WorldWideScience

Sample records for causeways

  1. Modeling the effect of Causeways on Circulation in the Banana River

    Science.gov (United States)

    Saberi, A.; Weaver, R. J.

    2015-12-01

    The Indian River Lagoon (IRL) is a restricted estuary along the east coast of Florida. Although Banana River, a 50 km long sub-basin of IRL, has an outlet to the ocean through the Port Canaveral locks, the locks remain closed when there is no passing vessel. The lack of direct ocean connection results in limited circulation, long flushing time and poor water quality. Existence of the causeways limits the circulation even more. In this study, the impact of the causeways on flushing time is studied. This study also examines the extent to which constructing a low crested weir adjacent to Port Canaveral can improve flushing in this region. ADCIRC 2DDI is forced with meteorological inputs as well as tides to simulate the hydrodynamic properties of the study area and determine the 2D depth-averaged velocity field for four separate cases: Existing System with and without consideration of the causeways, and modified system (adding a weir near port Canaveral) with and without consideration of the causeways. Passive particles are placed in Banana River, and their movement is tracked using a Lagrangian Particle Tracking Model (LPTM). Transport timescales are then computed, and residence time contours as well as pathlines of selected particles are plotted. Results indicate that the narrow raised pathway section of the causeways acts as a plate which diverts the flow direction and generates eddies in the downstream which causes the particles in the vicinity of the causeways remain in the domain for a longer duration. There is a longer residence time for the case in which the causeways are considered. The results with the added weir suggest a noticeable improvement in flushing time and residence time even for the case in which the causeways are considered in the model.

  2. Construction of a Causeway Bridge across the Lake Urmia and its Influence on Drying Trend of the Lake

    Science.gov (United States)

    Ghadimi, M.; Nezammahalleh, M. A.

    2015-12-01

    Construction of a causeway bridge on the Lake Urmia accelerated the drying trend of the largest hyper-saline lake of the world. The objective of the research is to investigate the differences of precipitation and river discharge before and after initiation of the construction of the bridge in 2000. The study area was the watershed of the lake. The averages of the precipitation data in the two periods before and after the project have been interpolated by IDW based on GIS Geostatistical Analyst. The two interpolated precipitation layers were used to be plugged into Student T-test equation in GIS in a spatial basis. To do this, the study area was divided to 25 regions based on drainage sub-basins. Less than 30 sample areas were randomly selected as cases from each of the regions to put into the equation. The discharge data were also compared for the two periods. The results indicated that except in some limited areas, the precipitation differences in the two periods are significant. This means that there were little changes in precipitation and river discharge in the area and consequently the drying may be caused mainly by hydrodynamic changes in the lake due to construction of the causeway. However, it can be argued that the changes in the lake's surface area are accompanied by changes in precipitation and river discharge. The t test statistic can be applied samples based on spatial analysis.

  3. Slope Failure Hazards at Basalt Geomorphosites: A Comparative Analysis of the Giant's Causeway World Heritage Site, UK and Penghu Marine Geopark, Taiwan.

    Science.gov (United States)

    Gruendemann, Ciaran; Chung Lin, Jiun; Smith, Bernard

    2010-05-01

    Columnar basalt landscapes hold a fascination that transcends geographical and cultural boundaries. It is because of this that they feature so prominently on the global register of significant geomorphosites. Arguably the most iconic of these basalt landscapes is the Giant's Causeway in Northern Ireland, a status recognized by its inscription as a World Heritage Site. Recognition at this level invariably brings visitor pressure, and with it concern as to the impact they exert on site integrity. Rarely, however, is the same overt concern expressed for the risks that such sites pose to the visitors - or not at least until disaster strikes. Yet, the very features that make these sites attractive - tall, exposed, largely unconstrained columns - render many of them intrinsically unstable, prone to catastrophic collapse and potentially hazardous to visitors. In this presentation we highlight the nature of these slope instability issues through a comparative analysis of two geographically contrasting basalt geomorphosites. Investigations of slope hazard at the Giant's Causeway have shown that many are linked to the distinctive structural characteristics and weathering patterns of flood basalts. Typically, individual flows comprise a columnar ‘colonnade', topped by a blocky ‘entablature' and separated from the flows above and below it by a structurally weaker, but often less-permeable, palaeosol that formed during periods of volcanic quiescence. The collapse of columns is often facilitated by a combination of weathering along ever-widening joints and wedging outwards by debris that falls into them. This gradual distortion of the colonnade makes columns increasingly susceptible to collapse. Often this is triggered by intense rainfall (perhaps following a dry spell) that rapidly infiltrates joints and is ponded on the underlying palaeosol. The precise nature of the failure (toppling or outwards rotation of the column base) is largely dictated by the nature of the

  4. Costs of berm and causeway alternatives

    International Nuclear Information System (INIS)

    Experiments initiated in February 1985 and still in progress have demonstrated that removal of 30 cm of topsoil brings the specific activity of Bikini Island soil down to the level of that on Eneu and reduces the external exposure rate to gamma rays from an average of 68 pr/h to 5 pr/h. The analytical data completed thus far for food crops grown in the experimental and control areas indicate a parallel response. During 1986 results became available showing that removal of topsoil would also limit productivity. However, it is now known that with adequate care the excavated plot can be as productive as the unexcavated (natural) one. The removal of 30 cm (1 foot) of topsoil at Bikini Island would produce large amounts of waste vegetable matter and approximately 719,000 cubic meters of contaminated topsoil. Three principal alternatives have been considered for the disposal of the spoil. The cost estimates for these and other rehabilitation alternatives were developed in detail by a panel of engineers, chaired by BARC member Arthur S. Kubo, which met in January 1986. The panel's report constitutes Appendix C of BARC Report No. 4

  5. Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.; Ong, H.Y.; Kok, P.W. [and others

    1996-12-31

    The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

  6. 30 CFR 903.700 - Arizona Federal program.

    Science.gov (United States)

    2010-07-01

    ... operations in Arizona conducted on non-Federal and non-Indian lands. To the extent required by 30 CFR part... bridge, dam, dike or causeway may not be constructed over or in a navigable river or other navigable... prevention and control is a misdemeanor. (5) Roads leading into waste dump areas and tailing areas...

  7. 75 FR 81561 - Huron-Manistee National Forests, Michigan, Land and Resource Management Plan Supplemental...

    Science.gov (United States)

    2010-12-28

    ... and the settings needed to provide quality recreational opportunities. DATES: Comments concerning the...--Mio Ranger Station, 107 McKinley Road, Mio, MI, from 4-7 p.m.; 2/02/11--Causeway Bay Hotel (Will be... Forest Service Huron-Manistee National Forests, Michigan, Land and Resource Management Plan...

  8. Gender issues in sport and exercise

    OpenAIRE

    Macfarlane, Duncan J

    1996-01-01

    Proceedings of the Gender Issues in Sport and Exercise Conference organised by the Centre for Physical Education and Sport, the Physical Education and Sports Science Unit of the University of Hong Kong, and sponsored by the Hong Kong Sports Development Board, Saturday, 25 November 1995, Sports House, Causeway Bay, Hong Kong.

  9. Roberts Bank: Ecological crucible of the Fraser River estuary

    Science.gov (United States)

    Sutherland, Terri F.; Elner, Robert W.; O'Neill, Jennifer D.

    2013-08-01

    Roberts Bank, part of the Fraser River delta system on Canada's Pacific coast, is a dynamic estuarine environment supporting important fisheries as well as internationally significant populations of migratory shorebirds. The 8000 ha bank environment comprises a complex of riparian boundaries, intertidal marshes, mud and sand flats, eelgrass meadows, macroalgae and biofilms. Anthropogenic developments (a ferry causeway in 1961 and a port causeway in 1969) have been responsible for changes in tidal flow patterns, tidal elevation, sediment transport and the net expansion of eelgrass beds. The goals of the present study were to (1) directly compare geotechnical properties spanning each side of the coalport causeway, and (2) enhance our understanding of the intercauseway ecosystem under a high-resolution sampling design. Sediment properties (grain size, porosity, organic content, and chlorophyll) and biological communities (eelgrass, macrofauna (0.5-1.0 mm) and meiofauna (0.063-0.5 mm)) were surveyed in 1997 at three stations outside the intercauseway area and three lateral transects spanning the intercauseway tidal flat at tidal heights representing three different habitats: biofilm, Zostera japonica, and Zostera marina. A fine-silt organic-rich porous deposit was observed on the shoreward north side of the coalport causeway relative to the south counterpart, suggesting that consolidation and erosion processes could likely not keep pace with the deposition of Fraser River silt. High chlorophyll levels were found in the protected shoreward northern border of the ferry causeway where fine sands dominate and higher water transparency exists, owing to the redirection of the silt-laden river plume by the coalport causeway. Principle Components Analysis revealed a positive relationship between these porous, organic-rich sediments and cumacean abundance in all regions where eelgrass was absent, including the north side of the coalport causeway. Further, a positive

  10. Density-stratified flow events in Great Salt Lake, Utah, USA: implications for mercury and salinity cycling

    Science.gov (United States)

    Naftz, David L.; Carling, Gregory T.; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Pazmiño, Eddy

    2014-01-01

    Density stratification in saline and hypersaline water bodies from throughout the world can have large impacts on the internal cycling and loading of salinity, nutrients, and trace elements. High temporal resolution hydroacoustic and physical/chemical data were collected at two sites in Great Salt Lake (GSL), a saline lake in the western USA, to understand how density stratification may influence salinity and mercury (Hg) distributions. The first study site was in a causeway breach where saline water from GSL exchanges with less saline water from a flow restricted bay. Near-surface-specific conductance values measured in water at the breach displayed a good relationship with both flow and wind direction. No diurnal variations in the concentration of dissolved (total and MeHg loadings was observed during periods of elevated salinity. The second study site was located on the bottom of GSL where movement of a high-salinity water layer, referred to as the deep brine layer (DBL), is restricted to a naturally occurring 1.5-km-wide “spillway” structure. During selected time periods in April/May, 2012, wind-induced flow reversals in a railroad causeway breach, separating Gunnison and Gilbert Bays, were coupled with high-velocity flow pulses (up to 55 cm/s) in the DBL at the spillway site. These flow pulses were likely driven by a pressure response of highly saline water from Gunnison Bay flowing into the north basin of Gilbert Bay. Short-term flow reversal events measured at the railroad causeway breach have the ability to move measurable amounts of salt and Hg from Gunnison Bay into the DBL. Future disturbance to the steady state conditions currently imposed by the railroad causeway infrastructure could result in changes to the existing chemical balance between Gunnison and Gilbert Bays. Monitoring instruments were installed at six additional sites in the DBL during October 2012 to assess impacts from any future modifications to the railroad causeway.

  11. Holocene morphogenesis of Alexander the Great's isthmus at Tyre in Lebanon

    OpenAIRE

    Marriner, Nick; Morhange, Christophe; Meulé, Samuel

    2007-01-01

    In 332 B.C., Alexander the Great constructed an ≈1,000-m-long causeway to seize the offshore island of Tyre. The logistics behind this engineering feat have long troubled archaeologists. Using the Holocene sedimentary record, we demonstrate that Alexander's engineers cleverly exploited a shallow proto-tombolo, or sublittoral sand spit, to breach the offshore city's defensive impregnability. We elucidate a three-phase geomorphological model for the spit's evolution. Settled since the Bronze Ag...

  12. Tidal dynamics in a frictionally dominated tropical lagoon

    Science.gov (United States)

    Tenorio-Fernandez, L.; Gomez-Valdes, J.; Marino-Tapia, I.; Enriquez, C.; Valle-Levinson, A.; Parra, S. M.

    2016-02-01

    This study examined the dynamics of tidal propagation inside a tropical lagoon. Sea surface elevation (inside) and current profiles (at the inlet) were examined over 60 days at the Chelem lagoon, which is a branched tropical lagoon located in the northern Yucatan Peninsula. Tides were predominantly diurnal with a wavelength at least 20 times longer than the total length of the basin. Spatial variations of sea surface elevation and the longitudinal transport were described in each branch by applying a linear analytical model and the results were compared to observations. Results showed that the coastal lagoon was highly frictional. The tidal signal was attenuated between 30% and 40% toward the lagoon heads, a result of the balance between pressure gradient and frictional forces. A causeway that chokes the western side of the lagoon allowed the propagation of the diurnal signal toward the west head of the basin but damped the semidiurnal signal. The causeway acted as a hydraulic low-pass filter, as in natural choked systems. The causeway's filter effect was included in the analytical model by optimizing the frictional parameters.

  13. Non-proportional bioaccumulation of trace metals and metalloids in the planktonic food web of two Singapore coastal marine inlets with contrasting water residence times.

    Science.gov (United States)

    Calbet, Albert; Schmoker, Claire; Russo, Francesca; Trottet, Aurore; Mahjoub, Mohamed-Sofiane; Larsen, Ole; Tong, Hor Yee; Drillet, Guillaume

    2016-08-01

    We analyzed the concentrations of trace metals/metalloids (TMs) in the water, sediment and plankton of two semi-enclosed marine coastal inlets located north of Jurong Island and separated by a causeway (SW Singapore; May 2012-April 2013). The west side of the causeway (west station) has residence times of approximately one year, and the east side of the causeway (east station) has residence times of one month. The concentrations of most of the TMs in water and sediment were higher in the west than in the east station. In the water column, most of the TMs were homogeneously distributed or had higher concentrations at the surface. Preliminary evidence suggests that the TMs are primarily derived from aerosol depositions from oil combustion and industry. Analyses of TMs in seston (>0.7μm; mostly phytoplankton) and zooplankton (>100μm) revealed that the seston from the west station had higher concentrations of most TMs; however, the concentrations of TMs in zooplankton were similar at the two stations. Despite the high levels of TMs in water, sediment and seston, the bioaccumulation detected in zooplankton was moderate, suggesting either the presence of effective detoxification mechanisms or/and the inefficient transfer of TMs from primary producers to higher trophic levels as a result of the complexity of marine planktonic food webs. In summary, the TM concentrations in water and seston are not reliable indicators of the bioaccumulation at higher trophic levels of the food web. PMID:27104581

  14. Aspects of the biology of Salicornia bigelovii torr. In relation to a proposed restoration of a wind-tidal flat system on the South Texas, USA Coast

    Science.gov (United States)

    Onuf, C.P.

    2006-01-01

    Wind-tidal flats are the dominant coastal wetland type in southern Texas USA. Succulent vascular plants are colonizing the flats in some locations, often where past dredge disposal along navigation channels and other activities have interrupted natural water communication between hypersaline bays and large areas of wind-tidal flats. The objective of this study was to test the feasibility of proposed removal of a causeway at Laguna Atascosa National Wildlife Refuge to restore the historic hydrologic regime and eradicate encroaching vascular plants, mostly Salicornia bigelovii, on the assumption that high sediment salt excluded these vascular plants under natural conditions. Assessment in spring 1998 of the density of Salicornia in relation to elevation and sediment salt of bare and vegetated zones on the vegetated flats on one side of the causeway and entirely barren flats with unimpaired connection to Laguna Madre on the other side of the causeway suggested that sediment salt >0.1 g ml-1 excluded vascular plants. However, bimonthly sampling in 1999-2000 revealed that sediment salt concentrations were >0.1 g ml-1 throughout the vegetated zone in July and more locally in the period of winter low water, with little impairment to established plants. This indicates that if control is desired, it must be exerted at germination and early establishment during and after fall high water. Continuous monitoring of water levels on either side of the causeway suggests that, even with removal of the causeway, flooding with hypersaline lagoon water will be too infrequent to counteract the freshening effect of a permanent hydraulic connection to the main agricultural drain of the lower Rio Grande Valley that has developed at the other end of the salt flat. Monitoring Salicornia distribution over six years documented huge variation between years but no trend toward increasing dominance of the flats. The results of this study illustrate that the most obvious alterations to a site may

  15. Przemiany stosunków wodnych w dolinie górnej Noteci do połowy XIX wieku związane z antropopresją

    OpenAIRE

    Kaniecki, Alfred

    2011-01-01

    The start of the great drainage work in the Upper Noteć valley is connected with the construction of the Bydgoszcz Canal in the years 1772–1774. Earlier, the economic ventures, like building of water mills or causeways, affected the area water conditions only locally. A reconstruction of the initial look of the valley still rests on historical source materials because no research has been conducted in the region to date. Here, we made use of the information from the 15th-century chronicle by ...

  16. Architecture, cobbled roads and chronology of the main sector of the site Las Mercedes-1, Central Caribbean of Costa Rica

    International Nuclear Information System (INIS)

    Results from test-pit excavations, survey, and mapping at Las Mercedes-1, plus the center of a paramount chiefly polity in the Central Caribbean region of Costa Rica, are presented. Information on architecture, construction system, ceramic chronology, and funerary features, are reported. Radiocarbon dates have suggested that important construction works at the site's center were carried out circa A.D. 1000. Two cobble-paved, causeways, perpendicular to the river drainage system, were found to be linked to the main monumental compound as roads for formal access. Interest in the site has been revived and points the way to further researches at the site and its regional sphere. (author)

  17. Comparative Analysis of Pollution in Farmington Bay and the Great Salt Lake, Utah

    OpenAIRE

    Wurtsbaugh, Wayne A.; Marcarelli, Amy; Christison, Cameron; Moore, Joel; Gross, Donovan; Bates, Sophia; Kircher, Sara

    2002-01-01

    Farmington Bay covers 94 mi2 (260 km2) in the SW comer of the Great Salt Lake, and is essentially a separate lake because it is enclosed by Antelope Island and a causeway leading to the island from the mainland. The bay has received wastes from the adjoining Salt Lake City metropolitan area for decades. Because of water quality concerns for Farmington 8ay, the Aquatic Ecology Laboratory class at Utah State University studied the bay and a nearby control site (Bridger Bay) in the Great Salt La...

  18. Effects of eutrophication on the planktonic food web dynamics of marine coastal ecosystems: The case study of two tropical inlets.

    Science.gov (United States)

    Schmoker, Claire; Russo, Francesca; Drillet, Guillaume; Trottet, Aurore; Mahjoub, Mohamed-Sofiane; Hsiao, Shih-Hui; Larsen, Ole; Tun, Karenne; Calbet, Albert

    2016-08-01

    We studied the plankton dynamics of two semi-enclosed marine coastal inlets of the north of Jurong Island separated by a causeway (SW Singapore; May 2012-April 2013). The west side of the causeway (west station) has residence times of ca. one year and is markedly eutrophic. The east side (east station) has residence times of one month and presents lower nutrient concentrations throughout the year. The higher nutrient concentrations at the west station did not translate into significantly higher concentrations of chlorophyll a, with the exception of some peaks at the end of the South West Monsoon. Microzooplankton were more abundant at the west station. The west station exhibited more variable abundances of copepods during the year than did the east station, which showed a more stable pattern and higher diversity. Despite the higher nutrient concentrations at the west station (never limiting phytoplankton growth), the instantaneous phytoplankton growth rates there were generally lower than at the east station. The phytoplankton communities at the west station were top-down controlled, largely by microzooplankton grazing, whereas those of the east station alternated between top-down and bottom-up control, with mesozooplankton being the major grazers. Overall, the trophic transfer efficiency from nutrients to mesozooplankton in the eutrophic west station was less efficient than in the east station, but this was mostly because a poor use of inorganic nutrients by phytoplankton rather than an inefficient trophic transfer of carbon. Some hypotheses explaining this result are discussed. PMID:27326462

  19. Holocene morphogenesis of Alexander the Great's isthmus at Tyre in Lebanon

    Science.gov (United States)

    Marriner, Nick; Morhange, Christophe; Meulé, Samuel

    2007-05-01

    In 332 B.C., Alexander the Great constructed an ≈1,000-m-long causeway to seize the offshore island of Tyre. The logistics behind this engineering feat have long troubled archaeologists. Using the Holocene sedimentary record, we demonstrate that Alexander's engineers cleverly exploited a shallow proto-tombolo, or sublittoral sand spit, to breach the offshore city's defensive impregnability. We elucidate a three-phase geomorphological model for the spit's evolution. Settled since the Bronze Age, the area's geological record manifests a long history of natural and anthropogenic forcings. (i) Leeward of the island breakwater, the maximum flooding surface (e.g., drowning of the subaerial land surfaces by seawater) is dated ≈8000 B.P. Fine-grained sediments and brackish and marine-lagoonal faunas translate shallow, low-energy water bodies at this time. Shelter was afforded by Tyre's elongated sandstone reefs, which acted as a 6-km natural breakwater. (ii) By 6000 B.P., sea-level rise had reduced the dimensions of the island from 6 to 4 km. The leeward wave shadow generated by this island, allied with high sediment supply after 3000 B.P., culminated in a natural wave-dominated proto-tombolo within 1-2 m of mean sea level by the time of Alexander the Great (4th century B.C.). (iii) After 332 B.C., construction of Alexander's causeway entrained a complete anthropogenic metamorphosis of the Tyrian coastal system.

  20. Three dimensional model evaluation of physical alterations of the Caloosahatchee River and Estuary: Impact on salt transport

    Science.gov (United States)

    Sun, Detong; Wan, Yongshan; Qiu, Chelsea

    2016-05-01

    Numerical hydrodynamic modeling provides quantitative understanding of how physical alterations of an estuary may alter the waterbody hydrodynamics and the rate of mixing with the ocean. In this study, a three dimensional hydrodynamic model (CH3D) was used to compare simulated salinities between the existing condition and five historical cases representing varying physical alterations of the Caloosahatchee Estuary involving (1) removal of the headwater structure (S-79); (2) removal of the downstream causeway to Sanibel Island; (3) backfilling an oyster bar near the estuary month; (4) refilling the navigation channel; and (5) the pre-development bathymetric condition. The results suggested that some alterations including the Sanibel Causeway, backfilling the oyster bar and the S-79 structure may have some local effects but did not change estuarine salinity structure significantly. Refilling the navigation channel had a more profound effect, resulting in a dry season salinity reduction of about 5 when compared with the existing condition. The reduced salt transport was more pronounced with the pre-development bathymetry because the estuary as a whole was much shallower than today. The significant system-wide increase in salt transport caused by the historic dredging of the navigation channel in the Caloosahatchee Estuary has significant implications in the development of attainable environmental flow targets for protecting the estuarine ecosystem.

  1. Risk factors and spatial distribution of Schistosoma mansoni infection among primary school children in Mbita District, Western Kenya.

    Directory of Open Access Journals (Sweden)

    Sachiyo Nagi

    2014-07-01

    Full Text Available An increasing risk of Schistosoma mansoni infection has been observed around Lake Victoria, western Kenya since the 1970s. Understanding local transmission dynamics of schistosomiasis is crucial in curtailing increased risk of infection.We carried out a cross sectional study on a population of 310 children from eight primary schools. Overall, a total of 238 (76.8% children were infected with S. mansoni, while seven (2.3% had S. haematobium. The prevalence of hookworm, Trichuris trichiura and Ascaris lumbricoides were 6.1%, 5.2% and 2.3%, respectively. Plasmodium falciparum was the only malaria parasite detected (12.0%. High local population density within a 1 km radius around houses was identified as a major independent risk factor of S. mansoni infection. A spatial cluster of high infection risk was detected around the Mbita causeway following adjustment for population density and other potential risk factors.Population density was shown to be a major factor fuelling schistosome infection while individual socio-economic factors appeared not to affect the infection risk. The high-risk cluster around the Mbita causeway may be explained by the construction of an artificial pathway that may cause increased numbers of S. mansoni host snails through obstruction of the waterway. This construction may have, therefore, a significant negative impact on the health of the local population, especially school-aged children who frequently come in contact with lake water.

  2. Hydrogeochemistry of seasonal variation of Urmia Salt Lake, Iran.

    Science.gov (United States)

    Alipour, Samad

    2006-01-01

    Urmia Lake has been designated as an international park by the United Nations. The lake occupies a 5700 km2 depression in northwestern Iran. Thirteen permanent rivers flow into the lake. Water level in the lake has been decreased 3.5 m in the last decade due to a shortage of precipitation and progressively dry climate. Geologically the lake basin is considered to be a graben of tectonic origin. Na, K, Ca, Li and Mg are the main cations with Cl, SO4, and HCO3 as the main anions. F & Br are the other main elements in the lake. A causeway crossing the lake is under construction, which may affect the lake's annual geochemistry. The main object of this project is mainly to consider the potential of K-mineral production along with ongoing salt production. Seven hundred and four samples were taken and partially analyzed for the main cations and anions. Surface water (0.5 m. depth) was analyzed for Na, K, Mg, Ca, Br and Li, and averaged 87.118 g/lit, 1.48 g/lit, 4.82 g/lit, 4.54 g/lit, 1.19 ppm and 12.7 ppm respectively for the western half of the lake. Sodium ranged between 84 to 91.2 g/lit, and showed higher concentrations in the south than in the north. This unexpected result may be caused by shallower depth in the south and a higher net evaporation effect. Calcium ranged between 4.2 to 5 g/lit, apparently slightly higher in the north. K is higher in the south, possibly due to rivers entering from south that may carry slightly higher K in solution. In the middle-range samples (0.5-5 m.), K averaged 1.43 g/lit and ranged from 1.40 to 1.46 g/lit. At this intermediate depth the distribution of K is clearly higher to the south of the causeway that is currently under construction. It is not clear whether this increase is the effect of the causeway or the effect of the salty Aji-Chay River to the east, and the Khoy salt domes to the north of the lake. At depth (5 m-10 m), K averaged 1.48 g/lit and ranged from 1.4 to 1.49 g/lit, differing only in the second decimal from the

  3. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis

    2000-01-01

    In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, physics, biology, and engineering, including the arrangement of soap bubbles in foam, atoms in a crystal, the architecture of the bee''s honeycomb, and the structure of the Giant''s Causeway. Using an informal style and with key references, the book also includes brief accounts of the lives of many of the scientists who devoted themselves to problems of packing over many centuries, together with wry comments on their efforts. It is an entertaining introduction to the field for both specialists and the more general public.

  4. Alexander the Great's tombolos at Tyre and Alexandria, eastern Mediterranean

    Science.gov (United States)

    Marriner, N.; Goiran, J. P.; Morhange, C.

    2008-08-01

    Tyre and Alexandria's coastlines are today characterised by wave-dominated tombolos, peculiar sand isthmuses that link former islands to the adjacent continent. Paradoxically, despite a long history of inquiry into spit and barrier formation, understanding of the dynamics and sedimentary history of tombolos over the Holocene timescale is poor. At Tyre and Alexandria we demonstrate that these rare coastal features are the heritage of a long history of natural morphodynamic forcing and human impacts. In 332 BC, following a protracted seven-month siege of the city, Alexander the Great's engineers cleverly exploited a shallow sublittoral sand bank to seize the island fortress; Tyre's causeway served as a prototype for Alexandria's Heptastadium built a few months later. We report stratigraphic and geomorphological data from the two sand spits, proposing a chronostratigraphic model of tombolo evolution.

  5. The architectonic encoding of the minor lunar standstills in the horizon of the Giza pyramids.

    Science.gov (United States)

    Hossam, M. K. Aboulfotouh

    The paper is an attempt to show the architectonic method of the ancient Egyptian designers for encoding the horizontal-projections of the moon's declinations during two events of the minor lunar standstills, in the design of the site-plan of the horizon of the Giza pyramids, using the methods of descriptive geometry. It shows that the distance of the eastern side of the second Giza pyramid from the north-south axis of the great pyramid encodes a projection of a lunar declination, when earth's obliquity-angle was ~24.10°. Besides, it shows that the angle of inclination of the causeway of the second Giza pyramid, of ~13.54° south of the cardinal east, encodes the projection of another lunar declination when earth's obliquity-angle reaches ~22.986°. In addition, it shows the encoded coordinate system in the site-plan of the horizon of the Giza pyramids.

  6. Summary of 1987 and 1988 manatee aerial surveys at Kennedy Space Center

    Science.gov (United States)

    Provancha, Jane A.; Provancha, Mark J.

    1989-01-01

    Aerial surveys of manatees conducted since 1977 at Kennedy Space Center (KSC) have provided a very useful and cost effective monitoring tool in the assessment of abundance and distribution of manatees in the northern Banana River. Data collected in the mid 1980's as part of the KSC Environmental Monitoring Program indicated that the numbers of manatees utilizing the northern Banana River had increased dramatically from earlier years and that the animals appeared to have changed their distribution patterns within the area as well (Provancha and Provancha 1988). United States Fish and Wildlife Service (USFWS) and Florida Department of Natural Resources (FLDNR) conducted bimonthly aerial surveys in 1986 for the entire Florida east coast. Their data clearly show that the Banana River has the highest concentration of manatees during the non-winter months when compared to all other segments of the east coast surveys (B. Wiegle/FLDNR, unpublished data). They further show that, in spring, an average of 71 percent of the manatees in Brevard county were located in the Banana River. During that period 85 percent of the animals were north of the NASA Causeway (State Road (SR) 402) in the KSC security zone. These data indicate the importance of the KSC waters to the Florida east coast manatee population. We reinitiated KSC surveys in 1987 to document distributions and numbers of manatees during the spring influx. Aerial censuses were continued throughout the year in 1988 and this report provides a summary of our findings for the two years.

  7. The Writing on the Wall: National and Global Implications of the Ruling Chinese Communist Party’s Domestic and Foreign Policies

    Directory of Open Access Journals (Sweden)

    Emile Kok-Kheng Yeoh

    2016-04-01

    Full Text Available The December 201 5 crackdown on labour activists was the culmination of a year of the Chinese Communist Party regime’s war on China’s civil society kicked off by of the arrests of the “Feminist Five” in March followed by the infamous crackdown on civil rights lawyers that began on 5th July and lasted till August. At around the same time, from mid-October to end of December 2015, five owners and staff members of Hong Kong’s Mighty Current publishing company and Causeway Bay bookshop which respectively publishes and selling politically dissident books banned by China disappeared under mysterious circumstances (including one while vacationing in Pattaya, Thailand, and another while inspecting warehouse in Hong Kong and reemerged in mainland China under the custody of the Chinese authorities. While these volatile incidents were unfolding domestically, the year also witnessed the continued rise of China’s economic might in the global system. With specific focus on the latest events unfolding from year 2015 to the present, this paper attempts to interpret such developments especially in terms of government policies with respect to the State’s relations with the civil society since the leadership transition from Hu-Wen to Xi-Li administration, the implications of the global reach of China’s economic might and soft power in this regard, as well as the current nature of the governing regime of the Chinese Communist Party.

  8. Studies Concerning Heat-Resisting Additives for Bitumens

    Directory of Open Access Journals (Sweden)

    Livia Groll

    2008-01-01

    Full Text Available The improvement of causeway’s bitumen adhesiveness is becoming a current practice in our country, especially when is used acid (siliceous aggregate. One of the most important properties of bitumen is its adhesiveness to aggregate, and this property determine the using of bitumen in causeways area. Usually the adhesiveness is defined as the capacity of a binder to cover an aggregate without dispersing itself when touching the water or the traffic aggressions. Therefore, the adhesiveness additives are products that improve the adhesiveness of the bitumen to a certain aggregate. The used additives – ADETEN type (A01 and A03 have a high stocking stability, a low toxicity degree toward the amine, diamine, polyamine-based additives and are liquid products perfectly compatible with all bitumens and easy to use, in comparison to the paste or solid additives, which must be made liquid to be used. But a very important condition, which must be fulfilled by these promoters is the heat-resisting condition.

  9. Influence of thermal loading on the ecology of intertidal algae

    International Nuclear Information System (INIS)

    Thermal effluents from the Maine Yankee Atomic Power Company (operating intermittently from October 1972 to December 1974) increased water temperatures in the discharge area by 7 to 150C. Plant operation and the removal of a causeway increased mixing and salinities in Montsweag Bay. Four small red algae immigrated into the area, but no species were lost from the system. Distribution and abundance patterns of the dominant algae, Ascophyllum nodosum and Fucus vesiculosus, were altered by the thermal discharge. The cover of F. vesiculosus decreased, whereas that of A. nodosum increased in 1973 but declined significantly in 1974. Reductions in biomass and percent cover were accompanied by changes in the growth dynamics of A. nodosum. Growth and survival in the discharge area were enhanced in 1973 but reduced in 1974. Growth was initiated earlier at all sites affected by the warm water. Plants at experimental sites not directly in the discharge channel grew at accelerated rates during the two years, but stressed plants in the discharge produced few or no viable apexes in 1974. The net effect has been a compression and reduction of intertidal algae into a narrower and less dense band

  10. Detailed magnetic survey at Dahshour archeological sites Southwest Cairo, Egypt

    Science.gov (United States)

    Mekkawi, Mahmoud; Arafa-Hamed, Tarek; Abdellatif, Tareq

    2013-06-01

    Dahshour area has recently shown a great potential of archeological findings. This was remarkable from the latest discovery of the causeway and the mortuary temple of the Pyramid of Amenemhat III using geophysical data. The main objective of the present work is to locate the buried archeological remains in the area of Dahshour, Southwest Cairo using magnetic survey for shallow investigations. Land magnetic data is acquired using proton magnetometer (two sensors) with a sensor separation of 0.8 m; i.e. gradiometer survey. The study area is located nearby the two known pyramids of Dahshour. The field data is processed and analyzed using Oasis Montaj Geosoft™ software. The processed data is presented in order to delineate the hidden artifacts causing the magnetic anomalies. The results indicated a distribution of the buried archeological features within the study area. These archeological features are detected according to the magnetic contrast between the magnetic archeological sources (such as mud bricks, basalt and granite) and the surroundings; mainly sandy soil. The delineated archeological features at Dahshour are probably dated back to the old kingdom having a depth reach up to 3.0 m. Consequently it is highly recommended to carry out excavation to precisely classify them and high light their nature and value.

  11. Bikini: Disposal of contaminated soil in Berm construction; Design and costs

    International Nuclear Information System (INIS)

    Since the levels of cesium-137 and strontium-90 in Bikini Island soil fall off exponentially (on average) with depth, the bulk of soil contamination can be removed directly by excavating the top 30 cm. Radiologically, the spoil is of low specific activity, and it can be handled without special precautions. However, the disposal of the spoil, totalling some 940,000 cubic yards plus vegetation, would pose something of a problem. Dumping into the lagoon (Bravo Crater) or ocean, presumably simple and effective measures, would not be legally permissible. A more practical alternative would employ the spoil to build a berm on the ocean-side of the island, or possibly a causeway between Bikini and Eneu Islands. The design of the proposed structures was reviewed at a conference held at the U.S. Army Waterways Experiment Station, August 19, 1985. It was concluded that further study was required (BARC 2). This has been done by Coastal Engineering Research center and the complete report is presented

  12. Google Earth: Inspiration and Instrument for the Study of Ancient Civilizations

    Directory of Open Access Journals (Sweden)

    Jaroslav Klokočník

    2011-12-01

    Full Text Available Satellite imaging is well known as a useful tool in many scientific disciplines and various applications.  Google Earth, with its free access, is now - thanks to increasing resolution and precision - such a tool. It can be very inspiring. It improves the visualization and dissemination of scientific data, and opens doors to new discoveries. For example, many Nasca geoglyphs are now visible to Google Earth and so are the orientations of Chinese pyramids, which appear to be laid out with the aid of a magnetic compass. Google Earth also infor-med us about the “new” archaeological locality Atzompa close to the well known “Monte Alban” near Oaxaca (Mexico, which we then visited (in March 2010. Google Earth can also “see” prehistoric causeways in Mesoamerica, “sacbeob” and in the Chaco valley (New Mexico. We find that Google Earth can save time and resources to researches significantly: before, during and after field works and measurements; we present examples.

  13. Remote Sensing in Archaeology: Visible Temporal Change of Archaeological Features of the Peten, Guatemala

    Science.gov (United States)

    Lowry, James D., Jr.

    1999-01-01

    The purpose of this archaeological research was two-fold; the location of Mayan sites and features in order to learn more of this cultural group, and the (cultural) preservation of these sites and features for the future using Landsat Thematic Mapper (TM) images. Because the rainy season, traditionally at least, lasts about six months (about June to December), the time of year the image is acquired plays an important role in spectral reflectance. Images from 1986, 1995, and 1997 were selected because it was felt they would provide the best opportunity for success in layering different bands from different years together to attempt to see features not completely visible in any one year. False-color composites were created including bands 3, 4, and 5 using a mixture of years and bands. One particular combination that yielded tremendously interesting results included band 5 from 1997, band 4 from 1995, and band 3 from 1986. A number of straight linear features (probably Mayan causeways) run through the bajos that Dr. Sever believes are features previously undiscovered. At this point, early indications are that this will be a successful method for locating "new" Mayan archaeological features in the Peten.

  14. Canadian Environmental Assessment Act screening report (draft) proposal for the Petitcodiac River Trial Gate Opening Project

    International Nuclear Information System (INIS)

    A Memorandum of Agreement has been signed by the federal government and the Government of New Brunswick concerning a trial opening of the Petitcodiac River Causeway gates at Riverview, New Brunswick. The structure has significantly impeded upstream and downstream diadromous fish migration. Several renovations have been undertaken to solve the problem. Environment Canada and the Department of Fisheries and Oceans have conducted an environmental assessment to address relevant environmental issues concerning the trial gate opening. This report is the draft of the environmental assessment, providing a description of the scope, time table and methodology of the assessment and a list of the various consultations undertaken during the assessment. The project is expected to begin as early as April 1, 1999, with a pre-trial flushing and the drawdown of the head pond. Once the river flow is low enough to allow the management of the gates, the trial gate will be opened. The project will end with the refilling of the head pond, possibly as late as November 1999. 30 refs., 5 tabs., 1 append

  15. Discovering the Ancient Maya from Space

    Science.gov (United States)

    Sever, T. L.

    2008-01-01

    The Pet6n region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use of limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  16. Overseas Voter Mobilisation in Singapore: Implications from Malaysia’s 13th General Election

    Directory of Open Access Journals (Sweden)

    James Gomez

    2013-01-01

    Full Text Available This paper discusses voter mobilisation and other election-related activities of Malaysian voters living, studying and working in Singapore in the context of Malaysia’s 13th general election (GE13. According to the World Bank, nearly 400,000 Malaysians reside in the city-state. Thus these figures represent a significant Malaysian voter pool based in Singapore. Efforts to mobilise these voters for general elections or other causes have political implications for both countries, which became apparent following Singapore-based Malaysians’ activities to encourage Malaysians to return home to cast their votes during the 13th general election. Singapore’s strict public assembly laws led to several legal issues related to the voter mobilisation and election campaign activities undertaken by Malaysians in the city-state. These legal issues became a source of friction between the two countries during the elections as government leaders and authorities on both sides of the causeway accused the other of interfering in domestic political matters. Given the growing number of Malaysians in Singapore and the likely repeat of Malaysian voter mobilisation activities in Singapore in the run-up to the fourteenth general election (GE14 in 2018, issues related to the election activities of Malaysian voters in Singapore stand to be another set of factors that will shape the health of bilateral relations between these two countries.

  17. Human-induced marine ecological degradation: micropaleontological perspectives.

    Science.gov (United States)

    Yasuhara, Moriaki; Hunt, Gene; Breitburg, Denise; Tsujimoto, Akira; Katsuki, Kota

    2012-12-01

    We analyzed published downcore microfossil records from 150 studies and reinterpreted them from an ecological degradation perspective to address the following critical but still imperfectly answered questions: (1) How is the timing of human-induced degradation of marine ecosystems different among regions? (2) What are the dominant causes of human-induced marine ecological degradation? (3) How can we better document natural variability and thereby avoid the problem of shifting baselines of comparison as degradation progresses over time? The results indicated that: (1) ecological degradation in marine systems began significantly earlier in Europe and North America (∼1800s) compared with Asia (post-1900) due to earlier industrialization in European and North American countries, (2) ecological degradation accelerated globally in the late 20th century due to post-World War II economic growth, (3) recovery from the degraded state in late 20th century following various restoration efforts and environmental regulations occurred only in limited localities. Although complex in detail, typical signs of ecological degradation were diversity decline, dramatic changes in total abundance, decrease in benthic and/or sensitive species, and increase in planktic, resistant, toxic, and/or introduced species. The predominant cause of degradation detected in these microfossil records was nutrient enrichment and the resulting symptoms of eutrophication, including hypoxia. Other causes also played considerable roles in some areas, including severe metal pollution around mining sites, water acidification by acidic wastewater, and salinity changes from construction of causeways, dikes, and channels, deforestation, and land clearance. Microfossils enable reconstruction of the ecological history of the past 10(2)-10(3) years or even more, and, in conjunction with statistical modeling approaches using independent proxy records of climate and human-induced environmental changes, future

  18. Foreword – Upon the Second Anniversary of Occupy Campaign / Umbrella Movement in Hong Kong: Essays in Honour of a Pro-Democracy Sociopolitical Movement

    Directory of Open Access Journals (Sweden)

    Emile Kok-Kheng Yeoh

    2016-08-01

    Full Text Available 28th September 2016 is the second anniversary of the Occupy Campaign / Umbrella Movement in Hong Kong. It is also the last anniversary of the said sociopolitical event, which arguably represented a most important milestone in Hong Kong’s post-1997 development, before 1st July 2017 that will mark the 20th anniversary of the “Handover”. It was on 28th September two years ago that pro-democracy protestors occupy the Admiralty, Causeway Bay, Mong Kok and Tsim Sha Tsui areas of Hong Kong in a momentous campaign initially planned out earlier by the “Occupy Central with Love and Peace” (OCLP movement, but launched earlier than scheduled when overtaken by the development of events, metamorphosed into unprecedented scale of demonstrations at multiple locations and was transformed into what was dubbed by the world media as the “Umbrella Movement” when umbrellas, which protestors were using to protect themselves when the police attacked them with tear gas and pepper spray, became a symbol of the occupation campaign. To commemorate this second anniversary of this Occupy Campaign a.k.a. Umbrella Movement, the present issue of Contemporary Chinese Political Economy and Strategic Relations: An International Journal entitled From Handover to Occupy Campaign: Democracy, Identity and the Umbrella Movement of Hong Kong represents a collection of specially selected articles focusing on this momentous event, its background of determining factors, theoretical and ideological underpinnings, as well as its implications for the future of the Hong Kong people’s valiant struggle for democracy against the backdrop of the formidable odds, since the 1997 “Handover”, as being under the sovereignty of a gigantic country with a entrenched ruling Chinese Communist Party (CCP6 regime that has no foreseeable intention of allowing for a transition from the present repressive one-party dictatorship to liberal democracy that would respect political freedom and

  19. Quantifying Ancient Maya Land Use Legacy Effects on Contemporary Rainforest Canopy Structure

    Directory of Open Access Journals (Sweden)

    Jessica N. Hightower

    2014-11-01

    Full Text Available Human land use legacies have significant and long-lasting ecological impacts across landscapes. Investigating ancient (>400 years legacy effects can be problematic due to the difficulty in detecting specific, historic land uses, especially those hidden beneath dense canopies. Caracol, the largest (~200 km2 Maya archaeological site in Belize, was abandoned ca. A.D. 900, leaving behind myriad structures, causeways, and an extensive network of agricultural terraces that persist beneath the architecturally complex tropical forest canopy. Airborne LiDAR enables the detection of these below-canopy archaeological features while simultaneously providing a detailed record of the aboveground 3-dimensional canopy organization, which is indicative of a forest’s ecological function. Here, this remote sensing technology is used to determine the effects of ancient land use legacies on contemporary forest structure. Canopy morphology was assessed by extracting LiDAR point clouds (0.25 ha plots from LiDAR-identified terraced (n = 150 and non-terraced (n = 150 areas on low (0°–10°, medium (10°–20°, and high (>20° slopes. We calculated the average canopy height, canopy openness, and vertical diversity from the LiDAR returns, with topographic features (i.e., slope, elevation, and aspect as covariates. Using a PerMANOVA procedure, we determined that forests growing on agricultural terraces exhibited significantly different canopy structure from those growing on non-terraced land. Terraces appear to mediate the effect of slope, resulting in less structural variation between slope and non-sloped land and yielding taller, more closed, more vertically diverse forests. These human land uses abandoned >1000 years ago continue to impact contemporary tropical rainforests having implications related to arboreal habitat and carbon storage.

  20. EL DESCUBRIMIENTO DE UN CEMENTERIO DE ÉLITE EN EL CAÑO: INDICIOS DE UN PATRÓN FUNERARIO EN EL VALLE DE RÍO GRANDE, COCLÉ, PANAMÁ (The Discovery of an Elite Cemetery at El Caño: Traces of a Mortuary Pattern in Río Grande Valley, Coclé, Panama

    Directory of Open Access Journals (Sweden)

    Julia Mayo

    2013-11-01

    Full Text Available El Caño, situado en la provincia de Coclé (Panamá, es un yacimiento arqueológico conocido por su singular estilo escultórico y por contener estructuras arqueológicas de piedra. Recientemente se han descubierto en este lugar cuatro tumbas de personas de élite con ricos ajuares, fechadas entre el 700 y el 1000 d. C. Estas son coetáneas a las halladas en el cercano Sitio Conte, una necrópolis en la que se encontraron, hace más de ochenta años, las primeras evidencias arqueológicas de la complejidad de las sociedades precolombinas del istmo. La existencia en Sitio Conte y El Caño de elementos semejantes —basaltos columnarios dispuestos en hileras, calzadas y ricas tumbas— organizados además de forma similar, indica la posibilidad de la existencia de un patrón funerario en el valle de Río Grande. ENGLISH: El Caño, located in the Coclé province, Panama, is known for its unique stone sculptural style and stone structures. Recently four lavish burials have been discovered. Dated between 700 and 1000 AD, they are broadly coeval with similar mortuary features at nearby Sitio Conte, a cemetery which provided the first archaeological evidence for the sumptuous wealth of Panamanian chiefdoms more than eighty years ago. The existence in Sitio Conte and El Caño of similar elements—alignments of basalt columns, causeways and rich tombs—with a similar spatial organization, indicates the possibility of the existence of a mortuary pattern in Río Grande.

  1. The microbial ecology of the Great Salt Lake.

    Science.gov (United States)

    Post, F J

    1977-06-01

    The Great Salt Lake is actually two lakes. A highly saline (330-gml(-1)) northern arm and a moderately saline (120-gml(-1)) southern arm separated by a semipermeable rock causeway. The lake, particularly the northern arm, has a massive accumulation of organic matter resulting from more than 100,000 years of productivity, cycling from a freshwater to a saline lake, plus the influence of human industry and agriculture in more recent times. The north arm planktonic and attached community consists principally of, in order of biomass: bacteria of at least two genera,Halobacterium andHalococcus; two algae,Dunaliella salina andD. viridis; the brine shrimp,Anemia salina; and, two species of brine fly,Ephydra gracilis andE. hians and possibly one more species. The algae and the bacteria appear to depend on each other for nutrients. The bacteria use organic matter produced by the algae and the algae use ammonia produced by the bacteria and possibly the brine shrimp. The production of ammonia appears to be the rate-limiting step although there is no shortage of other forms of nitrogen in the north arm. Based on aquarium studies, the potential for biomass production of algae and bacteria is much higher than actually observed in the north arm, leading to the postulation of two additional factors controlling population; the grazing of the algae by invertebrates with the excretion of compounds rich in nitrogen, and the effect of a low habitat temperature and winter cold on the bacteria, reducing their metabolic activities to nearly zero. Some aspects of the various organisms and their metabolism are discussed. A comparison is made with recent work on the Dead Sea. PMID:24233467

  2. Space Station view of the Pyramids at Giza

    Science.gov (United States)

    2002-01-01

    One of the world's most famous archaeological sites has been photographed in amazing detail by the astronauts onboard Space Station Alpha. This image, taken 15 August, 2001, represents the greatest detail of the Giza plateau captured from a human-occupied spacecraft (approximate 7 m resolution). Afternoon sun casts shadows that help the eye make out the large pyramids of Khufu, Khafre and Menkaure. Sets of three smaller queens' pyramids can be seen to the east of the Pyramid of Khufu and south of the Pyramid of Menkaure. The light-colored causeway stretching from the Mortuary Temple at the Pyramid of Khafre to the Valley Temple near the Sphinx (arrow) can also be seen. Because it is not tall enough to cast a deep shadow, the Sphinx itself cannot readily be distinguished. Although some commercial satellites, such as IKONOS, have imaged the Pyramids at Giza in greater detail (1 m resolution), this image highlights the potential of the International Space Station as a remote sensing platform. A commercial digital camera without space modifications was used to obtain this picture. Similarly, a variety of remote sensing instruments developed for use on aircraft can potentially be used from the Space Station. Currently, all photographs of Earth taken by astronauts from the Space Shuttle and Space Station are released to the public for scientific and educational benefit and can be accessed on the World Wide Web through the NASA-JSC Gateway to Astronaut Photography of Earth (http://eol/jsc.nasa.gov/sseop). Image ISS003-ESC-5120 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center (http://eol.jsc.nasa.gov).

  3. Lake Urmia Shrinkage and its Effect on the Settlement of the Surrounding Areas Investigated Using Radar and Optical Satellite Images

    Science.gov (United States)

    Motagh, M.; Shamshiri, R.; Hosseini, F.; Sharifi, M. A.; Baes, M.

    2014-12-01

    With a total area of more than 50000 km^2 Lake Urmia basin in northwest of Iran was once one of the biggest salt lakes in the world. The lake has been shrinking in the recent years, losing in turn dramatically its area. A lot of factors have been attributed to this shrinking including construction of dams on the rivers feeding the lake and overexploitation of groundwater for agricultural and industrial purposes. In this study we first utilized time-series analysis of Landsat images to precisely quantify surface changes in the region between 1984 and 2013. We then analyzed a number of SAR images from 2002 to 2014 including 30 ASAR images from Envisat, 10 PALSAR images from ALOS, and more than 35 TerraSAR-X (TSX) in both Stripmap and Spot modes to assess surface ground deformation. Ground deformation was evaluated for both agricultural regions around the lake and Lake Urmia Causeway (LUC), connecting two provinces of East and West Azerbaijan on both sides of the lake. The InSAR results of the LUC embankments is further investigated using Finite Element approach to better understand the relation between soil parameters, lake level changes and settlement of the LUC. The classification results using optical imagery analysis show that human and anthropogenic activities have resulted in shrinking of Lake Urmia by more than 60% over the past 30 years. The agricultural areas around the lake are dominated by ground subsidence reaching to 10 cm/yr in places. The LUC embankments also show large deformation with peak settlement of more than 5 cm/yr over the last decade. FEM simulation shows that consolidation due to dissipation of excess pore pressure in embankments can satisfactorily explain its surface deformation.

  4. Open Pit Water Control Safety A Case Of Nchanga Open Pit Mine Zambia

    Directory of Open Access Journals (Sweden)

    Silwamba C

    2015-08-01

    Full Text Available Abstract Mining in Chingola Zambia started underground in 1931 and was catastrophically flooded and closed. The present Nchanga Underground Mine NUG started in 1937. The Nchanga Open Pit NOP mine started in 1955 situated to the west of NUG and partially overlying it. Open pit water control safety operations in the Nchanga-Chingola area have successfully enabled the safe extraction of millions of tonnes of copper ore annually over the past 60 years from NUG mining as well as the NOP. At the start Nchanga mining license surface already had NUG and many watershed divides with the Nchanga and Chingola streams being the main streams feeding into Zambias second largest river Kafue river and 42 of the year was characterised by heavy rains ranging between 800mm to 1300mm per annum. In this paper the presence of very significant amounts of seasonal rain and subsurface water in the mining area was identified as both a curse and a blessing. An excess in seasonal rain and subsurface water would disrupt both open pit and underground mining operations. In order for NOP to be operated successfully stable and free from flooding coping water management tactics were adopted from 1955 to 2015 including 1. Underground mine pump chamber pumping system 2. Piezometer instrumented boreholes 3. Underground mine 1500-ft sub-haulage east borehole dewatering beneath the open pit 4. Nchanga and Chingola stream diversionary tunnel and open drains 5. Nchanga stream causeway and embankment dam in the Matero School Golf Club area 6. Pit perimeter borehole pumping 7. Outer and inner pit perimeter drains and bund walls 8. In-pit ramp side drains 9. In-pit sub-horizontal borehole geo-drains and water and 10. Pit bottom sump pumps. Application of grout curtains along the Vistula River Poland was noted as a possibility in the right circumstances although it had never been used at Nchanga Open Pit. An additional conclusion was that forward health safety and environmental end

  5. Mississippi Delta, Radar Image with Colored Height

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for the animation About the animation: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar Topography Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments. About the image: The geography of the New Orleans and Mississippi delta region is well shown in this radar image from the Shuttle Radar Topography Mission. In this image, bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations. New Orleans is situated along the southern shore of Lake Pontchartrain, the large, roughly circular lake near the center of the image. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest over water highway bridge. Major portions of the city of New Orleans are below sea level, and although it is protected by levees and sea walls, flooding during storm surges associated with major hurricanes is a significant concern. Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter

  6. Application of Sediment Trend Analysis in the Examination of Sediment Transport Dynamics of Missisquoi Bay

    Science.gov (United States)

    Kraft, M. P.; Manley, P.; Singer, J.; Manley, T.; McLaren, P.

    2013-12-01

    Missisquoi Bay is located between Vermont and Quebec in the northeast sector of the Restricted Arm of Lake Champlain. The average depth of the Bay is slightly less than 3 meters with a surface area covering 77.5 km2. The Bay receives water from eastern and western catchment basins, most notably via the Missisquoi, Rock, and Pike Rivers. Circulation within Missisquoi Bay has been altered by the construction of railroad causeways in the late 19th century and highway construction in the early 20th century. Over the past several decades there have also been changes in land-use practices, including the intensification of agriculture, increased animal husbandry, and urbanization. As a consequence of construction and changing land use, loadings of nitrogen and phosphorus to the Bay have increased seasonal oxygen depletion causing eutrophication. Since monitoring began in 1992, Missisquoi Bay has displayed the highest mean total phosphorus concentrations and chlorophyll a concentrations in Lake Champlain. Various efforts have taken place to reduce nutrient loading to Missisquoi Bay, but persistent release of phosphorus from bottom sediments will continue to delay for decades the recovery from nutrient diversion. To better understand the causes and timing of eutrophication in Missisquoi Bay, one component of a 5-year integrated VT EPSCoR - RACC program included an examination of N and P loadings and their distribution throughout the Bay. Internal circulation patterns are also being studied. To determine the pattern of net sediment transport and determine sediment behavior (erosion and accretion), a Sediment Trend Analysis (STA) was performed using 369 grab samples collected in the Bay. Grain size distributions for the surface sediment samples were determined using a Malvern Mastersizer 2000 particle size analyzer. Sediment maps showing the proportion of gravel, sand, and mud show that near major river distributaries sand-sized sediment was dominant with muds becoming more

  7. Venice, Italy

    Science.gov (United States)

    2002-01-01

    Four hundred bridges cross the labyrinth of canals that form the 120 islands of Venice, situated in a saltwater lagoon between the mouths of the Po and Piave rivers in northeast Italy. All traffic in the city moves by boat. Venice is connected to the mainland, 4 kilometers (2.5 miles) away, by ferries as well as a causeway for road and rail traffic. The Grand Canal winds through the city for about 3 kilometers (about 2 miles), dividing it into two nearly equal sections. According to tradition, Venice was founded in 452, when the inhabitants of Aquileia, Padua, and several other northern Italian cities took refuge on the islands of the lagoon from the Teutonic tribes invading Italy at that time.This image was acquired on December 9, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.Dr. Anne Kahle at NASA

  8. New Orleans Topography, Radar Image with Colored Height

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for the animation About the animation: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar Topography Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments. About the image: The city of New Orleans, situated on the southern shore of Lake Pontchartrain, is shown in this radar image from the Shuttle Radar Topography Mission (SRTM). In this image bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the SRTM mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations. New Orleans is near the center of this scene, between the lake and the Mississippi River. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest overwater highway bridge. Major portions of the city of New Orleans are actually below sea level, and although it is protected by levees and sea walls that are designed to protect against storm surges of 18 to 20 feet, flooding during storm surges associated with major hurricanes is a significant concern. Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers

  9. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    Science.gov (United States)

    Naftz, D.; Angeroth, C.; Kenney, T.; Waddell, B.; Darnall, N.; Silva, S.; Perschon, C.; Whitehead, J.

    2008-01-01

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6??? decrease in ??15N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in ??15N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing ??15N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO42 - reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH3Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH3Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves generated during sustained wind events can temporarily mix the

  10. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    International Nuclear Information System (INIS)

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6 per mille decrease in δ15N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in δ15N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing δ15N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO42- reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH3Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH3Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves generated during sustained wind events can temporarily

  11. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    Energy Technology Data Exchange (ETDEWEB)

    Naftz, David [US Geological Survey, Salt Lake City 84119, UT (United States)], E-mail: dlnaftz@usgs.gov; Angeroth, Cory; Kenney, Terry [US Geological Survey, Salt Lake City 84119, UT (United States); Waddell, Bruce; Darnall, Nathan [US Fish and Wildlife Service, Salt Lake City, UT (United States); Silva, Steven [US Geological Survey, Menlo Park, CA (United States); Perschon, Clay [Utah Division of Wildlife Resources, Salt Lake City, UT (United States); Whitehead, John [Utah Department of Environmental Quality, Salt Lake City, UT (United States)

    2008-06-15

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6 per mille decrease in {delta}{sup 15}N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in {delta}{sup 15}N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing {delta}{sup 15}N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO{sub 4}{sup 2-} reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH{sub 3}Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH{sub 3}Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves

  12. PREFACE: Kelvin and Ireland

    Science.gov (United States)

    Flood, Raymond; McCartney, Mark; Whitaker, Andrew

    2009-07-01

    frequent visitor. While the most celebrated example of his engineering work was his massive contribution to the Atlantic telegraph cable, and his maritime and other inventions were used throughout the world, he was especially pleased to contribute to two important technical accomplishments in the north of Ireland, the occulting Holywood lighthouse and the Giant's Causeway tramway. Kelvin's interest in Ireland came again to the fore in the Home Rule debate at the end of the nineteenth century; Kelvin was vehemently opposed to Home Rule and became a passionate member of the Liberal Unionist party, a crucial factor in his becoming a peer. Accounts of these aspects of Kelvin's involvement with Ireland are given in our first four papers. The fifth paper was particularly appropriate for the meeting. It describes how an important contribution of Kelvin on optimal packing has been improved in Ireland by the speaker, Denis Weaire, himself, and how the result has been seen by the whole world in Beijing. Finally there is a discussion of Kelvin's place in the story of Irish science. There have been many highly accomplished Irish scientists, and the meeting showed clearly that Kelvin certainly deserves to be included among the greatest. Acknowledgments The meeting was the second regional event of the Institute of Physics (IOP) in Ireland, the first being the meeting on John Desmond Bernal: Science and Society held in Limerick in June 2006 and published in the same series as this volume. The meeting also benefited from the support of many bodies and institutions. We would like to thank the committee of the IOP in Ireland for providing finance and also giving their full support. We would particularly mention Vincent Casey, the Chair, who also chaired the afternoon session, Emma Sokell, the Secretary, and Denise Gabuzda and Kevin McGuigan, past and present Treasurers. We would also thank Sheila Gilheany and Alison Hackett for general help and encouragement, including assisting the

  13. The Costa Maya:  Evolution of a Touristic Landscape La Costa Maya : évolution d'un paysage touristique La Costa Maya : evolución de un paisaje turístico

    Directory of Open Access Journals (Sweden)

    Klaus J. Meyer-Arendt

    2010-06-01

    ecotourism.  Development so far has been concentrated in Puerto Costa Maya, where a cruise ship pier and terminal were built in 2001.  The nearby beach resort (balneario of Majahual became dependent upon the 10-12 shiploads of tourists that descended upon it every week.  In spite of big development plans, the more remote beaches of the Costa Maya cater to fewer, but well-heeled ecotourists and dive tourists.  Hurricane Dean made landfall in August 2007 as a category-5 storm, and economic recovery only began in late 2008 when the cruise ship pier re-opened and Majahual rebuilt.  As of late 2009, the cruise-ship traffic had still not recovered to pre-Dean levels, and a global recession coupled with swine-flu and drug violence scares has lowered U.S. tourism to Mexico.  To what degree new tourism infrastructure such as an international airport at Tulum, a proposed causeway from Chetumal to the beach, and a new resort complex at Xahuayxel will stimulate tourism on the Mexican Costa Maya and eventually lead to a coastal highway link with San Pedro, Belize is still unknown.

  14. Editorial: Is This Any Way to Develop Policy?

    Directory of Open Access Journals (Sweden)

    Michael H. Miner

    2007-06-01

    investigation. Nor were they enacted after considering what the empirical research available in the mid to late 1990’s told us about sexual crimes and the effectiveness of sexual offender treatment. They were enacted to respond to public outcry following terrible, but anomalous, incidents. In fact, while each new law was justified by the high risk posed by repeat sex offenders, the empirical data indicated that at the time these laws were enacted, the rates of child sexual abuse were declining in the United States (Finkelhor & Jones, 2006 and the risk posed by convicted, identified sexual offenders was, and currently remains, actually quite low – ranging from a high of 24% (Harris & Hanson, 2004 to 5.3% (Bureau of Justice Statistics, 2003.The above process continues, unabated, here in the United States. We keep coming up with new ideas, such as residence restrictions, which have resulted in parolees in Florida living under a causeway and registered sexual offenders in Iowa living at interstate rest stops. Such residences would appear to increase public risk, rather than protect the public. Sex offender treatment, in such circumstances, would certainly appear to be a waste of time and resources, in that individuals concerned about where they can live and whether they can get a job, are in no place to work on the types of issues addressed by most treatment interventions. However, with each new heinous incident, our law makers do not appear to consider the possibility that the already enacted legislation is at best useless and at worst iatrogenic, they simply assume that the laws are not strict enough and must be “strengthened.” Thus, we in the U.S.A find ourselves in an environment where sexual offenders are society’s worst villains (although that might change now that our Federal government seems more focused on terrorists, they are all the same, and they will always be dangerous. Any suggestion that this is not the case, even though all of the available data indicate