Science.gov

Sample records for las separaciones cromatograficas

  1. Las Vegas

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of Las Vegas, NV was acquired on August, 2000 and covers an area 42 km (25 miles) wide and 30 km (18 miles) long. The image displays three bands of the reflected visible and infrared wavelength region, with a spatial resolution of 15 m. McCarran International Airport to the south and Nellis Air Force Base to the NE are the two major airports visible. Golf courses appear as bright red areas of worms. The first settlement in Las Vegas (which is Spanish for The Meadows) was recorded back in the early 1850s when the Mormon church, headed by Brigham Young, sent a mission of 30 men to construct a fort and teach agriculture to the Indians. Las Vegas became a city in 1905 when the railroad announced this city was to be a major division point. Prior to legalized gambling in 1931, Las Vegas was developing as an agricultural area. Las Vegas' fame as a resort area became prominent after World War II. The image is located at 36.1 degrees north latitude and 115.1 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Pease, P. B.

    1989-01-01

    Version 4.1 of LAS provides flexible framework for algorithm development and processing and analysis of image data. Over 500,000 lines of code enable image repair, clustering, classification, film processing, geometric registration, radiometric correction, and manipulation of image statistics.

  3. Las Campanas Stellar Library

    NASA Astrophysics Data System (ADS)

    Chilingarian, Igor; Zolotukhin, Ivan; Beletsky, Yuri; Worthey, Guy

    2015-08-01

    Stellar libraries are fundamental tools required to understand stellar populations in star clusters and galaxies as well as properties of individual stars. Comprehensive libraries exist in the optical domain, but the near-infrared (NIR) domain stays a couple of decades behind. Here we present the Las Campanas Stellar Library project aiming at obtaining high signal-to-noise intermediate-resolution (R=8000) NIR spectra (0.83<λ<2.5μm) for a sample of 1200 stars in the Southern sky using the Folded-port InfraRed Echelette spectrograph at the 6.5-m Magellan Baade telescope. We developed a dedicated observing strategy and customized the telescope control software in order to achieve the highest possible level of data homogeniety. As of 2015, we observed about 600 stars of all spectral types and luminosity classes making our library the largest homogeneous collection of stellar spectra covering the entire NIR domain. We also re-calibrated in flux and wavelength the two existing optical stellar libraries, INDO-US and UVES-POP and followed up about 400 non-variable stars in the NIR in order to get complete optical-NIR coverage. Worth mentioning that our current sample includes about 80 AGB stars and a few dozens of bulge/LMC/SMC stars.

  4. The Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Lu, Yun-Chi; Irani, Fred M.

    1991-01-01

    The Land Analysis System (LAS) is an interactive software system, available in the public domain, for the analysis, display, and management of multispectral and other digital image data. The system was developed to support earth sciences research and development activities. LAS provides over 240 applications functions and utilities, a flexible user interface, complete on-line and hardcopy documentation, extensive image data file management, reformatting, and conversion utilities, and high level device independent access to image display hardware. The capabilities are summarized of the latest release of the system (version 5). Emphasis is given to the system portability and the isolation of hardware and software dependencies in this release.

  5. EMPACT: THE LAS VEGAS INTERAGENCY PILOT PROGRAM

    EPA Science Inventory

    ENPACT: The Las Vegas Interagency Pilot Project

    The Las Vegas Interagency Pilot Project of the EMPACT program has involved eleven efforts. These efforts are described in brief on the poster presentation. They include: Las Vegas Environmental Monitoring Inventory, the Qual...

  6. Calidad del aire interior en las escuelas

    EPA Pesticide Factsheets

    EPA ha desarrollado el Programa de Herramientas de Calidad del Aire Interior para las Escuelas para reducir la exposición a los contaminantes ambientales en las mismas a través de la adopción voluntaria de las prácticas para manejar la calidad del aire int

  7. Leaving Las Vegas: Exposure to Las Vegas and risk of suicide.

    PubMed

    Wray, Matt; Miller, Matthew; Gurvey, Jill; Carroll, Joanna; Kawachi, Ichiro

    2008-12-01

    Residents of Las Vegas, Nevada have much higher suicide rates than residents of other metropolitan counties in the USA. Whether the risk of suicide among visitors to Las Vegas is also significantly elevated has been difficult to assess because person-time denominator information is not available. We used a case-control design to examine the association between exposure to Las Vegas and risk of suicide expressed as mortality odds ratios. We conceptualized four different types of potential suicide risk with respect to Las Vegas: (1) risk of suicide among usual residents of Las Vegas ("chronic risk"), (2) risk of suicide among temporary visitors to Las Vegas ("acute risk"), (3) risk of suicide among Las Vegas residents visiting elsewhere ("leaving Las Vegas risk"), and (4) risk of suicide among travelers in general ("traveler risk"). Controlling for age, gender, marital status, and year effects, the odds of suicide among Las Vegas residents was at least 50% greater than among residents elsewhere in each of the three decades we observed. Visitors to Las Vegas were at double the risk compared to those who stayed in their home county. Leaving Las Vegas was associated with a greater than 20% reduction in risk for suicide. Traveling to Las Vegas is associated with a twofold increase in risk compared to traveling elsewhere. We discuss three possible theoretical frameworks to help explain our observed results: ecological effects, whereby social factors unique to Las Vegas, or uniquely amplified in Las Vegas, result in increased risk to both residents and visitors; selection effects whereby those predisposed to suicide disproportionately choose Las Vegas to reside in and visit; and contagion effects, whereby high numbers of suicides tend to lead to even greater numbers over time, as people emulate the suicides of others. We compare our empirical evidence for each of the effects with existing sociological and historical scholarship on Las Vegas.

  8. Acerca de las ratas y los ratones

    EPA Pesticide Factsheets

    Hay muchas especies de roedores, entre ellas, la ardilla, la ardilla listada, el castor, el perro de la pradera, la rata y el ratón. Se puede ver las medidas más importantes para eliminar y prevenir las infestaciones causadas por roedores.

  9. Las ideologias, las ciencias naturales y sus implicaciones en la educacion cientifica

    NASA Astrophysics Data System (ADS)

    Lozada Roldan, Sandra

    Este estudio ausculto las concepciones epistemologicas de los docentes de ciencia del nivel secundario con relacion a las ideologias y las ciencias naturales. Tambien examino las posiciones de los docentes ante asuntos publicos relacionados a la ciencia. Para propositos de este estudio se diseno y se valido el cuestionario con el cual se obtuvieron los resultados. La investigacion es de tipo cuantitativa y se utilizo como diseno la encuesta. El cuestionario se administro en varias actividades de desarrollo profesional para maestros de ciencia. Un total de 78 maestros del nivel secundario respondieron el cuestionario. Para analizar los datos obtenidos se utilizaron estadisticas descriptivas como la distribucion de frecuencia y el porciento. Ademas se establecieron codigos y categorias para describir las posiciones de los maestros ante asuntos publicos relacionados a la ciencia. Los analisis demostraron que entre los docentes participantes de este estudio prevalecen ciertas concepciones epistemologicas adecuadas acerca de las ciencias naturales, a la luz de la literatura consultada. Entre estas concepciones se destacan las siguientes: a) la filosofia materialista de las ciencias naturales, b) la naturaleza tentativa y constructivista del conocimiento cientifico, c) el uso de una metodologia que garantiza cierto grado de objetividad y con el que se justifican y validan los enunciados cientificos y d) la funcion instrumental del conocimiento cientifico. Sin embargo, entre los docentes participantes de este estudio prevalecen ciertas concepciones epistemologicas erroneas acerca de las ciencias naturales, a la luz de la literatura consultada. Entre estas concepciones se destacan las siguientes: a) tendencia inductivista en el que las teorias cientificas comienzan con observaciones que establecen generalizaciones, b) secuencia jerarquica de la metodologia cientifica. Ademas, entre los docentes participantes de este estudio prevalecen concepciones epistemologicas adecuadas

  10. Overview of the land analysis system (LAS)

    USGS Publications Warehouse

    Quirk, Bruce K.; Olseson, Lyndon R.

    1987-01-01

    The Land Analysis System (LAS) is a fully integrated digital analysis system designed to support remote sensing, image processing, and geographic information systems research. LAS is being developed through a cooperative effort between the National Aeronautics and Space Administration Goddard Space Flight Center and the U. S. Geological Survey Earth Resources Observation Systems (EROS) Data Center. LAS has over 275 analysis modules capable to performing input and output, radiometric correction, geometric registration, signal processing, logical operations, data transformation, classification, spatial analysis, nominal filtering, conversion between raster and vector data types, and display manipulation of image and ancillary data. LAS is currently implant using the Transportable Applications Executive (TAE). While TAE was designed primarily to be transportable, it still provides the necessary components for a standard user interface, terminal handling, input and output services, display management, and intersystem communications. With TAE the analyst uses the same interface to the processing modules regardless of the host computer or operating system. LAS was originally implemented at EROS on a Digital Equipment Corporation computer system under the Virtual Memorial System operating system with DeAnza displays and is presently being converted to run on a Gould Power Node and Sun workstation under the Berkeley System Distribution UNIX operating system.

  11. EPA orders City of North Las Vegas to safeguard Las Vegas Wash from potential water pollution

    EPA Pesticide Factsheets

    SAN FRANCISCO - The U.S. Environmental Protection Agency issued an order to the City of North Las Vegas to take immediate steps to address federal Clean Water Act violations. Deficiencies in the management of its wastewater pretreatment program have

  12. LANDSCAPE CHANGE OF THE LAS VEGAS VALLEY, 1972 TO 1998

    EPA Science Inventory

    Las Vegas has become one of the fastest growing metropolitan areas in the United States. The cities population has doubled from 1980 to 1994 and in 1995 Las Vegas has surpassed the one million mark. The population of Las Vegas is currently growing at a rate of 7 percent annually....

  13. ?Cuales son las amenazas o peligros volcanicos?

    USGS Publications Warehouse

    Myers, Bobbie; Brantley, Steven R.; Stauffer, Peter; Hendley, James W.

    2000-01-01

    Los volcanes son capaces de producir numerosos peligros geologicos e hidrologicos. Los cientificos del Servicio Geologico de los EE. UU. (USGS, por sus siglas en ingles) y de otras instituciones alrededor del mundo estan estudiando los peligros de muchos de los centenares de volcanes activos y potencialmente activos del mundo. Estos cientificos vigilan muy de cerca la actividad de algunos de los volcanes mas peligrosos, por lo que estan preparados para alertar a las autoridades y/o a la poblacion en caso de que aumente sustancialmente la probabilidad de que ocurra una erupcion u otro evento peligroso.

  14. Resource Conservation and a Sustainable Las Vegas

    SciTech Connect

    Piechota, Thomas C.

    2014-05-15

    This research project developed educational, research, and outreach activities that addressed the challenges of Las Vegas as related to a secure energy supply through conservation, clean and adequate water supply, economic growth and diversification, air quality, and the best use of land, and usable public places. This was part of the UNLV Urban Sustainability Initiative (USI) that responded to a community and state need where a unifying vision of sustainability was developed in a cost-effective manner that promoted formal working partnerships between government, community groups, and industry.

  15. Relevamiento de HI en las Nubes de Magallanes

    NASA Astrophysics Data System (ADS)

    Bajaja, E.; Morras, R.; Arnal, E. M.; Pöppel, W. G. L.

    El relevamiento de HI en el hemisferio sur, que se está realizando desde el IAR con el nuevo receptor enfriado, abarca, en su rango de velocidades, las velocidades desplegadas por el hidrógeno neutro de las Nubes de Magallanes. Esto permite obtener los perfiles de velocidad correspondientes a estas galaxias con una sensibilidad y una completitud de grilla excepcionales para el estudio de la distribución y de la cinemática del gas a gran escala y con una resolución angular de 30' y una resolución en velocidad de 1 km/s. Estas condiciones permiten el estudio de los campos de velocidad, de las componentes múltiples en velocidad, de las asimetrías, concentraciones y burbujas en la distribución del gas, los puentes entre las Nubes y entre las Nubes y la Galaxia, etc. Estas características son de particular importancia para su correlación con los mapas obtenidos con las emisiones en el radio-continuo, el IR y el CO (relacionable con el hidrógeno molecular) todas las cuales permiten el estudio de la dinámica de las Nubes y su relación con la Galaxia, de la formación y evolución estelar y de la evolución de la Nubes mismas.

  16. Variación temporal de las constantes fundamentales

    NASA Astrophysics Data System (ADS)

    Landau, S. J.; Vucetich, H.

    La variación temporal de las constantes fundamentales es un problema que ha motivado numerosos trabajos teóricos y experimentales desde la hipótesis de los grandes números de Dirac en 1937. Entre los métodos experimentales y observacionales para establecer restricciones sobre la variación de las constantes fundamentes es importante mencionar: comparación entre relojes atómicos[1], métodos geofísicos[2][3], análisis de sistemas de absorción en quasares[4][5][6] y cotas provenientes de la nucleosíntesis primordial[7]. En un trabajo reciente[5], se reportó una significativa variación en la constante de estructura fina. Intentos de unificar las cuatro interacciones fundamentales dieron como resultado teorías con múltiples dimensiones como las teorías de Kaluza-Klein y teorías de supercuerdas. Estas teorías proporcionan un marco teórico natural para el estudio de la variación temporal de las constantes fundamentales. A su vez, un modelo sencillo para estudiar la variación de la constante de estructura fina, fue propuesto en [8], a partir de premisas muy generales como ser covarianza, invarianza de gauge, causalidad y invarianza ante reversiones temporales en el electromagnetismo. Diferentes versiones de las teorías antes mencionadas coinciden en predecir variaciones temporales de las constantes fundamentales pero difieren en la forma de esta variación[9][10]. De esta manera, las restricciones establecidas experimentalmente sobre la variación de las constantes fundamentales pueden ser una herramienta importante para testear estas diferentes teorías. En este trabajo, utilizamos las cotas provenientes de diversas técnicas experimentales, para testear si las mismas son consistentes con alguna de las teorías antes mencionadas. En particular, establecemos cotas sobre la variación de los parámentros libres de las diferentes teorías como por ejemplo el radio de las dimensiones extras en las teorías tipo Kaluza-Klein.

  17. The Las Campanas Infrared Survey Camera

    NASA Astrophysics Data System (ADS)

    Persson, S. E.; Murphy, D. C.; Gunnels, S. M.; Birk, C.; Bagish, A.; Koch, E.

    2002-07-01

    The Las Campanas Infrared Survey Camera is a near-infrared (1.0-2.5 μm), wide-area instrument used to detect and measure the photometric properties of galaxies out to large redshifts, z>2. The camera, a modified Offner 1:1 reimaging optical system, is mounted at the f/7.5 focus of the 2.5 m du Pont Telescope. The detectors are four Rockwell 1024×1024 HgCdTe (HAWAII) arrays operating at a scale of 0.20" pixel-1. With four telescope pointings, the instrument produces a pipelined mosaic of J, H, or Ks images 13'×13' on the sky, with a measured point-spread function as good as 0.38" FWHM. The good imaging quality results in part from fast tip-tilt guiding on stars within a 9'×9' field centered on the optical axis of the telescope. Appropriately bright guide stars are found within 2 s from a catalog of 5×107 stars and presented as a ``finding chart'' to the observer. The optical, mechanical, and thermal design choices and their associated engineering implementations are discussed in some detail. The detector readout electronics, the automatic data acquisition and control system, and our data reduction pipeline are also described. The design goals of the camera-excellent imaging quality and throughput, low flexure and internal background, and 5 Hz on-axis guiding, are all realized and quantified.

  18. La variación temporal de las constantes fundamentales

    NASA Astrophysics Data System (ADS)

    Bersten, M.; Landau, S.; Vucetich, H.

    Las diferentes teorías que unifican las cuatro interacciones fundamentales coinciden en predecir variaciones temporales y espaciales de las constantes fundamentales pero difieren en la forma de esta variación. Las observaciones astronómicas y geofísicas permiten establecer cotas sobre la variación de dichas constantes. ésto nos proporciona una herramienta importante para testear las diferentes teorías. En particular, se utilizó el modelo de supercuerdas propuesto por Damour y Polyakov. Se obtuvieron límites sobre los parámetros libres de dicho modelo consistentes con un conjunto de datos astronómicos y geofísicos.

  19. LAS - LAND ANALYSIS SYSTEM, VERSION 5.0

    NASA Technical Reports Server (NTRS)

    Pease, P. B.

    1994-01-01

    The Land Analysis System (LAS) is an image analysis system designed to manipulate and analyze digital data in raster format and provide the user with a wide spectrum of functions and statistical tools for analysis. LAS offers these features under VMS with optional image display capabilities for IVAS and other display devices as well as the X-Windows environment. LAS provides a flexible framework for algorithm development as well as for the processing and analysis of image data. Users may choose between mouse-driven commands or the traditional command line input mode. LAS functions include supervised and unsupervised image classification, film product generation, geometric registration, image repair, radiometric correction and image statistical analysis. Data files accepted by LAS include formats such as Multi-Spectral Scanner (MSS), Thematic Mapper (TM) and Advanced Very High Resolution Radiometer (AVHRR). The enhanced geometric registration package now includes both image to image and map to map transformations. The over 200 LAS functions fall into image processing scenario categories which include: arithmetic and logical functions, data transformations, fourier transforms, geometric registration, hard copy output, image restoration, intensity transformation, multispectral and statistical analysis, file transfer, tape profiling and file management among others. Internal improvements to the LAS code have eliminated the VAX VMS dependencies and improved overall system performance. The maximum LAS image size has been increased to 20,000 lines by 20,000 samples with a maximum of 256 bands per image. The catalog management system used in earlier versions of LAS has been replaced by a more streamlined and maintenance-free method of file management. This system is not dependent on VAX/VMS and relies on file naming conventions alone to allow the use of identical LAS file names on different operating systems. While the LAS code has been improved, the original capabilities

  20. La edad de las familias Eos, Themis y Koronis

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.

    Las familias de asteroides son el producto de la disrupción colisional de objetos destruídos por impactos ocurridos en el cinturón principal. Las colisiones posteriores han modificado los tamaños y las órbitas de los miembros de estas familias, por lo que las distribuciones que vemos hoy en día pueden ser muy diferentes de aquellas producidas inmediatamente después de la fragmentación del objeto original. En esta hipótesis, puede ser difícil reconstruir la evolución colisional de la familia basándose sólo en las actuales distribuciones y puede ser necesario hacer ciertas suposiciones para obtener información sobre las condiciones iniciales. En este trabajo se deriva una estimación de la edad de las familias Eos, Themis y Koronis obtenida de una simulación de la evolución colisional de un cuerpo original teórico para cada familia usando un modelo de distribución para el cinturón propuesto por Gil-Hutton (1996).

  1. Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants.

    PubMed

    Temmink, H; Klapwijk, Bram

    2004-02-01

    Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C12-homologue of linear alkyl benzene sulfonate (LAS-C12). The pilot-plant was operated at influent LAS-C12 concentrations between 2 and 12 mg l(-1) and at sludge retention times of 10 and 27 days. Effluent and waste sludge concentrations varied between 5 and 10 microg l(-1) and between 37 and 69 microg g(-1) VSS, respectively. In the sludge samples only 2-8% was present as dissolved LAS-C12, whereas the remaining 92-98% was found to be adsorbed to the sludge. In spite of this high degree of sorption, more than 99% of the LAS-C12 load was removed by biodegradation, showing that not only the soluble fraction but also the adsorbed fraction of LAS-C12 is readily available for biodegradation. Sorption and biodegradation of LAS-C12 were also investigated separately. Sorption was an extremely fast and reversible process and could be described by a linear isotherm with a partition coefficient of 3.2 l g(-1) volatile suspended solids. From the results of biodegradation kinetic tests it was concluded that primary biodegradation of LAS-C12 cannot be described by a (growth) Monod model, but a secondary utilisation model should be used instead. The apparent affinity of the sludge to biodegrade LAS-C12 increased when the sludge was loaded with higher influent concentrations of LAS-C12.

  2. Safety of the Las Vegas left-turn display.

    PubMed

    Ozmen, Ozlem; Tian, Zong Z; Gibby, A Reed

    2014-01-01

    This paper provides a safety evaluation of a special protected/permitted left turn signal control (Las Vegas LT Display) that has been implemented in the urbanized area of Las Vegas, Nevada. The Las Vegas LT Display eliminates the yellow trap condition for leading approach in lead/lag operation. It provides protected only left turns during certain times of day by suppressing the permitted green ball and yellow ball displays. Before and after studies were conducted using the crash data from 10 intersections. Results from the analyses indicated that no obvious safety concerns due to use of the special display.

  3. The Land Analysis System (LAS) for multispectral image processing

    USGS Publications Warehouse

    Wharton, S. W.; Lu, Y. C.; Quirk, Bruce K.; Oleson, Lyndon R.; Newcomer, J. A.; Irani, Frederick M.

    1988-01-01

    The Land Analysis System (LAS) is an interactive software system available in the public domain for the analysis, display, and management of multispectral and other digital image data. LAS provides over 240 applications functions and utilities, a flexible user interface, complete online and hard-copy documentation, extensive image-data file management, reformatting, conversion utilities, and high-level device independent access to image display hardware. The authors summarize the capabilities of the current release of LAS (version 4.0) and discuss plans for future development. Particular emphasis is given to the issue of system portability and the importance of removing and/or isolating hardware and software dependencies.

  4. RadNet Air Data From Las Vegas, NV

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Las Vegas, NV from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  5. An overview of the Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Lu, Yun-Chi

    1986-01-01

    An outline covering the history, development methodology, and major hardware/software components of the Land Analysis System (LAS) is presented. System support services including the Transportable Applications Executive (TAE), Catalog Manager, history files, and applications services are briefly described along with the general functional capabilities of the 224 available applications programs. Example interface menus are given and desired enhancements to the LAS system are listed.

  6. Actitudes de los candidatos y maestros de ciencias en servicio acerca del uso de las herramientas computadorizadas en las clases de ciencias

    NASA Astrophysics Data System (ADS)

    Bayuelo, Ezequiel

    Este estudio examino y comparo las actitudes de los candidatos a maestros de ciencias y los maestros de ciencias en servicio acerca de la utilizacion de las herramientas computadorizadas en las clases de ciencias. Tambien identifico y diferencio el uso que ellos dan a estas herramientas en las clases de ciencias. Este estudio presenta un diseno descriptivo exploratorio. Constituyeron la muestra trescientos diez sujetos que fueron candidatos a maestros de ciencias o maestros de ciencias en servicio. Para recoger los datos se construyo y valido un cuestionario de treinta y un itemes. Se utilizaron las pruebas estadisticas no parametricas Kruskal Wallis y Chi-cuadrado (test de homogeneidad) para establecer las diferencias entre las actitudes de los sujetos con relacion al uso de las herramientas computadorizadas en las clases de ciencias. Los hallazgos evidenciaron que son positivas y muy parecidas las actitudes de los candidatos a maestros y maestros en servicio hacia el uso de las herramientas computadorizadas. No hubo diferencias entre los candidatos y maestros en servicio en terminos de las actitudes de confianza y empatia hacia el uso de las herramientas computadorizadas en las clases de ciencias. En aspectos como el uso del banco de datos bibliografico Eric y el uso de las herramientas computadorizadas en actividades educativas como explorar conceptos, conceptuar, aplicar lo aprendido y hacer asignaciones hubo diferencias estadisticamente significativas entre los candidatos y los maestros en servicio. Al comparar las frecuencias observadas con las esperadas hubo mas maestros en servicio y menos candidatos que indicaron usar el anterior banco de datos y las herramientas computadorizadas en las mencionadas actividades educativas.

  7. Las dificultades de sentir: el rol de las emociones en la estigmatización del VIH/SIDA

    PubMed Central

    MARZÁN-RODRÍGUEZ, Melissa; VARAS-DÍAZ, Nelson

    2009-01-01

    Resumen El Virus de Inmunodeficiencia Humana (VIH) y el Síndrome de Inmunodeficiencia Adquirida (SIDA) han sido motivo de estigmatización para las personas que viven con ellos. Esta estigmatización se ha estudiado consecuentemente desde la perspectiva de opiniones de agentes estigmatizantes. Estas opiniones han obviado sistemáticamente el rol de las emociones en el proceso de estigmatización. Llevamos a cabo este estudio con el propósito de identificar el rol de las emociones en el proceso de estigmatización de las personas que viven con el virus (PVVS) por parte de profesionales de la salud. Para lograr este objetivo utilizamos un diseño exploratorio y cualitativo en el cual utilizamos la técnica de entrevistas semiestructuradas a profundidad. La muestra estuvo compuesta por 80 profesionales de la salud y estudiantes de las siguientes especialidades: psicología, trabajo social, medicina y enfermería. Los resultados reflejaron la existencia de emociones asociadas al VIH/SIDA tales como pena, lástima, compasión, asco, fobia y miedo entre los/as profesionales y estudiantes que participaron. Las personas participantes evidenciaron la necesidad de controlar sus emociones al interactuar con PVVS. Los resultados apuntan a la necesidad de explorar aquellos factores que mediatizan las emociones, tales como el contexto social en que se manifiestan y ante quiénes se revelan, para lograr entender a cabalidad el estigma que rodea al VIH/SIDA. PMID:20212916

  8. 77 FR 1720 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting..., the U.S. Department of the Interior, Bureau of Land Management (BLM), Las Cruces District Resource... BLM Las Cruces District Office, 1800 Marquess Street, Las Cruces, NM 88005, from 10 a.m.-4 p.m....

  9. 77 FR 18858 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting..., the U.S. Department of the Interior, Bureau of Land Management (BLM), Las Cruces District Resource... Las Cruces District Office, 1800 Marquess Street, Las Cruces, NM 88005, from 10 a.m.-4 p.m. The...

  10. LAS: a software platform to support oncological data management.

    PubMed

    Baralis, Elena; Bertotti, Andrea; Fiori, Alessandro; Grand, Alberto

    2012-11-01

    The rapid technological evolution in the biomedical and molecular oncology fields is providing research laboratories with huge amounts of complex and heterogeneous data. Automated systems are needed to manage and analyze this knowledge, allowing the discovery of new information related to tumors and the improvement of medical treatments. This paper presents the Laboratory Assistant Suite (LAS), a software platform with a modular architecture designed to assist researchers throughout diverse laboratory activities. The LAS supports the management and the integration of heterogeneous biomedical data, and provides graphical tools to build complex analyses on integrated data. Furthermore, the LAS interfaces are designed to ease data collection and management even in hostile environments (e.g., in sterile conditions), so as to improve data quality.

  11. Navajo minettes in the Cerros de las Mujeres, New Mexico

    NASA Astrophysics Data System (ADS)

    Vaniman, D.; Laughlin, A. W.; Gladney, E. S.

    1985-06-01

    The Cerros de las Mujeres in west-central New Mexico are three mafic minette plugs that should be considered part of the Navajo volcanic fields on the central Colorado Plateau. This newly recognized occurrence extends the Navajo volcanic fields to the southeastern margin of the Colorado Plateau, within 45 km of the extensional tectonic setting in which the Mogollon ash-flow tuff cauldrons occur. The Cerros de las Mujeres provide additional evidence for contemporaneous sodic and potassic volcanism within the Navajo volcanic fields.

  12. The Las Vegas Sustainability Atlas: Modeling Place-based Interactions and Implications in the Las Vegas Valley Bioregion

    NASA Astrophysics Data System (ADS)

    Ego, H.; McCown, K.; Saghafi, N.; Gross, E.; Hunter, W.; Zawarus, P.; Gann, A.; Piechota, T. C.

    2014-12-01

    Las Vegas, Nevada, with 2 million residents and 40 million annual visitors, is one of the driest metropolitan environments of its size in the world. The metro imports nearly all of its resources, including energy, water and food. Rapid population increases, drought, and temperature increases due to climate change create challenges for planning resilient systems in the Las Vegas Valley. Because of its growth rate, aridity, Las Vegas, Nevada is a significant and relevant region for the study of the water, energy, food and climate nexus. Cities in the United States and the world are seeing increasing trends in urbanization and water scarcity. How does the water-energy-climate-food nexus affect each metropolitan area? How can this complex information be used for resiliency planning? How can it be related to the public, so they can understand the issues in a way that makes them meaningful participants in the planning process? The topic of our presentation is a 'resiliency atlas.' The atlas is a place-based model tested in Las Vegas to explore bioregional distinctiveness of the water-energy-climate-food nexus, including regional transportation systems. The atlas integrates the systems within a utilitarian organization of information. Systems in this place-based model demonstrate how infrastructure services are efficiently provided for the Las Vegas Valley population. This resiliency atlas can clarify how the nexus applies to place; and how it can be used to spur geographically germane adaption strategies. In the Las Vegas Valley, climate change (drought and high sustained temperatures) and population affect water, energy, and food systems. This clarity of a place based model can help educate the public about the resilience of their place, and facilitate and organize the planning process in the face of uncertainty.

  13. Solar Hot Water for a Motor Inn -- Las Vegas, Nevada

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Solar hot-water installation at motor inn in Las Vegas, Nevada is described in report containing descriptions of design, philosophy, operation of system and problems and solutions. Provides drawings of solar roof plan, operator's instructions, manufacturers' brochures and copy of acceptance report.

  14. Las Rocas Nos Cuentan (Rocks Tell Their Stories)

    ERIC Educational Resources Information Center

    Llerandi-Roman, Pablo A.

    2012-01-01

    Many Earth science lessons today still focus on memorizing the names of rocks and minerals. This led the author to develop a lesson that reveals the fascinating stories told by rocks through the study of their physical properties. He first designed the lesson for Puerto Rican teachers, hence its Spanish title: "Las Rocas Nos Cuentan Su Historia."…

  15. Experiencing Architecture: The Young People's Library Department in Las Vegas.

    ERIC Educational Resources Information Center

    Dixon, Joyce K.

    1991-01-01

    Describes the development of the Young People's Library in Las Vegas (Nevada) as a symbolic and literal bridge to the Lied Discovery Children's Museum. The roles in the design process of library administration, library personnel, and the architect are explored, and how this project addressed differences between the architect's artistic vision and…

  16. Reading "Las Meninas": An Ekphrastic Approach to Teaching "Don Quijote"

    ERIC Educational Resources Information Center

    Ortuno, Marian

    2012-01-01

    Reading and teaching "Don Quijote" present multiple challenges to twenty-first century students and instructors who are culturally and historically distanced from the seventeenth century. With "Las Meninas" serving as a visual lexicon for cuing correlative themes and events in "Don Quijote", the instructor, through an ekphrastic, interdisciplinary…

  17. EPA Sparks Local Business in Las Cruces, N.M.

    EPA Pesticide Factsheets

    DALLAS - (Feb. 29, 2016) The U.S. Environmental Protection Agency (EPA) is awarding a $300,000 small business contract to Vista Photonics, Inc. in Las Cruces, N.M. The company plans to develop an inexpensive, high-performance, portable air pollution

  18. Thermal expansion in metal/lithia-alumina-silica (LAS) composites

    NASA Astrophysics Data System (ADS)

    Wolff, E. G.

    1988-03-01

    Lithia-alumina-silica (LAS) with metallic dispersions offers a new approach toward near-zero, isotropic, thermal expansion composites. The metallic phase contributes a positive coefficient of thermal expansion (CTE) to the negative CTE of the glass/ceramic matrix. In addition, the metal will increase the electrical and thermal conductivities over those of the matrix alone. The LAS system offers tailorable negative CTEs and light weight compared to other negative CTE ceramics. The most negative CTE phase is crystalline β-eucryptite, whose proportion in an initially glassy matrix can be controlled by heat treatment. Dispersed metal powders were both hot-pressed and cold-pressed and sintered together with LAS matrices prepared by sol gel methods. Super Invar powder was studied for its minimal CTE mismatch, while titanium powders offered a compromise between light weight and low CTE. An ultralow-expansion (ULE) glass- and linear variable differential transducer (LVDT)-based differential dilatometer was developed for rapid screening of compositions, while a double-laser Michelson interferometer was used for precise near-zero CTE measurements. The reinforced β-eucryptite glass/ceramic matrix exhibited both a U-shaped ΔL/L curve with temperature and some thermal hysteresis, depending on the fabrication and heat treatment sequences. The temperature of the zero-CTE portion of this curve was found to change with increasing titanium powder content. Results are also given for mixtures of Super Invar powders in ULE glass and β-eucryptite matrices. Negative CTEs in a LAS matrix above ambient temperatures were more difficult to obtain than below, although the use of petalite (high-silica LAS) appears promising.

  19. [Biodegradation of LAS in the anaerobic water of a representative inlet of Lake Dianchi].

    PubMed

    Wang, Zhi; Tu, Xin-hai; Xiao, Bang-ding; Wu, Xing-qiang; Liu, Min; Chen, Xu-dong

    2008-08-01

    Biodegradation and degradation kinetics of anion-surfactant (LAS) in the anaerobic water of a representative inlet (Haihe River) of Lake Dianchi under different incubation conditions were studied by the 'river die-away' test method. The influences of temperature, pH, initial concentration of LAS, aeration condition and added nutrients (NH4Cl or NaH2PO4) on the biodegradation of LAS in the water were investigated. The results demonstrate that LAS can be biodegraded by microorganisms in the water and that the percentage of degradation of LAS was more than 95% after 26 d. The biodegradation of LAS fit the second kinetic model. Incubation temperature, initial concentration of LAS, aeration and added nutrients (NH4Cl or NaH2PO4) can all affect the biodegradation of LAS. When the incubation temperature increased from 10 degrees C to 25 degrees C, the biodegradation rate (p) of LAS increased from 0.21 d(-1) to 0.90 d(-1). The LAS degradation rate increased from 0.72 d(-1) under anaerobic condition to 1.97 d(-1) under continuous aeration condition. The increased initial concentrations of LAS lead to decrease of the biodegradation rate. NaH2PO4 accelerated the degradation of LAS but added NH4Cl instead inhibited degradation. In our experiment, pH value (7.05-9.44) had little influence on the biodegradation of LAS.

  20. Solar hot water system installed at Las Vegas, Nevada

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A solar energy hot water system installed in a motor inn at Las Vegas, Nevada is described. The inn is a three story building with a flat roof for installation of the solar panels. The system consists of 1,200 square feet of liquid flat plate collectors, a 2,500 gallon insulated vertical steel storage tank, two heat exchangers, and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

  1. Ecological protection in the Las Tres Virgenes, Mexico, geothermal field

    SciTech Connect

    Zirahuen Ortega Varela, J.R.

    1996-12-31

    The programs of environmental protection designed by Comision Federal de Electricidad are described in a general way. These programs detect, avoid, soften and compensate the environmental impacts product of the exploration, construction and operation activities of the geothermal field Las Tres Virgenes, this field is in the buffer zone of the biosphere reserve {open_quotes}El Vizcaino{close_quotes} at the north of the State of Baja California Sur, Mexico.

  2. Geology of Las Vegas, Nevada, United States of America

    SciTech Connect

    Wyman, R.V.; Karakouzian, M. ); Bax-Valentine, V. ); Peterson, L.; Palmer, S. ); Slemmons, D.B.

    1993-03-01

    Las Vegas is one of the fastest growing cities in the US. Its regional geologic setting is in the Basin and Range geomorphic province and in the Sevier orogenic belt. The city itself lies in a broad north-south valley formed by coalescing alluvial fans and lake beds which give rise to several soil and foundation problems. Although destructive earthquakes have not occurred in the Las Vegas area in modern times, the record is very short. Major earthquakes could have taken place in the past when the area was unoccupied except for a few nomadic tribes. Studies are underway to better define the seismicity. Although the climate is hot and dry, flash flooding occurs frequently from late summer thunderstorms and torrential rains. The Regional Flood Control District is actively constructing retention basins and drainage improvements for diversion and protection from such floods. Water supply is a problem for the increasing population. The groundwater supply has long been overdrawn, and the allotment to Nevada under the Colorado River Compact will be completely utilized in the near future. Las Vegas has faced the problems of solid waste disposal, water treatment, rational water use, flooding and earthquakes - all of which are related to the unique geologic and geomorphic setting.

  3. GIS methodology for quantifying channel change in Las Vegas, Nevada

    USGS Publications Warehouse

    Buckingham, S.E.; Whitney, J.W.

    2007-01-01

    This study applies spatial analyses to examine the consequences of accelerated urban expansion on a hydrologic system over a period of 24 years. Three sets of historical aerial photos are used in a GIS analysis to document the geomorphic history of Las Vegas Wash, which drains the rapidly growing Las Vegas urban area in southern Nevada. New spatial techniques are introduced to make quantitative measurements of the erosion at three specific time intervals in the hydrologic evolution of the channel and floodplain. Unlike other erosion studies that use two different elevation surfaces to assess erosion, this study used a single elevation surface to remove systematic and nonsystemic elevation errors. The spatial analysis quantifies channel changes for discrete time periods, calculates erosion volumes, and provides a foundation to examine how the specific mechanisms related to urban expansion have affected Las Vegas Wash. The erosion calculated over 24 years is the largest documented sediment loss attributed to the effect of rapid urban growth. ?? 2007 American Water Resources Association.

  4. Port Risk Assessment Port of Ponce, Guayanilla, Yabucoa, and Las Mareas, Puerto Rico, After Action Report

    DTIC Science & Technology

    2000-02-10

    Port Assessment Ponce, Guayanilla, Yabucoa, and Las Mareas Port of Ponce, Guayanilla, Yabucoa, and Las Mareas , Puerto Rico, After Action Report...Introduction. A Port Risk Assessment was conducted for the port of Ponce, Guayanilla, Yabucoa, and Las Mareas , Puerto Rico (South Central...3. DATES COVERED 00-00-2000 to 00-00-2000 4. TITLE AND SUBTITLE Port Risk Assessment Port of Ponce, Guayanilla, Yabucoa, and Las Mareas

  5. Source Water Assessment for the Las Vegas Valley Surface Waters

    NASA Astrophysics Data System (ADS)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality

  6. 77 FR 77090 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated..., 4100 Dripping Springs Road, Las Cruces, NM, 88005 from 9 a.m.-4 p.m. The public may send...

  7. 78 FR 20354 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on April 23, 2013, at the BLM Las Cruces District Office Main...

  8. 78 FR 44590 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on August 22, 2013, at the BLM Las Cruces District Office...

  9. 78 FR 65356 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on November 20, 2013, at the BLM Las Cruces District Office...

  10. 76 FR 35371 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of the Las Vegas, NV, Class B... information from airspace users and others, concerning a proposal to modify Class B airspace at Las Vegas, NV... Centennial Parkway, Las Vegas, NV 89149; (2) The meeting on Tuesday, August 23, 2011, will be held...

  11. La importancia de la protección de las playas

    EPA Pesticide Factsheets

    Las playas son una parte importante de la vida en Estados Unidos. Las playas ofrecen un sinnúmero de beneficios para el medio ambiente, actividades recreativas y la economía local. Aprenda la importancia de las playas y cómo protegerlas.

  12. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Las Vegas Intrastate Air...

  13. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Las Vegas Intrastate Air...

  14. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Las Vegas Intrastate Air...

  15. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Las Vegas Intrastate Air...

  16. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Las Vegas Intrastate Air...

  17. Geological Mapping Using Legacy Geophysical Data in Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Donovan, D.; O'Donnell, J.; McLin, K.

    2014-12-01

    In 2008-2011, Clark County, Building Department contracted with Optim to collect 10,700 Reflection Microtremor (ReMi) 600 ft seismic lines that cover most of the metropolitan area of Las Vegas and other outlying communities such as Moapa, Laughlin, Primm, and Coyote Spring. The County completed their goal of characterizing seismic susceptibility of the top 100 ft and the results are posted at http://gisgate.co.clark.nv.us/openweb/. The research question of the authors is: What additional geologic information can be inferred from the data, either through reprocessing, cross correlation of drill hole data or additional data collection? An advantage of geophysical data is that it can be reprocessed to provide additional insight into the local geologic setting. The interpretation is also improved if combined with drill hole data and / or hydrologic information. It should be noted that there is also legacy geophysical data in limited areas collected by the USGS, primarily in conjunction with water well drilling, where some of the ReMi seismic data was collected. An unexpected result of the ReMi survey was a clear delineation of current and paleo channels in Laughlin, Moapa, and Las Vegas. The geometry of the paleochanel, of the Colorado River, is well away from the current position. however the signal is very similar to modern streams such as the Muddy River. Although the surficial geologic mapping in Las Vegas Valley was very detailed, and importantly, was performed prior to development; the new geophysical data provides better details of the lithologic properties of the units. That is it may be an excellent basis for remapping for specific properties related to engineering and hydrologic modeling.

  18. Linear alkyl benzene sulphonate (LAS) degradation by immobilized Pseudomonas aeruginosa under low intensity ultrasound.

    PubMed

    Lijun, Xiang; Bochu, Wang; Zhimin, Li; Chuanren, Duan; Qinghong, Wang; Liu, Liu

    2005-01-15

    We studied the LAS degradation of immobilized Pseudomonas aeruginosa with low-intensity ultrasonic and the influence of original LAS concentration, pH, rotary velocity and different conditions of low-intensity ultrasonic irradiation on the degradation of LAS. In our experiment, the degradation rate of LAS was the main index. We found that low-intensity ultrasonic irradiation could improve the metabolism of microorganism cells and promote the LAS biodegradation of immobilized cells. In the experiment, 50 mg/l LAS were used to simulate wastewater, and low-intensity ultrasonic was considered. We found the influence was obvious, and the optimal degradation rate was acquired when the conditions of ultrasonic were frequency 24 kHz, power 8 W, stimulation time 5 s, intermissive time 30 s, and total time 10 min. The LAS degradation rate of immobilized cells with ultrasonic were respectively 40% and 9.5% higher than that of the suspending cells and immobilized cells without irradiation.

  19. El libro del Relogio del Palacio de las Horas

    NASA Astrophysics Data System (ADS)

    Morales, J. D.

    2009-08-01

    This paper resume the investigation entitled ``El libro del Relogio del Palacio de las Horas''. That consist in an edition of the original text of the book of the Clock of the Palace of the Hours from the Books of the knowledge of Astronomy of Alfonso X (Manuscript 156, Complutense University). And a description of the astronomical functionality of the Clock of the Palace of the Hours. It includes a geometric description of the positional astronomy on which the operation of the Palace is based.

  20. Revision curricular a partir de un analisis comparativo de las discrepancias en los curriculos de una escuela de optometria en Puerto Rico con las competencias requeridas para las agencias de revalida y acreditacion 2004

    NASA Astrophysics Data System (ADS)

    Rivera Pacheco, Andres

    El proposito de esta investigacion, un estudio cualitativo de caso, fue comparar y contrastar el curriculo vigente de la Escuela de Optometria de la UIAPR con las competencias y estandares requeridos por las agencias de acreditacion y de revalida. Con este proposito, decidimos realizar una revision y un analisis de documentos: el prontuario de cada uno de los cursos de los curriculos implantados en el 1993 y en el 2001; las competencias y estandares establecidos por las agencias de revalida y de acreditacion; y las estadisticas en las que se analiza el porcentaje de estudiantes que aprueban cada una de las partes de los examenes de revalida entre el 1998 al 2003. Se realizaron entrevistas dirigidas para dar apoyo y complementar la revision y el analisis de estos documentos. Los participantes de las entrevistas fueron tres estudiantes de la clase de optometria del 2004 (ultima clase del curriculo del 1993); tres estudiantes de la clase de optometria del 2005 (primera clase graduanda del curriculo vigente) y tres profesores y/o directores de los Departamentos de Ciencias Basicas, Ciencias Clinicas y Cuidado al Paciente. Esta investigacion se enmarco en el modelo de evaluacion curricular de discrepancia de Malcolm Provus y en el modelo de desarrollo basado en competencias. Uno de los hallazgos mas importantes del estudio es que los cambios que se implantaron al curriculo del 2001 no han logrado que los estudiantes mejoren su ejecucion en los examenes de revalida. Por otro lado, se encontro que el curriculo vigente atiende completamente los estandares de la practica de Optometria, pero no las competencias. Esta informacion fue validada mediante el uso de una tabla de cotejo para el analisis de los cursos y de la informacion obtenida de las entrevistas. El estudio determina y concluye que existen discrepancias entre los prontuarios de los cursos del curriculo y las competencias requeridas por la agencia de revalida. Segundo, que el Departamento de Ciencias Basicas es el

  1. Effects of process stability on anaerobic biodegradation of LAS in UASB reactors.

    PubMed

    Løbner, Trine; Toräng, Lars; Batstone, Damien John; Schmidt, Jens Ejbye; Angelidaki, Irini

    2005-03-30

    Anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) was studied in upflow anaerobic sludge blanket (UASB) reactors operated under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. LAS C12 concentration in the influents was 10 mg.L(-1), and the hydraulic retention time in the reactors was 2 days. Adsorption of LAS C12 was assessed in an autoclaved control reactor and ceased after 115 days. The reactors were operated for a minimum of 267 days; 40-80% removal of LAS C12 was observed. A temperature reduction from 55 degrees C to 32 degrees C for 30 h resulted in process imbalance as indicated by increase of volatile fatty acids (VFA). The imbalance was much more intense in the LAS amended reactor compared with an unamended reactor. At the same time, the process imbalance resulted in discontinued LAS removal. This finding indicates that process stability is a key factor in anaerobic biological removal of LAS. After a recovery period, the removal of LAS resumed, providing evidence of biological anaerobic LAS degradation. The removal remained constant until termination of experiments in the reactor. Biodegradation of LAS in the mesophilic reactor was at the same level as in the thermophilic reactor under stable conditions.

  2. Anaerobic bioprocessing of sewage sludge, focusing on degradation of linear alkylbenzene sulfonates (LAS).

    PubMed

    Angelidaki, I; Toräng, L; Waul, C M; Schmidt, J E

    2004-01-01

    Anaerobic degradation of sludge amended with linear alkylbenzene sulfonates (LAS) was tested in a one stage continuous stirred tank reactor (CSTR) and a two stage reactor system consisting of a CSTR as first step and upflow anaerobic sludge bed (UASB) reactor as the second step. Anaerobic removal of LAS was only observed at the second step but not at the first step. Removal of LAS in the UASB reactors was approx. 80% where half was due to absorption and the other half was apparently due to biological removal as shown from the LAS mass balance. At the end of the experiment the reactors were spiked with 14C-LAS which resulted in 5.6% 14CO2 in the produced gas. Total mass balance of the radioactivity was however not achieved. In batch experiments it was found that LAS at concentrations higher than 50 mg/l is inhibitory for most microbial groups of the anaerobic process. Therefore, low initial LAS concentration is a prerequisite for successful LAS degradation. The results from the present study suggest that anaerobic degradation of LAS is possible in UASB reactors when the concentration of LAS is low enough to avoid inhibition of microorganisms active in the anaerobic process.

  3. LAS homolog distribution shift during wastewater treatment and composting ecological implications

    SciTech Connect

    Prats, D.; Ruiz, F.; Vazquez, B.; Zarzo, D. . Div. Chemical Engineering); Berna, J.L.; Moreno, A. )

    1993-09-01

    The behavior of LAS (linear alkylbenzene sulfonate) in different environmental compartments was studied through wastewater treatment process steps in sewage treatment plants of Alicante and Benidorm (activated sludge type) as well as in Guardamar (lagoons). The fate of LAS, using a specific HPLC method, was monitored during treatment sludge compostage and soil amendment operations. Finally, the marine sediments close to a submarine wastewater sewer outfall were analyzed. The results show significant differences between distribution of LAS homologs in water and solids (sludges, sediments, and soils), as compared to the original distribution in detergent formulations, yielding a lower LAS average molecular weight in water samples. The change observed in the homolog distribution of LAS implies a reduction in the toxicity to Daphnia, because a lower average molecular weight of LAS is less toxic.

  4. Unnatural pregnancy deaths in Las Vegas: A descriptive study.

    PubMed

    Mahesan Paul, Anthea B; Simms, Lary; Paul, Abraham Ebenezer; Yorke, Jojo; Saroya, Tarnjot; Schmidseder, Christopher; Mahesan, Andrew A; Mahesan, Arnold M

    2016-11-01

    This study reports descriptive data assessing the prevalence of various risk factors and associations among pregnancy-related death by unnatural causes (PRUD), namely suicide, homicide and accidental causes in the city of Las Vegas. In 7215 women referred for autopsy, results showed PRUD 0.1% (n = 37) was more common in the Caucasian race 45.9% (n = 17), and ages 20-30 years 43.2% (n = 16). We also identified high prevalence of mental illness 51.3% (n = 19) and low prenatal care 37.8% (n = 14), particularly in our suicide cohort 100.0% (n = 13), and 15.3% (n = 2) respectively. Our study demonstrates the first investigation to identify the relationship between mental illness, particularly mood and substance disorders with pregnancy-related unnatural death.

  5. Proteus aircraft over Las Cruces International Airport in New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  6. Proteus aircraft low-level flyby at Las Cruces Airport.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  7. Proteus in flight over mountains near Las Cruces, New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  8. City of Las Vegas Plug-in Hybrid Electric Vehicle Demonstration Program

    SciTech Connect

    2013-12-31

    The City of Las Vegas was awarded Department of Energy (DOE) project funding in 2009, for the City of Las Vegas Plug-in Hybrid Electric Vehicle Demonstration Program. This project allowed the City of Las Vegas to purchase electric and plug-in hybrid electric vehicles and associated electric vehicle charging infrastructure. The City anticipated the electric vehicles having lower overall operating costs and emissions similar to traditional and hybrid vehicles.

  9. Explicación de las disparidades raciales en la salud neonatal en Brasil*

    PubMed Central

    Nyarko, Kwame A.; López-Camelo, Jorge; Castilla, Eduardo E.; Wehby, George L.

    2015-01-01

    Objetivos. Buscamos cuantificar la manera en que los efectos socioeconómicos, demográficos, geográficos y de atención de salud explican las disparidades raciales en las tasas de bajo peso al nacer y prematuridad en Brasil. Métodos. Utilizamos una muestra de 8 949 niños nacidos entre 1995 y el 2009 en 15 ciudades y 7 provincias de Brasil. Nos centramos en las disparidades en la prevalencia de bajo peso al nacer (< 2 500 g) y prematuridad (< 37 semanas de gestación) en recién nacidos de ascendencia solo africana o mezclada con otras ascendencias y de ascendencia solo europea. Usamos un modelo de descomposición para cuantificar la contribución de los factores conceptualmente pertinentes a esas disparidades. Resultados. El modelo permitió explicar entre 45% y 94% de las disparidades en cuanto al bajo peso al nacer y entre 64% y 94% de las disparidades en cuanto a la prematuridad entre los grupos de ascendencia africana y de ascendencia europea. Las diferencias en el uso de atención prenatal y en la ubicación geográfica fueron los factores más importantes, seguidos por las diferencias socioeconómicas. El modelo permitió explicar la mayoría de las disparidades en los recién nacidos de ascendencia africana mezclada y parte de las disparidades en los de ascendencia solo africana. Conclusiones. En las políticas públicas para mejorar la salud infantil se deben abordar las diferencias en cuanto a la atención prenatal y la ubicación geográfica a fin de reducir las disparidades en materia de salud entre los recién nacidos de ascendencia africana y los de ascendencia europea en Brasil.

  10. Environmental levels of Linear alkylbenzene Sulfonates (LAS) in sediments from the Tagus estuary (Portugal): environmental implications.

    PubMed

    Hampel, M; Canário, J; Branco, V; Vale, C; Blasco, J

    2009-02-01

    Sediments from the Tagus estuary (Portugal) were collected at 40 stations in July and December 2004. Total LAS concentrations ranged between 0.03 and 17.76 mg LAS.kg(-1) dry weight in July, and between 0.09 and 9.57 mg LAS.kg(-1) in December. Highest LAS concentrations were found at the upper northern part of the estuary, coincident with the localisation of an important waste water treatment station. According to the Predicted No Effect Concentration (PNEC) of 8.1 mg.kg(-1) derived for this compound, Environmental Risk Assessment (ERA) identified a hazard for the ecosystem at the station with the highest LAS concentration, and similar results are obtained by Equilibrium Partitioning Method (EPM). Nevertheless, LAS concentrations decreased significantly between samplings in the stations with the highest LAS concentrations in July, whereas increased LAS concentrations at adjacent stations were found in December. In the remaining stations, LAS concentrations were up to three orders of magnitude lower, representing no hazard for the sediment community.

  11. Stationary Phase-Specific Virulence Factor Overproduction by a lasR Mutant of Pseudomonas aeruginosa

    PubMed Central

    Cabeen, Matthew T.

    2014-01-01

    Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not. PMID:24533146

  12. Las propiedades de las estrellas extrañas en el marco de una nueva ecuación de estado para la materia extraña

    NASA Astrophysics Data System (ADS)

    Lugones, G.; Benvenuto, O. G.

    Se estudian las propiedades generales de las estrellas constituídas por materia extraña (ME) en el marco de una nueva ecuación de estado (EOS) en la que consideramos la masa de los quarks como dependiente del número medio de bariones por unidad de volumen. Se asume esta dependencia de forma que los quarks sean livianos (pesados) a densidades altas (bajas). En esta aproximación, la EOS de la ME es similar a la predicha por el modelo de la Bolsa del MIT, pero es significativamente mas dura a bajas densidades. Esta propiedad modifica las propiedades de las estrellas extrañas en forma notable. Encontramos que, con esta nueva EOS, los objetos pueden ser más masivos que en el caso de la EOS de la bolsa del MIT y que, además, pueden presentar mayores redshifts gravitatorios en hasta un 10%. En el caso de las oscilaciones radiales de estos objetos, calculamos la relación período vs. redshift gravitacional y encontramos una expresión analítica simple para el caso de las oscilaciones de objetos de baja masa. Encontramos que, aún con hipótesis muy diferentes en cuanto a la ecuación de estado de la materia extraña, las propiedades generales de estos objetos no se ve afectada en forma fundamental, y, por lo tanto, no deberían ser muy diferentes de las aquí expuestas.

  13. Optimization of linear alkylbenzene sulfonate (LAS) degradation in UASB reactors by varying bioavailability of LAS, hydraulic retention time and specific organic load rate.

    PubMed

    Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Sakamoto, Isabel K; Duarte, Iolanda C S; Varesche, Maria B A

    2013-01-01

    Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT.

  14. Las Vegas Basin Seismic Response Project: Measured Shallow Soil Velocities

    NASA Astrophysics Data System (ADS)

    Luke, B. A.; Louie, J.; Beeston, H. E.; Skidmore, V.; Concha, A.

    2002-12-01

    The Las Vegas valley in Nevada is a deep (up to 5 km) alluvial basin filled with interlayered gravels, sands, and clays. The climate is arid. The water table ranges from a few meters to many tens of meters deep. Laterally extensive thin carbonate-cemented lenses are commonly found across parts of the valley. Lenses range beyond 2 m in thickness, and occur at depths exceeding 200 m. Shallow seismic datasets have been collected at approximately ten sites around the Las Vegas valley, to characterize shear and compression wave velocities in the near surface. Purposes for the surveys include modeling of ground response to dynamic loads, both natural and manmade, quantification of soil stiffness to aid structural foundation design, and non-intrusive materials identification. Borehole-based measurement techniques used include downhole and crosshole, to depths exceeding 100 m. Surface-based techniques used include refraction and three different methods involving inversion of surface-wave dispersion datasets. This latter group includes two active-source techniques, the Spectral Analysis of Surface Waves (SASW) method and the Multi-Channel Analysis of Surface Waves (MASW) method; and a new passive-source technique, the Refraction Mictrotremor (ReMi) method. Depths to halfspace for the active-source measurements ranged beyond 50 m. The passive-source method constrains shear wave velocities to 100 m depths. As expected, the stiff cemented layers profoundly affect local velocity gradients. Scale effects are evident in comparisons of (1) very local measurements typified by borehole methods, to (2) the broader coverage of the SASW and MASW measurements, to (3) the still broader and deeper resolution made possible by the ReMi measurements. The cemented layers appear as sharp spikes in the downhole datasets and are problematic in crosshole measurements due to refraction. The refraction method is useful only to locate the depth to the uppermost cemented layer. The surface

  15. A Total Water Management Analysis of the Las Vegas Wash Watershed, Nevada

    EPA Science Inventory

    Climate change, land use change, and population growth are fundamental factors affecting future hydrologic conditions in streams, especially in arid regions with scarce water resources. Located in the arid southwest, Las Vegas Valley located within the Las Vegas Wash watershed is...

  16. Problem-Solving in Las Vegas: Students Are Building Skills and a Global Network.

    ERIC Educational Resources Information Center

    Budd, Gregory; Curry, Don

    1995-01-01

    Describes a project initiated at Silverado High School in Las Vegas, where students from Las Vegas and schools across the United States monitor the levels of radon in the atmosphere. Enables students to learn first hand about the collection, analysis, and interpretation of scientific data and to network with other students from the United States…

  17. Inhibition of biogas production by alkyl benzene sulfonates (LAS) in a screening test for anaerobic biodegradability.

    PubMed

    Garcia, M Teresa; Campos, Encarna; Dalmau, Manel; Illán, Patricia; Sánchez-Leal, Joaquin

    2006-02-01

    The effect of the inoculum source on the digestion of linear alkylbenzene sulfonates (LAS) under anaerobic conditions has been investigated. The potential for primary and ultimate LAS biodegradation of anaerobic sludge samples obtained from wastewater treatment plants (WWTPs) of different geographical locations was studied applying a batch test system. It was found that only 4-22% of the LAS added to the batch anaerobic digesters was primarily transformed suggesting a poor primary degradation of the LAS molecule in anaerobic discontinuous systems. Regarding ultimate biodegradation, the addition of LAS to the batch anaerobic digesters caused a reduction on the extent of biogas production. Significant differences in the inhibition extent of the biogas production were observed (4-26%) depending on the sludge used as inoculum. Effect of the surfactant on the anaerobic microorganisms was correlated with its concentration in the aqueous phase. Sorption of LAS on anaerobic sludge affects its toxicity by depletion of the available fraction of the surfactant. LAS content on sludge was related to the total amount of calcium and magnesium extractable ions. The presence of divalent cations promote the association of LAS with anaerobic sludge reducing its bioavailability and the extent of its inhibitory effect on the biogas production.

  18. 78 FR 43772 - Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    ...., long. 114 51'13'' W.); thence counterclockwise along the 15 DME arc to the point of beginning. Area D... modifies the Las Vegas, NV, Class B airspace area to ensure the containment of large turbine-powered... midair collision in the Las Vegas, NV, terminal area. DATES: Effective Date: 0901 UTC, August 22,...

  19. Report: EPA Needs to Improve Physical Security at Its Offices in Las Vegas, Nevada

    EPA Pesticide Factsheets

    Report #10-P-0059, February 3, 2010. EPA needs to improve physical security at its Las Vegas facilities. The Las Vegas Finance Center’s (LVFC’s) server room and other key areas are susceptible to unauthorized access by personnel not a part of LVFC.

  20. FLS2 from Solanum tuberosum have interaction with FlaLas from Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus’ (Las) is a Gram-negative and phloem-limited alphaproteobacterium. Las attacks all citrus species and citrus hybrids in the genus of Citrus and other relatives, and causes a systemic disease. Currently, control of this devastating disease is extremely difficult sinc...

  1. REMOTE SENSING OF PERCHLORATE EFFECTS ON SALT CEDAR PRELIMINARY RESULTS FROM THE LAS VEGAS WASH

    EPA Science Inventory



    Sodium Perchlorate and ammonium Perchlorate, major components of solid rocket fuel, have been manufactured in the Las Vegas Valley immediately up gradient from the Las Vegas Wash, since 1945 and 1956, respectively. Measurements of emerging ground water quality in the vici...

  2. 75 FR 57289 - Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-20

    ... National Park Service Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas... of an inventory of human remains in the control of the Pioneer Historical Society of Bent County, Las... Society of Bent County professional staff in consultation with representatives of the Apache Tribe...

  3. La Noche de las Brujas Module. Nivel Primario. [The Night of the Witches Module. Primary Level.

    ERIC Educational Resources Information Center

    Espinoza, Delia

    La Noche de las Brujas (Halloween) is the topic of this primary level unit. The objectives are to enable the child to: (1) draw scenery, using his imagination, about witches, castles, and devils; (2) write compositions on witches, devils, and Halloween; (3) explain the story "La Noche de las Brujas"; (4) tell about any adventures or…

  4. LasDamas Mock Galaxy Catalogs for SDSS

    NASA Astrophysics Data System (ADS)

    McBride, Cameron; Berlind, A.; Scoccimarro, R.; Wechsler, R.; Busha, M.; Gardner, J.; van den Bosch, F.

    2009-01-01

    The statistical strength of galaxy redshift surveys, such as the Sloan Digital Sky Survey (SDSS), have ushered us into the era of precision measurements of galaxy clustering. We are now fitting physical models to measured clustering statistics. Galaxy clustering is thus in a position to directly constrain cosmological and galaxy formation theories. This paradigm shift from qualitative to quantitative demands that we understand the statistical and systematic errors in our measurements. Moreover, we must quantify the theoretical uncertainties in our models, which are no longer clearly sub-dominant to observational errors. We address this emerging need with the LasDamas project (LArge Suite of DArk MAtter Simulations) by producing an unprecedented number of independent and realistic mock galaxy catalogs. To date, we have run over 100 independent N-body realizations using a fixed cosmology and initialized using 2nd order Lagrangian perturbation theory. We populate overdensities of dark matter using the halo occupation distribution framework, designed to match both small and large scale clustering of the observed SDSS data. A series of mock galaxy catalogs matching the geometry of the final SDSS release (DR7) are created over a wide luminosity range to correspond to Main and LRG volume-limited samples. We include important observational effects, such as redshift distortions and fiber collisions. These galaxy mocks are publicly available.

  5. Anaerobic degradation pathway of linear Alkylbenzene sulfonates (LAS) in sulfate-reducing marine sediments.

    PubMed

    Lara-Martín, Pablo A; Gómez-Parra, Abelardo; Sanz, José Luis; González-Mazo, Eduardo

    2010-03-01

    Linear alkylbenzene sulfonates (LAS) are among the principal synthetic surfactants used worldwide. Their presence in the environment has been reported in a significant number of studies, and it has been generally assumed that LAS are not biotransformed in the absence of oxygen. However, laboratory experiments performed by our group using anoxic marine sediments have reported LAS degradation percentages that can reach up to 79% in 165 days. Here, we show for the first time the initial reaction metabolites (generated via fumarate addition to the LAS molecules), their biotransformation into sulfophenyl carboxylic acids (SPC), and the progressive degradation of these by successive beta-oxidation reactions. Advanced mass spectrometry has been used to carry out the identification of these compounds. This is the first time that an anaerobic degradation pathway for LAS is described, and these results represent a significant advance in understanding the final fate of these and other similar compounds in anoxic environments.

  6. Quorum-Sensing-Negative (lasR) Mutants of Pseudomonas aeruginosa Avoid Cell Lysis and Death

    PubMed Central

    Heurlier, Karin; Dénervaud, Valérie; Haenni, Marisa; Guy, Lionel; Krishnapillai, Viji; Haas, Dieter

    2005-01-01

    In Pseudomonas aeruginosa, N-acylhomoserine lactone signals regulate the expression of several hundreds of genes, via the transcriptional regulator LasR and, in part, also via the subordinate regulator RhlR. This regulatory network termed quorum sensing contributes to the virulence of P. aeruginosa as a pathogen. The fact that two supposed PAO1 wild-type strains from strain collections were found to be defective for LasR function because of independent point mutations in the lasR gene led to the hypothesis that loss of quorum sensing might confer a selective advantage on P. aeruginosa under certain environmental conditions. A convenient plate assay for LasR function was devised, based on the observation that lasR mutants did not grow on adenosine as the sole carbon source because a key degradative enzyme, nucleoside hydrolase (Nuh), is positively controlled by LasR. The wild-type PAO1 and lasR mutants showed similar growth rates when incubated in nutrient yeast broth at pH 6.8 and 37°C with good aeration. However, after termination of growth during 30 to 54 h of incubation, when the pH rose to ≥ 9, the lasR mutants were significantly more resistant to cell lysis and death than was the wild type. As a consequence, the lasR mutant-to-wild-type ratio increased about 10-fold in mixed cultures incubated for 54 h. In a PAO1 culture, five consecutive cycles of 48 h of incubation sufficed to enrich for about 10% of spontaneous mutants with a Nuh− phenotype, and five of these mutants, which were functionally complemented by lasR+, had mutations in lasR. The observation that, in buffered nutrient yeast broth, the wild type and lasR mutants exhibited similar low tendencies to undergo cell lysis and death suggests that alkaline stress may be a critical factor providing a selective survival advantage to lasR mutants. PMID:15995202

  7. Managing Floods and Resources at the Arroyo Las Positas

    SciTech Connect

    Sanchez, L; Van Hattem, M; Mathews, S

    2002-03-05

    Engineers and water resource professionals are challenged with protecting facilities from flood events within environmental resource protection, regulatory, and economic constraints. One case in point is the Arroyo Las Positas (ALP), an intermittent stream that traverses the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. Increased runoff from post-drought rainfall, upstream development, and new perennial discharges from LLNL activities have resulted in increased dry weather flows and wetland vegetation. These new conditions have recently begun to provide improved habitat for the federally threatened California red-legged frog (Rana aurora draytonii; CRLF), but the additional vegetation diminishes the channel's drainage capacity and increases flood risk. When LLNL proposed to re-grade the channel to reestablish the 100-year flood capacity, traditional dredging practices were no longer being advocated by environmental regulatory agencies. LLNL therefore designed a desilting maintenance plan to protect LLNL facility areas from flooding, while minimizing impacts to wetland resources and habitat. The result was a combination of structural upland improvements and the ALP Five Year Maintenance Plan (Maintenance Plan), which includes phased desilting in segments so that the entire ALP is desilted after five years. A unique feature of the Maintenance Plan is the variable length of the segments designed to minimize LLNL's impact on CRLF movement. State and federal permits also added monitoring requirements and additional constraints on desilting activities. Two years into the Maintenance Plan, LLNL is examining the lessons learned on the cost-effectiveness of these maintenance measures and restrictions and reevaluating the direction of future maintenance activities.

  8. LAS degradability by marine biofilms derived from seawater in Spain and Sweden.

    PubMed

    Mauffret, A; Gillan, D C; Eriksson, K M; Rottiers, A; Blasco, J; Temara, A

    2011-07-01

    Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20 μg/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100 μg/L) was then assessed in biometers at four experimental temperatures (between 6 and 21°C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n = 3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4 ± 3.9 μgLAS/L (n = 3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial acclimation therefore appeared to have been induced at environmental concentrations < 6 μgLAS/L. Environmental pre-exposure was not a pre-requisite for featuring the full consortia of LAS degraders in the biometers. The mineralization rate was described using an Arrhenius equation at experimental temperatures within the typical annual range; however, they departed from this model below this range.

  9. Effect of linear alkylbenzene sulphonates (LAS) on the anaerobic digestion of sewage sludge.

    PubMed

    Garcia, M T; Campos, E; Sánchez-Leal, J; Ribosa, I

    2006-08-01

    Batch anaerobic biodegradation tests with different alkylbenzene sulphonates (LAS) at increasing concentrations were performed in order to investigate the effect of LAS homologues on the anaerobic digestion process of sewage sludge. Addition of LAS homologues to the anaerobic digesters increased the biogas production at surfactant concentrations 5-10 g/kg dry sludge and gave rise to a partial or total inhibition of the methanogenic activity at higher surfactant loads. Therefore, at the usual LAS concentration range in sewage sludge, no adverse effects on the anaerobic digesters functioning of a wastewater treatment plant (WWTP) can be expected. The increase of biogas production at low surfactant concentrations was attributed to an increase of the bioavailability and subsequent biodegradation of organic pollutants associated with the sludge, promoted by the surfactant adsorption at the solid/liquid interface. When the available surfactant fraction in the aqueous phase instead of the nominal surfactant concentration was used to evaluate the toxicity of LAS homologues, a highly significant relationship between toxicity and alkyl chain length was obtained. Taking into account the homologue distribution of commercial LAS in the liquid phase of the anaerobic digesters of a WWTP, an EC(50) value of 14 mg/L can be considered for LAS toxicity on the anaerobic microorganisms.

  10. Orion Capsule and Launch Abort System (LAS) installed in the NASA Glenn 8x6 Supersonic Wind Tunnel f

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Orion Capsule and Launch Abort System (LAS) installed in the NASA Glenn 8x6 Supersonic Wind Tunnel for testing. This test is an Aero Acoustic test of the LAS. Pictured is the calibration of the model's angle of attack

  11. European risk assessment of LAS in agricultural soil revisited: species sensitivity distribution and risk estimates.

    PubMed

    Jensen, John; Smith, Stephen R; Krogh, Paul Henning; Versteeg, Donald J; Temara, Ali

    2007-10-01

    Linear alkylbenzene sulphonate (LAS) is used at a rate of approximately 430,000 tons/y in Western Europe, mainly in laundry detergents. It is present in sewage sludge (70-5,600 mg/kg; 5-95th percentile) because of its high usage per capita, its sorption and precipitation in primary settlers, and its lack of degradation in anaerobic digesters. Immediately after amendment, calculated and measured concentrations are <1 to 60 mg LAS/kg soil. LAS biodegrades rapidly in soil with primary and ultimate half-lives of up to 7 and 30 days, respectively. Calculated residual concentrations after the averaging time (30 days) are 0.24-18 mg LAS/kg soil. The long-term ecotoxicity to soil microbiota is relatively low (EC10 >or=26 mg sludge-associated LAS/kg soil). An extensive review of the invertebrate and plant ecotoxicological data, combined with a probabilistic assessment approach, led to a PNEC value of 35 mg LAS/kg soil, i.e. the 5th percentile (HC5) of the species sensitivity distribution (lognormal distribution of the EC10 and NOEC values). Risk ratios were identified to fall within a range of 0.01 (median LAS concentration in sludge) to 0.1 (95th percentile) and always below 0.5 (maximum LAS concentration measured in sludge) according to various scenarios covering different factors such as local sewage influent concentration, water hardness, and sewage sludge stabilisation process. Based on the present information, it can be concluded that LAS does not represent an ecological risk in Western Europe when applied via normal sludge amendment to agricultural soil.

  12. Effects of linear alkylbenzene sulfonate (LAS) on the interspecific competition between Microcystis and Scenedesmus.

    PubMed

    Zhu, Wei; Chen, Huaimin; Guo, Lili; Li, Ming

    2016-08-01

    The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20 mg L(-1)), but cell density of S. obliquus reduced when treated with higher LAS concentration (100 mg L(-1)). The growth of M. aeruginosa was inhibited markedly with 20 and 100 mg L(-1) LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100 mg L(-1). The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4-0.5 day(-1) and 0.6-0.7 day(-1), respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100 mg L(-1) LAS was about 0.2 day(-1). M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20 mg L(-1) LAS. The growth of S. obliquus treated with 20 mg L(-1) LAS was not affected significantly in single culture but was promoted by 75 % in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100 mg L(-1) LAS was promoted by more than 97 %. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems.

  13. 78 FR 32644 - Las Vegas Wash Hydro LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... Energy Regulatory Commission Las Vegas Wash Hydro LLC; Notice of Preliminary Permit Application Accepted..., 2012, Las Vegas Wash Hydro LLC, filed an application for a preliminary permit, pursuant to section 4(f) of the Federal Power Act (FPA), proposing to study the feasibility of the Las Vegas...

  14. 76 FR 37034 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of the Las Vegas, NV, Class B... of June 17, 2011, concerning a proposal to modify Class B airspace at Las Vegas, NV. The document... Gough, Manager, Airspace and Procedures, and Bill Ruggiero, Support Manager Las Vegas, TRACON,...

  15. 40 CFR 81.82 - El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false El Paso-Las Cruces-Alamogordo... Designation of Air Quality Control Regions § 81.82 El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region. The El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region (New...

  16. 78 FR 2646 - Proposed Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-14

    ... FR 65332) closed on December 26, 2012, is reopened until February 13, 2013. ADDRESSES: Send comments... of Class B Airspace; Las Vegas, NV'' (77 FR 65332). The FAA requested that comments on that...

  17. Double star images taken by HST WFPC and Las Campanas Observatory

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Comparison of the same area of sky (a double star) taken by the Hubble Space Telescope (HST) wide field planetary camera (WFPC) and ground-based image taken from the Las Campanas Observatory, Carnegie Institute of Washington.

  18. 76 FR 61379 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... public land management in New Mexico. Planned agenda items include a welcome and introduction of new... concerns in the BLM Las Cruces District and future project work for the RAC. A half-hour public...

  19. Terrestrial risk assessment for linear alkyl benzene sulfonate (LAS) in sludge-amended soils.

    PubMed

    de Wolf, W; Feijtel, T

    1998-03-01

    A comparison of the estimated environmental concentration and the effect concentrations (in the laboratory or field) in the receiving compartment form the basis of environmental risk assessments. This paper reviews processes that critically influence the fate of LAS in the terrestrial environment. Concentrations of LAS in sludge are quite high due to sorption to primary sludge, precipitation of Ca and Mg-salts of LAS, and lack of biodegradation under anaerobic digestion. This implies that when sludge is applied to soil e.g. as a fertilizer, considerable amounts of this important surfactant may enter the terrestrial environment. Influence of aerobic situations on LAS concentrations during sludge storage needs further research to allow incorporation into the risk assessment. Aerobic biodegradation in soil is considered the most important removal mechanism of LAS loading to the terrestrial environment through sludge-amendment. Sorption plays a role in determining the residence time of a chemical in the soil, hereby enabling more time for biodegradation to occur. In addition, sorption may affect the expression of effects of surfactants towards benthic and soil dwelling organisms and plants. Another factor that needs further attention is the form of LAS in the environment, which is not similar to the commercial material applied in detergents. The differential sorption and biodegradation of the LAS components lead to a shift in the alkyl chain length (homologue), and phenylisomer distribution towards increased hydrophobicity. Also, occurrence of Ca/Mg-salts in the environment versus the Na-salt for the commercial material critically impacts the extrapolation of effects data obtained in lab studies (mostly performed with the commercial material) to the field. The literature data were used in combination with strategies and methods provided by the European Union Technical Guidance Document in support of risk assessment of new and notified substances (1996) for the

  20. Best Practices Case Study: Pulte Homes and Communities of Del Webb, Las Vegas Division

    SciTech Connect

    2009-10-01

    Case study of Pulte Homes Las Vegas Division, who certified nearly 1,200 homes to the DOE Builders Challenge between 2008 and 2012. All of the homes by Las Vegas’ biggest builder achieved HERS scores of lower than 70, and many floor plans got down to the mid 50s, with ducts located in sealed attics insulated along the roof line, advanced framing, and extra attention to air sealing.

  1. LANDSAT-D assessment system library computer compatible tape (LASLIB-CCT/LAS-CCT)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The format for computer compatible tapes containing thematic mapper archival data and product data generated by the LANDSAT-D Assessment System (LAS). These data tapes are engineering products developed primarily for LAS internal use to assist in the early evaluation of thematic mapper data quality and ground data processing algorithms during the limited period of one year following the launch of LANDSAT-D.

  2. Exposure of the marine deposit feeder Hydrobia ulvae to sediment spiked with LAS congeners.

    PubMed

    Mauffret, A; Temara, A; Blasco, J

    2010-05-01

    The lethal and sub-lethal toxicity of LAS congeners to the mollusc gastropod Hydrobia ulvae were assessed in spiked sediment bioassays. This complements the little knowledge available to date on mixture effects in the sediment compartment. The LAS homologues joint effect was concentration additive ([summation operator]TU(i) = 0.8-1). As opposed to the 10-d LC10 based on the sediment associated LAS concentration (91-330 mg/kg) which was independent of the homologue chain length, the LC10 based on the dissolved LAS fraction (0.804-0.068 mg/L) decreased as the homologue chain length increased from 10 to 13 carbons. The quantitative structure-activity relationship (QSAR) derived from these data was log (1/LC10 (mol/L)) = 0.64 log K(ow) + 4.40 (n = 5; r(2) = 0.76; s = 0.24). It showed an apparent higher toxicity compared to the typical QSAR for polar narcosis in water-only systems probably due to the simultaneous exposure of the snail to LAS through the dissolved and the sediment associated fractions. The egestion rate of the surviving snails recovered after few days' exposure (1-d NOEC: 40-107 mg/kg, 9-d NOEC: 65-190 mg/kg) which suggests that the organisms were able to acclimate to LAS during the exposure.

  3. Effect of the test media and toxicity of LAS on the growth of Isochrysis galbana.

    PubMed

    Garrido-Perez, M C; Perales-VargasMachuca, J A; Nebot-Sanz, E; Sales-Márquez, D

    2008-11-01

    In this paper, the toxicity of linear alkylbenzene sulfonate (LAS) was evaluated in the marine microalga Isochrysis galbana using data of growth inhibition toxicity tests at 96-h exposure time. Toxicity was examined in standard conditions and by means of the modification of two variables of the test media: (1) the dilution water and (2) the content of nutrients in the test medium. For this purpose, a total of 10 toxicity test were designed: five dilution waters, four natural marine waters and one synthetic seawater; each in two different nutritive conditions, saturated nutrient concentration (SC) by the addition of modified f/2 nutritive medium, and natural nutrient concentration (NC), i.e., without the addition of f/2. At threshold toxicity levels, the dilution waters used in the test and the nutrient concentrations did not affect the toxicity of LAS. At IC50 concentrations, the toxicity of LAS is influenced by both variables: under SC conditions, the toxic effect of LAS diminishes, obtaining in all the tests IC50 > 10 mg/L LAS. Under NC conditions, IC50 concentrations ranging between 3.15 and 9.26 mg/L LAS have been obtained.

  4. Adsorption/desorption of linear alkylbenzenesulfonate (LAS) and azoproteins by/from activated sludge flocs.

    PubMed

    Conrad, A; Cadoret, A; Corteel, P; Leroy, P; Block, J-C

    2006-01-01

    Our study investigated the adsorption/desorption by/from activated sludge flocs, dispersed in river water or in diluted wastewater, of organic compounds (C(11)-LAS, azoalbumin and azocasein) at concentrations relevant to environmental conditions. Activated sludge flocs, used as a model of biological aggregates, are characterized by a very heterogeneous matrix able to sorb the three organic compounds tested at 4 degrees C. The adsorbed amount of C(11)-LAS by activated sludge flocs was higher than that of azocasein or azoalbumin, as shown by the Freundlich parameters (K(ads)=8.6+/-1.7, 1.6+/-0.3 and 0.3+/-0.1 micromol(1-1/n)g(-1)l(1/n) for C(11)-LAS, azocasein and azoalbumin, respectively; n=3 sludges). C(11)-LAS sorption from activated sludge appeared to be partially reversible in river water, while a marked hysteresis phenomenon was observed for azocasein and azoalbumin, implying a low degree of reversibility in their exchange between activated sludge and river water. It has also been displayed that the conductivity variation of bulk water (comprised between 214 and 838 microS cm(-1)) exerted no dramatic effect on the C(11)-LAS desorption from activated sludge flocs, while a little effect of it on azocasein desorption was observed. Thus, biological aggregates as activated sludge flocs can serve as an intermediate carrier for C(11)-LAS, while it represents a sink for proteins.

  5. Methanogenic activity inhibition by increasing the linear alkylbenzene sulfonate (LAS) concentration.

    PubMed

    Souza, Luiza F C; Florencio, Lourdinha; Gavazza, Savia; Kato, Mario T

    2016-07-02

    The effect of the initial concentration of linear alkylbenzene sulfonate (LAS) on specific methanogenic activity (SMA) was investigated in this work. Six anaerobic flasks reactors with 1 L of total volume were inoculated with anaerobic sludge (2 g VSS L(-1)). The reactors were assayed for 42 days, and fed with volatile fatty acids, nutrients, and LAS. The initial LAS concentrations were 0, 10, 30, 50, 75, and 100 mg L(-1) for the treatment flasks T1 (control), T2, T3, T4, T5, and T6, respectively. When compared with T1, T2 exhibited a 30% reduction in maximum SMA and total methane production (TMP). In treatment T3 through T6, the reductions were 44-97% (T3-T6) for SMA, and 30-90% (T3-T6) for TMP. Total LAS removal increased following the increase in the initial LAS concentration (from 36% at T1 to 76% at T6), primarily due to the high degree of sludge adsorption. LAS biodegradation also occurred (32% in all treatments), although this was most likely associated with the formation of non-methane intermediates. Greater removal by adsorption was observed in long-chain homologues, when compared to short-chain homologues (C13 > C10), whereas the opposite occurred for biodegradation (C10 > C13). The C13 homologue was adsorbed to a great extent (in mass) in T4, T5 and T6, and may also have inhibited methane formation in these treatments.

  6. A novel small molecule, LAS-0811, inhibits alcohol-induced apoptosis in VL-17A cells.

    PubMed

    Kim, Tae-Hun; Venugopal, Senthil K; Zhu, Ming; Wang, Si-Si; Lau, Derick; Lam, Kit S; Clemens, Dahn L; Zern, Mark A

    2009-02-20

    One of the pathways by which alcohol induces hepatocyte apoptosis is via oxidative stress. We screened several chemically-synthesized small molecules and found LAS-0811, which inhibits oxidative stress. In this study, we elucidated its role in inhibiting alcohol-induced apoptosis in hepatocyte-like VL-17A cells. VL-17A cells were pre-incubated with LAS-0811, followed by ethanol incubation. Ethanol-induced reactive oxygen species and apoptosis were significantly inhibited in LAS-0811 pre-treated cells. VL-17A cells were transfected with a reporter (ARE/TK-GFP) plasmid containing green fluorescent protein (GFP) as a reporter gene and the anti-oxidant response element as the promoter. LAS-0811 pre-treatment significantly induced the GFP expression compared to the cells treated with ethanol alone. LAS-0811 induced the activation of nrf2 and enhanced the expression and activity of glutathione peroxidase, one of the downstream targets of nrf2. The results indicate that LAS-0811 protects VL-17A cells against ethanol-induced oxidative stress and apoptosis at least in part via nrf2 activation.

  7. Monitoring Changes in Channel Morphology in Las Vegas Wash with Global Fiducials Program Imagery

    NASA Astrophysics Data System (ADS)

    Wheeler, D. J.

    2012-12-01

    To borrow from a popular adage, "What happens in Las Vegas [Wash], stays in Las Vegas [Wash]"—but only with a lot of help. This past decade has seen a concerted effort to curb erosion and sediment transport along the 12 mile long channel between East Las Vegas and Lake Mead. Las Vegas Wash is prototypical of an urban river in an arid environment that is being impacted by increasing urban development and impervious surface runoff within its drainage area. Rapid urbanization since the 1970s has increased the flow of water into Las Vegas Wash, causing severe channel destabilization. Within two decades millions of cubic yards of rocks and sediment were scoured out of the wash and transported downstream to Lake Mead. The wetlands that once covered over 2,000 acres within Las Vegas Wash dwindled to 200 acres in the 1990s as the channel became as much as 40 feet deeper and 300 feet wider at some points. In 1999 the Las Vegas Wash Coordination Committee (LVWCC) initiated a 20-year plan to construct erosion control structures (weirs) for channel stabilization and rock riprap for stream bank protection. The hope is to design structures that will slow down the water flow, trap sediments, and to eventually restore much of the wetland environment. Using high-resolution satellite imagery from the Global Fiducials Program Library housed at the U. S. Geological Survey, this transition is being tracked from 1999 to the present. From November 1999 to July 2008 new residential and commercial development has claimed an additional 12 square kilometers (3000 acres) of land in Henderson, NV, along the south side of Las Vegas Wash. Even with the increased volume of surface and groundwater runoff entering the wash, current sediment yields are much lower than the 1999 totals. The imagery documents the construction of 14 of the 22 LVWCC planned weirs by the year 2011. It also shows many miles of stream bank stabilization by riprap, planting of riparian vegetation and placing of

  8. Environmentally Endemic Pseudomonas aeruginosa Strains with Mutations in lasR Are Associated with Increased Disease Severity in Corneal Ulcers

    PubMed Central

    Hammond, John H.; Hebert, Wesley P.; Naimie, Amanda; Ray, Kathryn; Van Gelder, Rachel D.; DiGiandomenico, Antonio; Lalitha, Prajna; Srinivasan, Muthiah; Acharya, Nisha R.; Lietman, Thomas; Hogan, Deborah A.

    2016-01-01

    ABSTRACT The Steroids for Corneal Ulcers Trial (SCUT) was a multicenter, international study of bacterial keratitis in which 101 Pseudomonas aeruginosa infections were treated. Twenty-two of 101 P. aeruginosa isolates collected had a colony morphology characteristic of a loss-of-function mutation in lasR, the gene encoding a quorum-sensing master regulator. Ulcers caused by these 22 strains were associated with larger areas of corneal opacification, worse vision, and a lower rate of vision recovery in response to treatment than ulcers caused by the other isolates. The lasR sequences from these isolates each contained one of three nonsynonymous substitutions, and these strains were deficient in production of LasR-regulated protease and rhamnolipids. Replacement of lasR with either of the two most common lasR alleles from the SCUT isolates was sufficient to decrease protease and rhamnolipid production in PA14. Loss of LasR function is associated with increased production of CupA fimbriae, and the LasR-defective isolates exhibited higher production of CupA fimbriae than LasR-intact isolates. Strains with the same lasR mutation were of the same multilocus sequence type, suggesting that LasR-deficient, environmental P. aeruginosa strains were endemic to the area, and infections caused by these strains were associated with worse patient outcomes in the SCUT study. (This study has been registered at ClinicalTrials.gov under registration no. NCT00324168.) IMPORTANCE The LasR transcription factor is an important regulator of quorum sensing in P. aeruginosa and positively controls multiple virulence-associated pathways. The emergence of strains with lasR loss-of-function alleles in chronic disease is well described and is thought to represent a specific adaptation to the host environment. However, the prevalence and virulence of these strains in acute infections remain unclear. This report describes observations revealing that lasR mutants were common among isolates from

  9. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa.

    PubMed

    Feltner, John B; Wolter, Daniel J; Pope, Christopher E; Groleau, Marie-Christine; Smalley, Nicole E; Greenberg, E Peter; Mayer-Hamblett, Nicole; Burns, Jane; Déziel, Eric; Hoffman, Lucas R; Dandekar, Ajai A

    2016-10-04

    Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR.

  10. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa

    PubMed Central

    Feltner, John B.; Wolter, Daniel J.; Pope, Christopher E.; Groleau, Marie-Christine; Smalley, Nicole E.; Greenberg, E. Peter; Mayer-Hamblett, Nicole; Burns, Jane; Hoffman, Lucas R.

    2016-01-01

    ABSTRACT Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR. PMID:27703072

  11. El fenotipo de las mucinas en el esófago de Barrett

    PubMed Central

    Torrado, Julio; Piazuelo, María Blanca; Ruiz, Irune; Izarzugaza, María Isabel; Camargo, María Constanza; Delgado, Alberto; Abdirad, Afshin; Correa, Pelayo

    2011-01-01

    Antecedentes El esófago de Barrett es una reconocida lesión precursora de adenocarcinoma esofágico. Aunque generalmente asociada al reflujo gastroesofágico, los mecanismos patogénicos de la enfermedad no son bien conocidos. El objetivo del presente estudio es explorar la historia natural e identificar marcadores de progreso del proceso precanceroso. Material y métodos Se utilizaron cortes histológicos de 67 especímenes de esófago correspondientes a 14 pacientes con esófago de Barrett, a los que se siguió entre 1 – 9 años. Se clasificaron las lesiones en: esófago de Barrett sin displasia, indefinido para displasia o con displasia. Se evaluó la expresión de diferentes mucinas en las células caliciformes y en las columnares usando técnicas de histoquímica e inmunohistoquímica. Resultados En todos los casos se comprobó la presencia de metaplasia intestinal incompleta. Las células columnares dentro del epitelio metaplásico contenían mucinas neutras. A mayor severidad de la lesión se encontró significativamente menor expresión de sialomucinas en las células columnares (p de tendencia igual a 0,03). En sujetos con lesiones indefinidas para displasia se observó un mayor contenido de sulfomucinas en las células caliciformes (p=0,034) y de MUC2 en las células columnares (p=0,029) que en sujetos con esófago de Barrett sin displasia. Se observó expresión de la mucina intestinal MUC2 y de la mucina gástrica MUC5AC en todas las muestras. MUC6, una mucina de las glándulas profundas gástricas, se presentó ocasionalmente. Conclusión La evaluación de los perfiles de mucinas en el esófago de Barrett sugiere una transición gradual del fenotipo del epitelio metaplásico a medida que la lesión avanza en el tiempo. PMID:21804831

  12. Evaluation of Linear Alkylbenzene Sulfonate (LAS) behaviour in agricultural soil through laboratory continuous studies.

    PubMed

    Oliver-Rodríguez, B; Zafra-Gómez, A; Reis, M S; Duarte, B P M; Verge, C; de Ferrer, J A; Pérez-Pascual, M; Vílchez, J L

    2015-07-01

    The behaviour of Linear Alkylbenzene Sulfonate (LAS) in agricultural soil is investigated in the laboratory using continuous-flow soil column studies in order to simultaneously analyze the three main underlying phenomena (adsorption/desorption, degradation and transport). The continuous-flow soil column experiments generated the breakthrough curves for each LAS homologue, C10, C11, C12 and C13, and by adding them up, for total LAS, from which the relevant retention, degradation and transport parameters could be estimated, after proposing adequate models. Several transport equations were considered, including the degradation of the sorbate in solution and its retention by soil, under equilibrium and non-equilibrium conditions between the sorbent and the sorbate. In general, the results obtained for the estimates of those parameters that were common to the various models studied (such as the isotherm slope, first order degradation rate coefficient and the hydrodynamic dispersion coefficient) were rather consistent, meaning that mass transfer limitations are not playing a major role in the experiments. These three parameters increase with the length of the LAS homologue chain. The study will provide the underlying conceptual framework and fundamental parameters to understand, simulate and predict the environmental behaviour of LAS compounds in agricultural soils.

  13. Cystic fibrosis-adapted Pseudomonas aeruginosa quorum sensing lasR mutants cause hyperinflammatory responses.

    PubMed

    LaFayette, Shantelle L; Houle, Daniel; Beaudoin, Trevor; Wojewodka, Gabriella; Radzioch, Danuta; Hoffman, Lucas R; Burns, Jane L; Dandekar, Ajai A; Smalley, Nicole E; Chandler, Josephine R; Zlosnik, James E; Speert, David P; Bernier, Joanie; Matouk, Elias; Brochiero, Emmanuelle; Rousseau, Simon; Nguyen, Dao

    2015-07-01

    Cystic fibrosis lung disease is characterized by chronic airway infections with the opportunistic pathogen Pseudomonas aeruginosa and severe neutrophilic pulmonary inflammation. P. aeruginosa undergoes extensive genetic adaptation to the cystic fibrosis (CF) lung environment, and adaptive mutations in the quorum sensing regulator gene lasR commonly arise. We sought to define how mutations in lasR alter host-pathogen relationships. We demonstrate that lasR mutants induce exaggerated host inflammatory responses in respiratory epithelial cells, with increased accumulation of proinflammatory cytokines and neutrophil recruitment due to the loss of bacterial protease- dependent cytokine degradation. In subacute pulmonary infections, lasR mutant-infected mice show greater neutrophilic inflammation and immunopathology compared with wild-type infections. Finally, we observed that CF patients infected with lasR mutants have increased plasma interleukin-8 (IL-8), a marker of inflammation. These findings suggest that bacterial adaptive changes may worsen pulmonary inflammation and directly contribute to the pathogenesis and progression of chronic lung disease in CF patients.

  14. Identification of methyl triclosan and halogenated analogues in male common carp (Cyprinus carpio) from Las Vegas Bay and semipermeable membrane devices from Las Vegas Wash, Nevada.

    PubMed

    Leiker, Thomas J; Abney, Sonja R; Goodbred, Steven L; Rosen, Michael R

    2009-03-01

    Methyl triclosan and four halogenated analogues have been identified in extracts of individual whole-body male carp (Cyprinus carpio) tissue that were collected from Las Vegas Bay, Nevada, and Semipermeable Membrane Devices (SPMD) that were deployed in Las Vegas Wash, Nevada. Methyl triclosan is believed to be the microbially methylated product of the antibacterial agent triclosan (2, 4, 4'-trichloro-4-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5, Irgasan DP300). The presence of methyl triclosan and four halogenated analogues was confirmed in SPMD extracts by comparing low- and high-resolution mass spectral data and Kovats retention indices of methyl triclosan with commercially obtained triclosan that was derivatized to the methyl ether with ethereal diazomethane. The four halogenated analogues of methyl triclosan detected in both whole-body tissue and SPMD extracts were tentatively identified by high resolution mass spectrometry. Methyl triclosan was detected in all 29 male common carp from Las Vegas Bay with a mean concentration of 596 microg kg(-1) wet weight (ww) which is more than an order of magnitude higher than previously reported concentrations in the literature. The halogenated analogs were detected less frequently (21%-76%) and at much lower concentrations (<51 microg kg(-1) ww). None of these compounds were detected in common carp from a Lake Mead reference site in Overton Arm, Nevada.

  15. Identification of methyl triclosan and halogenated analogues in male common carp (Cyprinus carpio) from Las Vegas Bay and semipermeable membrane devices from Las Vegas Wash, Nevada

    USGS Publications Warehouse

    Leiker, T.J.; Abney, S.R.; Goodbred, S.L.; Rosen, Michael R.

    2009-01-01

    Methyl triclosan and four halogenated analogues have been identified in extracts of individual whole-body male carp (Cyprinus carpio) tissue that were collected from Las Vegas Bay, Nevada, and Semipermeable Membrane Devices (SPMD) that were deployed in Las Vegas Wash, Nevada. Methyl triclosan is believed to be the microbially methylated product of the antibacterial agent triclosan (2, 4, 4'-trichloro-4-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5, Irgasan DP300). The presence of methyl triclosan and four halogenated analogues was confirmed in SPMD extracts by comparing low- and high-resolution mass spectral data and Kovats retention indices of methyl triclosan with commercially obtained triclosan that was derivatized to the methyl ether with ethereal diazomethane. The four halogenated analogues of methyl triclosan detected in both whole-body tissue and SPMD extracts were tentatively identified by high resolution mass spectrometry. Methyl triclosan was detected in all 29 male common carp from Las Vegas Bay with a mean concentration of 596????g kg- 1 wet weight (ww) which is more than an order of magnitude higher than previously reported concentrations in the literature. The halogenated analogs were detected less frequently (21%-76%) and at much lower concentrations (< 51????g kg- 1 ww). None of these compounds were detected in common carp from a Lake Mead reference site in Overton Arm, Nevada.

  16. Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) Aircraft Measurements of CO2

    NASA Technical Reports Server (NTRS)

    Christensen, Lance E.; Spiers, Gary D.; Menzies, Robert T.; Jacob, Joseph C.; Hyon, Jason

    2011-01-01

    The Jet Propulsion Laboratory Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) utilizes Integrated Path Differential Absorption (IPDA) at 2.05 microns to obtain CO2 column mixing ratios weighted heavily in the boundary layer. CO2LAS employs a coherent detection receiver and continuous-wave Th:Ho:YLF laser transmitters with output powers around 100 milliwatts. An offset frequency-locking scheme coupled to an absolute frequency reference enables the frequencies of the online and offline lasers to be held to within 200 kHz of desired values. We describe results from 2009 field campaigns when CO2LAS flew on the Twin Otter. We also describe spectroscopic studies aimed at uncovering potential biases in lidar CO2 retrievals at 2.05 microns.

  17. Sobre las soluciones acotadas del problema instantáneo de dos cuerpos

    NASA Astrophysics Data System (ADS)

    Altavista, C.

    La demostración se basa en el hecho de que las integrales del problema de los N-cuerpos admiten componentes en el campo complejo según las raíces n-ésimas de la unidad. Definida la matriz unitaria correspondiente, la fórmula de Cayley permite transformar la matriz unitaria en una matriz hermitiana. Utilizando como parámetros los cosenos direccionales de un sistema de coordenadas orbitales referidos a un sistema de referencia fijo, puede construirse, utilizando el operador hermitiano antes definido, una forma cuadrática cuyas raíces mínima y máxima definen las cotas respectivas de los movimientos de los mencionados cosenos direccionales.

  18. Estudio de la transparencia de las nubes de Magallanes a partir de la observación espectroscópica de galaxias ubicadas en dirección a las mismas

    NASA Astrophysics Data System (ADS)

    Dutra, C.; Bica, E.; Clariá, J. J.; Piatti, A. E.:

    Se presentan los primeros resultados obtenidos a partir de observaciones espectroscópicas de galaxias ubicadas en dirección a las Nubes de Magallanes. Los espectros fueron obtenidos con el telescopio de 2.15 m del CASLEO y cubren el rango 3500-7000 Å. El material observacional recolectado permite examinar poblaciones estelares y determinar el enrojecimiento interestelar que afecta a cada una de las galaxias. La distribución angular de la muestra de galaxias observadas permite efectuar el mapeamiento del enrojecimiento que afecta las distintas regiones de las Nubes de Magallanes.

  19. Bioconcentration of the anionic surfactant linear alkylbenzene sulfonate (LAS) in the marine shrimp Palaemonetes varians: a radiotracer study.

    PubMed

    Renaud, Florent; Warnau, Michel; Oberhänsli, François; Teyssié, Jean-Louis; Temara, Ali; Rouleau, Claude; Metian, Marc

    2014-08-15

    Uptake and depuration kinetics of dissolved [(14)C]C₁₂-6-linear alkylbenzene sulfonate (LAS) were determined in the shrimp Palaemonetes varians using environmentally relevant exposure concentration. The shrimp concentrated LAS from seawater with a mean BCF value of 120 L kg(-1) after a 7-day exposure. Uptake biokinetics were best described by a saturation model, with an estimated BCFss, of 159 ± 34 L kg(-1), reached after 11.5 days. Shrimp weight influenced significantly BCF value with smaller individuals presenting higher affinity to LAS. To the light of a whole body autoradiography, major accumulation of LAS occurred in the cephalothorax circulatory system (gills, heart, hepatopancreas) and ocular peduncle, but not in the flesh, limiting potential transfer to human consumers. LAS depuration rate constant value of the shrimp was 1.18 ± 0.08 d(-1) leading to less than 1% of remaining LAS in its tissues after 8 days of depuration.

  20. El aprendizaje significativo en las ciencias al participar en proyectos de investigacion cientifica

    NASA Astrophysics Data System (ADS)

    Mora Polanco, Miguelena

    La ciencia es el eje fundamental a traves del cual se desarrollan las habilidades necesarias para el pensar cientifico que va a la busqueda del conocimiento cientifico. La intencion de este estudio fue indagar en el tema de investigacion cientifica desde el punto de vista de los participantes en los siguientes aspectos relacionados con la experiencia de investigacion cientifica: a) conceptos, b) proceso, c) destrezas y d) disposicion. Tambien se analizaron: a) las perspectivas del metodo cientifico, b) la estrategia de ensenanza, c) la cultura cientifica y d) la exposicion del proyecto investigativo en la Feria Cientifica; como parte del aprendizaje significativo de la ciencias de los participantes. Esta investigacion cualitativa propuso como diseno el estudio de caso. Los aspectos relacionados a la experiencia de participar en proyecto de investigacion cientifica son el fenomeno o caso bajo estudio. En el estudio participaron cinco (5) estudiantes egresados de escuela publica o privada que cursaban hasta el tercer ano de estudios universitarios, conducentes a un bachillerato en educacion secundaria en ciencias o en ciencias naturales. Las tecnicas utilizadas para recopilar los datos fueron: analisis de documentos del DEPR, revision de artefactos y entrevistas profundas. Para el analisis de los datos de las entrevistas se utilizo el modelo de Wolcott (1994). Del analisis de documentos del DEPR se identificaron areas a mejorar en las guias de las cartas circulares con relacion a la investigacion escolar y la feria cientifica. El analisis de los artefactos proveyo evidencia de como los internados, simposios e investigaciones fomentan el que los estudiantes se superen en el aspecto cognitivo, se conviertan en creadores del conocimiento, al hacer suyo los conceptos para poder explicarlos al publico. De las entrevistas los participantes manifestaron que la experiencia de investigacion fue una de aprendizaje significativo que los marco para toda la vida y les expandio su

  1. A reinterpretation of the Pleistocene human and faunal association at Las Buitreras Cave, Santa Cruz, Argentina

    NASA Astrophysics Data System (ADS)

    Borrero, Luis A.; Martin, Fabiana M.

    2008-12-01

    The faunal assemblage recovered from Layers VIII-VII at Las Buitreras Cave has been considered as associated with human artifacts. On that basis, the previous analysis had concluded that human hunters had exploited ground sloths at the end of the Pleistocene. A reanalysis of the bones as well as the rest of the evidence suggests that there is no basis for that conclusion. On the contrary, it is suggested here that the lower layers at Las Buitreras are the result of the use of the cave as a den by ground sloths.

  2. Las fulguraciones como manifestación de reconexión en el campo magnético solar

    NASA Astrophysics Data System (ADS)

    Bagalá, L. G.; Mandrini, M. C.; Rovira, M. G.; Démoulin, P.

    Las fulguraciones solares son fenómenos transitorios de liberación de energía que se desarrollan en las estructuras magnéticas de las regiones activas del Sol. Las fulguraciones pueden llegar a liberar hasta 1032 erg en 100 seg. en todo el rango electromagnético, y acelerar partículas. En este trabajo mostramos que la ubicación de los abrillantamientos en Hα de diversas fulguraciones está relacionado con las propiedades de las conexiones de las líneas del campo magnético de la región, como se espera por las teorías de reconexión en 3D recientemente desarrolladas (Démoulin et al, 1996a). El campo magnético coronal se extrapola del campo fotosférico observado suponiendo una configuración libre de fuerzas lineal. Por medio de un algoritmo se determinan las regiones donde existe un cambio drástico en la conectividad de las líneas de campo (límites ``cuasi-discontinuos'', o cuasi-separatrices CS). Las CS son bandas abiertas que identifican zonas donde el campo magnético se reconectará con más probabilidad y, siempre que las mismas sean lo suficientemente finas, se producirá allíla liberación de energía proveniente del campo magnético. Hemos encontrado que en todas las regiones fulgurantes estudiadas (Démoulin et al, 1996b) existen CS en los mismos lugares donde se observaron los abrillantamientos en Hα. Allídonde coinciden los abrillantamientos con las CS, éstas tienen un espesor menor que 1 Mm. Las líneas de campo coronales extrapoladas de nuestro modelo tienen sus orígenes fotosféricos a ambos lados de las CS, como se espera dados los recientes estudios de reconexión magnética en 3D. Estos resultados ponen a prueba los modelos presentes sobre fulguraciones solares.

  3. Omega-oxygenation of the alkyl sidechain of linear alkylbenzenesulfonate (LAS) surfactant in Parvibaculum lavamentivorans(T).

    PubMed

    Schleheck, David; Cook, Alasdair M

    2005-09-01

    Parvibaculum lavamentivorans (T) DS-1, an aerobic, heterotrophic bacterium, requires a biofilm on a solid surface (e.g. glass particles) when utilizing commercial linear alkylbenzenesulfonate surfactant (LAS; 20 congeners) for growth. Catabolism involves the undefined 'omega-oxygenation' and beta-oxidation of the LAS side chain, and the organism excretes sulfophenyl carboxylates (SPC) quantitatively. A 3.5-l fermenter was developed which allowed gram-quantities of LAS-grown cells to be grown and harvested from medium with glass particles as the solid support. The catabolism of LAS was dominant: in diauxie experiments with acetate as second carbon source, LAS was utilized first. The biofilm-encoated LAS-grown cells were unsuitable for metabolic work in vitro because cell suspensions clumped and were not disrupted effectively, but the degradative enzymes were found to be expressed constitutively in acetate-grown cells, which formed no biofilm. LAS-dependent oxygen uptake was measured in acetate-grown cells at about 0.6 mkat (kg protein)(-1), but not in extracts of cells. Whole cells converted LAS to SPC in the presence of molecular oxygen only, and the reaction could be saturably inhibited by metyrapone, which acts on e.g. cytochromes P450 (CYP). However, despite the presence of CYP153-like sequences in the genome of strain DS-1(T), the difference spectra did not support the presence of a CYP in crude extracts, and the nature of the LAS-oxygenase remains unclear.

  4. Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression.

    PubMed Central

    Gambello, M J; Iglewski, B H

    1991-01-01

    We report the discovery of the lasR gene, which positively regulates elastase expression in Pseudomonas aeruginosa PAO1. The lasR gene was cloned by its ability to restore a positive elastase phenotype in strain PA103, a strain which possesses the elastase structural gene (lasB) but fails to synthesize the enzyme. Nucleotide sequence analysis revealed an open reading frame of 716 nucleotides encoding a protein of approximately 27 kDa. A labeled LasR protein of 27 kDa was detected in Escherichia coli by using a T7 RNA polymerase expression system. A chromosomal deletion mutant of the lasR gene was constructed in PAO1 by gene replacement. This mutant (PAO-R1) is devoid of elastolytic activity and elastase antigen. The deduced amino acid sequence of LasR is 27% homologous to the positive activator LuxR of Vibrio fischeri and the suspected activator 28K-UvrC of E. coli. Northern (RNA) analysis of total cellular RNA from PAO1, PAO-R1, and PAO-R1 containing the lasR gene on a multicopy plasmid (pMG1.7) revealed that a functional lasR gene is required for transcription of the elastase structural gene (lasB). Images PMID:1902216

  5. Hydrologic impacts of climate change and urbanization in Las Vegas Wash Watershed, Nevada

    EPA Science Inventory

    In this study, a cell-based model for the Las Vegas Wash (LVW) Watershed in Clark County, Nevada, was developed by combining the traditional hydrologic modeling methods (Thornthwaite’s water balance model and the Soil Conservation Survey’s Curve Number method) with the pixel-base...

  6. Changes in the morphometry of Las Vegas Wash and the impact on water quality

    USGS Publications Warehouse

    Roline, Richard A.; Sartoris, James J.

    1988-01-01

    Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mean. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed.

  7. The Development of Child Subjectivity in "La lengua de las mariposas"

    ERIC Educational Resources Information Center

    Ryan, Lorraine

    2012-01-01

    Jose Luis Cuerda's film "La lengua de las mariposas" is set in rural Galicia in the immediate lead-up to the outbreak of the Spanish Civil War. It portrays the tender relationship between a Republican schoolteacher, Don Gregorio, and a boy named Moncho. Upon the Nationalist capture of the town, the young Moncho hurls stones at his…

  8. Effect of linear alkylbenzene sulfonate (LAS) on human intestinal Caco-2 cells at non cytotoxic concentrations.

    PubMed

    Bradai, Mohamed; Han, Junkyu; Omri, Abdelfatteh El; Funamizu, Naoyuki; Sayadi, Sami; Isoda, Hiroko

    2016-08-01

    Linear alkylbenzene sulfonate (LAS) is a cytotoxic synthetic anionic surfactant widely present in the environment due to its large-scale production and intensive use in the detergency field. In this study, we investigated the effect of LAS (CAS No. 25155-30-0) at non cytotoxic concentrations on human intestinal Caco-2 cells using different in vitro bioassays. As results, LAS increased Caco-2 cell proliferation at concentrations ranging from 1 to 15 ppm, more significantly for shorter exposure time (24 h), confirmed using flow cytometry and trypan blue exclusion methods. Moreover, proteomics analysis revealed that this effect was associated with an over-expression of elongation factor 2 and dipeptidyl peptidase 3, and a down-regulation of 14-3-3 protein theta, confirmed at mRNA level using real-time PCR. These findings suggest that LAS at non cytotoxic concentrations, similar to those observed at wastewater treatment plants outlets, increases the growth rate of colon cancer cells, raising thereby its tumor promotion effect potential.

  9. On the fate of LAS, NPEOs and DEHP in municipal sewage sludge during composting.

    PubMed

    Pakou, Constantina; Kornaros, Michael; Stamatelatou, Katerina; Lyberatos, Gerasimos

    2009-02-01

    The fate of hydrophobic xenobiotic pollutants such as linear alkylbenzene sulfonates (LAS), nonylphenol ethoxylates (NPEO) and di-ethyl-hexyl phthalate (DEHP) during sewage sludge composting was addressed in this work. The experiments were conducted in a fully automated in-vessel autothermal composting system which was fed with a mixture of primary and secondary sludge and manure. The mixture composition was determined to achieve satisfactory humidity, C/N ratio and free air space (FAS). The effect of various parameters, such as the initial xenobiotic concentration, the presence of multiple xenobiotic compounds and the temperature of composting material sustained during the process on the xenobiotics biodegradation kinetics was investigated. It was generally established that significant xenobiotic reduction is achievable through composting under all conditions tested. According to the obtained results, the presence of LAS, NPEO and DEHP even at higher concentrations was not inhibitory to the bioprocess. However, the presence of multiple xenobiotic compounds such as NPEO, NP and DEHP in the sludge can influence LAS removal during LAS composting.

  10. Twelve Years of Sociocultural Action in the Las Villas Area. Chapter 2.

    ERIC Educational Resources Information Center

    Gonzalez, Quintin Garcia

    This chapter reports on the activities of the Rural Continuing Education Centre (CREPA), a nongovernmental organization run by volunteers from small agricultural villages in the Las Villas area of Salamanca, Spain. The organization was founded in 1983 with the goal of improving living conditions and community life for villagers through social…

  11. 75 FR 38778 - Expansion of Foreign-Trade Zone 89 Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-06

    ... [Federal Register Volume 75, Number 128 (Tuesday, July 6, 2010)] [Notices] [Page 38778] [FR Doc No: 2010-16356] DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Order No. 1688] Expansion of Foreign-Trade Zone 89 Las Vegas, NV Pursuant to its authority under the Foreign-Trade Zones Act of June 18,...

  12. PERCHLORATE UPTAKE BY SALT CEDAR (TAMARIX RAMOSISSIMA) IN THE LAS VEGAS WASH RIPARIAN ECOSYSTEM

    EPA Science Inventory

    Perchlorate ion (CIO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las vegas Wash. Perchlorate is an oxidenat, but its reduction is kineticaly hindered. CXoncern over thyrpoid effects caused the Environmental Protection Agency (EPA...

  13. 77 FR 55225 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-07

    ... (FIRS) at 1-800-877-8229 to contact the above individual during normal business hours. The FIRS is... receive a reply during normal business hours. SUPPLEMENTARY INFORMATION: The 10-member RAC advises the.... Bill Childress, District Manager, Las Cruces. BILLING CODE 4310-VC-P...

  14. Perceptions toward the Value of Higher Education for Hotel Professionals in Las Vegas: A Case Study

    ERIC Educational Resources Information Center

    Deel, Gary Lee

    2015-01-01

    This study concerns a qualitative investigation of the views toward higher education and its importance to hospitality career success among hotel professionals in the Las Vegas, Nevada area. Existing literature supported the premise that education may be important to professional career success in several different ways, and that values concerning…

  15. Orion Launch Abort System (LAS) Propulsion on Pad Abort 1 (PA-1)

    NASA Technical Reports Server (NTRS)

    Jones, Daniel S.

    2015-01-01

    This presentation provides a concise overview of the highly successful Orion Pad Abort 1 (PA-1) flight test, and the three rocket motors that contributed to this success. The primary purpose of the Orion PA-1 flight was to help certify the Orion Launch Abort System (LAS), which can be utilized in the unlikely event of an emergency on the launchpad or during mission vehicle ascent. The PA-1 test was the first fully integrated flight test of the Orion LAS, one of the primary systems within the Orion Multi-Purpose Crew Vehicle (MPCV). The Orion MPCV is part of the architecture within the Space Launch System (SLS), which is being designed to transport astronauts beyond low-Earth orbit for future exploration missions. Had the Orion PA-1 flight abort occurred during launch preparations for a real human spaceflight mission, the PA-1 LAS would have saved the lives of the crew. The PA-1 flight test was largely successful due to the three solid rocket motors of the LAS: the Attitude Control Motor (ACM); the Jettison Motor (JM); and the Abort Motor (AM). All three rocket motors successfully performed their required functions during the Orion PA-1 flight test, flown on May 6, 2010 at the White Sands Missile Range in New Mexico, culminating in a successful demonstration of an abort capability from the launchpad.

  16. Hydrogeochemical and stream sediment reconnaissance basic data for Las Cruces quadrangle, New Mexico

    SciTech Connect

    Not Available

    1981-08-31

    Field and laboratory data are presented for 501 water samples and 1817 sediment samples from the Las Cruces Quadrangle, New Mexico. The samples were collected and uranium analysis performed by Los Alamos National Laboratory; multielement analysis and data reporting were performed by the Uranium Resource Evaluation Project at Oak Ridge, Tennessee.

  17. Episodic Impacts from California Wildfires Identified in Las Vegas Near-Road Air Quality Monitoring

    EPA Science Inventory

    Air pollutant concentrations near major highways are usually attributed to a combination of nearby traffic emissions and regional background, and generally presumed to be additive in nature. During a recent year-long near-road monitoring study conducted in Las Vegas, NV, a substa...

  18. 77 FR 65332 - Proposed Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... the containment of large turbine-powered aircraft within Class B airspace, reduce air traffic... to ensure that turbine-powered aircraft operations were fully contained within the TCA (47 FR 30052... LAS Class B does not fully contain turbine-powered aircraft as required by FAA directives....

  19. Geophysical constraints on the location and geometry of the Las Vegas Shear Zone, Nevada

    USGS Publications Warehouse

    Langenheim, V.E.; Grow, J.A.; Jachens, R.C.; Dixon, G.L.; Miller, J.J.

    2001-01-01

    We model the basin configuration beneath Las Vegas Valley, Nevada, on the basis of gravity, drillhole, and seismic reflection data. We locate and characterize the various strands of the Las Vegas Valley Shear Zone (LVVSZ) by variations in basin thickness beneath the valley. The pre-Tertiary bedrock surface is complex, with subbasins buried beneath the flat alluvial surface of the valley. We suggest that these basins are formed from transtensional strain. Subbasins elongated N70??W and N50??W are interpreted as strike-slip basins. The deepest subbasin is 5 km west of Frenchman Mountain and strikes N40??E. This basin probably formed by combined movement on nonparallel strands of the LVVZ and an earlier episode of normal faulting. The basin thickness map constrains the minimum depth of the inferred detachment fault beneath Las Vegas Valley to at least 4 km. Seismic reflection data do not image a detachment fault in the upper 10 km beneath Las Vegas Valley. Our results also illustrate the utility of gravity in determining basinal structures and providing a three-dimensional perspective in areas with limited seismic reflection control.

  20. Builders Challenge High Performance Builder Spotlight - Masco Environments for Living, Las Vegas, Nevada

    SciTech Connect

    2009-01-01

    Building America Builders Challenge fact sheet on Masco’s Environments for Living Certified Green demo home at the 2009 International Builders Show in Las Vegas. The home has a Home Energy Rating System (HERS) index score of 44, a right-sized air conditi

  1. Builders Challenge High Performance Builder Spotlight - NextGen Home, Las Vegas, Nevada

    SciTech Connect

    2009-01-01

    Building America Builders Challenge fact sheet on the NextGen demo home built in Las Vegas. The home has a Home Energy Rating System (HERS) index score of 44 with R-40 spray foam attic insulation, R-40 insulated concrete walls, and a 4kW DC solar laminate

  2. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

    PubMed Central

    Weng, Lixing; Zhang, Yuqian; Yang, Yuxiang; Wang, Lianhui

    2014-01-01

    Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s) F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 μg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 μg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI) and cognate receptor (lasR and rhlR) genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s) interferes with the las system and significantly inhibits biofilm formation. PMID:24736783

  3. 75 FR 60496 - Kern Valley Railroad Company-Termination of Trackage Rights-in Las Animas County, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Surface Transportation Board Kern Valley Railroad Company--Termination of Trackage Rights--in Las Animas... milepost 0.0 and milepost 2.0 in Jansen, Las Animas County, Colo. (the line). The line traverses...

  4. Linear alkylbenzene sulfonate (LAS) in water of Lake Dianchi--spatial and seasonal variation, and kinetics of biodegradation.

    PubMed

    Wang, Zhi; Xiao, Bangding; Wu, Xingqiang; Tu, Xinhai; Wang, Yingcai; Sun, Xiaolei; Song, Lirong

    2010-12-01

    For the purpose of elucidating the environmental characteristics of anion surfactants [linear alkylbenzene sulfonates (LAS)] in the water of Lake Dianchi, a sampling investigation in the field from October 2006 to July 2007 and a batch of biodegradation experiments in the laboratory were carried out. The results showed that concentrations of LAS ranged from 18.6 to 260.1 μg L(-1), and the average concentration was 52.6 μg L(-1) in Lake Dianchi. The highest concentrations of LAS were found in the Northwest region, and the distribution of LAS varied through seasons, with much lower concentrations in fall than in any other seasons. LAS can be primarily biodegraded by microorganisms in the lake water, and the percentage of degradation was >97% after 28 days. Biodegradation of LAS was well-fitted with the kinetic model presented in this paper, and the half-lives ranged from 3.2 to 16.3 days. Temperature, pH, and initial concentrations could affect the biodegradation of LAS, among which temperature was the major factor influencing on biodegradation of LAS in water of Lake Dianchi.

  5. Effect of linear alkylbenzene sulphonate (LAS) on non-specific defence mechanisms in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Bakirel, Tülay; Keleş, Oya; Karataş, Süheyla; Ozcan, Mukaddes; Türkmen, Gülhan; Candan, Akin

    2005-01-26

    Linear alkylbenzene sulphonate (LAS) is among the most widely disseminated xenobiotics to enter waste streams and the aquatic environment. In the present investigation, we present a novel approach to evaluate in toxicity of LAS. The effects of sublethal levels (0.2 and 0.4 mg/l) of LAS on non-specific immune system, phagocytosis, respiratory burst and lyzosyme activity, and specific growth rate in the rainbow trout, Oncorhynchus mykiss, during a 54-day exposure were examined by a static bioassay test procedure. The phagocytic activity of leukocytes from fish exposed to 0.4 mg/l LAS statistically decreased compared with the control fish values. No significant reductions were observed in the extra-intracellular respiratory burst and lysozyme activities after exposure to LAS at any of the concentrations tested. The final body weight in fish groups exposed to the LAS were found to be significantly lower than in the control. The specific growth rate results also supported the result above. The results of this study showed sublethal doses (0.2-0.4 mg/l) of LAS caused to statistically insignificant suppression of non-specific immune system mechanisms excluding phagocytosis in fish at laboratory conditions. These doses of LAS may produce potential synergism on immune system when presented with other environmental pollutants.

  6. Probabilistic risk assessment for linear alkylbenzene sulfonate (LAS) in sewage sludge used on agricultural soil.

    PubMed

    Schowanek, Diederik; David, Helen; Francaviglia, Rosa; Hall, Jeremy; Kirchmann, Holger; Krogh, Paul Henning; Schraepen, Nathalie; Smith, Stephen; Wildemann, Tanja

    2007-12-01

    Deterministic and probabilistic risk assessments were developed for commercial LAS in agricultural soil amended with sewage sludge. The procedure done according to ILSI Europe's Conceptual Framework [Schowanek, D., Carr, R., David, H., Douben, P., Hall, J., Kirchmann, H., Patria, L., Sequi, P., Smith, S., Webb, S.F., 2004. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture-conceptual Framework. Regul. Toxicol. Pharmacol. 40 (3), 227-251], consists of three main steps. First, the most sensitive endpoint was determined. This was found to be the chronic ecotoxicity of LAS to soil invertebrates and plants. Additional endpoints, such as potential for plant uptake and transfer in the food chain, leaching to groundwater, surface erosion run-off, human health risk via drinking water, plant consumption and soil ingestion were also systematically evaluated but were all assessed to be of little toxicological significance. In the second step, a back-calculation was conducted from the Predicted No-Effect Concentration in soil (PNECsoil) to a safe level of LAS in sludge (here called 'Sludge Quality Standard'; SQS). The deterministic approach followed the default agricultural soil exposure scenario in the EU-Technical Guidance Document (TGD). The SQS for LAS was calculated as 49 g/kg sludge Dry Matter (DM). In order to assess the potential variability as a result of varying agricultural practices and local environmental conditions, two probabilistic exposure assessment scenarios were also developed. The mean SQS was estimated at 55 and 27.5 g/kg DM for the homogeneous soil mixing and soil injection scenarios, respectively. In the final step, the resulting SQS values were evaluated for consistency and relevance versus available information from agricultural experience and field tests. No build-up, adverse impact on soil fertility, agronomic performance, or animal/human health have been reported for agricultural

  7. Bioconcentration and toxicity of dodecylbenzene sulfonate (C12LAS) to aquatic organisms exposed in experimental streams.

    PubMed

    Versteeg, D J; Rawlings, J M

    2003-02-01

    Fish, mollusks, and crustaceans were caged in the tail pool of streams during a C(12)LAS (dodecyl benzene sulfonate) model ecosystem experimental program. Bioconcentration of total C(12)LAS and individual isomers and acute and chronic toxicity were investigated during this study. Toxicity endpoints were based on water and tissue (i.e., body burden) concentrations at which adverse effects were observed. At 32 days, total C(12)LAS bioconcentration factors (BCFs) for the fathead minnow and three invertebrate species ranged from 9 to 116. In general, bioconcentration was affected by isomer position, exposure concentration, and species. BCF values tended to decrease as isomer position moved from external (e.g., 2-phenyl) to internal (e.g., 5,6-phenyl). BCFs also decreased as exposure concentration increased. Mean acute 4-d LC(50) values ranged from 1.5 to >3.0 mg/L for the six species tested. Lethal body burdens associated with 50% mortality (LBB(50)) varied from 0.21 to 0.60 mmole/kg (wet weight). During the 32-day chronic exposures, the EC(20) values were 0.27 (0.204-0.352), 0.95 (0.597-1.29), and approximately 1.0 mg/L for Corbicula (length), Hyalella (survival), and fathead minnow (survival), respectively. At these EC(20) values, C(12)LAS body burdens were 0.035, 0.23, and 0.19 mmoles/kg wet weight in Corbicula, Hyalella, and fathead minnow, respectively. Fish exposed to wastewater treatment plant effluent had total C(12)LAS tissue concentrations ranging from 0.0005 to 0.0039 mmoles/kg wet weight. These concentrations are approximately 45-360 times below the tissue concentration associated with subtle effects in the model ecosystem stream exposures. Total C(12)LAS body burdens in feral and caged Corbicula exposed to WWTP effluents were approximately 0.0013 mmoles/kg; approximately 25-fold below concentrations associated with effects in stream exposures.

  8. The effect of specific rhlA-las-box mutations on DNA binding and gene activation by Pseudomonas aeruginosa quorum-sensing transcriptional regulators RhlR and LasR.

    PubMed

    González-Valdez, Abigail; Servín-González, Luis; Juárez, Katy; Hernandez-Aligio, Alberto; Soberón-Chávez, Gloria

    2014-07-01

    Pseudomonas aeruginosa is a free-living bacterium and an important opportunistic pathogen. The genes coding for virulence-associated traits are regulated at the level of transcription by the quorum-sensing response. In this response, the regulator LasR coupled with the autoinducer 3-oxo-dodecanoyl homoserine lactone (3O-C12-HSL) activates transcription of genes for several virulence factors. LasR/3O-C12-HSL also activates transcription of rhlR, the gene coding for the transcriptional regulator RhlR, and of rhlI that encodes the synthase that produces the autoinducer butanoyl-homoserine lactone (C4-HSL) that interacts with RhlR. Genes activated by RhlR/C4-HSL include those involved in rhamnolipids production (like the rhlAB operon) and lecA, coding for PA-I lectin. The molecular basis of LasR/3O-C12-HSL- and RhlR/C4-HSLDNA-binding specificity (at the so-called las-boxes) has not been clearly determined, and the aim of this work was to contribute to its understanding. Therefore, we analyzed the interaction of LasR and RhlR to variants of the rhlA-las-box that were constructed based on the comparison of this las-box to the las-box of lecA. We conclude that LasR and RhlR DNA-binding specificity is a complex multifactorial phenomenon in which both positive and negative effects are involved and that binding of these proteins does not necessarily result in gene activation.

  9. Reinterpretation of the stratigraphy and structure of the Rancho Las Norias area, central Sonora, Mexico

    USGS Publications Warehouse

    Page, W.R.; Harris, A.G.; Poole, F.G.; Repetski, J.E.

    2003-01-01

    New geologic mapping and fossil data in the vicinity of Rancho Las Norias, 30 km east of Hermosillo, Sonora, Mexico, show that rocks previously mapped as Precambrian instead are Paleozoic. Previous geologic maps of the Rancho Las Norias area show northeast-directed, southwest-dipping reverse or thrust faults deforming both Precambrian and Paleozoic rocks. The revised stratigraphy requires reinterpretation of some of these faults as high-angle normal or oblique-slip faults and the elimination of other faults. We agree with earlier geologic map interpretations that compressional structures have affected the Paleozoic rocks in the area, but our mapping suggests that the direction of compression is from southeast to northwest. Published by Elsevier Ltd.

  10. LANDSAT-D project ADDS/LAS. Scrounge interface control document

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The content and format of all data to be exchanged between the Applications Developmental data System (ADDS) and the LANDSAT-D Assessment System (LAS) for satisfaction of early access thematic mapper product generation requirements is specified. The ADDS provides partially processed TM data tapes on CCT's. The LANDSAT-D Assessment System processes the TM data to fully processed data tapes on 6250 bpi computer compatible tapes and provides required film data products.

  11. Comenditic and pantelleritic ash-flow tuffs from Volcan Las Navajas, Nayarit, Mexico

    SciTech Connect

    Nelson, S.A.; Hebre, J.A.

    1985-01-01

    Two distinctive ash-flow tuffs occur around the base of Volcan Las Navajas, a Pleistocene trachyte - peralkaline rhyolite center located in the northwestern segment of the Mexican Volcanic belt. The lower ash-flow unit is locally up to 65 m thick, is lithic rich and contains pumice blocks of comenditic rhyolite. The unit is not extensively exposed, and thus its areal extent and volume cannot be determined. Its chemical characteristics and stratigraphic relationship to other products erupted from Las Navajas suggest that it is related to the formation of the older of the two calderas which occur on Las Navajas. Unconformably overlying this unwelded ash-flow is a pantelleritic airfall pumice unit which is locally welded. This airfall unit is conformably overlain by a welded as-flow tuff that contains fiamme of pantelleritic composition (72 %SiO/sub 2/, 8% FeO*, 900 ppm Zr, agpaitic index of 1.7) as well as pumice blocks that show evidence of various degrees of mixing between pantellerite and trachyte. This suggests eruption from a chemically zoned magma chamber. This unit is locally up to 20 m thick, although its top has been removed by erosion. It is found on all sides of Las Navajas except on the south where it may be covered by Volcan Sanganguey, a Pleistocene to Recent calc-alkaline volcano. The welded ash-flow has been dated by K - Ar at 0.2+/-0.1 m.y. Stratigraphically and chemically this ash-flow appears to be related to the formation of younger of the two calderas.

  12. Solar hot water system installed at Las Vegas, Nevada. Final report

    SciTech Connect

    1981-01-01

    The solar hot water system installed at LaQuinta Motor Inn Inc., at Las Vegas, Nevada is described. The Inn is a three-story building with a flat roof for installation of the solar panels. The system consists of 1200 square feet of liquid flat plate collectors, a 2500 gallon insulated vertical steel storage tank, two heat exchangers and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

  13. Nondegraded metabolites arising from the biodegradation of commercial linear alkylbenzenesulfonate (LAS) surfactants in a laboratory trickling filter

    SciTech Connect

    Koelbener, P.; Baumann, U.; Leisinger, T.; Cook, A.M. |

    1995-04-01

    The degradation of a commercial linear alkylbenzenesulfonate (LAS) surfactant was examined kinetically in a trickling filter, which allowed simultaneous chemical determinations in the aqueous phase (e.g., DOC) and in the gas phase (CO{sub 2}). About 60% of the carbon applied as LAS was released as CO{sub 2}, whereas 15% remained as DOC in the eluate of acclimated trickling filters. The biomass was analyzed after the experiment, and it was found to have sorbed about 23 mg LAS/g of dry biomass; this represented about 3% of the LAS applied to the filter. The LAS and the eluates from the trickling filter were further analyzed by HPLC and UV and IR spectrometry. The residual carbon from acclimated filters contained no LAS-like material (HPLC), which was obviously subject to quantitative biotransformation. The residual material comprised > 50 polar metabolites, some of whose UV spectra differed from that of LAS, and most or all of which were sulfonated. These nondegraded metabolites included carboxylated dialkyltetralinesulfonates and sulfophenylcarboxylates. These residual materials showed no detectable toxicity to algae or Daphnia, and did not significantly lower the surface tension of water.

  14. The Las Vegas Valley Seismic Response Project: Ground Motions in Las Vegas Valley from Nuclear Explosions at the Nevada Test Site

    SciTech Connect

    Rodgers, A; Tkalcic, H; McCallen, D

    2005-03-18

    Between 2001-2004 the Las Vegas Seismic Response Project has sought to understand the response of Las Vegas Valley (LVV) to seismic excitation. In this study, the author report the findings of this project with an emphasis on ground motions in LVV from nuclear explosions at the Nevada Test Site (NTS). These ground motions are used to understand building structural response and damage as well as human perception. Historical nuclear explosion observations are augmented with earthquake recordings from a temporary deployment of seismometers to improve spatial coverage of LVV. The nuclear explosions were conducted between 1968 and 1989 and were recorded at various sites within Las Vegas. The data from past nuclear tests were used to constrain ground motions in LVV and to gain a predictive capability of ground motions for possible future nuclear tests at NTS. Analysis of ground motion data includes peak ground motions (accelerations and velocities) and amplification of basin sites relative to hard rock sites (site response). Site response was measured with the Standard Spectral Ratios (SSR) technique relative to hard rock reference sites on the periphery of LVV. The site response curves indicate a strong basin amplification of up to a factor of ten at frequencies between 0.5-2 Hz. Amplifications are strongest in the central and northern portions of LVV, where the basin is deeper than 1 km based on the reported basin depths of Langenheim et al (2001a). They found a strong correlation between amplification and basin depth and shallow shear wave velocities. Amplification below 1 Hz is strongly controlled by slowness-averaged shear velocities to depths of 30 and 100 meters. Depth averaged shear velocities to 10 meters has modest control of amplifications between 1-3 Hz. Modeling reveals that low velocity material in the shallow layers (< 200 m) effectively controls amplification. They developed a method to scale nuclear explosion ground motion time series to sites around LVV

  15. Quantifying multi-temporal urban development characteristics in Las Vegas from Landsat and ASTER data

    USGS Publications Warehouse

    Xian, G.; Crane, M.; McMahon, C.

    2008-01-01

    Urban development has expanded rapidly in Las Vegas, Nevada of the United States, over the last fifty years. A major environmental change associated with this urbanization trend is the transformation of the landscape from natural cover types to increasingly anthropogenic impervious surface. This research utilizes remote sensing data from both the Landsat and Terra-Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instruments in conjunction with digital orthophotography to estimate urban extent and its temporal changes by determining sub-pixel impervious surfaces. Percent impervious surface area has shown encouraging agreement with urban land extent and development density. Results indicate that total urban land-use increases approximately 110 percent from 1984 to 2002. Most of the increases are associated with medium-to high-density urban development. Places having significant increases in impervious surfaces are in the northwestern and southeastern parts of Las Vegas. Most high-density urban development, however, appears in central Las Vegas. Impervious surface conditions for 2002 measured from Landsat and ASTER satellite data are compared in terms of their accuracy.

  16. Surficial geology and distribution of post-impoundment sediment in Las Vegas Bay, Lake Mead

    USGS Publications Warehouse

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.; Rendigs, Richard R.

    2001-01-01

    Sidescan sonar imagery and seismic-reflection profiles were collected in the northwestern part of Las Vegas Bay to map the distribution and volume of sediment that has accumulated in this part of Lake Mead since impoundment. The mapping suggests that three ephemeral streams are the primary source of this sediment, and of these, Las Vegas Wash is the largest. Two deltas off the mouth of Las Vegas Wash formed at different lake elevations and account for 41% of the total volume of post-impoundment sediment within the study area. Deltas off the other two washes (Gypsum and Government) account for only 6% of the total volume. The sediment beyond the front of the deltas is primarily mud, and it only occurs in valley floors, where it forms a flat-lying blanket that is mostly less than 1.5 m thick. Although a thin layer, the fine-grained sediment accounts for approximately 53% of the total post-impoundment sediment volume of 5.7 x 106 m3 that has accumulated in the study area. This sediment appears to have been transported several kilometers from the river sources by density flows.

  17. Investigating Remotely Sensed Evapotranspiration in the Las Conchas and Old Fires

    NASA Astrophysics Data System (ADS)

    Poon, P.; Stewart, C.; Kinoshita, A. M.

    2015-12-01

    Wildfires significantly alter landscapes and can contribute to observed changes in hydrology. Evapotranspiration (ET) contributes significantly to the hydrologic cycle, however, there are limited studies on the impacts of fire on this variable. Using remote sensing derived products, this study explores the spatial variability of ET (specifically, the operational Simplified Surface Energy Balance (SSEBop)) within the 2011 Las Conchas Fire, New Mexico and the 2003 Old Fire, California. Following the Las Conchas Fire, spatial ET is compared with two ground-based meteorological stations and two nearby unburned stations. In the Old Fire, a simple water balance approach is used to approximate and compare watershed-scale ET pre- and post-fire. Preliminary analysis with SSEBop in Las Conchas shows relatively similar precipitation patterns while post-fire ET appears altered within high, moderate, and low burn severity areas. We will continue to evaluate the relation between post-fire ET and characteristics such as land cover, land surface temperature, and precipitation. This analysis will provide information on the application of spatial ET products to improve post-fire hydrologic estimates.

  18. Origen de los rayos cósmicos a las más altas energías

    NASA Astrophysics Data System (ADS)

    Horvath, J. E.; Gouveia dal Pino, E. M.; Medina Tanco, G. A.

    Discutimos en este trabajo la identificación de las fuentes de rayos cósmicos de las más altas energías observadas (E >= 1020 eV). Presentamos los resultados de varias simulaciones numéricas 3-D donde se calcula explícitamente el ángulo de desviación α del primario por efecto de los campos magnéticos ambientes. Con estos resultados investigamos las hipótesis de un origen extragaláctico local y halo galáctico.

  19. Variaciones seculares de período en las RR Lyrae de ω~Centauri

    NASA Astrophysics Data System (ADS)

    Marraco, H. G.; Milesi, G. E.

    Utilizando 689 observaciones de 35 estrellas RR Lyrae del cúmulo globular ω Centauri hemos obtenido nuevas determinaciones de sus períodos y sus correspondientes variaciones seculares. Las observaciones fueron obtenidas de la literatura con la excepción de un grupo 66 determinaciones que se presentan por vez primera aquí. Utilizando el parámetro testigo σ descripto en Marraco & Muzzio (Publ. Astron. Soc. Pacific 92, 700, 1980), hemos realizado un ajuste bidimensional en P y β (donde β es la variación secular del período). Con este fin la totalidad de las 689 observaciones fueron llevadas a un sistema fotométrico común. Para esto se realizó un cuidadoso análisis de los numerosos errores en la identificación de las estrellas de las series de comparación. Los resultados de los ajustes bidimensionales fueron analizados utilizando técnicas de procesamiento de imágenes. Con este fin el parámetro de ajuste σ fue representado como función de P y β. En las imágenes resultantes se buscaron los mínimos y al menor de ellos se lo aceptó como período instantáneo verdadero y su variación secular β. La determinación precisa de cada parámetro se realizó mediante ajuste de gaussianas y se determinaron sus errores. A modo de ejemplo la variable #8 fue analizada en una matriz de 501 × 501 elementos representando el parámetro σ para valores comprendidos entre 0,521034 < P < 0,521534 dias y -150×10-10 < β < +150×10-10 dias/dia. El mejor período instantáneo (correspondiente a la época DJ=2.426.908) y su variación secular son P = 0,5212859±0,0000001 días y β 14,012±,010×10-10 días/día respectivamente. Con estos valores el parámetro testigo resulta σ= 0,127 . Si no se tiene en cuenta la variación secular del período y se busca aquél de mejor ajuste para β = 0, se obtiene P = 0,5212960 días, pero entonces el parámetro de ajuste resulta tan alto como σ = 0,23 .

  20. Final Report for the Arroyo Las Positas Maintenance Impact Study, Lawrence Livermore National Laboratory

    SciTech Connect

    van Hattem, M; Paterson, L

    2006-01-12

    In 2000, the Lawrence Livermore National Laboratory's (LLNL) Environmental Protection Department, in coordination with Plant Engineering (PE), began dredging sections of the Arroyo Las Positas (ALP) to alleviate concerns about flooding of sensitive facilities within the mainsite of Lawrence Livermore National Laboratory. In order to reduce potential impacts on the federally threatened California red-legged frog (Rana aurora draytonii), LLNL proposed to dredge sections of the ALP in a ''checkerboard pattern'', resulting in a mosaic of open water habitat and vegetated sections (Figure 1). The Arroyo Las Positas Management Plan (Plan) was coordinated with both state and federal agencies including the U.S. Fish and Wildlife Service (USFWS), California Department of Fish and Game (CDF&G), San Francisco Regional Water Quality Control Board (SFRWQCB), and the Army Corp of Engineers (ACOE). Water Discharge Requirements (WDRs) were issued for this project on December 30, 1999 (Order No. 99-086) by the SFRWQCB. Provision 19 of the WDRs outlined a five-year (2000 through 2004) Maintenance Impact Study (MIS) that LLNL began in coordination with dredging work that was conducted as part of the Arroyo Las Positas Management Plan. Provision 20 of these WDRs requires LLNL to submit a final report of the results of the Maintenance Impact Study for this project to the SFRWQCB. The purpose of this report is to present the results of the Maintenance Impact Study for Arroyo Las Positas and meet the requirements of Provision 20. A description of the annual monitoring included in this Maintenance Impact Study is included in the methods section of this report. Initially the Plan called for dredging the entire length of the Arroyo Las Positas (approximately 6,981 linear feet) over a 5-year period to minimize temporal impacts on the California red-legged frog. Dredging occurred in 2000 ({approx}1,300 ft.), 2001 ({approx}800 ft.), and 2002 ({approx}1,200 ft.), which constituted approximately

  1. An Aerial Radiological Survey of Selected Areas of the City of North Las Vegas

    SciTech Connect

    Piotr Wasiolek

    2008-06-01

    As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey of selected areas of the city of North Las Vegas for the purpose of mapping natural radiation background and locating any man-made radioactive sources. Survey areas were selected in collaboration with the City Manager's office and included four separate areas: (1) Las Vegas Motor Speedway (10.6 square miles); (2) North Las Vegas Downtown Area (9.2 square miles); (3) I-15 Industrial Corridor (7.4 square miles); and (4) Future site of University of Nevada Las Vegas campus (17.4 square miles). The survey was conducted in three phases: Phase 1 on December 11-12, 2007 (Areas 1 and 2), Phase 2 on February 28, 2008 (Area 3), and Phase 3 on March 19, 2008 (Area 4). The total completed survey covered a total of 44.6 square miles. The flight lines (without the turns) over the surveyed areas are presented in Figures 1, 2, 3, and 4. A total of eight 2.5-hour-long flights were performed at an altitude of 150 ft above ground level (AGL) with 300 feet of flight-line spacing. Water line and test line flights were conducted over the Lake Mead and Government Wash areas to ensure quality control of the data. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Data, in the form of gamma energy spectra, were collected continually (every second) over the course of the survey and were geo-referenced using a differential Global Positioning System. Collection of spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man-made radioisotopes. Spectral data can also be used to identify specific radioactive isotopes. As a courtesy service, with

  2. Investigaccion-accion en la sala de clases sobre las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios y su relacion reciproca con el aprendizaje de las ciencias biologicas

    NASA Astrophysics Data System (ADS)

    Cordova-Santiago, Lizzette Astrid

    La investigacion---accion que se llevo a cabo en la sala de clases tenia como punto de partida las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios para luego examinar sus implicaciones en el proceso de aprendizaje de las Ciencias Biologicas. ¿Que se supone que hagan las creencias en relacion con el aprendizaje? ¿En que consiste incorporar este aspecto a la practica educativa universitaria? Utilizando el modelo de Kemmis y McTaggart (1987) la investigacion-accion se planteo como un proceso dinamico en cuatro momentos en espiral constituidos por la planificacion, la accion, la observacion y la reflexion. Cada una de las fases tuvo una intencion retrospectiva y prospectiva formando una espiral de autorreflexion del conocimiento y la accion. Se llevaron a cabo audio grabaciones en clases y analisis de documentos. Ademas, la profesora-investigadora hizo un portafolio para reflexionar sobre las creencias de la cultura de la ciencia que tienen los estudiantes y las creencias del aprendizaje que tiene la profesora y sobre como la comprension de estos elementos ayudo a mejorar su practica educativa a traves del tiempo. Los resultados obtenidos apuntan a que las creencias de la cultura de la ciencia que tiene el grupo de estudiantes son diversas. Ellos si creen que la ciencia tiene una cultura la cual describieron como: complicada y desconocida que evoluciona constantemente, que es un conjunto de metodos, que es altamente tecnologica, que resuelve problemas de salud, ayuda a interpretar la realidad del mundo que los rodea y su origen y que existen unas intersecciones entre la ciencia y el poder. Sobre las creencias del proceso de aprendizaje de la profesora-investigadora, estas senalan que el modelaje de actores, la vision de la academia que tiene ella asi como la participacion y negociacion entre todos los involucrados en el proceso educativo, son factores que inciden en el proceso de aprendizaje.

  3. Long-term assessment of ultrafine particles on major roadways in Las Vegas, Nevada and Detroit, Michigan

    EPA Science Inventory

    This is a presentation at the National Air Monitoring conference, given at the request of OAQPS partners. The presentation will cover ultrafine particle data collected at three locations - Las Vegas, Detroit, and Research Triangle Park.

  4. Seismic Data for Evaluation of Ground Motion Hazards in Las Vegas in Support of Test Site Readiness Ground Motion

    SciTech Connect

    Rodgers, A

    2008-01-16

    In this report we describe the data sets used to evaluate ground motion hazards in Las Vegas from nuclear tests at the Nevada Test Site. This analysis is presented in Rodgers et al. (2005, 2006) and includes 13 nuclear explosions recorded at the John Blume and Associates network, the Little Skull Mountain earthquake and a temporary deployment of broadband station in Las Vegas. The data are available in SAC format on CD-ROM as an appendix to this report.

  5. New sample treatment for determination of linear alkylbenzene sulfonate (LAS) in agricultural soils by liquid chromatography with fluorescence detection.

    PubMed

    Nimer, M; Ballesteros, O; Navalón, A; Crovetto, G; Verge, C; López, I; Berna, J L; Vílchez, J L

    2007-03-01

    A new sample-treatment procedure has been developed for determination of total linear alkylbenzene sulfonate (LAS), i.e. homologues and isomers, in agricultural soil. The procedure involves two steps, ultrasound-assisted extraction of LAS from the samples with methanol then clean-up of the methanolic extracts and preconcentration of the LAS by solid-phase extraction on two adsorbent cartridges (SAX and C18). The ultrasound-assisted procedure reduces extraction time (10 min in contrast with 6-12 h for conventional Soxhlet extraction) and requires only small volumes of organic solvent. The effect of different variables interacting in the ultrasound-assisted extraction process was studied. Finally, separation and quantification of the homologues and isomers of LAS was performed by liquid chromatography with fluorescence detection (LC-FD). 2-Octylbenzenesulfonic acid sodium salt (Na-2ØC8-LAS) was used as internal standard. The proposed method was satisfactorily used for determination of LAS in agricultural soil samples from the fertile plain of Granada (Spain).

  6. Anaerobic degradation of linear alkylbenzene sulfonate (LAS) in fluidized bed reactor by microbial consortia in different support materials.

    PubMed

    de Oliveira, Lorena Lima; Costa, Rachel Biancalana; Okada, Dagoberto Yukio; Vich, Daniele Vital; Duarte, Iolanda Cristina Silveira; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

    2010-07-01

    Four anaerobic fluidized bed reactors filled with activated carbon (R1), expanded clay (R2), glass beads (R3) and sand (R4) were tested for anaerobic degradation of LAS. All reactors were inoculated with sludge from a UASB reactor treating swine wastewater and were fed with a synthetic substrate supplemented with approximately 20 mg l(-1) of LAS, on average. To 560 mg l(-1) COD influent, the maximum COD and LAS removal efficiencies were mean values of 97+/-2% and 99+/-2%, respectively, to all reactors demonstrating the potential applicability of this reactor configuration for treating LAS. The reactors were kept at 30 degrees C and operated with a hydraulic retention time (HRT) of 18h. The use of glass beads and sand appear attractive because they favor the development of biofilms capable of supporting LAS degradation. Subsequent 16S rRNA gene sequencing and phylogenetic analysis of samples from reactors R3 and R4 revealed that these reactors gave rise to broad microbial diversity, with microorganisms belonging to the phyla Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria, indicating the role of microbial consortia in degrading the surfactant LAS.

  7. A brief hydrologic appraisal of the July 3-4, 1975, flash flood in Las Vegas Valley, Nevada

    USGS Publications Warehouse

    Katzer, T.L.; Glancy, Patrick A.; Harmsen, Lynn

    1976-01-01

    Heavy thunderstorm precipitation on the afternoon of July 3, 1975, between metropolitan Las Vegas and the mountains to the south, west, and north, caused flash flooding in the city area. Total storm precipitation equaled or exceeded 3 inches (76 mm) in some areas. The total storm yield on the area of significant runoff was probably between 20,000 and 25,000 acre-feet (2.5 x 107 m3 and 3.1 x 107 m3) of water. Of this amount, probably less than 3,000 acre-feet (37 x 106 m3) flowed directly to Lake Mead. Peak flows of Tropicana Wash, Flamingo Wash, Las Vegas Creek, and Las Vegas Wash were the highest ever determined. Flooding caused the loss of two lives and inflicted extensive property damage. Total damage was reportedly estimated by the Clark County Flood Control District at $4-5 million. Problems associated with sediment erosion, transportation, and deposition occurred throughout the flooded area. An unknown amount of the material transported during the flood was deposited in Lake Mead near the mouth of Las Vegas Wash. Lateral erosion appeared more prominent than vertical erosion along most major channels, except on Las Vegas Wash at Northshore Road where downcutting threatened the loss of the highway. Sediment deposits were particularly noticeable and troublesome in Flamingo Wash at Caesars Palace parking lot and on the Winterwood Golf Course near the junction of Flamingo Wash and Las Vegas Wash.

  8. The Liege Acromegaly Survey (LAS): a new software tool for the study of acromegaly.

    PubMed

    Petrossians, Patrick; Tichomirowa, Maria A; Stevenaert, Achile; Martin, Didier; Daly, Adrian F; Beckers, Albert

    2012-06-01

    Acromegaly is a chronic rare disease associated with negative pathological effects on multiple systems and organs. We designed a new informatics tool to study data from patients with acromegaly, the Liege Acromegaly Survey (LAS). This relational database permits the inclusion of anonymous historical and prospective data on patients and includes pathophysiology, clinical features, responses to therapy and long term outcomes of acromegaly. We deployed the LAS in a validation study at a single center in order to study the characteristics of patients with acromegaly diagnosed at our center from 1970-2011. A total of 290 patients with acromegaly were included (147 males and 143 females). There was a linear relationship between age at diagnosis and the date of diagnosis, indicating that older patients are being diagnosed with acromegaly more frequently. A majority presented with macroadenomas (77.5%) and the median diameter was 14 mm. Patients with macroadenomas were significantly younger than patients with microadenomas (P=0.01). GH values at diagnosis decreased with the age of the patients (P=0.01) and there was a correlation between GH values and tumor size at diagnosis (P=0.02). No correlation existed between insulin-like growth factor 1 (IGF-1) levels and tumor characteristics. The prevalence of diabetes was 21.4% in this population and 41.0% had hypertension. The presence of hypertension and diabetes were significantly associated with one another (P<0.001). There was a linear relation between initial GH and IGF-1 levels at diagnosis and those obtained during SSA analog treatment and the lowest GH and IGF-1 values following SSA therapy were obtained in older patients (GH: P<0.001; IGF-1: P<0.001). The LAS is a new relational database that is feasible to use in the clinical research setting and permits ready pooling of anonymous patient data from multiple study sites to undertake robust statistical analyses of clinical and therapeutic characteristics.

  9. Elevation Changes of LAS, East Antarctica, Derived From ICESat and CryoSat-2 Altimetric Data

    NASA Astrophysics Data System (ADS)

    Chen, L.; Xie, H.; Hai, G.; Liu, S.; Liu, J.; Tong, X.; Li, R.

    2015-12-01

    Understanding of mass changes of the Antarctic ice sheet is essential for sea level rise study. A research effort has been made to estimate elevation mass changes at Lambert Glacier-Amery Ice Shelf System (LAS), East Antarctica using ICESat data of 2004-2008 and Cryosat-2 data of 2010-2015. A repeat-tack processing method that includes a trend and the first order terrain terms is applied to repeat-track points of all ICESat Campaigns of 2004-2008. The estimated change rate in LAS from 2004-2008 is 3.14±4.13 Gt yr-1. At the basin level, two basins show a combined positive trend of 8.16±2.96 Gt yr-1 while other four basins a combined negative trend of -5.39±6.04 Gt yr-1. Cryosat-2 altimeter works in three modes with the "synthetic aperture interferometer mode" (SARIn) and "low-resolution mode" (LRM) in LAS. Our data coverage is from 2010 to 2015. Cryosat-2 ground tracks do not maintain repeated points. We further divide the entire area into a grid of 5km by 5km. Then we estimate the elevation change rate in each grid cell using a least-squares fitting model with a trend and a second order polynomial. We found that the quality of the estimates is correlated with slopes of cells. The progress of the CryoSat-2 data processing result as well as the analysis with the existing ICESat result will be presented. An integrated model of both ICESat and CryoSat-2 data processing will be developed.

  10. An Aerial Radiological Survey of the Las Vegas Strip and Adjacent Areas

    SciTech Connect

    Wasiolek, Piotr

    2009-02-01

    As proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory–Nellis (RSL-Nellis) conducted an aerial radiological survey of the Las Vegas Strip and adjacent areas on December 29, 2008. This survey was one of the bi-annual surveys carried in support of the city of Las Vegas Police Department (LVPD) before significant events on the Las Vegas Strip: e.g., the annual New Year’s Eve and July Fourth celebrations. The AMS operation and appropriate law enforcement agencies selected this area as an appropriate urban location to exercise AMS capability for mapping environmental radiation and searching for man-made radioactive sources. The surveys covered approximately 11 square miles. Each survey required a 2.5-hour-long flight, performed at an altitude of 300 ft above ground level (AGL) at a line spacing of 600 ft. Water line and test line flights are conducted over the Lake Mead and Government Wash areas to determine the non-terrestrial background contributed by aircraft, radon, and cosmic activity, and to determine the altitude-dependent air mass correction. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2" x 4" x 16" sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Gamma energy spectral data were collected second-by-second over the survey area. This spectral data allows the system to distinguish between natural terrestrial background contributions and man-made radioisotope contributions. Spectral data can also be used to identify specific man-made radioactive isotopes. Data geo-locations were determined with a Real-Time Differential Global Positioning System (RDGPS).

  11. Interferograms showing land subsidence and uplift in Las Vegas Valley, Nevada, 1992-99

    USGS Publications Warehouse

    Pavelko, Michael T.; Hoffmann, Jorn; Damar, Nancy A.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the Nevada Department of Conservation and Natural Resources-Division of Water Resources and the Las Vegas Valley Water District, compiled 44 individual interferograms and 1 stacked interferogram comprising 29 satellite synthetic aperture radar acquisitions of Las Vegas Valley, Nevada, from 1992 to 1999. The interferograms, which depict short-term, seasonal, and long-term trends in land subsidence and uplift, are viewable with an interactive map. The interferograms show that land subsidence and uplift generally occur in localized areas, are responsive to ground-water pumpage and artificial recharge, and, in part, are fault controlled. Information from these interferograms can be used by water and land managers to mitigate land subsidence and associated damage. Land subsidence attributed to ground-water pumpage has been documented in Las Vegas Valley since the 1940s. Damage to roads, buildings, and other engineered structures has been associated with this land subsidence. Land uplift attributed to artificial recharge and reduced pumping has been documented since the 1990s. Measuring these land-surface changes with traditional benchmark and Global Positioning System surveys can be costly and time consuming, and results typically are spatially and temporally sparse. Interferograms are relatively inexpensive and provide temporal and spatial resolutions previously not achievable. The interferograms are viewable with an interactive map. Landsat images from 1993 and 2000 are viewable for frames of reference to locate areas of interest and help determine land use. A stacked interferogram for 1992-99 is viewable to visualize the cumulative vertical displacement for the period represented by the individual interferograms. The interactive map enables users to identify and estimate the magnitude of vertical displacement, visually analyze deformation trends, and view interferograms and Landsat images side by side. The

  12. An Aerial Radiological Survey of the City of North Las Vegas (Downtown) and the Motor Speedway

    SciTech Connect

    Piotr Wasiolek

    2007-12-01

    As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey on December 11-12, 2007, with the purpose of mapping natural radiation background and locating any man-made radioactive sources. The survey covered 19.4 square miles (9.2 square miles over the downtown area of the City of North Las Vegas and 10.2 square miles over the Las Vegas Motor Speedway [LVMS]). The flight lines over the surveyed areas are presented in Figures 1 and 2. A total of four 2.5-hour-long flights were performed at an altitude of 150 ft above ground level (AGL) with 300 ft of flight line spacing. Water line and test line flights were conducted over the Lake Mead and Government Wash areas to ensure quality control of the data. The data were collected by the AMS data acquisition system-REDAR V using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Data in the form of gamma energy spectra were collected continually (every second) over the course of the survey and were geo-referenced using a differential Global Positioning System. Collection of spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man-made radioisotopes sources. Spectral data can also be used to identify specific radioactive isotopes. As a courtesy service with the approval of the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office, RSL-Nellis is providing this summary to the office of the Mayor of City of North Las Vegas and LVMS security along with the gross counts-based exposure rate and man-made counts maps.

  13. Las Cumbres Observatory: Building a global telescope network from the ground up

    NASA Astrophysics Data System (ADS)

    Gomez, E. L.

    2015-03-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) are building a global network of telescopes which will be available to both professional scientists and the science curious public. This telescope network will be global and so will the community, therefore all aspects of the endeavour must be online and self-sustaining - from the observing software to the analysis tools. During 2012 LCOGT have deployed the first 1-meter telescopes, and launched a citizen science project using LCOGT data, Agent Exoplanet, as well as many other online resources for anyone to use as they explore astronomy.

  14. Crystal Structure of the LasA Virulence Factor from Pseudomonas aeruginosa: Substrate Specificity and Mechanism of M23 Metallopeptidases

    SciTech Connect

    Spencer, James; Murphy, Loretta M.; Conners, Rebecca; Sessions, Richard B.; Gamblin, Steven J.

    2010-09-21

    Pseudomonas aeruginosa is an opportunist Gram-negative bacterial pathogen responsible for a wide range of infections in immunocompromized individuals and is a leading cause of mortality in cystic fibrosis patients. A number of secreted virulence factors, including various proteolytic enzymes, contribute to the establishment and maintenance of Pseudomonas infection. One such is LasA, an M23 metallopeptidase related to autolytic glycylglycine endopeptidases such as Staphylococcus aureus lysostaphin and LytM, and to DD-endopeptidases involved in entry of bacteriophage to host bacteria. LasA is implicated in a range of processes related to Pseudomonas virulence, including stimulating ectodomain shedding of the cell surface heparan sulphate proteoglycan syndecan-1 and elastin degradation in connective tissue. Here we present crystal structures of active LasA as a complex with tartrate and in the uncomplexed form. While the overall fold resembles that of the other M23 family members, the LasA active site is less constricted and utilizes a different set of metal ligands. The active site of uncomplexed LasA contains a five-coordinate zinc ion with trigonal bipyramidal geometry and two metal-bound water molecules. Using these structures as a starting point, we propose a model for substrate binding by LasA that explains its activity against a wider range of substrates than those used by related lytic enzymes, and offer a catalytic mechanism for M23 metallopeptidases consistent with available structural and mutagenesis data. Our results highlight how LasA is a structurally distinct member of this endopeptidase family, consistent with its activity against a wider range of substrates and with its multiple roles in Pseudomonas virulence.

  15. Machines, medication, modulation: circuits of dependency and self-care in Las Vegas.

    PubMed

    Schüll, Natasha Dow

    2006-06-01

    The intensive entertainment infrastructure of Las Vegas is overlaid with a robust therapeutic network for those who become addicted to its technologies. Although the objectives of gambling machines and addiction therapeutics are seemingly at odds--the first work to encourage play, the second to stop it--both gear their interventions around a model of the self as a continuum of behavioral potentials that can be externally modulated. For compulsive gamblers implicated in this circuit of modulation, pharmaceutical drugs that have been prescribed to dampen cravings for machine play sometimes function as intensifiers of its effects. Caught in an intractable play between technologies of harm and technologies of care, recovering gambling addicts are challenged to assemble a technical array through which they can maintain balance; health itself, for these individuals, becomes a state of managed dependency. This essay explores the shifting terms and changing stakes of subjectivity and health in the contemporary United States by way of ethnographic research on compulsive gamblers who live and work in Las Vegas. The analysis draws on interviews with gamblers as well as on observations in local self-help groups, directed group therapy sessions, and chat rooms of Internet recovery Web sites.

  16. Excess air during aquifer storage and recovery in an arid basin (Las Vegas Valley, USA)

    NASA Astrophysics Data System (ADS)

    Solomon, D. Kip; Cole, Erin; Leising, Joseph F.

    2011-02-01

    The Las Vegas Valley Water District in Nevada, USA, has operated an artificial recharge (AR) program since 1989. In summer 2001, observations of gas exsolving from tap water prompted a study that revealed total dissolved gas (TDG) pressures approaching 2 atm with a gas composition that it is predominantly air. Measurements of TDG pressure at well heads and in the distribution system indicated two potential mechanisms for elevated TDG pressures: (1) air entrainment during AR operations, and (2) temperature changes between the winter recharge season and the summer withdrawal season. Air entrainment during pumping was investigated by intentionally allowing the forebay (upstream reservoir) of a large pumping station to drawdown to the point of vortex formation. This resulted in up to a 0.7 atm increase in TDG pressure. In general, the solubility of gases in water decreases as the temperature increases. In the Las Vegas Valley, water that acquired a modest amount of dissolved gas during winter artificial recharge operations experienced an increase in dissolved gas pressure (0.04 atm/°C) as the water warmed in the subsurface. A combination of air entrainment during AR operations and its amplification by temperature increase after recharge can account for most of the observed amounts of excess gas at this site.

  17. Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by synthetic aperture radar interferometry

    USGS Publications Warehouse

    Hoffmann, J.; Zebker, H.A.; Galloway, D.L.; Amelung, F.

    2001-01-01

    Analyses of areal variations in the subsidence and rebound occurring over stressed aquifer systems, in conjunction with measurements of the hydraulic head fluctuations causing these displacements, can yield valuable information about the compressibility and storage properties of the aquifer system. Historically, stress-strain relationships have been derived from paired extensometer/piezometer installations, which provide only point source data. Because of the general unavailability of spatially detailed deformation data, areal stress-strain relations and their variability are not commonly considered in constraining conceptual and numerical models of aquifer systems. Interferometric synthetic aperture radar (InSAR) techniques can map ground displacements at a spatial scale of tens of meters over 100 km wide swaths. InSAR has been used previously to characterize larger magnitude, generally permanent aquifer system compaction and land subsidence at yearly and longer timescales, caused by sustained drawdown of ground-water levels that produces intergranular stresses consistently greater than the maximum historical stress. We present InSAR measurements of the typically small-magnitude, generally recoverable deformations of the Las Vegas Valley aquifer system occurring at seasonal timescales. From these we derive estimates of the elastic storage coefficient for the aquifer system at several locations in Las Vegas Valley. These high-resolution measurements offer great potential for future investigations into the mechanics of aquifer systems and the spatial heterogeneity of aquifer system structure and material properties as well as for monitoring ongoing aquifer system compaction and land subsidence.

  18. INTRAVAL Phase 2: Modeling testing at the Las Cruces Trench Site

    SciTech Connect

    Hills, R.G.; Wierenga, P.J.; Luis, S.; McLaughlin, D.; Rockhold, M.; Xiang, J.; Scanlon, B.; Wittmeyer, G.

    1994-01-01

    Several field experiments have been performed by scientists from the University of Arizona and New Mexico State University at the Las Cruces Trench Site to provide data tc test deterministic and stochastic models for water flow and solute transport. These experiments were performed in collaboration with INTRAVAL, an international effort toward validation of geosphere models for the transport of radionuclides. During Phase I of INTRAVAL, qualitative comparisons between experimental data and model predictions were made using contour plots of water contents and solute concentrations. Detailed quantitative comparisons were not made. To provide data for more rigorous model testing, a third Las Cruces Trench experiment was designed by scientists from the University of Arizona and New Mexico State University. Modelers from the Center for Nuclear Waste Regulatory Analysis, Massachusetts Institute of Technology, New Mexico State University, Pacific Northwest Laboratory, and the University of Texas provided predictions of water flow and tritium transport to New Mexico State University for analysis. The corresponding models assumed soil characterizations ranging from uniform to deterministically heterogeneous to stochastic. This report presents detailed quantitative comparisons to field data.

  19. [A new species of the genus Phenylobacterium for the degradation of LAS (linear alkylbenzene sulfonate)].

    PubMed

    Ke, Na; Xiao, Changsong; Ying, Qifeng; Ji, Shulan

    2003-02-01

    A strain GZ6 that can biodegrade LAS (Linear Alkylbenzene Sulphonate) is identified. It is aerobic gram-negative rod or short-rod (0.5 to 0.8 by 1.0 to 2.0 Mm). It is mobile with a single polar flagellum. Optimum growth occurred at 30 degrees C and pH7.0. It is catalase positive, urease positive, and arginine decarboxylase positive. All the other physiological and biochemical tests performed were negative. It utilizes the xenobiotic compounds chloridazon, antipyrin and LAS as sole carbon sources. Most sugars, alcohols, and carboxylic acids are not utilized. It has Q-10 as the major quinone. The main cell fatty acids are Sum7, C16:0 and Sum4. The DNA G + C mol % content is 70.10. A phylogenic tree was constructed on the basis of 16S rDNA sequences. It showed that the previously known member of the genus Phenylobacterium, Phenylobacterium mobile DSM1986T, is the nearest neighbor to strain GZ6. The level of binary sequence similarity between them is 97.49%. And the DNA-DNA relatedness is 40%. These genetic analysis and their morphological difference show that they are different species of Phenylobacterium. A new species, Phenylobacterium mobile sp. nov., has been proposed.

  20. Late quaternary environmental changes in the upper Las Vegas valley, Nevada

    NASA Astrophysics Data System (ADS)

    Quade, Jay

    1986-11-01

    Five stratigraphic units and five soils of late Pleistocene to Holocene age crop out in dissected badlands on Corn Creek Flat, 30 km northwest of Las Vegas, Nevada, and at Tule Springs, nearer to Las Vegas. The record is dominantly fluvial but contains evidence of several moister, marsh-forming periods: the oldest (Unit B) dates perhaps to the middle Wisconsin, and the more widespread Unit D falls between 30,000 and 15,000 yr B.P. Unit D therefore correlates with pluvial maximum lacustrine deposits elsewhere in the Great Basin. Standing water was not of sufficient depth or extent during either period to form lake strandlines. Between 14,000 and 7200 yr B.P. (Unit E), standing surface water gradually decreased, a trend also apparent in Great Basin pluvial lake chronologies during the same period. Groundwater carbonate cementation and burrowing by cicadas (Cicadae) accompany the moist-phase units. After 7200 yr B.P., increased wind action, decreased biotic activity, and at least 25 m of water-table lowering accompanied widespread erosion of older fine-grained deposits. Based on pack-rat midden and pollen evidence, this coincides with major vegetation changes in the valley, from sagebrush-dominated steppe to lower Mohave desertscrub.

  1. On an LAS-integrated soft PLC system based on WorldFIP fieldbus.

    PubMed

    Liang, Geng; Li, Zhijun; Li, Wen; Bai, Yan

    2012-01-01

    Communication efficiency is lowered and real-time performance is not good enough in discrete control based on traditional WorldFIP field intelligent nodes in case that the scale of control in field is large. A soft PLC system based on WorldFIP fieldbus was designed and implemented. Link Activity Scheduler (LAS) was integrated into the system and field intelligent I/O modules acted as networked basic nodes. Discrete control logic was implemented with the LAS-integrated soft PLC system. The proposed system was composed of configuration and supervisory sub-systems and running sub-systems. The configuration and supervisory sub-system was implemented with a personal computer or an industrial personal computer; running subsystems were designed and implemented based on embedded hardware and software systems. Communication and schedule in the running subsystem was implemented with an embedded sub-module; discrete control and system self-diagnosis were implemented with another embedded sub-module. Structure of the proposed system was presented. Methodology for the design of the sub-systems was expounded. Experiments were carried out to evaluate the performance of the proposed system both in discrete and process control by investigating the effect of network data transmission delay induced by the soft PLC in WorldFIP network and CPU workload on resulting control performances. The experimental observations indicated that the proposed system is practically applicable.

  2. Rock magnetic properties and ore microscopy of the iron ore deposit of Las Truchas, Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Urrutia-Fucugauchi, J.

    1998-02-01

    Iron ore and host rocks have been sampled (90 oriented samples from 19 sites) from the Las Truchas mine, western Mexico. A broad range of magnetic parameters have been studied to characterize the samples: saturation magnetization, Curie temperature, density, susceptibility, remanence intensity, Koenigsberger ratio, and hysteresis parameters. Magnetic properties are controlled by variations in titanomagnetite content, deuteric oxidation, and hydrothermal alteration. Las Truchas deposit formed by contact metasomatism in a Mesozoic volcano-sedimentary sequence intruded by a batholith, and titanomagnetites underwent intermediate degrees of deuteric oxidation. Post-mineralization hydrothermal alteration, evidenced by pyrite, epidote, sericite, and kaolin, seems to be the major event that affected the minerals and magnetic properties. Magnetite grain sizes in iron ores range from 5 to >200 μm, which suggest dominance of multidomain (MD) states. Curie temperatures are 580±5°C, characteristic of magnetite. Hysteresis parameters indicate that most samples have MD magnetite, some samples pseudo-single domain (PSD), and just a few single domain (SD) particles. AF demagnetization and IRM acquisition indicate that NRM and laboratory remanences are carried by MD magnetite in iron ores and PSD-SD magnetite in host rocks. The Koenigsberger ratio falls in a narrow range between 0.1 and 10, indicating the significance of MD and PSD magnetites.

  3. Ground-water conditions in Las Veags Valley, Clark County, Nevada; part 1 Hydrogeologic Framework

    USGS Publications Warehouse

    Plume, Russell W.

    1989-01-01

    This report describes the lithology, thickness, and extent of valley-fill deposits in Las Vegas Valley, Nev. This information will be used to develop a hydraulic model of the valley's ground-water system. Las Vegas Valley is a structural basin formed by bedrock that ranges in age from Precambrian through Miocene. Gravity data indicate that the deeper parts of the basin are filled with 3,000-5,000 feet of clastic sedimentary deposits that range in age from Miocene through Holocene. These deposits constitute the valley-fill aquifer and yield most of the water pumped in the valley. The upper 1,000 feet of this valley fill consist of coarse-grained deposits (sand and gravel), fine-grained deposits (silt and clay), and heterogeneous deposits that comprise either thinly interbedded coarse- and fine-grained deposits or mixtures of the two. Coarse-grained deposits, in places more than 1,000 feet thick, underlie the south and west sides of the valley and interfinger with fine-grained and heterogeneous deposits toward the center of the valley. Intervals of fairly thin heterogeneous deposits underlie parts of the valley, but they are not laterally persistent. The distribution of coarse-grained and fine-grained deposits in three depth zones of the valley fill (0-200 feet, 200-700 feet, and 700-1,000 feet) suggests that: (1) the Spring Mountains and McCullough Range were the major sources of clastic material for the valley fill; (2) Frenchman Mountain and the Las Vegas Range were emplaced later than the Spring Mountains; (3) the east side of the Spring Mountains, which was originally closer to the center of the valley, has receded westward because of erosion; and (4) shallow, fine-grained deposits (0-200 feet deep) are more susceptible to subsidence than deeper ones. The bedrock basin that underlies Las Vegas Valley consists of a deeply buried part that underlies most of the valley and a shallow bedrock surface on the west side of the valley. The deep part of the basin is

  4. MBAS (Methylene Blue Active Substances) and LAS (Linear Alkylbenzene Sulphonates) in Mediterranean coastal aerosols: Sources and transport processes

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Ghedini, C.; Peeters, S.; Rottiers, A.; Traversi, R.; Udisti, R.; Chiari, M.; Jalba, A.; Despiau, S.; Dayan, U.; Temara, A.

    2011-12-01

    Methylene Blue Active Substances (MBAS) and Linear Alkylbenzene Sulphonates (LAS) concentrations, together with organic carbon and ions were measured in atmospheric coastal aerosols in the NW Mediterranean Basin. Previous studies have suggested that the presence of surfactants in coastal aerosols may result in vegetation damage without specifically detecting or quantifying these surfactants. Coastal aerosols were collected at a remote site (Porquerolles Island-Var, France) and at a more anthropised site (San Rossore National Park-Tuscany, Italy). The chemical data were interpreted according to a comprehensive local meteorological analysis aiming to decipher the airborne source and transport processes of these classes of compounds. The LAS concentration (anthropogenic surfactants) was measured in the samples using LC-MS/MS, a specific analytical method. The values were compared with the MBAS concentration, determined by a non-specific analytical method. At Porquerolles, the MBAS concentration (103 ± 93 ng m -3) in the summer samples was significantly higher than in the winter samples. In contrast, LAS concentrations were rarely greater than in the blank filters. At San Rossore, the mean annual MBAS concentration (887 ± 473 ng m -3 in PM10) contributed about 10% to the total atmospheric particulate organic matter. LAS mean concentration in these same aerosol samples was 11.5 ± 10.5 ng m -3. A similar MBAS (529 ± 454 ng m -3) - LAS (7.1 ± 4.1 ng m -3 LAS) ratio of ˜75 was measured in the fine (PM2.5) aerosol fraction. No linear correlation was found between MBAS and LAS concentrations. At San Rossore site the variation of LAS concentrations was studied on a daily basis over a year. The LAS concentrations in the coarse fraction (PM10-2.5) were higher during strong sea storm conditions, characterized by strong air flow coming from the sea sector. These events, occurring with more intensity in winter, promoted the formation of primary marine aerosols containing LAS

  5. The degradation of linear alkylbenzene sulfonate (LAS) in the presence of light and natural biofilms: the important role of photosynthesis.

    PubMed

    Hua, Xiuyi; Li, Ming; Su, Yulong; Dong, Deming; Guo, Zhiyong; Liang, Dapeng

    2012-08-30

    Photosynthesis of algae usually changes the chemical conditions of microenvironment in natural waters. However, few studies have been carried out to examine the effects of diurnal variation and photosynthesis on behavior of organic pollutants in aquatic environments. In this study, linear alkylbenzene sulfonate (LAS) was selected as a representative of non-persistent organic pollutants to investigate the degradation of this type of pollutants in the presence of light and natural biofilms by laboratory batch experiments, with special emphasis on the effect of photosynthesis of the biofilms. The maximum decrease of LAS was observed in the coexistence of both illumination and fully active biofilms, and about 75% of the LAS were removed after a 36-h degradation experiment. The removal of LAS was found to be dominated by photosynthesis of the biofilms, with lesser roles attributed to biodegradation and adsorption by the biofilms, and the role of direct photolysis was negligible. The production of some reactive oxygen species might account for the role of photosynthesis in decomposing the LAS. The study confirms the important roles of algae biofilms and their photosynthesis in determining the fate of organic pollutants in aquatic environments.

  6. Wide-range and accurate modeling of linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil.

    PubMed

    Oliver-Rodríguez, B; Zafra-Gómez, A; Reis, M S; Duarte, B P M; Verge, C; de Ferrer, J A; Pérez-Pascual, M; Vílchez, J L

    2015-11-01

    In this paper, rigorous data and adequate models about linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil are presented, contributing with a substantial improvement over available adsorption works. The kinetics of the adsorption/desorption phenomenon and the adsorption/desorption equilibrium isotherms were determined through batch studies for total LAS amount and also for each homologue series: C10, C11, C12 and C13. The proposed multiple pseudo-first order kinetic model provides the best fit to the kinetic data, indicating the presence of two adsorption/desorption processes in the general phenomenon. Equilibrium adsorption and desorption data have been properly fitted by a model consisting of a Langmuir plus quadratic term, which provides a good integrated description of the experimental data over a wide range of concentrations. At low concentrations, the Langmuir term explains the adsorption of LAS on soil sites which are highly selective of the n-alkyl groups and cover a very small fraction of the soil surface area, whereas the quadratic term describes adsorption on the much larger part of the soil surface and on LAS retained at moderate to high concentrations. Since adsorption/desorption phenomenon plays a major role in the LAS behavior in soils, relevant conclusions can be drawn from the obtained results.

  7. Overexpression of the Brassica napus BnLAS gene in Arabidopsis affects plant development and increases drought tolerance.

    PubMed

    Yang, Minggui; Yang, Qingyong; Fu, Tingdong; Zhou, Yongming

    2011-03-01

    The GRAS proteins are a family of transcription regulators found in plants and play diverse roles in plant growth and development. To study the biological roles of GRAS family genes in Brassica napus, an Arabidopsis LAS homologous gene, BnLAS and its two homologs were cloned from B. napus and its two progenitor species, Brassica rapa and Brassica oleracea. Relatively high levels of BnLAS were observed in roots, shoot tips, lateral meristems and flower organs based on the analysis of the transcripts by quantitative RT-PCR and promoter-reporter assays. Constitutive overexpression of BnLAS in Arabidopsis resulted in inhibition of growth, and delays in leaf senescence and flowering time. A large portion of transgenic lines had darker leaf color and higher chlorophyll content than in wild type plants. Interestingly, water lose rates in transgenic leaves were reduced, and transgenic plants exhibited enhanced drought tolerance and increased recovery after exposed to dehydration treatment. The stomatal density on leaves of the transgenic plants increased significantly due to the smaller cell size. However, the stomatal aperture on the leaves of the transgenic plants reduced significantly compared with wild type plants. More epidermal wax deposition on transgenic leaves was observed. Furthermore, several genes involved in wax synthesis and regulation, including CER1, CER2, KCS1 and KCS2, were upregulated in the transgenic plants. Our results indicate a potential to utilize BnLAS in the improvement of drought tolerance in plants.

  8. The study of ozone variations in the Las Vegas metropolitan area using remote sensing information and ground observations

    USGS Publications Warehouse

    Xian, G.; Crane, M.

    2006-01-01

    Urban development in the Las Vegas Valley, Nevada, has grown rapidly in the past fifty years. Associated with this growth has been a change in landscape from natural cover types to developed urban land mixed with planned vegetation canopy throughout in the metropolitan area. Air quality in the Las Vegas Valley has been affected by increases in anthropogenic emissions and concentrations of carbon monoxide, ozone, and criteria pollutants of particular matter. Ozone concentration in the region is generally influenced by synoptic and mesoscale meteorological conditions, as well as regional transport of pollutants from the western side of Las Vegas. Local influences from ground-level nitrogen oxide emissions and vegetation canopy coverage also affect ozone concentration. Multi-year observational data collected by a network of local air monitoring stations in Clark County, Nevada, indicate that ozone maximums develop in May and June, while minimums exist primarily from November to February. Ozone concentrations are high on the west and northwest sides of the valley. A nighttime ozone reduction in the urban area characterizes the heterogeneous features of spatial distribution for average ozone levels in the Las Vegas urban area. The urban vegetation canopy has a locally positive effect by reducing ozone in urban areas. Decreased ozone levels associated with increased urban development density suggests that the highest ozone concentrations are associated with medium- to low-density urban development in Las Vegas.

  9. Shallow Shear Velocity and Seismic Microzonation of the Las Vegas Urban Basin

    NASA Astrophysics Data System (ADS)

    Rasmussen, T.; Smith, S. B.; Clark, M.; Lopez, C.; Loughner, C.; Park, H.; Scott, J. B.; Thelen, W.; Greschke, B.; Louie, J. N.

    2003-12-01

    In July 2003 we performed a seismic microzonation study of the Las Vegas basin along a 15 kilometer transect. Using 120 Reftek RT-125 "Texans" on loan from PASSCAL, we completed this transect in two days. 4.5-Hz geophones collected Rayleigh-wave data for dispersion analysis and velocity-profile modeling. Only passive urban seismic noise sources are needed for this refraction microtremor analysis; freeway and commuter traffic are used in this case. Using a geophone spacing of 20 meters, fifty 260-m array sections were analyzed to create a transect of 30-m shear velocity measurements 15 km long. The transect runs approximately parallel to Interstate 15 from Cheyenne Avenue at the north to Tropicana Avenue at the south, passing most of The Strip and downtown Las Vegas. We added a few refraction lines, with a sledgehammer source, to augment the microtremor dispersion data with P velocities. The lowest shear velocities observed in Las Vegas are in the NEHRP class D range, at 230 m/s, well above the NEHRP class E range. These lower velocities are found near Interstate 15 and Lake Mead Blvd. Velocities then rise smoothly southward to the middle of the NEHRP-C range (450-600 m/s) near Sahara Blvd. to the south. There appears to be a slight decline further south to Tropicana Blvd. Our results from only 3 km out of the 15-km-long transect have velocities near or below the NEHRP-C/D boundary at 350 m/s. This survey suggests a medium-scale study with a limited budget can be completed in a short time. The study is a crucial new step in the characterization of the effects of ground shaking due to a seismic source in the surrounding region. Similar studies have been completed in the Reno area basin and in the Los Angeles Basin. All of these studies suggest that shallow shear velocity does not correlate well with geologic map units. The range of velocities within one map unit is greater than the average difference between units.

  10. Sociohydrology of an Arid City: Development of a Coupled Model of Water Management in Las Vegas

    NASA Astrophysics Data System (ADS)

    Garcia, M. E.; Islam, S.; Portney, K. E.

    2014-12-01

    Rapidly growing cities in arid regions present a significant water management challenge. Key to tackling this challenge is understanding how and why some cities transition to more sustainable water management; acknowledging that urban water resources decisions are both responding to and precipitating hydrologic change, this question is best tackled through a sociohydrology approach. While coupling of natural and societal systems is in it's infancy in the field of hydrology, there is a strong tradition of studying coupled systems in the field of Socio-Ecological Systems. We build on Ostrom's Socio-Ecological Systems framework to develop a system dynamics model of water management for the Las Vegas metropolitan area using Vensim. A key objective our proposed modeling framework is to illuminate the dynamic interactions of the sociohydrologic system components and enable testing of various assumptions and strategies. The model of Las Vegas water management consists of five sub-modules: water supply, water demand, finances, public perception and policy making process. The development of the first three modules were based on clearly defined system structure. The public perception sub-module tracks the level public risk perception of a water supply shortage and represents the hypothesis that public risk perception is updated periodically when shortage events are experienced. The policy making process module uses an algorithm capturing the hypothesized decision making process to select policy actions (or in-action) from a set of feasible actions in response to the system states tracked by the model and observable to decision makers. The model was tested and parameterized using mix of quantitative data on water demands, supplies and costs and qualitative data from document analysis and interview data covering 1990 to 2010 period. Given that not only the parameters but also the structure of the public perception and the policy making process sub-systems is contested, a

  11. Geodetic Constraints on Fault Slip Rates and Seismic Hazard in the Greater Las Vegas Area

    NASA Astrophysics Data System (ADS)

    Hammond, W. C.; Kreemer, C.; Blewitt, G.; Broermann, J.; Bennett, R. A.

    2014-12-01

    We address fundamental questions about how contemporary tectonic deformation of the crust in the southern Great Basin occurs in the region around Las Vegas (LV) Nevada, western Arizona and eastern California. This area lies in the intersection of the eastern Walker Lane Belt, southern Great Basin and western Colorado Plateau (CP), sharing features of transtensional and extensional deformation associated with Pacific/North America relative motion. We use GPS data collected from 48 stations of the MAGNET semi-continuous network and 77 stations from continuous networks including BARGEN and EarthScope Plate Boundary Observatory. MAGNET stations have been observed for a minimum of 7 years, while most continuous stations have longer records. From these data we estimate the velocity of crustal motion for all stations with respect to the stable North America reference frame NA12. To correct for transients from recent large earthquakes including the 1999 Hector Mine and 2010 El Mayor-Cucapah events we use models of co- and post-seismic deformation, subtracting the predicted motions from the time series before estimating interseismic stain rates. We find approximately 2 mm/yr of relative motion distributed over 200 km centered on Las Vegas, with a mean strain accumulation rate of 10 × 10-9 yr-1, with lower rates of predominantly extensional strain to the east and higher rates of predominantly shear deformation to the west. The mean strain rate is lower than that of the western Walker Lane but about twice that of eastern Nevada where e.g., the Wells, NV MW 6.0 earthquake occurred in 2008. From this new velocity field we generated a horizontal tensor strain rate map and a crustal block motion model to portray the transition of active strain from the CP into the Walker Lane. For faults in the Las Vegas Valley, including the Eglington Fault and Frenchman Mountain Fault, the observed velocity gradients and model results are consistent with normal slip rates of 0.2 mm/yr, which

  12. 20 years of mass balances on the Piloto glacier, Las Cuevas river basin, Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Leiva, J. C.; Cabrera, G. A.; Lenzano, L. E.

    2007-10-01

    Climatic changes of the 20th century have altered the water cycle in the Andean basins of central Argentina. The most visible change is seen in the mountain glaciers, with loss of part of their mass due to decreasing thickness and a substantial recession in the last 100 years. This paper briefly describes the results of glacier mass balance research since 1979 in the Piloto Glacier at the Cajón del Rubio, in the headwaters of Las Cuevas River, presenting new results for the period 1997-2003. Very large interannual variability of net annual specific balance is evident, due largely to variations in winter snow accumulation, with a maximum net annual value of + 151 cm w.e. and a minimum value of - 230 cm w.e. Wet El Niño years are normally associated with positive net annual balances, while dry La Niña years generally result in negative balances. Within the 24-year period, 67% of the years show negative net annual specific balances, with a cumulative mass balance loss of - 10.50 m water equivalent (w.e.). Except for exceptions normally related to El Niño events, a general decreasing trend of winter snow accumulation is evident in the record, particularly after 1992, which has a strong effect in the overall negative mass balance values. The glacier contribution to Las Cuevas River runoff is analysed based on the Punta de Vacas River gauge station for a hypothetical year without snow precipitation (YWSP), when the snowmelt component is zero. Extremely dry years similar to a YWSP have occurred in 1968-1969, 1969-1970 and 1996-1997. The Punta de Vacas gauge station is located 62 km downstream from Piloto Glacier, and the basin contains 3.0% of uncovered glacier ice and 3.7% of debris-covered ice. The total glacier contribution to Las Cuevas River discharge is calculated as 82 ± 8% during extremely dry years. If glacier wastage continues at the present trend as observed during the last 2 decades, it will severely affect the water resources in the arid central Andes of

  13. [Cognitive assessment in children who presented gastroschisis: a case-control study].

    PubMed

    Villasenor-Cabrera, Teresita; Pacheco-Sanchez, Ilude; Rizo-Curiel, Genoveva; Nuno-Romero, Ricardo; Garcia-Estrada, Joaquín

    2016-04-16

    Introduccion. La gastrosquisis es una malformacion de la pared abdominal que se corrige mediante cirugia y requiere cuidados hospitalarios especiales, como inmovilizacion, restriccion alimenticia y separacion de la madre durante tiempo variable, entre otros; para analizar las posibles repercusiones cognitivas se aplico la prueba de Bayley III a 14 niños. Sujetos y metodos. Siete casos (nacidos con gastrosquisis) y siete controles, en los hospitales civiles de Guadalajara, en el periodo enero-abril de 2013. Resultados. Los casos no evidenciaron retraso en las evaluaciones relacionadas con la cognicion, el lenguaje y la conducta motora, en tanto que en las asociadas a la conducta socioemocional y adaptativa las puntuaciones favorecieron al grupo control, lo que refleja que poseen mejores estrategias de adaptacion e interaccion respecto al grupo de casos. Conclusiones. La gastrosquisis no afectara el neurodesarrollo ulterior, por lo menos en este grupo que presento esta unica anormalidad y deficits explicables por sus circunstancias perinatales, sin que este pronostico pueda generalizarse a otros casos con un cuadro clinico mas grave, mayor duracion de la estancia hospitalaria y comorbilidad asociada. De cualquier forma, es importante informar a los padres desde la etapa prenatal respecto a las consecuencias esperadas de esta patologia.

  14. A design for a new catalog manager and associated file management for the Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Greenhagen, Cheryl

    1986-01-01

    Due to the larger number of different types of files used in an image processing system, a mechanism for file management beyond the bounds of typical operating systems is necessary. The Transportable Applications Executive (TAE) Catalog Manager was written to meet this need. Land Analysis System (LAS) users at the EROS Data Center (EDC) encountered some problems in using the TAE catalog manager, including catalog corruption, networking difficulties, and lack of a reliable tape storage and retrieval capability. These problems, coupled with the complexity of the TAE catalog manager, led to the decision to design a new file management system for LAS, tailored to the needs of the EDC user community. This design effort, which addressed catalog management, label services, associated data management, and enhancements to LAS applications, is described. The new file management design will provide many benefits including improved system integration, increased flexibility, enhanced reliability, enhanced portability, improved performance, and improved maintainability.

  15. 3D inversion of aeromagnetic Data on Las Tablas District, Panama

    NASA Astrophysics Data System (ADS)

    Batista-Rodríguez, José A.; Caballero, Alberto; Pérez-Flores, Marco A.; Almaguer-Carmenates, Yuri

    2017-03-01

    We present a 3D model of Las Tablas District, Panama, obtained from the 3D inversion of aeromagnetic data, and constrained with information from surface geology, water wells and topography. The 3D model suggests the location, boundary, shape and depths of the sedimentary basin where the Mensabé and Salados rivers hydrogeological sub-basin is located. The model shows the connections between tectonics and the sedimentary basin, suggesting the probable areas for aquifers, the relations between them, their zone of recharge and discharge, and the probable zone of pollution. The inferred faults in the model may be the main recharge and discharge conduits for the groundwater and anthropogenic pollution. The geological and geometric characteristics shown in the 3D model are fundamental data for further hydrogeological and geophysical studies such as the location for future drinking water wells.

  16. Neighborhood Reputation and Resident Sentiment in the Wake of the Las Vegas Foreclosure Crisis.

    PubMed

    Pais, Jeremy; Batson, Christie D; Monnat, Shannon M

    2014-09-01

    This study examines how two major components of a neighborhood's reputation-perceived disorder and collective efficacy-shape individuals' sentiments toward their neighborhoods during the foreclosure crisis triggered by the Great Recession. Of central interest are whether neighborhood reputations are durable in the face of a crisis (neighborhood resiliency hypothesis) or whether neighborhood reputations wane during times of duress (foreclosure crisis hypothesis). Geo-coded individual-level data from the Las Vegas Metropolitan Area Social Survey merged with data on census tract foreclosure rates are used to address this question. The results provide qualified support for both perspectives. In support of the neighborhood resiliency hypothesis, collective efficacy is positively associated with how residents feel about the quality of their neighborhoods, and this relationship is unaltered by foreclosure rates. In support of the foreclosure crisis hypothesis, foreclosure rates mediate the effects of neighborhood disorder on resident sentiment. The implications of these findings for community resiliency are discussed.

  17. The Proteus aircraft and NASA Dryden's T-34 in flight over Las Cruces, New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  18. The Palomar-Las Campanas Observatory-NOAO (PLCON) Open Cluster Survey

    NASA Astrophysics Data System (ADS)

    Phelps, R. L.; Tollefson, J.; Reafsnyder, S.; Frinchaboy, P.; Craig, Aidan; Postlethwaite, J.; Marshall, T.

    2000-12-01

    The Palomar-Las Campanas Observatory-NOAO (PLCON) Open Cluster Survey is a long-term survey intended to provide CCD derived, VI color-magnitude diagrams for the majority of the Milky Way's open clusters, most of which have been poorly studied in the past, or never studied at all. From these data, systematic estimates of cluster reddenings, distances and ages can be derived using a limited number of telescopes, CCDs and filter sets. These data will be useful for systematic studies of Galactic structure in the disk, the properties of unique/interesting stars within clusters, stellar evolution theory, and a host of other timely astrophysical questions. This paper will report on recent results from the Survey. This work is supported, in part, by grants from the National Science Foundation and the California State University, Sacramento Research and Creative Activity Awards Program.

  19. Prevalence of ectoparasitic arthropods on wild animals and cattle in the Las Merindades area (Burgos, Spain)

    PubMed Central

    Domínguez-Peñafiel, G.; Giménez-Pardo, C.; Gegúndez, M.I.; Lledó, L.

    2011-01-01

    This paper reports the prevalence of ectoparasitic arthropods in sampled groups of wild (n = 128; 16 species) and domestic (n = 69; 3 species) animals in the Las Merindades area of the Province of Burgos, Spain. The study revealed that wild animals were more infested and with a wider variety of ectoparasites than domestic animals. The parasitic prevalence was 67% for wild animals and 48% for livestock. In this way, 39% of animals were infected by ticks. Ixodes ricinus and Ixodes hexagonus were the most prevalent species whereas Dermacentor reticulatus showed affinity for the fox and wolf. The overall prevalence of parasitisation by fleas was 27%. Ctenophthalmus spp. showed the wider range host in wild animals, while Pulex irritans was the most frequent specie found. The parasitic prevalences by lice (Trichodectes melis, Trichodectes canis and Trichodectes mustelae) and by mite (Neotrombicula spp., Laelaps agilis and Sarcoptes scabiei) were 4% and 12%, respectively. In both cases only wild animals were found parasited. PMID:21894267

  20. Neighborhood Reputation and Resident Sentiment in the Wake of the Las Vegas Foreclosure Crisis

    PubMed Central

    Pais, Jeremy; Batson, Christie D.; Monnat, Shannon M.

    2014-01-01

    This study examines how two major components of a neighborhood’s reputation—perceived disorder and collective efficacy—shape individuals’ sentiments toward their neighborhoods during the foreclosure crisis triggered by the Great Recession. Of central interest are whether neighborhood reputations are durable in the face of a crisis (neighborhood resiliency hypothesis) or whether neighborhood reputations wane during times of duress (foreclosure crisis hypothesis). Geo-coded individual-level data from the Las Vegas Metropolitan Area Social Survey merged with data on census tract foreclosure rates are used to address this question. The results provide qualified support for both perspectives. In support of the neighborhood resiliency hypothesis, collective efficacy is positively associated with how residents feel about the quality of their neighborhoods, and this relationship is unaltered by foreclosure rates. In support of the foreclosure crisis hypothesis, foreclosure rates mediate the effects of neighborhood disorder on resident sentiment. The implications of these findings for community resiliency are discussed. PMID:25678735

  1. Late Neandertals in Southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain

    PubMed Central

    Walker, Michael J.; Gibert, Josep; López, Mariano V.; Lombardi, A. Vincent; Pérez-Pérez, Alejandro; Zapata, Josefina; Ortega, Jon; Higham, Thomas; Pike, Alistair; Schwenninger, Jean-Luc; Zilhão, João; Trinkaus, Erik

    2008-01-01

    Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to ≤43,000–40,000 calendar years before present) present a suite of derived Neandertal and/or retained ancestral morphological features in the mandibular symphysis, mandibular ramus, dental occlusal morphology, and distal hand phalanx. These traits are combined with variation in the mandibular corpus, discrete dental morphology, tooth root lengths, and anterior dental size that indicate a frequency difference with earlier Iberian and more northern European Neandertals. The Palomas Neandertals therefore confirm the late presence of Neandertals associated with the Iberian persistence of the Middle Paleolithic, but suggest microevolutionary processes and/or population contact with contemporaneous modern humans to the north. PMID:19074275

  2. Neandertal postcranial remains from the Sima de las Palomas del Cabezo Gordo, Murcia, southeastern Spain.

    PubMed

    Walker, Michael J; Ortega, Jon; López, Mariano V; Parmová, Klára; Trinkaus, Erik

    2011-04-01

    The Sima de las Palomas, southeastern Spain, has yielded a series of Neandertal postcranial remains, including immature and mature isolated elements and the fragmentary partial skeleton of a young adult (Palomas 92). The remains largely conform to the general late archaic/Neandertal morphological pattern in terms of humeral diaphyseal shape, pectoralis major tuberosity size and pillar thickness, ulnar coronoid process height, manual middle phalangeal epiphyseal breadth, manual distal phalangeal tuberosity shape and breadth, femoral diaphyseal shape, and probably body proportions. Palomas 92 contrasts with the Neandertals in having variably gracile hand remains, a more sellar trapezial metacarpal 1 facet, more anteroposteriorly expanded mid-proximal femoral diaphysis, and less robust pedal proximal phalanges. The Palomas Neandertals contrast with more northern European Neandertals particularly in various reflections of overall body size.

  3. Late neandertals in southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain.

    PubMed

    Walker, Michael J; Gibert, Josep; López, Mariano V; Lombardi, A Vincent; Pérez-Pérez, Alejandro; Zapata, Josefina; Ortega, Jon; Higham, Thomas; Pike, Alistair; Schwenninger, Jean-Luc; Zilhão, João; Trinkaus, Erik

    2008-12-30

    Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to

  4. Spatial distribution and contamination assessment of heavy metals in urban topsoils from Las Tunas City, Cuba.

    PubMed

    Díaz Rizo, O; Fonticiella Morell, D; Arado López, J O; Borrell Muñoz, J L; D'Alessandro Rodríguez, K; López Pino, N

    2013-07-01

    Concentrations of Cr, Co, Ni, Cu, Zn, Pb and Fe in the topsoils (0-10 cm) from Las Tunas city were measured by X-ray fluorescence analysis. The mean Cr, Co, Ni, Cu, Zn and Pb contents in the urban topsoil samples (97 ± 30, 14 ± 2, 35 ± 36, 94 ± 26, 199 ± 87 and 42 ± 29 mg kg⁻¹ dry weight, respectively) were compared with mean concentrations for other cities around the world with similar population. Cr content in school grounds, parks and residential areas exceed in 20 % the average Cr background level. Highest content for Ni was determined in residential areas, for Zn in market gardens soils and as for Pb, the highest topsoil-background content ratios were observed for market gardens (2.7) and residential areas (2.3). Spatial distribution maps indicated the same behaviour for Cr-Co-Ni and Pb-Zn, respectively, whereas the spatial distribution of Cu differs from other heavy metals. On the other hand, the metal-to-iron normalisation, using (10-20 cm) bottom soil contents as background, showed that topsoils in Las Tunas city are severely enriched with lead and not enriched with the rest of the determined metals. The average values of integrated pollution index (IPI) indicated that soils are moderately contaminated by heavy metals (1.17 ≤ IPI(ave) ≤ 1.39), but enrichment index values shows that metal concentrations on the studied locations are not above the permissible levels for urban agriculture.

  5. Fishery of the Green Jack Caranx caballus (Osteichytes: Carangidae) in Las Perlas Archipelago, Pacific Panama.

    PubMed

    Mair, James M; Cipriani, Roberto; Guzman, Hector M; Usan, David

    2012-09-01

    Green Jacks, Caranx caballus, are distributed along the Eastern Pacific coast. In Panama, C. caballus was heavily fished around Las Perlas Archipelago to sustain local markets until 2007, when the archipelago was declared a marine protected area. This first study in Panama, analyzed a sample of 4 990 individuals from Las Perlas, obtained monthly from June 2005 to June 2006, from landings at the central fish market. Average total length was 36.1 +/- 6.4cm and optimum length 38.9cm. Approximately 68% of fish lengths were within +/-10% of the optimal length but only six (15%) were considered mega-spawners. The von Bertalanffy parameters describe a long-lived and fast growing species, while mortality rates revealed that C. caballus is under high fishing pressure. Standard length at which half of the population is mature was 38.8cm, and the size at which individuals matured massively, 33cm. Only 10-13% of the fish were immature. C. caballus reproduces two to three times per year, with peaks in December, April, and probably September, and recruits to the population at least twice per year. Catch per unit effort (CPUE) was best predicted by minimum annual values of the Multivariate ENSO/LNSO Index (MEI) (R2=0.54). Results show that C. caballus in Pacific Panama is overfished. We recommend the raising of the minimum capture/landing size of this species in order to increase the proportion of mega-spawners in the population and guarantee the sustainability of this resource.

  6. Regiones de formación de estrellas masivas en las Nubes de Magallanes

    NASA Astrophysics Data System (ADS)

    Barbá, R.; Maíz Apellániz, J.; Rubio, M.; Walborn, N.

    Las Nubes de Magallanes son un laboratorio formidable para el estudio de regiones de formación estelar. A diferencia de lo que sucede en el plano galáctico, ambas galaxias contienen poco polvo que nos afecte la visión directa de dichas regiones. Por otra parte, la menor metalicidad de las Nubes, nos permiten hacer un estudio comparativo de la formación estelar en ambientes de baja metalicidad. El presente trabajo da una revisión de los progresos notables que hemos alcanzado en el conocimiento del contenido estelar de algunas regiones de formación de estrellas masivas en ambas Nubes, en base a la utilización de imágenes del Telescopio Espacial Hubble, Gemini Sur, y Very Large Telescope, entre otros. En especial, nos concentramos en 30 Doradus y N11 en la Nube Mayor, y en NGC 346 en la Nube Menor. Nuevas imágenes de N11 obtenidas en los últimos meses con la Advanced Camera for Surveys del Hubble (óptico), y con Flamingos en Gemini Sur (infrarrojo), nos han permitido descubrir un nuevo `jet' con origen en una fuente infrarroja sumergida en un pilar polvoriento similar al objeto Herbig-Haro de M20 en nuestra galaxia. Este `jet' (junto a otros tres que hemos descubierto en 30 Doradus), es el cuarto ejemplo confirmado de `jet' asociado a una protoestrella fuera de nuestra galaxia. Además, presentamos el descubrimiento del primer objeto estelar joven masivo de la Nube Menor confirmado espectroscópicamente.

  7. Precisión de las velocidades radiales obtenidas con el REOSC

    NASA Astrophysics Data System (ADS)

    González, J. F.; Lapasset, E.

    Complementando una línea de trabajo iniciada con anterioridad discutimos la estabilidad del espectrógrafo REOSC de CASLEO en DC para la medición de velocidades radiales en base al análisis de observaciones realizadas en enero y abril de 1997. En esas oportunidades obtuvimos 26 espectros de estrellas patrones y 27 espectros de 3 estrellas usadas como estrellas de referencia en nuestro programa de cúmulos abiertos. Además tomamos 26 espectros de crepúsculo con el telescopio en posiciones cubriendo el rango H=-4,+4 y δ =-90,+30. Mediante correlaciones cruzadas derivamos la velocidad de 19 órdenes en cada uno de estos espectros. En base a un análisis estadístico de los datos obtenidos discutimos la contribución de los distintos factores que afectan a la dispersión de lectura observada. En particular, la flexión del instrumento no introduciría errores significativos cuando se observa con masas de aire menores que 2.0. La dispersión de los valores de velocidad medidos para espectros de alta relación S/N de una misma estrella resultó del orden de 0.5 km/s. La comparación con los valores de velocidad publicados por distintos autores para las estrellas patrones no permite distinguir ninguna diferencia sistemática apreciable de las velocidades de CASLEO, siendo la media cuadrática de los residuos del orden de 1.0 km/s.

  8. Stratospheric contribution to surface ozone in the desert Southwest during the 2013 Las Vegas Ozone Study

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II; Brioude, J. F.; Cooper, O. R.; Holloway, J. S.; Lin, M.; Marchbanks, R.; Pierce, R. B.; Reddy, P. J.; Sandberg, S.; Weickmann, A. M.; Williams, E. J.; Gustin, M. S.; Iraci, L. T.; Leblanc, T.; Yates, E. L.

    2014-12-01

    The 2013 Las Vegas Ozone Study (LVOS) was designed to investigate the potential impact of stratosphere-troposphere transport (STT) and long-range transport of pollution from Asia on surface O3 concentrations in Clark County, NV. This measurement campaign, which took place in May and June of 2013, was conducted at Angel Peak, NV, a high elevation site about 2.8 km above mean sea level and 45 km west of Las Vegas. The study was organized around the NOAA ESRL truck-based TOPAZ scanning ozone lidar with collocated in situ sampling of O3, CO, and meteorological parameters. These measurements were supported by the NOAA/NESDIS real time modelling system (RAQMS), FLEXPART particle dispersion model, and the NOAA GFDL AM3 model. In this talk, I will describe one of several STT events that occurred during the LVOS campaign. This intrusion, which was profiled by TOPAZ on the night of May 24-25, was also sampled by the NASA Alpha Jet, the Table Mountain ozone lidar, and by an ozonesonde flying above southern California. This event also led to significant ozone increases at surface monitors operated by Clark County, the California Air Resources Board, the U.S. National Park Service, and the Nevada Rural Ozone Initiative (NRVOI), and resulted in exceedances of the 2008 75 ppbv O3 NAAQS both in Clark County and in surrounding areas of Nevada and southern California. The potential implications of this and similar events for air quality compliance in the western U.S. will be discussed.

  9. Characterization of stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, 1998-99

    USGS Publications Warehouse

    Rodriguez, Jose M.

    2000-01-01

    Stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, were characterized from June 1998 to July 1999 by measuring the flow rate at two outfalls, delineating the drainage areas for each outfall, and calculating the volume of the stormwater discharges. Stormwater-discharge samples were collected and analyzed to determine the quality of the discharges. Constituent loads and loads per area were estimated for each drainage area. The studied drainage subareas covered approximately 46 percent of the total area of the Las Flores Industrial Park. Industrial groups represented in the study areas include manufacturers of textile, electronics, paper, fabricated metal, plastic, and chemical products. The concentrations of oil and grease (1 to 6 milligrams per liter), biochemical oxygen demand (4.7 to 16 milligrams per liter), total organic carbon (5.8 to 36 milligrams per liter), total suspended solids (28 to 100 milligrams per liter), and total phosphorous (0.11 to 0.78 milligrams per liter) from all the samples collected were less than the U.S. Environmental Protection Agency stormwater benchmark concentrations. Concentrations of chemical oxygen demand (15.8 to 157 milligrams per liter) and nitrate and nitrite (0.06 to 1.75 milligrams per liter) exceeded benchmark concentrations at one of the studied drainage areas. Total Kjeldahl nitrogen concentrations (1.00 to 3.20 milligrams per liter) exceeded the benchmark concentrations at the two studied drainage areas. Maximum concentrations for oil and grease, biochemical oxygen demand, chemical oxygen demand, total organic carbon, total Kjeldahl nitrogen, nitrate plus nitrite, and total phosphorous were detected in an area where electronics, plastics, and chemical products are currently manufactured. The maximum concentration of total suspended solids was detected at an area where textile, paper, plastic, chemical, and fabricated metal products are manufactured.

  10. Molecular insight into the activity of LasR protein from Pseudomonas aeruginosa in the regulation of virulence gene expression by this organism.

    PubMed

    Chowdhury, Nilkanta; Bagchi, Angshuman

    2016-04-10

    Pseudomonas aeruginosa is an opportunistic human pathogen. This organism attacks human patients suffering from diseases like AIDS, cancer, cystic fibrosis, etc. One of the important virulent factors produced by this organism is Hydrogen Cyanide. This is expressed from the genes encoded by the hcnABC operon. The expressions of the genes encoded by hcnABC operon are mediated mainly by the interactions of LasR protein with the corresponding promoter region of the hcnABC operon. The LasR protein acts as a dimer and binds to the promoter DNA with the help of an autoinducer ligand. However, till date the detailed molecular mechanism of how the LasR protein interacts with the promoter DNA is not clearly known. Therefore, in this work, an attempt has been made to analyze the mode of interactions of the LasR protein with the promoter DNA region of the hcnABC operon. We analyzed the three dimensional structure of the LasR protein from Pseudomonas aeruginosa and docked the protein with the autoinducer ligand. We then docked the ligand-bound-LasR-protein as well the LasR-protein-without-the-autoinducer-ligand on to the promoter DNA region of hcnABC operon. We analyzed the details of the interaction profiles of LasR protein with the autoinducer ligand. We also deciphered the details of the LasR promoter-DNA interactions. We compared the modes of DNA bindings by the LasR protein in presence and absence of the autoinducer ligand and tried to analyze the molecular details of the binding of LasR protein with the promoter DNA region of hcnABC operon during hcnABC gene expression. This study may therefore pave the pathway for future experiments to determine the relative effects of the amino acid residues of LasR protein in DNA binding during the transcription of hcnABC operon.

  11. Unraveling the contributions of hydrogen-bonding interactions to the activity of native and non-native ligands in the quorum-sensing receptor LasR

    PubMed Central

    Gerdt, Joseph P.; McInnis, Christine E.; Schell, Trevor L.; Blackwell, Helen E.

    2014-01-01

    Quorum sensing (QS) via the synthesis and detection of N-acyl L-homoserine lactone (AHL) signals regulates important pathogenic and mutualistic phenotypes in many bacteria. Over the past two decades, the development of non-native molecules that modulate this cell-cell signaling process has become an active area of research. The majority of these compounds were designed for block binding of the native AHL signal to its cognate LuxR-type receptor, and much effort has focused on LasR in the opportunistic pathogen Pseudomonas aeruginosa. Despite a small set of reported LasR structural data, it remains unclear which polar interactions are most important for either (i) activation of the LasR receptor by its native AHL signal, N-(3-oxo)-dodecanoyl L-homoserine lactone (OdDHL), or (ii) activation or inhibition of LasR by related AHL analogs. Herein, we report our investigations into the activity of OdDHL and five synthetic analogs in wild-type LasR and in nine LasR mutants with modifications to key polar residues in their ligand binding sites. Our results allowed us to rank, for the first time, the relative importance of each LasR:OdDHL hydrogen bond for LasR activation and provide strong evidence for the five synthetic ligands binding LasR in a very similar orientation as OdDHL. By delineating the specific molecular interactions that are important for LasR modulation by AHLs, these findings should aid in the design of new synthetic modulators of LasR (and homologous LuxR-type receptors) with improved potencies and selectivities. PMID:25474181

  12. Can a Spanish Science Education Journal Become International? The Case of "Enseñanza De Las Ciencias"

    ERIC Educational Resources Information Center

    Espinet, Mariona; Izquierdo, Mercè; Garcia-Pujol, Clara

    2015-01-01

    In this paper we discuss the case of the science education research journal "Enseñanza de las Ciencias" ("EC") around the issue of its internationalization and the consequences this process has had and is still having on the use and preservation of different languages and more specifically the Castilian (Spanish) language. We…

  13. Seasonal and diurnal analysis of NO2 concentrations from a long-duration study conducted in Las Vegas, Nevada

    EPA Science Inventory

    A study, conducted in Las Vegas, NV from mid-December 2008 to mid-December 2009 along an interstate highway, collected continuous and integrated ambient air quality samples for a wide variety of species including NO2 and NOX. Previous near-road studies have been short duration, ...

  14. Ambient air monitoring during the 2011 Las Conchas wildland fire near Los Alamos, U.S.A.

    SciTech Connect

    Green, Andrew A.; Schlemann, Shea A.; Young, Daniel L.

    2012-08-31

    Air monitoring data collected during the Las Conchas fire near the Los Alamos National Laboratory during 2011 are presented. Data included are for selected radionuclides and selected metals found in particulate matter. None of these analytes were seen at levels which exceeded any state or federal standards.

  15. Effect of sediment properties on the sorption of C12-2-LAS in marine and estuarine sediments.

    PubMed

    Rico-Rico, Angeles; Temara, Ali; Behrends, Thilo; Hermens, Joop L M

    2009-02-01

    Linear alkylbenzene sulfonates (LAS) are anionic high production volume surfactants used in the manufacture of cleaning products. Here, we have studied the effect of the characteristics of marine and estuarine sediments on the sorption of LAS. Sorption experiments were performed with single sediment materials (pure clays and sea sand), with sediments treated to reduce their organic carbon content, and with field marine and estuarine sediments. C12-2-LAS was used as a model compound. Sorption to the clays montmorillonite and kaolinite resulted in non-linear isotherms very similar for both clays. When reducing the organic content, sorption coefficients decreased proportionally to the fraction removed in fine grain sediments but this was not the case for the sandy sediment. The correlation of the sediment characteristics with the sorption coefficients at different surfactant concentrations showed that at concentrations below 10 microg C12-2-LAS/L, the clay content correlated better with sorption, while the organic fraction became more significant at higher concentrations.

  16. Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

    PubMed Central

    Lidor, O.; Al-Quntar, A.; Pesci, E. C.; Steinberg, D.

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases. PMID:26593271

  17. 77 FR 28569 - Reorganization and Expansion of Foreign-Trade Zone 89 Under Alternative Site Framework, Las Vegas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ... Framework, Las Vegas, NV Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as..., the Board adopted the alternative site framework (ASF) (74 FR 1170, 01/12/2009; correction 74 FR 3987... application to reorganize and expand FTZ 89 under the alternative site framework is approved, subject to...

  18. Preliminary information on ambient concentrations measured at the Las Vegas National Near-Road MSAT study site

    EPA Science Inventory

    This paper provides preliminary information on the trends in ambient concentrations observed near a heavily traveled highway in Las Vegas, Nevada. As part of a joint effort by the U.S. Environmental Protection Agency (EPA) and Federal Highway Administration, an air monitoring pro...

  19. What Happens in Vegas Does "Not" Stay in Vegas: Youth Leadership in the Immigrant Rights Movement in Las Vegas, 2006

    ERIC Educational Resources Information Center

    Revilla, Anita Tijerina

    2012-01-01

    Students calling themselves the Las Vegas Activist Crew shut down the city's famed Strip on May 1, 2006, with an immigrant rights protest that was one of the largest demonstrations in Nevada's history. This research analyzes the ways that students engage in activism to improve their own social conditions and those of their communities. The…

  20. Bartolome de Las Casas; Protector of the Indians. The Tinker Pamphlet Series for the Teaching of Mexican American Heritage.

    ERIC Educational Resources Information Center

    Miller, Hubert J.

    Bartolome de las Casas devoted himself completely to crusading for the rights of the Indians. Although he was never a missionary among Indians, he began projects such as the Indians' conversion in the Land of War in Guatemala, which later became the task of his Dominican colleagues. However, his true importance lay in his role as the Indians'…

  1. El origen de las galaxias en modelos jerárquicos de formación de la estructura

    NASA Astrophysics Data System (ADS)

    Navarro, J. F.

    En esta charla presentaré una revisión de los modelos corrientes de formación de galaxias. En particular, haré énfasis en el origen de la gran variedad de morfologías galácticas y de las correlaciones entre las propiedades estructurales de discos y esferoides, todo dentro del contexto cosmológico jerárquico provisto por teorías como la de materia oscura fría. En este tipo de teorías las correlaciones observadas entre la luminosidad, velocidad de rotación, momento angular, y tamaño de galaxias son el resultado de la falta de escalas naturales en el proceso de formación de los halos de materia oscura que dichas galaxias habitan. Simulaciones numéricas que incorporan efectos gravitacionales, hidrodinámicos y de formación estelar ilustran estas ideas y demuestran las dificultades que aquejan a modelos donde tanto discos como esferoides son el resultado final de una secuencia de fusiones de sistemas protogalácticos.

  2. Female Adolescent Subjectivities in Las Vegas: Poststructural Thoughts on the Intersections of Gender, Sexuality, Consumer Logic and Curriculum

    ERIC Educational Resources Information Center

    Dentith, Audrey M.

    2004-01-01

    In this article, data collected from an ethnographic study of adolescent girls growing up in the city of Las Vegas in the US is used to further our understanding of the role of mediated sex and consumer culture and in relationship to emerging adolescent female identities. Girls in this study articulated a clear sense of their abilities to make…

  3. Growth and production of Donax striatus (Bivalvia: Donacidae) from Las Balsas beach, Gibara, Cuba.

    PubMed

    Ocaña, Frank A

    2015-09-01

    Clams of the genus Donax are worldwide the dominating group of the invertebrate community on sandy beaches. They are primary consumers that provide a significant abundance and biomass to the ecosystem. In the Caribbean, Donax striatus has an important role for nature and human, nonetheless studies on the population dynamics of this beach clam are scarce and no information exists on secondary production of this species. Growth parameters and secondary production of D. striatus were estimated from February 2008 to November 2009 at Las Balsas beach, Northeastern Cuba, in order to provide basic information for management purposes. In each month 45 samples were taken by means of a PVC corer of 0.025 m2 area and sieved with a 1 mm mesh. Animals were measured and weighted with and without shell. A total of 5 471 specimens were collected during the sampling period. Shell length ranged from 2.7-33.3 mm. Growth parameters estimated from length frequency data were L∞ = 36.1 mm, K= 0.8/yr and t0= 0.2/yr. The growth performance resulted in values of Φ'= 3.02. Life span was 2.4 yrs and mortality rate was 3.07 /yr. In 2008, mean abundance of D. striatus ranged between 17.1 - 770.7 ind./m2. In 2009 the lowest mean abundance was 34.4 and the highest was 892.5 ind./m2. During 2009 biomass and production was more than twice higher in comparison with 2008. Individual production showed highest values in the 24 mm shell size (3.74 g/m2.yr) and 25 mm (0.71 g/m2.yr), considering mass with shell and without shell, respectively. During 2009 abundance of individuals with 15 mm shell length or more increased resulting in higher biomass and production, compared to 2008. Using the conversion factor of wet mass to ash free dry mass (AFDM), annual production ranged between 2.87-6.11 g AFDM/m2.yr, resulting in a turnover rate (P/B) between 5.11 and 3.47 in 2008 and 2009, respectively. The rapid growth and high turnover rate of D. striatus suggest a rapid recovery of the population. These

  4. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Virgin River, Nevada

    USGS Publications Warehouse

    Laney, R.L.; Bales, J.T.

    1996-01-01

    This study is the last of a series of eight geohydrologic reconnaissance studies that were done in the Lake Mead National Recreation Area. The studies were done to evaluate the water resources in the recreation area and to identify areas having potential for the development of water supplies that would be adequate for marinas and campgrounds. The study area includes about 250 square miles north of Lake Mead from Las Vegas Wash to the Virgin River (Overton Arm), Nevada. Volcanic rocks, consolidated sedimentary rocks, and unconsolidated to semiconsolidated sedimentary rocks underlie the area. Surface-water sources include the Colorado River, Virgin River, Muddy River, and Las Vegas Wash. Elsewhere in the area, streamflow is meager and extremely variable. Ground water originates from four sources: (1) subsurface flow in local basins, (2) infiltration of water from Lake Mead into permeable rocks near the lake, (3) subsurface flow in valleys of perennial streams, and (4) subsurface flow in consolidated rocks of the Muddy Mountains. The quantity of water from Lake Mead that has saturated rocks adjacent to the lake probably is greater than the quantity of ground water from all the Other sources. Rocks saturated by water from the lake probably extend less than 0.5 mileinland from the lake shore. The quality of virtually all the ground water in the area is not acceptable for drinking purposes. The most favorable areas for obtaining ground water are those underlain by the coarse-grained deposits of the older alluvium and the younger alluvium adjacent to Lake Mead. The least favorable areas are those underlain by the mudstone facies of the Muddy Creek Formation and fine-grained rocks of the Horse Spring Formation. Four areas identified as having potential for ground-water development are (1) near Overton Beach, (2) west of Callville Bay, (3) near Middle Point, and (4) in the lower Moapa Valley. Usable quantities of water probably can be obtained at these sites, but the

  5. Evaluating Water Supply and Water Quality Management Options for Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Ahmad, S.

    2007-05-01

    The ever increasing population in Las Vegas is generating huge demand for water supply on one hand and need for infrastructure to collect and treat the wastewater on the other hand. Current plans to address water demand include importing water from Muddy and Virgin Rivers and northern counties, desalination of seawater with trade- payoff in California, water banking in Arizona and California, and more intense water conservation efforts in the Las Vegas Valley (LVV). Water and wastewater in the LVV are intrinsically related because treated wastewater effluent is returned back to Lake Mead, the drinking water source for the Valley, to get a return credit thereby augmenting Nevada's water allocation from the Colorado River. The return of treated wastewater however, is a major contributor of nutrients and other yet unregulated pollutants to Lake Mead. Parameters that influence the quantity of water include growth of permanent and transient population (i.e., tourists), indoor and outdoor water use, wastewater generation, wastewater reuse, water conservation, and return flow credits. The water quality of Lake Mead and the Colorado River is affected by the level of treatment of wastewater, urban runoff, groundwater seepage, and a few industrial inputs. We developed an integrated simulation model, using system dynamics modeling approach, to account for both water quantity and quality in the LVV. The model captures the interrelationships among many variables that influence both, water quantity and water quality. The model provides a valuable tool for understanding past, present and future pathways of water and its constituents in the LVV. The model is calibrated and validated using the available data on water quantity (flows at water and wastewater treatment facilities and return water credit flow rates) and water quality parameters (TDS and phosphorus concentrations). We used the model to explore important questions: a)What would be the effect of the water transported from

  6. Human-health pharmaceutical compounds in Lake Mead, Nevada and Arizona, and Las Vegas Wash, Nevada, October 2000-August 2001

    USGS Publications Warehouse

    Boyd, Robert A.; Furlong, Edward T.

    2002-01-01

    The U.S. Geological Survey and the National Park Service conducted a reconnaissance study to investigate the occurrence of selected human-health pharmaceutical compounds in water samples collected from Lake Mead on the Colorado River and Las Vegas Wash, a waterway used to transport treated wastewater from the Las Vegas metropolitan area to Lake Mead. Current research indicates many of these compounds can bioaccumulate and may adversely affect aquatic organisms by disrupting physiological processes, impairing reproductive functions, increasing cancer rates, contributing to the development of antibiotic-resistant strains of bacteria, and acting in undesirable ways when mixed with other substances. These compounds may be present in effluent because a high percentage of prescription and non-prescription drugs used for human-health purposes are excreted from the body as a mixture of parent compounds and degraded metabolite compounds; also, they can be released to the environment when unused products are discarded by way of toilets, sinks, and trash in landfills. Thirteen of 33 targeted compounds were detected in at least one water sample collected between October 2000 and August 2001. All concentrations were less than or equal to 0.20 micrograms per liter. The most frequently detected compounds in samples from Las Vegas Wash were caffeine, carbamazepine (used to treat epilepsy), cotinine (a metabolite of nicotine), and dehydronifedipine (a metabolite of the antianginal Procardia). Less frequently detected compounds in samples collected from Las Vegas Wash were antibiotics (clarithromycin, erythromycin, sulfamethoxazole, and trimethoprim), acetaminophen (an analgesic and anti-inflammatory), cimetidine (used to treat ulcers), codeine (a narcotic and analgesic), diltiazem (an antihypertensive), and 1,7-dimethylxanthine (a metabolite of caffeine). Fewer compounds were detected in samples collected from Lake Mead than from Las Vegas Wash. Caffeine was detected in all samples

  7. Revisión de tecnología y riesgos: refinerías de petróleo - Hoja informativa para las comunidades

    EPA Pesticide Factsheets

    La Agencia de Protección Ambiental (EPA, por sus siglas en inglés) emitió un reglamento final que mejorará significativamente la calidad del aire en los vecindarios cercanos a las refinerías de petróleo mediante un control más exhaustivo de las emisiones a

  8. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  9. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  10. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  11. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  12. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  13. Posible culto al sol en los grabados rupestres de Las Hurdes (Cáceres).

    NASA Astrophysics Data System (ADS)

    Sevillano, C.

    The author presents a set of rock engravings located in the region of Las Hurdes (Cäceres) a mountainous region to the west of the Central System of the Iberian Peninsula, which present some characteristics different from the other rock engravings known in the Península. In first place the total lack of a narrative character must be underlined, implying that the idea is transmitted through symbols. Essentially the set is formed by geometric scenes, mainly cycles associated with pictures of steps and standing stones. There do exist several schematic motives of weapons and feet as well. On one of the rocks there exists a Roman inscription. The study centers on the circular motives and their associations with other geometric motives, which suggest a possible solar cult, especially in view of the steps which can define the image of a cart, which could be identified with the image of the solar cart. Similarly, on other rock there appear a series of five-spiked stars associated in one case to weapons and in another with foot prints, which provide evidence for a solar cult. In any case, the symbolic character of the figures represented seems to imply the abstraction of a cult, with a magic religious character, in which the idea of the star cult presides the rock symbolism. From the study of the arms represented and because of the Roman inscription one could assign to the set of engravings a chronology which could go from the megalithic to the time of romanization.

  14. Metallic species in atmospheric particulate matter in Las Palmas de Gran Canaria.

    PubMed

    Cancio, J López; Castellano, A Vera; Hernández, M Chaar; Bethencourt, R García; Ortega, E Macías

    2008-12-30

    In this work, we quantified the total, water-soluble and insoluble fractions of 12 metallic species (Na, Ca, K, Mg, Fe, Zn, Cr, Ni, Cu, Cd, Pb and Mn) present in total suspended particulates (TSP) in an urban area with heavy traffic (about 80 000 vehicles/day) of Las Palmas de Gran Canaria (Canary Islands). Experimental measurements were made from July to December 2003 on a total of 42 samples (7 per month). Particulate matter (TSP) was collected in fiber filters and high volume samplers. PM10 levels were estimated assuming the PM10 fraction is about 70% of all TSP. Total fractions was determined gravimetrically. Water-soluble fraction was extracted by sonication. Concentrations of metallic elements were analyzed by flame atomic absorption spectrophotometer. Temporal changes in the concentrations of the target elements were examined and a multivariate approach used to identify the primary sources for each species. Mean value for TSP is 71.92microg/m3. The water-soluble fraction consisted mainly of Na, Ca, Mg, and K. The insoluble fraction contained higher concentrations of all elements than the soluble except Na. In the water-soluble fraction, Na, K, Ca and Mg were found to come mainly from natural sources; Cr, Pb, Cd, Ni, Zn and Cu from anthropogenic sources.

  15. Understanding Ground Motion in Las Vegas: Insights from Data Analysis and Two-Dimensional Modeling

    SciTech Connect

    Rodgers, A; Tkalcic, H; McCallen, D

    2004-02-05

    Seismic ground motions are amplified in low velocity sedimentary basins relative to adjacent sites on high velocity hard rock. We used historical recordings of NTS nuclear explosions and earthquake recordings in Las Vegas Valley to quantify frequency-dependent basin amplification using Standard Spectral Ratios. We show that amplifications, referred to as site response, can reach a factor of 10 in the frequency band 0.4-2.0 Hz. Band-averaged site response between 0.4-2.0 Hz is strongly correlated with basin depth. However, it is also well known that site response is related to shallow shear-wave velocity structure. We simulated low frequency (f<1Hz) ground motion and site response with two-dimensional elastic finite difference simulations. We demonstrate that physically plausible models of the shallow subsurface, including low velocity sedimentary structure, can predict relative amplification as well as some of the complexity in the observed waveforms. This study demonstrates that site response can be modeled without invoking complex and computationally expensive three-dimensional structural models.

  16. Recovery of Durvillaea antarctica (Durvilleales) inside and outside Las Cruces Marine Reserve, Chile.

    PubMed

    Castilla, J C; Campo, M A; Bustamante, R H

    2007-07-01

    We present the results for over two decades of monitoring on intertidal food-gatherers and the population of the low rocky shore dweller kelp Durvillaea antarctica, a short-distance disperser, inside and outside the no-take marine reserve, Estacion Costera de Investigaciones Marinas (ECIM), at Las Cruces, central Chile. It was hypothesized that protection of an initially extremely depleted population would recover by recolonizing first the no-take area and then adjacent non-protected (exploited) areas. We found that recovery of D. antarctica occurred slowly inside ECIM, with increase in density and biomass, of up to three orders of magnitude as compared to an adjacent non-protected area, which showed approximately 2-yr delay. These results suggest that the kelp population inside ECIM was likely regulated via intraspecific competition, which did not occur outside. Results showed no evidence for juvenile vs. adult density dependence other than a weak relationship for the central area of ECIM. These findings also suggest that the population recovery and cross-boundary seeding subsides affected the population dynamics. Understanding these dynamics may enhance management and conservation policies. Our work highlights the critical value of baseline and long-term comparative studies in marine no-take protected and non-protected areas for understanding how population processes respond to human and conservation practices.

  17. Episodic Impacts from California Wildfires Identified in Las Vegas Near-Road Air Quality Monitoring.

    PubMed

    Kimbrough, Sue; Hays, Michael; Preston, Bill; Vallero, Daniel A; Hagler, Gayle S W

    2016-01-05

    Air pollutant concentrations near major highways are usually attributed to a combination of nearby traffic emissions and regional background, and generally presumed to be additive in nature. During a near-road measurement study conducted in Las Vegas, NV, the effects of distant wildfires on regional air quality were indicated over a several day period in the summer of 2009. Area-wide elevated particulate levoglucosan (maximum of 0.83 μg/m(3)) and roadside measurements of ultraviolet light-absorbing particulate matter (UVPM) in comparison to black carbon (Delta-C) were apparent over the three-day period. Back-trajectory modeling and satellite images supported the measurement results and indicated the transport of air pollutants from wildfires burning in southern California. Separating roadside measurements under apparent biomass burning event (Delta-C > 1000 ng m(-3)) and nonevent (Delta-C < 1000 ng m(-3)) periods, and constraining to specific days of week, wind speed range, wind direction from the road and traffic volume range, roadside carbon monoxide, black carbon, total particle number count (20-200 nm), and accumulation mode particle number count (100-200 nm) increased by 65%, 146%, 58%, and 366%, respectively, when biomass smoke was indicated. Meanwhile, ultrafine particles (20-100 nm) decreased by 35%. This episode indicates that the presence of aged wildfire smoke may interact with freshly emitted ultrafine particles, resulting in a decrease of particles in the ultrafine mode.

  18. [Description of a staphylococcal alimentary poisoning outbreak in Las Rosas, Santa Fe Province, Argentina].

    PubMed

    Brizzio, Aníbal A; Tedeschi, Fabián A; Zalazar, Fabián E

    2011-01-01

    On February 2008, a suspected foodborne outbreak was reported in Las Rosas (Santa Fe Province, Argentina). The formal procedures indicated that an undetermined number of individuals had experienced food poisoning following consumption of vegetable cannelloni bought at a local shop. The manufacturer establishment was audited. Samples from the suspected food, as well as environmental samples and swabs from food handlers were obtained and involved subjects were interviewed. Remnants of ingested food were also obtained. Routine microbiological procedures of the foodborne outbreak revealed the presence of coagulase positive S. aureus subspecies aureus in samples from ingested and raw food, and from manipulators. Indicator microorganisms did not show significant levels and no other foodborne pathogen was isolated. Presence of staphylococcal enterotoxin-producing genes was subsequently investigated, and a positive result for enterotoxin B was shown in S. aureus strains isolated from a food handler as well as from food linked to the outbreak Moreover, these isolates showed 100% similarity by SmaI-PFGE. Timely notification together with coordinated sanitary measures and the availability of appropriate laboratory tools allowed to interrupt the chain of disease transmission by identifying risk and protective factors.

  19. Integrated geophysical methods for studying the karst system of Gruta de las Maravillas (Aracena, Southwest Spain)

    NASA Astrophysics Data System (ADS)

    Martínez-Moreno, F. J.; Galindo-Zaldívar, J.; Pedrera, A.; Teixido, T.; Ruano, P.; Peña, J. A.; González-Castillo, L.; Ruiz-Constán, A.; López-Chicano, M.; Martín-Rosales, W.

    2014-08-01

    In this study we contrast the results of different geophysical methods in order to describe the karst system surrounding of the Gruta de las Maravillas cave (Aracena, Spain). A comprehensive study of the geophysical responses of the known cavity was carried out, after which several sections were studied to detect the karst architecture and cave continuity. To ensure precision, the inner 3D-topography of the cave was determined by classical geodetic techniques and a digital terrain model was performed with differential GPS. The microgravity method was used to obtain the residual gravity map of the entire study zone, whose minima could be related to caves. Then, the negative gravity anomalies were analyzed to plan several lines for implementing further geophysical methods: magnetic profiles (MP), electrical resistivity tomography (ERT), induced polarization (IP), 2D seismic prospection (refraction tomography and reflection sections) and ground penetrating radar (GPR). The resulting models for each line explored were integrated with detailed geological maps to establish the unknown continuity of the caves. Finally, we discuss the suitability of each geophysical technique for cave detection in marble with sulfur host rock and propose the best procedures to constrain their geometries.

  20. Prevalence of ectoparasitic arthropods on wild animals and cattle in the Las Merindades area (Burgos, Spain).

    PubMed

    Domínguez-Peñafiel, G; Giménez-Pardo, C; Gegúndez, Mi; Lledó, L

    2011-08-01

    This paper reports the prevalence of ectoparasitic arthropods in sampled groups of wild (n = 128; 16 species) and domestic (n = 69; 3 species) animals in the Las Merindades area of the Province of Burgos, Spain. The study revealed that wild animals were more infested and with a wider variety of ectoparasites than domestic animals. The parasitic prevalence was 67% for wild animals and 48% for livestock. In this way, 39% of animals were infected by ticks. Ixodes ricinus and Ixodes hexagonus were the most prevalent species whereas Dermacentor reticulatus showed affinity for the fox and wolf. The overall prevalence of parasitisation by fleas was 27%. Ctenophthalmus spp. showed the wider range host in wild animals, while Pulex irritans was the most frequent specie found. The parasitic prevalences by lice (Trichodectes melis, Trichodectes canis and Trichodectes mustelae) and by mite (Neotrombicula spp., Laelaps agilis and Sarcoptes scabiei) were 4% and 12%, respectively. In both cases only wild animals were found parasited.

  1. Exploring the unified class of Type II Supernovae with the Las Cumbres Observatory Global Telescope Network

    NASA Astrophysics Data System (ADS)

    Valenti, Stefano; Howell, Dale Andrew; Sand, David J.; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis

    2015-01-01

    Traditionally Type II supernovae (SNe) have been separated into two distinct classes based on the shape of their light curves after peak: Type II plateau (IIP) and Type II linear (IIL) SNe. Recent works suggest that Type II SNe form a continuum of objects from a single progenitor system. Here we present data for a set of Type II SNe collected with the Las Cumbres Observatory Global Telescope (LCOGT) Network and observed simultaneously with UVOT-Swift. In the growing sample of Type II SNe, we search for clear evidence to distinguish the two classes. SNe IIL show a similar drop at the end of their short steep plateau that resemble the drop visible in SNe IIP. We show that also at early phase SNe IIP and IIL are similar both in the UV and in the optical. Our analysis is consistent with the scenario that SNe IIP and IIL come from similar progenitors but with SN IIL progenitors having been stripped of their hydrogen envelope before explosion. While SNe IIL are on average more luminous than SNe IIP, we show that they both produce a comparable amount of nickel.

  2. Large-scale galaxy distribution in the Las Campanas Redshift Survey

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A. G.; Tucker, D. L.; Fong, R.; Turchaninov, V.; Lin, H.

    2001-04-01

    We make use of three-dimensional clustering analysis, inertia tensor methods, and the minimal spanning tree technique to estimate some physical and statistical characteristics of the large-scale galaxy distribution and, in particular, of the sample of overdense regions seen in the Las Campanas Redshift Survey (LCRS). Our investigation provides additional evidence for a network of structures found in our core sampling analysis of the LCRS: a system of rich sheet-like structures, which in turn surround large underdense regions criss-crossed by a variety of filamentary structures. We find that the overdense regions contain ~40-50 per cent of LCRS galaxies and have proper sizes similar to those of nearby superclusters. The formation of such structures can be roughly described as a non-linear compression of protowalls of typical cross-sectional size ~20-25h-1Mpc this scale is ~5 times the conventional value for the onset of non-linear clustering - to wit, r0, the autocorrelation length for galaxies. The comparison with available simulations and theoretical estimates shows that the formation of structure elements with parameters similar to those observed is presently possible only in low-density cosmological models, Ωmh~0.2-0.3, with a suitable large-scale bias between galaxies and dark matter.

  3. Indicator pathogens, organic matter and LAS detergent removal from wastewater by constructed subsurface wetlands

    PubMed Central

    2014-01-01

    Background Constructed wetland is one of the natural methods of municipal and industrial wastewater treatments with low initial costs for construction and operation as well as easy maintenance. The main objective of this study is to determine the values of indicator bacteria removal, organic matter, TSS, ammonia and nitrate affecting the wetland removal efficiency. Results The average concentration of E. coli and total coliform in the input is 1.127 × 1014 and 4.41 × 1014 MPN/100 mL that reached 5.03 × 1012 and 1.13 × 1014 MPN/100 mL by reducing 95.5% and 74.4% in wetland 2. Fecal streptococcus reached from the average 5.88 × 1014 in raw wastewater to 9.69 × 1012 in the output of wetland 2. Wetland 2 could reduce 1.5 logarithmic units of E. coli. The removal efficiency of TSS for the wetlands is 68.87%, 71.4%, 57.3%, and 66% respectively. Conclusions The overall results show that wetlands in which herbs were planted had a high removal efficiency about the indicator pathogens, organic matter, LAS detergent in comparison to a control wetland (without canes) and could improve physicochemical parameters (DO, ammonia, nitrate, electrical conductivity, and pH) of wastewater. PMID:24581277

  4. [Epidemiology of sexually transmitted diseases in the mine area of Las Claritas, Bolivar State, Venezuela].

    PubMed

    González-O, N; Rodríguez-Acosta, A

    2000-06-01

    The primordial objective of this study was to carry out an epidemiological analysis of sexually transmitted diseases (STD) in terms of sensed morbidity and real morbidity in the mining region of "Las Claritas", Bolivar State, Venezuela, during the third trimester of 1998. The epidemiological characteristics of time, people and place are interlaced, giving a relationship included within the Epidemiological Triad, that represents this work's conceptual framework; defining both, the determinant and the conditioning factors of the presence of STDs in the zone. The clinical interrogatory was partially steered towards the participant's sensed morbidity. A mostly feminine population is described (65%), with a low scholarly level in the general population and a high index of foreigners among the evaluated patients; with 48.72% of stable unions in the interviewees. From 166 evaluated patients, 27.70% referred to have had some STD episode, being syphilis and blenorrhagia the most frequently reported. In the survey, there was a general hush concerning the presence of STDs; but, key informants such as the medicine retailers, revealed a higher presence of these diseases, which are wrongly treated by automedication. These are important results, since they let opened a space for the epidemiological evaluation in the zone, in the various health, sanitary, environmental and social aspects and mainly, by the individual's quality of life expectations.

  5. Random analysis of bearing capacity of square footing using the LAS procedure

    NASA Astrophysics Data System (ADS)

    Kawa, Marek; Puła, Wojciech; Suska, Michał

    2016-09-01

    In the present paper, a three-dimensional problem of bearing capacity of square footing on random soil medium is analyzed. The random fields of strength parameters c and φ are generated using LAS procedure (Local Average Subdivision, Fenton and Vanmarcke 1990). The procedure used is re-implemented by the authors in Mathematica environment in order to combine it with commercial program. Since the procedure is still tested the random filed has been assumed as one-dimensional: the strength properties of soil are random in vertical direction only. Individual realizations of bearing capacity boundary-problem with strength parameters of medium defined the above procedure are solved using FLAC3D Software. The analysis is performed for two qualitatively different cases, namely for the purely cohesive and cohesive-frictional soils. For the latter case the friction angle and cohesion have been assumed as independent random variables. For these two cases the random square footing bearing capacity results have been obtained for the range of fluctuation scales from 0.5 m to 10 m. Each time 1000 Monte Carlo realizations have been performed. The obtained results allow not only the mean and variance but also the probability density function to be estimated. An example of application of this function for reliability calculation has been presented in the final part of the paper.

  6. Neandertal mandibles from the Sima de las Palomas del Cabezo Gordo, Murcia, southeastern Spain.

    PubMed

    Walker, Michael J; Lombardi, A Vincent; Zapata, Josefina; Trinkaus, Erik

    2010-06-01

    The Middle Paleolithic levels of the Sima de las Palomas have yielded eight partial mandibles (Palomas 1, 6, 7, 23, 49, 59, 80, and 88). Palomas 7, 49, 80, and 88 are immature, and Palomas 49, 59, 80, and 88 are among the latest Neandertals (approximately 40,000 cal BP). Palomas 1 is geologically older (approximately 50,000-60,000 cal BP), and the other three were found ex situ. The mandibles exhibit a suite of characteristics that align them with the Neandertals among later Pleistocene humans, including symphyseal morphology, symphyseal orientation, corpus robusticity, distal mental foramen position, retromolar space presence, wide immature dental arcade, and high-coronoid process with an asymmetrical mandibular notch. However, Palomas 6 lacks a retromolar space, Palomas 59 has a narrow lateral corpus, and Palomas 80 has a mesial mental foramen and open mandibular foramen. The Palomas mandibles therefore help to document that the late Middle Paleolithic of southern Iberia was the product of Neandertals. They also reinforce the presence of variability in both metric and discrete aspects of Neandertal mandibular morphology, both within and across samples, some of which may be temporal and/or geographic in nature.

  7. Risk assessment of linear alkylbenzene sulphonates, LAS, in agricultural soil revisited: robust chronic toxicity tests for Folsomia candida (Collembola), Aporrectodea caliginosa (Oligochaeta) and Enchytraeus crypticus (Enchytraeidae).

    PubMed

    Krogh, Paul Henning; Lopez, Coral Verge; Cassani, Giorgio; Jensen, John; Holmstrup, Martin; Schraepen, Nathalie; Jørgensen, Elin; Gavor, Zdenek; Temara, Ali

    2007-10-01

    To obtain robust data on the toxicity of LAS, tests with the collembolan Folsomia candida L., the oligochaetes Aporrectodea caliginosa Savigny (earthworm) and Enchytraeus crypticus Westheide and Graefe (enchytraeid) were performed in a sandy loam soil. Additionally limited tests with LAS spiked to sewage sludge, and subsequently mixed into soil, were performed. For the endpoint of interest, reproduction in soil, we found an EC10 of 205 mg LAS kg(-1) soil [8.6-401] [95% confidence limits] for F. candida and an EC10 of 46 mg LAS kg(-1) soil [13-80] for A. caliginosa after 28 days. E. crypticus was not affected by concentrations up to 120 mg LAS kg(-1) soil. When adding (low contaminated) non-spiked sludge to soil, high stimulation of reproduction was observed for E. crypticus and A. caliginosa but not for F. candida. We argue that this difference in stimulative response between the tested species is related to the difference in feeding behaviour. Sludge spiked with LAS did not significantly affect the reproduction of F. candida (fertility: number of juvenile offspring) and A. caliginosa (fecundity: number of cocoons) (dose equivalent to 181 g and 91 g LAS kg(-1) sludge, respectively). Significantly reduced reproduction was observed for E. crypticus (at 120 mg LAS kg(-1) soil+sludge corresponding to 72 g LAS kg(-1) sludge) compared to non-spiked sludge. The reproduction by E. crypticus was, however, comparable to the reproduction observed in the control soil without sludge. Compared to LAS directly spiked to soil, the reproductive output of organisms exposed to spiked sludge was either not significantly different (F. candida, E. crypticus) or significantly improved (A. caliginosa). More studies are needed in order to make firm conclusions on the potential effect of artificially contaminated sludge in soil systems.

  8. New rapid methods for determination of total LAS in sewage sludge by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE).

    PubMed

    Villar, M; Callejón, M; Jiménez, J C; Alonso, E; Guiraúm, A

    2009-02-23

    Linear alkylbenzene sulfonates (LAS) are the most common synthetic anionic surfactant used in domestic and industrial detergents, with a global production of 2.4x10(6) t year(-1). After use and disposal, LAS may enter the environment by one of the several routes, including by direct discharge to surface water or discharge to water from sewage treatment plants. Sewage treatment plants break down LAS only partly: some of them remain in effluent and other fraction is adsorbed in sewage solid. New and rapid methods for determination of total LAS from sewage sludge based on microwave assisted extraction and HPLC-FL and CE-DAD determination are proposed. The extraction of total LAS is carried out by using microwaves energy, an extraction time of 10 min and 5 mL of methanol. For HPLC-FL determination, mobile phase acetonitrile-water was used, comprising 60% (v/v) from 0 to 1 min and a flow rate of 1 mL min(-1) programmed to 100% acetonitrile between 1 and 2 min and a flow rate of 2 mL min(-1). The final composition was maintained for a further 5 min. The determination of total LAS by CE-DAD was performed in a phosphate buffer (10 mM, pH 9). The separation voltage was 25 kV and the temperature of the capillary was 30 degrees C. Injections were performed in the pressure mode and the injection time was set at 12 s. The determination of total LAS is carried out in less than 5 min. The methods did not require clean-up or preconcentration steps. Detection limit for total LAS in the sludge was 3.03 mg kg(-1) using HPLC-FL and 21.0 mg kg(-1) using CE-DAD, and recoveries were >85% using both determination methods. Concentrations of total LAS obtained using both methods were compared with the sum of concentrations of homologues LAS C-10, LAS C-11, LAS C-12 and LAS C-13 obtained using microwaves assisted extraction and HPLC-FL and CE-DAD determination.

  9. SOURCE AND PATHWAY DETERMINATION FOR BERYLLIUM FOUND IN BECHTEL NEVADA NORTH LAS VEGAS FACILITIES

    SciTech Connect

    BECHTEL NEVADA

    2004-07-01

    In response to the report ''Investigation of Beryllium Exposure Cases Discovered at the North Las Vegas Facility of the National Nuclear Security Administration'', published by the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) in August 2003, Bechtel Nevada (BN) President and General Manager Dr. F. A. Tarantino appointed the Beryllium Investigation & Assessment Team (BIAT) to identify both the source and pathway for the beryllium found in the North Las Vegas (NLV) B-Complex. From September 8 to December 18, 2003, the BIAT investigated the pathway for beryllium and determined that a number of locations existed at the Nevada Test Site (NTS) which could have contained sufficient quantities of beryllium to result in contamination if transported. Operations performed in the B-1 Building as a result of characterization activities at the Engine Maintenance, Assembly, and Disassembly (EMAD); Reactor Maintenance, Assembly, and Disassembly (RMAD); Test Cells A and C; and the Central Support Facility in Area 25 had the greatest opportunity for transport of beryllium. Investigative monitoring and sampling was performed at these sites with subsequent transport of sample materials, equipment, and personnel from the NTS to the B-1 Building. The timeline established by the BIAT for potential transport of the beryllium contamination into the B-1 Building was from September 1997 through November 2002. Based on results of recently completed swipe sampling, no evidence of transport of beryllium from test areas has been confirmed. Results less than the DOE beryllium action level of 0.2 ???g/100 cm2 were noted for work support facilities located in Area 25. All of the identified sites in Area 25 worked within the B-1 tenant's residency timeline have been remediated. Legacy contaminants have either been disposed of or capped with clean borrow material. As such, no current opportunity exists for release or spread of beryllium contamination. Historical

  10. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

    PubMed Central

    Goossens, Dirk

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

  11. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA.

    PubMed

    Goossens, Dirk; Buck, Brenda J; Teng, Yuanxin; McLaurin, Brett T

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g(-1) in topsoil and bedrock, and more than 0.03 μg m(-3) in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m(-3). The results of this study are important because the NDRA is visited by more than 300,000 people annually.

  12. The Membrane Protein LasM Promotes the Culturability of Legionella pneumophila in Water

    PubMed Central

    Li, Laam; Faucher, Sébastien P.

    2016-01-01

    The water-borne pathogen Legionella pneumophila (Lp) strongly expresses the lpg1659 gene in water. This gene encodes a hypothetical protein predicted to be a membrane protein using in silico analysis. While no conserved domains were identified in Lpg1659, similar proteins are found in many Legionella species and other aquatic bacteria. RT-qPCR showed that lpg1659 is positively regulated by the alternative sigma factor RpoS, which is essential for Lp to survive in water. These observations suggest an important role of this novel protein in the survival of Lp in water. Deletion of lpg1659 did not affect cell morphology, membrane integrity or tolerance to high temperature. Moreover, lpg1659 was dispensable for growth of Lp in rich medium, and during infection of the amoeba Acanthamoeba castellanii and of THP-1 human macrophages. However, deletion of lpg1659 resulted in an early loss of culturability in water, while over-expression of this gene promoted the culturability of Lp. Therefore, these results suggest that lpg1659 is required for Lp to maintain culturability, and possibly long-term survival, in water. Since the loss of culturability observed in the absence of Lpg1659 was complemented by the addition of trace metals into water, this membrane protein is likely a transporter for acquiring essential trace metal for maintaining culturability in water and potentially in other metal-deprived conditions. Given its role in the survival of Lp in water, Lpg1659 was named LasM for Legionella aquatic survival membrane protein. PMID:27734007

  13. Flow and transport at the Las Cruces trench site: Experiment IIb

    SciTech Connect

    Vinson, J.; Hills, R.G.; Wierenga, P.J.; Young, M.H.

    1997-07-01

    The US Nuclear Regulatory Commission (NRC) has been directed by Congress in the Low Level Waste Policy Act of 1980 to develop regulatory guidance and assist the individual states and compacts in siting and assessing future low level radioactive waste (LLW) disposal facilities. Three water flow and solute transport experiments were performed as part of a comprehensive field trench study near Las Cruces, New Mexico to test deterministic and stochastic models of vadose zone flow and transport. This report presents partial results from the third experiment (experiment IIb). Experiments IIa and b were conducted on the North side of the trench, on a plot 1.22 m wide by 12 m long, perpendicular to the trench. The area was drip irrigated during two time periods with water containing a variety of tracers. The advance of the water front during the two irrigation episodes was measured with tensiometers and neutron probes. Solute front positions were determined from soil solution sampling through suction samplers and from disturbed sampling. The results from experiment IIb show predominantly downward water movement through the layered unsaturated soil, as evidenced from neutron probe data and gravimetric sampling. Tritium plumes were only half as deep and half as wide as the water plumes at 310 days after the beginning of experiment IIb. Chromium, applied as Cr(VI), moved a readily as, and similar to tritium, but there was a loss of mass due to reduction of Cr(VI) to Cr(III). Chloride and nitrate, initially present at high concentrations in the soil solution, were displaced by the low concentration irrigation water, resulting in chloride and nitrate concentration distributions that looked like negative images of the tritium distributions. The extensive data presented should serve well as a data base for model testing.

  14. The Las Cumbres Observatory (LCOGT) Network for NEO and Solar System Science

    NASA Astrophysics Data System (ADS)

    Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric J.; Larson, Stephen M.

    2016-01-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter telescopes to four locations in the northern and southern hemispheres, with a planned network size of twelve 1-meter telescopes at 6 locations. This 1-meter network is in addition to the two 2-meter Faulkes Telescopes that have been operating since 2005. This network is very versatile and is designed to respond rapidly to target of opportunity events and also to perform long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects e.g. Near-Earth Objects (NEOs), comets, asteroids and Kuiper Belt Objects and also for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016-2017.I will describe the Solar System science research that is being carried out using the LCOGT Network with highlights from the LCOGT NEO Follow-up Network, long-term monitoring of the Rosetta spacecraft target comet 67P and comet C/2013 A1 (Siding Spring) and work on Kuiper Belt Object occultation targets, including Pluto.

  15. The Las Cumbres Observatory (LCOGT) Network for NEO and Solar System Science

    NASA Astrophysics Data System (ADS)

    Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric; Larson, Stephen

    2015-11-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter telescopes to four locations in the northern and southern hemispheres, with a planned network size of twelve 1-meter telescopes at 6 locations. This 1-meter network is in addition to the two 2-meter Faulkes Telescopes that have been operating since 2005. This network is very versatile and is designed to respond rapidly to target of opportunity events and also to perform long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects e.g. Near-Earth Objects (NEOs), comets, asteroids and Kuiper Belt Objects and also for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016-2017.I will describe the Solar System science research that is being carried out using the LCOGT Network with highlights from the LCOGT NEO Follow-up Network, long-term monitoring of the Rosetta spacecraft target comet 67P and comet C/2013 A1 (Siding Spring) and work on Kuiper Belt Object occultation targets, including Pluto.

  16. Geology of Volcan Las Navajas, a pleistocene trachyte/peralkaline rhyolite volcanic center in Nayarit, Mexico

    SciTech Connect

    Hegre, J.A.; Nelson, S.A.

    1985-01-01

    Volcan Las Navajas, located in the northwestern portion of the Mexican Volcanic Belt has produced a sequence of volcanic rocks with compositions in marked contrast to the predominantly calc-alkaline volcanoes which predominate in this part of Mexico. The oldest exposed lavas consist of trachytes with 63% SiO/sub 2/, 6% FeO*, and 500 ppm Zr along with comenditic rhyolites with 68% SiO/sub 2/, 5% FeO*, 800 ppm Zr, and an agpaitic index of 1.0. These lavas were followed by the eruption of a comenditic ash-flow tuff and the formation of a caldera 2.7 km in diameter. This caldera was subsequently filled by eruptions of pantelleritic rhyolite obsidian lava flows with 72% SiO/sub 2/, 8% FeO*, 1100 ppm Zr, and an agpaitic index of 1.5 to 1.9. A second caldera was then formed which is offset to the south of the main eruptive vents for previous eruptions. This younger caldera has a diameter of about 4.8 km and its southern walls have been covered by calc-alkaline andesitic lavas erupted from nearby Sanganguey volcano. Volcanoclastic sediments in the floor of the younger caldera have been tilted and faulted in a manner suggestive of late stage resurgence. Subsequent eruptions within the caldera, however, have been restricted to calc-alkaline andesites. Tectonically, the area in which this volcano occurs appears to have been undergoing a crustal rifting event since the Pliocene. The occurrence of these peralkaline rocks lends further support to such a hypothesis.

  17. Response times and outcomes for cardiac arrests in Las Vegas casinos.

    PubMed

    Karch, S B; Graff, J; Young, S; Ho, C H

    1998-05-01

    This study was conducted to measure emergency medical services (EMS) response times in sudden out-of-hospital cardiac arrests and relate those times to probability of survival in cardiac arrest victims in Las Vegas casino-hotels from January 1993 to June 1996. Times from 911 activation to casino arrival and casino arrival to arrival at patient's side (time to first defibrillatory shock), as well as survival to hospital discharge, were studied with regression analysis. Sixty patients survived (29.3%). Response times to the hotels for survivors and nonsurvivors were similar (4.8 v 5.6 min, P = .44). However, times from arrival at the casino to arrival at the patient's side (5.0 v 6.88 min, P = .01) and elapsed times from 911 activation until first shock (9.88 v 12.46 min, P = .02) were substantially longer for nonsurvivors. Model fitting disclosed that with a 911-to-shock time of 4 minutes, survival probability was 36%. Odds decreased by 5% each minute, to 19% after 23 minutes. Ventricular fibrillation was the most common initial rhythm (187 cases) and was associated with the shortest times from 911 to shock (10.7 +/- 7.8 min). There was a strong trend to increased survival with ventricular fibrillation. The 911-to-shock times in this study are considerably better than in other published reports for large metropolitan EMS systems, but the time from 911 to shock was nearly 3 minutes longer for nonsurvivors, and even those defibrillated at 4 minutes had only a 36% chance of survival. New measures, including use of the automatic external difibrillator, to reduce the "vertical" response are urgently needed.

  18. Variations in alluvial style of Tertiary units in response to tectonism, Las Monas area, middle Magdalena valley, Colombia

    SciTech Connect

    Jordan, D.W.; Siemers, C.T.

    1989-03-01

    Detailed sedimentologic and petrographic analyses of Tertiary alluvial sandstone outcrops within and east of producing oil fields in the Las Monas area in Colombia, South America, indicate that depositional style changed from fluvial-deltaic to braided streams atop alluvial fans to high-sinuosity meandering streams in response to uplifts in the surrounding areas. Diverse paleocurrent trends in the Tertiary formations in the perimeter area demonstrate that streams flowed northeast and northwest. Streams in the oil field had easterly and southerly components. Source areas contributing sediment were different and reflected uplifts to the west and south of the Las Monas area. Petrographic composition of sandstones that have easterly and southerly paleocurrent trends in the field area contain more feldspar and less polycrystalline strained quartz than sandstones having a northerly trend in the perimeter area. Sandstones in the field area represent an unroofing of a western granitic terrain, possibly in the ancestral Central Cordillera.

  19. Estudio del comportamiento tribologico y de las interacciones de superficie de nuevos nanofluidos ionicos

    NASA Astrophysics Data System (ADS)

    Espinosa Rodriguez, Tulia

    tribocorrosion processes. The formation of a coating layer on magnesium alloys from phosphonate imidazolium ionic liquids by immersion and by chronoamperometry has been described. The new coatings reduce the abrasive wear in the magnesium-aluminium alloy but they are not effective in the magnesium-zinc alloy, which prevent the formation of continuous coatings. Los liquidos ionicos son sales liquidas a temperatura ambiente o bajas temperaturas que presentan excelentes propiedades fisico-quimicas. En el presente trabajo se estudian como lubricantes en problemas tribologicos complejos como la lubricacion de metales contra si mismos, el desarrollo de lubricantes base agua y de nuevas superficies autolubricadas. Cuando no es posible reducir la friccion y desgaste mediante lubricacion, como en las aleaciones de magnesio, los liquidos ionicos se han estudiado como precursores de recubrimientos protectores. Se han determinado las interacciones superficiales y los procesos de corrosion sobre cobre y sobre acero con diferentes liquidos ionicos proticos y aproticos para desarrollar nuevos lubricantes y aditivos. En el contacto cobre/cobre, excepto el liquido ionico protico derivado del oleato, todos los liquidos ionicos estudiados presentan mejor comportamiento tribologico que el lubricante comercial Polialfaolefina 6. En el contacto acero/zafiro, los nuevos liquidos ionicos proticos son buenos lubricantes cuando se utilizan en estado puro, y, como aditivos en agua, generan peliculas adsorbidas sobre la superficie del metal reduciendo la friccion y el desgaste tras la evaporacion del agua. Para evitar el periodo de alta friccion inicial en presencia de agua, se han generado peliculas superficiales de liquido ionico sobre el acero en condiciones estaticas. El mejor comportamiento lubricante tanto en el contacto cobre/cobre como en el contacto acero/zafiro se obtiene para el liquido ionico protico derivado del anion adipato, con dos grupos carboxilicos. Las interacciones de los grupos

  20. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA1

    PubMed Central

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma. Emily; Medina-Mora, Dra. Ma. Elena

    2010-01-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio. La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos. Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos. PMID:20830214

  1. Recent variation of the Las Vacas Glacier Mt. Aconcagua region, Central Andes, Argentina, based on ASTER stereoscopic images

    NASA Astrophysics Data System (ADS)

    Lenzano, M. G.; Leiva, J. C.; Lenzano, L.

    2010-01-01

    This work presents the results of the ASTER stereoscopic image processing to calculate the volume changes of Las Vacas Glacier. The processing of medium resolution satellite images (ASTER level 1A - pixel 15 m) from February 2001 and 2007 was performed applying the satellite digital photogrammetry method (Kääb, 2005). The comparison of the two generated DTM returns results that are acceptable within the parameters and precisions that can be obtained with this kind of sensor and the processing methodology.

  2. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA.

    PubMed

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma Emily; Medina-Mora, Dra Ma Elena

    2010-06-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio.La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos.Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos.

  3. Elucidating Key Motifs Required for Arp2/3-Dependent and Independent Actin Nucleation by Las17/WASP

    PubMed Central

    Urbanek, Agnieszka N.; Smaczynska-de Rooij, Iwona I.

    2016-01-01

    Actin nucleation is the key rate limiting step in the process of actin polymerization, and tight regulation of this process is critical to ensure actin filaments form only at specific times and at defined regions of the cell. Arp2/3 is a well-characterised protein complex that can promote nucleation of new filaments, though its activity requires additional nucleation promotion factors (NPFs). The best recognized of these factors are the WASP family of proteins that contain binding motifs for both monomeric actin and for Arp2/3. Previously we demonstrated that the yeast WASP homologue, Las17, in addition to activating Arp2/3 can also nucleate actin filaments de novo, independently of Arp2/3. This activity is dependent on its polyproline rich region. Through biochemical and in vivo analysis we have now identified key motifs within the polyproline region that are required for nucleation and elongation of actin filaments, and have addressed the role of the WH2 domain in the context of actin nucleation without Arp2/3. We have also demonstrated that full length Las17 is able to bind liposomes giving rise to the possibility of direct linkage of nascent actin filaments to specific membrane sites to which Las17 has been recruited. Overall, we propose that Las17 functions as the key initiator of de novo actin filament formation at endocytic sites by nucleating, elongating and tethering nascent filaments which then serve as a platform for Arp2/3 recruitment and function. PMID:27637067

  4. Analysis of the real estate market in Las Vegas: Bubble, seasonal patterns, and prediction of the CSW indices

    NASA Astrophysics Data System (ADS)

    Zhou, Wei-Xing; Sornette, Didier

    2008-01-01

    We analyze 27 house price indices of Las Vegas from June 1983 to March 2005, corresponding to 27 different zip codes. These analyses confirm the existence of a real estate bubble, defined as a price acceleration faster than exponential, which is found, however, to be confined to a rather limited time interval in the recent past from approximately 2003 to mid-2004 and has progressively transformed into a more normal growth rate comparable to pre-bubble levels in 2005. There has been no bubble till 2002 except for a medium-sized surge in 1990. In addition, we have identified a strong yearly periodicity which provides a good potential for fine-tuned prediction from month to month. A monthly monitoring using a model that we have developed could confirm, by testing the intra-year structure, if indeed the market has returned to “normal” or if more turbulence is expected ahead. We predict the evolution of the indices one year ahead, which is validated with new data up to September 2006. The present analysis demonstrates the existence of very significant variations at the local scale, in the sense that the bubble in Las Vegas seems to have preceded the more global USA bubble and has ended approximately two years earlier (mid-2004 for Las Vegas compared with mid-2006 for the whole of the USA).

  5. Aerosol Light Absorption and Scattering in Mexico City: Comparison With Las Vegas, NV, and Los Angeles, CA.

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.; Campbell, D.; Fujita, E.

    2007-12-01

    Aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The primary site in Mexico City was an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). Similar campaigns were held in Las Vegas, NV in January-February, 2003; and Los Angeles, CA at numerous sites during all seasons from 2003 through 2007. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The photoacoustic instrument (PAS) used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In Mexico City the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of Mexico City resulted in more direct solar radiation. Further insight on the meteorological connections and population dynamics will be discussed.

  6. Removal of nutrients and metals by constructed and naturally created wetlands in the Las Vegas Valley, Nevada.

    PubMed

    Adhikari, Achyut R; Acharya, Kumud; Shanahan, Seth A; Zhou, Xiaoping

    2011-09-01

    Increased water use associated with rapid growth in the Las Vegas Valley has inadvertently led to the creation of unique wetland systems in Southern Nevada with an abundance of biological diversity. Constructed and naturally created wetlands in the Las Vegas Valley watershed were studied to characterize and understand their potential role for improving ecosystem services (i.e., water purification). Nutrient and metal removal was assessed at four sites including a natural urban runoff wetland, a constructed urban runoff wetland, a constructed wastewater wetland, and a natural urban runoff/wastewater wetland. Plant nutrient uptake was dependent on ambient nutrient concentrations in water and sediments of specific wetlands, irrespective of the type of plants present. Phosphorus was mostly concentrated in below-ground plant parts whereas nitrogen was concentrated in above-ground parts. As for metalloids, bulrushes were more efficient than cattails at taking up arsenic and selenium. Averaging all the wetland sites and plant species, total nitrogen, phosphorus, arsenic and selenium removal was 924.2, 61.5, 0.30, and 0.38 kg/ha/year, respectively. Our findings suggest that natural and created wetland systems can improve water quality in the Las Vegas Valley watershed for some common pollutants, however, other measures are still needed to improve water quality below regulatory thresholds.

  7. The U.S. Department of Energy Office of Indian Energy Policy and Programs Las Vegas, Nevada, Roundtable Summary

    SciTech Connect

    2011-03-16

    LAS VEGAS EXECUTIVE SUMMARY The Las Vegas, Nevada DOE Tribal Roundtable convened on March 16th, at the Las Vegas Hilton. The meeting was hosted by the Department of Energy (DOE) Office of Indian Policy and Programs (DOE Office of Indian Energy) and facilitated by JR Bluehouse, Program Manager, Udall Foundation’s U.S. Institute for Environmental Conflict Resolution (U.S. Institute). Mr. Bluehouse was assisted by Tamara, Underwood, Program Assistant, U.S. Institute.  Tribal leaders and representatives from multiple tribal governments and communities attended the roundtable. Tracey LeBeau, newly appointed Director of the Office of Indian Energy attended.    LaMont Jackson from DOE’s Office of Electricity attended. Also attending from the administration and federal agencies were Kim Teehee, Senior Policy Advisor for Native American Affairs, The White House; Charlie Galbraith, Associate Director of the Office of Public Engagement and Deputy Associate Director of the Office of Intergovernmental Affairs, The White House; Jodi Gillette, Deputy Assistant Secretary for Policy and Economic Development, the Bureau of Indian Affairs.

  8. Improved estimation of sensible heat flux by a LAS using a Bowen ratio at urban residential area

    NASA Astrophysics Data System (ADS)

    Park, M. S.; Chae, J. H.

    2014-12-01

    A large aperture scintillometer (LAS) data sampled for the period from 1 February to 31 July 2014 at urban residential area in Seoul are modified using the variable Bowen ratio and a net radiation data to determine the space-averaged sensible heat flux (SHF). A LAS system is installed over the rooftop of two buildings with a distance between receiver and transmitter of 535 m, an effective height of 18.4 m, a wind speed sensor at 25.0 m high. The path-averaged building height, roughness length, and displacement length between the receiver and transmitter are 9.2 m, 0.4 m, and 7.1 m, respectively. The Bowen ratio computed at every 30 minute interval by the wind speed and air temperature at 10 and 18 m above the rooftop is found to be well correlated with meteorological variables such as net radiation and mixing ratio. Therefore, it is parameterized as a function of mixing ratio and net radiation. The resulting parameterization is applied to estimate the SHF by LAS. The Monin-Obukhov similarity universal function should be changed according to the atmospheric stability using the sign of net radiation sampled at the same time. It is found that the resulting sensible heat fluxes are available under all atmospheric stability and are much improved compared with those by eddy covariance method.

  9. Contribución al flujo infrarrojo de las estrellas Be de la recombinación dielectrónica del MgII

    NASA Astrophysics Data System (ADS)

    Cruzado, A.; di Rocco, H.; Ringuelet, A.

    Para evaluar la contribución del proceso de recombinación dielectrónica del átomo de MgII al exceso de flujo infrarrojo observado en las estrellas Be, calculamos la energía emitida en las líneas originadas por este proceso. Se evaluaron los efectos de las condiciones físicas del medio, como la temperatura electrónica y la densidad electrónica, sobre el flujo emitido. Se consideró también la influencia de una posible opacidad.

  10. Integration of aquatic fate and ecological responses to linear alkyl benzene sulfonate (LAS) in model stream ecosystems.

    PubMed

    Belanger, S E; Bowling, J W; Lee, D M; LeBlanc, E M; Kerr, K M; McAvoy, D C; Christman, S C; Davidson, D H

    2002-06-01

    An integrated model stream ecosystem fate and effect study of dodecyl linear alkylbenzene sulfonate (C(12)LAS) was performed in the summer and fall of 1996. The study addressed responses of periphytic microbes, immature benthic fauna including abundance, drift, and emergence of adult insects in a 56-day exposure. Exposures ranged from 126 to 2978 microg/L and were continuously presented in a single-pass, flow-through test system. Microbial heterotrophs acclimated to C(12)LAS exposure quickly (14 days) and biodegraded C(12)LAS at all concentrations. Blue-green algae responded by increasing in abundance with increasing C(12)LAS concentration. Invertebrates responded by increased drift and reduced benthic abundances at concentrations exceeding 293 microg/L. Emergence at 927 microg/L also declined relative to the control. Adverse responses for mayflies and chironomids were indicated using univariate statistical techniques. Multivariate techniques indicated these taxa plus mollusks, aquatic worms, caddisflies, and stoneflies were impaired at some concentrations. Bioavailability of C(12)LAS was investigated in streams as a function of the total suspended solid load in the water column driven by local weather and watershed patterns. A continuous bioavailability model indicated exposure was reduced by an average of 8.5+/-8.9%. A model ecosystem no-observed-effect concentration (NOEC) was concluded to be 293 microg/L based on measured water column exposure and adjusted to 268 microg/L by the bioavailability model. A literature review of 13 available model ecosystem studies was conducted and NOEC conclusions were adjusted by a structure-activity relationship to a dodecyl chain length (sulfophenyl position and distribution being ignored due to lack of information in the reviewed studies). Lentic studies (n=7) were found to have higher NOECs than lotic studies (n=6) and were more variable. Mean NOECs+/-SD for all studies, lentic studies only, and lotic studies only were 3320

  11. Reconciling Scale Mismatch in Water Governance, Hydro-climatic Processes and Infrastructure Systems of Water Supply in Las Vegas

    NASA Astrophysics Data System (ADS)

    Garcia, M. E.; Alarcon, T.; Portney, K.; Islam, S.

    2013-12-01

    Water resource systems are a classic example of a common pool resource due to the high cost of exclusion and the subtractability of the resource; for common pool resources, the performance of governance systems primarily depends on how well matched the institutional arrangements and rules are to the biophysical conditions and social norms. Changes in water governance, hydro-climatic processes and infrastructure systems occur on disparate temporal and spatial scales. A key challenge is the gap between current climate change model resolution, and the spatial and temporal scale of urban water supply decisions. This gap will lead to inappropriate management policies if not mediated through a carefully crafted decision making process. Traditional decision support and planning methods (DSPM) such as classical decision analysis are not equipped to deal with a non-static climate. While emerging methods such as decision scaling, robust decision making and real options are designed to deal with a changing climate, governance systems have evolved under the assumption of a static climate and it is not clear if these methods are well suited to the existing governance regime. In our study, these questions are contextualized by examining an urban water utility that has made significant changes in policy to adapt to changing conditions: the Southern Nevada Water Authority (SNWA) which serves metropolitan Las Vegas. Like most desert cities, Las Vegas exists because of water; the artesian springs of the Las Vegas Valley once provided an ample water supply for Native Americans, ranchers and later a small railroad city. However, population growth has increased demands far beyond local supplies. The area now depends on the Colorado River for the majority of its water supply. Natural climate variability with periodic droughts has further challenged water providers; projected climate changes and further population growth will exacerbate these challenges. Las Vegas is selected as a case

  12. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    NASA Astrophysics Data System (ADS)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  13. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

    USGS Publications Warehouse

    Laney, R.L.

    1981-01-01

    The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

  14. Las Cumbres Observatory Global Telescope Network: Keeping Citizen Scientists in the Dark

    NASA Astrophysics Data System (ADS)

    Ross, R. J.

    2012-08-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) is creating a network of telescopes at excellent sites around the world providing 24/7 all sky coverage for astronomical observations. The network of telescopes, ranging in size from 0.4 m to 2.0 m, will be available for both scientific and education users. The LCOGT telescopes are being built quickly and will be deployed soon. The two 2.0 m Faulkes Telescopes, one on Haleakala, Maui (FTN), the other at Siding Spring Observatory, Australia (FTS), are currently in operation. There is also a 0.8 m telescope in the Santa Ynez Valley, California (BOS), which is being used for commissioning and for many local outreach programs. The first 1.0 m telescopes will be heading to Chile and South Africa in 2011 and will each be accompanied by a 0.4 m telescope. Other sites, including Tenerife (Canary Islands, Spain), McDonald Observatory (Texas), Siding Spring (Australia), and Haleakala (Hawaii) will follow, with the possibility of up to two additional sites yet to be selected. The LCOGT education and public outreach effort is transforming into a "Citizen Science" program. Several projects will encompass taking observations through the network, analyzing the data, and sharing the results with other citizen scientists from around the world. The first of these projects, "Agent Exoplanet," will be launched in mid-2011, and will involve analyzing brand-new data to create a light curve of an exoplanet. As the network is not yet complete, this test project will not include actual observing as future ones will. More information about LCOGT and its Citizen Science program can be found online (http://www.lcogt.net). In addition to material to get started in the Citizen Science program, the website also includes resources and content for more hands-on activities using archived data, general astronomy pages, network information, complete access to the public data archive, current news, and recent publications. And don't forget to

  15. Archaeological Sites Inventory of the Training Area 10 and 12 Portions of the Pinon Canyon Maneuver Site, Las Animas County, Colorado. Volume 1

    DTIC Science & Technology

    2004-01-01

    Las Cruces, New Mexico Fort Carson Cultural Resources Management Series 17S Contribution Number 10 This project was prepared for and funded by the...National Park Service, Lincoln, Nebraska Cooperative Agreement No. 1443-CA-6000-98-016 Prepared by The Department of Sociology and Anthropology New Mexico ...State University Las Cruces, New Mexico NATIONALS IL WE Fort Carson Cultural Resources Management Series Contribution Number 10 This project was

  16. Anionic surfactant linear alkylbenzene sulfonates (LAS) in sediments from the Gulf of Gdańsk (southern Baltic Sea, Poland) and its environmental implications.

    PubMed

    Hampel, Miriam; Mauffret, Aourell; Pazdro, Ksenia; Blasco, Julian

    2012-10-01

    Linear alkylbenzene sulfonate (LAS) is a group of anionic surfactants employed in the formulation of laundry and cleaning products, with a global production rate of 4 million metric tons. Sediments from the Polish coast of the southern Baltic Sea were collected at ten stations. Total LAS concentrations, measured by high-performance liquid chromatography, were between 0.04 and 0.72 mg LAS·kg(-1) dry weight. Highest LAS concentrations were found in suspended matter collected from the Vistula River, sediment collected close to the Vistula River mouth and from the Gdańsk Deep, known as the depositional area. With the obtained environmental LAS concentrations, a risk assessment for this surfactant has been carried out, based on publicly available acute and chronic toxicity data in target organisms. The results indicated that LAS could pose a low risk for the existing benthic community applying worst case scenario assessment. This is the first time that levels of LAS have been measured in environmental samples of the southern Baltic Sea.

  17. Morphology and mechanics of large collapses: Sotano de las Golondrinas, Mexico

    NASA Astrophysics Data System (ADS)

    Lauritzen, S.-E.; Hammer, Ø.; Wheeler, W.; Redfield, T.; Blanco, M.; Rosales Lagarde, L.; Jamtveit, B.

    2012-04-01

    The dynamics and mode of formation of large karst pipes are not yet fully understood. We present precise Lidar and structural field data of the 340+ m deep open karst shaft el Sotano de las Golondrinas, and test the geometry on a a simplified 2D evolution model. The Golondrinas shaft is located in the San Luis county, northeastern México and is developed in massive, early cretaceous (Barremian-Coniacian) reef- limestones (El Abra/ El Doctor fm.). It is a bell-shaped breakout dome that has reached the land surface, i.e. a classical Einstrurtzdoline. The dimensions and shape makes it to an interesting case study, as it has similar dimensions as breccia-pipes encountered in many paleokarsts, but is incompletely filled, so that internal structure can be easily inspected. Second, with regard to stress mechanisms controlling roof collapse, the large dimensions (270 - 130 m diameter at the base) reduce the influence (anisotropy) of geological structures in comparison to smaller pipes (e.g. <70 m diameter). We may thus test morphology against the shape of various tectonic and gravitational stress distributions. During our field campaign in 2009, it was decided to re-map the cavity using laser (Lidar and rangefinders) in order to obtain exact dimensions and high-resolution images of morphology and geologic structure. The maximum explored depth is a fissure at -512 m with the main floor between 325 and 400 meters below the skylight entrance of 80 m diameter. Overall, the shaft is cigar-shaped and oval in outline. Its horizontal length/width ratio at floor level is about 2.31, with an azimuth of elongation of about 125 degrees true. The shaft is developed along a major, steep fracture zone (115°, true) which makes up the north wall. The fracture has no detectable off-set, in all very few faults were observed. The strike of the guiding fracture, the azimuth of elongation and the direction of the least horizontal stress direction (111°, true) coincide. Where it occurs

  18. Xenoliths of Cerro las Mercedes, Costa Rica: a Geochemical Record of Arc History?

    NASA Astrophysics Data System (ADS)

    Lindsay, F. N.; Gazel, E.; Herzberg, C. T.; Carr, M. J.; Feigenson, M. D.

    2006-12-01

    Over 70 ultramafic xenoliths, many with diameters of at least 3cm, open a window into the mantle beneath Cerro las Mercedes, Costa Rica. This quaternary vent is 70km behind the active volcanic front and near the northern boundary of the Caribbean Plateau. Both xenoliths and host lava remain well preserved in spite of substantial soil development in a rain forest environment. We analyzed the host lava and a subset of 30 rocks for bulk and mineral chemistry, which include both peridotite and pyroxenite populations. The host rock is Plio-Quaternary potassic alkaline basalt; depleted in SiO2 and Al2O3 and enriched in MgO and P2O5 relative to both present day and Miocene volcanics. In terms of trace elements, the host basalt has enriched LREEs and relative depletion of HFSEs, typical of island-arc basalt, both present and past. The coarse-grained pyroxenites have trace element chemistry akin to the volcanic front lavas of Costa Rica, although they are closer to chondritic values. Truly, they are more similar to basalts from Sarapiquí Miocene arc than to present day volcanic front basalts. Although there is enrichment in incompatible elements such as Ba and U and depletions in HFSEs, common in island arc basalts, the pyroxenites have a strong positive Pb anomaly that is characteristic only of the Miocene arc, not present day lavas. We interpret the pyroxenites as cumulates. The peridotite population includes dunites, spinel lherzolites and lherzolites. These rocks have Mg-numbers ranging from 87 to 92 and Cr-numbers ranging from 6 to 61. Whole rock geochemistry indicates that the peridotite xenoliths are fragments of mantle associated with the western Caribbean Plateau. SiO2, FeO, Al2O3 and MgO contents of several Cerro Mercedes peridotites are similar to those expected of hot residues that would form in a plume environment. Trace elements reveal some samples with enrichment of Ba and U, and depletion in Nb and Ta indicating variable extents of melt-rock reaction and

  19. Laser Remote Measurements of atmospheric pollutants (Las-R-Map): UV-Visible Laser system description and data processing

    NASA Astrophysics Data System (ADS)

    Sivakumar, V.; Wyk, H. V.

    Laser radar more popularly known as LIDAR LIght Detection And Ranging is becoming one of the most powerful techniques for active remote sensing of the earth s atmosphere Around the globe several new lidar systems have been developed based on the scientific interest Particularly the DIfferential Absorption Lidar DIAL technique is only one which can provide the better accuracy of measuring atmospheric pollutants Using modern advanced techniques and instrumentation a mobile DIAL system called laser remote measurements of atmospheric pollutants hear after referred as Las-R-Map is designed at National Laser Centre NLC --Pretoria 25 r 45 prime S 28 r 17 prime E Las-R-Map is basically used for measuring atmospheric pollutants applying the principle of absorption by constituents The system designed primarily to focus on the following pollutant measurements such as SO 2 CH 4 CO 2 NO 2 and O 3 In future the system could be used to measure few particulate matter between 2 5 mu m and 10 mu m Benzene Hg 1 3-butadiene H 2 S HF and Volatile Organic Compounds VOC Las-R-map comprises of two different laser sources Alexandrite and CO 2 optical receiver data acquisition and signal processor It uses alexandrite laser in the UV-Visible region from 200 nm to 800 nm and CO 2 laser in the Far-IR region from 9 2 mu m to 10 8 mu m Such two different laser sources make feasibility for studying the wide range of atmospheric pollutants The present paper is focused on technical details

  20. Distress in the Desert: Neighborhood Disorder, Resident Satisfaction, and Quality of Life during the Las Vegas Foreclosure Crisis.

    PubMed

    Batson, Christie D; Monnat, Shannon M

    2015-03-01

    Using surveys collected from a sample of households nested within 'naturally occurring' neighborhoods in Las Vegas, NV during the 2007-2009 economic recession, this study examines the associations between real and perceived measures of neighborhood distress (foreclosure rate, physical decay, crime) and residents' reports of neighborhood quality of life and neighborhood satisfaction. Consistent with social disorganization theory, both real and perceived measures of neighborhood disorder were negatively associated with quality of life and neighborhood satisfaction. Residents' perceptions of neighborliness partially acted as a buffer against the effects of neighborhood distress, including housing foreclosures, on quality of life and neighborhood satisfaction.

  1. Hydrostratigraphic Framework of the Raton, Vermejo, and Trinidad Aquifers in the Raton Basin, Las Animas County, Colorado

    USGS Publications Warehouse

    Watts, Kenneth R.

    2006-01-01

    Exploration for and production of coalbed methane has increased substantially in the Rocky Mountain region of the United States since the 1990s. During 1999-2004, annual production of natural gas (coalbed methane) from the Raton Basin in Las Animas County, Colorado, increased from 28,129,515 to 80,224,130 thousand cubic feet, and the annual volume of ground water coproduced by coalbed methane wells increased from about 949 million gallons to about 2,879 million gallons. Better definition of the hydrostratigraphic framework of the Raton, Vermejo, and Trinidad aquifers in the Raton Basin of southern Colorado is needed to evaluate the long-term effects of coalbed methane development on the availability and sustainability of ground-water resources. In 2001, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study to evaluate the hydrogeology of the Raton Basin in Huerfano and Las Animas Counties, Colorado. Geostatistical methods were used to map the altitude of and depths to the bottoms and tops (structure) and the apparent thicknesses of the Trinidad Sandstone, the Vermejo Formation, and the Raton Formation in Las Animas County, based on completion reports and drillers' logs from about 1,400 coalbed methane wells in the Raton Basin. There was not enough subsurface control to map the structural surfaces and apparent thicknesses of the aquifers in Huerfano County. Geostatistical methods also were used to map the regional water table in the northern part of Las Animas County, based on reported depth to water from completion reports of water-supply wells. Although these maps were developed to better define the hydrostratigraphic framework, they also can be used to determine the contributing aquifer(s) of existing water wells and to estimate drilling depths of proposed water wells. These maps of the hydrostratigraphic framework could be improved with the addition of measured sections and mapping of geologic contacts at outcrops

  2. Las líneas de aluminio neutro como diagnóstico cromosférico

    NASA Astrophysics Data System (ADS)

    Fernández Borda, R.; Mauas, P. J. D.

    Se presenta un modelo atómico para el cálculo de las lí neas del Aluminio neutro que se forman en la cromósfera solar. En particular, se estudia la línea λ 3961 Å, que, por estar muy próxima a la lí nea H del Ca II y a Hɛ es muy frecuentemente observada. Observaciones en esta lí nea obtenidas con el espectrógrafo a instalarse en el CASLEO, serán utilizadas para el estudio de fulguraciones solares.

  3. Algorithms and Software for Solving Coupled Discrete-Time Riccati Equations Via the L-A-S Language.

    DTIC Science & Technology

    1986-08-01

    1982 . 7THESIS Submitted in partial fulfillment of the requirements 4 for the degree of Doctor of Philosophy in Electrical Engineering in the Graduate...TIME RICCATI EQUATIONS VIA THE L-A-S LANGUAGE Phillip James West, Ph.D. Department of Electrical and Computer Engineering University of Illinois at...the proof may be found in Appendix B. Theorem 3.2 : Lipschitz Constants for the Feedbacks Given(X.Y).(Z.W) E A.then IIB,(F2 (Z.W)-F(X.Y))1 2 a 2 11X-Z

  4. Distress in the Desert: Neighborhood Disorder, Resident Satisfaction, and Quality of Life during the Las Vegas Foreclosure Crisis

    PubMed Central

    Batson, Christie D.; Monnat, Shannon M.

    2014-01-01

    Using surveys collected from a sample of households nested within ‘naturally occurring’ neighborhoods in Las Vegas, NV during the 2007-2009 economic recession, this study examines the associations between real and perceived measures of neighborhood distress (foreclosure rate, physical decay, crime) and residents' reports of neighborhood quality of life and neighborhood satisfaction. Consistent with social disorganization theory, both real and perceived measures of neighborhood disorder were negatively associated with quality of life and neighborhood satisfaction. Residents' perceptions of neighborliness partially acted as a buffer against the effects of neighborhood distress, including housing foreclosures, on quality of life and neighborhood satisfaction. PMID:25750507

  5. Hacia el consumo informado de tabaco en México: efecto de las advertencias con pictogramas en población fumadora

    PubMed Central

    Thrasher, James F; Pérez-Hernández, Rosaura; Arillo-Santillán, Edna; Barrientos-Gutiérrez, Inti

    2015-01-01

    Resumen Objetivo Evaluar el efecto de las advertencias sanitarias (AS) con pictogramas en las cajetillas de tabaco en adultos fumadores. Material y métodos Cohorte de fumadores con representatividad poblacional de siete ciudades mexi canas, antes (2010) y después (2011) de la implementación de AS con pictogramas (ASP). Para determinar el cambio en las variables sobre el impacto cognitivo y conductual de las advertencias, se estimaron modelos bivariados y ajustados de ecuaciones de estimación generalizada. En el Segundo levantamiento (2011), se estimaron modelos para determiner los factores que se asocian con el reporte de recordar cada advertencia que había entrado al mercado, además de los factores asociados con el autorreporte del impacto de cada advertencia vigente. Resultados Se observaron incrementos importantes de 2010 a 2011 en los conocimientos sobre los riesgos de fumar, los componentes tóxicos del tabaco y el número telefónico para recibir consejos sobre dejar de fumar. La recordación e impacto de las primeras advertencias con pictogramas parecen ser amplios y equitativos a través de la población fumadora. En comparación con 2010, un mayor nivel de ex fumadores entrevistados en 2011 reportaron que las advertencias habían influido mucho en dejar de fumar (RM=2.44, 95% IC 1.27–4.72). Conclusiones Las AS con pictogramas han logrado un impacto importante en el conocimiento y conducta, información relevante para la población y en tomadores de decisiones. PMID:22689162

  6. Subsurface Connections and Magma Mixing as revealed by Olivine- and Pyroxene-Hosted Melt Inclusions from Cerro Negro Volcano and the Las Pilas-El Hoyo Complex, Nicaragua.

    NASA Astrophysics Data System (ADS)

    Venugopal, S.; Moune, S.; Williams-Jones, G.

    2015-12-01

    Cerro Negro, the youngest volcano in the Central American Volcanic Belt, is a polygenetic cinder cone with relatively frequent explosive basaltic eruptions. Las Pilas, on the other hand, is a much larger and older complex with milder and less frequent eruptions. Based on historical data, these two closely spaced volcanoes have shown concurrent eruptive behavior, suggesting a subsurface connection. To further investigate this link, melt inclusions, which are blebs of melt trapped in growing crystals, were the obvious choice for optimal comparison of sources and determination of pre-eruptive volatile contents and magmatic conditions. Olivine-hosted inclusions were chosen for both volcanoes and pyroxene-hosted inclusions were also sampled from Las Pilas to represent the evolved melt. Major, volatile and trace elements reveal a distinct geochemical continuum with Cerro Negro defining the primitive end member and Las Pilas representing the evolved end member. Volatile contents are high for Cerro Negro (up to 1260 ppm CO2, 4.27 wt% H2O and 1700 ppm S) suggesting that volatile exsolution is likely the trigger for Cerro Negro's explosive eruptions. Las Pilas volatile contents are lower but consistent with degassing and evolutionary trends shown by major oxides. Trace element contents are rather unique and suggest Cerro Negro magmas fractionally crystallize while Las Pilas magmas are the products of mixing. Magmatic conditions were estimated with major and volatile contents: at least 2.4 kbar and 1170 °C for Cerro Negro melts and 1.3 kbar and 1130 °C for Las Pilas melts with an overall oxygen fugacity at the NNO buffer. In combination with available literature data, this study suggests an interconnected subsurface plumbing system and thus Cerro Negro should be considered as the newest vent within the Las Pilas-El Hoyo Complex.

  7. Novel inhibitors of the Pseudomonas aeruginosa virulence factor LasB: a potential therapeutic approach for the attenuation of virulence mechanisms in pseudomonal infection.

    PubMed

    Cathcart, George R A; Quinn, Derek; Greer, Brett; Harriott, Pat; Lynas, John F; Gilmore, Brendan F; Walker, Brian

    2011-06-01

    Pseudomonas elastase (LasB), a metalloprotease virulence factor, is known to play a pivotal role in pseudomonal infection. LasB is secreted at the site of infection, where it exerts a proteolytic action that spans from broad tissue destruction to subtle action on components of the host immune system. The former enhances invasiveness by liberating nutrients for continued growth, while the latter exerts an immunomodulatory effect, manipulating the normal immune response. In addition to the extracellular effects of secreted LasB, it also acts within the bacterial cell to trigger the intracellular pathway that initiates growth as a bacterial biofilm. The key role of LasB in pseudomonal virulence makes it a potential target for the development of an inhibitor as an antimicrobial agent. The concept of inhibition of virulence is a recently established antimicrobial strategy, and such agents have been termed "second-generation" antibiotics. This approach holds promise in that it seeks to attenuate virulence processes without bactericidal action and, hence, without selection pressure for the emergence of resistant strains. A potent inhibitor of LasB, N-mercaptoacetyl-Phe-Tyr-amide (K(i) = 41 nM) has been developed, and its ability to block these virulence processes has been assessed. It has been demonstrated that thes compound can completely block the action of LasB on protein targets that are instrumental in biofilm formation and immunomodulation. The novel LasB inhibitor has also been employed in bacterial-cell-based assays, to reduce the growth of pseudomonal biofilms, and to eradicate biofilm completely when used in combination with conventional antibiotics.

  8. Equilibrium partitioning theory to predict the sediment toxicity of the anionic surfactant C(12)-2-LAS to Corophium volutator.

    PubMed

    Rico-Rico, Angeles; Temara, Ali; Hermens, Joop L M

    2009-02-01

    The study of the effect of the sorption of linear alkylbenzene sulfonates (LAS) on the bioavailability to marine benthic organisms is essential to refine the environmental risk assessment of these compounds. According to the equilibrium partitioning theory (EqP), the effect concentration in water-only exposure will be similar to the effect concentration in the sediment pore water. In this work, sorption and desorption experiments with two marine sediments were carried out using the compound C(12)-2-LAS. The effect of the sediment sorption on the toxicity of benthic organisms was studied in water-only and in sediment bioassays with the marine mud shrimp Corophium volutator. In addition, three common spiking methods were tested for its application in the toxicity tests, as well as the stability of the surfactant during the water-only and sediment-water test duration. LC50 values obtained from water-only exposure showed a good correspondence with the pore water concentrations calculated from the sorption and desorption isotherms in the spiked sediments.

  9. Long-term assessment of the oil spill at Bahia Las Minas, Panama. Interim report. Volume 1: Executive summary

    SciTech Connect

    Keller, B.D.; Jackson, J.B.C.

    1991-10-01

    On April 27, 1986, at least 8 million liters of medium-weight crude oil spilled from a ruptured storage tank into the Bahia Las Minas on the Caribbean Coast of Panama. Coral reefs, seagrass communities, and mangroves were affected. The area of the spill was also the location of the Smithsonian Tropical Research Institute's Galeta Laboratory where resident and visiting scientists have been studying the ecology of the Bahia Las Minas and the adjacent areas for over 15 years. Because this was a unique opportunity to assess the immediate biological effects following a major spill in the Caribbean region and to monitor the subsequent recovery, the U.S. Department of the Interior Minerals Management Service supported a 5-year environmental study. The objectives of the study are to identify any long-term changes in the marine environment that may have resulted from the spill and to understand the ecological processes causing such changes. This is the first report from the study and addresses the effects observed during the first two years of the effort.

  10. Long-term assessment of the oil spill at Bahia Las Minas, Panama. Interim report. Volume 2: Technical report

    SciTech Connect

    Keller, B.D.; Jackson, J.B.C.

    1991-10-01

    On April 27, 1986, at least 8 million liters of medium-weight crude oil spilled from a ruptured storage tank into the Bahia Las Minas on the Caribbean Coast of Panama. Coral reefs, seagrass communities, and mangroves were affected. The area of the spill was also the location of the Smithsonian Tropical Research Institute's Galeta Laboratory where resident and visiting scientists have been studying the ecology of the Bahia Las Minas and the adjacent areas for over 15 years. Because this was a unique opportunity to assess the immediate biological effects following a major spill in the Caribbean region and to monitor the subsequent recovery, the U.S. Department of the Interior Minerals Management Service supported a 5-year environmental study. The objectives of the study are to identify any long-term changes in the marine environment that may have resulted from the spill and to understand the ecological processes causing such changes. This is the first report from the study and addresses the effects observed during the first two years of the effort.

  11. An analysis of urban thermal characteristics and associated land cover in Tampa Bay and Las Vegas using Landsat satellite data

    USGS Publications Warehouse

    Xian, George; Crane, Mike

    2006-01-01

    Remote sensing data from both Landsat 5 and Landsat 7 systems were utilized to assess urban area thermal characteristics in Tampa Bay watershed of west-central Florida, and the Las Vegas valley of southern Nevada. To quantitatively determine urban land use extents and development densities, sub-pixel impervious surface areas were mapped for both areas. The urban–rural boundaries and urban development densities were defined by selecting certain imperviousness threshold values and Landsat thermal bands were used to investigate urban surface thermal patterns. Analysis results suggest that urban surface thermal characteristics and patterns can be identified through qualitatively based urban land use and development density data. Results show the urban area of the Tampa Bay watershed has a daytime heating effect (heat-source), whereas the urban surface in Las Vegas has a daytime cooling effect (heat-sink). These thermal effects strongly correlated with urban development densities where higher percent imperviousness is usually associated with higher surface temperature. Using vegetation canopy coverage information, the spatial and temporal distributions of urban impervious surface and associated thermal characteristics are demonstrated to be very useful sources in quantifying urban land use, development intensity, and urban thermal patterns.

  12. Source study and tectonic implications of the historic 1958 Las Melosas crustal earthquake, Chile, compared to earthquake damage

    NASA Astrophysics Data System (ADS)

    Alvarado, Patricia; Barrientos, Sergio; Saez, Mauro; Astroza, Maximiliano; Beck, Susan

    2009-06-01

    The 4 September 1958 earthquake has been the largest event recorded at shallow depths in the western flank of the Andes on Chilean territory. New estimates of fault orientation, depth and size have been carried out using modern techniques of body-wave modeling. Two possible fault planes solutions with right-lateral displacement on an east-west fault or left-lateral displacement on a north-south fault nucleated at 5-9 km depth produce the best fit to teleseismic recordings. A seismic moment M0 of 0.227 × 10 19 N m associated with a moment-magnitude Mw of 6.3 has been estimated with these techniques, which is a more reliable estimation of earthquake size than the 0.4-0.7 units larger surface-wave magnitude Ms earlier reported. Although no surface rupture for the 1958 Las Melosas crustal earthquake was reported, the displacement along east-west structures like that one suggested for one of the fault plane in our focal mechanism solution seems to be an efficient mechanism to accommodate differences in shortening from north to south in the High Andean Cordillera. Reports on damage, landslide effects as well as re-analysis of intensities associated with the new seismic source estimations for the 1958 Las Melosas earthquake are presented to further estimate the hazard to which this zone, and others along the western foothills of the Andes, is exposed.

  13. Morphology, body proportions, and postcranial hypertrophy of a female Neandertal from the Sima de las Palomas, southeastern Spain

    PubMed Central

    Walker, Michael J.; Ortega, Jon; Parmová, Klara; López, Mariano V.; Trinkaus, Erik

    2011-01-01

    Considerations of Neandertal geographical variation have been hampered by the dearth of remains from Mediterranean Europe and the absence there of sufficiently complete associated postcrania. The 2006 and 2007 excavation of an articulated partial skeleton of a small adult female Neandertal at the Sima de las Palomas, Murcia, southeastern Spain (Sima de las Palomas 96) provides substantial and secure information on body proportions among southern European Neandertals, as well as further documenting the nature of Neandertal biology in southern Iberia. The remains exhibit a suite of cranial, mandibular, dental, and postcranial features, of both Neandertals and archaic Homo generally, that distinguish them from contemporary and subsequent early modern humans. Its lower limbs exhibit the robustness of later Pleistocene Homo generally, and its upper limbs conform to the pattern of elevated robustness of the Neandertals. Its body proportions, including relative clavicular length, distal limb segment lengths, and body mass to stature indicators, conform to the “cold-adapted” pattern of more northern Neandertals. Palomas 96 therefore documents the presence of a suite of “Neandertal” characteristics in southern Iberia and, along with its small body size, the more “Arctic” body proportions of other European Neandertals despite the warmer climate of southern Iberia during marine isotope stage 3. PMID:21646528

  14. Morphology, body proportions, and postcranial hypertrophy of a female Neandertal from the Sima de las Palomas, southeastern Spain.

    PubMed

    Walker, Michael J; Ortega, Jon; Parmová, Klara; López, Mariano V; Trinkaus, Erik

    2011-06-21

    Considerations of Neandertal geographical variation have been hampered by the dearth of remains from Mediterranean Europe and the absence there of sufficiently complete associated postcrania. The 2006 and 2007 excavation of an articulated partial skeleton of a small adult female Neandertal at the Sima de las Palomas, Murcia, southeastern Spain (Sima de las Palomas 96) provides substantial and secure information on body proportions among southern European Neandertals, as well as further documenting the nature of Neandertal biology in southern Iberia. The remains exhibit a suite of cranial, mandibular, dental, and postcranial features, of both Neandertals and archaic Homo generally, that distinguish them from contemporary and subsequent early modern humans. Its lower limbs exhibit the robustness of later Pleistocene Homo generally, and its upper limbs conform to the pattern of elevated robustness of the Neandertals. Its body proportions, including relative clavicular length, distal limb segment lengths, and body mass to stature indicators, conform to the "cold-adapted" pattern of more northern Neandertals. Palomas 96 therefore documents the presence of a suite of "Neandertal" characteristics in southern Iberia and, along with its small body size, the more "Arctic" body proportions of other European Neandertals despite the warmer climate of southern Iberia during marine isotope stage 3.

  15. An evaluation of lead contamination in plastic toys collected from day care centers in the Las Vegas Valley, Nevada, USA.

    PubMed

    Greenway, Joseph A; Gerstenberger, Shawn

    2010-10-01

    Childhood exposure to environmental lead continues to be a major health concern. This study examined lead content within the plastic of children's toys collected from licensed day care centers in the Las Vegas valley, Nevada. It was hypothesized that the use of lead as a plastics stabilizer would result in elevated lead (≥600 ppm) in polyvinyl chloride plastics (PVC) compared to non-PVC plastics. It was also hypothesized that, due to the use of lead chromate as a coloring agent, yellow toys would contain higher concentrations of lead (≥600 ppm) than toys of other colors. Toy samples were limited to those found in day care centers in Las Vegas, Nevada. 10 day care centers were visited and approximately 50 toy samples were taken from each center. Of the 535 toys tested, 29 contained lead in excess of 600 parts per million (ppm). Of those 29 toys, 20 were PVC and 17 were yellow. Both of the two hypotheses were strongly supported by the data.

  16. 2LAs, 3LAs, and the enterprise

    SciTech Connect

    Hoffmann, T.

    1998-01-01

    This article is about new things that engineers, facility managers and automation system operators need to learn about and understand when it comes to integrating information throughout an enterprise. The goal is to help one better understand the connection between building systems and building intelligence. The authors set the foundation with an overview of the latest concept in network communications, enterprise computing. Because any new technology spawns a number of acronyms, they`ll also investigate new two-, three-, four- and five-letter acronyms that directly affect the changing role of the building automation system (BAS) as it becomes an integral, contributing part of the business. In each case, one or more Internet URLs will be provided for more information.

  17. A new method for the routine analysis of LAS and PAH in sewage sludge by simultaneous sonication-assisted extraction prior to liquid chromatographic determination.

    PubMed

    Santos, J L; Aparicio, I; Alonso, E

    2007-12-12

    Linear alkylbenzene sulphonates (LAS) and polycyclic aromatics hydrocarbons (PAH) are organic pollutants in sewage sludge which will have to be monitored in the European Union according to the third draft of a future sludge directive. In the present work, an analytical method for the simultaneous extraction of 4 LAS homologues and 16 PAH congeners in sludge from wastewater treatment plants is proposed to improve the routine analysis of these compounds in sludge samples. The method involves sonication assisted extraction, clean-up and preconcentration by solid phase extraction, and determination by high-performance liquid chromatography with ultraviolet diode array (UV-DAD) and fluorescence (FLD) detectors. Average recoveries were 87% for LAS and 76% for PAH, with relative standard deviations below 13%. Limits of quantification of LAS and PAH were in the range from 13 to 56 mg kg(-1) and from 80 to 650 microg kg(-1), respectively, when using UV-DAD. Limits of quantification of LAS and PAH were in the range 5-18 mg kg(-1) and from 1 to 150 microg kg(-1), respectively, when using FLD. The applicability of the proposed method was evaluated by the determination of these compounds in sludge from wastewater treatment plants in Seville (South Spain).

  18. Establishment and characterization of a novel lymphangiosarcoma cell line (MO-LAS) compared with the hemangiosarcoma cell line (ISO-HAS).

    PubMed

    Masuzawa, Mikio; Masuzawa, Mamiko; Hamada, Yuhko; Arakawa, Nobuko; Mori, Mari; Ishii, Masako; Nishiyama, Shigeo

    2012-08-01

    The concept of "lymphangiosarcoma" remains obscure. Therefore, we reported a patient with lymphangiosarcoma, resistant to immunotherapy. The patient presented with impressive and discriminative features: clinically an ill-defined edematous lesion with lymphorrhea and pathologically atypical vascular channel formation without extravasation of blood, clearly distinguished from common angiosarcoma with hemorrhage. From this case, a lymphangiosarcoma cell line, MO-LAS, was established and its characteristics were compared with the hemangiosarcoma cell line, ISO-HAS. Flow cytometric analysis revealed that MO-LAS was negative for factor VIII-related antigen, but positive for CD31, D2-40, NZ-1, and vascular endothelial growth factor receptor-3 (VEGFR-3), similar to ISO-HAS. However, MO-LAS expressed a much higher level of homeobox gene PROX1, indicating a lymphatic phenotype, compared with ISO-HAS. Furthermore, MO-LAS showed a much lesser expression of oncogenes and much lower sensitivity against lymphokine-activated killer (LAK) cells. Lymphangiosarcoma may be difficult to recognize by the immune system. Conclusively, the establishment of MO-LAS, a novel angiosarcoma cell line bearing lymphatic characters, strongly suggests the entity of lymphangiosarcoma.

  19. [Effects and mechanisms of inorganic anions in water on degradation of LAS by UV/H2 O2 combination process].

    PubMed

    Pan, Jing; Sun, Tie-Heng; Li, Hai-Bo

    2007-11-01

    Experiments are carried out to study the effects and mechanisms of inorganic anions in water on the degradation of linear alkyl benzene sulfonate (LAS) in UV/H2 O2 process. The results show that UV/H2 O2 process could remove LAS effectively, and the rate of photodegradation follows first-order reaction kinetics model. Under the condition that H2 O2 concentration was 8 mg x L(-1) and a 14 W low pressure mercury vapor discharge lamp irradiated samples, the first-order photodegradation rate constant of LAS in distilled water and tap water were 0.018 0 min(-1) and 0.012 2 min(-1) respectively. NO3-, Cl-, SO4(2-) and HCO3- have inhibitory action on LAS photodegradation. The higher inorganic anions concentration was, the stronger inhibitory action. When their concentrations were 5, 10 and 15 mmol x L(-1) respectively, their inhibitory action order was HCO3- > NO3- > Cl- > SO4(2-) all the time. It was anions synthetical effect that caused photodegradation rate constant of LAS in tap water lower than distilled water.

  20. Water-quality data for the Rio Grande between Picacho Bridge near Las Cruces and Calle del Norte Bridge near Mesilla, New Mexico, 1996-97

    USGS Publications Warehouse

    Huff, G.F.

    1998-01-01

    The City of Las Cruces is concerned about water quality in a reach of the Rio Grande that receives outfall from the City of Las Cruces wastewater-treatment plant. Water-quality samples were collected from the Rio Grande at Picacho Bridge near Las Cruces, New Mexico; from the sampling site at the City of Las Cruces wastewater-treatment plant; and from the Rio Grande at Calle del Norte Bridge near Mesilla, New Mexico. The samples were collected on 12 days from August 6, 1996, to February 28, 1997, and were analyzed for a suite of dissolved and total constituents including trace metals. Instantaneous stream discharge was measured concurrently with collection of the Rio Grande samples. At the wastewater- treatment plant, the City of Las Cruces provided instantaneous discharge rates concurrent with sampling. Quality-control measures used in this study to ensure analytical accuracy included replicate sampling, replicate analysis of split samples, ambient blanks, equipment blanks, and analysis of standard reference water samples.

  1. Log ASCII Standard (LAS) Files for Geophysical Wireline Well Logs and Their Application to Geologic Cross Sections Through the Central Appalachian Basin

    USGS Publications Warehouse

    Crangle, Robert D.

    2007-01-01

    Introduction The U.S. Geological Survey (USGS) uses geophysical wireline well logs for a variety of purposes, including stratigraphic correlation (Hettinger, 2001, Ryder, 2002), petroleum reservoir analyses (Nelson and Bird, 2005), aquifer studies (Balch, 1988), and synthetic seismic profiles (Kulander and Ryder, 2005). Commonly, well logs are easier to visualize, manipulate, and interpret when available in a digital format. In recent geologic cross sections E-E' and D-D', constructed through the central Appalachian basin (Ryder, Swezey, and others, in press; Ryder, Crangle, and others, in press), gamma ray well log traces and lithologic logs were used to correlate key stratigraphic intervals (Fig. 1). The stratigraphy and structure of the cross sections are illustrated through the use of graphical software applications (e.g., Adobe Illustrator). The gamma ray traces were digitized in Neuralog (proprietary software) from paper well logs and converted to a Log ASCII Standard (LAS) format. Once converted, the LAS files were transformed to images through an LAS-reader application (e.g., GeoGraphix Prizm) and then overlain in positions adjacent to well locations, used for stratigraphic control, on each cross section. This report summarizes the procedures used to convert paper logs to a digital LAS format using a third-party software application, Neuralog. Included in this report are LAS files for sixteen wells used in geologic cross section E-E' (Table 1) and thirteen wells used in geologic cross section D-D' (Table 2).

  2. Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Miranda, G. P.; Gaffney, J. S.; Marley, N. A.

    2007-05-01

    Four photoacoustic spectrometers (PAS) for aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The four sites included: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP); a suburban site at the Technological University of Tecamac; a rural site at "La Biznaga" ranch; and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. A similar campaign was held in Las Vegas, Nevada, USA in January-February, 2003. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. Comparisons with TSI nephelometer scattering at the T0 site will be presented. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of

  3. Changes in air quality at near-roadway schools after a major freeway expansion in Las Vegas, Nevada.

    PubMed

    Brown, Steven G; McCarthy, Michael C; DeWinter, Jennifer L; Vaughn, David L; Roberts, Paul T

    2014-09-01

    Near-roadway ambient black carbon (BC) and carbon monoxide (CO) concentrations were measured at two schools adjacent to a freeway and at an urban background school 2 km from the freeway to determine the change in concentrations attributable to vehicle emissions after the three-lane expansion of U.S. Highway 95 (US 95) in Las Vegas, Nevada. Between summer 2007 and summer 2008, average weekday small-vehicle volume increased by 40% +/- 2% (standard error). Average weekday large-vehicle volume decreased by 17% +/- 5%, due to a downturn in the economy and an associated decline in goods movement. Average vehicle speed increased from 58 to 69 mph, a 16% +/- 1% increase. The authors compared BC and CO concentrations in summer 2007 with those in summer 2008 to understand what effect the expansion of the freeway may have had on ambient concentrations: BC and CO were measured 17 m north of the freeway sound wall, CO was measured 20 m south of the sound wall, and BC was measured at an urban background site 2 km south of the freeway. Between summer 2007 and summer 2008, median BC decreased at the near-road site by 40% +/- 2% and also decreased at the urban background site by 24% +/- 4%, suggesting that much of the change was due to decreases in emissions throughout Las Vegas, rather than only on US 95. CO concentrations decreased by 14% +/- 2% and 10% +/- 3% at the two near-road sites. The decrease in BC concentrations after the expansion is likely due to the decrease in medium- and heavy-duty-vehicle traffic resulting from the economic recession. The decrease in CO concentrations may be a result of improved traffic flow, despite the increase in light-duty-vehicle traffic. Implications: Monitoring of BC and CO at near-road locations in Las Vegas demonstrated the impacts of changes in traffic volume and vehicle speed on near-road concentrations. However, urban-scale declines in concentrations were larger than near-road changes due to the impacts of the economic recession that

  4. Informe sobre el avance del proyecto de determinaciones de V sen i para todas las estrellas B más brillantes que 6.5 mag.

    NASA Astrophysics Data System (ADS)

    Abt, H.; Levato, H.

    Se ha finalizado con la determinación de V sen i para todas las estrellas B más brillantes que 6.5 mag y al norte de -30 grados de declinación. Esta muestra involucra casi 1000 estrellas. Las observaciones fueron realizadas desde KPNO. Mientras tanto, se ha completado desde CASLEO la observación de 350 estrellas B más brillantes que 6.5 mag. al sur de -30 grados. Además de la determinación de la rotación axial se determinan, en los casos posibles, los anchos equivalentes de las líneas 4471 Ådel He I y 4481 Ådel Mg II.

  5. Log ASCII Standard (LAS) Files for Geophysical (Gamma Ray) Wireline Well Logs and Their Application to Geologic Cross Section C-C' Through the Central Appalachian Basin

    USGS Publications Warehouse

    Trippi, Michael H.; Crangle, Robert D.

    2009-01-01

    U.S. Geological Survey (USGS) regional geologic cross section C-C' (Ryder and others, 2008) displays key stratigraphic intervals in the central Appalachian basin. For this cross section, strata were correlated by using descriptions of well cuttings and gamma ray well log traces. This report summarizes the procedures used to convert gamma ray curves on paper well logs to the digital Log ASCII (American Standard Code for Information Interchange) Standard (LAS) format using the third-party software application Neuralog. The procedures could be used with other geophysical wireline logs also. The creation of digital LAS files from paper well logs by using Neuralog is very helpful, especially when dealing with older logs with limited or nonexistent digital data. The LAS files from the gamma ray logs of 11 wells used to construct cross section C-C' are included in this report. They may be downloaded from the index page as a single ZIP file.

  6. Simulation of unsaturated flow and solute transport at the Las Cruces trench site using the PORFLO-3 computer code

    SciTech Connect

    Rockhold, M.L.; Wurstner, S.K.

    1991-03-01

    The objective of this work was to test the ability of the PORFLO-3 computer code to simulate water infiltration and solute transport in dry soils. Data from a field-scale unsaturated zone flow and transport experiment, conducted near Las Cruces, New Mexico, were used for model validation. A spatial moment analysis was used to provide a quantitative basis for comparing the mean simulated and observed flow behavior. The scope of this work was limited to two-dimensional simulations of the second experiment at the Las Cruces trench site. Three simulation cases are presented. The first case represents a uniform soil profile, with homogeneous, isotropic hydraulic and transport properties. The second and third cases represent single stochastic realizations of randomly heterogeneous hydraulic conductivity fields, generated from the cumulative probability distribution of the measured data. Two-dimensional simulations produced water content changes that matched the observed data reasonably well. Models that explicitly incorporated heterogeneous hydraulic conductivity fields reproduced the characteristics of the observed data somewhat better than a uniform, homogeneous model. Improved predictions of water content changes at specific spatial locations were obtained by adjusting the soil hydraulic properties. The results of this study should only be considered a qualitative validation of the PORFLO-3 code. However, the results of this study demonstrate the importance of site-specific data for model calibration. Applications of the code for waste management and remediation activities will require site-specific data for model calibration before defensible predictions of unsaturated flow and containment transport can be made. 23 refs., 16 figs., 3 tabs.

  7. An Intensity-Modulated CW LAS System for Application to ASCENDS: Overview of Development, Testing, and Evaluation

    NASA Astrophysics Data System (ADS)

    Ismail, S.; Harrison, F. W.; Dobler, J. T.; Browell, E. V.; Nehrir, A. R.; Lin, B.; Meadows, B.; Vanek, M. D.; Kooi, S. A.; Collins, J. E.; Refaat, T. F.; Yang, M. M.; Choi, Y.; DiJoseph, M.

    2012-12-01

    As part of the development of a capability for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission NASA Langley Langley Research Center (LaRC) and ITT EXELIS are collaborating to develop and demonstrate an approach for measuring column CO2 from space. A Multi-Functional Fiber Laser Lidar (MFLL), a laser absorption spectrometer (LAS) system has been used to demonstrate high precision column CO2 measurements from aircraft platforms. MFLL operates near the 1.57 micron region using an intensity modulated CW LAS system. High precision column CO2 measurements have been demonstrated over several land and ocean surfaces under a variety of atmospheric conditions, and also demonstrated insensitivity to variations in surface reflectivity and altitude. Encoded modulation schemes have been used to minimize the influence of thin clouds on column CO2 measurements. We present examples of these measurements from past flight campaigns, and developments are presented on models to predict the precision and accuracy of these measurements as determined from ground-based range testing at LaRC during July-August 2012. We present a summary of results from testing of the MFLL from the ground using various targets at a distance of 860 m. During these tests measurements are made using well characterized ground targets, controlled background conditions, and a variety of intermediate range, partially reflecting and light attenuating targets that are used as simulants for thin clouds. A variety of modulation schemes are being tested to discriminate against cloud interferences and for evaluating precise ranging capability. Profiles of CO2, relative humidity (RH), pressure, and temperature along the range are being made to validate the CO2 column measurements. These ground-based measurements are valuable to validate models for predicting the precision and accuracy of these measurements, interpretation of measurements from aircraft by the MFLL, and projecting

  8. Systems dynamic model to forecast salinity load to the Colorado River due to urbanization within the Las Vegas Valley.

    PubMed

    Venkatesan, Arjun K; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R

    2011-06-01

    This study evaluates the impact of urban growth in the Las Vegas Valley (LVV), Nevada, USA on salinity of the Colorado River. In the past thirty eight years the LVV population has grown from 273,288 (1970) to 1,986,146 (2008). The wastewater effluents and runoff from the valley are diverted back to the Colorado River through the Las Vegas Wash (LVW). With the growth of the valley, the salinity released from urban areas has increased the level of TDS in the wastewater effluents, ultimately increasing the TDS in the Colorado River. The increased usage of water softeners in residential and commercial locations is a major contributor of TDS in the wastewater effluents. Controlling TDS release to the Colorado River is important because of the 1944 Treaty signed between the USA and Mexico. In addition, the agriculture salinity damage cost for the Colorado River has been estimated to be more than $306 a million per year using 2004 salinity levels. With the expected growth of LVV in coming years the TDS release into Lake Mead will increase over time. For this purpose, it is important to investigate future TDS release into the Colorado in anticipation of potential TDS reducing measures to be adopted. In this research, a dynamic simulation model was developed using system dynamics modeling to carry out water and TDS mass balances over the entire LVV. The dynamic model output agreed with historic data with an average error of 2%. Forecasts revealed that conservation efforts can reduce TDS load by 16% in the year 2035 when compared to the current trend. If total population using water softeners can be limited to 10% in the year 2035, from the current 30% usage, TDS load in the LVW can be reduced by 7%.

  9. Sources and concentrations of mercury and selenium in compartments within the Las Vegas Wash during a period of rapid change.

    PubMed

    Cizdziel, James; Zhou, Xiaoping

    2005-08-01

    The Las Vegas Wash, which drains the Las Vegas valley watershed and provides the second largest inflow to Lake Mead, is being dramatically altered with erosion control structures and wetland restoration efforts. The impact of these changes on the cycling and distribution of Hg and Se is of particular interest because of their tendency to bioaccumulate and because of a lack of information on these contaminants in the Wash. In this study, we determined concentrations of Hg and Se in surface water (monthly), groundwater (once) and sediments (quarterly) from strategic locations within and along the Wash during 2002 and 2003. The data was used to characterize Se sources and loading into the Wash. Samples containing resurfacing groundwater and urban runoff (LW10.75 and Duck Creek) had significantly higher yearly means (13.7 +/- 4.4 and 23.8 +/- 4.1 microg/L, respectively) compared with mainstream samples containing primarily treated wastewater (2.8 +/- 0.8 microg/L). Investigation of Se in tributaries, street runoff and rain suggest that the source of the elevated Se is likely groundwater seeps located within a relatively narrow geographic band on the southeast side of the valley. Se content of sediments was similar, except for LW10.75 which was rich in organic matter. Hg concentrations in the water and sediments were low, averaging 4 +/- 5 ng/L and 34 +/- 20 ng/g, dw, respectively. Overall, this study suggests that water quality remains relatively stable despite changes in the Wash and managers of developing wetlands should not use tributary water as source water.

  10. Heavy Metal Contamination and Salt Efflorescence Associated With Decorative Landscaping Rocks, Las Vegas, Nevada: The Need for Regulations

    NASA Astrophysics Data System (ADS)

    Mrozek, S. A.; Buck, B. J.; Brock, A. L.

    2004-12-01

    Las Vegas, Nevada is one of the fastest growing cities in the United States. Faced with water restrictions, decorative rock xeroscaping has become a very popular form of landscaping. Currently, there are no regulations controlling the geochemistry of the decorative rocks that can be used for these purposes. In this study, we examined three sites containing two different decorative rock products. The landscaping rocks, underlying soil, and surface salt crusts were analyzed to determine their mineralogy and chemistry. Methods of analysis include scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP), thin section analysis, and laser particle size analysis (LPSA). Preliminary results indicate the presence of halite (NaCl), bloedite (Na2Mg(SO4)2 4H2O), a hydrated magnesium sulfate, and possibly copper sulfate and copper chloride mineral phases in the surface salt crusts. Both copper minerals are regarded as hazardous substances by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA); these agencies have established minimum exposure limits for human contact with these substances. Copper sulfate and copper chloride are not naturally occurring minerals in the soils of the Las Vegas Valley, and analyses indicate that their formation may be attributed to the mineralogy of the decorative landscaping rocks. Further testing is needed to characterize this potential health hazard; however the preliminary results of this study demonstrate the need for regulations controlling the geochemistry of decorative rocks used for urban landscaping.

  11. A preliminary assessment of earthquake ground shaking hazard at Yucca Mountain, Nevada and implications to the Las Vegas region

    SciTech Connect

    Wong, I.G.; Green, R.K.; Sun, J.I.; Pezzopane, S.K.; Abrahamson, N.A.; Quittmeyer, R.C.

    1996-12-31

    As part of early design studies for the potential Yucca Mountain nuclear waste repository, the authors have performed a preliminary probabilistic seismic hazard analysis of ground shaking. A total of 88 Quaternary faults within 100 km of the site were considered in the hazard analysis. They were characterized in terms of their probability o being seismogenic, and their geometry, maximum earthquake magnitude, recurrence model, and slip rate. Individual faults were characterized by maximum earthquakes that ranged from moment magnitude (M{sub w}) 5.1 to 7.6. Fault slip rates ranged from a very low 0.00001 mm/yr to as much as 4 mm/yr. An areal source zone representing background earthquakes up to M{sub w} 6 1/4 = 1/4 was also included in the analysis. Recurrence for these background events was based on the 1904--1994 historical record, which contains events up to M{sub w} 5.6. Based on this analysis, the peak horizontal rock accelerations are 0.16, 0.21, 0.28, and 0.50 g for return periods of 500, 1,000, 2,000, and 10,000 years, respectively. In general, the dominant contributor to the ground shaking hazard at Yucca Mountain are background earthquakes because of the low slip rates of the Basin and Range faults. A significant effect on the probabilistic ground motions is due to the inclusion of a new attenuation relation developed specifically for earthquakes in extensional tectonic regimes. This relation gives significantly lower peak accelerations than five other predominantly California-based relations used in the analysis, possibly due to the lower stress drops of extensional earthquakes compared to California events. Because Las Vegas is located within the same tectonic regime as Yucca Mountain, the seismic sources and path and site factors affecting the seismic hazard at Yucca Mountain also have implications to Las Vegas. These implications are discussed in this paper.

  12. Reversible reduction of estrone to 17β-estradiol by Rhizobium, Sphingopyxis, and Pseudomonas isolates from the Las Vegas Wash

    USGS Publications Warehouse

    Blunt, Susanna; Benotti, Mark; Rosen, Michael R.; Hedlund, Brian; Moser, Duane

    2017-01-01

    Environmental endocrine-disrupting compounds (EDCs) are a growing concern as studies reveal their persistence and detrimental effects on wildlife. Microorganisms are known to affect the transformation of steroid EDCs; however, the diversity of estrogen-degrading microorganisms and the range of transformations they mediate remain relatively little studied. In mesocosms, low concentrations of added estrone (E1) and 17β-estradiol (E2) were removed by indigenous microorganisms from Las Vegas Wash water within 2 wk. Three bacterial isolates, Rhizobium sp. strain LVW-9, Sphingopyxis sp. strain LVW-12, and Pseudomonas sp. strain LVW-PC, were enriched from Las Vegas Wash water on E1 and E2 and used for EDC transformation studies. In the presence of alternative carbon sources, LVW-9 and LVW-12 catalyzed near-stoichiometric reduction of E1 to E2 but subsequently reoxidized E2 back to E1; whereas LVW-PC minimally reduced E1 to E2 but effectively oxidized E2 to E1 after a 20-d lag. In the absence of alternative carbon sources, LVW-12 and LVW-PC oxidized E2 to E1. This report documents the rapid and sometimes reversible microbial transformation of E1 and E2 and the slow degradation of 17α-ethinylestradiol in urban stream water and extends the list of known estrogen-transforming bacteria to the genera Rhizobium and Sphingopyxis. These results suggest that discharge of steroid estrogens via wastewater could be reduced through tighter control of redox conditions and may assist in future risk assessments detailing the environmental fate of estrogens through evidence that microbial estrogen transformations may be affected by environmental conditions or growth status.

  13. Environmental Assessment for Enhanced Use Lease of U.S. Air Force Lands to the City of North Las Vegas for Construction and Operation of a Water Reclamation Facility, Nellis Air Force Base, Nevada

    DTIC Science & Technology

    2008-01-01

    Federal Status Habitat Potential to occur within Project Area Razorback sucker Xyrauchen texanus Endangered Backwaters, sloughs, oxbow lakes , and...up to 39 per cent of water use in the valley, with the remainder coming from Lake Mead (Las Vegas Valley Water District 2008). 3.7.1 Surface Water...City of North Las Vegas North Las Vegas Water Reclamation Facility Environmental Assessment 8 Site 6 (Bay Lake Trail and Kier Road): Advantages to

  14. The influence of faults in basin-fill deposits on land subsidence, Las Vegas Valley, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Burbey, Thomas

    2002-07-01

    The role of horizontal deformation caused by pumping of confined-aquifer systems is recognized as contributing to the development of earth fissures in semiarid regions, including Las Vegas Valley, Nevada. In spite of stabilizing water levels, new earth fissures continue to develop while existing ones continue to lengthen and widen near basin-fill faults. A three-dimensional granular displacement model based on Biot's consolidation theory (Biot, MA, 1941, General theory of three-dimensional consolidation. Jour. Applied Physics 12:155-164) has been used to evaluate the nature of displacement in the vicinity of two vertical faults. The fault was simulated as (1) a low-permeability barrier to horizontal flow, (2) a gap or structural break in the medium, but where groundwater flow is not obstructed, and (3) a combination of conditions (1) and (2). Results indicate that the low-permeability barrier greatly enhances horizontal displacement. The fault plane also represents a location of significant differential vertical subsidence. Large computed strains in the vicinity of the fault may suggest high potential for failure and the development of earth fissures when the fault is assumed to have low permeability. Results using a combination of the two boundaries suggest that potential fissure development may be great at or near the fault plane and that horizontal deformation is likely to play a key role in this development. Résumé. On considère que la déformation horizontale provoquée par un pompage dans un aquifère captif joue un rôle dans le développement des fissures du sol en régions semi-arides, comme la vallée de Las Vegas (Nevada). Malgré des niveaux d'eau stabilisés, de nouvelles fissures du sol continuent de se développer en longueur et en largeur au voisinage de failles dans les bassins sédimentaires. Un modèle de déplacement granulaire tri-dimensionnel, basé sur la théorie de la consolidation de Biot (Biot, M A, 1941, General theory of three

  15. Clinical cutaneous leishmaniasis rates are associated with household Lutzomyia gomezi, Lu. Panamensis, and Lu. trapidoi abundance in Trinidad de Las Minas, western Panama.

    PubMed

    Saldaña, Azael; Chaves, Luis F; Rigg, Chystrie A; Wald, Coridalia; Smucker, Joanne E; Calzada, Jose E

    2013-03-01

    American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile.

  16. Clinical Cutaneous Leishmaniasis Rates Are Associated with Household Lutzomyia gomezi, Lu. Panamensis, and Lu. trapidoi Abundance in Trinidad de Las Minas, Western Panama

    PubMed Central

    Saldaña, Azael; Chaves, Luis F.; Rigg, Chystrie A.; Wald, Coridalia; Smucker, Joanne E.; Calzada, Jose E.

    2013-01-01

    American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile. PMID:23339202

  17. Cómo aumentar la actividad física de los niños durante el período del recreo en las escuelas

    PubMed Central

    Ludwig, David

    2014-01-01

    Objetivos. Analizamos si la participación de las escuelas en el Programa de Mejoramiento del Recreo (PMR) en la primavera del año 2011 estuvo asociada a tasas más altas de actividad física intensa en los niños. Métodos. En el PMR, un coordinador dirige a los niños para que practiquen juegos adecuados para la edad a fin de aumentar su nivel de actividad física. Durante el recreo en 25 escuelas primarias públicas de la ciudad de Nueva York (15 participantes en el PMR, 10 no participantes en el PMR) los investigadores observaron algunas áreas predeterminadas (n = 1 339 observaciones) y registraron el número de niños que estaban sedentarios, caminando o muy activos. Resultados. Tras el análisis estadístico con múltiples variables se encontró que la participación en el PMR era una variable predictiva significativa (P = 0,027) de la tasa de actividad física intensa (porcentaje de niños muy activos en las áreas de observación) cuyas medias de los mínimos cuadrados fueron de 41% en las escuelas participantes en el PMR y de 27% en escuelas no participantes en el PMR. En las escuelas participantes en el PMR se siguió registrando una tasa significativamente superior incluso cuando el coordinador de juegos no estaba en el área de observación, lo que sugiere un cambio en la cultura del recreo en las escuelas que participan en este programa. Conclusiones. La tasa de actividad física intensa en las escuelas participantes en el PMR fue 14 puntos porcentuales (o 52%) superior a la tasa registrada en las escuelas no participantes en el PMR. Esta intervención de bajo costo podría ser un agregado valioso a las herramientas para combatir la obesidad infantil y podría valer la pena reproducirla en otros sitios. PMID:24899455

  18. Evolución en el tiempo de las relaciones Masa-Luminosidad y Corrección Bolométrica y Temperatura Efectiva contra Índice de Color

    NASA Astrophysics Data System (ADS)

    Miloni, L. A.; Camperi, J. A.

    Analizamos la evolución que en los últimos 70 años han tenido las relaciones M-L, BC vs CI y Teff vs CI. Se discuten las causas de esa evolución, se trata de incorporar los valores más modernos disponibles discutiendo su calidad y se deducen las relaciones que actualmente deberían ser las más confiables. Destacamos los puntos en los que estas relaciones continúan estando pobremente definidas y sería deseable mejorar en el futuro próximo.

  19. Reproductive Responses of Common Carp Cyprinus carpio in Cages to Influent of the Las Vegas Wash in Lake Mead, Nevada, from late Winter to early Spring

    EPA Science Inventory

    To investigate the potential for contaminants in Las Vegas Wash (LW) influent to produce effects indicative of endocrine disruption in vivo, adult male and female common carp were exposed in cages for 42-48 d at four sites and two reference locations in Lake Mead.

  20. Exploring the effects of population growth on future land use change in the Las Vegas Wash watershed: an integrated approach of geospatial modeling and analytics

    EPA Science Inventory

    The Las Vegas Valley metropolitan area is one of the fastest growing areas in the southwestern United States. The rapid urbanization has led to many environmental problems. For instance, as population growth and urbanization continue, there will be a problem with water shortage. ...

  1. Long-term continuous measurement of near-road air pollution in Las Vegas: Seasonal variability in traffic emissions impact on local air quality

    EPA Science Inventory

    Excess air pollution along roadways is an issue of public health concern and motivated a long-term measurement effort established by the U.S. Environmental Protection Agency in Las Vegas, Nevada. Measurements of air pollutants – including black carbon (BC), carbon monoxide (CO),...

  2. School Resegregation in the Mississippi of the West: Community Counternarratives on the Return to Neighborhood Schools in Las Vegas, 1968-1994

    ERIC Educational Resources Information Center

    Horsford, Sonya Douglass; Sampson, Carrie; Forletta, Felicia

    2013-01-01

    Background: School desegregation and resegregation in the Mountain West remain understudied despite the substantial impact the region's growth and demographic change have had on racial balance and diversity in schools. Home to the largest school district in the Mountain West and fifth largest school district in the country, Las Vegas's…

  3. Hoja informativa: Reducción de la contaminaión de carbono de las centrales eléctricas

    EPA Pesticide Factsheets

    la EPA anunciaron el Plan de Energía Limpia; un paso histórico e importante en la reducción de la contaminación de carbono de las centrales eléctricas que toma medidas concretas respecto al cambio climático.

  4. Six month progress report on the Waste Package Project at the University of Nevada, Las Vegas, July 1991--January 1992: Management, quality assurance and overview

    SciTech Connect

    Ladkany, S.G.

    1991-12-31

    The progress of the waste package project at the University of Nevada, Las Vegas was the subject of this report. It covered aspects of management and quality assurance, container design, application of ASME Pressure Vessel Codes, structural analysis of containers, design of rock tunnels for storage, and heat transfer phenomena. (MB)

  5. Six month progress report on the Waste Package Project at the University of Nevada, Las Vegas, July 1991--January 1992: Management, quality assurance and overview

    SciTech Connect

    Ladkany, S.G.

    1991-01-01

    The progress of the waste package project at the University of Nevada, Las Vegas was the subject of this report. It covered aspects of management and quality assurance, container design, application of ASME Pressure Vessel Codes, structural analysis of containers, design of rock tunnels for storage, and heat transfer phenomena. (MB)

  6. Integrating NASA's Land Analysis System (LAS) image processing software with an appropriate Geographic Information System (GIS): A review of candidates in the public domain

    NASA Technical Reports Server (NTRS)

    Rochon, Gilbert L.

    1989-01-01

    A user requirements analysis (URA) was undertaken to determine and appropriate public domain Geographic Information System (GIS) software package for potential integration with NASA's LAS (Land Analysis System) 5.0 image processing system. The necessity for a public domain system was underscored due to the perceived need for source code access and flexibility in tailoring the GIS system to the needs of a heterogenous group of end-users, and to specific constraints imposed by LAS and its user interface, Transportable Applications Executive (TAE). Subsequently, a review was conducted of a variety of public domain GIS candidates, including GRASS 3.0, MOSS, IEMIS, and two university-based packages, IDRISI and KBGIS. The review method was a modified version of the GIS evaluation process, development by the Federal Interagency Coordinating Committee on Digital Cartography. One IEMIS-derivative product, the ALBE (AirLand Battlefield Environment) GIS, emerged as the most promising candidate for integration with LAS. IEMIS (Integrated Emergency Management Information System) was developed by the Federal Emergency Management Agency (FEMA). ALBE GIS is currently under development at the Pacific Northwest Laboratory under contract with the U.S. Army Corps of Engineers' Engineering Topographic Laboratory (ETL). Accordingly, recommendations are offered with respect to a potential LAS/ALBE GIS linkage and with respect to further system enhancements, including coordination with the development of the Spatial Analysis and Modeling System (SAMS) GIS in Goddard's IDM (Intelligent Data Management) developments in Goddard's National Space Science Data Center.

  7. Applying Alternative Teaching Methods to Impart a Rounded, Liberal Arts and Sciences (LAS) Education: Students' Reflections on the Role of Magazines as Instructional Tools

    ERIC Educational Resources Information Center

    Sithole, Alec; Kibirige, Joachim; Mupinga, Davison M.; Chiyaka, Edward T.

    2016-01-01

    In a constantly and rapidly changing social world, students from all disciplines ought to attain a rounded education within the tradition of a "Liberal Arts and Sciences" (LAS) context. Students outside of the natural sciences must be encouraged to appreciate the place of those sciences in their lives. Conversely, students in the natural…

  8. Full House: The Las Vegas building boom has stretched the creativity and resources of the fastest-growing school district in the nation. Edutopia, September/October 2004

    ERIC Educational Resources Information Center

    Furger, Roberta

    2004-01-01

    This once sleepy community, founded by Mormon missionaries in 1855 and jumpstarted by gambling 85 years later, now gobbles up real estate faster than a conventioneer chowing down at a midnight buffet. Every day of the week, two acres of Las Vegas area land are developed for commercial or residential use in a frenetic drive to accommodate the…

  9. Summary of chemical data from onsite and laboratory analyses of groundwater samples from the surficial aquifer, Las Vegas, Nevada, April and August 1993 and September 1994

    USGS Publications Warehouse

    Reddy, Michael M.; Gunther, Charmaine D.

    2012-01-01

    Samples were collected from groundwater wells in and about the city of Las Vegas, Nevada, and were analyzed for selected major, minor and trace constituents. Analyses of blank and reference samples are summarized as mean and standard deviation values for all positive results.

  10. Abundancias químicas de las estrellas CP del grupo HgMn μ Leporis y 53 Tauri. II. Boro, Berilio, Carbono, Magnesio, Aluminio y Silicio

    NASA Astrophysics Data System (ADS)

    López García, Z.; Malaroda, S. M.; Faraggiana, R.

    Se determinan las abundancias químicas de los elementos más livianos presentes en dos estrellas CP del grupo HgMn, μ Lep y 53 Tau, utilizando espectros IUE de alta resolución y técnicas de cálculo de espectros sintéticos. Para el cálculo de las líneas se utiliza la lista mas completa de datos atómicos disponible y el programa SYNTHE. Para el cálculo de la abundancia de un elemento se comparan, para cada imagen, los perfiles observados del mayor número de líneas presentes con los perfiles calculados obtenidos por variación de las abundancias iniciales, reteniendo la abundancia para la cual el acuerdo entre las líneas observadas y calculadas es considerado visualmente el mejor. Los resultados obtenidos son comparados con los estimados por la teoría de la difusión.

  11. About the Las Acacias, Trelew and Vassouras Magnetic Observatories Monitoring the South Atlantic Magnetic Anomaly Region Response to an Interplanetary Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Gianibelli, J. C.; Quaglino, N. M.

    2007-05-01

    The South Atlantic Magnetic Anomaly (SAMA) Region presents evolutive characteristics very important as were observed by a variety of satelital sensors. Important Magnetic Observatories with digital record monitor the effects of the Sun-Earth interaction, such as San Juan de Puerto Rico (SJG), Kourou (KOU), Vassouras (VSS), Las Acacias (LAS), Trelew (TRW), Vernadsky (AIA), Hermanus (HER) and Huancayo (HUA). In the present work we present the features registered during the geomagnetic storm in January 21, 2005, produced by a geoeffective Coronal Mass Ejection (CME) whose Interplanetary Coronal Mass Ejection (ICME) was detected by the instrumental onboard the Advanced Composition Explorer (ACE) Sonde. We analize how the Magnetic Total Intensity records at VSS, TRW and LAS Observatories shows the effect of the entering particles to ionospherical dephts producing a field enhancement following the first Interplanetary Shock (IP) arrival of the ICME. This process manifest in the digital record as an increment over the magnetospheric Ring Current field effect and superinpossed effects over the Antarctic Auroral Electrojet. The analysis and comparison of the records demonstrate that the Ring Current effects are important in SJG and KOU but not in VSS, LAS and TRW observatories, concluding that SAMA region shows a enhancement of the ionospherical currents oposed to those generated at magnetospheric heighs. Moreover in TRW, 5 hours after the ICME shock arrival, shows the effect of the Antarctic Auroral Electrojet counteracting to fields generated by the Ring Current.

  12. Mutational analysis of the quorum-sensing receptor LasR reveals interactions that govern activation and inhibition by non-lactone ligands

    PubMed Central

    Gerdt, Joseph P.; McInnis, Christine E.; Schell, Trevor L.; Rossi, Francis M.; Blackwell, Helen E.

    2014-01-01

    SUMMARY Gram-negative bacteria use N-acyl L-homoserine lactone (AHL) quorum sensing (QS) signals to regulate the expression of myriad phenotypes. Non-native AHL analogs can strongly attenuate QS receptor activity and thereby QS signaling; however, we currently lack a molecular understanding of the mechanisms by which most of these compounds elicit their agonistic or antagonistic profiles. In this study, we investigated the origins of striking activity profile switches (i.e., receptor activator to inhibitor, and vice versa) observed upon alteration of the lactone head group in certain AHL analogs. Reporter gene assays of mutant versions of the Pseudomonas aeruginosa QS receptor LasR revealed that interactions between the ligands and Trp60, Tyr56, and Ser129 govern whether these ligands behave as LasR activators or inhibitors. Using this knowledge, we propose a model for the modulation of LasR by AHL analogs—encompassing a subtly different interaction with the binding pocket to a global change in LasR conformation. PMID:25242287

  13. Explorations of Colleges, Universities, and Career Training Centers in Las Vegas, Nevada: Creating Educational and Training Programs for Displaced Workers to Learn Marketable Employment Skills

    ERIC Educational Resources Information Center

    Gonyea, Jacob Patrick

    2012-01-01

    The city of Las Vegas, Nevada has experienced a slowdown in tourism, a drop in property taxes and consolidated tax revenue used to support the city's operating budget, and a lack of economic diversification. Because of these changes, the ability of displaced workers to learn marketable employment skills continues to be an important issue for the…

  14. A McOndo Writer's Take on Literature in the Era of Audiovisual and Digital Communication: The Case of Alberto Fuguet's "Las Peliculas de mi vida"

    ERIC Educational Resources Information Center

    Maier, Linda S.

    2011-01-01

    Alberto Fuguet, one of the leaders of the McOndo writers who seek cultural direction from the United States and exploit mass-media formulas, is a polarizing figure in contemporary Latin American culture. His most recent full-length novel, the semi-autobiographical "Las peliculas de mi vida" (2003), has led many to conclude that Fuguet is simply a…

  15. Enhancement of archaeological heritage. El Risco de las Cuevas at Perales de Tajuña, Madrid (Spain)

    NASA Astrophysics Data System (ADS)

    Freire-Lista, David Martin; Alvarez de Buergo, Mónica; Fort, Rafael

    2016-04-01

    Heritage conservation has a great impact on the economy of a country. The enhancement of archaeological sites is an investment that promotes tourism and culture. The interdisciplinary knowledge of heritage should be the basis of its management. Preventive actions, non-destructive analytical techniques and monitoring for the conservation of these assets should be promoted. "El Risco de las Cuevas" is a highly decayed and nearly vertical gypsum escarpment which contains a series of dwellings excavated during the Chalcolithic and much more recent times. It is located at Perales de Tajuña, 40 km southeast of Madrid, Spain. This monument is approximately 70 metres high and 500 metres wide. It was listed as a cultural and monumental heritage site by the regional government of Madrid in 1998. The gypsum escarpment housing the dwellings forms part of a lower Miocene unit (Madrid Basin). Debris cones with a mixture of debris from the lower, medium and upper units are found at the bottom of the rockwall. The vulnerability of this monument to atmospheric agents has been studied using "in situ" monitoring techniques of humidity, temperature and rate of rockfalls. Drones have been used for aerial photography in the highest areas of the escarpment and have provided an information network of fractures likely to cause rockfall. Gypsum artificial accelerated ageing has been carried out in the laboratory, including freeze/thaw, wet/dry, thermal shock and dissolution tests. To determine the response of these accelerated ageing processes, density, micro-roughness, ultrasound velocities (Vp and Vs), air permeability and microscopy measurements were made before, during and after ageing tests. Geomorphological studies, rates of decay, material characteristics and durability tests indicate that the decay is controlled by the mineralogy, clay content and porosity of the gypsum rock, as well as microclimate, temperature changes and rock fractures. Rockfalls are particularly relevant in the

  16. Sedimentology and paleoenvironments of the Las Chacritas carbonate paleolake, Cañadón Asfalto Formation (Jurassic), Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Cabaleri, Nora G.; Benavente, Cecilia A.

    2013-02-01

    The Las Chacritas Member is the lower part of the Cañadón Asfalto Formation (Jurassic). The unit is a completely continental limestone succession with volcanic contributions that were deposited during the development of the Cañadón Asfalto Rift Basin (Chubut province, Patagonia, Argentina). A detailed sedimentological analysis was performed in the Fossati depocenter to determine the paleoenvironments that developed in the context of this rift. The Las Chacritas Member represents a carbonate paleolake system with ramp-shaped margins associated with wetlands that were eventually affected by subaerial exposure and pedogenesis. This process is represented by three main subenvironments: a) a lacustrine setting sensu stricto (lacustrine limestone facies association), represented by Mudstones/Wackestones containing porifera spicules (F1), Intraclastic packstones (F6) and Tabular stromatolites (F10) in which deposition and diagenesis were entirely subaqueous; b) a palustrine setting (palustrine limestone facies association) containing Microbial Mudstones (F2), Intraclastic sandy packstone with ostracode remains (F3), Oncolitic packstone (F5), Brecciated limestone (F7) and Nodular-Mottled limestone (F8) representing shallow marginal areas affected by groundwater fluctuations and minor subaerial exposure; and c) a pedogenic paleoenvironment (pedogenic limestone facies association) including Intraclastic limestone (F4) and Packstones containing Microcodium (F9) facies displaying the major features of subaerial exposure, pedogenic diagenesis and the development of paleosols. The fluvial-palustrine-lacustrine succession shows a general shallow upward trend in which contraction-expansion cycles are represented (delimited by exposure and surface erosion). The variations in the successive formations reflect the responses to fluctuations in a combination of two major controls, the tectonic and local climatic variables. The predominance of the palustrine facies associations was

  17. Volcán Las Navajas, a Pliocene-Pleistocene trachyte/peralkaline rhyolite volcano in the northwestern Mexican volcanic belt

    NASA Astrophysics Data System (ADS)

    Nelson, Stephen A.; Hegre, Joann

    1990-01-01

    Volcán Las Navajas, a Pliocene-Pleistocene volcano located in the northwestern portion of the Mexican volcanic belt, erupted lavas ranging in composition from alkali basalt through peralkaline rhyolite, and is the only volcano in mainland Mexico known to have erupted pantellerites. Las Navajas is located near the northwestern end of the Tepic-Zacoalco rift and covers a 200-m-thick pile of alkaline basaltic lavas, one of which has been dated at 4.3 Ma. The eruptive history of the volcano can be divided into three stages separated by episodes of caldera formation. During the first stage a broad shield volcano made up of alkali basalts, mugearites, benmoreites, trachytes, and peralkaline rhyolites was constructed. Eruption of a chemically zoned ash flow then caused collapse of the structure to form the first caldera. The second stage consisted of eruptions of glassy pantellerite lavas that partially filled the caldera and overflowed its walls. This stage ended about 200 000 years ago with the eruption of pumice falls and ash flows, which led to the collapse of the southern portion of the volcano to form the second caldera. During the third stage, two benmoreite cinder cones and a benmoreite lava flow were emplaced on the northwestern flank of the volcano. Finally, the calc-alkaline volcano Sanganguey was built on the southern flank of Las Lavajas. Alkaline volcanism continued in the area with eruptions of alkali basalt from cinder cones located along NW-trending fractures through the area. Although other mildly peralkaline rhyolites are found in the rift zones of western Mexico, only Las Navajas produced pantellerites. Greater volumes of basic alkaline magma have erupted in the Las Navajas region than in the other areas of peralkaline volcanism in Mexico, a factor which may be necessary to provide the initial volume of material and heat to drive the differentiation process to such extreme peralkaline compositions.

  18. Environmental and social determinants of youth physical activity intensity levels at neighborhood parks in Las Vegas, NV.

    PubMed

    Coughenour, Courtney; Coker, Lisa; Bungum, Tim J

    2014-12-01

    Parks can play an important role in youth activity. This study used observational data to evaluate the relationship of environmental and social determinants to youth physical activity intensity levels in Las Vegas neighborhood parks. System for observing play and leisure activity in youth was used to code activity levels as sedentary, walking, or vigorous in five low-income and five high-income parks. Environmental determinants included amenities, incivilities, size, high-speed streets, sidewalk condition, and temperature. Social determinants included percent minority and Hispanic, gender, and income. A multinomial logistic regression model was performed. We observed 1,421 youth, 59% male, 41% female; 21% were sedentary, 38% walking, and 41% vigorous. Males were more likely to be observed walking (OR 1.42) and vigorous (OR 2.21) when compared to sedentary. High-speed streets (OR 0.76), sidewalks condition (OR 0.34), and low-income neighborhoods (OR 0.07) was associated with decreased odds of vigorous activity; incivilities (OR 1.34) and amenities (OR 1.27) were associated with greater odds of being vigorous. Environmental and social determinants are associated with physical activity intensity levels at parks. Stakeholders should ensure quality parks, as they relate to physical activity levels in youth. Understanding environmental and social determinants that influence physical activity at parks is critical to utilizing their full potential in an effort to combat childhood obesity.

  19. Characteristics of Combined Submerged Membrane Bioreactor with Granular Activated Carbon (GAC) in Treating Lineal Alkylbenzene Sulphonates (LAS) Wastewater

    NASA Astrophysics Data System (ADS)

    Guo, Jifeng; Xia, Siqing; Lu, Yanjun

    2010-11-01

    A combined MBR (cMBR) with granular activated carbon (GAC) was used as a backbone system to treat the synthetic lineal alkylbenzene sulphonates (LAS) wastewater. The GAC was added in the MBR to improve the resistance of membrane fouling. A parallel conventional MBR (pMBR) without the GAC was run to give a contrast. The results of the process demonstrate that the cMBR process was more efficient than pMBR. It was found that the TMP changes of the cMBR were slower than the pMBR. The results demonstrated that the cMBRs membrane was better than the pMBR's after a clean period run. It was the GAC scrubbing to the membrane that delayed the membrane fouling of the cMBR. Variable critical flux was found in MBR, which showed that the cMBR could make the critical flux better than pMBR in the run time, but GAC could not improve the critical flux at the end of the period for the severe membrane fouling. Based on this theory, a variable critical flux (J) of MBR was put forward, and the relationship of J with time (t) was: J = 16.081e-0.0177t.

  20. Seismic activity and stress tensor inversion at Las Tres Vírgenes Volcanic and Geothermal Field (México)

    NASA Astrophysics Data System (ADS)

    Antayhua-Vera, Yanet; Lermo-Samaniego, Javier; Quintanar-Robles, Luis; Campos-Enríquez, Oscar

    2015-10-01

    We analyze local earthquakes occurring between 2003 and 2012 at the Las Tres Vírgenes Volcanic and Geothermal Field (TVVGF) to establish their temporal and spatial distribution, and relationships with local and regional fault systems, water injection, acid stimulation and steam production tests. We obtained focal mechanisms and inverted data for the stress tensor to understand the local and regional stress fields. We analyzed 423 local earthquakes with magnitudes between 0.1 and 2.9 Mc and hypocentral depths from 0.2 to 7.4 km b.s.l. The cutoff depth at ~ 7.4 km possibly delineates the brittle-ductile transition zone. We identified seven swarms (from 1 to 7). Swarms 1 (December 2009), 2 (May 2010), 3 (June-July 2010) and 7 (December 2012) are strongly correlated with injection processes; whereas swarms 5 (April 2012) and 6 (September 2012) are correlated with local tectonic faults. Stress inversion showed NW-SE, E-W and NE-SW extensional orientations (Shmin), in agreement with the local tectonic stress field; while NE-SW compressional orientations (SHmax) are correlated with the regional tectonic stress field.

  1. Estimation of spatio-temporal recharge of aquifers in mountainous karst terrains: Application to Sierra de las Nieves (Spain)

    NASA Astrophysics Data System (ADS)

    Pardo-Igúzquiza, E.; Durán-Valsero, J. J.; Dowd, P. A.; Guardiola-Albert, C.; Liñan-Baena, C.; Robledo-Ardila, P. A.

    2012-11-01

    SummaryWe describe a method for estimating the daily, spatially distributed recharge of aquifers in mountainous karst terrains using a water balance. Water recharge into an aquifer is a highly variable process over both time and space. Many methods have been developed to assess aquifer recharge although most have been applied to detrital aquifers. Many karst aquifers, especially in Mediterranean areas, occur in mountainous environments where rainfall and evapotranspiration can vary considerably over space and time and where there are usually few rainfall and temperature monitoring stations. We have used an advanced geostatistical method to estimate daily rainfall and temperature. The method involves kriging with an external drift using a climatological semi-variogram model inferred by modified maximum-likelihood. The depth of the soil-epikarst layer is estimated from remote sensing and terrain analysis data together with field observations and electrical resistivity tomography. Because of the karst nature of the mountainous terrain, concentrated infiltration is allowed for in some places. The parameters are calibrated against the cumulative discharge of various springs. The method is illustrated by a case study of the Sierra de las Nieves aquifer in the mountainous karst region of southern Spain.

  2. Depositional sequences and correlation of middle to Upper Miocene reef complexes, Nijar and Las Negras Areas, Southeastern Spain

    SciTech Connect

    Franseen, E.K.; Mankiewicz, C.; Pray, L.C.

    1988-01-01

    During the Serravallian through Messinian, reefs fringed topographic highs that rimmed Neogene basins in the western Mediterranean. Detailed studies of middle to upper Miocene carbonate strata in the Nijar and Las Negras areas (southeastern Spain) document the effects of relative sea level change on sedimentation, biotic composition, reef development, and diagenesis. The authors have identified several previously unrecognized, regionally correlatable depositional sequences and erosional breaks that the authors interpret resulted from sea level fluctuations. Limited microfossil dating and correlation of depositional successions with third-order eustatic sea level curves suggest that most carbonate deposition occurred during the Serravallian and Tortonian, not Messinian as formerly thought. Uppermost strata (upper Tortonian> predominately comprise pack-stones and grainstones of distal to proximal reef-foreslope and reef-talus facies that dip 10/sup 0/-30/sup 0/. Reef core, mostly Porites framework, is locally preserved. Field geometries indicate minimum self-to-basin relief of 100 m. The authors' results of studies suggest that detailed field studies coupled with the use of published eustatic sea level curves may provide a powerful tool for correlation of middle to upper Miocene strata not only in Spain, but in the entire western Mediterranean.

  3. Mixed carbonate and volcaniclastic slope facies in a middle to upper Miocene archipelago, Las Negras and Rodalquilar areas, southeastern Spain

    SciTech Connect

    Franseen, E.K. )

    1990-05-01

    The Las Negras and Rodalquilar areas contain excellent exposures of middle to upper Miocene carbonate and volcaniclastic deposits that fringe earlier formed Neogene volcanic substrates in an archipelago setting. The Miocene sedimentary sequence consists of three depositional sequences composed of reworked volcanic rocks and reef crest to distal slope strata that display 100-200 m of relief over 0.5-2.0 km. The entire sequence is truncated by a regional subaerial unconformity. The lower two depositional sequences are composed predominantly of shallow-dipping, normal marine, distal to proximal slope wackestones and packstones. The two sequences are separated by a megabreccia composed of Tarbellastreaea and Porites blocks and volcaniclastic sandstones and conglomerates. The reef blocks likely developed as upslope patch reefs, and, with the volcaniclastics, were eroded and transported via mass movements and tractive currents to a distal slope position. The upper (third) depositional sequence consists predominantly of foreslope strata of a Porites-dominated fringing reef complex. The base of this sequence is characterized by a megabreccia of Porites reef blocks, shallow-marine packstones, or volcaniclastic conglomerates. Five volcaniclastic wedges, interpreted as fan delta deposits, alternate with prograding carbonate foreslope deposits likely as a response to high frequency relative sea level fluctuations during a new sea level fall. The apparent correlatability of similar deposition sequences throughout the region indicates the importance of sequence development from allogenic processes, including glacio-eustatic sea level fluctuations and tectonism associated with the isolation of the Mediterranean Sea during the latest Miocene.

  4. Characterization and prediction of spatial variability of unsaturated hydraulic properties in a field soil: Las Cruces, New Mexico

    SciTech Connect

    Yeh, T.C.J.; Greenholtz, D.E.; Nash, M.S.; Wierenga, P.J.

    1991-12-31

    A 91-m transect was set up in an irrigated field near Las Cruces, New Mexico to investigate the spatial variability of unsaturated soil properties. A total of 455 sampling points were monitored along a grid consisting of 91 stations placed 1 m apart by 5 depths per station. Post-irrigation soil water tension and water content measurements were recorded over 45 days at 11 time periods. The instantaneous profile was used to estimate the unsaturated hydraulic conductivity at the 455 sampling points. Fifty soil samples were also taken for analyzing sand, silt, and clay content distributions. The spatial and temporal variability of soil water tension and water content were investigated along with the spatial variability of parameters of an unsaturated hydraulic conductivity model. Results of the analysis show that spatial variation in soil water tension and water content is consistent with the soil texture spatial variability. In addition, the spatial distribution of the estimated parameter value of unsaturated hydraulic conductivity reflects the soil texture distribution. Using the statistics of the estimated hydraulic parameter values, a stochastic soil water tension model was employed to reproduce the variability of observed soil water tension. Although many assumptions were made, the results of the simulation appear promising.

  5. Characterization and prediction of spatial variability of unsaturated hydraulic properties in a field soil: Las Cruces, New Mexico

    SciTech Connect

    Yeh, T.C.J.; Greenholtz, D.E. . Dept. of Hydrology and Water Resources); Nash, M.S. . Dept. of Crop and Soil Sciences); Wierenga, P.J. . Dept. of Soil and Water Science)

    1991-01-01

    A 91-m transect was set up in an irrigated field near Las Cruces, New Mexico to investigate the spatial variability of unsaturated soil properties. A total of 455 sampling points were monitored along a grid consisting of 91 stations placed 1 m apart by 5 depths per station. Post-irrigation soil water tension and water content measurements were recorded over 45 days at 11 time periods. The instantaneous profile was used to estimate the unsaturated hydraulic conductivity at the 455 sampling points. Fifty soil samples were also taken for analyzing sand, silt, and clay content distributions. The spatial and temporal variability of soil water tension and water content were investigated along with the spatial variability of parameters of an unsaturated hydraulic conductivity model. Results of the analysis show that spatial variation in soil water tension and water content is consistent with the soil texture spatial variability. In addition, the spatial distribution of the estimated parameter value of unsaturated hydraulic conductivity reflects the soil texture distribution. Using the statistics of the estimated hydraulic parameter values, a stochastic soil water tension model was employed to reproduce the variability of observed soil water tension. Although many assumptions were made, the results of the simulation appear promising.

  6. The Remote Measurement of Carbon Dioxide by the CO2LAS Instrument during the 2011 ASCENDS Field Campaign

    NASA Astrophysics Data System (ADS)

    Spiers, G. D.; Menzies, R. T.; Jacob, J. C.; Geier, S.

    2012-12-01

    The Carbon Dioxide Laser Absorption Spectrometer, CO2LAS, is a laser based instrument developed by the Jet Propulsion Laboratory for the remote measurement of the column weighted carbon dioxide concentration from an aircraft. It has undergone a number of developmental and test flights, the most recent of which which was conducted from the NASA DC-8 aircraft during the summer of 2011 as part of the Active Sensing of CO2 Emissions through Nights, Days, and Seasons, ASCENDS, Earth Science Decadal Survey Mission Development Studies. We present refined results from two flights conducted during that campaign as well as new results from other flights during that campaign. We demonstrate an improvement on our ability to measure CO2 drawdown due to crop activity during flights over the great plains area, revise our ability to make CO2 column measurements over complex terrain in the presence of snow and demonstrate high spatial resolution measurements of CO2 plumes from individual stack clusters of the Four Corners Power plant. In addition we describe improved algorithms that allow us to discriminate against cloud contamination in the instrument field of view without requiring a range resolved measurement. We will conclude with a brief summary of instrument improvements and plans for future campaigns.

  7. Computational discovery of putative quorum sensing inhibitors against LasR and RhlR receptor proteins of Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Annapoorani, Angusamy; Umamageswaran, Venugopal; Parameswari, Radhakrishnan; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2012-09-01

    Drugs have been discovered in the past mainly either by identification of active components from traditional remedies or by unpredicted discovery. A key motivation for the study of structure based virtual screening is the exploitation of such information to design targeted drugs. In this study, structure based virtual screening was used in search for putative quorum sensing inhibitors (QSI) of Pseudomonas aeruginosa. The virtual screening programme Glide version 5.5 was applied to screen 1,920 natural compounds/drugs against LasR and RhlR receptor proteins of P. aeruginosa. Based on the results of in silico docking analysis, five top ranking compounds namely rosmarinic acid, naringin, chlorogenic acid, morin and mangiferin were subjected to in vitro bioassays against laboratory strain PAO1 and two more antibiotic resistant clinical isolates, P. aeruginosa AS1 (GU447237) and P. aeruginosa AS2 (GU447238). Among the five compounds studied, except mangiferin other four compounds showed significant inhibition in the production of protease, elastase and hemolysin. Further, all the five compounds potentially inhibited the biofilm related behaviours. This interaction study provided promising ligands to inhibit the quorum sensing (QS) mediated virulence factors production in P. aeruginosa.

  8. late Pleistocene and Holocene pollen record from Laguna de las Trancas, northern coastal Santa Cruz County, California

    USGS Publications Warehouse

    Adam, David P.; Byrne, Roger; Luther, Edgar

    1981-01-01

    A 2.1-m core from Laguna de las Trancas, a marsh atop a landslide in northern Santa Cruz County, California, has yielded a pollen record for the period between about 30,000 B. P. and roughly 5000 B. P. Three pollen zones are recognized. The earliest is characterized by high frequencies of pine pollen and is correlated with a mid-Wisconsinan interstade of the mid-continent. The middle zone contains high frequencies of both pine and fir (Abies, probably A. grandis) pollen and is correlated with the last full glacial interval (upper Wisconsinan). The upper zone is dominated by redwood (Sequoia) pollen and represents latest Pleistocene to middle Holocene. The past few thousand years are not represented in the core. The pollen evidence indicates that during the full glacial period the mean annual temperature at the site was about 2°C to 3°C lower than it is today. We attribute this small difference to the stabilizing effect of marine upwelling on the temperature regime in the immediate vicinity of the coast. Precipitation may have been about 20 percent higher as a result of longer winter wet seasons.

  9. Can a Spanish science education journal become international? the case of Enseñanza de las Ciencias

    NASA Astrophysics Data System (ADS)

    Espinet, Mariona; Izquierdo, Mercè; Garcia-Pujol, Clara

    2015-12-01

    In this paper we discuss the case of the science education research journal Enseñanza de las Ciencias (EC) around the issue of its internationalization and the consequences this process has had and is still having on the use and preservation of different languages and more specifically the Castilian (Spanish) language. We first frame the concept of globalization and internationalization, and identify three important dimensions involved in the process of internationalization of EC such as language use, actors involved and resources available. Secondly, we address the historical evolution of EC along three phases of internationalization. In each phase we discuss the tensions experienced in relevant internationalization dimensions focusing particularly on the use of languages. We conclude by advocating a plurilingual and multicultural model for a science education research journal as an alternative to the hegemony of international English written journals. In doing so we want to continue the conversation on the role that local and national science education research journals have in promoting science education around the world.

  10. Nuevos escenarios de la migración México-Estados Unidos. Las consecuencias de la guerra antiinmigrante

    PubMed Central

    MASSEY, Douglas S.; PREN, Karen A.; DURAND, Jorge

    2010-01-01

    La historia de la migración México-Estados Unidos se caracteriza por una serie de periodos durante los cuales los patrones migratorios se transforman y evolucionan como respuesta a los cambios en la política migratoria de Estados Unidos. En la década de 1990 se dio uno de estos cambios, lo que provocó el paso de la ‘era de la contradicción’ a la ‘era de la marginalización’. Actualmente, un gran número de migrantes indocumentados permanecen al margen de la ley, precisamente en un periodo en el que las penas se han incrementado y la persecución ha alcanzado niveles récord. De manera cada vez más notoria, los migrantes indocumentados, por la represión interna y fronteriza, quedan obligados a romper los lazos que los vinculaban con sus lugares de destino, pero al mismo tiempo se sienten cada vez más extraños en una tierra donde la aplicación de políticas antiinmigrantes es cosa de todos los días, lo que los sitúa en una posición de marginalización y gran vulnerabilidad. PMID:21209790

  11. Site formation and chronology of the new Paleolithic site Sima de Las Palomas de Teba, southern Spain

    NASA Astrophysics Data System (ADS)

    Kehl, Martin; Burow, Christoph; Cantalejo, Pedro; Domínguez-Bella, Salvador; Durán, Juan José; Henselowsky, Felix; Klasen, Nicole; Linstädter, Jörg; Medianero, Javier; Pastoors, Andreas; Ramos, José; Reicherter, Klaus; Schmidt, Christoph; Weniger, Gerd-Christian

    2016-03-01

    The newly identified Paleolithic site Sima de Las Palomas de Teba hosts an almost seven-m-thick sediment profile investigated here to elucidate the rock shelter's chronostratigraphy and formation processes. At its base, the sediment sequence contains rich archeological deposits recording intensive occupation by Neanderthals. Luminescence provides a terminus ante quem of 39.4 ± 2.6 ka or 44.9 ± 4.1 ka (OSL) and 51.4 ± 8.4 ka (TL). This occupation ended with a rockfall event followed by accumulation of archeologically sterile sediments. These were covered by sediments containing few Middle Paleolithic artifacts, which either indicate ephemeral occupation by Neanderthals or reworking as suggested by micromorphological features. Above this unit, scattered lithic artifacts of undiagnostic character may represent undefined Paleolithic occupations. Sediment burial ages between about 23.0 ± 1.5 ka (OSL) and 40.5 ± 3.4 ka (pIRIR) provide an Upper Paleolithic chronology for sediments deposited above the rockfall. Finally, a dung-bearing Holocene layer in the uppermost part of the sequence contains a fragment of a human mandible dated to 4032 ± 39 14C yr BP. Overall, the sequence represents an important new site for studying the end of Neanderthal occupation in southern Spain.

  12. Bioaccumulation and toxicity of 4-nonylphenol (4-NP) and 4-(2-dodecyl)-benzene sulfonate (LAS) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta).

    PubMed

    Mäenpää, K; Kukkonen, J V K

    2006-05-10

    The discharge of surfactants, such as 4-nonylphenol (4-NP) and linear alkylbenzene sulfonates (LAS), into water bodies leads to accumulation of the chemicals in the sediments and may thus pose a problem to benthic organisms. To study the bioaccumulation of surfactants, Oligochaeta worm Lumbriculus variegatus was exposed to sediment-spiked, [14C]-labeled 4-NP and 4-(2-dodecyl)-benzene sulfonate (C12-LAS) in three different sediments (S1-S3). The sediments were characterized for organic carbon (OC) content and particle size distribution. The acute toxicity was examined by exposing L. variegatus and three to four instar Chironomus riparius (Insecta) larvae in water-only exposure to 4-NP and LAS at different concentrations. After 48-h exposure, lethal water concentrations (LC50) and lethal body residues (LBR50) were estimated using liquid scintillation counting. Chronic toxicity was evaluated in two different sediments by exposing first instar C. riparius larvae to sediment-spiked chemicals at different concentrations. After 10 days, the sublethal effects of surfactants were observed by measuring wet weight and head capsule length. Finally, another 10-day test was set up in order to measure the LAS body residues associated with sublethal effects in C. riparius in S2 sediment. The bioaccumulation test revealed that the bioaccumulation of both 4-NP and LAS increased as the sediment organic matter content decreased. It is assumed that the chemical binding to organic material decreased chemical bioavailability. The acute toxicity tests showed that L. variegatus was more tolerant of 4-NP, and C. riparius was more tolerant of LAS when based on water exposure concentration. The LBR-estimates revealed, however, that L. variegatus tolerated clearly higher tissue residues of both chemicals compared with C. riparius. Both chemicals had sublethal effects on C. riparius growth in sediment exposure, reducing larvae wet weight and head capsule size. 4-NP, however, showed an irregular

  13. The Las Vegas Thesis

    ERIC Educational Resources Information Center

    Sughrua, William

    2010-01-01

    Following "reflexive ethnography" and utilizing an approach of "performative narrative" and "layered text", this article explores how Bachelor of Arts students in the Teaching of English as a Foreign Language program at a public university in Mexico successfully manage the writing of an inductive-oriented thesis in…

  14. Hydrologic, water-quality, and biological assessment of Laguna de las Salinas, Ponce, Puerto Rico, January 2003-September 2004

    USGS Publications Warehouse

    Soler-López, Luis R.; Gómez-Gómez, Fernando; Rodríguez-Martínez, Jesús

    2005-01-01

    The Laguna de Las Salinas is a shallow, 35-hectare, hypersaline lagoon (depth less than 1 meter) in the municipio of Ponce, located on the southern coastal plain of Puerto Rico. Hydrologic, water-quality, and biological data in the lagoon were collected between January 2003 and September 2004 to establish baseline conditions. During the study period, rainfall was about 1,130 millimeters, with much of the rain recorded during three distinct intense events. The lagoon is connected to the sea by a shallow, narrow channel. Subtle tidal changes, combined with low rainfall and high evaporation rates, kept the lagoon at salinities above that of the sea throughout most of the study. Water-quality properties measured on-site (temperature, pH, dissolved oxygen, specific conductance, and Secchi disk transparency) exhibited temporal rather than spatial variations and distribution. Although all physical parameters were in compliance with current regulatory standards for Puerto Rico, hyperthermic and hypoxic conditions were recorded during isolated occasions. Nutrient concentrations were relatively low and in compliance with current regulatory standards (less than 5.0 and 1.0 milligrams per liter for total nitrogen and total phosphorus, respectively). The average total nitrogen concentration was 1.9 milligrams per liter and the average total phosphorus concentration was 0.4 milligram per liter. Total organic carbon concentrations ranged from 12.0 to 19.0 milligrams per liter. Chlorophyll a was the predominant form of photosynthetic pigment in the water. The average chlorophyll a concentration was 13.4 micrograms per liter. Chlorophyll b was detected (detection limits 0.10 microgram per liter) only twice during the study. About 90 percent of the primary productivity in the Laguna de Las Salinas was generated by periphyton such as algal mats and macrophytes such as seagrasses. Of the average net productivity of 13.6 grams of oxygen per cubic meter per day derived from the diel

  15. Palinspastic reconstruction of Lower Mesozoic stratigraphic sequences near the latitude of Las Vegas: Implications for the entire Great Basin

    SciTech Connect

    Marzolf, J.E. . Dept. of Geology)

    1993-04-01

    On the Colorado Plateau, lower Mesozoic stratigraphy is subdivided by regional unconformities into the Lower Triassic Moenkopi, Upper Triassic Chinle, Lower and Middle( ) Jurassic Glen Canyon, and Middle Jurassic lower San Rafael tectonosequences. Palinspastic reconstruction for Cenozoic extensional and mesozoic compressional deformations near the latitude of Las Vegas indicates the Moenkopi tectono-sequence constructed a passive-margin-like architecture of modest width overlapping folded. Thrust-faulted, and intruded Permian strata, with state boundaries fixed relative to the Colorado Plateau, comparison of the location of the Early Triassic shelf-slope break near latitude 36[degree] with the palinspastically restored location of the shelf-slope break in southeastern Idaho implies strata of the Moenkopi tectonosequence in the Mesozoic marine province of northwest NV lay in western utah in the Early Triassic. This reconstruction: suggests that the Galconda and Last Chance faults are part of the same thrust system; aligns late Carnian paleovalleys of the chinle tectonosequence on the Colorado Plateau with a coeval northwest-trending paleovalley cut across the Star Pea, and the Norian Cottonwood paleovalley with the coeval Grass Valley delta; defines a narrow, northward deepening back-arc basin in which the Glen Canyon tectonosequence was deposited; aligns east-facing half grabens along the back side of the arc from the Cowhole Mountains to the Clan Alpine Range; projects the volcan-arc/back-arc transition from northwest Arizona to the east side of the Idaho batholith; and predicts the abrupt facies change from silicic volcanics to marine strata of the lower San Rafael sequence lay in western Utah. The paleogeographic was altered in the late Bathonian to Callovian by back-arc extension north of a line extending from Cedar City, UT to Mina, NV. The palinspastic reconstruction implies the Paleozoic was tectonically stacked at the close of the Paleozoic.

  16. Particle Count and Black Carbon Measurements at Schools in Las Vegas and in the Greater Salt Lake City Area.

    PubMed

    Brown, Steven G; Vaughn, David L; Roberts, Paul T

    2016-12-23

    As part of two separate studies aimed to characterize ambient pollutant concentrations at schools in urban areas, we compare black carbon and particle count measurements at Adcock Elementary in Las Vegas, Nevada (April-June 2013), and Hunter High School in the West Valley City area of Greater Salt Lake City, Utah (February 2012). Both schools are in urban environments, but Adcock Elementary is next to the U.S. 95 freeway. Black Carbon (BC) concentrations were 13% higher at Adcock compared to Hunter, while particle count concentrations were 60% higher. When wind speeds were low-less than 2 m/sec-both BC and particle count concentrations were significantly higher at Adcock, while concentrations at Hunter did not have as strong a variation with wind speed. When wind speeds were less than 2 m/s, emissions from the adjacent freeway greatly affected concentrations at Adcock, regardless of wind direction. At both sites, BC and particle count concentrations peaked in the morning during commute hours. At Adcock, particle count also peaked during midday or early afternoon, when BC was low and conditions were conducive to new particle formation. While this midday peak occurred at Adcock on roughly 45% of the measured days, it occurred on only about 25% of the days at Hunter, since conditions for particle formation (higher solar radiation, lower wind speeds, lower relative humidity) were more conducive at Adcock. Thus, children attending these schools are likely to be exposed to pollution peaks during school drop-off in the morning, when BC and particle count concentrations peak, and often again during lunchtime recess when particle count peaks again.

  17. Computer graphics synthesis for inferring artist studio practice: an application to Diego Velázquez's Las Meninas[

    NASA Astrophysics Data System (ADS)

    Stork, David G.; Furuichi, Yasuo

    2009-02-01

    Diego Velázquez's Las meninas (1656) has been called by some art experts "the most important painting of the 17th century," "a theology of painting," and even "the world's greatest painting"; it has been the subject of intensive study. The work depicts a complex scene in the Alcázar palace of King Philip IV of Spain, and includes mirror reflections of the king and queen, apparently standing in place of the viewer, as well as the artist himself standing before an enormous canvas on an easel. Nevertheless, questions remain about the studio and the proper viewing configuration: Is the artist looking toward the perspectivally correct position of the viewer in the museum space (center of projection), outside the picture space? Does the perspectivally correct position correspond to the locations of the king and queen seen reflected in the mirror? Is the bright illumination on the king and queen (as revealed in the mirror) consistent with the lighting in the tableau itself? We addressed these questions in a new way: by building a full computer graphics model of the figures and tableau as well as the viewer's space outside the painting. In our full model, the painting itself is represented as a translucent window onto which the picture space is projected toward the center of projection, that is, the viewer. Our geometric and (new) lighting evidence confirm Janson's and Snyder's contention that the plane mirror on the back wall reflects the other side of the large painting depicted within the tableau, not the king and queen themselves in the studio. We believe our computer graphics synthesis of both the tableau within the painting and the viewer's space in the real world is the first of its kind to address such problems in the history of art.

  18. Structural controls on karstic conduits in a collisional orogen (Sierra de las Nieves, Betic Cordillera, S Spain)

    NASA Astrophysics Data System (ADS)

    Pedrera, A.; Luque-Espinar, J. A.; Martos-Rosillo, S.; Pardo-Igúzquiza, E.; Durán-Valsero, J. J.; Martínez-Moreno, F.; Guardiola-Albert, C.

    2015-06-01

    We characterize the fracture pattern, including both meso-scale joints and macro-scale faults, within the central sector of Sierra de las Nieves (Betic Cordillera, S Spain), which contains one of the largest karstification systems in Europe. Structural data were compared with the direction pattern of the karstic conduit network of the largest caves. Carbonate rocks were deformed in a collisional setting and exposed at the surface since the early Miocene. Normal and normal-oblique faults trending NW-SE to WNW-ESE are the most prominent brittle structures, having formed coevally with shorter NE-SW normal to normal-dextral after the main thrusting phase. In addition, two main open joint sets striking NW-SE and NE-SW developed on a broad scale. Orthogonal normal faults and open joints suggest an extensional setting characterized by horizontal minimum (S3) and intermediate (S2) stress axes of similar magnitudes that intermittently shifted their positions during the middle-to-late Miocene. Vertical water flow coming from direct recharge sectors tends to infiltrate across these high-dipping faults, mainly concentrating at fault intersections, thus favoring sub-vertical conduit formation within the vadose zone. Horizontal paleo-phreatic levels are perched linked to the recent uplift undergone by the sector, giving us the opportunity to analyze the incidence of fractures at the phreatic zone. Joint sets determine the hydraulic anisotropy within the former phreatic levels. Because our study illustrates the primary role of diverse tectonic structures during massive multiphase cave development above and below the water table, it could contribute to better constraining of the models of karstic conduit formation.

  19. The high-grade Las Cruces copper deposit, Spain: a product of secondary enrichment in an evolving basin

    NASA Astrophysics Data System (ADS)

    Tornos, Fernando; Velasco, Francisco; Slack, John F.; Delgado, Antonio; Gomez-Miguelez, Nieves; Escobar, Juan Manuel; Gomez, Carmelo

    2017-01-01

    The Las Cruces deposit (Iberian Pyrite Belt) includes a large, high-grade cementation zone capped by unusual rocks that contain carbonates, galena, iron sulphides, and quartz. Between the Late Cretaceous(?) and Tortonian, the volcanogenic massive sulphides were exhumed and affected by subaerial oxidation that formed paired cementation and gossan zones. Onset of Alpine extension produced accelerated growth of the cementation zone along extensional faults, leading to formation of the high-grade copper ore at ca. 11 Ma. Later, replacement of the overlying gossan by sulphide- and carbonate-rich rocks beneath sealing marl sediments is thought to have involved microbial processes, occurring between the Messinian (ca. 7.2 Ma) and today. Isotope data show that the cementation zone formed by the mixing of descending acidic waters derived from oxidation of the massive sulphides, with upwelling geothermal waters flowing at temperatures above 100 °C. The C, O, and Sr isotope values of the mineralization (87Sr/86Sr 0.7101-0.7104) and of the local groundwater (0.7102-0.7104) reflect equilibration with basement rocks, and indicate that influence on the ore-forming process by marl-equilibrated water (0.7091-0.7093) or Miocene seawater (0.7086-0.7092) was negligible. The high sulphur isotope values of the sulphides in the biogenic zone (most +19 to +24 ‰) are well above those of the primary sulphides (δ34S ca. -6.8 to +10.3 ‰) and likely reflect formation of the biogenic sulphides by reduction of aqueous sulphate in the groundwaters. Sulphur isotope values of the cementation zone (δ34S ca. -2.4 to +21.7 ‰) are also consistent with some contribution of sulphur from the biogenic reduction of aqueous sulphate.

  20. Sr Isotopes and Migration of Prairie Mammoths (Mammuthus columbi) from Laguna de las Cruces, San Luis Potosi, Mexico

    NASA Astrophysics Data System (ADS)

    Solis-Pichardo, G.; Perez-Crespo, V.; Schaaf, P. E.; Arroyo-Cabrales, J.

    2011-12-01

    Asserting mobility of ancient humans is a major issue for anthropologists. For more than 25 years, Sr isotopes have been used as a resourceful tracer tool in this context. A comparison of the 87Sr/86Sr ratios found in tooth enamel and in bone is performed to determine if the human skeletal remains belonged to a local or a migrant. Sr in bone approximately reflects the isotopic composition of the geological region where the person lived before death; whereas the Sr isotopic system in tooth enamel is thought to remain as a closed system and thus conserves the isotope ratio acquired during childhood. Sr isotope ratios are obtained through the geologic substrate and its overlying soil, from where an individual got hold of food and water; these ratios are in turn incorporated into the dentition and skeleton during tissue formation. In previous studies from Teotihuacan, Mexico we have shown that a three-step leaching procedure on tooth enamel samples is important to assure that only the biogenic Sr isotope contribution is analyzed. The same Sr isotopic tools can function concerning ancient animal migration patterns. To determine or to discard the mobility of prairie mammoths (Mammuthus columbi) found at Laguna de las Cruces, San Luis Potosi, México the leaching procedure was applied on six molar samples from several fossil remains. The initial hypothesis was to use 87Sr/86Sr values to verify if the mammoth population was a mixture of individuals from various herds and further by comparing their Sr isotopic composition with that of plants and soils, to confirm their geographic origin. The dissimilar Sr results point to two distinct mammoth groups. The mammoth population from Laguna de Cruces was then not a family unit because it was composed by individuals originated from different localities. Only one individual was identified as local. Others could have walked as much as 100 km to find food and water sources.

  1. Toxicity of a Novel Herbomineral Preparation Las01 on Human Cancer Cell Lines and Its Safety Profile in Humans and Animals

    PubMed Central

    Sheikh, Saba; Srivastava, Ashok; Tripathi, Rajesh; Tripathi, Shalini; Trivedi, V. P.; Saxena, R. C.

    2012-01-01

    Polyhedral formulations based on Rasayana therapy described in Charaka Samhita showed remarkable improvement in quality of life of various cancer patients who have been found to be refractory or poor responders to modern chemotherapy and radiation treatment. One of the most recent novel herbomineral preparation, Las01 prepared absolutely as per the instruction given in the ancient Ayurvedic literature has been found to be effective as a potent anticancer drug in the human cell lines, the MCF-7 and Hela cancer cell lines. This novel preparation of Las01 is also found to be devoid of toxicity both in animals as well as in human subjects, which is the main drawback of chemotherapeutic agents used in modern system of medicine. Our results warrant multicentric clinical trials on a large scale which seems to be a future promising drug to cure incurables cancer patients. PMID:22969832

  2. Estructura espacial de las órbitas caóticas en un modelo autoconsistente de galaxia elíptica

    NASA Astrophysics Data System (ADS)

    Muzzio, J. C.

    Hemos logrado construir modelos autoconsistentes de sistemas estelares utilizando una aproximación cuadrupolar para el potencial. Esto nos permite determinar órbitas y exponentes de Lyapunov de objetos que tienen posiciones y velocidades equivalentes a las que se obtienen de la funcón de distribución del sistema. La distribución espacial de las órbitas caóticas exhibe considerable estructura y, lo que es más importante aún, los valores de los exponentes de Lyapunov calculados sobre intervalos finitos de tiempo, muestran una fuerte correlación con el comportamiento de la órbita en esos mismos intervalos, por lo que permiten reconocer distintos subsistemas con diferentes distribuciones espaciales.

  3. 1-Dodecane-sulfonic-acid-sodium-salt(LAS) assisted hydrothermal synthesis of CdxZn1-xS solid solution as efficient photocatalysts under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Jia, B.; Guo, L. J.

    2010-03-01

    With anionic surfactant LAS assisted, series of zinc cadmium sulfide semiconductor photocatalysts were synthesized by hydrothermal method. These products were characterized by X-ray diffraction (XRD), UV-Vis absorption spectra (UV-Vis) and scanning electron microscopy (FESEM). The photocatalytic activities of as-prepared samples were evaluated by photocatalytic hydrogen production from water under visible-light irradiation. The best synthesis parameters are: Composition 0.9:0.1 (Cd:Zn molar ratio), Temperature 160 °C, Hydrothermal Time 48 Hour, LAS Concentration 1.7 mmol/L, the maximum visible-light-catalytic hydrogen production rate is 161.25 μmol/h (λ>430 nm) which is higher than those of by coprecipitation method. The experiment results indicate that surfactant assisted hydrothermal method is an effective way to get highly active CdZnS solid solution photocatalyst.

  4. Geologic and geophysical maps of the Las Vegas 30' x 60' quadrangle, Clark and Nye counties, Nevada, and Inyo County, California

    USGS Publications Warehouse

    Page, William R.; Lundstrom, Scott C.; Harris, Anita G.; Langenheim, V.E.; Workman, Jeremiah B.; Mahan, Shannon; Paces, James B.; Dixon, Gary L.; Rowley, Peter D.; Burchfiel, B.C.; Bell, John W.; Smith, Eugene I.

    2005-01-01

    Las Vegas and Pahrump are two of the fastest growing cities in the US, and the shortage of water looms as among the greatest future problems for these cities. These new maps of the Las Vegas 30 x 60-minute quadrangle provide a geologic and geophysical framework and fundamental earth science database needed to address societal issues such as ground water supply and contamination, surface flood, landslide, and seismic hazards, and soil properties and their changing impact by and on urbanization. The mountain ranges surrounding Las Vegas and Pahrump consist of Mesozoic, Paleozoic and Proterozoic rocks. A majority of these rocks are Paleozoic carbonate rocks that are part of Nevada's carbonate rock aquifer province. The Spring Mountains represent a major recharge site in the province, where maximum altitude is 3,632 m (Charleston Peak) above sea level. Rocks in the Sheep and Las Vegas Ranges and Spring Mountains contain correlative, northeast-striking, southeast-verging thrust faults that are part of the Cretaceous, Sevier orogenic belt. These thrusts were offset during the Miocene by the Las Vegas Valley shear system (LVVSZ). We conducted new mapping in the Blue Diamond area, highlighting refined work on the Bird Spring thrust, newly studied ancient landslides, and gravity-slide blocks. We conducted new mapping in the Las Vegas Range and mapped previously unrecognized structures such as the Valley thrust and fold belt; recognition of these structures has led to a refined correlation of Mesozoic thrust faults across the LVVSZ. New contributions in the quadrangle also include a greatly refined stratigraphy of Paleozoic bedrock units based on conodont biostragraphy. We collected over 200 conodont samples in the quadrangle and established stratigraphic reference sections used to correlate units across the major Mesozoic thrust faults. Quaternary deposits cover about half of the map area and underlie most of the present urbanized area. Deposits consist of large coalescing

  5. Use of isotopic data to evaluate recharge and geologic controls on the movement of ground water in Las Posas Valley, Ventura County, California

    USGS Publications Warehouse

    Izbicki, John A.; Martin, Peter

    1997-01-01

    Injection, storage, and recovery of imported water is planned for aquifers underlying Las Posas Valley. To evaluate sources of ground-water recharge and the age of the water (time since recharge), and to identify barriers to ground-water flow prior to the injection of imported water, samples from wells and surface sources were collected and analyzed for chemical and isotopic composition. The delta oxygen- 18 and delta deuterium composition in almost 50 samples from 32 wells ranged from -6.0 to -7.9 per mil, and -40 to -60 per mil, respectively; and in 13 samples of surface water at 6 sites the composition ranged from -6.2 to -9.4 per mil, and -42 to -71 per mil, respectively. Water from wells in the upper aquifer system near Arroyo Simi and Arroyo Las Posas (different reaches of the same stream) was isotopi cally lighter than water from other wells sampled and was similar in isotopic composition to water in the stream. Water in the stream is a mixture of local water and imported water from northern California that was discharged to the stream as treated municipal wastewater. Water from wells near the stream contained tritium and, therefore, was recharged less than 50 years ago. Water from wells in other parts of the valley was isotopically heavier, did not contain tritium, and, therefore, was recharged more than 50 years ago. Interpreted carbon-14 ages for water from wells along a flow path through the valley ranged from at least 800 to more than 8,000 years before present. There were large differences in the chemistry, isotopic composition, and interpreted age of water from wells between the eastern and western parts of Las Posas Valley. These changes are consistent with geologic and hydrologic data that suggest the presence of a barrier to ground-water flow between east and west Las Posas Valley.

  6. American Recovery and Reinvestment Act (ARRA) FEMP Technical Assistance Federal Aviation Administration Project 209 - Control Tower and Support Building, Las Vegas, NV

    SciTech Connect

    Arends, J.; Sandusky, William F.

    2010-03-31

    This report represents findings of a design review team that evaluated construction documents (at the 70% level) and operating specifications for a new control tower and support building that will be built in Las Vegas, Nevada by the Federal Aviation Administration (FAA). The focus of the review was to identify measures that could be incorporated into the final design and operating specification that would result in additional energy savings for the FAA that would not have otherwise occurred.

  7. Ground-water conditions in Las Vegas Valley, Clark County, Nevada; Part 2, Hydrogeology and simulation of ground-water flow

    USGS Publications Warehouse

    Morgan, David S.; Dettinger, Michael D.

    1996-01-01

    In sedimentary deposits beneath arid Las Vegas Valley, ground-water levels have declined as much as 280 feet since 1912 in deeper aquifers due to pumping associated with urban development. Accompanying land subsidence has been as great as 5 feet. Predictive simulations show that by maintaining pumpage and recharge at 1980 levels and using municipal wells only during periods of peak water demand, rates of water-level decline and land subsidence will be reduced.

  8. New 40Ar/39Ar isotopic dates from Miocene volcanic rocks in the Lake Mead area and southern Las Vegas Range, Nevada

    USGS Publications Warehouse

    Harlan, S.S.; Duebendorfer, E.M.; Deibert, J.E.

    1998-01-01

    New 40Ar/39Ar dates on volcanic rocks interlayered with synextensional Miocene sedimentary rocks in the western Lake Mead area and southern end of the Las Vegas Range provide tight constraints on magmatism, basin formation, and extensional deformation in the Basin and Range province of southern Nevada. Vertical axis rotations associated with movement along the Las Vegas Valley shear zone occurred after 15.67??0.10 Ma (2??), based on a 40Ar/39Ar date from a tuff in the Gass Peak formation in the southern Las Vegas Range. Basaltic magmatism in the western Lake Mead area began as early as 13.28??0.09 Ma, based on a date from a basalt flow in the Lovell Wash Member of the Horse Spring Formation. Isotopic dating of a basalt from the volcanic rocks of Callville Mesa indicates that these rocks are as old as 11.41??0.14 Ma, suggesting that volcanic activity began shortly after formation of the Boulder basin, the extensional basin in which the informally named red sandstone unit was deposited. The red sandstone unit is at least as old as 11.70??0.08 Ma and contains megabreccia deposits younger than 12.93??0.10 Ma. This results shows that formation of the Boulder basin was associated with development of topographic relief that was probably generated by movement along the Saddle Island low-angle normal fault. Stratal tilting associated with extension occurred both prior to and after 11.5 Ma.

  9. A Tale of two Cities: Photoacoustic and Aethalometer Measurements Comparisons of Light Absorption in Mexico City and Las Vegas, NV, USA

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Marley, N. A.; Gaffney, J. S.

    2007-05-01

    As part of the Megacity Impacts on Regional and Global Environments, MIRAGE-Mex deployment to Mexico City in the period of 30 days, March 2006, a suite of photoacoustic spectrometers (PAS; W. Arnott & G. Paredes), nephelometer scattering, and aetholemeter absorption instruments (N. Marley & J.Gaffney) were installed to measure at ground level the light absorption and scattering by aerosols at the urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). This IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed. The Las Vegas, NV site was located at East Charleston Street on January-February, 2003. In east Las Vegas typical westerly winds carry the city plume across the site. Comparisons of PAS aerosol light absorption and aetholemeter absorption measurements at 521 nm at both Las Vegas NV and Mexico City sites will be presented. We will also present a broad overview of the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the sites in relation to secondary aerosol formation.

  10. Analysis of impacts of urban land use and land cover on air quality in the Las Vegas region using remote sensing information and ground observations

    USGS Publications Warehouse

    Xian, G.

    2007-01-01

    Urban development in the Las Vegas Valley of Nevada (USA) has expanded rapidly over the past 50 years. The air quality in the valley has suffered owing to increases from anthropogenic emissions of carbon monoxide, ozone and criteria pollutants of particular matter. Air quality observations show that pollutant concentrations have apparent heterogeneous characteristics in the urban area. Quantified urban land use and land cover information derived from satellite remote sensing data indicate an apparent local influence of urban development density on air pollutant distributions. Multi‐year observational data collected by a network of local air monitoring stations specify that ozone maximums develop in the May and June timeframe, whereas minimum concentrations generally occur from November to February. The fine particulate matter maximum occurs in July. Ozone concentrations are highest on the west and northwest sides of the valley. Night‐time ozone reduction contributes to the heterogeneous features of the spatial distribution for average ozone levels in the Las Vegas metropolitan area. Decreased ozone levels associated with increased urban development density suggest that the highest ozone and lowest nitrogen oxides concentrations are associated with medium to low density urban development in Las Vegas.

  11. Perspectivas para mejorar la salud sexual de las minorías sexuales y de identidad de género en Guatemala

    PubMed Central

    Alonzo, Jorge; Mann, Lilli; Simán, Florence; Sun, Christina J.; Andrade, Mario; Villatoro, Guillermo; Rhodes, Scott D.

    2016-01-01

    Resumen Las minorías sexuales y de identidad de género en Guatemala son afectadas de manera desproporcionada por el VIH y otras infecciones transmitidas sexualmente (ITS). Sin embargo, poco se sabe de los factores que contribuyen al riesgo de infección en estas minorías. Investigadores de Estados Unidos y Guatemala quisimos informarnos sobre las necesidades de salud sexual e identificar características de programas de prevención de VIH/ITS para estas minorías. Llevamos a cabo 8 grupos focales con hombres gay, bisexuales y personas transgénero y entrevistas en profundidad con líderes comunitarios. Utilizamos el Método Comparativo Constante para analizar las transcripciones. Identificamos 24 factores que influyen en la salud sexual y 16 características de programas para reducir el riesgo de VIH/ITS en estas poblaciones. La identificación de factores de conductas sexuales de riesgo y de características de programas potencialmente efectivos ofrece gran potencial para desarrollar intervenciones que contribuyan a reducir el riesgo de infección por VIH/ITS en estas minorías en Guatemala. PMID:27494000

  12. Conceptuaciones de los estudiantes de las facultades de educacion y ciencias naturales de la Universidad de Puerto Rico, recinto de Rio Piedras, acerca de la ciencia y la pseudociencia

    NASA Astrophysics Data System (ADS)

    Reyes Medina, Hector A.

    Esta investigacion describe las conceptuaciones de los estudiantes de tercer ano o mas a nivel de bachillerato de los programas de Educacion en Ciencia y Ciencias Naturales de la Universidad de Puerto Rico, Recinto de Rio Piedras, acerca de lo establecido en la literatura para distinguir el conocimiento cientifico de las creencias pseudocientificas. Este estudio se guio por un diseno tipo encuesta transversal que permitio conocer de manera consistente las conceptuaciones de los estudiantes encuestados acerca de la Ciencia y la Pseudociencia. Ademas, permitio desarrollar inferencias estadisticas relacionadas a la poblacion de estudio, sus conceptuaciones y su inclinacion teorica en torno al Realismo y al Racionalismo cientifico moderados. El instrumento utilizado fue el Cuestionario acerca de las concepciones de la ciencia y la pseudocienca en estudiantes universitarios, Reyes (2015). Este cuestionario fue validado mediante la recopilacion de diversas fuentes de evidencias, entre estas se encuentran las evidencias basadas en el contenido, el proceso de respuesta, la estructura interna y de constructo. Tambien, se calculo el Alfa de Crombach para la escala total y para cada componente y se realizo un analisis de factores que demostro la presencia de seis componentes claramente definidos de acuerdo a lo esperado sobre las caracteristicas originales del instrumento. Las estadisticas utilizadas fueron descriptivas. Participaron 302 alumnos, de las facultades de educacion y ciencias naturales. Se encontro que las conceptuaciones de los estudiantes de ambas facultades se inclinan en un 66.2% a favor con lo establecido en el modelo teorico en torno al Realismo y al Racionalismo cientifico moderados. Sin embargo, aun hay un 33.8% de los estudiantes de ambas facultades que poseen conceptuaciones distintas al modelo teorico propuesto.

  13. Degradación de Marismas Costera: el Impacto de la Eutrofización en la Supervivencia del las Marismas Costeras en New England y Central California, USA. (Salt Marsh Deterioration in New England and Central California: Impacts of Eutrophication on Salt Marsh Survival.)

    EPA Science Inventory

    Las marismas costeras proporcionan numerosos beneficios a los ecosistemas, incluyendo la proporción del hábitat de la flora y fauna, la protección de las zonas costeras contra inundaciones durante eventos extremos, mejoran la calidad del agua para las almejas y ostras a través de...

  14. Real-Time Access to Altimetry and Operational Oceanography Products via OPeNDAP/LAS Technologies : the Example of Aviso, Mercator and Mersea Projects

    NASA Astrophysics Data System (ADS)

    Baudel, S.; Blanc, F.; Jolibois, T.; Rosmorduc, V.

    2004-12-01

    The Products and Services (P&S) department in the Space Oceanography Division at CLS is in charge of diffusing and promoting altimetry and operational oceanography data. P&S is so involved in Aviso satellite altimetry project, in Mercator ocean operational forecasting system, and in the European Godae /Mersea ocean portal. Aiming to a standardisation and a common vision and management of all these ocean data, these projects led to the implementation of several OPeNDAP/LAS Internet servers. OPeNDAP allows the user to extract via a client software (like IDL, Matlab or Ferret) the data he is interested in and only this data, avoiding him to download full information files. OPeNDAP allows to extract a geographic area, a period time, an oceanic variable, and an output format. LAS is an OPeNDAP data access web server whose special feature consists in the facility for unify in a single vision the access to multiple types of data from distributed data sources. The LAS can make requests to different remote OPeNDAP servers. This enables to make comparisons or statistics upon several different data types. Aviso is the CNES/CLS service which distributes altimetry products since 1993. The Aviso LAS distributes several Ssalto/Duacs altimetry products such as delayed and near-real time mean sea level anomaly, absolute dynamic topography, absolute geostrophic velocities, gridded significant wave height and gridded wind speed modulus. Mercator-Ocean is a French operational oceanography centre which distributes its products by several means among them LAS/OPeNDAP servers as part of Mercator Mersea-strand1 contribution. 3D ocean description (temperature, salinity, current and other oceanic variables) of the North Atlantic and Mediterranean are real-time available and weekly updated. LAS special feature consisting in the possibility of making requests to several remote data centres with same OPeNDAP configurations particularly fitted to Mersea strand-1 problematics. This European

  15. Analysis of Individual Carbonaceous Particles Emitted from the Las Conchas Wildfire, Los Alamos, NM, in June-July 2011

    NASA Astrophysics Data System (ADS)

    Mazzoleni, C.; China, S.; Gorkowski, K.; Flowers, B. A.; Aiken, A. C.; Dubey, M. K.

    2012-12-01

    Carbonaceous aerosol emitted from biomass burning contributes significantly to atmospheric aerosol loadings regionally and globally. The net direct radiative forcing of biomass burning aerosol can be positive and/or negative and this depends on its composition, morphology and mixing state. Biomass burning aerosols can also change the cloud properties as they can act as cloud condensation nuclei. In this study we investigated biomass burning particles emitted from the Las Conchas wildfire in northern New Mexico that started on June 26, 2011 and burned an area of 245 square miles. Aerosol samples were collected on nucleopore filters at the Los Alamos National Laboratory during the third week of the wildfire event. Individual particles (~4000) were investigated using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) to distinguish different carbonaceous particles and their shape, size, elemental composition and mixing state. A thermo-denuder was used to remove compounds that are volatile at temperatures up to 200 C, leaving behind the black carbon and any compounds that did not volatize completely. Smoke particles consisted of a) tar balls, which are amorphous spherical carbonaceous organic aerosols; b) organic particles with inorganic inclusions, c) soot particles and (d) soot with various inclusions. Two distinct kinds of tar balls, "electronically" dark and bright, were found using the field-emission scanning electron microscopy and were characterized for ambient and denuded conditions to understand coating effects and aging. It was found that dark tar balls are generally larger in size than the bright ones. Additionally, the difference between the size of ambient-bright and the size of denuded-bright tar balls was larger than the difference between the size of ambient-dark and the size of denuded-dark tar balls. EDS analysis showed that 70% of the dark tar balls had higher (~60%) relative oxygen content than in the bright

  16. Fluid inclusion studies of the Rodeo de Los Molles REE and Th deposit, Las Chacras Batholith, Central Argentina

    NASA Astrophysics Data System (ADS)

    Lira, Raul; Ripley, Edward M.

    1990-03-01

    The Rodeo de Los Molles rare earth element (REE) and thorium deposit is located in granitic rocks of the Las Chacras-Piedras Coloradas Batholith, in the southern block of the Eastern Pampean Ranges, Central Argentina. Mineralization occurs within an elongate (2 km × 0.6 km) body of alkalifeldspar granite (alaskite) localized along the northeastern edge of a composite batholith. The surrounding lithology is predominantly a biotite monzogranite. Both the alaskite and localized areas of quartz alkalifeldspar syenite within the alaskite have been produced by hydrothermal alteration of a late-crystallizing phase of the monzogranite. REE minerals are primarily of the cerium group and include britholite and allanite, both partially replaced by bastnaesite or thorbastnaesite. These minerals occur as nodules with quartz, fluorite, aegirine-augite, sphene, and Fe-Ti oxides within aplitic to pegmatoidal quartz alkalifeldspar syenite. Uranothorite, along with a second generation of fluorite and minor amounts of MnBa oxides, occurs in the alaskite as nodules, or within quartz-lined miarolitic cavities, but is not found with the Ce-mineralization. Studies of fluid inclusions contained in quartz and fluorite indicate a complex history of open-system fluid migration and interaction with monzogranite host rocks. Fluids responsible for REE mineralization and quartz deposition, along with initial alteration of the monzogranite to alaskite and quartz alkalifeldspar syenite, were of relatively high temperature (T h of fluid inclusions in quartz = 356-535°C) and moderate salinity (15-25 eq. wt% NaCl). Mixed CO 2H 2O fluids (XCO 2 = .13-.07) found as both primary and secondary inclusions within fluorite are representative of fluids involved in the replacement of britholite-allanite by bastnaesite and sphene, aegirine-augite, and plagioclase by calcite. Minimum pressures of mineral deposition estimated from H 2OCO 2NaCl phase relations range from 1 to 2 kbars. Secondary

  17. Two enzymes of a complete degradation pathway for linear alkylbenzenesulfonate (LAS) surfactants: 4-sulfoacetophenone Baeyer-Villiger monooxygenase and 4-sulfophenylacetate esterase in Comamonas testosteroni KF-1.

    PubMed

    Weiss, Michael; Denger, Karin; Huhn, Thomas; Schleheck, David

    2012-12-01

    Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C(4)-SPC). Second, these SPCs are mineralized. 3-C(4)-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C(4)-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria.

  18. First records of Canis dirus and Smilodon fatalis from the late Pleistocene Tule Springs local fauna, upper Las Vegas Wash, Nevada.

    PubMed

    Scott, Eric; Springer, Kathleen B

    2016-01-01

    Late Pleistocene groundwater discharge deposits (paleowetlands) in the upper Las Vegas Wash north of Las Vegas, Nevada, have yielded an abundant and diverse vertebrate fossil assemblage, the Tule Springs local fauna (TSLF). The TSLF is the largest open-site vertebrate fossil assemblage dating to the Rancholabrean North American Land Mammal Age in the southern Great Basin and Mojave Desert. Over 600 discrete body fossil localities have been recorded from the wash, including an area that now encompasses Tule Springs Fossil Beds National Monument (TUSK). Paleowetland sediments exposed in TUSK named the Las Vegas Formation span the last 250 ka, with fossiliferous sediments spanning ∼100-13 ka. The recovered fauna is dominated by remains of Camelopsand Mammuthus, and also includes relatively common remains of extinct Equusand Bisonas well as abundant vertebrate microfaunal fossils. Large carnivorans are rare, with only Puma concolor and Panthera atrox documented previously. Postcranial remains assigned to the species Canis dirus (dire wolf) and Smilodon fatalis (sabre-toothed cat) represent the first confirmed records of these species from the TSLF, as well as the first documentation of Canis dirus in Nevada and the only known occurrence of Smilodonin southern Nevada. The size of the recovered canid fossil precludes assignment to other Pleistocene species of Canis. The morphology of the felid elements differentiates them from other large predators such as Panthera, Homotherium, and Xenosmilus, and the size of the fossils prevents assignment to other species of Smilodon. The confirmed presence of S. fatalis in the TSLF is of particular interest, indicating that this species inhabited open habitats. In turn, this suggests that the presumed preference of S. fatalis for closed-habitat environments hunting requires further elucidation.

  19. Las Alpujarras region (South East Spain) HLA genes study: evidence of a probable success of 17th century repopulation from North Spain.

    PubMed

    Longás, Javier; Martínez-Laso, Jorge; Rey, Diego; Areces, Cristina; Casado, Eduardo Gómez; Parga-Lozano, Carlos; Luna, Francisco; de Salamanca, Mercedes Enriquez; Moral, Pedro; Arnaiz-Villena, Antonio

    2012-02-01

    Conquest of Granada Muslim Kingdom (1492 AD) finished with Muslim occupation; they were mostly North African Berbers who had reached Iberia by 711 AD. A politics of Iberian Christianization followed after this date: Jewish were expelled in 1492 and Moriscos (Spaniards practicing Muslim religion or speaking Arab) were expelled from all Spanish territory on 1609 AD. Las Alpujarras is a southern Spain mountainous secluded region, which underwent a repopulation from North Spain and a specific Muslim (Moriscos)-Christian war took place according to historical records. Both Las Alpujarras repopulation by northern Iberians and Moriscos expulsion success have been debated and are regarded as non-clarified episodes. In this study, we have addressed the question whether the repopulation succeeded by determining HLA genes of present day Las Alpujarras inhabitants and compared with those of other Mediterranean populations HLA frequencies and genealogies. HLA frequencies show ambiguous results because of extant HLA similar gene frequencies there exist in North Africa and Spain. This is reflected by the finding of North and South western Mediterraneans close relatedness of HLA dendrograms and correspondence analyses. However, the genealogical study of extended HLA haplotypes particularly Alpujarran high frequency of HLA-A29-B44-DRB1*0701-DQA1*02-DQB1*02 (not found in Algerians but frequent in North and Central Spain) and Alpujarran low frequency extended haplotype HLA-A3-B7-DRB1*1501-DQA1*0102-DQB1*0602 (frequent in North Europe) reveals that a significant HLA gene flow from North Spain is observed in present day Alpujarrans: both haplotypes are characteristic of North Spain and North Europe, respectively. This may indicate that enforced Alpujarran repopulation from North Spain may have been a success, which was started by Spanish King Philip II in 1571 AD.

  20. First records of Canis dirus and Smilodon fatalis from the late Pleistocene Tule Springs local fauna, upper Las Vegas Wash, Nevada

    PubMed Central

    Springer, Kathleen B.

    2016-01-01

    Late Pleistocene groundwater discharge deposits (paleowetlands) in the upper Las Vegas Wash north of Las Vegas, Nevada, have yielded an abundant and diverse vertebrate fossil assemblage, the Tule Springs local fauna (TSLF). The TSLF is the largest open-site vertebrate fossil assemblage dating to the Rancholabrean North American Land Mammal Age in the southern Great Basin and Mojave Desert. Over 600 discrete body fossil localities have been recorded from the wash, including an area that now encompasses Tule Springs Fossil Beds National Monument (TUSK). Paleowetland sediments exposed in TUSK named the Las Vegas Formation span the last 250 ka, with fossiliferous sediments spanning ∼100–13 ka. The recovered fauna is dominated by remains of Camelopsand Mammuthus, and also includes relatively common remains of extinct Equusand Bisonas well as abundant vertebrate microfaunal fossils. Large carnivorans are rare, with only Puma concolor and Panthera atrox documented previously. Postcranial remains assigned to the species Canis dirus (dire wolf) and Smilodon fatalis (sabre-toothed cat) represent the first confirmed records of these species from the TSLF, as well as the first documentation of Canis dirus in Nevada and the only known occurrence of Smilodonin southern Nevada. The size of the recovered canid fossil precludes assignment to other Pleistocene species of Canis. The morphology of the felid elements differentiates them from other large predators such as Panthera, Homotherium, and Xenosmilus, and the size of the fossils prevents assignment to other species of Smilodon. The confirmed presence of S. fatalis in the TSLF is of particular interest, indicating that this species inhabited open habitats. In turn, this suggests that the presumed preference of S. fatalis for closed-habitat environments hunting requires further elucidation. PMID:27366649

  1. Two Enzymes of a Complete Degradation Pathway for Linear Alkylbenzenesulfonate (LAS) Surfactants: 4-Sulfoacetophenone Baeyer-Villiger Monooxygenase and 4-Sulfophenylacetate Esterase in Comamonas testosteroni KF-1

    PubMed Central

    Weiss, Michael; Denger, Karin; Huhn, Thomas

    2012-01-01

    Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C4-SPC). Second, these SPCs are mineralized. 3-C4-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C4-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria. PMID:23001656

  2. Does the spatial arrangement of vegetation and anthropogenic land cover features matter? Case studies of urban warming and cooling in Phoenix and Las Vegas

    NASA Astrophysics Data System (ADS)

    Myint, S. W.; Zheng, B.; Fan, C.; Kaplan, S.; Brazel, A.; Middel, A.; Smith, M.

    2014-12-01

    While the relationship between fractional cover of anthropogenic and vegetation features and the urban heat island has been well studied, the effect of spatial arrangements (e.g., clustered, dispersed) of these features on urban warming or cooling are not well understood. The goal of this study is to examine if and how spatial configuration of land cover features influence land surface temperatures (LST) in urban areas. This study focuses on Phoenix, AZ and Las Vegas, NV that have undergone dramatic urban expansion. The data used to classify detailed urban land cover types include Geoeye-1 (Las Vegas) and QuickBird (Phoenix). The Geoeye-1 image (3 m resolution) was acquired on October 12, 2011 and the QuickBird image (2.4 m resolution) was taken on May 29, 2007. Classification was performed using object based image analysis (OBIA). We employed a spatial autocorrelation approach (i.e., Moran's I) that measures the spatial dependence of a point to its neighboring points and describes how clustered or dispersed points are arranged in space. We used Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data acquired over Phoenix (daytime on June 10, 2011 and nighttime on October 17, 2011) and Las Vegas (daytime on July 6, 2005 and nighttime on August 27, 2005) to examine daytime and nighttime LST with regards to the spatial arrangement of anthropogenic and vegetation features. We spatially correlate Moran's I values of each land cover per surface temperature, and develop regression models. The spatial configuration of grass and trees shows strong negative correlations with LST, implying that clustered vegetation lowers surface temperatures more effectively. In contrast, a clustered spatial arrangement of anthropogenic land-cover features, especially impervious surfaces, significantly elevates surface temperatures. Results from this study suggest that the spatial configuration of anthropogenic and vegetation features influence urban warming and cooling.

  3. First records of Canis dirus and Smilodon fatalis from the late Pleistocene Tule Springs local fauna, upper Las Vegas Wash, Nevada

    USGS Publications Warehouse

    Scott, Eric; Springer, Kathleen

    2016-01-01

    Late Pleistocene groundwater discharge deposits (paleowetlands) in the upper Las Vegas Wash north of Las Vegas, Nevada, have yielded an abundant and diverse vertebrate fossil assemblage, the Tule Springs local fauna (TSLF). The TSLF is the largest open-site vertebrate fossil assemblage dating to the Rancholabrean North American Land Mammal Age in the southern Great Basin and Mojave Desert. Over 600 discrete body fossil localities have been recorded from the wash, including an area that now encompasses Tule Springs Fossil Beds National Monument (TUSK). Paleowetland sediments exposed in TUSK named the Las Vegas Formation span the last 250 ka, with fossiliferous sediments spanning ∼100–13 ka. The recovered fauna is dominated by remains of Camelopsand Mammuthus, and also includes relatively common remains of extinct Equusand Bisonas well as abundant vertebrate microfaunal fossils. Large carnivorans are rare, with only Puma concolor and Panthera atrox documented previously. Postcranial remains assigned to the species Canis dirus (dire wolf) and Smilodon fatalis(sabre-toothed cat) represent the first confirmed records of these species from the TSLF, as well as the first documentation of Canis dirus in Nevada and the only known occurrence of Smilodonin southern Nevada. The size of the recovered canid fossil precludes assignment to other Pleistocene species of Canis. The morphology of the felid elements differentiates them from other large predators such as Panthera, Homotherium, and Xenosmilus, and the size of the fossils prevents assignment to other species of Smilodon. The confirmed presence of S. fatalis in the TSLF is of particular interest, indicating that this species inhabited open habitats. In turn, this suggests that the presumed preference of S. fatalis for closed-habitat environments hunting requires further elucidation.

  4. Phenotypical and genetic characterization of Trichosporon sp. HP-2023. A yeast isolate from Las Yungas rainforest (Tucumán, Argentina) with dye-decolorizing ability.

    PubMed

    Pajot, Hipólito F; Figueroa, Lucía I C; Spencer, John F T; Fariña, Julia I

    2008-08-01

    A basidiomycetous yeast isolated from Las Yungas rainforest (Tucumán, Argentina) and arbitrarily named HP-2023 was selected based on its outstanding textile dye decolorizing ability. Complete decolorization of Vilmafix Red 7B-HE and Vilmafix Blue RR-BB (200 mg/l) was achieved after 16 h of cultivation. Yeast characterization was accomplished by means of both traditional and molecular methods. Results concerning molecular fingerprinting and phenotypic characterization led to identify it as Trichosporon sp., closely related to the T. multisporum-T. laibachii complex. The present work represents the first description of a Trichosporon yeast involved in reactive textile dye decolorization processes.

  5. The Armed Forces and the Fight against Drug-Trafficking in Honduras (Las FUERZAS ARMADAS EN EL COMBATE AL NARCOTR FICO EN HONDURAS)

    DTIC Science & Technology

    2013-06-13

    estén abrumados, por su propia solicitud . Nuestra Constitución prevé que la Policía Nacional pueda otorgar poderes a nuestras Fuerzas Armadas, a pedido...aprovechado desde el punto de vista que le dan empleo con altas 1Secretaría de Defensa de Honduras, Libro Blanco de la Defensa Nacional Tegucigalpa...comprensible dado que las solicitudes se han realizado a la distancia. Delimitaciones La investigación cubre aspectos e incidentes en particular de

  6. Gaseous Mercury Monitoring at a Complex Source: The Las Cuevas Decommissioned Mining Complex and Current Hg Storage Facility (Almadén District, Spain)

    NASA Astrophysics Data System (ADS)

    Higueras, P. L.; Esbri, J. M.; Llanos, W. R.; Oyarzun, R.; Martinez-Coronado, A.; Grupo de Estudios En Minería Y Medioambiente-Gemm

    2010-12-01

    The Las Cuevas decommissioned mining complex was the third in importance in the world’s largest mercury mining district: Almadén (south-central Spain). Mining took place during two well differentiated periods: 1. Roman time; and 2. From 1982 to 2000. In 2004 the mine was transformed into a mercury storage and handling facility, away from urban areas. Furthermore, the area served as a test site for the design and implementation of a mercury safe storage vessel, a study funded by European LIFE-Env programme (Project MERSADE, LIFE06 ENV/ES/PREP/03) (Llanos et al., 2010). On this basis, Las Cuevas site can be regarded as a complex source of atmospheric mercury for the local environmental compartments, including emissions from the plant activity, partly reclamated old mineral dumps, contaminated soils, and other minor sources, such as cavities produced by mine collapse. We studied the emissions with two LUMEX RA-915+ Hg analyzers, one LUMEX RA-915Light device and a complete TEKRAN equipment, including Mercury Speciation Unit (model 1130) and Particulate Mercury Unit (Model 1135). Data has been treated with ISC-AERMOD program, in order to obtain models for contamination plumes derived from Las Cuevas whole area. The results confirm the mercury storage facility as the main local source for mercury, releasing some 3,15 kg Hg y-1, whereas contaminated soils and reclamated dumps represent local minor sources. Over 99,9% of local atmospheric mercury is Gaseous Elemental Mercury, with Reactive Gaseous Mercury representing 0,25 per mil, and particulate bound mercury, 1,8 per mil. Citation: Llanos, W.; Higueras, P.; Oyarzun, R.; Esbrí, J.M.; López-Berdonces, M.A.; García-Noguero, E.M.; Martínez-Coronado, A. (2010) A preliminary environmental assessment at the site of the European prototype installation of a safe deposit for surplus mercury from industry: The Las Cuevas mining complex, Almadén District, Spain. Science of the Total Environment, 408: 4901-4905.

  7. Evaluation of S-101 course Supervisors' Orientation to Occupational Safety in DOE'' taught in Las Vegas, Nevada, October 26--29, 1992

    SciTech Connect

    Wright, T.S.

    1993-03-01

    This report summarizes trainee evaluations for the Safety Training Section course, Supervisors' Orientation to Occupational Safety in DOE'', (S-101) which was conducted October 26--29, 1992 at EG G Measurement, in Las Vegas, Nevada. Sections 1.1 and 1.2 of this report summarize the quantitative course evaluations that trainees provided upon completion of the course. Sections 2.0 and 3.0 provide examination results, and recommendations for improvement. Appendix A provides a transcript of the trainees' written comments and Appendix B presents a copy of the course evaluation form that students were asked to complete.

  8. Evaluation of S-101 course ``Supervisors` Orientation to Occupational Safety in DOE`` taught in Las Vegas, Nevada, October 26--29, 1992

    SciTech Connect

    Wright, T.S.

    1993-03-01

    This report summarizes trainee evaluations for the Safety Training Section course, ``Supervisors` Orientation to Occupational Safety in DOE``, (S-101) which was conducted October 26--29, 1992 at EG&G Measurement, in Las Vegas, Nevada. Sections 1.1 and 1.2 of this report summarize the quantitative course evaluations that trainees provided upon completion of the course. Sections 2.0 and 3.0 provide examination results, and recommendations for improvement. Appendix A provides a transcript of the trainees` written comments and Appendix B presents a copy of the course evaluation form that students were asked to complete.

  9. Evapotranspiration of Mixed Shrub Communities in Phreatophytic Zones of the Great Basin D.A. Devitt1, L.K. Fenstermaker2, M. Young2, B. Conrad1 and B. Bird1 1 School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 2 Desert Research Institute, Las Vegas, NV

    NASA Astrophysics Data System (ADS)

    Devitt, D. A.; Fenstermaker, L. K.; Young, M.; Conrad, B.; Bird, B.

    2009-12-01

    Water limitations in the arid and semiarid regions of the southwestern United States have led many water managers of municipalities to begin the process of diversifying their water resource portfolios. Las Vegas in particular, is pursuing groundwater exportation from east central basins in Nevada. Estimating evapotranspiration (ET) is a critical component to closing hydrologic balances in these basins. As such, ET was estimated for three valleys in the Great Basin Region of Nevada (USA) during a three year period. ET estimates were made based on an energy balance approach using the eddy covariance method. ET estimates at the basin scale were made by developing empirical relationships between ET and remotely sensed spectral data (Landsat). Groundwater, soil moisture, rainfall and leaf level measurements were used to validate the differences in ET estimates based on site, year and basin. When the ET correlations were based on average NDVI values during the growing period and incorporated previously published values attained for the same valleys during the same time period, we could account for 97% of the variation in the ET estimate for the May 10 to September 5 growing period and 93% of the variation in the ET estimates based on measured or projected yearly ET totals. Variations in yearly ET estimates at the different shrub and grassland sites ranged from 20 to 50 cm during the two dry years (2006, 2007, not including the irrigated site). The amount of winter precipitation was shown to be a significant driving force in the physiological response of the plants and the yearly ET totals. In the case of White River Valley the ratio of winter precipitation to reference evapotranspiration declined from 79% to 11% over the 3 year monitoring period. Such changes led to a direct impact on leaf xylem water potential values of greasewood (Sarcobatus vermiculatus). During the two drier years (2006 and 2007) greasewood plants entered into the growing period with lower mid day

  10. High-level nuclear waste transport and storage assessment of potential impacts on tourism in the Las Vegas area. Nevada Nuclear Waste Storage Investigations Project

    SciTech Connect

    1985-12-01

    The literature review and empirical analyses presented in this report were undertaken, for the most part, between August and October 1983. They are not comprehensive. No primary data were gathered, nor were any formal surveys conducted. Additionally, because construction of a repository at Yucca Mountain, if that site is selected for a repository, is not scheduled to begin until 1993, engineering design and planned physical appearance of the repository are very preliminary. Therefore, specific design features or visual appearance were not addressed in the analyses. Finally, because actual transportation routes have not been designated, impacts on tourism generated specifically by transportation activities are not considered separately. Chapter 2 briefly discusses possible means by which a repository could impact tourism in the Las Vegas area. Chapter 3 presents a review of previous research on alternative methods for predicting the response of people to potential hazards. A review of several published studies where these methods have been applied to facilities and activities associated with radioactive materials is included in Chapter 3. Chapter 4 contains five case studies of tourism impacts associated with past events that were perceived by the public to represent safety hazards. These perceptions of safety hazards were evidenced by news media coverage. These case studies were conducted specifically for this report. Conclusions of this preliminary analysis regarding the potential impact on tourism in the Las Vegas area of a repository at Yucca Mountain are in Chapter 5. Recommendations for further research are contained in Chapter 6.

  11. The bHLH protein ROX acts in concert with RAX1 and LAS to modulate axillary meristem formation in Arabidopsis.

    PubMed

    Yang, Fang; Wang, Quan; Schmitz, Gregor; Müller, Dörte; Theres, Klaus

    2012-07-01

    During post-embryonic shoot development, new meristems are initiated in the axils of leaves. They produce secondary axes of growth that determine morphological plasticity and reproductive efficiency in higher plants. In this study, we describe the role of the bHLH-protein-encoding Arabidopsis gene REGULATOR OF AXILLARY MERISTEM FORMATION (ROX), which is the ortholog of the branching regulators LAX PANICLE1 (LAX1) in rice and barren stalk1 (ba1) in maize. rox mutants display compromised axillary bud formation during vegetative shoot development, and combination of rox mutants with mutations in RAX1 and LAS, two key regulators of axillary meristem initiation, enhances their branching defects. In contrast to lax1 and ba1, flower development is unaffected in rox mutants. Over-expression of ROX leads to formation of accessory side shoots. ROX mRNA accumulates at the adaxial boundary of leaf and flower primordia. However, in the vegetative phase, axillary meristems initiate after ROX expression has terminated, suggesting an indirect role for ROX in meristem formation. During vegetative development, ROX expression is dependent on RAX1 and LAS activity, and all three genes act in concert to modulate axillary meristem formation.

  12. Illegal sales of cigarettes to minors--Ciudad Juárez, Mexico; El Paso, Texas; and Las Cruces, New Mexico, 1999.

    PubMed

    1999-05-21

    In 1996, the United States-Mexico Binational Commission (US-MBC) Health Working Group identified prevention of tobacco use, particularly among adolescents, as a priority and subsequently recommended joint efforts toward reducing illegal sales of cigarettes to minors. A 1997 survey of 561 commercial cigarette outlets in Mexico City found that 79% of retailers sold cigarettes to minors. To assess the illegal sale of cigarettes to minors in other regions of Mexico and on both sides of the U.S.-Mexico border, during January-February 1999 the General Directorate of Epidemiology in Mexico, the Chihuahua State Department of Health Services (CDH), the Ciudad Juarez Department of Health (CJDH), the Texas Department of Health (TDH), and the New Mexico Department of Health (NMDH) surveyed cigarette outlets in Ciudad Juarez, Mexico; El Paso, Texas; and Las Cruces, New Mexico. This report summarizes the results of these surveys, which indicate that almost all retailers in the surveyed outlets in Ciudad Juarez sold cigarettes to minors and that sales rates to minors were substantially lower in El Paso and Las Cruces.

  13. Las Islas de los Changos (the Monkey Islands): the economic impact of ecotourism in the region of Los Tuxtlas, Veracruz, Mexico.

    PubMed

    Serio-Silva, Juan Carlos

    2006-05-01

    This study evaluates the popularity and economic impact of Las Islas de los Changos (the Monkey Islands) as an ecotourism site on Lake Catemaco in the Los Tuxtlas region of Veracruz, Mexico. Two small island colonies of exotic primates, stumptail macaques (Macaca arctoides), have proved to be highly beneficial for the local economy as the main attraction for tourists in this region. From July 1991 to June 1992, data were collected on the number of tourists who took boat trips to visit the primates, and the amount of money spent on tours to the islands. The data suggest that at least 28,470 passengers visit these primate troops annually and spend approximately 88,970 U.S. dollars (USD). Follow-up questionnaires during July 1997 to June 2000 to hotelkeepers and tourist boat operators identified the Monkey Islands as the primary destination for tourists to this region. A comparison of the net income obtained by local ecotourism operators with wages earned through other types of employment in the Los Tuxtlas region, such as working in natural reserves, agriculture, or renting grazing land for cattle, show the relative importance of Las Islas de Los Changos in sustaining the local economy.

  14. Bifurcación de las soluciones de vientos impulsados por radiación en estrellas Be: formación de líneas

    NASA Astrophysics Data System (ADS)

    Curé, M.; Rial, D.; Cidale, L.; Venero, R.

    Se ha estudiado la topología de la ecuación hidrodinámica no-lineal que describe el perfil de velocidades de vientos impulsados por radiación en estrellas tempranas. Al aplicar este modelo a estrellas Be se encuentra que existen dos tipos De soluciones: la estándar, que describe el viento polar, y una nueva, que describe un viento más denso y lento y que explicaría el disco que se encuentra alrededor de estos objetos. Existe una región de transición en donde ambas soluciones coexisten (bifurcación}). Ambas soluciones satisfacen en esta región las mismas condiciones de borde. Para estas dos soluciones se han obtenido los perfiles de líneas de hidrógeno del visible y del IR, resolviendo el transporte de radiación en el ``comoving frame". Para la solución estándar, se obtienen perfiles con componentes en emisión, mientras que para la nueva solución se obtienen perfiles en absorción. Se comparan cualitativamente los resultados con las observaciones.

  15. Inverse steptoes in Las Bombas volcano, as an evidence of explosive volcanism in a solidified lava flow field. Southern Mendoza-Argentina

    NASA Astrophysics Data System (ADS)

    Risso, Corina; Prezzi, Claudia; Orgeira, María Julia; Nullo, Francisco; Margonari, Liliana; Németh, Karoly

    2015-11-01

    Here we describe the unusual genesis of steptoes in Las Bombas volcano- Llancanelo Volcanic Field (LVF) (Pliocene - Quaternary), Mendoza, Argentina. Typically, a steptoe forms when a lava flow envelops a hill, creating a well-defined stratigraphic relationship between the older hill and the younger lava flow. In the Llancanelo Volcanic Field, we find steptoes formed with an apparent normal stratigraphic relationship but an inverse age-relationship. Eroded remnants of scoria cones occur in "circular depressions" in the lava field. To express the inverse age-relationship between flow fields and depression-filled cones here we define this landforms as inverse steptoes. Magnetometric analysis supports this inverse age relationship, indicating reverse dipolar magnetic anomalies in the lava field and normal dipolar magnetization in the scoria cones (e.g. La Bombas). Negative Bouguer anomalies calculated for Las Bombas further support the interpretation that the scoria cones formed by secondary fracturing on already solidified basaltic lava flows. Advanced erosion and mass movements in the inner edge of the depressions created a perfectly excavated circular depression enhancing the "crater-like" architecture of the preserved landforms. Given the unusual genesis of the steptoes in LVF, we prefer the term inverse steptoe for these landforms. The term steptoe is a geomorphological name that has genetic implications, indicating an older hill and a younger lava flow. Here the relationship is reversed.

  16. Molecular Basis for the Recognition of Structurally Distinct Autoinducer Mimics by the Pseudomonas aeruginosa LasR Quorum-Sensing Signaling Receptor

    SciTech Connect

    Zou, Yaozhong; Nair, Satish K.

    2010-01-12

    The human pathogen Pseudomonas aeruginosa coordinates the expression of virulence factors using quorum sensing, a signaling cascade triggered by the activation of signal receptors by small-molecule autoinducers. These homoserine lactone autoinducers stabilize their cognate receptors and activate their functions as transcription factors. Because quorum sensing regulates the progression of infection and host immune resistance, significant efforts have been devoted toward the identification of small molecules that disrupt this process. Screening efforts have identified a class of triphenyl compounds that are structurally distinct from the homoserine lactone autoinducer, yet interact specifically and potently with LasR receptor to modulate quorum sensing (Muh et al., 2006a). Here we present the high-resolution crystal structures of the ligand binding domain of LasR in complex with the autoinducer N-3-oxo-dodecanoyl homoserine lactone (1.4 {angstrom} resolution), and with the triphenyl mimics TP-1, TP-3, and TP-4 (to between 1.8 {angstrom} and 2.3 {angstrom} resolution). These crystal structures provide a molecular rationale for understanding how chemically distinct compounds can be accommodated by a highly selective receptor, and provide the framework for the development of novel quorum-sensing regulators, utilizing the triphenyl scaffold.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  18. Ethnobotany and antibacterial activity of some plants used in traditional medicine of Zapotitlán de las Salinas, Puebla (México).

    PubMed

    Hernández, T; Canales, M; Avila, J G; Duran, A; Caballero, J; Romo de Vivar, A; Lira, R

    2003-10-01

    The village of Zapotitlán de las Salinas is situated in the Valley of Tehuacán-Cuicatlán, Puebla, Mexico. Plant species used by the local inhabitants to treat gastrointestinal diseases were identified using ethnobotanical, ethnographic and taxonomic methods. Out of 119 interviews, 44 plant species were registered, of which the following are the most frequently used (listed in descending order): Lippia graveolens H.B. et K. (Verbenaceae), Lantana achyranthifolia Desf. (Verbenaceae), Turnera diffusa (Willd.) ex Schult. (Turneraceae), Lippia oaxacana Rob. et Greenm. (Verbenaceae), Gymnolaena oaxacana (Greenm.) Rydb. (Asteraceae), Cordia curassavica (Jacq.) Roem. et Schult. (Boraginaceae), Lantana camara L. (Verbenaceae) and Acalypha hederacea Torrey (Euphorbiaceae). From these plants, hexane, chloroform and ethanol extracts were prepared in order to assess their antibacterial activity against 14 bacterial strains causing the most common gastrointestinal diseases in Mexican population. All hexane extracts showed antibacterial activity against Gram-positive and Gram-negative bacteria. There is a correlation between the frequency of mention (of plant use) and the antibacterial activity. In conclusion, the knowledge of plants most frequently used for gastrointestinal infections in Zapotitlán de las Salinas is supported by scientific rationale.

  19. The use of active metabolism and swimming activity to evaluate the toxicity of dodecyl benzene sodium sulfonate (LAS-C12) on the Mugil platanus (Mullet) according to temperature and salinity.

    PubMed

    Barbieri, Edison

    2007-07-01

    Active metabolism and swimming activity were used to study the effects of dodecyl benzene sodium sulfonate (LAS-C12) in Mugil platanus, a species traditionally considered as estuarine. The effects of exposure to different concentrations of LAS-C12 (0.0, 1.0, 2.5, and 5.0 mg/L) on the active metabolism and swimming activity of Mugil platanus were evaluated. The active metabolism and swimming activity were estimated through experiments conducted on each of 9 possible combinations of three temperatures (35, 20, and 15 degrees C) and three salinities (35, 20, and 5 per thousand). The results show that the active metabolism increases according to the LAS-C12 concentration in all temperatures and salinities studied. At the highest tested concentration (5.0 mg/L), the active metabolism was 111%; 84.8 and 105% higher than the control, at 35 per thousand salinity at the three temperatures. However, the swimming activity decreased according to the LAS-C12 concentration in all temperatures and salinities studied. At the highest tested concentration, the swimming activity was 78.6, 73.6, and 78.7% less than the control, at 25 degrees C at the three salinities. The active metabolism and swimming activity averages, achieved in the different salinities studied, were not significantly different, as a result of the LAS-C12 concentration.

  20. Comparing the suitability of geophysical methods in the study of a cave in marbles: A case study of Gruta de las Maravillas (Aracena, Southwest Spain)

    NASA Astrophysics Data System (ADS)

    José Martínez Moreno, Francisco; Galindo Zaldívar, Jesús; Pedrera Parias, Antonio; Ullod, Teresa Teixidó i.; Ruano Roca, Patricia; Peña Ruano, Jose Antonio; González Castillo, Lourdes; Ruiz Constan, Ana; López Chicano, Manuel; Martín Rosales, Wenceslao

    2014-05-01

    Different geophysical methods have been applied to determine the geometry of caves, considering the host rock, depth, dimension, presence of water and other parameters. The Gruta de las Maravillas cave is located in marbles interlayered with gneiss, quartzite and granodiorite along the suture between South Portuguese and Ossa Morena zone. This cave is probably formed as a consequence of the presence of pyrite and iron oxides mineralization that interacted with the surrounding marble host rocks. In order to analyze the continuity of the Gruta de las Maravillas cave (Aracena, southwest Spain) geophysical methods has been used on the known cave in order to check their suitability. These results allow investigating the prolongation of the cave in surrounding areas, performing a comprehensive study of the Cerro del Castillo hill containing the cavity. Microtopography with differential GPS and cave topography with an accuracy of 0.01 m were measured. The first geophysical method employed were a regional microgravity, with and SCINTREX CG-5 gravimeter that reaches an accuracy up to 0.001 mGal. In the obtained residual anomaly map, negative values are associated with negative density contrast, which are related to the known cave position. In addition, residual gravity minima suggest the presence of other unknown cavities. The anomalies attributed to possible new shallow and deep caves have been studied in a second step with the application of other eight detailed geophysical methods along profiles to test the response of each of them to the presence of cavities: microgravity, magnetic, electrical resistivity tomography, induced polarization, seismic P-waves velocity tomography, ray tracing coverage, common offset and ground-penetrating radar. Moreover, the known cave has walls covered with iron oxides that determine magnetic anomaly minima and intermediate resistivity values (~2000 ohm.m) on the ERT profiles versus the host marble rocks (~45000 ohm.m). After a detailed

  1. Sensing the ups and downs of Las Vegas: InSAR reveals structural control of land subsidence and aquifer-system deformation

    USGS Publications Warehouse

    Amelung, F.; Galloway, D.L.; Bell, J.W.; Zebker, H.A.; Laczniak, R.J.

    1999-01-01

    Land subsidence in Las Vegas, Nevada, United States, between April 1992 and December 1997 was measured using spaceborne interferometric synthetic aperture radar. The detailed deformation maps clearly show that the spatial extent of subsidence is controlled by geologic structures (faults) and sediment composition (clay thickness). The maximum detected subsidence during the 5.75 yr period is 19 cm. Comparison with leveling data indicates that the subsidence rates declined during the past decade as a result of rising ground-water levels brought about by a net reduction in ground-water extraction. Temporal analysis also detects seasonal subsidence and uplift patterns, which provide information about the elastic and inelastic properties of the aquifer system and their spatial variability.

  2. Environmental and geochemical record of human-induced changes in C storage during the last millennium in a temperate wetland (Las Tablas de Daimiel National Park, central Spain)

    USGS Publications Warehouse

    Dominguez-Castro, F.; Santisteban, J.I.; Mediavilla, R.; Dean, W.E.; Lopez-Pamo, E.; Gil-Garcia, M. J.; Ruiz-Zapata, M. B.

    2006-01-01

    Las Tablas de Daimiel National Park has experienced many hydrological and ecological modifications through out its history, both of natural as well as anthropogenic origin, which have affected its carbon storage capacity and carbon fluxes. The study of those variations has been carried out by the analysis of its sedimentary record (geochemistry and pollen) and historical data. The natural changes have a wider variation range than the anthropogenic ones, show repetitive patterns and the system reacts readjusting the equilibrium among its components. Anthropogenic effects depend on the direct or indirect impact on the wetlands of change and its intensity. In addition, the anthropogenic impacts have the capacity of breaking the natural balance of the ecosystem and the internal interactions. ?? 2006 The Authors Journal compilation ?? 2006 Blackwell Munksgaard.

  3. The Tangled Branches (Las Ramas Enredadas): Sexual Risk, Substance Abuse, and Intimate Partner Violence Among Hispanic Men who Have Sex with Men

    PubMed Central

    De Santis, Joseph P.; Gonzalez-Guarda, Rosa; Provencio-Vasquez, Elias; Deleon, Diego A.

    2012-01-01

    Hispanic men who have sex with men (MSM) experience a number of health disparities including high rates of HIV infection from high risk sex, substance abuse, and intimate partner violence. Although some research is available to document the relationships of these health disparities in the literature, few studies have explored the intersection of these disparities and the factors that influence them. The purpose of this study was to explore the experiences that Hispanic MSM residing in South Florida have with high risk sex, substance abuse, and intimate partner violence. Focus groups were conducted and analyzed using grounded theory methodology until data saturation was reached (n = 20). Two core categories with subcategories emerged from the data: The Roots of Risk (Los raices del riesgo) and The Tangled Branches (Las Ramas Enredadas). The results of the study provided some important clinical implications as well as directions for future research with Hispanic MSM. PMID:24084703

  4. The LasB Elastase of Pseudomonas aeruginosa Acts in Concert with Alkaline Protease AprA To Prevent Flagellin-Mediated Immune Recognition

    PubMed Central

    Casilag, Fiordiligie; Lorenz, Anne; Krueger, Jonas; Klawonn, Frank; Weiss, Siegfried

    2015-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is capable of establishing severe and persistent infections in various eukaryotic hosts. It encodes a wide array of virulence factors and employs several strategies to evade immune detection. In the present study, we screened the Harvard Medical School transposon mutant library of P. aeruginosa PA14 for bacterial factors that modulate interleukin-8 responses in A549 human airway epithelial cells. We found that in addition to the previously identified alkaline protease AprA, the elastase LasB is capable of degrading exogenous flagellin under calcium-replete conditions and prevents flagellin-mediated immune recognition. Our results indicate that the production of two proteases with anti-flagellin activity provides a failsafe mechanism for P. aeruginosa to ensure the maintenance of protease-dependent immune-modulating functions. PMID:26502908

  5. Errores sistemáticos del Catálogo Fundamental FK5, deducidos de las observaciones con Astrolabio Fotoeléctrico PAII, en el Hemisferio Sur

    NASA Astrophysics Data System (ADS)

    Manrique, W. T.; Podestá, R. C.; Alonso, E.; Actis, E. V.; Pacheco, A. M.; Bustos, G.; Lizhi, L.; Zezhi, W.; Fanmiao, Z.; Hongqi, W.; Perdomo, R.; González, A.; Gómez, G.

    Se dan los resultados obtenidos de los Errores Sistemáticos del Catálogo Fundamental FK5, Δ α δ, Δ α α, Δ δ α y Δ δ δ, derivados de las observaciones estelares con el Astrolabio Fotoeléctrico PAII del Observatorio de Beijing instalado en el Observatorio Astronómico ``Félix Aguilar'' de San Juan, de acuerdo al Proyecto de Colaboración entre los observatorios de San Juan, Beijing y La Plata. Se han usado los residuos seleccionados de 11000 estrellas aproximadamente, derivados de más de 400000 pasajes estelares en 1550 días, desde Febrero de 1992 a Marzo de 1997. La precisión media de los residuos es de 0,"043.

  6. Groundwater temperature and electrical conductivity as tools to characterize flow patterns in carbonate aquifers: The Sierra de las Nieves karst aquifer, southern Spain

    NASA Astrophysics Data System (ADS)

    Liñán Baena, C.; Andreo, B.; Mudry, J.; Carrasco Cantos, F.

    2009-06-01

    In carbonate massifs, flow patterns are conditioned by karstification processes which develop a conduit network and preserve low permeability microfractured blocks. The Sierra de las Nieves karst massif (southern Spain) is subjected to a given climatic and geological context, and thus it is possible to analyse the spatial and temporal variability of the water temperature and electrical conductivity at its main karst outlets, which display different responses to rainfall episodes. In this experimental field area, conduit flow and diffuse flow drainage patterns have been distinguished by combining groundwater temperature and electrical conductivity data. Both parameters show large variations in water coming from conduit flow systems and low variations in water drained by springs draining diffuse flow systems. However, groundwater temperature displays the smallest variations, which seems to indicate that this parameter is less sensitive as regards characterising the degree of karstification, which is a key question in characterising the aquifer functioning.

  7. Postwildfire preliminary debris flow hazard assessment for the area burned by the 2011 Las Conchas Fire in north-central New Mexico

    USGS Publications Warehouse

    Tillery, Anne C.; Darr, Michael J.; Cannon, Susan H.; Michael, John A.

    2011-01-01

    The Las Conchas Fire during the summer of 2011 was the largest in recorded history for the state of New Mexico, burning 634 square kilometers in the Jemez Mountains of north-central New Mexico. The burned landscape is now at risk of damage from postwildfire erosion, such as that caused by debris flows and flash floods. This report presents a preliminary hazard assessment of the debris-flow potential from 321 basins burned by the Las Conchas Fire. A pair of empirical hazard-assessment models developed using data from recently burned basins throughout the intermountain western United States was used to estimate the probability of debris-flow occurrence and volume of debris flows at the outlets of selected drainage basins within the burned area. The models incorporate measures of burn severity, topography, soils, and storm rainfall to estimate the probability and volume of debris flows following the fire. In response to a design storm of 28.0 millimeters of rain in 30 minutes (10-year recurrence interval), the probabilities of debris flows estimated for basins burned by the Las Conchas Fire were greater than 80 percent for two-thirds (67 percent) of the modeled basins. Basins with a high (greater than 80 percent) probability of debris-flow occurrence were concentrated in tributaries to Santa Clara and Rio del Oso Canyons in the northeastern part of the burned area; some steep areas in the Valles Caldera National Preserve, Los Alamos, and Guaje Canyons in the east-central part of the burned area; tributaries to Peralta, Colle, Bland, and Cochiti canyons in the southwestern part of the burned area; and tributaries to Frijoles, Alamo, and Capulin Canyons in the southeastern part of the burned area (within Bandelier National Monument). Estimated debris-flow volumes ranged from 400 cubic meters to greater than 72,000 cubic meters. The largest volumes (greater than 40,000 cubic meters) were estimated for basins in Santa Clara, Los Alamos, and Water Canyons, and for two

  8. The LasB Elastase of Pseudomonas aeruginosa Acts in Concert with Alkaline Protease AprA To Prevent Flagellin-Mediated Immune Recognition.

    PubMed

    Casilag, Fiordiligie; Lorenz, Anne; Krueger, Jonas; Klawonn, Frank; Weiss, Siegfried; Häussler, Susanne

    2015-10-26

    The opportunistic pathogen Pseudomonas aeruginosa is capable of establishing severe and persistent infections in various eukaryotic hosts. It encodes a wide array of virulence factors and employs several strategies to evade immune detection. In the present study, we screened the Harvard Medical School transposon mutant library of P. aeruginosa PA14 for bacterial factors that modulate interleukin-8 responses in A549 human airway epithelial cells. We found that in addition to the previously identified alkaline protease AprA, the elastase LasB is capable of degrading exogenous flagellin under calcium-replete conditions and prevents flagellin-mediated immune recognition. Our results indicate that the production of two proteases with anti-flagellin activity provides a failsafe mechanism for P. aeruginosa to ensure the maintenance of protease-dependent immune-modulating functions.

  9. The Tangled Branches (Las Ramas Enredadas): sexual risk, substance abuse, and intimate partner violence among Hispanic men who have sex with men.

    PubMed

    De Santis, Joseph P; Gonzalez-Guarda, Rosa; Provencio-Vasquez, Elias; Deleon, Diego A

    2014-01-01

    Hispanic men who have sex with men (MSM) experience a number of health disparities including high rates of HIV infection from high-risk sex, substance abuse, and intimate partner violence. Although some research is available to document the relationships of these health disparities in the literature, few studies have explored the intersection of these disparities and the factors that influence them. The purpose of this study was to explore the experiences that Hispanic MSM residing in South Florida have with high-risk sex, substance abuse, and intimate partner violence. Focus groups were conducted and analyzed using grounded theory methodology until data saturation was reached (n = 20). Two core categories with subcategories emerged from the data: The Roots of Risk (Los raices del riesgo) and The Tangled Branches (Las Ramas Enredadas). The results of the study provided some important clinical implications as well as directions for future research with Hispanic MSM.

  10. Discusión de las aproximaciones utilizadas en el estudio de la recombinación dielectrónica de los metales en envolturas estelares

    NASA Astrophysics Data System (ADS)

    Cruzado, A.; di Rocco, H. O.; Ringuelet, A.

    Se calcularon nuevos parámetros atómicos del MgI reemplazando los niveles de energía teóricos por los observados. Con ellos se calculó nuevamente el flujo originado en la Recombinación Dielectrónica (RD) del MgII y se comparó con resultados anteriores. Se evaluó también la posible influencia de diferentes fuentes de opacidad, en el flujo originado en la RD de los metales en atmósferas extendidas de estrellas tempranas. En particular, se calculó la profundidad óptica de las líneas de MgI para diferentes condiciones físicas del medio.

  11. Estimates of hydraulic properties from a one-dimensional numerical model of vertical aquifer-system deformation, Lorenzi site, Las Vegas, Nevada

    USGS Publications Warehouse

    Pavelko, Michael T.

    2004-01-01

    Land subsidence related to aquifer-system compaction and ground-water withdrawals has been occurring in Las Vegas Valley, Nevada, since the 1930's, and by the late 1980's some areas in the valley had subsided more than 5 feet. Since the late 1980's, seasonal artificial-recharge programs have lessened the effects of summertime pumping on aquifer-system compaction, but the long-term trend of compaction continues in places. Since 1994, the U.S. Geological Survey has continuously monitored water-level changes in three piezometers and vertical aquifer-system deformation with a borehole extensometer at the Lorenzi site in Las Vegas, Nevada. A one-dimensional, numerical, ground-water flow model of the aquifer system below the Lorenzi site was developed for the period 1901-2000, to estimate aquitard vertical hydraulic conductivity, aquitard inelastic skeletal specific storage, and aquitard and aquifer elastic skeletal specific storage. Aquifer water-level data were used in the model as the aquifer-system stresses that controlled simulated vertical aquifer-system deformation. Nonlinear-regression methods were used to calibrate the model, utilizing estimated and measured aquifer-system deformation data to minimize a weighted least-squares objective function, and estimate optimal property values. Model results indicate that at the Lorenzi site, aquitard vertical hydraulic conductivity is 3 x 10-6 feet per day, aquitard inelastic skeletal specific storage is 4 x 10-5 per foot, aquitard elastic skeletal specific storage is 5 x 10-6 per foot, and aquifer elastic skeletal specific storage is 3 x 10-7 per foot. Regression statistics indicate that the model and data provided sufficient information to estimate the target properties, the model adequately simulated observed data, and the estimated property values are accurate and unique.

  12. Capacitación-acción participativa: una experiencia de 24 años en las comunidades rurales de Oaxaca, México.

    PubMed

    Ysunza, Alberto M; Diez-Urdanivia, Silvia; Pérez-Gil, Sara E

    2016-06-08

    Resumen:En este artículo presentamos el proyecto de capacitación llevado a cabo en comunidades de la sierra y costa de Oaxaca, México, desde 1991, por el Centro de Capacitación Integral para Promotores Comunitarios (CECIPROC). La decisión de hacer este trabajo en Oaxaca responde a que ese estado ocupa uno de los primeros lugares de marginación y de desnutrición en menores de 5 años. El objetivo es describir un modelo de capacitación y compartir parte de las experiencias derivadas, tanto del modelo como del trabajo realizado en las distintas áreas (nutrición y alimentación, salud comunitaria, ecología y etnobotánica, y educación y organización), por promotores mujeres y hombres en sus comunidades.La experiencia obtenida en 24 años muestra la factibilidad técnica y social del proyecto en el ámbito de la salud, el reconocimiento social del proyecto del CECIPROC como un organismo civil que ha aportado alternativas como solución a la problemática de salud, el hacer suyo el proyecto por algunos promotores y los diferentes obstáculos a los que se ha enfrentado. Enfatizamos el hecho de que la situación socioeconómica y política prevaleciente en el estado de Oaxaca es una limitante para el buen desarrollo de los programas colectivos de salud, e insistimos en la necesidad de compartir nuestras experiencias para que puedan ser utilizadas en la planificación y ejecución de otros proyectos.

  13. Similarities in the dolomitization of upper Miocene reef complexes in Mallorca and the Las Negras areas, Spain: Possible evidence for a Mediterranean dolomitizing event during the Messinian

    SciTech Connect

    Oswald, E.J.; Meyers, W.J. ); Franseen, E.K. )

    1991-03-01

    Reef complexes in the Las Negras area and the island of Mallorca, over 600 km to the northeast, contain dolomite with remarkably similar stratigraphic distribution and petrographic characteristics. In both reef complexes dolomite occurs as 5-50 {mu}m euhedral cements and microcrystalline replacement of red-algal fragments and muds. In addition, anhedral, moldic-zoned dolomite cements (5-20 {mu}m) are abundant in the youngest reefs of both areas. All inter-reefal erosional surfaces are cross-cut by dolomite cements. Distribution of dolomite within the reefal sequences is controlled by (1) proximity to the youngest reef margin. Dolomite abundances decrease from 100% to 0% over a 10 km transect into the platform interior in Mallorca. Stratigraphic and petrographic timing support a dolomitization event following exposure of the reefs, during initial deposition of the onlapping Messinian sequence in Mallorca, and before Pliocene deposition in Las Negras. In both areas, dolomitization took place as a Messinian transgression covered the reefs. Evidence for multiple dolomitization events has not been found. Mallorcan dolomites have heavy stable isotopes suggesting saline dolomitizing fluids. One hypothesis for dolomitization invokes brines associated with the deposition of extensive Messinian basinal evaporites. An early Messinian evaporitic lowstand could concentrate marine brines, and with the ensuing transgression bring them in contact with CaCo{sub 3} platforms, dolomitizing them. The similar styles and timing of dolomitization in these two distinct and distant reef settings suggest that dolomitization of late Miocene reefs around the western Mediterranean may have been genetically related to the Messinian salinity crisis.

  14. U.S. Geological Survey Subsidence Interest Group Conference; proceedings of the Technical Meeting, Las Vegas, Nevada, February 14-16, 1995

    USGS Publications Warehouse

    Prince, Keith R.; Leake, Stanley A.

    1997-01-01

    Introducation to Papers: This report is a compilation of short papers that are based on oral presentations summarizing the results of recent research that were given at the third meeting of the Subsidence Interest Group held in Las Vegas, Nevada, February 14?16, 1995. The report includes case studies of land subsidence and aquifer-system deformation resulting from fluid withdrawal, geothermal development, and mine collapse. Methods for monitoring land subsidence using Global Positioning System technology for the rapid and accurate measurement of changes in land-surface altitude also are described. The current status of numerical simulation of land subsidence in the USGS is summarized, and several of the short papers deal with the development and application of new numerical techniques for simulation and quantification of aquifersystem deformation. Not all oral presentations made at the meeting are documented in this report. Several of the presentations were of ongoing research and as such, the findings were provisional in nature and were offered at the meeting to stimulate scientific discussion and debate among colleagues. The information presented in this report, although only a subset of the proceedings of the meeting in Las Vegas, should help expand the scientific basis for management decisions to mitigate or control the effects of land subsidence. The short papers describing the results of these studies provide a cross section of ongoing research in aquifer mechanics and land subsidence and also form an assessment of the current technology and 'state of the science.' The analytical and interpretive methods described in this report will be useful to scientists involved in studies of ground-water hydraulics and aquifer-system deformation.

  15. The Gruta de las Maravillas (Aracena, South-West Iberia): Setting and origin of a cave in marbles from dissolution of pyrite

    NASA Astrophysics Data System (ADS)

    Martínez-Moreno, F. J.; Pedrera, A.; Galindo-Zaldívar, J.; López-Chicano, M.; Azor, A.; Martín-Rosales, W.; Ruano, P.; Calaforra, J. M.; Hódar-Pérez, A.

    2016-01-01

    The Gruta de las Maravillas cave is located at the WNW side of the Cerro del Castillo hill in Aracena (Huelva, SW Spain). The cavity is hosted within marbles included in a strip of high-grade metamorphic rocks belonging to the so-called Aracena Massif in the southernmost Ossa-Morena Zone. The hill is made up of granodiorites, marbles, quartzites, and gneisses, with the foliation trending N110°E and dipping roughly 60-80° towards NE. The marbles appear highly deformed in ductile conditions, with isoclinal folds of different sizes, boudins, porphyroblasts with sigmoidal morphology, and left-lateral S-C shear fabrics. Close to the granodiorite contact, the marbles include a thin band of disseminated and massive pyrite, partially transformed to Fe-oxides. Analysis of the brittle deformation and the associated paleostresses indicates a NE-SW oriented maximum compression, probably related to the latest Variscan collisional tectonics (300 Ma; Late Carboniferous). The Gruta de las Maravillas is divided into three main levels (located at 650, 665 and 685 m a.s.l.), the dissolution having progressed from top to bottom in different stages of stability of the water table. The initial dissolution phases were probably favoured by the presence of pyrite in the host rock, which, in turn, would have caused acidification of the circulating water. Favouring this hypothesis, a thin layer of Fe-oxides, locally including gypsum, covers some parts of the cave walls. The morphology and structure of the cavity result from interaction between the general NNE dipping foliation with sub-perpendicular joints, the pyrite-bearing band in the host marbles, and the descending water table.

  16. Proving the Orbits of the Galilean Moons Through Astrophotography. (Spanish Title: Comprobando Las Órbitas de Las Lunas Galileanas a Través de la Astrofotografía.) Evidenciando as Órbitas das Luas Galileanas Atravéd da Astrofotografia

    NASA Astrophysics Data System (ADS)

    Iachel, Gustavo

    2009-12-01

    An activity related to the observation of the Galilean moons and to amateur astrophotography is presented in this work. Through the reading of excerpts of the book Sidereus Nuncius (Sidereal Messenger), by Galileo, it is possible to trace a methodology to observe the planet and its natural satellites and, with the aid of the astrophotography, to analyze the field recordings. Moreover, it is possible to compare the images obtained after plotting the relative positions of these moons to prove their orbits. This activity can be conducted by teachers, students and amateur astronomers, in order to develop their capabilities of observation of astronomical phenomena. Se presenta en este trabajo una actividad relacionada a la observación de las lunas Galileanas y a la astrofotografía amateur. A través de la lectura de tramos de la obra Sidereus Nuncius (El Mensajero Sideral) de Galileo, es posible trazar una metodología para la observación del planeta y de sus satélites naturales y, con el auxilio de la astrofotografía, analizar las anotaciones de campo. Además, es posible comparar las imágenes obtenidas con el gráfico de las posiciones relativas de estas lunas para comprobar sus órbitas. Esa actividad puede ser realizada por maestros, estudiantes y astrónomos amateurs, de forma a desarrollar sus capacidades de observación de los fenómenos astronómicos. Uma atividade relacionada à observação das luas Galileanas e à astrofotografia amadora é apresentada neste trabalho. Através da leitura de trechos da obra Sidereus Nuncius (Mensageiro Sideral), de Galileu, é possível traçar uma metodologia para a observação do planeta e de seus satélites naturais e, com o auxílio da astrofotografia, analisar as anotações de campo. Além disso, é possível comparar as imagens obtidas com o gráfico das posições relativas destas luas para evidenciar suas órbitas. Essa atividade pode ser realizada por professores, estudantes e astrônomos amadores, de forma a

  17. Theoretical and structural analysis of the active site of the transcriptional regulators LasR and TraR, using molecular docking methodology for identifying potential analogues of acyl homoserine lactones (AHLs) with anti-quorum sensing activity.

    PubMed

    Ahumedo, Maicol; Díaz, Antonio; Vivas-Reyes, Ricardo

    2010-02-01

    In the present study the homology of transcriptional receptors LuxR type were evaluated using as point of reference the receptors TraR and LasR of the bacterial types Agrobacterium tumefaciens and Pseudomonas aureginosa respectively. A series of alignments were performed in order to demonstrate that the active site of the protein is conserved in wide range of gram negative bacteria. Moreover, some docking calculations were carried out for analogs of the acyl homoserin lactones (AHLs) and regulatory proteins LasR and TraR, to understand the complex microenvironment in which the ligands are exposed. The molecular alignments show clearly that there are preserved motifs in the residues (Y53, Y61, W57, D70, W85 to TraR, Y56, Y64, W60, D73, W88 to LasR) analyzed, which may serve as site-specific targets for the development of potential antagonists. In this study was found that the anti-quorum sensing activity of the AHLs molecular analogs appears to depend on; the structure of the lactone ring and on appropriate combination of absolute and relative stereochemistry of the carbonyl (C=O) and amide (NH(2)) groups of the side chain of these AHLs molecular analogs, in combination with the interactions with the conserved amino acids (D73, W60, Y56, S129 to LasR and D70, W57, Y53 to TraR) of the LuxR type protein family.

  18. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on e-Learning (Las Palmas de Gran Canaria, Spain, July 21-24, 2015)

    ERIC Educational Resources Information Center

    Nunes, Miguel Baptista, Ed.; McPherson, Maggie, Ed.

    2015-01-01

    These proceedings contain the papers of the International Conference e-Learning 2015, which was organised by the International Association for Development of the Information and Society and is part of the Multi Conference on Computer Science and Information Systems (Las Palmas de Gran Canaria, Spain, July 21-24, 2015). The e-Learning 2015…

  19. Informe de la EPA muestra que las emisiones de sustancias químicas tóxicas al aire provenientes de instalaciones industriales se redujeron más de la mitad desde el 2005

    EPA Pesticide Factsheets

    Comunicado de prensa de la EPA: Informe de la EPA muestra que las emisiones de sustancias químicas tóxicas al aire provenientes de instalaciones industriales se redujeron más de la mitad desde el 2005

  20. EPA se mueve hacia la prohibición de desengrasantes en aerosol y quitamanchas para lavado en seco como una de las primeras acciones reglamentarias conforme a la ley reformada de sustancias químicas

    EPA Pesticide Factsheets

    Comunicado de prensa de EPA: EPA se mueve hacia la prohibición de desengrasantes en aerosol y quitamanchas para lavado en seco como una de las primeras acciones reglamentarias conforme a la ley reformada de sustancias químicas

  1. Slope-apron deposition in an ordovician arc-related setting: The Vuelta de Las Tolas Member (Suri Formation), Famatina Basin, northwest Argentina

    USGS Publications Warehouse

    Mangano, M.G.; Buatois, L.A.

    1997-01-01

    The Ordovician Suri Formation is part of the infill of the Famatina Basin of northwest Argentina, which formed in an active setting along the western margin of early Paleozoic Gondwana. The lower part of this formation, the Vuelta de Las Tolas Member, records sedimentation on a slope apron formed in an intra-arc basin situated on a flooded continental arc platform. The coincidence of a thick Arenig-Llanvirn sedimentary succession and volcanic-plutonic arc rocks suggests an extensional or transtensional arc setting, and is consistent with evidence of an extensional regime within the volcanic arc in the northern Puna region. The studied stratigraphic sections consist of volcanic rocks and six sedimentary facies. The facies can be clustered into four facies associations. Association 1, composed of facies A (laminated siltstones and mudstones) and B (massive mudstones and siltstones), is interpreted to have accumulated from silty-muddy high-and low-density turbidity currents and highly fluid, silty debris flows, with subsequent reworking by bottom currents, and to a lesser extent, hemipelagic suspension in an open-slope setting. Facies association 2 is dominated by facies C (current-rippled siltstones) strata. These deposits are interpreted to record overbank sedimentation from fine-grained turbidity currents. Facies E (matrix-supported volcanic breccias) interbedded with andesitic lava units comprises facies association 3. Deposition was contemporaneous with subaqueous volcanic activity, and accumulated from cohesive debris flows in a coarse-grained wedge at the base of slope. Facies association 4 is typified by facies D (vitric fine-grained sandstones and siltstones) and F (channelized and graded volcanic conglomerates and breccias) deposits. These strata commonly display thinning-and fining-upward trends, indicating sedimentation from highly-concentrated volcaniclastic turbidity currents in a channelized system. The general characteristics of these deposits of fresh

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

    NASA Astrophysics Data System (ADS)

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

    2006-11-01

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

  3. Ground-water conditions in Las Vegas Valley, Clark County, Nevada; Part II, Hydrogeology and simulation of ground-water flow

    USGS Publications Warehouse

    Morgan, D.S.; Dettinger, M.D.

    1994-01-01

    Groundwater withdrawals in Las Vegas Valley, Nevada, primarily for municipal supplies, totaled more than 2.5 million acre-ft between 1912 and 1981, with a peak annual withdrawal rate of 88,000 acre-ft in 1968. Effects of heavy pumping are evident over large areas of the valley but are more pronounced near the major well fields. Secondary recharge from lawn irrigation and other sources is estimated to have totaled more than 340,000 acre-ft during 1972-81. Resulting rises in water-level in shallow, unconfined aquifers in the central and southeastern parts of the valley have caused: widespread water-logging of soils; increased groundwater discharge to Las Vegas Wash and its tributaries; and potential for degradation of water quality in deeper aquifers by accentuating downward vertical hydraulic potential in areas where shallow groundwater has high concentrations of dissolved solids and nitrate. A 3-dimensional groundwater flow model of the valley-fill aquifer system was constructed for use in evaluating possible groundwater management alternatives aimed at alleviating problems related to overdraft and water-logging while maximizing use of the groundwater resources. Natural recharge to the valley-fill aquifers is about 33,000 acre-ft/yr; in 1979, an estimated 44,000 acre-ft of secondary recharge infiltrated to the near-surface and developed-zone aquifers. Peak water use for lawn irrigation during summer results in rates of secondary recharge that may increase threefold from winter rates. Simulated rates of seepage to washes in the valley increased correspondingly from an average of 850 acre-ft/mo in winter to about 1,300 acre-ft/mo in the summer. Groundwater withdrawals by pumping totaled 620,000 acre-ft during 1972-81, and model results indicate that about 190,000 acre-ft of that total was derived from storage. Use of the model as a predictive tool was demonstrated by simulating the effects of using most municipal wells only during the peak-demand season of June 1

  4. Petrography and geochemistry of achnelithic tephra from Las Herrerías Volcano (Calatrava volcanic field, Spain): Formation of nephelinitic achneliths and post-depositional glass alteration

    NASA Astrophysics Data System (ADS)

    Carracedo-Sánchez, M.; Sarrionandia, F.; Arostegui, J.; Errandonea-Martin, J.; Gil-Ibarguchi, J. I.

    2016-11-01

    We present the results of a petrographic and geochemical study carried out on a layer of achnelithic tephra outcropping at the base of the volcanic cone of Las Herrerías (Miocene-Quaternary volcanic region of Campo de Calatrava, Spain). The tephra, with a composition of nephelinite and ash (< 1 mm) to coarse lapilli (ca. 1 cm) in size, is made of intact isolated achneliths (mostly elongated and spheroidal, including Pele's tears), achnelith fragments and rare welded achneliths. The achneliths at Las Herrerías were generated in a gas-rich fire fountain that fragmented the magma into micro- to nanometre particles. The low viscosity of the nephelinitic blebs (< 1235 Pa.s) inside the hottest (ca. 900 °C), inner zone of the fountain allowed the development of the characteristic fluidal shapes of these pyroclasts and their welding above the glass transition temperature (533-669 °C). The sideromelane glass of the achneliths, also nephelinitic in composition, is variably altered to palagonite. The palagonitization was isovolumetric and took place in a near closed system at the achnelith scale. Palagonitization involved depletion in the concentration (g/cm3) of all major elements and notable increase in H2O content. The elements liberated by this process formed smectite with an average structural formula comprised between those of beidellite and nontronite end terms: (Na0.01K0.03Ca0.18) (Mg0.22Fe0.16)2 + (Fe0.48Al1.02)3 + (Ti0.18)4 + (Si3.58Al0.42) O10(OH)2. The degree of palagonitization in each achnelith was likely related to the amount of water incorporated by individual clasts at the moment of their deposition in a volcanic maar lake. Afterwards, there was no more water circulation through the achnelithic tephra, which was sealed from water by overlying hydrovolcanic tuff deposits. It was this isolation that made possible the preservation of glass to the present day.

  5. Physical Measurements of Water Properties Across the Mouth of the Gulf of California during April 2013 (PESCAR24 Cruise) (Mediciones Fisicas de las Propiedades del Agua a Traves de la Boca del Golfo de California Durante Abril de 2013 (Crucero PESCAR24)

    DTIC Science & Technology

    2013-11-26

    interés en determinar la estructura de la Corriente de California en el área (Rago et al., 1992). Un aspecto relevante del proyecto fue la medición...salinómetros y las mediciones de conductividad por el CTD en el momento que las botellas Niskin fueron disparadas. En este punto, sin embargo, fue

  6. Risk of exposure to second hand smoke for adolescents in Las Vegas casinos: an evaluation of the Nevada Clean Indoor Air Act.

    PubMed

    Cochran, Christopher; Henriques, Dominic; York, Nancy; Lee, Kiyoung

    2012-01-01

    Since the Surgeon General's groundbreaking report of 1964, "Smoking and Health," the medical and scientific communities have uncovered the devastating effects of tobacco smoke on health. In reaction to these findings, local and state governments have enacted a variety of clean air acts to prevent unnecessary exposure to this known carcinogen. The Nevada Clean Indoor Air Act (NCIAA), a non-comprehensive smoke-free law, permits smoking in designated areas of casinos, bars, and taverns. With many Las Vegas casinos catering to all ages, this study was designed to evaluate the efficacy of NCIAA in protecting children from second hand smoke exposure. Using a device that measures ambient air particle matter concentrations, this study sampled the air quality in 15 casino gaming areas and corresponding non-smoking, children-friendly areas. The results indicate that current policy fails to preserve indoor air quality in these children-friendly areas. Furthermore, this research suggests the adoption of a more comprehensive, 100% smoke-free policy as the only effective remedy.

  7. Geophysical characterization of stratigraphical surfaces: Basin floor and sedimentological architectural elements of Las Tablas de Daimiel (Quaternary of southern-central Spain)

    NASA Astrophysics Data System (ADS)

    Rey, Javier; Martínez, Julián; Mediavilla, Rosa; Santisteban, Juan I.; Castaño, Silvino; de la Losa, Almudena

    2017-01-01

    In this paper we analyse and compare the efficiency of electrical resistivity imaging (ERI) and ground-penetrating radar (GPR) as tools for stratigraphic and sedimentological studies. To this end, we carried out borehole drilling and geophysical survey campaigns in two locations in Las Tablas de Daimiel area (Ciudad Real, Spain). In this region, the Quaternary record is build up by siliciclastic deposits (gravel, sand and silt) of fluvial origin and organic matter-rich sediments (peat, clay and silty clay rich in organic matter) and carbonates (biogenic deposits mainly made up of Characeae) deposited in fluvial wetland environments that rest on Ordovician quartzites and Pliocene karstified carbonates. Electrical resistivity imaging (ERI) supported by surface and subsurface (boreholes) lithological information allow to identify the geometry of the basement-Quaternary boundary in two areas. The morphology of this boundary is controlled by fractures and the karstification of the top of the Pliocene limestones. Thirteen GPR profiles (100 and 250 MHz antenna) provide information about the morphology and internal structure of the sedimentary units, down to 4 m below the surface. The observed features include: onlap of the sediments on the edge of the basin, fossilization of small paleo-reliefs by lacustrine deposits and channel fills in the Holocene deposits, and the sinking-collapse structures in the Neogene substratum.

  8. Fast emplacement of extensive pahoehoe flow-fields: the case of the 1736 flows from Montaña de las Nueces, Lanzarote

    NASA Astrophysics Data System (ADS)

    Solana, M. C.; Kilburn, C. R. J.; Rodriguez Badiola, E.; Aparicio, A.

    2004-04-01

    The 1730-36 Timanfaya eruption on Lanzarote, in the Canary Islands, is the second largest historical effusion on record. During its final stages, in 1736, the eruption produced the Montaña de las Nueces flow-field, consisting of sheets of pahoehoe lava that, within 4 weeks, had covered 32 km 2 and reached a maximum length of almost 21 km. The tholeiitic lavas have pahoehoe surface features, but internal structures that are normally associated with massive aa flows, suggesting that their fronts advanced as single units rather than as a collection of budding pahoehoe tongues. Volume conservation and a simple model of crustal failure suggest that the main flows advanced at about 0.02 ms -1 over the prevailing slopes of ˜1°. The rates of advance are (1) consistent with emplacement near the transition from pahoehoe to aa, and (2) about an order of magnitude greater than would have been expected by analogy with Hawaiian pahoehoe flow-fields of similar dimensions. Surface texture and morphology, therefore, is an insufficient guide for constraining the rate and style of pahoehoe emplacement, and a flow's internal structure must be established before its characteristics are used to infer eruption conditions and potential hazard.

  9. Multivariate analysis, mass balance techniques, and statistical tests as tools in igneous petrology: application to the Sierra de las Cruces volcanic range (Mexican Volcanic Belt).

    PubMed

    Velasco-Tapia, Fernando

    2014-01-01

    Magmatic processes have usually been identified and evaluated using qualitative or semiquantitative geochemical or isotopic tools based on a restricted number of variables. However, a more complete and quantitative view could be reached applying multivariate analysis, mass balance techniques, and statistical tests. As an example, in this work a statistical and quantitative scheme is applied to analyze the geochemical features for the Sierra de las Cruces (SC) volcanic range (Mexican Volcanic Belt). In this locality, the volcanic activity (3.7 to 0.5 Ma) was dominantly dacitic, but the presence of spheroidal andesitic enclaves and/or diverse disequilibrium features in majority of lavas confirms the operation of magma mixing/mingling. New discriminant-function-based multidimensional diagrams were used to discriminate tectonic setting. Statistical tests of discordancy and significance were applied to evaluate the influence of the subducting Cocos plate, which seems to be rather negligible for the SC magmas in relation to several major and trace elements. A cluster analysis following Ward's linkage rule was carried out to classify the SC volcanic rocks geochemical groups. Finally, two mass-balance schemes were applied for the quantitative evaluation of the proportion of the end-member components (dacitic and andesitic magmas) in the comingled lavas (binary mixtures).

  10. Regional and residual anomaly separation in microgravity maps for cave detection: The case study of Gruta de las Maravillas (SW Spain)

    NASA Astrophysics Data System (ADS)

    Martínez-Moreno, F. J.; Galindo-Zaldívar, J.; Pedrera, A.; Teixidó, T.; Peña, J. A.; González-Castillo, L.

    2015-03-01

    Gravity can be considered an optimal geophysical method for cave detection, given the high density contrast between an empty cavity and the surrounding materials. A number of methods can be used for regional and residual gravity anomaly separation, although they have not been tested in natural scenarios. With the purpose of comparing the different methods, we calculate the residual anomalies associated with the karst system of Gruta de las Maravillas whose cave morphology and dimensions are well-known. A total of 1857 field measurements, mostly distributed in a regular grid of 10 × 10 m, cover the studied area. The microgravity data were acquired using a Scintrex CG5 gravimeter and topography control was carried out with a differential GPS. Regional anomaly maps were calculated by means of several algorithms to generate the corresponding residual gravimetric maps: polynomial first-order fitting, fast Fourier transformation with an upward continuation filter, moving average, minimum curvature and kriging methods. Results are analysed and discussed in terms of resolution, implying the capacity to detect shallow voids. We propose that polynomial fitting is the best technique when microgravity data are used to obtain the residual anomaly maps for cave detection.

  11. Model of hydrological behaviour of the anthropized semiarid wetland of Las Tablas de Daimiel National Park (Spain) based on surface water-groundwater interactions

    NASA Astrophysics Data System (ADS)

    Aguilera, H.; Castaño, S.; Moreno, L.; Jiménez-Hernández, M. E.; de la Losa, A.

    2013-05-01

    Las Tablas de Daimiel National Park (TDNP) in Spain is one of the most important semiarid wetlands of the Mediterranean area. The inversion of the regional groundwater flow, primarily due to overexploitation and inadequate aquifer management, has led to degradation. The system has turned from a groundwater discharge zone into a recharge zone, and has remained mostly dry since the 1980s. High heterogeneity and complexity, enhanced by anthropogenic management action, hampers prediction of the surface-groundwater system response to flooding events. This study analyses these interactions and provides empirical evidence to define a conceptual model of flooding-infiltration-groundwater dynamics through the application of a few simple analysis tools to basic hydrological data. Relevant surface water-groundwater interactions are mainly localized in the left (west) margin of TDNP, as confirmed by the fast responses to flooding observed in the hydrochemic, hydrodynamic and isotopic data. During drying periods, small artificial and/or low-flow natural floods are followed by infiltration of evaporated poor-quality ponding water into saline low-permeability layers. The results allow an improved understanding of the hydrological behaviour essential to support efficient management practices. The relative simplicity of the methodology allows for its application in other similar complex groundwater-linked wetlands where detailed knowledge of local geology is still absent.

  12. Multivariate Analysis, Mass Balance Techniques, and Statistical Tests as Tools in Igneous Petrology: Application to the Sierra de las Cruces Volcanic Range (Mexican Volcanic Belt)

    PubMed Central

    Velasco-Tapia, Fernando

    2014-01-01

    Magmatic processes have usually been identified and evaluated using qualitative or semiquantitative geochemical or isotopic tools based on a restricted number of variables. However, a more complete and quantitative view could be reached applying multivariate analysis, mass balance techniques, and statistical tests. As an example, in this work a statistical and quantitative scheme is applied to analyze the geochemical features for the Sierra de las Cruces (SC) volcanic range (Mexican Volcanic Belt). In this locality, the volcanic activity (3.7 to 0.5 Ma) was dominantly dacitic, but the presence of spheroidal andesitic enclaves and/or diverse disequilibrium features in majority of lavas confirms the operation of magma mixing/mingling. New discriminant-function-based multidimensional diagrams were used to discriminate tectonic setting. Statistical tests of discordancy and significance were applied to evaluate the influence of the subducting Cocos plate, which seems to be rather negligible for the SC magmas in relation to several major and trace elements. A cluster analysis following Ward's linkage rule was carried out to classify the SC volcanic rocks geochemical groups. Finally, two mass-balance schemes were applied for the quantitative evaluation of the proportion of the end-member components (dacitic and andesitic magmas) in the comingled lavas (binary mixtures). PMID:24737994

  13. N-Acetylglucosamine Inhibits LuxR, LasR and CviR Based Quorum Sensing Regulated Gene Expression Levels

    PubMed Central

    Kimyon, Önder; Ulutürk, Zehra İ.; Nizalapur, Shashidhar; Lee, Matthew; Kutty, Samuel K.; Beckmann, Sabrina; Kumar, Naresh; Manefield, Mike

    2016-01-01

    N-acetyl glucosamine, the monomer of chitin, is an abundant source of carbon and nitrogen in nature as it is the main component and breakdown product of many structural polymers. Some bacteria use N-acyl-L-homoserine lactone (AHL) mediated quorum sensing (QS) to regulate chitinase production in order to catalyze the cleavage of chitin polymers into water soluble N-acetyl-D-glucosamine (NAG) monomers. In this study, the impact of NAG on QS activities of LuxR, LasR, and CviR regulated gene expression was investigated by examining the effect of NAG on QS regulated green fluorescent protein (GFP), violacein and extracellular chitinase expression. It was discovered that NAG inhibits AHL dependent gene transcription in AHL reporter strains within the range of 50–80% reduction at low millimolar concentrations (0.25–5 mM). Evidence is presented supporting a role for both competitive inhibition at the AHL binding site of LuxR type transcriptional regulators and catabolite repression. Further, this study shows that NAG down-regulates CviR induced violacein production while simultaneously up-regulating CviR dependent extracellular enzymes, suggesting that an unknown NAG dependent regulatory component influences phenotype expression. The quorum sensing inhibiting activity of NAG also adds to the list of compounds with known quorum sensing inhibiting activities. PMID:27602027

  14. Study the Cyclic Plasticity Behavior of 508 LAS under Constant, Variable and Grid-Load-Following Loading Cycles for Fatigue Evaluation of PWR Components

    SciTech Connect

    Mohanty, Subhasish; Barua, Bipul; Soppet, William K.; Majumdar, Saurin; Natesan, Ken

    2016-09-01

    This report provides an update of an earlier assessment of environmentally assisted fatigue for components in light water reactors. This report is a deliverable in September 2016 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2016 report, we presented a detailed thermal-mechanical stress analysis model for simulating the stress-strain state of a reactor pressure vessel and its nozzles under grid-load-following conditions. In this report, we provide stress-controlled fatigue test data for 508 LAS base metal alloy under different loading amplitudes (constant, variable, and random grid-load-following) and environmental conditions (in air or pressurized water reactor coolant water at 300°C). Also presented is a cyclic plasticity-based analytical model that can simultaneously capture the amplitude and time dependency of the component behavior under fatigue loading. Results related to both amplitude-dependent and amplitude-independent parameters are presented. The validation results for the analytical/mechanistic model are discussed. This report provides guidance for estimating time-dependent, amplitude-independent parameters related to material behavior under different service conditions. The developed mechanistic models and the reported material parameters can be used to conduct more accurate fatigue and ratcheting evaluation of reactor components.

  15. The Guyanas = Las Guayanas. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor

    Written for teachers to use with migrant children in elementary grades and to highlight the many Americas, this bilingual English/Spanish social studies resource booklet provides historical and cultural background information on the Guyanas--French Guyana, Surinam, and Guyana. A table of contents indicates the language--Spanish or English--in…

  16. Eficacia de la detección sistemática de la gripe en las fronteras en los viajeros que llegan por vía aérea*

    PubMed Central

    Priest, Patricia C.; Jennings, Lance C.; Duncan, Alasdair R.; Brunton, Cheryl R.; Baker, Michael G.

    2015-01-01

    Objetivos. Se midieron los síntomas y la prevalencia de la gripe (también llamada influenza), así como la eficacia del mecanismo de detección sistemática basado en los síntomas y la temperatura para diagnosticar la gripe en viajeros internacionales que llegaban por vía aérea. Métodos. El presente estudio transversal recopiló datos de viajeros que llegaron al aeropuerto internacional de Christchurch (Nueva Zelandia) en el invierno del 2008 mediante un cuestionario de salud, medición de la temperatura y toma de muestras de las vías respiratorias. Resultados. De los viajeros, 15 976 (68%) entregaron los formularios completos. De ellos, 17% notificaron al menos un síntoma de gripe; los síntomas más comunes fueron rinorrea o congestión nasal (10%) y tos (8%). Se tomaron muestras de las vías respiratorias de 3 769 viajeros. La prevalencia estimada de la gripe fue de 1,1% (4% en las personas sintomáticas, 0,2% en las asintomáticas). La sensibilidad de los criterios de detección varió de 84% para “cualquier síntoma” a 3% para la fiebre de 37,8 °C o mayor. El valor predictivo positivo fue bajo para todos los criterios. Conclusiones. El método de detección sistemática en las fronteras mediante la autonotificación de síntomas y la toma de la temperatura presenta limitaciones para impedir que una gripe pandémica entre en un país. Basarse en criterios como “cualquier síntoma” o la tos haría que se investigara a varias personas no infectadas, mientras que algunas personas infectadas pasarían inadvertidas. Si se usaran criterios más específicos como la fiebre, la mayoría de las personas infectadas entrarían en el país a pesar del mecanismo de detección.

  17. Bolivia. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; Avery, Robert S.

    Written for teachers to use with migrant children in elementary grades and to highlight the many Americas, this bilingual English/Spanish social studies resource booklet provides historical and cultural information on Bolivia. A table of contents indicates the language--Spanish or English--in which the topics are written. The quarterly provides an…

  18. Colombia. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; Doran, Sandra

    Written for teachers to use with migrant children in elementary grades to highlight the many Americas, this bilingual English/Spanish social studies resource booklet provides historical and cultural background information on Colombia and features biographies of Colombian leaders and artists. A table of contents indicates the language--Spanish or…

  19. Las Maestras: Pioneers in Education.

    ERIC Educational Resources Information Center

    Gonzales-Berry, Erlinda

    1997-01-01

    Highlights from interviews with three Hispanic women who taught rural children in New Mexico over 60 years ago notes the recurring motifs of poverty, supportive families, obstructive political structures, social discrimination, and community vitality and support. Investigates how these women were able to cross the boundary that separated…

  20. Venezuela. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; Avery, Robert S.

    This bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Venezuela's history, geography, economy, and culture for teachers to use with migrant children in the elementary grades. Topics presented in the English portion include climate, land, people, customs, government, arts, food, culture, wildlife,…

  1. Peru. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; Doran, Sandra

    Intended for elementary teachers to use with migrant students, this bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Peru's history, geography, economy, and culture. Topics included are the people, geographic regions, festivals and celebrations, the economy, natural resources, Lake Titicaca,…

  2. SRTM Anaglyph: Las Bayas, Argentina

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The interplay of volcanism, stream erosion and landslides is evident in this Shuttle Radar Topography Mission view of the eastern flank of the Andes Mountains, southeast of San Carlos de Bariloche, Argentina. Older lava flows emanating from the Andes once covered much of this area. Younger, local volcanoes (seen here as small peaks) then covered parts of the area with fresh, erosion resistant flows (seen here as very smooth surfaces). Subsequent erosion has created fine patterns on the older surfaces (bottom of the image) and bolder, irregular patterns through and around the younger surfaces (upper center and right center). Meanwhile, where a large stream immediately borders the resistant plateau (center of the image), lateral erosion has undercut the resistant plateau causing slivers of it to fall into the stream channel. This scene well illustrate show topographic data alone can reveal some aspects of recent geologic history.

    This anaglyph was produced by first shading a preliminary elevation model from data acquired by the Shuttle Radar Topography Mission. The stereoscopic effect was then created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

    Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

    Size: 54.3 x 36.4 kilometers ( 33.7 x 22.6 miles) Location: 41.4 deg. South lat., 70.8 deg. West lon. Orientation: North toward the top Image Data: Shaded SRTM elevation model Date Acquired: February 2000

  3. LAS bioconcentration is isomer specific

    SciTech Connect

    Tolls, J.; Haller, M.; Graaf, I. de; Thijssen, M.H.C.; Sijm, D.T.H.M.

    1995-12-31

    The authors measured parent compound specific bioconcentration data for linear alkylbenzene sulfonates in Pimephales promelas. They did so by using cold, custom synthesized sulfophenyl alkanes. They observed that, within homologous series of isomers, the uptake rate constants (k{sub 1}) and the bioconcentration factor (BCF) increase with increasing number of carbon atoms in the alkyl chain (n{sub C-atoms}). In contrast, the elimination rate constant k{sub 2} appears to be independent of the alkyl chain length. Regressions of log BCF vs n{sub C-atoms} yielded different slopes for the homologous groups of the 5- and the 2-sulfophenyl alkane isomers. Regression of all log BCF-data vs log 1/CMC yielded a good description of the data. However, when regressing the data for both homologous series separately again very different slopes are obtained. The results therefore indicate that hydrophobicity-bioconcentration relationships may be different for different homologous groups of sulfophenyl alkanes.

  4. Ecuador. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; Doran, Sandra

    Designed for elementary teachers to use with migrant students, this bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Ecuador's history, geography, economy, and culture. Topics include the history of Ecuador's flag and coat of arms, geographic regions, food, Quito (the capital), recent wildlife…

  5. A comparison of greenhouse gas emissions and local area pollution of highspeed rail and air travel between Los Angeles and Las Vegas

    NASA Astrophysics Data System (ADS)

    Mullins, Damien

    Global warming is one of the most discussed global environmental issues in the world today. Global warming is driven by fossil fuel combustion emissions known as Green-house Gases (GHG). One of the major contributors to GHG emissions is the transport sector, emitting approximately 30% of total U.S. CO 2 emissions in 2010. Air travel contributed approximately 3.5% of total U.S. CO2 in 2008. High-speed Rail (HSR) is often touted as cleaner, more sustainable mode of transport than air travel. HSR is one of few modes of transport capable of competing with air travel for short to medium-haul distances. There has been considerable study of GHG emissions of each independently. Research has also been carried out into the economics and competition of these transport modes. However, there has been very limited study of the comparative emissions of each, apart from one study in Europe (Givoni, 2007). The current study was undertaken with the goal of quantifying potential emission savings due to mode substitution from air travel to HSR in the Los Angeles to Las Vegas corridor. This study only considered the emissions which occurred from the combustion of the relevant fuels, either in power plants or the engines of an aircraft. Emissions from fuel production/refining or transport of fuels were not considered. Another issue compared was Local Area Pollution (LAP), which is a measure of the severity of emissions effect on the environment. This was examined because all emissions from HSR occur close to the surface of the earth, and hence effect the local environment, while only a portion of aircraft emissions do. This study was carried out using internationally recognized emission inventory methodologies. For the air travel emission estimate methodologies and data published by the Intergovernmental Panel on Climate Change (IPCC) and the International Civil Aviation Organization (ICAO) were used. The HSR energy use was estimated from energy use data from currently running HSR

  6. Are single entry communities and cul-de-sacs a barrier to active transport to school in 11 elementary schools in Las Vegas, NV metropolitan area?

    PubMed

    Coughenour, Courtney; Clark, Sheila; Singh, Ashok; Huebner, Joshua

    2017-06-01

    Single entry communities (SECs) and cul-de-sacs minimize route choices and increase trip distance. Las Vegas' built environment facilitates the examination of these variables and active transport to school (ATS) rates. The purpose of this study was to examine the influence of SECs and cul-de-sacs on ATS rates in Las Vegas, NV elementary children. Parental-reported data was collected from 11 elementary schools on ATS rates (n = 1217). SECs and cul-de-sacs were quantified for each school zone. Logistic regression models were used to predict ATS. 23.9% of students reported ATS all of the time and 31.4% some of the time. SECs per school zone ranged from 0 to 25 (mean = 11.9). Cul-de-sacs ranged from 12 to 315 (mean = 138.3). Some ATS use was predicted by distance from school (p ≤ 0.001;OR = 0.61), parental education (high school: p = 0.004;OR = 0.53, some college: p = 0.001;OR = 0.50, 4 year degree: p = 0.004;OR = 0.52) and cul-de-sacs (p ≤ 0.001;OR = 0.99). A separate model using distance from school (p ≤ 0.001;OR = 0.61), parental education (high school: p = 0.002;OR = 0.51, some college: p ≤ 0.001;OR = 0.45, 4 year degree: p ≤ 0.001;OR = 0.45) and SECs (p ≤ 0.001;OR = 0.96) predicted some ATS. All ATS use was predicted by distance from school (p ≤ 0.001;OR = 0.58), parental education (Grades 9-11: p = 0.05;OR = 0.61, high school: p ≤ 0.001;OR = 0.45, some college: p ≤ 0.001;OR = 0.41, 4 year degree: p ≤ 0.001;OR = 0.38) and SECs (p ≤ 0.001;OR = 0.97). A separate model using distance from school (p ≤ 0.001;OR = 0.58), parental education (Grades 9-11: p = 0.041;OR = 0.59, high school: p ≤ 0.001;OR = 0.47, some college: p ≤ 0.001;OR = 0.44, 4 year degree: p ≤ 0.001;OR = 0.43) and cul-de-sacs (p ≤ 0.001;OR = 0.99) predicted all ATS. Current findings reveal that both SECs and cul-de-sacs were predictors of ATS beyond distance. Students with

  7. Lessons Learned From Large-Scale Evapotranspiration and Root Zone Soil Moisture Mapping Using Ground Measurements (meteorological, LAS, EC) and Remote Sensing (METRIC)

    NASA Astrophysics Data System (ADS)

    Hendrickx, J. M. H.; Allen, R. G.; Myint, S. W.; Ogden, F. L.

    2015-12-01

    Large scale mapping of evapotranspiration and root zone soil moisture is only possible when satellite images are used. The spatial resolution of this imagery typically depends on its temporal resolution or the satellite overpass time. For example, the Landsat satellite acquires images at 30 m resolution every 16 days while the MODIS satellite acquires images at 250 m resolution every day. In this study we deal with optical/thermal imagery that is impacted by cloudiness contrary to radar imagery that penetrates through clouds. Due to cloudiness, the temporal resolution of Landsat drops from 16 days to about one clear sky Landsat image per month in the southwestern USA and about one every ten years in the humid tropics of Panama. Only by launching additional satellites can the temporal resolution be improved. Since this is too costly, an alternative is found by using ground measurements with high temporal resolution (from minutes to days) but poor spatial resolution. The challenge for large-scale evapotranspiration and root zone soil moisture mapping is to construct a layer stack consisting of N time layers covering the period of interest each containing M pixels covering the region of interest. We will present examples of the Phoenix Active Management Area in AZ (14,600 km2), Green River Basin in WY (44,000 km2), the Kishwaukee Watershed in IL (3,150 km2), the area covered by Landsat Path 28/Row 35 in OK (30,000 km2) and the Agua Salud Watershed in Panama (200 km2). In these regions we used Landsat or MODIS imagery for mapping evapotranspiration and root zone soil moisture by the algorithm Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC) together with meteorological measurements and sometimes either Large Aperture Scintillometers (LAS) or Eddy Covariance (EC). We conclude with lessons learned for future large-scale hydrological studies.

  8. Health effects following subacute exposure to geogenic dusts from arsenic-rich sediment at the Nellis Dunes Recreation Area, Las Vegas, NV.

    PubMed

    DeWitt, Jamie; Buck, Brenda; Goossens, Dirk; Hu, Qing; Chow, Rebecca; David, Winnie; Young, Sharon; Teng, Yuanxin; Leetham-Spencer, Mallory; Murphy, Lacey; Pollard, James; McLaurin, Brett; Gerads, Russell; Keil, Deborah

    2016-08-01

    Geogenic dust from arid environments is a possible inhalation hazard for humans, especially when using off-road vehicles that generate significant dust. This study focused on immunotoxicological and neurotoxicological effects following subacute exposure to geogenic dust generated from sediments in the Nellis Dunes Recreation Area near Las Vegas, Nevada that are particularly high in arsenic; the naturally-occurring arsenic concentrations in these surficial sediments ranged from 4.8 to 346μg/g. Dust samples from sediments used in this study had a median diameter of 4.5μm and also were a complex mixture of naturally-occurring metals, including aluminum, vanadium, chromium, manganese, iron, cobalt, copper, zinc, strontium, cesium, lead, uranium, and arsenic. Adult female B6C3F1 mice exposed via oropharyngeal aspiration to 0.01 to 100mg dust/kg body weight, four times, a week apart, for 28days, were evaluated 24h after the last exposure. Peripheral eosinophils were increased at all concentrations, serum creatinine was dose responsively increased beginning at 1.0mg/kg/day, and blood urea nitrogen was decreased at 10 and 100mg/kg/day. Antigen-specific IgM responses and natural killer cell activity were dose-responsively suppressed at 0.1mg/kg/day and above. Splenic CD4+CD25+ T cells were decreased at 0.01, 0.1, 10, and 100mg/kg/day. Antibodies against MBP, NF-68, and GFAP were selectively reduced. A no observed adverse effect level of 0.01mg/kg/day and a lowest observed adverse effect level of 0.1mg/kg/day were determined from IgM responses and natural killer cell activity, indicating that exposure to this dust, under conditions similar to our design, could affect these responses.

  9. Immunotoxicological and neurotoxicological profile of health effects following subacute exposure to geogenic dust from sand dunes at the Nellis Dunes Recreation Area, Las Vegas, NV.

    PubMed

    Keil, Deborah; Buck, Brenda; Goossens, Dirk; Teng, Yuanxin; Leetham, Mallory; Murphy, Lacey; Pollard, James; Eggers, Margaret; McLaurin, Brett; Gerads, Russell; DeWitt, Jamie

    2016-01-15

    Exposure to geogenic particulate matter (PM) comprised of mineral particles has been linked to human health effects. However, very little data exist on health effects associated with geogenic dust exposure in natural settings. Therefore, we characterized particulate matter size, metal chemistry, and health effects of dust collected from the Nellis Dunes Recreation Area (NDRA), a popular off-road vehicle area located near Las Vegas, NV. Adult female B6C3F1 mice were exposed to several concentrations of mineral dust collected from active and vegetated sand dunes in NDRA. Dust samples (median diameter: 4.4 μm) were suspended in phosphate-buffered saline and delivered at concentrations ranging from 0.01 to 100 mg dust/kg body weight by oropharyngeal aspiration. ICP-MS analyses of total dissolution of the dust resulted in aluminum (55,090 μg/g), vanadium (70 μg/g), chromium (33 μg/g), manganese (511 μg/g), iron (21,600 μg/g), cobalt (9.4 μg/g), copper (69 μg/g), zinc (79 μg/g), arsenic (62 μg/g), strontium (620 μg/g), cesium (13 μg/g), lead 25 μg/g) and uranium (4.7 μg/g). Arsenic was present only as As(V). Mice received four exposures, once/week over 28-days to mimic a month of weekend exposures. Descriptive and functional assays to assess immunotoxicity and neurotoxicity were performed 24 h after the final exposure. The primary observation was that 0.1 to 100 mg/kg of this sand dune derived dust dose-responsively reduced antigen-specific IgM antibody responses, suggesting that dust from this area of NDRA may present a potential health risk.

  10. The Ordovician Las Chacritas pluton (Sierra de Humaya, NW Argentina): origin and emplacement triggered by lateral shortening and magmatic stoping at mid-crustal level

    NASA Astrophysics Data System (ADS)

    Larrovere, Mariano A.; Alasino, Pablo H.; de los Hoyos, Camilo R.; Willner, Arne P.

    2015-04-01

    Field relationships and structural studies combined with in situ U-Th-Pb dating of monazite from Las Chacritas pluton (LCP), Sierra de Humaya, provide insight into the emplacement of peraluminous magmas triggered by lateral shortening of the host rock and magmatic stoping at a mid-crustal level of a retro-arc zone in a convergent orogen. Modal and chemical compositions indicate that the LCP is composed of two main igneous units of peraluminous granitoids. The predominant two-mica granitoids were generated by interaction of crustal rocks with mafic or mafic-derived magmas and/or crystal-rich magmas that entrained residual phases, whereas less abundant leucocratic granitoids may have been originated by partial melting of metasedimentary rocks. The calculated crystallization age of 474 ± 4 Ma is consistent with Ordovician ages (477-470 Ma) of the high-grade metamorphic rocks, indicating concomitant magmatism and metamorphism during the Famatinian orogeny. The LCP was emplaced in the middle crust at a maximum depth of ~14.5 km, where attendant fracturing and ductile deformation were active. Field evidence shows strong temporal and spatial relationships between host rock ductile deformation and the emplacement of the pluton such as folding and strike deflection of the host rock layering and folded concordant leucocratic sheets with magmatic fabrics. This suggests that material transfer processes like lateral wall rock displacement (lateral shortening) was a viable mechanism for the emplacement of the LCP. However, cross-sectional restoration and field evidence such as wall rock xenoliths and intrusive truncations of the host rock foliation and fold traces suggest that magmatic stoping was a complementary mechanism to create the necessary space for the emplacement of the LCP. This work supports previous studies showing that participation of multiple material transfer processes are the rule rather than the exception in the emplacement of plutons.

  11. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P 2O 5 and TiO 2 nucleants

    NASA Astrophysics Data System (ADS)

    Ananthanarayanan, A.; Kothiyal, G. P.; Montagne, L.; Revel, B.

    2010-06-01

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li 2O-4.0Al 2O 3-68.6SiO 2-3.0K 2O-2.6B 2O 3-0.5P 2O 5-0.9TiO 2 was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by 29Si, 31P, 11B and 27Al MAS-NMR. XRD and 29Si NMR showed that lithium metasilicate (Li 2SiO 3) is the first phase to c form followed by cristobalite (SiO 2) and lithium disilicate (Li 2Si 2O 5). 29Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 °C. Since crystalline Li 3PO 4, as observed by 31P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li 3PO 4 does not act as a nucleating agent for lithium silicate phases. Moreover, 31P NMR indicates the formation of M-PO 4 ( M=B, Al or Ti) complexes. The presence of BO 3 and BO 4 structural units in all the glass/glass-ceramic samples is revealed through 11B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO 3) increases at the expense of tetrahedrally coordinated B (BO 4). The 27Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization.

  12. [Necrophilous beetles diversity (Coleoptera: Scarabaeidae, Silphidae, Staphylinidae and Trogidae) in a semiarid area of Zapotitlán de las Salinas Valley, Puebla, México].

    PubMed

    Jiménez-Sánchez, Esteban; Quezada-García, Roberto; Padilla-Ramírez, Jorge

    2013-09-01

    Mexico is constituted of arid and semiarid areas in more than half of its land extension, where most of their resources are available only during the rainy season. For those species that recycle resources, such as the carrion fauna, this represents a highly active season; however, the biological and diversity patterns of carrion fauna are poorly understood in these areas. Here, we studied the abundance, diversity and richness of the Scarabaeidae, Silphidae, Staphylinidae and Trogidae families in the Zapotitlán de las Salinas Valley in Puebla, Mexico. Over a one-year period, monthly samples were collected from five different vegetation systems that included the scrublands, a columnar cactus landscape, and altered vegetation. Samples were collected with the use of NTP-80 traps baited with squid, and data on abundance and richness were obtained and evaluated, with respect to monthly precipitation and sampling site location. We collected a total of 613 insects from 12 genera and 15 species. Across systems, Staphylinidae showed the greatest richness (nine species) and abundance (74.2%), followed by Scarabaeidae (21.9%), Silphidae (2.9%) and Trogidae (1%). Significant differences were observed between sites and months; nevertheless, no relationship was observed between abundance and temperature or precipitation. Across taxonomic groups, abundance and richness were most evident for scrub sites, while a greater abundance during the dry season was obtained. The results of this study indicated that the carrion faunal community composition is closely related to the type of vegetation and did not depend on the rainy season. In spite that lesser carrion fauna was observed in this area when compared to other regions of Mexico, this report constitutes a significant contribution to our understanding of the ecological role of this fauna in arid areas.

  13. Infrared Camera Characterization of Bi-Propellant Reaction Control Engines during Auxiliary Propulsion Systems Tests at NASA's White Sands Test Facility in Las Cruces, New Mexico

    NASA Technical Reports Server (NTRS)

    Holleman, Elizabeth; Sharp, David; Sheller, Richard; Styron, Jason

    2007-01-01

    This paper describes the application of a FUR Systems A40M infrared (IR) digital camera for thermal monitoring of a Liquid Oxygen (LOX) and Ethanol bi-propellant Reaction Control Engine (RCE) during Auxiliary Propulsion System (APS) testing at the National Aeronautics & Space Administration's (NASA) White Sands Test Facility (WSTF) near Las Cruces, New Mexico. Typically, NASA has relied mostly on the use of ThermoCouples (TC) for this type of thermal monitoring due to the variability of constraints required to accurately map rapidly changing temperatures from ambient to glowing hot chamber material. Obtaining accurate real-time temperatures in the JR spectrum is made even more elusive by the changing emissivity of the chamber material as it begins to glow. The parameters evaluated prior to APS testing included: (1) remote operation of the A40M camera using fiber optic Firewire signal sender and receiver units; (2) operation of the camera inside a Pelco explosion proof enclosure with a germanium window; (3) remote analog signal display for real-time monitoring; (4) remote digital data acquisition of the A40M's sensor information using FUR's ThermaCAM Researcher Pro 2.8 software; and (5) overall reliability of the system. An initial characterization report was prepared after the A40M characterization tests at Marshall Space Flight Center (MSFC) to document controlled heat source comparisons to calibrated TCs. Summary IR digital data recorded from WSTF's APS testing is included within this document along with findings, lessons learned, and recommendations for further usage as a monitoring tool for the development of rocket engines.

  14. 1-Dodecane-sulfonic-acid-sodium-salt(LAS) assisted hydrothermal synthesis of Cd{sub x}Zn{sub 1-x}S solid solution as efficient photocatalysts under visible light irradiation

    SciTech Connect

    Jia, B.; Guo, L. J.

    2010-03-01

    With anionic surfactant LAS assisted, series of zinc cadmium sulfide semiconductor photocatalysts were synthesized by hydrothermal method. These products were characterized by X-ray diffraction (XRD), UV-Vis absorption spectra (UV-Vis) and scanning electron microscopy (FESEM). The photocatalytic activities of as-prepared samples were evaluated by photocatalytic hydrogen production from water under visible-light irradiation. The best synthesis parameters are: Composition 0.9:0.1 (Cd:Zn molar ratio), Temperature 160 deg. C, Hydrothermal Time 48 Hour, LAS Concentration 1.7 mmol/L, the maximum visible-light-catalytic hydrogen production rate is 161.25 {mu}mol/h (lambda>430 nm) which is higher than those of by coprecipitation method. The experiment results indicate that surfactant assisted hydrothermal method is an effective way to get highly active CdZnS solid solution photocatalyst.

  15. Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa.

    PubMed

    Pessi, G; Haas, D

    2000-12-01

    Virulence factors of Pseudomonas aeruginosa include hydrogen cyanide (HCN). This secondary metabolite is maximally produced at low oxygen tension and high cell densities during the transition from exponential to stationary growth phase. The hcnABC genes encoding HCN synthase were identified on a genomic fragment complementing an HCN-deficient mutant of P. aeruginosa PAO1. The hcnA promoter was found to be controlled by the FNR-like anaerobic regulator ANR and by the quorum-sensing regulators LasR and RhlR. Primer extension analysis revealed two transcription starts, T1 and T2, separated by 29 bp. Their function was confirmed by transcriptional lacZ fusions. The promoter sequence displayed an FNR/ANR box at -42.5 bp upstream of T2 and a lux box centered around -42.5 bp upstream of T1. Expression of the hcn genes was completely abolished when this lux box was deleted or inactivated by two point mutations in conserved nucleotides. The lux box was recognized by both LasR [activated by N-(oxododecanoyl)-homoserine lactone] and RhlR (activated by N-butanoyl-homoserine lactone), as shown by expression experiments performed in quorum-sensing-defective P. aeruginosa mutants and in the N-acyl-homoserine lactone-negative heterologous host P. fluorescens CHA0. A second, less conserved lux box lying 160 bp upstream of T1 seems to account for enhanced quorum-sensing-dependent expression. Without LasR and RhlR, ANR could not activate the hcn promoter. Together, these data indicate that expression of the hcn promoter from T1 can occur under quorum-sensing control alone. Enhanced expression from T2 appears to rely on a synergistic action between LasR, RhlR, and ANR.

  16. Transcriptional Control of the Hydrogen Cyanide Biosynthetic Genes hcnABC by the Anaerobic Regulator ANR and the Quorum-Sensing Regulators LasR and RhlR in Pseudomonas aeruginosa

    PubMed Central

    Pessi, Gabriella; Haas, Dieter

    2000-01-01

    Virulence factors of Pseudomonas aeruginosa include hydrogen cyanide (HCN). This secondary metabolite is maximally produced at low oxygen tension and high cell densities during the transition from exponential to stationary growth phase. The hcnABC genes encoding HCN synthase were identified on a genomic fragment complementing an HCN-deficient mutant of P. aeruginosa PAO1. The hcnA promoter was found to be controlled by the FNR-like anaerobic regulator ANR and by the quorum-sensing regulators LasR and RhlR. Primer extension analysis revealed two transcription starts, T1 and T2, separated by 29 bp. Their function was confirmed by transcriptional lacZ fusions. The promoter sequence displayed an FNR/ANR box at −42.5 bp upstream of T2 and a lux box centered around −42.5 bp upstream of T1. Expression of the hcn genes was completely abolished when this lux box was deleted or inactivated by two point mutations in conserved nucleotides. The lux box was recognized by both LasR [activated by N-(oxododecanoyl)-homoserine lactone] and RhlR (activated by N-butanoyl-homoserine lactone), as shown by expression experiments performed in quorum-sensing-defective P. aeruginosa mutants and in the N-acyl-homoserine lactone-negative heterologous host P. fluorescens CHA0. A second, less conserved lux box lying 160 bp upstream of T1 seems to account for enhanced quorum-sensing-dependent expression. Without LasR and RhlR, ANR could not activate the hcn promoter. Together, these data indicate that expression of the hcn promoter from T1 can occur under quorum-sensing control alone. Enhanced expression from T2 appears to rely on a synergistic action between LasR, RhlR, and ANR. PMID:11092854

  17. Efectos combinados de la ampliación de la atención primaria de salud y de las transferencias condicionadas de dinero en efectivo sobre la mortalidad infantil en Brasil, 1998–2010*

    PubMed Central

    Guanais, Frederico C.

    2015-01-01

    Objetivos. Examiné los efectos combinados del acceso a la atención primaria mediante el Programa de Salud Familiar (PSF) y las transferencias condicionadas de dinero en efectivo del Programa Bolsa Familia (PBF) sobre la mortalidad infantil posneonatal (MIPN) en Brasil. Métodos. Empleé un análisis ecológico longitudinal usando datos en panel de 4 583 municipios brasileños de 1998 al 2010, con 54 253 observaciones en total. Estimé modelos de regresión de efectos fijos por mínimos cuadrados ordinarios, con la tasa de MIPN como la variable dependiente y el PSF, el PBF y sus interacciones como las principales variables independientes de interés. Resultados. La asociación de una mayor cobertura del PSF con una menor tasa de MIPN se volvió más fuerte conforme aumentaba la cobertura del PBF. En los promedios de todas las demás variables, cuando la cobertura de PBF era 25%, la MIPN predicha fue 5,24 (intervalo de confianza [IC] de 95% = 4,95, 5,53) para una cobertura del PSF de 0%, y de 3,54 (IC de 95% = 2,77, 4,31) para una cobertura del PSF de 100%. Cuando la cobertura del PBF era de 60%, la MIPN predicha fue 4,65 (IC de 95% = 4,36, 4,94) para una cobertura del PSF de 0%, y de 1,38 (IC de 95% = 0,88, 1,89) para una cobertura del PSF de 100%. Conclusiones. El efecto del PSF depende de la ampliación del PBF. Para las poblaciones empobrecidas y subatendidas, la combinación de intervenciones tanto del lado de la oferta como del lado de la demanda podría ser necesaria para mejorar los resultados en salud.

  18. Environmental Baseline Survey, Real Property Transaction Between Nellis Air Force Base and the City of North Las Vegas for Construction of a Wastewater Treatment Facility, Clark County, Nevada. Phase 1

    DTIC Science & Technology

    2007-12-06

    FINAL PHASE I ENVIRONMENTAL BASELINE SURVEY REAL PROPERTY TRANSACTION BETWEEN NELLIS AIR FORCE BASE AND THE CITY OF NORTH LAS...4. TITLE AND SUBTITLE Final Phase I Environmental Baseline Survey Real Property Transaction Between Nellis Air Force Base and the City of North...6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Nellis Air Force Base 8

  19. Application of the New Propulsion Theory to the Design of Propellers. Comparison with the Lifting Line Theory (Aplicacion de la Nueva Teoria de la Impulsion al Diseno de Propulsores. Comparacion con la Teoria de las Lineas Sustentadoras),

    DTIC Science & Technology

    1983-11-07

    Results and Improvement Thereon," Ingenieria Naval, May 1978. 11. Perez Gomez, G., "Fundamentos teoricos de los modernos procedimientos de proyecto de...TRANSLATED BY: 9198 SOJRCE: INGENIERIA NAVAL, JULY 1983, PP. 267-278; SPANISH DTICSELECTE DEC 9 I983 ~D MWS TRANSLATION No 72D DATE 7 NOVEMBER 1903 [-M...Impulsion al Diseno de Propulsores. Comparacion con la Teoria de las Lineas Sustentadoras.; Ingenieria Naval, July 1983; pp. 267-278] *Department of Ship

  20. Derivation of predicted no effect concentrations (PNEC) for marine environmental risk assessment: application of different approaches to the model contaminant Linear Alkylbenzene Sulphonates (LAS) in a site-specific environment.

    PubMed

    Hampel, M; González-Mazo, E; Vale, C; Blasco, J

    2007-05-01

    Four sediment-dwelling marine organisms were exposed to sediments spiked with increasing concentrations of Linear Alkylbenzene Sulphonate (LAS). The selected endpoint mortality was reported daily and acute LC(50) (96 h), as well as final LC(10) values were calculated for the derivation of environmentally safe predicted no effect concentrations (PNEC) for the sediment compartment. PNECs were estimated by both application of assessment factors (AF) and the equilibrium partitioning method (EPM) as proposed by the EU TGD. Finally, environmental risk assessment in a site-specific environment, the Sancti Petri Channel, South Iberian Peninsula, was carried out at three different sampling stations with known environmental LAS concentrations. PNECs obtained by the assessment factor approach with acute toxicity data were one to two orders of magnitude lower than those from the equilibrium partitioning method. On the other hand, when applying lower AFs to the estimated LC(10) values, the PNECs obtained by both approaches were more similar. Environmental risk assessment carried out with the estimated PNECs in a site specific environment with known sediment LAS concentrations revealed that PNECs obtained with acute toxicity data were over conservative whereas those obtained with AF=10 on LC(10) data and EPM produced more realistic results in accordance with field observations carried out in the study area.

  1. Single-particle laser-induced-fluorescence spectra of biological and other organic-carbon aerosols in the atmosphere: Measurements at New Haven, Connecticut, and Las Cruces, New Mexico

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le; Pinnick, Ronald G.; Hill, Steven C.; Rosen, James M.; Chang, Richard K.

    2007-12-01

    This study focuses on organic carbon (OC) aerosols, including natural biological aerosols, in the Earth's troposphere, and on laser-induced fluorescence (LIF) spectral methods for studying these aerosols. LIF spectra of atmospheric OC and biological aerosols (having diameters greater than approximately 3 μm) measured at New Haven, Connecticut, and Las Cruces, New Mexico, are reported. A hierarchical clustering method was used to cluster approximately 90% of the single-particle LIF spectra into 8-10 groups. Some of these groups have spectra that are similar to spectra of some important classes of atmospheric aerosol, such as humic/fulvic acids and humic-like substances, bacteria, cellulose, marine aerosol, and polycyclic aromatic hydrocarbons (PAH). A comparison with previous measurements made at Adelphi, Maryland, reveals that the most highly populated clusters found at Adelphi, and some of the less populated ones, also appear in the LIF spectra at New Haven and Las Cruces, even though the regional climates at these locations is different (New England/Atlantic Coastal, for New Haven and Adelphi, and Chihuahuan Desert for Las Cruces), and the measurements were made in different seasons. The results are consistent with some (perhaps most) of the fluorors in OC and biological atmospheric aerosols being common to these three sites. On average, spectra characteristic of humic/fulvic acids and humic-like substances (HULIS) comprise 28-43% of fluorescent particles at all three sites; whereas cellulose-like spectra contribute only 1-3%.

  2. Estudio comparativo de las moléculas isovalentes de interés atmosférico CF3Cl y CF3Br y sus correspondientes halógenos aislados Cl y Br.

    NASA Astrophysics Data System (ADS)

    Mayor, E.; Velasco, A. M.; Martín, I.; Lavín, C.

    Los estados Rydberg moleculares han suscitado en los últimos años un creciente interés entre los espectroscopistas experimentales, motivado en parte por el desarrollo de nuevas técnicas espectroscópicas capaces de investigar estos estados altamente excitados electrónicamente. Los procesos de fotoabsorción que implican estados Rydberg en los derivados halogenados del metano son de gran importancia, debido a su abundancia en la atmósfera y a sus implicaciones medioambientales. Por ello, la obtención de datos relativos a sus fuerzas de oscilador es de gran interés. En este trabajo se aborda el estudio de dichas propiedades para las moléculas isovalentes CF3Cl y CF3Br. Ambas moléculas presentan idéntica estructura electrónica para el estado fundamental por lo que se espera que sus espectros Rydberg presenten grandes similitudes, en ausencia de perturbaciones. Por ello y dada la escasez de datos relativos a fuerzas de oscilador, hemos establecido la corrección de nuestros resultados en base a las analogías esperadas en las intensidades espectrales correspondientes a transiciones análogas. Por otro lado, Novak y col. [1] han encontrado experimentalmente un marcado carácter atómico en el espectro correspondiente a estas moléculas, siendo muy similar a los de los átomos de Cl y Br. Por ello en el presente trabajo, además de establecer la comparación entre ambas moléculas hemos buscado las similitudes con sus respectivos halógenos. Los cálculos relativos a las especies moleculares se han realizado utilizando la Metodología Molécular de Orbítales de Defecto Cuántico (MQDO) [2], mientras que para el estudio de los átomos de Cl y Br se empleó la versión relativista del método (RQDO) [3].

  3. Mechanized and natural soil-to-air transfer of trifluralin and prometryn from a cotton field in Las Cruces, New Mexico.

    PubMed

    Holmén, Britt A; Kasumba, John; Hiscox, April; Wang, Junming; Miller, David

    2013-10-16

    Two pre-emergence herbicides (trifluralin and prometryn) were applied on a cotton field in Las Cruces, New Mexico, and their atmospheric particle and gas-phase concentrations were measured during mechanized soil preparation and natural wind erosion sampling events before and after herbicide application. Air sampling was conducted using samplers mounted at various heights from the ground and at various locations on the field. During mechanized soil management with a disk harrow, sampling occurred at two distances from the tractor ("near-source", 4 m downwind and "far-source", 20-100 m from the disking tractor). Natural background (no disking) sampling events occurred during daytime and at night. Both herbicides were quantifiable for all postapplication sampling events, including background sampling that occurred 8, 38, and 40 days after herbicide application. Average concentrations in both the gas and particle phases ranged from about 10 to 350 ng/m(3). Averaging by event type, mean total prometryn concentrations were 2 (night background) to 8 (near-source) times higher than the corresponding trifluralin concentrations. Prometryn/trifluralin ratios were higher in airborne samples than in soil, indicative of trifluralin losses during daytime sampling, possibly via atmospheric reactions. Prometryn particle phase mass fractions were generally higher than those for trifluralin for all sampling events, consistent with Kair/soil-oc partition coefficients, and particle-phase mass fractions were higher for near-source disking and daytime background sampling compared to far-source and nighttime. Daytime natural background prometryn concentrations could be as high as those measured during disking, and background samples showed significant relationships to meteorological parameters (air temperature, relative humidity, and dewpoint). Mechanical disturbance by tilling operations reduced the ability to predict airborne herbicide concentrations on the basis of meteorological

  4. Assessment of the vegetation cover in a burned area 22-years ago using remote sensing techniques and GIS analysis (Sierra de las Nieves, South of Spain).

    NASA Astrophysics Data System (ADS)

    Martínez-Murillo, Juan F.; Remond, Ricardo; Ruiz-Sinoga, José D.

    2015-04-01

    The study aim was to characterize the vegetation cover in a burned area 22-years ago considering the previous situation to wildfire in 1991 and the current one in 2013. The objectives were to: (i) compare the current and previous vegetation cover to widlfire; (ii) evaluate whether the current vegetation has recovered the previous cover to wildfire; and (iii) determine the spatial variability of vegetation recovery after 22-years since the wildfire. The study area is located in Sierra de las Nieves, South of Spain. It corresponds to an area affected by a wildfire in August 8th, 1991. The burned area was equal to 8156 ha. The burn severity was spatially very high. The main geographic features of the burned area are: mountainous topography (altitudes ranging from 250 m to 1500 m; slope gradient >25%; exposure mainly southfacing); igneous (peridotites), metamorphic (gneiss) and calcareous rocks (limestones); and predominant forest land use (Pinus pinaster sp. woodlands, 10%; pinus opened forest + shrubland, 40%; shrubland, 35%; and bare soil + grassland, 15%). Remote sensing techniques and GIS analysis has been applied to achieve the objectives. Landsat 5 and Landsat 8 images were used: July 13th, 1991 and July 1st, 2013, for the previous wildfire situation and 22-years after, respectively. The 1990 CORINE land cover was also considered to map 1991 land uses prior the wildfire. Likewise, the Andalucía Regional Government wildfire historic records were used to select the burned area and its geographical limit. 1991 and 2013 land cover map were obtained by means of object-oriented classifications. Also, NDVI and PVI1 vegetation indexes were calculated and mapped for both years. Finally, some images transformations and kernel density images were applied to determine the most recovered areas and to map the spatial concentration of bare soil and pine cover areas in 1991 and 2013, respectively. According to the results, the combination of remote sensing and GIS analysis let

  5. Creating an evidence-based admissions formula for a new dental school: University of Nevada, Las Vegas, School of Dental Medicine.

    PubMed

    Kingsley, Karl; Sewell, Jeremy; Ditmyer, Marcia; O'Malley, Susan; Galbraith, Gillian M

    2007-04-01

    This article reports development of an evidence-based admissions formula that effectively incorporates the admissions criteria most likely to influence dental school performance. This study utilized peer-reviewed literature and analysis of admissions and performance data from the first three classes of students at the University of Nevada, Las Vegas, School of Dental Medicine (UNLV-SDM). We used Pearson's correlation, linear regression, and ANOVA to determine the strength and direction of association between admissions variables, both singly and in combination, and performance measures. Our initial results revealed no significant relationship between our previous admissions formula, which was adapted from other dental admissions offices, and student performance for our first class and National Board Dental Examination Part I (NBDE-I) (R=.288) or dental school grade point average (DS-GPA) (R=0.193). After using the combined data from the first three classes of students at UNLV-SDM, we confirmed no significant relationship between our previous admissions formula and DS-GPA (R=0.207) and a slight increase in correlation to NBDE-I (R=0.303). More detailed analysis of the admissions variables within the formula revealed that some Dental Admission Test scores, such as Reading Comprehension, Quantitative Analysis, and Biology, were significantly correlated with dental school performance at UNLV-SDM, allowing for revision of the admissions formula to a formula score that is now significantly correlated with student performance for the first class to NBDE-I (R=0.458) and DS-GPA (R=0.368), as well as the combined data from the first three cohorts at UNLV-SDM (R=0.361, 0.218, respectively). In addition, this reformulation did not significantly impact the overall ranking of females or minorities. Although formulaic data can never perfectly predict student performance, this study demonstrated that constant review and revision of relevant admissions criteria are needed for each

  6. Ground-water quality and geochemistry of Las Vegas Valley, Clark County, Nevada, 1981-83; implementation of a monitoring network

    USGS Publications Warehouse

    Dettinger, M.D.

    1987-01-01

    As a result of rapid urban growth in Las Vegas Valley, rates of water use and wastewater disposal have grown rapidly during the last 25 years. Concern has developed over the potential water quality effects of this growth. The deep percolation of wastewater and irrigation return flow (much of which originates as imported water from Lake Mead), along with severe overdraft conditions in the principal aquifers of the valley, could combine to pose a long-term threat to groundwater quality. The quantitative investigations of groundwater quality and geochemical conditions in the valley necessary to address these concerns would include the establishment of data collection networks on a valley-wide scale that differ substantially from existing networks. The valley-wide networks would have a uniform areal distribution of sampling sites, would sample from all major depth zones, and would entail repeated sampling from each site. With these criteria in mind, 40 wells were chosen for inclusion in a demonstration monitoring network. Groundwater in the northern half of the valley generally contains 200 to 400 mg/L of dissolved solids, and is dominated by calcium, magnesium , and bicarbonate ions, reflecting a chemical equilibrium between the groundwater and the dominantly carbonate rocks in the aquifers of this area. The intermediate to deep groundwater in the southern half of the valley is of poorer quality (containing 700 to 1,500 mg/L of dissolved solids) and is dominated by calcium, magnesium, sulfate, and bicarbonate ions, reflecting the occurrence of other rock types including evaporite minerals among the still-dominant carbonate rocks in the aquifers of this part of the valley. The poorest quality groundwater in the valley is generally in the lowland parts of the valley in the first few feet beneath the water table, where dissolved solids concentrations range from 2,000 to > 7,000 mg/L , and probably reflects the effects of evaporite dissolution, secondary recharge, and

  7. Deep Seismic Imaging of the Crust Through Las Cárceles and Bajada de Añelo, Neuquén Basin - Argentina (38° SL)

    NASA Astrophysics Data System (ADS)

    Comínguez, A.; Franzese, J.

    2002-12-01

    Deep seismic sections were obtained by mathematical reprocessing of conventional vibroseis data recorded in the central sector of the Neuquén Basin. The lines involved linear upsweeps with frequency band of 12-65Hz and time-length of 8 sec. The field records were characterized by time-lengths of 13 sec and a sampling period of 4 msec . The Self-Truncating Extended Correlation algorithm was used to compute cross-correlation between the sweep and the records. The original frequency-band of 12-65 Hz was preserved for the first 5 sec of trace. However, this band was affected by an upper-frequency decreasing from 5 sec on, at a predicted linear-rate of 6.625 Hz/sec. Hence, correlated deep-records with a time-length of 11 sec and a final trace-band of 12-25 Hz were calculated. Depth-migration was implemented on the extended traces. Consequently, progressive models of crust velocity were iteratively matched with the corresponding migrated log. The iterative process was considered concluded when it was observed acceptable coincidence between the model and the depth-migrated horizons. The basin stratigraphy in the area consists of a continental sequence of initial sinrift (Precuyano) deposited on halfgrabens, followed by strong cycles of marine and continental postrift units (Cuyo, Lotena, and Mendoza groups). The initial structuration is considered of Superior Triassic-Liasic age. While, the postrif phase would have extended until Early Cretaceous. The analysis in the area of Las Cárceles reveals the following:(1)The lower-crust top is placed at about 23-24 km;(2)An oblique reflector horizon between 16 and 18 km depth, is considered as a master shear that controlled the extensional system;(3)A submaster fault, between 8.5 and 12 km depth, is partially recognized in seismic sections;(4)The top of the rift basemen is characterized by irregular depths that, from W to E, fluctuates from 9 to 5 km;(5)Evident features of tectonic inversion, including sinrift as well as part of

  8. Seismic investigation of the buried horst between the Jornada del Muerto and Mesilla ground-water basins near Las Cruces, Dona Ana County, New Mexico

    USGS Publications Warehouse

    Woodward, D.G.; Myers, R.G.

    1997-01-01

    Six seismic reflection profiles were collected in the vicinity of the Jornada Horst between Goat Mountain and Tortugas Mountain (northeast and east of Las Cruces, New Mexico) to delineate more precisely the geometry of the horst and to determine whether large, buried channels have been incised into the top of the horst. The Jornada fault zone separates the southern Jornada del Muerto ground-water basin from the Mesilla ground-water basin in the Mesilla drainage basin. The upper part of the Jornada Horst is composed of Tertiary volcanic and volcaniclastic rocks; these rocks overlie Permian sedimentary rocks. The horst, in turn, is overlain by unconsolidated sediments of the upper Santa Fe Group. Some test holes indicate that little or no ground water flows from the Jornada del Muerto ground-water basin to the Mesilla ground-water basin over some portions of the horst. However, some ground water flows through the upper Santa Fe Group deposits above some portions of the horst. Ground-water flow immediately east of the horst near U.S. Highway 70 is deflected northward in the southern Jornada del Muerto ground-water basin presumably because of the change from higher hydraulic-conductivity values of aquifer materials in the southern basin to lower hydraulic-conductivity values of materials in the horst. Incised, buried channels, if present on the horst, could be filled with alluvial material with higher hydraulic- conductivity values than those of the material in the horst. Incised, buried channels would allow ground water to readily move from the Jornada del Muerto ground-water basin to the Mesilla ground-water basin. The gross geometry of the horst--eastern extent, constraints on the western extent, and general altitude of the top--was discerned by interpretations of the seismic profiles. The presence or absence of large channels incised into the top of the horst could not be confirmed by these interpretations. However, the seismic interpretations suggest that the

  9. Structural analysis and shape-preferred orientation determination of the mélange facies in the Chañaral mélange, Las Tórtolas Formation, Coastal Cordillera, northern Chile

    NASA Astrophysics Data System (ADS)

    Fuentes, Paulina; Díaz-Alvarado, Juan; Fernández, Carlos; Díaz-Azpiroz, Manuel; Rodríguez, Natalia

    2016-04-01

    This study sheds light on the tectonic and structural knowledge of the mélange facies located to the south of Chañaral city, Chile. The Chañaral mélange has been related to an accretionary prism at the western active continental margin of Gondwana. Based on the fossil content, the original turbidite sequence would have been deposited during Devonian to Carboniferous times. The Chañaral mélange is included in the Las Tórtolas Formation, which corresponds to the Paleozoic metasedimentary basement located in the Coastal Range in northern Chile. It consists of a monotonous sequence of more than 90% of interbedded sandstones and shales, with a few limestones, pelagic chert, conglomerates and basic volcanic rocks, metamorphosed to the greenschist facies. In the study area, the Las Tórtolas Formation is divided into two structural domains separated by a major reverse dextral structure, called here the Infieles fault. To the east, the Las Tórtolas Formation is characterized by a brittle-ductile deformation, defined by the original sedimentary contacts in the turbiditic sequence. Besides, thrust faults and associated thrust propagation folds promotes a penetrative axial plane foliation. Mélange facies are located to the west of the Infieles fault. Although lithologies comprising this domain are similar to the rest of the Las Tórtolas Formation, mélange facies (ductile domain) are characterized by the complete disruption of the original architecture of the turbidite succession. The most significant structures in the mélange are the ubiquitous boudinage and pinch and swell structures, asymmetric objects, S-C structures and tight to isoclinal folds. This deformation is partitioned in the Chañaral mélange between linear fabric domains (L), characterized by quartzite blocks with prolate shape in a phyllite matrix with pencil structures, and linear-planar fabric domains (L-S), where quartzite objects show oblate shape and phyllites present a penetrative foliation

  10. Measurement of Black Carbon Particles and their Mixing State in Wildfire Plumes from New Mexico: Aged Whitewater Baldy Complex in 2012 and Fresh Las Conchas in 2011

    NASA Astrophysics Data System (ADS)

    Aiken, A. C.; Dubey, M. K.; Gorkowski, K.; Mazzoleni, C.; China, S.

    2012-12-01

    Approximately 50% of black carbon (BC) aerosols come from wildfires and are estimated to contribute up to ~0.6 W/m2 warming of the atmosphere globally. Organic carbon (OC) from fires condenses and/or mixes with BC resulting in an overall lower forcing of 0.03 ± 0.12 Wm-2 from biomass burning. However, this reduction depends strongly on the composition of the carbonaceous aerosols and on the mixing state of OC and BC. Detailed model treatments and laboratory measurements indicate that a BC core coated with a non-absorbing OC layer enhances absorption with a positive climate forcing. However, the real-time identification of the coating on this internally mixed BC in the field has only recently become detectable with the analysis of lag times between the scattering and incandescence signals in measurements from the single particle soot photometer (SP2). While fully coated BC has a positive lag time (cBC) in the SP2 data, BC that is located near the surface (nsBC) is associated with a negative lag time (Sedlacek et al. 2012). We investigate BC mixing states in concentrated wildfire plumes from the two largest wildfires in New Mexico's history with different ages. Plumes from the Las Conchas (LC) Fire, a wildfire that occurred in July-August of 2011 and burned ~157K acres, were sampled in the near-field after only a few hours of aging. Older plumes from the Whitewater Baldy (WB) Fire (May-June, 2012) that burned ~300K acres were sampled from further afield with an aging period of 7-9 hours. We find up to 23% of the internally mixed BC to be nsBC in the older WB plume. The nsBC fraction is smaller for the relatively fresh LC plume. Figure 1 shows %nsBC versus plume age as a conceptual framework of increasing %nsBC with age for the wildfire data shown here. SP2 results are corroborated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of single particles collected on nuclepore membranes that clearly show the shifts in morphology. Furthermore

  11. NURE aerial gamma-ray and magnetic reconnaissance survey of portions of New Mexico, Arizona and Texas. Volume II. New Mexico-Las Cruces NI 13-10 Quadrangle. Final report

    SciTech Connect

    Not Available

    1981-09-01

    The results of a high-sensitivity, aerial gamma-ray spectrometer and magnetometer survey of the Las Cruces two degree quadrangle, New Mexico, are presented. Instrumentation and methods are described in Volume 1 of this final report. The work was done by Carson Helicopters, Inc., and International Exploration, Inc. The work was performed for the US Department of Energy - National Uranium Resource Evaluation (NURE) program. Analysis of this radiometric data yielded 192 statistically significant eU anomalies. Of this number, thirty-nine were considered to be of sufficient strength to warrant further investigation.

  12. Nesting biology, morphological remarks, and description of the mature larva of Mellinus arvensis obscurus (Hymenoptera: Crabronidae) in Nepal

    SciTech Connect

    Boesi, R.; Polidori, C.; Andrietti, F.; Gayubo, S.F.; Tormos, J.; Asis, J.D.

    2007-03-15

    subespecie de la bien estudiada subespecie nominal. Mellinus arvensis obscurus nidifica a gran altitud, en terreno inclinado, con y sin vegetacion, expuesto en mayor o menor medida al sol y en agregaciones muy compactas. Durante la estacion lluviosa la hembras llevan a cabo pocos vuelos de aprovisonamiento. Las presas pertenecen al orden de los dipteros, aunque, en una ocasion se observo el aporte de una arana. Gran numero de las interacciones intraespecificas observadas sugieren un alto grado de intentos de usurpacion de nidos. Los enemigos naturales mas sobresalientes pertenecen al orden de los dipteros y a la familia de los formicidos. Del estudio morfologico del adulto, mencionaremos que la foma del terguito 1 y la escultura del cuerpo, en las hembras de las poblaciones del Nepal, son mas semejantes a los de las hembras de las poblaciones europeas que no a los de las japonesas. De la fase larvaria se describe el ultimo estado larvario, a la vez que se compara con la otra larva madura ya descrita del genero. Las diferencias entre ambas larvas maduras radican en la presencia/ausencia, numero o diferenciacion de las estructuras tegumentarias. El estudio finaliza concluyendo que los rasgos morfologicos son mas importantes, que los aspectos ecologicos y comportamentales, a la hora de establecer una separacion entre las dos subespecies (author)

  13. Tensile and Fatigue Testing and Material Hardening Model Development for 508 LAS Base Metal and 316 SS Similar Metal Weld under In-air and PWR Primary Loop Water Conditions

    SciTech Connect

    Mohanty, Subhasish; Soppet, William; Majumdar, Saurin; Natesan, Ken

    2015-09-01

    This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in September 2015 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2015 report we presented a baseline mechanistic finite element model of a two-loop pressurized water reactor (PWR) for systemlevel heat transfer analysis and subsequent thermal-mechanical stress analysis and fatigue life estimation under reactor thermal-mechanical cycles. In the present report, we provide tensile and fatigue test data for 508 low-alloy steel (LAS) base metal, 508 LAS heat-affected zone metal in 508 LAS–316 stainless steel (SS) dissimilar metal welds, and 316 SS-316 SS similar metal welds. The test was conducted under different conditions such as in air at room temperature, in air at 300 oC, and under PWR primary loop water conditions. Data are provided on materials properties related to time-independent tensile tests and time-dependent cyclic tests, such as elastic modulus, elastic and offset strain yield limit stress, and linear and nonlinear kinematic hardening model parameters. The overall objective of this report is to provide guidance to estimate tensile/fatigue hardening parameters from test data. Also, the material models and parameters reported here can directly be used in commercially available finite element codes for fatigue and ratcheting evaluation of reactor components under in-air and PWR water conditions.

  14. Pronounced site preference and mixed dinuclear dichalcogenide anions (SSe)2- in ternary lanthanum sulfide selenides - The solid solution LaS1.9-LaSe1.9

    NASA Astrophysics Data System (ADS)

    Bartsch, Christian; Doert, Thomas

    2012-04-01

    Ternary lanthanum sulfide selenides LaS1.9-xSex (0 < x < 1.9) were obtained by reaction of the elements in a potassium bromide flux. The ternary compounds adopt the CeSe1.9 structure type (tetragonal, space group P42/n, No. 86) and form a complete solid solution series without indications of ordered superstructures. The lattice parameters of the samples follow Vegard's rule and are found in the range of 915 ≤ a ≤ 943 pm and 1644 ≤ c ≤ 1703 pm. A pronounced ordering of the distribution of chalcogen atoms is observed which can be attributed to charge density and size effects. The existence of three different types of dichalcogenide anions, namely S22-, Se22- and mixed (SSe)2-, is evidenced by Raman spectroscopy.

  15. The Moon Phases in a Paper Box. (Spanish Title: Las Fases de la Luna en Una Caja de Cartón.) As Fases da Lua Numa Caixa de Papelão

    NASA Astrophysics Data System (ADS)

    de Fátima O. Saraiva, Maria; Amador, Cláudio B.; Kemper, Érico; Goulart, Paulo; Muller, Angela

    2007-12-01

    We present a very simple concrete model to demonstrate the concept of phases of an illuminated body. The main objective of our model is to help the understanding of the Moon phases as viewed from the perspective of an observer on Earth. The material allows the visualization of two important effects: (1st) even though all the time half Moon is illuminated by the Sun, we see different fractions of the illuminated Moon surface, depending on our angle of sight; (2nd) the orientation of the convex part of the Moon in the crescent and waning phases on the sky also depends on our perspective from Earth. The use of a closed box allows one to see the contrast among the different phases with no need of a dark room. We also present a text on the Moon phases, emphasizing the dependence of the aspect of the bright part on the angle of sight. En este trabajo proponemos la construcción de material didáctico de bajo costo para demostración del concepto de fases de un cuerpo iluminado. El principal objetivo de nuestro material es facilitar la comprensión de las fases de la Luna desde la perspectiva de un observador en la Tierra. El material ayuda la visualización de dos efectos importantes: (1º) a pesar de tener siempre la mitad de la Luna (representada por una bolita de espuma plástica o de ping-pong), iluminada por el Sol ( representado por una fuente de luz natural o artificial), vemos diferentes fracciones de su superficie iluminada, dependiendo del ángulo por el cual la vemos; (2º) la orientación del borde convexo de la Luna en las fases Creciente y Menguante también depende de la perspectiva por la cual la miramos desde la Tierra. El uso de una caja cerrada permite observar el contraste entre las diferentes fases sin necesidad de estar en un recinto oscuro. Presentamos también un texto explicativo sobre las fases de la Luna, enfatizando la dependencia de la apariencia de la parte iluminada con el ángulo de visión. Neste trabalho propomos a construção de

  16. High School Students' Previous Knowledge about the Stars. (Spanish Title: Conocimientos Previos de Estudiantes de Secundaria Acerca de Las Estrellas.) O Conhecimento Prévio de Alunos do Ensino Médio sobre as Estrelas

    NASA Astrophysics Data System (ADS)

    Iachel, Gustavo

    2011-12-01

    Based on the readings of articles related to Astronomy Education published in Brazil, it was noticed a lack of research on previous knowledge of students about the physical characteristics of stars, a fact that motivated us to develop this study. Previous knowledge of 125 students (approximated 15 years old) constituted the study sample; data was collected through written questionnaires (Appendix A) for analysis. From the content analysis of these responses it was possible to achieve some inferences as, for example, many students have some difficult to develop an explanatory model on the functioning of a star; there are few who say that the stars have a certain length of existence; some students have said that stars have tips; few recognize that a star is formed by a mass of gas; some previous knowledge come from purely visual aspects; furthermore, some students do not have the habit of observing nature in detail. We see this research as a reference in which science teachers can recognize the importance of previous knowledge for practice teaching and acquire resources for planning their lessons. De la lectura de artículos relacionados con la Educación en Astronomía publicados en el Brasil, se encuentra una falta de investigaciones acerca del conocimiento previo de los estudiantes sobre las características físicas de las estrellas, hecho que nos motivó a desarrollar este estudio. Los datos analizados se obtuvieron al aplicar un cuestionario a 125 estudiantes de secundaria, para posteriormente realizar un análisis de contenido, tal cuestionario se presenta en el Anexo A. Al realizar el análisis de contenido de las respuestas obtenidas, fue posible hacer algunas inferencias, como por ejemplo; muchos estudiantes tienen dificultades para desarrollar un modelo explicativo acerca del funcionamiento de una estrella; pocos estudiantes dicen que las estrellas tienen un cierto tiempo de vida; algunos estudiantes imaginan que las estrellas tienen puntas; pocos

  17. Volkswagen gastará hasta $14.7 mil millones para transigir alegaciones de haber mentido en las pruebas de emisiones y haber engañado a los clientes de vehículos diesel de 2.0 litros

    EPA Pesticide Factsheets

    Comunicado de prensa de la EPA: Volkswagen gastará hasta $14.7 mil millones para transigir alegaciones de haber mentido en las pruebas de emisiones y haber engañado a los clientes de vehículos diesel de 2.0 litros

  18. University Students' Conceptions about the Moon Phases. (Spanish Title: Concepciones de Estudiantes Universitários sobre Las Fases de la Luna.) Concepções de Estudantes Universitários sobre as Fases da Lua

    NASA Astrophysics Data System (ADS)

    de Fátima Oliveira Saraiva, Maria; da Silveira, Fernando Lang; Steffani, Maria Helena

    2011-07-01

    In this article we describe the development of a multiple choice test about lunar phases and analyze the results of its application to ten groups of Physics students at the UFRGS. During the improvement of the test, we noticed that the percentage of right answers about some concepts increased significantly when associated with the reformulation of the question, emphasizing the importance of being careful to avoid incorrect answers generated by unclear questions, and not by ignorance on the matter. We confirm the results of other studies that show that students have great difficulty to relate the Moon's phase with its position in the sky at given time. On the other hand, our results suggest that, in general, students of Physics understand the phenomenon of lunar phases better than the average of university students. En estese artículo se describe la elaboración de una prueba de opción múltiple sobre las fases de la Luna y se analizan los resultados de su aplicación en diez grupos de estudiantes de Física de UFRGS. Durante el mejoramiento de la prueba observamos que el porcentaje de aciertos creció considerablemente cuando considerada una nueva redacción de la pregunta, destacando el cuidado que se debe tomar a fin de evitar respuestas incorrectas generadas por preguntas poco claras y no a causa de la ignorancia de los estudiantes sobre el tema. Confirmamos los resultados de otros estudios que las mayores dificultades de los alumnos sobre el tema fases de la Luna están en relacionar la fase de la Luna con su posición en el cielo en determinado momento. Por otra parte, nuestros resultados sugieren que, en general, los estudiantes de la Física comprenden mejor el fenómeno de las fases lunares que el promedio de los estudiantes universitarios. Neste artigo descrevemos a elaboração de um teste de múltipla escolha sobre as fases da Lua e analisamos os resultados de sua aplicação em dez grupos de estudantes de Física da UFRGS. Durante o aprimoramento do

  19. Application of molecular docking and ONIOM methods for the description of interactions between anti-quorum sensing active (AHL) analogues and the Pseudomonas aeruginosa LasR binding site.

    PubMed

    Ahumedo, Maicol; Drosos, Juan Carlos; Vivas-Reyes, Ricardo

    2014-05-01

    Molecular docking methods were applied to simulate the coupling of a set of nineteen acyl homoserine lactone analogs into the binding site of the transcriptional receptor LasR. The best pose of each ligand was explored and a qualitative analysis of the possible interactions present in the complex was performed. From the results of the protein-ligand complex analysis, it was found that residues Tyr-64 and Tyr-47 are involved in important interactions, which mainly determine the antagonistic activity of the AHL analogues considered for this study. The effect of different substituents on the aromatic ring, the common structure to all ligands, was also evaluated focusing on how the interaction with the two previously mentioned tyrosine residues was affected. Electrostatic potential map calculations based on the electron density and the van der Waals radii were performed on all ligands to graphically aid in the explanation of the variation of charge density on their structures when the substituent on the aromatic ring is changed through the elements of the halogen group series. A quantitative approach was also considered and for that purpose the ONIOM method was performed to estimate the energy change in the different ligand-receptor complex regions. Those energy values were tested for their relationship with the corresponding IC50 in order to establish if there is any correlation between energy changes in the selected regions and the biological activity. The results obtained using the two approaches may contribute to the field of quorum sensing active molecules; the docking analysis revealed the role of some binding site residues involved in the formation of a halogen bridge with ligands. These interactions have been demonstrated to be responsible for the interruption of the signal propagation needed for the quorum sensing circuit. Using the other approach, the structure-activity relationship (SAR) analysis, it was possible to establish which structural characteristics

  20. Hydrologic and geologic characteristics of the Yucca Mountain site relevant to the performance of a potential repository: Day 1, Las Vegas, Nevada to Pahrump, Nevada: Stop 6A. Keane Wonder Spring and regional groundwater flow in the Death Valley region

    USGS Publications Warehouse

    Steinkampf, W.C.

    2000-01-01

    Yucca Mountain, located ~100 mi northwest of Las Vegas, Nevada, has been designated by Congress as a site to be characterized for a potential mined geologic repository for high-level radioactive waste. This field trip will examine the regional geologic and hydrologic setting for Yucca Mountain, as well as specific results of the site characterization program, The first day focuses on the regional seeing with emphasis on current and paleo hydrology, which are both of critical concern for predicting future performance of a potential repository. Morning stops will be in southern Nevada and afternoon stops will be in Death Valley. The second day will be spent at Yucca Mountain. The filed trip will visit the underground testing sites in the "Exploratory Studies Facility" and the "Busted Butte Unsaturated Zone Transport Field Test" plus several surface-based testing sites. Much of the work at the site has concentrated on studies of the unsaturated zone, and element of the hydrologic system that historically has received little attention. Discussions during the second day will comprise selected topics of Yucca Mountain geology, mic hazard in the Yucca Mountain area. Evening discussions will address modeling of regional groundwater flow, the geology and hydrology of Yucca Mountain to the performance of a potential repository. Day 3 will examine the geologic framework and hydrology of the Pahute Mesa-Oasis Valley Groundwater Basin and then will continue to Reno via Hawthorne, Nevada and the Walker Lake area.

  1. Arbovirus investigations in Argentina, 1977-1980. III. Identification and characterization of viruses isolated, including new subtypes of western and Venezuelan equine encephalitis viruses and four new bunyaviruses (Las Maloyas, Resistencia, Barranqueras, and Antequera).

    PubMed

    Calisher, C H; Monath, T P; Mitchell, C J; Sabattini, M S; Cropp, C B; Kerschner, J; Hunt, A R; Lazuick, J S

    1985-09-01

    Forty viruses isolated from mosquitoes between 1977 and 1980 in Argentina have been identified and characterized. Nineteen strains of VEE virus, identical by neutralization (N) tests, were shown by hemagglutination-inhibition tests with anti-E2 glycoprotein sera to represent a new subtype VI of the VEE complex. RNA oligonucleotide fingerprints of this virus were distinct from subtype I viruses. The virus was not lethal for English short-haired guinea pigs, indicating that it is probably not equine-virulent. Three strains of a member of the WEE virus complex were shown to differ by N tests in 1 direction from prototype WEE virus. The new WEE subtype was also found to be distinct by RNA oligonucleotide mapping. Its vector relationships indicate that it is an enzootic virus, and it has not been associated with equine disease. A new member of the Anopheles A serogroup was identified, shown to be most closely related to Lukuni and Col An 57389 viruses, and given the name Las Maloyas virus. A strain of Para virus (Bunyaviridae, Bunyavirus) was identified. Six isolates, representing 3 new viruses morphologically resembling bunyaviruses are described; the names Antequera, Barranqueras, and Resistencia are proposed for these agents, which were all isolated from Culex (Melanoconion) delpontei in Chaco Province. No serologic relationships between these viruses and other bunyaviruses were found. Since they are antigenically interrelated, they form a new (Antequera) serogroup. Eight Gamboa serogroup viruses and 2 strains of St. Louis encephalitis virus were also identified.

  2. A Proposed Activity for a Meaningful Learning about the Moon Phases. (Breton Title: Uma Proposta de Atividade Para a Aprendizagem Significativa sobre as Fases da Lua.) Una Actividad Propuesta Para EL Aprendizaje Significativo Acerca de Las Fases de la Luna

    NASA Astrophysics Data System (ADS)

    Martins, Bruno Andrade; Langhi, Rodolfo

    2012-12-01

    ínua avaliação durante o processo, culmina com a elaboração de uma história em quadrinhos envolvendo as fases da Lua. Portanto, o objetivo deste trabalho é apresentar uma proposta de atividade didática diferenciada sustentada pelos princípios teóricos da aprendizagem significativa aplicada ao ensino das fases da Lua durante as aulas de Física no ensino médio. En este trabajo se presenta uno de los contenidos de la Astronomía y el evidente fracaso en la enseñanza del tema en la escuela secundaria, a pesar del hecho que los documentos oficiales apuntan para la necesidad de trabajar contenidos de Astronomía en este nivel. Entre los conceptos alternativos en Astronomía que los alumnos secundarios llevan consigo, aún después de terminados los estudios, destacamos aquí el fenómeno de las fases de la Luna. El desarrollo de diferentes estrategias en relación con los métodos tradicionales, dirigidas al proceso de enseñanza-aprendizaje en este tema fue considerado en este trabajo como uno de los resultados obtenidos a la luz de los referenciales del aprendizaje significativo, tal como fueron fundamentados por Ausubel. Según la propuesta que aquí se presenta, la participación activa de los estudiantes en la ejecución de una actividad experimental y otras actividades educativas destinadas a la evaluación continua durante el proceso culminó en la elaboración de una historieta respecto de las fases de la Luna. Por lo tanto, el objetivo de este trabajo es presentar una propuesta de actividad de enseñanza diferenciada con el apoyo de los principios teóricos del aprendizaje significativo aplicado a la enseñanza de las fases de la luna durante las clases de física del ciclo secundario.

  3. Brazil = Brasil. America = Las Americas [Series].

    ERIC Educational Resources Information Center

    Toro, Leonor; And Others

    Written for teachers to use with migrant children in elementary grades, this bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Brazil's history, geography, economy, and culture. Topics include Brazil's form of government; geographic regions; holidays; climate; people; music; carnaval celebration;…

  4. Las Vegas Area (ARMS-II)

    DTIC Science & Technology

    1963-07-10

    0-33 1 4~raI ŘF I -6 WS robe 0 . - o d io.s NV "j/" %%A68064 ana -1 / :IM P i . " r(" ----- I G Glass’n Ocerton8/~ . - donl ’<’> BOULD CAV YO Mea...8217,, \\ •’•’, .. /N 7’-.-... . ."p PEot I a’ ( 4 (4 ;\\Zinc "’. -l-- "% -- -""’, f r-, 4., .. •_.:• ...... ’ \\,, -. ’K 2-=5 -~I 5-8 ,..., Mi./5 S Mill

  5. America = Las Americas. Canada, United States, Mexico.

    ERIC Educational Resources Information Center

    Toro, Leonor; And Others

    Written for teachers to use with migrant children in elementary grades and to highlight the many Americas, three magazines provide historical and cultural background information on Canada, the United States, and Mexico and feature biographies of Black and Hispanic leaders. Each edition has a table of contents indicating the language--Spanish…

  6. Quantifying the time scale of elevated geomorphic response following wildfires using multi-temporal LiDAR data: An example from the Las Conchas fire, Jemez Mountains, New Mexico

    NASA Astrophysics Data System (ADS)

    Orem, Caitlin A.; Pelletier, Jon D.

    2015-03-01

    Sediment yields commonly increase following wildfires in mountainous landscapes. Quantifying the magnitude and duration of elevated sediment yields following wildfires is important for quantifying the relative importance of wildfire-affected versus non-wildfire-affected erosion in the long-term evolution of landscapes and for understanding the processes of post-wildfire erosion. In this study we use bi-annual terrestrial laser scanning (TLS) surveys conducted over a 2-yr period together with repeat airborne laser scanning (ALS) surveys conducted over a 1-yr period to estimate the dependence of sediment yield on time following the high-severity Las Conchas fire of 2011 within two small (approximately 1.3 km2) watersheds. The dependence of sediment yield on time since the wildfire was quantified using DEMs of Difference (DoDs) of the upland watersheds (to measure erosion) and of the adjacent piedmonts (to measure the deposition of eroded sediment). Over the 2-yr study period, sediment volume decreased linearly with time and sediment yield decreased exponentially with time in one watershed, while the other watershed showed a more complex relationship with time influenced by the specific sequence of rainstorms that impacted that watershed. Both watersheds had a recovery time of approximately 1 yr, suggesting that vegetation regrowth and the stabilization of incised valley bottoms were primarily responsible for the decline in sediment yield versus time following the wildfire. Multi-temporal DoDs of the piedmonts show how they responded to the delivery of elevated sediment yields from the upland watersheds, i.e. by (1) incision of the proximal portion of the piedmont, triggering distal deposition, (2) infilling of the incised channel and avulsion, and (3) incision of the distal portion, creating an incised channel connecting the proximal and distal ends of the piedmont. The dynamic nature of incision/aggradation and channel shifting on piedmonts following wildfires has

  7. The Pseudomonas aeruginosa quinolone signal molecule overcomes the cell density-dependency of the quorum sensing hierarchy, regulates rhl-dependent genes at the onset of stationary phase and can be produced in the absence of LasR.

    PubMed

    Diggle, Stephen P; Winzer, Klaus; Chhabra, Siri Ram; Worrall, Kathryn E; Cámara, Miguel; Williams, Paul

    2003-10-01

    In Pseudomonas aeruginosa, diverse exoproduct virulence determinants are regulated via N-acylhomoserine lactone-dependent quorum sensing. Here we show that 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) is also an integral component of the quorum sensing circuitry and is required for the production of rhl-dependent exoproducts at the onset of stationary phase. Analysis of spent P. aeruginosa culture supernatants revealed that PQS is produced at the end of exponential phase in the parent strain and in the late stationary phase of a lasR mutant. Mutants defective in both PQS production (pqsR-) and response (pqsE-) produced substantially reduced levels of exoproducts but retained wild-type N-butanoyl homoserine lactone (C4-HSL) levels. In the wild type, provision of exogenous PQS at the time of inoculation significantly increased PA-IL lectin, pyocyanin and elastase production during early stationary phase and promoted biofilm formation. Exogenous PQS but not PQS derivatives lacking the 3-hydroxy group overcame the cell density but not growth phase-dependent production of exoproducts. PQS also overcame the transcriptional and post-transcriptional repression of lecA (which codes for the PA-IL lectin) mediated via the negative regulators MvaT and RsmA respectively. Increased expression of lecA in the presence of exogenous PQS can be explained partially by increases in RhlR, RpoS and C4-HSL levels. A refined model for quorum sensing in P. aeruginosa is presented.

  8. Fluorescence spectra and elastic scattering characteristics of atmospheric aerosol in Las Cruces, New Mexico, USA: Variability of concentrations and possible constituents and sources of particles in various spectral clusters

    NASA Astrophysics Data System (ADS)

    Pinnick, R. G.; Fernandez, E.; Rosen, J. M.; Hill, S. C.; Wang, Y.; Pan, Y. L.

    2013-02-01

    The UV-excited laser-induced-fluorescence (UV-LIF) spectra of single atmospheric particles and the three-band integrating-nephelometer elastic scattering of atmospheric aerosol were measured during four approximately 24-h periods on May 2007 in Las Cruces, New Mexico, USA. Aerosol scattering measurements in the nephelometer red channel (50-nm band centered at 700-nm) ranged from around 3-10 times the molecular (Rayleigh) scattering background. On average 22.8% of particles with size greater than about 1 μm diameter have fluorescence above a preset fluorescence threshold. A hierarchical cluster analysis indicates that most of the single-particle UV-LIF spectra fall into about 10 categories (spectral clusters) as found previously at other geographic sites (Pinnick et al., 2004; Pan et al., 2007). The clusters include spectra characteristic of various humic/fulvic acids, humic-like-substances (HULIS), chemically aged terpenes, fungal spores, polycyclic aromatic hydrocarbons, bacteria, cellulose/pollens, and mixtures of various organic carbon compounds. By far the most populated cluster category is similar to those of chemically aged terpenes/humic-materials; on average this population comprises about 62% of fluorescent particles. Clusters with spectra similar to that of some HULIS aerosol contain on average 10.0% of particles; those characteristic of some fungal spores (or perhaps mixtures of aromatic organic compounds) 8.4% of particles; bacteria-like spectra 1.6% of particles; and cellulose/pollen-like spectra 0.8% of particles. Measurements of fluorescent particles over relatively short (24 min) periods reveal that the concentrations of particles in the most populated clusters are highly correlated, suggesting that the particles populating them derive from the same region; these particles might be composed of crustal material coated with secondary organic carbon. On the other hand, concentrations of particles having cellulose-like spectra are generally

  9. A preliminary evaluation of vertical separation between production intervals of coalbed-methane wells and water-supply wells in the Raton basin, Huerfano and Las Animas Counties, Colorado, 1999-2004

    USGS Publications Warehouse

    Watts, Kenneth R.

    2006-01-01

    The Raton Basin in southern Colorado and northern New Mexico is undergoing increased development of its coalbed-methane resources. Annual production of methane from coalbeds in the Raton Basin in Huerfano and Las Animas Counties, Colorado, increased from about 28,000,000 thousand cubic feet from 478 wells to about 80,000,000 thousand cubic feet from 1,543 wells, during 1999-2004. Annual ground-water withdrawals for coalbed-methane production increased from about 1.45 billion gallons from 480 wells to about 3.64 billion gallons from 1,568 wells, during 1999-2004. Where the coalbeds are deeply buried near the center of the Raton Basin, water pressure may be reduced as much as 250 to 300 pounds per square inch to produce the methane from the coalbeds, which is equivalent to a 577- to 692-foot lowering of water level. In 2001, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began an evaluation of the potential effects of coalbed- methane production on the availability and sustainability of ground-water resources. In 2003, there were an estimated 1,370 water-supply wells in the Raton Basin in Colorado, and about 90 percent of these water-supply wells were less than 450 feet deep. The tops of the production (perforated) interval of 90 percent of the coalbed-methane wells in the Raton Basin (for which data were available) are deeper than about 675 feet. The potential for interference of coalbed-methane wells with nearby water-supply wells likely is limited because in most areas their respective production intervals are separated by more than a hundred to a few thousand feet of rock. The estimated vertical separation between production intervals of coalbed-methane and water-supply wells is less than 100 feet in an area about 1 to 6 miles west and southwest of Trinidad Lake and a few other isolated areas. It is assumed that in areas with less than 100 feet of vertical separation, production by coalbed-methane wells has a greater

  10. Inmunoterapias para las adicciones a las drogas Immunotherapies for Drug Addictions

    PubMed Central

    Montoya, Iván D.

    2008-01-01

    Immunotherapies in the form of vaccines (active immunization) or monoclonal antibodies (passive immunization) appear safe and a promising treatment approaches for some substance-related disorders. The mechanism of action of the antibody therapy is by preventing the rapid entry of drugs of abuse into the central nervous system. In theory, immunotherapies could have several clinical applications. Monoclonal antibodies may be useful to treat drug overdoses and prevent the neurotoxic effects of drugs by blocking the access of drugs to the brain. Vaccines may help to prevent the development of addiction, initiate drug abstinence in those already addicted to drugs, or prevent drug use relapse by reducing the pharmacological effects and rewarding properties of the drugs of abuse on the brain. Passive immunization with monoclonal antibodies has been investigated for cocaine, methamphetamine, nicotine, and phencyclidine (PCP). Active immunization with vaccines has been studied for cocaine, heroin, methamphetamine, and nicotine. These immunotherapies seem promising therapeutic tools and are at different stages in their development before they can be approved by regulatory agencies for the treatment of substance-related disorders. The purpose of this article is to review the current immunotherapy approaches with emphasis on the risks and benefits for the treatment of these disorders. PMID:18551223

  11. Retrofitting Las Vegas. Implementing Energy Efficiency in Two Las Vegas Test Homes

    SciTech Connect

    Puttagunta, S.

    2013-04-01

    In 2009, the state of Nevada received nearly $40 million in Neighborhood Stabilization Funds from the Department of Housing and Urban Development to use to stabilize communities that have suffered from foreclosures and abandonment. In order to provide guidance to local officials and maximize how effectively this NSP funding is used in retrofitting homes, the CARB team provided design specifications, energy modeling, and technical support for the BARA team and its local partners—Better Building Performance, Nevada Energy Star Partners Green Alliance, and Home Free Nevada—for two retrofit test homes. One home demonstrated a modest retrofit and the other a deep energy retrofit. This report describes the retrofit packages, which were used as an educational experience for home performance professionals, building trades, remodelers, and the general public.

  12. Astronomy in High School: Using a Mini-Planetarium to Understand Details of the Apparent Movement of Stars. (Spanish Title: Astronomía en la Escuela Secundaria: Comprendiendo los Detalles del Movimiento Aparente de Las Estrellas con un Miniplanetario.) Astronomia no Ensino Médio: Compreendendo Detalhes do Movimento Aparente das Estrelas com um Miniplanetário

    NASA Astrophysics Data System (ADS)

    dos Santos Leão, Demetrius

    2013-07-01

    The aim of this article is to present part of the results obtained by the intervention made from the author's Master degree project, which consisted in the development of a set of Astronomy classes for first year of High School students from a private school in the "Distrito Federal", Brasilia, Brazil, making use of a didactical material called mini-planetarium (MP) as the main resource. Using Paulo Freire's contextualization and dialogicity ideas as a theoretical framework guided by these lessons, it was proposed to the students the assembly and application of that resource in a planetarium session. During the project, some subjects such as the apparent trajectory of stars through Brasilia's sky, the location of the cardinal points beginning from the Southern Cross constellation, the color of stars and the stars being seen from a particular place were emphasized. It was found that the students showed an improvement of their understanding about these subjects, as well as a significant excitement with the developed methodology. El objetivo de este trabajo es presentar algunos de los resultados obtenidos en el proyecto de la tesis de maestría del autor, que incluyó el desarrollo de algunas clases de Astronomía, con estudiantes del primer año del bachillerato de una escuela privada del Distrito Federal (Brasilia, Brasil), utilizando como materia prima didáctica el recurso llamado miniplanetario (MP). Utilizando como base teórica orientadora de esas clases las ideas de contextualización y dialógica de Paulo Freire, fue propuesto a los estudiantes el montaje y la utilización de este recurso en una función de planetario. Durante el proyecto, se enfatizaron asuntos tales como la trayectoria aparente de las estrellas del cielo de Brasilia, la ubicación de los puntos cardinales a partir de la constelación de la Cruz del Sur, los colores de las estrellas y las estrellas vistas desde una localidad determinada. Se constató que los estudiantes mostraron una mejora

  13. Plan para las Escuelas "Sabatinas" (Plan for the "Saturday Schools").

    ERIC Educational Resources Information Center

    Campos, Miguel A.; Williams, David R.

    The Escuelas "Sabatinas" (Saturday Schools) program in Costa Rica will be for adults 18 and over who wish to obtain a primary school diploma on the basis of maturity, and who have enough general knowledge, intelligence, and maturity to undertake independent study supplemented by formal instruction. The course will run two years, 36 weeks…

  14. MLAS and LAS: Project Comparison of Lessons Learned

    NASA Technical Reports Server (NTRS)

    Dittemore, Gary

    2011-01-01

    The development of new and safer manned space vehicles is a top priority at NASA. Recently two different approaches of how to accomplish this mission of keeping astronauts safe was successfully demonstrated. With work already underway on an Apollo-like launch abort system for the Orion Crew Exploration Vehicle (CEV), an alternative design concept named the Max Launch Abort System, or MLAS, was developed as a parallel effort. The Orion system, managed by the Constellation office, is based on the design of a single solid launch abort motor in a tower positioned above the capsule. The MLAS design takes a different approach placing the solid launch abort motor underneath the capsule. This effort was led by the NASA Engineering and Safety Center (NESC). Both escape systems were designed with the Ares I Rocket as the launch vehicle and had the same primary requirement to safely propel a crew module away from any emergency event either on the launch pad or during accent. Beyond these two parameters, there was little else in common between the two projects, except that they both concluded in successful launches that will further promote the development of crew launch abort systems. This presentation will compare both projects from the standpoint of technical requirements; program management and flight test objectives and highlight the synergistic lessons learned by two engineers who worked on each program.

  15. The New American Home: Las Vegas, Nevada -- 2003

    SciTech Connect

    2002-12-01

    The New American Home is an annual showcase project designed by committee and co-sponsored by the National Association of Home Builder’s National Council of the Housing Industry (NCHI) and Builder Magazine. This year it was a building project for Amland D

  16. University of Nevada Las Vegas LED Display Engineering

    SciTech Connect

    2010-08-31

    The primary objective of this part of the project is to develop and implement a method that compensates for the inefficiency of the green LED. The proposed engineering solution which will be the backbone of this project will be to use RGBW combination in every pixel to save energy. Two different RGBW geometrical pixel configurations will be implemented and compared against traditional LED configurations. These configurations will be analyzed for energy efficiency while keeping the quality of the display the same. Cost of the addition of white LEDs to displays along with energy cost savings will be presented and analyzed.

  17. La Chispa De Las Honduranos: Imperialism and Human Experience

    ERIC Educational Resources Information Center

    Thornton, Rebecca Mercado

    2012-01-01

    This article explores a student's expectations and the lived realities of a two-week service learning trip to Honduras. Originally, her expectations were critical and cynical. But through a series of journal entries she made during the program, she shows how her expectations were transformed by the actual experience and how she achieved her own…

  18. Como Promover el Exito de las Ninas y las Minorias en las Ciencias y en las Matematicas. Para Padres/sobre Padres (How To Promote the Science and Mathematics Achievement of Females and Minorities. For Parents/about Parents).

    ERIC Educational Resources Information Center

    Schwartz, Wendy

    Some minority and female students traditionally have not been given the help they need to enroll and succeed in mathematics and science classes. Now, however, various approaches are available to give these students the extra attention they need. Parents can help children develop an interest in science and mathematics by: (1) identifying role…

  19. Politica de las Construcciones Escolares (Policy for School Construction).

    ERIC Educational Resources Information Center

    Storni, Adolfo Enrique, Ed.; And Others

    This document establishes the policy for school construction programs and projects to be conducted in Argentina. The first part establishes the bases for construction and defines the policy and its objectives. The second part discusses school construction in view of educational reform and planning and considers analysis of current systems,…

  20. Las uniones conjuntivas en espanol (Conjunctive Correspondences in Spanish)

    ERIC Educational Resources Information Center

    Perez Botero, Luis

    1977-01-01

    This study of the medieval Spanish concept of order examines uses made of the word "y" ("and") in Spanish medieval writing to join words and phrases connoting social, natural and human order. (Text is in Spanish.) (CHK)