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Sample records for zapotitlan valley mexico

  1. A new Proposal to Mexico Valley Zonification

    Science.gov (United States)

    Flores-Estrella, H. C.; Yussim, S.; Lomnitz, C.

    2004-12-01

    The effects of the Michoacan earthquake (19th September, 1985, Mw 8.1) in Mexico City caused a significant change in the political, social and scientific history, as it was considered the worst seismic disaster ever lived in Mexico. Since then, numerous efforts have been made to understand and determine the parameters that caused the special features registered. One of these efforts had began on 1960 with the work by Marsal and Masari, who published the Mexico Valley seismological and geotechnical zonification (1969), based on gravimetric and shallow borehole data. In this work, we present a revision of the studies that proposed the zonification, a description of the valley geology, and basing on it we propose a new zonification for Mexico Valley.

  2. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2015-04-01

    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  3. Ventilation potential during the emissions survey in Toluca Valley, Mexico

    Science.gov (United States)

    Ruiz Angulo, A.; Peralta, O.; Jurado, O. E.; Ortinez, A.; Grutter de la Mora, M.; Rivera, C.; Gutierrez, W.; Gonzalez, E.

    2017-12-01

    During the late-spring early-summer measurements of emissions and pollutants were carried out during a survey campaign at four different locations within the Toluca Valley. The current emissions inventory typically estimates the generation of pollutants based on pre-estimated values representing an entire sector function of their activities. However, those factors are not always based direct measurements. The emissions from the Toluca Valley are rather large and they could affect the air quality of Mexico City Valley. The air masses interchange between those two valleys is not very well understood; however, based on the measurements obtained during the 3 months campaign we looked carefully at the daily variability of the wind finding a clear signal for mountain-valley breeze. The ventilation coefficient is estimated and the correlations with the concentrations at the 4 locations and in a far away station in Mexico City are addressed in this work. Finally, we discuss the implication of the ventilation capacity in air quality for the system of Valleys that include Mexico City.

  4. Air quality modeling in the Valley of Mexico: meteorology, emissions and forecasting

    Science.gov (United States)

    Garcia-Reynoso, A.; Jazcilevich, A. D.; Diaz-Nigenda, E.; Vazquez-Morales, W.; Torres-Jardon, R.; Ruiz-Suarez, G.; Tatarko, J.; Bornstein, R.

    2007-12-01

    The Valley of Mexico presents important challenges for air quality modeling: complex terrain, a great variety of anthropogenic and natural emissions sources, and high altitude and low latitude increasing the amount of radiation flux. The modeling group at the CCA-UNAM is using and merging state of the art models to study the different aspects that influence the air quality phenomenon in the Valley of Mexico. The air quality model MCCM that uses MM5 as its meteorological input has been a valuable tool to study important features of the complex and intricate atmospheric flows on the valley, such as local confluences and vertical fumigation. Air quality modeling has allowed studying the interaction between the atmospheres of the valleys surrounding the Valley of Mexico, prompting the location of measurement stations during the MILAGRO campaign. These measurements confirmed the modeling results and expanded our knowledge of the transport of pollutants between the Valleys of Cuernavaca, Puebla and Mexico. The urban landscape of Mexico City complicates meteorological modeling. Urban-MM5, a model that explicitly takes into account the influence of buildings, houses, streets, parks and anthropogenic heat, is being implemented. Preliminary results of urban-MM5 on a small area of the city have been obtained. The current emissions inventory uses traffic database that includes hourly vehicular activity in more than 11,000 street segments, includes 23 area emissions categories, more than 1,000 industrial sources and biogenic emissions. To improve mobile sources emissions a system consisting of a traffic model and a car simulator is underway. This system will allow for high time and space resolution and takes into account motor stress due to different driving regimes. An important source of emissions in the Valley of Mexico is erosion dust. The erosion model WEPS has been integrated with MM5 and preliminary results showing dust episodes over Mexico City have been obtained. A

  5. Quaternary Geochronology, Paleontology, and Archaeology of the Upper San Pedro River Valley, Sonora, Mexico

    Science.gov (United States)

    Gaines, E. P.

    2013-12-01

    This poster presents the results of multi-disciplinary investigations of the preservation and extent of Quaternary fossil-bearing strata in the San Pedro River Valley in Sonora, Mexico. Geologic deposits in the portions of the San Pedro Valley in southern Arizona contain one of the best late Cenozoic fossil records known in North America and the best record of early humans and extinct mammals on the continent. The basin in the U.S. is one of the type locations for the Blancan Land Mammal Age. Hemiphilian and Irvingtonian fossils are common. Rancholabrean remains are widespread. Strata in the valley adjacent to the international border with Mexico have yielded the densest concentration of archaeological mammoth-kill sites known in the western hemisphere. Despite more than 60 years of research in the U.S., however, and the fact that over one third of the San Pedro River lies south of the international boundary, little has been known about the late Cenozoic geology of the valley in Mexico. The study reported here utilized extensive field survey, archaeological documentation, paleontological excavations, stratigraphic mapping and alluvial geochronology to determine the nature and extent of Quaternary fossil-bearing deposits in the portions of the San Pedro Valley in Sonora, Mexico. The results demonstrate that the Plio-Pleistocene fossil -bearing formations known from the valley in Arizona extend into the uppermost reaches of the valley in Mexico. Several new fossil sites were discovered that yielded the remains of Camelids, Equus, Mammuthus, and other Proboscidean species. Late Pleistocene archaeological remains were found on the surface of the surrounding uplands. AMS radiocarbon dating demonstrates the widespread preservation of middle- to late- Holocene deposits. However, the late Pleistocene deposits that contain the archaeological mammoth-kill sites in Arizona are absent in the valley in Mexico, and are now known to be restricted to relatively small portions of

  6. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity

    Energy Technology Data Exchange (ETDEWEB)

    Montelongo-Reyes, M.M.; Otazo-Sánchez, E.M.; Romo-Gómez, C.; Gordillo-Martínez, A.J.; Galindo-Castillo, E.

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO{sub 2} emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO{sub 2} sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO{sub 2} gas emissions were also significant, particularly SO{sub 2} (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. - Highlights: • First GHG & black carbon inventory for Mezquital Valley: Mexico City energy supplier • Energy industries caused the largest CO{sub 2} and SO{sub 2} emissions from residual fuel oil. • Diesel

  7. Seed production and quality of maize in High Valleys of Mexico.

    Directory of Open Access Journals (Sweden)

    Juan Virgen-Vargas

    2015-12-01

    Full Text Available The objective of this study was to increase the productivity of maize in High Valleys of Mexico, at the Valley of México and Bajio Experimental Stations of the National Institute for Forestry, Agriculture and Livestock Research (INIFAP. The following activities were carried out: production of registered seed to strengthen seed micro- enterprises of national capital, quality evaluation of certified seed, and generation of production technology. Between 2005 and 2013, 46.71 tons of registered seed of the hybrids parents: H-40, H-48, H-50, H-52, H-66, H-70 and H-161, and the varieties: VS-22, V-54A and V-55A were produced and sold to 31 seed producers in the Estado de Mexico, Tlaxcala, Puebla, Hidalgo, Morelos, Guanajuato, Michoacan, and Jalisco; that satisfied 60 % of demand per year (8.68 t. In 2013 and 2014, agreements were signed between INIFAP and four micro-enterprises to produce registered seeds. The certified seed produced by companies reached certification standards, germination percentage ≥ 85, 98% pure seed and less than 2% inert matter; test weight between 72 and 78 kg/hl, thousand seed weight between 288 and 361 g and genetic quality between 96 and 98 % of the true type plants. The study identified information about locations, potential yields, population density, and planting dates for the production of parents, lines and single crosses, in the Estado de Mexico and Tlaxcala.

  8. Elemental composition of the PM10 fraction in the Mezquital Valley, Mexico

    International Nuclear Information System (INIS)

    Beltran-Hernandez, I.; Martinez-Resendiz, G.; Solis Rosales, C.; Ramirez, A.; Sastre Conde, I.

    2009-01-01

    The Mezquital Valley has been receiving for nearly 100 years the residual waters of Mexico City to produce corn, alfalfa, oat, beans and barley among others. The information generated on the metal concentration in water, soils and agricultural products is vast. There are nevertheless limit's studies of other sources of heavy metal, like atmospheric wastes. (Author)

  9. New information on regional subsidence and soil fracturing in Mexico City Valley

    Directory of Open Access Journals (Sweden)

    G. Auvinet

    2015-11-01

    Full Text Available In this paper, updated information about regional subsidence in Mexico City downtown area is presented. Data obtained by R. Gayol in 1891, are compared with information obtained recently from surveys using the reference points of Sistema de Aguas de la Ciudad de México (2008 and on the elevation of a cloud of points on the ground surface determined using Light Detection and Ranging (LiDAR technology. In addition, this paper provides an overview of recent data obtained from systematic studies focused on understanding soil fracturing associated with regional land subsidence and mapping of areas susceptible to cracking in Mexico City Valley.

  10. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity.

    Science.gov (United States)

    Montelongo-Reyes, M M; Otazo-Sánchez, E M; Romo-Gómez, C; Gordillo-Martínez, A J; Galindo-Castillo, E

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO2 emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO2 sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO2 gas emissions were also significant, particularly SO2 (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Elemental composition of the PM{sub 1}0 fraction in the Mezquital Valley, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Beltran-Hernandez, I.; Martinez-Resendiz, G.; Solis Rosales, C.; Ramirez, A.; Sastre Conde, I.

    2009-07-01

    The Mezquital Valley has been receiving for nearly 100 years the residual waters of Mexico City to produce corn, alfalfa, oat, beans and barley among others. The information generated on the metal concentration in water, soils and agricultural products is vast. There are nevertheless limit's studies of other sources of heavy metal, like atmospheric wastes. (Author)

  12. InSAR to support sustainable urbanization over compacting aquifers: The case of Toluca Valley, Mexico

    Science.gov (United States)

    Castellazzi, Pascal; Garfias, Jaime; Martel, Richard; Brouard, Charles; Rivera, Alfonso

    2017-12-01

    This paper illustrates how InSAR alone can be used to delineate potential ground fractures related to aquifer system compaction. An InSAR-derived ground fracturing map of the Toluca Valley, Mexico, is produced and validated through a field campaign. The results are of great interest to support sustainable urbanization and show that InSAR processing of open-access Synthetic Aperture Radar (SAR) data from the Sentinel-1 satellites can lead to reliable and cost-effective products directly usable by cities to help decision-making. The Toluca Valley Aquifer (TVA) sustains the water needs of two million inhabitants living within the valley, a growing industry, an intensively irrigated agricultural area, and 38% of the water needs of the megalopolis of Mexico City, located 40 km east of the valley. Ensuring water sustainability, infrastructure integrity, along with supporting the important economic and demographic growth of the region, is a major challenge for water managers and urban developers. This paper presents a long-term analysis of ground fracturing by interpreting 13 years of InSAR-derived ground displacement measurements. Small Baseline Subset (SBAS) and Persistent Scatterer Interferometry (PSI) techniques are applied over three SAR datasets totalling 93 acquisitions from Envisat, Radarsat-2, and Sentinel-1A satellites and covering the period from 2003 to 2016. From 2003 to 2016, groundwater level declines of up to 1.6 m/yr, land subsidence up to 77 mm/yr, and major infrastructure damages are observed. Groundwater level data show highly variable seasonal responses according to their connectivity to recharge areas. However, the trend of groundwater levels consistently range from -0.5 to -1.5 m/yr regardless of the well location and depth. By analysing the horizontal gradients of vertical land subsidence, we provide a potential ground fracture map to assist in future urban development planning in the Toluca Valley.

  13. Factors affecting beef consumption in the valley of Mexico

    Directory of Open Access Journals (Sweden)

    Ricardo Tellez Delgado

    2015-10-01

    Full Text Available ABSTRACTThe objective of this study was to know the factors that determine the consumption of beef in the Metropolitan Area of the Valley of Mexico, using logit and probit modeling (nominal variable with 400 surveys. The results showed that significant variables that determine the probability of purchasing beef are schooling, number of members per family, meat preference, family income, and presence of disease in the individual. The largest marginal effects on the purchase decision were provided by the income and the meat preference variables, while the price was not significant. The main factors that determine the consumption of beef are schooling and the number of members in the family, while the meat preference and income are dismissed.

  14. Seeing Water in Early Twentieth-Century Mexico City: Henry Wellge's Perspective Plan of the City and Valley of Mexico, D.F. 1906

    OpenAIRE

    Widdifield, Stacie G.; Banister, Jeffrey M.

    2015-01-01

    We examine Henry Wellge's 1906 chromolithograph, Perspective Plan of the City and Valley of Mexico, D.F., a panoramic view that organizes the capital and its lacustrine environs through close up and distant perspectives. The Plan depicts a landscape integrated by canals, rivers, and lakes, recording a pivotal moment before modern hydraulic infrastructure would remove surface water from view. We thus interrogate this image as a visual register of hydraulic-control ideals in vogue around 1900, ...

  15. A diversity and conservation inventory of the Herpetofauna of the Cuautlapan Valley, Veracruz, Mexico.

    Science.gov (United States)

    DE LA Luz, Nelson M Ceron; Lemos-Espinal, Julio A; Smith, Geoffrey R

    2016-12-05

    We compiled an inventory of the amphibians and reptiles of the Cuautlapan Valley, Veracruz, Mexico based on field surveys and museum and literature records. We found a total of 78 species: 28 amphibians (6 Salamanders and 22 anurans); and 50 reptiles (three turtles, 18 lizards, and 29 snakes). These taxa represent 26 families (eight amphibian families, 18 reptile families) and 60 genera (19 amphibian genera, 41 reptile genera). Two of these species are not native to the area (Rhinoclemmys pulcherrima and Hemidactylus frenatus). According to the IUCN red list, five species are Critically Endangered, two are Endangered, four are Near Threatened, and four are Vulnerable. In the SEMARNAT (Secretaría del Medio Ambiente y Recursos Naturales) listing, one species is Endangered, eight species are Threatened, and 25 are Subject to Special Protection. Even though the Cuautlapan Valley is represented by a relatively small area it hosts a rich diversity of amphibian and reptile species, many of which are at risk and protected under Mexican law. This valley lies between the growing cities of Orizaba and Cordoba which have contributed to habitat degradation threatening the existence of the wildlife that occurs there.

  16. [Risk factors associated with work-related accidents in the construction industry in the Valley of Mexico].

    Science.gov (United States)

    Sarmiento-Salinas, Rodrigo; López-Rojas, Pablo; Marín-Cotoñieto, Irma Araceli; Godínez-Rocha, Arturo; Haro-García, Luis; Salinas-Tovar, Santiago

    2004-01-01

    Our aim was to describe construction-industry, work-related accident prevalence in, associated factors in, and potential impact on affiliated workers of the Mexican Institute of Social Security (Instituto Mexicano del Seguro Social, IMSS) in the Valley of Mexico. Prevalent cases in a retrospective case-control design. These include 385 construction-industry workers who were found to have construction work-related accidents in 2001. Controls comprised 385 active construction-industry workers without work-related accident background paired by gender, workplace, and worksite. Work-related accident prevalence in construction workers was 5.5%; most important risk factors and etiology fraction (Ef) included the following: age 16-20 years odds ratio, OR = 1.58, 95% confidence interval (95% CI) 1.40-10.7, p = 0.001, Ef 0.36; eventual insurance, OR = 3.7, 95% CI, 2.16-26.45, p = 0.001), Ef, 0.72, and no training for job, OR = 5.3, 95% CI, 4.9-69.2, p = 0.01), Ef: 0.81. Variables not showing significance were included salary, work shift, and workday. Work-related accident prevalence maintains its preponderance in the Valley of Mexico construction industry; identified risk factors are potentially modifiable, among which job training acquires unquestionable relevance.

  17. Arsenic drinking water exposure and urinary excretion among adults in the Yaqui Valley, Sonora, Mexico

    International Nuclear Information System (INIS)

    Meza, M.M.; Kopplin, M.J.; Burgess, J.L.; Gandolfi, A.J.

    2004-01-01

    The objective of this study was to determine arsenic exposure via drinking water and to characterize urinary arsenic excretion among adults in the Yaqui Valley, Sonora, Mexico. A cross-sectional study was conducted from July 2001 to May 2002. Study subjects were from the Yaqui Valley, Sonora, Mexico, residents of four towns with different arsenic concentrations in their drinking water. Arsenic exposure was estimated through water intake over 24 h. Arsenic excretion was assessed in the first morning void urine. Total arsenic concentrations and their species arsenate (As V), arsenite (As III), monomethyl arsenic (MMA), and dimethyl arsenic (DMA) were determined by HPLC/ICP-MS. The town of Esperanza with the highest arsenic concentration in water had the highest daily mean intake of arsenic through drinking water, the mean value was 65.5 μg/day. Positive correlation between total arsenic intake by drinking water/day and the total arsenic concentration in urine (r=0.50, P<0.001) was found. Arsenic excreted in urine ranged from 18.9 to 93.8 μg/L. The people from Esperanza had the highest geometric mean value of arsenic in urine, 65.1 μg/L, and it was statistically significantly different from those of the other towns (P<0.005). DMA was the major arsenic species in urine (47.7-67.1%), followed by inorganic arsenic (16.4-25.4%), and MMA (7.5-15%). In comparison with other reports the DMA and MMA distribution was low, 47.7-55.6% and 7.5-9.7%, respectively, in the urine from the Yaqui Valley population (except the town of Cocorit). The difference in the proportion of urinary arsenic metabolites in those towns may be due to genetic polymorphisms in the As methylating enzymes of these populations

  18. Arsenic drinking water exposure and urinary excretion among adults in the Yaqui Valley, Sonora, Mexico.

    Science.gov (United States)

    Meza, Maria Mercedes; Kopplin, Michael J; Burgess, Jefferey L; Gandolfi, A Jay

    2004-10-01

    The objective of this study was to determine arsenic exposure via drinking water and to characterize urinary arsenic excretion among adults in the Yaqui Valley, Sonora, Mexico. A cross-sectional study was conducted from July 2001 to May 2002. Study subjects were from the Yaqui Valley, Sonora, Mexico, residents of four towns with different arsenic concentrations in their drinking water. Arsenic exposure was estimated through water intake over 24 h. Arsenic excretion was assessed in the first morning void urine. Total arsenic concentrations and their species arsenate (As V), arsenite (As III), monomethyl arsenic (MMA), and dimethyl arsenic (DMA) were determined by HPLC/ICP-MS. The town of Esperanza with the highest arsenic concentration in water had the highest daily mean intake of arsenic through drinking water, the mean value was 65.5 microg/day. Positive correlation between total arsenic intake by drinking water/day and the total arsenic concentration in urine (r = 0.50, P < 0.001) was found. Arsenic excreted in urine ranged from 18.9 to 93.8 microg/L. The people from Esperanza had the highest geometric mean value of arsenic in urine, 65.1 microg/L, and it was statistically significantly different from those of the other towns (P < 0.005). DMA was the major arsenic species in urine (47.7-67.1%), followed by inorganic arsenic (16.4-25.4%), and MMA (7.5-15%). In comparison with other reports the DMA and MMA distribution was low, 47.7-55.6% and 7.5-9.7%, respectively, in the urine from the Yaqui Valley population (except the town of Cocorit). The difference in the proportion of urinary arsenic metabolites in those towns may be due to genetic polymorphisms in the As methylating enzymes of these populations.

  19. Water Supply Source Evaluation in Unmanaged Aquifer Recharge Zones: The Mezquital Valley (Mexico Case Study

    Directory of Open Access Journals (Sweden)

    Antonio Hernández-Espriú

    2016-12-01

    Full Text Available The Mezquital Valley (MV hosts the largest unmanaged aquifer recharge scheme in the world. The metropolitan area of Mexico City discharges ~60 m3/s of raw wastewater into the valley, a substantial share of which infiltrates into the regional aquifer. In this work, we aim to develop a comprehensive approach, adapted from oil and gas reservoir modeling frameworks, to assess water supply sources located downgradient from unmanaged aquifer recharge zones. The methodology is demonstrated through its application to the Mezquital Valley region. Geological, geoelectrical, petrophysical and hydraulic information is combined into a 3D subsurface model and used to evaluate downgradient supply sources. Although hydrogeochemical variables are yet to be assessed, outcomes suggest that the newly-found groundwater sources may provide a long-term solution for water supply. Piezometric analyses based on 25-year records suggest that the MV is close to steady-state conditions. Thus, unmanaged recharge seems to have been regulating the groundwater balance for the last decades. The transition from unmanaged to managed recharge is expected to provide benefits to the MV inhabitants. It will also be likely to generate new uncertainties in relation to aquifer dynamics and downgradient systems.

  20. Distribution of pesticides and PCBs in sediments of agricultural drains in the Culiacan Valley, Sinaloa, Mexico.

    Science.gov (United States)

    García-de la Parra, Luz María; Cervantes-Mojica, L Juleny; González-Valdivia, Carolina; Martínez-Cordero, Francisco J; Aguilar-Zárate, Gabriela; Bastidas-Bastidas, Pedro; Betancourt-Lozano, Miguel

    2012-10-01

    Agriculture is one of the most important economic activities in Sinaloa, Mexico. The Culiacan Valley is an extensive agricultural region characterized by a variety of crops with high-yield productions. In this study, concentrations of organochlorine (OCPs) and organophosphorus (OPs) pesticides and polychlorobiphenyls (PCBs) were determined in sediments of the agricultural drainage system of Culiacan Valley. Overall, 32 compounds were detected, with concentrations widely ranging from 0.03 to 1 294 ng g(-1) dry weight. OCP concentrations (15) ranged from 0.1 to 20.19 ng g(-1) dw. OP concentrations (8) ranged from 0.03 to 1294 ng g(-1) dw, and diazinon was the compound with the highest concentration. PCB concentrations were also determined and varied from 0.05 to 3.29 ng g(-1) dw. Other compounds detected included permethrin, triadimefon, and fipronil. The central zone registered the higher concentrations and the greatest number of compounds, which could be related to the occurrence of horticultural fields in this zone. According to sediment quality guidelines, the compounds exceeding the probable effect level were γ-HCH, p,p'-DDT and p,p'-DDE, while the pesticides above the maximum permissible concentration were endosulfan, azinphos methyl, diazinon, dichlorvos, and permethrin. Although Sinaloa is an important agricultural crop producer in northwest Mexico, there are not many studies dealing with pesticide distribution in agricultural areas.

  1. Sahagún's "Florentine codex," a little known Aztecan natural history of the Valley of Mexico.

    Science.gov (United States)

    Reeves, Henry M

    2006-01-01

    Franciscan missionary Fray Bernardino de Sahagún arrived in New Spain (Mexico) in 1529 to proselytize Aztecs surviving the Conquest, begun by Hernán Cortés in 1519. About 1558 he commenced his huge opus "Historia general de las cosas de Nueva España" completed in Latin-Nahuatl manuscript in 1569. The best surviving version, the "Florentine Codex," 1579 in Spanish-Nahuatl, is the basis for the editions published since 1829. The first English translation was issued in 13 volumes between 1950 and 1982, and the first facsimile was published in 1979. Book 11, "Earthly things," is a comprehensive natural history of the Valley of Mexico based on pre-Cortésian Aztec knowledge. Sahagún's work, largely unknown among English-speaking biologists, is an untapped treasury of information about Aztecan natural history. It also establishes the Aztecs as the preeminent pioneering naturalists of North American, and Sahagún and his colleagues as their documentarians.

  2. Evolution of the knowledge system for agricultural development in the Yaqui Valley, Sonora, Mexico.

    Science.gov (United States)

    McCullough, Ellen B; Matson, Pamela A

    2016-04-26

    Knowledge systems-networks of linked actors, organizations, and objects that perform a number of knowledge-related functions that link knowledge and know how with action-have played a key role in fostering agricultural development over the last 50 years. We examine the evolution of the knowledge system of the Yaqui Valley, Mexico, a region often described as the home of the green revolution for wheat, tracing changes in the functions of critical knowledge system participants, information flows, and research priorities. Most of the knowledge system's key players have been in place for many decades, although their roles have changed in response to exogenous and endogenous shocks and trends (e.g., drought, policy shifts, and price trends). The system has been agile and able to respond to challenges, in part because of the diversity of players (evolving roles of actors spanning research-decision maker boundaries) and also because of the strong and consistent role of innovative farmers. Although the agricultural research agenda in the Valley is primarily controlled from within the agricultural sector, outside voices have become an important influence in broadening development- and production-oriented perspectives to sustainability perspectives.

  3. The population structure of Phytophthora infestans from the Toluca Valley of Central Mexico suggests genetic differentiation between populations from cultivated potato and wild Solanum spp.

    NARCIS (Netherlands)

    Flier, W.G.; Grünwald, N.J.; Kroon, L.P.N.M.; Sturbaum, A.K.; Bosch, van den G.B.M.; Garay-Serrano, E.; Lozoya-Saldaña, H.; Fry, W.E.; Turkensteen, L.J.

    2003-01-01

    The Population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected front cultivated potatoes and the native wild Solanum spp., S. demissum and S. xedinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and

  4. 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

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

    Directory of Open Access Journals (Sweden)

    E. Glowacka

    2015-11-01

    Full Text Available 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

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

    OpenAIRE

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

    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 abnormali...

  7. Updated comparison of groundwater flow model results and isotopic data in the Leon Valley, Mexico

    Science.gov (United States)

    Hernandez-Garcia, G. D.

    2015-12-01

    Northwest of Mexico City, the study area is located in the State of Guanajuato. Leon Valley has covered with groundwater its demand of water, estimated in 20.6 cubic meters per second. The constant increase of population and economic activities in the region, mainly in cities and automobile factories, has also a constant growth in water needs. Related extraction rate has produced an average decrease of approximately 1.0 m per year over the past two decades. This suggests that the present management of the groundwater should be checked. Management of groundwater in the study area involves the possibility of producing environmental impacts by extraction. This vital resource under stress becomes necessary studying its hydrogeological functioning to achieve scientific management of groundwater in the Valley. This research was based on the analysis and integration of existing information and the field generated by the authors. On the base of updated concepts like the geological structure of the area, the hydraulic parameters and the composition of deuterium-delta and delta-oxygen -18, this research has new results. This information has been fully analyzed by applying a groundwater flow model with particle tracking: the result has also a similar result in terms of travel time and paths derived from isotopic data.

  8. LCA of road infrastructure in Mexico City.

    NARCIS (Netherlands)

    Rosales Carreon, Jesus

    2007-01-01

    Vehicular traffic is a major problem in metropolitan areas and Mexico City is no exception. Located in a pollutant-trapping valley, Mexico City (one of the largest cities in the world) is famous for its size, its history, and the warmth of its people. Nev

  9. The removal of microorganisms and organic micropollutants from wastewater during infiltration to aquifers after irrigation of farmland in the Tula Valley, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Alma; Maya, Catalina [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 D.F. (Mexico); Gibson, Richard [Instituto de Geografia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 D.F. (Mexico); Jimenez, Blanca, E-mail: bjimenezc@iingen.unam.mx [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 D.F. (Mexico)

    2011-05-15

    The Tula Valley receives untreated wastewater from Mexico City for agricultural irrigation, half of which infiltrates to aquifers from where drinking water is extracted. Samples of wastewater and infiltrated water from three areas of the valley were analyzed for microorganisms, organic micropollutants, and some basic parameters. Concentrations of microorganisms in the infiltrated water were generally very low but the incidence of fecal coliforms (present in 68% of samples), somatic bacteriophages (36%), Giardia spp. (14%), and helminth eggs (8%) suggested a health risk. Organic micropollutants, often present at high concentrations in the wastewater, were generally absent from the infiltrated water except carbamazepine which was in 55% of samples (up to 193 ng/L). There was no correlation between carbamazepine concentrations and the presence of microorganisms but highest concentrations of carbamazepine and boron coincided. A treatment such as nanofiltration would be necessary for the infiltrated water to be a safe potable supply. - Highlights: > Wastewater from Mexico City used for crop irrigation infiltrates to aquifers. > Infiltration through the soil removes many contaminants. > Occasional contamination of infiltrated water with microorganisms occurs. > Carbamazepine is widely present in the infiltrated water. > Safe use of this water for drinking would need nanofiltration or another treatment. - Water extracted from aquifers fed by wastewater used for irrigation may contain microorganisms and persistent polar organic micropollutants and requires treatment to be a potable supply.

  10. The removal of microorganisms and organic micropollutants from wastewater during infiltration to aquifers after irrigation of farmland in the Tula Valley, Mexico

    International Nuclear Information System (INIS)

    Chavez, Alma; Maya, Catalina; Gibson, Richard; Jimenez, Blanca

    2011-01-01

    The Tula Valley receives untreated wastewater from Mexico City for agricultural irrigation, half of which infiltrates to aquifers from where drinking water is extracted. Samples of wastewater and infiltrated water from three areas of the valley were analyzed for microorganisms, organic micropollutants, and some basic parameters. Concentrations of microorganisms in the infiltrated water were generally very low but the incidence of fecal coliforms (present in 68% of samples), somatic bacteriophages (36%), Giardia spp. (14%), and helminth eggs (8%) suggested a health risk. Organic micropollutants, often present at high concentrations in the wastewater, were generally absent from the infiltrated water except carbamazepine which was in 55% of samples (up to 193 ng/L). There was no correlation between carbamazepine concentrations and the presence of microorganisms but highest concentrations of carbamazepine and boron coincided. A treatment such as nanofiltration would be necessary for the infiltrated water to be a safe potable supply. - Highlights: → Wastewater from Mexico City used for crop irrigation infiltrates to aquifers. → Infiltration through the soil removes many contaminants. → Occasional contamination of infiltrated water with microorganisms occurs. → Carbamazepine is widely present in the infiltrated water. → Safe use of this water for drinking would need nanofiltration or another treatment. - Water extracted from aquifers fed by wastewater used for irrigation may contain microorganisms and persistent polar organic micropollutants and requires treatment to be a potable supply.

  11. Reproductive biology of Ferocactus recurvus (Mill.) Borg subsp. recurvus (Cactaceae) in the Tehuacán-Cuicatlán Valley, Mexico.

    Science.gov (United States)

    Córdova-Acosta, E; Zavala-Hurtado, J A; Golubov, J; Casas, A

    2017-09-01

    Mexico has one of the highest diversities of barrel cacti species worldwide; however, all are threatened and require conservation policies. Information on their reproductive biology is crucial, but few studies are available. Ferocactus recurvus subsp. recurvus is a barrel cactus endemic to the Tehuacán-Cuicatlán Valley. Our research aimed to characterise its floral and pollination biology. We hypothesised bee pollination, as suggested by its floral morphology and behaviour, and self-incompatibility, like most barrel cacti studied. Three study sites were selected in the semiarid Zapotitlán Valley, Mexico. We examined 190 flowers from 180 plants to determine: morphometry and behaviour of flowers, flower visitors and probable pollinators, and breeding system. Flowers showed diurnal anthesis, lasting 2-5 days, the stigma being receptive on day 2 or 3 after the start of anthesis. Flowers produced scarce/no nectar and main visitors were bees (Apidae), followed by flies (Muscidae), ants (Formicidae), thrips (Thripidae) and hummingbirds (Throchilidae); however, only native bees and occasionally wasps contacted the stigma and anthers. Pollination experiments revealed that this species is self-incompatible and xenogamous. In natural conditions, fruit set was 60% and cross-pollination fruit set was 100%. Percentage seed germination resulting from cross-pollination was higher than in the control treatment. Our results provide ecological information for conservation programmes to ensure a high probability of breeding and seed production in natural populations of F. recurvus. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  12. Hydrological Responses of Weather Conditions and Crop Change of Agricultural Area in the Rincon Valley, New Mexico

    Science.gov (United States)

    Ahn, S.; Sheng, Z.; Abudu, S.

    2017-12-01

    Hydrologic cycle of agricultural area has been changing due to the impacts of climate and land use changes (crop coverage changes) in an arid region of Rincon Valley, New Mexico. This study is to evaluate the impacts of weather condition and crop coverage change on hydrologic behavior of agricultural area in Rincon Valley (2,466km2) for agricultural watershed management using a watershed-scale hydrologic model, SWAT (Soil and Water Assessment Tool). The SWAT model was developed to incorporate irrigation of different crops using auto irrigation function. For the weather condition and crop coverage change evaluation, three spatial crop coverages including a normal (2008), wet (2009), and dry (2011) years were prepared using USDA crop data layer (CDL) for fourteen different crops. The SWAT model was calibrated for the period of 2001-2003 and validated for the period of 2004-2006 using daily-observed streamflow data. Scenario analysis was performed for wet and dry years based on the unique combinations of crop coverages and releases from Caballo Reservoir. The SWAT model simulated the present vertical water budget and horizontal water transfer considering irrigation practices in the Rincon Valley. Simulation results indicated the temporal and spatial variability for irrigation and non-irrigation seasons of hydrologic cycle in agricultural area in terms of surface runoff, evapotranspiration, infiltration, percolation, baseflow, soil moisture, and groundwater recharge. The water supply of the dry year could not fully cover whole irrigation period due to dry weather conditions, resulting in reduction of crop acreage. For extreme weather conditions, the temporal variation of water budget became robust, which requires careful irrigation management of the agricultural area. The results could provide guidelines for farmers to decide crop patterns in response to different weather conditions and water availability.

  13. Numerical modeling of Etla Valley aquifer, Oax., Mexico: Evolution and remediation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Marquez, E. L; Martinez-Serrano, R. G; Chavez, R. E; Crusillo, Y [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico); Jimenez, G [Facultad de Ingenieria, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Camops-Enriquez, O [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico)

    2008-01-15

    Short-term evolution (for 2001, 2005 and 2015) for the shallow aquifer of Etla Valley, Oaxaca, southern Mexico, was simulated based in a 3D hydrological model elaborated from the available geological, geophysical, geochemical, and hydrologic parameters. The numerical simulations were based on Visual MODFLOW code. These simulations indicate that, if the actual extraction regime is maintained, the drawdown of the potentiometric surface will get worse to the SE of the study area (i. e. beneath Oaxaca city). The prevailing aquifer flow direction favors the ground water pollution by fertilizers and leakage from the sewage network (dumped to the Atoyac river). According to the numerical simulation, remediation of this situation is possible if the wells located in the neighborhood of Oaxaca City are relocated at the recharge zones (i. e. at the feet from Sierra de Juarez). This remediation scenario will allow a recovery of the drawdown of the potentiometric surface. [Spanish] Se presenta un modelo geohidrologico evolutivo 3D a corto plazo (para los anos 2001, 2005 y 2015) del acuifero somero del Valle de Etla, Oaxaca, sureste de Mexico, basado en los parametros disponibles de geologia, geofisica, geoquimica e hidrologia. Las simulaciones numericas fueron realizadas en Visual MODFLOW. Estas simulaciones indican que, si el actual regimen de extraccion es mantenido, el abatimiento de la superficie potenciometrica puede ser mayor en el SE del area de estudio (i. e. cerca de la ciudad de Oaxaca). La contaminacion por fertilizantes y por las fugas de drenaje es favorecida por la direccion de flujo imperante en el acuifero (vaciandose en el rio Atoyac). De acuerdo a las simulaciones numericas, existe una posible remediacion de este proceso, relocalizando los pozos situados en la ciudad de Oaxaca en las zonas de recarga (i. e. en las faldas de la Sierra de Juarez). Este escenario de remediacion permitiria una recuperacion en el nivel de la superficie potenciometrica.

  14. In depth analysis of the role of the mountain gap south of the Valley of Mexico on the air quality in Mexico City.

    Science.gov (United States)

    Gerardo Ruiz Suarez, Luis

    2010-05-01

    38 days of air quality observations in Tenango del Aire (TENAI), south of Mexico City during MILAGRO were analyzed. That site was managed by FQA-CCA-UNAM's team with a mobile laboratory equipped with standard air quality monitors: O3, NOx, NOy, CO, SO2 and surface meteorological parameters. Hosted additional instruments were: CH2O, column NO2 (DOAS), backscatter (Lidar) and pilot balloons. Also, an ultra light plane from IMK-IFU, equipped with O3, PM10, CN, Dew Point monitors flew around the Popocatepetl and Iztaccihuatl volcanoes and above of TENAI some days during MILAGRO. Atop of TENAI, the ultra light descended in spiral until near ground and ascended to resume its path. In addition to these measurements, UNAM team ran air quality numerical simulations using the Mesoscale Climate and Chemistry Model (MCCM) and an online coupled Wind Erosion Processor to MCCM we call WEPS-MCCM. The combined observations on the ground, the ultra light plane and the models results enabled us to carry out an in depth analysis of air quality in such important region south of Mexico City. Comparison were made with the episodes classification proposed by De Foy; Ozone North and South, Convection North and South, Cold Surge and South Venting to characterize dynamics in the Valley of Mexico. The aim was to define how well connected is TENAI with the air quality network in the MCMA. The influence of the mountain gap on ozone and PM10 levels in Mexico City is analyzed by episode type. Also, the impact of the mega city of Mexico on the nearby region to the south can be understood by observations in TENAI. More polluted episode types in TENAI are those called: Cold Surge, Ozone South and South Venting due to a wind shift occurring in early afternoon that brings back polluted air that was drained south during the morning and returns back to TENAI rich in aged air parcels. March 17 was chosen to show the integrated analysis of all variables observed and modeled (MCCM) in TENAI. In that day

  15. Mitigating the Risk of Environmental Hazards in Mexico

    Science.gov (United States)

    2011-10-28

    wildfires.9 Infectious hazards in Mexico pose an intermediate risk of disease and include food or waterborne illness, hepatitis, dengue fever , Valley Fever ...the type of health threat that is posed. 12 Nanotechnology: Within the Latin American region , Brazil , Argentina and Mexico are leaders in...07/25/ dengue -on-the-loose/ (accessed 11 October 2011). 41. Environmental Protection Agency, State of the Border Region Indicators Report 2005, EPA

  16. A skin test survey of valley fever in Tijuana, Mexico.

    Science.gov (United States)

    Fredrich, B E

    1989-01-01

    Results of a study of the prevalence of valley fever among 1128 residents of Tijuana, Baja California are presented. Children from primary and middle schools (n = 497) and adults from technical institutes and maquiladoras (assembly plants) were tested for reaction to both spherulin and coccidioidin during 1985-1986, and they completed a questionnaire containing 23 variables on their socio-environment. Place of residence was mapped. The population sampled is largely middle class. Discriminant analysis indicates the distribution of positive cases is not clustered, nor can it be correlated with geomorphic factors such as mesa tops, canyons, or valley bottoms.

  17. Quaternary volcanism near the Valley of Mexico: implications for subduction zone magmatism and the effects of crustal thickness variations on primitive magma compositions

    Science.gov (United States)

    Wallace, Paul J.; Carmichael, Ian S. E.

    The Valley of Mexico and surrounding regions of Mexico and Morelos states in central Mexico contain more than 250 Quaternary eruptive vents in addition to the large, composite volcanoes of Popocatépetl, Iztaccíhuatl, and Nevado de Toluca. The eruptive vents include cinder and lava cones, shield volcanoes, and isolated andesitic and dacitic lava flows, and are most numerous in the Sierra Chichináutzin that forms the southern terminus of the Valley of Mexico. The Chichináutzin volcanic field (CVF) is part of the E-W-trending Mexican Volcanic Belt (MVB), a subduction-related volcanic arc that extends across Mexico. The crustal thickness beneath the CVF ( 50km) is the greatest of any region in the MVB and one of the greatest found in any arc worldwide. Lavas and scoriae erupted from vents in the CVF include alkaline basalts and calc-alkaline basaltic andesites, andesites, and dacites. Both alkaline and calc-alkaline groups contain primitive varieties that have whole rock Mg#, MgO, and Ni contents, and liquidus olivine compositions (<=Fo90) that are close to those expected of partial melts from mantle peridotite. Primitive varieties also show a wide range of incompatible trace element abundances (e.g. Ba 210-1080ppm Ce 25-100ppm Zr 130-280ppm). Data for primitive calc-alkaline rocks from both the CVF and other regions of the MVB to the west are consistent with magma generation in an underlying mantle wedge that is depleted in Ti, Zr, and Nb and enriched in large ion lithophile (K, Ba, Rb) and light rare earth (La, Ce) elements. Extents of partial melting estimated from Ti and Zr data are lower for primitive calc-alkaline magmas in the CVF than for those from the regions of the MVB to the west where the crust is thinner. The distinctive major element compositions (low CaO and Al2O3, high SiO2) of the primitive calc-alkaline magmas in the CVF indicate a more refractory mantle source beneath this region of thick crust. In contrast, primitive alkaline magmas from the

  18. Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

    International Nuclear Information System (INIS)

    Juarez-Cossio, D.; Terreros, E.; Quiroz-Moreno, J.; Romero-Sanchez, S.; Calligaro, T.F.; Tenorio, D.; Jimenez-Reyes, M.; Los Rios, M. de

    2009-01-01

    The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purisima, both archaeological sites of La Sierra Gorda Valleys, Mexico, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraiso Queretaro, Ucareo Michoacan and mainly from Zacualtipan/Metzquititlan Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300-1500).

  19. Variación espacial y temporal de la diversidad de hormigas en el Jardín Botánico del valle de Zapotitlán de las Salinas, Puebla Spatial and temporal variation of the diversity ants in the Botanic Garden from Zapotitlán de las Salinas Valley, Puebla

    Directory of Open Access Journals (Sweden)

    Rafael Guzmán-Mendoza

    2010-08-01

    Full Text Available Debido al escaso conocimiento que se tiene de las hormigas de las zonas áridas de México, se evaluó la biodiversidad de este taxón en el Jardín Botánico de Zapotitlán de las Salinas, Puebla. Se realizaron 2 colectas, una en época de lluvias (agosto de 2004 y otra en la temporada de secas (febrero de 2005. En ambas ocasiones se seleccionaron 2 sitios contrastantes en estructura vegetal y se colocaron 10 trampas de caída para cada sitio. La captura fue más abundante en temporada de lluvias. El sitio con menor diversidad y cobertura vegetal mostró una mayor diversidad de hormigas durante el estudio. Comparado con otras zonas áridas de México, el valle de Zapotitlán de las Salinas resultó ser una de las zonas semiáridas con mayor riqueza en especies de hormigas; con 12 nuevos registros se incrementó a 27 el número de especies, sólo una por debajo de otras localidades cercanas al valle. Los datos sugieren que con un mayor esfuerzo de muestreo y la aplicación combinada de otras técnicas de recolección, la riqueza de especies en el área podría elevarse considerablemente.The knowledge about ants of arid zones of Mexico is very poor. For this reason we assessed the biodiversity of this taxon in 2 sites with different vegetation structure. Ten pitfall traps were placed in each site, and 2 surveys were conducted, 1 in August (rainy season, 2004 and another in February (dry season, 2005. The capture was more abundant in the rainy season; however, during the study, a higher ant diversity was observed in the site with low vegetation cover and few plant diversity. Compared with other arid zones of Mexico, the Zapotitlán de las Salinas Valley is the site with the highest ant species richness. The new records have increased richness to 27 ant species, which is very close to the number of species registered in other localities near Zapotitlan. Our data suggest that increasing sampling effort and application of different sampling

  20. Environmental pollution and health in the metropolitan zone of Mexico Valley

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Cabrera, L.; Ramirez, A.

    2002-01-01

    Concerned about pollution in the Metropolitan Zone of Mexico Valley and its effects on inhabitant's health, the Faculty of Chemistry has been performing the monitoring of radon levels and heavy metals in environmental samples, since 1992. Samples consisted in aerosol fillers classified as Total Suspended Particles (TSP) and Respirable Particles (PM10) as well as dry fallout. Surveys were carried out in several zones covering the MZMV and different seasons along successive years. Metallic elements were determined by Instrumental Neutron Activation Analysis (INAA), X-Ray Fluorescence (dispersive and total reflection) and other techniques. Simultaneously, TSP and PM10 were determined by gravimetry. Annual radon gas concentration was determined with passive electret system (type E-PERM) and short radon decay products with a continuous working level monitor. This work presents the distribution an evolution of metallic pollutants in the MZMV. The effective equivalent dose for radon, calculated by the measured annual mean values of Radon and its short decay products, are 1.233 mSvy -1 in good agreement with the world average reported by UNSCEAR of 1.3 mSvy -1 . Despite of substantial progress in elimination of Lead sources (primarily from the phase-out leaded gasoline and regulations to reduce motorized traffic as part of stricter environmental laws) well correlated with a dramatic diminution of 91% in the geometric mean (2.00 μg dL -1 compared with that of 1980, 22.2 μg dL -1 ), the risk of Lead exposure is stilI present. Besides, TSP and PM10 concentration continue at levels above annual average concentration specified in the Mexican Norm. It makes necessary the continuity in efforts targeted to diminish the pollution and also epidemiological studies to relate its effects on population health and suggest guidelines. (Author)

  1. Hazard maps of Colima volcano, Mexico

    Science.gov (United States)

    Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.

    2011-12-01

    Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events

  2. Early thinning experiments established by the Fort Valley Experimental Forest

    Science.gov (United States)

    Benjamin P. De Blois; Alex. J. Finkral; Andrew J. Sanchez Meador; Margaret M. Moore

    2008-01-01

    Between 1925 and 1936, the Fort Valley Experimental Forest (FVEF) scientists initiated a study to examine a series of forest thinning experiments in second growth ponderosa pine stands in Arizona and New Mexico. These early thinning plots furnished much of the early background for the development of methods used in forest management in the Southwest. The plots ranged...

  3. Finite source modelling of magmatic unrest in Socorro, New Mexico, and Long Valley, California

    Science.gov (United States)

    Fialko, Yuri; Simons, Mark; Khazan, Yakov

    2001-07-01

    We investigate surface deformation associated with currently active crustal magma bodies in Socorro, New Mexico, and Long Valley, California, USA. We invert available geodetic data from these locations to constrain the overall geometry and dynamics of the inferred deformation sources at depth. Our best-fitting model for the Socorro magma body is a sill with a depth of 19km, an effective diameter of 70km and a rate of increase in the excess magma pressure of 0.6kPayr-1. We show that the corresponding volumetric inflation rate is ~6×10-3km3yr-1, which is considerably less than previously suggested. The measured inflation rate of the Socorro magma body may result from a steady influx of magma from a deep source, or a volume increase associated with melting of the magma chamber roof (i.e. crustal anatexis). In the latter case, the most recent major injection of mantle-derived melts into the middle crust beneath Socorro may have occurred within the last several tens to several hundreds of years. The Synthetic Interferometric Aperture Radar (InSAR) data collected in the area of the Long Valley caldera, CA, between June 1996 and July 1998 reveal an intracaldera uplift with a maximum amplitude of ~11cm and a volume of 3.5×10-2km3. Modelling of the InSAR data suggests that the observed deformation might be due to either a sill-like magma body at a depth of ~12km or a pluton-like magma body at a depth of ~8km beneath the resurgent dome. Assuming that the caldera fill deforms as an isotropic linear elastic solid, a joint inversion of the InSAR data and two-colour laser geodimeter data (which provide independent constraints on horizontal displacements at the surface) suggests that the inferred magma chamber is a steeply dipping prolate spheroid with a depth of 7-9km and an aspect ratio in excess of 2:1. Our results highlight the need for large radar look angles and multiple look directions in future InSAR missions.

  4. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A.; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  5. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  6. Geologic framework for the assessment of undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic-Lower Cretaceous Cotton Valley Group, U.S. Gulf of Mexico region

    Science.gov (United States)

    Eoff, Jennifer D.; Dubiel, Russell F.; Pearson, Ofori N.; Whidden, Katherine J.

    2015-01-01

    The U.S. Geological Survey (USGS) is assessing the undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic–Lower Cretaceous Cotton Valley Group in onshore areas and State waters of the U.S. Gulf of Mexico region. The assessment is based on geologic elements of a total petroleum system. Four assessment units (AUs) are defined based on characterization of hydrocarbon source and reservoir rocks, seals, traps, and the geohistory of the hydrocarbon products. Strata in each AU share similar stratigraphic, structural, and hydrocarbon-charge histories.

  7. 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

  8. Arsenic Content of the Drinking Water Source, for the Guadiana Valley, Mexico; Contenido de arsenico en el agua potable de Valle del Guadiana, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon Herrera, Maria Teresa [Centro de Investigacion en Materiales Avanzados (Mexico); Flores Montenegro, Isela [Sistema Desentralizado de agua Potable y alcantarillado Durango (Mexico); Romero Navar, Pedro [Comision Nacional del Agua (Mexico); Martin Dominguez, Ignacio [Centro de Investigacion en Materiales Avanzados (Mexico); Trejo Vazquez, Rodolfo [Instituto Tecnologico de Aguascalientes (Mexico)

    2001-12-01

    In recent years, high levels of arsenic concentration have been detected in some drinking water sources of the Guadiana Valley (Durango and surrounding towns) in Mexico. These levels are above the limits recommended bye the world Health Organization (WHO) and the maximum levels allowed by the Mexican standards. due to the well.known toxicity of this element, this study set as its objective to determine in quantitative terms the arsenic content of the drinking water sources for the Guadiana Valley, as the first step in the way to solve environment problems, It was found that 59% of the sources in the south, northeast and Northwest zones of Durango exceed in 40% the maximum level established by Mexican standards for arsenic content. In the Guadiana towns, 48% of the sources surpass such levels even in 46%. If the maximum levels suggested bye the WHO are taken as the reference, then virtually all sources exceed such level. [Spanish] En los ultimos anos, en la region del valle de Gadiana (ciudad de Durango y poblados cercanos) se han detectado niveles de concentracion de arsenico (As) en algunos pozos de abastecimiento de agua potable que superan los limites recomendados por la Organizacion Mundial de la Salud(OMS) y el limite maximo permisible establecido por la legislacion mexicana. Dada la conocida toxicidad de dicho elemento, en el presente estudio se propuso determinar cuantitativamente el contenido de arsenico en los pozos de abastecimiento de agua potable del valle del Guadiana, como un primer paso hacia la solucion de la problematica ambiental. Se encontro que en la zona sureste, noroeste y noreste de la ciudad, en 59% de los pozos se excede hasta en 40% la concentracion de arsenico establecida como limite maximo por la legislacion mexicana. En las poblaciones del valle del Guadiana, 48% de los pozos superan los limites mencionados hasta en un 136%. Si se toma como referencia el limite maximo establecido por la OMS, practicamente todos los pozos exceden el

  9. Radon-in-soil concentration levels in Mexico

    International Nuclear Information System (INIS)

    Segovia, N.; Tamez, E.; Mena, M.

    1992-01-01

    Radon-in-soil surveys in Mexico have been carried out since 1974 both for uranium prospecting and to correlate mean values of the gas emanation with local telluric behaviour. The mapping covers the northern uranium mining region, the Mexican Neovolcanic Belt, the coastal areas adjacent to the zone of subduction of the Cocos Plate under the North American Plate, some of the active volcanoes of Southern Mexico and several sedimentary valleys in Central Mexico. Recording of 222 Rn alpha decay is systematically performed with LR115 track detectors. Using mean values averaged over different observation periods at fixed monitoring stations, a radon-in-soil map covering one third of the territory of Mexico is presented. The lowest mean values occur in areas associated with active volcanoes. The highest levels are found in uranium ore zones. Intermediate values are obtained in regions with enhanced hydrothermal activity and stations associated with intrusive rocks. (author)

  10. A checklist of the mammals (Mammalia) from Durango, western Mexico

    OpenAIRE

    García-Mendoza, Diego; López-González, Celia

    2013-01-01

    An updated list of the mammals of Durango state, Mexico was built from literature records and Museum specimens. A total of 139 species have been recorded, representing 28.3 % of the Mexican terrestrial mammals, and 25.1 % species more compared to the previous account. Two species have been extirpated from the state, 23 are endemic to Mexico. Four major ecoregions have been previously defined for the state, Arid, Valleys, Sierra, and Quebradas. Species richness is highest at the Quebradas, a t...

  11. Design and results of the Mariano Lake-Lake Valley drilling project, Northwestern New Mexico

    International Nuclear Information System (INIS)

    Kirk, A.R.; Huffman, A.C. Jr.; Zech, R.S.

    1986-01-01

    This drilling project included 12 holes along a north-south-trending line from Mariano Lake to Lake Valley, New Mexico, near the southern margin of the San Juan basin. Of a total 33,075 ft (10,088m) drilled, 4,550 ft (1,388m) were cored in the stratigraphic interval that included the basal part of the Dakota Sandstone, the Brushy Basin and Westwater Canyon Members of the Morrison Formation, and the upper part of the Recapture Member of the Morrison Formation. The project objectives were (1) to provide cores and geophysical logs for study of the sedimentology, petrography, geochemistry, and mineralization in the uranium-bearing Westwater Canyon Member; (2) to provide control for a detailed seismic study of Morrison stratigraphy and basement structures; (3) to define and correlate the stratigraphy of Cretaceous coal-bearing units; (4) to supply background data for studies of ground-water flow pattern and ground-water quality; and (5) to provide data to aid resource assessment or uranium and coal. The project design included selection of (1) drill-hole locations to cross known ore and depositional trends in the Morrison Formation; (2) a coring interval to include the uranium-bearing unit and adjacent units; geophysical logs for lithologic correlations, quantitative evaluation of uranium mineralization, qualitative detection of coal beds, preparation of synthetic seismograms, and magnetic susceptibility studies of alteration in the Morrison; and (3) a high-salinity mud program to enhance core recovery

  12. Modeling Dissolved Solids in the Rincon Valley, New Mexico Using RiverWare

    Science.gov (United States)

    Abudu, S.; Ahn, S. R.; Sheng, Z.

    2017-12-01

    Simulating transport and storage of dissolved solids in surface water and underlying alluvial aquifer is essential to evaluate the impacts of surface water operations, groundwater pumping, and climate variability on the spatial and temporal variability of salinity in the Rio Grande Basin. In this study, we developed a monthly RiverWare water quantity and quality model to simulate the both concentration and loads of dissolved solids for the Rincon Valley, New Mexico from Caballo Reservoir to Leasburg Dam segment of the Rio Grande. The measured flows, concentration and loads of dissolved solids in the main stream and drains were used to develop RiveWare model using 1980-1988 data for calibration, and 1989-1995 data for validation. The transport of salt is tracked using discretized salt and post-process approaches. Flow and salt exchange between the surface water and adjacent groundwater objects is computed using "soil moisture salt with supplemental flow" method in the RiverWare. In the groundwater objects, the "layered salt" method is used to simulate concentration of the dissolved solids in the shallow groundwater storage. In addition, the estimated local inflows under different weather conditions by using a calibrated Soil Water Assessment Tool (SWAT) were fed into the RiverWare to refine the simulation of the flow and dissolved solids. The results show the salt concentration and loads increased at Leasburg Dam, which indicates the river collects salts from the agricultural return flow and the underlying aquifer. The RiverWare model with the local inflow fed by SWAT delivered the better quantification of temporal and spatial salt exchange patterns between the river and the underlying aquifer. The results from the proposed modeling approach can be used to refine the current mass-balance budgets for dissolved-solids transport in the Rio Grande, and provide guidelines for planning and decision-making to control salinity in arid river environment.

  13. Fifteen years of Superfund at South Valley: Reengineering required

    International Nuclear Information System (INIS)

    Cormier, J.; Horak, F.

    1995-01-01

    It is no surprise to many of Superfund's practitioners that the law and its application are flawed. The South Valley Superfund Site in Albuquerque, New Mexico has not escaped Superfund's problems. The problems and issues arising out of the South Valley Superfund site have spurred the desire to seek a better way to administer and manage cleanup. This new method applies organizational and role changes that bring Superfund closer to an efficient business-like entity. This ''Reengineered'' Superfund strives for reorganization, contractor reduction, improved communication, reporting reduction, and teaming. In addition, modifications are made to the roles of regulators, potentially responsible parties (PRPs), and the public. Today the site encompasses roughly one square mile in area, includes six identified contaminant sources, and deals with solvent and petroleum by-product contamination

  14. Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico, and Texas; occurrence and distribution of selected pesticides and nutrients at selected surface-water sites in the Mesilla Valley, 1994-95

    Science.gov (United States)

    Healy, D.F.

    1996-01-01

    The Rio Grande Valley study unit of the U.S. Geological Survey National Water-Quality Assessment Program conducted a two-phase synoptic study of the occurrence and distribution of pesticides and nutrients in the surface water of the Mesilla Valley, New Mexico and Texas. Phase one, conducted in April-May 1994 during the high-flow irrigation season, consisted of a 6-week time- series sampling event during which 17 water-column samples were collected at 3 main-stem sites on the Rio Grande and a synoptic irrigation-run sampling event during which 19 water-column samples were collected at 7 main-stem sites, 10 drain sites, and 2 sites at the discharges of wastewater-treatment plants. Three samples are included in both the time-series and irrigation-run events. Phase two, conducted in January 1995 during the low-flow non-irrigation season, consisted of a non-irrigation synoptic sampling event during which 18 water-column samples were collected at seven main-stem sites, nine drain sites, and two sites at the discharges of wastewater-treatment plants and a bed- material sampling event during which 6 bed-material samples were collected at six sites near the mouths of drains that discharge to the Rio Grande. The 51 water-column samples were analyzed for 78 pesticides and metabolites and 8 nutrients along with other constituents. The six bed-material samples were analyzed for 21 pesticides and metabolites, gross polychlorinated biphenyls, and gross polychlorinated naphthalenes. The presence of dissolved pesticides in the surface water of the Mesilla Valley is erratic. A total of 100 detections of 17 different pesticides were detected in 44 of the water-column samples. As many as 38 percent of these detections may be attributed to pesticide use upstream from the valley or to nonagricultural pesticide use within the valley. There were 29 detections of 10 different pesticides in 17 samples during the irrigation run and 41 detections of 13 pesticides in 16 samples during the non

  15. Industrial subdivisions in Aguascalientes State [Mexico]: Valley Region, potential spaces for development in the 21st Century

    Directory of Open Access Journals (Sweden)

    Héctor Daniel García Díaz

    2014-04-01

    Full Text Available The planning policies of the Mexican urban development oriented to the industrial activities implemented regionally and locally, have responded in different ways. The commitment to the sector led to the need to regulate urban growth and development as a substantial factor in achieving government strategies in the search for equitable sharing of national wealth and potential. The publication in 1976 of the General Law of Human Settlements born with this fundamental purpose. Excessive administrative burden of the Mexican social property and the need to insert in an increasingly globalizing economic activities led, in 1992 and 1994, respectively, the amendments to the Land Act and the signing of the Free Trade Agreement between North America, Canada, United States and Mexico. In the West Central Region, consisting of the metropolitan areas of Guadalajara, Zacatecas, San Luis Potosi, Queretaro, Guanajuato and Aguascalientes, spatial area in which a third of the country's inhabitants is based, and hosts the 100% extension territorial state of Aguascalientes, have been exploited discontinuously the natural and man-made resources available in the area. In the Valley of Aguascalientes, north-south strip of the state territory, have been authorized industrial subdivisions under plans and urban development programs that have accelerated or inhibited impulses, according to the vision and expectations of government power in turn; the different rhythms and changes of strategy applied to organize the disorder potential of the rural and urban environment express divergences in the reaches of consolidation and longed purposes. Research indicates and identifies the dynamics with which the last eight administrations of the Mexican State have acted in shaping the industrial potential of the Valley, which the south side hosts industrial city, Nissan I, Nissan II and Automotive Logistics Industrial Park, industrial settlements seeking to consolidate the region

  16. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 25. Summary of Results and Baseline and Pre-Mining Ground-Water Geochemistry, Red River Valley, Taos County, New Mexico, 2001-2005

    Science.gov (United States)

    Nordstrom, D. Kirk

    2008-01-01

    Active and inactive mine sites are challenging to remediate because of their complexity and scale. Regulations meant to achieve environmental restoration at mine sites are equally challenging to apply for the same reasons. The goal of environmental restoration should be to restore contaminated mine sites, as closely as possible, to pre-mining conditions. Metalliferous mine sites in the Western United States are commonly located in hydrothermally altered and mineralized terrain in which pre-mining concentrations of metals were already anomalously high. Typically, those pre-mining concentrations were not measured, but sometimes they can be reconstructed using scientific inference. Molycorp?s Questa molybdenum mine in the Red River Valley, northern New Mexico, is located near the margin of the Questa caldera in a highly mineralized region. The State of New Mexico requires that ground-water quality standards be met on closure unless it can be shown that potential contaminant concentrations were higher than the standards before mining. No ground water at the mine site had been chemically analyzed before mining. The aim of this investigation, in cooperation with the New Mexico Environment Department (NMED), is to infer the pre-mining ground-water quality by an examination of the geologic, hydrologic, and geochemical controls on ground-water quality in a nearby, or proximal, analog site in the Straight Creek drainage basin. Twenty-seven reports contain details of investigations on the geological, hydrological, and geochemical characteristics of the Red River Valley that are summarized in this report. These studies include mapping of surface mineralogy by Airborne Visible-Infrared Imaging Spectrometry (AVIRIS); compilations of historical surface- and ground- water quality data; synoptic/tracer studies with mass loading and temporal water-quality trends of the Red River; reaction-transport modeling of the Red River; environmental geology of the Red River Valley; lake

  17. An anthropological approach to the evaluation of preschool children exposed to pesticides in Mexico.

    OpenAIRE

    Guillette, E A; Meza, M M; Aquilar, M G; Soto, A D; Garcia, I E

    1998-01-01

    In this comparative study, we compensated for many of the known variables that influence children's growth and development by selecting two groups of 4-5-year-old Yaqui children who reside in the Yaqui Valley of northwestern Mexico. These children share similar genetic backgrounds, diets, water mineral contents, cultural patterns, and social behaviors. The major difference was their exposure to pesticides. Pesticides have been applied to the agricultural area of the valley since the late 1940...

  18. A survey of 222Rn in drinking water in mexico city

    International Nuclear Information System (INIS)

    Vasquez-Lopez, C.; Zendejas-Leal, B. E.; Golzarri, J. I.; Espinosa, G.

    2011-01-01

    In Mexico City there are more than 22 millions of inhabitants (10 in the metropolitan area and 12 in the suburban zone) exposed to drinking water. The local epidemiological authorities recognised that exposure to radon contaminated drinking water is a potential health hazard, as has been considered worldwide. The United States Environmental Protection Agency has proposed a limit of 11.1 Bq l -1 for the radon level in drinking water. In Mexico a maximum contamination level of radon in drinking water has not yet even considered. In this work, a 222 Rn study of drinking water in Mexico City has revealed a range of concentrations from background level to 3.8 Bq l -1 . 222 Rn was calculated using a portable degassing system (AquaKIT) associated with an AlphaGUARD measuring system. Samples from 70 wells of the water system of the south of the Valley Basin of Mexico City and from houses of some other political administrative divisions of Mexico City were taken. (authors)

  19. Human impacts on riparian ecosystems of the Middle Rio Grande Valley during historic times

    Science.gov (United States)

    Frank E. Wozniak

    1996-01-01

    The development of irrigation agriculture in historic times has profoundly impacted riparian ecosystems in the Middle Rio Grande Valley of New Mexico. A vital relationship has existed between water resources and settlement in the semi-arid Southwest since prehistoric times. Levels of technology have influenced human generated changes in the riparian ecosystems of the...

  20. Radon in soil concentration levels in Mexico

    International Nuclear Information System (INIS)

    Segovia, N.; Tamez, E.; Mena, M.

    1991-09-01

    Radon in soil surveys in Mexico have been carried out since 1974 both for uranium prospectus and to correlate mean values of the gas emanation with local telluric behaviour. The mapping includes the northern uranium mining region, the Mexican Neo volcanic Belt, the coastal areas adjacent to the zone of subduction of the Cocos Plate under the North American Plate, some of the active volcanoes of Southern Mexico and several sedimentary valleys in Central Mexico. Recording of 222 Rn alpha decay is systematically performed with LR115 track detectors. Using mean values averaged over different observation periods at fixed monitoring stations, a radon in soil map covering one third of the Mexican territory is presented. The lowest mean values have been found in areas associated with active volcanoes. The highest levels are found in uranium ore zones. Intermediate values are obtained in regions with enhanced hydrothermal activity and stations associated with intrusive rocks. (Author)

  1. National wildlife refuge management on the United States/Mexico border

    Science.gov (United States)

    William R. Radke

    2013-01-01

    Many conservation strategies have been developed by the U.S. Fish and Wildlife Service in cooperation with others to protect habitat and enhance the recovery of fish and wildlife populations in the San Bernardino Valley, which straddles Arizona, United States, and Sonora, Mexico. Habitats along this international border have been impacted by illegal activities,...

  2. Utilization of geothermal energy for agribusiness development in southwestern New Mexico. Technical completion report, July 19, 1978-May 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Landsford, R.R.; Abernathy, G.H.; Gollehon, N.R.

    1981-01-01

    An evaluation is presented of the direct heat utilization from geothermal resources for agribusiness uses in the Animas Valley, Southwestern New Mexico. The analysis includes an evaluation of the groundwater and geothermal resources in the Animas Valley, monitoring of an existing geothermal greenhouse, and evaluation of two potential agribusiness applications of geothermal waters (greenhouses and meat precooking).

  3. Anthropogenic changes and environmental degradation in pre-Hispanic and post-Colonial periods: soil erosion modelled with WEPP during Late Holocene in Teotihuacán Valley (central Mexico)

    Science.gov (United States)

    Lourdes González-Arqueros, M.; Mendoza Cantú, Manuel E.

    2015-04-01

    Land use changes and support practices are a worldwide significant issue in soil erosion and subsequently, land degradation. Anthropogenic changes, along different periods of the history in the last 2000 years in the Valley of Teotihuacan (central Mexico), highlight that soil erosion varies depending on how the management and the intensity of soil use is handled, considering the soils as a main resource. As a part of a broader effort to reconstruct the erosion dynamics in the Teotihuacán Valley through geoarchaeological approaches, this study apply a process-based watershed hydrology and upland erosion model, Water Erosion Prediction Project (WEPP). This research aims to contribute with insights through modelling and to recreate soil erosion and sedimentation dynamics in several historical periods with different environmental and anthropogenic scenarios. The Geo-spatial interface for WEPP (GeoWEPP) was used to characterize location of detachment, depositions and erosion predicted on the profile through time, based on current and hypothetical reconstructed conditions in the watershed. Climate, topography, soil and land use were used as inputs for the WEPP model to estimate runoff fluxes, soil loss rates, and sediment delivery ratio (SDR) for three historical scenarios: current period, reconstructed Teotihuacán period (AD 1-650), and reconstructed Aztec period (AD 1325-1520). Over a simulated and stablished timeframe for those social periods, the runoff, soil loss rate and SDR were estimated to be greater during the Aztec period. We assume that in general the climate conditions for this period were wetter, compared with present, in agreement with several authors that proposed climate reconstructions for the center of Mexico. It is also highlighted that support practices were more effective in this period. The next period with higher values is the current one, and fewer rates are estimated for the Teotihuacán period. This comparison release new arguments in the

  4. The Population Structure of Phytophthora infestans from the Toluca Valley of Central Mexico Suggests Genetic Differentiation Between Populations from Cultivated Potato and Wild Solanum spp.

    Science.gov (United States)

    Flier, Wilbert G; Grünwald, Niklaus J; Kroon, Laurens P N M; Sturbaum, Anne K; van den Bosch, Trudy B M; Garay-Serrano, Edith; Lozoya-Saldaña, Hector; Fry, William E; Turkensteen, Lod J

    2003-04-01

    ABSTRACT The population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected from cultivated potatoes and the native wild Solanum spp., S. demissum and S. xendinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus fingerprint genotype. Isolate samples were monomorphic for mtDNA haplotype because all isolates tested were of the Ia haplotype. A total of 158 multilocus AFLP genotypes were identified among the 170 P. infestans isolates included in this study. P. infestans populations sampled in the Toluca Valley in 1997 were highly variable and almost every single isolate represented a unique genotype based on the analysis of 165 AFLP marker loci. Populations of P. infestans collected from the commercial potato-growing region in the valley, the subsistence potato production area along the slopes of the Nevado de Toluca, and the native Solanum spp. on the forested slopes of the volcano showed a high degree of genetic diversity. The number of polymorphic loci varied from 20.0 to 62.4% for isolates collected from the field station and wild Solanum spp. On average, 81.8% (135) of the AFLP loci were polymorphic. Hetero-zygosity varied between 7.7 and 19.4%. Significant differentiation was found at the population level between strains originating from cultivated potatoes and wild Solanum spp. (P = 0.001 to 0.022). Private alleles were observed in individual isolates collected from all three populations, with numbers of unique dominant alleles varying from 9 to 16 for isolates collected from commercial potato crops and native Solanum spp., respectively. Four AFLP markers were exclusively found present in isolates collected from S. demissum. Indirect estimation of gene flow between populations indicated restricted gene flow between both P. infestans populations from cultivated potatoes and wild Solanum hosts. There was no evidence

  5. Study of Z > 18 elements concentration in tree rings from surroundings forests of the Mexico Valley using external beam PIXE

    International Nuclear Information System (INIS)

    Calva-Vazquez, G.; Razo-Angel, G.; Rodriguez-Fernandez, L.; Ruvalcaba-Sil, J.L.

    2006-01-01

    The concentration of elements with Z > 18 is measured in tree rings from forests at the surroundings of the Mexico Valley: El Chico National Park (ECP) and Desierto de los Leones National Park (DLP). The analysis was done by simultaneous PIXE-RBS using an external proton beam on tree rings of Pine and Sacred fir (species Pinus montezumae and Abies religiosa, respectively). This study provides information about the elemental concentration in trees of those parks during the years from 1965 to 2003. Typical elements such as K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Sr and Pb were detected using PIXE technique while the wood matrix composition (mainly C and O) was determined by RBS. In general, elemental contents present large variations but concentrations oscillate around the mean value during this period of time. Nevertheless, the measurements showed some trends for Fe and Zn in the tree-rings elemental composition that may be correlated to recent volcanic activities in the region. The low Mn contents indicate soil acidification in DLP from 1968 and the forest decline in ECP during the last 15 years

  6. A survey of ²²²Rn in drinking water in Mexico City.

    Science.gov (United States)

    Vázquez-López, C; Zendejas-Leal, B E; Golzarri, J I; Espinosa, G

    2011-05-01

    In Mexico City there are more than 22 millions of inhabitants (10 in the metropolitan area and 12 in the suburban zone) exposed to drinking water. The local epidemiological authorities recognised that exposure to radon contaminated drinking water is a potential health hazard, as has been considered worldwide. The United States Environmental Protection Agency has proposed a limit of 11.1 Bq l(-1) for the radon level in drinking water. In Mexico a maximum contamination level of radon in drinking water has not yet even considered. In this work, a (222)Rn study of drinking water in Mexico City has revealed a range of concentrations from background level to 3.8 Bq l(-1). (222)Rn was calculated using a portable degassing system (AquaKIT) associated with an AlphaGUARD measuring system. Samples from 70 wells of the water system of the south of the Valley Basin of Mexico City and from houses of some other political administrative divisions of Mexico City were taken.

  7. Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 & 2003 field campaigns

    Directory of Open Access Journals (Sweden)

    E. Velasco

    2007-01-01

    Full Text Available A wide array of volatile organic compound (VOC measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Four distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID, on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS, continuous real-time detection of olefins using a Fast Olefin Sensor (FOS, and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS. The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC was dominated by alkanes (60%, followed by aromatics (15% and olefins (5%. The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc. and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1,3-butadiene, benzene, toluene and xylenes, were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic in addition to meteorological processes. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other

  8. Factors Contributing to the Catastrophe in Mexico City During the Earthquake of September 19, 1985

    OpenAIRE

    Beck, James L.; Hall, John F.

    1986-01-01

    The extensive damage to high‐rise buildings in Mexico City during the September 19, 1985 earthquake is primarily due to the intensity of the ground shaking exceeding what was previously considered credible for the city by Mexican engineers. There were two major factors contributing to the catastrophe, resonance in the sediments of an ancient lake that once existed in the Valley of Mexico, and the long duration of shaking compared with other coastal earthquakes in the last 50 years. Both of th...

  9. Analysis of geophysical well logs from the Mariano Lake-Lake Valley drilling project, San Juan Basin, Northwestern New Mexico

    International Nuclear Information System (INIS)

    Scott, J.H.

    1986-01-01

    Geophysical well logs were obtained in eight deep holes drilled and cored by the U.S. Geological Survey to examine the geology of the Mariano Lake-Lake Valley area in the southern part of the San Juan basin, New Mexico. The logs were made to determine the petrophysical properties of the rocks penetrated by the holes, to aid in making stratigraphic correlations between the holes, and to estimate the grade of uranium enrichment in mineralized zones. The logs can be divided into six categories-nuclear, electric, sonic, magnetic, dipmeter, and borehole conditions. Examples of these logs are presented and related to lithological and petrophysical properties of the cores recovered. Gamma-ray and prompt fission neutron logs were used to estimate uranium grade in mineralized zones. Resistivity and spontaneous potential logs were used to make stratigraphic correlations between drill holes and to determine the variability of the sandstone:mudstone ratios of the major sedimentary units. In one drill hole a dipmeter log was used to estimate the direction of sediment transport of the fluvial host rock. Magnetic susceptibility logs provided supportive information for a laboratory study of magnetic mineral alteration in drill cores. This study was used to infer the geochemical and hydrologic environment associated with uranium deposition in the project area

  10. Mercury Speciation in Contaminated Soils from Old Mining Activities in Mexico Using a Chemical Selective Extraction

    OpenAIRE

    Gavilán-García, Irma; Santos-Santos, Elvira; Tovar-Gálvez, Luis R.; Gavilán-García, Arturo; Suárez, Sara; Olmos, Jesús

    2008-01-01

    Amalgamation was heavily used in mining since 1557 in Spanish Colonies. In Mexico and other parts of Latin-America, this process generated tailings which were left aside in the mine backyards. In the valley of Zacatecas, tailings were carried out of the mines due to the run-off from the mountains and contaminated most of the Zacatecan Valley which most important economic activity is agricultural (crop and livestock raising). The main concern in this area is the high level of total mercury fou...

  11. INAA of aerosol samples in Mexico City

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Navarrete, M.; Cabrera, L.; Riveroll, M.

    2000-01-01

    Total solid particles (TSP), respirable particles (RP) PM10 and 17 metallic pollutants were measured in dwellings in the Metropolitan Zone of Mexico Valley (MZMV) by gravimetry and instrumental neutron activation analysis (INAA). Monitoring was performed in Northeast, Center, Southeast and Southwest Zones in the winter and spring seasons. In general, the average concentration of contaminants (derived from industrial activities) that we have determined have increased with time. TSP and RP PM10 are often above the US and Mexican norms. (author)

  12. Mixing of groundwaters with uncertain end-members: Case study in the Tepalcingo-Axochiapan aquifer, Mexico

    NARCIS (Netherlands)

    Morales-Casique, E.

    2012-01-01

    Groundwater geochemical data from the northern portion of the Tepalcingo-Axochiapan Valley, in the state of Morelos, Mexico, are analyzed to improve the conceptual hydrogeologic model of the region. The geochemical data suggest that the chemical composition of groundwater is the result of a mixing

  13. Population structure of Phytophthora infestans in the Toluca Valley region of Central Mexico

    NARCIS (Netherlands)

    Grünwald, N.J.; Flier, W.G.; Sturbaum, A.K.; Garay-Serrano, E.; Bosch, van den G.B.M.; Smart, C.D.; Matuszak, J.M.; Turkensteen, L.J.; Fry, W.E.

    2001-01-01

    We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and

  14. Health-related quality of life in a binational population with diabetes at the Texas-Mexico border.

    Science.gov (United States)

    Mier, Nelda; Bocanegra-Alonso, Anabel; Zhan, Dongling; Zuniga, Miguel A; Acosta, Rosa I

    2008-03-01

    To examine physical and mental health domains of health-related quality of life (HRQL) in a binational adult population with type 2 diabetes at the Texas-Mexico border, and to explore individual and social correlates to physical and mental health status. Adults 18 years and older with type 2 diabetes residing in the South Texas Lower Rio Grande Valley and in Reynosa, Tamaulipas, Mexico, were recruited using a convenience sampling technique and interviewed face-to-face with a structured survey. HRQL was measured using physical and mental health summary components of the Medical Outcomes Study Short Form. HRQL correlates included demographic characteristics, health factors, access to healthcare, and family support. Samples characteristics were compared using the Student's t-test or Mann-Whitney U test. Associations between dependent and independent variables were examined using unadjusted and adjusted (multiple variable) logistic regression models. There were no significant differences between Valley and Reynosa respondents in physical or mental health status scores. Valley participants with lower socioeconomic status and those perceiving their supportive relative's level of diabetes-related knowledge as "low" were more likely to report worse physical health than those lacking those characteristics. In the Reynosa group, lower physical health status was associated with duration of diabetes and insulin use. Both sample populations with clinical depressive symptoms were more likely to have worse physical and mental health than those without such symptoms. HRQL is an important outcome in monitoring health status. Understanding the levels and influences of HRQL in U.S.-Mexico border residents with diabetes may help improve diabetes management programs.

  15. Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Vlaming, V. de [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States)]. E-mail: vldevlaming@ucdavis.edu; DiGiorgio, C. [Department of Water Resources, P.O. Box 942836, Sacramento, CA 94236 (United States); Fong, S. [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States); Deanovic, L.A. [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States); Paz Carpio-Obeso, M. de la [Colorado River Basin Region Water Quality Control Board, 73-720 Fred Waring Drive, Suite 100, Palm Desert, CA 92260 (United States); Miller, J.L. [AQUA-Science, 17 Arboretum Drive, Davis, CA 95616 (United States); Miller, M.J. [AQUA-Science, 17 Arboretum Drive, Davis, CA 95616 (United States); Richard, N.J. [Division of Water Quality, State Water Resources Control Board, 1001 I Street, Sacramento, CA 95814 (United States)

    2004-11-01

    The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts. - Capsule: Organophosphorous insecticides in runoff water from the USA and Mexico have impacted rivers in the Imperial Valley, California.

  16. Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

    International Nuclear Information System (INIS)

    Vlaming, V. de; DiGiorgio, C.; Fong, S.; Deanovic, L.A.; Paz Carpio-Obeso, M. de la; Miller, J.L.; Miller, M.J.; Richard, N.J.

    2004-01-01

    The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts. - Capsule: Organophosphorous insecticides in runoff water from the USA and Mexico have impacted rivers in the Imperial Valley, California

  17. Natural selection and type 2 diabetes-associated mortality in an isolated indigenous community in the valley of Oaxaca, southern Mexico.

    Science.gov (United States)

    Little, Bertis B; Peña Reyes, Maria Eugenia; Malina, Robert M

    2017-03-01

    This study tests the hypothesis that natural selection is associated with type 2 diabetes (T2D)-associated mortality and fertility in a rural isolated Zapotec community in the Valley of Oaxaca, southern Mexico. Mortality data and related demographic and genealogic information were linked with data for fertility, prereproductive mortality and family history of mortality attributed to T2D. Physician verified T2D mortality (n = 27) between 1980 and 2009 and imputed T2D (n = 70) from cardiovascular mortality (68% random sample) and renal failure (44% random sample). Bootstrapping was used to obtain a robust variance estimate in survival analysis and multivariate analysis of variance. Estimated maximum natural selection by Crow's Index occurred circa 1930 and was relaxed after this time in the study population. Cox-regression survival analysis of T2D mortality with covariates (family history of T2D, cardiovascular disease, renal failure) indicated a significant hazard ratio (HR = 5.95, 95% CI: 1.38-25.67, p natural selection decreased, and favored offspring survival of non-T2D descedants. The results indicated statistically significant directional selection against T2D and imputed T2D to this population isolate. © 2016 Wiley Periodicals, Inc.

  18. Karst in evaporites in southeastern New Mexico

    International Nuclear Information System (INIS)

    Bachman, G.O.

    1987-09-01

    Permian evaporites in southeastern New Mexico include gypsum, anhydrite, and salt, which are subject to both blanket and local, selective dissolution. Dissolution has produced many hundreds of individual karst features including collapse sinks, karst valleys, blind valleys, karst plains, caves, and breccia pipes. Dissolution began within some formations during Permian time and has been intermittent but continual ever since. Karst features other than blanket deposits of breccia are not preserved from the early episodes of dissolution, but some karst features preserved today - such as breccia pipes - are remnants of karst activity that was active at least as early as mid-Pleistocene time. Rainfall was much more abundant during Late Pleistocene time, and many features visible today may have been formed then. The drainage history of the Pecos River is related to extensive karstification of the Pecos Valley during mid-Pleistocene time. Large-scale stream piracy and dissolution of salt in the subsurface resulted in major shifts and excavations in the channel. In spite of intensive groundwater studies that have been carried out in the region, major problems in near-surface evaporite karst remain to be solved. Among these are determination of recharge areas and time of recharge. 109 refs., 31 figs., 1 tab

  19. Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico

    Science.gov (United States)

    Kraft, Kraig H.; Brown, Cecil H.; Nabhan, Gary P.; Luedeling, Eike; Luna Ruiz, José de Jesús; Coppens d’Eeckenbrugge, Geo; Hijmans, Robert J.; Gepts, Paul

    2014-01-01

    The study of crop origins has traditionally involved identifying geographic areas of high morphological diversity, sampling populations of wild progenitor species, and the archaeological retrieval of macroremains. Recent investigations have added identification of plant microremains (phytoliths, pollen, and starch grains), biochemical and molecular genetic approaches, and dating through 14C accelerator mass spectrometry. We investigate the origin of domesticated chili pepper, Capsicum annuum, by combining two approaches, species distribution modeling and paleobiolinguistics, with microsatellite genetic data and archaeobotanical data. The combination of these four lines of evidence yields consensus models indicating that domestication of C. annuum could have occurred in one or both of two areas of Mexico: northeastern Mexico and central-east Mexico. Genetic evidence shows more support for the more northern location, but jointly all four lines of evidence support central-east Mexico, where preceramic macroremains of chili pepper have been recovered in the Valley of Tehuacán. Located just to the east of this valley is the center of phylogenetic diversity of Proto-Otomanguean, a language spoken in mid-Holocene times and the oldest protolanguage for which a word for chili pepper reconstructs based on historical linguistics. For many crops, especially those that do not have a strong archaeobotanical record or phylogeographic pattern, it is difficult to precisely identify the time and place of their origin. Our results for chili pepper show that expressing all data in similar distance terms allows for combining contrasting lines of evidence and locating the region(s) where cultivation and domestication of a crop began. PMID:24753581

  20. Black bear population and connectivity in the Sky Islands of Mexico and the United States

    Science.gov (United States)

    N. E. Lara-Diaz; C. A. Lopez-Gonzalez; H. Coronel-Arellano; A. Gonzalez-Bernal

    2013-01-01

    The Sky Island region is a mountainous region surrounded by grasslands, deserts and intermountain valleys, located between Mexico and the United States. However, different land management and human impact can have an effect on its wildlife populations. Currently, the border wall poses an immediate threat to the survival of black bears (Ursus americanus), considered an...

  1. Valley-dependent band structure and valley polarization in periodically modulated graphene

    Science.gov (United States)

    Lu, Wei-Tao

    2016-08-01

    The valley-dependent energy band and transport property of graphene under a periodic magnetic-strained field are studied, where the time-reversal symmetry is broken and the valley degeneracy is lifted. The considered superlattice is composed of two different barriers, providing more degrees of freedom for engineering the electronic structure. The electrons near the K and K' valleys are dominated by different effective superlattices. It is found that the energy bands for both valleys are symmetric with respect to ky=-(AM+ξ AS) /4 under the symmetric superlattices. More finite-energy Dirac points, more prominent collimation behavior, and new crossing points are found for K' valley. The degenerate miniband near the K valley splits into two subminibands and produces a new band gap under the asymmetric superlattices. The velocity for the K' valley is greatly renormalized compared with the K valley, and so we can achieve a finite velocity for the K valley while the velocity for the K' valley is zero. Especially, the miniband and band gap could be manipulated independently, leading to an increase of the conductance. The characteristics of the band structure are reflected in the transmission spectra. The Dirac points and the crossing points appear as pronounced peaks in transmission. A remarkable valley polarization is obtained which is robust to the disorder and can be controlled by the strain, the period, and the voltage.

  2. Use of deuterium and oxygen-18 in hydrological problems at Delicias Valley, Chihuahua, Mexico

    International Nuclear Information System (INIS)

    Castillo C, R.; Morales, P.; Cortes, A.

    1983-01-01

    An initial study using stable isotopes at Delicias Valley, Chihuahua, is presented, where we found an aquifer with two kinds of waters, one of recent infiltration (highly fractionated) and another of more depleted isotope concentration representing precipitation before the construction of the dam and distribution channels. (author)

  3. First records of the Brown Creeper breeding along the middle Rio Grande in central New Mexico

    Science.gov (United States)

    Jean-Luc E. Cartron; David L. Hawksworth; Deborah M. Finch

    2008-01-01

    In New Mexico, the Brown Creeper (Certhia americana) typically breeds in montane coniferous forests ranging in elevation from 2100 to 3300 m (Ligon 1961, Hubbard 1978). Since 2003, however, we have also noted breeding in the riparian cottonwood forest (hereafter bosque) along the middle Rio Grande, in the south valley of Albuquerque, Bernalillo...

  4. Assessment of Spatial Variability of Heavy Metals in Metropolitan Zone of Toluca Valley, Mexico, Using the Biomonitoring Technique in Mosses and TXRF Analysis

    Directory of Open Access Journals (Sweden)

    Graciela Zarazúa-Ortega

    2013-01-01

    Full Text Available This study is aimed at assessing atmospheric deposition of heavy metals using the epiphytic moss genera Fabronia ciliaris collected from six urban sites in the Metropolitan Zone of the Toluca Valley in Mexico. The concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Pb were determined by total reflection X-ray fluorescence technique. Results show that the average metal concentration decrease in the following order: Fe (8207 mg/Kg > Ca (7315 mg/Kg > K (3842 mg/Kg > Ti (387 mg/Kg > Mn, Zn (191 mg/Kg > Sr (71 mg/Kg > Pb (59 mg/Kg > Cu, V (32 mg/Kg > Cr (24 mg/Kg > Rb (13 mg/Kg > Ni (10 mg/Kg. Enrichment factors show a high enrichment for Cr, Cu, Zn, and Pb which provides an evidence of anthropogenic impact in the industrial and urban areas, mainly due to the intense vehicular traffic and the fossil fuel combustion. Monitoring techniques in mosses have proved to be a powerful tool for determining the deposition of heavy metals coming from diverse point sources of pollution.

  5. Mineralogical Composition of the Mexican Ordinary Chondrite Type Meteorite: A Raman, Infrared and XRD Study

    Science.gov (United States)

    Ostrooumov, M.

    2016-08-01

    The Raman microprobe (RMP), infrared (IR) and XRD analysis have been applied to the examination of mineralogical composition of seven mexican meteorites: Aldama, Cosina, El Pozo, Escalon, Nuevo Mercurio,Pacula, Zapotitlan Salinas.

  6. Rebels and Transgressors. Among Whispers of Insurrection. The intendencia of Mexico, 1810-1814

    Directory of Open Access Journals (Sweden)

    María Antonieta Ilhui Pacheco Chávez

    2009-07-01

    Full Text Available The war of Independence created  an atmosphere of tension among the inhabitants of the Valley of Mexico. During the first years, the region's peoples sought the way to survive between two fires. Their discourse of submission  and loyalty,  as well as their “fooling  around” with the insurgents,  were some strategies of resistance and transgression. Eventually, war turned into another way of life. Thereafter,  merchandise  trade, kidnapping, corruption, and revenge among parishioners, priests and militiamen created a new kind of rebel. This paper examines the different phases that resistance and rebellion went through among the inhabitants of the Intendencia of Mexico during the war.

  7. Energy balance of the metropolitan zone of the valley of Mexico, methodology and the entailment energy-air quality; Balance de energia de la zona metropolitana del valle de Mexico metodologia y la vinculacion energia - calidad del aire

    Energy Technology Data Exchange (ETDEWEB)

    Bazan Navarrete, Gerardo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2001-07-01

    The present document raises a methodology for the elaboration of the Energy Balance of the Metropolitan Zone of the Valley of Mexico (ZMVM), in order to unify criteria and to facilitate the work of entities and investigators, mainly of those that require the entailment of energy and environment. The applied methodology, the consolidated format and the caloric unity facilitates the insertion of the Energy Balance of the ZMVM within the National Balance of Energy. The regional balances of energy have the intention of knowing the energy consumption patterns in the ZMVM and the indexes of energy intensity by sector. They establish the relationship of the indexes of energy intensity with the local and global air quality of the region, performing studies of incidence with the main polluting agents and with the greenhouse effect gases. [Spanish] El presente documento plantea una metodologia para la elaboracion del Balance de Energia de la Zona Metropolitana del Valle de Mexico (ZMVM), con el proposito de unificar criterios y facilitar el trabajo de organismos e investigadores, sobre todo de aquellos que requieren vincular energia y medio ambiente. La metodologia aplicad, el formato consolidado y la unidad calorica facilitan la insercion del Balance de Energia de la ZMVM dentro del Balance Nacional de Energia. Los balances regionales de energia tienen el proposito de conocer los patrones de consumo de energia en la ZMVM y los indices de intensidad energetica por sector. Establecen la relacion de los indices de intensidad energetica con la calidad del aire local y global de la region, realizando estudios de incidencia con los principales contaminantes y con los gases de efecto invernadero.

  8. New Insights Into Valley Formation and Preservation: Geophysical Imaging of the Offshore Trinity River Paleovalley

    Science.gov (United States)

    Speed, C. M.; Swartz, J. M.; Gulick, S. P. S.; Goff, J.

    2017-12-01

    The Trinity River paleovalley is an offshore stratigraphic structure located on the inner continental shelf of the Gulf of Mexico offshore Galveston, Texas. Its formation is linked to the paleo-Trinity system as it existed across the continental shelf during the last glacial period. Newly acquired high-resolution geophysical data have imaged more complexity to the valley morphology and shelf stratigraphy than was previously captured. Significantly, the paleo-Trinity River valley appears to change in the degree of confinement and relief relative to the surrounding strata. Proximal to the modern shoreline, the interpreted time-transgressive erosive surface formed by the paleo-river system is broad and rugose with no single valley, but just 5 km farther offshore the system appears to become confined to a 10 km wide valley structure before again becoming unconfined once again 30 km offshore. Fluvial stratigraphy in this region has a similar degree of complexity in morphology and preservation. A dense geophysical survey of several hundred km is planned for Fall 2017, which will provide unprecedented imaging of the paleovalley morphology and associated stratigraphy. Our analysis leverages robust chirp processing techniques that allow for imaging of strata on the decimeter scale. We will integrate our geophysical results with a wide array of both newly collected and previously published sediment cores. This approach will allow us to address several key questions regarding incised valley formation and preservation on glacial-interglacial timescales including: to what extent do paleo-rivers remain confined within a single broad valley structure, what is the fluvial systems response to transgression, and what stratigraphy is created and preserved at the transition from fluvial to estuarine environments? Our work illustrates that traditional models of incised valley formation and subsequent infilling potentially fail to capture the full breadth of dynamics of past river

  9. Water-quality assessment of the Rio Grande Valley study unit, Colorado, New Mexico, and Texas: analysis of selected nutrient, suspended-sediment, and pesticide data

    Science.gov (United States)

    Anderholm, S.K.; Radell, M.J.; Richey, S.F.

    1995-01-01

    This report contains a summary of data compiled from sources throughout the Rio Grande Valley study unit of the National Water-Quality Assessment program. Information presented includes the sources and types of water-quality data available, the utility of water-quality data for statistical analysis, and a description of recent water-quality conditions and trends and their relation to natural and human factors. Water-quality data are limited to concentrations of selected nutrient species in surface water and ground water, concentrations of suspended sediment and suspended solids in surface water, and pesticides in surface water, ground water, and biota.The Rio Grande Valley study unit includes about 45,900 square miles in Colorado, New Mexico, and Texas upstream from the streamflow-monitoring station Rio Grande at El Paso, Texas. The area also includes the San Luis Closed Basin and the surface-water closed basins east of the Continental Divide and north of the United States-Mexico international border. The Rio Grande drains about 29,300 square miles in these States; the remainder of the study unit area is in closed basins. Concentrations of all nutrients found in surface-water samples collected from the Rio Grande, with the exception of phosphorus, generally remained nearly constant from the northernmost station in the study unit to Rio Grande near Isleta, where concentrations were larger by an order of magnitude. Total nitrogen and total phosphorus loads increased downstream between Lobatos, Colorado, and Albuquerque, New Mexico. Nutrient concentrations remained elevated with slight variations until downstream from Elephant Butte Reservoir, where nutrient concentrations were lower. Nutrient concentrations then increased downstream from the reservoir, as evidenced by elevated concentrations at Rio Grande at El Paso, Texas.Suspended-sediment concentrations were similar at stations upstream from Otowi Bridge near San Ildefonso, New Mexico. The concentration and

  10. 77 FR 33237 - Saline Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National...

    Science.gov (United States)

    2012-06-05

    ... Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National Park, Inyo... an Environmental Impact Statement for the Saline Valley Warm Springs Management Plan, Death Valley... analysis process for the Saline Valley Warm Springs Management Plan for Death Valley [[Page 33238...

  11. Bacteriological quality of crops irrigated with wastewater in the Xochimilco plots, Mexico City, Mexico.

    Science.gov (United States)

    Rosas, I; Báez, A; Coutiño, M

    1984-05-01

    Xochimilco county plots (Mexico City), one of the most fertile agricultural areas in the Valley of Mexico, produce a large portion of the fresh vegetables consumed in the city. These plots are generally irrigated with domestic wastewater, and for this reason, it was deemed important to examine and evaluate the bacteriological quality of the water, soil, and vegetables from these plots that are harvested and marketed. The soils were also examined for the classical parameters such as nitrates, ammonia, etc., and organic matter and texture. The crops selected for this study were radishes, spinach, lettuce, parsley, and celery because they are usually consumed raw. The highest bacterial counts were encountered in leafy vegetables, i.e., spinach (8,700 for total coliform and 2,400 for fecal coliform) and lettuce (37,000 for total coliform and 3,600 for fecal coliform). Statistically significant differences in bacterial counts between rinsed and unrinsed edible portions of the crops were observed even in rinsed vegetables, and high densities of fecal coliform were detected, indicating that their consumption represents a potential health hazard. The total coliform values found in irrigation water ranged from 4 X 10(4) to 29 X 10(4), and for fecal coliform the values ranged from 5 X 10(2) to 30 X 10(2).

  12. Trend in Air Quality of Kathmandu Valley: A Satellite, Observation and Modelling Perspective

    Science.gov (United States)

    Mahapatra, P. S.; Praveen, P. S.; Adhikary, B.; Panday, A. K.; Putero, D.; Bonasoni, P.

    2016-12-01

    Kathmandu (floor area of 340 km2) in Nepal is considered to be a `hot spot' of urban air pollution in South Asia. Its structure as a flat basin surrounded by tall mountains provides a unique case study for analyzing pollution trapped by topography. Only a very small number of cities with similar features have been studied extensively including Mexico and Santiago-de-Chile. This study presents the trend in satellite derived Aerosol Optical Depth (AOD) from MODIS AQUA and TERRA (3x3km, Level 2) over Kathmandu from 2000 to 2015. Trend analysis of AOD shows 35% increase during the study period. Determination of the background pollution would reveal the contribution of only Kathmandu Valley for the observation period. For this, AOD at 1340m altitude outside Kathmandu, but nearby areas were considered as background. This analysis was further supported by investigating AOD at different heights around Kathmandu as well as determining AOD from CALIPSO vertical profiles. These analysis suggest that background AOD contributed 30% in winter and 60% in summer to Kathmandu Valley's observed AOD. Thereafter the background AOD was subtracted from total Kathmandu AOD to determine contribution of only Kathmandu Valley's AOD. Trend analysis of only Kathmandu Valley AOD (subtracting background AOD) suggested an increase of 50% during the study period. Further analysis of Kathmandu's visibility and AOD suggest profound role of background AOD on decreasing visibility. In-situ Black Carbon (BC) mass concentration measurements (BC being used as a proxy for surface observations) at two sites within Kathmandu valley have been analyzed. Kathmandu valley lacks long term trends of ambient air quality measurement data. Therefore, surface observations would be coupled with satellite measurements for understanding the urban air pollution scenario. Modelling studies to estimate the contribution of background pollution to Kathmandu's own pollution as well as the weekend effect on air quality will

  13. Mexico City air quality research initiative. Volume 2, Problem definition, background, and summary of prior research

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    Air pollution in Mexico City has increased along with the growth of the city, the movement of its population, and the growth of employment created by industry. The main cause of pollution in the city is energy consumption. Therefore, it is necessary to take into account the city`s economic development and its prospects when considering the technological relationships between well-being and energy consumption. Air pollution in the city from dust and other particles suspended in the air is an old problem. However, pollution as we know it today began about 50 years ago with the growth of industry, transportation, and population. The level of well-being attained in Mexico City implies a high energy use that necessarily affects the valley`s natural air quality. However, the pollution has grown so fast that the City must act urgently on three fronts: first, following a comprehensive strategy, transform the economic foundation of the city with nonpolluting activities to replace the old industries, second, halt pollution growth through the development of better technologies; and third, use better fuels, emission controls, and protection of wooded areas.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Idalia Jazmin Castañeda-Yslas

    2016-01-01

    Full Text Available 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.

  16. Comparative diet of three sympatric Sceloporus in the semiarid Zapotitlan Valley, Mexico Comparación de la dieta de tres especies simpátridas de Sceloporus en el valle semiárido de Zapotitlán, México

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Serrano-Cardozo

    2008-12-01

    Full Text Available Ecology, morphology, and phylogeny contribute to the organization of lizard assemblages; however, the number of lizard assemblages for which detailed knowledge of closely related sympatric species is available is limited. We studied the diet of 3 sympatric species of lizards (Sceloporus gadoviae, S. horridus, and S. jalapae from arid tropical scrub forest in Puebla, Mexico. These species prey primarily on arthropods, mostly termites, ants, and beetles. Spring and summer rains caused an increase in available prey biomass. However, lizards continued using the same resources throughout the study. These 3 species of Sceloporus are similar in their diet, especially the smaller bodied species, S. gadoviae and S. jalapae. Termites are a very important food for the 3 species throughout the year and are a major resource during the rainy season, which is not consistent with the hypothesis that many lizards eat termites only in the dry season.La ecología, morfología y la filogenia contribuyen a la organización de los ensambles de lagartijas. Sin embargo, son pocos los estudios detallados sobre la organización de estos ensambles y más aún, con especies simpátridas. Estudiamos la dieta, reproducción y dimorfismo sexual de 3 especies simpátridas de lagartijas (Sceloporus gadoviae, S. horridus, and S. jalapae de un matorral árido tropical en Puebla, México. Estas especies se alimentaron de artrópodos; principalmente de termitas, hormigas y escarabajos. Las lluvias de primavera y verano causaron un incremento en la biomasa de presas; sin embargo, las lagartijas continuaron usando los mismos recursos. Las lagartijas fueron especialistas consumiendo presas en relación a su abundancia. Las 3 especies fueron similares en su dieta, especialmente las especies pequeñas S. gadoviae y S. jalapae. Las termitas son un importante recurso para estas 3 especies durante el todo año y la principal fuente alimenticia en la estación lluviosa, lo cual no es

  17. Physical Exposure to Seismic Hazards of Health Facilities in Mexico City, Mexico

    Science.gov (United States)

    Rodriguez, S. M.; Novelo Casanova, D.

    2010-12-01

    Although health facilities are essential infrastructure during disasters and emergencies, they are also usually highly vulnerable installations in the case of the occurrence of large and major earthquakes. Hospitals are one of the most complex critical facilities in modern cities and they are used as first response in emergency situations. The operability of a hospital must be maintained after the occurrence of a local strong earthquake in order to satisfy the need for medical care of the affected population. If a health facility is seriously damaged, it cannot fulfill its function when most is needed. In this case, hospitals become a casualty of the disaster. To identify the level of physical exposure of hospitals to seismic hazards in Mexico City, we analyzed their geographic location with respect to the seismic response of the different type of soils of the city from past earthquakes, mainly from the events that occurred on September 1985 (Ms= 8.0) and April 1989 (Ms= 6.9). Seismic wave amplification in this city is the result of the interaction of the incoming seismic waves with the soft and water saturated clay soils, on which a large part of Mexico City is built. The clay soils are remnants of the lake that existed in the Valley of Mexico and which has been drained gradually to accommodate the growing urban sprawl. Hospital facilities were converted from a simple database of names and locations into a map layer of resources. This resource layer was combined with other map layers showing areas of seismic microzonation in Mexico City. This overlay was then used to identify those hospitals that may be threatened by the occurrence of a large or major seismic event. We analyzed the public and private hospitals considered as main health facilities. Our results indicate that more than 50% of the hospitals are highly exposed to seismic hazards. Besides, in most of these health facilities we identified the lack of preventive measures and preparedness to reduce their

  18. Electromagnetic surveys to detect clay-rich sediment in the Rio Grande inner valley, Albuquerque area, New Mexico

    Science.gov (United States)

    Bartolino, James R.; Sterling, Joseph M.

    2000-01-01

    Information on the presence of clay-rich layers in the inner-valley alluvium is essential for quantifying the amount of water transmitted between the Rio Grande and the Santa Fe Group aquifer system. This report describes a study that used electromagnetic surveys to provide this information. In the first phase of the study, electromagnetic soundings were made using time-domain and frequency-domain electro- magnetic methods. On the basis of these initial results, the time- domain method was judged ineffective because of cultural noise in the study area, so subsequent surveys were made using the frequency-domain method. For the second phase of the study, 31 frequency-domain electromagnetic surveys were conducted along the inner valley and parallel to the Rio Grande in the Albuquerque area in the spring and summer of 1997 to determine the presence of hydrologically significant clay-rich layers buried in the inner-valley alluvium. For this report, the 31 survey sections were combined into 10 composite sections for ease of interpretation. Terrain-conductivity data from the surveys were modeled using interpretation software to produce geoelectric cross sections along the survey lines. This modeling used lithologic logs from two wells installed near the survey lines: the Bosque South and Rio Bravo 5 wells. Because of cultural interference, location of the wells and soundings, complex stratigraphy, and difficulty interpreting lithology, such interpretation was inconclusive. Instead, a decision process based on modeling results was developed using vertical and horizontal dipole 40-meter intercoil spacing terrain-conductivity values. Values larger than or equal to 20 millisiemens per meter were interpreted to contain a hydrologically significant thickness of clay-rich sediment. Thus, clay-rich sediment was interpreted to underlie seven segments of the 10 composited survey lines, totaling at least 2,660 meters of the Rio Grande inner valley. The longest of these clay

  19. Valley polarization in bismuth

    Science.gov (United States)

    Fauque, Benoit

    2013-03-01

    The electronic structure of certain crystal lattices can contain multiple degenerate valleys for their charge carriers to occupy. The principal challenge in the development of valleytronics is to lift the valley degeneracy of charge carriers in a controlled way. In bulk semi-metallic bismuth, the Fermi surface includes three cigar-shaped electron valleys lying almost perpendicular to the high symmetry axis known as the trigonal axis. The in-plane mass anisotropy of each valley exceeds 200 as a consequence of Dirac dispersion, which drastically reduces the effective mass along two out of the three orientations. According to our recent study of angle-dependent magnetoresistance in bismuth, a flow of Dirac electrons along the trigonal axis is extremely sensitive to the orientation of in-plane magnetic field. Thus, a rotatable magnetic field can be used as a valley valve to tune the contribution of each valley to the total conductivity. As a consequence of a unique combination of high mobility and extreme mass anisotropy in bismuth, the effect is visible even at room temperature in a magnetic field of 1 T. Thus, a modest magnetic field can be used as a valley valve in bismuth. The results of our recent investigation of angle-dependent magnetoresistance in other semi-metals and doped semiconductors suggest that a rotating magnetic field can behave as a valley valve in a multi-valley system with sizeable mass anisotropy.

  20. Greening Turner Valley

    International Nuclear Information System (INIS)

    Byfield, M.

    2010-01-01

    This article discussed remedial activities undertaken in the Turner Valley. Remedial action in the valley must satisfy the financial concerns of engineers and investors as well as the environmental concerns of residents and regulators. Natural gas production in the Turner Valley began in 1914. The production practices were harmful and wasteful. Soil and water pollution was not considered a problem until recently. The impacts of cumulative effects and other pollution hazards are now being considered as part of many oil and gas environmental management programs. Companies know it is cheaper and safer to prevent pollutants from being released, and more efficient to clean them up quickly. Oil and gas companies are also committed to remediating historical problems. Several factors have simplified remediation plans in the Turner Valley. Area real estate values are now among the highest in Alberta. While the valley residents are generally friendly to the petroleum industry, strong communication with all stakeholders in the region is needed. 1 fig.

  1. Towards a Detailed Seismic Structure of the Valley of Mexico's Xochimilco Lake Zone.

    Science.gov (United States)

    Rabade, S.; Sanchez-Sanchez, J.; Ayala Hernandez, M.; Macias, M. A.; Aguilar Calderon, L. A.; Alcántara, L.; Almora Mata, D.; Castro Parra, G.; Delgado, R.; Leonardo Suárez, M.; Molina Avila, I.; Mora, A.; Perez-Yanez, C.; Ruiz, A. L.; Sandoval, H.; Torres Noguez, M.; Vazquez Larquet, R.; Velasco Miranda, J. M.; Aguirre, J.; Ramirez-Guzmán, L.

    2017-12-01

    Six centuries of gradual, intentional sediment filling in the Xochimilco Lake Zone have drastically reduced the size of the lake. The basin structure and the lake's clay limits and thickness are poorly constrained, and yet, essential to explain the city's anomalous ground motion. Therefore, we conducted an experiment to define the 3D velocity model of Mexico's capital; the CDMX-E3D. The initial phase involved the deployment of a moving set of 18-broadband stations with an interstation distance of 500m over a period of 19 weeks. We collected the data and analyzed the results for the Xochimilco Lake Zone using H/V Spectral Ratios (Nakamura, 1989), which provided an improved fundamental period map of the region. Results show that periods in the former lake zone have larger variability than values previously estimated. In order to obtain group velocity maps at different periods, we estimated Green's functions from ambient noise cross-correlations following standard methodologies to invert Rayleigh wave travel times (Bensen et al., 2007). Preliminary result show very low-velocity zones (100 m/s) and thick sediment layers in most of the former Xochimilco Lake area. This Project was funded by the Secretaria de Ciencia, Tecnología e Innovación (SECITI) of Mexico City. Project SECITI/073/2016.

  2. Radon measurements of groundwater in Mexico

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Cortes, A.

    1991-01-01

    Radon measurement has important applications in hydrogeological studies. Specifically, radon measurement is used to determine the fluctuations of the piezometric levels in groundwater and, in some cases, the path of the water, which is one of the key parameters for evaluating hydrogeological resources. Water from springs and deep wells in the Basin of Mexico and the valley of San Luis Potosi were sampled, measured and analyzed by previous authors. In this work, a method for measuring 222 Rn in groundwater by using a passive detector is presented and the results are compared with a similar experiment performed at the same time, using a dynamic method. The aim of the work is to develop a method for detecting, evaluating and measuring the 222 Rn in groundwater by using SSNTD technology. (author)

  3. Use of satellite data to estimate radiation and evaporation for northwest Mexico

    International Nuclear Information System (INIS)

    Stewart, J.B.; Watts, C.J.; Rodriguez, J.C.; Bruin, H.A.R. de; Berg, A.R. van den; Garatuza-Payán, J.

    1999-01-01

    Incoming solar radiation was estimated from visible band data obtained by the GOES satellite over northwest Mexico. Comparisons against ground-based measurements of incoming solar radiation showed good agreement, particularly in months with low cloud cover. The data from an automatic weather station installed within the Yaqui Valley Irrigation Scheme was used to estimate potential evaporation from a formula based on incoming solar radiation and climatological values of temperature. The success of this formula was assessed by comparison against potential evaporation estimated using the Penman and Penman–Monteith formulae and measurements of net radiation. (author)

  4. Valley-filtered edge states and quantum valley Hall effect in gated bilayer graphene.

    Science.gov (United States)

    Zhang, Xu-Long; Xu, Lei; Zhang, Jun

    2017-05-10

    Electron edge states in gated bilayer graphene in the quantum valley Hall (QVH) effect regime can carry both charge and valley currents. We show that an interlayer potential splits the zero-energy level and opens a bulk gap, yielding counter-propagating edge modes with different valleys. A rich variety of valley current states can be obtained by tuning the applied boundary potential and lead to the QVH effect, as well as to the unbalanced QVH effect. A method to individually manipulate the edge states by the boundary potentials is proposed.

  5. Spring migration of Northern Pintails from Texas and New Mexico, USA

    Science.gov (United States)

    Haukos, D.A.; Miller, M.R.; Orthmeyer, D.L.; Takekawa, John Y.; Fleskes, J.P.; Casazza, Michael L.; Perry, W.M.; Moon, J.A.

    2006-01-01

    We used satellite transmitters (platform transmitting terminals or PTTs) during 2002 and 2003 to document spring migration timing, routes, stopover sites, and nesting sites of adult female Northern Pintails (Anas acuta) from major wintering areas of the Gulf Coast (N = 20) and Playa Lakes Regions (PLR, N = 20) in Texas, and the Middle Rio Grande Valley, New Mexico (MRGV, N = 15). Some Pintails tagged in the MRGV continued movements into Mexico. Poor winter survival or PTT failure reduced sample size to 15 for PLR Pintails, 5 for Gulf Coast Pintails, and 11 for MRGV Pintails. Apparent winter survival was 66% lower for Texas Gulf Coast PTT-tagged Pintails than for those from the PLR and MRGV. Pintails from each area used different routes to their respective breeding grounds. PTT-tagged Pintails from the MRGV followed the Rio Grande Valley north to southern Colorado, before traveling on to the Dakotas and Canada or traveled northeast and joined the migration of PLR Pintails in Texas or Kansas. The latter made initial stops in Kansas, Nebraska, Colorado, or the Dakotas. Gulf Coast Pintails traveled through north-central Oklahoma or central Kansas. Pintails that had stopped first in Kansas or Nebraska tended to settle to nest in the United States. Wetland availability in the Prairie Pothole Region of the Northern Great Plains influenced nesting destinations of PTT-tagged Pintails, but individuals settled across a wide swath of northern North America. We did not detect any consistently-used spring staging areas. Therefore, negative impacts to any of the marked populations, or their wetland habitats, may have continental implications.

  6. 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,…

  7. Volcanic settings and their reservoir potential: An outcrop analog study on the Miocene Tepoztlán Formation, Central Mexico

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2011-07-01

    The reservoir potential of volcanic and associated sedimentary rocks is less documented in regard to groundwater resources, and oil and gas storage compared to siliciclastic and carbonate systems. Outcrop analog studies within a volcanic setting enable to identify spatio-temporal architectural elements and geometric features of different rock units and their petrophysical properties such as porosity and permeability, which are important information for reservoir characterization. Despite the wide distribution of volcanic rocks in Mexico, their reservoir potential has been little studied in the past. In the Valley of Mexico, situated 4000 m above the Neogene volcanic rocks, groundwater is a matter of major importance as more than 20 million people and 42% of the industrial capacity of the Mexican nation depend on it for most of their water supply. Here, we present porosity and permeability data of 108 rock samples representing five different lithofacies types of the Miocene Tepoztlán Formation. This 800 m thick formation mainly consists of pyroclastic rocks, mass flow and fluvial deposits and is part of the southern Transmexican Volcanic Belt, cropping out south of the Valley of Mexico and within the two states of Morelos and Mexico State. Porosities range from 1.4% to 56.7%; average porosity is 24.8%. Generally, permeabilities are low to median (0.2-933.3 mD) with an average permeability of 88.5 mD. The lavas are characterized by the highest porosity values followed by tuffs, conglomerates, sandstones and tuffaceous breccias. On the contrary, the highest permeabilities can be found in the conglomerates, followed by tuffs, tuffaceous breccias, sandstones and lavas. The knowledge of these petrophysical rock properties provides important information on the reservoir potential of volcanic settings to be integrated to 3D subsurface models.

  8. Continental rupture and the creation of new crust in the Salton Trough rift, Southern California and northern Mexico: Results from the Salton Seismic Imaging Project

    Science.gov (United States)

    Han, Liang; Hole, John A.; Stock, Joann M.; Fuis, Gary S.; Kell, Annie; Driscoll, Neal W.; Kent, Graham M.; Harding, Alistair J.; Rymer, Michael J.; González-Fernández, Antonio; Lázaro-Mancilla, Octavio

    2016-10-01

    A refraction and wide-angle reflection seismic profile along the axis of the Salton Trough, California and Mexico, was analyzed to constrain crustal and upper mantle seismic velocity structure during active continental rifting. From the northern Salton Sea to the southern Imperial Valley, the crust is 17-18 km thick and approximately one-dimensional. The transition at depth from Colorado River sediment to underlying crystalline rock is gradual and is not a depositional surface. The crystalline rock from 3 to 8 km depth is interpreted as sediment metamorphosed by high heat flow. Deeper felsic crystalline rock could be stretched preexisting crust or higher-grade metamorphosed sediment. The lower crust below 12 km depth is interpreted to be gabbro emplaced by rift-related magmatic intrusion by underplating. Low upper mantle velocity indicates high temperature and partial melting. Under the Coachella Valley, sediment thins to the north and the underlying crystalline rock is interpreted as granitic basement. Mafic rock does not exist at 12-18 km depth as it does to the south, and a weak reflection suggests Moho at 28 km depth. Structure in adjacent Mexico has slower midcrustal velocity, and rocks with mantle velocity must be much deeper than in the Imperial Valley. Slower velocity and thicker crust in the Coachella and Mexicali valleys define the rift zone between them to be >100 km wide in the direction of plate motion. North American lithosphere in the central Salton Trough has been rifted apart and is being replaced by new crust created by magmatism, sedimentation, and metamorphism.

  9. Continental rupture and the creation of new crust in the Salton Trough rift, southern California and northern Mexico: Results from the Salton Seismic Imaging Project

    Science.gov (United States)

    Han, Liang; Hole, John A.; Stock, Joann M.; Fuis, Gary S.; Kell, Annie; Driscoll, Neal W.; Kent, Graham M.; Rymer, Michael J.; Gonzalez-Fernandez, Antonio; Aburto-Oropeza, Octavio

    2016-01-01

    A refraction and wide-angle reflection seismic profile along the axis of the Salton Trough, California and Mexico, was analyzed to constrain crustal and upper mantle seismic velocity structure during active continental rifting. From the northern Salton Sea to the southern Imperial Valley, the crust is 17-18 km thick and approximately one-dimensional. The transition at depth from Colorado River sediment to underlying crystalline rock is gradual and is not a depositional surface. The crystalline rock from ~3 to ~8 km depth is interpreted as sediment metamorphosed by high heat flow. Deeper felsic crystalline rock could be stretched pre-existing crust or higher grade metamorphosed sediment. The lower crust below ~12 km depth is interpreted to be gabbro emplaced by rift-related magmatic intrusion by underplating. Low upper-mantle velocity indicates high temperature and partial melting. Under the Coachella Valley, sediment thins to the north and the underlying crystalline rock is interpreted as granitic basement. Mafic rock does not exist at 12-18 depth as it does to the south, and a weak reflection suggests Moho at ~28 km depth. Structure in adjacent Mexico has slower mid-crustal velocity and rocks with mantle velocity must be much deeper than in the Imperial Valley. Slower velocity and thicker crust in the Coachella and Mexicali valleys define the rift zone between them to be >100 km wide in the direction of plate motion. North American lithosphere in the central Salton Trough has been rifted apart and is being replaced by new crust created by magmatism, sedimentation, and metamorphism.

  10. Education Outreach Associated with Technology Transfer in a Colonia of South Texas: Green Valley Farms Science and Space Club for Middle School Aged Children in Green Valley Farms, San Benito, Texas

    Science.gov (United States)

    Potess, Marla D.; Rainwater, Ken; Muirhead, Dean

    2004-01-01

    Texas colonias are unincorporated subdivisions characterized by inadequate water and wastewater infrastructure, inadequate drainage and road infrastructure, substandard housing, and poverty. Since 1989 the Texas Legislature has implemented policies to halt further development of colonias and to address water and wastewater infrastructure needs in existing and new colonias along the border with Mexico. Government programs and non-government and private organization projects aim to address these infrastructure needs. Texas Tech University's Water Resources Center demonstrated the use of alternative on-site wastewater treatment in the Green Valley Farms colonia, San Benito, Texas. The work in Green Valley Farms was a component of a NASA-funded project entitled Evaluation of NASA's Advanced Life Support Integrated Water Recovery System for Non-Optimal Conditions and Terrestrial Applications. Two households within the colonia are demonstration sites for constructed wetlands. A colonia resident and activist identified educational opportunities for colonia children as a primary goal for many colonia residents. Colonia parents view education as the door to opportunity and escape from poverty for their children. The educational outreach component of the project in Green Valley Farms was a Science and Space Club for middle-school age students. Involved parents, schoolteachers, and school administrators enthusiastically supported the monthly club meetings and activities. Each month, students participated in interactive learning experiences about water use and reuse in space and on earth. Activities increased knowledge and interest in water resource issues and in science and engineering fields. The Institute for the Development and Enrichment of Advanced Learners (IDEAL) at Texas Tech University provided full scholarships for five students from Green Valley Farms to attend the Shake Hands With Your Future camp at Texas Tech University in June 2003. The educational outreach

  11. Valley development on Hawaiian volcanoes

    International Nuclear Information System (INIS)

    Baker, V.R.; Gulick, V.C.

    1987-01-01

    Work in progress on Hawaiian drainage evolution indicates an important potential for understanding drainage development on Mars. Similar to Mars, the Hawaiian valleys were initiated by surface runoff, subsequently enlarged by groundwater sapping, and eventually stabilized as aquifers were depleted. Quantitative geomorphic measurements were used to evaluate the following factors in Hawaiian drainage evolution: climate, stream processes, and time. In comparing regions of similar climate, drainage density shows a general increase with the age of the volcani island. With age and climate held constant, sapping dominated valleys, in contrast to runoff-dominated valleys, display the following: lower drainage densities, higher ratios of valley floor width to valley height, and more positive profile concavities. Studies of stream junction angles indicate increasing junction angles with time on the drier leeward sides of the major islands. The quantitative geomorphic studies and earlier field work yielded important insights for Martian geomorphology. The importance of ash mantling in controlling infiltration on Hawaii also seems to apply to Mars. The Hawaiian valley also have implications for the valley networks of Martian heavily cratered terrains

  12. Geochemistry of Mariano lake-lake valley cores, McKinley County, New Mexico

    International Nuclear Information System (INIS)

    Leventhal, J.S.; Lichte, F.E.; Gent, C.A.

    1990-01-01

    The primary goal of the U.S. Geological Survey-Bureau of Indian Affairs drilling project in the Upper Jurassic Morrison Formation in McKinley County, New Mexico, was to better understand the relationship between host-rock stratigraphy and uranium mineralization. As part of this project, geochemical studies of approximately 280 samples from 8 cores and 1 outcrop were undertaken; samples from 4 cores show uranium enrichment. Geochemical relationships between samples of weathered outcrop, oxidized core, reduced (unmineralized) core, and ore-bearing core were contrasted by comparison of element abundances. Special comparative studies of sandstone and clay chemistry were made using results from x-ray diffraction, optical petrography, and chemical analysis. Results of these studies are discussed

  13. Municipal solid waste characterizations and management strategies for the Lower Rio Grande Valley, Texas.

    Science.gov (United States)

    Chang, Ni-Bin; Davila, Eric

    2008-01-01

    The Lower Rio Grande Valley (LRGV or Valley) in Texas, facing the big waste management challenge along the US-Mexico border today, is at the crossroads as a result of the rapid population growth, the scarcity of landfill space, the bi-nation's trade impacts, and the illusive goal of environmental sustainability. This paper offers a unique municipal solid waste investigation with regard to both physical and chemical characteristics leading to illuminate the necessary management policies with greater regional relevancy. With multiple sampling campaigns conducted during the spring of 2005, this study holistically summarizes the composition of solid waste, the statistical distribution patterns of key recyclable items, and the heating value in an uncertain environment. Research findings indicate that high fractions of plastics and paper in the waste stream imply a strong potential for energy recovery. Incineration options are thus bolstered by mildly high heating values across 10 cities in this region, which may lead to save land resources required for final disposal and increase electricity generation in the long run. Additional regression analyses further identify the correlation between recyclable items and heating value, which show that current recycling programs permit no obvious negative impacts on the incineration option. Final statistical hypothesis tests for both the Brownsville-Harlingen-San Benito and the McAllen-Edinburg-Mission metropolitan regions help foster consistent management strategies across the Valley regardless of the trivial differences of waste characteristics in between.

  14. Analysis of Mining-induced Valley Closure Movements

    Science.gov (United States)

    Zhang, C.; Mitra, R.; Oh, J.; Hebblewhite, B.

    2016-05-01

    Valley closure movements have been observed for decades in Australia and overseas when underground mining occurred beneath or in close proximity to valleys and other forms of irregular topographies. Valley closure is defined as the inward movements of the valley sides towards the valley centreline. Due to the complexity of the local geology and the interplay between several geological, topographical and mining factors, the underlying mechanisms that actually cause this behaviour are not completely understood. A comprehensive programme of numerical modelling investigations has been carried out to further evaluate and quantify the influence of a number of these mining and geological factors and their inter-relationships. The factors investigated in this paper include longwall positional factors, horizontal stress, panel width, depth of cover and geological structures around the valley. It is found that mining in a series passing beneath the valley dramatically increases valley closure, and mining parallel to valley induces much more closure than other mining orientations. The redistribution of horizontal stress and influence of mining activity have also been recognised as important factors promoting valley closure, and the effect of geological structure around the valley is found to be relatively small. This paper provides further insight into both the valley closure mechanisms and how these mechanisms should be considered in valley closure prediction models.

  15. Symptoms of insomnia among adolescents in the lower Rio Grande Valley of Texas.

    Science.gov (United States)

    Roberts, Robert E; Lee, Eun Sul; Hemandez, Mike; Solari, Ana Cristina

    2004-06-15

    To estimate the prevalence of symptoms of insomnia among adolescents living along the United States-Mexico border and to examine whether ethnicity and birthplace affect risk for such symptoms. Cross-sectional school-based survey using a version of the 2001 Youth Risk Behavior Survey, modified to elicit data on sleep problems. A probability sample of 13 high schools selected from more than 40 high schools in the 4 southernmost counties in Texas-the Lower Rio Grande Valley-contiguous with Mexico. All ninth-grade students who agreed to participate (n = 5,118). The sleep module consisted of queries about trouble initiating asleep, trouble maintaining sleep, early morning waking, nonrestorative sleep, quality of sleep, and amount of sleep. Symptoms of insomnia were common, with 12.4% of respondents meeting symptom criteria for insomnia almost every day of the past month. Females were more likely to report insomnia, as were youths reporting lower socioeconomic status. Crude odds ratios suggested foreign-born and those who identified themselves as "Mexican" rather than "Mexican American" were at lower risk of insomnia. However, multivariate analyses eliminated these differences. More comparative research is needed to ascertain whether and how ethnic culture affects risk for disordered sleep.

  16. Detection of Fracture Patterns Within the Southern Portion of a Residential Complex (Tepozanes), Los Reyes-La Paz County (Edo. de Mexico)

    Science.gov (United States)

    Chavez, R. E.; Arango, C.; Tejero, A.; Cifuentes, G.; Hernandez, E.

    2008-12-01

    Most of the urban zone within the Valley of Mexico is built on top of the sediments of the ancient lakes of Chalco, Xochimilco, Mexico, Texcoco, Xaltocan and Zumpango. The sediments that cover this great valley are mainly composed by highly saturated clay-sandy materials; which offer a weak resistance to the constructions built on top. In addition, the increasing need of water supply for the population living in the valley (~22 million inhabitants) has weakened the main groundwater aquifers. This has lead to a differentiated subsidence and collapse of buildings, habitation units and roads. These effects put in a serious risk the inhabitants and the infrastructure of the city. As an example, we present a case of an area located in a densely populated zone, within a low-income residential complex denominated Tepozanes. This is located in the Los Reyes-La Paz County (Mexico State), towards the southeastern portion of the Valley of Mexico. The area is geologically limited by the Chimalhuacan Hill to the N, by the Santa Catarina volcanic range to the S. The previously mentioned effects are evident in the constructions of some buildings, where an exposed fracture is found in the NE-SW direction. This feature is affecting the structure of one of them in the residential complex, where the fracture runs underneath. A geophysical study was proposed to characterize the subsoil and to define the fracturing patterns in the zone. The electrical resistivity tomography (ETR) method employing the capacitive and galvanic modes was used to define the fracturing patters and the position at depth of the saturated layers, which might affect the Residential buildings. As a complement, GPR (Ground Penetrating Radar) profiles were carried out on the same profiles to correlate the information obtained from the ETR capacitive method which has a better resolution in the shallower zone. The computed results show that the buildings foundations were set on top of a high resistivity layer (~1000

  17. Twelve years of continuous measurements of atmospheric electrical activity in Mexico's Tropical highland

    Energy Technology Data Exchange (ETDEWEB)

    Troncoso Lozada, O. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D.F. (Mexico)

    2004-04-01

    Atmospheric electric activity measurements have been recorded continuously by a punctual lightning system at a tropical highland observatory from 1988 onwards, and were analyzed to obtain lightning statistical confident results for thunderstorms occurrence on the leeward side of the southern mountain ridge of Mexico's Valley. Shown, as examples, are individual profiles of the atmospheric electrical activity, associated with severe storms. The results make clear that the fastest possible sequence of electrical measurements is required to obtain significant and applications oriented data in connection with a whole series of thunderstorms taking into account the mean time variation of the atmospheric electricity measurements at an altitude of 2270 m a.s.l. The seasonal variation indicates that the lightning flash peak currents were found to be larger in summer with less than 10% occurring in the autumn and winter. With rainfall data from a network of 66 stations, we obtained a significant correlation with the lightning frequency. Special attention was undertaken concerning the question of the atmospheric electrical activity and climate at Valley of Mexico. [Spanish] Se midieron ininterrumpidamente las variaciones de la actividad electrica en la atmosfera, de enero de 1988 a diciembre de 1999, en un observatorio de altura (2,250 m s.n.m.), y se analizaron para obtener resultados estadisticos confiables con relacion a la ocurrencia de tormentas en la region sur del Valle de Mexico. Como ejemplos, se muestran los perfiles individuales de la actividad electrica atmosferica asociada con tormentas severas. Los resultados dejan claro que se requiere de la secuencia de medidas electricas lo mas rapida posible para obtener datos significativos y aplicables en relacion con una serie completa de tormentas, considerando la media del tiempo de variacion de las mediciones de la actividad electrica atmosferica a una altitud de 2,270 m s.n.m. La validacion estacional indica que

  18. The seduction of models. Chinampa agriculture in Mexico.

    Science.gov (United States)

    Chapin, M

    1988-01-01

    Considerable excitement accompanied Mexico's plan in the mid-1970s to build "Chinampas," in the swampy region of Veracruz and Tabasco, that is, agriculture involving the construction of raised farming beds in shallow lakes or marshes. The plan was devised by Mexico's Instituto Nacional de Investigaciones sobre los Recursos Bioticos (INIREB). Perfected by the inhabitants of the Valley of Mexico before the Spanish Conquest, chinampas had nearly vanished except in a few isolated and shrinking areas around Mexico City. The chinampas have been steadily constricted in recent years as Mexico City has extended out and swallowed the best known of them, Xochimilco. The introduction of chinampa technology in Tucta, a Chontal village of approximately 300 families in 1978, began on a grand scale. The INI's objectives for the project were: to provide the landless Chontale Indians with permanent employment; to bring about self-sufficient food production in the area; to ensure a constant production of vegetables for the internal market of Villahermosa; to strengthen indigenous cultural identity; and to develop a real alternative for the incorporation of swampland into productive activities. In 1979, INIREB became involved in a 2nd chinampa project in the "ejido" of El Castillo, Veracruz. El Castillo was selected as an experimental project site because of the lake as well as the village's proximity to INIREB's central office in Xalapa, rather than community interest in chinampas. The examples of chinampa technology transfer presented had different outcomes, but they shared several crucial defects. In both cases, the stated and unstated objectives of project managers had little fit with the interests and needs of the farmers. The 2 projects were designed and implemented by outside technicians without significant local participation, and both rapidly fell apart when "beneficiaries" failed to cooperate. The Chontal case is notable because, after a series of failures, it finally worked

  19. Evolution under domestication: ongoing artificial selection and divergence of wild and managed Stenocereus pruinosus (Cactaceae) populations in the Tehuacan Valley, Mexico.

    Science.gov (United States)

    Parra, Fabiola; Casas, Alejandro; Peñaloza-Ramírez, Juan Manuel; Cortés-Palomec, Aurea C; Rocha-Ramírez, Víctor; González-Rodríguez, Antonio

    2010-09-01

    The Tehuacán Valley in Mexico is a principal area of plant domestication in Mesoamerica. There, artificial selection is currently practised on nearly 120 native plant species with coexisting wild, silvicultural and cultivated populations, providing an excellent setting for studying ongoing mechanisms of evolution under domestication. One of these species is the columnar cactus Stenocereus pruinosus, in which we studied how artificial selection is operating through traditional management and whether it has determined morphological and genetic divergence between wild and managed populations. Semi-structured interviews were conducted with 83 households of three villages to investigate motives and mechanisms of artificial selection. Management effects were studied by comparing variation patterns of 14 morphological characters and population genetics (four microsatellite loci) of 264 plants from nine wild, silvicultural and cultivated populations. Variation in fruit characters was recognized by most people, and was the principal target of artificial selection directed to favour larger and sweeter fruits with thinner or thicker peel, fewer spines and pulp colours other than red. Artificial selection operates in agroforestry systems favouring abundance (through not felling plants and planting branches) of the preferred phenotypes, and acts more intensely in household gardens. Significant morphological divergence between wild and managed populations was observed in fruit characters and plant vigour. On average, genetic diversity in silvicultural populations (H(E) = 0.743) was higher than in wild (H(E) = 0.726) and cultivated (H(E) = 0.700) populations. Most of the genetic variation (90.58 %) occurred within populations. High gene flow (Nm(FST) > 2) was identified among almost all populations studied, but was slightly limited by mountains among wild populations, and by artificial selection among wild and managed populations. Traditional management of S. pruinosus involves

  20. A landscape scale valley confinement algorithm: Delineating unconfined valley bottoms for geomorphic, aquatic, and riparian applications

    Science.gov (United States)

    David E. Nagel; John M. Buffington; Sharon L. Parkes; Seth Wenger; Jaime R. Goode

    2014-01-01

    Valley confinement is an important landscape characteristic linked to aquatic habitat, riparian diversity, and geomorphic processes. This report describes a GIS program called the Valley Confinement Algorithm (VCA), which identifies unconfined valleys in montane landscapes. The algorithm uses nationally available digital elevation models (DEMs) at 10-30 m resolution to...

  1. Spatial Analysis of the Level of Exposure to Seismic Hazards of Health Facilities in Mexico City, Mexico

    Science.gov (United States)

    Moran, S.; Novelo-Casanova, D. A.

    2011-12-01

    Although health facilities are essential infrastructure during disasters and emergencies, they are also usually highly vulnerable installations in the case of the occurrence of large and major earthquakes. Hospitals are one of the most complex critical facilities in modern cities and they are used as first response in emergency situations. The operability of a hospital must be maintained after the occurrence of a local strong earthquake in order to satisfy the need for medical care of the affected population. If a health facility is seriously damaged, it cannot fulfill its function when most is needed. In this case, hospitals become a casualty of the disaster. To identify the level of physical exposure of hospitals to seismic hazards in Mexico City, we analyzed their geographic location with respect to the seismic response of the different type of soils of the city from past earthquakes, mainly from the events that occurred on September 1985 (Ms= 8.0) and April 1989 (Ms= 6.9). Seismic wave amplification in this city is the result of the interaction of the incoming seismic waves with the soft and water saturated clay soils, on which a large part of Mexico City is built. The clay soils are remnants of the lake that existed in the Valley of Mexico and which has been drained gradually to accommodate the growing urban sprawl. Hospital facilities were converted from a simple database of names and locations into a map layer of resources. This resource layer was combined with other map layers showing areas of seismic microzonation in Mexico City. This overlay was then used to identify those hospitals that may be threatened by the occurrence of a large or major seismic event. We analyzed the public and private hospitals considered as main health facilities. Our results indicate that more than 50% of the hospitals are highly exposed to seismic hazards. Besides, in most of these health facilities we identified the lack of preventive measures and preparedness to reduce their

  2. Small martian valleys: Pristine and degraded morphology

    International Nuclear Information System (INIS)

    Baker, V.R.; Partridge, J.B.

    1986-01-01

    The equatorial heavily cratered uplands of Mars are dissected by two classes of small valleys that are intimately associated in compound networks. Pristine valleys with steep valley walls preferentially occupy downstream portions of compound basins. Degraded valleys with eroded walls are laterally more extensive and have higher drainage densities than pristine valleys. Morphometric and crater-counting studies indicate that relatively dense drainage networks were emplaced on Mars during the heavy bombardment about 4.0 b.y. ago. Over a period of approximately 10 8 years, these networks were degraded and subsequently invaded by headwardly extending pristine valleys. The pristine valleys locally reactivated the compound networks, probably through sapping processes dependent upon high water tables. Fluvial activity in the heavily cratered uplands generally ceased approximately 3.8--3.9 b.y. ago, coincident with the rapid decline in cratering rates. The relict compound valleys on Mars are morphometrically distinct from most terrestrial drainage systems. The differences might be caused by a Martian valley formation episode characterized by hyperaridity, by inadequate time for network growth, by very permeable rock types, or by a combination of factors

  3. Characterization of atmospheric bioaerosols at 9 sites in Tijuana, Mexico

    Science.gov (United States)

    Hurtado, Lilia; Rodríguez, Guillermo; López, Jonathan; Castillo, J. E.; Molina, Luisa; Zavala, Miguel; Quintana, Penelope J. E.

    2014-10-01

    The atmosphere is not considered a habitat for microorganisms, but can exist in the atmosphere as bioaerosols. These microorganisms in the atmosphere have great environmental importance through their influence on physical processes such as ice nucleation and cloud droplet formation. Pathogenic airborne microorganisms may also have public health consequences. In this paper we analyze the microbial concentration in the air at three sites in Tijuana, Mexico border during the Cal-Mex 2010 air quality campaign and from nine sites over the following year. Samples were collected by impaction with the air analyzer Millipore M Air T, followed by incubation and counting as colony forming units (CFU) of viable colonies. Airborne microbial contamination average levels ranged from a low of 230 ± 130 CFU/m³ in the coastal reference site to an average of 40,100 ± 21,689 CFU/m³ in the Tijuana river valley. We found the highest microbial load in the summer and the lowest values in the winter. Potentially pathogenic bacteria were isolated from the samples, with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis being most common. This work is the first evaluation of bioaerosols in Tijuana, Mexico.

  4. Geologic summary of the Owens Valley drilling project, Owens and Rose Valleys, Inyo County, California

    International Nuclear Information System (INIS)

    Schaer, D.W.

    1981-07-01

    The Owens Valley Drilling Project consists of eight drill holes located in southwest Inyo County, California, having an aggregate depth of 19,205 feet (5853 m). Project holes penetrated the Coso Formation of upper Pliocene or early Pleistocene age and the Owens Lake sand and lakebed units of the same age. The project objective was to improve the reliability of uranium-potential-resource estimates assigned to the Coso Formation in the Owens Valley region. Uranium-potential-resource estimates for this area in $100 per pound U 3 O 8 forward-cost-category material have been estimatd to be 16,954 tons (15,384 metric tons). This estimate is based partly on project drilling results. Within the Owens Valley project area, the Coso Formation was encountered only in the Rose Valley region, and for this reason Rose Valley is considered to be the only portion of the project area favorable for economically sized uranium deposits. The sequence of sediments contained in the Owens Valley basin is considered to be largely equivalent but lithologically dissimilar to the Coso Formation of Haiwee Ridge and Rose Valley. The most important factor in the concentration of significant amounts of uranium in the rock units investigated appears to be the availability of reducing agents. Significant amounts of reductants (pyrite) were found in the Coso Formation. No organic debris was noted. Many small, disconnected uranium occurrences, 100 to 500 ppM U 3 O 8 , were encountered in several of the holes

  5. Environmental effects of aquifer overexploitation: a case study in the highlands of Mexico.

    Science.gov (United States)

    Esteller, Maria Vicenta; Diaz-Delgado, Carlos

    2002-02-01

    There are several environmental processes occurring under aquifer overexploitation conditions. These processes include groundwater table decline, subsidence, attenuation and drying of springs, decrease of river flow, and increased pollution vulnerability, among others processes. Some of these effects have been observed on the Upper Basin of the Lerma River. The Lerma River begins in the SE of the Valley of Toluca at 2,600 m asl, in the wetland known as Lagoons of Almoloya del Río. This wetland is made up of a group of lagoons, which are an important aquatic system from an environmental point of view. The water inflow of this wetland is a discharge of springs, which occur between the fractured volcanic material of the mountain range and granular volcanic-continental deposits of the Valley of Toluca aquifer. The intensive exploitation of the Valley of Toluca aquifer to supply urban and industrial water to Mexico City and Toluca began in 1950 and is responsible for a steady decline of piezometric levels of 1-3.5 m/yr. Other effects of this exploitation--the drying of the wetland, the decrease of river flow and the land subsidence--caused serious ecological and social impacts. The authorities declared this aquifer as overexploited in order to reduce the exploitation and preserve the availability of water resources in this important region.

  6. Financing options in Mexico`s energy industry

    Energy Technology Data Exchange (ETDEWEB)

    McKenna, J.J. [PricewaterhouseCoopers Securities, Houston, TX (United States)

    1999-10-01

    A series of brief notes accompanied this presentation which was divided into seven sections entitled: (1) capital markets update, (2) Mexican financial market update, (3) financing options in the energy industry, (4) the Venezuelan experience at La Apertura, (5) private and strategic equity alternatives, (6) Pricewaterhouse Coopers Securities, and (7) Mexico energy 2005 prediction. The paper focused on how the financial crisis and merger activity in Latin America will impact electricity reform in Mexico. It was noted that under Mexico`s Policy Proposal for Electricity Reform of the Mexican Electricity Industry, the financial community will seek to back companies in power generation, transportation and distribution. The difficulty of financing government businesses undergoing privatization was also discussed with particular emphasis on the challenge of accepting political and regulatory risks. The Latin private equity market and Canadian investment in Mexico was also reviewed. Since NAFTA (North American Free Trade Agreement) went into affect in 1994, Canadian investment in Mexico has more than tripled. Canadian companies have invested more than C$1.7 billion in Mexico since NAFTA. Pricewaterhouse Coopers Securities is a global investment bank which sees large opportunities in the Mexican energy market. They predict that in five years, Mexico will experience a gradual liberalization of the oil and gas sector, and a full liberalization of the gas pipeline and distribution business and the power generation, transmission and distribution business. 3 figs.

  7. Valley dependent transport in graphene L junction

    Science.gov (United States)

    Chan, K. S.

    2018-05-01

    We studied the valley dependent transport in graphene L junctions connecting an armchair lead and a zigzag lead. The junction can be used in valleytronic devices and circuits. Electrons injected from the armchair lead into the junction is not valley polarized, but they can become valley polarized in the zigzag lead. There are Fermi energies, where the current in the zigzag lead is highly valley polarized and the junction is an efficient generator of valley polarized current. The features of the valley polarized current depend sensitively on the widths of the two leads, as well as the number of dimers in the armchair lead, because this number has a sensitive effect on the band structure of the armchair lead. When an external potential is applied to the junction, the energy range with high valley polarization is enlarged enhancing its function as a generator of highly valley polarized current. The scaling behavior found in other graphene devices is also found in L junctions, which means that the results presented here can be extended to junctions with larger dimensions after appropriate scaling of the energy.

  8. Mexico Geoid Heights (MEXICO97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' geoid height grid for Mexico, and North-Central America, is the MEXICO97 geoid model. The computation used about one million terrestrial and marine gravity...

  9. Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California

    Science.gov (United States)

    Schubert, Brian A.; Lowenstein, Tim K.; Timofeeff, Michael N.

    2009-06-01

    Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 μm diameter cocci, <2.5 μm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System.

  10. Unpacking the social construction of 'natural' disaster through policy discourses and institutional responses in Mexico: the case of Chalco Valley's floods, State of Mexico

    OpenAIRE

    Aragón-Durand, F. d. J.

    2009-01-01

    This research analyses 'natural' disaster policies for Mexico. The objective is to demonstrate that 'natural' disaster and the policies oriented to prevent them are socially constructed. It adopts a constructionist perspective because it is concerned with the understanding of collective social constructions of meaning and knowledge that are determined by political and social processes. This study focuses on the relation between the discourses of disaster causality, policy problem construction...

  11. Topological Valley Transport in Two-dimensional Honeycomb Photonic Crystals.

    Science.gov (United States)

    Yang, Yuting; Jiang, Hua; Hang, Zhi Hong

    2018-01-25

    Two-dimensional photonic crystals, in analogy to AB/BA stacking bilayer graphene in electronic system, are studied. Inequivalent valleys in the momentum space for photons can be manipulated by simply engineering diameters of cylinders in a honeycomb lattice. The inequivalent valleys in photonic crystal are selectively excited by a designed optical chiral source and bulk valley polarizations are visualized. Unidirectional valley interface states are proved to exist on a domain wall connecting two photonic crystals with different valley Chern numbers. With the similar optical vortex index, interface states can couple with bulk valley polarizations and thus valley filter and valley coupler can be designed. Our simple dielectric PC scheme can help to exploit the valley degree of freedom for future optical devices.

  12. Mechanical control over valley magnetotransport in strained graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

    2016-05-06

    Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

  13. Effect of rate, timing and placement of nitrogen on spring wheat in farmers' fields in the Yaqui Valley of Mexico

    International Nuclear Information System (INIS)

    Ortiz-Monasterio, I.; Naylor, R.

    2000-01-01

    The objective was to validate, in farmers' fields in the Yaqui Valley, N-management practices that had resulted, under experimental conditions, in reduction of trace-gas emissions while maintaining grain yield and quality. Trials were variously established in five different farmers' fields. The local management practice was compared with a new alternative, under various rates of N. The farmers managed all aspects of the trials, except for fertilizer application. The new N-management practice resulted in higher yield, protein and fertilizer recovery. The SPAD chlorophyll meter was found to be a promising tool for predicting grain-protein concentration. The method of application, broadcast vs. banding, did not affect fertilizer-N recovery. We conclude that it is possible to improve N-uptake efficiency in wheat grown in the Valley by delaying most of the N application close to the time of the first auxiliary irrigation. (author)

  14. A Hazy Day in Mexico City

    Science.gov (United States)

    2002-01-01

    . The ancient lakebed valley in which Mexico City is situated became a major source of dust when it was drained in the 16th century. The city basin stretches approximately 70 kilometers wide; it is reported that the local air quality causes the surrounding mountains to be rarely visible from the urban center.The Multi-angle Imaging SpectroRadiometer views almost the entire Earth every 9 days. These images were acquired during Terra orbits 6966 and 10461 and cover an area of 330 kilometers x 464 kilometers. They utilize data from blocks 75 to 77 within World Reference System-2 path 26.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  15. The geochemistry of groundwater resources in the Jordan Valley: The impact of the Rift Valley brines

    Science.gov (United States)

    Farber, E.; Vengosh, A.; Gavrieli, I.; Marie, Amarisa; Bullen, T.D.; Mayer, B.; Polak, A.; Shavit, U.

    2007-01-01

    The chemical composition of groundwater in the Jordan Valley, along the section between the Sea of Galilee and the Dead Sea, is investigated in order to evaluate the origin of the groundwater resources and, in particular, to elucidate the role of deep brines on the chemical composition of the regional groundwater resources in the Jordan Valley. Samples were collected from shallow groundwater in research boreholes on two sites in the northern and southern parts of the Jordan Valley, adjacent to the Jordan River. Data is also compiled from previous published studies. Geochemical data (e.g., Br/Cl, Na/Cl and SO4/Cl ratios) and B, O, Sr and S isotopic compositions are used to define groundwater groups, to map their distribution in the Jordan valley, and to evaluate their origin. The combined geochemical tools enabled the delineation of three major sources of solutes that differentially affect the quality of groundwater in the Jordan Valley: (1) flow and mixing with hypersaline brines with high Br/Cl (>2 ?? 10-3) and low Na/Cl (shallow saline groundwaters influenced by brine mixing exhibit a north-south variation in their Br/Cl and Na/Cl ratios. This chemical trend was observed also in hypersaline brines in the Jordan valley, which suggests a local mixing process between the water bodies. ?? 2007 Elsevier Ltd. All rights reserved.

  16. Texas-Mexico multimodal transportation: developments in Mexico

    Science.gov (United States)

    Boske, Leigh B.

    1994-03-01

    This presentation highlights the results of a recently completed study that examines the Texas- Mexico multimodal transport system already in place, current plans for improvements or expansion, and opportunities and constraints faced by each transport mode -- motor carriage, rail, maritime, and air. Particular emphasis is given to findings regarding transportation developments in Mexico. The study concludes that in Mexico, all modes are working at establishing new services and strategic alliances, intermodal arrangements are on the rise, and private-sector participation in infrastructure improvements is growing daily at Mexican seaports and airports as well as within that nation's highway and rail systems. This presentation looks at developments that concern privatization, deregulation, infrastructure improvements, financing arrangements, and new services in Mexico.

  17. Crustal structure of norther Oaxaca terrane; The Oaxaca and caltepec faults, and the Tehuacan Valley. A gravity study.

    Science.gov (United States)

    Campos-Enriquez, J. O.; Alatorre-Zamora, M. A.; Ramón, V. M.; Belmonte, S.

    2014-12-01

    Northern Oaxaca terrane, southern Mexico, is bound by the Caltepec and Oaxaca faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacan depression. Several gravity profiles across these faults and the Oaxaca terrane (including the Tehuacan Valley) enables us to establish the upper crustal structure of this region. Accordingly, the Oaxaca terrane is downward displaced to the east in two steps. First the Santa Lucia Fault puts into contact the granulitic basamental rocks with Phanerozoic volcanic and sedimentary rocks. Finally, the Gavilan Fault puts into contact the Oaxaca terrane basement (Oaxaca Complex) into contact with the volcano-sedimentary infill of the valley. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex?). A structural high at the western Tehuacan depression accomadates the east dipping faults (Santa Lucia and Gavilan faults) and the west dipping faults of the Oaxaca Fault System. To the west of this high structural we have the depper depocenters. The Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. The faults are regional tectonic structures. They seem to continue northwards below the Trans-Mexican Volcanic Belt. A major E-W to NE-SW discontinuity on the Oaxaca terrane is inferred to exist between profiles 1 and 2. The Tehuacan Valley posses a large groundwater potential.

  18. September 1985 Mexico City, Mexico Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The magnitude 8.1 earthquake occurred off the Pacific coast of Mexico. The damage was concentrated in a 25 square km area of Mexico City, 350 km from the epicenter....

  19. Subsidence Modeling of the Over-exploited Granular Aquifer System in Aguascalientes, Mexico

    Science.gov (United States)

    Solano Rojas, D. E.; Pacheco, J.; Wdowinski, S.; Minderhoud, P. S. J.; Cabral-Cano, E.; Albino, F.

    2017-12-01

    The valley of Aguascalientes in central Mexico experiences subsidence rates of up to 100 [mm/yr] due to overexploitation of its aquifer system, as revealed from satellite-based geodetic observations. The spatial pattern of the subsidence over the valley is inhomogeneous and affected by shallow faulting. The understanding of the subsoil mechanics is still limited. A better understanding of the subsidence process in Aguascalientes is needed to provide insights for future subsidence in the valley. We present here a displacement-constrained finite-element subsidence model, based on the USGS MODFLOW software. The construction of our model relies on 3 main inputs: (1) groundwater level time series obtained from extraction wells' hydrographs, (2) subsurface lithostratigraphy interpreted from well drilling logs, and (3) hydrogeological parameters obtained from field pumping tests. The groundwater level measurements were converted to pore pressure in our model's layers, and used in Terzaghi's equation for calculating effective stress. We then used the effective stress along with the displacement obtained from geodetic observations to constrain and optimize five geo-mechanical parameters: compression ratio, reloading ratio, secondary compression index, over consolidation ratio, and consolidation coefficient. Finally, we use the NEN-Bjerrum linear stress model formulation for settlements to determine elastic and visco-plastic strain, accounting for the aquifer system units' aging effect. Preliminary results show higher compaction response in clay-saturated intervals (i.e. aquitards) of the aquifer system, as reflected in the spatial pattern of the surface deformation. The forecasted subsidence for our proposed scenarios show a much more pronounced deformation when we consider higher groundwater extraction regimes.

  20. 27 CFR 9.27 - Lime Kiln Valley.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lime Kiln Valley. 9.27... OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.27 Lime Kiln Valley. (a) Name. The name of the viticultural area described in this section is “Lime Kiln Valley...

  1. Estimation of Actual Evapotranspiration along the Middle Rio Grande of New Mexico Using MODIS and Landsat Imagery with the METRIC Model

    OpenAIRE

    Trezza, Ricardo; Allen, Richard; Tasumi, Masahiro

    2013-01-01

    Estimation of actual evapotranspiration (ET) for the Middle Rio Grande valley in central New Mexico via the METRIC surface energy balance model using MODIS and Landsat imagery is described. MODIS images are a useful resource for estimating ET at large scales when high spatial resolution is not required. One advantage of MODIS satellites is that images having a view angle < ~15° are potentially available about every four to five days. The main challenge of applying METRIC using MODIS is the se...

  2. A valley-filtering switch based on strained graphene.

    Science.gov (United States)

    Zhai, Feng; Ma, Yanling; Zhang, Ying-Tao

    2011-09-28

    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device.

  3. A valley-filtering switch based on strained graphene

    International Nuclear Information System (INIS)

    Zhai Feng; Ma Yanling; Zhang Yingtao

    2011-01-01

    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device. (paper)

  4. Electrical valley filtering in transition metal dichalcogenides

    Science.gov (United States)

    Hsieh, Tzu-Chi; Chou, Mei-Yin; Wu, Yu-Shu

    2018-03-01

    This work investigates the feasibility of electrical valley filtering for holes in transition metal dichalcogenides. We look specifically into the scheme that utilizes a potential barrier to produce valley-dependent tunneling rates, and perform the study with both a k .p -based analytic method and a recursive Green's function-based numerical method. The study yields the transmission coefficient as a function of incident energy and transverse wave vector, for holes going through lateral quantum barriers oriented in either armchair or zigzag directions, in both homogeneous and heterogeneous systems. The main findings are the following: (1) The tunneling current valley polarization increases with increasing barrier width or height; (2) both the valley-orbit interaction and band structure warping contribute to valley-dependent tunneling, with the former contribution being manifest in structures with asymmetric potential barriers, and the latter being orientation dependent and reaching maximum for transmission in the armchair direction; and (3) for transmission ˜0.1 , a tunneling current valley polarization of the order of 10 % can be achieved.

  5. TEK and biodiversity management in agroforestry systems of different socio-ecological contexts of the Tehuacán Valley.

    Science.gov (United States)

    Vallejo-Ramos, Mariana; Moreno-Calles, Ana I; Casas, Alejandro

    2016-07-22

    Transformation of natural ecosystems into intensive agriculture is a main factor causing biodiversity loss worldwide. Agroforestry systems (AFS) may maintain biodiversity, ecosystem benefits and human wellbeing, they have therefore high potential for concealing production and conservation. However, promotion of intensive agriculture and disparagement of TEK endanger their permanence. A high diversity of AFS still exist in the world and their potentialities vary with the socio-ecological contexts. We analysed AFS in tropical, temperate, and arid environments, of the Tehuacan Valley, Mexico, to investigate how their capacity varies to conserve biodiversity and role of TEK influencing differences in those contexts. We hypothesized that biodiversity in AFS is related to that of forests types associated and the vigour of TEK and management. We conducted studies in a matrix of environments and human cultures in the Tehuacán Valley. In addition, we reviewed, systematized and compared information from other regions of Mexico and the world with comparable socio-ecological contexts in order to explore possible general patterns. Our study found from 26 % to nearly 90 % of wild plants species richness conserved in AFS, the decreasing proportion mainly associated to pressures for intensifying agricultural production and abandoning traditional techniques. Native species richness preserved in AFS is influenced by richness existing in the associated forests, but the main driver is how people preserve benefits of components and functions of ecosystems. Elements of modern agricultural production may coexist with traditional management patterns, but imposition of modern models may break possible balances. TEK influences decisions on what and how modern techniques may be advantageous for preserving biodiversity, ecosystem integrity in AFS and people's wellbeing. TEK, agroecology and other sciences may interact for maintaining and improving traditional AFS to increase biodiversity

  6. Water resources of Parowan Valley, Iron County, Utah

    Science.gov (United States)

    Marston, Thomas M.

    2017-08-29

    Parowan Valley, in Iron County, Utah, covers about 160 square miles west of the Red Cliffs and includes the towns of Parowan, Paragonah, and Summit. The valley is a structural depression formed by northwest-trending faults and is, essentially, a closed surface-water basin although a small part of the valley at the southwestern end drains into the adjacent Cedar Valley. Groundwater occurs in and has been developed mainly from the unconsolidated basin-fill aquifer. Long-term downward trends in groundwater levels have been documented by the U.S. Geological Survey (USGS) since the mid-1950s. The water resources of Parowan Valley were assessed during 2012 to 2014 with an emphasis on refining the understanding of the groundwater and surface-water systems and updating the groundwater budget.Surface-water discharge of five perennial mountain streams that enter Parowan Valley was measured from 2013 to 2014. The total annual surface-water discharge of the five streams during 2013 to 2014 was about 18,000 acre-feet (acre-ft) compared to the average annual streamflow of about 22,000 acre-ft from USGS streamgages operated on the three largest of these streams from the 1940s to the 1980s. The largest stream, Parowan Creek, contributes more than 50 percent of the annual surface-water discharge to the valley, with smaller amounts contributed by Red, Summit, Little, and Cottonwood Creeks.Average annual recharge to the Parowan Valley groundwater system was estimated to be about 25,000 acre-ft from 1994 to 2013. Nearly all recharge occurs as direct infiltration of snowmelt and rainfall on the Markagunt Plateau east of the valley. Smaller amounts of recharge occur as infiltration of streamflow and unconsumed irrigation water near the east side of the valley on alluvial fans associated with mountain streams at the foot of the Red Cliffs. Subsurface flow from the mountain block to the east of the valley is a significant source of groundwater recharge to the basin-fill aquifer

  7. EPA Region 1 - Valley Depth in Meters

    Science.gov (United States)

    Raster of the Depth in meters of EPA-delimited Valleys in Region 1.Valleys (areas that are lower than their neighbors) were extracted from a Digital Elevation Model (USGS, 30m) by finding the local average elevation, subtracting the actual elevation from the average, and selecting areas where the actual elevation was below the average. The landscape was sampled at seven scales (circles of 1, 2, 4, 7, 11, 16, and 22 km radius) to take into account the diversity of valley shapes and sizes. Areas selected in at least four scales were designated as valleys.

  8. Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

    Science.gov (United States)

    Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

    2017-07-19

    The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of Los Angeles, California, in the western part of the Mojave Desert. These basins have been adjudicated to ensure that groundwater rights are allocated according to legal judgments. In an effort to assess if the boundary between the Antelope Valley and El Mirage Valley groundwater basins could be better defined, the U.S. Geological Survey began a cooperative study in 2014 with the Mojave Water Agency to better understand the hydrogeology in the area and investigate potential controls on groundwater flow and availability, including basement topography.Recharge is sporadic and primarily from small ephemeral washes and streams that originate in the San Gabriel Mountains to the south; estimates range from about 400 to 1,940 acre-feet per year. Lateral underflow from adjacent basins has been considered minor in previous studies; underflow from the Antelope Valley to the El Mirage Valley groundwater basin has been estimated to be between 100 and 1,900 acre-feet per year. Groundwater discharge is primarily from pumping, mostly by municipal supply wells. Between October 2013 and September 2014, the municipal pumpage in the Antelope Valley and El Mirage Valley groundwater basins was reported to be about 800 and 2,080 acre-feet, respectively.This study was motivated by the results from a previously completed regional gravity study, which suggested a northeast-trending subsurface basement ridge and saddle approximately 3.5 miles west of the boundary between the Antelope Valley and El Mirage Valley groundwater basins that might influence groundwater flow. To better define potential basement

  9. Optically initialized robust valley-polarized holes in monolayer WSe2

    KAUST Repository

    Hsu, Wei-Ting

    2015-11-25

    A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin–valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (~10–20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.

  10. Valley-orbit hybrid states in Si quantum dots

    Science.gov (United States)

    Gamble, John; Friesen, Mark; Coppersmith, S. N.

    2013-03-01

    The conduction band for electrons in layered Si nanostructures oriented along (001) has two low-lying valleys. Most theoretical treatments assume that these valleys are decoupled from the long-wavelength physics of electron confinement. In this work, we show that even a minimal amount of disorder (a single atomic step at the quantum well interface) is sufficient to mix valley states and electron orbitals, causing a significant distortion of the long-wavelength electron envelope. For physically realistic electric fields and dot sizes, this valley-orbit coupling impacts all electronic states in Si quantum dots, implying that one must always consider valley-orbit hybrid states, rather than distinct valley and orbital degrees of freedom. We discuss the ramifications of our results on silicon quantum dot qubits. This work was supported in part by ARO (W911NF-08-1-0482) and NSF (DMR-0805045).

  11. Geohydrology of the Unconsolidated Valley-Fill Aquifer in the Meads Creek Valley, Schuyler and Steuben Counties, New York

    Science.gov (United States)

    Miller, Todd S.; Bugliosi, Edward F.; Reddy, James E.

    2008-01-01

    The Meads Creek valley encompasses 70 square miles of predominantly forested uplands in the upper Susquehanna River drainage basin. The valley, which was listed as a Priority Waterbody by the New York State Department of Environmental Conservation in 2004, is prone to periodic flooding, mostly in its downstream end, where development is occurring most rapidly. Hydraulic characteristics of the unconsolidated valley-fill aquifer were evaluated, and seepage rates in losing and gaining tributaries were calculated or estimated, in an effort to delineate the aquifer geometry and identify the factors that contribute to flooding. Results indicated that (1) Meads Creek gained about 61 cubic feet of flow per second (about 6.0 cubic feet per second per mile of stream channel) from ground-water discharge and inflow from tributaries in its 10.2-mile reach between the northernmost and southernmost measurement sites; (2) major tributaries in the northern part of the valley are not significant sources of recharge to the aquifer; and (3) major tributaries in the central and southern part of the valley provide recharge to the aquifer. The ground-water portion of streamflow in Meads Creek (excluding tributary inflow) was 11.3 cubic feet per second (ft3/s) in the central part of the valley and 17.2 ft3/s in the southern part - a total of 28.5 ft3/s. Ground-water levels were measured in 29 wells finished in unconfined deposits for construction of a potentiometric-surface map to depict directions of ground-water flow within the valley. In general, ground water flows from the edges of the valley toward Meads Creek and ultimately discharges to it. The horizontal hydraulic gradient for the entire 12-mile-long aquifer averages about 30 feet per mile, whereas the gradient in the southern fourth of the valley averages about half that - about 17 feet per mile. A water budget for the aquifer indicated that 28 percent of recharge was derived from precipitation that falls on the aquifer, 32

  12. Powering Mexico

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This article examines Mexico's demand for electricity and the market for independent power generation. The topics discussed in the article include the outlook for the 1990s for growth in Mexico's economy and energy demand, renewable energy, energy conservation, small-scale, off-grid renewable energy systems, and estimates of Mexico's market for electric power generating equipment

  13. California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley

    Science.gov (United States)

    Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

    2009-01-01

    Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

  14. Valley and spin thermoelectric transport in ferromagnetic silicene junctions

    International Nuclear Information System (INIS)

    Ping Niu, Zhi; Dong, Shihao

    2014-01-01

    We have investigated the valley and spin resolved thermoelectric transport in a normal/ferromagnetic/normal silicene junction. Due to the coupling between the valley and spin degrees of freedom, thermally induced pure valley and spin currents can be demonstrated. The magnitude and sign of these currents can be manipulated by adjusting the ferromagnetic exchange field and local external electric field, thus the currents are controllable. We also find fully valley and/or spin polarized currents. Similar to the currents, owing to the band structure symmetry, tunable pure spin and/or valley thermopowers with zero charge counterpart are generated. The results obtained here suggest a feasible way of generating a pure valley (spin) current and thermopower in silicene

  15. The obsidian of the Maltrata valley, Veracruz, origin analysis of the raw material with neutron activation analysis

    International Nuclear Information System (INIS)

    Molina V, R. O.; Jimenez R, M.; Tenorio, D.; Lira L, Y.; Manzanilla, L.

    2009-01-01

    51 archaeological pieces of obsidian coming from the Maltrata valley were analyzed by means of the analysis technique by neutron activation, with the purpose of determining the interchange routes of that region. In accordance with the statistical study of the results, the obsidians of this investigation come from 5 deposits located in: Sierra de las Navajas, Pico de Orizaba, Zaragoza-Oyameles, Otumba and Paredon. The analyzed obsidian fragments were selected in accordance with their raw material type, size, weight, morphology, excavation context and surface. The irradiation of the samples was carried out in the research reactor TRIGA Mark III of the Nuclear Center of Mexico, with a neutrons flow of 1·10 13 n·cm -2 ·s -1 . (Author)

  16. Engineering assessment of inactive uranium mill tailings: Monument Valley Site, Monument Valley, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    1981-10-01

    Ford, Bacon and Davis Utah Inc. has reevalated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposure of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through IV). Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching; Treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovery is economically unattractive.

  17. Engineering assessment of inactive uranium mill tailings: Monument Valley Site, Monument Valley, Arizona

    International Nuclear Information System (INIS)

    1981-10-01

    Ford, Bacon and Davis Utah Inc. has reevalated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposure of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through IV). Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching; Treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovery is economically unattractive

  18. Effects of riparian vegetation on topographic change during a large flood event, Rio Puerco, New Mexico, USA

    Science.gov (United States)

    Perignon, M. C.; Tucker, G. E.; Griffin, E. R.; Friedman, J. M.

    2013-09-01

    The spatial distribution of riparian vegetation can strongly influence the geomorphic evolution of dryland rivers during large floods. We present the results of an airborne lidar differencing study that quantifies the topographic change that occurred along a 12 km reach of the Lower Rio Puerco, New Mexico, during an extreme event in 2006. Extensive erosion of the channel banks took place immediately upstream of the study area, where tamarisk and sandbar willow had been removed. Within the densely vegetated study reach, we measure a net volumetric change of 578,050 ± ˜ 490,000 m3, with 88.3% of the total aggradation occurring along the floodplain and channel and 76.7% of the erosion focusing on the vertical valley walls. The sediment derived from the devegetated reach deposited within the first 3.6 km of the study area, with depth decaying exponentially with distance downstream. Elsewhere, floodplain sediments were primarily sourced from the erosion of valley walls. Superimposed on this pattern are the effects of vegetation and valley morphology on sediment transport. Sediment thickness is seen to be uniform among sandbar willows and highly variable within tamarisk groves. These reach-scale patterns of sedimentation observed in the lidar differencing likely reflect complex interactions of vegetation, flow, and sediment at the scale of patches to individual plants.

  19. Chapter 2. Assessment of undiscovered conventional oil and gas resources--Upper Jurassic-Lower Cretaceous Cotton Valley group, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

    Science.gov (United States)

    Dyman, T.S.; Condon, S.M.

    2006-01-01

    The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover Formation carbonates and calcareous shales and (2) Upper Jurassic and Lower Cretaceous Cotton Valley Group organic-rich shales. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes four conventional Cotton Valley assessment units: Cotton Valley Blanket Sandstone Gas (AU 50490201), Cotton Valley Massive Sandstone Gas (AU 50490202), Cotton Valley Updip Oil and Gas (AU 50490203), and Cotton Valley Hypothetical Updip Oil (AU 50490204). Together, these four assessment units are estimated to contain a mean undiscovered conventional resource of 29.81 million barrels of oil, 605.03 billion cubic feet of gas, and 19.00 million barrels of natural gas liquids. The Cotton Valley Group represents the first major influx of clastic sediment into the ancestral Gulf of Mexico. Major depocenters were located in south-central Mississippi, along the Louisiana-Mississippi border, and in northeast Texas. Reservoir properties and production characteristics were used to identify two Cotton Valley Group sandstone trends across northern Louisiana and east Texas: a high-permeability blanket-sandstone trend and a downdip, low-permeability massive-sandstone trend. Pressure gradients throughout most of both trends are normal, which is characteristic of conventional rather than continuous basin-center gas accumulations. Indications that accumulations in this trend are conventional rather than continuous include (1) gas-water contacts in at least seven fields across the blanket-sandstone trend, (2) relatively high reservoir permeabilities, and (3) high gas-production rates without fracture stimulation. Permeability is sufficiently low in the massive-sandstone trend that gas-water transition zones are vertically extensive and gas-water contacts are poorly defined. The interpreted presence of gas-water contacts within the Cotton Valley

  20. Sustainable agricultural development in inland valleys

    NARCIS (Netherlands)

    Zwart, S.J.

    2018-01-01

    The inland valley in Africa are common landscapes that have favorable conditions for agricultural production. Compared to the surrounding uplands they are characterized by a relatively high and secure water availability and high soil fertility levels. Inland valleys thus have a high agricultural

  1. Valley-polarized quantum transport generated by gauge fields in graphene

    Science.gov (United States)

    Settnes, Mikkel; Garcia, Jose H.; Roche, Stephan

    2017-09-01

    We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by the superposition/cancellation of superimposed gauge fields which differently affect time reversal symmetry. The onset of a valley-polarized Hall current concomitant to a dissipative valley-polarized current flow in the opposite valley is revealed by a {{e}2}/h Hall conductivity plateau. We employ efficient linear scaling Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder.

  2. Groundwater availability of the Central Valley Aquifer, California

    Science.gov (United States)

    Faunt, Claudia C.

    2009-01-01

    California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the Central Valley, and about one-fifth of the Nation's groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California's expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley's population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The

  3. History of pedogenesis and geomorphic processes in the Valley of Teotihuacán, Mexico: Micromorphological evidences from a soil catena Historia de la edafogénesis y de los procesos geomorfológicos en el Valle de Teotihuacán, México: evidencias micromorfológicas de una catena de suelos História da pedogénese e dos processos geomorfológicos no Vale de Teotihuacán, México: evidencias micromorfológicas de uma catena de solos

    OpenAIRE

    M. Lourdes González-Arqueros; Lorenzo Vázquez-Selem; Jorge E. Gama Castro; Emily McClung de Tapia; Sergey Sedov

    2013-01-01

    The paper provides new evidence on the pedogeomorphic history of the Valley of Teotihuacán, Mexico. The soil landscape here consists of Luvisol and "black soil", the micromorphology of which allowed us to (a) distinguish between in situ and inherited processes and (b) establish spatial relationships of erosion and sedimentation along a toposequence of three soil profiles. Soil profiles sites were selected by photointerpretation followed by verification on a toposequence from middle mountain s...

  4. Archeological Investigations in Cochiti Reservoir, New Mexico. Volume 4. Adaptive Change in the Northern Rio Grande Valley.

    Science.gov (United States)

    1979-01-01

    remains for the entire to irrigate their gardens of melons, squashes, onions. chiles . Cochiti region, sunflowers, and tomatoes (Clark 1928:234). Thus...red period Glaze decorated wares also occur in northern and are Agua Fria Glaze-on-red, San Clemente Glaze-polychrome, western Mexico and were...modified from Mera 1933) Group TyoeName Etimated Date of Manufacture (A.D. pre-A Los Padillas G-P 71300 to 1325? A Arenal G-P ?1315 to 13507 Agua Fria G/R

  5. An example of Alaknanda valley, Garhwal Himalaya, India

    Indian Academy of Sciences (India)

    2014) have been best explained by the geometry .... flows through narrow valley confined by the steep valley slopes. ... valley (figure 3b) which opens up around Srina- ... Method. 4.1 Drainage basin and stream network. Digital Elevation Model (DEM) helps in extracting ... was processed to fill the pits or sinks, and to obtain.

  6. Brine history indicated by argon, krypton, chlorine, bromine, and iodine analyses of fluid inclusions from the Mississippi Valley type lead-fluorite-barite deposits at Hansonburg, New Mexico

    Science.gov (United States)

    Böhlke, J.K.; Irwin, J.J.

    1992-01-01

    Argon, krypton, chlorine, bromine, and iodine were measured in a homogeneous population of high-salinity hydrothermal fluid inclusions from the Tertiary-age Mississippi Valley-type (MVT) lead-fluorite-barite deposits at Hansonburg, New Mexico to establish new types of evidence for the history of both the fluid and the major dissolved salts. Noble gases and halogens in fluid inclusions containing 10−10–10−9 L of brine (Cl= 3 molal) were analyzed by laser microprobe noble-gas mass spectrometry (lmngms) on neutron-irradiated samples.The concentrations of36Ar (4.7 × 10−8 molal) and84Kr1.8 × 10−9 molal) in the fluid inclusions are equal to those of fresh surface waters in equilibrium with air at approximately20 ± 5°. The mole ratios ofBr/Cl (1.2 × 10−4) andI/Cl (1–2 × 10−6) are among the lowest measured in any natural waters, similar to those of modern brines formed by dissolution of Permian NaCl-bearing evaporites in southeast New Mexico.40Ar/36Ar ratios (600) are twice that of air, and indicate that the fluid inclusions had excess radiogenic40Ar (1.4 × 10−5 molal) when trapped. The amount of excess40Ar appears to be too large to have been acquired with Cl by congruent dissolution of halite-bearing evaporites, and possibly too small to have been acquired with Pb by congruent dissolution of granitic basement rocks with Proterozoic KAr ages.From thelmngms data, combined with published Pb and S isotope data, we infer the following sequence of events in the history of the Hansonburg MVT hydrothermal brine: (1) the brine originated as relatively dilute meteoric water, and it did not gain or lose atmospheric Ar or Kr after recharge; (2) the originally dilute fluid acquired the bulk of its Cl and sulfate in the subsurface after recharge by dissolving halite-bearing Permian? marine evaporites; (3) the high salinity brine then acquired most of its Pb and excess radiogenic40Ar from interactions with aquifer rocks other than evaporites, possibly clastic

  7. Neoproterozoic diamictite-cap carbonate succession and δ13C chemostratigraphy from eastern Sonora, Mexico

    Science.gov (United States)

    Corsetti, Frank A.; Stewart, John H.; Hagadorn, James W.

    2007-01-01

    Despite the occurrence of Neoproterozoic strata throughout the southwestern U.S. and Sonora, Mexico, glacial units overlain by enigmatic cap carbonates have not been well-documented south of Death Valley, California. Here, we describe in detail the first glaciogenic diamictite and cap carbonate succession from Mexico, found in the Cerro Las Bolas Group. The diamictite is exposed near Sahuaripa, Sonora, and is overlain by a 5 m thick very finely-laminated dolostone with soft sediment folds. Carbon isotopic chemostratigraphy of the finely-laminated dolostone reveals a negative δ13C anomaly (down to − 3.2‰ PDB) characteristic of cap carbonates worldwide. Carbon isotopic values rise to + 10‰ across ∼ 400 m of section in overlying carbonates of the Mina el Mezquite and Monteso Formations. The pattern recorded here is mostly characteristic of post-Sturtian (ca. ≤ 700 Ma), but pre-Marinoan (ca. ≥ 635 Ma) time. However, the Cerro Las Bolas Group shares ambiguity common to most Neoproterozoic successions: it lacks useful radiometric age constraints and biostratigraphically useful fossils, and its δ13C signature is oscillatory and therefore somewhat equivocal.

  8. Hydrogeologic and Hydrochemical Studies in a Semi-arid Watershed in Northern Mexico

    Science.gov (United States)

    Kretzschmar, T.; Vazquez, R.; Hinojosa, A.

    2006-12-01

    Within the Baja California panhandle exist quite a significant number of valleys which hydrogeology conditions are of great importance for the communities of the region. The Guadalupe Valley for example, located 30 km Northeast of Ensenada, hosts an important wine industry which presents a mayor factor for agriculture and tourism in Baja California. The irrigation is carried out basically by groundwater extracted from quaternary sediments filling this post-Miocene depression. Besides the intensive usage of the water by the wine industry in the Guadalupe Valley, the local waterworks installed in 1985 a gallery of 10 wells extracting around 320 l/s or 30 % of the total water extraction in the valley to supply the city of Ensenada with drinking water. A total of more than 500 wells with a combined annual consumption of about 28 Mio m3 are at the moment active in the valley. In the arid portions of northern Mexico Mountain front recharge presents an important recharge source for the alluvial aquifers. Other important sources directly related to precipitation are direct infiltration, recharge by surface water runoff in the arroyos as well as by active fault systems. The principal recharge sources for the Guadalupe Valley aquifer are the Sierra Juárez and the Guadalupe River. To be able to address the state of equilibrium of aquifer, recharge estimates for the watershed were calculated determining the runoff/infiltration relationships obtained by curve number determinations combined with the interpretation of satellite images. These results were integrated into an evaluation and hydrologic modeling of the hydrologic data pointing towards differences of up to over 50 percent in the recharge estimation in comparison to earlier studies carried out in the area. Furthermore hydrochemical and isotopic studies were carried out to show the effects of the excessive ground water extraction on the water quality of the aquifer. The hydrochemical data indicate that intense use of

  9. California's restless giant: the Long Valley Caldera

    Science.gov (United States)

    Hill, David P.; Bailey, Roy A.; Hendley, James W.; Stauffer, Peter H.; Marcaida, Mae

    2014-01-01

    Scientists have monitored geologic unrest in the Long Valley, California, area since 1980. In that year, following a swarm of strong earthquakes, they discovered that the central part of the Long Valley Caldera had begun actively rising. Unrest in the area persists today. The U.S. Geological Survey (USGS) continues to provide the public and civil authorities with current information on the volcanic hazard at Long Valley and is prepared to give timely warnings of any impending eruption.

  10. Ozone, area social conditions, and mortality in Mexico City

    International Nuclear Information System (INIS)

    O'Neill, M.S.; Loomis, Dana; Borja-Aburto, V.H.

    2004-01-01

    We investigated whether the association of daily mortality and ambient ozone differs by age and area social conditions of the region of residence using a time-series analysis. The study setting was metropolitan Mexico City, a high altitude city situated in a valley, with an estimated 20 million inhabitants, large socioeconomic gradients, and ozone levels frequently exceeding international standards. We stratified daily deaths by six census-derived socioeconomic indicators, based on characteristics of the county where decedents lived. We used Poisson regression to model the association between daily mortality and ozone levels (on the day of death and the previous day) in separate models, stratified by area socioeconomic level and age, and controlling for time trends and temperature. Ozone was positively associated with total mortality [0.65% increase per 10 ppb increment, 95% confidence interval (CI): 0.02%, 1.28%] and for mortality among those over age 65 [1.39% increase per 10 ppb increment, 95% CI: 0.51%, 2.28%]. Associations between ozone and all-age mortality did not show any consistent patterns according to socioeconomic gradients. We conclude that elderly people are at higher risk for ozone-associated mortality. Though county-level social indicators in Mexico City were not strong markers of vulnerability to ozone-associated acute mortality in this analysis, complex associations between individual and area-level factors may exist that would require additional data and further analyses to elucidate

  11. Valley Fever

    Science.gov (United States)

    ... valley fever. These fungi are commonly found in soil in specific regions. The fungi's spores can be stirred into the air by ... species have a complex life cycle. In the soil, they grow as a mold with long filaments that break off into airborne ...

  12. An international borderland of concern: Conservation of biodiversity in the Lower Rio Grande Valley

    Science.gov (United States)

    Leslie,, David M.

    2016-07-20

    The Lower Rio Grande Valley (LRGV) of southern Texas is located on the United States-Mexico borderland and represents a 240-kilometer (150-mile) linear stretch that ends at the Gulf of Mexico. The LRGV represents a unique transition between temperate and tropical conditions and, as such, sustains an exceptionally high diversity of plants and animals—some of them found in few, or no other, places in the United States. Examples include Leopardus pardalis albescens (northern ocelot) and Falco femoralis septentrionalis (northern aplomado falcon)—both endangered in the United States and emblematic of the LRGV. The U.S. Fish and Wildlife Service (USFWS) manages three national wildlife refuges (Santa Ana, Lower Rio Grande Valley, and Laguna Atascosa) that together make up the South Texas Refuge Complex, which actively conserves biodiversity in about 76,006 hectares (187,815.5 acres) of native riparian and upland habitats in the LRGV. These diminished habitats harbor many rare, threatened, and endangered species. This report updates the widely used 1988 USFWS biological report titled “Tamaulipan Brushland of the Lower Rio Grande Valley of South Texas: Description, Human Impacts, and Management Options” by synthesizing nearly 400 peer-reviewed scientific publications that have resulted from biological and sociological research conducted specifically in the four Texas counties of the LRGV in the past nearly 30 years. This report has three goals: (1) synthesize scientific insights gained since 1988 related to the biology and management of the LRGV and its unique biota, focusing on flora and fauna of greatest conservation concern; (2) update ongoing challenges facing Federal and State agencies and organizations that focus on conservation or key natural resources in the LRGV; and (3) redefine conservation opportunities and land-acquisition strategies that are feasible and appropriate today, given the many new and expanding constraints that challenge conservation

  13. Nematic and Valley Ordering in Anisotropic Quantum Hall Systems

    Science.gov (United States)

    Parameswaran, S. A.; Abanin, D. A.; Kivelson, S. A.; Sondhi, S. L.

    2010-03-01

    We consider a multi-valley two dimensional electron system in the quantum Hall effect (QHE) regime. We focus on QHE states that arise due to spontaneous breaking of the valley symmetry by the Coulomb interactions. We show that the anisotropy of the Fermi surface in each valley, which is generally present in such systems, favors states where all the electrons reside in one of the valleys. In a clean system, the valley ordering occurs via a finite temperature Ising-like phase transition, which, owing to the Fermi surface anisotropy, is accompanied by the onset of nematic order. In a disordered system, domains of opposite polarization are formed, and therefore long-range valley order is destroyed, however, the resulting state is still compressible. We discuss the transport properties in ordered and disordered regimes, and point out the possible relation of our results to recent experiments in AlAs [1]. [1] Y. P. Shkolnikov, S. Misra, N. C. Bishop, E. P. De Poortere, and M. Shayegan, Observation of Quantum Hall ``Valley Skyrmions", Phys. Rev. Lett. 95, 068809 (2005)[2] D.A. Abanin, S.A. Parameswaran, S.A. Kivelson and S.L. Sondhi, Nematic and Valley Ordering in Anisotropic Quantum Hall Systems, to be published.

  14. Customer Need ́s Satisfaction in the Housing Sector: the Case of the Toluca Valley

    Directory of Open Access Journals (Sweden)

    Delgado-Hernández David Joaquín

    2013-10-01

    Full Text Available Currently, the construction sector faces great challenges, as the recent economic contraction has directly impacted this industry, and only companies that can offer quality products and services will survive in today’s highly competitive markets. In particular, the housing sector has to find ways to meet the needs of its customers due to the number of firms competing in this arena. There are some studies that quantify the demand for housing as well as those that reveal the number of homes sold per year in a region. However, investigations in Mexico to establish the level of cus- tomer satisfaction with their homes are still scarce. Thus, the main objective of this research is to determine the level of customer satisfaction in the Toluca Valley ́s housing sector (a region located 60 km west of Mexico City, in low income projects developed by Mexican construction companies. Having applied a questionnaire to users from seventy eight houses within eight different projects, some issues were identified that builders could improve, and take into account during the design stage of new housing developments. Among the main ones are: insulation, wall and ceil- ing materials, space distribution, and house ́s size. In contrast, residents are rela- tively satisfied with: the ease of cleaning, the aesthetics of the projects and the proximity to schools and supermarkets.

  15. Valley photonic crystals for control of spin and topology.

    Science.gov (United States)

    Dong, Jian-Wen; Chen, Xiao-Dong; Zhu, Hanyu; Wang, Yuan; Zhang, Xiang

    2017-03-01

    Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley-spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.

  16. The results of the Seismic Alert System of Mexico SASMEX, during the earthquakes of 7 and 19 of September 2017

    Science.gov (United States)

    Espinosa Aranda, J. M., Sr.; Cuellar Martinez, A.

    2017-12-01

    of Mexico City, reported absolute accelerations of 225 cm/s2 in the transition soils , which have never recorded in the Mexico Valley.

  17. Valley Hall effect and Nernst effect in strain engineered graphene

    Science.gov (United States)

    Niu, Zhi Ping; Yao, Jian-ming

    2018-04-01

    We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.

  18. Disorder-dependent valley properties in monolayer WSe2

    KAUST Repository

    Tran, Kha

    2017-07-19

    We investigate the effect of disorder on exciton valley polarization and valley coherence in monolayer WSe2. By analyzing the polarization properties of photoluminescence, the valley coherence (VC) and valley polarization (VP) are quantified across the inhomogeneously broadened exciton resonance. We find that disorder plays a critical role in the exciton VC, while affecting VP less. For different monolayer samples with disorder characterized by their Stokes shift (SS), VC decreases in samples with higher SS while VP does not follow a simple trend. These two methods consistently demonstrate that VC as defined by the degree of linearly polarized photoluminescence is more sensitive to disorder, motivating further theoretical studies.

  19. The Role of Source Material in Basin Sedimentation, as Illustrated within Eureka Valley, Death Valley National Park, CA.

    Science.gov (United States)

    Lawson, M. J.; Yin, A.; Rhodes, E. J.

    2015-12-01

    Steep landscapes are known to provide sediment to sink regions, but often petrological factors can dominate basin sedimentation. Within Eureka Valley, in northwestern Death Valley National Park, normal faulting has exposed a steep cliff face on the western margin of the Last Chance range with four kilometers of vertical relief from the valley floor and an angle of repose of nearly 38 degrees. The cliff face is composed of Cambrian limestone and dolomite, including the Bonanza King, Carrara and Wood Canyon formations. Interacting with local normal faulting, these units preferentially break off the cliff face in coherent blocks, which result in landslide deposits rather than as finer grained material found within the basin. The valley is well known for a large sand dune, which derives its sediment from distal sources to the north, instead of from the adjacent Last Chance Range cliff face. During the Holocene, sediment is sourced primary from the northerly Willow Wash and Cucomungo canyon, a relatively small drainage (less than 80 km2) within the Sylvan Mountains. Within this drainage, the Jurassic quartz monzonite of Beer Creek is heavily fractured due to motion of the Fish Valley Lake - Death Valley fault zone. Thus, the quartz monzonite is more easily eroded than the well-consolidated limestone and dolomite that forms the Last Change Range cliff face. As well, the resultant eroded material is smaller grained, and thus more easily transported than the limestone. Consequently, this work highlights an excellent example of the strong influence that source material can have on basin sedimentation.

  20. Evolution under domestication: ongoing artificial selection and divergence of wild and managed Stenocereus pruinosus (Cactaceae) populations in the Tehuacán Valley, Mexico

    Science.gov (United States)

    Parra, Fabiola; Casas, Alejandro; Peñaloza-Ramírez, Juan Manuel; Cortés-Palomec, Aurea C.; Rocha-Ramírez, Víctor; González-Rodríguez, Antonio

    2010-01-01

    Background and Aims The Tehuacán Valley in Mexico is a principal area of plant domestication in Mesoamerica. There, artificial selection is currently practised on nearly 120 native plant species with coexisting wild, silvicultural and cultivated populations, providing an excellent setting for studying ongoing mechanisms of evolution under domestication. One of these species is the columnar cactus Stenocereus pruinosus, in which we studied how artificial selection is operating through traditional management and whether it has determined morphological and genetic divergence between wild and managed populations. Methods Semi-structured interviews were conducted with 83 households of three villages to investigate motives and mechanisms of artificial selection. Management effects were studied by comparing variation patterns of 14 morphological characters and population genetics (four microsatellite loci) of 264 plants from nine wild, silvicultural and cultivated populations. Key Results Variation in fruit characters was recognized by most people, and was the principal target of artificial selection directed to favour larger and sweeter fruits with thinner or thicker peel, fewer spines and pulp colours others than red. Artificial selection operates in agroforestry systems favouring abundance (through not felling plants and planting branches) of the preferred phenotypes, and acts more intensely in household gardens. Significant morphological divergence between wild and managed populations was observed in fruit characters and plant vigour. On average, genetic diversity in silvicultural populations (HE = 0·743) was higher than in wild (HE = 0·726) and cultivated (HE = 0·700) populations. Most of the genetic variation (90·58 %) occurred within populations. High gene flow (NmFST > 2) was identified among almost all populations studied, but was slightly limited by mountains among wild populations, and by artificial selection among wild and managed populations. Conclusions

  1. Psychology in Mexico

    Science.gov (United States)

    Ruiz, Eleonora Rubio

    2011-01-01

    The first formal psychology course taught in Mexico was in 1896 at Mexico's National University; today, National Autonomous University of Mexico (UNAM in Spanish). The modern psychology from Europe and the US in the late 19th century were the primary influences of Mexican psychology, as well as psychoanalysis and both clinical and experimental…

  2. Antifan activism as a response to MTV's The Valleys

    Directory of Open Access Journals (Sweden)

    Bethan Jones

    2015-06-01

    Full Text Available MTV has launched several reality TV shows in the United Kingdom, but one, The Valleys (2012–14, about youth moving from the South Wales Valleys to Cardiff, has received much criticism. Grassroots criticism of the show arose, and a Valleys-centric campaign, The Valleys Are Here, took direct action. I adopt Jonathan Gray's definition of antifans to complicate ideas of fan activism. I utilize comments and posts made on the Valleys Are Here Twitter feed and Facebook account, as well as the organization's Web site, to examine the ways in which they encourage activism among antifans of the series. I pay particular attention to activist calls for MTV to be held accountable for its positioning of Wales and the Valleys, and to how it encourages participation among varied groups of people whose common denominator is their dislike of the series. Fan activism is not exclusive to people who consider themselves fans, and notions of fan activism can be complicated by drawing in antifans.

  3. The quasi-steady state of the valley wind system

    Directory of Open Access Journals (Sweden)

    Juerg eSchmidli

    2015-12-01

    Full Text Available The quasi-steady-state limit of the diurnal valley wind system is investigated overidealized three-dimensional topography. Although this limit is rarely attained inreality due to ever-changing forcings, the investigation of this limit canprovide valuable insight, in particular on the mass and heat fluxes associatedwith the along-valley wind. We derive a scaling relation for the quasi-steady-state along-valleymass flux as a function of valley geometry, valley size, atmospheric stratification,and surface sensible heat flux forcing. The scaling relation is tested by comparisonwith the mass flux diagnosed from numerical simulations of the valleywind system. Good agreement is found. The results also provide insight into the relationbetween surface friction and the strength of the along-valley pressure gradient.

  4. Direct measurement of exciton valley coherence in monolayer WSe2

    KAUST Repository

    Hao, Kai

    2016-02-29

    In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge or spin. Interest in valleytronics has been revived in recent years following the discovery of atomically thin materials such as graphene and transition metal dichalcogenides. However, the valley coherence time—a crucial quantity for valley pseudospin manipulation—is difficult to directly probe. In this work, we use two-dimensional coherent spectroscopy to resonantly generate and detect valley coherence of excitons (Coulomb-bound electron–hole pairs) in monolayer WSe2 (refs ,). The imposed valley coherence persists for approximately one hundred femtoseconds. We propose that the electron–hole exchange interaction provides an important decoherence mechanism in addition to exciton population recombination. This work provides critical insight into the requirements and strategies for optical manipulation of the valley pseudospin for future valleytronics applications.

  5. Photon wavelength dependent valley photocurrent in multilayer MoS2

    Science.gov (United States)

    Guan, Hongming; Tang, Ning; Xu, Xiaolong; Shang, LiangLiang; Huang, Wei; Fu, Lei; Fang, Xianfa; Yu, Jiachen; Zhang, Caifeng; Zhang, Xiaoyue; Dai, Lun; Chen, Yonghai; Ge, Weikun; Shen, Bo

    2017-12-01

    The degree of freedom (DOF) of the K (K') valley in transition-metal dichalcogenides, especially molybdenum disulfide (MoS2), offers an opportunity for next-generation valleytronics devices. In this work, the K (K') valley DOF of multilayer MoS2 is studied by means of the photon wavelength dependent circular photogalvanic effect (CPGE) at room temperature upon a strong external out-of-plane electric field induced by an ionic liquid (IL) gate, which breaks the spatial-inversion symmetry. It is demonstrated that only on resonant excitations in the K (K') valley can the valley-related CPGE signals in multilayer MoS2 with an IL gate be detected, indicating that the valley contrast is indeed regenerated between the K and K' valleys when the electric field is applied. As expected, it can also be seen that the K (K') valley DOF in multilayer MoS2 can be modulated by the external electric field. The observation of photon wavelength dependent valley photocurrent in multilayer MoS2, with the help of better Ohmic contacts, may pave a way for optoelectronic applications of valleytronics in the future.

  6. Spin-valley splitting of electron beam in graphene

    Directory of Open Access Journals (Sweden)

    Yu Song

    2016-11-01

    Full Text Available We study spatial separation of the four degenerate spin-valley components of an electron beam in a EuO-induced and top-gated ferromagnetic/pristine/strained graphene structure. We show that, in a full resonant tunneling regime for all beam components, the formation of standing waves can lead sudden phase jumps ∼−π and giant lateral Goos-Hänchen shifts as large as the transverse beam width, while the interplay of the spin and valley imaginary wave vectors in the modulated regions can lead differences of resonant angles for the four spin-valley flavors, manifesting a spin-valley beam splitting effect. The splitting effect is found to be controllable by the gating and strain.

  7. Pink bollworm integrated management using sterile insects under field trial conditions, Imperial Valley, California

    International Nuclear Information System (INIS)

    Walters, M.L.; Staten, R.T.; Roberson, R.C.

    2000-01-01

    The pink bollworm moth (Pectinophora gossypiella Saunders) feeds almost exclusively on cotton (Gossypium spp.) and causes economic loss (Pfadt 1978). The pink bollworm (PBW) is often the key pest of cotton in Arizona, southern California, and northwestern Mexico. The larvae (immature stages) bore into the developing cotton fruit, where they feed on the cotton lint and seeds, causing significant damage and dramatically reducing the yield of cotton lint (Pfadt 1978). The PBW is difficult to control with conventional means (insecticides) because it spends the destructive larval phase inside the cotton boll where it is well protected from control measures. Cultural controls, such as a short growing season, have successfully decreased the population in the Imperial Valley (Chu et al. 1992) to the point where eradication may be possible using sterile insects and genetically engineered cotton. Because the PBW is an introduced insect, with few plant hosts other than cultivated cotton, its eradication from continental USA is a desirable and economically attractive alternative to the continued use of pesticides and/or further loss to the pest. Mass releases of sterile insects began in earnest in 1970 in the San Joaquin Valley, California, in order to inhibit normal reproduction and to eradicate the pest in an environmentally responsible manner. Sterile release involves mass production and sexual sterilisation using irradiation (20 krad for PBW adults). This was accomplished by building a rearing facility in Phoenix, AZ. The facility has 6,410 square metres of permanent laboratories, rearing and irradiation chambers and insect packing rooms. The facility operates the year round but with a variable production rate, that is, maximal during the cotton growing season (May through September). Sterile insect technology is based on the monitoring of the native and sterile populations in the field and the subsequent release of appropriate numbers of sterile insects in order to

  8. The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

    International Nuclear Information System (INIS)

    Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

    2013-01-01

    Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

  9. 75 FR 28555 - Executive Green ICT & Energy Efficiency Trade Mission to Mexico City, Mexico

    Science.gov (United States)

    2010-05-21

    ... Trade Mission to Mexico City, Mexico AGENCY: International Trade Administration, Department of Commerce... Trade Mission to Mexico City from September 27-29, 2010. This Executive led mission will focus on... & Energy Efficiency conference will take place at the World Trade Center in Mexico City. Relevant issues on...

  10. Opportunity for America: Mexico`s coal future

    Energy Technology Data Exchange (ETDEWEB)

    Loose, V.W.

    1993-09-01

    This study examines the history, current status and future prospects for increased coal use in Mexico. Environmental implications of the power-generation capacity expansion plans are examined in general terms. Mexican environmental law and regulations are briefly reviewed along with the new sense of urgency in the cleanup of existing environmental problems and avoidance of new problems as clearly mandated in recent Mexican government policy initiatives. It is expected that new capital facilities will need to incorporate the latest in process and technology to comply with existing environmental regulation. Technology developments which address these issues are identified. What opportunities have new initiatives caused by the recent diversification of Mexico`s energy economy offered US firms? This report looks at the potential future use of coal in the Mexican energy economy, examining this issue with an eye toward identifying markets that might be available to US coal producers and the best way to approach them. Market opportunities are identified by examining new developments in the Mexican economy generally and the energy economy particularly. These developments are examined in light of the current situation and the history which brought Mexico to its present status.

  11. Valley-polarized quantum transport generated by gauge fields in graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Garcia, Jose H; Roche, Stephan

    2017-01-01

    We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by t...... Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder....

  12. Electrical control of the anomalous valley Hall effect in antiferrovalley bilayers

    Science.gov (United States)

    Tong, Wen-Yi; Duan, Chun-Gang

    2017-08-01

    In analogy to all-electric spintronics, all-electric valleytronics, i.e., valley manipulation via electric means, becomes an exciting new frontier as it may bring revolutions in the field of data storage with ultra-high speed and ultra-low power consumption. The existence of the anomalous valley Hall effect in ferrovalley materials demonstrates the possibility of electrical detection for valley polarization. However, in previously proposed valley-polarized monolayers, the anomalous valley Hall effect is controlled by external magnetic fields. Here, through elaborate structural design, we propose the antiferrovally bilayer as an ideal candidate for realizing all-electric valleytronic devices. Using the minimal k.p model, we show that the energy degeneracy between valley indexes in such system can be lifted by electric approaches. Subsequently, the anomalous valley Hall effect strongly depends on the electric field as well. Taking the bilayer VSe2 as an example, all-electric tuning and detecting of anomalous valley Hall effect is confirmed by density-functional theory calculations, indicating that the valley information in such antiferrovalley bilayer can be reversed by an electric field perpendicular to the plane of the system and easily probed through the sign of the Hall voltage.

  13. Titan's fluvial valleys: Morphology, distribution, and spectral properties

    Science.gov (United States)

    Langhans, M.H.; Jaumann, R.; Stephan, K.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Baines, K.H.; Nicholson, P.D.; Lorenz, R.D.; Soderblom, L.A.; Soderblom, J.M.; Sotin, Christophe; Barnes, J.W.; Nelson, R.

    2012-01-01

    Titan's fluvial channels have been investigated based on data obtained by the Synthetic Aperture Radar (SAR) instrument and the Visible and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. In this paper, a database of fluvial features is created based on radar-SAR data aiming to unveil the distribution and the morphologic and spectral characteristics of valleys on Titan on a global scale. It will also study the spatial relations between fluvial valleys and Titan's geologic units and spectral surface units which have become accessible thanks to Cassini-VIMS data. Several distinct morphologic types of fluvial valleys can be discerned by SAR-images. Dendritic valley networks appear to have much in common with terrestrial dendritic systems owing to a hierarchical and tree-shaped arrangement of the tributaries which is indicative of an origin from precipitation. Dry valleys constitute another class of valleys resembling terrestrial wadis, an indication of episodic and strong flow events. Other valley types, such as putative canyons, cannot be correlated with rainfall based on their morphology alone, since it cannot be ruled out that they may have originated from volcanic/tectonic action or groundwater sapping. Highly developed and complex fluvial networks with channel lengths of up to 1200 km and widths of up to 10 km are concentrated only at a few locations whereas single valleys are scattered over all latitudes. Fluvial valleys are frequently found in mountainous areas. Some terrains, such as equatorial dune fields and undifferentiated plains at mid-latitudes, are almost entirely free of valleys. Spectrally, fluvial terrains are often characterized by a high reflectance in each of Titan's atmospheric windows, as most of them are located on Titan's bright 'continents'. Nevertheless, valleys are spatially associated with a surface unit appearing blue due to its higher reflection at 1.3??m in a VIMS false color RGB composite with R: 1.59/1.27??m, G: 2

  14. Groundwater quality in Coachella Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to

  15. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    Science.gov (United States)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  16. Case-control study of pleural mesothelioma in workers with social security in Mexico.

    Science.gov (United States)

    Aguilar-Madrid, Guadalupe; Robles-Pérez, Eduardo; Juárez-Pérez, Cuauhtémoc Arturo; Alvarado-Cabrero, Isabel; Rico-Méndez, Flavio Gerardo; Javier, Kelly-García

    2010-03-01

    Environmental and occupational exposure to asbestos in Mexico in the past has been a cause of deaths and health damages. Its magnitude is unknown to date. Our objective was to identify the proportion of cases of malignant pleural mesothelioma (MPM) that can be attributed to and occupational exposure to asbestos. We carried out a case-control study of MPM in 472 workers insured by the Mexican Institute of Social Security, all Valley of Mexico residents, with 119 incident cases and 353 controls. Cases were histologically confirmed. Participants were questioned concerning their occupational history and sociodemographic data. Assignment to one of the four exposures was performed qualitatively by an expert hygienist. Odds ratios (ORs) and attributable risks (ARs) were calculated using a non-conditional logistic regression model. A total of 80.6% of cases and 31.5% of controls had occupational exposure to asbestos. ORs were adjusted for age and gender and by exposure category, and exhibited an increase with probability of exposure as follows: 3.7(95% CI 1.3-10.4) for the likely category and 14.3(95% CI 8-26) for the certain category; AR in the group occupationally exposed to asbestos was 83.2%, and the population AR was 44%. Our results show that the relationship between industrial uses of all forms of asbestos is generating an increase in mesothelioma-related diseases and deaths among Mexican workers. As a public health policy, Mexico should prohibit the use of asbestos in all production processes with the aim of controlling the epidemic and preventing the occurrence of new cases of MPM. 2009 Wiley-Liss, Inc.

  17. Plant management and biodiversity conservation in Náhuatl homegardens of the Tehuacán Valley, Mexico.

    Science.gov (United States)

    Larios, Carolina; Casas, Alejandro; Vallejo, Mariana; Moreno-Calles, Ana Isabel; Blancas, José

    2013-11-06

    The Tehuacán Valley is one of the areas of Mesoamerica with the oldest history of plant management. Homegardens are among the most ancient management systems that currently provide economic benefits to people and are reservoirs of native biodiversity. Previous studies estimated that 30% of the plant richness of homegardens of the region are native plant species from wild populations. We studied in Náhuatl communities the proportion of native plant species maintained in homegardens, hypothesizing to find a proportion similar to that estimated at regional level, mainly plant resources maintained for edible, medicinal and ornamental purposes. We analysed the composition of plant species of homegardens and their similarity with surrounding Cloud Forest (CF), Tropical Rainforest (TRF), Tropical Dry forest (TDF), and Thorn-Scrub Forest (TSF). We determined density, frequency and biomass of plant species composing homegardens and forests through vegetation sampling of a total of 30 homegardens and nine plots of forests, and documented ethnobotanical information on use, management, and economic benefits from plants maintained in homegardens. A total of 281 plant species was recorded with 12 use categories, 115 ornamental, 92 edible, and 50 medicinal plant species. We recorded 49.8 ± 23.2 (average ± S.D.) woody plant species (shrubs and trees) per homegarden. In total, 34% species are native to the Tehuacán Valley and nearly 16% are components of the surrounding forests. A total of 176 species were cultivated through seeds, vegetative propagules or transplanted entire individual plants, 71 tolerated, and 23 enhanced. The highest species richness and diversity were recorded in homegardens from the CF zone (199 species), followed by those from the TRF (157) and those from the TDF (141) zones. Homegardens provide a high diversity of resources for subsistence of local households and significantly contribute to conservation of native biodiversity. The highest diversity was

  18. U.S.-Mexico energy

    International Nuclear Information System (INIS)

    1991-05-01

    This paper reports that while Mexico's petrochemical industry has grown rapidly, it now faces shortages both in investment funds and in supplies of basic petrochemicals due to a financial crisis in the 1980s. Mexico has undertaken a series of policy reforms aimed at encouraging foreign and private investment, but these efforts have generally failed to entice U.S. investment in Mexico. U.S. petrochemical companies have cited unfavorable market conditions, insufficient basic petrochemical capacity in Mexico, concern about the reversibility of Mexican reforms, inadequate Mexican protection of intellectual property rights, and lack of investment protection for U.S. businesses as impediments to investment in Mexico. Cooperation between the two nations in overcoming these obstacles could help U.S. petrochemical companies maintain their positions in a competitive global market, while at the same time provide Mexico with much needed capital investment and technological expertise

  19. Comparative lahar hazard mapping at Volcan Citlaltépetl, Mexico using SRTM, ASTER and DTED-1 digital topographic data

    Science.gov (United States)

    Hubbard, Bernard E.; Sheridan, Michael F.; Carrasco-Nunez, Gerardo; Diaz-Castellon, Rodolfo; Rodriguez, Sergio R.

    2007-01-01

    In this study, we evaluated and compared the utility of spaceborne SRTM and ASTER DEMs with baseline DTED-1 “bald-earth” topography for mapping lahar inundation hazards from volcan Citlaltépetl, Mexico, a volcano which has had a history of producing debris flows of various extents. In particular, we tested the utility of these topographic datasets for resolving ancient valley-filling deposits exposed around the flanks of the volcano, for determining their magnitude using paleohydrologic methods and for forecasting their inundation limits in the future. We also use the three datasets as inputs to a GIS stream inundation flow model, LAHARZ, and compare the results.

  20. Mexico and Central America.

    Science.gov (United States)

    Bronfman, M

    1998-01-01

    This article reviews the literature on migration and HIV/AIDS in Mexico and Central America, including Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama. Most migrants travel to the US through Mexico. US-Mexico trade agreements created opportunities for increased risk of HIV transmission. The research literature focuses on Mexico. Most countries, with the exception of Belize and Costa Rica, are sending countries. Human rights of migrants are violated in transit and at destination. Migration policies determine migration processes. The Mexican-born population in the US is about 3% of US population and 8% of Mexico's population. About 22% arrived during 1992-97, and about 500,000 are naturalized US citizens. An additional 11 million have a Mexican ethnic background. Mexican migrants are usually economically active men who had jobs before leaving and were urban people who settled in California, Texas, Illinois, and Arizona. Most Mexican migrants enter illegally. Many return to Mexico. The main paths of HIV transmission are homosexual, heterosexual, and IV-drug-injecting persons. Latino migrants frequently use prostitutes, adopt new sexual practices including anal penetration among men, greater diversity of sexual partners, and use of injectable drugs.

  1. EPA Region 1 - Map Layers for Valley ID Tool (Hosted Feature Service)

    Science.gov (United States)

    The Valley Service Feature Layer hosts spatial data for EPA Region 1's Valley Identification Tool. These layers contain attribute information added by EPA R1 GIS Center to help identify populated valleys:- Fac_2011NEI: Pollution sources selected from the National Emissions Inventory (EPA, 2011).- NE_Towns_PopValleys: New England Town polygons (courtesy USGS), with Population in Valleys and Population Density in Valleys calculated by EPA R1 GIS, from 2010 US Census blocks. - VT_E911: Vermont residences (courtesy VT Center for Geographic Information E-911).

  2. Valley photonic crystals for control of spin and topology

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Jian-Wen; Chen, Xiao-Dong; Zhu, Hanyu; Wang, Yuan; Zhang, Xiang

    2016-11-28

    Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing1,2,3,4. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points5,6,7,8,9,10. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials11,12,13,14,15. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley–spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.

  3. Breathing Valley Fever

    Centers for Disease Control (CDC) Podcasts

    2014-02-04

    Dr. Duc Vugia, chief of the Infectious Diseases Branch in the California Department of Public Health, discusses Valley Fever.  Created: 2/4/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/5/2014.

  4. Groundwater-flow and land-subsidence model of Antelope Valley, California

    Science.gov (United States)

    Siade, Adam J.; Nishikawa, Tracy; Rewis, Diane L.; Martin, Peter; Phillips, Steven P.

    2014-01-01

    Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley groundwater basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, groundwater provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most groundwater pumping in the valley occurs in the Antelope Valley groundwater basin, which includes the rapidly growing cities of Lancaster and Palmdale. Groundwater-level declines of more than 270 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may increase reliance on groundwater.

  5. Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field.

    Science.gov (United States)

    Zhao, Chuan; Norden, Tenzin; Zhang, Peiyao; Zhao, Puqin; Cheng, Yingchun; Sun, Fan; Parry, James P; Taheri, Payam; Wang, Jieqiong; Yang, Yihang; Scrace, Thomas; Kang, Kaifei; Yang, Sen; Miao, Guo-Xing; Sabirianov, Renat; Kioseoglou, George; Huang, Wei; Petrou, Athos; Zeng, Hao

    2017-08-01

    Exploiting the valley degree of freedom to store and manipulate information provides a novel paradigm for future electronics. A monolayer transition-metal dichalcogenide (TMDC) with a broken inversion symmetry possesses two degenerate yet inequivalent valleys, which offers unique opportunities for valley control through the helicity of light. Lifting the valley degeneracy by Zeeman splitting has been demonstrated recently, which may enable valley control by a magnetic field. However, the realized valley splitting is modest (∼0.2 meV T -1 ). Here we show greatly enhanced valley spitting in monolayer WSe 2 , utilizing the interfacial magnetic exchange field (MEF) from a ferromagnetic EuS substrate. A valley splitting of 2.5 meV is demonstrated at 1 T by magnetoreflectance measurements and corresponds to an effective exchange field of ∼12 T. Moreover, the splitting follows the magnetization of EuS, a hallmark of the MEF. Utilizing the MEF of a magnetic insulator can induce magnetic order and valley and spin polarization in TMDCs, which may enable valleytronic and quantum-computing applications.

  6. Quaternary glaciation of the Tashkurgan Valley, Southeast Pamir

    Science.gov (United States)

    Owen, Lewis A.; Chen, Jie; Hedrick, Kathyrn A.; Caffee, Marc W.; Robinson, Alexander C.; Schoenbohm, Lindsay M.; Yuan, Zhaode; Li, Wenqiao; Imrecke, Daniel B.; Liu, Jinfeng

    2012-07-01

    The Quaternary glacial history of Tashkurgan valley, in the transition between the Pamir and Karakoram, in Xinjiang Province, China was examined using remote sensing, field mapping, geomorphic analysis of landforms and sediments, and 10Be terrestrial cosmogenic nuclide dating. Moraines were assigned to four glacial stages: 1) the Dabudaer glacial stage that dates to the penultimate glacial cycle and/or earlier, and may represent one or more glaciations; 2) the Tashkurgan glacial stage that dates to early last glacial, most likely Marine Oxygen Isotope Stage (MIS) 4; 3) the Hangdi glacial stage that dates to MIS 2, possibly early MIS 2; and 4) the Kuzigun glacial stage that dates to the MIS 2, possibly the global Last Glacial Maximum, and is younger than the Hangdi glacial stage. Younger moraines and rock glaciers are present at the heads of tributary valleys; but these were inaccessible because they are located close to politically sensitive borders with Pakistan, Afghanistan and Tajikistan. Glaciers during the Dabudaer glacial stage advanced into the central part of the Tashkurgan valley. During the Tashkurgan glacial stages, glaciers advanced several kilometers beyond the mouths of the tributary valleys into the Tashkurgan valley. Glaciers during the Hangdi and Kuzigun glacial stages advanced just beyond the mouths of the tributary valleys. Glaciation in this part of the Himalayan-Tibetan orogen is likely strongly controlled by northern hemisphere climate oscillations, although a monsoonal influence on glaciation cannot be ruled out entirely.

  7. New Mexico Math Pathways Taskforce Report

    Science.gov (United States)

    New Mexico Higher Education Department, 2016

    2016-01-01

    In April 2015 New Mexico faculty, Dana Center staff, and New Mexico Higher Education (NMHED) co-presented the need for better math pathways statewide. Faculty from 6 institutions (New Mexico State University, New Mexico Highlands University, Dine College, Eastern New Mexico University, El Paso Community College, and San Juan College) participated…

  8. Potential hydrologic characterization wells in Amargosa Valley

    International Nuclear Information System (INIS)

    Lyles, B.; Mihevc, T.

    1994-09-01

    More than 500 domestic, agricultural, and monitoring wells were identified in the Amargosa Valley. From this list, 80 wells were identified as potential hydrologic characterization wells, in support of the US Department of Energy (DOE) Underground Test Area/Remedial Investigation and Feasibility Study (UGTA/RIFS). Previous hydrogeologic studies have shown that groundwater flow in the basin is complex and that aquifers may have little lateral continuity. Wells located more than 10 km or so from the Nevada Test Site (NTS) boundary may yield data that are difficult to correlate to sources from the NTS. Also, monitoring well locations should be chosen within the guidelines of a hydrologic conceptual model and monitoring plan. Since these do not exist at this time, recompletion recommendations will be restricted to wells relatively close (approximately 20 km) to the NTS boundary. Recompletion recommendations were made for two abandoned agricultural irrigation wells near the town of Amargosa Valley (previously Lathrop Wells), for two abandoned wildcat oil wells about 10 km southwest of Amargosa Valley, and for Test Well 5 (TW-5), about 10 km east of Amargosa Valley

  9. MX Siting Investigation. Gravity Survey - Sevier Desert Valley, Utah.

    Science.gov (United States)

    1981-01-24

    Cheyenne, Wyoming. DMAHTC reduces the data to Simple Bouguer Anomaly (see Section A1.4, Appendix Al.0). The Defense Mapping Agency Aerospace Center...Desert Valley, Utah ......... 2 2 Topographic Setting - Sevier Desert Valley, Utah . 3 LIST OF DRAWINGS Drawing Number 1 Complete Bouguer Anomaly...gravity stations were distributed throughout the valley at an approxi- mate interval of 1.4 miles (2.3 km). Drawing 1 is a Complete Bouguer Anomaly

  10. English Teaching in Mexico.

    Science.gov (United States)

    Salazar, Denise

    2002-01-01

    Discusses teaching English in Mexico, a country with important social, cultural, and economic ties to the United States. Looks at the various English teaching situations as well as teacher education for teachers in Mexico. Concludes that the English teaching situation in Mexico reflects great diversity and growth, and that the knowledge of English…

  11. Sutter Buttes-the lone volcano in California's Great Valley

    Science.gov (United States)

    Hausback, Brain P.; Muffler, L.J. Patrick; Clynne, Michael A.

    2011-01-01

    The volcanic spires of the Sutter Buttes tower 2,000 feet above the farms and fields of California's Great Valley, just 50 miles north-northwest of Sacramento and 11 miles northwest of Yuba City. The only volcano within the valley, the Buttes consist of a central core of volcanic domes surrounded by a large apron of fragmental volcanic debris. Eruptions at the Sutter Buttes occurred in early Pleistocene time, 1.6 to 1.4 million years ago. The Sutter Buttes are not part of the Cascade Range of volcanoes to the north, but instead are related to the volcanoes in the Coast Ranges to the west in the vicinity of Clear Lake, Napa Valley, and Sonoma Valley.

  12. Gravity and magnetic data of Midway Valley, southwest Nevada

    International Nuclear Information System (INIS)

    Ponce, D.A.; Langenheim, V.E.; Sikora, R.F.

    1993-01-01

    Detailed gravity and ground magnetic data collected along five traverses across Midway Valley on the eastern flank of Yucca Mountain in southwest Nevada are described. These data were collected as part of an effort to evaluate faulting in the vicinity of proposed surface facilities for a potential nuclear waste repository at Yucca Mountain. Geophysical data show that Midway Valley is bounded by large gravity and magnetic anomalies associated with the Bow Ridge and Paintbrush Canyon faults, on the west side of Exile Hill and on the west flank of Fran Ridge, respectively. In addition, Midway Valley itself is characterized by a number of small-amplitude anomalies that probably reflect small-scale faulting beneath Midway Valley

  13. 27 CFR 9.208 - Snake River Valley.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Snake River Valley. 9.208... Snake River Valley. (a) Name. The name of the viticultural area described in this section is “Snake River Valley”. For purposes of part 4 of this chapter, “Snake River Valley” is a term of viticultural...

  14. Subglacial tunnel valleys in the Alpine foreland: an example from Bern, Switzerland

    International Nuclear Information System (INIS)

    Duerst Stucki, M.; Reber, R.; Schlunegger, F.

    2010-01-01

    The morphology of the Alpine and adjacent landscapes is directly related to glacial erosion and associated sediment transport. Here we report the effects of glacio-hydrologic erosion on bedrock topography in the Swiss Plateau. Specifically, we identify the presence of subsurface valleys beneath the city of Bern and discuss their genesis. Stratigraphic investigations of more than 4'000 borehole data within a 430 km 2 -large area reveal the presence of a network of >200 m-deep and 1'000 m-wide valleys. They are flat floored with steep sided walls and are filled by Quaternary glacial deposits. The central valley beneath Bern is straight and oriented towards the NNW, with valley flanks more than 20 o steep. The valley bottom has an irregular undulating profile along the thalweg, with differences between sills and hollows higher than 50-100 m over a reach of 4 km length. Approximately 500 m high bedrock highlands flank the valley network. The highlands are dissected by up to 80 m-deep and 500 m-broad hanging valleys that currently drain away from the axis of the main valley. We interpret the valleys beneath the city of Bern to be a tunnel valley network which originated from subglacial erosion by melt water. The highland valleys served as proglacial meltwater paths and are hanging with respect to the trunk system, indicating that these incipient highland systems as well as the main gorge beneath Bern formed by glacial melt water under pressure. (authors)

  15. Gate-tunable valley-spin filtering in silicene with magnetic barrier

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X. Q., E-mail: xianqiangzhe@126.com [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Meng, H. [School of Physics and Telecommunication Engineering, Shanxi University of Technology, Hanzhong 723001 (China)

    2015-05-28

    We theoretically study the valley- and spin-resolved scattering through magnetic barrier in a one layer thick silicene, using the mode-matching method for the Dirac equation. We show that the spin-valley filtering effect can be achieved and can also be tuned completely through both a top and bottom gate. Moreover, when reversing the sign of the staggered potential, we find the direction of the valley polarization is switched while the direction of spin polarization is unchanged. These results can provide some meaningful information to design valley valve residing on silicene.

  16. VALDRIFT 1.0: A valley atmospheric dispersion model with deposition

    Energy Technology Data Exchange (ETDEWEB)

    Allwine, K.J.; Bian, X.; Whiteman, C.D.

    1995-05-01

    VALDRIFT version 1.0 is an atmospheric transport and diffusion model for use in well-defined mountain valleys. It is designed to determine the extent of ddft from aedal pesticide spraying activities, but can also be applied to estimate the transport and diffusion of various air pollutants in valleys. The model is phenomenological -- that is, the dominant meteorological processes goveming the behavior of the valley atmosphere are formulated explicitly in the model, albeit in a highly parameterized fashion. The key meteorological processes treated are: (1) nonsteady and nonhomogeneous along-valley winds and turbulent diffusivities, (2) convective boundary layer growth, (3) inversion descent, (4) noctumal temperature inversion breakup, and (5) subsidence. The model is applicable under relatively cloud-free, undisturbed synoptic conditions and is configured to operate through one diumal cycle for a single valley. The inputs required are the valley topographical characteristics, pesticide release rate as a function of time and space, along-valley wind speed as a function of time and space, temperature inversion characteristics at sunrise, and sensible heat flux as a function of time following sunrise. Default values are provided for certain inputs in the absence of detailed observations. The outputs are three-dimensional air concentration and ground-level deposition fields as a function of time.

  17. Valley-selective optical Stark effect probed by Kerr rotation

    Science.gov (United States)

    LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.

    2018-01-01

    The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.

  18. Geologic map of the Sunshine 7.5' quadrangle, Taos County, New Mexico

    Science.gov (United States)

    Thompson, Ren A.; Turner, Kenzie J.; Shroba, Ralph R.; Cosca, Michael A.; Ruleman, Chester A.; Lee, John P.; Brandt, Theodore R.

    2014-01-01

    The Sunshine 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Sunshine Valley, named for the small locale of Sunshine, is incised by a series of northeast-trending drainages cut into Tertiary and Quaternary alluvial deposits forming an extensive alluvial apron between the east flank of the Sangre de Cristo Mountains and the Rio Grande. These deposits predominantly overlie gently eastward-dipping lava flows of Pliocene Servilleta Basalt erupted from centers west of the map area. Servilleta Basalt lava flows terminate to the south against the elevated topography of three volcanic centers of the Taos Plateau volcanic field. From west to east these are Cerro de la Olla, Cerro Chiflo, and Guadalupe Mountain that are exposed in the southern part of the map area. Remnants of Miocene volcanic rocks are exposed near the southwestern edge of the map area and record evidence of an eroded volcanic terrain underlying deposits of the Taos Plateau volcanic field. These deposits are likely fault bounded to the east, roughly coincident with north to northwest trending, down-to-east faults in the southwestern quarter of the map area. The down-to-east normal faults reflect the basinward migration of the western margin of the Sunshine Valley sub-basin of the southern San Luis Basin.

  19. Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

    Science.gov (United States)

    Demopoulos, Amanda W.J.; Gualtieri, Daniel; Kovacs, Kaitlin

    2010-01-01

    The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal delta13C and delta15N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light delta15N and delta13C values, indicating possible reliance on chemoautotrophic symbioses. The lightest delta13C and delta15N values were observed in nematodes (delta13C=-54.6 + or - 0.1 per mil, delta15N=-6.1 + or - 0.2 per mil) and one gastropod (delta13C=-54.1 per mil, delta15N=-1.1 per mil) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.

  20. New Mexico Parks

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the locations of parks in New Mexico, in point form, with limited attributes, compiled using available data from a...

  1. Four newly recorded species of Dryopteridaceae from Kashmir valley, India

    Directory of Open Access Journals (Sweden)

    SHAKOOR AHMAD MIR

    2014-04-01

    Full Text Available Mir SA, Mishra AK, Reshi ZA, Sharma MP. 2014. Four newly recorded species of Dryopteridaceae from Kashmir valley, India. Biodiversitas 15: 6-11. Habitat diversity, elevation, cloud cover, rainfall, seasonal and temperature variations have created many ideal sites for the luxuriant growth of pteridophytes in the Kashmir valley, yet all the regions of the valley have not been surveyed. In Kashmir valley the family Dryopteridaceae is represented by 31 species. During the recent extensive field surveys of Shopian district four more species viz., Dryopteris caroli-hopei Fraser-Jenkins, Dryopteris blanfordii subsp. nigrosquamosa (Ching Fraser-Jenkins, Dryopteris pulvinulifera (Bedd. Kuntze and Polystichum Nepalense (Spreng C. Chr. have been recorded for the first time from the valley. The taxonomic description, synonyms, distribution and photographs of each species are given in this article.

  2. Serologic survey for selected arboviruses and other potential pathogens in wildlife from Mexico.

    Science.gov (United States)

    Aguirre, A A; McLean, R G; Cook, R S; Quan, T J

    1992-07-01

    During 1988 and 1989, a serologic survey of wildlife was conducted in northeastern Mexico to determine the presence, prevalence, and distribution of arboviruses and other selected disease agents. Eighty mammal specimens were tested. Antibodies to vesicular stomatitis-Indiana, Venezuelan equine encephalitis-Mena II, Rio Grande virus, and vesicular stomatitis-New Jersey were detected predominantly in small mammals. Deer and mouflon (Ovis musimon) had antibodies to bluetongue and epizootic hemorrhagic disease. Two species had serologic evidence of recent exposure to Francisella tularensis. A white-tailed deer (Odocoileus virginianus) had antibodies to Anaplasma marginale. All specimens tested for antibodies against Yersinia pestis and Brucella abortus were negative. Sera from 315 birds were tested for antibody against five equine encephalitis viruses and six avian pathogens. During 1988, antibodies to Venezuelan equine encephalitis-Mena II, Venezuelan equine encephalitis-TC83, St. Louis encephalitis, eastern equine encephalitis, and western equine encephalitis were detected in birds of several species. Antibodies to Pasteurella multocida and Newcastle disease virus were also detected. Birds from five species presented antibodies to Mycoplasma meleagridis. Specimens tested for M. gallisepticum, M. synoviae, and Chlamydia psittaci were negative. To the best of our knowledge, this survey represents the first serologic evidence of bluetongue, Cache Valley virus, epizootic hemorrhagic disease, Jamestown Canyon virus, vesicular stomatitis-Indiana, vesicular stomatitis-New Jersey, Rio Grande virus, and tularemia reported among wildlife in Mexico.

  3. Semiarid ethnoagroforestry management: Tajos in the Sierra Gorda, Guanajuato, Mexico.

    Science.gov (United States)

    Hoogesteger van Dijk, Vincent M; Casas, Alejandro; Moreno-Calles, Ana Isabel

    2017-06-12

    The semi-arid environments harbor nearly 40% of biodiversity, and half of indigenous cultures of Mexico. Thousands of communities settled in these areas depend on agriculture and using wild biodiversity for their subsistence. Water, soil, and biodiversity management strategies are therefore crucial for people's life. The tajos, from Sierra Gorda, are important, poorly studied, biocultural systems established in narrow, arid alluvial valleys. The systems are constructed with stone-walls for capturing sediments, gradually creating fertile soils in terraces suitable for agriculture in places where it would not be possible. We analyzed biocultural, ecological, economic and technological relevance of the artificial oasis-like tajos, hypothesizing their high capacity for maintaining agricultural and wild biodiversity while providing resources to people. We conducted our research in three sections of the Mezquital-Xichú River, in three communities of Guanajuato, Mexico. Agroforestry management practices were documented through semi-structured and in-depth qualitative interviews. Vegetation composition of local forests and that maintained in tajos was sampled and compared. Tajos harbor high agrobiodiversity, including native varieties of maize and beans, seven secondary crops, 47 native and 25 introduced perennial plant species. Perennial plants cover on average 26.8% of the total surface of plots. Tajos provide nearly 70% of the products required by households' subsistence and are part of their cultural identity. Tajos are heritage of TEK and land management forms of pre-Columbian Mexican and Mediterranean agricultural techniques, adapting and integrating modern agricultural practices. Tajos are valuable biocultural systems adapted to local semiarid conditions and sources of technology for similar areas of the World.

  4. Fitness-valley crossing with generalized parent-offspring transmission.

    Science.gov (United States)

    Osmond, Matthew M; Otto, Sarah P

    2015-11-01

    Simple and ubiquitous gene interactions create rugged fitness landscapes composed of coadapted gene complexes separated by "valleys" of low fitness. Crossing such fitness valleys allows a population to escape suboptimal local fitness peaks to become better adapted. This is the premise of Sewall Wright's shifting balance process. Here we generalize the theory of fitness-valley crossing in the two-locus, bi-allelic case by allowing bias in parent-offspring transmission. This generalization extends the existing mathematical framework to genetic systems with segregation distortion and uniparental inheritance. Our results are also flexible enough to provide insight into shifts between alternate stable states in cultural systems with "transmission valleys". Using a semi-deterministic analysis and a stochastic diffusion approximation, we focus on the limiting step in valley crossing: the first appearance of the genotype on the new fitness peak whose lineage will eventually fix. We then apply our results to specific cases of segregation distortion, uniparental inheritance, and cultural transmission. Segregation distortion favouring mutant alleles facilitates crossing most when recombination and mutation are rare, i.e., scenarios where crossing is otherwise unlikely. Interactions with more mutable genes (e.g., uniparental inherited cytoplasmic elements) substantially reduce crossing times. Despite component traits being passed on poorly in the previous cultural background, small advantages in the transmission of a new combination of cultural traits can greatly facilitate a cultural transition. While peak shifts are unlikely under many of the common assumptions of population genetic theory, relaxing some of these assumptions can promote fitness-valley crossing. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Subglacial tunnel valleys in the Alpine foreland: an example from Bern, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Duerst Stucki, M.; Reber, R.; Schlunegger, F.

    2010-12-15

    The morphology of the Alpine and adjacent landscapes is directly related to glacial erosion and associated sediment transport. Here we report the effects of glacio-hydrologic erosion on bedrock topography in the Swiss Plateau. Specifically, we identify the presence of subsurface valleys beneath the city of Bern and discuss their genesis. Stratigraphic investigations of more than 4'000 borehole data within a 430 km{sup 2}-large area reveal the presence of a network of >200 m-deep and 1'000 m-wide valleys. They are flat floored with steep sided walls and are filled by Quaternary glacial deposits. The central valley beneath Bern is straight and oriented towards the NNW, with valley flanks more than 20 {sup o} steep. The valley bottom has an irregular undulating profile along the thalweg, with differences between sills and hollows higher than 50-100 m over a reach of 4 km length. Approximately 500 m high bedrock highlands flank the valley network. The highlands are dissected by up to 80 m-deep and 500 m-broad hanging valleys that currently drain away from the axis of the main valley. We interpret the valleys beneath the city of Bern to be a tunnel valley network which originated from subglacial erosion by melt water. The highland valleys served as proglacial meltwater paths and are hanging with respect to the trunk system, indicating that these incipient highland systems as well as the main gorge beneath Bern formed by glacial melt water under pressure. (authors)

  6. Ozone Laminae and Their Entrainment Into a Valley Boundary Layer, as Observed From a Mountaintop Monitoring Station, Ozonesondes, and Aircraft Over California's San Joaquin Valley

    Science.gov (United States)

    Faloona, I. C.; Conley, S. A.; Caputi, D.; Trousdell, J.; Chiao, S.; Eiserloh, A. J., Jr.; Clark, J.; Iraci, L. T.; Yates, E. L.; Marrero, J. E.; Ryoo, J. M.; McNamara, M. E.

    2016-12-01

    The San Joaquin Valley of California is wide ( 75 km) and long ( 400 km), and is situated under strong atmospheric subsidence due, in part, to the proximity of the midlatitude anticyclone of the Pacific High. The capping effect of this subsidence is especially prominent during the warm season when ground level ozone is a serious air quality concern across the region. While relatively clean marine boundary layer air is primarily funneled into the valley below the strong subsidence inversion at significant gaps in the upwind Coast Range mountains, airflow aloft also spills over these barriers and mixes into the valley from above. Because this transmountain flow occurs under the influence of synoptic subsidence it tends to present discrete, laminar sheets of differing air composition above the valley boundary layer. Meanwhile, although the boundary layers tend to remain shallow due to the prevailing subsidence, orographic and anabatic venting of valley boundary layer air around the basin whips up a complex admixture of regional air masses into a "buffer layer" just above the boundary layer (zi) and below the lower free troposphere. We present scalar data of widely varying lifetimes including ozone, methane, NOx, and thermodynamic observations from upwind and within the San Joaquin Valley to better explain this layering and its subsequent erosion into the valley boundary layer via entrainment. Data collected at a mountaintop monitoring station on Chews Ridge in the Coast Range, by coastal ozonesondes, and aircraft are analyzed to document the dynamic layering processes around the complex terrain surrounding the valley. Particular emphasis will be made on observational methods whereby distal ozone can be distinguished from the regional ozone to better understand the influence of exogenous sources on air quality in the valley.

  7. Geomorphological hazards in Swat valley, Pakistan

    International Nuclear Information System (INIS)

    Usman, A.

    1999-01-01

    This study attempts to describe, interpret and analyze, in depth, the varied geomorphological hazards and their impacts prevailing in the swat valley locate in the northern hilly and mountainous regions of Pakistan. The hills and mountains re zones of high geomorphological activity with rapid rates of weathering, active tectonic activities, abundant precipitation, rapid runoff and heavy sediment transport. Due to the varied topography, lithology, steep slope, erodible soil, heavy winter snowfall and intensive rainfall in the spring and summer seasons, several kinds of geomorphological hazards, such as geomorphic gravitational hazards, Fluvial hazards, Glacial hazards, Geo tectonic hazards, are occurring frequently in swat valley. Amongst them, geomorphic gravitational hazards, such as rock fall rock slide, debris slide mud flow avalanches, are major hazards in mountains and hills while fluvial hazards and sedimentation are mainly confined to the alluvial plain and lowlands of the valley. The Getechtonic hazards, on the other hand, have wide spread distribution in the valley the magnitude and occurrence of each king of hazard is thus, varied according to intensity of process and physical geographic environment. This paper discusses the type distribution and damage due to the various geomorphological hazards and their reduction treatments. The study would to be of particular importance and interest to both natural and social scientists, as well as planner, environmentalists and decision-makers for successful developmental interventions in the region. (author)

  8. Radon availability in New Mexico

    International Nuclear Information System (INIS)

    McLemore, V.T.

    1995-01-01

    The New Mexico Bureau of Mines and Mineral Resources (NMBMMR) in cooperation with the Radiation Licensing and Registration Section of the New Mexico Environment Department (NMED) and the US Environmental Protection Agency (EPA) have been evaluating geologic and soil conditions that may contribute to elevated levels of indoor radon throughout New Mexico. Various data have been integrated and interpreted in order to determine areas of high radon availability. The purpose of this paper is to summarize some of these data for New Mexico and to discuss geologic controls on the distribution of radon. Areas in New Mexico have been identified from these data as having a high radon availability. It is not the intent of this report to alarm the public, but to provide data on the distribution of radon throughout New Mexico

  9. Hybrid spin and valley quantum computing with singlet-triplet qubits.

    Science.gov (United States)

    Rohling, Niklas; Russ, Maximilian; Burkard, Guido

    2014-10-24

    The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over the valley state opens new possibilities for quantum information processing. Combining qubits encoded in the singlet-triplet subspace of spin and valley states allows for universal QC using a universal two-qubit gate directly provided by the exchange interaction. We show how spin and valley qubits can be separated in order to allow for single-qubit rotations.

  10. A physical model of the Mexico City seismic response after the damaging M7.1 earthquake of September 19, 2017

    Science.gov (United States)

    Cruz-Atienza, V. M.; Tago, J.; Villafuerte, C. D.; Chaljub, E.; Sanabria-Gómez, J. D.

    2017-12-01

    Built-up on top of ancient lake deposits, Mexico City experiences some of the largest seismic site effects in the world. The M7.1 intermediate-depth earthquake of September 19, 2017 (S19) collapsed 43 one-to-ten story buildings in the city close to the western edge of the lake-bed sediments, on top of the geotechnically-known transition zone. In this work we explore the physical reasons explaining such a damaging pattern and the long-lasting strong motion records well-documented from past events by means of new observations and high performance computational modeling. Besides the extreme amplification of seismic waves, duration of intense ground motion in the lake-bed lasts more than three times those recorded in hard-rock a few kilometers away. Different mechanisms contribute to the long lasting motions, such as the regional dispersion and multiple-scattering of the incoming wavefield all the way from the source. However, recent beamforming observations at hard-rock suggest that duration of the incoming field is significantly shorter than the strong shaking in the lake-bed. We show that despite the highly dissipative shallow deposits, seismic energy can propagate long distances in the deep structure of the valley, promoting also a large elongation of motion. Our simulations reveal that the seismic response of the basin is dominated by surface-waves overtones, and that this mechanism increases the duration of ground motion up to 280% and 500% of the incoming wavefield duration at 0.5 and 0.3 Hz, respectively. Furthermore, our results indicate that the damage pattern of the S19 earthquake is most likely due to the propagation of the fundamental mode in the transition zone of the basin. These conclusions contradicts what has been previously stated from observational and modeling investigations, where the basin itself has been discarded as a preponderant factor promoting long and devastating shaking in Mexico City. Reference: Cruz-Atienza, V. M., J. Tago, J. D

  11. Mexico's nuclear paradox

    International Nuclear Information System (INIS)

    Redclift, M.

    1989-01-01

    Opposition to Mexico's nuclear reactors at Laguna Verde has grown during the last two years. The nuclear programme is blamed for being expensive and wasteful, and the decision to rely on the USA contradicts Mexico's espoused policy of greater independence from the USA. The way in which petroleum revenues were used to precipitate the nuclear option is compared with the lack of urgency given to renewable energy and greater energy efficiency. From a social and environmental perspective, as well as an economic one, Mexico's nuclear programme is judged expensive and irrelevant. (author)

  12. Graphene valley pseudospin filter using an extended line defect

    Science.gov (United States)

    Gunlycke, Daniel; White, Carter

    2011-03-01

    Although graphene exhibits excellent electron and thermal transport properties, it does not have an intrinsic band gap, required to use graphene as a replacement material for silicon and other semiconductors in conventional electronics. The band structure of graphene with its two cones near the Fermi level, however, offers opportunities to develop non-traditional applications. One such avenue is to exploit the valley degeneracy in graphene to develop valleytronics. A central component in valleytronics is the valley filter, just as the spin filter is central in spintronics. Herein, we present a two-dimensional valley filter based on scattering of electrons and holes off a recently observed extended line defect [Nat. Nanotech.5, 326 (2010)] within graphene. The transmission probability depends strongly on the valley pseudospin and the angle of incidence of the incident quasiparticles. Quasiparticles arriving at the line defect at a high angle of incidence lead to a valley polarization of the transmitted beam that is near 100 percent. This work was supported by ONR, directly and through NRL.

  13. Hydrological responses to channelization and the formation of valley plugs and shoals

    Science.gov (United States)

    Pierce, Aaron R.; King, Sammy L.

    2017-01-01

    Rehabilitation of floodplain systems focuses on restoring interactions between the fluvial system and floodplain, however, there is a paucity of information on the effects of valley plugs and shoals on floodplain hydrological processes. We investigated hydrologic regimes in floodplains at three valley plug sites, two shoal sites, and three unchannelized sites. Valley plug sites had altered surface and sub-surface hydrology relative to unchannelized sites, while only sub-surface hydrology was affected at shoal sites. Some of the changes were unexpected, such as reduced flood duration and flood depth in floodplains associated with valley plugs. Our results emphasize the variability associated with hydrologic processes around valley plugs and our rudimentary understanding of the effects associated with these geomorphic features. Water table levels were lower at valley plug sites compared to unchannelized sites, however, valley plug sites had a greater proportion of days when water table inundation was above mean root collar depth than both shoal and unchannelized sites as a result of lower root collar depths and higher deposition rates. This study has provided evidence that valley plugs can affect both surface and sub-surface hydrology in different ways than previously thought and illustrates the variability in hydrological responses to valley plug formation.

  14. The California Valley grassland

    Science.gov (United States)

    Keeley, J.E.; Schoenherr, Allan A.

    1990-01-01

    Grasslands are distributed throughout California from Oregon to Baja California Norte and from the coast to the desert (Brown 1982) (Figure 1). This review will focus on the dominant formation in cismontane California, a community referred to as Valley Grassland (Munz 1959). Today, Valley Grassland is dominated by non-native annual grasses in genera such as Avena (wild oat), Bromus (brome grass), and Hordeum (barley), and is often referred to as the California annual grassland. On localized sites, native perennial bunchgrasses such as Stipa pultra (purple needle grass) may dominate and such sites are interpreted to be remnants of the pristine valley grassland. In northwestern California a floristically distinct formation of the Valley Grassland, known as Coast Prairie (Munz 1959) or Northern Coastal Grassland (Holland and Keil 1989) is recognized. The dominant grasses include many native perennial bunchgrasses in genera such as Agrostis, Calamagrostis, Danthonia, Deschampsia, Festuca, Koeleria and Poa (Heady et al. 1977). Non-native annuals do not dominate, but on some sites non-native perennials like Anthoxanthum odoratum may colonize the native grassland (Foin and Hektner 1986). Elevationally, California's grasslands extend from sea level to at leas 1500 m. The upper boundary is vague because montane grassland formations are commonly referred to as meadows; a community which Munz (1959) does not recognize. Holland and Keil (1989) describe the montane meadow as an azonal community; that is, a community restricted not so much to a particular climatic zone but rather controlled by substrate characteristics. They consider poor soil-drainage an over-riding factor in the development of montane meadows and, in contrast to grasslands, meadows often remain green through the summer drought. Floristically, meadows are composed of graminoids; Cyperaceae, Juncaceae, and rhizomatous grasses such as Agropyron (wheat grass). Some bunchgrasses, such as Muhlenbergia rigens, are

  15. Application of water quality index to evaluate groundwater quality (temporal and spatial variation) of an intensively exploited aquifer (Puebla valley, Mexico).

    Science.gov (United States)

    Salcedo-Sánchez, Edith R; Garrido Hoyos, Sofía E; Esteller Alberich, Ma Vicenta; Martínez Morales, Manuel

    2016-10-01

    The spatial and temporal variation of water quality in the urban area of the Puebla Valley aquifer was evaluated using historical and present data obtained during this investigation. The current study assessed water quality based on the Water Quality Index developed by the Canadian Council of Ministers of the Environment (CCME-WQI), which provides a mathematical framework to evaluate the quality of water in combination with a set of conditions representing quality criteria, or limits. This index is flexible regarding the type and number of variables used by the evaluation given that the variables of interest are selected according to the characteristics and objectives of development, conservation and compliance with regulations. The CCME-WQI was calculated using several variables that assess the main use of the wells in the urban area that is public supply, according to criteria for human use and consumption established by Mexican law and international standards proposed by the World Health Organization. The assessment of the index shows a gradual deterioration in the quality of the aquifer over time, as the amount of wells with excellent quality have decreased and those with lower index values (poor quality) have increased throughout the urban area of the Puebla Valley aquifer. The parameters affecting groundwater quality are: total dissolved solids, sulfate, calcium, magnesium and total hardness.

  16. Groundwater quality in the Antelope Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic

  17. Mexico: Rasgos de Su Historia. (Mexico: Highlights of Its History).

    Science.gov (United States)

    Orozco, Cecilio

    Intended for both teachers and students, this publication, written in Spanish, briefly traces Mexico's history from its Conquest in 1519 to the overthrow of Porfirio Diaz in 1910. The following are briefly discussed: Mexico's Conquest in 1519; events immediately after the fall of Tenochtitlan; the War for Independence; Texas' separation from…

  18. The Health Valley: Global Entrepreneurial Dynamics.

    Science.gov (United States)

    Dubuis, Benoit

    2014-12-01

    In the space of a decade, the Lake Geneva region has become the Health Valley, a world-class laboratory for discovering and developing healthcare of the future. Through visionary individuals and thanks to exceptional infrastructure this region has become one of the most dynamic in the field of innovation, including leading scientific research and exceptional actors for the commercialization of academic innovation to industrial applications that will improve the lives of patients and their families. Here follows the chronicle of a spectacular expansion into the Health Valley.

  19. Solar energy innovation and Silicon Valley

    Science.gov (United States)

    Kammen, Daniel M.

    2015-03-01

    The growth of the U. S. and global solar energy industry depends on a strong relationship between science and engineering innovation, manufacturing, and cycles of policy design and advancement. The mixture of the academic and industrial engine of innovation that is Silicon Valley, and the strong suite of environmental policies for which California is a leader work together to both drive the solar energy industry, and keep Silicon Valley competitive as China, Europe and other area of solar energy strength continue to build their clean energy sectors.

  20. 78 FR 14983 - Fisheries of the Gulf of Mexico; Gulf of Mexico Fishery Management Council; Public Meeting

    Science.gov (United States)

    2013-03-08

    ... the Gulf of Mexico; Gulf of Mexico Fishery Management Council; Public Meeting AGENCY: National Marine... of Gulf of Mexico Fishery Management Council Spanish Mackerel and Cobia Stock Assessment Review Workshop. SUMMARY: Independent peer review of Gulf of Mexico Spanish Mackerel and Cobia stocks will be...

  1. Coyotes, Concessions and Construction Companies: Illegal Water Markets and Legally Constructed Water Scarcity in Central Mexico

    Directory of Open Access Journals (Sweden)

    Nadine Reis

    2014-10-01

    Full Text Available Many regions of (semiarid Mexico, such as the Valley of Toluca, face challenges due to rapid growth and the simultaneous overexploitation of groundwater. The water reform of the 1990s introduced individual water rights concessions granted through the National Water Commission (Comisión Nacional del Agua, or CONAGUA. Since then, acquiring new water rights in officially 'water-scarce' aquifers is only possible through official rights transmissions from users ceding their rights. With the law prohibiting the sale of water rights, a profitable illegal market for these rights has emerged. The key actor in the water rights allocation network is the coyote, functioning as a broker between a people wanting to cede water rights and those needing them, and b the formal and informal spheres of water rights allocation. Actors benefitting from water rights trading include the coyote and his 'working brigades', water users selling surplus rights, and (senior and lower-level staff in the water bureaucracy. The paper concludes that legally constructed water scarcity is key to the reproduction of illegal water rights trading. This has important implications regarding the current push for expanding regularisation of groundwater extraction in Mexico. Currently, regularisation does not counter overexploitation, while possibly leading to a de facto privatisation of groundwater.

  2. Binational Teacher Development: Teacher Ambassador Exchange Program, New Mexico, USA and Nuevo Leon, Mexico.

    Science.gov (United States)

    Habermann, Mary Jean

    The report describes the rationale for and history of an exchange program for Nuevo Leon (Mexico) and New Mexico bilingual education teachers. The program evolved from the need to help Spanish-speaking students maintain their own language and culture while in the United States. New Mexico's state policy concerning language-minority children and…

  3. Biogeochemical studies of wintering waterfowl in the Imperial and Sacramento Valleys

    Energy Technology Data Exchange (ETDEWEB)

    Koranda, J.J.; Stuart, M.; Thompson, S.; Conrado, C.

    1979-10-01

    Trace and major elemental composition were determined in the organs of wintering waterfowl in the Imperial and Sacramento Valleys of California, and in soils, sediments, and agricultural fertilizer that constitute the various sources of elements in the waterfowl. These data provide a biogeochemical baseline for waterfowl populations wintering in an area being developed for geothermal power. This baseline in the Imperial Valley is affected by soil and sediment composition, agricultural effluents in irrigation and stream water, and spent shot deposited by hunters in waterfowl habitats. The waterfowl acquire a set of trace elements from these sources and concentrations increase in their organs over the wintering period. Nickel, arsenic, selenium, bromine, and lead are the primary elements acquired from soil sources, agricultural effluents, and spent shot in the Imperial Valley. The assessment of effects from geothermal effluents on waterfowl populations in complex because there are large influxes of materials into the Imperial Valley ecosystem that contain trace elements, i.e., irrigation water, phosphatic fertilizers, pesticides, and lead shot. Multiple sources exist for many elements prominent in the expected geothermal effluents. The relationships between the two California valleys, the Imperial and Sacramento, are apparent in the trace element concentrations in the organs of waterfowl obtained in those two valleys. Arsenic is absent in the waterfowl organs obtained in the Sacramento Valley and relatively common in the Imperial Valley waterfowl. The effect of any release of geothermal effluent in the Imperial Valley waterfowl habitats will be difficult to describe because of the complexity of the biogeochemical baseline and the multiple sources of trace and major elements in the ecosystem.

  4. Goldstone-Apple Valley Radio Telescope System Theory of Operation

    Science.gov (United States)

    Stephan, George R.

    1997-01-01

    The purpose of this learning module is to enable learners to describe how the Goldstone-Apple Valley Radio Telescope (GAVRT) system functions in support of Apple Valley Science and Technology Center's (AVSTC) client schools' radio astronomy activities.

  5. Floristic affinities of the lowland savannahs of Belize and southern Mexico.

    Science.gov (United States)

    Canché-Estrada, Idalia Arely; Ortiz-Díaz, Juan Javier; Tun-Garrido, Juan

    2018-01-01

    Environmental heterogeneity of Belize and southern Mexico savannahs as well as their geographical location suggest that these plant communities share floristic elements, making them conducive to a phytogeographical analysis. The aim of this study was to analyse the floristic affinities of nine savannahs of Belize and southern Mexico and to explain the similarities and differences amongst them. A binary data matrix containing 915 species was built based on the authors' own collections and on nine floristic lists already published. A second data matrix, consisting of 113 species representing trees, was also used since most literature on neotropical savannahs has focused on this life form. In addition, the ten most species-rich families as well as the characteristic species present in more than five savannahs were analysed. Floristic similarities were calculated using the Jaccard index. Dendrograms obtained in both types of analysis showed clusters with low similarity values, corresponding to geographic locations formed by the savannahs of Belize-Tabasco and the Yucatan Peninsula. The floristic affinities of the savannahs may be explained in terms of heterogeneity in climate and physiography. The Yucatan Peninsula and Belize-Tabasco groups have differences in climate type and the amount of rainfall. In addition, the Yucatan Peninsula savannahs are established at the bottom of karstic valleys, while the Belize and Tabasco savannahs develop on extensive flatlands. The savannahs of Oaxaca have the same climate type and amount of rainfall as those of the Yucatan Peninsula but they are distributed along peaks and the slopes of shale hills. Fabaceae and Poaceae mainly dominated the local floras with 121 and 116 species each; remarkably, Melastomataceae was absent in the Yucatan Peninsula and Oaxaca. Nine species occurred in five to seven savannahs, confirming that they are widespread in both Belize and southern Mexico, and the Neotropics. Geographic location and floristic

  6. Summary of the engineering assessment of inactive uranium mill tailings: Monument Valley site, Monument Valley, Arizona

    International Nuclear Information System (INIS)

    1981-10-01

    Ford, Bacon and Davis Utah Inc. has reevaluated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material to removal of the tailings to remote disposal sites and decontamination of the tailings site. Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching, treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be more than $500/lb of U 3 O 8 by heap leach or conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is economically unattractive

  7. Topographic evolution of Yosemite Valley from Low Temperature Thermochronology

    Science.gov (United States)

    Tripathy-Lang, A.; Shuster, D. L.; Cuffey, K. M.; Fox, M.

    2014-12-01

    In this contribution, we interrogate the timing of km-scale topography development in the region around Yosemite Valley, California. Our goal is to determine when this spectacular glacial valley was carved, and how this might help address controversy surrounding the topographic evolution of the Sierra Nevada. At the scale of the range, two rival hypotheses are each supported by different datasets. Low-temperature thermochronology supports the idea that the range has been high-standing since the Cretaceous, whereas geomorphic evidence suggests that much of the elevation of the Sierra Nevada was attained during the Pliocene. Recent work by McPhillips and Brandon (2012) suggests instead that both ideas are valid, with the range losing much elevation during the Cenozoic, but regaining it during Miocene surface uplift.At the local scale, the classic study of Matthes (1930) determined that most of Yosemite Valley was excavated by the Sherwin-age glaciation that ended ~1 Ma. The consensus view is in agreement, although some argue that nearby comparable valleys comparable were carved long ago (e.g., House et al., 1998). If the Quaternary and younger glaciations were responsible for the bulk of the valley's >1 km depth, we might expect apatite (U-Th)/He ages at the valley floor to be histories at these locations, these data constrain patterns of valley topography development through time. We also supplement these data with zircon 4He/3He thermochronometry, which is a newly developed method that provides information on continuous cooling paths through ~120-220 °C. We will present both the apatite and zircon 4He/3He data and, in conjunction with thermo-kinematic modeling, discuss the ability and limitations of these data to test models of Sierra Nevada topography development through time. Matthes (1930) USGS Professional Paper House et al. (1998) Nature McPhillips and Brandon (2012) American Journal of Science

  8. Optimal decentralized valley-filling charging strategy for electric vehicles

    International Nuclear Information System (INIS)

    Zhang, Kangkang; Xu, Liangfei; Ouyang, Minggao; Wang, Hewu; Lu, Languang; Li, Jianqiu; Li, Zhe

    2014-01-01

    Highlights: • An implementable charging strategy is developed for electric vehicles connected to a grid. • A two-dimensional pricing scheme is proposed to coordinate charging behaviors. • The strategy effectively works in decentralized way but achieves the systematic valley filling. • The strategy allows device-level charging autonomy, and does not require a bidirectional communication/control network. • The strategy can self-correct when confronted with adverse factors. - Abstract: Uncoordinated charging load of electric vehicles (EVs) increases the peak load of the power grid, thereby increasing the cost of electricity generation. The valley-filling charging scenario offers a cheaper alternative. This study proposes a novel decentralized valley-filling charging strategy, in which a day-ahead pricing scheme is designed by solving a minimum-cost optimization problem. The pricing scheme can be broadcasted to EV owners, and the individual charging behaviors can be indirectly coordinated. EV owners respond to the pricing scheme by autonomously optimizing their individual charge patterns. This device-level response induces a valley-filling effect in the grid at the system level. The proposed strategy offers three advantages: coordination (by the valley-filling effect), practicality (no requirement for a bidirectional communication/control network between the grid and EV owners), and autonomy (user control of EV charge patterns). The proposed strategy is validated in simulations of typical scenarios in Beijing, China. According to the results, the strategy (1) effectively achieves the valley-filling charging effect at 28% less generation cost than the uncoordinated charging strategy, (2) is robust to several potential affecters of the valley-filling effect, such as (system-level) inaccurate parameter estimation and (device-level) response capability and willingness (which cause less than 2% deviation in the minimal generation cost), and (3) is compatible with

  9. Mexico Wind Resource Assessment Project

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, M.N.; Elliott, D.L.

    1995-05-01

    A preliminary wind energy resource assessment of Mexico that produced wind resource maps for both utility-scale and rural applications was undertaken as part of the Mexico-U.S. Renewable Energy Cooperation Program. This activity has provided valuable information needed to facilitate the commercialization of small wind turbines and windfarms in Mexico and to lay the groundwork for subsequent wind resource activities. A surface meteorological data set of hourly data in digital form was utilized to prepare a more detailed and accurate wind resource assessment of Mexico than otherwise would have been possible. Software was developed to perform the first ever detailed analysis of the wind characteristics data for over 150 stations in Mexico. The hourly data set was augmented with information from weather balloons (upper-air data), ship wind data from coastal areas, and summarized wind data from sources in Mexico. The various data were carefully evaluated for their usefulness in preparing the wind resource assessment. The preliminary assessment has identified many areas of good-to-excellent wind resource potential and shows that the wind resource in Mexico is considerably greater than shown in previous surveys.

  10. Late oligocene and miocene faulting and sedimentation, and evolution of the southern Rio Grande rift, New Mexico, USA

    Science.gov (United States)

    Mack, Greg H.; Seager, William R.; Kieling, John

    1994-08-01

    The distribution of nonmarine lithofacies, paleocurrents, and provenance data are used to define the evolution of late Oligocene and Miocene basins and complementary uplifts in the southern Rio Grande rift in the vicinity of Hatch, New Mexico, USA. The late Oligocene-middle Miocene Hayner Ranch Formation, which consists of a maximum of 1000 m of alluvial-fan, alluvial-flat, and lacustrine-carbonate lithofacies, was deposited in a narrow (12 km), northwest-trending, northeast-tilted half graben, whose footwall was the Caballo Mountains block. Stratigraphic separation on the border faults of the Caballo Mountains block was approximately 1615 m. An additional 854 m of stratigraphic separation along the Caballo Mountains border faults occurred during deposition of the middle-late Miocene Rincon Valley Formation, which is composed of up to 610 m of alluvial-fan, alluvial-flat, braided-fluvial, and gypsiferous playa lithofacies. Two new, north-trending fault blocks (Sierra de las Uvas and Dona Ana Mountains) and complementary west-northwest-tilted half graben also developed during Rincon Valley time, with approximately 549 m of stratigraphic separation along the border fault of the Sierra de las Uvas block. In latest Miocene and early Pliocene time, following deposition of the Rincon Valley Formation, movement continued along the border faults of the Caballo Mountains, Dona Ana Mountains, and Sierra de las Uvas blocks, and large parts of the Hayner Ranch and Rincon Valley basins were segmented into smaller fault blocks and basins by movement along new, largely north-trending faults. Analysis of the Hayner Ranch and Rincon Valley Formations, along with previous studies of the early Oligocene Bell Top Formation and late Pliocene-early Pleistocene Camp Rice Formation, indicate that the traditional two-stage model for development of the southern Rio Grande rift should be abandoned in favor of at least four episodes of block faulting beginning 35 Ma ago. With the exception of

  11. Geothermal resource assessment of western San Luis Valley, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Zacharakis, Ted G.; Pearl, Richard Howard; Ringrose, Charles D.

    1983-01-01

    The Colorado Geological Survey initiated and carried out a fully integrated assessment program of the geothermal resource potential of the western San Luis Valley during 1979 and 1980. The San Luis Valley is a large intermontane basin located in southcentral Colorado. While thermal springs and wells are found throughout the Valley, the only thermal waters found along the western part of the Valley are found at Shaw Warm Springs which is a relatively unused spring located approximately 6 miles (9.66 km) north of Del Norte, Colorado. The waters at Shaws Warm Spring have a temperature of 86 F (30 C), a discharge of 40 gallons per minute and contain approximately 408 mg/l of total dissolved solids. The assessment program carried out din the western San Luis Valley consisted of: soil mercury geochemical surveys; geothermal gradient drilling; and dipole-dipole electrical resistivity traverses, Schlumberger soundings, Audio-magnetotelluric surveys, telluric surveys, and time-domain electro-magnetic soundings and seismic surveys. Shaw Warm Springs appears to be the only source of thermal waters along the western side of the Valley. From the various investigations conducted the springs appear to be fault controlled and is very limited in extent. Based on best evidence presently available estimates are presented on the size and extent of Shaw Warm Springs thermal system. It is estimated that this could have an areal extent of 0.63 sq. miles (1.62 sq. km) and contain 0.0148 Q's of heat energy.

  12. Valley-controlled propagation of pseudospin states in bulk metacrystal waveguides

    Science.gov (United States)

    Chen, Xiao-Dong; Deng, Wei-Min; Lu, Jin-Cheng; Dong, Jian-Wen

    2018-05-01

    Light manipulations such as spin-direction locking propagation, robust transport, quantum teleportation, and reconfigurable electromagnetic pathways have been investigated at the boundaries of photonic systems. Recently by breaking Dirac cones in time-reversal-invariant photonic crystals, valley-pseudospin coupled edge states have been employed to realize selective propagation of light. Here, we realize the controllable propagation of pseudospin states in three-dimensional bulk metacrystal waveguides by valley degree of freedom. Reconfigurable photonic valley Hall effect is achieved for frequency-direction locking propagation in such a way that the propagation path can be tunable precisely by scanning the working frequency. A complete transition diagram is illustrated on the valley-dependent pseudospin states of Dirac-cone-absent photonic bands. A photonic blocker is proposed by cascading two inversion asymmetric metacrystal waveguides in which pseudospin-direction locking propagation exists. In addition, valley-dependent pseudospin bands are also discussed in a realistic metamaterials sample. These results show an alternative way toward molding the pseudospin flow in photonic systems.

  13. Valley-symmetric quasi-1D transport in ballistic graphene

    Science.gov (United States)

    Lee, Hu-Jong

    We present our recent studies on gate-defined valley-symmetric one-dimensional (1D) carrier guiding in ballistic monolayer graphene and valley-symmetry-protected topological 1D transport in ballistic bilayer graphene. Successful carrier guiding was realized in ballistic monolayer graphene even in the absence of a band gap by inducing a high distinction ( more than two orders of magnitude) in the carrier density between the region of a quasi-1D channel and the rest of the top-gated regions. Conductance of a channel shows quantized values in units of 4e2/ h, suggesting that the valley symmetry is preserved. For the latter, the topological 1D conduction was realized between two closely arranged insulating regions with inverted band gaps, induced under a pair of split dual gating with polarities opposite to each other. The maximum conductance along the boundary channel showed 4e2/ h, again with the preserved valley symmetry. The 1D topological carrier guiding demonstrated in this study affords a promising route to robust valleytronic applications and sophisticated valley-associated functionalities based on 2D materials. This work was funded by the National Research Foundation of Korea.

  14. Geohydrology and Water Quality of the Valley-Fill Aquifer System in the Upper Sixmile Creek and West Branch Owego Creek Valleys in the Town of Caroline, Tompkins County, New York

    Science.gov (United States)

    Miller, Todd S.

    2009-01-01

    In 2002, the U.S. Geological Survey, in cooperation with the Town of Caroline and Tompkins County Planning Department, began a study of the valley-fill aquifer system in upper Sixmile Creek and headwaters of West Branch Owego Creek valleys in the Town of Caroline, NY. The purpose of the study is to provide geohydrologic data to county and town planners as they develop a strategy to manage and protect their water resources. The first aquifer reach investigated in this series is in the Town of Caroline and includes the upper Sixmile Creek valley and part of West Branch Owego Creek valley. The portions of the valley-fill aquifer system that are comprised of saturated coarse-grained sediments including medium to coarse sand and sandy gravel form the major aquifers. Confined sand and gravel units form the major aquifers in the western and central portions of the upper Sixmile Creek valley, and an unconfined sand and gravel unit forms the major aquifer in the eastern portion of the upper Sixmile Creek valley and in the headwaters of the West Branch Owego Creek valley. The valley-fill deposits are thinnest near the edges of the valley where they pinch out along the till-mantled bedrock valley walls. The thickness of the valley fill in the deepest part of the valley, at the western end of the study area, is about 100 feet (ft); the thickness is greater than 165 ft on top of the Valley Heads Moraine in the central part of the valley. An estimated 750 people live over and rely on groundwater from the valley-fill aquifers in upper Sixmile Creek and West Branch Owego Creek valleys. Most groundwater withdrawn from the valley-fill aquifers is pumped from wells with open-ended 6-inch diameter casings; the remaining withdrawals are from shallow dug wells or cisterns that collect groundwater that discharges to springs (especially in the Brooktondale area). The valley-fill aquifers are the sources of water for about 200 households, several apartment complexes, two mobile home parks

  15. Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals

    KAUST Repository

    Li, Hang; Wang, Xuhui; Manchon, Aurelien

    2016-01-01

    We study spin-orbit torques in two-dimensional hexagonal crystals such as graphene, silicene, germanene, and stanene. The torque possesses two components, a fieldlike term due to inverse spin galvanic effect and an antidamping torque originating from Berry curvature in mixed spin-k space. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. The valley imbalance can be as high as 100% by tuning the bias voltage or magnetization angle. These findings open new venues for the development of current-driven spin-orbit torques by structural design.

  16. Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals

    KAUST Repository

    Li, Hang

    2016-01-11

    We study spin-orbit torques in two-dimensional hexagonal crystals such as graphene, silicene, germanene, and stanene. The torque possesses two components, a fieldlike term due to inverse spin galvanic effect and an antidamping torque originating from Berry curvature in mixed spin-k space. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. The valley imbalance can be as high as 100% by tuning the bias voltage or magnetization angle. These findings open new venues for the development of current-driven spin-orbit torques by structural design.

  17. Characterization of pottery from Cerro de Las Ventanas, Zacatecas, Mexico

    International Nuclear Information System (INIS)

    Lopez-del-Rio, H.; Mireles-Garcia, F.; Mendez-Cardona, R.Y.; Nicolas-Caretta, M.; Speakman, R.J.; Glascock, M.D.

    2009-01-01

    With the aim of classifying prehispanic pottery from Cerro de Las Ventanas site, Juchipila, Zacatecas, Mexico, instrumental neutron activation analysis (INAA) was used to analyze ceramic samples at the University of Missouri Research Reactor Center. Thirty-two chemical elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Two multivariate statistical methods, cluster analysis and principal component analysis, were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Mesoamerican ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Malpaso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de Las Ventanas represent a new and unique chemical fingerprint in the region. (orig.)

  18. Characterization of pottery from Cerro de Las Ventanas, Zacatecas, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-del-Rio, H.; Mireles-Garcia, F. [Unidad Academica de Estudios Nucleares, UAZ, Zacatecas (Mexico); Mendez-Cardona, R.Y. [Unidad Academica de Antropologia, UAZ, Zacatecas (Mexico); Nicolas-Caretta, M. [INAH Delegacion Zacatecas (Mexico); Coordinacion de Ciencias Sociales y Humanidades, UASLP, Fracc. Talleres, SLP (Mexico); Speakman, R.J. [Museum Conservation Inst., Smithsonian Institution, Suitland, MD (United States); Glascock, M.D. [Research Reactor Center, Univ. of Missouri, Columbia, MO (United States)

    2009-09-15

    With the aim of classifying prehispanic pottery from Cerro de Las Ventanas site, Juchipila, Zacatecas, Mexico, instrumental neutron activation analysis (INAA) was used to analyze ceramic samples at the University of Missouri Research Reactor Center. Thirty-two chemical elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Two multivariate statistical methods, cluster analysis and principal component analysis, were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Mesoamerican ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Malpaso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de Las Ventanas represent a new and unique chemical fingerprint in the region. (orig.)

  19. 9 CFR 93.427 - Cattle from Mexico.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cattle from Mexico. 93.427 Section 93... CONVEYANCE AND SHIPPING CONTAINERS Ruminants Mexico 10 § 93.427 Cattle from Mexico. (a) Cattle and other ruminants imported from Mexico, except animals being transported in bond for immediate return to Mexico or...

  20. 21 CFR 808.81 - New Mexico.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false New Mexico. 808.81 Section 808.81 Food and Drugs... and Local Exemptions § 808.81 New Mexico. The following New Mexico medical device requirement is... from preemption under section 521(b) of the act: New Mexico Statutes Annotated, section 67-36-16(F...

  1. West Valley Demonstration Project, West Valley, New York: Annual report

    International Nuclear Information System (INIS)

    1989-01-01

    Under the West Valley Demonstration Project Act, Public Law 96-368, liquid high-level radioactive waste stored at the Western New York Nuclear Services Center, West Valley, New York, that resulted from spent nuclear fuel reprocessing operations conducted between 1966 and 1972, is to be solidified in borosilicate glass and transported to a federal repository for geologic disposal. A major milestone was reached in May 1988 when the Project began reducing the volume of the liquid high-level waste. By the end of 1988, approximately 15 percent of the initial inventory had been processed into two waste streams. The decontaminated low-level liquid waste is being solidified in cement. The high-level waste stream is being stored in an underground tank pending its incorporation into borosilicate glass. Four tests of the waste glass melter system were completed. These tests confirmed equipment operability, control system reliability, and provided samples of waste glass for durability testing. In mid-1988, the Department validated an integrated cost and schedule plan for activities required to complete the production of the waste borosilicate glass. Design of the radioactive Vitrification Facility continued

  2. Medicinal plants of Usherai valley, Dir, NWFP, Pakistan

    International Nuclear Information System (INIS)

    Hazarat, A.; Shah, J.; Ahmad, S.; Nasir, M.; Jan, A.K.; Skindar

    2010-01-01

    This research is based on the results of an ethno-botanical research conducted in Usherai Valley. The main objective was to enlist the wealth of medicinal plants. In total 50 species, belonging to 32 families of wild herbs, shrubs and trees were found to be used as medicinal plants by the inhabitants in the valley. (author)

  3. AIR POLLUTION FEATURES OF THE VALLEY-BASED TOWNS IN HUNGARY

    Directory of Open Access Journals (Sweden)

    Z. UTASI

    2016-03-01

    Full Text Available There are 30 valley-based towns with >10,000 inhabitants in Hungary, filled by 1.023 million people i.e. 10 % of the population. Two criteria are used to define the valley-based town. They are: (i Vertical difference between the lowest point in the town and the highest one around it should be >100 m. At the same time, (ii the same difference on the opposite side should be >50 m. Air pollution data by the National Air Pollution Observation Network are used. Five contaminants were selected and analysed for 2007, 2010 and 2013. Due to a sharp reduction in the network, we could find data for a small part of the valley-based towns. Control towns with equal air-quality observations and similar cumulative number of inhabitants were also selected. The contaminants and the number of the settlements are: NO2 manual (14 valley-based vs. 2x14 control, NO2 automatic (8 vs. 8, SO2 automatic (7 vs. 2x6, PM10 automatic (8 vs. 2x7 and PM10 deposition manual (6 vs. 8. Average values, as well as high concentration episodes (>98%thresholds are equally analysed and evaluated. The main conclusion is that there are so big differences between the years both in absolute values and relative sequence of valley-based and control groups that the analysed there years is not enough to make any final conclusion. For step-over frequencies, however valley-based towns have some advantage, possibly due to the valley-hill wind system.

  4. Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO.

    Science.gov (United States)

    Grimsley, K J; Rathburn, S L; Friedman, J M; Mangano, J F

    2016-07-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  5. 76 FR 64248 - Gulf of Mexico Reef Fish Fishery; Closure of the 2011 Gulf of Mexico Commercial Sector for...

    Science.gov (United States)

    2011-10-18

    .... 040205043-4043-01] RIN 0648-XA766 Gulf of Mexico Reef Fish Fishery; Closure of the 2011 Gulf of Mexico... the commercial sector for greater amberjack in the exclusive economic zone (EEZ) of the Gulf of Mexico... Reef Fish Resources of the Gulf of Mexico (FMP). The FMP was prepared by the Gulf of Mexico Fishery...

  6. Groundwater quality in the Owens Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Owens Valley is one of the study areas being evaluated. The Owens study area is approximately 1,030 square miles (2,668 square kilometers) and includes the Owens Valley groundwater basin (California Department of Water Resources, 2003). Owens Valley has a semiarid to arid climate, with average annual rainfall of about 6 inches (15 centimeters). The study area has internal drainage, with runoff primarily from the Sierra Nevada draining east to the Owens River, which flows south to Owens Lake dry lakebed at the southern end of the valley. Beginning in the early 1900s, the City of Los Angeles began diverting the flow of the Owens River to the Los Angeles Aqueduct, resulting in the evaporation of Owens Lake and the formation of the current Owens Lake dry lakebed. Land use in the study area is approximately 94 percent (%) natural, 5% agricultural, and 1% urban. The primary natural land cover is shrubland. The largest urban area is the city of Bishop (2010 population of 4,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to the Owens Lake dry lakebed. The primary aquifers in Owens Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database

  7. New Mexico State Parks

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the generalized physical boundaries of New Mexico State Parks, in polygonal form with limited attributes, compiled using...

  8. Ground water in Fountain and Jimmy Camp Valleys, El Paso County, Colorado with a section on Computations of drawdowns caused by the pumping of wells in Fountain Valley

    Science.gov (United States)

    Jenkins, Edward D.; Glover, Robert E.

    1964-01-01

    The part of Fountain Valley considered in this report extends from Colorado Springs to the Pueblo County line. It is 23 miles long and has an area of 26 square miles. The part of Jimmy Camp Valley discussed is 11 miles long and has an area of 9 square miles. The topography is characterized by level flood plains and alluvial terraces that parallel the valley and by rather steep hills along the valley sides. The climate is semiarid, average annual precipitation being about 13 inches. Farming and stock raising are the principal occupations in the valleys; however, some of the agricultural land near Colorado Springs is being used for housing developments. The Pierre Shale and alluvium underlie most of the area, and mesa gravel caps the shale hills adjacent to Fountain Valley. The alluvium yields water to domestic, stock, irrigation, and public-supply wells and is capable of yielding large quantities of water for intermittent periods. Several springs issue along the sides of the valley at the contact of the mesa gravel and the underlying Pierre Shale. The water table ranges in depth from less than 10 feet along the bottom lands to about 80 feet along the sides of the valleys; the saturated thickness ranges from less than a foot to about 50 feet. The ground-water reservoir in Fountain Valley is recharged by precipitation that falls within the area, by percolation from Fountain Creek, which originates in the Pikes Peak, Monument Valley, and Rampart Range areas, and by seepage from irrigation water. This reservoir contains about 70,000 acre-feet of ground water in storage. The ground-water reservoir in Jimmy Camp Valley is recharged from precipitation that falls within the area, by percolation from Jimmy Camp Creek during periods of streamflow, and by seepage from irrigation water. The Jimmy Camp ground-water reservoir contains about 25,000 acre-feet of water in storage. Ground water is discharged from the area by movement to the south, by evaporation and transpiration in

  9. Valley-chiral quantum Hall state in graphene superlattice structure

    Science.gov (United States)

    Tian, H. Y.; Tao, W. W.; Wang, J.; Cui, Y. H.; Xu, N.; Huang, B. B.; Luo, G. X.; Hao, Y. H.

    2016-05-01

    We theoretically investigate the quantum Hall effect in a graphene superlattice (GS) system, in which the two valleys of graphene are coupled together. In the presence of a perpendicular magnetic field, an ordinary quantum Hall effect is found with the sequence σxy=ν e^2/h(ν=0,+/-1,+/-2,\\cdots) . At the zeroth Hall platform, a valley-chiral Hall state stemming from the single K or K' valley is found and it is localized only on one sample boundary contributing to the longitudinal conductance but not to the Hall conductivity. Our findings may shed light on the graphene-based valleytronics applications.

  10. Commercial production of ethanol in the San Luis Valley, Colorado. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hewlett, E.M.; Erickson, M.V.; Ferguson, C.D.; Boswell, B.S.; Walter, K.M.; Hart, M.L.; Sherwood, P.B.

    1983-07-01

    The commercial feasibility of producing between 76 and 189 million liters (20 to 50 million gallons) of ethanol annually in the San Luis Valley, Colorado using geothermal energy as the primary heat source was assessed. The San Luis Valley is located in south-central Colorado. The valley is a high basin situated approximately 2316 meters (7600 feet) above sea level which contains numerous warm water wells and springs. A known geothermal resource area (IGRA) is located in the east-central area of the valley. The main industry in the valley is agriculture, while the main industry in the surrounding mountains is lumber. Both of these industries can provide feedstocks for the production of ethanol.

  11. New Mexico Ghost Towns

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data provides locations and non-spatial attributes of many ghost towns in the State of New Mexico, compiled from various sources. Locations provided with...

  12. Cryostratigraphy and sedimentology of high-Arctic fjord-valleys

    OpenAIRE

    Gilbert, Graham Lewis

    2018-01-01

    Fjord-valleys, as sediment-filled palaeofjords, are characteristic of formerly glaciated mountainous coastal areas. High-Arctic fjord-valleys commonly host permafrost, but are poorly accessible and hence have drawn relatively little research. The research presented in this thesis combines the methods of cryostratigraphy, clastic sedimentology, sequence stratigraphy, geomorphology and geochronology to investigate the sedimentary infilling, permafrost formation and late Quaternary landscape dev...

  13. Electric power and environment in Mexico; Energia electrica y medio ambiente en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Quintanilla, J. [ed.] [UNAM IIE-PUE, Ciudad Universitaria (Mexico)

    1997-07-01

    This volume is one of the three resulting volumes about the project named Document analysis and prospective organized by the National Autonomous University of Mexico (UNAM) through it University Energy Program (PUE). It is a non-periodical publication collection of the variable content and extent that as a whole constitutes an information heritage and an original contribution about the energy problematic as International level as at the country context and the University activities. In this book the manners of producing electrical energy are discussed, so how satisfying the growing necessities of this energy in Mexico without contaminating environment and how doing rational and efficient use of energy. The content of each document of this book is however exclusive responsibility of authors, as in the information as in their told opinions. The following papers were presented: 1) Hydroelectricity, soils use and water management. 2) The electric generation in Mexico and its environmental impacts: Past, present and future. 3) The nucleo electricity and the radioactive materials management. 4) Exposure to electromagnetic fields and its association with leukemia in children. 5) The electric power in Mexico and the supportable development. 6) Potential of electric generation at great scale with eolic energy in Mexico. 7) Toward an electric generation scheme distributed with non-conventional energies. 8) Renewable sources of energy in Mexico at the Century 21. (Author)

  14. Large tunable valley splitting in edge-free graphene quantum dots on boron nitride

    Science.gov (United States)

    Freitag, Nils M.; Reisch, Tobias; Chizhova, Larisa A.; Nemes-Incze, Péter; Holl, Christian; Woods, Colin R.; Gorbachev, Roman V.; Cao, Yang; Geim, Andre K.; Novoselov, Kostya S.; Burgdörfer, Joachim; Libisch, Florian; Morgenstern, Markus

    2018-05-01

    Coherent manipulation of the binary degrees of freedom is at the heart of modern quantum technologies. Graphene offers two binary degrees: the electron spin and the valley. Efficient spin control has been demonstrated in many solid-state systems, whereas exploitation of the valley has only recently been started, albeit without control at the single-electron level. Here, we show that van der Waals stacking of graphene onto hexagonal boron nitride offers a natural platform for valley control. We use a graphene quantum dot induced by the tip of a scanning tunnelling microscope and demonstrate valley splitting that is tunable from -5 to +10 meV (including valley inversion) by sub-10-nm displacements of the quantum dot position. This boosts the range of controlled valley splitting by about one order of magnitude. The tunable inversion of spin and valley states should enable coherent superposition of these degrees of freedom as a first step towards graphene-based qubits.

  15. Georeferenced Population Datasets of Mexico (GEO-MEX): Urban Place GIS Coverage of Mexico

    Data.gov (United States)

    National Aeronautics and Space Administration — The Urban Place GIS Coverage of Mexico is a vector based point Geographic Information System (GIS) coverage of 696 urban places in Mexico. Each Urban Place is...

  16. Source characterization of major emission sources in the Imperial and Mexicali Valleys along the US/Mexico border

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.G.; Chow, J.C. [Desert Research Institute, 2215 Raggio Pkwy., 89512 Reno, NV (United States)

    2001-08-10

    Chemical profiles for particle emissions are needed for source apportionment studies using the chemical mass balance (CMB) receptor model. Source measurements of geological sources, motor vehicle exhaust, vegetative burning (e.g. asparagus, field burning, charbroil cooking), and industrial sources (e.g. oil-fueled glass plant, manure-fueled power plants) were acquired as part of the Imperial/Mexicali Valley Cross Border PM{sub 10} Transport Study in 1992. Six different source sampling techniques (i.e. hot- and diluted-exhaust sampling, ground-based source sampling, particle sweeping/grab sampling, vacuum sampling, and laboratory resuspension sampling) were applied to acquire filter samples of PM{sub 2.5} and PM{sub 10} (particulate matter with aerodynamic diameters <2.5 and 10 {mu}m, respectively). Filter samples were analyzed for mass by gravimetry, elements (Na to U) by X-ray fluorescence, anions (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup =}) by ion chromatography, ammonium (NH{sub 4}{sup +}) by automated colorimetry, soluble sodium (Na{sup +}) and potassium (K{sup +}) by atomic absorption spectrophotometry, and organic and elemental carbon (OC, EC) by thermal/optical reflectance. Concentration data were acquired for a total of 50 chemical species. Elevated abundances of crustal components (Al, Si, K, Ca, Fe) from geological material, carbon (OC, EC) and trace elements (Br, Pb) from vehicle exhausts, carbon (OC, EC) and ions (K{sup +}, Cl{sup -}) from vegetative burning, ions (SO{sub 4}{sup =}, NH{sub 4}{sup +}, Na{sup +}, K{sup +}, Cl{sup -}) and elements (Cl, Se) from a manure-fueled power plants, and sulfur and trace elements (Na{sup +}, Pb, Se, Ni, V) from an oil-fueled glass plant were found in the resulting source profiles. Abundances of crustal species (e.g. Al, Si, Ca) in the Imperial/Mexicali Valley geological profiles are more than twice those found in central and southern California. Abundances of lead in motor vehicle exhausts indicate different

  17. Completely independent electrical control of spin and valley in a silicene field effect transistor

    International Nuclear Information System (INIS)

    Zhai, Xuechao; Jin, Guojun

    2016-01-01

    One-atom-thick silicene is a silicon-based hexagonal-lattice material with buckled structure, where an electron fuses multiple degrees of freedom including spin, sublattice pseudospin and valley. We here demonstrate that a valley-selective spin filter (VSSF) that supports single-valley and single-spin transport can be realized in a silicene field effect transistor constructed of an npn junction, where an antiferromagnetic exchange field and a perpendicular electric field are applied in the p -doped region. The nontrivial VSSF property benefits from an electrically controllable state of spin-polarized single-valley Dirac cone. By reversing the electric field direction, the device can operate as a spin-reversed but valley-unreversed filter due to the dependence of band gap on spin and valley. Further, we find that all the possible spin-valley configurations of VSSF can be achieved just by tuning the electric field. Our findings pave the way to the realization of completely independent electrical control of spin and valley in silicene circuits. (paper)

  18. Hydrological, ecological, land use, economic, and sociocultural evidence for resilience of traditional irrigation communities in New Mexico, USA

    Science.gov (United States)

    Fernald, A.; Guldan, S.; Boykin, K.; Cibils, A.; Gonzales, M.; Hurd, B. H.; Lopez, S.; Ochoa, C. G.; Ortiz, M.; Rivera, J.; Rodriguez, S.; Steele, C. M.

    2014-02-01

    Southwestern US irrigated landscapes are facing upheaval due to climate change-induced water scarcity and economic change-induced land use conversion. Clues to community longevity are found in the traditionally irrigated valleys of northern New Mexico. Human systems have interacted with hydrologic processes over the last 400 yr in river fed irrigated valleys to create linked systems. In this study, we asked if concurrent data from multiple disciplines show that human adapted hydrologic and socioeconomic systems have created conditions for resilience. We identify and describe several areas of resilience: hydrological, ecological, land use, economic, and sociocultural. We found that there are multiple hydrologic benefits of the water seepage from the traditional irrigation systems; it recharges groundwater that recharges rivers, supports threatened biodiversity by maintaining riparian vegetation, and ameliorates impacts of climate change by prolonging streamflow hydrographs. In terms of land use and economics, place-based adaptability manifests itself in transformations of irrigation infrastructure and specific animal and crop systems; as grazing has diminished over time on public land watersheds, it has increased on irrigated valley pastures while outside income allows irrigators to retain their land. Sociocultural evidence shows that traditional local knowledge about the hydrosocial cycle of acequia operations is a key factor in acequia resilience. When irrigators are confronted with unexpected disturbances or changing climate that affect water supply, they adapt specific practices while maintaining community cohesion. Our ongoing work will quantify the multiple disciplinary components of these systems, translate them into a common language of causal loop diagrams, and model future scenarios to identify thresholds and tipping points of sustainability. Early indications are that these systems are not immune to upheaval, but have astonishing resilience.

  19. California-Mexico gas exports eyed

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that two California utilities have proposed providing natural gas transportation services to Mexico. The arrangement would provide a second U.S. export sales point at the U.S.-Mexico border and perhaps help alleviate an expected surplus of gas pipeline capacity available to California. Mexico currently imports about 200 MMcfd of U.S. gas via pipelines in Texas

  20. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1987-01-01

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  1. Commercial production of ethanol in the San Luis Valley, Colorado. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hewlett, E.M.; Erickson, M.V.; Ferguson, C.D.; Sherwood, P.B.; Boswell, B.S.; Walter, K.M.; Hart, M.L.

    1983-07-01

    The purpose of this study is to assess the commercial feasibility of producing between 76 and 189 million liters (20 and 50 million gallons) of ethanol annually in the San Luis Valley, Colorado using geothermal energy as the primary heat source. The San Luis Valley is located in south-central Colorado. The valley is a high basin situated approximately 2316 meters (7600 feet) above sea level which contains numerous warm water wells and springs. A known geothermal resource area (KGRA) is located in the east-central area of the valley. The main industry in the valley is agriculture, while the main industry in the surrounding mountains is lumber. Both of these industries can provide feedstock for the production of ethanol.

  2. Socio-hydrological resilience of an arid aquifer system, subject to changing climate and inadequate agricultural management: A case study from the Valley of Santo Domingo, Mexico

    Science.gov (United States)

    Wurl, Jobst; Gámez, Alba E.; Ivanova, Antonina; Imaz Lamadrid, Miguel A.; Hernández-Morales, Pablo

    2018-04-01

    Mismanagement has caused the overexploitation of one third of the major aquifers in Mexico, mainly due to excessive water extraction for agricultural irrigation. Santo Domingo (Baja California Sur, in northern Mexico, where agriculture absorbs nearly 80% of water) is the only aquifer in the Mexico where, after a period of overexploitation, equality between extraction and recharge rates was achieved, although this has not meant the securement of long-term water availability. This paper offers an analysis of hydrological resilience of a water-limited arid ecosystem under future extraction scenarios and changing climate conditions. A regional groundwater flow model is proposed using MODFLOW software. Then, different indicators were modeled as outcomes of coupled human-water systems to predict water trajectories under different human impacts. The aim was to recognize water insecurity scenarios and define appropriate actions to a more sustainable use of this scarce resource in the region. Thus, although runoff derived from extreme floods may favor infiltration, the involvement of local stakeholders and decision makers to reverse the adverse impacts of current water management and climate change is imperative if water availability and better quality are to be secured.

  3. Mexico.

    Science.gov (United States)

    1993-01-01

    The background notes on Mexico provide text and recent statistical information on the geography, population, government, economy, and foreign relations, specifically the North American Free Trade Agreement with US. The 1992 population is estimated at 89 million of which 60% are mestizo (Indian-Spanish), 30% are American Indian, 9% are Caucasian, and 1% are other. 90% are Roman Catholic. There are 8 years of compulsory education. Infant mortality is 30/1000 live births. Life expectancy for males is 68 years and 76 years for females. The labor force is comprised of 30% in services, 24% in agriculture and fishing, 19% in manufacturing, 13% in commerce, 7% in construction, 4% in transportation and communication, and .4% in mining. There are 31 states and a federal district. Gross domestic product (GDP) per capita was $3200 in 1991. Military expenditures were .5% of GDP in 1991. The average inflation rate is 19%. Mexico City with 20 million is the largest urban center in the world. In recent years, the economy has been restructured with market oriented reforms; the result has been a growth of GDP of 3.6% in 1991 from 2% in 1987. Dependence on oil exports has decreased. There has been privatization and deregulation of state-owned companies. Subsidies to inefficient companies have been stopped. Tariff rates were reduced. The financial debt has been reduced and turned into a surplus of .8% in 1992. Mexico's foreign debt has been reduced from its high in 1987 of $107 billion. Agricultural reforms have been ongoing for 50 years. Land was redistributed, but standards of living and productivity have improved only slightly. Rural land tenure regulations have been changed, and other economic reforms are expected. Mexico engages in ad hoc international groups and is selective about membership in international organizations.

  4. Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers

    KAUST Repository

    Kim, J.

    2014-12-04

    The valley pseudospin is a degree of freedom that emerges in atomically thin two-dimensional transition metal dichalcogenides (MX2). The capability to manipulate it, in analogy to the control of spin in spintronics, can open up exciting opportunities. Here, we demonstrate that an ultrafast and ultrahigh valley pseudo-magnetic field can be generated by using circularly polarized femtosecond pulses to selectively control the valley degree of freedom in monolayer MX2. Using ultrafast pump-probe spectroscopy, we observed a pure and valley-selective optical Stark effect in WSe2 monolayers from the nonresonant pump, resulting in an energy splitting of more than 10 milli-electron volts between the K and K′ valley exciton transitions. Our study opens up the possibility to coherently manipulate the valley polarization for quantum information applications.

  5. Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers

    KAUST Repository

    Kim, J.; Hong, X.; Jin, C.; Shi, S.-F.; Chang, C.-Y. S.; Chiu, Ming-Hui; Li, Lain-Jong; Wang, F.

    2014-01-01

    The valley pseudospin is a degree of freedom that emerges in atomically thin two-dimensional transition metal dichalcogenides (MX2). The capability to manipulate it, in analogy to the control of spin in spintronics, can open up exciting opportunities. Here, we demonstrate that an ultrafast and ultrahigh valley pseudo-magnetic field can be generated by using circularly polarized femtosecond pulses to selectively control the valley degree of freedom in monolayer MX2. Using ultrafast pump-probe spectroscopy, we observed a pure and valley-selective optical Stark effect in WSe2 monolayers from the nonresonant pump, resulting in an energy splitting of more than 10 milli-electron volts between the K and K′ valley exciton transitions. Our study opens up the possibility to coherently manipulate the valley polarization for quantum information applications.

  6. The environmental policy in Mexico: Crisis and perspectives; La politica ambiental en Mexico: Crisis y perspectivas

    Energy Technology Data Exchange (ETDEWEB)

    Urquidi, Victor [Colegio de Mexico, Mexico, D. F. (Mexico)

    1997-12-31

    In this paper some aspects of the environmental situation in Mexico are condensed. The main roll performed by the modality of the energy resources consumption and the evolution of the environmental policy in Mexico from 1971 to 1996 is analyzed. It is concluded that in Mexico it has not been able to define the environmental policy in all its extension requiring, therefore, a greater participation of all the sectors to protect Nature and fight against the industrial and municipal pollution [Espanol] En esta ponencia se resumen algunos aspectos de la situacion ambiental actual de Mexico. Se analiza el papel central desempenado por la modalidad del consumo de energeticos y la evolucion de la politica ambiental en Mexico desde 1971 hasta 1996. Se concluye en que la politica ambiental en Mexico no se ha podido definir todavia en todos sus alcances por lo que se requiere una mayor participacion de todos los sectores para proteger la naturaleza y combatir la contaminacion industrial y municipal

  7. The environmental policy in Mexico: Crisis and perspectives; La politica ambiental en Mexico: Crisis y perspectivas

    Energy Technology Data Exchange (ETDEWEB)

    Urquidi, Victor [Colegio de Mexico, Mexico, D. F. (Mexico)

    1996-12-31

    In this paper some aspects of the environmental situation in Mexico are condensed. The main roll performed by the modality of the energy resources consumption and the evolution of the environmental policy in Mexico from 1971 to 1996 is analyzed. It is concluded that in Mexico it has not been able to define the environmental policy in all its extension requiring, therefore, a greater participation of all the sectors to protect Nature and fight against the industrial and municipal pollution [Espanol] En esta ponencia se resumen algunos aspectos de la situacion ambiental actual de Mexico. Se analiza el papel central desempenado por la modalidad del consumo de energeticos y la evolucion de la politica ambiental en Mexico desde 1971 hasta 1996. Se concluye en que la politica ambiental en Mexico no se ha podido definir todavia en todos sus alcances por lo que se requiere una mayor participacion de todos los sectores para proteger la naturaleza y combatir la contaminacion industrial y municipal

  8. The lakes of the Jordan Rift Valley

    International Nuclear Information System (INIS)

    Gat, J.R.

    2001-01-01

    This paper presents a summary of the proceedings of a workshop on the Lakes of the Jordan Rift Valley that was held in conjunction with the CRP on The Use of Isotope Techniques in Lake Dynamics Investigations. The paper presents a review of the geological, hydrogeological and physical limnological setting of the lakes in the Jordan Rift Valley, Lake Hula, Lake Kinneret and the Dead Sea. This is complemented by a description of the isotope hydrology of the system that includes the use of a wide range of isotopes: oxygen-18, deuterium, tritium, carbon-14, carbon-13, chlorine isotopes, boron-11 and helium-3/4. Environmental isotope aspects of the salt balances of the lakes, their palaeolimnology and biogeochemical tracers are also presented. The scope of application of isotopic tracers is very broad and provides a clear insight into many aspects of the physical, chemical and biological limnology of the Rift Valley Lakes. (author)

  9. 77 FR 56168 - Reef Fish Fishery of the Gulf of Mexico; Gulf of Mexico Individual Fishing Quota Programs

    Science.gov (United States)

    2012-09-12

    .... 090206140-91081-03] RIN 0648-XC227 Reef Fish Fishery of the Gulf of Mexico; Gulf of Mexico Individual... red snapper and grouper/tilefish components of the reef fish fishery in the Gulf of Mexico (Gulf), the... INFORMATION: The reef fish fishery of the Gulf of Mexico is managed under the Fishery Management Plan for Reef...

  10. West Valley Reprocessing Plant. Safety analysis plant, supplement 18

    International Nuclear Information System (INIS)

    1975-01-01

    Supplement 18 contains the following additions to Appendix II--5.0 Geology and Seismology: Section 12 ''Seismic Investigations for Spent Fuel Reprocessing Facility at West Valley, New York,'' October 20, 1975, and Section 13 ''Earthquake Return Period Analysis at West Valley, New York, for Nuclear Fuel Services, Inc.'' November 5, 1975

  11. Wind Regimes in Complex Terrain of the Great Valley of Eastern Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Birdwell, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2011-05-01

    This research was designed to provide an understanding of physical wind mechanisms within the complex terrain of the Great Valley of Eastern Tennessee to assess the impacts of regional air flow with regard to synoptic and mesoscale weather changes, wind direction shifts, and air quality. Meteorological data from 2008 2009 were analyzed from 13 meteorological sites along with associated upper level data. Up to 15 ancillary sites were used for reference. Two-step complete linkage and K-means cluster analyses, synoptic weather studies, and ambient meteorological comparisons were performed to generate hourly wind classifications. These wind regimes revealed seasonal variations of underlying physical wind mechanisms (forced channeled, vertically coupled, pressure-driven, and thermally-driven winds). Synoptic and ambient meteorological analysis (mixing depth, pressure gradient, pressure gradient ratio, atmospheric and surface stability) suggested up to 93% accuracy for the clustered results. Probabilistic prediction schemes of wind flow and wind class change were developed through characterization of flow change data and wind class succession. Data analysis revealed that wind flow in the Great Valley was dominated by forced channeled winds (45 67%) and vertically coupled flow (22 38%). Down-valley pressure-driven and thermally-driven winds also played significant roles (0 17% and 2 20%, respectively), usually accompanied by convergent wind patterns (15 20%) and large wind direction shifts, especially in the Central/Upper Great Valley. The behavior of most wind regimes was associated with detectable pressure differences between the Lower and Upper Great Valley. Mixing depth and synoptic pressure gradients were significant contributors to wind pattern behavior. Up to 15 wind classes and 10 sub-classes were identified in the Central Great Valley with 67 joined classes for the Great Valley at-large. Two-thirds of Great Valley at-large flow was defined by 12 classes. Winds

  12. Size effects in many-valley fluctuations in semiconductors

    International Nuclear Information System (INIS)

    Sokolov, V.N.; Kochelap, V.A.

    1995-08-01

    We present the results of theoretical investigations of nonhomogeneous fluctuations in submicron active regions of many-valley semiconductors with equivalent valleys(Ge, Si-type), where the dimension 2d of the region is comparable to or less than the intervalley diffusion relaxation length L iv . It is shown that for arbitrary orientations of the valley axes (the crystal axes) with respect to lateral sample surfaces, the fluctuation spectra depend on the bias voltage applied to the layer in the region of weak nonheating electric fields. The new physical phenomenon is reported: the fluctuation spectra depend on the sample thickness, with 2d iv the suppression of fluctuations arises for fluctuation frequencies ω -1 iv , τ -1 iv is the characteristic intervalley relaxation time. (author). 43 refs, 5 figs

  13. [Aging in Mexico].

    Science.gov (United States)

    Contreras de Lehr, E

    1986-01-01

    Demographic social and economic aspects of the situation of the elderly in Mexico are described with special emphasis upon education programmes and types of care in nursing homes. Considering the future trends of an increase in Mexico's elderly population, the author calls for more efforts in research and training in the field of gerontology. First results in this area are reported.

  14. Mexico and the CTBT; Mexico y el CTBT

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre G, J.; Martinez L, J.; Ruiz E, L. J.; Aragon M, I. B., E-mail: jaguirre@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

    2013-10-15

    The Comprehensive Nuclear Test-Ban-Treaty (CTBT) is a treaty that prohibits all the nuclear explosions by anybody and in any place, either on the terrestrial surface, in the atmosphere, under the sea or underground. From the adoption of this Treaty by the United Nations, Mexico has had interest for its entrance in vigor, as integral part to assure the international peace. For this reason, our country signed the Treaty since it was open in September 24, 1996 and three years later ratified it, due to Mexico is part of the group of necessary countries for their entrance in vigor. During 13 years, the country has been committed and helped to the installation of monitoring stations, actions that allow the strengthening of the International System of Surveillance. The purpose of this work is to divulge the Treaty,its technologies and benefits; and also to diffuse the works realized by Mexico regarding the radionuclides monitoring station and noble gases both certified ones for the CTBT. Besides the radionuclides technology, Mexico has taken charge of the installation and operation of the seismic stations and hydro-acoustics that have been certified too. The radionuclides station Rn-44 located in Guerrero Negro, BCS has two technologies, an automated sampler of suspended particles in air brand Cinderella/ARAME and a noble gases system Sauna used for the particles detection of radioactive material gamma emitting and Xenon radioisotopes product of nuclear assays. Both technologies are transmitting data in real time to the International Center of Data. These technologies are shown in this work. (Author)

  15. Energy Band Gap Dependence of Valley Polarization of the Hexagonal Lattice

    Science.gov (United States)

    Ghalamkari, Kazu; Tatsumi, Yuki; Saito, Riichiro

    2018-02-01

    The origin of valley polarization of the hexagonal lattice is analytically discussed by tight binding method as a function of energy band gap. When the energy gap decreases to zero, the intensity of optical absorption becomes sharp as a function of k near the K (or K') point in the hexagonal Brillouin zone, while the peak intensity at the K (or K') point keeps constant with decreasing the energy gap. When the dipole vector as a function of k can have both real and imaginary parts that are perpendicular to each other in the k space, the valley polarization occurs. When the dipole vector has only real values by selecting a proper phase of wave functions, the valley polarization does not occur. The degree of the valley polarization may show a discrete change that can be relaxed to a continuous change of the degree of valley polarization when we consider the life time of photo-excited carrier.

  16. Asymmetric valley-resolved beam splitting and incident modes in slanted graphene junctions

    International Nuclear Information System (INIS)

    Hsieh, S. H.; Chu, C. S.

    2016-01-01

    Electron injection into a graphene sheet through a slanted armchair graphene nanoribbon (AGNR) is investigated. An incident mode, or subband, in the AGNR is valley-unpolarized. Our attention is on the valley-resolved nature of the injected electron beams and its connection to the incident mode. It is known for a normal injection that an incident mode will split symmetrically into two valley-resolved beams of equal intensity. We show, in contrast, that slanted injections result in asymmetric valley-resolved beam splitting. The most asymmetric beam splitting cases, when one of the valley-resolved beams has basically disappeared, are found and the condition derived. This is shown not due to trigonal warping because it holds even in the low incident energy regime, as long as collimation allows. These most asymmetric beam splitting cases occur at energies within an energy interval near and include the subband edge of an incident mode. The physical picture is best illustrated by a projection of the slanted AGNR subband states onto that of the 2D graphene sheet. It follows that the disappearing of a valley-resolved beam coincides with the situation that the group velocities of the projected states in the corresponding valley are in backward directions

  17. The Drentsche Aa valley system

    International Nuclear Information System (INIS)

    Gans, W. de.

    1981-01-01

    This thesis is composed of five papers concerned with Late Quaternary geology and geomorphology of the Aa valley system. The correlation and chronostratigraphic position of the layers have been established by radiocarbon dating. (Auth.)

  18. Land Subsidence Caused by Groundwater Exploitation in Quetta Valley, Pakistan

    Directory of Open Access Journals (Sweden)

    Najeebullah Kakar

    2016-12-01

    Full Text Available Land subsidence is affecting several metropolitan cities in developing as well as developed countries around the world such as Nagoya (Japan, Shanghai (China, Venice (Italy and San Joaquin valley (United States. This phenomenon is attributed to natural as well as anthropogenic activities that include extensive groundwater withdrawals. Quetta is the largest city of Balochistan province in Pakistan. This valley is mostly dry and ground water is the major source for domestic and agricultural consumption. The unplanned use of ground water resources has led to the deterioration of water quality and quantity in the Quetta valley. Water shortage in the region was further aggravated by the drought during (1998-2004 that hit the area forcing people to migrate from rural to urban areas. Refugees from the war torn neighboring Afghanistan also contributed to rapid increase in population of Quetta valley that has increased from 0.26 million in 1975 to 3.0 million in 2016. The objective of this study was to measure the land subsidence in Quetta valley and identify the effects of groundwater withdrawals on land subsidence. To achieve this goal, data from five Global Positioning System (GPS stations were acquired and processed. Furthermore the groundwater decline data from 41 observation wells during 2010 to 2015 were calculated and compared with the land deformation. The results of this study revealed that the land of Quetta valley is subsiding from 30mm/y on the flanks to 120 mm/y in the central part. 1.5-5.0 m/y of groundwater level drop was recorded in the area where the rate of subsidence is highest. So the extensive groundwater withdrawals in Quetta valley is considered to be the driving force behind land subsidence.

  19. Direct measurement of exciton valley coherence in monolayer WSe2

    KAUST Repository

    Hao, Kai; Moody, Galan; Wu, Fengcheng; Dass, Chandriker Kavir; Xu, Lixiang; Chen, Chang Hsiao; Sun, Liuyang; Li, Ming-yang; Li, Lain-Jong; MacDonald, Allan H.; Li, Xiaoqin

    2016-01-01

    In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge

  20. Seismic study of soil dynamics at Garner Valley, California

    International Nuclear Information System (INIS)

    Archuleta, R.J.; Seale, S.H.

    1990-01-01

    The Garner Valley downhole array (GVDA) of force-balanced accelerometers was designed to determine the effect that near-surface soil layers have on surface ground motion by measuring in situ seismic waves at various depths. Although there are many laboratory, theoretical and numerical studies that are used to predict the effects that local site geology might have on seismic waves, there are very few direct measurements that can be used to confirm the predictions made by these methods. The effects of local site geology on seismic ground motions are critical for estimating the base motion of structures. The variations in site amplifications at particular periods can range over a factor of 20 or more in comparing amplitude spectra from rock and soil sites, e.g., Mexico City (1985) or San Francisco (1989). The basic phenomenon of nonlinear soil response, and by inference severe attenuation of seismic waves, has rarely been measured although it is commonly observed in laboratory experiments. The basic question is whether or not the local site geology amplifies are attenuates the seismic ground motion. Because the answer depends on the interaction between the local site geology and the amplitude as well as the frequency content of the incoming seismic waves, the in situ measurements must sample the depth variations of the local structure as well as record seismic waves over as wide a range as possible in amplitude and frequency

  1. Valley polarization in magnetically doped single-layer transition-metal dichalcogenides

    KAUST Repository

    Cheng, Yingchun

    2014-04-28

    We demonstrate that valley polarization can be induced and controlled in semiconducting single-layer transition-metal dichalcogenides by magnetic doping, which is important for spintronics, valleytronics, and photonics devices. As an example, we investigate Mn-doped MoS2 by first-principles calculations. We study how the valley polarization depends on the strength of the spin orbit coupling and the exchange interaction and discuss how it can be controlled by magnetic doping. Valley polarization by magnetic doping is also expected for other honeycomb materials with strong spin orbit coupling and the absence of inversion symmetry.

  2. Optically initialized robust valley-polarized holes in monolayer WSe2

    KAUST Repository

    Hsu, Wei-Ting; Chen, Yen-Lun; Chen, Chiang-Hsiao; Liu, Pang-Shiuan; Hou, Tuo-Hung; Li, Lain-Jong; Chang, Wen-Hao

    2015-01-01

    a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time

  3. Uranium resources in New Mexico

    International Nuclear Information System (INIS)

    McLemore, V.T.; Chenoweth, W.L.

    1989-01-01

    For nearly three decades (1951-1980), the Grants uranium district in northwestern New Mexico produced more uranium than any other district in the world. The most important host rocks containing economic uranium deposits in New Mexico are sandstones within the Jurassic Morrison Formation. Approximately 334,506,000 lb of U 3 O 8 were produced from this unit from 1948 through 1987, accounting for 38% of the total uranium production from the US. All of the economic reserves and most of the resources in New Mexico occur in the Morrison Formation. Uranium deposits also occur in sandstones of Paleozoic, Triassic, Cretaceous, Tertiary, and Quaternary formations; however, only 468,680 lb of U 3 O 8 or 0.14% of the total production from New Mexico have been produced from these deposits. Some of these deposits may have a high resource potential. In contrast, almost 6.7 million lb of U 3 O 8 have been produced from uranium deposits in the Todilto Limestone of the Wanakah Formation (Jurassic), but potential for finding additional economic uranium deposits in the near future is low. Other uranium deposits in New Mexico include those in other sedimentary rocks, vein-type uranium deposits, and disseminated magmatic, pegmatitic, and contact metasomatic uranium deposits in igneous and metamorphic rocks. Production from these deposits have been insignificant (less than 0.08% of the total production from New Mexico), but there could be potential for medium to high-grade, medium-sized uranium deposits in some areas. Total uranium production from New Mexico from 1948 to 1987 amounts to approximately 341,808,000 lb of U 3 O 8 . New Mexico has significant uranium reserves and resources. Future development of these deposits will depend upon an increase in price for uranium and lowering of production costs, perhaps by in-situ leaching techniques

  4. Interaction of valleys and circulation patterns (CPs on spatial precipitation patterns in southern Germany

    Directory of Open Access Journals (Sweden)

    M. Liu

    2013-11-01

    Full Text Available Topography exerts influence on the spatial precipitation distribution over different scales, known typically at the large scale as the orographic effect, and at the small scale as the wind-drift rainfall (WDR effect. At the intermediate scale (1~10 km, which is characterized by secondary mountain valleys, topography also demonstrates some effect on the precipitation pattern. This paper investigates such intermediate-scale topographic effects on precipitation patterns, focusing on narrow-steep valleys in the complex terrain of southern Germany, based on the daily observations over a 48 yr period (1960~2007 from a high-density rain-gauge network covering two sub-areas, Baden-Wuerttemberg (BW and Bavaria (BY. Precipitation data at the valley and non-valley stations are compared under consideration of the daily general circulation patterns (CPs classified by a fuzzy rule-based algorithm. Scatter plots of precipitation against elevation demonstrate a different behavior of valley stations comparing to non-valley stations. A detailed study of the precipitation time series for selected station triplets, each consisting of a valley station, a mountain station and an open station have been investigated by statistical analysis with the Kolmogorov–Smirnov (KS test supplemented by the One-way analysis of variance (One-way ANOVA and a graphical comparison of the mean precipitation amounts. The results show an interaction of valley orientation and the direction of the CPs at the intermediate scale, i.e. when the valley is shielded from the CP which carries the precipitation, the precipitation amount within the valley is comparable to that on the mountain crest, and both larger than the precipitation at the open station. When the valley is open to the CP, the precipitation within the valley is similar to the open station but much less than that on the mountain. Such phenomenon where the precipitation is "blind" to the valleys at the intermediate scale

  5. Valley plugs, land use, and phytogeomorphic response: Chapter 14

    Science.gov (United States)

    Pierce, Aaron R.; King, Sammy L.; Shroder, John F.

    2013-01-01

    Anthropogenic alteration of fluvial systems can disrupt functional processes that provide valuable ecosystem services. Channelization alters fluvial parameters and the connectivity of river channels to their floodplains which is critical for productivity, nutrient cycling, flood control, and biodiversity. The effects of channelization can be exacerbated by local geology and land-use activities, resulting in dramatic geomorphic readjustments including the formation of valley plugs. Considerable variation in the response of abiotic processes, including surface hydrology, subsurface hydrology, and sedimentation dynamics, to channelization and the formation of valley plugs. Altered abiotic processes associated with these geomorphic features and readjustments influence biotic processes including species composition, abundance, and successional processes. Considerable interest exists for restoring altered fluvial systems and their floodplains because of their social and ecological importance. Understanding abiotic and biotic responses of channelization and valley-plug formation within the context of the watershed is essential to successful restoration. This chapter focuses on the primary causes of valley-plug formation, resulting fluvial-geomorphic responses, vegetation responses, and restoration and research needs for these systems.

  6. Magnetoelectric control of valley and spin in a silicene nanoribbon modulated by the magnetic superlattices

    Energy Technology Data Exchange (ETDEWEB)

    An, Xing-Tao, E-mail: anxt@hku.hk

    2015-03-20

    The control of valley and spin degrees of freedom and the transport properties of electrons in a zigzag silicene nanoribbon modulated by the magnetic superlattices are investigated theoretically. Due to the valley–spin locking effect in silicene, the valley degree of freedom can be controlled by magnetic means. The valley or/and spin selection induced by the exchange field result in the perfect spin–valley filter and tunneling magnetoresistance effect in the double ferromagnetic barriers on the surface of the silicene nanoribbon. It is more interesting that there are valley-resolved minigaps and minibands in the zigzag silicene nanoribbon modulated by the magnetic superlattices which give rise to the periodically modulated spin (or/and valley) polarization and tunneling magnetoresistance. The results obtained may have certain practical significance in applications for future valleytronic and spintronic devices. - Highlights: • The valley can be controlled by a magnetic field in silicene. • The valley-resolved miniband transport is studied in the silicene superlattices. • There are the perfect spin–valley filter and tunneling magnetoresistance effect.

  7. Subsidence Induced Faulting Hazard risk maps in Mexico City and Morelia, central Mexico

    Science.gov (United States)

    Cabral-Cano, E.; Solano-Rojas, D.; Hernández-Espriu, J.; Cigna, F.; Wdowinski, S.; Osmanoglu, B.; Falorni, G.; Bohane, A.; Colombo, D.

    2012-12-01

    Subsidence and surface faulting have affected urban areas in Central Mexico for decades and the process has intensified as a consequence of urban sprawl and economic growth. This process causes substantial damages to the urban infrastructure and housing structures and in several cities it is becoming a major factor to be considered when planning urban development, land use zoning and hazard mitigation strategies in the next decades. Subsidence is usually associated with aggressive groundwater extraction rates and a general decrease of aquifer static level that promotes soil consolidation, deformation and ultimately, surface faulting. However, local stratigraphic and structural conditions also play an important role in the development and extension of faults. Despite its potential for damaging housing, and other urban infrastructure, the economic impact of this phenomena is poorly known, in part because detailed, city-wide subsidence induced faulting risk maps have not been published before. Nevertheless, modern remote sensing techniques are most suitable for this task. We present the results of a risk analysis for subsidence induced surface faulting in two cities in central Mexico: Morelia and Mexico City. Our analysis in Mexico City and Morelia is based on a risk matrix using the horizontal subsidence gradient from a Persistent Scatterer InSAR (Morelia) and SqueeSAR (Mexico City) analysis and 2010 census population distribution data from Mexico's National Institute of Statistics and Geography. Defining subsidence induced surface faulting vulnerability within these urbanized areas is best determined using both magnitude and horizontal subsidence gradient. Our Morelia analysis (597,000 inhabitants with localized subsidence rates up to 80 mm/yr) shows that 7% of the urbanized area is under a high to very high risk level, and 14% of its population (11.7% and 2.3% respectively) lives within these areas. In the case of the Mexico City (15'490,000 inhabitants for the

  8. 75 FR 48359 - Blackstone River Valley National Heritage Corridor Commission: Notice of Meeting

    Science.gov (United States)

    2010-08-10

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Blackstone River Valley National Heritage..., United States Code, that a meeting of the John H. Chafee Blackstone River Valley National Heritage..., Blackstone River Valley National Heritage Corridor Commission, One Depot Square, Woonsocket, RI 02895, Tel...

  9. Rock-fall potential in the Yosemite Valley, California

    Science.gov (United States)

    Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

    1999-01-01

    We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

  10. 9 CFR 93.325 - Horses from Mexico.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Horses from Mexico. 93.325 Section 93... CONVEYANCE AND SHIPPING CONTAINERS Horses Mexico 18 § 93.325 Horses from Mexico. Horses offered for entry from Mexico shall be inspected as provided in §§ 93.306 and 93.323; shall be accompanied by a...

  11. 7 CFR 319.8-13 - From Northwest Mexico.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false From Northwest Mexico. 319.8-13 Section 319.8-13... for the Entry of Cotton and Covers from Mexico § 319.8-13 From Northwest Mexico. Contingent upon continued freedom of Northwest Mexico and of the West Coast of Mexico from infestations of the pink bollworm...

  12. Radiation processing of temperate fruits of Kashmir valley

    International Nuclear Information System (INIS)

    Hussain, Peerzada R.; Meena, Raghuveer S.; Dar, Mohd A.; Wani, Ali M.

    2011-01-01

    Kashmir valley is famous for its temperate horticulture. Main temperate fruits grown commercially in the valley include apple, pear, peach, plum, cherry, strawberry and apricot. These fruits being perishable and susceptible to microbial spoilage, have a short shelf-life. The short shelf-life in an impediment in their transportation and marketing and results in huge losses. Study was carried out at NRL, Srinagar to investigate the effect of gamma irradiation on the keeping quality of most of these fruits. The effect of gamma irradiation alone and in combination with other techniques like controlled low temperature storage, edible polysaccharide coating and calcium chloride treatment was studied in detail. The results revealed that there is a great potential for the use of radiation in extending the storage life of most of the temperate fruits produced in the valley of Kashmir. (author)

  13. Regolith transport in the Dry Valleys of Antarctica

    Science.gov (United States)

    Putkonen, J.; Rosales, M.; Turpen, N.; Morgan, D.; Balco, G.; Donaldson, M.

    2007-01-01

    The stability of ground surface and preservation of landforms that record past events and environments is of great importance as the geologic and climatic history is evaluated in the Dry Valleys of Antarctica. Currently little is known about the regolith transport that tends to eradicate and confound this record and regolith transport is itself an environmental indicator. Based on analyses of repeat photographs, soil traps, and pebble transport distances, it was found that there is a large spatial variation in topographic diffusivities at least in the annual basis and that counter intuitively the highest topographic diffusivities are found in the alpine valleys that are located farther inland from the coast where the lowest topographic diffusivities were recorded. An average topographic diffusivity for the Dry Valleys was determined to be 10M-5–10-4 m2

  14. Distribution and movements of female northern pintails radiotagged in San Joaquin Valley, California

    Science.gov (United States)

    Fleskes, Joseph P.; Jarvis, Robert L.; Gilmer, David S.

    2002-01-01

    To improve understanding of northern pintail (Anas acuta) distribution in central California (CCA), we radiotagged 191 Hatch-Year (HY) and 228 After-Hatch-Year (AHY) female northern pintails during late August-early October, 1991-1993, in the San Joaquin Valley (SJV) and studied their movements through March each year. Nearly all (94.3%) wintered in CCA, but 5.7% went to southern California, Mexico, or unknown areas; all that went south left before hunting season. Of the 395 radiotagged pintails that wintered in CCA, 83% flew from the SJV north to other CCA areas (i.e., Sacramento Valley [SACV], Sacramento-San Joaquin River Delta [Delta], Suisun Marsh, San Francisco Bay) during September-January; most went during December. Movements coincid- ed with start of hunting seasons and were related to pintail age, mass, capture location, study year, and weather. Among pintails with less than average mass, AHY individuals tended to leave the SJV earlier than HY individuals. Weekly distribution was similar among capture locations and years but a greater percentage of pintails radiotagged in Tulare Basin (south part of SJV) were known to have (10.3% vs. 0.9%) or probably (13.8% vs. 4.6%) wintered south of CCA than pintails radiotagged in northern SJV areas (i.e., Grassland Ecological Area [EA] and Mendota Wildlife Area [WA]). Also, a greater percentage of SJV pintails went to other CCA areas before hunting season in the drought year of 1991-1992 than later years (10% vs. 3-5%). The percent of radiotagged pintails from Grass- land EA known to have gone south of CCA also was greater during 1991-1992 than later years (2% vs. 0%), but both the known (19% vs. 4%) and probable (23% vs. 12%) percent from Tulare Basin that went south was greatest during 1993-1994, when availability of flooded fields there was lowest. The probability of pintails leaving the SJV was 57% (95% CI = 8-127%) greater on days with than without rain, and more movements per bird out of SJV occurred in years

  15. Diversity and ecological ranges of plant species from dry inter-Andean valleys

    DEFF Research Database (Denmark)

    Quintana, Catalina

    found on steep slopes and in ravines. These areas of original dry valley vegetation preserve many wild relatives of cultivated plants on the one hand and old lineages of other wild plant groups. Dry inter-Andean valleys (DIAVs) in Ecuador therefore makeup a biodiversity hot spot for both plants......Dry valleys in the American Andes and other mountains have provided excellent agricultural lands since millennia. Besides agriculture, wood extraction and the establishment of urban areas have diminished the native vegetation of these valleys. Consequently the original vegetation is now mostly...... and animals, but unfortunately only very few botanical studies have been carried out in these areas. This thesis intends to shed light on the vegetation of the Dry Ecuadorean Inter-Andean Valleys in four chapters, each with a different focus. 1) A review paper that summarizes all scientific knowledge...

  16. 75 FR 17756 - Blackstone River Valley National Heritage Corridor Commission: Notice of Meeting

    Science.gov (United States)

    2010-04-07

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Blackstone River Valley National Heritage..., United States Code, that a meeting of the John H. Chafee Blackstone River Valley National Heritage... the meeting to: Jan H. Reitsma, Executive Director, John H. Chafee, Blackstone River Valley National...

  17. West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2004

    Energy Technology Data Exchange (ETDEWEB)

    West Valley Nuclear Services Company (WVNSCO) and URS Group, Inc.

    2005-09-30

    Annual Site Environmental Report for the West Valley Demonstration Project (WVDP) for Calendar Year 2004. The report summarizes the environmental protection program at the West Valley Demonstration Project for CY 2004.

  18. West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2004

    International Nuclear Information System (INIS)

    2005-01-01

    Annual Site Environmental Report for the West Valley Demonstration Project (WVDP) for Calendar Year 2004. The report summarizes the environmental protection program at the West Valley Demonstration Project for CY 2004

  19. Environmental and economic effects of subsidence: Category 4, Project 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Viets, V.F.; Vaughan, C.K.; Harding, R.C.

    1979-05-01

    A list of more than 70 subsidence areas was screened to select those areas which seemed to have the best potential for providing reliable data. The screening process is described in an appendix. Nine areas were selected for detailed case studies to collect all available data on the environmental and economic effects of the subsidence. Available information from the subsidence areas not selected as case studies was tabulated for each area and is included in an appendix. The nine case study areas are: Arizona; San Joaquin Valley, California; Baldwin Hills, California; Santa Clara Valley, California; Wilmington, California; Las Vegas Valley, Nevada; Houston-Galveston area, Texas; Mexico City, Mexico; and Wairakei, New Zealand. (MHR)

  20. Mexico tornado climatology

    Directory of Open Access Journals (Sweden)

    Manuel Macías Medrano

    2013-07-01

    Full Text Available A brief introduction on some features of tornado database in Mexico is exposed showing its substantive criteria. We resent a brief analysis about main Mexican tornadoes´ characteristics, based on data collected between 2000 to 2010, talking about spatial and temporal expressions (historical, seasonal and horary in order to show the importance of it destruction capacity and also the people´s vulnerability in Mexico.

  1. Infill of tunnel valleys associated with landward‐flowing ice sheets

    DEFF Research Database (Denmark)

    Moreau, Julien; Huuse, Mads

    2014-01-01

    The southern termination of the Middle and Late Pleistocene Scandinavian ice sheets was repeatedly located in the southern North Sea (sNS) and adjacent, north-sloping land areas. Giant meltwater-excavated valleys (tunnel valleys) formed at the southern termination of the ice sheets and contain...

  2. Yes… Mexico is a racist country

    DEFF Research Database (Denmark)

    Carrales, Juan Carlos Finck

    2017-01-01

    According to recent official statistics, in Mexico there is a relation between people’s privileges and their skin color: The lighter, the more privilege. However, social exclusion by racist practices in Mexico has been common practically since its Spanish conquest between 1519 and 1521, in which...... privileges where absorbed and monopolized by European settlers in Mexico (Spanish people: peninsulares) and their descendants (creole: criollos). As a consequence, currently in Mexico, the color of skin affects people’s economic and political privileges and powers in individual and social levels related...

  3. Glacial geology of the upper Wairau Valley, Marlborough, New Zealand

    International Nuclear Information System (INIS)

    McCalpin, J.P.

    1992-01-01

    Late Pleistocene glaciers in the upper Wairau Valley deposited four groups of moraines inferred to represent one Waimean ice advance, two Otiran ice advances, and an advance of early Aranuian age. The Waimean and early Otiran glaciers advanced into Tarndale Valley, deposited terminal moraines, and shed outwash down both the Alma River and Travellers Valley. The middle Otiran glacier terminated in northern Tarndale Valley and shed outwash from the southern part of its terminus down the Alma River. The north side of the terminus abutted a large ice-dammed lake in the Wairau Gorge, and fan-deltas graded to an old shore level at an elevation of 1040 m. Well-preserved moraines at the mouths of four glaciated tributaries may be middle Otiran recessional, or late Otiran terminal moraines. The latest ice advance extended 11 km down the upper Wairau Valley and deposited a subdued moraine at Island Gully. The composite chronology of the latest glacial advance based on 10 radiocarbon ages suggests it occurred between about 9.5 and 10.2 ka. This age span is similar to that of early Aranuian glacial advances dated by other workers in the Southern Alps, and may reflect Younger Dryas cooling. (author). 22 refs., 10 figs., 3 tabs

  4. History of nonnative Monk Parakeets in Mexico.

    Science.gov (United States)

    Hobson, Elizabeth A; Smith-Vidaurre, Grace; Salinas-Melgoza, Alejandro

    2017-01-01

    Nonnative Monk Parakeets have been reported in increasing numbers across many cities in Mexico, and were formally classified as an invasive species in Mexico in late 2016. However, there has not been a large-scale attempt to determine how international pet trade and national and international governmental regulations have played a part in colonization, and when the species appeared in different areas. We describe the changes in regulations that led the international pet trade market to shift to Mexico, then used international trade data to determine how many parakeets were commercially imported each year and where those individuals originated. We also quantified the recent increases in Monk Parakeet (Myiopsitta monachus) sightings in Mexico in both the scientific literature and in citizen science reports. We describe the timeline of increased reports to understand the history of nonnative Monk Parakeets in Mexico. As in other areas where the species has colonized, the main mode of transport is through the international pet trade. Over half a million Monk Parakeets were commercially imported to Mexico during 2000-2015, with the majority of importation (90%) occurring in 2008-2014, and almost all (98%) were imported from Uruguay. The earliest record of a free-flying Monk Parakeet was observed during 1994-1995 in Mexico City, but sightings of the parakeets did not become geographically widespread in either the scientific literature or citizen science databases until 2012-2015. By 2015, parakeets had been reported in 97 cities in Mexico. Mexico City has consistently seen steep increases in reporting since this species was first reported in Mexico. Here we find that both national and international legal regulations and health concerns drove a rise and fall in Monk Parakeet pet trade importations, shortly followed by widespread sightings of feral parakeets across Mexico. Further monitoring of introduced Monk Parakeet populations in Mexico is needed to understand the

  5. Makran Mountain Range, Indus River Valley, Pakistan, India

    Science.gov (United States)

    1984-01-01

    The enormous geologic pressures exerted by continental drift can be very well illustrated by the long northward curving parallel folded mountain ridges and valleys of the coastal Makran Range of Pakistan (27.0N, 66.0E). As a result of the collision of the northward bound Indian sub-continent into the Asian Continent, the east/west parallel range has been bent in a great northward arc and forming the Indus River valley at the interface of the collision.

  6. New Mexico Property Tax Districts

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This layer represents boundaries for New Mexico tax district "OUT" categories and incorporated/municipal "IN" categories as identified on the "Certificate of Tax...

  7. Landform Evolution of the Zanskar Valley, Ladakh Himalaya.

    Science.gov (United States)

    Chahal, P.; Kumar, A.; Sharma, P.; Sundriyal, Y.; Srivastava, P.

    2017-12-01

    Zanskar River flow from south-west to north-east, perpendicularly through Higher Himalayan crystalline sequences, Tethyan sedimentary sequences, and Indus Molasses; and finally merge with the Indus River at Nimu. Geologically, the Indus valley is bounded by Ladakh Batholith in the north and highly folded and thrusted Zanskar mountain ranges in the south. Sedimentary sequences of Zanskar ranges are largely of continental origin, which were uplifted and deformed via several north verging thrusts, where Zanskar counter thrust, Choksti and Indus-Bazgo thrusts are important thrust zone, and there is atleast 36 km of crustal shortening in the Zanskar section which continued from middle Miocene to the late Pleistocene. This shortening is accommodated mainly by north or north-east directed Zanskar backthrusts. Two major tributaries of Zanskar: Tsrapchu and Doda, flow in the headwaters, along the strike of South Tibetan Detachment System (STDs), an east-west trending regional fault. The present study incorporate field sedimentology, geomorphology and chronology of landform associated with Zanskar valley. In the upper Zanskar, alluvial fan, valley fill and strath terraces configured the major landforms with paleo-lake deposits­­­ in the area between the fans. The lower catchment, at the confluence of Zanskar and Indus rivers, exhibit mainly valley fill terraces and strath terraces. Chronology suggests diachronous aggradation in the upper and lower Zanskar catchments. In the upper Zanskar large scale valley aggradation took place with simultaneously fan progradation and flooding events from 45-15 ka. Luminescence chronology of the lower Zanskar indicates aggradation from 145-55 ka and 18-12 ka. The two aggradation basins are separated by a deep V-shaped gorge which is approximately 60 km long. The longitudinal profile of the Zanskar River shows several local convexities marking knick point zone, which suggests tectonically controlled topography.

  8. Transport of regional pollutants through a remote trans-Himalayan valley in Nepal

    Directory of Open Access Journals (Sweden)

    S. Dhungel

    2018-01-01

    Full Text Available Anthropogenic emissions from the combustion of fossil fuels and biomass in Asia have increased in recent years. High concentrations of reactive trace gases and light-absorbing and light-scattering particles from these sources form persistent haze layers, also known as atmospheric brown clouds, over the Indo–Gangetic plains (IGP from December through early June. Models and satellite imagery suggest that strong wind systems within deep Himalayan valleys are major pathways by which pollutants from the IGP are transported to the higher Himalaya. However, observational evidence of the transport of polluted air masses through Himalayan valleys has been lacking to date. To evaluate this pathway, we measured black carbon (BC, ozone (O3, and associated meteorological conditions within the Kali Gandaki Valley (KGV, Nepal, from January 2013 to July 2015. BC and O3 varied over both diurnal and seasonal cycles. Relative to nighttime, mean BC and O3 concentrations within the valley were higher during daytime when the up-valley flow (average velocity of 17 m s−1 dominated. BC and O3 concentrations also varied seasonally with minima during the monsoon season (July to September. Concentrations of both species subsequently increased post-monsoon and peaked during March to May. Average concentrations for O3 during the seasonally representative months of April, August, and November were 41.7, 24.5, and 29.4 ppbv, respectively, while the corresponding BC concentrations were 1.17, 0.24, and 1.01 µg m−3, respectively. Up-valley fluxes of BC were significantly greater than down-valley fluxes during all seasons. In addition, frequent episodes of BC concentrations 2–3 times higher than average persisted from several days to a week during non-monsoon months. Our observations of increases in BC concentration and fluxes in the valley, particularly during pre-monsoon, provide evidence that trans-Himalayan valleys are important conduits for transport of

  9. Transport of regional pollutants through a remote trans-Himalayan valley in Nepal

    Science.gov (United States)

    Dhungel, Shradda; Kathayat, Bhogendra; Mahata, Khadak; Panday, Arnico

    2018-01-01

    Anthropogenic emissions from the combustion of fossil fuels and biomass in Asia have increased in recent years. High concentrations of reactive trace gases and light-absorbing and light-scattering particles from these sources form persistent haze layers, also known as atmospheric brown clouds, over the Indo-Gangetic plains (IGP) from December through early June. Models and satellite imagery suggest that strong wind systems within deep Himalayan valleys are major pathways by which pollutants from the IGP are transported to the higher Himalaya. However, observational evidence of the transport of polluted air masses through Himalayan valleys has been lacking to date. To evaluate this pathway, we measured black carbon (BC), ozone (O3), and associated meteorological conditions within the Kali Gandaki Valley (KGV), Nepal, from January 2013 to July 2015. BC and O3 varied over both diurnal and seasonal cycles. Relative to nighttime, mean BC and O3 concentrations within the valley were higher during daytime when the up-valley flow (average velocity of 17 m s-1) dominated. BC and O3 concentrations also varied seasonally with minima during the monsoon season (July to September). Concentrations of both species subsequently increased post-monsoon and peaked during March to May. Average concentrations for O3 during the seasonally representative months of April, August, and November were 41.7, 24.5, and 29.4 ppbv, respectively, while the corresponding BC concentrations were 1.17, 0.24, and 1.01 µg m-3, respectively. Up-valley fluxes of BC were significantly greater than down-valley fluxes during all seasons. In addition, frequent episodes of BC concentrations 2-3 times higher than average persisted from several days to a week during non-monsoon months. Our observations of increases in BC concentration and fluxes in the valley, particularly during pre-monsoon, provide evidence that trans-Himalayan valleys are important conduits for transport of pollutants from the IGP to the

  10. Diversity of inland valleys and opportunities for agricultural development in Sierra Leone.

    Directory of Open Access Journals (Sweden)

    Elliott Ronald Dossou-Yovo

    Full Text Available Inland valleys are becoming increasingly important agricultural production areas for rural households in sub-Saharan Africa due to their relative high and secure water availability and soil fertility. In addition, inland valleys are important as water buffer and biodiversity hot spots and they provide local communities with forest, forage, and fishing resources. As different inland-valley ecosystem functions may conflict with agricultural objectives, indiscriminate development should be avoided. This study aims to analyze the diversity of inland valleys in Sierra Leone and to develop guidelines for more precise interventions. Land use, biophysical and socio-economic data were analyzed on 257 inland valleys using spatial and multivariate techniques. Five cluster groups of inland valleys were identified: (i semi-permanently flooded with high soil organic carbon (4.2% and moderate available phosphorus (10.2 ppm, mostly under natural vegetation; (ii semi-permanently flooded with low soil organic carbon (1.5% and very low available phosphorus (3.1 ppm, abandoned by farmers; (iii seasonally flooded with moderate soil organic carbon (3.1% and low available phosphorus (8.3 ppm, used for rainfed rice and off-season vegetables produced without fertilizer application for household consumption and market; (iv well drained with moderate soil organic carbon (3.8% and moderate available phosphorus (10.0 ppm, used for rainfed rice and off-season vegetables produced with fertilizer application for household consumption and market; and (v well drained with moderate soil organic carbon (3.6% and moderate available phosphorus (11 ppm, used for household consumption without fertilizer application. Soil organic carbon, available phosphorus, hydrological regime, physical accessibility and market opportunity were the major factors affecting agricultural intensification of inland valleys. Opening up the areas in which inland valleys occur through improved roads and

  11. Structural evolution of the east Sierra Valley system (Owens Valley and vicinity), California: a geologic and geophysical synthesis

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul; Blakely, Richard J.

    2013-01-01

    The tectonically active East Sierra Valley System (ESVS), which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm), which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3-3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  12. New Mexico Charter Schools Annual Report

    Science.gov (United States)

    New Mexico Public Education Department, 2013

    2013-01-01

    In 2011, the New Mexico legislature passed changes to the Charter School Act that provided more accountability for both charters and authorizers in New Mexico. As part of that law, the Public Education Department (PED) is asked to submit an annual report on the status of charter schools in New Mexico. This is the first report submitted under that…

  13. Clean Cities Award Winning Coalition: Coachella Valley

    Energy Technology Data Exchange (ETDEWEB)

    ICF Kaiser

    1999-05-20

    Southern California's Coachella Valley became a Clean Cities region in 1996. Since then, they've made great strides. SunLine Transit, the regional public transit provider, was the first transit provider to replace its entire fleet with compressed natural gas buses. They've also built the foundation for a nationally recognized model in the clean air movement, by partnering with Southern California Gas Company to install a refueling station and developing a curriculum for AFV maintenance with the College of the Desert. Today the valley is home to more than 275 AFVs and 15 refueling stations.

  14. Some Environmental Issues of Inland Valleys: A Case Study | Asiam ...

    African Journals Online (AJOL)

    The study concluded that inland valleys can be real environmental liability because produce from such valleys can be polluted and hence can be a source of social conflict particularly when they fringe mineral concessions as the adverse impacts could be unfortunately attributed to mining activity and similar land uses.

  15. Parking Space Occupancy at Rail Stations in Klang Valley

    Directory of Open Access Journals (Sweden)

    Ho Phooi Wai

    2017-01-01

    Full Text Available The development of Klang Valley Integrated Rapid Transit system in Klang Valley, Malaysia has been quickly gaining momentum during the recent years. There will be two new MRT lines (MRT Line 1 and MRT Line 2 and one new LRT line (LRT Line 3 extended from the current integrated rail transit system by year 2020 with more than 90 new rail stations. With the substantial addition of potential rail passengers, there are doubts whether the existing Park and Ride facilities in Klang Valley are able to accommodate the future parking space demand at rail stations. This research studies the parking occupancy at various Park and Ride facilities in Klang Valley namely Taman Jaya, Asia Jaya, Taman Paramount, Taman Bahagia and Kelana Jaya by applying the non-conventional method utilizing Google Earth imageries. Results showed that the parking occupancy rate at these LRT stations were 100% or more before the commencement of LRT extension (Kelana Jaya and Ampang Lines in 2016 and in the range of 36% to 100% after the commencement of LRT extension due to the additionally built car parks and changes in parking pattern with dispersed passenger traffic.

  16. Martian channels and valleys - Their characteristics, distribution, and age

    Science.gov (United States)

    Carr, M. H.; Clow, G. D.

    1981-01-01

    The distribution and ages of Martian channels and valleys, which are generally believed to have been cut by running water, are examined with particular emphasis on the small branching networks referred to as runoff channels or valley networks. Valleys at latitudes from 65 deg S to 65 deg N were surveyed on Viking images at resolutions between 125 and 300 m. Almost all of the valleys are found in the old cratered terrain, in areas characterized by high elevations, low albedos and low violet/red ratios. The networks are deduced to have formed early in the history of the planet, with a formation rate declining rapidly shortly after the decline of the cratering rate 3.9 billion years ago. Two types of outflow channels are distinguished: unconfined, in which broad swaths of terrain are scoured, and confined, in which flow is restricted to discrete channels. Both types start at local sources, and have formed episodically throughout Martian history. Fretted channels, found mainly in two latitude belts characterized by relatively rapid erosion along escarpments, are explained by the lateral enlargement of other channels by mass wasting.

  17. Reporting on nuclear power: the Tennessee Valley case

    International Nuclear Information System (INIS)

    Shapley, D.

    1977-01-01

    The Tennessee Valley Authority (TVA), by deciding to have 90 percent of its new generating capacity nuclear, has made the valley a testing ground for civilian nuclear power, but valley newspapers have not provided consumers with enough information on either the pros or cons. A 1975 Browns Ferry plant fire, the most serious in the history of the civilian nuclear industry, prompted some nuclear critics to question TVA's competence to plan and manage the program. Newspapers carried wire-service stories of the fire, while their editorials gave strong support to TVA and the effort to reopen the plant. Valley newspapers have traditionally favored TVA as a powerful economic and political force which has brought many benefits. Local pride in the Oak Ridge Laboratory and plant facilities and the Federal fast-breeder reactor project headquarters also enhanced the positive attitude of the press, which tended to report details but not question nuclear safety or TVA ability. Newspapers have also failed to question TVA's claims that rates will decline as nuclear plants begin operating. A review of relevant news stories during the 1975--1976 period addresses the press coverage and notes its failure to question whether power demands justify TVA's plant construction program. Knowledgeable consultants are available to provide information on the issues, while editors are advised to give comprehensive, critical coverage and avoid promotion

  18. The electric energy and the environment in Mexico. Volume 3; Energia electrica y medio ambiente en Mexico. Volumen 3

    Energy Technology Data Exchange (ETDEWEB)

    Quintanilla Martinez, Juan [eds.] [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico)

    1997-12-31

    This document is the third one of three volumes of the 1. Seminar on the Current Conditions and Perspectives of the Electric Sector in Mexico, organized by the Programa Universitario de Energia and the Instituto de Investigaciones Economicas (University Program of Energy and the Institute of Economic Research), both of them agencies of the Universidad Autonoma de Mexico (UNAM). The titles of the three volumes are the following: Volume 1.- The opening of the Mexican Electric Sector to foreign investment. Volume 2.- Concrete innovation and technological learning experiences at the Luz y Fuerza del Centro enterprise. Volume 3.- The Electric Energy and the Environment in Mexico. This third volume covers the following subjects: Hydroelectricity, land use and water managing; the electric generation in Mexico and its environmental impact, the nuclear electricity and the handling of radioactive materials; the exposure to electromagnetic fields and its association with children`s leukemia; the energy in Mexico and the sustainable development; potential of electricity generation in large scale with wind power in Mexico; towards a scheme of distributed electric power generation with non-conventional energies and renewable energy sources in Mexico in the 21Century. These documents were elaborated by specialists of the electric sector, from the sector itself as well as from private and public academic entities [Espanol] Este documento constituye el tercero de tres volumenes del Primer Seminario sobre Situacion y Perspectivas del Sector Electrico en Mexico, organizado por el Programa Universitario de Energia y el Instituto de Investigaciones Economicas, ambas dependencias de la Universidad Nacional Autonoma de Mexico (UNAM). Los titulos de los tres volumenes son los siguientes: volumen 1: La apertura externa del sector electrico mexicano, volumen 2: Experiencias concretas de innovacion y aprendizaje tecnologico en la empresa Luz y Fuerza del Centro, volumen 3: Energia electrica

  19. HSIP Hospitals in New Mexico

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Hospitals in New Mexico The term "hospital" ... means an institution which- (1) is primarily engaged in providing, by or under the supervision of physicians, to...

  20. Decision analysis framing study; in-valley drainage management strategies for the western San Joaquin Valley, California

    Science.gov (United States)

    Presser, Theresa S.; Jenni, Karen E.; Nieman, Timothy; Coleman, James

    2010-01-01

    Constraints on drainage management in the western San Joaquin Valley and implications of proposed approaches to management were recently evaluated by the U.S. Geological Survey (USGS). The USGS found that a significant amount of data for relevant technical issues was available and that a structured, analytical decision support tool could help optimize combinations of specific in-valley drainage management strategies, address uncertainties, and document underlying data analysis for future use. To follow-up on USGS's technical analysis and to help define a scientific basis for decisionmaking in implementing in-valley drainage management strategies, this report describes the first step (that is, a framing study) in a Decision Analysis process. In general, a Decision Analysis process includes four steps: (1) problem framing to establish the scope of the decision problem(s) and a set of fundamental objectives to evaluate potential solutions, (2) generation of strategies to address identified decision problem(s), (3) identification of uncertainties and their relationships, and (4) construction of a decision support model. Participation in such a systematic approach can help to promote consensus and to build a record of qualified supporting data for planning and implementation. In December 2008, a Decision Analysis framing study was initiated with a series of meetings designed to obtain preliminary input from key stakeholder groups on the scope of decisions relevant to drainage management that were of interest to them, and on the fundamental objectives each group considered relevant to those decisions. Two key findings of this framing study are: (1) participating stakeholders have many drainage management objectives in common; and (2) understanding the links between drainage management and water management is necessary both for sound science-based decisionmaking and for resolving stakeholder differences about the value of proposed drainage management solutions. Citing

  1. Studies through EDXRF of pre hispanic objects of the archaeological zone of Cholula, Puebla, Mexico; Estudios mediante EDXRF de objetos prehispanicos de la zona arqueologica de Cholula, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Torres H, J.; Navarrete M, Z. [INAOP, 72840 Tonantzintla, Puebla (Mexico)

    2005-07-01

    In the valley of Puebla-Tlaxcala in Mexico flourished a culture, as great as the Teotihuacana, the Cholulteca, between the years 0-800. The product most known of this culture was the ceramic, famous by its colours; however, there was another important activity where they left master pieces, the mural painting. The mural 'Los Bebedores' is probably unique in its type. The technique used to paint it is not defined, but it was very similar to that known as 'al fresco'. This mural is inside of the great pyramid of Cholula and present damage due to its age and the different attempt to restore it. In this work we present the results obtained using a portable system of Energy-Dispersive X-Ray Fluorescence (EDXRF) to characterize the chemical composition of the polychromatic ceramic and the pigments, used in the mural painting, of Cholula. We describe the problems associated to the characterization of composition of the dyes used in the mural painting, due mainly to the thin layers of the pigments of this type of samples. (Author)

  2. Evaluation of geothermal potential of Rio Grande rift and Basin and Range province, New Mexico. Final technical report, January 1, 1977-May 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Callender, J.F.

    1985-04-01

    A study was made of the geological, geochemical and geophysical characteristics of potential geothermal areas in the Rio Grande rift and Basin and Range province of New Mexico. Both regional and site-specific information is presented. Data was collected by: (1) reconnaissance and detailed geologic mapping, emphasizing Neogene stratigraphy and structure; (2) petrologic studies of Neogene igneous rocks; (3) radiometric age-dating; (4) geochemical surveying, including regional and site-specific water chemistry, stable isotopic analyses of thermal waters, whole-rock and mineral isotopic studies, and whole-rock chemical analyses; and (5) detailed geophysical surveys, using electrical, gravity and magnetic techniques, with electrical resistivity playing a major role. Regional geochemical water studies were conducted for the whole state. Integrated site-specific studies included the Animas Valley, Las Cruces area (Radium Springs and Las Alturas Estates), Truth or Consequences region, the Albuquerque basin, the San Ysidro area, and the Abiquiu-Ojo Caliente region. The Animas Valley and Las Cruces areas have the most significant geothermal potential of the areas studied. The Truth or Consequences and Albuquerque areas need further study. The San Ysidro and Abiquiu-Ojo Caliente regions have less significant geothermal potential. 78 figs., 16 tabs.

  3. BPA/Lower Valley transmission project. Final environmental impact statement

    International Nuclear Information System (INIS)

    1998-06-01

    Bonneville Power Administration and Lower Valley Power and Light, Inc. propose to solve a voltage stability problem in the Jackson and Afton, Wyoming areas. Lower Valley buys electricity from BPA and then supplies it to the residences and businesses of the Jackson and Afton, Wyoming areas. BPA is considering five alternatives. For the Agency Proposed Action, BPA and Lower Valley would construct a new 115-kV line from BPA's Swan Valley Substation near Swan Valley in Bonneville County, Idaho about 58 km (36 miles) east to BPA's Teton Substation near Jackson in Teton County, Wyoming. The new line would be next to an existing 115-kV line. The Single-Circuit Line Alternative has all the components of the Agency Proposed Action except that the entire line would be supported by single-circuit wood pole H-frame structures. the Short Line Alternative has all the components of the Single-Circuit Line Alternative except it would only be half as long. BPA would also construct a new switching station near the existing right-of-way, west or north of Targhee Tap. Targhee Tap would then be removed. For the Static Var Compensation Alternative, BPA would install a Static Var Compensator (SVC) at Teton or Jackson Substation. An SVC is a group of electrical equipment placed at a substation to help control voltage on a transmission system. The No Action Alternative assumes that no new transmission line is built, and no other equipment is added to the transmission system

  4. Vitrification facility at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    DesCamp, V.A.; McMahon, C.L.

    1996-07-01

    This report is a description of the West Valley Demonstration Project's vitrification facilities from the establishment of the West Valley, NY site as a federal and state cooperative project to the completion of all activities necessary to begin solidification of radioactive waste into glass by vitrification. Topics discussed in this report include the Project's background, high-level radioactive waste consolidation, vitrification process and component testing, facilities design and construction, waste/glass recipe development, integrated facility testing, and readiness activities for radioactive waste processing

  5. Geomorphological characteristics of increased landslide activity in the Gudbrandsdalen valley, Norway

    Science.gov (United States)

    Heyerdahl, Håkon; Høydal, Øyvind

    2016-04-01

    The Gudbrandsdalen valley in Eastern Norway lies in a region where annual precipitation is generally low (down to 300 mm/year). The landslide activity has consequently historically been low, although the lower part of the valley sides generally is draped with thick layers of Quaternary deposits, primarily of glacial or glaciofluvial origin. The perception of natural hazards in the valley was previously primarily connected to flooding in the main river in the valley bottom during early summer, due to large discharges resulting from snowmelt in the mountainous regions west and east of the valley. However, several high-intensity events have changed the image of the region. Starting with a localized, but intense, landslide event in the Northern part of the valley in year 2008, two larger events covering almost the entire valley occurred in the years 2011 and 2013. A high number of landslides was triggered in all these events, including many flash floods and debris flows/debris slides in small and steep tributary rivers along the valley slopes. Landslide triggering covers different release mechanisms: In 2008, landslides were triggered without precipitation in not-frozen soil deposits without snow cover in the lower part of the valley. Groundwater flow through the permeable bedrock ("Otta schist") resulting from snow-melt in the elevated mountainous areas caused landslide triggering due to positive pore-water pressures forming at the bedrock surface below soil deposits, or at depressions in the terrain. Subsequent rainfall resulted in even more landslides being released. In later events (years 2011 and 2013) many landslides were caused by surface water taking new paths downslope, often due to man-made changes in existing waterways (typically poorly planned drainage solutions or new roads). Relatively small discharges in slopes with unconsolidated and easily erodible glacial deposits (typically lateral moraine) in many cases lead to small initial slides that down

  6. Rift Valley fever potential mosquito vectors and their infection status ...

    African Journals Online (AJOL)

    Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease. Rift Valley fever virus (RVFV) has been isolated from more than 40 species of mosquitoes from eight genera. This study was conducted to determine the abundance of potential mosquito vectors and their RVFV infection status in Ngorongoro ...

  7. Hydrogeologic Framework and Ground Water in Basin-Fill Deposits of the Diamond Valley Flow System, Central Nevada

    Science.gov (United States)

    Tumbusch, Mary L.; Plume, Russell W.

    2006-01-01

    The Diamond Valley flow system, an area of about 3,120 square miles in central Nevada, consists of five hydrographic areas: Monitor, Antelope, Kobeh, and Diamond Valleys and Stevens Basin. Although these five areas are in a remote part of Nevada, local government officials and citizens are concerned that the water resources of the flow system eventually could be further developed for irrigation or mining purposes or potentially for municipal use outside the study area. In order to better understand the flow system, the U.S. Geological Survey in cooperation with Eureka, Lander, and Nye Counties and the Nevada Division of Water Resources, is conducting a multi-phase study of the flow system. The principal aquifers of the Diamond Valley flow system are in basin-fill deposits that occupy structural basins comprised of carbonate rocks, siliciclastic sedimentary rocks, igneous intrusive rocks, and volcanic rocks. Carbonate rocks also function as aquifers, but their extent and interconnections with basin-fill aquifers are poorly understood. Ground-water flow in southern Monitor Valley is from the valley margins toward the valley axis and then northward to a large area of discharge by evapotranspiration (ET) that is formed south of a group of unnamed hills near the center of the valley. Ground-water flow from northern Monitor Valley, Antelope Valley, and northern and western parts of Kobeh Valley converges to an area of ground-water discharge by ET in central and eastern Kobeh Valley. Prior to irrigation development in the 1960s, ground-water flow in Diamond Valley was from valley margins toward the valley axis and then northward to a large discharge area at the north end of the valley. Stevens Basin is a small upland basin with internal drainage and is not connected with other parts of the flow system. After 40 years of irrigation pumping, a large area of ground-water decline has developed in southern Diamond Valley around the irrigated area. In this part of Diamond

  8. Groundwater budgets for Detrital, Hualapai, and Sacramento Valleys, Mohave County, Arizona, 2007-08

    Science.gov (United States)

    Garner, Bradley D.; Truini, Margot

    2011-01-01

    The United States Geological Survey, in cooperation with the Arizona Department of Water Resources, initiated an investigation of the hydrogeology and water resources of Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona in 2005, and this report is part of that investigation. Water budgets were developed for Detrital, Hualapai, and Sacramento Valleys to provide a generalized understanding of the groundwater systems in this rural area that has shown some evidence of human-induced water-level declines. The valleys are within the Basin and Range physiographic province and consist of thick sequences of permeable alluvial sediment deposited into basins bounded by relatively less permeable igneous and metamorphic rocks. Long-term natural recharge rates (1940-2008) for the alluvial aquifers were estimated to be 1,400 acre-feet per year (acre-ft/yr) for Detrital Valley, 5,700 acre-ft/yr for Hualapai Valley, and 6,000 acre-ft/yr for Sacramento Valley. Natural discharge rates were assumed to be equal to natural recharge rates, on the basis of the assumption that all groundwater withdrawals to date have obtained water from groundwater storage. Groundwater withdrawals (2007-08) for the alluvial aquifers were less than 300 acre-ft/yr for Detrital Valley, about 9,800 acre-ft/yr for Hualapai Valley, and about 4,500 acre-ft/yr for Sacramento Valley. Incidental recharge from leaking water-supply pipes, septic systems, and wastewater-treatment plants accounted for about 35 percent of total recharge (2007-08) across the study area. Natural recharge and discharge values in this study were 24-50 percent higher than values in most previously published studies. Water budgets present a spatially and temporally "lumped" view of water resources and incorporate many sources of uncertainty in this study area where only limited data presently are available.

  9. Diurnal cycle of air pollution in the Kathmandu Valley, Nepal: 2. Modeling results

    Science.gov (United States)

    Panday, Arnico K.; Prinn, Ronald G.; SchäR, Christoph

    2009-11-01

    After completing a 9-month field experiment studying air pollution and meteorology in the Kathmandu Valley, Nepal, we set up the mesoscale meteorological model MM5 to simulate the Kathmandu Valley's meteorology with a horizontal resolution of up to 1 km. After testing the model against available data, we used it to address specific questions to understand the factors that control the observed diurnal cycle of air pollution in this urban basin in the Himalayas. We studied the dynamics of the basin's nocturnal cold air pool, its dissipation in the morning, and the subsequent growth and decay of the mixed layer over the valley. During mornings, we found behavior common to large basins, with upslope flows and basin-center subsidence removing the nocturnal cold air pool. During afternoons the circulation in the Kathmandu Valley exhibited patterns common to plateaus, with cooler denser air originating over lower regions west of Kathmandu arriving through mountain passes and spreading across the basin floor, thereby reducing the mixed layer depth. We also examined the pathways of pollutant ventilation out of the valley. The bulk of the pollution ventilation takes place during the afternoon, when strong westerly winds blow in through the western passes of the valley, and the pollutants are rapidly carried out through passes on the east and south sides of the valley. In the evening, pollutants first accumulate near the surface, but then are lifted slightly when katabatic flows converge underneath. The elevated polluted layers are mixed back down in the morning, contributing to the morning pollution peak. Later in the morning a fraction of the valley's pollutants travels up the slopes of the valley rim mountains before the westerly winds begin.

  10. New Mexico State Forestry Districts

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset contains boundaries of the New Mexico Forestry Districts, plus the names of the district offices. It is in a vector digital structure digitized from a...

  11. PROFILE OF SOCIAL SERVICES FROM JIU VALLEY IN LIGHT PROFESSIONALS PERCEPTION. QUALITATIVE APPROACH

    Directory of Open Access Journals (Sweden)

    FELICIA ANDRIONI

    2012-10-01

    Full Text Available This study aims to analyse Jiu Valley social services profile using a qualitative perspective – focus grup analysis, by investigating perceptions of social services professionals from Jiu Valley, Hunedoara County, Romania. The qualitative methods of investigation, particularly important in achieving a comprehensive profile of social services from the Jiu Valley was to achieve a focused discussion sessions on social services. The following objectives were targeted by focus group: analysis of social professionals’ perception on social services from the Jiu Valley, Hunedoara County and identifying internal and external factors, to put their mark on the functioning of social services. Upon completion of discussions session focusing on social services in the Jiu Valley to conclude on the following aspects: social professionals perceive favorable development of social services in the Jiu Valley region in the period 2002-2008, and considering the dynamic development of these services is progressive. There are a number of elements which are seen by professionals as catalysts for the proper functioning and development of social services and factors inhibiting or blocking the functioning of these services.

  12. West Valley facility spent fuel handling, storage, and shipping experience

    International Nuclear Information System (INIS)

    Bailey, W.J.

    1990-11-01

    The result of a study on handling and shipping experience with spent fuel are described in this report. The study was performed by Pacific Northwest Laboratory (PNL) and was jointly sponsored by the US Department of Energy (DOE) and the Electric Power Research Institute (EPRI). The purpose of the study was to document the experience with handling and shipping of relatively old light-water reactor (LWR) fuel that has been in pool storage at the West Valley facility, which is at the Western New York Nuclear Service Center at West Valley, New York and operated by DOE. A subject of particular interest in the study was the behavior of corrosion product deposits (i.e., crud) deposits on spent LWR fuel after long-term pool storage; some evidence of crud loosening has been observed with fuel that was stored for extended periods at the West Valley facility and at other sites. Conclusions associated with the experience to date with old spent fuel that has been stored at the West Valley facility are presented. The conclusions are drawn from these subject areas: a general overview of the West Valley experience, handling of spent fuel, storing of spent fuel, rod consolidation, shipping of spent fuel, crud loosening, and visual inspection. A list of recommendations is provided. 61 refs., 4 figs., 5 tabs

  13. Geomorphic controls on Pleistocene knickpoint migration in Alpine valleys

    Science.gov (United States)

    Leith, Kerry; Fox, Matt; Moore, Jeffrey R.; Brosda, Julian; Krautblatter, Michael; Loew, Simon

    2014-05-01

    Recent insights into sub-glacial bedrock stress conditions suggest that the erosional efficiency of glaciers may reduce markedly following a major erosional cycle [Leith et al., 2013]. This implies that the formation of large glacial valleys within the Alps is likely to have occurred shortly after the onset of 100 ky glacial-interglacial cycles (at the mid-Pleistocene Revolution (MPR)). The majority of landscape change since this time may have therefore been driven by sub-aerial processes. This hypothesis is supported by observations of hillslope and channel morphology within Canton Valais (Switzerland), where major tributary valleys display a common morphology along their length, hinting at a shared geomorphic history. Glaciers currently occupy the headwaters of many catchments, while the upper reaches of rivers flow across extensive alluvial planes before abruptly transitioning to steep channels consisting of mixed bedrock and talus fan deposits. The rivers then converge to flow out over the alluvial plane of the Rhone Valley. Characteristically rough topographies within the region are suggested to mark the progressive transition from a glacial to fluvially-dominated landscape, and correlate well with steepened river channel sections determined from a 2.5 m resolution LiDAR DEM. We envisage a landscape in which ongoing tectonic uplift drives the emergence of Alpine bedrock through massive sedimentary valley infills (currently concentrated in the Rhone Valley), whose elevation is fixed by the consistent fluvial baselevel at Lake Geneva. As fluvial incision ceases at the onset of glaciation, continued uplift causes the formation of knickpoints at the former transition from bedrock to sedimentary infill. These knickpoints will then propagate upstream during subsequent interglacial periods. By investigating channel morphologies using an approach based on the steady-state form of the stream power equation, we can correlate steepened channel reaches (degraded

  14. Digital Geologic Map of New Mexico - Formations

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The geologic map was created in GSMAP at Socorro, New Mexico by Orin Anderson and Glen Jones and published as the Geologic Map of New Mexico 1:500,000 in GSMAP...

  15. Questa baseline and pre-mining ground-water quality investigation. 14. Interpretation of ground-water geochemistry in catchments other than the Straight Creek catchment, Red River Valley, Taos County, New Mexico, 2002-2003

    Science.gov (United States)

    Nordstrom, D. Kirk; McCleskey, R. Blaine; Hunt, Andrew G.; Naus, Cheryl A.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site but proximal analog. The Straight Creek catchment, chosen for this purpose, consists of the same Tertiary-age quartz-sericite-pyrite altered andesite and rhyolitic volcanics as the mine site. Straight Creek is about 5 kilometers east of the eastern boundary of the mine site. Both Straight Creek and the mine site are at approximately the same altitude, face south, and have the same climatic conditions. Thirteen wells in the proximal analog drainage catchment were sampled for ground-water chemistry. Eleven wells were installed for this study and two existing wells at the Advanced Waste-Water Treatment (AWWT) facility were included in this study. Eight wells were sampled outside the Straight Creek catchment: one each in the Hansen, Hottentot, and La Bobita debris fans, four in a well cluster in upper Capulin Canyon (three in alluvial deposits and one in bedrock), and an existing well at the U.S. Forest Service Questa Ranger Station in Red River alluvial deposits. Two surface waters from the Hansen Creek catchment and two from the Hottentot drainage catchment also were sampled for comparison to ground-water compositions. In this report, these samples are evaluated to determine if the geochemical interpretations from the Straight Creek ground-water geochemistry could be extended to other ground waters in the Red River Valley , including the mine site. Total-recoverable major cations and trace metals and dissolved major cations, selected trace metals, anions, alkalinity; and iron-redox species were determined for all surface- and ground-water samples. Rare-earth elements and low-level As, Bi, Mo, Rb, Re, Sb, Se, Te, Th, U, Tl, V, W, Y, and Zr were

  16. Rod consolidation at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    Bailey, W.J.

    1986-12-01

    A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab

  17. Salinity and resource management in the Hunter Valley

    Energy Technology Data Exchange (ETDEWEB)

    Creelman, R.A.; Cooke, R.; Simons, M. [RA Creelman & Associates (Australia)

    1995-08-01

    If excess water salinity is to be managed in the Hunter Valley, its causes and behaviour must be understood. Although Hunter Valley hydrology, hydrogeology and hydrogeochemistry require further study, there is now enough information available to begin the development of both temporal and spatial models as valley management tools. Currently the Department of Water Resources is developing a model known as Integrated Water Quality and Quantity Model (IQQM). IQQM which includes a salinity module is essentially a surface water simulation model. It wll enable testing of alternate management and operation policies such as the salinity property rights trading scheme recently introduced by the EPA to manage salt release from coal mines and power stations. An overview is presented of the progress made to date on the salinity module for IQQM, and an outline is given of the geological and hydrogeochemical concepts that have been assembled to support the salinity module of IQQM. 17 refs., 3 figs., 1 tab.

  18. The Uncanny Valley and Nonverbal Communication in Virtual Characters

    DEFF Research Database (Denmark)

    Tinwell, Angela; Grimshaw, Mark Nicholas; Abdel Nabi, Debbie

    2014-01-01

    This chapter provides an overview of a current research project investigating the Uncanny Valley phenomenon in realistic, human-like virtual characters. !e research methods used in this Work include a retrospective of both empirical studies and philosophical writings on the Uncanny. No other...... research has explored the notion that realistic, human-like, virtual characters are regarded less favorably due to a perceived diminished degree of responsiveness in facial expression, specifically, nonverbal communication (NVC) in the upper face region. So far, this research project has provided the first...... empirical evidence to test the Uncanny Valley phenomenon in the domain of animated video game characters with speech, as opposed to just still, unresponsive images, as used in previous studies. Based on the results of these experiments, a conceptual framework of the Uncanny Valley in virtual characters has...

  19. Generation of valley-polarized electron beam in bilayer graphene

    International Nuclear Information System (INIS)

    Park, Changsoo

    2015-01-01

    We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents

  20. Generation of valley-polarized electron beam in bilayer graphene

    Science.gov (United States)

    Park, Changsoo

    2015-12-01

    We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents.

  1. Vertical ozone transport in the Alps (VOTALP): the valley experiment 1996

    Energy Technology Data Exchange (ETDEWEB)

    Furger, M; Dommen, J; Graber, W K; Prevot, A; Poggio, L; Andreani, S; Keller, J; Portmann, W; Buerki, D; Erne, R; Richter, R; Tinguely, M [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The EU project VOTALP started its valley campaign in the summer of 1996 in the Mesolcina valley. The influence of thermal circulations on ozone concentrations and on the exchange of ozone and its photochemical precursors between the valley atmosphere and the free troposphere above was the main focus of the study. PSI has participated with various measurement systems (conventional meteorological surface stations, radiosondes, scidar/DOAS systems, chemical analysers). An overview of PSI`s activities in the field campaign is given, and some preliminary results are presented. (author) 1 fig., 2 tabs., 2 refs.

  2. 75 FR 70020 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2010-11-16

    ... office on Central Valley Project water conservation best management practices that shall ``* * * develop... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior ACTION: Notice of Availability. SUMMARY: The...

  3. 76 FR 12756 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2011-03-08

    ... office on Central Valley Project water conservation best management practices that shall ``* * * develop... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

  4. 77 FR 64544 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2012-10-22

    ... Central Valley Project water conservation best management practices that shall ``develop criteria for... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

  5. 76 FR 18542 - Copper Valley Electric Association; Notice of Scoping Document 2 and Soliciting Scoping Comments...

    Science.gov (United States)

    2011-04-04

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley.... Applicant: Copper Valley Electric Association (Copper Valley) d. Name of Project: Allison Creek Project. e.... 791(a)-825(r). g. Applicant Contact: Robert A. Wilkinson, CEO, Copper Valley Electric Association, P.O...

  6. Diurnal and Nocturnal Pollination of Marginatocereus marginatus (Pachycereeae: Cactaceae) in Central Mexico

    Science.gov (United States)

    DAR, SALEEM; ARIZMENDI, Ma. del CORO; VALIENTE-BANUET, ALFONSO

    2006-01-01

    • Background and Aims Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. • Methods Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. • Key Results Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. • Conclusions Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico. PMID:16394025

  7. Electronic properties in a two-dimensional disordered electron liquid: Spin-valley interplay

    International Nuclear Information System (INIS)

    Burmistrov, I. S.; Chtchelkatchev, N. M.

    2008-01-01

    We report a detailed study of the influence of the spin and valley splittings on such physical observables of the two-dimensional disordered electron liquid as resistivity and spin and valley susceptibilities. We explain qualitatively the nonmonotonic dependence of the resistivity on temperature in the presence of a parallel magnetic field. In the presence of either spin or valley splitting we predict a temperature dependence of the resistivity with two maximum points

  8. Superior Valley Polarization and Coherence of 2s Excitons in Monolayer WSe_{2}.

    Science.gov (United States)

    Chen, Shao-Yu; Goldstein, Thomas; Tong, Jiayue; Taniguchi, Takashi; Watanabe, Kenji; Yan, Jun

    2018-01-26

    We report the experimental observation of 2s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2s exciton displays superior valley polarization and coherence than 1s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

  9. Superior Valley Polarization and Coherence of 2 s Excitons in Monolayer WSe2

    Science.gov (United States)

    Chen, Shao-Yu; Goldstein, Thomas; Tong, Jiayue; Taniguchi, Takashi; Watanabe, Kenji; Yan, Jun

    2018-01-01

    We report the experimental observation of 2 s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2 s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2 s exciton displays superior valley polarization and coherence than 1 s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

  10. 78 FR 21414 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2013-04-10

    ... Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The following Water Management Plans are available for review... establish and administer an office on Central Valley Project water conservation best management practices...

  11. 76 FR 54251 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2011-08-31

    ... and administer an office on Central Valley Project water conservation best management practices that... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

  12. 75 FR 38538 - Central Valley Project Improvement Act, Water Management Plans

    Science.gov (United States)

    2010-07-02

    ... to establish and administer an office on Central Valley Project water conservation best management... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

  13. Virgin Valley opal district, Humboldt County, Nevada

    Science.gov (United States)

    Staatz, Mortimer Hay; Bauer, Herman L.

    1951-01-01

    The Virgin Valley opal district, Humboldt County, Nevada, is near the Oregon-Nevada border in the Sheldon Game Refuge. Nineteen claims owned by Jack and Toni Crane were examined, sampled, and tested radiometrically for uranium. Numerous discontinuous layers of opal are interbedded with a gently-dipping series of vitric tuff and ash which is at least 300 ft thick. The tuff and ash are capped by a dark, vesicular basalt in the eastern part of the area and by a thin layer of terrace qravels in the area along the west side of Virgin Valley. Silicification of the ash and tuff has produced a rock that ranges from partly opalized rock that resembles silicified shale to completely altered rock that is entirely translucent, and consists of massive, brown and pale-green opal. Carnotite, the only identified uranium mineral, occurs as fracture coatings or fine layers in the opal; in places, no uranium minerals are visible in the radioactive opal. The opal layers are irregular in extent and thickness. The exposed length of the layers ranges from 8 to 1, 200 ft or more, and the thickness of the layers ranges from 0. 1 to 3. 9 ft. The uranium content of each opal layer, and of different parts of the same layer, differs widely. On the east side of Virgin Valley four of the seven observed opal layers, nos. 3, 4, 5, and 7, are more radioactive than the average; and the uranium content ranges from 0. 002 to 0. 12 percent. Two samples, taken 5 ft apart across opal layer no. 7, contained 0. 003 and 0. -049 percent uranium. On the west side of the valley only four of the fifteen observed opal layers, nos; 9, , 10, 14, and 15, are more radioactive than the average; and the uranium content ranges from 0. 004 to 0. 047 percent. Material of the highest grade was found in a small discontinuous layer of pale-green opal (no. 4) on the east side of Virgin Valley. The grade of this layer ranged from 0. 027 to 0. 12 percent uranium.

  14. 77 FR 42722 - Copper Valley Electric Association; Notice of Updated Environmental Analysis Preparation Schedule

    Science.gov (United States)

    2012-07-20

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley...: Original License Application. b. Project No.: 13124-002. c. Applicant: Copper Valley Electric Association (Copper Valley). d. Name of Project: Allison Creek Project. e. Location: On the south side of Port Valdez...

  15. Velocity barrier-controlled of spin-valley polarized transport in monolayer WSe2 junction

    Science.gov (United States)

    Qiu, Xuejun; Lv, Qiang; Cao, Zhenzhou

    2018-05-01

    In this work, we have theoretically investigated the influence of velocity barrier on the spin-valley polarized transport in monolayer (ML) WSe2 junction with a large spin-orbit coupling (SOC). Both the spin-valley resolved transmission probabilities and conductance are strong dependent on the velocity barrier, as the velocity barrier decreases to 0.06, a spin-valley polarization of exceeding 90% is observed, which is distinct from the ML MoS2 owing to incommensurable SOC. In addition, the spin-valley polarization is further increased above 95% in a ML WSe2 superlattice, in particular, it's found many extraordinary velocity barrier-dependent transport gaps for multiple barrier due to evanescent tunneling. Our results may open an avenue for the velocity barrier-controlled high-efficiency spin and valley polarizations in ML WSe2-based electronic devices.

  16. Interpretation of gravity profiles across the northern Oaxaca terrane, its boundaries and the Tehuacán Valley, southern Mexico

    Science.gov (United States)

    Campos-Enríquez, J. O.; Alatorre-Zamora, M. A.; Keppie, J. D.; Belmonte-Jiménez, S. I.; Ramón-Márquez, V. M.

    2014-12-01

    A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2.

  17. Ground water in Dale Valley, New York

    Science.gov (United States)

    Randall, Allan D.

    1979-01-01

    Dale Valley is a broad valley segment, enlarged by glacial erosion, at the headwaters of Little Tonawanda Creek near Warsaw , New York. A thin, shallow alluvial aquifer immediately underlies the valley floor but is little used. A deeper gravel aquifer, buried beneath many feet of lake deposits, is tapped by several industrial wells. A finite-difference digital model treated the deep aquifer as two-dimensional with recharge and discharge through a confining layer. It was calibrated by simulating (1) natural conditions, (2) an 18-day aquifer test, and (3) 91 days of well-field operation. Streamflow records and model simulations suggest that in moderately wet years such as 1974, a demand of 750 gallons per minute could be met by withdrawal from the creek and from the aquifer without excessive drawdown at production wells or existing domestic wells. With reasonable but unverified model adjustments to simulate an unusually dry year, the model predicts that a demand of 600 gallons per minute could be met from the same sources. Water high in chloride has migrated from bedrock into parts of the deep aquifer. Industrial pumpage, faults in the bedrock, and the natural flow system may be responsible. (Woodard-USGS)

  18. Increased body mass of ducks wintering in California's Central Valley

    Science.gov (United States)

    Fleskes, Joseph P.; Yee, Julie L.; Yarris, Gregory S.; Loughman, Daniel L.

    2016-01-01

    Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley Joint Venture conservation programs and changing agricultural practices; we modeled to ascertain whether body condition differed among waterfowl during these periods. Three dataset comparisons indicate that dabbling duck body mass was greater in 2006–2008 than earlier years and the increase was greater in the Sacramento Valley and Suisun Marsh than in the San Joaquin Valley, differed among species (mallard [Anas platyrhynchos], northern pintail [Anas acuta], America wigeon [Anas americana], green-winged teal [Anas crecca], and northern shoveler [Anas clypeata]), and was greater in ducks harvested late in the season. Change in body mass also varied by age–sex cohort and month for all 5 species and by September–January rainfall for all except green-winged teal. The random effect of year nested in period, and sometimes interacting with other factors, improved models in many cases. Results indicate that improved habitat conditions in the Central Valley have resulted in increased winter body mass of dabbling ducks, especially those that feed primarily on seeds, and this increase was greater in regions where area of post-harvest flooding of rice and other crops, and wetland area, has increased. Conservation programs that continue to promote post-harvest flooding and other agricultural practices that benefit wintering waterfowl and continue to restore and conserve wetlands would likely help maintain body condition of wintering dabbling ducks in the Central Valley of California.

  19. Meie mees Silicon Valleys / Kertu Ruus

    Index Scriptorium Estoniae

    Ruus, Kertu, 1977-

    2007-01-01

    Ilmunud ka: Delovõje Vedomosti 5. dets. lk. 4. Peaminister Andrus Ansip avas Eesti Ettevõtluse Sihtasutuse esinduse Silicon Valley pealinnas San Joses. Vt. samas: Ränioru kliima on tehnoloogiasõbralik; Andrus Viirg

  20. United States-Mexico cross-border health insurance initiatives: Salud Migrante and Medicare in Mexico.

    Science.gov (United States)

    Vargas Bustamante, Arturo; Laugesen, Miriam; Caban, Mabel; Rosenau, Pauline

    2012-01-01

    While U.S. health care reform will most likely reduce the overall number of uninsured Mexican-Americans, it does not address challenges related to health care coverage for undocumented Mexican immigrants, who will remain uninsured under the measures of the reform; documented low-income Mexican immigrants who have not met the five-year waiting period required for Medicaid benefits; or the growing number of retired U.S. citizens living in Mexico, who lack easy access to Medicare-supported services. This article reviews two promising binational initiatives that could help address these challenges-Salud Migrante and Medicare in Mexico; discusses their prospective applications within the context of U.S. health care reform; and identifies potential challenges to their implementation (legal, political, and regulatory), as well as the possible benefits, including coverage of uninsured Mexican immigrants, and their integration into the U.S. health care system (through Salud Migrante), and access to lower-cost Medicare-supported health care for U.S. retirees in Mexico (Medicare in Mexico).

  1. Coupled simulation of meteorological parameters and sound intensity in a narrow valley

    Energy Technology Data Exchange (ETDEWEB)

    Heimann, D. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Gross, G. [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

    1997-07-01

    A meteorological mesoscale model is used to simulate the inhomogeneous distribution of temperature and the appertaining development of thermal wind systems in a narrow two-dimensional valley during the course of a cloud-free day. A simple sound particle model takes up the simulated meteorological fields and calculates the propagation of noise which originates from a line source at one of the slopes of this valley. The coupled modeling system ensures consistency of topography, meteorological parameters and the sound field. The temporal behaviour of the sound intensity level across the valley is examined. It is only governed by the time-dependent meteorology. The results show remarkable variations of the sound intensity during the course of a day depending on the location in the valley. (orig.) 23 refs.

  2. Transport of particle pollution into the Maipo Valley: winter 2015 campaign results

    Science.gov (United States)

    Huneeus, Nicolás; Mazzeo, Andrea; Ordóñez, César; Donoso, Nicolás; Gallardo, Laura; Molina, Luisa; Moreno, Valeria; Muñoz, Ricardo; Orfanoz, Andrea; Vizcarra, Aldo

    2016-04-01

    Each winter, Santiago (33° 27'S, 70° 40'W) the capital of Chile with a population of about 7 million people, experiences episodes with particulate matter (PM) concentrations larger than allowed by Chilean environmental regulations. Transport and residential heating largely dominate emissions prior to and during these episodes. Important impact of black carbon (BC) on the cryosphere has been documented in other parts of the world associated with urban pollution. In order to explore if BC from Santiago has the potential to reach the Andean cryosphere during the aforementioned episodes, a one week-long campaign was conducted in Santiago and the Maipo Valley between 18th and 25th of July 2015 when the air quality conditions of the city reached twice the critical levels (pre-emergency in Chilean regulations). Measurements were carried out at three sites: downtown Santiago, the entrance of the valley (and outskirts of Santiago) and 12 km inside the Maipo Valley. At each of these sites both surface and vertically distributed measurements were conducted. A meteorological station measuring standard meteorological parameters and an E-Sampler measuring PM10 concentrations were installed at each site. In addition, a tethered balloon equipped with a sonde and a mini-aethalometer was used in each site to measure vertical profiles of standard meteorological parameters and BC concentrations, respectively. The tethered balloon was raised every three hours up to a maximum of 1000 meters above ground level, whenever meteorological conditions allowed. In general, the BC concentrations inside the valley, both at the surface and in the vertical, were dominated by emissions within the valley and BC was limited to shallow layers above the ground. However, on both days with critical air quality levels, winds blowing from the city and deeper BC layers were observed inside the valley. Furthermore, during these days observations at the entrance of the valley and those taken inside were

  3. 40 CFR 81.90 - Androscoggin Valley Interstate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Quality Control Region. 81.90 Section 81.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.90 Androscoggin Valley Interstate Air Quality Control Region. The Androscoggin Valley Interstate Air Quality Control Region (Maine-New Hampshire) consists of the territorial...

  4. Contributors to ozone episodes in three US/Mexico border twin-cities.

    Science.gov (United States)

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma.

  5. Fully Valley/spin polarized current and Fano factor through the Graphene/ferromagnetic silicene/Graphene junction

    Energy Technology Data Exchange (ETDEWEB)

    Rashidian, Zeinab; Rezaeipour, Saeid [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Hajati, Yaser [Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Lorestaniweiss, Zeinab, E-mail: rashidian1983z@gmail.com [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Ueda, Akiko [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba (Japan)

    2017-02-15

    In this work, we study the transport properties of Dirac fermions through the ferromagnetic silicene which is sandwiched between the Graphene leads (G/FS/G). Spin/valley conductance, spin/valley polarization, and also Fano factor are theoretically calculated using the Landauer-Buttiker formula. We find that the fully valley and spin polarized currents through the G/FS/G junction can be obtained by increasing the electric field strength and the length of ferromagnetic silicene region. Moreover, the valley polarization can be tuned from negative to positive values by changing the electric field. We find that the Fano factor also changes with the spin and valley polarization. Our findings of high controllability of the spin and valley transport in such a G/FS/G junction the potential of this junction for spin-valleytronics applications.

  6. Vegetation - San Felipe Valley [ds172

    Data.gov (United States)

    California Natural Resource Agency — This Vegetation Map of the San Felipe Valley Wildlife Area in San Diego County, California is based on vegetation samples collected in the field in 2002 and 2005 and...

  7. 2D Semiconductors for Valley-Polarized LEDs and Photodetectors

    Science.gov (United States)

    Yu, Ting

    The recently discovered two-dimensional (2D) semiconductors, such as transitional-metal-dichalcogenide monolayers, have aroused great interest due to the underlying quantum physics and the appealing optoelectronic applications like atomically thin light-emitting diodes (LEDs) and photodetectors. On the one hand, valley-polarized electroluminescence and photocurrent from such monolayers have not caused enough attention but highly demanded as building blocks for the new generation valleytronic applications. On the other hand, most reports on these devices are based on the mechanically exfoliated small samples. Considering real applications, a strategy which could offer mass-product and high compatibility to the current planar processes is greatly demanded. Large-area samples prepared by chemical vapour deposition (CVD) are perfect candidates towards such a goal. Here, we report electrically tunable valley-polarized electroluminescence and the selective spin-valley-coupled photocurrent in optoelectronic devices based on monolayer WS2 and MoS2 grown by CVD, exhibiting large electroluminescence and photocurrent dichroisms of 81% and 60%, respectively. The controllable valley polarization and emission components of the electroluminescence have been realized by varying electrical injection of carriers. For the observed helicity-dependent photocurrent, the circular photogalvanic effect at resonant excitations has been found to take the dominant responsibility.

  8. Esophageal cancer in north rift valley of western Kenya | Wakhisi ...

    African Journals Online (AJOL)

    Esophageal cancer in north rift valley of western Kenya. ... Our finding also contrast with an earlier reported study that indicated that Rift Valley is a low prevalence area for this type of cancer. The mean age ... This may lead to identification of molecular biomarkers to be used in future for the early detection of this neoplasm.

  9. Ethno-botanical study of medicinal plants of Paddar Valley of ...

    African Journals Online (AJOL)

    The Paddar Valley, historically known as Sapphire Valley situated in Kishtwar district, is a prime landmark in the Jammu region of J&K state and is known for its rich cultural and plant diversity because of diverse habitats such as rivers, streams, meadows and steep mountain slopes. The area is located in the dry temperate ...

  10. Evidence for strong Holocene earthquake(s) in the Wabash Valley seismic zone

    International Nuclear Information System (INIS)

    Obermeier, S.

    1991-01-01

    Many small and slightly damaging earthquakes have taken place in the region of the lower Wabash River Valley of Indiana and Illinois during the 200 years of historic record. Seismologists have long suspected the Wabash Valley seismic zone to be capable of producing earthquakes much stronger than the largest of record (m b 5.8). The seismic zone contains the poorly defined Wabash Valley fault zone and also appears to contain other vaguely defined faults at depths from which the strongest earthquakes presently originate. Faults near the surface are generally covered with thick alluvium in lowlands and a veneer of loess in uplands, which make direct observations of faults difficult. Partly because of this difficulty, a search for paleoliquefaction features was begun in 1990. Conclusions of the study are as follows: (1) an earthquake much stronger than any historic earthquake struck the lower Wabash Valley between 1,500 and 7,500 years ago; (2) the epicentral region of the prehistoric strong earthquake was the Wabash Valley seismic zone; (3) apparent sites have been located where 1811-12 earthquake accelerations can be bracketed

  11. Structural Evolution of the East Sierra Valley System (Owens Valley and Vicinity, California: A Geologic and Geophysical Synthesis

    Directory of Open Access Journals (Sweden)

    Richard J. Blakely

    2013-04-01

    Full Text Available The tectonically active East Sierra Valley System (ESVS, which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm, which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  12. Significance of Hemispheric Security for Mexico

    Science.gov (United States)

    2003-04-07

    La Seguridad Internacional, la Nueva Geopolitica Continental y Mexico ,” Seminario Internacional sobre Misiones de Paz, Seguridad y Defensa, Rio de...USAWC STRATEGY RESEARCH PROJECT SIGNIFICANCE OF HEMISPHERIC SECURITY FOR MEXICO by LTC Enrique Garcia Jaramillo Cavalry, Mexican Army COL Joseph R...xx-xx-2002 to xx-xx-2003 4. TITLE AND SUBTITLE Significance of Hemispheric Security for Mexico Unclassified 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  13. Episodic Late Holocene dune movements on the sand-sheet area, Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado, USA

    Science.gov (United States)

    Forman, S. L.; Spaeth, M.; Marín, L.; Pierson, J.; Gómez, J.; Bunch, F.; Valdez, A.

    2006-07-01

    The Great Sand Dunes National Park and Preserve (GSDNPP) in the San Luis Valley, Colorado, contains a variety of eolian landforms that reflect Holocene drought variability. The most spectacular is a dune mass banked against the Sangre de Cristo Mountains, which is fronted by an extensive sand sheet with stabilized parabolic dunes. Stratigraphic exposures of parabolic dunes and associated luminescence dating of quartz grains by single-aliquot regeneration (SAR) protocols indicate eolian deposition of unknown magnitude occurred ca. 1290-940, 715 ± 80, 320 ± 30, and 200-120 yr ago and in the 20th century. There are 11 drought intervals inferred from the tree-ring record in the past 1300 yr at GSDNPP potentially associated with dune movement, though only five eolian depositional events are currently recognized in the stratigraphic record. There is evidence for eolian transport associated with dune movement in the 13th century, which may coincide with the "Great Drought", a 26-yr-long dry interval identified in the tree ring record, and associated with migration of Anasazi people from the Four Corners areas to wetter areas in southern New Mexico. This nascent chronology indicates that the transport of eolian sand across San Luis Valley was episodic in the late Holocene with appreciable dune migration in the 8th, 10-13th, and 19th centuries, which ultimately nourished the dune mass against the Sangre de Cristo Mountains.

  14. Aburra Valley: Quo vadis?

    International Nuclear Information System (INIS)

    Hermelin, Michel

    2008-01-01

    These paper intents a brief description of the evolution that characterised natural risk prevention in the area surrounding the city of Medellin, Colombia, called the Aburra Valley. Both the lithological and structural composition of the Valle and its topographic and climatic conditions contribute to the abundance of destructive natural phenomena as earthquakes, slope movements, flash floods and, in a lower proportion, to floods. The population increase, which reaches now 3.5 millions inhabitants and the frequent occupation of sites exposed to natural hazards have resulted in numerous disasters. At present two entities called SIMPAD and DAPARD work on risk prevention, on city and department scale respectively. The amount of knowledge about physical environment is considered to be insufficient, together with regulations which should direct land use in accordance to restrictions related to natural hazards. Several seminars on this topic have already been carried out and the organisers of the present one, destined to commemorate the twentieth anniversary of the Villatina disaster, should make the decision to meet each two years. Furthermore, the creation of a permanent commission dedicated to study past events, to foster information broadcasting and to seek a better knowledge of the Aburra Valley, should be considered

  15. Electron spin resonance and spin-valley physics in a silicon double quantum dot.

    Science.gov (United States)

    Hao, Xiaojie; Ruskov, Rusko; Xiao, Ming; Tahan, Charles; Jiang, HongWen

    2014-05-14

    Silicon quantum dots are a leading approach for solid-state quantum bits. However, developing this technology is complicated by the multi-valley nature of silicon. Here we observe transport of individual electrons in a silicon CMOS-based double quantum dot under electron spin resonance. An anticrossing of the driven dot energy levels is observed when the Zeeman and valley splittings coincide. A detected anticrossing splitting of 60 MHz is interpreted as a direct measure of spin and valley mixing, facilitated by spin-orbit interaction in the presence of non-ideal interfaces. A lower bound of spin dephasing time of 63 ns is extracted. We also describe a possible experimental evidence of an unconventional spin-valley blockade, despite the assumption of non-ideal interfaces. This understanding of silicon spin-valley physics should enable better control and read-out techniques for the spin qubits in an all CMOS silicon approach.

  16. Cleanup criteria for the West Valley demonstration project

    International Nuclear Information System (INIS)

    Parrott, J.D.

    1999-01-01

    The US Nuclear Regulatory Commission (NRC) is prescribing decontamination and decommissioning (cleanup) criteria for the West Valley Demonstration Project and the West Valley, New York, site. The site is contaminated with various forms of residual radioactive contamination and contains a wide variety of radioactive waste. The NRC is planning to issue cleanup criteria for public comment in Fall 1999. Due to the complexity of the site, and the newness of NRC's cleanup criteria policy, applying NRC's cleanup criteria to this site will be an original regulatory undertaking. (author)

  17. Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators.

    Science.gov (United States)

    Ni, Xiang; Purtseladze, David; Smirnova, Daria A; Slobozhanyuk, Alexey; Alù, Andrea; Khanikaev, Alexander B

    2018-05-01

    Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage ( 1 - 3 ). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light ( 4 - 6 ). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom.

  18. Stratigraphy and uranium deposits, Lisbon Valley district, San Juan County, Utah

    International Nuclear Information System (INIS)

    Huber, G.C.

    1980-01-01

    Uranium occurrences are scattered throughout southeastern Utah in the lower sandstones of the Triassic Chinle Formation. The Lisbon Valley district, however, is the only area with uranium deposits of substantial size. The stratigraphy of the Lisbon Valley district was investigated to determine the nature of the relationship between the mineralized areas and the lower Chinle sandstones. The geochemistry of the Lisbon Valley uranium deposits indicates a possible district-wide zoning. Interpretation of the elemental zoning associated with individual ore bodies suggests that humates overtaken by a geochemical oxidation-reduction interface may have led to formation of the uranium deposits. Refs

  19. Meie ingel Silicon Valleys / Raigo Neudorf

    Index Scriptorium Estoniae

    Neudorf, Raigo

    2008-01-01

    Ettevõtluse Arendamise Sihtasutuse esinduse töölepanekust USAs Silicon Valleys räägib esinduse juht Andrus Viirg. Vt. ka: Eestlasi leidub San Franciscos omajagu; Muljetavaldav karjäär; USAga ammune tuttav

  20. Microbial terroir in Chilean valleys: Diversity of non-conventional yeast

    Directory of Open Access Journals (Sweden)

    Carla eJara

    2016-05-01

    Full Text Available In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30ºS and 36ºS was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product.

  1. Reconstruction of the MSRs in-situ at Beaver Valley

    International Nuclear Information System (INIS)

    Yarden, A.; Tam, C.W.; Deahna, S.T.; McFeaters, C.V.

    1992-01-01

    The Moisture Separator Reheaters (MSRs) have been problem components at Beaver Valley 1 pressurized water reactor since the plant started up 16 years ago, many of the problems encountered being widespread in the nuclear industry. In 1991, Duquesne Light rebuilt the Beaver Valley 1 MSRs and in 1992 did the same at unit 2. The reconstruction projects have proved cost effective with short payback times and significant improvements in station performance. (Author)

  2. Seismicity related to geothermal development in Dixie Valley, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Ryall, A.S.; Vetter, U.R.

    1982-07-08

    A ten-station seismic network was operated in and around the Dixie Valley area from January 1980 to November 1981; three of these stations are still in operation. Data from the Dixie Valley network were analyzed through 30 Jun 1981, and results of analysis were compared with analysis of somewhat larger events for the period 1970-1979. The seismic cycle in the Western Great Basic, the geologic structural setting, and the instrumentation are also described.

  3. EPA Region 1 - Map Layers for Valley ID Tool (Hosted Feature Service)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Valley Service Feature Layer hosts spatial data for EPA Region 1's Valley Identification Tool. These layers contain attribute information added by EPA R1 GIS...

  4. Use of stable isotopes in the investigation of the effects of wastewater reuse on groundwater in Mexico

    International Nuclear Information System (INIS)

    Chilton, P.J.; Stuart, M.E.; Darling, W.G.

    1998-01-01

    Agricultural irrigation with wastewater is widely practised in Mexico, often in areas where the underlying aquifers are used for potable water supply. Studies in two areas of the country have examined the fate and behaviour of contaminants from untreated wastewater. The use of δ 18 O and δ 2 H isotopes was integrated with hydrogeological techniques such as core drilling, geophysics, major ion and trace element analysis of water samples, soil sampling and simple modelling. In both study areas, the isotope data helped to confirm the hydrochemical results. Conventional plots of δ 2 H and δ 18 O provide indications of altitude differences and evaporation processes in looking at sources of recharge. Plotting δ 18 O against chloride provides a convenient way of distinguishing groundwater types. In Leon, isotopic data confirmed that recharge to the deep volcanic-rock aquifer underlying the area of wastewater irrigation came partly from the surrounding mountains where this formation outcrops. In the Mezquital Valley, recharge to groundwaters beneath the valley floor originates from infiltration of wastewater. Comparison with data from 25 years ago indicated that isotopic compositions at some locations have become significantly less depleted in δ 18 O, suggesting that the contribution from irrigation water had increased. The study has demonstrated the importance of establishing good conceptual models at an early stage of such investigations, particularly where multiple and changing sources of groundwater recharge are anticipated. (author)

  5. A North Sea approach for Mexico?; El marco Mar del Norte para Mexico?

    Energy Technology Data Exchange (ETDEWEB)

    Baker, George [ENERGIA.com, United States (United States)

    2006-11-15

    The probable existence of oil and gas deposits in the border territory between Mexico and the United States has waked up an enormous restlessness given the lack of agreements and stipulations on the handling of such deposits; cases like this one have occurred in other parts of the globe and it is indeed the intention of this article to show how the agreement decided on the North Sea can be applied in the case of Mexico. The bilateral characteristics of this agreement conformed by incentives and openings to the market, require the cooperation of different offices and governmental sectors from the federal government to make a series of possible stipulations that regulate the treaty and allow different oil companies a substantial interaction that profits the owners on both sides of the border. In Mexico the responsibility to put in action projects of this type corresponds to the legislative power in complicity with the secretariats of Foreign Affairs and Work. The present action models and the monopoly of Petroleos Mexicanos (PEMEX) in Mexico have only managed to suspend the development of the country in this sector and to maintain the oil industry development in a mediocre and deteriorated level. The benefits of such an adjustment would extend beyond obtaining a bilateral development for the involved countries; nevertheless we remember that the government of the United States is not to the compass of the governments pro-unification of borders. In order to begin the unification of the border regions, Mexico must document the location of border wells, nevertheless even though any agreement could be reached, years would have to pass before PEMEX develops the appropriate technology to operate its part of the deposits. [Spanish] La probable existencia de yacimientos de petroleo y gas en el territorio fronterizo entre Mexico y Estados Unidos ha despertado una enorme inquietud dada la falta de acuerdos y estipulaciones sobre la manipulacion de tales yacimientos; casos como

  6. Primary production and algae diversity vs. pollution in xochimilco wet-lands

    Energy Technology Data Exchange (ETDEWEB)

    Pedroza-Pichardo, R.; Hernandez-Delgadillo, R.; Boll-Arguello, G.

    2009-07-01

    Xochimilco is an ancient endorheic lake located in the Valley of Mexico. Due to its shallow water and the freshwater springs that lined the canals, they are surround raised agricultural fields called chinampas. Since the Valley of Mexico was originally wetlands, the chinampas were the most productive means of agricultural production. Xochimilco are considered one of the most important urban lungs in Mexico City. However, it is not clear how the huge urbanization around is to know if there is a correlation between primary production (PP), algae diversity, BOD{sub 5} and faecal coliforms. Sample collection was done every month over a year at six different canals named: Embarcadero Celada, Embarcadero Nuevo Nativitas, Canal Las Abejas, Canal Zacapa, Canal Santo Domingo y Canal Nacional. (Author)

  7. Primary production and algae diversity vs. pollution in xochimilco wet-lands

    International Nuclear Information System (INIS)

    Pedroza-Pichardo, R.; Hernandez-Delgadillo, R.; Boll-Arguello, G.

    2009-01-01

    Xochimilco is an ancient endorheic lake located in the Valley of Mexico. Due to its shallow water and the freshwater springs that lined the canals, they are surround raised agricultural fields called chinampas. Since the Valley of Mexico was originally wetlands, the chinampas were the most productive means of agricultural production. Xochimilco are considered one of the most important urban lungs in Mexico City. However, it is not clear how the huge urbanization around is to know if there is a correlation between primary production (PP), algae diversity, BOD 5 and faecal coliforms. Sample collection was done every month over a year at six different canals named: Embarcadero Celada, Embarcadero Nuevo Nativitas, Canal Las Abejas, Canal Zacapa, Canal Santo Domingo y Canal Nacional. (Author)

  8. A preliminary research of characteristic of selected frequency luminescence for debris flow in Jiangjiagou valley

    International Nuclear Information System (INIS)

    Liu Zhaowen; Wei Mingjian; Li Dongxu; Pan Baolin; Ge Yonggang

    2009-01-01

    Four debris flow samples were separated from Nidepin, Duozhao and Dawazigou valleys in Jiangjiagou valley area, Yunnan province. They were measured with BG2003 luminescence spectrograph. The characteristic spectra of the selected frequency luminescence of samples from the different locations were obtained. The wave length of emission photons from samples of Dawazigou valley and Jiangjia valley are 300, 310, 320, 400 and 460 nm when it was using blue light (488)nm excited. When the green light (532 nm) has been used to excited, the wave length of emission photons from samples of Dawazigou valley and Duozhao valley are similar high at 310 and 320 nm. Furthermore, using the green light excited the samples from desert sand at the same lab condition; the number of absorbed photons of samples from desert sand is much higher than from debris flow. (authors)

  9. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Quality Control Region. 81.48 Section 81.48 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of the...

  10. Silicon Valley: Planet Startup : Disruptive Innovation, Passionate Entrepreneurship & High-tech Startups

    NARCIS (Netherlands)

    dr. A. Maas; Dr. P. Ester

    2016-01-01

    For decades now, Silicon Valley has been the home of the future. It's the birthplace of the world's most successful high-tech companies-including Apple, Yahoo, Google, Facebook, Twitter, and many more. So what's the secret? What is it about Silicon Valley that fosters entrepreneurship and

  11. 78 FR 59840 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Science.gov (United States)

    2013-09-30

    ...] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District... of plan. * * * * * (c) * * * (428) * * * (i) * * * (B) Antelope Valley Air Quality Management...) * * * (i) * * * (B) Antelope Valley Air Quality Management District. (1) Rule 431.1, ``Sulfur Content of...

  12. 78 FR 45114 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Science.gov (United States)

    2013-07-26

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... the Antelope Valley Air Quality Management District (AVAQMD) portion of the California State... for the South Coast Air Quality Management District (SCAQMD). The Antelope Valley Air Pollution...

  13. The daylight saving time in Mexico; El cambio de horario durante la epoca del verano en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Covarrubias Ramos, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The daylight saving time in Mexico for energy saving is analyzed; such a change is made forwarding the clocks one hour in all Mexico the first Sunday of April and backing them an hour the last Sunday of October. Mention is made the reasons why Mexico adopted this measure, the social-economic impact that brings along and the benefits of this daylight saving time. The case of countries that also apply this measure is analyzed. It is expected that this measure attains benefits for the society either collectively or individually through the ecology and the economy. [Espanol] Se analiza el cambio de horario en la epoca de verano en Mexico para ahorrar energia; dicho cambio se realiza al adelantar una hora al reloj en todo el territorio de Mexico el primer domingo de abril y retrazarlo una hora el ultimo domingo de octubre. Se mencionan las razones por las cuales Mexico adopto esta medida, el impacto socio-economico que traera consigo y los beneficios del cambio de horario. Se aborda la situacion de los paises que tambien aplican esta medida. Se espera que esta medida logre beneficios para la sociedad, ya sea en modo colectivo o individual, para la ecologia y para la economia.

  14. The daylight saving time in Mexico; El cambio de horario durante la epoca del verano en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Covarrubias Ramos, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The daylight saving time in Mexico for energy saving is analyzed; such a change is made forwarding the clocks one hour in all Mexico the first Sunday of April and backing them an hour the last Sunday of October. Mention is made the reasons why Mexico adopted this measure, the social-economic impact that brings along and the benefits of this daylight saving time. The case of countries that also apply this measure is analyzed. It is expected that this measure attains benefits for the society either collectively or individually through the ecology and the economy. [Espanol] Se analiza el cambio de horario en la epoca de verano en Mexico para ahorrar energia; dicho cambio se realiza al adelantar una hora al reloj en todo el territorio de Mexico el primer domingo de abril y retrazarlo una hora el ultimo domingo de octubre. Se mencionan las razones por las cuales Mexico adopto esta medida, el impacto socio-economico que traera consigo y los beneficios del cambio de horario. Se aborda la situacion de los paises que tambien aplican esta medida. Se espera que esta medida logre beneficios para la sociedad, ya sea en modo colectivo o individual, para la ecologia y para la economia.

  15. Working without a Union in New Mexico

    Science.gov (United States)

    Adele, Niame; Rack, Christine

    2008-01-01

    In this article, the authors provide a description of the academic climate in New Mexico. Like many other places in the world today, New Mexico is trying to find an identity in an environment that the authors label "increasingly privatized, corporatized, and militarized." New Mexico's higher education salaries are lower than those in…

  16. Long Valley Caldera-Mammoth Mountain unrest: The knowns and unknowns

    Science.gov (United States)

    Hill, David P.

    2017-01-01

    This perspective is based largely on my study of the Long Valley Caldera (California, USA) over the past 40 years. Here, I’ll examine the “knowns” and the “known unknowns” of the complex tectonic–magmatic system of the Long Valley Caldera volcanic complex. I will also offer a few brief thoughts on the “unknown unknowns” of this system.

  17. Geological and seismic evaluation of a Lower Mannville valley system; Alderson Prospect, Rolling Hills, southeastern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, J.C.; Lawton, D.C.; Gunn, J.D.

    1987-09-01

    A Lower Mannville valley complex cutting into Jurassic and Mississippian strata in southeastern Alberta was identified on a conventional seismic section. The valley was drilled and a twenty metre core of muddy sandstone was recovered from the target interval. Oil staining was visible within the core but tests showed only muddy water. In contrast, thin sands adjacent to the channel tested up to 300 m/sup 3//day gas and 800 m oil. Sediments adjacent to the valley are interpreted as contemporaneous levee splay deposits of a channel that occupied the valley, whereas the muddy sandstones within the channel represent either a fine grained point bar, or an abandoned channel-fill deposit. In the latter case, coarse grained, sandy, point bar deposits can be expected to occur elsewhere in the channel system. Oil is trapped in crevasse splay deposits draped over a local Mississippian high, but not in the valley because of poor reservoir quality of the channel sandstone. The internal geometry of the valley fill cannot be resolved directly from the seismic data because of the small size of the channel. However, the geometry of reflections from sediments directly above the valley shows variation in the fill and implies that, at the test location, the valley fill is an abandoned channel deposit. It is proposed here that reflection geometry above Lower Mannville valleys can provide a means of determining the type of valley fill. 11 figs., 1 tab., 29 illus.

  18. Interaction Induced Quantum Valley Hall Effect in Graphene

    Directory of Open Access Journals (Sweden)

    E. C. Marino

    2015-03-01

    Full Text Available We use pseudo-quantum electrodynamics in order to describe the full electromagnetic interaction of the p electrons in graphene in a consistent 2D formulation. We first consider the effect of this interaction in the vacuum polarization tensor or, equivalently, in the current correlator. This allows us to obtain the T→0 conductivity after a smooth zero-frequency limit is taken in Kubo’s formula. Thereby, we obtain the usual expression for the minimal conductivity plus corrections due to the interaction that bring it closer to the experimental value. We then predict the onset of an interaction-driven spontaneous quantum valley Hall effect below an activation temperature of the order of 2 K. The transverse (Hall valley conductivity is evaluated exactly and shown to coincide with the one in the usual quantum Hall effect. Finally, by considering the effects of pseudo-quantum electrodynamics, we show that the electron self-energy is such that a set of P- and T-symmetric gapped electron energy eigenstates are dynamically generated, in association with the quantum valley Hall effect.

  19. Topological induced valley polarization in bilayer graphene/Boron Nitride

    Science.gov (United States)

    Basile, Leonardo; Idrobo, Juan C.

    2015-03-01

    Novel electronic devices relay in our ability to control internal quantum degrees of freedom of the electron e.g., its spin. The valley number degree of freedom is a pseudospin that labels degenerate eigenstates at local maximum/minimum on the valence/conduction band. Valley polarization, that is, selective electronic localization in a momentum valley and its manipulation can be achieved by means of circular polarized light (CPL) in a system with strong spin-orbit coupling (SOC). In this talk, we will show theoretically that despite the fact that neither graphene or BN have a strong SOC, a bilayer of graphene on BN oriented at a twist angle has different absorption for right- and left- CPL. This induced polarization occurs due to band folding of the electronic bands, i.e., it has a topological origin. This research was supported EPN multidisciplinary grant and by DOE SUFD MSED.

  20. Resonant tunneling spectroscopy of valley eigenstates on a donor-quantum dot coupled system

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, T., E-mail: t.kobayashi@unsw.edu.au; Heijden, J. van der; House, M. G.; Hile, S. J.; Asshoff, P.; Simmons, M. Y.; Rogge, S. [Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney 2052 New South Wales (Australia); Gonzalez-Zalba, M. F. [Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Vinet, M. [Université Grenoble-Alpes and CEA, LETI, MINATEC, 38000 Grenoble (France)

    2016-04-11

    We report on electronic transport measurements through a silicon double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO{sub 2} interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160 and 240 μeV with an electric field dependence 1.2 ± 0.2 meV/(MV/m). A large valley splitting is an essential requirement for implementing a physical electron spin qubit in a silicon quantum dot.

  1. 76 FR 38572 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Science.gov (United States)

    2011-07-01

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... approve revisions to the Antelope Valley Air Quality Management District (AVAQMD) portion of the... approving with the dates that they were adopted by the Antelope Valley Air Quality Management District...

  2. Energy, environment and development in Mexico

    International Nuclear Information System (INIS)

    Lohmann, J.

    1990-01-01

    Mexico is a country at the crossroads. It has huge potentials in energy, in natural resources and in human resources. It is currently experiencing one of the most serious crises in its history - economic, ecological, political - and it is making efforts to overcome the problems behind these crises, which may affect us all because of Mexico's importance as energy producer and energy consumer. Mexico is one of the developing countries which has participated actively in finding solutions to the worlds environmental problems not least the problem of climatic changes as a result of increasing energy consumption. Mexico is seeing the consequences at local and national level, and is taking steps to change course. At the same time, it has also expressed interest in participating in international initiatives and cooperation to solve these problem. But Mexico finds itself in a situation not unlike that of many East European countries after the fall of the communist regimes. The old system is tumbling, the will to change is present, but there is a lack of resources. 123 refs., 45 tabs

  3. Mapping Ecosystem Services in the Jordan Valley, Jordan

    Science.gov (United States)

    Luz, Ana; Marques, Ana; Ribeiro, Inês; Alho, Maria; Catarina Afonso, Ana; Almeida, Erika; Branquinho, Cristina; Talozi, Samer; Pinho, Pedro

    2016-04-01

    In the last decade researchers started using ecosystem services as a new framework to understand the relationships between environment and society. Habitat quality and water quality are related with ecosystem services regulation and maintenance, or even provision. According to the Common International Classification of Ecosystem Services (CICES) both habitat quality and water quality are associated with lifecycle maintenance, habitat and gene pool protection, and water conditions, among others. As there is increased pressure on habitats and rivers especially for agricultural development, mapping and evaluating habitat and water quality has important implications for resource management and conservation, as well as for rural development. Here, we model and map habitat and water quality in the Jordan Valley, Jordan. In this study, we aim to identify and analyse ecosystem services both through 1) habitat quality and 2) water quality modelling using InVest, an integrated valuation of ecosystem services and tradeoffs. The data used in this study mainly includes the LULC, Jordan River watershed and main threats and pollutants in the study area, such as agriculture, industry, fish farms and urbanization. Results suggest a higher pressure on natural habitats in the Northern region of the Jordan Valley, where industry is dominant. Agriculture is present along the Jordan Valley and limits the few natural forested areas. Further, water pollution is mainly concentrated in disposal sites due to the low flow of the Jordan River. Our results can help to identify areas where natural resources and water resource management is most needed in the Jordan Valley. Acknowledgements: Transbasin FP7 project

  4. Controls on valley spacing in landscapes subject to rapid base-level fall

    Science.gov (United States)

    McGuire, Luke; Pelletier, John D.

    2015-01-01

    What controls the architecture of drainage networks is a fundamental question in geomorphology. Recent work has elucidated the mechanisms of drainage network development in steadily uplifting landscapes, but the controls on drainage-network morphology in transient landscapes are relatively unknown. In this paper we exploit natural experiments in drainage network development in incised Plio-Quaternary alluvial fan surfaces in order to understand and quantify drainage network development in highly transient landscapes, i.e. initially unincised low-relief surfaces that experience a pulse of rapid base-level drop followed by relative base-level stasis. Parallel drainage networks formed on incised alluvial-fan surfaces tend to have a drainage spacing that is approximately proportional to the magnitude of the base-level drop. Numerical experiments suggest that this observed relationship between the magnitude of base-level drop and mean drainage spacing is the result of feedbacks among the depth of valley incision, mass wasting and nonlinear increases in the rate of colluvial sediment transport with slope gradient on steep valley side slopes that lead to increasingly wide valleys in cases of larger base-level drop. We identify a threshold magnitude of base-level drop above which side slopes lengthen sufficiently to promote increases in contributing area and fluvial incision rates that lead to branching and encourage drainage networks to transition from systems of first-order valleys to systems of higher-order, branching valleys. The headward growth of these branching tributaries prevents the development of adjacent, ephemeral drainages and promotes a higher mean valley spacing relative to cases in which tributaries do not form. Model results offer additional insights into the response of initially unincised landscapes to rapid base-level drop and provide a preliminary basis for understanding how varying amounts of base-level change influence valley network morphology.

  5. Generation and electric control of spin-valley-coupled circular photogalvanic current in WSe2

    Science.gov (United States)

    Yuan, Hongtao; Hwang, Harold Y.; Cui, Yi

    2015-03-01

    Compared to the weak spin-orbit-interaction (SOI) in graphene, layered transitionmetal chalcogenides MX2 have heavy 4d/5d elements with strong atomic SOI, providing a unique way to extend functionalities of novel spintronics and valleytronics devices. Such a valley polarization achieved via valley-selective circular dichroism has been predicted theoretically and demonstrated with optical experiments in MX2 systems. Despite the exciting progresses, the generation of a valley/spin current by valley polarization in MX2 remains elusive and a great challenge. A spin/valley current in MX2 compounds caused by such a valley polarization has never been observed, nor its electric-field control. In this talk, we demonstrated, within an electric-double-layer transistor based on WSe2, the manipulation of a spin-coupled valley photocurrent whose direction and magnitude depend on the degree of circular polarization of the incident radiation and can be further greatly modulated with an external electric field. Such room temperature generation and electric control of valley/spin photocurrent provides a new property of electrons in MX2 systems, thereby enabling new degrees of control for quantum-confined spintronics devices. (In collaboration with S.C. Zhang, Y.L. Chen, Z.X. Shen, B Lian, H.J. Zhang, G Xu, Y Xu, B Zhou, X.Q. Wang, B Shen X.F. Fang) Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515. Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515.

  6. Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators

    Science.gov (United States)

    Slobozhanyuk, Alexey

    2018-01-01

    Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage (1–3). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light (4–6). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom. PMID:29756032

  7. Valley dynamics of intravalley and intervalley multiexcitonic states in monolayer WS2

    Science.gov (United States)

    Fu, Jiyong; Bezerra, Andre; Qu, Fanyao

    2018-03-01

    We present a comprehensive model comprising of a complete set of rate equations, which account for charge transfer among multiexcitonic channels including excitons, trions, and biexcitons, to investigate valley (locked with spin) dynamics in monolayer WS2. The steady-state photoluminescence (PL) spectra, underlying the laser power dependence of excitonic populations, are also determined. Our computed PL for all excitonic states agrees with the experimental data of Paradisanos et al. [Appl. Phys. Lett. 110, 193102 (2017), 10.1063/1.4983285]. We find that the relative weight of PL, stemmed from different excitonic channels, strongly depends on the laser power even under dynamical conditions. Remarkably, the biexciton channel, having the weakest PL intensity at low laser powers, tends to prevail in PL over other excitonic states as the power strengthens. In addition, by accounting for intervalley scatterings, which enable transfer of excitonic states from one valley to the other, we determine the valley polarization, which strongly depends on intervalley scatterings and the exciton generation rates in the two valleys. On the other hand, the valley polarization for all excitonic channels is found almost independent of the laser power, consistent with experimental measurements as well. Finally, the valley dynamics involving both intra- and intervalley trions is discussed. Our model and numerical outcome should be beneficial to experiments especially featuring the interplay of multiexcitonic channels in, e.g., elucidating experimental data, estimating central excitonic quantities including recombination times and transition rates, and in widening possible new experimental scopes.

  8. Occupational health in Mexico.

    Science.gov (United States)

    Carreón, Tania; Santos-Burgoa, Carlos; Baron, Sherry; Hernández, Sendy

    2002-01-01

    The authors discuss the maquiladoras and child labor, and offer an overview of the history of occupational safety and health in Mexico that covers laws and regulations, social security, unions, and enforcement of legislation. The organization and structure of the various institutions responsible for occupational safety and health (OSH), as well as administrative procedures, are described. This article concludes with a list of the new challenges for OSH in Mexico.

  9. The browse value of the Eastern Cape valley bushveld. | A.J. ...

    African Journals Online (AJOL)

    The feeding value of the Eastern Cape Valley Bushveld in terms of crude protein, digestible dry matter, digestible energy and metabolic energy, as selected by oesophageal fistulated Boer- and Angora goats was determined. Results show that the Valley Bushveld maintains a high feed value throughout the year. The high ...

  10. 78 FR 57629 - Eagle Valley Clean Energy, LLC; Notice of Filing

    Science.gov (United States)

    2013-09-19

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. EL13-87-000; QF13-658-000] Eagle Valley Clean Energy, LLC; Notice of Filing Take notice that on September 9, 2013, Eagle Valley Clean Energy, LLC filed Form 556 and a petition for certification as a qualifying small power production...

  11. Electric power and environment in Mexico

    International Nuclear Information System (INIS)

    Quintanilla, J.

    1997-01-01

    This volume is one of the three resulting volumes about the project named Document analysis and prospective organized by the National Autonomous University of Mexico (UNAM) through it University Energy Program (PUE). It is a non-periodical publication collection of the variable content and extent that as a whole constitutes an information heritage and an original contribution about the energy problematic as International level as at the country context and the University activities. In this book the manners of producing electrical energy are discussed, so how satisfying the growing necessities of this energy in Mexico without contaminating environment and how doing rational and efficient use of energy. The content of each document of this book is however exclusive responsibility of authors, as in the information as in their told opinions. The following papers were presented: 1) Hydroelectricity, soils use and water management. 2) The electric generation in Mexico and its environmental impacts: Past, present and future. 3) The nucleo electricity and the radioactive materials management. 4) Exposure to electromagnetic fields and its association with leukemia in children. 5) The electric power in Mexico and the supportable development. 6) Potential of electric generation at great scale with eolic energy in Mexico. 7) Toward an electric generation scheme distributed with non-conventional energies. 8) Renewable sources of energy in Mexico at the Century 21. (Author)

  12. Mesozoic Continental Sediment-dispersal Systems of Mexico Linked to Development of the Gulf of Mexico

    Science.gov (United States)

    Lawton, T. F.; Molina-Garza, R. S.; Barboza-Gudiño, R.; Rogers, R. D.

    2013-05-01

    Major sediment dispersal systems on western Pangea evolved in concert with thermal uplift, rift and drift phases of the Gulf of Mexico Basin, and were influenced by development of a continental arc on Pangea's western margin. Existing literature and preliminary data from fieldwork, sandstone petrology and detrital zircon analysis reveal how major drainages in Mexico changed from Late Triassic through Late Jurassic time and offer predictions for the ultimate destinations of sand-rich detritus along the Gulf and paleo-Pacific margins. Late Triassic rivers drained away from and across the present site of the Gulf of Mexico, which was then the location of a major thermal dome, the Texas uplift of recent literature. These high-discharge rivers with relatively mature sediment composition fed a large-volume submarine fan system on the paleo-Pacific continental margin of Mexico. Predictably, detrital zircon age populations are diverse and record sources as far away as the Amazonian craton. This enormous fluvial system was cut off abruptly near the Triassic-Jurassic boundary by extensive reorganization of continental drainages. Early and Middle Jurassic drainage systems had local headwaters and deposited sediment in extensional basins associated with arc magmatism. Redbeds accumulated across northern and eastern Mexico and Chiapas in long, narrow basins whose locations and dimensions are recorded primarily by inverted antiformal massifs. The Jurassic continental successions overlie Upper Triassic strata and local subvolcanic plutons; they contain interbedded volcanic rocks and thus have been interpreted as part of the Nazas continental-margin arc. The detritus of these fluvial systems is volcanic-lithic; syndepositional grain ages are common in the detrital zircon populations, which are mixed with Oaxaquia-derived Permo-Triassic and Grenville age populations. By this time, interior Pangea no longer supplied sediment to the paleo-Pacific margin, possibly because the

  13. Many-body effects in valleytronics: direct measurement of valley lifetimes in single-layer MoS2.

    Science.gov (United States)

    Mai, Cong; Barrette, Andrew; Yu, Yifei; Semenov, Yuriy G; Kim, Ki Wook; Cao, Linyou; Gundogdu, Kenan

    2014-01-08

    Single layer MoS2 is an ideal material for the emerging field of "valleytronics" in which charge carrier momentum can be finely controlled by optical excitation. This system is also known to exhibit strong many-body interactions as observed by tightly bound excitons and trions. Here we report direct measurements of valley relaxation dynamics in single layer MoS2, by using ultrafast transient absorption spectroscopy. Our results show that strong Coulomb interactions significantly impact valley population dynamics. Initial excitation by circularly polarized light creates electron-hole pairs within the K-valley. These excitons coherently couple to dark intervalley excitonic states, which facilitate fast electron valley depolarization. Hole valley relaxation is delayed up to about 10 ps due to nondegeneracy of the valence band spin states. Intervalley biexciton formation reveals the hole valley relaxation dynamics. We observe that biexcitons form with more than an order of magnitude larger binding energy compared to conventional semiconductors. These measurements provide significant insight into valley specific processes in 2D semiconductors. Hence they could be used to suggest routes to design semiconducting materials that enable control of valley polarization.

  14. Large valley splitting in monolayer WS2 by proximity coupling to an insulating antiferromagnetic substrate

    Science.gov (United States)

    Xu, Lei; Yang, Ming; Shen, Lei; Zhou, Jun; Zhu, Tao; Feng, Yuan Ping

    2018-01-01

    Lifting the valley degeneracy is an efficient way to achieve valley polarization for further valleytronics operations. In this Rapid Communication, we demonstrate that a large valley splitting can be obtained in monolayer transition metal dichalcogenides by magnetic proximity coupling to an insulating antiferromagnetic substrate. As an example, we perform first-principles calculations to investigate the electronic structures of monolayer WS2 on the MnO(111) surface. Our calculation results suggest that a large valley splitting of 214 meV, which corresponds to a Zeeman magnetic field of 1516 T, is induced in the valence band of monolayer WS2. The magnitude of valley splitting relies on the strength of interfacial orbital hybridization and can be tuned continually by applying an external out-of-plane pressure and in-plane strain. More interestingly, we find that both spin and valley index will flip when the magnetic ordering of MnO is reversed. Besides, owing to the sizable Berry curvature and time-reversal symmetry breaking in the WS2/MnO heterostructure, a spin- and valley-polarized anomalous Hall current can be generated in the presence of an in-plane electric field, which allows one to detect valleys by the electrical approach. Our results shed light on the realization of valleytronic devices using the antiferromagnetic insulator as the substrate.

  15. Hydrology of modern and late Holocene lakes, Death Valley, California

    International Nuclear Information System (INIS)

    Grasso, D.N.

    1996-01-01

    Above-normal precipitation and surface-water runoff, which have been generally related to the cyclic recurrence of the El Nino-Southern Oscillation, have produced modern ephemeral lakes in the closed-basin Death Valley watershed. This study evaluates the regional hydroclimatic relations between precipitation, runoff, and lake transgressions in the Death Valley watershed. Recorded precipitation, runoff, and spring discharge data for the region are used in conjunction with a closed-basin, lake-water-budget equation to assess the relative contributions of water from these sources to modern lakes in Death Valley and to identify the requisite hydroclimatic changes for a late Holocene perennial lake in the valley. As part of the Yucca Mountain Site Characterization Program, an evaluation of the Quaternary regional paleoflood hydrology of the potential nuclear-waste repository site at Yucca Mountain, Nevada, was planned. The objectives of the evaluation were (1) to identify the locations and investigate the hydraulic characteristics of paleofloods and compare these with the locations and characteristics of modern floods, and (2) to evaluate the character and severity of past floods and debris flows to ascertain the potential future hazards to the potential repository during the pre-closure period (US Department of Energy, 1988). This study addresses the first of these objectives, and the second in part, by assessing and comparing the sizes, locations, and recurrence rates of modern, recorded (1962--83) floods and late Holocene paleofloods for the 8,533-mi 2 , closed-basin, Death Valley watershed with its contributing drainage basins in the Yucca Mountain site area

  16. Hydrology of modern and late Holocene lakes, Death Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, D.N.

    1996-07-01

    Above-normal precipitation and surface-water runoff, which have been generally related to the cyclic recurrence of the El Nino-Southern Oscillation, have produced modern ephemeral lakes in the closed-basin Death Valley watershed. This study evaluates the regional hydroclimatic relations between precipitation, runoff, and lake transgressions in the Death Valley watershed. Recorded precipitation, runoff, and spring discharge data for the region are used in conjunction with a closed-basin, lake-water-budget equation to assess the relative contributions of water from these sources to modern lakes in Death Valley and to identify the requisite hydroclimatic changes for a late Holocene perennial lake in the valley. As part of the Yucca Mountain Site Characterization Program, an evaluation of the Quaternary regional paleoflood hydrology of the potential nuclear-waste repository site at Yucca Mountain, Nevada, was planned. The objectives of the evaluation were (1) to identify the locations and investigate the hydraulic characteristics of paleofloods and compare these with the locations and characteristics of modern floods, and (2) to evaluate the character and severity of past floods and debris flows to ascertain the potential future hazards to the potential repository during the pre-closure period (US Department of Energy, 1988). This study addresses the first of these objectives, and the second in part, by assessing and comparing the sizes, locations, and recurrence rates of modern, recorded (1962--83) floods and late Holocene paleofloods for the 8,533-mi{sup 2}, closed-basin, Death Valley watershed with its contributing drainage basins in the Yucca Mountain site area.

  17. Technical Analysis of In-Valley Drainage Management Strategies for the Western San Joaquin Valley, California

    Science.gov (United States)

    Presser, Theresa S.; Schwarzbach, Steven E.

    2008-01-01

    The western San Joaquin Valley is one of the most productive farming areas in the United States, but salt-buildup in soils and shallow groundwater aquifers threatens this area?s productivity. Elevated selenium concentrations in soils and groundwater complicate drainage management and salt disposal. In this document, we evaluate constraints on drainage management and implications of various approaches to management considered in: *the San Luis Drainage Feature Re-Evaluation (SLDFRE) Environmental Impact Statement (EIS) (about 5,000 pages of documentation, including supporting technical reports and appendices); *recent conceptual plans put forward by the San Luis Unit (SLU) contractors (i.e., the SLU Plans) (about 6 pages of documentation); *approaches recommended by the San Joaquin Valley Drainage Program (SJVDP) (1990a); and *other U.S. Geological Survey (USGS) models and analysis relevant to the western San Joaquin Valley. The alternatives developed in the SLDFRE EIS and other recently proposed drainage plans (refer to appendix A for details) differ from the strategies proposed by the San Joaquin Valley Drainage Program (1990a). The Bureau of Reclamation (USBR) in March 2007 signed a record of decision for an in-valley disposal option that would retire 194,000 acres of land, build 1,900 acres of evaporation ponds, and develop a treatment system to remove salt and selenium from drainwater. The recently proposed SLU Plans emphasize pumping drainage to the surface, storing approximately 33% in agricultural water re-use areas, treating selenium through biotechnology, enhancing the evaporation of water to concentrate salt, and identifying ultimate storage facilities for the remaining approximately 67% of waste selenium and salt. The treatment sequence of reuse, reverse osmosis, selenium bio-treatment, and enhanced solar evaporation is unprecedented and untested at the scale needed to meet plan requirements. All drainage management strategies that have been proposed

  18. Upper Neogene stratigraphy and tectonics of Death Valley — a review

    Science.gov (United States)

    Knott, J. R.; Sarna-Wojcicki, A. M.; Machette, M. N.; Klinger, R. E.

    2005-12-01

    New tephrochronologic, soil-stratigraphic and radiometric-dating studies over the last 10 years have generated a robust numerical stratigraphy for Upper Neogene sedimentary deposits throughout Death Valley. Critical to this improved stratigraphy are correlated or radiometrically-dated tephra beds and tuffs that range in age from > 3.58 Ma to Mormon Point. This new geochronology also establishes maximum and minimum ages for Quaternary alluvial fans and Lake Manly deposits. Facies associated with the tephra beds show that ˜3.3 Ma the Furnace Creek basin was a northwest-southeast-trending lake flanked by alluvial fans. This paleolake extended from the Furnace Creek to Ubehebe. Based on the new stratigraphy, the Death Valley fault system can be divided into four main fault zones: the dextral, Quaternary-age Northern Death Valley fault zone; the dextral, pre-Quaternary Furnace Creek fault zone; the oblique-normal Black Mountains fault zone; and the dextral Southern Death Valley fault zone. Post - 3.3 Ma geometric, structural, and kinematic changes in the Black Mountains and Towne Pass fault zones led to the break up of Furnace Creek basin and uplift of the Copper Canyon and Nova basins. Internal kinematics of northern Death Valley are interpreted as either rotation of blocks or normal slip along the northeast-southwest-trending Towne Pass and Tin Mountain fault zones within the Eastern California shear zone.

  19. Visual Resource Analysis for Solar Energy Zones in the San Luis Valley

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Robert [Argonne National Laboratory (ANL), Argonne, IL (United States). Environmental Science Division; Abplanalp, Jennifer M. [Argonne National Laboratory (ANL), Argonne, IL (United States). Environmental Science Division; Zvolanek, Emily [Argonne National Laboratory (ANL), Argonne, IL (United States). Environmental Science Division; Brown, Jeffery [Bureau of Land Management, Washington, DC (United States). Dept. of the Interior

    2016-01-01

    This report summarizes the results of a study conducted by Argonne National Laboratory’s (Argonne’s) Environmental Science Division for the U.S. Department of the Interior Bureau of Land Management (BLM). The study analyzed the regional effects of potential visual impacts of solar energy development on three BLM-designated solar energy zones (SEZs) in the San Luis Valley (SLV) in Colorado, and, based on the analysis, made recommendations for or against regional compensatory mitigation to compensate residents and other stakeholders for the potential visual impacts to the SEZs. The analysis was conducted as part of the solar regional mitigation strategy (SRMS) task conducted by BLM Colorado with assistance from Argonne. Two separate analyses were performed. The first analysis, referred to as the VSA Analysis, analyzed the potential visual impacts of solar energy development in the SEZs on nearby visually sensitive areas (VSAs), and, based on the impact analyses, made recommendations for or against regional compensatory mitigation. VSAs are locations for which some type of visual sensitivity has been identified, either because the location is an area of high scenic value or because it is a location from which people view the surrounding landscape and attach some level of importance or sensitivity to what is seen from the location. The VSA analysis included both BLM-administered lands in Colorado and in the Taos FO in New Mexico. The second analysis, referred to as the SEZ Analysis, used BLM visual resource inventory (VRI) and other data on visual resources in the former Saguache and La Jara Field Offices (FOs), now contained within the San Luis Valley FO (SLFO), to determine whether the changes in scenic values that would result from the development of utility-scale solar energy facilities in the SEZs would affect the quality and quantity of valued scenic resources in the SLV region as a whole. If the regional effects were judged to be significant, regional

  20. New Mexico Museums and Cultural Centers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the locations of museums and cultural centers in New Mexico, in point form, with limited attributes, compiled using...

  1. The World of Great Wines: The Douro Valley Experience

    OpenAIRE

    A. Oliveira-Brochado; R. Silva; C. Paulino

    2014-01-01

    The aim of this paper is to use an experiential view of wine tourism to develop a battery of items that can potentially capture the overall Douro Valley experience from the tourist’s perspective. The Douro Valley, a UNESCO World Heritage region located in Portugal, was the target of this study. The research took a mixed approach using both qualitative and quantitative designs. Firstly, we combine the literature review on service quality scales with a content analysis of five in-depth intervie...

  2. Digital Geologic Map of New Mexico - Volcanic Vents

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The geologic map was created in GSMAP at Socorro, New Mexico by Orin Anderson and Glen Jones and published as the Geologic Map of New Mexico 1:500,000 in GSMAP...

  3. Road infrastructure and mobility of consumption in the Mexicali-Imperial Valley border area

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray-Moctezuma

    2015-06-01

    Full Text Available The objective of this study is to analyze the mobility of consumption in the Mexicali-Imperial Valley border area. The study shows that the population in the Mexicali sections closer to border crossings generates the greatest amount of consumption dynamics with places located in Imperial Valley. Conversely, Imperial Valley sections that are more distant from the border concentrate a greater number of destination sites for these cross-border trips. It is concluded that a higher quality and more integrated road infrastructure allows the new consumption centers in Imperial Valley to be located farther away from the border and that the Mexicali population with visas can cross indiscriminately through any border crossing by taking longer journeys toward these centers.

  4. Irrigation channels of the Upper Rhone valley (Switzerland). Geomorphological analysis of a cultural heritage

    Science.gov (United States)

    Reynard, Emmanuel

    2016-04-01

    The Upper Rhone valley (Canton of Valais, Switzerland) is characterised by dry climatic conditions that explain the presence of an important network (about 800 km) of irrigation channels - called Bisses in the French-speaking part of the canton or Suonen in the German-speaking area - dating back to the Middle Ages. This network constitutes a cultural heritage and during the last 30 years these agricultural infrastructures have sparked a renewed interest for tourist and cultural reasons. Indeed, the paths along the channels are used as tourist trails and several abandoned channels have been renovated for tourist use. Based on an inventory of the Bisses/Suonen of Valais, the proposed communication has three aims: (1) to analyse the geomorphological context (morphometric analysis, structural geomorphology, main processes) of various types of channels and to show the impact of the geomorphological context on the building techniques; (2) to identify particularly active processes along the channels; (3) to classify the Bisses/Suonen according to their geomorphological value and to their geomorphological sensitivity, and to propose managing measures. Structural and climatic conditions influence the geomorphological context of the channels. In a structural point of view, irrigation channels are developed in three main contexts: (1) in the Aar Massif crystalline basement; (2) in the limestone and marl cover nappes of the Helvetic Alps; (3) in the metamorphic cover nappes of the Penninic domain. The Rhone River valley is boarded by two high mountain ranges: the Penninic Alps in the South and the Bernese Alps in the North. Because of rain shadow effects, the climate is relatively dry and, between Brig and Martigny, annual rainfall is not more than 600 mm at 500 m ASL and 800 mm at 1600 m ASL. Nevertheless, due to important vertical precipitation gradients annual rainfall totals are high at high altitudes. On the southern facing tributary valleys, the dry climatic conditions

  5. Photoinduced quantum spin and valley Hall effects, and orbital magnetization in monolayer MoS2

    KAUST Repository

    Tahir, M.

    2014-09-22

    We theoretically demonstrate that 100% valley-polarized transport in monolayers of MoS2 and other group-VI dichalcogenides can be obtained using off-resonant circularly polarized light. By tuning the intensity of the off-resonant light the intrinsic band gap in one valley is reduced, while it is enhanced in the other valley, enabling single valley quantum transport. As a consequence, we predict (i) enhancement of the longitudinal electrical conductivity, accompanied by an increase in the spin polarization of the flowing electrons, (ii) enhancement of the intrinsic spin Hall effect, together with a reduction of the intrinsic valley Hall effect, and (iii) enhancement of the orbital magnetic moment and orbital magnetization. These mechanisms provide appealing opportunities to the design of nanoelectronics based on dichalcogenides.

  6. Photoinduced quantum spin and valley Hall effects, and orbital magnetization in monolayer MoS2

    KAUST Repository

    Tahir, M.; Manchon, Aurelien; Schwingenschlö gl, Udo

    2014-01-01

    We theoretically demonstrate that 100% valley-polarized transport in monolayers of MoS2 and other group-VI dichalcogenides can be obtained using off-resonant circularly polarized light. By tuning the intensity of the off-resonant light the intrinsic band gap in one valley is reduced, while it is enhanced in the other valley, enabling single valley quantum transport. As a consequence, we predict (i) enhancement of the longitudinal electrical conductivity, accompanied by an increase in the spin polarization of the flowing electrons, (ii) enhancement of the intrinsic spin Hall effect, together with a reduction of the intrinsic valley Hall effect, and (iii) enhancement of the orbital magnetic moment and orbital magnetization. These mechanisms provide appealing opportunities to the design of nanoelectronics based on dichalcogenides.

  7. Solar Energy within the Central Valley, CA: Current Practices and Potential

    Science.gov (United States)

    Hoffacker, M. K.; Hernandez, R. R.; Allen, M. F.

    2015-12-01

    Utility-scale solar energy (USSE, ≥ 1 megawatt [MW]) systems are rapidly being deployed in the Central Valley of California, generating clean electricity and new job opportunities. Utility-scale solar energy systems require substantial quantities of land or space, often prompting an evaluation of environmental impacts and trade-offs when selecting their placement. Utilizing salt-contaminated agricultural land (as the sodium absorption and electrical conductivity values are unsuitably high), unsuitable for food production, and lands within the built environment (developed), can serve as a co-benefit opportunity when reclamation of these lands for USSE development is prioritized. In this study, we quantify the theoretical and generation-based solar energy potential for the Central Valley according to land-cover type, crop type, and for salt-contaminated lands. Further, we utilize the Carnegie Energy and Environmental Compatibility (CEEC) model to identify and prioritize solar energy, integrating environmental resource opportunities and constraints most relevant to the Central Valley. We use the CEEC model to generate a value-based environmental compatibility output for the Central Valley. The Central Valley extends across nearly 60,000 km2 of California with the potential of generating 21,800 - 30,300 TWh y-1 and 41,600 TWh y-1 of solar energy for photovoltaic (PV) and concentrating solar power (CSP), respectively. Pasture, hay, and cultivated crops comprise over half of the Central Valley, much of which is considered prime agriculture or of statewide or local importance for farming (28,200 km2). Together, approximately one-third of this region is salt-contaminated (16%) or developed (11%). This confers a generation-based potential of 5713 - 7891 TWh y-1 and 2770 TWh y-1 for PV and CSP, respectively. As energy, food, and land are inextricably linked, our study shows how land favorable for renewable energy systems can be used more effectively in places where land is

  8. NAFTA and Mexico's Tax Policy Reform

    OpenAIRE

    Jorge Martinez-Vazquez; Duanje Chen

    2001-01-01

    The North American Free Trade Agreement (NAFTA) has had a significant effect on Mexico’s economy and institutions. The ongoing consideration of tax reform in Mexico requires an evaluation of the role of NAFTA in Mexico’s economy, including its tax structure; it also requires an assessment of the impact of the Mexico’s tax system on the trade and capital flows between Mexico and its NAFTA partners, the United States and Canada. Clearly, no good tax reform in Mexico can ignore the role of NAFTA...

  9. 76 FR 58840 - Central Valley Project Improvement Act; Refuge Water Management Plans

    Science.gov (United States)

    2011-09-22

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act; Refuge Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: To meet the requirements of the Central Valley Project Improvement Act of 1992 (CVPIA) and subsequent...

  10. Scientific Objectives of the Gulf of Mexico Gas Hydrate JIP Leg II Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E. (Chevron); Latham, T. (Chevron); McConnell, D. (AOA Geophysics); Frye, M. (Minerals Management Service); Hunt, J. (Minerals Management Service); Shedd, W. (Minerals Management Service); Shelander, D. (Schlumberger); Boswell, R.M. (NETL); Rose, K.K. (NETL); Ruppel, C. (USGS); Hutchinson, D. (USGS); Collett, T. (USGS); Dugan, B. (Rice University); Wood, W. (Naval Research Laboratory)

    2008-05-01

    The Gulf of Mexico Methane Hydrate Joint Industry Project (JIP) has been performing research on marine gas hydrates since 2001 and is sponsored by both the JIP members and the U.S. Department of Energy. In 2005, the JIP drilled the Atwater Valley and Keathley Canyon exploration blocks in the Gulf of Mexico to acquire downhole logs and recover cores in silt- and clay-dominated sediments interpreted to contain gas hydrate based on analysis of existing 3-D seismic data prior to drilling. The new 2007-2009 phase of logging and coring, which is described in this paper, will concentrate on gas hydrate-bearing sands in the Alaminos Canyon, Green Canyon, and Walker Ridge protraction areas. Locations were selected to target higher permeability, coarser-grained lithologies (e.g., sands) that have the potential for hosting high saturations of gas hydrate and to assist the U.S. Minerals Management Service with its assessment of gas hydrate resources in the Gulf of Mexico. This paper discusses the scientific objectives for drilling during the upcoming campaign and presents the results from analyzing existing seismic and well log data as part of the site selection process. Alaminos Canyon 818 has the most complete data set of the selected blocks, with both seismic data and comprehensive downhole log data consistent with the occurrence of gas hydrate-bearing sands. Preliminary analyses suggest that the Frio sandstone just above the base of the gas hydrate stability zone may have up to 80% of the available sediment pore space occupied by gas hydrate. The proposed sites in the Green Canyon and Walker Ridge areas are also interpreted to have gas hydrate-bearing sands near the base of the gas hydrate stability zone, but the choice of specific drill sites is not yet complete. The Green Canyon site coincides with a 4-way closure within a Pleistocene sand unit in an area of strong gas flux just south of the Sigsbee Escarpment. The Walker Ridge site is characterized by a sand

  11. Balancing urban development and endangered species: The coachella valley habitat conservation plan

    Science.gov (United States)

    Beatley, Timothy

    1992-01-01

    Habitat conservation plans (HCPs) permitted under Section 10(A) of the federal Endangered Species Act, have been increasingly used to overcome conflicts between urban development and species conservation. This article profiles one such HCP, the Coachella Valley (CA) Fringe-Toed Lizard Habitat Conservation Plan. The second HCP officially approved by the US Fish and Wildlife Service, the Coachella Valley case is frequently cited as a model for resolving conservation and development conflicts. The article begins with a discussion of the use of HCPs, and then provides a detailed discussion of Coachella Valley experience, its history, specific provisions, and success to date. A final section examines whether Coachella Valley does in fact represent a positive model. It is argued that the HCP has been less than fully successful and leaves unresolved a series of fundamental ethical and policy questions concerning the protection of endangered species.

  12. Geohydrology of the valley-fill aquifer in the Corning area, Steuben County, New York

    Science.gov (United States)

    Miller, Todd S.; Belli, J.L.; Allen, R.V.

    1982-01-01

    This report is the seventh in a series of 11 map sets depicting geohydrologic conditions in selected aquifers in upstate New York. Geohydrologic data are compiled on six maps at 1:24,000 scale. Together, the maps provide a comprehensive overview of a major valley-fill aquifer in southeastern Steuben County. The maps include surficial geology, geologic sections, water-infiltration potential of soil zone, aquifer thickness, potentiometric-surface elevations, and land use. The valley-fill deposits consist of alluvial silt, sand, and gravel, glacial-outwash (sand and gravel), till, and lacustrine silt and clay. The sand and gravel beds have relatively high permeabilities, whereas the till and silt deposits have relatively low permeabilities. Water-table conditions prevail in unconfined sand and gravel along the valley margin. Artesian conditions are found locally in sand and gravel confined under silt and clay in the middle of the valley. Recharge occurs nearly everywhere on the valley floor, but principally along the margin of the valley, where highly permeable land surface conditions exist, and runoff from the hillsides is concentrated. The use of land overlying the aquifer is a mixture of residential, commercial, agricultural, and industrial uses. (USGS)

  13. Conduction-band valley spin splitting in single-layer H-T l2O

    Science.gov (United States)

    Ma, Yandong; Kou, Liangzhi; Du, Aijun; Huang, Baibiao; Dai, Ying; Heine, Thomas

    2018-02-01

    Despite numerous studies, coupled spin and valley physics is currently limited to two-dimensional (2D) transition-metal dichalcogenides (TMDCs). Here, we predict an exceptional 2D valleytronic material associated with the spin-valley coupling phenomena beyond 2D TMDCs—single-layer (SL) H-T l2O . It displays large valley spin splitting (VSS), significantly larger than that of 2D TMDCs, and a finite band gap, which are both critically attractive for the integration of valleytronics and spintronics. More importantly, in sharp contrast to all the experimentally confirmed 2D valleytronic materials, where the strong valence-band VSS (0.15-0.46 eV) supports the spin-valley coupling, the VSS in SL H-T l2O is pronounced in its conduction band (0.61 eV), but negligibly small in its valence band (21 meV), thus opening a way for manipulating the coupled spin and valley physics. Moreover, SL H-T l2O possesses extremely high carrier mobility, as large as 9.8 ×103c m2V-1s-1 .

  14. Valley-momentum locking in a graphene superlattice with Y-shaped Kekulé bond texture

    Science.gov (United States)

    Gamayun, O. V.; Ostroukh, V. P.; Gnezdilov, N. V.; Adagideli, İ.; Beenakker, C. W. J.

    2018-02-01

    Recent experiments by Gutiérrez et al (2016 Nat. Phys. 12 950) on a graphene-copper superlattice have revealed an unusual Kekulé bond texture in the honeycomb lattice—a Y-shaped modulation of weak and strong bonds with a wave vector connecting two Dirac points. We show that this so-called ‘Kek-Y’ texture produces two species of massless Dirac fermions, with valley isospin locked parallel or antiparallel to the direction of motion. In a magnetic field B, the valley degeneracy of the B-dependent Landau levels is removed by the valley-momentum locking but a B-independent and valley-degenerate zero-mode remains.

  15. Environmental Assessment, Valentine Military Operations Area, Texax

    Science.gov (United States)

    1989-12-01

    1978. Control of Vibrations Caused by Blasting. Laboratorio National De Engenharia Civil, Lisboa, Portugal. Memoria 498. 11 p. Federal Air Quality...New Mexico Highway Department Project RS-f153(6) and FHP- 42-1(102) in Largo Creek Valley, Catron County, New Mexico, Gila National Forest. Laboratory

  16. Valleytronics in merging Dirac cones: All-electric-controlled valley filter, valve, and universal reversible logic gate

    Science.gov (United States)

    Ang, Yee Sin; Yang, Shengyuan A.; Zhang, C.; Ma, Zhongshui; Ang, L. K.

    2017-12-01

    Despite much anticipation of valleytronics as a candidate to replace the aging complementary metal-oxide-semiconductor (CMOS) based information processing, its progress is severely hindered by the lack of practical ways to manipulate valley polarization all electrically in an electrostatic setting. Here, we propose a class of all-electric-controlled valley filter, valve, and logic gate based on the valley-contrasting transport in a merging Dirac cones system. The central mechanism of these devices lies on the pseudospin-assisted quantum tunneling which effectively quenches the transport of one valley when its pseudospin configuration mismatches that of a gate-controlled scattering region. The valley polarization can be abruptly switched into different states and remains stable over semi-infinite gate-voltage windows. Colossal tunneling valley-pseudomagnetoresistance ratio of over 10 000 % can be achieved in a valley-valve setup. We further propose a valleytronic-based logic gate capable of covering all 16 types of two-input Boolean logics. Remarkably, the valley degree of freedom can be harnessed to resurrect logical reversibility in two-input universal Boolean gate. The (2 +1 ) polarization states (two distinct valleys plus a null polarization) reestablish one-to-one input-to-output mapping, a crucial requirement for logical reversibility, and significantly reduce the complexity of reversible circuits. Our results suggest that the synergy of valleytronics and digital logics may provide new paradigms for valleytronic-based information processing and reversible computing.

  17. Burrowing Owl - Palo Verde Valley [ds197

    Data.gov (United States)

    California Natural Resource Agency — These burrowing owl observations were collected during the spring and early summer of 1976 in the Palo Verde Valley, eastern Riverside County, California. This is an...

  18. Tuning Valley Polarization in a WSe_{2} Monolayer with a Tiny Magnetic Field

    Directory of Open Access Journals (Sweden)

    T. Smoleński

    2016-05-01

    Full Text Available In monolayers of semiconducting transition metal dichalcogenides, the light helicity (σ^{+} or σ^{-} is locked to the valley degree of freedom, leading to the possibility of optical initialization of distinct valley populations. However, an extremely rapid valley pseudospin relaxation (at the time scale of picoseconds occurring for optically bright (electric-dipole active excitons imposes some limitations on the development of opto-valleytronics. Here, we show that valley pseudospin relaxation of excitons can be significantly suppressed in a WSe_{2} monolayer, a direct-gap two-dimensional semiconductor with the exciton ground state being optically dark. We demonstrate that the already inefficient relaxation of the exciton pseudospin in such a system can be suppressed even further by the application of a tiny magnetic field of about 100 mT. Time-resolved spectroscopy reveals the pseudospin dynamics to be a two-step relaxation process. An initial decay of the pseudospin occurs at the level of dark excitons on a time scale of 100 ps, which is tunable with a magnetic field. This decay is followed by even longer decay (>1  ns, once the dark excitons form more complex pseudo-particles allowing for their radiative recombination. Our findings of slow valley pseudospin relaxation easily manipulated by the magnetic field open new prospects for engineering the dynamics of the valley pseudospin in transition metal dichalcogenides.

  19. Alumina+Silica+/-Germanium Alteration in Smectite-Bearing Marathon Valley, Endeavour Crater Rim, Mars

    Science.gov (United States)

    Mittlefehldt, D. W.; Gellert, R.; Van Bommel, S.; Arvidson, R. E.; Clark, B. C.; Ming, D. W.; Schroeder, C.; Yen, A. S.; Fox, V. K.; Farrand, W. H.; hide

    2016-01-01

    Mars Exploration Rover Opportunity has been exploring Mars for 12+ years, and is presently investigating the geology of a western rim segment of 22 kilometers diameter, Noachian- aged Endeavour crater. The Alpha Particle X-ray Spectrometer has determined the compositions of a pre-impact lithology, the Matijevic fm., and polymict impact breccias ejected from the crater, the Shoemaker fm. Opportunity is now investigating a region named Marathon Valley that cuts southwest-northeast through the central portion of the rim segment and provides a window into the lower stratigraphic record. (Geographic names used here are informal.) At the head of Marathon Valley, referred to here as Upper Marathon Valley, is a shallow, ovoid depression approximately 25×35 millimeters in size, named Spirit of Saint Louis. Layering inside Spirit of Saint Louis appears continuous with the Upper Marathon Valley rocks outside, indicating they are coeval. Spirit of Saint Louis is partly bounded by approximately 10-20 centimeters wide zone containing reddish altered rocks (red zone). Red zones also form prominent curvilinear features in Marathon Valley. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectra provide evidence for a really extensive Fe-Mg smectite in the Marathon Valley region, indicating distinct styles of aqueous alteration. The CRISM detections of smectites are based on metal-OH absorptions at approximately 2.3 and 2.4 micron that are at least two times the background noise level.

  20. HSIP Fire Stations in New Mexico

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Fire Stations in New Mexico Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their jobs is...

  1. Marquez Uranium Project, McKinley County, New Mexico: draft environmental impact statement

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Development and operation of an underground mine to remove uranium deposits from the Canon de Marquez in McKinley County, New Mexico is proposed by the Tennessee Valley Authority (TVA). Uranium mined from the area would be used by TVA to supply fuel for its nuclear plants, ensuring a continued supply of inexpensive electricity and a source of employment for the population of the TVA's region. In addition, the mine would employ 55 to 120 persons and generate $21.1 million in state and local taxes during its lifetime. Construction and operation of mine facilities would alter land uses on 120 acres of wildlife habitat, alter the topography of the area in the vicinity of the proposed pond and rock pile sites, depress groundwater levels in the Westwater Canyon Member of the Morrison Formation in the vicinity of the mine, degrade groundwater and air quality in the vicinity of the mine, decrease plant and animal species at the site, degrade water quality in creeks downstream of the mine, and increase ambient noise levels. All negative impacts would be confined to the life of the mine, since reclamation activities would return the mine area to premining conditions

  2. Groundwater quality in the Indian Wells Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Indian Wells Valley is one of the study areas being evaluated. The Indian Wells study area is approximately 600 square miles (1,554 square kilometers) and includes the Indian Wells Valley groundwater basin (California Department of Water Resources, 2003). Indian Wells Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lake beds in the lower parts of the valley. Land use in the study area is approximately 97.0 percent (%) natural, 0.4% agricultural, and 2.6% urban. The primary natural land cover is shrubland. The largest urban area is the city of Ridgecrest (2010 population of 28,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from the Sierra Nevada to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and direct infiltration from irrigation and septic systems. The primary sources of discharge are pumping wells and evapotranspiration near the dry lakebeds. The primary aquifers in the Indian Wells study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in

  3. A Route to Permanent Valley Polarization in Monolayer MoS2

    KAUST Repository

    Singh, Nirpendra

    2016-10-24

    Realization of permanent valley polarization in Cr-doped monolayer MoS2 is found to be unfeasible because of extended moment formation. Introduction of an additional hole is suggested as a viable solution. V-doped monolayer MoS2 is demonstrated to sustain permanent valley polarization and therefore can serve as a prototype material for valleytronics.

  4. Inland valley research in sub-Saharan Africa; priorities for a regional consortium

    NARCIS (Netherlands)

    Jamin, J.Y.; Andriesse, W.; Thiombiano, L.; Windmeijer, P.N.

    1996-01-01

    These proceedings are an account of an international workshop in support of research strategy development for the Inland Valley Consortium in sub-Saharan Africa. This consortium aims at concerted research planning for rice-based cropping systems in the lower parts of inland valleys. The Consortium

  5. Topological valley-chiral edge states of Lamb waves in elastic thin plates

    Science.gov (United States)

    Wang, Jian; Mei, Jun

    2018-05-01

    We investigate the nontrivial topology of the band structure of Lamb waves in a thin phononic crystal plate. When inversion symmetry is broken, a valley pseudospin degree of freedom is formed around K and K‧ valleys for the A0 Lamb mode, which is decoupled from the S0 and SH0 modes in the low-frequency regime. Chiral edge states are explicitly demonstrated, which are immune to defects and exhibit unidirectional transport behaviors when intervalley scattering is weak. The quantum valley Hall effect is thus simulated in a simple way in the context of Lamb waves.

  6. New Mexico Higher Education Department Annual Report, 2016

    Science.gov (United States)

    New Mexico Higher Education Department, 2016

    2016-01-01

    The New Mexico Higher Education Department strives to bring leadership, guidance, and assistance to New Mexico's higher education stakeholders. The HED is committed to promoting best practices, institutional fiscal responsibility, and student achievement. Everything the agency does is through the lens of supporting New Mexico's higher education…

  7. Changes in active eolian sand at northern Coachella Valley, California

    Science.gov (United States)

    Katra, Itzhak; Scheidt, Stephen; Lancaster, Nicholas

    2009-04-01

    Climate variability and rapid urbanization have influenced the sand environments in the northern Coachella Valley throughout the late 20th century. This paper addresses changes in the spatial relationships among different sand deposits at northern Coachella Valley between two recent time periods by using satellite data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The approach employed here, involving multispectral thermal infrared (TIR) data and spectral mixture analysis, has shown that the major sand deposits can be spatially modeled at northern Coachella Valley. The "coarse-grained (quartz-rich) sand" deposit is associated with active eolian sand, and the "mixed sandy soil" and "fine-grained (quartz-rich) sand" deposits are associated with inactive eolian sand. The fractional abundance images showed a significant decrease between 2000 and 2006 in the percentage of active sand in the major depositional area for fluvial sediment, the Whitewater River, but also in two downwind areas: the Whitewater and Willow Hole Reserves. The pattern of the active sand appears to be related to variations in annual precipitation (wet and dry years) and river discharge in the northern Coachella Valley. We suggest here that recent human modifications to the major watercourses that supply sand affect the capability of fluvial deposition areas to restore sediments over time and consequently the responses of the sand transport system to climate change, becoming more sensitive to dry years where areas of active sand may shrink, degrade, and/or stabilize faster. The approach utilized in this study can be advantageous for future monitoring of sand in the northern Coachella Valley for management of these and similar environments.

  8. Motivation Factors for Female Entrepreneurship in Mexico

    Directory of Open Access Journals (Sweden)

    Martha Cantú Cavada

    2017-09-01

    Full Text Available Objective: The objective of this paper is to analyse motivation factors for female entrepreneurship in Mexico. In the proposed article, the authors discuss the factors which compelled women to start their enterprises in Mexico. Research Design & Methods: Based on in-depth interviews with female entrepreneurs and entrepreneurship experts, the authors show which factors motivated women to start their own business in Mexico. Findings: The study proves that women in Mexico are motivated by a combination of push and pull factors, where the majority of the factors are pull factors. The findings of the study help to conclude that female entrepreneurship development is influenced by different factors including the entrepreneurs’ personal traits, social and economic factors. Due to their conservative traditional attitude, risk adverse tendency, and non-cooperation of family members, etc. women entrepreneurs are sometimes deterred to start a business in Mexico. Implications & Recommendations: It is necessary to raise the awareness of different factors that promote female entrepreneurship in Mexico. Governmental programmes which support female entrepreneurship, business incubators, and networking could be very helpful for women when starting their own business. Contribution & Value Added: The originality of this work lies in studying motivational factors for female entrepreneurship in Mexico. The Mexican society faces a big revolution towards female entrepreneurship. Based on the change of family structure and traditions, women nowadays are having more opportunities to develop as entrepreneurs.

  9. Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene.

    Science.gov (United States)

    Hunt, B M; Li, J I A; Zibrov, A A; Wang, L; Taniguchi, T; Watanabe, K; Hone, J; Dean, C R; Zaletel, M; Ashoori, R C; Young, A F

    2017-10-16

    The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers.The phase diagram of bilayer graphene at high magnetic fields has been an outstanding question, with orders possibly between multiple internal quantum degrees of freedom. Here, Hunt et al. report the measurement of the valley and orbital order, allowing them to directly reconstruct the phase diagram.

  10. Shallow Sedimentary Structure of the Brahmaputra Valley Constraint from Receiver Functions Analysis

    Science.gov (United States)

    Saikia, Sowrav; Chopra, Sumer; Baruah, Santanu; Singh, Upendra K.

    2017-01-01

    In this study, receiver functions from ten Broadband seismograph stations on Cenozoic sediment formations of Brahmaputra valley and its neighboring region in northeastern part of India are determined. Receiver function traces from this region show delay in peak by 1-2.5 s and associated minor peaks with the direct P-phase peak. Based on such observation, we try to image sedimentary structure of the Brahmaputra valley plain, adjacent Shillong plateau and Himalayan foredeep region. An adapted hybrid global waveform inversion technique has been applied to extract sedimentary basin structure beneath each site. The sedimentary cover of the basin is about 0.5-6.5 km thick across the valley, 0.5-1.0 km on Shillong plateau and 2.0-5.0 km in nearby foredeep region. We have found that sedimentary thickness increases from SW to NE along the Brahmaputra valley and towards the Eastern Himalayan syntaxes. The estimated sediment thickness and S wave velocity structure agree well with the results of previous active source, gravity, and deep borehole studies carried out in this region. The thick crustal low velocity sediment cover in Brahmaputra valley is expected to amplify ground motions during earthquakes and therefore important for seismic hazard assessment of the region.

  11. Doing Business in Mexico

    OpenAIRE

    Zimmermann, Thomas A.

    2002-01-01

    On 1 July 2001, a far-reaching free trade agreement between the EFTA States and Mexico entered into force. ”Doing Business in Mexico” provides targeted assistance to Swiss Small and Medium-Sized Enterprises (SME) that wish to tap the potential of Mexico as both an export destination and investment location. This comprehensive guide contains information and advice on market research, market entry, and investment in this fascinating country. Part I introduces the reader to this fascinating ...

  12. New Mexico HUC-8 Boundaries - 2013

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set is a complete digital hydrologic unit boundary layer to the Subbasin (8-digit) 8th level for the State of New Mexico. This data set consists of...

  13. New Mexico HUC-10 Boundaries - 2013

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set is a complete digital hydrologic unit boundary layer to the watershed (10-digit) 10th level for the State of New Mexico. This data set consists of...

  14. 76 FR 45212 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Science.gov (United States)

    2011-07-28

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... proposing to approve San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) Rule 3170... the environment. San Joaquin Valley Unified Air Pollution Control District SJVUAPCD is an extreme...

  15. 27 CFR 9.174 - Yadkin Valley.

    Science.gov (United States)

    2010-04-01

    ...”. (b) Approved maps. The appropriate maps for determining the boundaries of the Yadkin Valley...-Salem, N.C.; VA; Tenn. (1953, Limited Revision 1962), and, (2) Charlotte, North Carolina; South Carolina... North Carolina within Wilkes, Surry, Yadkin and portions of Stokes, Forsyth, Davidson, and Davie...

  16. New Mexico Known Mineral Deposit Areas

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset contains all Known Mineral Deposit Areas in the state of New Mexico. It is in a vector digital structure digitized from a 1:500,000 scale map of the...

  17. Influenza-like illness in Mexico and the United States

    Indian Academy of Sciences (India)

    2009-04-13

    First page Back Continue Last page Graphics. Influenza-like illness in Mexico and the United States. Mexico. First case April 13, 2009 in Mexico. By May 3, 2,498 suspected cases,165 deaths in 31 of 32 States in Mexico. The USA. 24 April 2009. The US reported 7 confirmed human cases of Influenza A/H1N1. Five cases in ...

  18. 78 FR 59628 - Importation of Potatoes From Mexico

    Science.gov (United States)

    2013-09-27

    ... Mexico AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Proposed rule. SUMMARY: We are... importation of fresh potatoes (Solanum tuberosum L.) from Mexico into the United States. As a condition of... plant protection organization (NPPO) of Mexico would have to provide a bilateral workplan to the Animal...

  19. Baseline risk assessment of ground water contamination at the Monument Valley Uranium Mill Tailings Site, Cane Valley, Arizona. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This baseline risk assessment evaluates potential impact to public health or the environment from ground water contamination at the former uranium mill processing site in Cane Valley near Monument Valley, Arizona. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project has relocated and stabilized this site`s tailings and other contaminated material in a disposal cell at Mexican Hat, Utah. The second phase of the UMTRA Project is to evaluate ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project that evaluates potential health and environmental risks. It will help determine the approach required to address contaminated ground water at the site.

  20. Baseline risk assessment of ground water contamination at the Monument Valley Uranium Mill Tailings Site, Cane Valley, Arizona. Revision 1

    International Nuclear Information System (INIS)

    1994-08-01

    This baseline risk assessment evaluates potential impact to public health or the environment from ground water contamination at the former uranium mill processing site in Cane Valley near Monument Valley, Arizona. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project has relocated and stabilized this site's tailings and other contaminated material in a disposal cell at Mexican Hat, Utah. The second phase of the UMTRA Project is to evaluate ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project that evaluates potential health and environmental risks. It will help determine the approach required to address contaminated ground water at the site

  1. Site-wide remedial alternative development in Bear Creek Valley, Oak Ridge Reservation

    International Nuclear Information System (INIS)

    Anderson, M.

    1995-07-01

    This paper presents a case study of an environmental restoration project at a major mixed waste site that poses unique challenges to remediation efforts. Bear Creek Valley is located immediately west of the Y-12 Plant on the Oak Ridge Reservation (ORR) in Oak Ridge, Tennessee. The Y-12 Plant was built in 1943 as part of the Manhattan Project, with its original mission being electromagnetic separation of uranium. Since being completed, the Y-12 Plant has also been used for chemical processing of uranium and lithium compounds as well as precision fabrication of components containing these and other materials. Wastes containing radionuclides, metals, chlorinated solvents, oils, coolants, polychlorinated biphenyis (PCBs), and others were disposed of in large quantities at Bear Creek Valley as a result of manufacturing operations at the Y-12 Plant. The Bear Creek Valley feasibility study is using innovative strategies to efficiently and thoroughly consider the information available regarding Bear Creek Valley and process options that could be combined into its remedial alternatives

  2. Infilling and flooding of the Mekong River incised valley during deglacial sea-level rise

    Science.gov (United States)

    Tjallingii, Rik; Stattegger, Karl; Wetzel, Andreas; Van Phach, Phung

    2010-06-01

    The abrupt transition from fluvial to marine deposition of incised-valley-fill sediments retrieved from the southeast Vietnamese shelf, accurately records the postglacial transgression after 14 ka before present (BP). Valley-filling sediments consist of fluvial mud, whereas sedimentation after the transgression is characterized by shallow-marine carbonate sands. This change in sediment composition is accurately marked in high-resolution X-ray fluorescence (XRF) core scanning records. Rapid aggradation of fluvial sediments at the river mouth nearly completely filled the Mekong incised valley prior to flooding. However, accumulation rates strongly reduced in the valley after the river-mouth system flooded and stepped back. This also affected the sediment supply to deeper parts of the southeast Vietnamese shelf. Comparison of the Mekong valley-filling with the East Asian sea-level history of sub- and inter-tidal sediment records shows that the transgressive surface preserved in the incised-valley-fill records is a robust sea-level indicator. The valley was nearly completely filled with fluvial sediments between 13.0 and 9.5 ka BP when sea-level rose rather constantly with approximately 10 mm/yr, as indicated by the East Asian sea-level record. At shallower parts of the shelf, significant sediment reworking and the establishment of estuarine conditions at the final stage of infilling complicates accurate dating of the transgressive surface. Nevertheless, incised-valley-fill records and land-based drill sites indicate a vast and rapid flooding of the shelf from the location of the modern Vietnamese coastline to the Cambodian lowlands between 9.5 ka and 8.5 ka BP. Fast flooding of this part of the shelf is related with the low shelf gradient and a strong acceleration of the East Asian sea-level rise from 34 to 9 meter below modern sea level (mbsl) corresponding to the sea-level jump of melt water pulse (MWP) 1C.

  3. [Food security in Mexico].

    Science.gov (United States)

    Urquía-Fernández, Nuria

    2014-01-01

    An overview of food security and nutrition in Mexico is presented, based on the analysis of the four pillars of food security: availability, access, utilization of food, and stability of the food supply. In addition, the two faces of malnutrition in Mexico were analyzed: obesity and undernourishment. Data were gathered from the food security indicators of the United Nations's Food and Agriculture Organization, from the Mexican Scale of Food Security, and from the National Health and Nutrition Survey. Mexico presents an index of availability of 3 145 kilocalories per person per day, one of the highest indexes in the world, including both food production and imports. In contrast, Mexico is affected by a double burden of malnutrition: whereas children under five present 14% of stunt, 30% of the adult population is obese. Also, more than 18% of the population cannot afford the basic food basket (food poverty). Using perception surveys, people reports important levels of food insecurity, which concentrates in seven states of the Mexican Federation. The production structure underlying these indicators shows a very heterogeneous landscape, which translates in to a low productivity growth across the last years. Food security being a multidimensional concept, to ensure food security for the Mexican population requires a revision and redesign of public productive and social policies, placing a particular focus on strengthening the mechanisms of institutional governance.

  4. Summary Robert Noyce and the invention of Silicon Valley

    CERN Document Server

    2014-01-01

    This work offers a summary of the book "THE MAN BEHIND THE MICROCHIP: Robert Noyce and the Invention of Silicon Valley""by Leslie Berlin.The Man behind the Microchip is Leslie Berlin's first book. This author is project historian for the Silicon Valley Archives, a division of the Stanford University Department of Special Collections. This book tells the story of a giant of the high-tech industry: the multimillionaire Bob Noyce. This co-founder of Fairchild Semiconductor and Intel co-invented the integrated circuit which became the electronic heart of every modern computer, automobile, advance

  5. Birds of the St. Croix River valley: Minnesota and Wisconsin

    Science.gov (United States)

    Faanes, Craig A.

    1981-01-01

    The St. Croix River Valley encompasses nearly 11,550 km2 in east-central Minnesota and northwestern Wisconsin. A wide range of habitats are available for birds including upland oak, lowland deciduous, maple-basswood, lowland and upland coniferous forests, natural basin wetlands, and grasslands. Situated in the north-central region of the United States, the valley is a biological 'crossroads' for many species. Because of the mixed affinities of plant communities, the valley includes the northern and southern range limits for a number of species. Also, because the valley lies near the forest-prairie transition zone, many typical western breeding species (e.g. pintail, western meadowlark, yellow-headed blackbird) breed in proximity to typical eastern species such as tufted titmouse, eastern meadowlark, and cardinal. From 1966 to 1980, I conducted extensive surveys of avian distribution and abundance in the St. Croix River Valley. I have supplemented the results of these surveys with published and unpublished observations contributed by many ornithologists. These additional data include compilations from Christmas Bird Counts sponsored by the National Audubon Society and from the Breeding Bird Survey coordinated by the U.S. Fish and Wildlife Service. Three hundred fourteen species have been recorded in the study area; data are presented on the migration period, nesting season distribution, winter distribution, relative abundance, and habitat use of each species. Recognizing the uniqueness of the area, and its importance not only to wildlife but also to man, the U.S. Congress designated the St. Croix a National Scenic Riverway. This action provided a considerable degree of protection to lands along and directly adjacent to the river. Unfortunately, no similar legal measure exists to protect lands away from the river. With the exception of the northern quarter of the St. Croix River Valley, agricultural interests have made significant inroads into the habitat base. The

  6. Analysis of overdeepened valleys using the digital elevation model of the bedrock surface of Northern Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, P.

    2010-11-15

    Based on surface and borehole information, together with pre-existing regional and local interpretations, a 7,150 square kilometre Raster Digital Elevation Model (DEM) of the bedrock surface of northern Switzerland was constructed using a 25 m cell size. This model represents a further important step in the understanding of Quaternary sediment distribution and is open to a broad field of application and analysis, including hydrogeological, geotechnical and geophysical studies as well as research in the field of Pleistocene landscape evolution. An analysis of the overdeepened valleys in the whole model area and, more specifically in the Reuss area, shows that, in most cases, overdeepening is restricted to the areas covered by the Last Glaciation Maximum (LGM). However, at various locations relatively narrow overdeepened valleys outreach the tongue basins and the LGM ice shield limits. Therefore, an earlier and further-reaching glacial event has probably contributed significantly to the overdeepening of these valleys. No significant overdeepening has been identified downstream of Boettstein (Aare) and Kaiserstuhl (Rhine), although the ice extended considerably further downstream, at least during the most extensive glaciation. Except for the bedrock between Brugg and Boettstein, no overdeepened valleys are found significantly north of the outcrop of Mesozoic limestone of the Folded and Tabular Jura. A detailed analysis of the Reuss area shows that the Lake and Suhre valleys are separated from the Emmen-Gisikon Reuss valley basin by a significant bedrock barrier. The individual bedrock valleys are divided into several sub-basins, indicating a multiphase evolution of the valleys. Some of the swells or barriers separating the sub-basins coincide with known late LGM retreat stages. In the Suhre valley, an old fluvial valley floor with restricted overdeepened sections is documented. (author)

  7. Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12

    Science.gov (United States)

    Berger, David L.; Mayers, C. Justin; Garcia, C. Amanda; Buto, Susan G.; Huntington, Jena M.

    2016-07-29

    The Diamond Valley flow system consists of six hydraulically connected hydrographic areas in central Nevada. The general down-gradient order of the areas are southern and northern Monitor Valleys, Antelope Valley, Kobeh Valley, Stevens Basin, and Diamond Valley. Groundwater flow in the Diamond Valley flow system terminates at a large playa in the northern part of Diamond Valley. Concerns relating to continued water-resources development of the flow system resulted in a phased hydrologic investigation that began in 2005 by the U.S. Geological Survey in cooperation with Eureka County. This report presents the culmination of the phased investigation to increase understanding of the groundwater resources of the basin-fill aquifers in the Diamond Valley flow system through evaluations of groundwater chemistry and budgets. Groundwater chemistry was characterized using major ions and stable isotopes from groundwater and precipitation samples. Groundwater budgets accounted for all inflows, outflows, and changes in storage, and were developed for pre-development (pre-1950) and recent (average annual 2011–12) conditions. Major budget components include groundwater discharge by evapotranspiration and groundwater withdrawals; groundwater recharge by precipitation, and interbasin flow; and storage change.

  8. 76 FR 56471 - Meeting of the John H. Chafee Blackstone River Valley National Heritage Corridor Commission

    Science.gov (United States)

    2011-09-13

    ...] Meeting of the John H. Chafee Blackstone River Valley National Heritage Corridor Commission AGENCY: National Heritage Corridor Commission, John H. Chafee Blackstone River Valley, National Park Service... Advisory Committee Act, 5 U.S.C. Appendix, that the John H. Chafee Blackstone River Valley National...

  9. Rift Valley Fever.

    Science.gov (United States)

    Hartman, Amy

    2017-06-01

    Rift Valley fever (RVF) is a severe veterinary disease of livestock that also causes moderate to severe illness in people. The life cycle of RVF is complex and involves mosquitoes, livestock, people, and the environment. RVF virus is transmitted from either mosquitoes or farm animals to humans, but is generally not transmitted from person to person. People can develop different diseases after infection, including febrile illness, ocular disease, hemorrhagic fever, or encephalitis. There is a significant risk for emergence of RVF into new locations, which would affect human health and livestock industries. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Current hot spot in the spin-valley blockade in carbon nanotubes

    Science.gov (United States)

    Széchenyi, Gábor; Pályi, András

    2013-12-01

    We present a theoretical study of the spin-valley blockade transport effect in a double quantum dot defined in a straight carbon nanotube. We find that intervalley scattering due to short-range impurities completely lifts the spin-valley blockade and induces a large leakage current in a certain confined range of the external magnetic field vector. This current hot spot emerges due to different effective magnetic fields acting on the spin-valley qubit states of the two quantum dots. Our predictions are compared to a recent measurement [F. Pei , Nat. Nanotech.1748-338710.1038/nnano.2012.160 7, 630 (2012)]. We discuss the implications for blockade-based schemes for qubit initialization/readout and motion sensing of nanotube-based mechanical resonators.

  11. Health technology assessment in Mexico.

    Science.gov (United States)

    Gómez-Dantés, Octavio; Frenk, Julio

    2009-07-01

    The history of health technology assessment (HTA) in Mexico is examined, starting with the efforts to incorporate this topic into the policy agenda and culminating with the recent creation of a specialized public agency. Information was gathered through a bibliographic search and interviews with actors involved in HTA in Mexico. HTA efforts were developed in Mexico since the mid-1980s with the participation both of academics and of policy makers, a relationship that eventually led to the creation of the Center for Technological Excellence within the Ministry of Health. Institutionalization of HTA in resource-constrained settings requires the development of a critical mass of researchers involved in this field, the implementation of information efforts, and the establishment of strong relationships between HTA experts and policy makers.

  12. Mexico On A Criminal Traffic Scenario

    Directory of Open Access Journals (Sweden)

    M. P. Moloeznik

    2017-01-01

    Full Text Available The article describes the problem of organized crime in modern Mexico. It addresses the activities of criminal clans, which profoundly evolved since the 1930s. The USMexican extensive border length and the stable demand for drugs in the United States leads to the continuous flow of illegal migrants and drugs from Mexico to the US and American firearms back to Mexico. First, the authors address the issue of interconnectedness of crime in the neighboring countries. Second, they describe the geographical distribution of crime activity. It shows the influence of organized crime on the political life oin Mexico and ways of its adaptation to law enforcement pressure, namely division and disaggregation. The authors state that the fight against organized crime was ineffective in Mexico in 2006-2012, because it ignored political and cultural realities, it used exclusively force and almost did not involve civil society. In addition, it only increased the level of violence in the country and contributed to the growth of corruption in the ranks of law enforcement. Moreover, it increased the level of violence in the country and contributed to the growth of corruption in the ranks of law enforcement. Many of its components had a pronounced «pre-election» character, aimed at attracting the voter with the promise of an «early and decisive victory» over criminals. The article proposes new approach to the problem of organized crime in Mexico. To start with, government should refuse to use unilateral, as well as politicized and opportunistic actions. The involvement of civic society is of ultimate importance.

  13. Evidence for slow late-glacial ice retreat in the upper Rangitata Valley, South Island, New Zealand

    Science.gov (United States)

    Shulmeister, J.; Fink, D.; Winkler, S.; Thackray, G. D.; Borsellino, R.; Hemmingsen, M.; Rittenour, T. M.

    2018-04-01

    A suite of cosmogenic radionuclide ages taken from boulders on lateral and latero-terminal moraines in the Rangitata Valley, eastern South Island, New Zealand demonstrates that relatively thick ice occupied valley reaches inland of the Rangitata Gorge until c. 21 ka. Thereafter ice began to thin, and by c. 17 ka it had retreated 33 km up-valley of the Rangitata Gorge to the Butler-Brabazon Downs, a structurally created basin in the upper Rangitata Valley. Despite its magnitude, this retreat represents a minor ice volume reduction from 21 ka to 17 ka, and numerous lateral moraines preserved suggest a relatively gradual retreat over that 4 ka period. In contrast to records from adjacent valleys, there is no evidence for an ice-collapse at c. 18 ka. We argue that the Rangitata record constitutes a more direct record of glacial response to deglacial climate than other records where glacial dynamics were influenced by proglacial lake development, such as the Rakaia Valley to the North and the major valleys in the Mackenzie Basin to the south-west. Our data supports the concept of a gradual warming during the early deglaciation in the South Island New Zealand.

  14. Fleas and lice of mammals in New Mexico

    Science.gov (United States)

    Paulette L. Ford; Richard A. Fagerlund; Donald W. Duszynski; Paul J. Polechla

    2004-01-01

    All available records are compiled for three orders of ectoparasites of mammals in New Mexico: fleas (Siphonaptera), sucking lice (Anoplura), and chewing lice (Mallophaga). We have drawn from records at the University of New Mexico's Museum of Southwestern Biology, the Vector Control Program of the New Mexico Environment Department, the Environmental Health...

  15. 1985年9月19日メキシコ地震に関する研究 I : 地盤震動特性と被害との関係について

    OpenAIRE

    正木, 和明

    1989-01-01

    The damage in Mexico city during the Mexico Earthquake of September 19,1985 was studied in relation to seismic characteristics of soils in Mexico Valley. Mexico city is nowadays one of the biggest cities in the world with population of about 18 million. A sudden increase in population since 1940 caused a rapid expantion of urban area to the Lake Zone composed of extremely soft sediments of Lake Texcoco. Damages during the earthquake concentrated in this area. Microtremor measurements and spec...

  16. Where Do Mexico and Chile Stand on Inclusive Education? Short Title: Inclusion in Mexico and Chile

    Science.gov (United States)

    García-Cedillo, Ismael; Romero-Contreras, Silvia; Ramos-Abadie, Liliana

    2015-01-01

    This paper discusses the background, current situation and challenges of educational integration and inclusive education in Mexico and Chile. These countries obtained similar low results on the academic achievement of their students (Mexico last and Chile second last) among OECD countries; and above average scores, among Latin-American countries.…

  17. Predicting the valley physics of silicon quantum dots directly from a device layout

    Science.gov (United States)

    Gamble, John King; Harvey-Collard, Patrick; Jacobson, N. Tobias; Bacewski, Andrew D.; Nielsen, Erik; Montaño, Inès; Rudolph, Martin; Carroll, Malcolm S.; Muller, Richard P.

    Qubits made from electrostatically-defined quantum dots in Si-based systems are excellent candidates for quantum information processing applications. However, the multi-valley structure of silicon's band structure provides additional challenges for the few-electron physics critical to qubit manipulation. Here, we present a theory for valley physics that is predictive, in that we take as input the real physical device geometry and experimental voltage operation schedule, and with minimal approximation compute the resulting valley physics. We present both effective mass theory and atomistic tight-binding calculations for two distinct metal-oxide-semiconductor (MOS) quantum dot systems, directly comparing them to experimental measurements of the valley splitting. We conclude by assessing these detailed simulations' utility for engineering desired valley physics in future devices. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. The authors gratefully acknowledge support from the Sandia National Laboratories Truman Fellowship Program, which is funded by the Laboratory Directed Research and Development (LDRD) Program.

  18. 77 FR 68783 - Prospective Grant of Co-Exclusive License: Veterinary Vaccines for Rift Valley Fever Virus

    Science.gov (United States)

    2012-11-16

    ... Grant of Co-Exclusive License: Veterinary Vaccines for Rift Valley Fever Virus AGENCY: Centers for... Valley Fever Virus Utilizing Reverse Genetics,'' US Provisional Application 61/042,987, filed 4/7/2008, entitled ``Recombinant Rift Valley Fever (RVF) Viruses and Method of Use,'' PCT Application PCT/US2008...

  19. 75 FR 22775 - Copper Valley Electric Association; Notice of Scoping Meeting and Soliciting Scoping Comments for...

    Science.gov (United States)

    2010-04-30

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-000] Copper Valley....: 13124-000. c. Applicant: Copper Valley Electric Association. d. Name of Project: Allison Lake Project. e.... 791(a)-825(r). g. Applicant Contact: Robert A. Wilkinson, CEO, Copper Valley Electric Association, P.O...

  20. First report of myxomatosis in Mexico.

    Science.gov (United States)

    Licón Luna, R M

    2000-07-01

    An outbreak of myxomatosis occurred between September and October 1993 on a rabbit farm in Punta Colnett (Ensenada, Baja California in northwestern Mexico, Transpeninsular Highway, km 128) and was confirmed by the Mexico-USA Commission for Prevention of Foreign Diseases of Animals (CPA). This represents the first officially confirmed case of the disease in Mexico. Like the cases in California (USA), the brush rabbit (Sylvilagus bachmani) seems to be the carrier of the virus, since serum samples from wild rabbits from different areas of the peninsula of Baja California were found to contain antibodies against the myxoma virus.