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Sample records for laguna verde basado

  1. The radiological emergency plan to the Laguna Verde Nuclear Power Plant

    SciTech Connect

    Villard, M.M.; Magana, R.O. )

    1992-01-01

    In this paper, it is described the main characteristics of the area surrounding the Laguna Verde Nuclear Power Plant, in terms of population, main economic activities, housing and infrastructure. Based on those factors, the most important features of the Radiological Emergency Plan are described.

  2. 15,000-yr pollen record of vegetation change in the high altitude tropical Andes at Laguna Verde Alta, Venezuela

    NASA Astrophysics Data System (ADS)

    Rull, Valentí; Abbott, Mark B.; Polissar, Pratigya J.; Wolfe, Alexander P.; Bezada, Maximiliano; Bradley, Raymond S.

    2005-11-01

    Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced ˜15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the superpáramo. Although this community persisted until ˜6000 cal yr B.P., it began to decline somewhat earlier, in synchrony with cooling following the Holocene thermal maximum of the Northern Hemisphere. At this time, the pioneer assemblage was replaced by a low-diversity superpáramo community that became established ˜9000 cal yr B.P. This replacement coincides with regional declines in temperature and/or available moisture. Modern, more diverse superpáramo assemblages were not established until ˜4600 cal yr B.P., and were accompanied by a dramatic decline in Alnus, probably the result of factors associated with climate, humans, or both. Pollen influx from upper Andean forests is remarkably higher than expected during the Late Glacial and early to middle Holocene, especially between 14,000 and 12,600 cal yr B.P., when unparalleled high values are recorded. We propose that intensification of upslope orographic winds transported lower elevation forest pollen to the superpáramo, causing the apparent increase in tree pollen at high altitude. The association between increased forest pollen and summer insolation at this time suggests a causal link; however, further work is needed to clarify this relationship.

  3. Estimate of Radiation-Induced Steel Embrittlement in the BWR Core Shroud and Vessel Wall from Reactor-Grade MOX/UOX Fuel for the Nuclear Power Plant at Laguna Verde, Veracruz, Mexico

    SciTech Connect

    Vickers, Lisa R.

    2002-07-01

    The government of Mexico has expressed interest to utilize the Laguna Verde boiling water reactor (BWR) nuclear power plant for the disposition of reprocessed spent uranium oxide (UOX) fuel in the form of reactor-grade mixed oxide (MOX) fuel. MOX fuel would replace spent UOX fuel as a fraction in the core from 18 - 30% depending on the fuel loading cycle. MOX fuel is expected to increase the neutron fluence, flux, fuel centerline temperature, reactor core pressure, and yield higher energy neutrons. There is concern that a core with a fraction of MOX fuel (i.e., increased {sup 239}Pu wt%) would increase the radiation-induced steel embrittlement within the core shroud and vessel wall as compared to only conventional, enriched UOX fuel in the core. The evaluation of radiation-induced steel embrittlement within the core shroud and vessel wall is a concern because of the potentially adverse affect to personnel and public safety, environment, and operating life of the reactor. The primary conclusion of this research was that the addition of the maximum fraction of 1/3 MOX fuel to the LV1 BWR core did significantly accelerate the radiation-induced steel embrittlement such that without mitigation of steel embrittlement by periodic thermal annealing or reduction in operating parameters such as, neutron fluence, core temperature and pressure, it posed a potentially adverse affect to the personnel and public safety, environment, and operating life of the reactor. (author)

  4. Cape Verde

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This Mars Exploration Rover Opportunity Pancam 'super resolution' mosaic of the approximately 6 m (20 foot) high cliff face of the Cape Verde promontory was taken by the rover from inside Victoria Crater, during the rover's descent into Duck Bay. Super-resolution is an imaging technique which utilizes information from multiple pictures of the same target in order to generate an image with a higher resolution than any of the individual images. Cape Verde is a geologically rich outcrop and is teaching scientists about how rocks at Victoria crater were modified since they were deposited long ago. This image complements super resolution mosaics obtained at Cape St. Mary and Cape St. Vincent and is consistent with the hypothesis that Victoria crater is located in the middle of what used to be an ancient sand dune field. Many rover team scientists are hoping to be able to eventually drive the rover closer to these layered rocks in the hopes of measuring their chemistry and mineralogy.

    This is a Mars Exploration Rover Opportunity Panoramic Camera image mosaic acquired on sols 1342 and 1356 (November 2 and 17, 2007), and was constructed from a mathematical combination of 64 different blue filter (480 nm) images.

  5. The Pueblo of Laguna.

    ERIC Educational Resources Information Center

    Lockart, Barbetta L.

    Proximity to urban areas, a high employment rate, development of natural resources and high academic achievement are all serving to bring Laguna Pueblo to a period of rapid change on the reservation. While working to realize its potential in the areas of natural resources, commercialism and education, the Pueblo must also confront the problems of…

  6. Laguna Symbolic Geography and Silko's "Ceremony."

    ERIC Educational Resources Information Center

    Swan, Edith

    1988-01-01

    Outlines the Laguna (Pueblo) symbolic geography or world view as it is woven into Leslie Silko's novel "Ceremony." Explains the protagonist's spiritual journey toward health and harmony in terms of symbols and beliefs in Laguna mythology. Contains 21 references. (SV)

  7. Mesa Verde Archaeoastronomy

    NASA Astrophysics Data System (ADS)

    Munson, Gregory E.

    Mesa Verde archaeoastronomy has been studied for over 100 years through academic research. Investigators have excavated, stabilized, and documented the major dwellings in Mesa Verde National Park. Evidence for astronomical orientation and alignment was found in Cliff Palace and Sun Temple. The level of documentation increased with each new research project. With good documentation practices, together, the research has shown that the cultures of the Mesa Verde were advanced in their social organization and use of astronomy. Consultation with Native American tribal leaders will add significant background to the depth of knowledge that their ancestors possessed.

  8. The LAGUNA-LBNO Project

    NASA Astrophysics Data System (ADS)

    Avanzini, Margherita Buizza

    LAGUNA-LBNO is a Design Study funded by the European Commission to develop the design of a large and deep underground neutrino observatory; its physics program involves the study of neutrino oscillations at long baselines, the investigation of the Grand Unification of elementary forces and the detection of neutrinos from astrophysical sources. Building on the successful format and on the findings of the previous LAGUNA Design Study, LAGUNA-LBNO is more focused and is specifically considering Long Baseline Neutrino Oscillations (LBNO) with neutrino beams from CERN. Two sites, Fréjus (in France at 130 km) and Pyhäsalmi (in Finland at 2300 km), are being considered. Three different detector technologies are being studied: Water Cherenkov, Liquid Scintillator and Liquid Argon. Recently the LAGUNA-LBNO consortium has submitted an Expression of Interest for a very long baseline neutrino experiment, selecting as a first priority the option of a Liquid Argon detector at Pyhäsalmi. Detailed potential studies have been curried out for the determination of the neutrino Mass Hierarchy and the discovery of the CP-violation, using a conventional neutrino beam from the CERN SPS with a power of 750 kW.

  9. Panorama from 'Cape Verde'

    NASA Technical Reports Server (NTRS)

    2007-01-01

    NASA's Mars Exploration Rover Opportunity captured this vista of 'Victoria Crater' from the viewpoint of 'Cape Verde,' one of the promontories that are part of the scalloped rim of the crater. Opportunity drove onto Cape Verde shortly after arriving at the rim of Victoria in September 2006. The view combines hundreds of exposures taken by the rover's panoramic camera (Pancam). The camera began taking the component images during Opportunity's 970th Martian day, or sol, on Mars (Oct. 16, 2006). Work on the panorama continued through the solar conjunction period, when Mars was nearly behind the sun from Earth's perspective and communications were minimized. Acquisition of images for this panorama was completed on Opportunity's 991st sol (Nov. 7, 2006).

    The top of Cape Verde is in the immediate foreground at the center of the image. To the left and right are two of the more gradually sloped bays that alternate with the cliff-faced capes or promontories around the rim of the crater. 'Duck Bay,' where Opportunity first reached the rim, is to the right. Beyond Duck Bay counterclockwise around the rim, the next promontory is 'Cabo Frio,' about 150 meters (500 feet) from the rover. On the left side of the panorama is 'Cape St. Mary,' the next promontory clockwise from Cape Verde and about 40 meters (130 feet) from the rover. The vantage point atop Cape Verde offered a good view of the rock layers in the cliff face of Cape St. Mary, which is about 15 meters or 50 feet tall. By about two weeks after the Pancam finished collecting the images for this panorama, Opportunity had driven to Cape St. Mary and was photographing Cape Verde's rock layers.

    The far side of the crater lies about 800 meters (half a mile) away, toward the southeast.

    This approximately true-color view combines images taken through three of the Pancam's filters, admitting light with wavelengths centered at 750 nanometers (near infrared), 530 nanometers (green) and 430 nanometers (violet).

  10. Variables Affecting Change at Laguna Elementary School.

    ERIC Educational Resources Information Center

    Lockart, Barbetta L.

    After nearly 14 years of non-Indian administration, Laguna Elementary School (LES) has acquired a principal and a teacher supervisor who are not merely Indian, but of the Laguna Tribe itself, making LES the only school in the Southern Pueblos Agency with Tribal members as administrators. At first glance the situation is ideal, but there are…

  11. VERDE Analytic Modules

    Energy Science and Technology Software Center (ESTSC)

    2008-01-15

    The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates servedmore » within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.« less

  12. VERDE Analytic Modules

    SciTech Connect

    2008-01-15

    The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates served within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.

  13. Palo Verde College Facts, 2001.

    ERIC Educational Resources Information Center

    Palo Verde Coll., Blythe, CA.

    This is a 2001 report on Palo Verde College (PVC) (California) student demographics, enrollment status, citizenship, educational goals, and academic persistence. Student data were collected and analyzed to meet accrediting standards, improve institutional effectiveness, and fulfill the local district's mission. The report discusses enrollment…

  14. Santa Fe Indian Camp, House 21, Richmond, California: Persistence of Identity among Laguna Pueblo Railroad Laborers, 1945-1982.

    ERIC Educational Resources Information Center

    Peters, Kurt

    1995-01-01

    In 1880 the Laguna people and the predecessor of the Atchison, Topeka, and Santa Fe Railroad reached an agreement giving the railroad unhindered right-of-way through Laguna lands in exchange for Laguna employment "forever." Discusses the Laguna-railroad relationship through 1982, Laguna labor camps in California, and the persistence of Laguna…

  15. Cape Verde in False Color

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A promontory nicknamed 'Cape Verde' can be seen jutting out from the walls of Victoria Crater in this false-color picture taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity. The rover took this picture on martian day, or sol, 1329 (Oct. 20, 2007), more than a month after it began descending down the crater walls -- and just 9 sols shy of its second Martian birthday on sol 1338 (Oct. 29, 2007). Opportunity landed on the Red Planet on Jan. 25, 2004. That's nearly four years ago on Earth, but only two on Mars because Mars takes longer to travel around the sun than Earth. One Martian year equals 687 Earth days.

    This view was taken using three panoramic-camera filters, admitting light with wavelengths centered at 750 nanometers (near infrared), 530 nanometers (green) and 430 nanometers (violet).

  16. Visualizing Energy Resources Dynamically on Earth (VERDE)

    Energy Science and Technology Software Center (ESTSC)

    2009-06-01

    VERDE is a software service that ingests data on real-time eneryg grid status and analyzes the data with models and algorithms presenting the output in a form that can be visualized by client spatio-temporal browsers

  17. VERDE2.5BetaVersion

    Energy Science and Technology Software Center (ESTSC)

    2002-07-31

    The Verde code verifies the correctness of a finite element mesh stored in the Exodusll file format. Verde calculates multiple quality metrics for each individual element, verifies local and global connectivity, analyzes interfaces between element blocks, predicts the probably topology of the mesh, and prints out any problems discovered. An optional graphics file contains graphics information about any problem elements/regions in the mesh.

  18. Limnology of Laguna Tortuguero, Puerto Rico

    USGS Publications Warehouse

    Quinones-Marquez, Ferdinand; Fuste, Luis A.

    1978-01-01

    The principal chemical, physical and biological characteristics, and the hydrology of Laguna Tortuguero, Puerto Rico, were studied from 1974-75. The lagoon, with an area of 2.24 square kilometers and a volume of about 2.68 million cubic meters, contains about 5 percent of seawater. Drainage through a canal on the north side averages 0.64 cubic meters per second per day, flushing the lagoon about 7.5 times per year. Chloride and sodium are the principal ions in the water, ranging from 300 to 700 mg/liter and 150 to 400 mg/liter, respectively. Among the nutrients, nitrogen averages about 1.7 mg/liter, exceeding phosphorus in a weight ratio of 170:1. About 10 percent of the nitrogen and 40 percent of the phosphorus entering the lagoon is retained. The bottom sediments, with a volume of about 4.5 million cubic meters, average 0.8 and 0.014 percent nitrogen and phosphorus, respectively. (Woodard-USGS)

  19. 2. AERIAL VIEW OF BRIDGE, LOOKING SOUTHEAST. THE VERDE RIVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. AERIAL VIEW OF BRIDGE, LOOKING SOUTHEAST. THE VERDE RIVER FLOWS FROM TOP TO BOTTOM. NOTE THE 'Z' CONFIGURATION OF THE RIVER. FOREST SERVICE ROUTE 269 IS SEEN IN THE LOWER LEFT CORNER. March 1987. - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  20. Hydrology of Laguna Joyuda, Puerto Rico

    USGS Publications Warehouse

    Santiago-Rivera, Luis; Quinones-Aponte, Vicente

    1995-01-01

    A study was conducted by the U.S. Geological Survey to define the hydraulic and hydrologic characteristics of the Laguna Joyuda system (in southwestern Puerto Rico) and to determine the water budget of the lagoon. This shallow-water lagoon is connected to the sea by a single canal. Rainfall and evaporation, surface-water, groundwater, and tidal-flow data were collected from December 1, 1985, to April 30, 1988. A conceptual hydrologic model of the lagoon was developed and discharge measurements and modeling were undertaken to quantify the different flow components. The water balance during the 29-month study period was determined by measuring and estimating the different hydrologic components: 4.14 million cubic meters rainfall; 5.38 million cubic meters evaporation; 1.1 8 million cubic meters surface water; and 0.34 million cubic meters ground water. A total of 18.9 million cubic meters ebb flow (tidal outflow) was discharged from the lagoon and 14.4 million cubic meters flood flow (tidal inflow) entered through the canal during the study. Seawater inflow accounted for 71 percent of the water into the lagoon. The storage volume of the lagoon was about 1.55 million cubic meters. The lagoon's hydrologic-budget residual was 4.22 million cubic meters, whereas the sum of the estimated errors for the different hydrologic components amounted to 4.51 million cubic meters. Average flushing rate for the lagoon was estimated at 72 days. During the study, the specific conductance of the lagoon water ranged from 32,000 to 52,000 microsiemens per centimeter at 25 degrees Celsius, whereas the specific conductance of local seawater is about 45,000 to 55,000 microsiemens.

  1. The Optometry Program at Universidad Autonoma de la Laguna, Mexico.

    ERIC Educational Resources Information Center

    Gonzalez, Agustin L.

    1995-01-01

    A description of the optometry program at the Universidad Autonoma de la Laguna (Mexico) provides information on the composition of the faculty, design of the five-year program as compared with the traditional four-year program, curriculum content, clinical education, visiting lecturer program, and certification of graduates. (MSE)

  2. Shallow Landslide Assessment using SINMAP in Laguna, Philippines

    NASA Astrophysics Data System (ADS)

    Bonus, A. A. B.; Rabonza, M. L.; Alemania, M. K. B.; Alejandrino, I. K.; Ybanez, R. L.; Lagmay, A. M. A.

    2014-12-01

    Due to the tectonic environment and tropical climate in the Philippines, both rain-induced and seismic-induced landslides are common in the country. Numerous hazard mapping activities are regularly conducted by both academic and government institutions using various tools and software. One such software is Stability Index Mapping (SINMAP), a terrain stability mapping tool applied to shallow translational landslide phenomena controlled by shallow groundwater flow convergence. SINMAP modelling combines a slope stability model with a steady-state hydrology model to delineate areas prone to shallow landslides. DOST- Project NOAH, one of the hazard-mapping initiatives of the government, aims to map all landslide hazard in the Philippines using both computer models as well as validating ground data. Laguna, located in the island of Luzon, is one such area where mapping and modelling is conducted. SINMAP modelling of the Laguna area was run with a 5-meter Interferomteric Synthetic Aperture Radar (IFSAR) derived digital terrain model (DTM). Topographic, soil-strength and physical hydrologic parameters, which include cohesion, angle of friction, bulk density and hydraulic conductivity, were assigned to each pixel of a given DTM grid to compute for the corresponding factor of safety. The landslide hazard map generated using SINMAP shows 2% of the total land area is highly susceptible in Santa Mara, Famy, Siniloan, Pangil, Pakil and Los Baἦos Laguna and 10% is moderately susceptible in the eastern parts of Laguna. The data derived from the model is consistent with both ground validation surveys as well as landslide inventories derived from high resolution satellite imagery from 2003 to 2013. With these combined computer and on-the-ground data, it is useful in identifying no-build zone areas and in monitoring activities of the local government units and other agencies concerned. This provides a reasonable delineation of hazard zones for shallow landslide susceptible areas of

  3. Panorama from 'Cape Verde' (False Color)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    NASA's Mars Exploration Rover Opportunity captured this vista of 'Victoria Crater' from the viewpoint of 'Cape Verde,' one of the promontories that are part of the scalloped rim of the crater. Opportunity drove onto Cape Verde shortly after arriving at the rim of Victoria in September 2006. The view combines hundreds of exposures taken by the rover's panoramic camera (Pancam). The camera began taking the component images during Opportunity's 970th Martian day, or sol, on Mars (Oct. 16, 2006). Work on the panorama continued through the solar conjunction period, when Mars was nearly behind the sun from Earth's perspective and communications were minimized. Acquisition of images for this panorama was completed on Opportunity's 991st sol (Nov. 7, 2006).

    The top of Cape Verde is in the immediate foreground at the center of the image. To the left and right are two of the more gradually sloped bays that alternate with the cliff-faced capes or promontories around the rim of the crater. 'Duck Bay,' where Opportunity first reached the rim, is to the right. Beyond Duck Bay counterclockwise around the rim, the next promontory is 'Cabo Frio,' about 150 meters (500 feet) from the rover. On the left side of the panorama is 'Cape St. Mary,' the next promontory clockwise from Cape Verde and about 40 meters (130 feet) from the rover. The vantage point atop Cape Verde offered a good view of the rock layers in the cliff face of Cape St. Mary, which is about 15 meters or 50 feet tall. By about two weeks after the Pancam finished collecting the images for this panorama, Opportunity had driven to Cape St. Mary and was photographing Cape Verde's rock layers.

    The far side of the crater lies about 800 meters (half a mile) away, toward the southeast.

    This view combines images taken through three of the Pancam's filters, admitting light with wavelengths centered at 750 nanometers (near infrared), 530 nanometers (green) and 430 nanometers (violet). It is presented in false

  4. 1. AERIAL VIEW OF BRIDGE, LOOKING NORTHWEST. VERDE RIVER FLOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW OF BRIDGE, LOOKING NORTHWEST. VERDE RIVER FLOWS FROM RIGHT TO LEFT. WHITE BUILDING AT UPPER CENTER IS BARN FORMERLY USED BY SHEEPHERDERS. THE SHEEP SHEARING CORRAL FLOOR SLAB IS AT LEFT OF BARN ACROSS THE ROAD. REMAINS OF OTHER BUILDINGS, INCLUDING A BUNKHOUSE, ARE SEEN BELOW AND TO THE RIGHT OF THE BARN. March 1987. - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  5. Revisiting the 23 February 1892 Laguna Salada earthquake

    USGS Publications Warehouse

    Hough, S.E.; Elliot, A.

    2004-01-01

    According to some compilations, the Laguna Salada, Baja California, earthquake of 23 February 1892 ranks among the largest earthquakes in California and Baja California in historic times. Although surface rupture was not documented at the time of the earthquake, recent geologic investigations have identified and mapped a rupture on the Laguna Salada fault that can be associated with high probability with the 1892 event (Mueller and Rockwell, 1995). The only intensity-based magnitude estimate for the earthquake, M 7.8, was made by Strand (1980) based on an interpretation of macroseismic effects and a comparison of isoseismal areas with those from instrumentally recorded earthquakes. In this study we reinterpret original accounts of the Laguna Salada earthquake. We assign modified Mercalli intensity (MMI) values in keeping with current practice, focusing on objective descriptions of damage rather than subjective human response and not assigning MMI values to effects that are now known to be poor indicators of shaking level, such as liquefaction and rockfalls. The reinterpreted isoseismal contours and the estimated magnitude are both significantly smaller than those obtained earlier. Using the method of Bakun and Wentworth (1997) we obtain a magnitude estimate of M 7.2 and an optimal epicenter less than 15 km from the center of the mapped Laguna Salada rupture. The isoseismal contours are elongated toward the northwest, which is qualitatively consistent with a directivity effect, assuming that the fault ruptured from southeast to northwest. We suggest that the elongation may also thus reflect wave propagation effects, with more efficient propagation of crustal surface (Lg) waves in the direction of the overall regional tectonic fabric.

  6. Strain accumulation along the Laguna Salada fault, Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Savage, J. C.; Lisowski, M.; King, N. E.; Gross, W. K.

    1994-09-01

    Strain accumulation observed over the 1978-1991 interval in a 30 x 100 km aperture trilateration network spanning the Laguna Salada fault is described by the principal strain rates 0.101 +/- 0.012 microstrain/yr N80 deg E +/- 2 deg and -0.021 +/- 0.012 microstrain/yr N 10 deg W +/- 2 deg, extension reckoned coseismic effects of the nearby 1979 Imperial Valley (M = 6.5), 1980 Vistoria (Baja California) (M = 6.4), 1987 Superstition Hills (M = 6.5), and 1987 Elmore Ranch (M = 5.9) earthquakes. The observed strain rates indicate extension at a rate of about 0.08 microstrain/yr perpendicular to the trend (N 35 deg W) of the Salton trough as well as a right-lateral tensor shear strain rate 0.05 microstrain/yr across it. The extension perpendicular to the trough is observed neither farther north near the Salton Sea nor farther south across the Gulf of California. However, Holocene slip on the Laguna Salada fault, about equal parts right-lateral and normal slip, is consistent with the observed strain accumulation. A simple dislocation model intended to explain the observed strain accumulation as a product of slip at depth on the Laguna Salada Fault would require that the fault be listric.

  7. 36 CFR 7.39 - Mesa Verde National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Mesa Verde National Park. 7.39 Section 7.39 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.39 Mesa Verde National Park. (a) Visiting...

  8. 36 CFR 7.39 - Mesa Verde National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Mesa Verde National Park. 7.39 Section 7.39 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.39 Mesa Verde National Park. (a) Visiting...

  9. 36 CFR 7.39 - Mesa Verde National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Mesa Verde National Park. 7.39 Section 7.39 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.39 Mesa Verde National Park. (a) Visiting...

  10. 36 CFR 7.39 - Mesa Verde National Park.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Mesa Verde National Park. 7.39 Section 7.39 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.39 Mesa Verde National Park. (a) Visiting...

  11. 36 CFR 7.39 - Mesa Verde National Park.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Mesa Verde National Park. 7.39 Section 7.39 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.39 Mesa Verde National Park. (a) Visiting...

  12. Possibilities For The LAGUNA Projects At The Frejus Site

    SciTech Connect

    Mosca, Luigi

    2010-11-24

    The present laboratory (LSM) at the Frejus site and the project of a first extension of it, mainly aimed at the next generation of dark matter and double beta decay experiments, are briefly reviewed. Then the main characteristics of the LAGUNA cooperation and Design Study network are summarized. Seven underground sites in Europe are considered in LAGUNA and are under study as candidates for the installation of Megaton scale detectors using three different techniques: a liquid Argon TPC (GLACIER), a liquid scintillator detector (LENA) and a Water Cerenkov (MEMPHYS), all mainly aimed at investigation of proton decay and properties of neutrinos from SuperNovae and other astrophysical sources as well as from accelerators (Super-beams and/or Beta-beams from CERN). One of the seven sites is located at Frejus, near the present LSM laboratory, and the results of its feasibility study are presented and discussed. Then the physics potential of a MEMPHYS detector installed in this site are emphasized both for non-accelerator and for neutrino beam based configurations. The MEMPHYNO prototype with its R and D programme is presented. Finally a possible schedule is sketched.

  13. Layers of 'Cape Verde' in 'Victoria Crater'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This view of Victoria crater is looking north from 'Duck Bay' towards the dramatic promontory called 'Cape Verde.' The dramatic cliff of layered rocks is about 50 meters (about 165 feet) away from the rover and is about 6 meters (about 20 feet) tall. The taller promontory beyond that is about 100 meters (about 325 feet) away, and the vista beyond that extends away for more than 400 meters (about 1300 feet) into the distance. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  14. Prioritizing species conservation: does the Cape Verde kite exist?

    PubMed

    Johnson, Jeff A; Watson, Richard T; Mindell, David P

    2005-07-01

    The Cape Verde kite (Milvus milvus fasciicauda) is considered to be one of the rarest birds of prey in the world and at significant risk of extinction. For this reason there is great interest in both the taxonomic and the population status of this group. To help resolve its taxonomic status, we provide phylogenetic analyses based on three mitochondrial genes for a sampling of kites in the genus Milvus, including a broad geographical sampling of black kites (Milvus migrans), red kites (Milvus milvus), Cape Verde kite museum specimens collected between 1897 and 1924, and five kites trapped on the Cape Verde Islands during August 2002. We found that the historical Cape Verde kites, including the type specimen, were non-monophyletic and scattered within a larger red kite clade. The recently trapped kites from the Cape Verde Islands were all phylogenetically diagnosed as black kites. Our findings suggest that the traditional Cape Verde kite is not a distinctive evolutionary unit, and the case for species status, as recently suggested by others, is not supported. We do find support for recognition of at least one clade of yellow-billed kites, traditionally considered as a black kite subspecies, as a distinctive phylogenetic species. PMID:16006325

  15. Sampling the Cape Verde Mantle Plume: Evolution of Santo Antão, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Holm, P. M.; Wilson, J. R.; Christensen, B. P.; Hansen, L.; Hansen, S. L.; Hein, K. M.; Mortensen, A. K.; Pedersen, R.; Plesner, S.; Runge, M. K.

    2003-12-01

    The 7.5 - 0.1 Ma old volcanics of the northwesternmost Cape Verde Island of Santo Antão show a change from early incompatible element enriched basanite-phonolite series to more enriched nephelinite/melilite nephelinite-phonolite series volcanics all of HIMU OIB type. Mantle melts were derived by 1-4 % melting and had around 12 wt.% MgO. Olivine Fo88-91 is found in many primitive volcanics. Incompatible element modelling shows that the geochemical change of the composition of the primary magmas requires source enrichment by silicate melts of mainly two compositional types. One of these is MORB. Isotopically the > 2 Ma Old Volcanics group can largely be explained by mixing of two components both with relatively radiogenic Sr and unradiogenic Nd of which one is a young HIMU type source (Δ 8/4 ˜ 0 and Δ 7/4 ˜ -5). The period 2 - 0.7 Ma saw two component mixing of two other end members of which one is a young HIMU source with less radiogenic Sr, more radiogenic Nd, Δ 8/4 ˜ -38 and Δ 7/4 ˜ -5, which isotopically is identical to an end member of carbonatites from the neighbouring island of São Vicente and the southern island Santiago. The youngest volcanics show stronger source enrichment, the most silica undersaturated magmas and an old HIMU-type component (Δ 7/4 > 2). The characteristic EM1-type enrichment of the southern Cape Verde Island is not detected on Santo Antão. We argue that the main components of Santo Antão volcanism are plume derived and reflect vertical variation in composition of rising plume material. The inter island variation of the Cape Verdes may reflect a lateral variation of the plume or lithosphere derived components in the southern island volcanics

  16. Magnetostratigraphy of Cape Verde Islands Volcanics

    NASA Astrophysics Data System (ADS)

    Knudsen, M. F.; Abrahamsen, N.

    2003-12-01

    During three field campaigns on the Cape Verde Islands (15N, 24W) in 1998, 2000, and 2003 paleomagnetic collections of several volcanic profiles from 5 of the 9 populated islands of the Cape Verde Archipelago were made. A summary of the paleomagnetic results obtained for some of the islands will be given in the presentation. On the island of Santo Antao paleomagnetic and magnetostratigraphic results from four lava sequences have been obtained: The Tarrafal, Agua Nova, Cha de Morte and Escabecada profiles. From the Tarrafal and Agua Nova profiles, 63 and 43 lava flows were investigated, respectively. Absolute Ar/Ar-ages indicate that the two profiles mainly correlate to the Brunhes Chron, which is in accordance with the normal polarity displayed by the majority of the flows. Some individual lava flows as well as flow sequences with virtual geomagnetic poles deviating more than 45 degrees from the geographic pole are interpreted as geomagnetic excursions, the number of which seem to be increasing these years. The most noticeable observations are the indications of Brunhes-aged reverse-polarity flows found within the Tarrafal and Agua Nova profiles. From the Cha de Morte and Escabecada lava sequences 21 and 24 lava flows were sampled, respectively. The uppermost flow in the Cha de Morte profile is constrained to the lower part of the Matuyama Chron by an Ar/Ar-age. Except for one flow of intermediate direction (ChM-I), the whole Cha de Morte sequence consists of reverse-polarity flows. The lowermost flow in the Escabecada profile is constrained to the upper part of the Gauss Chron by an Ar/Ar-age. Flows of both reverse and normal polarity are found in the Escabecada profile, corresponding to the lower part of Matuyama and upper part of Gauss, respectively. Two flows with anomalous behaviour, ESC-I and ESC-II, are found in the directional data of this sequence. The uppermost event (ESC-II) most likely recorded the Gauss-Matuyama transition, while the lowermost event

  17. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    NASA Astrophysics Data System (ADS)

    Labarga, Luis

    2010-11-01

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R&D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  18. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    SciTech Connect

    Labarga, Luis

    2010-11-24

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R and D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  19. Hatching success of Caspian terns nesting in the lower Laguna Madre, Texas, USA

    USGS Publications Warehouse

    Mitchell, C.A.; Custer, T.W.

    1986-01-01

    The average clutch size of Caspian Terns nesting in a colony in the Lower Laguna Madre near Laguna Vista, Texas, USA in 1984 was 1.9 eggs per nest. Using the Mayfield method for calculating success, one egg hatched in 84.1% of the nests and 69.8% of the eggs laid hatched. These hatching estimates are as high or higher than estimates from colonies in other areas.

  20. Opportunity's Second Martian Birthday at Cape Verde

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A promontory nicknamed 'Cape Verde' can be seen jutting out from the walls of Victoria Crater in this approximate true-color picture taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity. The rover took this picture on martian day, or sol, 1329 (Oct. 20, 2007), more than a month after it began descending down the crater walls -- and just 9 sols shy of its second Martian birthday on sol 1338 (Oct. 29, 2007). Opportunity landed on the Red Planet on Jan. 25, 2004. That's nearly four years ago on Earth, but only two on Mars because Mars takes longer to travel around the sun than Earth. One Martian year equals 687 Earth days.

    The overall soft quality of the image, and the 'haze' seen in the lower right portion, are the result of scattered light from dust on the front sapphire window of the rover's camera.

    This view was taken using three panoramic-camera filters, admitting light with wavelengths centered at 750 nanometers (near infrared), 530 nanometers (green) and 430 nanometers (violet).

  1. Strategic Analysis for the MER Cape Verde Approach

    NASA Technical Reports Server (NTRS)

    Gaines, Daniel; Belluta, Paolo; Herman, Jennifer; Hwang, Pauline; Mukai, Ryan; Porter, Dan; Jones, Byron; Wood, Eric; Grotzinger, John; Edgar, Lauren; Hayes, Alex; Hare, Trent; Squyres, Steve

    2009-01-01

    The Mars Exploration Rover Opportunity has recently completed a two year campaign studying Victoria Crater. The campaign culminated in a close approach of Cape Verde in order to acquire high resolution imagery of the exposed stratigraphy in the cliff face. The close approach to Cape Verde provided significant challenges for every subsystem of the rover as the rover needed to traverse difficult, uncharacterised terrain and approach a cliff face with the potential of blocking out solar energy and communications with Earth. In this paper we describe the strategic analyses performed by the science and engineering teams so that we could successfully achieve the science objectives while keeping the rover safe.

  2. Strategic analysis for the MER Cape Verde approach

    USGS Publications Warehouse

    Gaines, D.; Belluta, P.; Herman, J.; Hwang, P.; Mukai, R.; Porter, D.; Jones, B.; Wood, E.; Grotzinger, J.; Edgar, L.; Hayes, A.; Hare, T.; Squyres, S.

    2009-01-01

    The Mars Exploration Rover Opportunity has recently completed a two year campaign studying Victoria Crater. The campaign culminated in a close approach of Cape Verde in order to acquire high resolution imagery of the exposed stratigraphy in the cliff face. The close approach to Cape Verde provided significant challenges for every subsystem of the rover as the rover needed to traverse difficult, uncharacterised terrain and approach a cliff face with the potential of blocking out solar energy and communications with Earth. In this paper we describe the strategic analyses performed by the science and engineering teams so that we could successfully achieve the science objectives while keeping the rover safe. ??2009 IEEE.

  3. Laguna Indian Reservation and Acoma Indian Reservation, Laguna-Acoma Junior and Senior High School: Community Background Reports. The National Study of American Indian Education, Series I, No. 16, Final Report.

    ERIC Educational Resources Information Center

    Chilcott, John H.; Garcia, Jerry P.

    Location, climate, population, economy, government, and social conditions of the Laguna and Acoma Indian reservations in New Mexico are discussed in this community background report. In addition, education is discussed in terms of the Laguna-Acoma Junior and Senior High School; this school, which serves students in grades 7 through 12 from both…

  4. Factors controlling navigation-channel Shoaling in Laguna Madre, Texas

    USGS Publications Warehouse

    Morton, R.A.; Nava, R.C.; Arhelger, M.

    2001-01-01

    Shoaling in the Gulf Intracoastal Waterway of Laguna Madre, Tex., is caused primarily by recycling of dredged sediments. Sediment recycling, which is controlled by water depth and location with respect to the predominant wind-driven currents, is minimal where dredged material is placed on tidal flats that are either flooded infrequently or where the water is extremely shallow. In contrast, nearly all of the dredged material placed in open water >1.5 m deep is reworked and either transported back into the channel or dispersed into the surrounding lagoon. A sediment flux analysis incorporating geotechnical properties demonstrated that erosion and not postemplacement compaction caused most sediment losses from the placement areas. Comparing sediment properties in the placement areas and natural lagoon indicated that the remaining dredged material is mostly a residual of initial channel construction. Experimental containment designs (shallow subaqueous mound, submerged levee, and emergent levee) constructed in high-maintenance areas to reduce reworking did not retain large volumes of dredged material. The emergent levee provided the greatest retention potential approximately 2 years after construction.

  5. The LAGUNA/LBNO potential for Long Baseline neutrino physics

    NASA Astrophysics Data System (ADS)

    Agostino, Luca; Consortium, Laguna-Lbno

    2014-12-01

    The LAGUNA/LBNO collaboration proposes a new generation neutrino experiment to address fundamental questions in particle and astroparticle physics. The experiment consists of a far detector, Liquid Argon (LAr) double phase Time TPC (Time Projection Chamber), the fiducial mass of the detector is set to 20 kt in its first stage. The detector will be situated at 2300 km from CERN: this long baseline provides a unique opportunity to study the neutrino flavour oscillations over the first and second oscillation maxima and to explore the L/E (Length over energy) behaviour. The near detector is based on a high-pressure argon gas TPC situated at CERN. I will detail the physics potential of this experiment for determining without ambiguity the mass hierarchy (MH) in its first stage and discovering CP violation (CPV) using the CERN SPS beam with a power of 750 kw. The impact of the assumptions on the knowledge of the oscillation parameters and the systematic errors are very important and will be shown in detail to prove the force of the experiment assuming realistic and conservative parameter values.

  6. High-Performance Wireless Internet Connection to Mount Laguna Observatory

    NASA Astrophysics Data System (ADS)

    Etzel, P. B.; Braun, H.-W.

    2000-12-01

    A 45 Mbit/sec full-duplex wireless Internet backbone is now under construction that will connect SDSU's Mount Laguna Observatory (MLO) to the San Diego Supercomputer Center (SDSC), which is located on the campus of UCSD. The SDSU campus is connected to the SDSC via Abilene/OC3 (Internet2) at 155 Mbit/sec. The MLO-SDSC backbone is part of the High-Performance Wireless Research and Education Network (HPWREN) project. Other scientific applications include earthquake monitoring from a remote array of automated seismic stations operated by researchers at the UCSD Institute for Geophysics and Planetary Physics, and environmental monitoring at Ecology field stations administered by SDSU. Educational initiatives include bringing the Internet to schools and educational centers at remote Indian reservations such as Pala and Rincon. HPWREN will allow SDSU astronomers and their collaborators to transmit CCD images to their home institutions while observations are being made. Archive retrieval of images from on-campus data bases, for comparison purposes, could easily be done. SDSU desires to build a modern, large telescope at MLO. HPWREN would support both robotic and remote observing capabilities for such a telescope. Astronomers could observe at their home institutions with multiple workstations to feed command and control instructions, data, and slow-scan video, which would give them the "feel" of being in a control room next to the telescope. HPWREN was funded by the NSF under grant ANI-0087344.

  7. 77 FR 49455 - Proclaiming Certain Lands as an Addition to and Becoming a Part of the Laguna Reservation for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-16

    ... the Pueblo of Laguna Indian Reservation for the Pueblo of Laguna, New Mexico. FOR FURTHER INFORMATION CONTACT: Ben Burshia, Bureau of Indian Affairs, Division of Real Estate Services, MS-4639-MIB, 1849 C... Reservation Cibola County, New Mexico Those certain parcels of land known as Parcels I and II,...

  8. Mexico City's Indios Verdes: Exploring Cultural Processes Using Public Memorials

    ERIC Educational Resources Information Center

    Dixon, Seth

    2010-01-01

    Finding ways to convey current research in cultural geography that is predicated on theoretical frameworks in a manner accessible to high school and undergraduate college students is pedagogically important but difficult in practice. Statues in Mexico City nicknamed the Indios Verdes offer a rich example of fluid cultural dynamics that illustrate…

  9. Source Apportionment of Particulate Matter Sampled in Cape Verde

    NASA Astrophysics Data System (ADS)

    Marta Almeida, Susana; Almeida-Silva, Marina; Pio, Casimiro; Nunes, Teresa; Cardoso, João; Cerqueira, Mário; Reis, Miguel; Chaves, Paula Cristina; Taborda, Ana

    2013-04-01

    Due to its geographical position, Cape Verde is highly affected by the transport of dust from the Sahara desert. Consequently, very high concentrations of particles are registered in this archipelago, being essential to elucidate the role that Saharan dust may play in the degradation of Cape Verde air quality, human health, wellbeing, visibility, tourism and economy. The objective of this study was to identify the main sources and origins of particles sampled in Cape Verde. PM10 was sampled during 2011 and chemical characterization of particles was performed by Neutron Activation Analysis and Particle Induced X-ray Emission for elemental measurements, by Ion Chromatography for the determination of water soluble ions and by a Thermal-optical system for the measurement of carbonaceous aerosol. Source apportionment was performed by integrating Positive Matrix Factorization and Backward Trajectory Analysis. Results showed that in average 68% of the PM10 mass in Cape Verde had a natural origin, being 48% associated with the soil and 20% associated with the sea. During the transport of dust from the Sahara desert the contribution of mineral aerosol increased significantly (69% during periods affected by trajectories provided from Sahara desert versus 13% during periods affected by local sources).

  10. Dusk Lighting of Layered Textures in 'Cape Verde'

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Full-shade lighting in the late Martian afternoon helps make details visible in this view of the layered cliff face of the 'Cape Verde' promontory making up part of the rim of Victoria Crater in the Meridiani Planum region of equatorial Mars.

    NASA's Mars Exploration Rover Opportunity used its panoramic camera (Pancam) to shoot the dozens of individual images that have been combined into this mosaic. Opportunity was inside Victoria Crater and near the base of the cliff when it took these images on the 1,579th and 1,580th Martian days, or sols, of the mission (July 2 and 3, 2008).

    Photographing the promontory from this position in Victoria Crater presented challenges for the rover team. The geometry was such that Cape Verde was between the rover and the sun, which could cause a range of negative effects, from glinting off Pancam's dusty lenses to shadowing on the cliff face. The team's solution was to take the images for this mosaic just after the sun disappeared behind the crater rim, at about 5:30 p.m. local solar time. The atmosphere was still lit, but no direct sunlight was illuminating the wall of Cape Verde.

    The result is a high-resolution view of Cape Verde in relatively uniform diffuse sky lighting across the scene.

    Pancam used a clear filter for taking the images for this mosaic. Capturing images in low-light situations was one of the main motivations for including the clear filter among the camera's assortment of filters available for use.

    The face of Cape Verde is about 6 meters (20 feet) tall. Victoria Crater, at about 800 meters (one-half mile) wide, is the largest and deepest crater that Opportunity has visited. It sits more than 5 kilometers (almost 4 miles) away from Opportunity's Eagle Crater landing site. Researchers sent Opportunity into Victoria Crater to study the rock layers exposed inside. The textures seen in the rock layers of Cape Verde suggest that the exposed layers were originally deposited by wind.

  11. 78 FR 57545 - Proposed Establishment of Class D Airspace and Class E Airspace; Laguna AAF, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ...'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant...), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The... Proposed Establishment of Class D Airspace and Class E Airspace; Laguna AAF, AZ AGENCY: Federal...

  12. Laguna-Acoma High School Alumni, Classes of 1964 through 1974, Who Have Earned Bachelor's Degrees.

    ERIC Educational Resources Information Center

    Munro, Fern H.

    Students, families, colleges and funding agencies contributed data to determine the educational status of the alumni of Laguna-Acoma High School in New Mexico. Of the 749 students graduating from the school from its opening in 1964 to 1974, sixty-two students, or 8%, received a baccalaureate degree by August of 1978. New Mexico colleges and…

  13. Redhead duck behavior on lower Laguna Madre and adjacent ponds of southern Texas

    USGS Publications Warehouse

    Mitchell, C.A.; Custer, T.W.; Zwank, P.J.

    1992-01-01

    Behavior of redheads (Aythya americana) during winter was studied on the hypersaline lower Laguna Madre and adjacent freshwater to brackish water ponds of southern Texas. On Laguna Madre, feeding (46%) and sleeping (37%) were the most common behaviors. Redheads fed more during early morning (64%) than during the rest of the day (40%); feeding activity was negatively correlated with temperature. Redheads fed more often by dipping (58%) than by tipping (25%), diving (16%), or gleaning (0.1%). Water depth was least where they fed by dipping (16 cm), greatest where diving (75 cm), and intermediate where tipping (26 cm). Feeding sequences averaged 5.3 s for dipping, 8.1 s for tipping, and 19.2 s for diving. Redheads usually were present on freshwater to brackish water ponds adjacent to Laguna Madre only during daylight hours, and use of those areas declined as winter progressed. Sleeping (75%) was the most frequent behavior at ponds, followed by preening (10%), swimming (10%), and feeding (0.4%). Because redheads fed almost exclusively on shoalgrass while dipping and tipping in shallow water and shoalgrass meadows have declined in the lower Laguna Madre, proper management of the remaining shoalgrass habitat is necessary to ensure that this area remains the major wintering area for redheads.

  14. 78 FR 72006 - Establishment of Class D Airspace and Class E Airspace; Laguna AAF, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-02

    ... Register a notice of proposed rulemaking (NPRM) to establish controlled airspace at Laguna AAF, AZ (78 FR... Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a regulatory evaluation... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR,...

  15. 75 FR 74073 - Laguna Atascosa National Wildlife Refuge, Cameron and Willacy Counties, TX; Final Comprehensive...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ... Register July 19, 2004 (69 FR 43010). Laguna Atascosa NWR is located in Cameron and Willacy Counties, Texas.... Management efforts focus on protecting, enhancing, and restoring Refuge habitats and water management for the... Selected Alternative Our draft CCP and our EA (74 FR 66148) addressed several issues. To address these,...

  16. Age of Palos Verdes submarine debris avalanche, southern California

    USGS Publications Warehouse

    Normark, W.R.; McGann, M.; Sliter, R.

    2004-01-01

    The Palos Verdes debris avalanche is the largest, by volume, late Quaternary mass-wasted deposit recognized from the inner California Borderland basins. Early workers speculated that the sediment failure giving rise to the deposit is young, taking place well after sea level reached its present position. A newly acquired, closely-spaced grid of high-resolution, deep-tow boomer profiles of the debris avalanche shows that the Palos Verdes debris avalanche fills a turbidite leveed channel that extends seaward from San Pedro Sea Valley, with the bulk of the avalanche deposit appearing to result from a single failure on the adjacent slope. Radiocarbon dates from piston-cored sediment samples acquired near the distal edge of the avalanche deposit indicate that the main failure took place about 7500 yr BP. ?? 2003 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  18. IN and CCN Measurements on RV Polarstern and Cape Verde

    NASA Astrophysics Data System (ADS)

    Welti, André; Herenz, Paul; Henning, Silvia; Stratmann, Frank

    2016-04-01

    Two field campaigns, one situated on RV Polarstern (Oct. - Dec. 2015) and one on the Cape Verde islands (Jan. - Feb. 2016) measuring ice nuclei (IN) and cloud condensation nuclei (CCN) concentrations as a function of supersaturation and temperature are presented. The Polarstern cruise from Bremerhaven to Cape Town yields a cross section of IN and CCN concentrations from 54°N to 35°S and passes the Cape Verde Islands at 15°N. Measurements were conducted using the commercial CCNC and SPIN instruments from DMT. During both campaigns, a comprehensive set of aerosol characterization data including size distribution, optical properties and chemical information were measured in parallel. The ship based measurements provide a measure of variability in IN/CCN concentration with geographic position. As an example a clear influence on IN and CCN number concentration of the Saharan desert dust outflow between the Canary Islands and Cape Verde or the continental aerosol from Europe and South Africa was observed. The measurements on Cape Verde provide information on the temporal variability at a fixed position varying between clean marine and dust influenced conditions. Both datasets are related to auxiliary data of aerosol size distribution and chemical composition. The datasets are used to distinguish the influence of local sources and background concentration of IN/CCN. By combining of the geographically fix measurements with the geographical cross section, typical ranges of IN and CCN concentration are derived. The datasets will be part of the BACCHUS database thereby providing valuable input for future climate modeling activities.

  19. Trend analysis of selected water-quality constituents in the Verde River Basin, central Arizona

    SciTech Connect

    Baldys, S. )

    1990-01-01

    Temporal trends of eight water quality constituents at six data collection sites in the Verde River basin in central Arizona were investigated using seasonal Kendall tau and ordinary least-squares regression methods of analysis. The constituents are dissolved solids, dissolved sulfate, dissolved arsenic, total phosphorus, pH, total nitrite plus nitrate-nitrogen, dissolved iron, and fecal coliform bacteria. Increasing trends with time in dissolved-solids concentrations of 7 to 8 mg/L/yr at Verde River near Camp Verde were found at significant level. An increasing trend in dissolved-sulfate concentrations of 3.59 mg/L/yr was also found at Verde River near Camp Verde, although at nonsignificant levels. Statistically significant decreasing trends with time in dissolved-solids and dissolved-sulfate concentrations were found at Verde River above Horseshoe Reservoir, which is downstream from Verde River near Camp Verde. Observed trends in the other constituents do not indicate the emergence of water quality problems in the Verde River basin. Analysis of the eight water quality constituents generally indicate nonvarying concentration levels after adjustment for seasonality and streamflow were made.

  20. Migration chronology and distribution of redheads on the lower Laguna Madre, Texas

    USGS Publications Warehouse

    Custer, Christine M.; Custer, T.W.; Zwank, P.J.

    1997-01-01

    An estimated 80% of redheads (Aythya americana) winter on the Laguna Madre of southern Texas and Mexico. Because there have been profound changes in the Laguna Madre over the past three decades and the area is facing increasing industrial and recreational development, we studied the winter distribution and habitat requirements of redheads during two winters (1987-1988 and 1988-1989) on the Lower Laguna Madre, Texas to provide information that could be used to understand, identify, and protect wintering redhead habitat. Redheads began arriving on the Lower Laguna Madre during early October in 1987 and 1988, and continued to arrive through November. Redhead migration was closely associated with passing weather fronts. Redheads arrived on the day a front arrived and during the following two days; no migrants were observed arriving the day before a weather front arrived. Flock size of arriving redheads was 26.4 ± 0.6 birds and did not differ among days or by time of day (morning midday, or afternoon). Number of flocks arriving per 0.5 h interval (arrival rate) was greater during afternoon (21.7 ± 0.6) than during morning (4.3 ± 1.2) or midday (1.5 ± 0.4) on the day of frontal passage and during the first day after frontal passage. Upon arrival, redhead flocks congregated in the central portion of the Lower Laguna Madre. They continued to use the central portion throughout the winter, but gradually spread to the northern and southern ends of the lagoon. Seventy-one percent of the area used by flocks was vegetated with shoalgrass (Halodule wrightii) although shoalgrass covered only 32% of the lagoon. Flock movements seemed to be related to tide level; redheads moved to remain in water 12-30 cm deep. These data can be used by the environmental community to identify and protect this unique and indispensable habitat for wintering redheads.

  1. Vesicularity variation to pyroclasts from silicic eruptions at Laguna del Maule volcanic complex, Chile

    NASA Astrophysics Data System (ADS)

    Wright, H. M. N.; Fierstein, J.; Amigo, A.; Miranda, J.

    2014-12-01

    Crystal-poor rhyodacitic to rhyolitic volcanic eruptions at Laguna del Maule volcanic complex, Chile have produced an astonishing range of textural variation to pyroclasts. Here, we focus on eruptive deposits from two Quaternary eruptions from vents on the northwestern side of the Laguna del Maule basin: the rhyolite of Loma de Los Espejos and the rhyodacite of Laguna Sin Puerto. Clasts in the pyroclastic fall and pyroclastic flow deposits from the rhyolite of Loma de Los Espejos range from dense, non-vesicular (obsidian) to highly vesicular, frothy (coarsely vesicular reticulite); where vesicularity varies from <1% to >90%. Bulk compositions range from 75.6-76.7 wt.% SiO2. The highest vesicularity clasts are found in early fall deposits and widely dispersed pyroclastic flow deposits; the frothy carapace to lava flows is similarly highly vesicular. Pyroclastic deposits also contain tube pumice, and macroscopically folded, finely vesicular, breadcrusted, and heterogeneously vesiculated textures. We speculate that preservation of the highest vesicularities requires relatively low decompression rates or open system degassing such that relaxation times were sufficient to allow extensive vesiculation. Such an inference is in apparent contradiction to documentation of Plinian dispersal to the eruption. Clasts in the pyroclastic fall deposit of the rhyodacite (68-72 wt.% SiO2) of Laguna Sin Puerto are finely vesicular, with vesicularity modes at ~50% and ~68% corresponding to gray and white pumice colors, respectively. Some clasts are banded in color (and vesicularity). All clasts were fragmented into highly angular particles, with subplanar to slightly concave exterior surfaces (average Wadell Roundness of clast margins between 0.32 and 0.39), indicating brittle fragmentation. In contrast to Loma de Los Espejos, high bubble number densities to Laguna Sin Puerto rhyodacite imply high decompression rates.

  2. Strategies for Post-Primary Education in Small Island Developing States (SIDS): Lessons from Cape Verde

    ERIC Educational Resources Information Center

    Atchoarena, David; Da Graca, Patricia Dias; Marquez, Jose Manuel

    2008-01-01

    This article addresses the context and challenges of small island developing states, focusing particularly on Cape Verde. After a general discussion of the characteristics of small island developing states, several development challenges such as poverty, unemployment and migratory issues specific to Cape Verde are evoked. Despite a period of…

  3. Deposition and Accumulation of Emerging Contaminants in the Sediments of the Palos Verde Shelf, California

    EPA Science Inventory

    Deposition and Accumulation of Emerging Contaminants in the Sediments of the Palos Verde Shelf, California Mark G. Cantwell, David R. Katz, Julia Sullivan, Robert P. Eganhouse, Monique M. Perron, Robert M. Burgess The Palos Verdes shelf is located off the Southern California coa...

  4. Trace elements and organochlorines in the shoalgrass community of the lower Laguna Madre

    USGS Publications Warehouse

    Custer, T.W.; Mitchell, C.A.

    1993-01-01

    Our objectives were to measure concentrations of seven trace elements and 14 organochlorine compounds in sediment and biota of the shoalgrass (Halodule wrightii) community of the lower Laguna Madre of south Texas and to determine whether chemicals associated with agriculture (e.g. mercury, arsenic, selenium, organochlorine pesticides) were highest near agricultural drainages. Arsenic, mercury, selenium, lead, cadmium, and organochlorines were generally at background concentrations throughout the lower Laguna Madre. Nickel and chromium concentrations were exceptionally high in shrimp and pinfish (Lagodon rhomboides), which is difficult to explain because of no known anthropogenic sources for these trace elements. For sediment and blue crabs (Callinectes sapidus), mercury was highest near agricultural drainages. Also, DDE was more frequently detected in blue crabs near agricultural drainages than farther away. In contrast, selenium concentrations did not differ among collecting sites and arsenic concentrations were lowest in shoalgrass, blue crabs, and brown shrimp (Penaeus aztecus) near agricultural drainages.

  5. The microbial community at Laguna Figueroa, Baja California Mexico - From miles to microns

    NASA Technical Reports Server (NTRS)

    Stolz, J. F.

    1985-01-01

    The changes in the composition of the stratified microbial community in the sediments at Laguna Figeroa following floods are studied. The laguna which is located on the Pacific coast of the Baja California peninsula 200 km south of the Mexican-U.S. border is comprised of an evaporite flat and a salt marsh. Data collected from 1979-1983 using Landsat imagery, Skylab photographs, and light and transmission electron microscopy are presented. The flood conditions, which included 1-3 m of meteoric water covering the area and a remanent of 5-10 cm of siliciclastic and clay sediment, are described. The composition of the community prior to the flooding consisted of Microcoleus, Phormidium sp., a coccoid cynanobacteria, Phloroflexus, Ectothiorhodospira, Chloroflexus, Thiocapsa sp., and Chromatium. Following the floods Thiocapsa, Chromatium, Oscillatora sp., Spirulina sp., and Microcoleus are observed in the sediments.

  6. Spatial modulation of the hydrological risk at Praia, Cape Verde

    NASA Astrophysics Data System (ADS)

    Lino Silva, José; Neves, Ana Cristina; Garrott Marques Negreiros, João

    2016-06-01

    Hydrology modeling became a relevant topic for the Cidade da Praia, Cabo Verde, Africa, due to negative impact risk to local population and its assets. The modeling via Geographical Information Systems (GIS) can help the decision-making process of space occupation and characterization for this type of risk. Under the municipalities of Praia, the phenomenon of flash flood is common, causing soil erosion and landslide. This constitutes a risk for the local habitat, particularly in districts with a lack of strong human infrastructures. To simulate, analyze and generate risk maps using GIS to help this county governance authorities for decision-making, thus, becomes the main aim of this article.

  7. Hydrocarbon concentrations in sediments and clams (Rangia cuneata) in Laguna de Pom, Mexico

    SciTech Connect

    Alvarez-Legorreta, T.; Gold-Bouchot, G.; Zapata-Perez, O.

    1994-01-01

    Laguna de Pom is a coastal lagoon within the Laguna de Terminos system in southern Gulf of Mexico. It belongs to the Grijalva-Usumacinta basin, and is located between 18{degrees} 33{prime} and 18{degrees} 38{prime} north latitude and 92{degrees} 01{prime} and 92{degrees} 14{prime} west longitude, in the Coastal Plain physiographic Province of the Gulf. It is ellipsoidal and approximately 10 km long, with a surface area of 5,200 ha and a mean depth of 1.5 m. Water salinity and temperature ranges are 0 to 13 {per_thousand} and 25{degrees} to 31{degrees}C, respectively. Benthic macrofauna is dominated by bivalves such as the clams Rangia cuneata, R. flexuosa, and Polymesoda carolineana. These clams provide the basis of an artisanal fishery, which is the main economic activity in the region. The presence of several oil-processing facilities around the lagoon is very conspicuous, which together with decreasing yields has created social conflicts, with the fishermen blaming the mexican state oil company (PEMEX) for the decrease in the clam population. This work aims to determine if the concentration of hydrocarbons in the clams (R. cuneata) and sediments of Laguna de Pom are responsible for the declining clam fishery. 11 refs., 4 figs., 2 tabs.

  8. Uncertainty in low-flow data from three streamflow-gaging stations on the upper Verde River, Arizona

    USGS Publications Warehouse

    Anning, D.W.

    2004-01-01

    The evaluation of uncertainty in low-flow data collected from three streamflow-gaging stations on the upper Verde River, Arizona, was presented. In downstream order, the stations are Verde River near Paulden, Verde River near Clarkdale, and Verde River near Camp Verde. A monitoring objective of the evaluation was to characterize discharge of the lower flow regime through a variety of procedures such as frequency analysis and base-flow analysis. For Verde River near Paulden and near Camp Verde, the uncertainty of daily low flows can be reduced by decreasing the uncertainty of discharge-measurement frequency, or building an artificial control that would have a stable stage-discharge relation over time.

  9. Update-processing steam generator cleaning solvent at Palo Verde

    SciTech Connect

    Peters, G.

    1996-10-01

    Framatome Technologies Inc.(FTI) recently completed the steam generator chemical cleanings at the Palo Verde Nuclear Generating Station Units 1, 2 and 3. Over 500,000 gallons of low-level radioactive solvents were generated during these cleanings and were processed on-site. Chemical cleaning solutions containing high concentrations of organic chelating wastes are difficult to reduce in volume using standard technologies. The process that was ultimately used at Palo Verde involved three distinct processing steps: The evaporation step was conducted using FTI`s submerged combustion evaporator (SCE) that has also been successfully used at Arkansas Nuclear One - Unit 1, Three Mile Island - Unit 1, and Oconee on similar waste. The polishing step of the distillate used ultrafiltration (UF) and reverse osmosis (RO) technology that was also used extensively by Ontario Hydro to assist in their processing of chemical cleaning solvent. This technology, equipment, and operations personnel were provided by Zenon Environmental, Inc. The concentrate from the evaporator was absorbed with a special {open_quotes}peat moss{close_quotes} based media that allowed it to be shipped and buried at the Environcare of Utah facility. This is the first time that this absorption media or burial site has been used for chemical cleaning solvent.

  10. Geotourism, Medical Geology and local development: Cape Verde case study

    NASA Astrophysics Data System (ADS)

    Rocha, F.; Ferreira da Silva, E.

    2014-11-01

    Geotourism and Geoparks in particular are real opportunities to rural developments promoting the rate decline of unemployment and emigration through engaging the local communities in geopark activities and tourism marketing in the form of adventure tourism, ecotourism, rural tourism and health geotourism. Geotourism is closely linked with Medical Geology. The intake of minerals and chemical elements for food, water, soil (through geophagy) or dust can be accomplished by ingestion, inhalation or dermal absorption. Pelotherapy or “Mudtherapy” is the use of mud/clay for therapeutic applications, internal or external. Cape Verde archipelago is located in Atlantic ocean, 400 km westwards of Senegal coast. Geotourism is being developed, mainly focused on the development of a geopark in Fogo island huge caldera, but also trying to take advantage of their potentialities for Geomedecine. A cooperative program established between Cape Verde University (UCV) and Aveiro University (UA, Portugal) is under way, aiming, on a first stage, to identify Geotouristic potentialities and, on a second stage, to develop products. Geotourism is being developed, mainly focused on the development of a geopark in Fogo isl. huge caldera, but also trying to take advantage of their potentialities for Geomedecine.

  11. Hydrogeology of the upper and middle Verde River watersheds, central Arizona

    USGS Publications Warehouse

    Blasch, Kyle W.; Hoffmann, John P.; Graser, Leslie F.; Bryson, Jeannie R.; Flint, Alan L.

    2006-01-01

    The upper and middle Verde River watersheds in central Arizona are primarily in Yavapai County, which in 1999 was determined to be the fastest growing rural county in the United States; by 2050 the population is projected to more than double its current size (132,000 in 2000). This study combines climatic, surface-water, ground-water, water-chemistry, and geologic data to describe the hydrogeologic systems within the upper and middle Verde River watersheds and to provide a conceptual understanding of the ground-water flow system. The study area includes the Big Chino and Little Chino subbasins in the upper Verde River watershed and the Verde Valley subbasin in the middle Verde Rive watershed...more...A geochemical mixing model was used to quantify fractions of ground-water sources to the Verde River from various parts of the study area. Most of the water in the uppermost 0.2 mile of the Verde River is from the Little Chino subbasin, and the remainder is from the Big Chino subbasin. Discharge from a system of springs increases base flow to about 17 cubic feet per second within the next 2 miles of the river. Ground water that discharges at these springs is derived from the western part of the Coconino Plateau, from the Big Chino subbasin, and from the Little Chino subbasin. More...

  12. New species of mayflies (Ephemeroptera) from Cape Verde.

    PubMed

    Soldán, Tomáš; Bojková, Jindřiška

    2015-01-01

    To date, no mayflies have been described from Cape Verde, an archipelago of volcanic islands in the Atlantic Ocean. Based on the material collected on two islands, Santo Antão and Santiago, two species of the genus Cloeon Leach, 1815 (Ephemeroptera: Baetidae) are described based on larvae and imagines. Cloeon morna sp. n., collected in Santo Antão, and C. sidadi sp. n., collected in Santiago, have 3-segmented maxillary palps and tapered labial palps of larvae. The new species can be distinguished from each other and from other West-African species of the genus mainly according to details of the lateral spines on larval abdominal segments and characteristic colourations of vitta and terga in female imagines and colours of male turbinate eyes. Affinities to the West African species of the genus are discussed. PMID:25781802

  13. Layers of 'Cape Verde' in 'Victoria Crater' (Stereo)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This view of Victoria crater is looking north from 'Duck Bay' towards the dramatic promontory called 'Cape Verde.' The dramatic cliff of layered rocks is about 50 meters (about 165 feet) away from the rover and is about 6 meters (about 20 feet) tall. The taller promontory beyond that is about 100 meters (about 325 feet) away, and the vista beyond that extends away for more than 400 meters (about 1300 feet) into the distance. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.

  14. Layers of 'Cape Verde' in 'Victoria Crater' (Enhanced)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This view of Victoria crater is looking north from 'Duck Bay' towards the dramatic promontory called 'Cape Verde.' The dramatic cliff of layered rocks is about 50 meters (about 165 feet) away from the rover and is about 6 meters (about 20 feet) tall. The taller promontory beyond that is about 100 meters (about 325 feet) away, and the vista beyond that extends away for more than 400 meters (about 1300 feet) into the distance. This is a false color rendering (enhanced to bring out details from within the shadowed regions of the scene) of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  15. Layers of 'Cape Verde' in 'Victoria Crater' (False Color)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This view of Victoria crater is looking north from 'Duck Bay' towards the dramatic promontory called 'Cape Verde.' The dramatic cliff of layered rocks is about 50 meters (about 165 feet) away from the rover and is about 6 meters (about 20 feet) tall. The taller promontory beyond that is about 100 meters (about 325 feet) away, and the vista beyond that extends away for more than 400 meters (about 1300 feet) into the distance. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  16. Effects of past and future groundwater development on the hydrologic system of Verde Valley, Arizona

    USGS Publications Warehouse

    Garner, Bradley D.; Pool, D.R.

    2013-01-01

    Communities in central Arizona’s Verde Valley must manage limited water supplies in the face of rapidly growing populations. Developing groundwater resources to meet human needs has raised questions about the effects of groundwater withdrawals by pumping on the area’s rivers and streams, particularly the Verde River. U.S. Geological Survey hydrologists used a regional groundwater flow model to simulate the effects of groundwater pumping on streamflow in the Verde River. The study found that streamflow in the Verde River between 1910 and 2005 had been reduced as the result of streamflow depletion by groundwater pumping, also known as capture. Additionally, using three hypothetical scenarios for a period from 2005 to 2110, the study’s findings suggest that streamflow reductions will continue and may increase in the future.

  17. A comprehensive analysis of the performance characteristics of the Mount Laguna solar photovoltaic installation

    NASA Technical Reports Server (NTRS)

    Shumka, A.; Sollock, S. G.

    1981-01-01

    This paper represents the first comprehensive survey of the Mount Laguna Photovoltaic Installation. The novel techniques used for performing the field tests have been effective in locating and characterizing defective modules. A comparative analysis on the two types of modules used in the array indicates that they have significantly different failure rates, different distributions in degradational space and very different failure modes. A life cycle model is presented to explain a multimodal distribution observed for one module type. A statistical model is constructed and it is shown to be in good agreement with the field data.

  18. Rock Magnetic Properties of Laguna Carmen (Tierra del Fuego, Argentina): Implications for Paleomagnetic Reconstruction

    NASA Astrophysics Data System (ADS)

    Gogorza, C. G.; Orgeira, M. J.; Ponce, F.; Fernández, M.; Laprida, C.; Coronato, A.

    2013-05-01

    We report preliminary results obtained from a multi-proxy analysis including paleomagnetic and rock-magnetic studies of two sediment cores of Laguna Carmen (53°40'60" S 68°19'0" W, ~83m asl) in the semiarid steppe in northern Tierra del Fuego island, Southernmost Patagonia, Argentina. Two short cores (115 cm) were sampled using a Livingstone piston corer during the 2011 southern fall. Sediments are massive green clays (115 to 70 cm depth) with irregularly spaced thin sandy strata and lens. Massive yellow clay with thin sandy strata continues up to 30 cm depth; from here up to 10 cm yellow massive clays domain. The topmost 10 cm are mixed yellow and green clays with fine sand. Measurements of intensity and directions of Natural Remanent Magnetization (NRM), magnetic susceptibility, isothermal remanent magnetization, saturation isothermal remanent magnetization (SIRM), back field and anhysteretic remanent magnetization at 100 mT (ARM100mT) were performed and several associated parameters calculated (ARM100mT/k and SIRM/ ARM100mT). Also, as a first estimate of relative magnetic grain-size variations, the median destructive field of the NRM (MDFNRM), was determined. Additionally, we present results of magnetic parameters measured with vibrating sample magnetometer (VSM). The stability of the NRM was analyzed by alternating field demagnetization. The magnetic properties have shown variable values, showing changes in both grain size and concentration of magnetic minerals. It was found that the main carrier of remanence is magnetite with the presence of hematite in very low percentages. This is the first paleomagnetic study performed in lakes located in the northern, semiarid fuegian steppe, where humid-dry cycles have been interpreted all along the Holocene from an aeolian paleosoil sequence (Orgeira et el, 2012). Comparison between paleomagnetic records of Laguna Carmen and results obtained in earlier studies carried out at Laguna Potrok Aike (Gogorza et al., 2012

  19. Niebla ceruchis from Laguna Figueroa: dimorphic spore morphology and secondary compounds localized in pycnidia and apothecia

    NASA Technical Reports Server (NTRS)

    Enzien, M.; Margulis, L.

    1988-01-01

    During and after the floods of 1979-80 Niebla ceruchis growing epiphytically on Lycium brevipes was one of the dominant aspects of the vegetation in the coastal dunal complex bordering the microbial mats at Laguna Figueroa, Baja California Norte, Mexico. The lichen on denuded branches of Lycium was far more extensively distributed than Lycium lacking lichen. Unusual traits of this Niebla ceruchis strain, namely localization of lichen compounds in the mycobiont reproductive structures (pycnidia and apothecia) and simultaneous presence of bilocular and quadrilocular ascospores, are reported. The abundance of this coastal lichen cover at the microbial mat site has persisted through April 1988.

  20. Water resources on the Pueblo of Laguna, west-central New Mexico

    USGS Publications Warehouse

    Risser, D.W.; Lyford, F.P.

    1983-01-01

    This study evaluates the quality and quantity of water available on the Pueblo of Laguna, New Mexico. Groundwater for public supply occurs in the valley fill along the Rio San Jose, in the Paguate and Encinal areas, and possibly in the northern part of the Sedillo Grant. The valley fill in the Rio San Jose will supply 50 to 450 gallons per minute of potable water to properly constructed wells. In the alluvium along Rio Paguate, additional development of as much as 250 gallons per minute is possible. Groundwater for irrigation is restricted by available yields and quality to the valley fill along the Rio San Jose and possibly the western part of the Major 's Ranch area. In the Rio San Jose valley yields of 50 to 450 gallons per minute of water containing 500 to 3,000 milligrams per liter are possible. Digital-model simulations of the valley-fill aquifer west of the Village of Laguna show a potential salvage of as much as 900 acre-feet per year of evapotranspiration losses if water levels are lowered. Model studies also indicate that the winter flow of the Rio San Jose could be used to recharge groundwater stored in the valley. (USGS)

  1. Water-quality reconnaissance of Laguna Tortuguero, Vega Baja, Puerto Rico, March 1999-May 2000

    USGS Publications Warehouse

    Soler-Lopez, Luis; Guzman-Rios, Senen; Conde-Costas, Carlos

    2006-01-01

    The Laguna Tortuguero, a slightly saline to freshwater lagoon in north-central Puerto Rico, has a surface area of about 220 hectares and a mean depth of about 1.2 meters. As part of a water-quality reconnaissance, water samples were collected at about monthly and near bi-monthly intervals from March 1999 to May 2000 at four sites: three stations inside the lagoon and one station at the artificial outlet channel dredged in 1940, which connects the lagoon with the Atlantic Ocean. Physical characteristics that were determined from these water samples were pH, temperature, specific conductance, dissolved oxygen, dissolved oxygen saturation, and discharge at the outlet canal. Other water-quality constituents also were determined, including nitrogen and phosphorus species, organic carbon, chlorophyll a and b, plankton biomass, hardness, alkalinity as calcium carbonate, and major ions. Additionally, a diel study was conducted at three stations in the lagoon to obtain data on the diurnal variation of temperature, specific conductance, dissolved oxygen, and dissolved oxygen saturation. The data analysis indicates the water quality of Laguna Tortuguero complies with the Puerto Rico Environmental Quality Board standards and regulations.

  2. Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

    2009-04-01

    Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of

  3. A 20,000-year record of environmental change from Laguna Kollpa Kkota, Bolivia

    SciTech Connect

    Seltzer, G.O. . Mendenhall Lab.); Abbott, M.B. )

    1992-01-01

    Most records of paleoclimate in the Bolivian Andes date from the last glacial-to-interglacial transition. However, Laguna Kollpa Kkota and other lakes like it, formed more than 20,000 yr BP when glaciers retreated and moraines dammed the drainage of the valleys they are located in. These lakes were protected from subsequent periods of glaciation because the headwalls of these valleys are below the level of the late-Pleistocene glacial equilibrium-line altitude. The chemical, mineral, and microfossil stratigraphies of these glacial lakes provide continuous records of environmental change for the last 20,000 years that can be used to address several problems in paleoclimate specific to tropical-subtropical latitudes. Preliminary results from Laguna Kollpa Kkota indicate that glacial equilibrium-line altitudes were never depressed more than 600 m during the last 20,000 years, suggesting that temperatures were reduced only a few-degrees celsius over this time period. Sedimentation rates and the organic carbon stratigraphy of cores reflect an increase in moisture in the late Pleistocene just prior to the transition to a warmer and drier Holocene. The pollen and diatom concentrations in the sediments are sufficient to permit the high resolution analyses needed to address whether or not there were climatic reversals during the glacial-to-interglacial transition.

  4. Palaeomagnetic Investigations on Santo Antao, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Knudsen, M. F.; Abrahamsen, N.

    2001-12-01

    Samples from five hitherto fairly unexplored young volcanic islands in the Cape Verde Archipelago have been collected for palaeomagnetic studies. Magnetic results from lava flows in 5 profiles located on the island Santo Antão are reported. The Cape Verde Rise situated over the Mesozoic marine anomalies M2-M16, is the result of a slow eastward movement of the Atlantic oceanic lithosphere relative to a hotspot commencing around 20 Ma ago. The uplifted segment of deformed Jurassic oceanic crust seems to be unrelated to the bulk of the igneous activity, which took place during the Neogene. The oldest outcrops encountered on Santo Antão are deeply weathered basalts with an age of 7.57 +/- 0.56 Ma, whereas the investigated profiles cover a time interval from 2.67 +/- 0.05 Ma to 0.38 +/- 0.05 Ma. Investigation of some basic mineral magnetic properties reveal titanomagnetite composition as a general feature, and a pseudo-single-domain behaviour of all lava flows subjected to hysteresis-experiments are found. Flows of normal polarity characterise the Tarrafal Profile, being confined to the Brunhes Chron by 40Ar/39Ar-datings. Two events of reverse polarity are recorded in the stratigraphic column and appear to represent the Big Lost and Emperor Subchrons. The minimum eruption frequency is estimated to be one flow every 2.5 +/- 2.2 Ka. The Agua Nova Profile is likewise dominated by flows of normal polarity belonging to the Brunhes Chron and further contains a few events of reverse polarity. The relatively complex stratigraphy of accessible flows encountered in the Ribeira Grande Area makes the correlation with the global polarity time-scale tentative. The Escabecada Profile records the transition between the lower part of Matuyama and the upper part of the Gauss Chron, and a minimum eruption frequency is estimated to be one flow every 10 +/- 7.1 Ka for the lower part of this profile. The Chã de Morte Profile consists merely of reverse-polarity lava flows belonging to the

  5. HLA polymorphisms in Cabo Verde and Guiné-Bissau inferred from sequence-based typing.

    PubMed

    Spínola, Hélder; Bruges-Armas, Jácome; Middleton, Derek; Brehm, António

    2005-10-01

    Human leukocyte antigen (HLA)-A, -B, and -DRB1 polymorphisms were examined in the Cabo Verde and Guiné-Bissau populations. The data were obtained at high-resolution level, using sequence-based typing. The most frequent alleles in each locus was: A*020101 (16.7% in Guiné-Bissau and 13.5% in Cabo Verde), B*350101 (14.4% in Guiné-Bissau and 13.2% in Cabo Verde), DRB1*1304 (19.6% in Guiné-Bissau), and DRB1*1101 (10.1% in Cabo Verde). The predominant three loci haplotype in Guiné-Bissau was A*2301-B*1503-DRB1*1101 (4.6%) and in Cabo Verde was A*3002-B*350101-DRB1*1001 (2.8%), exclusive to northwestern islands (5.6%) and absent in Guiné-Bissau. The present study corroborates historic sources and other genetic studies that say Cabo Verde were populated not only by Africans but also by Europeans. Haplotypes and dendrogram analysis shows a Caucasian genetic influence in today's gene pool of Cabo Verdeans. Haplotypes and allele frequencies present a differential distribution between southeastern and northwestern Cabo Verde islands, which could be the result of different genetic influences, founder effect, or bottlenecks. Dendrograms and principal coordinates analysis show that Guineans are more similar to North Africans than other HLA-studied sub-Saharans, probably from ancient and recent genetic contacts with other peoples, namely East Africans. PMID:16386651

  6. Laguna Reservation Manpower Resources. Indian Manpower Resources in the Southwest: A Pilot Study. Occasional Paper Number 6.

    ERIC Educational Resources Information Center

    Taylor, Benjamin J.; O'Connor, Dennis J.

    A pilot study reported in this monograph is part of a larger study that includes data on 5 Southwestern American Indian reservations. Its primary purpose is to provide basic manpower information essential for planning and developing effective services and programs for Laguna Indians. Manpower resource characteristics are presented for age and sex,…

  7. A Comparison of Laguna-Acoma High School's Class of 1972 With Similar Schools in New Mexico.

    ERIC Educational Resources Information Center

    Munro, Fern H.

    Data collected by the New Mexico State Department of Education in the spring 1973 are used in tables to compare the 1972 Laguna Acoma High School (LAHS) graduating class and other 1972 New Mexico high school graduating classes. The percentage of 1972 LAHS graduates who at the time of the study were involved in post-secondary academic education or…

  8. Winter distributions of North American Plovers in the Laguna Madre regions of Tamaulipas, Mexico and Texas, USA

    USGS Publications Warehouse

    Mabee, Todd J.; Plissner, Jonathan H.; Haig, Susan M.; Goossen, J.P.

    2001-01-01

    To determine the distribution and abundance of wintering plovers in the Laguna Madre of Texas and Tamaulipas, surveys were conducted in December 1997 and February 1998, along a 160 km stretch of barrier islands in Mexico and- 40 km of shoreline on South Padre Island, Texas. Altogether, 5,673 individuals, representing six plover species, were recorded during the surveys. Black-bellied Plovers Pluvialis squatarola were the most numerous (3 ,013 individuals) representing 53% of the total number of plovers observed. Numbers of Piping Charadriusm elodu, Snowy C . alexandrinus, Semipalmated C. semipalmatus and Wilson's Plovers C. wilsonia were 739, 1,345, 561, and 13 birds, respectively. Most individuals (97%) of all species except Wilson's Plovers were observed on bayside flats of the barrier islands. Similar numbers of Piping Plovers were recorded at South Padre Island, Texas, and in the Laguna Madre de Tamaulipas. Over 85% of the individuals of each of the other species were found in the more extensively surveyed Mexico portion of Laguna Madre. In Tamaulipas, most plover species were observed more often on algal flats than any other substrate. These results provide evidence of the value of these systems as wintering areas for plover species and indicate the need for more extensive survey efforts to determine temporal and spatial variation in the distribution of these species within the Laguna ecosystem.

  9. Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

    2009-04-01

    Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of

  10. Salt lake Laguna de Fuente de Piedra (S-Spain) as Late Quaternary palaeoenvironmental archive

    NASA Astrophysics Data System (ADS)

    Höbig, Nicole; Melles, Martin; Reicherter, Klaus

    2014-05-01

    This study deals with Late Quaternary palaeoenvironmental variability in Iberia reconstructed from terrestrial archives. In southern Iberia, endorheic basins of the Betic Cordilleras are relatively common and contain salt or fresh-water lakes due to subsurface dissolution of Triassic evaporites. Such precipitation or ground-water fed lakes (called Lagunas in Spanish) are vulnerable to changes in hydrology, climate or anthropogenic modifications. The largest Spanish salt lake, Laguna de Fuente de Piedra (Antequera region, S-Spain), has been investigated and serves as a palaeoenvironmental archive for the Late Pleistocene to Holocene time interval. Several sediment cores taken during drilling campaigns in 2012 and 2013 have revealed sedimentary sequences (up to 14 m length) along the shoreline. A multi-proxy study, including sedimentology, geochemistry and physical properties (magnetic susceptibility) has been performed on the cores. The sedimentary history is highly variable: several decimetre thick silty variegated clay deposits, laminated evaporites, and even few-centimetre thick massive gypsum crystals (i.e., selenites). XRF analysis was focussed on valuable palaeoclimatic proxies (e.g., S, Zr, Ti, and element ratios) to identify the composition and provenance of the sediments and to delineate palaeoenvironmental conditions. First age control has been realized by AMS-radiocarbon dating. The records start with approximately 2-3 m Holocene deposits and reach back to the middle of MIS 3 (GS-3). The sequences contain changes in sedimentation rates as well as colour changes, which can be summarized as brownish-beige deposits at the top and more greenish-grey deposits below as well as highly variegated lamination and selenites below ca. 6 m depth. The Younger Dryas, Bølling/Allerød, and the so-called Mystery Interval/Last Glacial Maximum have presumably been identified in the sediment cores and aligned to other climate records. In general, the cores of the Laguna de

  11. 78 FR 34373 - Campo Verde Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Campo Verde Solar, LLC; Supplemental Notice That Initial Market- Based Rate...-referenced proceeding of Campo Verde Solar, LLC's application for market-based rate authority, with...

  12. 77 FR 38280 - Verde Energy USA New York, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Verde Energy USA New York, LLC; Supplemental Notice That Initial Market... in the above-referenced proceeding of Verde Energy USA New York, LLC's application for...

  13. 78 FR 32240 - Notice of Inent (NOI) To Prepare an Environmental Impact Statement (EIS) for the Oro Verde Solar...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... of Inent (NOI) To Prepare an Environmental Impact Statement (EIS) for the Oro Verde Solar Project at..., California to evaluate potential environmental impacts associated with the development of the Oro Verde Solar Project (OVSP) on Edwards AFB. The OVSP is a solar photovoltaic (PV) facility that involves the lease...

  14. 77 FR 14058 - Santa Teresa Southern Railroad, LLC-Operation Exemption-Rail Line of Verde Logistics Railroad...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-08

    ... Logistics Railroad, LLC at Santa Teresa, Dona Ana County, NM Santa Teresa Southern Railroad, LLC (STSR), a... feet of rail line owned by Verde Logistics Railroad, LLC (Verde). The rail line extends between a point... to shippers and receivers located in the Santa Teresa Logistics Industrial Park. \\1\\ STSR states...

  15. Mitochondrial portrait of the Cabo Verde archipelago: the Senegambian outpost of Atlantic slave trade.

    PubMed

    Brehm, A; Pereira, L; Bandelt, H-J; Prata, M J; Amorim, A

    2002-01-01

    In order to study the matrilineal genetic composition in Cabo Verde (Republic of Cape Verde), an archipelago that used to serve as a Portuguese entrepôt of the Atlantic slave trade, we have analysed a total of 292 mtDNAs sampled from the seven inhabited islands for the hypervariable segment I (HVS-I) and some characteristic RFLPs of the coding regions. The different settlement history of the northwestern group of the islands is well reflected in the mtDNA pool. The total Cabo Verde sample clearly displays the characteristic mitochondrial features of the Atlantic fringe of western Africa and testifies to almost no mitochondrial input from the Portuguese colonizers. PMID:12015000

  16. Groundwater Resources of Ribeira Faja Basin, Island of Sao Nicolau, Cape Verde, West Africa

    USGS Publications Warehouse

    Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, L. Niel; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  17. Groundwater Resources of Ribeira Paul Basin, Island of Santo Antao, Cape Verde, West Africa

    USGS Publications Warehouse

    Heilweil, Victor M.; Gingerich, Stephen B.; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  18. Groundwater Resources of Mosteiros Basin, Island of Fogo, Cape Verde, West Africa

    USGS Publications Warehouse

    Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, L. Niel; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  19. Monitoring of streamflow in the Verde River by ERTS-1 Data Collection System (DCS)

    NASA Technical Reports Server (NTRS)

    Schumann, H. H.

    1973-01-01

    The Verde River watershed in central Arizona furnishes municipal, industrial, and agricultural water to the Salt River Valley --an area that contains more than half of Arizona's population and about one-fourth of the State's irrigated land. Water-management decisions related to the operation of large multiple-use reservoirs require accurate and continuous monitoring of moisture conditions over large remote areas. The U.S. Geological Survey in cooperation with the Salt River Valley Water Users' Association installed a specially designed gaging station on the Verde River near the town of Camp Verde to evaluate near-real time streamflow data furnished by the ERTS-1 Data Collection System (DCS). On Nov. 3, 1972, the installation was equipped with a Stevens digital water-level recorder, modified for telemetry, and an ERTS-1 data collection platform operating in the digital-parallel mode.

  20. Remote sensing and numerical modeling of suspended sediment in Laguna de Terminos, Campeche, Mexico

    NASA Technical Reports Server (NTRS)

    Jensen, John R.; Kjerfve, Bjorn; Ramsey, Elijah W., III; Magill, Karen E.; Medeiros, Carmen

    1989-01-01

    It is necessary to understand the complex physical processes at work in coastal lagoons in order to manage them effectively. Improved methods of data collection and analysis must be found to provide synoptic, timely hydrodynamic information because of the sheer size of some lagoons and the difficulty of acquiring in situ data (particularly in the tropics). This paper summarizes research to model salinity and suspended sediment distributions in Laguna de Terminos, Mexico, using (1) a coupled hydrodynamic and dispersion model and (2) analysis of two Landsat Thematic Mapper images collected on November 25, 1984 and April 24, 1987. Atmospherically corrected chromaticity data derived from Thermatic Mapper data were significantly correlated with modeled total suspended sediment concentrations for the two dates. Comparison between numerically modeled and remotely sensed suspended sediment maps at 1.5 x 1.5 km resolution yielded a covariation map useful for identifying areas of discrepancy between the remotely sensed data and model output.

  1. Late Pleistocene-early Holocene karst features, Laguna Madre, south Texas: A record of climate change

    SciTech Connect

    Prouty, J.S.

    1996-09-01

    A Pleistocene coquina bordering Laguna Madre, south Texas, contains well-developed late Pleistocene-early Holocene karst features (solution pipes and caliche crusts) unknown elsewhere from coastal Texas. The coquina accumulated in a localized zone of converging longshore Gulf currents along a Gulf beach. The crusts yield {sup 14}C dates of 16,660 to 7630 B.P., with dates of individual crust horizons becoming younger upwards. The karst features provide evidence of regional late Pleistocene-early Holocene climate changes. Following the latest Wisconsinan lowstand 18,000 B.P. the regional climate was more humid and promoted karst weathering. Partial dissolution and reprecipitation of the coquina formed initial caliche crust horizons; the crust later thickened through accretion of additional carbonate laminae. With the commencement of the Holocene approximately 11,000 B.P. the regional climate became more arid. This inhibited karstification of the coquina, and caliche crust formation finally ceased about 7000 B.P.

  2. Water quality mapping of Laguna de Bay and its watershed, Philippines

    NASA Astrophysics Data System (ADS)

    Saito, S.; Nakano, T.; Shin, K.; Maruyama, S.; Miyakawa, C.; Yaota, K.; Kada, R.

    2011-12-01

    Laguna de Bay (or Laguna Lake) is the largest lake in the Philippines, with a surface area of 900 km2 and its watershed area of 2920 km2 (Santos-Borja, 2005). It is located on the southwest part of the Luzon Island and its watershed contains 5 provinces, 49 municipalities and 12 cities, including parts of Metropolitan Manila. The water quality in Laguna de Bay has significantly deteriorated due to pollution from soil erosion, effluents from chemical industries, and household discharges. In this study, we performed multiple element analysis of water samples in the lake and its watersheds for chemical mapping, which allows us to evaluate the regional distribution of elements including toxic heavy metals such as Cd, Pb and As. We collected water samples from 24 locations in Laguna de Bay and 160 locations from rivers in the watersheds. The sampling sites of river are mainly downstreams around the lake, which covers from urbanized areas to rural areas. We also collected well water samples from 17 locations, spring water samples from 10 locations, and tap water samples from 21 locations in order to compare their data with the river and lake samples and to assess the quality of household use waters. The samples were collected in dry season of the study area (March 13 - 17 and May 2 - 9, 2011). The analysis was performed at the Research Institute for Humanity and Nature (RIHN), Japan. The concentrations of the major components (Cl, NO3, SO4, Ca, Mg, Na, and K) dissolved in the samples were determined with ion chromatograph (Dionex Corporation ICS-3000). We also analyzed major and trace elements (Li, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn Ga, Ge, As, Se, Rb, Sr, Y, Zr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Pb and U) with inductively coupled plasma-mass spectrometry (ICP-MS, Agilent Technologies 7500cx). The element concentrations of rivers are characterized by remarkable regional variations. For

  3. Response of shoal grass, Halodule wrightii, to extreme winter conditions in the Lower Laguna Madre, Texas

    USGS Publications Warehouse

    Hicks, D.W.; Onuf, C.P.; Tunnell, J.W.

    1998-01-01

    Effects of a severe freeze on the shoal grass, Halodule wrightii, were documented through analysis of temporal and spatial trends in below-ground biomass. The coincidence of the second lowest temperature (-10.6??C) in 107 years of record, 56 consecutive hours below freezing, high winds and extremely low water levels exposed the Laguna Madre, TX, to the most severe cold stress in over a century. H. wrightii tolerated this extreme freeze event. Annual pre- and post-freeze surveys indicated that below-ground biomass estimated from volume was Unaffected by the freeze event. Nor was there any post-freeze change in biomass among intertidal sites directly exposed to freezing air temperatures relative to subtidal sites which remained submerged during the freezing period.

  4. Genetic structure of the population of Cabo Verde (west Africa): evidence of substantial European admixture.

    PubMed

    Parra, E J; Ribeiro, J C; Caeiro, J L; Riveiro, A

    1995-08-01

    The population of Cabo Verde was founded in the fifteenth century (1462), on the basis of slaves brought from the West African coast and a few Europeans, mainly from Portugal. The polymorphism of six red cell enzymes (ADA, AK1, ALAD, ESD, GLO1, and PGD) and ten plasma proteins (AHSG, BF, F13A, F13B, GC, HP, ORM, PLG, TBG, and TF) was studied in a sample of 268 individuals from Cabo Verde (West Africa). There is no statistical evidence of genetic heterogeneity between the two groups of islands which constitute the archipelago, Barlavento and Sotavento. The gene frequency distribution observed in Cabo Verde differs, in many markers, from that of West African populations, suggesting an important European influence. The proportion of Caucasian genes in the population of Cabo Verde has been calculated to be M = 0.3634 +/- 0.0510, and the considerable dispersion of the locus-specific admixture estimates seems to indicate random drift has also played a role in the evolution of the allele frequencies in the archipelago. Partition of the variance of the mean estimate in evolutionary and sampling variance shows the evolutionary variance is more than ten times higher than the sampling variance. When dendrograms are constructed on the basis of different genetic distances, the population of Cabo Verde clusters with Afro-Americans, forming a different group from the populations of the African continent. This is interpreted as a consequence of the importance of Caucasian admixture both in Afro-Americans and in the population of Cabo Verde. PMID:7485435

  5. Bats of Mesa Verde National Park, Colorado: composition, reproduction, and roosting habits.

    USGS Publications Warehouse

    O'Shea, Thomas J.; Cryan, Paul M.; Snider, E. Apple; Valdez, Ernest W.; Ellison, Laura E.; Neubaum, Daniel J.

    2011-01-01

    We determined the bat fauna at Mesa Verde National Park (Mesa Verde) in 2006 and 2007, characterized bat elevational distribution and reproduction, and investigated roosting habits of selected species. We captured 1996 bats of 15 species in mist nets set over water during 120 nights of sampling and recorded echolocation calls of an additional species. The bat fauna at Mesa Verde included every species of bat known west of the Great Plains in Colorado, except the little brown bat (Myotis lucifugus). Some species showed skewed sex ratios, primarily due to a preponderance of males. Thirteen species of bats reproduced at Mesa Verde. Major differences in spring precipitation between the 2 years of our study were associated with differences in reproductive rates and, in some species, with numbers of juveniles captured. Reduced reproductive effort during spring drought will have a greater impact on bat populations with the forecasted increase in aridity in much of western North America by models of global climate change. We radiotracked 46 bats of 5 species to roosts and describe the first-known maternity colonies of spotted bats (Euderma maculatum) in Colorado. All 5 species that we tracked to diurnal roosts relied almost exclusively on rock crevices rather than trees or snags, despite the presence of mature forests at Mesa Verde and the use of trees for roosts in similar forests elsewhere by some of these species. Comparisons with past bat surveys at Mesa Verde and in surrounding areas suggest no dramatic evidence for effects of recent stand-replacing fires on the composition of the bat community.

  6. Preliminary Ambient Noise and Seismic Interferometry Analysis of the Laguna del Maule Volcanic Field, Chile

    NASA Astrophysics Data System (ADS)

    Wespestad, C.; Thurber, C. H.; Bennington, N. L.; Zeng, X.; Cardona, C.; Keranen, K. M.; Singer, B. S.

    2015-12-01

    Laguna del Maule Volcanic Field is a large, restless, youthful rhyolitic system in the Southern Andes of Chile. We present a preliminary examination of ambient noise data at this site from 12 University of Wisconsin and 6 OVDAS (Southern Andean Volcano Observatory) broadband seismometers for a 3 month period. Ambient noise tomography seeks to correlate pairs of stations, with one station acting as a virtual source and the other a receiver, generating empirical Green's functions between each pair. The noise correlation functions (NCFs) were computed for day-long and hour-long windows, then the final NCFs were obtained from stacking each time window set. The hour-long NCFs converged more rapidly, so this time window was chosen for use in later stages. This study used phase weighted stacking of the NCFs instead of linear stacking in order to achieve a better signal to noise ratio (SNR), although linearly stacked Green's functions were also created to confirm the improvement. Phase weighted stacking can detect signals with weak amplitudes much more clearly than linear stacking by finding coherence of signals in multiple frequency bins and down-weighting the importance of amplitude for correlation (Schimmel and Gallart, 2007). The Frequency-Time Analysis Technique was utilized to measure group velocity, and initial results show it to be about 2 km/s on average. Fluctuations of the average velocity between different station pairs across this dense array will provide a preliminary indication of the location and size of the magma system. This study also applied seismic interferometry using ambient noise to determine temporal changes in seismic velocity occurring at Laguna del Maule. Initial results show temporal changes in seismic velocity correlated to seasonal changes in the hydrologic cycle (rain, snow pack, snow melt, etc.). Current work focuses on identifying changes in seismic velocity associated with ongoing volcanic processes.

  7. Looking for Biosignatures in Carbonate Microbialites from the Laguna Negra, Argentinian Andes

    NASA Astrophysics Data System (ADS)

    Boidi, F. J.; Gomez, F. J.; Fike, D. A.; Bradley, A. S.; Farías, M. E.; Beeler, S.

    2015-12-01

    The distinction between biotic and abiotic control on microbialites formation and its signatures is relevant since stromatolites are considered the oldest evidence for life on Earth and a target for astrobiological research. The Laguna Negra is a shallow hypersaline lake placed at the Andes, Northwest Argentina, where carbonate microbialites and microbial mats develop. It is a unique system where microbial influence on carbonate precipitation and potential preserved biosignatures in the microbialites can be studied. Here we compare three distinct microbialites systems: carbonate laminar crusts with no visible microbial mats, stromatolites and dm-size oncoids, both related with different microbial mats. Our goal is to unravel the biotic controls on their formation, and the biosignatures there recorded. Laminar crusts are composed of stacked regular and isopachous carbonate lamina. Oncoids laminae are typically characterized by irregular hybrid micro-textures, composed of alternating micritic and botryoidal laminae, and the stromatolites are mostly composed by irregular micritic laminae. Sulfur isotopes of carbonate associated sulphate show similar values but they show differences in the pyrite sulfur isotopes suggesting differences in the fractionation degree, possibly related to sulphate reducing bacteria and variable sulphate reservoirs in the case of stromatolites and oncoids. δ13C fractionation between organic carbon and carbonates suggests photosynthesis, but other metabolisms cannot yet be discarded. 16S rDNA data of the microbial communities associated with the carbonate structures indicate the presence of these taxonomic groups and those that are known to influence carbonate precipitation, particularly in the stromatolites associated microbial community. Our data indicate significant differences between the three systems in terms of stable isotopes, textures and associated microbial diversity, suggesting a microbial control on stromatolites and oncoids

  8. Foraminifera Assemblages in Laguna Torrecilla- Puerto Rico: an Environmental Micropaleontology Approach.

    NASA Astrophysics Data System (ADS)

    Martinez-Colon, M.; Hallock, P.

    2006-12-01

    Foraminiferal assemblages (Ammonia becarii cf. typica - A. becarii cf. tepida - Triloculina spp.) from 30 cm cores taken at Laguna Torrecilla, a polluted estuary, contain a relative high occurrence of deformed tests (up to 13%). Such deformities (i.e., double tests, aberrant tests) are mostly found within the miliolids (Triloculina spp.) while the rotaliids (Ammonia spp.) show fewer deformities (i.e., extended proloculi, stunted tests). Preliminary results for heavy metal analysis (ACTLABS Laboratories-Canada) from bulk sediment samples show concentrations below toxicity levels except for copper. Copper concentrations (50- 138 ppm) fall between the ERL (Effect Range Low) and ERM (Effect Range Median) values representing possible to occasional detrimental effects to the aquatic environment. Organic matter content (loss-on-ignition) ranging from 10-23%, coupled with pyritized tests and framboidal pyrite, indicates low oxygen conditions. Ammonia becarii cf. typica and A. becarii cf. tepida showed no significant variation in size with sample depth. However, forma tepida was not found in the intervals with highest organic concentrations. The abundance of A. becarii, which is a species highly resistant to environmental stresses, appears to be related to hypoxia events. Ammonia-Elphidium index values, a previously established indicator of hypoxia, are 80-100, reflecting the lack of Elphidium spp. Apparently reduced oxygen conditions at Laguna Torrecilla exceeded the tolerance levels of Elphidium spp. In addition, diversity indices show that there has been temporal variability in terms of abundance and distribution of foraminifera. Foraminiferal assemblages coupled with diversity indices and organic matter content indicates that Torrecilla Lagoon has undergone several episodes of hypoxia. Such conditions could explain the relatively high percentage of test deformities, although elevated copper concentrations may be a compounding factor.

  9. FOGO-2014: Monitoring the Fogo 2014 Eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Fernandes, Rui; Faria, Bruno

    2015-04-01

    Fogo volcano, located in the Cape Verde Archipelago offshore Western Africa, is a complete stratovolcano system that was created by the Cape Verde hotspot, forming the island of Fogo. The top (Pico do Fogo) reaches ~2830m above sea level, and raises ~1100m above Chã das Caldeiras, an almost flat circular area with approximately 10 kilometres in the north-south direction and 7 kilometres in the east-west direction. Chã das Caldeiras, surrounded towards the West by the ~1000m high Bordeira rampart, has been inhabited since the early 20th Century, because it is one of the most productive agricultural areas in this semi-arid country. Fogo volcano erupted on November 23, 2014 (~10:00UTC) on a subsidiary vent of the main cone, after 19 years of inactivity. C4G (Collaboratory for Geosciences), a distributed research infrastructure created in 2014 in the framework of the Portuguese Roadmap for Strategic Research Infrastructures, immediately offered support to the Cape Verdean authorities, with the goal of complementing the permanent geophysical monitoring network operated in Fogo island by INMG, the Cape Verdean Meteorological and Geophysical Institute. This permanent network is composed of seven seismographic stations and three tiltmeter stations, and the data is transmitted in real time to the INMG geophysical laboratory in São Vicente Island, where it is analysed on a routine basis. Pre-eruptive activity started to be detected by the permanent monitoring network on October 2014, with earthquakes occurring at depths larger than 15 km. These events led to a first volcanic warning to the Cape Verdean Civil Protection Agency. On November 22 several volcano-tectonic earthquakes were recorded at shallow depths, indicating shallow fracturing. On the basis of this activity, INMG issued a formal alert of an impending eruption to the Civil Protection Agency, ~24 hours before the onset of the eruption. Volcanic tremor and clear tiltmeter signals were recorded about one hour

  10. Implementacion de modulos constructivistas que atiendan "misconceptions" y lagunas conceptuales en temas de la fisica en estudiantes universitarios

    NASA Astrophysics Data System (ADS)

    Santacruz Sarmiento, Neida M.

    Este estudio se enfoco en los "misconception" y lagunas conceptuales en temas fundamentales de Fisica como son Equilibrio Termodinamico y Estatica de fluidos. En primer lugar se trabajo con la identificacion de "misconceptions" y lagunas conceptuales y se analizo en detalle la forma en que los estudiantes construyen sus propias teorias de fenomenos relacionados con los temas. Debido a la complejidad en la que los estudiantes asimilan los conceptos fisicos, se utilizo el metodo de investigacion mixto de tipo secuencial explicativo en dos etapas, una cuantitativa y otra cualitativa. La primera etapa comprendio cuatro fases: (1) Aplicacion de una prueba diagnostica para identificar el conocimiento previo y lagunas conceptuales. (2) Identificacion de "misconceptions" y lagunas del concepto a partir del conocimiento previo. (3) Implementacion de la intervencion por medio de modulos en el topico de Equilibrio Termodinamico y Estatica de Fluidos. (4) Y la realizacion de la pos prueba para analizar el impacto y la efectividad de la intervencion constructivista. En la segunda etapa se utilizo el metodo de investigacion cualitativo, por medio de una entrevista semiestructurada que partio de la elaboracion de un mapa conceptual y se finalizo con un analisis de datos conjuntamente. El desarrollo de este estudio permitio encontrar "misconceptions" y lagunas conceptuales a partir del conocimiento previo de los estudiantes participantes en los temas trabajados, que fueron atendidos en el desarrollo de las distintas actividades inquisitivas que se presentaron en el modulo constructivista. Se encontro marcadas diferencias entre la pre y pos prueba en los temas, esto se debio al requerimiento de habilidades abstractas para el tema de Estatica de Fluidos y al desarrollo intuitivo para el tema de Equilibrio Termodinamico, teniendo mejores respuestas en el segundo. Los participantes demostraron una marcada evolucion y/o cambio en sus estructuras de pensamiento, las pruebas estadisticas

  11. The apid cuckoo bees of the Cape Verde Islands (Hymenoptera, Apidae)

    PubMed Central

    Straka, Jakub; Engel, Michael S.

    2012-01-01

    Abstract The apid cuckoo bees of the Cape Verde Islands (Republic of Cape Verde) are reviewed and five species recognized, representing two genera. The ammobatine genus Chiasmognathus Engel (Nomadinae: Ammobatini), a specialized lineage of cleptoparasites of nomioidine bees is recorded for the first time. Chiasmognathus batelkai sp. n. is distinguished from mainland African and Asian species. The genus Thyreus Panzer (Apinae: Melectini) is represented by four species – Thyreus denolii sp. n., Thyreus batelkai sp. n., Thyreus schwarzi sp. n., and Thyreus aistleitneri sp. n. Previous records of Thyreus scutellaris (Fabricius) from the islands were based on misidentifications. PMID:22977347

  12. Geological setting and paleomagnetism of the Eocene red beds of Laguna Brava Formation (Quebrada Santo Domingo, northwestern Argentina)

    NASA Astrophysics Data System (ADS)

    Vizán, H.; Geuna, S.; Melchor, R.; Bellosi, E. S.; Lagorio, S. L.; Vásquez, C.; Japas, M. S.; Ré, G.; Do Campo, M.

    2013-01-01

    The red bed succession cropping out in the Quebrada Santo Domingo in northwestern Argentina had been for long considered as Upper Triassic-Lower Jurassic in age based on weak radiometric and paleontological evidence. Preliminary paleomagnetic data confirmed the age and opened questions about the nature of fossil footprints with avian features discovered in the section. Recently the stratigraphic scheme was reviewed with the identification of previously unrecognized discontinuities, and a radiometric dating obtained in a tuff, indicated an Eocene age for the Laguna Brava Formation and the fossil bird footprints, much younger than the previously assigned. We present a detailed paleomagnetic study interpreted within a regional tectonic and stratigraphic framework, looking for an explanation for the misinterpretation of the preliminary paleomagnetic data. The characteristic remanent magnetizations pass a tilt test and a reversal test. The main magnetic carrier is interpreted to be low Ti titanomagnetites and to a lesser extent hematite. The characteristic remanent magnetization would be essentially detrital. The obtained paleomagnetic pole (PP) for the Laguna Brava Formation has the following geographic coordinates and statistical parameters: N = 29, Lon. = 184.5° E, Lat. = 75.0° S, A95 = 5.6° and K = 23.7. When this PP is compared with another one with similar age obtained in an undeformed area, a declination anomaly is recognized. This anomaly can be interpreted as Laguna Brava Formation belonging to a structural block that rotated about 16° clockwise along a vertical axis after about 34 Ma. This block rotation is consistent with the regional tectonic framework, and would have caused the fortuitous coincidence of the PP with Early Jurassic poles. According to the interpreted magnetostratigraphic correlation, the Laguna Brava Formation would have been deposited during the Late Eocene with a mean sedimentation rate of about 1.4 cm per thousand years, probably in

  13. Recent Science from the Cape Verde Atmospheric Observatory (CVAO)

    NASA Astrophysics Data System (ADS)

    Read, Katie; Lee, James; Punjabi, Shalini; Carpenter, Lucy; Lewis, Alastair; Moller, Sarah; Mendes Neves, Luis; Fleming, Zoe; Evans, Mat; Arnold, Steve; Hopkins, James

    2013-04-01

    The Cape Verde Atmospheric Observatory (16,848°N, 24.871°W), a subtropical marine boundary layer atmospheric monitoring station situated at Calhau on the island of São Vicente, has been in operation since October 2006. Almost continuous measurements of the trace gases O3, CO, NMVOC, NO, and NO2 have been obtained. Other data from the CVAO, for example of greenhouse gases, aerosol (physical and chemical parameters), halocarbons, halogen oxides, are also available over various timescales (see http://ncasweb.leeds.ac.uk/capeverde/ for more details). Through the newly EU funded Global Mercury Observation System (GMOS) project, atmospheric measurements of mercury began in 2011. The observatory has hosted a number of field campaigns including Reactive Halogens in the Marine Boundary Layer experiment (RHaMBLe) in 2007 (Lee et al., 2010) which focussed on halogen chemistry and Seasonal Oxidant Study (SOS) in 2009 which looked at how the oxidation chemistry varied seasonally. The prevailing strong on-shore winds bring marine air masses with varying inputs of Saharan dust and of long range transport from North American Europe, thus the CVAO is an appealing location for both short and long term research into a variety of atmospheric phenomena. Aged air masses from North America, Europe, and Africa influence the measurements at the observatory, but fresh emissions from coastal Africa and the ocean may also play a major role. Through the use of the UK Met office's NAME model (http://www.metoffice.gov.uk/research/modelling-systems/dispersion-model) it has recently been possible to classify the air received by the site and this has since been employed in further interpretation of the datasets (Carpenter et al., 2010). Measurements from the last six years will be presented at the conference together with comparisons with the output of the CAM-Chem global chemistry transport model (Read et al., 2012). The CVAO is a global GAW (Global Atmospheric Watch) station and so data is

  14. Ancient mortars from Cape Verde: mineralogical and physical characterization

    NASA Astrophysics Data System (ADS)

    Rocha, Fernando; Costa, Cristiana; Velosa, Ana; Quintela, Ana; Terroso, Denise; Marques, Vera

    2014-05-01

    Times and locations of different building constructions means different knowledge, habits, different construction methods and materials. The study and safeguarding of the architectural heritage takes nowadays a progressive importance as a vehicle for transmission of cultures and history of nations. The coatings are of great importance in the durability of a building due to the protective role of the masonry. The compatibility between the materials with which they are executed (masonry, mortar and grout settlement) promotes the proper functioning of the wall and a consequent increase in durability. Therefore, it becomes important to study and characterize the mortar coating of buildings to know its characteristics and to use compatible materials in the rehabilitation and maintenance of buildings. This study aims to characterize the chemical, physical, mechanical and mineralogical mortar samples collected in buildings in three islands of Cape Verde, for the conservation, rehabilitation and preservation of them. The collected samples belong to buildings constructed in the end of XIX century and in the beginning of XX century. In order to characterize the mortar samples some tests was made, such as X-Ray Diffraction, X- Ray Fluorescence, acid attack and mechanical strength. The samples were divided into three groups depending on origin; so we have a first group collected on the island of Santiago, the second on the island of Saint Vincent and the third on the island of Santo Antao. The samples are all carbonated, but Santiago samples have a lower carbonates content. In terms of insoluble residue (from the acid attack) it was concluded that the samples have similar value ranging from 9 to 26%. The compressive strength of the mortars have a range between 1.36 and 4.55 MPa, which is related to the presence of more binder in samples with higher resistance. The chemical and mineralogical analyzes showed that these consist of lime mortars (binder), natural pozzolan and

  15. Unusual Volcanic Tremor Observations in Fogo Island, Cape Verde

    NASA Astrophysics Data System (ADS)

    Custodio, S. I.; Heleno, S. I.

    2004-12-01

    Volcanic tremor is a ground motion characterized by well-defined frequencies, and has traditionally been explained by the movement of fluids, namely magma, in conduits or cracks (Chouet, 1996). Thus tremor has the potential to reveal key aspects of volcanic structure and dynamics. Two types of previously unreported seismic signals have been observed in Fogo volcano: a) tide-modulated seismic noise and volcanic tremor, and b) high-frequency low-attenuation harmonic tremor. Amplitude modulation of seismic noise can be detected by simple eye-inspection of raw data in some stations of the VIGIL Network, Fogo Volcano. A more detailed analysis shows that certain frequency bands which we interpret as volcanic tremor, mainly in the range 2.0-3.0Hz, are preferentially modulated. The main frequency of modulation is 1.93 c.p.d., which corresponds to M2, the semi-diurnal lunar harmonic. Air pressure and temperature, which are continuously monitored in Fogo Island, have been analyzed and cannot explain the observed periodicity. Thus we conclude that seismic noise and tremor amplitudes are controlled by tides (Custodio et al., 2003). A relation between the tidal modulation and hydrothermal systems activity is suspected and under investigation. High-frequency (HF) tremor (5-20 Hz) has been recorded simultaneously in several stations in Fogo Island and even in different islands of the Cape Verde archipelago (up to distances of 120 km). In volcanic environments high-frequency motions are normally recorded in a small area close to the source, due to the strong attenuation of seismic waves. Non-volcanic origins for HF tremor were examined: cultural noise, whale vocalizations, ship noise, electronic/processing artifacts and path and/or site effects were all considered and dismissed. Emergent arrivals and strong site effects render source location a difficult task, but the analysis of wave polarizations and amplitude distributions seems to point to an offshore source. Two alternative

  16. Monitoring Fogo Island, Cape Verde Archipelago, for Volcanic Hazard Mitigation

    NASA Astrophysics Data System (ADS)

    Faria, B. V.; Heleno, S. I.; Barros, I. J.; d'Oreye, N.; Bandomo, Z.; Fonseca, J. F.

    2001-12-01

    Fogo Island, in the Cape Verde Archipelago (North Atlantic), with a total area of 476 km2 and a population of about 40000, is an active ocean island volcano raising from an average sea-bottom depth of the order of -3000m to a maximum altitude of 2820m. All of the 28 historically recorded eruptions (Ribeiro, 1960) since the arrival of the first settlers in the 15th Century took place in Cha das Caldeiras, a 9 km-wide flat zone 1700 meters above sea level that resulted from the infill of a large lateral collapse caldera (Day et al., 2000). The last eruptions occurred in 1951 and 1995, through secondary cones at the basis of Pico do Fogo, the main volcanic edifice. A tall scarp surrounds Cha das Calderas on its western side only, and the eastern limit leads to a very steep sub-aerial slope down to the coastline. With this morphology, the volcanic hazard is significant inside Cha das Caldeiras - with a resident population of the order of 800 - and particularly in the villages of the eastern coast. Because the magma has low viscosity, eruptions in Fogo have scarce precursory activity, and its forecast is therefore challenging. The VIGIL monitoring network was installed between 1997 and 2001, and is currently in full operation. It consists of seven seismographic stations - two of which broadband - four tilt stations, a CO2 monitoring station and a meteo station. The data is telemetred in real time to the central laboratory in the neighbor island of Santiago, and analyzed on a daily basis. The continuous data acquisition is complemented by periodic GPS, gravity and leveling surveys (Lima et al., this conference). In this paper we present the methodology adopted to monitor the level of volcanic activity of Fogo Volcano, and show examples of the data being collected. Anomalous data recorded at the end of September 2000, which led to the only occurrence of an alert warning so far, are also presented and discussed.

  17. Sediment transport on the Palos Verdes shelf, California

    NASA Astrophysics Data System (ADS)

    Ferré, Bénédicte; Sherwood, Christopher R.; Wiberg, Patricia L.

    2010-04-01

    Sediment transport and the potential for erosion or deposition have been investigated on the Palos Verdes (PV) and San Pedro shelves in southern California to help assess the fate of an effluent-affected deposit contaminated with DDT and PCBs. Bottom boundary layer measurements at two 60-m sites in spring 2004 were used to set model parameters and evaluate a one-dimensional (vertical) model of local, steady-state resuspension, and suspended-sediment transport. The model demonstrated skill (Brier scores up to 0.75) reproducing the magnitudes of bottom shear stress, current speeds, and suspended-sediment concentrations measured during an April transport event, but the model tended to underpredict observed rotation in the bottom-boundary layer, possibly because the model did not account for the effects of temperature-salinity stratification. The model was run with wave input estimated from a nearby buoy and current input from four to six years of measurements at thirteen sites on the 35- and 65-m isobaths on the PV and San Pedro shelves. Sediment characteristics and erodibility were based on gentle wet-sieve analysis and erosion-chamber measurements. Modeled flow and sediment transport were mostly alongshelf toward the northwest on the PV shelf with a significant offshore component. The 95th percentile of bottom shear stresses ranged from 0.09 to 0.16 Pa at the 65-m sites, and the lowest values were in the middle of the PV shelf, near the Whites Point sewage outfalls where the effluent-affected layer is thickest. Long-term mean transport rates varied from 0.9 to 4.8 metric tons m -1 yr -1 along the 65-m isobaths on the PV shelf, and were much higher at the 35-m sites. Gradients in modeled alongshore transport rates suggest that, in the absence of a supply of sediment from the outfalls or PV coast, erosion at rates of ˜0.2 mm yr -1 might occur in the region southeast of the outfalls. These rates are small compared to some estimates of background natural sedimentation

  18. PILOT IN SITU CAPPING PROJECT FOR PALOS VERDES SHELF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    The Palos Verdes Shelf Pilot Capping Project will evaluate the short-term results of capping the DDT- and PCB-contaminated sediment with clean sediment. It will also determine how these results are affected by variables such as cap material, placement method and water depth. The ...

  19. Lotus alianus, a new species from Cabo Verde and nomeenclatural notes on Lotus section Pedrosia (Fabaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lotus alianus J.H. Kirkbr., sp. nov., is described and illustrated. It is a rare endemic species from the Republic of Cape Verde, and is found in dry habitats on just two islands, Ilhas de Santo Antao and Sao Vicente. In addition, two species names are synonymized with L. creticus L., and a lectotyp...

  20. Distribution of HLA alleles in Portugal and Cabo Verde. Relationships with the slave trade route.

    PubMed

    Spínola, H; Brehm, A; Williams, F; Jesus, J; Middleton, D

    2002-07-01

    HLA-A, -B, and -DR frequencies were analysed in populations from Portugal and the Madeira and Cabo Verde Archipelagos, aiming to characterize their genetic composition. Portuguese settlers colonized both Archipelagos in the 15th and 16th centuries. Madeira received many sub-Saharan slaves to work in the sugar plantations, and Cabo Verde served as a pivotal market in the Atlantic slave trade and was populated by individuals coming from the Senegambia region of the West African coast. The population of Madeira shows the highest genetic diversity and the presence of alleles and haplotypes usually linked to sub-Saharan populations, the haplotypes accounting for 3.5% of the total. Cabo Verde presents typical markers acknowledged to be of European or Ibero-Mediterranean origin, thus revealing the admixture of European settlers with Sub-Saharan slaves. Altogether the number of European haplotypes reaches 15% of the total. The Portuguese population shows a perceivable and significant heterogeneity both in allele and haplotype frequencies, unveiling a differential input of peoples from different origins. A PCA of the populations studied, plus other relevant ones, clearly shows gene heterogeneity in mainland Portugal as well as the differences and relationships between these populations and Madeira and Cabo Verde. PMID:12418969

  1. Five years of hanseniasis control activities in the Cape Verde Islands based on the OMSLEP system.

    PubMed

    Loretti, A

    1985-01-01

    After some general information about the use of the OMSLEP System in the National Hanseniasis Control Program of the Republic of Cape Verde the author presents some operational and epidemiological indices produced by the System, adding a short evaluation of the Program and of the use of the System. PMID:3880311

  2. Assessment of tight-gas resources in Canyon sandstones of the Val Verde Basin, Texas, 2016

    USGS Publications Warehouse

    Schenk, Christopher J.; Tennyson, Marilyn E.; Klett, Timothy R.; Mercier, Tracey J.; Brownfield, Michael E.; Gaswirth, Stephanie B.; Hawkins, Sarah J.; Leathers-Miller, Heidi M.; Marra, Kristen R.; Finn, Thomas M.; Pitman, Janet K.

    2016-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey assessed mean resources of 5 trillion cubic feet of gas and 187 million barrels of natural gas liquids in tight-gas assessment units in the Canyon sandstones of the Val Verde Basin, Texas.

  3. Promoting Distance Education in Higher Education in Cape Verde and Mozambique

    ERIC Educational Resources Information Center

    Ramos, Fernando; Taju, Gulamo; Canuto, Louisette

    2011-01-01

    Over the past six years, the authors have been project leaders for three distance education initiatives in Cape Verde and Mozambique: (1) a blended learning master's degree in multimedia in education for faculty in Cape Verdean public higher education institutions (2005-2008); (2) a teacher training programme for 1375 elementary teachers provided…

  4. Mesa Verde: A Study of Man in an Agricultural Setting. Student Manual.

    ERIC Educational Resources Information Center

    Community Health Service (DHEW/PHS), Bethesda, MD.

    This student manual contains information and guides to assist the secondary student in functioning as an archeologist. Included are fables, pictures for analysis, a time line and description of the pre-history of Mesa Verde, Colorado. The manual concludes with artifact identification word sheets. A related document is ED 001 722. (AWW)

  5. Immigration and Resiliency: Unpacking the Experiences of High School Students from Cape Verde and Ethiopia

    ERIC Educational Resources Information Center

    Hersi, Afra Ahmed

    2011-01-01

    This article explores the complex factors, both individual and social, that contribute to the resiliency and academic achievement of six adolescent African immigrant students from Cape Verde and Ethiopia who were enrolled in a small high school in the United States. The school was designed specifically for recent adolescent immigrant students.…

  6. Environmental Education Evaluation at the School: An Example in Sao Nicolau Island, Cape Verde

    ERIC Educational Resources Information Center

    Graziani, Pietro; Cabral, Daniel; Santana, Nelson

    2013-01-01

    Monte Gordo Natural Park (MGNP) is part of the Cape Verde (CV) Protected Areas National Network. In order to create an effective Environmental Education (EE) curriculum, it is crucial to first identify the level of environmental knowledge of both teachers and students. In 2007 we implemented a set of four surveys to students and educators and…

  7. Waterbirds (other than Laridae) nesting in the middle section of Laguna Cuyutlán, Colima, México.

    PubMed

    Mellink, Eric; Riojas-López, Mónica E

    2008-03-01

    Laguna de Cuyutlán, in the state of Colima, Mexico, is the only large coastal wetland in a span of roughly 1150 km. Despite this, the study of its birds has been largely neglected. Between 2003 and 2006 we assessed the waterbirds nesting in the middle portion of Laguna Cuyutlán, a large tropical coastal lagoon, through field visits. We documented the nesting of 15 species of non-Laridae waterbirds: Neotropic Cormorant (Phalacrocorax brasilianus), Tricolored Egret (Egretta tricolor), Snowy Egret (Egretta thula), Little Blue Heron (Egretta caerulea), Great Egret (Ardea alba), Cattle Egret (Bubulcus ibis), Black-crowned Night-heron (Nycticorax nycticorax), Yellow-crowned Night-heron (Nyctanassa violacea), Green Heron (Butorides virescens), Roseate Spoonbill (Platalea ajaja), White Ibis (Eudocimus albus), Black-bellied Whistling-duck (Dendrocygna autumnalis), Clapper Rail (Rallus longirostris), Snowy Plover (Charadrius alexandrinus), and Black-necked Stilt (Himantopus mexicanus). These add to six species of Laridae known to nest in that area: Laughing Gulls (Larus atricilla), Royal Terns (Thalasseus maximus), Gull-billed Terns (Gelochelidon nilotica), Forster's Terns (S. forsteri), Least Terns (Sternula antillarum), and Black Skimmer (Rynchops niger), and to at least 57 species using it during the non-breeding season. With such bird assemblages, Laguna Cuyutlán is an important site for waterbirds, which should be given conservation status. PMID:18624252

  8. A 6000-year record of ecological and hydrological changes from Laguna de la Leche, north coastal Cuba

    NASA Astrophysics Data System (ADS)

    Peros, Matthew C.; Reinhardt, Eduard G.; Davis, Anthony M.

    2007-01-01

    Laguna de la Leche, north coastal Cuba, is a shallow (≤ 3 m), oligohaline (˜ 2.0-4.5‰) coastal lake surrounded by mangroves and cattail stands. A 227-cm core was studied using loss-on-ignition, pollen, calcareous microfossils, and plant macrofossils. From ˜6200 to ˜ 4800 cal yr BP, the area was an oligohaline lake. The period from ˜ 4800 to ˜ 4200 cal yr BP saw higher water levels and a freshened system; these changes are indicated by an increase in the regional pollen rain, as well as by the presence of charophyte oogonia and an increase in freshwater gastropods (Hydrobiidae). By ˜ 4000 cal yr BP, an open mesohaline lagoon had formed; an increase in salt-tolerant foraminifers suggests that water level increase was driven by relative sea level rise. The initiation of Laguna de la Leche correlates with a shift to wetter conditions as indicated in pollen records from the southeastern United States (e.g., Lake Tulane). This synchronicity suggests that sea level rise caused middle Holocene environmental change region-wide. Two other cores sampled from mangrove swamps in the vicinity of Laguna de la Leche indicate that a major expansion of mangroves was underway by ˜ 1700 cal yr BP.

  9. From introduced American weed to Cape Verde Islands endemic: the case of Solanum rigidum Lam. (Solanaceae, Solanum subgenus Leptostemonum).

    PubMed

    Knapp, Sandra; Vorontsova, Maria S

    2013-01-01

    A Solanum species long considered an American introduction to the Cape Verde Islands off the west coast of Africa is identified as Solanum rigidum, a member of the Eggplant clade of Old World spiny solanums (Solanum subgenus Leptostemonum) and is probably endemic to the Cape Verde Islands. Collections of this species from the Caribbean are likely to have been introduced from the Cape Verde Islands on slave ships. We discuss the complex nomenclatural history of this plant and provide a detailed description, illustration and distribution map. The preliminary conservation status of Solanum rigidum is Least Concern, but needs to be reassessed in light of its endemic rather than introduced status. PMID:24198710

  10. From introduced American weed to Cape Verde Islands endemic: the case of Solanum rigidum Lam. (Solanaceae, Solanum subgenus Leptostemonum)

    PubMed Central

    Knapp, Sandra; Vorontsova, Maria S.

    2013-01-01

    Abstract A Solanum species long considered an American introduction to the Cape Verde Islands off the west coast of Africa is identified as Solanum rigidum, a member of the Eggplant clade of Old World spiny solanums (Solanum subgenus Leptostemonum) and is probably endemic to the Cape Verde Islands. Collections of this species from the Caribbean are likely to have been introduced from the Cape Verde Islands on slave ships. We discuss the complex nomenclatural history of this plant and provide a detailed description, illustration and distribution map. The preliminary conservation status of Solanum rigidum is Least Concern, but needs to be reassessed in light of its endemic rather than introduced status. PMID:24198710

  11. Postglacial eruptive history of Laguna del Maule volcanic field in Chile, from fallout stratigraphy in Argentina

    NASA Astrophysics Data System (ADS)

    Fierstein, J.; Sruoga, P.; Amigo, A.; Elissondo, M.; Rosas, M.

    2012-12-01

    The Laguna del Maule (LdM) volcanic field, which surrounds the 54-km2 lake of that name, covers ~500 km2 of rugged glaciated terrain with Quaternary lavas and tuffs that extend for 40 km westward from the Argentine frontier and 30 km N-S from the Rio Campanario to Laguna Fea in the Southern Volcanic Zone of Chile. Geologic mapping (Hildreth et al., 2010) shows that at least 130 separate vents are part of the LdM field, from which >350 km3 of products have erupted since 1.5 Ma. These include a ring of 36 postglacial rhyolite and rhyodacite coulees and domes that erupted from 24 separate vents and encircle the lake, suggesting a continued large magma reservoir. Because the units are young, glassy, and do not overlap, only a few ages had been determined and the sequence of most of the postglacial eruptions had not previously been established. However, most of these postglacial silicic eruptions were accompanied by explosive eruptions of pumice and ash. Recent investigations downwind in Argentina are combining stratigraphy, grain-size analysis, chemistry, and radiocarbon dating to correlate the tephra with eruptive units mapped in Chile, assess fallout distribution, and establish a time-stratigraphic framework for the postglacial eruptions at Laguna del Maule. Two austral summer field seasons with a tri-country collaboration among the geological surveys of the U.S., Chile, and Argentina, have now established that a wide area east of the volcanic field was blanketed by at least 3 large explosive eruptions from LdM sources, and by at least 3 more modest, but still significant, eruptions. In addition, an ignimbrite from the LdM Barrancas vent complex on the border in the SE corner of the lake traveled at least 15 km from source and now makes up a pyroclastic mesa that is at least 40 m thick. This ignimbrite (72-75% SiO2) preceded a series of fall deposits that are correlated with eruption of several lava flows that built the Barrancas complex. Recent 14C dates suggest

  12. The offshore Palos Verdes fault zone near San Pedro, Southern California

    USGS Publications Warehouse

    Fisher, M.A.; Normark, W.R.; Langenheim, V.E.; Calvert, A.J.; Sliter, R.

    2004-01-01

    High-resolution seismic-reflection data are combined with a variety of other geophysical and geological data to interpret the offshore structure and earthquake hazards of the San Pedro shelf, near Los Angeles, California. Prominent structures investigated include the Wilmington graben, the Palos Verdes fault zone, various faults below the west part of the San Pedro shelf and slope, and the deep-water San Pedro basin. The structure of the Palos Verdes fault zone changes markedly along strike southeastward across the San Pedro shelf and slope. Under the north part of the shelf, this fault zone includes several strands, with the main strand dipping west. Under the slope, the main fault strands exhibit normal separation and mostly dip east. To the southeast near Lasuen Knoll, the Palos Verdes fault zone locally is low angle, but elsewhere near this knoll, the fault dips steeply. Fresh seafloor scarps near Lasuen Knoll indicate recent fault movement. We explain the observed structural variation along the Palos Verdes fault zone as the result of changes in strike and fault geometry along a master right-lateral strike-slip fault at depth. Complicated movement along this deep fault zone is suggested by the possible wave-cut terraces on Lasuen Knoll, which indicate subaerial exposure during the last sea level lowstand and subsequent subsidence of the knoll. Modeling of aeromagnetic data indicates a large magnetic body under the west part of the San Pedro shelf and upper slope. We interpret this body to be thick basalt of probable Miocene age. This basalt mass appears to have affected the pattern of rock deformation, perhaps because the basalt was more competent during deformation than the sedimentary rocks that encased the basalt. West of the Palos Verdes fault zone, other northwest-striking faults deform the outer shelf and slope. Evidence for recent movement along these faults is equivocal, because we lack age dates on deformed or offset sediment.

  13. Larvicidal activity against Aedes aegypti of Foeniculum vulgare essential oils from Portugal and Cape Verde.

    PubMed

    Rocha, Diara Kady; Matosc, Olivia; Novoa, Maria Teresa; Figueiredo, Ana Cristina; Delgado, Manuel; Moiteiro, Cristina

    2015-04-01

    Dengue is a potentially fatal mosquito-borne infection with 50 million cases per year and 2.5 billion people vulnerable to the disease. This major public health problem has recurrent epidemics in Latin America and occurred recently in Cape Verde and Madeira Island. The lack of anti-viral treatment or vaccine makes the control of mosquito vectors a high option to prevent virus transmission. Essential oil (EO) constituents can affect insect's behaviour, being potentially effective in pest control. The present study evaluated the potential use of Foenicultm vulgare (fennel) EO in the control of the dengue vector Aedes aegypti. EOs isolated from fennel aerial parts collected in Cape Verde and from a commercial fennel EO of Portugal were analysed by NMR, GC and GC-MS. trans-Anethole (32 and 30%, respectively), limonene (28 and 18%, respectively) and fenchone (10% in both cases) were the main compounds identified in the EOs isolated from fennel from Cape Verde and Portugal, respectively. The larvicidal activity of the EOs and its major constituents were evaluated, using WHO procedures, against third instar larvae ofAe. aegypti for 24 h. Pure compounds, such as limonene isomers, were also assayed. The lethal concentrations LC50, C90 and LC99 were determined by probit analysis using mortality rates of bioassays. A 99% mortality of Ae. aegypti larvae was estimated at 37.1 and 52.4 µL L-1 of fennel EOs from Cape Verde and Portugal, respectively. Bioassays showed that fennel EOs from both countries displayed strong larvicidal effect against Ae. aegypti, the Cape Verde EO being as active as one of its major constituents, (-)-limonene. PMID:25973508

  14. A 5000 Year Record of Andean South American Summer Monsoon Variability from Laguna de Ubaque, Colombia

    NASA Astrophysics Data System (ADS)

    Rudloff, O. M.; Bird, B. W.; Escobar, J.

    2014-12-01

    Our understanding of Northern Hemisphere South American summer monsoon (SASM) dynamics during the Holocene has been limited by the small number of terrestrial paleoclimate records from this region. In order to increase our knowledge of SASM variability and to better inform our predictions of its response to ongoing rapid climate change, we require high-resolution paleoclimate records from the Northern Hemisphere Andes. To this end, we present sub-decadally resolved sedimentological and geochemical data from Laguna de Ubaque that spans the last 5000 years. Located in the Eastern Cordillera of the Colombian Andes, Laguna de Ubaque (2070 m asl) is a small, east facing moraine-dammed lake in the upper part of the Rio Meta watershed near Bogotá containing finely laminated clastic sediments. Dry bulk density, %organic matter, %carbonate and magnetic susceptibility (MS) results from Ubaque suggest a period of intense precipitation between 3500 and 2000 years BP interrupted by a 300 yr dry interval centered at 2700 years BP. Following this event, generally drier conditions characterize the last 2000 years. Although considerably lower amplitude than the middle Holocene pluvial events, variability in the sedimentological data support climatic responses during the Medieval Climate Anomaly (MCA; 900 to 1200 CE) and Little Ice Age (LIA; 1450 to 1900 CE) that are consistent with other records of local Andean conditions. In particular, reduced MS during the MCA suggests a reduction in terrestrial material being washed into the lake as a result of generally drier conditions. The LIA on the other hand shows a two phase structure with increased MS between 1450 and 1600 CE, suggesting wetter conditions during the onset of the LIA, and reduced MS between 1600 and 1900 CE, suggesting a return to drier conditions during the latter part of the LIA. These LIA trends are similar to the Quelccaya accumulation record, possibly supporting an in-phase relationship between the South American

  15. The Maars of the Tuxtla Volcanic Field: the Example of 'laguna Pizatal'

    NASA Astrophysics Data System (ADS)

    Espindola, J.; Zamora-Camacho, A.; Hernandez-Cardona, A.; Alvarez del Castillo, E.; Godinez, M.

    2013-12-01

    Los Tuxtlas Volcanic Field (TVF), also known as Los Tuxtlas massif, is a structure of volcanic rocks rising conspicuously in the south-central part of the coastal plains of eastern Mexico. The TVF seems related to the upper cretaceous magmatism of the NW part of the Gulf's margin (e.g. San Carlos and Sierra de Tamaulipas alkaline complexes) rather than to the nearby Mexican Volcanic Belt. The volcanism in this field began in late Miocene and has continued in historical times, The TVF is composed of 4 large volcanoes (San Martin Tuxtla, San Martin Pajapan, Santa Marta, Cerro El Vigia), at least 365 volcanic cones and 43 maars. In this poster we present the distribution of the maars, their size and depths. These maars span from a few hundred km to almost 1 km in average diameter, and a few meters to several tens of meters in depth; most of them filled with lakes. As an example on the nature of these structures we present our results of the ongoing study of 'Laguna Pizatal or Pisatal' (18° 33'N, 95° 16.4'W, 428 masl) located some 3 km from the village of Reforma, on the western side of San Martin Tuxtla volcano. Laguna Pisatal is a maar some 500 meters in radius and a depth about 40 meters from the surrounding ground level. It is covered by a lake 200 m2 in extent fed by a spring discharging on its western side. We examined a succession of 15 layers on the margins of the maar, these layers are blast deposits of different sizes interbedded by surge deposits. Most of the contacts between layers are irregular; which suggests scouring during deposition of the upper beds. This in turn suggests that the layers were deposited in a rapid series of explosions, which mixed juvenile material with fragments of the preexisting bedrock. We were unable to find the extent of these deposits since the surrounding areas are nowadays sugar cane plantations and the lake has overspilled in several occassions.

  16. Impact of Diagenesis on Biosignature Preservation Potential in Playa Lake Evaporites of the Verde Formation, Arizona: Implications for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Shkolyar, S.; Farmer, J. D.

    2016-05-01

    We studied evaporite subfacies in the Verde Fmn., AZ. We identified diagenetic pathways and assessed how diagenesis affected biosignature preservation potential (BPP) in each. Results revealed eight pathways, each with diverse impacts on BPP.

  17. Stratigraphy and Characterization of Volcanic Deposits on the Northwestern Flanks of Mt. Makiling, Laguna, Philippines

    NASA Astrophysics Data System (ADS)

    Ybanez, R. L.; Bonus, A. A. B.; Judan, J. M.; Racoma, B. A.; Morante, K. A. M.; Balangue, M. I. R. D.

    2014-12-01

    Mt. Makiling is an inactive stratovolcano located in the province of Laguna. Semi-detailed geologic field mapping on the northwestern low-level flanks and apron of the volcano was conducted. Exposures reveal a volcanic terrain hosting a wide variety of volcanic rocks: lava flows, pyroclastic surges, pyroclastic flows, and tuff deposits. Stratigraphic logging of the volcanic deposits showed differences in occurrence of the deposit types as well as their characteristics. The pyroclastic flow deposits are found at the base of the column overlain by pyroclastic surges which were more common in the area. Capping the pyroclastic surges is a thin layer of tuffaceous units. Isolated deposits of lava flows of andesitic composition were mapped in the western flank of Mt. Makiling. These varying volcanic deposits are derived from different eruptive activities of Mt. Makiling, with at least three separate eruptive episodes indicated by the exposed deposits. Two separate explosive eruptions are marked by two different pyroclastic deposits, while an effusive episode, marked by andesitic lava flows, can also be identified. The pyroclastic surge deposit is uncharacteristically thick, around a hundred meters or more exposed, providing further questions as to the magnitude of past eruptions or the mechanism of pyroclastic material deposition around the volcano. Mt. Makiling, thus, has historically undergone different eruption types, but still releases generally the same material composition across varying deposits: intermediate or andesitic composition. This is consistent with the trend of Philippine volcanoes, and with the Macolod corridor which hosts this volcanic system.

  18. Impact of Water Resorts Development along Laguna de Bay on Groundwater Resources

    NASA Astrophysics Data System (ADS)

    Jago-on, K. A. B.; Reyes, Y. K.; Siringan, F. P.; Lloren, R. B.; Balangue, M. I. R. D.; Pena, M. A. Z.; Taniguchi, M.

    2014-12-01

    Rapid urbanization and land use changes in areas along Laguna de Bay, one of the largest freshwater lake in Southeast Asia, have resulted in increased economic activities and demand for groundwater resources from households, commerce and industries. One significant activity that can affect groundwater is the development of the water resorts industry, which includes hot springs spas. This study aims to determine the impact of the proliferation of these water resorts in Calamba and Los Banos, urban areas located at the southern coast of the lake on the groundwater as a resource. Calamba, being the "Hot Spring Capital of the Philippines", presently has more than 300 resorts, while Los Banos has at least 38 resorts. Results from an initial survey of resorts show that the swimming pools are drained/ changed on an average of 2-3 times a week or even daily during peak periods of tourist arrivals. This indicates a large demand on the groundwater. Monitoring of actual groundwater extraction is a challenge however, as most of these resorts operate without water use permits. The unrestrained exploitation of groundwater has resulted to drying up of older wells and decrease in hot spring water temperature. It is necessary to strengthen implementation of laws and policies, and enhance partnerships among government, private sector groups, civil society and communities to promote groundwater sustainability.

  19. Eocene plant diversity at Laguna del Hunco and Río Pichileufú, Patagonia, Argentina.

    PubMed

    Wilf, Peter; Johnson, Kirk R; Cúneo, N Rubén; Smith, M Elliot; Singer, Bradley S; Gandolfo, Maria A

    2005-06-01

    The origins of South America's exceptional plant diversity are poorly known from the fossil record. We report on unbiased quantitative collections of fossil floras from Laguna del Hunco (LH) and Río Pichileufú (RP) in Patagonia, Argentina. These sites represent a frost-free humid biome in South American middle latitudes of the globally warm Eocene. At LH, from 4,303 identified specimens, we recognize 186 species of plant organs and 152 species of leaves. Adjusted for sample size, the LH flora is more diverse than comparable Eocene floras known from other continents. The RP flora shares several taxa with LH and appears to be as rich, although sampling is preliminary. The two floras were previously considered coeval. However, (40)Ar/(39)Ar dating of three ash-fall tuff beds in close stratigraphic association with the RP flora indicates an age of 47.46+/-0.05 Ma, 4.5 million years younger than LH, for which one tuff is reanalyzed here as 51.91+/-0.22 Ma. Thus, diverse floral associations in Patagonia evolved by the Eocene, possibly in response to global warming, and were persistent and areally extensive. This suggests extraordinary richness at low latitudes via the latitudinal diversity gradient, corroborated by published palynological data from the Eocene of Colombia. PMID:15937744

  20. A geophysical and geological study of Laguna de Ayarza, a Guatemalan caldera lake

    USGS Publications Warehouse

    Poppe, L.J.; Paull, C.K.; Newhall, C.G.; Bradbury, J.P.; Ziagos, J.

    1985-01-01

    Geologic and geophysical data from Laguna de Ayarza, a figure-8-shaped doublecaldera lake in the Guatemalan highlands, show no evidence of postcaldera eruptive tectonic activity. The bathymetry of the lake has evolved as a result of sedimentary infilling. The western caldera is steep-sided and contains a large flat-floored central basin 240 m deep. The smaller, older, eastern caldera is mostly filled by coalescing delta fans and is connected with the larger caldera by means of a deep channel. Seismicreflection data indicate that at least 170 m of flat-lying unfaulted sediments partly fill the central basin and that the strata of the pre-eruption edifice have collapsed partly along inward-dipping ring faults and partly by more chaotic collapses. These sediments have accumulated in the last 23,000 years at a minimum average sedimentation rate of 7 m/103 yr. The upper 9 m of these sediments is composed of > 50% turbidites, interbedded with laminated clayey silts containing separate diatom and ash layers. The bottom sediments have >1% organic material, an average of 4% pyrite, and abundant biogenic gas, all of which demonstrate that the bottom sediments are anoxic. Although thin (<0.5 cm) ash horizons are common, only one thick (7-16 cm) primary ash horizon could be identified in piston cores. Alterations in the mineralogy and variations in the diatom assemblage suggest magnesium-rich hydrothermal activity. ?? 1985.

  1. Laguna Negra Virus Infection Causes Hantavirus Pulmonary Syndrome in Turkish Hamsters (Mesocricetus brandti).

    PubMed

    Hardcastle, K; Scott, D; Safronetz, D; Brining, D L; Ebihara, H; Feldmann, H; LaCasse, R A

    2016-01-01

    Laguna Negra virus (LNV) is a New World hantavirus associated with severe and often fatal cardiopulmonary disease in humans, known as hantavirus pulmonary syndrome (HPS). Five hamster species were evaluated for clinical and serologic responses following inoculation with 4 hantaviruses. Of the 5 hamster species, only Turkish hamsters infected with LNV demonstrated signs consistent with HPS and a fatality rate of 43%. Clinical manifestations in infected animals that succumbed to disease included severe and rapid onset of dyspnea, weight loss, leukopenia, and reduced thrombocyte numbers as compared to uninfected controls. Histopathologic examination revealed lung lesions that resemble the hallmarks of HPS in humans, including interstitial pneumonia and pulmonary edema, as well as generalized infection of endothelial cells and macrophages in major organ tissues. Histologic lesions corresponded to the presence of viral antigen in affected tissues. To date, there have been no small animal models available to study LNV infection and pathogenesis. The Turkish hamster model of LNV infection may be important in the study of LNV-induced HPS pathogenesis and development of disease treatment and prevention strategies. PMID:25722219

  2. The ambient acoustic environment in Laguna San Ignacio, Baja California Sur, Mexico.

    PubMed

    Seger, Kerri D; Thode, Aaron M; Swartz, Steven L; Urbán, Jorge R

    2015-11-01

    Each winter gray whales (Eschrichtius robustus) breed and calve in Laguna San Ignacio, Mexico, where a robust, yet regulated, whale-watching industry exists. Baseline acoustic environments in LSI's three zones were monitored between 2008 and 2013, in anticipation of a new road being paved that will potentially increase tourist activity to this relatively isolated location. These zones differ in levels of both gray whale usage and tourist activity. Ambient sound level distributions were computed in terms of percentiles of power spectral densities. While these distributions are consistent across years within each zone, inter-zone differences are substantial. The acoustic environment in the upper zone is dominated by snapping shrimp that display a crepuscular cycle. Snapping shrimp also affect the middle zone, but tourist boat transits contribute to noise distributions during daylight hours. The lower zone has three source contributors to its acoustic environment: snapping shrimp, boats, and croaker fish. As suggested from earlier studies, a 300 Hz noise minimum exists in both the middle and lower zones of the lagoon, but not in the upper zone. PMID:26627811

  3. Estimating floodplain sedimentation in the Laguna de Santa Rosa, Sonoma County, CA

    USGS Publications Warehouse

    Curtis, Jennifer A.; Flint, Lorraine E.; Hupp, Cliff R.

    2013-01-01

    We present a conceptual and analytical framework for predicting the spatial distribution of floodplain sedimentation for the Laguna de Santa Rosa, Sonoma County, CA. We assess the role of the floodplain as a sink for fine-grained sediment and investigate concerns regarding the potential loss of flood storage capacity due to historic sedimentation. We characterized the spatial distribution of sedimentation during a post-flood survey and developed a spatially distributed sediment deposition potential map that highlights zones of floodplain sedimentation. The sediment deposition potential map, built using raster files that describe the spatial distribution of relevant hydrologic and landscape variables, was calibrated using 2 years of measured overbank sedimentation data and verified using longer-term rates determined using dendrochronology. The calibrated floodplain deposition potential relation was used to estimate an average annual floodplain sedimentation rate (3.6 mm/year) for the ~11 km2 floodplain. This study documents the development of a conceptual model of overbank sedimentation, describes a methodology to estimate the potential for various parts of a floodplain complex to accumulate sediment over time, and provides estimates of short and long-term overbank sedimentation rates that can be used for ecosystem management and prioritization of restoration activities.

  4. Human factors engineering control-room-design review/audit report: Palo Verde Nuclear Generating Station, Arizona Public Service Company

    SciTech Connect

    Savage, J.W.; Lappa, D.A.

    1981-10-09

    A human factors engineering design review of the Palo Verde control room simulator was performed at the site on September 15 through September 17, 1981. Observed human factors design discrepancies were given priority ratings. This report summarizes the team's observations of the control room design and layout and of the control room operators' interface with the control room environment. A list of the human factors strengths observed in the Palo Verde control room simulator is given.

  5. X-chromosome STR markers data in a Cabo Verde immigrant population of Lisboa.

    PubMed

    Afonso Costa, Heloísa; Morais, Paulo; Vieira da Silva, Cláudia; Matos, Sara; Marques Santos, Rodolfo; Espinheira, Rosa; Costa Santos, Jorge; Amorim, António

    2014-01-01

    Population genetic data of 12 X chromosomal short tandem repeats markers (DXS10074, DXS10079, DXS10101, DXS10103, DXS10134, DXS10135, DXS10146, DXS10148, DXS7132, DXS7423, DXS8378 and HPRTB) were analysed in 54 females and 95 males of an immigrant population from Cabo Verde living in Lisboa. The obtained results for forensic statistical parameters such as observed heterozigosity, polymorphism information content, power of discrimination and mean exclusion chance, based on single allele frequencies, reveal that this multiplex system is highly informative and can represent an important tool for genetic identification purposes in the immigrant population of Cabo Verde. Since the studied short tandem repeats genetic markers are distributed on four linkage groups, that can provide independent genotype information, we studied those groups as haploytes. The forensic efficiency parameters for the linked groups were all higher than 0.97, with linkage group I being the most polymorphic and linkage group III the less informative. PMID:24474659

  6. Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Luecke, Andreas; Wissel, Holger; Mayr*, Christoph; Oehlerich, Markus; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

    2010-05-01

    The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok Aike and developed the environmental history of the semi-arid Patagonian steppe by a consequent interdisciplinary multi-proxy approach (e.g. Haberzettl et al., 2007). From September to November 2008 the ICDP deep drilling took place and successfully recovered in total 510 m of sediments from two sites resulting in a composite depth of 106 m for the selected main study Site 2. A preliminary age model places the record within the last 50.000 years. During the drilling campaign, the core catcher content of each drilled core run (3 m) was taken as separate sample to be shared and distributed between involved laboratories long before the main sampling party. A total of 70 core catcher samples describe the sediments of Site 2 and will form the base for more detailed investigations on the palaeoclimatic history of Patagonia. We here report on the organic carbon and nitrogen isotope composition of bulk sediment and plant debris of the core catcher samples. Similar investigations were performed for Holocene and Late Glacial sediments of Laguna Potrok Aike revealing insights into the organic matter dynamics of the lake and its catchment as well as into climatically induced hydrological variations with related lake level fluctuations (Mayr et al., 2009). The carbon and nitrogen content of the core catcher fine sediment fraction (<200 µm) is low to very low (around 1 % and 0.1 %, respectively) and requires particular attention in isotope analysis. The carbon isotope composition shows comparably little variation around a value of -26.0 per mil. The positive values of the Holocene and the Late

  7. Risk-based inservice testing program modifications at Palo Verde nuclear generating station

    SciTech Connect

    Knauf, S.; Lindenlaub, B.; Linthicum, R.

    1996-12-01

    Arizona Public Service Company (APS) is investigating changes to the Palo Verde Inservice Testing (IST) Program that are intended to result in the reduction of the required test frequency for various valves in the American Society of Mechanical Engineers (ASME) Section XI IST program. The analytical techniques employed to select candidate valves and to demonstrate that these frequency reductions are acceptable are risk based. The results of the Palo Verde probabilistic risk assessment (PRA), updated in June 1994, and the risk significant determination performed as part of the implementation efforts for 10 CFR 50.65 (the maintenance rule) were used to select candidate valves for extended test intervals. Additional component level evaluations were conducted by an `expert panel.` The decision to pursue these changes was facilitated by the ASME Risk-Based Inservice Testing Research Task Force for which Palo Verde is participating as a pilot plant. The NRC`s increasing acceptance of cost beneficial licensing actions and risk-based submittals also provided incentive to seek these changes. Arizona Public Service is pursuing the risk-based IST program modification in order to reduce the unnecessary regulatory burden of the IST program through qualitative and quantitative analysis consistent with maintaining a high level of plant safety. The objectives of this project at Palo Verde are as follows: (1) Apply risk-based technologies to IST components to determine their risk significance (i.e., high or low). (2) Apply a combination of deterministic and risk-based methods to determine appropriate testing requirements for IST components including improvement of testing methods and frequency intervals for high-risk significant components. (3) Apply risk-based technologies to high-risk significant components identified by the {open_quotes}expert panel{close_quotes} and outside of the IST program to determine whether additional testing requirements are appropriate.

  8. Patterns of genetic diversity in three plant lineages endemic to the Cape Verde Islands

    PubMed Central

    Romeiras, Maria M.; Monteiro, Filipa; Duarte, M. Cristina; Schaefer, Hanno; Carine, Mark

    2015-01-01

    Conservation of plant diversity on islands relies on a good knowledge of the taxonomy, distribution and genetic diversity of species. In recent decades, a combination of morphology- and DNA-based approaches has become the standard for investigating island plant lineages and this has led, in some cases, to the discovery of previously overlooked diversity, including ‘cryptic species’. The flora of the Cape Verde archipelago in the North Atlantic is currently thought to comprise ∼740 vascular plant species, 92 of them endemics. Despite the fact that it is considered relatively well known, there has been a 12 % increase in the number of endemics in the last two decades. Relatively few of the Cape Verde plant lineages have been included in genetic studies so far and little is known about the patterns of diversification in the archipelago. Here we present an updated list for the endemic Cape Verde flora and analyse diversity patterns for three endemic plant lineages (Cynanchum, Globularia and Umbilicus) based on one nuclear (ITS) and four plastid DNA regions. In all three lineages, we find genetic variation. In Cynanchum, we find two distinct haplotypes with no clear geographical pattern, possibly reflecting different ploidy levels. In Globularia and Umbilicus, differentiation is evident between populations from northern and southern islands. Isolation and drift resulting from the small and fragmented distributions, coupled with the significant distances separating the northern and southern islands, could explain this pattern. Overall, our study suggests that the diversity in the endemic vascular flora of Cape Verde is higher than previously thought and further work is necessary to characterize the flora. PMID:25979965

  9. Insecticide susceptibility of Aedes aegypti populations from Senegal and Cape Verde Archipelago

    PubMed Central

    2012-01-01

    Background Two concomitant dengue 3 (DEN-3) epidemics occurred in Cape Verde Archipelago and Senegal between September and October 2009. Aedes aegypti was identified as the vector of these epidemics as several DEN-3 virus strains were isolated from this species in both countries. The susceptibility to pyrethroids, organochlorine, organophosphates and carbamate was investigated in two field strains of Aedes aegypti from both countries using WHO diagnostic bioassay kits in order to monitor their the current status of insecticide susceptibility. Findings The two tested strains were highly resistant to DDT. The Cape Verde strain was found to be susceptible to all others tested insecticides except for propoxur 0.1%, which needs further investigation. The Dakar strain was susceptible to fenitrothion 1% and permethrin 0.75%, but displayed reduced susceptibility to deltamethrin, lambda-cyhalothrin and propoxur. Conclusions As base-line results, our observations stress a careful management of insecticide use for the control of Ae. aegypti. Indeed, they indicate that DDT is no longer efficient for the control of Ae. aegypti populations in Cape Verde and Dakar and further suggest a thorough follow-up of propoxur susceptibility status in both sites and that of deltamethrin and lambda-cyhalothrin in Ae. aegypti populations in Dakar. Thus, regular monitoring of susceptibility is greatly needed as well as the knowing if this observed resistance/susceptibility is focal or not and for observed resistance, the use of biochemical methods is needed with detailed comparison of resistance levels over a large geographic area. Keywords Aedes aegypti, Insecticides, Susceptibility, Cape Verde, Senegal PMID:23088621

  10. Patterns of genetic diversity in three plant lineages endemic to the Cape Verde Islands.

    PubMed

    Romeiras, Maria M; Monteiro, Filipa; Duarte, M Cristina; Schaefer, Hanno; Carine, Mark

    2015-01-01

    Conservation of plant diversity on islands relies on a good knowledge of the taxonomy, distribution and genetic diversity of species. In recent decades, a combination of morphology- and DNA-based approaches has become the standard for investigating island plant lineages and this has led, in some cases, to the discovery of previously overlooked diversity, including 'cryptic species'. The flora of the Cape Verde archipelago in the North Atlantic is currently thought to comprise ∼740 vascular plant species, 92 of them endemics. Despite the fact that it is considered relatively well known, there has been a 12 % increase in the number of endemics in the last two decades. Relatively few of the Cape Verde plant lineages have been included in genetic studies so far and little is known about the patterns of diversification in the archipelago. Here we present an updated list for the endemic Cape Verde flora and analyse diversity patterns for three endemic plant lineages (Cynanchum, Globularia and Umbilicus) based on one nuclear (ITS) and four plastid DNA regions. In all three lineages, we find genetic variation. In Cynanchum, we find two distinct haplotypes with no clear geographical pattern, possibly reflecting different ploidy levels. In Globularia and Umbilicus, differentiation is evident between populations from northern and southern islands. Isolation and drift resulting from the small and fragmented distributions, coupled with the significant distances separating the northern and southern islands, could explain this pattern. Overall, our study suggests that the diversity in the endemic vascular flora of Cape Verde is higher than previously thought and further work is necessary to characterize the flora. PMID:25979965

  11. Field reconnaissance of the effects of the earthquake of April 13, 1973, near Laguna de Arenal, Costa Rica

    USGS Publications Warehouse

    Plafker, George

    1973-01-01

    At about 3:34 a.m. on April 13, 1973, a moderate-sized, but widely-felt, earthquake caused extensive damage with loss of 23 lives in a rural area of about 150 km2 centered just south of Laguna de Arenal in northwestern Costa Rica (fig. 1). This report summarizes the results of the writer's reconnaissance investigation of the area that was affected by the earthquake of April 13, 1973. A 4-day field study of the meizoseismal area was carried out during the period from April 28 through May 1 under the auspices of the U.S. Geological Survey. The primary objective of this study was to evaluate geologic factors that contributed to the damage and loss of life. The earthquake was also of special interest because of the possibility that it was accompanied by surface faulting comparable to that which occurred at Managua, Nicaragua, during the disastrous earthquake of December 23, 1972 (Brown, Ward, and Plafker, 1973). Such earthquake-related surface faulting can provide scientifically valuable information on active tectonic processes at shallow depths within the Middle America arc. Also, identification of active faults in this area is of considerable practical importance because of the planned construction of a major hydroelectrical facility within the meizoseismal area by the Instituto Costarricense de Electricidad (I.C.E.). The project would involve creation of a storage reservoir within the Laguna de Arenal basin and part of the Río Arenal valley with a 75 m-high earthfill dam across Río Arenal at a point about 10 km east of the outlet of Laguna de Arenal.

  12. Microbiological quality of chicken- and pork-based street-vended foods from Taichung, Taiwan, and Laguna, Philippines.

    PubMed

    Manguiat, Lydia S; Fang, Tony J

    2013-10-01

    The microbiological quality of chicken- and pork-based street-food samples from Taichung, Taiwan's night markets (50) and Laguna, Philippines' public places (69) was evaluated in comparison to a microbiological guideline for ready-to-eat foods. Different bacterial contamination patterns were observed between 'hot-grilled' and 'cold cooked/fried' food types from the two sampling locations with 'hot grilled' foods generally showing better microbiological quality. Several samples were found to be unsatisfactory due to high levels of aerobic plate count, coliform, Escherichia coli, and Staphylococcus aureus. The highest counts obtained were 8.2 log cfu g⁻¹, 5.4 log cfu g⁻¹, 4.4 log cfu g⁻¹, and 3.9 log cfu g⁻¹, respectively, suggesting poor food hygiene practices and poor sanitation. Salmonella was found in 8% and 7% of Taichung and Laguna samples, respectively, which made the samples potentially hazardous. None of the samples was found to be positive for Listeria monocytogenes and E. coli O157, but Bacillus cereus was detected at the unsatisfactory level of 4 log cfu g⁻¹ in one Laguna sample. Antimicrobial resistance was observed for Salmonella, E. coli, and S. aureus isolates. Food preparation, cooking, and food handling practices were considered to be contributors to the unacceptable microbiological quality of the street foods. Hence, providing training on food hygiene for the street vendors should result in the improvement of the microbiological quality of street foods. The data obtained in this study can be used as input to microbial risk assessments and in identifying science-based interventions to control the hazards. PMID:23764220

  13. Origin and evolution of the Laguna Potrok Aike maar (Southern Patagonia, Argentina) as revealed by seismic data

    NASA Astrophysics Data System (ADS)

    Gebhardt, C.; de Batist, M. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2009-12-01

    Seismic reflection and refraction data provide insights into the sedimentary infill and the underlying volcanic structure of Laguna Potrok Aike, a maar lake situated in the Pali Aike Volcanic Field, Southern Patagonia. The lake has a diameter of ~3.5 km, a maximum water depth of ~100 m and a presumed age of ~770 ka. Its sedimentary regime is influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Multiproxy environmental reconstructions of the last 16 ka document that this terminal lake is highly sensitive to climate change. Laguna Potrok Aike has recently become a major focus of the International Continental Scientific Drilling Program and was drilled down to 100 m below lake floor in late 2008 within the PASADO project. The sediments are likely to contain a continental record spanning the last ca. 80 kyrs unique in the South American realm. Seismic reflection data show relatively undisturbed, stratified lacustrine sediments at least in the upper ~100 m of the sedimentary infill but are obscured possibly by gas and/or coarser material in larger areas. A model calculated from seismic refraction data reveals a funnel-shaped structure embedded in the sandstone rocks of the surrounding Santa Cruz Formation. This funnel structure is filled by lacustrine sediments of up to 370 m in thickness. These can be separated into two distinct subunits with low acoustic velocities of 1500-1800 m s-1 in the upper subunit pointing at unconsolidated lacustrine muds, and enhanced velocities of 2000-2350 m s-1 in the lower subunit. Below these lacustrine sediments, a unit of probably volcanoclastic origin is observed (>2400 m s-1). This sedimentary succession is well comparable to other well-studied sequences (e.g. Messel and Baruth maars, Germany), confirming phreatomagmatic maar explosions as the origin of Laguna Potrok Aike.

  14. Genetic differentiation of the Cabo Verde archipelago population analysed by STR polymorphisms.

    PubMed

    Fernandes, A T; Velosa, R; Jesus, J; Carracedo, A; Brehm, A

    2003-07-01

    Allele frequencies for 17 STR loci were analyzed in a sample of unrelated males from the Cabo Verde Archipelago. The samples were gathered in such a way that the origin of the subjects was perfectly identified, and they could be included in one of the leeward or windward groups of islands. This study reveals that there are significant differences between both groups of islands, and between Cabo Verdeans and other populations from sub-Sahara Africa including the Guineans, the most probable source population for Cabo Verdeans. This study confirms mtDNA data and, together with HLA and Y chromosome data already published, shows that the Cabo Verde population is sub-structured and atypical, diverging substantially from mainland sub-Saharan populations. Overall these differences are most probably due to admixture between sub-Saharan slaves brought into the islands and other settlers of European origin. In the absence of a clear indication of a different ethnic composition of the first sub-Saharan settlers of Cabo Verde, the differentiation exhibited in both groups of islands can be most probably be attributed to genetic drift. PMID:12914568

  15. Impact of Sahara dust transport on Cape Verde atmospheric element particles.

    PubMed

    Almeida-Silva, M; Almeida, S M; Freitas, M C; Pio, C A; Nunes, T; Cardoso, J

    2013-01-01

    The objectives of this study were to (1) conduct an elemental characterization of airborne particles sampled in Cape Verde and (2) assess the influence of Sahara desert on local suspended particles. Particulate matter (PM(10)) was collected in Praia city (14°94'N; 23°49'W) with a low-volume sampler in order to characterize its chemical composition by k0-INAA. The filter samples were first weighed and subsequently irradiated at the Portuguese Research Reactor. Results showed that PM(10) concentrations in Cape Verde markedly exceeded the health-based air quality standards defined by the European Union (EU), World Health Organization (WHO), and U.S. Environmental Protection Agency (EPA), in part due to the influence of Sahara dust transport. The PM(10) composition was characterized essentially by high concentrations of elements originating from the soil (K, Sm, Co, Fe, Sc, Rb, Cr, Ce, and Ba) and sea (Na), and low concentrations of anthropogenic elements (As, Zn, and Sb). In addition, the high concentrations of PM measured in Cape Verde suggest that health of the population may be less affected compared with other sites where PM(10) concentrations are lower but more enriched with toxic elements. PMID:23514066

  16. Improving Access to Pediatric Cardiology in Cape Verde via a Collaborative International Telemedicine Service.

    PubMed

    Lapão, Luís Velez; Correia, Artur

    2015-01-01

    This paper addresses the role of international telemedicine services in supporting the evacuation procedures from Cape Verde to Portugal, enabling better quality and cost reductions in the management of the global health system. The Cape Verde, as other African countries, health system lacks many medical specialists, like pediatric cardiologists, neurosurgery, etc. In this study, tele-cardiology shows good results as diagnostic support to the evacuation decision. Telemedicine services show benefits while monitoring patients in post-evacuation, helping to address the lack of responsive care in some specialties whose actual use will help save resources both in provision and in management of the evacuation procedures. Additionally, with tele-cardiology collaborative service many evacuations can be avoided whereas many cases will be treated and followed locally in Cape Verde with remote technical support from Portugal. This international telemedicine service enabled more efficient evacuations, by reducing expenses in travel and housing, and therefore contributed to the health system's improvement. This study provides some evidence of how important telemedicine really is to cope with both the geography and the shortage of physicians. PMID:25980705

  17. Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru

    NASA Astrophysics Data System (ADS)

    Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.

    2013-06-01

    The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The δ34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite

  18. The Development of a Restless Rhyolite Magma Chamber at Laguna del Maule, Chile

    NASA Astrophysics Data System (ADS)

    Andersen, N.; Singer, B. S.; Jicha, B. R.; Fierstein, J.; Vazquez, J. A.

    2013-12-01

    The Laguna del Maule (LdM) volcanic field is a site of rapid crustal deformation at rates in excess of 200 mm/yr since 2007. The uplift is centered in the 16 km diameter LdM lake basin, which is ringed by 21 rhyolite domes and coulees erupted since the last glacial retreat. The lack of previously common andesite and dacite eruptions since 19 ka and coherent major and trace element variation throughout post-glacial time suggests the presence of a large silicic magma body beneath the LdM basin. Assimilation-fractional crystallization modeling predicts the rhyolites evolved at 5 km depth by 73% fractionation of a basaltic parent and modest assimilation of granodiorite accounting for up to 20% of the highest silica rhyolite. AFC processes dominate the evolution from basalt, however the differentiation of the silicic magma is complicated by liquid extraction from crystal mush, remelting of cumulate by intruding basalt, and trace element diffusion. Two-oxide thermometry indicates a relatively hot, oxidized system with eruptive temperatures ranging from 760 - 850° C and fO2 at QFM+2. Pilot ion microprobe 238U-230Th dating of zircon rims suggests the shallow LdM magma system was assembled over a period of 100-200 kyr. 40Ar/39Ar geochronology and field relationships reveal the post-glacial silicic volcanism occurred in two phases. Phase 1 began approximately coincident with deglaciation at 25 ka with the eruption of the rhyolite East of Presa Laguna del Maule. Over the next 6 ky, 6 small rhyodacite domes, a larger rhyodacite flow, and 4 andesite flows erupted in the NW basin and two silicic domes 12 km to the SE. Phase 1 culminates with the eruption of the Espejos rhyolite near the N shore of the lake at 19 ka. The locus of volcanism then migrates SE and phase 2 begins at ~10 ka with the eruption of the Cari Launa rhyolite and the early flows of the Barrancas complex. This period is more voluminous, erupting 4.8 km3 compared to 1.7 km3 during phase 1. Phase 2 produced

  19. Disentangling High Frequency Climate Oscillations In A Volcanic Setting Laguna Lejia, Chile

    NASA Astrophysics Data System (ADS)

    Saltzman, S. H.; Ukstins Peate, I.; Giralt, S.; Peate, D. W.; van Alderwerelt, B. M.

    2015-12-01

    Our understanding of the tropics response to periods of rapid climate change such as CAPE I and the Younger Dryas is limited. Laguna Lejia (23°30'0" S 67°42'0" E ~4,300m asl), Chile is a small alkaline paleolake located in the central Altiplano. The volcanoes Lascar, Chiliques, Aguas Calientes and Acamarachi surround it. 1-3 mm laminations in calcareous clay sediments deposited on the southern terrace of Lejia record high-resolution chemical variability in the lake. Preliminary U-Th ages range from 19,567 +739/- 734 yr to 4208 +431/-429 yr, indicating that the Lejia terrace deposits span both CAPE I and the Younger Dryas, periods of rapid global climate change. Changes in the major and trace element composition, δ18O and δ13 C isotopic ratios, and the amount of Li, Mg, Ca, and Sr that can be readily leached from high magnesium smectite clays provide a direct proxy for hydrologic fluctuations. A climate signal can be detected through reoccurring trends in the chemical variability of these sediments; however, the detection of this signal is complicated by interaction with surrounding volcanic edifices. Statistical methods such as PCA analyses using R have been implemented to separate groupings of volcanic controlled elemental fluctuations (Fe, Zr, Nd, Ti, and Al) from ones under the influence of climate. Spectral analyses have been applied to high-resolution major element data collected on Lejia's paleoshores tufa deposits. Data was collected on Ca, Mg and As at .5 um intervals using a Jeol JXA- 8230 Electron Microprobe at the University of Iowa, Earth and Environmental Sciences. These analyses provided statistical evidence for cyclisity at intervals of 5-15 um and 75-150 um in the banding of the tufas. While previous literature attributes the larger bands to annual chemical cycles the origin of the smaller bands is currently under investigation.

  20. Hydrocarbon concentrations in the American oyster, Crassostrea virginica, in Laguna de Terminos, Campeche, Mexico

    SciTech Connect

    Gold-Bouchot, G.; Norena-Barroso, E.; Zapata-Perez, O.

    1995-02-01

    Laguna de Terminos is a 2,500 km{sup 2} coastal lagoon in the southern Gulf of Mexico, located between 18{degrees} 20` and 19{degrees} 00` N, and 91{degrees} 00` and 92{degrees} 20` W (Figure 1). It is a shallow lagoon, with a mean depth of 3.5 m and connected to the Gulf of Mexico through two permanent inlets, Puerto Real to the east and Carmen to the west. Several rivers, most of them from the Grijalva-Usumacinta basin (the largest in Mexico and second largest in the Gulf of Mexico), drain into the lagoon with a mean annual discharge of 6 X 10{sup 9} m{sup 3}/year. This lagoon has been studied systematically, and is probably one of the best known in Mexico. An excellent overview of this lagoon can be found in Yanez-Arancibia and Day. The continental shelf north of Terminos, the Campeche Bank, is the main oil-producing zone in Mexico with a production of about 2 X 10{sup 6} barrels/day. It is also the main shrimp producer in the southern Gulf, with a mean annual catch of 18,000 tonnes/year, which represents 38 to 50% of the national catch in the Gulf of Mexico. The economic importance of this region, along with its extremely high biodiversity, both in terms of species and habitats, has prompted the Mexican government to study the creation of a wildlife refuge around Terminos. Thus, it is very important to know the current levels of pollutants in this area, as a contribution to the management plan of the proposed protected area. This paper looks at hydrocarbon concentrations in oyster tissue. 14 refs., 3 figs., 21 tabs.

  1. Impact of solar radiation on bacterioplankton in Laguna Vilama, a hypersaline Andean lake (4650 m)

    NASA Astrophysics Data System (ADS)

    FaríAs, MaríA. Eugenia; FernáNdez-Zenoff, Verónica; Flores, Regina; OrdóñEz, Omar; EstéVez, Cristina

    2009-06-01

    Laguna Vilama is a hypersaline Lake located at 4660 m altitude in the northwest of Argentina high up in the Andean Puna. The impact of ultraviolet (UV) radiation on bacterioplankton was studied by collecting samples at different times of the day. Molecular analysis (DGGE) showed that the bacterioplankton community is characterized by Gamma-proteobacteria (Halomonas sp., Marinobacter sp.), Alpha-proteobacteria (Roseobacter sp.), HGC (Agrococcus jenensis and an uncultured bacterium), and CFB (uncultured Bacteroidetes). During the day, minor modifications in bacterial diversity such as intensification of Bacteroidetes' signal and an emergence of Gamma-proteobacteria (Marinobacter flavimaris) were observed after solar exposure. DNA damage, measured as an accumulation of Cyclobutane Pyrimidine Dimers (CPDs), in bacterioplankton and naked DNA increased from 100 CPDs MB-1 at 1200 local time (LT) to 300 CPDs MB-1 at 1600 LT, and from 80 CPDs MB-1 at 1200 LT to 640 CPDs MB-1 at 1600 LT, respectively. In addition, pure cultures of Pseudomonas sp. V1 and Brachybacterium sp. V5, two bacteria previously isolated from this environment, were exposed simultaneously with the community, and viability of both strains diminished after solar exposure. No CPD accumulation was observed in either of the exposed cultures, but an increase in mutagenesis was detected in V5. Of both strains only Brachybacterium sp. V5 showed CPD accumulation in naked DNA. These results suggest that the bacterioplankton community is well adapted to this highly solar irradiated environment showing little accumulation of CPDs and few changes in the community composition. They also demonstrate that these microorganisms contain efficient mechanisms against UV damage.

  2. Maternal and child care among the Tagalogs in Bay, Laguna, Philippines.

    PubMed

    Iocano, F L

    1970-12-01

    An ethnographic picture of certain aspects of maternal and child care among the Tagalogs who inhabit the municipality of Bay, Laguna, Philippines is presented. The objective is to illustrate empirically that traditional practices associated with maternal and child care are not guesswork. Maternal and child care is an important aspect of folk medicine in Bay. Measures to prevent miscarrage, to ease labor, and to insure the safety of the mother have been devised and practiced. The health of both the mother and child receives special attention. The medical concern frequently takes on a religious tone, because most of the practices are interwoven with beliefs in the active participation of supernatural beings in human affairs. Yet, the system of delivery and child care includes steps that are recognized in scientific medicine. There is awareness of what care needs to be taken to insure the safety of mother and child. The inaccessibility of technological resources and of modern knowledge in maternal and child care is what inhibits the peasants from moving away from what has been traditionally proven to be successful. There is sex education in terms of hygiene and care among people in the Bay. Adolescent females receive instructions from their mothers on what to do when they begin to menstruate. The rituals are performed because these are part of the medically approved ways of dealing with menstrual problems. The people in the Bay are familiar with methods of controlling birth. Coitus interruptus is the most widely used folk method of birth control. No other method is readily available within the people's economic means. Soapsuds and vaginal creams are also known to some women. PMID:12278379

  3. Modern sedimentation patterns in Laguna de Medina, Southern Spain, derived from lake surface and soil samples

    NASA Astrophysics Data System (ADS)

    van ´t Hoff, Jasmijn; Schröder, Tabea; Reicherter, Klaus; Held, Peter; Melles, Martin

    2016-04-01

    In September 2014 and March 2015, a 25.66 m long sediment core (Co1313) was retrieved from the centre of Laguna de Medina, a small endorheic salt lake in Cádiz, SW Spain. This record covers the last 9.000 years, thus providing an unique archive for Holocene climatic and environmental changes with extraordinary high temporal resolution. For a better understanding of the palaeoenvironmental proxies to be analysed on the sediment core, the modern processes of sediment formation in the lake and its catchment under known environmental conditions were investigated on a set of 46 lake sediment surface samples and 32 soil surface sediment samples from the lake and the close surroundings, respectively. These samples were analysed for bulk mineralogy (XRD), chemical composition (XRF), grain-size distribution (laser scanner), and carbonate, total organic carbon (TOC), nitrogen (TN) and sulphur (TS) contents (elemental analyser). Based on the mineralogical, geochemical and granulometrical data, the lake can be divided into four zones. The northern shore is characterized by particularly high quartz contents and coarse grain sizes. This reflects input from ancient terraces of the Guadalete River that are exposed in that area. The southern shore is characterised by high calcite contents due to sediment supply from the Cretaceous ´Capas rojaś, a series of Subbetic deep-water marl- and limestones. The southeastern and to a lesser extend the northwestern shores show particularly high dolomite contents, reflecting the Triassic dolomites outcroping in the southeastern catchment. The southeastern shore furthermore is also influenced by strong terrestrial input of the Triassic Keuper facies from the most important inlet, Arroyo Fuente Bermeja, as reflected by high contents of Ti, K, Al, Fe, Rb in the lake sediments. The last zone comprises only a small part of the western shore and is characterized by a relatively high gypsum amount. This does not reflect the geology in the catchment

  4. Focal Mechanisms for Local Earthquakes within a Rapidly Deforming Rhyolitic Magma System, Laguna del Maule, Chile

    NASA Astrophysics Data System (ADS)

    Peterson, D. E.; Keranen, K. M.; Cardona, C.; Thurber, C. H.; Singer, B. S.

    2015-12-01

    Large shallow rhyolitic magma systems like the one underlying the Laguna del Maule Volcanic Field (LdM) atop the Southern Andes, Chile, that comprises the largest concentration of rhyolitic lava and tephra younger than 20 ka at earth's surface, are capable of producing modest to very large explosive eruptions. Moreover, LdM is currently exhibiting magma migration, reservoir growth, and crustal deformation at rates higher than any volcano that is not actively erupting. The long-term build-up of a large silicic magmatic system toward an eruption has yet to be monitored, therefore, precursory phenomena are poorly understood. In January of 2015, 12 broadband, 3-component seismometers were installed at LdM to detect local microearthquakes and tele-seismic events with the goals of determining the migration paths of fluids as well as the boundaries of the magma chamber beneath LdM. These stations complement the 6 permanent stations installed by the Southern Andes Volcano Observatory in 2011. Focal mechanisms were calculated using FOCMEC (Snoke et al., 1984) and P-wave first motions for local events occurring between January and March of 2015 using these 18 broadband stations. Results from six of the largest local events indicate a mixture of normal and reverse faulting at shallow (<10 km) depths surrounding the lake. This may be associated with the opening of fractures to accommodate rising magma in the subsurface and/or stresses induced by the rapid deformation. Two of these events occurred near the center of maximum deformation where seismic swarms have previously been identified. Focal mechanisms from smaller magnitude events will be calculated to better delineate subsurface structure. Source mechanisms will be refined using P-S amplitude ratios and full waveform inversion.

  5. Dynamics of a large, restless, rhyolitic magma system at Laguna del Maule, southern Andes, Chile

    USGS Publications Warehouse

    Singer, Brad S.; Andersen, Nathan L.; Le Mével, Hélène; Feigl, Kurt L.; DeMets, Charles; Tikoff, Basil; Thurber, Clifford H.; Jicha, Brian R.; Cardonna, Carlos; Córdova, Loreto; Gil, Fernando; Unsworth, Martyn J.; Williams-Jones, Glyn; Miller, Craig W.; Fierstein, Judith; Hildreth, Edward; Vazquez, Jorge A.

    2014-01-01

    Explosive eruptions of large-volume rhyolitic magma systems are common in the geologic record and pose a major potential threat to society. Unlike other natural hazards, such as earthquakes and tsunamis, a large rhyolitic volcano may provide warning signs long before a caldera-forming eruption occurs. Yet, these signs—and what they imply about magma-crust dynamics—are not well known. This is because we have learned how these systems form, grow, and erupt mainly from the study of ash flow tuffs deposited tens to hundreds of thousands of years ago or more, or from the geophysical imaging of the unerupted portions of the reservoirs beneath the associated calderas. The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007, the crust there has been inflating at an astonishing rate of at least 25 cm/yr. This unique opportunity to investigate the dynamics of a large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively under way is stimulating a new international collaboration. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ca. 20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. The next phase of this investigation seeks to enlarge the sets of geophysical and geochemical data and to use these observations in numerical models of system dynamics.

  6. Continued Rapid Uplift at Laguna del Maule Volcanic Field (Chile) from 2007 through 2014

    NASA Astrophysics Data System (ADS)

    Le Mével, H.; Feigl, K. L.; Cordova, L.; DeMets, C.; Lundgren, P.

    2014-12-01

    The current rate of uplift at Laguna del Maule (LdM) volcanic field in Chile is among the highest ever observed geodetically for a volcano that is not actively erupting. Using data from interferometric synthetic aperture radar (InSAR) and the Global Positioning System (GPS) recorded at five continuously operating stations, we measure the deformation field with dense sampling in time (1/day) and space (1/hectare). These data track the temporal evolution of the current unrest episode from its inception (sometime between 2004 and 2007) to vertical velocities faster than 200 mm/yr that continue through (at least) July 2014. Building on our previous work, we evaluate the temporal evolution by analyzing data from InSAR (ALOS, TerraSAR-X, TanDEM-X) and GPS [http://dx.doi.org/ 10.1093/gji/ggt438]. In addition, we consider InSAR data from (ERS, ENVISAT, COSMO-Skymed, and UAVSAR), as well as constraints from magneto-telluric (MT), seismic, and gravity surveys. The goal is to test the hypothesis that a recent magma intrusion is feeding a large, existing magma reservoir. What will happen next? To address this question, we analyze the temporal evolution of deformation at other large silicic systems such as Yellowstone, Long Valley, and Three Sisters, during well-studied episodes of unrest. We consider several parameterizations, including piecewise linear, parabolic, and Gaussian functions of time. By choosing the best-fitting model, we expect to constrain the time scales of such episodes and elucidate the processes driving them.

  7. Authigenic, detrital and diagenetic minerals in the Laguna Potrok Aike sediment sequence

    NASA Astrophysics Data System (ADS)

    Nuttin, L.; Francus, P.; Preda, M.; Ghaleb, B.; Hillaire-Marcel, C.

    2013-07-01

    The ˜100 m-long Laguna Potrok Aike sediment sequence yielded a record spanning the Last Glacial period to the Holocene. This paper presents and discusses two aspects of the mineralogy of the lake. The first aspect is based on a semi-quantitative X-ray diffraction analysis of bulk and clay mineralogical assemblages. Minor mineralogical changes are observed throughout the glacial section suggesting relatively uniform sediment sources. The transition into the Holocene is characterized by increasing fluxes of endogenic calcite thought to relate to lower lake levels. The second aspect is based on analysis of uranium-series disequilibria in diagenetic vivianite from the glacial section. U-series ages were expected to yield minimum ages for the host-sediment. Unfortunately, very little authigenic U is present in vivianite grains. The low primary productivity of the lake and thus low organic carbon fluxes might have prevented the development of strong redox gradients at the water-sediment interface and thus reduced diagenetic U-uptake into the sediment. One vivianite sample, at a 56.9 m composite depth, yielded enough authigenic uranium to calculate a 230Th-age of 29.4 ± 5.9 ka (±2σ). This age is younger than the one indicated by the radiocarbon chronology. It is thus concluded that a relatively late diagenetic evolution of the U-Th system characterizes the recovered vivianite minerals. The authigenic U displays a very high excess in 234U (over 238U) with an activity ratio of 4.58 ± 0.58 (±2σ). It suggests that it originates from the transfer of highly fractionated U from surrounding detrital minerals through very low U-content pore waters.

  8. Origin and Population Dynamics of a Novel HIV-1 Subtype G Clade Circulating in Cape Verde and Portugal.

    PubMed

    de Pina-Araujo, Isabel Inês M; Delatorre, Edson; Guimarães, Monick L; Morgado, Mariza G; Bello, Gonzalo

    2015-01-01

    The human immunodeficiency virus type 1 (HIV-1) subtype G is the most prevalent and second most prevalent HIV-1 clade in Cape Verde and Portugal, respectively; but there is no information about the origin and spatiotemporal dispersal pattern of this HIV-1 clade circulating in those countries. To this end, we used Maximum Likelihood and Bayesian coalescent-based methods to analyze a collection of 578 HIV-1 subtype G pol sequences sampled throughout Portugal, Cape Verde and 11 other countries from West and Central Africa over a period of 22 years (1992 to 2013). Our analyses indicate that most subtype G sequences from Cape Verde (80%) and Portugal (95%) branched together in a distinct monophyletic cluster (here called G(CV-PT)). The G(CV-PT) clade probably emerged after a single migration of the virus out of Central Africa into Cape Verde between the late 1970s and the middle 1980s, followed by a rapid dissemination to Portugal a couple of years later. Reconstruction of the demographic history of the G(CV-PT) clade circulating in Cape Verde and Portugal indicates that this viral clade displayed an initial phase of exponential growth during the 1980s and 1990s, followed by a decline in growth rate since the early 2000s. Our data also indicate that during the exponential growth phase the G(CV-PT) clade recombined with a preexisting subtype B viral strain circulating in Portugal, originating the CRF14_BG clade that was later disseminated to Spain and Cape Verde. Historical and recent human population movements between Angola, Cape Verde and Portugal probably played a key role in the origin and dispersal of the G(CV-PT )and CRF14_BG clades. PMID:25993094

  9. Origin and Population Dynamics of a Novel HIV-1 Subtype G Clade Circulating in Cape Verde and Portugal

    PubMed Central

    Guimarães, Monick L.; Morgado, Mariza G.; Bello, Gonzalo

    2015-01-01

    The human immunodeficiency virus type 1 (HIV-1) subtype G is the most prevalent and second most prevalent HIV-1 clade in Cape Verde and Portugal, respectively; but there is no information about the origin and spatiotemporal dispersal pattern of this HIV-1 clade circulating in those countries. To this end, we used Maximum Likelihood and Bayesian coalescent-based methods to analyze a collection of 578 HIV-1 subtype G pol sequences sampled throughout Portugal, Cape Verde and 11 other countries from West and Central Africa over a period of 22 years (1992 to 2013). Our analyses indicate that most subtype G sequences from Cape Verde (80%) and Portugal (95%) branched together in a distinct monophyletic cluster (here called GCV-PT). The GCV-PT clade probably emerged after a single migration of the virus out of Central Africa into Cape Verde between the late 1970s and the middle 1980s, followed by a rapid dissemination to Portugal a couple of years later. Reconstruction of the demographic history of the GCV-PT clade circulating in Cape Verde and Portugal indicates that this viral clade displayed an initial phase of exponential growth during the 1980s and 1990s, followed by a decline in growth rate since the early 2000s. Our data also indicate that during the exponential growth phase the GCV-PT clade recombined with a preexisting subtype B viral strain circulating in Portugal, originating the CRF14_BG clade that was later disseminated to Spain and Cape Verde. Historical and recent human population movements between Angola, Cape Verde and Portugal probably played a key role in the origin and dispersal of the GCV-PT and CRF14_BG clades. PMID:25993094

  10. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the Lower Laguna Madre, Texas

    SciTech Connect

    Mora, M.A.

    1996-06-01

    Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species` diet rather than metabolism. Total PCBs were significantly greater (p < 0.05) in Caspian terns than in the other species. Overall, PCBs in eggs of birds from the Lower Laguna Madre were below concentrations known to affect bird reproduction.

  11. Vegetation history in southern Patagonia: first palynological results of the ICDP lake drilling project at Laguna Potrok Aike, Argentina

    NASA Astrophysics Data System (ADS)

    Schäbitz, Frank; Michael, Wille

    2010-05-01

    Laguna Potrok Aike located in southern Argentina is one of the very few locations that are suited to reconstruct the paleoenvironmental and climatic history of southern Patagonia. In the framework of the multinational ICDP deep drilling project PASADO several long sediment cores to a composite depth of more than 100 m were obtained. Here we present first results of pollen analyses from sediment material of the core catcher. Absolute time control is not yet available. Pollen spectra with a spatial resolution of three meters show that Laguna Potrok Aike was always surrounded by Patagonian Steppe vegetation. However, the species composition underwent some marked proportional changes through time. The uppermost pollen spectra show a high contribution of Andean forest and charcoal particles as it can be expected for Holocene times and the ending last glacial. The middle part shows no forest and relatively high amounts of pollen from steppe plants indicating cold and dry full glacial conditions. The lowermost samples are characterized by a significantly different species composition as steppe plants like Asteraceae, Caryophyllaceae, Ericaceae and Ephedra became more frequent. In combination with higher charcoal amounts and an algal species composition comparable to Holocene times we suggest that conditions during the formation of sediments at the base of the record were more humid and/or warmer causing a higher fuel availability for charcoal production compared to full glacial times.

  12. Estimated natural streamflow in the Rio San Jose upstream from the pueblos of Acoma and Laguna, New Mexico

    USGS Publications Warehouse

    Risser, D.W.

    1982-01-01

    The development of surface and ground water, which began about 1870 in the upper Rio San Jose drainage basin, has decreased the flow of the Rio San Jose on the Pueblo of Acoma and the Pueblo of Laguna. The purpose of this study was to estimate the natural streamflow in the Rio San Jose that would have entered the pueblos if no upstream water development had taken place. Estimates of natural flow were based upon streamflow and precipitation records, historical accounts of streamflow, records of irrigated acreage, and empirically-derived estimates of the effects on streamflow of Bluewater Lake, groundwater withdrawals, and irrigation diversions. Natural streamflow in the Rio San Jose at the western boundary of the Pueblo of Acoma is estimated to be between 13,000 and 15,000 acre-feet per year, based on 55 years of recorded and reconstructed streamflow data from water years 1913 to 1972. Natural streamflow at the western boundary of the Pueblo of Laguna is estimated to be between 17 ,000 and 19,000 acre-feet per year for the same period. The error in these estimates of natural streamflow is difficult to assess accurately, but it probably is less than 25 percent. (USGS)

  13. Distribution and community structure of ichthyoplankton in Laguna Madre seagrass meadows: Potential impact of seagrass species change

    USGS Publications Warehouse

    Tolan, J.M.; Holt, S.A.; Onuf, C.P.

    1997-01-01

    Seasonal ichthyoplankton surveys were made in the lower Laguna Madre, Texas, to compare the relative utilization of various nursery habitats (shoal grass, Halodule wrightii; manatee grass, Syringodium filiforme;, and unvegetated sand bottom) for both estuarine and offshore-spawned larvae. The species composition and abundance of fish larvae were determined for each habitat type at six locations in the bay. Pushnet ichthyoplankton sampling resulted in 296 total collections, yielding 107,463 fishes representing 55 species in 24 families. A broad spectrum of both the biotic and physical habitat parameters were examined to link the dispersion and distribution of both pre-settlement and post-settlement larvae to the utilization of shallow seagrass habitats. Sample sites were grouped by cluster analysis (Ward's minimum variance method) according to the similarity of their fish assemblages and subsequently examined with a multiple discriminant function analysis to identify important environmental variables. Abiotic environmental factors were most influential in defining groups for samples dominated by early larvae, whereas measures of seagrass complexity defined groups dominated by older larvae and juveniles. Juvenile-stage individuals showed clear habitat preference, with the more shallow Halodule wrightii being the habitat of choice, whereas early larvae of most species were widely distributed over all habitats. As a result of the recent shift of dominance from Halodule wrightii to Syringodium filiforme, overall reductions in the quality of nursery habitat for fishes in the lower Laguna Madre are projected.

  14. Selected Hydrologic, Water-Quality, Biological, and Sedimentation Characteristics of Laguna Grande, Fajardo, Puerto Rico, March 2007-February 2009

    USGS Publications Warehouse

    Soler-López, Luis R.; Santos, Carlos R.

    2010-01-01

    Laguna Grande is a 50-hectare lagoon in the municipio of Fajardo, located in the northeasternmost part of Puerto Rico. Hydrologic, water-quality, and biological data were collected in the lagoon between March 2007 and February 2009 to establish baseline conditions and determine the health of Laguna Grande on the basis of preestablished standards. In addition, a core of bottom material was obtained at one site within the lagoon to establish sediment depositional rates. Water-quality properties measured onsite (temperature, pH, dissolved oxygen, specific conductance, and water transparency) varied temporally rather than areally. All physical properties were in compliance with current regulatory standards established for Puerto Rico. Nutrient concentrations were very 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 0.28 milligram per liter, and the average total phosphorus concentration was 0.02 milligram per liter. Chlorophyll a was the predominant form of photosynthetic pigment in the water. The average chlorophyll-a concentration was 6.2 micrograms per liter. Bottom sediment accumulation rates were determined in sediment cores by modeling the downcore activities of lead-210 and cesium-137. Results indicated a sediment depositional rate of about 0.44 centimeter per year. At this rate of sediment accretion, the lagoon may become a marshland in about 700 to 900 years. About 86 percent of the community primary productivity in Laguna Grande was generated by periphyton, primarily algal mats and seagrasses, and the remaining 14 percent was generated by phytoplankton in the water column. Based on the diel studies the total average net community productivity equaled 5.7 grams of oxygen per cubic meter per day (2.1 grams of carbon per cubic meter per day). Most of this productivity was ascribed to periphyton and macrophytes

  15. Evaluation Report of the Native American Consortium for Educational and Assistive Technologies for Indian Children Living on the Acoma and Laguna Pueblos.

    ERIC Educational Resources Information Center

    Zastrow, Leona M.

    The New Mexico State Department of Education received a federal grant to provide educational and assistive technology for American Indian children living in the Pueblos of Laguna and Acoma, New Mexico. During the 2-year project, more than 229 assistive technology items were purchased, and some form of assistive technology was provided to 121…

  16. Modelling Temporal and Spatial Variations in Gravimetric Data at Laguna del Maule, Chile

    NASA Astrophysics Data System (ADS)

    Miller, C. A.; Williams-Jones, G.; Currenti, G. M.; Le Mével, H.; Tikoff, B.

    2015-12-01

    Since 2013 we have undertaken annual microgravity and deformation surveys at Laguna del Maule, Chile, to characterise the causes of rapid inflation observed since 2007. The maximum increase in residual gravity is 125 ± 12 microgal between 2013 and 2014, but only 60 ± 15 microgal between 2014 and 2015. The spatial pattern of the gravity anomaly also appears to vary with time. During the 2013-2014 interval, the location of the maximum increase in gravity is near the maximum of the deformation pattern observed by Interferometric Synthetic Aperture Radar (InSAR) between 2007 and 2015 (Le Mével et al. 2015, Geophys. Res. Lett.). During the 2014-2015 interval, the maximum increase in gravity occurs approximately 4 kilometers south west of the center of inflation. Here we present initial source models to explain the observed increases in microgravity. The models are decribed in a framework derived from new spatial Bouguer gravity data, which allows for a better interpretation of time-lapse models. We use a Monte Carlo-type Genetic Algorithm to solve for the optimum source parameters of a range of finite geometry models including spherical, ellipsoidal and sill-like bodies. Finally we compare the finite geometry models to free geometry 3D gravity inversion models. Sources for the 2013-2014 interval locate close to the center of deformation at a depth of approximately 2 to 4 km. Sources for the 2014-2015 interval locate approximately 3 km southwest of the 2013-2014 source, at a similar depth. Positive density contrasts of several hundred kg/m3 are recovered from the source models. The 2013-2014 source locates close to the center of an approximately 15 milliGal Bouguer gravity low while the 2014-2015 source locates close to the edge of the gravity low. Our initial interpretation is that the Bouguer gravity low represents a low density magma body and the 2013-2015 residual microgravity increases represent spatially varying injections of fresh dense magma into that body.

  17. Widespread Gravity Changes and CO2 Degassing at Laguna Del Maule, Chile, Accompanying Rapid Uplift

    NASA Astrophysics Data System (ADS)

    Miller, C. A.; Williams-Jones, G.; Le Mevel, H.; Tikoff, B.

    2014-12-01

    Laguna Del Maule (LdM), located on the Andes range crest in central Chile, is one of the most active rhyolite volcanic fields on Earth with 36 post glacial rhyolitic eruptions. Since 2007, LdM has accumulated over 1.8 m of uplift at rates of up to 300 mm per year. We hypothesize that this rapid uplift results from the injection of basaltic magma into the base of a rhyolite chamber. To test this hypothesis we undertook a dynamic gravity study, complimented with CO2 soil gas measurements. We established a 35 station dynamic gravity and differential GPS network around the lake in April 2013 and undertook initial CO2 measurements. We resurveyed the network in January 2014 and expanded the soil gas coverage. From these surveys we calculated 0.134 ± 0.030 mGal residual gravity change (Δg) accompanied by 281 ± 13 mm of uplift over the 10 month period. Statistical tests show that the results of the 2013 and 2014 surveys are different at p < 0.01. The Δg anomaly occupies an area of 5 km x 10 km, oriented E/W, and centred in the south eastern part of the lake, and is coincident with the area of maximum uplift. Gaussian integration of Δg yields an excess mass of ~1.2 x 1011 kg. Assuming a density of 2700 kg/m3 this results in a volume of around 0.044 km3. In the 10 month time interval between surveys the calculated volume change rate was 41 ± 1 m3/s. We examine gravity / height change (Δg/Δh) relationships to determine if changes observed relate soley to increased mass or if density changes are involved. In addition to the Δg and Δh measurements, CO2 soil concentrations of up to 7 % are recorded around the entire lake basin. We will discuss modelling of the Δh and Δg data to explore the geometry and physical parameters of the mass and pressure source and discuss the relationship of CO2 anomalies to these models.

  18. Magnetotelluric Studies of the Laguna del Maule Volcanic Field, Central Chile

    NASA Astrophysics Data System (ADS)

    Cordell, D. R.; Unsworth, M. J.; Diaz, D.; Pavez, M.; Blanco, B.

    2015-12-01

    Geodetic data has shown that the surface of the Laguna del Maule (LdM) volcanic field in central Chile has been moving upwards at rates >20 cm/yr since 2007 over a 200 km2 area. It has been hypothesized that this ground deformation is due to the inflation of a magma body at ~5 km depth beneath the lake (2.8 km b.s.l.). This magma body is a likely source for the large number of rhyolitic eruptions at this location over the last 25 ka. A dense broadband magnetotelluric (MT) array was collected from 2009 to 2015 and included data from a geothermal exploration project. MT phase tensor analysis indicates that the resistivity structure of the region is largely three-dimensional for signals with periods longer than 1 s, which corresponds to depths >5 km. The MT data were inverted using the ModEM inversion algorithm to produce a three-dimensional electrical resistivity model which included topography. Four primary features were identified in the model: 1) A north-south striking, 10 km by 5 km, low-resistivity zone (<5 Ωm) northwest of the inflation centre at a depth of ~5 km (2.8 km b.s.l.) is interpreted as a zone of partial melt which may be supplying material via conduits to account for the observed ground deformation; 2) A shallow low-resistivity feature ~400 m beneath the lake surface (1.8 km a.s.l.) and spatially coincident with the inflation centre is interpreted to be a zone of hydrothermal alteration; 3) A thin, low-resistivity feature to the west of LdM at a depth of ~250 m (2.2 km a.s.l.) is interpreted to be the clay cap of a potential geothermal prospect; 4) A large, low-resistivity zone beneath the San Pedro-Tatara Volcanic Complex to the west of LdM at a depth of ~10 km (8 km b.s.l.) is interpreted to be a zone of partial melt. Further MT data collection is planned for 2016 which will expand the current grid of MT stations to better constrain the lateral extent of the observed features and give greater insight into the dynamics of this restless magma system.

  19. Cooling History for the Sierra Laguna Blanca (NW Argentina) on the Southern Puna Plateau, Central Andes

    NASA Astrophysics Data System (ADS)

    Zhou, R.; Schoenbohm, L. M.; Sobel, E. R.; Stockli, D. F.; Glodny, J.

    2014-12-01

    Various dynamic models have been proposed to explain deformation history and topographic evolution for the southern Altiplano-Puna Plateau, including inversion of the Cretaceous Salta rift structures, formation of an orogenic wedge, flat subduction, climate-tectonic coupling, and lithospheric foundering. Controversies persist in the southern Puna Plateau, where preexisting rift structures are unknown and Cenozoic shortening events are sparsely documented. The 6-km high Sierra Laguna Blanca (LB) (NW Argentina) is among the most outstanding topographic features in the interior of the southern Puna Plateau. We document cooling history for LB with apatite (U-Th)/He, apatite fission-track and zircon (U-Th)/He thermochronometers for a vertical profile from 3.6-5.6 km on its eastern flank. Preliminary results from apatite fission-track (AFT) analysis yield ages ranging from 45-65 Ma, with top samples being the oldest. Dpar values for all samples are low (1.54 to 1.74), suggesting a relatively low-temperature partial annealing zone. All samples have shortened mean track lengths ranging from 10.9 to 12.3 micrometers, suggesting partial resetting. Preliminary apatite U-Th/He (AHe) ages are compatible with AFT ages but are widely dispersed, perhaps due to U zoning and small U-rich inclusions which have been observed on AFT external detectors. Inverse modeling of AFT data and selected AHe data using the HeFTy program reveal two major cooling events for LB. All models start ~90-70 Ma and immediately decrease their temperatures to ~60°C before ~50 Ma. Samples may have stayed ~60°C without additional thermal events until ~15-10 Ma, when the most recent cooling event took place, bringing all samples to surface temperature. Our first finding is that the interior of the southern Puna Plateau may have been influenced by the Salta Rift during the Cretaceous, extending the known zone of influence further west. Second, the most recent cooling phase (mid-late Miocene) is consistent

  20. Plant growth stage-specific injury and economic injury level for verde plant bug, Creontiades signatus (Hemiptera: Miridae), on cotton: Effect of bloom period of infestation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The verde plant bug, Creontiades signatus Distant (Hemiptera: Miridae), has emerged as a threat to cotton in South Texas, causing boll damage similar to boll-feeding stink bugs (Hemiptera: Pentatomidae). Verde plant bugs were released into caged cotton for a one-week period to characterize the effec...

  1. Availability of ground water in parts of the Acoma and Laguna Indian Reservations, New Mexico

    USGS Publications Warehouse

    Dinwiddie, George A.; Motts, Ward Sundt

    1964-01-01

    The need for additional water has increased in recent years on the Acoma and Laguna Indian Reservations in west-central New Mexico because the population and per capita use of water have increased; the tribes also desire water for light industry, for more modern schools, and to increase their irrigation program. Many wells have been drilled in the area, but most have been disappointing because of small yields and poor chemical quality of the water. The topography in the Acoma and Laguna Indian Reservations is controlled primarily by the regional and local dip of alternating beds of sandstone and shale and by the igneous complex of Mount Taylor. The entrenched alluvial valley along the Rio San Jose, which traverses the area, ranges in width from about 0.4 mile to about 2 miles. The climate is characterized by scant rainfall, which occurs mainly in summer, low relative humidity, and large daily fluctuations of temperature. Most of the surface water enters the area through the Rio San Jose. The average annual streamflow past the gaging station Rio San Jose near Grants, N. Mex. is about 4,000 acre-feet. Tributaries to the Rio San Jose within the area probably contribute about 1,000 acre-feet per year. At the present time, most of the surface water is used for irrigation. Ground water is obtained from consolidated sedimentary rocks that range in age from Triassic to Cretaceous, and from unconsolidated alluvium of Quaternary age. The principal aquifers are the Dakota Sandstone, the Tres Hermanos Sandstone Member of the Mancos Shale, and the alluvium. The Dakota Sandstone yields 5 to 50 gpm (gallons per minute) of water to domestic and stock wells. The Tres Hermanos sandstone Member generally yields 5 to 20 gpm of water to domestic and stock wells. Locally, beds of sandstone in the Chinle and Morrison Formations, the Entrada Sandstone, and the Bluff Sandstone also yield small supplies of water to domestic and stock wells. The alluvium yields from 2 gpm to as much as 150

  2. Palos Verdes Shelf oceanographic study; data report for observations December 2007–April 2008

    USGS Publications Warehouse

    Rosenberger, Kurt J.; Noble, Marlene A.; Sherwood, Christopher R.; Martini, Marinna M.; Ferreira, Joanne T.; Montgomery, Ellyn T.

    2011-01-01

    Beginning in 1997, the Environmental Protection Agency (EPA) defined a contaminated section of the Palos Verdes Shelf region in southern California as a Superfund Site, initiating a continuing investigation of this area. The investigation involved the EPA, the U.S. Geological Survey (USGS), Science Applications International Corporation (SAIC), Los Angeles County Sanitation Districts (LACSD) data, and other allied agencies. In mid-2007, the Palos Verdes Shelf project team identified the need for additional data on the sediment properties and oceanographic conditions at the Palos Verdes Superfund Site and deployed seven bottom platforms, three subsurface moorings, and three surface moorings on the shelf. This additional data was needed to support ongoing modeling and feasibility studies and to improve our ability to model the fate of the effluent-affected deposit over time. It provided more detail on the spatial variability and magnitude of resuspension of the deposit during multiple storms that are expected to transit the region during a winter season. The operation began in early December 2007 and ended in early April 2008. The goal was to measure the sediment response (threshold of resuspension, suspended-sediment concentrations, and suspended-sediment transport rates) to bed stresses associated with waves and currents. Other objectives included determining the structure of the bottom boundary layer (BBL) relating nearbed currents with those measured at 10 m above bottom (mab) and comparing those with the long-term data from the LACSD Acoustic Doppler Current Profiler (ADCP) deployments for nearbed current speed and direction. Low-profile tripods with high-frequency ADCPs co-located with two of the large tripods were selected for this goal. This report describes the data obtained during the field program, the instruments and data-processing procedures used, and the archive that contains the data sets that have passed our quality-assurance procedures.

  3. Quaternary Deformation History of the Palos Verdes Fault in San Pedro Bay using 3D and 2D Seismic data

    NASA Astrophysics Data System (ADS)

    Rigor, A.; Mellors, R. J.; Legg, M.; Francis, D.

    2002-12-01

    The Palos Verdes fault has one of the highest slip rates of the Los Angeles basin structures. Using a combination of exploration industry 3-D seismic data and 2-D high-resolution profiles through San Pedro Bay, we are preparing detailed maps of the shallow geometry and deformation history of the Palos Verdes fault. By mapping prominent shallow reflection horizons, that represent important late Pliocene and Quaternary sedimentary sequences, we can estimate the Quaternary deformation history of this important fault zone and identify whether significant changes in tectonic style or rates of deformation have occurred that may affect estimates of earthquake potential in the southern California region. We have identified about six major seismic stratigraphic sequences in the Wilmington Graben east of the Palos Verdes fault zone representing the time period from Repettian (Pliocene) to late Quaternary. Three of these are in the shallow section and clearly imaged by the high-resolution profiles. One of the more significant features we observe regarding these sequences is that the uplift of the Palos Verdes anticlinorium, represented by sedimentary growth wedges adjacent to the fault zone, appears to stop and start. These changes in vertical deformation character may represent important local changes in the tectonic style along the fault zone. For constraints on lateral deformation history, we are attempting to identify possible meanders or other irregularities in the Los Angeles - San Gabriel river system that generally flows straight along the northeast flank of the Palos Verdes anticlinorium before plunging down the slope in the San Gabriel submarine canyon. Channel thalwegs and margins offset by the Palos Verdes fault zone would provide requisite piercing points for measuring right-slip since channels filled. Major segment boundaries, such as the 3-km long north-trending releasing bend and Beta oil field complex restraining bend structure may provide other important

  4. Satellite snowcover and runoff monitoring in central Arizona. [Salt River Project: Salt-Verde Watershed

    NASA Technical Reports Server (NTRS)

    Schumann, H. H.; Kirdar, E.; Warskow, W. L. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. Although the very high resolution experimental LANDSAT imagery permits rapid snow cover mapping at low cost, only one observation is available very 9 days. In contrast, low resolution operational imagery acquired by the ITOS and SMS/GOES satellites provide the daily synoptic observations necessary to monitor the rapid changes in snow covered areas in the entire Salt-Verde watershed. Geometric distortions in meteorological satellite imagery require specialized optical equipment or digital image processing for snow cover mapping.

  5. Aula Verde: art as experience in community-based environmental education.

    PubMed

    Abarca, Marco A

    2010-01-01

    After winning a class-action lawsuit against unconstitutional prison conditions in Puerto Rico, Marco Abarca managed to direct part of the fine monies accumulated throughout years of litigation toward an investment that would improve the living conditions in one of the largest and poorest housing projects in Puerto Rico. With the participation of parolees and probationers, he began to transform a mosquito-infested badland into a natural haven. Then, with the help of science educators, the group designed a workshop for elementary school children on urban ecology. As the participants organized, what developed was a community-based, self-employed enterprise known as Aula Verde. PMID:20391620

  6. Composition and origin of PM10 in Cape Verde: Characterization of long-range transport episodes

    NASA Astrophysics Data System (ADS)

    Salvador, P.; Almeida, S. M.; Cardoso, J.; Almeida-Silva, M.; Nunes, T.; Cerqueira, M.; Alves, C.; Reis, M. A.; Chaves, P. C.; Artíñano, B.; Pio, C.

    2016-02-01

    A receptor modelling study was performed to identify source categories and their contributions to the PM10 total mass at the Cape Verde archipelago. Trajectory statistical methods were also used to characterize the main atmospheric circulation patterns causing the transport of air masses and to geographically identify the main potential source areas of each PM10 source category. Our findings point out that the variability of the PM10 levels at Cape Verde was prompted by the advections of African mineral dust. The mineral dust load was mainly composed by clay-silicates mineral derived elements (22% of the PM10 total mass on average) with lower amounts of carbonates (9%). A clear northward gradient was observed in carbonates concentration that illustrates the differences in the composition according to the source regions of mineral dust. Mineral dust was frequently linked to industrial emissions from crude oil refineries, fertilizer industries as well as oil and coal power plants, located in the northern and north-western coast of the African continent (29%). Sea salt was also registered in the PM10 mass during most part of the sampling period, with a lower impact in the PM10 levels than the mineral dust one (26%). Combustion aerosols (6%) reached the highest mean values in summer as a consequence of the emissions from local-regional sources. Biomass burning aerosols produced from October to November in sub-sahelian latitudes, had a clear influence in the content of elemental carbon (EC) recorded at Cape Verde but a small impact in the PM10 total mass levels. A minor contribution to the PM10 mass has been associated to secondary inorganic compounds-SIC. Namely, ammonium sulfate and nitrate (SIC 1-5%) and calcium sulfate and nitrate (SIC 2-3%). The main origin of SIC 1 was attributed to emissions of SO2 and NOx from industrial sources located in the northern and north-western African coast and from wildfires produced in the continent. SIC 2 had a clear regional origin

  7. A High-Resolution Reconstruction of Late Holocene Environmental Change from Laguna Ek'Naab, Northern Holmul Region, Peten, Guatemala

    NASA Astrophysics Data System (ADS)

    Anderson, L.; Wahl, D.; Estrada-Belli, F.

    2015-12-01

    Widespread demographic shifts in the southern Maya lowlands at the end of the Classic period have been attributed to environmental change caused by human activity and/or climate variability. Fire was essential to landscape modification and was a primary agent of environmental change associated with prehispanic land use. While several studies have provided insight into the dynamic relationship between natural and anthropogenic drivers of change, defining the specific interplay between natural environmental change, human modification of the environment, and cultural response to changes remains a persistent challenge. Here we present the results of a multi-proxy study that reconstructs fire history, agricultural land use, and environmental change during and after Pre-Columbian Maya settlement. Results are interpreted in the context of settlement history as inferred from archaeological mapping around the study site. Our findings suggest landscape disturbance, as indicated by erosion, local burning, and nearby maize agriculture, was at its peak during the Early Classic period. This disturbance was likely due to large-scale settlement at the nearby site of Witzna'. All proxies indicate a slow decline in disturbance into the Late Classic period, beginning around 1300 cal yr BP. Cival and Chanchich, two proximal site centers to the south of Laguna Ek'Naab, supported their largest populations during the Late Preclassic and Late Classic, with little or no settlement during the Early Classic. The data from Laguna Ek'Naab suggests that Witzna' may have been an important center during the Early Classic. Whether the decreasing environmental degradation after 1240 cal yr BP is do to a decline in local population or changing land use strategies is not discernable based on the data thus far. However, the near complete absence of burning and continued decrease in erosion from 1240-1090 cal yr BP suggests little anthropogenic activity in the area. Burning resumes in the watershed

  8. Evolution of Rhyolite at Laguna del Maule, a Rapidly Inflating Volcanic Field in the Southern Andes

    NASA Astrophysics Data System (ADS)

    Andersen, N. L.; Singer, B. S.; Jicha, B. R.; Hildreth, E. W.; Fierstein, J.; Rogers, N. W.

    2012-12-01

    The Laguna del Maule Volcanic Field (LdM) is host to both the foremost example of post-glacial rhyolitic volcanism in the southern Andes and rapid, ongoing crustal deformation. The flare-up of high-silica eruptions was coeval with deglaciation at 24 ka. Rhyolite and rhyodacite domes and coulees totaling 6.5 km3 form a 20 km ring around the central lake basin. This spatial and temporal concentration of rhyolite is unprecedented in the history of the volcanic field. Colinear major and trace element variation suggests these lavas share a common evolutionary history (Hildreth et al., 2010). Moreover, geodetic observations (InSAR & GPS) have identified rapid inflation centered in the western side of the rhyolite dome ring at a rate of 17 cm/year for five years, which has accelerated to 30 cm/yr since April 2012. The best fit to the geodetic data is an expanding magma body located at 5 km depth (Fournier et al., 2010; Le Mevel, 2012). The distribution of high-silica volcanism, most notably geochemically similar high-silica rhyolite lavas erupted 12 km apart of opposite sides of the lake within a few kyr of each other, raises the possibility that the shallow magma intrusion represents only a portion of a larger rhyolitic body, potentially of caldera forming dimensions. We aim to combine petrologic models with a precise geochronology to formulate a model of the evolution of the LdM magma system to its current state. New 40Ar/39Ar age determinations show rhyolitic volcanism beginning at 23 ka with the eruption of the Espejos rhyolite, followed by the Cari Launa Rhyolite at 14.5 ka, two flows of the Barrancas complex at 6.4 and 3.9 ka, and the Divisoria rhyolite at 2.2 ka. In contrast, significant andesitic and dacitic volcanism is largely absent from the central basin of LdM since the early post-glacial period suggesting a coincident basin-wide evolution from andesite to dacite to rhyolite and is consistent with a shallow body of low-density rhyolite blocking the eruption

  9. Recovery of floral and faunal communities after placement of dredged material on seagrasses in Laguna Madre, Texas

    NASA Astrophysics Data System (ADS)

    Sheridan, P.

    2004-03-01

    The objectives of this project were to determine how long alterations in habitat characteristics and use by fishery and forage organisms were detectable at dredged material placement sites in Laguna Madre, Texas. Water, sediment, seagrass, benthos, and nekton characteristics were measured and compared among newly deposited sediments and nearby and distant seagrasses each fall and spring over three years. Over this period, 75% of the estimated total surface area of the original deposits was either re-vegetated by seagrass or dispersed by winds and currents. Differences in water and sediment characteristics among habitat types were mostly detected early in the study. There were signs of steady seagrass re-colonization in the latter half of the study period, and mean seagrass coverage of deposits had reached 48% approximately three years after dredging. Clovergrass Halophila engelmannii was the initial colonist, but shoalgrass Halodule wrightii predominated after about one year. Densities of annelids and non-decapod crustaceans were generally significantly greater in close and distant seagrass habitats than in dredged material habitat, whereas densities of molluscs were not significantly related to habitat type. Nekton (fish and decapod) densities were almost always significantly greater in the two seagrass habitats than in dredged material deposits. Benthos and nekton communities in dredged material deposits were distinct from those in seagrass habitats. Recovery from dredged material placement was nearly complete for water column and sediment components after 1.5 to 3 years, but recovery of seagrasses, benthos, and nekton was predicted to take 4 to 8 years. The current 2 to 5 years dredging cycle virtually insures no time for ecosystem recovery before being disturbed again. The only way to ensure permanent protection of the high primary and secondary productivity of seagrass beds in Laguna Madre from acute and chronic effects of maintenance dredging, while ensuring

  10. Magma Injection Models to Quantify Reservoir Dynamics at Laguna del Maule Volcanic Field, Chile, between 2007 and 2015.

    NASA Astrophysics Data System (ADS)

    Le Mével, H.; Gregg, P. M.; Feigl, K. L.

    2015-12-01

    Moving beyond the widely used kinematic models for the deformation sources, we present new dynamic models to describe the process of injecting magma into an existing magma reservoir. The 3-dimensional numerical models account for a viscoelastic, gravitationally loaded domain with spatially variable rheological properties. A Newtonian fluid characterized by its viscosity, density, and overpressure (relative to the lithostatic value) intrudes into a viscoelastic solid via a conduit leading to the reservoir. Using the Finite Element Method (FEM), we simultaneously solve the coupled quasi-static elastic and Navier-Stokes governing equations for the solid and the fluid, respectively, using the COMSOL Multiphysics software. The fluid and the solid interact through buoyancy and viscoelastic relaxation, leading to time-dependent deformation. To quantify the "strength" of the source, we define the product of the volume change (in cubic meters) and pressure change (in Pascals) as the "volcanic moment" (in Newton-meters or Joules). This quantity serves as a basis for comparing the calculated displacement fields to analytical solutions. After validating our injection model, we apply it to the ongoing episode of unrest at Laguna del Maule (Chile). Since 2007, the volcanic field there has been deforming at an exceptionally high rate, with vertical velocities up to 200 mm/yr, as measured by GPS and Interferometric Synthetic Aperture Radar (InSAR) between 2013 and 2014, as described recently by Le Mével et al. (2015, Geophys. Res. Lett. http://dx.doi.org/10.1002/2015GL064665). We are modeling the geodetic data to analyze the temporal and spatial evolution of the displacement. These models constrain the mass flux of material into the reservoir and thus its impact on the stress in the crust. Our results contribute to understanding the current unrest episode at Laguna del Maule and to assessing geodetic signals at other active volcanoes.

  11. 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.

  12. DDE in sediments of the Palos Verdes shelf, California: In situ transformation rates and geochemical fate

    USGS Publications Warehouse

    Eganhouse, R.P.; Pontolillo, J.

    2008-01-01

    From 1947 to 1971 the world's largest manufacturer of DDT discharged process wastes into the sewers of Los Angeles County. Roughly 870-1450 t of DDT were released to the ocean off Palos Verdes, CA, a portion of which (???100 t) resides in sediments on the continental shelf and slope. The most abundant DDT compound in the sediments, p,p???-DDE, is degrading by reductive dechlorination, butthe rate of transformation and factors controlling it are not well understood. In order to estimate in situ transformation rates and predict the long-term fate of p,p???-DDE, box cores were collected in 1992 and 2003 from a single location on the Palos Verdes Shelf and analyzed for 8 DDT compounds and 84 polychlorinated biphenyl (PCB) congeners. The PCBs show no evidence of dechlorination, and inventories did not change between 1992 and 2003. By contrast, the inventory of p,p???-DDE decreased by 43%, whereas that of p,p???-DDMU, the putative reductive dechlorination product increased by 34%. The first-order transformation rate for p,p???-DDE at the study site is 0.051 ?? 0.006 yr-1. A multistep reaction model suggests that inventories of p,p???-DDE and p,p???-DDMU will continue to decline, whereas that of p,p???-DDNU will reach a maximum around 2014.

  13. [Vector-borne parasites of dogs on the Islands of Cabo Verde].

    PubMed

    Kirchner, Marlene; Brunner, Adrian; Edelhofer, Renate; Joachim, Anja

    2008-01-01

    During an animal welfare campaign on the Islands of Cape Verde (in the capital Praia on the island of Santiago) a total of 57 dogs were examined for ectoparasites and blood parasites. 84% of the animals were infested with arthropods, mostly ticks. Haemotropic parasites were examined via blood smear, polymerase chain reaction (PCR) and/or serology. 23 dogs had single infections, five multiple infections with haemoparasites. In eight dogs Ehrlichia canis and in one Amaplasma phagocytophilum were detected by PCR, while 43.1% and 36.2% respectively were serologically positive. In 23 blood smears Babesia gibsoni, but no Babesia canis could be detected. In four cases Hepatozoon canis was found in the smears. All animals were negative for Dirofilaria larvae or antibodies against Leishmania. Arthropod-infested animals more frequently harboured babesiae (44%), ehrlichiae (19%) or H. canis (8%) compared to non-infested animals (20%, 0%, 0%). In bitches and dogs aged one year or less babesiae were more frequently detected (48% of the bitches and 13% of the male dogs; 45% of animals less than one year and 26% of the older ones). Due to the high infection rates the import of animals from Cabo Verde to Central Europe must be seen as critical, since an endemisation of (sub-)tropical infectious agents cannot be excluded. PMID:19066773

  14. Sources of springs supplying base flow to the Verde River headwaters, Yavapai County, Arizona

    USGS Publications Warehouse

    Wirt, Laurie; Hjalmarson, H.W.

    1999-01-01

    Multiple lines of evidence were used to identify source aquifers, quantify their respective contributions, and trace the ground-water flow paths that supply base flow to the uppermost reach of the Verde River in Yavapai County, Arizona. Ground-water discharge via springs provides base flow for a 24-mile long reach from the mouth of Granite Creek (river mile 2.0) to Perkinsville (river mile 26). The flowing reach is important to downstream water users, maintains critical habitat for the recovery of native fish species, and has been designated a Wild and Scenic River. Sources of base flow are deduced from (a) geologic information, (b) ground-water levels, (c) precipitation and streamflow records, (d) downstream changes in base-flow measurements, (e) hydrologic analysis of water-budget components, and (f) stableisotope geochemistry of ground water, surface water, and springs. Combined, this information clearly indicates that interconnected aquifers in Big Chino Valley are the primary source of Big Chino Springs, presently supplying at least 80 percent of the upper Verde River?s base flow.

  15. Rainfall kinetic energy-intensity and rainfall momentum-intensity relationships for Cape Verde

    NASA Astrophysics Data System (ADS)

    Sanchez-Moreno, Juan Francisco; Mannaerts, Chris M.; Jetten, Victor; Löffler-Mang, Martin

    2012-08-01

    Momentum and kinetic energy of rainfall are widely used indices to describe erosivity, the ability of rainfall to detach soil particles and erode the landscape. An optical laser disdrometer was installed in Santiago Island, Cape Verde, between September 2008 and September 2010 to measure rainfall intensity and size distribution of raindrops. A total time series of 5129 observations of radar reflectivity, visibility, rainfall intensity and number of particles were gathered. Rainfall kinetic energy expenditure KEtime (J m-2 h-1), kinetic energy content KEmm (J m-2 mm-1) and momentum flux MtA (kg m s-1 m-2 s-1) were calculated and fitted to different known experimental equations. The best fit between rainfall intensity and kinetic energy expenditure, kinetic energy content and momentum were obtained with power-law equations. These equations were validated in two independent events corresponding to 2008 and 2009, producing high correlation coefficients. The results show that for Cape Verde, KEtime is a more appropriate index to relate with rainfall intensity, and that kinetic energy expenditure and momentum flux are interchangeable parameters for erosivity estimation. New relationships relating kinetic energy and rainfall intensity, and momentum and rainfall intensity were derived, which contribute to the characterization of rainfall originating from tropical depressions at lower latitudes.

  16. Palo verde story: a foundation for future multi-station nuclear power plants

    SciTech Connect

    Van Brunt, E.E. Jr.; Ferguson, C.

    1988-01-01

    In 1973, the design and planning for the Palo Verde Nuclear Generating Station was started featuring three 3800 MWt Combustion Engineering Standard System 80 Nuclear Steam Supply Systems. Arizona Public Service Company (APS) was the Project Manager and Operating Agent and Bechtel Power Corporation the architect/engineer and constructor. The Palo Verde units are located in a desert environment some 50 miles west of Phoenix, Arizona. It is a dry site in that there are no liquid discharges from the site. The cooling tower makeup water sewage is waste effluent from the City of Phoenix treated at an on site reclamation facility. The effluent has had primary and secondary treatment at the Phoenix plant prior to delivery to PVNGS. The units are physically separate from each other but are of identical design. There are no shared safety systems between the units. This paper presents some of the engineering and management practices used during design, construction, and startup and operational experiences and other unique features of this multi-unit nuclear station.

  17. Observations of high-frequency harmonic tremor in Fogo, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Heleno, Sandra I. N.; Faria, Bruno V. E.; Bandomo, Zuleyka; Fonseca, João F. B. D.

    2006-11-01

    We report observations of high-frequency (HF) volcanic tremor, with spectral peaks in the band 5-20 Hz, recorded in Fogo Island, Cape Verde archipelago. Several occurrences are characterized by regularly spaced spectral peaks, but the fundamental frequency is missing. The signal is strong enough to be weakly detected on the southern islands of the archipelago, at distances of 20, 80 and 120 km from Fogo. This widespread detection of the HF tremor suggests that the propagation of the energy is made as T-waves propagating in the ocean sound channel. After correcting for site effects, the spatial pattern of amplitudes in Fogo and Brava Islands clearly indicates an offshore source. Active seamounts recently discovered in the vicinity of Fogo and Brava Islands [Hansteen, T.H., Grevemeyer, I., Hanel, K., Kraus, G., Schneider, J., Masson, D.G., Le Bas, T., Faria, B., 2006. Seamounts at the Cape Verde Islands: the geosphere-hydrosphere-biosphere connection, Seamount Biogeosciences Network, Workshop volume, La Jolla, March 24-25, 2006, 27-29.] are proposed to be the source of the HF tremor.

  18. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    USGS Publications Warehouse

    Heilweil, V.M.; Solomon, K.D.; Gingerich, S.B.; Verstraeten, Ingrid M.

    2009-01-01

    Stable isotopes (??18O, ??2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that S??o Nicolau Island's Ribeira Faj?? Basin has groundwater residence times of more than 50 years, whereas Fogo Island's Mosteiros Basin and Santo Ant??o Island's Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion. ?? Springer-Verlag 2009.

  19. The Canary and Cape Verde hot spots: morphological and geological links

    NASA Astrophysics Data System (ADS)

    Patriat, M.; Olivet, J. L.; Sahabi, M.; Aslanian, D.; Géli, L.

    2003-04-01

    The Canary and Cape-Verde achipelagoes are two groups of volcanic islands, 1400 km apart, located along the African margin of the Central Atlantic Ocean. They are often cited as case examples of the surface expression of two distinct hot-spot plumes. Their distribution, which does not define a line as much oceanic islands of the Pacific Ocean do, but a cluster, is considered as an indication of the steadiness of the African plate in the hot spots reference frame. From a bibliographic review and an examination of existing seismic profiles we emphasize the similarities existing between these two archipelagoes. - A continuous morphological basement ridge does exist along the margin that links the two archipelagoes. - An almost synchronous geological evolution is deduced from the stratigraphy of Fuerteventura island (Canary), Maio island (Cape-Verde), and the few DSDP holes in the area. The stratigraphic record evidences a Late Cretaceous/early Tertiary uplift following the classical oceanic subsidence but pre-dating the Tertiary volcanism that made the islands, or at least their aerial part. These geological arguments induces us to contest the relevance to put two distinct hot spot plumes forward to explain the evolution of such closely related geological structures.

  20. U-Pb zircon constraints on the age and provenance of the Rocas Verdes basin fill, Tierra del Fuego, Argentina

    NASA Astrophysics Data System (ADS)

    Barbeau, David L.; Gombosi, David J.; Zahid, Khandaker M.; Bizimis, Michael; Swanson-Hysell, Nicholas; Valencia, Victor; Gehrels, George E.

    2009-12-01

    The Late Jurassic to Early Cretaceous Rocas Verdes basin constitutes one of the most poorly understood components of the southernmost Andes. As a result, accurate reconstructions and interpretations of deformation associated with the Andean orogeny and the kinematics of Scotia arc development also remain poorly constrained. In this data brief, we report U-Pb zircon ages from sandstones of the Rocas Verdes basin fill and from a crosscutting pluton in the southernmost Andes of Argentine Tierra del Fuego. Detrital samples contain predominant Early to early Middle Cretaceous (circa 130-105 Ma) U-Pb zircon age populations, with very small or single-grain middle Mesozoic and Proterozoic subpopulations. A very small subpopulation of Late Cretaceous ages in one sample raises the unlikely possibility that parts of the Rocas Verdes basin are younger than perceived. A sample from a crosscutting syenitic pegmatite yields a crystallization age of 74.7 +2.2/-2.0 Ma. The data presented herein encourage further geochronologic evaluation of the Rocas Verdes basin in order to better constrain the depositional ages and provenance of its contents.

  1. Use of Polyethylene Passive Samplers to Estimate Dissolved Phase PCBs in the Water Column of the Palos Verdes Superfund Site

    EPA Science Inventory

    The Palos Verdes Superfund site is located in over 50 meters of water on the continental shelf and slope off the coast of southern California (USA). The site includes 27 km2 of seabed contaminated over several decades by municipal treatment plant effluent discharged via outfall ...

  2. 75 FR 8149 - Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3 Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption...

  3. Evaluation of Polyethylene Passive Samplers to Estimate Deep Water PCB Concentrations at the Palos Verdes Shelf Superfund Site

    EPA Science Inventory

    The Palos Verdes Superfund site is located in over 50 meters of water on the continental shelf and slope off the coast of southern California (USA). The site includes 27 km2 of seabed contaminated over several decades by municipal treatment plant effluent discharged via outfall ...

  4. Comparison of cotton square and boll damage and resulting lint and seed loss caused by verde plant bug, Creontiades signatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Retention of bolls and squares (referred to as fruit retention), boll damage, and resulting cotton lint and seed weight loss were assessed when two (2010) and three (2011) age classes of sympodial fruiting branches with different ages of squares and bolls where exposed to verde plant bug, Creontiade...

  5. Cape Verde and Its People: A Short History, Part I [And] Folk Tales of the Cape Verdean People.

    ERIC Educational Resources Information Center

    Almeida, Raymond A.; Nyhan, Patricia

    Two booklets provide an overview of the history and folklore of Cape Verde, a group of islands lying 370 miles off the west coast of Africa. One booklet describes the history of the islands which were probably settled initially by Africans from the west coast of Africa. By the 15th century the islands were colonized by Portuguese and other…

  6. Verde plant bug (Hemiptera: Miridae) feeding injury to cotton bolls charcterized by boll age, size and damage ratings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our studies over 2 years (2009 and 2010) and 2 locations (Weslaco and Corpus Christi, TX) investigated the relationship of feeding-injury of the verde plant bug, Creontiades signatus Distant, to a range of cotton boll age classes further defined by boll diameter and accumulated degree-days (anthesis...

  7. Factors controlling the rate of DDE dechlorination to DDMU in Palos Verdes margin sediments under anaerobic conditions.

    PubMed

    Quensen, J F; Tiedje, J M; Jain, M K; Mueller, S A

    2001-01-15

    Marine sediments off the coast of the Palos Verdes Peninsula in California have been designated a Superfund site primarily because of the presence of DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethene]. For decades, it was believed that DDE was not microbially transformed, but anaerobic bacteria in the Palos Verdes sediments reductively dechlorinate DDEto DDMU [1-chloro-2,2-bis(p-chlorophenyl)ethene], which is also found in the sediments. The effects of electron donor to sulfate ratio, available carbon, sampling sites, sediment depth, and temperature on the rate and extent of DDE dechlorination in anaerobic Palos Verdes sediment microcosms were investigated. Dechlorination rates varied, depending on the site and depth from which the sediments were collected, but DDE dechlorination occurred with sediments from all locations studied. Sulfate and low temperatures slowed dechlorination, but in the presence of sulfate and at in situ temperature, the dechlorination rates observed in the microcosms agree well with the observed rate of DDE disappearance from the Palos Verdes margin sediments. PMID:11347599

  8. The Brava seamount, Cape Verde: Beyond the spatial extent of EM1 and petrogenesis of highly evolved alkaline lavas.

    NASA Astrophysics Data System (ADS)

    Barker, Abigail; Andersson, Axel; Troll, Valentin; Hansteen, Thor; Ellam, Robert

    2010-05-01

    Alkaline lavas from the Brava seamount, Cape Verde are investigated to establish the spatial distribution of compositional heterogeneity in the southwest of the Cape Verde archipelago. Highly evolved lavas provide a record of shallow level magma-crust interaction beneath the Brava seamount. The Brava seamount, located southwest of the island of Brava, Cape Verde was sampled during research cruise 8/85 of the R.R.S. Charles Darwin in 1985. Two groups of highly evolved alkaline volcanics are distinguished from the Brava seamount: 1) pyroxene-phonolites containing clinopyroxene, amphibole, nepheline, ±biotite, and minor sanidine and 2) feldspathoid-phonolites containing nepheline, nausean, minor biotite and leucite. All of the samples have MgO between 0.8 and 2 wt%, comparable to the most evolved volcanics sampled in the Cape Verde archipelago. The feldspathoid-phonolites have NaO2 of 12-13 wt%. Alkaline lavas from the Brava seamount have higher 87Sr/87Sr (0.70337 to 0.70347) at ɛNd of +6 to +7 than previously sampled in Cape Verde. Sr isotopes will be integrated with oxygen isotopes to establish magma and crust interactions in the magmatic plumbing system beneath the Brava seamount. Clinopyroxene-melt thermobarometry will be presented to constrain the depths of equilibrium crystallisation. Sr-O isotopes and thermobarometry will be combined to build a picture of the levels of magma stalling and interaction between magmas and the crust beneath the Brava seamount. The Brava seamount phonolitic lavas have high 206Pb/204Pb of 19.5 to 19.8 with negative ?8/4 and high ɛNd of +6 to +7 in contrast to the positive ?8/4 for lavas from nearby Brava and the southern islands of the Cape Verde archipelago. Lavas from the Brava seamount have Pb-Nd isotope systematics comparable to the northern Cape Verde islands, indicating the southwestern boundary in mantle heterogeneity and thereby the spatial extent of the EM1-like source contributing to the southern islands. The extensive

  9. Chemistry of Hot Spring Pool Waters in Calamba and Los Banos and Potential Effect on the Water Quality of Laguna De Bay

    NASA Astrophysics Data System (ADS)

    Balangue, M. I. R. D.; Pena, M. A. Z.; Siringan, F. P.; Jago-on, K. A. B.; Lloren, R. B.; Taniguchi, M.

    2014-12-01

    Since the Spanish Period (1600s), natural hot spring waters have been harnessed for balneological purposes in the municipalities of Calamba and Los Banos, Laguna, south of Metro Manila. There are at more than a hundred hot spring resorts in Brgy. Pansol, Calamba and Tadlac, Los Banos. These two areas are found at the northern flanks of Mt. Makiling facing Laguna de Bay. This study aims to provide some insights on the physical and chemical characteristics of hot spring resorts and the possible impact on the lake water quality resulting from the disposal of used water. Initial ocular survey of the resorts showed that temperature of the pool water ranges from ambient (>300C) to as high as 500C with an average pool size of 80m3. Water samples were collected from a natural hot spring and pumped well in Los Banos and another pumped well in Pansol to determine the chemistry. The field pH ranges from 6.65 to 6.87 (Pansol springs). Cation analysis revealed that the thermal waters belonged to the Na-K-Cl-HCO3 type with some trace amount of heavy metals. Methods for waste water disposal are either by direct discharge down the drain of the pool or by discharge in the public road canal. Both methods will dump the waste water directly into Laguna de Bay. Taking in consideration the large volume of waste water used especially during the peak season, the effect on the lake water quality would be significant. It is therefore imperative for the environmental authorities in Laguna to regulate and monitor the chemistry of discharges from the pool to protect both the lake water as well as groundwater quality.

  10. A Follow-up Study of Graduates of Laguna-Acoma High School Who Took ACT and/or Entered a Four-Year College Program.

    ERIC Educational Resources Information Center

    Munro, Fern H.

    The myth that only the high school student who is at or near the top of his class can succeed at a four-year college is not upheld for graduates of Laguna-Acoma High School (LAHS) in New Mexico. Many sources provide accurate gradepoint averages (GPA), American College Test (ACT) scores and Rank in Class (RIC) for the LAHS students who took the ACT…

  11. Chronologic implications of new Miocene mammals from the Cura-Mallín and Trapa Trapa formations, Laguna del Laja area, south central Chile

    NASA Astrophysics Data System (ADS)

    Flynn, John J.; Charrier, Reynaldo; Croft, Darin A.; Gans, Phillip B.; Herriott, Trystan M.; Wertheim, Jill A.; Wyss, André R.

    2008-12-01

    Recent work in the central Andean Main Range of Chile near Laguna del Laja (˜37.5°S, 71°W) has produced the first mammal fossils for the region. Fossils, locally abundant and well preserved, occur patchily across a wide area southeast of the lake. Mammalian remains are derived from generally strongly folded (kilometer-scale) exposures of the locally ˜1.8 km thick, early to middle Miocene Cura-Mallín Formation; two identifiable specimens have been recovered from the overlying Trapa Trapa Formation as well. Both formations consist primarily of well-stratified (1-5 m thick layers) volcaniclastic and volcanic strata, deposited predominantly in fluviatile systems. The Cura-Mallín Formation is possibly the southern continuation of (or lateral equivalent to) the richly fossiliferous Abanico Formation mapped between ˜32°S and 36°S. Intensive sampling in a series of localities east and south of Laguna del Laja has yielded diverse faunas, in addition to radioisotopically dateable horizons. The new fossil mammal faunas represent as many as six South American Land Mammal "Ages" (SALMAs). Fossils, together with preliminary 40Ar/ 39Ar radioisotopic dates, ranging from ˜9 to 20 Ma across the exposed thickness of the Cura-Mallín Formation and into the overlying Trapa Trapa Formation, provide a robust geochronological framework for middle Cenozoic strata in the Laguna del Laja region. The sequence of directly superposed mammalian assemblages at Laguna del Laja is one of the longest in all of South America, rivaled only by the classic Gran Barranca section of Patagonian Argentina. These data illuminate the geological history of the area and its record of mammalian evolution. The potential to isotopically date these diverse faunas with high precision (error ± 0.5 Ma) presents a rare opportunity to calibrate related portions of the SALMA sequence.

  12. Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.

    PubMed

    Herrera, Christian; Custodio, Emilio; Chong, Guillermo; Lambán, Luis Javier; Riquelme, Rodrigo; Wilke, Hans; Jódar, Jorge; Urrutia, Javier; Urqueta, Harry; Sarmiento, Alvaro; Gamboa, Carolina; Lictevout, Elisabeth

    2016-01-15

    Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water-rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ(18)O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. PMID:26410705

  13. Sulphur dioxide (SO2) emissions during the 2014-15 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Barrancos, José; Dionis, Samara; Quevedo, Roberto; Fernandes, Paulo; Rodríguez, Fátima; Pérez, Nemesio M.; Silva, Sónia; Cardoso, Nadir; Hernández, Pedro A.; Melián, Gladys V.; Padrón, Eleazar; Padilla, Germán; Asensio-Ramos, María; Calvo, David; Semedo, Helio; Alfama, Vera

    2015-04-01

    A new eruption started at Fogo volcanic island on November 23, 2014, an active stratovolcano, located in the SW of the Cape Verde Archipelago; rising over 6 km from the 4000m deep seafloor to the Pico do Fogo summit at 2829m above sea level (m.a.s.l.). Since settlement in the 15th century, 27 eruptions have been identified through analysis of incomplete written records (Ribeiro, 1960), with average time intervals of 20 yr and average duration of two months. The eruptions were mostly effusive (Hawaiian to Strombolian), with rare occurrences of highly explosive episodes including phreatomagmatic events (Day et al., 1999). This study reports sulphur dioxide (SO2) emission rate variations observed throughout the 2014-15 Fogo eruption, Cape Verde. More than 100 measurements of SO2 emission rate have been carried out in a daily basis by ITER/INVOLCAN/UNICV/OVCV/SNPC research team since November 28, 2014, five days after the eruption onset, by means of a miniDOAS using the traverse method with a car. The daily deviation obtained of the data is around 15%. Estimated SO2 emission rates ranged from 12,476 ± 981 to 492 ± 27 tons/day during the 2014-15 Fogo eruption until January 1, 2015. During this first five days of measurements, the observed SO2 emission rates were high with an average rate of 11,100 tons/day. On December 3, 2014 the SO2 emission rate dropped to values close to 4,000 tons/day, whereas few days later, on December 10, 2014, an increase to values close to 11,000 tons/day was recorded. Since then, SO2 emission rate has shown decrease trend to values close to 1,300 tons/day until December 21, 2014. The average of the observed SO2 emission rate was about 2,000 tons/day from December 21, 2014 to January 1, 2015, without detecting a specific either increasing or decreasing trend of the SO2 emission rate. The objective of this report is to clarify relations between the SO2 emission rate and surface eruptive activity during the 2014-15 Fogo eruption. Day, S. J

  14. Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

    USGS Publications Warehouse

    Carrara, Paul E.

    2012-01-01

    Mesa Verde National Park in southwestern Colorado was established in 1906 to preserve and protect the artifacts and dwelling sites, including the famous cliff dwellings, of the Ancestral Puebloan people who lived in the area from about A.D. 550 to A.D. 1300. In 1978, the United Nations designated the park as a World Heritage Site. The geology of the park played a key role in the lives of these ancient people. For example, the numerous (approximately 600) cliff dwellings are closely associated with the Cliff House Sandstone of Late Cretaceous age, which weathers to form deep alcoves. In addition, the ancient people farmed the thick, red loess (wind-blown dust) deposits on the mesa tops, which because of its particle size distribution has good moisture retention properties. The soil in this loess cover and the seasonal rains allowed these people to grow their crops (corn, beans, and squash) on the broad mesa tops. Today, geology is still an important concern in the Mesa Verde area because the landscape is susceptible to various forms of mass movement (landslides, debris flows, rockfalls), swelling soils, and flash floods that affect the park's archeological sites and its infrastructure (roads, septic systems, utilities, and building sites). The map, which encompasses an area of about 100 mi2 (260 km2), includes all of Mesa Verde National Park, a small part of the Ute Mountain Indian Reservation that borders the park on its southern and western sides, and some Bureau of Land Management and privately owned land to the north and east. Surficial deposits depicted on the map include: artificial fills, alluvium of small ephemeral streams, alluvium deposited by the Mancos River, residual gravel on high mesas, a combination of alluvial and colluvial deposits, fan deposits, colluvial deposits derived from the Menefee Formation, colluvial deposits derived from the Mancos Shale, rockfall deposits, debris flow deposits, earthflow deposits, translational and rotational landslide

  15. Cohesive Sediment Erodibility and Evolution of a Mud Deposit on the Palos Verdes Shelf

    NASA Astrophysics Data System (ADS)

    Sherwood, C. R.; Ferre, B.; Murray, C. J.; Sanford, L. P.; Warner, J. C.; Wiberg, P. L.

    2006-12-01

    We have added a cohesive-sediment erodibility algorithm to ROMS, a three-dimensional numerical model for circulation and sediment transport. The new code implements an algorithm developed by Sanford ("Modeling a dynamically varying mixed sediment bed with erosion, deposition, bioturbation, consolidation, and armoring", Computers and Geosciences, in review.) The algorithm assumes that cohesive sediment has a critical stress for erosion that varies (typically increasing) with depth in the sediment, determined by various physical and biological properties or processes. Erosion and deposition alter this profile, but it is reestablished over a characteristic time scale which is longer than typical resuspension events (a few days) but probably less than a year. The critical stress profile limits the amount of sediment that can be eroded during to the mass available at the maximum stress applied during the event. Because the critical stress profile varies with time, the response to events depends on the history of sediment disturbance and recovery. The shapes of the critical stress profiles can vary both horizontally and vertically. In this pilot application, the shapes of the profiles were determined from geostatistical modeling of field data collected on a mud deposit on the Palos Verdes Shelf off Los Angeles. The data include about 30 traditional grain-size measurements, 10 erosion-chamber experiments, and 160 measurements of the penetration depths of a sediment-profiling camera. The penetration depths were highly correlated (r=0.84) with the slope of the erodibility profiles determined by the erosion chamber. Maps of erodibility (i.e., slope and offset of the critical stress profiles) on the Palos Verdes Shelf were made with Gaussian simulation and collocated cokriging of the erosion-chamber data conditioned on the camera-penetration data. These and maps of bottom grain-size distribution were used to initialize the bed sediment in ROMS. Model runs were made for the

  16. Identifying wells downstream from Laguna Dam that yield water that will be replaced by water from the Colorado River, Arizona and California

    USGS Publications Warehouse

    Owen-Joyce, Sandra J.

    2000-01-01

    This report summarizes a comprehensive study and development of the method documented in Owen-Joyce and others (2000). That report and one for the area upstream from Laguna Dam (Wilson and Owen-Joyce, 1994) document the accounting-surface method to identify wells that yield water that will be replaced by water from the Colorado River. Downstream from Laguna Dam, the Colorado River is the source for nearly all recharge to the river aquifer. The complex surface-water and ground-water system that exists in the area is, in part, the result of more than 100 years of water-resources development. Agriculture is the principal economy and is possible only with irrigation. The construction and operation of canals provides the means to divert and distribute Colorado River water to irrigate agricultural lands on the flood plains and mesas along the Colorado and Gila Rivers, in Imperial and Coachella Valleys, and in the area upstream from Dome along the Gila River. Water is withdrawn from wells for irrigation, dewatering, and domestic use. The area downstream from Laguna Dam borders additional areas of agricultural development in Mexico where Colorado River water also is diverted for irrigation.

  17. Identification and dating of indigenous water storage reservoirs along the Rio San José at Laguna Pueblo, western New Mexico, USA

    USGS Publications Warehouse

    Huckleberry, Gary; Ferguson, T.J.; Rittenour, Tammy M.; Banet, Chris; Mahan, Shannon

    2016-01-01

    An investigation into indigenous water storage on the Rio San José in western New Mexico was conducted in support of efforts by the Pueblo of Laguna to adjudicate their water rights. Here we focus on stratigraphy and geochronology of two Native American-constructed reservoirs. One reservoir located near the community of Casa Blanca was formed by a ∼600 m (2000 feet) long stone masonry dam that impounded ∼1.6 × 106 m3 (∼1300 acre-feet) of stored water. Four optically stimulated luminescence (OSL) ages obtained on reservoir deposits indicate that the dam was constructed prior to AD 1825. The other reservoir is located adjacent to Old Laguna Pueblo and contains only a small remnant of its former earthen dam. The depth and distribution of reservoir deposits and a photogrammetric analyses of relict shorelines indicate a storage capacity of ∼6.5 × 106 m3 (∼5300 ac-ft). OSL ages from above and below the base of the reservoir indicate that the reservoir was constructed sometime after AD 1370 but before AD 1750. The results of our investigation are consistent with Laguna oral history and Spanish accounts demonstrating indigenous construction of significant water-storage reservoirs on the Rio San José prior to the late nineteenth century.

  18. The Vida Verde Women's Co-Op: Brazilian immigrants organizing to promote environmental and social justice.

    PubMed

    Gute, David M; Siqueira, Eduardo; Goldberg, Julia S; Galvão, Heloisa; Chianelli, Mônica; Pirie, Alex

    2009-11-01

    We reviewed the key steps in the launch of the Vida Verde Women's Co-Op among Brazilian immigrant housecleaners in Somerville, MA. The co-op provides green housecleaning products, encourages healthy work practices, and promotes a sense of community among its members. We conducted in-depth interviews with 8 of the first co-op members, who reported a reduction in symptoms associated with the use of traditional cleaning agents and a new sense of mutual support. Critical to the co-op's success have been the supportive roles of its academic partners (Tufts University and the University of Massachusetts, Lowell), effective media outreach, and a focus on advancing social justice. Next steps include implementing a formal business plan and assessing the appropriateness of cooperatives in other industries. PMID:19890146

  19. [An attractive force: the meaning of drugs to users from an island in Cape Verde].

    PubMed

    Neves, Augusto César Lima; Miasso, Adriana Inocenti

    2010-01-01

    This qualitative study aimed to understand the meaning of drug consumption from the view of users who receive care in an outpatient clinic of a Mental Health Service on an island of the Cape Verde archipelago. The methodological framework was based on the Data-founded Theory, in the light of Symbolic Interactionism. Participants were nine drug users from the mentioned outpatient clinic. Recorded interviews and observation were the strategies for data collection. The comparative data analysis resulted in the central phenomenon An attractive force, which expresses the great difficult users have to stop the abusive consumption of psychoactive substances, knowing that all problems faced in the personal, familiar and social areas come from drug habituation. Thus, this study permitted the identification of vulnerable points for possible action by the health team, aiming for the prevention of drug abuse. PMID:20694429

  20. Val Verde Basin: Thrusted Strawn (Pennsylvanian) carbonate reservoirs, Pakenham Field area

    SciTech Connect

    Montgomery, S.L.

    1996-07-01

    An important target of recent exploration in the Val Verde basin of southwestern Texas has been thrusted Pennsylvanian (Desmoinesian) carbonates along the leading edge of the Ouachita front. These reservoirs produce gas and condensate at significant rates from fractured limestones, which were deposited in a variety of environments and later complexly juxtaposed during thrusting. Improvements in seismic imaging capabilities, particularly associated with the introduction of two-dimension (2-D) swath and three-dimensional (3-D) surveys, have allowed accurate mapping of the thrust front and have resulted in revised interpretations of basin structure and history. These data highlight the existence of multiple reservoirs at separate structural levels. Strawn reservoirs are discussed in relation to the Pakenham field area, northwestern Terrell County.

  1. Condom use at last sexual relationship among adolescents of Santiago Island, Cape Verde, - West Africa

    PubMed Central

    2012-01-01

    Objective To estimate factors associated with condom use at last sexual intercourse among adolescents. Methods Cross-sectional study of a representative sample of 368 sexually active adolescents aged 13–17 years from eight public high schools on Santiago Island, Cape Verde, 2007. The level of significance was 5.0% obtained from logistic regression, considering the association between condom use and socio-demographic, sexual and reproductive variables. Results The prevalence of condom use at last sexual intercourse was 94.9%. Factors associated with condom use at last sexual relationship were: non-Catholic religion (OR=0.68, 95%CI: 0.52; 0.88) and affective-sexual partnership before the interview (OR=5.15, 95%CI: 1.79; 14.80). Conclusions There was a high prevalence of condom use at last sexual intercourse of adolescents. PMID:23153259

  2. Problems plague startup of Palo Verde nukes: NRC proposes fines for QA deficiencies, records falsification

    SciTech Connect

    Not Available

    1984-01-01

    Defective coolant pump design in unit one and a failure to get adequate rate relief from the Arizona Corporation Commission to cover the 16% cost overruns are delaying commercial operation at Phoenix's Palo Verde nuclear plant. Arizona Public Service (APS) Company's deteriorating financial situation caused the utility to scrap a program to credit customers who purchase energy-saving devices and threatens more extreme action. The Nuclear Regulatory Commission fined APS for alleged quality assurance (QA) violations following a construction appraisal inspection at unit one and reports of falsified installation records. APS argues that its own inspectors would have found the missing bolts and the caps installed on pressure-sensing lines, but concedes the QA lapses. The company challenges NRC's report of a possible 150 falsifications, and concedes only one. The NRC imposes a $40,000 fine on each violation. (DCK)

  3. Better health data with a portable microcomputer at the periphery: an anthropometric survey in Cape Verde

    PubMed Central

    Reitmaier, P.; Dupret, A.; Cutting, W. A. M.

    1987-01-01

    A portable microcomputer was programmed to record anthropometric nutritional data from children aged under 7 years in either a clinic or a population survey situation. An alarm sounds when the anthropometric measurements of a child are below a predetermined value; an immediate check thus avoids the need for subsequent data cleaning and discarding of doubtful information. Data cut-off points in the computer can be adjusted to suit the survey or service needs of the situation. A print-out at the end of the clinic session provides immediate feedback for the staff and a record of the nutritional status of the group. In Cape Verde, 14 670 children attending clinics were surveyed; 26% were identified as stunted, 3% as wasted, and 1% as stunted and wasted. While a portable microcomputer can improve precision, speed and motivation, nutrition surveys still depend on accurate scales, careful measurements and competent staff. ImagesFig. 1 PMID:3322601

  4. Geostatistical mapping of effluent-affected sediment distribution on the Palos Verdes Shelf

    SciTech Connect

    Murray, Christopher J. ); Lee, H J.; Hampton, M A.

    2001-12-01

    Geostatistical techniques were used to study the spatial continuity of the thickness of effluent-affected sediment in the offshore Palos Verdes margin area. The thickness data were measured directly from cores and indirectly from high-frequency subbottom profiles collected over the Palos Verdes Margin. Strong spatial continuity of the sediment thickness data was identified, with a maximum range of correlation in excess of 1.4 km. The spatial correlation showed a marked anisotropy, and was more than twice as continuous in the alongshore direction as in the cross-shelf direction. Sequential indicator simulation employing models fit to the thickness data variograms was used to map the distribution of the sediment, and to quantify the uncertainty in those estimates. A strong correlation between sediment thickness data and measurements of the mass of the contaminant p,p?-DDE per unit area was identified. A calibration based on the bivariate distribution of the thickness and p,p?-DDE data was applied using Markov-Bayes indicator simulation to extend the geostatistical study and map the contamination levels in the sediment. Integrating the map grids produced by the geostatistical study of the two variables indicated that 7.8 million cubic meters of effluent-affected sediment exist in the map area, containing approximately 61 to 72 Mg (metric tons) of p,p?-DDE. Most of the contaminated sediment (about 85% of the sediment and 89% of the p,p?-DDE) occurs in water depths less than 100 m. The geostatistical study also indicated that the samples available for mapping are well distributed and the uncertainty of the estimates of the thickness and contamination level of the sediments is lowest in areas where the contaminated sediment is most prevalent.

  5. Depositional characteristics of middle to upper Miocene Point Fermin Submarine Fan, Palos Verdes, California

    SciTech Connect

    Russell, P.W.

    1987-05-01

    The Point Fermin submarine fan lies within the upper Monterey Formation of the Palos Verdes Peninsula, California. Exposures of sediment gravity flow deposits extend from the upper portion of the tuffaceous lithofacies of the Altamira shale member to the middle of the Valmonte Diatomite. Outstanding sea-cliff exposures display a three-dimensional view of a large (approximately 1000 ft across) backfilled channel, scoured into thin-bedded shale and sandstone deposits. Channel backfill deposits primarily consist of Catalina schist-bearing sandstone and breccia, and lenses of disorganized intraformational breccia and conglomerate. The exposures exhibit an overall thinning and fining-upward sequence. The coarse-grained basal portion of the sequence displays sedimentary structures and bedding characteristics which are indicative of mass deposition by extremely concentrated, viscous dispersions. Channelized breccia beds contain schist clasts up to 9 ft in diameter, and intraformation breccia lenses contain rip-up clasts of Monterey Shale up to 30 ft long. Inferred flow mechanisms are a combination of grain flow, high-density turbulent flow, and sandy debris flow. The coarseness of these deposits is indicative of a proximal source. Higher in the sequence, sedimentary structures in upper portions of individual beds are characteristic of low-density turbulent flows. This upward change in sedimentary structures within individual beds is indicative of the passage of a high-density gravity flow and the subsequent waning, low-density turbulent flow conditions which follow. Directional features indicate a mean southeasterly flow direction. These results (which contradict data from previous published reports), in conjunction with the overall coarseness of these deposits, suggest the source to be the Palos Verde uplift.

  6. Tracking effusive eruptions in near real-time: 2014 Fogo (Cape Verde) eruption

    NASA Astrophysics Data System (ADS)

    Laiolo, Marco; Coppola, Diego; Cigolini, Corrado; Faria, Bruno; Ripepe, Maurizio

    2015-04-01

    The Fogo volcano (Cape Verde), after almost 20 years of inactivity, entered in a new effusive phase on November 23, 2014. The eruption occurred on the Fogo's Pico cone inside the Cha Caldera where the lava flow caused the evacuation of the Bangaeira and Portela inhabitants. To track the thermal evolution of this eruption, we extended the near-real time processing of the MIROVA (Middle InfraRed Observation of Volcanic Activity) algorithm to Fogo island. MIROVA is a hot-spot detection system based on the analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) data that provide thermal maps (1 km resolution) and radiant flux estimates, in near real time (1-4 hours from satellite overpass). Thermal output retrieved by MIROVA can be converted into time-average lava discharge rates allowing the identification of ongoing effusive trends. During the first 45 days of activity the eruption shows a waxing-waning trend typical of pressurized closed systems. Preliminary results indicate that MIROVA is particularly efficient to provide near real-time data that are critical for better assessing volcanic risk, and to help the decision-makers during volcanic crisis. Data requested by the UNDAC (United Nations Disaster Assessment and Coordination) team operating in Cape Verde, through the Emergency Response Coordination Center (ERCC) of the European Mechanism of Civil Protection, were provided in near real-time via web to the National Institute of Meteorology and Geophysics and to National Civil Protection. Once compared to seismological data, information provided by MIROVA have been successfully used during the volcanic crisis.

  7. Evapotranspiration estimates using remote-sensing data, Parker and Palo Verde valleys, Arizona and California

    USGS Publications Warehouse

    Raymond, L.H.; Rezin, K.V.

    1986-01-01

    In 1981 the U.S. Geological Survey established an experimental project to assess the possible and practical use of remote sensing data to estimate evapotranspiration as an approximation of consumptive use in the lower Colorado River flood plain. The project area was in Parker Valley, Arizona. The approach selected was to measure the areas covered by each type of vegetation using remote sensing data in various types of analyses and to multiply each area by a predetermined water use rate. Two calibration and six remote sensing methods of classifying crop types were compared for cost, accuracy, consistency, and labor requirements. Included were one method each for field reconnaissance using 1982 data, low altitude (< than 5,000 ft) aerial photography using 1982 data, and visual photointerpretation of Landsat satellite images using 1981 and 1982 data; two methods for medium-altitude (15,000-18,000 ft) aerial photography using 1982 data; and three methods for digital Landsat satellite images using 1981 data. A test of the most promising digital processing method, which used three image dates, was made in part of Palo Verde Valley, California, where 1981 crop data were more complete than in Parker Valley. Of the eight methods studied, the three-date digital processing method was the most consistent and least labor-intensive; visual photointerpretation of Landsat images was the least expensive. Evapotranspiration estimates from crop classifications by all methods differed by a maximum of 6%. Total evapotranspiration calculated from crop data and phreatophyte maps in 1981 ranged from 12% lower in Palo Verde Valley to 17% lower in Parker Valley than consumptive use calculated by water budgets. The difference was greater in Parker Valley because the winter crop data were not included. (Author 's abstract)

  8. Preliminary report on geophysics of the Verde River headwaters region, Arizona

    USGS Publications Warehouse

    Langenheim, V.E.; Duval, J.S.; Wirt, Laurie; DeWitt, Ed

    2000-01-01

    This report summarizes the acquisition, data processing, and preliminary interpretation of a high-resolution aeromagnetic and radiometric survey near the confluence of the Big and Little Chino basins in the headwaters of the Verde River, Arizona. The goal of the aeromagnetic study is to improve understanding of the geologic framework as it affects groundwater flow, particularly in relation to the occurrence of springs in the upper Verde River headwaters region. Radiometric data were also collected to map surficial rocks and soils, thus aiding geologic mapping of the basin fill. Additional gravity data were collected to enhance existing coverage. Both aeromagnetic and gravity data indicate a large gradient along the Big Chino fault, a fault with Quaternary movement. Filtered aeromagnetic data show other possible faults within the basin fill and areas where volcanic rocks are shallowly buried. Gravity lows associated with Big Chino and Williamson Valleys indicate potentially significant accumulations of low-density basin fill. The absence of a gravity low associated with Little Chino Valley indicates that high-density rocks are shallow. The radiometric maps show higher radioactivity associated with the Tertiary latites and with the sediments derived from them. The surficial materials on the eastern side of the Big Chino Valley are significantly lower in radioactivity and reflect the materials derived from the limestone and basalt east of the valley. The dividing line between the low radioactivity materials to the east and the higher radioactiviy materials to the west coincides approximately with the major drainage system of the valley, locally known as Big Chino Wash. This feature is remarkably straight and is approximately parallel to the Big Chino Fault. The uranium map shows large areas with concentrations greater than 5 ppm eU, and we expect that these areas will have a significantly higher risk potential for indoor radon.

  9. Evapotranspiration estimates using remote-sensing data, Parker and Palo Verde valleys, Arizona and California

    USGS Publications Warehouse

    Raymond, Lee H.; Rezin, Kelly V.

    1989-01-01

    In 1981 the U.S. Geological Survey established an experimental project to assess the possible and practical use of remote-sensing data to estimate evapotranspiration as an approximation of consumptive use of water in the lower Colorado River flood plain. The project area was in Parker Valley, Arizona. The approach selected was to measure the areas covered by each type of vegetation, using remote-sensing data in various types of analyses, and to multiply each area by a predetermined water-use rate. Two calibration and six remote-sensing methods of classifying crop types were compared for cost, accuracy, consistency, and labor requirements. Included were one method each for field reconnaissance using 1982 data, low-altitude (less than 5,000 feet) aerial photography using 1982 data, and visual photointerpretation of Landsat satellite images using 1981 and 1982 data; two methods for medium-altitude (15,000-18,000 feet) aerial photography using 1982 data; and three methods for digital Landsat satellite images using 1981 data. A test of the most promising digital-processing method, which used three image dates, was made in part of Palo Verde Valley, California, where 1981 crop data were more complete than in Parker Valley. Of the eight methods studied, the two-date digital-processing method was the most consistent and least labor intensive for identifying two or three major crops; visual photointerpretation of Landsat images was the least expensive. Evapotranspiration estimates from crop classifications by all methods differed by a maximum of 6 percent. Total evapotranspiration calculated from crop data and phreatophyte maps in 1981 ranged from 11 percent lower in Palo Verde Valley to 17 percent lower in Parker Valley than consumptive use calculated by water budgets. The difference was greater in Parker Valley because the winter crop data were not included.

  10. Intraplate seismicity across the Cape Verde swell: A contribution from a temporary seismic network

    NASA Astrophysics Data System (ADS)

    Vales, Dina; Dias, Nuno A.; Rio, Inês; Matias, Luís; Silveira, Graça; Madeira, José; Weber, Michael; Carrilho, Fernando; Haberland, Christian

    2014-12-01

    We present an analysis and characterization of the regional seismicity recorded by a temporary broadband seismic network deployed in the Cape Verde archipelago between November 2007 and September 2008. The detection of earthquakes was based on spectrograms, allowing the discrimination from low-frequency volcanic signals, resulting in 358 events of which 265 were located, the magnitudes usually being smaller than 3. For the location, a new 1-D P-velocity model was derived for the region showing a crust consistent with an oceanic crustal structure. The seismicity is located mostly offshore the westernmost and geologically youngest areas of the archipelago, near the islands of Santo Antão and São Vicente in the NW and Brava and Fogo in the SW. The SW cluster has a lower occurrence rate and corresponds to seismicity concentrated mainly along an alignment between Brava and the Cadamosto seamount presenting normal faulting mechanisms. The existence of the NW cluster, located offshore SW of Santo Antão, was so far unknown and concentrates around a recently recognized submarine cone field; this cluster presents focal depths extending from the crust to the upper mantle and suggests volcanic unrest. No evident temporal behaviour could be perceived, although the events tend to occur in bursts of activity lasting a few days. In this recording period, no significant activity was detected at Fogo volcano, the most active volcanic edifice in Cape Verde. The seismicity characteristics point mainly to a volcanic origin. The correlation of the recorded seismicity with active volcanic structures agrees with the tendency for a westward migration of volcanic activity in the archipelago as indicated by the geologic record.

  11. Heavy minerals from the Palos Verdes Margin, Southern California: data and actor analysis

    USGS Publications Warehouse

    Wong, Florence L.

    2001-01-01

    Heavy or high-density minerals in the 63-250-_m (micron) size fraction (very fine and fine sand) were analyzed from 36 beach and offshore sites (38 samples) of the Palos Verdes margin to determine the areal and temporal mineralogic distributions and the relation of those distributions to the deposit affected by material discharged from the Los Angeles County Sanitation District sewage system (Lee, 1994) (Figure 1). Data presented here were tabulated for a report to the Department of Justice (Wong, 1994). The results of the data analysis are discussed in Wong (in press). The study of heavy minerals is a common method of determining sources (provenance) and distributions of sediments (e.g., Van Andel and Poole, 1960). The choice of grain size is governed by ease of sample preparation, examination by optical microscopy, and comparability to previous studies. How representative the 63-250-_m heavy minerals are of the whole sample can be approximated by the amount of sand in the sample. Lee and others (1994) mapped a pre-effluent, effluent-affected, and surface layer in the study area off Palos Verdes. The amount of sand in the top and pre-effluent layers ranges from about 20 to 80 percent; in the middle of the effluent body, sand is less than 20 percent (Figure 2; MacArthur and others, 1994). Qualitatively, the 63-250-_m heavy minerals are more representative of the top and pre-effluent layer, but these minerals will also provide useful information about the middle layer.

  12. Linking microbial assemblages to paleoenvironmental conditions from the Holocene and Last Glacial Maximum times in Laguna Potrok Aike sediments, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, Aurele; Ariztegui, Daniel; Leavitt, Peter R.; Bunting, Lynda

    2014-05-01

    Laguna Potrok Aike is a closed basin located in the southern hemisphere's mid-latitudes (52°S) where paleoenvironmental conditions were recorded as temporal sedimentary sequences resulting from variations in the regional hydrological regime and geology of the catchment. The interpretation of the limnogeological multiproxy record developed during the ICDP-PASADO project allowed the identification of contrasting time windows associated with the fluctuations of Southern Westerly Winds. In the framework of this project, a 100-m-long core was also dedicated to a detailed geomicrobiological study which aimed at a thorough investigation of the lacustrine subsurface biosphere. Indeed, aquatic sediments do not only record past climatic conditions, but also provide a wide range of ecological niches for microbes. In this context, the influence of environmental features upon microbial development and survival remained still unexplored for the deep lacustrine realm. Therefore, we investigated living microbes throughout the sedimentary sequence using in situ ATP assays and DAPI cell count. These results, compiled with pore water analysis, SEM microscopy of authigenic concretions and methane and fatty acid biogeochemistry, provided evidence for a sustained microbial activity in deep sediments and pinpointed the substantial role of microbial processes in modifying initial organic and mineral fractions. Finally, because the genetic material associated with microorganisms can be preserved in sediments over millennia, we extracted environmental DNA from Laguna Potrok Aike sediments and established 16S rRNA bacterial and archaeal clone libraries to better define the use of DNA-based techniques in reconstructing past environments. We focused on two sedimentary horizons both displaying in situ microbial activity, respectively corresponding to the Holocene and Last Glacial Maximum periods. Sequences recovered from the productive Holocene record revealed a microbial community adapted to

  13. Lateglacial and Holocene climatic changes in south-eastern Patagonia inferred from carbonate isotope records of Laguna Potrok Aike (Argentina)

    NASA Astrophysics Data System (ADS)

    Oehlerich, M.; Mayr, C.; Gussone, N.; Hahn, A.; Hölzl, S.; Lücke, A.; Ohlendorf, C.; Rummel, S.; Teichert, B. M. A.; Zolitschka, B.

    2015-04-01

    First results of strontium, calcium, carbon and oxygen isotope analyses of bulk carbonates from a 106 m long sediment record of Laguna Potrok Aike, located in southern Patagonia are presented. Morphological and isotopic investigations of μm-sized carbonate crystals in the sediment reveal an endogenic origin for the entire Holocene. During this time period the calcium carbonate record of Laguna Potrok Aike turned out to be most likely ikaite-derived. As ikaite precipitation in nature has only been observed in a narrow temperature window between 0 and 7 °C, the respective carbonate oxygen isotope ratios serve as a proxy of hydrological variations rather than of palaeotemperatures. We suggest that oxygen isotope ratios are sensitive to changes of the lake water balance induced by intensity variations of the Southern Hemisphere Westerlies and discuss the role of this wind belt as a driver for climate change in southern South America. In combination with other proxy records the evolution of westerly wind intensities is reconstructed. Our data suggest that weak SHW prevailed during the Lateglacial and the early Holocene, interrupted by an interval with strengthened Westerlies between 13.4 and 11.3 ka cal BP. Wind strength increased at 9.2 ka cal BP and significantly intensified until 7.0 ka cal BP. Subsequently, the wind intensity diminished and stabilised to conditions similar to present day after a period of reduced evaporation during the "Little Ice Age". Strontium isotopes (87Sr/86Sr ratio) were identified as a potential lake-level indicator and point to a lowering from overflow conditions during the Glacial (∼17 ka cal BP) to lowest lake levels around 8 ka cal BP. Thereafter the strontium isotope curve resembles the lake-level curve which is stepwise rising until the "Little Ice Age". The variability of the Ca isotope composition of the sediment reflects changes in the Ca budget of the lake, indicating higher degrees of Ca utilisation during the period with

  14. Deep Drilling at Laguna Potrok Aike, Argentina: Recovery of a Paleoclimate Record for the Last Glacial from the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zolitschka, B.; Anselmetti, F.; Ariztegui, D.; Corbella, H.; Francus, P.; Gebhardt, C.; Hahn, A.; Kliem, P.; Lücke, A.; Ohlendorf, C.; Schäbitz, F.

    2009-12-01

    Laguna Potrok Aike, located in the South-Patagonian province of Santa Cruz (52°58’S, 70°23’W), was formed 770 ka ago by a volcanic (maar) eruption. Within the framework of the ICDP-funded project PASADO two sites were drilled from September to November 2008 using the GLAD800 drilling platform. A total of 513 m of lacustrine sediments were recovered from the central deep basin by an international team. The sediments hold a unique record of paleoclimatic and paleoecological variability from a region sensitive to variations in southern hemispheric wind and pressure systems and thus significant for the understanding of the global climate system. Moreover, Laguna Potrok Aike is close to many active volcanoes allowing a better understanding of the history of volcanism in the Pali Aike Volcanic Field and in the nearby Andean mountain chain. These challenging scientific themes need to be tackled in a global context as both are of increasing socio-economic relevance. On-site core logging based on magnetic susceptibility data documents an excellent correlation between the quadruplicate holes drilled at Site 1 and between the triplicate holes recovered from Site 2. Also, correlation between both sites located 700 m apart from each other is feasible. After splitting the cores in the lab, a reference profile was established down to a composite depth of 107 m for the replicate cores from Site 2. Sediments consist of laminated and sand-layered lacustrine silts with an increasing number of turbidites and homogenites with depth. Below 80 m composite depth two mass movement deposits (10 m and 5 m in thickness) are recorded. These deposits show tilted and distorted layers as well as nodules of fine grained sediments and randomly distributed gravel. Such features indicate an increased slump activity probably related to lake level fluctuations or seismicity. Also with depth coarse gravel layers are present and point to changes in hydrological conditions in the catchment area

  15. Analysis of the ecosystem structure of Laguna Alvarado, western Gulf of Mexico, by means of a mass balance model

    NASA Astrophysics Data System (ADS)

    Cruz-Escalona, V. H.; Arreguín-Sánchez, F.; Zetina-Rejón, M.

    2007-03-01

    Alvarado is one of the most productive estuary-lagoon systems in the Mexican Gulf of Mexico. It has great economic and ecological importance due to high fisheries productivity and because it serves as a nursery, feeding, and reproduction area for numerous populations of fishes and crustaceans. Because of this, extensive studies have focused on biology, ecology, fisheries (e.g. shrimp, oysters) and other biological components of the system during the last few decades. This study presents a mass-balanced trophic model for Laguna Alvarado to determine it's structure and functional form, and to compare it with similar coastal systems of the Gulf of Mexico and Mexican Pacific coast. The model, based on the software Ecopath with Ecosim, consists of eighteen fish groups, seven invertebrate groups, and one group each of sharks and rays, marine mammals, phytoplankton, sea grasses and detritus. The acceptability of the model is indicated by the pedigree index (0.5) which range from 0 to 1 based on the quality of input data. The highest trophic level was 3.6 for marine mammals and snappers. Total system throughput reached 2680 t km -2 year -1, of which total consumption made up 47%, respiratory flows made up 37% and flows to detritus made up 16%. The total system production was higher than consumption, and net primary production higher than respiration. The mean transfer efficiency was 13.8%. The mean trophic level of the catch was 2.3 and the primary production required to sustain the catch was estimated in 31 t km -2 yr -1. Ecosystem overhead was 2.4 times the ascendancy. Results suggest a balance between primary production and consumption. In contrast with other Mexican coastal lagoons, Laguna Alvarado differs strongly in relation to the primary source of energy; here the primary producers (seagrasses) are more important than detritus pathways. This fact can be interpreted a response to mangrove deforest, overfishing, etc. Future work might include the compilation of

  16. 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.

  17. Evolution of unrest at Laguna del Maule volcanic field (Chile) from InSAR and GPS measurements, 2003 to 2014

    NASA Astrophysics Data System (ADS)

    Le Mével, Hélène; Feigl, Kurt L.; Córdova, Loreto; DeMets, Charles; Lundgren, Paul

    2015-08-01

    The Laguna del Maule (LdM) volcanic field in the southern volcanic zone of the Chilean Andes exhibits a large volume of rhyolitic material erupted during postglacial times (20-2 ka). Since 2007, LdM has experienced an unrest episode characterized by high rates of deformation. Analysis of new GPS and Interferometric Synthetic Aperture Radar (InSAR) data reveals uplift rates greater than 190 mm/yr between January 2013 and November 2014. The geodetic data are modeled as an inflating sill at depth. The results are used to calculate the temporal evolution of the vertical displacement. The best time function for modeling the InSAR data set is a double exponential model with rates increasing from 2007 through 2010 and decreasing slowly since 2010. We hypothesize that magma intruding into an existing silicic magma reservoir is driving the surface deformation. Modeling historical uplift at Yellowstone, Long Valley, and Three Sisters volcanic fields suggests a common temporal evolution of vertical displacement rates.

  18. Impact of Hot Spring Resort Development on the Groundwater Discharge in the Southeast Part of Laguna De Bay, Luzon, Philippines

    NASA Astrophysics Data System (ADS)

    Siringan, F. P.; Lloren, R. B.; Mancenido, D. L. O.; Jago-on, K. A. B.; Pena, M. A. Z.; Balangue-Tarriela, M. I. R.; Taniguchi, M.

    2014-12-01

    Direct groundwater seepage in a lake (DGSL) can be a major component to its water and nutrient budget. Groundwater extraction around a lake may affect the DGSL, thus it can be expected that it would also impact the lake. In the Philippines, Laguna de Bay which is the second largest freshwater lake in South-east Asia and used primarily for fisheries, is under significant water development pressure. Along the southern coast of the lake, in the Calamba-Los Banos area, rapid urbanization and development of the water resort industry, including hot spring spas, are expected to have led to a rapid increase in groundwater extraction. This study aims to establish the effect of this development to the DGSL in this part of the lake. As a first step, we utilized towed electrical resistivity (ER) profiling to identify and map the potential and type of groundwater seepage off the southern coast of the lake. SRTM digital elevation models and synthetic aperture radar images were used to delineate lineaments which are potential fractures that cut across the study area. ER profiles indicate widespread occurrence of GDL across the shallower parts of the lake. In the more offshore, deeper parts of the lake, DGSL appears to be more limited possibly due to more muddy sediments there. However, in this area, narrow, vertical high resistivity columns cut through the lake floor suggesting more discrete GDLs possibly controlled by faults.

  19. Secondary forest succession and tree planting at the Laguna Cartagena and Cabo Rojo wildlife refuges in southwestern Puerto Rico.

    PubMed

    Weaver, Peter L; Schwagerl, Joseph J

    2008-12-01

    Secondary forest succession and tree planting are contributing to the recovery of the Cabo Rojo refuge (Headquarters and Salinas tracts) and Laguna Cartagena refuge (Lagoon and Tinaja tracts) of the Fish and Wildlife Service in southwestern Puerto Rico. About 80 species, mainly natives, have been planted on 44 ha during the past 25 y in an effort to reduce the threat of grass fires and to restore wildlife habitat. A 2007 survey of 9-y-old tree plantings on the Lagoon tract showed satisfactory growth rates for 16 native species. Multiple stems from individual trees at ground level were common. A sampling of secondary forest on the entire 109 ha Tinaja tract disclosed 141 native tree species, or 25% of Puerto Rico's native tree flora, along with 20 exotics. Five tree species made up about 58% of the total basal area, and seven species were island endemics. Between 1998 and 2003, tree numbers and basal area, as well as tree heights and diameter at breast height values (diameter at 1.4 m above the ground), increased on the lower 30 ha of the Tinaja tract. In this area, much of it subject to fires and grazing through 1996, exotic trees made up 25% of the species. Dry forest throughout the tropics is an endangered habitat, and its recovery (i.e., in biomass, structure, and species composition) at Tinaja may exceed 500 y. Future forests, however, will likely contain some exotics. PMID:19205183

  20. Snow extent measurements from geostationary satellites using an interactive computer system. [Salt and Verde River Basins, Arizona

    NASA Technical Reports Server (NTRS)

    Gird, R. S. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. A time series of GOES full resolution visible image sectors was viewed on the McIDAS video component in chronological order and registered to within plus or minus 1 image pixel to compute real time snow melting rates. Synoptic scale clouds were eliminated to create a snow covered area from a composite image. Results show good agreement with NESS products although a significant difference was noted for one two-day period when the NESS products showed an increase in the snow cover for the Verde Basin, while the GOES/McIDAS product implied no change in the snow cover for approximately the same period. A check of NWS radar reports indicated no precipitation had occurred within the Verde basin. The use of the registered image sequence eliminates instrument error since small changes in the snow cover between any two days are easily detected.

  1. The Admixture Structure and Genetic Variation of the Archipelago of Cape Verde and Its Implications for Admixture Mapping Studies

    PubMed Central

    Beleza, Sandra; Campos, Joana; Lopes, Jailson; Araújo, Isabel Inês; Hoppfer Almada, Ana; e Silva, António Correia; Parra, Esteban J.; Rocha, Jorge

    2012-01-01

    Recently admixed populations offer unique opportunities for studying human history and for elucidating the genetic basis of complex traits that differ in prevalence between human populations. Historical records, classical protein markers, and preliminary genetic data indicate that the Cape Verde islands in West Africa are highly admixed and primarily descended from European males and African females. However, little is known about the variation in admixture levels, admixture dynamics and genetic diversity across the islands, or about the potential of Cape Verde for admixture mapping studies. We have performed a detailed analysis of phenotypic and genetic variation in Cape Verde based on objective skin color measurements, socio-economic status (SES) evaluations and data for 50 autosomal, 34 X-chromosome, and 21 non-recombinant Y-chromosome (NRY) markers in 845 individuals from six islands of the archipelago. We find extensive genetic admixture between European and African ancestral populations (mean West African ancestry = 0.57, sd = 0.08), with individual African ancestry proportions varying considerably among the islands. African ancestry proportions calculated with X and Y-chromosome markers confirm that the pattern of admixture has been sex-biased. The high-resolution NRY-STRs reveal additional patterns of variation among the islands that are most consistent with differentiation after admixture. The differences in the autosomal admixture proportions are clearly evident in the skin color distribution across the islands (Pearson r = 0.54, P-value<2e–16). Despite this strong correlation, there are significant interactions between SES and skin color that are independent of the relationship between skin color and genetic ancestry. The observed distributions of admixture, genetic variation and skin color and the relationship of skin color with SES relate to historical and social events taking place during the settlement history of Cape Verde, and have

  2. Chronology of the 2014 volcanic eruption on the island of Fogo, Cape Verde

    NASA Astrophysics Data System (ADS)

    Silva, Sónia; Cardoso, Nadir; Alfama, Vera; Cabral, Jeremias; Semedo, Helio; Pérez, Nemesio M.; Dionis, Samara; Hernández, Pedro A.; Barrancos, José; Melián, Gladys V.; Pereira, José Manuel; Rodríguez, Fátima

    2015-04-01

    . Day, S. J., Heleno da Silva, S. I. N., and Fonseca, J. F. B. D.: A past giant lateral collapse and present-day flank instability of Fogo, Cape Verde Islands, J. Volcanol. Geotherm. Res., 94, 191-218, 1999. Foeken, J., Day, S., and Stuart, F.: Cosmogenic 3He exposure dating of the Quaternary basalts from Fogo, Cape Verdes: Implications for rift zone and magmatic reorganisation, Quaternary Geochron., 4, 37-49, doi:10.1016/j.quageo.2008.07.002, 2009. Ribeiro, O.: A ilha do Fogo e as suas erupções, 12a edição, Memórias, Série Geográfica, J. Inv. Ultramar, 1960. Torres, P.C., Madeira, J., Silva, L.C., Silveira, A.B., Serralheiro, A. & Mota Gomes, A. (1997) - Carta geológica das erupções históricas da ilha do Fogo: revisão e actualização, in "A erupção vulcânica de 1995 na ilha do Fogo, Cabo Verde", Lisboa, 119-132.

  3. Multi-disciplinary Monitoring of the 2014 Eruption of Fogo Volcano, Cape Verde

    NASA Astrophysics Data System (ADS)

    Fernandes, R. M. S.; Faria, B. V. E.

    2015-12-01

    The Fogo volcano, located in the Cape Verde Archipelago (offshore Western Africa), is a complete stratovolcano system. It is the most recent expression of the Cape Verde hotspot, that has formed the archipelago. The summit reaches ~2830m above sea level, and raises 1100m above Chã das Caldeiras, an almost flat circular area. The last eruption of Fogo started on November 23, 2014 (~10:00UTC), after 19 years of inactivity. C4G, a distributed research infrastructure created in 2014 in the framework of the Portuguese Roadmap for Strategic Research Infrastructures, collaborated immediately with INMG, the Cape Verdean Meteorological and Geophysical Institut with the goal of complementing the permanent geophysical monitoring network in operation on Fogo island. The INMG permanent network is composed of seven seismographic stations and three tiltmeter stations, with real-time data transmitted. On the basis of increased pre-event activity (which started in October 2014), INMG issued a formal alert of an impending eruption to the Civil Protection Agency, about 24 hours before the onset of the eruption. Although the eruption caused no casualties or personal injuries due to the warnings issued, the lava expelled by the eruption (which last until the end of January) destroyed the two main villages in the caldera (~1000 inhabitants) and covered vast areas of agricultural land, causing very large economic losses and an uncertain future of the local populations. The C4G team installed a network of seven GNSS receivers and nine seismometers, distributed by the entire island. The data collection started on 28th November 2014, and continued until the end of January 2015. The mission also included a new detailed gravimetric survey of the island, the acquisition of geological samples, and the analysis of the air quality during the eruption. We present here a detailed description of the monitoring efforts carried out during the eruption as well as initial results of the analysis of the

  4. Physical and chemical effects of grain aggregates on the Palos Verdes margin, southern California

    USGS Publications Warehouse

    Drake, D.E.; Eganhouse, R.; McArthur, W.

    2002-01-01

    Large discharges of wastewater and particulate matter from the outfalls of the Los Angeles County Sanitation Districts onto the Palos Verdes shelf since 1937 have produced an effluent-affected sediment deposit characterized by low bulk density, elevated organic matter content, and a high percentage of fine silt and clay particles relative to underlying native sands and sandy silts. Comparison of the results of grain-size analyses using a gentle wet-sieving technique that preserves certain grain aggregates to the results of standard size analyses of disaggregated particles shows that high percentages (up to 50%) of the silt and clay fractions of the effluent-affected mud are incorporated in aggregates having intermediate diameters in the fine-to-medium sand size range (63-500 ??m), Scanning electron microscope images of the aggregates show that they are predominantly oval fecal pellets or irregularly shaped fragments of pellets. Deposit-feeding polychaete worms such as Capitella sp. and Mediomastus sp., abundant in the mud-rich effluent-affected sediment on Palos Verdes shelf, are probably responsible for most of the grain aggregates through fecal pellet production. Particle settling rates and densities, and the concentrations of organic carbon and p,p???-DDE, a metabolite of the hydrophobic pesticide DDT, were determined for seven grain-size fractions in the effluent-affected sediment. Fecal pellet grain densities ranged from about 1.2 to 1.5 g/cc, and their average settling rates were reduced to the equivalent of about one phi size relative to spherical quartz grains of the same diameter. However, repackaging of fine silt and clay grains into the sand-sized fecal pellets causes an effective settling rate increase of up to 3 orders of magnitude for the smallest particles incorporated in the pellets. Moreover, organic carbon and p,p???-DDE exhibit a bimodal distribution with relatively high concentrations in the finest size fraction (0-20 ??m), as expected, and a

  5. Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides.

    PubMed

    Rocha, Hélio Daniel Ribeiro; Paiva, Marcelo Henrique Santos; Silva, Norma Machado; de Araújo, Ana Paula; Camacho, Denise dos Reis da Rosa de Azevedo; Moura, Aires Januário Fernandes da; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira; Santos, Maria Alice Varjal de Melo

    2015-12-01

    In 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortality<80%) and temephos (RR90=4.4) but susceptibility to malathion (mortality≥98%), Bti and diflubenzuron. The low level of resistance to temephos did not affect the effectiveness of Abate(®). The enzymatic analysis conducted in 2012 revealed slight changes in the activities of GST (25%), MFO (18%), α-esterase (19%) and β-esterase (17%), but no significant changes in 2014. Target site resistance mutations were not detected. Our results suggest that the A. aegypti population from Santiago is resistant to two major

  6. A complete hydro-climate model chain to investigate the influence of sea surface temperature on recent hydroclimatic variability in subtropical South America (Laguna Mar Chiquita, Argentina)

    NASA Astrophysics Data System (ADS)

    Troin, Magali; Vrac, Mathieu; Khodri, Myriam; Caya, Daniel; Vallet-Coulomb, Christine; Piovano, Eduardo; Sylvestre, Florence

    2016-03-01

    During the 1970s, Laguna Mar Chiquita (Argentina) experienced a dramatic hydroclimatic anomaly, with a substantial rise in its level. Precipitations are the dominant driving factor in lake level fluctuations. The present study investigates the potential role of remote forcing through global sea surface temperature (SST) fields in modulating recent hydroclimatic variability in Southeastern South America and especially over the Laguna Mar Chiquita region. Daily precipitation and temperature are extracted from a multi-member LMDz atmospheric general circulation model (AGCM) ensemble of simulations forced by HadISST1 observed time-varying global SST and sea-ice boundary conditions from 1950 to 2005. The various members of the ensemble are only different in their atmospheric initial conditions. Statistical downscaling (SD) is used to adjust precipitation and temperature from LMDz ensemble mean at the station scale over the basin. A coupled basin-lake hydrological model ( cpHM) is then using the LMDz-downscaled (LMDz-SD) climate variables as input to simulate the lake behavior. The results indicate that the long-term lake level trend is fairly well depicted by the LMDz-SD- cpHM simulations. The 1970s level rise and high-level conditions are generally well captured in timing and in magnitude when SST-forced AGCM-SD variables are used to drive the cpHM. As the LMDz simulations are forced solely with the observed sea surface conditions, the global SST seems to have an influence on the lake level variations of Laguna Mar Chiquita. As well, this study shows that the AGCM-SD- cpHM model chain is a useful approach for evaluating long-term lake level fluctuations in response to the projected climate changes.

  7. Uranium and lanthanides in surficial sediments of Laguna Ojo de Liebre and evaporation ponds of Exportadora de Sal, Guerrero Negro, México.

    NASA Astrophysics Data System (ADS)

    Grajeda-Muñoz, M. M.; Choumiline, E.; Zaposhnikov, D.

    2007-05-01

    To assess uranium and lanthanides behavior in hypersaline environments, surficial sediment samples were taken from Laguna Ojo de Liebre as well as from the evaporation ponds of Exportadora de Sal (the largest natural salt producing facility in the continent). A total of 63 surficial sediment samples from the laguna and 30 samples from the ponds were analyzed by inductive coupled plasma-mass spectrometry for uranium (sediments, deposits and solution) and instrumental neutron activation analysis for REEs in sediments and deposits. Results show that the behavior is all but similar between light and heavy REEs with the exception of Eu which shows a very different pattern of surficial distribution in Laguna Ojo de Liebre with a maximum concentrations in the sediments near the head of the lagoon. Data normalized with North American Shale Composite (NASC) show 3 distinct signature patterns on the surficial sediments, all of them enriched regarding the values of NASC. As for U total content in sediments and solid deposits it shows a higher concentration towards the head of the lagoon (3 mg/kg), from where the water is pumped to the sequence of evaporation ponds, with the lowest values being close to 1 mg/kg near the mouth of the lagoon. The interesting phenomenon begins in the evaporation ponds, where uranium is almost constant in sediments and deposits (0.15-1.5 mg/kg) but behaves conservately in the brine solution, increasing proportionally with salt content (U, 5-20 mg/kg; salt content, 40-250 g/kg). Non lithogenic U was calculated with Sc as reference. Most of the measured U was non lithogenic in the sediments of the lagoon and ponds. The distribution coefficient k= U(non-lith)/U(dis) shows a maximum value at ponds I and II (salt content 40-80 g/kg) decreasing with increasing salinity.

  8. CV-Dust: Atmospheric aerosol in the Cape Verde region: carbon and soluble fractions of PM10

    NASA Astrophysics Data System (ADS)

    Pio, C.; Nunes, T.; Cardoso, J.; Caseiro, A.; Custódio, D.; Cerqueira, M.; Patoilo, D.; Almeida, S. M.; Freitas, M. C.

    2012-04-01

    Every year, billions of tons of eroded mineral soils from the Saharan Desert and the Sahel region, the largest dust source in the world, cross Mediterranean towards Europe, western Asia and the tropical North Atlantic Ocean as far as the Caribbean and South America. Many aspects of the direct and indirect effects of dust on climate are not well understood and the bulk and surface chemistry of the mineral dust particles determines interactions with gaseous and other particle species. The quantification of the magnitude of warming or cooling remains open because of the strong variability of the atmospheric dust burden and the lack of representative data for the spatial and temporal distribution of the dust composition. CV-Dust is a project that aims at provide a detailed data on the size distribution and the size-resolved chemical and mineralogical composition of dust emitted from North Africa using a natural laboratory like Cape Verde. This archipelago is located in an area of massive dust transport from land to ocean, and is thus ideal to set up sampling devices that are able to characterize and quantify dust transported from Africa. Moreover, Cape Verde's future economic prospects depend heavily on the encouragement of tourism, therefore it is essential to elucidate the role of Saharan dust may play in the degradation of Cape Verde air quality. The main objectives of CV-Dust project are: 1) to characterize the chemical and mineralogical composition of dust transported from Africa by setting up an orchestra of aerosol sampling devices in the strategic archipelago of Cape Verde; 2) to identify the sources of particles in Cape Verde by using receptor models; 3) to elucidate the role Saharan dust may play in the degradation of Cape Verde air quality; 4) to model processes governing dust production, transport, interaction with the radiation field and removal from the atmosphere. Here we present part of the data obtained throughout the last year, involving a set of more

  9. 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

  10. PASADO - ICDP Deep Drilling at Laguna Potrok Aike (Argentina): A 50 ka Record of Increasing Environmental Dynamics

    NASA Astrophysics Data System (ADS)

    Zolitschka, Bernd; Anselmetti, Flavio; Ariztegui, Daniel; Francus, Pierre; Gebhardt, Catalina; Kliem, Annette Hahn Pierre; Lücke, Andreas; Ohlendorf, Christian; Schäbitz, Frank; Wastegard, Stefan

    2010-05-01

    Laguna Potrok Aike, located in the South-Patagonian province of Santa Cruz (52°58'S, 70°23'W), was formed by a volcanic (maar) eruption in the late Quaternary Pali Aike Volcanic Field several hundred thousand years ago. This archive holds a unique record of paleoclimatic and paleoecological variability from a region sensitive to variations in southern hemispheric wind and pressure systems, which provide a significant cornerstone for the understanding of the entire global climate system. Moreover, Laguna Potrok Aike is close to many active volcanoes allowing a better understanding of the history of volcanism in the Pali Aike Volcanic Field as well as in the Andean mountain chain, the latter located in a distance of less than 150 km to the west. Finally, Patagonia is the source region of eolian dust blown from the South American continent into the South Atlantic and onto the Antarctic ice sheet. The currently ongoing global climate change, the thread of volcanic hazards as well as of regional dust storms are of increasing socio-economic relevance and thus challenging scientific themes that are tackled for southernmost South America with an interdisciplinary research approach in the framework of the ICDP-funded "Potrok Aike Maar Lake Sediment Archive Drilling Project" (PASADO). Using the GLAD800 drilling platform seven holes were drilled in the southern spring of 2008. A total of 510 m of lacustrine sediments were recovered by an international scientific team from the central 100 m deep basin with an excellent core recovery rate of 94.4%. The reference profile with a composite depth of 106 m consists of undisturbed laminated and sand-layered lacustrine silts with an increasing number of coarse gravel layers, turbidites and homogenites with depth. Below 80 m composite depth two mass-movement deposits (10 m and 5 m in thickness) are recorded. These deposits show tilted and distorted layers as well as nodules of fine-grained sediments and randomly distributed gravel

  11. Method to identify wells that yield water that will be replaced by water from the Colorado River downstream from Laguna Dam in Arizona and California

    USGS Publications Warehouse

    Owen-Joyce, Sandra J.; Wilson, Richard P.; Carpenter, Michael C.; Fink, James B.

    2000-01-01

    Accounting for the use of Colorado River water is required by the U.S. Supreme Court decree, 1964, Arizona v. California. Water pumped from wells on the flood plain and from certain wells on alluvial slopes outside the flood plain is presumed to be river water and is accounted for as Colorado River water. The accounting-surface method developed for the area upstream from Laguna Dam was modified for use downstream from Laguna Dam to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. Use of the same method provides a uniform criterion of identification for all users pumping water from wells by determining if the static water-level elevation in the well is above or below the elevation of the accounting surface. Wells that have a static water-level elevation equal to or below the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation above the accounting surface are presumed to yield river water stored above river level. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The river aquifer consists of permeable sediments and sedimentary rocks that are hydraulically connected to the Colorado River so that water can move between the river and the aquifer in response to withdrawal of water from the aquifer or differences in water-level elevations between the river and the aquifer. The subsurface limit of the river aquifer is the nearly impermeable bedrock of the bottom and sides of the basins that underlie the Yuma area and adjacent valleys. The accounting surface represents the elevation and slope of the unconfined static water table in the river aquifer outside the flood plain of the Colorado River that would exist if the river were the only source of water to the river aquifer. The accounting surface was generated by using water

  12. Linking Modern, Rapid, Surface Uplift at the Laguna del Maule Volcanic Field, Chilean Andes, to Rhyolitic Magma-Driven Uplift Spanning the Holocene

    NASA Astrophysics Data System (ADS)

    Singer, B. S.; Tikoff, B.; Le Mével, H.; Andersen, N. L.; Cordova, L.; Licciardi, J. M.

    2015-12-01

    The Laguna del Maule Volcanic Field includes an unusually large and recent concentration of silicic eruptions across a 23x17 km lake basin atop the southern Andes. We present findings that allow us to link currently observed deformation with a geological record of surface change spanning the Holocene. Since 2007 the crust here has been inflating at more than 20 cm/y. Geological, petrological, and geophysical findings have led to the hypothesis that the silicic vents have tapped an extensive, but ephemeral, layer of crystal-poor rhyolitic melt that began to form atop a mush zone that was established by ~20 ka, with a renewed phase of rhyolite eruptions concentrated around the southern flank of the basin during the Holocene (Singer et al., 2014). One of the earliest rhyolites, the 1 km3 Espejos coulée, 40Ar/39Ar-dated at 19 ka, dammed the northern outlet of Laguna del Maule raising the lake level ~200 m to form a prominent basin-wide shoreline. This shoreline was abandoned during an outbreak flood in the earliest Holocene. Surface exposure and 14C dating underway aims to refine the timing of the drop in lake level. Using an initial series of 40 short static GPS measurements around the basin, referenced to a set of 5 continuous GPS receivers, the elevation of this paleo-shoreline was determined to be 67 m higher at the southern end of the lake compared to the north. Interpretations of current surface deformation (Le Mével et al., in press), magnetotelluric data, earthquake distribution, and gravity changes suggest that magma is currently intruding at about 0.03 km3/yr at ~5 km depth. The amount of magma required to raise the surface 2 m during 8 yr is ~0.25 km3. If similar episodes of intrusion raised the roof of the magma reservoir by >60 m during the Holocene, it implies: (1) rapid accumulation of ~6 km3 of magma within the shallow crust, and (2) the locus of magma intrusion has shifted northward several km during the last 10 ky. It remains unclear whether any of

  13. Intra-community infanticide and forced copulation in spider monkeys: a multi-site comparison between Cocha Cashu, Peru and Punta Laguna, Mexico.

    PubMed

    Gibson, K Nicole; Vick, Laura G; Palma, Ana Cristina; Carrasco, Farah M; Taub, David; Ramos-Fernández, Gabriel

    2008-05-01

    We describe two cases of infanticide, two suspected infanticides, and a forced copulation by familiar resident males in two populations of wild spider monkeys (Ateles belzebuth chamek and A. geoffroyi yucatanensis). These are the first known infanticides and forced copulation in spider monkeys. Data were gathered from four neighboring communities of spider monkeys in Manu National Park at the Cocha Cashu Biological Station, Peru and two communities in the Otoch Ma'ax Yetel Kooh Reserve at Punta Laguna, Mexico, during intensive field studies of over 2,000 hr each. These are rare behaviors, but results suggest that mating history and sexual coercion are important in spider monkey social relationships. PMID:18064591

  14. Microbial Diversity in Sediment Ecosystems (Evaporites Domes, Microbial Mats, and Crusts) of Hypersaline Laguna Tebenquiche, Salar de Atacama, Chile.

    PubMed

    Fernandez, Ana B; Rasuk, Maria C; Visscher, Pieter T; Contreras, Manuel; Novoa, Fernando; Poire, Daniel G; Patterson, Molly M; Ventosa, Antonio; Farias, Maria E

    2016-01-01

    We combined nucleic acid-based molecular methods, biogeochemical measurements, and physicochemical characteristics to investigate microbial sedimentary ecosystems of Laguna Tebenquiche, Atacama Desert, Chile. Molecular diversity, and biogeochemistry of hypersaline microbial mats, rhizome-associated concretions, and an endoevaporite were compared with: The V4 hypervariable region of the 16S rRNA gene was amplified by pyrosequencing to analyze the total microbial diversity (i.e., bacteria and archaea) in bulk samples, and in addition, in detail on a millimeter scale in one microbial mat and in one evaporite. Archaea were more abundant than bacteria. Euryarchaeota was one of the most abundant phyla in all samples, and particularly dominant (97% of total diversity) in the most lithified ecosystem, the evaporite. Most of the euryarchaeal OTUs could be assigned to the class Halobacteria or anaerobic and methanogenic archaea. Planctomycetes potentially also play a key role in mats and rhizome-associated concretions, notably the aerobic organoheterotroph members of the class Phycisphaerae. In addition to cyanobacteria, members of Chromatiales and possibly the candidate family Chlorotrichaceae contributed to photosynthetic carbon fixation. Other abundant uncultured taxa such as the candidate division MSBL1, the uncultured MBGB, and the phylum Acetothermia potentially play an important metabolic role in these ecosystems. Lithifying microbial mats contained calcium carbonate precipitates, whereas endoevoporites consisted of gypsum, and halite. Biogeochemical measurements revealed that based on depth profiles of O2 and sulfide, metabolic activities were much higher in the non-lithifying mat (peaking in the least lithified systems) than in lithifying mats with the lowest activity in endoevaporites. This trend in decreasing microbial activity reflects the increase in salinity, which may play an important role in the biodiversity. PMID:27597845

  15. Microbial Diversity in Sediment Ecosystems (Evaporites Domes, Microbial Mats, and Crusts) of Hypersaline Laguna Tebenquiche, Salar de Atacama, Chile

    PubMed Central

    Fernandez, Ana B.; Rasuk, Maria C.; Visscher, Pieter T.; Contreras, Manuel; Novoa, Fernando; Poire, Daniel G.; Patterson, Molly M.; Ventosa, Antonio; Farias, Maria E.

    2016-01-01

    We combined nucleic acid-based molecular methods, biogeochemical measurements, and physicochemical characteristics to investigate microbial sedimentary ecosystems of Laguna Tebenquiche, Atacama Desert, Chile. Molecular diversity, and biogeochemistry of hypersaline microbial mats, rhizome-associated concretions, and an endoevaporite were compared with: The V4 hypervariable region of the 16S rRNA gene was amplified by pyrosequencing to analyze the total microbial diversity (i.e., bacteria and archaea) in bulk samples, and in addition, in detail on a millimeter scale in one microbial mat and in one evaporite. Archaea were more abundant than bacteria. Euryarchaeota was one of the most abundant phyla in all samples, and particularly dominant (97% of total diversity) in the most lithified ecosystem, the evaporite. Most of the euryarchaeal OTUs could be assigned to the class Halobacteria or anaerobic and methanogenic archaea. Planctomycetes potentially also play a key role in mats and rhizome-associated concretions, notably the aerobic organoheterotroph members of the class Phycisphaerae. In addition to cyanobacteria, members of Chromatiales and possibly the candidate family Chlorotrichaceae contributed to photosynthetic carbon fixation. Other abundant uncultured taxa such as the candidate division MSBL1, the uncultured MBGB, and the phylum Acetothermia potentially play an important metabolic role in these ecosystems. Lithifying microbial mats contained calcium carbonate precipitates, whereas endoevoporites consisted of gypsum, and halite. Biogeochemical measurements revealed that based on depth profiles of O2 and sulfide, metabolic activities were much higher in the non-lithifying mat (peaking in the least lithified systems) than in lithifying mats with the lowest activity in endoevaporites. This trend in decreasing microbial activity reflects the increase in salinity, which may play an important role in the biodiversity. PMID:27597845

  16. Holocene History of the Chocó Rain Forest from Laguna Piusbi, Southern Pacific Lowlands of Colombia

    NASA Astrophysics Data System (ADS)

    Behling, Hermann; Hooghiemstra, Henry; Negret, Alvaro José

    1998-11-01

    A high-resolution pollen record from a 5-m-long sediment core from the closed-lake basin Laguna Piusbi in the southern Colombian Pacific lowlands of Chocó, dated by 11 AMS 14C dates that range from ca. 7670 to 220 14C yr B.P., represents the first Holocene record from the Chocó rain forest area. The interval between 7600 and 6100 14C yr B.P. (500-265 cm), composed of sandy clays that accumulated during the initial phase of lake formation, is almost barren of pollen. Fungal spores and the presence of herbs and disturbance taxa suggest the basin was at least temporarily inundated and the vegetation was open. The closed lake basin might have formed during an earthquake, probably about 4400 14C yr B.P. From the interval of about 6000 14C yr B.P. onwards, 200 different pollen and spore types were identified in the core, illustrating a diverse floristic composition of the local rain forest. Main taxa are Moraceae/Urticaceae, Cecropia,Melastomataceae/Combretaceae, Acalypha, Alchornea,Fabaceae, Mimosa, Piper, Protium, Sloanea, Euterpe/Geonoma, Socratea,and Wettinia.Little change took place during that time interval. Compared to the pollen records from the rain forests of the Colombian Amazon basin and adjacent savannas, the Chocó rain forest ecosystem has been very stable during the late Holocene. Paleoindians probably lived there at least since 3460 14C yr B.P. Evidence of agricultural activity, shown by cultivation of Zea maissurrounding the lake, spans the last 1710 yr. Past and present very moist climate and little human influence are important factors in maintaining the stable ecosystem and high biodiversity of the Chocó rain forest.

  17. Evaluating HIV prevention strategies for populations in key affected groups: The example of Cabo Verde

    PubMed Central

    Monteiro, João Filipe G.; Galea, Sandro; Flanigan, Timothy; Monteiro, Maria de Lourdes; Friedman, Samuel R.; Marshall, Brandon DL

    2015-01-01

    Objectives We used an individual-based model to evaluate the effects of hypothetical prevention interventions on HIV incidence trajectories in a concentrated, mixed epidemic setting from 2011 to 2021, and using Cabo Verde as an example. Methods Simulations were conducted to evaluate the extent to which early HIV treatment and optimization of care, HIV testing, condom distribution, and substance abuse treatment could eliminate new infections (i.e., reduce incidence to less than 10 cases per 10,000 person-years) among non-drug users, female sex workers (FSW), and people who use drugs (PWUD). Results Scaling up all four interventions resulted in the largest decreases in HIV, with estimates ranging from 1.4 (95%CI:1.36–1.44) per 10,000 person-years among non-drug users to 8.2 (95%CI:7.8–8.6) per 10,000 person-years among PWUD in 2021. Intervention scenarios targeting FWS and PWUD also resulted in HIV incidence estimates at or below 10 per 10,000 person-years by 2021 for all population sub-groups. Conclusions Our results suggest that scaling up multiple interventions among entire population is necessary to achieve elimination. However, prioritizing key populations with this combination prevention strategy may also result in a substantial decrease in total incidence. PMID:25838121

  18. Hydrogeological investigation in Santiago Island (Cabo Verde) using magnetotellurics and VLF methods

    NASA Astrophysics Data System (ADS)

    Monteiro Santos, Fernando A.; Almeida, Eugénio P.; Gomes, Mota; Pina, António

    2006-08-01

    A geoelectromagnetic research was carried out in the Santa Cruz region (Santiago Island, Cabo Verde) during June 2004. The survey comprised MT soundings and VLF profiles. The main purpose of the MT profile, carried out across three important valleys associated with freshwater aquifers, was to study the tectonic structures correlated to seawater infiltration. The VLF method was used inside of the valleys for investigating shallow structures related to the aquifer contamination by seawater. Numerical modelling shows that the ocean effect is not important for MT data collected at periods shorter than 1 s. The MT data were inverted using a two-dimensional approach, to obtain the sub-superficial electrical conductivity distribution. The VLF data were processed applying the Karous-Hjelt filters to obtain the equivalent current distribution and inverted using 2-D approach. The results obtained in one of the most important valleys show anomalous current concentration/low resistivity (<20 Ω m) areas at depths greater than 40 m that may correspond to an increase in seawater content. The MT data modelling show that the deep zones beneath the valley are strongly fractured representing good pathways for seawater circulation. The depth of the conductive zones increases from south to north, suggesting a northward decreasing of the seawater infiltration effect. This observation correlates very well with in situ geochemical observations.

  19. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands

    USGS Publications Warehouse

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D.N.

    2010-01-01

    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6 Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350 m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100 m of surface rise.

  20. Bromocarbons in the tropical marine boundary layer at the Cape Verde Observatory - measurements and modelling

    NASA Astrophysics Data System (ADS)

    O'Brien, L. M.; Harris, N. R. P.; Robinson, A. D.; Gostlow, B.; Warwick, N.; Yang, X.; Pyle, J. A.

    2009-02-01

    A new gas chromatograph was used to make measurements of halocarbons at the Cape Verde observatory during late May and early June 2007. The instrument demonstrated its potential for long-term autonomous measurements. Bromoform (CHBr3) exhibits the most variability of all the halocarbons observed, ranging from a background concentration of about 4 ppt to a maximum of >40 ppt during the course of the measurement period. Dibromomethane (CH2Br2) correlates well with CHBr3, suggesting a common regional source. Methyl iodide (CH3I) does not correlate with these bromocarbons, with base levels of around 1-2 ppt and some periods of much higher mixing ratios. Model studies with published bromocarbon emission rates do not reproduce the observations. Local emission magnitudes and CHBr3:CH2Br2 ratios must be increased more in line with the recent observations of Yokouchi et al. (2005) to improve the model to measurement comparison. Even when the model reproduces the observed bromocarbons, modelled BrO is much less than recent tropical observations (Read et al., 2008). A sea salt source seems the likely explanation. When high BrO is reproduced, the model agrees much better with the observed ozone changes, including diurnal variation, during the measurement period but it is suggested that a representation of iodine chemistry in the model is also required.

  1. Bromocarbons in the tropical marine boundary layer at the Cape Verde Observatory - measurements and modelling

    NASA Astrophysics Data System (ADS)

    O'Brien, L. M.; Harris, N. R. P.; Robinson, A. D.; Gostlow, B.; Warwick, N.; Yang, X.; Pyle, J. A.

    2009-11-01

    A new gas chromatograph was used to make measurements of halocarbons at the Cape Verde observatory during late May and early June 2007. The instrument demonstrated its potential for long-term autonomous measurements. Bromoform (CHBr3) exhibits the most variability of all the halocarbons observed, ranging from a background concentration of about 4 ppt to a maximum of >40 ppt during the course of the measurement period. CH2Br2 correlates well with bromoform, suggesting a common regional source. Methyl iodide does not correlate with these bromocarbons, with base levels of around 1-2 ppt and some periods of much higher mixing ratios. Using published bromocarbon emission rates, our chemical transport model studies, presented here, do not reproduce the observations. Local emission magnitudes and CHBr3:CH2Br2 ratios must be increased more in line with the recent observations of Yokouchi et al. (2005) to improve the model to measurement comparison. Even when the model reproduces the observed bromocarbons, modelled BrO is much less than recent tropical observations (Read et al., 2008). A sea salt source seems the likely explanation. When high BrO is reproduced, the model agrees much better with the observed ozone changes, including diurnal variation, during the measurement period but it is suggested that a representation of iodine chemistry in the model is also required.

  2. In situ measurements of chlorinated hydrocarbons in the water column off the Palos Verdes Peninsula, California

    SciTech Connect

    Zeng, E.Y.; Yu, C.C.; Tran, K.

    1999-02-01

    Spatial distributions of DDT and its primary metabolites (DDTs) and polychlorinated biphenyls (PCBs) in the water column off the Palos Verdes Peninsula, CA, were measured in the winter and summer of 1997 using an in situ sampling method. The concentrations of DDTs ranged from 0.6 to 15.8 ng/L, while those of PCBs ranged from 0.06 to 15.8 ng/L, while those of PCBs ranged from 0.06 to 1.14 ng/L at eight sampling stations. The spatial distribution patterns of DDTs and PCBs as well as the DDT/PCB concentration ratio in the water column were similar to those found in the sediment, and the vertical profiles of DDTs and PCBs at both sampling seasons exponentially decreased with increasing distance from the sea floor. In addition, the partitioning characteristics of DDTs and selected PCB congeners indicated a tendency of mobilization from sediment to water. All of these findings strongly suggest that contaminated sediments are a main source of DDT and PCB inputs to the water column surrounding the study site.

  3. Ocean variability around Cape Verde Archipelago from near real time satellite altimetry and SST images

    NASA Astrophysics Data System (ADS)

    Lázaro, C.; Fernandes, M. J.

    2003-04-01

    In this work, the synergy of data acquired by the radar altimeter (RA) and the infrared radiometer (ATSR-2/IRR) aboard the ERS-2 satellite, presently available in near real time, is exploited. The aim is to extract valid oceanographic information for the characterisation of ocean circulation around the Cape Verde Archipelago (North Atlantic Ocean) and its seasonal variability. For the data acquisition period (June 2001 to May 2002, ERS-2 cycles 64 to 73), synoptic maps representing sea surface temperature (SST) and absolute dynamic topography (ADT) values for each cycle were created. The methodology adopted for the near real time data processing is described. As the accuracy of the orbit and geophysical corrections is a fundamental issue in the evaluation of altimetric data, the near real time products were compared with the OPR products, which have several months of latency. Based upon the ADT values, intensity and direction of surface geostrophic currents were calculated. The SST variability was investigated and compared with the absolute dynamic topography variability. The seasonal cycle of the oceanographic characteristics, as extracted from the combined analysis of the two variables, is perfectly visible along the year of study.

  4. REE and other trace and major elements in the topsoil layer of Santiago island, Cape Verde

    NASA Astrophysics Data System (ADS)

    Marques, Rosa; Prudêncio, M. Isabel; Rocha, Fernando; Cabral Pinto, Marina M. S.; Silva, M. Manuela V. G.; Ferreira da Silva, Eduardo

    2012-02-01

    Geochemistry of major, trace and rare earth elements (REEs) of soils of Santiago island (Cape Verde) has been done in order to characterize soils developed on volcanic rocks and Quaternary sediments, contributing to the establishment of a geochemical atlas of the island. Sampling was made according to the recommendations of the IGCP 259 ("International Geochemical Mapping"). REE clearly differentiate soils with contrasting parent materials, particularly carbonatites-related soils, where lower MREE/LREE and MREE/HREE ratios were found, associated with higher contents of Ba, Th and U. Total contents of Cs, As and Ga are associated with the finer soils. The percentage of Fe, Co, Mn and Sc extracted using aqua regia increased with increase of the clay size proportion. Concerning potentially pollutant elements, As contents increase with decreasing particle size, and very high concentrations of Cr were found in some soils. However, As is less available in the finer soils and the percentages of extraction of Cr are low, limiting eventual environmental and health effects in the Santiago island.

  5. New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

    PubMed Central

    Dillehay, Tom D.; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M.; Pino, Mario; Collins, Michael B.; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S.; Hartmann, Gelvam A.; Mella, Mauricio; González, Andrea; Dix, George

    2015-01-01

    Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia. PMID:26580202

  6. Fine scale structure of an Anticyclonic eddy off Cape Verde peninsula observed from Glider

    NASA Astrophysics Data System (ADS)

    Kolodziejczyk, Nicolas; Testor, Pierre; Lazar, Alban; Echevin, Vincent; Krahmann, Gerd; Faye, Saliou; Wade, Malik; Estrade, Philippe; Capet, Xavier; Brehmer, Patrice

    2015-04-01

    Measurements from a joint French and German Glider transect along 14.7°N between Dakar/Senegal and the Cape Verde archipelago during March-April 2014 are used to investigate the transversal structure of an anticyclonic eddy. The anticyclone is centered around 14.7°N-21.6°W with a maximum surface azimuthal velocity of about 0.25 m s-1 and is located in a frontal region separating warm off-shore cooler near-shore surface waters. At depth (below 100 m) the anticyclone presents lower temperature and salinity than the surrounding water masses, but an oxygenated core. The surface relative vorticity derived from AVISO altimetry suggests that the anticyclone was formed about around 12°N just off the continental shelf. At depth the anticyclonic core is associated with fine-scale vertical and horizontal structures. These features exhibits vertical density-compensated property gradient at scales between 5-100 m. The spectra of isopycnal salinity and oxygen variance roll off as k-3/5-k-2 in the horizontal wavenumber range 10-100 km (with substantial uncertainties on the exact spectral slope). Overall, the submesoscale features accompanying the eddy are compatible with tracer stirring. Speculations on the impact of such anticyclonic eddies on the ventilation of the North Atlantic Oxygen Minimum Zone are proposed.

  7. New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile.

    PubMed

    Dillehay, Tom D; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M; Pino, Mario; Collins, Michael B; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S; Hartmann, Gelvam A; Mella, Mauricio; González, Andrea; Dix, George

    2015-01-01

    Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia. PMID:26580202

  8. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands

    NASA Astrophysics Data System (ADS)

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D. N.

    2010-11-01

    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100m of surface rise.

  9. Human effects on the hydrologic system of the Verde Valley, central Arizona, 1910–2005 and 2005–2110, using a regional groundwater flow model

    USGS Publications Warehouse

    Garner, Bradley D.; Pool, D.R.; Tillman, Fred D; Forbes, Brandon T.

    2013-01-01

    Water budgets were developed for the Verde Valley of central Arizona in order to evaluate the degree to which human stresses have affected the hydrologic system and might affect it in the future. The Verde Valley is a portion of central Arizona wherein concerns have been raised about water availability, particularly perennial base flow of the Verde River. The Northern Arizona Regional Groundwater Flow Model (NARGFM) was used to generate the water budgets and was run in several configurations for the 1910–2005 and 2005–2110 time periods. The resultant water budgets were subtracted from one another in order to quantify the relative changes that were attributable solely to human stresses; human stresses included groundwater withdrawals and incidental and artificial recharge but did not include, for example, human effects on the global climate. Three hypothetical and varied conditions of human stresses were developed and applied to the model for the 2005–2110 period. On the basis of this analysis, human stresses during 1910–2005 were found to have already affected the hydrologic system of the Verde Valley, and human stresses will continue to affect the hydrologic system during 2005–2110. Riparian evapotranspiration decreased and underflow into the Verde Valley increased because of human stresses, and net groundwater discharge to the Verde River in the Verde Valley decreased for the 1910–2005 model runs. The model also showed that base flow at the upstream end of the study area, as of 2005, was about 4,900 acre-feet per year less than it would have been in the absence of human stresses. At the downstream end of the Verde Valley, base flow had been reduced by about 10,000 acre-feet per year by the year 2005 because of human stresses. For the 2005–2110 period, the model showed that base flow at the downstream end of the Verde Valley may decrease by an additional 5,400 to 8,600 acre-feet per year because of past, ongoing, and hypothetical future human

  10. Y-chromosome lineages in Cabo Verde Islands witness the diverse geographic origin of its first male settlers.

    PubMed

    Gonçalves, Rita; Rosa, Alexandra; Freitas, Ana; Fernandes, Ana; Kivisild, Toomas; Villems, Richard; Brehm, António

    2003-11-01

    The Y-chromosome haplogroup composition of the population of the Cabo Verde Archipelago was profiled by using 32 single-nucleotide polymorphism markers and compared with potential source populations from Iberia, west Africa, and the Middle East. According to the traditional view, the major proportion of the founding population of Cabo Verde was of west African ancestry with the addition of a minor fraction of male colonizers from Europe. Unexpectedly, more than half of the paternal lineages (53.5%) of Cabo Verdeans clustered in haplogroups I, J, K, and R1, which are characteristic of populations of Europe and the Middle East, while being absent in the probable west African source population of Guiné-Bissau. Moreover, a high frequency of J* lineages in Cabo Verdeans relates them more closely to populations of the Middle East and probably provides the first genetic evidence of the legacy of the Jews. In addition, the considerable proportion (20.5%) of E3b(xM81) lineages indicates a possible gene flow from the Middle East or northeast Africa, which, at least partly, could be ascribed to the Sephardic Jews. In contrast to the predominance of west African mitochondrial DNA haplotypes in their maternal gene pool, the major west African Y-chromosome lineage E3a was observed only at a frequency of 15.9%. Overall, these results indicate that gene flow from multiple sources and various sex-specific patterns have been important in the formation of the genomic diversity in the Cabo Verde islands. PMID:12942365

  11. A volcanological and geochemical investigation of Boa Vista, Cape Verde Islands; 40Ar/ 39Ar geochronology and field constraints

    NASA Astrophysics Data System (ADS)

    Dyhr, Charlotte T.; Holm, Paul M.

    2010-01-01

    Boa Vista, the easternmost island in the Cape Verde archipelago, consists of volcanic products, minor intrusions and a thin partial sedimentary cover. The first 15 age results from 40Ar/ 39Ar incremental heating analysis of groundmass separates from volcanic and plutonic rocks from Boa Vista are presented. The combination of age results and field observations demonstrates that the volcanic activity that formed the island occurred in three main stages: (1) > 16 Ma, (2) 15-12.5 Ma and (3) 9.5-4.5 Ma. The first stage, restricted to the north eastern part of the island, is dominated by ankaramitic lavas. The second stage, consisting of evolved lavas of phonolitic-trachytic compositions and nepheline syenites, makes up large central parts of the island. The large volume of evolved rocks and the extended eruption period of several Ma make stage 2 in Boa Vista unique to Cape Verde. Mainly basanites and nephelinites were erupted during the third stage, initially dominated by eruption of subaerial mafic lavas around 9 Ma. Pillow lavas are erupted around 7 Ma whereupon dominantly subaerial mafic lavas were erupted. Stage 3 saw volcanism in many centres distributed mainly along the present coastline and with activity partly overlapping in time. The volcanic evolution of Boa Vista constrains the initiation of volcanic activity in the Cape Verde archipelago to the eastern islands. Major and trace element geochemistry of 160 volcanic and plutonic rocks representing the entire exposed chronological sequence on Boa Vista is presented, revealing an extremely well developed Daly Gap. Only a little was modified from the mafic magmas that rose in small batches from the mantle. Compositional variation distinguishes each volcanic complex and was to a large extent present in the mantle melts. The highly evolved stage 2 phonolites and trachytes are related through the fractional crystallization of three compositionally distinct magmas. Two of these may have been derived by crystal

  12. Soil and water conservation strategies and impact on sustainable livelihood in Cape Verde - Case study of Ribeira Seca watershed

    NASA Astrophysics Data System (ADS)

    Baptista, I.; Ferreira, A. D.; Tavares, J.; Querido, A. L. E.; Reis, A. E. A.; Geissen, V.; Ritsema, C.; Varela, A.

    2012-04-01

    Cape Verde, located off the coast of Senegal in western Africa, is a volcanic archipelago where a combination of human, climatic, geomorphologic and pedologic factors has led to extensive degradation of the soils. Like other Sahelian countries, Cape Verde has suffered the effects of desertification through the years, threatening the livelihood of the islands population and its fragile environment. In fact, the steep slopes in the ore agricultural islands, together with semi-arid and arid environments, characterized by an irregular and poorly distributed rainy season, with high intensity rainfall events, make dryland production a challenge. To survive in these fragile conditions, the stabilization of the farming systems and the maintenance of sustainable yields have become absolute priorities, making the islands an erosion control laboratory. Soil and water conservation strategies have been a centerpiece of the government's agricultural policies for the last half century. Aiming to maintain the soil in place and the water inside the soil, the successive governments of Cape Verde have implemented a number of soil and water conservation techniques, the most common ones being terraces, half moons, live barriers, contour rock walls, contour furrows and microcatchments, check dams and reforestation with drought resistant species. The soil and water conservation techniques implemented have contributed to the improvement of the economical and environmental conditions of the treated landscape, making crop production possible, consequently, improving the livelihood of the people living on the islands. In this paper, we survey the existing soil and water conservation techniques, analyze their impact on the livelihood condition of the population through a thorough literature review and field monitoring using a semi-quantitative methodology and evaluate their effectiveness and impact on crop yield in the Ribeira Seca watershed. A brief discussion is given on the cost and

  13. Sea level changes during the last and present interglacials in Sal Island (Cape Verde archipelago)

    NASA Astrophysics Data System (ADS)

    Zazo, C.; Goy, J. L.; Hillaire-Marcel, C.; Dabrio, C. J.; González-Delgado, J. A.; Cabero, A.; Bardají, T.; Ghaleb, B.; Soler, V.

    2010-07-01

    Last interglacial and Holocene deposits are particularly well developed in the southern parts of Sal Island (Cape Verde Archipelago). They primarily consist of low-elevation (≤ 2 m above sea level [a.s.l.]) marine deposits made of a basal conglomerate embedded in carbonate mud, passing upwards to calcarenites. All deposits contain an abundant fauna with corals, algae and molluscs with Strombus latus Gmelin and accompanying warm water species of the "Senegalese" fauna. Small scale geomorphological mapping with detailed morphosedimentary analysis revealed lateral facies changes and imbricate (offlapping) structures that suggest small-scale oscillations of paleo-sealevels during high sea stand intervals. U-series measurements (in coral fragments) allowed unequivocal identification of Marine Isotope Substage (MIS) 5.5 units, but were not precise enough to date the sea level oscillations of the interval. However, geomorphological data and sedimentary facies analysis suggest a double sea level highstand during the peak of the last interglacial. MIS 5.5 age deposits occur at Sal and the Canary Islands at low topographic elevations, between 1 and 2 masl. However, these values are lower than the elevations measured for the correlative terraces outcropping at the western tropical Atlantic islands, widely considered to be tectonically stable. Combining the results in this paper with earlier investigations of the "Senegalese" fauna distribution as far north as the Mediterranean basin, it is suggested that the last-interglacial oceanic temperatures in this basin, as well as the temperatures in other islands of the Eastern Atlantic and the coasts of Morocco, were warmer than modern temperatures.

  14. Origin of reddening in a paleosol buried by lava flows in Fogo island (Cape Verde)

    NASA Astrophysics Data System (ADS)

    Marques, R.; Prudêncio, M. I.; Waerenborgh, J. C.; Rocha, F.; Dias, M. I.; Ruiz, F.; Ferreira da Silva, E.; Abad, M.; Muñoz, A. M.

    2014-08-01

    In Fogo island (Cape Verde), a buried paleosol with a reddened topsoil developed on mafic lapilli, intercalated between intrusive carbonatites and an alkaline lava flow, was studied. Significant mineralogical, crystalchemistry and chemical variations were found along the profile. Upwards a decrease of the grain size occurs. Increasing weathering of magnetite to maghemite, and ultimately to hematite is also clearly observed. The Fe3+/Fe2+ ratio in silicate phases increases, along with an increase of illite proportion in the mixed-layer I-Sm. Discrete smectite was detected only in the bottom level related with weak drainage conditions. In the upper level there is a significant gain of Na, Cr, P, Si, and particularly As. The colour variations (towards the paleosurface: dark reddish brown - yellowish brown - red - weak red) are mainly due to the fine fraction of the various levels. Hematite is the main iron phase responsible for the colour and may explain the significant retention of Cr, P, As and LREE in the topsoil. Here hematite is more abundant and occurs as larger-sized particles than in the lower levels. This hematite grain growth is probably due to the thermal effect of the overlying hot volcanic unit. Thus the main alteration processes of the lapilli deposits appear to have been (i) weathering mechanisms in arid environment with the formation of an incipient paleosol, and (ii) thermal metamorphism due to the overlying lava contributing for reddening and cementation of the upper levels. Biological remains are absent due to the paleoenvironmental conditions and/or to the effect of heating.

  15. Dealing with variability in water availability: the case of the Verde Grande River basin, Brazil

    NASA Astrophysics Data System (ADS)

    Collischonn, B.; Lopes, A. V.; Pante, A. R.

    2014-09-01

    This paper presents a water resources management strategy developed by the Brazilian National Water Agency (ANA) to cope with the conflicts between water users in the Verde Grande River basin, located at the southern border of the Brazilian semi-arid region. The basin is dominated by water-demanding fruit irrigation agriculture, which has grown significantly and without adequate water use control, over the last 30 years. The current water demand for irrigation exceeds water availability (understood as a 95 % percentile of the flow duration curve) in a ratio of three to one, meaning that downstream water users are experiencing more frequent water shortages than upstream ones. The management strategy implemented in 2008 has the objective of equalizing risk for all water users and consists of a set of rules designed to restrict water withdrawals according to current river water level (indicative of water availability) and water demand. Under that rule, larger farmers have proportionally larger reductions in water use, preserving small subsistence irrigators. Moreover, dry season streamflow is forecasted at strategic points by the end of every rainy season, providing evaluation of shortage risk. Thus, water users are informed about the forecasts and corresponding restrictions well in advance, allowing for anticipated planning of irrigated areas and practices. In order to enforce restriction rules, water meters were installed in all larger water users and inefficient farmers were obligated to improve their irrigation systems' performance. Finally, increases in irrigated area are only allowed in the case of annual crops and during months of higher water availability (November to June). The strategy differs from convectional approached based only on water use priority and has been successful in dealing with natural variability of water availability, allowing more water to be used in wet years and managing risk in an isonomic manner during dry years.

  16. Biochemical Indices and Life Traits of Loggerhead Turtles (Caretta caretta) from Cape Verde Islands

    PubMed Central

    Vieira, Sara; Martins, Samir; Hawkes, Lucy A.; Marco, Adolfo; Teodósio, M. Alexandra

    2014-01-01

    The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and

  17. Depositional history of organic contaminants on the Palos Verdes Shelf, California

    USGS Publications Warehouse

    Eganhouse, R.P.; Pontolillo, J.

    2000-01-01

    During more than 60 years, sedimentation on the Palos Verdes Shelf has been dominated by time-varying inputs of municipal wastewater from the Los Angeles County Sanitation Districts (LACSD) and debris from the Portuguese Bend Landslide (PBL). The present study examines the depositional history of wastewater-derived organic contaminants at a site approximately 6-8 km downcurrent from the outfall system. Sediments at this location are impacted by contributions from both sources, but the relative influence of the sources has changed over time. Two classes of hydrophobic organic contaminants (chlorinated hydrocarbons, long-chain alkylbenzenes) were determined in sediment cores collected in 1981 and 1992. Using molecular stratigraphy, we determined average sedimentation rates (cm/year) and mass accumulation rates (g cm-2 year-1) for the following periods: 1955-1965, 1965-1971, 1971-1981 and 1981-1992. The results show that sedimentation and mass accumulation rates increased from 1955 to 1971 and decreased from 1971 to 1981. These trends are consistent with historical information on the emission of suspended solids from the outfall system, indicating that the discharge of wastes dominated sedimentation at the site during this period. In the 1980s and early 1990s, however, mass accumulation rates increased in spite of continually decreasing emissions of wastewater solids. Several lines of evidence indicate that this increase was due to mobilization of debris from the PBL during and after unusually strong winter storms in the 1980s. As a result, heavily contaminated sediments deposited during the years of greatest waste emissions (i.e. 1950-1970) have been buried to greater sub-bottom depths, thereby reducing their availability for mobilization to the overlying water column. These results highlight the dynamic nature of sedimentation in contaminated coastal ecosystems and its importance to the long-term fate and effects of toxic substances.

  18. Comparison of estimates of evapotranspiration and consumptive use in Palo Verde Valley, California

    USGS Publications Warehouse

    Raymond, Lee H.; Owen-Joyce, Sandra J.

    1987-01-01

    Estimates of evapotranspiration and consumptive use by vegetation in Palo Verde Valley, California, were compared for calendar years 1981 to 1984. Vegetation types were classified, and the areas covered by each type were computed from Landsat satellite digital-image analysis. Evapotranspiration was calculated by multiplying the area of each vegetation type by a corresponding water use rate adjusted for year-to-year variations in climate. The vegetation classification slightly underestimates the total vegetated area when compared to crop reports, because not all multiple cropping could be identified. The accuracy of evapotranspiration calculated from vegetation classification depends primarily on the correct classification of alfalfa and cotton because alfalfa and cotton have larger acreages and use more water/acre than the other crops in the valley. Consumptive use was calculated using a water budget for each of the 4 years. Estimates of evapotranspiration and consumptive use by vegetation, respectively, were: (1) 439,400 and 483,500 acre-ft in 1981, (2) 430,700 and 452,700 acre-ft in 1982, (3) 402,000 and 364,400 acre-ft in 1983, and (4) 406,700 and 373,800 acre-ft in 1984. Evapotranspiration estimates were lower than consumptive use estimates in 1981 and 1982 and higher in 1983 and 1984. Both estimates were lower in 1983 and 1984 than in 1981 and 1982. Yearly differences in estimates correspond most closely to significant changes in stage of the lower Colorado River caused by flood control releases in 1983 and 1984 and to changes in cropping practices. (Author 's abstract)

  19. Hydrographic and particle distributions over the Palos Verdes continental shelf: Spatial, seasonal and daily variability

    USGS Publications Warehouse

    Jones, B.H.; Noble, M.A.; Dickey, T.D.

    2002-01-01

    Moorings and towyo mapping were used to study the temporal and spatial variability of physical processes and suspended particulate material over the continental shelf of the Palos Verdes Peninsula in southwestern Los Angeles, California during the late summer of 1992 and winter of 1992-93. Seasonal evolution of the hydrographic structure is related to seasonal atmospheric forcing. During summer, stratification results from heating of the upper layer. Summer insolation coupled with the stratification results in a slight salinity increase nearsurface due to evaporation. Winter cooling removes much of the upper layer stratification, but winter storms can introduce sufficient quantities of freshwater into the shelf water column again adding stratification through the buoyancy input. Vertical mixing of the low salinity surface water deeper into the water column decreases the sharp nearsurface stratification and reduces the overall salinity of the upper water column. Moored conductivity measurements indicate that the decreased salinity persisted for at least 2 months after a major storm with additional freshwater inputs through the period. Four particulate groups contributed to the suspended particulate load in the water column: phytoplankton, resuspended sediments, and particles in treated sewage effluent were observed in every towyo mapping cruise; terrigenous particles are introduced through runoff from winter rainstorms. Terrigenous suspended particulate material sinks from the water column in <9 days and phytoplankton respond to the stormwater input of buoyancy and nutrients within the same period. The suspended particles near the bottom have spatially patchy distributions, but are always present in hydrographic surveys of the shelf. Temporal variations in these particles do not show a significant tidal response, but they may be maintained in suspension by internal wave and tide processes impinging on the shelf. ?? 2002 Elsevier Science Ltd. All rights reserved.

  20. Investigating volcanic hazard in Cape Verde Islands through geophysical monitoring: network description and first results

    NASA Astrophysics Data System (ADS)

    Faria, B.; Fonseca, J. F. B. D.

    2014-02-01

    We describe a new geophysical network deployed in the Cape Verde Archipelago for the assessment and monitoring of volcanic hazards as well as the first results from the network. Across the archipelago, the ages of volcanic activity range from ca. 20 Ma to present. In general, older islands are in the east and younger ones are in the west, but there is no clear age progression of eruptive activity as widely separated islands have erupted contemporaneously on geological timescales. The overall magmatic rate is low, and there are indications that eruptive activity is episodic, with intervals between episodes of intense activity ranging from 1 to 4 Ma. Although only Fogo Island has experienced eruptions (mainly effusive) in the historic period (last 550 yr), Brava and Santo Antão have experienced numerous geologically recent eruptions, including violent explosive eruptions, and show felt seismic activity and geothermal activity. Evidence for recent volcanism in the other islands is more limited and the emphasis has therefore been on monitoring of the three critical islands of Fogo, Brava and Santo Antão, where volcanic hazard levels are highest. Geophysical monitoring of all three islands is now in operation. The first results show that on Fogo, the seismic activity is dominated by hydrothermal events and volcano-tectonic events that may be related to settling of the edifice after the 1995 eruption; in Brava by volcano-tectonic events (mostly offshore), and in Santo Antão by volcano-tectonic events, medium-frequency events and harmonic tremor. Both in Brava and in Santo Antão, the recorded seismicity indicates that relatively shallow magmatic systems are present and causing deformation of the edifices that may include episodes of dike intrusion.

  1. Investigating volcanic hazard in Cape Verde Islands through geophysical monitoring: network description and first results

    NASA Astrophysics Data System (ADS)

    Faria, B.; Fonseca, J. F. B. D.

    2013-09-01

    We describe a new geophysical network deployed in the Cape Verde archipelago for the assessment and monitoring of volcanic hazards, and the first results from the network. Across the archipelago, the ages of volcanic activity range from ca. 20 Ma to present. In general, older islands are in the east and younger ones are in the west, but there is no clear age progression and widely-separated islands have erupted contemporaneously on geological time scales. The overall magmatic rate is low, and there are indications that eruptive activity is episodic, with intervals between episodes of intense activity ranging from 1 to 4 Ma. Although only Fogo island has experienced eruptions (mainly effusive) in the historic period (last 550 yr), Brava and Santo Antão have experienced numerous geologically recent eruptions including violent explosive eruptions, and show felt seismic activity and geothermal activity. Evidence for recent volcanism in the other islands is more limited and the emphasis has therefore been on monitoring of the three critical islands of Fogo, Brava and Santo Antão, where volcanic hazard levels are highest. Geophysical monitoring of all three islands is now in operation. The first results show that in Fogo the seismic activity is dominated by hydrothermal events and volcano-tectonic events that may be related to settling of the edifice after the 1995 eruption; in Brava by volcano-tectonic events (mostly offshore), and in Santo Antão by volcano-tectonic events, medium frequency events and harmonic tremor. Both in Brava and in Santo Antão, the recorded seismicity indicates that relatively shallow magmatic systems are present and causing deformation of the edifices that may include episodes of dike intrusion.

  2. Evidence for a Mega-Tsunami Generated by Giant Flank Collapse of Fogo Volcano, Cape Verde

    NASA Astrophysics Data System (ADS)

    Ramalho, R. S.; Madeira, J.; Helffrich, G. R.; Schaefer, J. M.; Winckler, G.; Quartau, R.; Adena, K.

    2013-12-01

    Mega-tsunamis generated by ocean island flank collapses are expected to be some of the most hazardous forces of nature, yet evidence for their near-source effects and inferred high run-ups so far is scarce or hotly debated. A newly discovered deposit on the northern coast of Santiago Island (Cape Verde), however, documents the magnitude and run-up height associated with this kind of event. Additionally to chaotic conglomerates distributed from sea-level up to 100 m elevation standing on slopes as steep as 20°, the deposit comprises a number of scattered megaclasts of submarine lava flows, limestone and tuff. The megaclasts are presently located over a higher substructural slope built on younger subaerial lava flows and at elevations ranging 160-220 m a.s.l. All megaclasts correspond to lithologies that crop out exclusively in nearby cliff faces. The origin of this deposit is consequently attributed to an exceptional wave that plucked blocks from the cliff face, transported them inland and deposited them over the higher slopes of the volcanic edifice. The distribution of the megaclasts, together with the local geomorphology, is in agreement with a tsunami that approached the island edifice from the west and was refracted along its northern flank, flooding a series of northwest-oriented valleys. This suggests that the well-known flank collapse of Fogo volcano, located 55 km west of Santiago, is the most likely source, a hypothesis being tested with surface exposure dating. The inferred run-up exceeded 200 m and is consistent with numerical simulations by Paris et al. 2011, implying that the present Fogo island morphology probably developed by at least one giant flank collapse with devastating near-source effects.

  3. Flank collapse triggered by intrusion: the Canarian and Cape Verde Archipelagoes

    NASA Astrophysics Data System (ADS)

    Elsworth, Derek; Day, Simon J.

    1999-12-01

    The potential to develop kilometer-scale instabilities on the flanks of intraplate volcanoes, typified by the Canary and Cape Verde Archipelagoes, is investigated. A primary triggering agent is forced injection of moderate-scale dikes, resulting in the concurrent development of mechanical and thermal fluid pressures along the basal décollement, and magmastatic pressures at the dike interface. These additive effects are shown capable of developing shallow-seated block instabilities for dike thicknesses of the order of 1 m, and horizontal lengths greater than about 1 km. For dikes that approach or penetrate the surface, and are greater in length than this threshold, the destabilizing influence of the magmastatic column is significant, and excess pore fluid pressures may not be necessary to initiate failure. The potentially destabilized block geometry changes from a flank-surface-parallel sliver for short dikes, to a deeper and less stable décollement as dike horizontal length builds and the effects of block lateral restraint diminish. For intrusions longer than about 1 km, the critical basal décollement dives below the water table and utilizes the complementary destabilizing influences of pore fluid pressures and magma "push" at the rear block-scarp. In addition to verifying the plausibility of suprahydrostatic pressures as capable of triggering failure on these volcanoes, timing of the onset of maximum instability may also be tracked. For events within the Cumbre Vieja (1949) and Fogo (1951, 1995) pre-effusive episodes, the observation of seismic activity within the first 1 week to 4 months is consistent with the predictions of thermal and mechanical pressurization.

  4. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    PubMed

    Paiva, Vitor H; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas. Further

  5. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa

    PubMed Central

    Paiva, Vitor H.; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A.

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird—the endangered Cape Verde shearwater Calonectris edwardsii–during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas

  6. Rapid uplift during 2007-2012 at Laguna del Maule volcanic field, Andean Southern Volcanic Zone, Chile

    NASA Astrophysics Data System (ADS)

    Le Mevel, H.; Feigl, K.; Ali, T.; Cordova V., M. L.; DeMets, C.; Singer, B. S.

    2012-12-01

    The Laguna del Maule (LdM) volcanic field includes an unusual concentration of post-glacial rhyolitic lava coulees and domes, dated between 24 to 2 thousand years old that cover more than 100 square kilometers and erupted from 24 vents that encircle a 20-km-diameter lake basin on the range crest. The recent concentration of rhyolite is unparalleled in the Southern Volcanic Zone of the Andes. Moreover, the western portion of the LdM volcanic field has experienced rapid uplift since 2007, leading to questions about the current configuration of the magmatic system and processes that drive the ongoing inflation. We aim to quantify the active deformation of the LdM volcanic field and its evolution with time. To do so, we use interferometric synthetic aperture radar (InSAR) data acquired by three satellite missions: Envisat in 2003 and 2004, ALOS between 2007 and 2010, and TerraSAR-X in 2012. An interferogram spanning March 2003 to February 2004 "shows no deformation" (Fournier et al., 2010). From 2007 through 2012, however, the shortening of the satellite-to-ground distance revealed a range change rate of greater than 200 mm/yr along the radar line of sight. The deformation includes a circular area 20 km in diameter centered on the western portion of the circle of young rhyolite domes. To analyze the InSAR results, we employ the General Inversion for Phase Technique (GIPhT; Feigl and Thurber, 2009; Ali and Feigl, 2012). We have considered several hypotheses to interpret this deformation. Artefacts such as orbital errors, atmospheric perturbations or topographic contribution cannot account for the observed signal. We also reject the hypothesis of uplift due to gravitational unloading of the crust based on our modeling of independently measured lake level variations over the observed time interval. We thus attribute the deformation to the intrusion of magma into the upper crust below the southwest region of the LdM volcanic field. The best fit to the InSAR data is

  7. Crustal deformation and magmatic processes at Laguna del Maule volcanic field (Chile): Geodetic measurements and numerical models

    NASA Astrophysics Data System (ADS)

    Le Mevel, Helene

    The Laguna del Maule (LdM) volcanic field in Chile is an exceptional example of postglacial rhyolitic volcanism in the Southern Volcanic Zone of the Andes. Since 2007, LdM has experienced an unrest episode characterized by high rates of deformation measured by interferometric analysis of synthetic aperture radar (SAR) images acquired between 2007 and 2016, and data from the Global Positioning System (GPS) recorded since 2012 at five stations. The inflating region includes most of the 16--km-by--14--km ring of rhyolitic domes and coulees. The fastest-moving GPS station (MAU2) has a velocity vector of [[special character omited]72 +/- 4, 19 +/- 1, 194 +/- 3] mm/yr between 2012 and 2016 for the eastward, northward, and upward components, respectively. First, we model the InSAR observations assuming a rectangular dislocation in a half space with uniform elastic properties. The best time function for modeling the InSAR data set is a double exponential model with rates increasing from 2007 through 2010 and decreasing slowly since 2011. Modeling of historical uplift at Yellowstone, Long Valley, and Three Sisters volcanic fields suggests a common temporal evolution of vertical displacement rates. We hypothesize that magma intruding into an existing silicic magma reservoir is driving the surface deformation and present a new dynamic model to describe this process. A Newtonian fluid characterized by its viscosity, density, and pressure flows through a vertical conduit, intruding into a reservoir embedded in an elastic domain and leading to time-dependent surface deformation. Using a grid-search optimization, we minimize the misfit to the InSAR displacement data by varying the three parameters governing the analytical solution: the characteristic timescale tauP for magma propagation, the injection pressure, and the inflection time when the acceleration switches from positive to negative. For a spheroid with semi-major axis a = 6200 m, semi-minor axis c = 100 m, located at a

  8. A Millennial Length High-Resolution Pollen, Charcoal, Diatom and Stable Isotope Record from Laguna San Carlos, Panama

    NASA Astrophysics Data System (ADS)

    St Jacques, J. M.; Escobar, J.; Velez, M.; Correa-Metrio, A.; Curtis, J. H.

    2014-12-01

    We report here on preliminary results from Laguna San Carlos, (8o 37' 32.44''N, 80o 03' 04.24'' W) a small, shallow (8.3 m) volcanic lake from west-central Panama, a relatively unstudied Pacific coast region that is an important location for paleo-ENSO studies. The circular lake is a closed basin lake with a gradually sloping shoreline located within a caldera. The 300 cm core was taken in 2 m of water during March 2010. The core bottom was resting upon basement granitic rock with feldspar phenocrystals. The chronology is based upon five radiocarbon dates from terrestrial plant and wood remains. Pollen and charcoal were sampled at 10 cm resolution, diatoms at 5 cm and stable isotopes at 1 cm. The pollen profile shows four distinct terrestrial vegetation units. During the Medieval Climate Anomaly (MCA), from AD 880-1485, the vegetation was sparse with high amounts of grass, Asteraceae and charcoal suggestive of grasslands with high rates of natural disturbance, including fire. With the onset of the Little Ice Age (LIA), during AD 1485-1570, the vegetation transitioned into an open dry forest characterized by Myrica and Anacardium with high seasonality in precipitation. At AD 1570, the climate became wetter as shown by the pollen typical of a moist tropical forest. This lasted until AD 1720 when a period of greater human disturbance began (as shown by increased sedimentation rates), with primary forest taxa cohabiting with grasses and secondary taxa. The first maize pollen appeared at ~AD 1700. The diatom record is dominated by a single eutrophic species, Fragilaria crotonensis; however from AD 880-1150 minor taxa such as Aulacoseira spp., indicative of increased turbulence appeared, supporting the pollen record of open canopy vegetation at this time. The sedimentary carbon/nitrogen ratio (C/N) shows that the majority of the organic remains in the lake have always come from the surrounding basin. MTM spectral analysis of percent Fragilaria crotonensis, percent carbon

  9. Magnitude, geomorphologic response and climate links of lake level oscillations at Laguna Potrok Aike, Patagonian steppe (Argentina)

    NASA Astrophysics Data System (ADS)

    PASADO science Team Kliem, P.; Buylaert, J. P.; Hahn, A.; Mayr, C.; Murray, A. S.; Ohlendorf, C.; Veres, D.; Wastegård, S.; Zolitschka, B.

    2013-07-01

    Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted.Abrasion and lake level oscillations since at least ˜50 ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1 km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to ˜45 ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40 m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5 ka.Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift

  10. Magnitude, geomorphologic response and climate links of lake level oscillations at Laguna Potrok Aike, Patagonian steppe (Argentina)

    NASA Astrophysics Data System (ADS)

    Kliem, P.; Buylaert, J. P.; Hahn, A.; Mayr, C.; Murray, A. S.; Ohlendorf, C.; Veres, D.; Wastegård, S.; Zolitschka, B.; The Pasado Science Team

    2013-07-01

    Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted. Abrasion and lake level oscillations since at least ˜50 ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1 km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to ˜45 ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40 m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5 ka. Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift

  11. Rocas Verdes Ophiolite Complexes in the Southernmost Andes: Remnants of the Mafic Igneous Floor of a Back-arc Basin that Rifted the South American Continental Crust in the Late Jurrassic and Early Cretaceous

    NASA Astrophysics Data System (ADS)

    Stern, C. R.

    2001-12-01

    The Rocas Verdes are an en echelon group of late Jurassic and early Cretaceous igneous complexes in the southernmost Andes. They consist of mafic pillow lavas, dikes and gabbros interpreted as the upper portions of ophiolite complexes formed along mid-ocean-ridge-type spreading centers. When secondary metamorphic affects are accounted for, the geochemistry of mafic Rocas Verdes rocks are similar to ocean-ridge basalts (MORB). The spreading centers that generated the Rocas Verdes rifted the southwestern margin of the Gondwana continental crust, during the start of break-up in the southern Atlantic, to form the igneous floor of a back-arc basin behind a contemporaneous convergent plate boundary magmatic arc. Late Jurassic and early Cretaceous sediments from both the magmatic arc on the southwest and the continental platform on the northeast of the basin were deposited in the Rocas Verdes basin, and these sediments are interbedded with mafic pillow lavas along the margins of the Rocas Verdes mafic complexes. Also, mafic dikes and gabbros intrude older pre-Andean and Andean lithologies along both flanks of the Rocas Verdes, and leucocratic country rocks are engulfed in the Rocas Verdes mafic complexes. These relations indicate that the Rocas Verdes complexes formed in place and are autochthonous, having been uplifted but not obducted, which may explain the lack of exposure of the deeper ultramafic units. Zircon U/Pb ages of 150+/-1 Ma for the Larsen Harbour Formation, a southern extension of the Rocas Verdes belt on South Georgia Island, and 138+/-2 Ma for the Sarmiento complex, the northernmost in the Rocas Verdes belt, indicate that this basin may have formed by "unzipping" from the south to the north, with the southern portion beginning to form earlier and developing more extensively than the northern portion of the basin. Paleomagnetic data suggest that the Rocas Verdes basin developed in conjunction with the displacement of the Antarctic Peninsula and opening of

  12. Phylogenetic and phylogeographic evidence for a Pleistocene disjunction between Campanula jacobaea (Cape Verde Islands) and C. balfourii (Socotra).

    PubMed

    Alarcón, Marisa; Roquet, Cristina; García-Fernández, Alfredo; Vargas, Pablo; Aldasoro, Juan José

    2013-12-01

    Our understanding of processes that led to biogeographic disjunct patterns of plant lineages in Macaronesia, North Africa and Socotra remains poor. Here, we study a group of Campanula species distributed across these areas integrating morphological and reproductive traits with phylogenetic and phylogeographic data based on the obtention of sequences for 4 highly variable cpDNA regions and AFLP data. The phylogeny obtained shows a sister relationship between Campanula jacobaea (endemic to Cape Verde Islands) and C. balfourii (endemic to Socotra), thus revealing a striking disjunct pattern (8300 km). These species diverged around 1.0 Mya; AFLP and haplotype data suggest that no genetic interchange has occurred since then. Their closest taxon, C. hypocrateriformis, is endemic to SW Morocco. The archipelagos of Macaronesia and Socotra have probably acted as refugia for North-African species, leading to speciation through isolation. Although C. balfourii has a restricted distribution, its genetic variability suggests that its populations have suffered no bottlenecks. C. jacobaea is also genetically rich and its distribution across Cape Verde Islands seems to have been influenced by the NE-SW trade winds, which may also have favoured the admixture found among the populations of the three southern islands. Floral features of the morphologically hypervariable C. jacobaea were also measured to assess whether the taxon C. bravensis, described for some of the southeast populations of C. jacobaea, corresponds to a different evolutionary entity. We show that morphological variation in C. jacobaea does not correspond to any genetic or geographic group. PMID:23835079

  13. Unmatched Case-Control Study on Late Presentation of HIV Infection in Santiago, Cape Verde (2004-2011).

    PubMed

    Moreira, António L; Fronteira, Inês; Figueiredo Augusto, Gonçalo; Martins, Maria Rosario O

    2016-03-01

    Access to free antiretroviral therapy (ART) in Sub-Saharan Africa has been steadily increasing over the past decade. However, the success of large-scale ART programmes depends on timely diagnosis and early initiation of HIV care. This study characterizes late presenters to HIV care in Santiago (Cape Verde) between 2004 and 2011, and identifies factors associated with late presentation for care. We defined late presentation as persons presenting to HIV care with a CD4 count below 350 cells/mm³. An unmatched case-control study was conducted using socio-demographic and behavioural data of 368 individuals (191 cases and 177 controls) collected through an interviewer-administered questionnaire, comparing HIV patients late and early presented to care. Logistic regression was performed to estimate odds ratio and 95% confidence intervals. Results show that 51.9% were late presenters for HIV. No differences were found in gender distribution, marital status, or access to health services between cases and controls. Participants who undertook an HIV test by doctor indication were more likely to present late compared with those who tested for HIV by their own initiative. Also, individuals taking less time to initiate ART are more likely to present late. This study highlights the need to better understand reasons for late presentation to HIV care in Cape Verde. People in older age groups should be targeted in future approaches focused on late presenters to HIV care. PMID:26999167

  14. Unmatched Case-Control Study on Late Presentation of HIV Infection in Santiago, Cape Verde (2004–2011)

    PubMed Central

    Moreira, António L.; Fronteira, Inês; Augusto, Gonçalo Figueiredo; Martins, Maria Rosario O.

    2016-01-01

    Access to free antiretroviral therapy (ART) in Sub-Saharan Africa has been steadily increasing over the past decade. However, the success of large-scale ART programmes depends on timely diagnosis and early initiation of HIV care. This study characterizes late presenters to HIV care in Santiago (Cape Verde) between 2004 and 2011, and identifies factors associated with late presentation for care. We defined late presentation as persons presenting to HIV care with a CD4 count below 350 cells/mm3. An unmatched case-control study was conducted using socio-demographic and behavioural data of 368 individuals (191 cases and 177 controls) collected through an interviewer-administered questionnaire, comparing HIV patients late and early presented to care. Logistic regression was performed to estimate odds ratio and 95% confidence intervals. Results show that 51.9% were late presenters for HIV. No differences were found in gender distribution, marital status, or access to health services between cases and controls. Participants who undertook an HIV test by doctor indication were more likely to present late compared with those who tested for HIV by their own initiative. Also, individuals taking less time to initiate ART are more likely to present late. This study highlights the need to better understand reasons for late presentation to HIV care in Cape Verde. People in older age groups should be targeted in future approaches focused on late presenters to HIV care. PMID:26999167

  15. Prevalence of Anaemia and Associated Factors among Children below Five Years of Age in Cape Verde, West Africa

    PubMed Central

    Semedo, Rosa M.L.; Santos, Marta M.A.S.; Baião, Mirian R.; Luiz, Ronir R.

    2014-01-01

    ABSTRACT This study estimated the prevalence of anaemia and associated factors in a probability sample of 993 children aged 6-59 months in Cape Verde, West Africa. Odds ratio (OR) and 95% confidence interval (95% CI) were estimated from a hierarchical model for multiple analysis to assess the association between anaemia and explanatory variables. The prevalence of anaemia was 51.8% (95% CI 47.7-55.8). Children who resided within poor household conditions (OR 1.99; 95% CI 1.06-3.71) were below 24 months of age (OR 3.23; 95% CI 2.03-5.15) and recently experienced diarrhoea (OR 1.58; 95% CI 0.99-2.50) were at high risk of anaemia. Anaemia should be considered a serious public-health concern in Cape Verde, mainly for children below 24 months. Further, special consideration should be given to children who have experienced recent diarrhoea and belong to families residing in poor household conditions. PMID:25895198

  16. Reformatted data sets used in the Cooperative LACSD/USGS Palos Verdes Flow Study, 2000--2008

    USGS Publications Warehouse

    Anderson, Todd; Rosenberger, Kurt J.; Gartner, Anne L.

    2012-01-01

    Beginning in 1997, the Environmental Protection Agency (EPA) defined a contaminated section of the Palos Verdes shelf in southern California as a Superfund site, initiating a continuing investigation of this area. A number of agencies, including the EPA, U.S. Geological Survey (USGS), and Science Applications International Corporation (SAIC), conducted two oceanographic measurement programs in 2004 and 2007-2008 (SAIC, 2004, 2005; Rosenberger and others, 2010; Sherwood and others, unpublished data) to improve our understanding of the natural processes that resuspend and transport sediment in the area, especially in the region southeast of the Whites Point ocean outfall where earlier measurements were thought to be deficient. Los Angeles County Sanitation Districts (LACSD) deployed a simpler but much broader array of instruments on the Palos Verdes shelf and within the northern reaches of San Pedro Bay from 2000 to 2008 in order to characterize the current and temperature patterns within these regions. This program overlapped the two programs run by USGS and other agencies in 2004 and 2007. The LACSD data were made available to the USGS and the EPA in order to support their joint efforts to model the transport of the contaminated sediments in the region. This report describes the LACSD data sets, the instruments and data-processing procedures used, and the archive that contains the data sets that have passed our quality-assurance procedures.

  17. High-resolution Late Pleistocene paleomagnetic secular variation record from Laguna Potrok Aike, Southern Patagonia (Argentina): preliminary results from the ICDP-PASADO drilling

    NASA Astrophysics Data System (ADS)

    Lisé-Pronovost, Agathe; St-Onge, Guillaume; Haberzettl, Torsten; Pasado Science Team

    2010-05-01

    High-resolution paleomagnetic reconstructions from sedimentary sequences are scarce in the Southern Hemisphere. Therefore, the millennial- to centennial-scale variability of the geomagnetic field is under-represented in the Southern Hemisphere relative to the Northern Hemisphere and the possible global nature of that variability cannot be assessed. Here we present the first high-resolution Late Pleistocene paleomagnetic secular variation (PSV) reconstruction from the continental archive Laguna Potrok Aike south of 42°S in South America. Laguna Potrok Aike (51°58'S, 70°23'W) is a maar lake located in the Pali Aike Volcanic Field in southern Patagonia (Argentina). Previous studies revealed very high Holocene sedimentation rates (> 100 cm/ka) in the center of the lake. During the austral spring 2008, the multi-national Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) science team drilled two ~100 m holes under the framework of the International Continental scientific Drilling Program (ICDP). A preliminary Holocene age model based on comparison of magnetic susceptibility data from the PASADO core with the well-dated (radiocarbon- and tephra-based chronology) core located nearby in the center of the lake (PTA03-12) indicates a continuous deposition of ~19 m of lacustrine sediments since the last 16 ka cal. BP. Hysteresis measurements using an alternating gradient force magnetometer indicate a magnetic assemblage dominated by magnetite grains in the pseudo-single domain range. Principal component analysis (PCA) inclination and declination profiles were constructed from the stepwise alternating field demagnetization of the natural remanent magnetization (NRM) measured on u-channels at 1 cm intervals using a 2G Enterprises cryogenic magnetometer. The PCA inclinations vary around the expected geocentric axial dipole (GAD) inclination for the latitude of the coring site and the maximum angular deviation (MAD) values are generally lower than 5°, indicating

  18. A Century-long Record of Radiocarbon in the Waters of the Cape Verde Islands in the Tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Fernandez-Bremer, A.; Rosenheim, B. E.; Swart, P. K.

    2011-12-01

    Radiocarbon measurements in corals and sclerosponges have been used to reconstruct ocean ventilation and water mass circulation changes in the oceans. Although beneficial in enriching the time resolution of such information, coral and sclerosponge records can be quite spatially sparse. Here, we present a century-long Δ14C record from Siderastrea radians collected in the surface waters of the Cape Verde Islands. The islands are located close to the salinity maximum waters (SMWs) of N. Atlantic, the source of both subsurface waters of the interior Caribbean and latent heat to the mid-latitude atmosphere. Thus, radiocarbon records from this location may be used to probe changes in the size and location of the SMWs. The age corrected Δ14C data reported here were calculated on the basis of annual density bands and the annual cycle in δ18O (Moses et al., 2006), and show that the waters around the Cape Verde Islands are depleted in Δ14C relative to the SMWs and the western boundary currents of the North Atlantic subtropical gyre due to the upwelling of older, Δ14C depleted waters, near the West African coast and off of the islands proper. The average pre-bomb Δ14C in Cape Verde is -50.3 ± 5.3 % (1σ), and the post-bomb Δ14C average is 58.9 ± 9 % (1σ). To date, these post-bomb measurements constitute the most depleted Δ14C values reported for any corals in the Atlantic Ocean (e.g. Bermuda Δ14C = 147 ± 8.3 %, Florida Δ14C = 153 ± 5.13 %, Puerto Rico Δ14C = 128 ± 10.9 %; Druffel 1989, Kilbourne et al., 2007) and confirm earlier limited observations from a Porites astreoides hentscheli specimen from the Cape Verde Islands (Druffel 1996). Our coral records a monotonic increase in Δ14C of 10% year-1 during the 1960s. This is generally consistent with a previous estimate of 13 % year-1 (Druffel 1996). This slope is a relative measure of the entrainment of depleted Δ14C waters and of the incorporation of anthropogenic CO2 to the ocean surface. The rate

  19. Reducing volcanic risk on Fogo Volcano, Cape-Verde, through a participatory approach: which out coming?

    NASA Astrophysics Data System (ADS)

    Texier-Teixeira, P.; Chouraqui, F.; Perrillat-Collomb, A.; Lavigne, F.; Cadag, J. R.; Grancher, D.

    2013-11-01

    This research paper presents the outcomes of the Work Package 5 (Socio-economical Vulnerability Assessment and Community-Based Disaster Risk Reduction) of the MIAVITA Research Program (MItigate and Assess risk from Volcanic Impact on Terrain and human Activities) conducted in Fogo Volcano, Cape-Verde. The study lasted for almost 3 yr (May 2010-January 2012) of which most of the time was spent in the village of Chã das Caldeiras, situated within the 9 km-wide caldera of the volcano inside the Fogo Natural Park. The objectives of the program included assessment of the vulnerability of the community at risk in terms of livelihoods, access to resources, and power relations between the local people and the different public and private institutions. These are important factors that need to be investigated in order to understand the root causes of vulnerability of the local people. This case study shows that the voluntary exposure of people at volcanic threats is linked with daily access to sources of livelihood specially agriculture and tourism. This is despite the perception of people of the risk on their lives and properties. In order to counter the factors of vulnerability, the study also aimed to identify and enhance local capacities. To achieve such objective, a Participatory 3-Dimensional Mapping (P3DM) activity was conducted to facilitate the dialogue between the local people and the different stakeholders as well as to prepare plans and measures to reduce volcanic risk. The P3DM was a half success considering that it has not yet led to an operational plan which takes into account the local capacities. The main reasons included (1) the non-participative aspect of the project at the beginning which should have identified priorities for people and let them lead the project to ensure the sustainability (2) deep conflicts within the community which complicated the focus group discussions around the 3-D map, and the difficulties to involve more marginalized people

  20. Reducing volcanic risk on Fogo Volcano, Cape Verde, through a participatory approach: which outcome?

    NASA Astrophysics Data System (ADS)

    Texier-Teixeira, P.; Chouraqui, F.; Perrillat-Collomb, A.; Lavigne, F.; Cadag, J. R.; Grancher, D.

    2014-09-01

    This research paper presents the outcomes of Work Package 5 (socio-economical vulnerability assessment and community-based disaster risk reduction) of the MIAVITA (MItigate and Assess risk from Volcanic Impact on Terrain and human Activities) research programme conducted on Fogo Volcano, Cape Verde. The study lasted for almost 3 years (May 2010 to January 2012), of which most of the time was spent in the village of Chã das Caldeiras, situated within the 9 km wide caldera of the volcano inside Fogo Natural Park. The objectives of the programme included assessment of the vulnerability of the community at risk in terms of livelihoods, access to resources, and power relations between the local people and the different public and private institutions. These are important factors that need to be investigated in order to understand the root causes of vulnerability of the local people. This case study shows that the voluntary exposure of people to volcanic threats is linked to daily access to sources of livelihood, especially agriculture and tourism. This is despite the perception of people of the risk to their lives and properties. In order to counter the factors of vulnerability, the study also aimed to identify and enhance local capacities. To achieve such an objective, a participatory three-dimensional mapping (P3DM) activity was conducted to facilitate the dialogue between the local people and the different stakeholders as well as to prepare plans and measures to reduce volcanic risk. The P3DM was a half success considering that it has not yet led to an operational plan which takes into account the local capacities. The main reasons included (1) the non-participatory aspect of the project at the beginning which should have identified priorities for people and let them lead the project to ensure the sustainability of (2) deep conflicts within the community which complicated the focus group discussions around the 3-D map, and the difficulties in involving more

  1. Macromorphologic analysis of paleosols in the Campina Verde and Uberaba regions - Minas Gerais, Brazil

    NASA Astrophysics Data System (ADS)

    Doce, Rafael; Ladeira, Francisco

    2015-04-01

    The Bauru Basin is a Cretaceous inner basin with 370.000 square kilometers, situated inside the Parana's Basin and deposited on the basalt of the Serra Geral Formation. The Bauru Basin is characterized by its alluvial fans and different formations of Bauru and Caiuá Group, which according to Fernandes (1992), join to form the Bauru Basin, but according to Barcelos (1984), the Caiuá Formation fits in the same group of Bauru, and doesn't form another group apart. Among the Bauru Group formations (Adamantina, Araçatuba, Uberaba and Marília - Fernandes and Coimbra, 1996), this study focuses on the Marilia Formation, the last to be deposited and therefore, the one that occupies the highest part of the stratigraphic column of the Bauru Group. According to Suguio (1975), the Marilia Formation sedimentation has occurred in a restricted fogging, under torrential regimes of alluvial fans with deposition associated to detrital floors, during the progressive installation of a semi-arid environment, which has provided the carbonate cementing of its detritus and the development of the caliche and calcrete. This formation is divided into three members (Ponte Alta, Serra da Galga and Echaporã), and consists of coarse to conglomeratic sandstones with a large number of paleosols along its entire thickness. These paleosols are the research object of this study, which aims to study their macromorphology and search for information about the paleogeography and the evolution of the landscape of the Campina Verde and Uberaba regions (Minas Gerais - Brazil), when the pedogenesis of these profiles has developed, in other words, during the Upper Cretaceous (Maasthichtian). This study has resulted in descriptions and analyzes of four different outcrops that contribute to the study of paleosols in the region, whose main feature is the abundance of bioturbation, besides the existence of different levels of calcrete, nodules and carbonate cement, what are the clear evidence of lack of water

  2. Calculating the Diffusive Flux of Persistent Organic Pollutants between Sediments and the Water Column on the Palos Verdes Shelf Superfund Site using Polymeric Passive Samplers

    EPA Science Inventory

    Passive samplers were used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water of a marine Superfund site on the Palos Verdes Shelf, California, USA. Measured concentrations in the porewater and water column at...

  3. Using Passive Samplers to Calculate the Diffusive Flux of DDTs and PCBs from Sediments to Water Column at the Palos Verdes Shelf Superfund Site

    EPA Science Inventory

    Background/Objectives. The Palos Verdes Shelf (PVS) Superfund site is in over 50 meters of water on the continental shelf and slope off the coast of southern California (USA). The site includes over 25 km2 of sediments contaminated over several decades by municipal treatment pla...

  4. Passive Sampling to Measure Baseline Dissolved Persistent Organic Pollutant Concentrations in the Water Column of the Palos Verdes Shelf Superfund Site

    EPA Science Inventory

    Passive sampling was used to deduce water concentrations of persistent organic pollutants (POPs) in the vicinity of a marine Superfund site on the Palos Verdes Shelf, California, USA. Pre-calibrated solid phase microextraction (SPME) fibers and polyethylene (PE) strips that were...

  5. The stratified microbial community at Laguna Figueroa, Baja California, Mexico: A possible model for prephanerozoic laminated microbial communities preserved in cherts

    NASA Astrophysics Data System (ADS)

    Stolz, John F.; Margulis, Lynn

    1984-12-01

    The microbial mat community of the evaporite flat at North Pond, Laguna Figueroa (Baja California, Mexico) was actively involved in the production of laminated sediments prior to 1978. Heavy rains in 1979 and 1980 flooded the mat with 1 and 3 meters of meteoric water respectively. The flooding deposited up to 10 cm of silicoclastic sediment over theMicrocoleus-dominated mat and resulted in the cessation of laminated sediment deposition. In 1982, the surface had been recolonized by species of cyanobacteria (Spirulina, Oscillatoria) and purple photosynthetic bacteria (Chromatium, Thiocapsa). The silicoclastic sediments and residual evaporites, which overlaid the laminated sediment, had been reworked into an anaerobic, sulfide-rich mud and contained well preserved sheaths of filamentous and coccoid bacteria.

  6. Population fluctuations of Pyrodinium bahamense and Ceratium furca (Dinophyceae) in Laguna Grande, Puerto Rico, and environmental variables associated during a three-year period.

    PubMed

    Sastre, Miguel P; Sánchez, Efrain; Flores, Marineé; Astacio, Samuel; Rodríguez, Julianna; Santiago, Melissa; Olivieri, Karina; Francis, Veronica; Núñez, Juan

    2013-12-01

    Bioluminescent bays and lagoons are unique natural environments and popular tourist attractions. However, the bioluminescence in many of these water bodies has declined, principally due to anthropogenic activities. In the Caribbean, the bioluminescence in these bays and lagoons is mostly produced by the dinoflagellate Pyrodinium bahamense var. bahamense. Laguna Grande is one of the three year-round bioluminescent water bodies in Puerto Rico that are known to remain but P. bahamense var. bahamense density fluctuations have not been studied. In this study we describe water quality parameters and density fluctuations of the most common dinoflagellates in Laguna Grande, P. bahamense var. bahamense and Ceratium furca, over a three-year period. For this, three sampling stations were established in Laguna Grande from which water samples were collected in triplicate and analyzed for temperature, phosphates, nitrates, salinity, water transparency, fluorescence, and dinoflagellate densities, at the water surface and at 2m depth, from May 2003 to May 2006. The results showed a density fluctuation pattern for P. bahamense var. bahamense, where higher densities were observed mainly from April to September, and lower densities from October to February. Density fluctuations of C. furca were more erratic and a repetitive pattern was not observed. Densities of P. bahamense var. bahamense ranged from 0.48 to 90978 cells/L and densities of C. furca ranged from 0 to 11,200 cells/L. The mean population density throughout the sampling period was significantly higher in P. bahamense var. bahamense (mean = 18,958.5 cells/L) than in C. furca (mean = 2601.9 cells/L). Population densities of P. bahamense var. bahamense were negatively correlated with C. furca densities during the first year of sampling; however, they were positively correlated during the third year. Non-significant differences between surface and 2m depth samples were observed for temperature, phosphates, nitrates, salinity

  7. Rock-magnetic signature of precipitation and extreme runoff events in south-eastern Patagonia since 51,200 cal BP from the sediments of Laguna Potrok Aike

    NASA Astrophysics Data System (ADS)

    Lisé-Pronovost, A.; St-Onge, G.; Gogorza, C.; Jouve, G.; Francus, P.; Zolitschka, B.

    2014-08-01

    A 106-m long sediment sequence from the maar lake Laguna Potrok Aike in southern Patagonia was recovered in the framework of the International Continental Scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). About half of the sedimentary sequence is composed of mass movement deposits (MMDs) and the event-corrected record reaches back to 51,200 cal BP. Here we present a high-resolution rock-magnetic study revealing two sedimentary facies associated with MMDs and characterized by two different types of spurious gyroremanent magnetization (GRM) acquired during static alternating field demagnetization. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of GRM acquired during demagnetization of the natural remanent magnetization (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of a series of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetization of the isothermal remanent magnetization (IRM). Based on geological, limnological, stratigraphic and climatic evidence these layers are interpreted as reflecting pedogenic hematite and/or goethite brought to the lake by runoff events related to precipitation and permafrost melt. The pedogenic iron minerals mobilized from the catchment most likely settled out of suspension on top of MMDs after a rapid remobilization event. The series of runoff events corresponds to periods of increased lacustrine productivity in Laguna Potrok Aike and are coeval within the limit of the chronology to warm periods of the Last Glacial as recorded in Antarctica, the deglaciation in the mid-latitudes of the Southern Hemisphere and enhanced precipitation during the Early Holocene in southeastern

  8. Analysis of stable isotope ratios (δ18O and δ2H) in precipitation of the Verde River watershed, Arizona 2013 through 2014

    USGS Publications Warehouse

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tucci, Rachel S.

    2016-01-01

    Stable isotope delta values (δ18O and δ2H) of precipitation can vary with elevation, and quantification of the precipitation elevation gradient can be used to predict recharge elevation within a watershed. Precipitation samples were analyzed for stable isotope delta values between 2003 and 2014 from the Verde River watershed of north-central Arizona. Results indicate a significant decrease in summer isotopic values overtime at 3,100-, 4,100-, 6,100-, 7,100-, and 8,100-feet elevation. The updated local meteoric water line for the area is δ2H = 7.11 δ18O + 3.40. Equations to predict stable isotopic values based on elevation were updated from previous publications in Blasch and others (2006), Blasch and Bryson (2007), and Bryson and others (2007). New equations were separated for samples from the Camp Verde to Flagstaff transect and the Prescott to Chino Valley transect. For the Camp Verde to Flagstaff transect, the new equations for winter precipitation are δ18O = -0.0004z − 8.87 and δ2H = -0.0029z − 59.8 (where z represents elevation in feet) and the summer precipitation equations were not statistically significant. For the Prescott to Chino Valley transect, the new equations for summer precipitation are δ18O = -0.0005z − 3.22 and δ2H = -0.0022z − 27.9; the winter precipitation equations were not statistically significant and, notably, stable isotope values were similar across all elevations. Interpretation of elevation of recharge contributing to surface and groundwaters in the Verde River watershed using the updated equations for the Camp Verde to Flagstaff transect will give lower elevation values compared with interpretations presented in the previous studies. For waters in the Prescott and Chino Valley area, more information is needed to understand local controls on stable isotope values related to elevation.

  9. Rock magnetic and geochemical proxies for iron mineral diagenesis in a tropical lake: Lago Verde, Los Tuxtlas, East Central Mexico

    NASA Astrophysics Data System (ADS)

    Ortega, Beatriz; Caballero, Margarita; Lozano, Socorro; Vilaclara, Gloria; Rodríguez, Alejandro

    2006-10-01

    Magnetic and non-magnetic mineral analyses were conducted on a lacustrine sequence from Lago Verde in the tropical coast along the Gulf of Mexico that covers the last 2000 years. The site witnessed the transformation of the environment since the early Olmec societies until forest clearance in the last century. Through these analyses we investigated the processes that affected the magnetic mineralogy in order to construct a model of past environmental changes, and compare this model with the archeological record and inferred climatic changes in the northern hemisphere of tropical America. Volcanic activity has played a major influence on sediment magnetic properties, as a purveyor of Ti-magnetites/Ti-maghemites, and as a factor of instability in the environment. Anoxic reductive conditions are evident in most of Lago Verde's sedimentary record. Direct observations of magnetic minerals and ratios of geochemical (Fe, Ti), and ferrimagnetic ( χf) and paramagnetic ( χp) susceptibility ( χ) data, are used as parameters for magnetite dissolution ( χp/ χ, Fe/ χf), and precipitation ( χf/Ti) of magnetic minerals. Intense volcanic activity and anoxia are recorded before A.D. 20, leading to the formation of framboidal pyrite. Increased erosion, higher evaporation rates, lower lake levels, anoxia and reductive diagenesis in non-sulphidic conditions are inferred for laminated sediments between A.D. 20-850. This deposit matches the period of historical crisis and multiyear droughts that contributed to the collapse of the Maya civilization. Dissolution of magnetite, a high organic content and framboidal pyrite point to anoxic, sulphidic conditions and higher lake levels after A.D. 850. Higher lake levels in Lago Verde broadly coincide with the increased precipitation documented during the Medieval Warm Period (A.D. 950-1350) in the northern tropical and subtropical regions of the American continent. For the Little Ice Age (A.D. 1400-1800), the relatively moist conditions

  10. Molecular and serological surveillance of canine enteric viruses in stray dogs from Vila do Maio, Cape Verde

    PubMed Central

    2014-01-01

    Background Infections caused by canine parvovirus, canine distemper virus and canine coronavirus are an important cause of mortality and morbidity in dogs worldwide. Prior to this study, no information was available concerning the incidence and prevalence of these viruses in Cape Verde archipelago. Results To provide information regarding the health status of the canine population in Vila do Maio, Maio Island, Cape Verde, 53 rectal swabs were collected from 53 stray dogs during 2010 and 93 rectal swabs and 88 blood samples were collected from 125 stray dogs in 2011. All rectal swabs (2010 n = 53; 2011 n = 93) were analysed for the presence of canine parvovirus, canine distemper virus and canine coronavirus nucleic acids by quantitative PCR methods. Specific antibodies against canine distemper virus and canine parvovirus were also assessed (2011 n = 88). From the 2010 sampling, 43.3% (23/53) were positive for canine parvovirus DNA, 11.3% (6/53) for canine distemper virus RNA and 1.9% (1/53) for canine coronavirus RNA. In 2011, the prevalence values for canine parvovirus and canine coronavirus were quite similar to those from the previous year, respectively 44.1% (41/93), and 1.1% (1/93), but canine distemper virus was not detected in any of the samples analysed (0%, 0/93). Antibodies against canine parvovirus were detected in 71.6% (63/88) blood samples and the seroprevalence found for canine distemper virus was 51.1% (45/88). Conclusions This study discloses the data obtained in a molecular and serological epidemiological surveillance carried out in urban populations of stray and domestic animals. Virus transmission and spreading occurs easily in large dog populations leading to high mortality rates particularly in unvaccinated susceptible animals. In addition, these animals can act as disease reservoirs for wild animal populations by occasional contact. Identification of susceptible wildlife of Maio Island is of upmost importance to evaluate the risk

  11. Diagenetic fate of organic contaminants on the Palos Verdes Shelf, California

    USGS Publications Warehouse

    Eganhouse, R.P.; Pontolillo, J.; Leiker, T.J.

    2000-01-01

    Municipal wastes discharged through deepwater submarine outfalls since 1937 have contaminated sediments of the Palos Verdes Shelf. A site approximately 6-8 km downcurrent from the outfall system was chosen for a study of the diagenetic fate of organic contaminants in the waste-impacted sediments. Concentrations of three classes of hydrophobic organic contaminants (DDT + metabolites, polychlorinated biphenyls (PCBs), and the long-chain alkylbenzenes) were determined in sediment cores collected at the study site in 1981 and 1992. Differences between the composition of effluent from the major source of DDT (Montrose Chemical) and that found in sediments suggests that parent DDT was transformed by hydrolytic dehydrochlorination during the earliest stages of diagenesis. As a result, p,p'-DDE is the dominant DDT metabolite found in shelf sediments, comprising 60-70% of ??DDT. The p,p-DDE/p,p'-DDMU concentration ratio decreases with increasing sub-bottom depth in sediment cores, indicating that reductive dechlorination of p,p'-DDE is occurring. Approximately 9-23% of the DDE inventory in the sediments may have been converted to DDMU since DDT discharges began ca. 1953. At most, this is less than half of the decline in p,p'-DDE inventory that has been observed at the study site for the period 1981-1995. Most of the observed decrease is attributable to remobilization by processes such as sediment mixing coupled to resuspension, contaminant desorption, and current advection. Existing field data suggest that the in situ rate of DDE transformation is 102-103 times slower than rates determined in recent laboratory microcosm experiments (Quensen, J.F., Mueller, S.A., Jain, M.K., Tiedje, J.M., 1998. Reductive dechlorination of DDE to DDMU in marine sediment microcosms. Science, 280, 722-724.). This explains why the DDT composition (i.e. o,p'-, p,p'-isomers of DDE, DDD, DDT) of sediments from this site have not changed significantly since at least 1972. Congener-specific PCB

  12. Age dependent variation of magnetic fabric on dike swarms from Maio Island (Cape Verde)

    NASA Astrophysics Data System (ADS)

    Moreira, Mário; Madeira, José; Mata, João.; Represas, Patrícia

    2010-05-01

    Maio is one of the oldest and most eroded islands of Cape Verde Archipelago. It comprises three major geological units: (1) an old raised sea-floor sequence of MORB covered by Jurassic(?)-Cretaceous deep marine sediments; (2) an intrusive 'Central Igneous Complex' (CIC), forming a dome-like structure in the older rocks; and (3) a sequence of initially submarine, then subaerial, extrusive volcanic formations and sediments. Based on the trend distribution of 290 dikes, we performed magnetic sampling on 26 basic and one carbonatite dikes. Anisotropy of magnetic susceptibility (AMS) was measured to infer geometries of magmatic flow. Dikes were sampled in both chilled margins were larger shear acting on particles embedded in the magmatic flow is expected. Sampling involved 11 dikes (N=195) intruding MORB pillows from the Upper Jurassic 'Batalha Formation' (Bt fm); 6 dikes (N=95) intruding the Lower Cretaceous 'Carquejo Formation' (Cq fm), and 10 dikes (N=129) intruding the submarine sequence of the Neogene 'Casas Velhas Formation' (CV fm). The studied hypabissal rocks are usually porphyritic, with phenocrysts of clinopyroxene and/or olivine set on an aphanitic groundmass. Dikes intruding CV fm trend N-S to NE-SW and plunge to SW. In Bt fm, dikes make ≈ 99% of the outcrops, span all directions and include frequent low dip sills. Dikes intruding Cq fm are shallow (mostly parallel to the limestone strata), dip 30o- 40o to the E, and trend N-S to NE-SW. Bulk susceptibility of the 26 basic dikes presents an average value of k = 47 ± 26 (×10-3) SI. The carbonatite dike intruding Bt fm has lower susceptibility: k = 4.6 ± 1.2 (×10-3) SI. More than 80% of the dikes show normal and triaxial magnetic fabric. Anisotropy is usually low, with P' < 1.08, but in CV fm dikes the anisotropy is higher and grows (up to P' ≈ 1.5) towards the centre of the volcano. Dominant magnetic fabric in CV fm is planar but in dikes from Cq fm and Bt fm it varies between oblate and prolate

  13. Status of vegetation cover after 25 years since the last wildfire (Río Verde, Spain)

    NASA Astrophysics Data System (ADS)

    Martinez-Murillo, Juan F.; Remond, Ricardo; Ruiz-Sinoga, José D.

    2016-04-01

    Climatic conditions play an important role in the post-fire vegetation recovery as well as other factors like topography, soil, and pre and post-fire land use (Shakesby, 2011; Robichaud et al., 2013). This study deals with the characterization of the vegetation cover status in an area affected by a wildfire 25 years ago. Namely, the objectives are to: i) compare the current and previous vegetation cover to wildfire; and ii) evaluate whether the current vegetation has recovered the previous cover to wildfire. The study area is mainly located in the Rio Verde watershed (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 8,156 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 1700 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. The Andalucía Regional Government wildfire historic records were used to select the burned area and its geographical limit. 1991 and 2013 land cover maps were obtained by means of object-oriented classifications. Also, NDVI index were calculated and mapped for both years in order to compare the status of vegetation cover. According to the results, the combination of remote sensing and GIS analysis let map the most recovered areas affected by the wildfire in 1991. The vegetation indexes indicated that

  14. The Patagonian Orocline: Paleomagnetic evidence of a large counter-clockwise rotation during the closure of the Rocas Verdes basin.

    NASA Astrophysics Data System (ADS)

    Poblete, Fernando; Roperch, Pierrick; Herve, Francisco; Ramirez, Cristobal; Arriagada, Cesar

    2014-05-01

    The southernmost Andes of Patagonia and Tierra del Fuego present a prominent arc-shaped structure, the Patagonian Orocline. Despite the fact that this major structure was already described by Alfred Wegener in his famous textbook in 1929, few paleomagnetic studies have been attempted to describe the rotations associated with the formation of the Patagonian Orocline. In this study we present a paleomagnetic and anisotropy of magnetic susceptibility (AMS) study from more than 130 sites obtained from the Ultima Esperanza region (NS structures at ~51°S) to Península Hardy, south of the Beagle Channel at ~55°S. 45 sites were sampled in early-cretaceous gabbros (gabbro complex), mid-cretaceous tonalites and granodiorites (Canal Beagle group) and Paleocene intrusive rocks (Seno Año Nuevo group) from the South Patagonian batholith, 4 sites from the late Jurassic Hardy formation, a volcanic succession outcropping in Hardy Peninsula and Stewart Island, 9 sites were drilled in the lower cretaceous sedimentary infill of the Rocas Verdes Basin, 3 sites from the Tortuga ophiolite, a quasi-oceanic crust related to the opening of the Rocas Verdes basin. 80 sites were sampled in Cretaceous to Miocene sedimentary rocks from the Magallanes fold and thrust belt and Magallanes Basin. Characteristic Remanent Magnetizations (ChRMs) obtained from the Rocas Verdes Basin tectonic province correspond to secondary magnetizations postdating the early phase of folding. Pyrrhotite is the main magnetic carrier in some of these sites. ChRMs from the South Patagonian Batholith correspond to a primary magnetization. These rocks record about 90° counterclockwise rotations south of the Beagle channel. Few sites from sediments of the Magallanes fold and thrust belt have stable ChRM. The available paleomagnetic results show that no rotation has occurred in the Provincia of Ultima Esperanza (51.5°S), at least, for the last 60 Ma. In the southern part of Provincia de Magallanes and Tierra del Fuego

  15. A clonal Plasmodium falciparum population in an isolated outbreak of malaria in the Republic of Cabo Verde.

    PubMed

    Arez, A P; Snounou, G; Pinto, J; Sousa, C A; Modiano, D; Ribeiro, H; Franco, A S; Alves, J; do Rosario, V E

    1999-04-01

    We present the first parasitological, molecular and longitudinal analysis of an isolated outbreak of malaria. This outbreak occurred on Santiago Island (Republic of Cabo Verde), a region where malaria is hypoendemic and controlled, and thus the population is considered non-immune. Blood samples were collected from the inhabitants over 1 month and during cross-sectional surveys in the following year. The presence and nature of the parasites was determined by PCR. Plasmodium falciparum was the only species detected. Genetic analysis revealed that the circulating parasites were genetically homogeneous, and probably clonal. Gametocytes were found throughout this period. Our data suggest that this represented a focal outbreak, resulting in the infection of at least 40% of the villagers with a clonal parasite line. Thus, P. falciparum infections can persist for at least 1 year in a substantial proportion (10%) of the hosts. Implications for malaria control and the interpretation of epidemiological data are discussed. PMID:10340324

  16. Relationships of scincid lizards (Mabuya spp; Reptilia: Scincidae) from the Cape Verde islands based on mitochondrial and nuclear DNA sequences.

    PubMed

    Brehm, A; Jesus, J; Pinheiro, M; Harris, D J

    2001-05-01

    Partial DNA sequences from two mitochondrial (mt) and one nuclear gene (cytochrome b, 12S rRNA, and C-mos) were used to estimate the phylogenetic relationships among the six extant species of skinks endemic to the Cape Verde Archipelago. The species form a monophyletic unit, indicating a single colonization of the islands, probably from West Africa. Mabuya vaillanti and M. delalandii are sister taxa, as indicated by morphological characters. Mabuya fogoensis and M. stangeri are closely related, but the former is probably paraphyletic. Mabuya spinalis and M. salensis are also probably paraphyletic. Within species, samples from separate islands always form monophyletic groups. Some colonization events can be hypothesized, which are in line with the age of the islands. C-mos variation is concordant with the topology derived from mtDNA. PMID:11341812

  17. Maps showing ground-water conditions in the upper Verde River area, Yavapai and Coconino counties, Arizona; 1978

    USGS Publications Warehouse

    Levings, Gary W.; Mann, Larry J.

    1980-01-01

    The upper Verde River area includes about 3,600 square miles in north-central Arizona. The area is underlain by a regional aquifer that consists of several formations. In places ground water also is present in the igneous rocks and basalt flows and in the alluvium along the channels and flood plains of the streams. Ground-water development has been slight; in 1978 about 8,000 acre-feet of ground water was withdrawn for domestic, public-supply, industrial, and irrigation uses. Information on the maps includes the principal geologic formation that furnishes water to wells and springs, depth to water, altitude of the water level, and chemical quality of the water. Scale 1:125,000. (USGS)

  18. Continental underthrusting and obduction during the Cretaceous closure of the Rocas Verdes rift basin, Cordillera Darwin, Patagonian Andes

    NASA Astrophysics Data System (ADS)

    Klepeis, Keith; Betka, Paul; Clarke, Geoffrey; Fanning, Mark; Hervé, Francisco; Rojas, Lisandro; Mpodozis, Constantino; Thomson, Stuart

    2010-06-01

    The Patagonian Andes record a period of Cretaceous-Neogene orogenesis that began with the compressional inversion of a Late Jurassic rift called the Rocas Verdes basin. Detrital zircon ages from sediment that filled the southern part of the basin provide a maximum depositional age of ˜148 Ma, suggesting that the basin opened approximately simultaneously along its length during the Late Jurassic. Structural data and U-Pb isotopic ages on zircon from granite plutons near the Beagle Channel (55°S) show that basin inversion involved two stages of shortening separated by tens of millions of years. An initial stage created a small (˜60 km wide) thrust wedge that placed the basaltic floor of the Rocas Verdes basin on top of adjacent continental crust prior to ˜86 Ma. Structures and metamorphic mineral assemblages preserved in an exhumed middle to lower crustal shear zone in Cordillera Darwin suggest that this obduction was accompanied by south directed subduction of the basaltic crust and underthrusting of continental crust to depths of ˜35 km beneath a coeval volcanic arc. A subsequent stage of out-of-sequence thrusting, culminating in the Paleogene, shortened basement and Upper Jurassic igneous rock in the internal part of the belt by at least ˜50 km, forming a bivergent thrust wedge. This latter period coincided with the exhumation of rocks in Cordillera Darwin and expansion of the fold-thrust belt into the Magallanes foreland basin. This orogen provides an important example of how orogenesis initiated and led to continental underthrusting and obduction of basaltic crust during closure of a quasi-oceanic rift basin.

  19. Analysis of malaria associated genetic traits in Cabo Verde, a melting pot of European and sub Saharan settlers.

    PubMed

    Alves, Joana; Machado, Patrícia; Silva, João; Gonçalves, Nilza; Ribeiro, Letícia; Faustino, Paula; do Rosário, Virgílio Estólio; Manco, Licínio; Gusmão, Leonor; Amorim, António; Arez, Ana Paula

    2010-01-15

    Malaria has occurred in the Cabo Verde archipelago with epidemic characteristics since its colonization. Nowadays, it occurs in Santiago Island alone and though prophylaxis is not recommended by the World Health Organization, studies have highlight the prospect of malaria becoming a serious public health problem as a result of the presence of antimalarial drug resistance associated with mutations in the parasite populations and underscore the need for tighter surveillance. Despite the presumptive weak immune status of the population, severe symptoms of malaria are not observed and many people present a subclinical course of the disease. No data on the prevalence of sickle-cell trait and red cell glucose-6-phosphate dehydrogenase deficiency (two classical genetic factors associated with resistance to severe malaria) were available for the Cabo Verde archipelago and, therefore, we studied the low morbidity from malaria in relation to the particular genetic characteristics of the human host population. We also included the analysis of the pyruvate kinase deficiency associated gene, reported as putatively associated with resistance to the disease. Allelic frequencies of the polymorphisms examined are closer to European than to African populations and no malaria selection signatures were found. No association was found between the analyzed human factors and infection but one result is of high interest: a linkage disequilibrium test revealed an association of distant loci in the PKLR gene and adjacent regions, only in non-infected individuals. This could mean a more conserved gene region selected in association to protection against the infection and/or the disease. PMID:19837619

  20. Tectonic implications of space-time patterns of Cenozoic volcanism in the Palo Verde Mountain volcanic field, southeastern California

    SciTech Connect

    Murray, K.S.

    1981-01-01

    Variations in Cenozoic volcanism in the western United States are believed to correlate closely with changes in tectonic setting. A transition in volcanic association from calc-alkaline to fundamentally basaltic volcanism and subsequent crustal extension, appears to have coincided temporally with the initial collision of the East Pacific Rise with the continental margin trench off western North America, between 28 and 25 Ma. The volcanic stratigraphy of the Palo Verde Mountain volcanic field is broadly similar to other volcanic centers in southeastern California and can be divided into tripartite regional stratigraphy. A basal sequence of andesitic to rhyolitic lava flows, plugs, domes, and extensive pyroclastic deposits rests unconformably on pre-Cenozoic basement rocks. The basal sequence is intruded by cogenetic Cenozoic plutonic rocks and overlain by basaltic to rhyolitic lava flows, dikes, and a second widespread assemblage of pyroclastic deposits, cumulatively referred to as the silicic sequence. The youngest volcanic rocks of the field include olivine basalt flows and breccia which occur at scattered localities in the Palo Verde Mountains. The age, stratigraphy, and chemistry of the intermediate and basaltic composition volcanic rocks broadly supports previously cited volcanic-tectonic models, if modified to incorporate modern plate reconstruction theory. This modification results in a southeast migration of the transition to basaltic volcanism to southeastern California occurring significantly later in time than the previously cited ages of transition. Moreover, this southeast migration of the volcanic transition is coincident with the inception of Basin and Range faulting and the initiation of movement on the San Andreas fault south of the Transverse Ranges, corresponding to the southward migration of the Pacific-Cocos Ridge.

  1. Relative paleointensity of the geomagnetic field over the last 4,500 years BP from sediment cores of Laguna Chaltel (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Gogorza, C. G.; Irurzun, M. A.; Sinito, A. M.; Aldana, M.; Fey, M.; Ohlendorf, C.; Zolitschka, B.

    2013-05-01

    One motivation to investigate the magnetism of rocks is to study the behaviour of Earth's magnetic field of the past. The magnetic field is a vector field, having both direction and intensity. A complete understanding of it requires the study of all vector properties. However, paleointensity determinations are much more difficult than directions alone. This is one reason why the majority of paleomagnetic studies is concerned only with the directional variability of the magnetic field. Four short gravity cores from Laguna Chaltel in Patagonia, Argentina (49° 57'S, 71° 06'W) have been used to estimate the regional geomagnetic paleointensity. Measurements of intensity and directions of Natural Remanent Magnetization (NRM), magnetic susceptibility (k), isothermal remanent magnetization (IRM), saturation isothermal remanent magnetization (SIRM), as well as back field and anhysteretic remanent magnetization at 100 mT (ARM100mT) were performed and associated parameters calculated (ARM100mT/k, SIRM/ ARM100mT). In order to identify the magnetic mineralogy of the samples, IRM curves of a group of pilot samples were decomposed applying a Direct Signal Analysis (DSA) (Aldana et al., 2011). Results indicate the presence of magnetite, with logB1/2=1.8 and a relative proportion of 80%. Two other magnetic phases are observed at lower and higher logB1/2 values, probably greigite and goethite, respectively. DSA also indicates that the relative proportion of these minerals is the same in all samples analyzed. Studies also show that the magnetic grain size varies between 1 and 8 μm and that their concentration is between 0.01 and 0.08%. This range of the studied parameters indicates that our samples are suitable for paleointensity studies. The remanent magnetization at 15 mT (NRM15mT) has been normalized using the anhysteretic remanent magnetization at 15 mT (ARM15 mT), the saturation of isothermal remanent magnetization at 15 mT (SIRM15mT) and low field magnetic susceptibility (k

  2. Core scanning procedures and first characterisation of the 106 m long lacustrine sediment record of Laguna Potrok Aike, Argentina (ICDP-project PASADO)

    NASA Astrophysics Data System (ADS)

    Ohlendorf, Christian; Enters, Dirk; Gebhardt, Catalina; Hahn, Annette; Kliem, Pierre; Zolitschka, Bernd; Pasado Science Team

    2010-05-01

    Drilling operations for the southernmost ICDP project dedicated to terrestrial paleoclimatic reconstruction, the "Potrok Aike Maar Lake Sediment Archive Drilling Project" (PASADO), were completed in late November 2008. In the maar lake Laguna Potrok Aike (52°S, 70°W; 116 m asl.; diameter: 3.5 km, water depth: 100 m) in southern Patagonia, Argentina in total 510 m of lacustrine sediments have been recoverd using the GLAD800 platform equipped with a CS-1500 drill rig. Quadruplicate and triplicate cores down to a maximum depth of 101.5 m below lake floor have been taken using mainly the hydraulic piston coring tool. Total core recovery was 94,4 % from two drillsites located 700 m apart from each other in the central profundal plane of the lake. In 2009 all cores from Site 2 (southern basin plane) and most cores from Site 1 (central basin plane) were opened, described, documented by digital high resolution photography and scanned with different non-destructive techniques. A 106.08 m long composite profile was constructed for Site 2 based on visual core correlation and was then subsampled completely in consecutive 2 cm thick intervalls. Core scanning was performed in 5 mm steps for all parameters and involved the following techniques: 1) color scanning with a handheld X-rite spectrometer, 2) magnetic susceptibility scanning with a Bartington MS2F-sensor, 3) XRF scanning and X-radiography with an ITRAX core scanner (COX analytical systems) and 4) p-wave velocity/transmission seismograms and gamma ray absorption with a modified Geotek MSCL tool. According to the preliminary age model, the sedimentary record from Laguna Potrok Aike reaches back to OIS 3 and exhibits contrasting lithologies downcore especially in the Pleistocene part of the record. Moreover, first estimates indicate that up to 50% of the record consist of redeposited sediments. To account for these pronounced downcore lithological changes it was necessary to adjust the XRF-scanning parameters (i.e. X

  3. Rock magnetic study and paleomagnetic reconstruction from the maar Lake Laguna Potrok Aike, southern Argentina: preliminary results from the PASADO-ICDP record

    NASA Astrophysics Data System (ADS)

    Lise-Pronovost, A.; St-Onge, G.; Gogorza, C. G.; Haberzettl, T.; PASADO Team

    2010-12-01

    In the framework of the International Continental scientific Drilling Program (ICDP), the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) team drilled Laguna Potrok Aike (52°S, 70°W) in southern Argentina during austral spring 2008. A composite sedimentary sequence of 106 meters from the center of the lake was recovered. Here we present a high-resolution rock magnetic study and paleomagnetic reconstruction for the uppermost 50 m of the PASADO-ICDP composite profile. The natural remanent magnetization (NRM), the anhysteretic and two isothermal remanent magnetizations (ARM, IRM and SIRM) were measured at 1 cm intervals using a 2G u-channel cryogenic magnetometer. Hysteresis properties were measured at ca. 50 cm intervals using a Princeton Measurements Corporation alternating gradient force magnetometer. Temperature dependence of magnetic susceptibility was measured from 50°C to 700°C using a Bartington furnace and susceptibility meter system for all core catcher samples and low field volumetric magnetic susceptibility (kLF) was measured at 1 cm intervals using a multi sensor core logger (MSCL). Preliminary results indicate that the magnetic assemblage of the uppermost 50 m is dominated by low coercivity minerals such as magnetite with grains ranging from pseudo single to multi domain (PSD to MD). The magnetic assemblage of the uppermost ca. 8 meters is characterized by magnetic grains fining upward, as indicated by grain size ratios (kARM/kLF, MDFARM/MDFIRM, ARM/SIRM) and the coercivity ratio Hcr/Hc. These results are consistent with the mid-Holocene lake level rise at Laguna Potrok Aike inferred from geochemical and elemental proxies. Beyond the currently available chronology (ca. 19 m; 16 000 cal BP) and down to 50 m, magnetic grains are generally coarser and rapidly deposited layers become more numerous, most likely because of stronger winds at the end of the last glacial period. Rapidly deposited layers such as turbidites and reworked tephra

  4. Insights from fumarole gas geochemistry on the recent volcanic unrest of Pico do Fogo, Cape Verde

    NASA Astrophysics Data System (ADS)

    Melián, Gladys V.; Dionis, Samara; Asensio-Ramos, María; Padilla, Germán; Fernandes, Paulo; Pérez, Nemesio M.; Sumino, Hirochika; Padrón, Eleazar; Hernández, Pedro A.; Silva, Sónia; Pereira, José Manuel; Semedo, Helio; Cabral, Jeremias

    2015-04-01

    Fogo is a volcanic island of the Cape Verde archipelago and host at its center the active stratovolcano Pico do Fogo (2829 m.a.s.l.). On November 23, 2014 a new volcanic eruption started at the southwestern flank of Pico do Fogo, after 19 years of the last eruptive event. Since 2007, regular sampling and analysis of fumarole gas discharges from a fumarole (F1) has been performed in a yearly basis to monitor the chemical and isotopic gas composition. From 2008, fumarole gas sampling was also performed in a second fumarole (F2). During the period of study, outlet temperature in F1 has ranged between 62 to 159°C, whereas the F2 has ranged between 295 and 344°C. For determination of major gas species, fumarolic gases were collected in evacuated flasks containing a 5N NaOH solution. In addition, condensed steam and non-condensable gases (dry gas) were sampled by flowing the fumarolic gases through a water-cooled condenser. The isotopic composition of He (3He/4He) was determined on dry gas samples at the GRC of Tokyo University. Water vapor is by far the most abundant component, as shown by a gas/steam molar ratio between 0.08 and 0.48, followed by CO2 (384,606 - 988,679 mmol/mol in the dry gas phase). The concentration of the other gases in the gas dry phase and expressed in mol/mol: Stotal varies from 3,411 to 606,054, N2 from 835 to 84,672, H2 from 45.6 to 68,439, CH4 from 0 to 61,785, Cl from 4.9 to 1,729, CO from 0 to 1,396 and He from 4.4 to 617. The presence of O2 in concentrations from 10.4 to 17,350 mol/mol reflects minor air contamination either during sampling or storage, or naturally in the sampled vents. Carbon isotopic composition of Pico do Fogo fumarolic CO2, expressed in d13C-CO2 vs. VPDB notation, varied from -4.62 to -4.06 ‰, whereas 3He/4He data, expressed as R/RA, ranged from 5.70 to 8.81. In the classical He-Ar-N2 triangular diagram, most of samples plot between the He, air and ASW end members, showing compositions variably contaminated by

  5. Co-variation in Magma Compositions, Effusion rates and Seismic Tremor During the 2014-15 Eruption of Fogo volcano, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Day, S. J.

    2015-12-01

    Magma compositions vary widely within many eruptions of ocean island volcanoes, particularly those in the Canaries and Cape Verde Islands. The 23 November 2014 to 7 February 2015 eruption of Fogo in the Cape Verde Islands was the first eruption in either the Canaries or the Cape Verdes to be monitored by multiple satellite instruments that measured infrared emissions of the eruption and so enabled continuous quantitative estimation of magma effusion rates and their variation through time. It is also the first eruption in the Cape Verdes for which seismic tremor intensity, indicative of magma ascent dynamics, was continuously recorded. Effusion rates were highest, peaking at about 20 m3/s, in the first five days of eruption but later asymptotic decay in effusion rate was interrupted around 9 and 16 December by pulses of increased effusion. Activity was mainly mildly explosive from December 31, accompanied by intensified seismic tremor. A final pulse of low-rate lava effusion occurred from 17 to 22 January. These data provide a new framework within which to relate compositional variations in the eruption to variations in magma ascent and effusion. We collected a suite of samples whose dates of emplacement have been determined from the date of incandescence of each sample site in high-resolution thermal infrared emissivity maps collected by satellite during the eruption. The samples are highly porphyritic and strongly alkaline in composition, as is typical of Fogo magmas. The first- (November 23/24) and last- (January) erupted magma batches show evidence for hybridization with more evolved magma batches, and the 9 and 16 December magma pulses may be distinct from the magma erupted during the main phase of the eruption. We present data on the samples that allow us to examine the hypothesis that the effusion rate variations were controlled by tapping of different parts of the magma reservoir or reservoirs during the eruption.

  6. Investigation of the application of HCMM thermal data to snow hydrology. [Salt-Verde watershed, Arizona and Kings River Basin, California

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. Analysis of HCMM digital thermal data for daytime passes over the Salt-Verde Watershed area on five dates show a gradual depletion of snow cover in the watershed (and in the Little Colorado Watershed to the north) from a maximum on February 9th to a nearly complete disappearance of the snow pack by April 15th. Temperature contours correspond closely with the snowline observed in the visible image.

  7. Vector competence of Aedes aegypti and Aedes vittatus (Diptera: Culicidae) from Senegal and Cape Verde archipelago for West African lineages of chikungunya virus.

    PubMed

    Diagne, Cheikh T; Faye, Oumar; Guerbois, Mathilde; Knight, Rachel; Diallo, Diawo; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Faye, Ousmane; Weaver, Scott C; Sall, Amadou A; Diallo, Mawlouth

    2014-09-01

    To assess the risk of emergence of chikungunya virus (CHIKV) in West Africa, vector competence of wild-type, urban, and non-urban Aedes aegypti and Ae. vittatus from Senegal and Cape Verde for CHIKV was investigated. Mosquitoes were fed orally with CHIKV isolates from mosquitoes (ArD30237), bats (CS13-288), and humans (HD180738). After 5, 10, and 15 days of incubation following an infectious blood meal, presence of CHIKV RNA was determined in bodies, legs/wings, and saliva using real-time reverse transcription-polymerase chain reaction. Aedes vittatus showed high susceptibility (50-100%) and early dissemination and transmission of all CHIKV strains tested. Aedes aegypti exhibited infection rates ranging from 0% to 50%. Aedes aegypti from Cape Verde and Kedougou, but not those from Dakar, showed the potential to transmit CHIKV in saliva. Analysis of biology and competence showed relatively high infective survival rates for Ae. vittatus and Ae. aegypti from Cape Verde, suggesting their efficient vector capacity in West Africa. PMID:25002293

  8. Radiogeochemical Properties and Cycling at the Caribbean National Forest El Verde Research Station and Surrounding Region on the Island of Puerto Rico

    NASA Astrophysics Data System (ADS)

    Ithier-Guzman, W.; Pyrtle, A. J.

    2007-12-01

    From 1964 through the early 1970's the Atomic Energy Commission conducted a series of experiments at The El Verde Research Station in Puerto Rico. Among these experiments included several involving the use of Cs-137 and other anthropogenic radionuclides. Radiological tests on the trees and vegetation were conducted in a small section of rainforest to study mineral cycling and metabolism. Studies on fauna and water movement were also conducted. In 2003 an investigation of long-term radiogeochemical cycling at the El Verde Research Station was launched. Results from radiogeochemical analysis of sediments and soils collected from El Verde Research Station, nearby streams, as well as the estuary of Coco Beach in the municipality of Rio Grande, Puerto Rico are presented. Cs-137 activities range from below detection limits to 0.4 Bq/g. Ancillary data obtained from grain size, X-ray diffraction, ICP-OES analyses are also discussed. Understanding the current environmental health of study region's ecosystem is vital, given the fact that this area serves as one of the largest sources of potable water for more than 13 municipalities of Puerto Rico.

  9. Magnetic parameters and their palaeoclimatic implications—the sediment record of the last 15 500 cal. BP from Laguna Potrok Aike (Argentina)

    NASA Astrophysics Data System (ADS)

    Irurzun, M. A.; Orgeira, M. J.; Gogorza, C. S. G.; Sinito, A. M.; Compagnucci, R.; Zolitschka, B.

    2014-08-01

    Lake sediments are excellent sources of palaeoenvironmental and palaeoclimatic information because they provide continuous and high-resolution records. South America is of particular interest because it is the only landmass that stretches southward into the Pacific and Atlantic Oceans towards Antarctica. The aim of this study is to explore the relationship of magnetic parameters with elemental and palaeobiological data of Laguna Potrok Aike to develop a model of lake-level changes and related hydrological and climatic fluctuations. Magnetic measurements were performed on subsamples from 15 500 cal. BP to the present, and associated rock magnetic parameters were calculated to infer magnetic mineralogy, concentration and grain size. According to the model, parameters dependent on magnetic concentration and grain size are directly related to lake-level changes. During dry periods, the remanent coercivity displays high values, whereas the proportion of magnetite is relatively low. Low percentages of greigite are observed, indicating that the water of the lake was stratified at least four times during the studied period, at approximately 10 300, 8900, 8500 and 8300 cal. BP. The preservation of greigite by inhibiting its complete transformation into pyrite is associated with a rapid burial that occurs with high sedimentation rates. Thermal stratification could be caused by a slight cooling in the area triggered by a weakening of the Westerlies and/or low activity of the sun, sum to the effect of a flood of melt water in the North Atlantic.

  10. The stratified microbial community at Laguna Figueroa, Baja California, Mexico: a possible model for prephanerozoic laminated microbial communities preserved in cherts.

    PubMed

    Stolz, J F; Margulis, L

    1984-01-01

    The microbial mat community of the evaporite flat at North Pond, Laguna Figueroa (Baja California, Mexico) was actively involved in the production of laminated sediments prior to 1978. Heavy rains in 1979 and 1980 flooded the mat with 1 and 3 meters of meteoric water respectively. The flooding deposited up to 10 cm of silicoclastic sediment over the Microcoleus-dominated mat and resulted in the cessation of laminated sediment deposition. In 1982, the surface had been recolonized by species of cyanobacteria (Spirulina, Oscillatoria) and purple photosynthetic bacteria (Chromatium, Thiocapsa). The silicoclastic sediments and residual evaporites, which overlaid the laminated sediment, had been reworked into an anaerobic, sulfide-rich mud and contained well preserved sheaths of filamentous and coccoid bacteria. The Swaziland Sequence in the Barberton mountain land (which includes the Onverwacht and Fig Tree Group as well as the Swartkoppie zone between them) contains laminated sediments and carbon-rich chert. Structurally preserved microfossils have been found in the smooth black chert but not in the laminae. We concur with others who suggested that the laminated sediments from the Swaziland Sequence were deposited by an active stratified microbial community. However, we propose that these organisms which were preserved were originally buried in the associated sulfide-rich muds and were subsequently silicified. PMID:11536585

  11. Lava Flow Hazard Assessment at Fogo Volcano, Cape Verde on the Base of Combined Terrestrial Laser Scanner and Photogrammetric Data

    NASA Astrophysics Data System (ADS)

    Richter, N.; Favalli, M.; De Zeeuw van Dalfsen, E.; Fornaciai, A.; Fernandes, R. M. S.; Perez, N. M.; Levy, J.; Victoria, S. S.; Walter, T. R.

    2015-12-01

    On November 23, 2014, after almost 20 years of dormancy, a major Hawaiian- to Strombolian-type eruption started at Fogo Volcano, Cape Verde. The eruption was very similar in style to previous eruptions and occurred from a vent at the western flank of the Pico do Fogo stratocone (2829 m). During this eruption, about 200 residential buildings and a significant portion of agricultural land were destroyed by lava flows. Also, the only road was blocked by lava, impeding evacuation and emergency response. As future eruptions could follow a similar pattern, and reconstruction of buildings and infrastructure has commenced, a detailed analysis of the pre- and post-eruptive topography, as well as a comprehensive lava flow hazard and risk assessment are needed. During a field campaign in January 2015, we collected Terrestrial Laser Scanner (TLS) and photogrammetric data. We construct a Digital Elevation Model (DEM) from almost 165 million TLS data points, covering 87.7 % of the new lava flows and most of the Chã das Caldeiras. We use the photogrammetric data and the Structure from Motion (SfM) method to cover the remaining 12.3 % of the affected area. By combining the TLS and SfM datasets, we construct an updated and high-quality DEM, including details on the lava flow morphology and the 2014/2015 eruptive vent. We estimate the total erupted lava volume and area by subtracting a pre-eruptive from the post-eruptive DEM. Based on this dataset, we are able to assess the lava flow hazard by simulating possible lava flow paths using the DOWNFLOW probabilistic code. We use a pre-eruptive DEM to reconstruct the flow paths of the 2014/2015 eruption. The new post-eruptive DEM is used to forecast possible future lava flow paths. We combine the hazard map with information on existing infrastructure (i.e. roads and settlements) in order to estimate the lava flow risk. As a final result we provide up-to-date lava flow hazard and risk maps for Fogo Volcano, Cape Verde.

  12. Investigating the potential for volcano flank instability triggered by recent dike intrusions at Fogo volcano, Cape Verde

    NASA Astrophysics Data System (ADS)

    Bagnardi, Marco; González, Pablo; Hooper, Andrew; Wright, Tim

    2015-04-01

    Gravitational flank-collapses at volcanoes are rare but catastrophic events that have rarely been witnessed by humans (e.g., Mount St. Helens in 1980). It has been proposed that gravitationally unstable volcanic flanks can be classified in two different types based on the flanks slope: volcanoes characterized by gentle slopes (Hawaiian-like) and that have very dynamic flanks exhibiting high rates of deformation and, conversely, steep-sided volcanoes (Macaronesian-like) showing minimal ground deformation. The two types of volcanoes could therefore reach the stable-state through different mechanisms and experience different mass-wasting processes. Numerous giant debris-avalanche deposits have been identified offshore the volcanoes of the Canary Islands and Cape Verde. Given the steep slopes of these volcanoes, the mass-wasting events may have occurred suddenly and with minimal precursory signals. Several mechanisms have been proposed as potential triggers and among these the intrusion of shallow dikes feeding fissure eruptions is one of the best candidates. In this work, we investigate this hypothesis in the light of new and revised results derived from the analysis of geodetic observations at Fogo volcano (Cape Verde). Fogo has erupted twice in the last 20 years (1995 and 2014-2015) and in both occasions the volcano erupted along fissures that seem to be fed by dykes intruding the shallow crust and the volcanic edifice. We re-process radar data from the ERS satellite to obtain state-of-the-art deformation maps spanning the 1995 eruption and revisit previously proposed models of the magmatic system. Our results indicate that both eruptions were fed by sub-vertical dikes, steeply dipping to the SE, and radiating from the Pico do Fogo volcanic cone to the SW. We also study the effect of such magmatic intrusions in terms of the stress regime that they generate and analyze whether the 1995 and 2014 intrusions could potentially destabilize the structures along which a

  13. Evolution of the Phreatomagmatic Cova de Paul Eruption, Santo Antao, Cape Verde Islands: Links Between Eruption Development and Crater Growth

    NASA Astrophysics Data System (ADS)

    Tarff, R.; Day, S. J.; Downes, H.; Seghedi, I.

    2013-12-01

    Episodes of phreatomagmatic explosive activity that excavate large deep craters occur at high-elevation vents on many oceanic island volcanoes. The water driving these explosions is sourced from freshwater aquifers within the volcanic edifices, whose location and other characteristics will influence crater growth and final geometry. Here we describe phreatomagmatic deposits from the single eruption that formed the large Cova de Paul crater on the island of Santo Antao, Cape Verde Islands. These deposits, emplaced after an initial Strombolian phase of activity, record wide fluctuations in the intensity of phreatomagmatic explosivity. The largest explosions produced low-temperature, indurated lithic-rich phreatomagmatic ignimbrites and surge deposits; these occur as isolated and often erosive-based units in more distal areas but are interbedded in proximal outcrops with airfall to mixed fall and flow breccia and ash beds containing varying proportions of lithic and juvenile clasts, pointing to a series of climactic explosions within an extended period of milder phreatomagmatic explosive activity. We find that whereas the lithic clasts in the mixed units can be matched with the varied rock units in the exposed crater walls, the ignimbrite and surge units also contain hydrothermally altered clasts that appear to have originated from deeper in the volcanic edifice. They imply that during the climactic explosions the crater was excavated to several hundred meters depth below the surface. The phreatomagmatic explosive phase of the CDPC eruption was initiated by shattering of the chilled margins of the eruptive conduit, which had formed during the early Strombolian activity. The remains of these chilled margins form a distinctive bed of large flow-banded angular sub-glassy juvenile clasts that separates the Strombolian deposits from the later phreatomagmatic deposits. At this point water inflow from pressurized aquifers into the conduit attained a critical coolant input

  14. Ventilation time scales of the North Atlantic subtropical cell revealed by coral radiocarbon from the Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Fernandez, Alvaro; Lapen, Thomas J.; Andreasen, Rasmus; Swart, Peter K.; White, Christopher D.; Rosenheim, Brad E.

    2015-07-01

    We present coral- and sclerosponge-based reconstructions of the 14C content in North Atlantic dissolved inorganic carbon (DIC) during the last ~100 years from the subtropical cells (STCs). These waters are sensitive to the dynamics of the shallow overturning meridional circulation that transports heat and water masses from the subtropics to the tropics. We use these records to investigate the circulation patterns of the off-equatorial upwelling regions of the STCs, which are not well understood. Coral and sclerosponge skeletons provide long time series of ocean DIC 14C content, a tracer of oceanic circulation, effectively extending the observational record back in time. Sclerosponge data from the Bahamas were used to extend the existing subtropical 14C time series to the 21st century. Coral 14C data from the Cape Verde Islands (1890-2002) captured the 14C signature of water brought to the surface in the off-equatorial regions of the STC present near the West African coast. We observe a unique postbomb trend at Cape Verde that is similar to the upwelling regions in the Pacific, and we interpret this trend as the result of the slow penetration of bomb 14C into the interior ocean as part of the STC circulation. Using a multibox mixing model we constrain the time history of bomb 14C in the eastern tropical Atlantic, and we estimate a 20 year time scale for ventilation of the thermocline in this area of the ocean. The similarity between the Atlantic and Pacific 14C-based records of upwelling suggests that both are caused by bomb 14C penetration rather than more complex explanations that invoke changes in thermocline depth (e.g., related to El Niño-Southern Oscillation variability) or changes in the strength of the subtropical cells. Our results offer constraints for models of tropical ocean circulation and anthropogenic CO2 uptake that attempt to reproduce the characteristics of the shallow wind-driven circulation in the Atlantic.

  15. Numerical analysis of the mobility of the Palos Verdes debris avalanche, California, and its implication for the generation of tsunamis

    USGS Publications Warehouse

    Locat, J.; Lee, H.J.; Locat, P.; Imran, J.

    2004-01-01

    Analysis of morphology, failure and post-failure stages of the Palos Verdes debris avalanche reveals that it may have triggered a significant tsunami wave. Our analysis of the failure itself indicates that the slope is stable under aseismic conditions but that a major earthquake (with a magnitude around 7) could have triggered the slide. A post-failure analysis, considering the debris avalanche as a bi-linear flow, shows that peak velocities of up to 45 m/s could have been reached and that the initial movement involved a mass of rock less than 10 km wide, 1 km long and about 50-80 m thick. Initial wave height estimates vary from 10 to 50 m. Tsunami waves propagating to the local shoreline would be significantly smaller. Such a range demonstrates our lack of proper knowledge of the transition from failure to post-failure behavior related to mass movements. Further investigations and analyses of terrestrial and submarine evidence are required for a proper hazard assessment related to tsunami generation in the Los Angeles area. ?? 2003 Elsevier B.V. All rights reserved.

  16. Kinetin increases chromium absorption, modulates its distribution, and changes the activity of catalase and ascorbate peroxidase in Mexican Palo Verde

    PubMed Central

    Zhao, Yong; Peralta-Videa, Jose R.; Lopez-Moreno, Martha L.; Ren, Minghua; Saupe, Geoffrey; Gardea-Torresdey, Jorge L

    2015-01-01

    This report shows, for the first time, the effectiveness of the phytohormone kinetin (KN) in increasing Cr translocation from roots to stems in Mexican Palo Verde. Fifteen-day-old seedlings, germinated in soil spiked with Cr(III) and (VI) at 60 and 10 mg kg−1, respectively, were watered every other day for 30 days with a KN solution at 250 μM. Samples were analyzed for catalase (CAT) and ascorbate peroxidase (APOX) activities, Cr concentration, and Cr distribution in tissues. Results showed that KN reduced CAT but increased APOX in the roots of Cr(VI)-treated plants. In the leaves, KN reduced both CAT and APOX in Cr(III) but not in Cr(VI)-treated plants. However, KN increased total Cr concentration in roots, stems, and leaves by 45%, 103%, and 72%, respectively, compared to Cr(III) alone. For Cr(VI), KN increased Cr concentrations in roots, stems, and leaves, respectively, by 53%, 129%, and 168%, compared to Cr(VI) alone. The electron probe microanalyzer results showed that Cr was mainly located at the cortex section in the root, and Cr distribution was essentially homogenous in stems. However, proven through X-ray images, Cr(VI)-treated roots and stems had more Cr accumulation than Cr(III) counterparts. KN increased the Cr translocation from roots to stems. PMID:21174467

  17. Offshore survey provides answers to coastal stability and potential offshore extensions of landslides into Abalone Cove, Palos Verdes peninsula, Calif

    SciTech Connect

    Dill, R.F. ); Slosson, J.E. )

    1993-04-01

    The configuration and stability of the present coast line near Abalone Cove, on the south side of Palos Verdes Peninsula, California is related to the geology, oceanographic conditions, and recent and ancient landslide activity. This case study utilizes offshore high resolution seismic profiles, side-scan sonar, diving, and coring, to relate marine geology to the stability of a coastal region with known active landslides utilizing a desk top computer and off-the-shelf software. Electronic navigation provided precise positioning that when applied to computer generated charts permitted correlation of survey data needed to define the offshore geology and sea floor sediment patterns. A mackintosh desk-top computer and commercially available off-the-shelf software provided the analytical tools for constructing a base chart and a means to superimpose template overlays of topography, isopachs or sediment thickness, bottom roughness and sediment distribution patterns. This composite map of offshore geology and oceanography was then related to an extensive engineering and geological land study of the coastal zone forming Abalone Cove, an area of active landslides. Vibrocoring provided ground sediment data for high resolution seismic traverses. This paper details the systems used, present findings relative to potential landslide movements, coastal erosion and discuss how conclusions were reached to determine whether or not onshore landslide failures extend offshore.

  18. Efficacy of CC traps and seasonal activity of adult Bemisia argentifolii (Homoptera: Aleyrodidae) in Imperial and Palo Verde Valleys, California.

    PubMed

    Chu, C C; Henneberry, T J; Natwick, E T; Ritter, D; Birdsall, S L

    2001-02-01

    Adult whitefly Bemisia argentifolii Bellows & Perring trap (CC trap) catches were compared with suction type trap catches. CC trap catches were significantly correlated to the suction trap catches. Higher numbers of B. argentifolii adults were caught in CC traps oriented toward an untreated, B. argentifolii-infested, cotton field as compared with traps oriented toward Bermuda grass fields, farm roads, or fallow areas. CC trap catches at five heights above ground (from 0 to 120 cm) were significantly related to each other in choice and no-choice studies. CC trap catches were low in the Imperial and Palo Verde Valleys from late October to early June each of 1996, 1997, and 1998. Trap catches increased with increasing seasonal air temperatures and host availability. Trap catches were adversely affected by wind and rain. Abrupt trap catch increases of 40- to 50-fold for 1-2 d in late June to early July followed by abrupt decreases in adult catches suggest migrating activity of adults from other nearby crop sources. PMID:11233132

  19. Detection of residual organochlorine and organophosphorus pesticides in agricultural soil in Rio Verde region of San Luis Potosi, Mexico.

    PubMed

    Velasco, Antonio; Hernández, Sergio; Ramírez, Martha; Ortíz, Irmene

    2014-01-01

    Organochlorine pesticides were intensively used in Mexico from 1950 until their ban and restriction in 1991. However, the presence of these compounds is commonly reported in many regions of the country. The aim of the present study was to identify and quantify residual organochlorine and organophosphorus pesticides in agricultural soil in Rio Verde region, San Luis Potosi state, which has been identified as possibly polluted by pesticides. Composed samples from 24 zones covering an area of approximately 5,440 ha were analyzed. The most frequently found pesticides were p,p'-DDT followed by ,p,p'-DDE, heptachlor, endosulfan and γ-HCH whose frequency rates were 100, 91, 83 and 54%, respectively. The concentration of p,p'-DDT in the crops grown in these soils was in the following order: chili > maize > tomato > alfalfa. The results obtained in this study show that p,p'-DDT values are lower or similar to those found in other agricultural regions of Mexico. Methyl and ethyl parathion were the most frequent organophosphate pesticide detected in 100% and 62.5% of the samples with average concentrations of 25.20 and 47.48 μg kg(-1), respectively. More research is needed to establish the background levels of pesticides in agricultural soils and their potential ecological and human health effects in this region. PMID:24813984

  20. Improving recombinant protein production in the Chlamydomonas reinhardtii chloroplast using vivid Verde Fluorescent Protein as a reporter.

    PubMed

    Braun-Galleani, Stephanie; Baganz, Frank; Purton, Saul

    2015-08-01

    Microalgae have potential as platforms for the synthesis of high-value recombinant proteins due to their many beneficial attributes including ease of cultivation, lack of pathogenic agents, and low-cost downstream processing. However, current recombinant protein levels are low compared to other microbial platforms and stable insertion of transgenes is available in only a few microalgal species. We have explored different strategies aimed at increasing growth rate and recombinant protein production in the Chlamydomonas reinhardtii chloroplast. A novel fluorescent protein (vivid Verde Fluorescent Protein, VFP) was expressed under the control of the native atpA promoter/5'UTR element. VFP levels were detected by western blotting, with increased protein levels observed when co-expressed with a gene encoding the Escherichia coli Spy chaperone. We used these transformant lines to study the effect of temperature, light and media on recombinant protein production and cell growth. VFP levels and fluorescence, assessed by flow cytometry, allowed a determination of improved cultivation conditions as 30°C under mixotrophic mode. These conditions were tested for the accumulation of an antimicrobial endolysin (Cpl-1) of potential commercial interest, observing that the outcome obtained for VFP could not be easily replicated for Cpl-1. This study suggests that recombinant protein expression is product-specific and needs to be optimized individually. PMID:26098300

  1. 3D-Reconstruction of recent volcanic activity from ROV-video, Charles Darwin Seamounts, Cape Verdes

    NASA Astrophysics Data System (ADS)

    Kwasnitschka, T.; Hansteen, T. H.; Kutterolf, S.; Freundt, A.; Devey, C. W.

    2011-12-01

    As well as providing well-localized samples, Remotely Operated Vehicles (ROVs) produce huge quantities of visual data whose potential for geological data mining has seldom if ever been fully realized. We present a new workflow to derive essential results of field geology such as quantitative stratigraphy and tectonic surveying from ROV-based photo and video material. We demonstrate the procedure on the Charles Darwin Seamounts, a field of small hot spot volcanoes recently identified at a depth of ca. 3500m southwest of the island of Santo Antao in the Cape Verdes. The Charles Darwin Seamounts feature a wide spectrum of volcanic edifices with forms suggestive of scoria cones, lava domes, tuff rings and maar-type depressions, all of comparable dimensions. These forms, coupled with the highly fragmented volcaniclastic samples recovered by dredging, motivated surveying parts of some edifices down to centimeter scale. ROV-based surveys yielded volcaniclastic samples of key structures linked by extensive coverage of stereoscopic photographs and high-resolution video. Based upon the latter, we present our workflow to derive three-dimensional models of outcrops from a single-camera video sequence, allowing quantitative measurements of fault orientation, bedding structure, grain size distribution and photo mosaicking within a geo-referenced framework. With this information we can identify episodes of repetitive eruptive activity at individual volcanic centers and see changes in eruptive style over time, which, despite their proximity to each other, is highly variable.

  2. Improving recombinant protein production in the Chlamydomonas reinhardtii chloroplast using vivid Verde Fluorescent Protein as a reporter

    PubMed Central

    Baganz, Frank; Purton, Saul

    2015-01-01

    Abstract Microalgae have potential as platforms for the synthesis of high‐value recombinant proteins due to their many beneficial attributes including ease of cultivation, lack of pathogenic agents, and low‐cost downstream processing. However, current recombinant protein levels are low compared to other microbial platforms and stable insertion of transgenes is available in only a few microalgal species. We have explored different strategies aimed at increasing growth rate and recombinant protein production in the Chlamydomonas reinhardtii chloroplast. A novel fluorescent protein (vivid Verde Fluorescent Protein, VFP) was expressed under the control of the native atpA promoter/5'UTR element. VFP levels were detected by western blotting, with increased protein levels observed when co‐expressed with a gene encoding the Escherichia coli Spy chaperone. We used these transformant lines to study the effect of temperature, light and media on recombinant protein production and cell growth. VFP levels and fluorescence, assessed by flow cytometry, allowed a determination of improved cultivation conditions as 30°C under mixotrophic mode. These conditions were tested for the accumulation of an antimicrobial endolysin (Cpl‐1) of potential commercial interest, observing that the outcome obtained for VFP could not be easily replicated for Cpl‐1. This study suggests that recombinant protein expression is product‐specific and needs to be optimized individually. PMID:26098300

  3. Laguna Potrok Aike, Argentina: the first non-tropical environmental record in South America extending far beyond the Late-Glacial - a progress report

    NASA Astrophysics Data System (ADS)

    Zolitschka, B.; Anselmetti, F.; Ariztegui, D.; Corbella, H.; Francus, P.; Gebhardt, C.; Lücke, A.; Ohlendorf, C.; Schäbitz, F.; Pasado Science Team

    2009-04-01

    Within the framework of the ICDP-funded "Potrok Aike maar lake sediment archive drilling project" (PASADO) an international team of scientists carried out interdisciplinary research at the unique mid-Pleistocene (770 ka) maar lake of Laguna Potrok Aike in southern Patagonia (Province of Santa Cruz, Argentina). This lake is very sensitive to variations in southern hemispheric wind and pressure systems and thus holds a unique and continuous lacustrine record of climatic and ecological variability of global significance. Moreover, Southern Patagonia with its many active volcanoes is an ideal location to better understand the regional history of volcanism. These are two challenging geo-scientific themes that need to be tackled, especially as both of them have an increasing socio-economic relevance. Three months of drilling activities that finished last November 2008 were carried out by DOSECC from the drilling platform R/V "Kerry Kelts". More than 500 m of lacustrine sediments were recovered. This sedimentary archive will provide (1) new insights into the processes of regional back arc volcanism within the Pali Aike Volcanic Field itself as well as the more distant explosive volcanism of the Andean mountain chains; and, (2) high-resolution (decadal) quantitative climate and environmental reconstructions supported by multiple dating and stratigraphic correlations. Marine - ice core - terrestrial linkages will be emphasized as well as the incorporation of results from global climate modelling simulations for the last ca. 100 ka. The two drilled sites in the central deep basin of Laguna Potrok Aike have been selected based on four seismic surveys carried out between 2003 and 2005. Sediments were recovered at both drilled sites down to a subbottom depth of slightly more than 100 m using the GLAD800 drill rig with the hydraulic piston corer tool (HPC) at water depths varying between 95 and 100 m. The total core recovery is 94%. On-site core logging with the multi sensor

  4. Changements climatiques et variations du champ magnetique terrestre dans le sud de la Patagonie (Argentine) depuis 51 200 ans reconstitues a partir des proprietes magnetiques des sediments du lac Laguna Potrok Aike

    NASA Astrophysics Data System (ADS)

    Lise-Pronovost, Agathe

    Rock magnetism is influenced by climate and by the Earth's magnetic field. The goal of this thesis is to use the rock magnetic properties of the long sedimentary sequence from the lake Laguna Potrok Aike (106 m, 51200 cal BP) to derive paleomagnetic and paleoclimatic records in a key area of the Southern Hemisphere that is poorly documented. Laguna Potrok Aike (52°S, 70°W) is located in southeastern Patagonia (Argentina) in the path of the strong Southern Hemisphere westerly winds and in the source area of the dust deposited in Antarctica during Glacial periods. The lake geographical location is therefore ideal to reconstruct past changes in aeolian activity and climate changes in Patagonia. It is also a key location to reconstruct past changes of the geomagnetic field because the Southern Hemisphere is significantly under-documented relative to the Northern Hemisphere. In addition, the proximity of the South Atlantic Anomaly (SAA) as well as the Southern Hemisphere high flux lobes could allow identifying differences in the paleomagnetic field evolution in southern South America relative to the much more documented Northern Hemisphere. For his strong potential to provide high-resolution climatic, aeolian and paleomagnetic records beyond the last climatic transition, the maar lake Laguna Potrok Aike was drilled in the framework of the International scientific Continental Drilling Program (ICDP) for the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). In this thesis, high-resolution rock-magnetic and physical properties are used in order to reconstruct paleoclimate and paleomagnetic records from the southernmost part of South America. In the first chapter, the full-vector paleomagnetic record (inclination, declination and relative paleointensity) derived from the sediments of Laguna Potrok Aike. A grain size influence on the relative paleointensity record (NRM/ARM) was corrected using the median destructive field of the natural remanent

  5. Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 2. Unit RL-10 boiler condition assessment report. Export trade information

    SciTech Connect

    Not Available

    1991-03-28

    The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the second of three volumes and it includes the following section: (1) Condition Assessment of Unit RL-10 Boiler.

  6. Rock-magnetic proxies of wind intensity and dust since 51,200 cal BP from lacustrine sediments of Laguna Potrok Aike, southeastern Patagonia

    NASA Astrophysics Data System (ADS)

    Lisé-Pronovost, Agathe; St-Onge, Guillaume; Gogorza, Claudia; Haberzettl, Torsten; Jouve, Guillaume; Francus, Pierre; Ohlendorf, Christian; Gebhardt, Catalina; Zolitschka, Bernd

    2015-02-01

    The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Located in the path of the Southern Hemisphere westerly winds and in the source region of dust deposited in Antarctica during Glacial periods, southern Patagonia is a vantage point to reconstruct past changes in aeolian activity. Here we use high-resolution rock-magnetic and physical grain size data from site 2 of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) in order to develop magnetic proxies of dust and wind intensity at 52°S since 51,200 cal BP. Rock-magnetic analysis indicates the magnetic mineral assemblage is dominated by detrital magnetite. Based on the estimated flux of magnetite to the lake and comparison with distal dust records from the Southern Ocean and Antarctica, kLF is interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale, when ferrimagnetic grain size and coercivity influence are minimal. Comparison to physical grain-size data indicates that the median destructive field of isothermal remanent magnetization (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension. Comparison with wind-intensity proxies from the Southern Hemisphere during the last Glacial period and with regional records from Patagonia since the last deglaciation including marine, lacustrine and peat bog sediments as well as speleothems reveals similar variability with MDFIRM up to the centennial time scale. MDFIRM is interpreted as a wind-intensity proxy independent of moisture changes for southeastern Patagonia, with stronger winds capable of transporting coarser magnetite bearing silts to the lake.

  7. Revealing the eruptive dynamics of post-glacial effusive volcanism in the western part of Laguna del Maule Volcanic Field: Insights into a complex magmatic system

    NASA Astrophysics Data System (ADS)

    Cáceres, F.; Castruccio, A.; Parada, M. Á.

    2015-12-01

    In this study we analyzed six Quaternary lava flows and one lava dome from Laguna del Maule Volcanic Field, in the Chilean Andes, in order to create a volcano-petrological eruptive model to get ideas about pre- and syn-eruptive stages, the main factors that control the broad distribution of vents and the architecture of magma reservoir. We estimated eruptive parameters such as effusion rates and erupted volumes, extrinsic and intrinsic lava flows emplacement controlling factors, magma ascent rates and pre-eruptive thermodynamics conditions to determine different stages in magma evolution from magma reservoir to emplacement of lava at surface. The analyzed lavas have andesitic-to-rhyolitic compositions, blocky morphology with volumes about a few cubic kilometers, thicknesses up to 140 m, maximum widths of 5 km and maximum lengths of 10 km. Modeling of the advance of these flows gives effusion rates of 10-1-102 m3s-1 and eruptions of a few months to years. Petrologic studies which include quantitative textural analyses and mineral and glass compositions, reveal similar provenance and crystalizing temperatures of similar minerals, coupled with similar pressures, H2O content and oxygen fugacity by similar lava composition, meanwhile individual chamber size estimations show an overlap sharing volume in near chambers indicating the equivalent provenance. Our main results about dynamics of lava flows suggest a crustal yield strength control in the emplacement over the internal viscosity of the flow for each lava. On the other hand, non-rhyolitic units appear to come from chambers located in similar depths and with coinciding volumes which indicate that the eruptions were triggered by the injection of different magma batches into a crystal-rich magma reservoir that could be divided into many sub-compartments which could explain the broad distribution of the vents. In addition, rhyolitic units also show similar thermodynamics conditions and coming from equivalent chambers.

  8. A 22,000 14C year BP sediment and pollen record of climate change from Laguna Miscanti (23°S), northern Chile

    NASA Astrophysics Data System (ADS)

    Grosjean, M.; van Leeuwen, J. F. N.; van der Knaap, W. O.; Geyh, M. A.; Ammann, B.; Tanner, W.; Messerli, B.; Núñez, L. A.; Valero-Garcés, B. L.; Veit, H.

    2001-02-01

    Lake sediments and pollen, spores and algae from the high-elevation endorheic Laguna Miscanti (22°45'S, 67°45'W, 4140 m a.s.l., 13.5 km 2 water surface, 10 m deep) in the Atacama Desert of northern Chile provide information about abrupt and high amplitude changes in effective moisture. Although the lack of terrestrial organic macrofossils and the presence of a significant 14C reservoir effect make radiocarbon dating of lake sediments very difficult, we propose the following palaeoenvironmental history. An initial shallow freshwater lake (ca. 22,000 14C years BP) disappeared during the extremely dry conditions of the Last Glacial Maximum (LGM; 18,000 14C years BP). That section is devoid of pollen. The late-glacial lake transgression started around 12,000 14C years BP, peaked in two phases between ca. 11,000 and <9000 14C years BP, and terminated around 8000 14C years BP. Effective moisture increased more than three times compared to modern conditions (˜200 mm precipitation), and a relatively dense terrestrial vegetation was established. Very shallow hypersaline lacustrine conditions prevailed during the mid-Holocene until ca. 3600 14C years BP. However, numerous drying and wetting cycles suggest frequent changes in moisture, maybe even individual storms during the mid-Holocene. After several humid spells, modern conditions were reached at ca. 3000 14C years BP. Comparison between limnogeological data and pollen of terrestrial plants suggest century-scale response lags. Relatively constant concentrations of long-distance transported pollen from lowlands east of the Andes suggest similar atmospheric circulation patterns (mainly tropical summer rainfall) throughout the entire period of time. These findings compare favorably with other regional paleoenvironmental data.

  9. Haematozoans from deep water fishes trawled off the Cape Verde Islands and over the Porcupine Seabight, with a revision of species within the genus Desseria (Adeleorina: Haemogregarinidae).

    PubMed

    Davies, Angela J; Hosein, Shazia; Merrett, Nigel R

    2012-02-01

    Archived blood smears from 32 of 113 fishes in 18 families and 12 orders, trawled from deep North Atlantic waters off the Cape Verde Islands in 1999 and over the Porcupine Seabight in 2001 were found to harbour haematozoans. These included four species of haemogregarines (Adeleorina, Haemogregarinidae) and a species of trypanosome (Trypanosomatina, Trypanosomatidae) located in Porcupine Seabight fishes. Also present were Haemohormidium-like structures of uncertain status found in samples from this location and from the Cape Verde Islands. Although material was limited, two of the haemogregarines were provisionally named Desseria harriottae sp. n. from Harriotta raleighana Goode et Bean (Chimaeriformes, Rhinochimaeridae), and Haemogregarina bathysauri sp. n. from Bathysaurus ferox Günther (Aulopiformes, Bathysauridae). The two remaining haemogregarines were identified as Desseria marshalllairdi (Khan, Threlfall et Whitty, 1992) from Halosauropsis macrochir (Günther) (Notacanthiformes, Halosauridae), and Haemogregarina michaeljohnstoni (Davies et Merrett, 2000) from Cataetyx laticeps Koefoed (Ophidiformes, Bythitidae). The name H. michaeljohnstoni was proposed to replace Haemogregarinajohnstoni Davies et Merrett, 2000 from C. laticeps and to avoid confusion with Hepatozoon johnstoni (Mackerras, 1961) Smith, 1996 from varanid lizards, originally named Haemogregarina johnstoni Mackerras, 1961. The trypanosome formed a mixed parasitaemia with D. harriottae in H. raleighana and was provisionally named Trypanosoma harriottae sp. n. No blood parasites had been described previously from cartilaginous fishes of the Holocephali, making the finds in H. raleighana unique. Haemohormidium-like structures were located in erythrocytes in one fish, Coryphaenoides armatus (Hector), among the Cape Verde Islands samples and in 12 species of fishes from the Porcupine Seabight; all these hosts were bony fishes. Finally, the haemogregarine species listed in the genus Desseria Siddall

  10. 78 FR 7819 - Request to Amend a License to Import

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... products source, special from the Laguna nuclear, and/or Verde Nuclear Power byproduct materials Plant... of mixed resulting will fission products and/ either be returned or corrosion directly to Laguna... Manganese-54. processor for further volume reduction processing and return to ETI for export back to...

  11. Urban Planning and Health Inequities: Looking in a Small-Scale in a City of Cape Verde

    PubMed Central

    Gonçalves, Luzia; Alves, Daniela; Simões, Rui; Delgado, António Pedro; Correia, Artur; Cabral, Jorge; Lapão, Luís Velez; Craveiro, Isabel

    2015-01-01

    Background The lack of high-quality data to support evidence-based policies continues to be a concern in African cities, which present marked social, economic and cultural disparities that may differently impact the health of the groups living in different urban contexts. This study explores three urban units—formal, transition and informal—of the capital of Cape Verde, in terms of overweight/obesity, cardiometabolic risk, physical activity and other aspects related to the urban environment. Methods Quantitative and qualitative research methods were used in this intra-urban study. A proportional stratified random sample (n = 1912 adults), based on geographical coordinates of private households, was selected to apply the UPHI-STAT questionnaire. In a second stage (n = 599), local nutritionists collected anthropometric measurements (e.g., height, waist circumference) and body composition by bioelectric impedance (e.g., body weight, body fat, muscle mass). In a third stage, pedometers were used to count study participants’ steps on working and non-working days for one week (n = 118). After a preliminary statistical analysis, a qualitative study was developed to complement the quantitative approach. Generalized linear models, among others, were used in the multivariate analysis. Results Insecurity was the main concern among survey respondents in the three units, notwithstanding with significant differences (p < 0.001) among units. About three-quarters (76.6%) of the participants of the informal unit emphasised the need for more security. The formal unit presents an older age structure (61.3% above 40 years old) and the transition unit a younger age structure (only 30.5% above 40 years old). Some health-related variables were analysed in each unit, revealing an excess of chronic conditions reported by inhabitants of informal unit, compared with the formal unit despite the informal unit’s younger age profile. The self-reported hypertension varied significantly

  12. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean

    USGS Publications Warehouse

    Garrison, Virginia H.; Majewski, Michael S.; Foreman, William T.; Genualdi, Susan A.; Mohammed, Azad; Massey Simonich, Stacy L.

    2014-01-01

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9–126 ng/m3 (mean = 25 ± 34) at source and 0.05–0.71 ng/m3 (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1–3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses.

  13. Acoustic profiles and images of the Palos Verdes Margin: Implications concerning deposition from the White's Point outfall

    SciTech Connect

    Hampton, M A.; Karl, H; Murray, Christopher J. )

    2001-12-01

    Subbottom profiles and sidescan-sonar images collected on and around the Palos Verdes shelf show a surficial deposit interpreted to contain effluent from the White's Point diffusers, as well as showing several geologic features that affect the deposit's distribution. The effluent-affected deposit is visible in high-resolution subbottom profiles on the shelf and the adjacent San Pedro basin slope to water depths of 170 m. It has a maximum thickness of 75 cm and was mapped acoustically over an area of 10.8 km{sup 2}, which encompasses a volume of about 3.2 million m{sup 3}. The deposit's basal reflector is acoustically distinct over most of the mapped area, implying that the deposit has not been extensively mixed across its base, perhaps being relatively free of reworking since its initial deposition. Nearshore, the basal reflector is weak and fades away toward land, which could result from syndepositional intermixing of coarse native sediment (particularly from the Portuguese Bend landslide) with effluent in the high-energy nearshore zone, or postdepositionally by physical (wave) or biological mixing across the interface. The geometry of the deposit implies that effluent is dispersed primarily in a northwesterly and seaward direction from the diffusers. Dispersal across the shelf break is in some places strongly affected by topography, particularly by submarine canyons. The deposit overlies stratified and unstratified Quaternary sediment, up to 30 m thick, that in turn overlies the irregular erosional surface of deformed Miocene bedrock that crops out in places on the shelf and upper basin slope. The effluent-affected deposit rests on potentially unstable landslide deposits on the San Pedro basin slope. The acoustic profiles and side-scan images show evidence for active and inactive vents, probably of hot water and gas, some of which are within the boundary of the effluent-affected sediment deposit and could disrupt it if seepage occurs.

  14. Acoustic profiles and images of the Palos Verdes margin: Implications concerning deposition from the White's Point outfall

    USGS Publications Warehouse

    Hampton, M.A.; Karl, Herman A.; Murray, C.J.

    2002-01-01

    Subbottom profiles and sidescan-sonar images collected on and around the Palos Verdes Shelf show a surficial deposit interpreted to contain effluent from the White's Point diffusers, as well as showing several geologic features that affect the deposit's distribution. The effluent-affected deposit is visible in high-resolution subbottom profiles on the shelf and the adjacent San Pedro basin slope to water depths of 170 m. It has a maximum thickness of 75 cm and was mapped acoustically over an area of 10.8 km2, which encompasses a volume of about 3.2 million m3. The deposit's basal reflector is acoustically distinct over most of the mapped area. implying that the deposit has not been extensively mixed across its base, perhaps being relatively free of reworking since its initial deposition. Nearshore, the basal reflector is weak and fades away toward land, which could result from syndepositional intermixing of coarse native sediment (particularly from the Portuguese Bend landslide) with effluent in the high-energy nearshore zone, or postdepositionally by physical (wave) or biological mixing across the interface. The geometry of the deposit implies that effluent is dispersed primarily in a northwesterly and seaward direction from the diffusers. Dispersal across the shelf break is in some places strongly affected by topography, particularly by submarine canyons. The deposit overlies stratified and unstratified Quaternary sediment, up to 30m thick, that in turn overlies the irregular erosional surface of deformed Miocene bedrock that crops out in places on the shelf and upper basin slope. The effluent-affected deposit rests on potentially unstable landslide deposits on the San Pedro basin slope. The acoustic profiles and side-scan images show evidence for active and inactive vents, probably of hot water and gas, some of which are within the boundary of the effluent-affected sediment deposit and could disrupt it if seepage occurs. ?? 2002 Elsevier Science Ltd. All rights

  15. Benefits and Challenges of Scaling Up Expansion of Marine Protected Area Networks in the Verde Island Passage, Central Philippines.

    PubMed

    Horigue, Vera; Pressey, Robert L; Mills, Morena; Brotánková, Jana; Cabral, Reniel; Andréfouët, Serge

    2015-01-01

    Locally-established marine protected areas (MPAs) have been proven to achieve local-scale fisheries and conservation objectives. However, since many of these MPAs were not designed to form ecologically-connected networks, their contributions to broader-scale goals such as complementarity and connectivity can be limited. In contrast, integrated networks of MPAs designed with systematic conservation planning are assumed to be more effective--ecologically, socially, and economically--than collections of locally-established MPAs. There is, however, little empirical evidence that clearly demonstrates the supposed advantages of systematic MPA networks. A key reason is the poor record of implementation of systematic plans attributable to lack of local buy-in. An intermediate scenario for the expansion of MPAs is scaling up of local decisions, whereby locally-driven MPA initiatives are coordinated through collaborative partnerships among local governments and their communities. Coordination has the potential to extend the benefits of individual MPAs and perhaps to approach the potential benefits offered by systematic MPA networks. We evaluated the benefits of scaling up local MPAs to form networks by simulating seven expansion scenarios for MPAs in the Verde Island Passage, central Philippines. The scenarios were: uncoordinated community-based establishment of MPAs; two scenarios reflecting different levels of coordinated MPA expansion through collaborative partnerships; and four scenarios guided by systematic conservation planning with different contexts for governance. For each scenario, we measured benefits through time in terms of achievement of objectives for representation of marine habitats. We found that: in any governance context, systematic networks were more efficient than non-systematic ones; systematic networks were more efficient in broader governance contexts; and, contrary to expectations but with caveats, the uncoordinated scenario was slightly more

  16. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean.

    PubMed

    Garrison, V H; Majewski, M S; Foreman, W T; Genualdi, S A; Mohammed, A; Massey Simonich, S L

    2014-01-15

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9-126 ng/m(3) (mean = 25 ± 34) at source and 0.05-0.71 ng/m(3) (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1-3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses. PMID:24055669

  17. DNA barcodes successfully identified Macaronesian Lotus (Leguminosae) species within early diverged lineages of Cape Verde and mainland Africa.

    PubMed

    Ojeda, Dario I; Santos-Guerra, Arnoldo; Oliva-Tejera, Felicia; Jaen-Molina, Ruth; Caujapé-Castells, Juli; Marrero-Rodríguez, Aguedo; Cronk, Quentin

    2014-01-01

    Plant DNA barcoding currently relies on the application of a two-locus combination, matK + rbcL. Despite the universality of these two gene regions across plants, it is suspected that this combination might not have sufficient variation to discriminate closely related species. In this study, we tested the performance of this two-locus plant barcode along with the additional plastid regions trnH-psbA, rpoC1 and rpoB and the nuclear region internal transcribed spacer (nrITS) in a group of 38 species of Lotus from the Macaronesian region. The group has radiated into the five archipelagos within this region from mid-Miocene to early Pleistocene, and thus provides both early divergent and recent radiations that pose a particularly difficult challenge for barcoding. The group also has 10 species considered under different levels of conservation concern. We found different levels of species discrimination depending on the age of the lineages. We obtained 100 % of the species identification from mainland Africa and Cape Verde when all six regions were combined. These lineages radiated >4.5 Mya; however, in the most recent radiations from the end of the Pliocene to the mid-Pleistocene (3.5-1.5 Mya), only 30 % of the species were identified. Of the regions examined, the intergenic region trnH-psbA was the most variable and had the greatest discriminatory power (18 %) of the plastid regions when analysed alone. The nrITS region was the best region when analysed alone with a discriminatory power of 26 % of the species. Overall, we identified 52 % of the species and 30 % of the endangered or threatened species within this group when all six regions were combined. Our results are consistent with those of other studies that indicate that additional approaches to barcoding will be needed in recently evolved groups, such as the inclusion of faster evolving regions from the nuclear genome. PMID:25147310

  18. Prediction of the fate of p,p'-DDE in sediment on the Palos Verdes shelf, California, USA

    USGS Publications Warehouse

    Sherwood, C.R.; Drake, D.E.; Wiberg, P.L.; Wheatcroft, R.A.

    2002-01-01

    Long-term (60-yr) predictions of vertical profiles of p,p???-DDE concentrations in contaminated bottom sediments on the Palos Verdes shelf were calculated for three locations along the 60-m isobath using a numerical solution of the one-dimensional advection-diffusion equation. The calculations incorporated the following processes: sediment deposition (or erosion), depth-dependent solid-phase biodiffusive mixing, in situ diagenetic transformation, and loss of p,p???-DDE across the sediment-water interface by two mechanisms (resuspension of sediments by wave action and subsequent loss of p,p???-DDE to the water column by desorption, and desorption from sediments to porewater and subsequent molecular diffusion to the water column). A combination of field measurements, laboratory analyses, and calculations with supporting models was used to set parameters for the model. The model explains significant features observed in measurements made every 2 years from 1981 to 1997 by the County Sanitation Districts of Los Angeles (LACSD). Analyses of available data suggest that two sites northwest of the Whites Point sewage outfalls will remain depositional, even as particulate supply from the sewage-treatment plant and nearby Portuguese Bend Landslide decreases. At these sites, model predictions for 1991-2050 indicate that most of the existing inventory of p,p???-DDE will remain buried and that surface concentrations will gradually decrease. Analyses of data southeast of the outfalls suggest that erosion is likely to occur somewhere on the southeast edge of the existing effluent-affected deposit, and model predictions for such a site showed that erosion and biodiffusion will reintroduce the p,p???-DDE to the upper layer of sediments, with subsequent increases in surface concentrations and loss to the overlying water column.

  19. Linking Slope Sedimentation, Gradient, Morphology, and Active Faulting: An Integrated Example from the Palos Verdes Slope, Southern California Borderland

    NASA Astrophysics Data System (ADS)

    Maier, K. L.; Brothers, D. S.; Paull, C. K.; McGann, M.; Caress, D. W.; Conrad, J. E.

    2015-12-01

    Seafloor gradient variations associated with restraining and releasing bends along the active (1.6-1.9 mm/yr) right-lateral Palos Verdes Fault appear to control Holocene sediment thickness, depositional environment, and morphodynamic processes along a section of the continental slope offshore Los Angeles, California. Autonomous underwater mapping vehicle (AUV), remotely operated vehicle (ROV), and shipboard methods were used to acquire a dense grid of high-resolution chirp profiles (150 m line spacing; 11 cm vertical resolution), multibeam bathymetry (2 m grid), and targeted sediment core samples (<2 m length). Detailed interpretation of Holocene deposits in the chirp profiles combined with radiocarbon dating and laser particle-size analyses allow correlation of Holocene sediment thickness and seafloor gradient with sediment gravity flow deposits. Holocene down-slope flows appear to have been generated by mass wasting processes, primarily on the upper slope (~100-200 m water depth) where shipboard multibeam bathymetry reveals submarine landslide headwall scarps in a region that has been isolated from terrigenous sediment sources throughout the Holocene. Submarine landslides appear to have transformed into sandy and organic-rich turbidity currents that created up-slope migrating sediment waves, a low relief (<5 m) fault-bounded channel, and a series of depocenters. A down-slope gradient profile and a Holocene isopach down-slope profile show that the primary depocenter occurs within a small pull-apart basin associated with a decrease in seafloor gradient of ~1.5°. Holocene sediment-flow deposits vary in number, thickness, and character with subtle changes in seabed gradient (<0.5°) and depositional environment. These results help quantify morphodynamic sensitivity to seafloor gradients and have implications for down-slope flow dynamics, deep-water depositional architecture, Holocene sediment, nutrient, and contaminant transport, and turbidite paleoseismology along

  20. Impact of Diagenesis on Biosignature Preservation Potential in Playa Lake Evaporites in Verde Formation, Arizona: Implications for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Shkolyar, S.; Farmer, J. D.

    2015-12-01

    Major priorities for Mars science include assessing the preservation potential and impact of diagenesis on biosignature preservation in aqueous sedimentary environments. We address these priorities with field and lab studies of playa evaporites of the Verde Formation (upper Pliocene) in Arizona. Evaporites studied include bottom-nucleated halite and displacive growth gypsum in magnesite-rich mudstone. These lithotypes are potential analogs for ancient lacustrine habitable environments on Mars. This study aimed to understand organic matter preservation potential under different diagenetic histories. Methods combined outcrop-scale field observations and lab analyses, including: (1) thin-section petrography to understand diagenetic processes and paragenesis; (2) X-ray powder diffraction to obtain bulk mineralogy; (3) Raman spectroscopy to identify and place phases (and kerogenous fossil remains) within a microtextural context; (4) Total Organic Carbon (TOC) analyses to estimate weight percentages of preserved organic carbon for each subfacies endmember; and (5) electron microprobe to create 2D kerogen maps semi-quantifying kerogen preservation in each subfacies. Results revealed complex diagenetic histories for each evaporite subfacies and pathways for organic matter preservation. Secondary gypsum grew displacively within primary playa lake mudstones during early diagenesis. Mudstones then experienced cementation by Mg-carbonates. Displacive-growth gypsum was sometimes dissolved, forming crystal molds. These molds were later either infilled by secondary sulfates or recrystallized to gypsum pseudomorphs with minor phases present (i.e., glauberite). These observations helped define taphonomic models for organic matter preservation in each subfacies. This work has the potential to inform in situ target identification, sampling strategies, and data interpretations for future Mars Sample Return missions (e.g., sample caching strategies for NASA's Mars 2020 mission).

  1. Benefits and Challenges of Scaling Up Expansion of Marine Protected Area Networks in the Verde Island Passage, Central Philippines

    PubMed Central

    Horigue, Vera; Pressey, Robert L.; Mills, Morena; Brotánková, Jana; Cabral, Reniel; Andréfouët, Serge

    2015-01-01

    Locally-established marine protected areas (MPAs) have been proven to achieve local-scale fisheries and conservation objectives. However, since many of these MPAs were not designed to form ecologically-connected networks, their contributions to broader-scale goals such as complementarity and connectivity can be limited. In contrast, integrated networks of MPAs designed with systematic conservation planning are assumed to be more effective—ecologically, socially, and economically—than collections of locally-established MPAs. There is, however, little empirical evidence that clearly demonstrates the supposed advantages of systematic MPA networks. A key reason is the poor record of implementation of systematic plans attributable to lack of local buy-in. An intermediate scenario for the expansion of MPAs is scaling up of local decisions, whereby locally-driven MPA initiatives are coordinated through collaborative partnerships among local governments and their communities. Coordination has the potential to extend the benefits of individual MPAs and perhaps to approach the potential benefits offered by systematic MPA networks. We evaluated the benefits of scaling up local MPAs to form networks by simulating seven expansion scenarios for MPAs in the Verde Island Passage, central Philippines. The scenarios were: uncoordinated community-based establishment of MPAs; two scenarios reflecting different levels of coordinated MPA expansion through collaborative partnerships; and four scenarios guided by systematic conservation planning with different contexts for governance. For each scenario, we measured benefits through time in terms of achievement of objectives for representation of marine habitats. We found that: in any governance context, systematic networks were more efficient than non-systematic ones; systematic networks were more efficient in broader governance contexts; and, contrary to expectations but with caveats, the uncoordinated scenario was slightly more

  2. Distribution of alpha-2-HS-glycoprotein (AHSG) phenotypes in Cabo Verde (west Africa): description of a new allele, AHSG*32.

    PubMed

    Caeiro, J L; Parra, E J; Yuasa, I; Teixeira, C; Llano, C

    1994-04-01

    The genetic polymorphism of alpha-2-HS-glycoprotein (AHSG) was studied in the population of Cabo Verde (West Africa), using isoelectric focusing in polyacrylamide gels followed by immunofixation-silver stain. AHSG frequencies are reported for the first time in a subsaharan African population. In addition to the common variants, AHSG 1 and AHSG 2, five AHSG variants were observed, including a new variant, tentatively designated AHSG 32. The allele frequencies were, AHSG*1: 0.7289, AHSG*2: 0.2111, AHSG*10: 0.0276, AHSG*3: 0.0162, AHSG*11: 0.0081, AHSG*22: 0.0065, AHSG*32:0.0016. PMID:7619771

  3. Geology of a stratigraphically complex natural gas play: Canyon Sandstones, Val Verde Basin, southwest Texas. Topical report, January-October 1993

    SciTech Connect

    Laubach, S.E.; Clift, S.J.; Hamlin, H.S.; Dutton, S.P.; Hentz, T.F.

    1994-07-01

    The report examines the influence of stratigraphy, diagenesis, natural fractures, and in situ stress on low-permeability, gas-bearing sandstone reservoirs of the Paleozoic Ozona and Sonora Canyon Sandstones of the Val Verde Basin, Texas. The main stratigraphic controls on distribution and quality of Canyon Sandstone reservoirs are submarine fan depositional patterns. These patterns are revealed in regional facies and maximum sandstone maps. Siderite cement is key to good within-sandstone reservoir quality. Natural fractures are widespread in both Ozona and Sonora Canyon sandstones. They could be future targets for advanced drilling methods, and they need to be taken into account in hydraulic fracture treatment design and reservoir management.

  4. The last 7500 cal yr B.P. of westerly rainfall in Central Chile inferred from a high-resolution pollen record from Laguna Aculeo (34°S)

    NASA Astrophysics Data System (ADS)

    Villa-Martínez, Rodrigo; Villagrán, Carolina; Jenny, Bettina

    2003-11-01

    We report multiproxy analyses of a sediment core obtained from Laguna Aculeo that spans the past 7500 years. Laguna Aculeo (33°50'S, 70°55'W) is one of the few natural inland lakes located in the Mediterranean zone of Central Chile, near the northern margin of the influence of the southern westerlies. The record shows elevated pollen counts of halophytes and seasonally drying of the lake basin prior to 5700 cal yr B.P., indicating severe aridity and warmer-than-present conditions. This was followed by the establishment of a fresh-water lake, along with an increase in arboreal and herbaceous plant diversity between 5700 and 3200 cal yr B.P. An intensification of this trend started at 3200 cal yr B.P., along with the abrupt decrease of halophytes until 100 cal yr B.P. Within this humid period, pollen accumulation rates show large-amplitude fluctuations, coeval with numerous turbidite layers, suggesting a highly variable and torrential rainfall pattern. This intense and variable precipitation regime is probably associated with the El Niño-Southern Oscillation (ENSO) phenomenon. We suggest that the modern Mediterranean climate of Central Chile was established at ˜3200 cal yr B.P. Paleovegetation and paleolimnological changes starting at 100 cal yr B.P. correlate with documented human activity surrounding the lake.

  5. Polychlorinated biphenyls in selected sites in Pasig River and Laguna Lake in the Philippines before and after a big flood event investigated under the UNU East Asia Regional POPs monitoring project.

    PubMed

    Santiago, Evangeline C; Rivas, Fritzi

    2012-08-01

    This paper reports the results of the 2009 United Nations University (UNU) East Asia Regional Monitoring of the Coastal Hydrosphere Project implemented in the Philippines. The monitoring activity focused on the concentrations of 16 specific congeners of Polychlorinated Biphenyls in selected sites in Pasig River and Laguna Lake for two sampling periods in August and in November, 2009. The results show that the total concentrations of PCBs detected in the sampling sites in August increased during the November sampling from 0.9-12.2 to 6.1-32 ng/L in Pasig River and from 0.1-0.9 to 2.9-10.8 ng/L in Laguna Lake. The increase in PCB concentrations on second sampling is attributed to the increase in contaminated sediments in the river sites and to the overflow of contaminated water in the lake sites; both of which could have been caused by the flooding event that occurred in September 2009. PMID:22617945

  6. Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes

    NASA Astrophysics Data System (ADS)

    Alabaster, T.; Storey, B. C.

    1990-06-01

    New field mapping and an integrated trace element and Nd isotopic study have been undertaken on the Jurassic-Cretaceous Larsen Harbour Complex on the island of South Georgia, recognized as a displaced part of the southern Andes ensialic, autochthonous Rocas Verdes marginal basin. Five basalt groups (Groups I-V) are identified from trace element data; initial Nd isotopic compositions suggest that they are derived from only two sources. Magmas produced during early stages of continental lithospheric attenuation (Groups I-III) were derived by varying degrees of partial melting and fractional crystallization from a large ion lithophile element (LILE)-enriched, low-ɛNd mantle source relative to normal (N)-type mid-ocean ridge basalt (MORB). Magmas produced during later stages of rifting (Groups IV and V) were, however, derived from a high-ɛNd asthenospheric mantle source similar to N-type MORB, unaffected by earlier LILE enrichment. Our data do not concur with previous suggestions that the Larsen Harbour Complex and, by implication, the Rocas Verdes formed in a supra-subduction-zone setting. On the basis of geologic and geochemical evidence, we favor basin formation along an oblique-slip margin akin to that of the Gulf of California.

  7. Connections Among the Spatial and Temporal Structures in Tidal Currents, Internal Bores, and Surficial Sediment Distributions Over the Shelf off Palos Verdes, California

    USGS Publications Warehouse

    Noble, Marlene A.; Rosenberger, Kurt J.; Xu, Jingping; Signell, Richard P.; Steele, Alex

    2009-01-01

    The topography of the Continental Shelf in the central portion of the Southern California Bight has rapid variations over relatively small spatial scales. The width of the shelf off the Palos Verdes peninsula, just northwest of Los Angeles, California, is only 1 to 3 km. About 7 km southeast of the peninsula, the shelf within San Pedro Bay widens to about 20 km. In 2000, the Los Angeles County Sanitation District began deploying a dense array of moorings in this complex region of the central Southern California Bight to monitor local circulation patterns. Moorings were deployed at 13 sites on the Palos Verdes shelf and within the northwestern portion of San Pedro Bay. At each site, a mooring supported a string of thermistors and an adjacent bottom platform housed an Acoustic Doppler Current Profiler. These instruments collected vertical profiles of current and temperature data continuously for one to two years. The variable bathymetry in the region causes rapid changes in the amplitudes and spatial structures of barotropic tidal currents, internal tidal currents, and in the associated nonlinear baroclinic currents that occur at approximate tidal frequencies. The largest barotropic tidal constituent is M2, the principal semidiurnal tide. The amplitude of this tidal current changes over fairly short along-shelf length scales. Tidal-current amplitudes are largest in the transition region between the two shelves; they increase from about 5 cm/s over the northern San Pedro shelf to nearly 10 cm/s on the southern portion of the Palos Verdes Shelf. Tidal-current amplitudes are then reduced to less than 2 cm/s over the very narrow section of the northern Palos Verdes shelf that lies just 6 km upcoast of the southern sites. Models suggest that the amplitude of the barotropic M2 tidal currents, which propagate toward the northwest primarily as a Kelvin wave, is adjusting to the short topographic length scales in the region. Semidiurnal sea-level oscillations are, as expected

  8. Single particle chemical composition, state of mixing and shape of fresh and aged Saharan dust in Morocco and at Cape Verde Islands during SAMUM I and II

    NASA Astrophysics Data System (ADS)

    Kandler, Konrad; Emmel, Carmen; Ebert, Martin; Lieke, Kirsten; Müller-Ebert, Dörthe; Schütz, Lothar; Weinbruch, Stephan

    2010-05-01

    The Saharan Mineral Dust Experiment (SAMUM) is focussed to the understanding of the radiative effects of mineral dust. During the SAMUM 2006 field campaign at Tinfou, southern Morocco, chemical and mineralogical properties of fresh desert aerosol was measured. The winter campaign of Saharan Mineral Dust Experiment II in 2008 was based in Praia, Island of Santiago, Cape Verde. This second field campaign was dedicated to the investigation of transported Saharan Mineral Dust. Ground-based and airborne measurements were performed in the winter season, where mineral dust from the Western Sahara and biomass burning aerosol from the Sahel region occurred. Samples were collected with a miniature impactor system, a sedimentation trap, a free-wing impactor, and a filter sampler. Beryllium discs as well as carbon coated nickel discs, carbon foils, and nuclepore and fiber filters were used as sampling substrates. The size-resolved particle aspect ratio and the chemical composition are determined by scanning electron microscopy and energy-dispersive X-ray microanalysis of single particles. Mineralogical bulk composition is determined by X-ray diffraction analysis. In Morocco, three size regimes are identified in the aerosol: Smaller than 500 nm in diameter, the aerosol consists of sulfates and mineral dust. Larger than 500 nm up to 50 µm, mineral dust dominates, consisting mainly of silicates, and - to a lesser extent - carbonates and quartz. Larger than 50 µm, approximately half of the particles consist of quartz. Time series of the elemental composition show a moderate temporal variability of the major compounds. Calcium-dominated particles are enhanced during advection from a prominent dust source in Northern Africa (Chott El Djerid and surroundings). More detailed results are found in Kandler et al. (2009) At Praia, Cape Verde, the boundary layer aerosol consists of a superposition of mineral dust, marine aerosol and ammonium sulfate, soot, and other sulfates as well as

  9. Modified gulf of California model for South Georgia, north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes

    SciTech Connect

    Alabaster, T.; Storey, B.C. )

    1990-06-01

    New field mapping and an integrated trace element and Nd isotopic study have been undertaken on the Jurassic-Cretaceous Larsen Harbour Complex on the island of South Georgia, recognized as a displaced part of the southern Andes ensialic, autochthonous Rocas Verdes marginal basin. Five basalt groups (Groups I-V) are identified from trace element data; initial Nd isotopic compositions suggest that they are derived from only two sources. Magmas produced during early stages of continental lithospheric attenuation (Groups I-III) were derived by varying degrees of partial melting and fractional crystallization from a large ion lithophile element (LILE)-enriched, low-{epsilon}{sub Nd} mantle source relative to normal (N)-type mid-ocean ridge basalt (MORB). Magmas produced during later stages of rifting (Groups IV and V) were, however, derived from a high-{epsilon}{sub Nd} asthenospheric mantle source similar to N-type MORB, unaffected by earlier LILE enrichment. Our data do not occur with previous suggestions that the Larsen Harbour Complex and, by implication, the Rocas Verdes formed in a supra-subduction-zone setting. On the basis of geologic and geochemical evidence, we favor basin formation along an oblique-slip margin akin to that of the Gulf of California.

  10. Movement patterns, habitat use and site fidelity of the white croaker (Genyonemus lineatus) in the Palos Verdes Superfund Site, Los Angeles, California.

    PubMed

    Wolfe, Barrett W; Lowe, Christopher G

    2015-08-01

    White croaker (Genyonemus lineatus family: Sciaenidae) are a schooling, benthic foraging fish historically associated with soft sediment and wastewater outfalls in southern California. While they are often used as an indicator species due to their high organochlorine contaminant loads, little is known of their movements in relation to contaminated habitats. A Vemco Positioning System acoustic telemetry array was used to collect fine-scale movement data and characterize the site fidelity, area use, and dispersal of 83 white croaker on the Palos Verdes Shelf Superfund Site, California over 27 months. White croaker generally demonstrated low residency and recurrence to the Palos Verdes Shelf, and were observed to be largely nomadic. However, individual behavior was highly variable. Although the entire monitored shelf was visited by tagged white croaker, habitats in 0-200 m proximity to wastewater outfalls and between 25 and 35 m depth were used most frequently. Approximately half of white croaker migrated into Los Angeles and Long Beach Harbors; areas where they may be targeted by subsistence fishers. A model framework for incorporating fish movement data into contaminant exposure estimates was developed to better understanding organochlorine contaminant exposure for planning future remediation and monitoring. PMID:26107933

  11. Boundary layer aerosol size distribution, mass concentration and mineralogical composition in Morocco and at Cape Verde Islands during SAMUM I-II

    NASA Astrophysics Data System (ADS)

    Kandler, K.; Lieke, K.

    2009-04-01

    The Saharan Mineral Dust Experiment (SAMUM) is dedicated to the understanding of the radiative effects of mineral dust. Two major field experiments were performed: A first joint field campaign took place at Ouarzazate and near Zagora, southern Morocco, from May 13 to June 7, 2006. Aircraft and ground based measurements of aerosol physical and chemical properties were carried out to collect a data set of surface and atmospheric columnar information within a major dust source. This data set combined with satellite data provides the base of the first thorough columnar radiative closure tests in Saharan dust. A second field experiment was conducted during January-February 2008, in the Cape Verde Islands region, where about 300 Tg of mineral dust are transported annually from Western Africa across the Atlantic towards the Caribbean Sea and the Amazon basin. Along its transport path, the mineral dust is expected to influence significantly the radiation budget - by direct and indirect effects - of the subtropical North Atlantic. We are lacking a radiative closure in the Saharan air plume. One focus of the investigation within the trade wind region is the spatial distribution of mixed dust/biomass/sea salt aerosol and their physical and chemical properties, especially with regard to radiative effects. We report on measurements of size distributions, mass concentrations and mineralogical composition conducted at the Zagora (Morocco) and Praia (Cape Verde islands) ground stations. The aerosol size distribution was measured from 20 nm to 500

  12. Unrest within a large rhyolitic magma system at Laguna del Maule volcanic field (Chile) from 2007 through 2013: geodetic measurements and numerical models

    NASA Astrophysics Data System (ADS)

    Le Mevel, H.; Cordova, L.; Ali, S. T.; Feigl, K. L.; DeMets, C.; Williams-Jones, G.; Tikoff, B.; Singer, B. S.

    2013-12-01

    The Laguna del Maule (LdM) volcanic field is remarkable for its unusual concentration of post-glacial rhyolitic lava coulées and domes that erupted between 25 and 2 thousand years ago. Covering more than 100 square kilometers, they erupted from 24 vents encircling a lake basin approximately 20 km in diameter on the range crest of the Andes. Geodetic measurements at the LdM volcanic field show rapid uplift since 2007 over an area more than 20 km in diameter that is centered on the western portion of the young rhyolite domes. By quantifying this active deformation and its evolution with time, we aim to investigate the storage conditions and dynamic processes in the underlying rhyolitic reservoir that drive the ongoing inflation. Analyzing interferometric synthetic aperture radar (InSAR) data, we track the rate of deformation. The rate of vertical uplift is negligible from 2003 to 2004, accelerates from at least 200 mm/yr in 2007 to more than 300 mm/yr in 2012, and then decreases to 200mm/yr in early 2013. To describe the deformation, we use a simple model that approximates the source as a 8 km-by-6 km sill at a depth of 5 km, assuming a rectangular dislocation in a half space with uniform elastic properties. Between 2007 and 2013, the modeled sill increased in volume by at least 190 million cubic meters. Four continuous GPS stations installed in April 2012 around the lake confirm this extraordinarily high rate of vertical uplift and a substantial rate of radial expansion. As of June 2013, the rapid deformation persists in the InSAR and GPS data. To describe the spatial distribution of material properties at depth, we are developing a model using the finite element method. This approach can account for geophysical observations, including magneto-telluric measurements, gravity surveys, and earthquake locations. It can also calculate changes in the local stress field. In particular, a large increase in stress in the magma chamber roof could lead to the initiation and

  13. Long-term slip rates of the Elsinore-Laguna Salada fault, southern California, by U-series Dating of Pedogenic Carbonate in Progressively Offset Alluvial fan Remnants.

    NASA Astrophysics Data System (ADS)

    Fletcher, K. E.; Rockwell, T. K.; Sharp, W. D.

    2007-12-01

    The Elsinore-Laguna Salada (ELS) fault is one of the principal strands of the San Andreas fault system in southern California, however its seismic potential is often de-emphasized due to previous estimates of a low slip rate. Nevertheless, the fault zone has produced two historic earthquakes over M6, with the 1892 event estimated at >M7; thus further investigation of the long-term slip rate on the ELS fault is warranted. On the western slopes of the Coyote Mountains (CM), southwest Imperial Valley, a series of alluvial fans are progressively offset by the Elsinore fault. These fans can be correlated to their source drainages via distinctive clast assemblages, thereby defining measurable offsets on the fault. Dating of the CM fans (to compute slip rates), however, is challenging. Organic materials appropriate for C-14 dating are rare or absent in the arid, oxidizing environment. Cosmogenic surface exposure techniques are limited by the absence of suitable sample materials and are inapplicable to numerous buried fan remnants that are otherwise excellent strain markers. Pedogenic carbonate datable by U-series, however, occurs in CM soil profiles, ubiquitously developed in fan gravels, and is apparent in deposits as young as ~1 ka. In CM gravels 10's ka and older, carbonate forms continuous, dense, yellow coatings up to 3 mm thick on the undersides of clasts. Powdery white carbonate may completely engulf clasts, but is not dateable. Carefully selected samples of dense, innermost carbonate lamina weighing 10's of milligrams and analyzed by TIMS, are geochemically favorable for precise U-series dating (e.g., U = 1-1.5 ppm, median 238U/232Th ~ 7), and yield reproducible ages for coatings from the same microstratigraphic horizon (e.g., 48.2 ± 2.7 and 49.9 ± 2.2 ka), indicating that U-Th systems have remained closed and that inherited coatings, though present, have been avoided. Accordingly, U-series on pedogenic carbonate provides reliable minimum ages for deposition of

  14. Rock-magnetic signatures of aeolian activity, precipitation and extreme runoff events from the sediments of Laguna Potrok Aike (southern Patagonia) since 51,200 cal BP

    NASA Astrophysics Data System (ADS)

    St-Onge, G.; Lisé-Pronovost, A.; Gogorza, C. S. G.; Haberzettl, T.; Jouve, G.; Francus, P.; Ohlendorf, C.; Gebhardt, C.; Zolitschka, B.

    2014-12-01

    The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Here we use high-resolution u-channel, as well as discrete rock-magnetic and physical grain size data from the 106 m long core (~51,200 cal BP) of site 2 of the ICDP Potrok Aike maar lake Sediment Archive Drilling project (PASADO) in order to develop magnetic proxies of dust and wind intensity, as well as precipitation and extreme runoff events. Rock-magnetic analyses indicate the magnetic mineral assemblage is dominated by detrital magnetite and that low field magnetic susceptibility (kLF) can be interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale. On shorter time scales however, kLF variability is correlated to ferrimagnetic grain size and coercivity. Comparison to physical grain-size data indicates that the median destructive field of the isothermal remanent magnetisation (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension and that MDFIRM can be interpreted as a wind-intensity proxy, with stronger winds capable of transporting coarser silts to the lake. In addition, about half of the sedimentary sequence is composed of mass movement deposits (MMDs). Within these MMDs, two distinct sedimentary facies can easily be identified. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of a gyroremanent magnetisation (GRM) acquired during demagnetisation of the natural remanent magnetisation (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetisation

  15. Recent temperature trends in the South Central Andes reconstructed from sedimentary chrysophyte stomatocysts in Laguna Escondida (1742 m a.s.l., 38°28 S, Chile)

    NASA Astrophysics Data System (ADS)

    De Jong, R.; Schneider, T.; Hernández-Almeida, I.; Grosjean, M.

    2016-02-01

    In this study we present a quantitative, high resolution reconstruction of past austral winter length in the Chilean Andes at 38°S from AD 1920 to 2009. For Laguna Escondida, a nearly pristine lake situated on the flanks of the Andes at 1740 m above sea level, past variability in the duration of the winter season (Days T4 °C) was reconstructed. Because high elevation meteorological stations are absent in this region, the reconstruction provides novel insights into recent temperature trends in the central-southern Andes. As a cold-season temperature proxy, we used chrysophyte stomatocysts. This novel proxy for cold season temperature was so far applied successfully in the European Alps and Pyrenees but has not yet been tested in the Southern Hemisphere. The reconstruction in this study was based on a newly developed Transfer Function to estimate Days T4 °C (number of consecutive days with surface water temperatures at or below 4 °C) from sedimentary stomatocyst assemblages (R2boot = 0.8, RMSEPboot = 28.7 days (= half the standard deviation)). To develop a high quality TF model, sediment traps and thermistors were placed in thirty remote lakes along an altitude gradient (420-2040 m a.s.l.). Complete materials and data were collected in 24 lakes after one year. Detailed statistical analyses indicate that modern stomatocysts primarily respond to the length of the cold season. The TF model was then applied to the sedimentary stomatocysts from a 210Pb-dated short core of L. Escondida. Comparison to independent reanalysis data showed that reconstructed changes in Days T4°C provides detailed information on winter-spring temperature variability since AD 1920. The reconstruction shows that recent warming (onset in AD 1980) in the southern Chilean Andes was not exceptional in the context of the past century. This is in strong contrast to studies from the Northern Hemisphere. The finding is also in contrast to the cooling temperature trends which were detected using

  16. The Nd-, Sr- and Pb-isotopic character of lavas from Taal, Laguna de Bay and Arayat volcanoes, southwestern Luzon, Philippines: Implications for arc magma petrogenesis

    NASA Astrophysics Data System (ADS)

    Mukasa, Samuel B.; Flower, Martin F. J.; Miklius, Asta

    1994-07-01

    Following the amalgamation of a collage of pre-Neogene terranes largely by strike-slip and convergence mechanisms to form the Philippine islands, volcanic chains, related to oppositely dipping subduction zones, developed along the eastern and western margins of the archipelago. There is ample field evidence that this volcanic activity, predominantly calc-alkaline in chemical character, had commenced by the Oligocene. Volcanoes resulting from subduction along the Manila-Negros trench in the west (e.g. Taal, Laguna de Bay and Arayat) form a high-angle linear array, trending away from the MORE field on Pb-isotopic covariation diagrams; have the highest Sr- and lowest Nd-isotopic compositions, of the two chains (but nevertheless plotting above bulk earth on the 87Sr/ 86Sr versus 143Nd/ 144Nd covariation diagram); and exhibit Sm/Nd and Rb/Sr values that are lower and higher, respectively, than the estimated values for bulk earth. While the Sm/Nd and Rb/Sr characteristics are common to both chains, volcanoes associated with the Philippine-East Luzon trench have Pb-isotopic compositions that fall in the Indian Ocean MORB field and that require time-integrated evolution in a high Th/U environment. They also have higher Nd- and lower Sr-isotopic ratios. The source materials of Philippine volcanoes, therefore, have undergone varied recent enrichments in LILE, as indicated by the decoupling of isotopic and elemental ratios. These enrichments, particularly for the western volcanoes, cannot be entirely due to small degrees of partial melting in the mantle wedge, considering that they were accompanied by elevations in radiogenic Pb. Elevated Pb ratios are best explained by the introduction of subducted, continentally derived sediments. The sedimentary component in the western volcanoes is probably the South China Sea sediments derived largely from Eurasia. That this component is not available in the Philippine-East Luzon trench is reflected by the fact that the eastern volcanoes

  17. Expanding Geophysical and Geochemical Investigation of Causes of Extraordinary Unrest at the Laguna del Maule (Rhyolitic) Volcanic Field, Southern Andes, Chile

    NASA Astrophysics Data System (ADS)

    Singer, B. S.

    2014-12-01

    The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007 the crust here has been inflating at an astonishing rate of 25 cm/yr. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ~20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. Swarms of volcano-tectonic and long period earthquakes, mostly of M < 2, have occurred beneath the most recent rhyolite coulees on the southwestern and southern margins of the 20 km diameter ring of silicic vents. With support from the US NSF and the Chilean government (SERNAGEOMIN and OVDAS) we are seizing the unique opportunity to investigate, over the next 5 years, the dynamics of this large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively underway. This collaboration involves scientists and students at: University of Wisconsin-Madison, Georgia Tech, Cornell, University of Alberta, Simon Fraser University, University of Chile-Santiago, CONICET/University of San Juan-Argentina, Nanyang Technological University-Singapore, SERNAGEOMIN, OVDAS, USGS, and SEGEMAR-Argentina. Team members will be introduced in this presentation. Our approach includes augmenting the OVDAS array of 6 permanent seisic stations with 40 additional instruments to conduct tomographic, receiver function and ambient noise studies. We continue to collect 4-D gravity data from 37 stations. Surface deformation is monitored via cGPS at 5 permanent receivers and InSAR data. A magnetotelluric survey across the Andes at 36o S is planned. Geochemical studies include mineral zoning and U-Th disequilibrium of zircons to constrain the timing of magma intrusion and

  18. The Nd-, Sr- and Pb-isotopic character of lavas from Taal, Laguna de Bay and Arayat volcanoes, southwestern Luzon, Philippines: Implications for arc magma petrogenesis

    USGS Publications Warehouse

    Mukasa, S.B.; Flower, M.F.J.; Miklius, Asta

    1994-01-01

    Following the amalgamation of a collage of pre-Neogene terranes largely by strike-slip and convergence mechanisms to form the Philippine islands, volcanic chains, related to oppositely dipping subduction zones, developed along the eastern and western margins of the archipelago. There is ample field evidence that this volcanic activity, predominantly calc-alkaline in chemical character, had commenced by the Oligocene. Volcanoes resulting from subduction along the Manila-Negros trench in the west (e.g. Taal, Laguna de Bay and Arayat) form a high-angle linear array, trending away from the MORE field on Pb-isotopic covariation diagrams; have the highest Sr- and lowest Nd-isotopic compositions, of the two chains (but nevertheless plotting above bulk earth on the 87Sr/86Sr versus 143Nd/144Nd covariation diagram); and exhibit Sm/Nd and Rb/Sr values that are lower and higher, respectively, than the estimated values for bulk earth. While the Sm/Nd and Rb/Sr characteristics are common to both chains, volcanoes associated with the Philippine-East Luzon trench have Pb-isotopic compositions that fall in the Indian Ocean MORB field and that require time-integrated evolution in a high Th/U environment. They also have higher Nd- and lower Sr-isotopic ratios. The source materials of Philippine volcanoes, therefore, have undergone varied recent enrichments in LILE, as indicated by the decoupling of isotopic and elemental ratios. These enrichments, particularly for the western volcanoes, cannot be entirely due to small degrees of partial melting in the mantle wedge, considering that they were accompanied by elevations in radiogenic Pb. Elevated Pb ratios are best explained by the introduction of subducted, continentally derived sediments. The sedimentary component in the western volcanoes is probably the South China Sea sediments derived largely from Eurasia. That this component is not available in the Philippine-East Luzon trench is reflected by the fact that the eastern volcanoes

  19. New data on the Lateglacial period of SW Europe: a high resolution multiproxy record from Laguna de la Roya (NW Iberia)

    NASA Astrophysics Data System (ADS)

    Muñoz Sobrino, C.; Heiri, O.; Hazekamp, M.; van der Velden, D.; Kirilova, E. P.; García-Moreiras, I.; Lotter, A. F.

    2013-11-01

    High-resolution multiproxy analyses were performed on a 128 cm section of organic sediments accumulated in a small mountain lake in NW Iberia (Laguna de la Roya, 1608 m asl). The pollen stratigraphy together with radiocarbon dating provided the basis for a chronology ranging from 15,600 to 10,500 cal yr BP. Chironomid-inferred July air temperatures suggest a temperature range from 7 to 13 °C, also evidencing two well-established cold periods which may be equivalent to the INTIMATE stages GS-2a and GS-1. Furthermore, a number of short cold events (with summer temperatures dropping about 0.5-1 °C) appear intercalated within the Lateglacial Interstadial (possibly equivalent to the INTIMATE cold events GI-1d, GI-1c2 and GI-1b) and the early Holocene (possibly equivalent to the 11.2 k event). The temperature variations predicted by our reconstruction allow explaining the changes in local conditions and productivity of the lake inferred from the biological record of the same sediment core. Furthermore, they also agree with the local and regional vegetation dynamics, and the main oscillations deduced for the vegetation belts. Based on its chronology our multiproxy record indicates a similar temperature development in NW Iberia as inferred by the Greenland δ18O record, the marine deep-sea records off the Atlantic Iberian Margin, and other chironomid-based Lateglacial temperature reconstructions from Europe. Nevertheless, the impact of most of the less intense Lateglacial/early Holocene cold events in NW Iberia was most probably limited to very sensitive sites that were very close to ecotonal situations. Particularly, our new pollen record indicates that they were represented as three minor environmental crises occurring during the Lateglacial Interestadial in this area. The Older Dryas event (in our usage corresponding to the Aegelsee Oscillation in Central Europe and event GI-1d in central Greenland) has previously been described in this region, but its age and

  20. A basic radial dike swarm of Boa Vista (Cape Verde Archipelago); its significance in the evolution of the island

    NASA Astrophysics Data System (ADS)

    Ancochea, Eumenio; Hernán, Francisco; Huertas, María José; Brändle, José Luis

    2012-10-01

    A basic radial dike swarm unrelated to other basic units of Boa Vista (Cape Verde Archipelago) has been localized and characterized in the central sector of the island. According to new radiometric data three main stages in the evolution of Boa Vista are distinguished: the earlier (the Old Volcanic Complex: 17-16 Ma) is equivalent to the shield building stage of Hawaii and the later (the Recent Volcanics (8-4 Ma) is in some aspects comparable to the post-erosional stage. An important intermediate essentially felsic stage (the Trachytic-Phonolitic Complex: 14.3-12.8 Ma) followed the basaltic shield stage. This felsic stage has equivalents in some other oceanic islands as the Canary Islands, specially Gran Canaria, Tenerife, and La Gomera. The central sector of Boa Vista is also occupied by the Felsic Subvolcanic Complex, a unit consisting of phonolitic breccias, syenites and monzonites that represent the Trachytic-Phonolitic Complex hypabyssal roots. The felsic rocks as a whole constitute half of the total amount of igneous rocks on the island making up Boa Vista, the island with the highest percentage of felsic rocks in the Central Atlantic Ocean. More than 200 dikes of the basic radial swarm intruding the Felsic Subvolcanic Complex have been measured. The intensity of the multiple dike injection is sometimes rather high, roughly a dike every 5 m. The individual dikes have an observable mean length of about 300 m. The composition of these dikes is always foiditic (nephelinites, melilitites, and limburgites), slightly different in composition (more alkaline and richer in incompatible elements) to the other basic units of the island (the Old Volcanic Complex and the Recent Volcanics). The radial dikes converge in an area located NW of the geometrical center of Boa Vista, a zone where the hypothetical center of the Old Volcanic Complex and the Trachytic-Phonolitic Complex edifices must also have been situated. The ages obtained from the dikes (between 14.8 and 11.5 Ma

  1. Structure, composition and age of the small islands of Santa Luzia, Branco and Raso (Cape Verde Archipelago)

    NASA Astrophysics Data System (ADS)

    Ancochea, Eumenio; Huertas, María José; Hernán, Francisco; Brändle, José Luis; Alonso, Mar

    2015-09-01

    The northern alignment of Cape Verde Archipelago contains three small islands in its central sector: Santa Luzia, Branco and Raso on which there is very scarce geological, petrological or geochronological information available. The three islands along with the island of São Vicente arise on a continuous underwater relief less than 50 m deep and about 70 km long that formed from separate volcanic edifices. The southernmost island, Raso is formed by accumulation of several tens of lava flows and some remaining strombolian cones. An erosion surface covered by sediments allows the separation of two different episodes of growth: the lower one older than 2 Ma, and the upper one between 0.9 and 1.2 Ma. The smaller island of Branco is the remnant of a large stratovolcano about 6 km in radius, 1000 m of altitude and between 5 and 6 Ma in age. Santa Luzia, the northernmost and largest island of this particular group is essentially a remaining rift zone between 4 and 7 Ma old, at least 600 m high, about 10 km long and 7 km wide. The SE extreme of the island is occupied by rocks of an older partially submarine stage of growth which, also include gabbroic intrusions crossed by a dense network of dikes whose age may be estimated in 8 Ma or more. On the contrary, the NW end shows the only remains of late post-erosion activity that is of much less volumetric importance and it has been dated between 0.8 and 1.4 Ma. The three islands as a whole are formed by moderately or strongly alkaline, basic and ultrabasic rocks similar to those found in the neighboring island of São Vicente. Ultraalkaline rocks only appear in Raso and differentiate types as trachyandesites and phonolites are exclusively found in Santa Luzia. The similar age found for the main stages of growth recorded in the mentioned four islands and, even more, in the other two islands: Santo Antão and São Nicolau situated at the end of the Barlovento alignment, are not easily comprehensible with evolution models

  2. Chronology of the seismic and ground deformation precursors of the 2014 Fogo Volcano - Cape Verde Islands - eruption.

    NASA Astrophysics Data System (ADS)

    Day, S. J.; Faria, B. V. E.

    2015-12-01

    The most recent eruption of Fogo Volcano, Cape Verde Islands started on the 23 November 2014 at 10h15 (CVT), after 19 years of quiescence. Several months before the begging of the eruption, the seismic activity started to deviate from the baseline, with the appearance of a class of events that was not recorded before then. This activity was characterized by a significant number of instrumentally detected, very low magnitude seismic events, sometimes more than 100 per day. In September those events became more energetic and analysis indicated that they could be of volcano-tectonic (VT) origin. The first VT event to be located was on 4 October with a 2.5 local magnitude: it was located slightly to the south of the middle of the island at between 15.5 and 16 km depth. This was deeper than normal for background VT events and coincided with the depth of last magma equilibration in the 1995 eruption. It was therefore interpreted as a possible precursor of an eruption: thus the alert level was raised to level 2, and the civil protection authorities were informed. On the following weeks the rate of VT events slightly increased and the focal depths became shallower. Very sporadic harmonic volcano tremor episodes and very few and weak long-period events were also recorded. From about the 15 to 21 November, the VT activity rate oscillated, and hypocentres tended to gather in the vicinity of an inferred dike emplacement and at shallower depth - 6 to 5 km b.s.l. On the first hours of the 22 November seismic rate increased from 3 to 6 events per hour and the events became more energetic. After 19h30 (CVT), when the magma reached the ductile-brittle transition zone (5 to 4 km b.s.l), the seismic rate increased again to more than one event per minute; earthquake magnitudes increased as well. At about 03h00 (CVT) the tilt records shown a prominent ground deformation. Continuous volcanic tremor started only one to half an hour before the start of the eruption.

  3. Heavy metals of Santiago Island (Cape Verde) top soils: Estimated Background Value maps and environmental risk assessment

    NASA Astrophysics Data System (ADS)

    Cabral Pinto, M. M. S.; Ferreira da Silva, E.; Silva, M. M. V. G.; Melo-Gonçalves, P.

    2015-01-01

    In this work we present maps of estimates of background values of some harmful metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn) in the soils of Santiago Island, Cape Verde, analyse their relationships with the geological cartography, and assess their environmental risks. The geochemical survey (soil sampling at a spatial resolution of 3 sites per 10 km2, sample preparation, geochemical analysis, data treatment, and mapping) was conducted following the guidelines proposed by the International Projects IGCP 259 and IGCP 360. The concentration of the selected elements was determined in the fraction <2 mm. Each sample was digested with aqua regia and analysed by ICP-MS. The Estimated Background Value spatial distributions of the studied metals are found to be strongly linked to the geological cartography. These links are identified by a direct comparison of the geochemical maps with the geological cartography, and confirmed by either simple statistics and a Principal Component Analysis. The metals with higher loadings in the first Principal Component, Ni, Cr, Co, Cu, and V, clearly show the influence of a lithology rich in siderophile elements, typical of basic rocks and of its related minerals. The elements with higher loadings in the second Principal Component, Mn, Zn, Pb, As, Hg, and Cd, are chalcophile elements, except for Mn, but an anthropogenic contamination for these elements cannot be discarded. We propose an index to numerically access the environmental risk of one element, which we denominate by Environmental Risk Index, and a Multi-element Index which is simply the average taken over all elements. The occurrence of values greater than 1 in the maps of the Environmental Risk Index shows where the content of the respective element is above the permissible levels according to the available legislation for agricultural and residential purposes. The same applies to the multi-element risk index maps. High values of these risk indices are found, both for

  4. Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde islands

    NASA Astrophysics Data System (ADS)

    Fomba, K. W.; Müller, K.; van Pinxteren, D.; Herrmann, H.

    2013-05-01

    Size-resolved trace metal concentrations of 15 elements in aerosol particles at the Cape Verde Atmospheric Observatory (CVAO) under remote background conditions were investigated through analysis of aerosol samples collected during intensive field studies from January 2007 to November 2011 using total reflection x-ray fluorescence (TXRF). The identification of the main air mass origin that influence remote marine aerosol in the northern tropical Atlantic has been investigated. In total, 317 samples were collected. The dataset was analyzed according to the main air mass inflow at the station. We found that remote conditions make up about 45% of the meteorological conditions in a year at CVAO and thus the northern tropical Atlantic. Surprisingly, air masses from North America are often responsible for higher trace metal concentrations in this region. Elements such as Zn, Pb, Cu, Cr, Ni, and V were mostly found in the submicron size fractions, while elements with dominant crustal or oceanic origin such as Fe, Ti, Mn, Sr, and Rb were found in the coarse fractions (>1 μm). The highest metal concentrations, especially for Zn (3.23 ng m-3), Cu (0.81 ng m-3), Sr (2.63 ng m-3), and Cr (0.53 ng m-3), were observed in air masses originating from North America and the concentrations were within the same concentration range to those reported previously in the literature for remote marine aerosols. Fe (12.26 ng m-3), Ti (0.91 ng m-3), and Mn (0.35 ng m-3) showed higher concentrations when air mass came from Europe and the Canary Islands. Pb concentration was low (<0.20 ng m-3) and did not vary significantly with air mass direction. The low Pb concentration is indicative of the complete phase-out of leaded gasoline even in African countries. Crustal enrichment factor values decreased from fine to coarse-mode particles with low values (<4) observed for Fe, Mn, and Rb, and high values (>20) for Zn, Cu, Ni, Cr, Pb, and Se. The observed enrichment of the elements was attributed to

  5. Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Fomba, K. W.; Müller, K.; van Pinxteren, D.; Herrmann, H.

    2012-11-01

    Size-resolved trace metal concentrations of 15 elements in aerosol particles at the Cape Verde Atmospheric Observatory (CVAO) under remote background conditions were investigated through analysis of aerosol samples collected during intensive field studies from January 2007 to November 2011 using total reflection x-ray fluorescence (TXRF). The identification of the main air mass origin that influence remote marine aerosol in the northern tropical Atlantic has been investigated. In total 317 samples were collected. The dataset was analyzed according to the main air mass inflow at the station. We found that remote conditions make up about 45% of the meteorological conditions in a year at CVAO and thus the northern tropical Atlantic. Surprisingly, air masses from North America are often responsible for higher trace metal concentrations in this region. Elements such as Zn, Pb, Cu, Cr, Ni, and V were mostly found in the submicron size fractions while elements with dominant crustal or oceanic origin such as Fe, Ti, Mn, Sr, and Rb, were found in the coarse fractions (>1 μm). The highest metal concentrations especially for Zn (3.23 ng m-3), Cu (0.81 ng m-3), Sr (2.63 ng m-3), and Cr (0.53 ng mm-3), were observed in air masses originating from North America and the concentrations were within the same concentration range to those reported previously in the literature for remote marine aerosols. Fe (12.26 ng m-3), Ti (0.91 ng m-3) and Mn (0.35 ng m-3) showed higher concentrations when air mass came from Europe and the Canary Islands. Pb concentration was low (< 0.20 ng m-3) and did not vary significantly with air mass direction. The low Pb concentration is indicative of the complete phased out of leaded gasoline even in African countries. Crustal enrichment factor values decreased from fine to coarse mode particles with low values (< 4) observed for Fe, Mn, and Rb and high values (> 20) for Zn, Cu, Ni, Cr, Pb, and Se. The observed enrichment of the elements was attributed to

  6. Tectonic geomorphology, deformation history, and slip-rate estimate along the Palos Verdes Fault, offshore Southern California

    NASA Astrophysics Data System (ADS)

    Brothers, D. S.; Conrad, J. E.; Maier, K. L.; Paull, C. K.; McGann, M.

    2014-12-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. Despite its proximity to metropolitan Los Angeles, the recent activity and earthquake hazards associated with the PVF are poorly constrained. To characterize the near seafloor fault morphology, Late Pleistocene-Holocene slip-rate and tectonic influences on slope sedimentary processes, a grid of high-resolution multibeam bathymetry and chirp sub-bottom profiles were acquired with the Monterey Bay Aquarium Research Institute's (MBARI) Autonomous Underwater Vehicle (AUV). The AUV surveys were focused along the continental slope ~25 km south of Long Beach in water depths between 250 and 600 m, where the PVF crosses the slope. AUV multibeam bathymetry data gridded at 2-m resolution and chirp profiles are merged with 25-m resolution ship-based multibeam bathymetry and seismic-reflection profiles. Vibracores collected with the MBARI Remotely Operated Vehicle (ROV) and ship-based USGS gravity cores provided radiocarbon dates for stratigraphic horizons offset by the PVF. Recent deformation is expressed as a well-defined seafloor lineation and offset Late Pleistocene-Holocene sub-bottom reflections. Curvilinear scarps associated with an upper submarine landslide (~450 m water depth), a buried slump block, and a lower submarine landslide (~525 m water depth) have been right-laterally offset by 55±3, 55±5, and 40±5 meters, respectively. The age of the upper scarp is bracketed between 23-31 kyr BP, which yields an average slip rate across the PVF of 1.6-2.4 mm/yr. However, our best estimate for the age of the upper landslide is ~ 31 kyr BP, which yields a right-lateral slip-rate of 1.8 mm/yr. Vertical growth faulting observed along a subtle transtensional fault-bend suggests that at least two surface ruptures occurred during the Holocene. In summary, these results indicate that the offshore

  7. Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 2: The Chaco Halo, Mesa Verde, Pajarito Plateau/Bandelier, and Zuni Archaeological Regions

    USGS Publications Warehouse

    Benson, L.V.

    2011-01-01

    Chemical and nutrient analyses of 471 soil samples from 161 sites within four archaeological regions (Pajarito Plateau/Bandelier, Zuni, Mesa Verde, and the Chaco Halo) were combined with historical climate data in order to evaluate the agricultural productivity of each region. In addition, maize productivity and field-life calculations were performed using organic-nitrogen (N) values from the upper 50 cm of soil in each region and a range (1-3%/year) of N-mineralization rates. The endmember values of this range were assumed representative of dry and wet climate states. With respect to precipitation and heat, the Pajarito Plateau area has excellent agricultural potential; the agricultural potentials of the Zuni and Mesa Verde regions are good; and the agricultural potential of the Chaco Halo is poor. Calculations of N mineralization and field life indicate that Morfield Valley in Mesa Verde should be able to provide 10 bu/ac of maize for decades (without the addition of N) when organic N-mineralization rates exceed 2%. Productivity and field-life potential decrease in the following order: Zuni, Mesa Verde, Bandelier, Chaco Halo. The Chaco Halo is very unproductive; e. g., 10 bushels per acre can be achieved within the Halo only from soils having the highest organic N concentration (third quartile) and which undergo the highest rate (3%) of N mineralization. ?? 2010 US Government.

  8. Simulation of streamflow and estimation of recharge to the Edwards aquifer in the Hondo Creek, Verde Creek, and San Geronimo Creek watersheds, south-central Texas, 1951-2003

    USGS Publications Warehouse

    Ockerman, Darwin J.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the San Antonio Water System, constructed three watershed models using the Hydrological Simulation Program—FORTRAN (HSPF) to simulate streamflow and estimate recharge to the Edwards aquifer in the Hondo Creek, Verde Creek, and San Geronimo Creek watersheds in south-central Texas. The three models were calibrated and tested with available data collected during 1992–2003. Simulations of streamflow and recharge were done for 1951–2003. The approach to construct the models was to first calibrate the Hondo Creek model (with an hourly time step) using 1992–99 data and test the model using 2000–2003 data. The Hondo Creek model parameters then were applied to the Verde Creek and San Geronimo Creek watersheds to construct the Verde Creek and San Geronimo Creek models. The simulated streamflows for Hondo Creek are considered acceptable. Annual, monthly, and daily simulated streamflows adequately match measured values, but simulated hourly streamflows do not. The accuracy of streamflow simulations for Verde Creek is uncertain. For San Geronimo Creek, the match of measured and simulated annual and monthly streamflows is acceptable (or nearly so); but for daily and hourly streamflows, the calibration is relatively poor. Simulated average annual total streamflow for 1951–2003 to Hondo Creek, Verde Creek, and San Geronimo Creek is 45,400; 32,400; and 11,100 acre-feet, respectively. Simulated average annual streamflow at the respective watershed outlets is 13,000; 16,200; and 6,920 acre-feet. The difference between total streamflow and streamflow at the watershed outlet is streamflow lost to channel infiltration. Estimated average annual Edwards aquifer recharge for Hondo Creek, Verde Creek, and San Geronimo Creek watersheds for 1951–2003 is 37,900 acrefeet (5.04 inches), 26,000 acre-feet (3.36 inches), and 5,940 acre-feet (1.97 inches), respectively. Most of the recharge (about 77 percent for the three watersheds

  9. A VIS-RS spectroscopy-based warm season temperature reconstruction from the southern Chilean Andes (38.5° S) derived from the sediments of Laguna Escondida (1742m. a.s.l.) since AD 770

    NASA Astrophysics Data System (ADS)

    Schneider, Tobias; De Jong, Rixt; Grosjean, Martin

    2014-05-01

    Laguna Escondida is a remote, relatively high altitude lake in the southern Chilean Andes. It is situated just north of the region that experiences year-round influence of the Southern Hemisphere Westerlies. In our study area, currently the influence of westerly air flow primarily influences the winter season and depends on long term variability in the position and strength of the Westerlies. Although the region to the south (northern Patagonia) is relatively well-studied, only a few climatic reconstructions are available for the climatic transition zone in which our study site is located. This study thus aims to provide climatic reconstructions for a relatively poorly studied region of South America which lies in a climatically important transition zone. These reconstructions may also contribute to our current knowledge on latitudinal variations in the position of the Southern Hemisphere Westerly wind belt. In this study, the sediments of Laguna Escondida (38°28'S; 70°58'W) were examined in detail with scanning methods (VIS-RS spectroscopy: spectral analyses within the visible light range, 380-730 nm; magnetic susceptibility) and carefully dated using 210Pb, 137Cs and 14C measurements. VIS-RS scanning provided a proxy for the amount of chlorins (chlorophyll-a derivates) in the sediment, which was verified by comparison to (HPLC) pigment analyses. In addition, classical methods (C:N, grainsize distribution) were applied, as well as detailed analyses of sedimentary chrysophyte stomatocysts. Calibration-in-Time (CIT) was used to detect whether any of these sediment properties reflected past temperature variability. Our findings show that the chlorin content in the sediments of Laguna Escondida was highly and significantly correlated (r= 0.63, p= 0.039, 3-yearly filtered) with warm season temperatures back to AD 1940. Prior to that, meteorological data were increasingly sparse and the chronological error of the age-depth model was too large to be suitable for CIT

  10. Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago.

    PubMed

    de Pina-Araujo, Isabel Inês M; Guimarães, Monick L; Bello, Gonzalo; Vicente, Ana Carolina P; Morgado, Mariza G

    2014-01-01

    HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010-2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1-75) and 47 (IQR = 12-84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented

  11. Profile of the HIV Epidemic in Cape Verde: Molecular Epidemiology and Drug Resistance Mutations among HIV-1 and HIV-2 Infected Patients from Distinct Islands of the Archipelago

    PubMed Central

    de Pina-Araujo, Isabel Inês M.; Guimarães, Monick L.; Bello, Gonzalo; Vicente, Ana Carolina P.; Morgado, Mariza G.

    2014-01-01

    HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010–2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1–75) and 47 (IQR = 12–84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be

  12. Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 1. Executive summary, RL-17 test report, and gas conversion proposals. Export trade information

    SciTech Connect

    Not Available

    1991-03-28

    The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the first of three volumes and it is divided into the following sections: (1) Executive Summary; (2) Hydrogen Damage Assessment; (3) RL-17 Gas Conversion Proposal; (4) RL-10 and RL-11 Gas Conversion Proposals.

  13. Modern and subrecent spatial distribution and characteristics of sediment infill controlled by internal depositional dynamics, Laguna Potrok Aike (southern Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Kastner, S.; Ohlendorf, C.; Haberzettl, T.; Lücke, A.; Maidana, N. I.; Mayr, C.; Schäbitz, F.; Zolitschka, B.

    2009-04-01

    Situated in the dry steppe environment of south-eastern Patagonia the 100 m deep and max. 770 ka old maar lake Laguna Potrok Aike (51°58'S, 70°23'W) has a high potential as a palaeolimnological key site for the reconstruction of terrestrial palaeoclimate conditions. As this area is sensitive to variations in southern hemispheric wind and pressure systems the lake holds a unique lacustrine record of palaeoclimatic and palaeoecological variability. Depositional changes inferred from the lacustrine sediment sequence as well as subaerial and subaquatic lake level terraces provide detailed information about the water budget of the lake related to the variability of the Southern Hemispheric Westerlies. For this reason the lake was chosen as an ICDP drilling site in 2008 within the "Potrok Aike maar lake sediment archive drilling project" (PASADO). Based on high resolution multi-proxy investigations of the last 16,000 years carried out on a 18.9 m long sediment record (Haberzettl et al., 2007; Mayr et al., 2009; Wille et al., 2007) this study focuses on the understanding of internal depositional dynamics which control the characteristics and spatial distribution of the sediment infill of this lake. Furthermore, it provides information improving the accuracy of the interpretation of the long sediment record recovered within the PASADO project. A survey of the spatial sediment distribution was carried out in 2005 using 46 gravity cores of up to 49 cm length covering a range of water depths from 9 to 100 m. All 46 cores were scanned with X-ray fluorescence technique and for magnetic susceptibility with up to 1 mm spatial resolution. Using Ca and Ti as well as magnetic susceptibility data the cores were correlated and linked to the established age model (Haberzettl et al., 2005). As these parameters vary considerably and not consistently within the suite of littoral cores, a correlation prior to the 2005 sediment surface is solely based on cores from water depths exceeding

  14. Diagenesis and late-stage porosity development in the pennsylvanian strawn formation, val verde basin, Texas, U.S.A

    USGS Publications Warehouse

    David, Newell K.; Goldstein, R.H.; Burdick, C.J.

    2005-01-01

    The Middle Pennsylvanian (Desmoinesian) Strawn Formation in the Trans-Pecos area of Texas was deposited during relative tectonic quiescence that prevailed before rapid infilling of the Val Verde Basin. It represents one of a series of backstepping carbonate ramps formed on the craton side of this foreland basin. Strawn Formation carbonate rocks in three cores - Conoco Anna McClung #3-1, Alex Mitchell S2-1R, and Creek Ranch #10-1 - show several shallowing-up ward sequences, each a few meters thick. The Creek Ranch core displays the deepest-water characteristics of the three cores; the lower part of this core is dominated by graded bedding. The Mitchell and McClung cores contain skeletal-rich carbonates. Both of these cores display characteristics of shallow-water bank or lagoonal environments. All three cores have approximately the same diagenetic history. Primary fluid inclusions indicate early porosity-occluding interparticle and mold-filling calcite precipitated from water with a narrow range of salinities. Modal salinities are that of seawater, but slightly lesser salinities (indicating mixing of seawater and meteoric water) and slightly greater salinities (indicating evaporative concentration of seawater) are also indicated. The influence of meteoric groundwater can be detected by stable-isotope analyses of the early cements at stratigraphic levels that correlate to the tops of the major shallowing-upward depositional sequences. However, subaerial exposure surfaces are not demonstrated in these cores but were likely to be present updip. Most porosity is cement-reduced vugs, dissolution-enlarged (and cement-reduced) molds (> 1/16 mm, < 4 mm), and fractures. Minor intraparticle, intercrystalline, and shelter porosity is also present. Reservoir porosity is caused by fracturing and a late-stage dissolution event. Dissolution in the Creek Ranch core is not as pronounced as in the other cores because of a dearth of skeletal material. Porous zones in the McClung and

  15. Seasonal variations in stable isotope ratios of atmospheric nitrate in a tropical boundary layer environment (Cape Verde Observatory).

    NASA Astrophysics Data System (ADS)

    Savarino, Joël.; Morin, Samuel; Erbland, Joseph; Grannec, Francis; Patey, Matthew; Achterberg, Eric

    2010-05-01

    seasonal cycle of the nitrate isotope systematic at the Cap Verde (lat. 16° 85'N, lon. 24° 87' W) characteristic of a tropical oceanic boundary layer. Both ?17O and δ15N display a marked seasonal cycle in opposing phase. ?17O values are maximum in winter (≠ƒ 30 permil) and minimal in summer (≠ƒ 26 permil) while δ15N display the opposite trend with maximum in summer (-2.9 permil) and minimum in winter (-8.8 permil). No correlation is found with the nitrate atmospheric loading for any of the isotope ratio. ?17O seasonal variations correlate with the monthly averaged daytime depletion of ozone whose seasonal variation have been attributed mainly to halogen oxides. This observation suggests that part of the maximum nitrate oxygen anomaly (?17O) could result from halogen chemistry in the marine boundary layer via probably the strong NOx oxidant BrO. For δ15N, a broad correlation is found with the atmospheric concentration of NO and solar radiation intensity, confirming that δ15N of nitrate retranscribes principally a source and/or a photochemical equilibrium effect between NO and NO2.

  16. Multi-payload Multi-platform Tactical Monitoring and Evaluation of the 2014 Eruption of Fogo, Cabo Verde

    NASA Astrophysics Data System (ADS)

    Ferrucci, Fabrizio; Day, Simon; Hirn, Barbara; Faria, Bruno; Zoffoli, Simona

    2015-04-01

    The 2014 eruption on the flank of Pico volcano on the island of Fogo (Cape Verde), started ca. 11h30 UTC on November 23rd. It gave rise to a three-branch lava flow running ca. 4 km to the north, 3 to the west and 2 to the south, totaling about 10 million cubic meters in one month, that destroyed two villages and left about 1,000 homeless among the ca. 37,000 inhabitants of Fogo. This mostly effusive event differs from the much better-known, simultaneous Holuhraun eruption in northern Iceland as its instant (thermal) Radiant Flux barely exceeded 10 GW, whereas the latter peaked over 100 GW. Conversely, whereas the Holuhraun lavas have flowed over uninhabited land, and the associated risk is negligible, the Fogo lavas impacted a populated area and would have produced even greater damage had they escaped the confines of the Mt.Amarelo lateral collapse scar within which Pico do Fogo is located, and flowed down the populated outer slopes of Fogo. Upon request of INMG in the second day of eruption, we brought immediate remote sensing and modelling support, based on all observation means able to provide estimates of physical parameters related to power released, lava effusion rates and flow distance to run, along with also quantitative evaluations of eruptive trends and styles. As needs were scaled on the immediate near-daily release of coherent information concerning ongoing lava effusion, we considered that multispectral electro-optical sensors were more useful than radar sensors. We chose to run in parallel a 'tactical' observation line, based on the automated analytical solving of subresolution equation systems in multispectral data with top revisit rates (15 minutes with SEVIRI onboard the geostationary MSG-3, and 4 to 8 hours with MODIS onboard the polar Terra and Aqua) along with a 'strategic' line centred on the automated equation solving in high-to-very high spatial resolution LEO data provided by CEOS (multispectral pixel footprints ranging from 4 m2 of Pleiades

  17. Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial

    PubMed Central

    Nava-Aguilera, Elizabeth; Arosteguí, Jorge; Morales-Perez, Arcadio; Suazo-Laguna, Harold; Legorreta-Soberanis, José; Hernandez-Alvarez, Carlos; Fernandez-Salas, Ildefonso; Paredes-Solís, Sergio; Balmaseda, Angel; Cortés-Guzmán, Antonio Juan; Serrano de los Santos, René; Coloma, Josefina; Ledogar, Robert J; Harris, Eva

    2015-01-01

    Objective To test whether community mobilization adds effectiveness to conventional dengue control. Design Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. Setting Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. Participants Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85 182 residents in 18 838 households. Interventions A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention—chemical-free prevention of mosquito reproduction—to its own circumstances. All clusters continued the government run dengue control program. Main outcome measures Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. Results With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of

  18. The application of Heat Capacity Mapping Mission (HCMM) thermal data to snow hydrology. [Salt Verde Watershed and the southern Sierra Nevada

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.; Smallwood, M. D.; Willand, J. H.

    1981-01-01

    The application of HCMM thermal infrared data to snow hydrology and the prediction of snowmelt runoff was evaluated. Data for the Salt Verde watershed in central Arizona and the southern Sierra Nevada in California were analyzed and compared to LANDSAT and NOAA satellite data, U-2 thermal data, and other correlative data. It was determined that HCMM thermal imagery provides data as accurate for snow mapping as does visible imagery, and that in comparison with the reslution of other satellite imagery, it may be the most useful. Data from the HCMM thermal channel, with careful calibration, provides useful snow surface temperature data for hydrological purposes. An approach to an automated method of analysis is presented.

  19. Geology of the epithermal Ag-Au Huevos Verdes vein system and San José district, Deseado massif, Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Dietrich, Andreas; Gutierrez, Ronald; Nelson, Eric P.; Layer, Paul W.

    2012-03-01

    The San José district is located in the northwest part of the Deseado massif and hosts a number of epithermal Ag-Au quartz veins of intermediate sulfidation style, including the Huevos Verdes vein system. Veins are hosted by andesitic rocks of the Bajo Pobre Formation and locally by rhyodacitic pyroclastic rocks of the Chon Aike Formation. New 40Ar/39Ar constraints on the age of host rocks and mineralization define Late Jurassic ages of 151.3 ± 0.7 Ma to 144.7 ± 0.1 Ma for volcanic rocks of the Bajo Pobre Formation and of 147.6 ± 1.1 Ma for the Chon Aike Formation. Illite ages of the Huevos Verdes vein system of 140.8 ± 0.2 and 140.5 ± 0.3 Ma are 4 m.y. younger than the volcanic host rock unit. These age dates are among the youngest reported for Jurassic volcanism in the Deseado massif and correlate well with the regional context of magmatic and hydrothermal activity. The Huevos Verdes vein system has a strike length of 2,000 m, with several ore shoots along strike. The vein consists of a pre-ore stage and three main ore stages. Early barren quartz and chalcedony are followed by a mottled quartz stage of coarse saccharoidal quartz with irregular streaks and discontinuous bands of sulfide-rich material. The banded quartz-sulfide stage consists of sulfide-rich bands alternating with bands of quartz and bands of chlorite ± illite. Late-stage sulfide-rich veinlets are associated with kaolinite gangue. Ore minerals are argentite and electrum, together with pyrite, sphalerite, galena, chalcopyrite, minor bornite, covellite, and ruby silver. Wall rock alteration is characterized by narrow (< 3 m) halos of illite and illite/smectite next to veins, grading outward into propylitic alteration. Gangue minerals are dominantly massive quartz intergrown with minor to accessory adularia. Epidote, illite, illite/smectite, and, preferentially at deeper levels, Fe-chlorite gangue indicate near-neutral pH hydrothermal fluids at temperatures of >220°C. Kaolinite occurring with

  20. eVerdEE: a web-based screening life-cycle assessment tool for European small and medium-sized enterprises

    NASA Astrophysics Data System (ADS)

    Naldesi, Luciano; Buttol, Patrizia; Masoni, Paolo; Misceo, Monica; Sára, Balázs

    2004-12-01

    "eLCA" is a European Commission financed project aimed at realising "On line green tools and services for Small and Medium-sized Enterprises (SMEs)". Knowledge and use of Life Cycle Assessment (LCA) by SMEs are strategic to introduce the Integrated Product Policy (IPP) in Europe, but methodology simplification is needed. LCA requires a large amount of validated general and sector specific data. Since their availability and cost can be insuperable barriers for SMEs, pre-elaborated data/meta-data, use of standards and low cost solutions are required. Within the framework of the eLCA project an LCA software - eVerdEE - based on a simplified methodology and specialised for SMEs has been developed. eVerdEE is a web-based tool with some innovative features. Its main feature is the adaptation of ISO 14040 requirements to offer easy-to-handle functions with solid scientific bases. Complex methodological problems, such as the system boundaries definition, the data quality estimation and documentation, the choice of impact categories, are simplified according to the SMEs" needs. Predefined "Goal and Scope definition" and "Inventory" forms, a user-friendly and well structured procedure are time and cost-effective. The tool is supported by a database containing pre-elaborated environmental indicators of substances and processes for different impact categories. The impact assessment is calculated automatically by using the user"s input and the database values. The results have different levels of interpretation in order to identify the life cycle critical points and the improvement options. The use of a target plot allows the direct comparison of different design alternatives.

  1. Influence of the Portuguese Bend landslide on the character of the effluent-affected sediment deposit, Palos Verdes margin, southern California

    USGS Publications Warehouse

    Kayen, R.E.; Lee, H.J.; Hein, J.R.

    2002-01-01

    Historic accretion of sediment on the Palos Verdes margin off Los Angeles County, CA, is dominated by two sources, effluent from Whites Point outfall and sediment eroded from the toe of Portuguese Bend landslide. In this paper, we document the recent history of sedimentation from these non-marine sources from 1937 until the late 1990s, and attempt to estimate the amount of material preserved on the shelf. Toward that end, we characterized offshore sediment by physical and geotechnical testing, using non-destructive gamma-ray whole-core logging techniques and conventional geotechnical strength tests, and X-ray diffraction. Results are reported within a geographic information system framework that allows for: (1) the evaluation of the spatial variability of the measured properties, and (2) assessment of the influence of these properties on processes affecting the effluent-affected Sediment layer. In the inner shelf, material eroded by wave action from the toe of the Portuguese Bend landslide since 1956 has contributed 5.7-9.4 million metric tons (Mmt) of sediment, from a total eroded mass of 12.1 Mmt. A lesser fraction (???2.7Mmt) of sediment is incorporated into the mid- and outer-shelf effluent-affected sediment layer. Evidence from X-ray diffractograms clearly indicates that landslide material has mixed with the mid- and outer-shelf effluent. From 1937-1987, it is estimated that 3.8 Mmt of solid anthropogenic effluent was discharged into the water column and onto the Palos Verdes Shelf.

  2. Concept of biogenic ferromanganese crust formation: coccoliths as bio-seeds in crusts from Central Atlantic Ocean (Senghor Seamount/Cape Verde).

    PubMed

    Wang, Xiaohong; Peine, Florian; Schmidt, Alexander; Schröder, Heinz C; Wiens, Matthias; Schlossmacher, Ute; Müller, Werner E G

    2011-05-01

    At depths of 2,000 to 3,000 m, seamounts from the Cape Verde archipelago (Central Atlantic Ocean) are largely covered with ferromanganese crusts. Here we studied 60 to 150 mm thick crusts from the Senghor Seamount (depth: 2257.4 m). The crusts have a non lamellated texture and are covered with spherical nodules. The chemical composition shows a dominance of MnO2 (26.1%) and Fe2O3 (38.8%) with considerable amounts of Co (0.74%) and TiO2 (2.1%). Analysis by scanning electron probe microanalyzer (EPMA) revealed a well defined compositional zonation of micro-layers; the distribution pattern of Mn does not match that of Fe. Analysis by high resolution scanning electron microscopy (SEM) revealed that coccospheres/coccoliths exist in the crust material as microfossils; most of the coccospheres/coccoliths are not intact. The almost circular coccoliths belong to the type of heterococcoliths and are taxonomically related to species of the family Calcidiscaceae. By energy dispersive X-ray spectroscopic analysis an accumulation of the coccoliths in the Mn- and Fe rich micronodules was detected. Focused ion beam assisted SEM mapping highlighted that the coccoliths in the crust are Mn rich, suggesting that the calcareous material of the algal skeleton has been replaced by Mn-minerals. We conclude that a biologically induced mechanism has been involved in the formation of the crusts, collected from the Cape Verde archipelago from depths of 2,000 to 3,000 m in the mixing region between the oxygen-minimum surface zone and the oxygen-rich deep waters; the deposition process might have been triggered by chemical reactions during the dissolution of the Ca-carbonate skeletons of the coccoliths allowing Mn(II) to oxidize to Mn(IV) and in turn to deposit this element in the crust material. PMID:21615032

  3. Volcano-stratigraphic and structural evolution of Brava Island (Cape Verde) based on 40Ar/ 39Ar, U-Th and field constraints

    NASA Astrophysics Data System (ADS)

    Madeira, José; Mata, João; Mourão, Cyntia; Brum da Silveira, António; Martins, Sofia; Ramalho, Ricardo; Hoffmann, Dirk L.

    2010-10-01

    Three volcano-stratigraphic units were identified at Brava Island in the Cape Verde Archipelago on the basis of field relationships, geologic mapping and 40Ar/ 39Ar and U-Th ages. The Lower Unit comprises a 2-to-3 Ma-old submarine volcanic sequence that represents the seamount stage. It is composed of nephelinitic/ankaramitic hyaloclastites and pillow lavas, which are cut by abundant co-genetic dikes. Plutonic rocks of an alkaline-carbonatite complex, which intruded the submarine sequence 1.8 to 1.3 Ma ago, constitute the Middle Unit. A major erosional surface developed between 1.3 and ~ 0.25 Ma. The post-erosional volcanism recorded in the Upper Unit started 0.25 Ma ago and is dominated by phonolitic magmatism. This phase is characterised by explosive phreato-magmatic and magmatic activity that produced block and ash flow, surge, and pyroclastic fall deposits and numerous phreato-magmatic craters. Effusive events are represented by lava domes and coulées. One peculiarity of Brava is the occurrence of carbonatites in both the plutonic complex and the post-erosional phase as extrusive volcanics. The intrusive carbonatites are younger than those occurring on Fogo, Santiago and Maio islands. Young (Upper Pleistocene to Holocene) extrusive carbonatites occurring in the late stages of volcanism are unknown in other Cape Verde islands. The occurrence of pillow lavas and hyaloclastites above the present sea level (up to 400 m) and raised Upper Pleistocene beaches indicates continuous uplift of Brava since the seamount stage. By dating raised marine markers, uplift rates were estimated at between 0.2 and 0.4 mm/a. The evolution of Brava was controlled by faults with directions similar to those described for Fogo, suggesting a common stress field. A detailed geological map (1/25,000) of Brava is presented.

  4. Geology, geochronology, and geochemistry of basaltic flows of the Cat Hills, Cat Mesa, Wind Mesa, Cerro Verde, and Mesita Negra, central New Mexico

    USGS Publications Warehouse

    Maldonado, F.; Budahn, J.R.; Peters, L.; Unruh, D.M.

    2006-01-01

    The geochronology, geochemistry, and isotopic compositions of basaltic flows erupted from the Cat Hills, Cat Mesa, Wind Mesa, Cerro Verde, and Mesita Negra volcanic centres in central New Mexico indicate that each of these lavas had unique origins and that the predominant mantle involved in their production was an ocean-island basalt type. The basalts from Cat Hills (0.11 Ma) and Cat Mesa (3.0 Ma) are similar in major and trace element composition, but differences in MgO contents and Pb isotopic values are attributed to a small involvement of a lower crustal component in the genesis of the Cat Mesa rocks. The Cerro Verde rock is comparable in age (0.32 Ma) to the Cat Hills lavas, but it is more radiogenic in Sr and Nd, has higher MgO contents, and has a lower La/Yb ratio. This composition is explained by the melting of an enriched mantle source, but the involvement of another crustal component cannot be disregarded. The Wind Mesa rock is characterized by similar age (4.01 Ma) and MgO contents, but it has enriched rare-earth element contents compared with the Cat Mesa samples. These are attributed to a difference in the degree of partial melting of the Cat Mesa source. The Mesita Negra rock (8.11 Ma) has distinctive geochemical and isotopic compositions that suggest a different enriched mantle and that large amounts of a crustal component were involved in generating this magma. These data imply a temporal shift in magma source regions and crustal involvement, and have been previously proposed for Rio Grande rift lavas. ?? 2006 NRC Canada.

  5. Geology, geochemistry, geochronology, and economic potential of Neogene volcanic rocks in the Laguna Pedernal and Salar de Aguas Calientes segments of the Archibarca lineament, northwest Argentina

    NASA Astrophysics Data System (ADS)

    Richards, J. P.; Jourdan, F.; Creaser, R. A.; Maldonado, G.; DuFrane, S. A.

    2013-05-01

    This study presents new geochemical, geochronological, isotopic, and mineralogical data, combined with new geological mapping for a 2400 km2 area of Neogene volcanic rocks in northwestern Argentina near the border with Chile, between 25°10‧S and 25°45‧S. The area covers the zone of intersection between the main axis of the Cordillera Occidental and a set of NW-SE-trending structures that form part of the transverse Archibarca lineament. This lineament has localized major ore deposits in Chile (e.g., the late Eocene La Escondida porphyry Cu deposit) and large volcanic centers such as the active Llullaillaco and Lastarría volcanoes on the border between Chile and Argentina, and the Neogene Archibarca, Antofalla, and Cerro Galán volcanoes in Argentina. Neogene volcanic rocks in the Laguna Pedernal and Salar de Aguas Calientes areas are mostly high-K calc-alkaline in composition, and range from basaltic andesites, through andesites and dacites, to rhyolites. Magmatic temperatures and oxidation states, estimated from mineral compositions, range from ~ 1000 °C and ∆FMQ ≈ 1.0-1.5 in andesites, to ~ 850 °C and ∆FMQ ≈ 1.5-2.0 in dacites and rhyolites. The oldest rocks consist of early-middle Miocene andesite-dacite plagioclase-pyroxene-phyric lava flows and ignimbrites, with 40Ar/39Ar ages ranging from 17.14 ± 0.10 Ma to 11.76 ± 0.27 Ma. Their major and trace element compositions are typical of the Andean Central Volcanic Zone, and show strong crustal contamination trends for highly incompatible elements such as Cs, Rb, Th, and U. These rocks are geochemically grouped as sub-suite 1. This widespread intermediate composition volcanism was followed in the middle-late Miocene by a period of more focused rhyodacitic flow-dome complex formation. These felsic rocks are characterized by less extreme enrichments in highly incompatible elements, and increasing depletion of heavy rare earth elements. These rocks are geochemically grouped as sub-suite 2. The

  6. Climate history of the Southern Hemisphere Westerlies belt during the last glacial-interglacial transition revealed from lake water oxygen isotope reconstruction of Laguna Potrok Aike (52° S, Argentina)

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Lücke, A.; Wissel, H.; Mayr, C.; Enters, D.; Kim, K. Ja; Ohlendorf, C.; Schäbitz, F.; Zolitschka, B.

    2014-12-01

    The Southern Hemisphere Westerlies (SHW) play a crucial role in large-scale ocean circulation and global carbon cycling. Accordingly, the reconstruction of how the latitudinal position and intensity of the SHW belt changed during the last glacial termination is essential for understanding global climatic fluctuations. The southernmost part of the South American continent is the only continental mass intersecting a large part of the SHW belt. However, due to the scarcity of suitable palaeoclimate archives continuous proxy records back to the last glacial are rare in southern Patagonia. Here, we show an oxygen isotope record from cellulose and purified bulk organic matter of submerged aquatic moss shoots from Laguna Potrok Aike (52° S, 70° W), a deep maar lake located in semi-arid, extra-Andean Patagonia, covering the last glacial-interglacial transition (26 000 to 8500 cal BP). Based on the highly significant correlation between oxygen isotope values of modern aquatic mosses and their host waters and abundant well-preserved moss remains in the sediment record a high-resolution reconstruction of the lake water oxygen isotope (δ18Olw-corr) composition is presented. The reconstructed δ18Olw-corr values for the last glacial are ca. 3‰ lower than modern values, which can best be explained by generally cooler air temperatures and changes in the moisture source area, together with the occurrence of permafrost leading to a prolonged lake water residence time. Thus, the overall glacial δ18Olw-corr level until 21 000 cal BP is consistent with a scenario of weakened or absent SHW at 52° S compared to the present. During the last deglaciation, reconstructed δ18Olw-corr values reveal a significant two-step rise describing the detailed response of the lake's hydrological balance to this fundamental climatic shift. Rapid warming is seen as the cause of the first rise of ca. 2&permil, in δ18Olw-corr during the first two millennia of deglaciation (17 600 to 15 600 cal BP

  7. Uplifted ophiolitic rocks on Isla Gordon, southernmost Chile: implications for the closure history of the Rocas Verdes marginal basin and the tectonic evolution of the Beagle Channel region

    NASA Astrophysics Data System (ADS)

    Cunningham, W. D.

    1994-04-01

    A succession of mafic rocks that includes gabbro, sheeted dikes and deformed pillow basalts has been mapped in detail on Isla Gordon, southernmost Chile and is identified as an upper ophiolitic complex representing the uplifted floor of the Late Jurassic-Early Cretaceous Rocas Verdes marginal basin. The complex was uplifted, deformed, and regionally metamorphosed prior to the intrusion of an undeformed 90 Ma granodiorite that cuts the complex. The complex appears para-autochthonous, is gently tilted to the northeast and is internally sheared by near-vertical foliation zones. No evidence for obduction was observed although the base of the complex is not exposed. The ophiolitic rocks have been regionally metamorphosed to mid-upper greenschist levels. Isla Gordon is bounded by the northwest and southwest arms of the Beagle Channel, two important structural boundaries in the southernmost Andes that are interpreted to have accommodated north-side-up and left-lateral displacements. Directly north of Isla Gordon is the Cordillera Darwin metamorphic complex that exposes the highest grade metamorphic rocks in the Andes south of Peru. On the north coast of Isla Gordon a volcaniclastic turbidite sequence that is interpreted to have been deposited above the mafic floor is metamorphosed to lower greenschist levels in strong metamorphic contrast to amphibolite-grade othogneisses exposed in Cordillera Darwin only 2 km away across the northwest arm of the Beagle Channel. The profound metamorphic break across the northwest arm of the Beagle Channel and the regional northeast tilt of the ophiolitic complex are consistent with the previously proposed hypothesis that Isla Gordon represents the upper plate to an extensional fault that accommodated tectonic unroofing of Cordillera Darwin. However, limited structural evidence for extension was identified in this study to support the model and further work is needed to determine the relative importance of contractional, extensional and

  8. Modelling the biophysical and socio-economic potential of Sustainable Land Management (SLM) in the Cabo Verde drylands: The PESERA-DESMICE approach.

    NASA Astrophysics Data System (ADS)

    Baptista, Isaurinda; Irvine, Brian; Fleskens, Luuk; Geissen, Violette; Ritsema, Coen

    2015-04-01

    Rainfall variability, the occurrence of extreme drought and historic land management practice have been recognised as contributing to serious environmental impact in Cabo Verde. Investment in conservation measures has become visible throughout the landscape. Despite this the biophysical and socioeconomic impacts of the conservation measures have been poorly assessed and documented. As such a concerted approach based on the DESIRE project continues to consult stackholders and carry out field trials for selected conservation technologies. Recent field trials have demonstrated the potential of conservation technologies but have also demonstrated that yield variability between sites and between years is significant. This variability appears to be driven by soil and rainfall characteristics However, where detailed field studies have only run for a limited period they have not as yet encountered the full range of climatic variability; thus a modelling approach is considered to capture a greater range of climatic conditions. The PESERA-DESMICE model is adopted which considers the biophysical and social economic benefits of the conservation technologies against a local baseline condition. PESERA is adopted as climate is implicitly considered in the model and, where appropriate, in-situ conservation measures are considered as an annual input to the soil. The DESMICE component of the model considers the suitability of the conservation measures and their costs and benefits in terms of environmental conditions and market access. Historic rainfall statistics are calculated from field measurements in the Ribeira Seca catchment. These statistics are used to generate a series of 50 year rainfall realisations to capture a fuller range of the climatic conditions. Each realisation provides a unique time-series of rainfall and through modelling can provide a simulated time-series of crop yield. Additional realisations and model simulations add to an envelope of the potential crop

  9. CO2-dependent fractional crystallization of alkaline silicate magmas and unmixing of carbonatites within the intrusive complexes of Brava Island (Cape Verde)

    NASA Astrophysics Data System (ADS)

    Weidendorfer, D.; Schmidt, M. W.; Mattsson, H. B.

    2014-12-01

    Intrusive carbonatites often occur in intimate association with SiO2-undersaturated rocks such as melilitites, nephelinites, syenites and phonolites. The occurrence of carbonatites on five of the 10 main islands of the Cape Verde hotspot argues for a CO2-enriched mantle source. Whether alkali-poor carbonatites on the Cape Verdes directly represent small mantle melt fractions or form by extreme fractionation and/or liquid immiscibility from a CO2-rich silicate magma remains a matter of debate. This study focuses on the pyroxenites, nephelinites, ijolites, syenites, phonolites and carbonatites of the intrusive unit of Brava Island. This relative complete series allows for the deduction of a CO2-dependent fractionation pathway from the most primitive basanitic dikes towards phonolitic compositions through an ijolitic series. Major and trace element whole rock and mineral composition trends can be reproduced by fractionating a sequence of olivine, augite, perovskite, biotite, apatite, sodalite and FeTi-oxides, present as phenocrysts in the rocks corresponding to their fractionation interval. To reproduce the observed chemistry of the alkaline silicate rocks a total fractionation of ~87% is required. The melts evolve towards the carbonatite-silicate miscibility gap, an initial CO2 of 0.5 wt% would be sufficient to maintain CO2-saturation in the more evolved compositions. The modelled carbonatite compositions, conjugate to nepheline-syenites to phonolites, correspond well to the observed ones except for an alkali-enrichment with respect to the natural samples. The alkali-depleted nature of the small carbonatite intrusions and dikes on Brava is likely a consequence of fluid-release to the surrounding wall-rocks during crystallization, where fenitization can be observed. The trace element chemistry of primary carbonates and also cpx within both, the carbonatites and the associated silicate rocks, substantiates our fractionation model. Furthermore, carbonatite and silicate

  10. Molecular detection of Anaplasma platys, Ehrlichia canis, Hepatozoon canis and Rickettsia monacensis in dogs from Maio Island of Cape Verde archipelago.

    PubMed

    Lauzi, Stefania; Maia, João P; Epis, Sara; Marcos, Ricardo; Pereira, Cristina; Luzzago, Camilla; Santos, Marta; Puente-Payo, Pablo; Giordano, Alessia; Pajoro, Massimo; Sironi, Giuseppe; Faustino, Augusto

    2016-07-01

    Tick-borne diseases are emerging worldwide and have an important zoonotic relevance. Dogs play an important role in the epidemiology of several zoonotic tick-borne pathogens acting as sentinels and/or reservoirs. This study focused on the molecular identification of tick-borne pathogens in blood samples of 153 autochthonous asymptomatic dogs in Maio Island, Cape Verde archipelago. Eighty-four (54.9%) dogs were positive for one or more pathogens. Fifty-five (35.9%) dogs were infected with Hepatozoon canis, 53 (34.6%) with Anaplasma platys, five (3.3%) with Ehrlichia canis and Rickettsia monacensis, an emerging human pathogen, was also identified in a single dog (0.7%). The former three pathogens cause important canine tick-borne diseases that are transmitted or potentially transmitted by Rhipicephalus sanguineus s.l., the only hard tick identified in Cape Verde. Furthermore, Wolbachia spp. was amplified from the blood of one dog. None of the dogs were positive for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Midichloria mitochondrii, Bartonella spp., Babesia spp. or Theileria spp. Fifty-four (35.3%) animals showed single infections and 30 (19.6%) co-infections, with A. platys and H. canis co-infection being the most frequent (28 dogs, 18.3%). The frequency of E. canis infection was statistically different among age groups (P=0.017), being higher among dogs older than 4 years compared to younger dogs. Infection by A. platys was also statistically different among age groups (P=0.031), being higher in dogs younger than 2 years compared to older dogs. The statistical analyses showed no significant association of PCR positivity with gender or location. The frequency of tick-borne pathogens detected in dogs in Maio Island, including R. monacensis, highlights the need to improve diagnosis and control in order to prevent the risk of transmission of these pathogens among dogs and humans living in or travelling to this touristic island. PMID:27177475

  11. Small scale inhomogeneity in the mantle source of the Cape Verde hotspot is probably related to plume complexity: implications from Sr, Nd and high precision Pb isotopes and geochemistry

    NASA Astrophysics Data System (ADS)

    Holm, P. M.; Sørensen, R. V.

    2009-04-01

    The volcanic rocks of one of the major islands of the Cape Verde hotspot have been investigated in order to test mantle plume models. From the centre of the Cape Verde Rise an array of islands trend west, the northern HIMU-type Cape Verde Islands. Of these, São Nicolau (SN) is the easternmost and Santo Antão the westernmost. Sixty samples of primitive (MgO = 9-14 wt%) basanitic composition from SN that represent the four volcanic stages of the 9 - 0.1 Ma evolution of the island have been analysed for Sr, Nd and high precision Pb isotopic composition. Pb ranges to a less radiogenic composition than on SA [1] and has lower 8/4 than the rocks of the southern EM1-type Cape Verde islands. Most SN lavas have a young HIMU character with negative 7/4. The most radiogenic Pb at SN is less thorogenic than Pb at SA. Temporal variation is also evident: An intermediate age group of samples have particularly low La/Nb = 0.4 - 0.5 and the least LREE-enrichment for SN. The youngest group of rocks has the lowest Zr/Nb = 2.5 - 3.0 and the most unradiogenic Sr and radiogenic Nd in the archipelago. At least four of the mantle source components for the SN magmas are different from any found in the SA magmas. High precision Pb data allow identification of parallel trends for northern SN and the southern island Santiago, which therefore must have unrelated source components. For the northern Cape Verde islands source compositions vary from E to W as well as with time. This cannot be explained by stationary enriched lithosphere components. The derivation of melts from a complex plume source is modelled. [1] Holm P.M., Wilson J.R., Christensen B.P., Hansen S.L., Hein K.M., Mortensen A.K., Pedersen R., Plesner S., and Runge M.K. (2006) JPetrol 47, 145-189.

  12. Comparison of Skylab and LANDSAT images for geologic mapping in Northern Arizona. [Shivwits Plateau, Verde Valley, Coconino Plateau, and Red Lake in Arizona

    NASA Technical Reports Server (NTRS)

    Goetz, A. F. H. (Principal Investigator); Abrams, M. J.; Gillespie, A. R.; Siegal, B. S.; Elston, D. P.; Lucchitta, I.; Wu, S. S. C.; Sanchez, A.; Dipaola, W. D.; Schafer, F. J.

    1976-01-01

    The author has identified the following significant results. It was found that based on resolution, the Skylab S190A products were superior to LANDSAT images. Based on measurements of shoreline features in Lake Mead S190A images had 1.5 - 3 times greater resolution than LANDSAT. In general, the higher resolution of the Skylab data yielded better discrimination among rock units, but in the case of structural features, lower sun angle LANDSAT images (50 deg) were superior to higher sun angle Skylab images (77 deg). The most valuable advantage of the Skylab over the LANDSAT image products is the capability of producing stereo images. Field spectral reflectance measurements on the Coconino Plateau were made in an effort to determine the best spectral band for discrimination of the six geologic units in question, and these bands were 1.3, 1.2, 1.0, and 0.5 microns. The EREP multispectral scanner yielded data with a low signal to noise ratio which limited its usefulness for image enhancement work. Sites that were studied in Arizona were Shivwits Plateau, Verde Valley, Coconino Plateau, and Red Lake. Thematic maps produced by the three classification algorithms analyzed were not as accurate as the maps produced by photointerpretation of composites of enhanced images.

  13. Tortricid moths reared from the invasive weed Mexican palo verde, Parkinsonia aculeata, with comments on their host specificity, biology, geographic distribution, and systematics.

    PubMed

    Brown, John W; Segura, Ricardo; Santiago-Jiménez, Quiyari; Rota, Jadranka; Heard, Tim A

    2011-01-01

    As part of efforts to identify native herbivores of Mexican palo verde, Parkinsonia aculeata L. (Leguminosae: Caesalpinioideae), as potential biological control agents against this invasive weed in Australia, ten species of Tortricidae (Lepidoptera) were reared from Guatemala, Mexico, Nicaragua, and Venezuela: Amorbia concavana (Zeller), Platynota rostrana (Walker), Platynota helianthes (Meyrick), Platynota stultana Walsingham (all Tortricinae: Sparganothini), Rudenia leguminana (Busck), Cochylis sp. (both Tortricinae: Cochylini), Ofatulena duodecemstriata (Walsingham), O. luminosa Heinrich, Ofatulena sp. (all Olethreutinae: Grapholitini), and Crocidosema lantana Busck (Olethreutinae: Eucosmini). Significant geographic range extensions are provided for O. duodecemstriata and R. leguminana. These are the first documented records of P. aculeata as a host plant for all but O. luminosa. The four species of Sparganothini are polyphagous; in contrast, the two Cochylini and three Grapholitini likely are specialists on Leguminosae. Ofatulena luminosa is possibly host specific on P. aculeata. Host trials with Rudenia leguminana also provide some evidence of specificity, in contrast to historical rearing records. To examine the possibility that R. leguminana is a complex of species, two data sets of molecular markers were examined: (1) a combined data set of two mitochondrial markers (a 781-basepair region of cytochrome c oxidase I (COI) and a 685-basepair region of cytochrome c oxidase II) and one nuclear marker (a 531-basepair region of the 28S domain 2); and (2) the 650-basepair "barcode" region of COI. Analyses of both data sets strongly suggest that individuals examined in this study belong to more than one species. PMID:21521138

  14. Calculating the diffusive flux of persistent organic pollutants between sediments and the water column on the Palos Verdes shelf superfund site using polymeric passive samplers.

    PubMed

    Fernandez, Loretta A; Lao, Wenjian; Maruya, Keith A; Burgess, Robert M

    2014-04-01

    Passive samplers were deployed to the seafloor at a marine Superfund site on the Palos Verdes Shelf, California, USA, and used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water. A model of Fickian diffusion across a thin water boundary layer at the sediment-water interface was used to calculate flux of contaminants due to molecular diffusion. Concentrations at four stations were used to calculate the flux of DDE, DDD, DDMU, and selected PCB congeners from sediments to the water column. Three passive sampling materials were compared: PE strips, POM strips, and SPME fibers. Performance reference compounds (PRCs) were used with PE and POM to correct for incomplete equilibration, and the resulting POP concentrations, determined by each material, agreed within 1 order of magnitude. SPME fibers, without PRC corrections, produced values that were generally much lower (1 to 2 orders of magnitude) than those measured using PE and POM, indicating that SPME may not have been fully equilibrated with waters being sampled. In addition, diffusive fluxes measured using PE strips at stations outside of a pilot remedial sand cap area were similar to those measured at a station inside the capped area: 240 to 260 ng cm(-2) y(-1) for p,p'-DDE. The largest diffusive fluxes of POPs were calculated at station 8C, the site where the highest sediment concentrations have been measured in the past, 1100 ng cm(-2) y(-1) for p,p'-DDE. PMID:24564763

  15. Investigation of the application of HCMM thermal data to snow hydrology. [Salt-Verde watershed, Arizona and the Sierra Nevada Mountains, California

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. Comparison of the thermal IR band temperatures over the rapidly melting snowcover in a number of locations in the Salt-Verde Arizona watershed by the U-2 high altitude multispectral scanner, with temperatures for these same locations measured by the corresponding HCMM pass, indicate that the U-2 temperatures are typically 5 C higher than the values analyzed from the HCMM infrared digital printout. Results tend to substantiate findings of other investigators that with the offset that has been applied to all HCMM data, the HCMM temperature values may, in fact, actually be 5 C too low. Analysis of differences between the HCMM day and night temperatures for selected snowcovered areas in the Sierra Nevada Mountains, derived from the daytime and nighttime printouts, show greater delta tau values for the sparsely vegetated higher elevations than for the lower elevation, more densely forested terrain. The differences for the 12 hour sequence are also greater in most instances than the 36 hour difference.

  16. Characteristics of African easterly waves associated with tropical cyclogenesis in the Cape Verde Islands region in July-August-September of 2004-2008

    NASA Astrophysics Data System (ADS)

    Arnault, Joël; Roux, Frank

    2011-04-01

    The most common synoptic-scale disturbances related to cyclogenesis over the tropical north Atlantic Ocean are African easterly waves (AEWs) that originated from the northern African continent. However, most of these waves do not evolve in tropical depressions, storms, or hurricanes. The reasons why only few AEWs develop and the necessary conditions for cyclogenetic evolution are still the subject of intense debate. Tropical cyclogenesis occurring near the Cape Verde Islands in the eastern tropical Atlantic is investigated here with five seasons (July-August-September of 2004-2008) of European Centre for Medium-Range Weather Forecasts analyses, Meteosat-9 images, and National Hurricane Center (National Oceanic and Atmospheric Administration, National Centers for Environmental Prediction) "best track" archives. The nine named storms that first reached tropical depression intensity east of 30°W, and two among six which developed between 30 and 40°W, during these five years evolved from intense AEW troughs, associated with low-level cyclonic circulation, weak mid-level anticyclonic Saharan flow to the east, and deep convection near the center of cyclonic vorticity. The cyclogenetic evolution of three AEW troughs, which verified these conditions but failed to develop into named storms, was probably inhibited by unusually dry environment and strong vertical wind shear. The fate of other AEW troughs, which did not satisfy the necessary conditions, is also discussed.

  17. The application of ERTS imagery to mapping snow cover in the western United States. [Salt Verde in Arizona and Sierra Nevada California

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.; Simmes, D. A.

    1974-01-01

    The author has identified the following significant results. In much of the western United States a large part of the utilized water comes from accumulated mountain snowpacks; thus, accurate measurements of snow distributions are required for input to streamflow prediction models. The application of ERTS-1 imagery for mapping snow has been evaluated for two geographic areas, the Salt-Verde watershed in central Arizona and the southern Sierra Nevada in California. Techniques have been developed to identify snow and to differentiate between snow and cloud. The snow extent for these two drainage areas has been mapped from the MSS-5 (0.6 - 0.7 microns) imagery and compared with aerial survey snow charts, aircraft photography, and ground-based snow measurements. The results indicate that ERTS imagery has substantial practical applications for snow mapping. Snow extent can be mapped from ERTS-1 imagery in more detail than is depicted on aerial survey snow charts. Moreover, in Arizona and southern California cloud obscuration does not appear to be a serious deterrent to the use of satellite data for snow survey. The costs involved in deriving snow maps from ERTS-1 imagery appear to be very reasonable in comparison with existing data collection methods.

  18. Chilled margin fragmentation as a trigger for transition from Strombolian to phreatomagmatic explosive activity at Cova de Paul Crater, Santo Antao, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Tarff, R. W.; Day, S. J.

    2013-07-01

    Sudden transitions from effusive or mildly explosive eruptions to violent phreatomagmatic explosive activity can occur at high-elevation vents on oceanic island volcanoes. Here, we describe near-vent deposits around the large Cova de Paul crater on Santo Antao, Cape Verde Islands, which provide insights into the transition from Strombolian magmatic to violently explosive phreatomagmatic activity during one such eruption. The Strombolian deposits change from welded spatter to bedded clinkery scoria to angular blocky scoria, and contain a distinct population of strongly banded, low-vesicularity angular sub-glassy clasts with strongly prolate vesicles. These sub-glassy clasts also form a discrete layer of larger blocks at the transition to the overlying phreatomagmatic deposits. They are compositionally identical to the Strombolian scoria and are interpreted to be fragments of flow-banded chilled margins from the walls of the eruptive conduit. The layer of large sub-glassy blocks records disintegration and expulsion of the chilled margins at the transition to phreatomagmatic activity. We interpret the sequence from spatter through clinkery scoria to blocky scoria as recording an increase in groundwater inflow into the conduit from pressurised aquifers, but at coolant input ratios below those required for explosions. The shattering of the chilled margins to produce the bed of large sub-glassy blocks appears to have allowed a much greater water flow into the conduit, leading to the phreatomagmatic explosive phase of the eruption.

  19. Tortricid Moths Reared from the Invasive Weed Mexican Palo Verde, Parkinsonia aculeata, with Comments on their Host Specificity, Biology, Geographic Distribution, and Systematics

    PubMed Central

    Brown, John W.; Segura, Ricardo; Santiago-Jiménez, Quiyari; Rota, Jadranka; Heard, Tim A.

    2011-01-01

    As part of efforts to identify native herbivores of Mexican palo verde, Parkinsonia aculeata L. (Leguminosae: Caesalpinioideae), as potential biological control agents against this invasive weed in Australia, ten species of Tortricidae (Lepidoptera) were reared from Guatemala, Mexico, Nicaragua, and Venezuela: Amorbia concavana (Zeller), Platynota rostrana (Walker), Platynota helianthes (Meyrick), Platynota stultana Walsingham (all Tortricinae: Sparganothini), Rudenia leguminana (Busck), Cochylis sp. (both Tortricinae: Cochylini), Ofatulena duodecemstriata (Walsingham), O. luminosa Heinrich, Ofatulena sp. (all Olethreutinae: Grapholitini), and Crocidosema lantana Busck (Olethreutinae: Eucosmini). Significant geographic range extensions are provided for O. duodecemstriata and R. leguminana. These are the first documented records of P. aculeata as a host plant for all but O. luminosa. The four species of Sparganothini are polyphagous; in contrast, the two Cochylini and three Grapholitini likely are specialists on Leguminosae. Ofatulena luminosa is possibly host specific on P. aculeata. Host trials with Rudenia leguminana also provide some evidence of specificity, in contrast to historical rearing records. To examine the possibility that R. leguminana is a complex of species, two data sets of molecular markers were examined: (1) a combined data set of two mitochondrial markers (a 781-basepair region of cytochrome c oxidase I (COI) and a 685-basepair region of cytochrome c oxidase II) and one nuclear marker (a 531-basepair region of the 28S domain 2); and (2) the 650-basepair “barcode” region of COI. Analyses of both data sets strongly suggest that individuals examined in this study belong to more than one species. PMID:21521138

  20. Epidemiological characterization of Plasmodium falciparum in the Republic of Cabo Verde: implications for potential large-scale re-emergence of malaria

    PubMed Central

    Alves, Joana; Roque, Ana Luísa; Cravo, Pedro; Valdez, Tomás; Jelinek, Tomas; do Rosário, Virgílio E; Arez, Ana Paula

    2006-01-01

    Background Malaria has come near eradication at archipelago of Cabo Verde in 1970. Infections are now only observed in Santiago, where outbreaks occur. In these islands, malaria is considered by the international community as being of limited risk and, therefore, no prophylaxis is recommended. Since the understanding of factors that determine malaria outbreaks are crucial for controlling the disease, the present study aimed to investigate if the malaria infections observed in Santiago Island are maintained in isolated foci and in asymptomatic individuals. Methods The occurrence of asymptomatic carriers in villages with history of malaria as well as the level of exposure of these populations were investigated using PCR and serological analyses. Results Results indicate that malaria is maintained as asymptomatic and sub-patent infections and that the majority of the circulating parasite populations harbour chloroquine-resistant mutations. Conclusion These observations highlight the alarming prospect of malaria to become a serious public health problem and underscore the need for a tighter surveillance. PMID:16630349

  1. An evaluation of sand and gravel resources in and near the Prescott National Forest in the Verde Valley, Arizona; with a section on evaluation of sand and gravel resources using selected engineering variables

    USGS Publications Warehouse

    Cox, Leslie J.; Bliss, James D.; Miller, Robert J.

    1999-01-01

    This study was based on available published literature. Although no field investigation was conducted in the Prescott National Forest to the west of the Verde River, a field investigation was conducted in the summer of 1994 by this author on the Coconino National Forest, to the east of the Verde River, where units of surficial materials of the same age and similar character are found (Cox, 1995). The intent of this evaluation of sand and gravel resources in the Prescott National Forest and adjacent areas in the Verde Valley, is to provide the land managers of the U.S. Forest Service with a map that delineates sand- and gravel-bearing geologic units. The map distinguishes (1) sand-and gravel-bearing units that are limited to channels from those that are not, (2) sand-and gravel-bearing units that are thin (generally less than 40 feet thick which is one contour interval on the topographic maps) from those that are locally thick (generally 40 feet or more), (3) sand- and gravel-bearing units that are poorly sorted from those that are well-sorted4, (4) sand- and gravel-bearing units that have little or no soil development from those that have greater degrees of soil development and lithification, (5) and sand- and gravel-bearing units that support riparian vegetation from those that do not. These distinctive characteristics are related to the geologic age or depositional setting of the rock materials and can be distinguished where areas are mapped in detail.

  2. In the footsteps of Darwin at Santiago (Cape Verde Island): new insights from a field reappraisal of the (white sedimentary layer)

    NASA Astrophysics Data System (ADS)

    Sarti, Giovanni; Bertocchini, Federico; Chiesura, Guido; Bini, Monica; Cascella, Antonio; Ribolini, Adriano; Patacca, Etta; Casacchia, Claudia

    2014-05-01

    The volcanic island of Santiago de Cape Verde was the first stop of Darwin during his circumnavigation on board of the Beagle vessel (1832). The exploration of Santiago played a fundamental role in the growth of his interest for geology. During the three weeks spent on the island, Darwin had the opportunity of doing many pioneering and insightful observations around the morphology and structure of the basaltic platforms. He was also very impressed by a white fossiliferous layer. This horizon, few meters thick, is sandwiched in between two black volcanic units and outcrops extensively along the coastal cliff in the southern part of Santiago. Darwin rightly identified the marine depositional origin of the white layer (Darwin's old beach) observing that the same fossilized shells and algae were still living in the beaches of the island. In 2008, 2009 and 2102 under the auspices of the scientific project "Darwin at Santiago de Cape Verde Island" three expeditions have been performed on the footsteps of Darwin. The firsts two missions have been focused on the mapping and characterization of the basaltic units while the third has exclusively dealt with the facies analysis of the white sedimentary layer. The main goal of this study is to revisit, by a modern sedimentological, stratigraphical, and geomorphological point of view, the white old beach sequence described by Darwin in 1832. The first results display a very complex and fascinating geological history, largely grasped by the observations of Darwin, driven by the interplay among volcanic, tectonic and sea level changes factors. The old beach sequence (likely Pleistocene in age) is composed of two main transgressive depositional units separated by an angular erosional unconformity. This is a first important new topic enriching the Darwin's observations. The unconformity is well exposed along the small Quail island cliff, located about 1 km seaward of the Praia harbour. The unconformity divides sandy fossil

  3. Coastal dunes with high content of rhodolith (coralline red algae) bioclasts: Pleistocene formations on Maio and São Nicolau in the Cape Verde archipelago

    NASA Astrophysics Data System (ADS)

    Johnson, Markes E.; Baarli, B. Gudveig; da Silva, Carlos M.; Cachão, Mário; Ramalho, Ricardo S.; Ledesma-Vázquez, Jorge; Mayoral, Eduardo J.; Santos, Ana

    2013-03-01

    Rhodoliths are spherical growths (coralline red algae) that contribute bioclasts to coastal dunes in the Gulf of California (Mexico) and the Canary Islands (North Atlantic). Pleistocene dunes on Maio and São Nicolau islands in the Cape Verde archipelago were studied to quantify rhodolith contribution relative to other sources. Near Pilão Cão on Maio, a transverse dune at Lomba Greija covers 0.3 km2, exposing stoss slopes that dip 8°-10° NE and leeward slip faces that dip 28°-32° SW and SE. Point counts on thin-section samples show that basalt and other non-carbonate materials account for 5%, on average, whereas fine matrix and voided space (dissolved grains) account for 67%. Among remaining identifiable bioclasts (coralline red algae, mollusks, corals, foraminifera, and echinoderms), rhodolith grains with an average diameter of 0.5 mm account for 74%. Near Carriçal at Covoadinha de Chacina on the SE coast of São Nicolau, the stoss slope dips 8° SE for 70-80 m on narrow longitudinal dunes. Point counts on a thin-section sample taken 2.5 m above basement rock, reveal that basalt and other non-carbonate materials account for 10%, on average, whereas fine matrix and voided spaces account for 60%. Among identifiable bioclasts from the remainder (coralline red algae, mollusks, echinoderms, and bryozoa), rhodolith grains ranging in size from 0.5 to 1 mm account for 96%. Potential enrichment from coralline red algae may be overlooked in coastal dunes, because content normally is described as dominated by mollusk shells, the tests from abundant foraminifera, and/or ooids.

  4. Assessment of imposex and butyltin concentrations in Gemophos viverratus (Kiener, 1834), from São Vicente, Republic of Cabo Verde (Africa).

    PubMed

    Lopes-Dos-Santos, R M A; Galante-Oliveira, S; Lopes, E; Almeida, C; Barroso, C

    2014-09-01

    This work constitutes the first assessment of tributyltin (TBT) pollution levels in the Republic of Cabo Verde (Africa) and proposes the marine gastropod Gemophos viverratus (Kiener, 1834) as a new bioindicator of TBT pollution in the Macaronesia and west coast of Africa. Specimens were collected between August and October 2012 along a gradient of naval traffic in São Vicente Island. The results clearly indicate an increase of imposex levels (percentage of females affected with imposex, 0-100 %; vas deferens sequence index, 0-4.1; relative penis length index, 0-54.6 %) and female TBT contamination (from 5 to 37 ngSn g(-1) dry weight (dw)) from outside to inside the harbour of Porto Grande Bay and identify this area as the focus of TBT pollution in the island. The butyltin degradation index for G. viverratus tissues ranged between 1.3 and 2.2, which being above 1 suggests that a considerable part of TBT inputs to the bay may not be very recent. Sterile females were found inside the harbour with an incidence up to 21.4 %. Considering the existence of a planktonic veliger stage in the life cycle of G. viverratus, it is expected that recruitment of newborn individuals can be supplied from unaffected breeding females inside and outside the Porto Grande Bay, resulting in a reduced impact of TBT pollution on population abundance. G. viverratus is very promising to be used as a simple, inexpensive and efficient novel tool for TBT pollution biomonitoring in the Macaronesia and west coast of Africa, a region for which there is an astonishing lack of information concerning levels and ecological impacts of TBT pollution. PMID:24878557

  5. Assessment of 1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene (DDE) Transformation Rates on the Palos Verdes Shelf, CA

    USGS Publications Warehouse

    Eganhouse, Robert P.; Pontolillo, James

    2008-01-01

    In 1953, the world's largest producer of DDT, Montrose Chemical Corporation, began to discharge process wastes into sewers of the Los Angeles County Sanitation Districts (LACSD), California. By 1971, when the sewer connection was terminated, approximately 1,500-2,000 metric tons of DDT had been introduced to the LACSD treatment plant in Carson, CA. After treatment, effluent from this plant was released to the ocean through a submarine outfall system on the Palos Verdes Shelf (PVS) near Los Angeles, resulting in the accumulation of highly contaminated marine sediments. Numerous investigations of the PVS have been undertaken since the late 1960s, but few have focused on the biogeochemical fate of DDT and its transformation products. In the early 1990s, it was shown that DDE, the major DDT compound in the sediments, was being reductively dechlorinated by microorganisms resident in sediments on the PVS. The U.S. Geological Survey undertook a study in cooperation with the U.S. Environmental Protection Agency to provide a better understanding of the range of reductive dechlorination rates on the PVS and the environmental factors that control them. Existing data show that rates of reductive dechlorination are variable spatially. A comparison of data from two cores collected approximately 7 kilometers downcurrent from the outfall systems in 1992 and 2003 yielded an average first-order transformation rate of approximately 0.05 yr-1. A multistep reaction model suggests that inventories of DDE in PVS sediments at the study site will continue to decline, whereas the inventory of the metabolite DDNU will reach a maximum around 2014.

  6. Evaluation of a main steam line break with induced, multiple tube ruptures: A comparison of NUREG 1477 (Draft) and transient methodologies Palo Verde Nuclear Generating Station

    SciTech Connect

    Parrish, K.R.

    1995-09-01

    This paper presents the approach taken to analyze the radiological consequences of a postulated main steam line break event, with one or more tube ruptures, for the Palo Verde Nuclear Generating Station. The analysis was required to support the restart of PVNGS Unit 2 following the steam generator tube rupture event on March 14, 1993 and to justify continued operation of Units 1 and 3. During the post-event evaluation, the NRC expressed concern that Unit 2 could have been operating with degraded tubes and that similar conditions could exist in Units 1 and 3. The NRC therefore directed that a safety assessment be performed to evaluate a worst case scenario in which a non-isolable main steam line break occurs inducing one or more tube failures in the faulted steam generator. This assessment was to use the generic approach described in NUREG 1477, Voltage-Based Interim Plugging Criteria for Steam Generator Tubes - Task Group Report. An analysis based on the NUREG approach was performed but produced unacceptable results for off-site and control room thyroid doses. The NUREG methodology, however, does not account for plant thermal-hydraulic transient effects, system performance, or operator actions which could be credited to mitigate dose consequences. To deal with these issues, a more detailed analysis methodology was developed using a modified version of the Combustion Engineering Plant Analysis Code, which examines the dose consequences for a main steam line break transient with induced tube failures for a spectrum equivalent to 1 to 4 double ended guillotine U-tube breaks. By incorporating transient plant system responses and operator actions, the analysis demonstrates that the off-site and control room does consequences for a MSLBGTR can be reduced to acceptable limits. This analysis, in combination with other corrective and recovery actions, provided sufficient justification for continued operation of PVNGS Units 1 and 3, and for the subsequent restart of Unit 2.

  7. Simulated effects of groundwater pumping and artificial recharge on surface-water resources and riparian vegetation in the Verde Valley sub-basin, Central Arizona

    USGS Publications Warehouse

    Leake, Stanley A.; Pool, Donald R.

    2010-01-01

    In the Verde Valley sub-basin, groundwater use has increased in recent decades. Residents and stakeholders in the area have established several groups to help in planning for sustainability of water and other resources of the area. One of the issues of concern is the effect of groundwater pumping in the sub-basin on surface water and on groundwater-dependent riparian vegetation. The Northern Arizona Regional Groundwater-Flow Model by Pool and others (in press) is the most comprehensive and up-to-date tool available to understand the effects of groundwater pumping in the sub-basin. Using a procedure by Leake and others (2008), this model was modified and used to calculate effects of groundwater pumping on surface-water flow and evapotranspiration for areas in the sub-basin. This report presents results for the upper two model layers for pumping durations of 10 and 50 years. Results are in the form of maps that indicate the fraction of the well pumping rate that can be accounted for as the combined effect of reduced surface-water flow and evapotranspiration. In general, the highest and most rapid responses to pumping were computed to occur near surface-water features simulated in the modified model, but results are not uniform along these features. The results are intended to indicate general patterns of model-computed response over large areas. For site-specific projects, improved results may require detailed studies of the local hydrologic conditions and a refinement of the modified model in the area of interest.

  8. The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys

    USGS Publications Warehouse

    Brothers, Daniel S.; Conrad, James E.; Maier, Katherine L.; Paull, Charles K.; McGann, Mary L.; Caress, David W.

    2015-01-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17–24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3–2.8 mm/yr and provide a best estimate of 1.6–1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20–30% of the total right-lateral slip budget accommodated offshore Southern California.

  9. The Palos Verdes Fault offshore Southern California: Late Pleistocene to present tectonic geomorphology, seascape evolution, and slip rate estimate based on AUV and ROV surveys

    NASA Astrophysics Data System (ADS)

    Brothers, Daniel S.; Conrad, James E.; Maier, Katherine L.; Paull, Charles K.; McGann, Mary; Caress, David W.

    2015-07-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17-24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3-2.8 mm/yr and provide a best estimate of 1.6-1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20-30% of the total right-lateral slip budget accommodated offshore Southern California.

  10. Frequency of the CCR5-delta32 mutation in the Atlantic island populations of Madeira, the Azores, Cabo Verde, and São Tomé e Príncipe.

    PubMed

    Freitas, Tamira; Brehm, António; Fernandes, Ana Teresa

    2006-12-01

    There is evidence that the CCR5-delta32 mutation confers protection against HIV-1 infection to homozygous individuals. It is believed that this mutation spread through Europe with the Vikings and that it has been subjected to positive selection, leading to a high frequency in Europe (approximately 10%). We carried out the present study to determine the 32-bp deletion allele and genotype frequencies of the CCR5 gene (CCR5-delta32) in the Atlantic island populations of Madeira, the Azores, Cabo Verde, and São Tomé e Principe. These Atlantic archipelagos were all colonized by the Portuguese in the 15th and 16th centuries, but the latter two received most of their settlers from the West African coast. The frequency of the CCR5-delta32 mutation varies between 0% in São Tomé e Príncipe and 16.5% in the Azores. The Azores Islands have one of the highest frequencies of homozygotes found in Europe (4.8%). There are significant differences (P < 0.05) between some of these populations, for example, between São Tomé e Príncipe and Cabo Verde, and even within populations (e.g., Portugal, Madeira, and the Azores). PMID:17564248

  11. A comparison of estimates of basin-scale soil-moisture evapotranspiration and estimates of riparian groundwater evapotranspiration with implications for water budgets in the Verde Valley, Central Arizona, USA

    USGS Publications Warehouse

    Tillman, Fred; Wiele, Stephen M.; Pool, Donald R.

    2015-01-01

    Population growth in the Verde Valley in Arizona has led to efforts to better understand water availability in the watershed. Evapotranspiration (ET) is a substantial component of the water budget and a critical factor in estimating groundwater recharge in the area. In this study, four estimates of ET are compared and discussed with applications to the Verde Valley. Higher potential ET (PET) rates from the soil-water balance (SWB) recharge model resulted in an average annual ET volume about 17% greater than for ET from the basin characteristics (BCM) recharge model. Annual BCM PET volume, however, was greater by about a factor of 2 or more than SWB actual ET (AET) estimates, which are used in the SWB model to estimate groundwater recharge. ET also was estimated using a method that combines MODIS-EVI remote sensing data and geospatial information and by the MODFLOW-EVT ET package as part of a regional groundwater-flow model that includes the study area. Annual ET volumes were about same for upper-bound MODIS-EVI ET for perennial streams as for the MODFLOW ET estimates, with the small differences between the two methods having minimal impact on annual or longer groundwater budgets for the study area.

  12. Trophic transfer and effects of DDT in male hornyhead turbot (Pleuronichthys verticalis) from Palos Verdes Superfund site, CA (USA) and comparisons to field monitoring.

    PubMed

    Crago, Jordan; Xu, Elvis Genbo; Kupsco, Allison; Jia, Fang; Mehinto, Alvine C; Lao, Wenjian; Maruya, Keith A; Gan, Jay; Schlenk, Daniel

    2016-06-01

    High concentrations of DDT and metabolites (ΣDDT) have been detected in sediment and the demersal flatfish hornyhead turbot (Pleuronichtys verticalis) collected from Palos Verdes (PV), California, USA, a site contaminated with over 100 metric tons of DDT throughout 1960s-70s. This study was conducted to assess the transfer of ΣDDT from PV-sediment into polychaetes (Neanthes arenaceodentata) and hornyhead turbot, and to investigate if the responses in turbots from two different laboratory exposures mimic those in turbots caught in PV (PV-turbot). Turbot fed PV-sediment-contaminated polychaete for 7 days had liver concentrations of ΣDDT similar to PV-turbot. After 28 days, ΣDDT also accumulated in livers of turbot gavaged with a ΣDDT mixture. In vitro cell bioassays indicated significant increases of 17β-estradiol equivalents (EEQ) in turbot bile extracts as compared to the control in the 7-day study. These responses corresponded to those measured in PV-fish. Glucocorticoid receptor (GR), anti-androgen receptor (anti-AR), estrogen receptor (ER) or aryl hydrocarbon receptor (AhR) activities were also observed in extracts of PV-sediment, and PV-sediment-exposed worm. Anti-AR, AhR and GR activities were significantly higher in PV-sediment than reference sediment (San Diego, SD). Higher transcripts of hepatic VTG, ERα and ERβ were found in PV-turbot than SD-turbot, but were unaltered in fish exposed to sediment-contaminated worms for the 7-day study. In contrast, liver extracts from the 28-day treatment of ΣDDT showed lower EEQ but similar hepatic VTG and ERβ transcripts relative to those of PV-turbot. These data indicated that trophic transfer of sediment-associated DDT in 7-day exposures corresponded to field measurements of DDT residues and in vitro ER bioactivities, but failed to mimic in vivo biological effects observed in field fish. In contrast, treatment with ΣDDT alone for 28 days mimicked in vivo biological effects of DDTs in PV fish, but did not

  13. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands

    PubMed Central

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  14. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands.

    PubMed

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  15. Integrated Tactical Monitoring of the 2014-2015 Eruption of Pico of Fogo, Cape Verde, by Spaceborne and Ground-based observations.

    NASA Astrophysics Data System (ADS)

    Ferrucci, F.; Day, S. J.; Faria, B. V. E.

    2015-12-01

    The 2014-2015 eruption of Pico of Fogo (Cape Verde), which totaled about 12 million cubic meters in two months, was monitored in real- and near-realtime by ground based and spaceborne instruments, respectively. Volcanic tremor amplitude (RSAM) above the background noise was first detected at seismic stations located at the foot of the Pico cone, about 08 UTC on November 23, 2014. A short-lasting, pre-eruptive tremor burst ca. 09:45 UTC forerun by about 1.5 hours the syn-eruptive tremor, which started between 11:12-11:15 UTC and was taken as the most reliable marker of the eruption onset. Spaceborne observation of MIR-TIR radiances with 15-minute refresh by payload SEVIRI onboard geostationary Meteosat-10, orbiting at 0°N-0°E over the Gulf of Guinea, pointed to a slightly later onset (11:15-11:30). Initial, radiant flux derived effusion rates were in the order of 16± 4 m3/s, with an isolated peak of 27 ± 8 m3/s reached on November 27, then slowly declined. RSAM and effusion rate series kept fairly well correlated in time, with tremor amplitude variations slightly ahead of radiance changes all the time. While villages located 1700m a.s.l. at the foot of Pico were largely destroyed by the early December, continued advance of lavas led to concern that the main flow could escape the summit caldera and propagate downslope to the northeast, threatening urban areas. Near-realtime monitoring of effusion rates became crucial to compute limiting flow lengths, and to assess that rates and volumes were not sufficient to sustain lava flow escapes. The 20 m3/s alert threshold was not approached anymore after December 9. Geophysical markers of sharply declined activity after mid-December, and until the end of eruption on February 7, 2015, could be constrained only by moderate-to-high spatial resolution data with multispectral pixel footprints between 106 m2 (MODIS) and 900 m2 (Landsat-8 OLI and EO-1 ALI)

  16. Generalized hydrogeology and ground-water budget for the C Aquifer, Little Colorado River Basin and parts of the Verde and Salt River Basins, Arizona and New Mexico

    USGS Publications Warehouse

    Hart, Robert J.; Ward, John J.; Bills, Donald J.; Flynn, Marilyn E.

    2002-01-01

    The C aquifer underlies the Little Colorado River Basin and parts of the Verde and Salt River Basins and is named for the primary water-bearing rock unit of the aquifer, the Coconino Sandstone. The areal extent of this aquifer is more than 27,000 square miles. More than 1,000 well and spring sites were identified in the U.S. Geological Survey database for the C aquifer in Arizona and New Mexico. The C aquifer is the most productive aquifer in the Little Colorado River Basin. The Little Colorado River is the primary surface-water feature in the area, and it has a direct hydraulic connection with the C aquifer in some areas. Spring discharge as base flow from the C aquifer occurs predominantly in the lower 13 miles of the Little Colorado River subsequent to downward leakage into the deeper Redwall-Muav Limestone aquifer. Ground-water mounds or divides exist along the southern and northeastern boundaries of the Little Colorado River Basin. The ground-water divides are significant boundaries of the C aquifer; however, the location and persistence of the divides potentially can be affected by ground-water withdrawals. Ground-water development in the C aquifer has increased steadily since the 1940s because population growth has produced an increased need for agricultural, industrial, and public water supply. Ground-water pumpage from the C aquifer during 1995 was about 140,000 acre-feet. Ground-water budget components for the C aquifer were evaluated using measured or estimated discharge values. The system was assumed to be in a steady-state condition with respect to natural recharge and discharge, and the stability of discharge from major springs during the past several decades supported the steady-state assumption. Downward leakage to the Redwall-Muav Limestone aquifer is a major discharge component for the ground-water budget. Discharge from the C aquifer is estimated to be 319,000 acre-feet per year.

  17. Potential depletion of surface water in the Colorado River and agricultural drains by groundwater pumping in the Parker-Palo Verde-Cibola area, Arizona and California

    USGS Publications Warehouse

    Leake, Stanley A.; Owen-Joyce, Sandra J.; Heilman, Julian A.

    2013-01-01

    Water use along the lower Colorado River is allocated as “consumptive use,” which is defined to be the amount of water diverted from the river minus the amount that returns to the river. Diversions of water from the river include surface water in canals and water removed from the river by pumping wells in the aquifer connected to the river. A complication in accounting for water pumped by wells occurs if the pumping depletes water in drains and reduces measured return flow in those drains. In that case, consumptive use of water pumped by the wells is accounted for in the reduction of measured return flow. A method is needed to understand where groundwater pumping will deplete water in the river and where it will deplete water in drains. To provide a basis for future accounting for pumped groundwater in the Parker-Palo Verde-Cibola area, a superposition model was constructed. The model consists of three layers of finite-difference cells that cover most of the aquifer in the study area. The model was run repeatedly with each run having a pumping well in a different model cell. The source of pumped water that is depletion of the river, expressed as a fraction of the pumping rate, was computed for all active cells in model layer 1, and maps were constructed to understand where groundwater pumping depletes the river and where it depletes drains. The model results indicate that if one or more drains exist between a pumping well location and the river, nearly all of the depletion will be from drains, and little or no depletion will come from the Colorado River. Results also show that if a well pumps on a side of the river with no drains in the immediate area, depletion will come from the Colorado River. Finally, if a well pumps between the river and drains that parallel the river, a fraction of the pumping will come from the river and the rest will come from the drains. Model results presented in this report may be considered in development or refinement of strategies

  18. Somewhere over the Verde Rainbow

    ERIC Educational Resources Information Center

    Ekart, Donna F.

    2008-01-01

    When the electronic resource management system (ERM) at Kansas State University Libraries suffered a horrible data loss, the "contract db" presented a challenge for the librarians responsible for electronic resources. It was a decent data repository, but it had no ability to manage the tangled process of licensing, acquiring, activating, using,…

  19. Precursory signals of the 2014-15 Fogo eruption (Cape Verde) detected by surface CO2 emission and heat flow observations

    NASA Astrophysics Data System (ADS)

    Pérez, Nemesio M.; Dionis, Samara; Fernandes, Paulo; Barrancos, José; Rodríguez, Fátima; Bandomo, Zuleyka; Hernández, Pedro A.; Melián, Gladys V.; Silva, Sónia; Padilla, Germán; Padrón, Eleazar; Cabral, Jeremias; Calvo, David; Asensio-Ramos, María; Pereira, José Manuel; Gonçalves, António A.; Barros, Inocencio; Semedo, Helio

    2015-04-01

    On November 23, 2014 a new eruption occurred at Fogo volcano (Cape Verde) after 19 years of the last eruptive event in 1995. In the case of the 1995 Fogo eruption, a volcano monitoring program for the volcanic surveillance of Fogo did not exist. On the contrary, a simple and multidisciplinary volcano monitoring program was initiated since 2007 to detect early warning signals of a new volcanic unrest such as the 2014-15 Fogo eruption. Diffuse CO2 emission surveys at the summit crater of Pico do Fogo volcano were periodically carried out from May 2007 to October 2014 to provide this multidisciplinary approach and to monitor potential volcanic activity changes. During this 7 year period, CO2 efflux ranged from non detectable (< 1.5 g m-2 d-1) up to relatively high (61.9 kg m-2 d-1) values. The observed average δ13C- CO2 values related to these diffuse CO2 emission surveys ranged from -22.1 to 1.6 ‰, and surface heat flux measurements, following the method of Dawson (1964), showed also a wide range of values from 0.1 to 460 W m-2. Areas with the highest observed CO2 efflux values were also characterized by a relatively high soil temperature and an intense surface hydrothermal alteration, which supports that degassing process is primary controlled by an advective mechanism generated by geothermal gradients (convection). Two periods of anomalous diffuse CO2 emission were observed between February 2009 to February 2010 and March to August 2014, respectively. Rest of surveys showed the lowest variability on diffuse CO2 emission, ranging from 23 to 186 t d-1 (average = 86 t d-1). The first anomalous period was characterized by a sharp increase on diffuse CO2 emission, suggesting the first magma intrusion beneath Pico do Fogo volcano. This observation is also supported by a significant change on the δ13C- CO2 signature from May 2009 (-10.2 ‰) to February 2010 (-6.1‰) of the diffuse CO2 degassing, indicating an enrichment on the magmatic CO2 component. On February

  20. Insights from geophysical monitoring into the volcano structure and magma supply systems at three very different oceanic islands in the Cape Verde archipelago

    NASA Astrophysics Data System (ADS)

    Faria, B. V.; Day, S.; Fonseca, J. F.

    2013-12-01

    Three oceanic volcano islands in the west of the Cape Verde archipelago are considered to have the highest levels of volcanic hazard in the archipelago: Fogo, Brava, and Santo Antao. Fogo has had frequent mainly effusive eruptions in historic time, the most recent in 1995, whilst Brava and Santo Antao have ongoing geothermal activity and felt earthquakes, and have experienced geologically recent violent explosive eruptions. Therefore, these three islands have been the focus of recent efforts to set up seismic networks to monitor their activity. Here we present the first results from these networks, and propose interpretations of the monitored seismic activity in terms of subsurface volcano structures, near-surface intrusive activity and seasonal controls on geothermal activity. In Fogo, most recorded seismic events are hydrothermal events. These show a strong seasonal variation, increasing during the summer rain season and decreasing afterwards. Rare volcano-tectonic (VT) events (0.1

  1. Diffuse Hydrogen (H2) emissions from the summit crater of Pico do Fogo before the 2014-15 eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Dionis, Samara; Padrón, Eleazar; Melián, Gladys V.; Asensio-Ramos, María; Fernandes, Paulo; Barrancos, José; Rodríguez, Fátima; Padilla, Germán; Calvo, David; Hernández, Pedro A.; Silva, Sónia; Cabral, Jeremias; Bandomo, Zuleyka; Pereira, José Manuel; Semedo, Helio; Pérez, Nemesio M.

    2015-04-01

    Pico do Fogo is an active stratovolcano rising 2,829 m above sea level, situated in Fogo Island (476 km2), Cape Verde. Pico do Fogo has a long eruptive history with about 30 eruptions since its discovery (~1500 AD). On November 23, 2014 a new volcanic eruption started at the southwestern flank of the volcano after 19 years of the last eruptive event on 1995. Diffuse hydrogen (H2) emission from the summit crater of Pico do Fogo has been regularly estimated since 2007 to improve the geochemical monitoring program for the volcano surveillance. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the volcano-hydrothermal reservoir. Because of its chemical and physical characteristics, H2 moves rapidly though the crust and escapes to the atmosphere. These characteristics make H2 an excellent tracer for processes that occurs in the volcano-hydrothermal systems. The first published data on diffuse H2 degassing rate from Pico do Fogo volcano (37.3 ± 11.3 kg d-1) is related to a field work performed on February 2010 (Dionis et al., 2015). A total of seven diffuse H2 degassing surveys have been carried out during the period 2007-2014. Soil gas H2 concentration measured at 40 cm depth, allowed the computation of its emission rate in about 50 sampling sites selected in the surface environment of Pico do Fogo summit crater (0.14 km2). Both advective (convective) and diffuse components were estimated. The sampling sites were selected to cover homogeneously the study area, allowing the computation of the total H2 emission by sequential Gaussian simulation (sGs). During the study period diffuse H2 emission rate ranged between 2.9 and 163.6 kg d-1. On February 2010, it was observed the first relatively high diffuse H2 emission value which suggests the occurrence of an increase in the heat flow. However, higher observed diffuse H2 emission values than February 2010 were detected on April 2013 (75

  2. Geophysical analysis of the Salmon Peak Formation near Amistad Reservoir Dam, Val Verde County, Texas, and Coahuila, Mexico, March 2006, to aid in piezometer placement

    USGS Publications Warehouse

    Stanton, Gregory P.; Kress, Wade H.; Teeple, Andrew P.; Greenslate, Michael L.; Clark, Allan K.

    2007-01-01

    Since 1992, numerous sinkholes have developed northwest of the Amistad Reservoir dam on the Rio Grande. Increases in the discharge of springs south of the dam, on the western side of the Rio Grande, in Coahuila, Mexico, have been documented. In 1995 the Mexico Section of the International Boundary and Water Commission (IBWC) completed a study of the western embankment (Coahuila, Mexico) of the dam that included surface geophysics, borehole geophysics, and installation of piezometers to learn more about subsurface conditions. As part of a 5-year safety inspection in 2005, technical advisors recommended that one line of similarly constructed piezometers be installed on the eastern embankment (Val Verde County, Texas) of the dam for comparison of water levels (potentiometric head) on both the western and eastern embankments of Amistad Reservoir dam. To provide technical assistance for the horizontal and vertical placement of piezometers on the eastern embankment of Amistad Reservoir dam, the U.S. Geological Survey, in cooperation with the U.S. Section of the IBWC, conducted a study along both the western and eastern embankments of Amistad Reservoir dam. The study involved an integrated approach using surface and borehole geophysical methods. In the western embankment investigation, geological and geophysical characteristics that indicate relatively large water-yielding properties of the Salmon Peak Formation were identified. The direct-current (DC) resistivity method was selected as the surface geophysical reconnaissance technique to correlate relatively large water-yielding properties of the Salmon Peak Formation, identified from analysis of borehole geophysical logs, with variations in subsurface resistivity. The dipole-dipole array and the reciprocal Schlumberger array were selected as the most applicable DC resistivity arrays. Two resistivity units were identified in both the dipole-dipole array data and the reciprocal Schlumberger array data along DC resistivity

  3. Presentation of the Multimédia Game "Geolover" Concept, to Educational Enchancement of the Geolocical Heritage of the Following Regions: "Ilha do Fogo" (Cabo-Verde), Seridó (Brasil), Sabugal (Portugal) and Açores (Portugal)

    NASA Astrophysics Data System (ADS)

    Cabral, João; Gomes, Ana; Alfama, Vera; Oliveira, Sirlene; Pinharandas, Carlos; Fonseca, Pedro; Campos, José; Nobre, José

    2013-04-01

    "Geolover" - Presentation of the multimédia game concept, to educational enchancement of the geolocical heritage of the following regions: : "Ilha do Fogo" (Cabo-Verde), Seridó (Brasil), Sabugal and Açores (Portugal). "Geolover" is a multitouch game, played by four players simultaneously, identified by 4 mascots and using as sceneries, the four regions landscapes, aimed to the young people with ages between 8 and 12 years old. The main objective is value the geological heritage of the Ilha do Fogo (Cabo Verde), Seridó in State of Rio Grande do Norte (Brasil) , Sabugal in Beira Alta province (Portugal) and Arquipélago dos Açores (Portuguese autonomous region). These regions have a great geological heritage like volcanology, plutonic rocks, sedimentar formations, metamorphic, paleontologic, mineralogic, geomorphologic, hydric and mining resources. Such heritage is being used in the different regions has base of studies to senior scientists and were used to great scientific researches. The diversified and distinguished cultural heritage of these four regions is referenced and it's a value to the union of the students from these three continents, with the Portuguese language as communication tool. The variety of the geological wealth and cultural of these regions, results in the common objective of their valuing like Geoparks. His creation on these three regions is a strategy with a great relevance to the socio-economic development. With the creation of this game, we promote the union of these 3 countries from these three continents, the universal values of the heritage richness that are offered by our planet.

  4. Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 3. Unit RL-10 turbine generator condition assessment report and units RL-10 and RL-11 boiler feed pump conditon assessment report. Export trade information

    SciTech Connect

    Not Available

    1991-03-28

    The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the last of three volumes and it is divided into the following sections: (1) Condition Assessment of Unit RL-10 Turbine-Generator; (2) Condition Assessment of Unit RL-10 and RL-11 Boiler Feed Pumps.

  5. SRTM Anaglyph: Laguna Mellquina, Andes Mountains, Argentina

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This anaglyph of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM) view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters (2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.

    This anaglyph was produced by first shading a preliminary SRTM elevation model. 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 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 was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM 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 the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), 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: 55.0 x 37.2 kilometers (34.1 x 23.1 miles) Location: 40.4 deg. South lat., 71.3 deg. West lon. Orientation: North toward the top Image Data: Shaded SRTM elevation model Date Acquired: February 2000

  6. Evaluation of baseline ground-water conditions in the Mosteiros, Ribeira Paul, and Ribeira Faja Basins, Republic of Cape Verde, West Africa, 2005-06

    USGS Publications Warehouse

    Heilweil, Victor M.; Earle, John D.; Cederberg, Jay R.; Messer, Mickey M.; Jorgensen, Brent E.; Verstraeten, Ingrid M.; Moura, Miguel A.; Querido, Arrigo; Spencer; Osorio, Tatiana

    2006-01-01

    This report documents current (2005-06) baseline ground-water conditions in three basins within the West African Republic of Cape Verde (Mosteiros on Fogo, Ribeira Paul on Santo Ant?o, and Ribeira Faj? on S?o Nicolau) based on existing data and additional data collected during this study. Ground-water conditions (indicators) include ground-water levels, ground-water recharge altitude, ground-water discharge amounts, ground-water age (residence time), and ground-water quality. These indicators are needed to evaluate (1) long-term changes in ground-water resources or water quality caused by planned ground-water development associated with agricultural projects in these basins, and (2) the feasibility of artificial recharge as a mitigation strategy to offset the potentially declining water levels associated with increased ground-water development. Ground-water levels in all three basins vary from less than a few meters to more than 170 meters below land surface. Continuous recorder and electric tape measurements at three monitoring wells (one per basin) showed variations between August 2005 and June 2006 of as much as 1.8 meters. Few historical water-level data were available for the Mosteiros or Ribeira Paul Basins. Historical records from Ribeira Faj? indicate very large ground-water declines during the 1980s and early 1990s, associated with dewatering of the Galleria Faj? tunnel. More-recent data indicate that ground-water levels in Ribeira Faj? have reached a new equilibrium, remaining fairly constant since the late 1990s. Because of the scarcity of observation wells within each basin, water-level data were combined with other techniques to evaluate ground-water conditions. These techniques include the quantification of ground-water discharge (well withdrawals, spring discharge, seepage to springs, and gallery drainage), field water-quality measurements, and the use of environmental tracers to evaluate sources of aquifer recharge, flow paths, and ground

  7. El rol de Ia colaboracion y el Modelo de Aprendizaje Basado en Proyectos (ABPr) mediante el lente de la Teoria de Actividad (CHAT): un estudio de caso con estudiantes de 9no grado

    NASA Astrophysics Data System (ADS)

    Delgado, Isabel C.

    Los modelos de eensenanza y aprendizaje constructivistas conceptualizan el aprendizaje como un proceso activo. El modelo de Aprendizaje Basado en Proyectos (ABPr) se distingue por una serie de componentes, entre los cuales se destaca el aspecto colaborativo y cooperativo como un reto al momento de su implantacion. Son pocas las investigaciones que se concentran en este aspecto del modelo. En este estudio, se analizaron las diversas interacciones que surgen durante la implantacion de una unidad curricular sobre el tema de Geologia de Puerto Rico, la cual se diseno con el modelo ABPr cuyo enfoque es orientacion a proyectos. Particularmente, se examinaron las interacciones sociales que surgen entre los pares y entre pares y docente durante el proceso de planificacion y desarrollo de los productos finales, al igual que las interacciones entre los estudiantes y el material didactico en estas etapas del modelo. La investigacion es de tipo cualitativo e incorpora como diseno el estudio de caso. Las diversas interacciones constituyen la unidad de analisis. En el estudio participaron 19 estudiantes de 9no grado, a quienes se organizaron en 5 grupos colaborativos por temas de interes (Pangea, Placas tectonicas, Volcanes, Tsunamis y Terremotos). Las tecnicas que se utilizaron para recopilar los datos fueron: observaciones participativas, grupos focales y analisis de documentos (cuadernos reflexivos y respuestas de los estudiantes a la pregunta central del proyecto). Para el analisis de los datos se aplico la teoria de actividad (CHAT) que concentra la unidad de analisis en la actividad humana en un contexto particular. Los resultados del estudio senalan que las interacciones entre pares, entre pares y docente, asi como entre estudiantes y material didactico son fundamentales en el proceso de aprendizaje. Una mayor interaccion entre pares durante las etapas de planificar y desarrollar los productos finales de la unidad, promueve una mejor comprension de los conceptos de la

  8. Chemical quality of sediment cores from the Laguna Madre, Laguna Atascosa and Arroyo Colorado, Texas

    USGS Publications Warehouse

    Van Metre, Peter C.

    1999-01-01

    Many contaminants introduced into the environment by human activities are hydrophobic, meaning they are relatively insoluble in water and, thus, are associated primarily with sediments. These contaminants include the organochlorine pesticides DOT and chlordane, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from industrial facilities and urban areas, and heavy metals such as arsenic, lead, mercury, and zinc. Understanding the occurrence of these contaminants in the environment requires sampling the sediments where the contaminants might be detected.

  9. The Santa Terezinha-Campos Verdes emerald district, central Brazil: structural and Sm-Nd data to constrain the tectonic evolution of the Neoproterozoic Brası´lia belt

    NASA Astrophysics Data System (ADS)

    D'el-Rey Silva, Luiz José Homem; Barros Neto, Leonel de Souza

    2002-12-01

    Structural analysis coupled with Sm-Nd isotope data and a detailed description of the geology of the Santa Terezinha-Campos Verdes emerald district (Goiás State, Central Brazil) constrain the evolution of the Neoproterozoic Brası´lia belt. The area is composed of tectonic slices of Archean-Paleoproterozoic gneiss, a Meso-Neoproterozoic metavolcanic sedimentary sequence called the Santa Terezinha sequence, and crustal-derived intrusive rocks such as mylonitic (ortho)gneiss and a syntectonic porphyry granite. It underwent a Neoproterozoic greenschist facies polyphase ductile deformation (D 1-D 3). Structures indicate an event of rotational deformation along a typical frontal ramp dipping gently to the west (i.e. an event of simple shear with top to ESE relative regional movement due to a subhorizontal WNW-ESE compression). A Sm-Nd whole-rock isochron age of 577±77 Ma for the intrusive rocks constrains the timing of at least part of the deformation/metamorphism in the area. Primary and metamorphic planar structures (mainly D 1-D 2) strike SW-NE and dip at low to moderate angles to the NW in the northern part of the area. However, they gradually rotate to SSE in the central SE part, where the Peixe River synclinorium is developed. This synclinorium is also the nest of the D 2 sheath folds that control emerald ore shoots. The Santa Cruz dome is a basement-cored, major elliptic structure in the SW of the area. The Santa Terezinha sequence represents a back-arc basin that received input from the Neoproterozoic Goiás magmatic arc to the west and the São Francisco ancient continental margin to the east. The basal and upper sections of this sequence correlate, respectively, with other passive margin and back-arc sequences of the Brası´lia belt.

  10. Seismic, side-scan survey, diving, and coring data analyzed by a Macintosh II sup TM computer and inexpensive software provide answers to a possible offshore extension of landslides at Palos Verdes Peninsula, California

    SciTech Connect

    Dill, R.F. ); Slosson, J.E. ); McEachen, D.B. )

    1990-05-01

    A Macintosh II{sup TM} computer and commercially available software were used to analyze and depict the topography, construct an isopach sediment thickness map, plot core positions, and locate the geology of an offshore area facing an active landslide on the southern side of Palos Verdes Peninsula California. Profile data from side scan sonar, 3.5 kHz, and Boomer subbottom, high-resolution seismic, diving, echo sounder traverses, and cores - all controlled with a mini Ranger II navigation system - were placed in MacGridzo{sup TM} and WingZ{sup TM} software programs. The computer-plotted data from seven sources were used to construct maps with overlays for evaluating the possibility of a shoreside landslide extending offshore. The poster session describes the offshore survey system and demonstrates the development of the computer data base, its placement into the MacGridzo{sup TM} gridding program, and transfer of gridded navigational locations to the WingZ{sup TM} data base and graphics program. Data will be manipulated to show how sea-floor features are enhanced and how isopach data were used to interpret the possibility of landslide displacement and Holocene sea level rise. The software permits rapid assessment of data using computerized overlays and a simple, inexpensive means of constructing and evaluating information in map form and the preparation of final written reports. This system could be useful in many other areas where seismic profiles, precision navigational locations, soundings, diver observations, and core provide a great volume of information that must be compared on regional plots to develop of field maps for geological evaluation and reports.

  11. Fractional crystallization of Si-undersaturated alkaline magmas leading to unmixing of carbonatites on Brava Island (Cape Verde) and a general model of carbonatite genesis in alkaline magma suites

    NASA Astrophysics Data System (ADS)

    Weidendorfer, Daniel; Schmidt, Max W.; Mattsson, Hannes B.

    2016-05-01

    The carbonatites of Brava Island, Cape Verde hot spot, allow to investigate whether they represent small mantle melt fractions or form through extreme fractionation and/or liquid immiscibility from CO2-bearing silicate magmas. The intrusive carbonatites on Brava Island are part of a strongly silica-undersaturated pyroxenite, ijolite, nephelinite, nepheline syenite, combeite-foiditite, carbonatite series. The major and trace element composition of this suite is reproduced by a model fractionating olivine, clinopyroxene, perovskite, biotite, apatite, titanite, sodalite and FeTi oxides, all present as phenocrysts in the rocks corresponding to their fractionation interval. Fractionation of ~90 wt% crystals reproduces the observed geochemical trend from the least evolved ultramafic dikes (bulk X Mg = 0.64) to syenitic compositions. The modelled fractional crystallization leads to alkali enrichment, driving the melt into the carbonatite-silicate miscibility gap. An initial CO2 content of 4000 ppm is sufficient to saturate in CO2 at the point where the rock record suggests continuing unmixing carbonatites from nephelinites to nepheline syenites after 61 wt% fractionation. Such immiscibility is also manifested in carbonatite and silicate domains on a hand-specimen scale. Furthermore, almost identical primary clinopyroxene, biotite and carbonate compositions from carbonatites and nephelinites to nepheline syenites substantiate their conjugate character and our unmixing model. The modelled carbonatite compositions correspond to the natural ones except for their much higher alkali contents. The alkali-poor character of the carbonatites on Brava and elsewhere is likely a consequence of the release of alkali-rich CO2 + H2O fluids during final crystallization, which cause fenitization in adjacent rocks. We propose a general model for carbonatite generation during alkaline magmatism, where the fractionation of heavily Si-undersaturated, alkaline parent melts results in alkali and

  12. Conduit Wall Failure as a Trigger for Transition From Strombolian to Phreatomagmatic Explosive Activity in the Cova de Paúl Crater Eruption on Santo Antão, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Tarff, R. W.; Day, S. J.

    2011-12-01

    Episodes of hazardous phreatomagmatic explosive activity, including Surtseyan activity, occur within otherwise less dangerous effusive to mildly explosive magmatic eruptions at high-elevation vents on many oceanic island volcanoes. The water driving these explosions is sourced from freshwater aquifers within the volcanic edifices. Understanding volcanic and geophysical precursors to, and mechanisms of, the (frequently abrupt) transitions to explosive activity is required as a basis for effective warning and mitigation of the resulting hazards. Here we describe near-vent deposits around the large Cova de Paúl crater on the island of Santo Antão, Cape Verde Islands, which provide some insights into a transition from mild magmatic to violently explosive phreatomagmatic activity in one such eruption. This pre-historic but well-preserved crater formed in a single eruption that produced extensive low-temperature, lithic-rich phreatomagmatic pyroclastic flows and surge deposits; these are interbedded in proximal outcrops with airfall breccia and ash beds containing varying proportions of lithic and juvenile clasts, pointing to a series of climactic explosions within an extended period of milder explosive activity of broadly Surtseyan type. Prior to the transition to phreatomagmatic activity, the eruption had been characterized by mild Strombolian activity that produced scoria and spatter deposits of broadly tephritic composition. The Strombolian deposits contain a distinct population of strongly banded, low-vesicularity angular clasts with strongly prolate vesicles and a notably glassy appearance. These became markedly larger and more abundant just below the transition to the phreatomagmatic deposits. Comparisons of these clasts with the Strombolian scoria suggest that they are fragments of flow-banded chilled margins from the walls of the eruptive conduit. Thermal shattering of these margins to produce the angular glassy clasts may record the onset of groundwater flow

  13. Pueblo of Laguna Utility Authority Renewable Energy Feasibility Study

    SciTech Connect

    Carolyn Stewart, Red Mountain Tribal Energy

    2008-03-31

    The project, “Renewable Energy Feasibility Study” was designed to expand upon previous work done by the Tribe in evaluating utility formation, generation development opportunities, examining options for creating self-sufficiency in energy matters, and integrating energy management with the Tribe’s economic development goals. The evaluation of project locations and economic analysis, led to a focus primarily on solar projects.

  14. U-Pb and K-Ar geochronology in Paleozoic and Mesozoic intrusive rocks of the Coastal Cordillera, Valparaiso, Chile

    USGS Publications Warehouse

    Gana, Paulina; Tosdal, Richard M.

    1996-01-01

    The U-Pb and K-Ar geochronology applied to intrusive rocks from the Coastal Batholith of Central Chile, demonstrates the existence of a basement block of the Mirasol Unit, with a crystallization age of 299??10 Ma, exposed in the northern block of the Melipilla Fault. The age of 214??1 Ma obtained in the 'Dioritas Gne??isicas de Cartagena Unit', indicates that a Late Triassic magmatism took place in this region; it coincides with the end of an extensive crustal melting period, proposed for northern Chile. The ages of the Jurassic plutonic units (Laguna Verde, Sauce, Pen??uelas and Limache) are restricted to the 156-161 Ma interval, showing in certain cases, inherited zircons from an unknown source. The difference between ages obtained using both chronological methods is a few million years, indicating that a short time passed between the crystallization and the cooling of the plutonic bodies, as well as a fast magmatic differentiation process. The Laguna Verde and Sauce Units, experienced a fast uplift, probably as a result of an extensional tectonic process in the magmatic arc, or induced by the magmatic pressure through fracture zones during Middle Jurassic.

  15. Characterization of Two Microbial Isolates from Andean Lakes in Bolivia

    NASA Technical Reports Server (NTRS)

    Demergasso, C.; Blamey, J.; Escudero, L.; Chong, G.; Casamayor, E. O.; Cabrol, N. A.; Grin, E. A.; Hock, A.; Kiss, A.; Borics, G.

    2004-01-01

    We are currently investigating the biological population present in the highest and least explored perennial lakes on earth in the Bolivian and Chilean Andes, including several volcanic crater lakes of more than 6000 m elevation, in combination of microbiological and molecular biological methods. Our samples were collected in saline lakes of the Laguna Blanca Laguna Verde area in the Bolivian Altiplano and in the Licancabur volcano crater (27 deg. 47 min S/67 deg. 47 min. W) in the ongoing project studying high altitude lakes. The main goal of the project is to look for analogies with Martian paleolakes. These Bolivian lakes can be described as Andean lakes following the classification of Chong. We have attempted to isolate pure cultures and phylogenetically characterize prokaryotes that grew under laboratory conditions. Sediment samples taken from the Licancabur crater lake (LC), Laguna Verde (LV), and Laguna Blanca (LB) were analyzed and cultured using enriched liquid media under both aerobic and anaerobic conditions. All cultures were incubated at room temperature (15 to 20 C) and under light exposure. For the reported isolates, 36 hours incubation were necessary for reaching optimal optical densities to consider them viable cultures. Ten serial dilutions starting from 1% inoculum were required to obtain a suitable enriched cell culture to transfer into solid media. Cultures on solid medium were necessary to verify the formation of colonies in order to isolate pure cultures. Different solid media were prepared using several combinations of both trace minerals and carbohydrates sources in order to fit their nutrient requirements. The microorganisms formed individual colonies on solid media enriched with tryptone, yeast extract and sodium chloride. Cells morphology was studied by optical and electronic microscopy. Rodshape morphologies were observed in most cases. Total bacterial genomic DNA was isolated from 50 ml late-exponential phase culture by using the CTAB

  16. 77 FR 51044 - Laguna Cartagena National Wildlife Refuge, PR; Final Comprehensive Conservation Plan and Finding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-23

    ... this process through a Federal Register notice on May 16, 2007 (72 FR 27588). We announce our decision... period via a Federal Register notice on May 2, 2011 (76 FR 24511). Several comments were received... associated plant communities. We will reintroduce native fish to the lagoon and actively support birds...

  17. 76 FR 24512 - Laguna Cartagena National Wildlife Refuge, Lajas, Puerto Rico; Draft Comprehensive Conservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... FR 27588). For more about the refuge, its purposes, and our CCP process, please see that notice... justified to rehabilitate the lagoon for resident and migratory water birds and to provide increased... Lagoon, and grassland habitats. Management programs would continue to be developed and implemented...

  18. Computed discharges at five sites in lower Laguna Madre near Port Isabel, Texas, June 1997

    USGS Publications Warehouse

    East, Jeffrey W.; Solis, R.S.; Ockerman, D.J.

    1998-01-01

    The Texas Water Development Board (TWDB), Texas Parks and Wildlife Department (TPWD), and Texas Natural Resource Conservation Commission (TNRCC) are charged by the Texas Legislature with determining freshwater inflows required to maintain the ecological health of streams, bays, and estuaries in Texas. To determine required inflows, the three agencies collect data and conduct studies on the needs for freshwater inflows to estuaries. The TWDB uses estuarine hydrodynamic and conservativetransport computer models to predict the effects of altering freshwater inflows on estuarine circulation and salinity. To calibrate these models, a variety of water-quality and discharge data are needed.

  19. Community-Based Education in San Juan La Laguna, Solola, Guatemala

    ERIC Educational Resources Information Center

    Abreo, Christina

    2010-01-01

    Indigenous education in Guatemala is currently undergoing a massive overhaul in the depth and breadth of its reach in Maya areas. Although much can be said about the re-evaluation and incorporation of indigenous culture, language and worldview into the schools' curricula, it is still failing to reach the country's adult population. As a result of…

  20. CARBON AND NITROGEN ALLOCATION MODEL FOR THE SEAGRASS THALASSIA TESTUDUNUM IN LOWER LAGUNA MADRE

    EPA Science Inventory

    Inverse modeling methods are a powerful tool for understanding complex physiological relationships between seagrasses and their environment. The power of the method is a result of using ranges of data in a system of constraints to describe the biological system, in this case, t...

  1. Recording of climate and diagenesis through fossil pigments and sedimentary DNA at Laguna Potrok Aike, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, A.; Ariztegui, D.; Leavitt, P. R.; Bunting, L.; Pasado Science Team

    2015-11-01

    Aquatic sediments record past climatic conditions while providing a wide range of ecological niches for microorganisms. Although marine sedimentary microbial assemblages are often defined by their surrounding geochemical conditions, the influence of environmental features upon microbial development and post-depositional survival remains largely unknown in the lacustrine realm. Due to long-term microbial activity, the composition of environmental DNA can be expected to evolve with sediment depth and over time and therefore should reflect both ancient and extant microbial populations, but this hypothesis has rarely been tested using a multiproxy approach. Here geomicrobiological and phylogenetic analyses of a Patagonian maar lake were used to indicate that the different sedimentary microbial assemblages derive from specific lacustrine regimes during defined climatic periods. Two well defined climatic intervals whose sediments harboured active microbial populations and measurable ATP were sampled for a comparative environmental study based on fossil pigments and 16S rRNA gene sequences. Bacterial and archaeal 16S rRNA gene sequences recovered from the Holocene record revealed a microbial community adapted to subsaline conditions actively producing methane during organic matter degradation. These characteristics were associated with sediments resulting from endorheic lake conditions with high evaporative stress and concomitant high algal productivity. Moreover, archaeal clone libraries established throughout the Holocene record indicate an age-related stratification of these populations, consistent with a gradual use of organic substrates after deposition. In contrast, sulphate-reducing bacteria and lithotrophic Archaea were predominant in sediments dated from the Last Glacial Maximum, in which pelagic clays alternated with fine volcanic material characteristic of a lake level highstand and freshwater conditions, but reduced water column productivity. These patterns reveal that microbial assemblages identified from environmental DNA stemmed from a variety of sedimentary niches associated with climate-dependent factors (catchment inflows, water column conditions, productivity), but that initial assemblages underwent structural changes and selective preservation during early diagenesis to result in the final composition entombed in the sediments. We conclude that environmental DNA obtained from lacustrine sediments provides essential genetic information to complement paleoenvironmental indicators and trace climate change and post-depositional diagenetic processes over tens of millennia.

  2. SRTM Perspective of Colored Height and Shaded Relief Laguna Mellquina, Andes Mountains, Argentina

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM)view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters (2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.

    Three visualization methods were combined to produce this image: shading, color coding of topographic height and a perspective view. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations. The perspective is toward the west, 20 degrees off horizontal with 2X vertical exaggeration. The back (west) edge of the data set forms a false skyline within the Andes Range.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of 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 the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

    Size: 55.0 x 37.2 kilometers ( 34.1 x 23.1 miles) Location: 40.4 deg. South lat., 71.3 deg. West lon. Orientation: West toward the top Image Data: Shaded and colored SRTM elevation model Date Acquired: February 2000

  3. SRTM Colored Height and Shaded Relief: Laguna Mellquina, Andes Mountains, Argentina

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM) view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters(2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.

    Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM 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 the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), 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: 55.0 x 37.2 kilometers ( 34.1 x 23.1 miles) Location: 40.4 deg. South lat., 71.3 deg. West lon. Orientation: North toward the top Image Data: Shaded and colored SRTM elevation model Date Acquired: February 2000

  4. Recording of climate and diagenesis through sedimentary DNA and fossil pigments at Laguna Potrok Aike, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, Aurèle; Ariztegui, Daniel; Leavitt, Peter R.; Bunting, Lynda; The Pasado Science Team

    2016-04-01

    Aquatic sediments record past climatic conditions while providing a wide range of ecological niches for microorganisms. In theory, benthic microbial community composition should depend on environmental features and geochemical conditions of surrounding sediments, as well as ontogeny of the subsurface environment as sediment degraded. In principle, DNA in sediments should be composed of ancient and extant microbial elements persisting at different degrees of preservation, although to date few studies have quantified the relative influence of each factor in regulating final composition of total sedimentary DNA assemblage. Here geomicrobiological and phylogenetic analyses of a Patagonian maar lake were used to indicate that the different sedimentary microbial assemblages derive from specific lacustrine regimes during defined climatic periods. Two climatic intervals (Mid-Holocene, 5 ka BP; Last Glacial Maximum, 25 ka BP) whose sediments harbored active microbial populations were sampled for a comparative environmental study based on fossil pigments and 16S rRNA gene sequences. The genetic assemblage recovered from the Holocene record revealed a microbial community displaying metabolic complementarities that allowed prolonged degradation of organic matter to methane. The series of Archaea identified throughout the Holocene record indicated an age-related stratification of these populations brought on by environmental selection during early diagenesis. These characteristics were associated with sediments resulting from endorheic lake conditions and stable pelagic regime, high evaporative stress and concomitant high algal productivity. In contrast, sulphate-reducing bacteria and lithotrophic Archaea were predominant in sediments dated from the Last Glacial Maximum, in which pelagic clays alternated with fine volcanic material characteristic of a lake level highstand and freshwater conditions, but reduced water column productivity. Comparison of sedimentary DNA composition with that of fossil pigments suggested that post-depositional diagenesis resulted in a rapid change in the initial nucleic acid composition and overprint of phototrophic communities by heterotrophic assemblages with preserved pigment compositions. Long DNA sequences (1400-900 bp) appeared to derive from intact bacterial cells, whereas short fragments (290-150 bp) reflected extracellular DNA accumulation in ancient sediments. We conclude that sedimentary DNA obtained from lacustrine deposits provides essential genetic information to complement paleoenvironmental indicators and trace post-depositional diagenetic processes over tens of millennia. However, it remains difficult to estimate the time lag between original deposition of lacustrine sediments and establishment of the final composition of the sedimentary DNA assemblage.

  5. Brus Laguna virus, a Gamboa bunyavirus from Aedeomyia squamipennis collected in Honduras.

    PubMed

    Calisher, C H; Lazuick, J S; Sudia, W D

    1988-10-01

    A virus isolate from Aedeomyia squamipennis collected in Honduras in 1967 was identified as a member of the Gamboa serogroup (family Bunyaviridae, genus Bunyavirus). This is the ninth Gamboa serogroup virus and the eighth shown to be a distinct serotype. PMID:2903690

  6. INCREASE PUBLIC AWARENESS OF THE LOWER LAGUNA MADRE, CBB & GALVESTON BAY ECOSYSTEMS MX964490

    EPA Science Inventory

    Texas Parks and Wildlife currently conducts Coastal Expos that educate individuals. The events primarily target minority and urban populations. The Coastal Expos increase public awareness of Texas coastal ecosystems, why they are important and how individuals can protect them t...

  7. Ecological composition and distribution of the diatoms from the Laguna Superior, Oaxaca, Mexico.

    PubMed

    Moreno-Ruiz, José Luis; Tapia-Garcia, Margarito; Licea, Sergio; Figueroa-Torres, María Guadalupe; Esquivel, Alfonso; Herrera-Galindo, Jorge Eduardo; González-Fernández, José Manuel; González-Macias, Maria Del Carmen

    2011-07-01

    A taxonomic study of diatoms was carried out in a tropical coastal lagoon. Material for this study consists of water samples obtained from February-March 1992 to November-December 2000. Qualitative and quantitative analyses showed the presence of 373 taxa of which the families Bacillariaceae (67 species) and Chaetocerotaceae (37 species) were the most abundant groups. The species Skeletonema costatum, Chaetoceros curvisetus, Coscinodiscus radiatus var. radiatus, Ditylum brightwellii, Thalassiosira eccentrica and Entomoneis alata were found associated with moderate water quality and forming blooms. In addition, a regional comparison between Mexico and South America of the identified species is given. For practical handling, indicative values obtained from their ecological composition are incorporated as well as a code of the floristic list. Achecklist of the species and their occurrence are given. PMID:22315822