WorldWideScience

Sample records for subtidal zone influence

  1. Photoacclimatory Responses of Zostera marina in the Intertidal and Subtidal Zones.

    Directory of Open Access Journals (Sweden)

    Sang Rul Park

    Full Text Available Photoacclimatory responses of the seagrass Zostera marina in the intertidal and subtidal zones were investigated by measuring chlorophyll a fluorescence parameters, photosynthetic pigments, leaf δ13C values, and shoot morphology in two bay systems. Intertidal plants had higher carotenoid concentrations than subtidal plants to avoid photodamage under excess light conditions during the day. The maximum relative electron transport rate (rETRmax and minimum saturation irradiance (Ek of the intertidal plants were higher than those of the subtidal plants, whereas photosynthetic efficiency (α and maximum quantum yield (Fv/Fm were higher in subtidal plants. The intertidal plants also had significantly greater Stern-Volmer non-photochemical quenching (NPQ than that of the subtidal plants. These results suggest that the subtidal plants photoacclimated to use limited light more efficiently, and the intertidal plants exhibited photosynthetic responses to minimize photodamage at excess irradiance. The δ13C values of leaf tissues were more negative in the intertidal plants than those in the subtidal plants, suggesting that the intertidal plants used atmospheric or dissolved CO2 for photosynthesis during emersion. Effective quantum yield (ΔF/Fm´ in the intertidal plants decreased more slowly after emersion than that in the subtidal plants, indicating higher desiccation tolerance of the intertidal plants. The intertidal plants also recovered more rapidly from desiccation damage than the subtidal plants, suggesting photosynthetic adaptation to desiccation stress. The photosynthetic plasticity of Z. marina in response to variable environmental conditions most likely allows this species to occur in the intertidal and subtidal zones.

  2. Reconnaissance of intertidal and subtidal zones of Back Island, Behm Canal, Southeast Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Strand, J.A.; Young, J.S.

    1986-09-01

    A diver reconnaissance of the intertidal and subtidal zones of Back Island, Southeast Alaska, was performed May 20-22, 1986. The specific objectives were to catalog potentially vulnerable shellfish, other invertebrates, and plant resources, and to identify potential herring spawning sites. This effort was designed to supplement the existing ecological data base for Back Island that would be used during the National Environmental Policy Act (NEPA) documentation process. A NEPA document will be prepared that describes the site environment and assesses impacts from the proposed construction and operation of the Southeast Alaska Acoustic Measurement Facility (SEAFAC). Nine diver transects were established around Back Island. Particular attention was devoted to proposed locations for the pier and float facilities and range-operations and shore-power cable run-ups.

  3. Formation and entrainment of fluid mud layers in troughs of subtidal dunes in an estuarine turbidity zone

    DEFF Research Database (Denmark)

    Becker, Marius; Schrottke, Kerstin; Bartholomä, Alexander

    2013-01-01

    The formation and entrainment of fluid mud layers in troughs of subtidal dunes were investigated in the Weser Estuary, North Sea, Germany, based on hydroacoustic measurements. Near-bed suspension layers were found to consist of a suspension of large mud flocs of variable concentration, ranging from...... 25 g/L below the lutocline to 70 g/L at the river bed, whereas the gelling concentration was below 70 g/L. Sites of fluid mud formation coincided with the location of the estuarine turbidity zone during slack water. On average, near-bed density gradients were initially observed in dune troughs 1.2 h...... before slack water, and all fluid mud layers were entrained 2.3 h after slack water. No shear instabilities occurred until 1.8 h after slack water. While the flow was oriented in the dune direction, rapid entrainment was related to the development of the turbulent flow field behind dunes and is explained...

  4. Intertidal and subtidal ecology

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.

    stream_size 13 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Mgmt_1993_48.pdf.txt stream_source_info Trg_Course_Coast_Zone_Mgmt_1993_48.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  5. Subtidal flow division at a shallow tidal junction

    NARCIS (Netherlands)

    Buschman, F.A.; Hoitink, A.J.F.; Vegt, van der M.; Hoekstra, P.

    2010-01-01

    Tides influence distribution of river discharge at tidally affected channel junctions. At the apex of a channel network in an Indonesian delta, observations of flow division suggest that tidally averaged flow division depends on the tidal range. To understand the mechanisms governing the subtidal

  6. Giant subtidal stromatolites forming in normal salinity waters

    Science.gov (United States)

    Dill, R.F.; Shinn, E.A.; Jones, A.T.; Kelly, K.; Steinen, R.P.

    1986-01-01

    We report here the discovery of giant lithified subtidal columnar stromatolites (>2 m high) growing in 7-8 m of clear oceanic water in current-swept channels between the Exuma Islands on the eastern Bahama Bank. They grow by trapping ooid and pelletal carbonate sand and synsedimentary precipitation of carbonate cement within a field of giant megaripples. The discovery is important to geologists and biologists because similar organo-sedimentary structures built by a combination of cementation and the trapping of sediment by microbes were the dominant fossil types during the Precambrian. Stromatolites are thought to have been responsible for the production of free oxygen and thus the evolution of animal life1,2. Until the discovery of small lithified subtidal columnar stromatolites in the Bahamas3, the only subtidal marine examples known to be living while undergoing lithification were in the hypersaline waters of Hamelin Pool at Shark Bay, Western Australia4-7. Shark Bay stromatolites range from intertidal to the shallow subtidal with the larger columns reaching 1 m in height. The Shark Bay stromatolites have strongly influenced geological interpretation; by analogy, many ancient stromatolites have been considered to have grown in intertidal and/or hypersaline conditions8, although hypersalinity was not a necessity for growth during the Precambrian because grazing metazoan life had not then evolved. ?? 1986 Nature Publishing Group.

  7. Hydrodynamic conditioning of diversity and functional traits in subtidal estuarine macrozoobenthic communities

    Science.gov (United States)

    van der Wal, Daphne; Lambert, Gwladys I.; Ysebaert, Tom; Plancke, Yves M. G.; Herman, Peter M. J.

    2017-10-01

    Variations in abundance and diversity of estuarine benthic macrofauna are typically described along the salinity gradient. The influence of gradients in water depth, hydrodynamic energy and sediment properties are less well known. We studied how these variables influence the distribution of subtidal macrofauna in the polyhaline zone of a temperate estuary (Westerschelde, SW Netherlands). Macrofauna density, biomass and species richness, combined in a so-called ecological richness, decreased with current velocities and median grain-size and increased with organic carbon of the sediment, in total explaining 39% of the variation. The macrofauna community composition was less well explained by the three environmental variables (approx. 12-15% in total, with current velocity explaining approx. 8%). Salinity, water depth and distance to the intertidal zone had a very limited effect on both ecological richness and the macrofauna community. The proportion of (surface) deposit feeders (including opportunistic species), decreased relative to that of omnivores and carnivores with increasing current velocity and sediment grain-size. In parallel, the proportion of burrowing sessile benthic species decreased relative to that of mobile benthic species that are able to swim. Correspondingly, spatial variations in hydrodynamics yielded distinct hotspots and coldspots in ecological richness. The findings highlight the importance of local hydrodynamic conditions for estuarine restoration and conservation. The study provides a tool based on a hydrodynamic model to assess and predict ecological richness in estuaries.

  8. Grown-out of seeds of the taquilla clam Mulinia edulis (King & Broderip, 1832 in the subtidal zone in northern Chile and in the intertidal zone in southern Chile Engorda de semillas de la almeja taquilla Mulinia edulis (King & Broderip, 1832 en la zona submareal en el norte y en la zona intermareal en el sur de Chile

    Directory of Open Access Journals (Sweden)

    Alejandro Abarca

    2012-09-01

    Full Text Available Seeds of the clam Mulinia edulis produced in a hatchery were grown in bottom cages in the subtidal zone of Tongoy Bay (northern Chile and in the intertidal zone of Chullec (Chiloé Island, southern Chile, to compare the growth and survival of small and large seeds of the same production in different environments and latitudes. Seeds were shipped twice to Chullec, once in summer and once in winter. Previous experiments with seed transportation (14.2 ± 2.4 mm showed that they are able to survive more than 24 h out of water. The growth rate of both large and small seeds was greater in Tongoy than in Chullec, reaching maxima of 1.24 mm month-1 in the small seeds of Tongoy and 1.06 mm month-1 in the same group in Chullec. The growth rates obtained for M. edulis were similar to those described for other cultured clams. Seeds grown in Chullec presented a significantly greater weight by size than the seeds grown in Tongoy. Survival after 12 months was 38% and 88% in Tongoy and 19.4% and 37.3% in Chullec for small and large seeds, respectively. Seeds produced in hatcheries are able to withstand long travel (1,360 km and grow in the intertidal zone of southern Chile, where the operation of the culture is simple and cheap. The growth curve presents an inflection point around 20 mm length, probably related to the age at sexual maturity. Growing out seeds in the intertidal zone in southern Chile is seen as a new activity for artisanal fishermen.Semillas de la almeja Mulinia edulis producidas en el Hatchery de Pesquera San José (Tongoy fueron engordadas en sistemas de fondo en la zona submareal de bahía Tongoy e intermareal en Chullec (Chiloé, para comparar el crecimiento y la supervivencia de semillas pequenas y grandes de una misma producción en diferentes ambientes y latitudes. Se realizaron dos envíos de semillas a Chullec, uno en verano y otro en invierno. Experimentos de simulación del transporte de semillas (14,2 ± 2,4 mm muestran que

  9. Habitat-associations of turban snails on intertidal and subtidal rocky reefs.

    Science.gov (United States)

    Smoothey, Amy F

    2013-01-01

    Patchiness of habitat has important influences on distributions and abundances of organisms. Given the increasing threat of loss and alteration of habitats due to pressures associated with humans, there is a need for ecologists to understand species' requirements for habitat and to predict changes to taxa under various future environmental conditions. This study tested hypotheses about the generality of patterns described for one species of marine intertidal turban snail for a different, yet closely-related species in subtidal habitats along the coast of New South Wales, Australia. These two closely-related species live in similar habitats, yet under quite different conditions, which provided an opportunity to investigate how similar types of habitats influence patterns of distribution, abundance and size-structure in intertidal versus subtidal environments. For each species, there were similar associations between biogenically structured habitat and densities. The intertidal species, Turbo undulates, were more abundant, with greater proportions of small individuals in habitats formed by the canopy-forming alga, Hormosira banksii, the solitary ascidian, Pyura stolonifera or the turfing red alga, Corallina officinalis compared to simple habitat (bare rock). Similarly, more Turbo torquatus were found in biogenically structured subtidal habitat, i.e. canopy-forming algae, Ecklonia radiata, mixed algal communities ('fringe'), or turfing red algae (Corallina officinalis and Amphiroa aniceps) than where habitat is simple (barrens). Small T. torquatus were more abundant in areas of turf and 'fringe', while large snails were more abundant in areas of kelp and barrens. These patterns were found at each location sampled (i.e. eight intertidal and two subtidal rocky reefs) and at all times of sampling, across each environment. This study highlighted the consistent influence of biogenically structured habitats on the distribution, abundance and size-structure of intertidal and

  10. Tidal impacts on the subtidal flow division at the main bifurcation in the Yangtze River Delta

    Science.gov (United States)

    Zhang, Wei; Feng, Haochuan; Hoitink, A. J. F.; Zhu, Yuliang; Gong, Fei; Zheng, Jinhai

    2017-09-01

    Flow division at bifurcations in the Yangtze Estuary has received ample attention, since it may control the pathways of terrestrial sediments over downstream river branches including the 12.5 m Deepwater Navigation channel. While some efforts have been made to interpret flow division at the bifurcations of the Yangtze Estuary, little attention has been paid to the role of tides. Flow division at estuarine bifurcations is made complicated by tides that propagate from the outlet of the tidal channels into the delta. To quantify the tidal influence on the distribution of river discharge, and more generally, to understand the mechanisms governing the subtidal flow division at the tidally affected bifurcation in the Yangtze River Delta, a two-dimensional hydrodynamic model is employed. In this model, the landward boundary is chosen beyond the tidal limit, where the tidal motion has faded out entirely. The seaward boundary is chosen such that the river discharge does not influence the water level. Subtidal discharges are decomposed using the method of factor separation, to distinguish between the effects of tides, river discharge and river-tide interactions on the subtidal flow division. Results indicate that tides modify the river discharge distribution over distributary channels in the Yangtze River Delta, particularly in the dry season. A significant difference in the subtidal flow division during spring tide and neap tide shows that the tidally averaged flow division over the distributaries in the delta greatly depends on tidal amplitude. By varying the river discharge at the landward boundary and amplitudes and phases of the principal tidal constituents at the seaward boundary of the established model, the sensitivities of the subtidal flow division to the river discharge and tidal amplitude variation were investigated in detail. Generally, the tidal impacts on the subtidal flow division are around 12% to 22%, with river discharge varying from 30,000 m3s-1 to 20

  11. Influence of soil and climate on root zone storage capacity

    Science.gov (United States)

    Euser, Tanja; McMillan, Hilary; Hrachowitz, Markus; Winsemius, Hessel; Savenije, Hubert

    2015-04-01

    The root zone water storage capacity (Sr) of a catchment is an important variable for the hydrological behaviour of a catchment; it strongly influences the storage, transpiration and runoff generation in an area. However, the root zone storage capacity is largely heterogeneous and not measurable. There are different theories about the variables affecting the root zone storage capacity; among the most debated are soil, vegetation and climate. The effect of vegetation and soil is often accounted for by detailed soil and land use maps. To investigate the effect of climate on the root zone storage capacity, an analogue can be made between the root zone storage capacity of a catchment and the human habit to design and construct reservoirs: both storage capacities help to overcome a dry period of a certain length. Humans often use the mass curve technique to determine the required storage needed to design the reservoir capacity. This mass curve technique can also be used to derive the root zone storage capacity created by vegetation in a certain ecosystem and climate (Gao et al., 2014). Only precipitation and discharge or evaporation data are required for this method. This study tests whether Sr values derived by both the mass curve technique and from soil maps are comparable for a range of catchments in New Zealand. Catchments are selected over a gradient of climates and land use. Special focus lies on how Sr values derived for a larger catchment are representative for smaller nested catchments. The spatial differences are examined between values derived from soil data and from climate and flow data. Gao, H., Hrachowitz, M., Schymanski, S.J., Fenicia, F., Sriwongsitanon, N., Savenije, H.H.G, (2014): Climate controls how ecosystems size the root zone storage capacity at catchment scale. DOI: 10.1002/2014GL061668

  12. Tidal and subtidal hydrodynamics and energetics in a constricted estuary

    Science.gov (United States)

    Zarzuelo, Carmen; López-Ruiz, Alejandro; Díez-Minguito, Manuel; Ortega-Sánchez, Miguel

    2017-02-01

    The dynamics of coastal plain estuaries are mainly associated with variable tidal forcing and local winds in combination with bathymetric complexity and coastline irregularity. Specific features, such as constricted areas, can potentially affect and energize the hydrodynamics of these types of systems. Particularly, tidal range and tidal currents can be significantly amplified where the incoming tidal wave becomes constricted. In this work, the impact of a narrow constriction on a mesotidal estuary was analysed at tidal and subtidal time scales. Tidal hydrodynamics, energy fluxes and energy dissipation were determined for the entire Cádiz Bay (southwestern Spain) using the Delft3D numerical model. Field observations were used to analyse tidal propagation and energy dissipation along the bay constriction and to calibrate and test the numerical model. The results indicate that the presence of the constriction transformed and distorted the tide and increased the tidal range and flow velocities along the channel, with implications on energy dissipation. The tidal currents were oriented along-channel at the central part of the constriction, although abrupt bathymetric changes at the channel inner boundary provoked a sudden rotation of the flow. Although the energy fluxes were higher for spring tides and were strongly influenced by winds, the energy dissipation was controlled by bed shear stresses and vertical dispersion. The significance of this energy dissipation was that it destabilized the water column, which resulted in a weakly stratified system with implications on water quality. At a subtidal scale, the residual water volume exchange was the result of the combined effects of the neap/spring tides, wind and waves, whereas tides were dominant at the tidal scale.

  13. Influence of oscillating flow on hyporheic zone development.

    Science.gov (United States)

    Maier, Herb S; Howard, Ken W F

    2011-01-01

    The hyporheic zone is an ecologically important ecotone that describes the extent to which nutrient-rich surface waters penetrate the shallow subsurface adjacent to a flowing surface water body. Although steady-state models satisfactorily explain the incursion of surface water into the subsurface as a function of head gradients developed across streambed riffles, they fail to account for the depth that surface water is observed to penetrate the subsurface or for the extent to which the hyporheic zone develops adjacent to the stream channel. To investigate these issues, transient flow modeling has been conducted at the riffle scale and supported by data for an instrumented site in northern Ontario where stream-stage fluctuations are strictly regulated. Model results show that daily stream-stage fluctuations between 0.6 and 4 m produce oscillating solute flow paths that typically reduce residence times of water and solutes in the hyporheic zone from 60 days or more under steady-state conditions to less than 1 day. Furthermore, similar stream-stage fluctuations increase the depth that solutes pervade the subsurface and banks lateral to the stream from around 1 m under steady-state conditions to as much as 2 and 10 m, respectively. The results demonstrate that the transient flow conditions triggered in the subsurface by variable stream stage can exert a strong influence on hyporheic zone development and have important implications for the hyporheos. The results are especially important for hyporheic communities that may survive gradual changes to their living conditions by migrating to more hospitable aquatic habitats, but are unable to respond to rapid changes provoked by more extreme hydrological events. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

  14. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    CERN Document Server

    Rivera, Jose Luis; Guerra-Gonzalez, Roberto

    2015-01-01

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect ...

  15. Population dynamics of subtidal blue mussels Mytilus edulis and the impact of cultivation

    NARCIS (Netherlands)

    Capelle, J.; Stralen, Van Marnix; Wijsman, J.W.M.; Herman, Peter M.J.; Smaal, A.C.

    2017-01-01

    Fishery on subtidal mussel beds and subsequent relying on culture plots in the same system is a common practice in bottom mussel culture. We address factors that determine the population dynamics of subtidal blue mussels Mytilus edulis L. and to what extent total (natural plus cultured) subtidal

  16. A symbiotic shell-encrusting bryozoan provides subtidal whelks with ...

    African Journals Online (AJOL)

    The subtidal whelk Burnupena papyracea co-occurs with a voracious predator, the rock lobster Jasus lalandii, in situations where other potential prey are largely eliminated. The survival of B. papyracea has been ascribed to a symbiotic bryozoan, Alcyonidium nodosum, which characteristically encrusts the shells of this ...

  17. Guidelines for the study of the epibenthos of subtidal environments

    NARCIS (Netherlands)

    Rees, H.L.; Bergman, M.J.N.; Birchenough, S.N.R.; Borja, A.; Boois, de I.J.

    2009-01-01

    These Guidelines for the Study of the Epibenthos of Subtidal Environments document a range of sampling gears and procedures for epibenthos studies that meet a variety of needs. The importance of adopting consistent sampling and analytical practices is highlighted. Emphasis is placed on ship‐based

  18. Subtidal marine algae of the Dwaraka Coast (Gujarat)

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Deshmukhe, G.V.

    A total of 35 marine algal species were recorded during a survey of the subtidal flora of Dwaraka, Gujrat, India. Maximum number of species were found at 5-8 m depth. Red algal species were dominant (20), followed by green (8) and brwon (7...

  19. Patterns in subtidal seaweed communities on coral-dominated reefs ...

    African Journals Online (AJOL)

    Subtidal seaweed communities of the northern coast of KwaZulu-Natal (KZN) have not been studied before. At Sodwana Bay, we tested the hypotheses that the seaweed communities would (1) differ floristically with depth, (2) be more species-rich in shallower water, (3) show similar biomasses within the depth range ...

  20. Hyporheic zone as a bioreactor: sediment heterogeneity influencing biogeochemical processes

    Science.gov (United States)

    Perujo, Nuria; Romani, Anna M.; Sanchez-Vila, Xavier

    2017-04-01

    Mediterranean fluvial systems are characterized by frequent periods of low flow or even drought. During low flow periods, water from wastewater treatment plants (WWTPs) is proportionally large in fluvial systems. River water might be vertically transported through the hyporheic zone, and then porous medium acts as a complementary treatment system since, as water infiltrates, a suite of biogeochemical processes occurs. Subsurface sediment heterogeneity plays an important role since it influences the interstitial fluxes of the medium and drives biomass growing, determining biogeochemical reactions. In this study, WWTP water was continuously infiltrated for 3 months through two porous medium tanks: one consisting of 40 cm of fine sediment (homogeneous); and another comprised of two layers of different grain size sediments (heterogeneous), 20 cm of coarse sediment in the upper part and 20 cm of fine one in the bottom. Several hydrological, physicochemical and biological parameters were measured periodically (weekly at the start of the experiment and biweekly at the end). Analysed parameters include dissolved nitrogen, phosphorus, organic carbon, and oxygen all measured at the surface, and at 5, 20 and 40 cm depth. Variations in hydraulic conductivity with time were evaluated. Sediment samples were also analysed at three depths (surface, 20 and 40 cm) to determine bacterial density, chlorophyll content, extracellular polymeric substances, and biofilm function (extracellular enzyme activities and carbon substrate utilization profiles). Preliminary results suggest hydraulic conductivity to be the main driver of the differences in the biogeochemical processes occurring in the subsurface. At the heterogeneous tank, a low nutrient reduction throughout the whole medium is measured. In this medium, high hydraulic conductivity allows for a large amount of infiltrating water, but with a small residence time. Since some biological processes are largely time-dependent, small water

  1. Decapod assemblages in subtidal and intertidal zones—Importance of scuba diving as a survey technique in tropical reefs, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno Welter Giraldes

    2015-01-01

    Full Text Available Decapods play a crucial role within the reef ecosystem and the development of scuba diving as a survey tool has allowed researchers the opportunity to study the decapod–reef relationship more comprehensively. The present study describes the differences in decapod assemblages in intertidal and subtidal zones at a tropical coastal reef system in the southwestern Atlantic Ocean and reports the importance of scuba diving as a survey technique. A total of 71 decapods were recorded during the research; 42 in the intertidal zone mainly formed by small endobenthic species and 39 in the subtidal zone primarily large species only 10 were found to frequent both sample zones. The study extends the range of Brachycarpusholthuisi Fausto Filho 1966 in Brazil; and also demonstrates how scuba diving can be used to complement traditional methodologies and vice versa. The research shows the advantages of using scuba diving when studying trade endangered decapods, as the methodology allows access to cryptic habitats such as reef caves and underwater cavities which were inaccessible when using traditional techniques. In conclusion scuba diving represents a revolutionary non-destructive survey tool allowing the researcher to directly access a specific decapod assemblage in fragile reef environments and in protected marine areas.

  2. Influence of fault slip on mining-induced pressure and optimization of roadway support design in fault-influenced zone

    OpenAIRE

    Wang, Hongwei; Jiang, Yaodong; Xue, Sheng; Mao, Lingtao; Lin, Zhinan; Deng, Daixin; Zhang, Dengqiang

    2016-01-01

    This paper presents an investigation on the characteristics of overlying strata collapse and mining-induced pressure in fault-influenced zone by employing the physical modeling in consideration of fault structure. The precursory information of fault slip during the underground mining activities is studied as well. Based on the physical modeling, the optimization of roadway support design and the field verification in fault-influenced zone are conducted. Physical modeling results show that, du...

  3. Role of algal eukaryotes in subtidal columnar stromatolite formation

    OpenAIRE

    Awramik, Stanley M.; Riding, Robert

    1988-01-01

    Columnar stromatolites were abundant and widespread in the Proterozoic but are exceedingly rare in modern seas. Consequently, the stromatolites at Hamelin Pool in Shark Bay, Western Australia, have been widely interpreted as unique modern analogs of ancient stromatolites constructed by complex communities of cyanobacteria. However, the Shark Bay columnar stromatolites contain sediment that is unusually coarse for stromatolites both ancient and modern, and the subtidal columnar stromatolites h...

  4. Macrobenthos of the subtidal Wadden Sea: revisited after 55 years

    Science.gov (United States)

    Riesen, W.; Reise, K.

    1982-12-01

    During the years 1923 1926 Hagmeier & Kändler (1927) sampled the macrofauna of subtidal shallows and channels of the Wadden Sea close to the Island of Sylt (German Bight, North Sea). Reinvestigating this study area in 1980, a substantially altered faunal composition was recorded. An approach is made to quantify the comparison in terms of abundance, species richness and diversity of invertebrate taxa. Human interference is assumed to be responsible for the major changes. Natural oyster beds have been overexploited and the local population of Ostrea edulis has been driven to extinction. Subsequently, mussels (Mytilus edulis) spread in the entire region, promoted by shell fishery. Particularly barnacles and many polychaetes took advantage of the expansion of mussel banks which is substantiated by correlation analysis. Reefs of the colonial polychaete Sabellaria spinulosa stood in the way of shrimp trawling and became destroyed together with the associated fauna. A subtidal Zostera marina bed was wiped out in 1934 by a natural epidemic disease but never succeeded in reestablishing itself. The associated fauna disappeared. Large epibenthic predators and scavengers (crabs, snails and starfish) survived all these changes. The total number of species remained approximately at the same level but molluscs experienced losses and polychaetes diversified. Overall abundance increased with a disproportionately large share of a few species (Mytilus edulis, Balanus crenatus, Cerastoderma edule, Scoloplos armiger). The subtidal fauna of the Wadden Sea proved to be vulnerable to human disturbance; thus, the present community can no longer be viewed as the outcome of entirely natural processes.

  5. Emergence Rhythms of Subtidal Small Invertebrates in the Subtropical Sea : Nocturnal Patterns and Variety in the Synchrony with Tidal and Lunar Cycles(Ecology)

    OpenAIRE

    Masayuki, Saigusa; Kazushi, Oishi; Department of Biology, Faculty of Science, Okayama University; Department of Biology, Faculty of Science, Okayama University

    2000-01-01

    The subtidal zones near the shore are inhabited by many small invertebrates, including benthos and plankton. To characterize their emergence in the water column with regards to day/night, tidal, and lunar cycles, field investigations were carried out at the subtropical island (Iriomote-jima), Okinawa Prefecture. By use of two impeller pumps installed in both surface and bottom waters, invertebrates were sampled continuously for 23 days. Although most patterns were much the same between the su...

  6. Subtidal Bathymetric Changes by Shoreline Armoring Removal and Restoration Projects

    Science.gov (United States)

    Wallace, J.

    2016-12-01

    The Salish Sea, a region with a diverse coastline, is altered by anthropogenic shoreline modifications such as seawalls. In recent years, local organizations have moved to restore these shorelines. Current research monitors the changes restoration projects have on the upper beach, lower beach, and intertidal, however little research exists to record possible negative effects on the subtidal. The purpose of this research is to utilize multibeam sonar bathymetric data to analyze possible changes to the seafloor structure of the subtidal in response to shoreline modification and to investigate potential ecosystem consequences of shoreline alteration. The subtidal is home to several species including eelgrass (Zostera marina). Eelgrass is an important species in Puget Sound as it provides many key ecosystem functions including providing habitat for a wide variety of organisms, affecting the physics of waves, and sediment transport in the subtidal. Thus bathymetric changes could impact eelgrass growth and reduce its ability to provide crucial ecosystem services. Three Washington state study sites of completed shoreline restoration projects were used to generate data from areas of varied topographic classification, Seahurst Park in Burien, the Snohomish County Nearshore Restoration Project in Everett, and Cornet Bay State Park on Whidbey Island. Multibeam sonar data was acquired using a Konsberg EM 2040 system and post-processed in Caris HIPS to generate a base surface of one-meter resolution. It was then imported into the ArcGIS software suite for the generation of spatial metrics. Measurements of change were calculated through a comparison of historical and generated data. Descriptive metrics generated included, total elevation change, percent area changed, and a transition matrix of positive and negative change. Additionally, pattern metrics such as, surface roughness, and Bathymetric Position Index (BPI), were calculated. The comparison of historical data to new data

  7. Influence of fault slip on mining-induced pressure and optimization of roadway support design in fault-influenced zone

    Directory of Open Access Journals (Sweden)

    Hongwei Wang

    2016-10-01

    Full Text Available This paper presents an investigation on the characteristics of overlying strata collapse and mining-induced pressure in fault-influenced zone by employing the physical modeling in consideration of fault structure. The precursory information of fault slip during the underground mining activities is studied as well. Based on the physical modeling, the optimization of roadway support design and the field verification in fault-influenced zone are conducted. Physical modeling results show that, due to the combined effect of mining activities and fault slip, the mining-induced pressure and the extent of damaged rock masses in the fault-influenced zone are greater than those in the uninfluenced zone. The sharp increase and the succeeding stabilization of stress or steady increase in displacement can be identified as the precursory information of fault slip. Considering the larger mining-induced pressure in the fault-influenced zone, the new support design utilizing cables is proposed. The optimization of roadway support design suggests that the cables can be anchored in the stable surrounding rocks and can effectively mobilize the load bearing capacity of the stable surrounding rocks. The field observation indicates that the roadway is in good condition with the optimized roadway support design.

  8. Wave and sediment dynamics along a shallow subtidal sandy beach inhabited by modern stromatolites.

    Science.gov (United States)

    Eckman, J E; Andres, M S; Marinelli, R L; Bowlin, E; Reid, R P; Aspden, R J; Paterson, D M

    2008-01-01

    To help define the habitat of modern marine stromatolites, wave-dominated flow and sediment transport were studied in the shallow subtidal region (1-2 m depth) along the slightly concave, windward face of Highborne Cay, Exuma, Bahamas - the only face of the cay that includes a population of stromatolites concentrated near the region of highest curvature of the beach. Wave energy impacting this island's most exposed beach was driven by local wind forcing which increases largely in response to the passage of atmospheric disturbances that typically affect the region for periods of a few days. Although some wave energy is almost always noted (maximum horizontal orbital speeds at the bottom are rarely Stromatolites, which are largely restricted to the shoreward side of a shallow platform reef, are sheltered by the reef beyond which wave speeds are one to four times higher (depending on tidal stage). Moreover, stromatolite populations are predominantly found along a region of this wave-exposed beach that experiences comparatively reduced wave energy because of the curved morphology of the island's face. Maximum wave speeds are 1.4 to 2 times higher along more northern sections of the beach just beyond the locus of stromatolite populations. A quantitative model of sediment transport was developed that accurately predicted accumulation of suspended sediment in sediment traps deployed in the shallow subtidal zone along this beach. This model, coupled with in situ wave records, indicates that gross rates of suspended sediment deposition should be two to three times higher northward of the main stromatolite populations. Regions of the beach containing stromatolites nevertheless should experience significant rates of gross suspended sediment deposition averaging 7-10 g cm(-2) day(-1) ( approximately 4-6 cm day(-1)). Results suggest that one axis of the habitat of modern marine stromatolites may be defined by a comparatively narrow range of flow energy and sediment transport

  9. Factors Influencing Antenatal Care Service Utilization in Hadiya Zone

    African Journals Online (AJOL)

    Ethiopian Journal of Health Sciences ... Therefore, the objective of this study was to explore factors influencing antenatal care services utilization in Southern Ethiopia. ... Promoting information, education and communication in the community is recommended to favorably affect the major predictors of antenatal care service ...

  10. Influence of limnological zones on the spatial distribution of fish assemblages in three Brazilian reservoirs

    Directory of Open Access Journals (Sweden)

    Bárbara Becker

    2015-09-01

    Full Text Available Reservoirs can have both positive and negative effects on differing fish species depending on the species concerned and reservoir morphology, flow regime, and basin location.  We assessed the influence of limnological zones on the ichthyofauna of three large Neotropical reservoirs in two different river basins. We sampled fish through use of gill nets set at 40 systematically selected sites on each reservoir. We used satellite images, algae, and suspended solids concentrations to classify those sites as lacustrine or riverine. We observed significant differences in assemblage composition between riverine and lacustrine zones of each reservoir. We either tested if the same region (lacustrine or riverine showed the same patterns in different reservoirs. In São Simão, the riverine zone produced greater abundances of native species, long-distance migratory species, diversity, and richness, whereas the lacustrine zone supported greater total and non-native species abundances. Conversely, in Três Marias, the riverine zone supported greater total and non-native species abundances, whereas the others traits evaluated did not differ significantly between zones. Only lacustrine sites occurred in Volta Grande Reservoir. The same zones in the three reservoirs usually had significantly different patterns in the traits evaluated. The differences in spatial patterns observed between reservoirs could be explained partly by the differing morphologies (complex versus linear, the differential influence of tributaries of each reservoir and basin positions (presence or absence of upstream dams of the reservoirs.

  11. Trophic Resources to Subtidal Suspension Feeders in Kelp Ecosystems

    Science.gov (United States)

    Yorke, C.; Miller, R. J.; Page, H. M.; Shears, N. T.; Hanns, B. J.

    2016-02-01

    Kelps are highly productive, yet little is known about the fates of kelp primary production. Traditionally, kelps have been assumed to form the base of kelp forest food webs. This assumption extended naturally to suspension feeders, which can comprise up to 80% of the animal biomass in kelp forests and have been hypothesized to consume small particles of kelp sloughing off the extensive surface canopy. Subtidal suspension feeders graze on abundant phytoplankton, but if kelp detritus is a viable food source for suspension feeders, it could be particularly significant during seasonal declines in nutrient concentrations and consequently phytoplankton production. However, direct evidence of kelp detritus assimilation by suspension feeders is scarce: most inference has been based on natural abundance stable isotope analyses which are often based on untested assumptions. To more directly address this problem, we measured kelp detrital sloughing rates and ran experiments to assess kelp particle availability and suspension feeder utilization of naturally occurring kelp detritus when phytoplankton are either abundant or scarce. We have also begun preliminary work to look at alternate pathways for kelp utilization by suspension feeders and detritivores in kelp forests. The bulk of these studies were conducted with two kelp species: Ecklonia radiata in northeastern New Zealand and with Macrocystis pyrifera in Santa Barbara, California. The results of these studies indicate that phytoplankton rather than kelp detritus are the primary food source for subtidal suspension feeders.

  12. Influence of controlling vibrations on heat transfer in floating zone crystal growth*

    Science.gov (United States)

    Fedyushkin, A. I.

    The crystal growth processes of monocrystals are strongly vibrational sensitive systems and in particular it concerns to a floating zone method as presence of a free surface and two fronts of crystallization and melting that aggravate it The given work is devoted to numerical investigations of the influence of controlling vibrations on heat transfer during crystal growth by floating zone technique Normal and weightless environment conditions are considered Mathematical simulation is performed on the numerical solutions of basis unsteady Navier-Stokes equations for incompressible fluid flows and energy equation 2D axisymmetric geometry was used in model Marangoni convection and radiation condition on the curvature free surface were taken in account The calculations of the shape of a free surface of a liquid zone and influences on it of a corner of wetting force of weight and size of factor of a superficial tension are carried out The simulations of convective heat transfer for real curvature free surface of a liquid zone with and without the taking into account of the following factors parameters of radiation rotations natural and Marangoni convection and vibrations are carried out The given calculations are carried out for semiconductors melts with Prandtl number Pr 1 and for oxides Pr 1 The influence of vibrations of a crystal on melt flow and on the wide of dynamic and thermal boundary layers at melt-crystal interface is studied The action of vibrations on an enhancement of heat fluxes at the melt crystal interface is shown

  13. Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon.

    Science.gov (United States)

    Kang, Chang-Keun; Park, Hyun Je; Choy, Eun Jung; Choi, Kwang-Sik; Hwang, Kangseok; Kim, Jong-Bin

    2015-01-01

    We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB), phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰) of offshore consumers, a broad δ13C range (-18 to -12‰) of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, δ13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical δ13C range with many intertidal foragers (including crustaceans and fish), overlapping with the range of MPB. In contrast, δ13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.

  14. Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon.

    Directory of Open Access Journals (Sweden)

    Chang-Keun Kang

    Full Text Available We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB, phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰ of offshore consumers, a broad δ13C range (-18 to -12‰ of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, δ13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical δ13C range with many intertidal foragers (including crustaceans and fish, overlapping with the range of MPB. In contrast, δ13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.

  15. Cascading effects of ocean acidification in a rocky subtidal community.

    Directory of Open Access Journals (Sweden)

    Valentina Asnaghi

    Full Text Available Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae and their grazers (sea urchins. Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness. There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from

  16. Cascading effects of ocean acidification in a rocky subtidal community.

    Science.gov (United States)

    Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

    2013-01-01

    Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to

  17. Subtidal food thieves: interactions of four invertebrate kleptoparasites with the sea star Leptasterias polaris.

    Science.gov (United States)

    Morissette; Himmelman

    2000-10-01

    We used time-lapse underwater video systems in the subtidal zone of the Mingan Islands, eastern Canada, to examine behavioural interactions of four kleptoparasites with the sea star Leptasterias polaris when it was feeding on infaunal (buried) clams. Departures of L. polaris from its prey coincided with interactions with kleptoparasites in 10 out of 10 filmed feeding bouts on the large clam Spisula polynyma, compared with only four out of 10 of filmed bouts on the smaller clam Mya truncata. The sea star's abandoning of the prey was most often caused by interactions with another sea star, Asterias vulgaris, a potential predator. The whelk (a carnivorous snail), Buccinum undatum, and the crabs Hyas araneus and Cancer irroratus, also kleptoparasitized L. polaris, especially when A. vulgaris was present. Comparisons of feeding bouts in the presence and absence of kleptoparasites showed that at least 10.4% of the prey mass captured by L. polaris was lost to kleptoparasites. Simultaneous current meter data showed that the movement of A. vulgaris and B. undatum to sites where L. polaris was feeding on S. polynyma was upstream, suggesting chemodetection of food odours. Crabs in the vicinity may also use visual cues. Leptasterias polaris is the only carnivore that can efficiently extract large clams from the sediments and therefore its foraging may supply a substantial part of the diet of kleptoparasites. Copyright 2000 The Association for the Study of Animal Behaviour.

  18. Preliminary investigation into the zone of support influence and stable span between support units.

    CSIR Research Space (South Africa)

    Daehnke, A

    1999-10-01

    Full Text Available ).........................................................................................................24 Figure 2.2.4 Schematic showing stress trajectories for fractures orientated 90°. ........................25 Figure 2.2.5 Rock mass instability due to shear failure at the abutments............ ....................26 Figure 2.2.6 Buckling failure... parameters governing the zones of support influence.. ..................................................................................................65 Figure 4.3.1 Principal stress trajectories through a homogeneous hangingwall beam loaded by a single...

  19. Use of side-scan sonar for estimations of Crassostrea brasiliana (Lamarck, 1819 stocks in subtidal banks on the south coast of Brazil

    Directory of Open Access Journals (Sweden)

    Gisela Geraldine Castilho Westphal

    2016-03-01

    Full Text Available Abstract Uncontrolled extractivism has led to a worldwide reduction in oyster stocks. The use of new and more efficient management tools for impacted environments must increase. The application of such tools requires previous biological and environmental knowledge of the resident populations of these bivalve mollusks. Technical difficulties are usually associated with studies of submerged oyster banks, and these difficulties result in a considerable lack of biological data on the oysters that inhabit subtidal zones. This study aimed to survey Crassostrea brasiliana (also known as C. gasar stocks in submerged banks and to evaluate a method with which to measure the extent of the banks and identify and quantify the oysters in the banks with the use of side-scan sonar. This study was conducted on 10 oysters banks located in the subtidal zone of Guaratuba Bay, on the south coast of Brazil. The prospection of all these banks was later validated by diving, and oyster samples (n = 20/bank were collected for species identification with a molecular method. Only one bank contained oysters that were generically classified as Crassostrea sp.; those in the remaining banks being identified as C. brasiliana. The prospected banks contained oysters of various sizes (average 1.5 m, n = 1,107 that were heterogeneously scattered in the riverbeds. The total number of oysters in the 10 sampled banks was estimated to be 21,159.13 oysters or 1 oyster/4.5 m², which represents a low oyster density in the study site. The results validate the use of side-scan sonar as an efficient means with which to prospect for oysters in banks located within subtidal zones.

  20. Succession in subtidal macrofouling assemblages of a Patagonian harbour (Argentina, SW Atlantic)

    National Research Council Canada - National Science Library

    Rico, Alicia; Peralta, Roxana; López Gappa, Juan

    2012-01-01

    Subtidal fouling assemblages usually consist of short-lived organisms. Colonisation sequences on man-made structures may thus be greatly affected by the temporal and spatial variability of propagule supply...

  1. Estuarine, intertidal and subtidal wetland habitat types in Klag Bay, Chichagof Island, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Six major estuarine intertidal and subtidal wetland habitat types were identified within the inner basin of Klag Bay. These habitat types are mapped in Fig. 3. The...

  2. NODC Standard Format Intertidal/Subtidal (F100) Data (1974-1979) (NODC Accession 0014193)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data type is used to support physical and biological studies of the intertidal/subtidal regime. There are eight data record types to: 1) identify the station,...

  3. The Intramolecular Pressure and the Extension of the Critical Point’s Influence Zone on the Order Parameter

    Directory of Open Access Journals (Sweden)

    Jose Luis Rivera

    2015-01-01

    Full Text Available The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone covers up to hundreds of degrees below the critical temperature. Here we show that, for ethane, the experimental critical influence zone covers a wide zone of tens of degrees (below the critical temperature down to a transition temperature, at which the apparent critical influence zone vanishes, and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase, using a simple molecular potential. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, Molecular Dynamics simulations reveal that the experimentally observed wide extension of the critical influence zone is the result of a vapor-like effect due to low bulk liquid phase densities.

  4. Influence of cluster zone leaf removal on Pinot noir grape chemical and volatile composition.

    Science.gov (United States)

    Feng, Hui; Yuan, Fang; Skinkis, Patricia A; Qian, Michael C

    2015-04-15

    The influence of cluster-zone leaf removal on Pinot noir vine growth and fruit chemical and volatile composition was investigated in 3 years. Different severities of leaf removal (0%, 50%, 100%) were imposed during the pea-size stage of development from the cluster zone. Results show that cluster-zone leaf removal had little influence on vine growth, crop load, or grape maturity in terms of total soluble solids (TSS), pH or titratable acidity (TA) at harvest. However, 100% leaf removal resulted in higher concentrations of quercetin glycoside in grapes compared to 0% leaf removal. The 100% leaf removal also increased concentrations of petunidin- and malvidin-3-monoglucoside anthocyanins in two out of 3 years (2010 and 2012) by an average of 62% and 53%, respectively. In addition, 100% leaf removal resulted in higher concentrations of β-damascenone, and some bound-form terpenoids. The increases in β-damascenone were positively correlated to the increased sunlight exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Influence of calcite on uranium(VI) reactive transport in the groundwater-river mixing zone.

    Science.gov (United States)

    Ma, Rui; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John; Zheng, Chunmiao

    2014-01-01

    Calcite is an important, relatively soluble mineral phase that can affect uranium reactive transport in subsurface sediments. This study was conducted to investigate the distribution of calcite and its influence on uranium adsorption and reactive transport in the groundwater-river mixing zone of the Hanford 300A site, Washington State. Simulations using a two-dimensional (2D) reactive transport model under field-relevant hydrological and hydrogeochemical conditions revealed the development of a calcite reaction front through the mixing zone as a result of dynamic groundwater-river interactions. The calcite concentration distribution, in turn, affected the concentrations of aqueous carbonate and calcium, and pH through dissolution, as river waters intruded and receded from the site at different velocities in response to stage changes. The composition variations in groundwater subsequently influenced uranium mobility and discharge rates into the river in a complex fashion. The results implied that calcite distribution and concentration are important variables that need to be quantified for accurate reactive transport predictions of uranium, especially in dynamic groundwater-river mixing zones. © 2013.

  6. Interpretation of benthic foraminiferal stable isotopes in subtidal estuarine environments

    Directory of Open Access Journals (Sweden)

    Y.-M. Paulet

    2009-11-01

    Full Text Available Here we present a novel approach for the interpretation of stable isotope signatures recorded in benthic foraminifera from subtidal estuarine environments. The stable isotopic composition (δ18O and δ13C of living Ammonia tepida and Haynesina germanica is examined at four stations in the Auray River estuary (Gulf of Morbihan, France sampled in two contrasting seasons, spring 2006 and winter 2007. Comparing benthic foraminiferal δ18O measurements with theoretical oxygen isotopic equilibrium values, calculated on the basis of water temperature and salinity measurements in the upper and lower estuary, i.e., T-S-δ18Oeq. diagrams, strongly suggests that foraminiferal faunas sampled at the four stations calcified during different periods of the year. This interpretation can be refined by using the benthic foraminiferal δ13C, which is mainly determined by the mixing of sea and river water. In the upper estuary foraminifera mainly calcified in early spring and winter, whereas in the lower estuary calcification mainly took place in spring, summer and autumn. This new method provides insight into the complexity of estuarine benthic foraminiferal stable isotope records. In addition, it can also be used to obtain new information on preferred calcification periods of benthic foraminiferal taxa in different parts of the estuary.

  7. The influence of distance between heat sources in hybrid welded plate on fusion zone geometry

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2011-04-01

    Full Text Available Results of numerical analysis into temperature field in hybrid laser-arc welding process with motion of liquid material taken intoaccount are presented in this study. On the basis of obtained results the influence of the distance between the arc foot point and the laserbeam focal point on the shape and size of fusion zone in hybrid butt welded plate. Temperature field was calculated on the basis ofsolution of transient heat transfer equation. The solution of Navier-Stokes equation allowed for simulation of fluid flow in the fusion zone.Fuzzy solidification front was assumed in calculations with linear approximation of solid fraction in solid-liquid region where liquidmaterial flow through porous medium is taken into consideration. Numerical solution algorithms were developed for three-dimensionalproblem. Established numerical model of hybrid welding process takes into account different electric arc and laser beam heat sourcespower distributions.

  8. Influence of Topography on Root Processes in the Shale Hills-Susquehanna Critical Zone Observatory

    Science.gov (United States)

    Eissenstat, D. M.; Orr, A. S.; Adams, T. S.; Chen, W.; Gaines, K.

    2015-12-01

    Topography can strongly influence root and associated mycorrhizal fungal function in the Critical Zone. In the Shale Hills-Susquehanna Critical Zone Observatory (SSCZO), soil depths range from more than 80 cm deep in the valley floor to about 25 cm on the ridge top. Tree height varies from about 28 m tall at the valley floor to about 17 m tall at the ridge top. Yet total absorptive root length to depth of refusal is quite similar across the hillslope. We find root length density to vary as much at locations only 1-2 m apart as at scales of hundreds of meters across the catchment. Tree community composition also varies along the hillslope, including tree species that vary widely in thickness of their absorptive roots and type of mycorrhiza (arbuscular mycorrhizal and ectomycorrhizal). Studies of trees in a common garden of 16 tree species and in forests near SSCZO indicate that both root morphology and mycorrhizal type can strongly influence root foraging. Species that form thick absorptive roots appear more dependent on mycorrhizal fungi and thin-root species forage more by root proliferation. Ectomycorrhizal trees show more variation in foraging precision (proliferation in a nutrient-rich patch relative to that in an unenriched patch) of their mycorrhizal hyphae whereas AM trees show more variation in foraging precision by root proliferation, indicating alternative strategies among trees of different mycorrhizal types. Collectively, the results provide insight into how topography can influence foraging belowground.

  9. Disentangling the influence of cell phone usage in the dilemma zone: An econometric approach.

    Science.gov (United States)

    Eluru, Naveen; Yasmin, Shamsunnahar

    2016-11-01

    This paper focuses on developing an analysis framework to study the impact of cell phone treatment (cell phone type and call status) on driver behavior in the presence of a dilemma zone. Specifically, we examine how the treatment influences the driver maneuver decision at the intersection (stop or cross) and the eventual success of the maneuver. For a stop maneuver, success is defined as stopping before the stop line. Similarly, for a cross maneuver, success is defined as clearing the intersection safely before the light turns red. The eventual success or failure of the driver's decision process is dependent on the factors that affected the maneuver decision. Hence it is important to recognize the interconnectedness of the stop or cross decision with its eventual success (or failure). Toward this end, we formulate and estimate a joint framework to analyze the stop/cross decision with its eventual success (or failure) simultaneously. The study is conducted based on driving simulator data provided online for the 2014 Transportation Research Board Data Contest at http://depts.washington.edu/hfsm/upload.php. The model is estimated to analyze drivers' behavior at the onset of yellow by employing exogenous variables from three broad categories: driver characteristics, cell phone attributes and driving attributes. We also generate probability surfaces to identify dilemma zone distribution associated with different cell phone treatment types. The plots clearly illustrate the impact of various cellphone treatments on driver dilemma zone behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Hyporheic zone influences on concentration-discharge relationships in a headwater sandstone stream

    Science.gov (United States)

    Hoagland, Beth; Russo, Tess A.; Gu, Xin; Hill, Lillian; Kaye, Jason; Forsythe, Brandon; Brantley, Susan L.

    2017-06-01

    Complex subsurface flow dynamics impact the storage, routing, and transport of water and solutes to streams in headwater catchments. Many of these hydrogeologic processes are indirectly reflected in observations of stream chemistry responses to rain events, also known as concentration-discharge (CQ) relations. Identifying the relative importance of subsurface flows to stream CQ relationships is often challenging in headwater environments due to spatial and temporal variability. Therefore, this study combines a diverse set of methods, including tracer injection tests, cation exchange experiments, geochemical analyses, and numerical modeling, to map groundwater-surface water interactions along a first-order, sandstone stream (Garner Run) in the Appalachian Mountains of central Pennsylvania. The primary flow paths to the stream include preferential flow through the unsaturated zone ("interflow"), flow discharging from a spring, and groundwater discharge. Garner Run stream inherits geochemical signatures from geochemical reactions occurring along each of these flow paths. In addition to end-member mixing effects on CQ, we find that the exchange of solutes, nutrients, and water between the hyporheic zone and the main stream channel is a relevant control on the chemistry of Garner Run. CQ relationships for Garner Run were compared to prior results from a nearby headwater catchment overlying shale bedrock (Shale Hills). At the sandstone site, solutes associated with organo-mineral associations in the hyporheic zone influence CQ, while CQ trends in the shale catchment are affected by preferential flow through hillslope swales. The difference in CQ trends document how the lithology and catchment hydrology control CQ relationships.

  11. Conflicts in Africa and Major Powers: Proxy Wars, Zones of Influence or Provocative Instability

    Directory of Open Access Journals (Sweden)

    Jerry Rowlings Tafotie

    2016-12-01

    Full Text Available The article analyses the different nature of conflicts that have occurred in Africa since the end of Cold War. A special attention is given to the role of external factors in the process of conflict evolution and the escalation of violence on the African continent. In effect, this paper demonstrates through a critical examination of the meaning of proxy war as, zone of influence or provocation of instability as a strategy and an analysis of its employment by the United States and China, France etc. in Africa. The new potential confrontation between the United States and China as in Sudan, France in its former coloniesis not only based on a clash of world views about the structure and nature of international relations and security but largely over the control of strategically vital energy resources based in Africa. The authors conclude that this ultimately creates permanent tensions or bitter conflicts between the actors and African populations as a factor that have negative impact on the peace and stability of continent. According to the context of superpower conflict strategies, this paper critically examines, zone of influence, provoking of instability or proxy war as a viable national strategy of nuclear armed great powers in advancing and/or defending their global national interests in a bipolar/multipolar international system.

  12. Influence of Local Zones of Intensive Heat Transfer on Thermal Regime of Heat Supply Objects

    Directory of Open Access Journals (Sweden)

    Maksimov Vyacheslav I.

    2015-01-01

    Full Text Available The results of mathematical simulation of conjugate heat transfer for heat supply object are represented. The turbulent regime of air motion in a closed cavity with the enclosing walls from reinforced concrete and glass is examined. On the outer boundary, which includes window aperture, the conditions of convective-radiation heat exchange with environment are realized. Is solved the system of the dimensionless equations within the framework of thermal conductivity model for the solid walls and Navier-Stokes for the gas. The influence of the local zones of intensive heat transfer on the thermal regime of the heat supply objects is established. Are determined the values of the dimensionless heat exchange coefficient on division border “air - wall”. The analysis of the values of mean temperatures of the solution region is carried out.

  13. Influence of foveal distractors on saccadic eye movements: a dead zone for the global effect.

    Science.gov (United States)

    Vitu, Françoise; Lancelin, Denis; Jean, Alexandre; Farioli, Fernand

    2006-12-01

    Three experiments investigated the global effect with foveal distractors displayed in the same hemifield as more eccentric saccade targets. Distractors were x-letter strings of variable length and targets corresponded to the central letter of letter strings (e.g., 'xxxkxxx'). Results showed that only foveal distractors longer than four letters (about 1 degree) deviated the eyes in a center-of-gravity manner thus suggesting a dead zone for the global effect. Short distractors influenced the likelihood of small-amplitude saccades (less than about 1 degree) and the latency of longer saccades. The findings were interpreted based on the dissociation between fixation and saccadic neurons. Implications for eye movements in reading were discussed.

  14. Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene

    Science.gov (United States)

    Chase, Brian M.; Lim, Sophak; Chevalier, Manuel; Boom, Arnoud; Carr, Andrew S.; Meadows, Michael E.; Reimer, Paula J.

    2015-01-01

    South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene.

  15. Influence of neighbourhood information on 'Local Climate Zone' mapping in heterogeneous cities

    Science.gov (United States)

    Verdonck, Marie-Leen; Okujeni, Akpona; van der Linden, Sebastian; Demuzere, Matthias; De Wulf, Robert; Van Coillie, Frieke

    2017-10-01

    Local climate zone (LCZ) mapping is an emerging field in urban climate research. LCZs potentially provide an objective framework to assess urban form and function worldwide. The scheme is currently being used to globally map LCZs as a part of the World Urban Database and Access Portal Tools (WUDAPT) initiative. So far, most of the LCZ maps lack proper quantitative assessment, challenging the generic character of the WUDAPT workflow. Using the standard method introduced by the WUDAPT community difficulties arose concerning the built zones due to high levels of heterogeneity. To overcome this problem a contextual classifier is adopted in the mapping process. This paper quantitatively assesses the influence of neighbourhood information on the LCZ mapping result of three cities in Belgium: Antwerp, Brussels and Ghent. Overall accuracies for the maps were respectively 85.7 ± 0.5, 79.6 ± 0.9, 90.2 ± 0.4%. The approach presented here results in overall accuracies of 93.6 ± 0.2, 92.6 ± 0.3 and 95.6 ± 0.3% for Antwerp, Brussels and Ghent. The results thus indicate a positive influence of neighbourhood information for all study areas with an increase in overall accuracies of 7.9, 13.0 and 5.4%. This paper reaches two main conclusions. Firstly, evidence was introduced on the relevance of a quantitative accuracy assessment in LCZ mapping, showing that the accuracies reported in previous papers are not easily achieved. Secondly, the method presented in this paper proves to be highly effective in Belgian cities, and given its open character shows promise for application in other heterogeneous cities worldwide.

  16. A protected area influences genotype-specific survival and the structure of a Canis hybrid zone.

    Science.gov (United States)

    Benson, John F; Patterson, Brent R; Mahoney, Peter J

    2014-02-01

    It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4-7%). Furthermore, eastern wolves (hazard ratio = 3.5) and nonresidents (transients and dispersing animals, hazard ratio = 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely

  17. Devastating Transboundary Impacts of Sea Star Wasting Disease on Subtidal Asteroids.

    Science.gov (United States)

    Montecino-Latorre, Diego; Eisenlord, Morgan E; Turner, Margaret; Yoshioka, Reyn; Harvell, C Drew; Pattengill-Semmens, Christy V; Nichols, Janna D; Gaydos, Joseph K

    2016-01-01

    Sea star wasting disease devastated intertidal sea star populations from Mexico to Alaska between 2013-15, but little detail is known about its impacts to subtidal species. We assessed the impacts of sea star wasting disease in the Salish Sea, a Canadian / United States transboundary marine ecosystem, and world-wide hotspot for temperate asteroid species diversity with a high degree of endemism. We analyzed roving diver survey data for the three most common subtidal sea star species collected by trained volunteer scuba divers between 2006-15 in 5 basins and on the outer coast of Washington, as well as scientific strip transect data for 11 common subtidal asteroid taxa collected by scientific divers in the San Juan Islands during the spring/summer of 2014 and 2015. Our findings highlight differential susceptibility and impact of sea star wasting disease among asteroid species populations and lack of differences between basins or on Washington's outer coast. Specifically, severe depletion of sunflower sea stars (Pycnopodia helianthoides) in the Salish Sea support reports of major declines in this species from California to Alaska, raising concern for the conservation of this ecologically important subtidal predator.

  18. Devastating Transboundary Impacts of Sea Star Wasting Disease on Subtidal Asteroids.

    Directory of Open Access Journals (Sweden)

    Diego Montecino-Latorre

    Full Text Available Sea star wasting disease devastated intertidal sea star populations from Mexico to Alaska between 2013-15, but little detail is known about its impacts to subtidal species. We assessed the impacts of sea star wasting disease in the Salish Sea, a Canadian / United States transboundary marine ecosystem, and world-wide hotspot for temperate asteroid species diversity with a high degree of endemism. We analyzed roving diver survey data for the three most common subtidal sea star species collected by trained volunteer scuba divers between 2006-15 in 5 basins and on the outer coast of Washington, as well as scientific strip transect data for 11 common subtidal asteroid taxa collected by scientific divers in the San Juan Islands during the spring/summer of 2014 and 2015. Our findings highlight differential susceptibility and impact of sea star wasting disease among asteroid species populations and lack of differences between basins or on Washington's outer coast. Specifically, severe depletion of sunflower sea stars (Pycnopodia helianthoides in the Salish Sea support reports of major declines in this species from California to Alaska, raising concern for the conservation of this ecologically important subtidal predator.

  19. Subtidal Benthic Invertebrates Shifting Northward Along the U.S. Atlantic Coast

    Science.gov (United States)

    Numerous marine and terrestrial species have shifted their ranges poleward in response to warming from global climate change. However, few studies have examined range shifts of subtidal benthic communities in estuarine and nearshore waters. This study examined 20 years (1990&ndas...

  20. Transformation and fate of microphytobenthos carbon in subtropical shallow subtidal sands: A

    NARCIS (Netherlands)

    Oakes, J.M.; Eyre, B.D.; Middelburg, J.J.

    2012-01-01

    Microphytobenthos (MPB) in photic sediments are highly productive but the fate of this production remains uncertain. Over 33 d, tracing of C-13 from added bicarbonate in subtropical shallow subtidal sand showed rapid transfer of MPB-derived carbon to deeper sediment; below 2 cm (31% within 60 h) and

  1. Towards the declaration of a large marine protected area: a subtidal ...

    African Journals Online (AJOL)

    A subtidal marine ichthyofaunal survey was carried out on shallow reefs (1–30m deep) in the Pondoland region between the Mtamvuna River and Port St Johns in the Eastern Cape, South Africa. The purpose of this survey was to provide the baseline data required for the zonation of a large marine protected area proposed ...

  2. Tidal and subtidal flow patterns o a tropical continental shelf semi-insulated by coral reefs

    NARCIS (Netherlands)

    Tarya, A.; Hoitink, A.J.F.; Vegt, van der M.

    2010-01-01

    The present study sets out to describe the tidal and subtidal water motion at the Berau coastal shelf, which represents a tropical continental shelf area of variable width hosting a complex of barrier reefs along its oceanic edge. Moored and shipboard measurements on currents and turbulence were

  3. The subtidal gully fish community of the eastern cape and the role of ...

    African Journals Online (AJOL)

    The fish fauna of rocky subtidal gullies between Chelsea Point and Skoenmakerskop (South Africa) was sampled between October 1985 and September 1986 using rotenone to investigate the species composition and the importance of this habitat as a nursery area for marine linefish species. A total of 59 species ...

  4. Life-history regulation in the subtidal red alga Calliblepharis ciliata

    NARCIS (Netherlands)

    Molenaar, FJ; Venekamp, LAH; Breeman, AM

    The life-history strategy of the subtidal red alga Calliblepharis ciliata has been studied in the field and in laboratory culture. Bi-monthly observations on a C. ciliata population at Roscoff (Brittany, France) revealed a clear seasonal pattern. In April young plants appeared and grew through the

  5. Role of asymmetric tidal mixing in the subtidal dynamics of narrow estuaries

    NARCIS (Netherlands)

    Cheng, P.; de Swart, H.E.; Valle-Levinson, A.

    2013-01-01

    The role of asymmetric tidal mixing (ATM) in subtidal estuarine dynamics is investigated using a series of generic numerical experiments that simulate narrow estuaries under different stratification and external forcing conditions. The focus is on quantifying the characteristics of ATM-induced flow

  6. Flexibility of Physiological Traits Underlying Inter-Individual Growth Differences in Intertidal and Subtidal Mussels Mytilusgalloprovincialis.

    Directory of Open Access Journals (Sweden)

    María José Fernández-Reiriz

    Full Text Available Mussel seed (Mytilusgalloprovincialis gathered from the intertidal and subtidal environments of a Galician embayment (NW, Spain were maintained in the laboratory during five months to select fast (F and slow (S growing mussels. The physiological basis underlying inter-individual growth variations were compared for F and S mussels from both origins. Fast growing seemed to be a consequence of greater energy intake (20% higher clearance and ingestion rate and higher food absorption rate coupled with low metabolic costs. The enhanced energy absorption (around 65% higher resulted in 3 times higher Scope for Growth in F mussels (20.5±4.9 J h(-1 than S individuals (7.3±1.1 J h(-1. The higher clearance rate of F mussels appears to be linked with larger gill filtration surface compared to S mussels. Intertidal mussels showed higher food acquisition and absorption per mg of organic weight (i.e. mass-specific standardization than subtidal mussels under the optimal feeding conditions of the laboratory. However, the enhanced feeding and digestive rates were not enough to compensate for the initial differences in tissue weight between mussels of similar shell length collected from the intertidal and subtidal environments. At the end of the experiment, subtidal individuals had higher gill efficiency, which probably lead to higher total feeding and absorption rates relative to intertidal individuals.

  7. On the strength of oceanic fracture zones and their influence on the intraplate stress field

    Science.gov (United States)

    Bergman, Eric A.; Solomon, Sean C.

    1992-01-01

    We use the locations and source mechanisms of oceanic intraplate earthquakes to test the hypothesis that the strength of oceanic fracture zones is less than that of normal oceanic lithosphere. The 77 earthquakes selected for the study have well-determined focal mechanisms and epicenters in regions where fracture zones are well mapped. We have search for dependence of faulting style, fault orientation, or principal stress direction on the distance from the nearest fracture zone. If fracture zones were generally weaker than the surrounding lithosphere, one of the principal horizontal stresses would be oriented nearly perpendicular to the fracture zone; we find no evidence that principal stresses near fracture zones are oriented preferentially in this manner. There is a slight tendency for earthquakes to occur near fracture zones, and patterns of fault orientation and sense of slip support the view that differential cooling and horizontal contraction on fracture zones may contribute seismogenic stress.

  8. Influence of Gully Erosion Control on Amphibian and Reptile Communities within Riparian Zones of Channelized Streams

    Science.gov (United States)

    Riparian zones of streams in northwestern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Riparian gully formation has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used conservation practice for...

  9. The zone of influence of the subducting slab in the asthenospheric mantle

    Science.gov (United States)

    MacDougall, Julia G.; Jadamec, Margarete A.; Fischer, Karen M.

    2017-08-01

    Due to the multidisciplinary nature of combined geodynamics and shear wave splitting studies, there is still much to be understood in terms of isolating the contributions from mantle dynamics to the shear wave splitting signal, even in a two-dimensional (2-D) mantle flow framework. This paper investigates the viscous flow, lattice preferred orientation (LPO) development, and predicted shear wave splitting for a suite of buoyancy-driven subduction models using a non-linear rheology to shed light on the nature of the slab-driven asthenospheric flow and plate-mantle coupling. The slab-driven zone of influence in the mantle, LPO fabric, and resulting synthetic splitting are sensitive to slab strength and slab initial slab dip. The non-linear viscosity formulations leads to dynamic reductions in asthenospheric viscosity extending over 600 km into the mantle wedge and over 300 km behind the trench, with peak flow velocities occurring in models with a weaker slab and moderate slab dip. The olivine LPO fabric in the asthenosphere generally increases in alignment strength with increased proximity to the slab but can be transient and spatially variable on small length scales. The results suggest that LPO formed during initial subduction may persist into the steady state subduction regime. Vertical flow fields in the asthenosphere can produce shear wave splitting variations with back azimuth that deviate from the predictions of uniform trench-normal anisotropy, a result that bears on the interpretation of complexity in shear wave splitting observed in real subduction zones. Furthermore, the models demonstrate the corner flow paradigm should not be equated with a 2-D subduction framework.

  10. Influence of light zones on drivers' visual fixation characteristics and traffic safety in extra-long tunnels.

    Science.gov (United States)

    Yan, Ying; Wang, Xiaofei; Shi, Ludan; Liu, Haoxue

    2017-01-02

    Special light zone is a new illumination technique that promises to improve the visual environment and improve traffic safety in extra-long tunnels. The purpose of this study is to identify how light zones affect the dynamic visual characteristics and information perception of drivers as they pass through extra-long tunnels on highways. Thirty-two subjects were recruited for this study, and fixation data were recorded using eye movement tracking devices. A back-propagation artificial neural network was employed to predict and analyze the influence of special light zones on the variations in the fixation duration and pupil area of drivers. The analytic coordinates of focus points at different light zones were clustered to obtain different visual fixation regions using dynamic cluster theory. The findings of this study indicated that the special light zones had different influences on fixation duration and pupil area compared to other sections. Drivers gradually changed their fixation points from a scattered pattern to a narrow and zonal distribution that mainly focused on the main visual area at the center, the road just ahead, and the right side of the main visual area while approaching the special light zones. The results also showed that the variation in illumination and landscape in light zones was more important than driving experience to yield changes in visual cognition and driving behavior. It can be concluded that the special light zones can help relieve drivers' vision fatigue to some extent and further develop certain visual stimulus that can enhance drivers' attention. The study would provide a scientific basis for safety measurement implementation in extra-long tunnels.

  11. Capture-zone design in an aquifer influenced by cyclic fluctuations in hydraulic gradients

    Science.gov (United States)

    Zawadzki, Willy; Chorley, Don; Patrick, Guy

    2002-10-01

    Design of a groundwater pumping and treatment system for a wood-treatment facility adjacent to the tidally influenced Fraser River estuary required the development of methodologies to account for cyclic variations in hydraulic gradients. Design of such systems must consider the effects of these cyclic fluctuations on the capture of dissolved-phase contaminants. When the period of the cyclic fluctuation is much less than the travel time of the dissolved contaminant from the source to the discharge point, the hydraulic-gradient variations resulting from these cycles can be ignored. Capture zones are then designed based on the average hydraulic gradient determined using filter techniques on continuous groundwater-level measurements. When the period of cyclic fluctuation in hydraulic gradient is near to or greater than the contaminant travel time, the resulting hydraulic-gradient variations cannot be ignored. In these instances, procedures are developed to account for these fluctuations in the capture-zone design. These include proper characterization of the groundwater regime, assessment of the average travel time and period of the cyclic fluctuations, and numerical techniques which allow accounting for the cyclic fluctuations in the design of the capture zone. Résumé. L'étude d'un système de pompage et de traitement de l'eau souterraine d'une usine de traitement du bois proche de l'estuaire de la rivière Fraser, influencé par les marées, a nécessité la mise au point de méthodologies pour prendre en compte les variations cycliques de gradients hydrauliques. L'étude de tels systèmes doit considérer les effets de ces variations cycliques sur l'extraction des contaminants en phase dissoute. Lorsque la période des variations cycliques est très inférieure au temps de parcours du contaminant dissous entre la source et le point d'émergence, les variations du gradient hydraulique résultant de ces cycles peuvent être ignorées. Les zones d'extraction sont

  12. A theoretical study of factors influencing calcium-secretion coupling in a presynaptic active zone model.

    Science.gov (United States)

    Gil, Amparo; González-Vélez, Virginia; Segura, Javier; Gutiérrez, Luis Miguel

    2014-10-01

    A theoretical analysis of some of the relevant factors influencing the calcium time course and the strength and timing of release probabilities of vesicles evoked by an action potential in a calyx-type active zone is presented in this paper. In particular, our study focus on the comparison of cooperative vs non-cooperative calcium binding by the release site and the effect of the number of Ca(2+) binding sites on the calcium sensitivity for release. Regarding the comparison of cooperative and non-cooperative kinetic schemes, our simulations show that quite different results are obtained when considering one or another: a reduction in the release probability of more than a 50% is obtained when considering the cooperative kinetic scheme. Also, a delay in the average time for release appears when using this model for the calcium sensor. Our study also shows that a non-cooperative kinetic binding scheme gives rise to a well defined average calcium level for release assuming that the same kinetic constants are considered for all the sites. Our results also suggest that the central value of the calcium sensitivity for release depends on the number of binding sites N and the dissociation constant KD with a scaling law depending on NKD.

  13. Influence of orientation, glazing proportion and zone aspect ratio on the thermal performance of buildings during the winter period.

    Science.gov (United States)

    Zenginis, Dimitrios G; Kontoleon, Karolos J

    2017-07-25

    The objective of this study is to assess the effect of orientation, glazing proportion and aspect ratio of building zones on heat fluxes through their surfaces, under specific environmental conditions. The investigation is carried out for thermally-insulated building zones with a varying facade orientation corresponding to each cardinal point, during the winter period in the northern Greek region. For this purpose, three glazing-to-facade ratios (GR) are taken into account; along with the glazing ratio the influence of the glazing U value is also considered. Regarding the impact of the fenestration layout geometry, five different building aspect ratio profiles are examined. Thermal fluxes are assessed for two different indoor temperature settings, while the operation of the heating unit is assumed to be continuous. The transient thermal analysis with its mathematical formulation and solution are based on the thermal-network modelling approach, while the solar heat gain through glazing relies on the sunlit-pattern approach; in this way, the stricken by the solar rays glazing area is projected onto any interior surfaces to form the so called "sunlit" areas. As the orientation, glazing proportion and aspect ratio of the building zone vary, so do the sizes and shapes of the illuminated "sunlit" areas. Accordingly, the delivered into the zone direct solar energy and its diffused and ground reflected components can be determined. The adopted methodology provides a more accurate determination of solar heat gain with respect to glazing proportion and orientation as well as zone aspect ratio. With regard to surface orientation, glazing proportion and aspect ratio, computer results demonstrate the improvement of the thermal performance for a building zone with a south oriented glazing surface, as well as the deterioration for the other surface orientations; relative increases/decreases in the energy fluxes of a rectangular shaped building zone compared to a square

  14. Subtidal benthic marine algae of the Marine State Park of Laje de Santos (São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Gilberto M. Amado Filho

    2006-12-01

    Full Text Available Laje de Santos Marine State Park has been pointed out as a site of high marine diversity. In spite of its importance to conservation of marine biota no results of investigations about its marine biodiversity have been published. The aim of this work was to characterize the subtidal seaweed flora of this Marine Park. Samplings were performed by scuba diving: a qualitative one that included the subtidal zone down to 26 m depth and other quantitative at two pre-determined depths, 10 and 20 m. Among the 129 taxa identified, 5 species were identified for the first time for the São Paulo State, 3 for the Brazilian coast and 1 for the South Atlantic Ocean. The most abundant algae were Sargassum vulgare and turf composed by geniculate coralline and filamentous groups. The frequency of occurrence of taxa revealed that most of species are restricted to frequencies less than 20 % in all samples. The analyses of the subtidal marine benthic algal flora indicate the Marine State Park of Laje de Santos as a site of elevated species richness and that its floristic composition is related to a benthic community structure dominated by turf-forming groups and population of S. vulgare.O Parque Estadual Marinho da Laje de Santos tem sido apontado como local de elevada diversidade marinha. Apesar de sua importância para a conservação da biota marinha não existem resultados efetivamente publicados. O objetivo deste trabalho é o de caracterizar a flora marinha bentônica desse Parque Marinho. Amostragens foram realizadas por mergulho autônomo: uma qualitativa que incluiu a zona do sublitoral até a profundidade de 26 m e outra quantitativa em duas profundidades pré-determinadas, 10 e 20 m.. Dentre os 129 táxons encontrados, foram identificadas pela primeira vez, 5 espécies para o Estado de São Paulo, 3 espécies para o litoral brasileiro e 1 espécie para o Atlântico sul. As algas mais abundantes foram Sargasum vulgare e tufos compostos de coralin

  15. Influence of the Surf Zone on the Marine Aerosol Concentration in a Coastal Area

    NARCIS (Netherlands)

    Tedeschi, G.; Eijk, A.M.J. van; Piazzolla, J.; Kusmierczyk-Michulec, J.T.

    2017-01-01

    Sea-salt aerosol concentrations in the coastal zone are assessed with the numerical aerosol-transport model MACMod that applies separate aerosol source functions for open ocean and the surf zone near the sea–land transition. Numerical simulations of the aerosol concentration as a function of

  16. The Influence of Train Running Direction and Track Supports Position on the Behaviour of Transition Zones

    NARCIS (Netherlands)

    Sanudo, R(extern); Miranda, M.; Markine, V.L.; Dell'olio, L.

    2016-01-01

    Different types of track infrastructure can be found along railway lines. Separation zones between these different types of structures are the source of a lot of problems. Transition zones on a railway line represent a gradual solution for the problems between conventional railway structure and

  17. Modeling the influence of tectonic extrusion and volume loss on the geometry, displacement, vorticity, and strain compatibility of ductile shear zones

    Science.gov (United States)

    Baird, Graham B.; Hudleston, Peter J.

    2007-10-01

    Oblate strains are often observed in meso-scale ductile shear zones and this is generally taken to indicate narrowing across the shear zone during formation. Volume loss is one mechanism that could produce shear zone narrowing. However, not all shear zones display characteristics consistent with volume loss, and in such cases, the narrowing must be accomplished by the extrusion of material from within the shear zone. To explore the relationship between shear zone geometry, volume loss, and extrusion, shear zones were mathematically modeled. Results demonstrate the important influence of pure shear and volume loss on controlling the geometry, displacement, and vorticity of ductile shear zones. Further, volume loss does not preclude extrusion unless, for a given volume loss, the strain is of a specific geometry. Extrusion is a likely mechanism important in shear zone development, even if volume loss occurs. Extrusion presents strain compatibility problems because, unlike crustal-scale shear zones, meso-scale ductile shear zones do not possess a free surface. If extrusion occurs, bulk strain compatibility can be maintained if shear zones interlink in anastomosing arrays or change in thickness, though not all shear zone systems display such characteristics. Modeling results elucidate the deformation style of shear zone in the northwest Adirondacks in NY and in the Kebnekaise region in northern Sweden.

  18. Influence of grassing targeted into the recharge zone on the nitrate concentrations and nitrogen leaching out of the drained catchment.

    Science.gov (United States)

    Zajíček, Antonín; Fučík, Petr; Kvítek, Tomáš

    2015-04-01

    completely, the decrease of the monthly average nitrogen load was even by 47% from 4.75 kg N/month/ha before grassing to 2.52 kg N/month/ha after grassing the recharge area. The results showed that nitrate concentration in drainage water were much more influenced by the land use of the recharge zones within the drainage subcatchment than by land use in the drained area itself. The experiment proves that grassing focused on the proper catchment area (recharge zone) can be a useful tool for reducing nitrates in drainage water. While permanent grassland placed directly in the drained area (catchment discharge zone) did not show any effect, the grassing focused on the catchment recharge area demonstrated a significant decrease in both, NO3 concentrations and N loads. This findings are of crucial importance for improving the water quality of small streams as well as groundwater in agriculturally exploited areas, for planning protective zones within large catchments of potable water reservoirs, and also for protecting small local surface or groundwater sources of potable water.

  19. ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

    KAUST Repository

    Dasari, Hari Prasad

    2017-07-18

    The Red Sea convergence zone (RSCZ) is formed by opposite surface winds blowing from northwest to southeast directions at around 18°-19°N between October and January. A reverse-oriented, low-level monsoon trough at 850hPa, known as the Red Sea trough (RST), transfers moisture from the southern Red Sea to RSCZ. The positions of the RSCZ and RST and the intensity of the RST have been identified as important factors in modulating weather and climatic conditions across the Middle East. Here, we investigate the influence of the El Niño southern oscillation (ENSO) on the interannual variability of RSCZ, RST, and regional rainfall during winter months. Our results indicate that El Niño (warm ENSO phase) favours a shift of the RSCZ to the north and a strengthening of the RST in the same direction. Conversely, during November and December of La Niña periods (cold ENSO phase), the RSCZ shift to the south and the RST strengthens in the same direction. During El Niño periods, southeasterly wind speeds increase (20-30%) over the southern Red Sea and northwesterly wind speeds decrease (10-15%) over the northern Red Sea. Noticeable increases in the number of rainy days and the intensity of rain events are observed during El Niño phases. These increases are associated with colder than normal air intrusion at lower levels from the north combined with warm air intrusion from the south over the RSCZ. Our analysis suggests that during El Niño winters, warmer sea surface temperatures and higher convective instability over the Red Sea favour local storms conditions and increase rainfall over the Red Sea and adjoining regions.

  20. Biofilter design for effective nitrogen removal from stormwater - influence of plant species, inflow hydrology and use of a saturated zone.

    Science.gov (United States)

    Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Fletcher, Tim D; Hatt, Belinda E; Deletic, Ana

    2014-01-01

    The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configuration was conducted across a 1.5-year period to further investigate the mechanisms and influences driving biofilter nitrogen processing. This paper presents outflow concentrations of total nitrogen from two sampling events across both 'wet' and 'dry' frequency dosing, and from sampling across two points in the outflow hydrograph. All plant species were effective under conditions of frequent dosing, but extended drying increased variation between species and highlighted the importance of a saturated zone in maintaining biofilter function. The saturated zone also effectively treated the volume of stormwater stored between inflow events, but this extended detention provided no additional benefit alongside the rapid processing of the highest performing species. Hence, the saturated zone reduced performance differences between plant species, and potentially acts as an 'insurance policy' against poor sub-optimal plant selection. The study shows the importance of biodiversity and inclusion of a saturated zone in protecting against climate variability.

  1. Influence of the Surf Zone on the Marine Aerosol Concentration in a Coastal Area

    Science.gov (United States)

    Tedeschi, Gilles; van Eijk, Alexander M. J.; Piazzola, Jacques; Kusmierczyk-Michulec, Jolanta T.

    2017-01-01

    Sea-salt aerosol concentrations in the coastal zone are assessed with the numerical aerosol-transport model MACMod that applies separate aerosol source functions for open ocean and the surf zone near the sea-land transition. Numerical simulations of the aerosol concentration as a function of offshore distance from the surf zone compare favourably with experimental data obtained during a surf-zone aerosol experiment in Duck, North Carolina in autumn 2007. Based on numerical simulations, the effect of variations in aerosol production (source strength) and transport conditions (wind speed, air-sea temperature difference), we show that the surf-zone aerosols are replaced by aerosols generated over the open ocean as the airmass advects out to sea. The contribution from the surf-generated aerosol is significant during high wind speeds and high wave events, and is significant up to 30 km away from the production zone. At low wind speeds, the oceanic component dominates, except within 1-5 km of the surf zone. Similar results are obtained for onshore flow, where no further sea-salt aerosol production occurs as the airmass advects out over land. The oceanic aerosols that are well-mixed throughout the boundary layer are then more efficiently transported inland than are the surf-generated aerosols, which are confined to the first few tens of metres above the surface, and are therefore also more susceptible to the type of surface (trees or grass) that determines the deposition velocity.

  2. Tidal and subtidal exchange flows at an inlet of the Wadden Sea

    Science.gov (United States)

    Valle-Levinson, Arnoldo; Stanev, Emil; Badewien, Thomas H.

    2018-03-01

    Observations of underway velocity profiles during complete spring and neap tidal cycles were used to determine whether the spatial structures of tidal and subtidal flows at a tidal inlet in a multiple-inlet embayment are consistent with those observed at single-inlet embayments. Measurements were obtained at the Otzumer Balje, one of the multiple inlets among the East Frisian Islands of the Wadden Sea. The 1.5 km-wide inlet displayed a bathymetric profile consisting of a channel ∼15 m deep flanked by frictional effects from bathymetry molded tidal flows. Spatial distributions of semidiurnal tidal current amplitude and phase conform to those predicted by an analytical model for a basin with one inlet. Maximum semidiurnal flows appear at the surface in the channel, furthest away from bottom friction effects. Therefore, Otzumer Balje displays tidal hydrodynamics that are independent of the other inlets of the embayment. Subtidal exchange flows are laterally sheared, with residual inflow in the channel combined with outflow over shoals. The spatial distribution of these residual flows follow theoretical expectations of tidally driven flows interacting with bathymetry. Such distribution is similar to the tidal residual circulation at other inlets with only one communication to the ocean, suggesting that at subtidal scales the Otzumer Balje responds to tidal forcing independently of the other inlets.

  3. Influence of the welding parameters on the heat affected zone for aluminium welding

    Directory of Open Access Journals (Sweden)

    Meseguer-Valdenebro José L.

    2016-01-01

    Full Text Available This work analyzes the Heat Affected Zone in an aluminum alloy welded assembly using the Metal Inert Gas welding technique. Making use of numerical simulations of the involved thermal processes, the aluminum alloy cooling curve is calculated and the extension of the Heat Affected Zone is evaluated. The connection between this last parameter, the cooling rate, and the maximum obtained temperature is assessed. Additionally, the response surface method is exploited to fit the dependence of the Heat Affected Zone with the welding parameters and to optimize these parameters in order to minimize that region.

  4. [The role of ecovirological zoning in prediction of the influence of climatic changes on arbovirus habitats].

    Science.gov (United States)

    Shchelkanov, M Iu; Gromashevskiĭ, V L; L'vov, D K

    2006-01-01

    The paper contains methodical basis of ecovirological zoning in the analysis of the problem of interrelation between climatic changes and the activity of natural nidi of arboviral infection. The authors offer an original hieroglyphic system of cartographic signs of arboviruses and a map of prevalence of arboviruses in various landscape zones of Noth Eurasia (within the boundaries of the former USSR.) They analyze the three main cartographic approaches to ecovirological zoning of natural territorial complexes, which imply analysis of a ralation to a landscape, conjugated component analysis, and paleographic reconstruction analysis.

  5. Influence of the Summer Marine Layer on Maritime Chaparral and Implications for Conservation Policy in the California Coastal Zone

    OpenAIRE

    Vasey, Michael Charles

    2012-01-01

    Influence of the Summer Marine Layer on Maritime Chaparral and Implications for Conservation Policy in the California Coastal ZoneMichael C. VaseyThe California coast is renowned for its exceptional diversity of local endemic species, particularly in evergreen, sclerophyllous shrubland known as maritime chaparral. This species rich, fire-adapted shrubland is typical of other regions in the world with Mediterranean-type climates characterized by cool, wet winters and long, dry summers. Th...

  6. [Fish community structure and its seasonal change in subtidal sandy beach habitat off southern Gouqi Island].

    Science.gov (United States)

    Wang, Zhen-Hua; Wang, Kai; Zhao, Jing; Zhang, Shou-Yu

    2011-05-01

    To understand the characteristics of fish community structure in sandy beach habitats of island reef water areas, and to evaluate the potential capacity of these habitats in local fish stock maintenance, fishes were monthly collected with multi-mesh trammel nets in 2009 from the subtidal sandy beach habitat off southern Gouqi Island, taking the adjacent rocky reef habitat as the control. alpha and beta species diversity indices, index of relative importance (IRI), relative catch rate, and dominance curve for abundance and biomass (ABC curve) were adopted to compare the fish species composition, diversity, and community pattern between the two habitats, and multivariate statistical analyses such as non-metric multidimensional scaling (nMDS) and cluster were conducted to discuss the fish assemblage patterns. A total of 63 fish species belonging to 11 orders, 38 families, and 56 genera were collected, of which, 46 fish species were appeared in the two habitats. Due to the appearance of more warm water species in sandy bottom, the fishes in subtidal sandy beach habitat showed much higher richness, and the abundance catch rate (ACR) from May to July was higher than that in rocky reef habitat. In most rest months, the ACR in subtidal sandy beach habitat also showed the similar trend. However, the species richness and diversity in spring and summer were significantly lower in subtidal sandy beach habitat than in rocky reef habitat, because of the high species dominance and low evenness in the sandy beach habitat. Japanese tonguefish (Paraplagusia japonica) was the indicator species in the sandy beach habitat, and dominated in early spring, later summer, autumn, and winter when the fishing pressure was not strong. In sandy bottom, a unique community structure was formed and kept in dynamic, due to the nursery use of sandy beach by Japanese anchovy (Engraulis japonicus) from May to July, the gathering of gray mullet (Mugil cephalus) in most months for feeding, and the large

  7. Effects of patch size and position above the substratum during early succession of subtidal soft-bottom communities

    Science.gov (United States)

    Pacheco, Aldo S.; Thiel, Martin; Oliva, Marcelo E.; Riascos, José M.

    2012-12-01

    Early macrobenthos succession in small, disturbed patches on subtidal soft bottoms is facilitated by the arrival of post-larval colonizers, in particular by active and passive dispersers along the seafloor or through the water column. Using a field experiment at two contrasting sites (protected vs. exposed to wave action), we evaluated the role of (a) active and passive dispersal through the water column and (b) the influence of small-scale spatial variability during succession of subtidal macrobenthic communities in northern Chile. Containers of two sizes (surface area: small—0.12 m2 and large—0.28 m2) at two positions above the natural substratum (height: low—3 cm and high—26 cm) were filled with defaunated sediment, installed at two sandy sublittoral sites (7-9 m water depth) and sampled after 7, 15, 30, 60 and 90 days, together with the natural bottom sediment. The experiment took place during austral fall (from late March to early July 2010), when both larval and post-larval stages are abundant. At the exposed site, early succession was driven by similar proportions of active and passive dispersers. A sequence from early, late and reference communities was also evident, but container position and size affected the proportional abundance of dispersal types. At the protected site, the successional process started with abundant colonization of active dispersers, but toward the end of the experiment, the proportion of swimmer/crawlers increased, thus resembling the dispersal types found in the natural community. At this site, the position above the sediment affected the proportional abundance of dispersal types, but patch size had no effect. This study highlights that macrobenthic post-larvae can reach at least 26 cm high above the bottom (actively or passively, depending on site exposure), thus playing an important role during early succession of sublittoral soft bottoms. The active or passive use of the sediment-water interphase may also play an

  8. Physical disturbance and subtidal habitat structure on open rocky coasts: Effects of wave exposure, extent and intensity

    Science.gov (United States)

    Wernberg, Thomas; Connell, Sean D.

    2008-08-01

    suggest that the effect of disturbance depended on wave exposure within the range of exposures tested in this study (i.e. open coasts). We recognise that wave exposure can be fundamental to habitat structure of subtidal rocky coasts, but we suggest that its influence may be mediated by the biological setting (e.g., canopy composition).

  9. The influence of riverine nitrogen on the dynamics of the North Sea oxygen minimum zone

    Science.gov (United States)

    Große, Fabian; Kreus, Markus; Lenhart, Hermann; Pätsch, Johannes

    2016-04-01

    lowest bottom oxygen concentrations. In 2002, a year with high discharges from the European continental rivers, oxygen concentrations of less than 6 unit{mg L-1} are reached in that region, while in 2010 values stay well above 7.5 unit{mg L-1}. Mass balance calculations show that the remarkably lower values in 2002 are mainly caused by enhanced pelagic and benthic bacterial remineralisation during summer stratification (factor 1.55 higher than in 2010). The TBNT analysis reveals that almost 50 unit{%} of the bacterial consumption in that region are driven by the N supply from the Atlantic. However, the large continental rivers also account for about 23 unit{%} in 2010, and even 30 unit{%} in 2002. It further shows that in 2002, remineralisation due to N originating from these rivers is about twice as high as in 2010, representing the largest relative difference among all contributors. This demonstrates the great influence of the N input from the continental rivers on the oxygen dynamics in the North Sea minimum zone, and emphasises their importance for the eutrophication management in the southern central North Sea. {References} Troost, T. A., Blaas, M., Los, F. J. (2013). The role of atmospheric deposition in the eutrophication of the North Sea: a model analysis. Journal of Marine Systems, 125, 101-112.

  10. Widespread detection of human- and ruminant-origin Bacteroidales markers in subtidal waters of the Salish Sea in Washington State.

    Science.gov (United States)

    Oyafuso, Zack S; Baxter, Anne E; Hall, Jason E; Naman, Sean M; Greene, Correigh M; Rhodes, Linda D

    2015-09-01

    Rising populations around coastal systems are increasing the threats to marine water quality. To assess anthropogenic fecal influence, subtidal waters were examined monthly for human- and ruminant-sourced Bacteroidales markers at 80 sites across six oceanographic basins of the Salish Sea (Washington State) from April through October, 2011. In the basins containing cities with individual populations>190,000, >50% of sites were positive for the human marker, while in the basins with high densities of dairy and cattle operations, ∼30% of sites were positive for the ruminant marker. Marker prevalence was elevated in spring (April and May) and fall (October) and reduced during summer (June through September), corresponding with seasonal precipitation. By logistic regression, the odds of human marker detection increased with percentage of adjacent catchment impervious surface, dissolved nitrate concentration, and abundance of low nucleic acid bacteria, but decreased with salinity and chlorophyll fluorescence. The odds of ruminant marker detection increased with dissolved ammonium concentration, mean flow rate for the nearest river, and adjacent shoreline length. These relationships are consistent with terrestrial to marine water flow as a transport mechanism. Thus, Bacteroidales markers traditionally used for identifying nearby sources can be used for assessing anthropogenic fecal inputs to regional marine ecosystems.

  11. Framework Design and Influencing Factor Analysis of a Water Environmental Functional Zone-Based Effluent Trading System

    Science.gov (United States)

    Chen, Lei; Han, Zhaoxing; Li, Shuang; Shen, Zhenyao

    2016-10-01

    The efficacy of traditional effluent trading systems is questionable due to their neglect of seasonal hydrological variation and the creation of upstream hot spots within a watershed. Besides, few studies have been conducted to distinguish the impacts of each influencing factor on effluent trading systems outputs. In this study, a water environmental functional zone-based effluent trading systems framework was configured and a comprehensive analysis of its influencing factors was conducted. This proposed water environmental functional zone-based effluent trading systems was then applied for the control of chemical oxygen demand in the Beiyun River watershed, Beijing, China. Optimal trading results highlighted the integration of water quality constraints and different hydrological seasons, especially for downstream dischargers. The optimal trading of each discharger, in terms of pollutant reduction load and abatement cost, is greatly influenced by environmental and political factors such as background water quality, the location of river assessment points, and tradable discharge permits. In addition, the initial permit allowance has little influence on the market as a whole but does impact the individual discharger. These results provide information that is critical to understanding the impact of policy design on the functionality of an effluent trading systems.

  12. Framework Design and Influencing Factor Analysis of a Water Environmental Functional Zone-Based Effluent Trading System.

    Science.gov (United States)

    Chen, Lei; Han, Zhaoxing; Li, Shuang; Shen, Zhenyao

    2016-10-01

    The efficacy of traditional effluent trading systems is questionable due to their neglect of seasonal hydrological variation and the creation of upstream hot spots within a watershed. Besides, few studies have been conducted to distinguish the impacts of each influencing factor on effluent trading systems outputs. In this study, a water environmental functional zone-based effluent trading systems framework was configured and a comprehensive analysis of its influencing factors was conducted. This proposed water environmental functional zone-based effluent trading systems was then applied for the control of chemical oxygen demand in the Beiyun River watershed, Beijing, China. Optimal trading results highlighted the integration of water quality constraints and different hydrological seasons, especially for downstream dischargers. The optimal trading of each discharger, in terms of pollutant reduction load and abatement cost, is greatly influenced by environmental and political factors such as background water quality, the location of river assessment points, and tradable discharge permits. In addition, the initial permit allowance has little influence on the market as a whole but does impact the individual discharger. These results provide information that is critical to understanding the impact of policy design on the functionality of an effluent trading systems.

  13. INFLUENCE OF WEATHER CONDITIONS ON RED BEET YIELD IN VARIOUS ZONES OF THE FORE-CAUCASUS

    Directory of Open Access Journals (Sweden)

    M. S. Gaplaev

    2014-01-01

    Full Text Available Based on the researches conducted in conditions of vertical zonality of the Chechen Republic, the high-yielding varieties of red beet in the certain climate and environmental conditions were selected. Moving from the plain zone to the piedmont and the mountain zones, the yield of red beet roots has increased by 1,6-3,4 t/ha regardless of early ripeness of cultivars and hybrids. Application of mathematical modeling allows the selection of the varieties, which are able to realize their yield potential in various conditions.

  14. Petroleum hydrocarbon-induced injury to subtidal marine sediment resources. Subtidal study number 1a. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    Energy Technology Data Exchange (ETDEWEB)

    O`Clair, C.E.; Short, J.W.; Rice, S.D.

    1996-04-01

    To determine the distribution of oil in subtidal sediments after the Exxon Valdez oil spill we sampled sediments at six depths (0, 3, 6, 20, 40 and 100 m) at 53 locations in Prince William Sound and the northern Gulf of Alaska from 1989 to 1991. Results are based on 1278 sediment samples analyzed by gas chromatography/mass spectrometry. In 1989, the oil concentration was greatest in the Sound at 0 m. Outside the Sound, Exxon Valdez oil occurred at Chugach Bay, Hallo Bay, Katmai Bay, and Windy Bay in 1989. Hydrocarbons often matched Exxon Valdez oil less closely, oil was more patchily distributed, and the oil concentration decreased in sediments after 1989.

  15. A herbivore knows its patch: luderick, Girella tricuspidata, exhibit strong site fidelity on shallow subtidal reefs in a temperate marine park.

    Directory of Open Access Journals (Sweden)

    Adrian M Ferguson

    Full Text Available Understanding movement patterns, habitat use and behaviour of fish is critical to determining how targeted species may respond to protection provided by "no-take" sanctuary zones within marine parks. We assessed the fine and broad scale movement patterns of an exploited herbivore, luderick (Girella tricuspidata, using acoustic telemetry to evaluate how this species may respond to protection within Jervis Bay (New South Wales, Australia. We surgically implanted fourteen fish with acoustic transmitters and actively and passively tracked individuals to determine fine and broad scale movement patterns respectively. Eight fish were actively tracked for 24 h d¯(1 for 6 d (May 2011, and then intermittently over the following 30 d. Six fish were passively tracked from December 2011 to March 2012, using a fixed array of receivers deployed across rocky reefs around the perimeter of the bay. Luderick exhibited strong site fidelity on shallow subtidal reefs, tending to remain on or return consistently to the reef where they were caught and released. All eight fish actively tracked used core areas solely on their release reef, with the exception of one fish that used multiple core areas, and four of the six fish passively tracked spent between 75 to 96% of days on release reefs over the entire tracking period. Luderick did move frequently to adjacent reefs, and occasionally to more distant reefs, however consistently returned to their release reef. Luderick also exhibited predictable patterns in movement between spatially distinct daytime and night-time core use areas. Night-time core use areas were generally located in sheltered areas behind the edge of reefs. Overall, our data indicate luderick exhibit strong site fidelity on shallow subtidal reefs in Jervis Bay and suggests that this important herbivore may be likely to show a positive response to protection within the marine park.

  16. Carbon flow pattern in the forest zones of Nigeria as influenced by ...

    African Journals Online (AJOL)

    use

    carbon flow pattern in the forest zones and invariably causes carbon emission had not changed. Though a look at the fractional contribution of each of these activities in 2000 as against that of 1990 estimates shows a marked change. The study also concludes that if there is no change in the estimated deforestation rate of ...

  17. Influence of environment and mitochondrial heritage on the ecological characteristics of fish in a hybrid zone.

    Directory of Open Access Journals (Sweden)

    Nicolas Stolzenberg

    Full Text Available BACKGROUND: Ecological characteristics (growth, morphology, reproduction arise from the interaction between environmental factors and genetics. Genetic analysis of individuals' life history traits might be used to improve our understanding of mechanisms that form and maintain a hybrid zone. METHODOLOGY/PRINCIPAL FINDINGS: A fish hybrid zone was used to characterize the process of natural selection. Data were collected during two reproductive periods (2001 and 2002 and 1117 individuals (nase, Chondrostama nasus nasus, sofie C. toxostoma toxostoma and hybrids were sampled. Reproductive dates of the two parental species overlapped at sympatric sites. The nase had an earlier reproductive period than the sofie; males had longer reproductive periods for both species. Hybridisation between female nase and male sofie was the most likely. Hybrids had a reproductive period similar to the inherited parental mitochondrial type. Growth and reproductive information from different environments has been synthesised following a bayesian approach of the von Bertalanffy model. Hybrid life history traits appear to link with maternal heritage. Hybrid size from the age of two and size at first maturity appeared to be closer to the size of the maternal origin species (nase or sofie. Median growth rates for hybrids were similar and intermediate between those of the parental species. We observed variable life history traits for hybrids and pure forms in the different parts of the hybrid zone. Geometrical analysis of the hybrid fish shape gave evidence of two main morphologies with a link to maternal heritage. CONCLUSIONS/SIGNIFICANCE: Selective mating seemed to be the underlying process which, with mitochondrial heritage, could explain the evolution of the studied hybrid zone. More generally, we showed the importance of studies on hybrid zones and specifically the study of individuals' ecological characteristics, to improve our understanding of speciation.

  18. Influence of Environment and Mitochondrial Heritage on the Ecological Characteristics of Fish in a Hybrid Zone

    Science.gov (United States)

    Stolzenberg, Nicolas; Nguyen The, Bénédicte; Salducci, Marie Dominique; Cavalli, Laurent

    2009-01-01

    Background Ecological characteristics (growth, morphology, reproduction) arise from the interaction between environmental factors and genetics. Genetic analysis of individuals' life history traits might be used to improve our understanding of mechanisms that form and maintain a hybrid zone. Methodology/Principal Findings A fish hybrid zone was used to characterize the process of natural selection. Data were collected during two reproductive periods (2001 and 2002) and 1117 individuals (nase, Chondrostama nasus nasus, sofie C. toxostoma toxostoma and hybrids) were sampled. Reproductive dates of the two parental species overlapped at sympatric sites. The nase had an earlier reproductive period than the sofie; males had longer reproductive periods for both species. Hybridisation between female nase and male sofie was the most likely. Hybrids had a reproductive period similar to the inherited parental mitochondrial type. Growth and reproductive information from different environments has been synthesised following a bayesian approach of the von Bertalanffy model. Hybrid life history traits appear to link with maternal heritage. Hybrid size from the age of two and size at first maturity appeared to be closer to the size of the maternal origin species (nase or sofie). Median growth rates for hybrids were similar and intermediate between those of the parental species. We observed variable life history traits for hybrids and pure forms in the different parts of the hybrid zone. Geometrical analysis of the hybrid fish shape gave evidence of two main morphologies with a link to maternal heritage. Conclusions/Significance Selective mating seemed to be the underlying process which, with mitochondrial heritage, could explain the evolution of the studied hybrid zone. More generally, we showed the importance of studies on hybrid zones and specifically the study of individuals' ecological characteristics, to improve our understanding of speciation. PMID:19536286

  19. Influence of environment and mitochondrial heritage on the ecological characteristics of fish in a hybrid zone.

    Science.gov (United States)

    Stolzenberg, Nicolas; Nguyen The, Bénédicte; Salducci, Marie Dominique; Cavalli, Laurent

    2009-06-18

    Ecological characteristics (growth, morphology, reproduction) arise from the interaction between environmental factors and genetics. Genetic analysis of individuals' life history traits might be used to improve our understanding of mechanisms that form and maintain a hybrid zone. A fish hybrid zone was used to characterize the process of natural selection. Data were collected during two reproductive periods (2001 and 2002) and 1117 individuals (nase, Chondrostama nasus nasus, sofie C. toxostoma toxostoma and hybrids) were sampled. Reproductive dates of the two parental species overlapped at sympatric sites. The nase had an earlier reproductive period than the sofie; males had longer reproductive periods for both species. Hybridisation between female nase and male sofie was the most likely. Hybrids had a reproductive period similar to the inherited parental mitochondrial type. Growth and reproductive information from different environments has been synthesised following a bayesian approach of the von Bertalanffy model. Hybrid life history traits appear to link with maternal heritage. Hybrid size from the age of two and size at first maturity appeared to be closer to the size of the maternal origin species (nase or sofie). Median growth rates for hybrids were similar and intermediate between those of the parental species. We observed variable life history traits for hybrids and pure forms in the different parts of the hybrid zone. Geometrical analysis of the hybrid fish shape gave evidence of two main morphologies with a link to maternal heritage. Selective mating seemed to be the underlying process which, with mitochondrial heritage, could explain the evolution of the studied hybrid zone. More generally, we showed the importance of studies on hybrid zones and specifically the study of individuals' ecological characteristics, to improve our understanding of speciation.

  20. Lithological influences on contemporary and long-term regolith weathering at the Luquillo Critical Zone Observatory

    Science.gov (United States)

    Buss, Heather L.; Lara, Maria Chapela; Moore, Oliver; Kurtz, Andrew C.; Schulz, Marjorie S.; White, Arthur F.

    2017-01-01

    Lithologic differences give rise to the differential weatherability of the Earth’s surface and globally variable silicate weathering fluxes, which provide an important negative feedback on climate over geologic timescales. To isolate the influence of lithology on weathering rates and mechanisms, we compare two nearby catchments in the Luquillo Critical Zone Observatory in Puerto Rico, which have similar climate history, relief and vegetation, but differ in bedrock lithology. Regolith and pore water samples with depth were collected from two ridgetops and at three sites along a slope transect in the volcaniclastic Bisley catchment and compared to existing data from the granitic Río Icacos catchment. The depth variations of solid-state and pore water chemistry and quantitative mineralogy were used to calculate mass transfer (tau) and weathering solute profiles, which in turn were used to determine weathering mechanisms and to estimate weathering rates.Regolith formed on both lithologies is highly leached of most labile elements, although Mg and K are less depleted in the granitic than in the volcaniclastic profiles, reflecting residual biotite in the granitic regolith not present in the volcaniclastics. Profiles of both lithologies that terminate at bedrock corestones are less weathered at depth, near the rock-regolith interfaces. Mg fluxes in the volcaniclastics derive primarily from dissolution of chlorite near the rock-regolith interface and from dissolution of illite and secondary phases in the upper regolith, whereas in the granitic profile, Mg and K fluxes derive from biotite dissolution. Long-term mineral dissolution rates and weathering fluxes were determined by integrating mass losses over the thickness of solid-state weathering fronts, and are therefore averages over the timescale of regolith development. Resulting long-term dissolution rates for minerals in the volcaniclastic regolith include chlorite: 8.9 × 10−14 mol m−2 s−1, illite: 2.1

  1. From forests to cattail: how does the riparian zone influence stream fish?

    Directory of Open Access Journals (Sweden)

    Lilian Casatti

    Full Text Available The aim of this study was to verify whether taxonomic and functional composition of stream fishes vary under three different preservation conditions of riparian zone: preserved (PRE, intermediate condition (INT, and degraded (DEG. Five stream stretches representing each condition were selected. Samples were taken from each stream in three occasions during the dry seasons from 2004 to 2007. Electro fishing (PRE and INT, sieves, dip nets, and hand seines (DEG were used according to the characteristics of each sampled site. Overall, 46 species were registered. Differences in the taxonomic and functional species composition among groups were found, following the condition of riparian zones. The ichthyofauna recorded in the PRE was typical to pristine environments, consisting of species with specialized habits, notably benthic insectivores, intolerant, and rheophilics. In the INT group, replacement of riparian forest with shrubs and/or grasses created environmental conditions which favor the occurrence of tolerant species but also harbor a residual fauna of sensitive species. DEG streams presented mostly detritivores, tolerant, small sized fishes which occupy the surface and preferred slow water flux. Changes in the species composition were represented by the occurrence and dominance of tolerant species in detriment of the more sensitive and specialist species, following the gradient of degradation in the riparian zone. Forested streams act as unique habitats to many specialized species and it can be presumable that the degradation of riparian vegetation can generate biotic homogenization which may reduce species diversity and ecosystem services.

  2. The macrofaunal communities in the shallow subtidal areas for the first 3 years after the Hebei Spirit oil spill.

    Science.gov (United States)

    Seo, Jin-Young; Kim, Moonkoo; Lim, Hyun-Sig; Choi, Jin-Woo

    2014-05-15

    In order to detect the early impact of the Hebei Spirit oil spill on the shallow subtidal macrozoobenthic communities, macrobenthic fauna were collected seasonally for 3 years. The alkylated PAHs concentrations within sediments near Mallipo beach remained as high as 129 ng g(-)(1) DW one month after the oil spill, but the concentration decreased below the background level thereafter. The number of species and density decreased in 4 months compared to those before the oil spill. An opportunistic polychaete, Prionospio paradisea, occurred as a dominant species at subtidal area near Mallipo beach in 10 months after the oil spill. Any mass mortality of amphipods and any clear dominance of opportunistic species were not detected except for the stations near Mallipo and Hagampo beaches. The macrobenthic communities at the shallow subtidal stations seemed to have a relatively stable faunal composition, even not fully recovered, in 3 years after the Hebei Spirit oil spill. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Improving a prediction system for oil spills in the Yellow Sea: effect of tides on subtidal flow.

    Science.gov (United States)

    Kim, Chang-Sin; Cho, Yang-Ki; Choi, Byoung-Ju; Jung, Kyung Tae; You, Sung Hyup

    2013-03-15

    A multi-nested prediction system for the Yellow Sea using drifter trajectory simulations was developed to predict the movements of an oil spill after the MV Hebei Spirit accident. The speeds of the oil spill trajectories predicted by the model without tidal forcing were substantially faster than the observations; however, predictions taking into account the tides, including both tidal cycle and subtidal periods, were satisfactorily improved. Subtidal flow in the simulation without tides was stronger than in that with tides because of reduced frictional effects. Friction induced by tidal stress decelerated the southward subtidal flows driven by northwesterly winter winds along the Korean coast of the Yellow Sea. These results strongly suggest that in order to produce accurate predictions of oil spill trajectories, simulations must include tidal effects, such as variations within a tidal cycle and advections over longer time scales in tide-dominated areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Network dynamics of the brain and influence of the epileptic seizure onset zone

    Science.gov (United States)

    Burns, Samuel P.; Santaniello, Sabato; Yaffe, Robert B.; Jouny, Christophe C.; Crone, Nathan E.; Bergey, Gregory K.; Anderson, William S.; Sarma, Sridevi V.

    2014-01-01

    The human brain is a dynamic networked system. Patients with partial epileptic seizures have focal regions that periodically diverge from normal brain network dynamics during seizures. We studied the evolution of brain connectivity before, during, and after seizures with graph-theoretic techniques on continuous electrocorticographic (ECoG) recordings (5.4 ± 1.7 d per patient, mean ± SD) from 12 patients with temporal, occipital, or frontal lobe partial onset seizures. Each electrode was considered a node in a graph, and edges between pairs of nodes were weighted by their coherence within a frequency band. The leading eigenvector of the connectivity matrix, which captures network structure, was tracked over time and clustered to uncover a finite set of brain network states. Across patients, we found that (i) the network connectivity is structured and defines a finite set of brain states, (ii) seizures are characterized by a consistent sequence of states, (iii) a subset of nodes is isolated from the network at seizure onset and becomes more connected with the network toward seizure termination, and (iv) the isolated nodes may identify the seizure onset zone with high specificity and sensitivity. To localize a seizure, clinicians visually inspect seizures recorded from multiple intracranial electrode contacts, a time-consuming process that may not always result in definitive localization. We show that network metrics computed from all ECoG channels capture the dynamics of the seizure onset zone as it diverges from normal overall network structure. This suggests that a state space model can be used to help localize the seizure onset zone in ECoG recordings. PMID:25404339

  5. Network dynamics of the brain and influence of the epileptic seizure onset zone.

    Science.gov (United States)

    Burns, Samuel P; Santaniello, Sabato; Yaffe, Robert B; Jouny, Christophe C; Crone, Nathan E; Bergey, Gregory K; Anderson, William S; Sarma, Sridevi V

    2014-12-09

    The human brain is a dynamic networked system. Patients with partial epileptic seizures have focal regions that periodically diverge from normal brain network dynamics during seizures. We studied the evolution of brain connectivity before, during, and after seizures with graph-theoretic techniques on continuous electrocorticographic (ECoG) recordings (5.4 ± 1.7 d per patient, mean ± SD) from 12 patients with temporal, occipital, or frontal lobe partial onset seizures. Each electrode was considered a node in a graph, and edges between pairs of nodes were weighted by their coherence within a frequency band. The leading eigenvector of the connectivity matrix, which captures network structure, was tracked over time and clustered to uncover a finite set of brain network states. Across patients, we found that (i) the network connectivity is structured and defines a finite set of brain states, (ii) seizures are characterized by a consistent sequence of states, (iii) a subset of nodes is isolated from the network at seizure onset and becomes more connected with the network toward seizure termination, and (iv) the isolated nodes may identify the seizure onset zone with high specificity and sensitivity. To localize a seizure, clinicians visually inspect seizures recorded from multiple intracranial electrode contacts, a time-consuming process that may not always result in definitive localization. We show that network metrics computed from all ECoG channels capture the dynamics of the seizure onset zone as it diverges from normal overall network structure. This suggests that a state space model can be used to help localize the seizure onset zone in ECoG recordings.

  6. The Influence of Static and Rotating Magnetic Fields on Heat and Mass Transfer in Silicon Floating Zones

    Science.gov (United States)

    Croll, A.; Dold, P.; Kaiser, Th.; Szofran, F. R.; Benz, K. W.

    1999-01-01

    Heat and mass transfer in float-zone processing are strongly influenced by convective flows in the zone. They are caused by buoyancy convection, thermocapillary (Marangoni) convection, or artificial sources such as rotation and radio-frequency heating. Flows in conducting melts can be controlled by the use of magnetic fields, either by damping fluid motion with static fields or by generating a defined flow with rotating fields. The possibilities of using static and rotating magnetic fields in silicon floating-zone growth have been investigated by experiments in axial static fields up to 5 T and in transverse rotating magnetic fields up to 7.5 mT. Static fields of a few 100 mT already suppress most striations but are detrimental to the radial segregation by introducing a coring effect. A complete suppression of dopant striations caused by time-dependent thermocapillary convection and a reduction of the coring to insignificant values, combined with a shift of the axial segregation profile toward a more diffusion-limited case, is possible with static fields greater than or equal to 1 T. However, under certain conditions the use of high axial magnetic fields can lead to the appearance of a new type of pronounced dopant striations, caused by thermoelectromagnetic convection. The use of a transverse rotating magnetic field influences the microscopic segregation at quite low inductions, of the order of a few millitesla. The field shifts time- dependent flows and the resulting striation patterns from a broad range of low frequencies at high amplitudes to a few high frequencies at low amplitudes.

  7. An adaptive reentry guidance method considering the influence of blackout zone

    Science.gov (United States)

    Wu, Yu; Yao, Jianyao; Qu, Xiangju

    2018-01-01

    Reentry guidance has been researched as a popular topic because it is critical for a successful flight. In view that the existing guidance methods do not take into account the accumulated navigation error of Inertial Navigation System (INS) in the blackout zone, in this paper, an adaptive reentry guidance method is proposed to obtain the optimal reentry trajectory quickly with the target of minimum aerodynamic heating rate. The terminal error in position and attitude can be also reduced with the proposed method. In this method, the whole reentry guidance task is divided into two phases, i.e., the trajectory updating phase and the trajectory planning phase. In the first phase, the idea of model predictive control (MPC) is used, and the receding optimization procedure ensures the optimal trajectory in the next few seconds. In the trajectory planning phase, after the vehicle has flown out of the blackout zone, the optimal reentry trajectory is obtained by online planning to adapt to the navigation information. An effective swarm intelligence algorithm, i.e. pigeon inspired optimization (PIO) algorithm, is applied to obtain the optimal reentry trajectory in both of the two phases. Compared to the trajectory updating method, the proposed method can reduce the terminal error by about 30% considering both the position and attitude, especially, the terminal error of height has almost been eliminated. Besides, the PIO algorithm performs better than the particle swarm optimization (PSO) algorithm both in the trajectory updating phase and the trajectory planning phases.

  8. Prominence of ichnologically influenced macroporosity in the karst Biscayne aquifer: Stratiform "super-K" zones

    Science.gov (United States)

    Cunningham, K.J.; Sukop, M.C.; Huang, H.; Alvarez, P.F.; Curran, H.A.; Renken, R.A.; Dixon, J.F.

    2009-01-01

    solutions for pipe flow, LBMs offer a new means of obtaining accurate permeability values for such materials. We suggest that the stratiform ichnogenic groundwater flow zones have permeabilities even more extreme (???2-5 orders of magnitude higher) than the Jurassic "super-K" zones of the giant Ghawar oil field. The flow zones of the Pleistocene Biscayne aquifer provide examples of ichnogenic macroporosity for comparative analysis of origin and evolution in other carbonate aquifers, as well as petroleum reservoirs. ?? 2008 Geological Society of America.

  9. The influence of riparian-hyporheic zone on the hydrological responses in an intermittent stream

    Directory of Open Access Journals (Sweden)

    A. Butturini

    2002-01-01

    Full Text Available Stream and riparian groundwater hydrology has been studied in a small intermittent stream draining a forested catchment for a system representative of a Mediterranean climate. The relationship between precipitation and stream runoff and the interactions between stream water and the surrounding riparian groundwater have been analysed under a wide spectrum of meteorological conditions. The hypothesis that the hydrological condition of the near-stream groundwater compartment can regulate the runoff generation during precipitation events was tested. Stream runoff is characterised by a summer dry period, and precipitation input explained only 25% of runoff variability over the study period (r2 =0.25, d.f.=51, p2=0.80, d.f.=34, p Keywords: riparian zone, groundwater hydrology, runoff, intermittent stream, Mediterranean climate

  10. Experimental Evaluation of User Influence on Test Zone Size in Multi-probe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Ji, Yilin

    2017-01-01

    Over-the-air (OTA) radiated testing for multipleinput multiple-output (MIMO) capable mobile terminals has been actively discussed in the standardization in recent years, where multi-probe anechoic chamber (MPAC) method has been selected, together with the radiated two-stage (RTS) method. The supp......Over-the-air (OTA) radiated testing for multipleinput multiple-output (MIMO) capable mobile terminals has been actively discussed in the standardization in recent years, where multi-probe anechoic chamber (MPAC) method has been selected, together with the radiated two-stage (RTS) method...... available in the literature are typically limited to free space scenarios, where no user effect in the vicinity of MIMO terminal is present. There is a concern whether or not the test zone size should encompass the user phantom, together with the mobile terminal in the MPAC setup. To address this issue...

  11. Thanatology in protoplanetary discs. The combined influence of Ohmic, Hall, and ambipolar diffusion on dead zones

    Science.gov (United States)

    Lesur, Geoffroy; Kunz, Matthew W.; Fromang, Sébastien

    2014-06-01

    Protoplanetary discs are poorly ionised due to their low temperatures and high column densities and are therefore subject to three "non-ideal" magnetohydrodynamic (MHD) effects: Ohmic dissipation, ambipolar diffusion, and the Hall effect. The existence of magnetically driven turbulence in these discs has been a central question since the discovery of the magnetorotational instability (MRI). Early models considered Ohmic diffusion only and led to a scenario of layered accretion, in which a magnetically "dead" zone in the disc midplane is embedded within magnetically "active" surface layers at distances of about 1-10 au from the central protostellar object. Recent work has suggested that a combination of Ohmic dissipation and ambipolar diffusion can render both the midplane and surface layers of the disc inactive and that torques due to magnetically driven outflows are required to explain the observed accretion rates. We reassess this picture by performing three-dimensional numerical simulations that include all three non-ideal MHD effects for the first time. We find that the Hall effect can generically "revive" dead zones by producing a dominant azimuthal magnetic field and a large-scale Maxwell stress throughout the midplane, provided that the angular velocity and magnetic field satisfy Ω·B > 0. The attendant large magnetic pressure modifies the vertical density profile and substantially increases the disc scale height beyond its hydrostatic value. Outflows are produced but are not necessary to explain accretion rates ≲ 10-7 M⊙ yr-1. The flow in the disc midplane is essentially laminar, suggesting that dust sedimentation may be efficient. These results demonstrate that if the MRI is relevant for driving mass accretion in protoplanetary discs, one must include the Hall effect to obtain even qualitatively correct results. Appendices are available in electronic form at http://www.aanda.org

  12. Transformation and fate of microphytobenthos carbon in subtropical shallow subtidal sands: A 13C-labeling study

    NARCIS (Netherlands)

    Oakes, J.M.; Eyre, B.D.; Middelburg, J.J.

    2012-01-01

    Microphytobenthos (MPB) in photic sediments are highly productive but the fate of this production remains uncertain. Over 33 d, tracing of 13C from added bicarbonate in subtropical shallow subtidal sand showed rapid transfer of MPB-derived carbon to deeper sediment; below 2 cm (31% within 60 h)

  13. Hot and cold zones of the Southeast Indian Ridge and their influence on the peculiarities of its structure and magmatism (Numerical and Physical Modelling)

    Science.gov (United States)

    Dubinin, E. P.; Galushkin, Yu. I.; Grokholskii, A. L.; Kokhan, A. V.; Sushchevskaya, N. M.

    2017-05-01

    The paper describes the specific features of the bottom topography and morphostructural segmentation along the strike of the Southeast Indian Ridge (SEIR) and in the zones of influence of the Amsterdam-St. Paul hot spot and the anomalous zone of the relatively cold mantle in the area of the Australian-Antarctic discordance. Numerical estimates of changes of thermal state and strength of the crust in axial and off-axial zones of the SEIR were performed. Correlation between the thermal-rheological settings in the axial zone of the ridge with the seabed topography and the morphostructural segmentation and magmatism has been established. The numerical modelling results make it possible to assume the presence of along-axis asthenospheric flows under the axial zone of the SEIR. One of them, which was initiated by the Amsterdam-St. Paul point and the Kerguelen plume, is oriented from west to east, and the second, located east of the Australian-Antarctic discordance, is oriented from east to west. Taking into account the numerical modelling results of the thermal regime and the change in thickness of the brittle layer of the axial lithosphere, we performed a physical modelling of the influence of temperature anomalies in the mantle on the peculiarities of crustal deformation in the axial zones of the ridge. The experimental modelling showed that the presence of a thermal anomaly in the sublithosphere mantle in the form of a local heat source (hot spot) will noticeably influence the geometry of the rift axis and its position in relation to the hot spot. An area of anomalous topography forms under the influence of the hot spot, traces of which are preserved in the off-axis spreading flank zones, as in the case of the Amsterdam-St. Paul hot spot. More contrasting and dissected topography forms in zones with a relatively low typical mantle temperature in the process of crustal accretion.

  14. Factors Influencing Job Satisfaction and Anticipated Turnover among Nurses in Sidama Zone Public Health Facilities, South Ethiopia

    Science.gov (United States)

    Belachew, Tefera; Yimam, Ebrahim

    2014-01-01

    Background. Workplace turnover is destructive to nursing and patient outcomes as it leads to losing competent and qualified nurses. However, developments of coping strategies demand a clear understanding of workplace variables that either motivate nurses to remain employed or lead them to leave their current jobs. Objective. This study was designed toassess factors influencing job satisfaction and intention to turnover among nurses in Sidama zone public health facilities, in Southern Ethiopia. Method. Cross-sectional study design was carried out on 278 nurses using both qualitative and quantitative data collection methods from May 12 to June 05, 2010. Result. A total of 242 nurses were interviewed giving a response rate of 87%. Nearly two-third (68.6%) of the participants were female, and the mean age was 28 (±6.27) years for both sexes. All job satisfaction subscale except benefit and salary subscale were significant predictors of overall job satisfaction. Satisfactions with work environment and group cohesion (AOR: 0.25 [95% CI: 0.12, 0.51]), single cohesion (AOR: 2.56 [95% CI: 1.27, 5.13]), and working in hospital (AOR: 2.19 [95% CI: 1.12, 4.30]) were the final significant predictors of anticipated turnover of Sidama zone nurses. Conclusions. More than any factors managers should consider the modification of working environment and group cohesions rather than trying to modify nurses to retain and maintain more experienced nurses for the organizations. PMID:24707397

  15. Factors Influencing Job Satisfaction and Anticipated Turnover among Nurses in Sidama Zone Public Health Facilities, South Ethiopia

    Directory of Open Access Journals (Sweden)

    Agezegn Asegid

    2014-01-01

    Full Text Available Background. Workplace turnover is destructive to nursing and patient outcomes as it leads to losing competent and qualified nurses. However, developments of coping strategies demand a clear understanding of workplace variables that either motivate nurses to remain employed or lead them to leave their current jobs. Objective. This study was designed toassess factors influencing job satisfaction and intention to turnover among nurses in Sidama zone public health facilities, in Southern Ethiopia. Method. Cross-sectional study design was carried out on 278 nurses using both qualitative and quantitative data collection methods from May 12 to June 05, 2010. Result. A total of 242 nurses were interviewed giving a response rate of 87%. Nearly two-third (68.6% of the participants were female, and the mean age was 28 (±6.27 years for both sexes. All job satisfaction subscale except benefit and salary subscale were significant predictors of overall job satisfaction. Satisfactions with work environment and group cohesion (AOR: 0.25 [95% CI: 0.12, 0.51], single cohesion (AOR: 2.56 [95% CI: 1.27, 5.13], and working in hospital (AOR: 2.19 [95% CI: 1.12, 4.30] were the final significant predictors of anticipated turnover of Sidama zone nurses. Conclusions. More than any factors managers should consider the modification of working environment and group cohesions rather than trying to modify nurses to retain and maintain more experienced nurses for the organizations.

  16. Macrobenthos in anthropogenically influenced zones of a coralline marine protected area in the Gulf of Kachchh, India

    Science.gov (United States)

    Sukumaran, Soniya; Vijapure, Tejal; Mulik, Jyoti; Rokade, M. A.; Gajbhiye, S. N.

    2013-02-01

    The Gulf of Kachchh Marine National Park and Sanctuary (MNPS) has one of the four coral reef systems of India. However, owing to its unique geographical position, this area has been transformed into an industrial hub dominated by oil and gas production, refining and transportation facilities. This study investigates the status of macrobenthos along with associated hydro-sedimentological data at 30 stations, sampled within three industrially active zones of the MNPS. The bottom water and sediment characteristics recorded in the study area fulfil the prescribed criteria for ecosensitive zones of India, despite the various stressors operational in the region. The univariate parameters suggest a healthy macrobenthic community except for a few pockets of stressed environment. However, CCA and correlation analyses indicate that even at low levels, petroleum hydrocarbons, along with sediment texture, were influencing polychaete community structure. As this protected area is denoted a "high oil spill risk area", polychaete/amphipod ratio was employed to verify the environmental status which revealed that a major part of the study area had a good representation of oil-sensitive amphipods. The current study is the first of its kind to provide valuable baseline data of macrobenthos along with prevailing environmental conditions in this ecosensitive area.

  17. Contact models of repaired articular surfaces: influence of loading conditions and the superficial tangential zone.

    Science.gov (United States)

    Owen, John R; Wayne, Jennifer S

    2011-07-01

    The superficial tangential zone (STZ) plays a significant role in normal articular cartilage's ability to support loads and retain fluids. To date, tissue engineering efforts have not replicated normal STZ function in cartilage repairs. This finite element study examined the STZ's role in normal and repaired articular surfaces under different contact conditions. Contact area and pressure distributions were allowed to change with time, tension-compression nonlinearity modeled collagen behavior in the STZ, and nonlinear geometry was incorporated to accommodate finite deformation. Responses to loading via impermeable and permeable rigid surfaces were compared to loading via normal cartilage, a more physiologic condition, anticipating the two rigid loading surfaces would bracket that of normal. For models loaded by normal cartilage, an STZ placed over the inferior repair region reduced the short-term axial compression of the articular surface by 15%, when compared to a repair without an STZ. Covering the repair with a normal STZ shifted the flow patterns and strain levels back toward that of normal cartilage. Additionally, reductions in von Mises stress (21%) and an increase in fluid pressure (13%) occurred in repair tissue under the STZ. This continues to show that STZ properties of sufficient quality are likely critical for the survival of transplanted constructs in vivo. However, response to loading via normal cartilage did not always fall within ranges predicted by the rigid surfaces. Use of more physiologic contact models is recommended for more accurate investigations into properties critical to the success of repair tissues.

  18. Land use influence on 3-D distribution of soil microbiological activity in forest-steppe zone of Central Russia

    Science.gov (United States)

    Vasenev, Viacheslav; Tembo, Alan; Sarzhanov, Dmirty; Sotnikova, Julia; Ryzhkov, Oleg; Lakeev, Pavel; Valentini, Riccardo

    2014-05-01

    Land use is the principal factor influencing soil environmental functions and quality. Quite a few studies on soil quality mainly focus on natural and agroecosystems. Much less is known about urban ecosystems, although the urbanization effect on soil quality can be considerable. Parameters of soil microbiological activity are very sensitive to land-use change. Microbial biomass carbon (Cmic), basal respiration (BR) and microbial metabolic coefficient (qCO2) are among most widely used parameters of soil microbiological activity. They are directly associated with such soil functions as fertility, microorganisms' habitat and participation in carbon cycle. So far, most of the studies focus on the effect of land-use change on the topsoil (0-10 cm) microbiological activity, averaged for different land-use types. Much less is known about changes in spatial variability and profile distribution of Cmic, BR and qCO2 in response to different land-use. Land-use influence on spatial and profile distribution of soil microbiological activity may differ between bioclimatic zones. Very fertile and rich in carbon Chernozemic soils (depth of the A horizon up to 1 m, carbon concentration up to 7-9%), dominating in forest-steppe zone are among the most sensitive to land-use change. This study aims to improve understanding of land-use influence on 3-D distribution of Cmic, BR and qCO2 in Central Chernozemic region of Russia. We observed three land-use types (fallow land, natural pasture and meadow) located in Kursk region and three contrast urban functional zone (industrial, residential and recreational) in Kursk city. Soil samples were collected by auguring in five replicas per land-use type, four layers each sampling point (0-10, 10-50, 50-100 and 100-150 cm). Cmic, BR and qCO2 as well as Corg, N and pHKCl were analyzed in all the samples. Cmic (µg C g-1 soil) was analyzed based on the substrate induced respiration (SIR) approach. qCO2 (μg CO2-C mg-1 Cmic h-1) was calculated as the

  19. Burial Duration and Frequency Influences Resilience of Differing Propagule Types in a Subtidal Seagrass, Posidonia australis.

    Directory of Open Access Journals (Sweden)

    Marnie L Campbell

    Full Text Available Sedimentation that leads to periodic, and often prolonged, burial events is becoming more common on the world's coastlines as human populations expand and create urbanised marine environments. Different seagrass species react differently to sediment burial but many species in the southern hemisphere are yet to be examined. How seagrasses react to burial has restoration implications. There is a need to critically assess seagrass transplant propagule responses to periodic (pulse and prolonged (press burial events before selecting the most appropriate species, transplant propagule, and transplant site. In my study, mesocosm experiments, coupled with field measurements were used to assess how sexual (seedlings and vegetative (sprigs propagules of Posidonia australis responded to pulse and press burial events. Seedlings were highly susceptible to burial (both pulse and press, with no survival at the end of the experimental period. In contrast, rhizome growth in vegetative propagules was stimulated by pulse burial, although press burial events resulted in mortality. The implication for Posidonia australis restoration efforts in areas where burial is periodic, was that vegetative propagules are optimal transplant units, in comparison to seedlings. Press burial however, renders a transplant site sub-optimal for both seedling and sprig transplants.

  20. Burial Duration and Frequency Influences Resilience of Differing Propagule Types in a Subtidal Seagrass, Posidonia australis.

    Science.gov (United States)

    Campbell, Marnie L

    2016-01-01

    Sedimentation that leads to periodic, and often prolonged, burial events is becoming more common on the world's coastlines as human populations expand and create urbanised marine environments. Different seagrass species react differently to sediment burial but many species in the southern hemisphere are yet to be examined. How seagrasses react to burial has restoration implications. There is a need to critically assess seagrass transplant propagule responses to periodic (pulse) and prolonged (press) burial events before selecting the most appropriate species, transplant propagule, and transplant site. In my study, mesocosm experiments, coupled with field measurements were used to assess how sexual (seedlings) and vegetative (sprigs) propagules of Posidonia australis responded to pulse and press burial events. Seedlings were highly susceptible to burial (both pulse and press), with no survival at the end of the experimental period. In contrast, rhizome growth in vegetative propagules was stimulated by pulse burial, although press burial events resulted in mortality. The implication for Posidonia australis restoration efforts in areas where burial is periodic, was that vegetative propagules are optimal transplant units, in comparison to seedlings. Press burial however, renders a transplant site sub-optimal for both seedling and sprig transplants.

  1. Subtidal inner shelf currents off Cartagena de Indias, Caribbean coast of Colombia

    Science.gov (United States)

    Maza, Mauro; Voulgaris, George; Subrahmanyam, Bulusu

    2006-11-01

    Seasonal trends in inner shelf subtidal circulation off the coast of Cartagena de Indias, Colombia, are examined through the analysis of current profiles, hydrographic, meteorological and satellite data collected from 1999 to 2002. During the dry season (December-April) the water column is well-mixed and along-shelf currents flow southwestward following the steady trade winds. In the rainy season (May-November) the water column experiences continuous events of stratification and the along-shelf currents flow northeastward, opposing the weak southwestward winds. In the dry season the along-shelf circulation is mostly driven by wind forcing, while in the rainy season, the circulation is set by an alongshore baroclinic pressure gradient. In the cross-shelf direction upwelling conditions are observed most of the year and geostrophic balance conditions are found.

  2. Influence of Alkaline Co-Contaminants on Technetium Mobility in Vadose Zone Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Jansik, Danielle P.; McKinley, James P.; Hess, Nancy J.

    2014-09-01

    Pertechnetate was slowly reduced in a natural, untreated arid sediment under anaerobic conditions (0.02 nmol g-1 h-1), which could occur in low permeability zones in the field, most of which was quickly oxidized. A small portion of the surface Tc may be incorporated into slowly dissolving surface phases, so was not readily oxidized/remobilized into pore water. In contrast, pertechnetate reduction in an anaerobic sediment containing adsorbed ferrous iron as the reductant was rapid (15 to 600 nmol g-1 h-1), and nearly all (96 - 98%) was rapidly oxidized/remobilized (2.6 to 6.8 nmol g-1 h-1) within hours. Tc reduction in an anaerobic sediment containing 0.5 to 10 mM sulfide showed a relatively slow reduction rate (0.01 to 0.03 nmol g-1 h-1) that was similar to observations in the natural sediment. Pertechnetate infiltration into sediment with a highly alkaline water resulted in rapid reduction (0.07 to 0.2 nmol g-1 h-1) from ferrous iron released during biotite or magnetite dissolution. Oxidation of NaOH-treated sediments resulted in slow Tc oxidation (~0.05 nmol g-1 h-1) of a small fraction of the surface Tc (13% to 23%). The Tc remaining on the surface was TcIV (by XANES), and autoradiography and elemental maps of Tc (by electron microprobe) showed Tc was present associated with specific minerals, rather than being evenly distributed on the surface. Dissolution of quartz, montmorillonite, muscovite, and kaolinite also occurred in the alkaline water, resulting in significant aqueous silica and aluminum. Over time, aluminosilicates cancrinite, zeolite and sodalite were precipitating. These precipitates may be coating surface Tc(IV) phases, limiting reoxidation.

  3. Influence of alkaline co-contaminants on technetium mobility in vadose zone sediments.

    Science.gov (United States)

    Szecsody, Jim E; Jansik, Danielle P; McKinley, James P; Hess, Nancy J

    2014-09-01

    Pertechnetate was slowly reduced in a natural, untreated arid sediment under anaerobic conditions (0.02 nmolg(-1)h(-1)), which could occur in low permeability zones in the field, most of which was quickly oxidized. A small portion of the surface Tc may be incorporated into slowly dissolving surface phases, so was not readily oxidized/remobilized into pore water. In contrast, pertechnetate reduction in an anaerobic sediment containing adsorbed ferrous iron as the reductant was rapid (15-600 nmolg(-1)h(-1)), and nearly all (96-98%) was rapidly oxidized/remobilized (2.6-6.8 nmolg(-1)h(-1)) within hours. Tc reduction in an anaerobic sediment containing 0.5-10mM sulfide showed a relatively slow reduction rate (0.01-0.03 nmolg(-1)h(-1)) that was similar to observations in the natural sediment. Pertechnetate infiltration into sediment with a highly alkaline water resulted in rapid reduction (0.07-0.2 nmolg(-1)h(-1)) from ferrous iron released during biotite or magnetite dissolution. Oxidation of NaOH-treated sediments resulted in slow Tc oxidation (∼0.05 nmolg(-1)h(-1)) of a small fraction of the surface Tc (13-23%). The Tc remaining on the surface was Tc(IV) (by XANES), and autoradiography and elemental maps of Tc (by electron microprobe) showed Tc was present associated with specific minerals, rather than being evenly distributed on the surface. Dissolution of quartz, montmorillonite, muscovite, and kaolinite also occurred in the alkaline water, resulting in significant aqueous silica and aluminum. Over time, aluminosilicates, cancrinite, zeolite and sodalite were precipitating. These precipitates may be coating surface Tc(IV) phases, limiting reoxidation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Increased sediment load during a large-scale dam removal changes nearshore subtidal communities

    Science.gov (United States)

    Rubin, Stephen P.; Miller, Ian M.; Foley, Melissa M.; Berry, Helen D.; Duda, Jeffrey J.; Hudson, Benjamin; Elder, Nancy E.; Beirne, Matthew M.; Warrick, Jonathan; McHenry, Michael L.; Stevens, Andrew; Eidam, Emily; Ogston, Andrea; Gelfenbaum, Guy R.; Pedersen, Rob

    2017-01-01

    The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth). Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

  5. A thermal subtidal model for a well-mixed estuary based on field data

    Science.gov (United States)

    Padilla, Enrique M.; Díez-Minguito, Manuel; Ortega-Sánchez, Miguel; Genua-Olmedo, Ana; Losada, Miguel A.

    2013-04-01

    In this meeting, we will present a predictive model for the spatio-temporal variability of the temperature in a well-mixed estuary: The Guadalquivir river estuary, which is located in SW Spain and flows into the northern Gulf of Cádiz (Atlantic Ocean). It is a convergent, relatively narrow, navigable and positive estuary normally subjected to low freshwater discharges mainly released from the Alcalá del Río head dam, located 110 km inland. The tidally- and cross-sectionally averaged advection-diffusion equation for the thermal energy balance was integrated numerically by stretches defined by the moorings' locations. The model operates at the momentum-conveying part of the cross-section at subtidal scale, and is based on a data set from a comprehensive monitoring campaign carried out during 2008-2011 (Navarro et al., Ocean Dynamics 61 (6) 753-765, 2011). The thermal energy transport model is forced by radiative, atmospheric, tidal and fluvial data series. In particular, the time evolution of short and longwave radiation, and latent and sensible heat were obtained at different locations along channel (Pawlowicz et al. Eos Trans. AGU 82 (1), 2, 2001). Hindcast water surface temperature resulted in close agreement with observations in all locations, reaching a correlation higher than 0.99. The most important contributions to temperature variability, which exhibits evident subtidal and seasonal modulations, are radiation and advection. This is in agreement with recent results near the estuary mouth (García-Lafuente et al. Estuarine, Coastal and Shelf Science 111, 60-66, 2012). Results of the model indicate that water surface temperature along the main channel is weakly dependent on dispersion and freshwater discharges. Sea water temperature is a crucial factor that affects density, oxygen solubility, nutrients distribution and plankton migrations. Thus, present and future works focus on investigating the primary and secondary production evolution along the

  6. Increased sediment load during a large-scale dam removal changes nearshore subtidal communities.

    Directory of Open Access Journals (Sweden)

    Stephen P Rubin

    Full Text Available The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx-over 10 million tonnes-during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth. Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

  7. Subtidal sea level variability in a shallow Mississippi River deltaic estuary, Louisiana

    Science.gov (United States)

    Snedden, G.A.; Cable, J.E.; Wiseman, W.J.

    2007-01-01

    The relative roles of river, atmospheric, and tidal forcings on estuarine sea level variability are examined in Breton Sound, a shallow (0.7 m) deltaic estuary situated in an interdistributary basin on the Mississippi River deltaic plain. The deltaic landscape contains vegetated marshes, tidal flats, circuitous channels, and other features that frictionally dissipate waves propagating through the system. Direct forcing by local wind stress over the surface of the estuary is minimal, owing to the lack of significant fetch due to landscape features of the estuary. Atmospheric forcing occurs almost entirely through remote forcing, where alongshore winds facilitate estuary-shelf exchange through coastal Ekman convergence. The highly frictional nature of the deltaic landscape causes the estuary to act as a low-pass filter to remote atmospheric forcing, where high-frequency, coastally-induced fluctuations are significantly damped, and the damping increases with distance from the estuary mouth. During spring, when substantial quantities of controlled Mississippi River inputs (q?? = 62 m3 s-1) are discharged into the estuary, upper estuary subtidal sea levels are forced by a combination of river and remote atmospheric forcings, while river effects are less clear downestuary. During autumn (q?? = 7 m3 s-1) sea level variability throughout the estuary is governed entirely by coastal variations at the marine boundary. A frequency-dependent analytical model, previously used to describe sea level dynamics forced by local wind stress and coastal forcing in deeper, less frictional systems, is applied in the shallow Breton Sound estuary. In contrast to deeper systems where coastally-induced fluctuations exhibit little or no frictional attenuation inside the estuary, these fluctuations in the shallow Breton Sound estuary show strong frequency-dependent amplitude reductions that extend well into the subtidal frequency spectrum. ?? 2007 Estuarine Research Federation.

  8. Increased sediment load during a large-scale dam removal changes nearshore subtidal communities.

    Science.gov (United States)

    Rubin, Stephen P; Miller, Ian M; Foley, Melissa M; Berry, Helen D; Duda, Jeffrey J; Hudson, Benjamin; Elder, Nancy E; Beirne, Matthew M; Warrick, Jonathan A; McHenry, Michael L; Stevens, Andrew W; Eidam, Emily F; Ogston, Andrea S; Gelfenbaum, Guy; Pedersen, Rob

    2017-01-01

    The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx-over 10 million tonnes-during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth). Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

  9. Environmental and bathymetric influences on abyssal bait-attending communities of the Clarion Clipperton Zone

    Science.gov (United States)

    Leitner, Astrid B.; Neuheimer, Anna B.; Donlon, Erica; Smith, Craig R.; Drazen, Jeffrey C.

    2017-07-01

    The Clarion-Clipperton Zone (CCZ) is one of the richest manganese nodule provinces in the world and has recently become a focus area for manganese nodule mining interests. However, this vast area remains poorly studied and highly undersampled. In this study, the abyssal bait-attending fauna is documented for the first time using a series of baited camera deployments in various locations across the CCZ. A bait-attending community intermediate between those typical of the California margin and Hawaii was found in the larger CCZ area, generally dominated by rattail fishes, dendrobranchiate shrimp, and zoarcid and ophidiid fishes. Additionally, the western and eastern ends of the CCZ had different communities, with the western region characterized by decreased dominance of rattails and small shrimps and increased dominance of ophidiids (especially Bassozetus sp. and Barathrites iris) and large shrimps. This trend may be related to increasing distance from the continental margin. We also test the hypothesis that bait-attending communities change across the CCZ in response to key environmental predictors, especially topography and nodule cover. Our analyses showed that higher nodule cover and elevated topography, as quantified using the benthic positioning index (BPI), increase bait-attending community diversity. Elevated topography generally had higher relative abundances, but taxa also showed differing responses to the BPI metric and bottom temperature, causing significant community compositional change over varying topography and temperatures. Larger individuals of the dominant scavenger in the CCZ, Coryphaenoides spp., were correlated with areas of higher nodule cover and with abyssal hills, suggesting these areas may be preferred habitat. Our results suggest that nodule cover is important to all levels of the benthic ecosystem and that nodule mining could have negative impacts on even the top-level predators and scavengers in the CCZ. Additionally, there is

  10. Influence of landfast ice on the hydrography and circulation of the Baltic Sea coastal zone

    Directory of Open Access Journals (Sweden)

    Ioanna Merkouriadi

    2013-02-01

    Full Text Available The influence of landfast ice on hydrography and circulation is examined inSantala Bay, adjacent to the Hanko Peninsula, Gulf of Finland. Three-dimensionalelectromagnetic current meters and conductivity-temperature-depth (CTD sensorswere deployed in winters 1999-2000 and 2000-2001 during the Finnish-Japanese"Hanko 9012" experiment. In each winter, data collection started one month beforethe initial ice formation and lasted until one month after the ice had meltedcompletely. Temperature and salinity are compared with long-term data from theTvärminne Zoological Station, also located on the Hanko Peninsula. Thewater temperature was 2°C less than the long-term average. Iceformation and melting show up in the salinity evolution of the water body,which makes salinity a good indicator of ice formation and breakup in SantalaBay. The circulation under the ice became weaker by almost 1 cm s-1.

  11. Dynamics of interplate domain in subduction zones: influence of rheological parameters and subducting plate age

    Directory of Open Access Journals (Sweden)

    D. Arcay

    2012-12-01

    Full Text Available The properties of the subduction interplate domain are likely to affect not only the seismogenic potential of the subduction area but also the overall subduction process, as it influences its viability. Numerical simulations are performed to model the long-term equilibrium state of the subduction interplate when the diving lithosphere interacts with both the overriding plate and the surrounding convective mantle. The thermomechanical model combines a non-Newtonian viscous rheology and a pseudo-brittle rheology. Rock strength here depends on depth, temperature and stress, for both oceanic crust and mantle rocks. I study the evolution through time of, on one hand, the brittle-ductile transition (BDT depth, zBDT, and, on the other hand, of the kinematic decoupling depth, zdec, simulated along the subduction interplate. The results show that both a high friction and a low ductile strength at the asthenospheric wedge tip shallow zBDT. The influence of the weak material activation energy is of second order but not negligible. zBDT becomes dependent on the ductile strength increase with depth (activation volume if the BDT occurs at the interplate decoupling depth. Regarding the interplate decoupling depth, it is shallowed (1 significantly if mantle viscosity at asthenospheric wedge tip is low, (2 if the difference in mantle and interplate activation energy is weak, and (3 if the activation volume is increased. Very low friction coefficients and/or low asthenospheric viscosities promote zBDT = zdec. I then present how the subducting lithosphere age affects the brittle-ductile transition depth and the kinematic decoupling depth in this model. Simulations show that a rheological model in which the respective activation energies of mantle and interplate material are too close hinders the mechanical decoupling at the down-dip extent of the interplate

  12. The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones

    Directory of Open Access Journals (Sweden)

    N. Cassar

    2011-02-01

    Full Text Available The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ and the northern reaches of the Polar Frontal Zone (PFZ, we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m, dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. The strong correlation between NCP and dissolved Fe may be difficult to interpret because of the correlation of dissolved Fe to MLD and because the concentration of iron may not be a good indicator of its availability. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.

  13. Population ecology and community structure of sub-tidal soft sediment dwelling macro-invertebrates of Konkan, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Vizakat; Harkantra, S.N.; Parulekar, A.H.

    macro-invertebrates in the sub-tidal region of Konkan coast. The model put forward by Huston [Am. Nat. 113 (1879) 101] is most convicing to explain the benthic population and community structure dynamics....

  14. The influence of plant communities on postagrogenic soils in the middle taiga zone.

    Science.gov (United States)

    Churilin, Nikita; Churilina, Alexandra; Chizhikova, Natalia; Varlamov, Evgeny

    2016-04-01

    decreases with crown density, therefore clay doesn't migrate to the underlying horizons in the soil. Over time, acid aqueous solution can influence on process of clay fraction redistribution, so it explains the reduction of clay content in the old spruce forest and well-defined albic horizon. The results of chemical analyses showed that pH of these soils varies between 3 and 4. In all soils we can see illuvial accumulation of P2O5, exchangeable bases, K2O, Fe2O3. It was also shown that carbonates are present in horizons close to the subsoil, which content is less than 1%.

  15. Response of soil microflora to impact of heavy metals in zones of influence of railway transport

    Directory of Open Access Journals (Sweden)

    N. Bobryk

    2016-03-01

    Full Text Available Monitoring research on the areas intensively and continuously affected by technogenic loading has remained topical until nowadays. The soil as a basic component of many ecosystems, including the structure of its microbial cenoses, remains an informative index of a system’s overall stability. The areas affected by railway transport have been scarcely studied. Due to the above, the aim of this work has been to establish the transformation regularities of soil microbial cenoses of territories close to railways and to establish the groups of microorganisms that are a sensitive criterion of technogenic vehicular influence. For the purpose of microbiological research, soil samples were taken at different distances from the railway track (0, 25, 50, 100 and250 m within five monitoring sections of the Tchop – Uzhhorod – Sambor railway (in the territory of Zakarpatska oblast. The number of ecological trophic groups was identified by means of inoculation on nutrient media using the method of serial dilution of soil suspensions. The research showed that in all types of soils that were adjacent to railway tracks, the number of ammonifiers and spore microbiota was high due to the high content of heavy metals (beyond the background levels. Besides, the bacterial microflora on beef-extract agar was characterized by homogeneity with domination of enteric bacteria and spore bacteria. Simultaneously, the numbers of nitrogen-fixing microorganisms, micromycetes, oligonitrophils, amylolytic and pedotrophic microflorae were shown to be low compared to the control. Farther from the railway track, pigmental species of bacteria appeared in the soil samples, attesting to the activity of self-purification processes. Correlation analysis of the data showed that the soil microbiota of the railway-side areas was undergoing changes as affected by heightened contents of heavy metals. Existence of medium and close connections was established between the number of

  16. H51E-1535: Biogeochemical factors influencing the transport and fate of colloids and colloid-associated contaminants in the vadose zone

    Science.gov (United States)

    The vadose zone exhibits large spatial and temporal variability in many physical, chemical, and biological factors that strongly influence the transport and fate of colloids (e.g., microbes, nanoparticles, clays, and dissolved organic matter) and colloid-associated contaminants (e.g., heavy metals, ...

  17. On the Influence of Particle Entrainment from an Inhomogeneous Fluidized Bed on the Hydrodynamics of the Vortex Over-Bed Zone

    Science.gov (United States)

    Pitsukha, E. A.; Teplitskii, Yu. S.

    2017-01-01

    Experimental investigation of the radial distributions of tangential air velocity and total pressure in the vortex overbed zone of a fluidized bed of diameter 0.393 m has been carried out. The influence of the entrainment of particles from the bed in the exhaust trails of gas bubbles on the maximum values of tangential velocity and total pressure has been established.

  18. The Times They Are A-Changing: The Influence of Railroad Technology on the Adoption of Standard Time Zones in 1883.

    Science.gov (United States)

    Allen, Nathaniel

    2000-01-01

    Presents the story of the role railroad technology had in the adoption of Standard Time Zones in 1883 and also considers the influence of astronomers at the time. Includes the map of the standard railway time used by W. F. Allen and an annotated bibliography with primary and secondary sources. (CMK)

  19. Lengthening of insect development on Bt zone results in adult emergence asynchrony: does it influence the effectiveness of the high dose/refuge zone strategy?

    Science.gov (United States)

    Gryspeirt, Aiko; Grégoire, Jean-Claude

    2012-11-15

    The “High Dose/Refuge” strategy (HD/R) is the currently recommended Insect Resistance Management strategy (IRM) to limit resistance development to Bacillus thuringiensis (Bt) plants. This strategy requires planting a “refuge zone” composed of non-Bt plants suitable for the target insect and in close proximity to a “Bt zone” expressing a high toxin concentration. One of the main assumptions is that enough susceptible adults mate with resistant insects. However, previous studies have suggested that the high toxin concentration produced by Bt plants induces slower insect development, creating an asynchrony in emergence between the refuge and the Bt zone and leading to assortative mating between adults inside each zone. Here, we develop a deterministic model to estimate the impact of toxin concentration, emergence asynchrony and refuge zone size on the effectiveness of the HD/R strategy. We conclude that emergence asynchrony only affects resistance when toxin concentration is high and resistance is recessive. Resistance develops more rapidly and survival of susceptible insects is higher at lower toxin concentration, but in such situations, resistance is insensitive to emergence asynchrony.

  20. Reversal of subtidal dune asymmetries caused by seasonally reversing wind-driven currents in Torres Strait, northeastern Australia

    Science.gov (United States)

    Harris, Peter T.

    1991-07-01

    Large subtidal sand dunes (sandwaves) located in Adolphus Channel, Torres Strait, have been observed to reverse their asymmetric orientation between September-February. This has been attributed to a reversal in wind-driven currents, which flow westward during the SE trade season (April-November) and eastwards during the NW monsoon season [December-March: HARRIS (1989) Continental Shelf Research, 9, 981-1002]. Observations in September 1988 and February 1989 from another area of dunes in Torres Strait corroborate this asymmetry reversal pattern. The results indicate that such reversals may be common in Torres Strait and in other areas where subtidal bedforms are subject to modification by superimposed, seasonally reversing, wind-driven currents.

  1. Bottom trawling and oxygen minimum zone influences on continental slope benthic community structure off Vancouver Island (NE Pacific)

    Science.gov (United States)

    De Leo, Fabio C.; Gauthier, Maéva; Nephin, Jessica; Mihály, Steven; Juniper, S. Kim

    2017-03-01

    Understanding responses of benthic ecosystems to cumulative impacts of natural stressors, long-term ocean change and increasing resource exploitation is an emerging area of interest for marine ecologists and environmental managers. Few, if any, studies have quantitatively addressed cumulative effects in the deep sea. We report here on a study from the continental slope off Vancouver Island (Canada) in the northeast Pacific Ocean, where the Oxygen Minimum Zone impinges on seabed habitats that are subjected to widespread bottom trawling, primarily by the fishery for thornyhead (Sebastolobus ssp.). We examined how the benthic megafauna in this area was influenced by varying levels of dissolved oxygen and trawling activity, along a depth gradient that was also likely to shape community composition. Continuous video and sonar records from two ROV surveys (50 linear km total; depth range 300-1400 m) respectively provided data on faunal attributes (composition, abundance and diversity) and the frequency of trawl door marks on the seabed. Faunal and trawl data were compiled in a geo-referenced database along with corresponding dissolved oxygen data, and pooled into 500 m segments for statistical analysis. Trawl mark occurrence peaked between 500 and 1100 m, corresponding to areas of slope subjected to hypoxia (multiple regression (DISTLM) models. Species richness was highest at intermediate depths and in areas subject to intermediate levels of trawling, and higher under hypoxia than under severe hypoxia. These statistically significant trends demonstrate that the structuring influences of bottom trawling on deep-sea benthic communities can be observed even where communities are being shaped by strong environmental gradients.

  2. Evaluation of the Zone of Influence and Entrainment Impacts for an Intake Using a 3-Dimensional Hydrodynamic and Transport Model

    Directory of Open Access Journals (Sweden)

    Shwet Prakash

    2014-04-01

    Full Text Available Ballast water systems in large LNG carriers are essential for proper operations and stability. Water withdrawn from the surrounding environment to supply to the ballast can pose entrainment and impingement risk to the resident fish population. Quantification of these risks and the net effect on population is usually quite challenging and complex. Various methods over the last several decades have been developed and are available in the literature for quantification of entrainment of mobile and immobile lifestages of resident fish. In this study, a detailed 3-dimensional model was developed to estimate the entrainment of ichthyoplankton (fish eggs and larvae and fish from an estuarine environment during the repeated short-term operation of a ballast water intake for an LNG carrier. It was also used to develop a zone of influence to determine the ability of mobile life stages to avoid impingement. The ichthyoplankton model is an Equivalent Adult Model (EAM and assesses the number of breeding adults lost to the population. The EAM incorporates four different methods developed between 1978 and 2005. The study also considers the uncertainty in estimates for the lifestage data and, as such, performs sensitivity analyses to evaluate the confidence level achievable in such quantitative estimates for entrainment.

  3. Abundance, distribution and feeding patterns of a temperate reef fish in subtidal environments of the Chilean coast: the importance of understory algal turf Abundancia, distribución y patrones alimentarios de un pez de arrecifes templados en ambientes submareales de la costa de Chile: la importancia de la capa de algas del subdosel

    Directory of Open Access Journals (Sweden)

    ÁLVARO T. PALMA

    2002-03-01

    Full Text Available Cheilodactylus variegatus is an abundant carnivorous demersal reef fish that lives in the shallow subtidal of the north-central Chilean coast. Characteristically, these environments are dominated by kelp forests of Lessonia trabeculata. This species preys on a great variety of benthic invertebrates, and shows particularly high consumption rates on amphipod crustaceans. In our study, two widely separated populations of C. variegatus were considered (central and northern Chile. Individuals that form part of these populations show considerable differences in their distribution, abundance and trophic behavior. In the northern zone, the species is abundant and both juveniles and adults are distributed along the whole bathymetric gradient. This contrasts with populations found in central Chile, which are more sparse and lack juveniles. The distribution and abundance patterns appear to be influenced mainly by the great abundance of diverse understory macroalgae in the northern subtidal, which harbors a large number of invertebrates, especially amphipods. In contrast, the understory algal abundance of the central zone is much lower, and does not show a direct relationship with the lesser abundance of amphipods. In general, C. variegatus maintains a high consumption rate on amphipods throughout its ontogeny but it includes several other prey items in later ontogenetic stages. The different understory algal assemblages, and their associated fauna, are likely to be the main factors influencing the patterns of abundance and distribution observed between these two geographically distinct fish populationsCheilodactylus variegatus es un pez demersal abundante que habita el submareal somero de la costa norte y central de Chile. Es característico de estos ambientes el estar dominados por praderas del alga Lessonia trabeculata. Esta especie incorpora en su dieta una variada gama de invertebrados bentónicos, mostrando una tasa particularmente alta de consumo de

  4. Documenting the density of subtidal marine debris across multiple marine and coastal habitats.

    Science.gov (United States)

    Smith, Stephen D A; Edgar, Robert J

    2014-01-01

    Marine debris is recognised globally as a key threatening process to marine life, but efforts to address the issue are hampered by the lack of data for many marine habitats. By developing standardised protocols and providing training in their application, we worked with >300 volunteer divers from 11 underwater research groups to document the scale of the subtidal marine debris problem at 120 sites across >1000 km of the coast of NSW, Australia. Sampling consisted of replicated 25×5 m transects in which all debris was identified, counted, and, where appropriate, removed. Sites ranged from estuarine settings adjacent to major population centres, to offshore islands within marine parks. Estuaries and embayments were consistently found to be the most contaminated habitats. Fishing-related items (and especially monofilament and braided fishing line) were most prevalent at the majority of sites, although food and drink items were important contributors at sites adjacent to population centres. The results identified damaging interactions between marine debris and marine biota at some key locations, highlighting the need for management intervention to ensure habitat sustainability. This study reinforces the important contribution that volunteers can make to assessing conservation issues requiring broad-scale data collection. In this case, citizen scientists delivered data that will inform, and help to prioritise, management approaches at both statewide and local scales. These initial data also provide an important baseline for longer-term, volunteer-based monitoring programs.

  5. Documenting the density of subtidal marine debris across multiple marine and coastal habitats.

    Directory of Open Access Journals (Sweden)

    Stephen D A Smith

    Full Text Available Marine debris is recognised globally as a key threatening process to marine life, but efforts to address the issue are hampered by the lack of data for many marine habitats. By developing standardised protocols and providing training in their application, we worked with >300 volunteer divers from 11 underwater research groups to document the scale of the subtidal marine debris problem at 120 sites across >1000 km of the coast of NSW, Australia. Sampling consisted of replicated 25×5 m transects in which all debris was identified, counted, and, where appropriate, removed. Sites ranged from estuarine settings adjacent to major population centres, to offshore islands within marine parks. Estuaries and embayments were consistently found to be the most contaminated habitats. Fishing-related items (and especially monofilament and braided fishing line were most prevalent at the majority of sites, although food and drink items were important contributors at sites adjacent to population centres. The results identified damaging interactions between marine debris and marine biota at some key locations, highlighting the need for management intervention to ensure habitat sustainability. This study reinforces the important contribution that volunteers can make to assessing conservation issues requiring broad-scale data collection. In this case, citizen scientists delivered data that will inform, and help to prioritise, management approaches at both statewide and local scales. These initial data also provide an important baseline for longer-term, volunteer-based monitoring programs.

  6. Experimental removal and recovery of subtidal grazers highlights the importance of functional redundancy and temporal context.

    Directory of Open Access Journals (Sweden)

    Robin Elahi

    Full Text Available The extent to which different grazers are functionally redundant has strong implications for the maintenance of community structure and function. Grazing by red urchins (Strongylocentrotus franciscanus on temperate rocky reefs can initiate a switch from invertebrate or macroalgal dominance to an algal crust state, but can also cause increases in the density of molluscan mesograzers. In this study, we tested the hypothesis that red urchins and lined chitons (Tonicella spp. are redundant in the maintenance of available space, defined as encrusting algae and bare rock. In a factorial field experiment replicated at three sites, we reduced the densities of urchins and chitons on subtidal rock walls for nine months. The effects of grazers were interpreted in the context of natural temporal variation by monitoring the benthic community one year before, during, and after grazer removal. The removal of each grazer in isolation had no effect on the epilithic community, but the removal of both grazers caused an increase in sessile invertebrates. The increase was due primarily to clonal ascidians, which displayed a large (∼75% relative increase in response to the removal of both grazers. However, the observed non-additive responses to grazer removal were temporary and smaller than seasonal fluctuations. Our data demonstrate that urchins and chitons can be redundant in the maintenance of available space, and highlight the value of drawing conclusions from experimental manipulations within an extended temporal context.

  7. Benthic assemblage composition on subtidal reefs along a latitudinal gradient in Western Australia

    Science.gov (United States)

    Smale, D. A.; Kendrick, G. A.; Waddington, K. I.; Van Niel, K. P.; Meeuwig, J. J.; Harvey, E. S.

    2010-01-01

    At regional scales, the distribution of species and the structure of assemblages vary with latitude within many marine and terrestrial systems. The oligotrophic coastal waters of Western Australia (WA) support highly speciose and endemic assemblages, yet spatial patterns in benthic structure are currently poorly known. We examined benthic assemblage composition along a latitudinal gradient of 28.5-33.5°S and a depth gradient of 14-62 m, on subtidal reefs in warm-temperate WA. We surveyed benthos using a remotely triggered digital stills camera. In total, we sampled macroalgae and sessile invertebrates at 201 sites spread across four locations. Percent cover of coarse taxonomic groups and dominant species was estimated from over 2000 photoquadrat samples. We recorded significant differences in benthic assemblage composition between locations, and along depth gradients within each location. However, the magnitude of change with depth was not consistent between locations, and shifts in assemblage composition along the depth gradients were not as pronounced as expected. The percent cover of all dominant benthic groupings differed between locations, and several key taxa, such as the kelp Scytothalia dorycarpa, brown foliose macroalgae, hard corals and sponges, changed predictably along the latitudinal gradient. Our study adopted a coarse taxonomic, but assemblage-wide, approach to describing macrobenthic assemblages, and clear differences between locations and depths were detected. The surveys have provided baseline data on broad scale ecosystem structure against which to detect future ecological change.

  8. High prevalence of diffusive uptake of CO2 by macroalgae in a temperate subtidal ecosystem.

    Science.gov (United States)

    Cornwall, Christopher E; Revill, Andrew T; Hurd, Catriona L

    2015-05-01

    Productivity of most macroalgae is not currently considered limited by dissolved inorganic carbon (DIC), as the majority of species have CO2-concentrating mechanisms (CCM) allowing the active uptake of DIC. The alternative, diffusive uptake of CO2 (non-CCM), is considered rare (0-9% of all macroalgal cover in a given ecosystem), and identifying species without CCMs is important in understanding factors controlling inorganic carbon use by eukaryotic algae. CCM activity has higher energetic requirements than diffusive CO2 uptake, therefore when light is low, CCM activity is reduced in favour of diffusive CO2 uptake. We hypothesized that the proportional cover of macroalgae without CCMs (red and green macroalgae) would be low (green macroalgae (two species). The proportion of non-CCM species increased with depth at three of four sites. 35% of species tested had significantly depleted δ(13)C values at deeper depths. Non-CCM macroalgae are more abundant in some temperate reefs than previously thought. If ocean acidification benefits non-CCM species, the ramifications for subtidal macroalgal assemblages could be larger than previously considered.

  9. Spatial patterns of sub-tidal seagrasses and their tissue nutrients in the Torres Strait, northern Australia: Implications for management

    Science.gov (United States)

    Sheppard, James K.; Carter, Alex B.; McKenzie, Len J.; Pitcher, C. Roland; Coles, Robert G.

    2008-09-01

    The distribution and nutritional profiles of sub-tidal seagrasses from the Torres Strait were surveyed and mapped across an area of 31,000 km 2. Benthic sediment composition, water depth, seagrass species type and nutrients were sampled at 168 points selected in a stratified representative pattern. Eleven species of seagrass were present at 56 (33.3%) of the sample points. Halophila spinulosa, Halophila ovalis, Cymodocea serrulata and Syringodium isoetifolium were the most common species and these were nutrient profiled. Sub-tidal seagrass distribution (and associated seagrass nutrient concentrations) was generally confined to northern-central and south-western regions of the survey area (sub-tidally in the Torres Strait. There were two regions in Torres Strait (north-central and south-western) where sub-tidal seagrass meadows were prevalent and of relatively higher

  10. Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones

    Science.gov (United States)

    Gil-Sotres, F.; Miralles, I.; Canton-Castilla, Y.; Domingo, F.; Leiros, M. C.; Trasar-Cepeda, C.

    2012-04-01

    Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones I. Miralles1, F. Gil-Sotres2, Y. Cantón-Castilla3, F. Domingo1, M.C. Leirós2, C. Trasar-Cepeda4 1 Experimental Estation of Arid Zones (CSIC), E-04230 La Cañada de San Urbano, Almería, Spain. 2 Departamento Edafología y Química Agrícola, Grupo de Evaluación de la Calidad del Suelo, Unidad Asociada CSIC, Facultad de Farmacia, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain. 3 University of Almería, Departamento de Edafología y Química Agrícola, E-04230-La Cañada de San Urbano, Almería, Spain. 4 Departamento Bioquímica del Suelo, IIAG-CSIC, Apartado 122, E-15708 Santiago de Compostela, Spain. Crusts (BSCs) are formed by a close association between soil particles and cyanobacteria, algae, lichens, bryophytes and microfungi in varying proportions. Their habitat is within or immediately on top of the uppermost millimetres of the soil and are the predominant surface cover in arid and semiarid zones. Among the diverse functions developed by BSCs in the ecosystem (hydrology, erosion, soil properties, etc.), one of the most important is its role in nutrient cycling. Within arid and semiarid environments, BSCs have been termed 'mantles of fertility' being considered hotspots of biogeochemical inputs, fixing C, N and P above- and below-ground. However, there are differences in N and C fixation rates between BSCs types. Early successional BSCs, dominated by cyanobacterial species, fix lower quantities of C and N than mature BSCs dominated by lichens. Although the positive effects of BSCs on biogeochemical soil cycles are widely accepted, no previous studies have evaluated the activities of the enzymes involved in C, N and P cycles of BSCs and how they are affected by the successional stage of the BSC. In this work, performed in the Tabernas desert (SE Spain), we studied the hydrolase enzymes

  11. Influence of atmospheric parameters on vertical profiles and horizontal transport of aerosols generated in the surf zone

    NARCIS (Netherlands)

    Kusmierczyk-Michulec, J.; Tedeschi, G.; Eijk, A.M.J. van; Piazzolac, J.

    2013-01-01

    The vertical and horizontal transport of aerosols generated over the surf zone is discussed. Experimental data were collected during the second campaign of the Surf Zone Aerosol Experiment that took place in Duck NC (USA) in November 2007. The Empirical Orthogonal Function (EOF) method was used to

  12. The influence of electron-beam welding parameters on heat-affected-zone microfissuring in INCOLOY 903

    Science.gov (United States)

    Richards, N. L.; Nakkalil, R.; Chaturvedi, M. C.

    1994-08-01

    The microfissuring in the heat-affected zone (HAZ) of electron-beam-(EB-) welded thermomechanically processed INCOLOY 903 has been studied with a view to reducing the incidence of microfissuring and to obtaining a better understanding of the influence of EB welding parameters on it. For a given heat of material, microfissuring susceptibility has been quantitatively related to EB welding parameters and the shape of the weld pool. Fractional factorial experimental study of welding parameters showed that a reduction in welding speed and an increase in EB current for a given heat input would minimize HAZ microfissuring in the alloy. It was observed that with lower travel speeds, bccause of the shallower temperature gradients in the HAZ, the amount of liquated grain boundary area is less, thus leading to decreased microfissuring. Considerable HAZ microfissuring was observed on the coarse grain boundaries of warm-worked grains. The microfissures appeared to initiate in regions slightly removed from the fusion line. Minimal microfissuring was observed on the grain boundaries of fine recrystallized grains. These boundaries, however, had a thickened appearance bccause of the formation of Nb-enriched y phase by the process of grain boundary liquid film migration (LFM). The origin of the liquid on the grain boundaries is suggested to be due to the constitutional liquation of preexisting primary carbides (partial), fine MC carbides, and MNP-type phosphides. It is suggested that substantial occurrence of LFM in the HAZ minimizes microfissuring by decreasing the total temperature range of solidification and also by enabling the grain boundary liquid to solidify without the occurrence of low-melting terminal eutectic reaction.

  13. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

    Science.gov (United States)

    Miller, J J; Bremer, E; Curtis, T

    2016-07-01

    Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. Influence of a dominant consumer species reverses at increased diversity.

    Science.gov (United States)

    Brandt, Margarita; Witman, Jon D; Chiriboga, Angel I

    2012-04-01

    Theory and experiments indicate that changes in consumer diversity affect benthic community structure and ecosystem functioning. Although the effects of consumer diversity have been tested in the laboratory and the field, little is known about effects of consumer diversity in the subtidal zone, one of the largest marine habitats. We investigated the grazing effects of sea urchins on algal abundance and benthic community structure in a natural subtidal habitat of the Galápagos Islands. Three species of urchins (Eucidaris, Lytechinus, and Tripneustes) were manipulated in inclusion cages following a replacement design with three levels of species richness (one, two, and three species) with all possible two-species urchin combinations. Identity was the main factor accounting for changes in the percentage of substrate grazed and benthic community structure. Two out of the three two-species assemblages grazed more than expected, suggesting a richness effect, but analyses revealed that this increased grazing was due to a sampling effect of the largest and commercially valued urchin species, Tripneustes. Benthic community structure in treatments with Eucidaris, Lytechinus, and Tripneustes alone was significantly different at the end of the experiment, suggesting that resource use differentiation occurred. Communities in Tripneustes enclosures were characterized by abundant crustose coralline algae and grazed substrate, while those without it contained abundant green foliose algae (Ulva sp.). An unexpected emergent property of the system was that the most species-rich urchin assemblage underyielded, grazing less than any other assemblage with Tripneustes, effectively reversing its dominant influence observed in the two-species treatments. While further experiments are needed to discern the mechanisms of underyielding, it may be related to changing interspecific interactions as richness increases from two to three species or to density-dependent Tripneustes grazing. This

  15. Levels and distributions of organic pollutants in subtidal sediments from the Loire estuary: Are there any relationships with TTR-binding activity?

    Science.gov (United States)

    Couderc, M.; Gandolfi, F.; Zalouk-Vergnoux, A.; Beyeler, N.; Malleret, L.; Ambidina, I.; Kamari, A.; Blanchet-Letrouvé, I.; Mouneyrac, C.; Hamers, T.; Poirier, L.

    2016-12-01

    The Loire estuary runs through important urban sites with shipping, industrial and agricultural activities, being the receptacle of diffusive pollutants comprising, a mixture of contaminants such as persistent organic pollutants (POPs). This work was set out to evaluate the occurrence of thyroid endocrine disruptors in sediments of this estuary. Sediments were collected in September 2012 and April 2013, in subtidal zones along the estuary. Targeted chemical analyses of five classes of pollutants, i.e. polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and bisphenol A (BPA) were performed in sediment extracts. Extracts were further tested for their thyroid hormone (TH) disrupting potency to compete with TH for binding to its transporter protein transthyretin (TTR). The Haute-Indre site was characterized by a significant PAH contamination whereas Saint-Nazaire, Bellevue and Rezé would be particularly contaminated by PCBs. These observations could be linked to the different type of anthropogenic activities taking place close to these sites. Donges, Mindin and Paimboeuf were the sampling sites displaying the lowest contamination in PAHs, APs, PCBs and PBDEs. No inter-site difference could be observed for TTR-binding activity, which should be attributed to different compounds than the chemically analyzed compounds, as confirmed by PCA analyses. Furthermore, the TTR-binding potencies of the extracts were relatively low compared to data from literature. More investigations on the quantification of PCB and PBDE hydroxylated metabolites and other known endocrine disruptors such as pesticides or perfluorinated compounds could be considered, as well as bioassays highlighting other endocrine disrupting effects.

  16. Assessment of groundwater potential zones using multi-influencing factor (MIF) and GIS: a case study from Birbhum district, West Bengal

    Science.gov (United States)

    Thapa, Raju; Gupta, Srimanta; Guin, Shirshendu; Kaur, Harjeet

    2017-11-01

    Remote sensing and GIS play a vital role in exploration and assessment of groundwater and has wide application in detection, monitoring, assessment, conservation and various other fields of groundwater-related studies. In this research work, delineation of groundwater potential zone in Birbhum district has been carried out. Various thematic layers viz. geology, geomorphology, soil type, elevation, lineament and fault density, slope, drainage density, land use/land cover, soil texture, and rainfall are digitized and transformed into raster data in ArcGIS 10.3 environment as input factors. Thereafter, multi-influencing factor (MIF) technique is employed where ranks and weights, assigned to each factor are computed statistically. Finally, groundwater potential zones are classified into four categories namely low, medium, high and very high zone. It is observed that 18.41% (836.86 km2) and 34.41% (1563.98 km2) of the study area falls under `low' and `medium' groundwater potential zone, respectively. Approximately 1601.19 km2 area accounting for 35.23% of the study area falls under `high' category and `very high' groundwater potential zone encompasses an area of 542.98 km2 accounting for 11.95% of the total study area. Finally, the model generated groundwater potential zones are validated with reported potential yield data of various wells in the study area. Success and prediction rate curve reveals an accuracy achievement of 83.03 and 78%, respectively. The outcome of the present research work will help the local authorities, researchers, decision makers and planners in formulating better planning and management of groundwater resources in the study area in future perspectives.

  17. Assessment of groundwater potential zones using multi-influencing factor (MIF) and GIS: a case study from Birbhum district, West Bengal

    Science.gov (United States)

    Thapa, Raju; Gupta, Srimanta; Guin, Shirshendu; Kaur, Harjeet

    2017-05-01

    Remote sensing and GIS play a vital role in exploration and assessment of groundwater and has wide application in detection, monitoring, assessment, conservation and various other fields of groundwater-related studies. In this research work, delineation of groundwater potential zone in Birbhum district has been carried out. Various thematic layers viz. geology, geomorphology, soil type, elevation, lineament and fault density, slope, drainage density, land use/land cover, soil texture, and rainfall are digitized and transformed into raster data in ArcGIS 10.3 environment as input factors. Thereafter, multi-influencing factor (MIF) technique is employed where ranks and weights, assigned to each factor are computed statistically. Finally, groundwater potential zones are classified into four categories namely low, medium, high and very high zone. It is observed that 18.41% (836.86 km2) and 34.41% (1563.98 km2) of the study area falls under `low' and `medium' groundwater potential zone, respectively. Approximately 1601.19 km2 area accounting for 35.23% of the study area falls under `high' category and `very high' groundwater potential zone encompasses an area of 542.98 km2 accounting for 11.95% of the total study area. Finally, the model generated groundwater potential zones are validated with reported potential yield data of various wells in the study area. Success and prediction rate curve reveals an accuracy achievement of 83.03 and 78%, respectively. The outcome of the present research work will help the local authorities, researchers, decision makers and planners in formulating better planning and management of groundwater resources in the study area in future perspectives.

  18. Factors influencing the prevalence and infestation levels of Varroa destructor in honeybee colonies in two highland agro-ecological zones of Uganda.

    Science.gov (United States)

    Chemurot, Moses; Akol, Anne M; Masembe, Charles; de Smet, Lina; Descamps, Tine; de Graaf, Dirk C

    2016-04-01

    Varroa mites are ecto-parasites of honeybees and are a threat to the beekeeping industry. We identified the haplotype of Varroa mites and evaluated potential factors that influence their prevalence and infestation levels in the eastern and western highland agro-ecological zones of Uganda. This was done by collecting samples of adult worker bees between December 2014 and September 2015 in two sampling moments. Samples of bees were screened for Varroa using the ethanol wash method and the mites were identified by molecular techniques. All DNA sequences obtained from sampled mite populations in the two zones were 100 % identical to the Korean Haplotype (AF106899). Mean mite prevalence in the apiaries was 40 and 53 % for the western and eastern zones, respectively, during the first sampling. Over the second sampling, mean mite prevalence increased considerably in the western (59 %) but not in the eastern (51 %) zone. Factors that were associated with Varroa mite infestation levels include altitude, nature of apiary slope and apiary management practices during the first sampling. Our results further showed that Varroa mites were spreading from lower to higher elevations. Feral colonies were also infested with Varroa mites at infestation levels not significantly different from those in managed colonies. Colony productivity and strength were not correlated to mite infestation levels. We recommend a long-term Varroa mite monitoring strategy in areas of varying landscape and land use factors for a clear understanding of possible changes in mite infestation levels among African honeybees for informed decision making.

  19. Short-term temporal dynamics of algal species in a subtidal kelp bed in relation to changes in environmental conditions and canopy biomass

    Science.gov (United States)

    Wernberg, Thomas; Goldberg, Nisse

    2008-01-01

    Understanding temporal variation at the scale of weeks to months is critical to understanding broad temporal patterns in diversity in the same way as understanding diversity across landscapes relies on understanding variation at the scale of meters. However, whereas small-scale spatial variation in temperate reef algal assemblages has been extensively studied, fine-scale temporal changes have not been well addressed. By sampling the macroalgae of a subtidal reef near Perth (Australia), dominated by the small kelp Ecklonia radiata, every ˜40 days over a 2-year period, we were able to test whether temporal changes in species richness, assemblage structure and species turn-over were related to seasonal changes in surface temperature, solar radiation and wave height. A total of 93 macroalgal taxa were identified, and species richness per sampling time ranged from 25 to 64 taxa 1.25 m -2. Biomass of E. radiata was positively correlated with changes in sea surface temperature and light, and negatively correlated with wave height. Species richness, assemblage structure and turn-over of other macroalgae were more associated with seasonal changes in kelp biomass than environmental variables per se. We conclude that seasonal changes in environmental conditions drive changes in the kelp canopy, which in turn drive changes in species richness and assemblage structure. This suggests that habitat-formers such as kelps can exert a strong temporal influence on associated communities, analogous to well-described spatial influences. Thus, as kelp canopy biomass expands and retracts over time-scales of weeks to months, so does available space for colonization and growth, resulting in a high species turn-over. Species richness is therefore increased and maintained through time, in the same way as canopy-gap mosaics increase and maintain species richness across spatial landscapes.

  20. The potential influence of subduction zone polarity on overriding plate deformation, trench migration and slab dip angle

    NARCIS (Netherlands)

    Schellart, W. P.

    2007-01-01

    A geodynamic model exists, the westward lithospheric drift model, in which the variety of overriding plate deformation, trench migration and slab dip angles is explained by the polarity of subduction zones. The model predicts overriding plate extension, a fixed trench and a steep slab dip for

  1. INVESTIGATION BY NUMERICAL MODELING OF INFLUENCE OF THE SHAPE OF DEFORMING ZONE OF DIE AT WIRE DRAWING OF STEEL HIGH-CARBON WIRE ON TEMPERATURE AND MODE OF DEFORMATION IN WIRE AND DIE

    Directory of Open Access Journals (Sweden)

    Ju. L. Bobarikin

    2010-01-01

    Full Text Available Investigation by numerical modeling of influence of the form of deforming zone of die at drawing of steel highcarbon wire on temperature and strained-deformed state in wire and die is carried out.

  2. A regional tidal/subtidal circulation model of the southeastern Bering Sea: development, sensitivity analyses and hindcasting

    Science.gov (United States)

    Hermann, Albert J.; Stabeno, Phyllis J.; Haidvogel, Dale B.; Musgrave, David L.

    2002-12-01

    A regional eddy-resolving primitive equation circulation model was used to simulate circulation on the southeastern Bering Sea (SEBS) shelf and basin. This model resolves the dominant observed mean currents, eddies and meanders in the region, and simultaneously includes both tidal and subtidal dynamics. Circulation, temperature, and salinity fields for years 1995 and 1997 were hindcast, using daily wind and buoyancy flux estimates, and tidal forcing derived from a global model. This paper describes the development of the regional model, a comparison of model results with available Eulerian and Lagrangian data, a comparison of results between the two hindcast years, and a sensitivity analysis. Based on these hindcasts and sensitivity analyses, we suggest the following: (1) The Bering Slope Current is a primary source of large ( ˜100 km diameter) eddies in the SEBS basin. Smaller meanders are also formed along the 100 m isobath on the southeastern shelf, and along the 200-m isobath near the shelf break. (2) There is substantial interannual variability in the statistics of eddies within the basin, driven by variability in the strength of the ANSC. (3) The mean flow on the shelf is not strongly sensitive to changes in the imposed strength of the ANSC; rather, it is strongly sensitive to the local wind forcing. (4) Vertical mixing in the SEBS is strongly affected by both tidal and subtidal dynamics. Strongest mixing in the SEBS may in fact occur between the 100- and 400-m isobaths, near the Pribilof Islands, and in Unimak Pass.

  3. Spatial and temporal patterns of benthic invertebrates in the Tagus estuary, Portugal: comparison between subtidal and an intertidal mudflat

    Directory of Open Access Journals (Sweden)

    Susana França

    2009-06-01

    Full Text Available Intertidal mudflats are a dominant feature in many estuarine systems and may be a significant component of the feeding grounds available for many fish and bird species. Therefore, it is crucial to determine the importance and role that this particular habitat plays for the different estuarine communities. Spatial and temporal dynamics of macrobenthic communities in an intertidal mudflat of the Tagus estuary were assessed in order to determine the role of this habitat in the whole estuarine functioning. Benthic macroinvertebrate communities were sampled monthly in two intertidal areas (upper and lower and in the adjoining subtidal area for one year. Macroinvertebrate density and biomass in the intertidal mudflat were higher than in the subtidal area, but no clear trends were found between the lower and upper intertidal area. Spatial patterns in the community were more pronounced than seasonal patterns. This benthic community was characterised by high densities of Pygospio elegans, Scrobicularia plana, Cyathura carinata, Hydrobia ulvae and Nereis diversicolor. Abundance and biomass values in this intertidal mudflat were considered low in comparison with other estuarine habitats, namely seagrass beds. Nevertheless, this habitat plays an important role for the main species present in the community, acting as a key area for recruitment, with high concentrations for many invertebrate species.

  4. Safety Zones

    Science.gov (United States)

    These are established primarily to reduce the accidental spread of hazardous substances by workers or equipment from contaminated areas to clean areas. They include the exclusion (hot) zone, contamination reduction (warm) zone, and support (cold) zone.

  5. The influence of the Al stabilizer layer thickness on the normal zone propagation velocity in high current superconductors

    CERN Document Server

    Shilon, I.; Langeslag, S.A.E.; Martins, L.P.; ten Kate, H.H.J.

    2015-06-19

    The stability of high-current superconductors is challenging in the design of superconducting magnets. When the stability requirements are fulfilled, the protection against a quench must still be considered. A main factor in the design of quench protection systems is the resistance growth rate in the magnet following a quench. The usual method for determining the resistance growth in impregnated coils is to calculate the longitudinal velocity with which the normal zone propagates in the conductor along the coil windings. Here, we present a 2D numerical model for predicting the normal zone propagation velocity in Al stabilized Rutherford NbTi cables with large cross section. By solving two coupled differential equations under adiabatic conditions, the model takes into account the thermal diffusion and the current redistribution process following a quench. Both the temperature and magnetic field dependencies of the superconductor and the metal cladding materials properties are included. Unlike common normal zon...

  6. Theoretical study of influence of belt tension of intermediate belt conveyor drive on value of zone of relative slip of traction and carrying belts

    Science.gov (United States)

    Goncharov, K. A.; Grishin, A. V.

    2017-10-01

    The issue of the influence of tension of the traction belt of intermediate drive of the multi-drive belt conveyor on the value of zones of relative rest and sliding of the traction and carrying belts is considered. A variety of values of proportional band of tractive effort regulation of the intermediate drive of belt conveyor while it is being controlled by the tensioning device was obtained in percentage terms. Recommendations on the control of the intermediate drive of belt conveyor by means of the tensioning device when starting and productivity changes are provided.

  7. The influence of manual metal arc multiple repair welding of long operated waterwall on the structure and hardness of the heat affected zone of welded joints

    Directory of Open Access Journals (Sweden)

    Pikuła J.

    2017-03-01

    Full Text Available Welded installations failures of power plants, which are often result from a high degree of wear, requires suitable repairs. In the case of cracks formed in the weld bead of waterwall, weld bead is removed and new welded joint is prepared. However, it is associated with consecutive thermal cycles, which affect properties of heat affected zone of welded joint. This study presents the influence of multiple manual metal arc welding associated with repair activities of long operated waterwall of boiler steel on properties of repair welded joints. The work contains the results of macro and microscopic metallographic examination as well as the results of hardness measurements.

  8. Influence of colloids on the attenuation and transport of phosphorus in alluvial gravel aquifer and vadose zone media.

    Science.gov (United States)

    Pang, Liping; Lafogler, Mark; Knorr, Bastian; McGill, Erin; Saunders, Darren; Baumann, Thomas; Abraham, Phillip; Close, Murray

    2016-04-15

    Phosphorous (P) leaching (e.g., from effluents, fertilizers) and transport in highly permeable subsurface media can be an important pathway that contributes to eutrophication of receiving surface waters as groundwater recharges the base-flow of surface waters. Here we investigated attenuation and transport of orthophosphate-P in gravel aquifer and vadose zone media in the presence and absence of model colloids (Escherichia coli, kaolinite, goethite). Experiments were conducted using repacked aquifer media in a large column (2m long, 0.19m in diameter) and intact cores (0.4m long, 0.24m in diameter) of vadose zone media under typical field flow rates. In the absence of the model colloids, P was readily traveled through the aquifer media with little attenuation (up to 100% recovery) and retardation, and P adsorption was highly reversible. Conversely, addition of the model colloids generally resulted in reduced P concentration and mass recovery (down to 28% recovery), and increased retardation and adsorption irreversibility in both aquifer and vadose zone media. The degree of colloid-assisted P attenuation was most significant in the presence of fine material and Fe-containing colloids at low flow rate but was least significant in the presence of coarse gravels and E. coli at high flow rate. Based on the experimental results, setback distances of 49-53m were estimated to allow a reduction of P concentrations in groundwater to acceptable levels in the receiving water. These estimates were consistent with field observations in the same aquifer media. Colloid-assisted P attenuation can be utilized to develop mitigation strategies to better manage effluent applications in gravelly soils. To efficiently retain P within soil matrix and reduce P leaching to groundwater, it is recommended to select soils that are rich in iron oxides, to periodically disturb soil preferential flow paths by tillage, and to apply a low irrigation rate. Copyright © 2016 Elsevier B.V. All rights

  9. Influence of Control Valve Delay and Dead Zone on the Stability of a Simple Hydraulic Positioning System

    Directory of Open Access Journals (Sweden)

    Bálint Magyar

    2010-01-01

    Full Text Available This paper deals with the PI control of a highly simplified dynamic model of a hydraulic cylinder. It is assumed that the hydraulic fluid is incompressible and that the pump provides constant flow rates, which results in the possibility of velocity control. Two types of anomalies are taken into account: (a the time delay due to the controller computations and the internal pressure dynamics and (b the dead zone of the controller valve. This results in a nonlinear system are described by a piecewise linear discontinuous map. Nonlinear behavior of the system is explored and the practically globally stable parameter domains are identified.

  10. Simulation of Thermopower Influence on Fuel Core of Power Rod in Nuclear Power Plant (NPP Active Zone

    Directory of Open Access Journals (Sweden)

    I. S. Kulikov

    2010-01-01

    Full Text Available The paper considers problems of modern methods for  calculation of designs and materials of nuclear power. A model of numerical analysis for stress-strain state of fuel pins in the NPP active zone is proposed in the paper. The paper contains simulation concerning a fuel core section of a nuclear reactor heat-generating element with subsequent solution of a temperature and thermoelastic problem in computer program complex FEA ANSYS Workbench 11.0. All the obtained results have passed through checking procedure.

  11. Identification of mould influence on columnar-to-equiaxial-transition zone position in Al-Si alloys castings

    Directory of Open Access Journals (Sweden)

    Z. Ignaszak

    2008-08-01

    Full Text Available The course of process validation of CAFE-Calcosoft (ESI-Group models was presented. It was shown the short description of Cellular Automaton Finite Element (CAFE-3D method which was applied to system to solidification process identification and to predict the structure of chosen Al-Si alloy. It was determined the sensitivity of thermal model and model to forecast the microstructure on the variabiity of particular parameters applied to the models taking into consideration the columnar-to-equiaxed transition (CET zone. The cylindrical casts which solidified in homogenous silica (quartz-Q sand mould (A and also in high insulation (HI mould with chill (B which coerces high axial temperature gradient, was investigated. The experiment gave the basis to the validation test of CAFE model considering the CET zone which was preceded by two corresponding cases of solidification in respect to thermal conditions of cast-mould system. The virtual structures of studied casts were compared with real structures. It was shown the satisfactory agreement of both structures.

  12. Influence Of Multimodality Soil On Their Hydrodynamic Behavior Case Of Soils Of The Unsaturated Zone Of Allada Plateau

    Directory of Open Access Journals (Sweden)

    Soclo W. P.

    2015-08-01

    Full Text Available Summary The derivative function f of the cumulative particle-size distribution curve of certain soils has two 02 local maxima two modes in weight percentage for the particle-size ranges of sand and clay one in the range of clays and the other in the range of sands. Are referred to as bimodal soils soils with a particle-size distribution function F having two 02 inflection points the first in the range of clays and the second in the range of sands. Such soils are already part of multiporous soils that have multimodal behavior. Haverkamp and Reggiani 2002 have established for soils whose particle-size have a monomodal behavior a shape similarity between the cumulative particle-size distribution curve and the water retention curve h amp952. A soil whose particle-size distribution has two modes bimodal distribution of soil particle-size usually poses enormous difficulties to soil physicists. Indeed this character when already achieves two in soil bimodal soils results in nine 09 unknown for the same water retention curve model with mathematical-physical basic making it very difficult if not impossible to determine hydrodynamic parameters. So monomadal soils facilitate the study of water transfers in the soil. The hydrodynamic models are available for these types of soils and involve more than 4 unknowns. And with the initial and boundary conditions they allow the indeterminations up without difficulty. Now the work of Tomasella and Hodnett 1998 2000 2002 appears to link the modal character of the soil to climate zones to which they belong. They have come to say that the monomodal soils are specific to temperate regions and bimodal soils are specific to tropical or subtropical regions. The objective of the study is to test the hypothesis of bimodality for the case of soils of the unsaturated zone of Allada plateau located in the intertropical zone and to confirm the applicability of Brooks and Corey 1964 and van Genuchten 1980 models considered in

  13. Impacts of the 2011 tsunami on the subtidal polychaete assemblage and the following recolonization in Onagawa Bay, northeastern Japan.

    Science.gov (United States)

    Abe, Hirokazu; Kobayashi, Genki; Sato-Okoshi, Waka

    2015-12-01

    The ecological impacts of the 2011 Great East Japan Earthquake and tsunami and the following recolonization of the subtidal benthic polychaete community were examined by monthly pre- and post-quake field surveys that were conducted in Onagawa Bay from 2007 to 2013. Before the tsunami, the species composition in this benthic community was constant and was dominated by cirratulid and magelonid polychaetes. The density and biomass of benthic polychaetes drastically decreased after the tsunami, and the polychaete community fluctuated during the 2 years after the natural disaster. Spionid and capitellid polychaetes were dominant at this period. In June 2013, the community entered a new constant stage dominated by maldanids, which is different from the pre-quake community. Ecological impacts due to chemical pollution were suggested in addition to the tsunami disturbance. These overlapping effects and physical, chemical and biological factors affected the recovery and recolonization of the polychaete community after the natural disaster. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Relationships between spatio-temporal environmental and genetic variation reveal an important influence of exogenous selection in a pupfish hybrid zone.

    Science.gov (United States)

    Carson, Evan W; Tobler, Michael; Minckley, W L; Ainsworth, Ryan J; Dowling, Thomas E

    2012-03-01

    The importance of exogenous selection in a natural hybrid zone between the pupfishes Cyprinodon atrorus and Cyprinodon bifasciatus was tested via spatio-temporal analyses of environmental and genetic change over winter, spring and summer for three consecutive years. A critical influence of exogenous selection on hybrid zone regulation was demonstrated by a significant relationship between environmental (salinity and temperature) and genetic (three diagnostic nuDNA loci) variation over space and time (seasons) in the Rio Churince system, Cuatro Ciénegas, Mexico. At sites environmentally more similar to parental habitats, the genetic composition of hybrids was stable and similar to the resident parental species, whereas complex admixtures of parental and hybrid genotypic classes characterized intermediate environments, as did the greatest change in allelic and genotypic frequencies across seasons. Within hybrids across the entire Rio Churince system, seasonal changes in allelic and genotypic frequencies were consistent with results from previous reciprocal transplant experiments, which showed C. bifasciatus to suffer high mortality (75%) when exposed to the habitat of C. atrorus in winter (extreme temperature lows and variability) and summer (abrupt salinity change and extreme temperature highs and variability). Although unconfirmed, the distributional limits of C. atrorus and C. atrorus-like hybrids appear to be governed by similar constraints (predation or competition). The argument favouring evolutionary significance of hybridization in animals is bolstered by the results of this study, which links the importance of exogenous selection in a contemporary hybrid zone between C. atrorus and C. bifasciatus to previous demonstration of the long-term evolutionary significance of environmental variation and introgression on the phenotypic diversification Cuatro Ciénegas Cyprinodon. © 2012 Blackwell Publishing Ltd.

  15. Factors influencing smallholder farmers' behavioural intention towards adaptation to climate change in transitional climatic zones: A case study of Hwedza District in Zimbabwe.

    Science.gov (United States)

    Zamasiya, Byron; Nyikahadzoi, Kefasi; Mukamuri, Billy Billiard

    2017-08-01

    This paper examines factors influencing behavioural change among smallholder farmers towards adaptation to climate change in transitional climatic zones of Africa, specifically, Hwedza District in Zimbabwe. Data for this study were collected from 400 randomly-selected smallholder farmers, using a structured questionnaire, focus group discussions and key informant interviews. The study used an ordered logit model to examine the factors that influence smallholder farmers' behavioural intention towards adaptation to climate change. Results from the study show that the gender of the household head, access to extension services on crop and livestock production, access to climate information, membership to social groups and experiencing a drought have a positive influence on farmers' attitude towards adaptation to climate change and variability. The study concluded that although the majority of smallholder farmers perceive that the climate is changing, they continue to habour negative attitudes towards prescribed climate change adaptation techniques. This study recommends more education on climate change, as well as adaptation strategies for both agricultural extension workers and farmers. This can be complemented by disseminating timely climate information through extension officers and farmers' groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Influence of two different geo-climatic zones on the prevalence and time trends of asthma symptoms among Spanish adolescents and schoolchildren

    Science.gov (United States)

    García-Marcos, Luis; Batllés-Garrido, José; Blanco-Quirós, Alfredo; García-Hernández, Gloria; Guillén-Grima, Francisco; González-Díaz, Carlos; García-Merino, Águeda; Arnedo-Pena, Alberto; Busquets-Monge, Rosa M.; Morales-Suárez-Varela, María; López-Silvarrey-Varela, Ángel; García-Andoin, Nekane

    2009-01-01

    Few studies have focused on the long-term influence of the climate on the prevalence of asthma. The aim of this study is to establish the influence of geo-climatic conditions on the prevalence of asthma symptoms both in adolescents and schoolchildren, and to discover if this influence is associated with their time trends. Eight centres in Spain performed both ISAAC phases I (1994) and III (2002) in children 13-14 years old. Six of them also surveyed children 6-7 years old. For each age group and phase, about 3,000 children were surveyed per centre. This study examines the prevalence of current wheeze and severe current wheeze in two different geo-climatic zones, coast and plateau, considering their relative humidity and temperature range. In both age groups, the mean asthma prevalence on the coast, for phase I and III, was significantly higher than on the plateau. Living on the plateau was an independent protective factor for current wheeze and severe current wheeze for the two age groups. Within the coastal centres, the increase of the annual relative humidity was a statistical significant risk factor for current wheeze, the same trend existing for current severe wheeze. These effects were independent of the sex and of the phase of the study. The prevalence of asthma and severe asthma symptoms is more frequent on the coast of Spain as compared to the inner plateau. This finding was repeated both in 1994 and in 2002.

  17. The Influence of Orbital Resonances on the Water Transport to Objects in the Circumprimary Habitable Zone of Binary Star Systems

    Science.gov (United States)

    Bancelin, David; Pilat-Lohinger, Elke; Maindl, Thomas I.; Ragossnig, Florian; Schäfer, Christoph

    2017-06-01

    We investigate the role of secular and mean motion resonances on the water transport from a belt of icy asteroids onto planets or embryos orbiting inside the circumprimary habitable zone (HZ) of a binary star system. In addition, the host-star has an accompanying gas giant planet. For a comparison, we perform two case studies where a secular resonance (SR) is located either inside the HZ close to 1.0 au (causing eccentric motion of a planet or embryos therein) or in the asteroid belt, beyond the snow line. In the latter case, a higher flux of icy objects moving toward the HZ is expected. Collisions between asteroids and objects in the HZ are treated analytically. Our purely dynamical study shows that the SR in the HZ boosts the water transport however, collisions can occur at very high impact speeds. In this paper, we treat for the first time, realistic collisions using a GPU 3D-SPH code to assess the water loss in the projectile. Including the water loss into the dynamical results, we get more realistic values for the water mass fraction of the asteroid during an impact. We highlight that collisions occurring at high velocities greatly reduce the water content of the projectile and thus the amount of water transported to planets or embryos orbiting inside the HZ. Moreover, we discuss other effects that could modify our results, namely the asteroid’s surface rate recession due to ice sublimation and the atmospheric drag contribution on the asteroids’ mass loss.

  18. Influence of Column Axial Load and Heat Affected Zone on the Strength of Aluminium Column Web in Tension

    Directory of Open Access Journals (Sweden)

    Gianfranco De Matteis

    2014-05-01

    Full Text Available The component method for aluminium joints has been recently introduced in some codes and guidelines. Nevertheless, it is still in need of some development and improvement, as in some cases it was obtained by adapting the existing formulations that are valid for steel. The current paper presents the main outcomes of a parametric analysis carried out by means of finite element (FE numerical models for determining the influence of both column axial load and heat affected zone—in the case of welded details—on the structural response of the column web in a tension component. The proposed study integrates previous research carried out by the authors, where the influence of the assumed alloy was investigated and interpreted by corrective parameters expressed as a function of both the material strain hardening and ductility.

  19. Influence of growth regulator on plant growth, development and yield formation of sunflower hybrids (F1 under the conditions of Southern Steppe zone of Ukraine

    Directory of Open Access Journals (Sweden)

    О. А. Єременко

    2017-06-01

    Full Text Available Purpose. To study the effect of AKM plant growth regulator on growth, development and yield formation of sunflower (Helianthus annuus L. hybrids in hybridization plots under the conditions of the Southern Steppe zone of Ukraine. Methods. Laboratory tests, field study, statistical evaluation. Results. The results of studies devoted to determining the optimal AKM concentration for the treatment of seeds of the maternal and paternal lines, the effect of AKM on field germination, biometric parameters of sunflower plants, seed quality (F1 and yield are presented. Three hybrids of the Ukrainian selection, such as ‘Alpha’, ‘Logos’ and ‘Persei’ were studied during 2014–2016. Optimal concentration of AKM (0.0015 g/l was defined. The vigor of seeds processed by AKM was higher than in check variety by 0.8–12.8 р.р. (♂; 0.4–10.7 p.p. (♀, laboratory germination – by 2.3–6.1 p.p. (♂; 3.5–6.2 p.p. (♀. In 2016, the sunflower plant height for all variants exceeded this parameter to be obtained for other years of the study. This could be explained by the fact that HTC in 2016 for the BBCH 00–39 period was 1.4 times higher than in 2015. In general, hybrids as the studied factor considerably influenced sunflower yield, and the share of the hybrid (factor A influence is 33%. This should be considered when selecting hybrids for sunflower cultivation technologies in the Steppe zone of Ukraine. Conclusions. Hydrothermal conditions of the year had the maximum impact on the formation of seed quality and yield of sunflower plants of the hybrids under study, but when using AKM growth regulator for presowing seed treatment, this negative impact was reduced by an average of 23%.

  20. Selectivity of subtidal benthic invertebrate communities for local microalgal production in an estuarine mangrove ecosystem during the post-monsoon period

    Science.gov (United States)

    Bouillon, S.; Koedam, N.; Baeyens, W.; Satyanarayana, B.; Dehairs, F.

    2004-03-01

    Stable isotope analysis was used as a tool to assess the main carbon sources sustaining the benthic invertebrate communities in an estuarine mangrove ecosystem along the southeast coast of India during the post-monsoon season. In particular, we wanted to test whether the large amounts of terrestrial carbon brought in during the monsoon influence the benthic foodweb in this area, by comparing with earlier data on the pre-monsoon period. The δ 13C of the dissolved inorganic carbon (DIC) pool was spatially variable, with lower values in the mangrove creeks (-10.6 to -8.9‰) compared to those in the adjacent bay region (-4.3 to -2.6‰). Fixation of the 13C-depleted DIC in the mangrove creeks should therefore result in a partial overlap in the δ 13C signature of mangrove-derived carbon and local phytoplankton. The lack of correlation between δ 13C values of benthic invertebrates (which showed a large spatial gradient of ˜8‰) and those of sediments or suspended matter (both showing only small spatial gradient of food sources. These results are similar to those obtained during the pre-monsoon period in the same area, although in each region δ 13C values were consistently more negative (by 1-3‰) during the post-monsoon period, consistent with the seasonality in δ 13C DIC. By defining selectivity as the relative spatial gradient in consumer δ 13C compared to the δ 13C of bulk particulate organic carbon (POC) and δ 13C DIC (as a proxy for the variations expected in local producers), and assuming that the selectivity is similar along the salinity gradient, we estimate that benthic invertebrates rely almost entirely on locally produced microalgal carbon sources. A critical evaluation of earlier studies shows that there is currently no unambiguous evidence for a trophic role of mangrove litter in sustaining subtidal benthic and pelagic invertebrate communities in adjacent aquatic systems.

  1. Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover

    Directory of Open Access Journals (Sweden)

    J. A. Leach

    2014-02-01

    Full Text Available Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1 winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2 stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground events, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms vertical energy exchanges (net radiation, sensible and latent heat fluxes, bed heat conduction, and stream friction and hyporheic energy fluxes during rain and rain-on-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that

  2. Influence of management of variables, sampling zones and land units on LR analysis for landslide spatial prevision

    Directory of Open Access Journals (Sweden)

    R. Greco

    2013-09-01

    Full Text Available Several authors, according to different methodological approaches, have employed logistic Regression (LR, a multivariate statistical analysis adopted to assess the spatial probability of landslide, even though its fundamental principles have remained unaltered. This study aims at assessing the influence of some of these methodological approaches on the performance of LR, through a series of sensitivity analyses developed over a test area of about 300 km2 in Calabria (southern Italy. In particular, four types of sampling (1 – the whole study area; 2 – transects running parallel to the general slope direction of the study area with a total surface of about 1/3 of the whole study area; 3 – buffers surrounding the phenomena with a 1/1 ratio between the stable and the unstable area; 4 – buffers surrounding the phenomena with a 1/2 ratio between the stable and the unstable area, two variable coding modes (1 – grouped variables; 2 – binary variables, and two types of elementary land (1 – cells units; 2 – slope units units have been tested. The obtained results must be considered as statistically relevant in all cases (Aroc values > 70%, thus confirming the soundness of the LR analysis which maintains high predictive capacities notwithstanding the features of input data. As for the area under investigation, the best performing methodological choices are the following: (i transects produced the best results (0 P(y ≤ 93.4%; Aroc = 79.5%; (ii as for sampling modalities, binary variables (0 P(y ≤ 98.3%; Aroc = 80.7% provide better performance than ordinated variables; (iii as for the choice of elementary land units, slope units (0 P(y ≤ 100%; Aroc = 84.2% have obtained better results than cells matrix.

  3. Influence of management of variables, sampling zones and land units on LR analysis for landslide spatial prevision

    Science.gov (United States)

    Greco, R.; Sorriso-Valvo, M.

    2013-09-01

    Several authors, according to different methodological approaches, have employed logistic Regression (LR), a multivariate statistical analysis adopted to assess the spatial probability of landslide, even though its fundamental principles have remained unaltered. This study aims at assessing the influence of some of these methodological approaches on the performance of LR, through a series of sensitivity analyses developed over a test area of about 300 km2 in Calabria (southern Italy). In particular, four types of sampling (1 - the whole study area; 2 - transects running parallel to the general slope direction of the study area with a total surface of about 1/3 of the whole study area; 3 - buffers surrounding the phenomena with a 1/1 ratio between the stable and the unstable area; 4 - buffers surrounding the phenomena with a 1/2 ratio between the stable and the unstable area), two variable coding modes (1 - grouped variables; 2 - binary variables), and two types of elementary land (1 - cells units; 2 - slope units) units have been tested. The obtained results must be considered as statistically relevant in all cases (Aroc values > 70%), thus confirming the soundness of the LR analysis which maintains high predictive capacities notwithstanding the features of input data. As for the area under investigation, the best performing methodological choices are the following: (i) transects produced the best results (0 < P(y) ≤ 93.4%; Aroc = 79.5%); (ii) as for sampling modalities, binary variables (0 < P(y) ≤ 98.3%; Aroc = 80.7%) provide better performance than ordinated variables; (iii) as for the choice of elementary land units, slope units (0 < P(y) ≤ 100%; Aroc = 84.2%) have obtained better results than cells matrix.

  4. Influence of litter thickness on the structure of litter macrofauna of deciduous forests of Ukraine’s steppe zone

    Directory of Open Access Journals (Sweden)

    V. V. Brygadyrenko

    2016-02-01

    Full Text Available The litter in a forest ecosystem acts as a trophic substrate, and at the same time it is the environment for litter invertebrates. But despite this fact, there has been very little research conducted on the influence of litter thickness on the structure of litter macrofauna. The litter of steppe forests contains most types of integrated communities of forest ecosystems. This means that its thickness cannot avoid playing a significant role in the functioning of the ecosystem. Following to the standard methodologies, Invertebrates were collected using pit-fall traps in deciduous forests of Nikolaev, Zaporizhzhya, Dnipropetrovsk, Donetsk and Kharkiv oblasts, which are characterized by different types of geomorphological profile, different moisture conditions, soil salinity, tree crown and herbaceous vegetation density, soil texture and other factors. The total number of macrofauna increases in conditions where litter thickness exceeds40 mmin comparison with forest ecosystems with fragmented and average capacity litter. The number of litter macrofauna species also increases from 11–23 to 38 species on average when litter thickness increases to more than40 mm. The Shannon and Pielou diversity indexes show no definite tendencies to change in relation to changing degrees of litter thickness. At sites of greater thickness of the litter layer, the corresponding increase in the absolute number of litter mesofauna invertebrates is mostly due to saprophages, and the increase the number of species – due to zoophages. The optimum structure of domination was observed at sites with maximum thickness of litter. The proportion of large species shows no statistically significant change in relation to variations in litter thickness. The qualitative compound of the fauna at sites with thick litter changes mainly due to an increase in the number of Carabidae species.

  5. Composition and distribution of subtidal and intertidal crustacean assemblages in soft-bottoms of the Ria de Vigo (NW Spain

    Directory of Open Access Journals (Sweden)

    Eva Cacabelos

    2010-08-01

    Full Text Available The intertidal and subtidal soft-bottoms of the inner area of the Ria de Vigo (NW Spain were sampled in November and December 1999, and spatial distribution of crustacean species was examined. Environmental variables from water and sediment were measured at each sampling site. Amphipods and myocopids were the numerically dominant orders (49.9 and 26.9% dominance, amphipods accounting for more than 54% of identified taxa. The highest crustacean densities occurred with 55-41 species and 5953.6-4346.4 ind. m–2 in external areas, where the diversity index reached the maximum values. Multivariate techniques revealed that distribution of crustaceans in the inlet was highly dependent on depth. Ordination analysis determined three major assemblages: Intertidal bottoms colonized by seagrasses and subjected to strong variations of salinity were dominated by the amphipod Melita palmata, harpacticoids and the isopod Idotea baltica (Group A. The amphipod Corophium cf. runcicorne and the cumacean Iphinoe tenella predominated in the muddy bottoms of central areas (Group B. These species were also present in the deep muddy bottoms of the mouth of the inlet, with high carbonate and gravel contents, and with the myocopids and the amphipod Microdeutopus cf. armatus displaying maximum dominances (Group C.

  6. The effect of the Jessica grounding on subtidal invertebrate and plant communities at the Galápagos wreck site.

    Science.gov (United States)

    Marshall, Paul A; Edgar, Graham J

    2003-01-01

    Impacts of the grounding of the oil tanker Jessica off San Cristóbal island, Galápagos, included both effects of oil on biota and also mechanical effects associated with a shallow furrow 50 m x 30 m gouged across the rocky seafloor and wreckage strewn over 7500 m(2). The wreckage represented a minor but potentially chronic source of pollution to the surrounding environment through delayed releases of oil, antifouling compounds and other toxic chemicals, and a possible source of exotic marine taxa. Investigation at the wreck site indicated that impacts on subtidal plant and macro-invertebrate communities were largely confined within 100 m of the wreck site itself. Observed population effects included significant increases in cover of opportunistic algae (filamentous green algae, filamentous red algae and Ulva sp.) and the hydroid Ectopleura media adjacent to the wreck, while densities of the green sea urchin Lytechinus semituberculatus significantly decreased from 0.3 m(-2) adjacent to the wreck to 11 m(-2) at 100 m distance.

  7. On the influence of waves on air-sea CO2 gas transfer in the coastal zone

    Science.gov (United States)

    Ocampo-Torres, Francisco Javier; Gutiérrez-Loza, Lucía

    2017-04-01

    As part of the "Sea Surface Roughness as Air-Sea Interaction Control" project, we study the influence of wave-associated processes controlling turbulent CO2 fluxes through the air-sea interface in a coastal region, at the Northwest of Baja California, México. The conducted field campaign allowed us with a full year dataset (May 2014-April 2015) of high quality data of CO2 fluxes (FCO2) estimated through Eddy Covariance (EC). Ocean surface waves were also recorded using an Acoustic Doppler Current Profiler (Workhorse Sentinel, Teledyne RD Instruments) located at 10 m depth about 350 m away from the shore were the EC tower was located. The study area was found to be a sink of CO2 under moderate wind and wave conditions with a mean flux of -1.32 μmol/m2s [1]. The linear correlation between the wind speed and FCO2 was found rather weak, suggesting that other physical processes besides wind may also be important for the gas exchange modulation at coastal waters at these temporal scales. Recent results on the other hand, through quantile regression analysis computed between FCO2 and a) wind speed, b) significant wave height, c) wave steepness and d) water temperature, allowed us to identify the significant wave height as the best correlated variable. However, the correlation varied with the probability distribution characteristics of FCO2, with the regression slope presenting both positive and negative values. The latter implies that in the coastal areas, the presence of swell is the key factor that promotes the intensification of the fluxes into and from the ocean. In fact, making use of the water temperature as indicator of the CO2 concentration in the water phase, the behavior of the relationship between the FCO2 and the significant wave height might be partially explained. Further analysis showed that the characteristics of wind speed and water temperature determine the direction in which the FCO2 occur. This work is a contribution from RugDiSMar project (CONACYT

  8. Influences of the Tonga Subduction Zone on seafloor massive sulfide deposits along the Eastern Lau Spreading Center and Valu Fa Ridge

    Science.gov (United States)

    Evans, Guy N.; Tivey, Margaret K.; Seewald, Jeffrey S.; Wheat, C. Geoff

    2017-10-01

    This study investigates the morphology, mineralogy, and geochemistry of seafloor massive sulfide (SMS) deposits from six back-arc hydrothermal vent fields along the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) in the context of endmember vent fluid chemistry and proximity to the Tonga Subduction Zone. To complement deposit geochemistry, vent fluid analyses of Cu, Zn, Ba, Pb and H2,(aq) were completed to supplement existing data and enable thermodynamic calculations of mineral saturation states at in situ conditions. Results document southward increases in the abundance of mantle-incompatible elements in hydrothermal fluids (Ba and Pb) and SMS deposits (Ba, Pb, As, and Sb), which is also expressed in the abundance of barite (BaSO4) and galena (PbS) in SMS deposits. These increases correspond to a decrease in distance between the ELSC/VFR and the Tonga Subduction Zone that correlates with a change in crustal lithology from back-arc basin basalt in the north to mixed andesite, rhyolite, and dacite in the south. Barite influences deposit morphology, contributing to the formation of horizontal flanges and squat terraces. Results are also consistent with a regional-scale lowering of hydrothermal reaction zone temperatures from north to south (except at the southernmost Mariner vent field) that leads to lower-temperature, higher-pH vent fluids relative to mid-ocean ridges of similar spreading rates (Mottl et al., 2011). These fluids are Cu- and Zn-poor and the deposits formed from these fluids are Cu-poor but Zn-rich. In contrast, at the Mariner vent field, higher-temperature and lower pH vent fluids are hypothesized to result from higher reaction zone temperatures and the localized addition of acidic magmatic volatiles (Mottl et al., 2011). The Mariner fluids are Cu- and Zn-rich and vent from SMS deposits that are rich in Cu but poor in Zn with moderate amounts of Pb. Thermodynamic calculations indicate that the contrasting metal contents of vent fluids

  9. Factorial Analysis of Welding Current Influence on Heat Affected Zone Hardness of Cast Iron, Aluminium, and Mild Steel Weldments Cooled in Palm Oil

    Directory of Open Access Journals (Sweden)

    C. I. Nwoye

    2013-01-01

    Full Text Available Factorial analysis of heat affected zone hardness of some metals was evaluated. Three models were derived and used as tools for evaluating the welding current influence on the predictability of HAZ hardness in aluminium, cast iron, and mild steel weldments similarly cooled in palm oil. It was discovered that on welding these materials, and similarly cooling their respective weldments in palm oil, the model predicts aluminium weldment HAZ hardness by multiplying the determined general current product rule (GCPR with the ratio: HAZ hardness product of cast iron and mild steel/HAZ hardness sum of cast iron and mild steel . Computational analysis of experimental and model-predicted results indicates that aluminium, cast iron, and mild steel weldment HAZ hardness per unit welding current as evaluated from experiment and derived model are 3.3917, 4.8333, and 2.7944 and 3.3915, 4.8335, and 2.7946 (VHN A−1, respectively. Deviational analysis shows that the maximum deviation of model-predicted HAZ hardness from the experimental results is less than 0.007%. This invariably implies over 99.99 % confidence level for the derived models.

  10. Environmental Risks of Landscape Botanical Complexes and Minimization of Technogenic Influence Exerted by Objects of Oil&Gas Production in Steppe Zone of the Southern Urals

    Science.gov (United States)

    Ryabukhina, M. V.; Maiski, R. A.; Salikhova, R. H.

    2017-11-01

    The modern rates of oil and gas production, developed industry, high technologies in the field of the construction and operation of wells, pipelines and other facilities of the oil and gas industry, as well as growing environmental control do not fully solve the problem of the negative impacts on natural objects, in particular, landscape botanical complexes. Taking into account the increasing oil and gas production rates, the existing objects-Orenburg NGKM and constructed ones, for example, by 2015 in the Orenburg region was organized a “new thread” oil company, LLC, the activities of which include exploration, design and preparation of the Mogutovskoye deposits, a part of the Vorontsov and a part of Gremjacheskoye deposits, as well as their exploitation, should explore and develop some effective mechanisms to minimize and eliminate the environmental risks of industrial impact. In our view the multi-component continuous monitoring of environmental risks will help to formulate an effective strategy and develop an effective preventive mechanism of technological activities, identify landscape botanical complexes which are more exposed to environmental risks as well as the regional forecast component changes in terms of a landscape botanical complex in the zone of technogenic influence exerted by the objects of the oil and gas industry.

  11. NEARSHORE ZONE

    African Journals Online (AJOL)

    hb"'/ H“ —_'~. Fig. l: Schematic plan showing the incident wave and subsequent breaking in the nearshore zone. The still-water line indicates the mean water level and .... obtained by taking the square of the high frequency velocity components.

  12. Land-to-sea connectivity: linking human-derived terrestrial subsidies to subtidal habitat change on open rocky coasts.

    Science.gov (United States)

    Gorman, Daniel; Russell, Bayden D; Connell, Sean D

    2009-07-01

    Spatial subsidies are considered strong where differences in resource availability between donor and recipient systems are greatest. We tested whether human activities on land can increase subsidies of terrigenous nitrogen to open rocky coasts and whether these differences can predict apparent deforestation of kelp forests. We first identified landscape-scale variation in the human-mediated transfer of dissolved inorganic nitrogen (DIN) from natural, agricultural, and urban catchments to temperate coasts after episodes of rainfall. Compared to natural catchments, subsidies of DIN were on average 8-407 times greater in urban catchments, and 1-63 times greater in agricultural catchments. Urban derived nitrogen was attributed to the release of sewage effluent, as delineated by delta15N isotopic values of transplanted algae. Having made this link, we then assessed whether this catchment-scale variation may account for variation in structure of subtidal habitats, particularly as related to theory of nutrient-driven shifts of habitat from perennial (i.e., canopy-forming algae) to opportunistic species (i.e., turf-forming algae). We not only detected patterns consistent with this theory, but also established that the size and total proportion of patches of turf-forming algae were greater where the ratio of donor: recipient nitrogen loads was greater (i.e., size of subsidy). An important realization was that deforestation may be more strongly related to variation in the size of subsidy rather than size of human populations, particularly among urban catchments. These data directly link the type of human activity within catchments to the modification of land-to-sea subsidies and indirectly support theory that predicts terrestrial inputs to have greater ecological effects where the disparity in resource availability between donor and recipient is exacerbated. Our evidence has been used by coastal managers to reconsider their management of coastal systems and has subsequently

  13. Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior

    Science.gov (United States)

    Witman, Jon D.; Smith, Franz; Novak, Mark

    2017-01-01

    In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species–blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)–drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus). Triggerfish predation effects were strong, causing a 24-fold reduction of pencil urchin densities during the initial 21 hours of a trophic cascade experiment. A trophic cascade was demonstrated for pencil urchins, but not for green urchins, by significantly higher percent cover of urchin-grazed algae in cages that excluded predatory fish than in predator access (fence) treatments. Pencil urchins were more abundant at night when triggerfish were absent, suggesting that this species persists by exploiting a nocturnal predation refuge. Time-series of pencil urchin survivorship further demonstrated per capita interference effects of hogfish and top predators. These interference effects respectively weakened and extended the trophic cascade to a fourth trophic level through behavioral modifications of the triggerfish-urchin interaction. We conclude that interference behaviors capable of modifying interaction strength warrant greater attention as mechanisms for altering top-down control, particularly in speciose food webs. PMID:28430794

  14. Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior.

    Science.gov (United States)

    Witman, Jon D; Smith, Franz; Novak, Mark

    2017-01-01

    In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species-blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)-drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus). Triggerfish predation effects were strong, causing a 24-fold reduction of pencil urchin densities during the initial 21 hours of a trophic cascade experiment. A trophic cascade was demonstrated for pencil urchins, but not for green urchins, by significantly higher percent cover of urchin-grazed algae in cages that excluded predatory fish than in predator access (fence) treatments. Pencil urchins were more abundant at night when triggerfish were absent, suggesting that this species persists by exploiting a nocturnal predation refuge. Time-series of pencil urchin survivorship further demonstrated per capita interference effects of hogfish and top predators. These interference effects respectively weakened and extended the trophic cascade to a fourth trophic level through behavioral modifications of the triggerfish-urchin interaction. We conclude that interference behaviors capable of modifying interaction strength warrant greater attention as mechanisms for altering top-down control, particularly in speciose food webs.

  15. Trophic ecology of Atlantic seabob shrimp Xiphopenaeus kroyeri: Intertidal benthic microalgae support the subtidal food web off Suriname

    Science.gov (United States)

    Willems, Tomas; De Backer, Annelies; Kerkhove, Thomas; Dakriet, Nyasha Nanseerà; De Troch, Marleen; Vincx, Magda; Hostens, Kris

    2016-12-01

    A combination of stomach content analyses and dual stable isotope analyses was used to reveal the trophic ecology of Atlantic seabob shrimp Xiphopenaeus kroyeri off the coast of Suriname. This coastal penaeid shrimp species has a rather omnivorous diet, feeding opportunistically on both animal prey and primary food sources. The species is a predator of hyperbenthic crustaceans, including copepods, amphipods and the luciferid shrimp Lucifer faxoni, which are mainly preyed upon during daytime, when these prey typically reside near the seabed. Benthic microalgae (BM) from intertidal mudflats and offshore sedimentary organic matter (SOM) were important primary food sources. Due to their depleted 13C values, coastal sedimentary and suspended organic matter, and carbon from riverine and mangrove-derived detritus were not incorporated by X. kroyeri. An ontogenetic diet shift was observed from postlavae to juveniles and adults. Adult X. kroyeri were located higher in the food chain, mainly preying on larger benthic organisms. Intertidal BM were an important food source for all life stages of X. kroyeri, contributing up to 64% to the overall diet based on a Bayesian mixing model. Because X. kroyeri is the main epibenthic organism found at high densities in nearshore waters up to 30 m depth, the species plays a crucial role in transferring energy from low trophic level prey and primary food sources up to higher levels in the food chain. Our results indicate that primary production on intertidal mudflats, through BM, forms an important energy source for the subtidal turbid-water food web in muddy tropical coasts. Conservation of intertidal areas and their associated mangrove systems will therefore likely benefit coastal shrimp production and fisheries in tropical ecosystems.

  16. Feeding guild composition of a macrobenthic subtidal community along a depth gradient

    Directory of Open Access Journals (Sweden)

    Marina Dolbeth

    2009-06-01

    Full Text Available The feeding guild composition of a macrobenthic community from southern Portugal was studied along a depth gradient (1.3 to 32 m. This gradient comprised shallow areas with severe physical stress and deeper areas with no significant hydrodynamic impact at the seafloor. The main goal was to determine the influence of the spatial and temporal differences of the hydrodynamic impact at the seafloor on the feeding guild composition of the macrobenthic community. The feeding guild composition changed gradually with depth, which reflects the differences in the hydrodynamics impact at the seafloor. Herbivores and sand-lickers dominated at the shallowest depths with fine sands, which correlated with higher levels of primary production. Scavengers were also distributed in the shallow areas, which was associated with the lower predation impact. Suspension feeders, in accordance with their physiological requirements, were distributed in coarser sands subjected to a physical impact. Carnivores, surface deposit feeders and sub-surface deposit feeders were distributed mainly below 8 m depth, where there was no significant impact from the wave climate. Carnivores were associated with coarser sands and were mainly small polychaetes and nemerteans. Sub-surface and surface deposit feeders were more abundant in the deepest areas of the depth gradient with fine sands and mud deposits with higher organic content. However, surface deposit feeders also occurred at shallower depths. Some seasonal differences related to disturbance impacts were found in the numerical dominance of the feeding guilds.

  17. Species interactions can maintain resistance of subtidal algal habitats to an increasingly modified world

    Directory of Open Access Journals (Sweden)

    Laura J. Falkenberg

    2015-07-01

    Full Text Available Current trends in habitat loss have been forecast to accelerate under anticipated global change, thereby focusing conservation attention on identifying the circumstances under which key species interactions retard habitat loss. Urbanised coastlines are associated with broad-scale loss of kelp canopies and their replacement by less productive mats of algal turf, a trend predicted to accelerate under ocean acidification and warming (i.e. enhanced CO2 and temperature. Here we use kelp forests as a model system to test whether efforts to maintain key species interactions can maintain habitat integrity under forecasted conditions. First, we assessed whether increasing intensity of local human activity is associated with more extensive turf mats and sparser canopies via structured field observations. Second, we experimentally tested the hypothesis that intact canopies can resist turf expansion under enhanced CO2 and temperature in large mesocosms. In the field, there was a greater proportion of turf patches on urbanised coasts of South Australia than in agricultural and urban catchments in which there was a greater proportion of canopy-forming algae. Mesocosm experiments revealed this expansion of turfs is likely to accelerate under increases in CO2 and temperature, but may be limited by the presence of intact canopies. We note that even in the presence of canopy, increases in CO2 and temperature facilitate greater turf covers than occurs under contemporary conditions. The influence of canopy would likely be due to shading of the understorey turfs which, in turn, can modify their photosynthetic activity. These results suggest that resistance of habitat to change under human-dominated conditions may be managed via the retention of key species and their interactions. Management that directly reduces the disturbance of habitat-forming organisms (e.g. harvesting or reverses loss through restoration may, therefore, reinforce habitat resistance in an

  18. Consistent Richness-Biomass Relationship across Environmental Gradients in a Marine Macroalgal-Dominated Subtidal Community on the Western Antarctic Peninsula.

    Directory of Open Access Journals (Sweden)

    Nelson Valdivia

    Full Text Available Biodiversity loss has spurred the biodiversity-ecosystem functioning research over a range of ecosystems. In Antarctica, however, the relationship of taxonomic and functional diversity with ecosystem properties (e.g., community biomass has received less attention, despite the presence of sharp and dynamic environmental stress gradients that might modulate these properties. Here, we investigated whether the richness-biomass relationship in macrobenthic subtidal communities is still apparent after accounting for environmental stress gradients in Fildes Bay, King George Island, Antarctica. Measurements of biomass of mobile and sessile macrobenthic taxa were conducted in the austral summer 2013/4 across two environmental stress gradients: distance from nearest glaciers and subtidal depth (from 5 to 30 m. In general, community biomass increased with distance from glaciers and water depth. However, generalised additive models showed that distance from glaciers and depth accounted for negligible proportions of variation in the number of functional groups (i.e., functional richness and community biomass when compared to taxonomic richness. Functional richness and community biomass were positive and saturating functions of taxonomic richness. Large endemic, canopy-forming brown algae of the order Desmarestiales dominated the community biomass across both gradients. Accordingly, differences in the composition of taxa accounted for a significant and large proportion (51% of variation in community biomass in comparison with functional richness (10%. Our results suggest that the environmental factors here analysed may be less important than biodiversity in shaping mesoscale (several km biomass patterns in this Antarctic system. We suggest that further manipulative, hypothesis-driven research should address the role of biodiversity and species' functional traits in the responses of Antarctic subtidal communities to environmental variation.

  19. Integrated geophysics reveals a steep lithologic boundary and Moho offset at the western Idaho shear zone that strongly influenced later tectonic events

    Science.gov (United States)

    Davenport, K. K.; Ghanekar, S.; Stanciu, A. C.; Bremner, P. M.; Hole, J. A.; Tikoff, B.; Russo, R. M.

    2016-12-01

    Multiple geophysical data sets from the EarthScope Idaho-Oregon (IDOR) project were integrated to examine crustal structure and composition across the boundary between accreted terranes and the Precambrian craton in Idaho and Oregon. New results from controlled-source seismic S-wave data and gravity data are incorporated with previous results from controlled-source seismic P-waves, broadband seismic receiver functions, and broadband ambient noise surface waves. The geophysical data constrain the deeper structure of the western Idaho shear zone (WISZ), imaging a near-vertical, through-going structure that juxtaposes different seismic velocities and densities throughout the crust and offsets the Moho by 7-8 km. Previous work suggested that the WISZ, which formed when transpressional deformation overprinted the original terrane-craton suture, was less steep at depth or was offset within the crust. West of the WISZ, the crust of the Blue Mountains Province oceanic accreted terranes is characterized by faster seismic velocities and higher densities, intermediate lithology with a mafic lower crust, and a shallower, 30 km deep Moho. East of the WISZ the crust of the Precambrian craton and the Idaho batholith has slower seismic velocities, lower densities, felsic lithology with an intermediate-composition lower crust, and a deeper 35-40 km Moho. The juxtaposition of crustal blocks with distinctly contrasting lithologies created a fundamental rheologic boundary that strongly influenced the response of the crust to subsequent tectonic events, including emplacement of the Idaho batholith and the Columbia River basalts, and Basin and Range extension. The strong contrast across the WISZ restricted these tectonic events to primarily one side or the other, and has likely contributed to the survival of this steep vertical boundary and Moho offset through the later tectonic and heating events.

  20. Influence of multi-industrial activities on trace metal contamination: an approach towards surface water body in the vicinity of Dhaka Export Processing Zone (DEPZ).

    Science.gov (United States)

    Ahmed, Golam; Miah, M Arzu; Anawar, Hossain M; Chowdhury, Didarul A; Ahmad, Jasim U

    2012-07-01

    Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic

  1. Investigating the Influence of Auxiliary Rails on Dynamic Behavior of Railway Transition Zone by a 3D Train-Track Interaction Model

    Directory of Open Access Journals (Sweden)

    H. Heydari-Noghabi

    Full Text Available Abstract Abrupt track vertical stiffness variations along railway tracks can lead to increased dynamic loads, asymmetric deformations, damaged track components, and consequently, increased maintenance costs. The junction of slab track and ballasted track is one of the existing areas where vertical track stiffness can suddenly change, therefore requiring a transition zone that smoothes the track stiffness change. One of the methods for constructing the transition zone at the junction of slab and ballasted tracks is to install auxiliary rails along the transition zone. In the present study, the dynamic behavior of this type of transition zone was evaluated by a train-track interaction model. For this purpose, a 3D model of the railway track was made, representing the slab track, the transition zone, and the ballasted track. Then, the modeling results were validated by the results of field tests. Afterwards, in order to study the dynamic behavior of the transition zone with auxiliary rails, different sensitive analyses, such as vehicle speed, vehicle load, number of auxiliary rails and railpad stiffness, were performed with the model. The obtained results showed that the use of auxiliary rails reduced the rail deflection variations along the transition zone from 35% to 28% for low and medium speeds (120, 160, 200 km/h, and from 40% to 33% for high speeds (250, 300 km/h.

  2. Sound Zones

    DEFF Research Database (Denmark)

    Møller, Martin Bo; Olsen, Martin

    2017-01-01

    Sound zones, i.e. spatially confined regions of individual audio content, can be created by appropriate filtering of the desired audio signals reproduced by an array of loudspeakers. The challenge of designing filters for sound zones is twofold: First, the filtered responses should generate...... an acoustic separation between the control regions. Secondly, the pre- and post-ringing as well as spectral deterioration introduced by the filters should be minimized. The tradeoff between acoustic separation and filter ringing is the focus of this paper. A weighted L2-norm penalty is introduced in the sound...

  3. Modeling hyporheic zone processes

    Science.gov (United States)

    Runkel, Robert L.; McKnight, Diane M.; Rajaram, Harihar

    2003-01-01

    Stream biogeochemistry is influenced by the physical and chemical processes that occur in the surrounding watershed. These processes include the mass loading of solutes from terrestrial and atmospheric sources, the physical transport of solutes within the watershed, and the transformation of solutes due to biogeochemical reactions. Research over the last two decades has identified the hyporheic zone as an important part of the stream system in which these processes occur. The hyporheic zone may be loosely defined as the porous areas of the stream bed and stream bank in which stream water mixes with shallow groundwater. Exchange of water and solutes between the stream proper and the hyporheic zone has many biogeochemical implications, due to differences in the chemical composition of surface and groundwater. For example, surface waters are typically oxidized environments with relatively high dissolved oxygen concentrations. In contrast, reducing conditions are often present in groundwater systems leading to low dissolved oxygen concentrations. Further, microbial oxidation of organic materials in groundwater leads to supersaturated concentrations of dissolved carbon dioxide relative to the atmosphere. Differences in surface and groundwater pH and temperature are also common. The hyporheic zone is therefore a mixing zone in which there are gradients in the concentrations of dissolved gasses, the concentrations of oxidized and reduced species, pH, and temperature. These gradients lead to biogeochemical reactions that ultimately affect stream water quality. Due to the complexity of these natural systems, modeling techniques are frequently employed to quantify process dynamics.

  4. Characteristics and Dynamics of a Large Sub-Tidal Sand Wave Field—Habitat for Pacific Sand Lance (Ammodytes personatus, Salish Sea, Washington, USA

    Directory of Open Access Journals (Sweden)

    H. Gary Greene

    2017-10-01

    Full Text Available Deep-water sand wave fields in the San Juan Archipelago of the Salish Sea and Pacific Northwest Washington, USA, have been found to harbor Pacific sand lance (PSL, Ammodytes personatus, a critical forage fish of the region. Little is known of the dynamics of these sand waves and the stability of the PSL sub-tidal habitats. Therefore, we have undertaken an initial investigation to determine the dynamic conditions of a well-known PSL habitat in the San Juan Channel within the Archipelago using bottom sediment sampling, an acoustical doppler current profiling (ADCP system, and multi-beam echo sounder (MBES bathymetry. Our study indicates that the San Juan Channel sand wave field maintained its shape and bedforms geometry throughout the years it has been studied. Based on bed phase diagrams for channelized bedforms, the sand waves appear to be in a dynamic equilibrium condition. Sea level rise may change the current regime within the Archipelago and may alter some of the deep-water or sub-tidal PSL habitats mapped there. Our findings have global significance in that these dynamic bedforms that harbor PSL and sand-eels elsewhere along the west coast of North America and in the North Sea may also be in a marginally dynamic equilibrium condition and may be prone to alteration by sea level rise, indicating an urgency in locating and investigating these habitats in order to sustain the forage fish.

  5. Strontium isotope record of seasonal scale variations in sediment sources and accumulation in low-energy, subtidal areas of the lower Hudson River estuary

    Science.gov (United States)

    Smith, J.P.; Bullen, T.D.; Brabander, D.J.; Olsen, C.R.

    2009-01-01

    Strontium isotope (87Sr/86Sr) profiles in sediment cores collected from two subtidal harbor slips in the lower Hudson River estuary in October 2001 exhibit regular patterns of variability with depth. Using additional evidence from sediment Ca/Sr ratios, 137Cs activity and Al, carbonate (CaCO3), and organic carbon (OCsed) concentration profiles, it can be shown that the observed variability reflects differences in the relative input and trapping of fine-grained sediment from seaward sources vs. landward sources linked to seasonal-scale changes in freshwater flow. During high flow conditions, the geochemical data indicate that most of the fine-grained sediments trapped in the estuary are newly eroded basin materials. During lower (base) flow conditions, a higher fraction of mature materials from seaward sources with higher carbonate content is trapped in the lower estuary. Results show that high-resolution, multi-geochemical tracer approaches utilizing strontium isotope ratios (87Sr/86Sr) can distinguish sediment sources and constrain seasonal scale variations in sediment trapping and accumulation in dynamic estuarine environments. Low-energy, subtidal areas such as those in this study are important sinks for metastable, short-to-medium time scale sediment accumulation. These results also show that these same areas can serve as natural recorders of physical, chemical, and biological processes that affect particle and particle-associated material dynamics over seasonal-to-yearly time scales. ?? 2009.

  6. Hardened subtidal stromatolites, bahamas.

    Science.gov (United States)

    Dravis, J J

    1983-01-28

    Hardened, high-relief stromatolites have been discovered along the margins of some Bahamian platforms. They occur in high-energy (tidal) oolitic sand environments in waters ranging in depth from about 1 to 5 meters. Physical stress produced by actively migrating bed forms of oolitic sand appears to exclude grazing gastropods and subsequent community successions, permitting stromatolite growth.

  7. Bioecology of subtidal region

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.

    stream_size 2 stream_content_type text/plain stream_name Mar_Archaeol_2_69.pdf.txt stream_source_info Mar_Archaeol_2_69.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  8. Structural organization of process zones in upland watersheds of central Nevada and its influence on basin connectivity, dynamics, and wet meadow complexes

    Science.gov (United States)

    Jerry R. Miller; Mark L. Lord; Lionel F. Villarroel; Dru Germanoski; Jeanne C. Chambers

    2012-01-01

    The drainage network within upland watersheds in central Nevada can be subdivided into distinct zones each dominated by a unique set of processes on the basis of valley form, the geological materials that comprise the valley floor, and the presence or absence of surficial channels. On hillslopes, the type and structure (frequency, length, and spatial arrangement) of...

  9. Subtidal eelgrass/macroalgae surveys for the proposed breakwaters at the US Coast Guard Station at Ediz Hook, Washington, March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Shreffler, D.K. [Battelle/Marine Sciences Lab., Sequim, WA (US)

    1993-05-01

    In 1993, the US Coast Guard proposed to construct two breakwaters and a debris boom to protect its existing pier and moored vessels inside Ediz Hook in Port Angeles Harbor, Washington. To assist the US Army Corps of Engineers -- Seattle District in determining the potential environmental impacts of the proposed breakwaters, Battelle/Marine Sciences Laboratory performed subtidal SCUBA surveys as specified in the Washington Department of Fisheries intermediate eelgrass/macroalgae habitat survey guidelines. The objectives of the subtidal surveys were to (1) quantify the shoot densities of eelgrass; (2) provide percent cover estimates for non-eelgrass macroalgae species; (3) develop a site map indicating the qualitative distribution of eelgrass/macroalgae species, substrate characterization, approximate depth contours, and the approximate location of the proposed project features; and (4) document the time and date of the surveys, turbidity/visibility, presence of invertebrate/vertebrate species, and anecdotal observations pertinent to habitat characterization of the project site. A total of 14 dives along 12 transects (T1--T12) were successfully completed between March 15 and March 17, 1993. Eelgrass was observed on all of the transects except T7 and T8 at the western debris barrier and T12 along the waterward margin of the existing T-pier. The vicinity of the proposed east breakwater had the highest eelgrass shoot densities (up to 89 shoots/m{sup 2}) observed by the divers. Macroalgae and invertebrate species diversity were also highest at the east breakwater site. The low eelgrass densities observed at the west debris barrier site (0 to 14 shoots/m{sup 2}) can be attributed mostly to the lack of suitable substrate. The existing layer of wood debris armoring the bottom at the west project site currently limits, and in the areas of heaviest deposition probably precludes, the growth of eelgrass. As was expected, no eelgrass was observed at the south breakwater site.

  10. Assessing the Influence of the Automobile Traffic on the Amphibians and Reptiles in the Buffer Zone of Biosphere Reserve “Srebarna” (NE Bulgaria

    Directory of Open Access Journals (Sweden)

    Ivelin A. Mollov

    2013-12-01

    Full Text Available Currently the problem of the effects of the road network and traffic on the amphibians and reptiles in Bulgaria is poorly studied. During the period March 2002 - March 2004 in the Buffer Zone of Biosphere Reserve "Srebarna" (NE Bulgaria were built two anti-fire roads from the eastern and western side of the lake in area of grasslands of semi-steppe type, typical for north-eastern Bulgaria. The aim of the constructed roads is to provide access for fire vehicles to areas in and around the reserve. The current study aims to provide data on the impact of road traffic and the newly constructed road network and another previously existing road on the amphibians and reptiles inhabiting the buffer zone of the biosphere reserve "Srebarna". For the entire period of study in the three studied road sections a total of 15 dead specimens of amphibians belonging to 4 species (Bombina bombina, Hyla arborea, Bufo bufo, Bufo viridis and 70 dead specimens of reptiles belonging to 8 species (Emys orbicularis, Ablepharus kitaibelii, Lacerta viridis, Podarcis tauricus, Podarcis muralis, Natrix natrix, Coronella austriaca and Dolichophis caspius were recorded. Several “hot spots”, where most cadavers were recorded are well described and possible conservation measures are discussed.

  11. Influence of coal deposits on permafrost degradation in the shelf zone of arctic seas and methane emission into the water column

    Science.gov (United States)

    Burov, B. A.; Gresov, A. I.

    2011-09-01

    Influence of coal beds on degradation (melting) of sea bottom Arctic shelf permafrost is investigated by means of mathematical modeling methods. Estimation of methane flux from thawing coal seam into water layer is presented

  12. Synaptic vesicle proteins and active zone plasticity

    Directory of Open Access Journals (Sweden)

    Robert J Kittel

    2016-04-01

    Full Text Available Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone. The complex molecular architecture of active zones mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of active zones vary significantly, even for a given connection. Thus, there appear to be distinct active zone states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the active zone.The protein-rich cytomatrix at the active zone (CAZ provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1 and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and active zone states, which has heretofore received little attention.

  13. New geometrical compactness measures for zones design

    Directory of Open Access Journals (Sweden)

    Eric Alfredo Rincón-García

    2012-07-01

    Full Text Available The design of compact zones has been studied because of its influence in the creation of zones with regular forms, which are easier to analyze, to investigate or to administer. This paper propose a new method to measure compactness,by means of the transformation of the original geographical spaces, into figures formed with square cells, which are used to measure the similarity between the original zone and an ideal zone with straight forms. The proposed method was applied to design electoral zones, which must satisfy constraints of compactness, contiguity and population balance, in a topographical configuration that favors the creation of twisted and diffuse shapes. The results show that the new method favors the creation of zones with straight forms, without an important effect to the population balance, which are considered zones of high quality. Keywords: Redistricting, compactness, simulated annealing, GIS. Mathematics Subject Classification: 90C59, 90C29, 68T20.

  14. Subtidal benthic megafauna in a productive and highly urbanised semi-enclosed bay (Ría de Vigo, NW Iberian Peninsula)

    Science.gov (United States)

    Aneiros, Fernando; Rubal, Marcos; Troncoso, Jesús S.; Bañón, Rafael

    2015-11-01

    The Ría de Vigo is a semi-enclosed bay with high primary productivity due to the influence of coastal upwelling-downwelling dynamics. The area is heavily populated and affected by numerous human activities, which lead to sediment modification. Epibenthic megafauna from the non-estuarine zones of this bay has been studied in order to describe its spatial distribution, testing possible differences between inner and outer areas. With that purpose, 75 sites have been sampled by means of a towing dredge. Megafauna was identified to the lowest taxonomic level possible, and each taxon counted and weighted. 113 different taxa were identified and a high spatial heterogeneity was observed in terms of abundance, biomass, taxa richness, diversity and evenness. Suspension-feeding molluscs dominated the innermost part of the studied area, and were substituted by echinoderms towards the external zones; this spatial pattern was also reflected in the results of multivariate analyses. These shifts in taxonomic and trophic guild composition of the assemblages have been tentatively related to differences in pollution levels and primary productivity along the main axis of the bay.

  15. The Influence of Land Subsidence, Quarrying, Drainage, Irrigation and Forest Fire on Groundwater Resources and Biodiversity Along the Southern Po Plain Coastal Zone (Italy)

    Science.gov (United States)

    Antonellini, M. A.; Mollema, P. N.

    2014-12-01

    The coastal zone of the southern Po plain is characterized by low lying land, which is reclaimed to permit settlements and agriculture. The history, tourism resorts and peculiar coastal environments make this territory attractive and valuable. Natural and fluid-extraction-induced land subsidence along with coastal erosion are major problems. Touristic development has strongly modified the landscape; coastal dunes have been in part removed to make room for hotels and quarrying has caused the formation of gravel pit lakes close to the shoreline. Protected natural areas include a belt of coastal dunes, wetlands, and the internal historical forests of San Vitale and Classe. The dunes have largely lost their original vegetation ecosystem, because years ago they have been colonized with pine trees to protect the adjacent farmland from sea spray. These pine forests are currently a fire hazard. Land reclamation drainage keeps the water table artificially low. Results of these anthropogenic disturbances on the hydrology include a decrease in infiltration rates, loss of freshwater surface bodies, encroachment of saltwater inland from the river estuaries, salinization of the aquifer, wetlands and soil with a loss in plant and aquatic species biodiversity. Feedback mechanisms are complex: as land subsidence continues, drainage increases at the same pace promoting sea-water intrusion. The salinity of the groundwater does not allow for plant species richness nor for the survival of large pine trees. Farmland irrigation and fires in the pine forests, on the other hand, allow for increased infiltration and freshening of the aquifer and at the same time promote plant species diversity. Our work shows that the characteristics of the southern Po coastal zone require integrated management of economic activities, natural areas, and resources. This approach is different from the ad hoc measures taken so far, because it requires long term planning and setting a priority of objectives.

  16. PTSD and trauma in Austria's elderly: influence of wartime experiences, postwar zone of occupation, and life time traumatization on today's mental health status—an interdisciplinary approach

    Directory of Open Access Journals (Sweden)

    Tobias M. Glück

    2012-07-01

    Full Text Available Background: While in recent years epidemiological studies on World War (WW II-related traumatization and prevalence of posttraumatic stress disorder (PTSD in elderly persons have been conducted for various European countries, for Austria, these numbers are unknown. Objective: The focus of this epidemiologic study was to picture the current mental health status and prevalence of PTSD and lifetime traumatic events in Austria's elderly with respect to WWII and subsequent occupation. Method: In an interdisciplinary approach of psychologists and historians, 316 elderly Austrians (born before 1946 were interviewed for symptoms of PTSD and lifetime traumatization (Traumatic Life Events Questionnaire, PTSD Checklist-Civilian Version, current mental health (Brief Symptom Inventory, wartime-related trauma, and traumatic experiences with occupational forces. These factors were also compared regarding the zone of occupation (Allied vs. Soviet. Data were collected between March and September 2010. Results: 97.5% of the sample reported at least one lifetime trauma. War-related traumata were reported by 92.7% and non-war-related traumata by 82.3%; 40.2% experienced traumatic events with occupational forces. PTSD was present in 1.9% of the sample and up to 13.9% taking subthreshold PTSD into account. Both, the presence of symptoms indicative of PTSD and subthreshold PTSD implied weaker current mental health (regarding General Distress: odds ratios up to 25.51; 95% CI = 9.82 to 66.27. Independent of PTSD diagnosis persons from the Soviet occupied zone showed higher levels of Interpersonal Sensitivity, Global Distress, and Phobic Anxiety. Prevalence of PTSD was independent of gender. Conclusions: Our results corroborate findings from other European countries that PTSD is a common disorder in the elderly due to WWII experience and that PTSD and trauma affect mental health even across long periods of time. Postwar distressing conditions also pose a further risk

  17. Influence of stretching and density contrasts on the chemical evolution of continental magmas: An example from the Ivrea-Verbano Zone

    Science.gov (United States)

    Sinigoi, S.; Quick, J.E.; Mayer, A.; Budahn, J.

    1996-01-01

    The southern Ivrea-Verbano Zone of the Italian Western Alps contains a huge mafic complex that intruded high-grade metamorphic rocks while they were resident in the lower crust. Geologic mapping and chemical variations of the igneous body were used to study the evolution of underplated crust. Slivers of crustal rocks (septa) interlayered with igneous mafic rocks are concentrated in a narrow zone deep in the complex (Paragneiss-bearing Belt) and show evidence of advanced degrees of partial melting. Variations of rare-earth-element patterns and Sr isotope composition of the igneous rocks across the sequence are consistent with increasing crustal contamination approaching the septa. Therefore, the Paragneiss-bearing Belt is considered representative of an "assimilation region" where in-situ interaction between mantle- and crust-derived magmas resulted in production of hybrid melts. Buoyancy caused upwards migration of the hybrid melts that incorporated the last septa and were stored at higher levels, feeding the Upper Mafic Complex. Synmagmatic stretching of the assimilation region facilitated mixing and homogenization of melts. Chemical variations of granitoids extracted from the septa show that deep septa are more depleted than shallow ones. This suggests that the first incorporated septa were denser than the later ones, as required by the high density of the first-injected mafic magmas. It is inferred that density contrasts between mafic melts and crustal rocks play a crucial role for the processes of contamination of continental magmas. In thick under- plated crust, the extraction of early felsic/hybrid melts from the lower crust may be required to increase the density of the lower crust and to allow the later mafic magmas to penetrate higher crustal levels.

  18. Zoning, equity, and public health.

    Science.gov (United States)

    Maantay, J

    2001-01-01

    Zoning, the most prevalent land use planning tool in the United States, has substantial implications for equity and public health. Zoning determines where various categories of land use may go, thereby influencing the location of resulting environmental and health impacts. Industrially zoned areas permit noxious land uses and typically carry higher environmental burdens than other areas. Using New York City as a case study, the author shows that industrial zones have large residential populations within them or nearby. Noxious uses tend to be concentrated in poor and minority industrial neighborhoods because more affluent industrial areas and those with lower minority populations are rezoned for other uses, and industrial zones in poorer neighborhoods are expanded. Zoning policies, therefore, can have adverse impacts on public health and equity. The location of noxious uses and the pollution they generate have ramifications for global public health and equity; these uses have been concentrated in the world's poorer places as well as in poorer places within more affluent countries. Planners, policymakers, and public health professionals must collaborate on a worldwide basis to address these equity, health, and land use planning problems. PMID:11441726

  19. Tempering-Induced Microstructural Changes in the Weld Heat-Affected Zone of 9 to 12 Pct Cr Steels and Their Influence on Sliding Wear

    Science.gov (United States)

    Velkavrh, Igor; Kafexhiu, Fevzi; Klien, Stefan; Diem, Alexander; Podgornik, Bojan

    2017-01-01

    Increasing amount of tribological applications is working under alternating high/low temperature conditions where the material is subjected to temperature fatigue mechanisms such as creep, softening due to annealing, and at the same time must withstand mechanical wear due to sliding contact with pairing bodies. Steam turbine valves, gate valves, valve heads, stems, seats and bushings, and contacting surfaces of the carrier elements are some examples of such applications. The purpose of the present study is to evaluate the potential of X20 and P91 steels as materials for applications operating under combined effect of mechanical wear and alternating high/low temperature conditions. It was focused on how the microstructural changes occurring in the weld zone affect the wear properties of the selected materials. Generally, with longer tempering time and higher tempering temperature, the number of carbide precipitates decreased, while their relative spacing increased. Before tempering, the morphology of the steel matrix (grain size, microstructure homogeneity) governed the wear resistance of both steels, while after tempering wear response was determined by the combination of the number and the size of carbide particles. After tempering, in X20 steel larger number of stable M23C6 carbides was observed as compared with P91 steel, resulting in lower wear rates. It was observed that for both steels, a similar combination of number density and size distribution of carbide particles provided the highest wear resistance.

  20. The influence of abscisic acid on the ethylene biosynthesis pathway in the functioning of the flower abscission zone in Lupinus luteus.

    Science.gov (United States)

    Wilmowicz, Emilia; Frankowski, Kamil; Kućko, Agata; Świdziński, Michał; de Dios Alché, Juan; Nowakowska, Anna; Kopcewicz, Jan

    2016-11-01

    Flower abscission is a highly regulated developmental process activated in response to exogenous (e.g. changing environmental conditions) and endogenous stimuli (e.g. phytohormones). Ethylene (ET) and abscisic acid (ABA) are very effective stimulators of flower abortion in Lupinus luteus, which is a widely cultivated species in Poland, Australia and Mediterranean countries. In this paper, we show that artificial activation of abscission by flower removal caused an accumulation of ABA in the abscission zone (AZ). Moreover, the blocking of that phytohormone's biosynthesis by NDGA (nordihydroguaiaretic acid) decreased the number of abscised flowers. However, the application of NBD - an inhibitor of ET action - reversed the stimulatory effect of ABA on flower abscission, indicating that ABA itself is not sufficient to turn on the organ separation. Our analysis revealed that exogenous ABA significantly accelerated the transcriptional activity of the ET biosynthesis genes ACC synthase (LlACS) and oxidase (LlACO), and moreover, strongly increased the level of 1-aminocyclopropane-1-carboxylic acid (ACC) - ET precursor, which was specifically localized within AZ cells. We cannot exclude the possibility that ABA mediates flower abscission processes by enhancing the ET biosynthesis rate. The findings of our study will contribute to the overall basic knowledge on the phytohormone-regulated generative organs abscission in L. luteus. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  2. Control of the Free Convection Flow within the Breathing Zone by Confluent Jets for Improved Performance of Personalized Ventilation: Part 1 – Thermal influence

    DEFF Research Database (Denmark)

    Nagano, H.; Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor

    2009-01-01

    A new method for improvement the performance of personalized ventilation (PV) by control of the free convection flow based of confluent plane jets was studied. The confluent upward plane jets were generated close to the front of human body by openings at the front edge of a desk. The inner jet...... under the condition with this PV method and there was no thermal influence by the flow except for the back of neck....

  3. The life history and its environmental regulation in the subtidal red alga, Acrosymphyton purpuriferum (J. Ag.) Sjöst.

    NARCIS (Netherlands)

    Breeman, Antje Maatje

    1979-01-01

    In this thesis a descrlption is given of the life history of the benthic marine red alga Acrosymphyton puriferum (J. Ag.) Sjöst. (Rhodophyceae, Cryptonemiales) and of the influence environmental factors have on the course of this life history. ... Zie: Summary

  4. The population structure of two sympatric hermit-crab species on a subtidal rocky shore of an island in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    DANIEL J.M. LIMA

    2014-12-01

    Full Text Available The main goal of this investigation was to characterize the population structure and shell occupancy of two sympatric hermit-crab species, Pagurus brevidactylus and Paguristes tortugae. The study was undertaken at Couves Island on the southeastern coast of Brazil, from March 2010 through February 2011, on subtidal rocky bottoms. Specimens were collected by SCUBA diving sessions. A total of 195 individuals of P. brevidactylus and 132 of P. tortugae were examined. Both populations showed unimodal size-frequency distributions, which were non-normal for P. brevidactylus and normal for P. tortugae. The median size of P. brevidactylus was significantly smaller than P. tortugae; in both species, males were significantly larger than females. For both, juveniles and ovigerous females were recorded in all size classes and in almost the entire sampling period. No significant departures from the 1:1 sex ratio were detected, although some size classes were skewed. Overlaps in shell occupation were recorded. Pagurus brevidactylus and P. tortugae showed similar population features; they reached sexual maturity at small sizes, and the nearly year-round presence of young and ovigerous females suggests continuous reproduction. These inter-specific interactions involving resource partitioning suggest a regulatory process that is probably part of the equilibrium strategy of these populations.

  5. Temporal changes in secondary production of a population of the subtidal sand snail Umbonium costatum in Hakodate Bay, northern Japan: importance of annual change in age structure

    Science.gov (United States)

    Noda, Takashi

    1997-05-01

    Year-to-year changes in age structure, biomass ( B), annual secondary production ( P) and {P}/{overlineB} ratio are described of a population of the subtidal snail Umbonium costatum in Hakodate Bay, northern Japan, during a 6-y period (1982-1988). Population structure and values of biomass and production were highly variable from year to year; the ranges of the annual mean biomass, annual production and {P}/{overlineB} ratio were 3.71-9.22 g dry tissue m -2, 1.01-4.92 g dry tissue m -2 y -1 and 0.13-1.33 y -1 respectively. Change in the age structure was the most important single factor affecting temporal changes in annual production in this population. The annual production of the population was high when young individuals, which have a small body size and high growth rate, dominated the population. While annual {P}/{overlineB} ratios in 1983 and 1984 fell within the range of values reported for various other gastropods, those in 1985, 1986, 1987 and 1988 were markedly lower, if the relation between the population {P}/{overlineB} ratio and life span is taken into account. This demonstrates that production estimates from annual biomass and life-span values may lead to incorrect results in a recruitment-limited population.

  6. Mixed effects of elevated pCO2 on fertilisation, larval and juvenile development and adult responses in the mobile subtidal scallop Mimachlamys asperrima (Lamarck, 1819).

    Science.gov (United States)

    Scanes, Elliot; Parker, Laura M; O'Connor, Wayne A; Ross, Pauline M

    2014-01-01

    Ocean acidification is predicted to have severe consequences for calcifying marine organisms especially molluscs. Recent studies, however, have found that molluscs in marine environments with naturally elevated or fluctuating CO2 or with an active, high metabolic rate lifestyle may have a capacity to acclimate and be resilient to exposures of elevated environmental pCO2. The aim of this study was to determine the effects of near future concentrations of elevated pCO2 on the larval and adult stages of the mobile doughboy scallop, Mimachlamys asperrima from a subtidal and stable physio-chemical environment. It was found that fertilisation and the shell length of early larval stages of M. asperrima decreased as pCO2 increased, however, there were less pronounced effects of elevated pCO2 on the shell length of later larval stages, with high pCO2 enhancing growth in some instances. Byssal attachment and condition index of adult M. asperrima decreased with elevated pCO2, while in contrast there was no effect on standard metabolic rate or pHe. The responses of larval and adult M. asperrima to elevated pCO2 measured in this study were more moderate than responses previously reported for intertidal oysters and mussels. Even this more moderate set of responses are still likely to reduce the abundance of M. asperrima and potentially other scallop species in the world's oceans at predicted future pCO2 levels.

  7. The influence of partial timber harvest in riparian management zones on macroinvertebrate and fish communities on first- and second-order streams in northern Minnesota

    Science.gov (United States)

    Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric; Schlesser, Nicholas

    2010-01-01

    Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m2 ha−1 or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m2 ha−1 may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.

  8. Trading Zones in Early Modern Europe.

    Science.gov (United States)

    Long, Pamela O

    2015-12-01

    This essay adopts the concept of trading zones first developed for the history of science by Peter Galison and redefines it for the early modern period. The term "trading zones" is used to mean arenas in which substantive and reciprocal communication occurred between individuals who were artisanally trained and learned (university-trained) individuals. Such trading zones proliferated in the sixteenth century. They tended to arise in certain kinds of places and not in others, but their existence must be determined empirically. The author's work on trading zones differs from the ideas of Edgar Zilsel, who emphasized the influence of artisans on the scientific revolution. In contrast, in this essay, the mutual influence of artisans and the learned on each other is stressed, and translation is used as a modality that was important to communication within trading zones.

  9. Organic matter recycling in a shallow coastal zone (NW Mediterranean): The influence of local and global climatic forcing and organic matter lability on hydrolytic enzyme activity

    Science.gov (United States)

    Misic, Cristina; Harriague, Anabella Covazzi

    2008-12-01

    Seawater and sediment were collected on a monthly basis from a shallow (10.5 m depth) coastal site in the Ligurian Sea (NW Mediterranean) from November 1993 to December 1994 to determine the main environmental forces that influenced the biogeochemical processes and to study the relationships between the availability and lability of the organic matter (OM) and hydrolytic enzymatic activity. The current direction throughout the sampling year was influenced by the climatic conditions, which showed significant correlations with north atlantic oscillation (NAO) index values. The current generally flowed northwards in spring. This could cause significantly lower transparency values than in the summer, when an eastward current probably reduced the allochthonous input of material from the main local watercourse and contributed to turning the conditions from mesotrophic to oligotrophic. Spring and summer were separated by transitional periods more than by the canonical autumn and winter seasons. These transitions were characterised by a reduction in salinity values and by resuspension caused by water column mixing and a current flowing towards the southwest. The significant inverse correlations of the chlorophyll- a and protein concentrations, bacterial abundance and proteolysis of the bottom seawater and transparency showed the direct influence of resuspension on the organic matter dynamics. Moreover, OM trophic quality influenced the bacterial parameters and the enzymatic activities. The glycolytic β glucosidase and chitinase activities and their bacterial cell-specific hydrolytic rates were higher when substrates such as hydrolysable proteins were available, while they decreased when refractory compounds were abundant. The low leucine aminopeptidase: β glucosidase ratio values observed in the water column were presumably related to the potential ease with which microbes obtained protein-derived materials and energy, the protein hydrolysable fraction being estimated at

  10. Providing plastic zone extrusion

    Science.gov (United States)

    Manchiraju, Venkata Kiran; Feng, Zhili; David, Stan A.; Yu, Zhenzhen

    2017-04-11

    Plastic zone extrusion may be provided. First, a compressor may generate frictional heat in stock to place the stock in a plastic zone of the stock. Then, a conveyer may receive the stock in its plastic zone from the compressor and transport the stock in its plastic zone from the compressor. Next, a die may receive the stock in its plastic zone from the conveyer and extrude the stock to form a wire.

  11. Vadose zone microbiology

    Energy Technology Data Exchange (ETDEWEB)

    Kieft, Thomas L.; Brockman, Fred J.

    2001-01-17

    The vadose zone is defined as the portion of the terrestrial subsurface that extends from the land surface downward to the water table. As such, it comprises the surface soil (the rooting zone), the underlying subsoil, and the capillary fringe that directly overlies the water table. The unsaturated zone between the rooting zone and the capillary fringe is termed the "intermediate zone" (Chapelle, 1993). The vadose zone has also been defined as the unsaturated zone, since the sediment pores and/or rock fractures are generally not completely water filled, but instead contain both water and air. The latter characteristic results in the term "zone of aeration" to describe the vadose zone. The terms "vadose zone," "unsaturated zone", and "zone of aeration" are nearly synonymous, except that the vadose zone may contain regions of perched water that are actually saturated. The term "subsoil" has also been used for studies of shallow areas of the subsurface immediately below the rooting zone. This review focuses almost exclusively on the unsaturated region beneath the soil layer since there is already an extensive body of literature on surface soil microbial communities and process, e.g., Paul and Clark (1989), Metting (1993), Richter and Markowitz, (1995), and Sylvia et al. (1998); whereas the deeper strata of the unsaturated zone have only recently come under scrutiny for their microbiological properties.

  12. Incorporating conservation zone effectiveness for protecting biodiversity in marine planning.

    Science.gov (United States)

    Makino, Azusa; Klein, Carissa J; Beger, Maria; Jupiter, Stacy D; Possingham, Hugh P

    2013-01-01

    Establishing different types of conservation zones is becoming commonplace. However, spatial prioritization methods that can accommodate multiple zones are poorly understood in theory and application. It is typically assumed that management regulations across zones have differential levels of effectiveness ("zone effectiveness") for biodiversity protection, but the influence of zone effectiveness on achieving conservation targets has not yet been explored. Here, we consider the zone effectiveness of three zones: permanent closure, partial protection, and open, for planning for the protection of five different marine habitats in the Vatu-i-Ra Seascape, Fiji. We explore the impact of differential zone effectiveness on the location and costs of conservation priorities. We assume that permanent closure zones are fully effective at protecting all habitats, open zones do not contribute towards the conservation targets and partial protection zones lie between these two extremes. We use four different estimates for zone effectiveness and three different estimates for zone cost of the partial protection zone. To enhance the practical utility of the approach, we also explore how much of each traditional fishing ground can remain open for fishing while still achieving conservation targets. Our results show that all of the high priority areas for permanent closure zones would not be a high priority when the zone effectiveness of the partial protection zone is equal to that of permanent closure zones. When differential zone effectiveness and costs are considered, the resulting marine protected area network consequently increases in size, with more area allocated to permanent closure zones to meet conservation targets. By distributing the loss of fishing opportunity equitably among local communities, we find that 84-88% of each traditional fishing ground can be left open while still meeting conservation targets. Finally, we summarize the steps for developing marine zoning that

  13. Carbon and Nitrogen Stable Isotope Ratios of Subtidal Benthic Invertebrates in an Estuarine Mangrove Ecosystem (Andhra Pradesh, India)

    Science.gov (United States)

    Bouillon, S.; Raman, A. V.; Dauby, P.; Dehairs, F.

    2002-05-01

    In order to assess the relative trophic importance of mangrove litterfall and aquatic primary production in the mangrove creeks of the Coringa Wildlife Sanctuary (Andhra Pradesh, India) and the adjacent semi-enclosed Kakinada Bay, carbon and nitrogen stable isotope ratios were determined in a variety of benthic invertebrate species collected at 22 sites during the pre-monsoon period (May-June) of 1997 and 1999. δ13C values showed little interspecific variation at any given location, but there was a distinct spatial gradient in consumer δ13C values of about 7‰, with more depleted values in the mangrove creeks (-23·6±0·6‰), and gradually increasing in the mangrove outlets (-21·5±0·9‰), a relatively restricted zone in the south-eastern part of Kakinada Bay adjacent to the mangroves (-18·8±0·8‰), and the central and northern part of the Bay (-16·7±1·4‰) which opens into the Bay of Bengal. This gradient is much larger than that observed during a previous study in suspended organic matter (maximum about 2·7‰) and during this study in sediment organic matter (about 1·5-2·5‰). The observed carbon stable isotope ratios thus suggest a marked selectivity of the benthic invertebrate community for pelagic and benthic microalgal food sources and indicate that mangrove-derived and other terrestrial carbon is not a significant food source for benthic invertebrate communities in this ecosystem during the pre-monsoon period. Furthermore, δ13C values of sediment organic matter (SOM) suggest that terrestrial carbon is not a major contributor to the SOM-pool in this ecosystem. Evidence for seaward migration of Penaeid prawns was provided by some individuals caught in the North Bay which displayed low δ13C values of characteristic of fauna found in the mangrove creeks or outlets. Nitrogen stable isotope ratios were found to be a useful indicator of trophic level, even though there remained some overlap between δ15N values of presumed low and higher

  14. Biodiversity and density of subtidal benthos of an oceanic tropical island (a comparison within the Pacific Ocean)

    Science.gov (United States)

    Sibaja-Cordero, Jeffrey A.; Troncoso, Jesús S.; Cortés, Jorge; Moreira, Juan; Vargas, José A.; Benavides-Varela, Catalina

    2016-09-01

    The marine macrofauna of the shallow sandy bottom of Isla del Coco, Costa Rica (5°32‧N-87°04‧W) was assessed in April 2010. Comparisons of richness, density and diversity between levels of exposure to ocean influence were carried out. During this study 15,407 specimens with a mean density of 1826 ind m- 2 were found between 3-75 m depth. The specimens were distributed in 267 taxa (29% new additions) with a mean of 55 ± 14 expected taxa m- 2. The values of density, richness and diversity were higher at the exposed coast, whereas they decreased at inner bays due to the influence of freshwater input. These estimates were compared with 40 studies in the Tropical Pacific Ocean (TPO). Taxa and density previously reported from the TPO were dependent on the area and depth range studied. Additionally, these parameters varied according to the sampling gear used. For example, higher densities were reported by using corers or boxcorers. The Shannon-Wiener index was most effective in identifying sediment and geographical patterns of variation along the TPO. Differences in these diversity parameters were also found between islands and mainland studies. Moreover, richness and density values from Isla del Coco were higher than the same parameters reported in studies using grabs in the TPO. At Isla del Coco annelids were dominant in terms of relative abundance (49.6%), followed by crustaceans (10.1%), mollusks (2.8%), and others faunal groups (37.5%). The faunistic composition at Isla del Coco differed when compared to the rest of localities of TPO due to the higher contribution of miscellaneous groups. In conclusion, the comparison with previous studies in the TPO indicate that islands like Isla del Coco have high numbers of taxa and diversity than those of the mainland, but lower density. However, this value is influenced by the sampling methodology. The taxa accumulation curve at Isla del Coco did not reach the asymptote, suggesting that an intensive sampling, especially

  15. Bored to Death: Community-Wide Effect of Predation on a Foundation Species in a Low-Disturbance Arctic Subtidal System.

    Directory of Open Access Journals (Sweden)

    Eugeniy Yakovis

    Full Text Available The strength of top-down control by consumers is predicted to decrease with latitude, but most data confirming this assumption come from latitudes <60°, while empirical studies of predation in sub-arctic and arctic marine habitats are few. A barnacle Balanus crenatus is a native foundation species in the shallow subtidal of the White Sea (65° N, hosting a diverse (250+ species assemblage of macrobenthic organisms. On mixed sediments live barnacles share primary substrates (shells and gravel with numerous empty barnacle tests, 7% of which had drill holes of an unidentified origin. We manipulated the densities of (i adult muricid whelks Boreotrophon clathratus (of previously unknown feeding habits, to check if they prey on barnacles, (ii other predators to reveal their effect on juvenile Boreotrophon, and (iii empty tests to assess the community-wide effect of predation on barnacles. The abundance of drilled empty tests in the field correlated with that of Boreotrophon. A year-long caging experiment clearly confirmed predation, showing the highest barnacle mortality and proportion of drilled tests in whelk enclosures, and the lowest--in predator exclosure treatments. Boreotrophon preferred the barnacles attached to conspecifics to those from primary substrates. Because of its scarcity Boreotrophon had a minor direct effect on barnacle abundance in the field. Yet, initially defaunated empty tests and live barnacles developed markedly different macrobenthic assemblages, suggesting a strong indirect effect of the predation. Juvenile Boreotrophon were 5-6 times less abundant in open and partial cages than in exclosures and enclosures, which indicates that the recruitment and, consequently, the abundance of Boreotrophon and its predation on Balanus are top-down controlled by apex predators. In contrast, in tropical and temperate intertidal the predation on barnacles is stronger and primarily limited by environmental stress and prey availability.

  16. Fresnel zones for ground-based antennas

    DEFF Research Database (Denmark)

    Andersen, J. Bach

    1964-01-01

    The ordinary Fresnel zone concept is modified to include the influence of finite ground conductivity. This is important for ground-based antennas because the influence on the radiation pattern of irregularities near the antenna is determined by the amplitude and phase of the groundwave. A new...

  17. Root Apex Transition Zone as Oscillatory Zone

    Directory of Open Access Journals (Sweden)

    Frantisek Baluska

    2013-10-01

    Full Text Available Root apex of higher plants shows very high sensitivity to environmental stimuli. The root cap acts as the most prominent plant sensory organ; sensing diverse physical parameters such as gravity, light, humidity, oxygen and critical inorganic nutrients. However, the motoric responses to these stimuli are accomplished in the elongation region. This spatial discrepancy was solved when we have discovered and characterized the transition zone which is interpolated between the apical meristem and the subapical elongation zone. Cells of this zone are very active in the cytoskeletal rearrangements, endocytosis and endocytic vesicle recycling, as well as in electric activities. Here we discuss the oscillatory nature of the transition zone which, together with several other features of this zone, suggest that it acts as some kind of command centre. In accordance with the early proposal of Charles and Francis Darwins, cells of this root zone receive sensory information from the root cap and instruct the motoric responses of cells in the elongation zone.

  18. Production of Crangon crangon in the tidal zone of the Dutch Wadden Sea

    Science.gov (United States)

    Kuipers, B. R.; Dapper, R.

    The density and size of shrimps on an extensive tidal flat in the western Wadden Sea was followed through 4 successive years. The population consists of juvenile shrimps (< 35 mm) that enter the area in May and remain in the tidal zone till October-November. During these months there is a constant shift of shrimps that reached a length of 30 to 35 mm towards the subtidal, whereas at the same time new larvae settle on the tidal flats throughout the warmer part of the year with peak settlement during May and June. Shrimps that did not reach 30 to 35 mm by October do enter the tidal zone again the next spring. With aid of independant growth data the production of juvenile shrimps in the tidal zone was estimated at 2.35 g ADW·m -2·a -1, of which about 60% is consumed within the area by crabs and fishes. The average food consumption of the juvenile shrimps was estimated at 6.7 g ADW·m -2·a -1, which makes them the most important carnivore population of the Wadden Sea's tidal area.

  19. Aerosol pollution in urban and industrialized area under marine influence: physical-chemistry of particles; Les aerosols de pollution en zone urbaine et industrielle sous influence marine: physico-chimie des particules

    Energy Technology Data Exchange (ETDEWEB)

    Rimetz, J

    2007-12-15

    Harbors for trade are known as highly urbanized and industrialized areas with important maritime, railway and road traffic. Industries are mainly represented by steel, cement works, and oil refineries. The maritime sector is becoming an even larger source of air pollution. Atmospheric NO{sub x}, SO{sub 2}, O{sub 3} levels and chemical analysis of airborne particulate matter were monitored in Dunkerque conurbation in 2005 and 2006. This study was included in the IRENI program. In low-pressure conditions, local pollutants are spread out far away the agglomeration, whereas, in high-pressure regimes, the atmospheric stability and sea-breezes allow an accumulation of pollutants over the urban zone. Size-resolved chemical analyses of particulate matter collected as function of the aerodynamic diameter (D{sub a}) were performed. Ions (Na{sup +}, NH{sub 4}{sup +}, Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}), metals (Fe, Zn, Pb, Cd,...) and organic fraction (EC, OC) are associated with sub- or/and super-micron particles. The size, morphology and chemical species of individual particles collected selectively in the 12O{sub 3}, Fe{sub 3}O{sub 4}, PbO,... containing particles emitted in the Dunkerque harbour area and aged sea-salt aerosol particles (NaCl, NaNO{sub 3},...) from long range transport of air masses. Thin organic coatings from natural and anthropogenic origin are observed on the particles by ToF-SIMS imaging. (author)

  20. Zoning Districts - Volusia County HUB Zones

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Historically Underutilized Business (HUB) Zones in Volusia County. Go to http://www.sba.gov/hubzone or contact the Department of Economic Development (386) 248-8048...

  1. Driver decision-making in the dilemma zone - Examining the influences of clearance intervals, enforcement cameras and the provision of advance warning through a panel data random parameters probit model.

    Science.gov (United States)

    Savolainen, Peter T; Sharma, Anuj; Gates, Timothy J

    2016-11-01

    In recent years, there have been a series of innovations in the field of vehicle detection at intersection approaches. Modern radar-based smart sensors make it possible to track individual vehicles in close proximity to an intersection. These advancements in technology potentially enable the provision of vehicle- and site-specific decision dilemma zone protection at the onset of the yellow indication at signalized intersections. To exploit this opportunity, it is critical to develop an in-depth understanding of those factors influencing a driver's decision to stop or go at the onset of yellow. This study investigates how signal timing strategies such as yellow interval durations, all-red clearance intervals, advance warning flashers, and automated camera enforcement affect driver decision-making. Data from 87 intersection approaches across five regions of the United States are used to develop a series of decision (i.e., probability of stopping) curves using vehicle trajectory and signal phasing data. A panel data random parameters probit model is used to account for heterogeneity across locations, as well as correlation in driver decision-making, due to unobserved factors that are unique to each signalized intersection. The results demonstrate drivers are more likely to stop at locations where enforcement cameras or flashers are present. Stopping was also more prevalent at intersections with lower speed limits, longer crossing distances, and where pedestrian crosswalks were present. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Focusing on the Interfaces, Estuaries and Redox Transition Zones, for Understanding the Microbial Processes and Biogeochemical Cycling of Carbon under the Looming Influence of Global Warming and Anthropogenic Perturbations

    Science.gov (United States)

    Dang, H.; Jiao, N.

    2013-12-01

    the phytoplankton, zooplankton and fish communities in major world estuaries and coastal oceans. However, due to the rapid evolution rate and high adaptive nature of environmental microorganisms, global warming and anthropogenic perturbations may change the structure and function of the aquatic microbial communities. The estuarine redox transition zones may harbor diverse and novel microbial function groups and communities. How the different microbial processes may influence the ecological functionality and efficiency of estuarine ecosystems needs to be thoroughly investigated to be fully understood.

  3. Techniques for determining physical zones of influence

    Science.gov (United States)

    Hamann, Hendrik F; Lopez-Marrero, Vanessa

    2013-11-26

    Techniques for analyzing flow of a quantity in a given domain are provided. In one aspect, a method for modeling regions in a domain affected by a flow of a quantity is provided which includes the following steps. A physical representation of the domain is provided. A grid that contains a plurality of grid-points in the domain is created. Sources are identified in the domain. Given a vector field that defines a direction of flow of the quantity within the domain, a boundary value problem is defined for each of one or more of the sources identified in the domain. Each of the boundary value problems is solved numerically to obtain a solution for the boundary value problems at each of the grid-points. The boundary problem solutions are post-processed to model the regions affected by the flow of the quantity on the physical representation of the domain.

  4. Adaptation and stress defence in intertidal and subtidal Antarctic limpets (Nacella concinna):A study of the plasticity of molecular and biochemical stress response in Antarctic invertebrates

    OpenAIRE

    Weihe, Ellen

    2010-01-01

    In the summer months, a subpopulation of the Antarctic limpet Nacella concinna migrates into the intertidal zone, which becomes increasingly ice-free and expands by glacier retreat due to global warming. Animals inhabiting intertidal zones are air exposed twice a day during low tide while sub-littoral animals are always covered by water. Intertidal and permanently sub-littoral N. concinna can easily be distinguished by their shell morphology. To test whether these morphological differences ar...

  5. Influencia de los parámetros de corte en el espesor de la zona de deformación plástica secundaria // Influence of cutting parameters on the thickness of the secondary-plastic-deformation zone

    Directory of Open Access Journals (Sweden)

    Tania Rodríguez - Moliner

    2010-09-01

    Full Text Available Este trabajo tiene como objetivo estudiar la influencia de los parámetros de corte en el espesor de lazona de deformación plástica secundaria (ezdps, utilizando calzos recubiertos con nano capas deTiN/TiAlN en un acero AISI 1045. Los resultados han sido comparados contra los obtenidos con unacuchilla calzada convencional de la firma SANDVIK con recubrimientos de TiCN-Al2O3-TiN,posibilitando el estudio del efecto de los recubrimientos nano-capas en el proceso de corte demetales.Los resultados obtenidos demuestran que los efectos de la profundidad de corte y la velocidad deavance en el ezdps, usando cuchillas recubiertas con nano capas, siguen la misma tendencia que enlas cuchillas convencionales aunque con valores mucho menores. A medida que la profundidad decorte y la velocidad de avance aumentan el ezdps aumenta proporcionalmente. Estos resultados secorresponden con los obtenidos por otros autores usando cuchillas convencionales.Palabras claves: Deformación plástica secundaria, viruta, corte de metales, cuchillas recubiertas connanocapas.___________________________________________________________________________AbstractThe aim of this paper is to study the influence of the cutting parameters in the thickness of thesecondary plastic deformation zone (ezdps, for nano-layered (TiN/TiAlN cutting tools. The resultshave been compared with the ones obtained for a conventional cutting tool.The results show the effects of cutting speed, cut thickness and advance speed on the ezdps. Theezdps increases as the cut thickness, and advance speed increases. The effect of the cutting speedis contrary to the others. These results agree with the trend obtained by previous investigators,although the values obtained for the nano-layered-coated cutting tool are lower than withconventional tools.Key words: Secondary plastic deformation, chip, cutting metals, nano-layered-coated cutting tool.

  6. Boron cycling in subduction zones

    OpenAIRE

    Palmer, Martin R.

    2017-01-01

    Subduction zones are geologically dramatic features, with much of the drama being driven by the movement of water. The “light and lively” nature of boron, coupled with its wide variations in isotopic composition shown by the different geo-players in this drama, make it an ideal tracer for the role and movement of water during subduction. The utility of boron ranges from monitoring how the fluids that are expelled from the accretionary prism influence seawater chemistry, to the subduction of c...

  7. Investigating Aquatic Dead Zones

    Science.gov (United States)

    Testa, Jeremy; Gurbisz, Cassie; Murray, Laura; Gray, William; Bosch, Jennifer; Burrell, Chris; Kemp, Michael

    2010-01-01

    This article features two engaging high school activities that include current scientific information, data, and authentic case studies. The activities address the physical, biological, and chemical processes that are associated with oxygen-depleted areas, or "dead zones," in aquatic systems. Students can explore these dead zones through both…

  8. Work zone safety analysis.

    Science.gov (United States)

    2013-11-01

    This report presents research performed analyzing crashes in work zones in the state of New Jersey so as to : identify critical areas in work zones susceptible to crashes and key factors that contribute to these crashes. A field : data collection on ...

  9. Green zoning regulation under price discrimination

    Directory of Open Access Journals (Sweden)

    Hamid Hamoudi

    2017-06-01

    Full Text Available This study aims to examine urban zoning within a linear city in a Bertrand duopolistic competition framework with price discrimination and linear transportation costs. It analyses the effects of introducing an environmental area where economic and residential activity are not allowed. The welfare function used to determine the optimal size of the green area allows for a possible regulator’s bias in favour of firms/consumers. It is shown that location-price competition can be either reduced or increased depending on the size of the green area. The results indicate when a regulator implements green zoning, under linear transportation costs, influences the optimal location of firms (because these locations depend on the size of the green zone. In consequence, zoning may be used as an effective industrial or urban policy tool.

  10. Management zones in coffee cultivation

    Directory of Open Access Journals (Sweden)

    João L. Jacintho

    Full Text Available ABSTRACT This study aimed to apply precision agriculture techniques in coffee production, using correlation analysis in the definition of management zones. This work was carried out in a 22-ha area of coffee (Coffea arabica L., cv. ‘Topázio MG 1190’, which was sampled on a regular grid, using a topographic GPS, totaling 64 georeferenced samples (on average, 2.9 points per ha. Descriptive analysis was used in the data, followed by Pearson’s correlation analysis at 0.05 significance between soil chemical attributes, agronomic characteristics of the plants and altitude. It was possible to verify the correlation of soil chemical attributes, agronomic characteristics of the plants and altitude with coffee yield. Altitude was the variable most correlated with coffee yield through correlation analysis. Therefore, it was chosen as the best variable to define management zones and thematic maps capable to support coffee farmers. Three maps were generated to characterize the area in two, three and four management zones. There was a direct influence on mean yield.

  11. Features of changes periglacial formation in the zone of transport facilities (for example Dneprodzerzhinsk.

    Directory of Open Access Journals (Sweden)

    Mokritskaya T.

    2013-09-01

    Full Text Available The regularities of variability geological conditions in the zone of transport facilities in the areas of technological soaking and strains.The criteria of disorders of the array in the zone of influence of the transport facilities.

  12. VT Data - Zoning 20120709, Huntington

    Data.gov (United States)

    Vermont Center for Geographic Information — Zoning district data for the Town of Huntington, Vermont. For details regarding each zoning district refer to the current zoning regulations on town of Huntington's...

  13. VT Data - Zoning 20130529, Readsboro

    Data.gov (United States)

    Vermont Center for Geographic Information — Models a municipality’s zoning zones and related information. Data were originally created by John Whitman of Readsboro in 2004 as prooposed zoning, and were adopted...

  14. BLM Solar Energy Zones

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Priority development areas for utility-scale solar energy facilities as identified in the Solar PEIS Record of Decision. An additional Solar Energy Zone identified...

  15. Optimal exploration target zones

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2008-09-01

    Full Text Available This research describes a quantitative methodology for deriving optimal exploration target zones based on a probabilistic mineral prospectivity map. In order to arrive at out objective, we provide a plausible answer to the following question: "Which...

  16. Buffer Zone Fact Sheets

    Science.gov (United States)

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

  17. Investigating the Evolution of Southern California Salt Marshes: A Facies Model to Understand the Influence of Seismic Events on Environmental Resiliency and Sustainability

    Science.gov (United States)

    Aranda, A. N.; Carlin, J. A.; Rhodes, B. P.; Kirby, M.

    2016-02-01

    Only 10-20% of the US Pacific coast is estimated to be suitable for marsh development. In southern California specifically, marshes are disappearing ecosystems due to high population and urbanization. The future environmental impacts from climate change on these ecosystems are complicated not only by anthropogenic influences, but also by seismic activity in the region. In general, marsh evolution and response to seismic activity has yet to be fully explored in southern California. This study aims to develop a sediment facies model for salt marsh evolution in southern California by utilizing the salt marshes of the Seal Beach Wetlands (SBW). The SBW is an ideal location to develop the facies model because it straddles the active Newport-Inglewood Fault Zone. We collected sediment cores from the SBW that underwent a variety of sedimentological and geochemical analyses including grain size, X-Ray Fluorescence core scanning, magnetic susceptibility, and loss-on-ignition.. The results show a facies model consisting of sequences of marsh accretion punctuated by seismic events. These seismic events caused the marsh to subside, effectively re-setting marsh development from peat generation at a vegetated marsh state, to subtidal to intertidal mud deposition. The model also allowed us to qualify and quantify marsh recovery as inferred from event intensity, where what we perceived as more intense events resulted in more significant ecosystem disturbances and longer recovery times. Understanding this interplay between seismic activity and marsh development highlights the fragile nature of these ecosystems to climate change and sea level rise, as these stresses will only become amplified by seismic events.

  18. The Influences of Drought and Land-Cover Conversion on Inter-Annual Variation of NPP in the Three-North Shelterbelt Program Zone of China Based on MODIS Data.

    Directory of Open Access Journals (Sweden)

    Dailiang Peng

    Full Text Available Terrestrial ecosystems greatly contribute to carbon (C emission reduction targets through photosynthetic C uptake.Net primary production (NPP represents the amount of atmospheric C fixed by plants and accumulated as biomass. The Three-North Shelterbelt Program (TNSP zone accounts for more than 40% of China's landmass. This zone has been the scene of several large-scale ecological restoration efforts since the late 1990s, and has witnessed significant changes in climate and human activities.Assessing the relative roles of different causal factors on NPP variability in TNSP zone is very important for establishing reasonable local policies to realize the emission reduction targets for central government. In this study, we examined the relative roles of drought and land cover conversion(LCC on inter-annual changes of TNSP zone for 2001-2010. We applied integrated correlation and decomposition analyses to a Standardized Evapotranspiration Index (SPEI and MODIS land cover dataset. Our results show that the 10-year average NPP within this region was about 420 Tg C. We found that about 60% of total annual NPP over the study area was significantly correlated with SPEI (p<0.05. The LCC-NPP relationship, which is especially evident for forests in the south-central area, indicates that ecological programs have a positive impact on C sequestration in the TNSP zone. Decomposition analysis generally indicated that the contributions of LCC, drought, and other Natural or Anthropogenic activities (ONA to changes in NPP generally had a consistent distribution pattern for consecutive years. Drought and ONA contributed about 74% and 23% to the total changes in NPP, respectively, and the remaining 3% was attributed to LCC. Our results highlight the importance of rainfall supply on NPP variability in the TNSP zone.

  19. Influence d'une infection expérimentale à Trypanosoma congolense sur la fonction sexuelle des béliers Djallonké et Sahéliens en zone subhumide

    Directory of Open Access Journals (Sweden)

    Sangare, M.

    2010-01-01

    Full Text Available Influence of an experimental Trypanosoma congolense infection on the reproductive function of Djallonké and Sahelian rams in subhumid zone. To measure the effect of African animal trypanosomosis (AAT on male reproductive function, eight 18-24 month old Djallonké (ID; 31.2 ± 2.95 kg and Sahelian (IS; 41.7 ± 4.64 kg rams were infected with 104 Trypanosoma congolense. Eight other Djallonké (CD and Sahelian (CS rams with similar bodyweight and ages were used as uninfected controls. Four weeks after infection, ID and IS were treated with a trypanocidal drug, while maintained under observation. The evolution of clinical parameters shows a higher aptitude of Djallonké than Sahelian to control the effects of infection. This interbreed difference in susceptibility to AAT was confirmed by the higher weight losses in IS (-31.3 g when compared to ID (-12.8 g as to CD and CS rams. The effect of a T. congolense infection consisted in a decreased libido in IS (33 s when compared to ID (22.1 s (P > 0.05. The results indicate a significant effect of breed on ejaculate volume (CS: 1.23 ml vs CD: 0.88 ml; P < 0.05. Otherwise, breed did not significantly affect the other spermatic parameters. CD sperm cells concentration (3,293.4 x 106.ml-1, total abnormality rate (15.3%, dead sperm cells rate (13.9%, mobile sperm cells rate (75.5%, individual (3.76 and mass motilities (3.94 did not differ (P > 0.05 from those of CS (respectively 3,481.7 x 106.ml-1; 17.3%; 12.4%; 74.9%; 3.77; 3.36. However, the later produced 26% more total sperm cells than CD (P > 0.05. The infection reduced ejaculate volume by 15.8 and 14.5%, (P > 0.05, production of total sperm cells by 18.2 and 13.3% (P > 0.05 and the rate of mobile sperm cells by 14.2 and 27.9% (P < 0.05 respectively for Djallonké and Sahelian rams. The results show a dysfunctional state of testicles due to the harmful effects of AAT infection, hence the increase in dead sperm cells by 69.8 and 74.3% (P > 0.05 and in

  20. ZoneLib

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob; Schiøler, Henrik

    2006-01-01

    We present a dynamic model for climate in a livestock building divided into a number of zones, and a corresponding modular Simulink library (ZoneLib). While most literature in this area consider air flow as a control parameter we show how to model climate dynamics using actual control signals...... for the ventilation equipment. To   overcome a shortcoming in Simulink to solve algebraic equations and matrix inversions, we have developed the library inspired by the so called dynamic node technique. We present simulation results using the presented library, and concludes with visions for further...

  1. Grid zone drone

    OpenAIRE

    McCarthy, Clive; Cooper, Graham; Field, James; Thayne, Martyn; Vickers, Richard

    2014-01-01

    From 16th – 19th October 2014, co_LAB presented its newest creation, Grid Zone Drone, at Kinetica – an international exhibition providing a global platform for galleries, curatorial groups, design studios and artists working with new media art. 2014 marked the third consecutive year that the University of Lincoln has been represented at the global art fair. Grid Zone Drone represents a continuation of the group’s research into ‘drone culture’, and explores the detachment of the drone withi...

  2. Optimal exploration target zones

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2008-09-01

    Full Text Available , Carranza, Stein, van der Meer Introduction to Remote Sensing Background and Objective of the study Methodology Results Optimal Exploration Target Zones Pravesh Debba1, Emmanual M.J. Carranza2, Alfred Stein2, Freek D. van der Meer2 1CSIR, Logistics... and Quantitative Methods, CSIR Built Environment 2International Institute for Geo-Information Science and Earth Observation (ITC), Hengelosestraat 99, P.O. Box 6, 7500AA Enschede, The Netherlands Optimal Exploration Target Zones Debba, Carranza, Stein, van der Meer...

  3. Zones of emotional labour

    DEFF Research Database (Denmark)

    Strøbæk, Pernille Solveig

    2011-01-01

    The paper suggests that due to the difficult nature of their work public family law caseworkers are to be included in the definition of emotional labour even though they are omitted by Hochschild. Based upon a review of the structures involved in emotional labour an explorative qualitative study...... is put forth among 25 Danish public family law caseworkers. The study points to personal, professional, and social zones of emotional labour through which the caseworkers carry out their work. Emotional labour zones mark emotion structures that may be challenging due to complex emotional intersections...

  4. Arid Zone Hydrology

    Science.gov (United States)

    Arid zone hydrology encompasses a wide range of topics and hydro-meteorological and ecological characteristics. Although arid and semi-arid watersheds perform the same functions as those in humid environments, their hydrology and sediment transport characteristics cannot be readily predicted by inf...

  5. Zone of Nigeria

    African Journals Online (AJOL)

    Affected by Fertilizer in the Southern Guinea Savanna. Zone of Nigeria ... soybean varieties and the requirement by the exotic varieties ... Deficiencies of nitrogen and phosphorus ... maize at the time of sowing soybean. Maize ..... when cut open were pinkish red in colour. 56 ..... release from root of alfalfa and soybean grown.

  6. Coastal Zone of Cameroon

    African Journals Online (AJOL)

    komla

    A biogeochemical model of water, salt and nutrients budgets for two estuarine systems within Cameroon's coastal zone (Latitudes 2°— 1 3°N, Longitudes ... along ecological food webs and the earth's along an approximate 25,000 km along ...... Cameroon. Cameroon Wildlife and. Conservation Society Consultancy Report.

  7. Zone of intrusion study.

    Science.gov (United States)

    2010-10-15

    The Midwest Roadside Safety Facility (MwRSF) performed an analysis using LS-DYNA simulation to investigate the zone of intrusion (ZOI) of an NCHRP Report No. 350 2000p pickup truck when impacting a 40-in. high F-shape parapet. : The ZOI for the 40-in...

  8. Buffer Zone Sign Template

    Science.gov (United States)

    The certified pesticide applicator is required to post a comparable sign, designating a buffer zone around the soil fumigant application block in order to control exposure risk. It must include the don't walk symbol, product name, and applicator contact.

  9. Empowerment Zones and Enterprise Districts - MDC_EnterpriseZone

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Polygon feature class of Miami Dade County Enterprise Zones. Enterprise Zones are special areas in the county where certain incentives from the State are available...

  10. [Research advances in macroinvertebrate ecology of the stream hyporheic zone].

    Science.gov (United States)

    Zhang, Yue-Wei; Yuan, Xing-Zhong; Liu, Hong; Ren, Hai-Qing

    2014-11-01

    The stream hyporheic zone is an ecotone of surface water-ground water interactions, which is rich in biodiversity, and is an important component of stream ecosystem. The macroinvertebrates, which are at the top of food webs in the hyporheic zone to directly influence the matter and energy dynamics of the hyporheic zone, and are potential indicators of river ecological health to adjust the function of environment purification and ecological buffer. The macroinvertebrates in the hyporheic zone are divided into three categories: stygoxenes, stygophiles and stygobites. The key factors which influenced macroinvertebrates distribution in the hyporheic zone are physical size of interstitial spaces, interstitial current velocity, dissolved oxygen (DO), water temperature, available organic matter, hydraulic conductivity and hydraulic retention time. A suitable sampling method should be used for diverse research purposes in the special ecological interface. In the future, some necessary researches should focus on the life-history and life history strategy of the macroinvertebrates in the hyporheic zone, the quantitative analysis on the matter and energy dynamics in the ecological system of stream, the assessment systems of river ecological health based on the macroinvertebrates of the stream hyporheic zone, and the ecological significance of the hyporheic zone as a refuge for distribution and evolution of the macroinvertebrates.

  11. Impact of contact lens zone geometry and ocular optics on bifocal retinal image quality.

    Science.gov (United States)

    Bradley, Arthur; Nam, Jayoung; Xu, Renfeng; Harman, Leslie; Thibos, Larry

    2014-05-01

    To examine the separate and combined influences of zone geometry, pupil size, diffraction, apodisation and spherical aberration on the optical performance of concentric zonal bifocals. Zonal bifocal pupil functions representing eye + ophthalmic correction were defined by interleaving wavefronts from separate optical zones of the bifocal. A two-zone design (a central circular inner zone surrounded by an annular outer-zone which is bounded by the pupil) and a five-zone design (a central small circular zone surrounded by four concentric annuli) were configured with programmable zone geometry, wavefront phase and pupil transmission characteristics. Using computational methods, we examined the effects of diffraction, Stiles Crawford apodisation, pupil size and spherical aberration on optical transfer functions for different target distances. Apodisation alters the relative weighting of each zone, and thus the balance of near and distance optical quality. When spherical aberration is included, the effective distance correction, add power and image quality depend on zone-geometry and Stiles Crawford Effect apodisation. When the outer zone width is narrow, diffraction limits the available image contrast when focused, but as pupil dilates and outer zone width increases, aberrations will limit the best achievable image quality. With two-zone designs, balancing near and distance image quality is not achieved with equal area inner and outer zones. With significant levels of spherical aberration, multi-zone designs effectively become multifocals. Wave optics and pupil varying ocular optics significantly affect the imaging capabilities of different optical zones of concentric bifocals. With two-zone bifocal designs, diffraction, pupil apodisation spherical aberration, and zone size influence both the effective add power and the pupil size required to balance near and distance image quality. Five-zone bifocal designs achieve a high degree of pupil size independence, and thus will

  12. Abundance, distribution and feeding patterns of a temperate reef fish in subtidal environments of the Chilean coast: the importance of understory algal turf Abundancia, distribución y patrones alimentarios de un pez de arrecifes templados en ambientes submareales de la costa de Chile: la importancia de la capa de algas del subdosel

    OpenAIRE

    Palma, Álvaro T.; F. PATRICIO OJEDA

    2002-01-01

    Cheilodactylus variegatus is an abundant carnivorous demersal reef fish that lives in the shallow subtidal of the north-central Chilean coast. Characteristically, these environments are dominated by kelp forests of Lessonia trabeculata. This species preys on a great variety of benthic invertebrates, and shows particularly high consumption rates on amphipod crustaceans. In our study, two widely separated populations of C. variegatus were considered (central and northern Chile). Individuals tha...

  13. Planktonic Subsidies to Surf-Zone and Intertidal Communities.

    Science.gov (United States)

    Morgan, Steven G; Shanks, Alan L; MacMahan, Jamie H; Reniers, Ad J H M; Feddersen, Falk

    2018-01-03

    Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones. These striking differences in subsidies have profound consequences; areas with greater subsidies support more productive surf-zone communities and possibly more productive rocky intertidal communities. Recognition of the importance of spatial subsidies for rocky community dynamics has recently advanced ecological theory, and incorporating surf-zone hydrodynamics would be an especially fruitful line of investigation.

  14. Zoning Districts - MDC_ROZABoundary

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — The boundaries of the ROZA are defined in Chapter 33 of the Zoning Code, Section 33-420, ARTICLE XLI. The area is known as the ROCK MINING OVERLAY ZONING AREA (ROZA)...

  15. Ecological zones of California deserts

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The dataset delineates ecological zones within California deserts. We derived ecological zones by reclassifying LANDFIRE vegetation biophysical setting types, plus...

  16. Parapapillary atrophy: histological gamma zone and delta zone.

    Directory of Open Access Journals (Sweden)

    Jost B Jonas

    Full Text Available BACKGROUND: To examine histomorphometrically the parapapillary region in human eyes. METHODOLOGY/PRINCIPAL FINDINGS: The histomorphometric study included 65 human globes (axial length:21-37 mm. On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME-optic nerve margin ("Gamma zone", BME-retinal pigment epithelium (RPE ("Beta zone", BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm was significantly (P = 0.01 larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28 associated with axial length. Beta zone was significantly (P = 0.004 larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm was associated with axial length (P50 µm diameter within gamma zone was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

  17. Competitive advantage for differentiation of Pereira International Free Trade Zone

    Directory of Open Access Journals (Sweden)

    Paola Andrea Echeverri Gutiérrez

    2014-01-01

    Full Text Available The best way to know if a company is at the heart of success is by determining its competitive advantage. For Pereira International Free Trade Zone, foreign trade platform and recent project implementation, it is important to identify its competitive advantage, so it can develop strategies for entering and staying in the market. In this research, an analysis of the five forces industry free zones was performed, the value chain of the Pereira International Free Trade Zone was defined, finally the factors that influence their competitive advantage was determined.

  18. Smartphones and Time Zones

    Science.gov (United States)

    Baird, William; Secrest, Jeffery; Padgett, Clifford; Johnson, Wayne; Hagrelius, Claire

    2016-09-01

    Using the Sun to tell time is an ancient idea, but we can take advantage of modern technology to bring it into the 21st century for students in astronomy, physics, or physical science classes. We have employed smartphones, Google Earth, and 3D printing to find the moment of local noon at two widely separated locations. By reviewing GPS time-stamped photos from each place, we are able to illustrate that local noon is longitude-dependent and therefore explain the need for time zones.

  19. Metallogeny of subduction zones

    Directory of Open Access Journals (Sweden)

    Sorokhtin N. O.

    2017-03-01

    Full Text Available The paper deals with the multistage mechanism of the Earth's crust enrichment in ore elements in underthrust zones. The processes of metamorphism and the formation of hydrothermal solutions at pulling of the watered oceanic lithospheric plate into the subduction zone have been described. Some physical and chemical transformation regularities of structural-material complexes in these areas and mechanisms of the formation of ore deposits have been discussed. Spatio-temporal patterns of the localization of a number of endogenetic and exogenetic deposits have been described using metallogeny of the Ural and the Verkhoyansk-Kolyma Fold Belts as an example. It has been shown that in nature there are several effective mechanisms of the enrichment of the crust in ore minerals. One of them is the process of pulling into subduction zone of metalliferous sediments and ferromanganese crusts as well as seabed nodules, their metamorphic transformation, partial melting and transition of ore components into magmatic melts and mineralized fluids. In the future this leads to the release of ore material by magmas and hydrothermal solutions into the folded formations of island-arc and Andean types and the formation of igneous, metasomatic and hydrothermal deposits. Another, yet no less powerful natural mechanism of a conveyor enrichment of the crust in ore elements is the process of destruction and sedimentation of mineral deposits formed in the folded areas as well as the formation of placers and their transfer to the marginal parts of the continent. Later, during the collision of active and passive margins of two lithospheric plates, such as the collision of the Kolyma Massif with the eastern part of the Siberian craton in the middle of the Mesozoic there was a thrusting of a younger lithospheric plate over a more ancient one. As a result, the sedimentary sequences of the passive margin of the Siberian plate were submerged and partially melted by the basic magmas

  20. [Current approach to zoning atomic shipbuilding plants].

    Science.gov (United States)

    Blekher, A Ia

    2005-01-01

    The paper discusses the currently introduced radiation-and-hygienic system for zoning atomic shipbuilding plants, in accordance with which three radiation-and-hygienic zones (a strict regime zone, a controlled approach zone, and a free regime zone) are established at the plant site and two zones (a sanitary-and-protective zone and a follow-up zone) are also established outside the plant site.

  1. The Near Zone to Far Zone Transformation (N2F)

    Energy Technology Data Exchange (ETDEWEB)

    Blackfield, Donald T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Poole, Brian R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-11

    N2F is a C/C++ code used to calculate the far zone electromagnetic (EM) field, given E and H near zone field data. The method used by N2F can be found in Ref. 1 and 2. N2F determines the far field EΦ and Eθ in spherical coordinates for near zone data calculated in either Cartesian or Cylindrical geometry.

  2. Empowerment Zones and Enterprise Districts - Volusia County Enterprise Zones

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Florida's Enterprise Zone Program encourages economic growth and investment in distressed areas by offering tax advantages and incentives to businesses that are...

  3. The influence of water and supercritical CO2 on the frictional strength and velocity dependence of montmorillonite and muscovite and the potential for fault zone reactivation in CO2 storage reservoirs

    Science.gov (United States)

    Samuelson, Jon

    2013-04-01

    Recent research indicates that CO2 is capable of inducing swelling in clay minerals in a similar fashion to water, though to a more modest extent. It is therefore of importance for feasibility studies of the geological storage of CO2 to understand if the addition of CO2 to clay rich fault zones has the potential to cause significant frictional weakening, similar to that associated with water. We conduct velocity-stepping direct shear experiments on pre-pressed plates (49 mm long x 35 mm wide x ~1 mm thick), of montmorillonite and muscovite. An effective normal stress of 35 MPa is used in all experiments, which is roughly equivalent to the effective overburden stress expected in many storage projects. Temperature was held constant at ~48 °C, consistent with previous experiments which indicated CO2 induced swelling in montmorillonite. Pore fluid conditions are the main variable in this suite of experiments, in which the frictional strength of each clay mineral is analyzed oven-dry (attached to vacuum), saturated with deionized (DI) water, and oven-dry saturated with supercritical CO2. Pore pressure is maintained at 15 MPa for the water and CO2 saturated experiments (?n=50 MPa, PH20-CO2=15 MPa). Shearing velocity is varied systematically from approximately 11 μm/s to 0.2, 1.1, 11, 1.1, and 0.2 μm/s in order to determine the rate and state friction parameters, a, b, and DC. Additionally, microstructural analysis of the post-shear clay gouges is conducted in an effort to understand the rheology behind changes observed in frictional properties. Preliminary results of experiments on montmorillonite show an overconsolidation peak at strains of approximately 0.3 for each of the oven-dry and water and CO2 saturated experiments. Peak friction (μP) for oven-dry montmorillonite is 0.53, decaying to a steady state friction (μSS) of 0.51. For DI-saturated montmorillonite μP=0.11 and μSS=0.10. CO2-saturated montmorillonite displays frictional strength between that of dry

  4. Navigating ECA-Zones

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Grønsedt, Peter; Hendriksen, Christian

    is the substantial impact of the current and future oil price on the optimal compliance strategies ship-owners choose when complying with the new air emission requirements for vessels. The oil price determines the attractiveness of investing in asset modification for compliance, given the capital investment required....... Operating on low-Sulphur fuels remains favourable with a low oil price, as the price spread between high- and low-Sulphur does not outweigh the price of asset investments. Ship-owners who are contemplating future compliance strategies should monitor the developments of the global oil price, and consider how......This report examines the effect that ECA-zone regulation has on the optimal vessel fuel strategies for compliance. The findings of this report are trifold, and this report is coupled with a calculation tool which is released to assist ship-owners in the ECA decision making. The first key insight...

  5. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  6. The influence of air-sea-ice interactions on an anomalous phytoplankton bloom in the Indian Ocean sector of the Antarctic Zone of the Southern Ocean during the austral summer, 2011

    Science.gov (United States)

    Sabu, P.; Anilkumar, N.; George, Jenson V.; Chacko, Racheal; Tripathy, S. C.; Achuthankutty, C. T.

    2014-12-01

    An anomalous phytoplankton bloom was recorded in the Indian Ocean sector of the Antarctic Zone (AZ) of the Southern Ocean (SO) during the austral summer, 2011. Possible mechanisms for the triggering of such a large bloom were analyzed with the help of in situ and satellite data. The bloom, which formed in January 2011, intensified during February and weakened by March. High surface chlorophyll (Chl) concentrations (0.76 mg m-3) were observed in the area of the bloom (60°S, 47°E) with a Deep Chlorophyll Maximum (DCM) of 1.15 mg m-3 at a depth of 40-60 m. During 2011, both the concentration and spatial extent of sea ice were high on the western side of the bloom, between 0°E and 40°E, and enhanced freshwater influx was observed in the study area as a result of melting ice. A positive Southern Annular Mode (SAM) (with a resultant northward horizontal advection) and an intense La Niña during 2010-2011 are possible reasons for the high sea-ice concentrations. The enhanced Chl a observed in the study region, which can be attributed to the phytoplankton bloom, likely resulted from the influx of nutrient-laden freshwater derived from melting sea ice.

  7. Work Zone Data Collection Trailer

    Data.gov (United States)

    Federal Laboratory Consortium — The Work Zone Data Collection Trailer was designed and constructed to enhance data collection and analysis capabilities for the "Evaluating Roadway Construction Work...

  8. Variación espacio-temporal de la meiofauna submareal en una playa arenosa nororiental de Venezuela Spatio-temporal variation of subtidal meiofauna in a sandy beach from Northeastern Venezuela

    Directory of Open Access Journals (Sweden)

    Ildefonso Liñero Arana

    2013-03-01

    Full Text Available La meiofauna incluye metazoos y foraminíferos bénticos que pasan a través de un tamiz de 500mm y son retenidos en malla de 40-63μm. Se estudió la variación espacial y temporal de la meiofauna en cuatro estaciones submareales a 1m de profundidad, de una playa arenosa situada en la costa nororiental de Venezuela. Mensualmente, durante un año, en cada estación, con un nucleador de 2.5cm de diámetro interno, se tomaron tres réplicas de sedimento hasta 10cm de profundidad y se pasaron a través de un tamiz de 0.063mm de abertura de malla. Se identificaron 14 grupos meiofaunales, excluidos los foraminíferos, siendo los nemátodos, ostrácodos y copépodos harpacticoides los más abundantes. La densidad mensual estuvo comprendida entre 64 y 503ind./10cm², y la densidad media en las estaciones entre 173 y 449ind./10cm². La densidad de la meiofauna en la playa San Luis es baja en comparación con otros estudios realizados en zonas tropicales. En esta playa el control de las comunidades meiofaunísticas es compartido por las condiciones climáticas y la biología de las especies.Meiofauna organisms that play an important role in the trophic ecology of soft bottom benthos, have short life cycles and they respond quickly to disturbance and pollution. The present study shows the spatio-temporal variation of subtidal meiofauna (metazoans passing a 500μm sieve but retained on meshes of 40-63μm in four shallow subtidal stations. Samples were taken in the sandy beach of San Luis, in the Northeastern coast of Venezuela, from October 2005 until September 2006. For this, three replicate sediment core samples (4.91cm², were collected monthly to a depth of 10cm into the sediment, and preserved in 6% formalin stained with rose Bengal. Specimens of 14 meiofaunal groups (Foraminifera excluded were collected, being the nematodes, ostracods and harpacticoid copepods the most abundant. Monthly density was comprised between 64 and 503ind./10cm², and mean

  9. Vacant Nests and Other Factors Influencing Nest Site Selection of Birds of Prey Based on Case Studies in Forest Habitats in the Forest-Steppe and Steppe Zones of Eastern Ukraine

    Directory of Open Access Journals (Sweden)

    Stanislav G. Viter

    2015-12-01

    Full Text Available Our study was conducted in 2003–2012 in Eastern Ukraine, in the basin of the Seversky Donets river. The total surveyed area was ca. 900 km2 of nesting habitats suitable for raptors. A total of 69 vacant nests were found, i.e. 33.2 % of the total number of nests (208. Nests occupied by recipient species, i.e. the so-called ‘effective nest pool’, were 23–24, i.e. 33.3–34.7 % of the pool of available nests. Up to 25 % of all pairs of raptors depend on the availability of vacant nests of heterospecifics. Ravens (Corvus corax are the most significant donors of nests: 42.5 % of the pool of available nests is built by this species, and more than 60 % of them are occupied by recipient species. Common Buzzard (Buteo buteo comes second with 26.09 and 58.3 %, respectively. The most common recipients of nests are Hobbies (Falco subbuteo, Common Kestrel (Falco tinnunculus and Booted Eagles (Hieraaetus pennatus. The most significant factors that govern occupation of vacant nests by recipient species are: availability of nests in the marginal zone of forest plots, i.e. within 500 m from the forest edge, large distance from human settlements (>1500 m, presence of nests located on trees in the canopy storey, and mature and submature age of forest stands. For seven species considered in our research (n=227, the most important factors were position of nests, in the forest canopy layer, no logging activity within300 m of the nest, no regular human disturbance, and presence of “windows” in the canopy made by fallen trees.

  10. Habitat coupling writ large: pelagic-derived materials fuel benthivorous macroalgal reef fishes in an upwelling zone.

    Science.gov (United States)

    Docmac, Felipe; Araya, Miguel; Hinojosa, Ivan A; Dorador, Cristina; Harrod, Chris

    2017-09-01

    Coastal marine upwelling famously supports elevated levels of pelagic biological production, but can also subsidize production in inshore habitats via pelagic-benthic coupling. Consumers inhabiting macroalgae-dominated rocky reef habitats are often considered to be members of a food web fuelled by energy derived from benthic primary production; conversely, they may also be subsidized by materials transported from pelagic habitats. Here, we used stable isotopes (δ 13 C, δ 15 N) to examine the relative contribution of pelagic and benthic materials to an ecologically and economically important benthivorous fish assemblage inhabiting subtidal macroalgae-dominated reefs along ~1,000 km of the northern Chilean coast where coastal upwelling is active. Fish were isotopically most similar to the pelagic pathway and Bayesian mixing models indicated that production of benthivorous fish was dominated (median 98%, range 69-99%) by pelagic-derived C and N. Although the mechanism by which these materials enter the benthic food web remains unknown, our results clearly highlight the importance of pelagic-benthic coupling in the region. The scale of this subsidy has substantial implications for our basic understanding of ecosystem functioning and the management of nearshore habitats in northern Chile and other upwelling zones worldwide. © 2017 by the Ecological Society of America.

  11. Accommodation space, relative sea level, and the archiving of paleo-earthquakes along subduction zones

    Science.gov (United States)

    Kelsey, Harvey M.; Engelhart, Simon E.; Pilarczyk, Jessica E.; Horton, Benjamin P.; Rubin, Charles; Daryono, Mudrik; Ismail, Nazli; Hawkes, Andrea D.; Bernhardt, Christopher E.; Cahill, Niamh

    2015-01-01

    The spatial variability of Holocene relative sea-level (RSL) change influences the capacities of coastal environments to accommodate a sedimentary record of paleoenvironmental change. In this study we couch a specific investigation in more general terms in order to demonstrate the applicability of the relative sea-level history approach to paleoseismic investigations. Using subsidence stratigraphy, we trace the different modes of coastal sedimentation over the course of time in the eastern Indian Ocean where RSL change evolved from rapidly rising to static from 8000 yr ago to present. Initially, the coastal sites from the Aceh, Sumatra, coastal plain, which are subject to repeated great earthquakes and tsunamis, built up a sedimentary sequence in response to a RSL rise of 1.4 mm/yr. The sequence found at 2 sites 8 km apart contained 3 soils of a mangrove origin (Rhizophora,Bruguiera/Ceriops, Avicennia pollen, and/or intertidal foraminifera) buried by sudden submergence related to coseismic subsidence and 6 tsunami sands that contain pristine subtidal and planktic foraminifera. After 3800 cal yr B.P. (years before A.D. 1950), sea level stabilized and remained such to the present. The stable relative sea level reduced accommodation space in the late Holocene, suggesting that the continued aggradation of the coastal plain was a consequence of periodic coastal inundation by tsunamis.

  12. Zone refining of plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Michael S. [Univ. of Idaho, Moscow, ID (United States)

    1994-08-01

    The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elements Al, Am, and Ga moved in the opposite direction of the molten zone as predicted by binary phase diagrams. As the impurity alloy was zone refined, {delta}-phase plutonium metal crystals were produced. The first few zone refining passes were more effective than each later pass because an oxide layer formed on the rod surface. There was no clear evidence of better impurity movement at the slower zone refining speed. Also, constant or variable coil power appeared to have no effect on impurity movement during a single run (10 passes). This experiment was the first step to developing a zone refining process for plutonium metal.

  13. Achieving That Elusive "Leadership Zone"

    Science.gov (United States)

    Martin, Ann M.

    2016-01-01

    Reaching the "leadership zone" happens when librarians tap into the extraordinary skills lying within to overcome obstacles and transform sometimes-difficult situations into meaningful outcomes. Maturing into an experienced leader who stays in the leadership zone requires knowledge, training, and practice. This article provides tactical…

  14. Instrumentation for coastal zone management

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    stream_size 11 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_91.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_91.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  15. Management of coastal zone vegetation

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.

    stream_size 14 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_22.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_22.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  16. The Development Evaluation of Economic Zones in China.

    Science.gov (United States)

    Liu, Wei; Shi, Hong-Bo; Zhang, Zhe; Tsai, Sang-Bing; Zhai, Yuming; Chen, Quan; Wang, Jiangtao

    2018-01-02

    After the Chinese reform and opening up, the construction of economic zones, such as Special Economic Zones, Hi-tech Zones and Bonded Zones, has played an irreplaceable role in China's economic development. Currently, against the background of Chinese economic transition, research on development evaluation of economic zones has become popular and necessary. Similar research usually focuses on one specific field, and the methods that are used to evaluate it are simple. This research aims to analyse the development evaluation of zones by synthesis. A new hybrid multiple criteria decision making (MCDM) model that combines the DEMATEL technique and the DANP method is proposed. After establishing the evaluation criterion system and acquiring data, the influential weights of dimensions and criteria can be calculated, which will be a guide for forming measures of development. Shandong Peninsula Blue Economic Zone is used in the empirical case analysis. The results show that Transportation Conditions, Industrial Structure and Business Climate are the main influencing criteria and measures based on these criteria are proposed.

  17. A density-based clustering algorithm for earthquake zoning

    Science.gov (United States)

    Scitovski, Sanja

    2018-01-01

    A possibility of applying the density-based clustering algorithm Rough-DBSCAN for earthquake zoning is considered in the paper. By using density-based clustering for earthquake zoning it is possible to recognize nonconvex shapes, what gives much more realistic results. Special attention is thereby paid to the problem of determining the corresponding value of the parameter ɛ in the algorithm. The size of the parameter ɛ significantly influences the recognizing number and configuration of earthquake zones. A method for selecting the parameter ɛ in the case of big data is also proposed. The method is applied to the problem of earthquake data zoning in a wider area of the Republic of Croatia.

  18. Bending zone from mobilistic positions

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrijevic, M.D.

    1983-01-01

    Between the carbonate platform of Dinarid and the region of development of the diabase-hornfels formation (to the north and northeast), a transitional zone is observed with specific geological characteristics. It is called the ''bending zone'' and is viewed as an intermediate zone between the eugeosynclinal and myogeosynclinal regions and is the slope of the carbonate platform which is turned towards the region of Mesozoic magmatism. From the mobilistic viewpoint of geotectonics, it can be considered the boundary of the Adriatic microplate and the Tetis Sea. The geological position of the zone and the time of its existence (Triassic, Jurassic and later; ratio of it to the Senoman blend remains obscure) are examined. The zone is not considered to be very promising from an oil geological viewpoint.

  19. The Supergalactic Habitable Zone

    Science.gov (United States)

    Mason, Paul

    2018-01-01

    Habitability in the local universe is examined. Constrained by metal abundance and exposure to sterilizing events, life as we know it requires significantly long periods of stable environmental conditions. Planets within galaxies undergoing major mergers, active AGN, starburst episodes, and merging black holes pose serious threats to long-term habitability. Importantly, the development of several layers of protection from high-energy particles such as a thick atmosphere, a strong planetary magnetic field, an astrosphere, and a galactic magnetic field is of great benefit. Factors such as star type and activity, planet type and composition, the location of a planet within its host galaxy, and even the location within a supercluster of galaxies can affect the potential habitability of planets. We discuss the concept of the Supergalactic Habitable Zone introduced by Mason and Biermann in terms of habitability in the local universe and find that galaxies near the center of the Virgo cluster, for example, have a much lower probability for the development of life as we know it as compared to locations in the Milky Way.

  20. 49 CFR 71.14 - Chamorro Zone.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Chamorro Zone. 71.14 Section 71.14 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.14 Chamorro Zone. The ninth zone, the Chamorro standard time zone, includes the Island of Guam and the Commonwealth of the Northern...

  1. The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat.

    Directory of Open Access Journals (Sweden)

    DelWayne R Bohnenstiehl

    Full Text Available Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500-2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71-0.92 and vary seasonally by ~15 decibels in the 1.5-20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81-0.93, as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5-10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal

  2. Nutrient cycling in bedform induced hyporheic zones

    Science.gov (United States)

    Bardini, L.; Boano, F.; Cardenas, M. B.; Revelli, R.; Ridolfi, L.

    2012-05-01

    The hyporheic zone is an ecotone connecting the stream and groundwater ecosystem that plays a significant role for stream biogeochemistry. Water exchange across the stream-sediment interface and biogeochemical reactions in the streambed concur to affect subsurface solute concentrations and eventually nutrient cycling in the fluvial corridor. In this paper we investigate the interplay of hydrological and biogeochemical processes in a duned streambed and their effect on spatial distribution of solutes. We employ a numerical model to simulate the turbulent water flow and the pressure distribution over the dunes, and then to evaluate the flow field and the biogeochemical reactions in the hyporheic sediments. Sensitivity analyses are performed to analyze the influence of hydrological and chemical properties of the system on solute reaction rates. The results demonstrate the effect of stream velocity and sediment permeability on the chemical zonation. Changing sediment permeability as well as stream velocity directly affects the nutrient supply and the residence times in the streambed, thus controlling the reaction rates under the dune. Stream-water quality is also shown to influence the reactive behavior of the sediments. In particular, the availability of dissolved organic carbon determines whether the streambed acts as a net sink or source of nitrate. This study represents a step towards a better understanding of the complex interactions between hydrodynamical and biogeochemical processes in the hyporheic zone.

  3. Winter Storm Zones on Mars

    Science.gov (United States)

    Hollingsworth, J. L.; Haberle, R. M.; Barnes, J. R.; Bridger, A. F. C.; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    Preferred regions of weather activity in Mars' winter middle latitudes-so called 'storm zones' are found in a general circulation model of Mars' atmospheric circulation. During northern winter, these storm zones occur in middle latitudes in the major planitia (low-relief regions) of the western and eastern hemisphere. In contrast, the highlands of the eastern hemisphere are mostly quiescent. Compared to Earth's storm zones where diabatic heating associated with land-sea thermal contrasts is crucial, orography on Mars is fundamental to the regionalization of weather activity. Future spacecraft missions aimed at assessing Mars' climate and its variability need to include such regions in observation strategies.

  4. Industrial Free Zones in the Dominican Republic: National vs. Local Impact.

    Science.gov (United States)

    Sagawe, Thorsten

    1996-01-01

    Provides a concise overview on export-based, free zone development in the Dominican Republic by examining its influence on three spatial levels: national, regional, and town. Although industrial free zones contribute to job creation and foreign exchange earnings, local authorities are often unable to control urban development. (MJP)

  5. ShoreZone Survey Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a point file showing GPS trackline data collected during a ShoreZone aerial imaging survey. This flight trackline is recorded at 1-second intervals...

  6. NEPR Geographic Zone Map 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geographic zone map was created by interpreting satellite and aerial imagery, seafloor topography (bathymetry model), and the new NEPR Benthic Habitat Map...

  7. Offshore Wind Technology Depth Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coastal bathymetric depth, measured in meters at depth values of: -30, -60, -900 Shallow Zone (0-30m): Technology has been demonstrated on a commercial scale at...

  8. Embodied Archives as Contact Zones

    OpenAIRE

    Judit Vidiella

    2015-01-01

    This article proposes a reflection about affective politics from locating some theoretical and conceptual genealogies like «emotion», «affection», «zones of contact»…, that understand them as action and force fields. These contributions allow us to rethink the relation of affects with politics and strategies of archive linked to performance, and understood as zones of friction, collision, circulation and contact: performative writing, repertoire, memes…

  9. Embodied Archives as Contact Zones

    Directory of Open Access Journals (Sweden)

    Judit Vidiella

    2015-02-01

    Full Text Available This article proposes a reflection about affective politics from locating some theoretical and conceptual genealogies like «emotion», «affection», «zones of contact»…, that understand them as action and force fields. These contributions allow us to rethink the relation of affects with politics and strategies of archive linked to performance, and understood as zones of friction, collision, circulation and contact: performative writing, repertoire, memes…

  10. Climate change and dead zones.

    Science.gov (United States)

    Altieri, Andrew H; Gedan, Keryn B

    2015-04-01

    Estuaries and coastal seas provide valuable ecosystem services but are particularly vulnerable to the co-occurring threats of climate change and oxygen-depleted dead zones. We analyzed the severity of climate change predicted for existing dead zones, and found that 94% of dead zones are in regions that will experience at least a 2 °C temperature increase by the end of the century. We then reviewed how climate change will exacerbate hypoxic conditions through oceanographic, ecological, and physiological processes. We found evidence that suggests numerous climate variables including temperature, ocean acidification, sea-level rise, precipitation, wind, and storm patterns will affect dead zones, and that each of those factors has the potential to act through multiple pathways on both oxygen availability and ecological responses to hypoxia. Given the variety and strength of the mechanisms by which climate change exacerbates hypoxia, and the rates at which climate is changing, we posit that climate change variables are contributing to the dead zone epidemic by acting synergistically with one another and with recognized anthropogenic triggers of hypoxia including eutrophication. This suggests that a multidisciplinary, integrated approach that considers the full range of climate variables is needed to track and potentially reverse the spread of dead zones. © 2014 John Wiley & Sons Ltd.

  11. Earthquakes in the Pamplona zone, Yakutat block, south central Alaska

    Science.gov (United States)

    Doser, Diane I.; Pelton, John R.; Veilleux, Annette M.

    1997-11-01

    The Pamplona zone is a region of complex deformation and moderate seismicity located within the Yakutat block, a region that has been relatively aseismic since a series of large (M>7.8) earthquakes in 1899. In 1970 a sequence of moderate to large sized earthquakes occurred within the Pamplona zone (largest event of Mw=6.7). Together with a Mw=6.1 event in 1958, these events are the only M≥5.5 events known to have occurred in the Pamplona region since 1900. Thus these events give important information on internal deformational processes within the Yakutat block. Waveform modeling of three earthquakes in April 1970, showed rupture complexity along low angle, thrust faults. Focal depths indicate that two of the events occurred above the Wrangell-Aleutian megathrust, while the largest event may have occurred on the megathrust. Events in 1958 and February 1970 indicate that deformation within the western Pamplona zone is occurring along high angle (>60°) faults with reverse-oblique motion. We believe the Pamplona spur, the easternmost part of the Pamplona zone, may have behaved as an asperity during the 1899 sequence. The location of the spur may be influenced by a north-south trending fault zone in the subducting Pacific plate that appears to be responsible for the 1987-1992 Gulf of Alaska sequence, occurring 50 to 200 km south of the Pamplona zone.

  12. The global aftershock zone

    Science.gov (United States)

    Parsons, Thomas E.; Margaret Segou,; Warner Marzocchi,

    2014-01-01

    The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often superposed onto already seismically active regions, making them difficult to detect and understand. From a hazard perspective we are concerned that this dynamic process might encourage other high magnitude earthquakes, and wonder if a global alarm state is warranted after every large mainshock. From an earthquake process perspective we are curious about the physics of earthquake triggering across the magnitude spectrum. In this review we build upon past studies that examined the combined global response to mainshocks. Such compilations demonstrate significant rate increases during, and immediately after (~ 45 min) M > 7.0 mainshocks in all tectonic settings and ranges. However, it is difficult to find strong evidence for M > 5 rate increases during the passage of surface waves in combined global catalogs. On the other hand, recently published studies of individual large mainshocks associate M > 5 triggering at global range that is delayed by hours to days after surface wave arrivals. The longer the delay between mainshock and global aftershock, the more difficult it is to establish causation. To address these questions, we review the response to 260 M ≥ 7.0 shallow (Z ≤ 50 km) mainshocks in 21 global regions with local seismograph networks. In this way we can examine the detailed temporal and spatial response, or lack thereof, during passing seismic waves, and over the 24 h period after their passing. We see an array of responses that can involve immediate and widespread seismicity outbreaks, delayed and localized earthquake clusters, to no response at all. About 50% of the

  13. Review of unsaturated-zone transport and attenuation of volatile organic compound (VOC) plumes leached from shallow source zones

    Science.gov (United States)

    Rivett, Michael O.; Wealthall, Gary P.; Dearden, Rachel A.; McAlary, Todd A.

    2011-04-01

    provide good opportunity for further sensitivity analysis and development to practitioner use. There remains a significant need to obtain intermediate laboratory-scale and particularly field-scale (actual site and controlled release) datasets that address the scenario as a whole and permit validation of the available models. Integrated assessment of the range of simultaneous processes that combine to influence leached plume generation, transport and attenuation in the unsaturated zone is required. Component process research needs are required across the problem scenario and include: the simultaneous volatilisation and dissolution of source zones; development of appropriate field-scale dispersion estimates for the unsaturated zone; assessment of transient VOC exchanges between aqueous, vapour and sorbed phases and their influence upon plume attenuation; development of improved field methods to recognise and quantify biodegradation of CAHs; establishment of the influence of co-contaminants; and, finally, translation of research findings into more robust practitioner practice.

  14. Changes of hydrological environment and their influences on coastal wetlands in the southern Laizhou Bay, China.

    Science.gov (United States)

    Zhang, Xuliang; Zhang, Yuanzhi; Sun, Hongxia; Xia, Dongxing

    2006-08-01

    The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore "red tides" happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area.

  15. Marginal Ice Zone Flux and Variability

    Science.gov (United States)

    Pfirman, S. L.; Tremblay, B.; Newton, R.; Fowler, C.

    2009-12-01

    Arctic sea ice acts as a conveyor, collecting and transporting material across the central basin, and releasing it in the marginal ice zone (MIZ). Where and when ice with different transport histories melts, has a large impact on the MIZ and is critical for understanding the vulnerability of the Arctic system to climate change. This study focuses on the effects of changing the location and timing of fluxes to the MIZ, as well as the age and origin of ice delivered there. Combining observations and models, we analyze sea ice motion for origin, age, drift path, and flux (both along the drift path and to the MIZ) for past, recent, and future scenarios. We examine temporal and spatial variations in the transport of sea ice and ice-rafted material between different source and melt regions for interannual and seasonal variability, including: a) How the distribution, origin, and age of ice delivered to various MIZs has changed over time, especially during the spring bloom. b) How changes in ice drift related to changes in atmospheric, oceanic, sedimentologic, and ecologic conditions have influenced the delivery of freshwater, sediments, and biological material. c) How changes have varied regionally and with respect to water depth. For example, whether maximum ice melt - and therefore material release - occurs over deep waters or shallow shelves is an important ecological parameter. As the Arctic transitions toward ice free summer conditions, the seasonal ice zone will expand, shifting the location of the marginal ice zone. It is critical to understand processes governing these changes because the MIZ is the most dynamic, most productive, and most vulnerable region in the Arctic.

  16. Galactic Habitable Zone and Astrobiological Complexity

    Science.gov (United States)

    Vukotic, B.

    2012-12-01

    This is a short thesis description and for the sake of brevity most things are left out. For more details, those interested are further directed to the thesis related papers in this article reference list. Thesis itself is available at the University of Belgrade library "Svetozar Markovic" (Serbian version only). In this thesis we study the astrobiological history of the Galactic habitable zone through the means of numerical modeling. First group of simulations are unidimensional (time-axis) toy models examine the influence of global regulation mechanisms (gamma-ray bursts and supernovae) on temporal evolution of Galactic astrobiological complexity. It is shown that under the assumption of global regulation classical anti SETI arguments can be undermined. Second group of simulations are more complex bidimensional probabilistic cellular automata models of the Galactic thin disk. They confirm the findings of the toy models and give some insights into the spatial clustering of astrobiological complexity. As a new emerging multidisciplinary science the basic concepts of astrobiology are poorly understood and although all the simulations present here do not include some basic physics (such as Galactic kinematics and dynamics), the input parameters are somewhat arbitrary and could use a future refinement (such as the boundaries of the Galactic habitable zone). This is the cause for low weight and high uncertainty in the output results of the simulations. However, the probabilistic cellular automata has shown as a highly adaptable modeling platform that can simulate various class of astrobiological models with great ease.

  17. The Root Apex of Arabidopsis thaliana Consists of Four Distinct Zones of Growth Activities: Meristematic Zone, Transition Zone, Fast Elongation Zone and Growth Terminating Zone.

    Science.gov (United States)

    Verbelen, Jean-Pierre; De Cnodder, Tinne; Le, Jie; Vissenberg, Kris; Baluska, Frantisek

    2006-11-01

    In the growing apex of Arabidopsis thaliana primary roots, cells proceed through four distinct phases of cellular activities. These zones and their boundaries can be well defined based on their characteristic cellular activities. The meristematic zone comprises, and is limited to, all cells that undergo mitotic divisions. Detailed in vivo analysis of transgenic lines reveals that, in the Columbia-0 ecotype, the meristem stretches up to 200 microm away from the junction between root and root cap (RCJ). In the transition zone, 200 to about 520 microm away from the RCJ, cells undergo physiological changes as they prepare for their fast elongation. Upon entering the transition zone, they progressively develop a central vacuole, polarize the cytoskeleton and remodel their cell walls. Cells grow slowly during this transition: it takes ten hours to triplicate cell length from 8.5 to about 35 microm in the trichoblast cell files. In the fast elongation zone, which covers the zone from 520 to about 850 microm from the RCJ, cell length quadruplicates to about 140 microm in only two hours. This is accompanied by drastic and specific cell wall alterations. Finally, root hairs fully develop in the growth terminating zone, where root cells undergo a minor elongation to reach their mature lengths.

  18. Methods for converting industrial zones

    Science.gov (United States)

    Talipova, L.; Kosyakov, E.; Polyakova, Irina

    2017-10-01

    In this article, industrial zones of Saint Petersburg and Hong Kong were considered. Competitive projects aimed at developing the grey belt of Saint Petersburg were considered. The methodology of the survey of reconstruction of the industrial zone of Hong Kong is also analyzed. The potential of the city’s grey belt lies in its location on the border of the city’s historical centre. Rational use of this potential will make it possible to achieve numerous objectives, including development of the city’s transport infrastructure, positioning of business functions, and organization of housing and the city’s system of green public spaces.

  19. Seismotectonic zoning of Azerbaijan territory

    Science.gov (United States)

    Kangarli, Talat; Aliyev, Ali; Aliyev, Fuad; Rahimov, Fuad

    2017-04-01

    Studying of the space-time correlation and consequences effect between tectonic events and other geological processes that have created modern earth structure still remains as one of the most important problems in geology. This problem is especially important for the East Caucasus-South Caspian geodynamic zone. Being situated at the eastern part of the Caucasian strait, this zone refers to a center of Alpine-Himalayan active folded belt, and is known as a complex tectonic unit with jointing heterogeneous structural-substantial complexes arising from different branches of the belt (Doburja-Caucasus-Kopetdag from the north and Pyrenean-Alborz from the south with Kura and South Caspian zone). According to GPS and precise leveling data, activity of regional geodynamic processes shows intensive horizontal and vertical movements of the Earth's crust as conditioned by collision of the Arabian and Eurasian continental plates continuing since the end of Miocene. So far studies related to the regional of geology-geophysical data, periodically used for the geological and tectonic modeling of the environment mainly based on the fixing ideology. There still remains a number of uncertainties in solution of issues related to regional geology, tectonics and magmatism, structure and interrelation of different structural zones, space-time interrelations between onshore and offshore complexes, etc. At the same time large dataset produced by surface geological surveys, deep geological mapping of on- and offshore areas with the use of seismic and electrical reconnaissance and geophysical field zoning methods, deep well drilling and remote sensing activities. Conducted new studies produced results including differentiation of formerly unknown nappe complexes of the different ages and scales within the structure of mountain-fold zones, identification of new zones containing ophiolites in their section, outlining of currently active faulting areas, geophysical interpretation of the deep

  20. Zone refining of plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The purpose of this study was to investigate zone refining techniques for the purification of plutonium metal. The redistribution of 10 impurity elements from zone melting was examined. Four tantalum boats were loaded with plutonium impurity alloy, placed in a vacuum furnace, heated to 700{degrees}C, and held at temperature for one hour. Ten passes were made with each boat. Metallographic and chemical analyses performed on the plutonium rods showed that, after 10 passes, moderate movement of certain elements were achieved. Molten zone speeds of 1 or 2 inches per hour had no effect on impurity element movement. Likewise, the application of constant or variable power had no effect on impurity movement. The study implies that development of a zone refining process to purify plutonium is feasible. Development of a process will be hampered by two factors: (1) the effect on impurity element redistribution of the oxide layer formed on the exposed surface of the material is not understood, and (2) the tantalum container material is not inert in the presence of plutonium. Cold boat studies are planned, with higher temperature and vacuum levels, to determine the effect on these factors. 5 refs., 1 tab., 5 figs.

  1. ShoreZone Mapped Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is a polyline file of mapped ShoreZone units which correspond with data records found in the Unit, Xshr, BioUnit, and BioBand tables of this...

  2. Building a Subduction Zone Observatory

    Science.gov (United States)

    Gomberg, Joan S.; Bodin, Paul; Bourgeois, Jody; Cashman, Susan; Cowan, Darrel; Creager, Kenneth C.; Crowell, Brendan; Duvall, Alison; Frankel, Arthur; Gonzalez, Frank; Houston, Heidi; Johnson, Paul; Kelsey, Harvey; Miller, Una; Roland, Emily C.; Schmidt, David; Staisch, Lydia; Vidale, John; Wilcock, William; Wirth, Erin

    2016-01-01

    Subduction zones contain many of Earth’s most remarkable geologic structures, from the deepest oceanic trenches to glacier-covered mountains and steaming volcanoes. These environments formed through spectacular events: Nature’s largest earthquakes, tsunamis, and volcanic eruptions are born here.

  3. Deciduous Forest Zone of Ghana

    African Journals Online (AJOL)

    Drainage becomes poorer towards the valley bottom, where soils gener- ally show loamy textures and redoximorphic features, but only Oda shows high base saturation and pH(CaCl). (5.8-5.9) throughout the profile. Key words: Catena, soil series, pedology, forest, soil. Introduction. The semi-deciduous forest Zone of Ghana.

  4. Objects as Temporary Autonomous Zones

    Directory of Open Access Journals (Sweden)

    Tim Morton

    2011-09-01

    Full Text Available From Hakim Bey's instructions on creating temporary autonomous zones we see an oscillation "between performance art and politics, circus clowning and revolution." In this essay Tim Morton discusses anarchist politics as, "the creation of fresh objects in a reality without a top or a bottom object, or for that matter a middle object."

  5. ISOLDE target zone control room

    CERN Multimedia

    2016-01-01

    Operating the ISOLDE target handling robots from the dedicated control room in building 197. Monitors showing the movements of the robots (GPS in this case) in the target zone. The footage shows the actual operation by the operator as well as the different equipment such as camera electronics, camera motor controls, camera monitors and Kuka robot controls touch panel.

  6. Oceanic fronts: transition zones for bacterioplankton community composition

    Science.gov (United States)

    Baltar, F.; Currie, K.; Stuck, E.; Roosa, S.; Morales, S.

    2016-02-01

    Oceanic fronts are widespread mesoscale features that exist in the boundary between different water masses. Bacterioplankton (including Bacteria and Archaea) drive oceanic biogeochemical cycles, regulating the composition of Earth's atmosphere and influencing climate. Despite the recognized importance of bacterioplankton on the marine biogeochemical cycles and the ubiquitousness of fronts, the effect of frontal zones on the distribution of bacterioplankton community remains unknown. Using 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses, we demonstrate strong shifts in bacterioplankton community composition (BCC) across the Subtropical Frontal Zone off New Zealand. Transition between water masses resulted in a clear modification of the dominant taxa and a significant increase in community dissimilarity. Our results, linking physical oceanography and marine molecular ecology, support the strong role of oceanic frontal zones in delimiting the distribution of bacterioplankton in the ocean, where fronts serve as clear transition zones, indicating boundaries for bacterioplankton distribution in the ocean. Owing to the widespread abundance of fronts in the marine environment, future efforts should focus on confirming their roles in demarking bacterioplankton distribution and whether they act as indicators of ecosystem process changes. This would allow a better understanding of the forces that control energy flow in the ocean as well as the cycling of compounds that influence climate change, and concomitantly building more accurate models of global biogeochemical cycles.

  7. Fifty years of shear zones

    Science.gov (United States)

    Graham, Rodney

    2017-04-01

    We are here, of course, because 1967 saw the publication of John Ramsay's famous book. Two years later a memorable field trip from Imperial College to the Outer Hebrides saw John on a bleak headland on the coast of North Uist where a relatively undeformed metadolerite within Lewisian (Precambrian) gneisses contained ductile shear zones with metamorphic fabrics in amphibolite facies. One particular outcrop was very special - a shear zone cutting otherwise completely isotropic, undeformed metadolerite, with an incremental foliation starting to develop at 45° to the deformation zone, and increasing in intensity as it approached the shear direction. Here was proof of the process of simple shear under ductile metamorphic conditions - the principles of simple shear outlined in John Ramsay's 1967 book clearly visible in nature, and verified by Ramsay's mathematical proofs in the eventual paper (Ramsay and Graham, 1970). Later work on the Lewisian on the mainland of Scotland, in South Harris, in Africa, and elsewhere applied Ramsay's simple shear principles more liberally, more imprecisely and on larger scale than at Caisteal Odair, but in retrospect it documented what seems now to be the generality of mid and lower crustal deformation. Deep seismic reflection data show us that on passive margins hyper-stretched continental crust (whether or not cloaked by Seaward Dipping Reflectors) seems to have collapsed onto the mantle. Crustal faults mostly sole out at or above the mantle - so the Moho is a detachment- an 'outer marginal detachment', if you like, and, of course, it must be a ductile shear. On non-volcanic margins this shear zone forms the first formed ocean floor before true sea floor spreading gets going to create real oceanic crust. Gianreto Manatschal, Marcel Lemoine and others realised that the serpentinites described in parts of the Alps are exposed remnants of this ductile shear zone. Associated ophicalcite breccias tell of sea floor exposure, while high

  8. Neurotransmitters couple brain activity to subventricular zone neurogenesis

    Science.gov (United States)

    Young, Stephanie Z.; Taylor, M. Morgan; Bordey, Angélique

    2011-01-01

    Adult neurogenesis occurs in two privileged microenvironments, the hippocampal subgranular zone of the dentate gyrus and the subventricular zone (SVZ) along the lateral ventricle. This review focuses on accumulating evidence suggesting that the activity of specific brain regions or bodily states influences SVZ cell proliferation and neurogenesis. Neuromodulators such as dopamine and serotonin have been shown to have long-range effects through neuronal projections into the SVZ. Local GABA and glutamate signaling have demonstrated effects on SVZ proliferation and neurogenesis, but an extra-niche source of these neurotransmitters remains to be explored and options will be discussed. There is also accumulating evidence that diseases and bodily states such as Alzheimer's disease, seizures, sleep, and pregnancy influence SVZ cell proliferation. With such complex behavior and environmentally-driven factors that control subregion-specific activity, it will become necessary to account for overlapping roles of multiple neurotransmitter systems on neurogenesis when developing cell therapies or drug treatments. PMID:21395856

  9. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    Energy Technology Data Exchange (ETDEWEB)

    J. Conca

    2000-12-20

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

  10. proprietes hydriques des sols dans deux zones a ecosystemes ...

    African Journals Online (AJOL)

    micro climat. Ce changement au niveau du couvert végétal a une influence sur la bio géochimie, l'hydrologie et le climat de la terre. (Hartemink et al., 2008). La dégradation de la majorité des terres dans les pays de la zone tropicale et subtropicale aride et semi-aride s'est fait suite à l'importance de la pression humaine ...

  11. Scaffolding, the zone of proximal development, and novice programmers

    Directory of Open Access Journals (Sweden)

    Nadia Kastro Awbi

    Full Text Available The work reported here is part of a larger research program that aims to explore the learning strategies that novice computer programmers adopt, the ways in which they integrate knowledge, and the processes they employ when applying their knowledge and skills in different contexts. Our findings, based on a narrative analysis of think-aloud retrospective interviews, indicate that scaffolding can influence progression in learning and can extend a student\\'s zone of proximal development (Vygotsky, 1978.

  12. Resolving the ocean's euphotic zone

    Science.gov (United States)

    Marra, John F.; Lance, Veronica P.; Vaillancourt, Robert D.; Hargreaves, Bruce R.

    2014-01-01

    Measurements of net primary production (P) combined with calculated estimates of phytoplankton respiration (Rp) and gross primary production (G) are used to determine the depth of the ocean's euphotic zone, the autotrophic productive layer. The base of the euphotic zone, the compensation depth (where P=0 and G=Rp), is found to be consistently deeper than the traditionally assumed ‘1% light depth'. It is found to occur, however, at a depth that encompasses the depth range of all, or nearly all, autotrophic biomass. The estimated compensation depth also occurs near the depth of 1% of surface blue light (490 nm), supporting the determination of the ocean's productive layer from satellite ocean color sensors.

  13. Zone Denmark - gasell Taanist / Reet Krause

    Index Scriptorium Estoniae

    Krause, Reet, 1967-

    2006-01-01

    Taanis Viborgis asuva firma Zone Company Denmark, kaubamärgi Zone Denmark ja firma disainerite tutvustus. Ettevõte valmistab disainitooteid roostevabast terasest, klaasist, puidust, kummist jm. Disainer Naja Utzon Popov endast, oma loomingust

  14. Zoning, 2004, East Baton Rouge Parish, Louisiana

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a graphical polygon dataset depicting the zoning boundaries of the East Baton Rouge Parish of the State of Louisiana. Zoning can be defined as the range of...

  15. GIS modeling of introduction zones in Sochi

    Directory of Open Access Journals (Sweden)

    Annenkova Irina Vladimirovna

    2014-11-01

    Defined the mean monthly temperature and precipitation for each zone. The diagram shows the dependence of the probability distribution of the three groups resistance from the mean annual temperature and mean annual precipitation. Describes the climatic conditions of the zones.

  16. United States Stateplane Zones - NAD83

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — U.S. State Plane Zones (NAD 1983) represents the State Plane Coordinate System (SPCS) Zones for the 1983 North American Datum within United States.

  17. United States Stateplane Zones - NAD27

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — U.S. State Plane Zones (NAD 1927) represents the State Plane Coordinate System (SPCS) Zones for the 1927 North American Datum within United States.

  18. Effectiveness of work zone intelligent transportation systems.

    Science.gov (United States)

    2013-12-01

    In the last decade, Intelligent Transportation Systems (ITS) have increasingly been deployed in work zones by state departments of transportation. Also known as smart work zone systems they improve traffic operations and safety by providing real-time...

  19. Buffer Zone Requirements for Soil Fumigant Applications

    Science.gov (United States)

    Updated pesticide product labels require fumigant users to establish a buffer zone around treated fields to reduce risks to bystanders. Useful information includes tarp testing guidance and a buffer zone calculator.

  20. Definition and Characterization of the Habitable Zone

    Science.gov (United States)

    Forget, F.; Turbet, M.; Selsis, F.; Leconte, J.

    2017-11-01

    We review the concept of habitable zone (HZ), why it is useful, and how to characterize it. The HZ could be nicknamed the "Hunting Zone" because its primary objective is now to help astronomers plan observations. This has interesting consequences.

  1. TASK 2: QUENCH ZONE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  2. Life zone investigations in Wyoming

    Science.gov (United States)

    Cary, Merritt

    1917-01-01

    Wyoming is among the foremost of our States in its wealth of natural scenery, culminating in the grandeur of Yellowstone National Park, one of the wonders of the world. In addition to this distinction it posseses vast open plains and lofty mountains whence flow the headwaters of mighty river systems emptying far away to the west into the Pacific Ocean, to the southeast into the Gulf of Mexico, and to the southwest into the Gulf of California. The various slope exposures of its mountain ranges, the fertility of its intervening valleys or basins, and the aridity of its desert spaces present a study of geographic and vertical distribution of wild life that is in many particulars unique.The study of geographic and vertical distribution of life with the governing factors and attendant problems is valuable as a matter of scientific research and in the attainment of practical knowledge. The Biological Survey has been making detailed investigations of the transcontinental life belts, or zones, of North America for some years, and this work has been carried on with special reference to their practical value. It has become increasingly evident that life zones furnish a fairly accurate index to average climatic conditions and, therefore, are useful as marking the limits of agricultural possibilities, so far as these are dependent upon climate. The knowledge thus gained has been published and made available as the investigations have progressed and the life zones have been mapped.1

  3. Experiential reflective learning and comfort zone

    Directory of Open Access Journals (Sweden)

    Jan Nehyba

    2011-09-01

    Full Text Available The article deals with the issue of experiential reflective learning. Firstlyit aims to discuss the concept of comfort zone in this area. It goes beyond the usualdefinition of the domestic comfort zone and it reflects in terms of experiential reflectivelearning in the world. The conclusions point to possible parallels with the concept ofcomfort zones and K. Lewin theory. Overall, the article focuses on topics that help toexpand the view on the issue of comfort zone.

  4. Does zoning winter recreationists reduce recreation conflict?

    Science.gov (United States)

    Aubrey D. Miller; Jerry J. Vaske; John R. Squires; Lucretia E. Olson; Elizabeth K. Roberts

    2017-01-01

    Parks and protected area managers use zoning to decrease interpersonal conflict between recreationists. Zoning, or segregation, of recreation - often by nonmotorized and motorized activity - is designed to limit physical interaction while providing recreation opportunities to both groups. This article investigated the effectiveness of zoning to reduce recreation...

  5. Recent findings relating to firefighter safety zones

    Science.gov (United States)

    Bret Butler; Russ Parsons; William Mell

    2015-01-01

    Designation of safety zones is a primary duty of all wildland firefighters. Unfortunately, information regarding what constitutes an adequate safety zone is inadequately defined. Measurements of energy release from wildland fires have been used to develop an empirically based safety zone guideline. The basis for this work is described here.

  6. A new conceptual model for damage zone evolution with fault growth

    Science.gov (United States)

    de Joussineau, G.; Aydin, A.

    2006-12-01

    Faults may either impede or enhance fluid flow in the subsurface, which is relevant to a number of economic issues (hydrocarbon migration and entrapment, formation and distribution of mineral deposits) and environmental problems (movement of contaminants). Fault zones typically comprise a low-permeability core made up of intensely deformed fault rock and a high-permeability damage zone defined by fault-related fractures. The geometry, petrophysical properties and continuity of both the fault core and the damage zone have an important influence on the mechanical properties of the fault systems and on subsurface fluid flow. Information about fault components from remote seismic methods is limited and is available only for large faults (slip larger than 20-100m). It is therefore essential to characterize faults and associated damage zones in field analogues, and to develop conceptual models of how faults and related structures form and evolve. Here we present such an attempt to better understand the evolution of fault damage zones in the Jurassic Aztec Sandstone of the Valley of Fire State Park (SE Nevada). We document the formation and evolution of the damage zone associated with strike-slip faults through detailed field studies of faults of increasing slip magnitudes. The faults initiate as sheared joints with discontinuous pockets of damage zone located at fault tips and fault surface irregularities. With increasing slip (slip >5m), the damage zone becomes longer and wider by progressive fracture infilling, and is organized into two distinct components with different geometrical and statistical characteristics. The first component of the damage zone is the inner damage zone, directly flanking the fault core, with a relatively high fracture frequency and a thickness that scales with the amount of fault slip. Parts of this inner zone are integrated into the fault core by the development of the fault rock, contributing to the core's progressive widening. The second

  7. Microbial oceanography of anoxic oxygen minimum zones.

    Science.gov (United States)

    Ulloa, Osvaldo; Canfield, Donald E; DeLong, Edward F; Letelier, Ricardo M; Stewart, Frank J

    2012-10-02

    Vast expanses of oxygen-deficient and nitrite-rich water define the major oxygen minimum zones (OMZs) of the global ocean. They support diverse microbial communities that influence the nitrogen economy of the oceans, contributing to major losses of fixed nitrogen as dinitrogen (N(2)) and nitrous oxide (N(2)O) gases. Anaerobic microbial processes, including the two pathways of N(2) production, denitrification and anaerobic ammonium oxidation, are oxygen-sensitive, with some occurring only under strictly anoxic conditions. The detection limit of the usual method (Winkler titrations) for measuring dissolved oxygen in seawater, however, is much too high to distinguish low oxygen conditions from true anoxia. However, new analytical technologies are revealing vanishingly low oxygen concentrations in nitrite-rich OMZs, indicating that these OMZs are essentially anoxic marine zones (AMZs). Autonomous monitoring platforms also reveal previously unrecognized episodic intrusions of oxygen into the AMZ core, which could periodically support aerobic metabolisms in a typically anoxic environment. Although nitrogen cycling is considered to dominate the microbial ecology and biogeochemistry of AMZs, recent environmental genomics and geochemical studies show the presence of other relevant processes, particularly those associated with the sulfur and carbon cycles. AMZs correspond to an intermediate state between two "end points" represented by fully oxic systems and fully sulfidic systems. Modern and ancient AMZs and sulfidic basins are chemically and functionally related. Global change is affecting the magnitude of biogeochemical fluxes and ocean chemical inventories, leading to shifts in AMZ chemistry and biology that are likely to continue well into the future.

  8. Dietary attitudes and behaviours of women in China after the 2008 Wenchuan earthquake in three seismically different zones.

    Science.gov (United States)

    Hu, Ping; Han, Ling-Li; Hou, Feng-Gang; Xu, Xiang-Long; Sharma, Manoj; Zhao, Yong

    2016-12-01

    The sudden occurrence of the 2008 Wenchuan Earthquake not only devastated people's health, but also may have impacted on the psychological and dietary attitudes and behaviours of the survivors. Although the influence of natural disaster on people's health has been extensively investigated, there is a lack of information about the effects on people's dietary attitudes and behaviours. Our aim was to evaluate the influence of the Wenchuan earthquake on the dietary attitudes and behaviours of adult women from different zones of China in July 2008. 736 women, aged 18-55 years old, were randomly selected and interviewed after the earthquake. Women were selected from three zones: the earthquake zone (n=206), the shaking zone (n=326), and the non-seismic zone (n=204). Although nutrition knowledge mean scores of women in the three zones were relatively low, the women in the earthquake zone became more vigilant about the nutritional value and acceptability of food than women in the other two zones. Nevertheless, women in the earthquake zone also developed some arguably untoward, if understandable, behaviour after the disaster. They increased their consumption and tendency to stock instant food and snack items. That said, these findings were modulated by other factors such as age, residence, Body Mass Index (BMI), and nutrition knowledge itself, as were post-earthquake eating behaviours, as judged by the ordinal logistic regression analyses performed. The major Wenchuan earthquake was associated with differentials in dietary attitudes and behaviours among women by seismic zone.

  9. 76 FR 18674 - Security Zones; Sector Southeastern New England Captain of the Port Zone

    Science.gov (United States)

    2011-04-05

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zones; Sector Southeastern New England Captain... Southeastern New England Captain of the Port (COTP) Zone. These security zones are nearly identical to security... escorted by Coast Guard or law enforcement agencies assisting the Coast Guard. These zones are needed to...

  10. WorkZoneQ user guide for two-lane freeway work zones.

    Science.gov (United States)

    2013-06-01

    WorkZoneQ was developed in Visual Basic for Applications (VBA) to implement the results of the previous study, : Queue and Users Costs in Highway Work Zones. This report contains the WorkZoneQ user guide. WorkZoneQ : consists of eight Excel ...

  11. 76 FR 7107 - Quarterly Listings; Safety Zones, Security Zones, Special Local Regulations, Drawbridge Operation...

    Science.gov (United States)

    2011-02-09

    ... Zones (Part 165)...... 6/17/2009 USCG-2009-0506 Marietta, OH Safety Zones (Part 165)...... 7/11/2009... Safety Zones (Part 165)...... 9/6/2009 USCG-2009-0695 Ohio River, PA Safety Zones (Part 165)...... 8/9...

  12. 33 CFR 165.503 - Security Zone; Captain of the Port Hampton Roads Zone.

    Science.gov (United States)

    2010-07-01

    ... § 165.503 Security Zone; Captain of the Port Hampton Roads Zone. (a) Definitions. As used in this... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Captain of the Port Hampton Roads Zone. 165.503 Section 165.503 Navigation and Navigable Waters COAST GUARD...

  13. The potential of agroforestry to increase primary production in the Sahelian and Sundanian zone of West Africa.

    NARCIS (Netherlands)

    Kessler, J.J.; Breman, H.

    1991-01-01

    Primary production is limited by water availability in the N Sahelian zone only; elsewhere in the region nutrient availablility is critical. Woody species influence the water balance via rainfall interception, the influence on evapotranspiration and the influence on water infiltration. The ultimate

  14. Human dissemination of genes and microorganisms in Earth's Critical Zone.

    Science.gov (United States)

    Zhu, Yong-Guan; Gillings, Michael; Simonet, Pascal; Stekel, Dov; Banwart, Steven; Penuelas, Josep

    2017-12-20

    Earth's Critical Zone sustains terrestrial life and consists of the thin planetary surface layer between unaltered rock and the atmospheric boundary. Within this zone, flows of energy and materials are mediated by physical processes and by the actions of diverse organisms. Human activities significantly influence these physical and biological processes, affecting the atmosphere, shallow lithosphere, hydrosphere, and biosphere. The role of organisms includes an additional class of biogeochemical cycling, this being the flow and transformation of genetic information. This is particularly the case for the microorganisms that govern carbon and nitrogen cycling. These biological processes are mediated by the expression of functional genes and their translation into enzymes that catalyze geochemical reactions. Understanding human effects on microbial activity, fitness and distribution is an important component of Critical Zone science, but is highly challenging to investigate across the enormous physical scales of impact ranging from individual organisms to the planet. One arena where this might be tractable is by studying the dynamics and dissemination of genes for antibiotic resistance and the organisms that carry such genes. Here we explore the transport and transformation of microbial genes and cells through Earth's Critical Zone. We do so by examining the origins and rise of antibiotic resistance genes, their subsequent dissemination, and the ongoing colonization of diverse ecosystems by resistant organisms. © 2017 John Wiley & Sons Ltd.

  15. Holdridge life zone physical inconsistency

    Science.gov (United States)

    Martínez, A., Sr.; Ochoa, A.

    2015-12-01

    Life zones is a very used classification system, developed by L.R. Holdridge in 1967, used to discern why plants have different adaptation mechanism to their surrounding environment. In this paper, the relation between potential evapotranspiration rate (ETr ), anual precipitation (P ) and biotemperature (Tb ) in the Holdridge triangle, is parametrized (P = (500/9)*ETr) to evaluate if the rain process is conserved in Colombia. Further, an adiabatic ascent of air with diurnal and interannual variability, and cluster analysis is view as a classification example of the advantage of using physical process to evaluate the plants adaptation mechanisms . The most inconsistency life zones are situated in the rainiest places of Colombian pacific costs in tropical latitudinal region, are non-exist places in holdridge triangle with annual biotemperature higher than 26◦ C, annual precipitation about 10.000mm and annual potential evapotranspiration rate about 0.1. The difference between Holdridge predicted precipitation and the precipitation measured with TRMM are about 5.000mm in these places. Classification systems based on an annual average, do not stablish adaptation as a function of diurnal variability, for example, the difference between valley sides vegetation could not being determined. This kind of limitations, added to a validation procces and the auscence of a physic procces in the variable interaction, make the Holdridge Life Zones a very useful tool, but physically inconsistent for caracterice vegetation as a function of precipitation. The rain process is very complex, depend of mass and energy exchanges and is still a controversial topic in atmospheric modeling, as a biotic pump.

  16. Land governance as grey zone

    DEFF Research Database (Denmark)

    Kjær, Anne Mette

    2017-01-01

    Weak state capacity has often been in focus when explaining why land reform in sub-Saharan Africa is not implemented. However, an analysis of the deeper politics of land reform brings our attention to a set of incentives which allow rules governing land to be open to interpretation. This article...... demonstrates that in Uganda, the need to maintain the ruling coalition in a clientelist political settlement to build electoral support, and the desire to attract economic investors, constitute political incentives to maintain land governance as a grey zone, even if there is apparent political...... will to implement land reforms....

  17. A flow system with zone merging and zone trapping in the main reactor applied to spectrophotometric catalytic determination of cobalt in grasses.

    Science.gov (United States)

    Gomes, Taciana F; Vida, Ana C F; Sasaki, Milton K; Silva, Claudineia R; Barros, Valdemir A F; Zagatto, Elias A G

    2012-12-15

    A flow system with zone merging and zone trapping in the main reactor was proposed. The sample and reagent inserted aliquots merge together and the resulting zone is directed towards a displaceable reactor inside which its most concentrated portion is trapped. After the pre-set TRAP period, the handled sample is released towards detection. A comparison with an analogous flow system exploiting zone stopping revealed the superior characteristics of sampling rate and system operation; moreover, the sample inserted volume plays little influence on sampling rate. The system was applied to the spectrophotometric determination of cobalt in pastures, and enhanced figures of merit (sampling rate=18 h(-1); peak height r.s.d.=0.7%, detection limit=0.046 μg L(-1) Co; reagent consumption=330 μg of Tiron per measurement; 98%

  18. Computer simulation of heat transfer in zone plate optics exposed to x-ray FEL radiation

    Science.gov (United States)

    Nilsson, D.; Holmberg, A.; Sinn, H.; Vogt, U.

    2011-06-01

    Zone plates are circular diffraction gratings that can provide diffraction-limited nano-focusing of x-ray radiation. When designing zone plates for X-ray Free Electron Laser (XFEL) sources special attention has to be made concerning the high intensity of the sources. Absorption of x-rays in the zone material can lead to significant temperature increases in a single pulse and potentially destroy the zone plate. The zone plate might also be damaged as a result of temperature build up and/or temperature fluctuations on longer time scales. In this work we simulate the heat transfer in a zone plate on a substrate as it is exposed to XFEL radiation. This is done in a Finite Element Method model where each new x-ray pulse is treated as an instantaneous heat source and the temperature evolution between pulses is calculated by solving the heat equation. We use this model to simulate different zone plate and substrate designs and source parameters. Results for both the 8 keV source at LCLS and the 12.4 keV source at the European XFEL are presented. We simulate zone plates made of high Z metals such as gold, tungsten and iridium as well as zone plates made of low Z materials such as diamond. In the case of metal zone plates we investigate the influence of substrate material by comparing silicon and diamond substrates. We also study the effect of different cooling temperatures and cooling schemes. The results give valuable indications on the temperature behavior to expect and can serve as a basis for future experimental investigations of zone plates exposed to XFEL radiation.

  19. Euphotic Zone Study moves forward

    Science.gov (United States)

    Denman, Kenneth

    The Global Ocean Euphotic Zone Study (GOEZS), a potential core program of the International Geosphere-Biosphere Programme (IGBP) being planned jointly with the Scientific Committee on Oceanic Research (SCOR), was recently given the go-ahead by IGBP's Scientific Committee to move on to the next level of developing its scientific program.The GOEZS program will focus on the coupled physical, biological, and chemical processes operating in the euphotic zone, which is the ocean surface layer where sufficient light penetrates for photosynthesis by phytoplankton to exceed their metabolic energy losses. The upper ocean is extremely important to understanding the atmosphereocean system because it mediates exchanges of heat, momentum, carbon dioxide, sulphur, and nitrogen between the atmosphere and the ocean interior. For the major greenhouse gas carbon dioxide for example, there is more carbon in the upper ocean than in the whole atmosphere. Essentially all carbon dioxide from the atmosphere that passes from the upper ocean to the ocean interior has been transformed chemically or biologically in the upper ocean. Moreover, the upper ocean is the site of all marine shipping and most recreation and industrial activity and contains the planktonic food chain and most fish stocks.

  20. Near-field/altered-zone models report

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, E. L., LLNL

    1998-03-01

    The U.S. Department of Energy is studying Yucca Mountain as the possible site for the first underground repository for permanent disposal of spent fuel from commercial nuclear reactors as well as for other types high-level nuclear waste. Emplacement of high-level radioactive waste, especially commercial spent nuclear fuel (CSNF), in Yucca Mountain will release a large amount of heat into the rock above and below the repository. The heating rate will decrease with time, creating a thermal pulse. Over a period of several thousand years, the rock temperature will rise initially, then drop when the production of decay heat falls below the rate at which heat escapes from the hot zone. Besides raising the rock temperature, much of this heat will vaporize water, which will then condense in cooler regions. The condensate is likely to form a gravity-driven heat pipe above the repository, creating the possibility that water may drain back onto the waste packages (WPs) or that it may ''shed'' through the pillars between emplacement drifts. The long-term importance of these effects has been investigated through the development, testing, and application of thermohydrologic (TH) models. Other effects, such coupled chemical and mechanical processes, may also influence the movement of water above, within, and below the emplacement drifts. A recent report on thermally driven coupled processes (Hardin and Chesnut, 1997) provides a qualitative assessment of the probable significance of these processes for the Yucca Mountain Site Characterization Project (YMSCP) and is the phenomenological framework for the present report. This report describes the conceptual and numerical models that have been developed to predict the thermal, mechanical, hydrologic, and chemical responses to the cumulative heat production of the potential host rock at Yucca Mountain. As proposed, the repository horizon will be situated within the Topopah Spring tuff, in the adjacent middle

  1. Analysis of bed joint influence on masonry modulus of elasticity

    OpenAIRE

    Zavalis, R.; Jonaitis, B.; Paulo B. Lourenço

    2014-01-01

    The means of determining the modulus of elasticity presented in technical literature often underestimate factors such as the influence of mechanical properties of the bed joint mortar and the influence of contact zone of the masonry unit and mortar on the elasticity modulus. Research carried out by the authors show that the modulus of elasticity of the bed joint considering influence of the contact zone (effective modulus of elasticity) is 3 to 25 times less than mortar modulus of...

  2. Of floating-zone uranium; Sur l'uranium de zone flottante

    Energy Technology Data Exchange (ETDEWEB)

    Clottes, G. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-01-01

    The floating zone method has been chosen in order to purify uranium. The various parameters occurring in this purification technique, have been studied theoretically and technologically. The speed that proves to be the most efficient is 0,7 cm/h, the direction can only upwards, and the fusion must take place under pressure of 10{sup -7} Torr or so. Besides such problems concerning purification, the study of the floating zone stability led us to define a field touching the size and diameter of uranium drops, which, on the one hand coincides with Heywang's conditions and, on the other hand, is compatible with a fusion in the core of the bar. Such field shows that the floating zone can easily apply to bars whose diameter is included between 5 and 10 mm, and that it cannot work out when the diameter exceeds 21 mm. The apparatus, consisting in a means of heating by electronic bombardment under ultra-vacuum is conditioned by the various parameters that have been studied. As the analysis results were insufficient, the uranium thus dealt with has been characterized by metallurgic and physical tests: micrographic tests, measures of microhardness, measures of electric resistivity at a low temperature, have shown a definite purification at the bar-head; these results have been confirmed by the lowering at 270 C of the temperature of recrystallization together with the definite tendency of the refined metal to polygonize. The measures of electric resistivity constitute an easy and quantitative way of figuring out the metal purity. The influence of an impurity on the electric resistivity of uranium has been studied by U-Au alloys with a weak concentration of gold. The two important following points are brought out be these experiences: 1 - the measure of electric resistivity should be worked out on anneal bars in {gamma} phase and cooled. 2 - Gold has a very strong influence on uranium; the value 500 {mu}{omega}cm per cent of gold enabled us to give a total concentration

  3. Syntactic Idioms and Precedent Phenomena: Intersection Zones

    Directory of Open Access Journals (Sweden)

    Hanna Sytar

    2016-08-01

    Full Text Available Background: One examined mainly structural and semantic features of syntactic idioms so far. The pragmatic dimension of these original units that are on the verge of syntax and phraseology, has not been highlighted properly in the scientific literature, so it needs theoretical understanding. The combination of syntactic idiom and phraseological phenomenon refers to the communication techniques impacting on message recipient. Purpose: to analyze the intersection zones of syntactic idioms and precedent phenomena. Results: Analysis of the collected factual material allows to distinguish two areas of interpenetration of syntactic idioms and precedent units: 1 construction of expression according to the phraseologized model, within which the position of variable component is filled by the precedent name or precedent expression; 2 the model of sentence itself is precedent, and lexical content does not comply with generally known one that does not affect on understanding of model content by recipient. With a combination of syntactic idiom and precedent phenomena speakers provide drawing of recipients’ attention, carry out a hidden influence on them, express their own attitude to the realities, so that perform phatic, manipulative and expressive-evaluative functions. The modifications and transformations of precedent expressions and names appeared to be regular in such interpenetrations. Discussion: The obtained results reflect the general trend towards transform (transformation, modification, variation, etc. of precedent, as well as phraseological units, and can be used for the analysis of patterns of their formation and modifications. Further research phase implies tracing patterns of syntactic idioms combination with other means of expressive syntax.

  4. Viewing Race in the Comfort Zone

    Directory of Open Access Journals (Sweden)

    Brenda L. Hughes

    2014-08-01

    Full Text Available Carter suggests the concept of a “comfort zone” to explain the inability of dramatic African American programs to be successful on television. He argues that a workable formula has been developed for successful African American series, “portray black people in a way that would be acceptable to the millions of potential purchasers (whites of advertised products. That is, non-threatening and willing to ‘stay in their place.’”. Using a data set constructed from television ratings and shares, this study examines “black-centeredness” within the context of program success and failure. The comfort zone concept argues Black-centered television series are only successful in a comedic genre because White audiences, who have the majority of the ratings power, will only watch Black-centered series with which they are comfortable. The findings suggest that, in general, race, that is Black-centeredness, did not negatively influence program ratings or shares.

  5. Ants exhibit asymmetric hybridization in a mosaic hybrid zone.

    Science.gov (United States)

    Purcell, Jessica; Zahnd, Sacha; Athanasiades, Anouk; Türler, Rebecca; Chapuisat, Michel; Brelsford, Alan

    2016-10-01

    Research on hybridization between species provides unparalleled insights into the pre- and postzygotic isolating mechanisms that drive speciation. In social organisms, colony-level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping-by-sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single-queen and multiple-queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects. © 2016 John Wiley & Sons Ltd.

  6. Numerical models of slab migration in continental collision zones

    Directory of Open Access Journals (Sweden)

    V. Magni

    2012-09-01

    Full Text Available Continental collision is an intrinsic feature of plate tectonics. The closure of an oceanic basin leads to the onset of subduction of buoyant continental material, which slows down and eventually stops the subduction process. In natural cases, evidence of advancing margins has been recognized in continental collision zones such as India-Eurasia and Arabia-Eurasia. We perform a parametric study of the geometrical and rheological influence on subduction dynamics during the subduction of continental lithosphere. In our 2-D numerical models of a free subduction system with temperature and stress-dependent rheology, the trench and the overriding plate move self-consistently as a function of the dynamics of the system (i.e. no external forces are imposed. This setup enables to study how continental subduction influences the trench migration. We found that in all models the slab starts to advance once the continent enters the subduction zone and continues to migrate until few million years after the ultimate slab detachment. Our results support the idea that the advancing mode is favoured and, in part, provided by the intrinsic force balance of continental collision. We suggest that the advance is first induced by the locking of the subduction zone and the subsequent steepening of the slab, and next by the sinking of the deepest oceanic part of the slab, during stretching and break-off of the slab. These processes are responsible for the migration of the subduction zone by triggering small-scale convection cells in the mantle that, in turn, drag the plates. The amount of advance ranges from 40 to 220 km and depends on the dip angle of the slab before the onset of collision.

  7. Groundwater suitability recharge zones modelling - A GIS application

    Science.gov (United States)

    Dabral, S.; Bhatt, B.; Joshi, J. P.; Sharma, N.

    2014-11-01

    Groundwater quality in Gujarat state is highly variable and due to multiplicity of factors viz. influenced by direct sea water encroachment, inherent sediment salinity, water logging, overexploitation leading to overall deterioration in ground water quality, coupled with domestic and industrial pollution etc. The groundwater scenario in the state is not very encouraging due to imbalance between recharge and groundwater exploitation. Further, the demand for water has increased manifold owing to agricultural, industrial and domestic requirement and this has led to water scarcity in many parts of the state, which is likely to become more severe in coming future due to both natural and manmade factors. Therefore, sustainable development of groundwater resource requires precise quantitative assessment based on reasonably valid scientific principles. Hence, delineation of groundwater potential zones (GWPZ), has acquired great significance. The present study focuses on the integrated Geospatial and Multi-Criteria Decision Making (MCDM) techniques to determine the most important contributing factors that affect the groundwater resources and also to delineate the potential zones for groundwater recharge. The multiple thematic layers of influencing parameters viz. geology, geomorphology, soil, slope, drainage density and land use, weightages were assigned to the each factor according to their relative importance as per subject experts opinion owing to the natural setup of the region. The Analytical Hierarchy Process (AHP) was applied to these factors and potential recharge zones were identified. The study area for the assessment of groundwater recharge potential zones is Mahi-Narmada inter-stream region of Gujarat state. The study shows that around 28 % region has the excellent suitability of the ground water recharge.

  8. Review of unsaturated-zone transport and attenuation of volatile organic compound (VOC) plumes leached from shallow source zones.

    Science.gov (United States)

    Rivett, Michael O; Wealthall, Gary P; Dearden, Rachel A; McAlary, Todd A

    2011-04-25

    good opportunity for further sensitivity analysis and development to practitioner use. There remains a significant need to obtain intermediate laboratory-scale and particularly field-scale (actual site and controlled release) datasets that address the scenario as a whole and permit validation of the available models. Integrated assessment of the range of simultaneous processes that combine to influence leached plume generation, transport and attenuation in the unsaturated zone is required. Component process research needs are required across the problem scenario and include: the simultaneous volatilisation and dissolution of source zones; development of appropriate field-scale dispersion estimates for the unsaturated zone; assessment of transient VOC exchanges between aqueous, vapour and sorbed phases and their influence upon plume attenuation; development of improved field methods to recognise and quantify biodegradation of CAHs; establishment of the influence of co-contaminants; and, finally, translation of research findings into more robust practitioner practice. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Yellow light dilemma zone researches: a review

    Directory of Open Access Journals (Sweden)

    Yaping Zhang

    2014-10-01

    Full Text Available The yellow light dilemma zone is widely known as an area on the high-speed intersection approach, where vehicles neither safely stop before the stop line nor proceed through the intersection during amber interval. Within such an area, a vehicle might be involved in a right-angle crash or rear-end collision. This issue has been extensively discussed over five decades in traffic engineering field, covering from theory to practice. However, few comprehensive review literatures on the amber signal dilemma zone problems can be found. The objective of this paper is to summarize the evolution of yellow light dilemma zone researches. Basic definition and boundary of dilemma zone followed by driver behavior and dilemma zone hazard measurement are depicted. At last, the future directions of yellow light dilemma zone research are discussed.

  10. Impact of the overriding plate rheology on convergence zone dynamics.

    Science.gov (United States)

    Hertgen, Solenn; Yamato, Philippe; Guillaume, Benjamin; van Hunen, Jeroen

    2017-04-01

    Most of deformation at the Earth's surface is localized at plate boundaries. This deformation can be accommodated in very different ways depending on the tectonic setting. In the case of convergence zones, the deformation is typically simplified and classified as follows: - intra-oceanic convergence, when convergence involves two oceanic lithospheres, which generally leads to the subduction/obduction initiation and to the formation of an island arc; - convergence between an oceanic and a continental lithosphere, which is mainly accommodated by subduction and can lead to the formation of a mountain range at the plate boundary; - convergence involving two continental lithospheres, which is accommodated by collision and leads to the formation of a mountain range produced by the stacking of crustal slices. Different materials are thus involved (i.e., oceanic crust, continental crust, sediments). Depending on the context (oceanic or continental subduction), they can form contrasted structures in terms of units size, morphology and metamorphism (e.g., Alps vs. Andes/Altiplano-Puna). Moreover, some convergent zones with apparently similar tectonic settings (e.g., continent/continent convergence) show very different patterns of deformation with either very localized deformation (e.g., the Alps) or, at the opposite, deformation distributed over thousands of kilometers (e.g, Himalayas/Tibet). Finally, other convergent zones from different tectonic settings seem to show similar structures (e.g., Tibet plateau and Altiplano-Puna plateaus). Although the mechanism of plate convergence appears to be the same in each case, the structures obtained at the surface seem to be unique. Rheology of both the subducting plate and of the plate interface is known to influence the convergence zones dynamics. However, very few studies have addressed the role of the overriding plate rheology in details, while it may also exert a large control on the deformation style at plate boundaries. In

  11. Marginal Ice Zone: Biogeochemical Sampling with Gliders

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Marginal Ice Zone: Biogeochemical Sampling with Gliders...under the ice and in the marginal ice zone. The project specific goals are to develop biogeochemical and optical proxies for glider optics; to use the...water, in the marginal ice zone, and under the ice; to use glider optical measurements to compute fields of rates of photosynthetic carbon fixation

  12. Demarcation of secondary hyperalgesia zones

    DEFF Research Database (Denmark)

    Ringsted, Thomas K; Enghuus, Casper; Petersen, Morten A

    2015-01-01

    BACKGROUND: Secondary hyperalgesia is increased sensitivity in normal tissue near an injury, and it is a measure of central sensitization reflecting injury-related effects on the CNS. Secondary hyperalgesia areas (SHAs), usually assessed by polyamide monofilaments, are important outcomes in studies...... of analgesic drug effects in humans. However, since the methods applied in demarcating the secondary hyperalgesia zone seem inconsistent across studies, we examined the effect of a standardized approach upon the measurement of SHA following a first degree burn injury (BI). NEW METHOD: The study was a two......-observer, test-retest study with the two sessions separated by 6wk. An observer-blinded design adjusted to examine day-to-day and observer-to-observer variability in SHA was used. In 23 healthy volunteers (12 females/11 males) a BI was induced by a contact thermode (47.0°C, 420s, 2.5×5.0cm(2)). The SHA...

  13. The Coastal Transition Zone Program

    Science.gov (United States)

    The Coastal Transition Zone Group

    The Coastal Transition Zone (CTZ) Program, sponsored by the Office of Naval Research (Coastal Sciences and Oceanic Biology programs), is designed to investigate the cold tongues ("filaments") often observed in satellite sea surface temperature images of the waters off the west coast of North America. The cold filaments are not unique to this region, since similar features have also been observed along other coasts around the world, including those near Portugal and southwestern Africa. The discovery of these features is an excellent example of the power of satellite observations, because although the filaments are quite prominent in the satellite images, years of regular shipboard observations did not reveal them. On the other hand, the study of cold tongues also illustrates the necessity of on-site observations, because the nature, structure, causes, and effects of filaments cannot be determined from the satellite observations alone.

  14. Vegetation zones in changing climate

    Science.gov (United States)

    Belda, Michal; Holtanova, Eva; Halenka, Tomas; Kalvova, Jaroslava

    2017-04-01

    Climate patterns analysis can be performed for individual climate variables separately or the data can be aggregated using e.g. some kind of climate classification. These classifications usually correspond to vegetation distribution in the sense that each climate type is dominated by one vegetation zone or eco-region. Thus, the Köppen-Trewartha classification provides integrated assessment of temperature and precipitation together with their annual cycle as well. This way climate classifications also can be used as a convenient tool for the assessment and validation of climate models and for the analysis of simulated future climate changes. The Köppen-Trewartha classification is applied on full CMIP5 family of more than 40 GCM simulations and CRU dataset for comparison. This evaluation provides insight on the GCM performance and errors for simulations of the 20th century climate. Common regions are identified, such as Australia or Amazonia, where many state-of-the-art models perform inadequately. Moreover, the analysis of the CMIP5 ensemble for future under RCP 4.5 and RCP 8.5 is performed to assess the climate change for future. There are significant changes for some types in most models e.g. increase of savanna and decrease of tundra for the future climate. For some types significant shifts in latitude can be seen when studying their geographical location in selected continental areas, e.g. toward higher latitudes for boreal climate. Quite significant uncertainty can be seen for some types. For Europe, EuroCORDEX results for both 0.11 and 0.44 degree resolution are validated using Köppen-Trewartha types in comparison to E-OBS based classification. ERA-Interim driven simulations are compared to both present conditions of CMIP5 models as well as their downscaling by EuroCORDEX RCMs. Finally, the climate change signal assessment is provided using the individual climate types. In addition to the changes assessed similarly as for GCMs analysis in terms of the area

  15. NOAA Average Annual Salinity (3-Zone)

    Data.gov (United States)

    California Department of Resources — The 3-Zone Average Annual Salinity Digital Geography is a digital spatial framework developed using geographic information system (GIS) technology. These salinity...

  16. 76 FR 38297 - Safety Zone; Marine Events Requiring Safety Zones in the Captain of the Port Sault Sainte Marie Zone

    Science.gov (United States)

    2011-06-30

    ... areas within the Sector Sault Sainte Marie Captain of the Port zone. These safety zones are necessary to protect spectators, participants, and vessels from the hazards associated with various maritime events... would inhibit the Coast Guard's ability to protect the public from the hazards associated with various...

  17. Mercury and methylmercury dynamics in the hyporheic zone of an Oregon stream

    Science.gov (United States)

    Hinkle, Stephen R.; Bencala, Kenneth E.; Wentz, Dennis A.; Krabbenhoft, David P.

    2014-01-01

    The role of the hyporheic zone in mercury (Hg) cycling has received limited attention despite the biogeochemically active nature of this zone and, thus, its potential to influence Hg behavior in streams. An assessment of Hg geochemistry in the hyporheic zone of a coarse-grained island in the Coast Fork Willamette River in Oregon, USA, illustrates the spatially dynamic nature of this region of the stream channel for Hg mobilization and attenuation. Hyporheic flow through the island was evident from the water-table geometry and supported by hyporheic-zone chemistry distinct from that of the bounding groundwater system. Redox-indicator species changed abruptly along a transect through the hyporheic zone, indicating a biogeochemically reactive stream/hyporheic-zone continuum. Dissolved organic carbon (DOC), total Hg, and methylmercury (MeHg) concentrations increased in the upgradient portion of the hyporheic zone and decreased in the downgradient region. Total Hg (collected in 2002 and 2003) and MeHg (collected in 2003) were correlated with DOC in hyporheic-zone samples: r2=0.63 (total Hg-DOC, 2002), 0.73 (total Hg-DOC, 2003), and 0.94 (MeHg-DOC, 2003). Weaker Hg/DOC association in late summer 2002 than in early summer 2003 may reflect seasonal differences in DOC reactivity. Observed correlations between DOC and both total Hg and MeHg reflect the importance of DOC for Hg mobilization, transport, and fate in this hyporheic zone. Correlations with DOC provide a framework for conceptualizing and quantifying Hg and MeHg dynamics in this region of the stream channel, and provide a refined conceptual model of the role hyporheic zones may play in aquatic ecosystems.

  18. Policy Change Implication Toward Integrated Wonorejo Zone as A Strategic Economic Development Zone

    Directory of Open Access Journals (Sweden)

    Akbar Pandu Dwinugraha

    2014-04-01

    Full Text Available Integrated Wonorejo Zone is one of the development zone in Lumajang Regency with significant goals to improve potensial condition in three aspect namely tourism, agriculture and SMEs. Based on RTRW in 2008-2028, which was established in 2008, the development strategy of this zone is change. Integrated Wonorejo Zone was mentioned as a Strategic Economic Development Zone. This research describe and analyse about how the implication of policy change toward Integrated Wonorejo Zone. This research using method of descriptive research with qualitative approach as well as analysis of data by John Seidel about QDA (qualitative data analysis. The result of this research explain that the policy change implication, from description, implementation and implication point of view did not give significant expectation. Key Words: Policy Change, Integrated Wonorejo Zone, Strategic Economic Development Zone.

  19. Sound Zones: On Performance Prediction of Contrast Control Methods

    DEFF Research Database (Denmark)

    Møller, Martin Bo; Olsen, Martin

    2016-01-01

    Low frequency personal sound zones can be created by controlling the squared sound pressure in separate spatial confined control regions. Several methods have been proposed for realizing this scenario, with different constraints and performance. Extrapolating knowledge of the resulting acoustic...... separation from predicted results is a challenge as the obtainable performance relies on both physical setup and the chosen evaluation procedure. In this paper, the influence of the evaluation method is highlighted. Using the proposed evaluation four different control strategies for generation of low...

  20. 76 FR 41073 - Security Zones; Sector Southeastern New England Captain of the Port Zone

    Science.gov (United States)

    2011-07-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zones; Sector Southeastern New England Captain... establishing security zones around cruise ships in the Southeastern New England Captain of the Port (COTP) Zone... around any cruise ship underway that is being escorted by Coast Guard or law enforcement agencies...

  1. 77 FR 25375 - Emergency Planning Zone

    Science.gov (United States)

    2012-04-30

    ... COMMISSION 10 CFR Parts 50 and 52 Emergency Planning Zone AGENCY: Nuclear Regulatory Commission. ACTION... requests that the NRC amend its regulations to expand the Emergency Planning Zones (EPZs) for nuclear power... power plants and who are concerned that current NRC emergency planning requirements are not adequate to...

  2. Generalized provisional seed zones for native plants

    Science.gov (United States)

    Andrew D. Bower; J. Bradley St.Clair; Vicky. Erickson

    2014-01-01

    Deploying well-adapted and ecologically appropriate plant materials is a core component of successful restoration projects. We have developed generalized provisional seed zones that can be applied to any plant species in the United States to help guide seed movement. These seed zones are based on the intersection of high-resolution climatic data for winter minimum...

  3. unguiculata (L.) Walp) from Three Agroecological Zones

    African Journals Online (AJOL)

    zyme gene loci there was about 9% allelic substitution among the accessions. Aver- age genetic distance values of 0.068,0.048 and 0.128 within Deciduous forest, Guinea savanna and Sudan Savanna zones, respec- tively, also implied that within these agroecological zones there were about 7 %,. 5% and 13% allelic ...

  4. Perception coherence zones in flight simulation

    NARCIS (Netherlands)

    Valente Pais, A.R.; Paassen, M.M. van; Mulder, M.; Wentink, M.

    2010-01-01

    The development and tuning of flight simulator motion filters relies on understanding human motion perception and its limitations. Of particular interest to flight simulation is the study of visual-inertial coherence zones. Coherence zones refer to combinations of visual and inertial cues that,

  5. Zone refining of cadmium and related characterization

    Indian Academy of Sciences (India)

    Unknown

    Abstract. We present the zone refining results of cadmium using horizontal resistive zone refiner under constant flow of moisture free hydrogen gas. The boron impurity in cadmium can be avoided using quartz (GE 214 grade) boat in lieu of high pure graphite boat. The analytical results using inductively coupled plasma ...

  6. Efforts to update firefighter safety zone guidelines

    Science.gov (United States)

    Bret Butler

    2009-01-01

    One of the most critical decisions made on wildland fires is the identification of suitable safety zones for firefighters during daily fire management operations. To be effective (timely, repeatable, and accurate), these decisions rely on good training and judgment, but also on clear, concise guidelines. This article is a summary of safety zone guidelines and the...

  7. Work zone performance measures pilot test.

    Science.gov (United States)

    2011-04-01

    Currently, a well-defined and validated set of metrics to use in monitoring work zone performance do not : exist. This pilot test was conducted to assist state DOTs in identifying what work zone performance : measures can and should be targeted, what...

  8. Remote sensing applications for coastal zone management

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, L.V.G.

    stream_size 4 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_5.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_5.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  9. Riparian buffer zones as pesticide filters of no-till crops.

    Science.gov (United States)

    Aguiar, Terencio R; Bortolozo, F R; Hansel, F A; Rasera, K; Ferreira, M T

    2015-07-01

    Several studies have pointed to the potential benefits of riparian vegetation as buffer zones for agricultural and industrial pollutants harmful to aquatic ecosystems. However, other studies have called into question its use as an ecological filter, questioning the widths and conditions for which they are effective as a filter. In this work, we have investigated the buffering capacity of the riparian one to retain pesticides in the water-saturated zone, on 27 sites composed by riparian buffer zones with different vegetation structure (woody, shrubs, or grass vegetation) and width (12, 36, and 60 m). Five pesticides were analyzed. The effectiveness of the filtering was largely influenced by the width and vegetation type of the buffer zone. In general, decreasing pesticide removal followed in this order wood > shrubs > grass. The 60 m woody buffer zone was the most effective in the removal of all the pesticides. Only atrazine was detected in this case (0.3 μg L(-1)). Furthermore, a linear correlation (R (2) > 0.97) was observed in their removal for all compounds and buffer zones studied. Thus, preserving the woody vegetation in the riparian zone is important for watershed management and groundwater quality in the no-tillage system in temperate climate.

  10. Parapapillary Deep-Layer Microvasculature Dropout in Primary Open-Angle Glaucoma Eyes With a Parapapillary γ-Zone.

    Science.gov (United States)

    Lee, Eun Ji; Kim, Tae-Woo; Kim, Ji-Ah; Kim, Jeong-Ah

    2017-11-01

    To explore the clinical characteristics of parapapillary deep-layer microvasculature dropout (MvD) associated with parapapillary γ-zone in primary open-angle glaucoma (POAG). A total of 150 eyes with POAG and 75 age- and axial length-matched control eyes, both having parapapillary γ-zone as determined by spectral-domain (SD) optical coherence tomography (OCT), were included. Parapapillary MvD was defined as a focal sectoral capillary dropout without any visible microvascular network identified in deep-layer en-face images obtained using swept-source OCT angiography (OCTA). Optic nerve heads were imaged using SD-OCT to examine the microstructure of β-parapapillary atrophy, and to measure areas of the β-zones (area with intact Bruch's membrane) and γ-zones (area devoid of Bruch's membrane). Factors associated with the presence of MvD were determined using logistic regression analyses. Parapapillary deep-layer MvD was identified in 117 of 150 POAG eyes (78.0%) with a parapapillary γ-zone, whereas none of the healthy control eyes showed MvD. MvD was universally identified within the γ-zone and additionally involved the β-zone in eyes with both γ- and β-zones. Multivariate logistic regression analyses showed significant influence of thinner global retinal nerve fiber layer (P = 0.001), worse visual field mean deviation (P < 0.001), as well as larger areas of parapapillary γ-zones (P ≤ 0.010) and β-zones (P ≤ 0.005) on the presence of MvD. MvD was frequently identified in the γ-zone in POAG eyes, but not in healthy eyes. Worse visual field loss and larger areas of γ- and β-zones were associated with the presence of MvD in POAG eyes with a parapapillary γ-zone.

  11. Louisiana Speaks Regional Plan Vision Special Economic Zones, UTM Zone 15N NAD83, Louisiana Recovery Authority (2007), [louisiana_speaks_vision_special_economic_zones

    Data.gov (United States)

    Louisiana Geographic Information Center — This GIS shapefile data illustrates special economic zones included in the Louisiana Speaks Regional Plan Vision. Special economic zones include existing national,...

  12. Ranking zones model – a multicriterial approach to the spatial management of urban areas

    Directory of Open Access Journals (Sweden)

    Ivan Marović

    2015-03-01

    Full Text Available Urban investment planning is highly complex and different views are provided by stakeholders and experts as to the scope, scale and potential solutions. The evaluation of such investments requires explicit consideration of multiple, conflicting and incommensurate criteria that have an important social, economic, and environmental influence on various stakeholders in different ways. To take into account all the dimensions, the proposed model is the Ranking Zones Model (RZM, based on PROMETHEE methods. The RZM comprises several steps providing a rank-list of all observed zones. It helps decision-makers come up with consistent decisions as to which zones to invest in and, at the same time, provides reassurance that the decision was based on a proper comparison of all relevant urban zone areas. The advantage of this approach is that even with a change in the decision-making structure, the actual procedure remains consistent.

  13. Steam zone classification in the recovery of bitumen by SAGD technology

    Energy Technology Data Exchange (ETDEWEB)

    Thimm, H.F. [Thimm Petroleum Technologies Inc. (Canada)

    2011-07-01

    In an oil field, steam assisted gravity drainage (SAGD) is used as a thermal recovery process. The presence of gas in the steam zone can affect the ease with which the process can be simulated. The behaviour of gases in the steam zone is strongly influenced by the solubility of these gases in water. The aim of the paper is to look at the behaviour of the gases present in SAGD operations in terms of high temperature solution thermodynamics. The theoretical model was first demonstrated and then results were compared with the field results from several operations in the Athabasca and Cold Lake areas. Field calculations confirmed both the results from the theoretical model and the existence of three distinct types of steam zones in the SAGD process. This paper examined the behaviour of gases in SAGD processes and highlighted the fact that the presence of three types of steam zones has to be taken into consideration in simulations and in field operations.

  14. Research of the electrical anisotropic characteristics of water-conducting fractured zones in coal seams

    Science.gov (United States)

    Su, Ben-Yu; Yue, Jian-Hua

    2017-06-01

    Water flooding disasters are one of the five natural coal-mining disasters that threaten the lives of coal miners. The main causes of this flooding are water-conducting fractured zones within coal seams. However, when resistivity methods are used to detect water-conducting fractured zones in coal seams, incorrect conclusions can be drawn because of electrical anisotropy within the water-conducting fractured zones. We present, in this paper, a new geo-electrical model based on the geology of water-conducting fractured zones in coal seams. Factors that influence electrical anisotropy were analyzed, including formation water resistivity, porosity, fracture density, and fracture surface roughness, pressure, and dip angle. Numerical simulation was used to evaluate the proposed electrical method. The results demonstrate a closed relationship between the shape of apparent resistivity and the strike and dip of a fracture. Hence, the findings of this paper provide a practical resistivity method for coal-mining production.

  15. Chaotic Zones around Rotating Small Bodies

    Energy Technology Data Exchange (ETDEWEB)

    Lages, José; Shevchenko, Ivan I. [Institut UTINAM, Observatoire des Sciences de l’Univers THETA, CNRS, Université de Franche-Comté, Besançon F-25030 (France); Shepelyansky, Dima L., E-mail: jose.lages@utinam.cnrs.fr [Laboratoire de Physique Théorique du CNRS, IRSAMC, Université de Toulouse, UPS, Toulouse F-31062 (France)

    2017-06-01

    Small bodies of the solar system, like asteroids, trans-Neptunian objects, cometary nuclei, and planetary satellites, with diameters smaller than 1000 km usually have irregular shapes, often resembling dumb-bells or contact binaries. The spinning of such a gravitating dumb-bell creates around it a zone of chaotic orbits. We determine its extent analytically and numerically. We find that the chaotic zone swells significantly if the rotation rate is decreased; in particular, the zone swells more than twice if the rotation rate is decreased 10 times with respect to the “centrifugal breakup” threshold. We illustrate the properties of the chaotic orbital zones in examples of the global orbital dynamics about asteroid 243 Ida (which has a moon, Dactyl, orbiting near the edge of the chaotic zone) and asteroid 25143 Itokawa.

  16. Surf zone flushing on embayed beaches

    Science.gov (United States)

    Castelle, Bruno; Coco, Giovanni

    2013-05-01

    Abstract Using a numerical model, we show that the surf zone of embayed beaches systematically flushes out more floating material (simulated using passive tracers) than on open beaches, with most exits occurring through the headland rips. For obliquely incident waves, a headland rip acts as a persistent conduit for transporting floating material out of the surf zone and into the inner shelf region. Wave angle and embayment size determine which headland rip (upwave or downwave) flushes out more the surf zone material. For narrow embayed beaches, passive drifters exit the surf zone through the upwave headland rip. For wider embayed beaches, the longshore current has enough room to develop and is further deflected against the downwave headland where most drifters exit the surf zone. Our results indicate that wave-exposed rugged coasts strongly enhance exchange of floating matter (e.g., pollutants and nutrients) at the ocean/continent interface.

  17. UV Habitable Zones Further Constrain Possible Life

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Where should we search for life in the universe? Habitable zones are traditionallydetermined based on the possibility of liquid water existing on a planet but ultraviolet (UV) radiation also plays a key role.The UV Habitable ZoneSchematic showing how the traditional habitable zones location and width changes around different types of stars. The UV habitable zone also hasdifferent locations and widths depending on the mass and metallicity of the star. [NASA/Kepler Mission/Dana Berry]Besides the presence of liquid water, there are other things life may need to persist. For life as we know it, one important elementis moderate UV radiation: if a planet receives too little UV flux, many biological compounds cant be synthesized. If it receives too much, however, then terrestrial biological systems (e.g. DNA) can be damaged.To determinethe most likely place to findpersistent life, we should therefore look for the region where a stars traditional habitable zone, within which liquid water is possible, overlaps with its UV habitable zone, within which the UV flux is at the right level to support life.Relationship between the stellar mass and location of the boundaries of the traditional and UV habitable zones for a solar-metallicity star. din and dout denote inner and outer boundaries, respectively. ZAMS and TMS denote when the star joins and leaves the main sequence, respectively. The traditional and UV habitable zones overlap only for stars of 11.5 solar masses. [Adapted from Oishi and Kamaya 2016]Looking for OverlapIn a recent study, two scientists from the National Defense Academy of Japan, Midori Oishi and Hideyuki Kamaya, explored howthe location of this UV habitable zone and that of its overlap with the traditional habitable zone might be affected by a stars mass and metallicity.Oishi and Kamaya developed a simple evolutional model of the UV habitable zone in stars in the mass range of 0.084 solar masses with metallicities of roughly solar metallicity (Z=0.02), a

  18. Pseudotransition zone in long segment Hirschsprung's disease

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.F.; Cronk, R.L.

    1980-01-01

    Two cases of Hirschsprung's disease with pseudotransition zones are presented. The location and appearance of the transition zone, transverse contractions proximal to the radiographic transition zone, and a delayed film aid in distinguishing a false transition zone from a true transition zone.

  19. Towards sustainable coexistence of aquaculture and fisheries in the coastal zone

    DEFF Research Database (Denmark)

    Bergh, Øjvind; Gomez, Emma Bello; Børsheim, Knut Yngve

    2012-01-01

    Globally, coastal areas are subject to an increase in competing activities. Coastal fisheries and aquaculture are highly dependent on availability and accessibility of appropriate sites. Aquaculture production is increasing, whereas fisheries are at best stagnant. Coastal activities also include ......, both industries represent human activities strongly influencing, and influenced by, the environment. Management of aquaculture and fisheries, as well as other uses of the coastal zone, should be considered integral parts with local variations in their respective importance....

  20. Using purposeful landscape zoning of Ukraine to improve soil protection system

    Directory of Open Access Journals (Sweden)

    Володимир Тишковець

    2016-10-01

    Full Text Available Basic aspects of Ukrainian landscapes target zoning use for maintenance of soil protection system on agricultural lands have been presented. The analysis of current systems of purposeful zoning of territories in the country and modern approaches to its modernization has been done. The ameliorative functions of forest in accordance with existing main and supportive negative factors, forms and intensiveness of its appearance in concrete types of landscapes have been explained. The questions of forest projection optimization in accordance with natural-climatic conditions of certain regions have been described. The ways of qualitative new use of agroforest ameliorative measures have been determined. The new zoning system on the basis of main soil erosion factors principally differs from the previous systems. The proposed zoning method is characterized by complexity, involving main physical, geographical and agricultural factors in the order of their impact on soil erosion processes. These factors consist of climate (water and temperature regime, relief and character of agricultural use of territory. Meanwhile, other factors (soil, vegetative cover and other are used simultaneously with the main factors. That kind of zoning by the main factors of soil erosion is only the first stage. The second stage should be zoning by types of systems of counter erosion measures. In this article the authors have shown that when choosing agrarian ameliorative methods, the influence on negative factors on agriculture should be considered in the new zoning of the territory. A number of references and fund materials, including those of territorial zoning have been analyzed in the article. Preferences and negative aspects as well as selection of a basis for new agrarian ameliorative zoning of Ukrainian landscapes which includes the full information of factors and conditions of formation and expansion of negative factors for agriculture have been proposed.

  1. Better recovery with positive zone separation

    Energy Technology Data Exchange (ETDEWEB)

    Henry, J.C.

    1976-04-01

    A common practice in wells drilled 20 to 30 yr ago was to perforate all the zones at one time and to frac them at the same time. When the ultimate recovery from a well treated in this manner was compared with offset wells producing from only one zone, it was found that the offset wells often did better. One possible reason is that the poor zones stole all the frac treatment from the good zones. The Spraberry Trend field of W. Texas is approx. 100 miles x 20 miles and contains several thousand wells. Distance from the top of the Spraberry Formation to the base of the Dean in the Spraberry Trend field is 1,700 ft, which contains as many as 20 to 30 different sand stringers or zones. Four primary means of separating the various zones in the Spraberry-Dean are frac bomb, pressure differential, ball sealers, and bridge plug. The frac bomb method is the most popular. It consists of running a frac baffle in the casing string. The baffle, which fits between 2 joints of casing in the collar, has a slightly smaller inside diameter than the casing so that a bomb dropped into the casing will seat in the baffle. Generally, a combination of 2 or more of these techniques is used to separate the zones in the Spraberry-Dean.

  2. Inorganic carbon fluxes across the vadose zone of planted and unplanted soil mesocosms

    DEFF Research Database (Denmark)

    Thaysen, Eike Marie; Jacques, D.; Jessen, S.

    2014-01-01

    The efflux of carbon dioxide (CO2) from soils influences atmospheric CO2 concentrations and thereby climate change. The partitioning of inorganic carbon (C) fluxes in the vadose zone between emission to the atmosphere and to the groundwater was investigated to reveal controlling underlying mechan...

  3. External causes of euro zone inflation differentials : A re-examniation of the evidence

    NARCIS (Netherlands)

    Arnold, I.J.M.; Verhoef, B.

    2004-01-01

    This article focuses on external causes of Euro Zone inflation differential. Persistent inflation differences may influence inflationary expectations and can amplify regional business cycles. With a uniform nominal interest rate, the domestic real interest rates will be lower in high inflation

  4. A Groundwater Model to Assess Water Resource Impacts at the Imperial East Solar Energy Zone

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John [Argonne National Lab. (ANL), Argonne, IL (United States); Greer, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); O' Connor, Ben L. [Argonne National Lab. (ANL), Argonne, IL (United States); Tompson, Andrew F.B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-12-01

    The purpose of this study is to develop a groundwater flow model to examine the influence of potential groundwater withdrawal to support the utility-scale solar energy development at the Imperial East Solar Energy Zone (SEZ) as a part of the Bureau of Land Management’s (BLM) solar energy program.

  5. A Groundwater Model to Assess Water Resource Impacts at the Brenda Solar Energy Zone

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John [Argonne National Lab. (ANL), Argonne, IL (United States); Carr, Adrianne E. [Argonne National Lab. (ANL), Argonne, IL (United States); Greer, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Bowen, Esther E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-12-01

    The purpose of this study is to develop a groundwater flow model to examine the influence of potential groundwater withdrawal to support utility-scale solar energy development at the Brenda Solar Energy Zone (SEZ), as a part of the Bureau of Land Management’s (BLM’s) Solar Energy Program.

  6. 33 CFR 165.1315 - Safety Zones: Fireworks displays in the Captain of the Port Portland Zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zones: Fireworks displays... Coast Guard District § 165.1315 Safety Zones: Fireworks displays in the Captain of the Port Portland Zone. (a) Safety zones. The following areas are designated safety zones: (1) Cinco de Mayo Fireworks...

  7. 77 FR 66072 - Designation of New Grantee; Foreign Trade Zone 66, Wilmington, NC, and Foreign-Trade Zone 67...

    Science.gov (United States)

    2012-11-01

    ... Foreign-Trade Zones Board Designation of New Grantee; Foreign Trade Zone 66, Wilmington, NC, and Foreign-Trade Zone 67, Morehead City, NC Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as amended (19 U.S.C. 81a-81u), and the Foreign-Trade Zones Board Regulations (15 CFR part 400...

  8. Static stress transfers in the Pamir Hindu Kush seismic zone

    Science.gov (United States)

    Sarkar, I.; Sanyal, S.

    2004-08-01

    The possible influence of static stress transfers on the moderate and small earthquake activity within the Pamir Hindu Kush seismic zone, in the brittle contact zone where the Indian and Eurasian lithospheric plates interact, is investigated. We consider 129 small and moderate earthquakes that occurred in this region between 1960 and 2002. We assume that these earthquakes were caused mainly by normal frictional sliding processes and that, to a first order of approximation, the rates of stress/strain accumulation in the elastico-viscous upper mantle rocks here are constant in time. We compute Coulomb failure stresses that were transferred from these earthquakes to other prestressed earthquake faults of the region. The computed positive/negative static stress transfers are often cumulatively large enough to suggest significant promotion/inhibition of future small and moderate earthquake activity here. Our analysis suggests that, in the region of investigation, transferred static stresses significantly modulate the ambient stress field, influencing the moderate and small earthquake activity here in an important way.

  9. Hydrogen isotope accumulation in the helium implantation zone in tungsten

    Science.gov (United States)

    Markelj, S.; Schwarz-Selinger, T.; Založnik, A.

    2017-06-01

    The influence of helium (He) on deuterium (D) transport and retention was studied experimentally in tungsten (W). Helium was implanted 1 µm deep into W to a maximum calculated concentration of 3.4 at.%. To minimize the influence of displacement damage created during the He implantation on D retention, so-called self-damaged W was used. W was damaged by 20 MeV W ion bombardment and defects were populated by low-temperature D plasma at room temperature before He implantation. Deuterium depth profiling was performed in situ during isochronal annealing in the temperature range from 300 K to 800 K. It is shown for the first time unambiguously that He attracts D and locally increases D trapping. Deuterium retention increased by a factor of two as compared to a non-He implanted W reference after sample annealing at 450 K. Rate equation modelling can explain the measured D depth profiles quantitatively when keeping the de-trapping parameters unchanged but only increasing the number of traps in the He zone. This bolsters the confidence in the theoretical calculations predicting that more hydrogen isotopes can be stored around a He cluster zone.

  10. Unravelling Diurnal Asymmetry of Surface Temperature in Different Climate Zones.

    Science.gov (United States)

    Vinnarasi, R; Dhanya, C T; Chakravorty, Aniket; AghaKouchak, Amir

    2017-08-04

    Understanding the evolution of Diurnal Temperature Range (DTR), which has contradicting global and regional trends, is crucial because it influences environmental and human health. Here, we analyse the regional evolution of DTR trend over different climatic zones in India using a non-stationary approach known as the Multidimensional Ensemble Empirical Mode Decomposition (MEEMD) method, to explore the generalized influence of regional climate on DTR, if any. We report a 0.36 °C increase in overall mean of DTR till 1980, however, the rate has declined since then. Further, arid deserts and warm-temperate grasslands exhibit negative DTR trends, while the west coast and sub-tropical forest in the north-east show positive trends. This transition predominantly begins with a 0.5 °C increase from the west coast and spreads with an increase of 0.25 °C per decade. These changes are more pronounced during winter and post-monsoon, especially in the arid desert and warm-temperate grasslands, the DTR decreased up to 2 °C, where the rate of increase in minimum temperature is higher than the maximum temperature. We conclude that both maximum and minimum temperature increase in response to the global climate change, however, their rates of increase are highly local and depend on the underlying climatic zone.

  11. Geometry of the Aegean Benioff zones

    Directory of Open Access Journals (Sweden)

    M. Knapmeyer

    1999-06-01

    Full Text Available The morphology of the Aegean Benioff zone was reconstructed using 1366 hypocentres from the PDE catalogue 1973-1997. Two such zones are identified under the Aegean area, a large one (Main Aegean Subduction, MAS spanning the whole Hellenic arc and a smaller and younger one under the Western Peloponnesus. The geometry of the MAS suggests that it blocks its own subduction and, therefore, causes the development of the smaller western zone as a result of a step back process in the Pliocene.

  12. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-10-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalised lens volume and the main lens and recharge characteristics, enabling an empirical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase and the increase of recharge frequency causes a decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the centre of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens

  13. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    Science.gov (United States)

    Eeman, S.; van der Zee, S. E. A. T. M.; Leijnse, A.; de Louw, P. G. B.; Maas, C.

    2012-10-01

    In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalised lens volume and the main lens and recharge characteristics, enabling an empirical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase and the increase of recharge frequency causes a decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the centre of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens characteristics using

  14. Response to recharge variation of thin lenses and their mixing zone with underlying saline groundwater

    Science.gov (United States)

    Eeman, S.; van der Zee, S. E. A. T. M.; Leijnse, A.; de Louw, P. G. B.; Maas, C.

    2012-01-01

    In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalized lens volume and the main lens and recharge characteristics, enabling an analytical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase, and increase of recharge frequency causes decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the center of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens characteristics using basic

  15. Microstructure and mechanical properties of hard zone in friction stir welded X80 pipeline steel relative to different heat input

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Hakan, E-mail: hakanay@uludag.edu.tr [Engineering and Architecture Faculty, Mechanical Engineering Department, Uludag University, 16059 Gorukle-Bursa (Turkey); Nelson, Tracy W. [Mechanical Engineering Department, Brigham Young University, 435 CTB, Provo, UT 84602 (United States)

    2013-12-01

    The study was conducted to investigate the microstructure and mechanical properties of the hard zone in friction stir welded X80 pipeline steel at different heat inputs. Microstructural analysis of the welds was carried out using optical microscopy, transmission electron microscopy, and microhardness. Heat input during friction stir welding process had a significant influence on the microstructure and mechanical properties in the hard zone along the advancing side of the weld nugget. Based on the results, the linear relationships between heat input and post-weld microstructures and mechanical properties in the hard zone of friction stir welded X80 steels were established. It can be concluded that with decrease in heat input the bainitic structure in the hard zone becomes finer and so hard zone strength increases.

  16. Using Multicriteria Decision Making Techniques in Free Zone for Facility Location Selection: An Example for Eastern Anatolia Region

    Directory of Open Access Journals (Sweden)

    Gökhan Ağaç

    2015-06-01

    Full Text Available Free Zones contribute to the prosperity of the region by increasing employment, attracting foreign capital, allowing technology transfer and increasing exports. In this study, an application of location selection was performed for a possible Free Zone established in provinces of Eastern Anatolia Region. For application of the study, AHP, TOPSIS, VIKOR and ELECTRE, which are multi criteria decision making techniques, were used. AHP was used for determine weights of the criteria that influence the Free Zone location selection while TOPSIS, VIKOR and ELECTRE methods were used to rank alternatives. Accordingly; the three most important criteria for the Free Zone location selection were proximity countries, quantity of exports and government incentives while first three provinces were respectively, Iğdır, Hakkâri and Van for Free Zone will be established.

  17. Synthesis of work-zone performance measures.

    Science.gov (United States)

    2013-09-01

    The main objective of this synthesis was to identify and summarize how agencies collect, analyze, and report different work-zone : traffic-performance measures, which include exposure, mobility, and safety measures. The researchers also examined comm...

  18. WVSAMB Color Digital Orthophotos North Zone

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Digital color orthophotography of the State of West Virginia (West Virginia State Plane Coordinate System North Zone). The W.V. state plane system has two...

  19. Seismic coupling and uncoupling at subduction zones

    Science.gov (United States)

    Ruff, L.; Kanamori, H.

    1983-01-01

    Some of the correlations concerning the properties of subduction zones are reviewed. A quantitative global comparison of many subduction zones reveals that the largest earthquakes occur in zones with young lithosphere and fast convergence rates. Maximum earthquake size is directly related to the asperity distribution on the fault plane. This observation can be translated into a simple model of seismic coupling where the horizontal compressive stress between two plates is proportional to the ratio of the summed asperity area to the total area of the contact surface. Plate age and rate can control asperity distribution directly through the horizontal compressive stress associated with the vertical and horizontal velocities of subducting slabs. The basalt to eclogite phase change in the down-going oceanic crust may be largely responsible for the uncoupling of subduction zones below a depth of about 40 km.

  20. Global challenges in integrated coastal zone management

    DEFF Research Database (Denmark)

    Growing pressure from increasingly diverse human activities coupled with climate change impacts threaten the functional integrity of coastal ecosystems around the globe. A multi-disciplinary approach towards understanding drivers, pressures and impacts in the coastal zone requires effective...... integration of data and information in policy and management, combining expertise from nature and social science, to reach a balanced and sustainable development of the coastal zone. This important book comprises the proceedings of The International Symposium on Integrated Coastal Zone Management, which took...... place in Arendal, Norway between 3-7 July 2011. The main objective of the Symposium was to present current knowledge and to address issues on advice and management related to the coastal zone. The major themes of papers included in this book are: Coastal habitats and ecosystem services Adaptation...

  1. 78 FR 15883 - Standard Time Zone Boundaries

    Science.gov (United States)

    2013-03-13

    ... reference from eight to nine. Likewise, in Sec. 71.1(c), the ninth time zone, Chamorro, is added to the list... 1966, are Atlantic, eastern, central, mountain, ] Pacific, Alaska, Hawaii-Aleutian, Samoa, and Chamorro...

  2. EPA Region 1 No Discharge Zones

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset details No Discharge Zones (NDZ) for New England. Boaters may not discharge waste into these areas. Boundaries were determined mostly by Federal...

  3. 46 CFR 76.27-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... zones to restrict the area covered by any particular alarm signal. (b) All spaces in a fire detecting... of not more than 3,000 square feet. (2) Isolated rooms or lockers in such spaces as mast houses...

  4. 46 CFR 76.30-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... zones to restrict the area covered by any particular alarm signal. (b) All spaces in a fire detecting... not more than 3,000 feet. (2) Isolated rooms or lockers in such spaces as mast houses, wheelhouse top...

  5. Advanced Vadose Zone Simulations Using TOUGH

    Energy Technology Data Exchange (ETDEWEB)

    Finsterle, S.; Doughty, C.; Kowalsky, M.B.; Moridis, G.J.; Pan,L.; Xu, T.; Zhang, Y.; Pruess, K.

    2007-02-01

    The vadose zone can be characterized as a complex subsurfacesystem in which intricate physical and biogeochemical processes occur inresponse to a variety of natural forcings and human activities. Thismakes it difficult to describe, understand, and predict the behavior ofthis specific subsurface system. The TOUGH nonisothermal multiphase flowsimulators are well-suited to perform advanced vadose zone studies. Theconceptual models underlying the TOUGH simulators are capable ofrepresenting features specific to the vadose zone, and of addressing avariety of coupled phenomena. Moreover, the simulators are integratedinto software tools that enable advanced data analysis, optimization, andsystem-level modeling. We discuss fundamental and computationalchallenges in simulating vadose zone processes, review recent advances inmodeling such systems, and demonstrate some capabilities of the TOUGHsuite of codes using illustrative examples.

  6. VT New Market Tax Credit - Hot Zones

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The EconOther_NMTC layer delineates New Market Tax Credit (NMTC) "hot zones" and qualified counties and census tracts. This dataset is designed to...

  7. Vadose Zone Transport Field Study: Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Gee, Glendon W.; Ward, Anderson L.

    2001-11-30

    Studies were initiated at the Hanford Site to evaluate the process controlling the transport of fluids in the vadose zone and to develop a reliable database upon which vadose-zone transport models can be calibrated. These models are needed to evaluate contaminant migration through the vadose zone to underlying groundwaters at Hanford. A study site that had previously been extensively characterized using geophysical monitoring techniques was selected in the 200 E Area. Techniques used previously included neutron probe for water content, spectral gamma logging for radionuclide tracers, and gamma scattering for wet bulk density. Building on the characterization efforts of the past 20 years, the site was instrumented to facilitate the comparison of nine vadose-zone characterization methods: advanced tensiometers, neutron probe, electrical resistance tomography (ERT), high-resolution resistivity (HRR), electromagnetic induction imaging (EMI), cross-borehole radar (XBR), and cross-borehole seismic (XBS). Soil coring was used to obtain soil samples for analyzing ionic and isotopic tracers.

  8. Vulnerable Zone Indicator System (Option 2)

    Science.gov (United States)

    Enter your latitude and longitude to access the Vulnerable Zone Indicator System. VZIS can help you determine if your area could be affected by a chemical accident at a facility that submitted a Risk Management Plan (RMP).

  9. Calculating Buffer Zones: A Guide for Applicators

    Science.gov (United States)

    Buffer zones provide distance between the application block (i.e., edge of the treated field) and bystanders, in order to control pesticide exposure risk from soil fumigants. Distance requirements may be reduced by credits such as tarps.

  10. Global challenges in integrated coastal zone management

    DEFF Research Database (Denmark)

    place in Arendal, Norway between 3-7 July 2011. The main objective of the Symposium was to present current knowledge and to address issues on advice and management related to the coastal zone. The major themes of papers included in this book are: Coastal habitats and ecosystem services Adaptation...... integration of data and information in policy and management, combining expertise from nature and social science, to reach a balanced and sustainable development of the coastal zone. This important book comprises the proceedings of The International Symposium on Integrated Coastal Zone Management, which took....../mitigation to change in coastal systems Coastal governance Linking science and management Comprising a huge wealth of information, this timely and well-edited volume is essential reading for all those involved in coastal zone management around the globe. All libraries in research establishments and universities where...

  11. Work zone performance monitoring application development.

    Science.gov (United States)

    2016-10-01

    The Federal Highway Administration (FHWA) requires state transportation agencies to (a) collect and analyze safety and mobility data to manage the work zone impacts of individual projects during construction and (b) improve overall agency processes a...

  12. Adaptation aux changements climatiques dans les zones ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    La croissance rapide des zones périurbaines de l'Asie du Sud-Est est caractérisée par un manque de services de base, des milieux bâtis non planifiés et la relative faiblesse des gouvernements. Les habitants de ces zones sont particulièrement vulnérables face aux phénomènes climatiques extrêmes tels que les ouragans ...

  13. Treating nahcolite containing formations and saline zones

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J

    2013-06-11

    A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

  14. U-PLANT GEOGRAPHIC ZONE CLEANUP PROTOTYPE

    Energy Technology Data Exchange (ETDEWEB)

    ROMINE, L.D.

    2006-02-01

    The U Plant geographic zone (UPZ) occupies 0.83 square kilometers on the Hanford Site Central Plateau (200 Area). It encompasses the U Plant canyon (221-U Facility), ancillary facilities that supported the canyon, soil waste sites, and underground pipelines. The UPZ cleanup initiative coordinates the cleanup of the major facilities, ancillary facilities, waste sites, and contaminated pipelines (collectively identified as ''cleanup items'') within the geographic zone. The UPZ was selected as a geographic cleanup zone prototype for resolving regulatory, technical, and stakeholder issues and demonstrating cleanup methods for several reasons: most of the area is inactive, sufficient characterization information is available to support decisions, cleanup of the high-risk waste sites will help protect the groundwater, and the zone contains a representative cross-section of the types of cleanup actions that will be required in other geographic zones. The UPZ cleanup demonstrates the first of 22 integrated zone cleanup actions on the Hanford Site Central Plateau to address threats to groundwater, the environment, and human health. The UPZ contains more than 100 individual cleanup items. Cleanup actions in the zone will be undertaken using multiple regulatory processes and decision documents. Cleanup actions will include building demolition, waste site and pipeline excavation, and the construction of multiple, large engineered barriers. In some cases, different cleanup actions may be taken at item locations that are immediately adjacent to each other. The cleanup planning and field activities for each cleanup item must be undertaken in a coordinated and cohesive manner to ensure effective execution of the UPZ cleanup initiative. The UPZ zone cleanup implementation plan (ZCIP) was developed to address the need for a fundamental integration tool for UPZ cleanup. As UPZ cleanup planning and implementation moves forward, the ZCIP is intended to be a living

  15. Oil and gas fields - transfer zone relationships, Thrace basin, NW Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Coskun, B. [Ankara Univ. (Turkey). Geology Dept.

    1997-06-01

    In the Thrace basin, oil and gas are produced from carbonate and sandstone reservoirs of Eocene and Oligocene age. Detailed geological and geophysical studies reveal that earlier and Eocene structures were influenced by basement paleotopography resulting from late Cretaceous movements between the Arabian and Anatolian plates while latest Miocene structures were generated by splays of the North Anatolian Fault in the Thrace basin. The Eocene structures, which contain the Hamitabat gas and Devecatagi and K. Osmancik oil fields, trend in a NE-SW direction. However, Miocene structures which are gas producers in the Karacaoglan and Umurca fields are oriented in a NW-SE direction, parallel to the strike of the main faults which accommodate the transfer zones in the Thrace basin. The transfer zones occur between faults that dip in opposite directions (conjugate) and in the same directions (synthetic). The formation of reservoir zones, improvement of reservoir characteristics and generation of oil and gas in the oil window zone were influenced by the timing of faulting and appearance of the transfer zones in the Thrace basin. (author)

  16. Analysis of the heat affected zone in CO2 laser cutting of stainless steel

    Directory of Open Access Journals (Sweden)

    Madić Miloš J.

    2012-01-01

    Full Text Available This paper presents an investigation into the effect of the laser cutting parameters on the heat affected zone in CO2 laser cutting of AISI 304 stainless steel. The mathematical model for the heat affected zone was expressed as a function of the laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position using the artificial neural network. To obtain experimental database for the artificial neural network training, laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of the cutting parameter. Using the 27 experimental data sets, the artificial neural network was trained with gradient descent with momentum algorithm and the average absolute percentage error was 2.33%. The testing accuracy was then verified with 6 extra experimental data sets and the average predicting error was 6.46%. Statistically assessed as adequate, the artificial neural network model was then used to investigate the effect of the laser cutting parameters on the heat affected zone. To analyze the main and interaction effect of the laser cutting parameters on the heat affected zone, 2-D and 3-D plots were generated. The analysis revealed that the cutting speed had maximum influence on the heat affected zone followed by the laser power, focus position and assist gas pressure. Finally, using the Monte Carlo method the optimal laser cutting parameter values that minimize the heat affected zone were identified.

  17. Subduction of fracture zones controls mantle melting and geochemical signature above slabs.

    Science.gov (United States)

    Manea, Vlad C; Leeman, William P; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-10-24

    For some volcanic arcs, the geochemistry of volcanic rocks erupting above subducted oceanic fracture zones is consistent with higher than normal fluid inputs to arc magma sources. Here we use enrichment of boron (B/Zr) in volcanic arc lavas as a proxy to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent fracture zones in the relatively cool Aleutian and Andean subduction zones where fracture zone subduction locally enhances fluid introduction beneath volcanic arcs. Geodynamic models of subduction have not previously considered how fracture zones may influence the melt and fluid distribution above slabs. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that enhanced production of slab-derived fluids and mantle wedge melts concentrate in areas where fracture zones are subducted, resulting in significant along-arc variability in magma source compositions and processes.

  18. Dual-hormone stress reactivity predicts downstream war-zone stress-evoked PTSD.

    Science.gov (United States)

    Josephs, Robert A; Cobb, Adam R; Lancaster, Cynthia L; Lee, Han-Joo; Telch, Michael J

    2017-04-01

    The crucial role of the hypothalamic-pituitary-adrenal axis (HPA) in stress-related homeostasis suggests dysregulated HPA involvement in the pathogenesis of post-traumatic stress disorder (PTSD), yet most studies examining linkages between HPA axis measures and PTSD have yielded null findings. One untested explanation for this inconsistency is a failure to account for simultaneous adrenal and gonadal influence. Here we tested the singular and interactive effects of cortisol (CR) and testosterone (TR) reactivity as moderators of war-zone stress evoked PTSD emergence in the war-zone. U.S. soldiers (N=120) scheduled for deployment to Iraq completed pre-deployment measures of CR and TR stress reactivity to a CO2 inhalation challenge. Once deployed, monthly assessments of exposure to traumatic war-zone stressors and PTSD symptoms were collected via a web-based assessment system. Cortisol hypo-reactivity potentiated the pathogenic impact of war-zone stressors only in soldiers for whom the CO2 challenge did not elevate testosterone, suggesting that the dual hormone stress reactivity profile of blunted cortisol and testosterone may confer increased risk for PTSD emergence by potentiating the pathogenic effects of war-zone stressors. Findings underscore the utility of assessing both HPA and HPG stress reactivity when assessing PTSD vulnerability and may help inform efforts for enhanced soldier screening and inoculation to war-zone stressors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Seismic evidence for a possible deep crustal hot zone beneath Southwest Washington

    Science.gov (United States)

    Flinders, Ashton; Shen, Yang

    2017-01-01

    Crustal pathways connecting deep sources of melt and the active volcanoes they supply are poorly understood. Beneath Mounts St. Helens, Adams, and Rainier these pathways connect subduction-induced ascending melts to shallow magma reservoirs. Petrogenetic modeling predicts that when these melts are emplaced as a succession of sills into the lower crust they generate deep crustal hot zones. While these zones are increasingly recognized as a primary site for silicic differentiation at a range of volcanic settings globally, imaging them remains challenging. Near Mount Rainier, ascending melt has previously been imaged ~28 km northwest of the volcano, while to the south, the volcano lies on the margin of a broad conductive region in the deep crust. Using 3D full-waveform tomography, we reveal an expansive low-velocity zone, which we interpret as a possible hot zone, linking ascending melts and shallow reservoirs. This hot zone may supply evolved magmas to Mounts St. Helens and Adams, and possibly Rainier, and could contain approximately twice the melt volume as the total eruptive products of all three volcanoes combined. Hot zones like this may be the primary reservoirs for arc volcanism, influencing compositional variations and spatial-segmentation along the entire 1100 km-long Cascades Arc.

  20. Starting Points for Planning Business Zones in Slovenia in the Post-independence Period

    Directory of Open Access Journals (Sweden)

    Čok Gregor

    2016-01-01

    Full Text Available In Slovenia, during the period of transition practically all mechanisms for steering economic and spatial development changed. The planning of business zones is part of this framework; business zones are competitive business environments for the placement of economic activities in the physical space. Over the past 25 years, their design was influenced by various factors: introduction of free market principles, privatisation of social property, and interests of the young state to establish, using proper strategies and financial initiatives, an efficient network of zones as drivers of economic development. Despite the ambitious plans and adopted strategic spatial planning acts at the national level we nowadays find that the zones, in their current spatial and administrative form, are not an efficient enough development mechanism. The focus of the study was to define the starting points as the basis for planning business zones and shaping policies to improve the existing situation. To improve the business competitiveness of the existing zones and their role in the planning and design system, we will have to set up a more efficient data updating system and form a broader approach to their management, promotion, and marketing.

  1. Aspheric Optical Zones: The Effective Optical Zone with the SCHWIND AMARIS.

    Science.gov (United States)

    Camellin, Massimo; Arba Mosquera, Samuel

    2011-02-01

    To evaluate the effective optical zone (the part of the ablation that receives full correction) among eyes that underwent laser epithelial keratomileusis (LASEK)/epi-LASEK treatments for myopic astigmatism. Twenty LASEK/epi-LASEK treatments with a mean spherical equivalent refraction (SE) of -5.49±2.35 diopters (D) performed using the SCHWIND AMARIS system were retrospectively evaluated at 6-month follow-up. In all cases, pre- and postoperative corneal wavefront analyses were performed with the Keratron Scout (OPTIKON 2000). Effective optical zone values were evaluated from the changes of root-mean-square (RMS) of higher order wavefront aberration (ΔRMSho), spherical aberration (ΔSphAb), and RMS of the change of higher order wavefront aberration (RMS[ΔHOAb]). Correlations of effective optical zone with planned optical zone and SE correction were analyzed using a bilinear function as well as calculations of the isometric lines for which effective optical zone equals planned optical zone and of the nomogram planned optical zone to achieve an intended effective optical zone. At 6 months, SE was -0.05±0.43 D, with 90% of eyes within ±0.50 D. Mean higher order wavefront aberration RMS increased 0.12 μm, spherical aberration 0.09 μm, and coma 0.04 μm after treatment (6-mm diameter). Mean planned optical zone was 6.76±0.25 mm, whereas mean EOZ(ΔRMSho) was 6.74±0.66 mm (bilinear correlation P6.75 mm result in effective optical zones at least as large as planned optical zones. For optical zones <6.75 mm, a nomogram should be applied. Copyright 2011, SLACK Incorporated.

  2. The Influence of Rocky Reefs on Structure of Benthic Macrofauna in Nearby Soft-sediments

    Science.gov (United States)

    Barros, F.; Underwood, A. J.; Lindegarth, M.

    2001-02-01

    Influences of rocky reefs on composition and abundances of species in assemblages of macrofauna in nearby subtidal, soft-sediments were examined by sampling at three distances from four rocky reefs, three natural and one man-made, in Botany Bay, NSW, Australia. There was significant spatial variation in structure of assemblages between transects and among reefs. The proportion of coarse material in sediments was generally larger close to, than far from, reefs. Assemblages sampled close to reefs were generally different in structure from those sampled away from rocky reefs. In multivariate analyses, assemblages close to reefs were spatially more variable than were those far from reefs. Analyses demonstrated that there were more species close to, than far from, the reefs; polychaetes of the family Syllidae were more abundant far from, than near to, rocky reefs. Artificial and natural rocky reefs influenced nearby benthic assemblages in sediments and various models are discussed to explain the patterns detected, especially those concerning predation and characteristics of the sediments.

  3. Tracing the Paleo sulfate-methane transition zones and H2S seepage events in marine sediments: An application of C-S-Mo systematics

    Digital Repository Service at National Institute of Oceanography (India)

    Peketi, A.; Mazumdar, A.; Joshi, R.K.; Patil, D.J.; Srinivas, P.L.; Dayal, A.M.

    Microbially mediated anaerobic oxidation of methane (AOM) coupled with sulfate consumption within the sulfate methane transition zone (SMTZ) in marine sediments is a widely recorded biogeochemical reaction and has profound influence...

  4. Material-property zones used in the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Zones in this data set represent spatially contiguous areas that influence ground-water flow in the Death Valley regional ground-water flow system (DVRFS), an...

  5. Geophysical Limitations on the Habitable Zone: Volcanism and Plate Tectonics

    Science.gov (United States)

    Noack, Lena; Rivoldini, Attilio; Van Hoolst, Tim

    2016-04-01

    Planets are typically classified as potentially life-bearing planets (i.e. habitable planets) if they are rocky planets and if a liquid (e.g. water) could exist at the surface. The latter depends on several factors, like for example the amount of available solar energy, greenhouse effects in the atmosphere and an efficient CO2-cycle. However, the definition of the habitable zone should be updated to include possible geophysical constraints, that could potentially influence the CO2-cycle. Planets like Mars without plate tectonics and no or only limited volcanic events can only be considered to be habitable at the inner boundary of the habitable zone, since the greenhouse effect needed to ensure liquid surface water farther away from the sun is strongly reduced. We investigate if the planet mass as well as the interior structure can set constraints on the occurrence of plate tectonics and outgassing, and therefore affect the habitable zone, using both parameterized evolution models [1] and mantle convection simulations [1,2]. We find that plate tectonics, if it occurs, always leads to sufficient volcanic outgassing and therefore greenhouse effect needed for the outer boundary of the habitable zone (several tens of bar CO2), see also [3]. One-plate planets, however, may suffer strong volcanic limitations. The existence of a dense-enough CO2 atmosphere allowing for the carbon-silicate cycle and release of carbon at the outer boundary of the habitable zone may be strongly limited for planets: 1) without plate tectonics, 2) with a large planet mass, and/or 3) a high iron content. Acknowledgements This work has been funded by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office through the Planet Topers alliance, and results within the collaboration of the COST Action TD 1308. References Noack, L., Rivoldini, A., and Van Hoolst, T.: CHIC - Coupling Habitability, Interior and Crust, INFOCOMP 2015, ISSN 2308-3484, ISBN 978

  6. Standardized precipitation index zones for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Giddings, L.; Soto, M. [Instituto de Ecologia, A.C., Xalapa, Veracruz (Mexico); Rutherford, B.M.; Maarouf, A. [Faculty of Environmental Studies, York University, Toronto, Ontario (Canada)

    2005-01-01

    Precipitation zone systems exists for Mexico based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El nino. An empirical set of seven exclusively Mexican and six shared zones was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zones edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed. [Spanish] Existen varios sistemas de zonificacion de Mexico basados en la estacionalidad, cantidad de precipitacion, climas y divisiones geograficas, pero ninguno es conveniente para el estudio de la relacion de la precipitacion con fenomenos tales como El Nino. En este trabajo se presenta un conjunto de siete zonas empiricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imagenes de SPI (Indice Estandarizado de la Precipitacion), desde 1940 a 1989: una serie de 582 imagenes mensuales (SPI-12), una series de 50 imagenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imagenes (SPI-6) de meses de verano

  7. Bathymetric control of surf zone retention on a rip-channelled beach

    Science.gov (United States)

    Castelle, Bruno; Reniers, Ad; MacMahan, Jamie

    2014-08-01

    Simulations from a numerical model address the impact of nearshore morphology on surf zone retention on, open coast, rip-channelled beaches exposed to shore-normal waves. In the model, rip channels are regularly spaced alongshore with a given spacing λ. For a given reference case bathymetry ( λ= 200 m), rip current circulations retain floating material at a hourly rate R of about 80 % which is in line with most existing field and laboratory studies in similar settings. The influence of a surf zone rip-channel morphology on surf zone retention is evaluated by a number of morphologic parameters. Results show that rip spacing is important. The ratio of the surf zone width X s to rip spacing λ controls surf zone retention with R rapidly increasing with increasing X s / λ up to a threshold of about 1 above which R levels off to become asymptotic to 100 %. The impact of the presence of a rip head bar is profound but nonlinear. The onset of wave breaking across the rip head bar drives a weak seaward located circulation providing major pathways for surface water exiting the surf zone compartment. Additional simulations suggest that alongshore variations in the offshore bathymetry are important. Patterns in the wave field enforced by wave refraction and potentially wave breaking across offshore bathymetric anomalies can provide a conduit for transporting floating material out of the surf zone and into the inner shelf region. This has major implications for surf zone flushing by inner-bar rips on multiple-barred beaches and on beaches facing bathymetric anomalies on the inner shelf.

  8. Rockfall events in the European Alps: analysis of topography and permafrost conditions at the detachment zones

    Science.gov (United States)

    Naegeli, Barbara; Nötzli, Jeannette; Fischer, Luzia

    2010-05-01

    The occurrence and changes of permafrost can influence the stability of high mountain rock walls among other factors such as topography, geology or hydrology. Knowledge of the connection between rock fall and permafrost is still limited, but several indications link past rock fall events and the warming of permafrost. For example, observation of numerous rock fall events in the unusually dry and hot summer 2003, the presence of ice in detachment zones, or the demonstrated reduction of shear-strength in ice-filled fractures with warming temperatures. The main objective of the presented study is the analysis of past rock fall staring zones in the European Alps with focus on permafrost and topography in order to learn about the conditions under which such instabilities develop. An inventory of recent rock fall events in the European Alps (mainly the past 100 years) has been established and the collected data has been analysed. The work presented bases on and extends similar earlier studies of rock fall starting zones in permafrost areas. In a first step, a descriptive statistical analysis of topographic and geological characteristics of the detachment zones was conducted and subsequently, the permafrost conditions in the detachment zones were investigated: a) the evaluation of the elevation and the aspect for each detachment zone and the relative comparison with two different permafrost boundary estimations from regional permafrost models, b) the relation of the mean annual air temperature and the potential solar radiation for each detachment zone, c) the assessment of the topographical situation of each detachment zone. Despite uncertainties in the raw data, results corroborate findings from earlier studies that the majority of the rock fall events in the inventory originated from areas with potentially warm permafrost. Interestingly, a large proportion of events originates from areas below ridges and peaks.

  9. Unconventional War and Warfare in the Gray Zone. The New Spectrum of Modern Conflicts

    Directory of Open Access Journals (Sweden)

    Miroslaw Banasik

    2016-06-01

    Full Text Available Experiences of the last couple of years indicate that political objectives are increasingly achieved without official declarations of war. Armed forces are used in untraditional ways and the so-called substitute troops begin to play an increasingly bigger part. The article aims to characterize the conflicts of alternative nature below the level of open war that are on the border between war and peace. The content of the article presents the theory of unconventional warfare and its description, and familiarizes the reader with the concept of grey zone conflicts. It further shows the challenges linked to rivalry for influence zones and security provisions.

  10. Structure of herbivore communities in two oak (Quercus spp.) hybrid zones.

    Science.gov (United States)

    Boecklen, William J; Spellenberg, Richard

    1990-11-01

    We examined patterns of density and species diversity for leaf-mining Lepidopterans and gall-forming Hymenopterans in two oak (Quercus spp.) hybrid zones: Quercus depressipes x Q. rugosa and Q. emoryi x Q. coccolobifolia. In both species complexes, hybrid hosts typically supported significantly lower densities and species diversity of parasites than did parental types. This contradicts the findings of Whitham (1989) that suggested that hybrid hosts may act as parasite sinks both in ecological and evolutionary time. We discuss features of hybrid zones that are likely to influence patterns of herbivory.

  11. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Y.N. [Mexico City Univ. (Mexico). Center for Atmospheric Sciences

    1995-12-31

    Method based on using the pollutant transport equation and the adjoint technique is described here for estimating the pollutant concentration level in ecologically important zones. The method directly relates the pollution level in such zones with the power of the pollution sources and the initial pollution field. Assuming that the wind or current velocities are known (from climatic data or dynamic model), the main and adjoint pollutant transport equations can be considered in a limited area to solve such theoretically and practically important problems as: (1) optimal location of new industries in a given region with the aim to minimize the pollution concentration in certain ecologically important zones, (2) optimization of emissions from operating industries, (3) detection of the plants violating sanitary regulations, (4) analysis of the emissions coming from the vehicle traffic (such emissions can be included in the model by means of the linear pollution sources located along the main roadways), (5) estimation of the oil pollution in various ecologically important oceanic (sea) zones in case of accident with the oil tanker, (6) evaluation of the sea water desalination level in estuary regions, and others. These equations considered in a spherical shell domain can also be applied to the problems of transporting the pollutants from a huge industrial complex, or from the zone of an ecological catastrophe similar to the Chernobyl one

  12. 49 CFR 1105.9 - Coastal Zone Management Act requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Coastal Zone Management Act requirements. 1105.9... ENVIRONMENTAL LAWS § 1105.9 Coastal Zone Management Act requirements. (a) If the proposed action affects land or water uses within a State coastal zone designated pursuant to the Coastal Zone Management Act (16 U.S.C...

  13. 33 CFR 165.755 - Safety Zone; Guayanilla, Puerto Rico

    Science.gov (United States)

    2010-07-01

    ... Zone; Guayanilla, Puerto Rico (a) The following area is established as a safety zone during the... the Eco-Electrica waterfront facility in Guayanilla Bay, Puerto Rico. The safety zone remains in... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; Guayanilla, Puerto...

  14. 27 CFR 28.290 - Receipt in foreign trade zone.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Receipt in foreign trade zone. 28.290 Section 28.290 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... in Foreign-Trade Zone § 28.290 Receipt in foreign trade zone. On receipt at the zone, the shipment...

  15. 33 CFR 2.30 - Exclusive Economic Zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Exclusive Economic Zone. 2.30... JURISDICTION Jurisdictional Terms § 2.30 Exclusive Economic Zone. (a) With respect to the United States... States exercises sovereignty, exclusive economic zone means the zone seaward of and adjacent to the...

  16. 78 FR 75899 - Safety Zone; 2013 Holiday Boat Parades, Captain of the Port Miami Zone; FL

    Science.gov (United States)

    2013-12-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2013 Holiday Boat Parades, Captain of the... establishing two temporary safety zones during the month of December when holiday boat parades are scheduled to... waiting to receive all boat parade event applications to determine if other parades would need a safety...

  17. 78 FR 40396 - Safety Zone; America's Cup Safety Zone and No Loitering Area, San Francisco, CA

    Science.gov (United States)

    2013-07-05

    ... have questions on this rule, call or email Lieutenant Junior Grade William Hawn, U.S. Coast Guard... America's Cup sailing regattas and discuss measures for prevention and response. During this exercise... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; America's Cup Safety Zone and No Loitering...

  18. 75 FR 16370 - Regulated Navigation Areas, Safety Zones, Security Zones; Deepwater Ports in Boston Captain of...

    Science.gov (United States)

    2010-04-01

    ... standards (e.g., specifications of materials, performance, design, or operation; test methods; sampling... do not individually or cumulatively have a significant effect on the human environment. A preliminary... zones for Neptune consist of circular zones, each with a 500-meter radius and centered on each of...

  19. 78 FR 5717 - Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal...

    Science.gov (United States)

    2013-01-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal Concord, CA AGENCY: Coast Guard, DHS. ACTION: Interim rule and... Suisun Bay near Military Ocean Terminal Concord, CA in support of military onload and offload operations...

  20. 75 FR 21990 - Safety Zone; Extended Debris Removal in the Lake Champlain Bridge Construction Zone (Between...

    Science.gov (United States)

    2010-04-27

    ... Champlain Bridge Construction Zone (Between Vermont and New York), Crown Point, NY AGENCY: Coast Guard, DHS... navigable waters immediately surrounding the Lake Champlain Bridge construction zone between Chimney Point... to the north and south of the Lake Champlain Bridge construction site. The Captain of the Port may...

  1. 76 FR 61947 - Safety Zones; Fireworks Displays in Captain of the Port Long Island Sound Zone

    Science.gov (United States)

    2011-10-06

    ... Long Island Sound Zone AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard... Sound Zone. This action is necessary to provide for the safety of life on navigable waters during these... authorized by the COTP Sector Long Island Sound. DATES: This rule is effective in the CFR from October 6...

  2. 77 FR 36396 - Safety Zones; Fireworks Displays in Captain of the Port Long Island Sound Zone

    Science.gov (United States)

    2012-06-19

    ... Long Island Sound Zone AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard...) Long Island Sound Zone. This action is necessary to provide for the safety of life on navigable waters... unless authorized by the COTP Sector Long Island Sound. DATES: This rule is effective from June 23, 2012...

  3. 78 FR 24679 - Safety Zones; Fireworks Displays in Captain of the Port Long Island Sound Zone

    Science.gov (United States)

    2013-04-26

    ... Long Island Sound Zone AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard... (COTP) Long Island Sound (LIS) Zone. This action is necessary to provide for the safety of life on... is prohibited unless authorized by the COTP Sector Long Island Sound. DATES: This rule is effective...

  4. The Geodynamics of Continental Lithosphere Entering a Subduction Zone

    Science.gov (United States)

    Steedman, C. E.; Kaus, B. J.; Becker, T. W.; Okaya, D.; Wu, F. T.

    2006-12-01

    As deformation patterns resulting from subduction of a passive continental margin are insufficiently understood, here we perform 2-D numerical simulations to explore the effects of continental lithosphere entering a subduction zone. The model setup consists of a subduction zone in which the oceanic part of a passive continental margin initially subducts beneath an oceanic plate. A particle-based 2-D visco-elasto-plastic thermo-mechanical finite element code is employed to study the dynamics of the system. A novel new feature of the code is that the resolution of the model can be significantly increased in selected parts of the domain, which allows for self-consistent modelling of mantle-lithosphere interaction. In the present study this feature is employed to study how crustal scale deformation around the subduction zone is influenced by surface processes and by flow in the upper mantle. Using systematic 2-D numerical simulations, we explore the parameters that are dominant in controlling near- surface structures, both with regards to changes in topography over time, and subsurface features such as Moho undulations. The main parameters that have been varied are: the lithospheric density structure; the strength of the lower crust; the amounts of erosion; imposed pushing versus density-driven (slab-pull and ridge- push) convergence; the upper boundary condition (free surface versus free slip); rheology (non-Newtonian versus Newtonian, viscous, visco-elasto-plastic); and finally the effect of an imposed slab breakoff. In all cases we track surface uplift, subduction evolution and rock exhumation history. The results can be compared to evidence from areas such as Taiwan where continental subduction or convergence is thought to be happening. Preliminary results indicate that a low viscosity lower crust may contribute to crustal uplift.

  5. Tidal controls on riverbed denitrification along a tidal freshwater zone

    Science.gov (United States)

    Knights, Deon; Sawyer, Audrey H.; Barnes, Rebecca T.; Musial, Cole T.; Bray, Samuel

    2017-01-01

    In coastal rivers, tidal pumping enhances the exchange of oxygen-rich river water across the sediment-water interface, controlling nitrogen cycling in riverbed sediment. We developed a one-dimensional, fluid flow and solute transport model that quantifies the influence of tidal pumping on nitrate removal and applied it to the tidal freshwater zone (TFZ) of White Clay Creek (Delaware, USA). In field observations and models, both oxygenated river water and anoxic groundwater deliver nitrate to carbon-rich riverbed sediment. A zone of nitrate removal forms beneath the aerobic interval, which expands and contracts over daily timescales due to tidal pumping. At high tide when oxygen-rich river water infiltrates into the bed, denitrification rates decrease by 25% relative to low tide. In the absence of tidal pumping, our model predicts that the aerobic zone would be thinner, and denitrification rates would increase by 10%. As tidal amplitude increases toward the coast, nitrate removal rates should decrease due to enhanced oxygen exchange across the sediment-water interface, based on sensitivity analysis. Denitrification hot spots in TFZs are more likely to occur in less permeable sediment under lower tidal ranges and higher rates of ambient groundwater discharge. Our models suggest that tidal pumping is not efficient at removing surface water nitrate but can remove up to 81% of nitrate from discharging groundwater in the TFZ of White Clay Creek. Given the high population densities of coastal watersheds, the reactive riverbeds of TFZs play a critical role in mitigating new nitrogen loads to coasts.

  6. Landslide susceptibility mapping in three selected target zones in Afghanistan

    Science.gov (United States)

    Schwanghart, Wolfgang; Seegers, Joe; Zeilinger, Gerold

    2015-04-01

    In May 2014, a large and mobile landslide destroyed the village Ab Barek, a village in Badakshan Province, Afghanistan. The landslide caused several hundred fatalities and once again demonstrated the vulnerability of Afghanistan's population to extreme natural events following more than 30 years of civil war and violent conflict. Increasing the capacity of Afghanistan's population by strengthening the disaster preparedness and management of responsible government authorities and institutions is thus a major component of international cooperation and development strategies. Afghanistan is characterized by high relief and widely varying rock types that largely determine the spatial distribution as well as emplacement modes of mass movements. The major aim of our study is to characterize this variability by conducting a landslide susceptibility analysis in three selected target zones: Greater Kabul Area, Badakhshan Province and Takhar Province. We expand on an existing landslide database by mapping landforms diagnostic for landslides (e.g. head scarps, normal faults and tension cracks), and historical landslide scars and landslide deposits by visual interpretation of high-resolution satellite imagery. We conduct magnitude frequency analysis within subregional physiogeographic classes based on geological maps, climatological and topographic data to identify regional parameters influencing landslide magnitude and frequency. In addition, we prepare a landslide susceptibility map for each area using the Weight-of-Evidence model. Preliminary results show that the three selected target zones vastly differ in modes of landsliding. Low magnitude but frequent rockfall events are a major hazard in the Greater Kabul Area threatening buildings and infrastructure encroaching steep terrain in the city's outskirts. Mass movements in loess covered areas of Badakshan are characterized by medium to large magnitudes. This spatial variability of characteristic landslide magnitudes and

  7. Factors Influencing Examination Malpractice in Secondary Schools ...

    African Journals Online (AJOL)

    The main purpose of this study was to investigate factors influencing examination malpractice in some selected secondary schools in Cross River State, Nigeria. A sample of one thousand two hundred (1200) students were selected across the three educational zones of Ogoja, Ikom and Calabar using stratified, random ...

  8. INFLUENCE OF WEED CONTROL METHODS, POULTRY MANURE ...

    African Journals Online (AJOL)

    User

    INFLUENCE OF WEED CONTROL METHODS, POULTRY MANURE AND PLANTING. PATTERN ON GROWTH AND YIELD ATTRIBUTES OF MAIZE (Zea mays L.) IN THE. NORTHERN GUINEA SAVANNAH ZONE OF NIGERIA. Bature, M.S.,1 Ishaya, D.B.,2 2Mahadi, M.A2, Sharifai, A.I2; Muhammed, A.A2; Hassan, A. H1;.

  9. Integrated seismic interpretation of the Carlsberg Fault zone, Copenhagen, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Lars; Thybo, Hans; Jørgensen, Mette Iwanouw

    2005-01-01

    We locate the concealed Carlsberg Fault zone along a 12-km-long trace in the Copenhagen city centre by seismic refraction, reflection and fan profiling. The Carlsberg Fault is located in a NNW-SSE striking fault system in the border zone between the Danish Basin and the Baltic Shield. Recent...... the fault zone. The fault zone is a shadow zone to shots detonated outside the fault zone. Finite-difference wavefield modelling supports the interpretations of the fan recordings. Our fan recording approach facilitates cost-efficient mapping of fault zones in densely urbanized areas where seismic normal...

  10. Subduction zones seen by GOCE gravity gradients

    DEFF Research Database (Denmark)

    Švarc, Mario; Herceg, Matija; Cammarano, Fabio

    In this study, the GOCE (Gravity field and steady state Ocean Circulation Explorer) gradiometry data were used to study geologic structures and mass variations within the lithosphere in areas of known subduction zones. The advantage of gravity gradiometry over other gravity methods...... is that gradients are extremely sensitive to localized density contrasts within regional geological settings, which makes it ideally suited for detecting subduction zones. Second order gravity gradients of disturbing potential were extracted from global geopotential model, the fifth release GOCE model ‘EGM_TIM_RL05......’. In order to remove the signal which mainly corresponds to the gravity signal of the lower mantle, long wavelength part of the gravity signal was removed up to degree and order 60. Because the areas with notable topography differences coincide with subduction zones, topography correction was also performed...

  11. Thermal impact of magmatism in subduction zones

    Science.gov (United States)

    Rees Jones, David W.; Katz, Richard F.; Tian, Meng; Rudge, John F.

    2018-01-01

    Magmatism in subduction zones builds continental crust and causes most of Earth's subaerial volcanism. The production rate and composition of magmas are controlled by the thermal structure of subduction zones. A range of geochemical and heat flow evidence has recently converged to indicate that subduction zones are hotter at lithospheric depths beneath the arc than predicted by canonical thermomechanical models, which neglect magmatism. We show that this discrepancy can be resolved by consideration of the heat transported by magma. In our one- and two-dimensional numerical models and scaling analysis, magmatic transport of sensible and latent heat locally alters the thermal structure of canonical models by ∼300 K, increasing predicted surface heat flow and mid-lithospheric temperatures to observed values. We find the advection of sensible heat to be larger than the deposition of latent heat. Based on these results we conclude that thermal transport by magma migration affects the chemistry and the location of arc volcanoes.

  12. Magnetic Fields in the Solar Convection Zone

    Directory of Open Access Journals (Sweden)

    Yuhong Fan

    2009-12-01

    Full Text Available Active regions on the solar surface are generally thought to originate from a strong toroidal magnetic field generated by a deep seated solar dynamo mechanism operating at the base of the solar convection zone. Thus the magnetic fields need to traverse the entire convection zone before they reach the photosphere to form the observed solar active regions. Understanding this process of active region flux emergence is therefore a crucial component for the study of the solar cycle dynamo. This article reviews studies with regard to the formation and rise of active region scale magnetic flux tubes in the solar convection zone and their emergence into the solar atmosphere as active regions.

  13. Urban planning as a trading zone

    CERN Document Server

    Mäntysalo, Raine

    2013-01-01

    'Trading zone' is a concept introduced by Peter Galison in his social scientific research on how scientists representing different sub-cultures and paradigms have been able to coordinate their interaction locally. In this book, Italian and Finnish planning researchers extend the use of the concept to different contexts of urban planning and management, where there is a need for new ideas and tools in managing the interaction of different stakeholders. The trading zone concept is approached as a tool in organizing local platforms and support systems for planning participation, knowledge production, decision making and local conflict management. In relation to the former theses of communicative planning theory that stress the ideals of consensus, mutual understanding and universal reason, the 'trading zone approach', outlined in this book, offers a different perspective. It focuses on the potentiality to coordinate locally the interaction of different stakeholders without requiring the deeper sharing of underst...

  14. Multi-zone cooling/warming garment

    Science.gov (United States)

    Koscheyev, Victor S. (Inventor); Leon, Gloria R. (Inventor); Dancisak, Michael J. (Inventor)

    2006-01-01

    A thermodynamically efficient garment for cooling and/or heating a human body. The thermodynamic efficiency is provided in part by targeting the heat exchange capabilities of the garment to specific areas and/or structures of the human body. The heat exchange garment includes heat exchange zones and one or more non-heat exchange zones, where the heat exchange zones are configured to correspond to one or more high density tissue areas of the human body when the garment is worn. A system including the garment can be used to exchange heat with the adjacent HD tissue areas under the control of a feedback control system. Sensed physiological parameters received by the feedback control system can be used to adjust the characteristics of heat exchange fluid moving within the heat exchange garment.

  15. Dead Zone Accretion Flows in Protostellar Disks

    Science.gov (United States)

    Turner, Neal; Sano, T.

    2008-01-01

    Planets form inside protostellar disks in a dead zone where the electrical resistivity of the gas is too high for magnetic forces to drive turbulence. We show that much of the dead zone nevertheless is active and flows toward the star while smooth, large-scale magnetic fields transfer the orbital angular momentum radially outward. Stellar X-ray and radionuclide ionization sustain a weak coupling of the dead zone gas to the magnetic fields, despite the rapid recombination of free charges on dust grains. Net radial magnetic fields are generated in the magnetorotational turbulence in the electrically conducting top and bottom surface layers of the disk, and reach the midplane by ohmic diffusion. A toroidal component to the fields is produced near the midplane by the orbital shear. The process is similar to the magnetization of the solar tachocline. The result is a laminar, magnetically driven accretion flow in the region where the planets form.

  16. Flow and transport in Riparian Zones

    DEFF Research Database (Denmark)

    Jensen, Jannick Kolbjørn

    the capacity of a riparian zone for removing nitrate. In non-flooding periods groundwater flows horizontally and discharges directly to the river. During periods with flooding parts of the groundwater is forced upwards through the peat layer and causes flow in the area beneath the flood to be more stagnant...... scenarios with changing conditions for flow (steady state with no flooding or transient with flooding), hydrogeology, denitrification rate, and extent of flooding it is demonstrated how flow paths, residence times, and nitrate removal are affected. With this previous conceptual models on the hydrology...... of riparian zones are extended by accounting for the effect of flooding and a key result is that flooding enhances nitrate removal given the right hydrogeological characteristics. Moreover the re-established riparian zones were characterized to understand the effects of flooding on subsurface hydrological...

  17. Friction of Shear-Fracture Zones

    Science.gov (United States)

    Riikilä, T. I.; Pylväinen, J. I.; Åström, J.

    2017-12-01

    A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous self-lubrication. A "weak shear zone" is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstrate here that weak shear zones are far more general, and that their emergence only demands that a microscopic, i.e., fragment-scale, stress relaxation mechanism develops during the fracture process.

  18. Unsaturated Zone Flow Model Expert Elicitation Project

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K. J.

    1997-05-30

    This report presents results of the Unsaturated Zone Flow Model Expert Elicitation (UZFMEE) project at Yucca Mountain, Nevada. This project was sponsored by the US Department of Energy (DOE) and managed by Geomatrix Consultants, Inc. (Geomatrix), for TRW Environmental Safety Systems, Inc. The objective of this project was to identify and assess the uncertainties associated with certain key components of the unsaturated zone flow system at Yucca Mountain. This assessment reviewed the data inputs, modeling approaches, and results of the unsaturated zone flow model (termed the ''UZ site-scale model'') being developed by Lawrence Berkeley National Laboratory (LBNL) and the US Geological Survey (USGS). In addition to data input and modeling issues, the assessment focused on percolation flux (volumetric flow rate per unit cross-sectional area) at the potential repository horizon. An understanding of unsaturated zone processes is critical to evaluating the performance of the potential high-level nuclear waste repository at Yucca Mountain. A major goal of the project was to capture the uncertainties involved in assessing the unsaturated flow processes, including uncertainty in both the models used to represent physical controls on unsaturated zone flow and the parameter values used in the models. To ensure that the analysis included a wide range of perspectives, multiple individual judgments were elicited from members of an expert panel. The panel members, who were experts from within and outside the Yucca Mountain project, represented a range of experience and expertise. A deliberate process was followed in facilitating interactions among the experts, in training them to express their uncertainties, and in eliciting their interpretations. The resulting assessments and probability distributions, therefore, provide a reasonable aggregate representation of the knowledge and uncertainties about key issues regarding the unsaturated zone at the Yucca

  19. Magnetic Fields in the Solar Convection Zone

    Directory of Open Access Journals (Sweden)

    Fan Yuhong

    2004-07-01

    Full Text Available Recent studies of the dynamic evolution of magnetic flux tubes in the solar convection zone are reviewed with focus on emerging flux tubes responsible for the formation of solar active regions. The current prevailing picture is that active regions on the solar surface originate from strong toroidal magnetic fields generated by the solar dynamo mechanism at the thin tachocline layer at the base of the solar convection zone. Thus the magnetic fields need to traverse the entire convection zone before they reach the photosphere to form the observed solar active regions. This review discusses results with regard to the following major topics: 1. the equilibrium properties of the toroidal magnetic fields stored in the stable overshoot region at the base of the convection zone, 2. the buoyancy instability associated with the toroidal magnetic fields and the formation of buoyant magnetic flux tubes, 3. the rise of emerging flux loops through the solar convective envelope as modeled by the thin flux tube calculations which infer that the field strength of the toroidal magnetic fields at the base of the solar convection zone is significantly higher than the value in equipartition with convection, 4. the minimum twist needed for maintaining cohesion of the rising flux tubes, 5. the rise of highly twisted kink unstable flux tubes as a possible origin of d -sunspots, 6. the evolution of buoyant magnetic flux tubes in 3D stratified convection, 7. turbulent pumping of magnetic flux by penetrative compressible convection, 8. an alternative mechanism for intensifying toroidal magnetic fields to significantly super-equipartition field strengths by conversion of the potential energy associated with the superadiabatic stratification of the solar convection zone, and finally 9. a brief overview of our current understanding of flux emergence at the surface and post-emergence evolution of the subsurface magnetic fields.

  20. Analysis of the course of rheumatoid arthritis depending on the climatic and geographic zones of Uzbekistan.

    Science.gov (United States)

    Akhmedov, Khalmurad Sadullaevich; Gadaev, Abdigaffar Gadaevich; Sayfiyev, Nodir Yakubovich

    2014-01-01

    The aim of this study was to evaluate the features of rheumatoid arthritis (RA) as well as other health problems and treatment necessities in various climatic and geographic zones of Uzbekistan. The data on 2013 patients with a confirmed diagnosis of RA were collected retrospectively. The results showed that the Khorezm and Surkhandarya regions dominated by indicators of disease activity and severity, such as a more expressed progressive course; in addition, marked alterations in the reproductive system, especially in women, were observed as well. In contrast, patients from the Namangan and Tashkent zones were characterized by relatively better parameters of interest. In conclusion, the differences in climatic and geographic zones in Uzbekistan may be important for patients with RA. More in-depth studies are needed to get a more accurate insight into the possible influence of climate and environmental factors on RA.

  1. Dispersive Behavior of the Mixing Zone between a Shallow Freshwater Lens and Upward Seeping Saline Groundwater

    Science.gov (United States)

    Eeman, S.; Leijnse, A.; van der Zee, S. E. A. T. M.

    2009-04-01

    Introduction Salt water intrusion and upward seepage of salt groundwater is a widespread problem in low-lying areas of coastal zones that are important for agriculture or ecology, such as in the North and West regions of the Netherlands, Southwest Florida, and many other deltaic areas, for example Camargue in France and the Nile delta in Egypt. Where the soil surface is situated below sea level, saline groundwater moves upward into superficial water networks. On the other hand, infiltrating rainwater forms small-scale fresh water lenses. The system is also comparable to the situation that develops when "skimming wells" are used, for example for irrigation in Northern India. The lenses we are studying have a thickness ranging from less then one up to several meters, their width depending on drainage density (generally 20-500 m). Field data show that the transition zone can be as thick as the fresh water lens itself. Therefore a sharp interface model cannot be assumed suitable to analyze such lenses (Sakr, 1999). When comparing numerical and analytical models for steady situations, when flow lines are parallel to the transition zone, we found that the analytical model represents the centre of the transition zone quite accurately. The width can be estimated only roughly. Climate change and human influence, through water level control and/or pumping, cause these lenses to grow or shrink. During this volume change, flow lines have a component perpendicular to the transition zone between fresh and saline water. This increases longitudinal dispersion, and thereby widens the transition zone further. Research This work is a combination of numerical modeling, dimension analysis and fieldwork; we use SUTRA (Voss and Provost, 2003), which is capable of including both density dependence and unsaturated zones. To characterize the shape of the lens and the transition zone we use spatial moments. For 2 sites in the Southwest of the Netherlands we are continuously monitoring

  2. 33 CFR 147.847 - Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone.

    Science.gov (United States)

    2010-07-01

    ... Production, Storage, and Offloading System Safety Zone. 147.847 Section 147.847 Navigation and Navigable... ZONES § 147.847 Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone. (a) Description. The BW PIONEER, a Floating Production, Storage and Offloading (FPSO) system, is in...

  3. Special Economic Zones, 20 years after

    DEFF Research Database (Denmark)

    Jensen, Camilla; Winiarczyk, Marcin

    In this paper the authors undertake an ex-post evaluation of whether the special economic zones (SEZs) introduced in Poland in 1994 have been successful in meeting regional development objectives. They evaluate the policy on as many of its objectives as possible: employment creation, business...... technologies and reduced air pollution, the authors find only a small positively moderating effect of the policy on what are traditionally economically disadvantaged areas in Poland that used to be dependent on the socialist production model. Hence, despite high levels of FDI, the zones policy has not managed...

  4. Global challenges in integrated coastal zone management

    DEFF Research Database (Denmark)

    Growing pressure from increasingly diverse human activities coupled with climate change impacts threaten the functional integrity of coastal ecosystems around the globe. A multi-disciplinary approach towards understanding drivers, pressures and impacts in the coastal zone requires effective....../mitigation to change in coastal systems Coastal governance Linking science and management Comprising a huge wealth of information, this timely and well-edited volume is essential reading for all those involved in coastal zone management around the globe. All libraries in research establishments and universities where...

  5. Primary extranodal marginal zone lymphoma - Epididymis

    Directory of Open Access Journals (Sweden)

    Shanmugasundaram Rajaian

    2011-01-01

    Full Text Available An elderly male presented with painful swelling in the right side of scrotum. He was treated with antibiotics for epididymoorchitis without any response. Ultrasound examination revealed a hypoechoic vascular mass in the tail of the epididymis. Fine needle aspirate cytology was inconclusive. Excision of the mass was done and biopsy revealed primary extranodal marginal zone lymphoma arising from mucosa associated lymphoid tissue (MALT of epididymis. Marginal zone lymphoma arising from the MALT of epididymis is very rare. Lymphoma should be considered as a differential diagnosis of any epididymal swelling unresponsive to conservative treatment. We report a rare case of primary extranodal marginal lymphoma of MALT arising from epididymis.

  6. Application of enthalpy model for floating zone silicon crystal growth

    Science.gov (United States)

    Krauze, A.; Bergfelds, K.; Virbulis, J.

    2017-09-01

    A 2D simplified crystal growth model based on the enthalpy method and coupled with a low-frequency harmonic electromagnetic model is developed to simulate the silicon crystal growth near the external triple point (ETP) and crystal melting on the open melting front of a polycrystalline feed rod in FZ crystal growth systems. Simulations of the crystal growth near the ETP show significant influence of the inhomogeneities of the EM power distribution on the crystal growth rate for a 4 in floating zone (FZ) system. The generated growth rate fluctuations are shown to be larger in the system with higher crystal pull rate. Simulations of crystal melting on the open melting front of the polycrystalline rod show the development of melt-filled grooves at the open melting front surface. The distance between the grooves is shown to grow with the increase of the skin-layer depth in the solid material.

  7. The role of information technology on developing free zone markets

    Directory of Open Access Journals (Sweden)

    Naser Azad

    2012-04-01

    Full Text Available Information technology (IT plays an important role on developing different markets. Today, people can easily purchase goods from different stores using varieties of IT based facilities such as POS, ATM, etc. These devices help customers literally carry significant amount of money without bothering about any possible threat. In this paper, we study the impact of IT on developing businesses located mainly on free zones or in the borders of countries. We have distributed 300 questionnaires consists of 35 questions among different people and build structural equations using 28 variables. The results are analyzed using LISREL software package and they are grouped in five different groups including management, social and cultural, organizational, technical and investment factors. Chi-square represents a relatively high value, which means the null hypothesis can be rejected when All t-student represent meaningful values when the significance level is five percent. The results indicate that all these factors influence IT development, significantly.

  8. Pumping-Test Evaluation of Fault-Zone Hydraulic Properties in a Fractured Sandstone

    Science.gov (United States)

    Johnson, N. M.

    2014-12-01

    Subzones of both reduced and enhanced permeability are often ascribed to fault zones, consistent with a fault-core/damage-zone conceptualization, with associated implications for assessing potential contaminant transport. Within this context, a 31-day pumping test was conducted in relation to a relatively minor, 2000 m long fault zone cutting fractured Cretaceous sandstone interbedded with siltstone and shale at a groundwater remediation site in the Simi Hills of southern California during March-April 2013. Our objective was to evaluate the potential hydrogeologic influence of the fault zone on groundwater movement across and along it by observing the spatial patterns of drawdown and estimated hydraulic properties. A 122 m deep open borehole was pumped at a constant rate of approximately 112 L/min while monitoring hydraulic heads in 14 observation wells, two completed with multi-level systems, within 750 m of the pumping well. Hydraulic heads were monitored for more than 9 months before, during, and after the test. Prior to the test, we used the site's three-dimensional, equivalent-porous-media groundwater flow model to anticipate the potential response of alternative fault-zone permeability structures. The results suggest that the fault zone may be slightly more permeable (by a factor of about 2 or less) and less confined than the fractured sandstone away from the fault, and is not a significant barrier to groundwater flow across it. Within the areal extent of observed drawdown, the site's hydrostratigraphic structures exhibited a relatively greater hydraulic influence. The pattern and magnitude of observed drawdown lie within the range of pre-test model simulations, and the test results are now being used to revise and recalibrate the model.

  9. Influence of seawater and its aerosols on copper patina composition

    Energy Technology Data Exchange (ETDEWEB)

    Veleva, L., E-mail: veleva@mda.cinvestav.mx [Applied Physics Department, Center for Investigation and Advanced Study, CINVESTAV-Merida, Carr. Ant. a Progreso, Km. 6, 97310 Merida (Mexico); Farro, W. [Department of Chemistry, Universidad Nacional de Trujillo, Av. Juan Pablo II s/n, Ciudad Universitaria, Urb. San Andres, Trujillo (Peru)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Copper patina was grown during one-year period on samples exposed to splash, tidal, full immersion sea zone and atmospheric aerosols. Black-Right-Pointing-Pointer The cuprite and atacamite contributed most to patina formation. Black-Right-Pointing-Pointer Atacamite became the sole majority phase in the full immersion zone. Black-Right-Pointing-Pointer Cuprite decreased over time and posnjakite and chalcanthite appeared as minority phases. Black-Right-Pointing-Pointer Copper patina composition is strongly influenced by chloride pollution and specific zone conditions. - Abstract: X-ray diffraction analysis was used to monitor patina composition on copper samples exposed during one-year period to different seawater zones (splash, tidal and full immersion) and marine atmospheric aerosols. Two phases contributed most to patina formation: cuprite (copper oxide) and atacamite (copper chloride compound). Their relative XRD spectra intensities were very similar in patina formed in the tidal sea zone, but atacamite became the sole majority phase in the full immersion zone. The cuprite phase decreased over time, and two minority copper sulfates phases appeared: posnjakite and chalcanthite (CuSO{sub 4}). The results revealed that copper patina composition is strongly influenced by chloride pollution and specific zone conditions. Additional factors, such as wind-blown sand, continuous dredging in coastal areas and vessel docking, influenced degree of pollutant compound adherence to patinas and consequently their structure (porous or compact).

  10. Climate zones on Pluto and Charon

    Science.gov (United States)

    Binzel, Richard P.; Earle, Alissa M.; Buie, Marc W.; Young, Leslie A.; Stern, S. Alan; Olkin, Cathy B.; Ennico, Kimberly; Moore, Jeffrey M.; Grundy, Will; Weaver, Harold A.; Lisse, Carey M.; Lauer, Tod R.; New Horizons Geology; Geophysics Imaging Team

    2017-05-01

    We give an explanatory description of the unusual ;climate zones; on Pluto that arise from its high obliquity (mean 115°) and high amplitude (±12°) of obliquity oscillation over a 2.8 million year period. The zones we describe have astronomically defined boundaries and do not incorporate atmospheric circulation. For such a high mean obliquity, the lines of tropics (greatest latitudes where the Sun can be overhead) cycle closer to each pole than does each arctic circle, which in turn cycle nearly to the equator. As a consequence in an astronomical context, Pluto is more predominantly ;tropical; than ;arctic.; Up to 97% of Pluto's surface area can experience overhead Sun when the obliquity cycle is at its minimum of 103°. At this same obliquity phase (most recently occurring 0.8 Myr ago), 78% of Pluto's surface experienced prolonged intervals without sunlight or ;arctic winter; (and corresponding ;arctic summer;). The intersection of these climate zones implies that a very broad range of Pluto's latitudes (spanning 13-77° in each hemisphere; 75% of the total surface area) are both tropical and arctic. While some possible correlations to these climate zones are suggested by comparison with published maps of Pluto and Charon yielded by the New Horizons mission, in this work we present a non-physical descriptive analysis only. For example, the planet-wide dark equatorial band presented by Stern et al. (2015; Science, 350, 292-299) corresponds to Pluto's permanent ;diurnal zone.; In this zone spanning latitudes within ±13° of the equator, day-night cycles occur each Pluto rotation (6.4 days) such that neither ;arctic winter; nor ;arctic summer; has been experienced in this zone for at least 20 million years. The stability of this and other climate zones may extend over several Gyr. Temperature modeling shows that the continuity of diurnal cycles in this region may be the key factor enabling a long-term stability for the high albedo contrast between Tombaugh Regio

  11. Occurrence and distribution characteristics of fluids in tight sandstone reservoirs in the Shilijiahan zone, northern Ordos Basin

    Directory of Open Access Journals (Sweden)

    Gongqiang Li

    2017-05-01

    Full Text Available High-yield gas layers, low-yield gas layers and (gas bearing water layers of Upper Paleozoic coexist in the Shilijiahan zone in the northern Ordos Basin, but gas–water distribution characteristics, laws and influence factors are not understood well, so the exploration and development of natural gas in this zone are restricted. In this paper, statistical analysis was carried out on the data of Upper Paleozoic formation water in this zone, e.g. salinity, pH value and ion concentration. It is shown that the formation water in this zone is of CaCl2 type. Then, the origin, types, controlling factors and spatial distribution characteristics of formation water were figured out by using core, mud logging, well logging and testing data, combined with the classification and evaluation results of geochemical characteristics of formation water. Besides, the logging identification chart of gas, water and dry layers in this zone was established. Finally, the occurrence and distribution laws of reservoir fluids were defined. The formation water of CaCl2 type indicates a good sealing capacity in this zone, which is favorable for natural gas accumulation. It is indicated that the reservoir fluids in this zone exist in the state of free water, capillary water and irreducible water. Free water is mainly distributed in the west of this zone, irreducible water in the east, and capillary water in the whole zone. The logging identification chart has been applied in many wells in this zone like Well Jin 86. The identification result is basically accordant with the gas testing result. It is verified that gas and water layers can be identified effectively based on this logging identification chart.

  12. Measuring Hydrodynamics and Sediment Transport in the Swash Zone

    Science.gov (United States)

    Puleo, J. A.

    2014-12-01

    The swash zone is the most landward region of the nearshore where wave energy is ultimately dissipated or reflected. It is the most accessible region of the nearshore but is the most challenging for obtaining measurements and performing numerical modeling simulations. The challenging aspects are related to the moving shoreline, rapid changes in water depth, bed level fluctuations, swift, turbulent, direction-reversing flows, large suspended, bed and sheet flow sediment loads, large void fraction, and fluid infiltration and exfiltration from the beach. The major hurdle numerical modelers face is predicting sediment transport rates on a swash-by-swash basis as errors rapidly lead to inaccuracies in simulated morphological evolution. Recent advances in measurement capabilities are now helping to fill gaps in understanding of sediment transport processes and, in turn, improve predictive capability. Newly developed acoustic Doppler profiling velocimeters have allowed for the measurement of hydrodynamics in the direct vicinity of the bed including boundary layer development, bed shear stresses and turbulence dissipation. Bed shear stresses on natural beaches have been estimated at over 20 N/m2; an order of magnitude larger than in the surf zone. Vertical profiles of turbulence dissipation increase near the bed and near the water surface during uprush (shoreward-directed motion) indicating the simultaneous importance of bottom shear and bore-generated turbulence during this phase of motion. Dissipation during backwash (offshore-directed motion) originates at the bed with little influence from fluid motion near the water surface. Other sensors have enabled, for the first time, the measurement of time dependent sheet flow concentrations. Sheet flow thicknesses have been found to exceed 0.03 m under some natural swash zone conditions and concentrations within the mobile sheet flow layer approach the packed bed limit. Sheet flow sediment concentration profiles for varying

  13. Anatomy of an escape tectonic zone: Western Irian Jaya (Indonesia)

    Science.gov (United States)

    Pubellier, Manuel; Ego, Frédéric

    2002-07-01

    The western fold-and-thrust belt of New Guinea in Irian Jaya is presently a complex boundary, dominated by the Bird's Head block escape from the collision between the Australian plate and the remnants of volcanic belts carried by the Pacific plate. The escape rate given by geodetic measurements is of the order of 7 cm/yr, and movement is accommodated by a broad shear zone. We analyze this shear pattern using fault slip analyses performed in the field from 1992 to 1996, combined with focal mechanism inversions, moment tensors summations, and surface trace of structures inferred from radar and multispectral satellite images. Time control of the deformation is attained by isotope dating of the recent syntectonic intrusives. The geometry of the macro and microstructures occurred in two stages from the early Pliocene to the Present. The first stage (5 to 2 Ma) is marked by flat-and-ramps structures guided by N60°E lateral ramps associated with a N60°E cleavage, affecting the whole of western Irian Jaya. The second stage (2 Ma to Present) shows the collapse of the western fold-and-thrust belt and the escape of the Bird's Head and the Lengguru belts along N60°E transtensile faults. In the latter stage, the strike-slip offset is distributed on the N60°E schistosity zone along which some fracture planes are reactivated as left-lateral transtensile faults. Shallow earthquakes moment tensors have been inverted for stress and summed to get strain rates to define contrasting structural provinces. The spatial variations in both stress and strain fields from earthquakes and microtectonics show that (1) they are consistent and are assumed to be coeval, (2) they reveal that oblique convergence is partitioned, and (3) they are influenced by the existence of a free boundary. We see no significant rotation of stress axes laterally along the escape zone. Instead, stresses change according to the different orientations of basement structures and thus undergo rapid spatial variations

  14. The yellow zone in asthma treatment: is it a gray zone?

    Science.gov (United States)

    Dinakar, Chitra; Reddy, Mamta

    2004-01-01

    To review the available literature on methods of preventing and minimizing exacerbations and to target problems for improvement. PubMed and Cochrane Review searches of the English-language literature using the following key yellow zone terms: asthma exacerbation, self-management plans, inhaled corticosteroids, and acute management of asthma exacerbations. Articles relevant to our yellow zone intervention inquiry. The National Institutes of Health (NIH) guidelines advocate that physicians give patients written action plans with instructions on managing home (yellow zone) exacerbations. However, the criteria used to identify the yellow zone are ambiguous and often confusing to patients and physicians. In addition, apart from a passing mention that doubling doses of inhaled corticosteroids may be an option in asthma step-up care, the guidelines contain no recommendations for yellow zone treatment strategies. This deficiency is directly related to the paucity of organized evidence on the efficacy of the various pharmacological interventions that can be used during an exacerbation. Translating the NIH guidelines into realistic clinical practice requires a clearer and more patient-friendly definition of the yellow zone, and this improved definition will facilitate the prescription of effective interventions in the management of yellow zone exacerbations.

  15. Subduction of oceanic plate irregularities and seismicity distribution along the Mexican Subduction Zone

    Science.gov (United States)

    Manea, Marina; Constantin Manea, Vlad; Gerya, Taras; Wong, Raul-Valenzuela; Radulian, Mircea

    2017-04-01

    It is known that oceanic plates morphology is not a simple one, but rather complicated by a series of irregularities as seamounts, fracture zones and mid-ocean ridges. These features present on the oceanic floor form part of the fabric of oceanic crust, and once formed they move together with the oceanic plates until eventually enter a subduction zone. Offshore Mexico the oceanic Cocos plate seafloor is littered with relatively small but numerous seamounts and seamount chains, and also large fracture zones. In this study we investigate the relationship between these oceanic irregularities located in the vicinity of the trench in Mexico and the distribution of subduction seismicity, including the rupture history of large subduction zone earthquakes. Since the interseismic locking degree is influenced by the rheological properties of crustal and mantle rocks, any variations along strike will result in significant changes in seismic behavior due to a change in frictional stability. Our preliminary study shows a direct relationship between the presence of seamounts chains on the incoming oceanic plate and the subduction seismicity distribution. We also found a clear relationship between the subduction of the Tehuantepec fracture zone (TFZ) and the low seismic activity in the region where this fracture zone intersects the trench. This region is also long term conspicuously quiet and considered a seismic gap where no significant large earthquake has occurred in more than 100 years. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations specifically tailored for the subduction of the Cocos plate in the region of TFZ we show that the weakened serpentinized fracture zone is partially scraped out in the forearc region because of its low strength and positive buoyancy. The presence of serpentinite in the fore arc apparently lowers the degree of interseismic locking, producing a seismic gap in southern Mexico.

  16. Focused groundwater controlled feedbacks into the hyporheic zone during baseflow recession.

    Science.gov (United States)

    Malzone, Jonathan M; Lowry, Christopher S

    2015-01-01

    Groundwater surface water interaction in the hyporheic zone remains an important challenge for water resources management and ecosystem restoration. In heterogeneous stratified glacial sediments, reach-scale environments contain an uneven distribution of focused groundwater flow occurring simultaneously with diffusely discharging groundwater. This results in a variation of stream-aquifer interactions, where focused flow systems are able to temporally dominate exchange processes. The research presented here investigates the direct and indirect influences focused groundwater discharge exerts on the hyporheic zone during baseflow recession. Field results demonstrate that as diffuse sources of groundwater deplete during baseflow recession, focused groundwater discharge remains constant. During baseflow recession the hyporheic zone is unable to expand, while the high nitrate concentration from focused discharge changes the chemistry of the stream. The final result is a higher concentration of nitrate in the hyporheic zone as this altered surface water infiltrates into the subsurface. This indirect coupling of focused groundwater discharge and the hyporheic zone is unaccounted for in hyporheic studies at this time. Results indicate important implications for the potential reduction of agricultural degradation of water quality. © 2014, National Ground Water Association.

  17. Identification of dominating factors affecting vadose zone vulnerability by a simulation method

    Science.gov (United States)

    Li, Juan; Xi, Beidou; Cai, Wutian; Yang, Yang; Jia, Yongfeng; Li, Xiang; Lv, Yonggao; Lv, Ningqing; Huan, Huan; Yang, Jinjin

    2017-01-01

    The characteristics of vadose zone vulnerability dominating factors (VDFs) are closely related to the migration and transformation mechanisms of contaminants in the vadose zone, which directly affect the state of the contaminants percolating to the groundwater. This study analyzes the hydrogeological profile of the pore water regions in the vadose zone, and conceptualizes the vadose zone as single lithologic, double lithologic, or multi lithologic. To accurately determine how the location of the pollution source influences the groundwater, we classify the permeabilities (thicknesses) of different media into clay-layer and non-clay-layer permeabilities (thicknesses), and introduce the maximum pollution thickness. Meanwhile, the physicochemical reactions of the contaminants in the vadose zone are represented by the soil adsorption and soil degradability. The VDFs are determined from the factors and parameters in groundwater vulnerability assessment. The VDFs are identified and sequenced in simulations and a sensitivity analysis. When applied to three polluted sites in China, the method improved the weighting of factors in groundwater vulnerability assessment, and increased the reliability of predicting groundwater vulnerability to contaminants. PMID:28387232

  18. Identification of dominating factors affecting vadose zone vulnerability by a simulation method

    Science.gov (United States)

    Li, Juan; Xi, Beidou; Cai, Wutian; Yang, Yang; Jia, Yongfeng; Li, Xiang; Lv, Yonggao; Lv, Ningqing; Huan, Huan; Yang, Jinjin

    2017-04-01

    The characteristics of vadose zone vulnerability dominating factors (VDFs) are closely related to the migration and transformation mechanisms of contaminants in the vadose zone, which directly affect the state of the contaminants percolating to the groundwater. This study analyzes the hydrogeological profile of the pore water regions in the vadose zone, and conceptualizes the vadose zone as single lithologic, double lithologic, or multi lithologic. To accurately determine how the location of the pollution source influences the groundwater, we classify the permeabilities (thicknesses) of different media into clay-layer and non-clay-layer permeabilities (thicknesses), and introduce the maximum pollution thickness. Meanwhile, the physicochemical reactions of the contaminants in the vadose zone are represented by the soil adsorption and soil degradability. The VDFs are determined from the factors and parameters in groundwater vulnerability assessment. The VDFs are identified and sequenced in simulations and a sensitivity analysis. When applied to three polluted sites in China, the method improved the weighting of factors in groundwater vulnerability assessment, and increased the reliability of predicting groundwater vulnerability to contaminants.

  19. Optimization for energy efficiency of underground building envelope thermal performance in different climate zones of China

    Science.gov (United States)

    Shi, Luyang; Liu, Jing; Zhang, Huibo

    2017-11-01

    The object of this article is to investigate the influence of thermal performance of envelopes in shallow-buried buildings on energy consumption for different climate zones of China. For the purpose of this study, an effective building energy simulation tool (DeST) developed by Tsinghua University was chosen to model the heat transfer in underground buildings. Based on the simulative results, energy consumption for heating and cooling for the whole year was obtained. The results showed that the relationship between energy consumption and U-value of envelopes for underground buildings is different compared with above-ground buildings: improving thermal performance of exterior walls cannot reduce energy consumption, on the contrary, may result in more energy cost. Besides, it is can be derived that optimized U-values of underground building envelopes vary with climate zones of China in this study. For severe cold climate zone, the optimized U-value of underground building envelopes is 0.8W/(m2·K); for cold climate zone, the optimized U-value is 1.5W/(m2·K); for warm climate zone, the U-value is 2.0W/(m2·K).

  20. Assessing controls on perched saturated zones beneath the Idaho Nuclear Technology and Engineering Center, Idaho

    Science.gov (United States)

    Mirus, Benjamin B.; Perkins, Kim S.; Nimmo, John R.

    2011-01-01

    Waste byproducts associated with operations at the Idaho Nuclear Technology and Engineering Center (INTEC) have the potential to contaminate the eastern Snake River Plain (ESRP) aquifer. Recharge to the ESRP aquifer is controlled largely by the alternating stratigraphy of fractured volcanic rocks and sedimentary interbeds within the overlying vadose zone and by the availability of water at the surface. Beneath the INTEC facilities, localized zones of saturation perched on the sedimentary interbeds are of particular concern because they may facilitate accelerated transport of contaminants. The sources and timing of natural and anthropogenic recharge to the perched zones are poorly understood. Simple approaches for quantitative characterization of this complex, variably saturated flow system are needed to assess potential scenarios for contaminant transport under alternative remediation strategies. During 2009-2011, the U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, employed data analysis and numerical simulations with a recently developed model of preferential flow to evaluate the sources and quantity of recharge to the perched zones. Piezometer, tensiometer, temperature, precipitation, and stream-discharge data were analyzed, with particular focus on the possibility of contributions to the perched zones from snowmelt and flow in the neighboring Big Lost River (BLR). Analysis of the timing and magnitude of subsurface dynamics indicate that streamflow provides local recharge to the shallow, intermediate, and deep perched saturated zones within 150 m of the BLR; at greater distances from the BLR the influence of streamflow on recharge is unclear. Perched water-level dynamics in most wells analyzed are consistent with findings from previous geochemical analyses, which suggest that a combination of annual snowmelt and anthropogenic sources (for example, leaky pipes and drainage ditches) contribute to recharge of shallow and