INFLUENCE OF SNOWFALL ON BLOOD LEAD LEVELS OF FREE-FLYING BALD EAGLES (HALIAEETUS LEUCOCEPHALUS) IN THE UPPER MISSISSIPPI RIVER VALLEY.

Science.gov (United States)

Lindblom, Ronald A; Reichart, Letitia M; Mandernack, Brett A; Solensky, Matthew; Schoenebeck, Casey W; Redig, Patrick T

2017-10-01

Lead poisoning of scavenging raptors occurs primarily via consumption of game animal carcasses containing lead, which peaks during fall firearm hunting seasons. We hypothesized that snowfall would mitigate exposure by concealing carcasses. We categorized blood lead level (BLL) for a subsample of Bald Eagles (Haliaeetus leucocephalus) from the Upper Mississippi River Valley and described BLL with respect to age, sex, and snowfall. We captured Bald Eagles overwintering in the Upper Mississippi River Valley (n=55) between December 1999 and January 2002. Individual BLL ranged from nondetectable to 335 μg/dL, with 73% of the samples testing positive for acute exposure to lead. Eagle BLL did not significantly differ between age or sex, but levels were higher immediately following the hunting season, and they were lower when the previous month's snowfall was greater than 11 cm. This study suggests a window of time between the white-tailed deer (Odocoileus virginianus) hunting season and the onset of snow when the population experienced peak exposure to lead. Combining these findings with existing research, we offer a narrative of the annual lead exposure cycle of Upper Mississippi River Valley Bald Eagles. These temporal associations are necessary considerations for accurate collection and interpretation of BLL.

Reconstructing late quaternary fluvial process controls in the upper aller valley (north Germany) by means of numerical modeling

NARCIS (Netherlands)

Veldkamp, A.; Berg, van den M.; Dijke, van J.J.; Berg van Saparoea, van den R.M.

2002-01-01

The morpho-genetic evolution of the upper Aller valley (Weser basin, North Germany) was reconstructed using geological and geomorphologic data integrated within a numerical process model framework (FLUVER-2). The current relief was shaped by Pre-Elsterian fluvial processes, Elsterian and Saalian ice

Reconstructing Late Quaternary fluvial process controls in the upper Aller Valley (North Germany) by means of numerical modeling

NARCIS (Netherlands)

Veldkamp, A.; Berg, M.W. van den; Dijke, J.J. van; Berg van den; Saparoea, R.M. van

2002-01-01

The morpho-genetic evolution of the upper Aller valley (Weser basin, North Germany) was reconstructed using geological and geomorphologic data integrated within a numerical process model framework (FLUVER-2). The current relief was shaped by Pre-Elsterian fluvial processes, Elsterian and Saalian ice

Large mammals from the Upper Neopleistocene reference sections in the Tunka rift valley, southwestern Baikal Region

Science.gov (United States)

Shchetnikov, A. A.; Klementiev, A. M.; Filinov, I. A.; Semeney, E. Yu.

2015-03-01

This work presents the data on new finds of fossil macrotheriofauna in the reference sections of the Upper Neopleistocene sediments in the Tunka rift valley (southwestern Baikal Region). The osteological material of a number of Late Neopleistocene mammals including extinct species rare for the Baikal region such as Crocuta spelaea, Panthera spelaea, and Spirocerus kiakhtensis (?) was directly dated with a radiocarbon (AMS) method. The obtained 14C data (18000-35000 years) allow one to rejuvenate significantly the upper limit of the common age interval of habitat of these animals in southern part of Eastern Siberia. Cave hyena and spiral-horned antelope lived in the Tunka rift valley in the Baikal region in Late Kargino time (37-24 ka), and cave lion survived the maximum in the Sartan cryochron in the region (21-20 ka). The study of collected paleontological collections provides a basis for selection of independent Kargino (MIS 3) faunal assemblages to use them for regional biostratigraphic analysis of Pleistocene deposits. Radiocarbon age dating of samples allows one to attribute confidently all paleofaunal remains available to the second half of the Late Pleistocene.

Tuning Valley Polarization in a WSe_{2} Monolayer with a Tiny Magnetic Field

Directory of Open Access Journals (Sweden)

T. Smoleński

2016-05-01

Full Text Available In monolayers of semiconducting transition metal dichalcogenides, the light helicity (σ^{+} or σ^{-} is locked to the valley degree of freedom, leading to the possibility of optical initialization of distinct valley populations. However, an extremely rapid valley pseudospin relaxation (at the time scale of picoseconds occurring for optically bright (electric-dipole active excitons imposes some limitations on the development of opto-valleytronics. Here, we show that valley pseudospin relaxation of excitons can be significantly suppressed in a WSe_{2} monolayer, a direct-gap two-dimensional semiconductor with the exciton ground state being optically dark. We demonstrate that the already inefficient relaxation of the exciton pseudospin in such a system can be suppressed even further by the application of a tiny magnetic field of about 100 mT. Time-resolved spectroscopy reveals the pseudospin dynamics to be a two-step relaxation process. An initial decay of the pseudospin occurs at the level of dark excitons on a time scale of 100 ps, which is tunable with a magnetic field. This decay is followed by even longer decay (>1  ns, once the dark excitons form more complex pseudo-particles allowing for their radiative recombination. Our findings of slow valley pseudospin relaxation easily manipulated by the magnetic field open new prospects for engineering the dynamics of the valley pseudospin in transition metal dichalcogenides.

Combinatorial vector fields and the valley structure of fitness landscapes.

Science.gov (United States)

Stadler, Bärbel M R; Stadler, Peter F

2010-12-01

Adaptive (downhill) walks are a computationally convenient way of analyzing the geometric structure of fitness landscapes. Their inherently stochastic nature has limited their mathematical analysis, however. Here we develop a framework that interprets adaptive walks as deterministic trajectories in combinatorial vector fields and in return associate these combinatorial vector fields with weights that measure their steepness across the landscape. We show that the combinatorial vector fields and their weights have a product structure that is governed by the neutrality of the landscape. This product structure makes practical computations feasible. The framework presented here also provides an alternative, and mathematically more convenient, way of defining notions of valleys, saddle points, and barriers in landscape. As an application, we propose a refined approximation for transition rates between macrostates that are associated with the valleys of the landscape.

Landform Evolution of the Zanskar Valley, Ladakh Himalaya.

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2006-01-01

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

Factors favorable to frequent extreme precipitation in the upper Yangtze River Valley

Science.gov (United States)

Tian, Baoqiang; Fan, Ke

2013-08-01

Extreme precipitation events in the upper Yangtze River Valley (YRV) have recently become an increasingly important focus in China because they often cause droughts and floods. Unfortunately, little is known about the climate processes responsible for these events. This paper investigates factors favorable to frequent extreme precipitation events in the upper YRV. Our results reveal that a weakened South China Sea summer monsoon trough, intensified Eurasian-Pacific blocking highs, an intensified South Asian High, a southward subtropical westerly jet and an intensified Western North Pacific Subtropical High (WNPSH) increase atmospheric instability and enhance the convergence of moisture over the upper YRV, which result in more extreme precipitation events. The snow depth over the eastern Tibetan Plateau (TP) in winter and sea surface temperature anomalies (SSTAs) over three key regions in summer are important external forcing factors in the atmospheric circulation anomalies. Deep snow on the Tibetan Plateau in winter can weaken the subsequent East Asian summer monsoon circulation above by increasing the soil moisture content in summer and weakening the land-sea thermal contrast over East Asia. The positive SSTA in the western North Pacific may affect southwestward extension of the WNPSH and the blocking high over northeastern Asia by arousing the East Asian-Pacific pattern. The positive SSTA in the North Atlantic can affect extreme precipitation event frequency in the upper YRV via a wave train pattern along the westerly jet between the North Atlantic and East Asia. A tripolar pattern from west to east over the Indian Ocean can strengthen moisture transport by enhancing Somali cross-equatorial flow.

The use of antigen ELISA to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley, Western Ethiopia

International Nuclear Information System (INIS)

Tewelde, N.; Kebede, A.; Tsegaye, A.

1997-01-01

Blood and serum samples were collected from a tsetse free zone in the central highlands of Ethiopia. The samples were collected to determine the specificity and establish percentage positivity cut-off points of the antigen ELISA. Blood samples collected from these areas were negative for trypanosomosis using Standard Trypanosome Detection Methods (STDM). Ag-ELISA, in contrast, detected circulating trypanosomal antigens in 7.6% of the serum samples collected. Similarly, samples were collected from a tsetse infested zone in the upper Didessa valley, western Ethiopia, to assess the sensitivity of the Ag-ELISA. STDM detected trypanosomal infections in the range of 15.8 and 16.7% of blood samples from this zone. On the other hand, Ag-ELISA, indicated the presence of circulating trypanosomal antigens in 38.6% of serum samples tested. Moreover, Ag-ELISA was used to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley. There were great differences in the prevalence rates of trypanosomosis, as revealed by the STDM and Ag-ELISA, between the tsetse controlled and tsetse infested zones of the upper Didessa valley. Generally, the Ag-ELISA revealed the presence of circulating trypanosomal antigens in only 43.7% of patent infections. Nevertheless, the test detected 318 more cases which were not diagnosed by any one of the STDM used. More interestingly, Ag-ELISA indicated the widespread presence of T. brucei in the cattle sampled in all zones. (author). 11 refs, 4 tabs

The use of antigen ELISA to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley, Western Ethiopia

Energy Technology Data Exchange (ETDEWEB)

Tewelde, N; Kebede, A; Tsegaye, A [National Tsetse and Trypanosomiasis Investigation and Control Centre (NTTICC), Bedelle (Ethiopia)

1997-02-01

Blood and serum samples were collected from a tsetse free zone in the central highlands of Ethiopia. The samples were collected to determine the specificity and establish percentage positivity cut-off points of the antigen ELISA. Blood samples collected from these areas were negative for trypanosomosis using Standard Trypanosome Detection Methods (STDM). Ag-ELISA, in contrast, detected circulating trypanosomal antigens in 7.6% of the serum samples collected. Similarly, samples were collected from a tsetse infested zone in the upper Didessa valley, western Ethiopia, to assess the sensitivity of the Ag-ELISA. STDM detected trypanosomal infections in the range of 15.8 and 16.7% of blood samples from this zone. On the other hand, Ag-ELISA, indicated the presence of circulating trypanosomal antigens in 38.6% of serum samples tested. Moreover, Ag-ELISA was used to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley. There were great differences in the prevalence rates of trypanosomosis, as revealed by the STDM and Ag-ELISA, between the tsetse controlled and tsetse infested zones of the upper Didessa valley. Generally, the Ag-ELISA revealed the presence of circulating trypanosomal antigens in only 43.7% of patent infections. Nevertheless, the test detected 318 more cases which were not diagnosed by any one of the STDM used. More interestingly, Ag-ELISA indicated the widespread presence of T. brucei in the cattle sampled in all zones. (author). 11 refs, 4 tabs.

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

KAUST Repository

Kim, J.

2014-12-04

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

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

KAUST Repository

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

2014-01-01

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

Irrigation channels of the Upper Rhone valley (Switzerland). Geomorphological analysis of a cultural heritage

Science.gov (United States)

Reynard, Emmanuel

2016-04-01

The Upper Rhone valley (Canton of Valais, Switzerland) is characterised by dry climatic conditions that explain the presence of an important network (about 800 km) of irrigation channels - called Bisses in the French-speaking part of the canton or Suonen in the German-speaking area - dating back to the Middle Ages. This network constitutes a cultural heritage and during the last 30 years these agricultural infrastructures have sparked a renewed interest for tourist and cultural reasons. Indeed, the paths along the channels are used as tourist trails and several abandoned channels have been renovated for tourist use. Based on an inventory of the Bisses/Suonen of Valais, the proposed communication has three aims: (1) to analyse the geomorphological context (morphometric analysis, structural geomorphology, main processes) of various types of channels and to show the impact of the geomorphological context on the building techniques; (2) to identify particularly active processes along the channels; (3) to classify the Bisses/Suonen according to their geomorphological value and to their geomorphological sensitivity, and to propose managing measures. Structural and climatic conditions influence the geomorphological context of the channels. In a structural point of view, irrigation channels are developed in three main contexts: (1) in the Aar Massif crystalline basement; (2) in the limestone and marl cover nappes of the Helvetic Alps; (3) in the metamorphic cover nappes of the Penninic domain. The Rhone River valley is boarded by two high mountain ranges: the Penninic Alps in the South and the Bernese Alps in the North. Because of rain shadow effects, the climate is relatively dry and, between Brig and Martigny, annual rainfall is not more than 600 mm at 500 m ASL and 800 mm at 1600 m ASL. Nevertheless, due to important vertical precipitation gradients annual rainfall totals are high at high altitudes. On the southern facing tributary valleys, the dry climatic conditions

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

Science.gov (United States)

Gaines, E. P.

2013-12-01

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

Preliminary Study of the Effect of the Proposed Long Lake Valley Project Operation on the Transport of Larval Suckers in Upper Klamath Lake, Oregon

Science.gov (United States)

Wood, Tamara M.

2009-01-01

A hydrodynamic model of Upper Klamath and Agency Lakes, Oregon, was used to explore the effects of the operation of proposed offstream storage at Long Lake Valley on transport of larval suckers through the Upper Klamath and Agency Lakes system during May and June, when larval fish leave spawning sites in the Williamson River and springs along the eastern shoreline and become entrained in lake currents. A range in hydrologic conditions was considered, including historically high and low outflows and inflows, lake elevations, and the operation of pumps between Upper Klamath Lake and storage in Long Lake Valley. Two wind-forcing scenarios were considered: one dominated by moderate prevailing winds and another dominated by a strong reversal of winds from the prevailing direction. On the basis of 24 model simulations that used all combinations of hydrology and wind forcing, as well as With Project and No Action scenarios, it was determined that the biggest effect of project operations on larval transport was the result of alterations in project management of the elevation in Upper Klamath Lake and the outflow at the Link River and A Canal, rather than the result of pumping operations. This was because, during the spring time period of interest, the amount of water pumped between Upper Klamath Lake and Long Lake Valley was generally small. The dominant effect was that an increase in lake elevation would result in more larvae in the Williamson River delta and in Agency Lake, an effect that was enhanced under conditions of wind reversal. A decrease in lake elevation accompanied by an increase in the outflow at the Link River had the opposite effect on larval concentration and residence time.

Status and management of watersheds in the Upper Pokhara Valley, Nepal

Science.gov (United States)

Thapa, Gopal B.; Weber, Karl E.

1995-07-01

Contributing to the debate on the causes of Himalayan environmental degradation, the status and management of four watersheds in the Upper Pokhara Valley were studied using information available from land use analysis, household surveys conducted in 1989 and 1992, deliberations held with villagers, and field observations. Accordingly, areas under forests and grazing lands were found being depleted at relatively high rates between 1957 and 1978 due mainly to the government policy of increasing national revenue by expansion of agricultural lands, nationalization of forests, steadily growing population, and dwindling household economy. Despite the steady growth of population, this process had remarkably slackened since 1978, owing primarily to remaining forests being located in very, steep slopes and implementation of the community forestry program. Forests with relatively sparase tree density, however, and grazing lands in the vicinity of settlements have been undergoing degradation due to fuelwood and fodder collection and livestock grazing. In many instances, this is aggravated by weak resource management institutions. Being particularly aware of the economic implication of land degradation, farmers have adopted assorted land management practices. Still a substantial proportion of bari lands in the hill slopes is vulnerable to accelerating degradation, as the arable cropping system is being practiced there as well. The perpetuation of the local subsistence economy is certain to lead, to a further deterioration of the socioeconomic and environmental conditions of watersheds. To facilitate environmental conservation and ecorestructuring for sustainable development, a broad watershed management strategy is outlined with focus on alleviating pressure on natural resources.

Analog model study of the ground-water basin of the Upper Coachella Valley, California

Science.gov (United States)

Tyley, Stephen J.

1974-01-01

An analog model of the ground-water basin of the upper Coachella Valley was constructed to determine the effects of imported water on ground-water levels. The model was considered verified when the ground-water levels generated by the model approximated the historical change in water levels of the ground-water basin caused by man's activities for the period 1986-67. The ground-water basin was almost unaffected by man's activities until about 1945 when ground-water development caused the water levels to begin to decline. The Palm Springs area has had the largest water-level decline, 75 feet since 1986, because of large pumpage, reduced natural inflow from the San Gorgonio Pass area, and diversions of natural inflows at Snow and Falls Creeks and Chino Canyon starting in 1945. The San Gorgonio Pass inflow had been reduced from about 18,000 acre-feet in 1986 to about 9,000 acre-feet by 1967 because of increased ground-water pumpage in the San Gorgonio Pass area, dewatering of the San Gorgonio Pass area that took place when the tunnel for the Metropolitan Water District of Southern California was drilled, and diversions of surface inflow at Snow and Falls Creeks. In addition, 1944-64 was a period of below-normal precipitation which, in part, contributed to the declines in water levels in the Coachella Valley. The Desert Hot Springs, Garnet Hill, and Mission Creek subbasins have had relatively little development; consequently, the water-level declines have been small, ranging from 5 to 15 feet since 1986. In the Point Happy area a decline of about 2 feet per year continued until 1949 when delivery of Colorado River water to the lower valley through the Coachella Canal was initiated. Since 1949 the water levels in the Point Happy area have been rising and by 1967 were above their 1986 levels. The Whitewater River subbasin includes the largest aquifer in the basin, having sustained ground-water pumpage of about 740,000 acre-feet from 1986 to 1967, and will probably

Petroleum systems of the Upper Magdalena Valley, Colombia

Energy Technology Data Exchange (ETDEWEB)

Sarmiento, L.F.; Rangel, A. [Instituto Colombiano del Petroleo, Bucaramanga (Colombia). ECOPETROL

2004-03-01

In the Upper Magdalena Valley, Colombia, four petroleum systems were identified. Two petroleum systems are located in the Girardot sub-basin and the other two in the Neiva sub- basin. Limestones laterally changing to shales of the lower part of the Villeta Gp, deposited during Albian and Turonian marine flooding events, constitutes the main source rocks of the oil families. These rocks contain 1-4% TOC and type II kerogen. The littoral quartz arenites of the Caballos (Albian) and Monserrate (Maastrichtian) Fms. are the main reservoir rocks. Seal rocks are Cretaceous and Paleocene shales. Overburden includes the Cretaceous rocks and the Tertiary molasse deposited simultaneously with development of two opposite verging thrust systems during Cenozoic time. These deformation events were responsible for trap creation. Except for the Villarrica area, where the source rock reached maturity during the Paleocene, generation occurred during Miocene. Two oil families are identified, each in both sub-basins: One derived from a clay-rich source and the second from a carbonate-rich source rock lithofacies of the lower part of Villeta Gp. Geochemical source-rock to oil correlations are demonstrated for the three of the petroleum systems. Up-dip lateral migration distances are relatively short and faults served as vertical migration pathways. A huge amount of oil was probably degraded at surface, as a result of Miocene deformation and erosion. (author)

A proposal of conceptual model for Pertuso Spring discharge evaluation in the Upper Valley of Aniene River

Directory of Open Access Journals (Sweden)

Giuseppe Sappa

2016-10-01

Full Text Available The Upper Aniene River basin is part of a large karst aquifer, which interacts with the river, and represents the most important water resource in the southeast part of Latium Region, Central Italy, used for drinking, agriculture and hydroelectric supplies. This work provides hydrogeochemical data and their interpretations for 1 spring and 2 cross section of Aniene River, monitored from July 2014 to December 2015, in the Upper Valley of Aniene River, to identify flow paths and hydrogeochemical processes governing groundwater-surface water interactions in this region. These activities deal with the Environmental Monitoring Plan made for the catchment work project of the Pertuso Spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important drinking water network in the South part of Rome district. Discharge measurements and hydrogeochemical data were analyzed to develop a conceptual model of aquifer-river interaction, with the aim of achieving proper management and protection of this important hydrogeological system. All groundwater samples are characterized as Ca-HCO3 type. Geochemical modeling and saturation index computation of the water samples show that groundwater and surface water chemistry in the study area was evolved through the interaction with carbonate minerals. All groundwater samples were undersaturated with respect to calcite and dolomite, however some of the Aniene River samples were saturated with respect to dolomite. The analysis of Mg2+/Ca2+ ratios indicates that the dissolution of carbonate minerals is important for groundwater and surface water chemistry, depending on the hydrological processes, which control the groundwater residence time and chemical equilibria in the aquifer.

The upper Sava valley at the three border area of Austria, Italy ans Yugoslavia - a geographic perspective

Directory of Open Access Journals (Sweden)

Vladimir Klemenčič

1990-12-01

Full Text Available An analysis on the alpine spatial factors was carried out in the area of Kranjska gora and the Upper Sava valley, in the NW corner of Slovenia (Yugoslavia. As a part of a similar study Austrians and Italians, at their side of the border, ther research focused on future regional development. The so called "Three Border Area", in the above-mentioned countries, candidates for the winter olympics in 1998 and in general seek cross-border cooperation. The mountainous region of the Julian Alps here is separated from another mountainous and border strech of the Karawanks by the deep glacial river valley of the river Sava. The central place within the valley is Kranjska Gora — a famous winter šport center. World cup alpine skiing races and ski-jumping competitions (Planica take place here every year. The past post-war period were not very much in favour of developing tourism in general. That is why many inhabitants of the Upper Sava Valley decided to abandon agriculture and look for jobs in the governmentaly supported steel mills of the communal center of Jesenice. Daily migration accures today in both directions: man from the area migrate to the industry, woman from the above-mentioned town travel daily the same distance to work in hotels. Lately a couple of hundred inhabitants found jobs also in the nearby employment centers of Carinthia and Friuli-Venezia Giulia. Future complex regional development in the area of the bordering countries of Italy, Austria and Yugoslavia can be supported in the part of Slovenia with the tradition of mountaineering and ski jumping as well as vvith an international tradition in hosting guests from distantplaces and vvith the tradition of organizing sporting events. The relatively "underdeveloped alpine landscape" here. mostly within the borders of the Triglav National Park could attract visitors too. Among other developments Mountaineering — and Ski-jumping Schools and Courses of

Valley Zeeman splitting of monolayer MoS2 probed by low-field magnetic circular dichroism spectroscopy at room temperature

Science.gov (United States)

Wu, Y. J.; Shen, C.; Tan, Q. H.; Shi, J.; Liu, X. F.; Wu, Z. H.; Zhang, J.; Tan, P. H.; Zheng, H. Z.

2018-04-01

The valley Zeeman splitting of monolayer two-dimensional (2D) materials in the magnetic field plays an important role in the valley and spin manipulations. In general, a high magnetic field (6-65 T) and low temperature (2-30 K) were two key measurement conditions to observe the resolvable valley Zeeman splitting of monolayer 2D materials in current reported experiments. In this study, we experimentally demonstrate an effective measurement scheme by employing magnetic circular dichroism (MCD) spectroscopy, which enables us to distinguish the valley Zeeman splitting under a relatively low magnetic field of 1 T at room temperature. MCD peaks related to both A and B excitonic transitions in monolayer MoS2 can be clearly observed. Based on the MCD spectra under different magnetic fields (-3 to 3 T), we obtained the valley Zeeman splitting energy and the g-factors of A and B excitons, respectively. Our results show that MCD spectroscopy is a high-sensitive magneto-optical technique to explore the valley and spin manipulation in 2D materials.

Petrotectonic characteristics, geochemistry, and U-Pb geochronology of Jurassic plutons in the Upper Magdalena Valley-Colombia: Implications on the evolution of magmatic arcs in the NW Andes

Science.gov (United States)

Rodríguez, G.; Arango, M. I.; Zapata, G.; Bermúdez, J. G.

2018-01-01

Field, petrographic, and geochemical characterization along with U-Pb zircon geochronology of the Jurassic plutons exposed in the Upper Magdalena Valley (Colombia) allowed recognizing distinct western and eastern suites formed in at least three magmatic pulses. The western plutons crop out between the eastern flank of the Central Cordillera and the Las Minas range, being limited by the Avirama and the Betania-El Agrado faults. The western suite comprises a quartz monzonite - quartz monzodiorite - quartz diorite series and subordinate monzogranites. Chemically, the rocks are high-K calc-alkaline I-type granitoids (some reaching the shoshonitic series) with metaluminous of magnesium affinity. Trace-element tectonic discrimination is consistent with magmatism in a continental arc environment. Most rocks of this suite crystallized between 195 and 186 Ma (Early Jurassic, Pliensbachian), but locally some plutons yielded younger ages between 182 and 179 Ma (Early Jurassic, Toarcian). The eastern suite crops out in the eastern margin of the Upper Magdalena Valley, east of the Betania - El Agrado fault. Plutons of this unit belong to the monzogranite series with rock types ranging between syenogranites and granodiorites. They are high-K calc-alkaline continental granitoids, some metaluminous and some peraluminous, related to I-type granites generated in a volcanic arc. Crystallization of the suite was between 173 and 169 Ma (Middle Jurassic, Aalenian-Bajocian), but locally these rocks contain zircon with earlier inherited ages related to the magmatic pulse of the western suite between 182 and 179 Ma (Early Jurassic, Toarcian). The evolution of the Jurassic plutons in the Upper Magdalena Valley is best explained by onset or increase in subduction erosion of the accretionary prism. This explains the eastward migration of the arc away from the trench. Subduction of prism sediments increased the water flux from the subducting slab, decreasing solidus temperatures, therefore

Superconductivity in Strong Magnetic Field (Greater Than Upper Critical Field)

International Nuclear Information System (INIS)

Tessema, G.X.; Gamble, B.K.; Skove, M.J.; Lacerda, A.H.; Mielke, C.H.

1998-01-01

The National High Magnetic Field Laboratory, funded by the National Science Foundation and other US federal Agencies, has in recent years built a wide range of magnetic fields, DC 25 to 35 Tesla, short pulse 50 - 60 Tesla, and quasi-continuous 60 Tesla. Future plans are to push the frontiers to 45 Tesla DC and 70 to 100 Tesla pulse. This user facility, is open for national and international users, and creates an excellent tool for materials research (metals, semiconductors, superconductors, biological systems ..., etc). Here we present results of a systematic study of the upper critical field of a novel superconducting material which is considered a promising candidate for the search for superconductivity beyond H c2 as proposed by several new theories. These theories predict that superconductors with low carrier density can reenter the superconducting phase beyond the conventional upper critical field H c2 . This negates the conventional thinking that superconductivity and magnetic fields are antagonistic

Magnetic field induced strong valley polarization in the three-dimensional topological semimetal LaBi

Science.gov (United States)

Kumar, Nitesh; Shekhar, Chandra; Klotz, J.; Wosnitza, J.; Felser, Claudia

2017-10-01

LaBi is a three-dimensional rocksalt-type material with a surprisingly quasi-two-dimensional electronic structure. It exhibits excellent electronic properties such as the existence of nontrivial Dirac cones, extremely large magnetoresistance, and high charge-carrier mobility. The cigar-shaped electron valleys make the charge transport highly anisotropic when the magnetic field is varied from one crystallographic axis to another. We show that the electrons can be polarized effectively in these electron valleys under a rotating magnetic field. We achieved a polarization of 60% at 2 K despite the coexistence of three-dimensional hole pockets. The valley polarization in LaBi is compared to the sister compound LaSb where it is found to be smaller. The performance of LaBi is comparable to the highly efficient bismuth.

Valley polarization in bismuth

Science.gov (United States)

Fauque, Benoit

2013-03-01

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

Title V Operating Permit: QEP Field Services Company - Wonsits Valley Compressor Station

Science.gov (United States)

Response to public comments and the Title V Operating Permit for the QEP Field Services Company, Wonsits Valley Compressor Station, located on the Uintah and Ouray Indian Reservation in Uintah County, Utah.

Valley-locked thermospin effect in silicene and germanene with asymmetric magnetic field induced by ferromagnetic proximity effect

Science.gov (United States)

Zhai, Xuechao; Wang, Yun-Tong; Wen, Rui; Wang, Shu-Xuan; Tian, Yue; Zhou, Xingfei; Chen, Wei; Yang, Zhihong

2018-02-01

Silicene and germanene, as graphenelike materials with observable spin-orbit couplings and two distinctive valleys, have potential applications in future low-dissipation spintronics and valleytronics. We here propose a magnetic system of silicene or germanene intercalated between two ferromagetic (FM) dielectric layers, and find that the system with a proximity-induced asymmetric magnetic field supports an attractive phenomenon named the valley-locked spin-dependent Seebeck effect (VL-SSE) driven by a thermal gradient. The VL-SSE indicates that the carries from only one valley could be thermally excited, with opposite spin polarization counterpropagating along the thermal gradient direction, while nearly no carrier from the other insulating valley is excited due to the relatively wide band gap. It is also illustrated that the VL-SSE here does not survive in the usual FM or anti-FM systems, and can be destroyed by the overlarge temperature broadening. Moreover, we prove that the signal for VL-SSE can be weakened gradually with the enhancement of the local interlayer electric field, and be strengthened lineally by increasing the source-drain temperature difference in a caloritronic field effect transistor. Further calculations indicate that the VL-SSE is robust against many perturbations, including the global and local Fermi levels as well as the magnetic strength. These findings about the valley-locked thermospin effect provide a nontrivial and convenient dimension to control the quantum numbers of spin and valley and are expected to be applied in future spin-valley logic circuits and energy-saving devices.

New discoveries in Upper and Middle Magdalena

International Nuclear Information System (INIS)

Carta Petrolera

1998-01-01

In six association contracts and one risk participation contract may give Colombia the possibility of finding new oil reserves. These prospects, located in the Upper and Middle Magdalena Valleys and the Eastern Plains. the completion process, evaluation, confirmation and commercialization should be in the next two years, these new discoveries also reveal interesting geological aspects; some in fractured limestone, similar to the found at Maracaibo lake in Venezuela, where vast oil fields were discovered

An integrated approach to the Environmental Monitoring Plan of the Pertuso spring (Upper Valley of Aniene River

Directory of Open Access Journals (Sweden)

Giuseppe Sappa

2014-06-01

Full Text Available Quantitative assessment of groundwater and surface water is an important tool for sustainable management and protection of these important resources. This paper deals with the design of a multi-disciplinary monitoring plan related to the catchment project of the Pertuso spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important water network in the South part of Roma district. According to the Legislative Decree 152/2006, as modified by DM 260/2010, any infrastructure design should take in consideration an Environmental Monitoring Plan for the hydrogeological settings of the study area. Thus, the hydrogeological characterization combined with an Environmental Monitoring Plan provides to evaluate the potential adverse environmental impacts due catchment works. For water resources assessment and management, the quantification of groundwater recharge is a preliminary step. As a matter of fact, it has been included the quantitative characterization of the Pertuso spring, in the aim of to protect catchment area, which is directly affect by the natural hydrogeological balance of this aquifer. Thus, a multi-disciplinary monitoring plan has been set up, including quantitative and hydrogeochemical measurements, both for groundwater and surface water of the Upper Valley of Aniene River. The target of this Environmental Monitoring Plan is to set up the background framework on the hydromorphological, physico-chemical and biological properties of water resources in the water basin influenced aim by any potential environmental impact due to the construction activities. The Environmental Monitoring Plan and main features of the monitoring network will be presented in this study.

Impacts of using reformulated and oxygenated fuel blends on the regional air quality of the upper Rhine valley

Directory of Open Access Journals (Sweden)

J.-F. Vinuesa

2006-01-01

Full Text Available The effects of using three alternative gasoline fuel blends on regional air quality of the upper Rhine valley have been investigated. The first of the tested fuels is oxygenated by addition of ethyl-tertio-butyl ether (ETBE, the second is based on a reformulation of its composition and the third on is both oxygenated and reformulated. The upper Rhine valley is a very sensitive region for pollution episodes and several meteorological and air quality studies have already been performed. High temporal and spatial emission inventories are available allowing relevant and realistic modifications of the emission inventories. The calculation period, i.e., 11 May 1998, corresponds to a regional photochemical ozone pollution episode during which ozone concentrations exceeded several times the information threshold of the ozone directive of the European Union (180 μg m-3 as 1 hourly average. New emission inventories are set up using specific emission factors related to the alternative fuels by varying the fraction of gasoline passenger cars (from 50% to 100% using the three fuel blends. Then air quality modeling simulations are performed using these emission inventories over the upper Rhine valley. The impact of alternative fuels on regional air quality is evaluated by comparing these simulations with the one using a reference emission inventory, e.g., where no modifications of the fuel composition are included. The results are analyzed by focusing on peak levels and daily averaged concentrations. The use of the alternative fuels leads to general reductions of ozone and volatile organic compounds (VOC and increases of NOx levels. We found different behaviors related to the type of the area of concern i.e. rural or urban. The impacts on ozone are enhanced in urban areas where 15% reduction of the ozone peak and daily averaged concentrations can be reached. This behavior is similar for the NOx for which, in addition, an increase of the levels can be noted

Assessing the cost of groundwater pollution: the case of diffuse agricultural pollution in the Upper Rhine valley aquifer.

Science.gov (United States)

Rinaudo, J-D; Arnal, C; Blanchin, R; Elsass, P; Meilhac, A; Loubier, S

2005-01-01

This paper presents an assessment of the costs of diffuse groundwater pollution by nitrates and pesticides for the industrial and the drinking water sectors in the Upper Rhine valley, France. Pollution costs which occurred between 1988 and 2002 are described and assessed using the avoidance cost method. Geo-statistical methods (kriging) are then used to construct three scenarios of nitrate concentration evolution. The economic consequences of each scenario are then assessed. The estimates obtained are compared with the results of a contingent valuation study carried out in the same study area ten years earlier.

Reevaluation of the Piermont-Frontenac allochthon in the Upper Connecticut Valley: Restoration of a coherent Boundary Mountains–Bronson Hill stratigraphic sequence

Science.gov (United States)

Rankin, Douglas W.; Tucker, Robert D.; Amelin, Yuri

2013-01-01

The regional extent and mode and time of emplacement of the Piermont-Frontenac allochthon in the Boundary Mountains–Bronson Hill anticlinorium of the Upper Connecticut Valley, New Hampshire–Vermont, are controversial. Moench and coworkers beginning in the 1980s proposed that much of the autochthonous pre–Middle Ordovician section of the anticlinorium was a large allochthon of Silurian to Early Devonian rocks correlated to those near Rangeley, Maine. This ∼200-km-long allochthon was postulated to have been transported westward in the latest Silurian to Early Devonian as a soft-sediment gravity slide on a hypothesized Foster Hill fault. New mapping and U-Pb geochronology do not support this interpretation. The undisputed Rangeley sequence in the Bean Brook slice is different from the disputed sequence in the proposed larger Piermont-Frontenac allochthon, and field evidence for the Foster Hill fault is lacking. At the type locality on Foster Hill, the postulated “fault” is a stratigraphic contact within the Ordovician Ammonoosuc Volcanics. The proposed Foster Hill fault would place the Piermont-Frontenac allochthon over the inverted limb of the Cornish(?) nappe, which includes the Emsian Littleton Formation, thus limiting the alleged submarine slide to post-Emsian time. Mafic dikes of the 419 Ma Comerford Intrusive Complex intrude previously folded strata attributed to the larger Piermont-Frontenac allochthon as well as the autochthonous Albee Formation and Ammonoosuc Volcanics. The Lost Nation pluton intruded and produced hornfels in previously deformed Albee strata. Zircons from an apophysis of the pluton in the hornfels have a thermal ionization mass spectrometry 207Pb/206Pb age of 444.1 ± 2.1 Ma. Tonalite near Bath, New Hampshire, has a zircon sensitive high-resolution ion microprobe 206Pb/238U age of 492.5 ± 7.8 Ma. The tonalite intrudes the Albee Formation, formerly interpreted as the Silurian Perry Mountain Formation of the proposed allochthon

Geologic map of the upper Arkansas River valley region, north-central Colorado

Science.gov (United States)

Kellogg, Karl S.; Shroba, Ralph R.; Ruleman, Chester A.; Bohannon, Robert G.; McIntosh, William C.; Premo, Wayne R.; Cosca, Michael A.; Moscati, Richard J.; Brandt, Theodore R.

2017-11-17

This 1:50,000-scale U.S. Geological Survey geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This report also incorporates new detailed geologic mapping of previously poorly understood areas within the map area and reinterprets previously studied areas. The mapped region extends into the Proterozoic metamorphic and intrusive rocks in the Sawatch Range west of the valley and the Mosquito Range to the east. Paleozoic rocks are preserved along the crest of the Mosquito Range, but most of them have been eroded from the Sawatch Range. Numerous new isotopic ages better constrain the timing of both Proterozoic intrusive events, Late Cretaceous to early Tertiary intrusive events, and Eocene and Miocene volcanic episodes, including widespread ignimbrite eruptions. The uranium-lead ages document extensive about 1,440-million years (Ma) granitic plutonism mostly north of Buena Vista that produced batholiths that intruded an older suite of about 1,760-Ma metamorphic rocks and about 1,700-Ma plutonic rocks. As a result of extension during the Neogene and possibly latest Paleogene, the graben underlying the valley is filled with thick basin-fill deposits (Dry Union Formation and older sediments), which occupy two sub-basins separated by a bedrock high near the town of Granite. The Dry Union Formation has undergone deep erosion since the late Miocene or early Pliocene. During the Pleistocene, ongoing steam incision by the Arkansas River and its major tributaries has been interrupted by periodic aggradation. From Leadville south to Salida as many as seven mapped alluvial depositional units, which range in age from early to late Pleistocene, record periodic aggradational events along these streams that are

Sedimentology of the Essaouira Basin (Meskala Field) in context of regional sediment distribution patterns during upper Triassic pluvial events

Science.gov (United States)

Mader, Nadine K.; Redfern, Jonathan; El Ouataoui, Majid

2017-06-01

Upper Triassic continental clastics (TAGI: Trias Argilo-Greseux Inferieur) in the Essaouira Basin are largely restricted to the subsurface, which has limited analysis of the depositional environments and led to speculation on potential provenance of the fluvial systems. Facies analysis of core from the Meskala Field onshore Essaouira Basin is compared with tentatively time-equivalent deposits exposed in extensive outcrops in the Argana Valley, to propose a process orientated model for local versus regional sediment distribution patterns in the continuously evolving Moroccan Atlantic rift during Carnian to Norian times. The study aims to unravel the climatic overprint and improve the understanding of paleo-climatic variations along the Moroccan Atlantic margin to previously recognised Upper Triassic pluvial events. In the Essaouira Basin, four facies associations representing a progressive evolution from proximal to distal facies belts in a continental rift were established. Early ephemeral braided river systems are succeeded by a wet aeolian sandflat environment with a strong arid climatic overprint (FA1). This is followed by the onset of perennial fluvial deposits with extensive floodplain fines (FA2), accompanied by a distinct shift in fluvial style, suggesting increase in discharge and related humidity, either locally or in the catchment area. The fluvial facies transitions to a shallow lacustrine or playa lake delta environment (FA3), which exhibits cyclical abandonment. The delta is progressively overlain by a terminal playa with extensive, mottled mudstones (FA4), interpreted to present a return from cyclical humid-arid conditions to prevailing aridity in the basin. In terms of regional distribution and sediment source provenance, paleocurrent data from Carnian to Norian deposits (T5 to T8 member) in the Argana Valley suggest paleoflow focused towards the S and SW, not directed towards the Meskala area in the NW as previously suggested. A major depo

A Transformative Undergraduate Field Trip to the Grand Canyon and Death Valley

Science.gov (United States)

Smith, J. A.

2014-12-01

Seeing the iconic Grand Canyon and Death Valley in person is a transformative experience for most geologists, including nine undergraduate geology students from upstate New York. The students were enrolled in a one-credit course designed around a nine-day spring-break field trip to Grand Canyon National Park (GCNP) and Death Valley National Park (DVNP). We met once a week before the trip to plan day-to-day activities and discuss background geologic information. Students selected a research topic related to our itinerary and wrote a guidebook entry for the topic. Students' entries were combined with papers, maps, and background material to make a guidebook. The printed guidebooks provided students with a "publication" of their work to show to others and refer to in the field. The nine-day field trip started with a flight into Las Vegas, NV, on 3/1/14. We spent three nights camping at the South Rim of the Grand Canyon, one night camping in Valley of Fire State Park (VOFSP, 55 mi N of Las Vegas), and three nights staying at the Shoshone Education and Research Center (SHEAR) east of Death Valley. Highlights of the trip included the hike along the Bright Angel Trail (and fault) to Plateau Point and recognition of the Great Unconformity at GCNP; the White Domes loop hike, camping at the Beehives, and observation of the Muddy Mountain Overthrust in VOFSP; and hikes at Ubehebe Crater, Badwater Salt Flat, and Natural Bridge Canyon in DVNP. Each student presented his/her research topic at a pertinent point in the field trip; students were impressively well-prepared. One requirement of the course was a poster presentation on each student's research topic at our Undergraduate Research Symposium in April. For most of the students, the poster session was the first experience preparing and presenting a poster. In addition, the class gave a joint colloquium presentation to several hundred science majors and a number of science faculty at Saint Rose. Each student spoke for five

Electric field-induced valley degeneracy lifting in uniaxial strained graphene: Evidence from magnetophonon resonance

Science.gov (United States)

Assili, Mohamed; Haddad, Sonia; Kang, Woun

2015-03-01

A double peak structure in the magnetophonon resonance (MPR) spectrum of uniaxial strained graphene, under crossed electric and magnetic fields, is predicted. We focus on the Γ point optical phonon modes coupled to the inter-Landau level transitions 0 ⇆±1 where MPR is expected to be more pronounced at high magnetic field. We derive the frequency shifts and the broadenings of the longitudinal and transverse optical phonon modes taking into account the effect of the strain modified electronic spectrum on the electron-phonon coupling. We show that the MPR line for a given phonon mode acquires a double peak structure originating from the twofold valley degeneracy lifting. The latter is due to the different Landau level spacings in the two Dirac valleys resulting from the simultaneous action of the inplane electric field and the strain-induced Dirac cone tilt. We discuss the role of some key parameters such as disorder, strain, doping, and electric field amplitude on the emergence of the double peak structure.

Water savings from reduced alfalfa cropping in California's Upper San Joaquin Valley

Science.gov (United States)

Singh, K. K.; Gray, J.

2017-12-01

Water and food and forage security are inextricably linked. In fact, 90% of global freshwater is consumed for food production. Food demand increases as populations grow and diets change, making water increasingly scarce. This tension is particularly acute, contentious, and popularly appreciated in California's Central Valley, which is one of the most important non-grain cropping areas in the United States. While the water-intensive production of tree nuts like almonds and pistachios has received the most popular attention, it is California's nation-leading alfalfa production that consumes the most water. Alfalfa, the "Queen of Forages" is the preferred feedstock for California's prodigious dairy industry. It is grown year-round, and single fields can be harvested more than four times a year; a practice which can require in excess of 1.5 m of irrigation water. Given the water scarcity in the region, the production of alfalfa is under increasing scrutiny with respect to long-term sustainability. However, the potential water savings associated with alternative crops, and various levels of alfalfa replacement have not been quantified. Here, we address that knowledge gap by simulating the ecohydrology of the Upper San Joaquin's cropping system under various scenarios of alfalfa crop replacement with crops of comparable economic value. Specifically, we use the SWAT model to evaluate the water savings that would be realized at 33%, 66%, and 100% alfalfa replacement with economically comparable, but more water efficient crops such as tomatoes. Our results provide an important quantification of the potential water savings under alternative cropping systems that, importantly, also addresses the economic concerns of farmers. Results like these provide critical guidance to farmers and land/water decision makers as they plan for a more sustainable and productive agricultural future.

Climate influences on upper Limpopo River flow

African Journals Online (AJOL)

2016-01-01

Jan 1, 2016 ... Keywords: Limpopo Valley, hydro-meteorology, surface water deficit. * To whom all ... millenia and there is a history of drought impacts on vegetation. (Ekblom et ... water budget of the upper Limpopo River valley using direct.

Bibliography of literature pertaining to Long Valley Caldera and associated volcanic fields

Science.gov (United States)

Ewert, John W.; Harpel, Christopher J.; Brooks, Suzanna K.; Marcaida, Mae

2011-01-01

define the beginning of the Brunhes Chron and helps constrain the Brunhes-Matuyama boundary. The Bishop ash, which was dispersed as far east as Nebraska, Kansas, and Texas, provides an important tephrostratigraphic marker throughout the Western United States. The obsidian domes of both the Mono and Inyo Craters, which were produced by rhyolitic eruptions in the past 40,000 years, have been well studied, including extensive scientific drilling through the domes. Exploratory drilling to 3-km depth on the resurgent dome and subsequent instrumentation of the Long Valley Exploratory Well (LVEW) have led to a number of important new insights. Scientific drilling also has been done within the Casa Diablo geothermal field, which, aside from drilling, has been commercially developed and is currently feeding 40 MW of power into the Southern California Edison grid. Studies in all the above-mentioned volcanic fields have contributed to the extensive scientific literature published on the Long Valley region. Although most of this scientific literature has been published since 1970, a significant amount of historical literature extends backward to the late 1800s. The purpose of this bibliography is to compile references pertaining to the Long Valley region from all time periods and all Earth science fields into a single listing, thus providing an easily accessible guide to the published literature for current and future researchers.

The deep thermal field of the Upper Rhine Graben

Science.gov (United States)

Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias

2017-01-01

The Upper Rhine Graben has a significant socioeconomic relevance as it provides a great potential for geothermal energy production. The key for the utilisation of this energy resource is to understand the controlling factors of the thermal field in this area. We have therefore built a data-based lithospheric-scale 3D structural model of the Upper Rhine Graben and its adjacent areas. In addition, 3D gravity modelling was performed to constrain the internal structure of the crystalline crust consistent with seismic information. Based on this lithosphere scale 3D structural model the present-day conductive thermal field was calculated and compared to measured temperatures. Our results show that the regional thermal field is mainly controlled by the configuration of the upper crust, which has different thermal properties characteristic for the Variscan and Alpine domains. Temperature maxima are predicted for the Upper Rhine Graben where thick insulating Cenozoic sediments cause a thermal blanketing effect and where the underlying crustal units are characterised by high radiogenic heat production. The comparison of calculated and measured temperatures overall shows a reasonable fit, while locally occuring model deviations indicate where a larger influence of groundwater flow may be expected.

Landsat Evapotranspiration for Historical Field-scale Water Use (1984-2015) in the Upper Rio Grande River Basin

Science.gov (United States)

Senay, G. B.; Schauer, M.; Singh, R. K.; Friedrichs, M.

2017-12-01

Field-scale water use maps derived from evapotranspiration (ET) can characterize water use patterns and the impacts of water management decisions. This project generated historical (1984-2015) Landsat-based ET maps for the entire Upper Rio Grande basin which makes this one of the largest regions in the United States with remotely sensed historical ET at Landsat resolution. More than 10,000 Landsat images spanning 32 years were processed using the Operational Simplified Surface Energy Balance (SSEBop) model which integrates weather data and remotely sensed images to estimate monthly and annual ET. Time-series analysis focused on three water-intensive study areas within the basin: the San Luis Valley in Colorado, irrigated fields along the Rio Grande River near Albuquerque, NM, and irrigated fields near Las Cruces, NM. Preliminary analysis suggests land use changes result in declining water use in irrigated areas of the basin which corresponds with increases in land surface temperatures. Time-series analysis of water use patterns at multiple temporal and spatial scales demonstrates the impact of water management decisions on the availability of water in the basin. Comparisons with cropland data from the USDA (NASS CDL) demonstrate how water use for particular crop types changes over time in response to land use changes and shifts in water management. This study illustrates a useful application of "Big Data" earth observation science for quantifying impacts of climate and land use changes on water availability within the United States as well as applications in planning water resource allocation, managing water rights, and sustaining agricultural production in the Upper Rio Grande basin.

Upper bound of abutment scour in laboratory and field data

Science.gov (United States)

Benedict, Stephen

2016-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a field investigation of abutment scour in South Carolina and used those data to develop envelope curves that define the upper bound of abutment scour. To expand on this previous work, an additional cooperative investigation was initiated to combine the South Carolina data with abutment scour data from other sources and evaluate upper bound patterns with this larger data set. To facilitate this analysis, 446 laboratory and 331 field measurements of abutment scour were compiled into a digital database. This extensive database was used to evaluate the South Carolina abutment scour envelope curves and to develop additional envelope curves that reflected the upper bound of abutment scour depth for the laboratory and field data. The envelope curves provide simple but useful supplementary tools for assessing the potential maximum abutment scour depth in the field setting.

27 CFR 9.216 - Upper Mississippi River Valley.

Science.gov (United States)

2010-04-01

...), east of St. Paul at Oakbury in Washington County. From the beginning point, proceed east on Interstate... Winnebago County to U.S. Highway 20 at Cherry Valley; then (6) Proceed west on U.S. Highway 20 to Illinois...), south of St. Paul; then (15) Follow Interstate Highway 494 (beltway) northeast into Washington County...

Solving the Upper Valley's housing needs: how a coalition of public and private organizations joined forces to develop housing in a region with inadequate stock and prohibitive prices

OpenAIRE

Dan French

2004-01-01

Like many communities, New Hampshire and Vermont's Upper Valley region is facing a serious housing shortage. Dan French reveals how an innovative housing coalition is working to find solutions that provide housing and protect the area's quality of life.

Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

Science.gov (United States)

Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

2009-01-01

Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

Gold mineralisation near the Main Divide, upper Wilberforce valley, Southern Alps, New Zealand

International Nuclear Information System (INIS)

Becker, J.A.; Craw, D.; Horton, T.; Chamberlain, C.P.

2000-01-01

Veins up to 8 m wide fill extensional fractures in Torlesse Terrane metasediments near the Main Divide in the upper Wilberforce valley, Canterbury, New Zealand. The upper Wilberforce veins are part of a prominent 40 km long, NNE-trending swarm of gold-bearing veins formed across the Main Divide during the Late Cenozoic rise of the Southern Alps. The veins occur within, and near, a prominent set of faults which constitute the Main Divide Fault Zone. The veins are irregular in shape due to contrasting host rock properties, and have been only weakly sheared and deformed. Veins cut across greywacke beds and follow irregularly along argillite beds, on the 1-10 m scale. Quartz dominates vein mineralogy, but albite forms up to 45% of some veins, and minor chlorite, pyrite, arsenopyrite, chalcopyrite, and gold occur sporadically, especially in breccias near vein margins. Fluid inclusions in vein quartz homogenise at 180-253 degrees C, and arsenopyrite composition (28.3-30.8 at.% As) suggest formation temperatures of 250-350 degrees C. Elevated arsenic levels (up to 200 ppm above a background of 10 ppm) in some host greywackes and argellites suggest that hydrothermal activity pervaded host rocks as well as forming veins, but there is no textural evidence for this fluid flow. Late-stage carbonates in faults adjacent to the quartz veins, but which postdate the quartz veins, have δ 18 O ranging from 11.1 to 25.6 per thousand, and δ 13 C ranging from -12.5 to -1.1 per thousand. These carbonates were deposited by a mixture of meteoric and crustally isotopically exchanged fluid as a shallow-level manifestation of the same hydrothermal system which deposited the quartz veins. The upper Wilberforce veins structurally and mineralogically resemble some Late Cenozoic gold-bearing vein systems in the Mt Cook area, 100 km to the southwest along the Southern Alps. (author). 52 refs., 9 figs., 3 tabs

Changes in the status of harvested rice fields in the Sacramento Valley, California: Implications for wintering waterfowl.

Science.gov (United States)

Miller, Michael R.; Garr, Jay D.; Coates, Peter S.

2010-01-01

Harvested rice fields provide critical foraging habitat for wintering waterfowl in North America, but their value depends upon post-harvest treatments. We visited harvested ricefields in the Sacramento Valley, California, during the winters of 2007 and 2008 (recent period) and recorded their observed status as harvested (standing or mechanically modified stubble), burned, plowed, or flooded. We compared these data with those from identical studies conducted during the 1980s (early period). We documented substantial changes in field status between periods. First, the area of flooded rice increased 4-5-fold, from about 15% to >40% of fields, because of a 3-4-fold increase in the percentage of fields flooded coupled with a 37-41% increase in the area of rice produced. Concurrently, the area of plowed fields increased from 35% of fields, burned fields declined from about 40% to 1%, and fields categorized as harvested declined from 22-54% to rice field status survey in the Sacramento Valley and other North American rice growing regions as appropriate to support long-term monitoring programs and wetland habitat conservation planning for wintering waterfowl.

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

Science.gov (United States)

Lu, Wei-Tao

2016-08-01

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

Alpine ethnobotany in Italy: traditional knowledge of gastronomic and medicinal plants among the Occitans of the upper Varaita valley, Piedmont.

Science.gov (United States)

Pieroni, Andrea; Giusti, Maria Elena

2009-11-06

A gastronomic and medical ethnobotanical study was conducted among the Occitan communities living in Blins/Bellino and Chianale, in the upper Val Varaita, in the Piedmontese Alps, North-Western Italy, and the traditional uses of 88 botanical taxa were recorded. Comparisons with and analysis of other ethnobotanical studies previously carried out in other Piemontese and surrounding areas, show that approximately one fourth of the botanical taxa quoted in this survey are also known in other surrounding Occitan valleys. It is also evident that traditional knowledge in the Varaita valley has been heavily eroded. This study also examined the local legal framework for the gathering of botanical taxa, and the potential utilization of the most quoted medicinal and food wild herbs in the local market, and suggests that the continuing widespread local collection from the wild of the aerial parts of Alpine wormwood for preparing liquors (Artemisia genipi, A. glacialis, and A. umbelliformis) should be seriously reconsidered in terms of sustainability, given the limited availability of these species, even though their collection is culturally salient in the entire study area.

Granitoids of the Dry Valleys area, southern Victoria Land, Antarctica : plutons, field relationships, and isotopic dating

International Nuclear Information System (INIS)

Allibone, A.H.; Cox, S.C.; Johnstone, R.D.

1993-01-01

Detailed mapping throughout much of the Dry Valleys area indicates the region is underlain by 15 major granitoid plutons and numerous smaller plugs and dikes. Intrusive relationships of these plutons and dikes indicate repeated intrusion of superficially similar granitoids at different times. Sufficient internal lithologic variation occurs within individual plutons, to allow correlation with several of the previously defined granitoid units based on lithologic character. Consequently, previous subdivision schemes based on lithology are no longer tenable and are here replaced with a subdivision scheme based on the identification of individual plutons. The elongate, concordant Bonney, Denton, Cavendish, and Wheeler Plutons, which range in composition between monzodiorite and granodiorite, are the oldest relatively undeformed plutons in the Dry Valleys area. Each pluton is characterised by flow alignment of K-feldspar megacrysts, hornblende, biotite, and mafic enclaves. Field relationships and radiometric dating indicate these are deep-level plutons, emplaced synchronous with upper amphibolite facies metamorphism of the adjacent Koettlitz Group between 589 and 490 Ma ago. Elongate, discordant plutons of equigranular homogeneous biotite granodiorite and granite (Hedley, Valhalla, St Johns, Suess) were subsequently emplaced by stoping at a relatively high crustal level at 490 Ma. These eight plutons are cut by numerous swarms of Vanda mafic and felsic porphyry dikes. The ovoid, discordant, high level Pearse, Nibelungen, Orestes, Brownworth, Swinford, and Harker Plutons, emplaced between c. 486 and 477 Ma, display mutually crosscutting relationships with the youngest of the Vanda dikes. These younger plutons range in composition between monzonite and granite. Some are characterised by K-feldspar megacrystic textures superficially similar to some of the oldest concordant plutons. (author). 57 refs.; 2 tabs.; 4 figs

Ganges Valley Aerosol Experiment: Science and Operations Plan

Energy Technology Data Exchange (ETDEWEB)

Kotamarthi, VR

2010-06-21

The Ganges Valley region is one of the largest and most rapidly developing sections of the Indian subcontinent. The Ganges River, which provides the region with water needed for sustaining life, is fed primarily by snow and rainfall associated with Indian summer monsoons. Impacts of changes in precipitation patterns, temperature, and the flow of the snow-fed rivers can be immense. Recent satellite-based measurements have indicated that the upper Ganges Valley has some of the highest persistently observed aerosol optical depth values. The aerosol layer covers a vast region, extending across the Indo-Gangetic Plain to the Bay of Bengal during the winter and early spring of each year. The persistent winter fog in the region is already a cause of much concern, and several studies have been proposed to understand the economic, scientific, and societal dimensions of this problem. During the INDian Ocean EXperiment (INDOEX) field studies, aerosols from this region were shown to affect cloud formation and monsoon activity over the Indian Ocean. This is one of the few regions showing a trend toward increasing surface dimming and enhanced mid-tropospheric warming. Increasing air pollution over this region could modify the radiative balance through direct, indirect, and semi-indirect effects associated with aerosols. The consequences of aerosols and associated pollution for surface insolation over the Ganges Valley and monsoons, in particular, are not well understood. The proposed field study is designed for use of (1) the ARM Mobile Facility (AMF) to measure relevant radiative, cloud, convection, and aerosol optical characteristics over mainland India during an extended period of 9–12 months and (2) the G-1 aircraft and surface sites to measure relevant aerosol chemical, physical, and optical characteristics in the Ganges Valley during a period of 6–12 weeks. The aerosols in this region have complex sources, including burning of coal, biomass, and biofuels; automobile

Prokaryotic Abundance and Activity in Permafrost of the Northern Victoria Land and Upper Victoria Valley (Antarctica).

Science.gov (United States)

La Ferla, Rosabruna; Azzaro, Maurizio; Michaud, Luigi; Caruso, Gabriella; Lo Giudice, Angelina; Paranhos, Rodolfo; Cabral, Anderson S; Conte, Antonella; Cosenza, Alessandro; Maimone, Giovanna; Papale, Maria; Rappazzo, Alessandro Ciro; Guglielmin, Mauro

2017-08-01

Victoria Land permafrost harbours a potentially large pool of cold-affected microorganisms whose metabolic potential still remains underestimated. Three cores (BC-1, BC-2 and BC-3) drilled at different depths in Boulder Clay (Northern Victoria Land) and one sample (DY) collected from a core in the Dry Valleys (Upper Victoria Valley) were analysed to assess the prokaryotic abundance, viability, physiological profiles and potential metabolic rates. The cores drilled at Boulder Clay were a template of different ecological conditions (different temperature regime, ice content, exchanges with atmosphere and with liquid water) in the same small basin while the Dry Valleys site was very similar to BC-2 conditions but with a complete different geological history and ground ice type. Image analysis was adopted to determine cell abundance, size and shape as well as to quantify the potential viable and respiring cells by live/dead and 5-cyano-2,3-ditolyl-tetrazolium chloride staining, respectively. Subpopulation recognition by apparent nucleic acid contents was obtained by flow cytometry. Moreover, the physiological profiles at community level by Biolog-Ecoplate™ as well as the ectoenzymatic potential rates on proteinaceous (leucine-aminopeptidase) and glucidic (ß-glucosidase) organic matter and on organic phosphates (alkaline-phosphatase) by fluorogenic substrates were tested. The adopted methodological approach gave useful information regarding viability and metabolic performances of microbial community in permafrost. The occurrence of a multifaceted prokaryotic community in the Victoria Land permafrost and a large number of potentially viable and respiring cells (in the order of 10 4 -10 5 ) were recognised. Subpopulations with a different apparent DNA content within the different samples were observed. The physiological profiles stressed various potential metabolic pathways among the samples and intense utilisation rates of polymeric carbon compounds and carbohydrates

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-05-01

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

Upper critical field of Mo-Ni heterostructures

International Nuclear Information System (INIS)

Uher, C.; Watson, W.J.; Cohn, J.L.; Schuller, I.K.

1985-12-01

Upper critical field and its anisotropy have been measured on two very short wavelength Mo-Ni heterostructures of different degrees of perfection, lambda = 13.8A (disordered structure) and lambda = 16.6A (layered structure). In both cases the parallel critical field has an unexpected temperature dependence, a large and temperature dependent anisotropy, and over 60% enhancement over the Clogston-Chandrasekhar limit. Data are fit to the Werthamer-Helfand-Hohenberg theory and the spin-orbit scattering times are found to be 1.79 x 10 -13 s and 2 x 10 -13 s, respectively

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

International Nuclear Information System (INIS)

Schaer, D.W.

1981-07-01

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

Virus incidence in orchardgrass (Dactylis glomerata L.) seed production fields in the Willamette Valley

Science.gov (United States)

A survey was conducted over the course of three years (2014-2016) for the presence of Barley yellow dwarf virus (BYDV-MAV and BYDV-PAV), Cereal yellow dwarf virus (CYDV-RPV), and Cocksfoot mottle virus (CfMV) in orchardgrass (Dactylis glomerata) fields in the Willamette Valley, Oregon. There was an ...

Geochemistry and mineralogy of late Quaternary loess in the upper Mississippi River valley, USA: Provenance and correlation with Laurentide Ice Sheet history

Science.gov (United States)

Muhs, Daniel; Bettis, E. Arthur; Skipp, Gary L.

2018-01-01

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from diverse geologic terrains in North America. Further, different loess bodies that are known to have had the same source sediments (using other criteria) have similar K/Rb and K/Ba values. We also studied three thick loess sections in the upper Mississippi River valley region. At each site, the primary composition of the loess changed over the course of the last glacial period, and K/Rb and K/Ba values parallel changes in carbonate mineral content and clay mineralogy. We thus confirm conclusions of earlier investigators that loess composition changed as a result of the shifting dominance of different lobes of the Laurentide Ice Sheet and the changing course of the Mississippi River. We conclude that K/Rb and K/Ba values are effective, robust, and rapid indicators of loess provenance that can be applied to many regions of the world.

Geochemistry and mineralogy of late Quaternary loess in the upper Mississippi River valley, USA: Provenance and correlation with Laurentide Ice Sheet history

Science.gov (United States)

Muhs, Daniel R.; Bettis, E. Arthur; Skipp, Gary L.

2018-05-01

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from diverse geologic terrains in North America. Further, different loess bodies that are known to have had the same source sediments (using other criteria) have similar K/Rb and K/Ba values. We also studied three thick loess sections in the upper Mississippi River valley region. At each site, the primary composition of the loess changed over the course of the last glacial period, and K/Rb and K/Ba values parallel changes in carbonate mineral content and clay mineralogy. We thus confirm conclusions of earlier investigators that loess composition changed as a result of the shifting dominance of different lobes of the Laurentide Ice Sheet and the changing course of the Mississippi River. We conclude that K/Rb and K/Ba values are effective, robust, and rapid indicators of loess provenance that can be applied to many regions of the world.

Geologic field-trip guide to Long Valley Caldera, California

Science.gov (United States)

Hildreth, Wes; Fierstein, Judy

2017-07-26

This guide to the geology of Long Valley Caldera is presented in four parts: (1) An overview of the volcanic geology; (2) a chronological summary of the principal geologic events; (3) a road log with directions and descriptions for 38 field-trip stops; and (4) a summary of the geophysical unrest since 1978 and discussion of its causes. The sequence of stops is arranged as a four-day excursion for the quadrennial General Assembly of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), centered in Portland, Oregon, in August 2017. Most stops, however, are written freestanding, with directions that allow each one to be visited independently, in any order selected.

A valley-filtering switch based on strained graphene.

Science.gov (United States)

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

2011-09-28

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

A valley-filtering switch based on strained graphene

International Nuclear Information System (INIS)

Zhai Feng; Ma Yanling; Zhang Yingtao

2011-01-01

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

Salinity Trends in the Upper Colorado River Basin Upstream From the Grand Valley Salinity Control Unit, Colorado, 1986-2003

Science.gov (United States)

Leib, Kenneth J.; Bauch, Nancy J.

2008-01-01

Salinity Control Unit was 10,700 tons/year. This accounts for approximately 27 percent of the decrease observed downstream from the Grand Valley Salinity Control Unit. Salinity loads were decreasing at the fastest rate (6,950 tons/year) in Region 4, which drains an area between the Colorado River at Cameo, Colorado (station CAMEO) and Colorado River above Glenwood Springs, Colorado (station GLEN) streamflow-gaging stations. Trends in salinity concentration and streamflow were tested at station CAMEO to determine if salinity concentration, streamflow, or both are controlling salinity loads upstream from the Grand Valley Salinity Control Unit. Trend tests of individual ion concentrations were included as potential indicators of what sources (based on mineral composition) may be controlling trends in the upper Colorado. No significant trend was detected for streamflow from 1986 to 2003 at station CAMEO; however, a significant downward trend was detected for salinity concentration. The trend slope indicates that salinity concentration is decreasing at a median rate of about 3.54 milligrams per liter per year. Five major ions (calcium, magnesium, sodium, sulfate, and chloride) were tested for trends. The results indicate that processes within source areas with rock and soil types (or other unidentified sources) bearing calcium, sodium, and sulfate had the largest effect on the downward trend in salinity load upstream from station CAMEO. Downward trends in salinity load resulting from ground-water sources and/or land-use change were thought to be possible reasons for the observed decreases in salinity loads; however, the cause or causes of the decreasing salinity loads are not fully understood. A reduction in the amount of ground-water percolation from Region 4 (resulting from work done through Federal irrigation system improvement programs as well as privately funded irrigation system improvements) has helped reduce annual salinity load from Region 4 by approxima

Utah Valley University Field Station at Capitol Reef National Park: A Venue for Improved Student Learning and Retention

Science.gov (United States)

Nielsen, K.; Schultz, M.; Williams, B.; Gay, J.; Johnson, S.; Dunn, P.

2015-12-01

The unique geo-environment offered in Capitol Reef National Park and its surrounding areas has a long-standing history of inspiring geological scientific exploration. The Capitol Reef Field Station was established in 2008 as part of collaboration between the National Park and Utah Valley University in order to support teaching and research of the natural environment found within the park and on the Colorado Plateau. The facility itself situated deep within the park, well off any public road system offers state of the art alternative energy and sustainable construction and makes extensive use of passive heating and cooling, in order to maintain its status of being "off-grid." The field station is a 6200 square foot complex of classrooms and dormitories supporting university level education and field studies of the Colorado Plateau. The complex includes a classroom and dining area, professional kitchen, and two separate dormitories, which can sleep up to 24 overnight visitors, while the daytime usage can accommodate up to 40 visitors. The vision of the facility is to support teaching and research toward responsible, respectful, and sustainable stewardship of the natural world - including Interdisciplinary learning between arts and sciences Student internships and service learning in collaboration with the National Park Service Field-based scientific research (as well as inventorying and assessing Park ecosystems changes) Field training in scientific research Collaboration between National Park Service scientists and local, regional, and national institutions The park is situated at 38°N 249°E at elevations greater than 2000 m in Southern Utah. In contrast to the more famous neighboring sister parks such as Zion and Bryce Canyon National Parks, which are in relatively close proximity to large road systems and cities, Capitol Reef offers what is believed to be the darkest night sky in the US. The culmination of features creates an ideal location for studies of the

Lattice-induced double-valley degeneracy lifting in graphene by a magnetic field.

Science.gov (United States)

Luk'yanchuk, Igor A; Bratkovsky, Alexander M

2008-05-02

We show that the recently discovered double-valley splitting of the Landau levels in the quantum Hall effect in graphene can be explained as the perturbative orbital interaction of intravalley and intervalley microscopic orbital currents with a magnetic field. This effect is facilitated by the translationally noninvariant terms that correspond to graphene's crystallographic honeycomb symmetry but do not exist in the relativistic theory of massless Dirac fermions in quantum electrodynamics. We discuss recent data in view of these findings.

Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

Science.gov (United States)

Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

2015-12-01

Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

New simple mathematical model to help evaluating the extent of the late-Quaternary valley glacier in the Upper Soča Region (NW Slovenia

Directory of Open Access Journals (Sweden)

Miloš Bavec

2002-06-01

Full Text Available A simple mathematical model was developed that enables an evaluation of a valley glacier extent independently of any geological data. Based on glaciological criteria and on quantitative analysis of the glacier’s accumulation-, and ablation-areas the modeloffers an opportunity for an independent test of paleoenvironmental interpretations that are traditionally based on (often vague and difficult-to-interpret geomorphological and sedimentological information. The model is presented here through a case study from theUpper Soča River Region.

Holocene landscape evolution of the Havelock and Upper Rangitata valleys, South Canterbury, New Zealand

International Nuclear Information System (INIS)

Forsyth, P.J.; Barrell, D.J.A.; Basher, L.R.; Berryman, K.R.

2003-01-01

Erosion in the Havelock Valley and upper Rangitata River is dominated by fluvial and mass movement processes. Active floodplains, alluvial fans and debris cones are prominent features of the landscape. Several rock avalanche deposits also occur in the area. A search for dateable deposits yielded materials and surfaces whose ages were estimated by several methods. Weathering rind ages ranged from 10,000 to 297 ± 75 years, and calibrated radiocarbon ages from 14,941 ± 712 to 151 ± 146 years BP. Rhizocarpon species lichen measurements yielded various ages depending on which lichen growth curve was used, but are probably useful only for surfaces up to about 250 years old. Buried and surface soil characteristics, though not giving a numerical age, were generally consistent with ages derived by other methods. The dated deposits record periods of stability separated by episodes of aggradation. However, the hypothesis that Alpine Fault earthquakes may create visible signals in the landscape was not confirmed. Rock avalanche deposits, alluvial fans and debris cones were examined, and yielded various types of age data, but none were related with certainty to known earthquake events. (author). 32 refs., 21 figs., 4 tabs

The Passy-2015 field experiment: wintertime atmospheric dynamics and air quality in a narrow alpine valley

Science.gov (United States)

Paci, Alexandre; Staquet, Chantal

2016-04-01

Wintertime anticyclonic conditions lead to the formation of persistent stable boundary layers which may induce severe air pollution episodes in urban or industrialized area, particularly in mountain regions. The Arve river valley in the Northern Alps is very sensitive to this phenomenon, in particular close to the city of Passy (Haute-Savoie), 20 km down valley past Chamonix. This place is indeed one of the worst place in France regarding air quality, the concentration of fine particles and Benzo(a)pyrene (a carcinogenic organic compound) regularly exceeding the EU legal admissible level during winter. Besides air quality measurements, such as the ones presently carried in the area by the local air quality agency Air Rhône-Alpes or in the DECOMBIO project led by LGGE, it is crucial to improve our knowledge of the atmospheric boundary layer dynamics and processes at the valley scale under these persistent stable conditions in order to improve our understanding on how it drives pollutant dispersion. These issues motivated the Passy-2015 field experiment which took place during the winter 2014-2015. A relatively large set-up of instruments was deployed on a main measurement site in the valley center and on four other satellite sites. It includes several remote sensing instruments, a surface flux station, a 10 m instrumented tower, a large aperture scintillometer, a fog monitoring station among others. Most of the instruments were present from early January to the end of February. During two intensive observation periods, 6-14 February and 17-20 February, the instrumental set-up was completed on the main site with high frequency radio-soundings (up to one per 1h30), a tethered balloon, a remote controlled drone quadcopter and a sodar. The field campaign, the instruments, the meteorological situations observed and preliminary results will be presented. This field experiment is part of the Passy project funded by ADEME through the French national programme LEFE/INSU and

Valley and spin thermoelectric transport in ferromagnetic silicene junctions

International Nuclear Information System (INIS)

Ping Niu, Zhi; Dong, Shihao

2014-01-01

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

Electrical control of the anomalous valley Hall effect in antiferrovalley bilayers

Science.gov (United States)

Tong, Wen-Yi; Duan, Chun-Gang

2017-08-01

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

Maize yield response to residual soil moisture In inland valley of ...

African Journals Online (AJOL)

Two sets of experiments were conducted in three replicates each on both upper and lower fringes of Minna inland valley, Niger State, Nigeria. While the upper fringe was subjected to surface irrigation the residual moisture in the lower fringe provided the maize crop with all water requirements from planting to maturity.

Monte Carlo simulation of THz radiation from GaAs p-i-n diodes under high electric fields using an extended valley model

International Nuclear Information System (INIS)

Dinh Nhu Thao

2008-01-01

We have applied a self-consistent ensemble Monte Carlo simulation procedure using an extended valley model to consider the THz radiation from GaAs p-i-n diodes under high electric fields. The present calculation has shown an important improvement of the numerical results when using this model instead of the usual valley model. It has been shown the importance of the full band-structure in the simulation of processes in semiconductors, especially under the influence of high electric fields. (author)

Enhanced upper critical fields in binary Nb-Ti alloys

International Nuclear Information System (INIS)

Hariharan, Y.; Sastry, V.S.; Janawadkar, M.P.; Radhakrishnan, T.S.

1986-01-01

The authors report the enhancement of H/sub c2/ in quenched and suitably heat treated binary Nb-65 at % Ti alloys. The inherent metastability of the bcc β phase and its instability towards athermal ω are used to realise high values of normal state resistivity ε/sub n/. The consequences of this on the upper critical field have been experimentally determined by the measurement of dH/sub c2//dT at T/sub c/ and of T/sub c/. These together with our similar measurements on Nb-83 at % Ti alloy to which at 1 at % N was added (to retain it in the β phase) are analysed in terms of the existing theories for upper critical fields. It is shown that a peak in H/sub c2/(o) occurs at 17 - 18 T when ε/sub n/ has a value of approximately 100 μΩcm

Green River air quality model development: meteorological and tracer data, July/August 1982 field study in Brush Valley, Colorado

Energy Technology Data Exchange (ETDEWEB)

Whiteman, C.D.; Lee, R.N.; Orgill, M.M.; Zak, B.D.

1984-06-01

Meteorological and atmospheric tracer studies were conducted during a 3-week period in July and August of 1982 in the Brush Creek Valley of northwestern Colorado. The objective of the field experiments was to obtain data to evaluate a model, called VALMET, developed at PNL to predict dispersion of air pollutants released from an elevated stack located within a deep mountain valley in the post-sunrise temperature inversion breakup period. Three tracer experiments were conducted in the valley during the 2-week period. In these experiments, sulfur hexafluoride (SF/sub 6/) was released from a height of approximately 100 m, beginning before sunrise and continuing until the nocturnal down-valley winds reversed several hours after sunrise. Dispersion of the sulfur hexafluoride after release was evaluated by measuring SF/sub 6/ concentrations in ambient air samples taken from sampling devices operated within the valley up to about 8 km down valley from the source. An instrumented research aircraft was also used to measure concentrations in and above the valley. Tracer samples were collected using a network of radio-controlled bag sampling stations, two manually operated gas chromatographs, a continuous SF/sub 6/ monitor, and a vertical SF/sub 6/ profiler. In addition, basic meteorological data were collected during the tracer experiments. Frequent profiles of vertical wind and temperature structure were obtained with tethered balloons operated at the release site and at a site 7.7 km down the valley from the release site. 10 references, 63 figures, 50 tables.

Exploring Controls on Sinuousity, Terraces and River Capture in the Upper Dajia River, Taiwan

Science.gov (United States)

Belliveau, L. C.; Ouimet, W. B.; Chan, Y. C.; Byrne, T. B.

2015-12-01

Taiwan is one of the most tectonically active regions in the world and is prone to landslides due to steep topography, large earthquakes and frequent typhoons. Landslides often affect and alter the river valleys beneath them, producing knickpoints on longitudinal river profiles, segmenting valleys into mixed bedrock-alluvial rivers and affecting river incision for tens to thousands of years. This study investigates the origin and evolution of complex channel morphologies, terraces and river capture along a 20km stretch of the Upper Da-Jia River in the Heping area of Taiwan. Through GIS analysis and field studies, we explore controls on river channel sinuousity, terrace development and river capture in relation to tectonic and climatic forcing, rock erodibility and landslides. High channel sinuousity is proposed as the result of a coupling between bank erosion and landslides. We discuss three types of landslide-induced meanders and increased sinuousity: (a) depositional-push meanders, (b) failure-zone erosional meanders, and (c) complex-erosional meanders. We also investigate spatial variation in channel morphology (slope, width) and the distribution and heights of river terraces within the Upper Da-Jia watershed associated with periods of widespread valley filling from landslide activity. Examples of river capture provide further evidence of the dynamic interactions between river incision, landslides and associated changes in channel morphology and terrace development within steep rapidly uplift, eroding and evolving mountain belts.

Valley development on Hawaiian volcanoes

International Nuclear Information System (INIS)

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

1987-01-01

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

Alumina+Silica+/-Germanium Alteration in Smectite-Bearing Marathon Valley, Endeavour Crater Rim, Mars

Science.gov (United States)

Mittlefehldt, D. W.; Gellert, R.; Van Bommel, S.; Arvidson, R. E.; Clark, B. C.; Ming, D. W.; Schroeder, C.; Yen, A. S.; Fox, V. K.; Farrand, W. H.;

The upper critical field of CeCoIn5

International Nuclear Information System (INIS)

Howald, Ludovic; Knebel, Georg; Aoki, Dai; Lapertot, Gérard; Brison, Jean-Pascal

2011-01-01

We present a detailed analysis of the upper critical field for CeCoIn 5 under high pressure. We show that, consistent with other measurements, this system shows a decoupling between the maximum of the superconducting transition temperature T c and the maximum pairing strength. We propose a model in which, in order to account for the discrepancy in pressure between the maximum of the upper critical field and the maximum of T c , we introduce magnetic pair-breaking effects, already widely suggested by other measurements. We found that within the Eliashberg frame work, the unusual shape of H c2 (T) can be completely reproduced when magnetic pair breaking is taken into account. Surprisingly, we found that the maximum of pair breaking and of pair coupling coincide in pressure, suggesting that both mechanisms originate from quantum criticality. Our model implies that CeCoIn 5 is the first compound of its family that shows clear decoupling between the maximum of T c and quantum criticality. (paper)

Photon wavelength dependent valley photocurrent in multilayer MoS2

Science.gov (United States)

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

2017-12-01

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

Palms and Palm Communities in the Upper Ucayali River Valley - a Little-Known Region in the Amazon Basin

DEFF Research Database (Denmark)

Balslev, Henrik; Eiserhardt, Wolf L.; Kristiansen, Thea

2010-01-01

The Amazon region and its palms are inseparable. Palms make up such an important part of the rain forest ecosystem that it is impossible to imagine the Amazon basin without them. Palms are visible in the canopy and often fill up the forest understory. Palms – because of their edible fruits...... – are cornerstone species for the survival of many animals, and palms contribute substantially to forest inventories in which they are often among the ten most important families. Still, the palms and palm communities of some parts of the Amazon basin remain poorly studied and little known. We travelled to a little......-explored corner of the western Amazon basin, the upper Ucayali river valley. There, we encountered 56 different palms, 18 of which had not been registered for the region previously, and 21 of them were found 150–400 km beyond their previously known limits....

Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6: Salt Valley

Science.gov (United States)

1984-12-01

Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker trail formation.

The upper bound of abutment scour defined by selected laboratory and field data

Science.gov (United States)

Benedict, Stephen; Caldwell, Andral W.

2015-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a field investigation of abutment scour in South Carolina and used that data to develop envelope curves defining the upper bound of abutment scour. To expand upon this previous work, an additional cooperative investigation was initiated to combine the South Carolina data with abutment-scour data from other sources and evaluate the upper bound of abutment scour with the larger data set. To facilitate this analysis, a literature review was made to identify potential sources of published abutment-scour data, and selected data, consisting of 446 laboratory and 331 field measurements, were compiled for the analysis. These data encompassed a wide range of laboratory and field conditions and represent field data from 6 states within the United States. The data set was used to evaluate the South Carolina abutment-scour envelope curves. Additionally, the data were used to evaluate a dimensionless abutment-scour envelope curve developed by Melville (1992), highlighting the distinct difference in the upper bound for laboratory and field data. The envelope curves evaluated in this investigation provide simple but useful tools for assessing the potential maximum abutment-scour depth in the field setting.

Wetland survey of the X-10 Bethel Valley and Melton Valley groundwater operable units at Oak Ridge National Labortory Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Rosensteel, B.A.

1996-03-01

Executive Order 11990, Protection of Wetlands, (May 24, 1977) requires that federal agencies avoid, to the extent possible, adverse impacts associated with the destruction and modification of wetlands and that they avoid direct and indirect support of wetlands development when there is a practicable alternative. In accordance with Department of Energy (DOE) Regulations for Compliance with Floodplains and Wetlands Environmental Review Requirements (Subpart B, 10 CFR 1022.11), surveys for wetland presence or absence were conducted in both the Melton Valley and the Bethel Valley Groundwater Operable Units (GWOU) on the DOE Oak Ridge Reservation (ORR) from October 1994 through September 1995. As required by the Energy and Water Development Appropriations Act of 1992, wetlands were identified using the criteria and methods set forth in the Wetlands Delineation Manual (Army Corps of Engineers, 1987). Wetlands were identified during field surveys that examined and documented vegetation, soils, and hydrologic evidence. Most of the wetland boundary locations and wetland sizes are approximate. Boundaries of wetlands in Waste Area Grouping (WAG) 2 and on the former proposed site of the Advanced Neutron Source in the upper Melton Branch watershed were located by civil survey during previous wetland surveys; thus, the boundary locations and areal sizes in these areas are accurate. The wetlands were classified according to the system developed by Cowardin et al. (1979) for wetland and deepwater habitats of the United States. A total of 215 individual wetland areas ranging in size from 0.002 ha to 9.97 ha were identified in the Bethel Valley and Melton Valley GWOUs. The wetlands are classified as palustrine forested broad-leaved deciduous (PFO1), palustrine scrub-shrub broad-leaved deciduous (PSS1), and palustrine persistent emergent (PEM1)

75 FR 62137 - Notice of Intent To Collect Fees on Public Land in Fremont County, Idaho, Upper Snake Field...

Science.gov (United States)

2010-10-07

... Intent To Collect Fees on Public Land in Fremont County, Idaho, Upper Snake Field Office Under the.... SUMMARY: In accordance with the Federal Lands Recreation Enhancement Act (REA), the Upper Snake Field... months after the publication of this notice, the Upper Snake Field Office will initiate fee collection in...

Geological techniques utilized in trap Spring Field discovery, Railroad Valley, Nye County, Nevada

Energy Technology Data Exchange (ETDEWEB)

Dolly, E.D.

1980-01-01

The trap at Eagle Springs Field is a combination stratigraphic truncation-subcrop-fault trap. Production occurs from matrix and fracture porosity in reservoirs in the Sheep Pass Formation (Cretaceous and Eocene) and the Garrett Ranch volcanic group (Oligocene). Probably the most unique feature about the field is that the production occurs from the highest position on the lowermost fault block at the basin margin. On the adjacent higher fault blocks the reservoir beds were removed by erosion during the basin and range orogenic event. The position of the truncated edge of the lower Tertiary reservoir units is controlled by the fault pattern at the margin of the valley-basin Graben. Detailed geomorphic studies indicated that this fault pattern may be identified at the surface. Regional geomorphic mapping of fault patterns was conducted to localize areas with possible subcrop truncation patterns similar to Eagle Springs Field. 20 references.

The Uncanny Valley and Nonverbal Communication in Virtual Characters

DEFF Research Database (Denmark)

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

2014-01-01

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

Contribution of Soil Fauna to Foliar Litter-Mass Loss in Winter in an Ecotone between Dry Valley and Montane Forest in the Upper Reaches of the Minjiang River.

Science.gov (United States)

Peng, Yan; Yang, Wanqin; Li, Jun; Wang, Bin; Zhang, Chuan; Yue, Kai; Wu, Fuzhong

2015-01-01

Litter decomposition during winter can provide essential nutrients for plant growth in the subsequent growing season, which plays important role in preventing the expansion of dry areas and maintaining the stability of ecotone ecosystems. However, limited information is currently available on the contributions of soil fauna to litter decomposition during winter in such ecosystems. Therefore, a field experiment that included litterbags with two different mesh sizes (0.04 mm and 3 mm) was conducted to investigate the contribution of soil fauna to the loss of foliar litter mass in winter from November 2013 to April 2014 along the upper reaches of the Minjiang River. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana) and oak (Quercus baronii) in ecotone; cypress (Cupressus chengiana) and clovershrub (Campylotropis macrocarpa) in dry valley; and fir (Abies faxoniana) and birch (Betula albosinensis) in montane forest. Over one winter incubation, foliar litter lost 6.0%-16.1%, 11.4%-26.0%, and 6.4%-8.5% of initial mass in the ecotone, dry valley and montane forest, respectively. Soil fauna showed obvious contributions to the loss of foliar litter mass in all of the ecosystems. The highest contribution (48.5%-56.8%) was observed in the ecotone, and the lowest contribution (0.4%-25.8%) was observed in the montane forest. Compared with other winter periods, thawing period exhibited higher soil fauna contributions to litter mass loss in ecotone and dry valley, but both thawing period and freezing period displayed higher soil fauna contributions in montane forest. Statistical analysis demonstrated that the contribution of soil fauna was significantly correlated with temperature and soil moisture during the winter-long incubation. These results suggest that temperature might be the primary control factor in foliar litter decomposition, but more active soil fauna in the ecotone could contribute more in litter decomposition and

Contribution of Soil Fauna to Foliar Litter-Mass Loss in Winter in an Ecotone between Dry Valley and Montane Forest in the Upper Reaches of the Minjiang River.

Directory of Open Access Journals (Sweden)

Yan Peng

Full Text Available Litter decomposition during winter can provide essential nutrients for plant growth in the subsequent growing season, which plays important role in preventing the expansion of dry areas and maintaining the stability of ecotone ecosystems. However, limited information is currently available on the contributions of soil fauna to litter decomposition during winter in such ecosystems. Therefore, a field experiment that included litterbags with two different mesh sizes (0.04 mm and 3 mm was conducted to investigate the contribution of soil fauna to the loss of foliar litter mass in winter from November 2013 to April 2014 along the upper reaches of the Minjiang River. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana and oak (Quercus baronii in ecotone; cypress (Cupressus chengiana and clovershrub (Campylotropis macrocarpa in dry valley; and fir (Abies faxoniana and birch (Betula albosinensis in montane forest. Over one winter incubation, foliar litter lost 6.0%-16.1%, 11.4%-26.0%, and 6.4%-8.5% of initial mass in the ecotone, dry valley and montane forest, respectively. Soil fauna showed obvious contributions to the loss of foliar litter mass in all of the ecosystems. The highest contribution (48.5%-56.8% was observed in the ecotone, and the lowest contribution (0.4%-25.8% was observed in the montane forest. Compared with other winter periods, thawing period exhibited higher soil fauna contributions to litter mass loss in ecotone and dry valley, but both thawing period and freezing period displayed higher soil fauna contributions in montane forest. Statistical analysis demonstrated that the contribution of soil fauna was significantly correlated with temperature and soil moisture during the winter-long incubation. These results suggest that temperature might be the primary control factor in foliar litter decomposition, but more active soil fauna in the ecotone could contribute more in litter

Distribution and habitat use of king rails in the Illinois and Upper Mississippi River valleys

Science.gov (United States)

Darrah, Abigail J.; Krementz, David G.

2009-01-01

The migratory population of the king rail (Rallus elegans) has declined dramatically during the past 40 years, emphasizing the need to identify habitat requirements of this species to help guide conservation efforts. To assess distribution and habitat use of king rails along the Illinois and Upper Mississippi valleys, USA, we conducted repeated call-broadcast surveys at 83 locations in 2006 and 114 locations in 2007 distributed among 21 study sites. We detected king rails at 12 survey locations in 2006 and 14 locations in 2007, illustrating the limited distribution of king rails in this region. We found king rails concentrated at Clarence Cannon National Wildlife Refuge, an adjacent private Wetlands Reserve program site, and B. K. Leach Conservation Area, which were located in the Mississippi River floodplain in northeast Missouri. Using Program PRESENCE, we estimated detection probabilities and built models to identify habitat covariates that were important in king rail site occupancy. Habitat covariates included percentage of cover by tall (> 1 m) and short (wetlands that were characterized by high water-vegetation interspersion and little or no cover by woody vegetation. Our results suggest that biologists can improve king rail habitat by implementing management techniques that reduce woody cover and increase vegetation-water interspersion in wetlands.

A luminescence dating study of the sediment stratigraphy of the Lajia Ruins in the upper Yellow River valley, China

Science.gov (United States)

Zhang, Yuzhu; Huang, Chun Chang; Pang, Jiangli; Zhou, Yali; Zha, Xiaochun; Wang, Longsheng; Zhou, Liang; Guo, Yongqiang; Wang, Leibin

2014-06-01

Pedo-sedimentological fieldwork were carried out in the Lajia Ruins within the Guanting Basin along the upper Yellow River valley. In the eolian loess-soil sections on the second river terrace in the Lajia Ruins, we find that the land of the Qijia Culture (4.20-3.95 ka BP) are fractured by several sets of earthquake fissures. A conglomerated red clay covers the ground of the Qijia Culture and also fills in the earthquake fissures. The clay was deposited by enormous mudflows in association with catastrophic earthquakes and rainstorms. The aim of this study is to provide a luminescence chronology of the sediment stratigraphy of the Lajia Ruins. Eight samples were taken from an eolian loess-soil section (Xialajia section) in the ruins for optically stimulated luminescence (OSL) dating. The OSL ages are in stratigraphic order and range from (31.94 ± 1.99) ka to (0.76 ± 0.02) ka. Combined OSL and 14C ages with additional stratigraphic correlations, a chronological framework is established. We conclude that: (1) the second terrace of the upper part of Yellow River formed 35.00 ka ago, which was followed by the accumulation of the eolian loess-soil section; and (2) the eolian loess-soil section is composed of the Malan Loess of the late last glacial (MIS-2) and Holocene loess-soil sequences.

Simulation of channel sandstone architecture in an incised valley

Energy Technology Data Exchange (ETDEWEB)

Frykman, P.; Johannessen, P.; Andsbjerg, J.

1998-12-31

The present report describes a geostatistical modelling study that is aimed at reflecting the architecture of the channel sandstones in an incised valley fill. The example used for this study is a part of the Middle Jurassic sandy succession of the Bryne Formation in the Danish central Graben. The succession consists mainly of fluvial sediments in the lower part, overlain by tidal influenced sediments, which again is overlain by shallow marine sediments. The modelling study has been performed on a sequence of incised valley sediments in the upper part of the Bryne Formation overlying fluvial sediments. (au) EFP-96. 19 refs.

Uranium favorability of tertiary sedimentary rocks of the western Okanogan highlands and of the upper Columbia River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical analyses of samples; no known uranium deposits

Energy Technology Data Exchange (ETDEWEB)

Marjaniemi, D.K.; Robins, J.W.

1975-08-01

Tertiary sedimentary rocks in the northern portions of the western Okanogan highlands and in the upper Columbia River valley were investigated during a regional study to determine the favorability for potential uranium resources of the Tertiary sedimentary rocks of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical analyses of samples. No portion of the project area of this report is rated of high or of medium favorability for potential uranium resources. Low favorability ratings are given to Oroville, Tonasket, and Pine Creek areas of the Okanogan River valley; to the Republic graben; and to the William Lakes, Colville, and Sheep Creek areas of the upper Columbia River valley. All these areas contain some fluvial, poorly sorted feldspathic or arkosic sandstones and conglomerates. These rocks are characterized by very low permeability and a consistently high siliceous matrix suggesting very low initial permeability. There are no known uranium deposits in any of these areas, and low level uranium anomalies are rare.

Landslide susceptibility assessment in the Upper Orcia Valley (Southern Tuscany, Italy through conditional analysis: a contribution to the unbiased selection of causal factors

Directory of Open Access Journals (Sweden)

F. Vergari

2011-05-01

Full Text Available In this work the conditional multivariate analysis was applied to evaluate landslide susceptibility in the Upper Orcia River Basin (Tuscany, Italy, where widespread denudation processes and agricultural practices have a mutual impact. We introduced an unbiased procedure for causal factor selection based on some intuitive statistical indices. This procedure is aimed at detecting among different potential factors the most discriminant ones in a given study area. Moreover, this step avoids generating too small and statistically insignificant spatial units by intersecting the factor maps. Finally, a validation procedure was applied based on the partition of the landslide inventory from multi-temporal aerial photo interpretation.

Although encompassing some sources of uncertainties, the applied susceptibility assessment method provided a satisfactory and unbiased prediction for the Upper Orcia Valley. The results confirmed the efficiency of the selection procedure, as an unbiased step of the landslide susceptibility evaluation. Furthermore, we achieved the purpose of presenting a conceptually simple but, at the same time, effective statistical procedure for susceptibility analysis to be used as well by decision makers in land management.

Graphene rings in magnetic fields: Aharonov–Bohm effect and valley splitting

International Nuclear Information System (INIS)

Wurm, J; Wimmer, M; Richter, K; Baranger, H U

2010-01-01

We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe the Aharonov–Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov–Bohm oscillations are suppressed. Results for both clean (ballistic) and disordered (diffusive) rings are presented. Second, we study rings with smooth mass boundary that are weakly coupled to leads. We show that the valley degeneracy of the eigenstates in closed graphene rings can be lifted by a small magnetic flux, and that this lifting can be observed in the transport properties of the system

Critical current density and upper critical field of the PbMo6S8 Chevrel phase

International Nuclear Information System (INIS)

Seeber, B.; Decroux, M.; Fischer, O.

1988-01-01

A detailed discussion of critical current density and upper critical field for PbMo 6 S 8 (PMS) is given. It is shown that PMS bulk as well as wire samples can be prepared with sufficient quality to observe the scaling law for the volume pinning force. Using the scaling law an estimation for the critical current density as a function of field and temperature was made. The study also indicates that a substantial improvement of the critical current density can be expected by optimizing the upper critical field without changing the microstructure. It is shown that the availability of high quality samples of EuMo 6 S 8 , to which PMS is similar, makes it possible to study separately the different physical parameters which determine the upper critical field in PMS

Chemical evolution of formation waters in the Palm Valley gas field, Northern Territory

International Nuclear Information System (INIS)

Andrew, A.S.; Giblin, A.M.

2000-01-01

The chemical composition and evolution of formation waters associated with gas production in the Palm Valley field, Northern Territory, has important implications for reservoir management, saline water disposal, and gas reserve calculations. Historically, the occurrence of saline formation water in gas fields has been the subject of considerable debate. A better understanding of the origin, chemical evolution and movement of the formation water at Palm Valley has important implications for future reservoir management, disposal of highly saline water and accurate gas reserves estimation. Major and trace element abundance data suggest that a significant component of the highly saline water from Palm Valley has characteristics that may have been derived from a modified evaporated seawater source such as an evaporite horizon. The most dilute waters probably represent condensate and the variation in the chemistry of the intermediate waters suggests they were derived from a mixture of the condensate with the highly saline brine. The chemical and isotopic results raise several interrelated questions; the ultimate source of the high salinity and the distribution of apparently mixed compositions. In this context several key observation are highlighted. Strontium concentrations are extremely high in the brines; although broadly similar in their chemistry, the saline fluids are neither homogeneous nor well mixed; the 87 Sr/ 86 Sr ratios in the brines are higher than the signatures preserved in the evaporitic Bitter Springs Formation, and all other conceivably marine-related evaporites (Strauss, 1993); the 87 Sr/ 86 Sr ratios in the brines are lower than those measured from groundmass carbonates in the host rocks, and that the 87 Sr/ 86 Sr ratios of the brines are similar, but still somewhat higher than those measured in vein carbonates from the reservoir. It is concluded that the high salinity brine entered the reservoir during the Devonian uplift and was subsequently

Paramagnetic limiting of the upper critical field of the layered organic superconductor κ-(BEDT-TTF)2Cu(SCN)2

International Nuclear Information System (INIS)

Zuo, F.; Brooks, J.S.; McKenzie, R.H.; Schlueter, J.A.; Williams, J.M.

2000-01-01

We report detailed measurements of the interlayer magnetoresistance of the layered organic superconductor κ-(BEDT-TTF) 2 Cu(SCN) 2 for temperatures down to 0.5 K and fields up to 30 T. The upper critical field is determined from the resistive transition for a wide range of temperatures and field directions. For magnetic fields parallel to the layers, the upper critical field increases approximately linearly with decreasing temperature. The upper critical field at low temperatures is compared to the Pauli paramagnetic limit, at which singlet superconductivity should be destroyed by the Zeeman splitting of the electron spins. The measured value is comparable to a value for the paramagnetic limit calculated from thermodynamic quantities but exceeds the limit calculated from BCS theory. The angular dependence of the upper critical field shows a cusplike feature for fields close to the layers, consistent with decoupled layers.

Extension of the Cerro Prieto field and zones in the Mexicali Valley with geothermal possibilities in the future

Energy Technology Data Exchange (ETDEWEB)

Fonseca L, H.L.; de la Pena L, A.; Puente C, I.; Diaz C, E.

1981-01-01

This study concerns the possible extension of the Cerro Prieto field and identification of other zones in the Mexicali Valley with geothermal development potential by assessing the structural geologic conditions in relation to the regional tectonic framework and the integration of geologic and geophysical surveys carried out at Cerro Prieto. This study is based on data obtained from the wells drilled to date and the available geological and geophysical information. With this information, a geologic model of the field is developed as a general description of the geometry of what might be the geothermal reservoir of the Cerro Prieto field. In areas with geothermal potential within the Mexicali Valley, the location of irrigation wells with anomalous temperatures was taken as a point of departure for subsequent studies. Based on this initial information, gravity and magnetic surveys were made, followed by seismic reflection and refraction surveys and the drilling of 1200-m-deep multiple-use wells. Based on the results of the final integration of these studies with the geology of the region, it is suggested that the following areas should be explored further: east of Cerro Prieto, Tulecheck, Riito, Aeropuerto-Algodones, and San Luis Rio Colorado, Sonora.

Dipmeter paleocurrent determination in the Provincia Field, Middle Magdalena Valley

International Nuclear Information System (INIS)

Rubiano, J.L.

1998-01-01

For the determination of the paleocurrent directions in the Provinica Field, were took 2664 measurements of the dip meter logs were taken to make the statistical analyses of the Formations that are between Umir and the Real Group (Maastrichtian and Miocene age). The paleocurrent directions are defined based on statistics analyses, as the average (in azimuth) and its consistency ratio (CR). The paleocurrent directions are principally to the northeast for the Umir und the Lower Real Formations; to the east for the Lisama, Esmeraldas, Mugrosa, Colorado and Middle Real Formations, and in the southeast for the Upper Real Formation. In general, there were observed important changes in the paleocurrent directions between the Umir-Lisama, Lisama-Emeralds, Colorado - Real and between the medium and the upper part of the Real Group. These changes in the paleocurrent directions suggest being associated to tectonic events that involved this area

Mechanical control over valley magnetotransport in strained graphene

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-06

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

Hydrology of the Upper Malad River basin, southeastern Idaho

Science.gov (United States)

Pluhowski, Edward J.

1970-01-01

The report area comprises 485 square miles in the Basin and Range physiographic province. It includes most of eastern' Oneida County and parts of Franklin, Bannock, and Power Counties of southeastern Idaho. Relief is about 5,000 feet; the floor of the Malad Valley is at an average altitude of about 4,400 feet. Agriculture is, by far, ,the principal economic .activity. In 1960 the population of the upper Malad River basin was about 3,600, of which about 60 percent resided in Malad City, the county seat of Oneida County. The climate is semiarid throughout the Malad Valley and its principal tributary valleys; ,above 6,500 feet the climate is subhumid. Annual precipitation ranges from about 13 inches in the lower Malad Valley to more than 30 inches on the highest peaks of the Bannock and Malad ranges. Owing to ,the normally clear atmospheric conditions, large daily and seasonal temperature fluctuations are common. Topography, distance from the Pacific Ocean, .and the general atmospheric circulation are the principal factors governing the climate of the Malad River basin. The westerlies transport moisture from the P.acific Ocean toward southeastern Idaho. The north-south tren4ing mountains flanking the basin are oriented orthogonally to the moisture flux so that they are very effective in removing precipitable water from the air. A minimum uplift of 6,000 feet is required to transport moisture from the Pacific source region; accordingly, most air masses are desiccated long before they reach the Malad basin. Heaviest precipitation is generally associated with steep pressure gradients in the midtroposphere that are so oriented as to cause a deep landward penetration of moisture from the Pacific Ocean. Annual water yields in the project area range from about 0.8 inch in the, lower Malad Valley to more than 19 inches on the high peaks north and east of Malad City. The mean annual water yield for the entire basin is 4 inches, or about 115,000 acre-feet. Evaporation is

Upper critical field of complex superconducting networks in the continuum limit

International Nuclear Information System (INIS)

Santhanam, P.; Chi, C.C.

1988-01-01

We propose a simple method for calculating the superconducting upper critical field of complex periodic two-dimensional networks in the continuum limit. Two specific lattices with space groups P4gm and C2mm are used to demonstrate this approach. We obtain the result that the ratio of the critical field of these networks to that of a uniform film is close to but larger than 2

Recent Discoveries of the Paijanense in The Upper Chicama, Moche and Virú Valleys, Northern Perú: New Perspectives on the First Hunter-Gatherers in the Andes of South America

OpenAIRE

Briceño, Jesús

2014-01-01

We present newly-registered Paiján sites in the interior and upper parts of the Chicama, Moche and Virú valleys, with strong tiesto the highland region. The research indicates that Paiján hunter-gatherers were not only a coastal group whose subsistence was basedon marine resources. They also occupied diverse ecological environments preferring springs with high mobility across the Andes and exploiting diverse resources, such as white-tail deer (Odocoileus virginianus) and raw materials for pro...

Valley-orbit hybrid states in Si quantum dots

Science.gov (United States)

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

2013-03-01

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

The reservoir properties of the upper Cretaceous productive deposits at the Pravoberezhnoe field. Kollektornyye svoystva verkhnemelovykh produktivnykh otlozheniy mestorozhdeniya Pravobeiezhnoye

Energy Technology Data Exchange (ETDEWEB)

Merkulov, A.V.; Yengibarov, V.N.

1984-01-01

Based on a set of various studies, an evaluation of the type of upper Cretaceous reservoir in the Pravoberezhnoe field is given. Compared to other fields in the Chechen Ingush Autonomous Soviet Socialist Republic, the upper Cretaceous productive deposits at this field are characterized by poorer reservoir properties. The set of all data indicates that the upper Cretaceous reservoir is analogous to reservoirs of equal age in existing fields in this republic and are cavernous fissured type.

Angular dependence of the upper critical field in Bi2Sr2CuO6+δ

International Nuclear Information System (INIS)

Vedeneev, S.I.; Ovchinnikov, Yu.N.

2002-01-01

The angular dependence of the upper critical field has been investigated in a wide range of temperatures in very high-quality Bi 2 Sr 2 CuO 6+δ single crystals with critical temperature ≅ 9 K in magnetic fields up to 28 T. Although the typical value of the normal state resistivity ratio ≅ 10 4 , the anisotropy ratio of the upper critical fields is much smaller. A model is proposed based on a strong anisotropy and a small transparency between superconducting layers [ru

Effects of upper mantle heterogeneities on the lithospheric stress field and dynamic topography

Science.gov (United States)

Osei Tutu, Anthony; Steinberger, Bernhard; Sobolev, Stephan V.; Rogozhina, Irina; Popov, Anton A.

2018-05-01

The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3-D lithosphere-asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 (WSM2016) and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a seafloor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. The modeled stress field directions, using only the mantle heterogeneities below 300 km, are not perturbed much when the effects of lithosphere and crust above 300 km are added. In contrast, modeled stress magnitudes and dynamic topography are to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a good correlation of 0.51 in continents, but this correction leads to no significant improvement of the fit between the WSM2016 and the resulting lithosphere stresses. In continental regions with abundant heat flow data, TM1 results in relatively small angular misfits. For example, in western Europe the misfit between the modeled and observation-based stress is 18.3°. Our findings emphasize that the relative contributions coming from shallow and deep mantle dynamic forces are quite different for the lithospheric stress field and dynamic

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

International Nuclear Information System (INIS)

Ortiz-Monasterio, I.; Naylor, R.

2000-01-01

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

Valley Hall effect and Nernst effect in strain engineered graphene

Science.gov (United States)

Niu, Zhi Ping; Yao, Jian-ming

2018-04-01

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

Theory of the upper critical field in layered superconductors

International Nuclear Information System (INIS)

Klemm, R.A.; Luther, A.; Beasley, M.R.

1975-01-01

The upper critical field H/subc/ 2 in layered superconductors is calculated from a microscopic theory in which the electrons are assumed to propagate freely within the individual layers subject to scattering off impurities and to propagate via tunneling between the layers. For the magnetic field parallel to the layers, there is a temperature T* 2 /sub parallel/ is thus determined by the combined effects of Pauli paramagnetism and spin-orbit scattering, and for sufficiently strong spin-orbit scattering rates, H/subc/ 2 /sub parallel/(T =0) can greatly exceed the Chandrasekhar-Clogston Pauli limiting field H/subP/. This unusual behavior is found to be most pronounced in the dirty limit for the electron propagation within the layers and when the electrons scatter many times in a given layer before tunneling to an adjacent layer. Our results are also discussed in light of the available experimental data. (auth)

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

Science.gov (United States)

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

2015-01-01

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

An Upper Bound on the Entropy of Constrained 2d Fields

DEFF Research Database (Denmark)

Forchhammer, Søren; Justesen, Jørn

1998-01-01

An upper bound on the entropy of constrained 2D fields is presented. The constraints have to be symmetric in (at least) one of the two directions. The bound generalizes (in a weaker form) the bound of Calkin and Wilf (see SIAM Journal of Discrete Mathematics, vol.11, p.54-60, 1998) which is valid...

Upper critical fields in multifilamentary NbTi alloy superconducting wires

International Nuclear Information System (INIS)

Watanabe, Kazuo; Muto, Yoshio; Noto, Koshichi.

1991-01-01

In order to improve the high field performance of superconducting magnets, the upper critical field B c2 for practical multifilamentary alloy wires of NbTi, NbTiTa and NbTiHf were examined in respect with the usage of a pressurized superfluid cooling technique. The addition of Ta or Hf to NbTi enhanced by 0.5 T for B c2 at 1.8 K. Although the addition of a heavy element such as Ta or Hf has been regarded as suppressing Pauli-paramagnetism so far, it was found that the mechanism for B c2 enhancement by Hf addition is different from that by Ta addition. (author)

Hills and valleys: Understanding the under-eye

Directory of Open Access Journals (Sweden)

Milind N Naik

2016-01-01

Full Text Available Soft tissue deflation and descent have long been implicated in the pathogenesis of facial aging. In the periorbital area, the upper orbital region is thought to change by descent of the eyebrow, as well as deflation of brow fat. While the understanding of the aging changes in the upper eyelid region are relatively simple, the lower eyelid poses a myriad of aging changes, each demanding a specific management plan. These can be best described in terms of elevations, or 'Hills' and hollows, or 'Valleys'. This article simplifies the understanding of the lower eyelid in the light of anatomical knowledge, and available literature. It forms a basis of easy diagnosis and treatment of the soft tissue changes in the lower eyelid and malar region.

Origin of salinity in produced waters from the Palm Valley gas field, Northern Territory, Australia

International Nuclear Information System (INIS)

Andrew, Anita S.; Whitford, David J.; Berry, Martin D.; Barclay, Stuart A.; Giblin, Angela M.

2005-01-01

The chemical composition and evolution of produced waters associated with gas production in the Palm Valley gas field, Northern Territory, has important implications for issues such as gas reserve calculations, reservoir management and saline water disposal. The occurrence of saline formation water in the Palm Valley field has been the subject of considerable debate. There were no occurrences of mobile water early in the development of the field and only after gas production had reduced the reservoir pressure, was saline formation water produced. Initially this was in small quantities but has increased dramatically with time, particularly after the initiation of compression in November 1996. The produced waters range from highly saline (up to 300,000 mg/L TDS), with unusual enrichments in Ca, Ba and Sr, to low salinity fluids that may represent condensate waters. The Sr isotopic compositions of the waters ( 87 Sr/ 86 Sr = 0.7041-0.7172) are also variable but do not correlate closely with major and trace element abundances. Although the extreme salinity suggests possible involvement of evaporite deposits lower in the stratigraphic sequence, the Sr isotopic composition of the high salinity waters suggests a more complex evolutionary history. The formation waters are chemically and isotopically heterogeneous and are not well mixed. The high salinity brines have Sr isotopic compositions and other geochemical characteristics more consistent with long-term residence within the reservoir rocks than with present-day derivation from a more distal pool of brines associated with evaporites. If the high salinity brines entered the reservoir during the Devonian uplift and were displaced by the reservoir gas into a stagnant pool, which has remained near the reservoir for the last 300-400 Ma, then the size of the brine pool is limited. At a minimum, it might be equivalent to the volume displaced by the reservoired gas

Upper extremity transplantation: current concepts and challenges in an emerging field.

Science.gov (United States)

Elliott, River M; Tintle, Scott M; Levin, L Scott

2014-03-01

Loss of an isolated upper limb is an emotionally and physically devastating event that results in significant impairment. Patients who lose both upper extremities experience profound disability that affects nearly every aspect of their lives. While prosthetics and surgery can eventually provide the single limb amputee with a suitable assisting hand, limited utility, minimal haptic feedback, weight, and discomfort are persistent problems with these techniques that contribute to high rates of prosthetic rejection. Moreover, despite ongoing advances in prosthetic technology, bilateral amputees continue to experience high levels of dependency, disability, and distress. Hand and upper extremity transplantation holds several advantages over prosthetic rehabilitation. The missing limb is replaced with one of similar skin color and size. Sensibility, voluntary motor control, and proprioception are restored to a greater degree, and afford better dexterity and function than prosthetics. The main shortcomings of transplantation include the hazards of immunosuppression, the complications of rejection and its treatment, and high cost. Hand and upper limb transplantation represents the most commonly performed surgery in the growing field of Vascularized Composite Allotransplantation (VCA). As upper limb transplantation and VCA have become more widespread, several important challenges and controversies have emerged. These include: refining indications for transplantation, optimizing immunosuppression, establishing reliable criteria for monitoring, diagnosing, and treating rejection, and standardizing outcome measures. This article will summarize the historical background of hand transplantation and review the current literature and concepts surrounding it.

Geomorphic effects, flood power, and channel competence of a catastrophic flood in confined and unconfined reaches of the upper Lockyer valley, southeast Queensland, Australia

Science.gov (United States)

Thompson, Chris; Croke, Jacky

2013-09-01

Flooding is a persistent natural hazard, and even modest changes in future climate are believed to lead to large increases in flood magnitude. Previous studies of extreme floods have reported a range of geomorphic responses from negligible change to catastrophic channel change. This paper provides an assessment of the geomorphic effects of a rare, high magnitude event that occurred in the Lockyer valley, southeast Queensland in January 2011. The average return interval of the resulting flood was ~ 2000 years in the upper catchment and decreased to ~ 30 years downstream. A multitemporal LiDAR-derived DEM of Difference (DoD) is used to quantify morphological change in two study reaches with contrasting valley settings (confined and unconfined). Differences in geomorphic response between reaches are examined in the context of changes in flood power, channel competence and degree of valley confinement using a combination of one-dimensional (1-D) and two-dimensional (2-D) hydraulic modelling. Flood power peaked at 9800 W m- 2 along the confined reach and was 2-3 times lower along the unconfined reach. Results from the DoD confirm that the confined reach was net erosional, exporting ~ 287,000 m3 of sediment whilst the unconfined reach was net depositional gaining ~ 209,000 m3 of sediment, 70% of the amount exported from the upstream, confined reach. The major sources of eroded sediment in the confined reach were within channel benches and macrochannel banks resulting in a significant increase of channel width. In the unconfined reach, the benches and floodplains were the major loci for deposition, whilst the inner channel exhibited minor width increases. The presence of high stream power values, and resultant high erosion rates, within the confined reach is a function of the higher energy gradient of the steeper channel that is associated with knickpoint development. Dramatic differences in geomorphic responses were observed between the two adjacent reaches of

Competition between the inter-valley scattering and the intra-valley scattering on magnetoconductivity induced by screened Coulomb disorder in Weyl semimetals

Directory of Open Access Journals (Sweden)

Xuan-Ting Ji

2017-10-01

Full Text Available Recent experiments on Weyl semimetals reveal that charged impurities may play an important role. We use a screened Coulomb disorder to model the charged impurities, and study the magneto-transport in a two-node Weyl semimetal. It is found that when the external magnetic field is applied parallel to the electric field, the calculated longitudinal magnetoconductivity shows positive in the magnetic field, which is just the negative longitudinal magnetoresistivity (LMR observed in experiments. When the two fields are perpendicular to each other, the transverse magnetoconductivities are measured. It is found that the longitudinal (transverse magnetoconductivity is suppressed (enhanced sensitively with increasing the screening length. This feature makes it hardly to observe the negative LMR in Weyl semimetals experimentally owing to a small screening length. Our findings gain insight into further understanding on recently actively debated magneto-transport behaviors in Weyl semimetals. Furthermore we studied the relative weight of the inter-valley scattering and the intra-valley scattering. It shows that the former is as important as the latter and even dominates in the case of strong magnetic fields and small screening length. We emphasize that the discussions on inter-valley scattering is out of the realm of one-node model which has been studied.

Gaining, losing, and dry stream reaches at Bear Creek Valley, Oak Ridge, Tennessee, March and September 1994

International Nuclear Information System (INIS)

Robinson, J.A.; Mitchell, R.L. III.

1996-01-01

A study was conducted, to delineate stream reaches that were gaining flow, losing flow, or that were dry in the upper reaches of Bear Creek Valley near the Y-12 Plant in Oak Ridge, Tennessee. The study included a review of maps and discharge data from a seepage investigation conducted at Bear Creek Valley; preparation of tables showing site identification and discharge and stream reaches that were gaining flow, losing flow, or that were dry; and preparation of maps showing measurement site locations and discharge measurements, and gaining, losing, and dry stream reaches. This report will aid in developing a better understanding of ground-water and surface-water interactions in the upper reaches of Bear Creek

Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6. Salt Valley

International Nuclear Information System (INIS)

1984-12-01

Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox Formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the Area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker Trail Formation. The current data base is insufficient to estimate ground-water flow rates and directions in this unit. The middle unit includes the evaporites in the Paradox Formation and no laterally extensive flow systems are apparent. The lower unit consists of the rocks below the Paradox Formation where permeabilities vary widely, and the apparent flow direction is toward the west. 108 refs., 39 figs., 9 tabs

The Health Valley: Global Entrepreneurial Dynamics.

Science.gov (United States)

Dubuis, Benoit

2014-12-01

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

Coupled simulation of meteorological parameters and sound intensity in a narrow valley

Energy Technology Data Exchange (ETDEWEB)

Heimann, D. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Gross, G. [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

1997-07-01

A meteorological mesoscale model is used to simulate the inhomogeneous distribution of temperature and the appertaining development of thermal wind systems in a narrow two-dimensional valley during the course of a cloud-free day. A simple sound particle model takes up the simulated meteorological fields and calculates the propagation of noise which originates from a line source at one of the slopes of this valley. The coupled modeling system ensures consistency of topography, meteorological parameters and the sound field. The temporal behaviour of the sound intensity level across the valley is examined. It is only governed by the time-dependent meteorology. The results show remarkable variations of the sound intensity during the course of a day depending on the location in the valley. (orig.) 23 refs.

Valley- and spin-filter in monolayer MoS2

Science.gov (United States)

Majidi, Leyla; Zare, Moslem; Asgari, Reza

2014-12-01

We propose a valley- and spin-filter based on a normal/ferromagnetic/normal molybdenum disulfide (MoS2) junction where the polarizations of the valley and the spin can be inverted by reversing the direction of the exchange field in the ferromagnetic region. By using a modified Dirac Hamiltonian and the scattering formalism, we find that the polarizations can be tuned by applying a gate voltage and changing the exchange field in the structure. We further demonstrate that the presence of a topological term (β) in the Hamiltonian results in an enhancement or a reduction of the charge conductance depending on the value of the exchange field.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-03-20

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

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

Science.gov (United States)

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

2011-01-01

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

Vegetation - San Felipe Valley [ds172

Data.gov (United States)

California Natural Resource Agency — This Vegetation Map of the San Felipe Valley Wildlife Area in San Diego County, California is based on vegetation samples collected in the field in 2002 and 2005 and...

Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators.

Science.gov (United States)

Ni, Xiang; Purtseladze, David; Smirnova, Daria A; Slobozhanyuk, Alexey; Alù, Andrea; Khanikaev, Alexander B

2018-05-01

Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage ( 1 - 3 ). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light ( 4 - 6 ). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom.

Fully Valley/spin polarized current and Fano factor through the Graphene/ferromagnetic silicene/Graphene junction

Energy Technology Data Exchange (ETDEWEB)

Rashidian, Zeinab; Rezaeipour, Saeid [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Hajati, Yaser [Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Lorestaniweiss, Zeinab, E-mail: rashidian1983z@gmail.com [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Ueda, Akiko [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba (Japan)

2017-02-15

In this work, we study the transport properties of Dirac fermions through the ferromagnetic silicene which is sandwiched between the Graphene leads (G/FS/G). Spin/valley conductance, spin/valley polarization, and also Fano factor are theoretically calculated using the Landauer-Buttiker formula. We find that the fully valley and spin polarized currents through the G/FS/G junction can be obtained by increasing the electric field strength and the length of ferromagnetic silicene region. Moreover, the valley polarization can be tuned from negative to positive values by changing the electric field. We find that the Fano factor also changes with the spin and valley polarization. Our findings of high controllability of the spin and valley transport in such a G/FS/G junction the potential of this junction for spin-valleytronics applications.

Valley photonic crystals for control of spin and topology.

Science.gov (United States)

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

2017-03-01

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

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

Science.gov (United States)

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

2017-07-19

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

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

Science.gov (United States)

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

2008-01-01

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

Upper critical and irreversibility fields in Ni- and Co-doped pnictide bulk superconductors

Science.gov (United States)

Nikolo, Martin; Singleton, John; Solenov, Dmitry; Jiang, Jianyi; Weiss, Jeremy; Hellstrom, Eric

2018-05-01

A comprehensive study of upper critical and irreversibility magnetic fields in Ba(Fe0.95Ni0.05)2As2 (large grain and small grain samples), Ba(Fe0.94Ni0.06)2As2, Ba(Fe0.92Co0.08)2As2, and Ba(Fe0.92Co0.09)2As2 polycrystalline bulk pnictide superconductors was made in pulsed fields of up to 65 T. The full magnetic field-temperature (H-T) phase diagrams, starting at 1.5 K, were measured. The higher temperature, upper critical field Hc2 data are well described by the one-band Werthamer, Helfand, and Hohenberg (WHH) model. At low temperatures, the experimental data depart from the fitted WHH curves, suggesting an emergence of a new phase that could be attributed to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. The large values of the Maki fitting parameter α indicate that the Zeeman pair breaking dominates over the orbital pair breaking and spin-paramagnetic pair-breaking effect is significant in these materials. Possible multi-band structure of these materials is lumped into effective parameters of the single-band model. Table of measured physical parameters allows us to compare these pnictide superconductors for different Co- and Ni- doping levels and granularity.

Highlands of the upper Jequitinhonha valley, Brazil: I - characterization and classification

Directory of Open Access Journals (Sweden)

Fábio Henrique Alves Bispo

2011-08-01

Full Text Available In the upper Jequitinhonha valley, state of Minas Gerais, Brazi, there are large plane areas known as "chapadas", which are separated by areas dissected by tributaries of the Jequitinhonha and Araçuaí rivers. These dissected areas have a surface drainage system with tree, shrub, and grass vegetation, more commonly known as "veredas", i.e., palm swamps. The main purpose of this study was to characterize soil physical, chemical and morphological properties of a representative toposequence in the watershed of the Vereda Lagoa do Leandro, a swamp near Minas Novas, MG, on "chapadas", the highlands of the Alto Jequitinhonha region Different soil types are observed in the landscape: at the top - Typic Haplustox (LVA, in the middle slope - Xanthic Haplustox (LA, at the footslope - Xanthic Haplustox, gray color, here called "Gray Haplustox" ("LAC" and, at the bottom of the palm swamp - Typic Albaquult (GXbd. These soils were first morphologically described; samples of disturbed and undisturbed soils were collected from all horizons and subhorizons, to evaluate their essential physical and chemical properties, by means of standard determination of Fe, Al, Mn, Ti and Si oxides after sulfuric extraction. The contents of Fe, Al and Mn, extracted with dithionite-citrate-bicarbonate and oxalate treatments, were also determined. In the well-drained soils of the slope positions, the typical morphological, physical and chemical properties of Oxisols were found. The GXbd sample, from the bottom of the palm swamp, is grayish and has high texture gradient (B/A and massive structure. The reduction of the proportion of crystalline iron compounds and the low crystallinity along the slope confirmed the loss of iron during pedogenesis, which is reflected in the current soil color. The Si and Al contents were lowest in the "LAC" soil. There was a decrease of the Fe2O3/TiO2 ratio downhill, indicating progressive drainage restriction along the toposequence. The genesis

Relationship between petrographic pore types and core measurements in sandstones of the Monserrate Formation, upper Magdalena Valley, Colombia

International Nuclear Information System (INIS)

Ehrlich, R; Cobaleda, G; Barclay, Ferm

1997-01-01

Patterns of porosity in sandstones of the Monserrate Formation (Upper Magdalena Valley) exposed in polished blocks have been digitally recorded using an image processor coupled to a scanning electron microscope operated in back scatter electron mode. Additionally, porosity, permeability and response to mercury injection-capillary pressure tests were measured on some of the imaged samples. Porosity pattern were evaluated via an erosion/dilation-differencing image-processing algorithm and then classified by the self-training classifier, SAWVEC. Changes in the resulting pore type proportions were strongly associated with changes in the mercury porosimetry curves. From the image processing data, five pore types, sufficient to include all of the variability in size and shape of the patterns of porosity, were identified. Variations in the number of pares of each type per unit cross sectional area were related to variations in permeability. The resultant relationships with mercury porosimetry demonstrated that pares of the same type tends to form microcircuits characterized by a limited throat size range. Permeability modeling showed that intergranular Pare Types 2 and 4 (secondary porosity resulting from carbonate dissolution) are responsible for permeability in the 0,01 - 0,1 0 Darcy range. Type 5 pares (large molds) slightly contribute to permeability, except in coarse grained rocks where they are efficiently connected by micro fractures

SPRINGS WITH CALCAREOUS TUFA IN THE VALLEY OF THE JAMNE CREEK IN GORCE

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Roksana Krause

2015-01-01

Full Text Available The study gives a detail characteristic of a hard water springs habitat with the communities of Cratoneurion commutati (habitat code of Nature 2000: 7220, localized within Nature 2000 protected area Ostoja Gorczańska PLH120018, in an upper part of the valley of Jamne creek. The plants are described along with the main habitat parameters, namely: altitude, exposition, slope gradient, insolation, type of bedrock, water flow regime and the spring outflow efficiency. The temperature, pH, electrical conductivity were measured in the field, the concentrations of Ca and Mg in spring water were measured by Atomic Absorption Spectroscopy (AAS. The investigated headwater areas are small (0.7–80 m2 and highly differentiated by the intensity of calcareous tufa precipitation and the degree of plant cover development.

Four newly recorded species of Dryopteridaceae from Kashmir valley, India

Directory of Open Access Journals (Sweden)

SHAKOOR AHMAD MIR

2014-04-01

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

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

International Nuclear Information System (INIS)

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

2000-01-01

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

Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene.

Science.gov (United States)

Hunt, B M; Li, J I A; Zibrov, A A; Wang, L; Taniguchi, T; Watanabe, K; Hone, J; Dean, C R; Zaletel, M; Ashoori, R C; Young, A F

2017-10-16

The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers.The phase diagram of bilayer graphene at high magnetic fields has been an outstanding question, with orders possibly between multiple internal quantum degrees of freedom. Here, Hunt et al. report the measurement of the valley and orbital order, allowing them to directly reconstruct the phase diagram.

Root-collar diameter and third-year survival of three bottomland hardwoods planted on former agricultural fields in the Lower Mississippi Alluvial Valley

Science.gov (United States)

Emile S. Gardiner; Douglass F. Jacobs; Ronald P. Overton; George Hernandez

2009-01-01

Athough the Lower Mississippi Alluvial Valley (LMAV) has experienced substantial afforestation of former agricultural fields during the past 2 decades, seedling standards that support satisfactory outplanting performance of bottomland hardwood tree species are not available. A series of experimental plantations, established on three afforestation sites in the LMAV,...

Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators

Science.gov (United States)

Slobozhanyuk, Alexey

2018-01-01

Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage (1–3). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light (4–6). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom. PMID:29756032

Lead and other heavy metals in stream sediments in the area of Meža valley

Directory of Open Access Journals (Sweden)

Julija Fux

2007-12-01

Full Text Available In the Meža valley, lead – zinc ore has been exploited and processed for more than 300 years, which has strongly influenced the environment.Previous investigation shave shown increased concentrations of lead and some other metals. At the end of the 20th century, the Meža River was considered a stream with the highest concentrations of heavy metals in Slovenia.When the mine and processing plants ceased to operate, the direct transfer of heavy metals into the environment has strongly decreased. However, the deposits of poor ore and wastes from ore processing have remained as an indirect source of heavy metal pollution. From those places heavy metals have been washed out into the nearby streams, and carried into the Meža River and further into the Drava River. Chemical analysis of the Meža River and its tributaries has shown heavy pollution of the upper Meža River sediments with lead, zinc, molybdenum and cadmium, and partly with arsenic. In the lower Meža valley, those concentrations are mildly decreased. Concentrations of cobalt, chrome, copper and nickel are increased in the area around Ravne as a result of the ironworks industry. Mušenik and Jančarjev potok, both tributaries of the Meža River, contribute a high portion of heavy metal load to the Meža River. A specific case is Helenski potok,in which the concentrations of heavy metals strongly surpass the concentrations measured at all other locations. Although more than 10 years have passed since the mine and ore processing plant in the upper Meža valley were closed, the production has ceased and the rehabilitation measures have been taken, the environment in the upper Meža valley is still highly polluted.

Valley-chiral quantum Hall state in graphene superlattice structure

Science.gov (United States)

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

2016-05-01

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

Sediment storage and transport in Pancho Rico Valley during and after the Pleistocene-Holocene transition, Coast Ranges of central California (Monterey County)

Science.gov (United States)

Garcia, A.F.; Mahan, S.A.

2009-01-01

Factors influencing sediment transport and storage within the 156??6 km2 drainage basin of Pancho Rico Creek (PRC), and sediment transport from the PRC drainage basin to its c. 11000 km2 mainstem drainage (Salinas River) are investigated. Numeric age estimates are determined by optically stimulated luminescence (OSL) dating on quartz grains from three sediment samples collected from a 'quaternary terrace a (Qta)' PRC terrace/PRC-tributary fan sequence, which consists dominantly of debris flow deposits overlying fluvial sediments. OSL dating results, morphometric analyses of topography, and field results indicate that the stormy climate of the Pleistocene-Holocene transition caused intense debris-flow erosion of PRC- tributary valleys. However, during that time, the PRC channel was backfilled by Qta sediment, which indicates that there was insufficient discharge in PRC to transport the sediment load produced by tributary-valley denudation. Locally, Salinas Valley alluvial stratigraphy lacks any record of hillslope erosion occurring during the Pleistocene-Holocene transition, in that the alluvial fan formed where PRC enters the Salinas Valley lacks lobes correlative to Qta. This indicates that sediment stripped from PRC tributaries was mostly trapped in Pancho Rico Valley despite the relatively moist climate of the Pleistocene-Holocene transition. Incision into Qta did not occur until PRC enlarged its drainage basin by c. 50% through capture of the upper part of San Lorenzo Creek, which occurred some time after the Pleistocene-Holocene transition. During the relatively dry Holocene, PRC incision through Qta and into bedrock, as well as delivery of sediment to the San Ardo Fan, were facilitated by the discharge increase associated with stream-capture. The influence of multiple mechanisms on sediment storage and transport in the Pancho Rico Valley-Salinas Valley system exemplifies the complexity that (in some instances) must be recognized in order to correctly

Light-absorbing Aerosol Properties in the Kathmandu Valley during SusKat-ABC Field Campaign

Science.gov (United States)

Kim, S.; Yoon, S.; Kim, J.; Cho, C.; Jung, J.

2013-12-01

Light-absorbing aerosols, such as black carbon (BC), are major contributors to the atmospheric heating and the reduction of solar radiation reaching at the earth's surface. In this study, we investigate light-absorption and scattering properties of aerosols (i.e., BC mass concentration, aerosol solar-absorption/scattering efficiency) in the Kathmandu valley during Sustainable atmosphere for the Kathmandu valley (SusKat)-ABC campaign, from December 2012 to February 2013. Kathmandu City is among the most polluted cities in the world. However, there are only few past studies that provide basic understanding of air pollution in the Kathmandu Valley, which is not sufficient for designing effective mitigation measures (e.g., technological, financial, regulatory, legal and political measures, planning strategies). A distinct diurnal variation of BC mass concentration with two high peaks observed during wintertime dry monsoon period. BC mass concentration was found to be maximum around 09:00 and 20:00 local standard time (LST). Increased cars and cooking activities including substantial burning of wood and other biomass in the morning and in the evening contributed to high BC concentration. Low BC concentrations during the daytime can be explain by reduced vehicular movement and cooking activities. Also, the developmements of the boundary layer height and mountain-valley winds in the Kathmandu Valley paly a crucial role in the temproal variation of BC mass concentrations. Detailed radiative effects of light-absorbing aerosols will be presented.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

Science.gov (United States)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have

Bear Creek Valley Floodplain hot spot removal early action characterization field data summary report, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1998-04-01

This report summarizes the field and laboratory efforts as a result of the Bear Creek Floodplain Hot Spot Removal Project Early Action. The purpose of this project was to collect data necessary to assess contaminant levels in the Bear Creek Valley Floodplain and evaluate the risk posed by the sites. This report provides information on the background of the site, characterization of site and field activities, results of field and laboratory data collected, extent and distribution of contamination, and an assessment of the future risk posed by the site

Seismic imaging of the metamorphism of young sediment into new crystalline crust in the actively rifting Imperial Valley, California

Science.gov (United States)

Han, Liang; Hole, John; Stock, Joann; Fuis, Gary S.; Williams, Colin F.; Delph, Jonathan; Davenport, Kathy; Livers, Amanda

2016-01-01

Plate-boundary rifting between transform faults is opening the Imperial Valley of southern California and the rift is rapidly filling with sediment from the Colorado River. Three 65–90 km long seismic refraction profiles across and along the valley, acquired as part of the 2011 Salton Seismic Imaging Project, were analyzed to constrain upper crustal structure and the transition from sediment to underlying crystalline rock. Both first arrival travel-time tomography and frequency-domain full-waveform inversion were applied to provide P-wave velocity models down to ∼7 km depth. The valley margins are fault-bounded, beyond which thinner sediment has been deposited on preexisting crystalline rocks. Within the central basin, seismic velocity increases continuously from ∼1.8 km/s sediment at the surface to >6 km/s crystalline rock with no sharp discontinuity. Borehole data show young sediment is progressively metamorphosed into crystalline rock. The seismic velocity gradient with depth decreases approximately at the 4 km/s contour, which coincides with changes in the porosity and density gradient in borehole core samples. This change occurs at ∼3 km depth in most of the valley, but at only ∼1.5 km depth in the Salton Sea geothermal field. We interpret progressive metamorphism caused by high heat flow to be creating new crystalline crust throughout the valley at a rate comparable to the ≥2 km/Myr sedimentation rate. The newly formed crystalline crust extends to at least 7–8 km depth, and it is shallower and faster where heat flow is higher. Most of the active seismicity occurs within this new crust.

Seismic imaging of the metamorphism of young sediment into new crystalline crust in the actively rifting Imperial Valley, California

Science.gov (United States)

Han, Liang; Hole, John A.; Stock, Joann M.; Fuis, Gary S.; Williams, Colin F.; Delph, Jonathan R.; Davenport, Kathy K.; Livers, Amanda J.

2016-11-01

Plate-boundary rifting between transform faults is opening the Imperial Valley of southern California and the rift is rapidly filling with sediment from the Colorado River. Three 65-90 km long seismic refraction profiles across and along the valley, acquired as part of the 2011 Salton Seismic Imaging Project, were analyzed to constrain upper crustal structure and the transition from sediment to underlying crystalline rock. Both first arrival travel-time tomography and frequency-domain full-waveform inversion were applied to provide P-wave velocity models down to ˜7 km depth. The valley margins are fault-bounded, beyond which thinner sediment has been deposited on preexisting crystalline rocks. Within the central basin, seismic velocity increases continuously from ˜1.8 km/s sediment at the surface to >6 km/s crystalline rock with no sharp discontinuity. Borehole data show young sediment is progressively metamorphosed into crystalline rock. The seismic velocity gradient with depth decreases approximately at the 4 km/s contour, which coincides with changes in the porosity and density gradient in borehole core samples. This change occurs at ˜3 km depth in most of the valley, but at only ˜1.5 km depth in the Salton Sea geothermal field. We interpret progressive metamorphism caused by high heat flow to be creating new crystalline crust throughout the valley at a rate comparable to the ≥2 km/Myr sedimentation rate. The newly formed crystalline crust extends to at least 7-8 km depth, and it is shallower and faster where heat flow is higher. Most of the active seismicity occurs within this new crust.

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

KAUST Repository

Li, Hang; Wang, Xuhui; Manchon, Aurelien

2016-01-01

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

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

KAUST Repository

Li, Hang

2016-01-11

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

Hydrogeology of the Owego-Apalachin Elementary School Geothermal Fields, Tioga County, New York

Science.gov (United States)

Williams, John H.; Kappel, William M.

2015-12-22

The hydrogeology of the Owego-Apalachin Elementary School geothermal fields, which penetrate saline water and methane in fractured upper Devonian age bedrock in the Owego Creek valley, south-central New York, was characterized through the analysis of drilling and geophysical logs, water-level monitoring data, and specific-depth water samples. Hydrogeologic insights gained during the study proved beneficial for the design of the geothermal drilling program and protection of the overlying aquifer during construction, and may be useful for the development of future geothermal fields and other energy-related activities, such as drilling for oil and natural gas in similar fractured-bedrock settings.

Theoretical upper critical field Hc2 for inhomogeneous high temperature superconductors

International Nuclear Information System (INIS)

Caixeiro, E.S.; Gonzalez, J.L.; Mello, E.V.L. de

2004-01-01

We present the theoretical upper critical field H c2 (T) of the high temperature superconductors (HTSC), calculated through a linearized Ginzburg-Landau equation modified to consider the intrinsic inhomogeneity of the HTSC. The unusual behavior of H c2 (T) for these compounds, and other properties like the Meissner and Nernst effects detected at temperatures much higher than the critical temperature T c of the sample, are explained by the approach

Current hot spot in the spin-valley blockade in carbon nanotubes

Science.gov (United States)

Széchenyi, Gábor; Pályi, András

2013-12-01

We present a theoretical study of the spin-valley blockade transport effect in a double quantum dot defined in a straight carbon nanotube. We find that intervalley scattering due to short-range impurities completely lifts the spin-valley blockade and induces a large leakage current in a certain confined range of the external magnetic field vector. This current hot spot emerges due to different effective magnetic fields acting on the spin-valley qubit states of the two quantum dots. Our predictions are compared to a recent measurement [F. Pei , Nat. Nanotech.1748-338710.1038/nnano.2012.160 7, 630 (2012)]. We discuss the implications for blockade-based schemes for qubit initialization/readout and motion sensing of nanotube-based mechanical resonators.

Determination of Vertical Velocity Field of Southernmost Longitudinal Valley in Eastern Taiwan: A Joint Analysis of Leveling and GPS Measurements

Directory of Open Access Journals (Sweden)

Horng-Yue Chen

2012-01-01

Full Text Available In order to provide a detailed vertical velocity field in southernmost Longitudinal Valley where shows a complex three-fault system at the plate suture between Philippine Sea plate and Eurasia, we conducted leveling and GPS measurements, compiled data from previous surveys and combined them into a single data set. We compiled precise leveling results from 1984 to 2009, include 5 E-W trending and one N-S trending routes. We calculated the GPS vertical component from 10 continuous stations and from 89 campaign-mode stations from 1995 to 2010. The interseismic vertical rates are estimated by removing the co- and post-seismic effects of major large regional and nearby earthquakes. A stable continuous station S104 in the study area was adopted as the common reference station. We finally establish a map of the interseismic vertical velocity field. The interseismic vertical deformation was mainly accommodated by creeping/thrusting along two east-dipping strands of the three-fault system: the Luyeh and Lichi faults. The most dominant uplift of 30 mm yr-1 occurs at the hanging wall of the Lichi fault on the western Coastal Range. However the rate diminishes away from the fault in the hanging wall. The Quaternary tablelands inside of the Longitudinal Valley reveals uplift with a rate of 5 - 10 mm yr-1. Outside of the tablelands, the rest of the Longitudinal Valley flat area indicates substantial subsidence of -10 to -20 mm yr-1. Finally, it appears that the west-dipping blind fault under the eastern side of the Central Range does not play a significant role on interseismic deformation with subsidence rate of -5 to -10 mm yr-1.

Geo morphological setting and main technological features of new Middle and Upper Pleistocene sites in the Lower Manzanares River Valley (Madrid, Spain); Contexto geomorfologico y principales rasgos tecnologicos de nuevos yacimientos del Pleistoceno Medio y Superior en el Valle Inferior del Manzanares (Madrid, Espana)

Energy Technology Data Exchange (ETDEWEB)

Silva, P. G.; Lopez Recio, M.; Cuartero, F.; Baena, J.; Tapias, F.; Manzano, I.; Martin, D.; Morin, J.; Roquero, E.

2012-11-01

The archaeological works developed during the years 1996 in the site of Tafesa, 2005 in the 12 de Octubre Metro Station site and 2006 in the confluence of the Butarque Stream (Villaverde-Barrio de Butarque site) located south of the Madrid City (Spain), have provided new lithic assemblages. These assemblages have been stratigraphic ally contextualized in the Pleistocene deposits of the Lower Manzanares river valley within the so-called Manzanares Complex Terrace (TCMZ). This fluvial terrace constitutes an anomalous thickened (20-15m) deposit at {+-}22-16m above the present river thalweg mainly developed along the right (southern) valley margin. This fluvial level has been traditionally considered of middle Pleistocene age on the basis of the acheulian lithics and faunal assemblages typically located within its lower stratigraphic layers. Certainly, the Tafesa is a fluvial terrace site at {+-}22 m with acheulian industry and middle Pleistocene faunal remains at its lower sedimentary sequence. However, the upper sedimentary levels of this same terrace in the 12 de Octubre y Villaverde-Butarque sites throw lithic assemblages of the lower and upper Paleolithic belonging to upper Pleistocene, as suggested by the available set of TL and OSL dates for the zone. The analyses developed in this study indicate that the development of this thickened fluvial terrace started during the end of the middle Pleistocene, but also comprise the whole Oxygen Isotopic Stage OIS 5 during the upper Pleistocene. (Author) 95 refs.

Geochemistry of waters in the Valley of Ten Thousand Smokes region, Alaska

Science.gov (United States)

Keith, T.E.C.; Thompson, J.M.; Hutchinson, R.A.; White, L.D.

1992-01-01

Meteoric waters from cold springs and streams outside of the 1912 eruptive deposits filling the Valley of Ten Thousand Smokes (VTTS) and in the upper parts of the two major rivers draining the 1912 deposits have similar chemical trends. Thermal springs issue in the mid-valley area along a 300-m lateral section of ash-flow tuff, and range in temperature from 21 to 29.8??C in early summer and from 15 to 17??C in mid-summer. Concentrations of major and minor chemical constituents in the thermal waters are nearly identical regardless of temperature. Waters in the downvalley parts of the rivers draining the 1912 deposits are mainly mixtures of cold meteoric waters and thermal waters of which the mid-valley thermal spring waters are representative. The weathering reactions of cold waters with the 1912 deposits appear to have stabilized and add only subordinate amounts of chemical constituents to the rivers relative to those contributed by the thermal waters. Isotopic data indicate that the mid-valley thermal spring waters are meteoric, but data is inconclusive regarding the heat source. The thermal waters could be either from a shallow part of a hydrothermal system beneath the 1912 vent region or from an incompletely cooled, welded tuff lens deep in the 1912 ash-flow sheet of the upper River Lethe area. Bicarbonate-sulfate waters resulting from interaction of near-surface waters and the cooling 1953-1968 southwest Trident plug issue from thermal springs south of Katmai Pass and near Mageik Creek, although the Mageik Creek spring waters are from a well-established, more deeply circulating hydrothermal system. Katmai caldera lake waters are a result of acid gases from vigorous drowned fumaroles dissolving in lake waters composed of snowmelt and precipitation. ?? 1992.

Variogram based and Multiple - Point Statistical simulation of shallow aquifer structures in the Upper Salzach valley, Austria

Science.gov (United States)

Jandrisevits, Carmen; Marschallinger, Robert

2014-05-01

Quarternary sediments in overdeepened alpine valleys and basins in the Eastern Alps bear substantial groundwater resources. The associated aquifer systems are generally geometrically complex with highly variable hydraulic properties. 3D geological models provide predictions of both geometry and properties of the subsurface required for subsequent modelling of groundwater flow and transport. In hydrology, geostatistical Kriging and Kriging based conditional simulations are widely used to predict the spatial distribution of hydrofacies. In the course of investigating the shallow aquifer structures in the Zell basin in the Upper Salzach valley (Salzburg, Austria), a benchmark of available geostatistical modelling and simulation methods was performed: traditional variogram based geostatistical methods, i.e. Indicator Kriging, Sequential Indicator Simulation and Sequential Indicator Co - Simulation were used as well as Multiple Point Statistics. The ~ 6 km2 investigation area is sampled by 56 drillings with depths of 5 to 50 m; in addition, there are 2 geophysical sections with lengths of 2 km and depths of 50 m. Due to clustered drilling sites, indicator Kriging models failed to consistently model the spatial variability of hydrofacies. Using classical variogram based geostatistical simulation (SIS), equally probable realizations were generated with differences among the realizations providing an uncertainty measure. The yielded models are unstructured from a geological point - they do not portray the shapes and lateral extensions of associated sedimentary units. Since variograms consider only two - point spatial correlations, they are unable to capture the spatial variability of complex geological structures. The Multiple Point Statistics approach overcomes these limitations of two point statistics as it uses a Training image instead of variograms. The 3D Training Image can be seen as a reference facies model where geological knowledge about depositional

Anatomy of a mountain: The Thebes Limestone Formation (Lower Eocene) at Gebel Gurnah, Luxor, Nile Valley, Upper Egypt

Science.gov (United States)

King, Christopher; Dupuis, Christian; Aubry, Marie-Pierre; Berggren, William A.; Knox, Robert O.'B.; Galal, Wael Fathi; Baele, Jean-Marc

2017-12-01

We present a detailed geologic study of the Thebes Formation at Gebel Gurnah in its locus typicus on the West Bank (opposite Luxor) of the Nile River in the Upper Nile Valley, Egypt. This is the first detailed measurement and lithologic description of the ∼340 m thick (predominantly) carbonate section. The Thebes Formation is divided into thirteen major lithic units (A to M). We interpret data on the lithologic succession and variations, whole rock/clay mineralogy, and macro/micropaleontology in terms of deposition on a shallow carbonate platform episodically influenced by continental runoff, and describe six depositional sequences that we place in the global framework of Lower Eocene (Ypresian) sequence stratigraphy. We note however significant incompatibilities between the Thebes depositional sequences and the global sequences. We emend the definition of the Thebes Formation by defining its top as corresponding to level 326 m at the top of Nodular Limestone 'L' (NLL), and assigning the overlying beds to the Minia Limestone Formation. New biostratigraphic data and revision of previous studies establish the direct assignment of the Thebes Formation to planktonic foraminiferal Zones E4/P6b (upper part), E5/P7 and (indirectly) Zone E6/P8, and (probably, indirectly) Zone E7a/;P9;, and to calcareous nannofossil Zone NP12 and lower Zone NP13 of the Lower Eocene (Ypresian) and provide a temporal framework spanning ∼ 2.8 Myr from towards the end of the Early Eocene. Dominantly carbonate deposition, with a strongly reduced detrital influx, occurred on a very wide shelf (probably) at least ∼ 100 km from the coastline. The thick sedimentary succession and the marked vertical lithologic variations are interpreted as resulting from sea level fluctuations imprinted on a long-term decrease in sea-level associated with rapid subsidence reflecting tectonic relaxation after the major Late Paleocene tectonic reorganization of the Syrian Arc.

Influence of grain size and upper critical magnetic field on global pinning force of bronze-processed Nb/sub 3/Sn compound

International Nuclear Information System (INIS)

Ochiai, S.; Osamura, K.

1986-01-01

In order to know the dependency of global pinning force of Nb/sub 3/Sn compound on grain size and upper critical magnetic field, the global pinning force was measured at 3-15 T using bronze-processed multifilamentary composites. The grain size and upper critical magnetic field were varied by two types of annealing treatment: one is the isothermal annealing at 873, 973 and 1073 K up to 1730 ks and another is the two-stage annealing (low temperature annealing to form fine grains at 873 K for 1730 ks + high temperature annealing to raise upper critical magnetic field at 1073 K up to 18 ks). In the case of isothermal annealing treatment, both of grain size and upper critical magnetic field increased with increasing annealing temperature and time except for the annealing treatments at high temperature for prolonged times. In the case of two-stage annealing, both of them increased with second stage annealing time. The increase in grain size led to decrease in the pinning force but the increase in upper critical magnetic field to increase in it. From the analysis of the present data based on the Suenaga's speculation concerning with the density of pinning site and the Kramer's equation, it was suggested that the pinning force is, to a first approximation, proportional to the product of inverse grain size and (1-h)/sup 2/h/sup 1/2/ where h is the reduced magnetic field

Solar magnetism eXplorer (SolmeX). Exploring the magnetic field in the upper atmosphere of our closest star

Science.gov (United States)

Peter, Hardi; Abbo, L.; Andretta, V.; Auchère, F.; Bemporad, A.; Berrilli, F.; Bommier, V.; Braukhane, A.; Casini, R.; Curdt, W.; Davila, J.; Dittus, H.; Fineschi, S.; Fludra, A.; Gandorfer, A.; Griffin, D.; Inhester, B.; Lagg, A.; Landi Degl'Innocenti, E.; Maiwald, V.; Sainz, R. Manso; Martínez Pillet, V; Matthews, S.; Moses, D.; Parenti, S.; Pietarila, A.; Quantius, D.; Raouafi, N.-E.; Raymond, J.; Rochus, P.; Romberg, O.; Schlotterer, M.; Schühle, U.; Solanki, S.; Spadaro, D.; Teriaca, L.; Tomczyk, S.; Trujillo Bueno, J.; Vial, J.-C.

2012-04-01

The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the underlying physical processes that drive the violent dynamics of the solar corona—that can also affect life on Earth. SolmeX, a fully equipped solar space observatory for remote-sensing observations, will provide the first comprehensive measurements of the strength and direction of the magnetic field in the upper solar atmosphere. The mission consists of two spacecraft, one carrying the instruments, and another one in formation flight at a distance of about 200 m carrying the occulter to provide an artificial total solar eclipse. This will ensure high-quality coronagraphic observations above the solar limb. SolmeX integrates two spectro-polarimetric coronagraphs for off-limb observations, one in the EUV and one in the IR, and three instruments for observations on the disk. The latter comprises one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric studies. SOHO and other existing missions have investigated the emission of the upper atmosphere in detail (not considering polarization), and as this will be the case also for missions planned for the near future. Therefore it is timely that SolmeX provides the final piece of the observational quest by measuring the magnetic field in the upper atmosphere through polarimetric observations.

Electronic properties in a two-dimensional disordered electron liquid: Spin-valley interplay

International Nuclear Information System (INIS)

Burmistrov, I. S.; Chtchelkatchev, N. M.

2008-01-01

We report a detailed study of the influence of the spin and valley splittings on such physical observables of the two-dimensional disordered electron liquid as resistivity and spin and valley susceptibilities. We explain qualitatively the nonmonotonic dependence of the resistivity on temperature in the presence of a parallel magnetic field. In the presence of either spin or valley splitting we predict a temperature dependence of the resistivity with two maximum points

Distribution of air pollutants in the Inn Valley atmosphere during high concentration events in winter 2006

International Nuclear Information System (INIS)

Schnitzhofer, R.; Norman, M; Dunkl, J.; Wistaler, A.; Hansel, A.; Neininger, B.; Gohm, A.

2006-01-01

Full text: The goal of the INNOX field campaign, which took place during January and February 2006 near the town of Schwaz, was to obtain a three-dimensional picture of the spatial distribution of air pollutants in the Inn Valley during wintertime. For this purpose continuous ground based measurements and, on six chosen days, vertical profiles within the lowest 200 m above ground level (AGL) of the valley atmosphere of certain VOCs (benzene, toluene, etc.) and CO were performed using a proton-transfer-reaction mass spectrometry instrument (PTR-MS). For the soundings a 200-m long teflon line was fixed on a tethered balloon through which the air was sucked to the PTR-MS instrument and to a CO analyser. Next to the inlet on the tethered balloon meteorological data, such as air temperature, pressure, wind, were measured as well. Above the lowest 200 m AGL a research aircraft from MetAir AG (Switzerland), equipped with various instruments for in-situ measurements of air pollutants and meteorological data, was operated. A typical flight pattern consisted of five vertical cross sections between about 150 to 2500 m AGL and lasted about three hours. Altogether 25 hours of aircraft measurements were carried out on six different days. The combination of low-level balloon measurements and upper-level aircraft observations yields vertical profiles of various parameters which cover the whole valley atmosphere. Preliminary results which show strong vertical but also horizontal gradients of air pollutant concentrations will be presented. (author)

Characteristic of selected frequency luminescence for paleo-debris flow deposits in Jiangjia valley

International Nuclear Information System (INIS)

Liu Zhaowen; Wei Mingjian; Pan Baolin; Liu Chao; Li Dongxu

2008-01-01

Eight paleo-debris flow samples from Nideping, Duozhao, Dawazi valley, and Jiangjia valley in Yunnan Province were tested with BG2003 luminescence spectrograph. The characteristic spectra of the selected frequency luminescence of paleo-debris flow deposits from the different locations were obtained. Excited at 488 nm, the wavelengths of emission photons from all samples are 300, 310, 320, 400 and 460 nm. With green excitation (532 nm), the wavelengths of emission photons from all samples are 300, 310, 320 and 460 nm. Then it is determined that the luminescence spectrographs of Nideping are almost same in different time, however, they are different in Dawazi valley and Duozhao. Taking Nideping for example, excited at green, the debris flow substances from the upper, middle, or lower zone of this platform. Response to increasing irradiation dose at 310, 320, and 460 nm, we can define the wavelengths used for dating. (authors)

Valley photonic crystals for control of spin and topology

Energy Technology Data Exchange (ETDEWEB)

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

2016-11-28

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

Large Spin-Valley Polarization in Monolayer MoTe2 on Top of EuO(111)

KAUST Repository

Zhang, Qingyun

2015-12-08

The electronic properties of monolayer MoTe2 on top of EuO(111) are studied by first-principles calculations. Strong spin polarization is induced in MoTe2, which results in a large valley polarization. In a longitudinal electric field this will result in a valley and spin-polarized charge Hall effect. The direction of the Hall current as well as the valley and spin polarizations can be tuned by an external magnetic field. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiocarbon ages of upper quaternary deposit in central Nepal and their geomorphological significance

International Nuclear Information System (INIS)

Yamanaka, Hidetsugu

1982-01-01

The author visited Nepal from October, 1980, to February, 1981, investigated the geomorphology and upper Quaternary geology in Central Nepal, and collected a number of samples for radiocarbon dating. After returning to his university, he dated ten samples by himself. In Nepal, radiocarbon age has been scarcely reported as yet, besides in Kathmandu valley. Therefore, the author's ten data of the age are very important for the late Quaternary chronological study of Nepal Himalayas. In this paper, the author describes sampling localities and horizons, dating results and their geomorphological significance. These ten samples included Pokhara valley, Marsyandi Kohla, Modi Khola, Madi Khola and Muktinath samples. Some conclusion was derived as for the geomorphological development in central Nepal: The last Himalayan glacial age had already ended before 9,000 yr BP (years before A.D. 1950); In the Midland region, from 4,300 to 600 yr BP, some large-scale mudflows broke out nearly contemporaneously in the upper valleys, and they flowed down torrentially and catastrophically to deposit in the middle course of rivers. But the cause of vast quantity of material suddenly brought down from the Great Himalayas has been still left unexplained. The conclusion like this also was able to be applied to the middle Marsyandi Khola and the Pokhara valley. The wide-spread schema that the river was aggraded in the glacial age and degraded in the interglacial age may not be applicable to the rivers in the Midland region of Nepal Himalayas. (Wakatsuki, Y.)

Land degradation trends in upper catchments and morphological developments of braided rivers in drylands: the case of a marginal graben of the Ethiopian Rift Valley

Science.gov (United States)

Demissie, Biadgilgn; Frankl, Amaury; Haile, Mitiku; Nyssen, Jan

2014-05-01

Braided rivers have received relatively little attention in research and development activities in drylands. However, they strongly impact agroecology and agricultural activities and thereby local livelihoods. The Raya Graben (3750 km² including the escarpment) is a marginal graben of the Ethiopian Rift Valley located in North Ethiopia. In order to study the dynamics of braided rivers and the relationship with biophysical controls, 20 representative catchments were selected, ranging between 15 and 311 km². First, the 2005 morphology (length, area) of the braided rivers was related to biophysical controls (vegetation cover, catchment area and slope gradient in the steep upper catchments and gradient in the graben bottom). Second, the changes in length of the braided rivers were related to vegetation cover changes in the upper catchments since 1972. Landsat imagery was used to calculate the Normalized Difference Vegetation Index (NDVI), and to map vegetation cover and the total length of the braided rivers. Spot CNES imagery available from Google Earth was used to identify the total area of the braided rivers in 2005. A linear regression analysis revealed that the length of braided rivers was positively related to the catchment area (R²=0.32, p<0.01), but insignificantly related to vegetation cover in the upper catchments. However, there is an indication that it is an important factor in the relationship calculated for 2005 (R²=0.2, p=0.064). Similarly, the area occupied by the braided rivers was related to NDVI (R²=0.24, p<0.05) and upper catchment area (R²=0.447, p<0.01). Slope gradient is not an important explanatory factor. This is related to the fact that slope gradients are steep (average of 38.1%) in all upper and gentle (average of 3.4%) in graben bottom catchments. The vegetation cover in the upper catchments shows a statistically insignificant increasing trend (R²=0.73, p=0.067) over the last 40 years, whereas length of rivers in the graben bottom

2012 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Upper Naches River, Washington

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data of the Upper Naches River Valley and Nile Slide area of interest on September 30th,...

Temperature dependence of the upper critical field of type II superconductors with fluctuation effects

International Nuclear Information System (INIS)

Mikitik, G.P.

1992-01-01

Fluctuations of the order parameter are taken into consideration in an analysis of the temperature dependence of the upper critical field of a type II superconductor with a three-dimensional superconductivity. This temperature dependence is of universal applicability, to all type II superconductors, if the magnetic fields and temperatures are expressed in appropriate units. This dependence is derived explicitly for the regions of strong and weak magnetic fields. The results are applied to high T c superconductors, for which fluctuation effects are important. For these superconductors, the H c2 (T) dependence is quite different from the linear dependence characteristic of the mean-field theory, over a broad range of magnetic fields

Upper Critical Field and de Haas-van Alphen Oscillations in KOs2O6 Measured in a Hybrid Magnet

Science.gov (United States)

Taichi Terashima,; Nobuyuki Kurita,; Atsushi Harada,; Kota Kodama,; Jun-ichi Yamaura,; Zenji Hiroi,; Hisatomo Harima,; Shinya Uji,

2010-08-01

Magnetic torque measurements have been performed on a KOs2O6 single crystal in magnetic fields up to 35.3 T and at temperatures down to 0.6 K. The upper critical field is determined to be ˜30 T. De Haas-van Alphen oscillations are observed. A large mass enhancement of (1+λ) = m* / mband = 7.6 is found. It is suggested that, for the large upper critical field to be reconciled with Pauli paramagnetic limiting, the observed mass enhancement must be of electron-phonon origin, including electron-rattling-mode interactions, for the most part.

Sedimentary record and luminescence chronology of palaeoflood events along the Gold Gorge of the upper Hanjiang River, middle Yangtze River basin, China

Science.gov (United States)

Guo, Yongqiang; Huang, Chun Chang; Zhou, Yali; Pang, Jiangli; Zha, Xiaochun; Fan, Longjiang; Mao, Peini

2018-05-01

Palaeoflood slackwater deposits (SWDs) along the river banks have important implications for the reconstruction of the past hydro-climatic events. Two palaeoflood SWD beds were identified in the Holocene loess-soil sequences on the cliff river banks along the Gold Gorge of the upper Hanjiang River by field investigation and laboratory analysis. They have recorded two palaeoflood events which were dated by optically stimulated luminescence to 3.2-2.8 ka and 2.1-1.8 ka, respectively. The reliability of the ages obtained for the two events are further confirmed by the presence of archaeological remains and good regional pedostratigraphic correlation. The peak discharges of two palaeoflood events at the studied sites were estimated to be 16,560-17,930 m3/s. A correlation with the palaeoflood events identified in the other reaches shows that great floods occurred frequently during the episodes of 3200-2800 and 2000-1700 a BP along the upper Hanjiang River valley during the last 4000 years. These phases of palaeoflood events in central China are well correlated with the climatic variability identified by δ18O record in the stalagmites from the middle Yangtze River Basin and show apparent global linkages. Palaeoflood studies in a watershed scale also imply that strengthened human activities during the Shang dynasty (BCE 1600-1100) and Han dynasty (BCE206-CE265) may have caused accelerated soil erosion along the upper Hanjiang River valley.

Description, field test and data analysis of a controlled-source EM system (EM-60). [Leach Hot Springs, Grass Valley

Energy Technology Data Exchange (ETDEWEB)

Morrison, H.F.; Goldstein, N.E.; Hoversten, M.; Oppliger, G.; Riveros, C.

1978-10-01

The three sections describe the transmitter, the receiver, and data interpretations and indicate the advances made toward the development of a large moment electromagnetic (EM) system employing a magnetic dipole source. A brief description is given of the EM-60 transmitter, its general design, and the consideration involved in the selection of a practical coil size and weight for routine field operations. A programmable, multichannel, multi-frequency, phase-sensitive receiver is described. A field test of the EM-60, the data analysis and interpretation procedures, and a comparison between the survey results and the results obtained using other electrical techniques are presented. The Leach Hot Springs area in Grass Valley, Pershing County, Nevada, was chosen for the first field site at which the entire system would be tested. The field tests showed the system capable of obtaining well-defined sounding curves (amplitude and phase of magnetic fields) from 1 kHz down to 0.1 Hz. (MHR)

Magnetic field orientations in Saturn's upper ionosphere inferred from Voyager radio occultations

Science.gov (United States)

Hinson, D. P.

1984-01-01

The radio scintillations observed during occultations of Voyagers 1 and 2 by Saturn are analyzed to determine the morphology of plasma irregularities and hence the magnetic field orientation in Saturn's upper atmosphere. The measurement techniques, the weak scattering theory, and the method used to relate the observed radio scintillations to physical properties of the ionospheric irregularities are briefly described. Results on the spatial characteristics of the irregularities are presented, and the magnetic field orientation in Saturn's ionosphere is inferred. Although the occultation measurements generally confirm the accuracy of the Saturnian magnetic field model of Connerney et al. (1982), it is found that a small adjustment of the coefficients in that model's zonal harmonic expansion would remove the discrepancy between the model predictions and the measurements. A strategy for obtaining improved measurements of Saturn's magnetic field from radio occultation observations of scintillations and Faraday rotation using an orbiting spacecraft is briefly discussed.

Glacial evolution of the upper Gallego Valley (Panticosa mountains and Ribera de Biescas, Aragonese Pyrenees, Spain

Directory of Open Access Journals (Sweden)

Serrano-Cañadas, Enrique

1991-12-01

Full Text Available Glacial evolution in the upper Gallego Valley has been established by studying erosional and depositional land forms. Ten pulsations, related to five phases are described: Premaximal (F. G. 0, attributed to Middle Pleistocene; Peniglacier, with three expanding pulsations (F.G. 1, 2 y 3, is attributed to the Upper Pleistocene; Finipleniglacial with two phases of dynamic (F.G. 4 y 5' and climatic (F.G. 5 equilibrium associated with the Pleistocene deglaciation; high mountain phase (F.G. 6 y 7, with two morphogenetic episodes; and the Holocene pulses from the Little Ice Age.

[es] Evolución glaciar del Alto Gallego (Montañas de Panticosa y Ribera de Biescas, Pirineo aragonés. Se reconstruye la evolución glaciar del Alto Gallego a partir del estudio de las formas de erosión y acumulación glaciar. Se describen diez pulsaciones, correspondientes a cinco fases mayores: Premáximo (F.G.O., atribuido al Pleistoceno medio; Pleniglaciar, con tres pulsaciones de expansión (F.G. 1,2 y 3, del Pleistoceno reciente; el Finipleniglaciar,con fases de equilibrio dinámico (F.G. 4y 5'y climático (F.G.S, ligadas a la deglaciación pleistocena; las fases de alta montaña, con dos pulsaciones (F.G. 6 y 7, atribuidas al Tardiglaciar; y las fases holocenas, de la Pequeña Edad del Hielo.
[fr] Évolution glaciaire de Haut Gallego (montagnes de Panticosa et Rivage de Biescas, Pyrénées aragonaises. On étudie l'évolution glaciaire du Haut Gallego à partir de l'étude des formes d'érosion et accumulation glaciaire. On décrit dix pulsations, correspondant à cinq phases majeures: le Prémaximun (F.G. 0, attribué au Pléistocène moyen; le Pléniglaciaire avec trois pulsations d'expansion (F.G. 1, 2 et 3 attribuée au Pleistocene récent; le Pini-pléniglaciaire avec des phases d'équilibre dynamique (F.G. 4 et 5 et climatique (F.G. 5, liées à la déglaciation pléistocène; les phases de haute montagne, avec deux pulsations (F.G. 6 et 7 attribu

Vertical ozone transport in the Alps (VOTALP): the valley experiment 1996

Energy Technology Data Exchange (ETDEWEB)

Furger, M; Dommen, J; Graber, W K; Prevot, A; Poggio, L; Andreani, S; Keller, J; Portmann, W; Buerki, D; Erne, R; Richter, R; Tinguely, M [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

The EU project VOTALP started its valley campaign in the summer of 1996 in the Mesolcina valley. The influence of thermal circulations on ozone concentrations and on the exchange of ozone and its photochemical precursors between the valley atmosphere and the free troposphere above was the main focus of the study. PSI has participated with various measurement systems (conventional meteorological surface stations, radiosondes, scidar/DOAS systems, chemical analysers). An overview of PSI`s activities in the field campaign is given, and some preliminary results are presented. (author) 1 fig., 2 tabs., 2 refs.

Rate of progression of total, upper, and lower visual field defects in patients with open-angle glaucoma and high myopia.

Science.gov (United States)

Yoshino, Takaiko; Fukuchi, Takeo; Togano, Tetsuya; Sakaue, Yuta; Seki, Masaaki; Tanaka, Takayuki; Ueda, Jun

2016-03-01

We evaluated the rate of progression of total, upper, and lower visual field defects in patients with treated primary open-angle glaucoma (POAG) with high myopia (HM). Seventy eyes of 70 POAG patients with HM [≤-8 diopters (D)] were examined. The mean deviation (MD) slope and the upper and lower total deviation (upper TD, lower TD) slopes of the Humphrey Field Analyzer were calculated in patients with high-tension glaucoma (HTG) (>21 mmHg) versus normal-tension glaucoma (NTG) (≤21 mmHg). The mean age of all the patients (29 eyes with HTG and 41 eyes with NTG) was 48.5 ± 9.6 years. The MD slope, and upper and lower TD slopes of the HM group were compared to those of the non-HM group (NHM) (>-8 D) selected from 544 eyes in 325 age-matched POAG patients. In all, 70 eyes with HM and NHM were examined. The mean MD slope was -0.33 ± 0.33 dB/year in the HM, and -0.38 ± 0.49 dB/year in the NHM. There were no statistical differences between the HM and NHM (p = 0.9565). In the comparison of HTG versus NTG patients in both groups, the MD slope, and upper and lower TD slopes were similar. The rate of progression of total, upper, and lower visual field defects was similar among patients with HM and NHM. Although HM is a risk factor for the onset of glaucoma, HM may not be a risk factor for progression of visual field defects as assessed by the progression rate under treatment.

Angular dependence of the upper critical field in Bi sub 2 Sr sub 2 CuO sub 6 sub + subdelta

CERN Document Server

Vedeneev, S I

2002-01-01

The angular dependence of the upper critical field has been investigated in a wide range of temperatures in very high-quality Bi sub 2 Sr sub 2 CuO sub 6 sub + subdelta single crystals with critical temperature approx = 9 K in magnetic fields up to 28 T. Although the typical value of the normal state resistivity ratio approx = 10 sup 4 , the anisotropy ratio of the upper critical fields is much smaller. A model is proposed based on a strong anisotropy and a small transparency between superconducting layers

75 FR 62137 - Notice of Public Meeting; Proposed Alluvial Valley Floor Coal Exchange Public Interest Factors...

Science.gov (United States)

2010-10-07

... exchange Federal coal deposits for Alluvial Valley Floor (AVF) fee coal pursuant to the Federal Land Policy...; MTM-99236] Notice of Public Meeting; Proposed Alluvial Valley Floor Coal Exchange Public Interest... Alluvial Valley Floor Environmental Assessment can be viewed on the BLM's Miles City Field Office Web page...

VALDRIFT 1.0: A valley atmospheric dispersion model with deposition

Energy Technology Data Exchange (ETDEWEB)

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

1995-05-01

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

Size effects in many-valley fluctuations in semiconductors

International Nuclear Information System (INIS)

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

1995-08-01

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

Using SLAM to Look For the Dog Valley Fault, Truckee Area, California

Science.gov (United States)

Cronin, V. S.; Ashburn, J. A.; Sverdrup, K. A.

2014-12-01

The Truckee earthquake (9/12/1966, ML6.0) was a left-lateral event on a previously unrecognized NW-trending fault. The Prosser Creek and Boca Dams sustained damage, and the trace of the suspected causative fault passes near or through the site of the then-incomplete Stampede Dam. Another M6 earthquake occurred along the same general trend in 1948 with an epicenter in Dog Valley ~14 km to the NW of the 1966 epicenter. This trend is called the Dog Valley Fault (DVF), and its location on the ground surface is suggested by a prominent but broad zone of geomorphic lineaments near the cloud of aftershock epicenters determined for the 1966 event. Various ground effects of the 1966 event described by Kachadoorian et al. (1967) were located within this broad zone. The upper shoreface of reservoirs in the Truckee-Prosser-Martis basin are now exposed due to persistent drought. We have examined fault strands in a roadcut and exposed upper shoreface adjacent to the NE abutment of Stampede Dam. These are interpreted to be small-displacement splays associated with the DVF -- perhaps elements of the DVF damage zone. We have used the Seismo-Lineament Analysis Method (SLAM) to help us constrain the location of the DVF, based on earthquake focal mechanisms. Seismo-lineaments were computed, using recent revisions in the SLAM code (bearspace.baylor.edu/Vince_Cronin/www/SLAM/), for the 1966 main earthquake and for the better-recorded earthquakes of 7/3/1983 (M4) and 8/30/1992 (M3.2) that are inferred to have occurred along the DVF. Associated geomorphic analysis and some field reconnaissance identified a trend that might be associated with a fault, extending from the NW end of Prosser Creek Reservoir ~32° toward the Stampede Dam area. Triangle-strain analysis using horizontal velocities of local Plate Boundary Observatory GPS sites P146, P149, P150 and SLID indicates that the area rotates clockwise ~1-2°/Myr relative to the stable craton, as might be expected because the study area is

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

Science.gov (United States)

2012-06-05

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

Late Cenozoic tephrochronology, stratigraphy, geomorphology, and neotectonics of the Western Black Mountains Piedmont, Death Valley, California: Implications for the spatial and temporal evolution of the Death Valley fault zone

Science.gov (United States)

Knott, Jeffrey Rayburn

This study presents the first detailed tephrochronologic study of the central Death Valley area by correlation of a Nomlaki-like tuff (>3.35 Ma), tuffs of the Mesquite Spring family (3.1 -- 3.35 Ma), a tuff of the lower Glass Mountain family (1.86 -- 2.06 Ma), and tephra layers from the upper Glass Mountain family (0.8 -- 1.2 Ma), the Bishop ash bed (0.76 Ma), the Lava Creek B ash bed (~0.66 Ma), and the Dibekulewe ash bed (~0.51 Ma). Correlation of these tuffs and tephra layers provides the first reliable numeric-age stratigraphy for late Cenozoic alluvial fan and lacustrine deposits for Death Valley and resulted in the naming of the informal early to middle Pleistocene Mormon Ploint formation. Using the numeric-age stratigraphy, the Death Valley fault zone (DVFZ) is interpreted to have progressively stepped basinward since the late Pliocene at Mormon Point and Copper Canyon. The Mormon Point turtleback or low-angle normal fault is shown to have unequivocal late Quaternary slip at its present low angle dip. Tectonic geomorphic analysis indicates that the (DVFZ) is composed of five geomorphic segments with the most persistent segment boundaries being the en-echelon step at Mormon Point and the bedrock salient at Artists Drive. Subsequent geomorphic studies resulting from the numeric-age stratigraphy and structural relations include application of Gilberts field criteria to the benches at Mormon Point indicating that the upper bench is a lacustrine strandline and the remaining topographically-lower benches are fault scarps across the 160--185 ka lake abrasion platform. In addition, the first known application of cosmogenic 10Be and 26Al exposure dating to a rock avalanche complex south of Badwater yielded an age of 29.5 +/- 1.9 ka for the younger avalanche. The 28 meter offset of the older avalanche may be interpreted as post-160--185 ka yielding a 0.1 mm/year slip rate, or post-29.5 +/- 1.9 ka yielding a maximum slip rate of 0.9 nun/year for the DVFZ. A consequence

Large valley splitting in monolayer WS2 by proximity coupling to an insulating antiferromagnetic substrate

Science.gov (United States)

Xu, Lei; Yang, Ming; Shen, Lei; Zhou, Jun; Zhu, Tao; Feng, Yuan Ping

2018-01-01

Lifting the valley degeneracy is an efficient way to achieve valley polarization for further valleytronics operations. In this Rapid Communication, we demonstrate that a large valley splitting can be obtained in monolayer transition metal dichalcogenides by magnetic proximity coupling to an insulating antiferromagnetic substrate. As an example, we perform first-principles calculations to investigate the electronic structures of monolayer WS2 on the MnO(111) surface. Our calculation results suggest that a large valley splitting of 214 meV, which corresponds to a Zeeman magnetic field of 1516 T, is induced in the valence band of monolayer WS2. The magnitude of valley splitting relies on the strength of interfacial orbital hybridization and can be tuned continually by applying an external out-of-plane pressure and in-plane strain. More interestingly, we find that both spin and valley index will flip when the magnetic ordering of MnO is reversed. Besides, owing to the sizable Berry curvature and time-reversal symmetry breaking in the WS2/MnO heterostructure, a spin- and valley-polarized anomalous Hall current can be generated in the presence of an in-plane electric field, which allows one to detect valleys by the electrical approach. Our results shed light on the realization of valleytronic devices using the antiferromagnetic insulator as the substrate.

Xenoliths from Bunyaruguru volcanic field: Some insights into lithology of East African Rift upper mantle

Science.gov (United States)

Muravyeva, N. S.; Senin, V. G.

2018-01-01

The mineral composition of mantle xenoliths from kamafugites of the Bunyaruguru volcanic field has been determined. The major and some trace elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, Cr, Ni, Ba, Sr, La, Ce, Nd, Nb) has been analyzed in olivine, clinopyroxene, phlogopite, Cr-spinel, titanomagnetite, perovskite and carbonates of xenoliths and their host lavas. Bunyaruguru is one of three (Katwe-Kikorongo, Fort Portal and Bunyaruguru) volcanic fields included in the Toro-Ankole province located on the North end of the West Branch of the East African Rift. The xenoliths from three craters within the Bunyaruguru volcanic field revealed the different character of metasomatic alteration, reflecting the heterogeneity of the mantle on the kilometer scale. The most unusual finding was composite glimmerite-wehrlite xenolith from the crater Kazimiro, which contains the fresh primary high-Mg olivine with inclusions of Cr-spinel that had not been previously identified in this area. The different composition of phenocryst and xenolith minerals indicates that the studied xenoliths are not cumulus of enclosing magma, but the composition of xenoliths characterizes the lithology of the upper mantle of the area. The carbonate melt inclusions in olivine Fo90 demonstrate the existence of primary carbonatitic magmas in Bunyaruguru upper mantle. The results of texture and chemical investigation of the xenolith minerals indicate the time sequence of metasomatic alteration of Bunyaruguru upper mantle: MARID metasomatism at the first stage followed by carbonate metasomatism. The abundances of REE in perovskites from kamafugite are 2-4 times higher than similar values for xenolith. Therefore the kamafugite magma was been generated from a more enriched mantle source than the source of the xenoliths. The evaluation of P-T conditions formation of clinopyroxene xenolith revealed the range of pressure 20-65 kbar and the temperatures range 830-1040 °C. The pressure of clinopyroxene phenocryst

Spin- and valley-dependent electronic band structure and electronic heat capacity of ferromagnetic silicene in the presence of strain, exchange field and Rashba spin-orbit coupling

Science.gov (United States)

Hoi, Bui Dinh; Yarmohammadi, Mohsen; Kazzaz, Houshang Araghi

2017-10-01

We studied how the strain, induced exchange field and extrinsic Rashba spin-orbit coupling (RSOC) enhance the electronic band structure (EBS) and electronic heat capacity (EHC) of ferromagnetic silicene in presence of external electric field (EF) by using the Kane-Mele Hamiltonian, Dirac cone approximation and the Green's function approach. Particular attention is paid to investigate the EHC of spin-up and spin-down bands at Dirac K and K‧ points. We have varied the EF, strain, exchange field and RSOC to tune the energy of inter-band transitions and consequently EHC, leading to very promising features for future applications. Evaluation of EF exhibits three phases: Topological insulator (TI), valley-spin polarized metal (VSPM) and band insulator (BI) at given aforementioned parameters. As a new finding, we have found a quantum anomalous Hall phase in BI regime at strong RSOCs. Interestingly, the effective mass of carriers changes with strain, resulting in EHC behaviors. Here, exchange field has the same behavior with EF. Finally, we have confirmed the reported and expected symmetry results for both Dirac points and spins with the study of valley-dependent EHC.

Magnetotransport properties of 8-Pmmn borophene: effects of Hall field and strain.

Science.gov (United States)

Islam, S K Firoz

2018-07-11

The polymorph of 8-Pmmn borophene is an anisotropic Dirac material with tilted Dirac cones at two valleys. The tilting of the Dirac cones at two valleys are in opposite directions, which manifests itself via the valley dependent Landau levels in presence of an in-plane electric field (Hall field). The valley dependent Landau levels cause valley polarized magnetotransport properties in presence of the Hall field, which is in contrast to the monolayer graphene with isotropic non-tilted Dirac cones. The longitudinal conductivity and Hall conductivity are evaluated by using linear response theory in low temperature regime. An analytical approximate form of the longitudinal conductivity is also obtained. It is observed that the tilting of the Dirac cones amplifies the frequency of the longitudinal conductivity oscillation (Shubnikov-de Haas). On the other hand, the Hall conductivity exhibits graphene-like plateaus except the appearance of valley dependent steps which are purely attributed to the Hall field induced lifting of the valley degeneracy in the Landau levels. Finally we look into the different cases when the Hall field is applied to the strained borophene and find that valley dependency is fully dominated by strain rather than Hall field. Another noticeable point is that if the real magnetic field is replaced by the strain induced pseudo magnetic field then the electric field looses its ability to cause valley polarized transport.

Quaternary glaciation of the Tashkurgan Valley, Southeast Pamir

Science.gov (United States)

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

2012-07-01

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

Numerical analysis of air pollution in a combined field of land/sea breeze and mountain/valley wind

International Nuclear Information System (INIS)

Kitada, T.; Igarashi, K.; Owada, M.

1986-01-01

Air pollution in the presence of two types of local flows (i.e., land/sea breeze and mountain/valley wind) was studies by advection simulation of the cluster of hypothetical fluid particles, and transport/chemistry calculation employing a three-dimensional Eulerian model for 20 advected species and about 90 chemical reactions. Three-dimensional flow fields over the River Yahagi basin in Japan were estimated for 48 h using an objective method with routine wind observations. Those obtained showed characteristics of the combined local flows such that in the daytime sea breeze and valley wind tend to form one united flow with substantial wind velocity in the whole region and, in contrast, land breeze and mountain wind during the nighttime form two separated circulating flows with a clear weak-wind area between the two local flow regimes. The results of the advection simulation of fluid particles and the transport/chemistry calculation using those flows as inputs elucidated how the features found in the diurnally varying, complex local flows contribute to produce characteristic time-variations of the concentrations of both primary and secondary pollutants. Among others, dynamics of NO 2 , HNO 3 , PAN, O 3 , SO 2 , and SO 4 /sup =/ concentrations are discussed

Band-to-band tunneling in Γ valley for Ge source lateral tunnel field effect transistor: Thickness scaling

Science.gov (United States)

Jain, Prateek; Rastogi, Priyank; Yadav, Chandan; Agarwal, Amit; Chauhan, Yogesh Singh

2017-07-01

The direct and indirect valleys in Germanium (Ge) are separated by a very small offset, which opens up the prospect of direct tunneling in the Γ valley of an extended Ge source tunnel field effect transistor (TFET). We explore the impact of thickness scaling of extended Ge source lateral TFET on the band to band tunneling (BTBT) current. The Ge source is extended inside the gate by 2 nm to confine the tunneling in Ge only. We observe that as the thickness is scaled, the band alignment at the Si/Ge heterojunction changes significantly, which results in an increase in Ge to Si BTBT current. Based on density functional calculations, we first obtain the band structure parameters (bandgap, effective masses, etc.) for the Ge and Si slabs of varying thickness, and these are then used to obtain the thickness dependent Kane's BTBT tunneling parameters. We find that electrostatics improves as the thickness is reduced in the ultra-thin Ge film ( ≤ 10 nm). The ON current degrades as we scale down in thickness; however, the subthreshold slope ( S S AVG ) improves remarkably with thickness scaling due to subsurface BTBT. We predict that 8 nm thin devices offer the best option for optimized ON current and S S AVG .

Birds of the St. Croix River valley: Minnesota and Wisconsin

Science.gov (United States)

Faanes, Craig A.

1981-01-01

continuing expansion of the nearby Minneapolis-St. Paul metropolitan region has degraded or destroyed many woodlots, upland fields, and wetlands. In numerous instances, degradation of natural habitats has influenced the abundance and distribution of bird species. Because of these changes, both the Federal government and State Departments of Natural Resources have listed several species in various categories based on their current status. In the St. Croix River Valley, seven species are endangered, eight are threatened, and 29 are watch or priority status in either or both states. Data presented in this report are of value to land managers, land use specialists, and ornithologists, in assessing current and projected habitat alterations on the avifauna of this valley. The St. Croix River bisects a large region of western Wisconsin and east central Minnesota that exhibits a wide range of habitat types. This region supports not only birds, but many mammals, fishes, reptiles and amphibians, and several thousand species of vascular and nonvascular plants. The river itself is relatively clean through most of its course, and its natural flow is interrupted by only two small dams. Because the river lies within a 1-day drive of nearly 10 million people (Waters 1977), use of the area for recreational purposes is extremely heavy. Recreational pursuits include sunbathing, boating, and wild river kayaking in the summer, and ice fishing and cross-country skiing in the winter. The large number of unique and highly fragile habitats that exist there may never be compatible with the uses and abuses of the land that go with expanding human populations. Through the efforts of a number of citizens concerned with the quality of their environment and the foresightedness of several local, State, and Federal legislators, a portion of the upper St. Croix River Valley (hereafter termed 'the Valley') was established as a National Wild and Scenic River. Through establishment of t

Integrated Modeling and Carbonate Reservoir Analysis, Upper Jurassic Smackover Formation, Fishpond Field, Southwest Alabama

Science.gov (United States)

Owen, Alexander Emory

This field case study focuses on Upper Jurassic (Oxfordian) Smackover hydrocarbon reservoir characterization, modeling and evaluation at Fishpond Field, Escambia County, Alabama, eastern Gulf Coastal Plain of North America. The field is located in the Conecuh Embayment area, south of the Little Cedar Creek Field in Conecuh County and east of Appleton Field in Escambia County. In the Conecuh Embayment, Smackover microbial buildups commonly developed on Paleozoic basement paleohighs in an inner to middle carbonate ramp setting. The microbial and associated facies identified in Fishpond Field are: (F-1) peloidal wackestone, (F-2) peloidal packstone, (F-3) peloidal grainstone, (F-4) peloidal grainstone/packstone, (F-5) microbially-influenced wackestone, (F-6) microbially-influenced packstone, (F-7) microbial boundstone, (F-8) oolitic grainstone, (F-9) shale, and (F-10) dolomitized wackestone/packstone. The Smackover section consists of an alternation of carbonate facies, including F-1 through F-8. The repetitive vertical trend in facies indicates variations in depositional conditions in the area as a result of changes in water depth, energy conditions, salinity, and/or water chemistry due to temporal variations or changes in relative sea level. Accommodation for sediment accumulation also was produced by a change in base level due to differential movement of basement rocks as a result of faulting and/or subsidence due to burial compaction and extension. These changes in base level contributed to the development of a microbial buildup that ranges between 130-165 ft in thickness. The Fishpond Field carbonate reservoir includes a lower microbial buildup interval, a middle grainstone/packstone interval and an upper microbial buildup interval. The Fishpond Field has sedimentary and petroleum system characteristics similar to the neighboring Appleton and Little Cedar Creek Fields, but also has distinct differences from these Smackover fields. The characteristics of the

Upper cretaceous ammonite succession (Cenomanian - Coniacian) related to the upper Hondita and Loma Gorda Formations along the Bambuca creek, Aipe, Huila (Colombia, S.A.)

International Nuclear Information System (INIS)

Patarroyo, Pedro

2011-01-01

The Bambuca creek section (Aipe - Huila) shows a very good exposition of the upper Magdalena valley cretaceous deposits. To the upper part of the Hondita Formation were recollected acanthoceras sp. and rhynchostreon sp. of the upper Cenomanian. Related to the lower segment of the Loma Gorda Formation were found choffaticeras (c.) cf. segne, fagesia cf. catinus, neoptychites cf. andinus, mitonia gracilis, morrowitessp., nannovascoceras ? sp., quitmaniceras ? sp., benueites ? sp., paramammites ? sp. together with mytiloideskossmati, m. goppelnensis and anomia sp. of the lower Turonian. Following by hoplitoides sp. h. ingens,h. cf. lagiraldae, codazziceras ospinae, allocrioceras sp. that can be representing between the lower and middle Turonian. To the upper part of this segment were collected prionocycloceras sp. p. guayabanum, reesidites subtuberculatum, subprionotropis colombianus, mytiloides scupini, dydimotis sp., gauthiericerassp, anagaudryceras ? sp., eulophoceras jacobi, paralenticeras sieversi, hauericeras cf. madagascarensis, peroniceras (p.) subtricarinatum, forresteria (f.) sp, barroisiceras cf. onilahyense, ankinatsytes venezolanus, with upper Turonian to Coniacian. According to the related fauna it is not possible to establish the Cenomanian/Turonian and Turonian/Coniacian boundaries.

The effects of snow and salt on ice table stability in University Valley, Antarctica

Science.gov (United States)

Williams, Kaj; Heldmann, Jennifer L.; McKay, Christopher P.; Mellon, Michael T.

2018-01-01

The Antarctic Dry Valleys represent a unique environment where it is possible to study dry permafrost overlaying an ice-rich permafrost. In this paper, two opposing mechanisms for ice table stability in University Valley are addressed: i) diffusive recharge via thin seasonal snow deposits and ii) desiccation via salt deposits in the upper soil column. A high-resolution time-marching soil and snow model was constructed and applied to University Valley, driven by meteorological station atmospheric measurements. It was found that periodic thin surficial snow deposits (observed in University Valley) are capable of drastically slowing (if not completely eliminating) the underlying ice table ablation. The effects of NaCl, CaCl2 and perchlorate deposits were then modelled. Unlike the snow cover, however, the presence of salt in the soil surface (but no periodic snow) results in a slight increase in the ice table recession rate, due to the hygroscopic effects of salt sequestering vapour from the ice table below. Near-surface pore ice frequently forms when large amounts of salt are present in the soil due to the suppression of the saturation vapour pressure. Implications for Mars high latitudes are discussed.

Large magnetoresistance dips and perfect spin-valley filter induced by topological phase transitions in silicene

Science.gov (United States)

Prarokijjak, Worasak; Soodchomshom, Bumned

2018-04-01

Spin-valley transport and magnetoresistance are investigated in silicene-based N/TB/N/TB/N junction where N and TB are normal silicene and topological barriers. The topological phase transitions in TB's are controlled by electric, exchange fields and circularly polarized light. As a result, we find that by applying electric and exchange fields, four groups of spin-valley currents are perfectly filtered, directly induced by topological phase transitions. Control of currents, carried by single, double and triple channels of spin-valley electrons in silicene junction, may be achievable by adjusting magnitudes of electric, exchange fields and circularly polarized light. We may identify that the key factor behind the spin-valley current filtered at the transition points may be due to zero and non-zero Chern numbers. Electrons that are allowed to transport at the transition points must obey zero-Chern number which is equivalent to zero mass and zero-Berry's curvature, while electrons with non-zero Chern number are perfectly suppressed. Very large magnetoresistance dips are found directly induced by topological phase transition points. Our study also discusses the effect of spin-valley dependent Hall conductivity at the transition points on ballistic transport and reveals the potential of silicene as a topological material for spin-valleytronics.

The California Valley grassland

Science.gov (United States)

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

1990-01-01

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

Generation and electric control of spin-valley-coupled circular photogalvanic current in WSe2

Science.gov (United States)

Yuan, Hongtao; Hwang, Harold Y.; Cui, Yi

2015-03-01

Compared to the weak spin-orbit-interaction (SOI) in graphene, layered transitionmetal chalcogenides MX2 have heavy 4d/5d elements with strong atomic SOI, providing a unique way to extend functionalities of novel spintronics and valleytronics devices. Such a valley polarization achieved via valley-selective circular dichroism has been predicted theoretically and demonstrated with optical experiments in MX2 systems. Despite the exciting progresses, the generation of a valley/spin current by valley polarization in MX2 remains elusive and a great challenge. A spin/valley current in MX2 compounds caused by such a valley polarization has never been observed, nor its electric-field control. In this talk, we demonstrated, within an electric-double-layer transistor based on WSe2, the manipulation of a spin-coupled valley photocurrent whose direction and magnitude depend on the degree of circular polarization of the incident radiation and can be further greatly modulated with an external electric field. Such room temperature generation and electric control of valley/spin photocurrent provides a new property of electrons in MX2 systems, thereby enabling new degrees of control for quantum-confined spintronics devices. (In collaboration with S.C. Zhang, Y.L. Chen, Z.X. Shen, B Lian, H.J. Zhang, G Xu, Y Xu, B Zhou, X.Q. Wang, B Shen X.F. Fang) Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515. Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515.

Electrical resistivity tomography investigations in the ufita Valley (southern Italy.

Directory of Open Access Journals (Sweden)

C. Basso

2008-06-01

Full Text Available Several Electrical Resistivity Tomography (ERT surveys have been carried out to study the subsurface structural and sedimentary settings of the upper Ufita River valley, and to evaluate their efficiency to distinguish the geological boundary between shallow Quaternary sedimentary deposits and clayey bedrock characterized by moderate resistivity contrast. Five shallow ERTs were carried out across a morphological scarp running at the foot of the northeastern slope of the valley. This valley shoulder is characterized by a set of triangular facets, that some authors associated to the presence of a SW-dipping normal fault. The geological studies allow us to interpret the shallow ERTs results obtaining a resistivity range for each Quaternary sedimentary deposit. The tomographies showed the geometrical relationships of alluvial and slope deposits, having a maximum thickness of 30-40 m, and the morphology of the bedrock. The resistivity range obtained for each sedimentary body has been used for calibrating the tomographic results of one 3560m-long deep ERT carried out across the deeper part of the intramountain depression with an investigation depth of about 170 m. The deep resistivity result highlighted the complex alluvial setting, characterized by alternating fine grained lacustrine deposits and coarser gravelly fluvial sediments.

Extensional Structures on the Po Valley Side of the Northern Apennines

Science.gov (United States)

Bettelli, G.; Vannucchi, P.; Capitani, M.

2001-12-01

The present-day tectonics of the Northern Apennines is characterized by extension in the inner Tyrrhenian side and compression in the outer Po Valley-Adriatic side. The boundary separating the two domains, extensional and compressional, is still largely undetermined and mainly based on geophysical data (focal mechanisms of earthquakes). Map-scale extensional structures have been studied only along the Tyrrhenian side of the Northern Apennines (Tuscany), while along the Po Valley-Adriatic area the field studies concentrated on compressional features. A new, detailed field mapping of the Po Valley side of the Northern Apennines carried out in the last ten years within the Emilia Romagna Geological Mapping Program has shown the presence of a large extensional fault crossing the high Bologna-Modena-Reggio Emilia provinces, from the Sillaro to the Val Secchia valleys. This Sillaro-Val Secchia Normal Fault (SVSNF) is NW-SE trending, NE dipping and about 80 km long. The age, based on the younger displaced deposits, is post-Miocene. The SVSNF is a primary regional structure separating the Tuscan foredeep units from the Ligurian Units in the south-east sector of the Northern Apennines, and it is responsible for the exhumation of the Tuscan foredeep units along the Apennine water divide. The sub-vertical, SW-NE trending faults, formerly interpreted as strike slip, are transfer faults associated to the extensional structure. A geological cross-section across the SVSNF testifies a former thickness reduction and lamination of the Ligurian Units, as documented in the field, in the innermost areas of the Bologna-Modena-Reggio Emilia hills, implying the occurrence of a former extensional fault. These data indicate that the NE side of the water divide has already gone under extension reducing the compressional domain to the Po Valley foothills and plain. They can also help in interpreting the complex Apennines kinematics.

Theory of the upper critical field in antiferromagnetic superconductors

International Nuclear Information System (INIS)

Ro, C.; Levin, K.

1984-01-01

We compute the temperature T dependence of the upper critical field H/sub c/2(T) in antiferromagnetic (AF) superconductors. Using a strong-coupling formalism we explicitly treat the effects of the molecular field H/sub Q/, inelastic and elastic spin-fluctuation scattering and magnetic as well as nonmagnetic impurities. A sum rule is used to relate the T dependence of H/sub Q/ to that of the spin-fluctuation scattering. The decreased pair breaking observed below the Neel temperature in SmRh 4 B 4 and the increased pair breaking seen in the AF Chevrel compounds will both occur in our theory for a reasonable choice of parameters. For larger values of the dimensionless spin-exchange coupling constant N(0)J/sup c/f, spin-fluctuation-scattering effects dominate over those of H/sub Q/ and decreased pair breaking is observed below T/sub N/. For smaller values of the coupling constant, the converse is true. Impurity scattering is treated in a self-consistent fashion. As a consequence, the molecular field H/sub Q/ is altered by nonmagnetic impurities. This leads to important pair-breaking effects in H/sub c/2. A physical manifestation of this pair breaking is a qualitative change in the shape of the H/sub c/2 versus T curve, as nonmagnetic impurities are added. We give detailed predictions for the expected effects of these impurities on H/sub c/2 which can be tested experimentally

Photo-induced spin and valley-dependent Seebeck effect in the low-buckled Dirac materials

Science.gov (United States)

Mohammadi, Yawar

2018-04-01

Employing the Landauer-Buttiker formula we investigate the spin and valley dependence of Seebeck effect in low-buckled Dirac materials (LBDMs), whose band structure are modulated by local application of a gate voltage and off-resonant circularly polarized light. We calculate the charge, spin and valley Seebeck coefficients of an irradiated LBDM as functions of electronic doping, light intensity and the amount of the electric field in the linear regime. Our calculation reveal that all Seebeck coefficients always shows an odd features with respect to the chemical potential. Moreover, we show that, due to the strong spin-orbit coupling in the LBDMs, the induced thermovoltage in the irradiated LBDMs is spin polarized, and can also become valley polarized if the gate voltage is applied too. It is also found that the valley (spin) polarization of the induced thermovoltage could be inverted by reversing the circular polarization of light or reversing the direction the electric field (only by reversing the circular polarization of light).

Geomorphic controls on Pleistocene knickpoint migration in Alpine valleys

Science.gov (United States)

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

2014-05-01

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

A multi-dimensional analysis of the upper Rio Grande-San Luis Valley social-ecological system

Science.gov (United States)

Mix, Ken

The Upper Rio Grande (URG), located in the San Luis Valley (SLV) of southern Colorado, is the primary contributor to streamflow to the Rio Grande Basin, upstream of the confluence of the Rio Conchos at Presidio, TX. The URG-SLV includes a complex irrigation-dependent agricultural social-ecological system (SES), which began development in 1852, and today generates more than 30% of the SLV revenue. The diversions of Rio Grande water for irrigation in the SLV have had a disproportionate impact on the downstream portion of the river. These diversions caused the flow to cease at Ciudad Juarez, Mexico in the late 1880s, creating international conflict. Similarly, low flows in New Mexico and Texas led to interstate conflict. Understanding changes in the URG-SLV that led to this event and the interactions among various drivers of change in the URG-SLV is a difficult task. One reason is that complex social-ecological systems are adaptive, contain feedbacks, emergent properties, cross-scale linkages, large-scale dynamics and non-linearities. Further, most analyses of SES to date have been qualitative, utilizing conceptual models to understand driver interactions. This study utilizes both qualitative and quantitative techniques to develop an innovative approach for analyzing driver interactions in the URG-SLV. Five drivers were identified for the URG-SLV social-ecological system: water (streamflow), water rights, climate, agriculture, and internal and external water policy. The drivers contained several longitudes (data aspect) relevant to the system, except water policy, for which only discreet events were present. Change point and statistical analyses were applied to the longitudes to identify quantifiable changes, to allow detection of cross-scale linkages between drivers, and presence of feedback cycles. Agricultural was identified as the driver signal. Change points for agricultural expansion defined four distinct periods: 1852--1923, 1924--1948, 1949--1978 and 1979

Potential for a significant deep basin geothermal system in Tintic Valley, Utah

Science.gov (United States)

Hardwick, C.; Kirby, S.

2014-12-01

The combination of regionally high heat flow, deep basins, and permeable reservoir rocks in the eastern Great Basin may yield substantial new geothermal resources. We explore a deep sedimentary basin geothermal prospect beneath Tintic Valley in central Utah using new 2D and 3D models coupled with existing estimates of heat flow, geothermometry, and shallow hydrologic data. Tintic Valley is a sediment-filled basin bounded to the east and west by bedrock mountain ranges where heat-flow values vary from 85 to over 240 mW/m2. Based on modeling of new and existing gravity data, a prominent 30 mGal low indicates basin fill thickness may exceed 2 km. The insulating effect of relatively low thermal conductivity basin fill in Tintic Valley, combined with typical Great Basin heat flow, predict temperatures greater than 150 °C at 3 km depth. The potential reservoir beneath the basin fill is comprised of Paleozoic carbonate and clastic rocks. The hydrology of the Tintic Valley is characterized by a shallow, cool groundwater system that recharges along the upper reaches of the basin and discharges along the valley axis and to a series of wells. The east mountain block is warm and dry, with groundwater levels just above the basin floor and temperatures >50 °C at depth. The west mountain block contains a shallow, cool meteoric groundwater system. Fluid temperatures over 50 °C are sufficient for direct-use applications, such as greenhouses and aquaculture, while temperatures exceeding 140°C are suitable for binary geothermal power plants. The geologic setting and regionally high heat flow in Tintic Valley suggest a geothermal resource capable of supporting direct-use geothermal applications and binary power production could be present.

Resonant tunneling spectroscopy of valley eigenstates on a donor-quantum dot coupled system

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, T., E-mail: t.kobayashi@unsw.edu.au; Heijden, J. van der; House, M. G.; Hile, S. J.; Asshoff, P.; Simmons, M. Y.; Rogge, S. [Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney 2052 New South Wales (Australia); Gonzalez-Zalba, M. F. [Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Vinet, M. [Université Grenoble-Alpes and CEA, LETI, MINATEC, 38000 Grenoble (France)

2016-04-11

We report on electronic transport measurements through a silicon double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO{sub 2} interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160 and 240 μeV with an electric field dependence 1.2 ± 0.2 meV/(MV/m). A large valley splitting is an essential requirement for implementing a physical electron spin qubit in a silicon quantum dot.

Silurian extension in the Upper Connecticut Valley, United States and the origin of middle Paleozoic basins in the Québec embayment

Science.gov (United States)

Rankin, D.W.; Coish, R.A.; Tucker, R.D.; Peng, Z.X.; Wilson, S.A.; Rouff, A.A.

2007-01-01

Pre-Silurian strata of the Bronson Hill arch (BHA) in the Upper Connecticut Valley, NH-VT are host to the latest Ludlow Comerford Intrusive Suite consisting, east to west, of a mafic dike swarm with sheeted dikes, and an intrusive complex. The rocks are mostly mafic but with compositions ranging from gabbro to leucocratic tonalite. The suite is truncated on the west by the Monroe fault, a late Acadian thrust that carries rocks of the BHA westward over Silurian-Devonian strata of the Connecticut Valley-Gaspe?? trough (CVGT). Dikes intrude folded strata with a pre-intrusion metamorphic fabric (Taconian?) but they experienced Acadian deformation. Twenty fractions of zircon and baddeleyite from three sample sites of gabbrodiorite spanning nearly 40 km yield a weighted 207Pb/206Pb age of 419 ?? 1 Ma. Greenschist-facies dikes, sampled over a strike distance of 35 km, were tholeiitic basalts formed by partial melting of asthenospheric mantle, with little or no influence from mantle or crustal lithosphere. The dike chemistry is similar to mid-ocean ridge, within-plate, and back-arc basin basalts. Parent magmas originated in the asthenosphere and were erupted through severely thinned lithosphere adjacent to the CVGT. Extensive middle Paleozoic basins in the internides of the Appalachian orogen are restricted to the Que??bec embayment of the Laurentian rifted margin, and include the CVGT and the Central Maine trough (CMT), separated from the BHA by a Silurian tectonic hinge. The NE-trending Comerford intrusions parallel the CVGT, CMT, and the tectonic hinge, and indicate NW-SE extension. During post-Taconian convergence, the irregular margins of composite Laurentia and Avalon permitted continued collision in Newfoundland (St. Lawrence promontory) and coeval extension in the Que??bec embayment. Extension may be related to hinge retreat of the northwest directed Brunswick subduction complex and rise of the asthenosphere following slab break-off. An alternative hypothesis is

Greening Turner Valley

International Nuclear Information System (INIS)

Byfield, M.

2010-01-01

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

Valley-momentum locking in a graphene superlattice with Y-shaped Kekulé bond texture

Science.gov (United States)

Gamayun, O. V.; Ostroukh, V. P.; Gnezdilov, N. V.; Adagideli, İ.; Beenakker, C. W. J.

2018-02-01

Recent experiments by Gutiérrez et al (2016 Nat. Phys. 12 950) on a graphene-copper superlattice have revealed an unusual Kekulé bond texture in the honeycomb lattice—a Y-shaped modulation of weak and strong bonds with a wave vector connecting two Dirac points. We show that this so-called ‘Kek-Y’ texture produces two species of massless Dirac fermions, with valley isospin locked parallel or antiparallel to the direction of motion. In a magnetic field B, the valley degeneracy of the B-dependent Landau levels is removed by the valley-momentum locking but a B-independent and valley-degenerate zero-mode remains.

Characterization of down-valley winds in stable stratification from the KASCADE field campaign and WRF mesoscale simulations

International Nuclear Information System (INIS)

Duine, Gert-Jan

2015-01-01

This thesis investigates down-valley wind characteristics in complex terrain of moderate oro-graphy for a mid-latitude area. The work was motivated by safety regulation in the context of sanitary impact of the Cadarache centre on its close surroundings. Cadarache is one of the research centres of 'Commissariat a l'Energie Atomique et aux Energies Alternatives' (CEA), located in southeastern France. It is embedded in a small valley, the Cadarache Valley (CV), which is one of the tributaries of the larger Durance Valley (DV). The two valleys are distinct in width (1 - 2 vs. 5 km for CV and DV, respectively), length (5 vs. more than 60 km), depth (100 vs. 200 m and higher) and slope angle (1 degree vs. 0.2 degree on average along the valleys main axis), and therefore react differently under stable conditions. Stable stratifications regularly occur in the region due to frequent weak synoptic forcing and clear sky conditions. During such conditions, dilution of pollutants can become weak; this is one of the major motivations of the present study. To investigate the valley wind behaviour, the KASCADE (Katabatic winds and Stability over Cadarache for Dispersion of Effluents) campaign has been designed. It was conducted in the winter of 2013 including continuous observations (flux tower, Sodar and Cadarache observational network) covering a 3-month period and 23 intensive observation periods (IOPs). During the IOPs tethered balloon experiments were conducted and radio-soundings were launched. An IOP was carried out when weak synoptic forcing periods and clear skies were expected, started at 12 UTC and lasted 24 hours. A calibration experiment served for sensor correction purposes, resulting in a high quality data set of a well-documented campaign (http://kascade.sedoo.fr/). The valley flows at the local and regional scale are characterized from observations analysis and IOP simulations with the non-hydrostatic WRF model. The analysis shows that the Cadarache

Chiral filtration-induced spin/valley polarization in silicene line defects

Science.gov (United States)

Ren, Chongdan; Zhou, Benhu; Sun, Minglei; Wang, Sake; Li, Yunfang; Tian, Hongyu; Lu, Weitao

2018-06-01

The spin/valley polarization in silicene with extended line defects is investigated according to the chiral filtration mechanism. It is shown that the inner-built quantum Hall pseudo-edge states with identical chirality can serve as a chiral filter with a weak magnetic field and that the transmission process is restrained/strengthened for chiral states with reversed/identical chirality. With two parallel line defects, which act as natural chiral filtration, the filter effect is greatly enhanced, and 100% spin/valley polarization can be achieved.

Robinson Rancheria Strategic Energy Plan; Middletown Rancheria Strategic Energy Plan, Scotts Valley Rancheria Strategic Energy Plan, Elem Indian Colony Strategic Energy Plan, Upperlake Rancheria Strategic Energy Plan, Big Valley Rancheria Strategic Energy Plan

Energy Technology Data Exchange (ETDEWEB)

McGinnis and Associates LLC

2008-08-01

The Scotts Valley Band of Pomo Indians is located in Lake County in Northern California. Similar to the other five federally recognized Indian Tribes in Lake County participating in this project, Scotts Valley Band of Pomo Indians members are challenged by generally increasing energy costs and undeveloped local energy resources. Currently, Tribal decision makers lack sufficient information to make informed decisions about potential renewable energy resources. To meet this challenge efficiently, the Tribes have committed to the Lake County Tribal Energy Program, a multi Tribal program to be based at the Robinson Rancheria and including The Elem Indian Colony, Big Valley Rancheria, Middletown Rancheria, Habematolel Pomo of Upper Lake and the Scotts Valley Pomo Tribe. The mission of this program is to promote Tribal energy efficiency and create employment opportunities and economic opportunities on Tribal Lands through energy resource and energy efficiency development. This program will establish a comprehensive energy strategic plan for the Tribes based on Tribal specific plans that capture economic and environmental benefits while continuing to respect Tribal cultural practices and traditions. The goal is to understand current and future energy consumption and develop both regional and Tribe specific strategic energy plans, including action plans, to clearly identify the energy options for each Tribe.

Avulsions, channel evolution and floodplain sedimentation rates of the anastomosing upper Columbia River, British Columbia, Canada

NARCIS (Netherlands)

Makaske, B.; Smith, D.G.; Berendsen, H.J.A.

2002-01-01

Ages of channels of the anastomosing upper Columbia River, south-eastern British Columbia, Canada, were investigated in a cross-valley transect by C-14 dating of subsurface floodplain organic material from beneath levees. The avulsion history within the transect was deduced from these data, and

Analysis of overdeepened valleys using the digital elevation model of the bedrock surface of Northern Switzerland

Energy Technology Data Exchange (ETDEWEB)

Jordan, P.

2010-11-15

Based on surface and borehole information, together with pre-existing regional and local interpretations, a 7,150 square kilometre Raster Digital Elevation Model (DEM) of the bedrock surface of northern Switzerland was constructed using a 25 m cell size. This model represents a further important step in the understanding of Quaternary sediment distribution and is open to a broad field of application and analysis, including hydrogeological, geotechnical and geophysical studies as well as research in the field of Pleistocene landscape evolution. An analysis of the overdeepened valleys in the whole model area and, more specifically in the Reuss area, shows that, in most cases, overdeepening is restricted to the areas covered by the Last Glaciation Maximum (LGM). However, at various locations relatively narrow overdeepened valleys outreach the tongue basins and the LGM ice shield limits. Therefore, an earlier and further-reaching glacial event has probably contributed significantly to the overdeepening of these valleys. No significant overdeepening has been identified downstream of Boettstein (Aare) and Kaiserstuhl (Rhine), although the ice extended considerably further downstream, at least during the most extensive glaciation. Except for the bedrock between Brugg and Boettstein, no overdeepened valleys are found significantly north of the outcrop of Mesozoic limestone of the Folded and Tabular Jura. A detailed analysis of the Reuss area shows that the Lake and Suhre valleys are separated from the Emmen-Gisikon Reuss valley basin by a significant bedrock barrier. The individual bedrock valleys are divided into several sub-basins, indicating a multiphase evolution of the valleys. Some of the swells or barriers separating the sub-basins coincide with known late LGM retreat stages. In the Suhre valley, an old fluvial valley floor with restricted overdeepened sections is documented. (author)

Testing a Mars science outpost in the Antarctic dry valleys

Science.gov (United States)

Andersen, D. T.; Mckay, C. P.; Wharton, R. A.; Rummel, J. D.

1992-01-01

Field research conducted in the Antarctic has been providing insights about the nature of Mars in the science disciplines of exobiology and geology. Located in the McMurdo Dry Valleys of southern Victoria Land (160 deg and 164 deg E longitude and 76 deg 30 min and 78 deg 30 min S latitude), research outposts are inhabited by teams of 4-6 scientists. It is proposed that the design of these outposts be expanded to enable meaningful tests of many of the systems that will be needed for the successful conduct of exploration activities on Mars. Although there are some important differences between the environment in the Antarctic dry valleys and on Mars, the many similarities and particularly the field science activities, make the dry valleys a useful terrestrial analog to conditions on Mars. Three areas have been identified for testing at a small science outpost in the dry valleys: (1) studying human factors and physiology in an isolated environment; (2) testing emerging technologies (e.g. innovative power management systems, advanced life support facilities including partial bioregenerative life support systems for water recycling and food growth, telerobotics, etc.); and (3) conducting basic scientific research that will enhance understanding of Mars while contributing to the planning for human exploration. It is suggested that an important early result of a Mars habitat program will be the experience gained by interfacing humans and their supporting technology in a remote and stressful environment.

Induced dynamic nonlinear ground response at Gamer Valley, California

Science.gov (United States)

Lawrence, Z.; Bodin, P.; Langston, C.A.; Pearce, F.; Gomberg, J.; Johnson, P.A.; Menq, F.-Y.; Brackman, T.

2008-01-01

We present results from a prototype experiment in which we actively induce, observe, and quantify in situ nonlinear sediment response in the near surface. This experiment was part of a suite of experiments conducted during August 2004 in Garner Valley, California, using a large mobile shaker truck from the Network for Earthquake Engineering Simulation (NEES) facility. We deployed a dense accelerometer array within meters of the mobile shaker truck to replicate a controlled, laboratory-style soil dynamics experiment in order to observe wave-amplitude-dependent sediment properties. Ground motion exceeding 1g acceleration was produced near the shaker truck. The wave field was dominated by Rayleigh surface waves and ground motions were strong enough to produce observable nonlinear changes in wave velocity. We found that as the force load of the shaker increased, the Rayleigh-wave phase velocity decreased by as much as ???30% at the highest frequencies used (up to 30 Hz). Phase velocity dispersion curves were inverted for S-wave velocity as a function of depth using a simple isotropic elastic model to estimate the depth dependence of changes to the velocity structure. The greatest change in velocity occurred nearest the surface, within the upper 4 m. These estimated S-wave velocity values were used with estimates of surface strain to compare with laboratory-based shear modulus reduction measurements from the same site. Our results suggest that it may be possible to characterize nonlinear soil properties in situ using a noninvasive field technique.

Disorder and the upper critical field of Nb3Ge

International Nuclear Information System (INIS)

Habermeier, H.U.

1981-01-01

The upper critical field, H/sub c2/, as determined from experimental values of T/sub c/ and (dH/sub c2//dT)/sub Tc/, has been investigated in Nb 3 Ge superconducting thin films with different degree of structural disorder. An increase of H/sub c2/(O) up to 36.9 T was found for samples with resistivities ranging from 40 to 60 /mu/sub/ OMEGA/cm and a decrease of H/sub c2/(O) to 5.7 T for /rho/.150 /mu/sub/ OMEGA/cm. Based on the Ginsburg-Landau solution for H/sub c2/(O) and the change of the coherence length with the electron mean free path a model is presented which describes the change of H/sub c2/(O) with resistivity, qualitatively. 15 refs

NNSS Soils Monitoring: Plutonium Valley (CAU 366)

International Nuclear Information System (INIS)

Miller, Julianne J.; Mizell, Steve A.; Nikolich, George; Campbell, Scott

2012-01-01

The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA), Nevada Site Office (NSO), Environmental Restoration Soils Activity has authorized the Desert Research Institute (DRI) to conduct field assessments of potential sediment transport of contaminated soil from Corrective Action Unit (CAU) 366, Area 11 Plutonium Valley Dispersion Sites Contamination Area (CA) during precipitation runoff events.

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

Science.gov (United States)

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

2017-05-10

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

Formation of the Wiesloch Mississippi Valley-type Zn-Pb-Ag deposit in the extensional setting of the Upper Rhinegraben, SW Germany

Science.gov (United States)

Pfaff, Katharina; Hildebrandt, Ludwig H.; Leach, David L.; Jacob, Dorrit E.; Markl, Gregor

2010-01-01

The Mississippi Valley-type (MVT) Zn-Pb-Ag deposit in the Wiesloch area, Southwest Germany, is controlled by graben-related faults of the Upper Rhinegraben. Mineralization occurs as vein fillings and irregular replacement ore bodies consisting of sphalerite, banded sphalerite, galena, pyrite, sulfosalts (jordanite and geocronite), barite, and calcite in the Middle Triassic carbonate host rock. Combining paragenetic information, fluid inclusion investigations, stable isotope and mineral chemistry with thermodynamic modeling, we have derived a model for the formation of the Wiesloch deposit. This model involves fluid mixing between ascending hot brines (originating in the crystalline basement) with sedimentary formation waters. The ascending brines originally had a near-neutral pH (around 6) and intermediate oxidation state, reflecting equilibrium with granites and gneisses in the basement. During fluid ascent and cooling, the pH of the brine shifted towards more acidic (around 4) and the oxidation state increased to conditions above the hematite-magnetite buffer. These chemical characteristics contrast strongly with those of the pore and fracture fluid residing in the limestone aquifer, which had a pH between 8 and 9 in equilibrium with calcite and was rather reduced due to the presence of organic matter in the limestone. Mixing between these two fluids resulted in a strong decrease in the solubility of silver-bearing sphalerite and galena, and calcite. Besides Wiesloch, several Pb-Zn deposits are known along the Upper Rhinegraben, including hydrothermal vein-type deposits like Badenweiler and the Michael mine near Lahr. They all share the same fluid origin and formation process and only differ in details of their host rock and fluid cooling paths. The mechanism of fluid mixing also seems to be responsible for the formation of other MVT deposits in Europe (e.g., Reocin, Northern Spain; Treves, Southern France; and Cracow-Silesia, Poland), which show notable

Characterize the hydrogeological properties and probe the stress field in Salt Lake Valley, Utah using SAR imagery

Science.gov (United States)

Hu, X.; Lu, Z.; Barbot, S.; Wang, T.

2017-12-01

Aquifer skeletons deform actively in response to the groundwater redistribution and hydraulic head changes with varied time scales of delay and sensitivity, that can also, in some instances, trigger earthquakes. However, determining the key hydrogeological properties and understanding the interactions between aquifer and seismicity generally requires the analysis of dense water level data combined with expensive drilling data (borehole breakouts). Here we investigate the spatiotemporal correlation among ground motions, hydrological changes, earthquakes, and faults in Salt Lake Valley, Utah, based on InSAR observations from ENVISAT ASAR (2004-2010) and Sentinel-1A (2015-2016). InSAR results show a clear seasonal and long-term correlation between surface uplift/subsidence and groundwater recharge/discharge, with evidence for an average net uplift of 15 mm/yr for a period of 7 years. The long-term uplift, remarkably bounded by faults, reflects a net increase in pore pressure associated with prolonged water recharge probably decades ago. InSAR-derived ground deformation and its correlation with head variations allow us to quantify hydrogeological properties - decay coefficient, storage coefficient, and bulk compressibility. We also model the long-term deformation using a shallow vertical shearing reservoir to constrain its thickness and strain rate. InSAR-derived deformation help reveal the coupled hydrological and tectonic processes in Salt Lake Valley: the embedded faults disrupt the groundwater flow and partition the hydrological units, and the pore pressure changes rearrange the aquifer skeleton and modulate the stress field, which may affect the basin-wide seismicity.

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

Science.gov (United States)

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

2012-01-01

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

Brief Communication: Intertooth and Intrafacet Dental Microwear Variation in an Archaeological Sample of Modern Humans From the Jordan Valley

OpenAIRE

Mahoney, Patrick

2006-01-01

Dental microwear was recorded in a Bronze-Iron Age (3570–3000 BP) sample of modern humans recovered from Tell es-Sa'idiyeh in the Jordan Valley. Microwear patterns were compared between mandibular molars, and between the upper and lower part of facet 9. The comparison revealed a greater frequency of pits and shorter scratches on the second and third molars, compared to the first. Pit frequency also increased on the lower part of the facet on the first molar, compared to the upper part. These ...

Measurements of the Magnetic Field of the Upper Chromosphere with Polarimetry

Science.gov (United States)

Rachmeler, Laurel; Mckenzie, David; Winebarger, Amy; Kobayashi, Ken; Ishikawa, Ryohko; Kubo, Masahito; Narukage, Noriyuki; Bueno, Trujillo, Javier; Auchere, Frederic

2017-01-01

A major remaining challenge for heliophysics is to decipher the magnetic structure of the chromosphere. The chromosphere is the critical interface between the Sun's photosphere and corona: it contains more mass than the entire interplanetary heliosphere, requires a heating rate that is larger than that of the corona, and mediates all the energy driving the solar wind, solar atmospheric heating and solar eruptions. While measurements of the magnetic field in the photosphere are routine, the chromosphere poses several extra challenges. The magnetically sensitive lines formed in the upper chromosphere are in the ultraviolet, so space-based observations are required. The lines are often formed over a range of heights, sampling different plasma which complicates the inversion process. These lines are sensitive to the magnetic field via polarized light that is created or modified through the Hanle and Zeeman effects. There are a few observations of these lines, and a significant challenge remains in extracting the magnetic field from the polarization measurements, as detailed model atmospheres with advanced radiative transfer physics are needed. Real progress is obtained by a simultaneous improvement in both the observational side and the modeling side. We present information on the CLASP (Chromospheric LAyer Spectro-Polarimeter) sounding rocket program, and future prospects for these types of measurements.

Origin of planation surfaces in the hinterland of Šumljak sedimentary bodies in Rebrnice (Upper Vipava Valley, SW Slovenia

Directory of Open Access Journals (Sweden)

Tomislav Popit

2017-12-01

Full Text Available The Rebrnice area forms the north eastern slopes of the Upper Vipava Valley and is located between Karst plateau to the southwest and the Nanos plateau to the northeast. The Rebrnice slopes are geomorphologically defied by a thrust front of Mesozoic carbonates over Tertiary flsch deposits and are characterised by a variety of polygenetic landslides (being the most prominent geomorphological features. Among them, the three Šumljak sedimentary bodies of fossil landslides (approximately 0.56 km² in area comprise carbonate gravels and breccia. The most distinctive geomorphological element is the planation surface of the carbonate breccia blocks positioned in the hinterland of the Šumljak sedimentary bodies. Another feature is the presence of local escarpments (steep scarps defiing the border between the planation surface in the hinterland and sedimentary bodies. Our research suggests that the whole area in the hinterland of the Šumljak sedimentary bodies form part of a deep-seated rotational landslide formed of carbonate breccia. On the basis of the dipping of the breccia beds, in particular parts of the rotational blocks, the rotation can reach up to 60°. Planation surfaces developed above the curved, sliding plane in the central part and/or slightly outer part of the landslide. Steep scarps on the external parts of the planation surface represent the main scarps of the Šumljak sedimentary bodies. We propose that these bodies originated from the remobilization of material accumulated in outer parts of large-scale rotational slides and its transportation further downslope, mostly by rock avalanches.

Vertical field MR imaging of upper thorax and spine in small children

International Nuclear Information System (INIS)

Brockstedt, S.; Malmgren, N.; Malmgren, L.; Ivarsson, M.L.; Larsson, E.M.; Holtaas, S.; Staahlberg, F.

1993-01-01

To improve image quality in a vertical field MR imaging unit, operating at low field strength (0.3 T), we have designed a half-elliptical coil for use in the upper thoracic region of small children. Our intention was also to shorten the examination time, which until now has been long, because several scans with different coils have been necessary to cover the thoracic region. The experimental coil is designed so that a child's shoulders fit into the central region. The coil consists of 2 serially connected cable-loops, mounted on a foam rubber vest. The coil performance was tested in a phantom and improvements relative to standard coils were demonstrated in in vivo studies. The results indicate that by using the half-elliptical coil, the signal-to-noise (S/N) ratio can be improved by a factor of 2 to 3 in the thoracic region of a child. (orig.)

Ground water in Dale Valley, New York

Science.gov (United States)

Randall, Allan D.

1979-01-01

Dale Valley is a broad valley segment, enlarged by glacial erosion, at the headwaters of Little Tonawanda Creek near Warsaw , New York. A thin, shallow alluvial aquifer immediately underlies the valley floor but is little used. A deeper gravel aquifer, buried beneath many feet of lake deposits, is tapped by several industrial wells. A finite-difference digital model treated the deep aquifer as two-dimensional with recharge and discharge through a confining layer. It was calibrated by simulating (1) natural conditions, (2) an 18-day aquifer test, and (3) 91 days of well-field operation. Streamflow records and model simulations suggest that in moderately wet years such as 1974, a demand of 750 gallons per minute could be met by withdrawal from the creek and from the aquifer without excessive drawdown at production wells or existing domestic wells. With reasonable but unverified model adjustments to simulate an unusually dry year, the model predicts that a demand of 600 gallons per minute could be met from the same sources. Water high in chloride has migrated from bedrock into parts of the deep aquifer. Industrial pumpage, faults in the bedrock, and the natural flow system may be responsible. (Woodard-USGS)

Upper critical magnetic field of superconducting films with magnetic impurities

International Nuclear Information System (INIS)

Lemberger, T.R.

1978-01-01

The upper critical magnetic field, H/sub c2/(T), of In-Mn and Pb-Mn alloy films was measured. H/sub c2/ was determined from the resistance of the films. The results were compared with the theory of Fulde and Maki. This theory assumes that the electron-phonon coupling is weak, and that the interaction between the impurity spins and the conduction electron spins is weak. The theory predicts that the pair-breaking effect of the magnetic impurities is temperature-independent, and that the pair-breaking effects of the magnetic impurities and the applied magnetic field are additive. Furthermore, it predicts explicitly the temperature dependence of H/sub c2/. The temperature dependence of H/sub c2/ for the In-Mn alloy films is well described by the Fulde-Maki theory, despite the moderately strong electron-phonon coupling and the strong interaction between the impurity spins and the conduction electron spins. The temperature dependence of H/sub c2/ for the Pb-Mn alloy films is not well described by the Fulde-Maki theory, probably due to the strong electron-phonon coupling in Pb. However, even without a quantitatively correct theory, one can conclude from the Pb-Mn data that the pair-breaking effect of the magnetic impurities is temperature independent, and that the pair-breaking effects of the magnetic impurities and the applied magnetic field are additive. For some of the Pb-Mn alloy films, there was a region of positive curvature in H/sub c2/(T) near the zero-field transition temperature. This positive curvature is not understood

GIS- and field based mapping of geomorphological changes in a glacier retreat area: A case study from the Kromer valley, Silvretta Alps (Austria)

Science.gov (United States)

Guttmann, Markus; Pöppl, Ronald

2017-04-01

Global warming results in an ongoing retreat of Alpine glaciers, leaving behind large amounts of easily erodible sediments. As a consequence processes like rockfalls, landslides and debris flows as well as fluvial processes occur more frequently in pro- and paraglacial areas, often involving catastrophic consequences for humans and infrastructure in the affected valleys. The main objective of the presented work was to map and spatially quantify glacier retreat and geomorphological changes in the Kromer valley, Silvretta Alps (Austria) by applying GIS- and field-based geomorphological mapping. In total six geomorphological maps (1950s, 1970s, 2001, 2006, 2012, and 2016) were produced and analyzed in the light of the study aim. First results have shown a significant decrease of total glaciated area from 96 ha to 53 ha which was accompanied by increased proglacial geomorphic activity (i.e. fluvial processes, rockfalls, debris flows, shallow landslides) in the last 15 years. More detailed results will be presented at the EGU General Assembly 2017.

The hydrogeology of the Tully Valley, Onondaga County, New York: an overview of research, 1992-2012

Science.gov (United States)

Kappel, William M.

2014-01-01

Onondaga Creek begins approximately 15 miles south of Syracuse, New York, and flows north through the Onondaga Indian Nation, then through Syracuse, and finally into Onondaga Lake in central New York. Tully Valley is in the upper part of the Onondaga Creek watershed between U.S. Route 20 and the Valley Heads end moraine near Tully, N.Y. Tully Valley has a history of several unusual hydrogeologic phenomena that affected past land use and the water quality of Onondaga Creek; the phenomena are still present and continue to affect the area today (2014). These phenomena include mud volcanoes or mudboils, landslides, and land-surface subsidence; all are considered to be naturally occurring but may also have been influenced by human activity. The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency and the Onondaga Lake Partnership, began a study of the Tully Valley mudboils beginning in October 1991 in hopes of understanding (1) what drives mudboil activity in order to remediate mudboil influence on the water quality of Onondaga Creek, and (2) land-surface subsidence issues that have caused a road bridge to collapse, a major pipeline to be rerouted, and threatened nearby homes. Two years into this study, the 1993 Tully Valley landslide occurred just over 1 mile northwest of the mudboils. This earth slump-mud flow was the largest landslide in New York in more than 70 years (Fickies, 1993); this event provided additional insight into the geology and hydrology of the valley. As the study of the Tully Valley mudboils progressed, other unusual hydrogeologic phenomena were found within the Tully Valley and provided the opportunity to perform short-term, small-scale studies, some of which became graduate student theses—Burgmeier (1998), Curran (1999), Morales-Muniz (2000), Baldauf (2003), Epp (2005), Hackett, (2007), Tamulonis (2010), and Sinclair (2013). The unusual geology and hydrology of the Tully Valley, having been investigated for

Holocene environmental change and archaeology, Yangtze River Valley, China: Review and prospects

Directory of Open Access Journals (Sweden)

Li Wu

2012-11-01

Full Text Available Holocene environmental change and environmental archaeology are important components of an international project studying the human-earth interaction system. This paper reviews the progress of Holocene environmental change and environmental archaeology research in the Yangtze River Valley over the last three decades, that includes the evolution of large freshwater lakes, Holocene transgression and sea-level changes, Holocene climate change and East Asian monsoon variation, relationship between the rise and fall of primitive civilizations and environmental changes, cultural interruptions and palaeoflood events, as well as relationship between the origin of agriculture and climate change. These research components are underpinned by the dating of lacustrine sediments, stalagmites and peat to establish a chronology of regional environmental and cultural evolution. Interdisciplinary and other environment proxy indicators need to be used in comparative studies of archaeological site formation and natural sedimentary environment in the upper, middle and lower reaches of the Yangtze River Valley. Modern technology such as remote sensing, molecular bioarchaeology, and virtual reality, should be integrated with currently used dating, geochemical, sedimentological, and palaeobotanical methods of analysis in environmental archaeology macro- and micro-studies, so as to provide a greater comprehensive insight into Holocene environmental and cultural interaction and change in the Yangtze River Valley area.

The essential spectrum of Schroedinger operators with asymptotically constant magnetic fields on the Poincare upper-half plane

International Nuclear Information System (INIS)

Inahama, Yuzuru; Shirai, Shin-ichi

2003-01-01

We study the essential spectrum of the magnetic Schroedinger operators on the Poincare upper-half plane and establish a hyperbolic analog of Iwatsuka's result [J. Math. Kyoto Univ. 23(3), 475-480 (1983)] on the stability of the essential spectrum under perturbations from constant magnetic fields

Nonvariceal upper gastrointestinal bleeding

International Nuclear Information System (INIS)

Burke, Stephen J.; Weldon, Derik; Sun, Shiliang; Golzarian, Jafar

2007-01-01

Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding. (orig.)

Nonvariceal upper gastrointestinal bleeding

Energy Technology Data Exchange (ETDEWEB)

Burke, Stephen J.; Weldon, Derik; Sun, Shiliang [University of Iowa, Department of Radiology, Iowa, IA (United States); Golzarian, Jafar [University of Iowa, Department of Radiology, Iowa, IA (United States); University of Iowa, Department of Radiology, Carver College of Medicine, Iowa, IA (United States)

2007-07-15

Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding. (orig.)

Epitaxial Single-Layer MoS2 on GaN with Enhanced Valley Helicity

KAUST Repository

Wan, Yi

2017-12-19

Engineering the substrate of 2D transition metal dichalcogenides can couple the quasiparticle interaction between the 2D material and substrate, providing an additional route to realize conceptual quantum phenomena and novel device functionalities, such as realization of a 12-time increased valley spitting in single-layer WSe2 through the interfacial magnetic exchange field from a ferromagnetic EuS substrate, and band-to-band tunnel field-effect transistors with a subthreshold swing below 60 mV dec−1 at room temperature based on bilayer n-MoS2 and heavily doped p-germanium, etc. Here, it is demonstrated that epitaxially grown single-layer MoS2 on a lattice-matched GaN substrate, possessing a type-I band alignment, exhibits strong substrate-induced interactions. The phonons in GaN quickly dissipate the energy of photogenerated carriers through electron–phonon interaction, resulting in a short exciton lifetime in the MoS2/GaN heterostructure. This interaction enables an enhanced valley helicity at room temperature (0.33 ± 0.05) observed in both steady-state and time-resolved circularly polarized photoluminescence measurements. The findings highlight the importance of substrate engineering for modulating the intrinsic valley carriers in ultrathin 2D materials and potentially open new paths for valleytronics and valley-optoelectronic device applications.

Epitaxial Single-Layer MoS2 on GaN with Enhanced Valley Helicity

KAUST Repository

Wan, Yi; Xiao, Jun; Li, Jingzhen; Fang, Xin; Zhang, Kun; Fu, Lei; Li, Pan; Song, Zhigang; Zhang, Hui; Wang, Yilun; Zhao, Mervin; Lu, Jing; Tang, Ning; Ran, Guangzhao; Zhang, Xiang; Ye, Yu; Dai, Lun

2017-01-01

Engineering the substrate of 2D transition metal dichalcogenides can couple the quasiparticle interaction between the 2D material and substrate, providing an additional route to realize conceptual quantum phenomena and novel device functionalities, such as realization of a 12-time increased valley spitting in single-layer WSe2 through the interfacial magnetic exchange field from a ferromagnetic EuS substrate, and band-to-band tunnel field-effect transistors with a subthreshold swing below 60 mV dec−1 at room temperature based on bilayer n-MoS2 and heavily doped p-germanium, etc. Here, it is demonstrated that epitaxially grown single-layer MoS2 on a lattice-matched GaN substrate, possessing a type-I band alignment, exhibits strong substrate-induced interactions. The phonons in GaN quickly dissipate the energy of photogenerated carriers through electron–phonon interaction, resulting in a short exciton lifetime in the MoS2/GaN heterostructure. This interaction enables an enhanced valley helicity at room temperature (0.33 ± 0.05) observed in both steady-state and time-resolved circularly polarized photoluminescence measurements. The findings highlight the importance of substrate engineering for modulating the intrinsic valley carriers in ultrathin 2D materials and potentially open new paths for valleytronics and valley-optoelectronic device applications.

Depositional environments of the uranium bearing Cutler Formations, Lisbon Valley, Utah

International Nuclear Information System (INIS)

Campbell, J.A.; Steele-Mallory, B.A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67 0 W. on the average, whereas marine currents moved sediment S. 36 0 E. and N. 24 0 W., and wind transported sand S. 80 0 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little

Depositional environments of the uranium-bearing Cutler Formations, Lisbon Valley, Utah

Science.gov (United States)

Campbell, John A.; Steele-Mallory, Brenda A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67? W. on the the average, whereas marine currents moved sediment S. 36? E. and N. 24? W., and wind transported sand S. 800 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little.

Torrential floods: A potential hazard at the Aburra valley

International Nuclear Information System (INIS)

Caballero Acosta, Jose Humberto

2011-01-01

Torrential foods are a type of mass movement generally moving through the channels of the creeks, leading to transport large volumes of sediment and debris, unsafe speeds for the people and infrastructure located in areas of accumulation of mountain watersheds susceptible to this phenomenon. Although there is no adequate historical record of such events to the valley of Aburra, if there are some experiences that validate the growing concern about this threat in the region. The geomorphologic and climatic conditions in the valley allow us to call attention to this problem, especially when we consider that the basins have been practically occupied in low or accumulation areas are being subjected to strong constructive pressure, without concern in the negative impact that the inappropriate intervention, can have in the lowlands. It requires interdisciplinary research programs of these phenomena in order to have the scientific information needed to advance threat assessments appropriated to our conditions. It is also important that the authorities and people understand that, in part, the protection of the settlements of the lowland areas of accumulation, depending on management given to the upper reaches of the escarpment and transportation areas.

Spatially distributed pesticide exposure assessment in the Central Valley, California, USA

Energy Technology Data Exchange (ETDEWEB)

Luo Yuzhou [Department of Land, Air, and Water Resources, University of California, Davis, CA 95616 (United States); Zhang Minghua, E-mail: mhzhang@ucdavis.ed [Department of Land, Air, and Water Resources, University of California, Davis, CA 95616 (United States)

2010-05-15

Field runoff is an important transport mechanism by which pesticides move into the hydrologic environment of intensive agricultural regions such as California's Central Valley. This study presents a spatially explicit modeling approach to extend Pesticide Root Zone Model (PRZM), a field-scale pesticide transport model, into basin level. The approach was applied to simulate chlorpyrifos use in the Central Valley during 2003-2007. The average value of loading as percent of use (LAPU) is 0.031%. Results of this study provide strong evidence that surface runoff generation and pesticide application timing are the two influencing factors on the spatial and temporal variability of chlorpyrifos sources from agricultural fields. This is one of the first studies in coupling GIS and field-scale models and providing simulations for the dynamics of pesticides over an agriculturally dominated landscape. The demonstrated modeling approach may be useful for implementations of best management practice (BMP) and total maximum daily load (TMDL). - Runoff generation and application timing are governing factors on spatiotemporal variability of pesticide sources.

Spatially distributed pesticide exposure assessment in the Central Valley, California, USA

International Nuclear Information System (INIS)

Luo Yuzhou; Zhang Minghua

2010-01-01

Field runoff is an important transport mechanism by which pesticides move into the hydrologic environment of intensive agricultural regions such as California's Central Valley. This study presents a spatially explicit modeling approach to extend Pesticide Root Zone Model (PRZM), a field-scale pesticide transport model, into basin level. The approach was applied to simulate chlorpyrifos use in the Central Valley during 2003-2007. The average value of loading as percent of use (LAPU) is 0.031%. Results of this study provide strong evidence that surface runoff generation and pesticide application timing are the two influencing factors on the spatial and temporal variability of chlorpyrifos sources from agricultural fields. This is one of the first studies in coupling GIS and field-scale models and providing simulations for the dynamics of pesticides over an agriculturally dominated landscape. The demonstrated modeling approach may be useful for implementations of best management practice (BMP) and total maximum daily load (TMDL). - Runoff generation and application timing are governing factors on spatiotemporal variability of pesticide sources.

Upper critical field measurements in high-Tc superconducting oxides

Science.gov (United States)

Ousset, J. C.; Bobo, J. F.; Ulmet, J. P.; Rakoto, H.; Cheggour, N.

We present upper critical field measurements on the superconducting oxides RE Ba2Cu3O7-δ (RE = Y, Gd) performed in a pulsed magnetic field up to 43 T. Values for Hc2 as high as 52 T and 77 T for Y and Gd respectively, are expected at 77 K. However, in order to observe no resistive behaviour up to 43 T the temperature must be decreased down to 50 K. In the case of oxygen deficient systems the magnetoresistance reveals two superconducting phases wich could be related to two different orders of oxygen vacancies. Nous présentons des mesures de champ critique Hc2 sur les supraconducteurs TR Ba 2Cu3O7-δ (TR = Y, Gd) réalisées en champ magnétique pulsé jusqu'à 43 T. Elles permettent de prévoir des valeurs de H c2 de 52 T et 77 T respectivement pour Y et Gd à 77 K. Cependant, pour ne pas observer de comportement résistif jusqu'au champ maximum, il est nécessaire de refroidir l'échantillon jusqu'à 50 K. Dans le cas des systèmes déficients en oxygène (δ important) nous mettons en évidence l'existence de deux phases supraconductrices qui pourraient être dues à deux ordres différents des lacunes d'oxygène.

Spin filling of valley-orbit states in a silicon quantum dot

Energy Technology Data Exchange (ETDEWEB)

Lim, W H; Yang, C H; Zwanenburg, F A; Dzurak, A S, E-mail: wee.lim@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052 (Australia)

2011-08-19

We report the demonstration of a low-disorder silicon metal-oxide-semiconductor (Si MOS) quantum dot containing a tunable number of electrons from zero to N = 27. The observed evolution of addition energies with parallel magnetic field reveals the spin filling of electrons into valley-orbit states. We find a splitting of 0.10 meV between the ground and first excited states, consistent with theory and placing a lower bound on the valley splitting. Our results provide optimism for the realisation in the near future of spin qubits based on silicon quantum dots.

Many-body effects in valleytronics: direct measurement of valley lifetimes in single-layer MoS2.

Science.gov (United States)

Mai, Cong; Barrette, Andrew; Yu, Yifei; Semenov, Yuriy G; Kim, Ki Wook; Cao, Linyou; Gundogdu, Kenan

2014-01-08

Single layer MoS2 is an ideal material for the emerging field of "valleytronics" in which charge carrier momentum can be finely controlled by optical excitation. This system is also known to exhibit strong many-body interactions as observed by tightly bound excitons and trions. Here we report direct measurements of valley relaxation dynamics in single layer MoS2, by using ultrafast transient absorption spectroscopy. Our results show that strong Coulomb interactions significantly impact valley population dynamics. Initial excitation by circularly polarized light creates electron-hole pairs within the K-valley. These excitons coherently couple to dark intervalley excitonic states, which facilitate fast electron valley depolarization. Hole valley relaxation is delayed up to about 10 ps due to nondegeneracy of the valence band spin states. Intervalley biexciton formation reveals the hole valley relaxation dynamics. We observe that biexcitons form with more than an order of magnitude larger binding energy compared to conventional semiconductors. These measurements provide significant insight into valley specific processes in 2D semiconductors. Hence they could be used to suggest routes to design semiconducting materials that enable control of valley polarization.

Analysis of Mining-induced Valley Closure Movements

Science.gov (United States)

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

2016-05-01

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

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

Science.gov (United States)

Quade, Jay

1986-11-01

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

Fort Valley's early scientists: A legacy of distinction

Science.gov (United States)

Andrew J. Sanchez Meador; Susan D. Olberding

2008-01-01

When the Riordan brothers of Flagstaff, Arizona, asked Gifford Pinchot to determine why there was a deficit in ponderosa pine seedlings, neither party understood the historical significance of what they were setting in motion for the field of forest research. The direct result of that professional favor was the establishment of the Fort Valley Experiment Station (Fort...

NNSS Soils Monitoring: Plutonium Valley (CAU 366) FY2016

Energy Technology Data Exchange (ETDEWEB)

Nikolich, George [Desert Research Inst. (DRI), Las Vegas, NV (United States); Mizell, Steve [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg [Desert Research Inst. (DRI), Las Vegas, NV (United States); Campbell, Scott [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

2017-10-01

Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil transport from the Plutonium Valley Contamination Area (CA) as a result of wind transport and storm runoff in support of National Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the contamination areas. The DRI work is intended to confirm the likely mechanism(s) of transport and determine the meteorological conditions that might cause movement of contaminated soils. The emphasis of the work is on collecting sediment transported by channelized storm runoff at the Plutonium Valley investigation sites. These data will inform closure plans that are being developed, which will facilitate the appropriate closure design and post-closure monitoring.

Gravity field separation and mapping of buried quaternary valleys in Lolland, Denmark using old geophysical data

DEFF Research Database (Denmark)

Møller, M.J.; Olsen, Henrik; Ploug, C.

2007-01-01

In this paper we utilise the old industrial data for planning new surveys. The overall purpose is a detailed mapping of possible aquifers for the island of Lolland, Denmark. This is done through detection and modelling of the buried quaternary valleys, which either can serve as potential aquifers...... or potential aquifer barriers. The present paper deals only with one aspect of a larger study; namely a case story leading to the detection of unknown buried valleys and the first attempts to model them in 3D from gravity and seismics. Also, the emphasis here is not on any theoretical or even methodological...

Numerical Simulations of an Inversion Fog Event in the Salt Lake Valley during the MATERHORN-Fog Field Campaign

Science.gov (United States)

Chachere, Catherine N.; Pu, Zhaoxia

2018-01-01

An advanced research version of the Weather Research and Forecasting (WRF) Model is employed to simulate a wintertime inversion fog event in the Salt Lake Valley during the Mountain Terrain Atmospheric Modeling and Observations Program (MATERHORN) field campaign during January 2015. Simulation results are compared to observations obtained from the field program. The sensitivity of numerical simulations to available cloud microphysical (CM), planetary boundary layer (PBL), radiation, and land surface models (LSMs) is evaluated. The influence of differing visibility algorithms and initialization times on simulation results is also examined. Results indicate that the numerical simulations of the fog event are sensitive to the choice of CM, PBL, radiation, and LSM as well as the visibility algorithm and initialization time. Although the majority of experiments accurately captured the synoptic setup environment, errors were found in most experiments within the boundary layer, specifically a 3° warm bias in simulated surface temperatures compared to observations. Accurate representation of surface and boundary layer variables are vital in correctly predicting fog in the numerical model.

Crustal Deformation across the Jericho Valley Section of the Dead Sea Fault as Resolved by Detailed Field and Geodetic Observations

Science.gov (United States)

Hamiel, Yariv; Piatibratova, Oksana; Mizrahi, Yaakov; Nahmias, Yoav; Sagy, Amir

2018-04-01

Detailed field and geodetic observations of crustal deformation across the Jericho Fault section of the Dead Sea Fault are presented. New field observations reveal several slip episodes that rupture the surface, consist with strike slip and extensional deformation along a fault zone width of about 200 m. Using dense Global Positioning System measurements, we obtain the velocities of new stations across the fault. We find that this section is locked for strike-slip motion with a locking depth of 16.6 ± 7.8 km and a slip rate of 4.8 ± 0.7 mm/year. The Global Positioning System measurements also indicate asymmetrical extension at shallow depths of the Jericho Fault section, between 0.3 and 3 km. Finally, our results suggest the vast majority of the sinistral slip along the Dead Sea Fault in southern Jorden Valley is accommodated by the Jericho Fault section.

Analysis of exploratory wells in the Cerro Prieto Field and the Mexicali Valley

Energy Technology Data Exchange (ETDEWEB)

Cobo R., J.M.; Bermejo M., F.J.

1982-08-10

Agricultural development in the Mexicali Valley and in the high cost of electric power required to operate the irrigation wells in the Valley prompted the Mexican government to investigate the possibility of taking advantage of thermal manifestations in the area located 28 km southeast of the city of Mexicali to generate electric power and thereby partially decrease the flight of foreign exchange. In 1958, a geologic study of the southern and southeastern zone of Mexicali was conducted to identify the possibilities of tapping geothermal resources. The purpose of this study was to gain knowledge of the geologic conditions in this area and, if possible, to establish the location of exploratory and production wells and, on the basis of the results of the former, examine the geologic history in order to gain knowledge and understanding of the structural control of the steam. On the basis of this study, it was recommended that 3 exploratory wells should be drilled in order to locate weak zones that would easily allow for steam flow.

Valley- and spin-polarized oscillatory magneto-optical absorption in monolayer MoS2 quantum rings

Science.gov (United States)

Oliveira, D.; Villegas-Lelovsky, L.; Soler, M. A. G.; Qu, Fanyao

2018-03-01

Besides optical valley selectivity, strong spin-orbit interaction along with Berry curvature effects also leads to unconventional valley- and spin-polarized Landau levels in monolayer transition metal dichalcogenides (TMDCs) under a perpendicular magnetic field. We find that these unique properties are inherited to the magneto-optical absorption spectrum of the TMDC quantum rings (QRs). In addition, it is robust against variation of the magnetic flux and of the QR geometry. In stark contrast to the monolayer bulk material, the MoS2 QRs manifest themselves in both the optical valley selectivity and unprecedented size tunability of the frequency of the light absorbed. We also find that when the magnetic field setup is changed, the phase transition from Aharonov-Bohm (AB) quantum interference to aperiodic oscillation of magneto-optical absorption spectrum takes place. The exciton spectrum in a realistic finite thickness MoS2 QR is also discussed.

QUALITY WATER BALANCE AS A BASE FOR WETLANDS RESTORATION IN THE UPPER BIEBRZA VALLEY

Directory of Open Access Journals (Sweden)

Piotr Banaszuk

2016-06-01

Full Text Available Main goal of presented research was the assessment of the influence of water damming in existing land reclamation systems on the surface water quality of the Upper Biebrza River catchment. Surface water quality was assessed on the concentration of BOD5, total phosphorus (TP and total nitrogen (TN recorded in 2014 at several monitoring points along Biebrza River and its tributaries. The upper Biebrza R. has a little (at the Sztabin gauging point even an insufficient absorption capacity of organic pollutants and a high capacity for self-purifying and absorbing of TP and TN. The phosphorus binding capacity decreases along the river and in its upper reach it is necessary to reduce the load of P by 20% to maintain the river quality objectives. Water quality monitoring data and information about pollution sources showed high absorption capacities of TN in the monitored tributaries, which can receive an additional flux of this constituent in the amount exceeding the actual load up to several times. The absorption capacity of BOD5 and TP is lower by an order of magnitude. For Kropiwna R., it is required to reduce the load of organic components (measured as BOD5, which exceeds the requirements for the 1st quality class.

A New Velocity Field from a Dense GPS Array in the Southernmost Longitudinal Valley, Southeastern Taiwan

Directory of Open Access Journals (Sweden)

Horng-Yue Chen

2013-01-01

Full Text Available In the southernmost Longitudinal Valley (LV, Taiwan, we analyzed a dense GPS array composed of 10 continuous stations and 86 campaign-mode stations. By removing the effects of the four major earthquakes (one regional and three local occurred during the 1992 - 2010 observation period, we derived a new horizontal velocity field in this area, which then allows better locating the surface traces of the major active faults, including the Longitudinal Valley Fault (LVF system and the Central Range Fault, and characterizing the slip behaviors along the faults. Note that LVF reveals two sub-parallel strands in the study area: the Luyeh Fault to the west and the Lichi Fault to the east. Based on the results of strain analyses, including dilatation and shear strain, and projected vectors of station velocities across the major faults, we came to the following geological interpretations. During the inter-seismic periods, the surface deformation of the southernmost LV is mainly accommodated by the faulting on the two branches of the LVF; there is very little surface deformation on the Central Range Fault. The Luyeh River appears to act as a boundary to divide the LVF to behave differently to its northern and southern sides. The Lichi Fault reveals a change of slip kinematics from an oblique shearing/thrusting in the north to a nearly pure shearing with minor extension to the south. Regarding the slip behavior of the Luyeh Fault, it exhibits a creeping behavior in the north and a partially near-surface-locked faulting behavior in the south. We interpret that the two strands of the LVF merge together in the northern Taitung alluvial plain and turns to E-W trend toward the offshore area.

Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2

Science.gov (United States)

Tahir, M.; Krstajić, P. M.; Vasilopoulos, P.

2017-06-01

The recent experimental realization of high-quality WSe2 leads to the possibility of an efficient manipulation of its spin and valley degrees of freedom. Its electronic properties comprise a huge spin-orbit coupling, a direct band gap, and a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We evaluate its band structure and study ballistic electron transport through single and double junctions (or barriers) on monolayer WSe2 in the presence of spin Ms and valley Mv Zeeman fields and of an electric potential U . The conductance versus the field Ms or Mv decreases in a fluctuating manner. For a single junction, the spin Ps and valley Pv polarizations rise with M =Mv=2 Ms , reach a value of more than 55 % , and become perfect above U ≈45 meV while for a double junction this change can occur for U ≥50 meV and M ≥5 meV. In certain regions of the (M ,U ) plane Pv becomes perfect. The conductance gc, its spin-up and spin-down components, and both polarizations oscillate with the barrier width d . The ability to isolate various carrier degrees of freedom in WSe2 may render it a promising candidate for new spintronic and valleytronic devices.

Early Holocene pecan, Carya illinoensis, in the Mississippi River Valley near Muscatine, Iowa

Science.gov (United States)

Bettis, E. Arthur; Baker, R.G.; Nations, B.K.; Benn, D.W.

1990-01-01

A fossil pecan, Carya illinoensis (Wang.) K. Koch, from floodplain sediments of the Mississippi River near Muscatine, Iowa, was accelerator-dated at 7280 ?? 120 yr B.P. This discovery indicates that pecan was at or near its present northern limit by that time. Carya pollen profiles from the Mississippi River Trench indicate that hickory pollen percentages were much higher in the valley than at upland locations during the early Holocene. Pecan, the hickory with the most restricted riparian habitat, is the likely candidate for producing these peaks in Carya pollen percentages. Therefore, pecan may have reached its northern limit as early as 10,300 yr B.P. Its abundance in Early Archaic archaeological sites and the co-occurrence of early Holocene Carya pollen peaks with the arrival of the Dalton artifact complex in the Upper Mississippi Valley suggest that humans may have played a role in the early dispersal of pecan. ?? 1990.

X-Ray Amorphous Phases in Antarctica Dry Valley Soils: Insight into Aqueous Alteration Processes on Mars?

Science.gov (United States)

Ming, D. W.; Morris, R. V.; Rampe, E. B.; Golden, D. C.; Quinn, J. E.

2015-01-01

The Chemistry and Mineralogy (CheMin) instrument onboard the Mars Curiosity rover has detected abundant amounts (approx. 25-30 weight percentage) of X-ray amorphous materials in a windblown deposit (Rocknest) and in a sedimentary mudstone (Cumberland and John Klein) in Gale crater, Mars. On Earth, X-ray amorphous components are common in soils and sediments, but usually not as abundant as detected in Gale crater. One hypothesis for the abundant X-ray amorphous materials on Mars is limited interaction of liquid water with surface materials, kinetically inhibiting maturation to more crystalline phases. The objective of this study was to characterize the chemistry and mineralogy of soils formed in the Antarctica Dry Valleys, one of the driest locations on Earth. Two soils were characterized from different elevations, including a low elevation, coastal, subxerous soil in Taylor Valley and a high elevation, ultraxerous soil in University Valley. A variety of techniques were used to characterize materials from each soil horizon, including Rietveld analysis of X-ray diffraction data. For Taylor Valley soil, the X-ray amorphous component ranged from about 4 weight percentage in the upper horizon to as high as 15 weight percentage in the lowest horizon just above the permafrost layer. Transmission electron microscopy indicated that the presence of short-range ordered (SRO) smectite was the most likely candidate for the X-ray amorphous materials in the Taylor Valley soils. The SRO smectite is likely an aqueous alteration product of mica inherited from granitic materials during glaciation of Taylor Valley. The drier University Valley soils had lower X-ray amorphous contents of about 5 weight percentage in the lowest horizon. The X-ray amorphous materials in University Valley are attributed to nanoparticles of TiO2 and possibly amorphous SiO2. The high abundance of X-ray amorphous materials in Taylor Valley is surprising for one of the driest places on Earth. These materials

Modelling the internal boundary layer over the lower fraser valley, British Columbia

Energy Technology Data Exchange (ETDEWEB)

Batchvarova, E. [National Inst. of Meteorology and Hydrology, Sofia (Bulgaria); Steyn, D. [Univ. of British Columbia, Dept. of Geography, Vancouver (Canada); Cai, X. [Univ. of Birmingham, School of Geography, Edgbaston (United Kingdom); Gryning, S.E. [Risoe National Lab., Roskilde (Denmark); Baldi, M. [Inst. for Atmospheric Physics, IFA-CNR, Rome (Italy)

1997-10-01

In this study we use the very extensive data-set on temporal and spatial structure of the internal boundary layer on the Lower Faser Valley, Canada, collected during the so-called Pacific `93 field campaign, to study the ability of the simple applied model by Gryning and Batchvarova (1996) and the CSU-RAMS meso-scale model summarised in Pielke et al. (1992) to describe the development and variability of the internal boundary layer depth during the course of a day. Given the complexity of topography, coastline and land-use in the Lower Fraser Valley region, both models perform remarkably well. The simple applied model performs extremely well, given its simplicity. It is clear that correct specification of spatially resolved surface sensible heat flux and wind field are crucial to the success of this model which can be operated at very fine spatial resolution. The 3D model performs extremely well, though it too must capture the local wind field correctly for complete success. Its limited horizontal resolution results in strongly smoothed internal boundary layer height fields. (LN)

Geophysical Surveys of the Hydrologic Basin Underlying Yosemite Valley, California.

Science.gov (United States)

Maher, E. L.; Shaw, K. A.; Carey, C.; Dunn, M. E.; Whitman, S.; Bourdeau, J.; Eckert, E.; Louie, J. N.; Stock, G. M.

2017-12-01

UNR students in an Applied Geophysics course conducted geophysical investigations in Yosemite Valley during the months of March and August 2017. The goal of the study is to understand better the depth to bedrock, the geometry of the bedrock basin, and the properties of stratigraphy- below the valley floor. Gutenberg and others published the only prior geophysical investigation in 1956, to constrain the depth to bedrock. We employed gravity, resistivity, and refraction microtremor(ReMi) methods to investigate the interface between valley fill and bedrock, as well as shallow contrasts. Resistivity and ReMi arrays along three north-south transects investigated the top 50-60m of the basin fill. Gravity results constrained by shallow measurements suggest a maximum depth of 1000 m to bedrock. ReMi and resistivity techniques identified shallow contrasts in shear velocity and electrical resistivity that yielded information about the location of the unconfined water table, the thickness of the soil zone, and spatial variation in shallow sediment composition. The upper several meters of sediment commonly showed shear velocities below 200 m/s, while biomass-rich areas and sandy river banks could be below 150 m/s. Vs30 values consistently increased towards the edge of the basin. The general pattern for resistivity profiles was a zone of relatively high resistivity, >100 ohm-m, in the top 4 meters, followed by one or more layers with decreased resistivity. According to gravity measurements, assuming either -0.5 g/cc or -0.7 g/cc density contrast between bedrock and basin sediments, a maximum depth to bedrock is found south of El Capitan at respectively, 1145 ± 215 m or 818 ± 150 m. Longitudinal basin geometry coincides with the basin depth geometry discussed by Gutenberg in 1956. Their results describe a "double camel" shape where the deepest points are near El Capitan and the Ahwahnee Hotel and is shallowest near Yosemite Falls, in a wider part of the valley. An August Deep

Reconstructing Northern Hemisphere upper-level fields during World War II

Energy Technology Data Exchange (ETDEWEB)

Broennimann, S. [Lunar and Planetary Laboratory, University of Arizona, PO Box 210092, Tucson, AZ 85721-0092 (United States); Luterbacher, J. [Institute of Geography, University of Bern, Bern (Switzerland); NCCR Climate, University of Bern, Bern (Switzerland)

2004-05-01

Monthly mean fields of temperature and geopotential height (GPH) from 700 to 100 hPa were statistically reconstructed for the extratropical Northern Hemisphere for the World War II period. The reconstruction was based on several hundred predictor variables, comprising temperature series from meteorological stations and gridded sea level pressure data (1939-1947) as well as a large amount of historical upper-air data (1939-1944). Statistical models were fitted in a calibration period (1948-1994) using the NCEP/NCAR Reanalysis data set as predictand. The procedure consists of a weighting scheme, principal component analyses on both the predictor variables and the predictand fields and multiple regression models relating the two sets of principal component time series to each other. According to validation experiments, the reconstruction skill in the 1939-1944 period is excellent for GPH at all levels and good for temperature up to 500 hPa, but somewhat worse for 300 hPa temperature and clearly worse for 100 hPa temperature. Regionally, high predictive skill is found over the midlatitudes of Europe and North America, but a lower quality over Asia, the subtropics, and the Arctic. Moreover, the quality is considerably better in winter than in summer. In the 1945-1947 period, reconstructions are useful up to 300 hPa for GPH and, in winter, up to 500 hPa for temperature. The reconstructed fields are presented for selected months and analysed from a dynamical perspective. It is demonstrated that the reconstructions provide a useful tool for the analysis of large-scale circulation features as well as stratosphere-troposphere coupling in the late 1930s and early 1940s. (orig.)

Observations of Air Quality at the Edge of Kathmandu, Nepal, and the Diurnal Cycle of Air Pollution In and Around the Kathmandu Valley

Science.gov (United States)

Panday, A. K.; Prinn, R. G.; Regmi, R. P.

2006-12-01

The Kathmandu Valley is a bowl-shaped basin in the Nepal Himalaya, with a rapidly growing city surrounded by rice fields and steep terraced and forested mountain slopes. The valley's air quality is influenced by urban and rural emissions, nocturnal pooling of cold air, slope winds, and a daily exchange of air through mountain passes. To understand these processes and to inform air pollution policy in Nepal, we have carried out the most comprehensive study of air pollution in Nepal to date. During the 9-month dry season of 2004-2005, we carried out continuous measurements every minute of carbon monoxide, ozone, PM10, wind speed, wind direction, solar radiation, temperature, and humidity on the eastern edge of Kathmandu city, at a site that daily received air from both the city and rural areas. We recorded the diurnal cycle of the vertical temperature structure and stability with temperature loggers on towers and mountains. A sodar measured the mixed layer height and upper-level winds. 24-hour simultaneous bag sampling campaigns on mountain peaks, passes, the rural valley, and within the city provided glimpses of the spatial patterns of the diurnal cycle of CO -- a useful tracer of anthropogenic emissions. We measured winds on mountain passes and ozone on mountain peaks. At our main measurement site we found a daily-recurring pattern of CO and PM10, with an afternoon low showing rural background levels, even though the arriving air had traversed the city. This was followed by an evening peak starting at sunset, a second low late at night, and a morning peak enhanced by re-circulation. Pollutants emitted in the valley only traveled out of the valley between the late morning and sunset. During winter months, rush hour was outside of this period, enhancing the morning and evening peaks. Within the city, ozone dropped to zero at night. At mid-day we observed an ozone peak enhanced by photochemical production when the air mass that had been stagnant over the city swept

Surface slip during large Owens Valley earthquakes

KAUST Repository

Haddon, E. K.; Amos, C. B.; Zielke, Olaf; Jayko, A. S.; Burgmann, R.

2016-01-01

The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from approximate to 1.0 to 6.0 m and average 3.31.1 m (2 sigma). Vertical offsets are predominantly east-down between approximate to 0.1 and 2.4 m, with a mean of 0.80.5 m. The average lateral-to-vertical ratio compiled at specific sites is approximate to 6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.41.5 m, corresponding to a geologic M-w approximate to 7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.12.0 m, 12.8 +/- 1.5 m, and 16.6 +/- 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between approximate to 0.6 and 1.6 mm/yr (1 sigma) over the late Quaternary.

Surface slip during large Owens Valley earthquakes

Science.gov (United States)

Haddon, E.K.; Amos, C.B.; Zielke, O.; Jayko, Angela S.; Burgmann, R.

2016-01-01

The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from ∼1.0 to 6.0 m and average 3.3 ± 1.1 m (2σ). Vertical offsets are predominantly east-down between ∼0.1 and 2.4 m, with a mean of 0.8 ± 0.5 m. The average lateral-to-vertical ratio compiled at specific sites is ∼6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7–11 m and net average of 4.4 ± 1.5 m, corresponding to a geologic Mw ∼7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.1 ± 2.0 m, 12.8 ± 1.5 m, and 16.6 ± 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between ∼0.6 and 1.6 mm/yr (1σ) over the late Quaternary.

Surface slip during large Owens Valley earthquakes

KAUST Repository

Haddon, E. K.

2016-01-10

The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from approximate to 1.0 to 6.0 m and average 3.31.1 m (2 sigma). Vertical offsets are predominantly east-down between approximate to 0.1 and 2.4 m, with a mean of 0.80.5 m. The average lateral-to-vertical ratio compiled at specific sites is approximate to 6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.41.5 m, corresponding to a geologic M-w approximate to 7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.12.0 m, 12.8 +/- 1.5 m, and 16.6 +/- 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between approximate to 0.6 and 1.6 mm/yr (1 sigma) over the late Quaternary.

Topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface

Directory of Open Access Journals (Sweden)

Jiu-Jiu Chen

2017-11-01

Full Text Available The study for exotic topological effects of sound has attracted uprising interests in fundamental physics and practical applications. Based on the concept of valley pseudospin, we demonstrate the topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface, where a deterministic two-fold Dirac degeneracy is form by two plate modes. We show that the topological property can be controlled by the height of stubs deposited on the plate. By adjusting the relative heights of adjacent stubs, the valley vortex chirality and band inversion are induced, giving rise to a phononic analog of valley Hall phase transition. We further numerically demonstrate the valley states of plate-mode waves with robust topological protection. Our results provide a new route to design unconventional elastic topological insulators and will significantly broaden its practical application in the engineering field.

New Evidences for Early Paracas Textiles and Ceramics at Cerrillos, Ica Valley, Perú

OpenAIRE

Splitstoser, Jeffrey; Wallace, Dwight D.; Delgado, Mercedes

2012-01-01

Cerrillos is an Early to Middle Paracas civic-ceremonial site located in the upper Ica Valley of Perú. The site is known for its finely plastered adobe architecture, beautifully decorated ceramics, and complex textiles, many of which are decorated with camelid hair. Cerrillos was located in a strategically important place where the mountains meet the coastal desert and the Ica River bends south, a likely intersection in a road system that connected Cerrillos to contemporary sites in the Parac...

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

Science.gov (United States)

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

2009-11-01

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

A tracer investigation of the atmospheric dispersion in the Dyrnaes Valley, Greenland

International Nuclear Information System (INIS)

Gryning, S.-E.; Lyck, E.

1983-02-01

Mining at Kvanefjeld, Greenland, will result in releases of air pollution gases. In order to measure the dilution of these gases tracer experiments were carried out in July-August 1981. Results from these experiments are described. The Kvanefjeld constitutes the northwestern side of a valley. The tracer was released at the Kvanefjeld during the night and sampled in the valley. The measured tracer concentrations were compared with those calculated by use of a conventional model of the dispersion of plumes. The dilution of the tracer was found to correspond to the dilution at ground level of a plume from a stack of 100-200 m height in atmospheric neutral conditions (wind speed 5 m/s). General aspects of the flow-field in the valley are discussed. It was observed that the flow direction in the valley shifts between downvalley and upvalley with a period of approximately 1 hour. It is suggested that this behaviour is caused by the interplay of a drainage flow and a sea-breeze. (author)

Detection of neotectonic deformations along the Rio do Peixe Valley, Western São Paulo State, Brazil, based on the distribution of late Quaternary allounits

Directory of Open Access Journals (Sweden)

Mario Lincoln Etchebehere

2005-11-01

Full Text Available Terrace deposits (34 10 ka were mapped in the Rio do Peixe valley and submitted to an allostratigraphic analysis. Three allomembers (viz. “A”, “B”, and “C” were established in the medium to lower river valley and other three allounits (allomembers “ L”, “M” and “N” were defined in the upper valley. It is probable tha “B” and “M” allomembers represent the same stratigraphic level. The spatial distribution of these allomember shows the influence of the Recent base-level changes, due to neotectonics events. Longitudinal cross-section o the Rio do Peixe valley shows that it is possible to define some areas with differential tectonic movements, tha includes uplift blocks (prone to erosion and terrace deposit destruction, and other areas with relative subsidence, controlling both the Recent alluvial plains and the preservation of some ancient terrace deposits. This scenery is in accordance with regional tectonic studies.

Daytime wind valleys adjacent to the Great Salt Lake

Energy Technology Data Exchange (ETDEWEB)

Stone, G.L. (Los Alamos National Lab., NM (USA)); Hoard, D.E. (Amparo Corp., Santa Fe, NM (USA))

1990-01-01

In 1986 Los Alamos National Laboratory was engaged by the US Army to study the meteorological aspects of emergency preparedness at several sites where toxic materials are stored and handled. The project included a series of tracer and meteorological field experiments in the vicinity of the Tooele Army Depot. These experiments generated a large data set for validating numerical simulations and for empirical analyses of the local meteorology. This paper discusses the main characteristics of the daytime, up-valley flow at the Utah site, including frequency of occurrence, horizontal and vertical structure, and temporal evolution. Some parameters controlling the variability in onset time for up-valley flow are identified, and an empirical forecasting scheme is discussed. 16 refs., 7 figs.

Providing an Authentic Research Experience for University of the Fraser Valley Undergraduate Students by Investigating and Documenting Seasonal and Longterm Changes in Fraser Valley Stream Water Chemistry.

Science.gov (United States)

Gillies, S. L.; Marsh, S. J.; Peucker-Ehrenbrink, B.; Janmaat, A.; Bourdages, M.; Paulson, D.; Groeneweg, A.; Bogaerts, P.; Robertson, K.; Clemence, E.; Smith, S.; Yakemchuk, A.; Faber, A.

2017-12-01

Undergraduate students in the Geography and Biology Departments at the University of the Fraser Valley (UFV) have been provided the opportunity to participate in the time series sampling of the Fraser River at Fort Langley and Fraser Valley tributaries as part of the Global Rivers Observatory (GRO, www.globalrivers.org) which is coordinated by Woods Hole Oceanographic Institution and Woods Hole Research Center. Student research has focussed on Clayburn, Willband and Stoney Creeks that flow from Sumas Mountain northwards to the Fraser River. These watercourses are increasingly being impacted by anthropogenic activity including residential developments, industrial activity, and agricultural landuse. Students are instructed in field sampling protocols and the collection of water chemistry data and the care and maintenance of the field equipment. Students develop their own research projects and work in support of each other as teams in the field to collect the data and water samples. Students present their findings as research posters at local academic conferences and at UFV's Student Research Day. Through their involvement in our field research our students have become more aware of the state of our local streams, the methods used to monitor water chemistry and how water chemistry varies seasonally.

Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado

Science.gov (United States)

Ball, Lyndsay B.; Bloss, Benjamin R.; Bedrosian, Paul A.; Grauch, V.J.S.; Smith, Bruce D.

2015-01-01

In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field information over matching areas. These data were collected to provide insight into the distribution of groundwater brine in the Paradox Valley, the extent of clay aquitards in the San Luis Valley, and to improve our understanding of the geologic framework for both regions. This report describes these contracted surveys and releases digital data supplied under contract to the USGS.

Husbandry, working practices and field performance when using draught oxen in land preparation in Shambat, Nile Valley, Sudan.

Science.gov (United States)

Makki, Elsamawal Khalil

2014-01-01

Little quantitative information is available on animal power in the Nile Valley in Sudan, despite that it is being used in the area for centuries and playing an important role in agriculture in the present day. A survey was conducted to assess draught oxen management and its association with field capacity and efficiency at the farm level and to identify potential areas for intervention. A sample of 50 farmers was selected for this purpose using the systematic random sampling technique. The main management parameters discussed were animal health, feeding, housing, work strategy and care for yoke and plough. The results showed that most of the farmers poorly manage their animals, and this was reflected in low working speeds and field efficiencies. The main dimensions of poor management were in veterinary care (78 % did not take their animals to the veterinary centre), feeding (66 % feed their animals shortly before work) and care for yoke (80 % did not follow daily care measures for their yokes) and plough (74 % did not follow plough care measure before and after work). Low working speeds (0.90–2.0 km/h) were recorded by the majority of the farmers (64 %). The majority of the farmers (70 %) recorded field capacities between 0.06 and 0.10 ha/h, while all of them worked at high field efficiencies of >86 %. The only parameter that significantly affected field capacity was the yoke-related wounds (p = 0.019). Extension advice and capacity building in husbandry and working practices were identified as principal entry points for intervention.

Legacy lead arsenate soil contamination at childcare centers in the Yakima Valley, Central Washington, USA.

Science.gov (United States)

Durkee, Jenna; Bartrem, Casey; Möller, Gregory

2017-02-01

From the early 1900s to the 1950s, Yakima Valley orchards were commonly treated with lead arsenate (LA) insecticides. Lead (Pb) and arsenic (As) soil contamination has been identified on former orchard lands throughout Central Washington and pose a threat to human health and the environment. The levels of Pb and As in soil and interior dust at participating childcare centers in the Upper Yakima Valley (Yakima County), Washington were sampled to explore exposure potential for young children. Childcare center soils were collected from two soil depths, homogenized, and analyzed in bulk by a field-portable X-ray fluorescence spectrometer (XRF). Interior dust wipes samples were collected from at least two locations in each facility. All soil samples >250 mg/kg Pb and/or >20 As mg/kg were sieved to 250 μm, tested by XRF a second time, and analyzed via acid digestion and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Bulk and sieved XRF results, as well as ICP-MS to XRF results were strongly correlated. Maximum Pb and As XRF results indicated that 4 (21%) and 8 (42%) of the 19 childcare centers surveyed exceeded the regulatory standard for Pb and As, respectively. Historic land use was significantly associated with elevated Pb and As levels. Interior dust loadings were below United States Environmental Protection Agency (EPA) guidelines. Childcare centers are areas of intensive use for children and when coupled with potential residential exposure in their homes, the total daily exposure is a potential hazard to children. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2014-01-01

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

Small martian valleys: Pristine and degraded morphology

International Nuclear Information System (INIS)

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

1986-01-01

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

Resource assessment of the Imperial Valley. Final report

Energy Technology Data Exchange (ETDEWEB)

Biehler, S.; Lee, T.

1977-01-01

A resource assessment of the Imperial Valley has been made based on the use of the gravity anomalies as indicators of total excess mass. These data indicate a potential of producing electric power of 7 to 80 thousand megawatts for 30 years. Over half of the total potential is located in the Salton Sea Anomaly and approximately half of the potential of the Salton Sea field is water covered. An attempt has been made to assess not only the heat in storage in the fluid but also recoverable from the country rock by reinjection. Based on calculations, the natural recharge rate of heat in the Valley due to sea floor spreading is too small to give the resource an indefinite life-span since the economic rates of withdrawal appear to be at least an order of magnitude greater.

[Effects of grazing disturbance on soil active organic carbon in mountain forest-arid valley ecotone in the upper reaches of Minjiang River].

Science.gov (United States)

Liu, Shan-Shan; Zhang, Xing-Hua; Gong, Yuan-Bo; Li, Yuan; Wang, Yan; Yin, Yan-Jie; Ma, Jin-Song; Guo, Ting

2014-02-01

Effects of grazing disturbance on the soil carbon contents and active components in the four vegetations, i.e., artificial Robinia pseudoacacia plantation, artificial poplar plantation, Berberis aggregate shrubland and grassland, were studied in the mountain forest-arid valley ecotone in the upper Minjiang River. Soil organic carbon and active component contents in 0-10 cm soil layer were greater than in 10-20 cm soil layer at each level of grazing disturbance. With increasing the grazing intensity, the total organic carbon (TOC), light fraction organic carbon (LFOC), particulate organic carbon (POC) and easily oxidized carbon (LOC) contents in 0-10 cm soil layer decreased gradually in the artificial R. pseudoacacia plantation. The LFOC content decreased, the POC content increased, and the TOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the artificial poplar plantation. The POC content decreased, and the TOC, LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the B. aggregate shrubland. The POC and TOC contents decreased, and the LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the grassland. The decreasing ranges of LOC, LFOC and POC contents were 0.1-7.9 times more than that of TOC content. There were significant positive relationships between TOC and LOC, LFOC and POC, suggesting that the active organic carbon components could reflect the change of soil total carbon content.

Estimating the unknown components of nutrient mass balances for forestry plantations in mine rehabilitation, upper Hunter Valley, New South Wales, Australia.

Science.gov (United States)

Mercuri, A M; Duggin, J A; Daniel, H; Lockwood, P V; Grant, C D

2006-04-01

Commercial forestry plantations as a postmining land use in the Upper Hunter Valley of New South Wales, Australia are restricted by both the poor nutrient availability of mining substrates and low regional rainfall. An experiment was conducted to investigate whether municipal waste products and saline groundwater from coal mining operations could improve early tree growth without impacting on the environment through salt accumulation and/or nutrient enrichment and changes in groundwater quality. Potential impacts were investigated by quantifying the nutrient cycling dynamics within the plantation using an input-output mass balance approach for exchangeable calcium (Ca(2+)), exchangeable magnesium (Mg(2+)), exchangeable potassium (K(+)), exchangeable sodium (Na(+)), nitrogen (N), and phosphorus (P). Measured inputs to and outputs from the available nutrient pool in the 0-30 cm of the overburden subsystem were used to estimate the net effect of unmeasured inputs and outputs (termed "residuals"). Residual values in the mass balance of the irrigated treatments demonstrated large leaching losses of exchangeable Ca, Mg, K, and Na. Between 96% and 103% of Na applied in saline mine-water irrigation was leached below the 0-30-cm soil profile zone. The fate of these salts beyond 30 cm is unknown, but results suggest that irrigation with saline mine water had minimal impact on the substrate to 30 cm over the first 2 years since plantation establishment. Accumulations of N and P were detected for the substrate amendments, suggesting that organic amendments (particularly compost) retained the applied nutrients with very little associated losses, particularly through leaching.

Valley dependent transport in graphene L junction

Science.gov (United States)

Chan, K. S.

2018-05-01

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

Early Holocene pecan, Carya illinoensis, in the Mississippi River Valley near Muscatine, Iowa*1

Science.gov (United States)

Bettis, E. Arthur; Baker, Richard G.; Nations, Brenda K.; Benn, David W.

1990-01-01

A fossil pecan, Carya illinoensis (Wang.) K. Koch, from floodplain sediments of the Mississippi River near Muscatine, Iowa, was accelerator-dated at 7280 ± 120 yr B.P. This discovery indicates that pecan was at or near its present northern limit by that time. Carya pollen profiles from the Mississippi River Trench indicate that hickory pollen percentages were much higher in the valley than at upland locations during the early Holocene. Pecan, the hickory with the most restricted riparian habitat, is the likely candidate for producing these peaks in Carya pollen percentages. Therefore, pecan may have reached its northern limit as early as 10,300 yr B.P. Its abundance in Early Archaic archaeological sites and the co-occurrence of early Holocene Carya pollen peaks with the arrival of the Dalton artifact complex in the Upper Mississippi Valley suggest that humans may have played a role in the early dispersal of pecan.

The Silicon Valley Eco System. High-energetic in many ways; Het Silicon Valley Eco Systeem: hoogenergetisch in vele opzichten

Energy Technology Data Exchange (ETDEWEB)

Van den Heuvel, J.

2012-04-15

The highly commended Silicon Valley Eco System is bubbling with energy with regard to the subjects that are focused upon, including sustainable energy, or the widely available expertise that is needed for the developments, good ideas, capital and optimism, fed by frequent examples of extraordinarily successful companies. The sheer endlessness of network opportunities joins all these elements frequently. This article addresses several noteworthy interactions in the field of sustainable energy over the last period. [Dutch] Het veel geroemde Silicon Valley eco systeem bruist van energie in de vorm van de onderwerpen waar men zich op richt, waaronder duurzame energie, of de ruim aanwezige expertise die nodig is voor de ontwikkelingen, goede ideeen, kapitaal, en optimisme, gevoed door regelmatige voorbeelden van buitensporig succesvolle bedrijven. De schier oneindige netwerkmogelijkheden brengen al deze elementen met grote regelmaat bij elkaar. In dit artikel volgen enkele vermeldenswaardige interacties op het vlak van duurzame energie uit de afgelopen periode.

Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

KAUST Repository

Tahir, M.

2013-04-26

We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

KAUST Repository

Tahir, M.; Manchon, Aurelien; Sabeeh, K.; Schwingenschlö gl, Udo

2013-01-01

We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

In-situ reconstruction of the MSRs at the Beaver Valley Nuclear Power Station

International Nuclear Information System (INIS)

Deahna, S.T.; Yarden, A.L.; Tam, C.W.

1992-01-01

Moisture Separator Reheaters (MSRs) have been problem components at Beaver Valley Unit 1 since the initial plant start-up in 1976. Their performance had been ineffective and reheater tube reliability was becoming a limiting factor in MSR operation. Many of the problems encountered were common to the nuclear industry. In 1991, Duquesne Light performed a major overhaul of the Beaver Valley Unit 1 MSRs in an attempt to restore them to an acceptable level of performance. This paper summarizes the operating history, engineering redesign, field reconstruction, and subsequent performance of these MSRs

Ground-water quality in the southeastern Sacramento Valley aquifer, California, 1996

Science.gov (United States)

Milby Dawson, Barbara J.

2001-01-01

In 1996, the U.S. Geological Survey sampled 29 domestic wells and 2 monitoring wells in the southeastern Sacramento Valley as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. This area, designated as the NAWQA Sacramento subunit study area, was chosen because it had the largest amount of ground-water use in the Sacramento River Basin. The Sacramento subunit study area is about 4,400 square kilometers and includes intense agricultural and urban development. The wells sampled ranged from 14.9 to 79.2 meters deep. Ground-water samples from 31 wells were analyzed for 6 field measurements, 14 inorganic constituents, 6 nutrient constituents, organic carbon, 86 pesticides, 87 volatile organic compounds, tritium (hydrogen-3), radon-222, deuterium (hydrogen-2), and oxygen-18. Nitrate levels were lower than the 2000 drinking-water standards in all but one well, but many detections were in the range that indicated an effect by human activities on ground-water quality. Radon was detected in all wells, and was measured at levels above the proposed Federal 2000 maximum contaminant level in 90 percent of the wells. Five pesticides and one pesticide degradation product were detected in ground-water samples and concentrations were below 2000 drinking-water standards. All pesticides detected during this study have been used in the Sacramento Valley. Thirteen volatile organic compounds were detected in ground water. One detection of trichloroethene was above Federal 2000 drinking-water standards, and another, tetrachloromethane, was above California 1997 drinking-water standards; both occurred in a well that had eight volatile organic compound detections and is near a known source of ground-water contamination. Pesticides and volatile organic compounds were detected in agricultural and urban areas; both pesticides and volatile organic compounds were detected at a higher frequency in urban wells. Ground-water chemistry indicates that natural

Origin, Extent, and Thickness of Quaternary Geologic Units in the Willamette Valley, Oregon

Science.gov (United States)

O'Connor, Jim E.; Sarna-Wojcicki, Andrei M.; Wozniak, Karl C.; Polette, Danial J.; Fleck, Robert J.

2001-01-01

Stratigraphic and chronologic information collected for Quaternary deposits in the Willamette Valley, Oregon, provides a revised stratigraphic framework that serves as a basis for a 1:250,000-scale map, as well as for thickness estimates of widespread Quaternary geologic units. We have mapped 11 separate Quaternary units that are differentiated on the basis of stratigraphic, topographic, pedogenic, and hydrogeologic properties. In summation, these units reflect four distinct episodes in the Quaternary geologic development of the Willamette Valley: 1) Fluvial sands and gravels that underlie terraces flanking lowland margins and tributary valleys were probably deposited between 2.5 and 0.5 million years ago. They are the oldest widespread surficial Quaternary deposits in the valley. Their present positions and preservation are undoubtedly due to postdepositional tectonic deformation - either by direct tectonic uplift of valley margins, or by regional tectonic controls on local base level. 2) Tertiary and Quaternary excavation or tectonic lowering of the Willamette Valley accommodated as much as 500 m (meters) of lacustrine and fluvial fill. Beneath the lowland floor, much of the upper 10 to 50 m of fill is Quaternary sand and gravel deposited by braided channel systems in subhorizontal sheets 2 to 10 m thick. These deposits grade to gravel fans 40 to 100 m thick where major Cascade Range rivers enter the valley and are traced farther upstream as much thinner valley trains of coarse gravel. The sand and gravel deposits have ages that range from greater than 420,000 to about 12,000 years old. A widely distributed layer of sand and gravel deposited at about 12 ka (kiloannum, thousands of years before the present) is looser and probably more permeable than older sand and gravel. Stratigraphic exposures and drillers' logs indicate that this late Pleistocene unit is mostly between 5 and 20 m thick where it has not been subsequently eroded by the Willamette River and its

Preliminary study on the flow field over Greece

International Nuclear Information System (INIS)

Pissimanis, D; Karras, G; Notaridou, V; Bartzis, J.G.

1989-02-01

Full text: For radiation risk assessment from long distance sources, the knowledge of the synoptic air flow field patterns over the territory under consideration is required. In the present study a first representation of the air flow field in the atmospheric boundary layer over Greece is attempted. For this purpose, synoptic weather maps at 850mb available for a ten-years period, as well as sounding data from six meteorological stations were utilized, while the Greek territory was divided into four parts, i.e. NW, NE, SW, SE, with a number of stations in each sector. It was shown that the prevailing wind directions of the upper flow are either of the W/SW sector (winter, spring) or the northern sector (summer, autumn). In the SE sector a stronger tendency towards winds from the nothern sector was shown, due to the thermal low near Cyprus. The main characteristics of the surface flow is the strong influence by topographical features. Typical examples are the strong NW winds in Northern Greece due to the Vardar Valley, and the sea breeze circulations at coastal environments. (author)

Preliminary appraisal of ground water in and near the ancestral Missouri River Valley, northeastern Montana

Science.gov (United States)

Levings, G.W.

1986-01-01

A preliminary appraisal was conducted in and near the ancestral Missouri River valley in northeastern Montana to describe the groundwater resources and to establish a data base for the area. The data base then could be used for future evaluation of possible changes in water levels or water quality. In this area, consolidated aquifers are the Upper Cretaceous Fox Hills-lower Hell Creek aquifer and the overlying Paleocene Fort Union Formation. Unconsolidated aquifers are Pleistocene terrace gravel and glacial deposits and Holocene alluvial deposits. Aquifers are recharged by precipitation, infiltration of streamflow, and possibly leakage from lakes and potholes. Groundwater moves from topographically higher areas to the ancestral valley, then along the ancestral valley to the southwest. Water is discharged from aquifers by evapotranspiration, springs and seeps, movement directly into streams and lakes, and from pumping wells. Average well yields are greatest for irrigation wells completed in outwash gravel (886 gallons/min). Eighteen wells were completed in various aquifers to monitor potential long-term changes in water levels and water quality. Measured water levels declined about 2 ft. or less during the study (1982-85). Chemical analysis of groundwater samples indicated that concentrations of some dissolved constituents exceeded U.S. Environmental Protection Agency standards for drinking water. (USGS)

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

Science.gov (United States)

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

2009-06-01

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

Topological Valley Transport in Two-dimensional Honeycomb Photonic Crystals.

Science.gov (United States)

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

2018-01-25

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

Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin

Science.gov (United States)

Godfrey, N.J.; Beaudoin, B.C.; Klemperer, S.L.; Levander, A.; Luetgert, J.; Meltzer, A.; Mooney, W.; Tréhu, A.

1997-01-01

The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great Valley ophiolite), which in turn is underlain by a westward extension of lower-density continental crust (Sierran affinity material). We used an integrated modeling philosophy, first modeling the seismic-refraction data to obtain a final velocity model, and then modeling the long-wavelength features of the gravity data to obtain a final density model that is constrained in the upper crust by our velocity model. The crustal section of Great Valley ophiolite is 7-8 km thick, and the Great Valley ophiolite relict oceanic Moho is at 11-16 km depth. The Great Valley ophiolite does not extend west beneath the Coast Ranges, but only as far as the western margin of the Great Valley, where the 5-7-km-thick Great Valley ophiolite mantle section dips west into the present-day mantle. There are 16-18 km of lower-density Sierran affinity material beneath the Great Valley ophiolite mantle section, such that a second, deeper, "present-day" continental Moho is at about 34 km depth. At mid-crustal depths, the boundary between the eastern extent of the Great Valley ophiolite and the western extent of Sierran affinity material is a near-vertical velocity and density discontinuity about 80 km east of the western margin of the Great Valley. Our model has important implications for crustal growth at the North American continental margin. We suggest that a thick ophiolite sequence was obducted onto continental material, probably during the Jurassic Nevadan orogeny, so that the Great Valley basement is oceanic crust above oceanic mantle vertically stacked above continental crust and continental mantle.

Fort Valley's early scientists: A legacy of distinction (P-53)

Science.gov (United States)

Andrew J. Sanchez Meador; Susan D. Olberding

2008-01-01

When the Riordan brothers of Flagstaff, Arizona asked Gifford Pinchot to determine why there was a deficit in ponderosa pine seedlings, neither party understood the historical significance of what they were setting in motion for the field of forest research. The direct result of that professional favor was the establishment of the Fort Valley Experiment Station (Fort...

Data-mining Based Detection of Glaciers: Quantifying the Extent of Alpine Valley Glaciation

Directory of Open Access Journals (Sweden)

Wei Luo

2015-07-01

Full Text Available The extent of glaciation in alpine valleys often gives clues to past climates, plate movement, mountain landforms, bedrock geology and more. However, without field investigation, the degree to which a valley was affected by a glacier has been difficult to assess. We developed a model that uses quantitative parameters derived from digital elevations model (DEM data to predict whether a glacier was likely present in an alpine valley. The model's inputs are mainly derived from the basin hypsometry, and a new parameter termed the Hypothetical Basin Equilibrium Elevation (HBEE, which is based on the equilibrium elevation altitude (ELA of a glacier. We used data mining techniques that comb through large data sets to find patterns for classification and prediction as the basis for the model. Four classifiers were utilized, and each was tested with two different training set/test data ratios of nearly 150 basins that were previously delineated as fully- or non-glaciated. The classifiers had a predictive accuracy of up to 90% with none falling below 72%. Two of the classifiers, classification tree and naïve-Bayes, have graphical outputs that visually describe the classification process, predictive results, and in the naïve-Bayes case, the relative effectiveness towards the model of each attribute. In all scenarios, the HBEE was found to be an accurate predictor for the model. The model can be applied to any area where glaciation may have occurred, but is particularly useful in areas where the valley is inaccessible for detailed field investigation.

Remote sensing techniques for monitoring the Rio Grande Valley cotton stalk destruction program

Energy Technology Data Exchange (ETDEWEB)

Richardson, A.J.; Gerbermann, A.H.; Summy, K.R.; Anderson, G.L. (Department of Agriculture, Weslaco, TX (United States))

1993-09-01

Post harvest cotton (Gossypium hirsutum L.) stalk destruction is a cultural practice used in the Rio Grande Valley to suppress over wintering populations of boll weevils (Anthonomus grandis Boheman) without using chemicals. Consistent application of this practice could substantially reduce insecticide usage, thereby minimizing environmental hazards and increasing cotton production profits. Satellite imagery registered within a geographic information system was used to monitor the cotton stalk destruction program in the Rio Grande Valley. We found that cotton stalk screening procedures based on standard multispectral classification techniques could not reliably distinguish cotton from sorghum. Greenness screening for cotton plant stalks after the stalk destruction deadline was possible only where ground observations locating cotton fields were available. These findings indicate that a successful cotton stalk destruction monitoring program will require satellite images and earth referenced data bases showing cotton field locations.

Vortices in nonuniform upper-hybrid field

International Nuclear Information System (INIS)

Davydova, T.A.; Vranjes, J.

1992-01-01

The equations describing the interaction of an upper-hybrid pump wave with small low-frequency density perturbations are discussed under assumption that the pump is spatially nonuniform. The conditions for the modulational instability are investigated. Instead of a dispersion relation, describing the growth of perturbations in the case of an uniform pump, in our case of nonuniform pump a differential equation is obtained and from its eigenvalues are found the instability criteria. Taking into account the slow-frequency self-interaction terms some localized solutions similar to dipole vortices are found, but described by analytic functions in all space. It is shown that their characteristic size and speed are determined by the pump intensity and its spatial structure. (au)

[Rift Valley fever: sporadic infection of French military personnel outside currently recognized epidemic zones].

Science.gov (United States)

Durand, J P; Richecoeur, L; Peyrefitte, C; Boutin, J P; Davoust, B; Zeller, H; Bouloy, M; Tolou, H

2002-01-01

For three years the arbovirus surveillance unit of the Tropical Medicine Institute of the French Army Medical Corps (French acronym IMTSSA) in Marseille, France has been investigating causes of benign non-malarial febrile syndromes in French military personnel serving outside mainland France. The methodology used in N'Djamena consisted of sending frozen specimens collected concomitant with viremia, to Marseille for culture. During the rainy season of 2001, specimens were collected from a total of 50 febrile soldiers. Cultures allowed isolation and identification of two strains of Rift Valley virus. The risk of contamination exists not only in the field but also in mainland hospital departments treating infected patients. Routine serological diagnosis for Rift Valley fever must be DISCUSSED for all patients in the field or returning from Africa.

Study on Change of Pipes Formed in the Upper Part of a Collapse in a Crystalline Schist Area and Response of Pipe Flow to Rain

OpenAIRE

平松, 晋也; 前川, 美紀子; 小山内, 信智; Shinya, HIRAMATSU; Mikiko, MAEKAWA; Nobutomo, OSANAI; 高知大学農学部; 高知大学農学部; 国土交通名四国山地砂防工事事務所; Faculty of Agriculture, Kochi University; Faculty of Agriculture, Kochi University; Shikoku Mountainous Region Sabo Work Office, Ministry of Land, Infrastructure and Transport

2002-01-01

Pipes formed by a small animal-activity, root decay and underground erosion exist frequently in the upper part of rain-induced collapse sites. These pipes affect significantly on water discharge and occurrences of hillside landslides in a watershed. Many hillside landslides occurred at Nishiiyayama village in Tokushima Prefecture, on June 29 th, 1999, due to heavy rainfall. In the upper part of C torrent of Tobinosu-valley, hillside landslides occurred, and several pipes appeared. Investigati...

The Brahmaputra River: a stratigraphic analysis of Holocene avulsion and fluvial valley reoccupation history

Science.gov (United States)

Hartzog, T. R.; Goodbred, S. L.

2011-12-01

The Brahmaputra River, one of the world's largest braided streams, is a major component of commerce, agriculture, and transportation in India and Bangladesh. Hence any significant change in course, morphology, or behavior would be likely to influence the regional culture and economy that relies on this major river system. The history of such changes is recorded in the stratigraphy deposited by the Brahmaputra River during the Holocene. Here we present stratigraphic analysis of sediment samples from the boring of 41 tube wells over a 120 km transect in the upper Bengal Basin of northern Bangladesh. The transect crosses both the modern fluvial valley and an abandoned fluvial valley about 60 km downstream of a major avulsion node. Although the modern Brahmaputra does not transport gravel, gravel strata are common below 20 m with fluvial sand deposits dominating most of the stratigraphy. Furthermore, the stratigraphy preserves very few floodplain mud strata below the modern floodplain mud cap. These preliminary findings will be assessed to determine their importance in defining past channel migration, avulsion frequency, and the reoccupation of abandoned fluvial valleys. Understanding the avulsion and valley reoccupation history of the Brahmaputra River is important to assess the risk involved with developing agriculture, business, and infrastructure on the banks of modern and abandoned channels. Based on the correlation of stratigraphy and digital surface elevation data, we hypothesize that the towns of Jamalpur and Sherpur in northern Bangladesh were once major ports on the Brahmaputra River even though they now lie on the banks of small underfit stream channels. If Jamalpur and Sherpur represent the outer extent of the Brahmaputra River braid-belt before the last major avulsion, these cities and any communities developed in the abandoned braid-belt assume a high risk of devastation if the next major avulsion reoccupies this fluvial valley. It is important to

Recent characterization activities of Midway Valley as a potential repository surface facility site

International Nuclear Information System (INIS)

Gibson, J.D.; Wesling, J.R.; Swan, F.H.; Bullard, T.F.

1992-01-01

Midway Valley, located at the eastern base of Yucca Mountain, Nye County, Nevada, has been identified as a possible location for the surface facilities of a potential high-level nuclear-waste repository. This structural and topographic valley is bounded by two north- trending, down-to-the-west normal faults: the Paintbrush Canyon fault on the east and the Bow Ridge fault on the west. Surface and near-surface geological data have been acquired from Midway Valley during the past three years with particular emphasis on evaluating the existence of Quaternary faults. A detailed (1:6000) surficial geological map has been prepared based on interpretation of new and existing aerial photographs, field mapping, soil pits, and trenches. No evidence was found that would indicate displacement of these surficial deposits along previously unrecognized faults. However, given the low rates of Quaternary faulting and the extensive areas that are covered by late Pleistocene to Holocene deposits south of Sever Wash, Quaternary faulting between known faults cannot be precluded based on surface evidence alone. Middle to late Pleistocene alluvial fan deposits (Unit Q3) exist at or near the surface throughout Midway Valley. Confidence is increased that the potential for surface fault rupture in Midway Valley can be assessed by excavations that expose the deposits and soils associated with Unit Q3 or older units (middle Pleistocene or earlier)

Vegetation dynamics of restored and remnant Willamette Valley, OR wet prairie wetlands

Science.gov (United States)

Wet prairie wetlands are now one of the rarest habitat types in the Willamette Valley of Oregon, USA. Less than two percent of their historic extent remains, with most having been converted into agricultural fields (Christy and Alverson 2011, ONHP 1983). This habitat is the obl...

Trial study on design of irradiated fields of radiotherapy in cervical and upper thoracic esophageal cancer

International Nuclear Information System (INIS)

Liu Hui; Zeng Zhifan; Cui Nianji; He Zhichun; Huang Shaomin

2006-01-01

Objective: To compare three kinds of irradiation treatment plans for cervical and upper thoracic esophageal cancer, in order to arrived at proper decision for the patient. Methods: From February 2001 to June 2004, 43 such patients were studied with three different simulated treatment plans made including conformal plan, conventional four-field plan and conventional two-field plan for every one. All plans were evaluated with iso- dose curve and dose-volume histogram. Results: GTV on 95% isodose curve was 99.5%, 98.2% and 87.4% in conformal plan, conventional four-field plan and conventional two-field plan, respectively; PTV 1 and PTV 2 on 95% isodose with 97.8%, 97.2%, 94.8% and 95.8%, 86.6%, 73.7%. The volume of > 20 Gy dose of left lung accepted was 18.6%, 17.2% and 32.3%, in conformal plan, conventional four-field plan and conventional two-field plan, respectively; the right lung received 20.5% ,19.9% and 35.5%. Conclusions: Conformal plan is the best in radiotherapy, as it can provide ideal dose distribution of irradiated target with adequate protection of the normal tissues. Conventional four-field plan, being easy to carry, out, can replace the conformal plan in most situations. Conventional two-field has the most uneven dose distribution and largest lung volume irradiated. (authors)

Unraveling the Quaternary river incision in the Moselle valley (Rhenish Massif, Germany): new insights from cosmogenic nuclide dating (10Be/26Al) of the Main Terrace complex

Science.gov (United States)

Rixhon, Gilles; Cordier, Stéphane; Harmand, Dominique; May, Simon Matthias; Kelterbaum, Daniel; Dunai, Tibor; Binnie, Steven; Brückner, Helmut

2014-05-01

Throughout the whole river network of the Rhenish Massif, the terrace complex of the so-called Main Terrace forms the morphological transition between a wide upper palaeovalley (plateau valley) and a deeply incised lower valley. The youngest level of this Main Terrace complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature in the terrace flight; it is often used as a reference level to identify the start of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). The latter probably reflects the major tectonic pulse that affected the whole Massif and was related to an acceleration of the uplift rates (Demoulin & Hallot, 2009). The Main terraces are particularly well preserved in the lower Moselle valley and are characterized by a constant absolute elevation of their base along a 150 km-long reach. Despite that various hypotheses have been proposed to explain this horizontality (updoming, faulting...), all studies assumed an age of ca. 800 ka for the YMT, mainly based on the questionable extrapolation of palaeomagnetic data obtained in the Rhine valley. Therefore, a reliable chronological framework is still required to unravel the spatio-temporal characteristics of the Pleistocene evolution of the Moselle valley. In this study, we apply cosmogenic nuclide dating (10Be/26Al) to fluvial sediments pertaining to the Main Terrace complex or to the upper Middle Terraces. Several sites along the lower Moselle were sampled following two distinct sampling strategies: (i) depth profiles where the original terrace (palaeo-)surface is well preserved and did not experience much postdepositional burial (e.g., loess cover); and (ii) the isochron technique where the sediment thickness exceeds 3 m. Cosmogenic nuclide ages recently obtained for three rivers in the Meuse catchment in the western Rhenish Massif demonstrated that the Main Terraces were younger than expected and their abandonment was diachronic along the

Atmospheric dispersion experiments over complex terrain in a spanish valley site (Guardo-90)

International Nuclear Information System (INIS)

Ibarra, J.I.

1991-01-01

An intensive field experimental campaign was conducted in Spain to quantify atmospheric diffusion within a deep, steep-walled valley in rough, mountainous terrain. The program has been sponsored by the spanish companies of electricity and is intended to validate existing plume models and to provide the scientific basis for future model development. The atmospheric dispersion and transport processes in a 40x40 km domain were studied in order to evaluate SO 2 and SF 6 releases from an existing 185 m chimney and ground level sources in a complex terrain valley site. Emphasis was placed on the local mesoscale flows and light wind stable conditions. Although the measuring program was intensified during daytime for dual tracking of SO 2 /SF 6 from an elevated source, nighttime experiments were conducted for mountain-valley flows characterization. Two principle objectives were pursued: impaction of plumes upon elevated terrain, and diffusion of gases within the valley versus diffusion over flat, open terrain. Artificial smoke flows visualizations provided qualitative information: quantitative diffusion measurements were obtained using sulfur hexafluoride gas with analysis by highly sensitive electron capture gas chromatographs systems. Fourteen 2 hours gaseous tracer releases were conducted

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

Science.gov (United States)

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

2007-01-01

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

Green valley galaxies as a transition population in different environments

Science.gov (United States)

Coenda, Valeria; Martínez, Héctor J.; Muriel, Hernán

2018-02-01

We present a comparative analysis of the properties of passive, star-forming and transition (green valley) galaxies in four discrete environments: field, groups, the outskirts and the core of X-ray clusters. We construct samples of galaxies from the Sloan Digital Sky Survey in these environments so that they are bound to have similar redshift distributions. The classification of galaxies into the three sequences is based on the UV-optical colour NUV - r. We study a number of galaxy properties: stellar mass, morphology, specific star formation rate and the history of star formation. The analysis of green valley (GV) galaxies reveals that the physical mechanisms responsible for external quenching become more efficient moving from the field to denser environments. We confirm previous findings that GV galaxies have intermediate morphologies; moreover, we find that this appears to be independent of the environment. Regarding the stellar mass of GV galaxies, we find that they tend to be more massive in the field than in denser environments. On average, GV galaxies account for ∼ 20 per cent of all galaxies in groups and X-ray clusters. We find evidence that the field environment is inefficient in transforming low-mass galaxies. GV galaxies have average star formation histories intermediate between passive and star-forming galaxies, and have a clear and consistent dependence on the environment: both, the quenching time and the amplitude of the star formation rate, decrease towards higher density environments.

Quantum Hall Valley Nematics: From Field Theories to Microscopic Models

Science.gov (United States)

Parameswaran, Siddharth

The interplay between quantum Hall ordering and spontaneously broken ``internal'' symmetries in two-dimensional electron systems with spin or pseudospin degrees of freedom gives rise to a variety of interesting phenomena, including novel phases, phase transitions, and topological excitations. I will discuss a theory of broken-symmetry quantum Hall states, applicable to a class of multivalley systems, where the symmetry at issue is a point-group element that combines a spatial rotation with a permutation of valley indices. I will explore its ramifications for the phase diagram of a variety of experimental systems, such as AlAs and Si quantum wells and the surface states of bismuth. I will also discuss unconventional transport phenomena in these phases in the presence of quenched randomness, and the possible mechanisms of selection between degenerate broken-symmetry phases in clean systems. I acknowledge support from NSF DMR-1455366.

Assessment of bilayer silicene to probe as quantum spin and valley Hall effect

Science.gov (United States)

Rehman, Majeed Ur; Qiao, Zhenhua

2018-02-01

Silicene takes precedence over graphene due to its buckling type structure and strong spin orbit coupling. Motivated by these properties, we study the silicene bilayer in the presence of applied perpendicular electric field and intrinsic spin orbit coupling to probe as quantum spin/valley Hall effect. Using analytical approach, we calculate the spin Chern-number of bilayer silicene and then compare it with monolayer silicene. We reveal that bilayer silicene hosts double spin Chern-number as compared to single layer silicene and therefore accordingly has twice as many edge states in contrast to single layer silicene. In addition, we investigate the combined effect of intrinsic spin orbit coupling and the external electric field, we find that bilayer silicene, likewise single layer silicene, goes through a phase transitions from a quantum spin Hall state to a quantum valley Hall state when the strength of the applied electric field exceeds the intrinsic spin orbit coupling strength. We believe that the results and outcomes obtained for bilayer silicene are experimentally more accessible as compared to bilayer graphene, because of strong SO coupling in bilayer silicene.

Adaptation of a pattern-scaling approach for assessment of local (village/valley) scale water resources and related vulnerabilities in the Upper Indus Basin

Science.gov (United States)

Forsythe, Nathan; Kilsby, Chris G.; Fowler, Hayley J.; Archer, David R.

2010-05-01

The water resources of the Upper Indus Basin (UIB) are of the utmost importance to the economic wellbeing of Pakistan. The irrigated agriculture made possible by Indus river runoff underpins the food security for Pakistan's nearly 200 million people. Contributions from hydropower account for more than one fifth of peak installed electrical generating capacity in a country where widespread, prolonged load-shedding handicaps business activity and industrial development. Pakistan's further socio-economic development thus depends largely on optimisation of its precious water resources. Confident, accurate seasonal predictions of water resource availability coupled with sound understanding of interannual variability are urgent insights needed by development planners and infrastructure managers at all levels. This study focuses on the challenge of providing meaningful quantitative information at the village/valley scale in the upper reaches of the UIB. Proceeding by progressive reductions in scale, the typology of the observed UIB hydrological regimes -- glacial, nival and pluvial -- are examined with special emphasis on interannual variability for individual seasons. Variations in discharge (runoff) are compared to observations of climate parameters (temperature, precipitation) and available spatial data (elevation, snow cover and snow-water-equivalent). The first scale presented is composed of the large-scale, long-record gauged UIB tributary basins. The Pakistan Water and Power Development Authority (WAPDA) has maintained these stations for several decades in order to monitor seasonal flows and accumulate data for design of further infrastructure. Data from basins defined by five gauging stations on the Indus, Hunza, Gilgit and Astore rivers are examined. The second scale presented is a set of smaller gauged headwater catchments with short records. These gauges were installed by WAPDA and its partners amongst the international development agencies to assess potential

REVEAL II: Seasonality and spatial variability of particle and visibility conditions in the Fraser Valley

DEFF Research Database (Denmark)

Pryor, S.C.; Barthelmie, R.J.

2000-01-01

This paper presents data collected during a year-long field experiment (REVEAL II) in the Fraser Valley, British Columbia. The data are used to provide information regarding ambient visibility conditions and fine particle concentrations in the valley. Although average fine mass measured during RE...... taken at a number of sites during REVEAL II are used to evaluate a simple method for obtaining (classed) quantitative estimates of visual range from this medium without requiring access to specialized instrumentation. (C) 2000 Elsevier Science B.V. All rights reserved....

Refining the Subseafloor Circulation Model of the Middle Valley Hydrothermal System Using Fluid Geochemistry

Science.gov (United States)

Inderbitzen, K. E.; Wheat, C. G.; Baker, P. A.; Fisher, A. T.

2014-12-01

Currently, fluid circulation patterns and the evolution of rock/fluid compositions as circulation occurs in subseafloor hydrothermal systems are poorly constrained. Sedimented spreading centers provide a unique opportunity to study subsurface flow because sediment acts as an insulating blanket that traps heat from the cooling magma body and limits: (a) potential flow paths for seawater to recharge the aquifer in permeable upper basaltic basement and (b) points of altered fluid egress. This also allows for a range of thermal and geochemical gradients to exist near the sediment-water interface. Models of fluid circulation patterns in this type of hydrologic setting have been generated (eg. Stein and Fisher, 2001); however fluid chemistry datasets have not previously been used to test the model's viability. We address this issue by integrating the existing circulation model with fluid compositional data collected from sediment pore waters and high temperature hydrothermal vents located in Middle Valley on the Juan de Fuca Ridge. Middle Valley hosts a variety of hydrologic regimes: including areas of fluid recharge (Site 855), active venting (Site 858/1036; Dead Dog vent field), recent venting (Site 856/1035; Bent Hill Massive Sulfide deposit) and a section of heavily sedimented basement located between recharge and discharge sites (Site 857). We will present new results based on thermal and geochemical data from the area of active venting (Sites 858 and 1036), that was collected during Ocean Drilling Program Legs 139 and 169 and a subsequent heat flow/gravity coring effort. These results illuminate fine scale controls on secondary recharge and fluid flow within the sediment section at Site 858/1036. The current status of high temperature vents in this area (based on observations made in July, 2014) will also be outlined.

Superfund Record of Decision (EPA Region 9): North Hollywood/Burbank Well Field Area 1, San Fernando Valley Site, California (first remedial action), September 1987. Final report

Energy Technology Data Exchange (ETDEWEB)

1987-09-24

The North Hollywood - Burbank Well Field (NHBWF) is located within the San Fernando Valley Ground Water basin, which can provide drinking water for approximately 500,000 people residing in the San Fernando Valley and Los Angeles. In 1980 TCE and PCE were discovered in 25% of DWP's wells. In July 1981, DWP and the Southern California Association of Governments began a two-year study funded by EPA. The study revealed the occurrence of ground-water contamination plume patterns that are spreading toward the southeast. The primary contaminant of concern to the ground-water is TCE with PCE and other VOCs present. The selected remedial action for the site is ground-water pump and treatment using aeration and granular-activated-carbon - air-filtering units, with discharge to the DWP Pumping Station for chlorination and distribution. Spent carbon will be removed and replaced with fresh carbon, with the spent carbon scheduled either for disposal or regeneration. The estimated capital cost for this remedial action is $2,192,895 with present worth OandM of $2,284,105.

An improved data integration algorithm to constrain the 3D displacement field induced by fast deformation phenomena tested on the Napa Valley earthquake

Science.gov (United States)

Polcari, Marco; Fernández, José; Albano, Matteo; Bignami, Christian; Palano, Mimmo; Stramondo, Salvatore

2017-12-01

In this work, we propose an improved algorithm to constrain the 3D ground displacement field induced by fast surface deformations due to earthquakes or landslides. Based on the integration of different data, we estimate the three displacement components by solving a function minimization problem from the Bayes theory. We exploit the outcomes from SAR Interferometry (InSAR), Global Positioning System (GNSS) and Multiple Aperture Interferometry (MAI) to retrieve the 3D surface displacement field. Any other source of information can be added to the processing chain in a simple way, being the algorithm computationally efficient. Furthermore, we use the intensity Pixel Offset Tracking (POT) to locate the discontinuity produced on the surface by a sudden deformation phenomenon and then improve the GNSS data interpolation. This approach allows to be independent from other information such as in-situ investigations, tectonic studies or knowledge of the data covariance matrix. We applied such a method to investigate the ground deformation field related to the 2014 Mw 6.0 Napa Valley earthquake, occurred few kilometers from the San Andreas fault system.

Tunable Acoustic Valley-Hall Edge States in Reconfigurable Phononic Elastic Waveguides

Science.gov (United States)

Liu, Ting-Wei; Semperlotti, Fabio

2018-01-01

We investigate the occurrence of acoustic topological edge states in a 2D phononic elastic waveguide due to a phenomenon that is the acoustic analog of the quantum valley Hall effect. We show that a topological transition takes place between two lattices having broken space-inversion symmetry due to the application of a tunable strain field. This condition leads to the formation of gapless edge states at the domain walls, as further illustrated by the analysis of the bulk-edge correspondence and of the associated topological invariants. Interestingly, topological edge states can also be triggered at the boundary of a single domain, when boundary conditions are properly selected. We also show that the static modulation of the strain field allows us to tune the response of the material between the different supported edge states. Although time-reversal symmetry is still intact in this material system, the edge states are topologically protected when intervalley mixing is either weak or negligible. This characteristic enables selective valley injection, which is achieved via synchronized source strategy.

Hydrogeology and water quality of the Shell Valley Aquifer, Rolette County, North Dakota

Science.gov (United States)

Strobel, M.L.

1997-01-01

The Shell Valley aquifer is the sole source of water for the city of Belcourt and the primary source of water for most of the Turtle Mountain Indian Reservation. The Turtle Mountain Band of Chippewa Indians is concerned about the quantity and quality of water in the Shell Valley aquifer, which underlies about 56 square miles in central Rolette County and has an average saturated thickness of about 35 feet. Water levels across most of the Shell Valley aquifer fluctuate with variations in precipitation but generally are stable. Withdrawals from the north well field decreased slightly during 1976-95, but withdrawals from the south well field increased during 1983-95. Water levels in the south well field declined as withdrawals increased. The average decline during the last 8 years was about 1.75 feet per year. The water level has reached the well screen in at least one of the production wells. Most of the water in the aquifer is a bicarbonate type and has dissolved-solids concentrations ranging from 479 to 1,510 milligrams per liter. None of the samples analyzed had detectable concentrations of pesticides, but hydrocarbons were detected in both ground- and surfacewater samples. Polycyclic aromatic hydrocarbons (PAH) were the most frequently detected hydrocarbons. Benzene, toluene, ethylbenzene, and xylene (BTEX), polychlorinated biphenyls (PCB), and pentachlorophenol (PCP) also were detected.Generally, the Shell Valley aquifer is an adequate source of water for current needs, but evaluation of withdrawals in relation to a knowledge of aquifer hydrology would be important in quantifying sustainable water supplies. Water quality in the aquifer generally is good; the Turtle Mountain Band of Chippewa Indians filters the water to reduce concentrations of dissolved constituents. Hydrocarbons, although present in the aquifer, have not been quantified and may not pose a general health risk. Further analysis of the quantity and distribution of the hydrocarbons would be useful

27 CFR 9.27 - Lime Kiln Valley.

Science.gov (United States)

2010-04-01

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

An Evaluation of Mesoscale Model Predictions of Down-Valley and Canyon Flows and Their Consequences Using Doppler Lidar Measurements During VTMX 2000

International Nuclear Information System (INIS)

Fast, Jerome D.; Darby, Lisa S.

2004-01-01

A mesoscale model, a Lagrangian particle dispersion model, and extensive Doppler lidar wind measurements during the VTMX 2000 field campaign were used to examine converging flows over the Salt Lake Valley and their effect on vertical mixing of tracers at night and during the morning transition period. The simulated wind components were transformed into radial velocities to make a direct comparison with about 1.3 million Doppler lidar data points and critically evaluate, using correlation coefficients, the spatial variations in the simulated wind fields aloft. The mesoscale model captured reasonably well the general features of the observed circulations including the daytime up-valley flow, the nighttime slope, canyon, and down-valley flows, and the convergence of the flows over the valley. When there were errors in the simulated wind fields, they were usually associated with the timing, structure, or strength of specific flows. Simulated outflows from canyons along the Wasatch Mountains propagated over the valley and converged with the down-valley flow, but the advance and retreat of these simulated flows was often out of phase with the lidar measurements. While the flow reversal during the evening transition period produced rising motions over much of the valley atmosphere in the absence of significant ambient winds, average vertical velocities became close to zero as the down-valley flow developed. Still, vertical velocities between 5 and 15 cm s-1 occurred where down-slope, canyon and down-valley flows converged and vertical velocities greater than 50 cm s-1 were produced by hydraulic jumps at the base of the canyons. The presence of strong ambient winds resulted in smaller average rising motions during the evening transition period and larger average vertical velocities after that. A fraction of the tracer released at the surface was transported up to the height of the surrounding mountains; however, higher concentrations were produced aloft for evening s

Latest Pleistocene and Holocene surficial deposits and landforms of Yosemite Valley, California

Science.gov (United States)

Haddon, E. K.; Stock, G. M.; Booth, D. B.

2016-12-01

Field studies on the surficial geology and geomorphology of Yosemite Valley since the 1870's formed an early basis for our understanding of Quaternary landscape evolution in the central Sierra Nevada. These landmark studies described the erosional origin of Yosemite's iconic scenery, but left details of the latest Pleistocene and Holocene sedimentary record for later investigation. We combined mapping of deposits and landforms with geochronology to reconstruct the geomorphic evolution of Yosemite Valley since the 15 ka retreat of the Last Glacial Maximum (LGM) valley glacier. We document a sustained period of relative landscape stability, characterized by valley-bottom aggradation of glacial till, fluvial sediments, and lacustrine silts, as well as valley-margin accumulation of talus and fan alluvium. Recessional moraines, episodically emplaced rock avalanches, and alluvial fans impeded surface flow and controlled the local base level. This predominantly aggradational regime then shifted to incision in the earliest Holocene, likely due to a diminishing supply of glacial sediment, and created a flight of fluvial terraces inset by up to 9 m. The volume of fringing talus and fan alluvium in comparison with fluvial terrace sequences emphasizes the importance of valley-wall erosion as a sediment source. Cosmogenic 10Be exposure ages from rock avalanche boulders and 14C charcoal ages from deltaic sequences and inset fluvial gravels suggest variable rates of Holocene river incision. Although some incision events likely record local base level changes at the El Capitan LGM recessional moraine, the presence of perched, well-developed outwash terraces downstream indicates a more regional climatic forcing. These findings, including the depositional record of land-use disturbances over the past two centuries, help illuminate the geologic evolution of this celebrated landscape and inform ongoing river-restoration work.

Holocene evolution of the Tonle Sap Lake: valley network infill and rates of sedimentation in Cambodia's Great Lake

Science.gov (United States)

Best, J.; Darby, S. E.; Langdon, P. G.; Hackney, C. R.; Leyland, J.; Parsons, D. R.; Aalto, R. E.; Marti, M.

2017-12-01

Tonle Sap Lake, the largest freshwater lake in SE Asia (c. 120km long and 35 km wide), is a vital ecosystem that provides 40-60% of the protein for the population of Cambodia. The lake is fed by flow from the Mekong River that causes the lake rise in level by c. 8m during monsoonal and cyclone-related floods, with drainage of the lake following the monsoon. Hydropower dam construction on the Mekong River has raised concerns as to the fragility of the Tonle Sap habitat due to any changing water levels and sedimentation rates within the lake. This paper details results of sub-bottom profiling surveys of Tonle Sap Lake in October 2014 that detailed the stratigraphy of the lake and assessed rates of infill. An Innomar Parametric Echo Sounder (PES) was used to obtain c. 250 km of sub-bottom profiles, with penetration up to 15m below the lake bed at a vertical resolution of c. 0.20m. These PES profiles were linked to cores from the north of the lake and previous literature. The PES profiles reveal a network of valleys, likely LGM, with relief up to c. 15-20m, that have been infilled by a suite of Holocene sediments. The valley surface is picked out as a strong reflector throughout the lake, and displays a series of valleys that are up to c. 15m deep and commonly 50-200m wide, although some of the largest valleys are 1.2km in width. Modelling of channel network incision during LGM conditions generates landscapes consistent with our field observations. The Tonle Sap valley network is infilled by sediments that show firstly fluvial and/or subaerial slope sedimentation, and then by extensive, parallel-bedded, lacustrine sedimentation. Lastly, the top c. 1m of sedimentation is marked by a distinct basal erosional surface that can be traced over much of the Tonle Sap Lake, and that is overlain by a series of parallel PES reflections. This upper sediment layer is interpreted to represent sedimentation in the Tonle Sap lake due to sediment suspension settling but after a period

Crustal and upper mantle velocity structure of the Salton Trough, southeast California

Science.gov (United States)

Parsons, T.; McCarthy, J.

1996-01-01

This paper presents data and modelling results from a crustal and upper mantle wide-angle seismic transect across the Salton Trough region in southeast California. The Salton Trough is a unique part of the Basin and Range province where mid-ocean ridge/transform spreading in the Gulf of California has evolved northward into the continent. In 1992, the U.S. Geological Survey (USGS) conducted the final leg of the Pacific to Arizona Crustal Experiment (PACE). Two perpendicular models of the crust and upper mantle were fit to wide-angle reflection and refraction travel times, seismic amplitudes, and Bouguer gravity anomalies. The first profile crossed the Salton Trough from the southwest to the northeast, and the second was a strike line that paralleled the Salton Sea along its western edge. We found thin crust (???21-22 km thick) beneath the axis of the Salton Trough (Imperial Valley) and locally thicker crust (???27 km) beneath the Chocolate Mountains to the northeast. We modelled a slight thinning of the crust further to the northeast beneath the Colorado River (???24 km) and subsequent thickening beneath the metamorphic core complex belt northeast of the Colorado River. There is a deep, apparently young basin (???5-6 km unmetamorphosed sediments) beneath the Imperial Valley and a shallower (???2-3 km) basin beneath the Colorado River. A regional 6.9-km/s layer (between ???15-km depth and the Moho) underlies the Salton Trough as well as the Chocolate Mountains where it pinches out at the Moho. This lower crustal layer is spatially associated with a low-velocity (7.6-7.7 km/s) upper mantle. We found that our crustal model is locally compatible with the previously suggested notion that the crust of the Salton Trough has formed almost entirely from magmatism in the lower crust and sedimentation in the upper crust. However, we observe an apparently magmatically emplaced lower crust to the northeast, outside of the Salton Trough, and propose that this layer in part

Simulation of ground-water flow and land subsidence in the Antelope Valley ground-water basin, California

Science.gov (United States)

Leighton, David A.; Phillips, Steven P.

2003-01-01

Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley ground-water basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, ground water provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most ground-water pumping in the valley occurs in the Antelope Valley ground-water basin, which includes the rapidly growing cities of Lancaster and Palmdale. Ground-water-level declines of more than 200 feet in some parts of the ground-water basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may continue to increase reliance on ground water. To better understand the ground-water flow system and to develop a tool to aid in effectively managing the water resources, a numerical model of ground-water flow and land subsidence in the Antelope Valley ground-water basin was developed using old and new geohydrologic information. The ground-water flow system consists of three aquifers: the upper, middle, and lower aquifers. The aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to ground-water development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Ground water flowed from the recharge areas to discharge areas around the playas where it discharged either from the aquifer system as evapotranspiration or from springs. Partial barriers to horizontal ground-water flow, such as faults, have been identified in the ground-water basin. Water-level declines owing to

Documentation of the Santa Clara Valley regional ground-water/surface-water flow model, Santa Clara Valley, California

Science.gov (United States)

Hanson, R.T.; Li, Zhen; Faunt, C.C.

2004-01-01

into upper- and lower-aquifer systems. Ground-water inflow occurs as natural recharge in the form of streamflow infiltration and areal infiltration of precipitation along stream channels, artificial recharge from infiltration of imported water at recharge ponds and along selected stream channels, and leakage along selected transmission pipelines. Ground-water outflow occurs as evapotranspiration, stream base flow, discharge through pumpage from wells, and subsurface flow to the San Francisco Bay. The geohydrologic framework of the regional ground-water flow system was represented as six model layers. The hydraulic properties were redefined on the basis of cell-based lithologic properties that were delineated in terms of aggregate thicknesses of coarse-grained, fine-grained, and mixed textural categories. The regional aquifer systems also are dissected by several laterally extensive faults that may form at least partial barriers to the lateral flow of ground water. The spatial extent of the ground-water flow model was extended and refined to cover the entire Santa Clara Valley, including the Evergreen subregion. The temporal discretization was refined and the period of simulation was extended to 197099. The model was upgraded to MODFLOW-2000 (MF2K) and was calibrated to fit historical ground-water levels, streamflow, and land subsidence for the period 197099. The revised model slightly overestimates measured water levels with an root-mean-square error of -7.34 feet. The streamflow generally shows a good match on gaged creeks and rivers for flows greater than 1.2 cubic feet per second. The revised model also fits the measured deformation at the borehole extensometer site located near San Jose within 16 to 27 percent and the extensometer site near Sunnyvale within 3 percent of the maximum measured seasonal deformation for the deepest extensometers. The total ground-water inflow and outflow of about 225,500 acre-feet per

Electrical valley filtering in transition metal dichalcogenides

Science.gov (United States)

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

2018-03-01

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

Water resources of Parowan Valley, Iron County, Utah

Science.gov (United States)

Marston, Thomas M.

2017-08-29

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

Valley-Fill Standstones in the Kootenai Formation on the Crow Indian Reservation, South-Central Montana

Energy Technology Data Exchange (ETDEWEB)

David A. Lopez

1998-01-07

Subsurface data is being collected, organized, and a digital database is being prepared. An ACCESS database and PC-Arcview if being used to manage and interpret the data. Well data and base map have been successfully imported to Arcview and customized. All of the four 30 feet by 60 feet geologic surface geologic quadrangles have been scanned to produce a digital surface data base for the Crow Reservation. Field investigations inventoried for the presence of valley-fill deposits. These appear to represent at least a four major westward-trending valley systems.

Bedrock Geology and Asbestos Deposits of the Upper Missisquoi Valley and Vicinity, Vermont

Science.gov (United States)

Cady, Wallace Martin; Albee, Arden Leroy; Chidester, A.H.

1963-01-01

The upper Missisquoi Valley and vicinity as described in this report covers an area of about 250 square miles at the headwaters of the Missisquoi River in north-central Vermont. About 90 percent of the area is forested and the remainder is chiefly farm land. The topography reflects the geologic structure and varied resistance of the bedrock to erosion. Most of the area is on the east limb of the Green Mountain anticlinorium, which is the principal structural feature of Vermont. The bedrock is predominantly sedimentary and volcanic rock that has been regionally metamorphosed. It was intruded before metamorphism by mafic and ultramafic igneous rocks, and after metamorphism by felsic and mafic igneous rocks. The metamorphosed sedimentary and volcanic rocks range in age from Cambrian(?) to Middle Silurian, the intrusive igneous rocks from probably Late Ordovician to probably late Permian. Metamorphism and principal folding in the region occurred in Middle Devonian time. The metamorphosed sedimentary and volcanic rocks make up a section at least 25,000 feet thick and can be divided into nine formations. The Hazens Notch formation of Cambrian(?) and Early Cambrian age is characterized by carbonaceous schist. It is succeeded in western parts of the area by the Jay Peak formation of Early Cambrian age, which is chiefly a schist that is distinguished by the general absence of carbonaceous zones; in central parts of the area the Hazens Notch formation is followed by the Belvidere Mountain amphibolite, probably the youngest of the formations of Early Cambrian age. The Ottauquechee formation, composed of carbonaceous phyllite and quartzite, and phyllitic graywacke, is of Middle Cambrian age. The Stowe formation of Late Cambrian(?) and Early(?) Ordovician age overlies the Ottauquechee and is predominantly noncarbonaceous schist, though it also contains greenstone and carbonaceous schist and phyllite. The Umbrella Hill formation of Middle Ordovician age is characteristically a

EPA Region 1 - Valley Depth in Meters

Science.gov (United States)

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

Optically initialized robust valley-polarized holes in monolayer WSe2

KAUST Repository

Hsu, Wei-Ting

2015-11-25

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

Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq)

Science.gov (United States)

Sharbazheri, Khalid Mahmood; Ghafor, Imad Mahmood; Muhammed, Qahtan Ahmad

2009-10-01

The Cretaceous/Tertiary (K/T) boundary sequence, which crops out in the studied area is located within the High Folded Zone, in the Sirwan Valley, northeastern Iraq. These units mainly consist of flysch and flysch-type successions of thick clastic beds of Tanjero/Kolosh Formations. A detailed lithostratigraphic study is achieved on the outcropping uppermost part of the Upper Cretaceous successions (upper part of Tanjero Formation) and the lowermost part of the Kolosh Formation. On the basis of the identified planktonic foraminiferal assemblages, five biozones are recorded from the uppermost part of Tanjero Formation and four biozones from the lower part of the Kolosh Formation (Lower Paleocene) in the Sirwan section. The biostratigraphic correlations based on planktonic foraminiferal zonations showed a comparison between the biostratigraphic zones established in this study and other equivalents of the commonly used planktonic zonal scheme around the Cretaceous/Tertiary boundary in and outside Iraq.

Examining Dimethyl Sulfide Emissions in California's San Joaquin Valley

Science.gov (United States)

Huber, D.; Hughes, S.; Blake, D. R.

2017-12-01

Dimethyl Sulfide (DMS) is a sulfur-containing compound that leads to the formation of aerosols which can lead to the formation of haze and fog. Whole air samples were collected on board the NASA C-23 Sherpa aircraft during the 2017 Student Airborne Research Program (SARP) over dairies and agricultural fields in the San Joaquin Valley. Analysis of the samples indicate average DMS concentrations of 23 ± 9 pptv, with a maximum concentration of 49 pptv. When compared with DMS concentrations from previous SARP missions (2009-2016), 2017 by far had the highest frequency of elevated DMS in this region. For this study, agricultural productivity of this region was analyzed to determine whether land use could be contributing to the elevated DMS. Top down and bottom up analysis of agriculture and dairies were used to determine emission rates of DMS in the San Joaquin Valley. Correlations to methane and ethanol were used to determine that DMS emissions were strongly linked to dairies, and resulted in R2 values of 0.61 and 0.43, respectively. These values indicate a strong correlation between dairies and DMS emissions. Combined with NOAA HySPLIT back trajectory data and analysis of ground air samples, results suggest that the contribution of dairies to annual DMS emissions in the San Joaquin Valley exceeds those from corn and alfalfa production.

Geologic evaluation of the Oasis Valley basin, Nye County, Nevada

Energy Technology Data Exchange (ETDEWEB)

Fridrich, C.J.; Minor, S.A.; and Mankinen, E.A.

2000-01-13

This report documents the results of a geologic study of the area between the underground-nuclear-explosion testing areas on Pahute Mesa, in the northwesternmost part of the Nevada Test Site, and the springs in Oasis Valley, to the west of the Test Site. The new field data described in this report are also presented in a geologic map that is a companion product(Fridrich and others, 1999) and that covers nine 7.5-minute quadrangles centered on Thirsty Canyon SW, the quadrangle in which most of the Oasis Valley springs are located. At the beginning of this study, published detailed maps were available for 3 of the 9 quadrangles of the study area: namely Thirsty Canyon (O'Connor and others, 1966); Beatty (Maldonado and Hausback, 1990); and Thirsty Canyon SE (Lipman and others, 1966). Maps of the last two of these quadrangles, however, required extensive updating owing to recent advances in understanding of the regional structure and stratigraphy. The new map data are integrated in this re port with new geophysical data for the Oasis Valley area, include gravity, aeromagnetic, and paleomagnetic data (Grauch and others, 1997; written comm., 1999; Mankinen and others, 1999; Hildenbrand and others, 1999; Hudson and others, 1994; Hudson, unpub. data).

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

Science.gov (United States)

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

2009-01-01

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

Tree culture of smallholder farmers practicing agroforestry in Gunung Salak Valley, West Java, Indonesia

DEFF Research Database (Denmark)

Rahman, Syed Ajijur; Sunderland, Terry; Roshetko, James M.

2016-01-01

This paper investigates the types of agroforestry system that exist in Gunung Salak Valley, West Java, Indonesia in order to characterize the differences in their basic structure and associated crop plant diversity. Data were collected through rapid rural appraisal, field observation and focus...

Recursive stochastic effects in valley hybrid inflation

Science.gov (United States)

Levasseur, Laurence Perreault; Vennin, Vincent; Brandenberger, Robert

2013-10-01

Hybrid inflation is a two-field model where inflation ends because of a tachyonic instability, the duration of which is determined by stochastic effects and has important observational implications. Making use of the recursive approach to the stochastic formalism presented in [L. P. Levasseur, preceding article, Phys. Rev. D 88, 083537 (2013)], these effects are consistently computed. Through an analysis of backreaction, this method is shown to converge in the valley but points toward an (expected) instability in the waterfall. It is further shown that the quasistationarity of the auxiliary field distribution breaks down in the case of a short-lived waterfall. We find that the typical dispersion of the waterfall field at the critical point is then diminished, thus increasing the duration of the waterfall phase and jeopardizing the possibility of a short transition. Finally, we find that stochastic effects worsen the blue tilt of the curvature perturbations by an O(1) factor when compared with the usual slow-roll contribution.

New records of Pteridophytes for Kashmir Valley, India

Directory of Open Access Journals (Sweden)

SHAKOOR A. MIR

2014-10-01

Full Text Available Mir SA, Mishra AK, Reshi ZA, Sharma MP. 2014. New Records of Pteridophytes for Kashmir Valley, India. Biodiversitas 15: 131-136. During the recent field survey of district Shopian four species of Pteridophytes are reported for the first time that constitutes new records for Kashmir valley. These species are Hypolepis polypodioides (Blume Hook, Pteris stenophylla Wall. ex Hook. & Grev., Dryopteris subimpressa Loyal and Dryopteris wallichiana (Spreng. Hylander. The diagnostic features of H. polypodioides are presence of long-creeping slender rhizome and eglandular, colorless or brown tinged hairs throughout the frond. P. stenophylla is characterized by having dimorphic fronds and 3 to 5 pinnae clustered at stipe apex. D. subimpressa is marked by pale-green lamina and the largest basiscopic basal pinnule in the lowest pair of pinnae. Similarly, the characteristic features of D. wallichiana are presence of huge frond size, glossier and dark-green lamina and dense browner scales in stipe and rachis. In present communication taxonomic description, synonyms, ecology and photographs are provided for each of these newly recorded species.

Influence of the orographic roughness of glacier valleys across the Transantarctic Mountains in an atmospheric regional model

Energy Technology Data Exchange (ETDEWEB)

Jourdain, Nicolas C.; Gallee, Hubert [Laboratoire de Glaciologie et Geophysique de l' Environnement, Saint Martin d' Heres (France)

2011-03-15

Glacier valleys across the Transantarctic Mountains are not properly taken into account in climate models, because of their coarse resolution. Nonetheless, glacier valleys control katabatic winds in this region, and the latter are thought to affect the climate of the Ross Sea sector, frsater formation to snow mass balance. The purpose of this paper is to investigate the role of the production of turbulent kinetic energy by the subgrid-scale orography in the Transantarctic Mountains using a 20-km atmospheric regional model. A classical orographic roughness length parametrization is modified to produce either smooth or rough valleys. A one-year simulation shows that katabatic winds in the Transantarctic Mountains are strongly improved using smooth valleys rather than rough valleys. Pressure and temperature fields are affected by the representation of the orographic roughness, specifically in the Transantarctic Mountains and over the Ross Ice Shelf. A smooth representation of escarpment regions shows better agreement with automatic weather station observations than a rough representation. This work stresses the need to improve the representation of subgrid-scale orography to simulate realistic katabatic flows. This paper also provides a way of improving surface winds in an atmospheric model without increasing its resolution. (orig.)

The Spread of Islam in the Niger and Senegal Valleys before the Rise of Almoravids

Directory of Open Access Journals (Sweden)

Ahmed Elyas Hussein

2001-12-01

Full Text Available This study traces the early contacts of the middle and upper Niger and Senegal Rivers with the Muslims in the first five centuries after hijrah and shows the spread of Islam and the rise of states long before the emergence of Al-Moravids. It analyses the early Muslim expansion in the Western Sahara, the role of the Ibāḍiyyah in central Sahara and the efforts of the Sanhadja in the Western Sahara which resulted in the spread of Islam and rise of Islamic kingdoms in the Niger and the Senegal Valleys before the 5th centaury AH.

Seafloor Uplift in Middle Valley, Juan de Fuca Ridge: New High-Resolution Pressure Data

Science.gov (United States)

Inderbitzen, K. E.; Becker, K.; Davis, E. E.

2011-12-01

Currently, in-situ seafloor and basement pressures are continuously monitored and recorded by an ODP subseafloor hydrogeological observatory (CORK) located in Middle Valley, Juan de Fuca Ridge. Hole 857D was drilled in 1991 in thickly sedimented crust to a depth of 936 mbsf and instrumented with an original CORK that was replaced in 1996. A large hydrothermal field (Dead Dog) lies roughly 1.7 km north of the hole, and two isolated chimneys and several diffuse flow sites are located ~800 meters northeast. The borehole and the vent fields have been visited periodically by submersible/ROV since 1999. Recent results from the CORK at 857D have shown apparent seafloor uplift, supported by depth records from the submersible Alvin. A constant rate of pressure change of ~6 kPa/yr, from its initiation in 2005 to the visit in 2010, has reduced mean seafloor pressure by ~28 kPa, equivalent to nearly 3 meters of head. This uplift rate is several times the typical pre-eruption inflation rates observed at Axial Seamount further south along the Juan de Fuca Ridge. Initially, the apparent uplift at 857D did not seem to have any effect on local high-temperature hydrothermal venting, however recent operations in Middle Valley revealed distinct changes at not only the hydrothermal field to the northeast, but also a shutdown of high-temperature venting to the north of 857D. We will present new data from Middle Valley, including the first year of data collected by a high-resolution pressure data logger deployed at 857D in June, 2010.

Hydrological functioning of West-African inland valleys explored with a critical zone model

Science.gov (United States)

Hector, B.; Cohard, J. M.; Séguis, L.; Peugeot, C.; Galle, S.

2017-12-01

In west Africa, recurrent floods are still a major issue, and hydropower has been recognized as an important development pathway. Furthermore, inland valleys carry an important agronomic potential, which could meet the necessary increase of the crop production associated with the strong demographic rates of the region. This can lead to land cover and subsequent hydrologic changes. However, the hydrological role of the inland valleys in the humid, hard rock-dominated Sudanian area is not yet well understood, specifically for streamflow (Q) generation processes. We address both the questions of the hydrological functioning of inland valleys in the Sudanian area of West-Africa and the impact of land cover changes on these systems through deterministic sensitivity experiments using a physically-based critical zone model (ParFlow-CLM) applied on a synthetic catchment which comprises an inland valley. The conceptual lithological/pedological model for the catchment includes the main features of such a hydrological elementary unit derived from the literature and from a previously published model based on data from a highly instrumented elementary catchment. Model forcings and parameters are based on data from the AMMA-CATCH observation service and multiple field experiments. We found yearly water budgets were much more sensitive to vegetation distribution than lithology features of the inland valley (presence of the low permeability layer commonly found below the inland valley and the hydrodynamic properties of upstream and lateral areas). Yearly evapotranspiration budget between a fully tree-covered and an herbaceous-covered catchment increases between 6 and 21% of the precipitation of the year (depending on the tested cases) which reduces considerably the yearly streamflow budgets ( 30%). On the other hand, the lithology distribution has clear impacts on the spatial distribution of water storage dynamics.

78 FR 7808 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Buffalo Valley...

Science.gov (United States)

2013-02-04

... amended, the Bureau of Land Management (BLM) Mount Lewis Field Office, Battle Mountain, Nevada, intends to... Buffalo Valley Mine Project, a proposed open pit gold mine, mill, and associated facilities, located on..._mountain_field.html . In order to be considered during the preparation of the Draft EIS, all comments must...

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

Energy Technology Data Exchange (ETDEWEB)

1981-10-01

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

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

International Nuclear Information System (INIS)

1981-10-01

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

Ballistic electron transport calculation of strained germanium-tin fin field-effect transistors

International Nuclear Information System (INIS)

Lan, H.-S.; Liu, C. W.

2014-01-01

The dependence of ballistic electron current on Sn content, sidewall orientations, fin width, and uniaxial stress is theoretically studied for the GeSn fin field-effect transistors. Alloying Sn increases the direct Γ valley occupancy and enhances the injection velocity at virtual source node. (112 ¯ ) sidewall gives the highest current enhancement due to the rapidly increasing Γ valley occupancy. The non-parabolicity of the Γ valley affects the occupancy significantly. However, uniaxial tensile stress and the shrinkage of fin width reduce the Γ valley occupancy, and the currents are enhanced by increasing occupancy of specific indirect L valleys with high injection velocity

Sustainable agricultural development in inland valleys

NARCIS (Netherlands)

Zwart, S.J.

2018-01-01

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

Transgressive systems tract development and incised-valley fills within a quaternary estuary-shelf system: Virginia inner shelf, USA

Science.gov (United States)

Foyle, A.M.; Oertel, G.F.

1997-01-01

High-frequency Quaternary glacioeustasy resulted in the incision of six moderate- to high-relief fluvial erosion surfaces beneath the Virginia inner shelf and coastal zone along the updip edges of the Atlantic continental margin. Fluvial valleys up to 5 km wide, with up to 37 m of relief and thalweg depths of up to 72 m below modern mean sea level, cut through underlying Pleistocene and Mio-Pliocene strata in response to drops in baselevel on the order of 100 m. Fluvially incised valleys were significantly modified during subsequent marine transgressions as fluvial drainage basins evolved into estuarine embayments (ancestral generations of the Chesapeake Bay). Complex incised-valley fill successions are bounded by, or contain, up to four stacked erosional surfaces (basal fluvial erosion surface, bay ravinement, tidal ravinement, and ebb-flood channel-base diastem) in vertical succession. These surfaces, combined with the transgressive oceanic ravinement that generally caps incised-valley fills, control the lateral and vertical development of intervening seismic facies (depositional systems). Transgressive stratigraphy characterizes the Quaternary section beneath the Virginia inner shelf where six depositional sequences (Sequences I-VI) are identified. Depositional sequences consist primarily of estuarine depositional systems (subjacent to the transgressive oceanic ravinement) and shoreface-shelf depositional systems; highstand systems tract coastal systems are thinly developed. The Quaternary section can be broadly subdivided into two parts. The upper part contains sequences consisting predominantly of inner shelf facies, whereas sequences in the lower part of the section consist predominantly of estuarine facies. Three styles of sequence preservation are identified. Style 1, represented by Sequences VI and V, is characterized by large estuarine systems (ancestral generations of the Chesapeake Bay) that are up to 40 m thick, have hemicylindrical wedge geometries

Groundwater availability of the Central Valley Aquifer, California

Science.gov (United States)

Faunt, Claudia C.

2009-01-01

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

Geotechnical analysis of soil samples from test trench at Western New York Nuclear Service Center, West Valley, New York

International Nuclear Information System (INIS)

Fickies, R.H.; Fakundiny, R.H.; Mosley, E.T.

1979-04-01

In July 1977, a deep research trench was excavated and soil samples collected at the Western New York Nuclear Services Center, West Valley, NY. The glacial till horizons sampled are considered to be representative of the till serving as a burial medium at the nearby low-level radioactive waste burial ground. A series of laboratory tests were conducted consisting of unit weight, moisture content, Atterberg limits, unconfined compression, dispersion, swell, permeability, and consolidation. These laboratory analyses and field observations indicate that the till exposed in the research trench is a generally dense mixture of silt and clay of low to medium plasticity, with minor amounts of fine to coarse sand and fine gravel. The till has a generally low coefficient of permeability in the range of 10 -7 cm/s horizontal and 10 -8 cm/s vertical. A network of vertical fractures exists in the upper 15 feet of weathered till which may allow some downward percolation of surface runoff. The test data indicates that the maximum depth to which these fractures could possibly penetrate is 50 feet

Geomorphic legacy of medieval Himalayan earthquakes in the Pokhara Valley

Science.gov (United States)

Schwanghart, Wolfgang; Bernhardt, Anne; Stolle, Amelie; Hoelzmann, Philipp; Adhikari, Basanta R.; Andermann, Christoff; Tofelde, Stefanie; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

2016-04-01

The Himalayas and their foreland belong to the world's most earthquake-prone regions. With millions of people at risk from severe ground shaking and associated damages, reliable data on the spatial and temporal occurrence of past major earthquakes is urgently needed to inform seismic risk analysis. Beyond the instrumental record such information has been largely based on historical accounts and trench studies. Written records provide evidence for damages and fatalities, yet are difficult to interpret when derived from the far-field. Trench studies, in turn, offer information on rupture histories, lengths and displacements along faults but involve high chronological uncertainties and fail to record earthquakes that do not rupture the surface. Thus, additional and independent information is required for developing reliable earthquake histories. Here, we present exceptionally well-dated evidence of catastrophic valley infill in the Pokhara Valley, Nepal. Bayesian calibration of radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments yields a robust age distribution that matches the timing of nearby M>8 earthquakes in ~1100, 1255, and 1344 AD. The upstream dip of tributary valley fills and X-ray fluorescence spectrometry of their provenance rule out local sediment sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from the Annapurna Massif >60 km away. The landscape-changing consequences of past large Himalayan earthquakes have so far been elusive. Catastrophic aggradation in the wake of two historically documented medieval earthquakes and one inferred from trench studies underscores that Himalayan valley fills should be considered as potential archives of past earthquakes. Such valley fills are pervasive in the Lesser Himalaya though high erosion rates reduce

Orbital and spin effects for the upper critical field in As-deficient disordered Fe pnictide superconductors

International Nuclear Information System (INIS)

Fuchs, G; Drechsler, S-L; Kozlova, N; Hamann-Borrero, J E; Behr, G; Nenkov, K; Freudenberger, J; Koehler, A; Knupfer, M; Buechner, B; Schultz, L; Bartkowiak, M; Klauss, H-H; Maeter, H; Kwadrin, A; Amato, A; Luetkens, H; Khasanov, R; Arushanov, E; Rosner, H

2009-01-01

We report upper critical field B c2 (T) data for LaO 0.9 F 0.1 FeAs 1-δ in a wide temperature and field range up to 60 T. The large slope of B c2 ∼- 5.4 to -6.6 T K -1 near an improved T c ∼28.5 K of the in-plane B c2 (T) contrasts with a flattening starting near 23 K above 30 T we regard as the onset of Pauli-limited behaviour (PLB) with B c2 (0)∼63-68 T. We interpret a similar hitherto unexplained flattening of the B c2 (T) curves reported for at least three other disordered closely related systems, Co-doped BaFe 2 As 2 , (Ba,K) Fe 2 As 2 and NdO 0.7 F 0.3 FeAs (all single crystals), for applied fields H parallel (a,b), also as a manifestation of PLB. Their Maki parameters have been estimated by analysing their B c2 (T) data within the Werthamer-Helfand-Hohenberg approach. The pronounced PLB of (Ba, K)Fe 2 As 2 single crystals obtained from an Sn flux is attributed also to a significant As deficiency detected by wavelength dispersive x-ray spectroscopy as reported by Ni et al (2008 Phys. Rev. B 78 014507). Consequences of our results are discussed in terms of disorder effects within conventional superconductivity (CSC) and unconventional superconductivity (USC). USC scenarios with nodes on individual Fermi surface sheets (FSS), e.g. p- and d-wave SC, can be discarded for our samples. The increase of dB c2 /dT| T c by sizeable disorder provides evidence for an important intraband (intra-FSS) contribution to the orbital upper critical field. We suggest that it can be ascribed either to an impurity-driven transition from s ± USC to CSC of an extended s ++ -wave state or to a stabilized s ± -state provided As-vacancies cause predominantly strong intraband scattering in the unitary limit. We compare our results with B c2 data from the literature, which often show no PLB for fields below 60-70 T probed so far. A novel disorder-related scenario of a complex interplay of SC with two different competing magnetic instabilities is suggested.

An example of Alaknanda valley, Garhwal Himalaya, India

Indian Academy of Sciences (India)

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

Upper critical field and vortices in S/F bilayers exhibiting the quasi-onedimensional FFLO-like state

Energy Technology Data Exchange (ETDEWEB)

Lenk, Daniel; Hemmida, Mamoun; Kehrle, Jan; Zdravkov, Vladimir I.; Ullrich, Aladin; Obermeier, Guenther; Mueller, Claus; Loidl, Alois; Krug von Nidda, Hans-Albrecht; Horn, Siegfried; Tidecks, Reinhard [Institut fuer Physik, Universitaet Augsburg (Germany); Morari, Roman [Institut fuer Physik, Universitaet Augsburg (Germany); D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Sidorenko, Anatolie S. [D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Tagirov, Lenar [Institut fuer Physik, Universitaet Augsburg (Germany); Solid State Physics Department, Kazan Federal University (Russian Federation)

2015-07-01

We investigate the temperature dependence of the upper critical field, B{sub c2}, in superconductor/ferromagnet (S/F) bilayers as a function of the F-layer thickness, d{sub F}, by resistance measurements. We extracted GL coherence lengths and estimated an effective thickness of the superconducting layer by evaluating the perpendicular coherence length at the 3D-2D crossover temperature in the parallel B{sub c2}. We found an unexpected non-monotonous behavior of the effective thickness as a function of d{sub F}. Moreover, we investigated the anisotropy of B{sub c2} by microwave absorption. The results show a deviation from Tinkham's prediction for thin films, which we attribute to the additional anisotropy induced by the quasi-1D FFLO-like state. Thus, we propose a new type of vortex, developing in the S/F bilayer in magnetic fields applied close to parallel.

Application of field methods to assess isometamidium resistance of trypanosomes in cattle in western Ethiopia

DEFF Research Database (Denmark)

Tewelde, N.; Abebe, G.; Eisler, M.

2004-01-01

This study assessed the degree of isometamidium resistance of trypanosomes infecting cattle in the upper Didessa valley of western Ethiopia. An initial prevalence study was conducted to identify sites with a high risk of trypanosmosis in cattle. The trypanosome prevalence varied widely, with two...

Hydrology of Alkali Creek and Castle Valley Ridge coal-lease tracts, central Utah, and potential effects of coal mining

Science.gov (United States)

Seiler, R.L.; Baskin, R.L.

1988-01-01

The Alkali Creek coal-lease tract includes about 2,150 acres in the Book Cliffs coal field in central Utah, and the Castle Valley Ridge coal-lease tract includes about 3,360 acres in the Wasatch Plateau coal field, also in central Utah. Both the Alkali Creek and Castle Valley Ridge coal-lease tracts are near areas where coal is currently (1987) mined by underground methods from the Cretaceous Blackhawk Formation. The Alkali Creek and Castle Valley Ridge areas have intermittent streams in which flow after snowmelt runoff is locally sustained into midsummer by springflow. The only perennial stream is South Fork Corner Canyon Creek in the Castle Valley Ridge area. Peak flow in both areas generally is from snowmelt runoff; however, peak flow from thunderstorm runoff in the Alkali Creek area can exceed that from snowmelt runoff. Estimated annual source-area sediment yield was 0.5 acre-ft/sq mi in the Alkali Creek lease tract and it was 0.3 acre-ft/sq mi in the Castle Valley Ridge lease tract. Groundwater in the Alkali Creek area occurs in perched aquifers in the Flagstaff Limestone and in other formations above the coal-bearing Blackhawk Formation. The principal source of recharge to the aquifers is snowmelt on outcrops. Faults may be major conduits and control the movement of groundwater. Groundwater discharges at formation contacts, between zones of differing permeability within a formation, near faults and into mines. Water sampled from 13 springs in the Alkali Creek area contained dissolved solids at concentrations ranging from 273 to 5,210 mg/L. Water sampled from 17 springs in the Castle Valley Ridge area contained dissolved solids at concentrations ranging from 208 to 579 mg/L. The composition of water from a recently abandoned part of an active mine the Wasatch Plateau closely resembles that of water discharging from a nearby mine that has been abandoned for more than 30 years. Mining of the Alkali Creek and Castle Valley Ridge coal-lease tracts likely will

A multimethodological approach to study the spatial distribution of air pollution in an Alpine valley during wintertime

Directory of Open Access Journals (Sweden)

R. Schnitzhofer

2009-05-01

Full Text Available In order to investigate the spatial distribution of air pollutants in the Inn valley (Tyrol, Austria during wintertime, a joint field campaign of the three research projects ALPNAP (Monitoring and Minimisation of Traffic-Induced Noise and Air Pollution Along Major Alpine Transport Routes, INNAP (Boundary Layer Structure in the Inn Valley during high Air Pollution and INNOX (NO_x-structure in the Inn Valley during High Air Pollution was carried out in January/February 2006. In addition to continuous ground based measurements, vertical profiles of various air pollutants and meteorological parameters were obtained on six selected days. For in-situ investigations, a tethered balloon was used to analyse the lowest atmospheric layers, 0–500 m above the valley bottom (a.v.b., and a research aircraft sampled at 150–2200 m a.v.b. An aircraft equipped with an aerosol backscatter lidar performed nadir measurements at 3000 m a.v.b. Combined results from a typical day show a strongly polluted layer up to about 125 m a.v.b. in the morning. Around midday concentrations on the valley floor decrease indicating some vertical air exchange despite thermally stable conditions. Strong vertical and horizontal gradients with enhanced pollution levels along the sunny side of the valley up to 1300 m a.v.b. were observed in the afternoon. This vertical mixing due to thermally or dynamically driven slope winds reduces the concentration of air pollutants at the bottom of the valley and causes the formation of elevated pollution layers.

California's restless giant: the Long Valley Caldera

Science.gov (United States)

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

2014-01-01

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

A Field Test for Upper Body Strength and Endurance.

Science.gov (United States)

Nelson, Jack K.; And Others

1991-01-01

Researchers studied the reliability of the modified push-up test in measuring upper body strength and endurance in elementary through college students. It also examined the accuracy of partner scoring. The test proved much easier to administer than the regular floor push-up. It was valid and reliable for all students and suitable for partner…

Inspecting the transformation of Roman settlements in the Upper Potenza Valley (Marche region across Late Antiquity and into the Early Medieval era

Directory of Open Access Journals (Sweden)

Francesca Carboni

2015-12-01

Full Text Available The following analysis shows the changes occurred in the settlement patterns in the upper Potenza river valley (MC, Marche region during the transition period between Late Antiquity and Early Middle Ages. This analysis is mainly based on the results of a geoarchaeological project, which has been carried out by a team from Ghent University since 2000. The review of the pottery collected during the fi eld survey has allowed for a better defined chronology of the last phase of occupation of the rural sites identifi ed in the sample zone, located within an intermediate basin between the Umbria-Marche Apennines and a lateral dorsal ridge, in areas dominated by the hilltops of Monte Primo and Monte Castel Santa Maria. For some of these sites, it is now possible to ascertain a continuity of life up to the end of the seventh century and further into the Middle Ages. La presente analisi illustra le trasformazioni delle modalità insediative avvenute nel periodo di transizione fra la tarda antichità e il medioevo nell’alta valle del fi ume Potenza (MC, Marche. Essa si basa sui risultati del progetto condotto con metodo geo-archeologico da un gruppo di ricerca dell’Università di Ghent, dal 2000. La revisione del materiale ceramico raccolto nel corso delle ricognizioni ha consentito di defi nire meglio le ultime fasi di occupazione dei siti rurali identifi cati nella zona campione in questione, posizionata all’interno del bacino intramontano posto fra l’Appennino umbro-marchigiano e una dorsale montuosa laterale, dominata dalle cime del Monte Primo e del Monte Santa Maria. Per alcuni di questi siti è stato, infatti, possibile accertare una continuità di occupazione estesa fi no al VII secolo e oltre, in età medievale.

Valley Fever

Science.gov (United States)

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

Coho Salmon Habitat in a Changing Environment-Green Valley Creek, Graton, California

Science.gov (United States)

O'Connor, M. D.; Kobor, J. S.; Sherwood, M. N.

2013-12-01

Green Valley Creek (GVC) is a small (101 sq km) aquatic habitat refugium in the Russian River watershed (3,840 sq km) in coastal northern California. Coho salmon (Onchorhynchus kisutch) is endangered per the Federal Endangered Species Act, and GVC is one stream where coho have persisted. Fish surveys in GVC have found high species diversity, growth rates, and over-summer survival. The upper portion of GVC comprises a principal tributary (20 sq km) that provides spawning and rearing habitat for coho. The second principal tributary, Atascadero Creek, is comparable in size, but has few fish. Atascadero Creek and lower GVC have broad, densely vegetated floodplains. A Recovery Plan for the Central Coastal California coho Evolutionarily Significant Unit has been developed by the National Marine Fisheries Service (NMFS), which applies to the Russian River and its tributaries. Cooperative research regarding fish populations and habitat, a captive breeding and release program for native coho salmon, and efforts to plan for and restore habitat are ongoing. These regional efforts are particularly active in GVC, and participants include NMFS, the California Department of Fish and Wildlife, the Gold Ridge Resource Conservation District, the California Coastal Conservancy, the University of California Cooperative Extension, and the National Fish and Wildlife Foundation, among others. Our research focuses on hydrologic, geomorphic and hydrogeologic characteristics of the watershed in relation to aquatic habitat. Natural watershed factors contributing to habitat for coho include proximity to the coastal summer fog belt with cool temperatures, the Wilson Grove Formation aquifer that maintains dry season stream flow, and structural geology favorable for active floodplain morphology. Human impacts include water use and agriculture and rural residential development. Historic human impacts include stream clearing and draining of wetlands and floodplain for agriculture, which likely

NNSS Soils Monitoring: Plutonium Valley (CAU 366) FY2015

Energy Technology Data Exchange (ETDEWEB)

Nikolich, George [Desert Research Inst. (DRI), Las Vegas, NV (United States); Mizell, Steve [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg [Desert Research Inst. (DRI), Reno, NV (United States); Campbell, Scott [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

2017-02-01

Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil transport from the Plutonium Valley Contamination Area (CA) as a result of wind transport and storm runoff in support of National Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the contamination areas. The DRI work is intended to confirm the likely mechanism(s) of transport and determine the meteorological conditions that might cause movement of contaminated soils. The emphasis of the work is on collecting sediment transported by channelized storm runoff at the Plutonium Valley investigation sites. These data will inform closure plans that are being developed, which will facilitate the appropriate closure design and post-closure monitoring. In 2011, DRI installed two meteorological monitoring stations south (station #1) and north (station #2) of the Plutonium Valley CA and a runoff sediment sampling station within the CA. Temperature, wind speed, wind direction, relative humidity, precipitation, solar radiation, barometric pressure, soil temperature, and airborne particulate concentration are collected at both meteorological stations. The maximum, minimum, and average or total (as appropriate) for each of these parameters are recorded for each 10-minute interval. The sediment sampling station includes an automatically activated ISCO sampling pump with collection bottles for suspended sediment, which is activated when sufficient flow is present in the channel, and passive traps for bedload material that is transported down the channel during runoff events. This report presents data collected from these stations during fiscal year (FY) 2015.

Nematic and Valley Ordering in Anisotropic Quantum Hall Systems

Science.gov (United States)

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

2010-03-01

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

Resistivity structure and geochemistry of the Jigokudani Valley hydrothermal system, Mt. Tateyama, Japan

Science.gov (United States)

Seki, Kaori; Kanda, Wataru; Tanbo, Toshiya; Ohba, Takeshi; Ogawa, Yasuo; Takakura, Shinichi; Nogami, Kenji; Ushioda, Masashi; Suzuki, Atsushi; Saito, Zenshiro; Matsunaga, Yasuo

2016-10-01

This study clarifies the hydrothermal system of Jigokudani Valley near Mt. Tateyama volcano in Japan by using a combination of audio-frequency magnetotelluric (AMT) survey and hot-spring water analysis in order to assess the potential of future phreatic eruptions in the area. Repeated phreatic eruptions in the area about 40,000 years ago produced the current valley morphology, which is now an active solfatara field dotted with hot springs and fumaroles indicative of a well-developed hydrothermal system. The three-dimensional (3D) resistivity structure of the hydrothermal system was modeled by using the results of an AMT survey conducted at 25 locations across the valley in 2013-2014. The model suggests the presence of a near-surface highly conductive layer of falling largely on a mixing line between magmatic fluids and local meteoric water (LMW). The geochemical analysis suggests that the hydrothermal system includes a two-phase zone of vapor-liquid. A comparison of the resistivity structure and the geochemically inferred structure suggests that a hydrothermal reservoir is present at a depth of approximately 500 m, from which hot-spring water differentiates into the three observed types. The two-phase zone appears to be located immediately beneath the cap rock structure. These findings suggest that the hydrothermal system of Jigokudani Valley exhibits a number of factors that could trigger a future phreatic eruption.

Ballistic electron transport calculation of strained germanium-tin fin field-effect transistors

Energy Technology Data Exchange (ETDEWEB)

Lan, H.-S. [Graduate Institute of Electronics Engineering and Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Liu, C. W., E-mail: chee@cc.ee.ntu.edu.tw [Graduate Institute of Electronics Engineering and Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China)

2014-05-12

The dependence of ballistic electron current on Sn content, sidewall orientations, fin width, and uniaxial stress is theoretically studied for the GeSn fin field-effect transistors. Alloying Sn increases the direct Γ valley occupancy and enhances the injection velocity at virtual source node. (112{sup ¯}) sidewall gives the highest current enhancement due to the rapidly increasing Γ valley occupancy. The non-parabolicity of the Γ valley affects the occupancy significantly. However, uniaxial tensile stress and the shrinkage of fin width reduce the Γ valley occupancy, and the currents are enhanced by increasing occupancy of specific indirect L valleys with high injection velocity.

Dimensional Crossover and Its Interplay with In-Plane Anisotropy of Upper Critical Field in β-(BDA-TTP)2SbF6

Science.gov (United States)

Yasuzuka, Syuma; Koga, Hiroaki; Yamamura, Yasuhisa; Saito, Kazuya; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Yamada, Jun-ichi

2017-08-01

Resistance measurements have been performed to investigate the dimensionality and the in-plane anisotropy of the upper critical field (Hc2) for β-(BDA-TTP)2SbF6 in fields H up to 15 T and at temperatures T from 1.5 to 7.5 K, where BDA-TTP stands for 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene. The upper critical fields parallel and perpendicular to the conduction layer are determined and dimensional crossover from anisotropic three-dimensional behavior to two-dimensional behavior is found at around 6 K. When the direction of H is varied within the conducting layer at 6.0 K, Hc2 shows twofold symmetry: Hc2 along the minimum Fermi wave vector (maximum Fermi velocity) is larger than that along the maximum Fermi wave vector (minimum Fermi velocity). The normal-state magnetoresistance has twofold symmetry similar to Hc2 and shows a maximum when the magnetic field is nearly parallel to the maximum Fermi wave vector. This tendency is consistent with the Fermi surface anisotropy. At 3.5 K, we found clear fourfold symmetry of Hc2 despite the fact that the normal-state magnetoresistance shows twofold symmetry arising from the Fermi surface anisotropy. The origin of the fourfold symmetry of Hc2 is discussed in terms of the superconducting gap structure in β-(BDA-TTP)2SbF6.

Dimensional crossover and its interplay with in-plane anisotropy of upper critical field in β-(BDA-TTP)_2SbF_6

International Nuclear Information System (INIS)

Yasuzuka, Syuma; Koga, Hiroaki; Yamamura, Yasuhisa; Saito, Kazuya; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Yamada, Jun-ichi

2017-01-01

Resistance measurements have been performed to investigate the dimensionality and the in-plane anisotropy of the upper critical field (H_c_2) for β-(BDA-TTP)_2SbF_6 in fields H up to 15 T and at temperatures T from 1.5 to 7.5 K, where BDA-TTP stands for 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene. The upper critical fields parallel and perpendicular to the conduction layer are determined and dimensional crossover from anisotropic three-dimensional behavior to two-dimensional behavior is found at around 6 K. When the direction of H is varied within the conducting layer at 6.0 K, H_c_2 shows twofold symmetry: H_c_2 along the minimum Fermi wave vector (maximum Fermi velocity) is larger than that along the maximum Fermi wave vector (minimum Fermi velocity). The normal-state magnetoresistance has twofold symmetry similar to H_c_2 and shows a maximum when the magnetic field is nearly parallel to the maximum Fermi wave vector. This tendency is consistent with the Fermi surface anisotropy. At 3.5 K, we found clear fourfold symmetry of H_c_2 despite the fact that the normal-state magnetoresistance shows twofold symmetry arising from the Fermi surface anisotropy. The origin of the fourfold symmetry of H_c_2 is discussed in terms of the superconducting gap structure in β-(BDA-TTP)_2SbF_6. (author)

Revisions to the original extent of the Devonian Shale-Middle and Upper Paleozoic Total Petroleum System

Science.gov (United States)

Enomoto, Catherine B.; Rouse, William A.; Trippi, Michael H.; Higley, Debra K.

2016-04-11

Technically recoverable undiscovered hydrocarbon resources in continuous accumulations are present in Upper Devonian and Lower Mississippian strata in the Appalachian Basin Petroleum Province. The province includes parts of New York, Pennsylvania, Ohio, Maryland, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama. The Upper Devonian and Lower Mississippian strata are part of the previously defined Devonian Shale-Middle and Upper Paleozoic Total Petroleum System (TPS) that extends from New York to Tennessee. This publication presents a revision to the extent of the Devonian Shale-Middle and Upper Paleozoic TPS. The most significant modification to the maximum extent of the Devonian Shale-Middle and Upper Paleozoic TPS is to the south and southwest, adding areas in Tennessee, Georgia, Alabama, and Mississippi where Devonian strata, including potential petroleum source rocks, are present in the subsurface up to the outcrop. The Middle to Upper Devonian Chattanooga Shale extends from southeastern Kentucky to Alabama and eastern Mississippi. Production from Devonian shale has been established in the Appalachian fold and thrust belt of northeastern Alabama. Exploratory drilling has encountered Middle to Upper Devonian strata containing organic-rich shale in west-central Alabama. The areas added to the TPS are located in the Valley and Ridge, Interior Low Plateaus, and Appalachian Plateaus physiographic provinces, including the portion of the Appalachian fold and thrust belt buried beneath Cretaceous and younger sediments that were deposited on the U.S. Gulf Coastal Plain.

Deformation of ``Villafranchian'' lacustrine sediments in the Chisone Valley (Western Alps, Italy)

Science.gov (United States)

Collo, Giovanni; Giardino, Marco

1997-09-01

The Chisone Valley is located in the internal NW Alps, in the Pinerolese District, an area characterized by present low to medium seismicity. Fine-grained sediments (sand, silt and clay with interbedded gravel) crop out in the lower Chisone Valley: they were first interpreted as glaciolacustrine deposits, and then as a lacustrine infilling of the valley floor probably due to differential uplifting of the valley mouth. Review of this data, together with new field and palynological observations, lead us to refer the lacustrine deposits to approximately the Lower Pleistocene (Villafranchian). In many outcrops, the lacustrine deposits show strong soft-sediment deformation such as convolute laminations, water-escape structures and disrupted beds, some of them associated with folds and faults (cm to dm in size); only two sites show metric to decametric folds and faults trending E-W and N-S. Detailed structural analysis conducted along a recently exposed section (Rio Gran Dubbione site) shows several soft-sediment deformation features on the limbs of mesoscale folds. Because of their intimate structural association, the origin of these minor structures seems to be connected to synsedimentary activity on reverse and normal faults (m to dm in size) affecting the lacustrine deposits in the same locality. Soft-sediment deformation features can be interpreted as possible paleoseismites. If so, the present seismicity of the Pinerolese District, which is the major area of such activity in NW Italy, cannot be considered an isolated episode in the geological evolution of the region; even if there is no supporting evidence for continuous seismicity, the deformations in the lacustrine sediments of the Chisone Valley testify to Early Pleistocene seismic activity, probably related to the recent tectonic evolution of the internal side of the NW Alps.

The geological model calibration - Learnings from integration of reservoir geology and field performance - Example from the upper carboniferous reservoirs of the Southern North Sea

NARCIS (Netherlands)

Moscariello, A.; Hoof, T.B. van; Kunakbayeva, G.; Veen, J.H. ten; Belt, F. van den; Twerda, A.; Peters, L.; Davis, P.; Williams, H.

2013-01-01

The Geological Model Calibration - Learnings from Integration of Reservoir Geology and Field Performance: example from the Upper Carboniferous Reservoirs of the Southern North Sea. Copyright © (2012) by the European Association of Geoscientists & Engineers All rights reserved.

Volume pinning force and upper critical field of irradiated Nb3Sn

International Nuclear Information System (INIS)

Maier, P.; Seibt, E.

1981-01-01

Irradiation by neutrons and ions in A15 superconductors (Nb 3 Sn, V 3 Ga) exerts a stronger influence on the pinning behavior than in nonordered alloys (NbTi). In this work it is shown for deuteron irradiated Nb 3 /Sn wires prepared by the bronze process that the dose curve of the volume pinning force P/sub V/ can be conveniently described by a sum of two terms, due to the grain boundary pinning and to the radiation pinning, respectively. After deduction of the contribution by the radiation-induced pinning centers, good agreement is obtained between the measured P/sub V/ values and those calculated using the upper critical field B/sub c/2 and the transition temperature T/sub c/ on the basis of the irradiation fluence. The use of a theoretical relationship between B/sub c/2 and T/sub c/ is supported by measured values. Application to multifilamentary superconductors with high current carrying capabilities simplifies the calculation of P/sub V/, since the radiation induced volume pinning force can be neglected

Middle Palaeolithic toolstone procurement behaviors at Lusakert Cave 1, Hrazdan valley, Armenia.

Science.gov (United States)

Frahm, Ellery; Feinberg, Joshua M; Schmidt-Magee, Beverly A; Wilkinson, Keith N; Gasparyan, Boris; Yeritsyan, Benik; Adler, Daniel S

2016-02-01

Strategies employed by Middle Palaeolithic hominins to acquire lithic raw materials often play key roles in assessing their movements through the landscape, relationships with neighboring groups, and cognitive abilities. It has been argued that a dependence on local resources is a widespread characteristic of the Middle Palaeolithic, but how such behaviors were manifested on the landscape remains unclear. Does an abundance of local toolstone reflect frequent encounters with different outcrops while foraging, or was a particular outcrop favored and preferentially quarried? This study examines such behaviors at a finer geospatial scale than is usually possible, allowing us to investigate hominin movements through the landscape surrounding Lusakert Cave 1 in Armenia. Using our newly developed approach to obsidian magnetic characterization, we test a series of hypotheses regarding the locations where hominins procured toolstone from a volcanic complex adjacent to the site. Our goal is to establish whether the cave's occupants procured local obsidian from preferred outcrops or quarries, secondary deposits of obsidian nodules along a river, or a variety of exposures as encountered while moving through the river valley or across the wider volcanic landscape during the course of foraging activities. As we demonstrate here, it is not the case that one particular outcrop or deposit attracted the cave occupants during the studied time intervals. Nor did they acquire obsidian at random across the landscape. Instead, our analyses support the hypothesis that these hominins collected obsidian from outcrops and exposures throughout the adjacent river valley, reflecting the spatial scale of their day-to-day foraging activities. The coincidence of such behaviors within the resource-rich river valley suggests efficient exploitation of a diverse biome during a time interval immediately preceding the Middle to Upper Palaeolithic "transition," the nature and timing of which has yet to

Rashba effect and enriched spin-valley coupling in Ga X /M X2 (M = Mo, W; X = S, Se, Te) heterostructures

Science.gov (United States)

Zhang, Qingyun; Schwingenschlögl, Udo

2018-04-01

Using first-principles calculations, we investigate the electronic properties of the two-dimensional Ga X /MX 2 (M = Mo, W; X = S, Se, Te) heterostructures. Orbital hybridization between Ga X and MX 2 is found to result in Rashba splitting at the valence-band edge around the Γ point, which grows for increasing strength of the spin-orbit coupling in the p orbitals of the chalcogenide atoms. The location of the valence-band maximum in the Brillouin zone can be tuned by strain and application of an out-of-plane electric field. The coexistence of Rashba splitting (in-plane spin direction) and band splitting at the K and K' valleys (out-of-plane spin direction) makes Ga X /MX 2 heterostructures interesting for spintronics and valleytronics. They are promising candidates for two-dimensional spin-field-effect transistors and spin-valley Hall effect devices. Our findings shed light on the spin-valley coupling in van der Waals heterostructures.

Geochemical tracing and hydrogeochemical modelling of water-rock interactions during salinization of alluvial groundwater (Upper Rhine Valley, France)

Energy Technology Data Exchange (ETDEWEB)

Lucas, Y., E-mail: yann.lucas@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Schmitt, A.D., E-mail: anne-desiree.schmitt@univ-fcomte.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)] [Universite de Franche-Comte et CNRS-UMR 6249, Chrono-Environnement, 16, Route de Gray, 25030 Besancon Cedex (France); Chabaux, F., E-mail: francois.chabaux@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Clement, A.; Fritz, B. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Elsass, Ph. [BRGM, GEODERIS, 1, rue Claude Chappe, 57070 Metz (France); Durand, S. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)

2010-11-15

Research highlights: {yields} Major and trace elements along with strontium and uranium isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect a conservative mixing. {yields} A coupled hydrogeochemical model demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process. {yields} The model requires only a small amount of montmorillonite. {yields} It is necessary to consider the pollution history to explain the important chloride, sodium and calcium concentration modifications. {yields} The model shows that the rapidity of the cationic exchange reactions insures a reversibility of the cation fixation on clays in the aquifer. - Abstract: In the southern Upper Rhine Valley, groundwater has undergone intensive saline pollution caused by the infiltration of mining brines, a consequence of potash extraction carried out during the 20th century. Major and trace elements along with Sr and U isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect conservative mixing between saline waters resulting from the dissolution of waste heaps and one or more unpolluted end-members. The results imply the occurrence of interactions between host rocks and polluted waters, and they suggest that cationic exchange mechanisms are the primary controlling process. A coupled hydrogeochemical model has been developed with the numerical code KIRMAT, which demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process controlling the geochemical evolution of the groundwater. The model requires only a small amount of montmorillonite (between 0.75% and 2.25%), which is in agreement with the observed mineralogical composition of the aquifer. The model also proves

Disorder-dependent valley properties in monolayer WSe2

KAUST Repository

Tran, Kha

2017-07-19

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

Peak-to-valley ratios for three different HPGe detectors for the assessment of 137Cs deposition on the ground and the impact of the detector field-of-view.

Science.gov (United States)

Östlund, Karl; Samuelsson, Christer; Mattsson, Sören; Rääf, Christopher L

2017-02-01

The peak-to-valley (PTV) method was investigated experimentally comparing PTV ratios for three HPGe detectors, with complementary Monte Carlo simulations of scatter in air for larger source-detector distances. The measured PTV ratios for 137Cs in air were similar for three different detectors for incident angles between 0 and 90°. The study indicated that the PTV method can differentiate between surface and shallow depth sources if the detector field of view is limited to a radius of less than 3.5m. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-12-01

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

Prevalence and distribution of pox-like lesions, avian malaria, and mosquito vectors in Kipahulu valley, Haleakala National Park, Hawai'i, USA

Science.gov (United States)

Aruch, Samuel; Atkinson, Carter T.; Savage, Amy F.; LaPointe, Dennis

2007-01-01

We determined prevalence and altitudinal distribution of introduced avian malarial infections (Plasmodium relictum) and pox-like lesions (Avipoxvirus) in forest birds from Kīpahulu Valley, Haleakalā National Park, on the island of Maui, and we identified primary larval habitat for the mosquito vector of this disease. This intensively managed wilderness area and scientific reserve is one of the most pristine areas of native forest remaining in the state of Hawai‘i, and it will become increasingly important as a site for restoration and recovery of endangered forest birds. Overall prevalence of malarial infections in the valley was 8% (11/133) in native species and 4% (4/101) in nonnative passerines; prevalence was lower than reported for comparable elevations and habitats elsewhere in the state. Infections occurred primarily in ‘Apapane (Himatione sanguinea) and Hawai‘i ‘Amakihi (Hemignathus virens) at elevations below 1,400 m. Pox-like lesions were detected in only two Hawai‘i ‘Amakihi (2%; 2/94) at elevations below 950 m. We did not detect malaria or pox in birds caught at 1,400 m in upper reaches of the valley. Adult mosquitoes (Culex quinquefasciatus) were captured at four sites at elevations of 640, 760, 915, and 975 m, respectively. Culex quinquefasciatus larvae were found only in rock holes along intermittent tributaries of the two largest streams in the valley, but not in standing surface water, pig wallows, ground pools, tree cavities, and tree fern cavities. Mosquito populations in the valley are low, and they are probably influenced by periods of high rainfall that flush stream systems.

Reversal of the Upper Critical Field Anisotropy and Spin-Locked Superconductivity in K2Cr3As3

International Nuclear Information System (INIS)

Balakirev, Fedor Fedorovich; Kong, T.; Jaime, Marcelo; McDonald, Ross David; Mielke, Charles H.; Gurevich, A.; Canfield, P. C.; Bud'ko, S. L.

2016-01-01

Recently, superconductivity in K 2 Cr 3 As 3 (T c =6.1 K) was discovered. The crystalline lattice contains an array of weakly coupled, double well [(Cr 3 As 3 ) 2- ] ∞ linkages stretched along the c axis, suggesting the possibility of quasi-one-dimensional superconductivity. Moderately anisotropic upper critical field was revealed in single crystals, with very large initial slopes, dH || c2 /dT=12 T/K along the Cr chains and dH perpendicular c2 /dT =7 T/K perpendicular to the chains. Given the ambiguity of conclusions based on the extrapolations of H c2 (T) measured near T c to low temperatures, we performed high-field measurements of H c2 (T) on K 2 Cr 3 As 3 single crystals in pulsed magnetic fields which enabled us to reveal the full anisotropic H c2 (T) curves from T c down to 600 mK.

Resource Limitations on Soil Microbial Activity in an Antarctic Dry Valley

DEFF Research Database (Denmark)

Sparrow, Asley; Gregorich, Ed; Hopkins, David

2011-01-01

Although Antarctic dry valley soils function under some of the harshest environmental conditions on the planet, there is significant biological activity concentrated in small areas in the landscape. These productive areas serve as a source of C and N in organic matter redistributed...... to the surrounding biologically impoverished soils. We conducted a 3-yr replicated field experiment involving soil amendment with C and N in simple (glucose and NH4Cl) and complex (glycine and lacustrine detritus) forms to evaluate the resource limitations on soil microbial activity in an Antarctic dry valley....... The respiratory response for all substrates was slow, with a significant but weak response to NH4Cl, followed by a more widespread response to all substrates after 2 yr and in laboratory incubations conducted 3 yr after substrate addition. This response suggests that the soil microbial community is N limited and...

Antifan activism as a response to MTV's The Valleys

Directory of Open Access Journals (Sweden)

Bethan Jones

2015-06-01

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

Interpretation of shallow crustal structure of the Imperial Valley, California, from seismic reflection profiles

Energy Technology Data Exchange (ETDEWEB)

Severson, L.K.

1987-05-01

Eight seismic reflection profiles (285 km total length) from the Imperial Valley, California, were provided to CALCRUST for reprocessing and interpretation. Two profiles were located along the western margin of the valley, five profiles were situated along the eastern margin and one traversed the deepest portion of the basin. These data reveal that the central basin contains a wedge of highly faulted sediments that thins to the east. Most of the faulting is strike-slip but there is evidence for block rotations on the scale of 5 to 10 kilometers within the Brawley Seismic Zone. These lines provide insight into the nature of the east and west edges of the Imperial Valley. The basement at the northwestern margin of the valley, to the north of the Superstition Hills, has been normal-faulted and blocks of basement material have ''calved'' into the trough. A blanket of sediments has been deposited on this margin. To the south of the Superstition Hills and Superstition Mountain, the top of the basement is a detachment surface that dips gently into the basin. This margin is also covered by a thick sequence sediments. The basement of the eastern margin consists of metamorphic rocks of the upper plate of the Chocolate Mountain Thrust system underlain by the Orocopia Schist. These rocks dip to the southeast and extend westward to the Sand Hills Fault but do not appear to cross it. Thus, the Sand Hills Fault is interpreted to be the southern extension of the San Andreas Fault. North of the Sand Hills Fault the East Highline Canal seismicity lineament is associated with a strike-slip fault and is probably linked to the Sand Hills Fault. Six geothermal areas crossed by these lines, in agreement with previous studies of geothermal reservoirs, are associated with ''faded'' zones, Bouguer gravity and heat flow maxima, and with higher seismic velocities than surrounding terranes.

Is it working? A look at the changing nutrient practices in Oregon's Southern Willamette Valley Groundwater Management Area

Science.gov (United States)

Pearlstein, S.; Compton, J.; Eldridge, A.; Henning, A.; Selker, J. S.; Brooks, J. R.; Schmitz, D.

2016-12-01

Groundwater nitrate contamination affects thousands of households in the southern Willamette Valley and many more across the Pacific Northwest. The southern Willamette Valley Groundwater Management Area (SWV GWMA) was established in 2004 due to nitrate levels in the groundwater exceeding the human health standard of 10 mg nitrate-N L-1. Much of the nitrogen inputs to the GWMA comes from agricultural nitrogen use, and thus efforts to reduce N inputs to groundwater are focused upon improving N management. Previous work in the 1990s in the Willamette Valley by researchers at Oregon State University determined the importance of cover crops and irrigation practices and made recommendations to the local farm community for reducing nitrogen (N) leaching. We are currently re-sampling many of the same fields studied by OSU to examine the influence of current crops and nutrient management practices on nitrate leaching below the rooting zone. This study represents important crops currently grown in the GWMA and includes four grass fields, three vegetable row-crop fields, two peppermint and wheat fields, and one each of hazelnuts and blueberries. New nutrient management practices include slow release fertilizers and precision agriculture approaches in some of the fields. Results from the first two years of sampling show nitrate leaching is lower in some crops like row crops grown for seed and higher in others like perennial rye grass seed when compared to the 1990s data. We will use field-level N input-output balances in order to determine the N use efficiency and compare this across crops and over time. The goal of this project is to provide information and tools that will help farmers, managers and conservation groups quantify the water quality benefits of management practices they are conducting or funding.

The quasi-steady state of the valley wind system

Directory of Open Access Journals (Sweden)

Juerg eSchmidli

2015-12-01

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

Direct measurement of exciton valley coherence in monolayer WSe2

KAUST Repository

Hao, Kai

2016-02-29

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

The Impact of Soil Properties on Valley-Bottom Gully Form, Northwest Highlands of Ethiopia.

Science.gov (United States)

Amare, S. D.; Langendoen, E. J.; Keesstra, S.; van der Ploeg, M. J.; Steenhuis, T. S.; Tilahun, S. A.

2017-12-01

Gully erosion is an important environmental and food security challenge facing the world. Despite the immense damages resulting from gully erosion, comprehensive studies on the processes of gully formation and its management strategies are limited. This is especially true for valley-bottom gullies, which form under different conditions and are caused by different processes than hillslope gullies. A recent review on valley-bottom gully erosion causes and controlling factors identified that gully geomorphological processes, particularly related to gully bank retreat, governed gully occurrence and reclamations. However, most valley-bottom gully erosion studies do not consider gully bank stability and how it is impacted by soil hydrology and soil intrinsic properties. The aim is to analyze these impacts on gully bank retreat in the Koga river watershed, Ethiopia, for Nitisol and Vertisols, using field and numerical modeling approaches. Field observations showed gully network in Vertisols were greater than those in Nitisols. On the other hand, Nitisol gullies are wider and deeper than Vertisols. Monitoring of hydro-meteorological and soil data was started in June 2017 and will continue until the end of the 2017 rainy season (September) and for 2018 rainy periods as well. Thirty-six piezometers were installed at 4m average depth covering an area of 20 km2 near the gully reaches. Ground anchors were used to measure soil swelling and shrinkage. Soil moisture content and potential were measured using GS1 Soil Moisture sensors and MPS-6 Water Potential sensors. Gully bank soil physicochemical and engineering properties have been sampled and analyzed. Preliminary results from the early portion of the rainy season showed that most piezometers were already filled up with water. However, relatively deep (2m) water tables were recorded in piezometers located near the gully banks. The soil matric potential dropped from the onset of the rainy season (-6800 kPa ) towards the middle

Spin-valley splitting of electron beam in graphene

Directory of Open Access Journals (Sweden)

Yu Song

2016-11-01

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

Strategic Location and Territorial Integrity: The Role of Subsidiary Sites in the Classic Maya Kingdoms of the Upper Usumacinta Region

Directory of Open Access Journals (Sweden)

Armando Anaya Hernández

2006-03-01

archaeological and epigraphic data. Regarding the latter, the hieroglyphic inscriptions record a couple of devastating attacks that Piedras Negras launched upon Pomoná in AD 792 and 794. I argue on the basis of the characteristics of the physical landscape and the territory controlled by each of these polities that, in order to carry out a successful campaign, Piedras Negras must have exercised control of one of the few natural passes that separate the coastal plains, where Pomoná lies, from the remainder of the Upper Usumacinta region, where Piedras Negras is located. One of these passes lies in the Redención del Campesino Valley; however, no subsidiary site of significance was known to exist in this valley. In this sense our 2004-2005 archaeological reconnaissance of the valley was geared to search for a site of this nature. Once again taking advantage of the spatial modelling capabilities of GIS, a probability model based on Dempster-Shafer Theory was designed to identify the areas of high potential where the presence of this type of site may occur. The probability model was tested in the field and a site located that, due to its monumental architecture, could be characterised as a subsidiary site of high strategic and political relevance.

Valley polarized quantum Hall effect and topological insulator phase transitions in silicene

KAUST Repository

Tahir, M.

2013-01-25

The electronic properties of silicene are distinct from both the conventional two dimensional electron gas and the famous graphene due to strong spin orbit interaction and the buckled structure. Silicene has the potential to overcome limitations encountered for graphene, in particular the zero band gap and weak spin orbit interaction. We demonstrate a valley polarized quantum Hall effect and topological insulator phase transitions. We use the Kubo formalism to discuss the Hall conductivity and address the longitudinal conductivity for elastic impurity scattering in the first Born approximation. We show that the combination of an electric field with intrinsic spin orbit interaction leads to quantum phase transitions at the charge neutrality point, providing a tool to experimentally tune the topological state. Silicene constitutes a model system for exploring the spin and valley physics not accessible in graphene due to the small spin orbit interaction.

Transient Electromagnetic Soundings Near Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado (2006 Field Season)

Science.gov (United States)

Fitterman, David V.; de Sozua Filho, Oderson A.

2009-01-01

Time-domain electromagnetic (TEM) soundings were made near Great Sand Dunes National Park and Preserve in the San Luis Valley of southern Colorado to obtain subsurface information of use to hydrologic modeling. Seventeen soundings were made to the east and north of the sand dunes. Using a small loop TEM system, maximum exploration depths of about 75 to 150 m were obtained. In general, layered earth interpretations of the data found that resistivity decreases with depth. Comparison of soundings with geologic logs from nearby wells found that zones logged as having increased clay content usually corresponded with a significant resistivity decrease in the TEM determined model. This result supports the use of TEM soundings to map the location of the top of the clay unit deposited at the bottom of the ancient Lake Alamosa that filled the San Luis Valley from Pliocene to middle Pleistocene time.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Science.gov (United States)

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

2015-11-01

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

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

Directory of Open Access Journals (Sweden)

E. Glowacka

2015-11-01

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

Subsidence and Rebound in California's Central Valley: Effects of Pumping, Geology, and Precipitation

Science.gov (United States)

Farr, T. G.; Fairbanks, A.

2017-12-01

Recent rains in California caused a pause, and even a reversal in some areas, of the subsidence that has plagued the Central Valley for decades. The 3 main drivers of surface deformation in the Central Valley are: Subsurface hydro-geology, precipitation and surface water deliveries, and groundwater pumping. While the geology is relatively fixed in time, water inputs and outputs vary greatly both in time and space. And while subsurface geology and water inputs are reasonably well-known, information about groundwater pumping amounts and rates is virtually non-existent in California. We have derived regional maps of surface deformation in the region for the period 2006 - present which allow reconstruction of seasonal and long-term changes. In order to understand the spatial and temporal patterns of subsidence and rebound in the Central Valley, we have been compiling information on the geology and water inputs and have attempted to infer pumping rates using maps of fallowed fields and published pumping information derived from hydrological models. In addition, the spatial and temporal patterns of hydraulic head as measured in wells across the region allow us to infer the spatial and temporal patterns of groundwater pumping and recharge more directly. A better understanding of how different areas (overlying different stratigraphy) of the Central Valley respond to water inputs and outputs will allow a predictive capability, potentially defining sustainable pumping rates related to water inputs. * work performed under contract to NASA and the CA Dept. of Water Resources

Sedimentology of the Upper Maastrichtian chalk, Danish Central Graben. M-10X (Dan Field), E-5X (Tyra SE Field) facies and core logs

Energy Technology Data Exchange (ETDEWEB)

Ineson, J.R.

2004-07-01

Based on detailed logs presented here at 1:10, the cored Upper Maastrichtian succession of the M-10X (Dan Field) and E-5X (Tyra SE Field) wells in the southern Danish Central Graben is subdivided into eight lithofacies and five ichnofabrics. The dominant bioturbated or laminated chalk mudstones and subordinate sparse skeletal wackestones are largely the result of pelagic carbonate production, sedimented by suspension settling and small volume, low density turbidity currents. Evidence of winnowing/reduced sedimentation rates is yielded by rare incipient hardgrounds; a well-developed mature hardground profile is developed at the Cretaceous-Danian boundary (the ''Maastrichtian hardground''). Rare marl laminae are recorded and a discrete marly chalk bed associated with an interval of finegrained skeletal chalk wackestones near the top of the Maastrichtian is recognised in both wells. Comparison between the two wells demonstrates that the m-scale laminated-bioturbated chalk cycles described from the Dan Field area are both stratigraphically and areally restricted; this has implications for both cyclostratigraphic correlation and reconstruction of depositional environments and Late Maastrichtian evolution of the Danish Central Graben. (au)

Yield gaps and resource use across farming zones in the central rift valley of Ethiopia

NARCIS (Netherlands)

Getnet, Mezegebu; Ittersum, van Martin; Hengsdijk, Huib; Descheemaeker, Katrien

2016-01-01

In the Central Rift Valley (CRV) of Ethiopia, low productive cereal systems and a declining resource base call for options to increase crop productivity and improve resource use efficiency to meet the growing demand of food. We compiled and analysed a large amount of data from farmers’ fields

Dendroclimatic Reconstruction of Summer Temperatures in Irik Valley, Mount Elbrus (Greater Caucasus

Directory of Open Access Journals (Sweden)

Iulian Horia HOLOBÂCĂ

2014-11-01

Full Text Available Recent evidence suggests an acceleration of glacier retreat in Greater Caucasus after 1980. For the same period a significant summer temperature warming trend and little or no change in precipitation variation have been observed. In this paper we seek to find similar past climatic conditions using a dendroclimatic reconstruction of summer temperatures from upper treeline sites after the Little Ice Age (LIA. Dendroclimatological sampling of Scots pine (Pinus sylvestris has been made in Irik Valley, near Elbrus glacier, and a tree-ring width (TRW chronology has been used to reconstruct May – August (MJJA temperatures back to 1830. Three warm periods were identified in the MJJA temperatures reconstructed data (1830 - 1900, but we cannot appreciate if they had the same intensity as the recent warm period

Microbial responses to carbon and nitrogen supplementation in an Antarctic dry valley soil

DEFF Research Database (Denmark)

Dennis, P. G.; Sparrow, A. D.; Gregorich, E. G.

2013-01-01

The soils of the McMurdo Dry Valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain active biological communities that contribute to the biogeochemical processes. We have used ester-linked fatty acid (ELFA) analysis to investigate the effects of additions of carbon...... and nitrogen in glucose and ammonium chloride, respectively, on the soil microbial community in a field experiment lasting three years in the Garwood Valley. In the control treatment, the total ELFA concentration was small by comparison with temperate soils, but very large when expressed relative to the soil...... organic carbon concentration, indicating efficient conversion of soil organic carbon into microbial biomass and rapid turnover of soil organic carbon. The ELFA concentrations increased significantly in response to carbon additions, indicating that carbon supply was the main constraint to microbial...

Combination of RNAseq and SNP nanofluidic array reveals the center of genetic diversity of cacao pathogen Moniliophthora roreri in the upper Magdalena Valley of Colombia and its clonality

Directory of Open Access Journals (Sweden)

Shahin S Ali

2015-08-01

Full Text Available Moniliophthora roreri is the fungal pathogen that causes frosty pod rot (FPR disease of Theobroma cacao L., the source of chocolate. FPR occurs in most of the cacao producing countries in the Western Hemisphere, causing yield losses up to 80%. Genetic diversity within the FPR pathogen population may allow the population to adapt to changing environmental conditions and adapt to enhanced resistance in the host plant. The present study developed SNP markers from RNASeq results for 13 M. roreri isolates and validated the markers for their ability to reveal genetic diversity in an international M. roreri collection. The SNP resources reported herein represent the first study of RNASeq-derived SNP validation in M. roreri and demonstrates the utility of RNASeq as an approach for de novo SNP identification in M. roreri. A total of 88 polymorphic SNPs were used to evaluate the genetic diversity of 172 M. roreri cacao isolates resulting in 37 distinct genotypes (including 14 synonymous groups. Absence of heterozygosity for the 88 SNP markers indicates reproduction in M. roreri is clonal and likely due to a homothallic life style. The upper Magdalena Valley of Colombia showed the highest levels of genetic diversity with 20 distinct genotypes of which 13 were limited to this region, and indicates this region as the possible center of origin for M. roreri.

Combination of RNAseq and SNP nanofluidic array reveals the center of genetic diversity of cacao pathogen Moniliophthora roreri in the upper Magdalena Valley of Colombia and its clonality.

Science.gov (United States)

Ali, Shahin S; Shao, Jonathan; Strem, Mary D; Phillips-Mora, Wilberth; Zhang, Dapeng; Meinhardt, Lyndel W; Bailey, Bryan A

2015-01-01

Moniliophthora roreri is the fungal pathogen that causes frosty pod rot (FPR) disease of Theobroma cacao L., the source of chocolate. FPR occurs in most of the cacao producing countries in the Western Hemisphere, causing yield losses up to 80%. Genetic diversity within the FPR pathogen population may allow the population to adapt to changing environmental conditions and adapt to enhanced resistance in the host plant. The present study developed single nucleotide polymorphism (SNP) markers from RNASeq results for 13 M. roreri isolates and validated the markers for their ability to reveal genetic diversity in an international M. roreri collection. The SNP resources reported herein represent the first study of RNA sequencing (RNASeq)-derived SNP validation in M. roreri and demonstrates the utility of RNASeq as an approach for de novo SNP identification in M. roreri. A total of 88 polymorphic SNPs were used to evaluate the genetic diversity of 172 M. roreri cacao isolates resulting in 37 distinct genotypes (including 14 synonymous groups). Absence of heterozygosity for the 88 SNP markers indicates reproduction in M. roreri is clonal and likely due to a homothallic life style. The upper Magdalena Valley of Colombia showed the highest levels of genetic diversity with 20 distinct genotypes of which 13 were limited to this region, and indicates this region as the possible center of origin for M. roreri.

High gene flow and genetic diversity in three economically important Zanthoxylum Spp. of Upper Brahmaputra Valley Zone of NE India using molecular markers.

Science.gov (United States)

Medhi, K; Sarmah, D K; Deka, M; Bhau, B S

2014-12-01

The genetic diversity in Zanthoxylum species viz.  Zanthoxylum nitidum, Zanthoxylum oxyphyllum and Zanthoxylum rhesta collected from the Upper Brahmaputra Valley Zone of Assam (NE India) was amplified using 13 random amplified polymorphic DNA (RAPD) markers and 9 inter-simple sequence repeat (ISSR) markers. RAPD markers were able to detect 81.82% polymorphism whereas ISSR detected 98.02% polymorphism. The genetic similarities were analyzed from the dendrogram constructed by RAPD and ISSR fingerprinting methods which divided the 3 species of Zanthoxylum into 3 clear different clusters. The principle component analysis (PCA) was carried out to confirm the clustering pattern of RAPD and ISSR analysis. Analysis of molecular variance (AMOVA) revealed the presence of significant variability between different Zanthoxylum species and within the species by both RAPD and ISSR markers. Z. nitidum was found to be sharing a high degree of variation with the other two Zanthoxylum species under study. The Nei's gene diversity (h), Shannon's information index (I), observed number of alleles (na) and effective number of alleles (ne) were also found to be higher in ISSR markers (0.3526, 0.5230, 1.9802 and 1.6145) than in RAPD markers (0.3144, 0.4610, 1.8182 and 1.5571). The values for total genotype diversity for among population (HT), within population diversity (Hs) and gene flow (Nm) were more in ISSR (0.3491, 0.2644 and 1.5610) than RAPD (0.3128, 0.2264 and 1.3087) but the mean coefficient of gene differentiation (GST) was more in RAPD (0.2764) than ISSR (0.2426). A comparison of this two finger printing methods was done by calculating MR, EMI and MI. The correlation coefficient between data matrices of RAPD and ISSR based on Mantel test was found to be significant (r = 0.65612).

CO2 emissions from a temperate drowned river valley estuary adjacent to an emerging megacity (Sydney Harbour)

Science.gov (United States)

Tanner, E. L.; Mulhearn, P. J.; Eyre, B. D.

2017-06-01

The Sydney Harbour Estuary is a large drowned river valley adjacent to Sydney, a large urban metropolis on track to become a megacity; estimated to reach a population of 10 million by 2100. Monthly underway surveys of surface water pCO2 were undertaken along the main channel and tributaries, from January to December 2013. pCO2 showed substantial spatio-temporal variability in the narrow high residence time upper and mid sections of the estuary, with values reaching a maximum of 5650 μatm in the upper reaches and as low as 173 μatm in the mid estuary section, dominated by respiration and photosynthesis respectively. The large lower estuary displayed less variability in pCO2 with values ranging from 343 to 544 μatm controlled mainly by tidal pumping and temperature. Air-water CO2 emissions reached a maximum of 181 mmol C m-2 d-1 during spring in the eutrophic upper estuary. After a summer high rainfall event nutrient-stimulated biological pumping promoted a large uptake of CO2 transitioning the Sydney Harbour Estuary into a CO2 sink with a maximum uptake of rate of -10.6 mmol C m-2 d-1 in the mid-section of the estuary. Annually the Sydney Harbour Estuary was heterotrophic and a weak source of CO2 with an air-water emission rate of 1.2-5 mmol C m-2 d-1 (0.4-1.8 mol C m-2 y-1) resulting in a total carbon emission of around 930 tonnes per annum. CO2 emissions (weighted m3 s-1 of discharge per km2 of estuary surface area) from Sydney Harbour were an order of magnitude lower than other temperate large tectonic deltas, lagoons and engineered systems of China, India, Taiwan and Europe but were similar to other natural drowned river valley systems in the USA. Discharge per unit area appears to be a good predictor of CO2 emissions from estuaries of a similar climate and geomorphic class.

Ultra-high field upper extremity peripheral nerve and non-contrast enhanced vascular imaging.

Directory of Open Access Journals (Sweden)

Shailesh B Raval

Full Text Available The purpose of this study was to explore the efficacy of Ultra-high field [UHF] 7 Tesla [T] MRI as compared to 3T MRI in non-contrast enhanced [nCE] imaging of structural anatomy in the elbow, forearm, and hand [upper extremity].A wide range of sequences including T1 weighted [T1] volumetric interpolate breath-hold exam [VIBE], T2 weighted [T2] double-echo steady state [DESS], susceptibility weighted imaging [SWI], time-of-flight [TOF], diffusion tensor imaging [DTI], and diffusion spectrum imaging [DSI] were optimized and incorporated with a radiofrequency [RF] coil system composed of a transverse electromagnetic [TEM] transmit coil combined with an 8-channel receive-only array for 7T upper extremity [UE] imaging. In addition, Siemens optimized protocol/sequences were used on a 3T scanner and the resulting images from T1 VIBE and T2 DESS were compared to that obtained at 7T qualitatively and quantitatively [SWI was only qualitatively compared]. DSI studio was utilized to identify nerves based on analysis of diffusion weighted derived fractional anisotropy images. Images of forearm vasculature were extracted using a paint grow manual segmentation method based on MIPAV [Medical Image Processing, Analysis, and Visualization].High resolution and high quality signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]-images of the hand, forearm, and elbow were acquired with nearly homogeneous 7T excitation. Measured [performed on the T1 VIBE and T2 DESS sequences] SNR and CNR values were almost doubled at 7T vs. 3T. Cartilage, synovial fluid and tendon structures could be seen with higher clarity in the 7T T1 and T2 weighted images. SWI allowed high resolution and better quality imaging of large and medium sized arteries and veins, capillary networks and arteriovenous anastomoses at 7T when compared to 3T. 7T diffusion weighted sequence [not performed at 3T] demonstrates that the forearm nerves are clearly delineated by fiber tractography. The

Valley-Fill Sandstones in the Kootenai Formation on the Crow Indian Reservation, South-Central Montana

Energy Technology Data Exchange (ETDEWEB)

Lopez, David A

1998-07-03

Subsurface data continues to be collected, organized, and a digital database is being prepared for the project. An ACCESS database and PC-Arcview is being used to manage and interpret the data. Well data and base map data have been successfully imported into Arcview and customized to meet the needs of this project. Log tops and other data from about ¾ of the exploration wells in the area have been incorporated into the data base. All of the four 30" X 60" geologic quadrangles have been scanned to produce a digital surface geologic data base for the Crow Reservation and all are nearing completion. Formal technical review prior to publication has been completed for all the quadrangles; Billings, Bridger; Hardin, and Lodge Grass. Final GIS edits are being made before being forwarded to the Bureau's Publications Department. Field investigations were completed during the third quarter, 1997. With the help of a student field assistant from the Crow Tribe, the entire project area was inventoried for the presence of valley-fill deposits in the Kootenai Formation. Field inventory has resulted in the identification of nine exposures of thick valley-fill deposits. These appear to represent at least four major westward-trending valley systems. All the channel localities have been measured and described in detail and paleocurrent data has been collected from all but one locality. In addition, two stratigraphic sections were measured in areas where channels are absent. One channel has bee traced over a distance of about 60 miles and exhibits definite paleostructural control. An abstract describing this channel has been submitted and accepted for presentation at the Williston Basin Symposium in October, 1998.

Quantitative analysis of surface characteristics and morphology in Death Valley, California using AIRSAR data

Science.gov (United States)

Kierein-Young, K. S.; Kruse, F. A.; Lefkoff, A. B.

1992-01-01

The Jet Propulsion Laboratory Airborne Synthetic Aperture Radar (JPL-AIRSAR) is used to collect full polarimetric measurements at P-, L-, and C-bands. These data are analyzed using the radar analysis and visualization environment (RAVEN). The AIRSAR data are calibrated using in-scene corner reflectors to allow for quantitative analysis of the radar backscatter. RAVEN is used to extract surface characteristics. Inversion models are used to calculate quantitative surface roughness values and fractal dimensions. These values are used to generate synthetic surface plots that represent the small-scale surface structure of areas in Death Valley. These procedures are applied to a playa, smooth salt-pan, and alluvial fan surfaces in Death Valley. Field measurements of surface roughness are used to verify the accuracy.

Proximity-induced spin-valley polarization in silicene or germanene on F-doped WS2

KAUST Repository

Sattar, Shahid

2016-11-11

Silicene and germanene are key materials for the field of valleytronics. However, interaction with the substrate, which is necessary to support the electronically active medium, becomes a major obstacle. In the present work, we propose a substrate (F-doped WS2) that avoids detrimental effects and at the same time induces the required valley polarization, so that no further steps are needed for this purpose. The behavior is explained by proximity effects on silicene or germanene, as demonstrated by first-principles calculations. Broken inversion symmetry due to the presence of WS2 opens a substantial band gap in silicene or germanene. F doping of WS2 results in spin polarization, which, in conjunction with proximity-enhanced spin-orbit coupling, creates sizable spin-valley polarization.

Natural heat storage in a brine-filled solar pond in the Tully Valley of central New York

Science.gov (United States)

Hayhurst, Brett; Kappel, William M.

2014-01-01

The Tully Valley, located in southern Onondaga County, New York, has a long history of unusual natural hydrogeologic phenomena including mudboils (Kappel, 2009), landslides (Tamulonis and others, 2009; Pair and others, 2000), landsurface subsidence (Hackett and others, 2009; Kappel, 2009), and a brine-filled sinkhole or “Solar pond” (fig. 1), which is documented in this report. A solar pond is a pool of salty water (brine) which stores the sun’s energy in the form of heat. The saltwater naturally forms distinct layers with increasing density between transitional zones (haloclines) of rapidly changing specific conductance with depth. In a typical solar pond, the top layer has a low salt content and is often times referred to as the upper convective zone (Lu and others, 2002). The bottom layer is a concentrated brine that is either convective or temperature stratified dependent on the surrounding environment. Solar insolation is absorbed and stored in the lower, denser brine while the overlying halocline acts as an insulating layer and prevents heat from moving upwards from the lower zone (Lu and others, 2002). In the case of the Tully Valley solar pond, water within the pond can be over 90 degrees Fahrenheit (°F) in late summer and early fall. The purpose of this report is to summarize observations at the Tully Valley brine-filled sinkhole and provide supplemental climate data which might affect the pond salinity gradients insolation (solar energy).

Abiotic partitioning of clothianidin under simulated rice field conditions.

Science.gov (United States)

Mulligan, Rebecca A; Parikh, Sanjai J; Tjeerdema, Ronald S

2015-10-01

Clothianidin is registered for pre- and post-flood application in Californian rice fields for control of the rice seed midge, Cricotopus sylvestris, and the rice water weevil, Lissorhoptrus oryzophilus. The objective was to characterize air-water and soil-water partitioning of clothianidin under simulated Californian rice field conditions. Clothianidin was confirmed to be non-volatile (from water) via the gas purge method, as no loss from the aqueous phase was observed at 22 and 37 °C; an upper-limit KH value was calculated at 2.9 × 10(-11) Pa m(3) mol(-1) (20 °C). Soil-water partitioning was determined by the batch equilibrium method using four soils collected from rice fields in the Sacramento Valley, and sorption affinity (Kd ), sorbent capacity, desorption and organic-carbon-normalized distribution (Koc ) were determined. Values for pH, cation exchange capacity and organic matter content ranged from 4.5 to 6.6, from 5.9 to 37.9 and from 1.25 to 1.97% respectively. The log Koc values (22 and 37 °C) ranged from 2.6 to 2.7, while sorption capacity was low at 22 °C and decreased further at 37 °C. Hysteresis was observed in soils at both temperatures, suggesting that bound residues do not readily desorb. Soil-water and air-water partitioning will not significantly reduce offsite transport of clothianidin from flooded rice fields via drainage. © 2014 Society of Chemical Industry.

Groundwater quality in Coachella Valley, California

Science.gov (United States)

Dawson, Barbara J. Milby; Belitz, Kenneth

2012-01-01

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

Rock-avalanche dynamics revealed by large-scale field mapping and seismic signals at a highly mobile avalanche in the West Salt Creek valley, western Colorado

Science.gov (United States)

Coe, Jeffrey A.; Baum, Rex L.; Allstadt, Kate E.; Kochevar, Bernard; Schmitt, Robert G.; Morgan, Matthew L.; White, Jonathan L.; Stratton, Benjamin T.; Hayashi, Timothy A.; Kean, Jason W.

2016-01-01

On 25 May 2014, a rain-on-snow–induced rock avalanche occurred in the West Salt Creek valley on the northern flank of Grand Mesa in western Colorado (United States). The avalanche mobilized from a preexisting rock slide in the Green River Formation and traveled 4.6 km down the confined valley, killing three people. The avalanche was rare for the contiguous United States because of its large size (54.5 Mm3) and high mobility (height/length = 0.14). To understand the avalanche failure sequence, mechanisms, and mobility, we conducted a forensic analysis using large-scale (1:1000) structural mapping and seismic data. We used high-resolution, unmanned aircraft system imagery as a base for field mapping, and analyzed seismic data from 22 broadband stations (distances earth and tracked these forces using curves in the avalanche path. Our results revealed that the rock avalanche was a cascade of landslide events, rather than a single massive failure. The sequence began with an early morning landslide/debris flow that started ∼10 h before the main avalanche. The main avalanche lasted ∼3.5 min and traveled at average velocities ranging from 15 to 36 m/s. For at least two hours after the avalanche ceased movement, a central, hummock-rich core continued to move slowly. Since 25 May 2014, numerous shallow landslides, rock slides, and rock falls have created new structures and modified avalanche topography. Mobility of the main avalanche and central core was likely enhanced by valley floor material that liquefied from undrained loading by the overriding avalanche. Although the base was likely at least partially liquefied, our mapping indicates that the overriding avalanche internally deformed predominantly by sliding along discrete shear surfaces in material that was nearly dry and had substantial frictional strength. These results indicate that the West Salt Creek avalanche, and probably other long-traveled avalanches, could be modeled as two layers: a thin, liquefied

The valley method and its application to the instanton-induced phenomena in non-abelian gauge theories

International Nuclear Information System (INIS)

Khoze, V.V.

1991-06-01

The semiclassical evaluation of the functional integral on non-Abelian gauge theories is generalized by means of the so-called valley method. The physically very important example of the valley, the instanton-anti-instanton field configuration, is discussed in details and its contributions to the physical quantities for zero-temperature and for thermal field theories are investigated. The high-energy behaviour of the total cross-section σ Δ F for electroweak fermion number violating two particles collisions is studied using the optical theorem approach. The calculation is done at energies below the sphaleron mass (E<10TeV) where it leads to the most complete result for σ Δ F known to date. Some estimations and a qualitative physical picture are discussed for energies above the sphaleron mass for the confinement and Higgs phases of the gauge theory. The effects of instanton-anti-instanton interactions are also studied in thermal QCD. (au)

Improved Mars Upper Atmosphere Climatology

Science.gov (United States)

Bougher, S. W.

2004-01-01

The detailed characterization of the Mars upper atmosphere is important for future Mars aerobraking activities. Solar cycle, seasonal, and dust trends (climate) as well as planetary wave activity (weather) are crucial to quantify in order to improve our ability to reasonably depict the state of the Mars upper atmosphere over time. To date, our best information is found in the Mars Global Surveyor (MGS) Accelerometer (ACC) database collected during Phase 1 (Ls = 184 - 300; F10.7 = 70 - 90) and Phase 2 (Ls = 30 - 90; F10.7 = 90 - 150) of aerobraking. This database (100 - 170 km) consists of thermospheric densities, temperatures, and scale heights, providing our best constraints for exercising the coupled Mars General Circulation Model (MGCM) and the Mars Thermospheric General Circulation Model (MTGCM). The Planetary Data System (PDS) contains level 0 and 2 MGS Accelerometer data, corresponding to atmospheric densities along the orbit track. Level 3 products (densities, temperatures, and scale heights at constant altitudes) are also available in the PDS. These datasets provide the primary model constraints for the new MGCM-MTGCM simulations summarized in this report. Our strategy for improving the characterization of the Mars upper atmospheres using these models has been three-fold : (a) to conduct data-model comparisons using the latest MGS data covering limited climatic and weather conditions at Mars, (b) to upgrade the 15-micron cooling and near-IR heating rates in the MGCM and MTGCM codes for ad- dressing climatic variations (solar cycle and seasonal) important in linking the lower and upper atmospheres (including migrating tides), and (c) to exercise the detailed coupled MGCM and MTGCM codes to capture and diagnose the planetary wave (migrating plus non-migrating tidal) features throughout the Mars year. Products from this new suite of MGCM-MTGCM coupled simulations are being used to improve our predictions of the structure of the Mars upper atmosphere for the

Upper critical fields in Ba2Ti2Fe2As4O single crystals: Evidence for dominant Pauli paramagnetic effect

Science.gov (United States)

Abdel-Hafiez, M.; Brisbois, J.; Zhu, Z.; Adamski, A.; Hassen, A.; Vasiliev, A. N.; Silhanek, A. V.; Krellner, C.

2018-03-01

We report on magneto-optical imaging and the temperature dependency of the upper critical fields Hc2 c(T ) parallel to the c axis and Hc2 a b(T ) parallel to the a b plane in Ba2Ti2Fe2As4O single crystals. These data were inferred from the measurements of the temperature-dependent resistance in static magnetic fields up to 14 T and magnetoresistance in pulsed fields up to 60 T. Hc 2 values are found to be 52 and 50 T for H ∥a b and H ∥c , respectively. These values are 1.2-1.35 times larger than the weak-coupling Pauli paramagnetic limit (Hp˜1.84 Tc ), indicating that enhanced paramagnetic limiting is essential and this superconductor is unconventional. Our observations of strong bending in the Hc2 a b(T ) curves and a nearly isotropic maximum upper critical field Hc2 a b(0 ) ≈Hc2 c(0 ) support the presence of a strong Pauli paramagnetic effect. We show that the Werthamer-Helfand-Hohenberg (WHH) formula that includes the spin-orbit scattering can effectively describe the Hc2 a b(T ) curve, whereas Hc 2 deviates from the conventional WHH theoretical model without considering the spin paramagnetic effect for the H ∥c and H ∥a b directions. For H ∥c , a two-band model is required to fully reproduce the behavior of Hc 2, while for H ∥a b the spin paramagnetic effect is responsible for the behavior of Hc 2. The anisotropy of Hc 2 is close to 3 near Tc and decreases rapidly at lower temperatures.

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

Science.gov (United States)

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

Breathing Valley Fever

Centers for Disease Control (CDC) Podcasts

2014-02-04

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

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

Science.gov (United States)

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

2014-01-01

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

Landscape Change and Microbial Response in the McMurdo Dry Valleys, Antarctica: Preliminary Results

Science.gov (United States)

Fountain, A. G.; Levy, J.; Gooseff, M. N.; Van Horn, D. J.; Obryk, M.; Pettersson, R.; Telling, J. W.; Glennie, C. L.

2017-12-01

Permafrost in the McMurdo Dry Valleys (MDV), Antarctica is ubiquitous with active layer depths ranging from a few cm at the highest elevations to 1 m near sea level. Although many landscapes in this region have been considered stable over millennia, ad-hoc field observations have documented extreme geomorphic changes in the valley bottoms over the past decade. To assess these changes across the region, we compared a lidar dataset surveyed in the austral summers of 2001-2002 against one surveyed in 2014-2015. Results showed that the vertical resolution of the surveys was resolution of the elevation differences and we ignored differences 1m) landscape changes, including stream channel incision into buried ice deposits (implying the advection of heat by stream water locally degrades thermokarst) and slope failures in thermokarst landforms from block failure and insolation-driven retreat. Smaller changes (bank erosion intercepted buried ice, or in thermokarst ponds. The magnitude and rate of change is much larger than observed previously in this otherwise stable and slowly changing environment. Biological surveys and experimental manipulations show that wetted soils host microbial communities different from those hosted by adjacent dry soils, and are hotspots of biodiversity highly susceptible to changing physical conditions. In all cases field-checked, the association of sediment and rock debris blanketing buried ice was noted, indicating these are the most vulnerable landscapes to climate warming. Ground penetrating radar mapping of buried ice showed, however, that not all buried ice is associated with landscape change due to the depth of burial, slope, and proximity to stream water. Similarly, modeling of soil temperatures suggests a spatial heterogeneity in warming rates across the valley bottom, as a consequence of microclimatic influences, topographic shading and moisture content. Collectively, these conditions imply that landscapes in the MDV will become

Biostratigraphy and carbon isotope stratigraphy of uppermost Cretaceous-lower Cenozoic Muzzle Group in middle Clarence valley, New Zealand

International Nuclear Information System (INIS)

Hollis, C.J.; Field, B.D.; Jones, C.M.; Strong, C.P.; Wilson, G.J.; Dickens, G.R.

2005-01-01

Muzzle Group strata exposed along southeast-flowing tributaries of the Clarence River valley, Marlborough, record hemipelagic-pelagic sedimentation across a high latitude (c. 55 degrees S), terrigenous sediment-starved, continental margin from latest Cretaceous to middle Eocene times. Studies of dinoflagellates, foraminifera, calcareous nannofossils, and radiolarians have been integrated with bulk carbonate δ 13 C profiles to establish the chronostratigraphy for two stratigraphic sections along Bluff and Muzzle Streams, middle Clarence valley. The two sections comprise similar successions. Uppermost Cretaceous (upper Haumurian) micritic limestone of Mead Hill Formation is overlain unconformably by Teredo Limestone, a c. 0.25 m thick bed of highly glauconitic, calcareous sandstone. This unit, the basal member of Amuri Limestone, is overlain conformably by c. 15 m thick Lower Limestone, micritic limestone that is glauconitic at base and progressively more marl-rich in its upper part. Lower Limestone grades up into Lower Marl, a poorly exposed, 40-70 m thick unit of alternating marl and micritic limestone beds. Biostratigraphy indicates that the base of Amuri Limestone is younger at Bluff Stream (earliest Eocene, early Waipawan) than at Muzzle Stream (late Paleocene, late Teurian). In the condensed (12 m) upper Paleocene-lower Eocene Amuri Limestone sequence at Muzzle Stream, a trend in δ 13 C from high (≥2.4 permille) to low (≤1 permille) values is consistent with global records across three major climate or carbon cycle perturbations: the late Paleocene carbon isotope maximum (PCIM, 59-56 Ma), the initial Eocene thermal maximum (IETM, 55.5 Ma), and the early Eocene climatic optimum (EECO, 53-50 Ma). Probably only the upper PCIM is preserved in the 4 m thick siliceous limestone interval overlying Teredo Limestone. The IETM is well-defined by a 1 permille negative δ 13 C excursion at the base of a 0.8 m thick marl-rich unit (Dee Marl), 5 m above the base of

Sand dune movement in the Victoria Valley, Antarctica

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Bourke, Mary C.; Ewing, Ryan C.; Finnegan, David; McGowan, Hamish A.

2009-08-01

We use vertical aerial photographs and LiDAR topographic survey data to estimate dune migration rates in the Victoria Valley dunefield, Antarctica, between 1961 and 2001. Results confirm that the dunes migrated an average of 1.5 m/year. These values are consistent with other estimates of dune migration from cold climate deserts and are significantly lower than estimates from warm deserts. Dune migration rates are retarded by the presence of entrained ice, soil moisture and a reversing wind regime. Dune absorption, merging and limb extension are apparent from the time-series images and account for significant changes in dune form and the field-scale dune pattern. Dune-field pattern analysis shows an overall increase in dune-field organization with an increase in mean dune spacing and a reduction in total crest length and defect density. These data suggest that dunes in other cold desert environments on Earth, Mars or Titan, that may also have inter-bedded frozen laminae, still have the potential to migrate and organize, albeit at lower rates than dunes in warm deserts.

Reworked Middle Jurassic sandstones as a marker for Upper Cretaceous basin inversion in Central Europe—a case study for the U-Pb detrital zircon record of the Upper Cretaceous Schmilka section and their implication for the sedimentary cover of the Lausitz Block (Saxony, Germany)

Science.gov (United States)

Hofmann, Mandy; Voigt, Thomas; Bittner, Lucas; Gärtner, Andreas; Zieger, Johannes; Linnemann, Ulf

2018-04-01

The Saxonian-Bohemian Cretaceous Basin (Elbsandsteingebirge, E Germany and Czech Republic, Elbtal Group) comprises Upper Cretaceous sedimentary rocks from Upper Cenomanian to Santonian age. These sandstones were deposited in a narrow strait of the sea linking the northern Boreal shelf to the southern Tethyan areas. They were situated between the West Sudetic Island in the north and the Mid-European Island in the south. As known by former studies (e.g. Tröger, Geologie 6/7:717-730, 1964; Tröger, Geologie von Sachsen, Schweizerbart, 311-358, 2008; Voigt and Tröger, Proceedings of the 4th International Cretaceous Symposium, 275-290, 1996; Voigt, Dissertation, TU Bergakademie Freiberg, 1-130, 1995; Voigt, Zeitschrift der geologischen Wissenschaften 37(1-2): 15-39, 2009; Wilmsen et al., Freiberger Forschungshefte C540: 27-45, 2011) the main sedimentary input came from the north (Lausitz Block, southern West-Sudetic Island). A section of Turonian to Coniacian sandstones was sampled in the Elbsandsteingebirge near Schmilka (Elbtal Group, Saxony, Germany). The samples were analysed for their U-Pb age record of detrital zircon using LA-ICP-MS techniques. The results show main age clusters typical for the Bohemian Massif (local material) and are interpreted to reflect the erosion of uniform quartz-dominated sediments and basement rocks. Surprisingly, these rocks lack an expected Upper Proterozoic to Lower Palaeozoic age peak, which would be typical for the basement of the adjacent Lausitz Block (c. 540-c. 560 Ma). Therefore, the Lausitz Block basement must have been covered by younger sediments that acted as source rocks during deposition of the Elbtal Group. The sandstones of the Elbe valley (Elbtal Group, Schmilka section) represent the re-deposited sedimentary cover of the Lausitz Block in inverse order. This cover comprised Permian, Triassic, Jurassic and Lower Cretaceous deposits, which are eroded already today and cannot be investigated. Within the samples of the

Stratigraphy, facies analysis and depositional environments of the Upper Unit of Abu Roash "E" member in the Abu Gharadig field, Western Desert, Egypt

Science.gov (United States)

Hewaidy, Abdel Galil; Elshahat, O. R.; Kamal, Samy

2018-03-01

Abu Roach "E" member is of an important hydrocarbon reservoir-producing horizon in the Abu Gharadig Field (north Western Desert, Egypt). This study is used to build facies analysis and depositional environments model for the Upper Unit of the Abu Roash "E" member in Abu Gharadig Field. This target has been achieved throughout the sedimentological, wire line logs, lithostratigraphic and biostratigraphic analyses of more than 528 feet cores. The high-resolution biostratigraphic analysis provides a calibration for the paleo-bathymetry and depositional environmental interpretations. Biozonation and lithostratigraphic markers are used to constrain stratigraphic correlation. Integration between the core description and petorographic microfacies analysis by microscope examination provide an excellent indication for the rock types and depositional environments. Five depositional facies types are detected including carbonate inner ramp, tidal flats, tidal channels, supra-tidal and tide dominated delta facies. This model helps in the understanding of the Upper Unit of Abu Roash "E" member reservoir distribution as well as lateral and vertical facies changes that contribute to the development strategy for the remaining hydrocarbon reserves for this important oil reservoir.

Tunable zero-line modes via magnetic field in bilayer graphene

Science.gov (United States)

Wang, Ke; Qiao, Zhenhua

Zero-line modes appear in bilayer graphene at the internal boundary between two opposite vertical electrostatic confinements. These one-dimensional modes are metallic along the boundary and exhibit quantized conductance in the absence of inter-valley scattering. However, experimental results show that the conductance is around 0.5 e2/h rather than quantized. This observation can be explained from our numerical results, which suggest that the scattering between zero-line mode and bound states and the presence of atomic scale disorders that provide inter-valley scattering can effectively reduce the conductance to about 0.5 e2/h. We further find that out-of-plane magnetic field can strongly suppress these scattering mechanisms and gives rise to nearly quantized conductance. On one hand, the presence of magnetic field makes bound states become Landau levels, which reduces the scattering between zero-line mode and bound states. On the other hand, the wave function distributions of oppositely propagating zero-line modes at different valleys are spatially separated, which can strongly suppress the inter-valley scattering. Specifically speaking, the conductance can be increased to 3.2 e2/h at 8 T even when the atomic Anderson type disorders are considered.

Preliminary stratigraphy and facies analysis of the Upper Cretaceous Kaguyak Formation, including a brief summary of newly discovered oil stain, upper Alaska Peninsula

Science.gov (United States)

Wartes, Marwan A.; Decker, Paul L.; Stanley, Richard G.; Herriott, Trystan M.; Helmold, Kenneth P.; Gillis, Robert J.

2013-01-01

The Alaska Division of Geological and Geophysical Surveys has an ongoing program aimed at evaluating the Mesozoic forearc stratigraphy, structure, and petroleum systems of lower Cook Inlet. Most of our field studies have focused on the Jurassic component of the petroleum system (this report). However, in late July and early August of 2012, we initiated a study of the stratigraphy and reservoir potential of the Upper Cretaceous Kaguyak Formation. The Kaguyak Formation is locally well exposed on the upper Alaska Peninsula (fig. 25) and was named by Keller and Reiser (1959) for a sequence of interbedded siltstone and sandstone of upper Campanian to Maastrichtian age that they estimated to be 1,450 m thick.Subsequent work by Detterman and Miller (1985) examined 900 m of section and interpreted the unit as the record of a prograding submarine fan.This interpretation of deep-water deposition contrasts with other Upper Cretaceous rocks exposed along the Alaska Peninsula and lower Cook Inlet that are generally described as nonmarine to shallow marine (Detterman and others, 1996; LePain and others, 2012).Based on foraminifera and palynomorphs from the COST No. 1 well, Magoon (1986) concluded that the Upper Cretaceous rocks were deposited in a variety of water depths and environments ranging from upper bathyal to nonmarine. During our recent fieldwork west and south of Fourpeaked Mountain, we similarly encountered markedly varying lithofacies in the Kaguyak Formation (fig. 25), and we also found oil-stained rocks that are consistent with the existence of an active petroleum system in Upper Cretaceous rocks on the upper Alaska Peninsula and in lower Cook Inlet. These field observations are summarized below.

Potential hydrologic characterization wells in Amargosa Valley

International Nuclear Information System (INIS)

Lyles, B.; Mihevc, T.

1994-09-01

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

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

Science.gov (United States)

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

2016-12-05

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

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

Science.gov (United States)

1981-01-24

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

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

Science.gov (United States)

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

2014-12-01

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

Intermontane eolian sand sheet development, Upper Tulum Valley, central-western Argentina

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Patrick Francisco Fuhr Dal' Bó

Full Text Available ABSTRACTThe intermontane Upper Tulum eolian sand sheet covers an area of ca. 125 km² at north of the San Juan Province, central-western Argentina. The sand sheet is currently an aggrading system where vegetation cover, surface cementation and periodic flooding withhold the development of dunes with slipfaces. The sand sheet surface is divided into three parts according to the distribution of sedimentary features, which reflects the variation in sediment budget, water table level and periodic flooding. The central sand sheet part is the main area of eolian deposition and is largely stabilized by vegetation. The sedimentary succession is 4 m thick and records the vertical interbedding of eolian and subaqueous deposits, which have been deposited for at least 3.6 ky with sedimentation rates of 86.1 cm/ky. The construction of the sand sheet is associated with deflation of the sand-graded debris sourced by San Juan alluvial fan, which is available mainly in drier fall-winter months where water table is lower and wind speeds are periodically above the threshold velocity for sand transport. The accumulation of sedimentary bodies occurs in a stabilized eolian system where vegetation cover, thin mud veneers and surface cementation are the main agents in promoting accumulation. The preservation of the sand sheet accumulations is enabled by the progressive creation of the accommodation space in a tectonically active basin and the continuous burial of geological bodies favored by high rates of sedimentation.

Gravity and magnetic data of Midway Valley, southwest Nevada

International Nuclear Information System (INIS)

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

1993-01-01

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

27 CFR 9.208 - Snake River Valley.

Science.gov (United States)

2010-04-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-05-28

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

Effects of TiC doping on the upper critical field of MgB2 superconductors