (United States)

    Dmochowski, Jane Ellen

    Visible, near infrared, short-wave infrared, and thermal infrared multi-channel remote sensing data, MODIS-ASTER (MASTER), are used to extract geologic information from two volcanic regions in Baja California, Mexico: Tres Virgenes-La Reforma Volcanic Region and the volcanic island of Isla San Luis. The visible and near infrared and short-wave infrared data were atmospherically corrected and classified. The resulting classification roughly delineates surfaces that vary in their secondary minerals. Attempts to identify these minerals using ENVI's Spectral Analyst(TM) were moderately successful. The analysis of the thermal infrared data utilizes the shift to longer wavelengths in the Reststrahlen band as the mineralogy changes from felsic to mafic to translate the data into values of weight percent SiO2. The results indicate that the general approach tends to underestimate the weight percent SiO2 in the image. This discrepancy is removed with a "site calibration," which provides good results in the calculated weight percent SiO2 with errors of a few percent. However, errors become larger with rugged topography or low solar angle at the time of image acquisition. Analysis of bathymetric data around Isla San Luis, and consideration of the island's alignment with the Ballenas transform fault zone to the south and volcanic seamounts nearby, suggest Isla San Luis is potentially volcanically active and could be the product of a "leaky" transform fault. The results from the image analysis in the Tres Virgenes-La Reforma Volcanic Region show the La Reforma and El Aguajito volcanic centers to be bimodal in composition and verify the most recent volcanism in the Tres Virgenes region to be basaltic-andesite. The results of fieldwork and image analysis indicate that the volcanic products of the central dome of La Reforma are likely a sequence of welded ash flow tuffs and lavas of varied composition, evidence of its origin as a caldera.

  5. Bioaccumulation and biomagnification of total mercury in four exploited shark species in the Baja California Peninsula, Mexico

    OpenAIRE

    Maz-Courrau, A.; López-Vera, C; Galván Magaña, Felipe; Escobar-Sánchez, O.; Rosíles-Martínez, R; Sanjuán-Muñoz, A.

    2012-01-01

    The present study determined the average Mercury bioaccumulation in the muscle tissue of four shark species (Carcharhinus falciformis, Prionace glauca, Sphyrna zygaena and Isurus oxyrinchus) captured in the Baja California Peninsula. We also evaluated biomagnification of some prey consumed by sharks. All sharks’ species had mercury levels over the limit specified by the Mexican government for human consumption. Blue shark (P. glauca) presented highest mercury values (1.96 ± 1.48 lg/g Hg d.w.)...

  6. Submarine Neotectonic Investigations of the Bahia Soledad Fault, off Northern Baja California Near the US - Mexico Border

    Science.gov (United States)

    Anderson, K.; Lundsten, E. M.; Paull, C. K.; Caress, D. W.; Thomas, H. J.; Maier, K. L.; McGann, M.; Herguera, J. C.; Gwiazda, R.; Arregui, S.; Barrientos, L. A.

    2015-12-01

    The Monterey Bay Aquarium Research Institute (MBARI) conducted detailed surveys at selected sites on the seafloor along the Bahia Soledad Fault offshore of Northern Baja California, Mexico, during a two-ship expedition in the spring of 2015. The Bahia Soledad Fault is a NNW-trending strike-slip fault that is likely continuous with the San Diego Trough Fault offshore of San Diego, California. Constraining the style of deformation, continuity, and slip rate along this fault system is critical to characterizing the seismic hazards to the adjacent coastal areas extending from Los Angeles to Ensenada. Detailed morphologic surveys were conducted using an autonomous underwater vehicle (AUV) to provide ultra high-resolution multibeam bathymetry (vertical precision of 0.15 m and horizontal resolution of 1.0 m). The AUV also carried a 2-10 kHz chirp sub-bottom profiler and an Edgetech 110kHz and 410kHz sidescan. The two sites along the Bahia Soledad Fault each run ~6 km along the fault with ~1.8 km wide footprint. The resulting bathymetry shows these fault zones are marked with distinct lineations that are flanked by ~1 km long elongated ridges and depressions which are interpreted to be transpressional pop-up structures and transtensional pull-apart basins up to 100 m of relief. Offset seismic reflectors that extend to near the seafloor confirm that these lineations are fault scarps. The detailed bathymetric maps and sub-bottom profiles were used to locate key sites where deformed stratigraphic horizons along the fault are within 1.5 m of the seafloor. These areas were sampled using a remotely operated vehicle (ROV) equipped with a vibracoring system capable of collecting precisely located cores that are up to 1.5 m long. The coupled use of multibeam imagery and surgically-collected stratigraphic samples will enable to constrain the frequency and timing of recent movements on this fault which will be useful to incorporated into future seismic hazard assessment.

  7. Composición del aceite esencial de Tagetes lacera, planta endémica de Baja California Sur, México Composition of essential oil of Tagetes lacera, endemic plant from Baja California Sur, Mexico

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    Francisco Díaz-Cedillo

    2012-06-01

    Full Text Available Es escasa la información sobre la biología y química de Tagetes lacera Brand. (Asteraceae, especie endémica de Baja California Sur (BCS, México, que por su porte alto y presencia de aroma es una fuente de aceites esenciales útil para el control de plagas y enfermedades de cultivos agrícolas. A partir de partes aéreas de plantas en floración de T. lacera recolectadas en la sierra de la Laguna, BCS se obtuvo aceite esencial mediante hidrodestilación. Por medio del procedimiento de análisis CG-EM, se identificaron 6 compuestos principales: E-tagetona (26.2%, crisantenona (24.8%, verbenona (22.1%, α-thujeno (20.5%, β-pineno (3.1% y α-pineno (1.9%.It is scarce the background on the biology and chemistry of Tagetes lacera Brand. (Asteraceae, an endemic species from Baja California Sur (BCS, Mexico that considering its plant high and odor is an essential oil source to obtain biopesticides. From aerial parts of plants fully flowered of T. lacera picked in Sierra de la Laguna, BCS, essential oil was obtained by hydrodistillation. Using GC-MS analysis, 6 major compounds were identified: E-tagetone (26.2%, chrysanthenone (24.8%, verbenone (22.1%, α-thujene (20.5%, β-pinene (3.1%, α-pinene (1.9%.

  8. Validation of the ISAAC Standardized Questionnaire Used by Schoolchildren from Mexicali, Baja California, Mexico

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    Karla Gorozave-Car

    2013-01-01

    Full Text Available Background. In Mexico, several studies have been conducted under the ISAAC methodology; nevertheless, no validation studies of the ISAAC questionnaire based on objective clinical testing in our country have been published. Aims of the Study. To validate the ISAAC questionnaire, used in a study of prevalence of allergic diseases, based on medical, respiratory, and allergic evaluations of schoolchildren being 11 to 16 years old in Mexicali, Mexico. Material and Methods. We conducted a cross-sectional study to validate the ISAAC questionnaire through the generation of an index (considered as gold standard using pre- and postbronchodilator spirometry test, exhaled nitric oxide measurements, and atopic evaluations. 114 schoolchildren were included (23 asthmatics with respiratory symptoms and 91 nonasthmatics without respiratory symptoms and we evaluated the sensitivity, specificity, and positive and negative predictive value of the questionnaire using discriminant analysis. Results. We observed sensitivity of 35.2% and specificity of 93.3% and the positive and negative predictive values were 82.6% and 61.5%, respectively. Conclusions. Our findings indicate that the ISAAC Mexican version questionnaire was less sensitive and more specific when compared to the gold standard; however, it is adequate and able to discriminate children with and without asthma and a useful tool to use in epidemiological studies.

  9. Geochemical characteristics of water from the reservoir of the hydrothermal system of Las Tres Virgenes, Baja California Sur, Mexico; Caracteristicas geoquimicas de las aguas del reservorio del sistema hidrotermal actual de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonalez Partida, Eduardo [Universidad Nacional Autonoma de Mexico (Mexico); Tello Hinojosa, Enrique [Comision Federal de Electricidad (Mexico); Pal Verma, Mahendra [Instituto de Investigaciones Electricas (Mexico)

    2001-03-01

    The Las Tres Virgenes geothermal field is a liquid dominated system. The separated produced by the wells are sodium-chloride type, which is a characteristic of totally equilibrated geothermal brine. The temperature of water-rock interaction in the reservoir is 280 Celsius degrees. the chemical composition of gases corresponds to the one expected in a geothermal environment. The CO{sub 2} is the predominating gas and it is superior in 90% in weight to the total of existing gases. The gas contents is less than 1% in weight, in the case of the wells LV-1 and LV-3. It is also possible to conclude that the gases are in equilibrium with the liquid phase at a temperature of 280 Celsius degrees. With respect to water quality, it is saline, from high to very high and the contents of exchangeable sodium is also very high, resulting in waters not fit for agricultural usage. [Spanish] El yacimiento geotermico de Las Tres Virgenes, en Baja California Sur, Mexico, es un sistema de liquido dominante, en donde el agua separada producida por los pozos presenta un caracter clorurado-sodico caracteristico de una salmuera de origen geotermico totalmente equilibrada. El sistema agua-roca se encuentra en equilibrio a una temperatura de 280 grados centigrados , dicha temperatura son congruentes con las estimadas para las fases gaseosas y liquidas. La composicion quimica de los gases corresponde a la esperada en un ambiente geotermico. El CO{sub 2} es el predominante y es superior a 90% en peso del total de los gases presentes. El contenido de gas es menor de 1% en peso en el caso de los pozos LV-1 y LV-3. Tambien se puede concluir que los gases estan en equilibrio en las fases liquidas a una temperatura de 280 grados centigrados. Con respecto a la calidad del agua, presenta una salinidad de alta a muy alta y el contenido de sodio intercambiable tambien es muy alto, por lo que dichas aguas no son muy aptas para el cultivo.

  10. Comparison of enterovirus and adenovirus concentration and enumeration methods in seawater from Southern California, USA and Baja Malibu, Mexico.

    Science.gov (United States)

    Sassoubre, Lauren M; Love, David C; Silverman, Andrea I; Nelson, Kara L; Boehm, Alexandria B

    2012-09-01

    Despite being important etiological agents of waterborne illness, the sources, transport and decay of human viruses in recreational waters are not well understood. This study examines enterovirus and adenovirus concentrations in coastal water samples collected from four beaches impacted by microbial pollution: (1) Malibu Lagoon, Malibu; (2) Tijuana River, Imperial Beach; (3) Baja Malibu, Baja California; and (4) Punta Bandera, Baja California. Water samples were concentrated using a flocculation-based skim milk method and dead-end membrane filtration (MF). Viruses were enumerated using cell culture infectivity assays and reverse transcription quantitative polymerase chain reaction (RT-QPCR). Across concentration and quantification methods, enteroviruses were detected more often than adenoviruses. For both viruses, MF followed by (RT)QPCR yielded higher concentrations than skim milk flocculation followed by (RT)QPCR or cell culture assays. Samples concentrated by skim milk flocculation and enumerated by (RT)QPCR agreed more closely with concentrations enumerated by cell culture assays than MF followed by (RT)QPCR. The detection of viruses by MF and (RT)QPCR was positively correlated with the presence of infectious viruses. Further research is needed to determine if detection of viruses by rapid methods such as (RT)QPCR can be a useful water quality monitoring tool to assess health risks in recreational waters.

  11. Perros ferales en la isla de Cedros, Baja California, México: una posible amenaza para los pinnípedos Feral dogs at Isla de Cedros, Baja California, Mexico: a possible threat for pinnipeds

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    María Concepción García-Aguilar

    2012-09-01

    Full Text Available La presencia de perros ferales (Canis lupus familiaris en la isla de Cedros, Baja California, México, fue documentada hace más de 15 años. En el verano de 2009 e invierno 2009/2010, se realizaron 2 campañas de muestreo en la costa noreste de la isla para evaluar los hábitos alimentarios de los perros en las cercanías de las zonas de reproducción y descanso del lobo marino de California (Zalophus californianus y del elefante marino del norte (Mirounga angustirostris. Los mamíferos constituyeron el grupo consumido más importante en la alimentación de los perros (85.4%. Los resultados de este estudio muestran que en la costa noreste de la isla de Cedros los perros se alimentan de pinnípedos: el elefante marino fue la especie que más se consumió, con el mayor porcentaje en ambas temporadas (43.3% en verano y 51.9% en invierno; el lobo marino, fue la segunda durante el verano (23.3%, aunque su porcentaje disminuyó en el invierno (5.8%. Además del potencial impacto que el consumo por los perros pueda tener sobre las poblaciones de los pinnípedos, una amenaza adicional es la posible transmisión de los patógenos caninos, con serias consecuencias epizoóticas.The presence of feral dogs (Canis lupus familiaris in Isla de Cedros, Baja California, Mexico, has been documented for over 15 years. In the summer of2009 and the winter of 2009/2010, 2 sampling surveys were conducted in the northeast coastal portion of the island to assess the diet of feral dogs in the vicinity of hauled out California sea lions (Zalophus californianus and northern elephant seals (Mirounga angustirostris. Mammals were the most important prey group in the diet of dogs (85.4%. Our results show that in the northeast coast of Isla de Cedros, feral dogs feed on pinnipeds: the elephant seal was the most important prey in both seasons (43.3% in summer and 51.9% in winter, followed by the sea lion as the second most important prey during the summer (23.3%, while its

  12. Bimodal distribution of risk for childhood obesity in urban Baja California, Mexico.

    Science.gov (United States)

    Wojcicki, Janet M; Jimenez-Cruz, Arturo; Bacardi-Gascon, Montserrat; Schwartz, Norah; Heyman, Melvin B

    2012-08-01

    In Mexico, higher socioeconomic status (SES) has been found to be associated with increased risk for obesity in children. Within developed urban areas, however, there may be increased risk among lower SES children. Students in grades 4-6 from five public schools in Tijuana and Tecate, Mexico, were interviewed and weight, height and waist circumference (WC) measurements were taken. Interviews consisted of questions on food frequency, food insecurity, acculturation, physical activity and lifestyle practices. Multivariate logistic models were used to assess risk factors for obesity (having a body mass index [BMI] ≥95th percentile) and abdominal obesity (a WC >90th percentile) using Stata 11.0. Five hundred and ninety students were enrolled; 43.7% were overweight or obese, and 24.3% were obese and 20.2% had abdominal obesity. Independent risk factors for obesity included watching TV in English (odds ratio [OR] 1.60, 95% confidence interval [CI] 1.06-2.41) and perceived child food insecurity (OR 1.57, 95% CI 1.05-2.36). Decreased risk for obesity was associated with female sex (OR 0.64, 95% CI 0.43-0.96), as was regular multivitamin use (OR 0.63, 95% CI 0.42-0.94). Risk obesity was also decreased with increased taco consumption (≥1×/week; OR 0.64, 95% CI 0.43-0.96). Independent risk factors for abdominal obesity included playing video games ≥1×/week (OR 1.18, 95% CI 1.11-2.96) and older age group (10-11 years, OR 2.47, 95% CI 1.29-4.73 and ≥12 years, OR 2.21, 95% CI 1.09-4.49). Increased consumption of tacos was also associated with decreased risk for abdominal obesity (≥1×/week; OR 0.56, 95% CI 0.40-1.00). We found a bimodal distribution for risk of obesity and abdominal obesity in school aged children on the Mexican border with the United States. Increased risk for obesity and abdominal obesity were associated with factors indicative of lower and higher SES including watching TV in English, increased video game playing and perceived food insecurity

  13. Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico.

    Science.gov (United States)

    Schweers, Tanja; Wolff, Matthias; Koch, Volker; Duarte, Francisco Sinsel

    2006-09-01

    The population dynamics of an intertidal population of Megapitaria squalida was studied from September 2002 to February 2003 in Bahia Magdalena, Mexico. To obtain information about the artisanal and recreational fishery of M. squalida, local fishermen at different parts of the bay were interviewed. Clam densities were determined at one unexploited and two exploited sites along perpendicular transects from the shore line. Average clam density was 2.01+/-1.41 ind/m2, densities did not differ significantly between the three sampling sites. The length-total mass relation was Mtot = 0.0001*SL3.1644 (r2 = 0.9804, n = 92) and the length-tissue mass relation was Mtis = 0.0002*SL2.7144 (r2 = 0.945, n = 92). Von Bertalanffy-growth parameters were determined using marked individuals. Strong interindividual and also seasonal differences in growth were observed. Average annual values were: K = 0.655, Linfinity = 83 mm. Since M. squalida can reach a shell length of more than 135 mm in deeper waters, it is necessary to consider intertidal and subtidal populations separately. Average total mortality (Z) was 1.61 y(-1). No fishing mortality was calculated because total mortality Z at the unexploited control site was higher than Z at the exploited sites. It appears that M. squalida migrates into deeper water with increasing shell length, as average shell length increased at lower tidal levels and marked specimens showed a clear migration towards deeper waters. As yet no overexploitation could be found in the study area.

  14. Subsidence monitoring with geotechnical instruments in the Mexicali Valley, Baja California, Mexico

    Science.gov (United States)

    Glowacka, E.; Sarychikhina, O.; Márquez Ramírez, V. H.; Robles, B.; Nava, F. A.; Farfán, F.; García Arthur, M. A.

    2015-11-01

    The Mexicali Valley (northwestern Mexico), situated in the southern part of the San Andreas fault system, is an area with high tectonic deformation, recent volcanism, and active seismicity. Since 1973, fluid extraction, from the 1500-3000 m depth range, at the Cerro Prieto Geothermal Field (CPGF), has influenced deformation in the Mexicali Valley area, accelerating the subsidence and causing slip along the traces of tectonic faults that limit the subsidence area. Detailed field mapping done since 1989 (González et al., 1998; Glowacka et al., 2005; Suárez-Vidal et al., 2008) in the vicinity of the CPGF shows that many subsidence induced fractures, fissures, collapse features, small grabens, and fresh scarps are related to the known tectonic faults. Subsidence and fault rupture are causing damage to infrastructure, such as roads, railroad tracks, irrigation channels, and agricultural fields. Since 1996, geotechnical instruments installed by CICESE (Centro de Investigación Ciéntifica y de Educación Superior de Ensenada, B.C.) have operated in the Mexicali Valley, for continuous recording of deformation phenomena. Instruments are installed over or very close to the affected faults. To date, the network includes four crackmeters and eight tiltmeters; all instruments have sampling intervals in the 1 to 20 min range. Instrumental records typically show continuous creep, episodic slip events related mainly to the subsidence process, and coseismic slip discontinuities (Glowacka et al., 1999, 2005, 2010; Sarychikhina et al., 2015). The area has also been monitored by levelling surveys every few years and, since the 1990's by studies based on DInSAR data (Carnec and Fabriol, 1999; Hansen, 2001; Sarychikhina et al., 2011). In this work we use data from levelling, DInSAR, and geotechnical instruments records to compare the subsidence caused by anthropogenic activity and/or seismicity with slip recorded by geotechnical instruments, in an attempt to obtain more information

  15. Conceptualization of groundwater flow of a coastal arid aquifer using isotopic and chemical tools: La Paz, Baja California Sur, Mexico

    Science.gov (United States)

    Tamez-Melendez, Carol; Hernández-Antonio, Arturo; Mahlknecht, Jürgen

    2016-04-01

    Groundwater from the La Paz coastal aquifer in Baja California Sur, Mexico, is the main source of drinking water for the local population. Due to its proximity to the coast, sea water intrusion is the main factor of salinization of groundwater. Other geochemical processes also affect the quality of the aquifer threating its vulnerability. Forty-seven samples were analyzed for ion chemistry and isotopes. A hierarchical cluster analysis was performed for a better interpretation resulting in three main groups and proved for geographical correspondence. Deuterium and d18O ranged from -82 to -52.1 and from -11.6 to -7 permil, respectively, showing that the main recharge originates in the Sierra el Novillo, flowing toward SE-NW direction and in accordance to deuterium excess (d) high evaporation effects (d>10‰) are mostly in the middle portion of the study area and in El Centenario due to high kinetic isotope fractioning related to elevated temperatures. Hydrogeochemistry analyses demonstrated salinization mainly due to sea water intrusion and in second instance due water-rock interaction, where enrichment of Na+ (ranges from 35.7 to 1089 mg/L-1) was present in some samples probably due to weathering of silicates and/or cation exchange in soils with Ca2+ (27.7 to 658 mg/L-1) at clay-surfaces. High concentrations of NO3-2 (ranges from 1.4 to 48.8 mg/L-1), Cl- (ranges from 54.4 to 2960 mg/L-1) and Na+ show that anthropogenic input is mainly coming from an agricultural area (El Centenario-Chametla) where heavy groundwater extractions are made for irrigational purposes, lowering the groundwater table up to 10 m and consequently promoting upconing and salinity concentrations (NaCl). Carbon-13 and radiocarbon ranged from -12.3 to -9.1‰ and from 29.5 to 100.4 pmC, respectively. Distribution of ages (up to ~5000 years) indicates two flow trends (E-W and SE-NW).

  16. Frecuencias de grupos sanguíneos e incompatibilidades ABO y RhD, en La Paz, Baja California Sur, México Blood group ABO and RhD frequencies and incompatibilities in La Paz, Baja California Sur, Mexico

    OpenAIRE

    2002-01-01

    Objetivo. Determinar las frecuencias génicas y de fenotipo, y predecir el riesgo de incompatibilidad y aloinmunización materna en la población de La Paz, Baja California Sur, México. Material y métodos. Estudio descriptivo en el que se evaluaron 1 809 disponentes sanguíneos altruistas que acudieron en 1998 al Hospital General de Zona, del Instituto Mexicano del Seguro Social en La Paz, Baja California Sur, México, tipificados por aglutinación en tubo. Las frecuencias génicas fueron estimadas ...

  17. The vascular flora and floristic relationships of the Sierra de La Giganta in Baja California Sur, Mexico La flora vascular y las relaciones florísticas de la sierra de La Giganta de Baja California Sur, México

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    José Luis León de la Luz

    2008-06-01

    Full Text Available The Sierra de La Giganta is a semi-arid region in the southern part of the Baja California peninsula of Mexico. Traditionally, this area has been excluded as a sector of the Sonoran Desert and has been more often lumped with the dry-tropical Cape Region of southern Baja California peninsula, but this classical concept of the vegetation has not previously been analyzed using formal documentation. In the middle of the last century, Annetta Carter, a botanist from the University of California, began explorations in the Sierra de La Giganta that lasted 24 years, she collected 1 550 specimens and described several new species from this area, but she never published an integrated study of the flora. Our objectives, having developed extensive collections in the same area over the past years, are to provide a comprehensive species list and description of the vegetation of this mountain range. We found a flora of 729 taxa, poorly represented in tree life-forms (3.1%, a moderate level (4.4% of endemism, and the dominance of plants in the sampling plots is composed mainly for legume trees and shrubs. Additionally, using a biogeographical approach, we compare our list with other known lists of plants from 5 areas, 3 in the Cape Region, 1 in the Sonoran Desert, and other in the thornscrub area of NW Mexico. We conclude that the La Giganta flora has a mixed composition, primarily made up of plants shared with the lowlands of the southern Cape Region, but also share an important proportion of the flora with the desert mountains of the central peninsula and some with the Sonoran desertscrub of mainland Mexico. Consequently we support that the La Giganta flora is part of a floristic continuum along the volcanic mountains of the southern peninsula that eventually could be considered a new eco-region in the same peninsular land.La sierra de La Giganta se localiza en el estado de Baja California Sur, México, en una región semi-árida. Tradicionalmente, esta

  18. Low-temperature thermochronology of northern Baja California, Mexico: Decoupled slip-exhumation gradients and delayed onset of oblique rifting across the Gulf of California

    Science.gov (United States)

    Seiler, Christian; Fletcher, John M.; Kohn, Barry P.; Gleadow, Andrew J. W.; Raza, Asaf

    2011-06-01

    The northern Gulf Extensional Province displays key structural relationships that characterize the magnitude, direction, and timing of Neogene rift-related transtension during the opening of the Gulf of California. Apatite fission track and (U-Th)/He thermochronology from the Sierra San Felipe document moderate cooling (4°C/Myr-7°C/Myr) during the early Paleogene associated with progressive unroofing caused by erosional downwearing of the ancestral Peninsular Ranges. Beginning at ˜45-35 Ma, a period of tectonic quiescence with low cooling rates (≤1°C/Myr) marks the development of a regional Oligocene-Miocene peneplain. Rift-related exhumation began at ˜9-7 Ma and attains ˜2.5 km in the hinges of two antiformal megamullions. Decoupling between exhumation and finite displacement in certain fault segments is explained by vertical deflections associated with extension-perpendicular folding of the fault surfaces. The main faults of the detachment system were active contemporaneously, thus forming a mechanically linked array of large-displacement normal faults in the hanging wall of the Main Gulf Escarpment. The Late Miocene onset of transtension in the Sierra San Felipe suggests that widespread deformation may only have localized in the Gulf Extensional Province between ˜9 and 7 Ma, some ˜3-5 Ma after a major plate reorganization associated with cessation of subduction in the trench to the west. Between ˜12 Ma and ˜9-7 Ma, plate boundary shearing was likely distributed between the continental borderland west of Baja California and the southern Basin and Range province in Mexico.

  19. Variabilidad de la abundancia de zooplancton en Bahía Magdalena Baja California Sur, México (1997-2001 Zooplankton abundance variability in Magdalena Bay, Baja California Sur, Mexico (1997-2001

    Directory of Open Access Journals (Sweden)

    Sergio Hernández-Trujillo

    2010-01-01

    Full Text Available Se analizaron muestras de zooplancton de 16 campañas oceanógraficas, efectuadas en Bahía Magdalena, Baja California Sur, México, entre agosto de 1997 y marzo de 2001. Se identificó un total de 26 grupos taxonómicos, de los cuales los más abundantes y frecuentes fueron copépodos y quetognatos; en 2000-2001 se observó una tendencia a disminuir entre 10 y 20 el número de grupos de zooplancton. La biomasa zooplanctónica y abundancia de copépodos disminuyeron en el periodo de estudio, en contraste con los quetognatos que tuvieron un ligero aumento. Las fluctuaciones de abundancia de zooplancton no estuvieron relacionadas con la concentración de clorofila-α, a diferencia de los máximos de abundancia de zooplancton, que estuvieron asociados a los cambios de la temperatura superficial del mar. El ciclo estacional de la abundancia del zooplancton en Bahía Magdalena, indicó que en invierno el promedió fue mayor de 65.000 ind 100 m-3 , valor que aumentó en primavera a más de 99.000 ind 100 m-3 , se mantuvo en verano alrededor de 100.000 ind 100 m-3 y en otoño descendió rápidamente a casi 40.000 ind 100 m-3.Zooplankton were studied from 16 oceanographic surveys carried out in Magdalena Bay, Baja California Sur, Mexico, between August 1997 and March 2001. Twenty-six taxonomic groups were identified, the most abundant and frequent of which were copepods and chaetognaths. In 2000-2001, the number of zooplankton groups tended to decrease by 10 to 20. Both zooplankton biomass and copepod abundance declined, unlike chaetognaths, which increased slightly. Fluctuations in zooplankton abundance were independent of the chlorophyll-a concentration, whereas the maximum zooplankton abundances were associated with changes in the sea surface temperature. The seasonal zooplankton abundance cycle in Magdalena Bay indicated that, in winter, the averaged was than 65,000 ind 100 m-3 , a value that increased to more than 99,000 ind 100 m-3 in spring

  20. Results and evaluation of the first study of organochlorine contaminants (PCDDs, PCDFs, PCBs and DDTs), heavy metals and metalloids in birds from Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Begona [Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain)]. E-mail: bjimenez@iqog.csic.es; Rodriguez-Estrella, Ricardo [Centro de Investigaciones Biologicas del Noroeste, Mar Bermejo 195, Apdo. Postal 128, La Paz, Baja California Sur (Mexico); Merino, Ruben [Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Gomez, Gema [Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Rivera, Laura [Centro de Investigaciones Biologicas del Noroeste, Mar Bermejo 195, Apdo. Postal 128, La Paz, Baja California Sur (Mexico); Jose Gonzalez, Maria [Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Abad, Esteban [Department of Ecotechnologies, Research and Development Center, CSIC, Jordi Girona, 18-26, 08034 Barcelona (Spain); Rivera, Josep [Department of Ecotechnologies, Research and Development Center, CSIC, Jordi Girona, 18-26, 08034 Barcelona (Spain)

    2005-01-01

    Organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p-p'-DDE), heavy metals (Pb, Cd, Zn, Cu), and arsenic were measured in house sparrows (Passer domesticus) and common ground doves (Columbina passerina) from Baja California Sur, Mexico. Concentrations of PCDD/Fs were low, with 21 pg/g for house sparrows, and 7.7 pg/g for common ground doves. Non-ortho-PCB concentrations in house sparrow and common ground doves were 58 and 254 pg/g, respectively, and are within the highest concentrations reported in species that are in the low levels of food webs. The major differences in organochlorine levels between species were found for ortho-PCBs and DDTs. ortho-PCB levels were higher in the seedeater species, whereas DDT levels were higher in the omnivorous species. Heavy metal levels were far below those associated with negative effects. - Capsule: The first data on contaminants in birds from Baja California is given.

  1. Bioaccumulation and biomagnification of total mercury in four exploited shark species in the Baja California Peninsula, Mexico.

    Science.gov (United States)

    Maz-Courrau, A; López-Vera, C; Galván-Magaña, F; Escobar-Sánchez, O; Rosíles-Martínez, R; Sanjuán-Muñoz, A

    2012-02-01

    The present study determined the average mercury bioaccumulation in the muscle tissue of four shark species (Carcharhinus falciformis, Prionace glauca, Sphyrna zygaena and Isurus oxyrinchus) captured in the Baja California Peninsula. We also evaluated biomagnification of some prey consumed by sharks. All sharks' species had mercury levels over the limit specified by the Mexican government for human consumption. Blue shark (P. glauca) presented highest mercury values (1.96 ± 1.48 μg/g Hg d.w.) and it was the unique specie that showed a negative correlation with mercury content (Rs = -0.035, p = 0.91). Scomber japonicus was the prey with high content of mercury (0.57 ± 0.02 μg/g).

  2. Isópodos litorales y de aguas someras de la bahía de Todos los Santos, Baja California, México Littoral and shallow water isopods from Todos los Santos Bay, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Ernesto Campos

    2008-12-01

    Full Text Available Se presenta una lista de los isópodos de vida libre de la bahía de Todos los Santos con base en recolecciones alocrónicas realizadas entre 1988 y 2005 en el intermareal rocoso, arenoso y limo-arcilloso así como en el sublitoral arenoso hasta una profundidad de 256 m. Se recolectaron 26 especies de las 48 registradas para la Provincia Californiana: 2 Asellota; 7 Cymothoida; 1 Oniscoidea; 7 Sphaeromatidea; 9 Valvifera Las especies más abundantes fueron Excirolana linguifrons (Richardson, 1899, (mesolitoral arenoso, Idotea fewkesi Richardson, 1905 junto con Idotea resecata Stimpson, 1857, (mesolitoral rocoso, Haliophasma geminatum Menzies et Barnard, 1959 (mesolitoral e infralitoral arcilloso asociada al pasto marino Zostera marina Linnaeus y Caecognathia crenulatifrons (Monod, 1926, (sublitoral. Las especies recolectadas se ha registrado en biotopos marinos similares de California, Estados Unidos de América. De las 26 especies encontradas 7 son primeros registros para México: Erichsonella crenulata Menzies, 1950, Exosphaeroma amplicauda (Stimpson 1857, E. octonum (Richardson, 1899, Idarcturus allelomorphus Menzies et Barnard, 1959, Idotea fewkesi, Janiralata davisi Menzies, 1951 y Paracerceis gilliana (Richardson, 1899, extendiendo su distribución sureña hasta la bahía de Todos los Santos.A checklist of the free-living isopods of Todos los Santos Bay, Baja California, is presented on the basis of allochronic collections made between 1988 and 2005 along the rocky, sandy, and muddy intertidal and sandy subtidal to 256 meters deep. We collected 26 of the 48 species known from the Californian province: 2 Asellota; 7 Cymothoida; 1 Oniscoidea; 7 Sphaeromatidea; 9 Valvifera. The most abundant species were Excirolana linguifrons (Richardson, 1899, (sandy mesolitoral, Idotea fewkesi Richardson, 1905 and I. resecata Stimpson 1857, (rocky intertidal, Haliophasma geminatum Menzies and Barnard, 1959, (muddy intertidal and subtidal associated with the

  3. Backscattering and geophysical features of volcanic ridges offshore Santa Rosalia, Baja California Sur, Gulf of California, Mexico

    Science.gov (United States)

    Fabriol, Hubert; Delgado-Argote, Luis A.; Dañobeitia, Juan José; Córdoba, Diego; González, Antonio; García-Abdeslem, Juan; Bartolomé, Rafael; Martín-Atienza, Beatriz; Frias-Camacho, Víctor

    1999-11-01

    Volcanic ridges formed by series of volcanic edifices are identified in the central part of the Gulf of California, between Isla Tortuga and La Reforma Caldera-Santa Rosalı´a region. Isla Tortuga is part of the 40-km-long Tortuga Volcanic Ridge (TVR) that trends almost perpendicular to the spreading center of the Guaymas Basin. The Rosalı´a Volcanic Ridge (RVR), older than TVR, is characterized by volcanic structures oriented towards 310°, following a fracture zone extension and the peninsular slope. It is interpreted that most of the aligned submarine volcanic edifices are developed on continental crust while Isla Tortuga lies on oceanic-like crust of the Guaymas Basin. From a complete Bouguer anomaly map, it is observed that the alignments of gravity highs trending 310° and 290° support the volcanic and subvolcanic origin of the bathymetric highs. Volcanic curvilinear structures, lava flows and mounds were identified from backscattering images around Isla Tortuga and over a 400-m high (Vı´rgenes High), where the TVR and the RVR intersect. A refraction/wide-angle seismic profile crossing perpendicular to the Vı´rgenes High, together with gravity and magnetic data indicate the presence of shallow intrusive bodies presumably of basaltic or andesitic composition. It is inferred that most volcanic edifices along the ridges have similar internal structures. We suggest that the growth of different segments of the ridges have a volcano-tectonic origin. The older RVR lies along the extension of a fracture zone and it probably is associated with Pliocene NE-SW extension.

  4. Strain Localisation at Rift Segment Boundaries: An Example from the Bocana Transfer Zone in Central Baja California, Mexico

    Science.gov (United States)

    Seiler, C.; Gleadow, A. J.; Kohn, B. P.

    2012-12-01

    Rifts are commonly segmented into several hundred kilometre long zones of opposing upper-plate transport direction with boundaries defined by accommodation and transfer zones. A number of such rift segments have been recognized in the northern Gulf of California, a youthful oceanic basin that is currently undergoing the rift-drift transition. However, detailed field studies have so far failed to identify suitable structures that could accommodate the obvious deformation gradients between different rift segments, and the nature of strain transfer at segment boundaries remains enigmatic. The situation is even less clear in central and southern Baja California, where a number of rift segments have been hypothesized but it is unknown whether the intervening segment boundaries facilitate true reversals in the upper-plate transport direction, or whether they simply accommodate differences in the timing, style or magnitude of deformation. The Bocana transfer zone (BTZ) in central Baja California is a linear, WNW-ESE striking structural discontinuity separating two rift segments with different magnitudes and styles of extensional deformation. North of the BTZ, the Libertad fault is part of the Main Gulf Escarpment, which represents the breakaway fault that separates the Gulf of California rift to the east from the relatively stable western portion of the Baja peninsula. The N-striking Libertad escarpment developed during the Late Miocene (~10-8Ma) and exhibits a topographic relief of ca. 1,000m along a strike-length of ca. 50km. Finite displacement decreases from ~1000m in the central fault segment to ~500m further south, where the fault bends SE and merges with the BTZ. In the hanging wall of the Libertad fault, a series of W-tilted horsts are bound along their eastern margins by two moderate-displacement E-dipping normal faults. South of the BTZ, extension was much less than further north, which explains the comparatively subdued relief and generally shallower tilt of

  5. Surface Deformation Associated with Geothermal Fluids Extraction at the Cerro Prieto Geothermal Field, Baja California, Mexico Revealed by DInSAR Technique

    Science.gov (United States)

    Sarychikhina, O.; Glowacka, E.; Mojarro, J.

    2016-08-01

    The Differential Synthetic Aperture Radar Interferometry (DInSAR) is widely used for surface deformation detection and monitoring.In this paper, ERS-1/2, ENVISAT and RADARSAT-2 synthetic aperture radar (SAR) images acquired between 1993 and 2014 were processed to investigate the evolution of surface deformation at the Cerro Prieto geothermal field, Baja California, Mexico. The conventional DInSAR together with the interferogram stacking method was applied. Average LOS (line of sight) displacement velocity maps were generated for different periods: 1993 - 1997, 1998 - 2000, 2004, 2005, 2007, 2009, and 2012 - 2014, revealing that the area corresponding to Cerro Prieto basin presented the important surface deformation (mainly subsidence) during the entire time of investigation. The changes in the surface deformation pattern and rate were identified. These changes have a good correlation in time with the changes of production in the Cerro Prieto geothermal field.

  6. An annotated distributional checklist of exotic freshwater fishes from the Baja California Peninsula, Mexico Lista comentada sobre la distribución de peces dulceacuícolas exóticos de la península de Baja California, México

    OpenAIRE

    Gorgonio Ruiz-Campos; Salvador Contreras-Balderas; Asunción Andreu-Soler; Alejandro Varela-Romero; Ernesto Campos

    2012-01-01

    We documented the distributional status of 27 exotic fish species in the inland waters of the Baja California Peninsula, Mexico, based on voucher specimens collected from 122 sites between 1977 and 2010, and on published records. The species reported here are representatives of genera from the Atlantic drainages of North America (Ictalurus, Ameiurus, Pylodictis, Morone, Lepomis, Pomoxis, Dorosoma, Cyprinella, and Micropterus), Middle America (Poecilia, Gambusia, and Xiphophorus), Eurasia (Cyp...

  7. Perros ferales en la isla de Cedros, Baja California, México: una posible amenaza para los pinnípedos Feral dogs at Isla de Cedros, Baja California, Mexico: a possible threat for pinnipeds

    OpenAIRE

    María Concepción García-Aguilar; Juan Pablo Gallo-Reynoso

    2012-01-01

    La presencia de perros ferales (Canis lupus familiaris) en la isla de Cedros, Baja California, México, fue documentada hace más de 15 años. En el verano de 2009 e invierno 2009/2010, se realizaron 2 campañas de muestreo en la costa noreste de la isla para evaluar los hábitos alimentarios de los perros en las cercanías de las zonas de reproducción y descanso del lobo marino de California (Zalophus californianus) y del elefante marino del norte (Mirounga angustirostris). Los mamíferos constituy...

  8. Evolution of the 2014-2015 sea surface temperature warming in the central west coast of Baja California, Mexico, recorded by remote sensing

    Science.gov (United States)

    Robinson, Carlos J.

    2016-07-01

    Extraordinarily warm sea surface temperatures were present in the California Current System during 2014-2015. In several locations surface waters temperature registered new record high in the recent time series. This study focuses in the evolution of the warming in the southern part of the California Current System (CCS), off the west coast of Baja California, Mexico. Analysis of monthly sea surface temperature (SST), sea level pressure, and wind speed as measured by satellite from January 1988 to December 2015 show that recent warming occurred during two distinct periods. From May 2014 to April 2015, SST warming was related to weak coastal winds not associated to El Niño. During this period occurred the longest sustained record of 15 months of negative wind anomalies in the series. A reduction of wind stress suggests a weakened coastal upwelling, and consequently, cold water not transported into the surface. The second process of warming occurred from September to December 2015, during a strong El Niño condition.

  9. A new species of Ceanothus from northern Baja California

    Science.gov (United States)

    Boyd, Steve; Keeley, Jon E.

    2002-01-01

    Ceanothus bolensis S. Boyd & J. Keeley is a new species in the subgenus Cerastes from northwestern Baja California, Mexico. It is well represented at elevations above 1000 m on Cerro Bola, a basaltic peak approximately 35 km south of the U.S./Mexican border. It is characterized by small, obovate to oblanceolate, cupped, essentially glabrous leaves with sparsely toothed margins, pale blue flowers, and globose fruits lacking horns. Principal components analysis on morphological traits shows it to be distinct from other members of Cerastes which are distributed away from the coast in southern California and Baja California, Mexico. These phenetic comparisons also suggest that Ceanothus otayensis should not be subsumed under C. crassifolius, as treated in the Jepson Manual, but rather should be retained at specific rank as well.

  10. Fluoride, nitrate and water hardness in groundwater supplied to the rural communities of Ensenada County, Baja California, Mexico

    Science.gov (United States)

    Daesslé, L. W.; Ruiz-Montoya, L.; Tobschall, H. J.; Chandrajith, R.; Camacho-Ibar, V. F.; Mendoza-Espinosa, L. G.; Quintanilla-Montoya, A. L.; Lugo-Ibarra, K. C.

    2009-07-01

    The hydrogeochemistry of 26 wells belonging to ten different aquifers in the county of Ensenada, Baja California, is studied. These wells are all used to supply the rural communities in the region, which comprise ~37,000 inhabitants, excluding the city of Ensenada. High total dissolved solids (TDS) concentrations (maximum 7.35 g l-1) indicate that salt is a ubiquitous contaminant in the aquifers due to seawater intrusion. The aquifers that support extensive agriculture activities (Maneadero, San Quintín, San Simón and El Rosario) are characterized by higher N-NO3 concentrations (maximum 20 mg l-1) derived from fertilizers. Fluoride concentrations exceed the 1.5 mg l-1 Mexican official limit in only four wells. The enrichments of F- in the southern aquifers are thought to be associated to water-rock interactions controlled mainly by Na-Ca equilibrium reactions with fluorite, as suggested from high dissolved Na concentrations in these waters. In the northern aquifer of Maneadero, no enrichment of Na is found and a geothermal source for F- is likely. Water is hard to moderately hard, with Ca/Mg ratios >1. Although drinking water directly from the tap is not a common practice in these localities, most sources have concentrations of major ions and TDS that exceed the Mexican official limits.

  11. Late Neogene stratigraphy and tectonic control on facies evolution in the Laguna Salada Basin, northern Baja California, Mexico

    Science.gov (United States)

    Martín-Barajas, A.; Vázquez-Hernández, S.; Carreño, A. L.; Helenes, J.; Suárez-Vidal, F.; Alvarez-Rosales, J.

    2001-10-01

    The Laguna Salada Basin (LSB) in northeastern Baja California records late-Neogene marine incursions in the Salton Trough and progradation of the Colorado River delta. Early subsidence and subsequent tectonic erosion are related to evolution of the Sierra El Mayor detachment fault during late Miocene time (geothermal exploratory well on the eastern margin of LSB. Interfingering fluvial-sandstone deposits and prograding alluvial fanglomerates with coarse debris-flow and rock-avalanche deposits crudely mark the onset of vertical slip along the Laguna Salada fault and rapid uplift of Sierra Cucapa and Sierra El Mayor. Up to 2 km of Quaternary alluvial-fan and lacustrine deposits accumulated along the eastern margin of LSB, whereas lower subsidence rates produced a thinner sedimentary wedge over a ramp-like crystalline basement along the western margin. In early Pleistocene time (˜2-1 Ma), the Laguna Salada became progressively isolated from the Colorado River delta complex, and the Salton Trough by activity on the Elsinore and Laguna Salada fault zones.

  12. Marine diet and tobacco exposure affects mercury concentrations in pregnant women (I from Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Ramón Gaxiola-Robles

    2014-01-01

    Full Text Available Seafood provides essential polyunsaturated fatty acids (PUFA and other nutrients to pregnant women and their fetus(es while a diet rich in finfish can be a major pathway of monomethyl mercury (MeHg+ exposure. We measured total mercury concentration ([THg] in hair samples provided by 75 women in Baja California Sur (BCS to assess its relationship with age, parity, tobacco smoke exposure, and diet based on survey methodologies. Generalized linear models (GLM were used to explain the possible association of the different variables with [THg] in hair. Median [THg] in hair was 1.52 μg g−1, ranging from 0.12 to 24.19 μg g−1 and varied significantly by segment. Approximately 72% (54/75 of those evaluated exceed 1 μg g−1 [THg] and 8% (6/75 exceed 5 μg g−1 [THg] in hair. Although frequency of fish consumption contributed significantly to explaining hair [THg], fish consumption only explained 43% of [THg] in a GLM incorporating tobacco exposure and body mass index. This study establishes possible relationships among multiple potential sources of exposure and other factors related to [THg] in hair of women in the prenatal period. A more detailed examination of other sources of exposure and factors contributing to [THg] is warranted.

  13. Marine diet and tobacco exposure affects mercury concentrations in pregnant women (I) from Baja California Sur, Mexico

    Science.gov (United States)

    Gaxiola-Robles, Ramón; Bentzen, Rebecca; Zenteno-Savín, Tania; Labrada-Martagón, Vanessa; Castellini, J. Margaret; Celis, Alfredo; O’Hara, Todd; Celina Méndez-Rodríguez, Lía

    2017-01-01

    Seafood provides essential polyunsaturated fatty acids (PUFA) and other nutrients to pregnant women and their fetus(es) while a diet rich in finfish can be a major pathway of monomethyl mercury (MeHg+) exposure. We measured total mercury concentration ([THg]) in hair samples provided by 75 women in Baja California Sur (BCS) to assess its relationship with age, parity, tobacco smoke exposure, and diet based on survey methodologies. Generalized linear models (GLM) were used to explain the possible association of the different variables with [THg] in hair. Median [THg] in hair was 1.52 µgg−1, ranging from 0.12 to 24.19 µgg−1 and varied significantly by segment. Approximately 72% (54/75) of those evaluated exceed 1 µgg−1 [THg] and 8% (6/75) exceed 5 µgg−1 [THg] in hair. Although frequency of fish consumption contributed significantly to explaining hair [THg], fish consumption only explained 43% of [THg] in a GLM incorporating tobacco exposure and body mass index. This study establishes possible relationships among multiple potential sources of exposure and other factors related to [THg] in hair of women in the prenatal period. A more detailed examination of other sources of exposure and factors contributing to [THg] is warranted. PMID:28203532

  14. Status of the peregrine falcon in the Rocky Mountains and the southwestern United States, Baja California, and Mexico (south of Texas)

    Science.gov (United States)

    Porter, Ron; Craig, G.R.; Ellis, D.H.; Enderson, J.H.; Hunt, W.G.; Schaeffer, Philip P.; Ehlers, Sharyn M.

    1978-01-01

    About 31 pairs of peregrines still nest north of Mexico, from Idaho and Montana south through West Texas, New Mexico and Arizona. At least thirty-six additional pairs nest in Mexico. Although the nesting sites are occupied, the tissues of the peregrine?s prey species still contain high concentrations of pesticides. The eggs in some Rocky Mountain eyries have shells which are precariously thin and have high residue levels of DDE in their contents. Increasing economic development is encroaching on the peregrine habitat throughout its range in western North America. In Baja California. and Mexico south of Texas this involves increased agricultural activity including use of organochlorine pesticides, increased tourism and increased use of the Gulf of California both for commercial and sport fishing, with their potential disturbance of eyrie sites and reduction of the peregrine?s aquatic feeding prey base. As the fish in the Gulf decrease in number, some of the avian species on which peregrines prey will likewise decrease. This ultimately may effect the peregrine. These factors may have been involved in the demise of the peregrine on Baja California?s Pacific coast. Furthermore, throughout its range, residential, industrial, mining, geothermal, recreational and other types of development and land use practices sometimes destroy habitat essential to the survival of the peregrine. A recent request for the protection of an historical site in California as Critical Habitat under Section 7 of the Endangered Species Act was rejected because peregrines, although observed there, were not known to have produced eggs or young at the site for several decades. With inadequate protection of abandoned, but still suitable, historical eyrie sites, the peregrine may have an insufficient number of eyries to reoccupy in recovery attempts. The lack of present occupancy of a site, without biological evidence that the site is no longer suitable for reoccupancy, is insufficient cause to give

  15. Transformations of Mangrove Forests in Bahia Magdalena, Baja California Sur, Mexico: Two Decade Results Based on Landsat Imageries

    Science.gov (United States)

    Suresh Babu, S.; Abdul Rahaman, S.; Muthushankar, G.; Jonathan, M. P.

    2014-12-01

    Mangrove forests which thrive along the tropical and subtropical regions are the most productive ecosystems in the world with a wide range of ecological and economical services to mankind. With the rapid urbanization across the globe, these forests tend to be destroying at an alarming rate. The area of concern for this study, Bahia Magdalena is very important for the economy of the state as nearly 50% of the artisan fisheries are established in the mangrove zone. Henceforth this study is an attempt for a regional assessment and to accurately quantify the mangroves using LANDSAT imageries for over two decades in Bahia Magdalena, Baja California. Satellite imageries from the year 1986 through 2014 were analysed to assess the prolonged changes taking place in and around the mangrove reserve. Using the estimates of land use/cover for all the years, the spatio - temporal data was validated using ArcGIS software. The results revealed that the spatial extent of mangroves are decreasing until 2005 due to the developmental plans such as tourism, shrimp farming and establishment of industries in this part of the country. During the past 10 years (~ after 2005) there is no much change in the area extent of mangrove reserves due to afforestation and conservation efforts. Thus the unbiased dataset generated may be widely used for an improved understanding of the role of mangrove forests in the socio economic aspects, protection from natural disasters, identify possible areas for conservation, restoration and rehabilitation; and improve estimates of the amount of carbon stored in mangrove vegetation and the associated marine environment. Keywords: Mangroves, LANDSAT, Bahia Magdalena, México.

  16. Sea-surface temperature gradients across blue whale and sea turtle foraging trajectories off the Baja California Peninsula, Mexico

    Science.gov (United States)

    Etnoyer, Peter; Canny, David; Mate, Bruce R.; Morgan, Lance E.; Ortega-Ortiz, Joel G.; Nichols, Wallace J.

    2006-02-01

    Sea-surface temperature (SST) fronts are integral to pelagic ecology in the North Pacific Ocean, so it is necessary to understand their character and distribution, and the way these features influence the behavior of endangered and highly migratory species. Here, telemetry data from sixteen satellite-tagged blue whales ( Balaenoptera musculus) and sea turtles ( Caretta caretta, Chelonia mydas, and Lepidochelys olivacea) are employed to characterize 'biologically relevant' SST fronts off Baja California Sur. High residence times are used to identify presumed foraging areas, and SST gradients are calculated across advanced very high resolution radiometer (AVHRR) images of these regions. The resulting values are compared to classic definitions of SST fronts in the oceanographic literature. We find subtle changes in surface temperature (between 0.01 and 0.10 °C/km) across the foraging trajectories, near the lowest end of the oceanographic scale (between 0.03 and 0.3 °C/km), suggesting that edge-detection algorithms using gradient thresholds >0.10 °C/km may overlook pelagic habitats in tropical waters. We use this information to sensitize our edge-detection algorithm, and to identify persistent concentrations of subtle SST fronts in the Northeast Pacific Ocean between 2002 and 2004. The lower-gradient threshold increases the number of fronts detected, revealing more potential habitats in different places than we find with a higher-gradient threshold. This is the expected result, but it confirms that pelagic habitat can be overlooked, and that the temperature gradient parameter is an important one.

  17. AUV Mapping and ROV Exploration of Los Frailes Submarine Canyon, Cabo Pulmo National Marine Park, Baja California Sur, Mexico

    Science.gov (United States)

    Troni, G.; Caress, D. W.; Graves, D.; Thomas, H. J.; Thompson, D.; Barry, J. P.; Aburto-Oropeza, O.; Johnson, A. F.; Lundsten, L.

    2015-12-01

    Los Frailes submarine canyon is located at the south boundary of the Cabo Pulmo National Marine Park on the southeast tip of the Baja California Peninsula. During the Monterey Bay Aquarium Research Institute (MBARI) 2015 Gulf of California expedition we used an autonomous underwater vehicle (AUV) to map this canyon from 50 m to 450 m depths, and then explored the canyon with a small remotely operated vehicle (ROV). This three day R/V Rachel Carson cruise was a collaboration with the Center for Marine Biodiversity and Conservation at Scripps Institution of Oceanography and the Centro para la Biodiversidad Marina y la Conservación in La Paz. The MBARI AUV D. Allan B. collected high resolution bathymetry, sidescan, and subbottom profiles of Los Frailes submarine canyon and part of the north Cabo Pulmo deep reef. In order to safely generate a 1-m lateral resolution multibeam bathymetry map in the nearshore high relief terrain, the mapping operations consisted of an initial short survey following the 100-m isobath followed by a series of short, incremental AUV missions located on the deep edge of the new AUV bathymetry. The MBARI Mini-ROV was used to explore the submarine canyon within the detailed map created by the MBARI AUV. The Mini-ROV is a 1.2-m-long, 350 kg, 1,500-m-depth-rated ROV designed and constructed by MBARI. It is controlled by six 600-watt thrusters and is equipped with a high-definition video camera and navigation sensors. This small ROV carries less accurate, lower cost navigation sensors than larger vehicles. We implemented new algorithms to localize combining Doppler velocity log sensor data and low-cost MEMS-based inertial sensor data with sporadic ultra-short baseline position measurements to provide a high accuracy position estimation. The navigation performance allowed us to colocate the ROV video imagery with the 1-m resolution bathymetric map of the submarine canyon. Upper Los Frailes Canyon is rugged and, aside from small sand pockets along

  18. Vent fluid chemistry in Bahía Concepción coastal submarine hydrothermal system, Baja California Sur, Mexico

    Science.gov (United States)

    Prol-Ledesma, R. M.; Canet, C.; Torres-Vera, M. A.; Forrest, M. J.; Armienta, M. A.

    2004-10-01

    Shallow submarine hydrothermal activity has been observed in the Bahía Concepción bay, located at the Gulf coast of the Baja California Peninsula, along faults probably related to the extensional tectonics of the Gulf of California region. Diffuse and focused venting of hydrothermal water and gas occurs in the intertidal and shallow subtidal areas down to 15 m along a NW-SE-trending onshore-offshore fault. Temperatures in the fluid discharge area vary from 50 °C at the sea bottom up to 87 °C at a depth of 10 cm in the sediments. Chemical analyses revealed that thermal water is enriched in Ca, As, Hg, Mn, Ba, HCO 3, Li, Sr, B, I, Cs, Fe and Si, and it has lower concentrations of Cl, Na, SO 4 and Br than seawater. The chemical characteristics of the water samples indicate the occurrence of mixing between seawater and a thermal end-member. Stable isotopic oxygen and hydrogen composition of thermal samples plot close to the Local Meteoric Water Line on a mixing trend between a thermal end-member and seawater. The composition of the thermal end-member was calculated from the chemistry of the submarine samples data by assuming a negligible amount of Mg for the thermal end-member. The results of the mixing model based on the chemical and isotopic composition indicate a maximum of 40% of the thermal end-member in the submarine vent fluid. Chemical geothermometers (Na/Li, Na-K-Ca and Si) were applied to the thermal end-member concentration and indicate a reservoir temperature of approximately 200 °C. The application of K-Mg and Na/Li geothermometers for vent fluids points to a shallow equilibrium temperature of about 120 °C. Results were integrated in a hydrogeological conceptual model that describes formation of thermal fluids by infiltration and subsequent heating of meteoric water. Vent fluid is generated by further mixing with seawater.

  19. Gobernanza de la infraestructura y sustentabilidad ecosistémica en Punta Colonet, Baja California, México Governance of infrastructure and ecosystem sustainability in Punta Colonet, Baja California state, Mexico

    Directory of Open Access Journals (Sweden)

    Ricardo V. Santes Álvarez

    2013-03-01

    Full Text Available Este artículo estudia la problemática sociopolítica y ambiental de la probable construcción del puerto de Punta Colonet, en Baja California. Anunciado como el principal proyecto de infraestructura del gobierno federal, su concepción olvida objetivos de conservación de recursos e intereses locales. El surgimiento de la dualidad entre "desarrollistas" y "conservacionistas" solamente enmascara una preocupación mayor: la fortaleza institucional. Consecuentemente, el análisis se sustenta en términos de normativas, actuación gubernamental y participación social. Asimismo, se presenta una propuesta de equilibrio entre infraestructura y sustentabilidad mediante un esquema alternativo de gobernación, el cual sugiere acordar la creación de un área esencial para la conservación.This article studies the sociopolitical and environmental problems associated with the likely construction of a port at Punta Colonet in Baja California State. Announced as the federal government's main infrastructure project, it overlooks earlier commitments to conserving local resources and interests. The confrontation that has emerged between "developmentalists" and "conservationists" glosses over a major concern: institutional strength. As a result, the analysis is mainly based on regulations, government action and social participation. Moreover, a balance is proposed between infrastructure and sustainability through an alternative governance framework, whereby an area would be created especially for conservation.

  20. Numerical Simulation of Fault Interaction in a Trans-Tensional Setting, the La Paz Los Cabos Region, Baja California, Mexico.

    Science.gov (United States)

    Zielke, O.; Arrowsmith, R. J.

    2006-12-01

    A number of medium to large normal faulting earthquakes occurred in the La Paz-Los Cabos region, at the tip of Baja California, within the last four decades. They (along with the tectonic geomorphology of the fault zones on the Peninsula) demonstrate that the existing structures in the area are active and capable of hazardous earthquakes. The goal of this study is to understand how the individual active faults in this region affect the behavior of the fault system as a whole. What role does fault interaction (i.e., stress transfer) and earthquake triggering play in the La Paz-Los Cabos region? Do we know all the significant, active and therefore hazardous structures that are part of the fault system? Are these structures capable of releasing the tectonically accumulated strain? What role does that fault system play in the regional, trans-tensional setting? To approach these questions we utilize a numerical model, based on derivations by Okada (1992), with which we compute the strain distribution and Coulomb failure stress for a given (frictionless) displacement along a rectangular fault patch and its interactions with other faults of the fault array. Beginning with simple geometric models of the fault system in the La Paz-Los Cabos region, we investigate under what conditions individual earthquakes may have triggered subsequent events. We focused on the M =5.6 event on April 4th 1969 that may have had an effect on the timing of the M=6.2 event on June 30th 1995. The proximity of these two earthquakes (epicenters only 60km apart) supports the idea that stress transfer caused by the 1969 event may have altered the seismic cycle of the fault activated in 1995. Because fault geometry and slip distribution during these two events are not well known, we explore the parameter space to learn under what conditions the 1969 event may have triggered the 1995 event. We apply the empirical relations among magnitude, fault geometry, and displacement, derived by Wells

  1. Isotopic-chemical study of fluid of producing wells and natural springs from Las Tres Virgenes, Baja California Sur systems, Mexico. Estudio quimico-isotopico de fluidos de pozos productores y manantiales del sistema Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Portugal Marin, Enrique; Barragan, Rosa Maria; Arellano Gomez, Victor Manuel (Instituto de Investigaciones Electricas, Cuernavaca (Mexico)); Tello H, Enrique (Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)); Garcia, Consuelo (Residencia del Campo Geotermico Las Tres Virgenes, Baja California Sur (Mexico))

    1998-09-15

    Results of the chemical and isotopic studies from springs, domestic and geothermal wells in Las Tres Virgenes, Baja California Sur, Mexico are presented. Three water types were found to be in the study zone. Sulphate-type water at the North, bicarbonate-type waters at the South and sodium chloride type at the West. The last group includes the reservoir water. The estimated geothermometric temperature for the LV-1 well was 259 degrees Celsius with CCG geothermometer, while the estimated temperature for the springs were low, due to high dilution of the deep fluid with groundwater. The isotopic data (d[sup 18]O and dD) were used to define the local meteoric line, the isotopic composition of the reservoir recharge and the possible elevation where the reservoir recharge is likely to occur. Finally a discussion about the possible origin of the geothermal water based on the isotopic data is presented.

  2. Biomonitoring with Micronuclei Test in Buccal Cells of Female Farmers and Children Exposed to Pesticides of Maneadero Agricultural Valley, Baja California, Mexico

    Science.gov (United States)

    Castañeda-Yslas, Idalia Jazmin; Arellano-García, María Evarista; García-Zarate, Marco Antonio; Ruíz-Ruíz, Balam; Zavala-Cerna, María Guadalupe; Torres-Bugarín, Olivia

    2016-01-01

    Feminization of the agricultural labor is common in Mexico; these women and their families are vulnerable to several health risks including genotoxicity. Previous papers have presented contradictory information with respect to indirect exposure to pesticides and DNA damage. We aimed to evaluate the genotoxic effect in buccal mucosa from female farmers and children, working in the agricultural valley of Maneadero, Baja California. Frequencies of micronucleated cells (MNc) and nuclear abnormalities (NA) in 2000 cells were obtained from the buccal mucosa of the study population (n = 144), divided in four groups: (1) farmers (n = 37), (2) unexposed (n = 35), (3) farmers' children (n = 34), and (4) unexposed children (n = 38). We compared frequencies of MNc and NA and fitted generalized linear models to investigate the interaction between these variables and exposition to pesticides. Differences were found between farmers and unexposed women in MNc (p < 0.0001), CC (p = 0.3376), and PN (p < 0.0001). With respect to exposed children, we found higher significant frequencies in MNc (p < 0.0001), LN (p < 0.0001), CC (p < 0.0001), and PN (p < 0.004) when compared to unexposed children. Therefore working as a farmer is a risk for genotoxic damage; more importantly indirectly exposed children were found to have genotoxic damage, which is of concern, since it could aid in future disturbances of their health. PMID:26981119

  3. Can the Adoption of Desalination Technology Lead to Aquifer Preservation? A Case Study of a Sociotechnical Water System in Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Jamie McEvoy

    2015-09-01

    Full Text Available There is growing concern about the sustainability of groundwater supplies worldwide. In many regions, desalination—the conversion of saline water to freshwater—is viewed as a way to increase water supplies and reduce pressure on overdrawn aquifers. Using data from reports, articles, interviews, a survey, and a focus group, this paper examines if, and how, the adoption of desalination technology can lead to aquifer preservation in Baja California Sur (BCS, Mexico. The paper outlines existing institutional arrangements (i.e., laws, rules, norms, or organizations surrounding desalination in BCS and concludes that there are currently no effective mechanisms to ensure aquifer preservation. Four mechanisms that could be implemented to improve groundwater management are identified, including: 1 integrated water-and land-use planning; 2 creation of an institute responsible for coordinated and consistent planning; 3 improved groundwater monitoring; and 4 implementation of water conservation measures prior to the adoption of desalination technology. This paper concludes that viewing water technologies, including desalination, as sociotechnical systems—i.e., a set of technological components that are embedded in complex social, political, and economic contexts—has the potential to create a more sustainable human–environment–technology relationship. By assessing desalination technology as a sociotechnical system, this study highlights the need to focus on institutional development and capacity building, especially within local water utilities and urban planning agencies.

  4. Spatio-temporal evolution of aseismic ground deformation in the Mexicali Valley (Baja California, Mexico) from 1993 to 2010, using differential SAR interferometry

    Science.gov (United States)

    Sarychikhina, O.; Glowacka, E.

    2015-11-01

    Ground deformation in Mexicali Valley, Baja California, Mexico, the southern part of the Mexicali-Imperial valley, is influenced by active tectonics and human activity, mainly that of geothermal fluid extraction in the Cerro Prieto Geothermal Field. Significant ground deformation, mainly subsidence (~ 18 cm yr-1), and related ground fissures cause severe damage to local infrastructure. The technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) has been demonstrated to be a very effective remote sensing tool for accurately measuring the spatial and temporal evolution of ground displacements over broad areas. In present study ERS-1/2 SAR and ENVISAT ASAR images acquired between 1993 and 2010 were used to perform a historical analysis of aseismic ground deformation in Mexicali Valley, in an attempt to evaluate its spatio-temporal evolution and improve the understanding of its dynamic. For this purpose, the conventional 2-pass DInSAR was used to generate interferograms which were used in stacking procedure to produce maps of annual aseismic ground deformation rates for different periods. Differential interferograms that included strong co-seismic deformation signals were not included in the stacking and analysis. The changes in the ground deformation pattern and rate were identified. The main changes occur between 2000 and 2005 and include increasing deformation rate in the recharge zone and decreasing deformation rate in the western part of the CPGF production zone. We suggested that these changes are mainly caused by production development in the Cerro Prieto Geothermal Field.

  5. Lack of knowledge about mother-to-child HIV transmission prevention in pregnant women at Tijuana General Hospital, Baja California, Mexico.

    Science.gov (United States)

    Becka, Chandra M; Chacón-Cruz, Enrique; Araneta, Maria Rosario; Viani, Rolando M

    2015-01-01

    The objective of this study was to identify determinants of human immunodeficiency virus (HIV) knowledge regarding mother-to-child transmission (MTCT) among pregnant women at Tijuana General Hospital, Baja California, Mexico. Between March and November 2003, patients from the prenatal care (n = 1294) and labor and delivery (L&D) units (n = 495) participated in a cross-sectional study to measure HIV knowledge. Less than one-third (30%) knew that HIV could be transmitted to a child during delivery, and 36% knew that HIV could be transmitted by breast-feeding. Only 27% knew that an MTCT could be prevented. Prenatal patients were more likely to know that MTCT was preventable (prenatal: 31% versus L&D 25%; P = .02). Logistic regression indicated that prenatal patients (odds ratio = 1.49, confidence interval 1.07-2.07) were more likely to know that HIV could be transmitted through breast-feeding. Overall, both groups had poor knowledge regarding MTCT of HIV.

  6. New and noteworthy waterfowl records at artificial wetlands from Baja California Sur, Mexico Registros nuevos y sobresalientes de anátidos en humedales artificiales de Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Roberto Carmona

    2011-06-01

    Full Text Available We present 9 recent records of rare waterfowls in Baja California Sur, all of them in artificial wetlands: 3 freshwater sites and 1 concentration area for a saltworks. We present the first records of the Ross's Goose in the state. The remaining 8 species are: Black-bellied Whistling-Duck (breeding, Fulvous Whistling-Duck, Greater White-fronted Goose, Snow Goose, Cackling Goose, Tundra Swan, Mallard and Hooded Merganser. To this list we added an historical compilation of the records of these species in artificial sites of the state. The artificial wetlands are no replacement for their natural counterparts, they are nevertheless an important part of the region's landscape mosaic. As the records of the present work exemplify, this man-made habitat increases the regional species richness, and should be considered as important areas that need to be protected.Presentamos registros recientes de 9 especies de anátidos raros en Baja California Sur, todos ellos realizados en humedales creados por el hombre: 3 sitios dulceacuícolas y 1 área de concentración para la producción de sal. Se incluyen los primeros registros del ganso de Ross (Chen rossii para el estado. Las 8 especies restantes son: Dendrocygna autumnalis (anidación, D. bicolor, Anser albifrons, Chen caerulesens, Branta hutchinsii, Cygnus columbianus, Anas platyrhynchos y Lophodytes cucullatus. A la lista, agregamos una recopilación histórica de los registros de estas especies en humedales artificiales del estado. Aunque estos sitios no deben sustituir a sus contrapartes naturales, actualmente forman parte del mosaico paisajístico que ofrece la región; adicionalmente, incrementan la riqueza de especies de la región, por lo que es necesario brindarles protección.

  7. Tectonic and magmatic controls on the location of post-subduction monogenetic volcanoes in Baja California, Mexico, revealed through spatial analysis of eruptive vents

    Science.gov (United States)

    Germa, Aurélie; Connor, Laura J.; Cañon-Tapia, Edgardo; Le Corvec, Nicolas

    2013-12-01

    Post-subduction (12.5 Ma to less than 1 Ma) monogenetic volcanism on the Baja California peninsula, Mexico, formed one of the densest intra-continental areas of eruptive vents on Earth. It includes about 900 vents within an area ˜700 km long (N-S) and 70 to 150 km wide (W-E). This study shows that post-subduction volcanic activity was distributed along this arc and that modes exist in the volcano distribution, indicating that productivity of the magma source region was not uniform along the length of the arc. Vent clustering, vent alignments, and cone elongations were measured within eight monogenetic volcanic fields located along the peninsula. Results indicate that on a regional scale, vent clustering varies from north to south with denser spatial clustering in the north on the order of 1.9 × 10-1 vents/km2 to less dense clustering in the south on the order of 7.8 × 10-2 vents/km2. San Quintin, San Carlos, Jaraguay, and Santa Clara are spatially distinct volcanic fields with higher eruptive vent densities suggesting the existence of individual melt columns that may have persisted over time. In contrast, the San Borja, Vizcaino, San Ignacio, and La Purisima vent fields show lower degrees of vent clustering and no obvious spatial gaps between fields, thus indicating an area of more distributed volcanism. Insight into the lithospheric stress field can be gained from vent alignments and vent elongation measurements. Within the fields located along the extinct, subduction-related volcanic arc, elongation patterns of cinder cones and fissure-fed spatter cones, vent clusters, and vent alignments trend NW-SE and N-S. Within the Santa Clara field, located more to the west within the forearc, elongation patterns of the same volcanic features trend NE-SW. These patterns suggest that magmatism was more focused in the forearc and in the northern part of Baja California than in its southern region. Within the extinct arc, magma ascent created volcano alignments and elongate

  8. The role of tropical cyclones on landscape dynamics in southern Baja California, Mexico based on Late Pleistocene-Holocene alluvial stratigraphy

    Science.gov (United States)

    McDonald, Eric; Antinao, Jose Luis; Rhodes, Edward J.; Brown, Nathan; Gosse, John

    2015-04-01

    Region-wide alluvial records provide evidence that time-transgressive changes in climate can be a major driver of landscape evolution. Historically, landfall of eastern Pacific tropical cyclones in southwestern North America during the late summer and early fall provide the strongest storms that have demonstrated geomorphic impact on the landscape. The alluvial fan record of the southern portion of Baja California (Mexico) was investigated to determine if linkages exist between region-wide fluvial deposits and tropical cyclones. The regional distribution and Pleistocene to Holocene morphostratigraphy of alluvial fans has been established for the southern portion of Baja California with primary focus on the La Paz and San José del Cabo basins. Six discrete morphopedosedimentary alluvial units (Qt1 through Qt6) were differentiated across the region using a combination of geomorphologic mapping, sedimentological analysis, and soil development further reinforced with geochronology using radiocarbon, optically stimulated luminescence and cosmogenic depth-profiles. A first phase of regional aggradation began before ~ 100 ka (Qt1) and culminated ~10 ka (Qt4). After deposition of Qt4, increasing regional incision of older units and the progressive development of a channelized alluvial landscape coincide with deposition of Qt5 and Qt6 units in a second, incisional phase. All units are conformed of multiple 1-3 m thick alluvial packages deposited in upper-flow regime and representing individual storms. Aggradational units (Qt1-Qt4) covered broad (>2 km) channels in the form of sheetflood deposition while incisional stage deposits are mostly confined to channels of ~0.5-2 km width. Continuous deposition of the thicker sequences is demonstrated by closely spaced luminescence dates in vertical profiles. In a few places disconformities between major units are evident and indicated by partly eroded buried soils. Analysis of historical terraces as part of the younger units

  9. Numerical simulation of groundwater artificial recharge in a semiarid-climate basin of northwest Mexico, case study the Guadalupe Valley Aquifer, Baja California

    Science.gov (United States)

    Campos-Gaytan, J. R.; Herrera-Oliva, C. S.

    2013-05-01

    In this study was analyzed through a regional groundwater flow model the effects on groundwater levels caused by the application of different future groundwater management scenarios (2007-2025) at the Guadalupe Valley, in Baja California, Mexico. Among these studied alternatives are those scenarios designed in order to evaluate the possible effects generated for the groundwater artificial recharge in order to satisfy a future water demand with an extraction volume considered as sustainable. The State of Baja California has been subject to an increment of the agricultural, urban and industrials activities, implicating a growing water-demand. However, the State is characterized by its semiarid-climate with low surface water availability; therefore, has resulted in an extensive use of groundwater in local aquifer. Water level measurements indicate there has been a decline in water levels in the Guadalupe Valley for the past 30 years. The Guadalupe Valley aquifer represents one the major sources of water supply in Ensenada region. It supplies about 25% of the water distributed by the public water supplier at the city of Ensenada and in addition constitutes the main water resource for the local wine industries. Artificially recharging the groundwater system is one water resource option available to the study zone, in response to increasing water demand. The existing water supply system for the Guadalupe Valley and the city of Ensenada is limited since water use demand periods in 5 to 10 years or less will require the construction of additional facilities. To prepare for this short-term demand, one option available to water managers is to bring up to approximately 3.0 Mm3/year of treated water of the city of Ensenada into the valley during the low-demand winter months, artificially recharge the groundwater system, and withdraw the water to meet the summer demands. A 2- Dimensional groundwater flow was used to evaluate the effects of the groundwater artificial recharge

  10. A Study on the Attitudes and Opinions of Engineering Students from the University of Baja California, Mexico, on Science, Technology, and Society

    Science.gov (United States)

    Oliveros Ruiz, Maria Amparo; Sevilla Garcia, Juan Jose; Schorr, Michael

    2010-01-01

    A proposal is presented for the incorporation of the concepts of STS into the teaching of science and technology at the Faculty of Engineering, Mexicali Campus, of the University of Baja California. The method outlined for the development of research and the application of the "Opinions Questionnaire on Science, Technology and Society"…

  11. A Study on the Attitudes and Opinions of Engineering Students from the University of Baja California, Mexico, on Science, Technology, and Society

    Science.gov (United States)

    Oliveros Ruiz, Maria Amparo; Sevilla Garcia, Juan Jose; Schorr, Michael

    2010-01-01

    A proposal is presented for the incorporation of the concepts of STS into the teaching of science and technology at the Faculty of Engineering, Mexicali Campus, of the University of Baja California. The method outlined for the development of research and the application of the "Opinions Questionnaire on Science, Technology and Society" is…

  12. Interaction of Extreme Halophilic Archaea With the Evaporites of the Solar Salterns Guerrero Negro Baja California, Mexico

    Science.gov (United States)

    Tamez, P.; Lopez-Cortés, A.

    2008-12-01

    Hypersaline environments have been significant reservoirs for the long-term evolution of specifically adapted microorganisms. Characterized to have higher salt concentrations (up to 35 g/L), they are worldwide distributed and have a commercial significance. Exportadora de Sal, Guerrero Negro, Mexico has a multipond salterns system designed to harvest common salt (NaCl) from sea water. To achieve this purpose, sea water is pumped through a set of shallow ponds where water evaporates and salts concentrate. Sequential precipitation of CaCO3, CaSO4 2H2O and NaCl occurs in a mineral formations call it evaporites. In the interior of those gypsum-encrusted and halite-encrusted minerals, communities of extremely salt-loving archaea prosper. Previous studies have showed the influence of Haloarchaeal cells in the formation of larger fluid inclusions than crystals formed in sterile salt solutions. S-layer envelopes and cells of Haloarcula strain SP8807 contributed to the nucleation of new crystals of NaCl. Given the significance of the scope in phylogenetic archaeal diversity research, this study had a polyphasic approach. SEM micrographs from a 21- 31% (w/v) gradient salt multipond system evaporites, gave an insight profile of the extreme halophilic archaeal communities thriving in the surface of the gypsum and halite evaporites. Halite crystals were form after 21 days of incubation in solid medium with archaeal cells. Both culture and non-culture dependent methods, Nested-PCR-DGGE analysis and sequencing of 16S rDNA amplified fragment genes from environmental samples and isolated strains were used for this purpose. We isolate three strains from Pond 9 (21.07% total salt concentration) and one strain from Cristallizer 20 (25.15% total salt concentration). 16S rDNA signaling gave 99% of similarity with Halogeometricum borinquense, sequence AF002984, two other strains were 99% of similarity with Halobacterium salinarum, sequence AJ496185 these strains shown different colony

  13. Present-day loading rate of faults in southern California and northern Baja California, Mexico, and post-seismic deformation following the M7.2 April 4, 2010, El Mayor-Cucapah earthquake from GPS Geodesy

    Science.gov (United States)

    Spinler, J. C.; Bennett, R. A.

    2012-12-01

    We use 142 GPS velocity estimates from the SCEC Crustal Motion Map 4 and 59 GPS velocity estimates from additional sites to model the crustal velocity field of southern California, USA, and northern Baja California, Mexico, prior to the 2010 April 4 Mw 7.2 El Mayor-Cucapah (EMC) earthquake. The EMC earthquake is the largest event to occur along the southern San Andreas fault system in nearly two decades. In the year following the EMC earthquake, the EarthScope Plate Boundary Observatory (PBO) constructed eight new continuous GPS sites in northern Baja California, Mexico. We used our velocity model, which represents the period before the EMC earthquake, to assess postseismic velocity changes at the new PBO sites. Time series from the new PBO sites, which were constructed 4-18 months following the earthquake do not exhibit obvious exponential or logarithmic decay, showing instead fairly secular trends through the period of our analysis (2010.8-2012.5). The weighted RMS misfit to secular rates, accounting for periodic site motions is typically around 1.7 mm/yr, indicating high positioning precision and fairly linear site motion. Results of our research include new fault slip rate estimates for the greater San Andreas fault system, including model faults representing the Cerro Prieto (39.0±0.1 mm/yr), Imperial (35.7±0.1 mm/yr), and southernmost San Andreas (24.7±0.1 mm/yr), generally consistent with previous geodetic studies within the region. Velocity changes at the new PBO sites associated with the EMC earthquake are in the range 1.7±0.3 to 9.2±2.6 mm/yr. The maximum rate difference is found in Mexicali Valley, close to the rupture. Rate changes decay systematically with distance from the EMC epicenter and velocity orientations exhibit a butterfly pattern as expected from a strike slip earthquake. Sites to the south and southwest of the Baja California shear zone are moving more rapidly to the northwest relative to their motions prior to the earthquake. Sites to

  14. Media and nationalism in Baja California during World War II

    Directory of Open Access Journals (Sweden)

    Víctor M. Gruel Sández

    2013-01-01

    Full Text Available The purpose of this work is to explain some journalistic representations of the Northern Territory of Baja California. The body of documents that pertain this article, will document different versions of the past of the peninsula, from the nature of political discourse. Bajacalifornians will appear represented by journalists, struggling to eliminate an image of an isolated, uninhabited place filled with U.S. citizens. The editorial portrayal of the Tijuana, Mexicali and Mexico City press will be analyzed in context with the regional, national and international conflicts. Public opinion was a ground where the people of Baja California negotiated the nationalism, as the rest of the world collapsed with World War ii.

  15. Economic restructuring plan and emergent regions: Baja California, 1980-1995

    Directory of Open Access Journals (Sweden)

    Arturo Ranfla González

    2000-07-01

    Full Text Available The aim of this essay is to foster a discussion on the political and territorial levels that are involved in the process of economic globalization of the Northern border region of Mexico, and particularly the state of Baja California. For such purpose, an approach is taken on the economic and sectorial conditions of the Baja California economy during the 1981-1994 period. Also, a detailed analysis of the sectorial structure and dynamics of production —during that same period— of the main municipalities is Baja California in order to identify the profiles and hierarchy of each of them is carried out.

  16. El cardón Pachycereus pringlei, nuevo hospedero para Scyphophorus acupunctatus (Coleoptera: Curculionidae en Baja California Sur, México The giant cardon cactus Pachycereus pringlei, a new host for Scyphophorus acupunctatus (Coleoptera: Curculionidae in Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Yolanda Maya

    2011-09-01

    Full Text Available Se presenta el primer registro de una cactácea, Pachycereus pringlei (cardón, especie dominante del matorral xerófilo de la península de Baja California, como hospedero de Scyphophorus acupunctatus (picudo del agave. A partir de observaciones y la recolección de individuos adultos y larvas, se pudo establecer que el picudo del agave causa al menos 3 tipos de daño al cardón: 1, barrenado en la región apical de los brazos por los adultos; 2, consumo de la médula de los brazos por las larvas, que puede ser tan extenso que ocasiona la muerte del cardón y 3, perforaciones en diversos sitios de los brazos, por donde las larvas eliminan los desechos, que pueden ser entrada de otros parásitos o que por lo menos dejan cicatrices en forma de tumor. El éxito de este insecto en el cardón podría representar una amenaza para las poblaciones naturales de esta cactácea e incluso para los servicios ambientales de los matorrales xerófilos.This is the first record of a cactus, Pachycereus pringlei (giant cardon, which is a dominant species of the xerophyllous scrub in the Baja California peninsula, as a host of Scyphophorus acupunctatus (agave weevil. Based on observations and the sampling of adults and larvae, it was possible to establish that this weevil causes at least 3 types of damage to the cardon: 1, drilling of the tip of the branches by adults; 2, consumption of the branch medulla by larvae, which can be so extended that could cause the cardon’s death, and 3, perforations in the branches, used by larvae to eliminate wastes, that could serve as entrance to other pests and remain as tumor-like scars. The success that this insect seems to have by using the giant cardon cactus as host represents a threat to its natural populations and even to the xerophillous scrub environmental services.

  17. General characteristics of the diet of Trachinotus paitensis (Teleostei: Carangidae) from San Ignacio Lagoon, Baja California Sur, Mexico.

    Science.gov (United States)

    Cruz Escalona, V H; Abitia Cárdenas, L A

    2004-03-01

    The food habits of Trachinotus paitensis, in San Ignacio Lagoon B.C.S., Mexico, were investigated. We observed that T. paitensis is carnivorous, feeding mainly on benthic invertebrates (the gastropods Anachis spp., Bittium spp., and the crustacean larvae). We concluded that T. paitensis is an opportunist predator that impacts mainly on epibenthic invertebrates.

  18. Seismicity, focal mechanisms, and stress distribution in the Tres Virgenes volcanic and geothermal region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Victor; Munguia, Luis [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico)

    2006-01-15

    In October 1993 we carried out a seismic monitoring in the Tres Virgenes volcanic region in order to record the background seismicity associated with the volcanic structures, the geothermal field and the tectonic features of the area. Hypocenters for 257 microearthquakes were located in the volcanic edifices and along the northwest right-lateral, strike-slip La Virgen fault. Focal depths range from close to the Earth surface to about 8 km. Shallow depths occur mainly in the volcanic edifices. Deeper seismic events occurred outside the volcanic area. The duration magnitudes of the located microearthquakes range between 1 and 3. The Vp/Vs ratio and the low-Q values estimated suggest heterogeneous material properties in the volcanic structures mainly toward the El Azufre fault and the El Aguajito Caldera, where hydrothermal activity has been reported. The P- and T-axes of focal mechanisms for 90 microearthquakes suggest that the region is under N-S compression and E-W extension, in agreement with the regional tectonic stress field of the NW-SE right-lateral strike-slip transform fault system of the Gulf of California. [Spanish] En octubre de 1993 se llevo a cabo un monitoreo sismico en la region volcanica Las Tres Virgenes con el proposito de registrar la actividad sismica asociada a las estructuras volcanicas, al campo geotermico y a la tectonica local. Se localizaron 257 microsismos con hipocentros en los edificios volcanicos y a lo largo de la falla de rumbo, lateral derecha conocida como falla La Virgen. La profundidad focal de los sismos varia desde los muy cercanos a la superficie de la Tierra hasta los 8 km. Las profundidades someras ocurren principalmente en los edificios volcanicos. Los sismos mas profundos ocurren fuera del area volcanica. La magnitud de duracion de los microsismos localizados varia entre 1 y 3. La razon Vp/Vs y los valores bajos de Q que se estimaron en la zona sugieren un material con propiedades heterogeneas bajo las estructuras

  19. [Trophic ecology of the fish Arothron meleagris (Tetraodontiformes: Tetraodontidae) from Los Frailes reef, southern Baja California, Mexico].

    Science.gov (United States)

    Moreno, Xchel G; Abitia, L Andrés; Favila, Araceli; Gutiérrez, Francisco J; Palacios, Devis S

    2009-01-01

    Monthly samples were taken from November 2004 to October 2005 in the Los Frailes reef, BCS, Mexico. The objective was to determine the feeding habits of the pufferfish, Arothron meleagris, as well as possible variations in feeding patterns due to size and/or sex. We captured 101 specimens, with all stomachs contained food. The index of relative importance (IRI) was used to determine the main items; which were non-identified organic matter (NIOM) (30.44%), Echinometra vanbrunti (26.25 %), Porifera (12.63 %), Pocillopora spp. (11.84%), Bryozoa (5.37 %) and Porites spp. (4.83 %). Levin's index indicated a low trophic niche breadth (Bi=0.12) and allowed us to determine that A. meleagris is a specialist predator with strong preferences towards certain food types. The Morisita-Horn index showed a high trophic overlap between sexes (Clambda=0.78), seasons (hot and cold Clambda=0.95) and among sizes (small and medium Clambda=0.94; small and large Clambda=0.74; medium and large Clambda=0.83).

  20. [Length, body weight and sex of the golden Coryphaena hippurus (Perciformes: Coryphaenidae), of the littoral of Sinaloa, Nayarit and Baja California Sur, Mexico].

    Science.gov (United States)

    Madrid, J V; Beltrán-Pimienta, R

    2001-01-01

    Dolphin fish population data were recorded from landings in Sinaloa, Nayarit and Baja Califonia Sur, Mexico, in 1997. Of 3,211 organisms, only 2,812 produced complete biometric data. The maximal length and weight were 192 cm and 30 kg. The three sampling sites and the climatic periods also were associated with different size (P < 0.05). The covariate analysis of weight and length relationships indicated significative differences (P < 0.05) for total data and by sex. Condition factor was higher throughout the study period in Mazatlán, and the variation was higher, in the spring. The sexual ratio was in Mazatlán constant, while there were more males in Nayarit in the fall and the spring and in Los Cabos in the spring. There may be population differences, between the central mexican Pacific Coast and the Peninsula of Baja data.

  1. Microfaunal evidence of age and depositional environments of the Cerro Prieto section (Plio-Pleistocene), Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ingle, J.C. Jr.

    1982-01-01

    Microfossils including benthic and planktic foraminifera, ostracodes, calcareous algae, fish skeletal material, and fragments of pelecypods were found in 14 core samples from depths of 185 to 1952 m in the Cerro Prieto geothermal field, providing evidence of both the age and depositional history of sediments comprising the 3000-m-thick Pliocene and Pleistocene section in this area. Ostracodes of brackish water and marine origin constitute the most common microfossils present in this sequence occurring in 8 samples; in situ littoral and neritic species of benthic foraminifera occur in 5 samples with planktic species present in 2 samples. Distributional patterns of ostracodes and foraminifera together with previously analyzed lithofacies (Lyons and van de Kamp, 1980) indicate that the Cerro Prieto section represents an intertonguing complex of alluvial, deltaic, estuarine, and shallow marine environments deposited along the front of the Colorado River delta as it prograded across the Salton Trough during Pliocene and Pleistocene time. Foraminiferal evidence indicates that a sand and shale unit commonly present at depths between 700 and 1100 m represents a significant mid-Pleistocene marine incursion in the Cerro Prieto area. Tentative correlation of the Cerro Prieto section with the well dated Palm Springs Formation of the Imperial Valley, California area suggests that the Pliocene/Pleistocene boundary occurs at a depth of approximately 2000 m in the area of well M-93. Reworked specimens of Cretaceous foraminifera and fragments of the Cretaceous pelecypod Inoceramus were found in five samples further substantiating the Colorado Plateau provenance of a significant portion of the Colorado River deltaic sediments in the Cerro Prieto area.

  2. Structural Geometry of a Sector of the Colorado River Delta, Baja California, Mexico, Based on Seismic Reflections

    Science.gov (United States)

    Chanes-Martínez, J. Juan; González-Escobar, Mario; Suárez-Vidal, Francisco; Gallardo-Mata, Clemente G.

    2014-07-01

    A structural study in the SW section of the Colorado River delta using seismic reflection data is presented. The study area is located along the Cerro Prieto transform fault, which extends from the northern Gulf of California through the Mexicali Valley and is an active fault within the Pacific-North American plate boundary zone. The research was supported by a database of five seismic profiles with a total length of 215 km, collected in the early 80's by Petróleos Mexicanos. The results show a high density of faults, most of which are buried by sediments. Within the Cerro Prieto fault zone, several faults were identified, such as: Palmas, Mesa, and Pangas Viejas, until now unknown. In addition, even though the Indiviso fault was investigated and superficially identify prior to this work, herein mapped at depth. West of the Cerro Prieto fault zone lies the Las Tinajas basin, bound by the Dunas and Saldaña faults and by the Montague basin to the southeast. The deformation zone along the plate boundary is 18-km-wide, stretching from the Cerro Prieto fault in the east to the Pangas Viejas fault in the west. The orientations of the faults are NW-SE, and if projected from the southern side of the Sierra Cucapah southward, the faults tend to join the Cerro Prieto fault. In the Las Tinajas basin, the acoustic basement is deeper than 5,000 m. Some of the largest vertical displacements generated by the 2010 7.2-Mw El Mayor-Cucapah earthquake occurred southeast of the epicenter and coincided with the location of the Pangas Viejas Fault, which is buried by sediments. Before this event, seismic activity was very low, and no structures were known in the area. In this paper, we demonstrate that there are at least seven major faults that may now pose a high seismic hazard.

  3. Silica-carbonate stromatolites related to coastal hydrothermal venting in Bahía Concepción, Baja California Sur, Mexico

    Science.gov (United States)

    Canet, Carles; Prol-Ledesma, Rosa María; Torres-Alvarado, Ignacio; Gilg, H. Albert; Villanueva, Ruth Esther; Cruz, Rufino Lozano-Santa

    2005-01-01

    Submarine diffused seepage (from 5 to 15 m depth) and intertidal focused gasohydrothermal venting take place on the West shore of the Bahía Concepción Bay, on Baja California, Mexico. The intertidal venting consists of a cluster of hot springs that occur a few meters offshore, with vent temperatures up to 62 °C and a pH of 6.68. Two irregularly shaped patches of silica-carbonate hot spring deposits occur around the main intertidal vent areas. In addition, a fossil bed of silica-carbonate hot spring deposits of about 75 m long crops out along a cliff next to the active vent area. Both fossil and modern silica-carbonate deposits are finely laminated, and form columnar, bulbous and smooth undulating microstromatolites up to 10 cm thick. Noncrystalline opal-A is the only silica phase present in the modern and fossil hot spring deposits and occurs as microspheres up to 300 nm in diameter forming porous aggregates and irregular clusters, chains and spongy filament networks. The silica supersaturation state of the thermal fluid necessary for opal precipitation is achieved by cooling when it reaches the surface. The presence of preserved microbial remains (diatoms and possibly filamentous microbes) in both modern and fossil deposits reflects the biological activity around the hot springs. The biological activity constrains the fabrics and the textures of the deposit, and could mediate silica deposition. Calcite is the most abundant crystalline phase in the hot spring deposits and forms discontinuous horizons of subhedral bladed crystals within the silica aggregates. Calcite crystals are unusually enriched in 13C, with δ13C V-PDB values between +3.0‰ and +9.3‰. The large 13C enrichment is attributable to a geothermal CO 2 degassing process, which yields calcite supersaturation. The δ18O V-PDB values in calcite, between -10.0‰ and -6.6‰, indicate precipitation from a hot spring fluid that is a mixture of seawater and meteorically derived water. With the methods

  4. Economic, environmental and social impacts of geothermal development, and energy savings and efficient use of power in Baja California, Mexico; Impactos economicos, ambientales y sociales del desarrollo geotermico y del ahorro y uso eficiente de la electricidad en Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Campbell R, Hector E.; Montero A, Gisela [Universidad Autonoma de Baja California, Instituto de Ingenieria, Mexicali, Baja California (Mexico)]. E-mail: hecr@iing.mxl.uabc.mx; Lambert A., Alejandro A. [Universidad Autonoma de Baja California, Facultad de Ingenieria, Mexicali, Baja California (Mexico)

    2011-01-15

    This essay of electrical planning for Baja California, Mexico, includes diagnosis of power production and consumption from 1994-2005, prospective to 2025 if historical trends are maintained, discussion of a systemic plan and its impact on the prospective through energy savings and energy efficient use, combined with an increase of the geothermal energy share. Diagnosis indicates that geothermal capacity in 1998 accounted for 57% of total electric capacity in Baja California, and by 2004 73% of this total electric capacity was based on natural gas, increasing energy dependence on fossil fuels. During this period, electric generation changed from a ratio of 2 to 1 (geothermal steam to fuel oil) to 1 to 1 (geothermal steam to natural gas). The unit cost of natural gas energy with an efficiency of 50% is 24 times the cost of the same unit of geothermal steam with 16% efficiency. Power generation, with fuel oil or simple cycle turbines firing natural gas, costs twice that of combined cycle turbines, while the costs are three times less with geothermal steam. In 2005, as a consequence of a minor contribution of geothermal energy to the power-generation total, production costs increased, reaching $122.80 USD/MWh. The replacement of fuel oil, as power fuel, decreased the SO{sub x} emissions from 4.16 kg/MWh to 0.19 kg/MWh. The combined-cycle fired by natural gas diminished the relative emissions of NO{sub x} and CO{sub 2} by 30%, but the 2.6 million tons of CO{sub x} given off each year did no vary significantly. Using geothermal energy avoids burning 20 million barrels of oil equivalent annually. The Prospective 2005-2025 indicates Baja California requires the installation of an additional 4500 MW to reach 7200 MW. The energy portfolio will become more dependent on natural gas increasing its share from 60% to 86%. Geothermal energy will decrease its share in installed capacity to 10%, eliminating the damping effect on the cost of production. SO{sub x} emissions will

  5. Horizontal movements, vertical-habitat utilization and diet of the jumbo squid ( Dosidicus gigas) in the Pacific Ocean off Baja California Sur, Mexico

    Science.gov (United States)

    Bazzino, Gastón; Gilly, William F.; Markaida, Unai; Salinas-Zavala, César A.; Ramos-Castillejos, Jorge

    2010-07-01

    We deployed four pop-up archival-transmitting (PAT) tags on jumbo squid ( Dosidicus gigas) collected in the Pacific Ocean off the main entrance to Magdalena Bay on the Baja California peninsula in June 2005. This is the first successful deployment of PAT tags on jumbo squid in an area outside the Gulf of California. Summary data were obtained through the ARGOS satellite system for three of the tags; the fourth tag was physically recovered. All of the tagged squid tended to remain on the shallow continental shelf for several days after tagging and then moved offshore into deeper water. Three of the four squid appeared to migrate in a general southerly direction while the fourth remained offshore of Magdalena Bay. All of the squid spent most daylight hours at depths that were associated with the hypoxic oxygen minimum layer, and at night they spent a majority of time in the upper 50 m of the water column. Stomach content analysis and tag temperature-depth data during the first days after tagging revealed that the squid were feeding on pelagic red crabs ( Pleuroncodes planipes) and several larger, neritic fishes over the continental shelf off Magdalena Bay during a seasonal nearshore upwelling. Comparison of our results with those previously collected in the Gulf of California reveal that Dosidicus gigas can vary its behavior and diet to suit local environmental conditions. This adaptability is likely to be an important factor in the ability of D. gigas to invade and colonize new areas.

  6. Learning in Baja California micro-enterprises

    Directory of Open Access Journals (Sweden)

    Michelle Texis Flores

    2011-01-01

    Full Text Available 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.

  7. Los molokanos rusos de Baja California

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    Therese Adams Muranaka

    1987-09-01

    Full Text Available La finalidad de esta investigación es aproximarse un poco más y averiguar quiénes son los molokanos y por qué huyeron de la Rusia imperial. Con este fin es necesario buscar las fuentes de la cristiandad ortodoxa. La separación de la iglesia católica y el catolicismo griego se dio en 1054, y seiscientos años después en 1654, sobreviene otra separación entre los ortodoxos rusos, de allí surgen los "creyentes a la antigua". En 1905, una colonia de agricultores rusos se estableció en el norte de Baja California, en el valle de Guadalupe, la cual ahora es conocida como Francisco Zarco o "colonia rusa". Aunque este artículo no llega a una conclusión para clasificar a este grupo, se espera que este estudio ilustre el parentesco étnico entre todos los colonos del valle. Se pueden diseñar algunas líneas susceptibles para su uso posterior en las que los lugares arqueológicos sugieren la etnicidad; aunque sin contar con la información histórica.

  8. Anisotropy of Magnetic Susceptibility (AMS) of the Neogene Volcanic Succession at the Sierra Juarez - Las PintasVolcanic Province, Northeastern Baja California, Mexico: Preliminary Results

    Science.gov (United States)

    Mendoza-Borunda, R.; Cañón-Tapia, E.; Suárez-Vidal, F.; Gradilla-Martínez, L.

    2010-12-01

    The Sierra Juarez-Las Pintas Volcanic Province is among the largest in northern Baja California. For this work, we focused on a bimodal volcanic succession of late Miocene age, composed of an extensive ignimbrite unit and few dispersed basaltic flows that crop out in central Sierra Juarez and northern Sierra Las Tinajas. The ignimbrite is zoned, composed by three distinctive members: a basal unwelded white tuff, a mid-section unwelded orange tuff, and an upper red welded tuff. The basaltic flows are olivine-rich. Samples were collected in five sites that define a NE-SW section across the Sierra Juarez Escarpment, in the western boundary of the so-called Gulf Extensional Province. In each of these sites a stratigraphic column composed of more than one geologic unit was sampled. The total number of analyzed cores is ca. 160. The preliminary results show vertical and lateral variations of the AMS of the ignimbrite that can be interpreted in terms of the local flow direction and processes of emplacement of these volcanic deposits. Such variations, in turn, are likely to reflect variations in the dynamics of the eruptive process that produced them. Although the AMS of all the rocks in this province display a complex set of orientations, in this work is shown that when examined in detail important clues concerning the geological evolution of the province can be obtained from these data.

  9. Biomagnification of mercury and its antagonistic interaction with selenium in yellowfin tuna Thunnus albacares in the trophic web of Baja California Sur, Mexico.

    Science.gov (United States)

    Ordiano-Flores, Alfredo; Rosíles-Martínez, Rene; Galván-Magaña, Felipe

    2012-12-01

    Mercury and selenium concentrations were determined in muscle of 37 yellowfin tuna (Thunnus albacares) captured aboard of Mexican purse-seiners boats off western coast of Baja California Sur, between Punta Eugenia and Cabo Falso, from October to December 2006. Also, its prey (mainly, jumbo squid Dosidicus gigas and pelagic red crab Pleuroncodes planipes) were analyzed from the stomach contents. All the mercury values obtained were lower that mercury content recommended by standard legal limits for seafood adopted by Mexican norms (typically 0.5-1.0μg g(-1)). Mercury concentrations vary between 0.06 and 0.51μg g(-1) in yellowfin tuna, and from 0.01 to 0.20μg g(-1) in its prey, suggesting that mercury can accumulate in prey tissues and that of their predator. Biomagnification factors (BMF) between predator-prey associations were calculated. The BMFs were >1, indicating that mercury biomagnifies along the food web of yellowfin tuna. In all species studied there was a molar excess of selenium over mercury. The rank order of mean selenium/mercury molar ratios was for pufferfish (42.62)> diamond squid (15.09)>yellowfin tuna (10.29)>pelagic red crab (10.05)>panama lightfish (9.54)> jumbo squid (8.91). The selenium health benefit value (Se-HBV) was calculated to have an improved understanding of the health benefits and risk of fish consumption.

  10. Estimación de Factores de Emisión de PM10 y PM2.5, en Vías Urbanas en Mexicali, Baja California, México Estimation of PM10 and PM2.5 Emission Factors, in City Roadways of Mexicali, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Lourdes M Meza

    2010-01-01

    Full Text Available El objetivo de esta investigación es estimar los factores de emisión (FE que permitan valorar la cantidad de material particulado de las vías pavimentadas y no pavimentadas de la ciudad de Mexicali, Baja California, México. Se empleó el modelo AP-42 de la US EPA, bajo un diseño estadístico al azar, correspondiente a 60 sitios de muestreo en un mapa georeferenciado con proyección UTM 11 Norte. Se obtuvieron los valores de carga y porcentaje de sedimento menor a 75 µm en laboratorio, velocidad y número de vehículos, en campo. La estimación de los FE corresponden a 0.92 Kg. PM10/VKT y 0.73 Kg. PM2.5 /VKT en vías pavimentadas y 2.33 Kg. PM10/VKT y 0.58 Kg. PM2.5 /VKT en vías no pavimentadas, respectivamente. El valor de FE propio determina la cantidad de material particulado a suspenderse y la relación de los factores de emisión (PM10 y PM2.5 en ambas vías indica que es necesario hacer mantenimiento y control de flujo de vehículos.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.

  11. Mapping variations in weight percent silica measured from multispectral thermal infrared imagery - Examples from the Hiller Mountains, Nevada, USA and Tres Virgenes-La Reforma, Baja California Sur, Mexico

    Science.gov (United States)

    Hook, S.J.; Dmochowski, J.E.; Howard, K.A.; Rowan, L.C.; Karlstrom, K.E.; Stock, J.M.

    2005-01-01

    Remotely sensed multispectral thermal infrared (8-13 ??m) images are increasingly being used to map variations in surface silicate mineralogy. These studies utilize the shift to longer wavelengths in the main spectral feature in minerals in this wavelength region (reststrahlen band) as the mineralogy changes from felsic to mafic. An approach is described for determining the amount of this shift and then using the shift with a reference curve, derived from laboratory data, to remotely determine the weight percent SiO2 of the surface. The approach has broad applicability to many study areas and can also be fine-tuned to give greater accuracy in a particular study area if field samples are available. The approach was assessed using airborne multispectral thermal infrared images from the Hiller Mountains, Nevada, USA and the Tres Virgenes-La Reforma, Baja California Sur, Mexico. Results indicate the general approach slightly overestimates the weight percent SiO2 of low silica rocks (e.g. basalt) and underestimates the weight percent SiO2 of high silica rocks (e.g. granite). Fine tuning the general approach with measurements from field samples provided good results for both areas with errors in the recovered weight percent SiO2 of a few percent. The map units identified by these techniques and traditional mapping at the Hiller Mountains demonstrate the continuity of the crystalline rocks from the Hiller Mountains southward to the White Hills supporting the idea that these ranges represent an essentially continuous footwall block below a regional detachment. Results from the Baja California data verify the most recent volcanism to be basaltic-andesite. ?? 2005 Elsevier Inc. All rights reserved.

  12. Diversidad filogenética de especies de Microcoleus de costras biológicas de suelo de la península de Baja California, México Phylogenetic diversity of Microcoleus species from biological desert crusts of the Baja California Peninsula, Mexico

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    Alejandro López-Cortés

    2010-04-01

    Full Text Available Microcoleus vaginatus fue proclamada como especie cosmopolita. Este supuesto no lo confirman los estudios morfológicos previos que se realizaron en poblaciones naturales de costras de suelo en una región con historia geológica particular, llamada sierra de la Laguna (SL, al sur de la península de Baja California (México. Por ello, en este estudio se comparó la estructura de comunidades de cianobacterias, con énfasis en el género Microcoleus, en costras biológicas de 10 localidades situadas a lo largo de la península. Se analizaron y cotejaron poblaciones naturales de cianobacterias con cepas tipo de colecciones públicas: Microcoleus sociatus (Sammlung von Algenkulturen Germany-SAG 26.92, M. paludosus (SAG 1445. 1a, M. vaginatus (Pasteur Culture Collection-PCC 9802 y M. chthonoplastes (PCC 7420. Se realizaron análisis microscópicos y de clusters de patrones de bandeado de secuencias del 16S rRNA, obtenidos por electroforesis de gel en gradiente desnaturalizante (DGGE. En los análisis microscópicos de muestras naturales no se detectaron morfotipos de M. vaginatus en 6 de las 10 localidades, 4 de ellas de la SL. La comparación de patrones de bandeado obtenidos por DGGE mostró diferencias significativas en la estructura de las comunidades de cianobacterias y ausencia de bandas equivalentes a M. vaginatus (PCC9802, en todas las localidades de la SL.Microcoleus vaginatus has been proclaimed to be a cosmopolitan species. However, morphological studies performed on natural populations of cyanobacterial crusts in a region with a particular geological history at the southern part of the Baja California Peninsula, Mexico, called Sierra de la Laguna (SL, do not support the last assertion. We compared the community structure of cyanobacteria, with emphasis in the genus Microcoleus, in biological desert crusts from 10 different localities along the Baja California Peninsula. We analyzed natural cyanobacterial populations and matched them with

  13. Arsenic content in groundwater from the southern part of the San Antonio-El Triunfo mining district, Baja California Sur, Mexico

    Science.gov (United States)

    Wurl, Jobst; Mendez-Rodriguez, Lía; Acosta-Vargas, Baudilio

    2014-10-01

    The San Antonio-El Triunfo mining district is located in a mountain region 60 km southeast of La Paz, the capital of the Mexican state of Baja California Sur. Mining activities, focused on gold and silver extraction, which began in the second half of the 18th century; the main activity took place between 1878 and 1911. The minerals were treated through the cyanide method, burned, and smelted. In effect between 800,000 and 1 million tons of mine waste materials were scattered in an area of approximately 350-400 km2. This area contains today several byproducts as a result from arsenopyrite oxidation, such as arsenolite (As2O3). The aim of this study was to analyze groundwater composition in order to define the actual concentrations of relevant parameters to detect ore mining contaminations, especially in respect to arsenic. In the autumn of 2010, 29 groundwater samples were obtained using flow-through bailer or down-hole pump methods, and a total of 37 variables were measured in each sample. Arsenic (dissolved) exceeded the values established by the World Health Organization (WHO, 2011) (0.01 mg/L) in 41% of the monitored sites. The maximum concentration of arsenic found in one observation well was 0.45 mg/L. Four water samples, which were characterized by elevated concentration of boron (max. conc. 9.5 mg/L), fluoride (max. conc. 3.25 mg/L) and alkaline pH values (>9), showed a composition typical for hydrothermal water. Because all four samples had arsenic concentration under 0.008 mg/L, we conclude that no significant impact of arsenic from hydrothermal fluids is found in the study area.

  14. [Spatial and biogeographic characterization of macroalgal assemblages from Bahía del Rincón, Baja California Sur, Mexico].

    Science.gov (United States)

    Riosmena-Rodríguez, R; Hinojosa-Arango, G; López-Vivas, J M; León-Cisneros, K; Holguin-Acosta, E

    2005-01-01

    Macroalgal studies in Baja California Sur have dealt mainly with occurrence and seasonality, but some areas are poorly known even for these basic data. Bahia del Rincón-La Rivera is an important high-productivity fisheries area where coastal infrastructure development is under way. A spatial characterization of the marine flora from Bahia del Rincón-La Rivera was done by intensive sampling at different depths and localities with skin and SCUBA diving. At least 500 m2 were surveyed in each site. Additionally. quantitative sampling was done in ten random 25 cm2 quadrates per site. In the intertidal section, density and cover estimates were used. We also investigated the historical records and geographical affinities. A total of 72 species were identified (most were red algae: 62%). We found no general trend in the biogeographical affinities, which varied with each taxonomic group. Most brown algae species were tropical-endemic; red algae temperate-cosmopolite and green algae tropical-cosmopolite. In the spatial assemblage structure we found a high similarity between the intertidal areas, but a low similarity in shallow or deeper areas (3-5 m). This pattern was the same when we compared the abundance of the main species. We suggest that there are significant spatial differences in recruitment and development of the assemblages in relation to vertical distribution (depth) and position along the shore. There is a clear-cut Gelidium-Jania belt in the intertidal zone and a Padina-Dictyota belt below the low tide. Sporadic and year-round species occur in the intertidal zone, annual and perennial species below the low tide line. Sites differ in recruitment and this affects the abundance of other species (such as coraline and Caulerpa species). Temperature and sedimentation affect seasonality, but community structure is relatively constant throughout the year.

  15. Adult Demography and Larval Processes in Coastal Benthic Populations: Intertidal Barnacles in Southern California and Baja California

    Science.gov (United States)

    2005-09-01

    WHOI Academic Programs Office, and through a Presidential Fellowship (Beca Presidente de la Reptiblica) from the Chilean Ministerio de Planificaci6n y...Planificaci6n y Cooperaci6n), which provided funds for the first three years of my doctoral studies through a Presidential Fellowship (Beca Presidente de la...Punta Baja (29°57.25’N, 115󈧴.64’W) in Baja California, Mexico (Fig. 4.1). Seven sites were visited approximately monthly over 16-month period (Table

  16. An annotated distributional checklist of exotic freshwater fishes from the Baja California Peninsula, Mexico Lista comentada sobre la distribución de peces dulceacuícolas exóticos de la península de Baja California, México

    Directory of Open Access Journals (Sweden)

    Gorgonio Ruiz-Campos

    2012-03-01

    Full Text Available We documented the distributional status of 27 exotic fish species in the inland waters of the Baja California Peninsula, Mexico, based on voucher specimens collected from 122 sites between 1977 and 2010, and on published records. The species reported here are representatives of genera from the Atlantic drainages of North America (Ictalurus, Ameiurus, Pylodictis, Morone, Lepomis, Pomoxis, Dorosoma, Cyprinella, and Micropterus, Middle America (Poecilia, Gambusia, and Xiphophorus, Eurasia (Cyprinus and Carassius, and Africa (Tilapia and Oreochromis. The family containing the highest number of species is Centrarchidae (7 species followed by Ictaluridae and Poeciliidae (6 species each. Four species were determined to be invasive due to their wide distribution and fast dispersal through the Peninsula (Gambusia affinis, Poecilia reticulata, Lepomis cyanellus, and Tilapia sp. cf. zillii. We analyze the impacts of exotic species on the native populations of 3 species with problems of conservation: Cyprinodon macularius (endangered, Fundulus lima (endangered, and Gasterosteus aculeatus (vulnerable. Alien fishes have been introduced for a variety of reasons in Mexico: ornament, sport, aquaculture, biological control, and by accident. In some cases fish introductions were carried out for more than one reason.El estatus de la distribución de peces exóticos es documentado para 27 especies en las aguas continentales de la península de Baja California, México, basado en registros de ejemplares recolectados en 122 localidades durante el período de 1977 a 2010, así como registros referidos en la literatura. Las especies aquí reportadas son representativas de géneros que proceden de la vertiente Atlántica de Norteamérica (Ictalurus, Ameiurus, Pylodictis, Morone, Lepomis, Pomoxis, Dorosoma, Cyprinella y Micropterus, Mesoamérica (Poecilia, Gambusia y Xiphophorus, Eurasia (Cyprinus y Carassius y África (Tilapia y Oreochromis. La familia con mayor n

  17. Distribution, genetic structure, and conservation status of the rare microendemic species, Guaiacum unijugum (Zygophyllaceae in the Cape Region of Baja California, Mexico Distribución, estructura genética y conservación de la especie microendémica Guaiacum unijugum (Zygophyllaceae en la región de los Cabos de Baja California, México

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    Ross A. McCauley

    2010-12-01

    Full Text Available Guaiacum unijugum is a rare shrub endemic to a 70 km stretch of coastline extending east from San José del Cabo in Baja California and is the least well-known of the 4 species of Guaiacum in Mexico. To increase our knowledge of this species and assess its conservation status we surveyed the extent of occurrence using both herbarium material and field work, assessed levels of genetic diversity, determined its phylogenetic relationships, and completed an evaluation of risk of extinction (MER. Herbarium material identified 5 known localities of occurrence with field work verifying the continued persistence of 4 of these with an additional site discovered. Genetic analysis across the small range using 17 microsatellite loci showed very low levels of genetic diversity with a mean expected heterozygosity (H E of 0.162 over all polymorphic loci. Most loci were found to be monomorphic and genetic divergence was small, maintained by the presence of rare private alleles in widely-separated populations. Phylogenetic analysis indicated a sister group relationship to G. coulteri along the Pacific coast suggesting vicariance for the origin and occurrence of G. unijugum. The unique evolutionary history coupled with current small population sizes warrants increased conservation via listing as a critically endangered species.Guaiacum unijugum es un arbusto endémico en un área de aproximadamente 70 km en la región de Los Cabos, Baja California Sur, siendo la menos estudiada de las 4 especies de Guaiacum en México. Para incrementar nuestro conocimiento sobre esta especie y determinar su estatus de conservación se realizó un censo de sus poblaciones determinándose su estructura genética, su relación filogenética con otros miembros del género y se calculó su riesgo de extinción (MER. La revisión de material de herbario, confirmó la presencia de 4 poblaciones a las que se sumó el hallazgo de 1 más. Mediante el uso de 17 loci de microsatélites se

  18. Interdisciplinary approach on evaluation and sustainable usage of the water resources in the semi-arid Northwest Mexico to counter the imbalance of water: Case study Valle de Guadalupe, Baja California

    Science.gov (United States)

    Kretzschmar, T.; Hernandez, R.; Valenzuela, C.; Cabello, A.

    2012-12-01

    In the Baja California peninsula are several watersheds present, of which the hydrogeological conditions are of great importance to communities in the area. The Valle de Guadalupe watershed, for instance has a wine industry of national importance. Irrigation of crops is carried out exclusively with water from the aquifer, which consists of Quaternary sediments filling this depression of Post-Miocene age. Apart from the use of the aquifer by the wine industry, the water utility of Ensenada operates 10 drinking water wells with a total capacity of 320 L/s or 42% of supply in the valley. In the arid northern Mexico mountain front recharge is an important recharge source to the aquifers. Other important recharge sources are related to direct infiltration of the precipitation, recharge from runoff into streams (mountain block recharge) and the provision by active faults. The knowledge of the aquifer is crucial to maintain sustainable management of water resources in the Valle de Guadalupe. This intense use of water resources is reflected in a degradation of the aquifer water quality and reduced water table. The integrated approach for a sustainable evaluation and usage of the aquifer includes besides the hydrogeological evaluation, the determination of the water stress on the vineyards as well as the usage of treated waste water as alternative resource as well the evaluation of the effects of climatic variations and measurement and modeling of the vegetation, the main interface between atmosphere and soil, affecting the hydrology in the process of interception, infiltration, runoff and evapotranspiration. With these detailed ongoing studies we expect to identify and counter imbalance of water in the study area. This requires 1) modeling and hydrogeological studies for the determination of the present and future imbalance 2) estimation of the impacts of industrial activities on water resources 3) characterization of alternative water sources, 4) optimization of the water

  19. Osprey distribution, abundance, and status in western North America: III. The Baja California and Gulf of California population

    Science.gov (United States)

    Henny, C.J.; Anderson, D.W.

    1979-01-01

    -An estimated 810 ? 55 pairs (minimum estimate) of ospreys (Pandion haliaetus) were nesting in the study area during our survey (24 March-l April 1977). Approximately 174 pairs nested along the Pacific side of Baja California, 255 pairs along the gulf side, 187 pairs on the Midriff Islands, and 194 pairs in coastal Sonora and Sinaloa. Most nested on cliffs adjacent to the sea (59%); some nested on cactus in flat terrain (26%). Seven per cent nested on the ground, three percent nested in mangroves and other trees in the southern portion of the study area,.and four percent nested on man-made structures. The extreme northwestern Baja California population that was extirpated early in this century has not recovered. However, several populations immediately to the south along the Pacific Coast now appear stationary. Pesticide residues in osprey eggs from Mexico were among the lowest reported for the species in North America.

  20. Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006-2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

    Science.gov (United States)

    Sarychikhina, Olga; Glowacka, Ewa; Robles, Braulio; Nava, F. Alejandro; Guzmán, Miguel

    2015-11-01

    Ground deformation and seismicity in Mexicali Valley, Baja California, Mexico, the southern part of the Mexicali-Imperial valley, are influenced by active tectonics and human activity. In this study, data from two successive leveling surveys in 2006 and 2009/2010 are used to estimate the total deformation occurred in Mexicali Valley during 2006-2009. The leveling data span more than 3.5 years and include deformation from several natural and anthropogenic sources that acted at different temporal and spatial scales during the analyzed period. Because of its large magnitude, the aseismic anthropogenic deformation caused by fluid extraction in the Cerro Prieto geothermal field obscures the deformation caused by other mechanisms and sources. The method of differential interferograms stacking was used to estimate the aseismic (interseismic tectonic and anthropogenic) components of the observed displacement, using SAR images, taken in 2007 during a period when no significant seismicity occurred in the study area. After removing the estimated aseismic signal from the leveling data, residual vertical displacement remained, and to identify possible sources and mechanisms of this displacement, a detailed analysis of records from tiltmeters and creepmeters was performed. The results of this analysis suggest that the residual displacement is mainly caused by moderate-sized seismicity in the area of study. Modeling of the vertical ground deformation caused by the coseismic slip on source fault (primary mechanism) of the two most important earthquakes, May 24, 2006 (Mw = 5.4) and December 30, 2009 (Mw = 5.8), was performed. The modeling results, together with the analysis of geotechnical instruments data, suggests that this moderate-sized seismicity influences the deformation in the study area by coseismic slip on the source fault, triggered slip on secondary faults, and soft sediments deformation.

  1. Comercio y crecimiento económico en Baja California

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    Juan Manuel Ocegueda Hernández

    2005-01-01

    Full Text Available En este trabajo se estima la tasa de crecimiento de equilibrio comercial de Baja California siguiendo el enfoque desarrollado por Kaldor (1970, Dixon y Thirlwall (1975 y Thirlwall y Dixon (1979, en el que se destaca la importancia de las exportaciones y de la especialización en actividades con altos multiplicadores dinámicos de la demanda externa y con rendimientos crecientes a escala, en la determinación de las diferencias en tasas de crecimiento regionales. Se demuestra la capacidad del enfoque para explicar la experiencia de crecimiento de Baja California en el largo plazo y se argumenta sobre la necesidad de considerar dichos factores para reorientar el patrón de especialización productiva del estado.

  2. A Stepped Wedge, Cluster-Randomized Trial of a Household UV-Disinfection and Safe Storage Drinking Water Intervention in Rural Baja California Sur, Mexico

    OpenAIRE

    Gruber, J. S; Reygadas, F.; Arnold, B. F; Ray, I.; Nelson, K; Colford, J.M.

    2013-01-01

    In collaboration with a local non-profit organization, this study evaluated the expansion of a program that promoted and installed Mesita Azul, an ultraviolet-disinfection system designed to treat household drinking water in rural Mexico. We conducted a 15-month, cluster-randomized stepped wedge trial by randomizing the order in which 24 communities (444 households) received the intervention. We measured primary outcomes (water contamination and diarrhea) during seven household visits. The in...

  3. Residential tourism and migration of foreign retirees in Mexico: A case study on the environmental impacts and public services in Baja California Sur

    OpenAIRE

    Diego Armando Casas-Beltrán; Luis Felipe Beltrán-Morales; Aradit Castellanos; Aurora Breceda Solís-Cámara

    2013-01-01

    Migration of foreign retirees in Mexico has increased, especially in Los Cabos, where settlements trailer type are increasing and are moving into rural coastal areas of high ecological value, without the knowledge of impacts that may result. Thus the aim of this paper is to contribute to the understanding of this type of settlement, by documenting a case study, the characteristics of their community, their environmental impacts and implications for the provision of public services. We conclud...

  4. Learning about Baja California Indians: Sources and Problems

    OpenAIRE

    Aschmann, Homer

    1986-01-01

    For the extinct but by no means forgotten Indians of the southern three-fourths of Baja California, there are three sources of data that can be used to construct a more accurate picture of the cultures that they developed in a difficult arid environment over many millennia. These are: (1) comparative studies of still surviving Indian neighbors to the north and also of hunters and gatherers in dry parts of the greater Southwest; (2) archaeological investigations, not only in the peninsula but ...

  5. Residential tourism and migration of foreign retirees in Mexico: A case study on the environmental impacts and public services in Baja California Sur

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    Diego Armando Casas-Beltrán

    2013-07-01

    Full Text Available Migration of foreign retirees in Mexico has increased, especially in Los Cabos, where settlements trailer type are increasing and are moving into rural coastal areas of high ecological value, without the knowledge of impacts that may result. Thus the aim of this paper is to contribute to the understanding of this type of settlement, by documenting a case study, the characteristics of their community, their environmental impacts and implications for the provision of public services. We conclude that the town will become a short-term retreat site, because while it does not have high densities, its environmental implications are significant and broad coverage. Its current demand for services is minimal, but may cause conflicts in the future, especially with the water

  6. A weather analysis system for the Baja California peninsula: tropical cyclone season of 2007

    Science.gov (United States)

    Farfan, L. M.; Cosio, M. A.

    2008-05-01

    General characteristics of tropical weather systems were documented on a real-time basis. The geographical area of interest is the Baja California peninsula, located in northwestern Mexico. This study covers the warm season of 2007, from May through October, and includes observations derived from radar and satellite imagery as well as reports from a network of rain gauges. A set of graphical products were generated and they were available to the public through the internet. The analysis system has been in operation since the summer of 2005 and it is focused to document the development of tropical cyclones in eastern Pacific Ocean. During the season of 2007, this basin had a total of 11 tropical storms and four of them were within 800 km from the west coast of Mexico (Dalila, Ivo, Juliette and Kiko). Only one system made landfall in the area of interest: Hurricane Henriette which moved across Baja California, the Gulf of California and a portion of the state of Sonora. This presentation provides an overview of the graphical products along with lessons learned from the season studied, collaborations with local emergency managers and plans for the upcoming season of 2008.

  7. A stepped wedge, cluster-randomized trial of a household UV-disinfection and safe storage drinking water intervention in rural Baja California Sur, Mexico.

    Science.gov (United States)

    Gruber, Joshua S; Reygadas, Fermin; Arnold, Benjamin F; Ray, Isha; Nelson, Kara; Colford, John M

    2013-08-01

    In collaboration with a local non-profit organization, this study evaluated the expansion of a program that promoted and installed Mesita Azul, an ultraviolet-disinfection system designed to treat household drinking water in rural Mexico. We conducted a 15-month, cluster-randomized stepped wedge trial by randomizing the order in which 24 communities (444 households) received the intervention. We measured primary outcomes (water contamination and diarrhea) during seven household visits. The intervention increased the percentage of households with access to treated and safely stored drinking water (23-62%), and reduced the percentage of households with Escherichia coli contaminated drinking water (risk difference (RD): -19% [95% CI: -27%, -14%]). No significant reduction in diarrhea was observed (RD: -0.1% [95% CI: -1.1%, 0.9%]). We conclude that household water quality improvements measured in this study justify future promotion of the Mesita Azul, and that future studies to measure its health impact would be valuable if conducted in populations with higher diarrhea prevalence.

  8. Future groundwater extraction scenarios for an aquifer in a semiarid environment: case study of Guadalupe Valley Aquifer, Baja California, Northwest Mexico.

    Science.gov (United States)

    Campos-Gaytan, Jose Ruben; Kretzschmar, Thomas; Herrera-Oliva, Claudia Soledad

    2014-11-01

    Semiarid northwestern Mexico presents a growing water demand produced by agricultural and domestic requirements during the last two decades. The community of Guadalupe Valley and the city of Ensenada rely on groundwater pumping from the local aquifer as its sole source of water supply. This dependency has resulted in an imbalance between groundwater pumpage and natural recharge. A two-dimensional groundwater flow model was applied to the Guadalupe Valley Aquifer, which was calibrated and validated for the period 1984-2005. The model analysis verified that groundwater levels in the region are subject to steep declines due to decades of intensive groundwater exploitation for agricultural and domestic purposes. The calibrated model was used to assess the effects of different water management scenarios for the period 2007-2025. If the base case (status quo) scenario continues, groundwater levels are in a continuous drawdown trend. Some wells would run dry by August 2017, and water demand may not be met without incurring in an overdraft. The optimistic scenario implies the achievement of the mean groundwater recharge and discharge. Groundwater level depletion could be stopped and restored. The sustainable scenario implies the reduction of current extraction (up to about 50 %), when groundwater level depletion could be stopped. A reduction in current extraction mitigates water stress in the aquifer but cannot solely reverse declining water tables across the region. The combination of reduced current extraction and an implemented alternative solution (such as groundwater artificial recharge), provides the most effective measure to stabilize and reverse declining groundwater levels while meeting water demands in the region.

  9. The Cooperativism and Agricultural Credit in Baja California, Mexico (1930-1950: A first approach El cooperativismo y la financiación agrícola en Baja California, México (1930-1950: Una aproximación inicial

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    Jesús Méndez Reyes

    2011-01-01

    Full Text Available In order to the neoclassic conventional theory the operation of the credit markets face two basic difficulties: the asymmetric or imperfect information and the adverse selection of the borrower come together with the nonpayment risk. On and other side, more heterodox, the collectivism, the social capital and the creation of informal nets and credit societies, use to low down the transaction costs related to the financing problem. This kind of organization makes easier the development of cooperativism in economy. In México, after the Revolution and the establishment of an authoritarian political and vertical regimen, the cooperativism became one of the referents of the rural organization in order to get credit of private and public banks. In the northeast of the country and Baja California peninsula, the existence of fishing, cattle raising, farming and transportation cooperatives means a blunt of economical activity and one of the channels of development in the zone. The purpose of this article is to shape what kind of cooperativism was set up in the Northern District of Baja California and what type of relation kept with the national cooperative movement between 1930 and 1950.Para la teoría neoclásica convencional el funcionamiento de los mercados de crédito soporta dos dificultades básicas: la información imperfecta o asimétrica y la selección adversa del prestatario aunada al riesgo del no pago. En el otro extremo, más heterodoxo, el colectivismo, el capital social y la formación de redes informales y sociedades de crédito suelen reducir los costes de transacción ligados al problema de la financiación. Este tipo de organización facilita el desenvolvimiento del cooperativismo en la economía. En México, después de la Revolución y la conformación de un régimen político autoritario y vertical, el cooperativismo se constituyó en uno de los referentes de la organización campesina para conseguir crédito de la banca pública y

  10. Some characteristics of the complex El Mayor-Cucapah, MW7.2, April 4, 2010, Baja California, Mexico, earthquake, from well-located aftershock data from local and regional networks.

    Science.gov (United States)

    Frez, J.; Nava Pichardo, F. A.; Acosta, J.; Munguia, L.; Carlos, J.; García, R.

    2015-12-01

    Aftershocks from the El Mayor-Cucapah (EMC), MW7.2, April 4, 2010, Baja California, Mexico, earthquake, were recorded over two months by a 31 station local array (Reftek RT130 seismographs loaned from IRIS-PASSCAL), complemented by regional data from SCSN, and CICESE. The resulting data base includes 518 aftershocks with ML ≥ 3.0, plus 181 smaller events. Reliable hypocenters were determined using HYPODD and a velocity structure determined from refraction data for a mesa located to the west of the Mexicali-Imperial Valley. Aftershock hypocenters show that the El Mayor-Cucapah earthquake was a multiple event comprising two or three different ruptures of which the last one constituted the main event. The main event rupture, which extends in a roughly N45°W direction, is complex with well-defined segments having different characteristics. The main event central segment, located close to the first event epicenter is roughly vertical, the northwest segment dips ~68°NE, while the two southeast segments dip ~60°SW and ~52°SW, respectively, which agrees with results of previous studies based on teleseismic long periods and on GPS-INSAR. All main rupture aftershock hypocenters have depths above 10-11km and, except for the central segment, they delineate the edges of zones with largest coseismic displacement. The two southern segments show seismicity concentrated below 5km and 3.5km, respectively; the paucity of shallow seismicity may be caused by the thick layer of non-consolidated sediments in this region. The ruptures delineated by aftershocks in the southern regions correspond to the Indiviso fault, unidentified until the occurrence of the EMC earthquake. The first event was relocated together with the aftershocks; the epicenter lies slightly westwards of published locations, but it definitely does not lie on, or close to, the main rupture. The focal mechanism of the first event, based on first arrival polarities, is predominantly strike-slip; the focal plane

  11. Water Bodies and Vegetation in the California-Baja California Border Region a Remote Sensors Perspective.

    Science.gov (United States)

    Hinojosa, A.; Mexicano-Vargas, M. L.; Serrato, B. A.

    2007-05-01

    The California-Baja California border region although they share watersheds, similar climate and landscape, there is a big contrast in the vegetation cover and water bodies between the two countries as seen from remote sensors. There is a stronger signature of vegetation and larger number of water bodies in the California side. To do a quantitative estimate of these differences, a comparative analysis of vegetation and water bodies was perfomerd along a strip of 100 km from both sides of the border with remote sensing techniques using Landsat TM images from 1984 to 2006. The strong absorption of water to short wave infrared radiation captured by band 5 of TM Landsat sensor (1.55- 1.75 micrometers) is use to detect water bodies. The histogram segmentation technique was used with TM 5/1 band ratios reinforced with a shades prediction technique using the sun position and a digital elevation model. The aerial extent of detected water bodies is estimated. Also an analysis from 1972 trough 2002 of the Mexican portion of Colorado river delta will be presented, with emphasis on flood events induced by abnormal snowmelts and higher precipitations in the high basin; 250 Landsat image previews were collected , from which 157 were selected to integrate 63 scenes that provide a dynamic picture of the Colorado delta river over 30 years. A regression with the annual averages of inundated areas and annual water flow data from E.U. to Mexico was made with a correlation coefficient of 0.912. The normalized difference vegetation index (NDVI) was used to estimate the vegetation greenness in the agricultural valleys and in natural vegetated areas along the mountains on both sides of the border. The spatial distribution of the NDVI and the differences between zones with the same land use regime on both sides of the border is presented.

  12. Bacteriological water quality along the Tijuana-Ensenada, Baja California, México shoreline.

    Science.gov (United States)

    Orozco-Borbón, Ma Victoria; Rico-Mora, Roxana; Weisberg, Stephen B; Noble, Rachel T; Dorsey, John H; Leecaster, Molly K; McGee, Charles D

    2006-10-01

    This survey was part of a Binational Program (Mexico-United States) in microbiological water quality, with a goal to assess the shoreline bacteriological water quality from Tijuana to Ensenada, Mexico. Samples were collected at 29 sites (19 beaches and 10 outfalls), from the United States border to Punta Banda, Baja California, during summer (1998) and winter (1999). Total coliforms, fecal coliforms and enterococci were used as bacterial indicators. Standard methods were used for total and fecal coliforms, while the Enterolert quick method (IDEXX) was used for the enterococci. Compared with outfalls, the beaches exceeded water quality standards by a small percent, 25.3% in summer and 17% in winter. For outfalls, the percentage of shoreline that exceeded bacterial indicator thresholds had a minor value in summer (32.7%) than in winter (50%). Sites near wastewater discharges had the lowest quality and did not meet the microbiological water quality criteria for recreational use.

  13. Jack Mosby en la revuelta de 1911 en Baja California

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    Lawrence Douglas Taylor

    2000-01-01

    Full Text Available En el presente artículo se analiza el papel que desempeñó el estadounidense John R. Mosby, conocido popularmente como Jack Mosby, en la revuelta de 1911 en Baja California encabezada por Ricardo Flores Magón y el Partido Liberal Mexicano. Mosby fue uno de los personajes más interesantes y controvertidos de esta campaña. Militar de profesión, también era miembro de los Industrial Workers of the World (Trabajadores Industriales del Mundo , una organización laboral radical de Estados Unidos que contribuyó a la defensa legal de los miembros de la junta dirigente del P L M, acusados por las autoridades estadounidenses de haber violado las leyes de neutralidad. Se examina la postura de Mosby a lo largo de la lucha, incluyendo las raíces de su apoyo entre los hombres de la Segunda División de los grupos armados liberales en la Baja California, su decisión de sostener los principios de Ricardo Flores Magón y del P L M, así como su determinación de continuar la lucha en la región aun cuando la derrota era casi inevitable.

  14. Recognition on space photographs of structural elements of Baja California

    Science.gov (United States)

    Hamilton, W.

    1971-01-01

    Gemini and Apollo photographs provide illustrations of known structural features of the peninsula and some structures not recognized previously. An apparent transform relationship between strike-slip and normal faulting is illustrated by the overlapping vertical photographs of northern Baja California. The active Agua Blanca right-lateral strike-slip fault trends east-southeastward to end at the north end of the Valle San Felipe and Valle Chico. The uplands of the high Sierra San Pedro Martir are a low-relief surface deformed by young faults, monoclines, and warps, which mostly produce west-facing steps and slopes; the topography is basically structural. The Sierra Cucapas of northeasternmost Baja California and the Colorado River delta of northwesternmost Sonora are broken by northwest-trending strike-slip faults. A strike-slip fault is inferred to trend northward obliquely from near Cabo San Lucas to La Paz, thence offshore until it comes ashore again as the Bahia Concepcion strike-slip fault.

  15. Manejo de un sitio de anidación para la conservación de Sternula antillarum (Charadriiformes: Laridae en Baja California Sur, México Nesting site management for Sternula antillarum (Charadriiformes: Laridae conservation in Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Edgar Amador

    2008-06-01

    Full Text Available El gallito marino menor (Sternula antillarum es una especie sujeta a protección especial, que anida en colonias pequeñas en hábitats costeros. Las mareas altas son un problema para la anidación de S. antillarum en Baja California Sur, pues causan la inundación de algunas colonias. Para reducir el impacto potencial del flujo de marea alta sobre los nidos, se elevó 20 cm el nivel del suelo por medio de una plataforma elevada construida con llantas de desecho rellenas y cubiertas de arena. La ocupación de este sitio por S. antillarum se monitoreó durante las temporadas reproductivas de 1990, y de 2002 a 2005. Las mareas altas no afectaron los nidos establecidos sobre la plataforma y la densidad de nidos sobre ella fue mayor que la que hubo en el terreno natural de la planicie costera adyacente. Este método de manejo del hábitat de anidación de S. antillarum es una buena alternativa en los sitios con riesgo por flujo de marea.The Least Tern (Sternula antillarum is a threatened seabird species that breeds in small colonies on coastal habitats. High tides constitute a problem for their reproduction in Baja California Sur, since they cause flooding of some colonies. To reduce the potential impact of high tides on the nests, the level of the ground was elevated by 20 cm, through an elevated platform that was built by using discarded tires filled and covered with sand. The occupation of this site by Least Terns was monitored during the breeding seasons of 1990 and from 2002 to 2005. High tides did not affect the nests established on the platform and density of nests on this platform was higher than on the natural adjacent mudflat area. This nesting habitat management method for the Least Tern is an appropriate alternative for those sites affected by high tides.

  16. Learning processes and productive modernization of learning in agriculture from northwestern Mexico: Cases of commercial agriculture of the coast of Hermosillo, Sonora and organic agriculture of the southern zone of Baja California Sur

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    Abel O. Villa Rodríguez

    2013-01-01

    Full Text Available The process of open markets has created import changes in the Mexican agriculture sector, very much noted in the so called crop pattern, the institutional frame that guides the agro–productive commercial relationships and trade organization. The agriculture in the Northwest region, particularly La Costa de Hermosillo in the State of Sonora and southern Baja in Baja Peninsula, shows a big transformation. This corresponds to Global Production Networks (gpn, a vertical integration with intensive extraterritorial interaction resulting in a process of productive escalation that favors; learning and the creation of new competitive capabilities indispensable to comply with high standards in international markets. These capabilities are reflected in improvements in product quality, productive efficiency and the development of new functions for the players involved in the production and trade of produce. It also reflects the transition to more sophisticated productive units where players are located in other territories. This study focuses on analyzing the roll of gpn in the transformation of the agricultural sector in the northwest region of Mexico, particularly the process that took place in modernizing both places.

  17. Desarrollo, identidad cultural y turismo en los oasis de Baja California Sur, México

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    Alexandra Sauvage

    2013-01-01

    Full Text Available This article provides an analysis of the integration of San Miguel and San José de Comondú to the process of economic globalization lived in Baja California Sur, in northwest Mexico. These rural communities are located in one of the largest oasis in the arid Baja California peninsula and face the risks of cultural commodification from the growth of the real estate and tourism sectors. In a context of diffuse integration to new markets and a weak local community involvement in the initiatives to foster economic growth, without a cultural policy that involves comundeños in defining their own heritage and the benefits of its use, the goal of local development attached to the recent public policies is questionable. We propose that a cultural policy should form the backbone of the development programmes now being elaborated, so as to articulate regional development needs with cultural heritage conservation, seeking to avoid the simple commodification of local traditions and recognizing the role of the local community in (redefining their cultural values.

  18. Politic alternation in Baja California: Toward a new balance of powers

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    Cuauhtémoc López Guzmán

    2001-01-01

    Full Text Available Ever since the National Action Party (PAN won the governor elections in the State of Baja California in 1989, Mexico experienced the inauguration of a political alternation in a governor’s office, which brought about the smashing of the myth that it was impossible for the PRI to share power at that level. The scarce forums won or surrendered by the party ever present in power, allowed the opposition to confront and criticize the centralization of power and the neutralization of representation, that is, rather than offering its voters nationalistic discourses, the opposition parties joined the cause of the anti-centralist resent, particularly present in the northern part of the country, and discredited the decaying relationship between the legislative and the executive powers (the presidency, both at a federal and states levels. In view of these considerations, the possibilities of setting the foundations for a new horizontal and vertical relationship among powers in the state of Baja California, which during the last ten years has been governed by the National Action Party, are discussed in this essay.

  19. Farallon slab detachment and deformation of the Magdalena Shelf, southern Baja California

    Science.gov (United States)

    Brothers, Daniel S.; Harding, Alistair J.; Gonzalez-Fernandez, Antonio; Holbrook, W.S. Steven; Kent, Graham M.; Driscoll, Neal W.; Fletcher, John M.; Lizarralde, Daniel; Umhoefer, Paul J.; Axen, Gary

    2012-01-01

    Subduction of the Farallon plate beneath northwestern Mexico stalled by ~12 Ma when the Pacific-Farallon spreading-ridge approached the subduction zone. Coupling between remnant slab and the overriding North American plate played an important role in the capture of the Baja California (BC) microplate by the Pacific Plate. Active-source seismic reflection and wide-angle seismic refraction profiles across southwestern BC (~24.5°N) are used to image the extent of remnant slab and study its impact on the overriding plate. We infer that the hot, buoyant slab detached ~40 km landward of the fossil trench. Isostatic rebound following slab detachment uplifted the margin and exposed the Magdalena Shelf to wave-base erosion. Subsequent cooling, subsidence and transtensional opening along the shelf (starting ~8 Ma) starved the fossil trench of terrigenous sediment input. Slab detachment and the resultant rebound of the margin provide a mechanism for rapid uplift and exhumation of forearc subduction complexes.

  20. The social representation of drug trafficking like laborer optionAt first glance, the State of Baja California (Mexico and the Department of Valle del Cauca (Colombia do not have much in common. They belong to different countries and have significant di

    Directory of Open Access Journals (Sweden)

    Lilian Paola Ovalle

    2010-11-01

    Full Text Available At first glance, the State of Baja California (Mexico and the Department of Valle del Cauca (Colombia do not have much in common. They belong to different countries and have significant differences in their history and their social, cultural, political and economic structures. However these places have a commonality--namely the fact that for more than three decades they have become epicenters of drug trafficking. In both of these territories, trafficking groups and international business networks have appropriated the region in order to frame their illegal project. This paper summarizes the findings of field research conducted during December 2008. Knowing and comparing the social representations of drug trafficking in these two territories, offers significant elements that help understand the integration processes and social penetration of drug trafficking in local contexts—and shed light on processes that have helped consolidate these practices as viable labor options.

  1. The surface expression of radiocarbon anomalies near Baja California during deglaciation

    Science.gov (United States)

    Lindsay, Colin M.; Lehman, Scott J.; Marchitto, Thomas M.; Ortiz, Joseph D.

    2015-07-01

    Periods of declining atmospheric radiocarbon activity (Δ14C) during the Heinrich 1 (∼17.8-14.6 ka) and Younger Dryas (∼12.8-11.5 ka) stadials of the last deglaciation coincide with intervals of rising atmospheric CO2, as well as evidence of 14C-depleted carbon at intermediate ocean depths near Baja California, Mexico and in the Arabian Sea. The latter has been interpreted as the signature of aged carbon emerging through the intermediate ocean to the atmosphere from a previously isolated deep ocean reservoir. Here we report measurements from near Baja California that enable us to reconstruct the Δ14 C of surface waters as recorded by three different species of planktonic foraminifera. We find that surface ocean Δ14 C recorded by planktonic foraminifera was anomalously low relative to the coeval atmosphere during previously documented periods of low benthic Δ14 C, consistent with upwelling and subsequent mixing and/or partial atmospheric equilibration of the intermediate-depth benthic signal. We also propose an oceanographic explanation for observed Δ14 C differences between individual planktonic species during deglaciation at this location, based on seasonal growth habitats and a seasonal change in the source of coastal upwelling waters: from northern in the spring to southern in late summer, as the shelf-trapped poleward California Undercurrent strengthens. An analysis of the contemporary hydrography and planktic habitat preferences suggests that G. bulloides and G. sacculifer record primarily springtime conditions off Baja California, when the local influence of waters sourced from the surface of the North Pacific is greatest. This is supported by the strong resemblance of the Δ14 C of those species and a recent record of planktic Δ14 C from the Northeast Pacific during deglaciation. Lower Δ14 C recorded by the late-summer species G. ruber suggests that locally upwelling waters carried 14C-depleted carbon that was proximately sourced from equatorial

  2. Vertebrados terrestres registrados mediante foto-trampeo en arroyos estacionales y cañadas con agua superficial en un hábitat semiárido de Baja California Sur, México Terrestrial vertebrates recorded by camera traps in areas with seasonal streams and creeks of superficial waters in a semiarid habitat of Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Erika Mesa-Zavala

    2012-03-01

    Full Text Available Los cuerpos de agua superficial (CAS permanentes o efímeros (pozas, tinajas, escurrimientos, etc. que se encuentran en depresiones del terreno, como arroyos y cañadas, son soporte fundamental para el ecosistema en zonas áridas. Mediante el uso de cámaras-trampa, en este estudio se identifican especies de vertebrados terrestres silvestres presentes en 4 sitios con agua superficial, en el extremo sur de la sierra El Mechudo, Baja California Sur, y se analiza el uso de los CAS por las especies en los periodos de actividad. En cada sitio se caracterizó el hábitat (topografía, vegetación y agua. Los 4 sitios mostraron diferencias en sus características ambientales. Se identificaron 41 especies de vertebrados terrestres (3 reptiles, 31 aves y 7 mamíferos. Se encontraron también varias especies de murciélagos que no fueron identificadas. La riqueza de especies y frecuencia de visita fue diferente en cada sitio. Con excepción de 3 especies de mamíferos, el horario de actividad fue similar en los 4 sitios. La presente investigación aporta información sobre la importancia de los CAS en zonas semiáridas, describiendo el hábitat, las especies y su comportamiento, elementos básicos para la conservación y manejo de los recursos naturales.Permanent or ephemeral water ponds (puddles, catchments, drains, and so on located on ground depressions, such as streams and creeks, are a fundamental support for ecosystems in dry areas. This study identified the species of native terrestrial vertebrates in 4 sites in the southernmost part of the Sierra El Mechudo, B.C.S., including how such species use these bodies of water based on the periods of species activity. Habitats were characterized in 4 sites (topography, vegetation, and water sources; camera-traps were placed around water ponds from March to October 2007. The 4 sites differed in their environmental characteristics. Overall, there were 41 species of terrestrial vertebrates (3 reptiles, 31

  3. Expresiones arquitectónicas compartidas en la frontera de Baja California y California

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    David Piñera Ramírez

    2011-01-01

    Full Text Available En este trabajo se analizan algunos factores significativos que han modelado la arquitectura y el diseño desde fines del siglo dieciocho y hasta el presente en la región que conforman los ámbitos fronterizos de Baja California y California. Se enfoca la atención en los estilos arquitectónicos victoriano y misional californiano con el señalamiento de la manera en que han sido compartidos por ambas entidades.

  4. Desarrollo humano en el noroeste de México: un análisis comparativo de los estados de Sonora, Baja California y Baja California Sur, 1995-2005

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    Francisco José Zamudio Sánchez

    2009-01-01

    Full Text Available Este artículo aborda el desarrollo humano en Sonora, Baja California y Baja California Sur. Se estimaron los valores de cuatro índices: desarrollo humano con producto interno bruto, desarrollo humano con servicios, con género e inequidad; además de curvas de calidad estatal y municipal.Aunque los valores ubican a Baja California Sur en la mejor posición de los indicadores de desarrollo humano y después a Sonora; Baja California ocupa el mejor sitio en equidad en el país.

  5. First Record of Fibropapillomatosis in a Green Turtle Chelonia mydas from the Baja California Peninsula.

    Science.gov (United States)

    Reséndiz, Eduardo; Flores-Ramírez, Sergio; Koch, Volker; Cordero-Tapia, Amaury

    2016-12-01

    Fibropapillomatosis (FP) is characterized by multiple fibroepithelial tumors in all parts of the skin and has been reported in sea turtles worldwide. Clinically infected individuals are often emaciated and anemic. In Mexico, however, there are few records of this disease. In this study of green turtles Chelonia mydas in Laguna San Ignacio in Baja California Sur (BCS), we noted one juvenile with multifocal fibropapilloma lesions on the external upper surface of its eyes and hind flippers. Light microscopy revealed hyperkeratosis, epidermal hyperplasia, dermal papillary projections, and fibroblast proliferation. Electron microscopy revealed viral particles. Biopsies of normal skin were done to determine the origin of the turtle through genetic analysis. Its mitochondrial DNA matched that of a haplotype (CMP2) from a Hawaiian green turtle population. Finding FP in a turtle captured in BCS elucidates the need for further monitoring along the west coast of Mexico. Further investigation should include testing tumors to detect and characterize any chelonid herpesviruses and explore any association with FP and other diseases that pose a health risk to other sea turtle species. Received March 26, 2016; accepted August 3, 2016.

  6. Marine reserves help preserve genetic diversity after impacts derived from climate variability: Lessons from the pink abalone in Baja California

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    Adrián Munguía-Vega

    2015-07-01

    Full Text Available Genetic diversity is crucial for the adaptation of exploited species like the pink abalone (Haliotis corrugata, faced with threats from climate change, overfishing and impacts associated with aquaculture production. While marine reserves are commonly used to mitigate risks to marine populations, the duration, size, location and larval connectivity needed for a reserve to help conserve genetic resources is still poorly understood. Here, we examine the effects of fishing, reserves, and restocking on the genetic diversity of 10 populations from central Baja California, Mexico, and Southern California, USA. We demonstrate that each population shows characteristic genetic signatures according to recent management decisions. We found high allelic diversity, particularly rare alleles, a larger effective population size and a lack of a recent genetic bottleneck in pink abalones within a small (0.8 km2, recently established (5 years reserve in Baja California, compared to other fished sites after a climatic bottleneck. Higher diversity may result from the presence of older animals in the reserve. Due to its location, the reserve may also act as an important hub connecting distant populations via larval dispersal. In contrast, a population from California showed genetic isolation, loss of allelic diversity and high relatedness, consistent with the collapse of fisheries in the 1990s and their lack of recovery thereafter. In addition, a fished area in Baja California with a history of restocking for over a decade showed an increase in frequency of related individuals and high genetic differentiation from nearby sites that were consistent with the production of larvae from a few adults in the laboratory. A network of strategically placed small marine reserves that considers ocean circulation patterns could help to maintain genetic diversity and connectivity of exploited populations.

  7. Gender and abuse: Partner violence among young people in Baja California

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    Humberto González Galbán

    2010-07-01

    Full Text Available Domestic violence or spousal abuse, largely determined by the existing traditional gender roles, is the issue discussed in this article, which is focusing on the special case of young people of the state of Baja California. During the search of the conditional agents of this social process, there were valued psychological and socio–demographic variables, such as family violence during childhood, immigration status, educational level and age, all these variables were separated by the gender and age (rank 18–29 of the sudied sample.Considering the information provided of the database used; The Survey of Adolescent Reproductive Health of Baja California 2006, it is described and analyzed in this research, several indicators, all of them related with important issues which affect a part of the young population of Baja California, regardless the lack of information and almost non previous research about this theme.

  8. Mujer y nación: una historia de la educación en Baja California. 1920-1930

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    María del Consuelo López Arámburo

    2005-01-01

    Full Text Available This article forms part of research in progress that aims to examine the intellectual climate prevailing in Mexico in the post-revolutionary period, from 1920 to 1930. The essay explores how the influence of nationalist ideology gradually shifted the role of Mexican women, identifying them as the educators of the nation. The study focuses on Baja California since educators, such as Josefina Rendón Parra (1885-1977, were an important example illustrating how nationalist ideology engineered women´s role in Mexico´s reconstruction. Education with a spiritual dimension was the key doorway through which women gained access to the modern era. In a society that had yet to grant them the right to vote, education was also the doorway through which women gained acceptance as citizens. Finally, this study proposes the remaking of history through the mythological discourses, such as the legends that were fashionable in that period.

  9. Seismic Images of Faulting and Fossil Subduction of the Southern Baja California Margins

    Science.gov (United States)

    Gonzalez, A.; Fletcher, J. M.; Lizarralde, D.; Kent, G. M.; Harding, A. J.; Holbrook, S.; Umhoefer, P. J.; Axen, G. J.; Gorman, A. R.

    2003-12-01

    From September to November 2002, a marine geophysics experiment was carried out, using 2 ships and onshore personell, recording deep MCS (Multichannel Seismics), wide angle, gravity, magnetic and bathymetric data. The main objective of this experiment is to better understand the continental breakup processes and the rifting of the Baja California Peninsula from Mexico mainland. An array of airguns with a total air volume of 8000 cu.in. was the seismic source and a 6000 km-long, 480-channel streamer was used to record the deep MCS data. This equipment was towed by the R/V Maurice Ewing. A series of stacked and migrated sections have been obtained, showing a number of noticeable structures. To the W of the line corresponding to the Pacific margin, the fossil trench is covered by recent sediments, that are part of the Magdalena Fan. Towards the E, near the slope break, the Tosco-Abreojos fault zone is clearly imaged, showing some extensional component. Further to the E, an old syncline is covered in erosive unconformity by recent sediments. In the eastern part of the section, a half-graben structure can be observed. Under this structure, a reflective zone can be interpreted as the mylonitic zone corresponding to a detachment. Some basement scarpments seem to be parallel faults to the semigraben master fault. Other normal faults in the sediments of the basin are synthetic and antithetic with it. The master fault probably is the continuation to the S of the Santa Margarita-San Lazaro fault, reported previously as a detachment in Santa Margarita and Magdalena islands. The seismic line in the Gulf of California margin begins at a conspicuous slope at the mouth of the La Paz Bay, and corresponds to the same strike-slip fault observed in Partida and Espiritu Santo islands. The rest of the line is characterized by numerous strike-slip and normal faults, producing strong bathymetric variations.

  10. Spatial variation of biomass of seaweed assemblages in the temperate-tropical transition zone of Baja California Peninsula, Mexico Variación espacial de la biomasa de macroalgas en una zona de transición templado-tropical en la Península de Baja California, México

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    Margarita Casas Valdez

    2008-08-01

    Full Text Available Biomass changes of seaweed assemblages in four locations in a temperate-tropical transition zone were analyzed between October 1996 and August 1997. Locations with lower temperature, a high index of upwelling, and high quantities of hard substrate presented the largest values of biomass of seaweed (El Cardoncito (7.2 kg m-2, and Las Boyitas (6.2 kg m-2 and the biggest quantity of species of temperate affinity. Conversely, El Datilito (0.366 kg m-2, with a higher temperature, no evidence of upwelling, sandy substrate, and located in protected shallow waters, presented the lowest values of biomass and the lowest proportion of temperate affinity seaweed. The PCA and similarity analysis showed a close relationship between El Cardoncito and Las Boyitas. El Datilito was categorized as independent location, while Chester Rock (4.3 kg m-2 displayed intermediate characteristics. The close relationship observed between the first two locations can be explained by the similarity of their high biomass and physiographic and environmental characteristics. El Datilito has very different physiographic and environmental characteristics and a very low biomass.Se analizaron los cambios en la biomasa de las asociaciones de macroalgas en una zona de transición templado-tropical entre octubre de 1996 y agosto de 1997 en cuatro localidades. Las localidades con la temperatura más baja, alto índice de surgencias y mayor dominancia de sustrato duro presentaron los mayores valores de biomasa de macroalgas (El Cardoncito (7.2 kg m-2 y Las Boyitas (6.2 kg m-2 y la mayor cantidad de especies de afinidad templada. Por el contrario El Datilito (0.366 kg m-2 en donde la temperatura fue más alta, no hay evidencia de surgencias, el sustrato es arenoso, es un área más somera y protegida, presentó el menor valor de biomasa de macroalgas y la menor proporción de algas de afinidad templada. Los análisis de componentes principales y similaridad mostraron una estrecha relaci

  11. Seasonal changes in a fish assemblage associated with mangroves in a coastal lagoon of Baja California Sur, Mexico Cambios estacionales de la comunidad de peces asociada a zonas de manglar en una laguna costera de Baja California Sur, México

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    Jesús Rodríguez-Romero

    2011-07-01

    Full Text Available The fish assemblage in a coastal lagoon with mangroves known as "Rancho Bueno" was determined and associated with environmental parameters. We used an experimental otter trawl net to catch the fish, and 62 fish species were identified from 48 genera and 30 families. The most abundant species were: Etropus crossotus, Eucinostomus gracilis, Paralabrax maculatofasciatus, Sphoeroides annulatus, and Eucinostomus dowii. The water temperature changed seasonally, being warm from July through December and cold from January through June. We found more fish species during the warm season than during the cold season. The southern area of the coastal lagoon had the highest diversity and species richness. The small size of the fishes registered confirms the ecological role of coastal lagoons as nursery areas that offer protection and feeding to commercially important fish near Bahía Magdalena, Mexico.Se determinó la estructura de peces asociada a factores ambientales en una laguna costera con manglar denominada "Rancho Bueno". Se utilizó una red de arrastre experimental para la captura y se identificaron 62 especies de peces de 48 géneros y 30 familias. Las especies más importantes fueron Etropus crossotus, Eucinostomus gracilis, Paralabrax maculatofasciatus, Sphoeroides annulatus y Eucinostomus dowii. La temperatura del agua varió estacionalmente, siendo cálida de julio a diciembre y fría de enero a junio. Se registró un mayor número de especies de peces durante la época cálida comparada con la época fría. La zona sur de la laguna costera presentó una mayor diversidad y riqueza específica. El menor tamaño de los peces registrados, confirma el papel ecológico de las lagunas costeras, consideradas como áreas de crianza las cuales proporcionan protección y alimentación a los peces de importancia comercial cerca de Bahía Magdalena, México.

  12. Wines of Baja Mexico: A qualitative study examining viticulture, enology, and marketing practices

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    Jorge Covarrubias

    2015-12-01

    Full Text Available Mexico has been producing wine since the 1500, yet very little is known about their viticulture, enology, and marketing practices. This qualitative research study was designed to shed more light on these issues. Based on 10 in-depth interviews with winery owners and winemakers in the Valle de Guadualupe of the Baja Peninsula, where the majority of Mexican wineries are located, this study describes viticulture, enology, and marketing practices for Baja wines. It concludes with a discussion on the future of Mexican wines.

  13. Productividad secundaria en los esteros de la barra de arena El Mogote en la Ensenada de La Paz, Baja California Sur, México Secondary productivity in the estuaries of El Mogote sand bar in Ensenada de La Paz, Baja California Sur, Mexico

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    Jorge A. López-Rocha

    2012-04-01

    bivalve mollusks chosen as indicators of secondary productivity were the mangrove cockle Anadara tuberculosa and the mangrove oyster Crassostrea palmula. Samples were collected in three estuaries from August 2007 to July 2009. Abundance and secondary production were estimated from biomass increase, calculated from individual growth rates determined using length frequency distributions analysis. The average abundance was 1.27 and 510 ind · m-2 of mangrove cockle and mangrove oyster respectively. It was estimated a growth rate of 4.91 mm · month-1 (3.67 g · month-1 for mangrove cockle and 3.80 mm · month-1 (0.18 g · month-1 for the mangrove oyster. The mean secondary production of mangrove cockle was 4.51 g · m-2 · month-1 and was higher during spring, while for the mangrove oyster it was 97.9 g · m-2 · month-1, and the maximum production was recorded during summer. The results show that these indicators of benthos quality are suitable for measuring changes of the mangrove system in the Ensenada of La Paz, B. C. S., Mexico.

  14. Relationshipe Between Self-potential Anomalies and Hydraulic Flow In A Geothermal System: Application To Cerro-prieto, Baja California

    Science.gov (United States)

    Saracco, G.; Revil, A.; Pessel, M.

    The Cerro Prieto geothermal field is located in the alluvial plain of the Mexicali Valley, northern Baja California, Mexico, at about 35 km southeast of the city of Mexicali. The Cerro Prieto geothermal field is one of several high temperature water-dominated geothermal fields within the Salton Trough. We analyze here the self-potential distri- bution at the ground surface in order to determine the pattern of fluid flow in te sub- surface of this geothermal field. Various methods of analysis of self-potential anoma- lies are employed to reach this purpose. We use density probability tomography of monopolar and dipolar electrical sources and an Euler-type analysis. The hydraulic flow pattern found in this geothermal field is in agreement with that detemined from the heat flux inside the structure.

  15. Los concheros de Baja California y sus perspectivas de investigación

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    Agustín Téllez Duarte

    1987-09-01

    Full Text Available El presente artículo pretende enfatizar sobre la presencia de conchas en sitios arqueológicos, los cuales nos proporcionan una gran cantidad de información cultural sobre los asentamientos humanos, particularmente en los concheros de Baja California. En Baja California se localizan en forma intermitente a todo lo largo de sus costas, tanto en el golfo de California como en el Pacífico. Con este proyecto se pretende rescatar aquellas colecciones que aún puedan conservarse, considerando que las excavaciones de Palmer fueron muy productivas a pesar de haber sido relativamente pequeñas. Se espera que este primer intento de excavación arqueológica-científica de un conchero proporcione datos relevantes para comprender más ampliamente la organización de las antiguas sociedades humanas de Baja California, antes de que se pierdan totalmente los testimonios legados. Y a su vez, motive un mayor interés y apoyo en el estudio de los casi ignorados concheros.

  16. Baja California dentro del contexto de la migración de la frontera norte de México

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    Margarita Barajas Tinoco

    1993-01-01

    Full Text Available En este trabajo se destaca el papel del fenómeno migratorio en la conformación poblacional de la frontera norte de México (PNM en general y de Baja California en particular. Se describe el panorama de la inmigración interna a Baja California, haciendo especial énfasis en el perfil de la inmigración de la década de los ochenta, misma que se encuentra asociada con las oportunidades económicas de empleo que la entidad presentó en un periodo de crisis nacional. Las fuentes de información utilizadas son el Censo de Población, 1990, para Baja California y La Encuesta Continua de Migración de Baja California (ECMBC, 1989

  17. Migración y estructuración territorial del estado de Baja California

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    Alba Adriana Wells Ayón

    1990-05-01

    Full Text Available En este ensayo se considera a Baja California como un producto territorial del fenómeno migratorio, y se realiza una descripción general de la dinámica poblacional que ha experimentado el estado a partir de los constantes movimientos migratorios en destacadas áreas de su espacio geográfico. Demostrando así la existencia en Baja California de movilidades geográficas de población constituidas principalmente por tres tipos de movimientos: el interno, el interurbano, y el internacional; además de encontrar la presencia de cadenas de migración interna basadas en sistemas de reciprocidad social. Finalmente, se proporcionan las conclusiones del trabajo.

  18. Llegar a viejo en la frontera norte: El envejecimiento demográfico en Baja California

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    Elmyra YBÁÑEZ ZEPEDA

    2013-01-01

    Full Text Available En este artículo se analiza el envejecimiento demográfico en el estado de Baja California y en sus cinco municipios en el período 2000-2010. Se utiliza la información de los censos de 2000 y 2010 para caracterizar las estructuras demográficas, así como las proyecciones de población del Consejo Nacional de Población (Conapo para examinar el comporta- miento futuro de los principales indicadores demográficos. Los resultados revelan que el número de los mayores de 60 años se incrementa a gran velocidad por lo que se requiere planificar, desde ahora, el tipo de envejecimiento poblacional que la sociedad de Baja California desea tener.

  19. Geochemical survey of medium temperature geothermal resources from the Baja California Peninsula and Sonora, México

    Science.gov (United States)

    Barragán R, R. M.; Birkle, P.; Portugal M, E.; Arellano G, V. M.; Alvarez R, J.

    2001-09-01

    Waters from hot springs and deep wells from Cerritos in the northern Baja California Peninsula and deep wells from the Riı´to zone (Sonora state) were studied in order to classify medium temperature geothermal resources to be exploited in NW-Mexico. Geochemical characteristics of San Felipe and Punta Estrella coastal springs indicate the mixing of seawater and meteoric components with secondary leaching of evaporates. Reservoir temperatures for both zones were estimated up to 225°C. Mixing of high portions of seawater (>80 wt%) with local waters could be the origin for the Puertecitos coastal spring, with a reservoir temperature estimation of 195°C. The El Coloradito coastal spring is composed of meteoric water with a reservoir temperature of 127°C. The formation of thermal manifestations along the Baja California coast could be related to the heating up of convecting seawater along extensional tectonic structures, as observed for submarine hydrothermal vents at the Gulf of California and along the East Pacific Rise. Volcanic steam-heated waters with a reservoir temperature of 135°C were found at the Valle Chico inland springs from the Baja California Peninsula. Deep fluids from the Riı´to zone originated by evaporation of infiltrated waters with similar characteristics to those located in the Mexicali Valley. Reservoir temperature of 192 and 126°C are estimated for the Riı´to deep wells ER-1B (ER) and R-1, respectively. The Riı´to artesian wells M-1, M-2 and M-4 indicate reservoir temperatures from 109 to 118°C. Isotopic data define the artesian wells as typical surface water or shallow groundwater from the Mexicali Valley. The Cerritos deep fluids of the Mexicali Valley show a close chemical and isotopic relationship to the adjacent Cerro Prieto reservoir fluids suggesting a similar origin and a possible connection of both aquifer systems. Conductive cooling of Cerro Prieto discharge fluids could originate the cooler Cerritos system (130

  20. Sector externo, crecimiento económico y bienestar en Baja California: 1970-1988

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    Jorge García Montaño

    1990-05-01

    Full Text Available El presente trabajo tiene el objetivo de presentar los efectos del desarrollo del sector externo de Baja California en el crecimiento de la economía local y en relación con algunos indicadores del bienestar social. También se estudian algunos indicadores nacionales comparativos entre la entidad y los promedios nacionales, tal que permitan ubicar las especificidades del desarrollo de Baja California. El trabajo se divide en varios apartados: ciclos económicos, comportamiento del sector externo y sus relaciones con el producto interno bruto y la inflación. Todas estas variables interactúan en este estudio macroeconómico regional.La conclusión, hace referencia a que en Baja California el sector externo cumple el papel determinante para el crecimiento económico y el bienestar social; por lo tanto, cualquier trastorno negativo en sus variables desagregadas impacta inmediatamente las tasas de crecimiento y los niveles de vida de la población bajaca1iforniana, fundamentalmente los cambios extraordinarios del tipo de cambio peso-dólar y los ajustes de las políticas en comercio exterior. De ahí la actualidad del estudio, dado que el Tratado de Libre Comercio de México con Estados Unidos y Canadá tendrá, seguramente, importantes impactos en la entidad.

  1. Una mirada hacia las organizaciones civiles de apoyo al migrante en Baja California y Sonora

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    José Ascensión Moreno Mena

    2013-01-01

    Full Text Available Los migrantes en tránsito, los que intentan cruzar y los devueltos de Estados Unidos, que son presa de todo tipo de autoridad y del crimen organizado, demandan mucha atención, que no es brindada debidamente por el sector gubernamental. Ante tal situación, la sociedad civil organizada en Baja California y Sonora ha tenido que asistir a los deportados y aspirantes a ingresar al vecino país, incluyendo la promoción y defensa de los derechos humanos y la conformación de redes formales e informales. Baja California, debido a su larga experiencia en el tránsito de migrantes, está mejor preparado para atenderlos en cuanto a equipos e infraestructura física y humana no gubernamental. Los datos presentados son resultado de una encuesta aplicada a 21 de las 23 organizaciones civiles existentes en Baja California y a 9 de las 11 en Sonora.

  2. Alternativas de control en la pudrición radical de cebolla para el Valle de la Trinidad, Baja California Control Alternatives for Onion root rot in the Trinity Valley, Baja California

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    Armando Pulido-Herrera

    2012-02-01

    Full Text Available La pudrición radical en cebolla es la enfermedad más importante en el Valle de la Trinidad, Baja California, México. Con el propósito de evaluar estrategias de control para la enfermedad se realizaron tres experimentos durante 2007, 2008 y 2009. En el experimento I (2007 los tratamientos fueron: 1 Tiofanato metílico; 2 Smicobac (Trichoderma + Bacillus sp. + Azospirillum sp. + Pseudomonas sp.; 3 estiércol de bovino (EB; 4 residuos de cebolla (RC; 5 solarización plástico transparente (SPT, 6 solarización plástico negro (SPN; 7 SPT + EB; 8 SPT + RC; 9 SPN + EB; 10 SPN + RC; 11 Trichodef (Trichoderma harzianum;y 12testigo. En el experimento II (2008, los tratamientos fueron los mismos excepto el tratamiento 2, sustituido porprotector (extractos vegetales; y en el experimento III (2009 los tratamientos fueron: 1 SPT + estiércol de ovino (EO; 2 SPN + EO; 3 SPT; 4 SPN; 5 control biológico (Trichoderma spp.; y 6 control químico (2- (tiocianometiltio benzotiazol 30%. Los resultados indicaron que los tratamientos solarización plástico transparente con o sin enmiendas orgánicas, presentaron incrementos significativos (p≤ 0.05 de 22 a 34% en el rendimiento y diámetro del bulbo con respecto al control biológico y químico; sin embargo, en estos dos últimos tratamientos la incidencia y severidad se redujo significativamente (p≤ 0.05, por lo que la solarización con plástico transparente y el control biológico, son alternativas viables para el control de la pudrición radical en cultivos de cebolla en Baja California, México.Onion's root rot is the most important disease in the Trinidad Valle, Baja California, Mexico. In orderto evaluate strategies to control this disease, three experiments were conducted during 2007, 2008 and 2009. In experiment I (2007 the treatments were: 1 Thiophanate methyl; 2 Smicobac (Trichoderma+Bacillus sp. + Azospirillum sp. + Pseudomonas sp.; 3 cattle manure (EB; 4 waste of onion (RC; 5 clear plastic

  3. in the U.S.-Mexican Border: A Comparative Analysis of Calexico, California and Mexicali, Baja California

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    Kimberly Collins

    2007-01-01

    Full Text Available A lo largo de la frontera EUMéxico, existen problemas en ambos lados que confrontan los gobiernos locales. Ejemplos de estos hechos incluyen inmigración y políticas de seguridad; crecimiento de la población descontrolado que obedece al desarrollo económico; la falta de planeación urbana e infraestructura. Este documento revisa estos problemas mediante un análisis de federalismo en las ciudades hermanas de Calexico, California y Mexicali, Baja California.

  4. Neogene sedimentary evolution of Baja California in relation to regional tectonics

    Science.gov (United States)

    Helenes, J.; Carreño, A. L.

    1999-11-01

    During the Neogene, the tectonic and sedimentary evolution of the Baja California Peninsula followed four stages: (1) during the early Miocene (22 Ma), the initiation of transform motion between Pacific and North American plates, caused a rapid subsidence in the Continental Borderland Province and in some adjacent areas.This subsidence coincided in time with with a global rise in sea level. At this time, the eastern and southern parts of the peninsula did not show any evidence of subsidence. (2) During the middle Miocene (12 Ma), normal and strike slip faulting migrated eastward, causing subsidence in the northern part of the Gulf of California, where the oldest Tertiary marine sedimentary rocks were deposited. The areas in central Baja California Sur and the central part of the Gulf itself received abundant volcanic deposits related to continental extension. (3) During the late Miocene (8 Ma), the western margin of the Peninsula changed to a slightly compressive regime, while the northern part of the Gulf contained a marine basin with upper bathyal environments. The central area of the Gulf continued receiving abundant volcanic deposits, while the Los Cabos block received marine sedimentation, correlatable with sedimentary units reported from the continental margins in Nayarit, Jalisco and Michoacán. (4) Beginning in the early Pliocene (5 Ma), the present configuration of the Gulf of California developed through right-lateral strike slip and extension in the Gulf itself. Since Pliocene times, the Gulf presents widespread marine sedimentation with deep basins reaching lower bathyal depths.

  5. Status of the California Red-legged Frog (Rana draytonii) in the State of Baja California, México

    Science.gov (United States)

    Peralta-Garcia, Anny; Hellingsworth, Bradford D.; Richmond, Jonathan Q.; Valdez-Villavicencio, Jorge H.; Ruiz-Campos, Gorgonio; Fisher, Robert N.; Cruz-Hernandez, Pedro; Galina-Tessaro, Patricia

    2016-01-01

    The California Red-legged Frog (Rana draytonii) is a threatened species in the United States that has undergone population declines, especially in southern California. Due to the lack of information on the status of Mexican populations, we surveyed for the presence of R. draytonii in Baja California and assessed possible threats to population persistence. Our study area extended from the U.S.-Mexican border to the southern end of the distribution of the species in the Sierra San Pedro Mártir. We found R. draytonii at six of 15 historical sites, none at five proxy sites (i.e., alternative sites chosen because the historical record lacked precise locality data), and four at 24 additional sites. The 10 occupied sites are within three watersheds in the Sierra San Pedro Mártir (two sites at Arroyo San Rafael, two sites at Arroyo San Telmo, and six sites at Arroyo Santo Domingo). We did not detect R. draytonii at 60% of historical sites, including the highest elevation site at La Encantada and multiple low-elevation coastal drainages, suggesting the species has declined in Baja California. The threats we noted most frequently were presence of exotic aquatic animal species, water diversion, and cattle grazing. Management of remaining populations and local education is needed to prevent further declines.

  6. Hypoxic cyclicity in sediments of Soledad Basin, Baja Mexico: A record of high-frequency climate fluctuations?

    Science.gov (United States)

    Westman, A. E.; Brooks, G. R.; Lea, C.

    2007-05-01

    The sedimentary record in Soledad Basin, 45 km west of Baja, Mexico, shows high-frequency oscillations in hypoxia, which can be linked to fluctuations in climate. Soledad Basin, a semi-enclosed basin with a sill depth of 290m, has been shown to exhibit variable levels of hypoxia throughout the geologic past. Located at the intersection of the California Current and California Undercurrent, Soledad Basin is highly responsive to changes in current strength and upwelling, the combination of which creates fluctuations in hypoxia. During climatic cool periods, the California Current is weakened decreasing upwelling and biologic productivity along the Baja Borderland. This causes increased hypoxia in Soledad Basin. The California Undercurrent is also weakened during these cooler periods and brings less nutrients and oxygen to the basin further increasing hypoxia. Since Soledad Basin sediments are undisturbed and have accumulated rapidly, this is a prime location to study high frequency variations in hypoxia in the sedimentary record. The objective of this study was to examine how and to what extent hypoxic events have been recorded in the sedimentary record of Soledad Basin, and gain insight into what controls these events. Surface sediment samples and a single 1.1m gravity core were collected aboard the S.S.V. Robert C. Seamans on a SEA Semester cruise in October 2005. The core was taken at a depth of 490 m near the deepest point of the basin. The core contained laminated sediments consisting of >95% mud. Using 210Pb analysis, a sedimentation rate of 15 cm over the past 100 years was determined, which is consistent with previous research. Trace metal analyses were performed at the cm-scale on selected intervals between 0.34-0.44m and 0.78-0.92m. These intervals correspond to dark organic-rich (>15% organic content) laminations alternating with lighter layers containing less organic material (<15% organic content). All sediments were found to be enriched in Molybdenum

  7. Movilidad de población y comportamiento reproductivo: El caso de Baja California

    Directory of Open Access Journals (Sweden)

    Gabriel Estrella Valenzuela

    1992-09-01

    Full Text Available Este trabajo tiene como objetivo central evaluar el impacto indirecto que genera la inmigración hacia Baja California a través del comportamiento reproductivo de la población que, al migrar, ha cambiado su residencia habitual a la entidad. Para lograr ese objetivo, se analiza la información de las Encuestas Demográficas de Baja California de 1986 y 1990 con el modelo de los determinantes próximos de la fecundidad. Los resultados de dicho análisis muestran, por una parte, que los patrones reproductivos de la población migrante y no-migrante son c1aramentediferenciados (tanto en términos de fecundidad ilegítima como de formación de uniones, de sus prácticas anticonceptivas y de lactancia postparto, y que de ello se deriva un diferencial de fecundidad que resulta ser 17.5% superior para la población migrante en 1990. Por otra parte, los resultados también permiten estimar que, por cada tres nuevos inmigrantes que por año recibe la entidad, la inmigración acumulada aporta dos nuevos residentes con los nacimientos generados por las mujeres migrantes. Dada la magnitud que adquieren esos procesos (i.e. 59 mil nuevos habitantes por año ~ total, se concluye sugiriendo líneas generales de acción que permitan adecuar la política de población a las condiciones específicas de Baja California

  8. AVIFAUNA DEL ESTERO DE PUNTA BANDA, BAJA CALIFORNIA, MÉXICO

    OpenAIRE

    Luis C. JIMÉNEZ PÉREZ; Horacio de la CUEVA; Fernando MOLINA-PERALTA; Arnulfo ESTRADA-RAMÍREZ

    2009-01-01

    Entre marzo de 2004 y marzo de 2005 se realizaron veinticuatro salidas de campo quincenales de avistamiento y registro de aves costeras en 6 unidades ambientales del Estero de Punta Banda, Baja California, México. Se registraron 35 familias y 104 especies; 64 estuvieron asociadas al ambiente acuático. La estructura de las comunidades de aves acuáticas y terrestres presentó una secuencia temporal que se caracterizó por la formación de dos grupos asociados con las condiciones de invierno o vera...

  9. GANADERÍA OVINO - CAPRINA EN EL MARCO DEL PROGRAMA DE DESARROLLO RURAL EN BAJA CALIFORNIA

    OpenAIRE

    JA Martínez-Partida; L Jiménez-Sánchez; JG Herrera-Haro; E Valtierra-Pacheco; E Sánchez-López; MC López-Reyna

    2011-01-01

    . El desempeño productivo de la ganadería ovino-caprina en Baja California fue evaluado mediante la aplicación de una encuesta directa a 54 ovinocaprinocultores (OVCA) que recibieron apoyos del Programa de Desarrollo Rural (PDR) en el periodo 2000-2004, distribuidos en los municipios de Mexicali, Ensenada, Tecate y Tijuana. Fueron seleccionados mediante un diseño de muestreo estratificado con asignación proporcional. Las entrevistas personales incluyeron aspectos zootécnicos en reproducción, ...

  10. La interdependencia estructural entre el estado y la prensa en Baja California (1989-1995)

    OpenAIRE

    Ortiz Marín, Ángel Manuel

    2006-01-01

    Dentro del estudio de los fenómenos de comunicación social, se ha analizado y discutido, desde distintos enfoques teóricos, los procesos de mediación entre Poder, Estado y los medios de comunicación masiva. En noviembre de 1989 en Baja California, México, tomó posesión Ernesto Ruffo Appel (ERA) como gobernador de la entidad. En lo particular del caso bajacaliforniano es importante ya que por primera ocasión en casi 70 años en la historia moderna de México, mediante un proceso democrático, arr...

  11. Una mirada hacia las organizaciones civiles de apoyo al migrante en Baja California y Sonora

    OpenAIRE

    José Ascensión Moreno Mena; Lya Niño Contreras

    2013-01-01

    Los migrantes en tránsito, los que intentan cruzar y los devueltos de Estados Unidos, que son presa de todo tipo de autoridad y del crimen organizado, demandan mucha atención, que no es brindada debidamente por el sector gubernamental. Ante tal situación, la sociedad civil organizada en Baja California y Sonora ha tenido que asistir a los deportados y aspirantes a ingresar al vecino país, incluyendo la promoción y defensa de los derechos humanos y la conformación de redes formales e informale...

  12. Prensa y nacionalismo en Baja California durante la Segunda Guerra Mundial

    OpenAIRE

    2013-01-01

    El propósito de este trabajo es explicar algunas representaciones periodísticas del Territorio Norte de la Baja California. El corpus de textos que componen el presente artículo documentará diferentes versiones sobre el pasado de la península desde la naturaleza discursiva del lenguaje político. Los bajacalifornianos aparecerán representados por los periodistas, luchando por erradicar la imagen de un lugar aislado, deshabitado y lleno de estadunidenses. El discurso editorial de la prensa de T...

  13. Atención prenatal y mortalidad materna hospitalaria en Tijuana, Baja California

    OpenAIRE

    María Rode Gonzaga-Soriano; Abraham Zonana-Nacach; María Cecilia Anzaldo-Campos; Asbeidi Olazarán-Gutiérrez

    2014-01-01

    Objetivo. Describir la atención médica prenatal recibida en mujeres con mortalidad materna hospitalaria en el IMSS durante 2005-2012 en Tijuana, Baja California, México.Material y métodos. La información se obtuvo de los archivos de los Comités de Mortalidad Materna y revisión del expediente. Resultados. Hubo 44 muertes maternas (MM). Treinta (68%) asistieron a atención prenatal (AP), el promedio de citas fue de 3.8 y 18 (41%) tuvieron una AP adecuada ( 5 citas). Seis (14%) mujeres no...

  14. Encadenamientos intersectoriales de la industria maquiladora de exportación en Baja California

    Directory of Open Access Journals (Sweden)

    Noé Arón Fuentes

    2009-01-01

    Full Text Available Este artículo investiga la estructura de encadenamientos hacia atrás en la economía de Baja California, mediante un conjunto de técnicas para identificar sectores clave en un modelo de insumoproducto (MIP abierto y cerrado. En particular, el estudio se centra en el análisis de la relación tanto entre la incorporación de insumos nacionales y la promoción de la industria maquiladora de exportación (IME, como entre el crecimiento económico regional y encadenamientos hacia atrás.

  15. Commercial Whaling, Especially for Gray Whales, Eschrichtius robustus, and Humpback Whales, Megaptera novaeangliae, at California and Baja California Shore Stations in the 19th Century (1854–1899)

    OpenAIRE

    2010-01-01

    Shore whaling along North America’s California and Baja California coasts during 1854–99 was ancillary to the offshore and alongshore American whale fishery, which had begun in the North Pacific in the early 1800’s and was flourishing by the 1840’s. From its inception at Monterey, Calif., in the mid 1850’s, the shore fishery, involving open boats deployed from land to catch and tow whales for processing, eventually spread from Monterey south to San Diego and Baja California and north...

  16. Seismotectonics of the Cerro Prieto Geothermal Field, Baja California, Mexico.

    Science.gov (United States)

    Rebollar, C. J.; Reyes, L. M.; Quintanar, L.; Arellano, J. F.

    2002-12-01

    We studied the background seismic activity in the Cerro Prieto geothermal field (CPGF) using a network of 21 digital stations. Earthquakes are located below the exploitation area of the CPGF, between 3 and 12 km depth, within the basement. Earthquakes follow roughly a N30°E trend perpendicular to the Cerro Prieto fault. This activity is located on a horst-like structure below the geothermal field and coincides with the zone of maximum subsidence in the CPGF. Two earthquake swarms occurred along the SE-NW strike of the Cerro Prieto fault and in the neighborhood of the Cerro Prieto volcano. Magnitudes range from -0.3 to 2.5. A Vp/Vs=1.91 ratio of the activity below the volcano suggests a water-saturated medium and/or a partial-melt medium. We calculated 76 focal mechanisms of individual events. On June 1 and September 10, 1999, two earthquakes of Mw 5.2 and 5.3 occurred in the basement at depths of 7.4 and 3.8 km below the CPGF. Maximum peak accelerations above the hypocenter ranged from 128.0 to 432.0 cm/s2. Waveform modeling results in a fault geometries given by strike=236°, dip=60°, rake=-58° (normal) and strike=10°, dip=90°, rake=159° (right lateral strike-slip) for the June and September events. Observed triangular source time function of 0.7 seconds and a double source with a total duration of 1.9 seconds for the June and September events were used to calculate the synthetics seismograms. Static stress drops and seismic moments for the June and September events are: Δ\\sigma=82.5 MPa (825 bars), Mo= 7.65x1016 Nm (7.65x1023 dyne-cm) and Δ\\sigma=31.3 MPa (313 bars) and Mo=1.27x1017 Nm (1.27x1024 dyne-cm). These stress drops are typical of continental events rather than stress drops of events originated in spreading centers. We concluded from the focal mechanisms of the background seismicity and June and September 1999 events, that a complex stress environment exits in the CPGF due to the continual thinning of the crust in the Cerro Prieto basin.

  17. Algunos geosímbolos de Baja California. Identidad y memoria colectiva de la ruralidad

    Directory of Open Access Journals (Sweden)

    Alberto Tapia Landeros

    2009-01-01

    Full Text Available Este documento presenta una descripción de algunos lugares de Baja California que históricamente han sido nombrados por el ser humano nativo y colono en virtud de su utilidad como orientadores al viajar, porque poseen agua, han sido testigos de algún hecho relevante, son mencionados por motivos religiosos, reconocidos en cultos indígenas, destacados por razones políticas y cualquier otra causa para asignarles un significado simbólico. El conocimiento de estos sitios se ha obtenido a través de investigación documental y registros orales, en visitas de campo y mediante entrevistas con la población del lugar. También acudiendo a la antropología, historia, geografía y biología, entre otras disciplinas. La descripción de estos geosímbolos se analiza a la luz de las llamadas "razones" de Jöel Bonnemaison, de quien se tomó la definición, así como la idea de "nombrar es conocer, es crear" de Guillermo Bonfil. Se localizan los sitios mediante sus coordenadas en un mapa del estado de Baja California y se discute su ubicación.

  18. Pacientes pediátricos con VIH/sida en Baja California, México. Alteraciones bucales relacionadas

    OpenAIRE

    Anitza Domínguez Sánchez; Roberto de Jesús Verdugo Díaz; Luis Alberto Gaitán Zepeda; Ricardo Manuel Sánchez Rubio Carrillo; Ana María Valles Medina

    2011-01-01

    Antecedentes: Baja California, México, ocupa el cuarto lugar nacional en casos reportados de VIH/sida. Por ser los pacientes pediátricos la población más vulnerable, el odontólogo debe diagnosticarlos y canalizarlos oportunamente para una adecuada atención. Objetivo: describir las alteraciones dentales y de mucosa oral asociadas más frecuentes en pacientes pediátricos con diagnóstico de VIH/sida en Baja California. Metodología: se realizó un estudio clínico de corte transversal a pacientes pe...

  19. Pacientes pediátricos con VIH/sida en Baja California, México. Alteraciones bucales relacionadas

    OpenAIRE

    Domínguez Sánchez, Anitza; Universidad Autónoma de Baja California, Mexicali, México.; Verdugo Díaz, Roberto de Jesús; Verdugo Díaz; Gaitán Zepeda, Luis Alberto; Universidad Nacional Autónoma de México, México; Sánchez Rubio Carrillo, Ricardo Manuel; Universidad Autónoma de Baja California, Mexicali, México; Valles Medina, Ana María; Universidad Autónoma de Baja California, Tijuana, México

    2011-01-01

    Antecedentes: Baja California, México, ocupa el cuarto lugar nacional en casos reportados de VIH/sida. Por ser los pacientes pediátricos la población más vulnerable, el odontólogo debe diagnosticarlos y canalizarlos oportunamente para una adecuada atención. Objetivo: describir las alteraciones dentales y de mucosa oral asociadas más frecuentes en pacientes pediátricos con diagnóstico de VIH/sida en Baja California. Metodología: se realizó un estu¬dio clínico de corte transversal a pacientes p...

  20. Characterisation of an enamelled metallic object found in Guerrero Negro (Baja California) by PIXE and RBS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid (Spain); Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico); Centre Europeen d' Archeometrie - I.P.N.A.S., Universite de Liege, Allee du 6 Aout, 10 Bat-15, Sart Tilman, 4000-Liege 1 (Belgium)], E-mail: hcalvo@ulg.ac.be; Ruvalcaba, J.L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid (Spain); Salinas Nolasco, M.F. [Coordinacion de Conservacion del Patrimonio Cultural, Instituto Nacional de Antropologia e Historia (Mexico); Mejia, L.M. [Direccion de Arqueologia Subacuatica, Instituto Nacional de Antropologia e Historia (Mexico); Perdigon, K. [Coordinacion de Conservacion del Patrimonio Cultural, Instituto Nacional de Antropologia e Historia (Mexico)

    2008-05-15

    The coast of Guerrero Negro (Baja California) has been known for a long time by archaeologists for its shipwrecks. Archaeologists are recovering objects that come from sunken Spanish galleons in the colonial period, and reach the American coast in the frontier of the USA with Mexico. An enamelled metallic object was found next to the beach in Guerrero Negro. We have analysed the piece with proton induced X-ray emission (PIXE) and Rutherford backscattering (RBS) in an attempt to establish whether the object could come from one of the colonial shipwrecks and to valuate its cleaning process. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) have been also performed in three samples taken from the object in order to observe the heterogeneity of the material. The materials found revealed the presence of typical lead-glass enamels from with pigments such as cuprite (red), or lead-tin yellow used in colonial times. The metallic part consisted of brass. As for the cleaning process, the average efficiency considered as the weight% of chlorine removed, was of 83.4% for brass and 100% for ename0008.

  1. Northern Baja California Indian women's concepts of illness and healing: Implications for public health and clinical practitioners.

    Science.gov (United States)

    Longstreth, G F; Wilken-Robertson, M

    2010-01-01

    Lay health care workers (promotores) interviewed 313 female members of remote Indian groups in northern Baja California, Mexico regarding: (1) common childhood and adult illnesses and endorsement of 'traditional' and modern therapies; (2) illness causation beliefs and knowledge of biomedical principles; and (3) the relation of ethnic identity with concepts of effective biomedical and non-biomedical therapy. The most common illnesses/symptoms reported in adults were diabetes, hypertension, high cholesterol, cold/flu, diarrhoea, low/variable blood pressure and arthritis; and in children, cold/flu, diarrhoea, bronchitis, cough, fever, empacho and dehydration. Of 285 informants, more reported at least one childhood disorder than who reported at least one adult disorder was most helped by traditional therapy [83 (29.1%) versus 44 (15.4%); P<0.0001] and both therapies [81 (28.4%) versus 42 (14.7%); P<0.001]. They reported eight naturalistic and two personalistic illness causes and manifested variable biomedical knowledge. Indian or mixed Indian/Mexican ethnic self-identity predominated, and Indian identity was unrelated to endorsement of traditional therapy. The 'biocultural synthesis' is a useful theoretical framework for viewing the findings. The Indians' pluralistic concepts have important implications for public health care workers and biomedical practitioners.

  2. The physicochemical characterization of cave paintings of Baja California; Caracterizacion fisicoquimica de pigmentos y soportes en pinturas murales: caso Mayapan, Yucatan

    Energy Technology Data Exchange (ETDEWEB)

    Valdez, B.; Cobo, J.; Schorr, M. [Area de Corrosion y Materiales, Instituto de Ingenieria, Universidad Autonoma de Baja California, Blvd. Benito Juarez, S/N, 21280, Mexicali, B.C. (Mexico); Cota, L. [Centro de Ciencias de la Materia Condensada, UNAM, Ensenada, B.C. (Mexico); Oviedo, F. [Centro INAH - BC, Ensenada, B.C. (Mexico)]. e-mail: benval@iing.mxl.uabc.mx

    2006-07-01

    The Palaeolithic paintings of Baja California constitute an important contribution to the national, historic and cultural patrimony of Mexico. The aim of this investigation was to determine the physicochemical characteristics, the microstructure and texture of these polychrome paintings, painted on rocks encountered in the mountainous, desert/arid zones of Baja California and Baja California South. The first stage of this work was devoted to the examination and recording of the cave paintings of 'El Vallecito', a narrow fluvial valley displaying large granitic rocks emerging from the sandy soil. Tiny painting samples were collected and analyzed by SEM, EDS and FTIR techniques. The painters used four main colours: red, black, yellow and white. The paint raw materials are mineral pigments: white (kaolin, calcite, and gypsum), red (hematite), yellow (ochre, limonite), black (charcoal from burnt wood or calcined bones) and water as a diluent and/or a binder, all encountered in the painters habitat. The minerals were collected, ground and sometimes heated to change their tone. By mixing with water, a spreadable paste or a thick slurry was produced, which was applied with the fingers for lines or a piece of animal skin for figures, respectively. The 100% solids, dry paint converts into a dense, hard layer, incrusted into the grainy, rough, hollow granite rock surface. This paint might be called {sup s}tone on stone{sup ,} explaining its permanence for centuries enduring heat, wind and weather. A simulation of the painting technique was done at the Materials and Corrosion Laboratory, UABC by collecting mineral pigments, preparing the paint as a paste or slurry and applying it on a granitic rock. Knowing the paint composition, production and application techniques will be useful in e conservation and restoration of cave paintings and stone-built, ancient structures such as pyramids, cathedrals and monuments. (Author)

  3. Bioclimatología de la Coccidioidomicosis en Baja California, México

    Directory of Open Access Journals (Sweden)

    Raúl C. Baptista-Rosas

    2010-01-01

    Full Text Available El estudio bioclimático de la Coccidioidomicosis, enfermedad endémica de las zonas áridas de América ocasionada por ascomicetos del género Coccidioides spp., tiene una estrecha relación con dos aspectos: la distribución espacial de la enfermedad asociada a ambientes desérticos, y la correlación entre la incidencia de casos y eventos meteorológicos. A pesar de que el noroeste de México es un área endémica bien conocida, la situación actual de la enfermedad prácticamente está inexplorada. Por tal motivo, en este trabajo se regionalizó la probable área endémica en Baja California, por medio de un sistema de información geográfica (SIG utilizando variables bioclimáticas, y se analizó la relación entre eventos meteorológicos y los casos reportados de la enfermedad durante el periodo de enero de 1988 a diciembre de 1994. Se encontró correlación entre el número de casos reportados de la enfermedad, la precipitación pluvial mensual acumulada (PP y las temperaturas medias máxima y mínima. Existe evidencia a favor de que la región endémica propuesta para Baja California presenta un patrón de lluvias bimodal, en verano y en invierno, característico de zonas bioclimáticas transicionales. Los casos reportados de la enfermedad se registraron principalmente en los meses más secos del año después de las lluvias estacionales. Se concluye que Baja California reúne las condiciones bioclimáticas más favorables para el hábitat de Coccidioides spp. en la transición del bioma mediterráneo al desértico.

  4. Preliminary Analysis of Remote Triggered Seismicity in Northern Baja California Generated by the 2011, Tohoku-Oki, Japan Earthquake

    Science.gov (United States)

    Wong-Ortega, V.; Castro, R. R.; Gonzalez-Huizar, H.; Velasco, A. A.

    2013-05-01

    We analyze possible variations of seismicity in the northern Baja California due to the passage of seismic waves from the 2011, M9.0, Tohoku-Oki, Japan earthquake. The northwestern area of Baja California is characterized by a mountain range composed of crystalline rocks. These Peninsular Ranges of Baja California exhibits high microseismic activity and moderate size earthquakes. In the eastern region of Baja California shearing between the Pacific and the North American plates takes place and the Imperial and Cerro-Prieto faults generate most of the seismicity. The seismicity in these regions is monitored by the seismic network RESNOM operated by the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). This network consists of 13 three-component seismic stations. We use the seismic catalog of RESNOM to search for changes in local seismic rates occurred after the passing of surface waves generated by the Tohoku-Oki, Japan earthquake. When we compare one month of seismicity before and after the M9.0 earthquake, the preliminary analysis shows absence of triggered seismicity in the northern Peninsular Ranges and an increase of seismicity south of the Mexicali valley where the Imperial fault jumps southwest and the Cerro Prieto fault continues.

  5. Restricciones de liquidez en microempresas y la importancia del financiamiento informal en Baja California

    Directory of Open Access Journals (Sweden)

    Martín Ramírez-Urquidy

    2009-01-01

    Full Text Available La estructura industrial de México incorpora una proporción significativa de agentes que emprenden negocios a escalas reducidas y en un esquema de informalidad. Esta condición los aleja de los mercados formales de crédito, por lo que enfrentan una restricción permanente de liquidez. Este artículo prueba la hipótesis de que existen microempresas (MES no restringidas a pesar de esta limitación formal. Los resultados ilustran esta posibilidad al encontrar, en una muestra de mes del estado de Baja California, lo que implica el acceso a financiamiento externo y la importancia de las fuentes informales.

  6. Desarrollo, identidad cultural y turismo en los oasis de Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Alexandra Sauvage

    2013-01-01

    Full Text Available Este artículo ofrece un análisis de la integración de dos comunidades rurales, San Miguel y San José de Comondú, a los procesos de globalización económica que vive Baja California Sur, en el noroeste mexicano. Ese proceso permite advertir los riesgos de la patrimonialización y comodificación culturales de una ruralidad presionada por el crecimiento de los sectores de bienes raíces y turismo. Proponemos aquí que una avenida de conciliación es el establecimiento de una política cultural como eje principal de los proyectos de desarrollo de la entidad, que evite la mera comodificación de las tradiciones locales para el turismo, y reconozca el rol de los habitantes locales en la definición de los valores culturales locales.

  7. Evaluation of Governance in the Administration of Protected Areas on the Peninsula of Baja California

    Directory of Open Access Journals (Sweden)

    Naín MARTÍNEZ

    2016-01-01

    Full Text Available R ESUMEN En este artículo se analiza la incorporación de los principios normativos de la gobernanza en la gestión de las áreas naturales protegidas de la península de Baja California en el período 2007- 2011. A través de una revisión documental, se evaluaron la ef icacia, ef iciencia, participación, inclusión y equidad. Se encontró que la administración presenta cambios que tienden a mejorar su gobernanza. Sin embargo, éstos aún son insuf icientes para incorporar a los actores sociales, por lo que es necesario continuar mejorando las prácticas gubernamentales y af inar los mecanismos de participación.

  8. Port competitiveness in the Mexican Pacific Ocean, with special reference to >Ensenada, Baja California

    Directory of Open Access Journals (Sweden)

    Carlos Israel Vázquez León

    2014-11-01

    Full Text Available This work aims, identify and compare the determinants of port competitiveness of the three major ports on the Mexican Pacific coast: Lázaro Cárdenas in Michoacán; Ensenada in Baja California; and Manzanillo in Colima. Such comparison was performed using the Analytic Hierarchy Process along with the model of Strengths, Weaknesses, Opportunities and Threats. Notable differences were found among these ports, both in terms of the infrastructure for competitiveness, as well as their business strategies.The competitive positioning observed from this analysis, shows that the Port of Ensenada is located at a significant disadvantage, which compromises their potential to exploit opportunities offered by Pacific Rim and the East–West Maritime Corridor of the Northern Hemisphere.

  9. New constraints on deglacial marine radiocarbon anomalies from a depth transect near Baja California

    Science.gov (United States)

    Lindsay, Colin M.; Lehman, Scott J.; Marchitto, Thomas M.; Carriquiry, José D.; Ortiz, Joseph D.

    2016-08-01

    Previous studies have shown that radiocarbon activities (Δ14C) in the low-latitude, middepth Pacific and Indian Oceans were anomalously low during Heinrich Stadial 1 (HS1, ~17.8-14.6 ka) and the Younger Dryas (YD, ~12.8-11.5 ka), coincident with intervals of rising atmospheric CO2 concentration and declining atmospheric Δ14C. However, a full explanation of these events remains elusive due to sparse and sometimes conflicting data. Here we present new 14C measurements on benthic and planktic foraminifera that, in combination with previously published measurements, enable us to reconstruct the Δ14C depth gradient near Baja California. Vertical profiles were similar to present during the Last Glacial Maximum and Bølling/Allerod (14.6-12.8 ka) but display a pronounced middepth (~700 m) Δ14C minimum during HS1 and the YD. The latter observation, along with a comparison to other regional reconstructions, appears to rule out intermediate waters from the north or from directly below as proximate sources of aged 14C-depleted ocean carbon during deglaciation and point instead to changes in the composition of Equatorial Pacific intermediate waters. Simple mixing constraints require Equatorial Pacific intermediate waters to be only slightly lower in Δ14C than at Baja California, in contrast with previous observations of extremely low Δ14C at Galapagos Rise. While the latter may have been influenced by localized releases of geologic (14C-dead) CO2, the smaller and more widespread deglacial Δ14C anomalies in the Arabian Sea and North Pacific seem to require a source of aged carbon in the glacial deep Southern and Pacific Oceans for which there is growing evidence.

  10. Spatial influence and oceanic thermal response to Santa Ana events along the Baja California peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Castro, R. [Facultad de Ciencias Marinas, Universidad Autonoma de Baja California, Ensenada, Baja California (Mexico)]. E-mail: rubenc@uabc.mx; Mascarenhas, A.; Martinez-Diaz-de-leon, A. [Instituto de Investigaciones Oceanologicas, Universidad Autonoma de Baja California, Ensenada, Baja California (Mexico); Durazo, R. [Facultad de Ciencias Marinas, Universidad Autonoma de Baja California, Ensenada, Baja California, (Mexico); Gil Silva, E. [Instituto de Investigaciones Oceanologicas, Universidad Autonoma de Baja California, Ensenada, Baja California, (Mexico)

    2006-07-15

    Meteorological data were recorded at eight stations located along the coast of the Pacific Ocean and three along the coast of the Gulf of California, aimed to assess the spatial influence of Santa Ana weather conditions in the Baja California peninsula. February 2002 featured two Santa Ana events: one from the 9 to the 12 and another from the 21 to the 22. The first Santa Ana event had the strongest winds, however relative humidity and temperature behaved similarly on both events at some stations. Data from the Pacific Ocean showed typical Santa Ana condition patterns: wind speed and temperature increase opposed to decreased relative humidity values. Data from the Gulf of California did not show the typical temperature rise of a Santa Ana condition, but there was a decrease on the amplitude of the diurnal variability of air temperature and relative humidity as well as a marked increase on wind strength. Wind direction during the Santa Ana events on the Pacific side was NE and NW on the Gulf of California. NE winds are associated to the shift on the position of the North Pacific High Pressure Center, which moves towards the continent. Data suggest that relative humidity may be the best parameter to monitor both occurrence and length of Santa Ana conditions on the Pacific side. Normal weather conditions show a negative air-sea temperature difference, but during both Santa Ana events this difference was positive and higher than 10 degrees Celsius. Latent and sensible heat fluxes drastically increased during both events, reaching values more than three times higher than those for normal conditions, which is due to the presence of strong winds combined with a drier and hotter air mass over the ocean. [Spanish] Con el proposito de estudiar la influencia espacial de condiciones Santa Ana a lo largo de la peninsula de Baja California, se registraron datos meteorologicos en ocho estaciones localizadas en el lado del Pacifico y tres estaciones en el Golfo de California. En

  11. Overview Of Cal-Mex 2010: US-Mexico Collaborative Project On Air Quality And Climate Change In The California-Mexico Border Region

    Science.gov (United States)

    Molina, L. T.; Cal-Mex Science Team

    2010-12-01

    The composition of the atmosphere over the US-Mexico border region is affected by cross-border transport of emissions in both directions. Air quality issues in the California-Mexico (Cal-Mex) border are associated with air masses originating in the portion of the border region adjacent to California, which includes two of the sister city pairs (Tijuana-San Diego and Mexicali-Calexico) that have the most severe air pollution problems, posing a serious health threat to their inhabitants as well as affecting ecosystem viability and regional climate for large downwind distances. During May-June 2010, an intensive field study was undertaken by US-Mexico collaborative teams to characterize the major sources of primary and secondary particulate matter and precursor gases in the California-Mexico (Cal-Mex) border region, their transport and transformation, and the impact of these emissions on regional air quality and climate. The ground-based measurements included a central fixed site located in Tijuana that housed state-of-the-science instruments to measure gases, aerosols, radiation and meteorological parameters; a mobile eddy covariance laboratory that measured surface-atmosphere exchange fluxes of carbon dioxide, nitrogen oxides, and particle number; several mobile units for criteria pollutants and meteorological parameters; and measurements of fine particles and trace gases at the border crossing areas. Preliminary results from the field study will be presented. Cal-Mex Science Team includes: Molina Center for Energy and the Environment, Texas A & M University, Scripps Institution of Oceanography/University of California at San Diego, Virginia Tech, San Diego State University, National University of Mexico, National Institute of Ecology/Mexican Ministry of the Environment, University of the State of Morelos, LT Consulting Group, University of Baja California (Mexicali, Tijuana, Ensenada, Valle de Las Palmas campuses), Secretary of the Environment of Baja California

  12. The Baja California Borderland and the Neogene Evolution of the Pacific-North American Plate Boundary

    Science.gov (United States)

    Fletcher, J. M.; Eakins, B. W.

    2001-12-01

    New observational data on Neogene faulting in the borderland of Baja California places important constraints on tectonic models for the evolution of the Pacific-North American (P-NA) plate boundary and rifting in the Gulf of California. Neogene faults in the borderland range from strike slip to normal slip and accommodate integrated transtension. Most have east-facing escarpments and likely reactivate the former east-dipping accretionary complex. Numerous lines of evidence indicate that Neogene faults are still active and accomplish a significant component ( ~1-5 mm/yr) of Pacific-North American shearing. Quaternary volcanoes are found offshore and along the Pacific coastal margin, Quaternary marine terraces are warped and uplifted as high as 200 masl. Many of the offshore faults have fresh escarpments and cut Holocene sediments. Extensive arrays of Quaternary fault scarps are found throughout the coastal region and in Bahia Magdalena they are clearly associated with major faults that bound recently uplifted islands. A prominent band of seismicity follows the coast and eight earthquakes (Ms>5.0) were teleseismically recorded between 1973 and 1998. This evidence for active shearing indicates that the Baja microplate has not yet been completely transferred to the Pacific plate. The best lithologic correlation that can be used to define the total Neogene slip across the borderland faults is the offset between the Magdalena submarine fan and its Baja source terrane. The distal facies of the fan drilled during DSDP leg 63 is dominated by mudstone and siltstone that contain reworked Paleogene cocoliths derived from strata correlative with the Tepetate formation found throughout the borderland and fine-grained sandstone derived from a source terrane of granitoid basement. The Middle Miocene La Calera formation of the Cabo trough is one of many granitoid-clast syn-rift alluvial deposits that could form the continental counterpart of the submarine fan near the mouth of the

  13. Especialización industrial y desarrollo empresarial en Baja California

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray

    2003-01-01

    Full Text Available La especialización industrial en Baja California en el sector de productos metálicos, maquina ria y equipo, s e asocia en economías de redes por interacciones de costos entre las grandes empresas asiáticas y del sur de California que conviven en la región conforme a las nuevas reglas del TLCAN y el fuerte peso de la subcontratación y las operaciones intraindustriales. En este contexto, se evalúa el impacto sobre la vida económica y social de las empresas para comprobar si la perspectiva de bienestar social a través del empleo, resultado de la estrategia industrial de atraer inversión extranjera directa, tiene que ver más con la discriminación salarial que con la productividad, y si los incrementos salariales están influidos por alzas en productividad y la especialización. Se parte de que el bienestar es clave en la estrategia de política industrial regional con objetivos competitivos para el desarrollo regional y empresarial, donde este último se inhibe ante la limitada estrategia estatal .

  14. Influence of anomalous subarctic water intrusion on phytoplankton production off Baja California

    Science.gov (United States)

    Espinosa-Carreón, T. L.; Gaxiola-Castro, G.; Durazo, R.; De la Cruz-Orozco, M. E.; Norzagaray-Campos, M.; Solana-Arellano, E.

    2015-01-01

    The southern region of the California Current (CC) off Baja California represents a transitional environment, with the influence of low temperature and less saline CC water during spring and summer, and warm and salty tropical and subtropical conditions through the end of summer and autumn. From 2002 to 2006, an anomalous subarctic water (SAW) intrusion generated changes in the epipelagic ecosystem dynamics, affecting phytoplankton biomass and primary production. The goal of the present work is to show the effects of the SAW intrusion off Baja California in the phytoplankton production during the two contrasting years 2002 and 2005. Our results show that the minimum water salinity was associated with density levels of 24.6-25.5 kg m-3 in 2002 and 24.3-25.2 kg m-3 in 2005, indicating that the anomalous SAW intrusion was more pronounced in 2005. In 2005, the mean chlorophyll concentration was low (1.0 mg m-3 in some months. CHL values were significantly different between the north and south zone and among months (p<0.01). The mean values of the photosynthetic parameters (maximum light utilization coefficient (αB) and maximum photosynthesis rate (PBm)) were one order of magnitude higher in 2005 compared to 2002 (p<0.01). The primary production estimated by the Herman and Platt model and the Carr model was very different in 2002 (mean values of 907 and 143 mgC m-2 d-1 respectively), but similar in 2005 (750 and 1006 mgC m-2 d-1 respectively). The differences between models may be due to the diverse chlorophyll data used in the singular models (in situ vs. satellite-derived), and to the weight of the phytoplankton photosynthetic parameters in each algorithm. We conclude that for the present data set the Herman and Platt model is more suitable. To assess the relative importance of physical variables, as well as bio-optical and physiological parameters in primary production, we conducted a principal component analysis (PCA). There was an apparent separation between the

  15. Food webs including parasites, biomass, body sizes, and life stages for three California/Baja California estuaries

    Science.gov (United States)

    Hechinger, Ryan F.; Lafferty, Kevin D.; McLaughlin, John P.; Fredensborg, Brian L.; Huspeni, Todd C.; Lorda, Julio; Sandhu, Parwant K.; Shaw, Jenny C.; Torchin, Mark E.; Whitney, Kathleen L.; Kuris, Armand M.

    2001-01-01

    This data set presents food webs for three North American Pacific coast estuaries and a “Metaweb” composed of the species/stages compiled from all three estuaries. The webs have four noteworthy attributes: (1) parasites (infectious agents), (2) body-size information, (3) biomass information, and (4) ontogenetic stages of many animals with complex life cycles. The estuaries are Carpinteria Salt Marsh, California (CSM); Estero de Punta Banda, Baja California (EPB); and Bahía Falsa in Bahía San Quintín, Baja California (BSQ). Most data on species assemblages and parasitism were gathered via consistent sampling that acquired body size and biomass information for plants and animals larger than ∼1 mm, and for many infectious agents (mostly metazoan parasites, but also some microbes). We augmented this with information from additional published sources and by sampling unrepresented groups (e.g., plankton). We estimated free-living consumer–resource links primarily by extending a previously published version of the CSM web (which the current CSM web supplants) and determined most parasite consumer–resource links from direct observation. We recognize 21 possible link types including four general interactions: predators consuming prey, parasites consuming hosts, predators consuming parasites, and parasites consuming parasites. While generally resolved to the species level, we report stage-specific nodes for many animals with complex life cycles. We include additional biological information for each node, such as taxonomy, lifestyle (free-living, infectious, commensal, mutualist), mobility, and residency. The Metaweb includes 500 nodes, 314 species, and 11 270 links projected to be present given appropriate species' co-occurrences. Of these, 9247 links were present in one or more of the estuarine webs. The remaining 2023 links were not present in the estuaries but are included here because they may occur in other places or times. Initial analyses have examined

  16. Isolation by distance among California sea lion populations in Mexico: redefining management stocks.

    Science.gov (United States)

    González-Suárez, M; Flatz, R; Aurioles-Gamboa, D; Hedrick, P W; Gerber, L R

    2009-03-01

    Understanding the spatial structure of a population is critical for effective assessment and management. However, direct observation of spatial dynamics is generally difficult, particularly for marine mammals. California sea lions (Zalophus californianus) are polygynous pinnipeds distributed along the Pacific coast of North America. The species' range has been subdivided into three management stocks based on differences in mitochondrial DNA, but to date no studies have considered nuclear genetic variation, and thus we lack a comprehensive understanding of gene flow patterns among sea lion colonies. In light of recent population declines in the Gulf of California, Mexico, it is important to understand spatial structure to determine if declining sea lion colonies are genetically isolated from others. To define population subdivision and identify sex biases in gene flow, we analysed a 355-bp sequence of the mitochondrial DNA control region and 10 polymorphic microsatellite loci from 355 tissue samples collected from six colonies distributed along Mexican waters. Using a novel approach to estimate sex biases in gene flow, we found that male sea lions disperse on average 6.75 times more frequently than females. Analyses of population subdivision strongly suggest a pattern of isolation by distance among colonies and challenge current stock definitions. Based on these results, we propose an alternative classification that identifies three Mexican management units: Upper Gulf of California, Southern Baja Peninsula, and Upper Pacific Coast of Baja. This revised classification should be considered in future assessment and management of California sea lion populations in Mexican waters.

  17. Geological Evidence That Resolves the Baja-BC Controversy: Detrital Zircons Indicate That Vancouver Island Was Adjacent to Southern California in the Late Cretaceous

    Science.gov (United States)

    Guest, B.; Matthews, W.; Coutts, D. S.; Bain, H.; Hubbard, S. M.

    2015-12-01

    The Baja-BC hypothesis is at the center of a great earth sciences controversy. It stems from paleomagnetic observations that require large-scale displacements of continental crust from low latitudes (Baja, California) to moderate latitudes (British Columbia). Many geologists dispute the scale of the displacements due to a lack of corroborating geological evidence. We provide a robust, geological dataset that confirms the paleomagnetic observations. Detrital zircons from Cretaceous to Paleocene sandstone of the Nanaimo Group, which crops out in western Vancouver Island and the Gulf Islands of southwest British Columbia, are analyzed. The data show a clear transition from local 300 Ma grains in the Maastrichtian-Paleogene. An identical pattern is observed in detrital zircon datasets from southern California forearc basin deposits, and schists interpreted as the subducted remnants of forearc deposits. With a high-n dataset (n=3041) we are able to rule out possible >300 Ma source regions in Canada and the northern United States, and uniquely tie Nanaimo Group rocks to the Mojave-Sonora region of SW United States. This implies that at the end of the Cretaceous, Vancouver Island and western mainland BC were adjacent to southern California and northwestern Mexico, requiring 1900 km of displacement during the latest Cretaceous and Paleocene, consistent with paleomagnetic results. An implication of this result is that the western Coast Batholith of southwest BC was positioned between the northern Peninsular Ranges and southern Sierra Nevada batholiths in the late Cretaceous, and likely represents a displaced segment of a once continuous Cordilleran arc batholith. These results have broad implications for our understanding of episodic arc magmatism in the Cordillera, the tectonic evolution of western North America, Laramide orogenesis, the development and extent of the Nevadaplano, and the onset of Basin and Range extension.

  18. Migración por empleo en México. La experiencia de Baja California entre 2008 y 2012

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray Lagarda

    2014-01-01

    Full Text Available Para entender el reto del empleo que enfrenta México, en un contexto de diversidad regional, se ofrece una expli - cación a la paradoja actual de crecimiento del empleo y de la tasa de desempleo que ocurre al mismo tiempo en Baja California. Mediante la estimación de un modelo de datos de panel, se genera evidencia de que los flujos migratorios del interior del país son mayores que el aumento de la po - blación ocupada, debido a que tanto ésta como los salarios y el nivel de competitividad social de Baja California in - fluyen de manera directa en las decisiones de las personas para moverse a dicha entidad.

  19. Dinámica de los componentes demográficos en Baja California, durante el periodo 1985-1990

    Directory of Open Access Journals (Sweden)

    Gabriel Estrella Valenzuela

    1991-09-01

    Full Text Available En este trabajo se identifican los rangos predominantes en la dinámica de los componentes demográficos del estado de Baja California y sus municipios, durante el período 1985-1990. Para ello, se utilizan y combinan datos de estadísticas vitales, censales y de las Encuestas Demográficas de Baja California de 1986 y 1990. A partir del análisis de la mortalidad y la fecundidad, se logra determinar una tendencia de estabilidad en el componente natural de la dinámica demográfica del estado, con variaciones marginales a nivel municipal. En el rubro de crecimiento social, sin embargo, se observa un notable y claro incremento en la movilidad de la población que se sustenta en dos componentes: un incremento en la tasa de emigración desde el estado en su conjunto y una más elevada y consistente tendencia al incremento en las tasas de inmigración hacia Baja California, que revierte la tendencia decreciente del peso del crecimiento social en la entidad

  20. Demografía y economía de una capital estatal. Mexicali, Baja California

    Directory of Open Access Journals (Sweden)

    Gabriel Estrella Valenzuela

    1996-01-01

    Full Text Available This work has as a main objective, to identify, in a general way, the sectors of the economical activity in which the city of Mexicali presents a grade of specialization in respect to the state of Baja California in general. To accomplish such objective, in the first part, the general characteri'stics that have definedthe tendencies of demographic behavior in this zone of the country through the 20th century are marked, with the purpose of making evident the nexus that has existed between the modalities that have assumed the economical development of Mexicali, and the fluctuations that have been observed in the components of its population dynamic. The second part of this work is about the evaluation of the specialization of the economical structure of Mexicali, related to the capacity of creating jobs, and the kind of jobs that are created. In this case, tha analitic perspective ofthe "economical basis" is used, since it's important to show the role the border with the United States has played, in relation to the possibilities -past and present- of development in the economy of this area through the capacity of responding to the external demand of goods and services.

  1. Antecedentes históricos de los indígenas de Baja California

    Directory of Open Access Journals (Sweden)

    Julia Bendímez Patterson

    1987-09-01

    Full Text Available Este estudio explica la forma como se han ido desenvolviendo los primeros pobladores de esta región, inicia en el periodo paleo-indígena, para después avanzar paulatinamente en el tiempo hasta llegar al problema actual que caracteriza a muchas de las comunidades indígenas de nuestro país. No obstante que la historia ha sido documentada por la sociedad dominante, sin contar con la versión de los actores nativos, y en lo que se refiere a estas sociedades, ésta es sumamente escueta. En la actualidad, la conciencia de muchos mexicanos no-indígenas está permeada con la concepción heredada desde la época colonial y continuamos marginándolos y considerándolos como un obstáculo para la modernización, al grado que, actualmente quedan menos de 1,000 indígenas en las comunidades de Baja California.

  2. Pesquerías ribereñas en Baja California

    Directory of Open Access Journals (Sweden)

    Ana María Avilés Muñoz

    1987-01-01

    Full Text Available El presente artículo tiene como objetivo establecer los resultados de la investigación sobre las formas de organización y producción de las pesquerías en Baja California, su grado de desarrollo y la participación del Estado en relación con el proceso de consolidación, desarrollo, requerimientos específicos de las pesquerías y estímulos para la generación de productos pesqueros de bajo valor comercial o de consumo mayoritario. Este trabajo se sirvió de dos tipos de investigación: la documental y la de campo. La investigación documental se utilizó para seleccionar elementos teóricos, conocer las políticas y acciones del Estado en cuanto a pesca, obtener estadísticas y recabar información. La investigación de campo fue el medio para lograr acercamientos al universo de estudios. Se puede concluir que tomando en cuenta la particularidad de la actividad pesquera, en tanto ésta depende en mayor medida que otras actividades productivas a las condiciones climáticas y a los ciclos de abundancia y escasez de especies, que la actividad requiere ser intensiva en las temporadas propicias.

  3. en un área natural protegida en Baja California Sur

    Directory of Open Access Journals (Sweden)

    Elizabeth Olmos-Martínez

    2008-01-01

    Full Text Available Aquí se aborda el concepto de pobreza, enmarcado en el contexto de un área natural protegida (ANP, con la metodología propuesta por la Secretaría de Desarrollo Social (SEDESOL, cuya política pública maneja tres categorías para medirla: pobreza alimentaria, pobreza de capacidades y pobreza de patrimonio. El estudio de caso se efectuó en el ejido San Jorge (ESJ, ubicado dentro de la Reserva de la Biosfera Sierra La Laguna (REBISLA, en Baja California Sur. El análisis está basado en datos recolectados en entrevistas a los pobladores del lugar; se consideró el ingreso real diario per cápita, el cual indica si la persona es capaz de satisfacer las necesidades comprendidas en cada categoría, con un ingreso mínimo indispensable. Los resultados indican que la pobreza en la zona, de 2000 a 2004, no varió significativamente. Se concluyó que los habitantes del ESJ son pobres, según los propios parámetros de SEDESOL, y que su condición no ha mejorado, aunque viven en un ANP. Se analizan algunas alternativas que podrían ayudar a amortiguar este rezago.

  4. Evaluación del aprendizaje de las microempresas de Baja California

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    Michelle Texis Flores

    2015-01-01

    Full Text Available En este trabajo se evalúa el desempeño de 1 183 microempresas, que recibieron servicios de desarrollo empresarial en Baja California, mediante un modelo que utiliza las ventas acumuladas como variable proxy de experiencia, para calcular los coeficientes de elasticidad de aprendizaje por empresa. Se supone que a través de prácticas de asistencia, capacitación y acompañamiento mejora la situación de la microempresa, respecto al uso de los recursos. En consecuencia, el modelo es un instrumento de evaluación que permite determinar si las microempresas desarrollan procesos de aprendizaje durante el periodo en el que reciben apoyo. Se encontró que las que mostraron alguna mejora requieren de nuevos estímulos para incrementar su tasa de aprendizaje. Por otra parte, las que no aprenden representan áreas de oportunidad para el diseño e implementación de servicios de desarrollo empresarial.

  5. Mobile colposcopy in urban and underserved suburban areas in Baja California

    Science.gov (United States)

    Madiedo, Marta; Contreras, Sonia; Villalobos, Octavio; Kahn, Bruce S.; Safir, Amit; Levitz, David

    2016-03-01

    Cervical cancer is the leading cause of cancer death for women in low resource settings, often affecting the most economically disenfranchised segment of the population. The key challenge with cervical cancer is the lack of an effective screening program for many of the at-risk, difficult-to-reach women. Outreach programs that utilize mobile clinics to increase access to screening and care in Baja California have been developed. However, many barriers such as quality assurance, efficient referral remained a challenge in this region. Visualization-based co-tests together with cytology (Pap smears) as a primary screen have been proposed. Here, the mobile colposcope of the enhanced visual assessment (EVA) is used to capture an image immediately following a Pap smear. EVA images were reviewed by expert colposcopists. Initial or preliminary data from pilot services showed that Pap false positives and Pap false negatives maybe reduced by expert review of EVA images. This suggests that reviewing of EVA images may be instrumental in catching inaccurate Pap results, thereby improving care. Thus, there is a need to further explore the benefits of using EVA as additional information when conducting Pap smear screenings.

  6. Estimated Impact of Contextual Variables on Academic Achievement among Students in Baja California

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    Mauricio Carvallo Pontón

    2007-11-01

    Full Text Available In the following article, the effects of diverse variables are analyzed contextually in the educational achievement on a sample of 1,817 students of the sixth grade of elementary school and 1,239 of third year of high school of Baja California, who responded to the National Tests offered by the National Institute for the Evaluation of the Education in 2004. The results observed are consistent with the reported in most of the national and international literature: the women present better performance than the men in reading comprehension, and the men register better performance in math; the students with ages over the ones that correspond to the sixth grade of elementary school or third year of secondary school, present lower performance levels to those of their schoolmates; the students of the morning shift present higher performance levels compared to the evening shift students; and the students of private schools present better results than those of public schools. It was also analyzed, through hierarchical lineal models, the effect of the socioeconomic level of the context of the school and of the professor in the educational achievement. In all the cases, the levels of variance explained turned out to be smaller that the registered in other similar national studies.

  7. El kusiyai: chamanismo entre las poblaciones yumanas del norte de Baja California

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    Michael Winkelman

    2006-01-01

    Full Text Available Las prácticas curativas de los grupos yumanoparlantes del norte de Baja California estuvieron bajo el liderazgo del kusiyai, una figura desvanecida en los modernos estudios etnográficos, pero cuyas actividades pueden ser reconstruidas a partir de los reportes de etnógrafos, geógrafos y exploradores de principios del siglo veinte. Es posible observar en esas actividades ciertos patrones similares a los que siguen las prácticas curativas del chamanismo. Más aún, esas actividades pueden ser reconstruidas en más detalle si utilizamos el paradigma chamánico para organizar los diversos tipos de material relacionado. Cabe señalar, por otra parte, que esta perspectiva ofrece en lo particular la expectativa de un posible resurgimiento futuro de esta tradición cultural. La perspectiva moderna sobre los universales del chamanismo y sobre los aspectos innatos de las actividades chamánicas es congruente con las creencias tradicionales de que los chamanes eran autodidactas en el desarrollo de sus relaciones con los poderes y lugares espirituales.

  8. Diversificación institucional y educación superior en Baja California en 2000

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    Patricia Moctezuma Hernández

    2005-01-01

    Full Text Available Este artículo aborda la diversificación del Sistema Estatal de Educación Superior (sees de Baja California, según la especialización económica regional existente y el proceso histórico de su conformación. El estudio concluye que la percepción de los usuarios sobre la educación superior es obra más bien de los esfuerzos individuales de las instituciones, que de la coordinación estatal, debido a que la opinión de los distintos actores sobre la definición de la política gubernamental es limitada. Para llegar a esta conclusión, se efectuó una evaluación del sees mediante una encuesta a estudiantes, y entrevistas a rectores y directores de las diferentes instituciones de educación superior (ies, de la entidad, durante el primer trimestre de 2000. Los criterios utilizados fueron la equidad y calidad.

  9. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in November 2007

    Science.gov (United States)

    2008-07-01

    Durazo Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn University of California Santa Barbara, CA Paul Choboter...CalPoly State University San Luis Obispo, CA Roger Hewitt NOAA La Jolla, CA Carmen G. Castro Consejo Superior de Investigaciones

  10. Turismo y Sustentabilidad en Pequeñas Localidades Localidades Costeras de Baja California Sur (BCS

    Directory of Open Access Journals (Sweden)

    Reyna Ibañez Pérez

    2014-01-01

    Full Text Available El fomento del turismo se realiza en sitios que, aunque pequeños, cuentan con atractivos naturales y culturales, tal es el caso de las zonas costeras. Tan solo en México, se estima que existen más de 1,100 comunidades que dependen directamente de dicha actividad, esta te ndencia se refleja, de igual manera, en pequeñas localidades costeras de Baja California Sur (BCS. En este sentido, el objetivo de este trabajo fue realizar un an álisis exploratorio que permitió detectar a las comunidades costeras de BCS, donde el turismo genera un aporte importante a su economía local, además , se buscó identificar la problemática general que éstas enfrentan. Para realizar dicho estudio se revisó literatura, se organizó información estadística y se elaboró un análisis Fortalezas, Oportunidades, Debilidades y Amenazas (FODA. Los resultad os apuntan a que, en BCS, existen más de 35 localidades ru rales vinculadas con dicha actividad que comparten como problemática la escasa in fraestructura y la carencia de medidas de control de la afluencia turística. La principal recomendación es desarrollar líneas de investigación que permitan aportar elementos para medir la sustentabilidad turística a nivel local y, co n base en ello, diseñar medidas para la adecuada conducción de tan importante actividad.

  11. Stratigraphy of Pyroclastic Deposits of EL Aguajito Caldera, Baja California Sur, MÉXICO

    Science.gov (United States)

    Osorio Ocampo, L. S.; Macias, J. L.; García Sánchez, L.; Pola, A.; Saucedo, R.; Sánchez, J. M.; Avellán, D. R.; Cardona, S.; Reyes-Agustín, G.; Arce, J. L.

    2015-12-01

    El Aguajito caldera is located in the State of Baja California Sur, it comprises an area of 450 km2 and sits within the Santa Rosalía Basin which is controlled by NE-SW extensional structures and the NW-SE Cimarron Fault that transects the caldera structure. The oldest rocks are ~90 Ma granodiorites covered by an Oligocene-Miocene volcano-sedimentary sequence, the Miocene Santa Lucia Formation and La Esperanza basalt. Pliocene volcanism is represented by La Reforma caldera, El Aguajito caldera, and the Tres Vírgenes Volcanic complex. This study focuses on the cartography and stratigraphy of area in order to understand the evolution of the volcanic system. The stratigraphy from base to top consists of a series of shallow marine sediments (fossiliferous sandstones) covered by a thick sequence of ignimbrites and pyroclastic flows interbedded with volcaniclastic deposits (Gloria and El Infierno Formations). On top of these deposits is El Aguajito caldera, it consists of a 2 m thick pumice fallout followed by an ignimbrite with three transitional lithofacies: a ≤30-m thick light-pink pyroclastic flow enriched in pumice at the base that gradually becomes enrich in lithics towards the top with the occurrence of degasing pipes. On top rests a 15 m-thick light-purple ignimbrite slightly welded with fiammes and a sequence of pumiceous pyroclastic flows and fallouts. These deposits have been associate to the caldera formation with a collapse diameter of ~8 km marked by rhyolitic domes exposed along a ring collapse crowned the sequence as well as NW-SE aligned rhyolitic domes parallel to the seashore. This cartography allowed to present a preliminary new geological map with four stratigraphic units recognized so far, that were emplaced under subaerial conditions beginning with a Plinian column followed by the emplacement of El Aguajito ignimbrite with its subsequent caldera collapse and finally the extrusion of resurgent domes.

  12. Local Seismological Networks in Northern Baja California: Some Interpretation of Results.

    Science.gov (United States)

    Frez, J.; Acosta, J.; Nava, F.; Gonzalez, J.; Alvarez, M.

    2002-12-01

    Since 1997, we have installed local seismological networks in northern Baja California (Reftek stations, three digital components, one to four months operation, covering areas of about 50 km x 50 km) for detailed microseismicity surveys of several fault systems in the region: Cerro Prieto, San Miguel, Agua Blanca, Sierra Juarez, and areas in between. Immediate results are location of about 1500 hypocenters, determination of about 400 focal mechanisms, and some structural information on the crust. In this presentation, we focus on: a) a summary of the spatial distribution of the hypocenters, focal mechanisms, and P and T axes; b) the role of the Ojos Negros Valley in the regional seismotectonics, and c) the existence of orthogonal alignments of epicenters not necessarily associated with mapped fault traces. Most of the activity is not clearly associated with fault traces: the exception is the SE segment of the San Miguel fault, the same one where destructive earthquakes occurred in 1954 and 1956. Most of the activity appears to be correlated with valleys (Ojos Negros, Trinidad-San Matias), or to simply occur between fault traces, or to belong to epicenter alignments of ~15 km or more in length which are part of longer segments that are apparent in regional seismicity maps (SCSN and RESNOM catalogs). This regional and local alignments show an orthogonal pattern. In a simple interpretation, they could represent a very new fracture proccess in a still mostly homogeneous material, not yet expressed as fault ruptures. All P and T axes azimuthal distributions from the various areas of study show a well defined global maximum consistent with the direction of regional stresses (about NS and EW, for P and T axes, respectively). However, the P axes are distributed on the focal sphere as an almost NS strip, particularly for the Ojos Negros Valley, indicating an extensional regime.

  13. La Baja California inventada: visiones sobre un territorio mexicano a mediados del siglo XX

    Directory of Open Access Journals (Sweden)

    Héctor Mendoza Vargas

    2015-01-01

    Full Text Available Resumen. Este artículo examina los viajes de Peter Gerhard y Ángel Bassols Batalla por la Baja California en los años cincuenta. Ante sus ojos emerge un espacio inventado a partir de la experiencia de cada uno en la península. Gerhard, como viajero, integraba una imagen práctica, placentera y lúdica dirigida a los turistas estadounidenses que con la rapidez y la seguridad del automóvil, podrían disfrutar del sol, las playas, los ranchos y la aventura del pasado histórico en los sitios misionales, además de la caza y la pesca deportiva. Por su parte, Bassols Batalla se adentró al territorio como explorador y, a través de una planeación racional de sus travesías y del análisis geoeconómico como metodología, concluyó que era necesario favorecer la colonización, la consolidación del Estado, el interés nacional y la reafirmación de la soberanía. La comparación entre las visiones de ambos autores señala coincidencias y diferencias que ayudan a comprender la relevancia del viaje geográfico como fuente de información y método de trabajo, indispensable para entender la realidad de una región aislada de México.

  14. Riesgo de contaminación del acuífero arroyo Alamar en Tijuana, Baja California

    OpenAIRE

    Marnie González Estévez; Vicente Sánchez Munguía

    2013-01-01

    El acuífero del arroyo Alamar, en Tijuana, Baja California, es uno de los escasos suministros de agua con que cuenta esta ciudad. En el área que recorre el Alamar se realizan actividades que, aunadas a la falta de medidas de control y vigilancia, inciden en la contaminación del lugar. De acuerdo con las fuentes contaminantes examinadas en el presente estudio, aquí se presentan resultados de un ejercicio de evaluación del riesgo de contaminación al que está expuesto el acuífero, mediante la in...

  15. Prospectiva del Programa de Ahorro Sistemático Integral en Mexicali, Baja California, México

    OpenAIRE

    José A. Suástegui Macías; Carlos Pérez Tello; H. Enrique Campbell; Hernán D. Magaña Almaguer

    2013-01-01

    El propósito de este trabajo es brindar información actualizada que permita elaborar una prospectiva del programa impulsado por el gobierno federal mexicano bajo el nombre de Programa de Ahorro Sistemático Integral (ASI) para el ahorro y uso eficiente de energía en el sector vivienda de Mexicali, Baja California. El presente estudio se realiza utilizando datos históricos del programa desde 1990 a la fecha e históricos de consumo de usuarios del servicio eléctrico. Se analiza la evolución del ...

  16. La Participación Ciudadana y el Enfoque Micro Social de la Seguridad Pública: El Caso de Baja California

    OpenAIRE

    2003-01-01

    La inseguridad pública en Baja California aumenta, como en el resto de la República Mexicana, a raíz del error de diciembre de 1994. Sin embargo, la problemática en el Estado fue atendida estructuralmente hasta 1998, a través de la participación decidida de la sociedad, principalmente del sector empresarial. Un elemento fundamental en el ataque frontal a la delincuencia ha sido la conformación del Consejo Ciudadano de Seguridad Pública (CCSP), ya que sus acciones y recomendaciones han permit...

  17. The role of human capital and learning in Mexican microenterprises: The experience of the state of Baja California

    Directory of Open Access Journals (Sweden)

    Martín Ramírez Urquidi

    2014-01-01

    Full Text Available This work aims at understanding the structure of human capital and learning in low value added microenterprises of Baja California and to determine the role of such factors in microenterprise performance, in order to establish a diagnosis on their contribution and get some public policy implications for the sector. The results confirm the importance of human capital on the performance of these businesses, since there is a relationship between human capital and performance as measured in different ways. The results also account for the heterogeneity in the distribution of microenterprise human capital among locations, sectors, types of business and sex.

  18. ECTOMICORRIZAS ASOCIADAS A Pinus jeffreyi EN EL PARQUE NACIONAL "CONSTITUCIÓN DE 1857" EN BAJA CALIFORNIA, MÉXICO

    OpenAIRE

    2011-01-01

    Se estudió la diversidad de hongos presentes en tres áreas boscosas del Parque Nacional Constitución de 1857 en Baja California, México. Las colectas se realizaron en agosto de 2007 y febrero, mayo y agosto de 2008, obteniendo 25 ejemplares correspondientes a tres géneros: Geastrum (cuatro especies), Suillus (una especie) y Laccaria (una especie). La abundancia de especies estuvo relacionada con la precipitación y condiciones ecológicas propias del sitio. Se realizaron muestreos para colectar...

  19. Inseguridad y Crisis Económica en el Imaginario Social de Playas de Rosarito, Baja California

    OpenAIRE

    Jesús Angel Enríquez Acosta; Alejandra Meza; Noelia Fierro

    2015-01-01

    Este trabajo ofrece un análisis acerca de como los habitantes de Playas de Rosarito en Baja California, imaginan y perciben el impacto de la crisis económica norteamericana mas reciente y la inseguridad mexicana en la actividad turística, principal vocación económica del lugar. Los testimonios de los habitantes expresan la transformación social, urbana y cultural del lugar turístico y de los problemas asociados a ciudades en rápido crecimiento. Se trata de una ciudad fronteriza con Estados Un...

  20. Diversidad de diatomeas en la dieta in situ de Chiton virgulatus (Mollusca: Polyplacophora) de Baja California Sur, México

    OpenAIRE

    David A. Siqueiros Beltrones; Uri Argumedo Hernández

    2012-01-01

    En Bahía de La Paz, Baja California Sur, se han registrado quince especies de quitones pero, en general, se descono- cen sus aspectos ecológicos básicos. Son principalmente herbívoros y observaciones preliminares sugieren que las diatomeas forman parte esencial de su alimentación por lo que el objetivo de este estudio fue determinar la diversidad de especies de diatomeas que son consumidas por Chiton virgulatus Sowerby, 1840 y si exhiben algún tipo de prefe- rencia alimentaria. Para ello se r...

  1. Problemáticas del comportamiento sexual y reproductivo de las jóvenes inmigrantes de Baja California

    OpenAIRE

    Humberto González Galbán; Germán Vega Briones

    2013-01-01

    Entre los aspectos que son analizados en el presente artículo se encuentran los vinculados a la sexualidad y la reproducción de las mujeres inmigrantes de Baja California, donde se manifiestan inequidades con relación al resto de los jóvenes, tales como las mayores afecta- ciones por enfermedades de transmisión sexual y los más altos niveles de embarazos –gene- ralmente no planificados–, lo que a su vez tiene implicaciones como una mayor frecuencia del abandono escolar, la salida involuntaria...

  2. Mapping mantle-melting anomalies in Baja California: a combined helium-seismology approach

    Science.gov (United States)

    Negrete-Aranda, R.; Spelz, R. M.; Hilton, D. R.; Tellez, M.; González-Yahimovich, O.

    2015-12-01

    In active tectonic settings, the presence of helium in aqueous fluids with 3He/4He ratios greater than in-situ production values (~0.05 RA where RA = air He or 1.4 x 10-6) indicates the contribution of mantle-derived volatiles to the total volatile inventory. This is an indicative of the presence of mantle-derived melts, which act to transfer volatiles from the solid Earth towards the surface. Thus, He has the potential to map regions of the underlying mantle which are undergoing partial melting - a phenomenon which should also be evident in the seismic record. Reports of high 3He/4He in hot springs in Baja California (BC) has prompted us to initiate a survey of the region to assess relationship(s) between He isotopes and geophysical images of the underlying mantle. Previous studies report 3He/4He ratios of 0.54 RA for submarine hot springs (Punta Banda 108oC; Vidal, 1982) and 1.3 RA for spring waters (81oC) at Bahia Concepcion (Forrest et al.,2005). Our new survey of hot springs in northern BC has revealed that all 6 localities sampled to date, show the presence of mantle He with the highest ratio being 1.74RA (21% mantle-derived) at Puertecitos on the Gulf coast. He ratios are generally lower on the Pacific coast with the minimum mantle He contribution being 5% at Sierra Juárez (0.11RA). Thus, preliminary trends are of a west-to-east increase in the mantle He signal across the peninsula. He results presented in this study correlate well with high resolution Rayleigh wave tomography images by Forsythe et al. (2007). Shear velocity variations in the BC crust and upper mantle have been interpreted as low velocity anomalies associated with dynamic upwelling and active melt production. More extensive sampling throughout BC coupled with analysis of other geochemical indicators of mantle degassing (e.g. CO2) will allow more detailed characterization of the extent and distribution of mantle melts in the region, facilitating assessment of the region's geothermal

  3. New kinematic models for Pacific-North America Motion from 3 Ma to Present, II: Evidence for a “Baja California Shear Zone”

    Science.gov (United States)

    Dixon, Timothy; Farina, Fred; DeMets, Charles; Suarez-Vidal, Francisco; Fletcher, John; Marquez-Azua, Bertha; Miller, Meghan; Sanchez, Osvaldo; Umhoefer, Paul

    2000-12-01

    We use new models for present-day Pacific-North America motion to evaluate the tectonics of offshore regions west of the Californias. Vandenburg in coastal Alta California moves at the Pacific plate velocity within uncertainties (˜1 mm/yr) after correcting for strain accumulation on the San Andreas and San Gregorio-Hosgri faults with a model that includes a viscoelastic lower crust. Modeled and measured velocities at coastal sites in Baja California south of the Agua Blanca fault, a region that most previous models consider Pacific plate, differ by 3-8 mm/yr, with coastal sites moving slower that the Pacific plate. We interpret these discrepancies in terms of strain accumulation on known on-shore faults, combined with right lateral slip at a rate of 3-4 mm/yr on additional faults offshore peninsular Baja California in the Pacific. Offshore seismicity, offset Quaternary features along the west coast of Baja California, and a discrepancy between the magnetically determined spreading rate in the Gulf Rise and the total plate rate from a geological model provide independent evidence for a “Baja California shear zone.”

  4. Eruption and magma crystallization ages of Las Tres Vírgenes (Baja California) constrained by combined 230Th/ 238U and (U-Th)/He dating of zircon

    Science.gov (United States)

    Schmitt, Axel K.; Stockli, Daniel F.; Hausback, Brian P.

    2006-11-01

    Las Tres Vírgenes volcano is a calc-alkaline composite cone located near the main Gulf of California escarpment on the E coast of the Baja California peninsula. High-sensitivity ion microprobe U-series ( 230Th/ 238U) ages for zircon from La Vírgen tephra average 121 - 10 + 12 ka (1σ; MSWD = 2.7), with discrete age peaks at ˜ 100 and 160 ka. The noble gas mass spectrometric (U-Th)/He zircon age, corrected for disequilibrium and pre-eruptive storage, is 36 ± 3 ka. This result for the eruption age of La Vírgen tephra is significantly older than previously postulated historic or Holocene ages that were based on an 18th century map reference and 14C dating of accidental charcoal, respectively. The new (U-Th)/He zircon age is consistent with a > 26 ± 4 ka age derived from cosmogenic He exposure dating of an overlying basaltic lava flow [Hausback, B.P. and Abrams, M.J., 1996. Plinian eruption of La Virgen Tephra, Volcán Las Tres Virgenes, Baja California Sur, Mexico. Eos, Transactions, American Geophysical Union, 77(46, Suppl.): 813-814.]. U-Pb zircon analysis of ignimbrites erupted from the adjacent Early Pleistocene La Reforma and El Aguajito calderas yielded ages of 1.38 ± 0.03 Ma ( n = 12; MSWD = 1.0) and 1.17 ± 0.07 Ma ( n = 23; MSWD = 1.3), respectively. No evidence for these ages is found among La Vírgen zircons, whereas pre-Quaternary zircon xenocrysts are common. The La Vírgen magma, therefore, evolved unrelated to Early Pleistocene magmatism in adjacent calderas, but assimilated local basement rocks. A gap between average Th-U and (U-Th)/He zircon ages suggests that zircon crystallization was discontinuous in the La Vírgen magma chamber. In addition, partial resorption of zircon suggests episodic thermal rejuvenation, most likely by basaltic recharge. Based on the zircon record, the > 100 ka lifetime of the thermal anomaly that sustained repeated intrusive pulses significantly exceeds the age of the last eruption. This strengthens the view that Tres

  5. Frecuencias de grupos sanguíneos e incompatibilidades ABO y RhD, en La Paz, Baja California Sur, México

    OpenAIRE

    del Peón-Hidalgo Lorenzo; Pacheco-Cano Ma Guadalupe; Zavala-Ruiz Mirna; Madueño-López Alejandro; García-González Adolfo

    2002-01-01

    Objetivo. Determinar las frecuencias génicas y de fenotipo, y predecir el riesgo de incompatibilidad y aloinmunización materna en la población de La Paz, Baja California Sur, México. Material y métodos. Estudio descriptivo en el que se evaluaron 1 809 disponentes sanguíneos altruistas que acudieron en 1998 al Hospital General de Zona, del Instituto Mexicano del Seguro Social en La Paz, Baja California Sur, México, tipificados por aglutinación en tubo. Las frecuencias génicas fueron estimadas ...

  6. Lista sistemática de los peces marinos de Bahía Magdalena, Baja California Sur (México)

    OpenAIRE

    Leonardo A. Abitia Cárdenas; Jesús Rodríguez Romero; Francisco J. Gutiérrez Sánchez; Felipe Galván Magaña; José de la Cruz Agüero

    1994-01-01

    Se proporciona el primer elenco sistemático de las especies de peces marinos del complejo lagunar de Bahía Magdalena, en Baja California Sur (México), área de gran biodiversidad, hasta ahora no estudiada de manera sistemática e integral. El listado incluye sólo las especies recolecta- das durante el desarrollo de una investigación de seis anos, las cuales están catalogadas en la colec- ción biológica del Centro Interdisciplinario de Ciencias Marinas (CIClMAR, IPN) de la Paz, Baja California S...

  7. Melampodium sinuatum (Asteraceae endémica del extremo sur de la península de Baja California en peligro de extinción Melampodium sinuatum (Asteraceae, an endangered endemic species to the southernmost tip of the Baja California Peninsula

    Directory of Open Access Journals (Sweden)

    Jose Luis Villaseñor

    2011-09-01

    Full Text Available Melampodium sinuatum Brandegee, especie endémica del extremo sur del estado de Baja California Sur, México, constituye una especie poco conocida debido a su rareza y distribución restringida. No se conoce de más de 5 sitios; todos ellos amenazados por las actividades humanas. El escaso número de individuos por población, así como la estrecha superficie que abarca su área de distribución la colocan como una especie en inminente peligro de extinción, por lo que es imperativo realizar acciones encaminadas a protegerla, las que sin lugar a dudas redundarán en beneficio de otras especies también endémicas de la región donde prospera M. sinuatum e igualmente en riesgo, debido al fuerte impacto antropocéntrico, sobre todo por actividades turísticas, y para las que no existe resguardo alguno.Melampodium sinuatum Brandegee, a species endemic to the southernmost tip of the state of Baja California Sur, Mexico, is poorly known, mostly due to its rarity and narrow geographic distribution range. Historically the species has been collected at only 5 localities and all of these are currently threatened by human activities. The scarce number of individuals per population and its narrow geographic distribution contribute to this species being critically endangered, and it is urgent to carry out activities to help it escape extinction. Without a doubt, such activities will also benefit other endemic species that grow in the vicinity and similarly lack conservation strategies to protect them from the impact of touristic activities in the region.

  8. Variación espacio-temporal de la densidad poblacional de erizo rojo Strongylocentrotus franciscanus (Echinodermata: Echinoidea: Strongylocentrotidae en Baja California Spatial and temporal variation of the population density of the red sea urchin Stronngylocenntrotus franciscanus (Echinodermata: Echinoidea: Strongylocentrotidae in Baja California

    Directory of Open Access Journals (Sweden)

    Julio S. Palleiro-Nayar

    2012-04-01

    Full Text Available Se estimó la densidad poblacional de erizo rojo, Strongylocentrotus franciscanus, en 10 localidades de la costa occidental de Baja California, México, donde se realiza la extracción comercial de este recurso pesquero. Se compararon las estimaciones realizadas en cuatro años muestreados: 2003, 2005, 2006 y 2008. Las variaciones observadas en las localidades analizadas indicaron diferencias espacio-temporales para la densidad de erizo rojo y diferencias en la estructura de tallas, las cuales estuvieron influenciadas principalmente por la intensidad de la pesca y al esporádico reclutamiento en cada sitio. Se encontraron dos localidades (Isla San Jerónimo y Arrecife Sacramento que destacaron por presentar una alta densidad de erizo rojo y una amplia estructura de tallas, predominando individuos de tallas entre 50 a 80 mm diámetro de caparazón, lo que podría indicar que la intensidad de pesca aparentemente tiene un menor efecto que en los otros sitios.Density estimations of red sea urchin Strongylocentrotus franciscanus were recorded in ten sites with commercial fisheries on the west coast of Baja California, Mexico. The estimations for the years 2003, 2005, 2006 and 2008 were compared. The variations observed in the study sites indicate important spatial and temporal differences in density and size structure, influenced by fishing intensity and sporadic recruitment in each site. We found two sites (San Jeronimo Island and Sacramento Reef with a high density and wide size structure; with a predominance of individuals of sizes from 50 to 80 mm with lest impact possible in fishing mortality for all sites.

  9. TURISMO MÉDICO EN LOS ALGODONES, BAJA CALIFORNIA, MÉXICO: EXPLORACIÓN DEL CAPITAL HUMANO

    Directory of Open Access Journals (Sweden)

    Sonia Guadalupe Zermeño-Flores

    2016-06-01

    Full Text Available El presente documento es una exploración del capital humano (CH de los profesionistas de salud respecto a la capacitación y el desarrollo de conocimientos, habilidades y actitudes en la prestación de servicios médicos al paciente-turista de Vicente Guerrero, mejor conocido como Los Algodones (LAL en el Estado de Baja California. Éste se distingue por ofrecer a los visitantes que llegan principalmente del norte de Estados Unidos y Canadá durante la temporada de invierno servicios de salud, especialmente en el campo de la higiene dental y la optometría, así como venta de medicamentos A esto se agregan las estrategias de competitividad en la frontera de Baja California (México y California (Estados Unidos. El presente artículo es tanto un estudio cuantitativo como cualitativo, que comprende tres etapas. La primera etapa consistió en la revisión de literatura del turismo médico (TM y sus implicaciones para el capital humano. La segunda etapa fue la consulta de datos básicos de la entidad, que se sometió al análisis estadístico de los profesionistas instalados oficialmente en las empresas que operan en el TM. La tercera etapa se enfocó en la realización de entrevistas a profundidad a profesionistas de la salud de alto prestigio en la sociedad de Los Algodones.

  10. Sonora, Mexico, source for the Eocene Poway Conglomerate of southern California

    Science.gov (United States)

    Abbott, Patrick L.; Smith, T. E.

    1989-04-01

    Alluvial-fan conglomerates of the Eocene Poway Group are composed largely of exotic rhyolite and dacite clasts derived from far to the east of their Eocene depositional site. Remnants of the Upper Jurassic bedrock source of the Poway rhyolite clasts may yet be exposed in hills in Sonora, Mexico. For this study, pieces of bedrock were taken from hills 13 km west of El Plomo in Sonora. Clasts texturally and mineralogically similar to the Sonoran bedrock were collected from the apex of the Eocene alluvial fan in San Diego County, California Nine couplets of bedrock and conglomerate clast samples (textural twins) were analyzed for 16 trace elements selected for their wide range of behaviors during magmatic and alteration processes. Statistical comparisons of the trace-element data, by using the standard error-of-the-difference method, show that there are no significant differences between the two populations. These data strongly suggest that the rhyolitic bedrock hills west of El Plomo were part of the source terrane for the Eocene conglomerate in San Diego. The latitudinal separation between bedrock source and the site of deposition is only the 2° created by the opening of the Gulf of California This implies that any boundary separating a paleomagnetically efined, Baja-Borderland terrane from the craton since Eocene time was at least 100 km east of the Gulf of California in northernmost Sonora.

  11. Net primary productivity, upwelling and coastal currents in the Gulf of Ulloa, Baja California, México

    Directory of Open Access Journals (Sweden)

    E. González-Rodríguez

    2012-08-01

    Full Text Available The Gulf of Ulloa, a highly productive area off the western coast of the Baja California Peninsula, is examined for five successive years (2003–2007 by using satellite data and seasonal net primary productivity (NPP estimates obtained from a vertical generalised production model. The results identify that northwestern winds blow parallel to the coast throughout the year. However, highest NPP occurs from March to June. During this period, an equatorward coastal current transports water from neighbouring upwelling areas to the northern Gulf of Ulloa and in combination with local upwelling, which injects nutrients into the euphotic zone, produce the observed increase in NPP. The opposite situation occurs in late summer when a warm poleward current of tropical characteristics arrives and inhibits the productivity in the whole region and generates the yearly lowest NPP levels. Our findings reveal the importance of lateral advection in the modulation of the primary productivity in this subtropical upwelling region.

  12. Business competitiveness in the small and medium-sized enterprises of the manufacturing sector in Baja California

    Directory of Open Access Journals (Sweden)

    Manuel Alejandro Ibarra Cisneros

    2017-01-01

    Full Text Available The objective of this research is to determine the competitiveness level of the manufacturing small and medium-sized enterprises (SMEs of Baja California and to identify which areas within them affect this competitiveness. The methodology used is descriptive, correlational, and cross-sectional; the systemic competitiveness model is developed at the micro level, and a measurement instrument with 64 questions is used on 195 companies in the state; in addition, traditional multiple linear regressions are performed to test the hypotheses. One of the findings is that the SMEs in the state have a medium-low competitiveness level and do not show any relationship between the size of the companies and their competitiveness; however, the production-operations area prove to be more important for their competitiveness level. Although the measurement instrument that is used has no proportionality at the municipality and subsector level, it does allow us to approach the internal operation of the SMEs.

  13. Los matices regionales de la división de poderes: Baja California y Coahuila en perspectiva comparada

    OpenAIRE

    Paola Carmina Gutiérrez Cuéllar; Alejandro Monsiváis Carrillo

    2011-01-01

    El propósito de este artículo es analizar las políticas de la división de poderes en Baja California y Coahuila, para ello se presenta un índice de equilibrio entre poderes estatales, que permite observar su grado de concentración o dispersión, promovido por el diseño constitucional. También se exploran las condiciones políticas de las interacciones entre los poderes públicos en dichos estados. Se mostrará que, tanto en el diseño constitucional como en la operación fáctica de la política exis...

  14. Riesgo de contaminación del acuífero arroyo Alamar en Tijuana, Baja California

    Directory of Open Access Journals (Sweden)

    Marnie González Estévez

    2013-01-01

    Full Text Available El acuífero del arroyo Alamar, en Tijuana, Baja California, es uno de los escasos suministros de agua con que cuenta esta ciudad. En el área que recorre el Alamar se realizan actividades que, aunadas a la falta de medidas de control y vigilancia, inciden en la contaminación del lugar. De acuerdo con las fuentes contaminantes examinadas en el presente estudio, aquí se presentan resultados de un ejercicio de evaluación del riesgo de contaminación al que está expuesto el acuífero, mediante la interacción entre la vulnerabilidad intrínseca y la carga contaminante a la que está siendo sometido; dicha carga se encontró en aproximadamente la mitad de su área.

  15. Trabajadores agrícolas migrantes en Baja California. Vinculación con la migración internacional

    Directory of Open Access Journals (Sweden)

    Ma. Eugenia Anguiano Téllez

    1989-09-01

    Full Text Available En este ensayo los jornaleros agrícolas migrantes son clasificados en dos estratos: el primero, considera la migración internacional, es decir, aquéllos que se internan en Estados Unidos con el propósito de conseguir empleo; y el segundo, corresponde a la migración interna de los trabajadores agrícolas que permanecen en Baja California para laborar en los valles de Mexicali y San Quintín.En este trabajo se señalan las diferencias entre estos dos estratos, tanto de carácter económico como en los niveles de educación; asimismo, se comparan las características de los jornaleros agrícolas migrantes que cruzan a Estados Unidos por Mexicali y por Tijuana, según su actividad económica de procedencia y su expectativa de empleo en los Estados Unidos.

  16. Estudio de algunos procesos pedogenéticos en el valle de Ojos Negros, Baja California, México

    Directory of Open Access Journals (Sweden)

    Francisco Raúl Venegas Cardoso

    2005-01-01

    Full Text Available El estudio sistemático de suelos en Baja California, México, ha sido pobremente desarrollado. Solamente se han encontrado algunos reportes en la literatura científica, realizados en el Desierto Central. El objetivo de este trabajo es estudiar los procesos pedogenéticos que han permitido el desarrollo de los suelos en el valle de Ojos Negros, Baja California, bajo un ambiente mediterráneo. Para el estudio se utilizó el método jerárquico propuesto por Zinck (1988. Se estableció un ambiente morfogenético de naturaleza deposicional que permitió separar cuatro paisajes; lomeríos piedemonte, planicie de nivel de base y valle fluvial, los que fueron subdivididos por relieve/modelado y por características litológicas y sus correspondientes unidades de suelos a nivel de Gran Grupo de acuerdo con el Soil Survey Staff (1992. Estos suelos se formaron bajo diferentes ambientes, materiales, condiciones climáticas, con periodos glaciares e interglaciares de sequía y humedad. Estos procesos se iniciaron desde el Plioceno y continúan en la actualidad, manifestándose en su pedogénesis. Algunos han desarrollado horizontes Bt rojos sobre esquistos y gneiss, (Rhodoxeralfs, otros desarrollados sobre detritos graníticos, presentan un pobre desarrollo (Xeropsamments; materiales graníticos con procesos coluvio-aluvial han formado suelos poligenéticos, horizontes C, con la presencia de horizontes Bt rojos (4CBt, arcilla heredada y hierro amorfo (Haploxeralfs. Algunos otros manifiestan influencia gley (Cegz1, Gley1 6/5GY, Fluvaquents. Los procesos de erosión, transporte y acumulación de materiales en las tierras bajas continúan a la fecha, asimismo, la presencia de un proceso relativamente reciente: materiales que están siendo redistribuidos por el viento y depositados sobre diques de metarriolita, provocado por las condiciones de sequía en toda la región.

  17. Isla Guadalupe, Mexico (GUAX, SCIGN/PBO) a Relative Constraint for California Borderland and Northern Gulf of California Motions.

    Science.gov (United States)

    Gonzalez-Garcia, J. J.

    2004-12-01

    Using ITRF2000 as a common reference frame link, I analyzed survey mode and permanent GPS published results, together with SOPAC public data and results (http://sopac.ucsd.edu), in order to evaluate relative present day crustal deformation in California and northern Mexico. The crustal velocity field of Mexico (Marquez-Azua and DeMets, 2003) obtained from continuous GPS measurements conducted by Instituto Nacional de Geografia e Informatica (INEGI) for 1993-2001, was partially used. The preferred model for an instantaneous rigid motion between North-America and Pacific plates (NAPA), is obtained using results of Isla Guadalupe GPS surveys (1991-2002) giving a new constraint for Pacific plate (PA) motion (Gonzalez-Garcia et al., 2003). It produces an apparent reduction of 1 mm/yr in the absolute motion in the border zone between PA and North-America (NA) plates in this region, as compared with other GPS models (v.g. Prawirodirdjo and Bock, 2004); and it is 3 mm/yr higher than NNRNUVEL-1A. In the PA reference frame, westernmost islands from San Francisco (FARB), Los Angeles (MIG1), and Ensenada (GUAX); give current residuals of 1.8, 1.7 and 0.9 mm/yr and azimuths that are consistent with local tectonic setting, respectively. In the NA reference frame, besides the confirmation of 2 mm/yr E-W extension for the southern Basin and Range province in northern Mexico; a present day deformation rate of 40.5 mm/yr between San Felipe, Baja California (SFBC) and Hermosillo, Sonora, is obtained. This rate agrees with a 6.3 to 6.7 Ma for the "initiation of a full sea-floor spreading" in the northern Gulf of California. SFBC has a 7 mm/yr motion in the PA reference frame, giving then, a full NAPA theoretical absolute motion of 47.5 mm/yr. For Puerto Penasco, Sonora (PENA) there is a NAPA motion of 46.2 mm/yr and a residual of 1.2 mm/yr in the NA reference frame, this site is located only 75 km to the northeast from the Wagner basin center. For southern Isla Guadalupe (GUAX) there

  18. Mexican waterfowl survey 1974, west coast of Baja California and the mainland south to Culiacan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This survey is an extension of Annual Midwinter Survey of waterfowl conducted in the United States and southern Canada. By embracing only selected regions of Mexico...

  19. Hydrography of Bahia Todos Santos, Baja California: Results of more than twenty five years of investigations.

    Science.gov (United States)

    Bustos-Serrano, H.; Canino-Herrera, S. R.; Morales-Chavez, R.; Martinez-Garcia, G. M.

    2007-05-01

    The first study of Bahia Todos Santos (BTS) was reported by Walton in 1955. We conducted oceanographic studies in BTS since 1979. The BTS has a connection with a coastal lagoon named Estero de Punta Banda (EPB), two islands at the western portion and the Port of Ensenada. The general hydrographic characteristics are: In winter the water became homogeneous, less saline (33.6) low temperature (13°C), low oxygen (~3mL L-1) and rich in nutrient concentration. The isothermal top layer has relatively high temperature (>17°C) and oxygen concentration (>6mL L-1). The intermediate transition layer (seasonal thermocline) has minimum salinity, maximum oxygen and high stability. During fall there is distribution of heat from the surface layer to the entire water column. The thermic waves propagate with decrease amplitude in ~3 months, from surface to bottom water. The California Current flow generally southward off the western United States and northern Mexico and is one of the major coastal upwelling of the word oceans. The upwelling events in BTS appear regularly at the SW portion and were typically characterized by an increase in pCO2, decrease of O2, increase of nutrients and a lower temperature. Upwelling activity increases surface nutrient availability causing rise in the primary productivity and hence increased zooplankton biomass. The annual upwelling event which had a maximum strength on May, the seasonal warming and cooling, and the water advection were the dominant modifying processes for the variability of seawater characteristics. Higher salinities are located close to the coastline and lower off the bay. The levels of oxygen, alkalinity, pH and chlorophyll indicate that the maximum concentration of phytoplankton is located at the center of the bay. The nitrification support the primary productivity and the NO3 levels were below detection limits; the N/P ratio in 2005 was from 10 to 25; and for 2006 was below 5. There is a net enrichment of anthropogenic

  20. Reprobación en las carreras del área de Ciencias de la Salud de la Universidad Autónoma de Baja California, México

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    Elías Torres Balcázar

    2015-10-01

    Full Text Available Esta investigación explora las causas de reprobación de los estudiantes del segundo semestre de las carreras del área de la Salud (Medicina, Enfermería y Actividad Física y Deportes de la Universidad Autónoma de Baja California, en Ensenada, Mexico. Se identificaron 49 estudiantes reprobados con quienes se realiz6 un diseño investigativo de carácter exploratorio-descriptivo, cuyos resultados permitieron determinar que las principales causas de reprobación se debieron al desempeño academico de los estudiantes, deficiencias en las tecnicas de estudio, poca dedicaci6n a las actividades académicas y el nerviosismo que les provoca enfrentarse a los exámenes. A lo anterior se agrega que la mayor parte no acude al docente para aclarar dudas. A partir de estos resultados, se sugieren diversas estrategias para resolver el problema de reprobación. AbstractThis paper explores causes of failure in students of second semester in Health Program careers (Medicine, Nursing, Physical Activity and Sports at Universidad Autonoma de Baja California, in Ensenada, Mexico. 49 students who failed were identified; they were applied an exploratory and descriptive research design, whose results allowed to determine that the major causes of failure were due to the students’ academic performance; deficient study techniques; little time for academic activities; and stress before term exams. In addition to the aforementioned reasons, most of the students do not ask the teacher to clarify doubts. From these results, a variety of strategies are recommended in order to avoid failures in the Health Program.

  1. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in October 2006

    Science.gov (United States)

    2007-06-01

    15. 16. 17. 18. 19. Reginaldo Durazo Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn...Tim Boyer NOAA (NODC) Washington, DC Carmen G. Castro Consejo Superior de Investigaciones Científicas Spain Newell Garfield San Francisco

  2. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in November 2010

    Science.gov (United States)

    2011-09-20

    Landing, CA Frank Schwing NOAA Pacific Grove, CA Reginaldo Durazo Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn... Carmen G. Castro Consejo Superior de Investigaciones Científicas Spain Newell Garfield San Francisco State University San Francisco, CA

  3. Genetic damage and exposure to pesticides among agricultural workers from Valle de San Quintín, Baja California, México

    Directory of Open Access Journals (Sweden)

    Erika Zúñiga Violante

    2012-12-01

    Full Text Available Various studies have shown the ability of pesticides to induce genetic damage (GD that can cause health effects. In the present work, a genotoxicological study was conducted monitoring residents from the agricultural region of the San Quintin Valley (SQV, Baja California, Mexico. The objective was to determine if occupational and environmental exposure to pesticides in the region of the SQV is a factor in GD, and to find out if women are more vulnerable to this effect. A questionnaire was administered to 88 residents of the SQV to establish inclusion and exclusion criteria for the study; of these, 40 agreed to participate (25 occupationally exposed to pesticides and 15 environmentally exposed to them, with similar numbers of men and women. All participants signed an informed consent form. The micronuclei technique (MN was used, which blocks cytokinesis in peripheral blood samples, to evaluate GD by counting the number of MN and Chromatin Bridges in 1000 bi-nucleated cells (BNC. The results of this measure of genetic damage were then correlated with the degree of occupational pesticide exposure of the participants. Environmentally exposed men had less GD than women with MN means of 8.1± (1.83 and 13.1(±1.7 respectively, whereas occupational exposure affected both sexes, men with a mean of MN equal to 15.9 (± 2.9, and women with 18.12 (± 1.7. Based on our results, it can be concluded that occupational exposure to pesticides is a factor in GD, with women showing greater vulnerability than men. The time of exposure at work was shown to be directly related to the increased number of MN.

  4. Spectral Analysis of Pore Pressure Data Recorded from the 2010 Sierra EL Mayor (baja California) Earthquake at the NEES@UCSB Wildlife Field Site

    Science.gov (United States)

    Seale, S. H.; Lavallee, D.; Steidl, J. H.; Ratzesberger, H.; Hegarty, P.

    2010-12-01

    On 4 April 2010, the M7.2 Sierra el Mayor event occurred in Baja California, Mexico. The NEES@UCSB Wildlife field site in the Imperial Basin is located 110 km NNW of the hypocenter. The event was recorded on all channels: by three-component strong-motion accelerometers at the surface and in boreholes at various depths and by pore pressure transducers located in a saturated, liquefiable layer. We have computed the spectra of the pore pressure response in the frequency domain for signals recorded at different depths. At each depth, the spectrum is attenuated as a power law with a sharp discontinuity at a frequency close to 1 Hz. We report the value of the exponents that characterize the power-law behavior of these spectra. We also computed cross-spectral analysis of the pore pressure records from different depths. The functional behaviors of the curves of the cross-spectra are similar to that of the original spectra. For comparison, we present the spectrum of each component of the ground motion recorded at a nearby accelerometer. Partially due to the late arrival of the surface waves, the frequency content of the recorded pore pressure signal is a function of time. To gain a better understanding of the time-dependence of the frequency content, we performed spectral analysis of the signal in a moving window and wavelet transforms of the full signals. The spectral analysis suggests that, except for high frequencies, the curves exhibit a complex behavior as a function of the window position. We interpret and discuss the consequences of the estimated spectra, the cross-spectra, and the wavelet transforms.

  5. Geoelectrical analysis of Las Tres Virgenes geothermal zone, Baja California Sur, Mexico. Analisis geoelectrico de la zona geotermica de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Bigurra Pimentel, Emilio (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico))

    1998-01-15

    On the basis of vertical electric sounding (VES) analysis it is possible to define three geoelectrical environments in Las Tres Virgenes geothermal area. From the surface to 250 m depth, apparent resistivity values change from 12000 Ohm.m. to 200 Ohm.m. This layer is composed by Las Tres Virgenes volcanic material, Aguajito ignimbrite and Santa Rosalia basin deposits. Underlaying this high resistivity layer, from 250 m to 1500 m depth, there is an extensive conductive layer with low resistivity values from 15 Ohm.m to 3 Ohm. m. This conductive layer includes the aquifer of the area, the Santa Lucia and Comondu formations and the top of granitic basement. Under this low resistivity layer, there is a zone of medium resistivity values from 20 Ohm.m to 100 Ohm.m, corresponding to El Azufre and El Partido volcanoes area, and the Agua Caliente hydrothermal zone. The decrease of resistivity values in this middle resistivity layer is associated with hot rock zones produced by magmatic intrusions (volcanoes zone). High horizontal gradients are associated with geologic faults with normal component of fractures, and high vertical gradients with changes in electrical layers, some of them with superficial evidences, but other appearing only at depth. The intersection of NW-SE with NE-SW trends are important, because those zones provide the paths for the hydrothermal fluids circulation; examples of these zones are: Los Azufres volcano area, El Partido volcano and Agua Caliente geothermal zone.

  6. Cobertura con calidad a través de la reorganización institucional en la educación superior de Baja California

    Directory of Open Access Journals (Sweden)

    Patricia Moctezuma

    2013-01-01

    Full Text Available En este trabajo se demuestra que el crecimiento y consolidación del Sistema Estatal de Educación Superior de Baja California (sees, entre 2000 y 2010, es resultado de los esfuerzos de las instituciones de educación superior (ies públicas por consolidar la calidad a través del cambio organizacional y la acreditación de programas educativos más que de la política de diversificación a través de la educación particular. Esto se ejemplifica con la experiencia de cambio organizacional y el crecimiento de la cobertura generados desde la Universidad Autónoma de Baja California (uabc.

  7. Participación ciudadana en la evaluación de la política de seguridad pública: el caso de Baja California

    OpenAIRE

    2003-01-01

    En este artículo se destaca la importancia de la participación de la ciudadanía en los procesos de evaluación de las políticas de seguridad pública en Baja California, como una manifestación de la necesidad de establecer nuevas formas de gestión pública, en las cuales se establezcan relaciones de corresponsabilidad entre sociedad y gobierno.

  8. Valoración socioambiental de los recursos naturales: el caso de los recursos minerales en la parte central de Baja California Sur, México

    OpenAIRE

    Luis F. Beltrán Morales; Víctor Sevilla Unda; Macià Blázquez Salom; Federico Salinas Zavala; Felipe García Rodrígez

    2005-01-01

    Se seleccionaron 15 localidades ubicadas en el radio de influencia de dos depósitos evaluados de fosfato, esto con la finalidad de aplicar el método de valoración contingente del recurso y su medio ambiente: el depósito de Tembabichi en el margen del Golfo de California y el depósito de Santo Domingo en la costa del Pacífico en Baja California Sur, México. Se encontró una disposición media a pagar por los habitantes del área de estudio de $29.77 pesos mensuales para colaborar con ...

  9. Perros ferales en la isla de Cedros, Baja California, México: una posible amenaza para los pinnípedos

    OpenAIRE

    María Concepción García-Aguilar; Juan Pablo Gallo-Reynoso

    2012-01-01

    La presencia de perros ferales (Canis lupus familiaris) en la isla de Cedros, Baja California, México, fue documentada hace más de 15 años. En el verano de 2009 e invierno 2009/2010, se realizaron 2 campañas de muestreo en la costa noreste de la isla para evaluar los hábitos alimentarios de los perros en las cercanías de las zonas de reproducción y descanso del lobo marino de California (Zalophus californianus) y del elefante marino del norte (Mirounga angustirostris). Los mamíferos constituy...

  10. Tropical-Depression Precipitation In Southwestern North America: An Isotope Record From Arizona, And Isotope Signatures In Baja California Groundwater

    Science.gov (United States)

    Eastoe, C. J.; Hess, G.; Mahieux, S.

    2011-12-01

    A 30-year data set of O and H isotopes in individual precipitation events in Tucson, Arizona, includes entries identified with rainfall associated with tropical depressions, which occasionally pass through southern Arizona. Tropical-depression rain events yielding > 7 mm have a δ18O range -9 to -16 per mil, compared to volume-weighted average summer rainfall with δ18O = -6 per mil, a set of isotope effects similar to those observed in south Texas. The isotope signature of tropical-depression rain is present in groundwater of central and southern Baja California (BC), where summer and fall rain make up at least 50% of annual precipitation. Tritium-bearing groundwater at Todos los Santos (southern BC) has a δ18O range of -8 to -11 per mil and d-parameters near 10. Altitude effects related to adjacent, 1800 m mountains do not explain the isotope data. Groundwater of similar isotope character is present near the Tres Virgenes geothermal field (central BC), but not at Santo Tomas (northern BC). Large deuterium excess (d > 15) is not observed in any of the data.

  11. Diagnóstico socioambiental como fundamento para una estrategia de educación ambiental en Colonet, Baja California

    Directory of Open Access Journals (Sweden)

    Rosa Hidemi Ortega Armenta

    2012-01-01

    Full Text Available Colonet, Baja California, es una comunidad rural localizada en una zona árida, donde existe la propuesta de construir un megaproyecto portuario. Ahí se realizó un diagnóstico socioambiental, con el fin de identificar la problemática actual del medio ambiente y posibles soluciones, a través del análisis de la percepción social y las amenazas ambientales. El desabasto de agua se percibe como el problema principal debido a factores sociales y políticos, y las prácticas agrícolas se identificaron como la amenaza ambiental primordial. Estos resultados demuestran la necesidad de mejorar la organización comunitaria, con base en mayor y mejor información. Se identificaron las soluciones y se diseñaron cuatro escenarios. Aquí se propone una estrategia de educación ambiental, que fomente la organización y participación informada en la comunidad, para lograr la tecnificación agrícola orgánica y la gestión integrada de recursos hídricos.

  12. Satisfacción turística del visitante fronterizo en Baja California, México

    Directory of Open Access Journals (Sweden)

    Nora L. Bringas Rábago

    2016-01-01

    Full Text Available La evaluación de la satisfacción del visitante internacional constituye uno de los campos más prolíficos y efervescentes de la investigación turística, por el carácter abstracto y multidimensional instrumentado. Con el apoyo de datos levantados en los puertos fronterizos del estado de Baja California, México, en este trabajo se examinó la explicación de los atributos de la satisfacción y sus relaciones causales, por medio de la propuesta de un modelo teórico. Para llevar a cabo el análisis se evaluaron los modelos de medidas y el estructural, que permitieron fijar los niveles de significación de las relaciones causales que le dieron forma y fondo al modelo teórico propuesto. Los resultados arrojaron que la relación calidad-precio y el consumo de alimentos y bebidas constituyen las dimensiones que más explicaron la estructuración de la satisfacción en los destinos visitados.

  13. Inseguridad y Crisis Económica en el Imaginario Social de Playas de Rosarito, Baja California

    Directory of Open Access Journals (Sweden)

    Jesús Angel Enríquez Acosta

    2015-01-01

    Full Text Available Este trabajo ofrece un análisis acerca de como los habitantes de Playas de Rosarito en Baja California, imaginan y perciben el impacto de la crisis económica norteamericana mas reciente y la inseguridad mexicana en la actividad turística, principal vocación económica del lugar. Los testimonios de los habitantes expresan la transformación social, urbana y cultural del lugar turístico y de los problemas asociados a ciudades en rápido crecimiento. Se trata de una ciudad fronteriza con Estados Unidos donde el turismo asociado al consumo de alcohol y entretenimiento de fin de semana y el turismo de segundas residencias dirigido al norteamericano es dominante. El contexto de la crisis económica, la inseguridad reinante en México condujeron a un decaimiento de la actividad turística y a una sensación de incertidumbre y pesar a los habitantes de esta comunidad.

  14. Gobiernos de coalición: un nuevo diseño institucional en el Congreso de Baja California

    Directory of Open Access Journals (Sweden)

    Cuauhtémoc López Guzmán

    2014-01-01

    Full Text Available Este trabajo analiza la relación entre poderes en Baja California; no se fundamenta en las teorías de la representación, sino en la Teoría de la Elección Racional, sitúa a los actores políticos individuales como entes egoístas, maximizadores e instrumentales al estructurar conductas bajo el principio de mejor ganancia y menor pérdida. La metodología empleada combina el modelo de elección racional y el neoinstitucionalismo en la vertiente de la Teoría de los Costos de Transacción Política. Para concluir, se enfatiza que los componentes conductuales y representativos de todo legislador se asocian a un dilema enfrentado por la disciplina partidista versus la responsabilidad legislativa. Estos comportamientos opuestos son analizados para identificar la viabilidad del modelo de un gobierno de coalición.

  15. Problemáticas del comportamiento sexual y reproductivo de las jóvenes inmigrantes de Baja California

    Directory of Open Access Journals (Sweden)

    Humberto González Galbán

    2013-01-01

    Full Text Available Entre los aspectos que son analizados en el presente artículo se encuentran los vinculados a la sexualidad y la reproducción de las mujeres inmigrantes de Baja California, donde se manifiestan inequidades con relación al resto de los jóvenes, tales como las mayores afecta- ciones por enfermedades de transmisión sexual y los más altos niveles de embarazos –gene- ralmente no planificados–, lo que a su vez tiene implicaciones como una mayor frecuencia del abandono escolar, la salida involuntaria del hogar paterno así como otras problemáticas familiares, todo lo que incide negativamente en la salud de las jóvenes migrantes y en sus condiciones de vida en general. La atención médica, que puede contribuir a atenuar efec- tos no deseados de dicha situación, también es recibida en menor medida por las jóvenes inmigrantes, lo que conjuntamente con las desventajosas condiciones socioeconómicas en que viven y/o el contar, en un menor grado, con redes familiares y sociales de apoyo, las convierte en una población más vulnerable y necesitada de trabajo comunitario que atienda sus problemáticas sexuales y reproductivas.

  16. Coastal dynamics off Cabo Pulmo, Baja California Sur, México

    Science.gov (United States)

    Trasviña-Castro, A.; Gonzalez-Rodriguez, E.; Zaitsev, O. V.

    2013-05-01

    Cabo Pulmo is the one of the few coral reefs of the Mexican Pacific. It is located to the north of the Tropic of Cancer (at 23.5° N) and therefore formally in the subtropical region. It is part of the Gulf of California but its location near the tip of the Peninsula pose questions about the exchange of properties with the neighboring Pacific Ocean, some of which will be addressed here. It was declared National Park in 1995. Since then it became a no-take zone and a nature reserve for the preservation of the large variety of species found there. We report results based on meteorological and hydrographic observations as well as current measurements gathered between October 2010 and February 2012. These results include the presence of coastal currents forced by the tide, the wind and remote forcing. We believe the latter are associated, sometimes, to the mesoscale circulation of the entrance to the Gulf of California and, at other times, to coastal jets coming from the interior of the Gulf. We use displacement diagrams to discuss the trends of the residual circulation along the coast. During autumn, winter and even in spring the residual coastal flow is towards the Equator. This is attributed to the influence of the Northwesterly winds that blow over the Gulf of California in these months. It is in summer that the coastal residual circulation exhibits a poleward component being more intense during Southeasterly wind events. Finally, we present evidence of coastal exchange with the Pacific Ocean in the form of an intense jet. This coastal jet flows equatorward past Cabo Pulmo, continues towards the Pacific side of the Peninsula and generates offshore filaments when turning the cape.

  17. [Bycatch fish species from shrimp industrial fishery in the Gulf of California, Mexico].

    Science.gov (United States)

    López-Martínez, Juana; Herrera-Valdivia, Eloisa; Rodríguez-Romero, Jesús; Hernández-Vázquez, Sergio

    2010-09-01

    Bycatch fish species from shrimp industrial fishery in the Gulf of California, Mexico. The shrimp fishery in the Gulf of California is one the most important activities of revenue and employment for communities. Nevertheless, this fishery has also created a large bycatch problem, principally fish. To asses this issue, a group of observers were placed on board the industrial shrimp fleet and evaluated the Eastern side of the Gulf during 2004 and 2005. Studies consisted on 20kg samples of the capture for each trawl, and made possible a systematic list of species for this geographic area. Fish represented 70% of the capture. A total of 51 101 fish were collected, belonging to two classes, 20 orders, 65 families, 127 genera, and 241 species. The order Perciformes was the most diverse with 31 families, 78 genera, and 158 species. The best represented families by number of species were: Sciaenidae (34) and Paralichthyidae (18) and Haemulidae and Carangidae (16 each). The best represented genera in number of species were Symphurus (nine) and Diplectrum and Cynoscion (six); other important genera were Larimus and Porichthys with five species each. The best represented species in number were Syacium ovale, Pseudupeneus grandisquamis, Haemulopsis nitidos, Diplectrum pacificum, Synodus scituliceps, Balistes polylepis, Eucinostomus currani, Eucinostomus gracilis, Porichthys analis, Chloroscombrus orqueta, Selene peruviana, Orthopristis reddingi, Etropus crossotus, Scorpaena sonorae and Urobatis halleri. The number of recorded species is notably high, compared with demersal fauna of other areas of the Mexican Pacific, such as Gulf of Tehuantepec (178), Nayarit, Michoacán, Guerrero (174, 120 and 166), Jalisco and Colima (161 species), and those of the Western coast of the Baja California Peninsula (220 species).

  18. Efecto de los vientos Santa Ana en las propiedades bio-ópticas frente a Baja California

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available A partir de las propiedades bio-ópticas, los coeficientes de absorción por partículas, detritos y fitoplancton (ap, adT, aφ se evaluó el efecto de los vientos Santa Ana en el océano frente a Baja California ocurridos durante octubre de 1999. Los vientos medidos en la estación meteorológica frente a la Bahía de Todos Santos y los determinados a partir de información de satélite indicaron tres eventos Santa Ana, caracterizados por baja humedad relativa, alta temperatura del aire y vientos con dirección predominante del este-noreste. Los valores del coeficiente de absorción de detritos (adT fueron hasta diez veces mayores en las muestras superficiales de octubre, con relación a las de enero, abril y agosto de 1999. Los altos valores de adT se debieron al material inorgánico aero-transportado por los vientos tierra-mar ocurridos del 9 al 11 y del 17 al 20 de octubre. Los coeficientes de absorción de las particulas (ap y el fitoplancton (aφ en la zona eufótica fueron mayores en abril, como resultado de la abundancia del fitoplancton. Los valores de ap, aφ y Kd para la zona eufótica fueron ajustados a una función de potencia con la clorofila como variable independiente, con una variancia explicada de 37%, 72% y 16%, respectivamente. Cuando se excluyeron del ajuste los valores de adT medidos en la superficie durante octubre, la clorofila explicó 82% de la variabilidad en los coeficientes de absorción (ap y aφ y 87% en Kd. A partir de la ecuación que relaciona la reflectancia de la radiancia espectral ascendente (Rrs con la clorofila, se determinó que ~80% de la variabilidad en la clorofila superficial es explicada por la razón de reflectancia Rrs(443/Rrs(555 medida en la zona de estudio. Las estimaciones regionales de clorofila a partir de información bioóptica obtenida en la columna de agua no fueron afectadas fuertemente por el polvo aero-transportado durante los vientos Santa Ana ocurridos en octubre de 1999.

  19. 75 FR 64681 - Pistachios Grown in California, Arizona, and New Mexico; Continuance Referendum

    Science.gov (United States)

    2010-10-20

    ...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 983 Pistachios Grown in California..., Arizona, and New Mexico pistachio producers to determine whether they favor continuance of the marketing order regulating the handling of pistachios grown in California, Arizona, and New Mexico. DATES:...

  20. Interpreting the seasonality of precipitation in northern Baja California for the last ~45,000 cal yr BP

    Science.gov (United States)

    Chavez, V.; Brunelle, A.; Brewer, S.

    2014-12-01

    The Sierra de Juarez of Northern Baja California lies in a region that is heavily influenced by the El Niño Southern Oscillation (ENSO), which brings winter precipitation and the North American Monsoon (NAM), which brings summer precipitation to the region. Little is known about the impacts that the seasonality of precipitation have had on fire and vegetation throughout the region, especially extending into the early Holocene and Pleistocene. Fire regimes and ciénega processes, as indicate by loss on ignition, magnetic susceptibility, and charcoal data, appear to be controlled by the amount of precipitation to the region and groundwater levels. This study will analyze seasonality of precipitation based on certain taxa that are associated with summer wet or winter wet moisture patterns. Preliminary pollen analysis shows that when summer-wet taxa are more prevalent on the landscape, winter-wet taxa declines. Based on existing ENSO and NAM data, we know that the influences of both phenomena have changed in their intensities and spatial boundaries throughout time. Our study sites (Ciénega Chimeneas, 32o 14' N and 116 o 06' W, and Ciénega San Faustino, 32° 12' 30.4" N 116° 09' 55" W, spanning the last ~45,000 cal yrs BP) are located in a region that can help define when and where changes in the seasonality of precipitation have occurred since the late Pleistocene. Additional dating and pollen analysis will allow us to further validate the relationships between ENSO and NAM like activity and ecosystem processes for this site.

  1. Transient thermal regimes in the Sierra Nevada and Baja California extinct outer arcs following the cessation of Farallon subduction

    Science.gov (United States)

    Erkan, Kamil; Blackwell, David

    2009-02-01

    We examine the thermal relaxation of the Sierra Nevada and Baja California extinct outer arc blocks following the progressive cessation of Farallon subduction under western North America beginning at ˜30 Ma. Being parts of the same outer arc until the inland jump of the San Andreas transform fault at ˜5 Ma, these two regions show many similarities in their geology, geomorphology, rigid body behavior, and their relatively low seismicity. In the thermal model, we combine results of different geophysical and geophysical studies to constrain the thermal state and geometry of the outer arcs before the cessation of subduction and then model the postsubduction temperature responses in these regions using the results of the tectonic reconstructions. A well-constrained regional thermal model of these blocks using the results of many earlier studies in these regions confirms that the present low heat flow values in these regions are the remnants of the very cold outer arc thermal regime of the subduction zone even as long as 30 Ma after cessation of subduction. Thus the entire Pacific boundary of the North American plate is still in a transient thermal state. The calculated low lithospheric temperatures in the Sierra Nevada and Peninsular blocks correlate very well with their rigid body behavior obtained from geodetic studies, and seismogenic layer thicknesses obtained from seismological studies. This is in contrast with the fact that both regions are surrounded by intense deformation associated with the western North America intraplate and extraplate motions. These low-temperature islands play important roles in the present interaction of the North American and Pacific plates and contribute to the broad deformation of the transform boundary. The thermal relaxation of the extinct outer arcs includes both vertical heating from the underlying asthenosphere and the lateral heating from the extinct back arc (Basin and Range), which has remained as a high heat flow region after

  2. Analysis of two catalogues of seismicity at the Cerro Prieto geothermal area (Baja California) from 1988 to 1995, relationship with reinjection; Analisis de dos catalogos de sismicidad en el area geotermica de Cerro Prieto (Baja California) de 1988 a 1995, relacion con la reinyeccion

    Energy Technology Data Exchange (ETDEWEB)

    Fabriol, Hubert [Centro de Investigacion y de Ensenanza Superior de Ensenada (CICESE), Ensenada (Mexico)

    1996-09-01

    California) (EU) y la Red Sismologica del Noreste de Mexico (RESNOM) of the Centro de Investigacion Cientifica y de Ensenanza Superior (CICESE, Mexico) a partir de 1988. La precision de las localizaciones de ambos catalogos son estimadas con base en las localizaciones de eventos moderados calculadas con una red local, instalada alrededor de Cerro Prieto a partir de agosto 1994. Se nota un sesgo en ambos catalogos, que desplaza los eventos entre 5 y 10 km hacia el sur para USGS-Caltech, y entre 4 y 8 km hacia el noreste para RESNOM. Esto limita el uso de los catalogos para estudios precisos de los efectos de la reinyeccion en el campo geotermico. La actividad sismica es baja hasta 1991 y aumenta despues, en particular en 1993 y 1995. La comparacion del catalogo de USGS-Caltech con las variaciones de los gastos de reinyeccion muestra, a principios de 1995, un solo ejemplo de efecto a corto plazo entre reinyeccion y sismicidad (pero apoyandose en la localizacion con una red local), y posiblemente varios a mediano plazo (entre 6 y 8 meses). En este ultimo caso, el aumento de gasto correspondiente al inicio del invierno, se traduciria en uno o varios eventos de magnitud comprendida entre Ml=3 y Ml=4 a mediados del verano. Considerando el contexto tectonico del area, existe tambien la posibilidad que estos eventos esten asociados a la falla Cerro Prieto o al centro de dispersion responsable de la anomalia termica. El monitoreo continuo con una red local permitira precisar estos resultados preliminares, obtenidos con las redes regionales.

  3. Organic geochemistry of endoevaporitic environments: Microbial diversity and lipid biomarkers from gypsum deposits at the E.S.S.A Salt Works, Guerrero Negro, Baja, Mexico

    Science.gov (United States)

    Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Turk, K. A.; Kubo, M. D.

    2006-12-01

    We report lipid biomarker distributions and microbial diversity of endoevaporitic microbial communities from the gypsum crystallizer pond (Pond #9; ~170 % salinity) at the Exportadora de Sal, (ESSA) salt works in Guerrero Negro, Baja California Sur, Mexico. According to phylogenetic analysis using 16S rRNA sequences, gypsum crusts from this system host stratified communities of unicellular cyanobacteria (orange Euhalothece), filamentous cyanobacteria (green Oscillatoria), purple sulfur bacteria (Chromatium), and other halophilic microorganisms. Lipids collected from spatially discrete horizons of the crust indicate a shift in C16, C18 and C19 fatty acids from lower concentrations in the upper aerobic layers to higher concentrations in the deeper anaerobic zones of the crust. Compound specific isotopic analyses (CSIA) of fatty acids differentiate the more abundant C16, C18 and C19 homologues as isotopically lighter (~ -20% to -25% δ13C VPDB) from C15, C17 and C20 homologues which are isotopically heavier (~ -14% to -19% δ13C VPDB) and occur in lower abundance. CSIA of multiple compound classes reveals that gypsum domain lipids have significantly lighter δ13C values than those of lipids from the laminated benthic microbial mats living at lower salinities (i.e. ~100% to 115% salinity) in the ESSA system. This isotopic effect is consistent with intensive internal nutrient cycling within the crust. Squalane/squalene were detected in extracts from the gypsum crust indicating the presence of archaea. Diploptene is the most abundant triterpenoid of the C28 C32 hopanoids. Branched alkanes with quaternary substituted carbons (BAQCs) were also detected. These compounds have been linked with sulfur oxidizing microbial activity, which is known to be a major respiratory process in the crust's internal O2 budget (Sørensen et al., 2004). Abundant organosulfur compounds (OSC) and thiacycloalkanes in extracts indicate a vigorous internal sulfur cycle that influences both

  4. A geochemical comparison of alkalic lavas in the Trans-Mexican Volcanic Belt, peninsular Baja California and intraplate volcanoes in the eastern Pacific

    Science.gov (United States)

    Tian, L.; Castillo, P. R.

    2011-12-01

    The Trans-Mexican Volcanic Belt (TMVB) is a continental volcanic arc built along the southern edge of the North American plate. The volcanic rocks along TMVB are compositionally diverse and the origin of its alkalic lavas with ocean island basalt (OIB)-like composition is highly controversial. Alkalic lavas from four regions in the western, central, and eastern TMVB [e.g., Verma and Hasenaka, Geochem. J., 58, 2004; Petrone et al., Geol. S. Am. S., 402, 2006; Orozco-Esquivel et al., Geol. Soc. Amer. Bull., 93, 2007] are compared with similar OIB-like alkalic lavas from peninsular Baja California [e.g., Storey et al., Terra Nova, 1, 1989; Castillo, Geol. Soc. Amer. Bull., 120, 2008] and intraplate volcanoes in the eastern Pacific [Tian et al., Geochem. Geophys. Geosyst., 12, 2011] in order to ascertain their geochemical similarities and differences and to constrain the compositions of their respective magma sources. A few of the alkalic lavas from TMVB have very similar trace element and isotopic compositions as the OIB-like alkalic lavas from peninsular Baja California and intraplate volcanoes in the eastern Pacific. Majority of the TMVB alkalic lavas, however, are compositionally more heterogeneous, similar to the less-alkalic Nb-enriched basalts in peninsular Baja California representing OIB-like alkalic lavas that had been contaminated by other mantle components and/or crustal materials. Thus, data seem to indicate that all the OIB-like alkalic lavas can be traced to a similar source, the compositionally heterogeneous Pacific asthenosphere.

  5. Organizaciones no gubernamentales y la contaminación del aire en la frontera de Baja California, México-California, Estados Unidos. Contexto y desafíos

    OpenAIRE

    José María Ramos; Marcela Reyes

    2006-01-01

    Aquí se analiza el papel de las principales organizaciones no gubernamentales (ONG) ambientalistas, con respecto a la contaminación del aire en la frontera de Mexicali, Baja California (BC), México y Valle Imperial, California en Estados Unidos (EEUU). Los temas principales son los antecedentes de la polución del aire en la zona mencionada; el papel de las ONG, la gestión asociada y el marco institucional y legal de la participación ciudadana, ...

  6. Evaluación genética de un hato holstein en Baja California Sur, utilizando un modelo animal con mediciones repetidas

    OpenAIRE

    Alejandro Palacios Espinosa; Felipe Rodríguez Almeida; Jorge Jiménez Castro; José Luis Espinoza Villavicencio; Rafael Núñez Domínguez

    2001-01-01

    Se utilizaron datos de 2618 registros de producción de leche (de 1991 a 1998) y ajustados a 305 días, para estimar la producción de leche promedio y predecir los valores de cría en un hato Holstein ubicado en Baja California Sur, México. Dichos datos son importantes para la selección de los futuros reproductores, por lo que se efectuó una evaluación genética mediante un modelo animal con mediciones repetidas, que incluyó los efectos aleatorios genéticos aditivos de los animales, un efecto ale...

  7. Ictiofauna de la laguna de San Ignacio, Baja California Sur, México: nuevos registros y ampliaciones de ámbito

    OpenAIRE

    1998-01-01

    Se actualiza el inventario ictiológico de la Laguna de San Ignacio, Baja California Sur (México), con la adición de 26 especies. Se registra la ampliación de distribución geográfica de ocho especies. En la lista sistemática se aportan datos acerca de las tallas, números de registro en la colección, cantidad de especímenes recolectados y su afinidad ictiogeográfica. La lista actualizada incluye 107 especies, 89 géneros, 54 familias y 21 órdenes.

  8. Riqueza ecológica y pobreza económica en un área natural protegida en Baja California Sur

    OpenAIRE

    Elizabeth Olmos-Martínez; Silvia Salas; Luis Felipe Beltrán-Morales; Aurora Breceda-Solís; Alfredo Ortega-Rubio

    2008-01-01

    Aquí se aborda el concepto de pobreza, enmarcado en el contexto de un área natural protegida (ANP), con la metodología propuesta por la Secretaría de Desarrollo Social (SEDESOL), cuya política pública maneja tres categorías para medirla: pobreza alimentaria, pobreza de capacidades y pobreza de patrimonio. El estudio de caso se efectuó en el ejido San Jorge (ESJ), ubicado dentro de la Reserva de la Biosfera Sierra La Laguna (REBISLA), en Baja California Sur. El anál...

  9. Estatus actual de conservación de seis especies de peces dulceacuícolas de la península de Baja California, México

    OpenAIRE

    Gorgonio Ruiz-Campos; Faustino Camarena-Rosales; Adrián F. González-Acosta; Alejandro M. Maeda-Martínez; García de León, Francisco J.; Alejandro Varela-Romero; Asunción Andreu-Soler

    2014-01-01

    Se determinó el estatus actual de conservación de 6 peces dulceacuícolas nativos de la península de Baja California ( Entosphenus tridentatus , Oncorhynchus mykiss nelsoni , Fundulus lima , Cyprinodon macularius , Gasterosteus aculeatus y Gobiesox juniperoserrai ), incluidos en la Norma Oficial Mexicana 059-2010, a partir de la información obtenida durante el periodo 2000-2014. Con excepción de E. tridentatus en la cuenca del río Santo Domingo y de G. juniperoserrai en la cuenca de Las Pocita...

  10. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico

    Science.gov (United States)

    Des Marais, D. J.; Stallard, M. L.; Nehring, N. L.; Truesdell, A. H.

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  11. Air quality and its integration within urban planning: Mexicali, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Elva Alicia Corona–Zambrano

    2009-07-01

    Full Text Available As a result of world wide urbanization and industrialization, urban air pollution shows a growing trend directly proportional to increasing demands on energy for domestic and industrial activities. From this point of view, cities along with their urban, functional and morphological structure are not being planned with pollution prevention or minimum environmental impacts in mind. This work has two purposes: first, it sets an assessment of air quality in Mexicali by analyzing O3, CO, SO2, NO2 and PM10 emissions in relation to urban structure. And second, the assessment of already implemented urban strategies aimed to minimize environmental impacts. This work also presents a scheme that incorporates air quality issues into town planning and urban management.

  12. Antimony in the Contaminated Site of El Triunfo, Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Marmolejo-Rodríguez A. J.

    2013-04-01

    Full Text Available Antimony has properties similar to arsenic with some of its compounds toxic to humans. Therefore it is necessary to control the wastes accumulated by anthropogenic activities, such as mining, where it is in tailings to be released to the environment. According to the Environment Protection Agency, the maximum value in sediments is 11.2 mg Sb kg–1 and the Earth’s crust average is 0.2 mg Sb kg–1. In this semiarid area, the drainage basin El Carrizal is impacted with wastes of an abandoned gold mine at the Mining District El Triunfo (MD – ET which have tailings with 17,600 mg kg–1 of antimony. In the main dry river (arroyo, the Sb content is between 0.6 and 122 mg kg–1. This element is transported from the source throughout the fluvial basin to discharge into the Pacific Ocean. In the arroyo mouth we collected one sedimentary core and the sediment from dunes (28.6 – 45.7 and 6.43 – 7.74 mg Sb kg–1. This research concluded the antimony is enriched in this semiarid system, with Normalized Enrichment Factors severely enriched mainly in arroyo sediments close to the MD-ET

  13. Use of digital multispectral videography to assess seagrass distribution in San Quintin Bay, Baja California, Mexico

    Science.gov (United States)

    Ward, D.H.; Tibbitts, T.L.; Morton, Alexandra; Carrera-Gonzalez, Eduardo; Kempka, R.

    2004-01-01

    Apparent threats to the spatial distribution of seagrass in San Quinti??n Bay prompted us to make a detailed assessment of habitats in the bay. Six coastal habitats and three seagrass subclasses were delineated using airborne digital multispectral videography (DMSV), Eelgrass, Zostera marina, was the predominant seagrass and covered 40% (1949 ha) of the areal extent of the bay in 1999. Eelgrass grew over a wide range of tidal depths from about -3.0 in mean lower low water (MLLW) to about 1.0 m MLLW, but greatest spatial extent occurred in intertidal areas -0.6 m to 1.0 m MLLW. Exposed-continuous (i.e., high density) eelgrass was the most abundant habitat in the bay. Widgeongrass, Ruppia maritima, was the only other seagrass present and covered 3% (136 ha) of the areal extent of the entire bay. Widgeongrass grew in single species stands in the upper intertidal (??? 0.4 MLLW) and intermixed with eelgrass at lower tidal depths. Overall accuracy of the six habitat classes and three subclasses in the DMSV map was relatively high at 84%. Our detailed map of San Quintin Bay can be used in future change detection analyses to monitor the health of seagrasses in the bay.

  14. Lung cell toxicity experimentally induced by a mixed dust from Mexicali, Baja California, Mexico.

    Science.gov (United States)

    Osornio-Vargas, A R; Hernández-Rodríguez, N A; Yáñez-Buruel, A G; Ussler, W; Overby, L H; Brody, A R

    1991-10-01

    Lung disease caused by nonoccupational exposures to inorganic particles from the soil has been reported in several areas of the world. We tested the toxic potential of dust samples from a Mexican city (Mexicali) that is frequently affected by dust storms and is geographically related to the area of San Diego, CA, where constituents of the soil have been reported to be fibrogenic. We found that samples of Mexicali dust are a mixture of approximately 75% potassium aluminum silicates (illite) and approximately 20% silica. Respirable size particles were highly hemolytic and induced lactic dehydrogenase release from alveolar macrophages exposed in vitro. Animals instilled intratracheally with the dust developed a multifocal interstitial lung disease associated with deposits of the aluminum silicates, which were identified by X-ray microanalysis. Inhalation studies in rats demonstrated that the majority of particles were deposited preferentially at the first alveolar duct bifurcations. Twenty-four hours later, numerous particles had been ingested by alveolar macrophages that had migrated to those sites of deposition. It is proposed that alveolar macrophages are attracted to the deposited particles by complement fragments since Mexicali dust is capable of activating complement proteins from both serum and bronchoalveolar lavage. Activation resulted in alveolar macrophage chemotaxis. Mexicali dust induced biological activities and lung changes similar to those of asbestos and silica, suggesting that this material could be an etiologic agent of pulmonary fibrosis in exposed individuals.

  15. Geophysical Exploration of Faults, Fissures, and Fractures at Four Sites in Mexicali, Baja California, Mexico

    Science.gov (United States)

    Lázaro-Mancilla, O.; Gonzalez-Fernandez, A.; Contreras-Corvera, A.; Stock, J. M.; Moreno-Ayala, D.; Ramirez-Hernandez, J.; Carreon-Diazconti, C.; Lopez, D. A. L.; Lopez, J. R.

    2014-12-01

    We conducted field geophysical measurements in areas in the City of Mexicali that are associated with geological faults, fissures, and fractures. The study sites are: 1) Instituto Tecnologico de Mexicali 2) The buried trace of the Michoacan de Ocampo fault in the urban zone 3) Rio Nuevo 4) A site reported by Frez (2013) with ground rupture SW of Cerro Prieto At Site 1, seismic reflection profiling used a cable with 24 geophones at 1 m spacing. The source was a 3.6 kg sledge hammer, with 3 impacts per shot point. 347 shot points at 2 m spacing provided 6 fold coverage along a straight line with minimal elevation changes. Sample rate was 2000/s, and record length 1 s; reflections were seen down to 0.3 s TWTT. Processing included: frequency filter, fk filter, predictive deconvolution, geometry, velocity analysis, NMO and stacking. Lateral changes in the seismic section are due to surface modification and/or the presence of faults.At site 2, we measured 222Radon in 36 locations along 17 profiles across the fault, using inherent alpha spectrometry with a Durridge RAD7 detector. Each site was measured at a depth of 60 cm, with 31 five-minute readings in a 3 hour period, interspersed with 10 minute of background purge and 3 five-minute background measurements. In a profile parallel to the fault, 78% of the readings were > 100 pCi/L, confirming the presence of the fault along the swath surveyed. At Site 3 we compiled observations of post-earthquake cracks, conducted reconnaissance, and measured some profiles using 100 MHz GPR. These observations showed that the cracks are associated with ground failure due to earthquake shaking. At Site 4 our new 222Radon gas measurements complemented a pre-existing profile that had high 222Radon values lacking a structural explanation. Related to this we found that this region has two NW-SE trending features: a magnetic anomaly low of 360 nT (Evans, Summer and Castillo, 1972) and a graben reported by the Mexican Geological Survey in 2003. Earthquake patterns and seismic studies in a wider area north of the border indicate a possible buried fault a few km west of the Imperial fault, as well as short NE-striking faults controlling basement structure. These results highlight some very useful methods for finding fault traces in a flat region covered with agricultural fields or disturbed by anthropogenic activity.

  16. Risk factors for brucellosis seropositivity of goat herds in the Mexicali Valley of Baja California, Mexico.

    Science.gov (United States)

    Mikolon, A B; Gardner, I A; Hernandez De Anda, J; Hietala, S K

    1998-12-01

    A case-control study was conducted in the Mexicali Valley to identify risk factors for goat-herd seropositivity for Brucella melitensis. Nineteen case herds (> or = 2 positive results with the 8% rose bengal plate test (RBT)) and 55 control herds (zero positive results in RBT), matched for herdsize and geographic location, were enrolled. Conditional logistic regression was used to construct a multivariable model of the odds of seropositivity using variables assessed in a questionnaire administered to goat ranchers. The final model for herd seropositivity included increased risk from importation of goats from other Mexican states, the presence of La Mancha breed does, and the presence of does born outside the herd. Increasing herdsize was also highly significant (p < 0.01). In addition, a significant (p < 0.05) positive association was found between the presence of seropositive dogs (as assessed by RBT) and seropositive goats on the same ranch.

  17. Proceedings: third symposium on the Cerro Prieto geothermal field, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    These proceedings include both English and Spanish versions of each paper presented at the symposium. Illustrations and tables, which have been placed between the two versions, include captions in both languages. Forty-one papers are included. Five papers were indexed for EDB previously. Separate abstracts were prepared for thirty-three papers and three were listed by title.

  18. Shallow Miocene basaltic magma reservoirs in the Bahia de Los Angeles basin, Baja California, Mexico

    Science.gov (United States)

    Delgado-Argote, Luis A.; García-Abdeslem, Juan

    1999-01-01

    The basement in the Bahı´a de Los Angeles basin consists of Paleozoic metamorphic rocks and Cretaceous granitoids. The Neogene stratigraphy overlying the basement is formed, from the base to the top, by andesitic lava flows and plugs, sandstone and conglomeratic horizons, and Miocene pyroclastic flow units and basaltic flows. Basaltic dikes also intrude the whole section. To further define its structure, a detailed gravimetric survey was conducted across the basin about 1 km north of the Sierra Las Flores. In spite of the rough and lineal topography along the foothills of the Sierra La Libertad, we found no evidence for large-scale faulting. Gravity data indicates that the basin has a maximum depth of 120 m in the Valle Las Tinajas and averages 75 m along the gravimetric profile. High density bodies below the northern part of the Sierra Las Flores and Valle Las Tinajas are interpreted to be part of basaltic dikes. The intrusive body located north of the Sierra Las Flores is 2.5 km wide and its top is about 500 m deep. The lava flows of the top of the Sierra Las Flores, together with the distribution of basaltic activity north of this sierra, suggests that this intrusive body continues for 20 km along a NNW-trending strike. Between the sierras Las Flores and Las Animas, a 0.5-km-wide, 300-m-thick intrusive body is interpreted at a depth of about 100 m. This dike could be part of the basaltic activity of the Cerro Las Tinajas and the small mounds along the foothills of western Sierra Las Animas. The observed local normal faulting in the basin is inferred to be mostly associated with the emplacement of the shallow magma reservoirs below Las Flores and Las Tinajas.

  19. Model for the heat source of the Cerro Prieto magma-hydrothermal system, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Bird, D.K.; Williams, A.E.; Schiffman, P.; Cox, B.

    1981-01-01

    Earlier studies at Cerro Prieto led to the development of a qualitative model for fluid flow in the geothermal system before it was drilled and perturbed by production. Current efforts are directed towards numerical modeling of heat and mass transfer in the system in this undisturbed state. This one-dimensional model assumes that the heat source was a single basalt/gabbro intrusion which provided heat to the system as it cooled. After compilation of various information of the physical properties of the reservoir, the enthalpy contained in two 1 cm thick sections across the reservoir orthogonal to each other was calculated. Various shapes, sizes and depths for the intrusion were considered as initial conditions and boundary conditions for the calculations of heat transfer. A family of numerical models which so far gives the best matches to the conditions observed in the field today have in common a funnel-shaped intrusion with a top 4 km wide emplaced at a depth of 5 km some 30,000 to 50,000 years ago, providing heat to the geothermal system.

  20. Hydrothermal flow regime and magmatic heat source of the Cerro Prieto geothermal system, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Bird, D.K.; Schiffman, P.; Williams, A.E.

    1984-01-01

    This detailed three-dimensional model of the natural flow regime of the Cerro Prieto geothermal field, before steam production began, is based on patterns of hydrothermal mineral zones and light stable isotopic ratios observed in rock samples from more than 50 deep wells, together with temperature gradients, wireline logs and other data. At the level so far penetrated by drilling, this hydrothermal system was heated by a thermal plume of water close to boiling, inclined at 45/sup 0/, rising from the northeast and discharging to the west. To the east a zone of cold water recharge overlies the inclined thermal plume. Fission track annealing studies show the reservoir reached 170/sup 0/C only 10/sup 4/ years ago. Oxygen isotope exchange data indicate that a 12 km/sup 3/ volume of rock subsequently reacted with three times its volume of water hotter than 200/sup 0/C. Averaged over the duration of the heating event this would require a flow velocity through a typical cross-section of the reservoir of about 6 m/year. The heat in storage in that part of the reservoir hotter than 200/sup 0/C and shallower than 3 km depth is equivalent to that which would be released by the cooling of about 1 or 2 km/sup 3/ of basalt or gabbro magma.

  1. Model of the heat source of the Cerro Prieto magma-hydrothermal system, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Bird, D.K.; Williams, A.E.; Schiffman, P.; Cox, B.

    1982-08-10

    Earlier studies at Cerro Prieto by UCR have led to the development of a qualitative model for field flow in the geothermal system before it was drilled and perturbed by production. Current efforts are directed towards numerical modelling of heat and mass transfer in the system in this undisturbed state. A two-dimensional model assumes that the heat sources were a single basalt/gabbro intrusion which provided heat to the system as it cooled. After compiling various information on the physical properties of the reservoir, the enthalpy contained in two 1cm thick section across the reservoir orthogonal to each other was calculated. Next various shapes, sizes and depths for the intrusion as initial conditions and boundary conditions for the calculation of heat transfer were considered. A family of numerical models which so far gives the best matches to the conditions observed in the field today have in common a funnel-shaped intrusion with a top 4km wide emplaced at a depth of 5km some 30,000 to 50,000 years ago, providing heat to the geothermal system. Numerical modelling is still in progress. Although none of the models so far computed may be a perfect match for the thermal history of the reservoir, they all indicate that the intrusive heat source is young, close and large.

  2. Aseismic Slip Observed on the Faults in Mexicali Valley, Baja California, Mexico.

    Science.gov (United States)

    Glowacka, E.; Sarychikhina, O.; Suarez, F.; Nava, F.; Farfan, F.; Cossio Battani, G. D.; Guzman, M.

    2007-05-01

    The Mexicali Valley, which is part of the Salton Trough, is located within an active tectonic region, in the boundary between the Pacific and North American plates; a region featuring a wide zone of transform faults associated with San Andreas fault system, and a zone of distributed deformation in the pull-apart center of Cerro Prieto. Since 1996, geotechnical instruments have operated in the Valley, for continuous recording of deformation phenomena. To date, the network includes three crackmeters, eight tiltmeters, and seven piezometers installed in the shallow aquifer; all instruments have sampling intervals in the 1 to 20 minutes range. The mainly vertical displacement at Saltillo fault (known before as southernmost part of Imperial fault) has been measured on a continuous basis since February 1996 by a crackmeter installed in Ejido Saltillo (Glowacka 1996; Nava and Glowacka, 1999). In 1998 a tiltmeter was installed on the fault and a second crackmeter , in a horizontal direction, about 60° from the fault strike, was installed about 1 km south of ES. Another crackmeter in the vertical plane crossing Morelia fault and a 3D Witness on the Cerro Prieto fault were installed in 2004. In 2003 seven digital water level meters were installed at depths up to 500 meters in the local piezometric wells, with the purpose of recording aquifer level changes. The observed deformation rates measured on the Saltillo fault are 6 cm/yr and 2 cm/yr for the vertical and horizontal components, respectively and occurs in steps (creep events), separated by months of quiescence, and large events account for 70 percent of the vertical displacement. Aseismic creep events have amplitudes of 1-3 cm and durations of 1-3 days. Much less precise measurements from the Cerro Prieto fault show vertical deformation on the fault with velocity around 3.1 cm/yr , and the rate does not depend on the local seismicity. Horizontal rates change slightly with the presence of seismicity when very small right lateral deformation (few mm/yr) can be observed. From the delay measured on different instruments installed on the Saltillo fault one can conclude that creep events have an apparent migration velocity of the order of 4 cm/s. Comparison between occurrence of creep events and the water level record done for the piezometer installed nearby, shows that in four cases a water level anomaly is associated with a creep event. We discuss some possible relation between creep phenomenon and water level changes, and tectonics, geology and anthropogenic activity in the Mexicali Valley. This research is sponsored partly by the CONACYT project 45997-F.

  3. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico.

    Science.gov (United States)

    Des Marais, D J; Stallard, M L; Nehring, N L; Truesdell, A H

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  4. The lambeosaurine dinosaur Magnapaulia laticaudus from the late cretaceous of Baja California, Northwestern Mexico.

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    Albert Prieto-Márquez

    Full Text Available The taxonomy, osteology, phylogenetic position, and historical biogeography of the lambeosaurine hadrosaurid Magnapaulia laticaudus (new combination are revised. The diagnosis of this species is amended on the basis on two autapomorphies (i.e., longest haemal arches of proximal caudal vertebrae being at least four times longer than the height of their respective centra; base of prezygapophyses in caudal vertebrae merging to form a bowl-shaped surface and a unique combination of characters (i.e., downturned cranioventral process of the maxilla; tear-shaped external naris with length/width ratio between 1.85 and 2.85; neural spines of dorsal, sacral, and proximal caudal vertebrae being at least four times the height of their respective centra. A maximum parsimony analysis supports a sister taxon relationship between M. laticaudus and Velafrons coahuilensis. Both taxa constitute a clade of southern North American lambeosaurines, which forms a sister relationship with the diverse clade of helmet-crested lambeosaurines from northern North America that includes well-known genera like Corythosaurus, Lambeosaurus, and Hypacrosaurus. According to the results of a Dispersal-Vicariance analysis, southern North American lambeosaurines split from the northern forms via vicariance from a common ancestor that lived in both the northern and southern regions of the continent.

  5. Frecuencias de grupos sanguíneos e incompatibilidades ABO y RhD, en La Paz, Baja California Sur, México

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    del Peón-Hidalgo Lorenzo

    2002-01-01

    Full Text Available Objetivo. Determinar las frecuencias génicas y de fenotipo, y predecir el riesgo de incompatibilidad y aloinmunización materna en la población de La Paz, Baja California Sur, México. Material y métodos. Estudio descriptivo en el que se evaluaron 1 809 disponentes sanguíneos altruistas que acudieron en 1998 al Hospital General de Zona, del Instituto Mexicano del Seguro Social en La Paz, Baja California Sur, México, tipificados por aglutinación en tubo. Las frecuencias génicas fueron estimadas asumiendo condiciones de equilibrio, y las incompatibilidades y riesgo de aloinmunización de acuerdo con la literatura. Los datos fueron evaluados estadísticamente mediante ji². Resultados. La población reveló las siguientes frecuencias en porcentaje: O, 58.49; A, 31.40; B, 8.40; AB, 1.71; RhD, 95.36; y RhD negativo, 4.64 y las frecuencias génicas fueron i, 0.7648; I A, 0.1821; I B, 0.0519; D, 0.7845; d, 0.2155, respectivamente. Las incompatibilidades en parejas y maternofetal fueron 0.3023 y 0.1685 para ABO, 0.0442 y 0.0364 para RhD y 0.0134 y 0.0061 para incompatibilidad doble, respectivamente. La probabilidad de aloinmunización materna fue estimada en 0.0309. Conclusiones. En La Paz, los grupos O y RhD son los más abundantes, aunque las frecuencias están entre las más bajas en México, contrario a lo ocurrido para A y RhD negativo. La probabilidad de aloinmunización materna y las incompatibilidades son también elevadas. Los grupos ancestrales blanco, negro e indio interactuaron en la zona noroeste del país, determinando al migrar a Baja California Sur un mestizaje probablemente similar al resto de la zona noroeste.

  6. La dinámica territorial de las principales instituciones bancarias en la península de Baja California: estructura e interrelaciones

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    Lilia Susana Padilla y Sotelo

    2001-01-01

    Full Text Available Este trabajo muestra la distribución territorial de las principales instituciones bancarias en el espacio urbano de la península de Baja California Se inicia con los antecedentes de la organización de la banca de la zona y su relación en el contexto nacional en donde destaca su localización fronteriza. El análisis locacional a través del examen de distribución territorial de las 158 sucursales bancarias de las siete principales instituciones permite detectar una sustancial en concentración en comunidades urbanas de la porción norte, tanto en pequeñas como en medias, y una marcada tendencia a ubicarse en localidades de rango poblacional con comportamientos diferenciados, aspecto que se relaciona con la actividad económica que se realiza en las mismas, lo que las convierte en espacios preferenciales, resultado de desequilibrios territoriales. Sobresalen las ciudades de Tijuana y Mexicali y, en menor proporción, las de La Paz y Ensenada. La distribución territorial de las instituciones bancarias en la península de Baja California sigue el mismo patrón de comportamiento que el de la escala nacional, el de ubicación, de acuerdo con la especialidad.

  7. Diálogo de saberes ambientales entre Europa-América. Agroecosistemas oasianos en Baja California Sur s. XVIII-XX

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    Ortega Santos, Antonio

    2015-06-01

    Full Text Available During two centuries, Oasis Communities of Baja California had been living in a intense connection with their environment. With the arrival of Jesuits, a deep extermination of biocultural heritage and socioenvironmental knowledges of these communities, repopulating of vegetable garden and drylands with people –in many cases, settler from the south of Spain- reconstructing the territorial identity as ranchera to manage the ecosystems under pattern of self-competence and under-consumption, due to the strong environmental constraints of lower california agro-ecosystem. At the beginning of XXIth century, Oasis Communities are fighting against the loss of community heritage, embedded in Eden with enormous bio-cultural dimension, rescuing and keeping crops from Europe with the Jesuits arrival. This frame allow us to draw a colonization process of ecosystems during contemporary age.Desde hace más de dos siglos, las Comunidades Oasianas de Baja California Sur han estado viviendo en íntima conexión con su medio ambiente. Con la llegada de los Jesuitas se produjo un intenso proceso de exterminio biocultural de los saberes sociambientales de esas comunidades, repoblando estas huertas y llanos con población -en muchos casos colonos- procedentes del sur de España-, redimensionado la identidad territorial como ranchera que gestionó los ecosistemas bajo pautas de autosuficiencia y subconsumo, dadas las fuertes constricciones socioambientales de agroecosistemas sudcalifornianos. A inicios del siglo XXI, las comunidades oasianas luchan contra la pérdida de sus saberes comunitarios, enclavados en edenes de enorme potencial biocultural, rescatando y manteniendo los cultivos traídos con la llegada de los jesuitas. Este marco nos permite describir un proceso de colonización de los ecosistemas a lo largo de los dos últimos siglos.

  8. Arsenic and mercury contamination of sediments of geothermal springs, mangrove lagoon and the Santispac bight, Bahía Concepción, Baja California peninsula.

    Science.gov (United States)

    Leal-Acosta, María Luisa; Shumilin, Evgueni; Mirlean, Nicolai; Sapozhnikov, Dmitry; Gordeev, Vyacheslav

    2010-12-01

    In order to find out the environmental impact on the coastal zone, the composition of sediments of the intertidal geothermal hot spring zone and adjacent area of Playa Santispac in the pristine Bahía Concepción (Baja California peninsula) was studied. High concentrations of As (13-111 mg kg⁻¹) and Hg (0.55-25.2 mg kg⁻¹) were found in the sediments of the geothermal sources. Arsenic and Hg concentrations decrease rapidly in the adjacent small mangrove lagoon sediments and reach background levels (0.7-2.6 mg kg⁻¹ and 6-60 μg kg⁻¹ respectively) in the marine sediments collected in front of Playa Santispac.

  9. Reconnaissance field report for the search of large telescope sites in the sierra San Pedro Mártir, Baja California, México

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    Erika Sohn

    2007-01-01

    Full Text Available La Sierra San Pedro Mártir en el estado de Baja California, México, es conocida por sus excelentes condiciones para la observación astronómica. Ofrece una serie de sitios con elevaciones que rebasan los 2650 m, potencialmente apropiados para la instalación de futuros grandes telescopios. Algunos de estos sitios son remotos y es necesario determinar sus rutas de acceso para efectuar mediciones de evaluación de las condiciones para la observación astronómica. Durante el verano de 2005 se visitaron seis sitios que pueden ser adecuados para la instalación de telescopios e instrumentos de medición de la calidad del cielo, para determinar sus coordenadas asÍ como sus posibles rutas de acceso. En este trabajo se presenta una breve descripción de cada uno de estos sitios

  10. El corredor turístico Loreto-Nopoló- Puerto Escondido, Baja California sur, en el contexto de los centros integralmente planeados

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    Rosa Alejandrina De Sicilia Muñoz

    2000-01-01

    Full Text Available El presente trabajo muestra la situación actual del corredor turístico Loreto-Nopoló- Puerto Escondido, Baja California Sur, México. Este Corredor es uno de los cinco Centros Integralmente Planeados (CIP que ideara el Fondo Nacional de apoyo al Turismo, dependiente del gobierno mexicano, en los años setenta. Se presenta una breve reseña histórica de la evolución del turismo en este lugar, su designación como CIP, y se examinan algunas razones por las que este centro no ha tenido el desarrollo que se esperó en un principio.

  11. Emprendimientos de micro y pequeñas empresas mexicanas en un escenario local de crisis económica: El caso de Baja California, 2008-2011

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    Alejandro MUNGARAY LAGARDA

    2015-01-01

    Full Text Available En este trabajo se analiza la aplicación de una política pública regional que favorece el desa - rrollo de las micro y pequeñas empresas en la economía de Baja California para compensar l a generación de empleo. Mediante los modelos de regresión estimados, se encuentra que en un escenario de crisis económica global donde la producción y el empleo en la gran empresa se restringen y el trabajador es sustituido por procesos más tecnif i cados, la proliferación de micros y pequeñas empresas son un mecanismo compensatorio para minimizar los efectos del desempleo.

  12. El papel de los comités Pro-Estado en la creación del estado de Baja California

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    Lawrence Douglas Taylor

    1999-01-01

    Full Text Available El artículo trata del papel de los Comités Pro-Estado en la formación de Baja California como estado. Se analizan las raíces de la autonomía política en la península, que se remontan al Porfiriato, así como el impacto de la Revolución Mexicana sobre este proceso. Se examinan los diversos movimientos pro- estado que surgieron de 1929 en adelante la composición de sus grupos de integrantes, sus objetivos y contribuciones principales en términos de dirigir el sentimiento popular hacia la realización de esta meta.

  13. La micro y pequeña empresa como generadora de empleo en Baja California durante la crisis de 2008-2009

    OpenAIRE

    Alejandro Mungaray Lagarda; José Gabriel Aguilar Barceló; Natanael Ramírez Angulo; Astrid Ortiz Figueroa

    2016-01-01

    El objetivo del trabajo ha sido evaluar la importancia de la conformación del tejido empresarial en la evolución de la actividad económica y la generación de empleo en Baja California en el entorno de la crisis global de 2008-2009, con énfasis en el comportamiento de la micro y pequeña empresa. Lo anterior se consigue a través de la metodología de un análisis de correspondencias de carácter exploratorio y otro econométrico con fines confirmatorios en los cuales se utilizaron variables de los ...

  14. Riqueza específica de copépodos en Bahía Magdalena, Baja California Sur, México

    OpenAIRE

    2004-01-01

    Con el fin de estimar la riqueza específica de copépodos en Bahía Magdalena, Baja California Sur, México, se analizaron muestras obtenidas en distintos años y con diferentes artes de recolecta de zooplancton. Esta información se complementó con el análisis bibliográfico, obteniéndose un total de 152 especies de copépodos pelágicos, epibénticos y parásitos, que habitan en aguas de la bahía. Las especies encontradas pertenecen a los órdenes Calanoida, Monstrilloida, Siphonos-tomatoida y Poecilo...

  15. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in July 2010

    Science.gov (United States)

    2011-04-01

    although the inshore/offshore disparity was markedly less along Line 60. Both these results may reflect stronger ekman transport-driven offshore...Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn University of California Santa Barbara, CA Paul Choboter CalPoly State

  16. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in June 2007

    Science.gov (United States)

    2007-10-01

    Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn University of California Santa Barbara, CA Paul Choboter CalPoly...State University San Luis Obispo, CA Roger Hewitt NOAA La Jolla, CA Carmen G. Castro Consejo Superior de Investigaciones Científicas Spain

  17. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in June 2008

    Science.gov (United States)

    2008-12-01

    Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn University of California Santa Barbara, CA Paul Choboter CalPoly State...University San Luis Obispo, CA Roger Hewitt NOAA La Jolla, CA Carmen G. Castro Consejo Superior de Investigaciones Científicas Spain

  18. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in October 2008

    Science.gov (United States)

    2009-05-01

    Reginaldo Durazo Universidad Autonoma de Baja California Ensenada, Mexico Libe Washburn University of California Santa Barbara, CA Paul Choboter...CalPoly State University San Luis Obispo, CA Roger Hewitt NOAA La Jolla, CA Carmen G. Castro Consejo Superior de Investigaciones

  19. Valoración socioambiental de los recursos naturales: el caso de los recursos minerales en la parte central de Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Luis F. Beltrán Morales

    2005-01-01

    Full Text Available Se seleccionaron 15 localidades ubicadas en el radio de influencia de dos depósitos evaluados de fosfato, esto con la finalidad de aplicar el método de valoración contingente del recurso y su medio ambiente: el depósito de Tembabichi en el margen del Golfo de California y el depósito de Santo Domingo en la costa del Pacífico en Baja California Sur, México. Se encontró una disposición media a pagar por los habitantes del área de estudio de $29.77 pesos mensuales para colaborar con el medio ambiente de su región. Hipotéticamente se daría una valoración contingente en el total del área de estudio de $227 859.58 pesos mensuales, es decir, $2 734 314.9 pesos anuales. Es una cantidad considerable de recursos para contribuir a mejoras en el medio ambiente por comunidades rurales con signos de marginación socioeconómica.

  20. Capacidades institucionales y desempeño de los organismos operadores de agua en Hermosillo, Sonora, y Mexicali, Baja California

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    Edmundo Loera Burnes

    2017-01-01

    Full Text Available Con el enfoque de capacidad institucional, aquí se analizan los factores políticos que influyeron en la asignación de recursos jurídicos, organizacionales y humanos para la Comisión Estatal de Servicios Públicos de Mexicali y para Agua de Hermosillo. También cómo influye el titular del Ejecutivo en su operación, y cómo se refleja la influencia de los factores institucionales en su desempeño. Si bien el estudio muestra la baja capacidad de ambos organismos en el aspecto de recursos humanos, el de Mexicali es superior en los otros rubros, y eso se traduce en más planeación y, por lo tanto, en mejor desempeño.

  1. Health Services Provision for Migrants Repatriated through Tijuana, Baja California: Inter-agency Cooperation and Response Capacity

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    YETZI ROSALES MARTÍNEZ

    2017-01-01

    Full Text Available este artículo explora la capacidad de respuesta institucional a las necesidades de salud de mi - grantes repatriados por t ijuana, Baja c alifornia, m éxico. s e realizaron 21 entrevistas semies - tructuradas a actores gubernamentales y de la sociedad civil. l a información fue analizada usando el concepto cooperación . se encontró la presencia de una red interinstitucional informal basada en objetivos comunes y una interdependencia de recursos. l a oferta de servicios de salud no es del todo funcional debido, en parte, a la ausencia de conf ianza entre algunos actores y a la saturación del más importante proveedor público de segundo y tercer nivel de atención en salud en t ijuana.

  2. Patógenos que afectan el cultivo de Litopenaeus vannamei en ambiente marino y dulceacuícola en el estado de Baja California, México - Pathogens that affect crop Litopenaeus vannamei in marine environment and freshwater in the state of Baja California, México

    Directory of Open Access Journals (Sweden)

    Jorge Cáceres Martínez

    2010-03-01

    discuten los resultados en sobrevivencia con la presencia de patógenos y epibiontes presentes. En general, se observó un patrón de incremento de epibiontes hacia el final del período de cultivo y una disminución en la concentración de oxígeno en el estanque, haciendo evidente el punto crítico al que se expone la producción, cuando se combinan epibiontes y condiciones ambientales. SummaryBetween April 2003 and September 2006 a study was carried out todetermine symbionts and pathogens in white shrimp, Litopenaeusvannamei, cultivated in seven different farms in the state of Baja California, Mexico; these farms used three different saline environments. The study included fresh tissue samples, histopathologic testing, and specific molecular tests for White Spot Syndrome Virus (WSSV. Colonies of the peritrichous protozoan Zoothamnium sp. were found attached to gills in shrimp grown in marine environments (with salinity of 35.9 ups with prevalence ranging from 0 to 80% and a severity range of 1to 2 (P=0-80%, GS=1-2, where the filamentous bacteria Leucothrix sp.(P=0-50%, GS=1-3 was also found. In cultured shrimps with groundwater (salinity of 1.6 ups, the epibionts associated to the gills were diatoms (P=0-20%, GS=1-2 and rotifers (P=0-40%, GS=1-2. And shrimps, whereriver-derived water was used (salinity ranging from 0.8 to 5.3 ups,colonial euglenoid algae (P=0-100% GS=1-2, peritrichous protozoaEpistylis sp. (P=0-100%, GS= 1-3 and filamentous bacteria Leucothrix sp. (P= 0-100, GS=1-3 were found, with branchials epibions. Histopathologic tests revealed melanosis, necrosis and hemocytic infiltration in gills, associated to epibionts and environmental conditions. Futhermore Cowdry type “A” inclusion bodies related to Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV, were also observed in shrimp of all of the farms studied (P= 2-36 % y GS=1-2. The histopathologic test performed on the shrimp hepatopancreas revealed the presence of bacterial infections (P=15

  3. The Link between Hi - Magnesium Andesite Distribution in Baja California Peninsula and the Undetached Fragments of the Farallon Plate

    Science.gov (United States)

    Wang, Y.; Forsyth, D. W.; Savage, B.

    2009-12-01

    About 12 Ma, the Guadalupe and Magdalena microplates ceased subducting beneath the North American continent, leaving behind plate fragments that became incorporated into the Pacific plate as spreading ceased. Spreading directions changed dramatically on Magdalena spreading centers, suggesting that the Farallon slab detached from the microplate fragments before or during the cessation of spreading. Although the sinking Farallon plate must have detached from those two microplates, it is not known where the detachments occurred and how much of the young slab was left behind still attached to the unsubducted surface microplates. We delineate the undetached Farallon fragments by looking for associated seismic velocity anomalies using teleseismic Rayleigh wave tomography and the stations of the USArray, NARS-Baja and RESBAN arrays. The lateral extent of the remanent plate fragments is indicated by a high (positive) velocity anomaly at 100 km depth (Figure 1). This landward edge of this anomaly coincides with the distribution of post-subduction high-Mg andesites (Bajaites, black region in Figure 1), which are inferred to involve fluid fluxed melting in overlying asthenospheric wedge and melting of the subducted oceanic crust. Shear velocity anomaly at 100 km

  4. Zonas costeras bajas en el Golfo de M\\'exico ante el incremento del nivel del mar

    CERN Document Server

    Carbajal-Dominguez, Adrian

    2011-01-01

    This paper presents an estimate of the land area affected in the event of sea level rise of 0.6 m, 1 m and 2 m for Mexican sates with coasts along Gulf of Mexico. Likewise, the number of residents in vulnerable areas that would occur in the scenario of sea level rise of 1 m is estimated. To do so, terrain elevation data of NASA's Shuttle Radar Topography Mission is used, along with a proprietary algorithm that allows the reconstruction of the affected area. In order to estimate the land area digital image processing is used. These results are geo-referenced for comparison with human settlements in the regions of interest. Results show that the total affected area corresponds to 1.26% of Mexico national territorial extension and 3.18% of the Mexico total population. 174 settlements with 1000 inhabitants or more are expected to be affected. The Mexican state with the largest area affected is Tabasco with more than 21% of its territory, while the most vulnerable population will be Veracruz, with more than 1 mill...

  5. 76 FR 34181 - Pistachios Grown in California, Arizona, and New Mexico; Proposed Amendments to Marketing Order

    Science.gov (United States)

    2011-06-13

    ... provide an additional tool to aid in the marketing of pistachios covered under the order. In the event the... Agricultural Marketing Service 7 CFR Part 983 Pistachios Grown in California, Arizona, and New Mexico; Proposed Amendments to Marketing Order AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed rule....

  6. 76 FR 60361 - Pistachios Grown in California, Arizona, and New Mexico; Decreased Assessment Rate

    Science.gov (United States)

    2011-09-29

    ... Internet at the address provided above. FOR FURTHER INFORMATION CONTACT: Andrea Ricci, Marketing Specialist... Agricultural Marketing Service 7 CFR Part 983 Pistachios Grown in California, Arizona, and New Mexico; Decreased Assessment Rate AGENCY: Agricultural Marketing Service, USDA. ACTION: Interim rule with...

  7. Records of Hippa strigillata (Stimpson, 1860 (Crustacea: Decapoda: Hippidae in the SE Gulf of California, Mexico

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    Daniela Ríos-Elósegui

    Full Text Available This paper presents details regarding the collections and records of H. strigillata in the Bay of Mazatlán, SE Gulf of California, Mexico. Samples of H. strigillata were obtained in this bay and suroundings area during different periods and deposited in the collection of UNAM, Mazatlán. Morphometric data, distribution, biological and ecological data were furnished.

  8. La descentralización: una mirada desde las políticas públicas y las relaciones intergubernamentales en Baja California

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    Martha Cecilia Jaramillo Cardona

    2010-01-01

    Full Text Available Otorgar autonomía política a los gobiernos no basta para asegurar o mejorar los servicios públicos, así lo muestra el análisis teórico de la presente investigación. Es necesario considerar la descentralización desde otros enfoques, porque sólo así se abren espacios para establecer relaciones francas, y tomar decisiones conjuntas entre Estado y sociedad para lograr las metas. Por tanto, el objetivo aquí es analizar la importancia del concepto descentralización y sus implicaciones, a partir de las políticas públicas y relaciones intergubernamentales. La descentralización constituye la oportunidad para que las administraciones locales diseñen políticas públicas acordes a las necesidades reales de sus regiones, y para que establezcan relaciones coordinadas entre los diversos ámbitos de gobierno. La investigación se realizó de 2003 a junio de 2006 en el estado de Baja California.

  9. El turismo alternativo: una opción para el desarrollo local en dos comunidades indígenas de Baja California

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    Nora L. Bringas R.

    2004-01-01

    Full Text Available Se analiza la relación entre desarrollo local, turismo alternativo y sustentabilidad. Nuestro punto de partida radica en la inquietud proveniente de dos de las comunidades indígenas de Baja California, México, la cual refiere a la exploración del turismo alternativo como una vía para el desarrollo. Aclaramos que los casos que analizamos no se refieren a una evaluación a posteriori del desarrollo de un proyecto de corte turístico. Más bien, este trabajo se enfoca en analizar la puesta en marcha de dicho proyecto: el surgimiento, la movilización y el involucramiento de nuevos actores con variados mecanismos de actuación y distintas capacidades, intereses y ámbitos de influencia. Esto nos permite ofrecer, a manera de contexto, algunos elementos necesarios para la estructuración de políticas para un turismo de corte alternativo enmarcadas en la sustentabilidad.

  10. Violencia laboral intramuros. Hostigamiento sexual y otras formas de violencia contra la mujer en las maquiladoras de Sonora y Baja California

    Directory of Open Access Journals (Sweden)

    Mireya Scarone Adarga

    2014-01-01

    Full Text Available El objetivo del presente artículo es identificar los comportamientos en torno al hostigamiento sexual y otras formas de violencia contra la mujer en el ámbito laboral de la maquiladora en los estados de Sonora y Baja California. Para analizar dichas conductas se requirió de herramientas de la metodología cualitativa, como las entrevistas semiestructuradas y grupos focales, que se les hicieron durante 2012 a 31 trabajadoras de maquiladoras de las entidades mencionadas. En los relatos se identificó la violencia psicológica, física, económica, sexual, verbal y simbólica. Se encontró una asociación entre expresiones de diversas formas de violencia laboral y el hostigamiento sexual con la organización del trabajo y la estructura laboral de la maquiladora, que es clave para comprender la subordinación y desvalorización del trabajo femenino en este sector.

  11. Results and evaluation of the first study of organochlorine contaminants (PCDDs, PCDFs, PCBs and DDTs), heavy metals and metalloids in birds from Baja California, México.

    Science.gov (United States)

    Jiménez, Begoña; Rodríguez-Estrella, Ricardo; Merino, Rubén; Gómez, Gema; Rivera, Laura; José González, María; Abad, Esteban; Rivera, Josep

    2005-01-01

    Organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p-p'-DDE), heavy metals (Pb, Cd, Zn, Cu), and arsenic were measured in house sparrows (Passer domesticus) and common ground doves (Columbina passerina) from Baja California Sur, México. Concentrations of PCDD/Fs were low, with 21 pg/g for house sparrows, and 7.7 pg/g for common ground doves. Non-ortho-PCB concentrations in house sparrow and common ground doves were 58 and 254 pg/g, respectively, and are within the highest concentrations reported in species that are in the low levels of food webs. The major differences in organochlorine levels between species were found for ortho-PCBs and DDTs. ortho-PCB levels were higher in the seedeater species, whereas DDT levels were higher in the omnivorous species. Heavy metal levels were far below those associated with negative effects.

  12. Un acercamiento a los actores ribereños en la pesca de camarón en San Felipe, Baja California

    Directory of Open Access Journals (Sweden)

    Virginia Guadalupe López Torres

    2016-01-01

    Full Text Available Desde hace varios años, los gobiernos nacionales y las instituciones internacionales han generado un conjunto de estrategias con el objetivo de disminuir los problemas ambientales, mediante la creación de reservas naturales. A pesar de ello, las acciones no consensuadas sobre la conser - vación no resuelven el deterioro ambiental, debido a que se debilita el tejido social necesario para impulsar un proceso de desarrollo comunitario sustentable; la conservación se trasforma en una actividad o interés ilegítimo para la población local, lo que endurece las posturas y dificulta la búsqueda conjunta de soluciones. Esto es lo que ha sucedido recientemente con los pescadores del puerto de San Felipe, Baja California, quienes en un par de ocasiones han cerrado la vía de comunicación terrestre entre Mexicali y el puerto, y se ha llegado al extremo de cerrar la garita internacional Mexicali-Calexico. Este malestar social, que amenaza con un mayor escalamiento, es el resultado de la negativa de los pescadores de San Felipe (y ahora también del Golfo de Santa Clara, en Sonora para modificar su arte de pesca, acorde con lo que plantea la nueva norma oficial mexicana.

  13. Disponibilidad y uso del agua en el oasis de los Comondú, Baja California Sur: retos y oportunidades para el desarrollo rural

    Directory of Open Access Journals (Sweden)

    Alba E. Gámez

    2014-01-01

    Full Text Available el desarrollo en las zonas áridas está estrechamente re - lacionado con la disponibilidad y calidad del recurso agua tanto para uso humano como productivo. Este artículo se refiere a su estado actual, disponibilidad y uso en San Mi - guel y San José de Comondú, dos comunidades-oasis de Baja California Sur, México, en el contexto de una política pública que promueve su crecimiento con base en la ex - plotación de su potencial turístico. Con esto se pretende ofrecer un marco de referencia para comprender la cultu - ra ambiental y de manejo hídrico en esas poblaciones, así como ofrecer opciones para un mejor uso de este recurso en una zona vulnerable, que es representativa de localida - des sudcalifornianas aisladas, pero en vías de integración a los procesos económicos y de urbanización que se viven en la entidad.

  14. POLÍTICAS PÚBLICAS DE JUVENTUD EN BAJA CALIFORNIA (1983-2002: AVANCES ADMINISTRATIVOS Y DESAFÍOS POLÍTICO-CULTURALES

    Directory of Open Access Journals (Sweden)

    Alejandro Monsiváis Carrillo

    2004-01-01

    Full Text Available A partir del análisis de las políticas públicas de juventud en Baja California durante el período 1983-2002, se muestra que, paralelamente al desarrollo de instituciones que buscan la eficiencia en la administración pública, se reproducen sistemas de creencias y prácticas de naturaleza política. Las transformaciones de las políticas públicas de juventud en esta entidad van acompañadas de una noción de juventud que representa una dificultad intrínseca para el desarrollo de una política pública efectiva. Lo juvenil, desde la mirada gubernamental, aparece como una condición de la vida privada de los individuos, ante la cual el Estado asume una posición tutelar. El impacto de esta situación en la cultura política es poco propicio para la socialización de los jóvenes como ciudadanos democráticos.

  15. Surgimiento, formación y persistencia de organizaciones sociales para la pesca ribereña de la península de Baja California

    Directory of Open Access Journals (Sweden)

    Saudiel Ramírez Sánchez

    2011-01-01

    Full Text Available Con un enfoque comparativo se exploraron las condiciones en que surgieron y han perdurado las organizaciones sociales para la pesca ribereña, en la península de Baja California. En la actualidad operan más de trescientas, e incluyen cooperativas pesqueras, sociedades de producción rural y de solidaridad social y uniones de pescadores. Los factores que han contribuido a su formación son la lógica de los pescadores, los incentivos institucionales y los actores externos, y hay otros que parecen perjudicar su persistencia como los incentivos organizativos, inversión en capital fijo y social, la solidaridad social, como principio rector de sus actividades, y la capacidad de autogestión. La presente evaluación es un primer paso para entender las condiciones en las que estas organizaciones han participado y pueden hacerlo, para mejorar la gestión de los recursos pesqueros de la región.

  16. Captura de atún aleta azul en Baja California, México: ¿pesquería regional o maquiladora marina?

    Directory of Open Access Journals (Sweden)

    Raúl Jesús del Moral-Simanek

    2009-01-01

    Full Text Available El atún aleta azul, capturado por la flota mexicana en las costas de la península de Baja California, se destinaba al enlatado local, para ofrecer a los consumidores nacionales un producto barato y con valor nutritivo alto. Sin embargo, esto cambió en la última década con la llegada de inversionistas, sobre todo japoneses. Ahora el atún se captura, engorda y exporta a los mercados japonés y estadounidense, que pagan un precio elevado, para satisfacer su demanda de sashimi. Esto tiene repercusiones positivas en el orden social y económico en México y Japón; determinadas a partir del trabajo de campo directo e indirecto realizado en el marco de esta investigación. Además, se identificaron algunas similitudes entre el comportamiento de las empresas estudiadas y la industria maquiladora de exportación, lo que abrió un debate sobre el tema.

  17. Red de participación institucional en las áreas naturales protegidas de la península de Baja California

    Directory of Open Access Journals (Sweden)

    Nain Martínez

    2015-01-01

    Full Text Available con el análisis de redes sociales se estudió la gobernanza de las áreas naturales protegidas de la península de Baja California, a través de su red de participación de 2007 a 2011, y se encontró que ésta se amplió y diversificó. Además, se presentó un fortalecimiento de la escala de gestión regional y una mayor inclusión de los actores sociales interesados en el uso de los recursos y la conservación ambiental. Sin embargo, el efecto en los participantes sobre la red es diferenciado. Así, mientras las instituciones gubernamentales, los académicos y las organizaciones de la sociedad civil incrementaron su influencia, la participación de los actores comunitarios y privados fue restringida. Es necesario profundizar en la investigación sobre la gobernanza y mejorar los mecanismos de participación.

  18. Componentes de cambio y economía regional: El sector manufacturero en el estado de Baja California y en el municipio de Mexicali (1985-1988

    Directory of Open Access Journals (Sweden)

    Ma. Dolores Sánchez Soler

    1992-01-01

    Full Text Available Este trabajo se realizó con dos propósitos: el primero es comparar los cambios manifestados en la estructura del empleo manufacturero durante el período de 1985-1988, en el municipio de Mexicali, en relación con el estado de Baja California y el país en su conjunto; para ello se hace uso de la técnica de cambio y participación (shift & share utilizando la información de los censos económicos: El segundo, relacionado con el anterior, se refiere a la aplicación de las tres versiones de dicha técnica a fin de determinar cuál de éstas presenta mayores elementos para la descripción de los cambios observados. El trabajo muestra que la entidad presenta ventajas de localización en las actividades de manufactura de productos metálicos, maquinaria y equipos e instrumentos quirúrgicos y de precisión; mientras que en Mexicali se registran ventajas para las actividades de papel y productos de papel y productos minerales no metálicos, aun cuando no se reporta especialización.Finalmente, se concluye que el modelo síntesis, presentado por Bishop y Simpson, es el que aporta mayores elementos para la descripción.

  19. Interacciones de pesquerías ribereñas en Bahía Magdalena-Almejas, Baja California Sur

    Directory of Open Access Journals (Sweden)

    Miguel A. Ojeda Ruiz de la Peña

    2012-01-01

    Full Text Available Con el fin de aportar al desarrollo de un modelo conceptual sobre la pesca ribereña o artesanal en el área de Bahía Magdalena-Almejas, Baja California Sur, se jerarquizó la importancia de 14 pesquerías de la región. La calificación se basó en un análisis cualitativo por puntos y en la estimación de un índice de importancia relativa, con indicadores como los promedios de captura, valor y frecuencia de registro de especies objetivo en desembarcos de embarcaciones menores, de 1998 a 2009; entre ellas están: almeja catarina, escama, camarón, callo de hacha, tiburón, jaiba, calamar, almeja pata de mula, rayas, lisa, pulpo, abulón, langosta y caracol chino. La interacción temporal entre varias de ellas es controlada por vedas oficiales, pero cuando ocurre se reconocen posibles efectos por pesca incidental e ilegal y modificaciones al ecosistema.

  20. Update: mercury poisoning associated with beauty cream--Arizona, California, New Mexico, and Texas, 1996.

    Science.gov (United States)

    1996-07-26

    During September 1995-May 1996, the Texas Department of Health (TDH), the New Mexico Department of Health (NMDH), and the San Diego County (California) Health Department investigated three cases of mercury poisoning associated with the use of a mercury-containing beauty cream produced in Mexico. The ongoing investigation has found this product in shops and flea markets in the United States located near the U.S.-Mexico border, and a U.S. distributor has been identified in Los Angeles. The cream, marketed as "Crema de Belleza--Manning" for skin cleansing and prevention of acne, listed "calomel" (mercurous chloride [Hg2Cl2]) as an ingredient and contained 6% to 10% mercury by weight. This report presents findings of a continuing investigation by these health departments, the Arizona Dept of Health Services (ADHS), California State Department of Health Services (CSDHS), the Food and Drug Administration (FDA), and CDC.

  1. Derechos colectivos y consulta previa: territorio cucapá y recursos pesqueros en Baja California, México

    OpenAIRE

    Alejandra Navarro Smith; Yacotzin Bravo Espinosa; Catalina López-Sagástegui

    2015-01-01

    Las demandas de reconocimiento de derechos territoriales y de uso de los recursos naturales que los pescadores cucapás le hacen al Estado mexicano, desde 1993, después de la creación de la Reserva del Alto Golfo de California y Delta del Río Colorado (en adelante, la Reserva), son unas más en el panorama de los problemas socioambientales y de despojo territorial, que afectan a los pueblos originarios en México. La característica particular en este caso es que el Estado mismo es quien construy...

  2. Algunas propuestas metodológicas para el estudio de la Baja California durante la segunda mitad del siglo XIX

    Directory of Open Access Journals (Sweden)

    Aidé Grijalva Larrañaga

    1987-09-01

    Full Text Available La presente constituye una interpretación en términos socioeconómicos de los acontecimientos bajacalifornianos durante la segunda mitad del siglo XIX, vinculando estos sucesos locales a las políticas centrales así como a los intereses extranjeros. Existen dos grandes vertientes de análisis en el estudio de este periodo de la historia bajacaliforniana. La primera vertiente está estrechamente vinculada con el estudio de la historia del sur de California y de los Estados Unidos. La otra vertiente habla de las especificidades que presentaba la península durante el periodo de estudio.

  3. Water flowing north of the border: export agriculture and water politics in a rural community in Baja California.

    Science.gov (United States)

    Zlolniski, Christian

    2011-01-01

    Favored by neoliberal agrarian policies, the production of fresh crops for international markets has become a common strategy for economic development in Mexico and other Latin American countries. But as some scholars have argued, the global fresh produce industry in developing countries in which fresh crops are produced for consumer markets in affluent nations implies “virtual water flows,” the transfer of high volumes of water embedded in these crops across international borders. This article examines the local effects of the production of fresh produce in the San Quintín Valley in northwestern Mexico for markets in the United States. Although export agriculture has fostered economic growth and employment opportunities for indigenous farm laborers, it has also led to the overexploitation of underground finite water resources, and an alarming decline of the quantity and quality of water available for residents’ domestic use. I discuss how neoliberal water policies have further contributed to water inequalities along class and ethnic lines, the hardships settlers endure to secure access to water for their basic needs, and the political protests and social tensions water scarcity has triggered in the region. Although the production of fresh crops for international markets is promoted by organizations such as the World Bank and Inter-American Development Bank as a model for economic development, I argue that it often produces water insecurity for the poorest, threatening the UN goal of ensuring access to clean water as a universal human right.

  4. Caracterización del peligro por inundaciones en el oasis La Purísima, Baja California Sur, México

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    Jobst Wurl

    2015-01-01

    Full Text Available En el estado de Baja California Sur existen solo cuatro oasis con extensiones mayores a 2.0 km 2 ; La Purísima (2.25 km 2 representa el tercero en extensión. En el pasado el oasis fue frecuentemente afectado por inundaciones resultantes de los eventos extremos de precipitación, que generaron graves daños en la cuenca. Se realizó un diagnóstico del oasis La Purísima, con respecto a posibles inundaciones como consecuencia de lluvias extremas, lo cual incluye el análisis estadístico de la precipitación para la elaboración de un modelo hidrológico e hidráulico, con el fin de calcular el caudal máximo, el volumen y la frecuencia de crecidas en los cursos del arroyo Cadegomo bajo diferentes escenarios de lluvias extremas. Finalmente se elaboró un mapa de peligro por inundación según los escenarios elaborados Se efectuó un análisis de la ocurrencia de inundaciones en el pasado y sus efectos en el oasis por medio de evidencias históricas de inundación de la zona, para verificar su posible aplicación en la calibración de los modelos. Los caudales resultantes de los eventos de precipitación extremos generan un incremento importante de los niveles en el drenaje de la cuenca. La respuesta del arroyo es un incremento en el área de inundación de hasta 14% respecto al tiempo de retorno de 20 años. Un evento de 1 000 años generaría un incremento en el área de inundación de 67% y bajas, afectando las zonas de la región urbana, así como todos los lotes de cultivo

  5. Diferentiation of Basements Types Using Seismic Reflection Data and 40Ar-39Ar Dating in the Western Half of the Farallon Basin (gulf of California, Mexico)

    Science.gov (United States)

    Piñero Lajas, D.; González Fernández, A.; López-Martínez, M.; Lonsdale, P.; Kluesner, J.

    2009-04-01

    The Gulf of California is an active continental rift with an oblique right lateral displacement. Defining a clear boundary between continental and oceanic crust is difficult due to the high sedimentation rate. The new crust is a mixture of sills and sediments that do not produce aligned magnetic anomalies. The main objective of this work is to identify this boundary in the western part of the Farallon Basin. In order to accomplish this goal we used multichannel 2D high-resolution seismic reflection data taken during a cruise aboard oceanographic vessel Francisco de Ulloa in 2006. We also used petrological characterization and 40Ar-39Ar dating of continental samples collected in nearby Santa Catalina, Santa Cruz and San Diego islands, Punta Botella in the Baja California Peninsula, and marine samples of the continental margin next to Las Animas island (ROCA 2008 cruise). Oceanic crust created in the Farallòn spreading axis is identified primarily by saucer-shaped structures in the seismic profiles, which are interpreted as sills. The plutonic continental basement is located on the westernmost part of the margin and is recognized by a continuous high amplitude reflector. There are also volcanic patches in this area, like the South Farallon Massif, which are evident as discontinuities in the high amplitude reflector and with a different seismic character. The Farallon Basin is affected by two different tectonic regimes, the first (compressive) is related to the subduction of the Farallon Plate under the North American Plate, when the plutonic basement was originated. It consists of granodiorites and tonalites belonging to two phases of subduction during the Upper Cretaceous and Early Miocene. Outcrops of the latter phase are exposed in the peninsula of Baja California (Conception Bay); Mexico mainland (middle Sinaloa); and dredged samples of Pescadero Basin. These are similar to the plutonic Santa Catalina Island outcrop described and dated in this study. These

  6. of the U. S.-Mexico Border

    Directory of Open Access Journals (Sweden)

    Sophie Meritet

    2006-01-01

    Full Text Available This paper studies the possible impacts of liquefied natural gas (LNG projects on natural gas prices on both sides of the U. S.-Mexico border in California. In that state gas prices are high and demand is expected to grow. Several projects for LNG facilities have been proposed and have to cope with public opinions against them. In Baja California, four LNG projects are under development given the rising demand forecasted for the next years. After a detailed study of the opportunity for LNG projects, we conclude with an analysis of the fundamentals of the current and future price formation in both sides of the U. S.- Mexico border.

  7. Persistent organic pollutants associated to water fluxes and sedimentary processes in the Colorado River delta, Baja California, México.

    Science.gov (United States)

    Lugo-Ibarra, K C; Daesslé, L W; Macías-Zamora, J V; Ramírez-Álvarez, N

    2011-09-01

    Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were studied in sediment cores from two distinctive modern channels of the Colorado River (CR) delta. Their abundance and temporal changes are associated with flood-flows from the CR across the USA-Mexico border. The CR channel is directly exposed to river flood-flows while the Hardy River (HR) is a local channel derived mainly from agricultural runoff, geothermal effluents, and treated urban wastewater. Different headwater compositions and degrees of exposure to flood-flows appear to be the factors controlling the composition of persistent organic pollutants (POPs). Enrichment of OCPs (46 ng g(-1) dwt in HR and 4.37 ng g(-1) dwt in CR) occurred during or a few years after flooding. PCB-138 (4.2 ng g(-1)dwt) is enriched in HR suggesting its origin in dielectric oils from the geothermal power plant. PCB-28 (2.1 ng g(-1)dwt) in CR may be related with atmospheric input and/or re-deposition of upstream sediments. In surficial sediments (0-3 cm), only HR exceeds international sediment quality guidelines (4,4'-DDE=8.16 ng g(-1)dwt and ΣDDT=8.34 ng g(-1)dwt).

  8. [Relationship of food groups intake and C-reactive protein in healthy adults from Mexicali, Baja California, México].

    Science.gov (United States)

    Ruiz-Esparza, Josefina; Robinson-Navarro, Octavio; Ortega-Vélez, María Isabel; Diaz-Molina, Raúl; Carrillo-Cedillo, Eugenia Gabriela; Soria-Rodriguez, Carmen G

    2013-09-01

    The high sensitivity C-reactive protein (hs-CRP) is an important biomarker in inflammatory processes. The objective was to analyze the relationship between the concentrations of hs-CRP in adults from a northern Mexico region with their typical food intake patterns. A sample of 72 university professors underwent clinical and anthropometric assessments and their hs-CRP levels were quantified with an immunoenzymometric assay. Additionally, they filled out a food intake frequency questionnaire, from which the servings of different food groups were obtained with the ESHA software. The average age of participants was 49.75 +/- 10.05 years and the average hs-CRP concentration was 1.66 (0.97, 3.52) mg/L. The value of the association between fruit consumption and hs-CRP level was protective, according to the logistic regression analysis, being the Odds Ratio (OR) 0.23 (95% CI: 0.05, 1.03); while for vegetables the OR was 0.66 (95% CI: 0.12, 3.68). Furthermore, high protein content foods, dairy products, oils and fats were associated with elevated levels of hs-CRP. In conclusion, in our study, the intake of some food groups like fruits and vegetables, and to a lesser extent cereals, were associated with low values of hs-PCR.

  9. Effects of upwelling, tides and biological processes on the inorganic carbon system of a coastal lagoon in Baja California

    Science.gov (United States)

    Ribas-Ribas, M.; Hernández-Ayón, J. M.; Camacho-Ibar, V. F.; Cabello-Pasini, A.; Mejia-Trejo, A.; Durazo, R.; Galindo-Bect, S.; Souza, A. J.; Forja, J. M.; Siqueiros-Valencia, A.

    2011-12-01

    The role of coastal lagoons and estuaries as sources or sinks of inorganic carbon in upwelling areas has not been fully understood. During the months of May-July, 2005, we studied the dissolved inorganic carbon system in a coastal lagoon of northwestern Mexico during the strongest period of upwelling events. Along the bay, different scenarios were observed for the distributions of pH, dissolved inorganic carbon (DIC) and apparent oxygen utilization (AOU) as a result of different combinations of upwelling intensity and tidal amplitude. DIC concentrations in the outer part of the bay were controlled by mixing processes. At the inner part of the bay DIC was as low as 1800 μmol kg -1, most likely due to high water residence times and seagrass CO 2 uptake. It is estimated that 85% of San Quintín Bay, at the oceanic end, acted as a source of CO 2 to the atmosphere due to the inflow of CO 2-rich upwelled waters from the neighboring ocean with high positive fluxes higher than 30 mmol C m -2 d -1. In contrast, there was a net uptake of CO 2 and HCO 3- by the seagrass bed Zostera marina in the inner part of the bay, so the pCO 2 in this zone was below the equilibrium value and slightly negative CO 2 fluxes of -6 mmol C m -2 d -1. Our positive NEP and ΔDIC values indicate that Bahía San Quintín was a net autotrophic system during the upwelling season during 2005.

  10. [Echinoderms (Echinodermata) from the Gulf of California, Mexico].

    Science.gov (United States)

    Solís-Marín, Francisco A; Laguarda-Figueras, Alfredo; Durán-González, Alicia; Ahearn, Cynthia Gust; Torres Vega, Juan

    2005-12-01

    A systematic list of the echinoderms of the Gulf of California, based on museum specimens of the Colección Nacional de Equinodermos, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autónoma de México and the National Museum of Natural History, Smithsonian Institution, Washington, D.C. is presented. A total of 193 echinoderm species is recorded, distributed in 108 genera, 51 families and 19 orders. 12 new records for the Gulf of California are presented: Asteroidea (four), Ophiuroidea (three) and Holothuroidea (five).

  11. Educación para la prevención del VIH-SIDA para inmigrantes indígenas en Baja California

    Directory of Open Access Journals (Sweden)

    Elizabeth Maier

    2007-01-01

    Full Text Available El objetivo del presente artículo es anclar el análisis de una experiencia de investigación-acción en educación, para la prevención del VIH-SIDA en comunidades indígenas inmigrantes en Baja California, a un marco teórico y fenomenológico que organice las dimensiones múltiples de la problemática, y permita mayor comprensión del significado de la pandemia para estas comunidades, el sentido de la participación de las actoras principales del proyecto, sus resultados, las implicaciones de la articulación de la perspectiva de género y una orientación cultural para su éxito. Se utiliza la categoría vulnerabilidad, para ejemplificar las condiciones de vida tan frágiles de las comunidades indígenas de origen y recepción, los significados subalternos de la identidad tradicional de las indígenas y los riesgos propios de la migración. El artículo interpreta el ejercicio de promoción de la salud comunitaria a partir del sentido cultural de género de las comunidades de origen, los significados históricos y subjetivos de la emigración indígena creciente y los ensayos consiguientes de reorganización social, cultural y genérica, causados por la dislocación migratoria. A partir de este complejo rompecabezas teórico, histórico, fenomenológico y relacional, en los últimos apartados se examina la mecánica del proyecto, sus contenidos y el cúmulo de resultados que la experiencia arrojó a la comunidad y a las promotoras.

  12. Cambio de uso del suelo y vegetación en la Península de Baja California, México

    Directory of Open Access Journals (Sweden)

    Fernando Antonio Rosete Vergés

    2008-01-01

    Full Text Available Este trabajo analiza el cambio de uso de suelo y de vegetación en la Península de Baja California, al nivel de tipo de vegetación, durante el periodo 1978 (Serie I de INEGI a 2000 (Inventario Nacional Forestal a escala 1:250 000. Se realizó un análisis espacial de la información en ambiente de sistemas de información geográfica (SIG para identificar los cambios durante el periodo analizado. Se elaboró una matriz de transición y se agruparon los cambios encontrados en tres procesos principales de cambio de uso del suelo: desmatorralización, recuperación y crecimiento de manchas urbanas (como un indicador de urbanización. En el periodo analizado (22 años se dan cambios en el 7.7 % del territorio peninsular. Los procesos de desmatorralización y urbanización son más intensos en la zona norte de la pe¬nínsula, mientras que la recuperación es mayor en la zona sur. La desmatorralización para actividades agropecuarias es la más importante en la península. La urbanización en magnitud es el proceso menos importante, pero durante el periodo analizado la superficie ocupada por los asentamientos humanos se incrementó en casi un 270 %.

  13. Derechos colectivos y consulta previa: territorio cucapá y recursos pesqueros en Baja California, México

    Directory of Open Access Journals (Sweden)

    Alejandra Navarro Smith

    2015-07-01

    Full Text Available Las demandas de reconocimiento de derechos territoriales y de uso de los recursos naturales que los pescadores cucapás le hacen al Estado mexicano, desde 1993, después de la creación de la Reserva del Alto Golfo de California y Delta del Río Colorado (en adelante, la Reserva, son unas más en el panorama de los problemas socioambientales y de despojo territorial, que afectan a los pueblos originarios en México. La característica particular en este caso es que el Estado mismo es quien construye los marcos legales en materia de protección a las especies —sin consultar debidamente a dichos pueblos—, volviendo ilegal la presencia cucapá en esa zona y vulnerando sus derechos como población indígena del delta. En consecuencia, las autoridades medioambientales y de pesca mexicanas han constituido la zona del delta del río Colorado como un territorio en disputa, al implementar esquemas de protección ambiental y de pesca, sustentados en modelos disciplinarios, que únicamente se alimentan de información biológica y pesquera. El conflicto se genera cuando se deja al elemento humano fuera de los análisis, como si las comunidades asentadas en los territorios protegidos y usuarias de los recursos no formaran parte de los ecosistemas. Al crear el núcleo de la Reserva en el mismo lugar donde se encontraban los campamentos de pesca del pueblo cucapá se volvió ilegal el aprovechamiento de los recursos pesqueros en la zona. En este contexto se han criminalizado las acciones de resistencia con las que los cucapás responden ante la regulación medioambiental del delta del río Colorado. Al ver imposibilitada la continuidad de su práctica pesquera, los habitantes se organizan para defender su acceso al territorio y, en un sentido más amplio, sus formas de vida y de trabajo. Este caso, en particular, visibiliza maneras contemporáneas por las que el Estado despoja el territorio y desaparece prácticas culturales propias de los pueblos

  14. Estructura de la avifauna durante el periodo invierno-primavera en el Estero Rancho Bueno, Baja California Sur, México Structure of the avifauna during the winter-spring season in Estero Rancho Bueno, Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Edgar Amador

    2006-12-01

    Full Text Available Mensualmente, de noviembre de 1993 a junio de 1994, se contaron las aves en un ambiente de manglar en Estero Rancho Bueno de la costa occidental de Baja California Sur. Sumaron en total 5965 aves de 56 especies de 10 órdenes y 21 familias. La estacionalidad estuvo definida por 31 residentes, 22 migratorias y tres indeterminadas. La mayoría de las especies se consideran costeras y/o estuarinas; sin embargo, hay algunas terrestres. Existen indicios de que por lo menos 2 especies se reproducen en el área, 4 presentan alguna categoría en la normatividad y 5 se utilizan comercialmente. La comunidad de aves es más diversa a principios de invierno y disminuye hacia finales de primavera, coincidiendo con la menor riqueza de especies y el aumento en la dominancia del pelícano café (Pelecanus occidentalis, gaviota occidental (Larus occidentalis y gaviota pico anillado (Larus delawarensis. El análisis para las áreas con manglar y sin manglar indicó que el número total de individuos (N, el número de individuos de la especie más abundante (Nmax y la riqueza de especies (S son mayores en el hábitat de áreas abiertas, mientras que la equidad (E siempre fue mayor en el hábitat de manglar.Periodic surveys were conducted from November 1993 to June 1994 in Estero Rancho Bueno, a mangrove lagoon environment on the west coast of Baja California Sur. We found 5,65 birds (56 species. The avifauna included 31 resident, 22 migratory, and 3 species of undeterminated migratory status. Most of the species were coastal and estuarine birds; however there were some terrestial and wide-ranging birds. There is evidence that at least 2 species breed in the area; 4 species are protected by Mexican law and 5 species have commercial value. Different indices show that the bird community diversity is lower by the end of spring and the dominance of the Brown Pelican (Pelecanus occidentalis, the Western Gull (Larus occidentalis, and the Ring-billed Gull (L. delawarensis

  15. A review on advances in seismology in Mexico after 30 years from the 1985 earthquake

    Science.gov (United States)

    Castro, Raúl R.; Pérez-Campos, Xyoli; Zúñiga, Ramón; Ramírez-Guzmán, Leonardo; Aguirre, Jorge; Husker, Allen; Cuéllar, Armando; Sánchez, Tomás

    2016-10-01

    The 19 September 1985 (Mw8.1) earthquake, located on the Michoacán coast, Mexico, generated great damage in Mexico City, more than 300 km away from the epicentral area. Other important cities near the coast and in central Mexico also suffered severe damage. Thirty years after this important event, the National Autonomous University of Mexico (UNAM), the Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE) and other institutions organized a conference to discuss the scientific advances, particularly in seismology, that had taken place in Mexico since then.

  16. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    Science.gov (United States)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  17. Impacto espacial diferenciado en el consumo y adicción a las drogas en la frontera norte de México: el caso del Estado de Baja California

    Directory of Open Access Journals (Sweden)

    Pablo Jesús González Reyes

    2011-12-01

    Full Text Available En el artículo se resalta la distribución del uso de drogas en México, destacando el papel de la región del norte, la cual presenta los porcentajes de consumo más altos del país. A un nivel más específico, se abordan las implicaciones individuales y sociales en el abuso del consumo de bebidas alcohólicas entre la población, así como los efectos del ambiente familiar, trayectorias escolares y laborales de los adictos a las drogas ilícitas en Baja California, al igual que las correlaciones estadísticas entre adicción a drogas y otras variables sociales. El objetivo principal fue evidenciar el impacto espacial diferenciado que tiene el proceso del consumo de drogas en México. Para esto, se utilizaron datos empíricos provenientes de encuestas nacionales de adicciones de los años 1993, 1998, 2002 y 2008, coordinadas por la Secretaría de Salud, e información generada a través de diversos estudios realizados en Baja California, a efectos de dimensionar este problema de salud a nivel local. Los resultados concluyen que la región norte de México presenta un efecto más severo en el problema del uso y abuso de drogas, figurando de manera primordial el Estado de Baja California.

  18. Aplicación de un modelo bioeconómico a la pesquería el erizo rojo, Strongylocentrotus franciscanus, de la costa noroccidental de Baja California, México

    OpenAIRE

    Yunuen Canedo López; Michel Jules Dreyfus León; Alfredo Cota Villavicencio

    1999-01-01

    La pesquería del erizo rojo, Strongylocentrotus franciscanus, recurso importante de Baja California, ha dado muestras de sobreexplotación. Se aplicaron los modelos de rendimiento por recluta y de optimización dinámica de Beverton y Holt para encontrar la talla de primera captura que permite optimizar ganancias y tratar de asegurar la permanencia del recurso para futuras generaciones. Los parámetros biológicos usados fueron = 155 mm, K = 0.22 y M = 0.22. El modelo de rendimiento por recluta s...

  19. Halocoryza Alluaud 1919, sea-side beetles of the Indian, Atlantic (sensu lato, and Pacific Oceans: a generic synopsis and description of a remarkable new species from Baja California Sur, México (Coleoptera, Carabidae, Scaritini, Clivinina

    Directory of Open Access Journals (Sweden)

    Terry Erwin

    2011-09-01

    Full Text Available Information on the three previously described species of Halocoryza Alluaud is updated and a new species for the genus from Isla Carmen, Sea of Cortés, Baja California Sur, México is described. Halocoryza whiteheadiana sp. n. was found at UV light on a beach of that island. This species does not fit the profile of the other three species, i.e., living on coralline beach sands, or in the Mangrove intertidal zone. Two alternative possibilities as to why this is so are suggested and a study plan for testing these possibilities is proposed.

  20. La academia y el sector productivo en Baja California. Los actores y su capacidad de vinculación para la producción, difusión y trasferencia del conocimiento y la innovación

    OpenAIRE

    Minerva Celaya Tentori; María del Rosio Barajas E.

    2012-01-01

    En el artículo se analizan las capacidades de vinculación de las instituciones de educación superior y los centros científicos de Baja California con el sector productivo, enfocadas a incentivar los procesos de producción, difundir y trasferir conocimiento, promover la innovación, así como generar la competitividad de las empresas ahí localizadas. Se parte de la perspectiva teórica de Edith Penrose (1980) sobre el llamado resource-based view, donde las capacidades y recursos son elementos ese...

  1. Variabilidad geográfica de la concentración de Hg, Co, Fe y Ni en mejillones Mytilus californianus (Conrad, 1837) de la costa de Baja California

    OpenAIRE

    E. A. Gutiérrez Galindo; A. Muñoz Barbosa

    2003-01-01

    En este estudio se determinó la distribución espacial de la contaminación por Hg, Fe, Co y Ni en la costa noroccidental de Baja California mediante el uso del mejillón Mytilus californianus como biomonitor. Durante febrero y julio de 1994 se realizaron muestreos de mejillones en ocho localidades situadas a lo largo de 300 km de costa, desde Punta Bandera (10 km al sur de la frontera México-EUA) hasta San Quintín (300 km al sur de la frontera). La distribución espacial de Hg presentó un gradie...

  2. La Asociación de Bibliotecarios de Baja California (ABIBAC) y su participación en la formación de los bibliotecarios bajacalifornianos, 2003-2009

    OpenAIRE

    2011-01-01

    Los antecedentes de la Asociación de Bibliotecarios de Baja California, abibac, son una serie de eventos académicos realizados en nuestro estado desde 1989, tales como los talleres de entrenamiento en Bibliotecología, el Diplomado sistemas y procesos electrónicos aplicados al manejo de la información en bibliotecas, los cursos Evaluación de revistas científicas, y teoría y método del servicio de información y referencia, así como los cursos de Evaluación de sistemas y servicios de información...

  3. Geophysical exploration with transient electromagnetic soundings in three geothermal zones of Baja California, Mexico: Tres Virgenes, Puertecitos and Bahia Concepcion; Exploracion geofisica con sondeos electromagneticos transitorios en tres zonas geotermicas de Baja California, Mexico: Tres Virgenes, Puertecitos y Bahia Concepcion

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Carlos; Vazquez, Rogelio; Gonzalez, Carlos A; Romo, Jose M; Velasco, Nector; Lopez, Addier [CICESE, Ensenada, B.C. (Mexico)

    1999-04-01

    The results obtained from transient electromagnetic soundings (TDEM) applied to three geothermal zones are briefly commented, emphasizing instead the out of contract work done by the Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (CICESE), both in the application of other geophysical techniques and the subsequent data analysis. This work includes several VLF (very low frequency) electromagnetic profiles in Bahia Concepcion and a magnetotelluric profile in Puertecitos. Regarding the data analysis, an algorithm to assess stratified models was constructed and applied to several Bahia Concepcion soundings and to the TDEM and Schlumberger data from Tres Virgenes in order to compare the resolving powers of these methods. Finally an imaging procedure based on smoothness constraints is being applied nowadays to characterize the geometry of the electric conductors under the Tres Virgenes hot springs. [Spanish] Se comentan los resultados de la aplicacion del modo de sondeo electromagnetico transitorio (TDEM) en tres zonas geotermicas, dando enfasis al trabajo realizado fuera de contrato por el Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (CICESE), tanto en la aplicacion de otras tecnicas geofisicas como en el analisis posterior de los datos. Estos trabajos comprenden el levantamiento de perfiles electromagneticos con el metodo VLF (very low frequency) en Bahia Concepcion y de un perfil magnetotelurico en Puertecitos. En relacion con analisis de los datos, se implemento un algoritmo de evaluacion de modelos estratificados, usandose en sondeos de Bahia Concepcion. Esta tecnica se aplico a los datos TDEM y Schlumberger de Tres Virgenes para comparar sus poderes de resolucion. Finalmente, un procedimiento de construccion de imagenes de resistividad, basado en condiciones de suavidad, se esta aplicando actualmente a los datos de Tres Virgenes para caracterizar la geometria de los conductores electricos bajo las manifestaciones hidrotermales.

  4. Synthesis of gravity, magnetic and thermal studies at the Las Tres Virgenes geothermal zone, Baja California Sur, Mexico. Sintesis de los estudios de gravimetria, magnetometria y termometria en la zona geotermica de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Estrada, Gerardo (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)); Gonzalez Lopez, Macario (Residencia General de Cerro Prieto, Mexicali (Mexico))

    1998-01-15

    Las Tres Virgenes geothermal zone is located in the NE-SW central sector of a sigmoidal basin that regionally has a NW-SE trend. In the local deepest zone there is a NE-SE granodioritic basement horst acting as hydrologic barrier, that makes the fluids flow up. After moving in a direction parallel to the local horst, waters continue its regional SE-NW movement controlled by regional tectonics. The flanks of the granodioritic basement horst, and local N-S faulting act as fluid paths in the hydrothermal zone, but regional NW-SE regional faults determine the general flow direction. Both regional and local tectonics show magnetic evidences of the emplacement of magmatic bodies of intermediate to basic composition. Those along NW-SE trends are more noticeable but we consider they are not the present day heat source. Intermediate magmatism along NE-SW local trend seems to be less extensive but it is younger, so, we consider it constitutes the heat source of the hydrothermal system. Thermal data suggest that the heat source is located below the volcanic chain toward the S or SW of the wells, phenomena related with the general displacement of magmatism from NE to SW along the volcanic chain. However, recent intensive faulting permits a higher permeability in the northern sector in which there are slightly smaller temperatures but at shallower depths and with higher flow rates.

  5. La micro y pequeña empresa como generadora de empleo en Baja California durante la crisis de 2008-2009

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray Lagarda

    2016-01-01

    Full Text Available El objetivo del trabajo ha sido evaluar la importancia de la conformación del tejido empresarial en la evolución de la actividad económica y la generación de empleo en Baja California en el entorno de la crisis global de 2008-2009, con énfasis en el comportamiento de la micro y pequeña empresa. Lo anterior se consigue a través de la metodología de un análisis de correspondencias de carácter exploratorio y otro econométrico con fines confirmatorios en los cuales se utilizaron variables de los estratos empresariales y los sectores económicos una vez revisados los indicadores poblacionales, migratorios y de la estructura productiva. Como resultados se encontró una relación directa y significativa de las microempresas con el volumen de negocios y el empleo durante la crisis, sin embargo, en el periodo post-crisis (2010-2014 la aportación de la pequeña empresa resultó muy superior. Por su parte, las grandes empresas, mostraron menor sensibilidad general y una reducción de su capacidad para generar empleo aún durante el periodo post-crisis. En cualquier caso, debemos señalar que la limitante es que los resultados deben ser tomados con cautela debido a la alta segregación por estrato. Se concluye que no es posible rechazar la hipótesis de que la micro, pero sobre todo la pequeña empresa jugó un papel estratégico en la generación de empleo y dinamismo económico durante el periodo de crisis, contribuyendo incluso a aminorar su impacto, por lo que se debe fortalecer una política industrial que favorezca el aprendizaje y la innovación de este sector empresarial.

  6. Structural and Seismic Stratigrapic study in the Center of the Magdalena Shelf in the Western Margin of Baja California Based on Seismic Reflection Data

    Science.gov (United States)

    González-Escobar, Mario; Salazar-Cárdenas, Rosa M.; Munguía, Luis; Martín, Arturo; Suárez-Vidal, Francisco

    2016-10-01

    The Magdalena Shelf is a shallow, low-relief surface located along the Baja California Pacific margin. As part of a forearc basin, the shelf was a convergent margin setting before the oblique divergent plate boundary formed in the Gulf of California at 12 Ma. It is thought that since 12-8 Ma, this basin has been a transtensional or strike-slip basin. To constrain the geometry, structural characteristics and some stratigraphic relationships, an active-source, seismic-reflection study was carried out in the central part of the shelf. As a result, the analyzed data show faults, basins and unconformities. Two out of four observed basins are clearly controlled by the Santa Margarita and San Lázaro faults that dip ~40° NE; a third basin is controlled by the Tosco-Abreojos fault. These three basins are part of the deformation zone that is associated with the Tosco-Abreojos fault system. The Iray-Margarita basin, on the other hand, is a fourth basin located at the northeast sector of the study area. An additional feature observed is a stepover lying between the overlapping ends of the Santa Margarita and San Lázaro faults. Small faults oriented sub-parallel to the above major faults are present, mainly throughout the western sector of the study area. Some of those minor faults cut through the seafloor indicating recent tectonic activity. Santa Margarita, San Lázaro and Tosco-Abreojos are also the names given to half-grabens controlled by the active faults that have the same names. The first two basins are affected by many more small faults in comparison with what we see in the third basin. Tectonically, this means that those two basins are the more active in the area of study. In all four basins, the upper seismic sequence consists of sediments controlled by faults of Neogene age. We found that the Iray-Santa Margarita basin is the deepest of all four basins (beyond the resolution of the data, >5 km), and lack of minor faults there indicates that the basin is not

  7. The supra-detachment tectono-sedimentary record of rifted margins: the example of the Los Barriles Basin, SE Baja California Sur.

    Science.gov (United States)

    Masini, Emmanuel; Robin, Cécile; Geoffroy, Laurent; Strzerzynski, Pierre

    2010-05-01

    The study of rifted margins have shown that the main controlling structures are changing from classical high-angle faults to low-angle detachment fault dominated extension when the crust thins to less than 10 km, which is the case in hyper-extended, magma-poor rifted margins. While the stratigraphic record related to classical high-angle faulting is well constrained, little is known about the tectono-sedimentary evolution of hyper-extended rift systems. A major question remains, how supra-detachment tectono-sedimentary systems are recorded in the stratigraphic record? This remains largely unexplored and must be better constrained by observations. In our poster, we present preliminary results from our study of a rift basin floored by a low-angle detachment system exposed at the southeastern edge of the Baja California Peninsula in the so-called Los Barriles area in the Gulf of California. This area represents one of the best examples of an active transtensional rift system from which the tectono-sedimentary evolution of the rift to drift transition can be studied in the field. The syn-tectonic sedimentary sequence is floored by a detachment fault and is limited oceanward by an extensional allochthon. The syn- to post-tectonic stratigraphy can be summarized into 4 main formations: (1) The Pescadero fluvial fm. (no available ages) evolves upsection from poorly organized polymictic in components and faulted breccias to more granitic and stratified conglomerates. It overlies the extensional allochthon and is tilted continentwards. The channel incisions show EW paleoflows and the upper Pescadero fm. is transitional to the following Refugio fm. (2) The overlying Refugio fm. (Lower Pliocene) occurs as thick marine sandy deposits within the basin axis, is granitic in composition and has average paleocurrents directions trending N-S. The upper part of the fm. is transitional to the following Barriles fm. (3) The Barriles fm. (Upper Miocene - Lower Pleistocene) occurs as very

  8. Structural and Seismic Stratigrapic study in the Center of the Magdalena Shelf in the Western Margin of Baja California Based on Seismic Reflection Data

    Science.gov (United States)

    González-Escobar, Mario; Salazar-Cárdenas, Rosa M.; Munguía, Luis; Martín, Arturo; Suárez-Vidal, Francisco

    2016-09-01

    The Magdalena Shelf is a shallow, low-relief surface located along the Baja California Pacific margin. As part of a forearc basin, the shelf was a convergent margin setting before the oblique divergent plate boundary formed in the Gulf of California at 12 Ma. It is thought that since 12-8 Ma, this basin has been a transtensional or strike-slip basin. To constrain the geometry, structural characteristics and some stratigraphic relationships, an active-source, seismic-reflection study was carried out in the central part of the shelf. As a result, the analyzed data show faults, basins and unconformities. Two out of four observed basins are clearly controlled by the Santa Margarita and San Lázaro faults that dip ~40° NE; a third basin is controlled by the Tosco-Abreojos fault. These three basins are part of the deformation zone that is associated with the Tosco-Abreojos fault system. The Iray-Margarita basin, on the other hand, is a fourth basin located at the northeast sector of the study area. An additional feature observed is a stepover lying between the overlapping ends of the Santa Margarita and San Lázaro faults. Small faults oriented sub-parallel to the above major faults are present, mainly throughout the western sector of the study area. Some of those minor faults cut through the seafloor indicating recent tectonic activity. Santa Margarita, San Lázaro and Tosco-Abreojos are also the names given to half-grabens controlled by the active faults that have the same names. The first two basins are affected by many more small faults in comparison with what we see in the third basin. Tectonically, this means that those two basins are the more active in the area of study. In all four basins, the upper seismic sequence consists of sediments controlled by faults of Neogene age. We found that the Iray-Santa Margarita basin is the deepest of all four basins (beyond the resolution of the data, >5 km), and lack of minor faults there indicates that the basin is not

  9. Trace Elements in the Marine Sediments of the La Paz Lagoon, Baja California Peninsula, Mexico: Pollution Status in 2013.

    Science.gov (United States)

    Pérez-Tribouillier, Habacuc; Shumilin, Evgueni; Rodríguez-Figueroa, Griselda Margarita

    2015-07-01

    To determine the actual concentrations of trace elements in surface sediments from the La Paz Lagoon, as well as their associations and possible origins, 91 sediment samples were analyzed for more than 50 elements using a combination of ICP-MS and ICP-AES. The results of a principal component analysis are used to distinguish four associative groups within the elements. Natural enrichment of As, Cd and U occurs due to the supply of weathered phosphorites from the El Cien formation located to the north-west of the lagoon. Sediment quality indices for potentially toxic trace elements do not show any probable impact on the biota of the lagoon. Only the concentrations of As in 30 % of the stations and Cu in 20 % of them exceed related effect range low levels. The highest concentration of Pb (36.8 mg kg(-1)) was measured in the sediments near the City of La Paz.

  10. Seasonal changes in a fish assemblage associated with mangroves in a coastal lagoon of Baja California Sur, Mexico

    OpenAIRE

    2011-01-01

    The fish assemblage in a coastal lagoon with mangroves known as Rancho Bueno was determined and associated with environmental parameters. We used an experimental otter trawl net to catch the fish, and 62 fish species were identified from 48 genera and 30 families. The most abundant species were: Etropus crossotus, Eucinostomus gracilis, Paralabrax maculatofasciatus, Sphoeroides annulatus, and Eucinostomus dowii. The water temperature changed seasonally, being warm from July through December...

  11. New Technologies and Learning Environments: A Perspective from Formal and Non-Formal Education in Baja California, Mexico

    Science.gov (United States)

    Zamora, Julieta Lopez; Reynaga, Francisco Javier Arriaga

    2010-01-01

    This paper presents results of two research works, the first approaches non-formal education and the second addresses formal education. In both studies in-depth interview techniques were used. There were some points of convergence between them on aspects such as the implementation of learning environments and the integration of ICT. The interview…

  12. Monitoring and modeling land subsidence at the Cerro Prieto Geothermal Field, Baja California, Mexico, using SAR interferometry

    Science.gov (United States)

    Carnec, Claudie; Fabriol, Hubert

    Images derived from repeat-pass spaceborne interferometric synthetic aperture radar (InSAR) systems offer the possibility of mapping surface deformation of small spatial extent and monitoring its spatio-temporal evolution. A slow local subsidence has been detected at the Cerro Prieto geothermal field from images acquired by the European Space Agency remote sensing satellites ERS-1/2 between 1993 and 1997. Although agricultural activity in the area limited the investigation, interferometric monitoring revealed that the ground deformation is associated with the withdrawal of geothermal fluid and agreed with the leveling data. Modeling of the subsidence was carried out assuming elastic deformation in a half-space from simple point sources, of which five were necessary to reproduce the fringe patterns observed on the interferograms. The depths and locations of three of the sources are compatible with the location of the known reservoir. The study improves prior knowledge of the displacement field and of the mecanisms involved in the subsidence phenomenon.

  13. Benchmarking of a bidimensional flood analysis with a structural measure in the catchment Rosarito Huahuatay Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Faustino De Luna C.

    2016-01-01

    Not necessarily, the works are constructed to reduce flood damages. Sometimes the water that temporarily occupied an area of land can be shifted to other areas where it could cause further injury; it is therefore advisable to make comprehensive basin-wide studies to evaluate the goodness of the proposed works, usually with simulation models embracing the basin where the floodplains are located…

  14. Active metasomatism in the Cerro Prieto geothermal system, Baja California, Mexico: a telescoped low pressure/temperature metamorphic facies series

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, P.; Elders, W.A.; Williams, A.E.; McDowell, S.D.; Bird, D.K.

    1983-01-01

    In the Cerro Prieto geothermal field, carbonate-cemented, quartzofeldspathic sediments of the Colorado River delta are being actively metasomatized into calc-silicate metamorphic rocks by reaction with alkali chloride brines between 200/sup 0/ and 370/sup 0/C, low fluid and lithostatic pressures, and low oxygen fugacities. Petrologic investigations of drill cores and cutting from over 50 wells in this field identified a prograde series of calc-silicate mineral zones which include as index minerals: wairakite, epidote, prehnite, and clinopyroxene. Associated divariant mineral assemblages are indicative of a very low pressure/temperature metamorphic facies series which encompasses the clay-carbonate, zeolite, greenschist, and amphibolite facies. This hydrothermal metamorphic facies series, which is becoming increasingly recognized in other active geothermal systems, is characterized by temperature-telescoped dehydration and decarbonation mineral equilibria. Its equivalent should now be sought in fossil hydrothermal systems.

  15. Hydrothermal-flow regime and magmatic heat source of the Cerro Prieto geothermal system, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Bird, D.K.; Williams, A.E.; Schiffman, P.

    1982-01-01

    This detailed three-dimensional model of the natural flow regime of the Cerro Prieto geothermal field, before steam production began, is based on patterns of hydrothermal mineral zones and light stable isotopic ratios observed in rock samples from more than fifty deep wells, together with temperature gradients, wireline logs and other data. At the level so far penetrated by drilling, this hydrothermal system was heated by a thermal plume of water close to boiling, inclined at 45/sup 0/, rising from the northeast and discharging to the west. To the east a zone of cold water recharge overlies the inclined thermal plume. Fission track annealing studies shows that the reservoir reached 170/sup 0/C only 10/sup 4/ years ago. Oxygen isotope exchange data indicate that a 12 km/sup 3/ volume of rock subsequently reacted with three times its volume of water hotter than 200/sup 0/C. Averaged over the duration of the heating event this would require a flow velocity of about 6 m/year through the pores of a typical cross section of the reservoir having an average porosity of 10%. Although this is an extensional tectonic environment of leaky transform faulting in which repeated intrusions of basalt magma are likely, for simplicity of computation possible heat sources were modelled as simple two dimensional basalt intrusions of various sizes, shapes and locations. We have calculated a series of two-dimensional convective heat transfer models, with different heat sources and permeability distributions. The models which produce the best fit for the temperature distributions observed in the field today have in common a heat source which is a funnel-shaped basalt intrusion, 4 km wide at the top, emplaced at a depth of 5 km to 6 km about 40,000 to 50,000 years ago.

  16. Fault Length Vs Fault Displacement Evaluation In The Case Of Cerro Prieto Pull-Apart Basin (Baja California, Mexico) Subsidence

    Science.gov (United States)

    Glowacka, E.; Sarychikhina, O.; Nava Pichardo, F. A.; Farfan, F.; Garcia Arthur, M. A.; Orozco, L.; Brassea, J.

    2013-05-01

    The Cerro Prieto pull-apart basin is located in the southern part of San Andreas Fault system, and is characterized by high seismicity, recent volcanism, tectonic deformation and hydrothermal activity (Lomnitz et al, 1970; Elders et al., 1984; Suárez-Vidal et al., 2008). Since the Cerro Prieto geothermal field production started, in 1973, significant subsidence increase was observed (Glowacka and Nava, 1996, Glowacka et al., 1999), and a relation between fluid extraction rate and subsidence rate has been suggested (op. cit.). Analysis of existing deformation data (Glowacka et al., 1999, 2005, Sarychikhina 2011) points to the fact that, although the extraction changes influence the subsidence rate, the tectonic faults control the spatial extent of the observed subsidence. Tectonic faults act as water barriers in the direction perpendicular to the fault, and/or separate regions with different compaction, and as effect the significant part of the subsidence is released as vertical displacement on the ground surface along fault rupture. These faults ruptures cause damages to roads and irrigation canals and water leakage. Since 1996, a network of geotechnical instruments has operated in the Mexicali Valley, for continuous recording of deformation phenomena. To date, the network (REDECVAM: Mexicali Valley Crustal Strain Measurement Array) includes two crackmeters and eight tiltmeters installed on, or very close to, the main faults; all instruments have sampling intervals in the 1 to 20 minutes range. Additionally, there are benchmarks for measuring vertical fault displacements for which readings are recorded every 3 months. Since the crackmeter measures vertical displacement on the fault at one place only, the question appears: can we use the crackmeter data to evaluate how long is the lenth of the fractured fault, and how quickly it grows, so we can know where we can expect fractures in the canals or roads? We used the Wells and Coppersmith (1994) relations between fault length and fault displacement to calculate fault length growth when displacement increase with time. We applied this relationship to the data collected, during the period 2004-2009, along the part of Cerro Prieto fault which is the SW limit of the Cerro Prieto pull-apart subsidence basin, and estimated that, for the present rate of subsidence, the length of rupture will migrate along the fault with a velocity of about 220 m/year.

  17. Waste Management in Mexico: key variables in play . The case of the Autonomous University of Baja California

    NARCIS (Netherlands)

    C. Armijo de Vega

    2006-01-01

    textabstractSoil pollution, water pollution, excessive levels of noise and air pollution are phenomena present wherever human have congregated in appreciable numbers. This has been taking place for centuries. As the human population increases and its activities diversify the impact on the environ

  18. A paleomagnetic investigation of vertical-axis rotations in coastal Sonora, Mexico: Evidence for distributed transtensional deformation during the Proto-Gulf shift from a subduction-dominated to transform-dominated plate boundary in the Gulf of California

    Science.gov (United States)

    Herman, Scott William

    The history of late Miocene (Proto-Gulf) deformation on the Sonoran margin of the Gulf of California is key to understanding how Baja California was captured by the Pacific plate and how strain was partitioned during the Proto-Gulf period (12.5-6 Ma). The Sierra el Aguaje and Sierra Tinajas del Carmen are located in southwestern coastal Sonora, Mexico, and represent the eastern rifted margin of the central Gulf of California. The ranges are composed of volcanic units and their corresponding volcaniclastic units which are the result of persistent magmatic activity between 20 and 8.8 Ma, including three packages of basalt and andesite that make excellent paleomagnetic recorders. Based on cross cutting relations and geochronologic data for pre-, syn-, and post-tectonic volcanic units, most of the faulting and tilting in the Sierra El Aguaje is bracketed between 11.9 and 9.0 Ma, thus falling entirely within Proto-Gulf time. A paleomagnetic investigation into possible vertical axis rotations in the Sierra el Aguaje has uncovered evidence of clockwise rotations between ~13º and ~105º with possible translations. These results are consistent with existing field relations, which suggest the presence of large (>45°) vertical axis rotations in this region. This evidence includes: a) abrupt changes in the strike of tilted strata in different parts of the range, including large domains characterized by E-W strikes b) ubiquitous NE-SW striking faults with left lateral-normal oblique slip, that terminate against major NW-trending right lateral faults, and c) obliquity between the general strike of tilted strata and the strike of faults. These rotations occurred after 12 Ma and largely prior to 9 Ma, thus falling into the Proto-Gulf period. Such large-scale rotations lend credence to the theory that the area inboard of Baja California was experiencing transtension during the Proto-Gulf period, rather than the pure extension that would be the result of strain partitioning

  19. Seismic structure beneath the Gulf of California: a contribution from group velocity measurements

    Science.gov (United States)

    Di Luccio, F.; Persaud, P.; Clayton, R. W.

    2014-12-01

    Rayleigh wave group velocity dispersion measurements from local and regional earthquakes are used to interpret the lithospheric structure in the Gulf of California region. We compute group velocity maps for Rayleigh waves from 10 to 150 s using earthquakes recorded by broad-band stations of the Network of Autonomously Recording Seismographs in Baja California and Mexico mainland, UNM in Mexico, BOR, DPP and GOR in southern California and TUC in Arizona. The study area is gridded in 120 longitude cells by 180 latitude cells, with an equal spacing of 10 × 10 km. Assuming that each gridpoint is laterally homogeneous, for each period the tomographic maps are inverted to produce a 3-D lithospheric shear wave velocity model for the region. Near the Gulf of California rift axis, we found three prominent low shear wave velocity regions, which are associated with mantle upwelling near the Cerro Prieto volcanic field, the Ballenas Transform Fault and the East Pacific Rise. Upwelling of the mantle at lithospheric and asthenospheric depths characterizes most of the Gulf. This more detailed finding is new when compared to previous surface wave studies in the region. A low-velocity zone in northcentral Baja at ˜28ºN which extends east-south-eastwards is interpreted as an asthenospheric window. In addition, we also identify a well-defined high-velocity zone in the upper mantle beneath central-western Baja California, which correlates with the previously interpreted location of the stalled Guadalupe and Magdalena microplates. We interpret locations of the fossil slab and slab window in light of the distribution of unique post-subduction volcanic rocks in the Gulf of California and Baja California. We also observe a high-velocity anomaly at 50-km depth extending down to ˜130 km near the southwestern Baja coastline and beneath Baja, which may represent another remnant of the Farallon slab.

  20. Isolation, characterization, and antibiotic resistance of Vibrio spp. in sea turtles from Northwestern Mexico

    OpenAIRE

    Zavala-Norzagaray, Alan A.; Aguirre, A. Alonso; Velazquez-Roman, Jorge; Flores-Villaseñor, Héctor; León-Sicairos, Nidia; Ley-Quiñonez, C. P.; Hernández-Díaz, Lucio De Jesús; Canizalez-Roman, Adrian

    2015-01-01

    The aerobic oral and cloacal bacterial microbiota and their antimicrobial resistance were characterized for 64 apparently healthy sea turtles captured at their foraging grounds in Ojo de Liebre Lagoon (OLL), Baja California Sur (BCS), Mexico (Pacific Ocean) and the lagoon system of Navachiste (LSN) and Marine Area of Influence (MAI), Guasave, Sinaloa (Gulf of California). A total of 34 black turtles (Chelonia mydas agassizii) were sampled in OLL and eight black turtles and 22 olive ridley tur...

  1. Comparative study of the amplification of ground motion using seismic noise and recent earthquakes adjacent to the Cerro Prieto volcano, Baja California

    Science.gov (United States)

    Vega, F. D.; Vidal-Villegas, A.

    2009-12-01

    We have chosen an area of approximately 79 km2, centered around the Cerro Prieto volcano, in the Mexicalli valley, Baja California, based on elevated registered acceleration data. The GEO station, located in the Cerro Prieto geothermal field has registered seismic accelerations on the order of 492 gales. The local residents near the study area have reported feeling numerous smaller magnitude earthquakes, compared to those of the nearby populated city of Mexicalli. Does there exist an amplified seismic signal in the area? If so, what is the cause of the amplification? The objective of our study is to answer these questions and determine the subsurface (0-50 m) structure in 4 specific sites. To obtain these answers, we registered seismic noise samples using short period seismometers (1 s), intermediate (5 s) and 16 bit recorders, along a linear profile which crosses the volcano with an 18 degree NE orientation. Furthermore, we analyzed ground-motion data (from 2004-2006), obtained from 24-bit accelerographs. Using both types of data (noise and accelegraphs) we calculated the H/V spectral ratios, and the relative ratios between both sites. To determine the subsurface structure, we used a unidimensional model of the H/V ratios, based on the methodology used by Huerta-Lopez et al., 2005. The H/V spectral ratios from the seismic noise adjacent to the volcano display amplitude of 1 in the frequency range (0.8 - 30 Hz). In contrast, the amplitude in the volcano crater (159 m.a.s.l.) was 6 in the frequency range (0.8 - 3 Hz). The average H/V relative ratio of the crater and the adjacent sites is 4, with frequencies between 0.8 and 1.2 Hz. The S-wave H/V ratios for the VCP acceleration station (110 m.a.s.l.), are near 8, with frequencies between 1 and 2. The H/V spectral ratios from the seismic noise for the geothermal field display amplitude of 4 for frequencies between 0.8 and 1.3 Hz, while the results from the S wave display amplitudes of 5 between 1.5 and 3 Hz. In the

  2. 2010年墨西哥Baja Mw7.2地震与中国玉树Mw6.9地震强地震动特征的对比研究%Comparison on characteristics of strong ground motion from two earthquakes with similar Mw : the Baja, Mexico, Mw7.2 and Yushu, China, Mw6.9 earthquake in 2010

    Institute of Scientific and Technical Information of China (English)

    孟令媛; 史保平

    2012-01-01

    The 4 April 2010 Mw7. 2 Baja, Mexico, earthquake occurred in northern Baja California at shallow depth along the principal plate boundary between North American and Pacific plates, and two people were killed in the Mexicalia area. The 14 April 2010 Mw6. 9 Yushu, China, earthquake occurred as a result of strike-slip faulting in tectonically complex region of the eastern Qingzang plateau. At least 2 220 people were killed in Yushu area till April 25, 2010. International media reports of such kind of disasters by Yushu earthquake is resulted from poor building structure design comparing with Mexicalia area. In fact, although the moment magnitude of Yushu event is similar to the Baja event, the radiated seismic energy from Yushu fault dynamic rupture is almost 10 times of the Baja earthquake, resulting stronger near-fault ground motions. In this paper, two special finite fault models with the same size in fault length and width are constructed to simulate the near-fault strong ground motions for comparison study. The fault slip distributions on both faults are generated based on a dynamical composite source model, in which the subevent-source-function is described by Brune's pulse. Our result shows that the near-field peak ground accelerations (PGAs) and peak ground velocities (PGVs) on bed rocks from Yushu event are almost twice as that from Baja event. Moreover, if the shallow velocity structures (V30, average shear-velocity down to 30 m) are considered in the strong motion simulation, the resultant PGAs and PGVs from Yushu event are also twice as that from Baja event. Therefore, the radiated seismic energy plays a significant role in determining the levels of strong ground motions, in which stronger ground accelerations usually cause much more property damages on the ground. The source rupture dynamics related to the frictional overshoot and undershoot is discussed and used to constrain source parameters such as the static stress drop and dynamic stress drop. It

  3. Post subduction thermal regime of the western North America and effects on the Great Valley, Sierra Nevada and northern Baja California provinces

    Science.gov (United States)

    Erkan, Kamil

    the region shows that there is a significant lateral component of the heat flow in to the Sierra Nevada due to Basin and Range province and due to basal heating. The model further suggests that the lateral heating results in considerable thermal uplift at the eastern edge of the Sierra Nevada region. The model is also applicable in the Northern Baja California since this region was part of the same tectonic setting as the Sierra Nevada arc before the inland jump of the San Andreas Fault. The Coast Ranges are interesting with having spots of magmatic and volcanic arc activity likely associated with the cessation of subduction. The third paper is a study related to one of these spots 90 km north of San Francisco, characterized by elevated heat flow in an area of 2500 km2 (The Geysers anomaly). The geothermal system is associated with a very young (˜2 My) bimodal volcanism and magma intrusion at crustal levels. Taking advantage of a sealed, vapor dominated geothermal system due to rocks of very low permeability, forward and inverse models of the deeper magmatic source were constructed. We used extensive heat flow data that were collected over more than 20 years time period. The models revealed that the magmatic source in the Geysers must be as shallow as 7-8 km in order to satisfy the thermal data. Furthermore, the magma system must cover most of the thermally anomalous region. Another type of geothermal system is characterized by rising of hot waters by buoyancy forces without the necessity of a magmatic source at depth. We studied one of these systems in interior Alaska, called Chena Hot Springs, in the fourth paper. The explored system is 1 km long and temperatures are only 74°C. Although the system is moderate in temperature, the low-temperature surface conditions enable the system to be exploited for production of electricity. The geochemical analyses show that the source temperatures are around 121°C. We analyzed the temperature data from 17 exploration wells in

  4. Earthquake cycle on a transform fault in the Gulf of California, Mexico.

    Science.gov (United States)

    Malservisi, Rocco; Hackl, Matthias; Plattner, Christina; Suarez Vidal, Francisco; Gonzales Garcia, Javier; Amelung, Falk

    2010-05-01

    South of the San Andreas Fault system, ~90% of the North America/Pacific plate motion is accommodated along the Gulf of California. Here the plate boundary deformation is partitioned in deep basins formation, often resulting in production of new oceanic crust, connected by long transform faults. In the central part of the Gulf, one of these transform faults, the Ballenas fault, is localized in the Canal de Ballenas, a ~30 km wide channel between Isla Angel de la Garda and mainland Baja California in an area where full oceanic crust is still not generated. The presence of land on both the sides of this "quasi marine" transform fault give the unique opportunity to perform geodetic studies across its trace. On August 3rd 2009, a series of seismic strike slip events (including a M6.9) happened along this segment of plate boundary allowing a combined study of co- and inter-seismic deformation. Here we present the results from 5 years of EGPS along a transect perpendicular to the plate motion direction at approximately 29 degrees North. These surveys include at least 3 occupations before the seismic event and at least 2 occupations after the earthquake. The analysis of the inter-seismic data shows that ~46 mm/yr of relative motion is accommodated within the Canal de Ballenas. Co-seismic data show displacements up to 25 cm on the two sites closest to the event and a pattern compatible with the finite fault model computed by USGS (although the USGS location of the hypocenter is probably 100 km too much to the East). The geodetically estimated fault location is also compatible with multibeam bathymetry. The data collected after the earthquake show also the possibility to identify postseismic displacement from the campaign data. They also show the possibility that the postseismic behavior of the "marine" side is different from the one of the on land side.

  5. 77 FR 36119 - Pistachios Grown in California, Arizona, and New Mexico; Order Amending Marketing Order No. 983

    Science.gov (United States)

    2012-06-18

    ... ] provide an additional tool to aid in the marketing of pistachios covered under the order. In the event the... Agricultural Marketing Service 7 CFR Part 983 Pistachios Grown in California, Arizona, and New Mexico; Order Amending Marketing Order No. 983 AGENCY: Agricultural Marketing Service, USDA. ACTION: Final rule....

  6. A new species of palaemonid shrimp, Chacella tricornuta spec. nov (Crustacea: Decapoda: Palaemonidae) from the southeastern Gulf of California, Mexico

    NARCIS (Netherlands)

    Hendrickx, M.E.

    1990-01-01

    A new species of the palaemonid shrimp genus Chacella Bruce is described from the Gulf of California, Mexico, in the eastern Pacific, and represents the second known species of this genus. The type-species, Chacella kerstitchi (Wicksten, 1983), was described from a single female captured off the coa

  7. Impacto espacial diferenciado en el consumo y adicción a las drogas en la frontera norte de México: el caso del Estado de Baja California

    OpenAIRE

    Pablo Jesús González Reyes

    2011-01-01

    En el artículo se resalta la distribución del uso de drogas en México, destacando el papel de la región del norte, la cual presenta los porcentajes de consumo más altos del país. A un nivel más específico, se abordan las implicaciones individuales y sociales en el abuso del consumo de bebidas alcohólicas entre la población, así como los efectos del ambiente familiar, trayectorias escolares y laborales de los adictos a las drogas ilícitas en Baja California, al igual que las correlaciones esta...

  8. Microstructural and seismic properties of the upper mantle underneath a rifted continental terrane (Baja California): An example of sub-crustal mechanical asthenosphere?

    NARCIS (Netherlands)

    Palasse, L.N.; Vissers, R.L.M.; Paulssen, H.; Basu, A.R.; Drury, M.R.

    2012-01-01

    The Gulf of California rift is a young and active plate boundary that links the San Andreas strike-slip fault system in California to the oceanic spreading system of the East Pacific Rise. The xenolith bearing lavas of the San Quintin volcanic area provide lower crust and upper mantle samples from b

  9. Daily food intake of Kajikia audax (Philippi, 1887 off Cabo San Lucas, Gulf of California, Mexico Tasa de consumo diario de alimento de Kajikia audax (Philippi, 1887 frente a Cabo San Lucas, golfo de California, México

    Directory of Open Access Journals (Sweden)

    Leonardo A Abitia-Cárdenas

    2011-11-01

    Full Text Available The daily food intake rates of the striped marlin, Kajikia audax (Perciformes: Istiophoridae, were estimated using qualitative and quantitative analyses of their trophic spectrum. We analyzed the stomach contents of 505 striped marlin caught by the sport fishing fleet off Cabo San Lucas, Baja California Sur, Mexico, sampled from October 1987 through December 1989. The most important preys were chub mackerel (Scomber japonicus, California pilchard (Sardinops caeruleus, and jumbo squid (Dosidicus gigas; together these represented ~55% of the striped marlin diet. The daily food consumption was estimated to be 2 kg per day, or ~3.6% of the mean body weight of K. audax. The total biomass of the prey consumed by the striped marlin during the 27 months of sampling around Los Cabos was estimated at 24.8 ton, of which the chub mackerel represented ~29% (7.2 ton, California pilchard just under 16% (3.9 ton, and jumbo squid ~10% (2.5 ton. The feeding habits of K. audax are discussed in terms of the distribution of the epipelagic (neritic and oceanic zones, demersal, and benthic prey, confirming that striped marlin migrate vertically and horizontally in search of their food.Se estimó la tasa de consumo diario de alimento del marlín rayado Kajikia audax (Perciformes: Istiophoridae, sobre la base de análisis cualitativos y cuantitativos de su espectro trófico. Se analizó el contenido estomacal de 505 ejemplares capturados por la flota deportiva frente a Cabo San Lucas, Baja California Sur, México muestreados de octubre 1987 a diciembre 1989. Las presas más importantes fueron la macarela del Pacífico (Scomber japonicus, sardina monterrey (Sardinops caeruleus y calamar gigante (Dosidicus gigas, que en conjunto representaron aproximadamente el 55% de la dieta. La tasa de consumo de alimento fue estimado en 2 kg diarios, lo cual representó aproximadamente el 3,6% del peso corporal de K. audax. La biomasa total de presas consumidas por el marlín rayado

  10. Mapping human dimensions of small-scale fisheries in the Northern Gulf of California, Mexico

    Science.gov (United States)

    Moreno-Baez, Marcia

    Recurrent crises due to overexploitation of fishery resources have been among the biggest natural resource management failures of the 20th century. This problem has both biological and socio-political elements and understanding of human dimensions represents a key step toward the formulation of sound management guidelines for natural resources. One of the strategies proposed to understand human dimensions is through the use of local knowledge. Integrating local peoples' knowledge with scientific research and data analysis, could aid in the design of fisheries management strategies in a cost-effective and participatory way. I introduce an approach to incorporating fishers' local knowledge at a large, regional scale. I focused on the spatial and temporal distribution of fishing activities from 17 communities in the Northern Gulf of California, Mexico. Participatory mapping (maps produced by local fishers) through a rapid appraisal (survey methodology) were used to identify the spatial and temporal dimensions of fishing activities. A geographic information system was used to generate 764 map layers used for a preliminary analysis of rapid-appraisal spatial data. Post-survey workshops with fishers were organized to facilitate an internal validation of spatial information using geographic information system software. We characterized the information based on fishing communities, fishing methods, target species and spawning sites. We also applied spatial analysis techniques to understand the relative importance and use of fishing grounds, fishing seasons and the influence that fishing communities have over the region. This dissertation addressed the problem of integrating the human dimensions of small-scale fisheries using geospatial tools and local knowledge (LK) -- data collection, integration, internal validation, analysis and access -- into a multidisciplinary research to support decision making in natural resource planning for small-scale fisheries management and

  11. Geodatabase of the available top and bottom surface datasets that represent the Basin and Range basin-fill aquifers, Arizona, California, Idaho, Nevada, New Mexico, Oregon, and Utah

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This geodatabase includes spatial datasets that represent the Basin and Range basin-fill aquifers in the States of Arizona, California, Idaho, Nevada, New Mexico,...

  12. San Juanico, BCS, Mexico, hybrid electric plant renewable energies in the rural communities development; Planta electrica hibrida San Juanico, B.C.S., Mexico, las energias renovables en el desarrollo de las comunidades rurales

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Rios, Serafin [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad (Mexico)

    1999-08-01

    The hybrid electric plant of San Juanico, B.C.S., Mexico, is described in terms of its environmental goals, operating process and contribution to the development of that rural community of the Baja California Peninsula. San Juanico hybrid electric plant is organized in three electrical generation systems that work in parallel: one uses solar energy, another wind energy and a third one uses diesel fuel. [Spanish] Se describe la planta hibrida de San Juanico, BCS, Mexico, en terminos de los objetivos ambientales que condujeron a su realizacion, asi como de su proceso operativo y de la participacion que tiene en el desarrollo de esa comunidad rural de la peninsula de Baja California, Mexico. La planta hibrida de San Juanico esta constituida por tres sistemas de generacion de electrcicidad que operan en paralelo: uno utiliza energia radiante del sol, otro energia del viento y un tercero utiliza diesel.

  13. Nutrient and temperature controls on modern carbonate production: An example from the Gulf of California, Mexico

    Science.gov (United States)

    Halfar, Jochen; Godinez-Orta, Lucio; Mutti, Maria; Valdez-Holguín, José E.; Borges, Jose M.

    2004-03-01

    In addition to salinity and temperature, nutrient concentrations in surface waters are known to have a significant impact on distribution of carbonate-producing biota, but have never been quantitatively evaluated against different temperatures along a latitudinal transect. The western coast of the Gulf of California, Mexico, presents a natural laboratory for investigating the influence of oceanographic parameters such as salinity, temperature, and chlorophyll a, a proxy for nutrients, on the composition of a range of modern heterozoan and photozoan carbonate environments along a north-south latitudinal gradient spanning the entire warm-temperate realm (29°N 23°N). Chlorophyll a, measured in situ at half-hour resolution, is highly variable throughout the year due to short-term upwelling, and increases significantly from the southern to northern Gulf of California. Salinity, in contrast, fluctuates little and remains at an average of 35‰. From south to north, carbonate production ranges from oligotrophic-mesotrophic, coral reef dominated shallow-water areas (minimum temperature 18.6 °C) through mesotrophic-eutrophic, red algal dominated, inner-shelf carbonate production in the central gulf (minimum temperature 16 °C), and to molluscan-bryozoan, eutrophic inner- to outer-shelf environments (minimum temperature 13.7 °C). The Gulf of California data, supplemented with oceanographic and compositional information from a database compiled from a spectrum of modern carbonate systems worldwide, demonstrates the significance of nutrient control in the formation of heterozoan, photozoan, and transitional heterozoan-photozoan carbonate systems and serves as a basis for more accurately interpreting fossil carbonates.

  14. Methodology to determine the consumption and potential of saving of electrical energy in the systems of air-conditioning in the residential sector: case the Northwest of Mexico; Metodologia para determinar el consumo y potencial de ahorro de energia electrica en los sistemas de climatizacion en el sector residencial: caso Noroeste de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Rosas Flores, J. A.; Morillon Galvez, D.

    2008-07-01

    In this work there are studied the characteristics of the consumption of electrical residential energy due to the systems of air conditioning and to cos mell, in the region Northwest of Mexico (Sonora, Sinaloa, Baja California Norte, Baja California Sur, and Nayarit) and the North region (Coahuila, Chihuahua, Durango, Nuevo Leon). Between the principal results one finds that the potential saving of electrical energy, with base in the use of passive systems as the isolation of the housings, decided in 3,356 GWh (similar to the electrical annual supply that there needs the state of Durango or Guerrero). (Author)

  15. Juventud, readaptación y sueños truncados: Centro de Diagnóstico para Adolescentes de Tijuana, Baja California

    Directory of Open Access Journals (Sweden)

    María Ruth Velázquez Gutiérrez

    2015-01-01

    Full Text Available la violencia no es un problema de pobreza o marginación; se vincula al deterioro de condi-ciones de vida, desintegración familiar y bajas expectativas de adolescentes y jóvenes en elfuturo.este abandono los orilla a conductas antisociales tipificadas en delincuencia juvenily su reclusión en el sistema penitenciario entijuana.el estudio sitúa en perspectiva las me-didas instrumentadas en elcentro de Diagnóstico paraadolescentes detijuana y sugierecambios en las prácticas de reinserción, por lo menos en lo educativo.el ejercicio se apoya enentrevistas con adolescentes recluidos para entender y explicar mejor este fenómeno.

  16. Avifauna de la selva baja caducifolia en la cañada del río Sabino, Oaxaca, México Avifauna of the tropical dry forest in the Sabino Canyon, Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Leopoldo Vázquez

    2009-08-01

    Full Text Available Se describe la avifauna de la selva baja caducifolia del cañón del río Sabino, Oaxaca, al sureste de la Reserva de la Biosfera Tehuacán-Cuicatlán y compara la similitud de la avifauna de la Reserva con la de otras regiones con selvas bajas en México. El trabajo se realizó entre junio de 2005 y octubre de 2006, registrando 113 especies pertenecientes a 13 órdenes y 34 familias; 6 especies son muy abundantes, 10 abundantes, 20 comunes, 32 poco comunes y 37 raras; 79 de las especies registradas fueron residentes, 28 visitantes invernales, 2 visitantes de verano, 3 transitorias y 5 residentes con movimientos estacionales; 15 especies son endémicas a México y 23 están dentro de alguna categoría de riesgo. La avifauna estudiada representa una mezcla de especies características de la cuenca del Balsas, las vertientes pacífica y atlántica y los ambientes montanos y áridos del centro de México. Por su composición específica la avifauna estudiada se relacionó con las avifaunas de la cuenca del Balsas. La selva baja del cañón del Sabino es prioritaria para la conservación debido a su riqueza en especies endémicas y a la presencia una colonia reproductora de la guacamaya verde, Ara militaris, especie globalmente amenazada.This study describes the birds of the tropical dry forest in Sabino Canyon, Oaxaca, in the southeastern part of the Tehuacán-Cuicatlán biosphere reserve. Field work was conducted between June 2005 and October 2006. A total of 113 species belonging to 13 orders and 34 families were recorded. Six species were classified as very abundant, 10 as abundant, 20 as common, 32 as uncommon, and 37 as rare; 79 species were permanent residents, 28 were winter visitors, 2 summer visitors, 3 transients, and 5 were local migrants; 15 species were classified as endemic to Mexico, and 23 are threatened. The bird composition of Sabino Canyon mainly resembles the avifauna the Balsas river basin. The avifauna of the tropical dry

  17. 76 FR 67792 - Additional Designations, Foreign Narcotics Kingpin Designation Act

    Science.gov (United States)

    2011-11-02

    ... Bernardino, Colombia; Iguala, Guerrero, Mexico; Ensenada, Baja California, Mexico; Mexicali, Baja California... Costa Bella, Ensenada, Baja California, Mexico; (ENTITY) 2. AUTODROMO CULIACAN RACE PARK, Blvd. Universitarios No. 196 Ote., Piso 4, Colonia Tierra Blanca, Culiacan, Sinaloa, Mexico; Carretera Libre,...

  18. Mexico.

    Science.gov (United States)

    Semaan, Leslie

    The text explores Mexico's history, geography, art, religion, and lifestyles in the context of its complex economy. The text focuses on Mexico's economy and reasons for its current situation. Part I of this teaching unit includes: Teacher Overview, Why Study Mexico, Mexico Fact Sheet, Map of Mexico, the Land and Climate, History, Government,…

  19. Origen y distribución de la ictiofauna de la Laguna de San Ignacio, Baja California Sur, México

    OpenAIRE

    2000-01-01

    San Ignacio Lagoon is a coastal lagoon in the west coast of Mexico that belongs to the largest protected area of the country: El Vizcaino Biosphere Reserve. Despite the outstanding ecological, bio-economical and landscape features of the zone, management of its resources is absent because there are few studies about them. The ichthyofauna has been studied to an alpha taxonomic level, but the icthhyological resources have several fields to be studied. The present work reviews the geological hi...

  20. Public Outreach and Educational Experiences in Mexico and Latin American communities in California

    Science.gov (United States)

    Andres De Leo-Winkler, Mario; Canalizo, Gabriela; Pichardo, Barbara; Arias, Brenda

    2015-08-01

    I have created and applied diverse methods in public outreach at National Autonomous Univerisity of Mexico (UNAM) since 2001.A student-led volunteer astronomical club has been created, the biggest in Mexico. We serve over 10,000 people per year. We have created public outreach activities for the general audience: archeo-astronomical outings, scientific movie debates, conferences, courses, public telescope viewings. We have also worked with juvenile delinquents to offer them scientific opportunities when released from jail.I've also created and worked the social media for the Institute of Astronomy UNAM, which is currently the biggest social media site on astronomy in Spanish in the world. I've created and organized a mass photo exhibition (over 1 million people served) for the Institute of Astronomy, UNAM which was citizen-funded through an online platform, the first of its kind in the country. Together with my colleages, we created workshops on astronomy for children with the Mexican's government funding.I've participated in several radio and television programs/capsules designed to bring astronomy to the general audience, one in particular ("Astrophysics for Dummies") was very successful in nation-wide Mexican radio.I am currently applying all experiences to develop a new public outreach project on astronomy for the University of California - Riverside and its on-campus and surrounding Latin American communities. We are offering new workshops for blind and deaf children. We want to integrate the Latino community to our outreach activities and offer science in their language in a simple and entertaining fashion. We have also successfully applied astrophotography as a course which brings social-science and arts undergraduate students into natural sciences.Sharing experiences, success and failure stories will help new and experienced educators and public outreach professionals learn and better from past experiences.

  1. Fetal mummification in silky shark (Carcharhinus falciformis from the Gulf of California, Mexico

    Directory of Open Access Journals (Sweden)

    Jonathan Sandoval-Castillo

    2008-06-01

    Full Text Available The aim of this work was the description of fetal mummification in silky shark. During July of 2001 in Santa Maria fishing camp, Gulf of California Mexico, fourteen pregnant female of silky sharks were captured. In all of them the embryos were found to be dehydrated. However, total observations were possible in only two litters. Six embryos in each analyzed litters were found. All the embryos were mummified, complete and without maceration. Because the litters were totally mummificated in several females, it was suggested that fetal mummification was produced by the environmental condition.A mumificação fetal é caracterizada pela desidatração de embriões mortos dentro do útero da mãe. A perda de embriões pode afetar a sustentabilidade da população explorada, tornando o estudo deste fenômeno de suma importância. Em Julho de 2001 quatorze femeas grávidas do tubarão lombo preto foram capituradas durante uma amostragem no campo pesqueiro de Santa Maria, Golfo de California, México. Todas as fêmeas capturadas apresentaram embriões mumificados. Infelizmente, observações detalhadas dos embriões foram possíveis em apenas duas fêmeas. Cada fêmea analizada apresentava seis embriões, todos completamente mumificados e sem maceração. Embriões completamente mumificados foram encontrados em muitas fêmeas, o que sugere que a mumificação fetal desses embriões pode ter sido causada por condições ambientais.

  2. Daño genético y exposición a plaguicidas en trabajadores agrícolas del Valle de San Quintín, Baja California, México Genetic damage and exposure to pesticides among agricultural workers from Valle de San Quintín, Baja California, México Danos genéticos e exposição a pesticidas em trabalhadores agrícolas do Vale San Quintin, Baixa California, México

    Directory of Open Access Journals (Sweden)

    J. Claudia Leyva Aguilera

    2012-12-01

    Full Text Available Diferentes estudios muestran la capacidad de los plaguicidas para inducir daño genético (DG con diversos efectos en la salud. En el presente trabajo se estudia la genotoxicidad en residentes del valle agrícola de San Quintín, Baja California, México (VSQ. El objetivo fue determinar si la exposición laboral y ambiental a plaguicidas en la región del VSQ es un factor de DG y explorar si las mujeres son más vulnerables a dicho efecto. Se aplicó un cuestionario a 88 residentes del VSQ para determinar los factores de inclusión y exclusión del estudio, 40 aceptaron participar, 25 expuestos ocupacionalmente a plaguicidas y 15 ambientalmente expuestos, con similar número de hombres y mujeres. Todos los participantes firmaron un consentimiento informado. Se utilizó la técnica de micronúcleos (MN por bloqueo de la citocinesis en sangre periférica para evaluar el DG con la frecuencia de MN y Puentes de Cromatina en 1000 células binucleadas (CBN; se exploró la correlación del DG con el tiempo de exposición ocupacional a plaguicidas. Los hombres ambientalmente expuestos tuvieron menos DG que las mujeres con medias de MN de 8,1 (±1,83 y 13,1 (±1,7 respectivamente; en cambio, la exposición laboral afectó a los dos sexos: los hombres tuvieron una media de MN igual a 15,9 (±2,9 y en las mujeres fue 18,1 (±1,7. Se concluye que la exposición laboral a plaguicidas es un factor de DG, las mujeres mostraron mayor vulnerabilidad al DG. El tiempo de exposición laboral se relaciona directamente con el aumento del número de MN.Various studies have shown the ability of pesticides to induce genetic damage (GD that can cause health effects. In the present work, a genotoxicological study was conducted monitoring residents from the agricultural region of the San Quintin Valley (SQV, Baja California, Mexico. The objective was to determine if occupational and environmental exposure to pesticides in the region of the SQV is a factor in GD, and to

  3. Source Functions and Path Effects from Earthquakes in the Farallon Transform Fault Region, Gulf of California, Mexico that Occurred on October 2013

    Science.gov (United States)

    Castro, Raúl R.; Stock, Joann M.; Hauksson, Egill; Clayton, Robert W.

    2016-07-01

    We determined source spectral functions, Q and site effects using regional records of body waves from the October 19, 2013 (M w = 6.6) earthquake and eight aftershocks located 90 km east of Loreto, Baja California Sur, Mexico. We also analyzed records from a foreshock with magnitude 3.3 that occurred 47 days before the mainshock. The epicenters of this sequence are located in the south-central region of the Gulf of California (GoC) near and on the Farallon transform fault. This is one of the most active regions of the GoC, where most of the large earthquakes have strike-slip mechanisms. Based on the distribution of the aftershocks, the rupture propagated northwest with a rupture length of approximately 27 km. We calculated 3-component P- and S-wave spectra from ten events recorded by eleven stations of the Broadband Seismological Network of the GoC (RESBAN). These stations are located around the GoC and provide good azimuthal coverage (the average station gap is 39°). The spectral records were corrected for site effects, which were estimated calculating average spectral ratios between horizontal and vertical components (HVSR method). The site-corrected spectra were then inverted to determine the source functions and to estimate the attenuation quality factor Q. The values of Q resulting from the spectral inversion can be approximated by the relations Q_{P} = 48.1 ± 1.1 f^{0.88 ± 0.04} and Q_{S} = 135.4 ± 1.1 f^{0.58 ± 0.03} and are consistent with previous estimates reported by Vidales-Basurto et al. (Bull Seism Soc Am 104:2027-2042, 2014) for the south-central GoC. The stress drop estimates, obtained using the ω2 model, are below 1.7 MPa, with the highest stress drops determined for the mainshock and the aftershocks located in the ridge zone. We used the values of Q obtained to recalculate source and site effects with a different spectral inversion scheme. We found that sites with low S-wave amplification also tend to have low P-wave amplification, except

  4. Diagnóstico de conocimiento, actitudes y estrategias de equidad de género en servidoras y servidores públicos de primer nivel en Baja California

    Directory of Open Access Journals (Sweden)

    Elizabeth Maier

    2011-01-01

    Full Text Available El presente artículo se basa en el Diagnóstico de conocimientos, actitudes y estrategias de equidad de género de funcionarias y funcionarios de primer nivel en Baja California, estudio cuyo objetivo fue evaluar los conocimientos y las receptividades o resistencias de servidoras y servidores públicos bajacalifornianos sobre la equidad de género; así mismo, se aprecia la transversalidad de la aplicación de la perspectiva de género como guía metodológica de su ejercicio de políticas públicas. La hipótesis implícita al estudio insiste en la necesidad de contar con estrategias de progresiva capacitación en la temática para promover la creciente desautorización del complejo enjambre cultural de inequidad de género que todavía define el acceso diferencial a las oportunidades y beneficios económicos, sociales y políticos en el estado.

  5. La academia y el sector productivo en Baja California. Los actores y su capacidad de vinculación para la producción, difusión y trasferencia del conocimiento y la innovación

    Directory of Open Access Journals (Sweden)

    Minerva Celaya Tentori

    2012-01-01

    Full Text Available En el artículo se analizan las capacidades de vinculación de las instituciones de educación superior y los centros científicos de Baja California con el sector productivo, enfocadas a incentivar los procesos de producción, difundir y trasferir conocimiento, promover la innovación, así como generar la competitividad de las empresas ahí localizadas. Se parte de la perspectiva teórica de Edith Penrose (1980 sobre el llamado resource-based view, donde las capacidades y recursos son elementos esenciales para el desarrollo de las empresas en una región, ya que funcionan como base para apropiar, sistematizar, divulgar y aplicar conocimiento científico nuevo, y así generar innovación. Se busca identificar las condiciones que permiten que la cooperación entre las empresas y las universidades se produzca de manera regular, formal y continua. Para la operacionalización de esta teoría, las autoras se apoyan en el trabajo realizado por Araya y Chaparro (2005 sobre las capacidades de vinculación de instituciones educativas en Chile.

  6. ¿Por qué son mejores los organismos de agua de Baja California que los de Sonora? Instituciones locales y desempeño de los organismos públicos

    Directory of Open Access Journals (Sweden)

    Nicolás Pineda Pablos

    2012-01-01

    Full Text Available El desempeño de los principales organismos operadores de agua para uso urbano de Baja California, a juzgar por los indicadores de gestión, es superior al de los de Sonora. El objetivo de este artículo es compararlos, y reflexionar sobre las variables explicativas de dicha diferencia. Los dos estados tienen características geográficas y demográficas similares: son fronterizos, su clima es semidesértico y su población comparte la misma cultura y comportamientos. El estudio indaga las causas, y revisa las reglas institucionales que pueden explicar el desempeño diferenciado: la instancia gubernamental responsable del servicio, la duración de los directores, la tarifa, facturación y cobranza, así como la alternancia de partido político en el gobierno local y aquél del cual han emanado los gobiernos responsables del servicio. El estudio concluye que las instituciones importan, y que sus reglas han hecho la diferencia en el desempeño de los organismos de agua de ambas entidades.

  7. The Southern Baja - Islas Marías - Sinaloa Transect: What is common? What was moving?

    Science.gov (United States)

    Schaaf, P. E.; Perez-Venzor, J.; Solis, G.; Hernandez, T.; Arrieta, G. F.; Pompa, V.; Villanueva, D.

    2013-12-01

    The Gulf of California extensional province constitutes an issue of ongoing multidiscipline investigations. It is considered as a result of late Miocene to Pliocene faulting and 'Comondu-type' magmatism related to Pacific-North America plate boundary motions. Transtensional faulting has rifted Baja California obliquely away from mainland Mexico over the past 12 Ma. To understand these processes and to reconstruct transportation distances, it is helpful to look back into the past. In this contribution we present a V-shaped lithological and geochronological profile, starting from the Los Cabos Block, Baja California Sur to the west, passing southerly Islas Marias Islands in the mouth of the Gulf and ending in south-central Sinaloa (Mazatlan region) to the east. All three locations display 80 Ma plutonic rocks of granodioritic to tonalitic compositions with similar Sr and Nd isotope signatures. Voluminous to minor shaped early Cretaceous gabbro outcrops are found south of La Paz (Novillo Massif) and ca. 30 km N of Mazatlan. The basement of the three sites is composed of 160-170 Ma (+/- migmatitic) orthogneisses, covered by schists and paragneisses with detrital zircon peaks at ca. 260, 520, and 1000 Ma. Abundant calc-silicates are found in the southern Los Cabos Block as well as on Maria Madre Island. Sandstones and shales from Islas Marias can be divided into two units with minimum detrital zircon ages of 80 Ma and 21 Ma, respectively. The micropaleontological record in these sediments indicates repeated uplift and subsidence events, related to the opening of the Gulf of California. In Maria Magdalena island, the sedimentary sequence is intruded in sills by Islas Marias rock units give strong evidence for their common and continuous magmatic and metamorphic evolution and confirm a 400-450 km NW displacement of southern Baja. Larger offsets are difficult to constrain from geological and paleomagnetic data. Southern Baja granitoids belong to the Cordilleran batholitic

  8. Hidrografía en la Boca Norte de la Bahía de La Paz, Baja California Sur, México

    OpenAIRE

    Obeso-Nieblas Obeso-Niebla; B Shirasago-Germán; JH Gaviño-Rodríguez; H Obeso-Huerta; EL Pérez-Lezama; AR Jiménez-Illescas

    2007-01-01

    Con el objetivo de describir la variabilidad hidrográfica en la principal comunicación de la Bahía de La Paz con el Golfo deCalifornia, llamada Boca Norte, se analizaron datos de CTD de cuatro campañas de muestreo realizadas durante un ciclo anual(mayo, julio y octubre de 2001, así como febrero de 2002). Los resultados muestran en la primavera y el verano una ausencia deuna capa de mezcla, con una intensa estratificación de temperatura y salinidad, mientras que en el otoño se registró una cap...

  9. Parliamentary set-up and productivity within Baja California’s Congress

    Directory of Open Access Journals (Sweden)

    Cuauhtémoc López Guzmán

    2002-07-01

    Full Text Available This document presents a static and dynamic analysis of the Congress of Baja California, Mexico. The static portion encompasses the historic origin of the congress, its constitutional functions, and partisan composition.The dynamic section is a comparative study of the legislative productivity during two periods: the period of a unified government (1953-1989, and the period of a divided government (1989-2001. Additionally, metrics are constructed to analyze the parliamentary dynamics under a divided majority format with the purpose of rationalizing the institutional, political, and partisan conditions that create, between the executive and legislative powers, an environment of cooperation and conflict that affects the yeild of the institution and democracy.

  10. Effectiveness of bats as pollinators of Stenocereus stellatus (Cactaceae) in wild, managed in situ, and cultivated populations in La Mixteca Baja, central Mexico.

    Science.gov (United States)

    Arias-Cóyotl, Ethel; Stoner, Kathryn E; Casas, Alejandro

    2006-11-01

    Stenocereus stellatus is an endemic, self-incompatible, columnar cactus found in central Mexico where many of its wild populations have been fragmented. As an economically important species of fruit-producing cactus, S. stellatus occurs in wild, managed in situ, and cultivated populations. The objectives of this study were to determine the effective pollinators of S. stellatus, to compare pollinator visits and reproductive parameters among the three types of populations, and to determine if nectar feeding-bats are moving among populations. Effective pollinators were the nectarivorous bats Choeronycteris mexicana, Leptonycteris curasoae, and L. nivalis. Fewer total visits per flower per night and fewer visits by Choeronycteris were observed in cultivated populations, while the opposite pattern was observed for Leptonycteris. One aggressive interaction was filmed in which Choeronycteris was physically displaced by Leptonycteris, and Choeronycteris visits were significantly affected by Leptonycteris visits. Cultivated populations received more pollen grains and had more fruit set. Variation in pollinator visits between different populations and the consequent effects on reproductive success were likely a result of competition between bat species, and differences in foraging and in sensitivity of bat species to human populations. Three marked L. curasoae traveled 15 km from their roosting site to their foraging area, and one visited cultivated and managed populations, suggesting that this species may be particularly important in moving pollen among populations.

  11. First assessment of low- to medium-temperature geothermal reserves in 20 Mexican states; Primera estimacion de las reservas geotermicas de temperatura intermedia a baja en veinte estados de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, Eduardo R.; Torres, Rodolfo J. [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: iglesias@iie.org.mx

    2009-07-15

    A first, partial, assessment is included of the low- to medium-temperature geothermal reserves in 20 Mexican States and their aggregate value. The assessment covers about 29.16% of the identified geothermal-surface manifestations in the public database. For reserve assessments, we use the volumetric method, supplemented with Montecarlo simulations and statistics, to quantify inherent uncertainties. Our estimations are presented on a state-by-state basis. We estimate the aggregated reserves of the 20 states as between 7.7 x 1016 and 8.6 x 1016 kJ, with 90% confidence. The most likely reservoir temperatures range between 60-180 degrees Celsius, with a mean of 111 degrees Celsius. Such massive amounts of recoverable energy-and the associated temperatures-are potentially important for the economic development of nearby localities and the nation. [Spanish] En este trabajo se hace una primera estimacion, parcial, de las reservas geotermicas de temperatura intermedia a baja de Mexico. La estimacion incluye 29.16% de las manifestaciones geotermicas identificadas en la base de datos publica utilizada. Para estimar las reservas se utilizo el metodo de volumen, suplementado con simulaciones por el metodo de Montecarlo, con el fin de cuantificar las incertidumbres inherentes. Las estimaciones se presentan estado por estado. Estos resultados indican que las reservas agregadas de los 20 estados considerados estan entre 7.7 x 1016 y 8.6 x 1016 kJ, con 90% de confianza. La distribucion de las temperaturas de yacimiento mas probables varia entre aproximadamente 60 y 180 grados centigrados, con un valor medio de 111 grados centigrados. La enorme magnitud de estas reservas, y sus temperaturas asociadas, son potencialmente importantes para el desarrollo economico de las poblaciones ubicadas en su cercania.

  12. Capacidad de carga turÍstica como base para el manejo sustentable de actividades ecoturísticas en Unidades de Manejo Ambiental (UMA de Baja California Sur (BCS

    Directory of Open Access Journals (Sweden)

    Reyna Ibañez Pérez

    2016-01-01

    Full Text Available Existen zonas ejidales con UMA ́s, que desean incursionar en el turismo alternativo; tal es el caso del Nuevo Centro Poblacional Ejidal (NCPE, Ley Federal de Aguas Número 3, que se extiende a tres municipios de Baja California Sur (BCS, posee una UMA y se destaca por buscar opciones para reactivar su economía. En este trabajo se presentan los resultados de un estudio de Capacidad de Carga Turística (CCT, realizada en dos senderos de ese ejido, mediante la aplicación de la metodología de Cifuentes, que busca establecer el número máximo de visitas que puede recibir un área con base en sus condiciones físicas, biológicas y de manejo; cuya estimación, requirió de la revisión de censos de flora y fauna, de información geológica, climatológica, geográfica, ambiental, social, económica, turística, así como trabajo de campo. Los resultados indican que, en el NCPE, Ley Federal de Aguas Número 3, existen dos senderos con potencialidad turística para los cuales, se ha estimado una Capacidad de Carga Efectiva (CCE de 18 visitantes/día para el sendero del arroyo El Camarón y de 10 visitantes/día sendero del arroyo El Saucito. Las cifras anteriores, son un referente para el establecimiento de medidas de control de las visitas en ambos senderos

  13. Crecimiento económico, desarrollo sustentable y turismo: Una aproximación del posicionamiento de Baja California Sur (BCS en el Barómetro de Sustentabilidad

    Directory of Open Access Journals (Sweden)

    Reyna Ibáñez Pérez

    2011-01-01

    Full Text Available Uno de los mayores anhelos de toda sociedad es alcanzar un nivel económico elevado; otro es el de tener la oportunidad de disfrutar eternamente de los servicios proporcionados por la madre naturaleza. Sin embargo, las tendencias indican que se experimenta un deterioro importante en el ambiente, a la par, de una elevada concentración de pobreza. Esto, aunado a la dependencia que algunas entidades y países han desarrollado en relación a actividades -como la turística- se ha convertido en una de las preocupaciones centrales de los gobiernos, el establecer mediciones para determinar si las pautas de crecimiento y desarrollo, van acorde con el cuidado del ambiente y el bienestar de las personas. Por ello, dentro de este artículo se analizan la evolución del crecimiento económico y posicionamiento de Baja California Sur (BCS -un estado con importante actividad turística- en el Barómetro de Sustentabilidad. En la introducción, se aprecia la evolución del concepto de crecimiento y desarrollo, para continuar con la caracterización de la zona de estudio. Posteriormente, se detalla la metodología empleada. Enseguida, se estudia la situación actual del sector turístico en BCS y la evolución del crecimiento y desarrollo económico. En el análisis de resultados, se describen los factores que ubican a BCS en un nivel Medio de sustentabilidad. Finalmente, se presentan algunas reflexiones en relación a los retos que en materia de turismo, crecimiento económico, desarrollo sustentable afronta BCS.

  14. Composición espacial y temporal de la avifauna de humedales pequeños costeros y hábitat adyacentes en el noroeste de Baja California, México

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Se determinó la composición espacio-temporal de la avifauna en 13 humedales pequeños costeros del noroeste de Baja California entre febrero y diciembre de 2002. Se registraron 17,978 individuos pertenecientes a 187 especies, 121 géneros y 47 familias. Las familias con mayor número de especies fueron Anatidae (17, Scolopacidae (17 y Laridae (12. Los humedales con mayor riqueza específica fueron El Rosario (126, Santo Tomás (107 y La Misión (95, los cuales en conjunto incluyeron al 86% del total de especies observadas. Setenta y seis especies (41% fueron residentes permanentes, 73 (39% visitantes estacionales, y 38 (20% visitantes ocasionales. Con base en la presencia o ausencia de las especies se distinguen cuatro grupos de humedales: (a San Simón, (b La Salina, (c El Descanso-El Ciprés y (d un grupo de nueve sitios que está subdividido en dos ramas de cuatro y cinco localidades, respectivamente: (d.1 San Telmo-Santo Tomás-El Rosario-La Misión y (d.2 San Rafael-San Miguel- El Salado-Santo Domingo-Cantamar. La presencia o ausencia de un cuerpo de agua permanente, los tipos de hábitat y la presencia o ausencia de influencia antropogénica en cada localidad fueron los factores que contribuyeron al agrupamiento de estos humedales. La riqueza y abundancia de especies estuvieron correlacionadas con la diversidad de hábitats. Se documentaron evidencias de reproducción para 20 especies.

  15. Aircraft Regional-Scale Flux Measurements over Complex Landscapes of Mangroves, Desert, and Marine Ecosystems of Magdalena Bay, Mexico

    OpenAIRE

    2013-01-01

    Natural ecosystems are rarely structurally simple or functionally homogeneous. This is true for the complex coastal region of Magdalena Bay, Baja California Sur, Mexico, where the spatial variability in ecosystem fluxes from the Pacific coastal ocean, eutrophic lagoon, mangroves, and desert were studied. The Sky Arrow 650TCN environmental research aircraft proved to be an effective tool in characterizing land–atmosphere fluxes of energy, CO2, and water vapor across a heterogeneous landscape a...

  16. Regional location of electric-electronics sector in Mexico

    Directory of Open Access Journals (Sweden)

    Adán Jacinto Flores Flores

    2016-10-01

    Full Text Available The purpose of this study is to measure the degree of regional location of the electric-electronic sector of Mexico. Location coefficient was calculated using variables total employed persons and the total gross output; It was complemented by a shift-share analysis; both methods based on official information from economic censuses of 2004 and 2009. The methods used is descriptive techniques and the results generated depend on the selected period of time, they suggested that the electric-electronic sector is highly localized in the northeastern regions and northwestern Mexico, more specifically, in the states of Baja California, Chihuahua and Tamaulipas. However, the state of Baja California Sur has a zero activity in the electric-electronic sector. These findings provide support for the development of targeted policies to actions that promote the competitiveness of high-tech industry of Mexico. A future line of research is to expand the scope of the study to identify the most significant conditions for the electric-electronic sector of Mexico location.

  17. Research and technological development on heat pumps in Mexico operating with geothermal energy; Investigacion y desarrollo tecnologico sobre bombas de calor en Mexico operando con energia geotermica

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, Alfonso; Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2008-07-01

    The Instituto de Investigaciones Electricas (IIE) and the Comision Federal de Electricidad (CFE) carried out in the past an extensive work of research and development (R&D) on heat pumps (HP). The systems tried on include heat pumps by mechanical compression, thermal absorption and thermal transformers. This paper briefly describes the main aspects of R&D on heat pumps and presents a more detailed description of three of the main studies: a) a Heat Pump (HP) by mechanical compression water-water type, designed for brine purification, operating with low pressure geothermal steam at the geothermal field Los Azufres, Michoacan, Mexico; b) a HP by absorption for cooling and refrigeration, operating with ammoniac/water and low enthalpy geothermal energy, which was tested in the geothermal fields of Los Azufres, Michoacan and Cerro Prieto, Baja California, and c) a thermal transformer by absorption, named Heat Pump by Absorption Type 2, which was tested to evaluate the behavior of diverse ternary solutions as working fluids. To date, there are plans to install and test a geothermal heat pump (connected to the subsoil), in Cerro Prieto, Mexicali, Baja California, Mexico. [Spanish] El Instituto de Investigaciones Electricas (IIE) y la Comision Federal de Electricidad (CFE) realizaron un trabajo extenso de investigacion y desarrollo (I&D) sobre bombas de calor (BC) en el pasado. Los sistemas que se probaron incluyen bombas de calor por compresion mecanica, absorcion y transformadores termicos. Este trabajo describe brevemente los principales aspectos de I&D sobre bombas de calor y se da una descripcion mas detallada de tres de los principales estudios: a) una Bomba de Calor (BC) por compresion mecanica tipo agua-agua, disenada para purificacion de salmueras, operando con vapor geotermico de baja presion en el campo geotermico de Los Azufres, Michoacan; b) una BC por absorcion para enfriamiento y refrigeracion, operando con amoniaco/agua y energia geotermica de baja entalpia

  18. Análisis de la sequía y desertificación mediante índices de aridez y estimación de la brecha hídrica en Baja California Sur, noroeste de México

    Directory of Open Access Journals (Sweden)

    Enrique Troyo Diéguez

    2014-01-01

    Full Text Available In Baja California Sur ( BCS , Mexico, dry-semi warm and warm climates prevail associated to an extreme trend of diurnal temperatures and the environmental dry-ness. In this State, the maximum summer t exceeds 40° C and the minimum varies from 5 to 12° C, with a minimal for the State of 2° C in winter, at the top of the Sierra de La Laguna; only Los Cabos region has a warm humid climate. Because precipitation in the state is low, oscillating from 310 mm in the southern area of the state to 120 mm per year in the northern portion, predictions and scenarios under climate conditions point to an intensification of droughts. The aim of this work was to carry out a comparative analysis of trends of temperature, precipitation and hydro-environmental aridity among contrasting localities of BCS, by means of the application of Aridity Indexes and the determination of the Standardized Water Gap (BHE, through a numerical scale modification of the De Martonne Index. With the values of temperature and precipitation for the different climate change scenarios for four weather stations, the indicators Hydro Environmental Availability Index (IDHA and Hydro Environmental Drought Index (ISHA were calculated to determine their trend and the consequent BHE , an innovative quantification of water deficit, which is proposed in this paper. The maximum value of BHE (10 units, indicating prevalence of drought, is observed from February to June in almost the entire state. Results suggest that BHE tend to increase and intensify under climate change conditions, which is more evident from the South towards the North of the State. According to the trends of the indexes IDHA, ISHA and BHE, under six scenarios of climatic change for four regions of BCS , BHE can be estimated with a major significance for the region Gustavo Díaz Ordaz-Vizcaíno, Mulegé County, in the North of the State, where may reach a value BHE max = 10 and BHE min = 7.23, values which suggest extreme

  19. Evaluación del impacto socioeconómico de la Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado en la actividad pesquera ribereña de San Felipe, Baja California, México

    Directory of Open Access Journals (Sweden)

    Carlos Israel Vázquez León

    2010-01-01

    Full Text Available Desde 1993 las comunidades de Puerto Peñasco y Golfo de Santa Clara, Sonora, y San Felipe, Baja California, en México, están vinculadas por la Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado; creada para proteger varias especies endémicas, entre ellas al mamífero conocido como vaquita marina (Phocoenasinus y la totoaba (Totoaba macdonaldii.Aquí se analiza el efecto socioeconómico que en la pesca de San Felipe tuvo en 1994 y 2002 la creación de la reserva; concebida como un arreglo institucional de regulación pesquera, centrada en la protección ambiental y ecológica. La conclusión general es que deben incorporarse consideraciones socioeconómicas en el diseño de indicadores de eficiencia y evaluación para el éxito de la reserva territorial.

  20. Hydrochemical-isotopic and hydrogeological conceptual model of the Las Tres Vı´rgenes geothermal field, Baja California Sur, México

    Science.gov (United States)

    Portugal, E.; Birkle, P.; Barragán R, R. M.; Arellano G, V. M.; Tello, E.; Tello, M.

    2000-09-01

    water from the Gulf of California in the deep reservoir. Both conditions indicate recharge of the reservoir by meteoric water during glacial periods in Holocene or Pleistocene time, or a magmatic origin of the reservoir fluids. The slightly positive slope of the δ18O- δD line of geothermal fluids and its intermediate isotopic composition—between the surface samples and magmatic ("andesitic") water indicate that magmatic ("andesitic") water contributes approximately 30% to the geothermal fluid composition, whereas "fossil" meteoric water represents the major component (70%). The geothermal reservoir is considered to represent a hydrostatic, stagnant flow system. Based on the observed linear correlation between the isotopic composition and the altitude of the surface manifestations, the isotopic composition and altitude of the former recharge were determined as δ 18O=-9.7‰ and δ D=-67.3‰, and 350 m.a.s.l., respectively. This altitude is interpreted as mean (average) recharge elevation. Scarcity of permanent rivers, low density of springs and domestic wells, as well as low precipitation rates, reflect restricted distribution of shallow groundwater systems in the study zone. These systems are related to isolated, local aquifers composed of valley fillings.

  1. Organchlorine content and shell thickness in brown booby (Sula leucogaster) eggs in the Gulf of California and the southern Pacific coast of Mexico.

    Science.gov (United States)

    Mellink, Eric; Riojas-López, Mónica E; Luévano-Esparza, Jaime

    2009-07-01

    We determined egg concentrations of organochlorines and thickness of eggshells from brown boobies at eight colonies ranging from the northern Gulf of California to southern Mexico. The only common residue was that of DDE, which was found in almost all eggs. DDE content apparently reflected pre-1990 DDT use in nearby agricultural areas and, at one site, intensive mosquito control for high-end tourism development. There were no inter-colony differences in eggshell thickness, and variation in this variable likely reflected individual bird characteristics and/or individual feeding source. This variable was not a good proxy to DDE exposure of brown boobies, under current DDE levels in the brown booby trophic chain. In the northern Gulf of California, eggshell thickness has recovered to pre-DDT conditions. Our data indicate that the Gulf of California and southwestern coast of Mexico have a healthy near-shore marine environment, as far as organochlorines are concerned.

  2. Environmental impacts of two kind of ponds for shrimp production at Northwest Mexico.

    Science.gov (United States)

    Gonzalez-Ocampo, Hector; Romero-Schmidt, Heidi; Serrano-Pinto, Vania; Arguelles, Cerafina; Salinas, Federico; Rodríguez, Antonio; Castellanos, Aradit; Ortega-Rubio, Alfredo

    2004-01-01

    Aquaculture offers a major opportunity for the economic development of Baja California Sur (BCS), Mexico. The severely limited freshwater supply and the geographic isolation of the state place limits on other productive activities. Despite the aridity, the natural vegetation of BCS is diverse and structurally complex with a high percentage (20%) of endemic species. In this work we compare the environmental impacts produced by two kinds of aquaculture systems: coastal ponds vs. inland ponds. Construction and operation of coastal ponds does not require destruction of the natural vegetation and, as is true for inland ponds. Coastal ponds are also compatible with conservation of mangroves, sea grasses and sensitive habitats for fish and mollusks. To reduce the negative impacts of aquaculture and to protect the vegetation of Baja California Sur, we recommend the use of coastal ponds for shrimp production.

  3. Mexico.

    Science.gov (United States)

    1988-02-01

    Focus in this discussion of Mexico is on the following: geography; the people; history; political conditions; the economy; foreign relations; and relations between the US and Mexico. As of July 1987, the population of Mexico numbered 81.9 million with an estimated annual growth rate of 2.09%. 60% of the population is Indian-Spanish (mestizo), 30% American Indian, 9% white, and 1% other. Mexico is the most populous Spanish-speaking country in the world and the 2nd most populous country in Latin America. Education is decentralized and expanded. Mexico's topography ranges from low desert plains and jungle-like coastal strips to high plateaus and rugged mountains. Hernan Cortes conquered Mexico in 1919-21 and founded a Spanish colony that lasted for almost 300 years. Independence from Spain was proclaimed by Father Miguel Hidalgo on September 16, 1810; the republic was established on December 6, 1822. Mexico's constitution of 1917 provides for a federal republic with a separation of powers into independent executive, legislative, and judicial branches of government. Significant political themes of the administration of President Miguel de la Madrid Hurtado, who began his 6-year term in 1982, have been restructuring the economy, liberalizing trade practices, decentralizing government services, and eliminating corruption among public servants. In 1987, estimates put the real growth of the Mexican economy at 1.5%; the gross domestic product (GDP) had shrunk by 3.5% in 1986. Yet, on the positive side, Mexico's international reserves increased to record levels in 1987 (to about $15 billion), and its current account surplus reached more than $3 billion. Mexico has made considerable progress in moving to restructure its economy. It has substantially reduced impediments to international trade and has moved to reduce the number of parastatal firms. 1987 was the 2nd consecutive year in which Mexico recorded triple-digit inflation; inflation reached 158.8%. Other problems include

  4. Land subsidence in the Cerro Prieto Geothermal Field, Baja California, Mexico, from 1994 to 2005: An integrated analysis of DInSAR, leveling and geological data

    Science.gov (United States)

    Sarychikhina, Olga; Glowacka, Ewa; Mellors, Robert; Vidal, Francisco Suárez

    2011-07-01

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994-1997 and 1997-2006) and detailed geological information in order to improve understanding of the temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the changes in spatial pattern and rate of the subsidence are correlated with the development of the Cerro Prieto Geothermal Field.

  5. The geochemistry and isotope hydrology of the Southern Mexicali Valley in the area of the Cerro Prieto, Baja California (Mexico) geothermal field

    Science.gov (United States)

    Portugal, Enrique; Izquierdo, Georgina; Truesdell, Alfred; Álvarez, Julio

    2005-11-01

    Groundwaters from the phreatic aquifer within and surrounding of the Cerro Prieto geothermal field were analyzed geochemically and isotopically in order to establish a hydrodynamic model of the study zone, which is located in the Mexicali Valley between 655,000-685,000 m E-W and 3,605,000-3,576,000 m N-S relative to UTM coordinates. Based on their chemical composition three types of water were recognized: chloride, sulfate and bicarbonate. However four groups of water were identified on a statistical multi-variable method of cluster analysis (A-D). The average temperature is 25 °C; with a few exceptions in the south where temperature can be as high as 47 °C. Stable isotope ratios for some waters plot close to the world meteoric line, corresponding to the original unaltered waters of the zone. The hydrogeochemistry varies in relation to three principal processes: evaporation, infiltration of water used in agriculture and rock interaction by reaction with evaporitic deposits. Major quartz, calcite and plagioclase and minor smectite, kaolinite, halite, sylvite and gypsum were identified by X-ray diffraction in lacustrine sediments of the central part of the zone. Chemical modeling indicates saturation with respect to calcite and undersaturation with respect to gypsum. By incorporating chemical and isotope data into geological and isopotential well information, a hydrodynamic model has been postulated. In this hydrodynamic model the water (A) enters the study zone from the east and it is originally of the old Colorado River water. The water samples on which the model is based were draw from agricultural wells that intersected two aquifers, a shallow and a deep one, representing the recharge to the zone. The salinity of the deep aquifer water (B) is lower than that of the shallow aquifer water (C) and so is the stable isotope ratio. The difference is though to be due to dissolution of evaporates, evaporation and possible infiltration of spent agriculture water. Both waters then pass through lacustrine sediments and gain in salinity and become isotopically heavier mainly by evaporation in a stagnate flow. They eventually emerge as a saline water (D) in the central part of the study zone. This saline water is the one that mixes with thermal fluid discharges from the geothermal reservoir in the south.

  6. Active metasomatism in the Cerro Prieto geothermal system, Baja California, Mexico: A telescoped low-pressure, low-temperature metamorphic facies series

    Science.gov (United States)

    Schiffman, P.; Elders, W. A.; Williams, A. E.; McDowell, S. D.; Bird, D. K.

    1984-01-01

    In the Cerro Prieto geothermal field, carbonate-cemented, quartzofeldspathic sediments of the Colorado River delta are being actively metasomatized into calc-silicate metamorphic rocks by reaction with alkali chloride brines between 200 and 370 °C, at low fluid and lithostatic pressures and low oxygen fugacities. Our petrologic investigations of drill cores and cuttings from more than 50 wells in this field identified a prograde series of zones that include as index minerals wairakite, epidote, prehnite, and clinopyroxene. Associated divariant mineral assemblages are indicative of a very low pressure, low-temperature metamorphic facies series spanning the clay-carbonate, zeolite, greenschist, and amphibolite facies. This hydro-thermal facies series, which is now recognized in other active geothermal systems, is characterized by temperature-telescoped dehydration and decarbonation. Its equivalent can now be sought in fossil hydrothermal systems.

  7. [Habitat use patterns of the Black Brant Branta bernicla nigricans (Anseriformes: Anatidae) in natural and artificial areas of Guerrero Negro, Baja California Sur, Mexico].

    Science.gov (United States)

    Cedillo, Israel Martínez; Carmona, Roberto; Ward, David H; Danemann, Gustavo D

    2013-06-01

    The Black Brant is a common inhabitant of the Western Artic American tundra, which migrates to Southern Pacific coasts during the winter season. Approximately, 31000 birds (31%) constitute the Mexican population of Brants at Guerrero Negro, Ojo de Liebre, and Exportadora de Sal lagoon complex; nevertheless, there is little information about the distribution patterns and zone usage. At Guerrero Negro Lagoon (GNL), Ojo de Liebre Lagoon (OLL, both natural sites), and at Exportadora de Sal (ESSA, artificial site) we determined by monthly censuses (from November 2006 to April 2007, 08:00-16:00h) and observed: (1) season and site effects on population structure (age groups), and (2) the tide level relationship with the abundance and proportion of feeding birds. Within a total of 150 observation hours and 98 birds, our results showed a general 0.68 proportion of adults, that was higher in winter than in spring. The statistics analysis showed no effects by site on the proportion of feeding birds, but we observed a temporal decrease at ESSA and at GNL. In contrast the proportion of feeding birds at OLL was constant. We observed an increase in the juveniles between winter and spring. This increase is related with the differential migration, which mentions that the juveniles are the last to leave the wintering area. In winter the relations of the tide level with the abundance of Brant were: direct at ESSA, inverse at OLL and no relation found at GNL. In spring, no relation was observed in the sites. The proportion of Brants feeding at OLL (the site with the higher abundance) was independent of the tide level. This is related with two possible behaviors of the geese: (1) they can move through the lagoon and take advantage of the tidal lag, which is up to four hours; and (2) they can modify their feeding strategies, more on floating eelgrass (Zostera marina).

  8. Development of a human-specific B. thetaiotaomicron IMS/ATP assay for measuring viable human contamination in surface waters in Baja California, Mexico

    Science.gov (United States)

    Immunomagnetic separation/adenosine triphosphate (IMS/ATP) assays utilize paramagnetic beads and target-specific antibodies to isolate target organisms. Following isolation, adenosine tri-phosphate (ATP) is extracted from the target population and quantified. An inversely-couple...

  9. Active metasomatism in the Cerro Prieto geothermal system, Baja California, Mexico: a telescoped low-pressure, low-temperature metamorphic facies series

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, P.; Elders, W.A.; Williams, A.E.; McDowell, S.D.; Bird, D.K.

    1984-01-01

    In the Cerro Prieto geothermal field, carbonate-cemented, quartzofeldspathic sediments of the Colorado River delta are being actively metasomatized into calc-silicate metamorphic rocks by reaction with alkali chloride brines between 200 and 370 C, at low fluid and lithostatic pressures and low oxygen fugacities. Their petrologic investigations of drill cores and cuttings from more than 50 wells in this field identified a prograde series of zones that include as index minerals wairakite, epidote, prehnite, and clinopyroxene. Associated divariant mineral assemblages are indicate of a very low pressure, low-temperature metamorphic facies series spanning the clay-carbonate, zeolite, greenschist, and amphibolite facies. This hydrothermal facies series, which is now recognized in other active geothermal systems, is characterized by temperature-telescoped dehydration and decarbonation. Its equivalent can now be sought in fossil hydrothermal systems.

  10. Active hydrothermal metamorphism in the Cerro Prieto geothermal system, Baja California, Mexico: a telescoped low P/T facies series. [Abstract only

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, P. (Univ. of California, Riverside); Elders, W.A.; Williams, A.E.; McDowell, S.D.; Bird, D.K.

    1983-03-01

    In the Cerro Prieto geothermal system, carbonate-cemented, quartzo-feldspathic sediments of the Colorado River delta are being actively recrystallized into calc-silicate metamorphic rocks through intense fluid/rock interaction with alkali chloride brine (1.5 x 10/sup 4/ ppM TDS) at temperatures between 200/sup 0/ and 370/sup 0/C, fluid pressures <0.25 Kb, lithostatic pressures <1.0 Kb, and oxygen fugacities close to the QFM buffer. Petrologic investigations of cuttings and core from more than 50 wells in this field reveal a prograde series of calc-silicate mineral zones with index metamorphic minerals: wairakite (wr), epidote (ep), prehnite (pr), and calcic clinopyrosene (cpx). The compositions of these and other key phases: wr (Ca/Ca + Na + K + 0.97), ep (Fe/Fe + Al/sup vi/ = 0.11 to 0.31), pr (Fe/Fe + Al/sup vi/ = 0.01 to 0.28), cps (close to Wo/sub 50/ and Mg/Mg + Fe + Mn = 0.23 to 0.90), actinolite (0.20 Al/sup iv//15 cations and Mg/Mg + Fe + Mn = 0.67 to 0.82), biotite (Mg/Mg + Fe + Mn = 0.58 to 0.87) and microcline (Or/sub 96 to 100/) reflect recrystallization under low fluid pressures, relatively low f/sub O/sub 2//, and varying brine compositions. Divariant mineral assemblages in this system comprise a very low P/T facies series encompassing the clay-carbonate, zeolite, greenschist, and amphibolite facies and reflect equilibrium occurring in response to both increasing temperature and decreasing CO/sub 2/ pressure. Similar facies series, characterized by telescoped devolatization mineral reactions, are becoming increasingly recognized in other active geothermal systems above 300/sup 0/C. However, close analogues in the fossil geologic record are as yet unidentified.

  11. Relationship between self-reported fish and shellfish consumption, carbon and nitrogen stable isotope values and total mercury concentrations in pregnant women (II from Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Rebecca Bentzen

    2014-01-01

    Full Text Available Seafood is a valuable source of nutrients important for fetal development. However, seafood consumption is the main route of exposure to monomethyl mercury (MeHg+ for humans. MeHg+ is highly bioavailable and potentially adversely affects fetal neurodevelopment. MeHg+ exposure from fish consumption varies significantly by age and trophic level of fish consumed as well as the frequency and amount of fish consumed. This study investigates total Hg concentrations ([THg] in hair segments of pregnant Mexican women in relation to (1 self-reported frequency of fish and shellfish consumption, (2 maternal trophic level and marine diet contributions, determined using hair carbon (C and nitrogen (N stable isotopes, and (3 relates [THg] to various hair advisory thresholds. We also examined whether variation in C and N isotope values is explained by self-reported frequency of fish and shellfish consumption. A significant proportion of hair samples had [THg] higher than suggested agency thresholds and, for women within the range of the various advisory thresholds (1–20 μg g−1, the specific statistic used and threshold applied are important considerations for assessing and communicating risk. Individuals enriched in 15N (δ15N values had higher [THg] as did individuals that reported consuming fish and shellfish more frequently, suggesting that variation in [THg] can be explained by both consumer reported diet and diet as determined by C and N stable isotope assessment. However, at higher reported fish consumption levels the trophic level is maintained while [THg] is paradoxically lower. This suggests that THg exposure and assimilation are more complicated in higher fish frequency consumption categories. [THg] is more variable at the higher concentrations, possibly indicating some exposure to non-dietary Hg, heritable variations affecting Hg toxicodynamics, and BMI and tobacco exposure factors as outlined in our companion paper.

  12. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    Energy Technology Data Exchange (ETDEWEB)

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S

    2011-03-03

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  13. Mercury Concentrations in Pacific Angel Sharks (Squatina californica) and Prey Fishes from Southern Gulf of California, Mexico.

    Science.gov (United States)

    Escobar-Sánchez, O; Ruelas-Inzunza, J; Moreno-Sánchez, X G; Romo-Piñera, A K; Frías-Espericueta, M G

    2016-01-01

    Concentrations of mercury (Hg) were quantified in muscle tissues of the Pacific angel shark, Squatina californica sampled from Southern Gulf of California, Mexico, considering total length, sex, diet and the dietary risk assessment. High Hg levels are typically associated with carnivorous fishes, however S. californica showed low Hg concentrations (shark (p > 0.05). Hg concentrations were highest in the darkedge mishipman: Porichthys analis (0.14 ± 0.08 µg g(-1)) and red-eye round herring Etrumeus teres (0.13 ± 0.05 µg g(-1)) relative to other prey species, which could suggest that Hg concentrations in S. californica were influenced by these species. Given the relatively low concentration of Hg across age-classes and sex, consumption of S. californica's muscle tissue poses limited risk to humans.

  14. Earthquake Cycle Deformation at the Ballenas Transform, Gulf of California, Mexico, from InSAR and GPS Measurements

    Science.gov (United States)

    Plattner, Christina; Fattahi, Heresh; Malservisi, Rocco; Amelung, Falk; Verdecchia, Alessandro; Dixon, Timothy H.

    2015-05-01

    We study crustal deformation across the Ballenas marine channel, Gulf of California, Mexico using InSAR and campaign GPS data. Interseismic velocities are calculated by time-series analysis spanning five years of data. Displacements from the August 3rd 2009 Mw 6.9 earthquake are calculated by differencing the most recent observations before and after the event. To estimate the offset across the marine channel we calibrate the InSAR velocity and displacement fields using the corresponding GPS data. Unfortunately, the InSAR interseismic velocity field is affected by residual tropospheric delay. We interpret the GPS interseismic and the GPS and InSAR coseismic deformation data using dislocation modeling and compare the fault kinematics during these periods of the earthquake cycle.

  15. Non-selective in situ grazing of diatoms by juvenile Green Abalone (Haliotis fulgens Philippi, 1945 in the Baja California Peninsula Consumo in situ no selectivo de diatomeas por juveniles de abulón azul (Haliotis fulgens Philippi, 1945 en la Península de Baja California

    Directory of Open Access Journals (Sweden)

    Uri Argumedo Hernández

    2010-04-01

    determinaron sus abundancias relativas; 42% fueron epifitas. Catorce taxa representaron el 80% de la abundancia total; de estos 12 han sido propuestos como los más importantes en la dieta de juveniles de abulón en la costa W de BCS. Los valores de diversidad (H' variaron entre 1.05 y 4.47 y dependieron más de la dominancia que de la riqueza de especies, reflejando la diversidad de diatomeas en el hábitat. Estas observaciones y la baja similitud medida entre contenidos intestinales, muestran que la riqueza y diversidad de especies de diatomeas ingeridas por juveniles de abulón serán similares aun cuando la composición de especies de diatomeas sea distinta entre especímenes. Esto nos permite concluir que la ingestión de diatomeas por juveniles de abulón es no selectiva y que la estructura de las asociaciones de diatomeas es más importante que los taxa específicos en su dieta.

  16. Humanitarismo, redención y ciencia médica en Nueva España: El expediente de salud pública para frenar la extinción de indios en la Baja California (1797-1805 Humanitarianism, Redemption and Medical Science in New Spain: The Public Health Plan to Halt the Extinction of Indians in Baja California (1797-1805

    Directory of Open Access Journals (Sweden)

    Francisco Altable

    2011-08-01

    Full Text Available A partir de la descripción de los diversos momentos de la puesta en marcha de un programa médico diseñado para revertir el largo proceso de decadencia poblacional de los indios de la península de California, se pone a la vista lo que podría denominarse el humanitarismo político de la corona española, proyectado en el debate habido entre las perspectivas religiosa y científica en torno a la extinción de los indios. El artículo explica las causas de lo que se denomina aquí la utopía de la sanación de los californios y ofrece una interpretación que varía de las concepciones relativas a la consabida incapacidad génica de los indios para sobrevivir a los contagios, a los errores e imposiciones del proceso de aculturación y a otros factores adversos a la existencia indígena. Se concluye que el fracaso del programa médico en cuestión contribuyó a la frustración de las expectativas colonizadoras, humanitarias, religiosas y modernizadoras del régimen borbónico.On the basis of a description of various moments in the implementation of a medical program to reverse the long population decline of Indians in the California península, what could be called the political humanitarianism of the Spanish Crown emerged, projected onto the debate between the religious and scientific perspectives regarding the extinction of the Indians. The árdele explains the causes of what is called the Utopia of the Californians' healing, offering an interpretation that ranges from relative conceptions to the Indians' well-known genetic capacity to survive the infections, errors and impositions of the acculturation process and other factors that adversely affect indigenous existence. It concludes that the failure of the medical program in question contributed to the frustration of the colonizing, humanitarian, religious and modernizing expectations of the Bourbon regime.

  17. Avifauna de la selva baja caducifolia en la cañada del río Sabino, Oaxaca, México Avifauna of the tropical dry forest in the Sabino Canyon, Oaxaca, Mexico

    OpenAIRE

    2009-01-01

    Se describe la avifauna de la selva baja caducifolia del cañón del río Sabino, Oaxaca, al sureste de la Reserva de la Biosfera Tehuacán-Cuicatlán y compara la similitud de la avifauna de la Reserva con la de otras regiones con selvas bajas en México. El trabajo se realizó entre junio de 2005 y octubre de 2006, registrando 113 especies pertenecientes a 13 órdenes y 34 familias; 6 especies son muy abundantes, 10 abundantes, 20 comunes, 32 poco comunes y 37 raras; 79 de las especies registradas ...

  18. Mercury poisoning associated with beauty cream--Texas, New Mexico, and California, 1995-1996.

    Science.gov (United States)

    1996-05-17

    The Texas Department of Health (TDH), New Mexico Department of Health (NMDH), and San Diego County Health Department (SDCHD) recently investigated three cases of mercury poisoning among persons who had used a beauty cream produced in Mexico. The investigations implicated the beauty cream as the source of the mercury. The cream, marketed as "Crema de Belleza--Manning," lists "calomel" (mercurous chloride) as an ingredient and was found to contain 6%-8% mercury by weight. This report summarizes the ongoing investigation of these and other possible cases.

  19. Trace metal concentrations and lead isotopic composition in surface waters of the Northeast Pacific along the United States - Mexico boundary

    Energy Technology Data Exchange (ETDEWEB)

    Sanudo-Wilhelmy, S. (Inst. of Marine Science, Santa Cruz, CA (United States))

    1990-01-09

    To evaluate the magnitude of heavy metal contamination along the United States - Mexico boundary, trace metal concentrations (Pb, Cd, Mn, Fe, and Zn) and lead isotopic composition ([sup 204]Pb, [sup 206]Pb, [sup 207]Pb, and [sup 208]Pb) were measured along four surface water transects across the continental shelf off the Baja California Coast. The stations were located between 2 to 45 km offshore, including both coastal and open ocean locations. All the metal distributions along the transects were characterized by offshore concentration gradients. The highest trace metal concentrations occurred in coastal waters in association with high salinities and nutrient concentrations. There was also a longshore gradient in trace metal concentrations. Trace element concentrations were lower in the southern locations than along the United States - Mexico boundary, and were comparable to typical open ocean values. The relative enrichment of metals in surface waters off the northern part of Baja California was primarily associated with advection/upwelling processes, not with anthropogenic inputs. Mass balance calculations indicated that about 1% of Cd and 13% of Zn were from urban discharges. The low metal levels measured in coastal waters off the central part of Baja California were attributed to the intrusion of open ocean waters, based on hydrographic data, satellite images and lead isotopic compositions.

  20. Summary of the 2010 assessment on medium- to low-temperature geothermal resources in Mexico; Resumen de la evaluacion 2010 de los recursos geotermicos mexicanos de temperatura intermedia a baja

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, Eduardo R.; Torres, Rodolfo J.; Martinez Estrella, J. Ignacio; Reyes Picasso, Neftali [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: iglesias@iie.org.mx

    2011-07-15

    geothermal systems lies between 1,168 EJ and 1,274 EJ, with 90% confidence. The statistical distribution of the (conservatively) inferred reservoir temperatures indicates that 5% of these systems have temperatures between 151 and 208 degrees Celsius, 40% of these systems have temperatures between 102 and 151 degrees Celsius, 50% of these systems have temperatures between 60 and 102 degrees Celsius, and 5% of these systems have temperatures between 36 and 60 degrees Celsius. These resources contain massive amounts of thermal energy that could be used in a wide variety of direct applications and power generation projects. Potentially they are important for the economy of 26 of the 32 Mexican States. This work does not include any attempt to estimate the recuperation factor of the estimated resources. [Spanish] En 2003 publicamos nuestra primera estimacion de los recursos geotermicos mexicanos de temperatura intermedia a baja (T {<=} 200 grados centigrados) con base en datos de 1358 manifestaciones superficiales identificadas en ese momento. Debido a falta de informacion en uno o mas parametros relevantes, como coordenadas geograficas, temperatura de muestra o del yacimiento, etc., dicha evaluacion incluyo aproximadamente 30% de las manifestaciones identificadas. Desde entonces nuestro grupo incremento significativamente la cantidad de la informacion en la base de datos, mediante compilacion de datos de diferentes fuentes y trabajo de campo. Posteriormente desarrollamos una base de datos relacional y la implementamos en un Sistema de Informacion Geografica (SIG). En este trabajo presentamos un resumen de nuestra evaluacion 2010 de los recursos geotermicos mexicanos de temperatura intermedia a baja resultante de nuestra base de datos actualizada, que incluye 2361 manifestaciones geotermicas. Como en la version precedente, utilizamos el metodo volumetrico y simulaciones Montecarlo para estimar los recursos geotermicos y sus correspondientes incertidumbres para cada sistema

  1. Organchlorine content and shell thickness in brown booby (Sula leucogaster) eggs in the Gulf of California and the southern Pacific coast of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mellink, Eric, E-mail: emellink@cicese.m [Departamento de Biologia de la Conservacion, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C. Carretera Tijuana-Ensenada Km. 107, 22860 Ensenada, B.C. (Mexico); Riojas-Lopez, Monica E., E-mail: meriojas@cucba.udg.m [Departamento de Ecologia, Centro Universitario de Ciencias Biologicas y Agropecuarias, Universidad de Guadalajara, Km. 15.5 Carretera a Nogales, 45100 Zapopan, Jalisco (Mexico); Luevano-Esparza, Jaime, E-mail: jluevano@cicese.m [Departamento de Biologia de la Conservacion, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C. Carretera Tijuana-Ensenada Km. 107, 22860 Ensenada, B.C. (Mexico)

    2009-07-15

    We determined egg concentrations of organochlorines and thickness of eggshells from brown boobies at eight colonies ranging from the northern Gulf of California to southern Mexico. The only common residue was that of DDE, which was found in almost all eggs. DDE content apparently reflected pre-1990 DDT use in nearby agricultural areas and, at one site, intensive mosquito control for high-end tourism development. There were no inter-colony differences in eggshell thickness, and variation in this variable likely reflected individual bird characteristics and/or individual feeding source. This variable was not a good proxy to DDE exposure of brown boobies, under current DDE levels in the brown booby trophic chain. In the northern Gulf of California, eggshell thickness has recovered to pre-DDT conditions. Our data indicate that the Gulf of California and southwestern coast of Mexico have a healthy near-shore marine environment, as far as organochlorines are concerned. - Wide-range, current picture of organochlorine presence in the environment along the western coast of Mexico.

  2. Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico.

    Science.gov (United States)

    Pettit, L R; Hart, M B; Medina-Sánchez, A N; Smart, C W; Rodolfo-Metalpa, R; Hall-Spencer, J M; Prol-Ledesma, R M

    2013-08-30

    Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution.

  3. Efecto del blanqueamiento del coral por baja temperatura en los crustáceos decápodos asociados a arrecifes del suroeste del golfo de California Effect of coral bleaching induced by low temperature on reef-associated decapod crustaceans of the southwestern Gulf of California

    Directory of Open Access Journals (Sweden)

    Luis Hernández

    2010-10-01

    Full Text Available El blanqueamiento del coral es consecuencia de un estrés natural o antropogénico sobre los arrecifes. En la región del Pacífico tropical este, el blanqueamiento del coral se asocia comúnmente con el incremento de la temperatura superficial del mar, pero también se puede presentar por temperaturas bajas. A principio de 2008 se registró una anomalía de temperatura extraordinariamente baja, de hasta 1.8 °C menor al promedio registrado en los últimos 25 años, que se manifestó con un severo blanqueamiento de corales en varias localidades al sur del golfo de California, alcanzando cifras de hasta el 90% del coral blanqueado. El objetivo del presente trabajo fue describir los cambios en el ensamblaje de decápodos asociados a los arrecifes en la región afectada. Las bahías de La Paz (24° N y Loreto (26° N fueron visitadas antes, durante y después del evento, realizándose censos visuales en 6 sitios de cada bahía. Los resultados muestran que la riqueza y dominancia de decápodos cambió por efecto del blanqueamiento. La afectación fue diferencial entre ambas localidades: la fauna coralina de la región de Loreto fue más afectada que la de bahía de La Paz y los cambios en los ensamblajes de decápodos fueron diferentes.Coral reef bleaching is a common stress response to natural or anthropogenic events. In the Tropical East Pacific, coral reef bleaching has been commonly associated to temperature increase of the sea surface, but it can also occur with low temperatures. In early 2008, an abnormality of very low temperature was recorded, up to 1.8 °C lower than the average temperature in the last 25 years, and a severe coral bleaching was observed in numerous localities in the southern part of the Gulf of California, which rose up to 90% of coral bleaching in some places. The aim of this work was to describe changes in decapod assemblages associated to coral reefs in the affected region. La Paz (24°N and Loreto (26°N bays were

  4. Influenza-like Illness Surveillance on the California-Mexico Border, 2004-2009

    Science.gov (United States)

    2011-01-01

    assay with type- specific monoclonal antibodies for viral identification. Hemagglutination inhibition was used to serotype influenza isolates using...estimated in 2001, the US-Mexico bor- der is one of the busiest in the world. Incidence rates for infectious diseases, such as diphtheria , hepatitis...modification of a final concentration of probe to 0Æ3 lm per 25 ll reaction. pH1N1 testing Samples were assayed for pH1N1 by using the Emergency Use

  5. Multiproxy Study of a Holocene Record From Western Pescadero Basin, Gulf of California, Mexico: Paleoclimatic inferences

    Science.gov (United States)

    Perez-Cruz, L. L.; Valdez, M.; Roy, P. D.

    2013-12-01

    A sedimentary sequence (gravity core T-56, 256 cm length) from Pescadero Basin on the western side of the Gulf of California is analyzed as part of a multiproxy study. The core was collected within the Oxygen Minimum Zone (OMZ) at 597 m depth, aboard of the R/V "El Puma". Pescadero basin is located at mouth of the gulf; in a location sensitive to record the changes in the gulf and the Eastern Pacific Ocean. The sedimentary sequence is analyzed to contribute to understanding the climatic variability in the southern part of the gulf of California during the Holocene using geochemistry (major and trace elements and Corg), magnetic properties and benthic foraminifera assemblages as proxy of changes in paleoproductivity, paleoprecipitation and bottom water oxygenation. The core is characterized by silty-clay sediments, and exhibits a turbidite between 130 and 235 cm, distinguished by sandy sediments and reworking material. From 130 cm to the top it shows a visible laminated structure. Chronology is based on six AMS radiocarbon dates, and estimated sedimentation rates are 0.22, 0.18, 0.17 and 0.05 mm/yr. The core covers c. last 10,500 years. Variations in major and trace elements (Ti, K, Al, K, Zr) and magnetic susceptibility indicate fluctuations in terrigenous input related to changes in hydrological conditions, Benthic foraminifera assemblages and Corg along the sequence indicate that Pescadero basin is sensitive to paleoceanographic changes. Corg and benthic foraminiferal assemblages show downcore variations related to paleoproductivity changes. For the Early Holocene, low values of Corg and epifaunal benthic foraminifera suggest oxic conditions in bottom waters and strong stratification with low productivity. Organic carbon shows higher values towards the bottom of the core, for the last 1300 years.

  6. Benthic foraminifera records in marine sediments during the Holocene from Pescadero basin, Gulf of California, Mexico

    Science.gov (United States)

    Valdez, M.; Perez-Cruz, L. L.; Roy, P.; Monreal, M.; Fenero, R.

    2013-05-01

    Gravity core T-56 (256 cm length) was collected in Pescadero Basin located on the western side of the Gulf of California within the oxygen minim zone (OMZ) at 597 cm depth, aboard of the R/V "El Puma". Pescadero basin is located at mouth of the gulf; because of its location is sensitive to record the changes in the gulf and in the Eastern Pacific Ocean. The sedimentary sequence is analyzed to contribute to the understanding the oceanographic variability in the southern part of the gulf of California during the Holocene using benthic foraminifera assemblages and organic carbon as proxies of organic matter flux and bottom water oxygenation. In general, the core is characterized by silty-clay sediments, and it exhibits a turbidite between 198 and 134 cm, distinguished by sandy sediments and reworking material. From 134 cm to the top shows a visible laminated structure. The initial chronology is based on three AMS radiocarbon dates, and estimated sedimentation rates are 0.22 and 0.19 mm/yr for the first 32 cm of the core. Six radiocarbon dates are in progress. Preliminary results of benthic foraminiferal assemblages showed that species of Bolivina are dominated, mainly megalospheric forms, from 134 cm to top of the core. They are small and thin-shelled forms (e.g., Bolivina subadvena, Bolivina minuta, Bolivina seminuda, Bolivina plicata), and also Buliminella, Cassidulina and Epistominella are abundant. In particular, species of Bolivina are environmental indicators and exhibit a typical reproductive dimorphism. The predominance of the genus Bolivina suggest organic flux variations, because of the productivity changes that might be related to changes in ocean circulation and in the environmental variability in the region.

  7. The BOOTES-5 telescope at San Pedro Martir National Astronomical Observatory, Mexico

    Science.gov (United States)

    Hiriart, D.; Valdez, J.; Martínez, B.; García, B.; Cordova, A.; Colorado, E.; Guisa, G.; Ochoa, J. L.; Nuñez, J. M.; Ceseña, U.; Cunniffe, R.; Murphy, D.; Lee, W.; Park, Il H.; Castro-Tirado, A. J.

    2016-12-01

    BOOTES-5 is the fifth robotic observatory of the international network of robotic telescopes BOOTES (Burst Observer and Optical Transient Exploring Optical System). It is located at the National Astronomical Observatory at Sierra San Pedro Martir, Baja California, Mexico. It was dedicated on November 26, 2015 and it is in the process of testing. Its main scientific objective is the observation and monitoring of the optic counterparts of gamma-ray bursts as quickly as possible once they have been detected from space or other ground-based observatories. BOOTES-5 fue nombrado Telescopio Javier Gorosabel en memoria del astrónomo español Javier Gorosabel Urkia.

  8. Biomagnification of mercury and selenium in Blue Shark Prionace glauca from the Pacific Ocean off Mexico

    OpenAIRE

    Escobar-Sánchez, Ofelia; Galván Magaña, Felipe; Rosíles-Martínez, René

    2011-01-01

    The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks. High levels of mercury were found in shark muscle tissues (1.39±1.58 μg/g wet weight); these values are above the allowed 1.0 μg/g for human consumption. The Mercury to selenium molar ratio was 1:0.2. We found a low correlation between ...

  9. Very early supratidal diagenesis in washover sediments, Puerto Penasco, Gulf of California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lock, B.E.; Broussard, D.L.

    1988-02-01

    Puerto Penasco, Sonora, Mexico is built on a macrotidal (tidal range up to 7 m) barrier complex. East of the town, a filled washover channel has been cut off from the sea by dune migration, but has experienced periodic inundation by marine waters - most recently as part of an aquaculture program. The climate is hot (mean August air temperature 30/degrees/C (86/degrees/F), mean annual rainfall 7.4 cm (2.9 in.)). Unconsolidated sand samples from core material were dehydrated with alcohol and impregnated with L. R. White resin, an extremely low viscosity agent used primarily by biologists. This resin is cured at 65/degrees/C (149/degrees/F), a temperature unlikely to significantly modify sensitive mineralogies over the short times involved. The method was extremely successful in preserving highly delicate microstructures such as micrite-filled endolithic algal borings within hollow micrite envelopes. Study of cored material from this sand body reveals a surprisingly complex diagenetic history, probably representing at most a few hundred years. Marine flooding episodes have introduced sulfates and chlorides; freshwater influx, perhaps following infrequent heavy rains, has led to partial dissolution of evaporites and redistributions of carbonate. Long time periods clearly are not a prerequisite for complex diagenetic changes in clastic sediments.

  10. Fish Larvae Response to Biophysical Changes in the Gulf of California, Mexico (Winter-Summer

    Directory of Open Access Journals (Sweden)

    Raymundo Avendaño-Ibarra

    2013-01-01

    Full Text Available We analyzed the response of fish larvae assemblages to environmental variables and to physical macro- and mesoscale processes in the Gulf of California, during four oceanographic cruises (winter and summer 2005 and 2007. Physical data of the water column obtained through CTD casts, sea surface temperature, and chlorophyll a satellite imagery were used to detect mesoscale structures. Zooplankton samples were collected with standard Bongo net tows. Fish larvae assemblages responded to latitudinal and coastal-ocean gradients, related to inflow of water to the gulf, and to biological production. The 19°C and 21°C isotherms during winter, and 29°C and 31°C during summer, limited the distribution of fish larvae at the macroscale. Between types of eddy, the cyclonic (January registered high abundance, species richness, and zooplankton volume compared to the other anticyclonic (March and cyclonic (September. Thermal fronts (Big Islands of January and July affected the species distribution establishing strong differences between sides. At the mesoscale, eddy and fronts coincided with the isotherms mentioned previously, playing an important role in emphasizing the differences among species assemblages. The multivariate analysis indicated that larvae abundance was highly correlated with temperature and salinity and with chlorophyll a and zooplankton volume during winter and summer, respectively.

  11. The California Border Health Collaborative: A Strategy for Leading the Border to Better Health

    Directory of Open Access Journals (Sweden)

    Charles Edwards Matthews III

    2015-05-01

    Full Text Available There are hundreds of departments and organizations working on border health issues in the California/Baja California border region trying to protect and improve health without a collaborative structure that integrates jurisdictions and organizations. As a result, there is a need to effectively improve the health in the border region by coordinating these organizations to work together and benefit from each other’s best practices. The newly developed California Border Health Collaborative (CBHC can provide the leadership and collaborative culture to positively improve the health of the border region. This article aims to describe the development process of this collaborative to include key ingredients to success, the roles of mulit-level jurisdictions, and policy implications.This article describes the methods used to develop key aspects of collaborative leadership, strategic alignment and a common vision toward the building of this collective impact approach to border health. In addition, we describe the role of key local County (County of San Diego Live Well San Diego initiative, State, (California Department of Public Health- Office of Binational Border Health, Federal (US-Mexico Border Health Commission’s Leaders across Borders, Academia (e.g., University of California San Diego and San Diego State University and non-profit entities (e.g., Project Concern International, San Ysidro Health Center in forming the BHCC. Evaluating the consortium development process included a literature review of similar processes, a review of internal documents and an analysis of developmental events. To this point the CBHC has built a strong, cohesive collaborative on the U.S. side of the border. It is sharing and leveraging local expertise to address many border health issues. Even more importantly, the BHCC has reached a key stage in which it can effectively engage its Baja California, Mexico counterparts in a manner that will prove extremely powerful

  12. Larval fish assemblages, environment and circulation in a semienclosed sea (Gulf of California, Mexico)

    Science.gov (United States)

    Peguero-Icaza, M.; Sánchez-Velasco, L.; Lavín, M. F.; Marinone, S. G.

    2008-08-01

    Fish larvae and hydrographic data collected in the Gulf of California (GC) in December 2002 are used to describe larval fish assemblages (LFAs) and to explore their relationships with environmental variables (temperature, salinity, dissolved oxygen, fluorescence maximum, ϕ and superficial chlorophyll a). The Bray-Curtis dissimilarity index defined three LFAs, distributed in areas with distinctly different environmental conditions. The affinity of most of the species with the environmental characteristics of their areas of distribution could be interpreted as an indication that spawning occurred inside those areas. Particle tracking in current fields from a 3D numerical model and connectivity matrices are used to assess larval retention in the LFA areas. The technique is well suited for seas like the GC that have well-defined circulation patterns. On time scales around 30 days, retention (from 56% to 73% of the particles) occurred (1) for the North LFA in the Upper GC, (2) for the Channel-Center LFA in the anticyclone over the Northern GC and in Ballenas Channel, and (3) for the South LFA in the eddy over San Pedro Mártir basin and in the shallow zone off the peninsula. Therefore, the Lagrangian analysis revealed that the observed LFAs have a permanency long enough to allow fish larvae to remain in a favorable environment until they develop motility. The main particle export path (less than 26% of the particles) was from the North to the South LFA, following the anticyclonic main flow and coinciding with the gradient in species number and larval abundance.

  13. Prevalence of risk factors for HIV infection among Mexican migrants and immigrants: probability survey in the north border of Mexico

    Directory of Open Access Journals (Sweden)

    Gudelia Rangel M.

    2006-01-01

    Full Text Available OBJECTIVE: To estimate the prevalence of risk factors for HIV infection among Mexican migrants and immigrants (MMIs in different geographic contexts, including the sending communities in Mexico, the receiving communities in the United States (US, and the Mexican North border region. MATERIAL AND METHODS: We conducted a probability survey among MMIs traveling through key border crossing sites in the Tijuana (Baja California, Mexico-San Diego (California, US border region (N=1 429. RESULTS: The survey revealed substantial rates of reported sexually transmitted infections, needle-sharing and sexual risk practices in all migration contexts. CONCLUSIONS: The estimated levels of HIV risk call for further binational research and preventive interventions in all key geographic contexts of the migration experience to identify and tackle the different personal, environmental, and structural determinants of HIV risk in each of these contexts.

  14. Pandemic (H1N1) 2009 Surveillance in Marginalized Populations, Tijuana, Mexico, and West Nile Virus Knowledge among Hispanics, San Diego, California, 2006

    Centers for Disease Control (CDC) Podcasts

    2010-08-10

    This podcast describes public health surveillance and communication in hard to reach populations in Tijuana, Mexico, and San Diego County, California. Dr. Marian McDonald, Associate Director of CDC's Health Disparities in the National Center for Emerging and Zoonotic Infectious Diseases, discusses the importance of being flexible in determining the most effective media for health communications.  Created: 8/10/2010 by National Center for Emerging and Zoonotic Infectious Diseases, National Center for Immunization and Respiratory Diseases.   Date Released: 8/10/2010.

  15. [Asthma mortality trends in Mexico].

    Science.gov (United States)

    Salas Ramírez, M; Segura Méndez, N H; Martínez-Cairo Cueto, S

    1994-04-01

    The objective of this cross-sectional study was to estimate mortality and morbidity from asthma in Mexico by federative entity (state) of residence, age, and sex during the period between 1960 and 1988. Statistics published by the National Institute of Statistics, Geography, and Information Science were reviewed, as were vital statistics and information from other sources. Data were selected on mortality, hospital admissions, and outpatient visits, as well as population by federative entity, age, and sex. Mortality and morbidity rates were adjusted for age using the direct method. From 1960 to 1987, mortality decreased for both sexes. The groups with the highest asthma mortality were those under 4 years of age and those over 50. From 1960 to the present, the state with the highest mortality was Tlaxcala. Hospitalizations increased from 10 to 140 per 100,000 population for the country as a whole. When both outpatient visits and hospitalizations were considered, the morbidity rates rose from 180 to 203.4 per 100,000 between 1960 and 1970. In 1970, hospital morbidity was higher among males than females. From 1960 up to the 1990s, the highest rates of hospitalization and outpatient visits were registered among those under 4 and those over 60. The states with the highest asthma hospitalization rates were Morelos, Baja California Sur, Nuevo León, Durango, and Tamaulipas. It is concluded that asthma mortality in Mexico is showing a downward trend, while morbidity is increasing considerably, especially among adolescents.

  16. Anticoagulant screening of marine algae from Mexico, and partial characterization of the active sulfated polysaccharide from Eisenia arborea

    OpenAIRE

    Muñoz Ochoa, Mauricio; Murillo-Álvarez, Jesús Iván; Rodríguez Montesinos, Yoloxochilt Elizabeth; Hernández Carmona, Gustavo; Arvizu Higuera, Dora Luz; Peralta Cruz, Javier;; Lizardi Mendoza, Jaime

    2009-01-01

    The in vitro anticoagulant activity of 41 water extracts of various seaweeds from Baja California Sur, Mexico was evaluated. In this study, nine extracts exhibited anticoagulant activity in the prothrombin time assay, and 29 extracts were active in the activated partial thromboplastin time assay. The water extract obtained at 25°C from the brown seaweed Eisenia arborea was the most active in both assays, increasing the normal blood clotting-time over 300 s at 100 mg mL-1. The fractionation of...

  17. Correction of locality records for the endangered arroyo toad (Anaxyrus californicus) from the desert region of southern California

    Science.gov (United States)

    Ervin, Edward L.; Beaman, Kent R.; Fisher, Robert N.

    2013-01-01

    The recovery strategy for an endangered species requires accurate knowledge of its distribution and geographic range. Although the best available information is used when developing a recovery plan, uncertainty often remains in regard to a species actual geographic extent. The arroyo toad (Anaxyrus californicus) occurs almost exclusively in coastal drainages, from Monterey County, California, south into northwestern Baja California, Mexico. Through field reconnaissance and the study of preserved museum specimens we determined that the four reported populations of the arroyo toad from the Sonoran Desert region of Riverside, San Diego, and Imperial counties, California are in error. Two additional sites in the Sonoran Desert are discussed regarding the possibility that the arroyo toad occurs there. We recommend the continued scrutiny of arroyo toad records to maintain a high level of accuracy of its distribution and geographic extent.

  18. Modern non-tropical mixed carbonate-siliciclastic sediments and environments of the southwestern Gulf of California, Mexico

    Science.gov (United States)

    Halfar, Jochen; Ingle, James C.; Godinez-Orta, Lucio

    2004-03-01

    Modern mixed carbonate-siliciclastic warm-temperate environments were studied in the southern Gulf of California (GOC), Mexico. The combined heterozoan and photozoan character is defined by the absence of true coral reef structures, calcareous green algae and non-skeletal grains, and the dominance of rhodoliths (unattached coralline red algae), mollusks and small coral patch reefs. The major carbonate producing environments are pocket bays, a shallow carbonate bioherm, high-energy rocky and sandy shorelines and mid-shelf settings. Sediments characterizing the pocket bays display heavily bioturbated bioclastic wackestone and grainstone textures. The rhodolith dominated bioherm is composed of coarse sediments exhibiting grainstone and rudstone textures with fine material being winnowed away by tidal currents. Rocky and sandy shorelines are characterized by erosion and mixing of up to boulder size granitic and volcaniclastic material with coralline red algal and molluskan carbonates. The mid-shelf settings are defined by a silt and fine sand sized non-carbonate matrix mixed with abundant molluskan fragments and foraminifera. Peak carbonate production takes place between 10 and 15 m water depth; below 40 m production significantly decreases, combined with a steep increase in the amount of siliciclastics. This is in contrast to many temperate and cool-water mixed-carbonate siliciclastic systems, where most carbonate production occurs in mid- to outer shelf settings. A full spectrum of sediments from pure carbonates (90-100% carbonate), allochem carbonates (50-90% carbonate) and allochemic mud or sand (<50% carbonate) was encountered in the study area. The absence of early diagenetic binding and cementation of the non-tropical carbonates facilitates mixing of carbonates and siliciclastics. The latter are mainly derived from adjacent Tertiary volcaniclastics and Mesozoic granites. Mixing takes place (1) as punctuated mixing during periodic short-term storm or hurricane

  19. The involvement of citizens evaluating public security policies: Baja California’s case

    Directory of Open Access Journals (Sweden)

    Pablo Jesús González Reyes

    2003-07-01

    Full Text Available This paper emphasizes the importance of citizen involvement in the evaluation processes of public security policy in Baja California, as a revealing need of establishing new options for public management, through which relationships of mutual responsibility between society and government are enacted.

  20. Structural inheritance versus magmatic weakening: What controls the style of deformation at rift segment boundaries in the Gulf of California, Mexico?

    Science.gov (United States)

    Seiler, Christian; Gleadow, Andrew; Kohn, Barry

    2013-04-01

    Rifts are commonly segmented into several hundred kilometre long zones of opposing upper-plate transport direction with boundaries defined by accommodation and transfer zones. A number of such rift segments have been recognized in the Gulf of California, a youthful oceanic basin that is currently undergoing the rift-drift transition. However, detailed field studies have so far failed to identify suitable structures that could accommodate the obvious deformation gradients between different rift segments, and the nature of strain transfer at segment boundaries remains enigmatic. The Bocana transfer zone (BTZ) in central Baja California is a linear, WNW striking structural discontinuity separating two rift segments with different magnitudes and styles of extensional deformation. North of the BTZ, the Libertad fault is part of the Main Gulf Escarpment, which represents the breakaway fault that separates the Gulf of California rift to the east from the relatively stable western portion of the Baja peninsula. The N-striking Libertad escarpment developed during the Late Miocene (~10-8Ma) and exhibits a topographic relief of ca. 1,000m along a strike-length of ca. 50km. Finite displacement decreases from ~1000m in the central fault segment to ~500m further south, where the fault bends SE and merges with the BTZ. In the hanging wall of the Libertad fault, a series of W-tilted horsts are bound along their eastern margins by two moderate-displacement E-dipping normal faults. South of the BTZ, extension was much less than further north, which explains the comparatively subdued relief and generally shallower tilt of pre-rift strata in this area. The BTZ itself is characterized by two en echelon WNW-ESE striking dextral-oblique transfer faults with a significant down-to-the-NNE extensional component. Strain is transferred from the Libertad breakaway fault onto the transfer faults over a distance of >20km through a network of interacting normal, oblique and strike-slip faults