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1

Water regulation in aestivating snails  

Microsoft Academic Search

Aestivating snails form abundant lamellate vesicles in the cells of the mantle collar, an epithelium known to regulate the rate at which water is lost from its surface. Since lamellate vesicles are much reduced in hydrated mantle tissue of recently stimulated animals it is tentatively concluded that the vesicles, and their contents, form a barrier to water movement within these

P. F. Newell; J. Machin

1976-01-01

2

Snail Destabilizes Cell Surface Crumbs3a  

PubMed Central

During Epithelial to Mesenchymal Transition (EMT), cells modulate expression of proteins resulting in loss of apical-basal polarity. Effectors of this EMT switch target the polarity protein Crumbs3a, a small transmembrane protein that is essential for generation of the apical membrane and tight junctions of mammalian epithelial cells. We previously showed that the Crumbs3 gene is a direct target of transcriptional regulation by Snail, a potent inducer of EMT. However, Snail has also been shown to have multiple non-transcriptional roles, including regulation of cell adhesion, proliferation and survival. Using SNAP-tag labeling, we determined that cell surface Crumbs3a has a half-life of approximately 3 hours and that this cell surface half-life is significantly reduced when EMT is induced by Snail. We further observe that Snail induces differential glycosylation of Crumbs3a, including sialylation, suggesting a mechanism by which Crumbs3a may be destabilized. These results indicate that Crumbs3a is a post-translational target of Snail, in addition to being a transcriptional target. We conclude that Snail’s ability to post-translationally modify and destabilize Crumbs3a augments the depolarizing process of EMT.

Harder, Jennifer L.; Whiteman, Eileen L.; Pieczynski, Jay N.; Liu, Chia-Jen; Margolis, Ben

2012-01-01

3

The microstructures of biomineralized surfaces: a spectroscopic study on the exoskeletons of fresh water (Apple) snail, Pila globosa.  

PubMed

In view of the importance in understanding biomineralization processes in different molluskan species, the common fresh water apple snail Pila globosa in Indian origin was taken to explore its mineralized exoskeleton structures. The detailed structural studies of the exoskeletons of P. globosa have been undertaken. The isolated layers present in these shells were studied by electron paramagnetic resonance (EPR), optical absorption, and infrared spectral techniques. The EPR spectra of the organic protein layer periostracum show the characteristic signals corresponding to Fe(3+) ions at g = 4.1 and 2.0. The EPR spectra of the ostracum (middle) layer at room temperature gives a complicated spectrum consisting of a number of Mn(2+) signals of at least three sets due to the aragonite nature of the material. The results indicate the presence of the multivalent manganese ions, which undergo the redox mechanisms. The thermal variation of the EPR spectra show marked effect on these samples both in g-values and the basic spectral pattern. PMID:15249020

Prasuna, C P Lakshmi; Narasimhulu, K V; Gopal, N O; Rao, J Lakshmana; Rao, T V R K

2004-08-01

4

Supercharged Snails for Stream Ecology & Water-Quality Studies  

ERIC Educational Resources Information Center

Gill-breathing freshwater snails (Family "Pleuroceridae") are ecologically important, abundant in many streams in the United States, and easy to collect and maintain under classroom conditions. These snails can be used in classroom tests to demonstrate effects of pollutants on aquatic organisms. In more advanced classes, students can cage the…

Stewart, Arthur J.; Ryon, Michael G.

2003-01-01

5

Heat shock proteins (Hsp70) and water content in the estivating Mediterranean Grunt Snail (Cantareus apertus).  

PubMed

Pulmonate land snails often are able to estivate to survive dry hot seasons were water and food are scarce. The aperture of the shell is closed with an epiphragm, and metabolism is depressed to approximately one fourth of basal metabolism. We investigated a molecular aspect of estivation focussing on the heat shock protein 70 (Hsp70) stress response during estivation in the Mediterranean Grunt Snail Cantareus apertus. Sequences of a new inducible hsp70 and of actin are presented and expression of the hsp70 gene as well as Hsp70 protein content was measured in estivating animals. Both Hsp70 protein and mRNA do not show a significant change from the control, although there is a trend that hsp70 mRNA is less abundant in estivating specimens. After heat shock, the expression of hsp70 increased and a higher Hsp70 protein content was detected. Water relations were also investigated. After a period of 6 months in the dormant state, the snails contained 14% less water than active ones, implying a constricted protection against desiccation, compared to the desert snail Sphincterochila zonata, and a Mediterranean-type water economy. PMID:18579425

Reuner, Andy; Brümmer, Franz; Schill, Ralph O

2008-09-01

6

The Molluscicidal Activity of Melia azadirchta on The Fresh water snail Physa acuta ( Draparnaud , 1805 ) A snail Associated with habitat of Lymnaea auricularia ( L )  

Microsoft Academic Search

The molluscicidal effect of Melia azadirachta was evaluated against the fresh water snail Physa acuta at juvenile freshly hatched stage. Calculating values of different concentrations ( Lc50 - Lc90 ) showed that melia was toxic against juvenile stage . The use of Melia azadirchta fruit extract was considered as an effective control method for Physa acuta in Mosul area .

Talib Hussen Ali; Azhar Abul; Jabbar Hamed

7

A study on biological control of six fresh water snails of medical and veterinary importance.  

PubMed

This study evaluated the molluscicidal effect of Commiphora mnolmol oil extract (Myrrh), on control of six fresh water snails (Lymnaea natalensis, Bulinus truncatus, Biomphalaria alexandrina, Physa acuta, Melania tuberculata and Cleopatra bulimoides). Also, the extract effect on the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta was evaluated. Snails and egg masses were exposed at 16-20 degrees C to various concentrations (conc.). LD50 after 24 hours expo-sure were 264/132, 283/195, 230/252, 200/224, 241/246 & 241/246 ppm for young/adult of L. natalensis, B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and C. bulimnoides respectively. LDtoo after 24 hours exposure were 400/400 for L. natalensis, B. truncatus, B. alexandrina, M. tuberculata and C. bulimoides, and 300/300 for Ph. acuta. Also, complete mortality (100%) was achieved for the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta at concentrations of 300, 200, 300 & 400 ppm respectively. Lower concentrations gave the same results after longer exposure. LD100 of C. molmol oil extract (Myrrh) had a rapid lethal effect on the six snail species and their egg masses in high conc. of 300 & 400 ppm. Commiphora molmol is a promising plant to be included with the candidate plant molluscicides. The oil extract of this plant showed a remarkable molluscicidal activity against used snail species. PMID:19530615

Abd-Allah, Karim F; Negm-Eldin, Mohsen M; Saleh, Mohamed H; El-Hamshary, Azza M S; El-Gozamy, Bothina M R; Aly, Nagwa S M

2009-04-01

8

Survival of the faucet snail after chemical disinfection, pH extremes, and heated water bath treatments  

USGS Publications Warehouse

The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50??C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

Mitchell, A. J.; Cole, R. A.

2008-01-01

9

[Experimental study on the environmental fate of nitrogen in snail-macrophyte ecosystem for water purification].  

PubMed

A snail-macrophyte simulation system was built and isotope tracer technique was adopted to study the environmental fate of nitrogen in snail-macrophyte purification system, the results showed that: Vallisneria spiralis increased its wet weight by 580% and its number by 6.6 ramets, moreover, Vallisneria spiralis absorbed 1.07% 15N by the roots and 7.74% by stems and leaves, while Bellamya only absorbed 0.06%. And 5.73% 15N was retained in the sediment. Through analyzing of the results, it indicated that: in such simulation system, sediment was the main nutrition source for the growth of Vallisneria spiralis, which absorbed only few dissolved nitrogen from water; ammonium nitrogen in water was transformed mainly in the sediment-water interface, most of which was absorbed by Vallisneria spiralis, a small amount was removed through nitrification and denitrification, and the rest was kept by sediment; Vallisneria spiralis was final vector for removing nitrogen in the system, and Bellamya could also boost the growth of Vallisneria spiralis and strengthen the processes of nitrification and denitrification, thus promoting the nitrogen removal from the system indirectly. So, during the period of culture, rational allocation of snail-macrophyte structure in different stages plays an important role in controlling water quality in ponds. PMID:23379157

Zhou, Lu-Hong; Gu, Xiao-Hong; Zeng, Qing-Fei; Mao, Zhi-Gang; Gao, Hua-Mei; Sun, Ming-Bo

2012-12-01

10

Water balance and resistance to desiccation in rock-dwelling snails  

NASA Astrophysics Data System (ADS)

We have examined the resistance to desiccation among rock-dwelling land snails of various phylogenetic groups: Cristataria genezarethana (Clausiliidae), Rupestrella rhodia (Chondrinidae) and Levantina caesareana (Helicidae), all from the same location in Israel. L. caesareana was the most resistant and R. rhodia the least resistant to desiccation and C. genezarethana was of intermediate resistance. Differences in the rates of water loss during desiccation were determined mainly by rate of water loss during the first 2 days of desiccation. The high rates of water loss in rock-dwelling species exceed those of other snails in the Mediterranean habitat of Israel. However, snails collected in the field at the end of aestivation were in only a mild state of dehydration, suggesting that the rocky habitat protects its occupants against desiccation. We also suggest that among the rock-dwelling species, the protective role of the rock is more important in the more evolutionarily primitive genera (the chondrinid Rupestrella and the clausiliid Cristataria) and that physiological capacities are more effective in the more highly evolved helicid Levantina.

Arad, Zeev; Goldenberg, Shoshana; Heller, Joseph

1995-06-01

11

Snail Snooping.  

ERIC Educational Resources Information Center

Presents an activity in which students in grades 5-8 learn about snail reproduction by observing and charting the activities of land snails, freshwater snails, and slugs. Instructions to implement and extend the activity are provided. (MDH)

Miller, Dorothy

1993-01-01

12

Water vapour sorption by the pedal mucus trail of a land snail  

Microsoft Academic Search

The hydrophilicity of pedal mucus trails deposited by snails influences the settlement of marine organisms and can potentially influence the trailing and homing mechanisms of terrestrial snails. The composition of pedal mucus deposited as a trail on a solid substrate by the giant African land snail (Achatina marginata) has been probed non-invasively using infrared ellipsometry. The primary chemical groups in

B. J. Lincoln; T. R. E. Simpson; J. L. Keddie

2004-01-01

13

The effects of water quality and age on the acute toxicity of copper to the Florida apple snail, Pomacea paludosa.  

PubMed

Copper (Cu)-containing compounds have been used in Florida as fungicides, herbicides, and soil amendments, resulting in elevated Cu in the aquatic ecosystem. The Florida apple snail (Pomacea paludosa), a key species in south Florida, may be adversely affected by Cu. Water-quality parameters, such as hardness, dissolved organic carbon (DOC), pH, and alkalinity, affect metal bioavailability and toxicity in aquatic organisms; however, it is uncertain to what extent these factors affect Cu toxicity in the Florida apple snail. The research presented here characterized the acute (96-hour) toxicity of Cu in water to the Florida apple snail at various life stages and under different water-quality parameters. Cu was more toxic to juvenile than adult apple snails. There was no difference between the 96-hour LC(50) at pH 5.5 and 6.5; however, the 96-hour LC(50 )values at pH 7.5 and 8.5 were greater than at lower pHs. The decrease in Cu(2+) above pH 7, as predicted by the MINTEQ model, accounted for the pH effect. Cu toxicity decreased as DOC increased from 0.2 to 30 mg/L. Unlike other aquatic organisms, hardness had no effect on Cu toxicity to the Florida apple snail, suggesting another mechanism of toxicity. Whole-body tissue analysis indicated that the lethal body burden of 120-day-old snails exposed to Cu for 4 days was 30 mg/kg Cu dry weight. Multiple regression analysis indicated that Cu toxicity was a function of organism age, DOC, and pH. PMID:18180860

Rogevich, E C; Hoang, T C; Rand, G M

2008-05-01

14

Snail Tales  

NSDL National Science Digital Library

"Snail Tales" is an inquiry-based exploratory lesson for students to investigate learning and memory using common garden snails. This classroom laboratory is based on research by neuroscientists and best classroom practice.

Phelps, Cynthia L.; Willcockson, Irmgard U.; Houtz, Lynne

2004-04-01

15

/sup 45/Ca uptake from water by snails (Lymnaea vulgaris) in control and detergent-polluted samples  

SciTech Connect

A biostatic assay method involving /sup 45/Ca uptake into shells and tissues of snails (Lymnaea vulgaris) in 72 hr was developed to follow the effect of detergent-polluted water on ecosystems. There was a marked decrease in the /sup 45/Ca uptake by shells and tissues of linear alkyl benzene sulfonate-exposed animals as compared to controls. No change in /sup 45/Ca uptake was observed in dead shells, thereby excluding the possibility of passive exchange.

Misra, V.; Lal, H.; Viswanathan, P.N.; Murti, C.R.

1984-02-01

16

Snail Trails  

ERIC Educational Resources Information Center

The slime trails of snails lead the author's students to a better understanding of science as inquiry and the processes of science. During this five-day activity, students get up close and personal with one of her favorite creatures, the land snail. Students begin by observing the organism and recording their observations. After making initial…

Galus, Pamela

2002-01-01

17

Snails home  

NASA Astrophysics Data System (ADS)

Many gardeners and horticulturalists seek non-chemical methods to control populations of snails. It has frequently been reported that snails that are marked and removed from a garden are later found in the garden again. This phenomenon is often cited as evidence for a homing instinct. We report a systematic study of the snail population in a small suburban garden, in which large numbers of snails were marked and removed over a period of about 6 months. While many returned, inferring a homing instinct from this evidence requires statistical modelling. Monte Carlo techniques demonstrate that movements of snails are better explained by drift under the influence of a homing instinct than by random diffusion. Maximum likelihood techniques infer the existence of two groups of snails in the garden: members of a larger population that show little affinity to the garden itself, and core members of a local garden population that regularly return to their home if removed. The data are strongly suggestive of a homing instinct, but also reveal that snail-throwing can work as a pest management strategy.

Dunstan, D. J.; Hodgson, D. J.

2014-06-01

18

Causes of Late Pleistocene water level change in Lake Victoria, Equatorial East Africa, derived from clumped isotopes of land snails and fresh water mollusks. (Invited)  

NASA Astrophysics Data System (ADS)

Carbonate clumped isotope thermometry is based on the dependence of 13C-18O bond abundance in the carbonate lattice (measured as ?47) on the carbonate formation temperature. Most marine and freshwater biogenic carbonates are found to be in agreement with the clumped isotopes - temperature calibration. Clumped isotope thermometry is particularly useful in terrestrial environments where the interpretation of carbonate ?18O is limited due to difficulty in estimating the paleo-water isotopic composition. Clumped isotope-derived temperatures from land snails are generally higher than the ambient environmental temperatures, but show no evidence for disequilibrium. We attribute these higher body temperatures to snail eco-physiological adaptations through shell color, morphology, and behavior. We use the clumped isotope-derived temperatures in combination with shell ?18O to calculate snail body water ?18O composition. This parameter is interpreted as a paleo-hydrological indicator that reflects the isotopic composition of local precipitation modified by local evaporation. Rusinga and Mfangano Islands in Lake Victoria provide a unique opportunity to compare extant species of modern and fossil freshwater mollusks and land snails from the same location to examine lake paleo-hydrology. This location is particularly interesting as Lake Victoria itself is the main source of rain-water in the region such that the isotopic composition of land snail body water can be related back to the source waters. We combine clumped isotope and oxygen isotope measurements of both freshwater mollusks and land snails to examine the water balance of the lake, testing hypotheses about the mechanism of a significant rise in lake level in Lake Victoria ~35 - 40 ka BP. Outcrops of paleo-beach deposits ~18 m above the modern day lake level indicate high water stands at ~35-40 ka BP. Based on water balance models for Lake Victoria, an increase in lake level of this magnitude could be driven by local mean annual precipitation that is significantly greater than modern. However, this is inconsistent with regional climate reconstructions. This suggests that either lake level was controlled by non-climatic factors, or that local climate in the Lake Victoria basin was different than regional patterns of climate across eastern Africa. We use oxygen and clumped isotopes of modern and fossil shells (Corbicula sp., Melanoides sp. and Bellamya unicolor) from this 18 m beach outcrop on Mfangano Island to (1) compare with modern lake water ?18O values and (2) calculate paleo-water compositions. We combine these results with calculated snail body water ?18O composition (using oxygen and clumped isotopes) of land snails (Limicoloria cf. martensiana) from Rusinga and Mfangano Islands, to study hydrological changes of Lake Victoria. We use these data to evaluate the relative importance of climate change and tectonics as mechanisms for the Late Pleistocene expansion of Lake Victoria.

Zaarur, S.; Affek, H. P.; Tryon, C.; Peppe, D. J.; Faith, J.

2013-12-01

19

Effects of natal departure and water level on survival of juvenile snail kites (Rostrhamus sociabilis) in Florida  

USGS Publications Warehouse

Survival rate from fledging to breeding, or juvenile survival, is an important source of variation in lifetime reproductive success in birds. Therefore, determining the relationship between juvenile survival and environmental factors is essential to understanding fitness consequences of reproduction in many populations. With increases in density of individuals and depletion of food resources, quality of most habitats deteriorates during the breeding season. Individuals respond by dispersing in search of food resources. Therefore, to understand the influence of environmental factors on juvenile survival, it is also necessary to know how natal dispersal influences survival of juveniles. We examined effects of various environmental factors and natal dispersal behavior on juvenile survival of endangered Snail Kites (Rostrhamus sociabilis) in central and southern Florida, using a generalized estimating equations (GEEs) approach and model selection criteria. Our results suggested yearly effects and an influence of age and monthly minimum hydrologic levels on juvenile Snail Kite survival. Yearly variation in juvenile survival has been reported by other studies, and other reproductive components of Snail Kites also exhibit such variation. Age differences in juvenile survival have also been seen in other species during the juvenile period. Our results demonstrate a positive relationship between water levels and juvenile survival. We suggest that this is not a direct linear relationship, such that higher water means higher juvenile survival. The juvenile period is concurrent with onset of the wet season in the ecosystem we studied, and rainfall increases as juveniles age. For management purposes, we believe that inferences suggesting increasing water levels during the fledging period will increase juvenile survival may have short-term benefits but lead to long-term declines in prey abundance and possibly wetland vegetation structure.

Dreitz, V. J.; Kitchens, W. M.; DeAngelis, D. L.

2004-01-01

20

The Effect of Simulating Different Intermediate Host Snail Species on the Link between Water Temperature and Schistosomiasis Risk  

PubMed Central

Introduction A number of studies have attempted to predict the effects of climate change on schistosomiasis risk. The importance of considering different species of intermediate host snails separately has never previously been explored. Methods An agent-based model of water temperature and Biomphalaria pfeifferi population dynamics and Schistosoma mansoni transmission was parameterised to two additional species of snail: B. glabrata and B. alexandrina. Results Simulated B. alexandrina populations had lower minimum and maximum temperatures for survival than B. pfeifferi populations (12.5–29.5°C vs. 14.0–31.5°C). B. glabrata populations survived over a smaller range of temperatures than either B. pfeifferi or B. alexandrina (17.0°C–29.5°C). Infection risk peaked at 16.5°C, 25.0°C and 19.0°C respectively when B. pfeifferi, B. glabrata and B. alexandrina were simulated. For all species, infection risk increased sharply once a minimum temperature was reached. Conclusions The results from all three species suggest that infection risk may increase dramatically with small increases in temperature in areas at or near the currents limits of schistosome transmission. The effect of small increases in temperature in areas where schistosomiasis is currently found will depend both on current temperatures and on the species of snail acting as intermediate host(s) in the area. In most areas where B. pfeifferi is the host, infection risk is likely to decrease. In cooler areas where B. glabrata is the host, infection risk may increase slightly. In cooler areas where B. alexandrina is the host, infection risk may more than double with only 2°C increase in temperature. Our results show that it is crucial to consider the species of intermediate host when attempting to predict the effects of climate change on schistosomiasis.

McCreesh, Nicky; Booth, Mark

2014-01-01

21

Water near intracellular surfaces  

PubMed Central

In this paper we make the following points: Water is perturbed within several angstroms of the surfaces of soluble molecules. Removal of this water can require significant amounts of work, seen as an exponentially varying "hydration force" with respect to molecular separation. The favorable and specific attractions that occur in molecular assembly or in ligand binding imply that the specific association between the molecular surfaces is stronger than the association of those surfaces with water. The specificity of biochemical association is not simply a matter of protein-protein interaction but also of competing protein-water interactions. Small structural changes in molecular surfaces can evoke large changes in the contact energy of hydrated surfaces; surface hydration and the energetics of water displacement are a likely mechanism for the contact specificity of intracellular associations integrating the cell matrix.

Parsegian, V. A.; Rau, D. C.

1984-01-01

22

Surface water hydrology  

Microsoft Academic Search

Surface Water Hydrology is published by the Geological Society of America as Volume O-1 of its The Geology of North America series. The hardbound treatise is edited by M. G. Wolman and H. C. Riggs and is written as a companion to Hydrogeology (Volume O-2 of the same series). The thirteen chapters describe the occurrence and movement of water on

M. G. Wolman; H. C. Riggs

1990-01-01

23

Recovery of Pasteurella multocida from experimentally-exposed freshwater snails.  

PubMed

We determined how long Pasteurella multocida could survive in experimentally-exposed freshwater snails. Physa virginea were collected from the Sacramento National Wildlife Refuge, Glenn County, California (USA), an enzootic site for avian cholera. Exposure to water containing up to 10(7) P. multocida per ml did not produce observable changes or mortality in snails. A minimum of 84 P. multocida per snail was necessary for detection among the normal snail bacterial flora. When snails were exposed to P. multocida in vials containing 10(7) bacteria per ml, P. multocida was detected for up to 72 hours in snails. When uninoculated snails were placed in aquaria containing 10(6) P. multocida per ml, P. multocida was not detected within the snails; further, P. multocida was detected in the water for only 24 hours at this level. Based on these results, we propose that P. virginea is not an effective reservoir for P. multocida. PMID:8592357

Miller, S L; Botzler, R G

1995-07-01

24

Influence of an extreme high water event on survival, reproduction, and distribution of snail kites in Florida, USA  

USGS Publications Warehouse

Hydrology frequently has been reported as the environmental variable having the greatest influence on Florida snail kite (Rostrhamus sociabilis) populations. Although drought has received the most attention, high-water conditions also have been reported to affect kites. Years of high water generally have been reported to be favorable for nesting, although prolonged high water may be detrimental to sustaining suitable habitat. During 1994 and 1995, southern Florida experienced an extreme high water event. This event enabled us to compare survival, nesting success, number of young per successful nest, and spatial distribution of nesting before, during, and after the event. We found no evidence of an effect (either negative or positive) on survival of adult kites. In contrast, juvenile kites experienced the highest survival during the event, although our data suggest greater annual variability than can be explained by the event alone. We found no evidence of an effect of the high water event on nest success or number of young per successful nest. Nest success was highest during the event in the southern portion of the range but was quite similar to other years, both before and after the event. Our data do indicate a substantial shift in the spatial distribution of nesting birds. During the event, nesting activity shifted to higher elevations (i.e., shallower water) in the major nesting areas of the Everglades region. Nesting also occurred in Big Cypress National Preserve during the event, which is typically too dry to support nesting kites. Thus, our data indicate a potential short-term benefit of increased juvenile survival and an expansion of nesting habitat. However, the deterioration of habitat quality from prolonged high water precludes any recommendation for such conditions to be maintained for extended periods. ?? 2002, The Society of Wetland Scientists.

Bennetts, R. E.; Kitchens, W. M.; Dreitz, V. J.

2002-01-01

25

EPR theoretical study of local lattice structure on Mn 2+ ion doped in calcite and differences between single crystal and fresh water snail, Pila globosa  

Microsoft Academic Search

By diagonalizing the complete energy matrices for a d5 configuration ion in a trigonal ligand-field and considering the second-order, fourth-order EPR parameters D and (a?F) simultaneously, the substitution position of Mn2+ ion in the CaCO3:Mn2+ system has been studied by analyzing the optical absorption and EPR spectra of single crystal and the ostracum layer of operculum of fresh water snail

Cheng-Guo Fu; Xiao-Yu Kuang; Hui Wang; Xiong Yang; Xiao-Ming Tan

2006-01-01

26

Influence of Age and Body Size on Alarm Responses in a Freshwater Snail Pomacea canaliculata  

Microsoft Academic Search

A hypothesis that size selection of prey by predators elicits size-specific responses from prey was examined. Freshwater snails, Pomacea canaliculata, ages 1, 3, 7, 15, 30, or 60 days, were given an extract of 3-day-old snails, and 3-day-old snails were given extracts of snails of the other ages or eggs. Snails 15 days or younger crawled out of the water

Katsuya Ichinose

2002-01-01

27

Apple Snails (Ampullariidae)  

NSDL National Science Digital Library

This web site provides information on apple snails (family Ampullariidae), the largest living freshwater snails on earth, often kept as aquarium pets because of their attractive appearance and size. Topics include the care of apple snails, their anatomy, species and genera, and information on snail pests, embryology, and genetics. There is also a frequently-asked-questions feature, photos, links to web sites and literature, and an online discussion forum.

Ghesquiere, Stijn A.

28

Internal Surface Water Flows  

USGS Publications Warehouse

Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making.The U.S. Geological Survey (USGS) provides scientitic information as part of the South Florida Ecosystem Restoration Program. The USGS began its own project, called the South Florida Ecosystem Project in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Historical changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system with canals, levees, and pumping stations. These structures have altered the hydology of the Everglades ecosystem on both coastal and interior lands. Surface-water flows in a direction south of Lake Okeechobee have been regulated by an extensive canal network, begun in the 1940's, to provide for drainage, flood control, saltwater intrusion control, agricultural requirements, and various environmental needs. Much of the development and subsequent monitoring of canal and river discharge south of Lake Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has been placed on providing a more accurate water budget for internal canal flows.

Murray, Mitchell H.

1999-01-01

29

Is the interspecific variation of body size of land snails correlated with rainfall in Israel and Palestine?  

NASA Astrophysics Data System (ADS)

The hypothesis that body size of land snail species increases with aridity in Israel and Palestine because large snails lose relatively less water due to their lower surface to volume ratio has been investigated. Data on rainfall amplitudes of 84 land snail species in Israel and Palestine and on their body sizes were used to test for interspecific correlations between body size and rainfall. Four methods, means of body sizes in rainfall categories, the midpoint method, the across-species method, and a phylogenetically controlled analysis (CAIC) showed that there is no significant correlation between body size of land snail species and their rainfall amplitude in Israel and Palestine. The lack of an interspecific correlation between body size and rainfall amplitude may be the result of conflicting selective forces on body size.

Hausdorf, Bernhard

2006-11-01

30

Bioaccumulation of heavy metals in water, sediments, aquatic plant and histopathological effects on the golden apple snail in Beung Boraphet reservoir, Thailand.  

PubMed

Changes in the seasonal concentrations of heavy metals (Cu, Mn, Fe, Zn, Pb and Cd) were determined in water, sediments, snails (Pomacea canaliculata) and aquatic plants (Ipomoea aquatica) in three selected tributaries of the Beung Boraphet reservoir, Nakhon Sawan Province, central Thailand. Only Fe, Cu, Mn and Zn were detected by FAAS in all samples collected. The water quality of Beung Boraphet was medium clean with Fe, Mn, Cu and Zn concentrations well below internationally accepted limits. According to the criteria proposed for sediments by the EPA Region V, Zn and Mn concentrations were within the non-polluted range while Fe and Cu (wet season) concentrations fell into the class of severely polluted sediment. Both P. canaliculata and I. aquatica bioconcentrated more Mn in their tissues than were found in sediments, especially in the wet season. The results of Pearson correlation study and BCF values also indicated similar findings. Only Mn showed the importance of sediment-to-snail concentration and high BCF values in both snails and plants. P. canaliculata exposed to contaminated sediment for two months, showed higher accumulation of metals (Fe, Mn, Cu and Zn) in the digestive tracts and digestive glands than in the foot muscles. Histopathological changes included alterations in the epithelial lining of the digestive tracts, digestive glands and the gills. Loss of cilia and increase in mucous cells were observed in the digestive tracts and gills, while the digestive glands exhibited an increase of dark granules and basophilic cells, and dilation of digestive cells. The results indicated that both P. canaliculata and I. aquatica could be used as biomonitors of sedimentary metal contamination for the Beung Boraphet reservoir. PMID:23079739

Dummee, Vipawee; Kruatrachue, Maleeya; Trinachartvanit, Wachareeporn; Tanhan, Phanwimol; Pokethitiyook, Prayad; Damrongphol, Praneet

2012-12-01

31

Snails and trematode infection after Indian Ocean tsunami in Phang-Nga Province, southern Thailand.  

PubMed

The tsunami and non-tsunami affected areas of Takua Pa District, Phang-Nga Province were investigated for fresh- and brackish-water snails that transmit human parasitic diseases during 2006 and 2007. Among 46 snail species found, 17 species of 8 families were freshwater snails, 28 species of another 7 families were brackish-water snails, and 1 species was a land snail. Of these species, 11 freshwater snails, 4 brackish-water snails and 1 land snail were of medical importance. The fresh-water snails were Pomacea canaliculata, Pila angelica, P. gracilis, P. polita, Filopaludina (S.) martensi, F. (F.) s. polygramma, Melanoides tuberculata, Indoplanorbis exuxtus, Radix rubiginosa, Helicorbis umbilicalis, Gyraulus convexiusculus. Four brackish-water snails were Cerithidea cingulata, C. djadjarensis, C. alata, Sermyla riqueti and Achatina fulica was the land snail. I. exutus, M. tuberculata and F. (F.) s. polygramma harbored Xiphidio, Microcercus, Furocercus, Echinostome cercariae, and cercaria without eyespots or tail with hair. Three species of brackish-water snails, Cerithidia cingulata, C. djadjariensis, and C. alata presented with 6 types of trematode cercariae and rediae. Knowledge of medically important snails and their parasitic diseases, and prevention were given to Takua Pa people by poster, pamphlets and broadcasting through community radio. PMID:20578482

Sri-Aroon, Pusadee; Chusongsang, Phiraphol; Chusongsang, Yupa; Pornpimol, Surinthwong; Butraporn, Piyarat; Lohachit, Chantima

2010-01-01

32

Cercarial Dermatitis Transmitted by Exotic Marine Snail  

PubMed Central

Cercarial dermatitis (swimmer’s itch) is caused by the penetration of human skin by cercariae of schistosome parasites that develop in and are released from snail hosts. Cercarial dermatitis is frequently acquired in freshwater habitats, and less commonly in marine or estuarine waters. To investigate reports of a dermatitis outbreak in San Francisco Bay, California, we surveyed local snails for schistosome infections during 2005–2008. We found schistosomes only in Haminoea japonica, an Asian snail first reported in San Francisco Bay in 1999. Genetic markers place this schistosome within a large clade of avian schistosomes, but do not match any species for which there are genetic data. It is the second known schistosome species to cause dermatitis in western North American coastal waters; these species are transmitted by exotic snails. Introduction of exotic hosts can support unexpected emergence of an unknown parasite with serious medical or veterinary implications.

Cohen, Andrew N.; James, David; Hui, Lucia; Hom, Albert; Loker, Eric S.

2010-01-01

33

Water management on semiconductor surfaces  

Microsoft Academic Search

The wafer direct bonding technique is very sensitive to water adsorbed on surfaces just before bonding; hence it is a useful way to characterize the impact of the trapped water and subsequently the wafer drying efficiency. We have focused this work on the water behavior at the bonding interface depending on the nature of the surface but also depending on

Y. Le Tiec; C. Ventosa; N. Rochat; F. Fournel; H. Moriceau; L. Clavelier; F. Rieutord; J. Butterbaugh; I. Radu

34

Toxic Effects of Cadmium on Reproduction, Development, and Hatching in the Freshwater Snail Lymnaea stagnalisfor Water Quality Monitoring  

Microsoft Academic Search

The freshwater snailLymnaea stagnaliswas exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 ?g liter?1. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 ?g Cd2+liter?1and hatching was reduced to 0.4% with 200 ?g liter?1at 20°C.

Annette Gomot

1998-01-01

35

SURFACE WATER INTAKES  

EPA Science Inventory

The Safe Drinking Water Information System (SDWIS) GIS layer represents the locations of public water system (PWS) facilities in NY and NJ; every PWS has one or more facilities. Data for this layer came from the Safe Drinking Water Information System/Federal version (SDWIS/FED)...

36

Measuring Surface Water From Space  

NASA Astrophysics Data System (ADS)

Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface fresh water discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?" Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in-situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface (h), its slope (dh/dx), and temporal change (dh/dt). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge, but are successful only when in-situ data are available for calibration and fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multi-decadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing fresh water bodies. However, altimeters are profiling tools which, because of their orbital spacings, miss too many fresh water bodies to be useful hydrologically. High spatial resolution images of dh/dt have been observed with interferometric synthetic aperture radar (SAR), but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model the water cycle and to guide water management practices. Instead, a combined imaging and elevation measuring approach is ideal as demonstrated by the Shuttle Radar Topography Mission (SRTM), which collected images of h at a high spatial resolution (~90m, thus permitting the calculation of dh/dx). We suggest that a future satellite concept, the Water And Terrestrial Elevation Recovery mission (WATER), will improve upon the SRTM design to permit multi-temporal mappings of h across the world's wetlands, floodplains, lakes, reservoirs, and rivers. state.edu/water/

Partsch, J.; Alsdorf, D.; Rodriguez, E.; Lettenmaier, D.; Mognard, N.; Participants, T.

2006-12-01

37

EPR theoretical study of local lattice structure on Mn 2+ ion doped in calcite and differences between single crystal and fresh water snail, Pila globosa  

NASA Astrophysics Data System (ADS)

By diagonalizing the complete energy matrices for a d5 configuration ion in a trigonal ligand-field and considering the second-order, fourth-order EPR parameters D and ( a - F) simultaneously, the substitution position of Mn 2+ ion in the CaCO 3:Mn 2+ system has been studied by analyzing the optical absorption and EPR spectra of single crystal and the ostracum layer of operculum of fresh water snail Pila globosa. The results show that in the single crystal there is an obvious compressed distortion ? R = -0.158 Å and ? ? = 0.70°, and the distortion in P. globosa is ? R = -0.107 Å and ? ? = -0.34° ˜ -0.23°. Meanwhile the EPR parameters 10 4( a - F) = 7.02-7.29 cm -1 and 10 4a = 6.35 cm -1 are predicted in P. globosa.

Fu, Cheng-Guo; Kuang, Xiao-Yu; Wang, Hui; Yang, Xiong; Tan, Xiao-Ming

2006-06-01

38

RoboSnail  

NSDL National Science Digital Library

In this video segment adapted from the Massachusetts Institute of Technology, a team from the Mechanical Engineering Department studies snail movement for inspiration that may lead to new forms of robotic locomotion.

Foundation, Wgbh E.

2006-05-09

39

Groundwater and surface water pollution  

SciTech Connect

This book contains almost all the technical know-how that is required to clean up the water supply. It provides a survey of up-to-date technologies for remediation, as well as a step-by-step guide to pollution assessment for both ground and surface waters. In addition to focusing on causes, effects, and remedies, the book stresses reuse, recycling, and recovery of resources. The authors suggest that through total recycling wastes can become resources.

Chae, Y.S.; Hamidi, A. [eds.

2000-07-01

40

Groundwater and surface water pollution  

Microsoft Academic Search

This book contains almost all the technical know-how that is required to clean up the water supply. It provides a survey of up-to-date technologies for remediation, as well as a step-by-step guide to pollution assessment for both ground and surface waters. In addition to focusing on causes, effects, and remedies, the book stresses reuse, recycling, and recovery of resources. The

Y. S. Chae; A. Hamidi

2000-01-01

41

Relationship between Snail Population Density and Infection Status of Snails and Fish with Zoonotic Trematodes in Vietnamese Carp Nurseries  

PubMed Central

Background Fish-borne zoonotic trematodes (FZT) are a food safety and health concern in Vietnam. Humans and other final hosts acquire these parasites from eating raw or under-cooked fish with FZT metacercariae. Fish raised in ponds are exposed to cercariae shed by snail hosts that are common in fish farm ponds. Previous risk assessment on FZT transmission in the Red River Delta of Vietnam identified carp nursery ponds as major sites of transmission. In this study, we analyzed the association between snail population density and heterophyid trematode infection in snails with the rate of FZT transmission to juvenile fish raised in carp nurseries. Methodology/Principal Findings Snail population density and prevalence of trematode (Heterophyidae) infections were determined in 48 carp nurseries producing Rohu juveniles, (Labeo rohita) in the Red River Delta area. Fish samples were examined at 3, 6 and 9 weeks after the juvenile fish were introduced into the ponds. There was a significant positive correlation between prevalence of FZT metacercariae in juvenile fish and density of infected snails. Thus, the odds of infection in juvenile fish were 4.36 and 11.32 times higher for ponds with medium and high density of snails, respectively, compared to ponds where no infected snails were found. Further, the intensity of fish FZT infections increased with the density of infected snails. Interestingly, however, some ponds with no or few infected snails were collected also had high prevalence and intensity of FZT in juvenile fish. This may be due to immigration of cercariae into the pond from external water sources. Conclusions/Significance The total number and density of potential host snails and density of host snails infected with heterophyid trematodes in the aquaculture pond is a useful predictor for infections in juvenile fish, although infection levels in juvenile fish can occur despite low density or absence infected snails. This suggests that intervention programs to control FZT infection of fish should include not only intra-pond snail control, but also include water sources of allochthonous cercariae, i.e. canals supplying water to ponds as well as snail habitats outside the pond such as rice fields and surrounding ponds.

Clausen, Jesper Hedegaard; Madsen, Henry; Murrell, K. Darwin; Phan Thi, Van; Nguyen Manh, Hung; Viet, Khue Nguyen; Dalsgaard, Anders

2012-01-01

42

Ground and Surface Water Concepts  

NSDL National Science Digital Library

This section of the Digital Atlas of Idaho contains an extensive collection of information about hydrology. Topics include surface water/groundwater interaction, runoff, stream gauging, hydrographs, aquifer types, groundwater movement, aquifer response to pumping, and more. The information is suitable for an upper level college audience.

Welhan, John; Mcnamara, Jim; Project, The D.

43

Small Snails, Enormous Elephants  

NSDL National Science Digital Library

This activity (located on page 2 of PDF) introduces learners to the real size of animals using nonstandard measurement. Learners use Unifix cubes and yarn lengths to measure a variety of animals (photos), from the very small like a snail to the very large like an elephant. As an extension, learners can use the cubes to create a bar graph depicting the animals' lengths.

Museum, Chicago C.

2011-01-01

44

The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail  

PubMed Central

Most of the shell material in snails is composed of calcium carbonate but the organic shell matrix determines the properties of calcium carbonate crystals. It has been shown that the deposition of calcium carbonate is affected by the ingestion of organic compounds. We hypothesize that organic compounds not synthesized by the snails are important for shell strength and must be obtained from the diet. We tested this idea indirectly by evaluating whether the abundance of the organic matter that snails eat is related to the strength of their shells. We measured shell crushing resistance in the snail Mexipyrgus churinceanus and the abundance of the most common aquatic macrophyte, the water lily Nymphaea ampla, in ten bodies of water in the valley of Cuatro Ciénegas, Mexico. We used stable isotopes to test the assumption that these snails feed on water lily organic matter. We also measured other factors that can affect crushing resistance, such as the density of crushing predators, snail density, water pH, and the concentration of calcium and phosphorus in the water. The isotope analysis suggested that snails assimilate water lily organic matter that is metabolized by sediment bacteria. The variable that best explained the variation in crushing resistance found among sites was the local abundance of water lilies. We propose that the local amount of water lily organic matter provides organic compounds important in shell biomineralization, thus determining crushing resistance. Hence, we propose that a third trophic level could be important in the coevolution of snail defensive traits and predatory structures.

Chaves-Campos, Johel; Coghill, Lyndon M.; Garcia de Leon, Francisco J.; Johnson, Steven G.

2012-01-01

45

Heavy metal concentrations in the freshwater snail Biomphalaria alexandrina uninfected or infected with cercariae of Schistosoma mansoni and/or Echinostoma liei in Egypt: the potential use of this snail as a bioindicator of pollution.  

PubMed

In spite of using aquatic snails as bioindicators for water pollution, little attention has been paid to the effect of parasitism upon the concentration of heavy metals (Al, Cd, Cu, Fe, Mn, Pb and Zn) in these organisms. The present study therefore aimed to compare the concentrations of heavy metals in trematode-infected Biomphalaria alexandrina collected from Kafer Alsheikh and Menofia provinces, Egypt, with uninfected snails from the same sites, in order to assess the effect of parasitism on the use of these snails as bioindicators. The concentrations of heavy metals in the soft parts and shells of snails were measured by flame atomic absorption spectrometry. The results showed that the heavy metal profile in snails infected with Echinostoma liei was very different from that in snails infected with Schistosoma mansoni. The total concentration of heavy metals in E. liei-infected snails collected from Kafer Alsheikh or Menofia province was greater than in uninfected snails. In contrast, the total concentration of heavy metals in S. mansoni-infected snails was reduced compared with uninfected snails. In conclusion, the status of snails with respect to parasitic infection must be taken into consideration when these snails are used as bioindicators. PMID:23710821

Mostafa, O M S; Mossa, A-T H; El Einin, H M A

2013-05-28

46

Studies on Lymnaea snails and their trematode parasites in Abis II village, Alexandria.  

PubMed

Lymnaea snails in Abis II village were studied as regard their species, monthly distribution, density and infection rates in different water bodies. The trematode parasites in L. cailliaudi, the only species of Lymnaea in Abis II village were xiphidio in 40% of snails and Fasciola in 10%. Echinostome cercariae were detected from few snails outside Abis II village. The morphological characters of the different larval stages of the detected parasites were described. PMID:8376865

Salem, A I; Osman, M M; el-Daly, S; Farahat, A

1993-08-01

47

Baldomero Olivera: Cone Snail Peptides  

NSDL National Science Digital Library

Have you ever considered the venom of a snail? Most people think of snakes when they think of venom but overlook snails. There are, however, almost 10,000 species of venomous predatory snails according to this engaging lecture from Professor Baldomero Olivera. In his talk, Professor Olivera explores how these venoms have been used to understand the nervous system and develop new drugs. The lecture is divided into three different sections, and visitors shouldn't miss Part 2 ("How a Fish Hunting Snail Captures Its Prey"). Visitors are also welcome to download the entire lecture and the accompanying slides.

Olivera, Baldomero

48

Baldomero Olivera: Cone Snail Peptides  

NSDL National Science Digital Library

Have you ever considered the venom of a snail? Most people think of snakes when they think of venom but overlook snails. There are, however, almost 10,000 species of venomous predatory snails according to this engaging lecture from Professor Baldomero Olivera. In his talk, Professor Olivera explores how these venoms have been used to understand the nervous system and develop new drugs. The lecture is divided into three different sections, and visitors shouldn't miss Part 2 ("How a Fish Hunting Snail Captures Its Prey"). Visitors are also welcome to download the entire lecture and the accompanying slides.

Olivera, Baldomero

2012-01-31

49

Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba.  

PubMed

The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA) whereas the resistant population inhabited the most preserved one (El Azufre). Only two snail species coexisted with P. columella at IPA site (Physa cubensis and Tarebia granifera) while five species were found at El Azufre, including an endemic from that province (Hemisinus cubanianus). Populations of both resistant and susceptible snails showed stable densities throughout the year, although the susceptible strain attained higher abundance. The highest densities were observed in April-May 2004 for the susceptible population whereas the resistant strain attained its highest abundance in January 2004. No record of Fossaria cubensis was made and the thiarid T. granifera occurred only at low densities. One of the sampled sites (IPA) meets all the conditions for the first report of P. columella naturally infected with larvae of F. hepatica. PMID:16410958

Gutiérrez, Alfredo; Hernandez, Dagmar F; Sánchez, Jorge

2005-11-01

50

Effects of Schistosoma mansoni experimental infection on some inorganic elements in the snail host Biomphalaria alexandrina.  

PubMed

The alteration in the concentrations of metallic ion Pb, Zn, K, Na, Co, Fe, and Cu in the soft parts of the Biomphalaria alexandrina snails shedding Schistosoma mansoni cercariae was detected by flame atomic absorption spectrometry. Six elements Pb, Zn, K, Na, Co, and Cu were found to be present at significantly higher concentrations in cercariae-shedding snails compared with uninfected snails. The concentration of Fe ion showed non-significant decrease in the tissues of cercariae-shedding snails. Variation in the present results compared with related previous studies lead to the suggestion that the effect of trematode parasitism on fresh-water snails should not be considered universal and might be varies according to the trematode-snail combination, the organs or the tissues analyzed and the analytical method used. PMID:20503598

Mostafa, Osama M S; Dajem, Saad M Bin

2010-04-01

51

Polymorphism in pleistocene land snails.  

PubMed

Under suitable conditions the colors and patterns of the shells of land snails may be preserved for thousands of years. In a late Pleistocene population of Limicolaria martensiana all the major color forms that occur in modern living snails may be distinguished, and the basic polymorphism is at least 8,000 to 10,000 year old. PMID:17830234

Owen, D F

1966-04-01

52

Surface water discharges from onshore stripper wells.  

National Technical Information Service (NTIS)

Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from dischargin...

J. A. Veil

1998-01-01

53

TREATMENT OF SEASONAL PESTICIDES IN SURFACE WATERS  

EPA Science Inventory

Numerous pesticides were monitored in surface waters in agricultural areas. Atrazine, alachlor, metolachlor, cyanazine, metribuzin, carbofuran, linuron, and simazine were found in the influent to three water treatment plants in storm runoff following their application. Studies at...

54

USGS Surface Water Information: Flood Information  

NSDL National Science Digital Library

This site from the USGS Office of Surface Water provides access to many resources and data sets about current and past flooding events in the United States. There are links to maps showing current water conditions, 28 day National Weather Service forecasts, Water Science Centers in the various states, as well as national and local flooding resources. There are also links to other parts of the USGS Surface Water Information site which host a variety of data and information resources.

Water, Usgs O.

55

Sediment copper bioavailability to freshwater snails in south Florida: risk implications for the Everglade snail kite (Rostrhamus sociabilis plumbeus).  

PubMed

Many properties being acquired as part of the Comprehensive Everglades Restoration Plan (CERP) are heavily contaminated with copper. Estimated copper bioaccumulation in the Florida apple snail (Pomacea paludosa) has led to the prediction of risk to the Everglade snail kite (Rostrhamus sociabilis plumbeus) at some CERP projects. Field study results presented in this paper examine the relationship between copper levels in sediments, snails, and other biota. Copper concentrations in all biota (snails, aquatic vascular plants, and periphyton) were strongly correlated with those in sediments. No correlation with water copper concentrations was evident. Mean copper concentrations in snails ranged from 23.9 mg/kg at the reference site to 732 mg/kg at a high copper site. Calculated biota-sediment accumulation factors (BSAFs) ranged from 36.7 to 7.0 over the range of copper levels in sediments. BSAFs were highest at low copper levels in sediments and declined sharply as copper levels in sediment increased. Risk for the snail kite is discussed in light of the results of this study. PMID:18679796

Frakes, Robert A; Bargar, Timothy A; Bauer, Emily A

2008-10-01

56

Herbivory on aquatic vascular plants by the introduced golden apple snail ( Pomacea canaliculata ) in Lao PDR  

Microsoft Academic Search

The effect of naturally found densities of the exotic and herbivorous golden apple snail (Pomacea canaliculata) on three dominant aquatic plants – duckweed (Lemna minor), water hyacinth (Eichhornia crassipes) and morning glory (Ipomoea aquatica) – was assessed in a wetland survey and quantified in a field experiment in Laos in southeast Asia. Snail grazing reduced plant biomass, but plant species

Nils O. L. Carlsson; Jean O. Lacoursière

2005-01-01

57

Tests of the Ability of Five Disinfectants to Kill New Zealand Mud Snails  

Microsoft Academic Search

We exposed New Zealand mud snails (NZMS), Potamopyrgus antipodarum, to various concentrations of four different quaternary ammonium-based disinfectants (Roccal D-Plus, Hyamine 1622, benzalkonium chloride, and Stepanquat 50 NF) and to liquid dish soap (Dawn) for 15 min. After 24 h of recovery in water, survival of the exposed snails was determined. Generally, mortality increased with increased chemical concentration. A concentration

Randall W. Oplinger; Eric Wagner

2011-01-01

58

Interaction between water and defective silica surfaces  

SciTech Connect

We use the density functional theory method to study dry (1 x 1) {alpha}-quartz (0001) surfaces that have Frenkel-like defects such as oxygen vacancy and oxygen displacement. These defects have distinctively different effects on the water-silica interface depending on whether the adsorbent is a single water molecule, a cluster, or a thin film. The adsorption energies, bonding energies, and charge transfer or redistributions are analyzed, from which we find that the existence of a defect enhances the water molecule and cluster surface interaction by a large amount, but has little or even negative effect on water thin film-silica surface interaction. The origin of the weakening in film-surface systems is the collective hydrogen bonding that compromises the water-surface interaction in the process of optimizing the total energy. For clusters on surfaces, the lowest total energy states lower both the bonding energy and the adsorption energy.

Chen Yunwen; Cheng Haiping [Department of Physics and Quantum Theory Project, University of Florida, Gainesville, Florida 32611 (United States)

2011-03-21

59

Use of a saponin based molluscicide to control Pomacea canaliculata snails in Southern Brazil.  

PubMed

Pomacea canaliculata snails pose a severe problem to direct seeded rice cultivated in Southern Brazil. Control of this snail is nowadays performed with toxic chemicals such as copper sulfate and fungicides such as fentin. A novel natural molluscicide based on alkali modified quinoa (Chenopodium quinoa) saponins was tested under laboratory conditions. Snails were collected in rice fields close to Porto Alegre (State of Rio Grande do Sul) and in Brusque (State of Santa Catarina, 400 km north of Porto Alegre). In Santa Catarina the product was very effective, while in Porto Alegre it had no effect. This unexpected behavior was probably due to the respiratory habits of the snails under different contents of dissolved oxygen in the water. Near Porto Alegre the water used in rice fields is heavily polluted, with dissolved oxygen levels of 1-2 ppm, and the snails rely primarily on their siphon and lungs to breathe. Since saponin control is probably due to an interaction between saponins with the sterols present in the cell walls in the gills, no control was observed. By contrast, in Santa Catarina the dissolved oxygen level of the water is 5-6 ppm, and the snails remain mostly underwater, breathing with their gills. In this case the snails died within 24 h at a dose of 20 and 30 ppm of product. To test this observation, snails grown in polluted waters were forced to remain underwater in saponin solutions and water (control) preventing the use of their siphon to breathe. The snails exposed to saponin solutions died, while the control snails survived, indicating that they were still able to use their gills to breathe. These results indicate that the use of the saponin product is limited to rice fields not irrigated with heavily polluted waters. PMID:19911565

San Martíns, R; Gelmi, Claudio; de Oliveira, Jaime Vargas; Galo, José Luis; Pranto, Honorio

2009-10-01

60

Polarimetric thermal emission from periodic water surfaces  

Microsoft Academic Search

In this paper, experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate

S. H. Yueh; S. V. Nghiem; R. Kwok; W. J. Wilson; F. K. Li; J. T. Johnson; J. A. Kong

1994-01-01

61

Seneca Lake Meteorological and Surface Water Data.  

National Technical Information Service (NTIS)

The report presents meteorological and surface water data collected at Seneca Lake, N. Y. The meteorological data represent 33,899 data points collected from 1934 to 1968, and the surface water data represent 1,222 data points collected from 1967 to 1968....

T. R. Cummings

1969-01-01

62

Geochemistry of surface waters of Vojvodina, Yugoslavia  

NASA Astrophysics Data System (ADS)

Major elements data are presented for a number of surface water samples from the Vojvodina region of Yugoslavia. These include samples from the Danube and Tisa Rivers as well as from three lakes in the Pannonian Plain. The data indicate that surface waters evolved to two major water types: Na-CO 3-SO 4-Cl and Na-Cl. The chemical composition of the surface water from this region has been strongly affected by anthropogenic activities including irrigation and the direct introduction of various chemical species, especially Na and Cl. It appears that the major element chemistry of a number of lakes in this region has changed since the 1950s.

Berry Lyons, W.; Lent, Robert M.; Djukic, Nada; Maletin, Steven; Pujin, Vlasta; Carey, Anne E.

1992-08-01

63

Two dimensional mixtures at water surface  

NASA Astrophysics Data System (ADS)

Thiol capped gold nanoparticles (Au NPs) form a simple two dimensional (2D) liquid on water surface but this thin film is unstable under compression. Amphiphilic stearic acid (StA) molecules on water surface, on the other hand, form a complex and more stable 2D liquid. We have initiated a study on a mixture of StA and Au NPs in a monolayer through Surface Pressure (?) - Specific Molecular Area (A) isotherms and Brewster Angle Microscopy (BAM). A mixture of Stearic Acid and Au nanoparticles (10% by weight) produces a monolayer on water surface that acts as a 2D liquid with phases that are completely reversible with negligible hysteresis.

Choudhuri, Madhumita; Datta, Alokmay

2013-02-01

64

Supercooling ability is surprisingly invariable in eggs of the land snail Cantareus aspersus.  

PubMed

From an ontogenetic point of view, invertebrate eggs are generally the most freezing intolerant stage of a species. Development state, water content and acclimation may affect their supercooling ability. In this study, we measured fresh mass, water content and temperature of crystallisation (T(c)) of eggs of the edible land snail Cantareus aspersus, depending on its form ("aspersa"vs. "maxima"), incubation temperature (20, 12 and 7 degrees C) and physiological age (as part of the complete development). We also tested their tolerance to freezing. Despite a high number of individual observations (n=759) and significant differences of fresh mass and water content between both subspecies, no effect of origin, incubation temperature or development state has been found in this study. T(c) remained constant whatever the condition, with an overall mean of -5.40+/-0.24 degrees C (mean+/-SD). We suggest that fresh mass is important, a high water content and a constantly wet surface confer to land snail eggs a poor ability to supercool. Moreover, the presence of ice nucleating agents at the egg surface (microorganisms present in the soil, calcium carbonate crystals of the egg shell) might induce freezing. Thus, considering the present results, to delay hatching by cryopreservation of eggs does not seem possible. PMID:17189625

Ansart, Armelle; Madec, Luc; Vernon, Philippe

2007-02-01

65

Water vapor retrieval over many surface types  

SciTech Connect

In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

Borel, C.C.; Clodius, W.C.; Johnson, J.

1996-04-01

66

Gas Transfer at Water Surfaces  

NASA Astrophysics Data System (ADS)

The burning of fossil carbon compounds causes an annual rise of about 0.2% of the total atmospheric CO2, which is about 50% the annual output of manmade CO2. One of the major reasons for this beneficial phenomenon is probably the CO2 uptake by the ocean water. A thorough knowledge of this process is needed for a prediction of the long-term impact of the use of fossil fuels on the environment. The example indicates that mass transfer across the gas-water interface is an important aspect in the geophysical, geochemical, and biochemcial cycle of natural and manmade substances. It regulates the transition between the dissolved state in the water and the gaseous state in the atmosphere. The knowledge of the air-water exchange is probably the most advanced of all the transport processes between environmental compartments. Nevertheless, there is still a need for a better understanding of this interfacial mass transfer, which is a critical factor of great scientific and practical relevance in assessments of the various pathways of wastes in the environment and for their engineering management.

Matthess, Georg

1984-04-01

67

HEALTH ASPECTS OF SURFACE WATER SUPPLIES  

EPA Science Inventory

Current EPA regulations are insufficient to prevent the waterborne transmission of disease, as waterborne outbreaks have occurred in systems which have not exceeded current regulation for coliforms and turbidity. Waterborne outbreaks reported in surface water systems provide data...

68

Surface processing using water cluster ion beams  

NASA Astrophysics Data System (ADS)

Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

2013-07-01

69

The Occurrence of Glyphosate in Surface Water  

Microsoft Academic Search

The commonly used non-selective herbicide glyphosate (N-[Phosphonomethyl]glycin) occurred in surface water of two small tributaries of the river Ruhr in North-Rhine-Westphalia (FRG) with a maximum concentration of 590 ng\\/l. In the examined catchment areas weed control application in rail tracks is one of the main sources of an input to surface water. The occurrence of the metabolite aminomethyl phosphonic acid

Christian Skark; Ninette Zullei-seibert; Uwe Schöttler; Claus Schlett

1998-01-01

70

The Bethe surface of liquid water.  

SciTech Connect

The Bethe surface of liquid water, earlier calculated using a semi-empirical model, is compared with recent available data from IXS-experiments (inelastic X-ray scattering; Compton scattering of high energy photons) in liquid water. No alarming discrepancy is found on a global view of the Bethe surface. The extrapolation to the optical limit (viz., at zero momentum transfer) is shown and the reliability of these data is discussed in detail.

Dingfelder, M.

1998-10-14

71

Electrohydrodynamics of water droplets on polymer surfaces  

Microsoft Academic Search

For a complete comprehension of the phenomena connected with the flashover of polymeric insulators, we must first understand the behavior of sessile water droplets in strong electric fields existing on hydrophobic surfaces. The purpose of this paper is to study the distortion of water droplets under electric stress, which causes electric field enhancement, which is the key phenomenon behind the

R. Sundararajan; S. Sundhur; T. Asokan

1999-01-01

72

Microwave Scattering From an Agitated Water Surface.  

National Technical Information Service (NTIS)

An investigation was conducted into the detection of low frequency sound waves by the reflection of 8 mm microwaves from the water surface. For acoustic waves of moderate intensity, the ratio of amplitude of water motion to the wavelength of 8 mm microwav...

H. S. Hutchins D. J. Angelakos

1968-01-01

73

How Water Meets a Very Hydrophobic Surface  

NASA Astrophysics Data System (ADS)

Is there a low-density region (“gap”) between water and a hydrophobic surface? Previous x-ray and neutron reflectivity results have been inconsistent because the effect (if any) is subresolution for the surfaces studied. We have used x-ray reflectivity to probe the interface between water and more hydrophobic smooth surfaces. The depleted region width increases with contact angle and becomes larger than the resolution, allowing definitive measurements. Large fluctuations are predicted at this interface; however, we find that their contribution to the interface roughness is too small to measure.

Chattopadhyay, Sudeshna; Uysal, Ahmet; Stripe, Benjamin; Ha, Young-Geun; Marks, Tobin J.; Karapetrova, Evguenia A.; Dutta, Pulak

2010-07-01

74

Polarimetric thermal emission from periodic water surfaces  

NASA Technical Reports Server (NTRS)

Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

1993-01-01

75

Water surface locomotion in tropical canopy ants.  

PubMed

Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. PMID:24920838

Yanoviak, S P; Frederick, D N

2014-06-15

76

Coupled surface-water and ground-water model  

USGS Publications Warehouse

In areas with dynamic and hydraulically well connected ground-water and surface-water systems, it is desirable that stream-aquifer interaction be simulated with models of equal sophistication and accuracy. Accordingly, a new, coupled ground-water and surface-water model was developed by combining the U.S. Geological Survey models MODFLOW and BRANCH. MODFLOW is the widely used modular three-dimensional, finite-difference, ground-water model and BRANCH is a one-dimensional numerical model commonly used to simulate flow in open-channel networks. Because time steps used in ground-water modeling commonly are much longer than those used in surface-water simulations, provision has been made for handling multiple BRANCH time steps within one MODFLOW time step. Verification testing of the coupled model was done using data from previous studies and by comparing results with output from a simpler four-point implicit open-channel flow model linked with MODFLOW.

Swain, Eric, D.; Wexler, Eliezer, J.

1991-01-01

77

Water dynamics near solutes and surfaces  

NASA Astrophysics Data System (ADS)

The hydrogen bonding structure and dynamics of water are fundamentally important in a wide range of chemical, biological, geological, and industrial systems. Infrared spectroscopy of the OD stretch of dilute HOD in H2 O provides a sensitive probe of the hydrogen bonding network of water. Water forms a nominally tetrahedral hydrogen bonding network as a liquid but rapid hydrogen bond switching events lead to fast water reorientation. A mechanism for water reorientation that involves large amplitude angular jumps has recently been proposed to describe the long time orientational dynamics. At short times, water molecules quickly sample a restricted range of angular space within an intact hydrogen bonding configuration. The amplitude of this inertial reorientation depends on the strength of the local hydrogen bonding network. When hydrogen bonds are stronger, the water is restricted to a smaller angular range about the hydrogen bond axis. Weaker hydrogen bonds allow larger angular excursions. A simple model for the angular hydrogen bond potential energy surface is presented based on the experimental data. Water is rarely found as a pure liquid in real systems. Often it is in contact with a surface and its dynamics are modified near the surface. Reverse micelles formed using the surfactant Aerosol-OT (AOT), water, and isooctane, as well as AOT lamellar structures provide well-defined, tunable model systems to study the dynamics of water interacting with an interface. Reverse micelles are spherical water pools with radii that can be varied from less than one nanometer up to tens of nanometers. Lamellar structures are surfactant bilayers separated by thin sheets of water ranging in thickness from approximately one nanometer up to four nanometers. In large reverse micelles and lamellar structures, the confined water can be separated into two components, a core of bulk-like water and a shell of interfacial water. Polarization selective pump-probe spectroscopy of the OD stretch of dilute HOD in H2O confined in the reverse micelles provides a probe of the dynamics of the confined water. The characteristic vibrational lifetime and orientational correlation time of interfacial water are determined from a detailed investigation of the frequency dependence of the vibrational population relaxation and orientational anisotropy. The properties of interfacial water are independent of size and geometry for large reverse micelles and lamellar structures, indicating that it is the presence of an interface, not the geometry of the system or a specific confining length scale that affects the dynamics of interfacial water. As the reverse micelle size is decreased, the number of water molecules becomes small enough that the collective nature of water reorientation begins to cause the water away from the interface to be affected by the presence of the interface. One of the most fundamental water-solute interactions is the transport of ions by water. This process is governed by the exchange of water molecules in the solvation shell of the ion. Solvation shell exchange is studied using pump-probe and 2D-IR Chemical Exchange Spectroscopy of a mixture of water and sodium tetrafluoroborate (NaBF4). The timescale for solvation shell exchange is extracted by simultaneously fitting the chemical exchange data, the vibrational population relaxation and the orientational anisotropy data to a kinetic model. Anion solvation shell exchange occurs on a timescale of approximately seven picoseconds, allowing rapid ion transport in solution.

Moilanen, David Emil

78

Recovery from acidification in European surface waters  

Microsoft Academic Search

Water quality data for 56 long-term monitoring sites in eight European countries are used to assess freshwater responses to reductions in acid deposition at a large spatial scale. In a consistent analysis of trends from 1980 onwards, the majority of surface waters (38 of 56) showed significant (p <=0.05) decreasing trends in pollution-derived sulphate. Only two sites showed a significant

C. D. Evans; J. M. Cullen; C. Alewell; J. Kopácek; A. Marchetto; F. Moldan; A. Prechtel; M. Rogora; J. Veselý; R. Wright

2001-01-01

79

Effects of Endocrine Disruptors on Prosobranch Snails (Mollusca: Gastropoda) in the Laboratory. Part III: Cyproterone Acetate and Vinclozolin as Antiandrogens  

Microsoft Academic Search

The effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed in laboratory experiments. In this last of three publications, the responses of the fresh water snail Marisa cornuarietis and of two marine prosobranchs (Nucella lapillus, Nassarius (Hinia) reticulatus) to the antiandrogenic model compounds cyproterone acetate (CPA) and vinclozolin (VZ) are presented. The snails were exposed

Michaela Tillmann; Ulrike Schulte-Oehlmann; Martina Duft; Bernd Markert

2001-01-01

80

Pollution of surface water in Europe  

PubMed Central

This paper discusses pollution of surface water in 18 European countries. For each an account is given of its physical character, population, industries, and present condition of water supplies; the legal, administrative, and technical means of controlling pollution are then described, and an outline is given of current research on the difficulties peculiar to each country. A general discussion of various aspects common to the European problem of water pollution follows; standards of quality are suggested; some difficulties likely to arise in the near future are indicated, and international collaboration, primarily by the exchange of information, is recommended to check or forestall these trends.

Key, A.

1956-01-01

81

NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER  

EPA Science Inventory

The foulant from pilot nanofiltration membrane elements fed conventionally-treated surface water for 15 months was analyzed for organic, inorganic, and biological parameters. The foulant responsible for flux loss was shown to be a film layer 20 to 80 um thick with the greatest de...

82

Modeling copper partitioning in surface waters  

Microsoft Academic Search

Suspended particulate matter from the surface waters of the Susquehanna, Christina and Brandywine Rivers was collected by tangential flow filtration to study copper partitioning. Copper adsorption increased with an increase of suspended particles and decreased with low pH values or with an increase of dissolved organic matter. Effects of particulate organic matter on copper distribution between suspended particulate and solution

Bo Shi; Herbert E. Allen; Marco T. Grassi; Huizhong Ma

1998-01-01

83

Observing Global Surface Water Flood Dynamics  

NASA Astrophysics Data System (ADS)

Flood waves moving along river systems are both a key determinant of globally important biogeochemical and ecological processes and, at particular times and particular places, a major environmental hazard. In developed countries, sophisticated observing networks and ancillary data, such as channel bathymetry and floodplain terrain, exist with which to understand and model floods. However, at global scales, satellite data currently provide the only means of undertaking such studies. At present, there is no satellite mission dedicated to observing surface water dynamics and, therefore, surface water scientists make use of a range of sensors developed for other purposes that are distinctly sub-optimal for the task in hand. Nevertheless, by careful combination of the data available from topographic mapping, oceanographic, cryospheric and geodetic satellites, progress in understanding some of the world's major river, floodplain and wetland systems can be made. This paper reviews the surface water data sets available to hydrologists on a global scale and the recent progress made in the field. Further, the paper looks forward to the proposed NASA/CNES Surface Water Ocean Topography satellite mission that may for the first time provide an instrument that meets the needs of the hydrology community.

Bates, Paul D.; Neal, Jefferey C.; Alsdorf, Douglas; Schumann, Guy J.-P.

2014-05-01

84

Occurrence of Klebisiella pneumoniae in Surface Waters  

PubMed Central

The occurrence of Klebsiella pneumoniae in surface waters was not found to be ubiquitous. When it was isolated, Escherichia coli could also be found. The fecal coliform to fecal streptococci ratio suggest that its origin could be human animal, or mixed sources.

Knittel, M. D.

1975-01-01

85

Electrolysis of water on (oxidized) metal surfaces  

NASA Astrophysics Data System (ADS)

Density functional theory calculations are used as the basis for an analysis of the electrochemical process, where by water is split to form molecular oxygen and hydrogen. We develop a method for obtaining the thermochemistry of the electrochemical water splitting process as a function of the bias directly from the electronic structure calculations. We consider electrodes of Pt(1 1 1) and Au(1 1 1) in detail and then discuss trends for a series of different metals. We show that the difficult step in the water splitting process is the formation of superoxy-type (OOH) species on the surface by the splitting of a water molecule on top an adsorbed oxygen atom. One conclusion is that this is only possible on metal surfaces that are (partly) oxidized. We show that the binding energies of the different intermediates are linearly correlated for a number of metals. In a simple analysis, where the linear relations are assumed to be obeyed exactly, this leads to a universal relationship between the catalytic rate and the oxygen binding energy. Finally, we conclude that for systems obeying these relations, there is a limit to how good a water splitting catalyst an oxidized metal surface can become.

Rossmeisl, J.; Logadottir, A.; Nørskov, J. K.

2005-12-01

86

Fluctuating Helical Asymmetry and Morphology of Snails (Gastropoda) in Divergent Microhabitats at 'Evolution Canyons I and II,' Israel  

PubMed Central

Background Developmental instability of shelled gastropods is measured as deviations from a perfect equiangular (logarithmic) spiral. We studied six species of gastropods at ‘Evolution Canyons I and II’ in Carmel and the Galilee Mountains, Israel, respectively. The xeric, south-facing, ‘African’ slopes and the mesic, north-facing, ‘European’ slopes have dramatically different microclimates and plant communities. Moreover, ‘Evolution Canyon II’ receives more rainfall than ‘Evolution Canyon I.’ Methodology/Principal Findings We examined fluctuating asymmetry, rate of whorl expansion, shell height, and number of rotations of the body suture in six species of terrestrial snails from the two ‘Evolution Canyons.’ The xeric ‘African’ slope should be more stressful to land snails than the ‘European’ slope, and ‘Evolution Canyon I’ should be more stressful than ‘Evolution Canyon II.’ Only Eopolita protensa jebusitica showed marginally significant differences in fluctuating helical asymmetry between the two slopes. Contrary to expectations, asymmetry was marginally greater on the ‘European’ slope. Shells of Levantina spiriplana caesareana at ‘Evolution Canyon I,’ were smaller and more asymmetric than those at ‘Evolution Canyon II.’ Moreover, shell height and number of rotations of the suture were greater on the north-facing slopes of both canyons. Conclusions/Significance Our data is consistent with a trade-off between drought resistance and thermoregulation in snails; Levantina was significantly smaller on the ‘African’ slope, for increasing surface area and thermoregulation, while Eopolita was larger on the ‘African’ slope, for reducing water evaporation. In addition, ‘Evolution Canyon I’ was more stressful than Evolution Canyon II’ for Levantina.

Raz, Shmuel; Schwartz, Nathan P.; Mienis, Hendrik K.; Nevo, Eviatar; Graham, John H.

2012-01-01

87

Fungal farming in a snail  

Microsoft Academic Search

Mutualisms between fungi and fungus-growing animals are model systems for studying coevolution and complex interactions between species. Fungal growing behavior has enabled cultivating animals to rise to major ecological importance, but evolution of farming symbioses is thought to be restricted to three terrestrial insect lineages. Surveys along 2,000 km of North America's Atlantic coast documented that the marine snail Littoraria

Brian R. Silliman; Steven Y. Newell

2003-01-01

88

Epidemiology of cercarial stage of trematodes in freshwater snails from Chiang Mai province, Thailand  

PubMed Central

Objective To investigate the epidemiological situation of cercarial trematodes infection in freshwater snails from different water resources in Chiang Mai province, Thailand. Methods The snail specimens were collected from 13 districts of Chiang Mai province during April 2008 to February 2012. The prevalence of cercarial infection in snails was investigated using the crushing method. The drawing was done with the help of a camera lucida for the morphological study. Results A total of 2?479 snail individuals were collected and classified into 7 families, 11 genera, and 14 species, Among them, 8 snails species were found to be infected with an overall prevalence of 17.27% (428/2?479), which infected with nine groups of cercariae; gymnocephalous cercaria, strigea cercaria, megalurous cercaria, monostome cercaria, parapleurolophocercous cercaria (Haplorchis cercaria), pleurolophocercous cercaria, furcocercous cercaria (Transversotrema cercaria), xiphidiocercaria, and virgulate cercaria. The parapleurolophocercous cercaria was found to be the dominant type among the cercarial infection in the snails (64.25%). Conclusions The various species of snails found in the research location act as the intermediate hosts for the high prevalence of parasitic infection of many species of mammals. This work will provide new information on both the distribution and first intermediate host of trematodes.

Chontananarth, Thapana; Wongsawad, Chalobol

2013-01-01

89

Acute combined exposure to heavy metals (Zn, Cd) blocks memory formation in a freshwater snail.  

PubMed

The effect of heavy metals on species survival is well documented; however, sublethal effects on behaviour and physiology are receiving growing attention. Measurements of changes in activity and respiration are more sensitive to pollutants, and therefore a better early indicator of potentially harmful ecological impacts. We assessed the effect of acute exposure (48 h) to two heavy metals at concentrations below those allowable in municipal drinking water (Zn: 1,100 ?g/l; Cd: 3 ?g/l) on locomotion and respiration using the freshwater snail, Lymnaea stagnalis. In addition we used a novel assessment method, testing the ability of the snail to form memory in the presence of heavy metals in both intact snails, and also snails that had the osphradial nerve severed which connects a chemosensory organ, the osphradium, to the central nervous system. Aerial respiration and locomotion remained unchanged by acute exposure to heavy metals. There was also no effect on memory formation of these metals when administered alone. However, when snails were exposed to these metals in combination memory formation was blocked. Severing the osphradial nerve prevented the memory blocking effect of Zn and Cd, indicating that the snails are sensing these metals in their environment via the osphradium and responding to them as a stressor. Therefore, assessing the ability of this species to form memory is a more sensitive measure of heavy metal pollution than measures of activity, and indicates that the snails' ability to demonstrate behavioural plasticity may be compromised by the presence of these pollutants. PMID:22218978

Byzitter, Jovita; Lukowiak, Ken; Karnik, Vikram; Dalesman, Sarah

2012-04-01

90

Silver speciation in wastewater effluent, surface waters, and pore waters  

SciTech Connect

Silver, inorganic sulfide, and thiol compounds were measured in municipal wastewater effluent, receiving waters, and pore waters from an anoxic lake sediment in order to predict silver speciation in these systems. The authors found submicromolar concentrations of inorganic sulfide even in fully oxic surface water. This inorganic sulfide is likely to exist in the form of colloidal metal sulfides, which have been shown to be stable under oxidizing conditions for periods of several hours. Inorganic sulfide in both the wastewater effluent and receiving waters was found to be 200 to 300 times in excess of silver concentrations, whereas inorganic sulfide in pore waters was 1,000 to 15,000 times in excess of silver concentrations. With sulfide in excess of silver, the authors predict silver sulfide complexes to dominate silver speciation. Thiols were present at low nanomolar levels in pore waters but were not detectable in wastewater effluent or receiving waters. Thiols do not appear to be important to silver speciation in these freshwater systems. Partitioning of silver into particular, colloidal, and dissolved size fractions showed that a significant proportion of silver is in the colloidal and dissolved phases. Dissolved phase concentrations were relatively constant in the treatment plant effluent and receiving waters, suggesting that silver in the <10-kDa size fraction is strongly complexed by ligands that are not significantly affected by aggregation or sorption processes.

Adams, N.W.H.; Kramer, J.R.

1999-12-01

91

The Application of Electric Shock as a Novel Pest Control Method for Apple Snail, Pomacea canaliculata (Gastropoda: Ampullariidae)  

NASA Astrophysics Data System (ADS)

The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be applied intermittently to reduce the amount of energy that is wasted when the snail is in its shell made of one of the insulator. The minimum electric shock required for controlling snails and the time required for movement after application of electric shock to determine the frequency of each electric shock were investigated using two methods; vertical and horizontal application of the electrical stimulation. The results showed that there is a strong correlation between the strength of electric shock and the reaction of the snails, and electric shock made snails inactive when it was applied 0.35 A/m2 in the horizontal direction and 0.45 A/m2 in the vertical direction with water of 11 mS/m. A positive correlation was also found between electric shock and the reaction of the snails and shell height. In comparison with larger snails, the smaller snails had higher threshold levels against electric current density because their shorter feet tended to have lower voltage dorp. Moreover, the frequency of electric shock should be chosen the minimum duration for the inactive condition, and it was approximately 10 seconds. Consequently the direction of electric current should be in the horizontal direction above 0.35 A/m2 and the frequency of electric shock should be less than 10 seconds for practical use. However, electric shock would have to be maintained at greater than 0.35 A/m2 because snails might become habituated to electric shock and water in paddy field would have high electric conductivity.

Yagyu, Yoshihito; Tsuji, Satoshi; Satoh, Saburoh; Yamabe, Chobei

92

Surface Water Applications of Satellite Scatterometry  

NASA Astrophysics Data System (ADS)

We present an overview of the use of satellite scatterometry to detect surface water in liquid and solid phases for various regional geophysical applications. We study scatterometer/radiometer signatures of surface soil moisture with in-situ data from SCAN, Oklahoma Mesonet, and NCDC/GSOD stations. Results indicate scatterometer data can detect and inventory wet surface events due to rains to determine the regional frequency of surface water cycling. Animated time-series of scatterometer data over the SMEX (Soil Moisture EXperiment) region in mid-west US illustrate the monitoring of surface water variabilities over large scales. An automated flood processing algorithm implemented at the Jet Propulsion Laboratory (JPL) provides daily updated data over the world to the Dartmouth Flood Observatory (DFO) for early flood detections. We verify the flooded areas with MODIS clear-sky observations. We obtain weekly wetland results in Africa, Asia, North America, and South America. We show wetland monitoring results over the Eastern Arkansas - Mississippi River Valley with a comparison of the maximum extent to MODIS standard water. We investigate scatterometer signatures of snowmelt with field experiments carried out in Alaska to develop algorithms for snowmelt detection over the northern hemisphere. We present animated snowmelt results over the Lena River region in Siberia leading to floods (in 2000-2003) including the 2001 Lena Flood of the Century. Snowmelt timing parameters derived from scatterometer data are appropriate for assimilation into hydrology models for river discharge estimate and for flood forecast. We map ice cover over the Great Lakes and compare the results with observations from US Coast Guard (USCG) Mackinaw icebreaker and from a web camera on Granite Island. Over Greenland, we map and monitor surface melt areas and compare the results to in-situ measurements from the Greenland Climate Network (GC-Net). Results show extensive melt over the Greenland ice surface in 2002 in record amounts. We carried out a sea-ice mapping field experiment using the USCG Healy icebreaker over the Barents Sea in 2001. We detect a peculiar sea-ice barrier east of Svalbard, which poses hazards to ship navigation east of Svalbard. We map sea ice melt and refreezing areas by combining QuikSCAT and SSM/I products over the Arctic sea ice with verification from the Canadian C-ICE field experiment. Finally, we discuss limitations of current satellite scatterometers and the need for future advanced satellite sensors for surface-water applications.

Nghiem, S. V.; Barber, D. G.; Brakenridge, G. R.; Leshkevich, G. A.; Markus, T.; Neumann, G.; Njoku, E. G.; Perovich, D. K.; Steffen, K.; Sturm, M.; van Woert, M. L.

2003-12-01

93

Analysis of snail genes in the crustacean Parhyale hawaiensis: insight into snail gene family evolution.  

PubMed

The transcriptional repressor snail was first discovered in Drosophila melanogaster, where it initially plays a role in gastrulation and mesoderm formation, and later plays a role in neurogenesis. Among arthropods, this role of snail appears to be conserved in the insects Tribolium and Anopheles gambiae, but not in the chelicerates Cupiennius salei and Achaearanea tepidariorum, the myriapod Glomeris marginata, or the Branchiopod crustacean Daphnia magna. These data imply that within arthropoda, snail acquired its role in gastrulation and mesoderm formation in the insect lineage. However, crustaceans are a diverse group with several major taxa, making analysis of more crustaceans necessary to potentially understand the ancestral role of snail in Pancrustacea (crustaceans + insects) and thus in the ancestor of insects as well. To address these questions, we examined the snail family in the Malacostracan crustacean Parhyale hawaiensis. We found three snail homologs, Ph-snail1, Ph-snail2 and Ph-snail3, and one scratch homolog, Ph-scratch. Parhyale snail genes are expressed after gastrulation, during germband formation and elongation. Ph-snail1, Ph-snail2, and Ph-snail3 are expressed in distinct patterns in the neuroectoderm. Ph-snail1 is the only Parhyale snail gene expressed in the mesoderm, where its expression cycles in the mesodermal stem cells, called mesoteloblasts. The mesoteloblasts go through a series of cycles, where each cycle is composed of a migration phase and a division phase. Ph-snail1 is expressed during the migration phase, but not during the division phase. We found that as each mesoteloblast division produces one segment's worth of mesoderm, Ph-snail1 expression is linked to both the cell cycle and the segmental production of mesoderm. PMID:22466422

Hannibal, Roberta L; Price, Alivia L; Parchem, Ronald J; Patel, Nipam H

2012-05-01

94

Uncertainty in surface water flood risk modelling  

NASA Astrophysics Data System (ADS)

Two thirds of the flooding that occurred in the UK during summer 2007 was as a result of surface water (otherwise known as ‘pluvial') rather than river or coastal flooding. In response, the Environment Agency and Interim Pitt Reviews have highlighted the need for surface water risk mapping and warning tools to identify, and prepare for, flooding induced by heavy rainfall events. This need is compounded by the likely increase in rainfall intensities due to climate change. The Association of British Insurers has called for the Environment Agency to commission nationwide flood risk maps showing the relative risk of flooding from all sources. At the wider European scale, the recently-published EC Directive on the assessment and management of flood risks will require Member States to evaluate, map and model flood risk from a variety of sources. As such, there is now a clear and immediate requirement for the development of techniques for assessing and managing surface water flood risk across large areas. This paper describes an approach for integrating rainfall, drainage network and high-resolution topographic data using Flowroute™, a high-resolution flood mapping and modelling platform, to produce deterministic surface water flood risk maps. Information is provided from UK case studies to enable assessment and validation of modelled results using historical flood information and insurance claims data. Flowroute was co-developed with flood scientists at Cambridge University specifically to simulate river dynamics and floodplain inundation in complex, congested urban areas in a highly computationally efficient manner. It utilises high-resolution topographic information to route flows around individual buildings so as to enable the prediction of flood depths, extents, durations and velocities. As such, the model forms an ideal platform for the development of surface water flood risk modelling and mapping capabilities. The 2-dimensional component of Flowroute employs uniform flow formulae (Manning's Equation) to direct flow over the model domain, sourcing water from the channel or sea so as to provide a detailed representation of river and coastal flood risk. The initial development step was to include spatially-distributed rainfall as a new source term within the model domain. This required optimisation to improve computational efficiency, given the ubiquity of ‘wet' cells early on in the simulation. Collaboration with UK water companies has provided detailed drainage information, and from this a simplified representation of the drainage system has been included in the model via the inclusion of sinks and sources of water from the drainage network. This approach has clear advantages relative to a fully coupled method both in terms of reduced input data requirements and computational overhead. Further, given the difficulties associated with obtaining drainage information over large areas, tests were conducted to evaluate uncertainties associated with excluding drainage information and the impact that this has upon flood model predictions. This information can be used, for example, to inform insurance underwriting strategies and loss estimation as well as for emergency response and planning purposes. The Flowroute surface-water flood risk platform enables efficient mapping of areas sensitive to flooding from high-intensity rainfall events due to topography and drainage infrastructure. As such, the technology has widespread potential for use as a risk mapping tool by the UK Environment Agency, European Member States, water authorities, local governments and the insurance industry. Keywords: Surface water flooding, Model Uncertainty, Insurance Underwriting, Flood inundation modelling, Risk mapping.

Butler, J. B.; Martin, D. N.; Roberts, E.; Domuah, R.

2009-04-01

95

Arsenic speciation in freshwater snails and its life cycle variation.  

PubMed

Terrestrial snails are consumed by humans occasionally and they are an important food source for many creatures including fish and birds. Little is known about arsenic speciation in these gastropods, let alone life cycle variations. Here we report on the arsenic speciation in freshwater snails from Pender Island and Vancouver Island, B.C., Canada, which was determined on methanol/water extracts (43-59% extraction efficiency) by using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and HPLC-electrospray tandem mass spectrometry. The tetramethylarsonium ion, oxo-arsenosugars and thio-arsenosugars are the main arsenic species encountered. Arsenobetaine, which is commonly found in the marine environment, is minor. Live bearing snails Viviparidae sp. from Pender Island were maintained in aquaria and the arsenic speciation in the unborn, newly born, and adult animals was monitored. Oxo-arsenosugars predominate in the adults, whereas thio-arsenosugars seem to predominate in juveniles, suggesting that these arsenicals are snail metabolites. PMID:22193982

Lai, Vivian W-M; Kanaki, Katerina; Pergantis, Spiros A; Cullen, William R; Reimer, Kenneth J

2012-03-01

96

Source Water Assessment for the Las Vegas Valley Surface Waters  

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

97

Failure of transmission of low-pathogenic avian influenza virus between Mallards and freshwater snails: an experimental evaluation.  

PubMed

In aquatic bird populations, the ability of avian influenza (AI) viruses to remain infectious in water for extended periods provides a mechanism that allows viral transmission to occur long after shedding birds have left the area. However, this also exposes other aquatic organisms, including freshwater invertebrates, to AI viruses. Previous researchers found that AI viral RNA can be sequestered in snail tissues. Using an experimental approach, we determined whether freshwater snails (Physa acuta and Physa gyrina) can infect waterfowl with AI viruses by serving as a means of transmission between infected and naïve waterfowl via ingestion. In our first experiment, we exposed 20 Physa spp. snails to an AI virus (H3N8) and inoculated embryonated specific pathogen-free (SPF) chicken eggs with the homogenized snail tissues. Sequestered AI viruses remain infectious in snail tissues; 10% of the exposed snail tissues infected SPF eggs. In a second experiment, we exposed snails to water contaminated with feces of AI virus-inoculated Mallards (Anas platyrhynchos) to evaluate whether ingestion of exposed freshwater snails was an alternate route of AI virus transmission to waterfowl. None of the immunologically naïve Mallards developed an infection, indicating that transmission via ingestion likely did not occur. Our results suggest that this particular trophic interaction may not play an important role in the transmission of AI viruses in aquatic habitats. PMID:24502718

Oesterle, Paul T; Huyvaert, Kathryn P; Orahood, Darcy; Mooers, Nicole; Sullivan, Heather; Franklin, Alan B; Root, J Jeffrey

2013-10-01

98

Population studies on Oncomelania quadrasi, the snail intermediate host of Schistosoma japonicum, in the Philippines. 5. Quantitative analysis on successful snail control by land reclamation.  

PubMed

For the control of Oncomelania quadrasi, environmental modifications, i.e., clearing of vegetation, leveling of swampy depression and draining of stagnant water by channeling and excavation were carried out at 3 areas in Leyte, Philippines from 1974 to 1977. The change of snail population resulted in the land reclamation was evaluated by the methods previously developed by the population studies on this snail. As a result of statistical analysis based on y = log(x + 0.01) transformation and the antilogarithmic mean density A-y = (antilog -y) -0.01, the reduction of snail population was observed at 13 out of 18 sites studied at 3 project areas and the significant reduction was statistically confirmed at 9 sites of them. Particularly at Dagami area, which was a wide and heavily snail-infested land adjacent to Dagami Poblacion, the reduction rate of snail density reached 87.7% to 99.2% and some wet depressions have been converted into good rice fields with little snail infestation at the last survey. PMID:3090317

Makiya, K; Tanaka, H; Bañez, E; Blas, B L; Santos, A T

1986-04-01

99

Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water  

USGS Publications Warehouse

This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological investigations of the near-surface environment.

Edited by Rosenberry, Donald O.; LaBaugh, James W.

2008-01-01

100

Atmospheric radiation model for water surfaces  

NASA Technical Reports Server (NTRS)

An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

1982-01-01

101

Assessing nitrogen pressures on European surface water  

NASA Astrophysics Data System (ADS)

The European environmental legislation on water, in particular the 2000 Water Framework Directive, requires the evaluation of nutrient pressures and the assessment of mitigation measures at the river basin scale. Models have been identified as tools that can contribute to fulfill these requirements. The objective of this research was the implementation of a modeling approach (Geospatial Regression Equation for European Nutrient losses (GREEN)) to assess the actual nitrogen pressures on surface water quality at medium and large basin scale (European scale) using readily available data. In particular the aim was to estimate diffuse nitrogen emissions into surface waters, contributions by different sources (point and diffuse) to the nitrate load in rivers, and nitrogen retention in river systems. A comprehensive database including nutrient sources and physical watershed characteristics was built at the European scale. The modeling partially or entirely covered some of the larger and more populated European river basins, including the Danube, Rhine, Elbe, Weser, and Ems in Germany, the Seine and Rhone in France, and the Meuse basin shared by France and Belgium. The model calibration was satisfactory for all basins. The source contribution to the in-stream nitrogen load, together with the diffuse nitrogen emissions and river nitrogen retention were estimated and were found to be in the range of values reported in the literature. Finally, the model results were extrapolated to estimate the diffuse nitrogen emission and source apportionment at the European scale.

Grizzetti, B.; Bouraoui, F.; de Marsily, G.

2008-12-01

102

Studies of mineral-water surfaces  

SciTech Connect

In this chapter we discuss the application of inelastic and quasielastic neutron scattering to the elucidation of the structure, energetics, and dynamics of water confined on the surfaces of mineral oxide nanoparticles. We begin by highlighting recent advancements in this active field of research before providing a brief review of the theory underpinning inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) techniques. We then discuss examples illustrating the use of neutron scattering methods for studying hydration layers that are an integral part of the nanoparticle structure. The first investigation of this kind, namely the INS analysis of hydrated ZrO2 nanoparticles, is described, as well as a later, complementary QENS study that allowed for the dynamics of diffusion of the water molecules within the hydration layer to be examined in detail. The diverse range of information available from INS experiments is illustrated by a recent study combining INS with calorimetric experiments that elucidated the thermodynamic properties of adsorbed water on anatase (TiO2) nanoparticles. To emphasize the importance of molecular dynamics (MD) simulations for deconvoluting complex QENS spectra, we describe both the MD and QENS analysis of rutile (TiO2) and cassiterite (SnO2) nanoparticle systems and show that, when combined, data obtained by these two complementary methods can provide a complete description of the motion of the water molecules on the nanoparticle surface. We close with a glimpse into the future for this thriving field of research.

Ross, Dr. Nancy [Virginia Polytechnic Institute and State University (Virginia Tech); Spencer, Elinor [Virginia Polytechnic Institute and State University (Virginia Tech); Levchenko, Dr. Andrey [University of California, Davis; Wesolowski, David J [ORNL; Cole, David R [ORNL; Mamontov, Eugene [ORNL; Vlcek, L. [Vanderbilt University

2009-01-01

103

River regulation and interactions groundwater - surface water  

NASA Astrophysics Data System (ADS)

The determination of a minimum acceptable flow in a river affected by regulation is a major task in management of hydropower development. The Norwegian Water Resources and Energy Directorate (NVE), responsible for administrating the nation's water resources, requires an objective system that takes into account the needs of the developer and the rivers environment such as water quality, river biota, landscape, erosion and groundwater. A research project has been initiated with focus on interactions between groundwater and surface water. The purpose of the project is to provide the licensing authorities with tools for quantitative assessment of the effects of regulation on groundwater resources and at the same time the effect of groundwater abstraction on river flows. A small, urbanised alluvial plain (2 km^2) by the river Glomma in Central Southern Norway is used as a case study. The local aquifer consists of heterogeneous glaciofluvial and fluvial deposit, mainly sand and gravel. Two three-dimensional numerical models (Visual Modflow 3.0 and Feflow 5.0) have been used for this study. The models were calibrated with hydro-geological data collected in the field. Aquifer and river sediment has been examined by use of Ground Penetrating Radar (GPR) and soil samples collection. Preferential flow has been examined by tracer tests. Water level, temperature and electric conductivity have been recorded in both aquifer and river. Hydro-climatic regime has been analysed by statistical tools. The first task of the project is to carry out water balance studies in order to estimate the change in rate of groundwater recharge from and to the river along a normal hydrologic year with snowmelting, flood, and baseflow. The second task is to analyse the potential effect of change in the river water regime (due to regulation and consecutive clogging) on groundwater resources and their interaction with stream water.

Colleuille, H.; Wong, W. K.; Dimakis, P.; Pedersen, T. S.

2003-04-01

104

Snail modulates cell metabolism in MDCK cells  

SciTech Connect

Highlights: ? MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ? MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ? TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ? MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ? MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of key enzymes. This results in enhanced glucose dependency and leads to cell death under low-glucose conditions. On the other hand, the reduced requirements for oxygen and nutrients from the surrounding environment, might confer the resistance to cell death induced by hypoxia and malnutrition.

Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan)] [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

2013-03-22

105

Chemical composition of Texas surface waters, 1949  

USGS Publications Warehouse

This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, and nitrate are reported in parts per million. The quantity of dissolved solids is given in tons per acre-foot, tons per day (if discharge records are available), and parts per million. The total and non-carbonate hardness are reported as parts per million calcium carbonate (CaCO3). For those analyses where sodium and potassium are reported separately, "recent sodium" will include the equivalent quantity of sodium only. In analyses where sodium and potassium were calculated and reported as a combined value, the "percent sodium" will include the equivalent quantity of sodium and potassium. Weighted average analyses are given for most daily sampling stations. The weighted average analysis represent approximately the composition of water that would be found in a reservoir containing all the water passing a given station during the year after through mixing in the reservoir. Samples were analyzed according to method regularly used by the Geological Survey. These methods are essentially the same or are modifications of methods described in recognized authoritative publications for mineral analysis of water samples. These quality of water records have been collected as part of the cooperative investigations of the water resources of Texas conducted by the Geological Survey and the Texas Board of Water Engineers. Much of the work would have been impossible without the support of the following Federal State, and local agencies The United States Bureau of Reclamation, U. S. Corps of Engineers, Brazos River Conservation and Reclamation District, Lower Colorado River Authority, Red Bluff Water Power Control District, City of Amarillo, City of Abilene, and City of Forth Worth. The investigations were under the firection of Burdge Irelan, District Chemist, Austin, Texas. Analyses of water samples were made by Clara J. Carter, Lee J. Freeman, Homer D. Smith, Dorothy M. Suttle, DeForrest E. Weaver, and Clarence T. Welborn. Calculations of weighted averages were made by James R. Avrett, Burdge Irelan, Dorothy M. Suttle, and DeFor

Irelan, Burdge

1950-01-01

106

Celss nutrition system utilizing snails  

NASA Astrophysics Data System (ADS)

At the 40th IAF Congress in Malaga, a nutrition system for a lunar base CELSS was presented. A lunar base with a total of eight crew members was envisaged. In this paper, four species of plants—rice, soybean, lettuce and strawberry—were introduced to the system. These plants were sufficient to satisfy fundamental nutritional needs of the crew members. The supply of nutrition from plants and the human nutritional requirements could almost be balanced. Our study revealed that the necessary plant cultivation area per crew member would be nearly 40 m 3 in the lunar base. The sources of nutrition considered in the study were energy, sugar, fat, amino acids, inorganic salt and vitamins; however, calcium, vitamin B 2, vitamin A and sodium were found to be lacking. Therefore, a subsystem to supply these elements is of considerable value. In this paper, we report on a study for breeding snails and utilizing meat as food. Nutrients supplied from snails are shown to compensate for the abovementioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of closed ecological life support system.

Midorikawa, Y.; Fujii, T.; Ohira, A.; Nitta, K.

107

Fungal farming in a snail.  

PubMed

Mutualisms between fungi and fungus-growing animals are model systems for studying coevolution and complex interactions between species. Fungal growing behavior has enabled cultivating animals to rise to major ecological importance, but evolution of farming symbioses is thought to be restricted to three terrestrial insect lineages. Surveys along 2,000 km of North America's Atlantic coast documented that the marine snail Littoraria irrorata grazes fungus-infected wounds on live marsh grass throughout its range. Field experiments demonstrate a facultative, farming mutualism between Littoraria and intertidal fungi. Snails graze live grass primarily not to feed but to prepare substrate for fungal growth and consume invasive fungi. Fungal removal experiments show that snails and fungi act synergistically to suppress marsh grass production. These results provide a case of fungus farming in the marine environment and outside the class Insecta and reveal a previously undemonstrated ecological mechanism (i.e., facilitation of fungal invasion) by which grazers can exert top-down control of marine plant production. PMID:14657360

Silliman, Brian R; Newell, Steven Y

2003-12-23

108

A predatory land snail invades central-western Argentina  

Microsoft Academic Search

The pulmonate land snail, Rumina decollata, is a highly invasive gastropod adapted to arid conditions, and native from the Mediterranean area. It was recorded for the\\u000a first time in Argentina in 1988, in the northeastern Pampas of the Buenos Aires Province, a region characterized by a humid\\u000a mesothermal climate with no water deficit. In the present contribution, we report the

Claudio G. De Francesco; Humberto Lagiglia

2007-01-01

109

Lawrence Livermore National Laboratory Surface Water Protection: A Watershed Approach.  

National Technical Information Service (NTIS)

This surface water protection plan (plan) provides an overview of the management efforts implemented at Lawrence Livermore National Laboratory (LLNL) that support a watershed approach to protect surface water. This plan fulfills a requirement in the Depar...

J. Coty

2009-01-01

110

Surface crystallization of supercooled water in clouds  

PubMed Central

The process by which liquid cloud droplets homogeneously crystallize into ice is still not well understood. The ice nucleation process based on the standard and classical theory of homogeneous freezing initiates within the interior volume of a cloud droplet. Current experimental data on homogeneous freezing rates of ice in droplets of supercooled water, both in air and emulsion oil samples, show considerable scatter. For example, at ?33°C, the reported volume-based freezing rates of ice in supercooled water vary by as many as 5 orders of magnitude, which is well outside the range of measurement uncertainties. Here, we show that the process of ice nucleus formation at the air (or oil)-liquid water interface may help to explain why experimental results on ice nucleation rates yield different results in different ambient phases. Our results also suggest that surface crystallization of ice in cloud droplets can explain why low amounts of supercooled water have been observed in the atmosphere near ?40°C.

Tabazadeh, A.; Djikaev, Y. S.; Reiss, H.

2002-01-01

111

Relaxations and Interfacial Water Ordering at the Corundum (110) Surface  

SciTech Connect

In situ high resolution specular X-ray reflectivity measurements were used to examine relaxations and interfacial water ordering occurring at the corundum (110)-water interface. Sample preparation affected the resulting surface structure. Annealing in air at 1373 K produced a reconstructed surface formed through an apparently ordered aluminum vacancy. The effect of the reconstruction on in-plane periodicity was not determined. The remaining aluminum sites on the surface maintain full coordination by oxygen and the surface was coated with a layer of physically adsorbed water. Ordering of water further from the surface was not observed. Acid etching of this surface and preparing a surface through annealing at 723 K both produced an unreconstructed surface with identical relaxations and water ordering. Relaxations were confined primarily to the top {approx}4 {angstrom} of the surface and were dominated by an increased distribution width of the fully occupied surface aluminum site and outward relaxation of the oxygen surface functional groups. A layer of adsorbed water fully coated the surface and occurred in two distinct sites. Water above this showed signs of layering and indicated that water ordering extended 7-10 {angstrom} from the surface. Relaxations and the arrangement of interfacial water were nearly identical on both the unreconstructed corundum and isostructural hematite (110) surfaces. Comparison to corundum and hematite (012) suggests that the arrangement of interfacial water is primarily controlled by mineral surface structure.

Catalano, Jeffrey G. (WU)

2010-09-17

112

Surface-water quality-assurance plan for the USGS Georgia Water Science Center, 2010  

USGS Publications Warehouse

The U.S. Geological Survey requires that each Water Science Center prepare a surface-water quality-assurance plan to describe policies and procedures that ensure high quality surface-water data collection, processing, analysis, computer storage, and publication. The Georgia Water Science Center's standards, policies, and procedures for activities related to the collection, processing, analysis, computer storage, and publication of surface-water data are documented in this Surface-Water Quality-Assurance Plan for 2010.

Gotvald, Anthony J.

2010-01-01

113

Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations  

NASA Technical Reports Server (NTRS)

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on groundwater table observations, and with estimates of total water storage variations from the GRACE satellites mission. Due to the difficulty in estimating area-averaged seasonal groundwater storage variations from point observations of groundwater levels, it is uncertain whether WaterGAP underestimates actual variations or not. We conclude that WaterGAP possibly overestimates water withdrawals in the High Plains aquifer where impact of human water use on water storage is readily discernible based on WaterGAP calculations and groundwater observations. No final conclusion can be drawn regarding the possibility of monitoring water withdrawals in the High Plains aquifer using GRACE. For the less intensively irrigated Mississippi basin, observed and modeled seasonal groundwater storage reveals a discernible impact of water withdrawals in the basin, but this is not the case for total water storage such that water withdrawals at the scale of the whole Mississippi basin cannot be monitored by GRACE.

Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

2011-01-01

114

Impact of water withdrawals from groundwater and surface water on continental water storage variations  

NASA Astrophysics Data System (ADS)

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 km3/year during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 km3/year during 1998-2002. It is the sum of the net abstraction of 250 km3/year of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/year of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on groundwater table observations, and with estimates of total water storage variations from the GRACE satellites mission. Due to the difficulty in estimating area-averaged seasonal groundwater storage variations from point observations of groundwater levels, it is uncertain whether WaterGAP underestimates actual variations or not. We conclude that WaterGAP possibly overestimates water withdrawals in the High Plains aquifer where impact of human water use on water storage is readily discernible based on WaterGAP calculations and groundwater observations. No final conclusion can be drawn regarding the possibility of monitoring water withdrawals in the High Plains aquifer using GRACE. For the less intensively irrigated Mississippi basin, observed and modeled seasonal groundwater storage reveals a discernible impact of water withdrawals in the basin, but this is not the case for total water storage such that water withdrawals at the scale of the whole Mississippi basin cannot be monitored by GRACE.

Döll, P.; Hoffmann-Dobrev, H.; Portmann, F. T.; Siebert, S.; Eicker, A.; Rodell, M.; Strassberg, G.; Scanlon, B. R.

2012-09-01

115

Land Snails of the Lucile Caves ACEC.  

National Technical Information Service (NTIS)

A land snail survey was conducted on the Lucile Caves ACES and vicinity in 1993-1994 as part of a larger survey of the Lower Salmon River valley land snail fauna. Information gathered from earlier surveys in 1989 - 1993 was also included. The area was kno...

T. J. Frest E. J. Johannes

1997-01-01

116

Deterministic assembly of land snail communities according to species size and diet.  

PubMed

1. We investigated whether coexisting snail species in 145 treeless fen communities in the Western Carpathian Mountains differed more in size and diet than would be expected by chance, as predicted for traits commonly associated with competition and differential resource acquisition under limiting similarity theory. 2. Contrary to expectations, coexisting snail species were no more different in body size than expected by chance under a null model. However, variation in body size played a significant role in structuring snail communities: coexisting snail species were significantly more similar with respect to body size. 3. We developed two new test statistics to expand our investigation of limiting similarity to include diet, a nominal trait. We tested whether communities of snails were characterized by a greater richness of diet, and whether different diets were represented more or less evenly within communities. Communities of snails were significantly less evenly distributed than expected by chance, with detritivores being over-represented relative to predatory strategies. 4. We also examined the effect of water pH and conductivity, herbaceous cover, and bryophyte and vascular plant richness, on these trends by examining how the effect size of our tests varied across these gradients. Convergence in species size increased with increasing habitat pH. Specifically, smaller snail species were over-represented in fen communities in general, and this effect was accentuated in increasingly calcareous fens. 5. Theory predicts that traits related strongly to environmental conditions are more likely to be convergent. Our findings support this suggestion, as small snail species have an advantage in tolerating freezing conditions over winter when refuges are limited. 6. These results add to the growing body of literature demonstrating that variation in body size and diet play a strong role in structuring communities, although frequently in ways not predicted by limiting similarity theory. Finally, our results increase our understanding of how species are assembled non-randomly into communities with respect to important traits. PMID:20345504

Schamp, Brandon; Horsák, Michal; Hájek, Michal

2010-07-01

117

Biological characteristics and control of intermediate snail host of Schistosoma japonicum.  

PubMed

Except for imported cases, we have had no new Schistosoma japonicum infection in Japan since 1977. But there are still two habitats of the intermediate snail host: Oncomelania nosophora in the previous endemic areas of Kofu Basin and Obitsu. O. nosophora from Kofu Basin and Obitsu are susceptible to Chinese and Philippine strains of S. japonicum. The number of immigrants from current endemic areas in China or the Philippines is increasing. In order to prevent re-emerging of S. japonicum infections in Japan, we should continue monitoring on those existing snail hosts and investigate an adequate quarantine system. In Japan, elimination of schistosomiasis has been mainly accomplished by control of the snail host. As measures of snail control, cement-lining of ditches and chemical mollusciciding were most effective in Japan. But the cost of this joint program is too expensive compared with health budget in almost developing countries. In endemic areas of Japan, land reformation from paddy field to fruit farm was also effective. The intermediate snail host in the Philippines, Oncomelania quadrasi is much more aquatic than O. nosophora. For control of O. quadrasi, small drainage of the water and land reclamation from swampy field to rice-field were effective. Based on biological characteristics of Oncomelania spp., we can modify the past successful snail control program in Japan to be adapted ecologically and economically to each endemic area of developing countries. PMID:14665400

Ohmae, Hiroshi; Iwanaga, Yuzuru; Nara, Takeshi; Matsuda, Hajime; Yasuraoka, Kazuo

2003-12-01

118

Extreme surface propensity of halide ions in water.  

PubMed

Water possesses an extremely high polarity, making it a unique solvent for salts. Indeed, aqueous electrolyte solutions are ubiquitous in the atmosphere, biology, energy applications and industrial processes. For many processes, chemical reactions at the water surface are rate determining, and the nature and concentration of the surface-bound electrolytes are of paramount importance, as they determine the water structure and thereby surface reactivity. Here we investigate the dynamics of water molecules at the surface of sodium chloride and sodium iodide solutions, using surface-specific femtosecond vibrational spectroscopy. We quantify the interfacial ion density through the reduced energy transfer rates between water molecules resulting from the lowered effective interfacial density of water molecules, as water is displaced by surface active ions. Our results reveal remarkably high surface propensities for halogenic anions, higher for iodide than for chloride ions, corresponding to surface ion concentrations several times that of the bulk. PMID:24899106

Piatkowski, Lukasz; Zhang, Zhen; Backus, Ellen H G; Bakker, Huib J; Bonn, Mischa

2014-01-01

119

Water Resources Data, Florida, Water Year 2001, Volume 3A. Southwest Florida Surface Water  

USGS Publications Warehouse

Water resources data for the 2001 water year in Florida consist of continuous or daily discharges for 406 streams, periodic discharge for 12 streams, continuous daily stage for 142 streams, periodic stage for 12 streams, peak stage and discharge for 37 streams, continuous or daily elevations for 11 lakes, periodic elevations for 30 lakes; continuous ground-water levels for 424 wells, periodic ground-water levels for 1,426 wells, and quality-of-water data for 80 surface-water sites and 245 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 83 streams, periodic discharge for 10 streams, continuous or daily stage for 43 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 37 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Stoker, Y. E.; Kane, R. L.; Fletcher, W. L.

2002-01-01

120

Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water  

USGS Publications Warehouse

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Kane, R. L.; Fletcher, W. L.

2004-01-01

121

Water resources data, Florida, water year 2005. Volume 3A: Southwest Florida surface water  

USGS Publications Warehouse

Water resources data for the 2005 water year in Florida consist of continuous or daily discharges for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 streams, peak stage for 28 streams and peak discharge for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, and quality-of-water data for 211 surface-water sites and 208 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains records for continuous or daily discharge for 113 streams, periodic discharge for 4 streams, continuous or daily stage for 80 streams, periodic stage for 2 stream, peak stage and discharge for 8 streams, continuous or daily elevations for 3 lakes, continous or daily elevations for 3 lakes, and quality of water for 75 surface water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Kane, Richard L.; Dickman, Mark

2005-01-01

122

Water resources data, Florida, water year 2004, volume 3A: southwest Florida surface water  

USGS Publications Warehouse

Water resources data for the 2004 water year in Florida consist of continuous or daily discharges for 405 streams, periodic discharge for 12 streams, continuous daily stage for 159 streams, periodic stage for 19 streams, peak stage for 30 streams and peak discharge for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 408 wells, periodic ground-water levels for 1,188 wells, and quality-of-water data for 140 surface-water sites and 240 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 104 streams, periodic discharge for 6 streams, continuous or daily stage for 36 streams, periodic stage for 14 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 3 lakes, and quality-of-water data for 58 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Kane, Richard L.

2004-01-01

123

Water Resources Data, Florida, Water Year 2002, Volume 3A. Southwest Florida Surface Water  

USGS Publications Warehouse

Water resources data for the 2002 water year in Florida consist of continuous or daily discharges for 392 streams, periodic discharge for 15 streams, continuous daily stage for 191 streams, periodic stage for 13 streams, peak stage for 33 streams and peak discharge for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes; continuous ground-water levels for 418 wells, periodic ground-water levels for 1,287 wells, and quality-of-water data for 116 surface-water sites and 291 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 99 streams, periodic discharge for 11 streams, continuous or daily stage for 63 streams, peak stage and discharge for 7 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 59 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Kane, R. L.; Fletcher, W. L.

2003-01-01

124

Environmental calcium modifies induced defences in snails.  

PubMed Central

Inducible defences are adaptive phenotypes that arise in response to predation threats. Such plasticity incurs costs to individuals, but there has been little interest in how such induced traits in animals may be constrained by environmental factors. Here, we demonstrate that calcium availability interacts with predation cues to modify snail shell growth and form. Small snails increased their growth and were heavier when exposed to fish chemical cues, but this response was calcium limited. There was also an interactive effect of fish cues and calcium on the shell growth of larger snails, but shell strength and aperture narrowness were affected by calcium alone. For small snails, behavioural avoidance was greatest for snails exhibiting least morphological plasticity, suggesting a trade-off. There was no trade-off of somatic growth with plasticity. We suggest that the expression of defensive traits in molluscs can be constrained by calcium availability, which has implications for molluscan ecology and evolution.

Rundle, Simon D; Spicer, John I; Coleman, Ross A; Vosper, Jo; Soane, Julie

2004-01-01

125

Surface water quality-assurance plan, U.S. Geological Survey, Kentucky Water Science Center, water year 2006  

USGS Publications Warehouse

This Surface Water Quality-Assurance Plan documents the standards, policies, and procedures used by the Kentucky Water Science Center for activities related to the collection, processing, storage, analysis, and publication of surface-water data.

Griffin, Michael S.

2006-01-01

126

Snail Protein Family in Drosophila Neurogenesis: a Dissertation  

Microsoft Academic Search

The Snail protein functions as a transcriptional regulator to establish early mesodermal cell fate in Drosophila. Later, in germ band-extended embryos, Snail is considered a pan-neural protein based on its extensive expression in neuroblasts. The evidence presented in thesis links snail expression and function in CNS. Cloning and functional characterization of a novel snail homologue, in Drosophila, are also described

Shovon I. Ashraf

2001-01-01

127

The Surface Water and Ocean Topography Mission: Observing Terrestrial Surface Water and Oceanic Submesoscale Eddies  

Microsoft Academic Search

The elevation of the ocean surface has been measured for over two decades from spaceborne altimeters. However, existing altimeter measurements are not adequate to characterize the dynamic variations of most inland water bodies, nor of ocean eddies at scales of less than about 100 km, notwithstanding that such eddies play a key role in ocean circulation and climate change. For

Michael Durand; Lee-Lueng Fu; Dennis P. Lettenmaier; Douglas E. Alsdorf; Ernesto Rodriguez; Daniel Esteban-Fernandez

2010-01-01

128

Discrete movements of foot epithelium during adhesive locomotion of a land snail.  

PubMed

During the adhesive locomotion of land snails a series of short dark transverse bands, called pedal or foot waves, is visible ifa moving snail's ventral surface is observed through a sheet of glass. Moreover, the mucus secreted from the pedal glands and some pedal epithelial cells forms a thin layer which acts as a glue augmenting adherence, while also acting as a lubricant under the moving parts of the snail's foot. The relationships between velocity and the frequency of pedal waves as well as changes in the volume of small air bubbles under foot waves were analyzed by means of digital recordings made through a glass sheet on which the snails were moving. On the ventral surface of a moving snail foot, the adhering parts of the foot constituted about 80% of the total area, while several moving parts only about 20%. The single moving region of the foot (the pedal wave) amounted to about 3% of snail length. The epithelium in the region of the pedal wave was arched above the substrate and was also more wrinkled than the stationary epithelium, which enabled the forward motion of each specific point of epithelium during the passage of a pedal wave above it. The actual area of epithelium engaged by a pedal wave was at least 30% greater than the area of the epithelium as recorded through a glass sheet. In the region of the pedal wave, the tiny subepithelial muscles acting on the epithelium move it up in the front part of the wave, and then down at the end of the wave, operating vertically in relation to the substrate. In the middle part of the wave, the epithelium only moves forward. In summary, during the adhesive locomotion of snails, the horizontal movement of the ventral surface epithelium proceeds as temporally separate phases of upward, forward and downward movement. PMID:22428315

Tyrakowski, Tomasz; Kaczorowski, Piotr; Paw?owicz, Wojciech; Zió?kowski, Marcin; Smuszkiewicz, Piotr; Trojanowska, Iwona; Marsza?ek, Andrzej; Zebrowska, Ma?gorzata; Lutowska, Monika; Kopczy?ska, Ewa; Lampka, Magdalena; Ho?y?ska-Iwan, Iga; Piskorska, Elzbieta

2012-01-01

129

Water Surface Turbulance and Internal Waves, Norfolk, VA, USA  

NASA Technical Reports Server (NTRS)

Norfolk and the mouth of the Chesapeake Bay, VA, (37.5N, 75.5W) was exposed in sunglint conditions to emphasizes water surface patterns. Outgoing tides from the bay generate considerable turbulence as they encounter coastal ocean currents and can be observed as differences in the reflective properties of the water surface. Smooth flowing water has high reflectivity. Turbulent water has a rough surface and low reflectance. Ship wakes can also be seen.

1991-01-01

130

Remote sensing analysis of surface water in a mining area  

NASA Astrophysics Data System (ADS)

The exploitation of the coal has brought about pollution on the surface water. That was seriously harmful to environment. Thinking of the Feicheng mining area as research area, authors tested the reflectance spectrum of waters and analyzed these curves. The paper made the computer image processing by TM computer compatible tape. Combining routine monitoring methods and TM images, the surface water of mining area was comprehensively analyzed furthermore. This paper provided a rapidly and economical method of monitoring mining area surface water.

Han, Zhen; Yang, Fengjie; Feng, Xianghua; Liu, Jiwei; Li, Yong Qing; Lei, Liqing

1999-05-01

131

Strain-related variation in the persistence of influenza A virus in three types of water: distilled water, filtered surface water, and intact surface water  

PubMed Central

Background The persistence of influenza A (IA) virus in aquatic habitats has been demonstrated to be a determinant for virus transmission dynamics in wild duck populations. In this study, we investigated virus strain-related variation in persistence in water for nine wild duck isolated IA viruses of three subtypes (H3N8, H4N6, and H8N4). Results We experimentally estimated the loss of infectivity over time in three different types of water: distilled, filtered surface water, and intact surface water. All viruses persisted longest in distilled water followed by filtered surface water with markedly reduced durations of persistence observed in the intact surface water. Strain-related variations were observed in distilled and filtered surface water but limited variation was observed in the intact surface water. Conclusions Our findings suggest that the role of surface water for long-term (between years) maintenance of AI viruses in the environment may be limited, and suggest that the physico-chemical characteristics of water, as well as microorganisms, may be of strong importance. Results also indicate that the extent of strain-related variation observed in distilled water may overestimate persistence abilities for IA viruses in the wild and supports the need to develop experiments that account for these effects to assess subtype, genotype, as well as spatial and temporal variation in the persistence of IA viruses in aquatic habitats.

2013-01-01

132

Rupture and dewetting of water films on solid surfaces  

Microsoft Academic Search

An experimental study was conducted to observe rupture and dewetting of water films, 0.5–2mm thick, on solid surfaces. The effects of surface roughness, wettability, protrusions on surfaces, and air entrapment between films and surfaces were studied. Film thickness measurements were made and film rupture and surface dewetting photographed. Experiments showed that liquid films ruptured first along the highest edges of

Neil Mulji; Sanjeev Chandra

2010-01-01

133

Photochemical Transformation Processes in Sunlit Surface Waters  

NASA Astrophysics Data System (ADS)

Photochemical reactions are major processes in the transformation of hardly biodegradable xenobiotics in surface waters. They are usually classified into direct photolysis and indirect or sensitised degradation. Direct photolysis requires xenobiotic compounds to absorb sunlight, and to get transformed as a consequence. Sensitised transformation involves reaction with transient species (e.g. °OH, CO3-°, 1O2 and triplet states of chromophoric dissolved organic matter, 3CDOM*), photogenerated by so-called photosensitisers (nitrate, nitrite and CDOM). CDOM is a major photosensitiser: is it on average the main source of °OH (and of CO3-° as a consequence, which is mainly produced upon oxidation by °OH of carbonate and bicarbonate) and the only important source of 1O2 and 3CDOM* [1, 2]. CDOM origin plays a key role in sensitised processes: allochthonous CDOM derived from soil runoff and rich in fulvic and humic substances is usually more photoactive than autochthonous CDOM (produced by in-water biological processes and mainly consisting of protein-like material) or of CDOM derived from atmospheric deposition. An interesting gradual evolution of CDOM origin and photochemistry can be found in mountain lakes across the treeline, which afford a gradual transition of allochthonous- autochtonous - atmopheric CDOM when passing from trees to alpine meadows to exposed rocks [3]. Another important issue is the sites of reactive species photoproduction in CDOM. While there is evidence that smaller molecular weight fractions are more photoactive, some studies have reported considerable 1O2 reactivity in CDOM hydrophobic sites and inside particles [4]. We have recently addressed the problem and found that dissolved species in standard humic acids (hydrodynamic diameter < 0.1 ?m) account for the vast majority of 1O2 and triplet states photoproduction. In hydrophobic sites of particles, the formation rate of 1O2 is considerably lower than in the solution bulk [5], but the absence of water can significantly increase 1O2 half-life time (the main deactivation process of 1O2 in solution is collision with the solvent), thereby affording considerable reactivity toward hydrophobic solutes. The current knowledge in the field of natural photosensitizers in surface waters allows photoinduced transformation processes of organic pollutants to be assessed and modelled. For instance, it is possible to predict pollutant half-life times by knowing absorption spectrum, direct photolysis quantum yield and reaction rate constants with °OH, CO3-°, 1O2 and 3CDOM*, as a function of sunlight irradiance, water chemical composition (also affecting absorption) and column depth. Some examples of model application to real cases will be presented [6-8]. [1] Halladja et al., Environ Sci Technol 41, 6066 (2007) [2] Canonica et al., Environ Sci Technol 39, 9182 (2005) [3] De Laurentiis et al., Chemosphere 88, 1208 (2012) [4] Latch & McNeill, Science 311, 1743 (2006) [5] Minella et al., Chemosphere, accepted [6] Vione et al., Wat Res 45, 6725 (2011) [7] Sur et al., Sci Total Environ 426, 296 (2012) [8] De Laurentiis et al., Environ Sci Technol, DOI 10.1012/es3015887

Vione, D.

2012-12-01

134

Adsorption structure of water molecules on the Be(0001) surface  

NASA Astrophysics Data System (ADS)

By using density functional theory calculations, we systematically investigate the adsorption of water molecules at different coverages on the Be(0001) surface. The coverage dependence of the prototype water structures and energetics for water adlayer growth are systematically studied. The structures, energetics, and electronic properties are calculated and compared with other available studies. Through our systematic investigations, we find that water molecules form clusters or chains on the Be(0001) surface at low coverages. When increasing the water coverage, water molecules tend to form a 2 × 2 hexagonal network on the Be(0001) surface.

Yang, Yu; Li, Yanfang; Wang, Shuangxi; Zhang, Ping

2014-06-01

135

Effects of sublethal chronic copper exposure on the growth and reproductive success of the Florida apple snail (Pomacea paludosa).  

PubMed

Florida apple snails (Pomacea paludosa) were exposed to three concentrations of copper (Cu), in water (8 microg/L, 16 microg/L, 24 microg/L), for one generation to examine uptake and the effects on survival, growth, and reproduction of the F(0) generation and survival, growth, and whole body Cu of the F(1) generation. During a 9-month Cu exposure, apple snails exposed to 8-16 microg/L Cu had high Cu accumulation (whole body, foot, viscera, and shell) and significantly reduced clutch production (8-16 microg/L) and egg hatching (16 microg/L). Apple snails exposed to the 24 microg/L Cu had low survival and the treatment was therefore terminated. Concentrations of minerals (Na(+), K(+), Mg(2+), Ca(2+)) in tissues were maintained regardless of Cu exposure, but the distribution of Cu in the body of snails differed, depending on exposure concentrations. Higher exposure concentrations resulted in a greater percentage of Cu accumulated in the viscera of the snail. Copper exposure to the F(0) generation did not affect the survival, growth, or whole body Cu concentrations in the F(1) generation. These finding are significant, given the importance of the Florida apple snail in the Everglades food chain. Changes in the abundance of apple snail populations, as a result of Cu exposure, could ultimately affect foraging success of predators. PMID:18846313

Rogevich, Emily C; Hoang, Tham C; Rand, Gary M

2009-04-01

136

[Equipment for biological experiments with snails aboard piloted orbital stations].  

PubMed

To fly biological experiments aboard piloted orbital stations, research equipment was built up of an incubation container, filter system and automatic temperature controller. Investigations included analysis of the makeup and concentrations of gases produced by animals (snails) during biocycle, and emitted after death. Filters are chemisorption active fibrous materials (AFM) with high sorption rate and water receptivity (cation exchange fiber VION-KN-1 and anion exchange fiber VION-AS-1), and water-repellent carbon adsorbent SKLTS. AFM filters were effective in air cleaning and practically excluded ingress of chemical substances from the container into cabin atmosphere over more than 100 days. PMID:21033402

Gorgiladze, G I; Korotkova, E V; Kuznetsova, E E; Mukhamedieva, L N; Begrov, V V; Pepeliaev, Iu V

2010-01-01

137

Distribution of trematodes in snails in ponds at integrated small-scale aquaculture farms.  

PubMed

In integrated small-scale aquaculture farming, animal and human excreta maybe used as fish feed and pond fertilizer, thereby enhancing transmission of fish-borne zoonotic trematodes (FZTs) from final hosts, like humans, pigs and chickens, to snails. Areas within a pond could vary in trematode egg-load due to the immediate bordering land, and this might provide implications for control of these trematodes or sampling in field studies measuring FZT prevalence in snails. We therefore estimated the effect of bordering land use on prevalence and FZT burden in snails in different areas within small-scale aquaculture ponds. Nine sampling areas within a pond were assigned in six ponds. For each sampling area, about 120 Melanoides tuberculata snails were collected. Based on land use bordering a sampling area, these were categorized in 5 risk-categories: low-risk (road, rice planted in pond, agriculture, or middle of pond), human access point to pond, livestock sty (pigs or poultry), both human access point and livestock sty, and water connection to canal. In total, 5392 snails were collected. Percentages of snails with parapleurolophocercous cercariae varied between 6% in areas categorized as low-risk and areas with livestock sty only to 15% in areas with both human access point and livestock sty; only this 15% was significantly different from the prevalence in the low-risk category. Percentages of snails with xiphidio cercariae did not differ between risk-categories and varied between 5% and 10%. Mean snail size was 15.2mm, and was significantly associated with both the probability of infection as well as parasite burden. Very small differences in parasite burden were found at different land use areas; the maximum difference was about 11 cercariae. This study demonstrated only small differences between areas surrounding a pond on risk of snails to be infected with fish-borne trematodes within different pond areas. In field studies on FZTs in M. tuberculata snails in ponds, sampling from ponds can therefore be done without considering areas within ponds. PMID:23200642

Boerlage, Annette S; Graat, Elisabeth A M; Verreth, Johan A; de Jong, Mart C M

2013-03-01

138

The effects of endosulfan on the great ramshorn snail Planorbarius corneus (Gastropoda, Pulmonata): a histopathological study.  

PubMed

In this study the great ramshorn snail (Planorbarius corneus), one of the most abundant gastropod of Turkish limnic systems, was investigated to determine the histopathological effects of endosulfan on the digestive gland, foot and mantle under laboratory conditions. Samples were collected from small artificial pools in Karaot at Gelendost-Isparta (southwest of Turkey), where agricultural activities are widespread. The snails were exposed to two sublethal concentrations of endosulfan (0.4 and 0.8 mg/l) for periods of 10, 20 and 30 days. Fifteen snails were kept in 2.5 l glass jars containing dechlorinated tap water and exposed under semi-static test (daily exchange of test water). All the testing was carried out on adult specimens, and snails were maintained on a photothermal period with 16 light hours at 22 +/- 2 degrees C. The histopathological examinations revealed the following changes: amoebocytes infiltration, dilatation in hemolymphatic spaces between the tubules, degeneration of cells, abnormal lumen, necrosis of cells and atrophy in the connective tissue of digestive gland; desquamation of the epithelium cells, changes in the number of mucocytes and protein gland cells, lipid vacuolus and atrophy of the columnar muscle fibers of the foot and mantle tissues. Pycnotic state of cells was also seen in the mantle tissues. Endosulfan caused significant histopathological alterations in the digestive gland, foot and mantle tissues of the snail, irrespective of concentrations of the pesticide and its exposure periods. The results are discussed, particularly in comparison to those of other aquatic organisms. PMID:15234168

Otludil, Birgül; Cengiz, Elif Ipek; Yildirim, M Zeki; Unver, Ozkan; Unlü, Erhan

2004-08-01

139

How Water Meets a Hydrophobic Surface  

Microsoft Academic Search

Synchrotron x-ray reflectivity measurements of the interface between water and methyl-terminated octadecylsilane monolayers with stable contact angle >100° conclusively show a depletion layer, whether or not the water is degassed. The thickness is of order one water molecule: 2 4 Å with electron density <40% that of bulk water. Considerations of coherent and incoherent averaging of lateral inhomogeneities show that

Adelé Poynor; Liang Hong; Ian K. Robinson; Steve Granick; Zhan Zhang; Paul A. Fenter

2006-01-01

140

Simulation of Gas Compressible Flow by Free Surface Water Flow.  

National Technical Information Service (NTIS)

The analogy between the water flow with a free surface and the compressible fluid flow, commonly called hydraulic analogy, is analyzed and its limitations are identified. The water table is the equipment used for this simulation, which allows the quatitat...

C. R. Altafini R. T. da Silva Ferreira

1981-01-01

141

SURFACE WATER MONITORING SYSTEM INSTALLED ON BOARD THE ICEBREAKER SHIRASE  

Microsoft Academic Search

A surface water monitoring system was designed and installed on board the icebreaker SHIRASE. The system consists of sensors unit, navigation information terminal and control unit. Water pumped up from an intake of hull (8 m depth) is led into the sensors unit so as to measure flow rate of water, water temperature, conductivity, dissolved oxygen, fluorescence intensity, size com

Mitsuo FUKUCHI; Hiroshi HATTORI

142

77 FR 12227 - Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public...  

Federal Register 2010, 2011, 2012, 2013

...FRL-9641-3] Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public Meeting AGENCY: Environmental...the regulatory review of the uncovered finished water reservoir requirement in the Long Term 2...

2012-02-29

143

Freshwater snail consumption and angiostrongyliasis in Malaya.  

PubMed

A survey of the freshwater snails, Pila scutata and Bellamyia ingallsiana, as food consumed by the local population was carried out in Peninsular Malaysia. Of these two species the first is preferred; the sizes favoured are between 25--40 mm. Pila snails were found to be consumed by the three communities, viz. Malay, Chinese and Indian, in different ways. The various methods of preparing the snails for consumption are described. P. scutata is an intermediate host of the rat-lung worm, Angiostrongylus malaysiensis. As this worm presumably is the causative agent of human eosinophilic meningoencephalitis, the eating habits of the three races in consuming the snail in relation to the epidemiology of the disease was also discussed. PMID:726037

Liat, L B; Fong, Y L; Krishnansamy, M; Ramachandran, P; Mansor, S

1978-06-01

144

Surface tension of tactic polyvinylalcohols in water-DMSO-solution  

Microsoft Academic Search

Summary Surface tension of solutions of syndio-, iso- and atactic polyvinylalcohols in water-dimethylsulfoxide have been measured. Syndiotactic PVA is surface active with short relaxation time, nucleation and growth of the surface chains is rate determining. Isotactic surface adsorption is controlled by uncoiling of the intramolecular bonded sidegroups. If tactic PVA's have almost the same tactic percentage, tactic sequence distribution is

S. Matsuzawa; K. Ueberreiter

1978-01-01

145

COMBINED USE OF SURFACE AND GROUND WATER FOR THE WATER SUPPLY TO BARCELONA (SPAIN)  

Microsoft Academic Search

The geological and hydrological caracteristics of the ground-water reservoirs used for the Barcelona water suply are described. The conection between surface and ground water is emphasized.Ground water meets about 50% of the courrent water demands for water suply to Barcelona Metropolitan area (500 hm for year or 360 MGD).Present and future problems such as water pollution and water shortage, legal

M. R. LLAMAS

1969-01-01

146

Epigenetic regulation of EMT: the Snail story.  

PubMed

While the epithelial-mesenchymal transition (EMT) plays a fundamental role during development, its deregulation can adversely promote tumor metastasis. The phenotypic and cellular plasticity of EMT indicates that it is subject to epigenetic regulation. A hallmark of EMT is E-cadherin suppression. In this review, we try to embrace recent findings on the transcription factor Snail-mediated epigenetic silencing of E-cadherin. Our studies as well as those of others independently demonstrated that Snail can recruit various epigenetic machineries to the E-cadherin promoter. Based on these results, we propose a model of epigenetic regulation of EMT governed by Snail. Briefly, recruitment of the LSD1/HDAC complex by Snail facilitates histone H3K4 demethylation and H3/H4 deacetylation. Histone deacetylation may promote subsequent recruitment of PRC2 to methylate H3K27, while H3K4 demethylation favors the association of H3K9 methyltransferases G9a and Suv39H1. Finally, DNA methyltransferases (DNMTs) can be recruited to the promoter area in a G9a/Suv39H1-dependent manner. Together, these chromatin-modifying enzymes function in a Snail-mediated, highly orchestrated fashion to suppress E-cadherin. Disruption of the connection between Snail and these epigenetic machineries may represent an efficient strategy for the treatment of EMT-related diseases, including tumor metastasis. PMID:23888971

Lin, Yiwei; Dong, Chenfang; Zhou, Binhua P

2014-01-01

147

The role of Snail in prostate cancer  

PubMed Central

Prostate cancer is the second most frequently diagnosed cancer and the sixth leading cause of death from cancer in men. Epithelial-mesenchymal transition (EMT) is a process by which cancer cells invade and migrate, and is characterized by loss of cell-cell adhesion molecules such as E-cadherin and increased expression of mesenchymal proteins such as vimentin; EMT is also associated with resistance to therapy. Snail, a master regulator of EMT, has been extensively studied and reported in cancers such as breast and colon; however, its role in prostate cancer is not as widely reported. The purpose of this review is to put together recent facts that summarize Snail signaling in human prostate cancer. Snail is overexpressed in prostate cancer and its expression and activity is controlled via phosphorylation and growth factor signaling. Snail is involved in its canonical role of inducing EMT in prostate cancer cells; however, it plays a role in non-canonical pathways that do not involve EMT such regulation of bone turnover and neuroendocrine differentiation. Thus, studies indicate that Snail signaling contributes to prostate cancer progression and metastasis and therapeutic targeting of Snail in prostate cancer holds promise in ?future.

Smith, Bethany N.; Odero-Marah, Valerie A.

2012-01-01

148

Spreading of Cholera through Surface Water  

NASA Astrophysics Data System (ADS)

Cholera epidemics are still a major public health concern to date in many areas of the world. In order to understand and forecast cholera outbreaks, one of the most important factors is the role played by the environmental matrix in which the disease spreads. We study how river networks, acting as environmental corridors for pathogens, affect the spreading of cholera epidemics. The environmental matrix in which the disease spreads is constituted by different human communities and their hydrologic interconnections. Each community is characterized by its spatial position, population size, water resources availability and hygiene conditions. By implementing a spatially explicit cholera model we seek the effects on epidemic dynamics of: i) the topology and metrics of the pathogens pathways that connect different communities; ii) the spatial distribution of the population size; and iii) the spatial distributions and quality of surface water resources and public health conditions, and how they vary with population size. The model has been applied to study the space-time evolution of a well documented cholera epidemic occurred in the KwaZulu-Natal province of South Africa. The epidemic lasted for two years and involved about 140,000 confirmed cholera cases. The model does well in reproducing the distribution of the cholera cases during the two outbreaks as well as their spatial spreading. We further extend the model by deriving the speed of propagation of traveling fronts in the case of uniformly distributed systems for different topologies: one and two dimensional lattices and river networks. The derivation of the spreading celerity proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. The conditions are sought by comparison between spreading and disease timescales. Consider a cholera epidemic that starts from a point and spreads throughout a finite size system, it is possible to identify two different timescales: i) the spreading timescale, that is the time needed for the disease to spread and involve all the communities in the system; and ii) the epidemic timescale, defined by the duration of the epidemic in a single community. Our results suggest that in many cases of real-life epidemiological interest, timescales of disease dynamics may trigger outbreaks that significantly depart from the predictions of classical space-implicit compartmental models.

Bertuzzo, E.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

2009-12-01

149

Surface Tension: The Ways of Water.  

ERIC Educational Resources Information Center

Describes activities which help students understand several basic scientific concepts regarding water. Outlines objectives, materials needed, procedures, and questions to ask about student observations. Investigations include working with the self-sealing property of water, talcum powder, paper clips, and making water wetter. (RT)

Donalson-Sams, Marilyn

1988-01-01

150

Electrostatic painting of nonconductive surfaces with water-base paints  

SciTech Connect

Electrostatic corona painting on nonconductive surfaces normally requires a ground-connected conductive precoating of the surface in order to dissipate the continuously incoming ionic charge from the corona gun. If the surface charge does not flow to ground, the resulting surface electric field will repel a substantial amount of the incoming paint. The authors present a new painting method consisting of generating ultrasonically atomized electrically charged water particles behind the nonconductive surface to be painted. The paint spraying is carried out with a mechanical spray gun maintained at ground potential. The water base paint becomes charged by induction under the influence of the space charge behind the nonconductive surface to be painted. As the resulting charge on the water base paint particles is of opposite polarity to that of the ultrasonically atomized electrically charged water particles cloud, all propelling electric fields converge toward the surface to be painted. The results show excellent transfer efficiencies.

Inculet, I.I. [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering] [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering; Klein, R.G. [Nordson Corp., Westlake, OH (United States)] [Nordson Corp., Westlake, OH (United States)

1996-01-01

151

Has Surface Water Quality Improved Since the Clean Water Act?  

Microsoft Academic Search

On the fortieth anniversary of the Clean Water Act this paper reports the first quantitative assessment of the aggregate trends in water quality in the U.S. using a single standard over the years 1975 to 2011. The analysis suggests that fresh water lakes for the nation as a whole are about at the same quality levels as they were in

V. Kerry Smith; Carlos Valcarcel Wolloh

2012-01-01

152

New Pest Response Guidelines: Giant African Snails: Snail Pests in the Family Achatinidae.  

National Technical Information Service (NTIS)

Use New Pest Response Guidelines. Giant African Snails: Snail Pests in the Family Achatinidae as a guide when designing a program to detect, monitor, control, contain, or eradicate an infestation of achatinids. If these pests are detected in the United St...

2007-01-01

153

Molecular dynamics studies of interfacial water at the alumina surface.  

SciTech Connect

Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.

Argyris, Dr. Dimitrios [University of Oklahoma; Ho, Thomas [ORNL; Cole, David [Ohio State University

2011-01-01

154

Heat shock proteins and survival strategies in congeneric land snails (Sphincterochila) from different habitats.  

PubMed

Polmunate land snails are subject to stress conditions in their terrestrial habitat, and depend on a range of behavioural, physiological and biochemical adaptations for coping with problems of maintaining water, ionic and thermal balance. The involvement of the heat shock protein (HSP) machinery in land snails was demonstrated following short-term experimental aestivation and heat stress, suggesting that land snails use HSPs as part of their survival strategy. As climatic variation was found to be associated with HSP expression, we tested whether adaptation of land snails to different habitats affects HSP expression in two closely related Sphincterochila snail species, a desert species Sphincterochila zonata and a Mediterranean-type species Sphincterochila cariosa. Our study suggests that Sphincterochila species use HSPs as part of their survival strategy following desiccation and heat stress, and as part of the natural annual cycle of activity and aestivation. Our studies also indicate that adaptation to different habitats results in the development of distinct strategies of HSP expression in response to stress, namely the reduced expression of HSPs in the desert-inhabiting species. We suggest that these different strategies reflect the difference in heat and aridity encountered in the natural habitats, and that the desert species S. zonata relies on mechanisms and adaptations other than HSP induction thus avoiding the fitness consequences of continuous HSP upregulation. PMID:22528052

Mizrahi, Tal; Heller, Joseph; Goldenberg, Shoshana; Arad, Zeev

2012-09-01

155

A surface acoustic wave sensor study of polyimide thin film surface treatments - effect on water uptake  

Microsoft Academic Search

The effects of surface treatments on the water uptake in thin (1 ?m) polyimide (PI) films were studied using a surface acoustic wave (SAW) sensor, X-ray photoelectron spectroscopy (XPS), external reflectance infrared (ERIR) spectroscopy, and contact angle measurements. Surface modification of PI films can affect film properties such as water uptake and adhesion. These properties, in turn, affect the performance

D. W. Galipeau; P. R. Story; C. Feger; K.-W. Lee

1994-01-01

156

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited  

SciTech Connect

Water is perhaps the most important and most pervasive chemical on our planet. The influence of water permeates virtually all areas of biochemical, chemical and physical importance, and is especially evident in phenomena occurring at the interfaces of solid surfaces. Since 1987, when Thiel and Madey (TM) published their review titled "The Interaction of Water with Solid Surfaces: Fundamental Aspects" in Surface Science Reports, there has been considerable progress made in further understanding the fundamental interactions of water with solid surfaces. In the decade and a half, the increased capability of surface scientists to probe at the molecular-level has resulted in more detailed information of the properties of water on progressively more complicated materials and under more stringent conditions. This progress in understanding the properties of water on solid surfaces is evident both in areas for which surface science methodology has traditionally been strong (catalysis and electronic materials) and also in new areas not traditionally studied by surface scientists, such as electrochemistry, photoconversion, mineralogy, adhesion, sensors, atmospheric chemistry, and tribology. Researchers in all these fields grapple with very basic questions regarding the interactions of water with solid surfaces, such as how is water adsorbed, what are the chemical and electrostatic forces that constitute the adsorbed layer, how is water thermally or non-thermally activated, and how do coadsorbates influence these properties of water. The attention paid to these and other fundamental questions in the past decade and a half has been immense. In this review, experimental studies published since the TM review are assimilated with those covered by TM to provide a current picture of the fundamental interactions of water with solid surfaces.

Henderson, Michael A.

2002-05-01

157

The interaction of water with solid surfaces: fundamental aspects revisited  

NASA Astrophysics Data System (ADS)

Water is perhaps the most important and most pervasive chemical on our planet. The influence of water permeates virtually all areas of biochemical, chemical and physical importance, and is especially evident in phenomena occurring at the interfaces of solid surfaces. Since 1987, when Thiel and Madey (TM) published their review titled 'The interaction of water with solid surfaces: fundamental aspects' in Surface Science Reports, there has been considerable progress made in further understanding the fundamental interactions of water with solid surfaces. In the decade and a half, the increased capability of surface scientists to probe at the molecular-level has resulted in more detailed information of the properties of water on progressively more complicated materials and under more stringent conditions. This progress in understanding the properties of water on solid surfaces is evident both in areas for which surface science methodology has traditionally been strong (catalysis and electronic materials) and also in new areas not traditionally studied by surface scientists such as electrochemistry, photoconversion, mineralogy, adhesion, sensors, atmospheric chemistry and tribology. Researchers in all these fields grapple with very basic questions regarding the interactions of water with solid surfaces such as how is water adsorbed, what are the chemical and electrostatic forces that constitute the adsorbed layer, how is water thermally or non-thermally activated and how do coadsorbates influence these properties of water. The attention paid to these and other fundamental questions in the past decade and a half has been immense. In this review, experimental studies published since the TM review are assimilated with those covered by TM to provide a current picture of the fundamental interactions of water with solid surfaces.

Henderson, Michael A.

2002-05-01

158

Behavioural responses of the snail Lymnaea acuminata to carbohydrates in snail-attractant pellets  

NASA Astrophysics Data System (ADS)

Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.

Tiwari, Farindra; Singh, D. K.

159

Salinity adaptation of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in the Columbia River estuary (Pacific Northwest, USA): physiological and molecular studies  

USGS Publications Warehouse

In this study, we examine salinity stress tolerances of two populations of the invasive species New Zealand mud snail Potamopyrgus antipodarum, one population from a high salinity environment in the Columbia River estuary and the other from a fresh water lake. In 1996, New Zealand mud snails were discovered in the tidal reaches of the Columbia River estuary that is routinely exposed to salinity at near full seawater concentrations. In contrast, in their native habitat and throughout its spread in the western US, New Zealand mud snails are found only in fresh water ecosystems. Our aim was to determine whether the Columbia River snails have become salt water adapted. Using a modification of the standard amphipod sediment toxicity test, salinity tolerance was tested using a range of concentrations up to undiluted seawater, and the snails were sampled for mortality at daily time points. Our results show that the Columbia River snails were more tolerant of acute salinity stress with the LC50 values averaging 38 and 22 Practical Salinity Units for the Columbia River and freshwater snails, respectively. DNA sequence analysis and morphological comparisons of individuals representing each population indicate that they were all P. antipodarum. These results suggest that this species is salt water adaptable and in addition, this investigation helps elucidate the potential of this aquatic invasive organism to adapt to adverse environmental conditions.

Hoy, Marshal; Boese, Bruce L.; Taylor, Louise; Reusser, Deborah; Rodriguez, Rusty

2012-01-01

160

The need for satellite based observations of global surface waters  

Microsoft Academic Search

River discharge as well as lake and wetland storage of water are critical elements of land surface hydrology, yet they are poorly observed globally and the prospects for improvement from in-situ networks are bleak. Considering this, our NASA Surface Water working group is focused on the following science and applications questions: (1) What are the observational and data assimilation requirements

D. Lettenmaier; D. Alsdorf; C. Vörösmarty; C. Birkett

2003-01-01

161

Evaluation of surface water quality impacts of hazardous chemical sites  

Microsoft Academic Search

SUMMARY Common deficiencies in the typical evaluation of the surface water quality impacts of hazardous chemical sites are discussed. Particular attention is given to deficiencies in monitoring stormwater runoff, as well as the input of contaminated groundwaters that lead to impairment of the beneficial uses of nearby surface waters due to site-derived hazardous and deleterious chemicals. An alternative approach, Evaluation

G. Fred Lee; Anne Jones-Lee

1999-01-01

162

Surface water characteristics in NCEP global spectral model and reanalysis  

Microsoft Academic Search

Characteristics of the National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP\\/NCAR) reanalysis surface water budget are compared to the surface water budget characteristics in a long-term simulation with the NCEP global spectral model (GSM) used in the reanalysis. There are many geographic similarities. There are a few differences though, mainly because the reanalysis has a source

J. O. Roads; S.-C. Chen; M. Kanamitsu; H. Juang

1999-01-01

163

Rinsing effect of alkaline electrolyzed water on nickel surfaces  

Microsoft Academic Search

The improvement in the surface cleanliness of electroplated nickel by rinsing in alkaline electrolyzed water (AEW) was determined. When the nickel plated sample was rinsed with the AEW, it was found that the amount of residual sulfate ion on the surface of a sample decreased approximately by half compared to one rinsed only with de-ionized pure water. Because nanosize hydrogen

Toshikazu Takenouchi; Shin-ichi Wakabayashi

2006-01-01

164

Automated detection of surface defects in water and sewer pipes  

Microsoft Academic Search

Automation is gaining momentum in industry, particularly in rehabilitation and inspection works of underground infrastructure facilities. This paper describes a model for automating inspection and identification of surface defects in underground water and sewer pipes. The paper describes the current efforts in identification of surface defects in underground water and sewer mains, and presents an automated system designed to assist

Osama Moselhi; Tariq Shehab-Eldeen

1999-01-01

165

TOTAL ALKALINITY OF SURFACE WATERS OF THE US  

EPA Science Inventory

This map provides a synoptic illustration of the national patterns of surface water alkalinity in the conterminous United States. Alkalinity is the most readily available measure of the acid-neutralizing capacity of surface waters and provides a reasonable estimate o...

166

PROTECTING SURFACE WATER SYSTEMS ON FOREST SITES THROUGH HERBICIDE USE  

Microsoft Academic Search

Sediment, nutrients, and pesticides are universally accepted as the greatest threats to surface water quality world-wide. Sedimentation in surface waters is a natural phenomenon, but is magnified by human activities. Intensive forest management practices, particularly road building, harvesting and planting site preparation, result in the greatest increases in erosion from forest sites. Significantly more sedimentation occurs on steeper slopes, finer-textured

J. L. Michael; H. L. Gibbs; J. B. Fischer; E. C. Webber

167

Dynamic behavior of interfacila water at the silica surface  

SciTech Connect

Molecular dynamics simulations were employed to study the dynamics properties of water at the silica-liquid interface at ambient temperature. Three different degrees of hydroxylation of a crystalline silica surface were used. To assess the water dynamic properties we calculated the residence probability and in-plane mean square displacement as a function of distance from the surface. The data indicate that water molecules at the fully hydroxylated surface remain longer, on average, in the interfacial region than in the other cases. By assessing the dynamics of molecular dipole moment and hydrogen-hydrogen vector an anisotropic reorientation was discovered for interfacial water in contact with any of the surfaces considered. However, the features of the anisotropic reorientation observed for water molecules depend strongly on the relative orientation of interfacial water molecules and their interactions with surface hydroxyl groups. On the partially hydroxylated surface, where water molecules with hydrogen-down and hydrogen-up orientation are both found, those water molecules associated with surface hydroxyl groups remain at the adsorbed locations longer and reorient slower than the other water molecules. A number of equilibrium properties, including density profiles, hydrogen bond networks, charge densities, and dipole moment densities are also reported to explain the dynamics results.

Argyris, Dr. Dimitrios [University of Oklahoma; Cole, David R [ORNL; Striolo, Alberto [Oklahoma University

2009-01-01

168

Sea-ice and surface water circulation, Alaskan continental shelf  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Over 1500 water samples from surface and from standard hydrographic depths were collected during June and July 1973 from Bering Sea and Gulf of Alaska. The measurement of temperature, salinity, and productivity indicated that various distinct water masses cover the Bering Sea Shelf. The suspended load in surface waters will be correlated with the ERTS-1 imagery as it becomes available to delineate the surface water circulation. The movement of ice floes in the Bering Strait and Bering Sea indicated that movement of ice varies considerably and may depend on wind stress as well as ocean currents.

Wright, F. F.; Sharma, G. D.; Burns, J. J. (principal investigators)

1973-01-01

169

The ecology of vector snail habitats and mosquito breeding-places  

PubMed Central

The ecology of freshwater snails—in particular those which act as intermediate hosts of bilharziasis—is reviewed in the light of the much more extensive knowledge available on the breeding-places of anopheline mosquitos. Experimental ecological methods are recommended for the field and laboratory investigation of a number of common problems involved in the study of snail habitats and mosquito breeding-places. Among the environmental factors discussed are temperature, oxygen concentration, water movement, pollution and salinity. Sampling methods for estimating populations of both snails and mosquito larvae are also described. An attempt is made to show how malacologists and entomologists alike would benefit from improved facilities for keeping abreast of general developments in the wider field of freshwater ecology.

Muirhead-Thomson, R. C.

1958-01-01

170

Herbicide Metabolites in Surface Water and Groundwater: Introduction and Overview  

USGS Publications Warehouse

Several future research topics for herbicide metabolites in surface and ground water are outlined in this chapter. They are herbicide usage, chemical analysis of metabolites, and fate and transport of metabolites in surface and ground water. These three ideas follow the themes in this book, which are the summary of a symposium of the American Chemical Society on herbicide metabolites in surface and ground water. First, geographic information systems allow the spatial distribution of herbicide-use data to be combined with geochemical information on fate and transport of herbicides. Next these two types of information are useful in predicting the kinds of metabolites present and their probable distribution in surface and ground water. Finally, methods development efforts may be focused on these specific target analytes. This chapter discusses these three concepts and provides an introduction to this book on the analysis, chemistry, and fate and transport of herbicide metabolites in surface and ground water.

Thurman, E. M.; Meyer, M. T.

1996-01-01

171

Surface-Water Quality-Assurance Plan for the USGS Wisconsin Water Science Center  

USGS Publications Warehouse

This surface-water quality-assurance plan documents the standards, policies, and procedures used by the Wisconsin Water Science Center of the U.S. Geological Survey, Water Resources Discipline, for activities related to the collection, processing, storage, analysis, management, and publication of surface-water data. The roles and responsibilities of Water Science Center personnel in following these policies and procedures including those related to safety and training are presented.

Garn, H. S.

2007-01-01

172

Enhanced ordering of water at hydrophobic surfaces  

NASA Astrophysics Data System (ADS)

We study the properties of water molecules adjacent to a hydrophobic molecular layer with vibrational sum-frequency generation spectroscopy. We find that the water molecules at D2O/hexane, D2O/heptane, and D2O/polydimethylsiloxane interfaces show an enhanced ordering and stronger hydrogen-bond interactions than the water molecules at a D2O/air interface. With increasing temperature (up to 80 °C) the water structure becomes significantly less ordered and the hydrogen bonds become weaker.

Strazdaite, Simona; Versluis, Jan; Backus, Ellen H. G.; Bakker, Huib J.

2014-02-01

173

Enhanced ordering of water at hydrophobic surfaces.  

PubMed

We study the properties of water molecules adjacent to a hydrophobic molecular layer with vibrational sum-frequency generation spectroscopy. We find that the water molecules at D2O/hexane, D2O/heptane, and D2O/polydimethylsiloxane interfaces show an enhanced ordering and stronger hydrogen-bond interactions than the water molecules at a D2O/air interface. With increasing temperature (up to 80 °C) the water structure becomes significantly less ordered and the hydrogen bonds become weaker. PMID:24511972

Strazdaite, Simona; Versluis, Jan; Backus, Ellen H G; Bakker, Huib J

2014-02-01

174

How Water Meets a Hydrophobic Surface  

NASA Astrophysics Data System (ADS)

Synchrotron x-ray reflectivity measurements of the interface between water and methyl-terminated octadecylsilane monolayers with stable contact angle >100° conclusively show a depletion layer, whether or not the water is degassed. The thickness is of order one water molecule: 2 4 Å with electron density <40% that of bulk water. Considerations of coherent and incoherent averaging of lateral inhomogeneities show that the data cannot be explained by “nanobubbles.” When the contact angle is lower, unstable in time, or when monolayers fail to be sufficiently smooth over the footprint of the x-ray beam, there is no recognizable depletion.

Poynor, Adelé; Hong, Liang; Robinson, Ian K.; Granick, Steve; Zhang, Zhan; Fenter, Paul A.

2006-12-01

175

Electrical responses to amputation of the eye in the mystery snail.  

PubMed

Immediately following amputation through the eyestalk of the mystery snail (Pomacea), a persistent ionic current enters the apical amputation surface of the eyestalk stump. The circuit is completed by current driven from undamaged integument of the eyestalk stump and other body regions. The current is relatively steady during the first 10 hours following amputation. Currents subsequently begin a slow decline to base line levels by 60 hours postamputation--a time coincident with wound healing processes. The "battery" driving this ionic current is the internally negative transepidermal potential existing across the snail integument--perhaps the result of a net inward pumping of chloride across the skin. This system is compared to other regeneration models such as the amphibian limb, bone fracture repair, and skin wound healing. We suggest that ionic current may be a control of eye regeneration in the snail. PMID:3351444

Bever, M M; Borgens, R B

1988-01-01

176

Biogeochemistry of DMS in Surface Waters  

NASA Technical Reports Server (NTRS)

Dimethylsulfide (DMS) is important in influencing the formation of aerosols in the troposphere over large areas of the world's oceans. Understanding the dynamics of aerosols is important to understanding the earth's radiation balance. In evaluating the factors controlling DMS in the troposphere it is vital to understand the dynamics of DMS in the surface ocean. The biogeochemical processes controlling DMS concentration in seawater are myriad; modeling and theoretical estimation are problematic. At the beginning of this project we believed that we were on the verge of simplifying the ship-track measurement of DMS, and we proposed to deploy such a system to develop a database relating high frequency DMS measurements to biological and physicochemical and optical properties of surface water that can be quantified by remote sensing techniques. We designed a system to measure DMS concomitantly with other basic chemical and biological data in a flow-through system. The project was collaborative between Woods Hole Oceanographic Institution (WHOI) and Bermuda Biological Station for Research (BBSR). The project on which we are reporting was budgeted for only one year with a one year no-cost extension. At WHOI our effort was directed towards designing traps which would be used to concentrate DMS from seawater and allow storage for subsequent analysis. At that time, GC systems were too large for easy long-term deployment on a research vessel like R/V Weatherbird, so we focused on simplifying the shipboard sampling procedure. Initial studies of sample recovery with high levels of DMS suggested that Carboxen 1000, a relatively new carbon molecular sieve, could be used as a stable storage medium. The affinity of Carboxen for DMS is several orders of magnitude higher than gold wool (another adsorbent used for DMS collection) on a weight or volume basis. Furthermore, Carboxen's affinity for DMS is also far less susceptible to humidity than gold wool. Unfortunately, further experiments with low level DMS indicated that recovery of DMS after storage was not quantitative. The material has proven to be completely acceptable for short term storage and has been incorporated into a micro-GC system. Since working on this project, we have collaborated with RVM Scientific in Santa Barbara in the design and construction of small portable micro-GC's that will make feasible at-sea measurement in moving ships, making rapid gas analysis and quantification feasible in a ship-track mode. Throughout this period at both WHOI and BBSR, we continued to analyze field data to understand that patterns of time and space variability in DMS and the processes that govern it. These insights will be crucial to determining the specifications for our automated sampling program. The data from this, the longest continuous sampling program for ocean DMS, provided insights into year to year and short-term variability.

Dacey, J. W. H.

1997-01-01

177

Tribological properties of adsorbed water layer on silicon surfaces  

Microsoft Academic Search

Tribological properties of adsorbed water layer on solid surface in sliding contact have not yet been fully understood. In\\u000a this regard, it is important to better understand how surface hydrophilicity and humidity influence the tribological behavior\\u000a of adsorbed water-mediated microcontact. In this study, we investigated the influence of adsorbed water layer and capillary\\u000a force on friction as a function of

Doo-In Kim; Kwang-Ho Kim; Hyo-Sok Ahn

2010-01-01

178

Manure Phosphorus and Surface Water Protection III: Transport Factors  

NSDL National Science Digital Library

This lesson addresses transport factors that may contribute to phosphorus (P) delivery to surface waters.  Erosion, runoff, subsurface flow, drainage, and distance to surface water are the main factors.  In some places, wind erosion may also be important.  The effects of management practices on P transport are discussed, and water-related P transport processes are described in detail. 

179

SPATIAL AND TEMPORAL VARIABILITY IN NEST SUCCESS OF SNAIL KITES IN FLORIDA: A META-ANALYSIS  

Microsoft Academic Search

Nesting success of Snail Kites (Rostrhamus sociabilis) in Florida is highly variable among years and locations, and hydrology is the most frequently reported explan- atory factor. We conducted a meta-analysis to evaluate the extent of spatial and temporal variability in nesting success, and explicitly tested for the effects of annual minimum water levels. Data were obtained from six independent studies

Victoria J. Dreitz; Robert E. Bennetts; Brian Toland; Wiley M. Kitchens; Michael W. Collopy

2001-01-01

180

Management of land snails in cut green ornamentals by copper hydroxide formulations  

Microsoft Academic Search

The efficacy of copper hydroxide formulations in controlling land snails was tested on two plots of cut green ornamentals in shadehouses. One was a Ruscus hypoglossum plot that was infected and damaged by Monacha syriaca; the second was an Aspidistra elatior plot that was infected and damaged mainly by Theba pisana and M. syriaca. Two formulations of water dispersible granules

Shmuel Moran; Yaacov Gotlib; Benjamin Yaakov

2004-01-01

181

The effects of Bayluscid on gastropod snails and other Aquatic Fauna in Rhodesia  

Microsoft Academic Search

Extensive use of the molluscicide, Bayluscid (Bayer 73), in natural waters in Rhodesia led to fears that the aquatic fauna as a whole, including the predators of gastropod snails, would be adversely affected. The purpose of this study was to test the effects of one intensive application of Bayluscid on two stream catchments and in one small impoundment. The two

A. D. Harrison

1966-01-01

182

Coagulation of low turbidity surface waters with Moringa oleifera seeds  

Microsoft Academic Search

The use of Moringa oleifera seed extracts both as primary coagulant coagulant aid and its conjunctive use with alum in treating low turbidity waters was studied. The laboratory based studies used the natural polyelectrolyte to treat waters with turbidities between 23 and 90 ntu, obtained from three surface water sources in Kano, Nigeria. On the average, 50% turbidity removal was

Suleyman A. Muyibi; Charles A. Okuofu

1995-01-01

183

Animation and rendering of complex water surfaces  

Microsoft Academic Search

We present a new method for the animation and rendering of photo-realistic water effects. Our method is designed to produce visually plausible three dimensional effects, for example the pouring of water into a glass (see figure 1) and the breaking of an ocean wave, in a manner which can be used in a computer animation environment. In order to better

Douglas Enright; Stephen R. Marschner; Ronald Fedkiw

2002-01-01

184

Simulating continental surface waters: An application to Holocene northern Africa  

SciTech Connect

A model (SWAM) to predict surface waters (lakes and wetlands) on the scale of atmospheric general circulation models is developed. SWAM is based on a linear reservoir hydrologic model and is driven by runoff, precipitation, evaporation, topography, and water transport directions. SWAM is applied to the modern climate using observed estimates of the hydrologic variables and a 5{prime} {times} 5{prime} digital terrain model to represent topography. It simulates the surface water area of northern Africa (about 1% of the land area) in reasonable agreement with observed estimates (0.65%). A middle Holocene (6000 yr BP) simulation using the results of the GENESIS atmospheric general circulation model (AGCM) illustrates the sensitivity of the simulated surface waters to climatic changes and the model`s utility as a diagnostic tool for AGCMs. SWAM and GENESIS capture the general pattern of climate change 6000 yr BP. There is an increase in the simulated surface water area from about 1% to about 3% of the land area, including an increase in the area of Lake Chad by about five times and extensive surface water throughout northern Mali, consistent with observed patterns of surface water change during the Holocene. Limitations in the modeling of surface waters appear to result from the relatively coarse resolution of global elevation data. 73 refs., 6 figs., 2 tabs.

Coe, M.T. [Univ. of Wisconsin, Madison, WI (United States)] [Univ. of Wisconsin, Madison, WI (United States)

1997-07-01

185

Ionization of water clusters by collisions with graphite surfaces  

Microsoft Academic Search

We present experimental results on the scattering of neutral water clusters from graphite surfaces. We use cluster beams with an average cluster size up to 3700 molecules and an incident velocity of 1300 m\\/s, and study the emission of negatively and positively charged cluster fragments from the surface. The ionization probability is found to depend on cluster size and surface

P. U. Andersson; J. B. C. Pettersson

1997-01-01

186

SURFACE AND SUBSURFACE WATER QUALITY HYDROLOGY IN SURFACE MINED WATERSHEDS. PART I: TEXT  

EPA Science Inventory

Surface mining disturbs the natural sequence of geologic strata, and, therefore, potentially modifies the quantity and quality of water on a watershed disturbed by surface mining. Such a watershed disturbed by surface mining was monitored in Colorado. In addition, surface runoff,...

187

Reproduction and demography of the Florida Everglade (Snail) Kite  

USGS Publications Warehouse

An 18-year study of reproduction and survival of the Florida Everglade (Snail) Kite (Rostrhamus sociabilis plumbeus) has revealed the following: extremely poor nesting success (only 13.6% of nests found at the nest-building stage successful); extremely long breeding seasons (some reproductive activity in almost all months in good years); frequent multiple brooding and frequent multiple brooding and frequent renesting after failure; low egg hatchability (81%); high failure rates due to nest collapse, desertion, and predation; extremely high survival of juveniles and adults under good water conditions; and high vulnerability to drought due to near total dependency on a single species of drought-sensitive snail for food. Despite low nesting success, the species has increased rapidly under good conditions, mainly because of multiple nesting attempts within long breeding seasons and high survival rates of free-flying birds. Nesting success varied significantly between regions and nest substrates, but not as a function of seasons or solitary vs. colonial nesting. While nesting success was reduced in low water years, this effect was at least partly due to heavy use of poor nest substrates under such conditions. Clutch size and numbers of young per successful nest varied with regions, but not as a function of seasons or water levels. The effects of coloniality on clutch size and numbers of young were inconsistent. Significant effects of nest-substrate types on clutch size and numbers of young were apparently artifacts of substrate differences between regions.

Snyder, N.F.R.; Beissinger, S.R.; Chandler, R.E.

1989-01-01

188

Multivariate analyses of water chemistry: surface and ground water interactions.  

PubMed

Multivariate statistical methods (MSMs) applied to ground water chemistry provide valuable insight into the main hydrochemical species, hydrochemical processes, and water flowpaths important to ground water evolution. The MSMs of principal component factor analysis (FA) and k-means cluster analysis (CA) were sequentially applied to major ion chemistry from 211 different ground water-sampling locations in the Amargosa Desert. The FA reduces the number of variables describing the system and finds relationships between major ions. The CA of the reduced system produced objective hydrochemical facies, which are independent of, but in good agreement with, lithological data. The derived factors and hydrochemical facies are innovatively presented on biplots, revealing composition of hydrochemical processes and facies, and overlaid on a digital elevation model, displaying flowpaths and interactions with geologic and topographic features in the region. In particular, a distinct ground water chemical signature is observed beneath and surrounding the extended flowpath of Fortymile Wash, presenting some contradiction to contemporary water levels along with potential interaction with a fault line. The signature surrounding the ephemeral Fortymile Wash is believed to represent the relic of water that infiltrated during past pluvial periods when the amount of runoff in the wash was significantly larger than during the current drier period. This hypothesis and aforementioned analyses are supported by the examination of available chloride, oxygen-18, hydrogen-2, and carbon-14 data from the region. PMID:18194324

Woocay, Arturo; Walton, John

2008-01-01

189

Snail depletes the tumorigenic potential of glioblastoma  

PubMed Central

Glioblastoma multiforme (GBM) is an aggressive brain malignancy characterized by high heterogeneity and invasiveness. It is increasingly accepted that the refractory feature of GBM to current therapies stems from the existence of few tumorigenic cells that sustain tumor growth and spreading, the so-called glioma-initiating cells (GICs). Previous studies showed that cytokines of the bone morphogenetic protein (BMP) family induce differentiation of the GICs, and thus act as tumor suppressors. Molecular pathways that explain this behavior of BMP cytokines remain largely elusive. Here, we show that BMP signaling induces Smad-dependent expression of the transcriptional regulator Snail in a rapid and sustained manner. Consistent with its already established promigratory function in other cell types, we report that Snail silencing decreases GBM cell migration. Consequently, overexpression of Snail increases GBM invasiveness in a mouse xenograft model. Surprisingly, we found that Snail depletes the GBM capacity to form gliomaspheres in vitro and to grow tumors in vivo, both of which are important features shared by GICs. Thus Snail, acting downstream of BMP signaling, dissociates the invasive capacity of GBM cells from their tumorigenic potential.

Savary, K; Caglayan, D; Caja, L; Tzavlaki, K; Bin Nayeem, S; Bergstrom, T; Jiang, Y; Uhrbom, L; Forsberg-Nilsson, K; Westermark, B; Heldin, C-H; Ferletta, M; Moustakas, A

2013-01-01

190

Interfacial entropy of water on rigid hydrophobic surfaces.  

PubMed

A simple theoretical model is proposed for computing the interfacial entropy of water at rigid hydrophobic surfaces. The interfacial entropy, which is not considered in mean field models of static wettability, is evaluated from the fluctuations of the water-surface dispersion energy at the single particle level and represents the configurational bias imposed on the fluid molecules by the attractive external potential of a solid wall. A comparison with results obtained from molecular dynamics simulations shows that the model quantitatively describes the entropy loss of water when a water-vapor interface turns to water in contact with hydrophobic surfaces such as graphene, graphite, and diamond, while it overestimates this quantity on hydrophilic surfaces. PMID:23855801

Taherian, Fereshte; Leroy, Frédéric; van der Vegt, Nico F A

2013-08-01

191

Surface finishing of micro-EDM holes using deionized water  

NASA Astrophysics Data System (ADS)

In this paper, with the use of deionized water, a finishing process of micro hole surfaces processed by micro electrical discharge machining (micro-EDM) is investigated. A micro hole is machined by micro-EDM using deionized water as a dielectric fluid. The inner surface of the hole is finished successfully via electrochemical dissolution in deionized water. The effects of finishing conditions such as the resistivity of deionized water, the voltage, the tool rotation and the finishing time on the surface quality and accuracy of the shape were investigated. After a finishing process using deionized water with a resistivity of 2 M? cm, a voltage of 80 V, a tool rotation of 1200 rpm and a finishing time of 6 min, the surface roughness was reduced considerably from 0.225 µm Ra after micro-EDM to 0.066 µm Ra.

Chung, Do Kwan; Shin, Hong Shik; Kim, Bo Hyun; Park, Min Soo; Chu, Chong Nam

2009-04-01

192

Larval trematodes: double infections in common mud-flat snail.  

PubMed

Larvae of the trematode Zoogonus lasius are involved in most double infections of Nassarius obsoleta. The two most common trematode parasites of this snail do not occur together in double infections. Double infections were found in 14 of 340 infected snails in a total sample of 5025 snails. PMID:5770621

Vernberg, W B; Vernberg, F J; Beckerdite, F W

1969-06-13

193

Extinction or survival: partulid tree snails in American Samoa?  

Microsoft Academic Search

Four partulid tree snail species are known from American Samoa. In 1998, we surveyed the recently established National Park (units on three islands: Tutuila, Tau, Ofu) and neighboring areas for partulids. On Tutuila, Samoana abbreviata, previously considered probably extinct, was extremely rare (15 snails seen); Samoana conicawas more common (288 snails) but still rare; Eua zebrina was the most common

ROBERT H. COWIE; ROBERT P. COOK

2001-01-01

194

Availability of Water In The Upper Martian Surface  

NASA Astrophysics Data System (ADS)

Availability of water in the upper Martian surface D. Möhlmann, DLR Institut für Raumsimulation51170, Köln,Germany Email:dirk.moehlmann@dlr.de It is the cur- rent opinion that at present water in the upper Martian surface is in the ice-phase. This ice can be found, if at all, at mid- and equatorial latitudes only in depths of decameters or deeper. Thus, water is expected to exist in the Martian surface far away from layers which are reached by the diurnal or seasonal solar radiation caused thermal wave. On the other side, morning fog indicates at some locations the existence of water in the upper surface layers, what are by definition those, which can be reached by the ther- mal wave. It is assumed since Viking (Jakosky et al., 1997) that this water has to be expected to be bound to the soil as adsorbate water in the upper surface l ayers above the ice in deeper layers. Model results are presented, which indicate for different soil parameters the possible amount of absorbate water in the upper Martian surface. It is expected that this adsorbate water may well be of biological importance.

Moehlmann, D.

195

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems  

SciTech Connect

Freshwater molluscs--snails and bivalves--have been used frequently as bioindicator organisms. With increasing needs for research on contaminant effects in freshwater ecosystems, this kind of biomonitoring is likely to develop further in the future. Molluscs can be used effectively for studies of both organic and inorganic contaminants; this review focuses on studies involving bioaccumulation and toxicity of metals. Two important advantages of snails and bivalves over most other freshwater organisms for biomonitoring research are their large size and limited mobility. In addition, they are abundant in many types of freshwater environments and are relatively easy to collect and identify. At metal concentrations that are within ranges common to natural waters, they are generally effective bioaccumulators of metals. Biomonitoring studies with freshwater molluscs have covered a wide diversity of species, metals, and environments. The principal generalization that can be drawn from this research is that bioaccumulation and toxicity are extremely situation dependent; hence, it is difficult to extrapolate results from any particular study to other situations where the biological species or environmental conditions are different. Even within one species, individual characteristics such as size, life stage, sex, and genotype can have significant effects on responses to contaminants. The bioavailability of the metal is highly variable and depends on pH, presence of organic ligands, water hardness, and numerous other controlling factors. Despite this variability, past studies provide some general principles that can facilitate planning of research with freshwater snails and bivalves as metal bioindicators. These principles may also be useful in understanding and managing freshwater ecosystems.

Elder, J.F.; Collins, J.J. (U.S. Geological Survey, Madison, WI (United States))

1991-01-01

196

Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2008  

USGS Publications Warehouse

Surface water provides 5 billion gallons per day, or 78 percent, of the total freshwater used (including thermoelectric) in Georgia (Fanning, 2003). Climate, geology, and landforms control the natural distribution of Georgia's water resources. Georgia is a 'headwaters' State, with most of the rivers beginning in northern Georgia and increasing in size downstream (see map at right for major watersheds). Surface water is the primary source of water in the northern one-half of the State, including the Atlanta metropolitan area, where limited ground-water resources are difficult to obtain. In Georgia, periodic droughts exacerbate competition for surface-water supplies. Many areas of Georgia also face a threat of flooding because of spring frontal thunderstorms and the potential for hurricanes from both the Atlantic Ocean and Gulf of Mexico. As the population of Georgia increases, these flood risks will increase with development in flood-risk zones, particularly in the coastal region.

Geological Survey (U.S.)

2008-01-01

197

Assessment of information on ground-water/surface-water interactions in the northern midcontinent  

USGS Publications Warehouse

Ground-water/surface-water interactions are important to the hydrology of shallow aquifers, streams, lakes, and wetlands. Information on ground-water/surface-water interactions in the northern midcontinent was assessed. The ground-water/surface-water interactions in physiographic and climatic areas that contain many wetlands differed from the interactions in areas that consisted predominantly of alluvial aquifers along large streams. In both types of areas, however, the interactions are complex. The distribution of shallow ground-water observation wells in the northern midcontinent and the frequency of measurement were evaluated. Most shallow wells are located adjacent to major streams, especially in areas where wetlands are not a dominant surface-water feature. The frequency of measurement was inconsistent between states.

Strobel, Michael, L.

1995-01-01

198

Detection of water on road surface by the polarized light  

NASA Astrophysics Data System (ADS)

This report explains the working principle, structure, and performance of a new detector of water on a road surface paved with concrete by polarized light. Near the polarizing angle, reflected light from the road surface includes vertical and horizontal polarized components. Intensity difference of the two polarized lights is very small on the dry road surface. On the wet road surface, the vertical component decreases much more than horizontal component. Based on the above mentioned fact, experiments to detect water on a road surface were carried out using a rotating polarizer (41.3 rps) and a silicon pinphotodiode under the sunlight. Experimental results showed that this system could remotely detect water on the road surface over the area of a few square meters.

Kimura, Tadashi

1993-03-01

199

Flux balance models for the oxygen and carbon isotope compositions of land snail shells  

NASA Astrophysics Data System (ADS)

A simple flux balance model with a diffusive, evaporative boundary layer indicates that the time constant (characteristic time) for approach to oxygen isotope steady state in the body fluid of land snails is ˜19 min or less. These comparatively short times support an assumption that the snail's aragonitic shell is commonly precipitated from a body fluid that is at, or near, isotopic steady state. The model indicates that the steady-state ? 18O value of snail shell carbonate depends upon the temperature, relative humidity, ? 18O of the input liquid water, and ? 18O of ambient water vapor. Model shell ? 18O values were calculated for the warm, wet months corresponding to times of snail activity at some European sites. Linear regression of these predicted values against published, measured values yielded the expression: ? 18O calc = 0.93(±0.13) ? 18O meas -0.9(±0.2), with r 2 = 0.65. As indicated by the value of r 2, there is scatter in the relationship, but the slope and intercept are close to one and zero, respectively, which lends credence to the model. Therefore, temporal or spatial changes recorded in the ? 18O values of land snail shells appear to be selectively seasonal—commonly the warm, wet months—and include the effects of relative humidity. For carbon, the time constant for approach to isotopic steady state in the bicarbonate dissolved in the body fluid of land snails is predicted to be ˜16 min or less. New and published ? 13C measurements of aragonite shell and associated organic matter exhibit an overall correlation, but with considerable scatter. As noted by previous workers, 13C-rich dietary "limestone" may account for some of the scatter. Additional scatter, according to the model presented herein, could arise from changes in the proportion of total oxidized carbon that is expelled by the snail as bicarbonate dissolved in body fluid (i.e., effects of relative changes in metabolic rates). These results affirm the need for caution in the interpretation of ? 13C values of land snail aragonite shells solely in terms of dietary proportions of C 3 and C 4 plants.

Balakrishnan, Meena; Yapp, Crayton J.

2004-05-01

200

Chloride in ground water and surface water in the vicinity of selected surface-water sampling sites of the beneficial use monitoring program of Oklahoma, 2003  

USGS Publications Warehouse

The Oklahoma Water Resources Board Beneficial Use Monitoring Program reported exceedances of beneficial-use standards for chloride at 11 surface-water sampling sites from January to October 2002. The U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study to determine the chloride concentrations in ground water in the vicinity of Beneficial Use Monitoring Program surface-water sampling sites not meeting beneficial use standards for chloride and compare chloride concentrations in ground water and surface water. The chloride-impaired Beneficial Use Monitoring Program surface-water sampling sites are located in the western and southern regions of Oklahoma. The ground-water sampling sites were placed in proximity to the 11 surface-water sampling sites designated impaired by chloride by the Oklahoma Water Resources Board. Two surface-water sampling sites were located on the Beaver River (headwaters of the North Canadian River), three sites on the Cimarron River, one site on Sandy Creek, one site on North Fork Red River, and four sites on the Red River. Six ground-water samples were collected, when possible, from two test holes located upstream from each of the 11 Beneficial Use Monitoring Program surface-water sampling sites. One test hole was placed on the left bank and right bank, when possible, of each Beneficial Use Monitoring Program surfacewater sampling site. All test holes were located on alluvial deposits adjacent to the Beneficial Use Monitoring Program surface-water sampling sites within 0.5 mile of the stream. Top, middle, and bottom ground-water samples were collected from the alluvium at each test hole, when possible. Water properties of specific conductance, pH, water temperature, and dissolved oxygen were recorded in the field before sampling for chloride. The ground-water median chloride concentrations at 8 of the 11 Beneficial Use Monitoring Program sites were less than the surface-water median chloride concentrations. The Turpin and Beaver sites had similar ground-water and surface-water median chloride concentrations. The Buffalo site was the only site that had a large difference between the ground-water and surface-water chloride concentrations. The ground-water median chloride concentration was approximately 14,500 mg/L greater than the surface-water median chloride concentration at the Buffalo site.

Mashburn, Shana L.; Sughru, Michael P.

2004-01-01

201

Spring and surface water quality of the Cyprus ophiolites  

Microsoft Academic Search

A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1) Mg-HCO3, (2) Na-SO4-Cl-HCO3, (3) Na-Ca-Cl-SO4-OH-CO3, (4) Na-Cl-SO4 and (5) Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic\\/ultrabasic rock as modified by CO2-weathering. An

Colin Neal; Paul Shand

2002-01-01

202

Epigenetic Regulation of EMT: The Snail Story  

PubMed Central

While the epithelial-mesenchymal transition (EMT) plays a fundamental role during development, its deregulation can adversely promote tumor metastasis. The phenotypic and cellular plasticity of EMT indicates that it is subject to epigenetic regulation. In this review, we try to embrace recent findings on the mechanisms of the transcription factor Snail-mediated E-cadherin silencing, which is a hallmark of EMT. Our studies as well as those of others have clearly demonstrated that Snail can recruit multiple chromatin enzymes including LSD1, HDAC1/2, PRC2, G9a and Suv39H1 to the E-cadherin promoter. These enzymes function in a highly orchestrated fashion to generate heterochromatin and promote DNA methyltransferase (DNMT)-mediated DNA methylation at the promoter region. Disruption of the connection between Snail and these chromatin-modifying enzymes may represent an efficient strategy for the treatment of EMT-related diseases.

Lin, Yiwei; Dong, Chenfang; Zhou, Binhua P.

2014-01-01

203

Unique water-water coordination tailored by a metal surface  

NASA Astrophysics Data System (ADS)

At low coverage of water on Cu(110), substrate-mediated electrostatics lead to zigzagging chains along [001] as observed with STM [T. Yamada, S. Tamamori, H. Okuyama, and T. Aruga, ``Anisotropic water chain growth on Cu(110) observed with scanning tunneling microscopy'' Phys. Rev. Lett. 96, 036105 (2006)]. Using x-ray absorption spectroscopy we find an anomalous low-energy resonance at ~533.1 eV which, based on density functional theory spectrum simulations, we assign to an unexpected configuration of water units whose uncoordinated O-H bonds directly face those of their neighbors; this interaction repeats over trough sites with enhanced electron density and is analogous to the case of a hydrated electron.

Schiros, T.; Andersson, K. J.; MacNaughton, J.; Gladh, J.; Matsuda, A.; Öström, H.; Takahashi, O.; Pettersson, L. G. M.; Nilsson, A.; Ogasawara, H.

2013-06-01

204

Identifying and Mapping Seasonal Surface Water Frost with MGS TES  

NASA Astrophysics Data System (ADS)

The Thermal Emission Spectrometer (TES) visible/near-infrared and thermal infrared bolometers measured surface broadband albedo and temperature for more than three Mars years. As seasons progress on Mars, surface temperatures may fall below the frost point of volatiles in the atmosphere (namely, carbon dioxide and water). Systematic mapping of the spatial and temporal occurrence of these volatiles in the martian atmosphere, on the surface, and in the subsurface has shown their importance in understanding the climate of Mars. However, few studies have investigated seasonal surface water frost and its role in the global water cycle. We examine zonally-averaged TES daytime albedo, temperature, and water vapor abundance data [after Smith, 2004] to map the presence of surface water frost on Mars. Surface water frost occurs in the polar and mid latitudes, in regions with surface temperatures less than 220 K and above 150 K, and can significantly increase albedo relative to the bare surface. In the northern hemisphere water frost is most apparent in late fall/early winter, before the onset of carbon dioxide frost. Dust storms occurring near northern winter solstice affect albedo data and prevent us from putting a latitudinal lower limit on the water frost in the northern hemisphere. Regardless, seasonal water frost occurs at least as low as 48°N in Utopia Planitia, beginning at Ls=~230°, as observed by Viking Lander 2 [Svitek and Murray, 1990]. Daytime surface water frost was also observed at the Phoenix Lander site (68°N) beginning at Ls=~160° [Cull et al., 2010]. The timing of albedo variations observed by TES agree relatively well with lander observations of seasonal frost. Seasonal water frost is not detected during fall in the southern hemisphere. A potential explanation for this discrepancy, compared with frost detections in the north, is the disparity in atmospheric water vapor abundance between the two hemispheres. The frost point temperatures for water vapor in the southern hemisphere are ~5-10 K lower for the corresponding season and latitude in the north [Smith, 2004]. This inhibits the stability of water frost on the surface in the southern hemisphere and also lowers the maximum thickness of a water frost layer, potentially limiting its effect on surface albedo. Our work here shows that the seasonal progression in the northern hemisphere of Mars involves extensive deposition of water frost, similar in progression to the carbon dioxide seasonal ice cap. This behavior results in variation of surface albedo and therefore affects surface and subsurface temperatures, which could impact the distribution of ground ice. Surface frost and subsequent mixing of vapor back into the atmosphere likely plays an important role in the global water cycle. Mapping of water frost's geographical extent, timing, and impact on surface albedo can provide insight into the processes controlling the present Martian climate. References: Cull, S. et al. (2010) JGR, 115, E00E19. Smith, M. D. (2004) Icarus, 167, 148-165. Svitek, T. and Murray, B. (1990) JGR, 95(B2), 1495-1510.

Bapst, J.; Bandfield, J. L.; Wood, S. E.

2013-12-01

205

Distribution patterns of polychlorinated biphenyl congeners in water, sediment and biota from Midway Atoll (North Pacific Ocean)  

Microsoft Academic Search

To increase our understanding of critical pathways of polychlorinated biphenyl (PCB) transfer from abiotic media into marine organisms, this study quantified 20 PCB congeners in surface water, sediment and tissues of marine biota (macrophytes, snails, urchins, bivalves, sea cucumbers, fishes) taken from Midway Atoll. PCBs 138, 153, 170, 180 and 187 were the most abundant congeners in all samples analysed.

Bruce Hope; Susan Scatolini; Eric Titus; Jeff Cotter

1997-01-01

206

Telesupervised remote surface water quality sensing  

Microsoft Academic Search

We present a fleet of autonomous Robot Sensor Boats (RSBs) developed for lake and river fresh water quality assessment and controlled by our Multilevel Autonomy Robot Telesupervision Architecture (MARTA). The RSBs are low cost, highly maneuverable, shallow draft sensor boats, developed as part of the Sensor Web program supported under the Advanced Information Systems Technology program of NASA's Earth Systems

G. Podnar; J. M. Dolan; Kian Hsiang Low; A. Elfes

2010-01-01

207

Silicon concentrations in UK surface waters  

Microsoft Academic Search

This paper describes the variations in silicon concentrations in UK waters for a wide range of catchment systems (near pristine, rural, and agricultural and urban impacted systems). The paper largely concerns silicon levels in streams, rivers and lakes based on extensive data collected as part of several research and monitoring initiatives of national and international standing. For a detailed study

Colin Neal; Margaret Neal; Brian Reynolds; Stephen C. Maberly; Linda May; Robert C. Ferrier; Jennifer Smith; Julie E. Parker

2005-01-01

208

A siphon gage for monitoring surface-water levels  

USGS Publications Warehouse

A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.

McCobb, T. D.; LeBlanc, D. R.; Socolow, R. S.

1999-01-01

209

Formation of Water on a Warm Amorphous Silicate Surface  

NASA Astrophysics Data System (ADS)

It is well established that reactions on interstellar dust grain surfaces are indispensable for water formation in space. Among all the intermediate products that lead to water formation, the OH radical is especially important because is a product of all the three main water formation surface routes, i.e., the hydrogenation of O, O2, and O3, and it also connects these three routes. The desorption energy of OH from dust grain surfaces, along with dust grain temperature, determines the availability OH for grain surface versus gas-phase reactions. We experimentally investigated water formation on the surface of a warm amorphous silicate via H+O3?OH+O2. The surface temperature was kept at 50 K so as to exclude the interference of O2. It is found that OH has a significant residence time at 50 K. The OH desorption energy from amorphous silicate surface is calculated to be at least 1680 K, and possibly as high as 4760 K. Water is formed efficiently via OH+H and OH+H2, and the product H2O stays on the surface upon formation. Deuterium has also been used in place of hydrogen to check isotopic effects. This work is supported by NSF, Astronomy & Astrophysics Division (Grants No. 0908108 and 1311958) and NASA (Grant No. NNX12AF38G). We thank Dr. J.Brucato of the Astrophysical Observatory of Arcetri for providing the samples used in these experiments.

Vidali, Gianfranco; He, Jiao

2014-06-01

210

Quality of surface water in Missouri, water year 2009  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2009 water year (October 1, 2008, through September 30, 2009), data were collected at 75 stations-69 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, 1 spring sampled in cooperation with the U.S. Forest Service, and 3 stations sampled in cooperation with the Elk River Watershed Improvement Association. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

Barr, Miya N.

2010-01-01

211

LANDSCAPE INDICATORS OF SURFACE WATER CONDITIONS  

EPA Science Inventory

This task comprises three inter-related projects: 1) impervious surface mapping and evaluation of its impact ; 2) detection of BMPs and estimation of their ability to reduce nutrient input into streams, and; 3) detection of isolated wetlands. Each substask addresses critical is...

212

Role of water in polymer surface modification using organosilanes  

NASA Astrophysics Data System (ADS)

In general, polymers exhibit excellent bulk properties but may not possess specific surface properties for successful applications in biomaterials and nanotechnology. Surface modification of polymers with the self-assembled monolayers (SAMs) of organosilanes - ‘Silanization’ - is an attractive approach to alter surface properties without altering the polymer’s desired bulk properties. However, a pretreatment such as exposure to UV/O or plasma is normally required to generate active surface groups prior to silanization. These pretreatments cause undesirable surface changes such as severe surface roughening and excessive surface damage. Recent studies in silanization suggest that the presence of water or OH groups on the surface is essential to form SAMs. In this study we investigated the importance of surface water layer and OH groups in the formation of SAMs for a variety of polymers. The pre and post-modified polymers were examined using fourier transform infrared spectrometry, scanning probe microscopy and contact angle measurements. The results show that organosilanes can be grafted to a polymer surface as long as a water layer can be physisorbed to the surface or the polymer itself contains OH groups. However the monolayers formed are less organized compared to those formed on silicon wafers due to the amorphous nature of the polymers.

Thallapalle, Pradeep Kumar; Zhang Newby, Bi-Min

2002-03-01

213

The Influence of Surfaces on the Structure of Water.  

National Technical Information Service (NTIS)

A combination of adsorption and calorimetric measurements was made to study structuring of water at cellulose acetate surfaces of varying polarity. In this work cellulose acetate powders with varying degrees of acetylation were used. The results obtained ...

M. Korsch W. V. Johnston

1972-01-01

214

TRACE ORGANIC CONTAMINANTS IN ANTHROPOGENICALLY ACIDIFIED SURFACE WATERS  

EPA Science Inventory

The biological effects of trace organic contaminants in anthropogenically acidified surface waters are mediated by the nature of the association of trace organics with dissolved and particulate organic matter (DOC and POC). his paper (1) briefly reviews available deposition estim...

215

Surface water connectivity dynamics of a large scale extreme flood  

NASA Astrophysics Data System (ADS)

Uses the MODIS surface water product observations of the 2011 Bangkok flood.A data gap filling method is developed to better preserve the dynamics of the event.We quantify surface water connectivity geostatistically to give new flood insights.There is a clear structure to the connectivity of the event through time and space.Changes and thresholds in the connectivity are linked to major flood mechanisms.

Trigg, Mark A.; Michaelides, Katerina; Neal, Jeffrey C.; Bates, Paul D.

2013-11-01

216

Miscellaneous surface-water data, Pecos River basin, New Mexico  

USGS Publications Warehouse

Miscellaneous surface-water data from the Pecos River basin of New Mexico are assembled into one table. Measurements and estimates of the discharge of streams, springs, and diversion canals and pumps that are not readily available to the public are given. The principal sources of information are published and unpublished reports and various records of the U.S. Geological Survey and the New Mexico State Engineer Office. Many thousands of surface-water discharge values are given. (USGS)

Cranston, C. Clare; Kues, Georgianna E.; Welder, G. E.

1981-01-01

217

Tracer injection techniques in flowing surface water  

NASA Astrophysics Data System (ADS)

Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed irregularities. The so-called pumping model provided good estimates of the storage in the hyporheic zone under different stream discharges and stream flow conditions along streams. Evaluations Hobøl River, Norway, and Säva Brook, Sweden, at two occasions in both stream indicate that the relative residence time in the hyporheic zone is linearly proportional to the squared Froude Number. The residence time is scaled with water depth and hydraulic conductivity of the bed. The effect of such transient storage in e.g. the hyporheic zone gives rise to a tailing, but the breakthrough curve become increasingly symmetrical with Damköhler number. Such a symmetrical breakthrough can be erroneously taken as an effect of in-stream dispersion, even though this similarity is merely due to the physical analogy of various advection velocities over the transport cross-section, differential advection.

Wörman, A.

2009-04-01

218

Perfluorinated Surfactants in Surface and Drinking Waters  

Microsoft Academic Search

Goal, Scope and Background. Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory interfer- ence and carcinogenity in animal experiments as well as partly long half-lives in humans. They possess compound-dependent extreme re- calcitrance against microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in ani- mals and humans. Methods. Surface and drinking

Martin JW; Smithwick MM; Hoekstra PF; Muir DCG

219

Reassigning the most stable surface of hydroxyapatite to the water resistant hydroxyl terminated (010) surface  

NASA Astrophysics Data System (ADS)

Understanding the surface stability and crystal growth morphology of hydroxyapatite is important to comprehend bone growth and repair processes and to engineer protein adsorption, cellular adhesion and biomineralization on calcium phosphate based bone grafts and implant coatings. It has generally been assumed from electronic structure calculations that the most stable hydroxyapatite surface is the (001) surface, terminated just above hydroxyl ions perpendicular to the {001} crystal plane. However, this is inconsistent with the known preferential growth direction of hydroxyapatite crystals and previous experimental work which indicates that, contrary to currently accepted theoretical predictions, it is actually the (010) surface that is preferentially exposed. The surface structure of the (010) face is still debated and needs reconciliation. In this work, we use a large set of density functional theory calculations to model the interaction of water with hydroxyapatite surfaces and probe the surface stability and resistance to hydrolytic remodeling of a range of surface faces including the (001) surface and the phosphate-exposed, calcium-exposed, and hydroxyl-exposed terminations of the (010) surface. For the (001) surface and the phosphate-exposed (010) surface, dissociative water adsorption is favorable. In contrast, the hydroxyl-terminated (010) surface will not split water and only molecular adsorption of water is possible. Our calculations show, overall, that the hydroxyl-terminated (010) surface is the most stable and thus should be the predominant form of the hydroxyapatite surface exposed in experiments. This finding reconciles discrepancies between the currently proposed surface terminations of hydroxyapatite and the experimentally observed crystal growth direction and surface stability, which may aid efforts to accelerate biomineralization and better control bone-repair processes on hydroxyapatite surfaces.

Zeglinski, Jacek; Nolan, Michael; Thompson, Damien; Tofail, Syed A. M.

2014-05-01

220

SURFACE WATER QUALITY PARAMETERS FOR MONITORING OIL SHALE DEVELOPMENT  

EPA Science Inventory

This report develops and recommends prioritized listings of chemical, physical, and biological parameters which can be used to assess the environmental impact of oil shale development on surface water resources. Each of the potential water-related problems is addressed in the con...

221

Survey of stable isotope values in Irish surface waters  

Microsoft Academic Search

We present a study of the spatial distribution of ?18O and ?D values of lake and river waters from 144 locations in Ireland. Before we can gain a better understanding of paleoclimate records derived from lacustrine carbonate minerals we must understand mechanisms that produce variation in isotope values of modern surface waters. The focus of this study is to provide

Aaron F. Diefendorf; William P. Patterson

2005-01-01

222

Tritium in surface waters of the Yenisei River basin.  

PubMed

This paper reports an investigation of the tritium content in the surface waters of the Yenisei River basin near the Mining and Chemical Combine (MCC). In 2001 the maximum tritium concentration in the Yenisei River did not exceed 4 +/- 1 Bq l(-1), which is consistent with the data of 1998-99. However, it has been found that there are surface waters containing enhanced tritium as compared with the background values for the Yenisei River. For instance, in the Ploskii Stream and the Shumikha River the maximum tritium concentrations amount to 168 and 81 Bq l(-1), respectively. The source of tritium in these surface waters is the last operating reactor at the MCC, which still uses the Yenisei water as coolant. In water and sediment samples of the Bolshaya Tel River (a tributary of the Yenisei River) the tritium content turned out to be at least 10 times higher than the background values for the Yenisei River. The measurements conducted at the RPA RADON (Moscow) revealed not only tritium but also the artificial radionuclide (14)C in the Bolshaya Tel samples. The data obtained suggest that the Bolshaya Tel River receives the major part of tritium from sediments rather than from the water catchment area. This allows the conclusion that there is water exchange between the surface waters and the radioactively contaminated underground horizons of the "Severny" testing site. PMID:12600760

Bolsunovsky, A Ya; Bondareva, L G

2003-01-01

223

Microbial community genomics in eastern Mediterranean Sea surface waters  

Microsoft Academic Search

Offshore waters of the eastern Mediterranean Sea are one of the most oligotrophic regions on Earth in which the primary productivity is phosphorus limited. To study the unexplored function and physiology of microbes inhabiting this system, we have analyzed a genomic library from the eastern Mediterranean Sea surface waters by sequencing both termini of nearly 5000 clones. Genome recruitment strategies

Roi Feingersch; Marcelino T Suzuki; Michael Shmoish; Itai Sharon; Gazalah Sabehi; Frédéric Partensky; Oded Béjà

2010-01-01

224

Tritium in surface waters of the Yenisei River basin  

Microsoft Academic Search

This paper reports an investigation of the tritium content in the surface waters of the Yenisei River basin near the Mining and Chemical Combine (MCC). In 2001 the maximum tritium concentration in the Yenisei River did not exceed 4 ± 1 Bq l–1, which is consistent with the data of 1998–99. However, it has been found that there are surface

A. Ya. Bolsunovsky; L. G. Bondareva

2003-01-01

225

Langmuir circulation inhibits near-surface water turbulence  

NASA Astrophysics Data System (ADS)

In the surface ocean, breaking waves are a major source of air bubbles and turbulent kinetic energy. During the presence of a consistent surface wind, these wave-generated bubbles, along with other surface material like seaweed or foam, can be drawn into long rows along the surface. Driving this organization is Langmuir circulation, a phenomenon in which the wind and waves cause surface waters to rotate helically, moving like a wire wrapped around a pole in the windward direction. These spiral currents oscillate between clockwise and counterclockwise rotations, such that in some places the surface waters are pushed together and in others they are pulled apart. Researchers have previously found that at sites of convergence the bubbles produced by breaking waves are pushed to depths of 15 meters or more, with important implications for air-sea gas mixing and other processes.

Schultz, Colin

2012-07-01

226

Occurrence of Giardia and Cryptosporidium spp. in surface water supplies.  

PubMed Central

Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for source waters of 66 surface water treatment plants in 14 states and 1 Canadian province. The results showed that cysts and oocysts were widely dispersed in the aquatic environment. Giardia spp. were detected in 81% of the raw water samples. Cryptosporidium spp. were found in 87% of the raw water locations. Overall, Giardia or Cryptosporidium spp. were detected in 97% of the raw water samples. Higher cyst and oocyst densities were associated with source waters receiving industrial or sewage effluents. Significant correlations were found between Giardia and Cryptosporidium densities and raw water quality parameters such as turbidity and total and fecal coliform levels. Statistical modeling suggests that cyst and oocyst densities could be predicted on the basis of watershed and water quality characteristics. The occurrence of high levels of Giardia cysts in raw water samples may require water utilities to apply treatment beyond that outlined in the Surface Water Treatment Rule of the U.S. Environmental Protection Agency.

LeChevallier, M W; Norton, W D; Lee, R G

1991-01-01

227

Factors influencing counts in an annual survey of Snail Kites in Florida  

USGS Publications Warehouse

Snail Kites (Rostrhamus sociabilis) in Florida were monitored between 1969 and 1994 using a quasi-systematic annual survey. We analyzed data from the annual Snail Kite survey using a generalized linear model where counts were regarded as over-dispersed Poisson random variables. This approach allowed us to investigate covariates that might have obscured temporal patterns of population change or induced spurious patterns in count data by influencing detection rates. We selected a model that distinguished effects related to these covariates from other temporal effects, allowing us to identify patterns of population change in count data. Snail Kite counts were influenced by observer differences, site effects, effort, and water levels. Because there was no temporal overlap of the primary observers who collected count data, patterns of change could be estimated within time intervals covered by an observer, but not for the intervals among observers. Modeled population change was quite different from the change in counts, suggesting that analyses based on unadjusted counts do not accurately model Snail Kite population change. Results from this analysis were consistent with previous reports of an association between water levels and counts, although further work is needed to determine whether water levels affect actual population size as well as detection rates of Snail Kites. Although the effects of variation in detection rates can sometimes be mitigated by including controls for factors related to detection rates, it is often difficult to distinguish factors wholly related to detection rates from factors related to population size. For factors related to both, count survey data cannot be adequately analyzed without explicit estimation of detection rates, using procedures such as capture-recapture.

Bennetts, R.E.; Link, W.A.; Sauer, J.R.; Sykes, P.W., Jr.

1999-01-01

228

Reduced water density at hydrophobic surfaces: Effect of dissolved gases  

NASA Astrophysics Data System (ADS)

Here, direct noninvasive neutron reflectivity measurements reveal the presence of a reduced (deuterated) water density region, with a sigmoidal density profile at the hydrophobic silane-water interface that depends on the type and concentration of dissolved gases in the water. Removal of dissolved gases decreases the width of the reduced water density region, and their reintroduction leads to its increase. When compared with recent computer simulations, a locally fluctuating density profile is proposed, whereas preexisting nanobubbles are excluded. The presence of a fluctuating reduced water density region between two hydrophobic surfaces and the attractive “depletion force” to which it leads may help explain the hydrophobic force and its reported diminution in deaerated water. Our results are also quantitatively consistent with recent dynamic surface force apparatus results that drastically revise previous estimates of the slip length of water flowing past hydrophobic surfaces from microns to ?20 nm. Our observations, therefore, go a long way toward reconciling three quite different types of experiments and phenomena: water depletion at hydrophobic surfaces, water slip at hydrophobic surfaces, and the hydrophobic interaction. Author contributions: D.A.D., E.B.W., J.N.I., and J.M. designed research; D.A.D., E.B.W., and J.M. performed research; D.A.D. and E.B.W. contributed new reagents/analytic tools; D.A.D. and E.B.W. analyzed data; and D.A.D., E.B.W., J.N.I., and J.M. wrote the paper.Abbreviations: AFM, atomic force microscopy; D2O, deuterated water; NR, neutron reflectivity; OTS, octadecyl-tricholorosilane; SLD, scattering length density.

Doshi, Dhaval A.; Watkins, Erik B.; Israelachvili, Jacob N.; Majewski, Jaroslaw

2005-07-01

229

Drainage areas of selected surface-water sites in Florida  

USGS Publications Warehouse

Drainage areas for about 1,500 surface-water sites on streams and lakes in Florida are contained in this report. Sites are described in relation to a nearby city or town, and are located by county, by latitude-longitude, and by topographic map on which it is located. In addition, the surface areas of lakes are shown for the elevation given on the topographic map. These data were retrieved from the Surface Water Index developed and maintained by the Hydrologic Records Section of the Florida District office of the U.S. Geological Survey.

Foose, Donald W.

1980-01-01

230

Amphibious fighting vehicle running on land and water surfaces  

US Patent & Trademark Office Database

An amphibious fighting vehicle capable of moving on a water surface including a front planing tracked belt disposed on a front portion of the amphibious fighting vehicle, a rear driving tracked belt, side buoys disposed on lateral sides of the amphibious fighting vehicle, a rear buoy disposed on a rear end of the amphibious fighting vehicle, the buoys assisting in setting an immersion line of the amphibious fighting vehicle at a predetermined value, and a set of identical engines that propel the amphibious fighting vehicle at a speed sufficient for movement on the water surface and a land surface.

2012-06-26

231

Characterization of nanobubbles on hydrophobic surfaces in water.  

PubMed

The aim of this paper is to quantitatively characterize the appearance, stability, density, and shape of surface nanobubbles on hydrophobic surfaces under varying conditions such as temperature and temperature variation, gas type and concentration, surfactants, and surface treatment. The method we adopt is atomic force microscopy (AFM) operated in the tapping mode. In particular, we show (i) that nanobubbles can slide along grooves under the influence of the AFM tip, (ii) that nanobubbles can spontaneously form by substrate heating, allowing for a comparison of the surface topology with and without the nanobubble, (iii) that a water temperature increase leads to a drastic increase in the nanobubble density, (iv) that pressurizing the water with CO2 also leads to a larger nanobubble density, but typically to smaller nanobubbles, (v) that alcohol-cleaning of the surface is crucial for the formation of surface nanobubbles, (vi) that adding 2-butanol as surfactant leads to considerably smaller surface nanobubbles, and (vii) that flushing water over alcohol-covered surfaces strongly enhances the formation of surface nanobubbles. PMID:17503857

Yang, Shangjiong; Dammer, Stephan M; Bremond, Nicolas; Zandvliet, Harold J W; Kooij, E Stefan; Lohse, Detlef

2007-06-19

232

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces  

PubMed Central

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-01-01

233

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces  

NASA Astrophysics Data System (ADS)

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

234

Impact of water withdrawals from groundwater and surface water on continental water storage variations  

Microsoft Academic Search

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to

P. Döll; H. Hoffmann-Dobrev; F. T. Portmann; S. Siebert; A. Eicker; M. Rodell; G. Strassberg; B. R. Scanlon

235

Water resources data for Maryland and Delaware, water year 1993. Volume 1. Surface-water data. Water-data report (Annual), 1 October 1992-30 September 1993  

Microsoft Academic Search

Water resources data for the 1993 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 104 gaging stations; stage and contents 1 reservoir; and water quality at 29 gaging stations. Also included are

R. W. James; R. H. Simmons; B. F. Strain

1994-01-01

236

Water resources data for Maryland and Delaware, water year 1992. Volume 1. Surface-water data. Water-data report (Annual), 1 October 1991-30 September 1992  

Microsoft Academic Search

Water resources data for the 1992 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. The volume (Volume 1. Surface-Water Data) contains records for water discharge at 101 gaging stations; stage and contents 1 reservoir; and water quality at 33 gaging stations. Also included are

R. W. James; R. H. Simmons; B. F. Strain; J. F. Hornlein

1993-01-01

237

Mate desertion in the snail kite  

USGS Publications Warehouse

Mate desertion during the breeding cycle was documented at 28 of 36 (78%) snail kite, Rostrhamus sociabilis nests in Florida between 1979 and 1983. Offspring mortality occurred at only one deserted nest, however. Parents that were deserted by their mates continued to care for their young until independence (3?5 additional weeks) and provided snails at a rate similar to that of both parents combined before desertion. Males and females deserted with nearly equal frequency, except in 1982 when more females deserted. No desertion occurred during drought years, whereas desertion occurred at nearly every nest during favourable conditions. The occurrence of mate desertion was generally related to indirect measures of snail abundance: foraging range, snail delivery rates to the young and growth rates. Small broods were deserted more frequently by females than by males and tended to be deserted earlier than large ones. After desertion, deserters had the opportunity to re-mate and nest again since breeding seasons were commonly lengthy, but whether they did so was impossible to determine conclusively in most cases. The deserted bird sometimes incurred increased energetic costs and lost breeding opportunities during periods of monoparental care.

Beissinger, S.R.; Snyder, N.F.R.

1988-01-01

238

MADAGASCAR'S BIOGEOGRAPELICALLY MOST INFORMATIVE LAND SNAIL TAXA  

Microsoft Academic Search

Madagascar's known native land-snail fauna is currently classified into 540 species (97% endemic) in 68 genera (29% endemic) in 25 families (0% endemic). Recent survey work throughout the island may as much as double this number of species and should provide, for the first time, adequate material and distributional data for robust cladistic and biogeographic analyses. Preliminary analysis of existing

Kenneth C. EMBERTON; Max F. RAKOTOMALALA

1996-01-01

239

What happens when snails get sick?  

NSDL National Science Digital Library

Scientists used to think that the two major groups of animals, vertebrates and invertebrates, protected themselves from getting sick in very different ways. A new study in snails suggests that both groups' immune systems might be slightly more similar than previously thought.

American Association for the Advancement of Science (AAAS;)

2004-07-09

240

Rupture and dewetting of water films on solid surfaces.  

PubMed

An experimental study was conducted to observe rupture and dewetting of water films, 0.5-2mm thick, on solid surfaces. The effects of surface roughness, wettability, protrusions on surfaces, and air entrapment between films and surfaces were studied. Film thickness measurements were made and film rupture and surface dewetting photographed. Experiments showed that liquid films ruptured first along the highest edges of test surfaces. Placing a protrusion on the surface had no effect-the liquid film continued to rupture along the edges. A thermodynamic model was developed to show that protrusions lower the surface energy of the system and promote wetting. Increasing surface roughness therefore increases film stability by resisting rupture and dewetting. Water films could be punctured by introducing an air bubble that burst and created a hole. The hole would close if the film was thick and the solid-liquid contact angle was either small or large; the hole would grow larger if the film was thin and the contact angle was in the mid-range (?80°). An analytical model that calculates the difference between the surface energies of the two states can be used to predict whether a hole would lead to surface dewetting or not. PMID:20817200

Mulji, Neil; Chandra, Sanjeev

2010-12-01

241

Dark solitons on the surface of water  

NASA Astrophysics Data System (ADS)

The nonlinear Schrödinger equation (NLS) models the evolution dynamics in time and space of weakly nonlinear water wave trains in finite or infinite depth. In the defocusing regime (finite depth), the NLS admits a family of soliton solutions, which describe the strong depression of wave envelopes. These solitons are referred to dark solitons and have been already observed in optics and in Bose-Einstein condensates. We present experimental results on gray and black solitons, propagating in a wave flume. Furthermore, we analyze the data and discuss the discrepancies observed with respect to theoretical predictions. The results prove that in the case of weak-nonlinearity of the waves, the NLS describes well the dynamics of nonlinear wave packets in finite depth.

Chabchoub, Amin

2014-05-01

242

Tensile testing of ultra-thin films on water surface  

NASA Astrophysics Data System (ADS)

The surface of water provides an excellent environment for gliding movement, in both nature and modern technology, from surface living animals such as the water strider, to Langmuir-Blodgett films. The high surface tension of water keeps the contacting objects afloat, and its low viscosity enables almost frictionless sliding on the surface. Here we utilize the water surface as a nearly ideal underlying support for free-standing ultra-thin films and develop a novel tensile testing method for the precise measurement of mechanical properties of the films. In this method, namely, the pseudo free-standing tensile test, all specimen preparation and testing procedures are performed on the water surface, resulting in easy handling and almost frictionless sliding without specimen damage or substrate effects. We further utilize van der Waals adhesion for the damage-free gripping of an ultra-thin film specimen. Our approach can potentially be used to explore the mechanical properties of emerging two-dimensional materials.

Kim, Jae-Han; Nizami, Adeel; Hwangbo, Yun; Jang, Bongkyun; Lee, Hak-Joo; Woo, Chang-Su; Hyun, Seungmin; Kim, Taek-Soo

2013-10-01

243

Circumnutation on the water surface: female flowers of Vallisneria.  

PubMed

Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water. PMID:23355948

Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

2013-01-01

244

Circumnutation on the water surface: female flowers of Vallisneria  

PubMed Central

Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water.

Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

2013-01-01

245

DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT  

EPA Science Inventory

A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5...

246

ARSENIC SORUCE IDENTIFICATION AT THE GROUND WATER-SURFACE WATER INTERACTION ZONE AT A CONTAMINATED SITE  

EPA Science Inventory

One of the challenges in assessing the current impact of the discharge of arsenic contaminated ground water into a surface water body is differentiating the arsenic ground-water flux versus dissolution of in-place contaminated sediments. A field investigation has been carried ou...

247

[Current status of surface water acidification in Northeast China].  

PubMed

In order to evaluate the status of surface water acidification in Northeast China, chemical composition of 33 small streams was investigated in August, 2011. It was found that only a few waters located in Changbai Mountain had pH of lower than 6.0, and all waters had acid neutralizing capacity (ANC) of higher than 0.2 meq x L(-1). This indicated that surface water acidification was not a regional environmental issue in Northeast China. HCO3- was the major anion, with SO4(2-) concentration mostly below 150 microeq x L(-1) and even much lower NO3- concentration. Low concentration of SO4(2-) and NO3- means no serious acid deposition in this area. However, the distribution of acidic forest soils, with low base cation weathering rate, could only provide limited buffering capacity for surface water to acidification in Northeast China, and the potential risk of water acidification still existed. Currently, acid deposition in Northeast Asia could hardly cause severe acidification of surface water. The neighboring countries should therefore not amplify the environmental impact by transboundary air pollutants from China. PMID:23914517

Xu, Guang-yi; Kang, Rong-hua; Luo, Yao; Duan, Lei

2013-05-01

248

SARAH2: A NEAR FIELD EXPOSURE ASSESSMENT MODEL FOR SURFACE WATER  

EPA Science Inventory

The near field surface water model (SARAH2) calculates maximum allowable hazardous waste concentrations, based on predicted exposure to humans or aquatic life from contaminated surface water. The surface water contamination pathways analyzed in SARAH2 include groundwater leachate...

249

Total Alkalinity of Surface Waters: A Map of the Western Region.  

National Technical Information Service (NTIS)

The map of total alkalinity of surface waters in the western region illustrates the general patterns of the relative potential sensitivity of surface waters to acidic deposition. As with geology and physiography, surface water alkalinity in the West varie...

J. M. Omernik G. E. Griffith

1986-01-01

250

A BLOODSUCKING SNAIL: THE COOPER'S NUTMEG, CANCELLARIA COOPERI GABB, PARASITIZES THE CALIFORNIA ELECTRIC RAY, TORPEDO CALIFORNICA AYRES  

Microsoft Academic Search

Feeding habits of the over 200 living species of Cancellarlidae are largely un known. The Cooper's nutmeg, Cancellaria cooperi, was seen by divers on the dorsal surface ofPacific electric rays, Torpedo californica. C. cooperi was observed to parasit ize electric rays in the laboratory. The snails made small cuts on the ray's ventral surface and inserted their proboscises into the

J. B. O'SULLIVAN; R. R. MCCONNAUGHEY; M. E. HUBER

251

Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance  

NASA Technical Reports Server (NTRS)

Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

Fisher, John W.; Hogan, John Andrew; Wignarajah, Kanapathipi; Pace, Gregory S.

2010-01-01

252

Origin of subdiffusion of water molecules on cell membrane surfaces  

NASA Astrophysics Data System (ADS)

Water molecules play an important role in providing unique environments for biological reactions on cell membranes. It is widely believed that water molecules form bridges that connect lipid molecules and stabilize cell membranes. Using all-atom molecular dynamics simulations, we show that translational and rotational diffusion of water molecules on lipid membrane surfaces exhibit subdiffusion and aging. Moreover, we provide evidence that both divergent mean trapping time (continuous-time random walk) and long-correlated noise (fractional Brownian motion) contribute to this subdiffusion. These results suggest that subdiffusion on cell membranes causes the water retardation, an enhancement of cell membrane stability, and a higher reaction efficiency.

Yamamoto, Eiji; Akimoto, Takuma; Yasui, Masato; Yasuoka, Kenji

2014-04-01

253

A 3' enhancer controls snail expression in melanoma cells.  

PubMed

The snail gene encodes a transcriptional repressor that functions during animal development and in cancer progression to promote epithelial-mesenchymal transitions. Strict spatial and temporal boundaries of Snail expression in development imply precise transcriptional control, which becomes inappropriately activated in many cancer subtypes. To gain insight into the molecular mechanism(s) governing transcriptional control of Snail, we analyze chromatin structural changes associated with Snail transcription in melanoma cells. Regardless of transcriptional status, the Snail promoter displays three constitutive DNase hypersensitive sites (HS) and a moderate level of histone H3 Lys(4) dimethylation. A robust HS is found in the 3' region of A375 melanoma cells, in which Snail is highly expressed, but is absent in cells not expressing Snail. This element is conserved throughout the mammalian lineage and strongly activates expression of a reporter in A375 and Colo829 melanoma cells, but not in keratinocytes or primary melanocytes. Activity of this enhancer is associated with enrichment of H3 Lys(4) dimethylation and H3 acetylation at both the enhancer and the promoter. Additionally, enhancer activity is associated with H3 Lys(4) trimethylation at the promoter. A physical interaction between the 3' enhancer and promoter was observed in Snail-expressing cells, demonstrating a direct role for the enhancer in Snail expression. These results suggest a model in which the Snail promoter is constitutively packaged in a poised chromatin structure that can be activated in melanoma cells by a tissue-specific enhancer, which physically contacts the promoter. PMID:17616667

Palmer, Matthew B; Majumder, Parimal; Green, Myesha R; Wade, Paul A; Boss, Jeremy M

2007-07-01

254

Cold hardiness abilities vary with the size of the land snail Cornu aspersum.  

PubMed

The land snail Cornu aspersum (syn. Helix aspersa) living in Brittany (France) can be considered partially freezing tolerant as it possesses a low ability to supercool and a limited capacity to bear freezing of its body tissues. The absence of a marked cold hardiness strategy permits the emphasis of the role of parameters such as individual size or water mass (W(M)) contained by the organism. Adult snails (shell diameter 30-32 mm) had a supercooling ability, about 1-1.5 degrees C lower than that of immatures (shell diameter 12-20 mm) and survived longer to an exposure to -5 degrees C, with an Lt(50) comprised between 6.0 and 9.8 h against 2.6 to 4.2 h for immature snails. This better ability to bear freezing was explained by the faster dynamic of body ice formation observed in small individuals, which attained ice lethal quantity more rapidly. At the species level, large snails will then tend to be more tolerant to freezing and small ones to be freezing avoidant, a statement also observable at the phylum level. PMID:15528169

Ansart, Armelle; Vernon, Philippe

2004-10-01

255

Sun Glitter Measurements for Monitoring Global Surface Waters  

NASA Astrophysics Data System (ADS)

Surface waters are a dynamic system, important to a range of parties from resource managers to global climate scientists. Current methods of data collection are insufficient to meet the data requirements of many of the interested parties. In this project we explore the advantages and limitations of a micro-satellite constellation system designed to utilize sun glint to monitor at the global scale monthly changes in area of surface water. Sun glint, a very bright, spectrally flat reflection, provides a strong signal indicating water in natural settings. Based upon our investigations and the research of others, we looked at the extent to which wind and above-water foliage affect the amount of sun glitter measured by a satellite sensor. We explored for one specific orbit the effective ground coverage and revisit rates for study areas in Alaska and Brazil, taking into account the probability density function for the number of lakes vs lake area. The results of our research suggest the scientific information of surface waters that potentially could be obtained from data provided by a constellation of sun glitter sensing micro satellites would supplement that expected to be provided by a planned radar satellite surface water monitoring system.

Apperson, A. T.; Vanderbilt, V. C.

2010-12-01

256

Modeling decadal timescale interactions between surface water and ground water in the central Everglades, Florida, USA  

USGS Publications Warehouse

Surface-water and ground-water flow are coupled in the central Everglades, although the remoteness of this system has hindered many previous attempts to quantify interactions between surface water and ground water. We modeled flow through a 43,000 ha basin in the central Everglades called Water Conservation Area 2A. The purpose of the model was to quantify recharge and discharge in the basin's vast interior areas. The presence and distribution of tritium in ground water was the principal constraint on the modeling, based on measurements in 25 research wells ranging in depth from 2 to 37 m. In addition to average characteristics of surface-water flow, the model parameters included depth of the layer of 'interactive' ground water that is actively exchanged with surface water, average residence time of interactive ground water, and the associated recharge and discharge fluxes across the wetland ground surface. Results indicated that only a relatively thin (8 m) layer of the 60 m deep surfical aquifer actively exchanges surface water and ground water on a decadal timescale. The calculated storage depth of interactive ground water was 3.1 m after adjustment for the porosity of peat and sandy limestone. Modeling of the tritium data yielded an average residence time of 90 years in interactive ground water, with associated recharge and discharge fluxes equal to 0.01 cm d -1. 3H/3He isotopic ratio measurements (which correct for effects of vertical mixing in the aquifer with deeper, tritium-dead water) were available from several wells, and these indicated an average residence time of 25 years, suggesting that residence time was overestimated using tritium measurements alone. Indeed, both residence time and storage depth would be expected to be overestimated due to vertical mixing. The estimate of recharge and discharge (0.01 cm d-1) that resulted from tritium modeling therefore is still considered reliable, because the ratio of residence time and storage depth (used to calculated recharge and discharge) is much less sensitive to vertical mixing compared with residence time alone. We conclude that a small but potentially significant component of flow through the Everglades is recharged to the aquifer and stored there for years to decades before discharged back to surface water. Long-term storage of water and solutes in the ground-water system beneath the wetlands has implications for restoration of Everglades water quality.

Harvey, J. W.; Newlin, J. T.; Krupa, S. L.

2006-01-01

257

The utility of surface temperature measurements for the remote sensing of surface soil water status  

NASA Technical Reports Server (NTRS)

Experiments carried out on an Avondale loam soil indicated that the thermal inertia concept of soil water content detection is reasonably sound. The volumetric water contents of surface soil layers between 2 and 4 cm thick were found to be linear functions of the amplitude of the diurnal surface soil temperature wave for clear day-night periods. They were also found to be linear functions of the daily maximum value of the surface soil-air-temperature differential. Tests on three additional soils ranging from sandy loam to clay indicated that the relations determined for Avondale loam could not be accurately applied to these other soil types. When the moisture characteristic curves of each soil were used to transform water contents into pressure potentials, however, it was found that soil water pressure potential could be determined without prior knowledge of soil type, and thus its value as a potential soil water status survey tool was significantly enhanced.

Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Schmugge, T. J.

1975-01-01

258

Effects of Human Activities on the Interaction of Ground Water and Surface Water  

NSDL National Science Digital Library

This information describes how human activities affect ground water and ground water recharge. After a discussion of point and nonpoint sources of contaminants, there is information about the effects of irrigation development, surface-water reservoirs, and removal of flood-plain vegetation on the interaction of ground water and surface water. The site also covers the effects of nitrogen use, pesticide application to agricultural lands, and atmospheric deposition on the quality of ground and surface water. All of the above are supported by illustrations. In addition, there is information about urban and industrial pollution, modification of river valleys including the construction of levees and reservoirs, and modification of the atmosphere, which includes atmospheric deposition and global warming.

259

Hydrologic Science and Satellite Measurements of Surface Water (Invited)  

NASA Astrophysics Data System (ADS)

While significant advances continue to be made for satellite measurements of surface waters, important science and application opportunities remain. Examples include the following: (1) Our current methods of measuring floodwater dynamics are either sparsely distributed or temporally inadequate. As an example, flood depths are measured by using high water marks, which capture only the peak of the flood wave, not its temporal variability. (2) Discharge is well measured at individual points along stream networks using in-situ gauges, but these do not capture within-reach hydraulic variability such as the water surface slope changes on the rising and falling limbs of flood waves. (3) Just a 1.0 mm/day error in ET over the Congo Basin translates to a 35,000 m3/s discharge error. Knowing the discharge of the Congo River and its many tributaries should significantly improve our understanding of the water balance throughout the basin. The Congo is exemplary of many other basins around the globe. (4) Arctic hydrology is punctuated by millions of unmeasured lakes. Globally, there might be as many as 30 million lakes larger than a hectare. Storage changes in these lakes are nearly unknown, but in the Arctic such changes are likely an indication of global warming. (5) Well over 100 rivers cross international boundaries, yet the sharing of water data is poor. Overcoming this helps to better manage the entire river basin while also providing a better assessment of potential water related disasters. The Surface Water and Ocean Topography (SWOT, http://swot.jpl.nasa.gov/) mission is designed to meet these needs by providing global measurements of surface water hydrodynamics. SWOT will allow estimates of discharge in rivers wider than 100m (50m goal) and storage changes in water bodies larger than 250m by 250m (and likely as small as one hectare).

Alsdorf, D. E.; Mognard, N. M.; Lettenmaier, D. P.

2010-12-01

260

Atrazine removal by ozonation processes in surface waters.  

PubMed

Atrazine (6-chloro-N-ethyl-N'-isopropyl-1,3,5-triazinedyl-2,4-diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continuously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time for the aqueous phase was kept at 10 min. Concentrations of some intermediates, including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine, were also followed. The nature of water, specifically the alkalinity and pH were found to be important variables that affected atrazine (ATZ) removal. Surface waters with low alkalinity and high pH allowed the highest removal of ATZ to be reached. There was an optimum hydrogen peroxide to ozone mass flow ratio that resulted in the highest ATZ removal in each surface water treated. This optimum was above the theoretical stoichiometry of the process. Therefore, to reach the maximum removal of ATZ in a O3/H2O2 process, more hydrogen peroxide was needed in the surface waters treated than in ultrapure water under similar experimental conditions. In some cases, UV radiation alone resulted in the removal of ATZ higher than ozonation alone. This was likely due to the alkalinity of the surface water. Ozonation and UV radiation processes yield different amounts of hydrogen peroxide. Combined ozonations (O3/H2O2 and O3/UV) lead to ATZ removals higher than single ozonation or UV radiation but the formation of intermediates was higher. PMID:10227193

Beltrán, F J; Rivas, J; Acedo, B

1999-05-01

261

Microcystins in potable surface waters: toxic effects and removal strategies.  

PubMed

In freshwater, harmful cyanobacterial blooms threaten to increase with global climate change and eutrophication of surface waters. In addition to the burden and necessity of removal of algal material during water treatment processes, bloom-forming cyanobacteria can produce a class of remarkably stable toxins, microcystins, difficult to remove from drinking water sources. A number of animal intoxications over the past 20 years have served as sentinels for widespread risk presented by microcystins. Cyanobacterial blooms have the potential to threaten severely both public health and the regional economy of affected communities, particularly those with limited infrastructure or resources. Our main objectives were to assess whether existing water treatment infrastructure provides sufficient protection against microcystin exposure, identify available options feasible to implement in resource-limited communities in bloom scenarios and to identify strategies for improved solutions. Finally, interventions at the watershed level aimed at bloom prevention and risk reduction for entry into potable water sources were outlined. We evaluated primary studies, reviews and reports for treatment options for microcystins in surface waters, potable water sources and treatment plants. Because of the difficulty of removal of microcystins, prevention is ideal; once in the public water supply, the coarse removal of cyanobacterial cells combined with secondary carbon filtration of dissolved toxins currently provides the greatest potential for protection of public health. Options for point of use filtration must be optimized to provide affordable and adequate protection for affected communities. PMID:24038121

Roegner, Amber F; Brena, Beatriz; González-Sapienza, Gualberto; Puschner, Birgit

2014-05-01

262

Gas transfer through wetland surface water due to waving vegetation  

NASA Astrophysics Data System (ADS)

We investigate the effect of honami motions in a wetland system, where ';honami' refers to the wind-driven movement of vegetation. We hypothesize that this movement stirs the water column and thus contributes to the transfer of dissolved gases across the air-water interface. To understand the magnitude of this effect, a wetland honami was simulated in the laboratory using an array of plastic tubes to represent vegetation. Starting from deoxygenated water, we measured dissolved oxygen at mid-depth in the water column using a YSI ProODO as the water equilibrated with the atmosphere. From this DO time series, we calculated the gas transfer velocity, k, using the thin film gas transport model. We compare the results to other drivers of gas transfer in wetland surface water, including thermal convection and wind shear at the air-water interface. The results can help predict the role that surface-water stirring plays in connecting wetland soils with the atmosphere. This, in turn, can help predict biogeochemical processes and wetlands' impacts on greenhouse gases.

Foster, M. R.; Variano, E. A.

2013-12-01

263

Zirconium fluoride glass - Surface crystals formed by reaction with water  

NASA Technical Reports Server (NTRS)

The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

1984-01-01

264

Relating aggregated surface water flux with Aquarius salinity measurement  

NASA Astrophysics Data System (ADS)

One of the original objectives of Aquarius is to use surface salinity measurement as a rain gauge to characterize the hydrologic balance. Rain affects Aquarius salinity measurements by changing the roughness and the brightness temperature, and the accumulated rain forms a fresh-water lens that dilutes the surface salinity. We have examined high frequency rainfall provided by the Tropical Rainfall Measuring Mission (TRMM) and Climate Prediction Center Morphing Technique (CMORPH), co-incident with about one year of Aquarius salinity measurements. The relation of rainfall accumulated over various periods and the Aquarius salinity measurement has been examined over various regions of the tropical oceans. Using surface ocean currents provided by the Ocean Surface Currents Analyses - Realtime (OSCAR) and fresh water flux from TRMM, combined with Aquarius salinity, oceanic salinity budget was examined and the role of precipitation and ocean dynamics were evaluated over various regions.

Xie, X.; Liu, W.

2012-12-01

265

The Th 232 concentration of surface ocean water  

Microsoft Academic Search

Previous workers have reported Th 232 concentrations in surface sea water ranging from 0.3 to 0.6 g\\/1000 1. Whereas these estimates were based on the analysis of single samples, the present work is based on a composite of 24 analyses of water collected from widely spaced parts of the ocean. A careful interpretation of the alpha spectrometer data indicates that

A. Kaufman

1969-01-01

266

Sensors and OBIA synergy for operational monitoring of surface water  

Microsoft Academic Search

This contribution will focus on combining Object Based Image Analysis (i.e. OBIA with e-Cognition 8) and recent sensors (i.e. Spot 5 XS, Pan and ALOS Prism, Avnir2, Palsar) to address the technical feasibility for an operational monitoring of surface water. Three cases of river meandering (India), flood mapping (Nepal) and dam's seasonal water level monitoring (Morocco) using recent sensors will

Eric Masson; Lucas Thenard

2010-01-01

267

Water molecule adsorption properties on BiVO4 surface  

NASA Astrophysics Data System (ADS)

The behavior of water molecules on the (100) surface of BiVO4 has been investigated using first-principles molecular dynamics in view of the crucial role in photo catalytic activities under visible light irradiation. The simulations show that H2O molecules are adsorbed in a non-dissociated molecular form on the fivefold coordinated Bi site. The adsorption energy was estimated to be ~0.58 eV/molecule onto the Bi-exposing surface at 300 K. The band gap of the system shrinks slightly (by ~0.2 eV) upon water adsorption.

Oshikiri, M.; Boero, M.; Matsushita, A.; Ye, J.

2006-09-01

268

The use of radar imagery for surface water investigations  

NASA Technical Reports Server (NTRS)

The paper is concerned with the interpretation of hydrologic features using L-band (HH) imagery collected by aircraft and Seasat systems. Areas of research needed to more precisely define the accuracy and repeatability of measurements related to the conditions of surfaces and boundaries of fresh water bodies are identified. These include: the definition of shoreline, the nature of variations in surface roughness across a water body and along streams and lake shores, and the separation of ambiguous conditions which appear similar to lakes.

Bryan, M. L.

1981-01-01

269

Surface-Water and Ground-Water Resources of Kendall County, Illinois  

USGS Publications Warehouse

Water-supply needs in Kendall County, in northern Illinois, are met exclusively from ground water derived from glacial drift aquifers and bedrock aquifers open to Silurian, Ordovician, and Cambrian System units. As a result of population growth in Kendall County and the surrounding area, water use has increased from about 1.2 million gallons per day in 1957 to more than 5 million gallons per day in 2000. The purpose of this report is to characterize the surface-water and ground-water resources of Kendall County. The report presents a compilation of available information on geology, surface-water and ground-water hydrology, water quality, and water use. The Fox River is the primary surface-water body in Kendall County and is used for both wastewater disposal and as a drinking-water supply upstream of the county. Water from the Fox River requires pretreatment for use as drinking water, but the river is a potentially viable additional source of water for the county. Glacial drift aquifers capable of yielding sufficient water for municipal supply are expected to be present in northern Kendall County, along the Fox River, and in the Newark Valley and its tributaries. Glacial drift aquifers capable of yielding sufficient water for residential supply are present in most of the county, with the exception of the southeastern portion. Volatile organic compounds and select trace metals and pesticides have been detected at low concentrations in glacial drift aquifers near waste-disposal sites. Agricultural-related constituents have been detected infrequently in glacial drift aquifers near agricultural areas. However, on the basis of the available data, widespread, consistent problems with water quality are not apparent in these aquifers. These aquifers are a viable source for additional water supply, but would require further characterization prior to full development. The shallow bedrock aquifer is composed of the sandstone units of the Ancell Group, the Prairie du Chien Group, the Galena-Platteville dolomite, the Maquoketa Group, and the Silurian dolomite where these units are at the bedrock surface. The availability of water from the shallow bedrock aquifer depends primarily on the geologic unit utilized. The Silurian dolomite, Galena-Platteville dolomite, and Ancell Group can yield sufficient water for residential and municipal supply in at least some parts of the county. The Cambrian-Ordovician aquifer system is composed of the most widespread, productive aquifers in northern Illinois and is used for water supply by a number of municipalities and industrial facilities. Water levels in the aquifer system have declined by as much as 600 feet in Kendall County and the aquifer frequently contains concentrations of radium above established health guidelines.

Kay, Robert T.; Mills, Patrick C.; Hogan, Jennifer L.; Arnold, Terri L.

2005-01-01

270

PROGRAMMED EFFECTS OF SURFACE WATER PRICE LEVELS ON U.S. AGRICULTURAL WATER USE AND PRODUCTION PATTERNS  

Microsoft Academic Search

The Iowa State University national interregional programming model is used to simulate increases in the price of surface water for irrigated agriculture, and to evaluate the economic impact of these increases on U.S. agricultural water use and production patterns. Four alternative price levels of surface water are analyzed with the base level being 1975 surface water prices. The model minimizes

Andrew S. Morton; Douglas A. Christensen; Earl O. Heady

1981-01-01

271

Hydrodynamic boundary condition of water on hydrophobic surfaces  

NASA Astrophysics Data System (ADS)

By combining total internal reflection fluorescence cross-correlation spectroscopy with Brownian dynamics simulations, we were able to measure the hydrodynamic boundary condition of water flowing over a smooth solid surface with exceptional accuracy. We analyzed the flow of aqueous electrolytes over glass coated with a layer of poly(dimethylsiloxane) (advancing contact angle ? = 108°) or perfluorosilane (? = 113°). Within an error of better than 10 nm the slip length was indistinguishable from zero on all surfaces.

Schaeffel, David; Yordanov, Stoyan; Schmelzeisen, Marcus; Yamamoto, Tetsuya; Kappl, Michael; Schmitz, Roman; Dünweg, Burkhard; Butt, Hans-Jürgen; Koynov, Kaloian

2013-05-01

272

Hydrodynamic boundary condition of water on hydrophobic surfaces.  

PubMed

By combining total internal reflection fluorescence cross-correlation spectroscopy with Brownian dynamics simulations, we were able to measure the hydrodynamic boundary condition of water flowing over a smooth solid surface with exceptional accuracy. We analyzed the flow of aqueous electrolytes over glass coated with a layer of poly(dimethylsiloxane) (advancing contact angle ? = 108°) or perfluorosilane (? = 113°). Within an error of better than 10 nm the slip length was indistinguishable from zero on all surfaces. PMID:23767478

Schaeffel, David; Yordanov, Stoyan; Schmelzeisen, Marcus; Yamamoto, Tetsuya; Kappl, Michael; Schmitz, Roman; Dünweg, Burkhard; Butt, Hans-Jürgen; Koynov, Kaloian

2013-05-01

273

The experimental determination of surface tension of supercooled water  

NASA Astrophysics Data System (ADS)

The surface tension of supercooled demineralized water in liquid state was measured using the elevation capillary method. Glass capillaries with an inner diameter from 0.35 mm to 0.20 mm were taken. The measurement was carried out from the ambient temperature down to -12 °C at normal pressure. The measured values of the surface increasing tension at decreasing temperature were compared with published experimental data and with the current IAPWS equation.

Mareš, Radim; Kalová, Jana

2014-03-01

274

Confirming Water Ice on the Surface of Asteroid 24 Themis  

NASA Astrophysics Data System (ADS)

We have confirmed the detection of a surprising, and so far unique, absorption feature on a main-belt asteroid, 24 Themis. Our 2 to 4 micron reflectance spectra were obtained over 7 hours (84% of Themis’ rotational period) on January 23, 2008 UT, from NASA's Infrared Telescope Facility. All our spectra confirm the shape and depth of the 3.1 micron absorption reported by Rivkin and Emery (2008) and show this absorption is present throughout the asteroid's rotation. The shape and wavelength of this absorption is interpreted by Rivkin and Emery (2008) as due to water ice, as opposed to hydrated minerals originally suggested by Lebofsky et al. (1990). Our spectra fit well the same water ice model used by Rivkin and Emery (2008), and are significantly different from spectra of hydrated silicates found in asteroids and meteorites. As Rivkin and Emery (2008) state, "If confirmed, a finding of water ice on Themis would be the first detection of ice on an asteroidal surface, and the first detection of water per se (as opposed to OH) on an asteroidal surface." This likely presence of water ice opens up interesting possibilities that could transform current views of some asteroids. For example, since water ice is not stable on the surface of Themis at 3.2 AU over 4.5 Gy, what is its source? What does this imply about the interior of this asteroid and of other members of this family? Could impacts with this type of asteroid have been a significant source of Earth's water? The presence of water ice on 24 Themis would support arguments that the cometary activity in at least two small members of this family is driven by sublimation of water ice (Hsieh and Jewitt 2006) and that these "activated asteroids” originated in this family (Licandro et al. 2007).

Campins, Humberto; Hargrove, K.; Howell, E. S.; Kelley, M. S.; Licandro, J.; Mothé-Diniz, T.; Ziffer, J.; Fernandez, Y.; Pinilla-Alonso, N.

2009-09-01

275

DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES  

EPA Science Inventory

Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

276

Geochemical characterization of surface water and spring water in SE Kashmir Valley, western Himalaya: Implications to water-rock interaction  

NASA Astrophysics Data System (ADS)

Water samples from precipitation, glacier melt, snow melt, glacial lake, streams and karst springs were collected across SE of Kashmir Valley, to understand the hydrogeochemical processes governing the evolution of the water in a natural and non-industrial area of western Himalayas. The time series data on solute chemistry suggest that the hydrochemical processes controlling the chemistry of spring waters is more complex than the surface water. This is attributed to more time available for infiltrating water to interact with the diverse host lithology. Total dissolved solids (TDS), in general, increases with decrease in altitude. However, high TDS of some streams at higher altitudes and low TDS of some springs at lower altitudes indicated contribution of high TDS waters from glacial lakes and low TDS waters from streams, respectively. The results show that some karst springs are recharged by surface water; Achabalnag by the Bringi stream and Andernag and Martandnag by the Liddar stream. Calcite dissolution, dedolomitization and silicate weathering were found to be the main processes controlling the chemistry of the spring waters and calcite dissolution as the dominant process in controlling the chemistry of the surface waters. The spring waters were undersaturated with respect to calcite and dolomite in most of the seasons except in November, which is attributed to the replenishment of the CO2 by recharging waters during most of the seasons.

Jeelani, Gh; Bhat, Nadeem A.; Shivanna, K.; Bhat, M. Y.

2011-10-01

277

Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations.  

National Technical Information Service (NTIS)

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use mod...

A. Eicker F. T. Portmann G. Strassberg H. Hoffmann-Dobrev M. Rodell P. Doell S. Siebert

2011-01-01

278

Radiolysis Concerns for Water Shielding in Fission Surface Power Applications  

SciTech Connect

This paper presents an overview of radiolysis concerns with regard to water shields for fission surface power. A review of the radiolysis process is presented and key parameters and trends are identified. From this understanding of the radiolytic decomposition of water, shield pressurization and corrosion are identified as the primary concerns. Existing experimental and modeling data addressing concerns are summarized. It was found that radiolysis of pure water in a closed volume results in minimal, if any net decomposition, and therefore reduces the potential for shield pressurization and corrosion.

Schoenfeld, Michael P. [NASA Marshall Space Flight Center, ER24, MSFC, AL 35812 (United States); Anghaie, Samim [Innovative Space Power and Propulsion Institute, 800 SW Archer Rd. Bldg.554, P.O. Box 116502, University of Florida, Gainesville, FL 32611-6502 (United States)

2008-01-21

279

Water and Carbon Dioxide Adsorption at Olivine Surfaces  

SciTech Connect

Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbon dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.

Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

2013-11-14

280

Physiological and biochemical responses to cold and drought in the rock-dwelling pulmonate snail, Chondrina avenacea.  

PubMed

The pulmonate snail Chondrina avenacea lives on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. We found that tolerance to dry conditions was maintained at a very high level throughout the year and was mainly based on the snails' ability to promptly enter into estivation (quiescence) whenever they experienced drying out of their environment. Snails rapidly suppressed their metabolism and minimized their water loss using discontinuous gas exchange pattern. The metabolic suppression probably included periods of tissue hypoxia and anaerobism as indicated by accumulation of typical end products of anaerobic metabolism: lactate, alanine and succinate. Though the drought-induced metabolic suppression was sufficient to stimulate moderate increase of supercooling capacity, the seasonally highest levels of supercooling capacity and the highest tolerance to subzero temperatures were tightly linked to hibernation (diapause). Hibernating snails did not survive freezing of their body fluids and instead relied on supercooling strategy which allowed them to survive when air temperatures dropped to as low as -21 °C. No accumulation of low-molecular weight compounds (potential cryoprotectants) was detected in hibernating snails except for small amounts of the end products of anaerobic metabolism. PMID:23516021

Koštál, Vladimír; Rozsypal, Jan; Pech, Pavel; Zahradní?ková, Helena; Šimek, Petr

2013-08-01

281

Spring and surface water quality of the Cyprus ophiolites  

NASA Astrophysics Data System (ADS)

A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1) Mg-HCO3, (2) Na-SO4-Cl-HCO3, (3) Na-Ca-Cl-SO4-OH-CO3, (4) Na-Cl-SO4 and (5) Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water) and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high.

Neal, C.; Shand, P.

282

Comparison of pesticide residues in surface water and ground water of agriculture intensive areas.  

PubMed

The organochlorines (OClPs) and organophosphates (OPPs) pesticides in surface and ground water having intensive agriculture activity were investigated to evaluate their potential pollution and risks on human health. As per USEPA 8081 B method, liquid-liquid extraction followed by Gas-Chromatographic technique with electron capture detector and mass selective detector (GC-MS) were used for monitoring of pesticides. Among organochlorines, ?,?,?,? HCH's, aldrin, dicofol, DDT and its derivatives, ?,? endosulphan's and endosulphan-sulphate were analysed; dichlorovos, ethion, parathion-methyl, phorate, chlorpyrifos and profenofos were determined among organophosphates.As compared to ground water, higher concentrations of OClPs and OPPs were found in surface water. Throughout the monitoring study, ??-?HCH (0.39 ?g/L in Amravati region),??-?endosulphan (0.78 ?g/L in Yavatmal region), chlorpyrifos (0.25 ?g/L in Bhandara region) and parathion-methyl (0.09 ?g/L in Amravati region) are frequently found pesticide in ground water, whereas ?,?,?-HCH (0.39 ?g/L in Amravati region), ?,??-?endosulphan (0.42 ?g/L in Amravati region), dichlorovos (0.25 ?g/L in Yavatmal region), parathion-methyl (0.42 ?g/L in Bhandara region), phorate (0.33 ?g/L in Yavatmal region) were found in surface water.Surface water was found to be more contaminated than ground water with more number of and more concentrated pesticides. Among pesticides water samples are found to be more contaminated by organophosphate than organochlorine. Pesticides in the surface water samples from Bhandara and Yavatmal region exceeded the EU (European Union) limit of 1.0 ?g/L (sum of pesticide levels in surface water) but were within the WHO guidelines for individual pesticides. PMID:24398360

Lari, Summaiya Z; Khan, Noor A; Gandhi, Kavita N; Meshram, Tejal S; Thacker, Neeta P

2014-01-01

283

The Apollo lunar surface water vapor event revisited  

NASA Astrophysics Data System (ADS)

On March 7, 1971, the first sunrise following the Apollo 14 mission, the Suprathermal Ion Detector Experiment (SIDE) deployed at the Apollo 14 site reported an intense flux of ions whose mass per charge was consistent with water vapor. The amount of water is examined, and the various acceleration processes, responsible for accelerating ions into the SIDE, are discussed. It is concluded that during most of the event the observed water vapor ions were accelerated by the negative lunar surface electric potential and, secondly, that this event was probably the result of mission associated water vapor, either from the LM ascent and descent stage rockets or from residual water in the descent stage tanks.

Freeman, J. W., Jr.; Hills, H. K.

1991-11-01

284

Alarm response of hatchlings of the apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), to aqueous extracts of other individuals  

Microsoft Academic Search

We examined how hatchlings of the freshwater snail, Pomacea canaliculata, responded to aqueous extracts of conspecific hatchlings. Three, 3-day-old hatchlings were macerated in deionized water (1?mg hatchling per 1?ml water). When 0.5?ml of the aqueous extract was added to a test tube containing 10 hatchlings of the same age and 50?ml of water, the hatchlings in the water began to

Katsuya Ichinose; Yoichi Yusa; Kazuhiro Yoshida

2003-01-01

285

An integrable evolution equation for surface waves in deep water  

NASA Astrophysics Data System (ADS)

In order to describe the dynamics of monochromatic surface waves in deep water, we derive a nonlinear and dispersive system of equations for the free surface elevation and the free surface velocity from the Euler equations in infinite depth. From it, and using a multiscale perturbative method, an asymptotic model for small wave steepness ratio is derived. The model is shown to be completely integrable. The Lax pair, the first conserved quantities as well as the symmetries are exhibited. Theoretical and numerical studies reveal that it supports periodic progressive Stokes waves which peak and break in finite time. Comparison between the limiting wave solution of the asymptotic model and classical results is performed.

Kraenkel, R. A.; Leblond, H.; Manna, M. A.

2014-01-01

286

Inheritance of Schistosoma mansoni infection incompatibility in Biomphalaria alexandrina snails.  

PubMed

In this study, we looked at the inheritance of susceptibility and resistance to Schistosoma mansoni infection in the first generation of crossbred Biomphalaria alexandrina snails. Our ultimate goal is to use such information to develop a biological method of controlling schistosomiasis. We infected laboratory-bred snails with S. mansoni miracidia and examined cercarial shedding to determine susceptibility and resistance. Five parental groups were used: Group I contained 30 susceptible snails, Group II contained 30 resistant snails, Group III contained 15 susceptible and 15 resistant snails, Group IV contained 27 susceptible and three resistant snails and Group V contained three susceptible and 27 resistant snails. The percentage of resistant snails in the resulting progeny varied according to the ratio of susceptible and resistant parents per group; they are 7%, 100%, 68%, 45% and 97% from Groups I, II, III, IV and V, respectively. On increasing the percentage of resistant parent snails, the percentage of resistant progeny increased, while cercarial production in their susceptible progeny decreased. PMID:20428673

El Naga, Iman F Abou; Eissa, Maha M; Mossallam, Shereen F; El-Halim, Safaa I Abd

2010-03-01

287

Effect of non target snails on some biological of Lymnaea natalensis snails and their infection to Fasciola gigantica.  

PubMed

The influence of non-target freshwater snails (Melanoides tuberculata and Planorbis planorbis) on the capacity of Fasciola egg production F. gigantica miracidia to infect Lymnaea natalensis and their effect on mortality and growth rates showed that the snails exhibited a competitive ability against L. natalensis. The mortality rate existed in mixed cultures with snails was greatly increased, and increased with increase of snails number. The egg production and growth rate were negatively affected by the presence of M. tuberculata and P. planorbis which was more pronounced when snails were at higher ratio lL: 10D. Also, the snails showed significant degree of reduction in infection rate of L. natalensis with F. gigantica miracidia. PMID:17153707

Bakry, Fayez A; Hamdi, Salwa A H

2006-12-01

288

Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness.  

PubMed

The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of cold hardiness. When snails without cold hardiness were experimentally cold-acclimated, the amount of glycerol, glutamine, and carnosine increased, while glycogen and phenylalanine decreased. Overwintering cold-tolerant snails collected from a drained paddy field in November also showed increased glycerol in their bodies with decreasing glycogen concentration, compared to summer snails collected from a submerged field. Water content also decreased during the cold acclimation, although the water loss was minimal. These results indicate that the freshwater snail, P. canaliculata enhances cold hardiness by accumulation of some kinds of low molecular weight compounds in its body as some insects do. However, the actual function of each low molecular compound is still unknown. PMID:18190902

Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi

2008-04-01

289

The hydrochemical framework of surface water basins in southern Ghana  

NASA Astrophysics Data System (ADS)

Surface water resources play a crucial role in the domestic water delivery system in Ghana. In addition, sustainable food production is based on the quality and quantity of water resources available for irrigation purposes to supplement rain-fed agricultural activities in the country. The objective of this research was to determine the main controls on the hydrochemistry of surface water resources in the southern part of Ghana and assess the quality of water from these basins for irrigation activities in the area. R-mode factor and cluster analyses were applied to 625 data points from 6 river basins in southern Ghana after the data had been log transformed and standardized for homogeneity. This study finds that surface water chemistry in the south is controlled by the chemistry of silicate mineral weathering, chemistry of rainfall, fertilizers from agricultural activities in the area, as well as the weathering of carbonate minerals. A Gibb’s diagram plotted with total dissolved solids (TDS) on the vertical axis against (Na+ + K+)/(Ca2+ + K+ + Na+) on the horizontal axis indicates that rock weathering plays a significant role in the hydrochemistry. Activity diagrams for the CaO-Na2O-Al2O-SiO2-H2O and CaO-MgO-Al2O3-SiO2-H2O systems suggest that kaolinite is the most stable clay mineral phase in the system. In addition, an assessment of the irrigation quality of water from these basins suggests that the basins are largely low sodium—low to medium salinity basins, delivering water of acceptable quality for irrigation purposes.

Yidana, Sandow Mark

2009-04-01

290

NAWQA RETROSPECTIVE DATABASE FOR NUTRIENTS IN GROUND WATER AND SURFACE WATER  

EPA Science Inventory

The National Water-Quality Assessment (NAWQA) Program is designed to describe the status and trends in the quality of the Nations ground- and surface-water resources and to provide a sound understanding of the natural and human factors that affect the quality of these resources. ...

291

Surface water data at Los Alamos National Laboratory: 2008 water year  

SciTech Connect

The principal investigators collected and computed surface water discharge data from 69 stream-gage stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs— two that flow into Cañon de Valle and one that flows into Water Canyon.

Ortiz, David; Cata, Betsy; Kuyumjian, Gregory

2009-09-01

292

Surface Water Data at Los Alamos National Laboratory 2000 Water Year  

Microsoft Academic Search

The principal investigators collected and computed surface water discharge data from 23 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs, two that flow into Canon del Valle and one that flows into Water Canyon.

D. A. Shaull; M. R. Alexander; R. P. Reynolds; R. P. Romero; E. T. Riebsomer; C. T. McLean

2001-01-01

293

Field Evaluation Of Arsenic Speciation In Sediments At The Ground Water/Surface Water Interface  

EPA Science Inventory

The speciation and mineralogy of sediments contaminated with arsenic at the ground water/surface water interface of the Ft. Devens Super Fund Site in Ft. Devens, MA were determined using X-ray absorption fine structure and X-ray diffraction spectroscopy. Speciation and mineralog...

294

Manure Phosphorus and Surface Water Protection I: Basic Concepts of Soil and Water P  

NSDL National Science Digital Library

This lesson focuses on the process of eutrophication; the relationship between land application of manure and soil phosphorus (P) dynamics on P delivery to surface waters; and on the P dynamics in water bodies that result in increased P available to aquatic vegetation.

295

Surface Water Data at Los Alamos National Laboratory 2006 Water Year  

SciTech Connect

The principal investigators collected and computed surface water discharge data from 44 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data for 44 stations.

R.P. Romero, D. Ortiz, G. Kuyumjian

2007-08-01

296

PARTITION COEFFICIENTS FOR METALS IN SURFACE WATER, SOIL, AND WASTE  

EPA Science Inventory

This report presents metal partition coefficients for the surface water pathway and for the source model used in the Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment (3MRA) technology under development by the U.S. Environmental Protection Agency. Partition ...

297

Uranium in US surface, ground, and domestic waters  

SciTech Connect

The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium concentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

1981-04-01

298

SWOT, The Surface Water and Ocean Topography Satellite Mission (Invited)  

Microsoft Academic Search

Surface fresh water is essential for life, yet we have surprisingly poor knowledge of its variability in space and time. Similarly, ocean circulation fundamentally drives global climate variability, yet the ocean current and eddy field that affects ocean circulation and heat transport at the sub-mesoscale resolution and particularly near coastal and estuary regions, is poorly known. About 50% of the

D. Alsdorf; K. Andreadis; P. D. Bates; S. Biancamaria; E. Clark; M. T. Durand; L. Fu; H. Lee; D. P. Lettenmaier; N. M. Mognard; D. Moller; R. A. Morrow; E. Rodriguez; C. Shum

2009-01-01

299

Shale gas development impacts on surface water quality in Pennsylvania.  

PubMed

Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl(-)) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl(-) concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl(-) concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

Olmstead, Sheila M; Muehlenbachs, Lucija A; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J

2013-03-26

300

Shale gas development impacts on surface water quality in Pennsylvania  

PubMed Central

Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl?) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl? concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl? concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases.

Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

2013-01-01

301

RTK GPS water level measurement on dynamic sea surface  

Microsoft Academic Search

In recent years, Global Positioning System (GPS) receivers have been placed on buoys to determine the height of sea surface. GPS buoy always have an advantages over traditional techniques in measuring water level, which is their ability to determine heights relative to an absolute reference frame. There are scenarios where it is not practical or difficult to install a conventional

Siti Hawa Mohd Ngagipar; Othman Mohd Yusof

2011-01-01

302

Carbon dioxide supersaturation in the surface waters of lakes  

Microsoft Academic Search

Data on the partial pressure of carbon dioxide (COâ) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within {+-}20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure

J. J. Cole; N. F. Caraco; G. W. Kling; T. K. Kratz

1994-01-01

303

RATES, CONSTANTS, AND KINETICS FORMULATIONS IN SURFACE WATER QUALITY MODELING  

EPA Science Inventory

Recent studies are reviewed to provide a comprehensive volume on state-of-the-art formulations used in surface water quality modeling along with accepted values for rate constants and coefficients. Topics covered include system geometric representation (spatial and temporal), phy...

304

Spray production by air bubbles bursting on a water surface  

Microsoft Academic Search

The size and two components of the ejection velocity of the jet droplets generated by bursting bubbles on a water surface have been measured by a phase Doppler particle analyzer. The experiments are for bubbles of diameters in the range 200-1000 mum, which produced drops in the range of 10-150 mum. A careful analysis of raw data allowed the top

A. Rossodivita; P. Andreussi

1999-01-01

305

Impact of rainfall on microbial contamination of surface water  

Microsoft Academic Search

Purpose – Increased annual precipitation and more frequent episodes with heavy precipitation are expected in Norway due to climate change. The purpose of this paper is to use two case studies to investigate effects of precipitation on the amounts of faecal indicator bacteria and parasitic protozoa (Cryptosporidium and Giardia) loaded to surface waters from catchment areas exposed to different faecal

Ingun Tryland; Lucy Robertson; Anne-Grete B. Blankenberg; Markus Lindholm; Thomas Rohrlack; Helge Liltved

2011-01-01

306

CHARACTERIZING SURFACE WATERS THAT MAY NOT REQUIRE FILTRATION  

EPA Science Inventory

A relatively clean raw surface water can be determined that is amenable to disinfection as the only controlling treatment process. The essential criteria and associated standards are: ecal coliform, 20 organisms/100 mL; Turbidity, 1.0 NTU; Color, 15 ACU; Chlorine Demand, 2 mg/L. ...

307

CONTROLLING STORM WATER RUNOFF WITH TRADABLE CREDITS FOR IMPERVIOUS SURFACES  

EPA Science Inventory

Storm water flow off impervious surface in a watershed can lead to stream degradation, habitat alteration, low base flows and toxic leading. We show that a properly designed tradable runoff credit (TRC) system creates economic incentives for landowners to employ best management p...

308

Solvers and Calibration Methods for Ground and Surface Water Models.  

National Technical Information Service (NTIS)

The activities of this project are focused on (1) solving the nonsmooth nonlinear least squares problems that arise in the calibration of groundwater and surface water models, (2) nonlinear solvers for non-Darcy models of saturated groundwater flow, (3) c...

C. T. Kelley

2010-01-01

309

Design Methodology of Free Water Surface Constructed Wetlands  

Microsoft Academic Search

Simple criteria, guidelines and models are established for free water surface (FWS) constructed wetland selection and preliminary sizing. The analysis employs models for FWS constructed wetland design, considering simultaneously the removal requirements and the hydraulics of the system. On the basis of these models, a step-by-step methodology is developed outlining the design procedure for new and performance evaluation for existing

Maria A. Economopoulou; Vassilios A. Tsihrintzis

2004-01-01

310

The Biological Control of the Snail Hosts of Schistosomes: The Role of Competitor Snails and Biological Invasions  

Microsoft Academic Search

\\u000a Biological control of the snail hosts of schistosomes has been ­considered in the last few decades as an alternative to molluscicides.\\u000a Several groups of organisms have been proposed to control snail hosts, but very few have proven their efficacy in the field.\\u000a Competitor snails can be considered as the most efficient biological control agents and numerous promising laboratory studies\\u000a and

Jean-Pierre Pointier; Patrice David; Philippe Jarne

311

Crayfish predation on the common pond snail (Lymnaea stagnalis): the effect of habitat complexity and snail size on foraging efficiency  

Microsoft Academic Search

Optimal foraging theory was used to explain selective foraging by the introduced signal crayfish (Pacifastacus leniusculus)\\u000a on the thin-shelled common pond snail (Lymnaea stagnalis). Crayfish predation efficiency was studied in relation to habitat\\u000a complexity and snail size. In a pool experiment (area 1.3 m2) single adult crayfish were allowed to feed on four size classes of snails for one week.

Per Nyström; Jose R. Pérez

1998-01-01

312

Appearance of aldehydes in the surface layer of lake waters.  

PubMed

The paper presents results concerning the changes in the content of aldehydes in samples of lake water collected near the lake surface. The study of lake waters was undertaken to explain which physicochemical parameters of the environment have the greatest influence on the level of aldehydes, which of the aldehydes are most often met in surface water and in what concentrations. We observed that formaldehyde, acetaldehyde, propanal, glyoxal, methylglyoxal and acetone were commonly present in surface water samples, while semi-volatile and poorly soluble aldehydes such as nonanal and decanal were observed seasonally. The contents of total aldehydes varied in a wide range, from 55 to 670 ?g/l, and the concentration of total organic carbon varied significantly from 3 to 18 mg /l, but there was no evident correlation between them in all of samples. The total content of aldehydes did not depend on the meteorological parameters such as air temperature, UV radiation and ozone concentration; however, it was noted that the level of carbonyl concentration is related to the period of intense precipitation: in the period of very low precipitations, the highest contents of total aldehydes were determined in all of the water samples, and in the periods of intense precipitations, the content of total aldehydes was drastically smaller. PMID:24671617

D?browska, Agata; Nawrocki, Jacek; Szel?g-Wasielewska, El?bieta

2014-07-01

313

Occurrence of perchlorate in drinking water, groundwater, surface water and human saliva from India  

Microsoft Academic Search

Perchlorate (ClO4-), which is used as an oxidizer in jet and rocket fuels, pyrotechnic devices and explosives, is a widespread contaminant in surface waters and groundwater of many countries. Perchlorate is known to affect thyroid function. Despite the compound’s widespread occurrence and potential health effects, perchlorate levels in drinking water in India are not known. In this study, water samples

Kurunthachalam Kannan; Meredith L. Praamsma; John F. Oldi; Tatsuya Kunisue; Ravindra K. Sinha

2009-01-01

314

Electrohydrodynamic deformation of water surface in a metal pin to water plate corona discharge system  

Microsoft Academic Search

Electrohydrodynamic deformation of water surface was investigated in a pin-to-plate gas discharge system that consisted of a pin electrode made of metal and an ion-conductive water electrode. In the condition of a lower applied voltage than the corona threshold, because an extremely small electrostatic attractive force, a Coulomb force in the order of 10 µN, was induced, water lifted up

Hiroyuki Kawamoto; Shinjiro Umezu

2005-01-01

315

Transport and Fate of Nitrate at the Ground Water-Surface Water Interface  

Microsoft Academic Search

We investigated the transport and fate of nitrate within the ground water-surface water interface of 5 agriculturally dominated streams across the United States in Maryland, Indiana, Nebraska, California, and Washington. Water samples were collected from the streambed at depths ranging from 0.3 to 3 m, in 2-5 transects along the stream, and at 3-5 points across each transect. At 2

L. J. Puckett; H. I. Essaid; C. Zamora; J. T. Wilson; H. M. Johnson; J. R. Vogel

2006-01-01

316

Photochemistry of Dissolved Organic Matter in Arctic Surface Waters  

NASA Astrophysics Data System (ADS)

It has been shown that persistent organic pollutants (POPs), transported to the Arctic by long-range processes, can potentially contaminate Arctic surface waters and affect both local ecosystems and human health. Once deposited, the behavior of these pollutants is poorly understood; particularly the processes that govern their lifetime and concentrations within the water column. Here, we discuss the photochemical degradation of several halogenated organic pollutants (e.g., lindane, hexachlorobenzene) as mediated by natural dissolved organic matter (DOM). These experiments were conducted both in a controlled laboratory setting using an artificial sunlight simulator, as well as in situ in Alaskan surface waters near Toolik Lake. Our findings to date show high variability in the photodegradation rates of the target POPs and can be correlated to both their structure and the type of DOM present.

Grannas, A. M.; Chin, Y.; Miller, P. L.

2003-12-01

317

Surface Chemistry and Water Dispersability of Carbon Black Materials  

SciTech Connect

Formulation of water-stable carbon black dispersions is a double-sided task, which requires selection of a proper dispersing agents and matching it with the properties of a specific carbon black. Among other properties that affect water dispersability of carbon blacks (particle size, surface area, and aggregate structure), surface chemistry plays a prime-order role. We have characterized physical and chemical properties of several carbon black materials, and correlated them with the stability of dispersions formed with ionic and non-ionic surfactants. In particular, chemical characterization of surface functional groups on carbon blacks based on potentiometric titration measurements (pKa spectra) provided a comprehensive picture of pH effects on dispersion stability. The results obtained were complemented by information from physical characterization methods, such as XPS and FTIR. The selection of a suitable dispersing agent able to withstand large pH variations will be discussed.

Contescu, Cristian I [ORNL; Baker, Frederick S [ORNL; Burchell, Timothy D [ORNL

2006-01-01

318

Cryptic, adaptive radiation of endoparasitic snails: sibling species of Leptoconchus (Gastropoda: Coralliophilidae) in corals  

Microsoft Academic Search

Coral reefs are renowned as complex ecosystems with an extremely large biodiversity. Parasite-host relationships contribute\\u000a substantially to this, but are poorly known. We describe the results of a study in which approximately 60,000 corals were\\u000a searched for parasitic Leptoconchus snails (Gastropoda: Coralliophilidae) in Indo-West Pacific waters of Egypt, the Maldives, Thailand, Palau and Indonesia.\\u000a We discovered an adaptive radiation of

Adriaan Gittenberger; Edmund Gittenberger

2011-01-01

319

Gametogenic cycle and size at first maturity of the Patagonic edible snail Buccinanops cochlidium from Argentina  

Microsoft Academic Search

Buccinanops cochlidium is a common edible snail from Argentinean shallow waters, which is being consumed locally in north Patagonia. Nevertheless,\\u000a there are no policies for their fisheries management. This study provides information about the reproductive cycle and size\\u000a at first maturity of B. cochlidium from San José Gulf, Argentina. In this species, the testes seemed to develop mature sperm all

Andrés Averbuj; Gregorio Bigatti; Pablo E. Penchaszadeh

2010-01-01

320

Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China  

PubMed Central

Background Owing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails. Methods Moisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails. Results A total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively. Conclusion The results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6.6 to 7.0, 22.73°C to 24.23°C, and 23.5 m to 26.0 m, respectively. The findings in this research will help in making an effective strategy to control snails and provide a method to analyze other factors.

2014-01-01

321

Ring-waves generated by water drops impacting on water surfaces at rest  

Microsoft Academic Search

Radar observations of the ocean surface can be affected by impacting raindrops. Ring-wave measurements are presented for drops of 2.2 and 2.8 mm in diameter impacting on fresh and salt water surfaces initially at rest. They are based on the observation of the mirror image of a sharp edge on the perturbed surface. The retrieved wave profiles show a rather

Christophe Craeye; Piotr W. Sobieski; Larry F. Bliven; Albert Guissard

1999-01-01

322

Hydraulic exchange between a coral reef and surface sea water  

SciTech Connect

Hydraulic exchange between overlying sea water and the internal structure of a patch reef in Kaneohe Bay, Oahu, Hawaii, was studied with an array of wells, 1, 2, and 4 m deep. Two natural chemical tracers, radon, and salinity, were used to calculate the exchange rate between surface sea water and reef interstitial waters. Dissolved radon concentrations are substantially higher in interstitial waters than is surface water. The degree of radon enrichment is quantitatively related to the time elapsed since interstitial water had equilibrated with the atmosphere. Residence time estimates are 1-40 days, with deeper wells having slower exchange. The average residence time for 1-m-deep wells was 2.1 days. A rainstorm-induced dilution of the salinity of Kaneohe Bay provides the second tracer. Samples of surface and reef interstitial waters following this salinity perturbation are used to calculate an average residence time of 2.6 days at a depth of 1 m and 42 days at a depth of 2 m. Three types of physical forces thought to cause exchange between surface and interstitial water are considered by measurement of the forcing functions and reef permeability. Hydraulic conductivities are about 50 m/d, with lower values near the seaward side of the reef. Most exchange seems to be caused by high-frequency, wave-driven oscillatory pumping and by unidirectional hydraulic head gradients (of uncertain origin) that are stable for at least 3-4 days. Wave-driven mixing is probably more important shallower in the reef, whereas head-driven flow may dominate deeper in the reef. Tidal pumping does not seem to contribute to exchange. All methods indicate that exchange in the upper part of Checker Reef is primarily through vertical exchange. The best estimate for the residence time of water at a depth of 1 m is 2 days. Water at depths of 204 m probably has a residence time of weeks to months. 49 refs., 8 figs., 6 tabs.

Tribble, G.W.; Sansone, F.J.; Li, Yuan-Hui [Univ. of Hawaii, Honolulu, Hi (United States)] [and others] [Univ. of Hawaii, Honolulu, Hi (United States); and others

1992-10-01

323

Sea, ice and surface water circulation, Alaskan Continental Shelf  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Two cruises were conducted in Cook Inlet to obtain ground truth. Forty-seven stations during 22-23 August and 68 stations during 25-29 September 1972 were occupied and temperature, salinity, percent light transmission, and suspended load of surface waters obtained. Similar data at various depths was also obtained at selected stations. Cook Inlet is an estuary with complex mixing of river discharges and ocean water. The Upper Cook Inlet shows a gradual and systematic decrease in salinity, however, west of Kenai the mixing of waters is complex. The sediments in suspension originating at the head of the inlet generally settle out east of Kenai and Drift River. Sediment load in suspension decreased gradually from 1700 mg/1 near Anchorage to about 50 mg/1 in the Narrows. In the Lower Cook Inlet the suspended load varied between 1-10 mg/1. Surface waters with sediments in suspension and ocean water with relatively lower sediment concentration are clearly discernible in ERTS-1 images obtained during September 18, 1972 pass over Cook Inlet. The movement and mixing of these waters can also be delineated in the images.

Wright, F. F. (principal investigator); Sharma, G. D.

1972-01-01

324

Optimizing Nanopore Surface Properties for High-Efficiency Water Desalination  

NASA Astrophysics Data System (ADS)

As water resources worldwide become rapidly scarcer, it is becoming increasingly important to devise new techniques to obtain clean water from seawater. At present, water purification technologies are limited by costly energy requirements relative to the theoretical thermodynamic limit and by insufficient understanding of the physical processes underlying ion filtration and fluid transport at the molecular scale. New advances in computational materials science offer a promising way to deepen our understanding of these physical phenomena. In this presentation, we describe a new approach for high-efficiency water desalination based on surface-engineered porous materials. This approach is especially relevant for promising technologies such as nanofiltration and membrane distillation, which offers promising advantages over traditional desalination technologies using mesoporous membranes that are only permeable to pure water vapor. More accurate molecular modeling of mesoporous and nanoporous materials represents a key step towards efficient large-scale treatment of seawater. Results regarding the effect of pore properties (surface texture, morphology, density, tortuosity) on desired performance characteristics such as ion selectivity, maximal water flux and energy requirements will be presented.

Cohen-Tanugi, David; Grossman, Jeffrey

2011-03-01

325

A Study on Water Surface Profiles of Rivers with Constriction  

NASA Astrophysics Data System (ADS)

Water surface profile of rivers with constrictions is precious in both classic hydraulics and river management practice. This study was conducted to clarify the essences of the water surface profiles. 3 cases of experiments and 1D numerical calculations with different discharges were made in the study and analysis solutions of the non-linear basic equation of surface profile in varied flow without considering friction were derived. The manning's number was kept in the same in each case by using crosspiece roughness. We found a new type of water surface profile of varied flow from the results of 1D numerical calculation and that of experiments and named it as Mc curve because of its mild condition with constriction segment. This kind of curves appears as a nature phenomenon ubiquitously. The process of water surface forming is dynamic and bore occurs at the upper side of constriction during increasing discharge before the surface profile formed. As a theoretical work, 3 analysis solutions were derived included 2 physical-meaning solutions in the study by using Man-Machine system. One of the derived physical-meaning solutions was confirmed that it is validity by comparing to the results of 1D numerical calculation and that of experiments. The solution represents a flow profile from under critical condition at the upper side to super critical condition at the down side of constriction segment. The other derived physical-meaning solution represents a flow profile from super critical condition at the upper side to under critical condition at the down side of constriction segment. These two kinds of flow profiles exist in the nature but no theoretical solution can express the phenomenon. We find the depth distribution only concerned with unit width discharge distribution and critical depth under a constant discharge from the derived solutions. Therefor, the profile can be gained simply and precisely by using the theoretical solutions instead of numerical calculation even in practice.

Qian, Chaochao; Yamada, Tadashi

2013-04-01

326

Surface water and groundwater interactions in coastal wetlands  

NASA Astrophysics Data System (ADS)

Salt marshes are an important wetland system in the upper intertidal zone, interfacing the land and coastal water. Dominated by salt-tolerant plants, these wetlands provide essential eco-environmental services for maintaining coastal biodiversity. They also act as sediment traps and help stabilize the coastline. While they play an active role in moderating greenhouse gas emissions, these wetlands have become increasingly vulnerable to the impact of global climate change. Salt marshes are a complex hydrological system characterized by strong, dynamic interactions between surface water and groundwater, which underpin the wetland's eco-functionality. Bordered with coastal water, the marsh system undergoes cycles of inundation and exposure driven by the tide. This leads to dynamic, complex pore-water flow and solute transport in the marsh soil. Pore-water circulations occur at different spatial and temporal scales with strong link to the marsh topography. These circulations control solute transport between the marsh soil and the tidal creek, and ultimately affect the overall nutrient exchange between the marsh and coastal water. The pore-water flows also dictate the soil aeration conditions, which in turn affect marsh plant growth. This talk presents results and findings from recent numerical and experimental studies, focusing on the pore-water flow behaviour in the marsh soil under the influence of tides and density-gradients.

Li, Ling; Xin, Pei; Shen, Chengji

2014-05-01

327

Distribution and community-level effects of the Chinese mystery snail (Bellamya chinensis) in northern Wisconsin lakes  

Microsoft Academic Search

Managing invasive species requires infor- mation about their distributions and potential effects, but community-level impacts of invasive animals remain poorly understood. The Chinese mystery snail (Bellamya chinensis) is a large invasive gastropod that achieves high densities in waters across North Amer- ica, yet little is known about its ecological significance in invaded systems. We surveyed 44 lakes to describe the

Christopher T. Solomon; Julian D. Olden; Pieter T. J. Johnson; Robert T. Dillon Jr; M. Jake; Vander Zanden

2009-01-01

328

75 FR 52272 - Endangered and Threatened Wildlife and Plants; Removal of the Utah (Desert) Valvata Snail From...  

Federal Register 2010, 2011, 2012, 2013

...Reservoir indicated the highest Utah valvata snail...an indicator that oxygen levels are likely...in varying water flows and depths. The...g., dissolved oxygen and temperature...due to fluctuating flows and seasonal dewatering...reservoirs with relatively high proportional...

2010-08-25

329

Investigating surface water-well interaction using stable isotope ratios of water  

USGS Publications Warehouse

Because surface water can be a source of undesirable water quality in a drinking water well, an understanding of the amount of surface water and its travel time to the well is needed to assess a well's vulnerability. Stable isotope ratios of oxygen in river water at the City of La Crosse, Wisconsin, show peak-to-peak seasonal variation greater than 4??? in 2001 and 2002. This seasonal signal was identified in 7 of 13 city municipal wells, indicating that these 7 wells have appreciable surface water contributions and are potentially vulnerable to contaminants in the surface water. When looking at wells with more than 6 sampling events, a larger variation in ??18O compositions correlated with a larger fraction of surface water, suggesting that samples collected for oxygen isotopic composition over time may be useful for identifying the vulnerability to surface water influence even if a local meteoric water line is not available. A time series of ??18O from one of the municipal wells and from a piezometer located between the river and the municipal well showed that the travel time of flood water to the municipal well was approximately 2 months; non-flood arrival times were on the order of 9 months. Four independent methods were also used to assess time of travel. Three methods (groundwater temperature arrival times at the intermediate piezometer, virus-culture results, and particle tracking using a numerical groundwater-flow model) yielded flood and non-flood travel times of less than 1 year for this site. Age dating of one groundwater sample using 3H-3He methods estimated an age longer than 1 year, but was likely confounded by deviations from piston flow as noted by others. Chlorofluorocarbons and SF6 analyses were not useful at this site due to degradation and contamination, respectively. This work illustrates the utility of stable hydrogen and oxygen isotope ratios of water to determine the contribution and travel time of surface water in groundwater, and demonstrates the importance of using multiple methods to improve estimates for time of travel of 1 year or less. ?? 2004 Elsevier B.V. All rights reserved.

Hunt, R. J.; Coplen, T. B.; Haas, N. L.; Saad, D. A.; Borchardt, M. A.

2005-01-01

330

Regulatory Impact Analysis: Benefits and Costs of Final Surface Water Treatment Rule.  

National Technical Information Service (NTIS)

The report presents an analysis of the costs and benefits of controlling microbiological contaminants in public water systems using surface water sources through the criteria specified in the final Surface Water Treatment Rule (SWTR). The analysis was pre...

1989-01-01

331

Qualitative Uncertainty Assessment for Distributed Surface Water Quality Models  

NASA Astrophysics Data System (ADS)

Water quality models are often used to aid water quality regulators in the United States and around the world make critical decisions about how to improve water quality. Basin scale water quality models generally simplify spatial complexity to some degree. This problem is especially relevant in water quality modeling since the sources of pollution as well as the hydrologic drivers vary spatially across the landscape. The spatial complexity problem also presents specific challenges for estimating model predictive uncertainty. Questions of how to integrate multiple sources of stream water and water quality data at multiple locations are likely to be even more daunting than they are for surface water hydrologic models. At this time, given the complexity of water quality models and the general lack of data available, true statistical techniques of integrating, multiple data sources and calculating uncertainty bounds are probably not reasonable approaches. For this reason, we propose evaluation methods that are not based on statistics in order to evaluate the fit-to- purpose of particular model applications. Within SWAT2005, both a statistical method for uncertainty analysis, ParaSol, and an evaluation method, SUNGLASSES, have been incorporated. Additionally weighted averages of prediction errors are integrated into a global objective function and used to evaluate the reasonableness of model assumptions. This integration occurs across multiple objective functions and multiple locations. These methods have been applied in the context of a hypothetical water quality control problem in the San Jacinto watershed in southern California. The analysis includes an extension of the uncertainty analysis into its economic implications. The economic impact of the uncertainty methods proposed here are compared to more traditional uncertainty methods. The economic implications of uncertainty are shown to be important but only under circumstances where water quality targets are close to being met.

Meixner, T.; Bubb, K.; van Griensven, A.

2006-12-01

332

Water Surface and Velocity Measurement-River and Flume  

NASA Astrophysics Data System (ADS)

Understanding the flow of water in natural watercourses has become increasingly important as climate change increases the incidence of extreme rainfall events which cause flooding. Vegetation in rivers and streams reduce water conveyance and natural vegetation plays a critical role in flood events which needs to be understood more fully. A funded project at Loughborough University is therefore examining the influence of vegetation upon water flow, requiring measurement of both the 3-D water surface and flow velocities. Experimental work therefore requires the measurement of water surface morphology and velocity (i.e. speed and direction) in a controlled laboratory environment using a flume but also needs to be adaptable to work in a real river. Measuring the 3D topographic characteristics and velocity field of a flowing water surface is difficult and the purpose of this paper is to describe recent experimental work to achieve this. After reviewing past work in this area, the use of close range digital photogrammetry for capturing both the 3D water surface and surface velocity is described. The selected approach uses either two or three synchronised digital SLR cameras in combination with PhotoModeler for data processing, a commercial close range photogrammetric package. One critical aspect is the selection and distribution of appropriate floating marker points, which are critical if automated and appropriate measurement methods are to be used. Two distinct targeting approaches are available: either large and distinct specific floating markers or some fine material capable of providing appropriate texture. Initial work described in this paper uses specific marker points, which also provide the potential measuring surface velocity. The paper demonstrates that a high degree of measurement and marking automation is possible in a flume environment, where lighting influences can be highly controlled. When applied to a real river it is apparent that only lower degrees of automation are practicable. The study has demonstrated that although some automation is possible for point measurement, point matching needs to be manually guided in a natural environment where lighting cannot be controlled.

Chandler, J. H.; Ferreira, E.; Wackrow, R.; Shiono, K.

2014-06-01

333

SARAH, A SURFACE WATER ASSESSMENT MODEL FOR BACK CALCULATING REDUCTIONS IN ABIOTIC HAZARDOUS WASTES  

EPA Science Inventory

The nearfield surface model SARAH calculates maximum allowable hazardous waste concentrations based on predicted exposure to humans or aquatic life from contaminated surface water. The surface water contamination pathways analyzed in SARAH include groundwater leachate from a land...

334

Water resources data for New Jersey, water year 1992. Volume 1. Surface-water data. Water-data report (Annual), 1 October 1991-30 September 1992  

SciTech Connect

Water resources data for the 1992 water year for New Jersey consists of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. The volume of the report contains discharge records for 99 gaging stations; tide summaries for 2 stations; stage and contents for 37 lakes and reservoirs; water quality for 95 surface-water sites. Also included are data for 65 crest-stage partial-record stations, 13 tidal crest-stage gages, and 94 low-flow partial-record stations.

Bauersfeld, W.R.; Moshinsky, E.W.; Gurney, C.E.

1993-05-01

335

Surface Seal in the Water-Entry of Hydrophobic Spheres  

NASA Astrophysics Data System (ADS)

We examine the surface seal phenomenon observed in the water entry of hydrophobic spheres. Using high speed shadowgraph imaging we experimentally investigate the dependence of surface seal time and critical pressure on projectile size, density, and impact velocity. In the initial stage of impact the projectile slams into the free surface projecting a splash curtain upward. As the projectile descends into the fluid, an air cavity forms behind it and eventually pinches off from the atmosphere. Previous studies have primarily focused on the low velocity case where surface seal does not occur and the events above the free surface are often ignored. As the projectile velocity increases, the pressure drop within the cavity increases. Surface seal occurs when this pressure drop exceeds a critical pressure and is characterized by the closure of the splash curtain. The splash curtain domes over and seals the cavity above the free surface. This dome closure emits a downward jet which propagates into the air cavity from above and affects the later cavity dynamics. We present scaling arguments for critical pressure and surface seal time based on our observations.

Jackson, Benjamin; Jung, Sunghwan; Vlachos, Pavlos

2011-11-01

336

Trace-level mercury removal from surface water  

SciTech Connect

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water.

Klasson, K.T.; Bostick, D.T.

1998-06-01

337

Searching for liquid water in Europa by using surface observatories.  

PubMed

Liquid water, as far as we know, is an indispensable ingredient of life. Therefore, locating reservoirs of liquid water in extraterrestrial bodies is a necessary prerequisite to searching for life. Recent geological and geophysical observations from the Galileo spacecraft, though not unambiguous, hint at the possibility of a subsurface ocean in the Jovian moon Europa. After summarizing present evidence for liquid water in Europa, we show that electromagnetic and seismic observations made from as few as two surface observatories comprising a magnetometer and a seismometer offer the best hope of unambiguous characterization of the three-dimensional structure of the ocean and the deeper interior of this icy moon. The observatories would also help us infer the composition of the icy crust and the ocean water. PMID:12449858

Khurana, Krishan K; Kivelson, Margaret G; Russell, Christopher T

2002-01-01

338

'Water Systems' Coordination Plan and Development Program. Phase I. 'Water' Supply 'Systems', Waste 'Water' Pollution Control 'Systems' and Surface 'Water' Drainage 'Systems'.  

National Technical Information Service (NTIS)

The report is the first in a series of three reports treating with the water supply, wastewater pollution control and surface water drainage problems of the 3-county area around Memphis, Tennessee: DeSoto County, Mississippi, Crittenden County, Arkansas; ...

1972-01-01

339

Evaluation of Human Enteric Viruses in Surface Water and Drinking Water Resources in Southern Ghana  

PubMed Central

An estimated 884 million people worldwide do not have access to an improved drinking water source, and the microbial quality of these sources is often unknown. In this study, a combined tangential flow, hollow fiber ultrafiltration (UF), and real-time PCR method was applied to large volume (100 L) groundwater (N = 4), surface water (N = 9), and finished (i.e., receiving treatment) drinking water (N = 6) samples for the evaluation of human enteric viruses and bacterial indicators. Human enteric viruses including norovirus GI and GII, adenovirus, and polyomavirus were detected in five different samples including one groundwater, three surface water, and one drinking water sample. Total coliforms and Escherichia coli assessed for each sample before and after UF revealed a lack of correlation between bacterial indicators and the presence of human enteric viruses.

Gibson, Kristen E.; Opryszko, Melissa C.; Schissler, James T.; Guo, Yayi; Schwab, Kellogg J.

2011-01-01

340

Pesticide monitoring in surface water and groundwater using passive samplers  

NASA Astrophysics Data System (ADS)

Passive samplers as screening devices have been used within a czech national water quality monitoring network since 2002 (SPMD and DGT samplers for non polar substances and metals). The passive sampler monitoring of surface water was extended to polar substances, in 2005. Pesticide and pharmaceutical POCIS samplers have been exposed in surface water at 21 locations and analysed for polar pesticides, perfluorinated compounds, personal care products and pharmaceuticals. Pesticide POCIS samplers in groundwater were exposed at 5 locations and analysed for polar pesticides. The following active substances of plant protection products were analyzed in surface water and groundwater using LC/MS/MS: 2,4,5-T, 2,4-D, Acetochlor, Alachlor, Atrazine, Atrazine_desethyl, Azoxystrobin, Bentazone, Bromacil, Bromoxynil, Carbofuran, Clopyralid, Cyanazin, Desmetryn, Diazinon, Dicamba, Dichlobenil, Dichlorprop, Dimethoat, Diuron, Ethofumesate, Fenarimol, Fenhexamid, Fipronil, Fluazifop-p-butyl, Hexazinone, Chlorbromuron, Chlorotoluron, Imazethapyr, Isoproturon, Kresoxim-methyl, Linuron, MCPA, MCPP, Metalaxyl, Metamitron, Methabenzthiazuron, Methamidophos, Methidathion, Metobromuron, Metolachlor, Metoxuron, Metribuzin, Monolinuron, Nicosulfuron, Phorate, Phosalone, Phosphamidon, Prometryn, Propiconazole, Propyzamide, Pyridate, Rimsulfuron, Simazine, Tebuconazole, Terbuthylazine, Terbutryn, Thifensulfuron-methyl, Thiophanate-methyl and Tri-allate. The POCIS samplers performed very well being able to provide better picture than grab samples. The results show that polar pesticides and also perfluorinated compounds, personal care products and pharmaceuticals as well occur in hydrosphere of the Czech republic. Acknowledgment: Authors acknowledge the financial support of grant No. 2B06095 by the Ministry of Education, Youth and Sports.

Kodes, V.; Grabic, R.

2009-04-01

341

Acidic deposition--ecological effects on surface waters  

SciTech Connect

The acidification of soft water aquatic ecosystems, with consequent damage to the flora and fauna, is considered in this report. The evidence that environmental effects are ocurring is examined to see if a trend of increasing acidification can be related to changes in atmospheric deposition of sulphates and nitrates. Possible causes of change are considered, to clarify the contributions of variations in human activities and natural factors. It is concluded that acidic deposition, originating partly from emissions of sulphur and nitrogen compounds arising from man-made sources including combustion of fossil fuels, is causing acidification of surface waters in some areas of Europe and North America. There is proof that acidification of surface waters (to less than pH 6) is deleterious to many of the organisms whose habitat it forms. Acidified surface waters in some of the impacted areas are showing signs of recovery, where emissions of sulphur and nitrogen compounds from human activities are decreasing. There is some evidence that reversibility of acidification has started to occur, in some instances, about a decade after emissions were reduced. 219 refs., 13 figs., 9 tabs.

Harter, P.

1989-01-01

342

Assessment of the surface water quality in Northern Greece.  

PubMed

The application of different multivariate statistical approaches for the interpretation of a large and complex data matrix obtained during a monitoring program of surface waters in Northern Greece is presented in this study. The dataset consists of analytical results from a 3-yr survey conducted in the major river systems (Aliakmon, Axios, Gallikos, Loudias and Strymon) as well as streams, tributaries and ditches. Twenty-seven parameters have been monitored on 25 key sampling sites on monthly basis (total of 22,350 observations). The dataset was treated using cluster analysis (CA), principal component analysis and multiple regression analysis on principal components. CA showed four different groups of similarity between the sampling sites reflecting the different physicochemical characteristics and pollution levels of the studied water systems. Six latent factors were identified as responsible for the data structure explaining 90% of the total variance of the dataset and are conditionally named organic, nutrient, physicochemical, weathering, soil-leaching and toxic-anthropogenic factors. A multivariate receptor model was also applied for source apportionment estimating the contribution of identified sources to the concentration of the physicochemical parameters. This study presents the necessity and usefulness of multivariate statistical assessment of large and complex databases in order to get better information about the quality of surface water, the design of sampling and analytical protocols and the effective pollution control/management of the surface waters. PMID:12946893

Simeonov, V; Stratis, J A; Samara, C; Zachariadis, G; Voutsa, D; Anthemidis, A; Sofoniou, M; Kouimtzis, Th

2003-10-01

343

Mitigation of acid deposition: Liming of surface waters. Final report  

SciTech Connect

In recent years acid deposition has become a serious concern internationally. Scientific literature has documented the acidification of numerous lakes and streams in North America and Scandinavia resulting in the depletion or total loss of fisheries and other aquatic biota. Liming represents the only common corrective practice aimed specifically at remediating an affected acid receptor. This report reviews a range of liming technologies and liming materials, as well as the effect of surface-water liming on water quality and aquatic biota. As background to the liming discussion, the hydrologic cycle and the factors that make surface waters sensitive to acid deposition are also discussed. Finally, a brief review of some of the liming projects that have been conducted, or are currently in operation is presented, giving special emphasis to mitigation efforts in Maryland. Liming has been effectively used to counteract surface-water acidification in parts of Scandinavia, Canada, and the U.S. To date, liming has generally been shown to improve physical and chemical conditions and enhance the biological recovery of aquatic ecosystems affected by acidification.

Bartoshesky, J.; Price, R.; DeMuro, J.

1989-05-01

344

Assembled monolayers of hydrophilic particles on water surfaces.  

PubMed

A facile and quick approach to prepare self-assembled monolayers of water-dispersible particles on the water surface is presented. Particle suspensions in alcohols were dropped on a water reservoir to form long-range ordered monolayers of various particles, including spherical solid particles, soft hydrogel particles, metal nanoparticles, quantum dots, nanowires, single-wall carbon nanotubes (SWCNTs), nanoplates, and nanosheets. A systematic study was conducted on the variables affecting the monolayer assembly: the solubility parameter of spreading solvents, particle concentration, zeta potential of the particles in the suspension, surface tension of the water phase, hardness of the particles, and addition of a salt in the suspension. This method requires no hydrophobic surface treatment of the particles, which is useful to exploit these monolayer films without changing the native properties of the particles. The study highlights a quick 2D colloidal assembly without cracks in the wafer scale as well as transparent conductive thin films made of SWCNTs and graphenes. PMID:21962177

Moon, Geon Dae; Lee, Tae Il; Kim, Bongsoo; Chae, GeeSung; Kim, Jinook; Kim, SungHee; Myoung, Jae-Min; Jeong, Unyong

2011-11-22

345

Linking land use with pesticides in Dutch surface waters.  

PubMed

Compared with other European countries The Netherlands has a relatively high level of pesticide consumption, particularly in agriculture. Many of the compounds concerned end up in surface waters. Surface water quality is routinely monitored and numerous pesticides are found to be present in high concentrations, with various standards being regularly exceeded. Many standards-breaching pesticides exhibit regional patterns that can be traced back to land use. These patterns have been statistically analysed by correlating surface area per land use category with standards exceedance per pesticide, thereby identifying numerous significant correlations with respect to breaches of both the ecotoxicological standard (Maximum Tolerable Risk, MTR) and the drinking water standard. In the case of the MTR, greenhouse horticulture, floriculture and bulb-growing have the highest number as well as percentage of standard-breaching pesticides, despite these market segments being relatively small in terms of area cropped. Cereals, onions, vegetables, perennial border plants and pulses are also associated with many pesticides that exceed the drinking water standard. When a correction is made for cropped acreage, cereals and potatoes also prove to be a major contributor to monitoring sites where the MTR standard is exceeded. Over the period 1998-2006 the land-use categories with the most and highest percentage of standards-exceeding pesticides (greenhouse horticulture, bulb-growing and flower cultivation) showed an increase in the percentage of standards-exceeding compounds. PMID:23885409

Van't, Zelfde M T; Tamis, W L M; Vijver, M G; De Snoo, G R

2012-01-01

346

Surface-Water and Ground-Water Interactions in the Central Everglades, Florida  

USGS Publications Warehouse

Recharge and discharge are hydrological processes that cause Everglades surface water to be exchanged for subsurface water in the peat soil and the underlying sand and limestone aquifer. These interactions are thought to be important to water budgets, water quality, and ecology in the Everglades. Nonetheless, relatively few studies of surface water and ground water interactions have been conducted in the Everglades, especially in its vast interior areas. This report is a product of a cooperative investigation conducted by the USGS and the South Florida Water Management District (SFWMD) aimed at developing and testing techniques that would provide reliable estimates of recharge and discharge in interior areas of WCA-2A (Water Conservation Area 2A) and several other sites in the central Everglades. The new techniques quantified flow from surface water to the subsurface (recharge) and the opposite (discharge) using (1) Darcy-flux calculations based on measured vertical gradients in hydraulic head and hydraulic conductivity of peat; (2) modeling transport through peat and decay of the naturally occurring isotopes 224Ra and 223Ra (with half-lives of 4 and 11 days, respectively); and (3) modeling transport and decay of naturally occurring and 'bomb-pulse' tritium (half-life of 12.4 years) in ground water. Advantages and disadvantages of each method for quantifying recharge and discharge were compared. In addition, spatial and temporal variability of recharge and discharge were evaluated and controlling factors identified. A final goal was to develop appropriately simplified (that is, time averaged) expressions of the results that will be useful in addressing a broad range of hydrological and ecological problems in the Everglades. Results were compared with existing information about water budgets from the South Florida Water Management Model (SFWMM), a principal tool used by the South Florida Water Management District to plan many of the hydrological aspects of the Everglades restoration. A century of water management for flood control and water storage in the Everglades resulted in the creation of the Water Conservation Areas (WCAs). Construction of the major canals began in the 1910s and the systems of levees that enclose the basins and structures that move water between basins were largely completed by the 1950s. The abandoned wetlands that remained outside of the Water Conservation areas tended to dry out and subside by 10 feet or more, which created abrupt transitions in land-surface elevations and water levels across the levees. The increases in topographic and hydraulic gradients near the margins of the WCAs, along with rapid pumping of water between basins to achieve management objectives, have together altered the patterns of recharge and discharge in the Everglades. The most evident change is the increase in the magnitude of recharge (on the upgradient side) and discharge (on the downgradient side) of levees separating WCA-2A from other basins or areas outside. Recharge and discharge in the vast interior of WCA-2A also likely have increased, but fluxes in the interior wetlands are more subtle and more difficult to quantify compared with areas close to the levees. Surface-water and ground-water interactions differ in fundamental ways between wetlands near WCA-2A's boundaries and wetlands in the basin's interior. The levees that form the WCA's boundaries have introduced step functions in the topographic and hydraulic gradients that are important as a force to drive water flow across the wetland ground surface. The resulting recharge and discharge fluxes tend to be unidirectional (connecting points of recharge on the upgradient side of the levee with points of discharge on the downgradient side), and fluxes are also relatively steady in magnitude compared with fluxes in the interior. Recharge flow paths are also relatively deep in their extent near levees, with fluxes passing entirely through the 1-m peat layer and inte

Harvey, Judson W.; Newlin, Jessica T.; Krest, James M.; Choi, Jungyill; Nemeth, Eric A.; Krupa, Steven L.

2004-01-01

347

Free surface water wave 1-D LBGK predictions  

NASA Astrophysics Data System (ADS)

The performance of a single phase free surface lattice Boltzmann (LB) solver is investigated. The lattice-BGK (LBGK) model explores the free surface behavior with a focus on non-overturning water waves. The discretized equations are based on shallow water wave theory in viscous flow. Therefore, only flows with horizontal velocity dominating free surface waves is applicable. The solutions on uniform grids implement an elastic-collision scheme assuming slip boundaries at the tank walls. Simulations are carried out in horizontal base-excited square tanks. The forcing amplitude and the tank aspect ratios of are kept constant while the forcing frequency is varied off- and near resonance. At this water depth, the free surface was observed to slosh in a first sway mode initially; however, the following cycles would typically consist of traveling waves or bores. The flow typically remained 1-D in resonance cases except at the bore front and near the walls. The LB experiments are limited to flow simulations of weak bores which occurred near resonance with forcing amplitude in the order of . The LB solutions were in good agreement with a Riemann solver and agreed fairly well with experimental data.

Frandsen, J. B.

2006-07-01

348

Determination of antibiotic residues in manure, soil, and surface waters  

USGS Publications Warehouse

In the last years more and more often detections of antimicrobially active compounds ("antibiotics") in surface waters have been reported. As a possible input pathway in most cases municipal sewage has been discussed. But as an input from the realm of agriculture is conceivable as well, in this study it should be investigated if an input can occur via the pathway application of liquid manure on fields with the subsequent mechanisms surface run-off/interflow, leaching, and drift. For this purpose a series of surface waters, soils, and liquid manures from North Rhine-Westphalia (Northwestern Germany) were sampled and analyzed for up to 29 compounds by HPLC-MS/MS. In each of the surface waters antibiotics could be detected. The highest concentrations were found in samples from spring (300 ng/L of erythromycin). Some of the substances detected (e.g., tylosin), as well as characteristics in the landscape suggest an input from agriculture in some particular cases. In the investigation of different liquid manure samples by a fast immunoassay method sulfadimidine could be detected in the range of 1...2 mg/kg. Soil that had been fertilized with this liquid manure showed a content of sulfadimidine extractable by accelerated solvent extraction (ASE) of 15 ??g/kg dry weight even 7 months after the application. This indicates the high stability of some antibiotics in manure and soil.

Christian, T.; Schneider, R. J.; Farber, H. A.; Skutlarek, D.; Meyer, M. T.; Goldbach, H. E.

2003-01-01

349

The Character of the Solar Wind, Surface Interactions, and Water  

NASA Technical Reports Server (NTRS)

We discuss the key characteristics of the proton-rich solar wind and describe how it may interact with the lunar surface. We suggest that solar wind can be both a source and loss of water/OH related volatiles, and review models showing both possibilities. Energy from the Sun in the form of radiation and solar wind plasma are in constant interaction with the lunar surface. As such, there is a solar-lunar energy connection, where solar energy and matter are continually bombarding the lunar surface, acting at the largest scale to erode the surface at 0.2 Angstroms per year via ion sputtering [1]. Figure 1 illustrates this dynamically Sun-Moon system.

Farrell, William M.

2011-01-01

350

Sensors and OBIA synergy for operational monitoring of surface water  

NASA Astrophysics Data System (ADS)

This contribution will focus on combining Object Based Image Analysis (i.e. OBIA with e-Cognition 8) and recent sensors (i.e. Spot 5 XS, Pan and ALOS Prism, Avnir2, Palsar) to address the technical feasibility for an operational monitoring of surface water. Three cases of river meandering (India), flood mapping (Nepal) and dam's seasonal water level monitoring (Morocco) using recent sensors will present various application of surface water monitoring. The operational aspect will be demonstrated either by sensor properties (i.e. spatial resolution and bandwidth), data acquisition properties (i.e. multi sensor, return period and near real-time acquisition) but also with OBIA algorithms (i.e. fusion of multi sensors / multi resolution data and batch processes). In the first case of river meandering (India) we will address multi sensor and multi date satellite acquisition to monitor the river bed mobility within a floodplain using an ALOS dataset. It will demonstrate the possibility of an operational monitoring system that helps the geomorphologist in the analysis of fluvial dynamic and sediment budget for high energy rivers. In the second case of flood mapping (Nepal) we will address near real time Palsar data acquisition at high spatial resolution to monitor and to map a flood extension. This ALOS sensor takes benefit both from SAR and L band properties (i.e. atmospheric transparency, day/night acquisition, low sensibility to surface wind). It's a real achievement compared to optical imagery or even other high resolution SAR properties (i.e. acquisition swath, bandwidth and data price). These advantages meet the operational needs set by crisis management of hydrological disasters but also for the implementation of flood risk management plans. The last case of dam surface water monitoring (Morocco) will address an important issue of water resource management in countries affected by water scarcity. In such countries water users have to cope with over exploitation, frequent drought period and now with foreseen climate change impacts. This third case will demonstrate the efficiency of SPOT 5 programming in synergy with OBIA methodology to assess the evolution of dam surface water within a complete water cycle (i.e. 2008-09). In all those three cases image segmentation and classification algorithms developed with e-Cognition 8 software allow an easy to use implementation of simple to highly sophisticate OBIA rulsets fully operational in batch processes. Finally this contribution foresees the new opportunity of integration of Worldview 2 multispectral imagery (i.e. 8 bands) including its "coastal" band that will also find an application in continental surface water bathymetry. Worldview 2 is a recently launch satellite (e.g. October 2009) that starts to collect earth observation data since January 2010. It is therefore a promising new remote sensing tool to develop operational hydrology in combination high resolution SAR imagery and OBIA methodology. This contribution will conclude on the strong potential for operationalisation in hydrology and water resources management that recent and future sensors and image analysis methodologies are offering to water management and decision makers.

Masson, Eric; Thenard, Lucas

2010-05-01

351

MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation  

NASA Astrophysics Data System (ADS)

The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterisations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude ( Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiation balance. The evaporation rate of water is calculated by an expression for free convection, driven by density differences between water vapor and ambient air, the condensation rate follows from the assumption that any water vapour which exceeds the local saturation pressure condenses instantly, and atmospheric transport of water vapour is approximated by instantaneous mixing. Glacial flow of ice deposits is neglected. Simulations with constant orbital parameters show that low obliquities favour deposition of ice in high latitudes and vice versa. A transient scenario driven by a computed history of orbital parameters over the last 10 million years produces essentially monotonically growing polar ice deposits during the most recent 4 million years, and a very good agreement with the observed present-day polar layered deposits. The thick polar deposits sometimes continue in thin ice deposits which extend far into the mid latitudes, which confirms the idea of "ice ages" at high obliquity.

Greve, R.; Grieger, B.; Stenzel, O. J.

2010-05-01

352

Theoretical investigation of water formation on Rh and Pt Surfaces  

NASA Astrophysics Data System (ADS)

Catalytic water formation from adsorbed H and O adatoms is a fundamental reaction step in a variety of technologically important reactions involving organic molecules. In particular, the water-formation rate determines the selectivity of the catalytic partial oxidation of methane to syngas. In this report we present a theoretical investigation of the potential-energy diagram for water formation from adsorbed O and H species on Rh(111) and Pt(111) surfaces. The study is based on accurate first-principles calculations applying density-functional theory. Our results are compared to the potential-energy diagram for this reaction inferred from experimental data by Hickman and Schmidt [AIChE. J. 39, 1164 (1993)]. The calculations essentially reproduce the scheme of Hickman and Schmidt for water formation on Rh(111) with the important difference that the OH molecule is significantly more stable than assumed by Hickman and Schmidt. On Pt(111) surfaces, however, the calculations predict a barrier to OH formation very similar to that found on Rh(111). In particular, the calculated barrier to OH formation of about 20 kcal/mol seems to contradict the small 2.5 kcal/mol barrier assumed in the Hickman-Schmidt scheme and the observed large rate of water formation on Pt. A possible explanation for the apparent discrepancy between the large calculated barrier for OH formation on Pt and the experimentally observed rapid formation of water even at low temperatures is that the active sites for water formation on Pt are at ``defect'' sites and not on the ideally flat terraces. A similar conclusion has been reached by Verheij and co-workers [Surf. Sci. 371, 100 (1997); Chem. Phys. Lett. 174, 449 (1990); Surf. Sci. 272, 276 (1991)], who did detailed experimental work on water formation on Pt surfaces. Analyzing our results, we develop an explicit picture of the interaction processes governing the formation of OH groups. This picture rationalizes the calculated weak dependence of OH formation on substrate material. An important conclusion from this work is that ``good'' catalysts for the partial oxidation of hydrocarbons should resist defect formation at their surfaces.

Wilke, Steffen; Natoli, Vincent; Cohen, Morrel H.

2000-06-01

353

Effects of Molluscicidal Constituents in Spices on Reproduction in Snails  

Microsoft Academic Search

Sublethal treatment (20% and 60% of 24 hr LC50) of young snails (Lymnaea acuminata) with the active molluscicidal constituents ferulic acid and umbelliferone from Ferula asafoetida, eugenol from Syzygium aromaticum, and limonene from Carum carvi caused a significant reduction in the fecundity, hatchability, and survival of the snails. Treatment with the constituents also increased the length of time to hatching

Pradeep Kumar; Vinay K. Singh; Chandra P. M. Tripathi; Dinesh K. Singh

2010-01-01

354

Outgrowths from Pieces of Helix aspersa, the Common Snail  

Microsoft Academic Search

IN connexion with a cytological problem now being investigated, an attempt has been made to culture snail tissue. It is well known that snails are able to repair extensive injuries under what must be extremely septic conditions. The epithelium beneath the shell and elsewhere is not keratinised or otherwise protected, except perhaps for its faculty to produce mucus. It follows

J. Brontë Gatenby

1931-01-01

355

Soil Moisture: The Hydrologic Interface Between Surface and Ground Waters  

NASA Technical Reports Server (NTRS)

A hypothesis is presented that many hydrologic processes display a unique signature that is detectable with microwave remote sensing. These signatures are in the form of the spatial and temporal distributions of surface soil moisture. The specific hydrologic processes that may be detected include groundwater recharge and discharge zones, storm runoff contributing areas, regions of potential and less than potential evapotranspiration (ET), and information about the hydrologic properties of soils. In basin and hillslope hydrology, soil moisture is the interface between surface and ground waters.

Engman, Edwin T.

1997-01-01

356

Damage potential of the golden apple snail Pomacea canaliculata (Lamarck) in irrigated rice and its control by cultural approaches  

Microsoft Academic Search

The damage caused by the golden apple snail in rice seedlings of various ages was assessed for different pest densities and water depth regimes. The experiments involved randomized complete-block and split-split plot designs with three replications. Water depth accounted for a higher proportion of the damage than seedlings' age and pest densities. At a water depth of >5.0 cm, direct-seeded

Teo Su Sin

2003-01-01

357

Phenotypic Plasticity of the Introduced New Zealand Mud Snail, Potamopyrgus antipodarum, Compared to Sympatric Native Snails  

PubMed Central

Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16°C and 22°C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species.

Levri, Edward P.; Krist, Amy C.; Bilka, Rachel; Dybdahl, Mark F.

2014-01-01

358

How much surface water can gilgai microtopography capture?  

NASA Astrophysics Data System (ADS)

Gilgai microtopography is associated with landscapes of strongly shrinking-swelling soils (Vertisols) and affects spatial and temporal variability of runoff, and thus the generation of stream flow and plant-available water. However, no report is available on the amount of surface water that a landscape with gilgai depressions can retain. Our objective was to assess water capturing capacity of a typical Vertisol landscape with gilgai depressions in the Blackland Prairie Major Land Resource Area of Texas. The 45 by 40 m study site was located on a Vertisol with circular gilgai covered by improved pasture on a summit with slope of less than 3%. A digital elevation model (DEM) with 0.25 m2 cell size was created from elevation data acquired by using GPS. Water capturing capacity of gilgai depressions was estimated at 10 randomly selected local gilgai basins by analyzing spatial distribution of Topographic Wetness Index (TWI). Our findings indicate that the average circular gilgai depression can hold 0.78 m3 of water leading to an estimate of 0.024 m3 m-2 water capturing capacity in a circular gilgai landscape, assuming no infiltration. The gilgai could capture a maximum of 43.74 m3 of rain and runoff water at the 1800 m2 study site. Consequently, if the soil were saturated and not infiltrating any water, no runoff would be expected following a 24.3 mm m-2, 1 h precipitation, affecting estimates of streamflow (runoff) and plant available water (redistribution and infiltration) at the m to km scale.

Kishné, A. Sz.; Morgan, C. L. S.; Neely, H. L.

2014-05-01

359

Protonation of water clusters induced by hydroperoxyl radical surface adsorption.  

PubMed

We have investigated the HO(2) adsorption and acid dissociation process on the surface of (H(2)O)(20) and (H(2)O)(21) clusters by using quantum-chemistry calculations. Our results show that the radical forms a stable hydrogen-bond complex on the cluster. The HO(2) acid dissociation is more favorable in the case of the (H(2)O)(21) cluster, for which the inner water molecule plays a crucial role. In fact, acid dissociation of HO(2) is found to occur in two steps. The first step involves H(2) O autoionization in the cluster, and the second one involves the proton transfer from the HO(2) radical to the hydroxide anion. The presence of the HO(2) radicals on the surface of the cluster facilitates water autoionization in the cluster. PMID:21433120

Torrent-Sucarrat, Miquel; Ruiz-Lopez, Manuel F; Martins-Costa, Marilia; Francisco, Joseph S; Anglada, Josep M

2011-04-26

360

Water ice polymorphs and their significance on planetary surfaces  

NASA Technical Reports Server (NTRS)

Impacts into an icy surface could produce significant amounts of high pressure forms of water ice. Due to the relatively low ambient surface temperatures on satellites in the outer solar system and the modest temperature rises accompanying the impact pressures required for water ice metamorphism, high-pressure polymorphs will be created by and may remain after large cratering events. If so, those high-pressure ices should be ubiquitous. Low-pressure cubic ice may be abundant as well. Impacts into an icy regolith may both produce high-pressure polymorphs from ice I and destroy high-pressure polymorphs already present. The result will be an (unknown) equilibrium concentration of high pressure polymorphs in the regolith. Polymorphs may be detectable and mappable by reflection spectroscopy at vacuum ultraviolet and mid-infrared wavelengths.

Gaffney, E. S.; Matson, E. L.

1980-01-01

361

Regularity of Traveling Free Surface Water Waves with Vorticity  

NASA Astrophysics Data System (ADS)

We prove real analyticity of all the streamlines, including the free surface, of a gravity- or capillary-gravity-driven steady flow of water over a flat bed, with a Hölder continuous vorticity function, provided that the propagating speed of the wave on the free surface exceeds the horizontal fluid velocity throughout the flow. Furthermore, if the vorticity possesses some Gevrey regularity of index s, then the stream function of class C 2, ? admits the same Gevrey regularity throughout the fluid domain; in particular if the Gevrey index s equals 1, then we obtain analyticity of the stream function. The regularity results hold not only for periodic or solitary-water waves, but also for any solution to the hydrodynamic equations of class C 2, ? .

Chen, Hua; Li, Wei-Xi; Wang, Ling-Jun

2013-12-01

362

Impact of river restoration on groundwater - surface water - interactions  

NASA Astrophysics Data System (ADS)

Since the end of the 19th century, flood protection was increasingly based on the construction of impermeable dams and side walls (BWG, 2003). In spite of providing flood protection, these measures also limited the connectivity between the river and the land, restricted the area available for flooding, and hampered the natural flow dynamics of the river. Apart from the debilitating effect on riverine ecosystems due to loss of habitats, these measures also limited bank filtration, inhibited the infiltration of storm water, and affected groundwater-surface water-interactions. This in turn had a profound effect on ecosystem health, as a lack of groundwater-surface water interactions led to decreased cycling of pollutants and nutrients in the hyporheic zone and limited the moderation of the water temperature (EA, 2009). In recent decades, it has become apparent that further damages to riverine ecosystems must be prohibited, as the damages to ecology, economy and society surmount any benefits gained from exploiting them. Nowadays, the restoration of rivers is a globally accepted means to restore ecosystem functioning, protect water resources and amend flood protection (Andrea et al., 2012; Palmer et al., 2005; Wortley et al., 2013). In spite of huge efforts regarding the restoration of rivers over the last 30 years, the question of its effectiveness remains, as river restorations often reconstruct a naturally looking rather than a naturally functioning stream (EA, 2009). We therefore focussed our research on the effectiveness of river restorations, represented by the groundwater-surface water-interactions. Given a sufficiently high groundwater level, a lack of groundwater-surface water-interactions after restoration may indicate that the vertical connectivity in the stream was not fully restored. In order to investigate groundwater-surface water-interactions we determined the thermal signature on the stream bed and in +/- 40 cm depth by using Distributed Temperature Sensing (DTS), a fibre optical method for temperature determination over long distances (Selker et al., 2006). Thermal signatures were determined in a small urban stream before and after restoration and compared to streams in natural and near-natural settings. BWG BUNDESAMT FÜR WASSER UND GEOLOGIE, 2003. Die Geschichte des Hochwasserschutzes in der Schweiz. Bericht des BWG, Serie Wasser. Biel. 208 p. EA ENVIRONMENT AGENCY (UK), 2009. The Hyporheic Handbook: A handbook on the groundwater-surface water interface and hyporheic zone for environment managers. Bristol. 280 p. ANDREA, F., GSCHÖPF, C., BLASCHKE, A.P., WEIGELHOFER, G., AND RECKENDORFER, W., 2012. Ecological niche models for the evaluation of management options in urban floodplain - conservation vs. restoration purposes. Environ. Sci. Policy, http://dx.doi.org/10.1016/j.envsci.2012.08.011. PALMER, M.A., BERNHARDT, E.S., ALLAN, J.D., LAKE, P.S., ALEXANDER, G., BROOKS, S., CARR, J., CLAYTON, S., DAHM, C.N., FOLLSTAD SHAH, J., GALAT, D.L., LOSS, S.G., GOODWIN, P., HART, D.D., HASSETT, B., JENKINSON, R., KONDOLF, G.M., LAVE, R., MEYER, J.L., O`DONNELL, T.K., PAGANO, L. AND SUDDUTH, E., 2005. Standards for ecologically successful river restoration. Journal of Applied Ecology, 42, pp. 208 - 217. DOI 10.1111/j.1365-2664.2005.01004.x. WORTLEY, L., HERO, J-M., HOWES, M., 2013. Evaluating Ecological Restoration Success: A Review of the Literature. Restoration Ecology, 21 (5), pp. 537 - 543. DOI 10.1111/rec.12028. SELKER, J.S., THEVENAZ, L., HUWALD, H., MALLET, A., LUXEMBURG, W., VAN DE GIESEN, N., STEJSKAL, M., ZEMAN, J., WESTHOFF, M., AND PARLANGE, M.B., 2006. Distributed fibre-optic temperature sensing for hydrologic systems. Water Resources Research, 42(12), W12202.

Kurth, Anne-Marie; Schirmer, Mario

2014-05-01

363

Utilizing an Automated Home-Built Surface Plasmon Resonance Apparatus to Investigate How Water Interacts with a Hydrophobic Surface  

NASA Astrophysics Data System (ADS)

By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low- density region forms near the surface. We have employed an automated home-built Surface Plasmon Resonance (SPR) apparatus to investigate this boundary.

Poynor, Adele

2011-03-01

364

Experimental Study of Fine Structures of Wind - Water Surface.  

NASA Astrophysics Data System (ADS)

A two-dimensional Scanning Laser Slope Gauge (SLSG) was developed to measure the slopes of water surface covered with ripples. Measurements under fourteen wind velocities from 1 to 10 m s^{-1} were performed in the Wind-Wave-Current Research Facility to study the fine structure of water surface. Wavenumber slope spectra in the wavelength range from 4.5 to 81 mm were obtained. These spectra at light, medium and high winds are observed to have different features, indicating that the energy balance of short waves is dominated by different physical processes. At 1-m s^ {-1} wind velocity, a spectral peak in the omnidirectional wavenumber slope spectrum at about lambda = 3.5 cm was observed corresponding to initial wind waves, where lambda is the wavelength. A 'dip' in the spectra near lambda = 1.73 cm and a cutoff of capillary waves starting at lambda = 0.87 cm were observed at medium winds. At high winds, the spectral density was observed to saturate. Based on the observed wavenumber slope spectra, the power laws in wavenumber and wind dependence of wavenumber spectrum are proposed. It is found that the exponents of the power laws are not constant. Spatial features of the wind-disturbed water surface under different wind velocities were observed. Streaks parallel to the wind direction were first observed at low wind speeds. Parasitic capillary waves characterized by a sharp trough and flat crest were observed to be the dominant ripple patterns at medium wind speeds. Structures caused by breaking waves are more common at high wind speeds. The probability density distributions of crosswind slopes and curvatures of the water surface can be represented by Gaussian distributions, while that of upwind-downwind slopes deviate from the Gaussian but can be described by a Gram-Charlier series. Joint probability density functions of slopes and curvatures are examined for the first time. A series of Chi-square tests indicated that the jointed Gaussian model cannot represent the observed joint distribution well. The joint distributions of slopes and curvatures are valuable not only for the description of ocean surface waves, but also for understanding of microwave backscattering from the wind-disturbed water surface.

Zhao, Meng

365

Water molecule adsorption properties on BiVO4 surface  

Microsoft Academic Search

The behavior of water molecules on the (100) surface of BiVO4 has been investigated using first-principles molecular dynamics in view of the crucial role in photo catalytic activities under visible light irradiation. The simulations show that H2O molecules are adsorbed in a non-dissociated molecular form on the fivefold coordinated Bi site. The adsorption energy was estimated to be ~0.58 eV\\/molecule

M. Oshikiri; M. Boero; A. Matsushita; J. Ye

2006-01-01

366

Pre-coagulation for microfiltration of an upland surface water  

Microsoft Academic Search

The effect of different coagulants on cake formation and hydraulic resistance in membrane filtration of strongly coloured (SUVA?4.8) upland surface water has been studied at bench-scale under constant pressure conditions. Coagulants used were aluminium sulphate, polyaluminium chloride, ferric chloride and ferric sulphate. Optimisation of coagulation parameters was carried by conventional jar testing. The R?c (specific cake resistance in m?2) values

A. T. Pikkarainen; S. J. Judd; J. Jokela; L. Gillberg

2004-01-01

367

Atrazine removal by ozonation processes in surface waters  

Microsoft Academic Search

Atrazine (6?chloro?N?ethyl?N'?isopropyl?1,3,5?triazinedyl?2,4?diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time

Fernando J. Beltrán; Javier Rivas; Benito Acedo

1999-01-01

368

Lagrange–Galerkin method for unsteady free surface water waves  

Microsoft Academic Search

We present a new numerical technique to approximate solutions to unsteady free surface flows modelled by the two-dimensional shallow water equations. The method we propose in this paper consists of an Eulerian–Lagrangian splitting of the equations along the characteristic curves. The Lagrangian stage of the splitting is treated by a non-oscillatory modified method of characteristics, while the Eulerian stage is

Mohammed Seaïd; Mofdi El-Amrani

2006-01-01

369

Perfluorinated Surfactants in Surface and Drinking Waters (9 pp)  

Microsoft Academic Search

Background, Aim and Scope  \\u000a In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different\\u000a surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported\\u000a ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic

Martin Exner; Harald Färber

2006-01-01

370

Determination of anionic surface-active substances in waters  

Microsoft Academic Search

We have studied sorption on the SDB-L polymer sorbent of anionic surface-active substances (ASAS) of the alkylsulfate class\\u000a with a different length of a hydrocarbon radical and alkylarylsulfonates (sulfanol), methylene blue in the presence and absence\\u000a of ASAS. We have developed the technique of sorption-photometric determination of the latter in waters with determination\\u000a limit, which depends on ASAS hydrophobicity and

S. A. Dolenko; E. Yu. Alekseenko; N. F. Kushchevskaya

2010-01-01

371

Natural annual cycle of heat shock protein expression in land snails: desert versus Mediterranean species of Sphincterochila.  

PubMed

Land snails are subject to daily and seasonal variations in temperature and in water availability, and have evolved annual cycles of activity and aestivation as part of their survival strategy. We tested in the field whether adaptation to different habitats affects the endogenous levels of heat shock proteins (HSPs) in two closely related Sphincterochila snail species, a desiccation-resistant desert species, Sphincterochila zonata, and a Mediterranean-type, desiccation-sensitive species, S. cariosa. We examined HSP levels in various tissues of snails during aestivation and after resumption of activity. Our study shows that, during aestivation, S. cariosa had higher standing stocks of Hsp70 in the foot and the hepatopancreas, and of small HSPs (sHSPs) in all the examined tissues, whereas S. zonata had higher stocks of Hsp70 in the kidney and of Hsp90 in the kidney and in the hepatopancreas. Arousal induced a general upregulation of HSPs, except for Hsp90, the expression of which in the foot was higher during aestivation. We suggest that the stress protein machinery is upregulated during arousal in anticipation of possible oxidative stress ensuing from the accelerating metabolic rate and the exit from the deep hypometabolic state. Our findings support the concept that, in land snails, aestivation and activity represent two distinct physiological states, and suggest that land snails use HSPs as important components of the aestivation mechanism, and as part of their survival strategy during and after arousal. Our study also indicates that adaptation to different habitats results in the development of distinct strategies of HSP expression with likely consequences for the ecology and distribution of land snails. PMID:20889829

Arad, Zeev; Mizrahi, Tal; Goldenberg, Shoshana; Heller, Joseph

2010-10-15

372

Mechanical Balance Laws for Boussinesq Models of Surface Water Waves  

NASA Astrophysics Data System (ADS)

Depth-integrated long-wave models, such as the shallow-water and Boussinesq equations, are standard fare in the study of small amplitude surface waves in shallow water. While the shallow-water theory features conservation of mass, momentum and energy for smooth solutions, mechanical balance equations are not widely used in Boussinesq scaling, and it appears that the expressions for many of these quantities are not known. This work presents a systematic derivation of mass, momentum and energy densities and fluxes associated with a general family of Boussinesq systems. The derivation is based on a reconstruction of the velocity field and the pressure in the fluid column below the free surface, and the derivation of differential balance equations which are of the same asymptotic validity as the evolution equations. It is shown that all these mechanical quantities can be expressed in terms of the principal dependent variables of the Boussinesq system: the surface excursion ? and the horizontal velocity w at a given level in the fluid.

Ali, Alfatih; Kalisch, Henrik

2012-06-01

373

ERTS imagery applied to Alaskan coastal problems. [surface water circulation  

NASA Technical Reports Server (NTRS)

Along the Alaska coast, surface water circulation is relatively easy to study with ERTS imagery. Highly turbid river water, sea ice, and fluvial ice have proven to be excellent tracers of the surface waters. Sea truth studies in the Gulf of Alaska, Cook Inlet, Bristol Bay, and the Bering Strait area have established the reliability of these tracers. ERTS imagery in the MSS 4 and 5 bands is particularly useful for observing lower concentrations of suspended sediment, while MSS 6 data is best for the most concentrated plumes. Ice features are most clearly seen on MSS 7 imagery; fracture patterns and the movement of specific floes can be used to map circulation in the winter when runoff is restricted, if appropriate allowance is made for wind influence. Current patterns interpreted from satellite data are only two-dimensional, but since most biological activity and pollution are concentrated near the surface, the information developed can be of direct utility. Details of Alaska inshore circulation of importance to coastal engineering, navigation, pollution studies, and fisheries development have been clarified with satellite data. ERTS has made possible the analysis of circulation in many parts of the Alaskan coast.

Wright, F. F.; Sharma, G. D.; Burbank, D. C.; Burns, J. J.

1974-01-01

374

Black Rat ( Rattus rattus ) Predation on Nonindigenous Snails in Hawai‘i: Complex Management Implications 1  

Microsoft Academic Search

Understanding interactions among nonindigenous species that pose a threat to native species is crucial to effectively preserve native biodiversity. Cap- tive feeding trials demonstrated that the black rat, Rattus rattus, will readily con- sume two of the most destructive nonindigenous snails, the giant African snail, Achatina fulica (100% predation), and the predatory snail Euglandina rosea (80% predation). Rats consumed snails

Wallace M. Meyer; Aaron B. Shiels

2009-01-01

375

Sea ice and surface water circulation, Alaskan continental shelf  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Sediments contributed by the Copper River in the Gulf of Alaska are carried westward along the shore as a distinct plume. Oceanic water relatively poor in suspended material appears to intrude near Montague Island, and turbid water between Middleton Island and Kayak Island is the result of Ekman between transport. An anticlockwise surface water circulation is observed in this region. Ground truth data indicate striking similarity with ERTS-1 imagery obtained on October 12, 1972. Observations of ERTS-1 imagery reveal that various characteristics and distribution of sea ice in the Arctic Ocean can be easily studied. Formation of different types of sea ice and their movement is quite discrenible. Sea ice moves parallel to the cost in near shore areas and to the northerly direction away from the coast.

Wright, F. F. (principal investigator); Sharma, G. D.; Burns, J. J.

1973-01-01

376

Surface hydrophobicity of culture and water biofilm of Penicillium spp.  

PubMed

Fungal surface hydrophobicity is involved in several functions in fungal growth and development. Water contact angles measurement has been used as a direct and simple approach for its characterisation in solid cultures. Microsphere adhesion assay is said to be the best method to assess cell hydrophobicity of filamentous fungi. This study aimed to apply these two methods to study hydrophobicity of Penicillium expansum and Penicillium brevicompactum grown as mycelial mats in solid culture, liquid culture and water biofilms. As result, both species in solid cultures were classified as hydrophobic with contact angles ?90º, but in liquid cultures and water biofilms showed different levels of hydrophobicity when microsphere adhesion assay was applied. In addition, was found that biofilms have specific hydrophobic hyphae which may be involved in fungal ecological functions. PMID:22011877

Siqueira, Virginia; Lima, Nelson

2012-02-01

377

DEVELOPMENT OF GIARDIA C.T VALUES FOR THE SURFACE WATER TREATMENT RULE  

EPA Science Inventory

As a consequence of the 1986 Amendments to the Safe Drinking Water Act (SDWA) the U.S. EPA has issued a Surface Water Treatment Rule (SWTR) for systems using surface and ground waters under the direct influence of surface water. n the Guidance Manual of the SWTR, the EPA recommen...

378

Effect of Radiant Energy on Near-Surface Water  

PubMed Central

While recent research on interfacial water has focused mainly on the few interfacial layers adjacent to the solid boundary, century-old studies have extensively shown that macroscopic domains of liquids near interfaces acquire features different from the bulk. Interest in these long-range effects has been rekindled by recent observations showing that colloidal and molecular solutes are excluded from extensive regions next to many hydrophilic surfaces [Zheng and Pollack Phys. Rev. E 2003, 68, 031408]. Studies of these aqueous “exclusion zones” reveal a more ordered phase than bulk water, with local charge separation between the exclusion zones and the regions beyond [Zheng et al. Colloid Interface Sci. 2006, 127, 19; Zheng and Pollack Water and the Cell: Solute exclusion and potential distribution near hydrophilic surfaces; Springer: Netherlands, 2006; pp 165–174], here confirmed using pH measurements. The main question, however, is where the energy for building these charged, low-entropy zones might come from. It is shown that radiant energy profoundly expands these zones in a reversible, wavelength-dependent manner. It appears that incident radiant energy may be stored in the water as entropy loss and charge separation.

Chai, Binghua; Yoo, Hyok; Pollack, Gerald H.

2010-01-01

379

Reconnaissance of selected PPCP compounds in Costa Rican surface waters.  

PubMed

Eighty-six water samples were collected in early 2009 from Costa Rican surface water and coastal locations for the analysis of 34 pharmaceutical and personal care product compounds (PPCPs). Sampling sites included areas receiving treated and untreated wastewaters, and urban and rural runoff. PPCPs were analyzed using a combination of solid phase extraction and liquid chromatography tandem mass spectrometry. The five most frequently detected compounds were doxycycline (77%), sulfadimethoxine (43%), salicylic acid (41%), triclosan (34%) and caffeine (29%). Caffeine had the maximum concentration of 1.1 mg L(-1), possibly due to coffee bean production facilities upstream. Other compounds found in high concentrations include: doxycycline (74 ?g L(-1)), ibuprofen (37 ?g L(-1)), gemfibrozil (17 ?g L(-1)), acetominophen (13 ?g L(-1)) and ketoprofen (10 ?g L(-1)). The wastewater effluent collected from an oxidation pond had similar detection and concentrations of compounds compared to other studies reported in the literature. Waters receiving runoff from a nearby hospital showed higher concentrations than other areas for many PPCPs. Both caffeine and carbamazepine were found in low frequency compared to other studies, likely due to enhanced degradation and low usage, respectively. Overall concentrations of PPCPs in surface waters of Costa Rica are inline with currently reported occurrence data from around the world, with the exception of doxycycline. PMID:22048020

Spongberg, Alison L; Witter, Jason D; Acuña, Jenaro; Vargas, José; Murillo, Manuel; Umaña, Gerardo; Gómez, Eddy; Perez, Greivin

2011-12-15

380

Sea, ice and surface water circulation, Alaskan continental shelf  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. ERTS-1 imagery has been extremely useful in understanding the tidal water movements in a large estuary such as Cook Inlet. As more imagery obtained during various tidal stages become available it appears that complex and fast changing micro-circulation patterns develop in various regions of Cook Inlet during each advancing and receding tide. More ERTS-1 synoptic imagery is needed to fully understand the effect of the approach of tidal front on the water movements in the various regions through the estuary. The conventional onboard ship data gathered during various cruises although revealed the overall circulation pattern in Cook Inlet but failed to show micro-subgyres which develop in various regions during each tide which are discernible on ther ERTS-1 imagery. Suspended load distribution in the Bering Sea during summer varies significantly. In areas of phytoplankton bloom and at the river mouths the suspended load is higher than the 1 mg/1 which is found over most areas. The influence of major rivers on temperature, salinity, and suspended load in surface water as well as at shallow depth is apparent. On the Bering shelf a strong pycnocline generally at depth 10-20 m is formed by surface fresh water flow which retains sediment in suspension over extended periods.

Sharma, G. D.; Wright, F. F.; Burns, J. J. (principal investigators)

1973-01-01

381

Input dynamics of pesticide transformation products into surface water  

NASA Astrophysics Data System (ADS)

Some pesticide transformation products have been observed to occur in higher concentrations and more frequently than the parent active pesticide in surface water and groundwater. These products are often more mobile and sometimes more stable than the parent pesticide. If they also represent the major product into which the parent substance is transformed, these transformation products may dominate observed pesticide occurrences in surface water and groundwater. Their potential contribution to the overall risk to the aquatic environment caused by the use of the parent pesticide should therefore not be neglected in chemical risk and water quality assessments. The same is true for transformation products of other compound classes that might reach the soil environment, such as veterinary pharmaceuticals. However, the fate and input pathways of transformation products of soil-applied chemicals into surface water are not yet well understood, which largely prevents their appropriate inclusion into chemical risk and water quality assessments. Here, we studied whether prioritization methods based on available environmental fate data from pesticide registration dossiers in combination with basic fate models could help identify transformation products which can be found in relevant concentrations in surface and groundwater and which should therefore be included into monitoring programs. A three-box steady state model containing air, soil, and surface water compartments was used to predict relative inputs of pesticide transformation products into surface waters based on their physico-chemical and environmental fate properties. The model predictions were compared to monitoring data from a small Swiss river located in an intensely agricultural catchment (90 km2) which was flow-proportionally sampled from May to October 2008 and screened for 74 pesticides as well as 50 corresponding transformation products. Sampling mainly occurred during high discharge, but additional samples during baseflow conditions were also taken. The analytical measurements included solid phase extraction, liquid chromatography and high resolution mass spectrometry (SPE-LC-HR-MS/MS). Quantification was achieved using reference standards and internal standards. Besides the well-known transformation products of triazine and chloroacetanilide herbicides, transformation products of other compound classes such as azoxystrobin acid (from azoxystrobin, strobilurin fungicide), chloridazon-desphenyl and chloridazon-methyl-desphenyl (from chloridazon, pyridazinone herbicide), and metamitron-desamino (from metamitron, triazinone herbicide) were analyzed in surface water. For a selection of widely used pesticides in the catchment, modelled ratios of transformation product versus parent pesticide concentrations were compared to the measured concentration ratios in the river for the application period and for two 2-month periods following application. Concentration ratios agreed within a factor of 10 for all pairs of parent pesticides and transformation products, and for all seasons, with a single exception. The ratio of chloridazon-desphenyl to chloridazon was under-predicted by a factor of approximately 20. The data revealed that chloridazon-desphenyl was also found in elevated concentrations in all baseflow samples, indicating its presence in the groundwater component of the catchment. The same was true for other transformation products (e.g., metamitron-desamino, chloridazon-methly-desphenyl, metolachlor-ESA), but to a lesser degree. Based on baseflow separation of the hydrograph, the concentration ratio estimation model was supplemented with an additional baseflow component. The concentrations in the baseflow component were estimated with a simple leaching relationship that was compared against measured baseflow concentrations and groundwater findings in Switzerland. The final model yielded good agreement for all compounds and is therefore deemed suitable for prioritization of transformation products with a relevant exposure potential. It also clearly indicated the contr

Kern, Susanne; Singer, Heinz; Hollender, Juliane; Schwarzenbach, René P.; Fenner, Kathrin

2010-05-01

382

Occurrence and distribution of polycyclic aromatic hydrocarbons in reclaimed water and surface water of Tianjin, China  

Microsoft Academic Search

Persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work, 16 PAHs included in the US Environmental Protection Agency's (EPA) priority pollutant list were analyzed using solid-phase extraction–gas chromatography–mass spectrometry (SPE–GC–MS) with a selected ion monitoring (SIM) mode. Reclaimed water and surface water sampling was

Zhonghong Cao; Yuqiu Wang; Yongmin Ma; Ze Xu; Guoliang Shi; Yuanyi Zhuang; Tan Zhu

2005-01-01

383

Water-gas-shift reaction on metal nanoparticles and surfaces  

NASA Astrophysics Data System (ADS)

Density functional theory was employed to investigate the water-gas-shift reaction (WGS, CO+H2O-->H2+CO2) on Au29 and Cu29 nanoparticles seen with scanning tunneling microscopy in model Au/CeO2(111) and Cu/CeO2(111) catalysts. Au(100) and Cu(100) surfaces were also included for comparison. According to the calculations of the authors, the WGS on these systems operate via either redox or associative carboxyl mechanism, while the rate-limiting step is the same, water dissociation. The WGS activity decreases in a sequence: Cu29>Cu(100)>Au29>Au(100), which agrees well with the experimental observations. Both nanoparticles are more active than their parent bulk surfaces. The nanoscale promotion on the WGS activity is associated with the low-coordinated corner and the edge sites as well as the fluxionality of the particles, which makes the nanoparticles more active than the flat surfaces for breaking the O-H bond. In addition, the role of the oxide support during the WGS was addressed by comparing the activity seen in the calculations of the authors for the Au29 and Cu29 nanoparticles and activity reported for X/CeO2(111) and X/ZnO(000?)(X=Cu or Au) surfaces.

Liu, Ping; Rodriguez, José A.

2007-04-01

384

Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams  

USGS Publications Warehouse

Summary 1. Nutrient enrichment is a widespread environmental problem in freshwater ecosystems. Eutrophic conditions caused by nutrient enrichment may result in a higher prevalence of infection by trematode parasites in host populations, due to greater resource availability for the molluscan first intermediate hosts. 2. This study examined relationships among land use, environmental variables indicating eutrophication, population density of the pleurocerid snail, Leptoxis carinata, and trematode infections. Fifteen study sites were located in streams within the Shenandoah River catchment (Virginia, U.S.A.), where widespread nutrient enrichment has occurred. 3. Snail population density had a weak positive relationship with stream water nutrient concentration. Snail population density also increased as human activities within stream catchments increased, but density did not continue to increase in catchments where anthropogenic disturbance was greatest. 4. Cercariae from five families of trematodes were identified in L. carinata, and infection rate was generally low (<10%). Neither total infection rate nor the infection rate of individual trematode types showed a positive relationship with snail population density, nutrients or land use. 5. There were statistically significant but weak relationships between the prevalence of infection by two trematode families and physical and biological variables. The prevalence of Notocotylidae was positively related to water depth, which may be related to habitat use by definitive hosts. Prevalence of Opecoelidae had a negative relationship with orthophosphate concentration and a polynomial relationship with chlorophyll a concentration. Transmission of Opecoelid trematodes between hosts may be inhibited by eutrophic conditions. 6. Leptoxis carinata appears to be a useful species for monitoring the biological effects of eutrophication and investigating trematode transmission dynamics in lotic systems.

Ciparis, Serena; Iwanowicz, Deborah D.; Voshell, J. Reese, Jr.

2013-01-01

385

Heat shock proteins and resistance to desiccation in congeneric land snails.  

PubMed

Land snails are subject to daily and seasonal variations in temperature and in water availability and depend on a range of behavioral and physiological adaptations for coping with problems of maintaining water, ionic, and thermal balance. Heat shock proteins (HSPs) are a multigene family of proteins whose expression is induced by a variety of stress agents. We used experimental desiccation to test whether adaptation to different habitats affects HSP expression in two closely related Sphincterochila snail species, a desiccation-resistant, desert species Sphincterochila zonata, and a Mediterranean-type, desiccation-sensitive species Sphincterochila cariosa. We examined the HSP response in the foot, hepatopancreas, and kidney tissues of snails exposed to normothermic desiccation. Our findings show variations in the HSP response in both timing and magnitude between the two species. The levels of endogenous Hsp72 in S. cariosa were higher in all the examined tissues, and the induction of Hsp72, Hsp74, and Hsp90 developed earlier than in S. zonata. In contrary, the induction of sHSPs (Hsp25 and Hsp30) was more pronounced in S. zonata compared to S. cariosa. Our results suggest that land snails use HSPs as part of their survival strategy during desiccation and as important components of the aestivation mechanism in the transition from activity to dormancy. Our study underscores the distinct strategy of HSP expression in response to desiccation, namely the delayed induction of Hsp70 and Hsp90 together with enhanced induction of sHSPs in the desert-dwelling species, and suggests that evolution in harsh environments will result in selection for reduced Hsp70 expression. PMID:19953352

Mizrahi, Tal; Heller, Joseph; Goldenberg, Shoshana; Arad, Zeev

2010-07-01

386

Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters  

NASA Technical Reports Server (NTRS)

Measured biological oxidation rates of methane in near-surface waters of the Cariaco Basin are compared with the diffusional fluxes computed from concentration gradients of methane in the surface layer. Methane fluxes and oxidation rates were investigated in surface waters, at the oxic/anoxic interface, and in deep anoxic waters. It is shown that the surface-waters oxidation of methane is a mechanism which modulates the flux of methane from marine waters to the atmosphere.

Ward, B. B.; Kilpatrick, K. A.; Novelli, P. C.; Scranton, M. I.

1987-01-01

387

Dry in the Water: The Superhydrophobic Water Fern Salvinia – a Model for Biomimetic Surfaces  

Microsoft Academic Search

Over millions of years plant surfaces evolved optimized complex multifunctional interfaces. They fulfill different functions\\u000a in terrestrial plants such as limitation of uncontrolled water loss, protection against various biotic and abiotic influences,\\u000a and they play a role in the attachment of insects. A recent overview on plant surface functions is presented by Jeffree (in\\u000a Riederer, 2006). One of the most

Zdenek Cerman; Boris F. Striffler; Wilhelm Barthlott

388

[Expression of genes encoding defense factors in the snail Planorbarius corneus (Gastropoda, Pulmonata) infested with trematodes].  

PubMed

Because many species of gastropods are intermediate hosts for trematodes, these molluscs are often used as model-organisms in the studies of invertebrate immune system. Revealing of the ways in which the defense factors functioning became possible due to the use of the methods of molecular biology. Contemporary molecular methods allow analyzing the defense factors allocations and levels of their expression. We investigated the expression of genes encoding defense factors in gastropods by the example of the snail Planorbarius corneus from water bodies of the Leningrad Oblast under infestation with trematods. The snails naturally infested with the parthenites of trematode species belonging to the families Strigeidae, Notocotylidae, Plagiorchiidae, and Schistosomatida were used as the experimental sample. Uninfested snails were used as a control sample. Several genes encoding the factors, which have been recently found involved in the anti-trematode defense reactions in pulmonates, were chosen, namely fibrinogen-related protein, C-lectin, calcium-binding protein, and cystatin-like protein. The genes' expression was analyzed on total mRNA samples by the reverse transcription with the polymerase chain reaction. It was shown than expression levels of the genes under consideration are different in uninfested snails and in the snails infested with different trematode species. Thus, in the mollusks infested with the parthenites of Cotylurus sp. and Bilharziella polonica, the expression levels of the genes of all factors under study were increased, while in the infested Notocotylus sp. n Plagiorchis sp., only expression levels of C-lectin and cystatin-like protein were increased. Results of the expression analysis confirm the role of hemocytes and cells of hepatopancreas in the production of humoral defense factors. In the snails infested with trematodes, the expression levels of C-lectin and calcium-binding protein genes are increased in haemocytes, while the genes of fibrinogen-related and cystatin-like proteins are activated in the hepatopancreas. Our data also confirm the role of the factors examined in the anti-trematode defense reactions in pulmonates. PMID:21061590

Prokhorova, E E; Tsymbalenko, N V; Ataev, G L

2010-01-01

389

Surface and Ground Water Quality in Köprüören Basin (Kütahya), Turkey  

NASA Astrophysics Data System (ADS)

In this study, quality of the water resources in Köprüören Basin, located to the west of Kütahya city in western Anatolia, were investigated. The total catchment area of the basin is 275 km2 and it is located upstream of Kütahya and Eski?ehir plains. Therefore, besides 6,000 people residing in the basin, a much larger population will be impacted by the quality of surface and groundwater resources. Groundwater occurs under confined conditions in the limestones of Pliocene units. Groundwater flow is from north to south and south to north towards Kocasu stream, which flows to Enne Dam. The surface and ground water quality in this area are negatively affected by the mining activities. In the northern part of the area, there are coal deposits present in Miocene Tunçbilek formation. Ground waters in contact with the coal deposits contain low concentrations of arsenic (up to 30 µg/l). In the southern part, the only silver deposit of Turkey is present, which is developed in metamorphic basement rocks, Early Miocene volcanics and Pliocene units near Gümü?köy (Gümü? means silver, köy means village in Turkish). The amount of silver manufactured annually in this silver plant is huge and comprises about 1% of the World's Silver Production. The wastes, enriched in cyanide, arsenic, stibnite, lead and zinc, are stored in waste pools and there is extensive leakage of these heavy metals from these pools. Therefore, surface waters, soils and plants in the affected areas contain high concentrations of arsenic, stibnite and lead. The As, Sb, Pb and Zn concentrations are up to 733 µg/l, 158 µg/l, 48 µg/l, and 286 µg/l in surface waters (in dry season), 6180 ppm, 410 ppm, 4180 ppm, 9950 ppm in soils and 809 ppm, 399 ppm, 800 ppm, 2217 ppm in plants, respectively. Today, most of the As, Sb, Pb and Zn are absorbed by the soils and only a small part are dissolved in water. However, conditions might change in future leading to desorption of these contaminants. Therefore, necessary precautions should be undertaken immediately to protect the environment in the area.

Arslan, ?ebnem; Çelik, Mehmet; Erdem Dokuz, U?ur; Abadi Berhe, Berihu

2014-05-01

390

Occurrence of perchlorate in drinking water, groundwater, surface water and human saliva from India.  

PubMed

Perchlorate (ClO(4)(-)), which is used as an oxidizer in jet and rocket fuels, pyrotechnic devices and explosives, is a widespread contaminant in surface waters and groundwater of many countries. Perchlorate is known to affect thyroid function. Despite the compound's widespread occurrence and potential health effects, perchlorate levels in drinking water in India are not known. In this study, water samples collected from 13 locations in six states (n=66), and saliva samples collected from four locations in three states (n=74) in India, were analyzed for perchlorate using high performance liquid chromatography interfaced with tandem mass spectrometry (HPLC-MS/MS). Perchlorate was detected in most (76%) of the water samples analyzed at concentrations above the quantitation limit of 0.02 microg L(-1); concentrations ranged from <0.02 to 6.9 microg L(-1) (mean: 0.42+/-1.1 microg L(-1); median: 0.07 microg L(-1)). Mean concentrations of perchlorate in drinking water, groundwater, bottled water, surface water and rain water were 0.1, 1.0, <0.02, 0.05 and <0.02 microg L(-1), respectively. From a total of 66 water samples analyzed, only three samples contained perchlorate levels above 1 microg L(-1); all three were groundwater samples. Perchlorate was found in the saliva samples analyzed at concentrations above 0.2 microg L(-1) and up to 4.7 microg L(-1) (mean: 1.3+/-1.3 microg L(-1); median: 0.91 microug L(-1)). No remarkable differences in perchlorate concentrations were found among the sampling locations of water or saliva or in subgroups stratified by gender or age. Perchlorate concentrations in water samples from India are one to two orders of magnitude lower than the concentrations reported for the United States. PMID:19328520

Kannan, Kurunthachalam; Praamsma, Meredith L; Oldi, John F; Kunisue, Tatsuya; Sinha, Ravindra K

2009-06-01

391

Water Resources Data North Dakota Water Year 2002 Volume 1. Surface Water  

USGS Publications Warehouse

Water-resources data for the 2002 water year for North Dakota consists of records of discharge, stage, and water quality for streams; contents, stage, and water quality for lakes and reservoirs; and water levels and water quality for ground-water wells. Volume 1 contains records of water discharge for 106 streamflow-gaging stations; stage only for 22 river-stage stations; contents and/or stage for 14 lake or reservoir stations; annual maximum discharge for 35 crest-stage stations; and water-quality for 96 streamflow-gaging stations, 3 river-stage stations, 11 lake or reservoir stations, 8 miscellaneous sample sites on rivers, and 63 miscellaneous sample sites on lakes and wetlands. Data are included for 7 water-quality monitor sites on streams and 2 precipitation-chemistry stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in North Dakota.

Harkness, R. E.; Lundgren, R. F.; Norbeck, S. W.; Robinson, S. M.; Sether, B. A.

2003-01-01

392

Water Resources Data North Dakota Water Year 2001, Volume 1. Surface Water  

USGS Publications Warehouse

Water-resources data for the 2001 water year for North Dakota consists of records of discharge, stage, and water quality for streams; contents, stage, and water quality for lakes and reservoirs; and water levels and water quality for ground-water wells. Volume 1 contains records of water discharge for 103 streamflow-gaging stations; stage only for 20 river-stage stations; contents and/or stage for 13 lake or reservoir stations; annual maximum discharge for 35 crest-stage stations; and water-quality for 94 streamflow-gaging stations, 2 river-stage stations, 9 lake or reservoir stations, 7 miscellaneous sample sites on rivers, and 58 miscellaneous sample sites on lakes and wetlands. Data are included for 9 water-quality monitor sites on streams and 2 precipitation-chemistry stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in North Dakota.

Harkness, R. E.; Berkas, W. R.; Norbeck, S. W.; Robinson, S. M.

2002-01-01

393

Water resources data--North Dakota, water year 2004, volume 1. Surface water  

USGS Publications Warehouse

Water-resources data for the 2004 water year for North Dakota consists of records of discharge, stage, and water quality for streams; contents, stage, and water quality for lakes and reservoirs; and water levels and water quality for ground-water wells. Volume 1 contains records of water discharge for 106 streamflow-gaging stations; stage only for 23 river-stage stations; contents and/or stage for 14 lake or reservoir stations; annual maximum discharge for 31 crest-stage stations; and water-quality for 92 streamflow-gaging stations, 6 river-stage stations, 15 lake or reservoir stations, 22 miscellaneous sample sites on rivers, and 67 miscellaneous sample sites on lakes and wetlands. Data are included for 5 water-quality monitor sites on streams and 2 precipitation-chemistry stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in North Dakota.

Robinson, S. M.; Lundgren, R. F.; Sether, B. A.; Norbeck, S. W.; Lambrecht, J. M.

2005-01-01

394

Water Resources Data North Dakota Water Year 2003, Volume 1. Surface Water  

USGS Publications Warehouse

Water-resources data for the 2003 water year for North Dakota consists of records of discharge, stage, and water quality for streams; contents, stage, and water quality for lakes and reservoirs; and water levels and water quality for ground-water wells. Volume 1 contains records of water discharge for 108 streamflow-gaging stations; stage only for 24 river-stage stations; contents and/or stage for 14 lake or reservoir stations; annual maximum discharge for 32 crest-stage stations; and water-quality for 99 streamflow-gaging stations, 5 river-stage stations, 11 lake or reservoir stations, 8 miscellaneous sample sites on rivers, and 63 miscellaneous sample sites on lakes and wetlands. Data are included for 7 water-quality monitor sites on streams and 2 precipitation-chemistry stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in North Dakota.

Robinson, S. M.; Lundgren, R. F.; Sether, B. A.; Norbeck, S. W.; Lambrecht, J. M.

2004-01-01

395

The Martian surface radiation environment - Influence of higher atmospheric pressure and surface or sub-surface water  

NASA Astrophysics Data System (ADS)

The Noachian epoch (~4.5 - 3.5 billion years ago) is a promising era for a possible emergence of life on Mars. The presence of runoff channels in areas formed during the Noachian suggests that liquid water existed at least sporadically during that time, with liquid water being regarded as a prerequisite for life. To have sustained liquid water, the atmospheric pressure on Noachian Mars must have been significantly higher than in the present. When considering the possibility of life on Noachian Mars, one conceivable restriction is given by the ionizing radiation environment. Using PLANETOCOSMICS- and GEANT4-simulation codes, we calculate the radiation environment on the Martian surface and the resulting radiation exposure for different atmospheric conditions. Here, we present absorbed dose rates resulting from galactic-cosmic-proton and alpha-particle-induced radiation environments, as well as changes of these rates caused by an increase of atmospheric pressure. Furthermore, we analyze which influence the presence of liquid surface water or sub-surface water-ice would have on the radiation environment under these different atmospheric conditions.

Ehresmann, B.; Böhm, E.; Kohler, J.; Martin, C.; Wimmer-Schweingruber, R. F.; Reitz, G.; Hassler, D. M.; Zeitlin, C. J.

2011-12-01

396

CONCEPTUAL DESIGN OF THE SURFACE WATER COMPONENT OF THE NATIONAL WATER QUALITY ASSESSMENT (NAWQA) PROGRAM.  

USGS Publications Warehouse

The US Geological Survey started, in a pilot phase, a program to provide nationally consistent information on the status and trends in the quality of the nation's fresh water. The program also intends to identify and describe the relationships between both the status and trends in water quality as they relate to natural factors, and the history of land-use, and land- and waste-management practices. The program is organized into hydrologically based study units and, for the study of surface water, involves a combination of fixed-station, synoptic and intensive study approaches. Network design considerations are discussed.

Hirsch, Robert, M.

1986-01-01

397

Water resources data for Florida, water year 1992. Volume 1A. Northeast florida surface water. Water-data report (Annual), 1 October 1991-30 September 1992  

SciTech Connect

Water resources data for 1992 water year for northeast Florida include continuous or daily discharge for 140 streams, periodic discharge for 10 streams, miscellaneous discharge for 14 streams, continuous or daily stage for 32 streams, continuous or daily tide stage for 3 sites, periodic stage for 23 streams, peak discharge for 3 stream, and peak stage for 11 streams; continuous or daily elevations for 36 lakes, periodic elevations for 47 lakes; continuous ground-water levels for 75 wells, periodic ground-water levels for 123 wells, and miscellaneous water-level measurements for 864 wells; quality-of-water data for 38 surface-water sites and 66 wells.

Not Available

1993-04-01

398

A new device for collecting time-integrated water samples from springs and surface water bodies  

USGS Publications Warehouse

A new device termed the 'seepage sampler' was developed to collect representative water samples from springs, streams, and other surface-water bodies. The sampler collects composite, time-integrated water samples over short (hours) or extended (weeks) periods without causing significant changes to the chemical composition of the samples. The water sample within the sampler remains at the ambient temperature of the water body and does not need to be cooled. Seepage samplers are inexpensive to construct and easy to use. A sampling program of numerous springs and/or streams can be designed at a relatively low cost through the use of these samplers. Transient solutes migrating through such flow systems, potentially unnoticed by periodic sampling, may be detected. In addition, the mass loading of solutes (e.g., agrichemicals) may be determined when seepage samplers are used in conjunction with discharge measurements.

Panno, S. V.; Krapac, I. G.; Keefer, D. A.

1998-01-01

399

Potential impacts of the invasive flatworm Platydemus manokwari on arboreal snails  

Microsoft Academic Search

The introduction of the snail-eating flatworm Platydemus manokwari (Tricladida: Rhynchodemidae) has been considered a cause of the extinction of native land snails on several Pacific islands.\\u000a Although P. manokwari is known to attack land snails on the ground, whether P. manokwari attacks snails on trees remains unclear. To clarify the effect of P. manokwari on arboreal snails, we examined survival rates of land

Shinji Sugiura; Yuichi Yamaura

2009-01-01

400

Potential impacts of the invasive flatworm Platydemus manokwari on arboreal snails  

Microsoft Academic Search

\\u000a The introduction of the snail-eating flatworm Platydemus manokwari (Tricladida: Rhyn-chodemidae) has been considered a cause of the extinction of native land snails on several Pacific islands.\\u000a Although P. manokwari is known to attack land snails on the ground, whether P. manokwari attacks snails on trees remains unclear. To clarify the effect of P. manokwari on arboreal snails, we examined survival

Shinji Sugiura; Yuichi Yamaura

401

Scaling up ecohydrological processes: Role of surface water flow in water-limited landscapes  

Microsoft Academic Search

In this study, we present a stochastic landscape modeling approach that has the power to transfer and integrate existing information on vegetation dynamics and hydrological processes from the small scale to the landscape scale. To include microscale processes like ecohydrological feedback mechanisms and spatial exchange like surface water flow, we derive transition probabilities from a fine-scale simulation model. We applied

Alexander Popp; Melanie Vogel; Niels Blaum; Florian Jeltsch

2009-01-01

402

Freak waves at the surface of deep water  

NASA Astrophysics Data System (ADS)

In the paper [1] authors applied canonical transformation to water wave equation not only to remove cubic nonlinear terms but to simplify drastically fourth order terms in Hamiltonian. After the transformation well-known but cumbersome Zakharov equation is drastically simplified and can be written in X-space in compact way. This new equation is very suitable for analytic study as well as for numerical simulation At the same time one of the important issues concerning this system is the question of its integrability. The first part of the work is devoted to numerical and analytical study of the integrability of the equation obtained in [1]. In the second part we present generalization of the improved Zakharov equation for the "almost" 2-D water waves at the surface of deep water. When considering waves slightly inhomogeneous in transverse direction, one can think in the spirit of Kadomtsev-Petviashvili equation for Korteveg-de-Vries equation taking into account weak transverse diffraction. Equation can be written instead of classical variables ?(x,y,t) and ?(x,y,t) in terms of canonical normal variable b(x,y,t). This equation is very suitable for robust numerical simulation. Due to specific structure of nonlinearity in the Hamiltonian the equation can be effectively solved on the computer. It was applied for simulation of sea surface waving including freak waves appearing.

Dyachenko, A. I.; Kachulin, D. I.; Zakharov, V. E.

2014-05-01

403

Freak waves at the surface of deep water  

NASA Astrophysics Data System (ADS)

In the paper ([1]) authors applied canonical transformation to water wave equation not only to remove cubic nonlinear terms but to simplify drastically fourth order terms in Hamiltonian. After the transformation well-known but cumbersome Zakharov equation is drastically simplified and can be written in X-space in compact way. This new equation is very suitable for analytic study as well as for numerical simulation. At the same time one of the important issues concerning this system is the question of its integrability. The first part of the work is devoted to numerical and analytical study of the integrability of the equation obtained in ([1]). In the second part we present generalization of the improved Zakharov equation for the 'almost' 2-D water waves at the surface of deep water. When considering waves slightly inhomogeneous in transverse direction, one can think in the spirit of Kadomtsev-Petviashvili equation for Korteveg-de-Vries equation taking into account weak transverse diffraction. Equation can be written instead of classical variables ?(x,y,t) and ?(x,y,t) in terms of canonical normal variable b(x,y,t). This equation is very suitable for robust numerical simulation. Due to specific structure of nonlinearity in the Hamiltonian the equation can be effectively solved on the computer. It was applied for simulation of sea surface waving including freak waves appearing. References [1] A.I. Dyachenko and V.E. Zakharov, Europ. J. Mech. B 32, 17 (2012)

Kachulin, Dmitriy; Dyachenko, Alexander; Zakharov, Vladimir

2014-05-01

404

Aichi virus in sewage and surface water, the Netherlands.  

PubMed

Detection of Aichi virus in humans was initially reported in Japan in 1989. To establish a timeline for the prevalence of Aichi virus infection among humans in the Netherlands, we conducted molecular analysis of archival water samples from 1987-2000 and 2009-2012. Aichi virus RNA was detected in 100% (8/8) of sewage samples and 100% (7/7) of surface water samples collected during 1987-2000 and 100% (8/8) of sewage samples and 71% (5/7) of surface water samples collected during 2009-2012. Several genotype A and B Aichi virus lineages were observed over the 25-year period studied, but the time course of viral genetic diversity showed recent expansion of the genotype B population over genotype A. Our results show that Aichi virus has been circulating among the human population in the Netherlands since before its initial detection in humans was reported and that genotype B now predominates in this country. PMID:23876456

Lodder, Willemijn J; Rutjes, Saskia A; Takumi, Katsuhisa; de Roda Husman, Ana Maria

2013-08-01

405

Water  

MedlinePLUS

... to groundwater (the fresh water found under the Earth’s surface that supplies wells and springs). Everything that ... body is water. 4. How much of the earth’s surface is water? About 80 percent of the ...

406

SWOT, The Surface Water and Ocean Topography Satellite Mission (Invited)  

NASA Astrophysics Data System (ADS)

Surface fresh water is essential for life, yet we have surprisingly poor knowledge of its variability in space and time. Similarly, ocean circulation fundamentally drives global climate variability, yet the ocean current and eddy field that affects ocean circulation and heat transport at the sub-mesoscale resolution and particularly near coastal and estuary regions, is poorly known. About 50% of the vertical exchange of water properties (nutrients, dissovled CO2, heat, etc) in the upper ocean is taking place at the sub-mesoscale. Measurements from the Surface Water and Ocean Topography satellite mission (SWOT) will make strides in understanding these processes and improving global ocean models for studying climate change. SWOT is a swath-based interferometric-altimeter designed to acquire elevations of ocean and terrestrial water surfaces at unprecedented spatial and temporal resolutions. The mission will provide measurements of storage changes in lakes, reservoirs, and wetlands as well as estimates of discharge in rivers. These measurements are important for global water and energy budgets, constraining hydrodynamic models of floods, carbon evasion through wetlands, and water management, especially in developing nations. Perhaps most importantly, SWOT measurements will provide a fundamental understanding of the spatial and temporal variations in global surface waters, which for many countries are the primary source of water. An on-going effort, the “virtual mission” (VM) is designed to help constrain the required height and slope accuracies, the spatial sampling (both pixels and orbital coverage), and the trade-offs in various temporal revisits. Example results include the following: (1) Ensemble Kalman filtering of VM simulations recover water depth and discharge, reducing the discharge RMSE from 23.2% to 10.0% over an 84-day simulation period, relative to a simulation without assimilation. (2) Ensemble-based data assimilation of SWOT like measurements yields bathymetric slope and depth to within 3.0 microradians and 50 cm, respectively. (3) SWOT measurements of storage changes in lakes larger than 1 km2 will have relative errors generally less than 5% whereas errors for one-hectare size lakes will be about 20%. (4) SWOT estimates of discharge compared to a one-year model-based “truth” data set suggest that instantaneous discharge es