Note: This page contains sample records for the topic water level predictions from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Water Level Prediction with Artificial Neural Network Models  

Microsoft Academic Search

Tide tables are the method of choice for water level predictions in most coastal regions. In the United States, the National Ocean Service (NOS) uses harmonic analysis and time series of previous water levels to compute tide tables. This method is adequate for most locations along the US coast. However, for many locations along the coast of the Gulf of

CARL STEIDLEY; ALEX SADOVSKI; PHILLIPE TISSOT; RAY BACHNAK; ZACK BOWLES

2

Prediction of subsurface water level change from satellite data  

NASA Astrophysics Data System (ADS)

This study explores the potential for predicting the spatial variation in subsurface water level change with crop growth stage from satellite data in Thabua Irrigation Project, situated in the northern central region of Thailand. The relationship between subsurface water level change from pumping water to irrigate rice in the dry season and the age of the rice was analysed. The spatial model of subsurface water level change was developed from the classification using greenness or (normalized difference vegetation index NDVI) derived from Landsat 5 Thematic Mapper data. The NDVI of 52 rice fields was employed to assess its relationship to the age of the rice. It was found that NDVI and rice age have a good correlation (R2 = 0.73). The low NDVI values (-0.059 to 0.082) in these fields were related to the young rice stage (0-30 days). NDVI and subsurface water level change were also correlated in this study and found to have a high correlation (Water level change (m day-1) = 0.3442 × NDVI - 0.0372; R2 = 0.96). From this model, the water level change caused by rice at different growth stages was derived. This was used to show the spatial variation of water level change in the project during the 1998-99 dry-season cropping. This simple method of using NDVI relationships with water level change and crop growth stages proves to be useful in determining the areas prone to excessive lowering of the subsurface water level during the dry season. This could assist in the appropriate planning of the use of subsurface water resources in dry-season cropping.

Saykawlard, Suphan; Honda, Kiyoshi; Das Gupta, Ashim; Eiumnoh, Apisit; Chen, Xiaoyong

2005-03-01

3

Considering rating curve uncertainty in water level predictions  

NASA Astrophysics Data System (ADS)

Streamflow cannot be measured directly and is typically derived with a rating curve model. Unfortunately, this causes uncertainties in the streamflow data and also influences the calibration of rainfall-runoff models if they are conditioned on such data. However, it is currently unknown to what extent these uncertainties propagate to rainfall-runoff predictions. This study therefore presents a quantitative approach to rigorously consider the impact of the rating curve on the prediction uncertainty of water levels. The uncertainty analysis is performed within a formal Bayesian framework and the contributions of rating curve versus rainfall-runoff model parameters to the total predictive uncertainty are addressed. A major benefit of the approach is its independence from the applied rainfall-runoff model and rating curve. In addition, it only requires already existing hydrometric data. The approach was successfully tested on a small urbanized basin in Poland, where a dedicated monitoring campaign was performed in 2011. The results of our case study indicate that the uncertainty in calibration data derived by the rating curve method may be of the same relevance as rainfall-runoff model parameters themselves. A conceptual limitation of the approach presented is that it is limited to water level predictions. Nevertheless, regarding flood level predictions, the Bayesian framework seems very promising because it (i) enables the modeler to incorporate informal knowledge from easily accessible information and (ii) better assesses the individual error contributions. Especially the latter is important to improve the predictive capability of hydrological models.

Sikorska, A. E.; Scheidegger, A.; Banasik, K.; Rieckermann, J.

2013-03-01

4

Predicting Mean Monthly Lake Water Level Using Support Vector Machine  

NASA Astrophysics Data System (ADS)

An experiment on predicting mean monthly lake water level up to 12 month ahead using a recently evolved neural network topology namely support vector machine (SVM) is presented. The support vector machine is firmly based on the theory of statistical learning, which implements a structural risk minimization principle that minimizes the mean square error and an upper bound on the expected risk, as opposed to empirical risk minimization that minimizes the error on the training data only. This has made the support vector training algorithm robust compared to conventional neural network models. The modeling experiment is conducted using historical records of Lake Erie mean monthly water level of 1918 to 2001. The performance of the SVM model is compared with a widely used neural network model called multilayer perceptron (MLP) and with a conventional multiplicative seasonal autoregressive model (SAR) based on correlation coefficients and root mean squared errors performance criteria. Since the ultimate goal concerns the improvement of long-term forecast accuracy, overall, the prediction results show that the proposed method is effective for improving prediction accuracy compared to the MLP and SAR models up to 12 month lead time.

Khan, M.; Coulibaly, P.

2004-05-01

5

Analysis and Predictions on Extreme Coastal Water Levels  

Microsoft Academic Search

Understanding the characteristics of probability distribution of extreme water levels is important for coastal flood mitigation and engineering design. In this study, frequency analysis has been conducted to investigate probability distributions along the coast of the U.S. by using three-parameter General Extreme Value (GEV) method. The GEV model combines three types of probability distributions (Type I for Gumbel distribution, Type

Sudong Xu

2007-01-01

6

Adaptive neuro-fuzzy inference system for prediction of water level in reservoir  

Microsoft Academic Search

Accurate prediction of the water level in a reservoir is crucial to optimizing the management of water resources. A neuro-fuzzy hybrid approach was used to construct a water level forecasting system during flood periods. In particular, we used the adaptive network-based fuzzy inference system (ANFIS) to build a prediction model for reservoir management. To illustrate the applicability and capability of

Fi-John Chang; Ya-Ting Chang

2006-01-01

7

An Investigation of Water Level Prediction in Urban Drainage System Using Artificial Neural Networks  

NASA Astrophysics Data System (ADS)

The pumping stations are the major hydraulic facilities for the elimination of flood in highly developed cities and therefore play an important role in flood mitigation in metropolitan area. Accurate predictions of inner water level in urban drainage systems are necessary and important for successful operation of pumping stations. In view of the characteristics of artificial neural networks (ANNs), the model was introduced in this study for extracting rainfall-water level patterns from torrential rain events. The Yu-Cheng pumping station, Taipei city, is used as a case study, where historical records which contain information of rainfall amounts and inner water levels are used to train and verify the ANN's performance. First, we directly construct the ANN for multistep ahead water level predictions by using 11 storm events at gauging sites. The optimal structure and parameters are then tested via 3 different events. Second, the storm water management model (SWMM) was utilized for the purpose of generating data at un-gauged sites. Data generated from SWMM were further used to train the ANN. Finally, a comparison of water level prediction between SWMM and ANN are given. Our preliminary results show that the ANN is capable of constructing accurate and reliable water level prediction. The results also exemplify the need for a detailed investigation on SWMM-derived error that could propagate the input error into the ANN models.

Chang, F.; Chiang, Y.; Chiu, Y.; Ho, Y.; Chang, L.; Wang, Y.

2008-12-01

8

Using an Artificial Neural Network to Improve Predictions of Water Levels Where Tide Charts Fail  

Microsoft Academic Search

\\u000a Tide tables are the method of choice for water level predictions in most coastal regions. In the United States, the National\\u000a Ocean Service (NOS) uses harmonic analysis and time series of previous water levels to compute tide tables. This method is\\u000a adequate for most locations along the US coast. However, for many locations along the coast of the Gulf of

Carl Steidley; Alexey L. Sadovski; Philippe Tissot; Ray Bachnak; Zack Bowles

2005-01-01

9

Combination of Tank Model and Reservoir Routing for predicting water level at Wonogiri Dam  

NASA Astrophysics Data System (ADS)

Water level predicting model is one of model to support the reservoir operation. This paper, discusses the results of research on the use of tank model combined with reservoir routing to predict the water level of Wonogiri Dam. Tank model was constructed consisting of 2 tank model structured the series, parallel, and parallel-series and 3 models composed tank series and parallel. The objective of this modeling is to obtain the values of tank model parameters are calibrated with measurement data to predict the reservoir water level. Water level measurement at Wonogiri Dam is only done in spillway location and no water level measurement in the cross-section of the rivers before entering the reservoir. Therefore, combining equations of tanks model and reservoir routing is needed so that the hydrograph outflow generated by the tank model become an input of the routing reservoir and will produce an output of the reservoir water level. The data used in this modeling is the daily rainfall data, climatology, elevation-storage curve, daily average water level in reservoir and daily average discharge outflow from reservoir. Genetic Algorithm is used to optimize the parameters of the model to generate predictions of water level close to the measurement during the calibration process. The results of the model are evaluated by calculating the Root Mean Square Error (RMSE) and Coefficient of Efficiency (COE) between the predictions and observations. Calibration results obtained that the best model is the model of the architecture comprises a series of 3 tanks and the parameters k1 = 8,340, k2 = 1.006, k3 = 0.158, k4 = 2.275, k5 = 3.887, k6 = 0.063, d1 = 176.387, d2 = 81.445, d3 = 21.973, s1 = 46.631, s2 = 7.095 , s3 = 5.708, which generate RMSE = 1.260 m and COE = 0.669. While the verification, is obtained the RMSE = 0.878 m and COE = 0.599. The parameter of k4 is the most sensitive parameter that will affect to the performance of the model. Keywords: tank model, reservoir routing, water level predicting, Wonogiri Dam

Lasminto, Umboro; Yudhistira, Yuddi

2010-05-01

10

A reactor water level and pressure prediction method under small loss-of-coolant-accident conditions in boiling water reactors  

Microsoft Academic Search

An on-line method of predicting reactor water level and pressure under small loss-of-coolant-accident (LOCA) conditions has been proposed. The method features initialization of a simplified reactor model in transient conditions. This is done by using plant data in time series and estimating unknown parameters, such as break area, by a nonlinear optimization method. Off-line simulations were performed for small LOCAs

Y. Ohga; K. Fukunishi

1985-01-01

11

Prediction of water seepage into a geologic repository for high-level radioactive waste  

SciTech Connect

Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada. The repository would be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since infiltrating water will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier, and discuss the implications for the performance assessment of the repository. A semi-analytical solution is utilized to determine the complex flow processes in the hot rock environment. The solution is applied at several discrete times after emplacement, covering the time period of strongly elevated temperatures at Yucca Mountain.

Birkholzer, Jens; Mukhophadhyay, Sumit; Tsang, Yvonne

2003-07-07

12

Predicted Ground-Water Levels in the Vicinity of S Area.  

National Technical Information Service (NTIS)

The historical minimum depths to the water table beneath the proposed sites for the DWPF and for the disposal of DWPF decontaminated salt have been estimated by reviewing water level records from several water table wells in the vicinity. The highest grou...

R. W. Root

1980-01-01

13

Rhine and Meuse Floods of 1995—how predictable are water levels in The Netherlands?  

Microsoft Academic Search

Extreme amounts of precipitation in the drainage basins of the Rhine and Meuse caused peak flows in both rivers in January 1995. Critical water levels were exceeded, and by way of precaution more than 200 000 people were evacuated. During such floods, water level forecasts are important as base information for flood management. The forecasts for the Rhine and Meuse

BART PARMET

1997-01-01

14

Analysis and Prediction of Dissolved Oxygen Levels in Water downstream of Three Gorges Dam  

Microsoft Academic Search

The dissolved oxygen in the water below the Three Gorges Dam became supersaturated in the spill season after the reservoir has stored water since 2003. The change of dissolved oxygen concentration before and after the storing is compared and analyzed based on the measured water quality data of Miaohe Section and Huanglingmiao Section, which are the nearest sections upstream and

Z. Liu; J. Fu; Y. Chen

2008-01-01

15

Predicting Ground Water Flow  

NSDL National Science Digital Library

In this activity students learn how to draw ground water contours and understand how ground water flow may be predicted. As they complete this activity students will be able to draw a ground water contour map, have a basic understanding of how to predict the direction of ground water flow and understand the interrelated nature of ground water and surface water flow. They will also learn the difference between a gaining stream and a losing stream and why it is important to know the difference.

16

About Water Levels, Tides & Currents  

NSDL National Science Digital Library

The Oceanographic Products and Services Division (OPSD) of the National Oceanic and Atmospheric Administration (NOAA) "collects, analyzes and distributes historical and real-time observations and predictions of water levels, coastal currents and other meteorological and oceanographic data." This wonderful site explains the science behind the tides and changing water levels, gives historical background on tidal predictions and tidal machines (including several fascinating old photographs), and details the challenges of measuring water currents. The combination of engineering, history, and oceanography ensures that students and educators will learn much here. For access to tidal data, a tidal and current glossary, and an interactive tidal prediction page, users may follow links from the OPSD homepage.

2007-11-28

17

Predicting pesticide environmental risk in intensive agricultural areas. I: Screening level risk assessment of individual chemicals in surface waters.  

PubMed

A GIS-based procedure for assessing and mapping pesticide ecotoxicological risk for surface waters was applied to all active ingredients used in a catchment characterized by intensive agriculture. Chemical concentrations in riverwaterwere calculated for 54 chemicals in 25 drift and 21 runoff events that occurred during the growing season, from March to September. Screening level risk for the aquatic community was estimated using a risk index. The different role of drift and runoff processes, as well as the temporal trends of exposure and risk, were compared for the three classes of pesticides (herbicides, fungicides, and insecticides). High levels of risk are usually associated with runoff events for herbicides and to drift events for insecticides and fungicides. The described approach may serve as a powerful tool for a comparative evaluation of site-specific pesticide risk for surface water. However, for large-scale risk mapping, getting information on pesticide use with sufficient detail would be the major problem. PMID:19238989

Verro, Roberto; Finizio, Antonio; Otto, Stefan; Vighi, Marco

2009-01-15

18

Predicting Indoor Air Pollution Levels.  

National Technical Information Service (NTIS)

This paper describes methods of predicting concentration levels of indoor air pollution in a variety of residences by using residence air-infiltration rates, residence volumes, and source terms, and by making assumptions about occupant lifestyle and pollu...

G. B. Parker J. G. Droppo P. C. Owczarski

1982-01-01

19

Reasons and Predictions of The Caspian Sea Water Level Fluctuations: Impact of Climate Factors and Man's Activities.  

NASA Astrophysics Data System (ADS)

The Caspian Sea - the largest lake in the world - has no connection with the Ocean and is lower than its surface. Fluctuations of the Sea level are very significant: during the period of instrumental observations (since 1830) the level amplitude was 3.78 m with maximum of -25.22 m in 1882 and minimum of -29.00 m in 1978. These fluctuations lead to a great damage for the economy of five countries sharing its coast (Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan). Deep knowledge of hydrological and hydrodynamic Sea regime and scientifically justified forecasts of possible changes in its level, taking into account variability in climate and future climate change, are re- quired for undertaking urgent measures for protection of coastal territories. The inter- national research project CASSEAS, carried out in 1997-2000 within the framework of the INCO-COPERNICUS programme by the scientists of 5 countries: France, Rus- sia, Germany, Turkmenistan and UK, was devoted to these problems. Research made within the Project made it possible to get new precise data on all water balance com- ponents of the Caspian Sea for 1880-1996; moreover, all water balance components for 1940-1996 were computed independently. It was shown that the Sea level fluctua- tions depended on the water balance almost completely. Assessment of possible future runoff changes in the Caspian Sea basin was made using the mathematical model of runoff formation developed at the SHI. Several scenarios from a range of GCMs and on the basis of paleoclimatic reconstructions were used as the models of the future climate for the nearest 3 decades. Besides changes in climate characteristics, three variants were accepted for the future water use in the basins of rivers discharging to the Caspian Sea. All scenarios gave similar results for changes in annual river inflow to the Caspian Sea: its increase would be from 5% to 10% by 2030. The same scenarios, used to estimate changes in precipitation onto the Sea surface and evaporation from it, made it possible to expect visible evaporation increase by 5-10%. To make a prob- abilistic forecast of the Caspian Sea level before 2030 a dynamic stochastic model of the Caspian Sea long-term level fluctuations developed at the SHI was used. The main conclusions based on the modelling results are as follows: - Water level fall is most probable in the future. Mean Sea level mark may be within -27.2 ...-27.3 m (2005), -27.6 ...-28.0 m (2015), -28.4 ...-28.9 m (2030); - A probable Sea level deviation from its mean position at the confidence probability of 95% may be +/- 0.75 m by 2005, +/- 1 1.3 m by 2015 and +/- 1.6 m by 2030; - During the nearest decade the probability of exceedence of the Sea level above -26.0 m would be less than 1%, above -25.5 m less than 0.1% (once per 1000 years); in the next two decades the probability of this event would be even lower; - These conclusions should be considered for decision-making on a development and implementation of projects to protect the coastal zone of the Caspian Sea. 2

Erlich, M.; Shiklomanov, I.; Yezhov, A.; Georgievsky, V.; Shalygin, A.

20

Predicted water-level and water-quality effects of artificial recharge in the Upper Coachella Valley, California, using a finite-element digital model  

USGS Publications Warehouse

From 1936 to 1974, water levels declined more than 100 feet in the Palm Springs area and 60 feet in the Palm Desert area of the upper Coachella Valley, Calif. Water from the Colorado River Aqueduct is presently being recharged to the basin. The dissolved-solids concentration of native ground water in the recharge area is about 210 mg/liter and that of recharge water ranges from 600 to 750 mg/liter. A finite-element model indicates that without recharge the 1974 water levels in the Palm Springs area will decline 200 feet by the year 2000 because of pumpage. If the aquifer is recharged at a rate from about 7 ,500 acre-feet per year in 1973 increasing to 61,200 acre-feet per year in 1990 and thereafter, the water level in the Palm Springs area will decline about 20 feet below the 1974 level by 1991 and recover to the 1974 level by 2000. The solute-transport finite-element model of the recharge area indicates that the artificial recharge plume (bounded by the 300-mg/liter line) will move about 1.1 miles downgradient of the recharge ponds by 1981 and about 4.5 miles from the ponds by 2000. (Woodard-USGS)

Swain, Lindsay A.

1978-01-01

21

Probability prediction of the Caspian sea level with consideration of the development of water-consuming industries in its basin  

SciTech Connect

This article discusses the consequences for the Caspian Sea of the future economic and industrial development of the area and proposes a strategy for forecasting its continued existence from hydrological and meteorological standpoints as well as on the basis of projected water consumption by the industries moving into the area. Further strategies are put forth for resource management and conservation which are responsive to variations in the level of the sea and in the inflow from surrounding rivers and watersheds. Government policy toward development and utilization of the Caspian Sea over the past few years is also discussed.

Berezner, A.S.

1987-11-01

22

Great Lakes water levels  

Microsoft Academic Search

A new publication, Great Lakes Water Levels, 1860-1970, has been issued by the Lakes Survey Center of the National Oceanic and Atmospheric Administration. \\u000a\\u000aThe book contains tabular records of monthly and annual average water surface elevations for each of the more than 50 permanent gages in the Lake Survey network. There are also summaries of the average and extreme levels

Anonymous

1971-01-01

23

FLOOD EXTENT PREDICTION FROM LAKE HEIGHTS AND WATER LEVEL ESTIMATION FROM FLOOD EXTENTS USING RIVER GAUGES, ELEVATION MODELS AND ENVISAT DATA  

Microsoft Academic Search

Water levels and water extents are essential information in flood monitoring and forecasting. Two experimental and complementary ways were explored in order to estimate water level and water extent and forecast them: 1) The estimation of water level through combining water extents derived from earth observation data with elevation from a Digital Elevation Model; 2) The estimation of flood extents

ANDREOLI Rémi; YESOU Hervé; Bld Sébastien Brant

2007-01-01

24

NOAA: About Water Levels, Tides and Currents  

NSDL National Science Digital Library

A comprehensive lesson on what causes tides, current and past techniques for predicting tides, how and why water level is measured, and the challenges of measuring water currents. Site provides additional links to other NOAA tide resources.

25

Probabilistic Discovery of Motifs in Water Level  

Microsoft Academic Search

The discovery of water level time series motifs is of much importance to improve the water level predictions. These predictions thereby are useful to the shipping industry, people living in the coastal areas, and even for emergency evacuation in case of a hurricane. In this paper, symbolic aggregate approximation (SAX) is employed to index and reduce the dimension of the

Longzhuang Li; Sreekrishan Nallela

2009-01-01

26

Sentence-Level Attachment Prediction  

NASA Astrophysics Data System (ADS)

Attachment prediction is the task of automatically identifying email messages that should contain an attachment. This can be useful to tackle the problem of sending out emails but forgetting to include the relevant attachment (something that happens all too often). A common Information Retrieval (IR) approach in analyzing documents such as emails is to treat the entire document as a bag of words. Here we propose a finer-grained analysis to address the problem. We aim at identifying individual sentences within an email that refer to an attachment. If we detect any such sentence, we predict that the email should have an attachment. Using part of the Enron corpus for evaluation we find that our finer-grained approach outperforms previously reported document-level attachment prediction in similar evaluation settings.

Albakour, M.-Dyaa; Kruschwitz, Udo; Lucas, Simon

27

PREDICTING FUTURE WATER DEMAND  

EPA Science Inventory

Decentralization within metropolitan areas has been a major aspect of population movement in the United States over the past two decades. The trend has great significance for all urban service activities. In particular, it affects water supply planning in urban areas. Both number...

28

Water in protein structure prediction  

PubMed Central

Proteins have evolved to use water to help guide folding. A physically motivated, nonpairwise-additive model of water-mediated interactions added to a protein structure prediction Hamiltonian yields marked improvement in the quality of structure prediction for larger proteins. Free energy profile analysis suggests that long-range water-mediated potentials guide folding and smooth the underlying folding funnel. Analyzing simulation trajectories gives direct evidence that water-mediated interactions facilitate native-like packing of supersecondary structural elements. Long-range pairing of hydrophilic groups is an integral part of protein architecture. Specific water-mediated interactions are a universal feature of biomolecular recognition landscapes in both folding and binding.

Papoian, Garegin A.; Ulander, Johan; Eastwood, Michael P.; Luthey-Schulten, Zaida; Wolynes, Peter G.

2004-01-01

29

Radon levels can be predicted  

NASA Astrophysics Data System (ADS)

Scientists doing a yearlong study of radon levels in houses have identified several major factors that affect concentrations and have developed a method for predicting indoor radon levels before a house is built. Douglas Mose and George Mushrush (George Mason University, Fairfax, Va.) studied 1500 homes in northern Virginia and central Maryland near Washington, D.C.Radon is a radioactive decay product of uranium that occurs in many rock types. The gas can accumulate in buildings and pose a serious health hazard. Results from the Washington-area study show that ˜35% of the houses had average yearly radon concentrations above 4 pico-Curies per liter (pCi/L), the level at which the Environmental Protection Agency (EPA) suggests that a homeowner should take steps to reduce radon concentrations. At a level of 4-10 pCi/L an estimated 13-120 lung cancer deaths would be expected for every 1000 people exposed. Such a risk is comparable to having 200 chest X rays per year, according to EPA statistics.

Wainger, Lisa A.

30

Prediction level of noise by a helicopter  

NASA Astrophysics Data System (ADS)

This paper describes the prediction level of noise which is generated by a helicopter. The relation between noise levels and distance from the helicopter to an observing point is measured. From these measured results, acoustic power level generated by the helicopter is calculated. Noise levels can be estimated by measuring the distance from the helicopter's flight path. Prediction of the noise levels is in good agreement with measured noise levels.

Shibayama, Hideo; Takayama, Takashi; Nakamura, Shin'iti

31

Predicting semantic priming at the item level  

Microsoft Academic Search

The current study explores a set of variables that have the potential to predict semantic priming effects for 300 prime–target associates at the item level. Young and older adults performed either lexical decision (LDT) or naming tasks. A multiple regression procedure was used to predict priming based upon prime characteristics, target characteristics, and prime–target semantic similarity. Results indicate that semantic

Keith A. Hutchison; David A. Balota; Michael J. Cortese; Jason M. Watson

2008-01-01

32

Bathing water signage and predictive water quality models in Scotland  

Microsoft Academic Search

The Scottish Environment Protection Agency (SEPA) has developed, and runs, real-time bathing water quality predictions at ten sites throughout Scotland since 2004. Daily bathing water quality predictions are posted on electronic variable message signs at 10 beach locations networked to a central communication centre and updates are simultaneously made on the SEPA website, phone and text message service.Antecedent rainfall and

Calum D. McPhail; Ruth T. Stidson

2009-01-01

33

Ground-water levels in Wyoming, 1975  

USGS Publications Warehouse

Ground-water levels are measured periodically in a network of about 260 observation wells in Wyoming to record changes in ground-water storage. The areas of water-level observation are mostly where ground water is used in large quantities for irrigation or municipal purposes. This report contains maps showing location of observation wells and water-level changes from 1975 to 1976. Well history, highest and lowest water levels , and hydrographs for most wells also are included. (Woodard-USGS)

Ballance, W. C.; Freudenthal, Pamela B.

1976-01-01

34

Predicting Internal Roughness in Water Mains.  

National Technical Information Service (NTIS)

A method is presented for predicting the Hazen-Williams C-factor for unlined metal water mains as a function of pipe age. The method has two steps: (a) finding the growth/rate of internal roughness, alpha, for the water main using either historical C-fact...

T. M. Walski W. W. Sharp F. D. Shields

1988-01-01

35

Satellite Water Impurity Marker (SWIM) for predicting seasonal cholera outbreaks  

NASA Astrophysics Data System (ADS)

Prediction of outbreaks of cholera, a deadly water related disease, remains elusive. Since coastal brackish water provides a natural ecological niche for cholera bacteria and because a powerful evidence of new biotypes is emerging, it is highly unlikely that cholera will be fully eradicated. Therefore, it is necessary to develop cholera prediction model with several months' of lead time. Satellite based estimates of chlorophyll, a surrogate for phytoplankton abundance, has been associated with proliferation of cholera bacteria. However, survival of cholera bacteria in a variety of coastal ecological environment put constraints on predictive abilities of chlorophyll algorithm since it only measures greenness in coastal waters. Here, we propose a new remote sensing reflectance based statistical index: Satellite Water Impurity Marker, or SWIM. This statistical index estimates impurity levels in the coastal waters and is based on the variability observed in the difference between the blue (412nm) and green (555nm) wavelengths in coastal waters. The developed index is bounded between clear and impure water and shows the ability to predict cholera outbreaks in the Bengal Delta with a predicted r2 of 78% with two months lead time. We anticipate that a predictive system based on SWIM will provide essential lead time allowing effective intervention and mitigation strategies to be developed for other cholera endemic regions of the world.

Jutla, A. S.; Akanda, A. S.; Islam, S.

2011-12-01

36

Prediction of surface pressures during water impact  

Microsoft Academic Search

A potential flow model was developed to predict pressures and loads during the oblique water impact of axisymmetric bodies. The free surface is replaced by an effective planar surface which is positioned using experimental information. At each depth, the flow field solution is determined using a distribution of sources on the model surface. Pressures, calculated by Bernoulli's equation, are integrated

A. B. Wardlaw Jr.; P. M. Aronson

1977-01-01

37

Ground-water levels in Wyoming, 1976  

USGS Publications Warehouse

Ground-water levels are measured periodically in a network of about 280 observation wells in Wyoming to record changes in ground-water storage. The areas of water-level observation are mostly where ground water is used in large quantities for irrigation or municipal purposes. This report contains maps showing location of observation wells and water-level changes from 1976 to 1977. Well history, highest and lowest water levels , and hydrographs for most wells also are included. The program of groundwater observation is conducted by the U.S. Geological Survey in cooperation with the Wyoming State Engineer and the city of Cheyenne. (Woodard-USGS)

Ballance, W. C.; Freudenthal, Pamela B.

1977-01-01

38

Installing Water-Level Monitoring Gage  

USGS Multimedia Gallery

Installing a water-level monitoring gage, Coosawattee River, Georgia. Two USGS workers installing a "stilling well"s, which is a major component of most systems used to monitor stream stage (gage height). The pipe is placed vertically into the stream and the level of the water in the pipe is co...

2008-12-04

39

Two-level adaptive training branch prediction  

Microsoft Academic Search

High-performance microarchitectures use, among other structures, deep pipelines to help speed up exe- cution. The importance of a good branch predictor to the effectiveness of a deep pipeline in the presence of condi- tional branches is well-known. In fact, the literature contains proposals for a number of branch prediction schemes. Some are static in that they use opcode information and

Tse-Yu Yeh; Yale N. Patt

1991-01-01

40

Predicting Demonstrations' Violence Level Using Qualitative Reasoning  

NASA Astrophysics Data System (ADS)

In this paper we describe a method for modeling social behavior of large groups, and apply it to the problem of predicting potential violence during demonstrations. We use qualitative reasoning techniques which to our knowledge have never been applied to modeling crowd behaviors, nor in particular to demonstrations. Such modeling may not only contribute to the police decision making process, but can also provide a great opportunity to test existing theories in social science. We incrementally present and compare three qualitative models, based on social science theories. The results show that while two of these models fail to predict the outcomes of real-world events reported and analyzed in the literature, one model is successful. We believe that this demonstrates the efficacy of qualitative reasoning in the development and testing of social sciences theories.

Fridman, Natalie; Zilberstein, Tomer; Kaminka, Gal A.

41

Stabilized water levels and Typha invasiveness  

Microsoft Academic Search

Because Typha × glauca often dominates wetlands where humans have stabilized the natural hydrologic regime, we 1) compared its expansion rates where\\u000a water levels were stabilized vs. fluctuating and 2) explored the potential for stabilized water levels to allow plants to\\u000a accumulate more phosphorus (P) and increase growth. In three Wisconsin marshes, the area dominated by Typha expanded linearly over

Aaron M. Boers; Joy B. Zedler

2008-01-01

42

Defect level prediction for newly designed Printed Circuit Board Assemblies  

Microsoft Academic Search

In this paper a new defect level prediction tool is presented, which is intended for newly designed printed circuit board assemblies, especially for the PCBAs (printed circuit board assembly) determined for automotive industry. The tool is programmed in Visual Basic for Application (VBA) and can be operated in MS Excel environment. On the one hand, the defect level prediction tool

R. Soukup

2009-01-01

43

Forcast of Poyang lake's water level by Wavelet-ANFIS model  

Microsoft Academic Search

Poyang Lake is China's largest freshwater lake. It has good regulation role to Yangtze River. After the running of Three Georges Project, it influences the water level of Poyang Lake a lot. This paper predicts Poyang Lake's water level, it is the basic of influence research. Once there were many predicting methods, such as ANN, etc. But these methods are

Rijun Zhang; Zengchuan Dong; Huifang Guo

2009-01-01

44

Model predictive control of water transportation networks  

Microsoft Academic Search

In this paper water distribution systems and sewer systems are considered. Both can be seen as complementary networks: water distribution systems supply the commodity to consumers while sewer systems drain the wastewater which is produced by domestic usage and industrial facilities. In the water distribution case an application of a distributed control scheme for management of urban water supply networks

Catherin Zamora; Juan Manuel Giraldo; Sylvain Leirens

2010-01-01

45

Predictions of the properties of water from first principles  

Microsoft Academic Search

A force field for water has been developed entirely from first principles, without any fitting to experimental data. It contains both pairwise and many-body interactions. This force field predicts the properties of the water dimer and of liquid water in excellent agreement with experiments, a previously elusive objective. Precise knowledge of the intermolecular interactions in water will facilitate a better

R. Bukowski; K. Szalewicz; G. C. Groenenboom; A. van der Avoird

2007-01-01

46

Neural networks and M5 model trees in modelling water level-discharge relationship  

Microsoft Academic Search

Reliable estimation of discharge in a river is the crucial component of efficient flood management and surface water planning. Hydrologists use historical data to establish a relationship between water level and discharge, which is known as a rating curve. Once a relationship is established it can be used for predicting discharge from future measurements of water level only. Successful applications

Biswanath Bhattacharya; Dimitri P. Solomatine

2005-01-01

47

Hydrostatic Water Level Systems At Homestake DUSEL  

Microsoft Academic Search

Two arrays of Fermilab-style hydrostatic water level sensors have been installed in the former Homestake gold mine in Lead, SD, the site of the new Deep Underground Science and Engineering Laboratory (DUSEL). Sensors were constructed at Fermilab from 8.5 cm diameter PVC pipe (housing) that was sealed on the ends and fit with a proximity sensor. The instrument have a

L. D. Stetler; J. T. Volk

2009-01-01

48

Predicting Students' Homework Environment Management at the Secondary School Level  

ERIC Educational Resources Information Center

The present study examined empirical models of variables posited to predict students' homework environment management at the secondary school level. The participants were 866 8th graders from 61 classes and 745 11th graders from 46 classes. Most of the variance in homework environment management occurred at the student level, with classmates'…

Xu, Jianzhong

2012-01-01

49

Predicting students’ homework environment management at the secondary school level  

Microsoft Academic Search

The present study examined empirical models of variables posited to predict students’ homework environment management at the secondary school level. The participants were 866 8th graders from 61 classes and 745 11th graders from 46 classes. Most of the variance in homework environment management occurred at the student level, with classmates’ shared homework interest as the only significant predictor at

Jianzhong Xu

2011-01-01

50

Predicting students’ homework environment management at the secondary school level  

Microsoft Academic Search

The present study examined empirical models of variables posited to predict students’ homework environment management at the secondary school level. The participants were 866 8th graders from 61 classes and 745 11th graders from 46 classes. Most of the variance in homework environment management occurred at the student level, with classmates’ shared homework interest as the only significant predictor at

Jianzhong Xu

2012-01-01

51

Predicting Students' Homework Environment Management at the Secondary School Level  

ERIC Educational Resources Information Center

|The present study examined empirical models of variables posited to predict students' homework environment management at the secondary school level. The participants were 866 8th graders from 61 classes and 745 11th graders from 46 classes. Most of the variance in homework environment management occurred at the student level, with classmates'…

Xu, Jianzhong

2012-01-01

52

Predicting and understanding home garden water use  

Microsoft Academic Search

There is now substantial literature describing the importance of home gardens for a variety of quality of life variables such as avoidance of stress, recreation and personal and social identity. From a water resource management perspective it is reasonable to hypothesise that those households that gain the most personal benefits from their gardens will use more water. Consideration of the

Geoffrey J. Syme; Quanxi Shao; Murni Po; Eddy Campbell

2004-01-01

53

Water Management, Rainwater Harvesting and Predictive Variables in Rural Households  

Microsoft Academic Search

Water management in rural domestic households plays an important role in reducing water-related health risks. This study was\\u000a conducted to examine the relationships between the dependent variable (rural domestic rainwater management) and the independent\\u000a predictive variables (personal characteristics, tank size, years of water harvest, rainwater harvesting associations, usage\\u000a instructions including water borne health risk, and tank operation and maintenance) in

David Baguma; Willibald Loiskandl; Helmut Jung

2010-01-01

54

Predictions of the properties of water from first principles.  

PubMed

A force field for water has been developed entirely from first principles, without any fitting to experimental data. It contains both pairwise and many-body interactions. This force field predicts the properties of the water dimer and of liquid water in excellent agreement with experiments, a previously elusive objective. Precise knowledge of the intermolecular interactions in water will facilitate a better understanding of this ubiquitous substance. PMID:17332406

Bukowski, Robert; Szalewicz, Krzysztof; Groenenboom, Gerrit C; van der Avoird, Ad

2007-03-01

55

AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES  

SciTech Connect

Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

2011-01-14

56

Observed Currents and Water Levels in Hamilton Harbour  

Microsoft Academic Search

Measurements of currents, water levels, meteorological inputs and temperatures were made in Hamilton Harbour during 1991. This paper describes the field program and derives features of currents and water level variations. Although the water level measurements clearly showed the fundamental seiche of the harbor itself (period 23 minutes, amplitude 1 mm), the water level in the harbor closely tracks the

Jian Wu; Ioannis K. Tsanis; Fausto Chiocchio

1996-01-01

57

PREDICTING WATER QUALITY IN DISTRIBUTION SYSTEMS  

EPA Science Inventory

The quality of a public water supply although acceptable when it leaves the treatment plant, may deteriorate before it reaches the user. Deterioration may be caused by either chemical or biological transformations or by a loss of system integrity. There have been a growing number...

58

Water-level fluctuations in North American prairie wetlands  

Microsoft Academic Search

Oscillatory water-level fluctuations are reversible changes in water levels around a long-term mean. Long-term water-level studies in wetlands in the prairie pothole region of North America and proxy data (e.g., tree rings) for water levels in this region indicate that oscillatory water-level fluctuations have occurred for thousands of years. Because there has been no standard set of terms to describe

Arnold G. van der. Valk

2005-01-01

59

Hormone Levels May Help Predict Breast Cancer Risk, Study Finds  

MedlinePLUS

... please enable JavaScript. Hormone Levels May Help Predict Breast Cancer Risk, Study Finds Higher blood concentrations of testosterone, ... Mozes Wednesday, October 30, 2013 Related MedlinePlus Pages Breast Cancer Hormones Laboratory Tests TUESDAY, Oct. 29 (HealthDay News) -- ...

60

Alternative implementations of two-level adaptive branch prediction  

Microsoft Academic Search

As the issue rate and depth of pipelining of high performance Superscalar processors increase, the importance of an excellent branch predictor becomes more vital to delivering the potential performance of a wide-issue, deep pipelined microarchitecture. We propose a new dynamic branch predictor (Two-Level Adaptive Branch Prediction) that achieves substantially higher accuracy than any other scheme reported in the literature. The

Tse-Yu Yeh; Yale N. Patt

1992-01-01

61

Water Level Decline Promotes Typha X glauca Establishment and Vegetation Change in Great Lakes Coastal Wetlands  

Microsoft Academic Search

Climate change is predicted to reduce Laurentian Great Lakes water levels, altering coastal wetland ecosystems and potentially\\u000a stimulating invasive macrophytes, like Typha X glauca. Recent prolonged low water levels, which climaxed in 2007, created conditions comparable to those predicted by climate change\\u000a science. In 2008, we examined ecosystem and plant community properties in 14 intact northern Great Lakes coastal wetlands

Shane C. Lishawa; Dennis A. Albert; Nancy C. Tuchman

2010-01-01

62

Water Habitat Study: Prediction Makes It More Meaningful.  

ERIC Educational Resources Information Center

Suggests a teaching strategy for water habitat studies to help students make a meaningful connection between physiochemical data (dissolved oxygen content, pH, and water temperature) and biological specimens they collect. Involves constructing a poster and using it to make predictions. Provides sample poster. (DC)

Glasgow, Dennis R.

1982-01-01

63

Water Habitat Study: Prediction Makes It More Meaningful.  

ERIC Educational Resources Information Center

|Suggests a teaching strategy for water habitat studies to help students make a meaningful connection between physiochemical data (dissolved oxygen content, pH, and water temperature) and biological specimens they collect. Involves constructing a poster and using it to make predictions. Provides sample poster. (DC)|

Glasgow, Dennis R.

1982-01-01

64

Applying Knowledge Discovery to Predict Water-Supply Consumption  

Microsoft Academic Search

ations in a municipal water-distribution sys-tem can reduce electricity costs and realize other economic benefits. However, optimal control requires an ability to precisely predict short-term water demand so that minimum-cost pumping schedules can be prepared. One of the objectives of our project to develop an intelligent system for monitoring and con-trolling municipal water-supply systems is to ensure optimal control and

An Aijun; Christine W. Chan; Ning Shan; Nick Cercone; Wojciech Ziarko

1997-01-01

65

Prediction of water content of sour and acid gases  

Microsoft Academic Search

Estimating the feasibility of acid gas geological disposal requires the knowledge of the water content of the gas phase at moderate pressures and temperatures (typically below 50MPa, below 380K) and up to 6mol NaCl. In this paper, a non-iterative model is developed to predict the water content of sour and acid gases at equilibrium with pure water and brine. This

Mohsen Zirrahi; Reza Azin; Hassan Hassanzadeh; Mahmood Moshfeghian

2010-01-01

66

County-Level Crop Yield Prediction Using Remote Sensing Data  

NASA Astrophysics Data System (ADS)

Early estimates of crop yield, particularly at a fine scale, can inform precision agriculture efforts. The USDA National Agricultural Statistics Service (NASS) currently provides estimates of yield on a monthly basis for each state. These estimates are based on phone interviews with farmers and in-situ examination of randomly selected plots. We seek to provide predictions at a much higher spatial resolution, on a more frequent basis, using remote sensing observations. We use publicly available data from the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on the Aqua and Terra spacecraft. These observations have a spatial resolution of 250 m and consist of two spectral bands (red and infra-red) with a repeat period of 8 days. As part of the HARVIST (Heterogeneous Agricultural Research Via Interactive, Scalable Technology) project, we have created statistical crop yield models using historical MODIS data combined with the per-county yield reported by the USDA at the end of the growing season. In our approach, we analyze 100 randomly selected historical pixels from each county to generate a yield prediction for the county as a whole. We construct a time series for each pixel that consists of its NDVI (Normalized Difference Vegetation Index) value observed during each 8-day time period to date. We then cluster all pixels together to identify groups of distinct elements (different crops, bodies of water, urban areas, desert, etc.) and create a regression model for each one. For each crop of interest, the model that best predicts that crop's historical yield is selected. These models can then be applied to data from subsequent years to generate predictions for the future. We applied this approach to data from California and Kansas for corn and wheat. We found that, in general, the yield prediction error decreased as the harvest time approached. In California, distinctly different models were selected to predict corn and wheat, permitting specialization for each crop type. The best models from 2001 predicted yield for 2002 with a 10% (corn) and 23% (wheat) relative error three months before harvest. In Kansas, the 2001 models for corn and wheat were not well distinguished, providing good predictions for wheat (19% error three months before harvest) but poor predictions for corn (55% error three months before harvest). In post-analysis, we found that the 2001 pixel NDVI time series for Kansas are much more homogeneous than those for California, making it difficult to select crop-specific models. We are currently working on incorporating historical data from additional years, which will provide more diversity and potentially better predictions. We are also in the process of applying this technique to additional crops.

Wagstaff, K. L.; Roper, A.; Lane, T.

2007-12-01

67

Robust predictive modelling of water pollution using biomarker data.  

PubMed

This paper describes the methodology of building a predictive model for the purpose of marine pollution monitoring, based on low quality biomarker data. A step-by-step, systematic data analysis approach is presented, resulting in design of a purely data-driven model, able to accurately discriminate between various coastal water pollution levels. The environmental scientists often try to apply various machine learning techniques to their data without much success, mostly because of the lack of experience with different methods and required 'under the hood' knowledge. Thus this paper is a result of a collaboration between the machine learning and environmental science communities, presenting a predictive model development workflow, as well as discussing and addressing potential pitfalls and difficulties. The novelty of the modelling approach presented lays in successful application of machine learning techniques to high dimensional, incomplete biomarker data, which to our knowledge has not been done before and is the result of close collaboration between machine learning and environmental science communities. PMID:20362318

Budka, Marcin; Gabrys, Bogdan; Ravagnan, Elisa

2010-03-16

68

Probable high ground-water levels on Cape Cod, Massachusetts  

USGS Publications Warehouse

Water-level records from 146 short-term (1 year) observation wells and 13 long-term (16-28 years) observation wells were used to estimate the probable high ground-water level that could occur at any site on Cape Cod. The estimation was based on correlation of a single water-level measurement from a test site with water-level records of the nine index wells. Maps showing areas of Cape Cod represented by the nine index wells and showing five ranges of water-level fluctuation are used in conjunction with tables of water-level adjustments to make the estimates. (USGS)

Frimpter, Michael H.

1980-01-01

69

Seasonal Predictability of Water Scarcity at the Global Scale  

NASA Astrophysics Data System (ADS)

Timely indication of water scarcity is most important for early mitigation of serious water and food shortages across the globe. Within the EU FP7 GLOWASIS project a pre-validated GMES Global Service for Water Scarcity Information has been set up and tested. The service uses the global hydrological model PCR-GLOBWB to compute water fluxes and establishes monthly water scarcity by combining the outputs from PCR-GLOBWB with a number of water demands. The service has been set up in the forecast shell Delft-FEWS. In this contribution, we evaluate the skill of the system across the globe in terms of forecasting a number of drought and water scarcity related indicators such as the water scarcity index, river discharge, soil moisture content and actual evaporation. First, we test how much skill is gained from memory by comparing skill from an Ensermble Streamflow Prediction (ESP) and reverse ESP (revESP) experiment using ERAInterim precipitation (GPCP corrected), temperature and Penman Monteith potential evaporation. From these experiments, critical lead times are derived for water scarcity, discharge and other hydrologic variables indicating the relative importance of initial condition versus meteorological forcing (at 0.5 degree resolution). Subsequently, from a seasonal hydrological hindcast of 30 years (1981-2010) the added value of ECMWF seasonal forecasts (with and without bias correction) over climatological forecasts (e.g. ESP) is evaluated by looking qualitatively at the 'actual skill' of the water scarcity forecasts for individual water scarcity/drought events over the globe. The first analyses show that predictability of water scarcity is highly variable across the globe (per season and location). In some areas water scarcity is predictable at least up to three month lead time.

Weerts, Albrecht; Winsemius, Hessel; Dutra, Emanuel; Beckers, Joost; Brolsma, Reinder; van Beek, Rens; Pappenberger, Florian; Westerhoff, Rogier; Bierkens, Marc

2013-04-01

70

Accurate Predictive Interconnect Modeling for System-Level Design  

Microsoft Academic Search

We propose new accurate predictive models for the delay, power, and area of buffered interconnects to enable a more effective system-level design exploration with existing and future nanometer technology processes. We show that our models are significantly more accurate than previous models—essentially matching sign-off analyses. We integrate our models in the COSI-OCC communication synthesis infra- structure and show how they

Luca P. Carloni; Andrew B. Kahng; Sudhakar Muddu; Alessandro Pinto; Kambiz Samadi; Puneet Sharma

2010-01-01

71

Serum Myeloperoxidase Levels Independently Predict Endothelial Dysfunction in Humans  

Microsoft Academic Search

Background—In vitro and animal studies demonstrate that myeloperoxidase catalytically consumes nitric oxide as a substrate, limiting its bioavailability and function. We therefore hypothesized that circulating levels of myeloperoxidase would predict risk of endothelial dysfunction in human subjects. Methods and Results—Serum myeloperoxidase was measured by enzyme-linked immunoassay, and brachial artery flow-mediated dilation and nitroglycerin-mediated dilation were determined by ultrasound in a

Joseph A. Vita; Marie-Luise Brennan; Noyan Gokce; Shirley A. Mann; Marlene Goormastic; Mehdi H. Shishehbor; Marc S. Penn; John F. Keaney; Stanley L. Hazen

2011-01-01

72

Methodology for predicting cooling water effects on fish  

Microsoft Academic Search

The mathematical model presented here predicts the long-term effects of once-through cooling water systems on local fish populations. The fish life cycle model simulates different life stages of fish by using appropriate expressions representing growth and mortality rates. The heart of the developed modeling approach is the prediction of plant-caused reduction in total fish population by estimating recruitment to adult

C. Cakiroglu; Cos?kun Yurteri

1998-01-01

73

Serum Myeloperoxidase Levels Independently Predict Endothelial Dysfunction in Humans  

PubMed Central

Background In vitro and animal studies demonstrate that myeloperoxidase catalytically consumes nitric oxide as a substrate, limiting its bioavailability and function. We therefore hypothesized that circulating levels of myeloperoxidase would predict risk of endothelial dysfunction in human subjects. Methods and Results Serum myeloperoxidase was measured by enzyme-linked immunoassay, and brachial artery flow–mediated dilation and nitroglycerin-mediated dilation were determined by ultrasound in a hospital-based population of 298 subjects participating in an ongoing study of the clinical correlates of endothelial dysfunction (age, 51±16; 61% men, 51% with cardiovascular disease). A strong inverse relation between brachial artery flow–mediated dilation and increasing quartile of serum myeloperoxidase level was observed (11.0±6.0%, 9.4±5.3%, 8.6±5.8%, and 6.4±4.5% for quartiles 1 through 4, respectively; P<0.001 for trend). Using the median as a cut point to define endothelial dysfunction, increasing quartile of myeloperoxidase predicted endothelial dysfunction after adjustment for classic cardiovascular disease risk factors, C-reactive protein levels, prevalence of cardiovascular disease, and ongoing treatment with cardiovascular medications (OR, 6.4; 95% CI, 2.6 to 16; P=0.001 for highest versus lowest quartile). Conclusions Serum myeloperoxidase levels serve as a strong and independent predictor of endothelial dysfunction in human subjects. Myeloperoxidase-mediated endothelial dysfunction may be an important mechanistic link between oxidation, inflammation, and cardiovascular disease.

Vita, Joseph A.; Brennan, Marie-Luise; Gokce, Noyan; Mann, Shirley A.; Goormastic, Marlene; Shishehbor, Mehdi H.; Penn, Marc S.; Keaney, John F.; Hazen, Stanley L.

2009-01-01

74

County Level Assessment of Impaired Waters and Gastrointestinal Infections  

EPA Science Inventory

Water quality data are measured at a watershed level and health data are organized at different levels of aggregation therefore, assessing the population-level impact of water quality on health can be difficult. To address this discrepancy and enable the consideration of water ...

75

Secular Changes in Great Lakes Water Level Seasonal Cycles  

Microsoft Academic Search

The three primary scales of Great Lakes water level fluctuations are interannual, seasonal, and episodic. Of these three, the seasonal water level fluctuations have received relatively little attention. The Great Lakes water levels have a well defined seasonal cycle driven primarily by snowmelt in the spring and summer and lake evaporation in the fall and winter. The present average seasonal

Frank H. Quinn

2002-01-01

76

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea  

Microsoft Academic Search

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion

W. S. Chung; M. J. Yu; H. D. Lee

77

Rising ground-water level in downtown Louisville, Kentucky, 1972-1977  

USGS Publications Warehouse

Ground-water levels in the alluvial aquifer in Louisville, Jefferson County, Kentucky, are rising at a rate which could cause wet basements and possible structural damage to buildings in the downtown area by 1982. The predicted water level for 1982 is based on the nearly linear increase which has been observed from 1972 to 1977, during which period a rise of as much as 32 feet was recorded in water-level observation wells. Foremost among the possible causes of the rise is a decrease in withdrawal of ground water. (Woodard-USGS)

Kernodle, J. M.; Whitesides, D. V.

1977-01-01

78

Safety handling characteristics of high-level tritiated water  

Microsoft Academic Search

In a fusion reactor, high-level tritiated water of more than one PBq\\/m3 will be generated and stored in various areas. The high-level tritiated water decomposes by itself and generates mainly hydrogen, becoming tritiated hydrogen peroxide water. In order to summarize safety requirements for long-term storage of high-level tritiated water, the characteristics, such as effective G-values of hydrogen and hydrogen peroxide,

T. Hayashi; T. Itoh; K. Kobayashi; K. Isobe; M. Nishi

2006-01-01

79

A predictive controller for a heaving buoy producing potable water  

Microsoft Academic Search

A model predictive controller for a wave-powered desalination unit is presented. The desalination unit is composed of a reverse osmosis membrane, and the water is pumped at high pressure through the membrane by a wave energy converter. The wave energy converter is a heaving buoy type connected to an hydraulic circuit that converts the oscillating motion of the buoy into

Giorgio Bacelli; Jean-Christophe Gilloteaux; John Ringwood

2009-01-01

80

Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters.  

PubMed

Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and water temperature, pH, oxidation-reduction potential (ORP), turbidity, and conductivity were measured. Weather data were obtained from nearby weather stations. Aerobic plate counts and most probable numbers (MPN) for Salmonella, E. coli, and coliforms were performed. Weak linear relationships existed between biological indicators (E. coli/coliforms) and Salmonella levels (R(2) < 0.1) and between physicochemical indicators and Salmonella levels (R(2) < 0.1). The average rainfall (previous day, week, and month) before sampling did not correlate well with bacterial levels. Logistic regression analysis showed that E. coli concentration can predict the probability of enumerating selected Salmonella levels. The lack of good correlations between biological indicators and Salmonella levels and between physicochemical indicators and Salmonella levels shows that the relationship between pathogens and indicators is complex. However, Escherichia coli provides a reasonable way to predict Salmonella levels in Central Florida surface water through logistic regression. PMID:23624476

McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D; Schaffner, Donald W; Danyluk, Michelle D

2013-04-26

81

SCREENING MODELS TO PREDICT PROBABILITY OF CONTAMINATION BY PATHOGENIC VIRUSES TO DRINKING WATER AQUIFERS  

EPA Science Inventory

The purpose of this research is to develop simple, screening level models to predict the overall ability of ground-water systems to attenuate viable viruses introduced to them. Compartmental modeling approaches are used because of their simplicity. Stakeholders and decision maker...

82

Integrating Non-Tidal Sea Level data from altimetry and tide gauges for coastal sea level prediction  

NASA Astrophysics Data System (ADS)

The main objective of this paper is to integrate Non-Tidal Sea Level (NSL) from the joint TOPEX, Jason-1 and Jason-2 satellite altimetry with tide gauge data at the west and north coast of the United Kingdom for coastal sea level prediction. The temporal correlation coefficient between altimetric NSLs and tide gauge data reaches a maximum higher than 90% for each gauge. The results show that the multivariate regression approach can efficiently integrate the two types of data in the coastal waters of the area. The Multivariate Regression Model is established by integrating the along-track NSL from the joint TOPEX/Jason-1/Jason-2 altimeters with that from eleven tide gauges. The model results give a maximum hindcast skill of 0.95, which means maximum 95% of NSL variance can be explained by the model. The minimum Root Mean Square Error (RMSe) between altimetric observations and model predictions is 4.99 cm in the area. The validation of the model using Envisat satellite altimetric data gives a maximum temporal correlation coefficient of 0.96 and a minimum RMSe of 4.39 cm between altimetric observations and model predictions, respectively. The model is furthermore used to predict high frequency NSL variation (i.e., every 15 min) during a storm surge event at an independent tide gauge station at the Northeast of the UK (Aberdeen).

Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

2012-10-01

83

Hepcidin level predicts hemoglobin concentration in individuals undergoing repeated phlebotomy.  

PubMed

Dietary iron absorption is regulated by hepcidin, an iron regulatory protein produced by the liver. Hepcidin production is regulated by iron stores, erythropoiesis and inflammation, but its physiology when repeated blood loss occurs has not been characterized. Hepcidin was assayed in plasma samples obtained from 114 first-time/reactivated (no blood donations in preceding 2 years) female donors and 34 frequent (?3 red blood cell donations in preceding 12 months) male donors as they were phlebotomized ?4 times over 18-24 months. Hepcidin levels were compared to ferritin and hemoglobin levels using multivariable repeated measures regression models. Hepcidin, ferritin and hemoglobin levels declined with increasing frequency of donation in the first-time/reactivated females. Hepcidin and ferritin levels correlated well with each other (Spearman's correlation of 0.74), but on average hepcidin varied more between donations for a given donor relative to ferritin. In a multivariable repeated measures regression model the predicted inter-donation decline in hemoglobin varied as a function of hepcidin and ferritin; hemoglobin was 0.51 g/dL lower for subjects with low (>45.7 ng/mL) or decreasing hepcidin and low ferritin (>26 ng/mL), and was essentially zero for other subjects including those with high (>45.7 ng/mL) or increasing hepcidin and low ferritin (>26 ng/mL) levels (P<0.001). In conclusion, hepcidin levels change rapidly in response to dietary iron needed for erythropoiesis. The dynamic regulation of hepcidin in the presence of a low levels of ferritin suggests that plasma hepcidin concentration may provide clinically useful information about an individual's iron status (and hence capacity to tolerate repeated blood donations) beyond that of ferritin alone. Clinicaltrials.gov identifier: NCT00097006. PMID:23445875

Mast, Alan E; Schlumpf, Karen S; Wright, David J; Johnson, Bryce; Glynn, Simone A; Busch, Michael P; Olbina, Gordana; Westerman, Mark; Nemeth, Elizabeta; Ganz, Tomas

2013-02-26

84

7 CFR 610.12 - Equations for predicting soil loss due to water erosion.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Equations for predicting soil loss due to water erosion. 610.12...CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a)...

2010-01-01

85

7 CFR 610.12 - Equations for predicting soil loss due to water erosion.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Equations for predicting soil loss due to water erosion. 610.12...CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a)...

2013-01-01

86

7 CFR 610.12 - Equations for predicting soil loss due to water erosion.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Equations for predicting soil loss due to water erosion. 610.12...CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a)...

2009-01-01

87

High levels of cellular proliferation predict pseudoprogression in glioblastoma patients  

PubMed Central

Radiochemotherapy (RT) with concomitant followed by monthly temozolomide (TMZ) chemotherapy is the gold standard for the treatment of glioblastoma (GBM) patients. GBM patients can experience transient radiological deterioration after concurrent RT/TMZ that stabilizes or even resolves after additional cycles of adjuvant TMZ, a phenomenon defined as radiological pseudoprogression. The aim of this retrospective study was to identify a reliable marker associated with pseudoprogression processes. Patients with histologically proven newly diagnosed GBM were identified from a retrospective database between 2005 and 2009. Predictive factors for pseudoprogression were analyzed from clinical, radiological and biological data. Of the 130 analyzed patients, 63 underwent RT/TMZ treatment followed by cycles of TMZ and were evaluated for radiological responses every two months by magnetic resonance imaging. Early progression was confirmed in 52% (33/63) of the patients, and, within this group, 21% (7/33) displayed evidence of pseudo-progression. The predictive factors were evidenced in terms of clinical or radiological findings. In GBM patients, the level of cellular proliferation (Ki67 indices) emerged as a statistically significant prognostic marker for distinguishing pseudoprogression from actual progression. Our observation, suggesting that GBM associated with a high level of cellular proliferation may differentiate tumor progression from pseudoprogression, warrants further investigation in a large multi-center prospective study.

POULEAU, HENRI-BENJAMIN; SADEGHI, NILOUFAR; BALERIAUX, DANIELLE; MELOT, CHRISTIAN; DE WITTE, OLIVIER; LEFRANC, FLORENCE

2012-01-01

88

High levels of cellular proliferation predict pseudoprogression in glioblastoma patients.  

PubMed

Radiochemotherapy (RT) with concomitant followed by monthly temozolomide (TMZ) chemotherapy is the gold standard for the treatment of glioblastoma (GBM) patients. GBM patients can experience transient radiological deterioration after concurrent RT/TMZ that stabilizes or even resolves after additional cycles of adjuvant TMZ, a phenomenon defined as radiological pseudoprogression. The aim of this retrospective study was to identify a reliable marker associated with pseudoprogression processes. Patients with histologically proven newly diagnosed GBM were identified from a retrospective database between 2005 and 2009. Predictive factors for pseudoprogression were analyzed from clinical, radiological and biological data. Of the 130 analyzed patients, 63 underwent RT/TMZ treatment followed by cycles of TMZ and were evaluated for radiological responses every two months by magnetic resonance imaging. Early progression was confirmed in 52% (33/63) of the patients, and, within this group, 21% (7/33) displayed evidence of pseudo-progression. The predictive factors were evidenced in terms of clinical or radiological findings. In GBM patients, the level of cellular proliferation (Ki67 indices) emerged as a statistically significant prognostic marker for distinguishing pseudoprogression from actual progression. Our observation, suggesting that GBM associated with a high level of cellular proliferation may differentiate tumor progression from pseudoprogression, warrants further investigation in a large multi-center prospective study. PMID:22086066

Pouleau, Henri-Benjamin; Sadeghi, Niloufar; Balériaux, Danielle; Mélot, Christian; De Witte, Olivier; Lefranc, Florence

2011-11-11

89

Drought-trigger ground-water levels and analysis of historical water-level trends in Chester County, Pennsylvania  

USGS Publications Warehouse

The Chester County observation-well network was established in 1973 through a cooperative agreement between the Chester County Water Resources Authority (CCWRA) and the U.S. Geological Survey. The network was established to monitor local ground-water levels, to determine drought conditions, and to monitor ground-water-level trends. Drought-warning and drought-emergency water-level triggers were determined for 20 of the 23 wells in the Chester County observation-well network. A statistical test to determine either rising or declining water-level trends was performed on data for all wells in the network. Water-level data from both of these wells showed a rising trend. A decrease in ground-water pumping in the area near these wells was probably the reason for the rise in water levels.

Schreffler, Curtis L.

1996-01-01

90

Predicting Risk from Radon in Source Waters from Water Quality Parameters  

EPA Science Inventory

Overall, 47 groundwater samples were collected from 45 small community water systems (CWSs) and analyzed for radon and other water quality constituents. In general, groundwater from unconsolidated deposits and sedimentary rocks had lower average radon levels (ranging from 223 to...

91

Probable high ground-water levels in Massachusetts  

USGS Publications Warehouse

Water-level records from an observation-well network are analyzed for utility in estimating probable high ground-water levels in three different geohydrologic environments in Massachusetts. Analyses were made of 83 observation wells with between 8 and 37 years of records. Maximum annual water levels occur most frequently in March and April. The maximum range of water levels equaled or exceeded at 10 percent of randomly selected sites is estimated to be 16 feet in till, 9.2 feet in sand and gravel on terraces, and 4.0 feet in sand and gravel in valleys. An approach to estimating probable high ground-water levels at construction sites is suggested. An estimate of the high water level at a site may be derived by solving the proportion in which the ratio of the potential water-level rise at a test site to the potential water-level rise at an observation well is equal to the ratio of the water-level range at the site to the historic water-level range at an observation well in a similar geohydrologic environment. Precise description of the probabilities of exceedence of estimates made by this approach with the data available has not been made. Assuming that the data are representative of the future, estimates would not be expected to be exceeded at more than 1 in 10 sites over a period of 10 years or longer. (USGS)

Frimpter, M. H.

1981-01-01

92

Towards quantification of uncertainty in predicting water quality failures in integrated catchment model studies.  

PubMed

This paper describes the development and application of a method for estimating uncertainty in the prediction of sewer flow quantity and quality and how this may impact on the prediction of water quality failures in integrated catchment modelling (ICM) studies. The method is generic and readily adaptable for use with different flow quality prediction models that are used in ICM studies. Use is made of the elicitation concept, whereby expert knowledge combined with a limited amount of data are translated into probability distributions describing the level of uncertainty of various input and model variables. This type of approach can be used even if little or no site specific data is available. Integrated catchment modelling studies often use complex deterministic models. To apply the results of elicitation in a case study, a computational reduction method has been developed in order to determine levels of uncertainty in model outputs with a reasonably practical level of computational effort. This approach was applied to determine the level of uncertainty in the number of water quality failures predicted by an ICM study, due to uncertainty associated with input and model parameters of the urban drainage model component of the ICM. For a small case study catchment in the UK, it was shown that the predicted number of water quality failures in the receiving water could vary by around 45% of the number predicted without consideration of model uncertainty for dissolved oxygen and around 32% for unionised ammonia. It was concluded that the potential overall levels of uncertainty in the ICM outputs could be significant. Any solutions designed using modelling approaches that do not consider uncertainty associated with model input and model parameters may be significantly over-dimensioned or under-dimensioned. With changing external inputs, such as rainfall and river flows due to climate change, better accounting for uncertainty is required. PMID:20569964

Schellart, A N A; Tait, S J; Ashley, R M

2010-05-11

93

Prediction of water intake and excretion flows in Holstein dairy cows under thermoneutral conditions.  

PubMed

The increase in the worldwide demand for dairy products, associated with global warming, will emphasize the issue of water use efficiency in dairy systems. The evaluation of environmental issues related to the management of animal dejections will also require precise biotechnical models that can predict effluent management in farms. In this study, equations were developed and evaluated for predicting the main water flows at the dairy cow level, based on parameters related to cow productive performance and diet under thermoneutral conditions. Two datasets were gathered. The first one comprised 342 individual measurements of water balance in dairy cows obtained during 18 trials at the experimental farm of Méjussaume (INRA, France). Predictive equations of water intake, urine and fecal water excretion were developed by multiple regression using a stepwise selection of regressors from a list of seven candidate parameters, which were milk yield, dry matter intake (DMI), body weight, diet dry matter content (DM), proportion of concentrate (CONC) and content of crude protein (CP) ingested with forage and concentrate (CPf and CPc, g/kg DM). The second dataset was used for external validation of the developed equations and comprised 196 water flow measurements on experimental lots obtained from 43 published papers related to water balance or digestibility measurements in dairy cows. Although DMI was the first predictor of the total water intake (TWI), with a partial r(2) of 0.51, DM was the first predictive parameter of free water intake (FWI), with a partial r(2) of 0.57, likely due to the large variability of DM in the first dataset (from 11.5 to 91.4 g/100 g). This confirmed the compensation between water drunk and ingested with diet when DM changes. The variability of urine volume was explained mainly by the CPf associated with DMI (r.s.d. 5.4 kg/day for an average flow of 24.0 kg/day) and that of fecal water was explained by the proportion of CONC in the diet and DMI. External validation showed that predictive equations excluding DMI as predictive parameters could be used for FWI, urine and fecal water predictions if cows were fed a well-known total mixed ration. It also appeared that TWI and FWI were underestimated when ambient temperature increased above 25°C and possible means of including climatic parameters in future predictive equations were proposed. PMID:23031565

Khelil-Arfa, H; Boudon, A; Maxin, G; Faverdin, P

2012-10-01

94

Measurement of Water Potential in Low-Level Waste Management.  

National Technical Information Service (NTIS)

The measurement of soil water is important to the shallow land burial of low-level waste. Soil water flow is the principle mechanism of radionuclide transport, allows the establishment of stabilizing vegetation and also governs the dissolution and release...

D. D. Gibson G. W. Gee R. R. Kirkham T. L. Jones

1982-01-01

95

Predicting and mapping soil available water capacity in Korea  

PubMed Central

The knowledge on the spatial distribution of soil available water capacity at a regional or national extent is essential, as soil water capacity is a component of the water and energy balances in the terrestrial ecosystem. It controls the evapotranspiration rate, and has a major impact on climate. This paper demonstrates a protocol for mapping soil available water capacity in South Korea at a fine scale using data available from surveys. The procedures combined digital soil mapping technology with the available soil map of 1:25,000. We used the modal profile data from the Taxonomical Classification of Korean Soils. The data consist of profile description along with physical and chemical analysis for the modal profiles of the 380 soil series. However not all soil samples have measured bulk density and water content at ?10 and ?1500 kPa. Thus they need to be predicted using pedotransfer functions. Furthermore, water content at ?10 kPa was measured using ground samples. Thus a correction factor is derived to take into account the effect of bulk density. Results showed that Andisols has the highest mean water storage capacity, followed by Entisols and Inceptisols which have loamy texture. The lowest water retention is Entisols which are dominated by sandy materials. Profile available water capacity to a depth of 1 m was calculated and mapped for Korea. The western part of the country shows higher available water capacity than the eastern part which is mountainous and has shallower soils. The highest water storage capacity soils are the Ultisols and Alfisols (mean of 206 and 205 mm, respectively). Validation of the maps showed promising results. The map produced can be used as an indication of soil physical quality of Korean soils.

Hong, Suk Young; Han, Kyung Hwa; Kim, Yihyun; Lee, Kyungdo

2013-01-01

96

Predicting and mapping soil available water capacity in Korea.  

PubMed

The knowledge on the spatial distribution of soil available water capacity at a regional or national extent is essential, as soil water capacity is a component of the water and energy balances in the terrestrial ecosystem. It controls the evapotranspiration rate, and has a major impact on climate. This paper demonstrates a protocol for mapping soil available water capacity in South Korea at a fine scale using data available from surveys. The procedures combined digital soil mapping technology with the available soil map of 1:25,000. We used the modal profile data from the Taxonomical Classification of Korean Soils. The data consist of profile description along with physical and chemical analysis for the modal profiles of the 380 soil series. However not all soil samples have measured bulk density and water content at -10 and -1500 kPa. Thus they need to be predicted using pedotransfer functions. Furthermore, water content at -10 kPa was measured using ground samples. Thus a correction factor is derived to take into account the effect of bulk density. Results showed that Andisols has the highest mean water storage capacity, followed by Entisols and Inceptisols which have loamy texture. The lowest water retention is Entisols which are dominated by sandy materials. Profile available water capacity to a depth of 1 m was calculated and mapped for Korea. The western part of the country shows higher available water capacity than the eastern part which is mountainous and has shallower soils. The highest water storage capacity soils are the Ultisols and Alfisols (mean of 206 and 205 mm, respectively). Validation of the maps showed promising results. The map produced can be used as an indication of soil physical quality of Korean soils. PMID:23646290

Hong, Suk Young; Minasny, Budiman; Han, Kyung Hwa; Kim, Yihyun; Lee, Kyungdo

2013-04-23

97

Evaluating and improving land surface model predictions using site-level observations  

NASA Astrophysics Data System (ADS)

We evaluated the performance of the Community Land Model, version 4, using site-level observations compiled through the North American Carbon Program Site Synthesis activity. Simulations were performed at 14 forest sites, and predictions of carbon, water, and energy fluxes and ecosystem state variables were compared with site observations. We found strong evidence that the initial model implementation of nutrient limitation was inadequate to capture diurnal variation in net carbon flux. By introducing a plant nutrient storage capacity, we were able to significantly improve the model performance at both diurnal and seasonal time scales, without adversely impacting water and energy flux predictions. We were also able to identify two other factors leading to poor performance at a subset of the sites, and suggest here some additional modifications to the cold-season sensitivity of photosynthesis and the implementation of the prorgnostic fire module.

Thornton, P. E.; Bisht, G.; Ricciuto, D. M.; NACP Site Synthesis Team

2011-12-01

98

Climatic change and Great Lakes water levels  

Microsoft Academic Search

World climatologists believe that increasing concentrations of CO2 in the earth's atmosphere will result in significant changes in the world's climate during the next century. In the present paper, the predictions of monthly temperature and precipitation for the Great Lakes basin derived from a current General Circulation (climatic change) Model, are incorporated into a hydrologie model of the Great Lakes

M. Sanderson; L. Wong

99

Prediction of final error level in learning and repetitive control  

NASA Astrophysics Data System (ADS)

Repetitive control (RC) is a field that creates controllers to eliminate the effects of periodic disturbances on a feedback control system. The methods have applications in spacecraft problems, to isolate fine pointing equipment from periodic vibration disturbances such as slight imbalances in momentum wheels or cryogenic pumps. A closely related field of control design is iterative learning control (ILC) which aims to eliminate tracking error in a task that repeats, each time starting from the same initial condition. Experiments done on a robot at NASA Langley Research Center showed that the final error levels produced by different candidate repetitive and learning controllers can be very different, even when each controller is analytically proven to converge to zero error in the deterministic case. Real world plant and measurement noise and quantization noise (from analog to digital and digital to analog converters) in these control methods are acted on as if they were error sources that will repeat and should be cancelled, which implies that the algorithms amplify such errors. Methods are developed that predict the final error levels of general first order ILC, of higher order ILC including current cycle learning, and of general RC, in the presence of noise, using frequency response methods. The method involves much less computation than the corresponding time domain approach that involves large matrices. The time domain approach was previously developed for ILC and handles a certain class of ILC methods. Here methods are created to include zero-phase filtering that is very important in creating practical designs. Also, time domain methods are developed for higher order ILC and for repetitive control. Since RC and ILC must be implemented digitally, all of these methods predict final error levels at the sample times. It is shown here that RC can easily converge to small error levels between sample times, but that ILC in most applications will have large and diverging intersample error if in fact zero error is reached at the sample times. This is independent of the ILC law used, and is purely a property of the physical system. Methods are developed to address this issue.

Levoci, Peter A.

100

Water hammer prediction and control: the Green's function method  

NASA Astrophysics Data System (ADS)

By Green's function method we show that the water hammer (WH) can be analytically predicted for both laminar and turbulent flows (for the latter, with an eddy viscosity depending solely on the space coordinates), and thus its hazardous effect can be rationally controlled and minimized. To this end, we generalize a laminar water hammer equation of Wang et al. (J. Hydrodynamics, B2, 51, 1995) to include arbitrary initial condition and variable viscosity, and obtain its solution by Green's function method. The predicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.

Xuan, Li-Jun; Mao, Feng; Wu, Jie-Zhi

2012-04-01

101

Ground-water levels and quality data for Georgia, 1978  

USGS Publications Warehouse

Mean water levels in wells across Georgia were from 0.25 foot higher to 11.4 feet lower in 1978 than in 1977, and in some areas were the lowest on record. Water levels in the principal artesian aquifer underwent a long-term decline during the period 1969-78. In some areas water levels dropped more than 10 feet. Wells tapping the Clayton Limestone in the Albany area showed a long-term decline during the period 1969-78, and in some wells water levels dropped more than 20 feet. Water levels in the Cretaceous aquifer system showed little fluctuation during 1978; however, in a well located in Chattahoochee County, water levels declined 4.4 feet during 1969-78. In the Piedmont area mean water levels remained the same to 2.2 feet lower in 1978 than in 1977, and showed no long-term trend. Chloride concentrations in the principal artesian aquifer in the Savannah area remained stable and in the Brunswick area continued to rise during 1978. Daily mean water-level fluctuations and trends for 1978 and fluctuations of the monthly mean water level for the previous 10 years are shown in hydrographs of 33 selected observation wells in Georgia. Chloride concentrations in 11 wells in the Savannah and Brunswick areas are shown in graphs of monthly values over the previous 10 years. A short narrative explains fluctuations and trends in each of the hydrographs and chloride concentration graphs shown. (Woodard-USGS)

Clarke, J. S.; Hester, W. G.; O'Byrne, M. P.

1979-01-01

102

PERSPECTIVE FROM WATER LEVEL, SOUTHEAST BY 165 DEGREES. Wright's ...  

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

PERSPECTIVE FROM WATER LEVEL, SOUTHEAST BY 165 DEGREES. - Wright's Bridge, Spanning Sugar River, former Boston & Maine Railroad (originally Concord & Claremont Railroad), Claremont, Sullivan County, NH

103

Predicting oxygen transfer and water flow rate in airlift aerators  

Microsoft Academic Search

Water flow rate, gas-phase holdup, and dissolved oxygen (DO) profiles are measured in a full-scale airlift aerator as a function of applied air flow rate. A model that predicts oxygen transfer based on discrete-bubble principles is applied. The riser DO profiles are used to calculate the initial bubble size. The range of calculated bubble diameters obtained using the model is

Vickie L Burris; Daniel F McGinnis; John C Little

2002-01-01

104

Groundwater-level prediction using multiple linear regression and artificial neural network techniques: a comparative assessment  

NASA Astrophysics Data System (ADS)

The potential of multiple linear regression (MLR) and artificial neural network (ANN) techniques in predicting transient water levels over a groundwater basin were compared. MLR and ANN modeling was carried out at 17 sites in Japan, considering all significant inputs: rainfall, ambient temperature, river stage, 11 seasonal dummy variables, and influential lags of rainfall, ambient temperature, river stage and groundwater level. Seventeen site-specific ANN models were developed, using multi-layer feed-forward neural networks trained with Levenberg-Marquardt backpropagation algorithms. The performance of the models was evaluated using statistical and graphical indicators. Comparison of the goodness-of-fit statistics of the MLR models with those of the ANN models indicated that there is better agreement between the ANN-predicted groundwater levels and the observed groundwater levels at all the sites, compared to the MLR. This finding was supported by the graphical indicators and the residual analysis. Thus, it is concluded that the ANN technique is superior to the MLR technique in predicting spatio-temporal distribution of groundwater levels in a basin. However, considering the practical advantages of the MLR technique, it is recommended as an alternative and cost-effective groundwater modeling tool.

Sahoo, Sasmita; Jha, Madan K.

2013-10-01

105

Metallic Phase of Water Ice Predicted at Megabar Pressures  

NASA Astrophysics Data System (ADS)

We predict water ice to attain two new crystal structures with Pbca and Cmcm symmetry at 7.6 and 15.5 Mbar, respectively [Phys. Rev. Lett. 105 (2010) 195701]. With density functional calculations, we analyze the structural and electronic properties of these phases at zero temperature. The Pbca phase, like the known high-pressure ice phases VII, VIII, X and Pbcm, is insulating and consists of two interpenetrating hydrogen bonded networks, but the Cmcm phase is metallic and consists of corrugated sheets of H and O atoms. The H atoms are squeezed into octahedral positions between next-nearest O atoms while they occupy tetrahedral positions between nearest O atoms in lower-pressure phases. Our predictions may be testable with ramp compression experiments that can reach megabar pressures at lower temperatures than conventional shock wave experiments. The predicted insulator-to-metal transition would lead to an increase in reflectivity that can be measured with spectroscopic techniques.

Militzer, Burkhard; Wilson, Hugh

2011-03-01

106

Water levels in the Yucca Mountain area, Nevada, 1994  

SciTech Connect

Water levels were monitored in 28 wells in the Yucca Mountain area, Nevada, during 1994. Twelve wells representing 13 intervals were monitored periodically, generally on a monthly basis, 6 wells representing 10 intervals were monitored hourly, and 10 wells representing 13 intervals were monitored both periodically and hourly. All wells monitor water levels in Tertiary volcanic rocks, except one, that monitors water levels in Paleozoic carbonate rocks. Water levels were measured using calibrated steel tapes, a multiconductor cable unit, and pressure transducers. Water-level altitudes in the Tertiary volcanic rocks ranged from about 728 to about 1,034 meters above sea level during 1994. The mean-annual water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 753 meters above sea level during 1994. Water levels were only an average of about 0.01 meters lower than 1993 water levels. All data were acquired in accordance with a quality-assurance program to support the reliability of the data.

Graves, R.P.; Tucci, P.; Goemaat, R.L.

1996-12-31

107

Ecology predicts levels of genetic differentiation in neotropical birds.  

PubMed

Despite the theoretical link between the ecology and the population genetics of species, little empirical evidence is available that corroborates the association. Here, we examined genetic variation in 40 codistributed species of lowland Neotropical rain forest birds that have populations isolated on either side of the Andes, the Amazon River, and the Madeira River. We found widely varying levels of genetic divergence among these taxa across the same biogeographic barriers. Our investigation of the extent to which ecological traits predicted the amount of cross-barrier divergence revealed a strongly significant relationship between the forest stratum at which a species forages and the level of cross-barrier genetic differentiation. Canopy species had statistically lower genetic divergence values across the Andes and the two Amazonian rivers than did understory birds. We hypothesize that the association reflects an effect of dispersal propensity, which is greater in canopy birds, on the movement of alleles among demes (i.e., migration) and, consequently, on the interdemic proportion of the genetic variance. Differences in dispersal propensity may also explain the observation that understory species contain a significantly greater number of subspecies than do canopy species. This result indicates that higher rates of diversification may occur in lineages with lower dispersal propensity. PMID:19627230

Burney, Curtis W; Brumfield, Robb T

2009-09-01

108

Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data  

SciTech Connect

This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate baro-metric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

Spane, Frank A.

1999-12-16

109

Impact of Plumbing Age on Copper Levels in Drinking Water  

EPA Science Inventory

Theory and limited practical experiences suggest that higher copper levels in drinking water tap samples are typically associated with newer plumbing systems, and levels decrease with increasing plumbing age. Past researchers have developed a conceptual model to explain the ?agin...

110

Animating ground water levels with Excel.  

PubMed

This note describes the use of Microsoft Excel macros (programs written in Excel's internal language, Visual Basic for Applications) to create simple onscreen animations of transient ground water data within Excel. Compared to many specialized visualization software packages, the use of Excel macros is much cheaper, much simpler, and can rapidly be learned. The Excel macro can also be used to create individual GIF files for each animation frame. This series of frames can then be used to create an AVI video file using any of a number of graphics packages, such as Corel PhotoPaint. The technique is demonstrated through a macro that animates changes in the elevation of a water table along a transect over several years. PMID:12873018

Shikaze, Steven G; Crowe, Allan S

111

Hydrological and water management related applications of long term meteorological prediction  

NASA Astrophysics Data System (ADS)

Seasonal forecast activities at the Hungarian Meteorological Service have a long history. Published forecasts used to be the results of different statistical procedures based on clustering of different typical sequences. Long term meteorological forecasts of recent years are based on ECMWF long term projections. Those are interpreted and downscaled for the territory of Hungary and Danube catchments. 1 - 6-month forecasts of 2-m temperatures and precipitation are used for hydrological projections. Seasonal forecasts of Lake Balaton water budget, monthly mean streamflow and low water estimates for central Danube are targeted. The catchments comprising the river system are situated in various climatological and geo-morphological settings across the region. Skill score of the projections are investigated for average and extreme conditions. The five year period in between 2000-2004 resulted dry conditions over the Balaton drainage area. The continuous extreme low values in water budget of the Lake led to significant drop of water levels. Starting with the summer of 2000 water level of the Lake remained most time below the lower regulation level. Typical patterns of water level fluctuation remained in this dry period (rises during cold half year, decreases during warm half year). However the series of annual deficits are expressed in lower and lower annual minimum of water levels. The accumulated deficit of natural water budget relative to multi-annual average reached a maximum for lake surface without any precedent for the period of water budget accounting. Danube monthly flow, minimum flow and water level predictions for the period 1984-2009 are also analysed.

Varga, György; Body, Károly; Hunyady, Adrienn; Balint, Gabor

2010-05-01

112

Statistical and Biophysical Models for Predicting Total and Outdoor Water Use in Los Angeles  

NASA Astrophysics Data System (ADS)

Modeling water demand is a complex exercise in the choice of the functional form, techniques and variables to integrate in the model. The goal of the current research is to identify the determinants that control total and outdoor residential water use in semi-arid cities and to utilize that information in the development of statistical and biophysical models that can forecast spatial and temporal urban water use. The City of Los Angeles is unique in its highly diverse socio-demographic, economic and cultural characteristics across neighborhoods, which introduces significant challenges in modeling water use. Increasing climate variability also contributes to uncertainties in water use predictions in urban areas. Monthly individual water use records were acquired from the Los Angeles Department of Water and Power (LADWP) for the 2000 to 2010 period. Study predictors of residential water use include socio-demographic, economic, climate and landscaping variables at the zip code level collected from US Census database. Climate variables are estimated from ground-based observations and calculated at the centroid of each zip code by inverse-distance weighting method. Remotely-sensed products of vegetation biomass and landscape land cover are also utilized. Two linear regression models were developed based on the panel data and variables described: a pooled-OLS regression model and a linear mixed effects model. Both models show income per capita and the percentage of landscape areas in each zip code as being statistically significant predictors. The pooled-OLS model tends to over-estimate higher water use zip codes and both models provide similar RMSE values.Outdoor water use was estimated at the census tract level as the residual between total water use and indoor use. This residual is being compared with the output from a biophysical model including tree and grass cover areas, climate variables and estimates of evapotranspiration at very high spatial resolution. A genetic algorithm based model (Shuffled Complex Evolution-UA; SCE-UA) is also being developed to provide estimates of the predictions and parameters uncertainties and to compare against the linear regression models. Ultimately, models will be selected to undertake predictions for a range of climate change and landscape scenarios. Finally, project results will contribute to a better understanding of water demand to help predict future water use and implement targeted landscaping conservation programs to maintain sustainable water needs for a growing population under uncertain climate variability.

Mini, C.; Hogue, T. S.; Pincetl, S.

2012-04-01

113

Removal of barometric pressure response from water level data  

Microsoft Academic Search

The removal from water level data fluctuations due to barometric forcing at subtidal frequencies is studied using transfer functions. In a poorly confined well-aquifer system these transfer functions are, in general, dependent upon air diffusivity through the unsaturated zone and diffusivity from the water table into the unsaturated zone. The stability in time of estimated transfer functions from selected water

Eddie G. Quilty; Evelyn A. Roeloffs

1991-01-01

114

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

115

Gastric Cancer Mortality and Nitrate Levels in Wisconsin Drinking Water  

Microsoft Academic Search

The association between nitrate levels in public and private sources of drinking water and gastric cancer mortality in Wisconsin was investigated in a case-control study. All gastric cancer deaths of Wisconsin residents from 1982 through 1985 were compared with deaths from other causes (controls), and nitrate levels in the home drinking water of these residents were determined. Nitrate measures for

John J. Rademacher; Theresa B. Young; Marty S. Kanarek

1992-01-01

116

Water Levels and Total Phosphorus in Lake Okeechobee  

Microsoft Academic Search

Pelagic total phosphorus (TP) concentrations in Lake Okeechobee were shown previously to be correlated with lake water levels, possibly due to littoral flooding and subsequent P release from vegetation (Canfield and Hoyer 1988). The present paper reviews the research to test this and other hypotheses to explain the water level – TP relationship. Research in the littoral region indicates that

Karl E. Havens

1997-01-01

117

Water Level Dynamics in the Great Lakes of North America  

Microsoft Academic Search

Anthropogenic as well as natural fluctuations such as precipitation, runoff, snowmelt, retention time, evaporation, and outflow all contribute to water levels observed in the Great Lakes. Verified hourly water level data for five stations in Lake Michigan and four stations in Lake Superior were obtained from NOAA and examined. For each station, an hourly time series ranging from 20 to

J. R. Smigelski; S. F. Tebbens; C. C. Barton

2007-01-01

118

Water properties of hydrogel contact lens materials: a possible predictive model for corneal desiccation staining.  

PubMed

A set of properties of the water contained within hydrogel contact lens materials was determined with the aim of developing a model which would predict the propensity of a hydrogel contact lens material to induce corneal desiccation staining. We postulated that materials containing a larger proportion of water with the properties of bulk water would tend to induce corneal desiccation more readily than materials with the same overall water content but containing a larger proportion of water that interacts strongly with the polymer. The water structure [as measured by differential scanning calorimetry (DSC)] and the permeabilities of water and glucose were determined for a series of commercial hydrogel lenses. Both glucose permeability and DSC measurements are sensitive indicators of water structure and able to distinguish between various materials. To illustrate the potential of our model, the results of a short-term clinical study are presented. Lower levels of staining were noted for a material with a lower glucose permeability and a larger amount of water melting below 0 degrees C than for a control lens, even though both materials were similar in water content and water permeability. Further clinical studies are needed to validate this model. PMID:7508759

Mirejovsky, D; Patel, A S; Young, G

1993-11-01

119

Predicting soil water, tile drainage, and runoff in a mole?tile drained soil  

Microsoft Academic Search

There has been considerable intensification of agriculture on mole?tile drained soils in New Zealand. Management techniques and tools are needed for predicting and understanding water and nutrient transport. While simple water balance models have been effective in estimating soil water deficit, such models cannot differentiate between the different water loss mechanisms. More complex water?transport models include the ability to predict

V. O. Snow; D. J. Houlbrooke; N. I. Huth

2007-01-01

120

Sea level rise and water storage on land  

NSDL National Science Digital Library

Climate data was used to model the relationship between sea level rise and the loss of water stored in soils and snowpack on land. It was found that water stored on land did not make any lasting contribution to sea level rise during the 50 year period, although strong variation in precipitation and subsequent runoff, particularly in the tropics, caused sea level to fluctuate every ten years or so.

Al., Duc E.; Agu

121

The Constant Levelers: Water, Ice, and Gravity  

NSDL National Science Digital Library

This site has information about the work of three of the agents of erosion in the Northern Cascade Range. Since much of the range is made up of exotic terrains that probably did not evolve on the same spot on the Earth as the present North Cascades, the geologists confine their view to some time since the earliest Tertiary. Within that time frame, they can speculatively recreate the North Cascade scene and ponder its erosional history. The erosional work of rivers has constantly been altered by volcanic activity and whatever drainage pattern was established. It was profoundly altered about 35 million years ago by the renewed volcanic activity of the Cascade Volcanic Arc. A section about how rivers erode describes differential erosion, stream capture, and base level. The section about glaciers explains how they are formed, how they do their work, and what is left behind. The section about the work of gravity focuses on creep and landslides.

122

Parameter estimation techniques and uncertainty in ground water flow model predictions  

SciTech Connect

Quantification of uncertainty in predictions of nuclear waste repository performance is a requirement of Nuclear Regulatory Commission regulations governing the licensing of proposed geologic repositories for high-level radioactive waste disposal. One of the major uncertainties in these predictions is in estimating the ground-water travel time of radionuclides migrating from the repository to the accessible environment. The cause of much of this uncertainty has been attributed to a lack of knowledge about the hydrogeologic properties that control the movement of radionuclides through the aquifers. A major reason for this lack of knowledge is the paucity of data that is typically available for characterizing complex ground-water flow systems. Because of this, considerable effort has been put into developing parameter estimation techniques that infer property values in regions where no measurements exist. Currently, no single technique has been shown to be superior or even consistently conservative with respect to predictions of ground-water travel time. This work was undertaken to compare a number of parameter estimation techniques and to evaluate how differences in the parameter estimates and the estimation errors are reflected in the behavior of the flow model predictions. That is, we wished to determine to what degree uncertainties in flow model predictions may be affected simply by the choice of parameter estimation technique used. 3 refs., 2 figs.

Zimmerman, D.A. (GRAM, Inc., Albuquerque, NM (USA)); Davis, P.A. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01

123

Effects of water turbidity and salt concentration levels on penetration of solar radiation under water  

Microsoft Academic Search

Two large, outdoor tanks were constructed in order to investigate the effects of water turbidity and salt concentration levels at various depths of water on penetration of solar radiation. These experiments were followed by a laboratory investigation that measured spectral transmittance and the extinction coefficient of water at different salt concentrations and turbidity levels. Both the outdoor and laboratory results

J. Wang; J. Seyed-Yagoobi

1994-01-01

124

Sex-typing of the Water-Level Task: There is More than Meets the Eye  

Microsoft Academic Search

It has often been reported that male subjects surpass female subjects in the mastery of gravitational horizontality in the water-level task, although it has yet to be established whether or not these subjects perceive it as calling for gender-specific abilities. In the present study, it was predicted that more subjects would judge this task to be masculine than either feminine

Michèle Robert

1990-01-01

125

Forecast Verification for Eta Model Winds Using Lake Erie Storm Surge Water Levels  

Microsoft Academic Search

This article has two purposes. The first is to describe how the Great Lakes Coastal Forecasting System (GLCFS) can be used to validate wind forecasts for the Great Lakes using observed and forecast water levels. The second is to evaluate how well two versions (40 km and 29 km) of the numerical weather prediction step-coordinate Eta Model are able to

William P. O’Connor; David J. Schwab; Gregory A. Lang

1999-01-01

126

Unraveling uncertainties : the effect of hydraulic roughness on design water levels in river models  

Microsoft Academic Search

Flooding is a serious threat in many regions in the world and is a problem of international interest. Hydrodynamic models are used for the prediction of flood water levels to support flood safety and are often applied in a deterministic way. However, the modelling of river processes involves numerous uncertainties. Previous research has shown that the hydraulic roughness is one

Jord Jurriaan Warmink

2011-01-01

127

Prediction of water surface elevation of Great Salt Lake using Support Vector Machine  

NASA Astrophysics Data System (ADS)

Record breaking rises of Great Salt Lake (GSL) water levels that were observed in the period 1982-1987 resulted in severe economic impact to the State of Utah. Rising lake levels caused flooding that damaged highways, railways, recreation facilities and industries located in exposed lake bed. Prediction of GSL water levels necessitates the development of a model for accurate predictions of such levels in order to reduce or prevent economic loss due to flooding as happened in the past. A data-driven model, whose intent is to determine the relationship between inputs and outputs without knowing underlying physical process, was used in this project. A data-driven model can bridge the gap between classical regression-based and physically-based hydrological models. A Support Vector Machines (SVM) was used to predict water surface elevation of the GSL. The SVM-based reconstruction was used to develop time series forecast for multiple lead times. The model is able to extract the dynamics of the system by using only a few observed data points for training. The reliability of the algorithm in learning and forecasting the dynamics of the system was tested by changing two parameters: the integer time lag and the dimension (d) of the system. Parameter tau models the delay in which the dynamics unfolds by creating vectors of dimension d out of single measurements. For a given set of parameters tau and d, the discrepancy between observation and prediction is reduced by changing the cost parameter and a parameter called epsilon that controls the width of the SVM insensitive zone. All the data points within the epsilon insensitive zone are neglected in the SVM analysis. The analysis was performed for two time periods. The period of 1982 to 1987 was used to test the model performance in predicting the corresponding dramatic rise of GSL elevation. The period of 1987 to 2008 was used to test the performance of model for the normal water level rise and fall of the GSL. This analysis was conducted on both the North and South arms of the lake. After testing the model for different combinations of integer lag and dimension d, it was found that these data-driven models made fairly precise prediction based on only observed water surface elevation data.

Shrestha, N. K.; Urroz, G.

2009-12-01

128

Sea-Level Rise: Implications for Water Resources Management  

Microsoft Academic Search

Globally, sea level has been rising for more than the last one hundred years, and is expected to do so into the foreseeable future, and at an accelerating rate. The direct influences of sea-level rise on water resources come principally from the following: new or accelerated coastal erosion; more extensive coastal inundation and higher levels of sea flooding; increases in

John E. Hay; Nobuo Mimura

2005-01-01

129

Water jump reorientation: from theoretical prediction to experimental observation.  

PubMed

Liquid water is remarkably labile in reorganizing its hydrogen-bond (HB) network through the breaking and forming of HBs. This rapid restructuring, which occurs on the picosecond time scale, is critical not only for many of the pure liquid's special features but also for a range of aqueous media phenomena, including chemical reactions and protein activity. An essential part of the HB network reorganization is water molecule reorientation, which has long been described as Debye rotational diffusion characterized by very small angular displacements. Recent theoretical work, however, has presented a starkly contrasting picture: a sudden, large-amplitude jump mechanism, in which the reorienting water molecule rapidly exchanges HB partners in what amounts to an activated chemical reaction. In this Account, we first briefly review the jump mechanism and then discuss how it is supported by a series of experiments. These studies range from indirect indications to direct characterization of the jumps through pioneering two-dimensional infrared spectroscopy (2D-IR), the power of which accords it a special focus here. The scenarios in which experimental signatures of the jump mechanism are sought increase in complexity throughout the Account, beginning with pure water. Here 2D-IR in combination with theory can give a glimpse of the jumps, but the tell-tale markers are not pronounced. A more fruitful arena is provided by aqueous ionic solutions. The difference between water-water and water-anion HB strengths provides the experimental handle of differing OH stretch frequencies; in favorable cases, the kinetic exchange of a water between these two sites can be monitored. Sole observation of this exchange, however, is insufficient to establish the jump mechanism. Fortunately, 2D-IR with polarized pulses has demonstrated that HB exchange is accompanied by significant angular displacement, with an estimated jump angle similar to theoretical estimates. The Janus-like character of amphiphilic solutes, with their hydrophobic and hydrophilic faces, presents a special challenge for theory and experiment. Here a consensus on the 2D-IR interpretation has not yet been achieved; this lack of accord impedes the understanding of, for example, biochemical solutes and interfaces. We argue that the influence of hydrophobic groups on water jumps is only modest and well accounted for by an excluded volume effect in the HB exchange process. Conversely, hydrophilic groups have an important influence when their HB strength with water differs significantly from that of the water-water HB. The power of 2D-IR is argued to be accompanied by subtleties that can lead to just the opposite and, in our view, erroneous conclusion. We close with a prediction that a hydrophobic surface offers an arena in which the dynamics of "dangling" water OHs, bereft of a HB, could provide a 2D-IR confirmation of water jumps. PMID:21749157

Laage, Damien; Stirnemann, Guillaume; Sterpone, Fabio; Hynes, James T

2011-07-13

130

Prediction of functional residues in water channels and related proteins.  

PubMed Central

In this paper, we present an updated classification of the ubiquitous MIP (Major Intrinsic Protein) family proteins, including 153 fully or partially sequenced members available in public databases. Presently, about 30 of these proteins have been functionally characterized, exhibiting essentially two distinct types of channel properties: (1) specific water transport by the aquaporins, and (2) small neutral solutes transport, such as glycerol by the glycerol facilitators. Sequence alignments were used to predict amino acids and motifs discriminant in channel specificity. The protein sequences were also analyzed using statistical tools (comparisons of means and correspondence analysis). Five key positions were clearly identified where the residues are specific for each functional subgroup and exhibit high dissimilar physico-chemical properties. Moreover, we have found that the putative channels for small neutral solutes clearly differ from the aquaporins by the amino acid content and the length of predicted loop regions, suggesting a substrate filter function for these loops. From these results, we propose a signature pattern for water transport.

Froger, A.; Tallur, B.; Thomas, D.; Delamarche, C.

1998-01-01

131

Quantification of umu genotoxicity level of urban river water.  

PubMed

In recent years, the request of environmental safety management for carcinogenic substances, mutagenic substances and/or reproductive toxicity substances (CMR) has increased. This study focused on clarifying the genotoxicity level of environmental water and its release source by using the umu test provided in ISO13829. Although a genotoxicity index "induction ratio (IR)" is used in ISO13829, we normalised it to make it possible to compare various environmental water quantitatively to each other as a new index "genotoxic activity (GA=(IR-1)/Dose)". Sample water was collected and concentrated to 100 times or 1,000 times by a solid phase extraction method. As the test results, it was found that GA level in actual river water varied widely from less than the determination limit of 23 [1/L] to 1,100 [1/L] by quantitative comparison, and the value was also equivalent to more than 50 times the level of tap water. The GA level of household wastewater was not so high, but the levels of treated water from wastewater treatment plant (WTP) were from 220 [1/L] to 3,200 [1/L]. Raw sewage of some WTP shows high level genotoxicity. A part of genotoxicity substances, for example 50%, could be removed by conventional wastewater treatment, but it was not enough to reduce the water environmental load of genotoxicity. PMID:21278461

Kameya, T; Nagato, T; Nakagawa, K; Yamashita, D; Kobayashi, T; Fujie, K

2011-01-01

132

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.  

PubMed

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area. PMID:14982159

Chung, W S; Yu, M J; Lee, H D

2004-01-01

133

Dissolved oxygen levels in estuarine and coastal waters around Ireland  

Microsoft Academic Search

This paper presents the status of summer oxygen conditions in estuarine and coastal waters around Ireland between 2003 and 2007. Of the 95 water bodies surveyed, 85 had oxygen levels sufficient to support aquatic life. This corresponds to a surface area of 3125km2 or 99.4% of the total area assessed. Ten water bodies, representing a surface area of 20.2km2, were

Shane O’Boyle; Georgina McDermott; Robert Wilkes

2009-01-01

134

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

135

Low-level measurements of tritium in water  

Microsoft Academic Search

Using a liquid scintillation counter, an experimental procedure for measuring low-level activity concentrations of tritium in environmental water has been developed by our laboratory, using the electrolytic tritium enrichment. Additionally, some quality tests were applied in order to assure the goodness of the method. Well-known water samples collected in the Tagus River (West of Spain) and the Danube River (Bulgaria),

M. Villa; G. Manjón

2004-01-01

136

Geomorphological evidence of water level changes in Nepenthes Mensae, Mars  

Microsoft Academic Search

In the western sector of Nepenthes Mensae, Mars, there are some geomorphological features that could be related to a standing water sheet in the area, such as fluvial terraces, deltas and shorelines. A detailed analysis of these features reveals two variations in water level, probably related to tectonic processes, as suggested by the existence of a fissural volcano at this

Miguel Ángel de Pablo; Andrea Pacifici

2008-01-01

137

Geomorphological evidence of water level changes in Nepenthes Mensae, Mars  

NASA Astrophysics Data System (ADS)

In the western sector of Nepenthes Mensae, Mars, there are some geomorphological features that could be related to a standing water sheet in the area, such as fluvial terraces, deltas and shorelines. A detailed analysis of these features reveals two variations in water level, probably related to tectonic processes, as suggested by the existence of a fissural volcano at this site.

de Pablo, Miguel Ángel; Pacifici, Andrea

2008-08-01

138

Responses of wetland plants to ammonia and water level  

Microsoft Academic Search

Constructed wetland systems receiving animal wastewater may enhance water quality when designed, operated, and maintained properly. In the case of wetlands designed to treat animal waste, system effectiveness may be limited by high ammonia concentrations and inundation, conditions that can adversely affect macrophytic vegetation. We conducted a 4-month greenhouse experiment to assess the impact of ammonia concentration and water level

Ernest Clarke; Andrew H. Baldwin

2002-01-01

139

Enhancing resilience in great lakes water levels management  

Microsoft Academic Search

Great Lakes water levels management has been the focus of major studies by the Canada?U.S. International Joint Commission (IJC) since 1964. The main reason for this activity is the economic significance of lake levels fluctuations to navigation, hydro?electric power generation, recreation, shoreline erosion, industrial and municipal water supply and wildlife. Reviews of public policies for Great Lakes shoreline management indicate

A. P. Lino Grima

1993-01-01

140

Water clusters on graphite: methodology for quantum chemical a priori prediction of reaction rate constants.  

PubMed

The properties, interactions, and reactions of cyclic water clusters (H(2)O)(n=1-5) on model systems for a graphite surface have been studied using pure B3LYP, dispersion-augmented density functional tight binding (DFTB-D), and integrated ONIOM(B3LYP:DFTB-D) methods. Coronene C(24)H(12) as well as polycircumcoronenes C(96)H(24) and C(216)H(36) in monolayer, bilayer, and trilayer arrangements were used as model systems to simulate ABA bulk graphite. Structures, binding energies, and vibrational frequencies of water clusters on mono- and bilayer graphite models have been calculated, and structural changes and frequency shifts due to the water cluster-graphite interactions are discussed. ONIOM(B3LYP:DFTB-D) with coronene and water in the high level and C(96)H(24) in the low level mimics the effect of extended graphite pi-conjugation on the water-graphite interaction very reasonably and suggests that water clusters only weakly interact with graphite surfaces, as suggested by the fact that water is an excellent graphite lubricant. We use the ONIOM(B3LYP:DFTB-D) method to predict rate constants for model pathways of water dissociative adsorption on graphite. Quantum chemical molecular dynamics (QM/MD) simulations of water clusters and water addition products on the C(96)H(24) graphite model are presented using the DFTB-D method. A three-stage strategy is devised for a priori investigations of high temperature corrosion processes of graphite surfaces due to interaction with water molecules and fragments. PMID:16866408

Xu, S; Irle, S; Musaev, D G; Lin, M C

2005-10-27

141

Expanded prediction equations of human sweat loss and water needs.  

PubMed

The Institute of Medicine expressed a need for improved sweating rate (msw) prediction models that calculate hourly and daily water needs based on metabolic rate, clothing, and environment. More than 25 years ago, the original Shapiro prediction equation (OSE) was formulated as msw (g.m(-2).h(-1))=27.9.Ereq.(Emax)(-0.455), where Ereq is required evaporative heat loss and Emax is maximum evaporative power of the environment; OSE was developed for a limited set of environments, exposures times, and clothing systems. Recent evidence shows that OSE often overpredicts fluid needs. Our study developed a corrected OSE and a new msw prediction equation by using independent data sets from a wide range of environmental conditions, metabolic rates (rest to 500 observations) by using a variety of metabolic rates over a range of environmental conditions (ambient temperature, 15-46 degrees C; water vapor pressure, 0.27-4.45 kPa; wind speed, 0.4-2.5 m/s), clothing, and equipment combinations and durations (2-8 h). Data are expressed as grams per square meter per hour and were analyzed using fuzzy piecewise regression. OSE overpredicted sweating rates (P<0.003) compared with observed msw. Both the correction equation (OSEC), msw=147.exp (0.0012.OSE), and a new piecewise (PW) equation, msw=147+1.527.Ereq-0.87.Emax were derived, compared with OSE, and then cross-validated against independent data (21 males and 9 females; >200 observations). OSEC and PW were more accurate predictors of sweating rate (58 and 65% more accurate, P<0.01) and produced minimal error (standard error estimate<100 g.m(-2).h(-1)) for conditions both within and outside the original OSE domain of validity. The new equations provide for more accurate sweat predictions over a broader range of conditions with applications to public health, military, occupational, and sports medicine settings. PMID:19407259

Gonzalez, R R; Cheuvront, S N; Montain, S J; Goodman, D A; Blanchard, L A; Berglund, L G; Sawka, M N

2009-04-30

142

Monitoring of Low-Level Virus in Natural Waters  

PubMed Central

The insoluble polyelectrolyte technique for concentrating virus is extended to extremely low virus levels. The effectiveness of this method employing a coliphage T2 model is a constant 20% over a range of virus levels from 103 to 10?4 plaque-forming units/ml. The efficiency of the method is dependent upon pH control during the concentration phase. Although the study was initiated to develop a method for quantitating the effectiveness of water and wastewater treatment methods for the removal of viruses from waters at low concentrations, the potential of the technique for efficient monitoring of natural waters is apparent.

Sorber, Charles A.; Sagik, Bernard P.; Malina, Joseph F.

1971-01-01

143

RADIOLYTIC HYDROGEN GENERATION INSAVANNAH RIVER SITE (SRS) HIGH LEVEL WASTETANKS COMPARISON OF SRS AND HANFORDMODELING PREDICTIONS  

SciTech Connect

In the high level waste tanks at the Savannah River Site (SRS), hydrogen is produced continuously by interaction of the radiation in the tank with water in the waste. Consequently, the vapor spaces of the tanks are purged to prevent the accumulation of H{sub 2} and possible formation of a flammable mixture in a tank. Personnel at SRS have developed an empirical model to predict the rate of H{sub 2} formation in a tank. The basis of this model is the prediction of the G value for H{sub 2} production. This G value is the number of H{sub 2} molecules produced per 100 eV of radiolytic energy absorbed by the waste. Based on experimental studies it was found that the G value for H{sub 2} production from beta radiation and from gamma radiation were essentially equal. The G value for H{sub 2} production from alpha radiation was somewhat higher. Thus, the model has two equations, one for beta/gamma radiation and one for alpha radiation. Experimental studies have also indicated that both G values are decreased by the presence of nitrate and nitrite ions in the waste. These are the main scavengers for the precursors of H{sub 2} in the waste; thus the equations that were developed predict G values for hydrogen production as a function of the concentrations of these two ions in waste. Knowing the beta/gamma and alpha heat loads in the waste allows one to predict the total generation rate for hydrogen in a tank. With this prediction a ventilation rate can be established for each tank to ensure that a flammable mixture is not formed in the vapor space in a tank. Recently personnel at Hanford have developed a slightly different model for predicting hydrogen G values. Their model includes the same precursor for H{sub 2} as the SRS model but also includes an additional precursor not in the SRS model. Including the second precursor for H{sub 2} leads to different empirical equations for predicting the G values for H{sub 2} as a function of the nitrate and nitrite concentrations in the waste. The difference in the two models has led to the questions of how different are the results predicted by the two models and which model predicts the more conservative (larger) G values. More conservative G values would predict higher H{sub 2} generation rates that would require higher ventilation rates in the SRS tanks. This report compares predictions based on the two models at various nitrate and nitrite concentrations in the SRS HLW tanks for both beta/gamma and for alpha radiation. It also compares predicted G values with those determined by actually measuring the H{sub 2} production from four SRS HLW tanks (Tanks 32H, 35H, 39H, and 42H). Lastly, the H{sub 2} generation rates predicted by the two models are compared for the 47 active SRS high level waste tanks using the most recent tank nitrate and nitrite concentrations and the beta/gamma and alpha heat loads for each tank. The predictions of the models for total H{sub 2} generation rates from the 47 active SRS waste were, for the most part, similar. For example, the predictions for both models applied to 25 tanks agreed within {+-}10% of each other. For the remaining 22 tanks, the SRS prediction was more conservative for 9 tanks (maximum 29% higher) and the Hanford prediction was more conservative for 13 tanks (maximum 19% higher). When comparing G values predicted by the equations presuming only alpha radiation or only beta/gamma was present the results were somewhat different. The results of predictions for alpha radiation, at the 47 current nitrate and nitrite concentrations in the SRS tanks indicated that all the SRS predictions were higher (up to 30%) than the Hanford predictions and thus more conservative. For beta/gamma radiation the predictions for both models agreed to {+-}10% for 18 of the combinations, the Hanford model predicted higher values (11 up to 17%) for 25 of the concentrations considered, and the SRS model predicted higher G values for the remaining two combinations (12 and 17%). For the four SRS tanks, where we compared measured G values to those predicted by the two differen

Crawford, C; Ned Bibler, N

2009-04-15

144

Carbon Monoxide Levels in Bathrooms Using Hot Water Boilers  

Microsoft Academic Search

The purpose of the present study was to measure carbon monoxide (CO) levels during the operation of hot water boilers that use liquefied petroleum gas or natural gas, which are widely used in Turkey. In addition, it was intended to determine how much owners of these boil ers knew about their use and about CO poisoning. CO levels were measured

Ö. Faruk Tekba?; Songül Acar Vaizoglu; E. Didem Evci; Bekir Yüceer; Ça?atay Güler

2001-01-01

145

Carbon Monoxide Levels in Bathrooms Using Hot Water Boilers  

Microsoft Academic Search

The purpose of the present study was to measure carbon monoxide (CO) levels during the operation of hot water boilers that use liquefied petroleum gas or natural gas, which are widely used in Turkey. In addition, it was intended to determine how much owners of these boilers knew about their use and about CO poisoning. CO levels were measured in

E. Didem Evci; Bekir Yüceer

2001-01-01

146

January 1983 water levels, and data related to water-level changes, western and south-central Kansas  

USGS Publications Warehouse

Water-level measurements were made, mostly in January 1983, in about 1,540 wells in western and south-central Kansas. The measurements were made in mid-winter when pumping was minimal and water levels had recovered, for the most part, from the effects of pumping during the previous irrigation season. Annual hydrologic data are provided for relating water-level changes from a ' base-reference year ' (predevelopment year), a year of abnormally high rainfall and minimum pumpage (1966 or 1974) and each of seen consecutive years of measurement (1977-83). The ' base-reference year ' is designated as 1940 for the southwestern area, 1944 for the south-central area, and 1950 for the northwestern and west-central areas. Water levels for the ' base-reference year ' are established by measurements made during that year and by interpretation of maps showing water-level altitudes. Data also are provided for relating the average annual water-level changes, saturated thicknesses of the deposits, and percentage changes in saturated thicknesses. (USGS)

Pabst, Marilyn E.

1983-01-01

147

Methodology for predicting cooling water effects on fish  

SciTech Connect

The mathematical model presented here predicts the long-term effects of once-through cooling water systems on local fish populations. The fish life cycle model simulates different life stages of fish by using appropriate expressions representing growth and mortality rates. The heart of the developed modeling approach is the prediction of plant-caused reduction in total fish population by estimating recruitment to adult population with and without entrainment of ichthyoplankton and impingement of small fish. The model was applied to a local fish species, gilthead (Aparus aurata), for the case of a proposed power plant in the Aegean region of Turkey. The simulations indicate that entrainment and impingement may lead to a population reduction of about 2% to 8% in the long run. In many cases, an impact of this size can be considered rather unimportant. In the case of sensitive and ecologically values species facing extinction, however, necessary precautions should be taken to minimize or totally avoid such an impact.

Cakiroglu, C. [Turkish Electricity Generation and Transmission Corp., Ankara (Turkey); Yurteri, C. [Middle East Tech. Univ., Ankara (Turkey). Environmental Engineering Dept.

1998-07-01

148

Analysis for water level data for Everglades National Park, Florida  

USGS Publications Warehouse

Stage-duration curves were developed for five gaging stations in Everglades National Park, Florida. Four of the five curves show similar characteristics with an increase in the slope when the water level is below land surface. Monthly stage-duration curves, developed for one of the stations, reflect the seasonal trends of the water level. Recession curves were prepared for the same five stations. These curves represent the average water-level decline during periods of little or no rainfall. They show the decline in level at the end of 10, 20, and 60 days for any given initial stage. A family of curves was also prepared to give the recession from various initial stages for any period up to 60 days.

Buchanan, T. J.; Hartwell, J. H.

1972-01-01

149

Simulating time-varying cave flow and water levels using the Storm Water Management Model  

Microsoft Academic Search

The Storm Water Management Model (SWMM) is an Environmental Protection Agency code used to estimate runoff through storm water drainage systems that include channels, pipes, and manholes with storage. SWMM was applied to simulate flow and water level changes with time for a part of Stephens Gap Cave in Jackson County, Alabama. The goal of the simulation was to estimate

C. Warren Campbell; Sean M Sullivan

2002-01-01

150

Raw Water Bromide: Levels and Relationship to Distribution of Trihalomethanes in Finished Drinking Water.  

National Technical Information Service (NTIS)

A study was conducted to examine the effect of raw water bromide on the formation and distribution of trihalomethanes (THMS) in finished drinking water. Twenty major water supplies in East Tennessee were selected for their significant levels of bromine-co...

R. A. Minear C. M. Morrow

1983-01-01

151

Snow Water Equivalent Predictions for Hydrologic Model Input and Simulation  

NASA Astrophysics Data System (ADS)

A multiple regression equation was developed to describe temporal and spatial variability of daily snow water equivalent (SWE) in Lake Tahoe's Incline Creek watershed. SWE maps of the basin are needed for parameterization of the physically-based Alpine Hydrochemical Model (AHM) to simulate basin hydrology and solute transport. SWE maps allow for calculation of snow covered area, snowfall, and potential snowmelt needed for AHM input. SWE data collected during 2002's peak snow accumulation were used in conjunction with data from three local SNOTEL stations to calibrate the regression equation. Calibration was conducted during a dry and average water year using the sum of least squares. The multiple-regression is dependent on elevation, aspect, slope, vegetation density and solar radiation and is normalized by the average SWE measured at the three SNOTEL sites. Basin-wide computations were done at 30 m resolution in ArcView to generate daily SWE maps. Normalized error was added to predictions from the regression equation to mimic the variability in the observed data. Verification was performed at the three SNOTEL sites for a wet year and another average year. Stream response is highly dependent on SWE distribution and associated melt rates such that hydrologic model results allow evaluation of the SWE interpolation technique.

Carroll, R. W.

2003-12-01

152

Predicting FCAT Reading Scores Using the Reading-Level Indicator  

ERIC Educational Resources Information Center

|Multiple regression analysis indicates that the Reading-Level Indicator, a paper-and-pencil test, is a moderately strong predictor for the high-stakes standardized test, the Florida Comprehensive Achievement Test in Reading. Classroom teachers can administer the inexpensive Reading-Level Indicator in a short period of time and use the results as…

Stanley, Nile; Stanley, Laurel

2011-01-01

153

Prediction of underwater sound levels from rain and wind.  

PubMed

Wind and rain generated ambient sound from the ocean surface represents the background baseline of ocean noise. Understanding these ambient sounds under different conditions will facilitate other scientific studies. For example, measurement of the processes producing the sound, assessment of sonar performance, and helping to understand the influence of anthropogenic generated noise on marine mammals. About 90 buoy-months of ocean ambient sound data have been collected using Acoustic Rain Gauges in different open-ocean locations in the Tropical Pacific Ocean. Distinct ambient sound spectra for various rainfall rates and wind speeds are identified through a series of discrimination processes. Five divisions of the sound spectra associated with different sound generating mechanisms can be predicted using wind speed and rainfall rate as input variables. The ambient sound data collected from the Intertropical Convergence Zone are used to construct the prediction algorithms, and are tested on the data from the Western Pacific Warm Pool. This physically based semi-empirical model predicts the ambient sound spectra (0.5-50 kHz) at rainfall rates from 2-200 mm/h and wind speeds from 2 to 14 m/s. PMID:16018459

Ma, Barry B; Nystuen, Jeffrey A; Lien, Ren-Chieh

2005-06-01

154

Methods for predicting the optimum and the range of soil water contents for tillage based on the water retention curve  

Microsoft Academic Search

Information is needed on the range of soil water contents for tillage. The objective of the work was to develop methods for the prediction of the soil water contents at which tillage may be done satisfactorily. Three water contents are considered: the lower (dry) limit, the optimum water content, and the upper (wet) limit. This paper makes a synthesis of

A. R Dexter; N. R. A Bird

2001-01-01

155

Regional and State Level Water Scarcity Report: Northeast United States  

NASA Astrophysics Data System (ADS)

There are an abundance of large-scale, coarse resolution global water scarcity studies, but the existing literature fails to address regional and state specific scarcity measures. Moreover, while environmental water requirements are an integral factor in the development and implementation of sustainable water management practices, only recently has this notion been introduced to water scarcity research. In this paper, we argue that developing a preliminary measure of water scarcity, at the regional and state levels, will allow for more informed policy development. The goal of this study is to generate a more comprehensive understanding of water scarcity in the Northeast, by gathering fine scale data, applying a consistent methodology to the calculation of a scarcity index, and analyzing the results to see relative trends in spatio-temporal water scarcity. Public supply, irrigation, rural, industrial and thermo-power withdrawals have been compiled from USGS state water use publications from 1950 to 1985. Using the WBMplus water model runoff data, state specific in-stream environmental water requirements were calculated using the accepted hydro-ecological methodology. Water scarcity was then calculated as a ratio of water withdrawals to total available water minus environmental flow requirements for the system. In so doing, this study generates a spatially explicit and temporally varying water scarcity indicator (WSI) for the Northeastern United States between 1950 and 2000 at the regional and state levels at a five-year time interval. Calculation of a spatial and temporal water scarcity indicator enabled us to identify regions and specific states that were: slightly exploited (WSI < 0.3), moderately exploited (0.31.0). The minimum environmental water requirements to maintain in-stream aquatic and riparian ecosystems for the Northeastern states ranged between 27.5 to 36.3 percent of the mean annual runoff within Vermont and Maryland, respectively. The regional WSI values ranged between 0.199 in 1950 and 0.512 in 1995, indicating increasing water scarcity over time as population and employment growth has placed greater demands on water resources. Additionally, our study revealed that in 1980, Massachusetts, Pennsylvania and New Jersey scarcity levels were 0.733, 0.790 and 0.857, respectively. Although the Northeastern United States is commonly perceived as a water rich region, moderate to heavily exploited levels of water stress were observed over the time period when a finer spatial scale is utilized. Water scarcity indicator values were disaggregated by state for each time period and illustrated using a series of maps. Additional descriptive statistics were used to elucidate the differences in water scarcity between states over time.

Nicoletti, C. K.; Lopez-Morales, C. A.; Hoover, J. H.; Voigt, B. G.; Vorosmarty, C. J.; Mohammed, I. N.

2010-12-01

156

Surveying Ground Water Level Using Remote Sensing: An Example over the Seco and Hondo Creek Watershed in Texas  

Microsoft Academic Search

The Normalized Difference Vegetation Index (NDVI) derived from satellite data has been applied to various vegetation studies. The objective of this study was to assess the feasibility of using the NDVI response to plant water content to predict ground water level over a watershed located in the Edwards Aquifer of Texas, USA. Results showed that the precipitation data collected inside

Pei-yu Chen; Jeffrey G. Arnold; Raghavan Srinivasan; Martin Volk; Peter M. Allen

2006-01-01

157

Gastric cancer mortality and nitrate levels in Wisconsin drinking water.  

PubMed

The association between nitrate levels in public and private sources of drinking water and gastric cancer mortality in Wisconsin was investigated in a case-control study. All gastric cancer deaths of Wisconsin residents from 1982 through 1985 were compared with deaths from other causes (controls), and nitrate levels in the home drinking water of these residents were determined. Nitrate measures for public sources were obtained from historic nitrate data from municipal sources that existed in 1970. Nitrate measures for private water sources were obtained by testing the wells individually at the existing residences. Controls were matched individually to gastric cancer cases with respect to sex, year of birth, year of death, Wisconsin birth, and Wisconsin residency at the time of death. Matched-pair analyses were performed on the paired data, and the following levels of nitrate-nitrogen exposure were used as indicators of exposure: 0.5, 2.5, 5.0, and 10.0 mg/l. Matched-pair analysis was also performed for which private water supply constituted exposure. Odds ratios and 95% confidence intervals were, respectively, 0.92 (0.75, 1.12); 0.97 (0.74, 1.35); 0.86 (0.69, 1.08); 1.50 (0.12, 18.25); and 1.09 (0.82, 1.47) for exposure to private well-water sources. These results did not indicate an increased risk of gastric cancer at any level. PMID:1497383

Rademacher, J J; Young, T B; Kanarek, M S

158

Wii mote as hydrological sensor: observation of water level fluctuations  

NASA Astrophysics Data System (ADS)

The input device of the Nintendo Wii, the Wii-mote offers scientist a multitude of cheap, high quality sensors; ideal for proof of concept testing. For a specific application, i.e. the water level fluctuation in a floating evaporation pan the Wii-mote was tested as the observing device. It is shown that the controller can observe movements with high enough temporal and spatial resolution of up to 4 infrared LED’s to describe water level movements. Floating pans positioned in lakes and reservoirs better represent open water evaporation than evaporation pans installed on land. On the other hand performing water level measurements in a floating pan is more complicated due to movement of the pan and wave activities in the pan. The Wii-mote was mounted on the side of a standard class A-pan and a float was placed in the middle of the pan, with 4 LED’s on top moving along a fixed bar. The information that the Wii-mote wirelessly sends by blue tooth was captured on a laptop. With a MATLAB routine this data was converted into movement of the LED’s relatively to the controller. The observations show that wave activities are nicely captured with a typical spatial resolution smaller than 0.1 mm in our set-up and a temporal resolution of maximum 100 Hz. A frequency domain filter was applied to the observed datasets to obtain average water levels. In our laboratory setting the pan was placed in a large basin with a wave generator. A constant, but small, rate of water was added to the evaporation pan. The average pan levels from the filtered datasets showed systematically lower levels compared to the level without any wave activities. This is a typical effect of waves that occur in shallow basins. However, the added water with rates up to 5 mm/hour were clearly recognized in the filtered datasets which indicates that the Wii-mote is very well capable as a sensor for water level observations.

Luxemburg, W.; Hut, R.; Weijs, S.; Hegnauer, M.

2009-12-01

159

Water Quality and pH Levels in Aquatic Ecosystems  

NSDL National Science Digital Library

In this fun and in depth hands-on experiment, learners test various liquid samples (distilled water, lemon juice, vinegar, and baking soda mixed with water) to determine their pH levels and identify each sample as either acid, base or neutral chemical. Then, over the course of several weeks, learners perform a number of tests and observe the affects of pH level on plants. The wrap up section of this activity discusses acid rain and its dramatic impact on aquatic animals, and tips for going further.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

160

Smoking cessation: social comparison level predicts success for adult smokers.  

PubMed

The affiliation preferences of 151 adult heavy smokers who joined smoking cessation groups were assessed at the 1st group session and were then used to predict their smoking status 6 and 12 months later. Those who preferred to be in groups with other smokers who were having relatively little trouble quitting were more likely to be successful than were those who preferred others who were having more difficulty quitting. This prospective effect was mediated by psychological distancing from the image of the typical smoker: Preference for others who were doing well was associated with a decrease in perceived similarity to the typical smoker, which, in turn, was associated with successful cessation. Implications of these findings for cessation groups and social comparison theory are discussed. PMID:16287409

Gerrard, Meg; Gibbons, Frederick X; Lane, David J; Stock, Michelle L

2005-11-01

161

Predicting potential COBOL performance on low level machine architectures  

Microsoft Academic Search

As a COBOL host, a computer architecture should efficiently execute those language constructs that are most frequently used in actual programs. However, when the language's control and data structures are at a far higher level than the control and data structures of the underlying machine, the compiler designer is faced with a large number of potential choices for mapping these

Jerome A. Otto

1985-01-01

162

Monitoring of Soil Moisture and Groundwater Level Using Ultrasonic Waves to Predict Slope Failures  

NASA Astrophysics Data System (ADS)

Field monitoring of soil moisture and groundwater levels is important to predict slope failures due to heavy rainfall. We have investigated a novel monitoring method using ultrasonic waves. The detector is composed of an ultrasonic transducer and a brass pipe whose lower end is inserted vertically into the ground. Ultrasonic waves generated by the transducer at the upper end of the pipe travel through it underground, and are reflected from the soil’s surface at the bottom of the pipe. The soil’s moisture is monitored by the intensity of the reflected ultrasonic waves and the groundwater level is monitored by the propagation time of the same waves. Indoor experiments were carried out using an artificial rainfall simulator and a soil tank. Shigaraki soil and Toyoura sand were used as soil samples in the experiments. The intensity of the reflected waves increased with the soil’s water content and changed dramatically depending on whether the soil was fully dry, wet, or fully saturated. The propagation time decreased as the groundwater level rose. This method has advantages in that the detector can easily be installed on the ground surface and can simultaneously monitor both the soil moisture and groundwater level.

Tanaka, Katsuhiko; Suda, Takefumi; Hirai, Kazuhiro; Sako, Kazunari; Fukagawa, Ryoichi

2009-09-01

163

Using silicates to lower lead levels in drinking water  

SciTech Connect

York is a small resort town on the coast of Maine, near the New Hampshire border. The town's population of 5,000 usually doubles during the summer tourist season. Like many small water systems in New England, its soft, moderately alkaline water corrodes its unlined, cast-iron pipe distribution system, picking up significant quantities of iron along the way. Customers served by these lines have complained about the red water. York Water District officials hoped that a new 4-mgd treatment facility brought into service in spring 1990 would alleviate the red water problems, but they were also considering ways to address the requirements of the Lead and Copper Rule from the EPA promulgated in 1991. With the assistance of their consulting engineering firm, York Water District officials evaluated treatment strategies and decided against using polyphosphates to control lead and copper because of their ability to complex with the metals, possibly causing an increase in concentration. The officials eventually chose sodium silicates to lower the iron, lead, and copper levels in the system. Several utilities in Maine had reported using sodium silicate as a common strategy for red water problems. In addition, sodium silicate was favored because it reacts with metal for form a barrier to corrosion. York Water District, with assistance from its consultant, designed an 18-month program to add sodium silicates to its system, track metal concentrations, and monitor red water complaints. The district prepared a report for the EPA, covering data collected over the first 12 months of the program -- essentially calendar year 1991. According to Michael R. Schock, research chemist with the EPA's Drinking Water Research Division in Cincinnati, the agency is anxious to obtain as much quantitative information as possible on using sodium silicate for pH and/or corrosion control. This article describes the monitoring system, water treatment and study results.

Not Available

1994-09-01

164

Prediction of projectile ricochet behavior after water impact.  

PubMed

Although not very common, forensic investigation related to projectile ricochet on water can be required when undesirable collateral damage occurs. Predicting the ricochet behavior of a projectile is challenging owing to numerous parameters involved: impact velocity, incident angle, projectile stability, angular velocity, etc. Ricochet characteristics of different projectiles (K50 BMG, 0.5-cal Ball M2, 0.5-cal AP-T C44, 7.62-mm Ball C21, and 5.56-mm Ball C77) were studied in a pool. The results are presented to assess projectile velocity after ricochet, ricochet angle, and projectile azimuth angle based on impact velocity or incident angle for each projectile type. The azimuth ranges show the highest variability at low postricochet velocity. The critical ricochet angles were ranging from 15 to 30°. The average ricochet angles for all projectiles were pretty close for all projectiles at 2.5 and 10° incident angles for the range of velocities studied. PMID:22536929

Baillargeon, Yves; Bergeron, Guy

2012-04-26

165

Low-level measurements of tritium in water.  

PubMed

Using a liquid scintillation counter, an experimental procedure for measuring low-level activity concentrations of tritium in environmental water has been developed by our laboratory, using the electrolytic tritium enrichment. Additionally, some quality tests were applied in order to assure the goodness of the method. Well-known water samples collected in the Tagus River (West of Spain) and the Danube River (Bulgaria), both affected by nuclear plant releases, were analysed and results were compared to previous data. The analytical procedure was applied to drinking water samples from the public water supply of Seville and mineral waters from different springs in Spain in order to characterize its origin. Due to the very low levels of tritium in the analysed samples, some results were reported as lower than the minimum detectable activity concentration (MDA). However, the count rate of these measurements was over the background count rate of LS counter in all the cases. For that reason, an exhaustive discussion about the meaning of the MDA, using an experimental essay, was made in order to establish a rigorous criterion that leads to a reliable value in the case of low-level measurements. PMID:15177365

Villa, M; Manjón, G

166

Analysis of water level variations in Brazilian basins using GRACE  

NASA Astrophysics Data System (ADS)

A comparison between daily in-situ water level time series measured at ground-based hydrometric stations (HS - 1,899 stations located in twelve Brazilian basins) of the Agência Nacional de Águas (ANA) with vertically-integrated water height anomaly deduced from the Gravity Recovery and Climate Experiment (GRACE) geoid is carried out in Brazil. The equivalent water height (EWH) of 10-day intervals of GRACE models were computed by GRGS/CNES. It is a 6-year analysis (July-2002 to May-2008). The coefficient of determination is computed between the ANA water level and GRACE EWH. Values higher than 0.6 were detected in the following basins: Amazon, north of Paraguay, Tocantins-Araguaia, Western North-East Atlantic and north of the Parnaíba. In the Uruguay (Pampas region) and the west of São Francisco basins, the coefficient of determination is around 0.5 and 0.6. These results were adjusted with a linear transfer function and two second degree polynomials (flood and ebb period) between GRACE EWH and ANA water level. The behavior of these two polynomials is related to the phase difference of the two time series and yielded four different types of responses. This paper shows seven ANA stations that represent these responses and relates them with their hydro-geological domain.

Matos, A.; Blitzkow, D.; Almeida, F.; Costa, S.; Campos, I.; Barbosa, A.

2012-01-01

167

Measurement for Water Content in Oil-Water Two Phase Flow Based on Novel Hybrid Intelligent Prediction Model  

Microsoft Academic Search

Some parameters affecting the measurement of water content in oil\\/water two-phase flow are detected using multi-sensor technology, and a novel hybrid intelligent prediction model is proposed to improve measuring precision of water content. Some advanced information processing technologies, such as neural networks optimized by hybrid genetic algorithm, combined method for decisions of multiple sub-modules, are introduced in this intelligent prediction

Zhang Dongzhi; Xia Bokai; Fu Tao

2007-01-01

168

Concentration trends and water-level fluctuations at underground storage tank sites  

Microsoft Academic Search

Concentration trends of monitor wells utilized in monitored natural attenuation at petroleum underground storage tank sites\\u000a can be used to predict achievement of regulatory standards if the data approximate a first-order decline trend. However, declining\\u000a concentration trends often display seasonal and other fluctuations that complicate trend interpretation. Seasonal correlations\\u000a between concentration and water-level elevation, including in-phase and inverse relationships, constitute

Alan E. KehewPatrick; Patrick M. Lynch

2011-01-01

169

Characterization of Inter Digital capacitor for water level sensor  

Microsoft Academic Search

This paper discussed about design and characterization of the Inter Digital capacitor. The main objective is to study the effects of width and spacing of the capacitor electrode on capacitance value. Water levels sensors are studied by using Inter Digital Capacitor (IDC) technique on Printed Circuit Board (PCB). IDC technique is used to make the capacitance measurement of the solution

A. Manut; A. S. Zoolfakar; N. A. Muhammad; M. Zolkapli

2011-01-01

170

CAN FLUORIDATION AFFECT WATER LEAD LEVELS AND LEAD NEUROTOXICITY?  

EPA Science Inventory

Recent reports have attempted to show that certain approaches to fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of nexafluo...

171

A Receding Horizon Controller for the Steam Generator Water Level  

Microsoft Academic Search

In this work, the receding horizon control method was used to control the water level of nuclear steam generators and applied to two linear models and also a nonlinear model of steam generators. A receding horizon control method is to solve an optimization problem for finite future steps at current time and to implement the first optimal control input as

Man Gyun Na; Yoon Joon Lee

2003-01-01

172

Radioactive Levels in Taihu and Water Bodies of Suzhou.  

National Technical Information Service (NTIS)

The radioactive levels in Taihu and water bodies of Suzhou, southern China, were investigated in 1983. The results of the investigation were compared with that of 1973. In addition, the authors investigated a suspected radioactive pollutant-ash of coal po...

Z. Zhang R. Fu N. Zhu H. Wang Q. Hu

1988-01-01

173

Variation of Great Lakes water levels derived from Geosat altimetry  

Microsoft Academic Search

A technique for using satellite radar altimetry data to estimate the temporal variation of the water level in moderate to large lakes and enclosed seas is described. Great Lakes data from the first 2 years of the U. S. Navy's Geosat Exact Repeat Mission (November 1986 to November 1988), for which there is an improved orbit, are used to demonstrate

Charles S. Morris; Stephen K. Gill

1994-01-01

174

Variation of Great Lakes water levels derived from Geosat altimetry  

Microsoft Academic Search

A technique for using satellite radar altimetry data to estimate the temporal variation of the water level in moderate to large lakes and enclosed seas is described. Great Lakes data from the first 2 years of the U.S. Navy's Geosat Exact Repeat Mission (November 1986 to November 1988), for which there is an improved orbit, are used to demonstrate the

Charles S. Morris; Stephen K. Gill

1994-01-01

175

Predicting Group-Level Outcome Variables from Variables Measured at the Individual Level: A Latent Variable Multilevel Model  

ERIC Educational Resources Information Center

In multilevel modeling, one often distinguishes between macro-micro and micro-macro situations. In a macro-micro multilevel situation, a dependent variable measured at the lower level is predicted or explained by variables measured at that lower or a higher level. In a micro-macro multilevel situation, a dependent variable defined at the higher…

Croon, Marcel A.; van Veldhoven, Marc J. P. M.

2007-01-01

176

Assessing Risk in Operational Decisions Using Great Lakes Probabilistic Water Level Forecasts  

PubMed

/ A method adapted from the National Weather Service's Extended Streamflow Prediction technique is applied retrospectively to three Great Lakes case studies to show how risk assessment using probabilistic monthly water level forecasts could have contributed to the decision-mak-ing process. The first case study examines the 1985 International Joint Commission (IJC) decision to store water in Lake Superior to reduce high levels on the downstream lakes. Probabilistic forecasts are generated for Lake Superior and Lakes Michigan-Huron and used with riparian inundation value functions to assess the relative impacts of the IJC's decision on riparian interests for both lakes. The second case study evaluates the risk of flooding at Milwaukee, Wisconsin, and the need to implement flood-control projects if Lake Michigan levels were to continue to rise above the October 1986 record. The third case study quantifies the risks of impaired municipal water works operation during the 1964-1965 period of extreme low water levels on Lakes Huron, St. Clair, Erie, and Ontario. Further refinements and other potential applications of the probabilistic forecast technique are discussed.KEY WORDS: Great Lakes; Water levels; Forecasting; Risk; Decision making PMID:8939784

LEE; CLITES; KEILLOR

1997-01-01

177

Liquid-vapor equilibrium isotopic fractionation of water: How well can classical water models predict it?  

Microsoft Academic Search

The liquid-vapor equilibrium isotopic fractionation of water is determined by molecular-based simulation, via Gibbs ensemble Monte Carlo and isothermal-isochoric molecular dynamics involving two radically different but realistic models, the extended simple point charge, and the Gaussian charge polarizable models. The predicted temperature dependence of the liquid-vapor equilibrium isotopic fractionation factors for H218O\\/H216O, H217O\\/H216O, and 2H1H16O\\/1H216O are compared against the most

Ariel A. Chialvo; Juske Horita

2009-01-01

178

Affordable Drinking Water Treatment for Public Water Systems Contaminated by Excess Levels of Natural Fluoride.  

National Technical Information Service (NTIS)

The report explores affordable treatments for public drinking water systems that have been contaminated by excess levels of naturally occurring fluoride. The report includes discussion of fluoride occurrences in groundwater, remediation techniques associa...

C. Mastropaolo

1991-01-01

179

Exploring predictions of safe operating spaces for human water use  

NASA Astrophysics Data System (ADS)

In the Nature article 'A safe operating space for humanity', Rockström et al. (2009) introduce the idea of a safe space for human activities that will not push the planet out of the 'Holocene state'. Rockström et al. have identified nine earth-system processes and associated thresholds which, if crossed, are expected to generate unacceptable environmental change. Rockström et al. (2009) focus on the scientific prediction of these thresholds. Concerning the use of these boundaries for public policy, these authors limit their efforts to concluding that the evidence so far suggests that, as long as the thresholds are not crossed, humanity has the freedom to pursue long-term social and economic development. The approach advocated by Rockström et al. (2009) is plagued by two related problems: uncertainty and dynamic complexity (Molden, 2009; Brewer, 2009). The latter problem addresses the reductionist approach of Rockström et al and argues, in opposition, that the limits on each of the nine earth-system processes are co-depended and thus the safe operating space constitutes a single multi-dimensional space that can only be identified holistically. The first problem is that our current scientific knowledge and understanding of the earth system is incomplete and partly contested. A majority of the authors reacting on the global limit concept do however emphasize their relevance as "targets for policy makers". However, the two problems imply that the establishment of predicted global limits as a substantive base for public policy is meaningless. Still, the presence of scientific uncertainty and dynamic complexity and thus the omnipresence of unpredictability need not be used as an excuse to ignore the importance of a substantive grounding of these policies. In this paper, we argue and show how despite dynamic complexity and irreducible uncertainty, policies can be designed, tested, and shown to be effective in reaching broad social goals related to social and economic development. To this end, we utilize ANEMI (Davies and Simonovic, 2011), a dynamic impact assessment model of the planetary fresh water cycle and related systems (e.g. economy, land use, population, and climate). We assess the dynamics of this model over a broad range of different uncertainties; we identify combinations of uncertainties that produce dynamics that threaten the flourishing of humanity, and use these insights to develop public policies that can counteract these undesirable dynamics.

Kwakkel, J. H.; Timmermans, J. S.

2012-04-01

180

Prediction of water quality index (WQI) based on artificial neural network (ANN)  

Microsoft Academic Search

This paper investigates the effectiveness of artificial neural network models for predicting the water quality index for rivers in Malaysia. The network was trained with reference to seven major parameters for the determination of the water pollutant index, water quality index and water quality class, for Malaysian rivers in Pahang and Selangor. The data collected comprises of data for the

Lee Yoot Khuan; Noraliza Hamzah; Rozita Jailani

2002-01-01

181

Relationships between levels of heterotrophic bacteria and water quality parameters in a drinking water distribution system  

Microsoft Academic Search

Conventional plating methods were used to quantify heterotrophic bacteria from a drinking water distribution system. Three media, plate count agar (PCA), R2A agar and sheep blood agar (TSA-SB) were used to determine heterotrophic plate count (HPC) levels. Grab samples were collected weekly during the summer and autumn of 1997 at four locations in a municipal water distribution system. The four

J. T Carter; E. W Rice; S. G Buchberger; Y Lee

2000-01-01

182

The Water Resources Division water level recorder rental program; history and operation  

USGS Publications Warehouse

The U.S. Geological Survey introduced a new water level recorder in the early 1960 's to automate computation of streamflow records. At the same time it developed a rental program as a means of providing the recorders to field offices. This report documents the experience gained over the past 20 years and offers suggestions for operation of a rental program in the future, as preparation is made to introduce a third generation of water level recorders. (USGS)

Jeffers, S. R.; Wagner, C. R.

1984-01-01

183

Estimation of the uncertainty in water level forecasts at ungauged locations using Quantile Regression  

NASA Astrophysics Data System (ADS)

Water level predictions in rivers are used by operational managers to make water management decisions. Such decisions can concern water routing in times of drought, operation of weirs, and actions for flood protection, such as evacuation. Understanding the uncertainty in the predictions can help managers make better-informed decisions. Conditional Quantile Regression is a method that can be used to determine the uncertainty in forecasted water levels by providing an estimate of the probability density function of the error in the prediction conditional on the forecasted water level. To derive this relationship, a series of forecasts and errors in the forecasts (residuals) are required. Thus, conditional quantile regressions can be derived for locations where both observations and forecasts are available. However, 1D-hydraulic models that are used for operational forecasting produce forecasts at intermediate points where no measurements are available but for which predictive uncertainty estimates are also desired for decision making. The objective of our study is to test if interpolation methods can be used to adequately estimate conditional quantile regressions at these in-between locations. For this purpose, five years of hindcasts were used at seven stations along the IJssel River in the Netherlands. Residuals in water level hindcasts were interpolated at the five in-between lying stations. The interpolation was based solely on distance and the interpolated residuals were compared to the measured residuals at stations at the in-between locations. The resulting interpolated residuals estimated the measured residuals well, especially for longer lead times. Quantile regression was then carried out using the series of forecasts and interpolated residuals at the in-between stations. The interpolated quantile regressions were compared with regressions calibrated using the actual residuals at the in-between stations. Results show that even a simple interpolation based solely on distance provides good quantile estimates, making this method a promising option for estimating uncertainty in water level forecasts at locations without measurements. Practical considerations for implementing the method operationally will be discussed.

Roscoe, K. L.; Weerts, A. H.

2012-04-01

184

Rising water levels and the future of southeastern Louisiana swamp forests  

USGS Publications Warehouse

An important factor contributing to the deterioration of wetland forests in Louisiana is increasing water levels resulting from eustatic sea-level rise and subsidence. Analyses of long-term water level records from the Barataria and Verret watersheds in southeastern Louisiana indicate an apparent sea level rise of about 1-m per century, mainly the result of subsidence. Permanent study plots were established in cypress-tupelo stands in these two watersheds. The tree, water level, and subsidence data collected in these plots were entered into the U.S. Fish and Wildlife Servicea??s FORFLO bottomland hardwood succession model to determine the long-term effects of rising water levels on forest structure. Analyses were made of 50a??100 years for a cypress-tupelo swamp site in each basin and a bottomland hardwood ridge in the Verret watershed. As flooding increased, less flood tolerant species were replaced by cypress-tupelo within 50 years. As flooding continued, the sites start to become nonforested. From the test analyses, the FORFLO model seems to be an excellent tool for predicting long-term changes in the swamp habitat of south Louisiana.

Conner, W.H.; Brody, M.

1989-01-01

185

Unraveling the climatic causes of past lake level change using lake energy and water balance models  

NASA Astrophysics Data System (ADS)

Lake level records provide a rich resource of information about past variations in surface water, a resource likely to experience significant impacts under future climate change. The water balance of a lake is controlled by a variety of climate variables, including precipitation, radiation, humidity, and wind speed, and it can be difficult to pinpoint the exact climatic causes of past lake level fluctuations. This understanding is crucial, however, for predicting whether surface water resources will diminish in the future. In this research, we use output from a coupled atmosphere-ocean general circulation model to force lake energy and water balance models over East Asia and Arid Central Asia to test hypotheses about the causes of lake level variations during the Holocene and Last Glacial Maximum. We find that changes in evaporation tend to work in concert with precipitation changes to maximize lake level fluctuations. This occurs because high levels of precipitation are associated with increased cloudiness and humidity and decreased shortwave radiation, which all lead to decreased lake evaporation. There is also a significant effect of changes in winter insolation on the annual duration of lake ice cover and lake evaporation. These findings help to explain some of the differences in lake level observed between monsoonal Asia and Arid Central Asia and can be generalized to other parts of the globe.

Morrill, C.; Li, Y.

2009-12-01

186

Reservoir Water Level Impacts on Recreation, Property, and Nonuser Values  

NASA Astrophysics Data System (ADS)

Wise interbasin management of Southeastern U.S. water resources is important for future development. AlabamaCoosa-Tallapoosa and Apalachicola-Flint-Chattahoochee River basins' water usage has evolved from power generation to multiple uses. Recreation and housing have become increasingly valuable components. Changing use patterns imply changing resource values. This study focused on six Alabama reservoirs, using contingent valuation questions in on-site, telephone, and mail surveys to estimate impacts on lakefront property values, recreational expenditures, and preservation values for scenarios of permanent changes to reservoir water quantity. As summer full-pool duration decreased, lakefront property value decreased, and as duration increased, property values increased, but at a lesser rate. Similar findings occurred for winter drawdown alternatives. Permanent one-foot reductions in summer full-pool water levels resulted in a 4 to 15 percent decrease in lakefront property values. Recreational expenditures decreased 4 to 30 percent for each one-foot lowering of reservoir water levels. Current nonusers of the six reservoirs showed strong preferences for protecting study reservoirs with willingness to pay values of 47 per household or approximately 29 million for the entire six-reservoir watershed basin area. Resource management based on historic use patterns may be inappropriate and more frequent and comprehensive valuation of reservoir resources is needed.

Hanson, Terrill R.; Upton Hatch, Luther; Clonts, Howard C.

2002-08-01

187

Predicted transport of pyrethroid insecticides from an urban landscape to surface water.  

PubMed

The authors developed a simple screening-level model of exposure of aquatic species to pyrethroid insecticides for the lower American River watershed (California, USA). The model incorporated both empirically derived washoff functions based on existing, small-scale precipitation simulations and empirical data on pyrethroid insecticide use and watershed properties for Sacramento County, California, USA. The authors calibrated the model to in-stream monitoring data and used it to predict daily river pyrethroid concentration from 1995 through 2010. The model predicted a marked increase in pyrethroid toxic units starting in 2000, coincident with an observed watershed-wide increase in pyrethroid use. After 2000, approximately 70% of the predicted total toxic unit exposure in the watershed was associated with the pyrethroids bifenthrin and cyfluthrin. Pyrethroid applications for aboveground structural pest control on the basis of suspension concentrate categorized product formulations accounted for greater than 97% of the predicted total toxic unit exposure. Projected application of mitigation strategies, such as curtailment of structural perimeter band and barrier treatments as recently adopted by the California Department of Pesticide Regulation, reduced predicted total toxic unit exposure by 84%. The model also predicted that similar reductions in surface-water concentrations of pyrethroids could be achieved through a switch from suspension concentrate-categorized products to emulsifiable concentrate-categorized products without restrictions on current-use practice. Even with these mitigation actions, the predicted concentration of some pyrethroids would continue to exceed chronic aquatic life criteria. Environ Toxicol Chem 2013;32:2469-2477. © 2013 SETAC. PMID:24115122

Jorgenson, Brant; Fleishman, Erica; Macneale, Kate H; Schlenk, Daniel; Scholz, Nathaniel L; Spromberg, Julann A; Werner, Inge; Weston, Donald P; Xiao, Qingfu; Young, Thomas M; Zhang, Minghua

2013-09-20

188

Remotely mapping river water quality using multivariate regression with prediction validation.  

SciTech Connect

Remote spectral sensing offers an attractive means of mapping river water quality over wide spatial regions. While previous research has focused on development of spectral indices and models to predict river water quality based on remote images, little attention has been paid to subsequent validation of these predictions. To address this oversight, we describe a retrospective analysis of remote, multispectral Compact Airborne Spectrographic Imager (CASI) images of the Ohio River and its Licking River and Little Miami River tributaries. In conjunction with the CASI acquisitions, ground truth measurements of chlorophyll-a concentration and turbidity were made for a small set of locations in the Ohio River. Partial least squares regression models relating the remote river images to ground truth measurements of chlorophyll-a concentration and turbidity for the Ohio River were developed. Employing these multivariate models, chlorophyll-a concentrations and turbidity levels were predicted in river pixels lacking ground truth measurements, generating detailed estimated water quality maps. An important but often neglected step in the regression process is to validate prediction results using a spectral residual statistic. For both the chlorophyll-a and turbidity regression models, a spectral residual value was calculated for each river pixel and compared to the associated statistical confidence limit for the model. These spectral residual statistic results revealed that while the chlorophyll-a and turbidity models could validly be applied to a vast majority of Ohio River and Licking River pixels, application of these models to Little Miami River pixels was inappropriate due to an unmodeled source of spectral variation.

Stork, Christopher Lyle; Autry, Bradley C. (U.S. Environmental Protection Agency)

2005-07-01

189

Isoform-level microRNA-155 target prediction using RNA-seq  

PubMed Central

Computational prediction of microRNA targets remains a challenging problem. The existing rule-based, data-driven and expression profiling approaches to target prediction are mostly approached from the gene-level. The increasing availability of RNA-seq data provides a new perspective for microRNA target prediction on the isoform-level. We hypothesize that the splicing isoform is the ultimate effector in microRNA targeting and that the proposed isoform-level approach is capable of predicting non-dominant isoform targets as well as their targeting regions that are otherwise invisible to many existing approaches. To test the hypothesis, we used an iterative expectation maximization (EM) algorithm to quantify transcriptomes at the isoform-level. The performance of the EM algorithm in transcriptome quantification was examined in simulation studies using FluxSimulator. We used joint evidence from isoform-level down-regulation and seed enrichment to predict microRNA-155 targets. We validated our computational approach using results from 149 in-house performed in vitro 3?-UTR assays. We also augmented the splicing database using exon–exon junction evidence, and applied the EM algorithm to predict and quantify 1572 cell line specific novel isoforms. Combined with seed enrichment analysis, we predicted 51 novel microRNA-155 isoform targets. Our work is among the first computational studies advocating the isoform-level microRNA target prediction.

Deng, Nan; Puetter, Adriane; Zhang, Kun; Johnson, Kristen; Zhao, Zhiyu; Taylor, Christopher; Flemington, Erik K.; Zhu, Dongxiao

2011-01-01

190

The efficient prediction of shallow water flows Part 1: Theory  

Microsoft Academic Search

Finite difference schemes are presented for the solution of the one-dimensional shallow water equations in open channels, and the two-dimensional shallow water equations. The numerical results are subsequently compared for a range of problems.

P. Glaister

1996-01-01

191

Great Lakes Water Levels 1973. Daily and Monthly Average Water Surface Elevations.  

National Technical Information Service (NTIS)

The publication contains Lake Survey Center Great Lakes water level gage records and shows in tabular form daily and monthly average levels for each gage in the network for the calendar year. It also contains, in a separate table, the highest and lowest d...

1974-01-01

192

Great Lakes Water Levels 1974. Daily and Monthly Average Water Surface Elevations.  

National Technical Information Service (NTIS)

The publication contains Lake Survey Center Great Lake water-level gage records and shows in tabular form daily and monthly average levels for each gage in the network for the calendar year. It also contains, in a separate table, the highest and lowest da...

1975-01-01

193

Great Lakes Water Levels--1972. Daily and Monthly Average Water Surface Elevations.  

National Technical Information Service (NTIS)

The publication contains Lake Survey Center Great Lakes water level gage records and shows in tabular form daily and monthly average levels for each gage in the network for the calendar year. It also contains, in a separate table, the highest and lowest d...

1973-01-01

194

Heavy metal levels in fish from coastal waters of Uruguay.  

PubMed

Copper, mercury, and zinc levels were determined in muscle and liver (N = 163) of seven fish species caught in coastal waters off Montevideo and Piriapolis (control site): Odontesthes spp., Mugil platanus, Micropogonias furnieri, Urophycis brasiliensis, Cynoscion guatucupa, Menticirrhus americanus, and Mustelus schmitti. The local population commonly uses these species for consumption. Heavy metal concentrations determined in this study were generally below those obtained for fish caught in Argentinean and Brazilian coastal waters, with some exceptions in the case of mercury and zinc. Based on copper, mercury, and zinc levels in muscle tissue, we conclude that the fish studied here are acceptable for human consumption. Nevertheless, it is recommended not to consume the fish liver (up to 466 microg Zn g(-1) dry weight in liver) nor large specimens of the investigated species. Regional programs involving the neighboring countries should be established to assess the fisheries resources and potential risks for human health. PMID:15883670

Viana, F; Huertas, R; Danulat, E

2005-03-28

195

Influence of scattering phenomena on the solar zenith angle dependence of in-water irradiance levels  

SciTech Connect

A Monte Carlo analysis is utilized to determine the influence of the inherent properties of a water mass on the solar zenith angle dependence of subsurface irradiance levels. It is shown that the proportion of scattering interactions (as represented by the scattering albedo ..omega..) has a greater influence on this dependence that does the backscattering probability B. Several representations of direct and/or diffuse incident radiation are considered, and their effects on the solar zenith angle dependence are evaluated. Irradiance level data collected in Lake Erie are compared to the predictions of the Monte Carlo analysis.

Jerome, J.H.; Bruton, J.E.; Bukata, R.P.

1982-02-15

196

Simulated effects of pumping irrigation wells on ground-water levels in western Saginaw County, Michigan  

USGS Publications Warehouse

Success of agriculture in many areas of Michigan relies on withdrawal of large quantities of ground water for irrigation. In some areas of the State, water-level declines associated with large ground-water withdrawals may adversely affect nearby residential wells. Residential wells in several areas of Saginaw County, in Michigan?s east-central Lower Peninsula, recently went dry shortly after irrigation of crop lands commenced; many of these wells also went dry during last year?s agricultural cycle (summer 2000). In September 2000, residential wells that had been dry returned to function after cessation of pumping from large-capacity irrigation wells. To evaluate possible effects of ground-water withdrawals from irrigation wells on residential wells, the U.S. Geological Survey used hydrogeologic data including aquifer tests, water-level records, geologic logs, and numerical models to determine whether water-level declines and the withdrawal of ground water for agricultural irrigation are related. Numerical simulations based on representative irrigation well pumping volumes and a 3-month irrigation period indicate water-level declines that range from 5.3 to 20 feet, 2.8 to 12 feet and 1.7 to 6.9 feet at distances of about 0.5, 1.5 and 3 miles from irrigation wells, respectively. Residential wells that are equipped with shallow jet pumps and that are within 0.5 miles of irrigation wells would likely experience reduced yield or loss of yield during peak periods of irrigation. The actual extent that irrigation pumping cause reduced function of residential wells, however, cannot be fully predicted on the basis of the data analyzed because many other factors may be adversely affecting the yield of residential wells.

Hoard, Christopher J.; Westjohn, David B.

2001-01-01

197

Assessment of the impact of the Odra river water levels on groundwater levels in Rzeczyca region  

NASA Astrophysics Data System (ADS)

Groundwater table levels in a river valley depend, among other factors, on meteorological and hydrogeological conditions, land use and water levels in watercourses. The primary role of a watercourse is to collect surface and groundwater, and it becomes an infiltrating watercourse at high water levels. Changes in groundwater levels and the range of these changes depend chiefly on the shape, height and duration of the flood wave in the river channel. The assessment of flood wave impact on groundwater was based on long-term measurements of groundwater levels in the Odra valley and observations of water levels in the river channel. Simulations were performed with the use of in-house software FIZ (Filtracja i Zanieczyszczenia; Filtration and Contamination), designed for modelling unsteady water flows within a fully saturated zone. A two-dimensional model with two spatial variables was employed. The process of groundwater flow through a porous medium, non-homogeneous in terms of water permeability, was described with Boussinesq equation. The equation was solved with the use of finite element method. The model was applied to assess groundwater level fluctuations in the Odra valley in the context of actual flood waves on the river. Variations in groundwater table in the valley were analysed in relation to selected actual flood water levels in the Odra in 2001-2003 and 2010. The period from 2001 to 2003 was used to verify the model. A satisfactory agreement between the calculated and the measured values was obtained. Based on simulation calculations, it was proved that flood waves observed in 2010 caused a rise in groundwater table levels in a belt of approximately 1000 metres from the watercourses. It was calculated that at the end of hydrological year 2009/2010, the highest growths, of up to 0.80 m, were observed on piezometers located close to the Odra river channel. The passage of several flood waves on the Odra caused an increase of subsurface retention by 3.0% compared to the initial state.

Chalfen, Mieczys?aw; G?uchowska, Beata; P?ywaczyk, Leszek

2012-10-01

198

Towards quantification of uncertainty in predicting water quality failures in integrated catchment model studies  

Microsoft Academic Search

This paper describes the development and application of a method for estimating uncertainty in the prediction of sewer flow quantity and quality and how this may impact on the prediction of water quality failures in integrated catchment modelling (ICM) studies. The method is generic and readily adaptable for use with different flow quality prediction models that are used in ICM

A. N. A. Schellart; S. J. Tait; R. M. Ashley

2010-01-01

199

Prediction of environmental parameters by adsorbability index: Water solubilities of hydrophobic organic pollutants  

SciTech Connect

The adsorbability index proposed by Abe et al. to predict the activated carbon adsorption of organic compounds from aqueous solutions was found to be an effective parameter for predicting the water solubilities of 265 hydrophobic organic pollutants which were classified into 118 aliphatic compounds and 88 mono- and 59 polynuclear aromatic compounds; and, furthermore, for predicting the total molecular surface areas of these compounds.

Okouchi, S.; Saegusa, H.; Nojima, O. (Hosei Univ., Tokyo (Japan))

1992-01-01

200

Predicting homework time management at the secondary school level: A multilevel analysis  

Microsoft Academic Search

The purpose of this study is to test empirical models of variables posited to predict homework time management at the secondary school level. Student- and class-level predictors of homework time management were analyzed in a survey of 1895 students from 111 classes. Most of the variance in homework time management occurred at the student level, with parent education appearing as

Jianzhong Xu

2010-01-01

201

Predicting Homework Time Management at the Secondary School Level: A Multilevel Analysis  

ERIC Educational Resources Information Center

|The purpose of this study is to test empirical models of variables posited to predict homework time management at the secondary school level. Student- and class-level predictors of homework time management were analyzed in a survey of 1895 students from 111 classes. Most of the variance in homework time management occurred at the student level,…

Xu, Jianzhong

2010-01-01

202

Functionally Layered Video Coding for Water Level Monitoring  

NASA Astrophysics Data System (ADS)

This paper proposes a new type of layered video coding especially for the use of monitoring water level of a river. A sensor node of the system decomposes an input video signal into some kinds of component signals and produces a bit stream functionally separated into three layers. The first layer contains the minimum components effective for detecting the water level. It is transmitted at very low bit rate for regular monitoring. The second layer contains signals for thumb-nail video browsing. The third layer contains additional data for decoding the original video signal. These are transmitted in case of necessity. A video signal is decomposed into several bands with the three dimensional Haar transform. In this paper, optimum bands to be contained into the 1st layer are experimentally investigated considering both of water level detection and data size to be transmitted. As a result, bit rate for transmitting the first layer is reduced by 32.5% at the cost of negligible 3.7% decrease of recognition performance for one of video examples.

Udomsiri, Sakol; Iwahashi, Masahiro; Muramatsu, Shogo

203

Prediction of the Caspian Sea level using ECMWF seasonal forecasts and reanalysis  

NASA Astrophysics Data System (ADS)

The hydrological budget of the Caspian Sea (CS) is investigated using the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERAi) and seasonal forecast (FCST) data with the aim of predicting the Caspian Sea Level (CSL) some months ahead. Precipitation and evaporation are used. After precipitation events over the Volga River, the discharge (Volga River discharge (VRD)) follows with delays, which are parameterized. The components of the water budget from ERAi and FCSTs are integrated to obtain time series of the CSL. Observations of the CSL and the VRD are used for comparison and tuning. The quality of ERAi data is sufficiently good to calculate the time variability of the CSL with a satisfactory accuracy. Already the storage of water within the Volga Basin allows forecasts of the CSL a few months ahead, and using the FCSTs of precipitation improves the CSL forecasts. The evaporation in the seasonal forecasts is deficient due to unrealistic sea surface temperatures over the CS. Impacts of different water budget terms on the CSL variability are shown by a variety of validation tools. The importance of precipitation anomalies over the catchment of the Volga River is confirmed, but also impacts from the two southern rivers (Sefidrud and Kura River) and the evaporation over the CS become obvious for some periods. When pushing the FCSTs beyond the limits of the seasonal FCSTs to 1 year, considerable forecast skill can still be found. Validating only FCSTs by the present approach, which show the same trend as one based on a statistical method, significantly enhances the skill scores.

Arpe, K.; Leroy, S. A. G.; Wetterhall, F.; Khan, V.; Hagemann, S.; Lahijani, H.

2013-08-01

204

Modeled impacts of predicted climate change on recharge and groundwater levels  

NASA Astrophysics Data System (ADS)

A methodology is developed for linking climate models and groundwater models to investigate future impacts of climate change on groundwater resources. An unconfined aquifer, situated near Grand Forks in south central British Columbia, Canada, is used to test the methodology. Climate change scenarios from the Canadian Global Coupled Model 1 (CGCM1) model runs are downscaled to local conditions using Statistical Downscaling Model (SDSM), and the change factors are extracted and applied in LARS-WG stochastic weather generator and then input to the recharge model. The recharge model simulated the direct recharge to the aquifer from infiltration of precipitation and consisted of spatially distributed recharge zones, represented in the Hydrologic Evaluation of Landfill Performance (HELP) hydrologic model linked to a geographic information system (GIS). A three-dimensional transient groundwater flow model, implemented in MODFLOW, is then used to simulate four climate scenarios in 1-year runs (1961-1999 present, 2010-2039, 2040-2069, and 2070-2099) and compare groundwater levels to present. The effect of spatial distribution of recharge on groundwater levels, compared to that of a single uniform recharge zone, is much larger than that of temporal variation in recharge, compared to a mean annual recharge representation. The predicted future climate for the Grand Forks area from the downscaled CGCM1 model will result in more recharge to the unconfined aquifer from spring to the summer season. However, the overall effect of recharge on the water balance is small because of dominant river-aquifer interactions and river water recharge.

Scibek, J.; Allen, D. M.

2006-11-01

205

EPSAC Predictive Control of Blood Glucose Level in Type I Diabetic Patients  

Microsoft Academic Search

An in-house predictive control algorithm has been implemented to control blood glucose level in type I diabetic patients, by controlling the insulin infusion rate to a mechanical pump. The role of the disturbance filter in model-based predictive control is underlined and its possibility to improve control performance is exploited. For comparison purposes, a classic PID controller has been designed via

Clara Ionescu; Robin De Keyser

2005-01-01

206

Protinfo PPC: A web server for atomic level prediction of protein complexes  

Microsoft Academic Search

Protinfo PPC' (Prediction of Protein Complex) is a web server that predicts atomic level structures of interacting proteins from their amino-acid sequences. It uses the interolog method to search for experimental protein complex structures that are homologous to the input sequences submitted by a user. These structures are then used as starting templates to generate protein complex models, which are

Weerayuth Kittichotirat; Michal Guerquin; Roger Eugene Bumgarner; Ram Samudrala

2009-01-01

207

Partitioning impacts of climate and regulation on water level variability in Great Slave Lake  

Microsoft Academic Search

Water level observations and a daily water balance model are used to build a naturalized water level history for Great Slave Lake dating back to the 1967 completion of the W.A.C. Bennett Dam in the Peace River basin headwaters. Comparison of water level observations dating back to 1938 and water balance scenarios for 1964 1998 assist in constraining the probable

J. J. Gibson; T. D. Prowse; D. L. Peters

2006-01-01

208

Efficacy of two Measures of Relative Sea Level in Predicting Stratal Geometry and Surface Morphology in an Experiment with Varying Base Level  

NASA Astrophysics Data System (ADS)

Using experimental data, we compare two methods of measuring relative sea level as predictors of stratal and surface morphology. The first method is the "local" relative sea level (LRSL), defined as the sum of rate of eustatic sea level change and local subsidence rate. The second is the shoreline-following RSL (SFRSL), which is the local RSL evaluated at the shoreline as the shoreline moves across the depositional surface. The two methods are compared using data from an experiment conducted in the eXperimental EarthScape (XES) facility at St. Anthony Falls Laboratory, University of Minnesota, Minneapolis. The experiment was designed to investigate morphodynamic and stratigraphic response to both isolated and superimposed slow and rapid base-level cycles, in a fluvial deltaic system. The experimental system was subject to steady, nonuniform passive-margin style subsidence and constant rates of sediment and water supply. The experimental conditions were ideal for evaluating and comparing these two measures of relative sea level. We find that the LRSL variation does a good job predicting overall stratal preservation of sea level cycles as a function of downstream position in the basin: preserved cycle thickness is predicted well using the relative vertical distances between successive diminishing minima in the LRSL curve at each position. On the other hand, the SFRSL correlates well to the temporal history of incised valley initiation and development.

Strong, N.; Sheets, B. A.; Wonsuck, K.; Kelberer, M.; Paola, C.

2003-12-01

209

Assessment and prediction of contaminant migration in ground water from chromite waste dump  

NASA Astrophysics Data System (ADS)

Sukinda chromite valley is one of the largest chromite deposits of the country and produces nearly 8% of chromite ore. It greatly contributes towards the economic development but at the same time deteriorates the natural environment. It is generally excavated by opencast mining method. In the Sukinda mining area, around 7.6 million tons of solid waste have been generated in the form of rejected minerals, overburden material/waste rock and sub-grade ore that may be resulting in environmental degradation, mainly causing lowering in the water table vis-à-vis deterioration in surface and ground water quality. The study conducted in and around one of the chromite mine of the valley reveals that the concentration of hexavalent chromium is found in the water samples of ground and surface water, mine effluents and seepage water. Hexavalent Chromium (Cr+6) have been found varying between 0.02 mg/l and 0.12 mg/l in mine effluents and 0.03 0.8 mg/l in shallow hand pumps and 0.05 and 1.22 mg/l in quarry seepage. The concentration of Cr+6 in Damsal nalah, the main surface water source in the area, is found varying between 0.03 mg/l and 0.14 mg/l and a increasing trend, which is in the downstream of mining activities, has been observed. Leachate study clearly shows that the soil lying in the vicinity of mine waste dump shows highest concentration of Cr+6. Contaminant migration in ground water depends upon various geohydrological conditions of the area. The study shows that aquifer resistivity varies between 15 ?m to 150 ?m and aquifer depth varies from 4 m to 26 m below ground level. The ground water flow and mass transport models were constructed with the help of geo-hydrological and geophysical informations using Visual Modflow software. Contaminant migration and path lines for 20 years have been predicted in two layers model of ground water. The study provided an insight into the likely migration of contaminant in ground water due to leaching from overburden dump of chromite ore and will be helpful in making strategic planning for limiting the contaminant migration in the ground water regime in and around the mining areas.

Tiwary, R. K.; Dhakate, R.; Ananda Rao, V.; Singh, V. S.

2005-08-01

210

Fuzzy neural network model applied in the mine water inrush prediction  

NASA Astrophysics Data System (ADS)

Combining with fuzzy reasoning, neural network and back propagation algorithm, a fuzzy neural network model for the prediction of mine water inrush is built after the analysis of the main factors affected the mine water inrush, such as water pressure, fault throw, water conducted zone width, aquifer thickness and confining bed thickness. Then, on the basis of the water inrush mechanism and some practical examples, influential factors on mine water inrush are divided into three groups, and after that 81 fuzzy inference rules are constructed effectively. And then, the four-layer back propagation fuzzy neural network takes effect in training the input variables. Finally, a simulated prediction of the fuzzy neural network is made by using test samples. The results of simulation show that mine water inrush model based on fuzzy neural network is superior to the traditional BP neural network on training speed and predicting precision.

Xiao, Jian-Yu; Tong, Min-Ming; Fan, Qi; Zhu, Chang-Jie

2010-08-01

211

The application of a Grey Markov Model to forecasting annual maximum water levels at hydrological stations  

NASA Astrophysics Data System (ADS)

Compared with traditional real-time forecasting, this paper proposes a Grey Markov Model (GMM) to forecast the maximum water levels at hydrological stations in the estuary area. The GMM combines the Grey System and Markov theory into a higher precision model. The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values, and thus gives forecast results involving two aspects of information. The procedure for forecasting annul maximum water levels with the GMM contains five main steps: 1) establish the GM (1, 1) model based on the data series; 2) estimate the trend values; 3) establish a Markov Model based on relative error series; 4) modify the relative errors caused in step 2, and then obtain the relative errors of the second order estimation; 5) compare the results with measured data and estimate the accuracy. The historical water level records (from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin, China are utilized to calibrate and verify the proposed model according to the above steps. Every 25 years' data are regarded as a hydro-sequence. Eight groups of simulated results show reasonable agreement between the predicted values and the measured data. The GMM is also applied to the 10 other hydrological stations in the same estuary. The forecast results for all of the hydrological stations are good or acceptable. The feasibility and effectiveness of this new forecasting model have been proved in this paper.

Dong, Sheng; Chi, Kun; Zhang, Qiyi; Zhang, Xiangdong

2012-03-01

212

A screening level fate model of organic contaminants from advanced water treatment in a potable water supply reservoir.  

PubMed

Augmentation of potable water sources by planned indirect potable reuse of wastewater is being widely considered to address growing water shortages. Environmental buffers such as lakes and dams may act as one of a series of barriers to potable water contamination stemming from micropollutants in wastewater. In South-East Queensland, Australia, current government policy is to begin indirect potable reuse of water from reverse osmosis equipped advanced water treatment plants (AWTPs) when the combined capacity of its major storages is at 40% capacity. A total of 15 organic contaminants including NDMA and bisphenol A have been publically reported as detected in recycled water from one of South-East Queensland's AWTPs, while another 98 chemicals were analysed for, but found to be below their detection limit. To assess the natural attenuation in Lake Wivenhoe, a Level III fugacity based evaluative fate model was constructed using the maximum concentrations of these contaminants detected as input data. A parallel aquivalence based model was constructed for those contaminants, such as dichloroacetic acid, dalapon and triclopyr, which are ionised in the environment of Lake Wivenhoe. A total of 247 organic chemicals of interest, including disinfection by-products, pesticides, pharmaceuticals and personal care products, xenoestrogens and industrial chemicals, were evaluated with the model to assess their potential for natural attenuation. Out of the 15 detected chemicals, trihalomethanes are expected to volatilise with concentrations in the outflow from the dam approximately 400 times lower than influent from the AWTPs. Transformation processes in water are likely to be more significant for NDMA and pharmaceuticals such as salicylic acid and paracetamol as well as for caffeine and the herbicides dalapon and triclopyr. For hydrophobic contaminants such as cholesterol and phenolic xenoestrogens such as 4-nonylphenol, 4-t-octylphenol and bisphenol A, equilibrium between water and sediments will not be attained and hence fate processes such as removal in outflow are predicted to become relatively important. PMID:20851445

Hawker, Darryl W; Cumming, Janet L; Neale, Peta A; Bartkow, Michael E; Escher, Beate I

2010-09-08

213

Prediction of water quality in lakes and reservoirs. Part I — Model description  

Microsoft Academic Search

A one-dimensional water quality model (DYRESM Water Quality) is described which combines a process based hydrodynamic model (DYRESM) with numerical descriptions of phytoplankton production, nutrient cycling, the oxygen budget and particle dynamics. The hydrodynamic component is free from calibration, which ensures that it is readily transferable to other lakes and reservoirs. This improves water quality predictions derived for different hydrodynamic

David P. Hamilton; S. Geoffrey Schladow

1997-01-01

214

Predictive Analyses of Ground-Water Discharges in the Willow Creek Watershed, Northeast Nebraska.  

National Technical Information Service (NTIS)

Ground-water discharge to Willow Creek in northeast Nebraska was predicted with a digital model of the ground-water/surface-water system. Recharge and irrigation requirements were determined with a model of the soil zone. Where the regional aquifer is unc...

J. T. Dugan E. G. Lappala

1978-01-01

215

Prediction of Air?Water Interfacial Area in Wet Unsaturated Porous Media  

Microsoft Academic Search

A numerical model is developed to predict the air-water interfacial area of water-wetted unsaturated porous media. A model space is first designed consisting of elements capable of containing a single material. Water, air, and quartz are considered in this work. The elements are square in two dimensions and cubic in three dimensions. The contents of elements containing quartz are considered

David L. Silverstein; Tomlinson Fort

2000-01-01

216

Predicting water's phase diagram and liquid-state anomalies  

Microsoft Academic Search

Water expands upon freezing, has minima in its volume, heat capacity, and isothermal compressibility with temperature, and shows signs of a first-order phase transition when supercooled. We present an analytical molecular theory that can account for these behaviors. It suggests that local network formation and hydrogen-bonding cooperativity between triplets of neighboring molecules are keys to understanding water's thermodynamics.

Thomas M. Truskett; Ken A. Dill

2002-01-01

217

COMMUNICATIONS Predicting water's phase diagram and liquid-state anomalies  

Microsoft Academic Search

Water expands upon freezing, has minima in its volume, heat capacity, and isothermal compressibility with temperature, and shows signs of a first-order phase transition when supercooled. We present an analytical molecular theory that can account for these behaviors. It suggests that local network formation and hydrogen-bonding cooperativity between triplets of neighboring molecules are keys to understanding water's thermodynamics. © 2002

Thomas M. Trusketta; Ken A. Dill

218

Application of data assimilation for improving forecast of water levels and residual currents in Singapore regional waters  

NASA Astrophysics Data System (ADS)

Hydrodynamic models are commonly used for predicting water levels and currents in the deep ocean, ocean margins and shelf seas. Their accuracy is typically limited by factors, such as the complexity of the coastal geometry and bathymetry, plus the uncertainty in the flow forcing (deep ocean tide, winds and pressure). In Southeast Asian waters with its strongly hydrodynamic characteristics, the lack of detailed marine observations (bathymetry and tides) for model validation is an additional factor limiting flow representation. This paper deals with the application of ensemble Kalman filter (EnKF)-based data assimilation with the purpose of improving the deterministic model forecast. The efficacy of the EnKF is analysed via a twin experiment conducted with the 2D barotropic Singapore regional model. The results show that the applied data assimilation can improve the forecasts significantly in this complex flow regime.

Karri, Rama Rao; Badwe, Abhijit; Wang, Xuan; El Serafy, Ghada; Sumihar, Julius; Babovic, Vladan; Gerritsen, Herman

2013-01-01

219

Prediction for Changing of Sea Level near Lingang New City in Shanghai  

Microsoft Academic Search

To predict Changing of Sea Level near Lingang New City in Shanghai, a model for global sea-level rise was established firstly and calculated with Maple. It is showed: the global sea level rise rate in 2009 is 2.68mm\\/a. The height and rate of global sea-level rise will be about 9.11cm and 3.22mm\\/a in 2020. Based on the study and the

Yi Zheng; Jing Wang

2010-01-01

220

System Identification and Multi-Level Optimization of Integrated Ground Water Systems.  

National Technical Information Service (NTIS)

Conjunctive surface water and ground water systems are analyzed using the techniques of system identification and multi-level optimization. Mathematical models describing the behavior of the ground water regime are developed. Given historic ground water l...

J. A. Dracup

1974-01-01

221

Amount of leachant and water absorption levels of wood treated with borates and water repellents.  

PubMed

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA. PMID:16359861

Baysal, Ergun; Sonmez, Abdullah; Colak, Mehmet; Toker, Hilmi

2005-12-15

222

Screening Experiments for Removal of Low-Level Tritiated Water  

SciTech Connect

Screening experiments for low levels of tritiated water (HTO) remediation based upon selective adsorption/desorption mechanisms utilizing equilibrium isotope effects have been carried out. Several organic and inorganic high surface area materials were investigated to assess their ability to selectively adsorb low concentrations of HTO. Ion-exchange resins with cation functionalities, chitosan, sodium alginate, and several inorganic media modified with metal cations exhibited promising results. Biomaterials, for example, chitosan and modified alginate, demonstrated positive results. Based on the literature and our preliminary testing, we postulate four possible mechanisms for selected tritium adsorption: hydrogen ion exchange, HTO coordination with surface cation sites, hydrogen bonding to surface basic sites, and secondary hydrogen bonding (structural water) in fine pores.

Kim, Yun Mi; Baney, Ronald; Powers, Kevin; Koopman, Ben; Tulenko, James [University of Florida (United States)

2005-03-15

223

Predicting water quality criteria for protecting aquatic life from physicochemical properties of metals or metalloids.  

PubMed

Metals are widely distributed pollutants in water and can have detrimental effects on some aquatic life and humans. Over the past few decades, the United States Environmental Protection Agency (U.S. EPA) has published a series of criteria guidelines, which contain specific criteria maximum concentrations (CMCs) for 10 metals. However, CMCs for other metals are still lacking because of financial, practical, or ethical restrictions on toxicity testing. Herein, a quantitative structure activity relationship (QSAR) method was used to develop a set of predictive relationships, based on physical and chemical characteristics of metals, and predict acute toxicities of each species for five phyla and eight families of organisms for 25 metals or metalloids. In addition, species sensitivity distributions (SSDs) were developed as independent methods for determining predictive CMCs. The quantitative ion character-activity relationships (QICAR) analysis showed that the softness index (?p), maximum complex stability constants (log -?(n)), electrochemical potential (?E(0)), and covalent index (X(m)(2)r) were the minimum set of structure parameters required to predict toxicity of metals to eight families of representative organisms. Predicted CMCs for 10 metals are in reasonable agreement with those recommended previously by U.S. EPA within a difference of 1.5 orders of magnitude. CMCs were significantly related to ?p (r(2) = 0.76, P = 7.02 × 10(-9)) and log -?(n) (r(2) = 0.73, P = 3.88 × 10(-8)). The novel QICAR-SSD model reported here is a rapid, cost-effective, and reasonably accurate method, which can provide a beneficial supplement to existing methodologies for developing preliminarily screen level toxicities or criteria for metals, for which little or no relevant information on the toxicity to particular classes of aquatic organisms exists. PMID:23199259

Wu, Fengchang; Mu, Yunsong; Chang, Hong; Zhao, Xiaoli; Giesy, John P; Wu, K Benjamin

2012-12-10

224

Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters.  

National Technical Information Service (NTIS)

It is the long-term goal of this work to evaluate our understanding of CDOM sources and distributions in coastal waters by comparing high- resolution observations with four-dimensional, physical, chemical and biological models of the CDOM fields.

G. B. Gardner R. F. Chen Y. Tian

2008-01-01

225

Personality disorders and the five-factor model: a test of facet-level predictions.  

PubMed

We tested predicted relationships (Widiger, 1993; Widiger, Trull, Clarkin, Sanderson, & Costa, 1994) between personality disorder scores and facets of the five-factor model, and evaluated the relative benefits of facet-level analyses over domain-level analyses. Data from 614 undergraduates indicated: (a) 63% of the predicted facet relationships were significant, although many unpredicted relationships also emerged; (b) facet-level analyses did not yield substantially stronger effect sizes than domain-level analyses; but (c) facet-level analyses provided much better discrimination between personality disorders than domain-level analyses. Facets of the openness to experience domain also helped discriminate between personality disorders, which is in contrast to previous domain-level findings that openness is not important. PMID:9573518

Dyce, J A; O'Connor, B P

1998-01-01

226

Predicting Fire Suppression Efficiency Using Polydisperse Water Sprays  

Microsoft Academic Search

Thermoplastic fire suppression by water sprays is numerically investigated using an Eulerian-Eulerian two-phase approach. The polydisperse spray model is based on the moments of the droplet size distribution function. Turbulent combustion is approached using the Arrhenius\\/Eddy-Break-up model coupled with the RNGk ? ? turbulence model. A multiphase radiative transfer equation including the contributions of soot, combustion products and water droplets is used

F. Nmira; A. Kaiss; J.-L. Consalvi; B. Porterie

2008-01-01

227

Lifetime prediction of a blue PE100 water pipe  

Microsoft Academic Search

The traditional method to assess the lifetime of plastic pipes is based on hydrostatic pressure testing. A complementary approach has been conducted to monitor the depletion of antioxidants and initiation of thermo-oxidative degradation on a PE100 blue water pipe that had been exposed to hydrostatic pressure in water at low test temperatures (maximum 80°C).Depletion of antioxidants was monitored using OIT

Eric M. Hoàng; David Lowe

2008-01-01

228

Non Invasive Water Level Monitoring on Boiling Water Reactors Using Internal Gamma Radiation: Application of Soft Computing Methods  

Microsoft Academic Search

To provide best knowledge about safety-related water level values in boiling water reactors (BWR) is essentially for operational regime. For the water level determination hydrostatic level measurement systems are almost exclusively applied, because they stand the test over many decades in conventional and nuclear power plants (NPP). Due to the steam generation especially in BWR a specific phenomenon occurs which

Sebastian Fleischer; Rainer Hampel

2006-01-01

229

Predicting Impacts of Increased CO2 and Climate Change on the Water Cycle and Water Quality in the Semiarid James River Basin of the Midwestern USA  

USGS Publications Warehouse

Emissions of greenhouse gases and aerosols from human activities continue to alter the climate and likely will have significant impacts on the terrestrial hydrological cycle and water quality, especially in arid and semiarid regions. We applied an improved Soil and Water Assessment Tool (SWAT) to evaluate impacts of increased atmospheric CO2 concentration and potential climate change on the water cycle and nitrogen loads in the semiarid James River Basin (JRB) in the Midwestern United States. We assessed responses of water yield, soil water content, groundwater recharge, and nitrate nitrogen (NO3–N) load under hypothetical climate-sensitivity scenarios in terms of CO2, precipitation, and air temperature. We extended our predictions of the dynamics of these hydrological variables into the mid-21st century with downscaled climate projections integrated across output from six General Circulation Models. Our simulation results compared against the baseline period 1980 to 2009 suggest the JRB hydrological system is highly responsive to rising levels of CO2 concentration and potential climate change. Under our scenarios, substantial decrease in precipitation and increase in air temperature by the mid-21st century could result in significant reduction in water yield, soil water content, and groundwater recharge. Our model also estimated decreased NO3–N load to streams, which could be beneficial, but a concomitant increase in NO3–N concentration due to a decrease in streamflow likely would degrade stream water and threaten aquatic ecosystems. These results highlight possible risks of drought, water supply shortage, and water quality degradation in this basin.

Yiping Wu; Liu , Shuguang; Gallant, Alisa L.

2012-01-01

230

Prediction of maximum daily ozone level using combined neural network and statistical characteristics  

Microsoft Academic Search

Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. As one of major pollutants, ozone, especially ground level ozone, is responsible for various adverse effects on both human being and foliage. Therefore, prediction of ambient ozone levels in certain environment, especially the ground ozone

Wenjian Wang; Weizhen Lu; Xiekang Wang; Andrew Y. t. Leung

2003-01-01

231

Concurrent and Predictive Relations between Hormone Levels and Social-Emotional Functioning in Early Adolescence.  

ERIC Educational Resources Information Center

|Hormone levels and changes in hormone levels were evaluated three times across a 1-year period as concurrent and predictive correlates of the socio-emotional functioning of 56 boys 10- to 14-years-old and 52 girls 9- to 14-years-old who represented the five stages of Tanner's criteria of pubertal development. The hormone measures were serum…

Nottelmann, Editha D.; And Others

232

Effects of Educational Level on Prediction of Training Success with the ACB(Army Classification Battery).  

National Technical Information Service (NTIS)

The publication reports on a statistical analysis of educational level as it affects the prediction of enlisted performance in Army training courses. Samples of the men at each of four educational levels were formed: non-high school graduation, high schoo...

M. H. Maier

1972-01-01

233

Brain Natriuretic Peptide Levels Predict Perioperative Events in Cardiac Patients Undergoing Noncardiac Surgery: A Prospective Study  

Microsoft Academic Search

Objectives: Brain natriuretic peptide (BNP) levels correlate with prognosis in patients with cardiac disease and may be useful in the risk stratification of cardiac patients undergoing noncardiac surgery (NCS). The objective of this study was to examine whether BNP levels predict perioperative events in cardiac patients undergoing NCS. Methods: Patients undergoing NCS with at least 1 of the following criteria

David Leibowitz; David Planer; David Rott; Yair Elitzur; Tova Chajek-Shaul; A. Teddy Weiss

2008-01-01

234

Predicting shallow water table depth at regional scale from rainfall and soil data  

NASA Astrophysics Data System (ADS)

We model the spatio-temporal changes of shallow water table depth at regional scale. The model assumes a sinusoidal behavior of the water table with a bimodal yearly cycle. The predictive tool is based on cumulative rainfall data and long term water table characteristics. Integrating soil information will increase the accuracy of the model. Spatio-temporal maps of the water table depth will be used to optimize irrigation management.

Calzolari, Costanza; Ungaro, Fabrizio

2012-01-01

235

Water Level Changes on the Central Amazon Floodplain Measured with Interferometric JERS-1 SAR Data  

NASA Astrophysics Data System (ADS)

The central Amazon floodplain is marked by non-channelized, diffusive flow conditions that prohibit the use of typical in-situ gauging methods for estimating discharge (e.g., rating-curves). In fact, gauging stations are located only on the mainstem and major tributaries, but not in the adjoining floodplains. Logistics and costs prohibit the installation of floodplain gauges, thus predictions of floodplain storage and subsequent discharge evolve from models, such as Muskingum methods, or from remote sensing. Interferometric processing of SIR-C SAR data has previously been used to demonstrate that water levels across the central Amazon floodplain are not horizontal, as assumed in a Muskingum model based approach. Yet, the interferometric SIR-C data exists only for a very brief, 24-hour period, and the method requires a "double-bounce" radar pulse travel path typical of flooded vegetation. Interferometric processing of JERS-1 SAR data over flooded forests of the floodplain provides net changes in water levels during the 44, 88, etc. day orbital repeat cycles. Interferometric coherence during these repeat-cycles is poor, but visible fringe patterns exist, even in unfiltered interferograms. Measured changes in water levels generally agree with channel gauges at Itapeau, Beruri, and Manacapuru, but within-floodplain fluctuations are not planar. Preliminary interpretation of the interferometric data suggests that during early rising water, inundation appears first as a patchwork bordered by small floodplain channels, whereas at mainstem peak stage, floodplain flow appears to sub-parallel the mainstem.

Alsdorf, D.

2003-12-01

236

Interactive effects of salinity and N on pepper yield, water use efficiency and root zone and drainage salinity: Experimental data and UNSATCHEM predictions  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of this study is to examine the effects of optimal and suboptimal N fertilizer levels in saline conditions on pepper plant and to predict the yield, soil water and drainage water EC and ETa using UNSATCHEM. The salinity effect on pepper plant biomass was statistically significant. Increasing...

237

Statistical procedures for determination and verification of minimum reporting levels for drinking water methods.  

PubMed

The United States Environmental Protection Agency's Office of Ground Water and Drinking Water has developed a single-laboratory quantitation procedure: the lowest concentration minimum reporting level (LCMRL). The LCMRL is the lowest true concentration for which future recovery is predicted to fall, with high confidence (99%), between 50% and 150%. The procedure takes into account precision and accuracy. Multiple concentration replicates are processed through the entire analytical method and the data are plotted as measured sample concentration (y-axis) versus true concentration (x-axis). If the data support an assumption of constant variance over the concentration range, an ordinary least-squares regression line is drawn; otherwise, a variance-weighted least-squares regression is used. Prediction interval lines of 99% confidence are drawn about the regression. At the points where the prediction interval lines intersect with data quality objective lines of 50% and 150% recovery, lines are dropped to the x-axis. The higher of the two values is the LCMRL. The LCMRL procedure is flexible because the data quality objectives (50-150%) and the prediction interval confidence (99%) can be varied to suit program needs. The LCMRL determination is performed during method development only. A simpler procedure for verification of data quality objectives at a given minimum reporting level (MRL) is also presented. The verification procedure requires a single set of seven samples taken through the entire method procedure. If the calculated prediction interval is contained within data quality recovery limits (50-150%), the laboratory performance at the MRL is verified. PMID:16433362

Winslow, Stephen D; Pepich, Barry V; Martin, John J; Hallberg, George R; Munch, David J; Frebis, Christopher P; Hedrick, Elizabeth J; Krop, Richard A

2006-01-01

238

RELATIONSHIPS BETWEEN LEVELS OF HETEROTROPHIC BACTERIA AND WATER QUALITY PARAMETERS IN A DRINKING WATER DISTRIBUTION SYSTEM  

EPA Science Inventory

Conventional plating methods were used to quantify heterotrophic bacteria from a drinking water distribution system. Three media, plate count agar (PCA), R2A agar and sheep blood agar (TSA-SB) were used to determine heterotrophic plate count (HPC) levels. Grab samples were collec...

239

Using Holocene relative sea-level data to inform future sea-level predictions: An example from southwest England  

NASA Astrophysics Data System (ADS)

Holocene relative sea-level data contain information on vertical land movements along coasts and, hence, can provide vital input for predictions of future sea-level change. At Thurlestone, in southwest England, late Holocene coastal sediments were cored and sampled in coastal back-barrier marshes. The presence of a basal sedimentary unit containing salt-marsh microfossils made it possible to obtain precise estimates of late Holocene relative sea-level change from the sediments. This is important because previous studies have suggested that the southwest of England is experiencing the fastest rates of land subsidence in the British Isles. Ten new late Holocene basal sea-level index points fill an important gap in the palaeosea-level data set for southwest England. Another 15 early and middle Holocene sea-level index points are available from previous work. The data show that relative sea level rose by about 10 m between 9000 and 7000 cal. yr BP and a further 8 m in the last 7000 yr. In the last 2000 yr, relative sea level rose on average by 0.9 mm/yr. The coast is currently subsiding by 1.1 mm/yr due to ongoing glacial isostatic adjustment (GIA). The Bradley et al. (2009) GIA model, which is used in the United Kingdom to determine land-motion rates for input into future sea-level predictions, underestimates the rate of coastal subsidence by about 0.16 mm/yr, but performs better than other models. Our data validate the land-motion rates currently used in regional sea-level projections.

Gehrels, W. Roland; Dawson, David A.; Shaw, Jon; Marshall, William A.

2011-08-01

240

Prediction of noise levels and annoyance from aircraft run-ups at Vancouver International Airport.  

PubMed

Annoyance complaints resulting from engine run-ups have been increasing at Vancouver International Airport for several years. To assist the Airport in managing run-up noise levels, a prediction tool based on a Green's function parabolic equation (GFPE) model has been consolidated, evaluated, and applied. It was extended to include more realistic atmospheric and ground input parameters. Measurements were made of the noise-radiation characteristics of a CRJ200 jet aircraft. The GFPE model was validated by comparing predictions with results in the literature. A sensitivity analysis showed that predicted levels are relatively insensitive to small variations in geometry and ground impedance, but relatively sensitive to variations in wind speed, atmosphere type, and aircraft heading and power setting. Predicted noise levels were compared with levels measured at noise monitoring terminals. For the four cases for which all input information was available, agreement was within 10 dBA. For events for which some information had to be estimated, predictions were within 20 dBA. The predicted annoyance corresponding to the run-up events considered ranged from 1.8% to 9.5% of people awoken, suggesting that noise complaints can be expected. PMID:17902830

Scherebnyj, Katrina; Hodgson, Murray

2007-10-01

241

Forecasting the response of coastal wetlands to declining water levels and environmental disturbances in the Great Lakes  

Microsoft Academic Search

The overall purpose of this study was to examine the impact of increasing human-induced and natural stresses on the distribution of aquatic vegetation and fish along the Great Lake shoreline. ^ The first part of the dissertation proposes a predictive model to examine the effect of long-term water level fluctuations on the emergent plants in Lake Ontario coastal wetlands while

Anhua Wei

2007-01-01

242

Wind wave prediction in shallow water: Theory and applications  

SciTech Connect

A wind wave forecasting model is described, based upon the ray technique, which is specifically designed for shallow water areas. The model explicitly includes wave generation, refraction, and shoaling, while nonlinear dissipative processes (breaking and bottom fricton) are introduced through a suitable parametrization. The forecast is provided at a specified time and target position, in terms of a directional spectrum, from which the one-dimensional spectrum and the significant wave height are derived. The model has been used to hindcast storms both in shallow water (Northern Adriatic Sea) and in deep water conditions (Tyrrhenian Sea). The results have been compared with local measurements, and the rms error for the significant wave height is between 10 and 20%. A major problems has been found in the correct evaluation of the wind field.

Cavaleri, L.; Rizzoli, P.M.

1981-11-20

243

Advanced Methods for Modeling Water-Levels and Estimating Drawdowns with SeriesSEE, an Excel Add-In.  

National Technical Information Service (NTIS)

Water-level modeling is used for multiple-well aquifer tests to reliably differentiate pumping responses from natural water-level changes in wells, or environmental fluctuations. Synthetic water levels are created during water-level modeling and represent...

B. Mirus C. A. Garcia J. Fenelon K. Halford

2012-01-01

244

Measuring lake water level using multi-source remote sensing images combined with hydrological statistical data  

Microsoft Academic Search

The Poyang Lake, as one of the most frequently flooded area, is the largest freshwater lake in China. It is very significant to monitor the water level and water regime accurately and in real-time during flooding. To provide an operational method to measure shape parameters, such as water level, water regime area, and water distribution of Poyang Lake using remote

Qulin Tan; Siwen Bi; Jiping Hu; Zhengjun Liu

2004-01-01

245

PREDICTIVE MODELING OF LIGHT-INDUCED MORTALITY OF ENTEROCOCCI FAECALIS IN RECREATIONAL WATERS  

EPA Science Inventory

One approach to predictive modeling of biological contamination of recreational waters involves the application of process-based approaches that consider microbial sources, hydrodynamic transport, and microbial fate. This presentation focuses on one important fate process, light-...

246

Application of short-term water demand prediction model to Seoul.  

PubMed

To predict daily water demand for Seoul, Korea, the artificial neural network (ANN) was used. For the cross correlation, the factors affecting water demand such as maximum temperature, humidity, and wind speed as natural factors, holidays as a social factor and daily demand 1 day before were used. From the results of learning using various hidden layers and units in order to establish the structure of optimal ANN, the case of 3 hidden layers and numbers of unit with the same number of input factors showed the best result and, therefore, it was applied to seasonal water demand prediction. The performance of ANN was compared with a multiple regression method. We discuss the representation ability of the model building process and the applicability of the ANN approach for the daily water demand prediction. ANN provided reasonable results for time series prediction. PMID:12380999

Joo, C N; Koo, J Y; Yu, M J

2002-01-01

247

Predicting relative permeability from water retention: A direct approach based on fractal geometry  

Microsoft Academic Search

Commonly, a soil's relative permeability curve is predicted from its measured water retention curve by fitting equations that share parameters between the two curves (e.g., Brooks\\/Corey-Mualem and van Genuchten-Mualem). We present a new approach to predict relative permeability by direct application of measured soil water retention data without any fitting procedures. The new relative permeability model, derived from a probabilistic

Abdullah Cihan; John S. Tyner; Edmund Perfect

2009-01-01

248

Ground-water levels near the top of the water-table mound, western Cape Cod, Massachusetts, 2002-04  

USGS Publications Warehouse

In January 2002 the U.S. Geological Survey began continuous water-level monitoring in three wells in the vicinity of the Southeast Ranges of Camp Edwards, near the Impact Area of the Massachusetts Military Reservation on Cape Cod. The purpose of this effort was to examine how water levels at sites with different unsaturated-zone thicknesses near the top of the water-table mound beneath western Cape Cod are affected by temporally variable recharge from precipitation, which is the sole source of water to the sand and gravel aquifer. The depths to water at the well sites are about 18, 30, and 101 feet below land surface. This report presents the first 3 years of water-level records and an estimate of aquifer recharge calculated from climatological measurements by the Jensen and Haise method and the Thornthwaite method. The water levels in the three wells varied temporally by about 4.5 feet during the study period. A comparison of the water levels with those measured in a nearby monitoring well with about 42 years of monthly measurements indicates that the 3-year monitoring period included the lowest water levels on western Cape Cod since the drought of the 1960's. The response of water levels to recharge was related to the depth to water. Water levels in the two wells with shallow depths to water responded quickly (within hours or days) to recharge, whereas the water-level response in the well with the greatest depth to water often lagged the recharge event by a month or more. The variations in the water levels among the wells changed as the location of the top of the water-table mound moved with the changing water-table altitude.

Massey, Andrew J.; Carlson, Carl S.; LeBlanc, Denis R.

2006-01-01

249

Action reprogramming in Parkinson's disease: response to prediction error is modulated by levels of dopamine.  

PubMed

Humans are able to use knowledge of previous events to estimate the probability of future actions. Consequently, an unexpected event will elicit a prediction error as the prepared action has to be replaced by an unprepared option in a process known as "action reprogramming" (AR). Here we show that people with Parkinson's disease (PD) have a dopamine-sensitive deficit in AR that is proportional to the size of the prediction error. Participants performed a probabilistic reaction time (RT) task in the context of either a predictable or unpredictable environment. For an overall predictable sequence, PD patients, on and off dopamine medication, and healthy controls showed similar improvements in RT. However, in the context of a generally predictable sequence, PD patients off medication were impaired in reacting to unexpected events that elicit large prediction errors and require AR. Critically, this deficit in AR was modulated by the prediction error associated with the upcoming event. The prolongation of RT was not observed during an overall unpredictable sequence, in which relatively unexpected events evoke little prediction error and the requirement for AR should be minimal, given the context. The data are compatible with recent theoretical accounts suggesting that levels of dopamine encode the reliability, i.e., precision, of sensory information. In this scheme, PD patients off medication have low dopamine levels and may therefore be less confident about incoming sensory information and more reliant on top-down predictions. Consequently, when these internal predictions are incorrect, PD patients take longer to respond appropriately to unexpected sensory information. PMID:22238089

Galea, Joseph M; Bestmann, Sven; Beigi, Mazda; Jahanshahi, Marjan; Rothwell, John C

2012-01-11

250

Using hyperspectral imagery to predict post-wildfire soil water repellency  

NASA Astrophysics Data System (ADS)

A principal task of evaluating large wildfires is to assess fire's effect on the soil in order to predict the potential watershed response. Two types of soil water repellency tests, the water drop penetration time (WDPT) test and the mini-disk infiltrometer (MDI) test, were performed after the Hayman Fire in Colorado, in the summer of 2002 to assess the infiltration potential of the soil. Remotely sensed hyperspectral imagery was also collected to map post-wildfire ground cover and soil condition. Detailed ground cover measurements were collected to validate the remotely sensed imagery and to examine the relationship between ground cover and soil water repellency. Percent ash cover measured on the ground was significantly correlated to WDPT ( r = 0.42; p-value < 0.0001), and the MDI test ( r = - 0.37; p-value < 0.0001). A Mixture Tuned Matched Filter (MTMF) spectral unmixing algorithm was applied to the hyperspectral imagery, which produced fractional cover maps of ash, soil, and scorched and green vegetation. The remotely sensed ash image had significant correlations to the water repellency tests, WDPT ( r = 0.24; p-value = 0.001), and the MDI test ( r = - 0.21; p-value = 0.005). An iterative threshold analysis was also applied to the ash and water repellency data to evaluate the relationship at increasingly higher levels of ash cover. Regression analysis between the means of grouped data: MDI time vs. ash cover data ( R2 =0.75) and vs. Ash MTMF scores ( R2 = 0.63) yielded significantly stronger relationships. From these results we found on-the-ground ash cover greater than 49% and remotely sensed ash cover greater than 33% to be indicative of strongly water repellent soils. Combining these results with geostatistical analyses indicated a spatial autocorrelation range of 15 to 40 m. Image pixels with high ash cover (> 33%), including pixels within 15 m of these pixel patches, were used to create a likelihood map of soil water repellency. This map is a good indicator of areas where soil experienced severe fire effects—areas that likely have strong water repellent soil conditions and higher potential for post-fire erosion.

Lewis, Sarah A.; Robichaud, Peter R.; Frazier, Bruce E.; Wu, Joan Q.; Laes, Denise Y. M.

2008-03-01

251

Evaluation of Rock Mass Responses Using High Resolution Water-level Tiltmeter Arrays  

NASA Astrophysics Data System (ADS)

External forces act on the surface of the earth and produce deformation across all spatial and temporal scales. This research study focuses on the deformation evaluation of the rock-mass subjected to tidal, earthquake and surface forces. The events are monitored over horizontal distances of over 100 meters with tilt measurement arrays with a resolution of 10-8 radians. These measurements are obtained from hydrostatic leveling system (HLS) arrays that have been installed in the LaFarge mine in North Aurora, IL by Fermilab. Each sensor in the array is equipped with a water-filled reservoir beneath a capacitor. The amount of water in the reservoir is calculated as a function of the measured capacitance. Individual sensors are connected in a closed system via a water and air line. As the host rock expands and contracts sensors are raised relative to another and water is displaced. The water level in each reservoir is sent to a computer in the mine and recorded. In order to measure the tilt of the rock between two points, the difference in water levels between adjacent sensors is computed. The difference between the end sensors is also calculated to determine the larger-scale tilt of the array. The tiltmeters in LaFarge mine are supported by concrete pedestals installed on the floor of the drift. In the Homestake mine the tiltmeters are placed on similar pedestals, as well as platforms made of artificial wood decking. These platforms are fixed to the wall of the drift with a rock bolt. Time and frequency domain analyses were performed on time series ranging from hours to six months to capture relevant time scales including the response to the 2010 Chile Earthquake (hour-long scale), the stages of the moon (month scale), Fox River floods (flooding week long scales and pressure dissipation month-long scales). By monitoring tiltmeter array responses to different forces, we aim at making predictions about the material properties of rock masses.

Roberts, J. S.; Wang, H. F.; Fratta, D.; Stetler, L. D.; Volk, J. T.; Geox^Tm

2010-12-01

252

Effects of soil data resolution on SWAT model stream flow and water quality predictions  

Microsoft Academic Search

The prediction accuracy of agricultural nonpoint source pollution models such as Soil and Water Assessment Tool (SWAT) depends on how well model input spatial parameters describe the characteristics of the watershed. The objective of this study was to assess the effects of different soil data resolutions on stream flow, sediment and nutrient predictions when used as input for SWAT. SWAT

Mengistu Geza; John E. McCray

2008-01-01

253

Prediction of the environmental concentration of pesticide in paddy field and surrounding surface water bodies  

Microsoft Academic Search

Pesticides are very important in European rice production. For appropriate environmental protection, it is useful to predict the potential impact of pesticides after application, in paddy fields, in paddy runoff, and in the surrounding water, by calculating predicted environmental concentrations (PECs). In this paper, a joint simulation is described, coupling a field-scale pesticide fate model (RICEWQ) and a transportation model

Zewei Miao; Laura Padovani; Carlo Riparbelli; Amy M. Ritter; Marco Trevisan; Ettore Capri

2003-01-01

254

A structural-feature-based computational approach for toxicity prediction of water-soluble arsenicals  

Microsoft Academic Search

We have used the density functional theory to make a toxicity prediction model of water-soluble arsenicals (WSA). The structures have been optimised for the minimum energy of the Schrödinger equation. In the present work, the usefulness of electrophilicity and charge transfer in predicting the toxicity of WSA, namely, monomethylarsenic acid (MMA) (III), dimethylarsenic acid (DMA) (III), arsenic acid, arsenous acid,

M. Abdus Salam; C. G. Jesudason; Keshav N. Shrivastava; M. Aminul Islam

2012-01-01

255

A structural-feature-based computational approach for toxicity prediction of water-soluble arsenicals  

Microsoft Academic Search

We have used the density functional theory to make a toxicity prediction model of water-soluble arsenicals (WSA). The structures have been optimised for the minimum energy of the Schrödinger equation. In the present work, the usefulness of electrophilicity and charge transfer in predicting the toxicity of WSA, namely, monomethylarsenic acid (MMA) (III), dimethylarsenic acid (DMA) (III), arsenic acid, arsenous acid,

M. Abdus Salam; C. G. Jesudason; Keshav N. Shrivastava; M. Aminul Islam

2011-01-01

256

Project Water Science. General Science High School Level.  

ERIC Educational Resources Information Center

This teacher's guide presents 12 hands-on laboratory activities for high school science classes that cover the environmental issue of water resources in California. The activities are separated into three sections. Five activities in the section on water quality address the topics of groundwater, water hardness, bottled water, water purity, and…

Water Education Foundation, Sacramento, CA.

257

Project Water Science. General Science High School Level.  

ERIC Educational Resources Information Center

|This teacher's guide presents 12 hands-on laboratory activities for high school science classes that cover the environmental issue of water resources in California. The activities are separated into three sections. Five activities in the section on water quality address the topics of groundwater, water hardness, bottled water, water purity, and…

Water Education Foundation, Sacramento, CA.

258

Water issues: the need for action at different levels  

Microsoft Academic Search

Fair fresh water distribution among humans and nature and among all sectors will be one of the main challenges of the 21st century. There is a complex interplay between the different water users, and clear systematics are needed for efficient decision making. Water uses can be divided into four sectors, (i) water for people, services and industries, (ii) water for

Alexander J. B. Zehnder; Hong Yang; Roland Schertenleib

2003-01-01

259

Predicting chlorine decay and THM formation in water supply systems  

Microsoft Academic Search

In 1976, the US Environmental Protection Agency (USEPA) published the results of a national survey that showed that chloroform\\u000a and other trihalomethanes (THMs) were ubiquitous in chlorinated drinking water. Also in 1976, the US National Cancer Institute\\u000a published results linking chloroform to cancer in laboratory animals, thus giving rise to an important public health issue.\\u000a Although numerous disinfection by-products (DBPs)

Daniel BrownJohn; John Bridgeman; John R. West

2011-01-01

260

Prediction of the octanol–water distribution of dithiocarbamate derivatives  

Microsoft Academic Search

Three different methodologies have been evaluated to estimate the octanol–water partition coefficient (Pow) of amphiphilic dithiocarbamates (DTC) (sodium salts of dithiocarbamic acids) with different substituents. The conventional shake-flask method has been used to measure Pow coefficients. This method gave good results for dithiocarbamates with short aliphatic substituents, but it presents difficulties for measuring Pow of DTC with long-chain substituents. The

I. Rogachev; C. Serra; A. Farran; J. L. Cortina; J. Gressel; A. Warshawsky

2003-01-01

261

Predicting the molecular shape of polysaccharides from dynamic interactions with water.  

PubMed

How simple monosaccharides, once polymerized, become the basis for structural materials remains a mystery. A framework is developed to investigate the role of water in the emergence of dynamic structure in polysaccharides, using the important beta(1-->4) linkage as an example. This linkage is studied within decasaccharide fragments of cellulose, chitin, mannan, xylan, and hyaluronan, using molecular simulations in the presence of explicit water solvent. Although cellulose, mannan, chitin, and xylan are chemically similar, their intramolecular hydrogen-bond dynamics and interaction with water are predicted to differ. Cellulose, mannan, and chitin favor relatively static intramolecular hydrogen bonds, xylan prefers dynamic water bridges, and multiple water configurations are predicted at the beta(1-->4) linkages of hyaluronan. With such a variety of predicted dynamics, the hypothesis that the beta(1-->4) linkage is stabilized by intramolecular hydrogen bonds was rejected. Instead, it is proposed that favored molecular configurations are consistent with maximum rotamer and water degrees of freedom, explaining observations made previously by X-ray diffraction. Furthermore, polysaccharides predicted to be conformationally restricted in simulations (cellulose, chitin, and mannan) prefer the solid state in reality, even as oligosaccharides. Those predicted to be more flexible (xylan and hyaluronan) are known to be soluble, even as high polymers. Therefore an intriguing correlation between chemical composition, water organization, polymer properties, and biological function is proposed. PMID:12626381

Almond, Andrew; Sheehan, John K

2002-12-17

262

The Relationship between Great Lakes Water Levels, Wave Energies, and Shoreline Damage  

Microsoft Academic Search

The latter half of the twentieth century can be characterized as a period of rising water levels on the Great Lakes, with record high levels in 1974 and 1986. Concurrent with these periods of high water level are reported periods of high shoreline damage and property loss. Water levels of the Great Lakes are determined by precipitation, evaporation, river outflow,

G. A. Meadows; L. A. Meadows; W. L. Wood; J. M. Hubertz; M. Perlin

1997-01-01

263

Derivation of a drinking water equivalent level (DWEL) related to the maximum contaminant level goal for perfluorooctanoic acid (PFOA), a persistent water soluble compound  

Microsoft Academic Search

Water soluble compounds persistent in humans and the environment pose a challenge for estimating safe levels in tap water. A viable approach to estimate a drinking water equivalent level (DWEL) for perfluorooctanoic acid (PFOA) was applied to its extensive relevant information from human and laboratory animal studies. PFOA has been identified at 3.5?g\\/L (mean) in tap water in proximity to

Robert G. Tardiff; M. Leigh Carson; Lisa M. Sweeney; Christopher R. Kirman; Yu-Mei Tan; Melvin Andersen; Christopher Bevan; Michael L. Gargas

2009-01-01

264

Shallow ground-water flow, water levels, and quality of water, 1980-84, Cowles Unit, Indiana Dunes National Lakeshore  

SciTech Connect

The Cowles Unit of Indiana Dunes National Lakeshore in Porter County, northwest Indiana, contains a broad dune-beach complex along the southern shoreline of Lake Michigan and a large wetland, called the Great Marsh, that occupies the lowland between the shoreline dunes and an older dune-beach complex farther inland. Water levels and water quality in the surficial aquifer were monitored from 1977 to 1984 near settling ponds on adjacent industrial property at the western end of the Cowles Unit. Since 1980, when the settling pond bottoms were sealed, these intradunal lowlands contained standing water only during periods of high snowmelt or rainfall. Water level declines following the cessation of seepage ranged from 6 feet at the eastern-most settling pond to nearly 14 feet at the western-most pond. No general pattern of water table decline was observed in the Great Marsh or in the shoreline dune complex at distances > 3,000 ft east or north of the settling ponds. Since the settling ponds were sealed, the concentration of boron has decreased while concentrations of cadmium, arsenic, zinc, and molybdenum in shallow ground-water downgradient of the ponds show no definite trends in time. Arsenic, boron and molybdenum have remained at concentrations above those of shallow groundwater in areas unaffected by settling pond seepage. 11 refs., 10 figs., 1 tab.

Cohen, D.A.; Shedlock, R.J.

1986-01-01

265

Serum VEGF levels as predictive marker of bisphosphonate-related osteonecrosis of the jaw  

PubMed Central

Recent studies have been reported that angiogenesis suppression may play a role in developing bisphosphonate-related osteonecrosis of the jaw (B-ONJ). According to these evidence we evaluated the role of VEGF as predictive marker of B-ONJ onset. Of the 81 patients, 6 developed B-ONJ following bisphosphonate treatment. These patients showed a strongest decrease in VEGF circulating levels at day 7 and at day 21 after the first administration. These data demonstrated for the first time that the anti-angiogenic properties of bisphosphonates are directly linked to B-ONJ pathogenesis and serum VEGF levels could represent an effective early predictive marker.

2012-01-01

266

A predictive theory of intentions to exit street-level prostitution.  

PubMed

Street-level prostitution is notoriously difficult to escape and rarely do women exit prostitution on their first attempt or without experiencing serious negative consequences to their physical or mental health. Unfortunately, few theories exist that explain the exiting process and those that do exist are difficult to test quantitatively. This article applies the integrative model of behavioral prediction to examine intentions to exit prostitution through attitudes, norms, and self-efficacy beliefs that underlie a woman's intention to exit prostitution. Constructs unique prostitution--agency and societal context--enhance the model. This theory may explain and predict an exit from street-level prostitution. PMID:23136182

Cimino, Andrea N

2012-10-01

267

Using hyperspectral imagery to predict post-wildfire soil water repellency  

Microsoft Academic Search

A principal task of evaluating large wildfires is to assess fire's effect on the soil in order to predict the potential watershed response. Two types of soil water repellency tests, the water drop penetration time (WDPT) test and the mini-disk infiltrometer (MDI) test, were performed after the Hayman Fire in Colorado, in the summer of 2002 to assess the infiltration

Sarah A. Lewis; Peter R. Robichaud; Bruce E. Frazier; Joan Q. Wu; Denise Y. M. Laes

2008-01-01

268

USING ENSEMBLE STREAMFLOW PREDICTION FOR WATER SUPPLY FORECASTING IN BRITISH COLUMBIA - PRACTICALITIES AND PITFALLS  

Microsoft Academic Search

BC Hydro has just completed new watershed model calibrations for 20 of its reservoirs, which would enable the use of Ensemble Streamflow Prediction (ESP) techniques for preparing water supply forecasts. ESP methods have been used to forecast the seasonal water supply for BC Hydro's large interior snow-driven basins for a number of years with much success. But using the technique

Stephanie Smith; Frank Weber

269

Water Consumption Prediction of Istanbul City by Using Fuzzy Logic Approach  

Microsoft Academic Search

This paper presents a Takagi Sugeno (TS) fuzzy method for predicting future monthly water consumption values from three antecedent water consumption amounts, which are considered as independent variables. Mean square error (MSE) values for different model configurations are obtained, and the most effective model is selected. It is expected that this model will be more extensively used than Markov or

Abdüsselam Altunkaynak; Mehmet Özger; Mehmet Çakmakci

2005-01-01

270

Predicting effects of global climate change on reservoir water quality and fish habitat  

Microsoft Academic Search

This paper demonstrates the use of general circulation models (GCMs) for assessing global climate change effects on reservoir water quality and illustrates that general conclusions about the effects of increased carbon dioxide (COâ) concentrations on water resources can be made by using GCMs. These conclusions are based on GCM predictions of the climatic effects of doubling COâ concentrations (the 2

L. H. Chang; S. F. Railsback

1989-01-01

271

Dual Purpose Gamma Thermometer for Use as a Reactor Power Level and Core Coolant Level Detector for Pressurized Water Reactors.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A modified gamma thermometer has been studied for use in a pressurized water reactor as a local power level detector and core coolant level detector. Utilization of ...

1982-01-01

272

Predicting the Health of a Natural Water System  

ERIC Educational Resources Information Center

|This project was developed as an interdisciplinary application of the optimization of a single-variable function. It was used in a freshman-level single-variable calculus course. After the first month of the course, students had been exposed to the concepts of the derivative as a rate of change, average and instantaneous velocities, derivatives…

Graves, Gregory H.

2010-01-01

273

[Analysis of pollution levels of 16 antibiotics in the river water of Daliao River water system].  

PubMed

The detection of the pollution level of antibiotics in Daliao River system is a meaningful work. Sixteen antibiotics (6 sulfonamides, 5 fluoroquinolones, 3 tetracyclines and 2 chloramphenicols) were simultaneously quantified with solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the SPE procedure, methanol and 2% (v/v) ammonia/methanol were used as the elution solvents in sequence to reduce the elution volume and improve the recovery. The results showed that this method have good sensitivity and enrichment effect for the target antibiotics in aqueous water, the recoveries ranged from 69.5% to 122.6%, the detection limits ranged from 0.05 ng/L to 0.32 ng/L. Thirteen antibiotics were found in the river water of Daliao River water system. Sulfa antibiotics were widely distributed, in which sulfamethoxazole was detected in all the sampling sites. The concentration of fluoroquinolones was relatively high in some sampling sites. The highest detection concentration of enoxacin was 41.3 ng/L. The frequencies and concentrations of tetracyclines and chloramphenicols were lower. In the upper reaches of the river, the concentrations of the 4 types of antibiotics appeared lower, but around the large cities such as Shenyang City, Benxi City, Liaoyang City, the concentrations showed higher levels. The study indicated that the Daliao River water system suffered from the pollution of antibiotics to a certain extent. PMID:23256376

Yang, Changqing; Wang, Longxing; Hou, Xiaohong; Chen, Jiping

2012-08-01

274

Determination of trace level perchlorate in drinking water and ground water by ion chromatography.  

PubMed

Ammonium perchlorate, a key ingredient in solid rocket propellants, has recently been found in ground and surface waters in the USA in a number of states, including California, Nevada, Utah, and West Virginia. Perchlorate poses a health risk and preliminary data from the US Environmental Protection Agency reports that exposure to less than 4-18 micrograms/l provides adequate human health protection. An ion chromatographic method was developed for the determination of low microgram/l levels of perchlorate in drinking and ground waters based on a Dionex IonPac AS11 column, a 100 mM hydroxide eluent, large loop (1000 microliters) injection, and suppressed conductivity detection. The method is free of interferences from common anions, linear in the range of 2.5-100 micrograms/l, and quantitative recoveries were obtained for low microgram/l levels of perchlorate in spiked drinking and ground water samples. The method detection limit of 0.3 microgram/l permits quantification of perchlorate below the levels which ensure adequate health protection. A new polarizable anion analysis column, the IonPac AS16, and its potential applicability for this analysis is also discussed. PMID:10457473

Jackson, P E; Laikhtman, M; Rohrer, J S

1999-07-30

275

Numerical Weather Prediction and Earth System Prediction to Better Understand Sea Level Rise/Coastal Issues as They Affect Readiness.  

National Technical Information Service (NTIS)

The National Unified Operational Prediction Capability (NUOPC) is a joint effort between NOAA and DoD to improve collaboration and accelerate operational numerical weather prediction. The Earth System Prediction Capability (ESPC) expands this collaboratio...

D. McCarren

2011-01-01

276

Subsampling Approach to Aggregating LiDAR-Derived Forest Structure Predictions to the Forest Stand Level  

NASA Astrophysics Data System (ADS)

LiDAR remote sensing is a powerful resource for modeling forest structure. However, many of the relationships between forest structure and LiDAR are investigated at a plot level, limiting stand level inferences. Landscape- level LiDAR predictions often produce huge volumes of estimated data thus making model validation problematic. Presented is a method for generating a random sample of subplots and aggregating subplot model predictions to the stand level. Based on the autocorrelation of basal area at the landscape-level, we assessed the optimal number of subsamples needed to capture within stand variability, comparable to thresholds used in stand exams. RANDOM FOREST was used to model relationships between LiDAR and field measured basal area then apply an estimate to the subplots. Using subplot estimates, mean and variance of basal area was calculated within each stand, creating an aggregated stand estimate and an indication of the variation in basal area. Results demonstrate that predictions applied to stand subplots can be used to confidently summarize information at the stand level and provide a controllable sample for model validation. We conclude that LiDAR surveys in association with appropriately designed ground validation plots could augment or largely replace traditional stand exams, for the benefit of forest landscape managers.

Evans, J. S.; Hudak, A. T.

2006-12-01

277

Mechanical Complications after Myocardial Infarction Reliably Predicted Using C-Reactive Protein Levels and Lymphocytopenia  

Microsoft Academic Search

We assessed the accuracy of C-reactive protein (CRP) levels and lymphocyte counts to predict a mechanical complication (MC) after myocardial infarction (MI). Within 10 years, we identified 36 patients with 39 echocardiographically confirmed MC within 30 days of MI: ventricular septal defect (17 cases), papillary muscle rupture (10 cases), and left ventricular free wall rupture (12 cases). They were compared

Anouk Widmer; André Z. Linka; Christine H. Attenhofer Jost; Barbara Buergi; Hans Peter Brunner-La Rocca; Franco Salomon; Burkhardt Seifert; Rolf Jenni

2003-01-01

278

A postgenomic method for predicting essential genes at subsaturation levels of mutagenesis: Application to Mycobacterium tuberculosis  

Microsoft Academic Search

We describe a postgenomic in silico approach for identifying genes that are likely to be essential and estimate their proportion in haploid genomes. With the knowledge of all sites eligible for mutagenesis and an experimentally determined partial list of nonessential genes from genome mutagenesis, a Bayesian statistical method provides reasonable predictions of essential genes with a subsaturation level of random

Gyanu Lamichhane; Matteo Zignol; Natalie J. Blades; Deborah E. Geiman; Annette Dougherty; Jacques Grosset; Karl W. Broman; William R. Bishai

2003-01-01

279

Low leptin levels predict amenorrhea in underweight and eating disordered females  

Microsoft Academic Search

Evidence that leptin plays an important role in reproductive function is accumulating rapidly. We hypothesized that low leptin synthesis is associated with amenorrhea. We therefore determined serum leptin levels in 43 underweight female students, who were screened for lifetime occurrence of amenorrhea. We assessed the predictive value of leptin, body mass index (BMI), fat mass and percent body fat, respectively,

W Köpp; W F Blum; S von Prittwitz; A Ziegler; H Lübbert; G Emons; W Herzog; S Herpertz; H-C Deter; H Remschmidt; J Hebebrand

1997-01-01

280

Prediction of county-level cancer incidence rates and counts in the United States  

Cancer.gov

March 28, 2012 1:30 PM - 2:30 PM + Add to Outlook Calendar Speaker Binbing Yu, PhDChief, Biometry SectionLaboratory of Epidemiology, Demography, and BiometryNational Institute on Aging (NIA) Topic Prediction of county-level cancer incidence rates and

281

Artificial Neural Network Prediction of Amino Acid Levels In Feed Ingredients  

Microsoft Academic Search

Artificial Neural Networks (ANN), which are biologically inspired tools, serve as an alternative to regression analysis for complex data. Based on CP or proximate analysis (PA) of ingredients, two types of ANN and linear regression (LR) were evaluated for predicting amino acid levels in corn, wheat, soybean meal, meat and bone meal, and fish meal. The two ANN were a

WILLIAM B. ROUSH; TERRI L. CRAVENER

282

Retail sales prediction and item recommendations using customer demographics at store level  

Microsoft Academic Search

This paper outlines a retail sales prediction and product recommendation system that was implemented for a chain of retail stores. The relative importance of consumer demographic characteristics for accurately modeling the sales of each customer type are derived and implemented in the model. Data consisted of daily sales information for 600 products at the store level, broken out over a

Michael Giering

2008-01-01

283

On the prediction of wayside noise levels for high-speed railway vehicles  

Microsoft Academic Search

The relative contributions of aerodynamic and wheel\\/rail noise to railway wayside noise levels are not well understood. Methods for predicting these contributions discussed in this paper include an equation for turbulent boundary layer noise (the minimum wayside noise), an empirical formula for total aerodynamic noise based on airframe noise studies, and the Peters equation for wheel\\/rail interaction noise. Comparisons are

W. F. King III

1976-01-01

284

Tissue spectrophotometry and thermographic imaging applied to routine clinical prediction of amputation level viability  

Microsoft Academic Search

About 5% of British males over 50 years develop peripheral arterial occlusive disease. Of these about 2% ultimately require lower limb amputation. In 1995 we proposed a new technique using lightguide spectrophotometry to measure the oxygen saturation level of haemoglobin (SO2) in the skin as a method for predicting tissue viability. This technique, in combination with thermographic imaging, was compared

Jon M. Hanson; David K. Harrison; Ian E. Hawthorn

2002-01-01

285

The Impact of Java Applications at Microarchitectural Level from Branch Prediction Perspective  

Microsoft Academic Search

The portability, the object-oriented and distributed programming mod- els, multithreading support and automatic garbage collection are features that make Java very attractive for application developers. The main goal of this paper consists in pointing out the impact of Java applications at microarchitectural level from two perspectives: unbiased branches and indirect jumps\\/calls, such branches limiting the ceiling of dynamic branch prediction

Adrian Florea; Arpad Gellert; Lucian Vintan; Marius Veltan

286

Protein C concentrations in severe sepsis: an early directional change in plasma levels predicts outcome  

Microsoft Academic Search

INTRODUCTION: Protein C, because of its central role in hemostasis, plays an integral role in the host response to infection. Protein C depletion, resulting from increased consumption, degradation, and\\/or decreased synthesis, is characteristic of sepsis and has been shown to predict morbidity and mortality. The objective of this study was to determine whether early directional changes in protein C levels

Andrew F Shorr; Gordon R Bernard; Jean-Francois Dhainaut; James R Russell; William L Macias; David R Nelson; David P Sundin

2006-01-01

287

Increased Circulating Levels of Natriuretic Peptides Predict Future Cardiac Event in Patients with Chronic Hemodialysis  

Microsoft Academic Search

Background\\/Aim: Cardiovascular events are the major determinant of the prognosis in patients with chronic hemodialysis. The present study was designed to investigate whether increased plasma levels of atrial or brain natriuretic peptides (ANP or BNP) predict future cardiac events in such patients. Methods: Fifty-three patients undergoing chronic hemodialysis without clinical symptoms suggestive of cardiac disorders were enrolled and their blood

Takatoshi Goto; Hiroyuki Takase; Takayuki Toriyama; Tomonori Sugiura; Yutaka Kurita; Nobuo Tsuru; Hiroaki Masuda; Kunihiko Hayashi; Ryuzo Ueda; Yasuaki Dohi

2002-01-01

288

Involving regional expertise in nationwide modeling for adequate prediction of climate change effects on different demands for fresh water  

NASA Astrophysics Data System (ADS)

Nationwide modeling aims to produce a balanced distribution of climate change effects (e.g. harm on crops) and possible compensation (e.g. volume fresh water) based on consistent calculation. The present work is based on the Netherlands Hydrological Instrument (NHI, www.nhi.nu), which is a national, integrated, hydrological model that simulates distribution, flow and storage of all water in the surface water and groundwater systems. The instrument is developed to assess the impact on water use on land-surface (sprinkling crops, drinking water) and in surface water (navigation, cooling). The regional expertise involved in the development of NHI come from all parties involved in the use, production and management of water, such as waterboards, drinking water supply companies, provinces, ngo's, and so on. Adequate prediction implies that the model computes changes in the order of magnitude that is relevant to the effects. In scenarios related to drought, adequate prediction applies to the water demand and the hydrological effects during average, dry, very dry and extremely dry periods. The NHI acts as a part of the so-called Deltamodel (www.deltamodel.nl), which aims to predict effects and compensating measures of climate change both on safety against flooding and on water shortage during drought. To assess the effects, a limited number of well-defined scenarios is used within the Deltamodel. The effects on demand of fresh water consist of an increase of the demand e.g. for surface water level control to prevent dike burst, for flushing salt in ditches, for sprinkling of crops, for preserving wet nature and so on. Many of the effects are dealt with? by regional and local parties. Therefore, these parties have large interest in the outcome of the scenario analyses. They are participating in the assessment of the NHI previous to the start of the analyses. Regional expertise is welcomed in the calibration phase of NHI. It aims to reduce uncertainties by improving the rules for manmade re-direction of surface water, schematizations & parameters included in the model. This is carried out in workshops and in one-to-one expert meetings on regional models & the NHI. All results of NHI are presented on the internet and any expert may suggest improvements to the model. The final goal of the involvement of regional parties is the acceptation by decision impact receiving authorities

de Lange, Wim; Prinsen, Geert.; Hoogewoud, Jacco; Veldhuizen, Ab; Ruijgh, Erik; Kroon, Timo

2013-04-01

289

Prediction of 1-octanol–water partition coefficient and infinite dilution activity coefficient in water from the PR + COSMOSAC model  

Microsoft Academic Search

The Peng–Robinson equation of state (PR EOS) is used for the prediction of 1-octanol–water partition coefficients (KOW) and infinite dilution activity coefficients (??). Unlike the conventional approach where the EOS parameters must be determined from the critical properties and acentric factor of each chemical species in addition to using some mixing rule to account for composition dependence, these parameters are

Chieh-Ming Hsieh; Shiang-Tai Lin

2009-01-01

290

Predicting water’s phase diagram and liquid-state anomalies  

Microsoft Academic Search

Water expands upon freezing, has minima in its volume, heat capacity, and isothermal compressibility with temperature, and shows signs of a first-order phase transition when supercooled. We present an analytical molecular theory that can account for these behaviors. It suggests that local network formation and hydrogen-bonding cooperativity between triplets of neighboring molecules are keys to understanding water’s thermodynamics.

Thomas M. Truskett; Ken A. Dill

2002-01-01

291

Non-cholesterol sterol levels predict hyperglycemia and conversion to type 2 diabetes in Finnish men.  

PubMed

We investigated the levels of non-cholesterol sterols as predictors for the development of hyperglycemia (an increase in the glucose area under the curve in an oral glucose tolerance test) and incident type 2 diabetes in a 5-year follow-up study of a population-based cohort of Finnish men (METSIM Study, N?=?1,050) having non-cholesterol sterols measured at baseline. Additionally we determined the association of 538,265 single nucleotide polymorphisms (SNP) with non-cholesterol sterol levels in a cross-sectional cohort of non-diabetic offspring of type 2 diabetes (the Kuopio cohort of the EUGENE2 Study, N?=?273). We found that in a cross-sectional METSIM Study the levels of sterols indicating cholesterol absorption were reduced as a function of increasing fasting glucose levels, whereas the levels of sterols indicating cholesterol synthesis were increased as a function of increasing 2-hour glucose levels. A cholesterol synthesis marker desmosterol significantly predicted an increase, and two absorption markers (campesterol and avenasterol) a decrease in the risk of hyperglycemia and incident type 2 diabetes in a 5-year follow-up of the METSIM cohort, mainly attributable to insulin sensitivity. A SNP of ABCG8 was associated with fasting plasma glucose levels in a cross-sectional study but did not predict hyperglycemia or incident type 2 diabetes. In conclusion, the levels of some, but not all non-cholesterol sterols are markers of the worsening of hyperglycemia and type 2 diabetes. PMID:23840693

Cederberg, Henna; Gylling, Helena; Miettinen, Tatu A; Paananen, Jussi; Vangipurapu, Jagadish; Pihlajamäki, Jussi; Kuulasmaa, Teemu; Stan?áková, Alena; Smith, Ulf; Kuusisto, Johanna; Laakso, Markku

2013-06-28

292

Predicting inhomogeneous water absorption in an ionic diblock polymer membrane  

NASA Astrophysics Data System (ADS)

Fuel cells convert fuel directly into electrical power. Their performance depends on a permeable (yet strong) membrane to allow ion conduction (while preventing combustion). Anion-exchange membrane fuel-cells are especially economical to produce, but technological hurdles currently limit durability and OH^- conductivity of the membrane. One solution to these problems is a diblock morphology. Layers of stiff hydrophobic polymer provide structure, while interspersed layers of polyelectrolyte provide avenues for conduction. Previously, little was known about the structure within the conducting layer. We adapted Scheutjens-Fleer polymer-brush theory to a lamellar geometry. The calculation tells where the polyelectrolytes congregate within a lamella, and hence how conduction occurs. This talk focuses on a new diblock material, PMB-PVBTMA. We show how the features of the material determine the intra-lamellar structure. We conclude that at low humidity, the bulkiness of PVBTMA causes it to adopt a near-uniform distribution within the conducting block. At high humidity, however, a phase separation may induce abrupt water channels. Understanding the architecture within the conducting layer will help guide research into better anion-exchange membranes materials.

Herbst, Daniel; Witten, Thomas

2013-03-01

293

Simulated effect of vadose infiltration on water levels in the Northern Guam Lens Aquifer  

Microsoft Academic Search

Regional-scale hydrology of the fresh water lens in the Northern Guam Lens Aquifer has been simulated in the past using a finite element, sharp interface computer model, SWIG2D. Systematic differences exist between observed and computed water levels. Computed seasonal peak water levels are higher, and the computed seasonal lows are lower than the respective observed levels. It is hypothesized that

D. N Contractor; J. W Jenson

2000-01-01

294

Water-Level Responses to Barometric-Pressure Fluctuations in Wells in Semi-Confined Aquifers  

Microsoft Academic Search

Hydrologists have long recognized that changes in barometric pressure can produce changes in water levels in wells. The relationship between barometric pressure and water level has traditionally been characterized using the barometric efficiency (BE), the ratio of the change in water level to the change in barometric pressure head. Although BE has proven to be an effective means of characterizing

W. Jin; J. J. Butler

2009-01-01

295

Estimating Impaired Waters on a County Level for Public Health Analysis  

EPA Science Inventory

Assessing the population-level impact of water quality on health can be difficult. Water quality data are measured at a watershed level and health data are organized at different levels of aggregation. To address this discrepancy and enable the consideration of water quality for ...

296

Impacts at the coast: Climate change influences on Lake Huron's water levels at Oliphant (Ontario)  

Microsoft Academic Search

Since 1998, climate change induced low water levels in the Great Lakes have caused environmental and socioeconomic impacts along most of the Great Lakes' shorelines. According to recent climate change research involving different water level scenarios, climate change over the next century may continue to cause water levels in the Great Lakes to decline. Such impacts may include wider shorelines,

Kevin Tupman

2004-01-01

297

Scaling Analysis of Water Level Records from the North American Great Lakes  

Microsoft Academic Search

The Great Lakes hydrologic cycle is responsible for the water levels in the Great Lakes. Precipitation, runoff, snowmelt, retention time, evaporation, and outflow all contribute to water levels observed in the Great Lakes. Verified hourly water level data for five stations in Lake Michigan and four stations in Lake Superior were obtained from NOAA and examined. For each station, the

J. Smigelski; S. F. Tebbens; C. C. Barton

2005-01-01

298

Prediction of Air and Water Film Coefficients in Cooling Towers from Penetration Theory  

NASA Astrophysics Data System (ADS)

In the experimental analysis of cooling towers, it is not necessarily easy to obtain the values of air and water phase film volumetric coefficients, because the experimental conditions are limited to which the Mickley's graphical method is applicable. The purpose of this study is to predict the individual coefficients using more practical method based on the penetration theory for water film. The tower used in this study is of a commercial induced draft counterflow type. Water-cooling experiments were made with constantly designed air and water flow rates and with varied water temperatures. Then, we attempted to predict the individual coefficients from these over-all results by means of the reported procedure. Finally, applying our method to the similar experimental date of other workers, we obtained nearly equal results compared with the Mickley's method.

Yazaki, Yoshimu; Yoshioka, Hideaki

299

Farm-level and district efforts to improve water management during drought  

Microsoft Academic Search

The fifth year of drought in California brought reductions in surface water deliveries to many water districts. In the central San Joaquin Valley, water deliveries to Broadview Water District were reduced by 50% in 1990 and by 75% in 1991. The district increased the level of service provided to farmers during these years by providing accurate water use data, increasing

Dennis Wichelns; David Cone

1992-01-01

300

Lake-level Variability and Water Availability in the Great Lakes  

Microsoft Academic Search

Key components of water availability in a hydrologic system4 are the amount of water in storage and the variability of that amount. In the Great Lakes Basin, a vast amount of water is stored in the lakes themselves. Because of the lakes’ size, small changes in water levels cause huge changes in the amount of water in storage. Approximately 5,439

Douglas A. Wilcox; Todd A. Thompson; Robert K. Booth; J. R. Nicholas

2007-01-01

301

Effects of soil data resolution on SWAT model stream flow and water quality predictions.  

PubMed

The prediction accuracy of agricultural nonpoint source pollution models such as Soil and Water Assessment Tool (SWAT) depends on how well model input spatial parameters describe the characteristics of the watershed. The objective of this study was to assess the effects of different soil data resolutions on stream flow, sediment and nutrient predictions when used as input for SWAT. SWAT model predictions were compared for the two US Department of Agriculture soil databases with different resolution, namely the State Soil Geographic database (STATSGO) and the Soil Survey Geographic database (SSURGO). Same number of sub-basins was used in the watershed delineation. However, the number of HRUs generated when STATSGO and SSURGO soil data were used is 261 and 1301, respectively. SSURGO, with the highest spatial resolution, has 51 unique soil types in the watershed distributed in 1301 HRUs, while STATSGO has only three distributed in 261 HRUS. As a result of low resolution STATSGO assigns a single classification to areas that may have different soil types if SSURGO were used. SSURGO included Hydrologic Response Units (HRUs) with soil types that were generalized to one soil group in STATSGO. The difference in the number and size of HRUs also has an effect on sediment yield parameters (slope and slope length). Thus, as a result of the discrepancies in soil type and size of HRUs stream flow predicted was higher when SSURGO was used compared to STATSGO. SSURGO predicted less stream loading than STATSGO in terms of sediment and sediment-attached nutrients components, and vice versa for dissolved nutrients. When compared to mean daily measured flow, STATSGO performed better relative to SSURGO before calibration. SSURGO provided better results after calibration as evaluated by R(2) value (0.74 compared to 0.61 for STATSGO) and the Nash-Sutcliffe coefficient of Efficiency (NSE) values (0.70 and 0.61 for SSURGO and STATSGO, respectively) although both are in the same satisfactory range. Modelers need to weigh the benefits before selecting the type of data resolution they are going to use depending on the watershed size and level of accuracy required because more effort is required to prepare and calibrate the model when a fine resolution soil data is used. PMID:17475392

Geza, Mengistu; McCray, John E

2007-05-01

302

Water levels in wells J-11 and J-12, 1989-91, Yucca Mountain Area, Nevada  

SciTech Connect

Water levels have been measured in the Yucca Mountain area, Nevada, since 1981 in order to gain a better understanding of the ground-water flow system in the area. Water levels in wells J-11 and J-12 have been periodically measured using calibrated reeled steel tapes since 1989, however, calculation of water-level altitude was not possible prior to 1993 due to missing reference elevations. These elevations were determined in 1993 by the U.S. Geological Survey. During 1989-91, water-level altitudes for well J-11 ranged from 732.09 to 732.40 meters and the mean water-level altitude was 732.19 meters. During 1989-91, water-level altitudes for well J-12 ranged from 727.84 to 728.03 meters, and the mean water-level altitude was 727.95 meters.

Boucher, M.S.

1994-12-31

303

Water levels in wells J-11 and J-12, 1989-91, Yucca Mountain area, Nevada  

USGS Publications Warehouse

Water levels have been measured in the Yucca Mountain area, Nevada, since 1981 in order to gain a better understanding of the gound-water flow system in the area. Water level in wells J-11 and J-12 have been periodically measured using calibrated reeled steel tapes since 1989, however, calculation of water-level altitude was not possible prior to 1993 due to missing reference elevations. These elevations were determined in 1993 by the U.S. Geological Survey. During 1989-91, water-level altitudes for well J-11 ranged from 732.09 to 732.40 meters and the mean water-level altitude was 732.19 meters. During 1989-91, water-level altitudes for well J-12 ranged from 727.84 to 728.03 meters, and the mean water-level altitude was 727.95 meters.

Boucher, Michelle S.

1994-01-01

304

Predicting Land-Ice Retreat and Sea-Level Rise with the Community Earth System Model  

SciTech Connect

Coastal stakeholders need defensible predictions of 21st century sea-level rise (SLR). IPCC assessments suggest 21st century SLR of {approx}0.5 m under aggressive emission scenarios. Semi-empirical models project SLR of {approx}1 m or more by 2100. Although some sea-level contributions are fairly well constrained by models, others are highly uncertain. Recent studies suggest a potential large contribution ({approx}0.5 m/century) from the marine-based West Antarctic Ice Sheet, linked to changes in Southern Ocean wind stress. To assess the likelihood of fast retreat of marine ice sheets, we need coupled ice-sheet/ocean models that do not yet exist (but are well under way). CESM is uniquely positioned to provide integrated, physics based sea-level predictions.

Lipscomb, William [Los Alamos National Laboratory

2012-06-19

305

Investigations on boron levels in drinking water sources in China  

Microsoft Academic Search

To evaluate boron contamination of public drinking water in China, both dissolved and total boron contents in 98 public drinking\\u000a water sources from 49 cities, 42 brands of bottled water samples from supermarkets in several cities, and 58 water samples\\u000a from boron industrial area were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Our experimental results\\u000a showed that boron existed in

Ren-ji Xu; Xiao-ru Xing; Qun-fang Zhou; Gui-bin Jiang; Fu-sheng Wei

2010-01-01

306

Prediction of contaminant fate and transport in potable water systems using H2OFate  

NASA Astrophysics Data System (ADS)

BlazeTech has recently developed a software called H2OFate to predict the fate and transport of chemical and biological contaminants in water distribution systems. This software includes models for the reactions of these contaminants with residual disinfectant in bulk water and at the pipe wall, and their adhesion/reactions with the pipe walls. This software can be interfaced with sensors through SCADA systems to monitor water distribution networks for contamination events and activate countermeasures, as needed. This paper presents results from parametric calculations carried out using H2OFate for a simulated contaminant release into a sample water distribution network.

Devarakonda, Venkat; Manickavasagam, Sivakumar; Vanblaricum, Vicki; Ginsberg, Mark

2009-05-01

307

Root water uptake and transport: using physiological processes in global predictions.  

PubMed

Plant water loss, regulated by stomata and driven by atmospheric demand, cannot exceed the maximum steady-state supply through roots. Just as an electric circuit breaks when carrying excess current, the soil-plant continuum breaks if forced to transport water beyond its capacity. Exciting new molecular, biophysical and ecological research suggests that roots are the weakest link along this hydraulic flow path. We attempt here to predict rooting depth and water uptake using the hydraulic properties of plants and the soil, and also to suggest how new physiological tools might contribute to larger-scale studies of hydraulic lift, the water balance and biosphere-atmosphere interactions. PMID:11077257

Jackson, R B; Sperry, J S; Dawson, T E

2000-11-01

308

Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method  

SciTech Connect

A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using the described method, the predicted water vapor transport rate (WVTR) for a parenteral solution packaged in PVC is in reasonable agreement with actual WVTR as determined by weight loss under precisely controlled conditions.

Wood, R.W.; Mulski, M.J.; Kuu, W.Y. (Baxter Healthcare Corporation, Round Lake, IL (USA))

1990-09-01

309

Distinct coping strategies differentially predict urge levels and lapses in a smoking cessation attempt.  

PubMed

This study analysed mechanisms through which stress-coping and temptation-coping strategies were associated with lapses. Furthermore, we explored whether distinct coping strategies differentially predicted reduced lapse risk, lower urge levels, or a weaker association between urge levels and lapses during the first week of an unassisted smoking cessation attempt. Participants were recruited via the internet and mass media in Switzerland. Ecological momentary assessment (EMA) with mobile devices was used to assess urge levels and lapses. Online questionnaires were used to measure smoking behaviours and coping variables at baseline, as well as smoking behaviour at the three-month follow-up. The sample consisted of 243 individuals, aged 20 to 40, who reported 4199 observations. Findings of multilevel regression analyses show that coping was mainly associated with a reduced lapse risk and not with lower urge levels or a weaker association between urge levels and lapses. 'Calming down' and 'commitment to change' predicted a lower lapse risk and also a weaker relation between urge levels and lapses. 'Stimulus control' predicted a lower lapse risk and lower urge levels. Conversely, 'task-orientation' and 'risk assessment' were related to higher lapse risk and 'risk assessment' also to higher urge levels. Disengagement coping i.e. 'eating or shopping', 'distraction', and 'mobilising social support' did not affect lapse risk. Promising coping strategies during the initial stage of smoking cessation attempt are targeted directly at reducing the lapse risk and are characterised by engagement with the stressor or one's reactions towards the stressor and a focus on positive consequences instead of health risks. PMID:23501139

Brodbeck, Jeannette; Bachmann, Monica S; Znoj, Hansjörg

2013-02-16

310

U.S. Geological Survey Water science strategy--observing, understanding, predicting, and delivering water science to the nation  

USGS Publications Warehouse

This report expands the Water Science Strategy that began with the USGS Science Strategy, “Facing Tomorrow’s Challenges—U.S. Geological Survey Science in the Decade 2007–2017” (U.S. Geological Survey, 2007). This report looks at the relevant issues facing society and develops a strategy built around observing, understanding, predicting, and delivering water science for the next 5 to 10 years by building new capabilities, tools, and delivery systems to meet the Nation’s water-resource needs. This report begins by presenting the vision of water science for the USGS and the societal issues that are influenced by, and in turn influence, the water resources of our Nation. The essence of the Water Science Strategy is built on the concept of “water availability,” defined as spatial and temporal distribution of water quantity and quality, as related to human and ecosystem needs, as affected by human and natural influences. The report also describes the core capabilities of the USGS in water science—the strengths, partnerships, and science integrity that the USGS has built over its 134-year history. Nine priority actions are presented in the report, which combine and elevate the numerous specific strategic actions listed throughout the report. Priority actions were developed as a means of providing the audience of this report with a list for focused attention, even if resources and time limit the ability of managers to address all of the strategic actions in the report.

Evenson, Eric J.; Orndorff, Randall C.; Blome, Charles D.; Böhlke, John Karl; Hershberger, Paul K.; Langenheim, Victoria E.; McCabe, Gregory J.; Morlock, Scott E.; Reeves, Howard W.; Verdin, James P.; Weyers, Holly S.; Wood, Tamara M.

2013-01-01

311

Projecting groundwater arsenic levels to define water use options in South Asia (Invited)  

NASA Astrophysics Data System (ADS)

More than a hundred million people are at risk of exposure to dangerous levels of geogenic arsenic in drinking water across South Asia. Arsenic within rocks of the Himalayas is liberated to the sediment load of the major river systems draining these mountain systems through erosion and ultimately deposited within the massive deltas of South Asia. Upon burial, arsenic may be released to the aqueous phase through microbially driven reduction of arsenic and iron, leading to contamination of groundwater now commonly used for human consumption. Fueling this process is organic carbon that stimulates microbial activity and, with limited oxygen supply, anaerobic metabolisms. Resulting concentrations of arsenic, however, are distributed unevenly in the subsurface as a result of heterogeneity in groundwater flow and biogeochemical processes. While such heterogeneity make predicting groundwater arsenic concentrations difficult both spatially and temporally, it provides an opportunity to potentially extract water safe (or safer) for human consumption. Here we describe the fate controlling processes of arsenic with a coupled biogeochemical-hydrologic model for the Mekong Delta and illustrate changes in groundwater quality with land use alterations—a key driver in determining long-term temporal variation in arsenic distribution. For areas where low-arsenic groundwater is not available, we further examine possible solutions, including alternate water resources, for providing safe drinking water to the local populous.

Fendorf, S.; Kocar, B. D.; Polizzotto, M.; Stuckey, J.; Benner, S. G.

2010-12-01

312

Growth and food consumption by tiger muskellunge: Effects of temperature and ration level on bioenergetic model predictions  

USGS Publications Warehouse

We measured growth of age-0 tiger muskellunge as a function of ration size (25, 50, 75, and 100% C(max))and water temperature (7.5-25??C) and compared experimental results with those predicted from a bioenergetic model. Discrepancies between actual and predicted values varied appreciably with water temperature and growth rate. On average, model output overestimated winter consumption rates at 10 and 7.5??C by 113 to 328%, respectively, whereas model predictions in summer and autumn (20-25??C) were in better agreement with actual values (4 to 58%). We postulate that variation in model performance was related to seasonal changes in esocid metabolic rate, which were not accounted for in the bioenergetic model. Moreover, accuracy of model output varied with feeding and growth rate of tiger muskellunge. The model performed poorly for fish fed low rations compared with estimates based on fish fed ad libitum rations and was attributed, in part, to the influence of growth rate on the accuracy of bioenergetic predictions. Based on modeling simulations, we found that errors associated with bioenergetic parameters had more influence on model output when growth rate was low, which is consistent with our observations. In addition, reduced conversion efficiency at high ration levels may contribute to variable model performance, thereby implying that waste losses should be modeled as a function of ration size for esocids. Our findings support earlier field tests of the esocid bioenergetic model and indicate that food consumption is generally overestimated by the model, particularly in winter months and for fish exhibiting low feeding and growth rates.

Chipps, S. R.; Einfalt, L. M.; Wahl, D. H.

2000-01-01

313

Fundamental understanding, prediction and validation of rotor vibratory loads in steady-level flight  

NASA Astrophysics Data System (ADS)

This work isolates the physics of aerodynamics and structural dynamics from the helicopter rotor aeromechanics problem, investigates them separately, identifies the prediction deficiencies in each, improves upon them, and couples them back together. The objective is to develop a comprehensive analysis capability for accurate and consistent prediction of rotor vibratory loads in steady level flight. The rotor vibratory loads are the dominant source of helicopter vibration. There are two critical vibration regimes for helicopters in steady level flight: (1) low speed transition and (2) high speed forward flight. The mechanism of rotor vibration at low speed transition is well understood---inter-twinning of blade tip vortices below the rotor disk. The mechanism of rotor vibration at high speed is not clear. The focus in this research is on high speed flight. The goal is to understand the key mechanisms involved and accurately model them. Measured lift, chord force, pitching moment and damper force from the UH-60A Flight Test Program are used to predict, validate and refine the rotor structural dynamics. The prediction errors originate entirely from structural modeling. Once validated, the resultant blade deformations are used to predict and validate aerodynamics. Air loads are calculated using a table look up based unsteady lifting-line model and compared with predictions from a 3-dimensional unsteady CFD model. Both Navier-Stokes and Euler predictions are studied. (Abstract shortened by UMI.) The 3D Navier-Stokes CFD analysis is then consistently coupled with a rotor comprehensive analysis to improve prediction of rotor vibratory loads at high speed. The CFD-comprehensive code coupling is achieved using a loose coupling methodology. The CFD analysis significantly improves section pitching moment prediction near the blade tip, because it captures the steady and unsteady 3D transonic effects. Accurate pitching moments drive elastic twist deformations which together with a refined rotor wake model generate the right vibratory airload harmonics at all radial stations. The flap bending moments, torsion bending moments and pitch link load predictions are significantly improved by CFD coupling. (Abstract shortened by UMI.)

Datta, Anubhav

314

Fuzzy logic control of steam generator water level in pressurized water reactors  

SciTech Connect

In this paper a fuzzy logic controller is applied to control the steam generator water level in a pressurized water reactor. The method does not require a detailed mathematical mode of the object to be controlled. The design is based on a set of linguistic rules that were adopted from the human operator's experience. After off-line fuzzy computation, the controller is a lookup table, and thus, real-time control is achieved. Shrink-and-swell phenomena are considered in the linguistic rules, and the simulation results show that their effect is dramatically reduced. The performance of the control system can also be improved by changing the input and output scaling factors, which is convenient for on-line tuning.

Kuan, C.C.; Lin, C.; Hsu, C.C. (National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Nuclear Engineering)

1992-10-01

315

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...  

Code of Federal Regulations, 2011 CFR

...Shipping 2 2011-10-01 2011-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks...BOILERS General Requirements § 52.01-110 Water-level indicators, water columns,...

2011-10-01

316

Predicting Fecal Coliform Bacteria Levels in the Charles River, Massachusetts, USA  

Microsoft Academic Search

In Massachusetts, the Charles River Watershed Association conducts a regular water quality monitoring and public notification program in the Charles River Basin during the recreational season to inform users of the rivers health. This program has relied on laboratory analyses of river samples for fecal coliform bacteria levels, however, results are not available until at least 24 hours after sampling.

Anna Eleria; Richard M. Vogel

2005-01-01

317

RADIOLYTIC HYDROGEN GENERATION INSAVANNAH RIVER SITE (SRS) HIGH LEVEL WASTETANKS COMPARISON OF SRS AND HANFORDMODELING PREDICTIONS  

Microsoft Academic Search

In the high level waste tanks at the Savannah River Site (SRS), hydrogen is produced continuously by interaction of the radiation in the tank with water in the waste. Consequently, the vapor spaces of the tanks are purged to prevent the accumulation of H and possible formation of a flammable mixture in a tank. Personnel at SRS have developed an

C Crawford; N Ned Bibler

2009-01-01

318

Resting-state glutamate level in the anterior cingulate predicts blood-oxygen level-dependent response to cognitive control.  

PubMed

The dorsal anterior cingulate cortex (dACC) is a core structure for the governing of cognitive control, and recent studies have shown that interindividual differences in dACC anatomy are associated with corresponding differences in the ability for cognitive control. However, individuals differ not only in anatomical features of dACC, but also exhibit substantial variability regarding the biochemical characteristics of the dACC. In this study, we combined magnetic resonance spectroscopy ((1)H-MRS) and functional magnetic resonance imaging (fMRI), finding that interindividual differences of glutamate levels in the dACC during resting-state predict the strength of the blood-oxygen level-dependent (BOLD) response to a task requiring cognitive control. This relationship was observed in the retrosplenial cortex, the orbitofrontal cortex, the inferior parietal lobe, and the basal ganglia. More specifically, individuals with low resting-state glutamate levels in the dACC showed an increased BOLD response when the task demands were high, whereas high-glutamate individuals showed the opposite pattern of an increased BOLD response when the task demands were low. Thus, we show here that individual variability of glutamate levels is directly related to how the brain implements cognitive control. PMID:22411802

Falkenberg, Liv E; Westerhausen, René; Specht, Karsten; Hugdahl, Kenneth

2012-03-12

319

Sensitivity analyses in pit lake prediction, Martha Mine, New Zealand 1: Relationship between turnover and input water density  

Microsoft Academic Search

Turnover events in pit lakes influence the water quality of pit lakes by homogenizing the chemistry of mixing layers and distributing dissolved oxygen, hence limnologic models that predict the depth of annual turnover are required for predictive studies of post-mining pit lake water quality. This study demonstrates a limnologic prediction of a proposed pit lake at the Martha Au–Ag Mine,

Devin N. Castendyk; Jenny G. Webster-Brown

2007-01-01

320

Increases of plasma eosinophil major basic protein levels late in pregnancy predict onset of labor.  

PubMed Central

Major basic protein (MBP), the core of the eosinophil granule, is a potent toxin for parasites and mammalian cells; it also causes histamine release from mast cells and basophils. Plasma levels of MBP are increased in all pregnant women, and MBP has been localized by immunofluorescence to placental X cells and placental-site giant cells. Analyses of plasma MBP levels during pregnancy showed a striking correlation between increases late in the third trimester and spontaneous onset of labor. In one case with premature labor, the plasma MBP level also was increased coincidentally with labor. In contrast, in cases of prolonged gestation in which labor was induced, there were no late increases in MBP levels. Also, uterine contraction during spontaneous labor or oxytocin-induced labor did not cause elevations of plasma MBP. Measurement of plasma MBP levels in pregnancy may be useful for the prediction of labor and for the development of new means of intervention for premature labor and prolonged gestation.

Wasmoen, T L; Coulam, C B; Leiferman, K M; Gleich, G J

1987-01-01

321

Predicting hemoglobin levels in whole blood donors using transition models and mixed effects models  

PubMed Central

Background To optimize the planning of blood donations but also to continue motivating the volunteers it is important to streamline the practical organization of the timing of donations. While donors are asked to return for donation after a suitable period, still a relevant proportion of blood donors is deferred from donation each year due to a too low hemoglobin level. Rejection of donation may demotivate the candidate donor and implies an inefficient planning of the donation process. Hence, it is important to predict the future hemoglobin level to improve the planning of donors’ visits to the blood bank. Methods The development of the hemoglobin prediction rule is based on longitudinal (panel) data from blood donations collected by Sanquin (the only blood product collecting and supplying organization in the Netherlands). We explored and contrasted two popular statistical models, i.e. the transition (autoregressive) model and the mixed effects model as plausible models to account for the dependence among subsequent hemoglobin levels within a donor. Results The predictors of the future hemoglobin level are age, season, hemoglobin levels at the previous visits, and a binary variable indicating whether a donation was made at the previous visit. Based on cross-validation, the areas under the receiver operating characteristic curve (AUCs) for male donors are 0.83 and 0.81 for the transition model and the mixed effects model, respectively; for female donors we obtained AUC values of 0.73 and 0.72 for the transition model and the mixed effects model, respectively. Conclusion We showed that the transition models and the mixed effects models provide a much better prediction compared to a multiple linear regression model. In general, the transition model provides a somewhat better prediction than the mixed effects model, especially at high visit numbers. In addition, the transition model offers a better trade-off between sensitivity and specificity when varying the cut-off values for eligibility in predicted values. Hence transition models make the prediction of hemoglobin level more precise and may lead to less deferral from donation in the future.

2013-01-01

322

Individual changes in clozapine levels after smoking cessation: results and a predictive model.  

PubMed

Published reports document 20-40% lower mean serum clozapine concentrations in smokers compared with nonsmokers due to enzyme induction. Despite the increase in nonsmoking psychiatric facilities in the United States, previous studies have not tracked individual changes in serum clozapine levels after smoking cessation. Clozapine level changes were analyzed in 11 patients at Oregon State Hospital who were on stable clozapine doses, before and after implementation of a hospital-wide nonsmoking policy. A mean increase in clozapine levels of 71.9% (442.4 ng/ml +/- 598.8 ng/ml) occurred upon smoking cessation (p < .034) from a baseline level of 550.2 ng/ml (+/- 160.18 ng/ml). One serious adverse event, aspiration pneumonia, was associated with a nonsmoking serum clozapine level of 3066 ng/ml. Elimination of statistically extreme results generated a mean increase of 57.4 % or 284.1 ng/ml (+/- 105.2 ng/ml) for the remaining cases (p < .001) and permitted construction of a linear model which explains 80.9% of changes in clozapine levels upon smoking cessation (F = 34.9;p = .001): clozapine level as nonsmoker = 45.3 + 1.474 (clozapine level as smoker). These findings suggest that significant increases in clozapine levels upon smoking cessation may be predicted by use of a model. Those with high baseline levels should be monitored for serious adverse events. PMID:11763003

Meyer, J M

2001-12-01

323

Statistical prediction intervals for the evaluation of ground-water quality  

Microsoft Academic Search

Factors for a normal distribution are given such that one may be 99% confident that the two-sided prediction interval chi-bar +- rs or the one-sided prediction several chi-bar + rs will contain all of the kappa future values, where chi-bar and s are the sample means and standard deviation obtained from n previous values. In the context of ground-water monitoring,

Robert D. Gibbons

1987-01-01

324

Predictive model for disinfection by-product in Alexandria drinking water, northern west of Egypt.  

PubMed

Chlorine has been utilized in the early stages of water treatment processes as disinfectant. Disinfection for drinking water reduces the risk of pathogenic infection but may pose a chemical threat to human health due to disinfection residues and their by-products (DBP) when the organic and inorganic precursors are present in water. In the last two decades, many modeling attempts have been made to predict the occurrence of DBP in drinking water. Models have been developed based on data generated in laboratory-scale and field-scale investigations. The objective of this paper is to develop a predictive model for DBP formation in the Alexandria governorate located at the northern west of Egypt based on field-scale investigations as well as laboratory-controlled experimentations. The present study showed that the correlation coefficient between trihalomethanes (THM) predicted and THM measured was R (2)?=?0.88 and the minimum deviation percentage between THM predicted and THM measured was 0.8 %, the maximum deviation percentage was 89.3 %, and the average deviation was 17.8 %, while the correlation coefficient between dichloroacetic acid (DCAA) predicted and DCAA measured was R (2)?=?0.98 and the minimum deviation percentage between DCAA predicted and DCAA measured was 1.3 %, the maximum deviation percentage was 47.2 %, and the average deviation was 16.6 %. In addition, the correlation coefficient between trichloroacetic acid (TCAA) predicted and TCAA measured was R (2)?=?0.98 and the minimum deviation percentage between TCAA predicted and TCAA measured was 4.9 %, the maximum deviation percentage was 43.0 %, and the average deviation was 16.0 %. PMID:23852584

Abdullah, Ali M; Hussona, Salah El-Dien

2013-07-14

325

Predicting impacts of increased CO? and climate change on the water cycle and water quality in the semiarid James River Basin of the Midwestern USA.  

PubMed

Emissions of greenhouse gases and aerosols from human activities continue to alter the climate and likely will have significant impacts on the terrestrial hydrological cycle and water quality, especially in arid and semiarid regions. We applied an improved Soil and Water Assessment Tool (SWAT) to evaluate impacts of increased atmospheric CO(2) concentration and potential climate change on the water cycle and nitrogen loads in the semiarid James River Basin (JRB) in the Midwestern United States. We assessed responses of water yield, soil water content, groundwater recharge, and nitrate nitrogen (NO(3)-N) load under hypothetical climate-sensitivity scenarios in terms of CO(2), precipitation, and air temperature. We extended our predictions of the dynamics of these hydrological variables into the mid-21st century with downscaled climate projections integrated across output from six General Circulation Models. Our simulation results compared against the baseline period 1980 to 2009 suggest the JRB hydrological system is highly responsive to rising levels of CO(2) concentration and potential climate change. Under our scenarios, substantial decrease in precipitation and increase in air temperature by the mid-21st century could result in significant reduction in water yield, soil water content, and groundwater recharge. Our model also estimated decreased NO(3)-N load to streams, which could be beneficial, but a concomitant increase in NO(3)-N concentration due to a decrease in streamflow likely would degrade stream water and threaten aquatic ecosystems. These results highlight possible risks of drought, water supply shortage, and water quality degradation in this basin. PMID:22641243

Wu, Yiping; Liu, Shuguang; Gallant, Alisa L

2012-05-26

326

Nitrates in drinking water and methemoglobin levels in pregnancy: a longitudinal study  

Microsoft Academic Search

BACKGROUND: Private water systems are more likely to have nitrate levels above the maximum contaminant level (MCL). Pregnant women are considered vulnerable to the effects of exposure to high levels of nitrates in drinking water due to their altered physiological states. The level of methemoglobin in the blood is the biomarker often used in research for assessing exposure to nitrates.

Deana M Manassaram; Lorraine C Backer; Rita Messing; Lora E Fleming; Barbara Luke; Carolyn P Monteilh

2010-01-01

327

Changes in water level, land use, and hydrological budget in a semi-permanent playa lake, southwest Spain.  

PubMed

Medina playa lake, a Ramsar site in western Andalusia, is a brackish lowland lake of 120 ha with an average depth of 1 m. Water flows into Medina from its 1,748-ha watershed, but the hydrology of the lake has not previously been studied. This paper describes the application of a water budget model on a monthly scale over a 6-year period, based on a conceptual hydrological model, and considers different future scenarios after calibration to improve the understanding of the lake's hydrological functioning. Climatic variables from a nearby weather station and observational data (water-level evolution) were used to develop the model. Comparison of measured and predicted values demonstrated that each model component provided a reasonable output with a realistic interaction among the components. The model was then used to explore the potential consequences of land-use changes. Irrigation of olive groves would significantly reduce both the hydroperiod (becoming dry 15% of the time) and the average depth of the lake (water level <0.5 m 40% of the time). On the other hand, removal of an artificial overflow would double the average flooded surface area during high-water periods. The simulated water balance demonstrates that the catchment outputs are dominated by lake evaporation and surface outflow from the lake system to a creek. Discrepancies between predicted and observed water levels identify key areas of uncertainty for future empirical research. The study provides an improved basis for future hydrological management of the catchment and demonstrates the wider utility of this methodology in simulating this kind of system. This methodology provides a realistic appraisal of potential land-use management practices on a catchment-wide scale and allows predictions of the consequences of climate change. PMID:21461983

Rodríguez-Rodríguez, M; Green, A J; López, R; Martos-Rosillo, S

2011-04-04

328

Multimodel Prediction of Water Flow in a Field Soil Using Pedotransfer Functions  

NASA Astrophysics Data System (ADS)

Combining predictions using various independent models, often called multimodel prediction, has become a very popular technique in climate prediction and is now increasingly being used also in subsurface hydrology. The objectives of this work were (a) to compare different methods of multimodel prediction of the field soil water regime using pedotransfer functions, and (b) to see whether the calibration of a flow model with field data can be replaced by multimodel predictions. The multimodel prediction in this work consisted of running the Richards model with outputs of individual PTFs and then combining the obtained outputs into a single prediction. We compared weighing predictions from individual models by (1) using only the best model, (2) assigning equal weights, (3) using the unconstrained superensemble (i. e. regressing measured values to outputs of individual models), (4) using singular value decomposition in the regression, (5) using Bayesian model averaging, and (6) applying weights derived from the Kullback-Leibler information for each model. We evaluated the weighing methods in terms of their accuracy (i. e. errors in reproducing the training, or hindcast, datasets), and reliability (i.e., errors in reproducing the test datasets). The two best weighing methods (Bayesian model averaging and regression with singular value decomposition) had average accuracy and reliability RMSE values of about 0.01 cm3cm-3 at 35 cm depth, and of about 0.005 cm3cm-3 at larger depths for one month monitoring and 13 months of testing. Calibrating the Richards model resulted in RMSE values of 0.009 cm3cm-3 at 35 cm depth and from 0.004 to 0.006 cm3cm-3 at larger depths. This indicates that monitoring of the soil water regime in combination with multimodel prediction instead of calibrating the flow model can be a viable approach to simulating field water flow in the vadose zone.

Guber, A. K.; Pachepsky, Y. A.; Jacques, D.; van Genuchten, M. T.; Nemesh, A.; Simunek, J.; Nicholson, T. J.; Cady, R. E.

2007-05-01

329

Quantitative structure-ion intensity relationship strategy to the prediction of absolute levels without authentic standards.  

PubMed

The lack of authentic standards represents a major bottleneck in the quantitative analysis of complex samples. Here we propose a quantitative structure and ionization intensity relationship (QSIIR) approach to predict the absolute levels of compounds in complex matrixes. An absolute quantitative method for simultaneous quantification of 25 organic acids was firstly developed and validated. Napierian logarithm (LN) of the relative slope rate derived from the calibration curves was applied as an indicator of the relative ionization intensity factor (RIIF) and serves as the dependent variable for building a QSIIR model via a multiple linear regression (MLR) approach. Five independent variables representing for hydrogen bond acidity, HOMO energy, the number of hydrogen bond donating group, the ratio of organic phase, and the polar solvent accessible surface area were found as the dominant contributors to the RIIF of organic acids. This QSIIR model was validated to be accurate and robust, with the correlation coefficients (R(2)), R(2) adjusted, and R(2) prediction at 0.945, 0.925, and 0.89, respectively. The deviation of accuracy between the predicted and experimental value in analyzing a real complex sample was less than 20% in most cases (15/18). Furthermore, the high adaptability of this model was validated one year later in another LC/MS system. The QSIIR approach is expected to provide better understanding of quantitative structure and ionization efficiency relationship of analogous compounds, and also to be useful in predicting the absolute levels of analogous analytes in complex mixtures. PMID:23972977

Wu, Liang; Wu, Yuzheng; Shen, Hanyuan; Gong, Ping; Cao, Lijuan; Wang, Guangji; Hao, Haiping

2013-07-17

330

Effects of water level fluctuation on radial oxygen loss, root porosity, and nitrogen removal in subsurface vertical flow wetland mesocosms  

Microsoft Academic Search

Laboratory experiments were conducted to investigate the effects of water level fluctuation on plant radial oxygen loss (ROL), root porosity, plant growth performance, and nitrogen dynamics in vertical subsurface flow wetland mesocosms. Four types of mesocosms were used: control with static water level, control with fluctuating water level, static water level with plants, and fluctuating water level with plants. Typha

S. Sasikala; Norio Tanaka; H. S. Y. Wah Wah; K. B. S. N. Jinadasa

2009-01-01

331

A Cellular Level Approach to Predicting Resting Energy Expenditure: Evaluation of Applicability in Adolescents  

PubMed Central

We previously derived a cellular level approach for a whole-body resting energy expenditure (REE) prediction model by using organ and tissue mass measured by magnetic resonance imaging (MRI) combined with their individual cellularity and assumed stable-specific resting metabolic rates. Although this approach predicts REE well in both young and elderly adults, there were no studies in adolescents that specifically evaluated REE in relation to organ–tissue mass. It is unclear whether the approach can be applied to rapidly growing adolescents. The aim of the present study was to evaluate the applicability of the previous developed REE prediction model in adolescents, and to compare its applicability in young and elderly adults. Specifically, we tested the hypothesis that measured REE can be predicted from a combination of individual organ and tissue mass and their related cellularity. This was a 2-year longitudinal investigation. Twenty healthy male subjects with a mean age of 14.7 years had REE, organ and tissue mass, body cell mass, and fat-free mass (FFM) measured by indirect calorimetry, whole-body MRI, whole-body 40K counting and dual-energy X-ray absorptiometry, respectively. The predicted REE (REEp; mean ± SD, 1,487 ± 238 kcal/day) was correlated with the measured REE (REEm, 1,606 ± 237 kcal/day, r = 0.76, P < 0.001). The mean difference (118 ± 165 kcal/day) between REEm and REEp was significant (P = 0.0047), accounting for 7.3% of REEm for the entire group. The present study, the first of its type in adolescents, does not support the applicability of the organ–tissue-based REE prediction model during rapid adolescent growth. A modified general REE prediction model is thus suggested which may account for the higher REE/FFM ratio observed in adolescents.

WANG, ZIMIAN; HEYMSFIELD, STEVEN B.; YING, ZHILIANG; PIERSON, RICHARD N.; GALLAGHER, DYMPNA; GIDWANI, SONIA

2010-01-01

332

Prediction of sea water intrusion for mining activity in close precincts of sea shore.  

PubMed

The mining lease area of Surka [District Bhavnagar, Gujarat (India)] is located within 6-12 km horizontal distance of sea shore of Gulf of Cambay. Whenever, there will be onset of lignite extraction, there will be always a threat of sea water intrusion into the mining lease area due to its close proximity to seashore. This article describes the prediction of sea water intrusion into the lease area of whole mining block using Ghyben-Herzberg relation between fresh and saline water, Remote Sensing, Ground Truth verification, Electrical Resistivity Survey and groundwater table monitored during the year 2004. As per the Ghyben-Herzberg relation, results show that there will not be sea water intrusion. If there is excess pumping of water then also the basement rock below the lignite seam will put hindrance to any possible upconing of saline water interface. PMID:24083098

Singh, Awanindra Pratap; Gupta, Prem Kumar; Khandelwal, Manoj

2013-08-29

333

Development of methane-water potential from first-principles for predicting methane hydrate phase equilibria  

Microsoft Academic Search

Accurate intermolecular potentials between hydrocarbons and water are essential for the prediction of properties of systems containing these components. Unfortunately, current experimental techniques are unable to measure directly the interaction potential between methane and water molecules. Therefore we have used quantum mechanical calculations, both ab initio (MP2\\/CCSD) and density functional theory (DFT) calculations, in order to determine the H2O-CH4 potential

Zhitao Cao; Jefferson Tester; Bernhardt Trout

2001-01-01

334

Predicting the permeability function for unsaturated soils using the soil-water characteristic curve  

Microsoft Academic Search

The coefficient of permeability for an unsaturated soil is primarily determined by the pore-size distribution of the soil and can be predicted from the soil-water characteristic curve. A general equation, which describes the soil-water characteristic curve over the entire suction range (i.e., from 0 to 10 6 kPa), was proposed by the first two authors in another paper. This equation

D. G. Fredlund; ANQUING XING; Shangyan Huang

1994-01-01

335

Prediction of micro-bubble dissolution characteristics in water and seawater  

Microsoft Academic Search

This paper is concerned with the prediction of micro-bubble dissolution characteristics in water and seawater when microbubbles are generated by a Sadatomi-type micro-bubble generator (2003) with a spherical body in a flowing liquid tube. In the experiments, in order to know the effects of the salinity on the characteristics, tap water and an artificial seawater with different salt concentrations of

Akimaro Kawahara; Michio Sadatomi; Hidetoshi Matsuura; Mayo Tominaga; Masanori Noguchi; Fuminori Matsuyama

2009-01-01

336

Deterministic and Stochastic Predictions of Motion Dynamics of Cylindrical Mines Falling Through Water  

Microsoft Academic Search

A physics-based computational model has been developed that is capable of reliably predicting the motion of a 3-D mine-shaped object impacting the water surface from the air, and subsequently, dropping through the water toward the sea bottom. This deterministic model [mine's six-degree-of-freedom dynamics (MINE6D)] accounts for six-degree-of-freedom motions of the body including unsteady hydrodynamic interaction effects. MINE6D allows for physics-based

Jennifer Mann; Yuming Liu; Yonghwan Kim; Dick K. P. Yue

2007-01-01

337

Physicochemical interpretation and prediction of the dimyristoyl phosphatidyl choline–water partition coefficient  

Microsoft Academic Search

The dimyristoyl phosphatidyl choline (DMPC)–water partition coefficient (logKDMPC–W) has been proposed as an alternative to the 1-octanol–water system (logKOW) for describing molecular hydrophobicity. In this study literature values of logKDMPC–W for 49 compounds were collated. Quantitative structure–activity relationships (QSARs) were developed for logKDMPC–W in an attempt to develop a predictive model for its estimation and to investigate its meaning. Despite

Hiren Patel; T. Wayne Schultz; Mark T. D Cronin

2002-01-01

338

Predicting Microstructural-Level Residual Stresses and Crack Paths in Ceramics  

SciTech Connect

Microstructural-level residual stresses arise in ceramics due to thermal expansion anisotropy. The magnitude of these stresses can be very high and may cause spontaneous microcracking during the processing of these materials. The orientation data obtained by backscattered electron diffraction and grain boundary energies obtained by AFM were used in conjunction with an object oriented finite element analysis package (OOF) to predict the magnitude of residual stresses in alumina. Crack initiation and propagation were also simulated based on the Griffith fracture criterion.

Cater, W.C.; Glass, S.J.; Rohrer, G.S.; Saylor, D.M.; Vedula, V.R.

1999-05-19

339

Intercurrent clinical events are predictive of plasma C-reactive protein levels in hemodialysis patients  

Microsoft Academic Search

Intercurrent clinical events are predictive of plasma C-reactive protein levels in hemodialysis patients.BackgroundIn chronic hemodialysis (HD) patients, the repetitive induction of the acute phase response (APR) may induce a chronic micro-inflammatory state, leading to various long-term complications.MethodsThe present prospective study was designed to assess the alterations in the APR in 74 patients who were randomized to HD with a high-flux

Anne Van Tellingen; Muriel P C Grooteman; Margreet Schoorl; Piet C M Bartels; Marianne Schoorl; Tjeerd Van Der Ploeg; Piet M Ter Wee; Menso J Nubé

2002-01-01

340

Predicting visual fixations on video based on low-level visual features  

Microsoft Academic Search

T}o what extent can a computational model of the bottom–up visual attention predict what an observer is looking at? {W}hat is the contribution of the low-level visual features in the attention deployment? {T}o answer these questions, a new spatio-temporal computational model is proposed. {T}his model incorporates several visual features; therefore, a fusion algorithm is required to combine the different saliency

Olivier Le Meur; Patrick Le Callet; Dominique Barba

2007-01-01

341

Increased Plasma Methylmalonic Acid Level Does Not Predict Clinical Manifestations of Vitamin B12 Deficiency  

Microsoft Academic Search

Background: The prevalence of vitamin B12 defi- ciency, defined as an elevated concentration of plasma methylmalonic acid (P-MMA), has been estimated to be 15% to 44% in the elderly. However, we do not know whether an increased P-MMA level actually indicates or predicts a clinical condition in need of treatment. Participants and Methods: In a follow-up study, 432 individuals not

Anne-Mette Hvas; Jørgen Ellegaard; Ebba Nexø

2001-01-01

342

C-reactive protein levels and clinically important predictive outcomes in stable COPD patients  

Microsoft Academic Search

The aim of this study was to determine the relationship between C-reactive protein (CRP) levels and factors known to predict outcome in stable chronic obstructive pulmonary disease (COPD) patients. The following were studied in 130 stable COPD patients: spirometry, lung volume, arterial oxygen tension (Pa,O2), dyspnoea, 6-min walk distance (6MWD), body mass index, fat-free mass index, BODE (body mass index,

J. P. de Torres; E. Cordoba-Lanus; C. Lopez-Aguilar; M. Muros de Fuentes; A. Montejo de Garcini; A. Aguirre-Jaime; B. R. Celli; C. Casanova; Ctra del Rosario; Santa Cruz de Tenerife; Canary Islands

2006-01-01

343

Self-Enhancement and Self-Stability Predict School Achievement at the National Level  

Microsoft Academic Search

This article uses as a starting point S. Heine's hypothesis that higher self-enhancement correlates with self-stability and the combination of the two may predict lower interest in some types of self-improvement. This hypothesis is tested at the ecological level. World Values Survey items are used to demonstrate that there exists a bipolar cultural dimension with two main strongly correlated facets.

Michael Minkov

2008-01-01

344

Plasma cytokine levels predict mortality in patients with acute renal failure  

Microsoft Academic Search

Plasma cytokine levels predict mortality in patients with acute renal failure.BackgroundCritically ill patients with acute renal failure (ARF) experience a high mortality rate. Animal and human studies suggest that proinflammatory cytokines lead to the development of a systemic inflammatory response syndrome (SIRS), which is temporally followed by a counter anti-inflammatory response syndrome (CARS). This process has not been specifically described

Edith M. Simmons; JONATHAN HIMMELFARB; M. Tugrul Sezer; Glenn M. Chertow; Ravindra L. Mehta; Emil P. Paganini; SHARON SOROKO; STEPHANIE FREEDMAN; KAREN BECKER; DANIEL SPRATT; YU SHYR; T. Alp Ikizler

2004-01-01

345

Higher Adiponectin Levels Predict Greater Weight Gain in Healthy Women in the Nurses' Health Study  

Microsoft Academic Search

Adiponectin and resistin's possible roles in weight regulation have received little attention. We tested the hypothesis that adipokine levels predict future weight gain in women in the Nurses' Health Study. Among women who provided blood samples in 1990, we studied 1,063 women who did not develop diabetes (“healthy”) and 984 women who subsequently developed diabetes. Total and high-molecular-weight (HMW) adiponectin

Marie-France Hivert; Qi Sun; Peter Shrader; Christol S. Mantzoros; James B. Meigs; Frank B. Hu

2011-01-01

346

Role of patient education level in predicting macrosomia among women with gestational diabetes mellitus  

Microsoft Academic Search

Objective:To evaluate the role of education level in predicting the risk of macrosomia among women with gestational diabetes mellitus.Study design:Women with gestational diabetes, who were referred to the California Diabetes and Pregnancy Sweet Success Program between June 2001 and December 2002, were included in the study. Multiple logistic regression was used estimate the risk of macrosomia, defined as a birth

J H Chung; K J Voss; A B Caughey; D A Wing; E J D Henderson; C A Major

2006-01-01

347

Low Pro-Brain Natriuretic Peptide Levels Predict Benign Clinical Outcome in Acute Pulmonary Embolism  

Microsoft Academic Search

Background—The role of pro-brain natriuretic peptide (proBNP) for the prediction of clinical outcome has not been examined in patients with acute pulmonary embolism (PE). Methods and Results—ProBNP levels were measured in 73 patients with acute PE within 4 hours of admission. Adverse clinical outcome was defined as in-hospital death or the need for at least 1 of the following: cardiopulmonary

Nils Kucher; Gert Printzen; Tanja Doernhoefer; Stephan Windecker; Bernhard Meier; Otto Martin Hess

2011-01-01

348

Effect of time step size and turbulence model on the open water hydrodynamic performance prediction of contra-rotating propellers  

NASA Astrophysics Data System (ADS)

A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibration. Compared with the single-screw system, it is more difficult for the open water performance prediction because forward and aft propellers interact with each other and generate a more complicated flow field around the CRPs system. The current work focuses on the open water performance prediction of contra-rotating propellers by RANS and sliding mesh method considering the effect of computational time step size and turbulence model. The validation study has been performed on two sets of contra-rotating propellers developed by David W Taylor Naval Ship R & D center. Compared with the experimental data, it shows that RANS with sliding mesh method and SST k-? turbulence model has a good precision in the open water performance prediction of contra-rotating propellers, and small time step size can improve the level of accuracy for CRPs with the same blade number of forward and aft propellers, while a relatively large time step size is a better choice for CRPs with different blade numbers.

Wang, Zhan-zhi; Xiong, Ying

2013-04-01

349

Rapidly Measured Indicators of Recreational Water Quality Are Predictive of Swimming-Associated Gastrointestinal Illness  

PubMed Central

Standard methods to measure recreational water quality require at least 24 hr to obtain results, making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in ? 2 hr have been developed. Application of rapid methods could give considerably more accurate and timely assessments of recreational water quality. We conducted a prospective study of beachgoers at two Great Lakes beaches to examine the association between recreational water quality, obtained using rapid methods, and gastrointestinal (GI) illness after swimming. Beachgoers were asked about swimming and other beach activities and 10–12 days later were asked about the occurrence of GI symptoms. We tested water samples for Enterococcus and Bacteroides species using the quantitative polymerase chain reaction (PCR) method. We observed significant trends between increased GI illness and Enterococcus at the Lake Michigan beach and a positive trend for Enterococcus at the Lake Erie beach. The association remained significant for Enterococcus when the two beaches were combined. We observed a positive trend for Bacteroides at the Lake Erie beach, but no trend was observed at the Lake Michigan beach. Enterococcus samples collected at 0800 hr were predictive of GI illness that day. The association between Enterococcus and illness strengthened as time spent swimming in the water increased. This is the first study to show that water quality measured by rapid methods can predict swimming-associated health effects.

Wade, Timothy J.; Calderon, Rebecca L.; Sams, Elizabeth; Beach, Michael; Brenner, Kristen P.; Williams, Ann H.; Dufour, Alfred P.

2006-01-01

350

Rapidly measured indicators of recreational water quality are predictive of swimming-associated gastrointestinal illness.  

PubMed

Standard methods to measure recreational water quality require at least 24 hr to obtain results, making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in water quality. We conducted a prospective study of beachgoers at two Great Lakes beaches to examine the association between recreational water quality, obtained using rapid methods, and gastrointestinal (GI) illness after swimming. Beachgoers were asked about swimming and other beach activities and 10-12 days later were asked about the occurrence of GI symptoms. We tested water samples for Enterococcus and Bacteroides species using the quantitative polymerase chain reaction (PCR) method. We observed significant trends between increased GI illness and Enterococcus at the Lake Michigan beach and a positive trend for Enterococcus at the Lake Erie beach. The association remained significant for Enterococcus when the two beaches were combined. We observed a positive trend for Bacteroides at the Lake Erie beach, but no trend was observed at the Lake Michigan beach. Enterococcus samples collected at 0800 hr were predictive of GI illness that day. The association between Enterococcus and illness strengthened as time spent swimming in the water increased. This is the first study to show that water quality measured by rapid methods can predict swimming-associated health effects. PMID:16393653

Wade, Timothy J; Calderon, Rebecca L; Sams, Elizabeth; Beach, Michael; Brenner, Kristen P; Williams, Ann H; Dufour, Alfred P

2006-01-01

351

Predicting interfacial tension between water and nonpolar fluids from a Cahn-type theory.  

PubMed

We propose an accurate method to predict interfacial tension between water and nonpolar fluids by using Cahn gradient theory. The only necessary elements are (i) a water contact energy function and (ii) an equation of state (EoS) for the nonpolar fluid, chosen here as the Peng-Robinson EoS. The contact energy, a function of the fluid (adsorbate) surface density, is related to interfacial tension (IFT) by means of the Gibbs adsorption equation. Examining a large number of IFT data, we observe that the water contact energy is a universal function of adsorbate's surface density when proper scaling variables are used: it depends neither on adsorbate nor on temperature. A corresponding-states principle appears to govern the interfacial behavior between water and any nonpolar compound that is sparingly soluble in water. A predictive method (without any adjustable parameter) is therefore available for estimating IFT between water and any nonpolar fluid, whether the fluid is in supercritical or in subcritical states. The method performs well when the adsorbate is sparingly soluble in water, but slightly overestimates IFTs when the adsorbate's solubility in water is significant (e.g., CO2 and H2S). A similar behavior should also hold for interfaces involving a solid substrate. PMID:17973408

Shah, Virenkumar; Broseta, Daniel

2007-10-31

352

Validation-comparison of predicted and measured levels in industrial spaces  

NASA Astrophysics Data System (ADS)

Financed by the German Federal Agency for Labor and Social Affairs, several methods of calculating the noise propagation in industrial halls were used for about 150 halls and compared with measurements. With all noise sources, such as machines and equipment stopped, a dodecahedron loudspeaker emitting broadband noise was used, and the octave-band levels were measured on different propagation paths. The room geometry and equipment in the room were entered into uniform datasets, the calculation methods were applied to each dataset, and the results in terms of deviations between calculated and measured values were evaluated statistically. The prediction method with the smallest deviations was chosen for further evaluation. This method, which uses mirror images with approximations and takes into account diffraction with a method first developed by Kuttruff and extended by Jovicic, uses mean values for fittings and absorption at walls and ceilings. This method has been incorporated into VDI 3760, and will be extended in the future to take into account screening by single objects and the real distribution of absorptive materials on surfaces. Representative experimental results, calculation techniques, predicted levels, and deviations between measured and predicted levels are presented.

Probst, Wolfgang

2002-11-01

353

Prospects for useful sea-level predictions from Earth-system models (Invited)  

NASA Astrophysics Data System (ADS)

Earth-system models (ESMs) to date have been unable to provide useful predictions of 21st century sea-level rise, largely because of uncertainties in the dynamic response of the Greenland and Antarctic ice sheets. As a result, planners and policymakers have had to rely on semi-empirical methods and extrapolations of current trends. In order to obtain comprehensive, physically-based sea-level predictions from ESMs, two major innovations are required: (1) Ice sheet models must represent the physical processes responsible for fast ice flow, and (2) these models must be integrated with models of the ocean, land, and atmosphere. There has been much recent progress in developing ice sheet models that include (among other improvements) higher-order stresses, adaptive and unstructured grids, and more realistic treatments of basal sliding and iceberg calving. Progress has been slower, however, in coupling ice sheet models to ESMs. In particular, work is needed to simulate small-scale ice-ocean interactions that could trigger the abrupt retreat of marine ice sheets. The barriers to coupling are cultural and technical as well as scientific. As new ice sheet models are added to ESMs, scientific understanding will grow quickly, but large uncertainties in sea-level predictions will likely remain. New assessment mechanisms are needed to communicate complex results to end users in a useful, timely fashion.

Lipscomb, W. H.

2010-12-01

354

Strength and Comprehensiveness of District School Wellness Policies Predict Policy Implementation at the School Level  

PubMed Central

Background In 2006, all local education agencies in the United States participating in federal school meal programs were required to establish school wellness policies. The aim of this study was to document the strength and comprehensiveness of one state's written district policies using a quantitative coding tool, and test whether the strength and comprehensiveness of the written policy predicted school level implementation and practices. Methods School wellness policies from 151 Connecticut districts were evaluated using a quantitative coding system. In each district, school principal surveys were collected before and after the writing and expected implementation of wellness policies. Socio-demographic variables were assessed for each district, including enrollment, population density, political climate, racial composition and socio-economic status. Changes in school-level policy implementation before and after the federal wellness policy requirement were compared across districts by wellness policy strength, and policies were compared based on district-level demographic factors. Results Statewide, fuller implementation of nutrition and physical activity policies at the school level was reported after adoption of written policies in 2006. Districts with stronger, more comprehensive policies were more successful in implementing those policies at the school level. Some socio-demographic characteristics predicted the strength of wellness policies; larger, urban districts and districts with a greater ratio of registered Democrats to Republicans wrote stronger policies. Conclusions Written school wellness policies have the potential to promote significant improvements in the school environment. Future regulation of school wellness policies should focus on the importance of writing strong and comprehensive policies.

Henderson, Kathryn E; Falbe, Jennifer; Novak, Sarah A.; Wharton, Christopher; Long, Michael; O'Connell, Meghan L.; Fiore, Susan S.

2013-01-01

355

Water Level Station Specifications and Deliverables for Shoreline Mapping Projects.  

National Technical Information Service (NTIS)

The work performed according to the requirements and specifications of this document is required for shoreline mapping and aerial photogrammetry products and services. The first objective is to provide the tidal predictions and tidal zoning so that flight...

2009-01-01

356

Records of water levels in monitoring wells in the Gallatin Valley, southwestern Montana, 1947-93  

USGS Publications Warehouse

Water-level data were collected in the Gallatin Valley to provide a basis for evaluation of the configuration of the ground-water surface and water-level change. Water-level records collected during a 2-year study of the area and historical water-level data for 121 wells in the Gallatin Valley are summarized in the report. Well-depth and primary-aquifer data are included. The locations of the wells are shown on a map at a scale of 1:275,500.

Slagle, Steven E.

1994-01-01

357

Estimation of ecological water requirements based on habitat response to water level in Huanghe River Delta, China  

Microsoft Academic Search

In recent years, wetland ecological water requirements (EWRs) have been estimated by using hydrological and functional approaches,\\u000a but those approaches have not yet been integrated for a whole ecosystem. This paper presents a new method for calculating\\u000a wetland EWRs, which is based on the response of habitats to water level, and determines water level threshold through the\\u000a functional integrity of

Baoshan Cui; Yanyan Hua; Chongfang Wang; Xiaolin Liao; Xuejie Tan; Wendong Tao

2010-01-01

358

Chemical Fate of Brass Dust in Waters of Varying Hardness Levels.  

National Technical Information Service (NTIS)

The chemical fate of brass dust was examined at four levels of water hardness ranging from very soft to very hard water. The brass dust was added at a concentration of 10 mg/L to two set of test water at each hardness level. In the first set, the brass wa...

W. T. Muse

1988-01-01

359

Natural circulation steam generator model for optimal steam generator water level control  

Microsoft Academic Search

Several authors have cited the control of steam generator water level as an important problem in the operation of pressurized water reactor plants. In this paper problems associated with steam generator water level control are identified, and advantages of modern estimation and control theory in dealing with these problems are discussed. A new state variable steam generator model and preliminary

Feeley

1979-01-01

360

Water uptake and tensile properties of carboxylated styrene butadiene rubber based water born paints: Models for water uptake prediction  

Microsoft Academic Search

Despite significant advances in water based surface coating technology, the presence of surfactants in emulsion polymer binders leads to loss of performance after prolonged immersion in water, relative to solvent based coatings that are free of surfactant impurities. This study begins with water uptake evaluation of a range of emulsion polymer binders. A carboxylated styrene butadiene rubber latex (c-SBR) performed

Elena Jubete; Christopher M. Liauw; Norman S. Allen

2007-01-01

361

Predicting or Water Film Thickness and Velocity for Corrosion Rate Calculation in Oil-Water Flows  

Microsoft Academic Search

Experiments studying oil-water flows were conducted in a 10-cm diameter, 40-m long, horizontal pipeline. Oil (viscosity 3 cP at 25°C) and ASTM substitute seawater were used at superficial mixture velocities ranging from 0.4 to 3.0m\\/s. in situ water cut and in situ velocity along the pipe across section have been measured at a temperature of 25°C and a carbon dioxide

Hua Shi; Hongbin Wang; Lee D; William Jepson

2002-01-01

362

Forecasting future water levels to aid in flash flood risk management  

NASA Astrophysics Data System (ADS)

Flash floods are typically triggered by local intense rainfall in small catchments with short response times. The work presented explores the use of ensemble numerical weather prediction products coupled with a simplified hydrological model to forecast such floods, with up to 2 days lead time, when water level observations can be regularly assimilated. The techniques outlined are presented with reference to a case study, the Gardon d'Anduze basin in France. A Data Based Mechanistic time series model of the rainfall run-off dynamics of the catchment is constructed. The model formulated to address two common sources of observational errors, shifting baselines in the water level observation and incorrect characterisation of the magnitude of the precipitation. It is cast in a state space form shown to be an effective forecaster when driven by observed precipitation data. Substitution of ensemble precipitation forecasts the observed data is used to generate forecasts with with longer lead times. A simple adaptation of the hydrological model is used to represent the uncertainty in the forecasts that may result from incorrect characterisation of the magnitude of the forecast precipitation. Observed water levels are assimilated condition the model forecasts. They can be used both to condition the initial states to the hydrological model prior to being run with the ensemble NWP input but also to condition the hydrological forecasts generated by running the ensemble NWP inputs after they have been generated. The balance between using the hydrological forecasts of most recent NWP ensemble, or those of an older generated by an older ensemble which have undergone more data assimilation is considered.

Smith, P. J.; Beven, K.; Marchandise, A.; Pappenberger, F.

2012-04-01

363

Toward a predictive model for water and carbon fluxes of non-native trees in urban habitats  

NASA Astrophysics Data System (ADS)

There is considerable interest in estimating uptake of water and carbon by urban trees, in order to assess some of the major costs and benefits associated with maintaining or expanding urban tree cover. However, making large-scale estimates of water and carbon fluxes is challenging in urban ecosystems, where community composition and environmental conditions are highly altered and experimental data is sparse. This is particularly true in regions such as southern California, where few trees are native, yet many species can flourish given supplemental irrigation. In such scenarios one practical way to scale water and carbon fluxes may be to identify reliable traits which can be used to predict gas exchange when trees are transplanted to a new environment. To test this approach, leaf level gas exchange measurements were conducted on eight common urban tree species within the Los Angeles basin. The objective was to determine how well gas exchange parameters, including maximum photosynthesis and stomatal conductance, sensitivity of stomatal conductance to vapor pressure deficit (VPD), and water use efficiency (WUE), can be predicted based on the native habitat and climate (temperature and precipitation) of each study species. All of the species studied naturally occur in humid tropical or subtropical climate zones where precipitation varies widely from ~400 - 3000 mm per year. We found Jacaranda (Jacaranda chelonia) and honey locust (Gleditsia triacanthos) to have the highest photosynthesis and reference (at VPD=1 kPa) conductance, and to be most sensitive to VPD. WUE was found to be greatest in Indian laurel fig (Ficus microcarpa), rose gum (Eucalyptus grandis) and Queensland lacebark (Brachychiton discolor). The relative ordering of maximum photosynthesis and conductance across species was not entirely predictable based on our current knowledge of the native habitats of each species: several other species had similar native climates to Jacaranda and honey locust, yet had lower photosynthesis and conductance. However, WUE generally followed the expected trends, with species predicted to have low conductance showing higher WUE. This implies that WUE is strongly genetically controlled and may be predictable with knowledge of imported species' native habitat. Other traits, such as leaf nitrogen and isotopes, are also being investigated as proxies for detailed gas exchange measurements in this ecosystem. Further refinement of predictive factors will facilitate conceptual and quantitative models that can be used for robust scaling of water and carbon fluxes from trees to urban regions.

McCarthy, H. R.; Jenerette, G. D.; Pataki, D. E.

2008-12-01

364

Development of an Evaporation Prediction Model for Open Water Bodies of South Carolina and Similar Regions.  

National Technical Information Service (NTIS)

The purpose of this study is to upgrade the predictive capability for evaporation in South Carolina and in similar geographical regions and to present the results in a manner which can be used for water resource planning. The final product is a menu-drive...

J. L. Reck W. T. Robinson B. L. Sill

1995-01-01

365

Can site-specific heuristic toxicity models predict the toxicity of produced water?  

PubMed

An empirically derived model of major ion toxicity was combined with other toxicity assessments to account for the observed toxicity in field-collected produced water and produced water contaminated groundwater. The accuracy and precision of the ion toxicity model, calculated using model deviation ratios (MDR) and simple linear regressions, was determined for fathead minnows, Ceriodaphnia dubia, and Daphnia magna. Model accuracy for produced water fell within a factor of two for all three organisms. The precision, or variability explained by the model, was 47.9%, 56.1%, and 0.00% for fathead minnows, C. dubia, and D. magna, respectively. Incorporating other measured potential toxicants improved predictive precision for fathead minnows to 67.0% using ion toxicity and pH and to 30.9% for D. magna using ion toxicity, pH, and total ammonia. The observed toxicity to Daphnia pulex was also evaluated using D. magna model predictions and other measured parameters, but no consistent relationship was found. Dissimilar results were found for produced water contaminated groundwaters with model predictions for D. magna falling within a factor of two of and explaining 53.8% of the observed variability in D. pulex responses. These results indicate that predicted major ion toxicity, combined with other measured parameters, can accurately and precisely account for observed responses in test organisms to field-collected samples. PMID:20466406

Fisher, Jonathan C; Belden, Jason B; Bidwell, Joseph R

2010-05-13

366

GPS-Meterology: Impact of predicted orbits on precipitable water estimates  

NASA Astrophysics Data System (ADS)

Studies of atmospheric effects on Global Positioning System (GPS) signals have proven the possibility of deriving the total water vapor content from estimates of tropospheric path delays. The accuracy of GPS derived Precipitable Water (PW) depends (besides other parameters) on the quality of satellite orbits used in the analysis. High precision orbits provided by the International GPS Service (IGS) yield PW estimates with an accuracy of about 1 mm. While these orbits are provided with a delay of several days, weather forecasting requires near real-time determination of PW. Therefore operational meteorological GPS analysis would have to rely on orbit predictions. We investigate the impact of introducing predicted orbit information on the accuracy of GPS water vapor retrievals. The presented data were acquired during a 14-day field experiment carried out in the north-west region of Madrid, Spain using GPS and a Water Vapor Radiometer (WVR). The comparison of WVR measurements with estimated time series of PW using both 24 and 48 hour predicted orbits and final precise IGS orbits shows that the accuracy of PW decreases by a factor of about 2 from precise to predicted orbit data.

Kruse, Lars Peter; Sierk, Bernd; Springer, Tim; Cocard, Marc

1999-07-01

367

GPS-meteorology: Impact of predicted orbits on precipitable water estimates  

NASA Astrophysics Data System (ADS)

Studies of atmospheric effects on Global Positioning System (GPS) signals have proven the possibility of deriving the total water vapor content from estimates of tropospheric path delays. The accuracy of GPS derived Precipitable Water (PW) depends (besides other parameters) on the quality of satellite orbits used in the analysis. High precision orbits provided by the International GPS Service (IGS) yield PW estimates with an accuracy of about 1 mm. While these orbits are provided with a delay of several days, weather forecasting requires near real-time determination of PW. Therefore operational meteorological GPS analysis would have to rely on orbit predictions. We investigate the impact of introducing predicted orbit information on the accuracy of GPS water vapor retrievals. The presented data were acquired during a 14-day field experiment carried out in the north-west region of Madrid, Spain using GPS and a Water Vapor Radiometer (WVR). The comparison of WVR measurements with estimated time series of PW using both 24 and 48 hour predicted orbits and final precise IGS orbits shows that the accuracy of PW decreases by a factor of about 2 from precise to predicted orbit data.

Peter Kruse, Lars; Sierk, Bernd; Springer, Tim; Cocard, Marc

1999-07-01

368

PREDICTION OF OCTANOL/WATER PARTITION COEFFICIENT (KOW) WITH ALGORITHMICALLY DERIVED VARIABLES  

EPA Science Inventory

A statistical model was developed with algorithmically derived independent variables based on chemical structure for prediction of octanol/water partition coefficients (Kow) measured for more than 4,000 chemicals. he procedure first classified the chemicals into 14 groups based o...

369

A field test of a conceptual computer simulation model for predicting water and salt distribution  

Microsoft Academic Search

The unsaturated flow and unsaturated chemistry submodels of a conceptual computer simulation model, developed at the United States Bureau of Reclamation to predict water and salt behaviour in soils, were tested under field conditions. The comparison of results was done with data obtained from an irrigation trial with alfalfa over a period of four years. The model simulated the actual

J. H. Moolman; D. J. Beukes

1980-01-01

370

Thermosiphon solar domestic water heating systems: long-term performance prediction using artificial neural networks  

Microsoft Academic Search

The objective of this work is to use artificial neural networks (ANN) for the long-term performance prediction of thermosiphonic type solar domestic water heating (SDWH) systems. Thirty SDWH systems have been tested and modelled according to the procedures outlined in the standard ISO 9459-2 at three locations in Greece. From these, data from 27 of the systems were used for

Soteris A Kalogirou; Sofia Panteliou

2000-01-01

371

Five Years Later: Predicting Student Use of Journals in a New Water Resources Graduate Program  

ERIC Educational Resources Information Center

|Using citation analysis, the authors examined the journals cited in theses and dissertations over the first five years of the Water Resources Graduate Program at Oregon State University. These journal titles were compared to the titles predicted as being important in the 2003 Oregon State University Libraries new program (Category I) review. A…

Wirth, Andrea A.; Mellinger, Margaret

2011-01-01

372

Five Years Later: Predicting Student Use of Journals in a New Water Resources Graduate Program  

ERIC Educational Resources Information Center

Using citation analysis, the authors examined the journals cited in theses and dissertations over the first five years of the Water Resources Graduate Program at Oregon State University. These journal titles were compared to the titles predicted as being important in the 2003 Oregon State University Libraries new program (Category I) review. A…

Wirth, Andrea A.; Mellinger, Margaret

2011-01-01

373

Predicting the Frequency of Water Quality Standard Violations Using Bayesian Calibration of Eutrophication Models  

Microsoft Academic Search

The water quality standard setting process usually relies on mathematical models with strong mechanistic basis, as this provides assurance that the model will more realistically project the effects of alternative management schemes. From an operational standpoint, the interpretation of model results should be coupled with rigorous error analysis and explicit consideration of the predictive uncertainty and natural variability. In this

Weitao Zhang; George B. Arhonditsis

2008-01-01

374

Optical Properties of Three Beach Waters: Implications for Predictive Modeling of Enterococci  

EPA Science Inventory

Sunlight plays an important role in the inactivation of fecal indicator bacteria in recreational waters. Solar radiation can explain temporal trends in bacterial counts and is commonly used as an explanatory variable in predictive models. Broadband surface radiation provides a ba...

375

Combining ARS Process-Based Water and Wind Erosion Prediction Technologies  

Technology Transfer Automated Retrieval System (TEKTRAN)

Erosion process research in the United States has long been separated by location, experimental data collection, and prediction technologies. Erosion experiment stations were established in the l930’s throughout the country, however most examined erosion by water while a few in the Plains states we...

376

Performance of pedotransfer functions in predicting soil water characteristics of soils in Norway  

Microsoft Academic Search

Pedotransfer functions (PTFs), predicting the soil water retention curve (SWRC) from basic soil physical properties, need to be validated on arable soils in Norway. In this study we compared the performance of PTFs developed by Riley (1996), Rawls and Brakensiek (1989), Vereecken et al. (1989), Wösten et al. (1999) and Schaap et al. (2001). We compared SWRCs calculated using textural

Sigrun Hjalmarsdottir Kværnø; Lars Egil Haugen

2011-01-01

377

COMPARISON OF MODEL PREDICTIONS AND CONSUMPTIVE WATER USE OF CLOSED CYCLE COOLING SYSTEMS  

EPA Science Inventory

The report gives results of a comparison of field-data-derived water evaporation rates with predictive model values for cooling towers and cooling ponds at steam-electric generating plants. The Leung Moore cooling tower model and five cooling pond models (Harbeck and Marciano; Ha...

378

Temporal and spatial controls on variability in water repellency for prediction of runoff from burned watersheds  

Microsoft Academic Search

Prediction of runoff in catchments affected by wildfire is an extreme example of the ungauged basin problem. After wildfire, there is an increase in the risk of severe erosion, floods, and debris flows, often resulting from water repellency. The transient nature of wildfire effects on soils makes the gauging information from affected systems anecdotal in nature; so modeling is required

C. Luce

2004-01-01

379

Water Wizards: School Program on Water Conservation for Third and Fourth Grade Levels.  

ERIC Educational Resources Information Center

|Water is precious. It is also easy to take for granted. Many people recognize that water is scarce in desert areas. but it is harder to realize that places like Massachusetts could face a shortage of pure drinking water. This manual provides teachers with curriculum resources to introduce concepts of water supply and water conservation to third…

Massachusetts State Water Resources Authority, Boston.

380

Predicting tree-level forest structure from LiDAR data  

NASA Astrophysics Data System (ADS)

This research evaluates the efficacy of statistical imputation models (e.g., the k-nearest neighbor algorithm) incorporating LiDAR data to predict and map tree-level forest structure data (individual tree height, diameter at breast height, and species) across an 88,000 ha study area in Northern Idaho, USA. The primary objective is to provide spatially explicit data to parameterize the Forest Vegetation Simulator (FVS), a forest growth model that operates at the individual tree level, so that forest growth can be modeled across the entire study area. In addition to FVS parameterization, the imputed forest structure data could be used for many purposes including forest commodity assessment, carbon accounting, wildlife habitat modeling, etc. The final imputation models utilize LiDAR derived intensity and height measurements as well as LiDAR DEM topographic variables, to predict tree- level forest structure data. The imputed forest structure data are compared to independent ground-based forest inventory data via statistical equivalence models. Initial results indicate that the imputed data are equivalent (± 15 %) to the independent forest inventory data. Further development of this method will provide tree- level forest inventory data across large spatial extents.

Falkowski, M. J.; Gessler, P. E.; Hudak, A. T.; Crookston, N. L.

2007-12-01

381

Rock motion simulation and prediction of porosity distribution for a two-void-level retort  

SciTech Connect

The computer program DMC (Distinct Motion Code) was developed in 1988 and 1989 to predict the motion of rock following a conventional blast. The ability to predict the rock motion associated with oil shale retort blasting, along with the induced porosity distribution, has been a driving force behind the development of DMC. Earlier this year DMC was used to simulate the rock motion associated with the rubblization of Occidental Oil Shale's Retort Number 8 which was a three-void-level retort processed in 1982. This paper discusses the algorithm developed to compute the porosity distribution of the muck after rock motion. It also contains a simulation of a two-void-level retort rubblization plan proposed by Ricketts, 1989. DMC is used to model the rock motion associated with the blasting and to obtain a final porosity distribution. Some improvement in the porosity distribution is seen over that observed in the three-void-level simulation. Thus, it may be that the two-void-level approach is not only more efficient to mine, but may also produce a more uniform rubble bed. 8 refs., 12 figs.

Preece, D.S.

1990-01-01

382

Determination of Vibrational and Rotational Energy Levels of Water Vapor.  

National Technical Information Service (NTIS)

Water vapor absorbs energy in the infrared and invisible portions of the electromagnetic spectrum by two methods: Absorption of energy to increase its vibrational energy and/or absorption of energy to increase its rotational energy. Computer programs were...

D. L. Dobbins A. H. LaGrone

1967-01-01

383

Analysis of water levels in the Frenchman Flat area, Nevada Test Site  

USGS Publications Warehouse

Analysis of water levels in 21 wells in the Frenchman Flat area, Nevada Test Site, provides information on the accuracy of hydraulic-head calculations, temporal water-level trends, and potential causes of water-level fluctuations. Accurate hydraulic heads are particularly important in Frenchman Flat where the hydraulic gradients are relatively flat (less than 1 foot per mile) in the alluvial aquifer. Temporal water-level trends with magnitudes near or exceeding the regional hydraulic gradient may have a substantial effect on ground-water flow directions. Water-level measurements can be adjusted for the effects of barometric pressure, formation water density (from water-temperature measurements), borehole deviation, and land-surface altitude in selected wells in the Frenchman Flat area. Water levels in one well were adjusted for the effect of density; this adjustment was significantly greater (about 17 feet) than the adjustment of water levels for barometric pressure, borehole deviation, or land-surface altitude (less than about 4 feet). Water-level measurements from five wells exhibited trends that were statistically and hydrologically significant. Statistically significant water-level trends were observed for three wells completed in the alluvial aquifer (WW-5a, UE-5n, and PW-3), for one well completed in the carbonate aquifer (SM-23), and for one well completed in the quartzite confining unit (Army-6a). Potential causes of water-level fluctuations in wells in the Frenchman Flat area include changes in atmospheric conditions (precipitation and barometric pressure), Earth tides, seismic activity, past underground nuclear testing, and nearby pumping. Periodic water-level measurements in some wells completed in the carbonate aquifer indicate cyclic-type water-level fluctuations that generally correlate with longer term changes (more than 5 years) in precipitation. Ground-water pumping fromthe alluvial aquifer at well WW-5c and pumping and discharge from well RNM-2s appear to cause water-level fluctuations in nearby observation wells. The remaining known sources of water-level fluctuations do not appear to substantially affect water-level changes (seismic activity and underground nuclear testing) or do not affect changes over a period of more than 1 year (barometric pressure and Earth tides) in wells in the Frenchman Flat area.

Bright, D. J.; Watkins, S. A.; Lisle, B. A.

2001-01-01

384

Use of artificial neural networks for predicting optimal alum doses and treated water quality parameters  

Microsoft Academic Search

Coagulation is an important component of water treatment. Determination of optimal coagulant doses is vital, as insufficient dosing will result in undesirable treated water quality. On the other hand, doses that are too high can result in high cost and health problems related to high levels of residual aluminium (if alum is used as the coagulant). Traditionally, jar tests are

Holger R. Maier; Nicolas Morgan; Christopher W. K. Chow

2004-01-01

385

A computational model to predict changes in breathiness resulting from variations in aspiration noise level  

PubMed Central

Perception of breathy voice quality is cued by a number of acoustic changes including an increase in aspiration noise level (AH) and spectral slope[1]. Changes in AH in a vowel may be evaluated through measures such as the harmonic-to-noise ratio (HNR), cepstral peak prominence (CPP) or via auditory measures such as the partial loudness of harmonic energy (PL) and loudness of aspiration noise (NL). Although a number of experiments have reported high correlation between such measures and ratings of perceived breathiness, a formal model to predict breathiness of a vowel has not been proposed. This research describes two computational models to predict changes in breathiness resulting from variations in AH. One model uses auditory measures while the other uses CPP as independent variables to predict breathiness. For both cases, a translated and truncated power function is required to predict breathiness. Some parameters in both of these models were observed to be pitch-dependent. The “unified” model based on auditory measures was observed to be more accurate than one based on CPP.

Shrivastav, Rahul; Camacho, Arturo

2009-01-01

386

26. JUNCTION STRUCTURE. WATER LEVEL 1190FT, INNER RING MIXER OF ...  

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

26. JUNCTION STRUCTURE. WATER LEVEL 1190FT, INNER RING MIXER OF STATE AND COLORADO, WATER EXITS THROUGH OUTER RING. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

387

Potential Variation of Great Lakes Water Levels: A Hydrologic Response Analysis.  

National Technical Information Service (NTIS)

The potential for water level changes on Lakes Michigan, Huron, St. Clair, and Erie is examined, using the Great Lakes Environmental Research Laboratory's Hydrologic Response Model (HRM) in conjunction with several hydrometeorologic and water management s...

H. C. Hartmann

1988-01-01

388

Centimeter-Scale Changes in Water Levels Beneath Flooded Vegetation Measured With Interferometric SAR  

Microsoft Academic Search

Interferometric processing of both SIR-C and JERS-1 synthetic aperture radar (SAR) data yields phase measurements indicative of subtle water level changes beneath flooded vegetation. Open water produces specular radar reflections however, inundated vegetation allows a \\

D. Alsdorf

2001-01-01

389

Growth and Food Consumption by Tiger Muskellunge: Effects of Temperature and Ration Level on Bioenergetic Model Predictions  

Microsoft Academic Search

We measured growth of age-0 tiger muskellunge as a function of ration size (25, 50, 75, and 100% Cmax) and water temperature (7.5-258C) and compared experimental results with those predicted from a bioenergetic model. Discrepancies between actual and predicted values varied appreciably with water temperature and growth rate. On average, model output overestimated winter consumption rates at 10 and 7.58C

Steven R. Chipps; Lisa M. Einfalt; David H. Wahl

2000-01-01

390

Growth and Food Consumption by Tiger Muskellunge: Effects of Temperature and Ration Level on Bioenergetic Model Predictions  

Microsoft Academic Search

We measured growth of age-0 tiger muskellunge as a function of ration size (25, 50, 75, and 100% Cmax) and water temperature (7.5–25°C) and compared experimental results with those predicted from a bioenergetic model. Discrepancies between actual and predicted values varied appreciably with water temperature and growth rate. On average, model output overestimated winter consumption rates at 10 and 7.5°C

Steven R. Chipps; Lisa M. Einfalt; David H. Wahl

2000-01-01

391

Stochastic modeling of Lake Van water level time series with jumps and multiple trends  

NASA Astrophysics Data System (ADS)

In the 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey, has risen up about 2 m. Analysis of the hydrometeorological data shows that change in the water level is related to the water budget of the lake. In this study, stochastic models are proposed for simulating monthly water level data. Two models considering mono- and multiple-trend time series are developed. The models are derived after removal of trend and periodicity in the dataset. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. In the so-called mono-trend model, the time series is treated as a whole under the hypothesis that the lake water level has an increasing trend. In the second model (so-called multiple-trend), the time series is divided into a number of segments to each a linear trend can be fitted separately. Application on the lake water level data shows that four segments, each fitted with a trend line, are meaningful. Both the mono- and multiple-trend models are used for simulation of synthetic lake water level time series under the hypothesis that the observed mono- and multiple-trend structure of the lake water level persist during the simulation period. The multiple-trend model is found better for planning the future infrastructural projects in surrounding areas of the lake as it generates higher maxima for the simulated lake water level.

Aksoy, H.; Unal, N. E.; Eris, E.; Yuce, M. I.

2013-06-01

392

Plasma levels of angiopoietin-1 and -2 predict cerebral malaria outcome in Central India  

PubMed Central

Background The mechanisms underlying the pathogenesis of cerebral malaria (CM) syndrome are not well understood. Previous studies have shown a strong association of inflammatory chemokines, apoptotic markers and angiogenic molecules with CM associated mortality. Recognizing the importance of angiopoietins (ANG) in the pathogenesis of CM, a retrospective investigation was carried out in a hospital cohort of malaria patients with Plasmodium infection in central India to determine if these factors could be suitable markers of CM associated severity. Methods Patients enrolled in the study were clinically characterized as healthy controls (HC), mild malaria (MM), CM survivors (CMS) and CM non-survivors (CMNS) based on their malaria status and hospital treatment outcome. Plasma ANG-1 and ANG-2 levels were assessed using sandwich ELISA. Receiver operating characteristic (ROC) curve analysis was used to calculate area under the curve (AUC) for each biomarker in order to assess predictive accuracy of individual biomarkers. Results The plasma levels of ANG-1 were lower in CMS and CMNS compared to control groups (mild malaria and healthy controls) at the time of hospital admission. On the contrary, ANG-2 levels positively correlated with malaria severity and were significantly higher in CMNS. The ratio of ANG-2/ANG-1 was highest in CMNS compared to other groups. Receiver operating characteristic curves revealed that compared to ANG-1 (AUC = 0.35), ANG-2 (AUC = 0.95) and ratio of ANG-2/ANG-1 (AUC = 0.90) were better markers to discriminate CMNS from MM cases. However, they were less specific in predicting fatal outcome amongst CM cases at the time of hospital admission. Conclusion These results suggest that at the time of admission plasma levels of ANG-2 and ratio of ANG-2/ANG-1 are clinically informative biomarkers to predict fatal CM from MM cases while they have limited usefulness in discriminating fatal CM outcomes in a pool of CM cases in endemic settings of Central India.

2011-01-01

393

Stationary and non-stationary autoregressive processes with external inputs for predicting trends in water quality.  

PubMed

An autoregressive approach for the prediction of water quality trends in systems subject to varying meteorological conditions and short observation periods is discussed. Under these conditions, the dynamics of the system can be reliably forecast, provided their internal processes are understood and characterized independently of the external inputs. A methodology based on stationary and non-stationary autoregressive processes with external inputs (ARX) is proposed to assess and predict trends in hydrosystems which are at risk of contamination by organic and inorganic pollutants, such as pesticides or nutrients. The procedures are exemplified for the transport of atrazine and its main metabolite deethylatrazine in a small agricultural catchment in France. The approach is expected to be of particular value to assess current and future trends in water quality as part of the European Water Framework Directive and Groundwater Directives. PMID:18554747

Pinault, Jean Louis; Dubus, Igor G

2008-05-16

394

Neural network application for radionuclide modelling and prediction of radioactivity levels  

NASA Astrophysics Data System (ADS)

Existing applications of artificial neural networks in physics research and development have been analyzed as a basis for proposing new opportunities using that AI technology for data analysis in physics. A taxonomy was developed, based on an extensive literature search, for physics problems where neural network applications have been useful. Then, a particular use of neural networks was carried out to study ways to predict normal concentrations of radioactivity measured at monitoring stations in different geographic locations. The purpose of the data collection and analysis was to establish background levels that would serve as bases for detecting unusual levels of radioactivity, for example due to nuclear weapons testing, in these physical environments. Useful data sets were developed in this area and a process was discovered for modeling the background levels.

Lynch, Myron Corbett, Jr.

395

Prediction of sound levels in an isolated locomotive cab by the finite element method  

NASA Astrophysics Data System (ADS)

An isolated cab has been developed by the Electro-Motive Division of General Motors for its SD60M locomotive model as a quantum step in reducing cab sound level. A finite element analysis methodology was used to improve the acoustics of the cab during the initial design phase. The analysis was used to identify standing wave resonances in the cab acoustic cavity and to make modifications to the structure so that structural mode shapes do not correspond to the acoustical cavity mode shapes. A coupled acoustical-structural model was developed to predict sound levels within the cab in the 20 to 100 hertz frequency range. Excitation to the model was a vibrational forcing function applied at the isolation mount boundaries and was based on measurements from actual locomotives. A parametric study was performed to determine the effect on cab sound level of variations in absorption coefficients of the interior panels of the cab.

Huang, Mark; Carlson, William

396

Nitrates in drinking water and methemoglobin levels in pregnancy: a longitudinal study  

PubMed Central

Background Private water systems are more likely to have nitrate levels above the maximum contaminant level (MCL). Pregnant women are considered vulnerable to the effects of exposure to high levels of nitrates in drinking water due to their altered physiological states. The level of methemoglobin in the blood is the biomarker often used in research for assessing exposure to nitrates. The objective of this study was to assess methemoglobin levels and examine how various factors affected methemoglobin levels during pregnancy. We also examined whether differences in water use practices existed among pregnant women based on household drinking water source of private vs. public supply. Methods A longitudinal study of 357 pregnant women was conducted. Longitudinal regression models were used to examine changes and predictors of the change in methemoglobin levels over the period of gestation. Results Pregnant women showed a decrease in methemoglobin levels with increasing gestation although <1% had levels above the physiologic normal of 2% methemoglobin, regardless of the source of their drinking water. The multivariable analyses did not show a statistically significant association between methemoglobin levels and the estimated nitrate intake from tap water among pregnant women around 36 weeks gestation (? = 0.046, p = 0.986). Four women had tap water nitrate levels above the MCL of 10 mg/L. At enrollment, a greater proportion of women who reported using water treatment devices were private wells users (66%) compared to public system users (46%) (p < 0.0001). Also, a greater proportion of private well users (27%) compared to public system users (13%) were using devices capable of removing nitrate from water (p < 0.0001). Conclusion Pregnant women potentially exposed to nitrate levels primarily below the MCL for drinking water were unlikely to show methemoglobin levels above the physiologic normal. Water use practices such as the use of treatment devices to remove nitrates varied according to water source and should be considered in the assessment of exposure to nitrates in future studies.

2010-01-01

397

Bath-tub vortex attenuation with the increase of in-vessel water level  

NASA Astrophysics Data System (ADS)

During the study of a bath-tub vortex formed in water flowing out through the hole in a vessel's bottom, a methodology was developed that enables controlling the change of in-vessel water level by continuous replenishment. The controlled rate of replenishment enables not only compensating for the loss of drained water and maintaining it at a constant level, but also increasing such a level. Enhancement of water level at different times after the formation of the bath-tub vortex leads to the gradual extinction of the vortex until its complete disappearance when a certain critical level of water in the vessel is achieved. A bath-tub vortex shape with a decrease of in-vessel water level and increase differs significantly.

Meshkov, E. E.; Sirotkin, A. A.

2013-07-01

398

Computational methodology to predict satellite system-level effects from impacts of untrackable space debris  

NASA Astrophysics Data System (ADS)

This paper presents a computational methodology to predict the satellite system-level effects resulting from impacts of untrackable space debris particles. This approach seeks to improve on traditional risk assessment practices by looking beyond the structural penetration of the satellite and predicting the physical damage to internal components and the associated functional impairment caused by untrackable debris impacts. The proposed method combines a debris flux model with the Schäfer-Ryan-Lambert ballistic limit equation (BLE), which accounts for the inherent shielding of components positioned behind the spacecraft structure wall. Individual debris particle impact trajectories and component shadowing effects are considered and the failure probabilities of individual satellite components as a function of mission time are calculated. These results are correlated to expected functional impairment using a Boolean logic model of the system functional architecture considering the functional dependencies and redundancies within the system.

Welty, N.; Rudolph, M.; Schäfer, F.; Apeldoorn, J.; Janovsky, R.

2013-07-01

399

Predicting vegetation water content in wheat using normalized difference water indices derived from ground measurements.  

PubMed

Vegetation water content (VWC) is an important variable for both agriculture and forest fire management. Remote sensing technology offers an instantaneous and non-destructive method for VWC assessment provided we can relate in situ measurements of VWC to spectral reflectance in a reliable way. In this paper, based on radiative transfer models, three new normalized difference water indices (NDWI) are proposed for VWC [fuel moisture content (FMC), and equivalent water thickness (EWT)] estimation, taking both leaf internal structure and dry matter content into account. Reflectance at 1,200, 1,450 and 1,940 nm were selected and normalized with reflectance at 860 nm to establish three water indices, NDWI(1200), NDWI(1450) and NDWI(1940). Good correlations were observed between FMC (R (2) = 0.65-0.80) and EWT (both at the leaf scale, R (2) = 0.75-0.81 for EWT(L) and at the canopy scale, R (2) = 0.80-0.83 for EWT(C)) at various stages of wheat crop development. PMID:19242776

Wu, Chaoyang; Niu, Zheng; Tang, Quan; Huang, Wenjiang

2009-02-26

400

Suppression of the dynamic transition in surface water at low hydration levels: A study of water on rutile.  

SciTech Connect

Our quasielastic neutron-scattering experiments and molecular-dynamics simulations probing surface water on rutile (TiO{sub 2}) have demonstrated that a sufficiently high hydration level is a prerequisite for the temperature-dependent crossover in the nanosecond dynamics of hydration water. Below the monolayer coverage of mobile surface water, a weak temperature dependence of the relaxation times with no apparent crossover is observed. We associate the dynamic crossover with interlayer jumps of the mobile water molecules, which become possible only at a sufficiently high hydration level.

Mamantov, Gleb M [ORNL; Vlcek, Lukas [ORNL; Wesolowski, David J [ORNL

2009-05-01

401

Ground-water levels beneath eastern Pahute Mesa and vicinity, Nevada Test Site, Nye County, Nevada  

SciTech Connect

This report presents water-level and basic construction data for drill holes in and around the primary are of underground testing on eastern Pahute Mesa, and water-level contours based on the most recent water-level measurement made in each drill hole. Measurements are presented for 72 wells and span about 30 years. The map complements and earlier publication. Information is intended to benefit those involved in: the siting, drilling, and design of drill holes to house nuclear devices, the study of ground water hydrology and radionuclide transport beneath the Pahute Mesa, and investigations of regional ground water flow at and near the NTS.

O`Hagan, M.D.; Laczniak, R.J.

1996-08-01

402

Influence of summer water-level variability on St. Lawrence River-wetland fish assemblages  

USGS Publications Warehouse

Water-level and associated variability are substantial influences on wetland and shallow aquatic communities. The Akwesasne Wetland Complex is an extensive St. Lawrence River system affected by water regulation. The responses of fish assemblages to short-term summer water-level variation were examined throughout this section of the St. Lawrence River and its tributaries. An influence of water-level variability was detected on abundance of three common species [bluntnose minnow (Pimephales notatus), rock bass (Amboplites rupestris), and white sucker (Catastomus commersonii)] and explained 30-44% of variation. This influence has implications for water regulation and natural resource management, and a larger scope evaluation may reveal more extensive effects.

McKenna, Jr. , J. E.; Barkley, J. L.; Johnson, J. H.

2008-01-01

403

[Fluoride levels in commercial dentifrices and drinking water in Algeria].  

PubMed

More and more scientific evidence show that fluorides have a cariostatic action to the plaque-saliva-tooth interface during cariogenous dissolution. Fluorides slow down demineralization and enhance remineralization. Their action is optimal, in the oral environment, when used at low concentrations on a continuous basis. The use of the fluorinated toothpastes during brushing of the teeth is a simple, rational method of daily topics application of fluorine, largely used in the context of prevention of dental caries and which can even be regarded as a public health measure. The water ingestion fluorinated represents itself an excellent average of the local application of fluorine. Our work concerned a quantitative study of fluorine in toothpaste and drinking water, and comparative between the local product and the imported one for the toothpastes, and the mineral water and public supply. The standard method of fluorine based on the potentiometry and distillation has shown that 50% of the tested toothpastes contain adequate concentration so that a product of dental care fights against decay. The Tlemcen tap water contains acceptable fluorine content, but the mineral water, with an excessive contribution, can cause fluorose. Of this, we can deduce that a topical application of a suitable quantity of fluorine on a daily basis in accordance with the precautions is not only the prevention of dental caries, but also to stabilize it if it already exists. PMID:22457989

Merghache, D; Bellout, B; Merghache, S; Boucherit-Atmani, Z

2011-12-01

404

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...  

Code of Federal Regulations, 2010 CFR

...Water-level indicators, water columns, gauge-glass...connections, gauge cocks, and pressure gauges (modifies PG-60...Water-level indicators, water columns, gauge-glass...connections, gauge cocks, and pressure gauges (modifies PG-60). (a) Boiler water level devices....

2010-10-01

405

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...  

Code of Federal Regulations, 2010 CFR

...Water-level indicators, water columns, gauge-glass...connections, gauge cocks, and pressure gauges (modifies PG-60...Water-level indicators, water columns, gauge-glass...connections, gauge cocks, and pressure gauges (modifies PG-60). (a) Boiler water level devices....

2009-10-01

406

Hepcidin levels predict nonresponsiveness to oral iron therapy in patients with iron deficiency anemia.  

PubMed

Levels of hepcidin, a major regulator of iron homeostasis, may identify patients with iron deficiency anemia (IDA) who will not respond to oral iron therapy. In this study, IDA patients underwent a 14-day trial (run-in) course of ferrous sulfate therapy. Nonresponders (Hgb increase <1 g/dL with 67% compliance rate) were randomized to IV ferric carboxymaltose (FCM; two injections of 750 mg) or further oral iron for 14 days. Screening hepcidin levels were 38.4 versus 11.3 ng/mL, P = 0.0002 in nonresponders versus responders to a trial of oral iron. Hepcidin of > 20 ng/mL, showed sensitivity of 41.3%, specificity of 84.4%, and positive predictive value of 81.6% for predicting nonresponsiveness to oral iron. PPVs for ferritin> 30 ng/mL or transferrin saturation (TSAT)>15% were 59.2 and 55%, respectively. Negative predictive values for hepcidin, ferritin, and TSAT were 46.3, 22.7, and 19.7, respectively. FCM versus oral iron showed Hgb increases of ? 1 gm/dL in 65.3% versus 20.8% (P < 0.0001) and Hgb increases of 1.7 ± 1.3 versus 0.6 ± 0.9 g/dL (P = 0.0025), respectively. We conclude that hepcidin predicts nonresponsiveness to oral iron in patients with IDA and is superior to TSAT or ferritin for this purpose. Nonresponse to oral iron therapy does not rule out IDA, since two-thirds of patients subsequently responded to intravenous iron. PMID:23335357

Bregman, David B; Morris, David; Koch, Todd A; He, Andy; Goodnough, Lawrence T

2013-01-18

407

Arsenic levels in ground water and cancer incidence in Idaho: an ecologic study  

Microsoft Academic Search

Purpose  Long-term exposure to arsenic above 50 ?g\\/L in drinking water has been related to multiple types of cancers. Few epidemiologic\\u000a studies conducted in the US have detected an association between regional exposures below this level in drinking water and\\u000a corresponding cancer occurrence rates. This county-level ecologic study evaluates arsenic levels in ground water and its association\\u000a with targeted cancer incidence in

Yueh-Ying Han; Joel L. Weissfeld; Devra L. Davis; Evelyn O. Talbott

2009-01-01

408

Hydroclimatic Factors of the Recent Record Drop in Laurentian Great Lakes Water Levels  

Microsoft Academic Search

An extreme low-water supply episode from 1997 to 2000 resulted in the largest 1-yr drop in Lakes Michigan Huron and Lake Erie water levels (0.92 and 1.03 m, respectively) recorded since measurements began in the early 1800s. Lake Superior water levels were the lowest since 1925. Lakes Erie and Ontario also had relatively low levels. The episode was unusual, particularly

Raymond A. Assel; Frank H. Quinn; Cynthia E. Sellinger

2004-01-01

409

Forming conditions and probable values of maximum water levels of the Lena River near Yakutsk  

Microsoft Academic Search

The genesis of the formation of maximum water levels of the Lena River near Yakutsk is considered. Recovery techniques of\\u000a series of hydrological characteristics is briefly stated. Observational data on maximum water levels are reduced to the long-term\\u000a period, an estimation of their homogeneity and stationarity is carried out. The recomputation of maximum water levels of 1%\\u000a probability taking account

A. V. Rozhdestvenskii; V. A. Buzin; T. L. Shalashina

2010-01-01

410

Predicting Trigger Level for Ice Jam Flooding of the lower Mohawk River using LiDAR and GIS  

NASA Astrophysics Data System (ADS)

Ice jams are an annual occurrence along the Mohawk River in upstate New York. The jams commonly result in significant flooding especially when the progress of the ice is impeded by obstructions to the channel and flood plain. To minimize flooding hazards it is critical to know the trigger level of flooding so that we can better understand chronic jam points and simulate flooding events as jams occur as the lower Mohawk. A better understanding of jamming and trigger points may facilitate measures to reduce flooding and avoid the costly damage associated with these hazards. To determine the flood trigger level for one segment of the lower Mohawk we used Air-LiDAR elevation data to construct a digital elevation model to simulate a flooding event. The water flood simulation using a LiDAR elevation model allows accurate water level measurements for determining trigger levels of ice dam flooding. The study area comprises three sections of the lower Mohawk River from the (Before location) to the (After location), which are constrained by lock stations centered at the New York State Canal System Lock 9 (E9 Lock) and the B&M Rail Bridge at the Schenectady International (SI) Plant. This area is notorious for ice jams including one that resulted in a major flooding event on January 25th, 2010 which resulted in flood levels at 74.4 m in the upper portion of the second section of the study area (Lock 9) and at 73.4 m in the lower portion (SI plant). Minimum and maximum elevation levels were found to determine the values at which up stream water builds up and when flooding occurs. From these values, we are able to predict the flooding as the ice jam builds up and breaks as it progresses downstream. Similar methodology is applied to find the trigger points for flooding along other sections of the Mohawk River constrained by lock stations, and it may provide critical knowledge as to how to better manage the hazard of flooding due to ice jams.

Foster, J.; Marsellos, A.; Garver, J.

2011-12-01

411

ClogP(alk): a method for predicting alkane/water partition coefficient.  

PubMed

Alkane/water partition coefficients (P(alk)) are less familiar to the molecular design community than their 1-octanol/water equivalents and access to both data and prediction tools is much more limited. A method for predicting alkane/water partition coefficient from molecular structure is introduced. The basis for the ClogP(alk) model is the strong (R² = 0.987) relationship between alkane/water partition coefficient and molecular surface area (MSA) that was observed for saturated hydrocarbons. The model treats a molecule as a perturbation of a saturated hydrocarbon molecule with the same MSA and uses increments defined for functional groups to quantify the extent to which logP(alk) is perturbed by the introduction each functional group. Interactions between functional groups, such as intramolecular hydrogen bonds are also parameterized within a perturbation framework. The functional groups and interactions between them are specified substructurally in a transparent and reproducible manner using SMARTS notation. The ClogP(alk) model was parameterized using data measured for structurally prototypical compounds that dominate the literature on alkane/water partition coefficients and then validated using an external test set of 100 alkane/water logP measurements, the majority of which were for drugs. PMID:23737238

Kenny, Peter W; Montanari, Carlos A; Prokopczyk, Igor M

2013-06-05

412

A revised land hydrology in the ECMWF model: A step towards water fluxes prediction in a fully-closed water cycle  

Microsoft Academic Search

Predictions of the global water cycle involve accurate atmospheric analyses and forecasts and a realistic representation of land surface processes for correctly timing water recirculation. A river routing mechanism is then needed to simulate rivers transport back into the oceans. Physical parameterizations of the ECMWF Integrated Forecast System (IFS) involved in the predictions of soil moisture and snow have been

G. Balsamo; E. Dutra; F. Pappenberger; P. Viterbo; B. van den Hurk

2009-01-01

413

An Analysis of the International Great Lakes Levels Board Report on Regulation of Great Lakes Water Levels. Hydrology.  

National Technical Information Service (NTIS)

The regulation of water levels in the Great Lakes is a subject that has recently received much attention by the states directly affected by lake level fluctuations. This report deals with the hydrology of the Great Lakes system and lays the foundation for...

J. Knox C. Falkner P. Neuman S. Rettig S. Skavroneck

1976-01-01

414

Water level observations in mangrove swamps during two hurricanes in Florida  

USGS Publications Warehouse

Little is known about the effectiveness of mangroves in suppressing water level heights during landfall of tropical storms and hurricanes. Recent hurricane strikes along the Gulf Coast of the United States have impacted wetland integrity in some areas and hastened the need to understand how and to what degree coastal forested wetlands confer protection by reducing the height of peak water level. In recent years, U.S. Geological Survey Gulf Coast research projects in Florida have instrumented mangrove sites with continuous water level recorders. Our ad hoc network of water level recorders documented the rise, peak, and fall of water levels (?? 0.5 hr) from two hurricane events in 2004 and 2005. Reduction of peak water level heights from relatively in-line gages associated with one storm surge event indicated that mangrove wetlands can reduce water level height by as much as 9.4 cm/km inland over intact, relatively unchannelized expanses. During the other event, reductions were slightly less for mangroves along a river corridor. Estimates of water level attenuation were within the range reported in the literature but erred on the conservative side. These synoptic data from single storm events indicate that intact mangroves may support a protective role in reducing maximum water level height associated with surge. ?? 2009 The Society of Wetland Scientists.

Krauss, K. W.; Doyle, T. W.; Doyle, T. J.; Swarzenski, C. M.; From, A. S.; Day, R. H.; Conner, W. H.

2009-01-01

415

Water mass change in the Amazon basin estimated by multi-temporal SAR data, GRACE gravimetry and water level observations  

NASA Astrophysics Data System (ADS)

The 2007 IPCC assessment report identified the land hydrology as one of the most uncertain components of the global water cycle. Variations of continental water masses occur in several compartments (e.g. surface and soil water, snow/ice, and groundwater). Mass variations and related changes of surface water exten-sions are being observed by contemporary space and in-situ observation systems such as GRACE gravim-etry, altimetry, optical/infrared sensors, SAR/InSAR, and in-situ river gauges. In this session we will present a regional multi-sensor study in the Amazon basin. The study focuses on the quantification of variations of water mass and water surface extent caused by extreme flood and drought situations that were frequent during the last decade. PALSAR data of two extreme events was selected; once when the Amazon River was flooded (March/April 2009) and once when the region suffered from a se-vere drought (October/November 2009). The advantage of using PALSAR is that it operates in L-Band and has the possibility to penetrate through the vegetation which is essential in the Amazon basin with its dense vegetation. Time series of water level variations were obtained from two in-situ gauges at Manacapuru and Obidos as well as from Envisat satellite altimetry. Total water storage change in the whole region was given by GRACE gravimetry. First, the variation of water mass is computed numerically using GRACE. Second the water level variations obtained from the two river gauges are analyzed with respect to observation of Envisat. Third the surface water extent is estimated by extracting water masks from PALSAR image data. The water mass change is obtained by intersecting the water masks with a medium resolution digital elevation model (SRTM). More specifically, water heights along the boundary of the river body were extracted from the DEM and processed for error reduction. Then, pixel heights within the river contour were interpolated with a Delaunay triangula-tion. Multiplying the differences in heights between high and low water periods by the area of the DEM reso-lution cell and summing them up over the river area provided an estimate of the total volume change. In the end, the presentation will give an assessment of the spatio-temporal consistency of the different ob-servation systems by comparing the spatial patterns of water variability in the data sets with respect to their temporal development and existing phase lags. Based on the level of consistency we will provide an outlook on the applicability of measurements of water levels and surface water extent for an independent assess-ment of water mass variations.

Spiridonova, S.; Seitz, F.; Hedman, K.; Meyer, F.

2012-04-01

416

A new model for predicting relative nonwetting phase permeability from soil water retention curves  

NASA Astrophysics Data System (ADS)

Relative permeability of the nonwetting phase in a multiphase flow in porous media is a function of phase saturation. Specific expressions of this function are commonly determined by combining soil water retention curves with relative nonwetting phase permeability models. Experimental evidence suggests that the relative permeability of the nonwetting phase can be significantly overestimated by the existing relative permeability models. A new model for the prediction of relative nonwetting phase permeability from soil water retention curves is proposed in this paper. A closed form expression can be obtained in combination with soil water retention curves. The model is mathematically simple and can easily and efficiently be implemented in numerical models of multiphase flow processes in porous media. The predicting capability of the proposed model is contrasted with well-supported models by comparing the measured and predicted relative air permeability data for 11 soils, representing a wide range of soil textures, from sand to silty clay loam. In most of the cases the proposed model improves the agreement between the predicted relative air permeability and the measured data.

Kuang, Xingxing; Jiao, Jiu Jimmy

2011-08-01

417

A comparison of radiosity with current methods of sound level prediction in commercial spaces  

NASA Astrophysics Data System (ADS)

The ray tracing and image methods (and variations thereof) are widely used for the computation of sound fields in architectural spaces. The ray tracing and image methods are best suited for spaces with mostly specular reflecting surfaces. The radiosity method, a method based on solving a system of energy balance equations, is best applied to spaces with mainly diffusely reflective surfaces. Because very few spaces are either purely specular or purely diffuse, all methods must deal with both types of reflecting surfaces. A comparison of the radiosity method to other methods for the prediction of sound levels in commercial environments is presented. [Work supported by NSF.

Beamer, C. Walter, IV; Muehleisen, Ralph T.

2002-11-01

418

Serum alpha-fetoprotein level independently predicts posttransplant survival in patients with hepatocellular carcinoma.  

PubMed

We aimed to determine whether combining serum alpha-fetoprotein (AFP) level with hepatocellular carcinoma (HCC) tumor burden would allow better stratification of posttransplant survival for patients with HCC undergoing liver transplantation. Adjusting for donor and recipient characteristics, we calculated the risk of posttransplant mortality associated with serum AFP level or HCC tumor burden for all first-time adult liver transplants performed in the United States between 2002 and 2011 (n?=?45,267). Serum AFP level, rather than tumor burden, was the tumor characteristic most strongly associated with posttransplant survival. Although recipients with HCC and a serum AFP level???15 ng/mL at the time of transplantation had no excess posttransplant mortality [adjusted hazard ratio (AHR)?=?1.02, 95% confidence interval (CI)?=?0.93-1.12], patients with a serum AFP level of 16 to 65 ng/mL (AHR?=?1.38, 95% CI?=?1.23-1.54), patients with a serum AFP level of 66 to 320 ng/mL (AHR?=?1.65, 95% CI?=?1.45-1.88), and patients with a serum AFP level?>?320 ng/mL (AHR?=?2.37, 95% CI?=?2.06-2.73) had progressively worse posttransplant mortality in comparison with recipients without HCC. Patients with a tumor burden exceeding the Milan criteria (who are usually excluded from transplantation) had excellent posttransplant survival if their serum AFP level was 0 to 15 ng/mL (AHR?=?0.97, 95% CI?=?0.66-1.43). In contrast, patients within the Milan criteria (who are routinely considered to be transplant candidates) had poor survival if their serum AFP level was substantially elevated (for a serum AFP level???66 ng/mL, AHR?=?1.93, 95% CI?=?1.74-2.15). Changes in serum AFP level while patients were on the waiting list corresponded closely to changes in posttransplant mortality. In conclusion, the absolute serum AFP level and changes in the serum AFP level strongly predict posttransplant survival independently of the tumor burden. We hope that these data, in combination with other factors, can be used to inform future studies and ongoing discussions aimed at improving the eligibility criteria for liver transplantation for patients with HCC. PMID:23536495

Berry, Kristin; Ioannou, George N

2013-06-01

419

Applying Water-Level Difference Control to Central Arizona Project  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Central Arizona Project (CAP) has been supplying Colorado River water to Central Arizona for roughly 25 years. The CAP canal is operated remotely with a Supervisory Control and Data Acquisition (SCADA) System. Gate position changes are made either manually or through the use of automatic control...

420

Dissolved Oxygen Levels in New York Bight Waters during 1977.  

National Technical Information Service (NTIS)

Anoxia in bottom waters of the N.Y. Bight, and associated mass mortalities of marine organisms in 1976, caused concern that anoxia may become a chronic problem in the Bight. The Northeast Fisheries Center, National Marine Fisheries Service, established a ...

F. Steimle

1978-01-01

421

High-level radioactive waste from light-water reactors  

Microsoft Academic Search

The production of radioactive nuclei during the operation of a light-water reactor is traced, and their decay history is followed. The potential environmental impacts of this waste are calculated and shown to be comparable to those of other materials we produce. Assuming deep burial, it is shown that there are important time delays which prevent the waste from reaching the

Bernard Cohen

1977-01-01

422

The response of mire vegetation to water level drawdown  

Microsoft Academic Search

Mires have a significant role in climate change mitigation due to their enormous carbon storage and due to the fluxes of greenhouse gases between ecosystem and the atmosphere. Mire vegetation is controlled by ecohydrology, climate and by the competition of plants on light and nutrients. The water logged conditions create a challenging environment for both vascular plants and bryophytes; therefore

Kirsi Kurki; Jukka Laine; Harri Vasander; Eeva-Stiina Tuittila

2010-01-01

423

Predicted versus measured photosynthetic water-use efficiency of crop stands under dynamically changing field environments.  

PubMed

Water-use efficiency (WUE) is critical in determining the adaptation and productivity of plants in water-limited areas, either under the present climate or future global change. Data on WUE are often highly variable and a unifying and quantitative approach is needed to analyse and predict WUE for different environments. Hsiao has already proposed a set of paradigm equations based on leaf gas exchange for this purpose, calculating WUE (ratio of assimilation to transpiration) relative to the WUE for a chosen reference situation. This study tests the validity and applicability of these equations to cotton and sweet corn stands with full canopies in the open field. Measured were evapotranspiration and downward flux of atmospheric CO2 into the canopy, soil CO2 efflux, canopy temperature, and CO2 and vapour pressure of the air surrounding the canopy. With the measured mean WUE and conditions at midday serving as the reference, WUE for other times was predicted from the air CO2 and water vapour data, intercellular water vapour pressure calculated from canopy temperature, and an assumed ratio of Ci/Ca based on leaf gas-exchange data. Provided that the stomatal response to humidity as it affected the Ci/Ca ratio was accounted for, the equations predicted the moment-by-moment changes in canopy WUE of cotton over daily cycles reasonably well, and also the variation in midday WUE from day-to-day over a 47 d period. The prediction for sweet corn was fairly good for most parts of the day except the early morning. Measurement uncertainties and possible causes of the differences between predicted and measured WUE are discussed. Overall, the results indicate that the equations may be suitable to simulate changes in WUE without upscaling, and also demonstrate clearly the importance of stomatal response to humidity in determining stand WUE in the field. PMID:15448179

Xu, Liu-Kang; Hsiao, Theodore C

2004-09-24

424

RCWIM - an improved global water isotope pattern prediction model using fuzzy climatic clustering regionalization  

NASA Astrophysics Data System (ADS)

Prediction of geospatial H and O isotopic patterns in precipitation has become increasingly important to diverse disciplines beyond hydrology, such as climatology, ecology, food authenticity, and criminal forensics, because these two isotopes of rainwater often control the terrestrial isotopic spatial patterns that facilitate the linkage of products (food, wildlife, water) to origin or movement (food, criminalistics). Currently, spatial water isotopic pattern prediction relies on combined regression and interpolation techniques to create gridded datasets by using data obtained from the Global Network of Isotopes In Precipitation (GNIP). However, current models suffer from two shortcomings: (a) models may have limited covariates and/or parameterization fitted to a global domain, which results in poor predictive outcomes at regional scales, or (b) the spatial domain is intentionally restricted to regional settings, and thereby of little use in providing information at global geospatial scales. Here we present a new global climatically regionalized isotope prediction model which overcomes these limitations through the use of fuzzy clustering of climatic data subsets, allowing us to better identify and customize appropriate covariates and their multiple regression coefficients instead of aiming for a one-size-fits-all global fit (RCWIM - Regionalized Climate Cluster Water Isotope Model). The new model significantly reduces the point-based regression residuals and results in much lower overall isotopic prediction uncertainty, since residuals are interpolated onto the regression surface. The new precipitation ?2H and ?18O isoscape model is available on a global scale at 10 arc-minutes spatial and at monthly, seasonal and annual temporal resolution, and will provide improved predicted stable isotope values used for a growing number of applications. The model further provides a flexible framework for future improvements using regional climatic clustering.

Terzer, Stefan; Araguás-Araguás, Luis; Wassenaar, Leonard I.; Aggarwal, Pradeep K.

2013-04-01

425

Prediction of the boiling temperature and heat flux in sugar water solutions under pool-boiling conditions  

NASA Astrophysics Data System (ADS)

Condensing of a sugar water solution is a widely used production process, especially in food industry. In this study, boiling temperature and heat transfer of different concentration levels of sugar/water solution is experimentally studied. In the experiment, the pool boiling with constant temperature difference between surface and boiling temperature is investigated. Boiling point of sugar/water solution depends on sugar mass concentration and on vapor phase pressure. A function is suggested to calculation the boiling temperature. The experimental data and the calculated values of boiling temperature are compared. The results are verified with previous investigations. It is determined that the heat flux between surface and sugar/water solution while pool boiling displays a linear relation with water mass concentration in the solution. Heat transfer coefficient could be determined in dependency of surface temperature and sugar mass concentration. Furthermore a function is suggested to predict the heat flux for engineering purpose, which is already used in similar form for pure substances.

Özdemir, Mustafa; Pehlivan, Hüseyin

2008-05-01

426

Prediction under Change (PUC): Water, Earth and Biota in the Anthropocene  

NASA Astrophysics Data System (ADS)

The world is facing severe water management challenges, in the context of population growth, degradation of a poorly distributed resource, and the considerable uncertainties posed by the effects of climate change. Sustainable management requires the ability to predict the space-time distribution of water resources, water quality and environmental health, to help balance the needs of both humans and the environment. The rapid rates of change that the water cycle and the environment are likely to experience as a result of increasing human impacts (e.g., climate change, land use and land cover changes) requires that prediction and management frameworks better capture coupling and feedbacks across the built, natural, and social systems that define the sustainability of water resources. As we ponder a changing environment - climate, hydrology, land use, biogeochemical cycles, human dynamics - there is an increasing need now to embrace the long-term evolution of linked sub-systems (climatic, hydrologic, geomorphic, ecological etc., as well as human) through a new generation of conceptual and quantitative models that either explicitly or implicitly include the interactions and feedbacks between these sub-systems. Their co-evolution is driven by exogenous variability imposed on the system by weather, climate and anthropogenic factors, and endogenous variability generated by the sub-systems themselves as a result of certain adaptive evolutionary processes. In this talk I will outline the fundamental issues involved in predictions at long time scales (decades) and large space scales (regions) in a fast changing environment, including significant paradigm shifts in the way we seek the fundamental understanding needed to underpin these predictions, including the need for sustained community efforts.

Sivapalan, M.

2011-12-01

427

Predicting fungal growth: the effect of water activity on Penicillium roqueforti.  

PubMed

The effect of water activity on the colony growth of Penicillium roqueforti is studied by predictive modelling techniques. Measured colony diameter growth curves are fitted to estimate the growth rate and lag phase of the curves. The colony growth rate was modelled by a quadratic function of transformed water activity (a(w)) values, as suggested by Baranyi et al. (Food Microbiol. 10 (1993) 43-59). The lag time was modelled as a function of water activity, by means of the sum of a constant term and a hyperboloid function of a(w) raised to the second power. The lag-phase of Penicillium roqueforti was found insensitive to the water activity in the range of its higher (a(w) > 0.92) values. PMID:10357282

Valík, L; Baranyi, J; Görner, F

1999-03-01

428

Experiment and prediction of fire extinguishment with water mist in an enclosed room  

NASA Astrophysics Data System (ADS)

The correlation between oxygen concentration and fire temperature when fire was extinguished with water mist was theoretically studied. The Semenov theory was applied to analyze the critical condition when fire was extinguished with water mist, from which the correlation could be obtained. The water mist experiments were carried out by varying the fire size, atomizer number, ceiling height, system pressure, and pre-burn time in an enclosed room. The oxygen concentration near the edge of the liquid pool and the fire temperature above the center of the liquid pool were measured. A comparison of the experimental data with the correlation was made under different conditions. The results showed that fire extinguishment was a stochastic process which could be affected by many factors. This theoretical model could predict the correlation between fire temperature and oxygen concentration when fire was extinguished with water mist in an enclosed room and it can also be treated as a critical condition for fire extinguishment.

Zhao, Jianbo; Yang, Lijun

2013-02-01

429

Genomic Risk Models Improve Prediction of Longitudinal Lipid Levels in Children and Young Adults  

PubMed Central

In clinical medicine, lipids are commonly measured biomarkers used to assess an individual’s risk for cardiovascular disease, heart attack, and stroke. Accurately predicting longitudinal lipid levels based on genomic information can inform therapeutic practices and decrease cardiovascular risk by identifying high-risk patients prior to onset. Using genotyped and imputed genetic data from 523 unrelated Caucasian Americans from the Bogalusa Heart Study, surveyed on 4,026 occasions from 4 to 48?years of age, we generated various lipid genomic risk models based on previously reported markers. We observed a significant improvement in prediction over non-genetic risk models in high density lipoprotein cholesterol (increase in the squared correlation between observed and predicted values, ?R2?=?0.032), low density lipoprotein cholesterol (?R2?=?0.053), total cholesterol (?R2?=?0.043), and triglycerides (?R2?=?0.031). Many of our approaches are based on an n-fold cross-validation procedure that are, by design, adaptable to a clinical environment.

Wineinger, Nathan E.; Harper, Andrew; Libiger, Ondrej; Srinivasan, Sathanur R.; Chen, Wei; Berenson, Gerald S.; Schork, Nicholas J.

2013-01-01

430

Water pair potential of near spectroscopic accuracy. II. Vibration-rotation-tunneling levels of the water dimer  

Microsoft Academic Search

Nearly exact six-dimensional quantum calculations of the vibration-rotation-tunneling ~VRT! levels of the water dimer for values of the rotational quantum numbers J and K <2 show that the SAPT-5s water pair potential presented in the preceding paper ~paper I! gives a good representation of the experimental high-resolution far-infrared spectrum of the water dimer. After analyzing the sensitivity of the transition

G. C. Groenenboom; P. E. S. Wormer; A. van der Avoird; E. M. Mas; R. Bukowski; K. Szalewicz

431

Influence of mouth status and water level on the macrophytes in a small temporarily open/closed estuary  

NASA Astrophysics Data System (ADS)

The monthly responses of macrophytes in the East Kleinemonde Estuary were examined in relation to changes in physical factors between March 2006 and March 2007. The East Kleinemonde is a small temporarily open/closed system where the mouth breaches in response to high water levels (>2 m amsl) or following high river inflow. On breaching there is a rapid drop in water level that causes the submerged macrophytes to be exposed and they die as a result of desiccation. Salt marsh plants then establish in the vacant habitat. Correlation analysis showed that water level and duration of inundation influenced macrophyte cover abundance. Inundation for 3 months caused die-back of intertidal salt marsh. Under open and tidal conditions, intertidal salt marsh increased at a maximum monthly expansion rate of 25% change in cover. Supratidal salt marsh expanded at maximum monthly rates of 33% change in cover. Because of its position at a relatively high elevation compared to other vegetation, supratidal salt marsh was only affected by water levels of >1.8 m amsl and only after being inundated for 1-2 months. Submerged macrophytes developed in inundated areas when stable water levels were present for longer than 2 months at a monthly maximum expansion rate of 23% cover change. In this study macrophytes responded quickly to water level fluctuations and indicate that monthly monitoring is needed to provide an understanding of macrophyte response. This is the first study that reports on rates of macrophyte habitat development in temporarily open/closed estuaries. These data can be used in mouth management plans and freshwater requirement studies to predict the growth and establishment of a diversity of macrophyte habitats.

Riddin, T.; Adams, J. B.

2008-08-01

432

Rising water levels and the future of southeastern Louisiana swamp forests  

Microsoft Academic Search

An important factor contributing to the deterioration of wetland forests in Louisiana is increasing water levels resulting\\u000a from eustatic sea-level rise and subsidence. Analyses of long-term water level records from the Barataria and Verret watersheds\\u000a in southeastern Louisiana indicate an apparent sea level rise of about 1-m per century, mainly the result of subsidence. Permanent\\u000a study plots were established in

William H. Conner; Michael Brody

1989-01-01

433

Water Quality, Seasonal Water-Level Changes, 1988-89, and Simulated Effects of Increased Water Use from the Ozark Aquifer Near Branson, Missouri.  

National Technical Information Service (NTIS)

The report presents the results of a study designed to provide a reconnaissance of ground-water quality in the Branson area and to determine whether water levels in the Ozark aquifer are recovering fully in the intervening winter period of lesser water us...

J. L. Imes

1991-01-01

434

Effect of water content on the predictions of the Cloud Rise Module of DELFIC. Master's thesis  

SciTech Connect

The effect of water content on the predictions of the Cloud Rise Module (CRM) of the Defense Land Fallout Information Code, (DELFIC) was examined. Problems with the theory of the CRM were found, especially how it handled the cloud's water content. The source code of the CRM was also found to have some contradictions with its documentation. All of the problems found with the CRM were addressed and a new version of DELFIC was created. This new version was then used to examine the predicted nuclear cloud height and volume for different humidity profiles and surface-water mass loading of the cloud. Increasing the atmospheric humidity resulted in a higher stabilized cloud top altitude and larger volume; increasing the surface water loading resulted in a lower stabilized cloud top and a smaller cloud volume. The effect of soil loading was examined, and found to produce only slight changes in the stabilized cloud top and volume. Results found with the revised CRM were compared to the results found using the original CRM. Both versions followed the same trends as the humidity profiles were changed, but the results found for the surface water loading case were very divergent. The differences in the results of the two versions suggest the results of the revised CRM are more valid.

Minor, B.M.

1988-03-01

435

Serum Cholesterol and Ceruloplasmin Levels in Second Trimester can Predict Development of Pre-eclampsia  

PubMed Central

Background: Pre-eclampsia is one of the leading causes of high rates of maternal and perinatal mortality and morbidity. Pathophysiology of pre-eclampsia is still obscure. Currently, there are no screening tests for pre-eclampsia that are reliable, valid, and economical. Parameters of oxidative stress could be early markers of endothelial dysfunction that predates clinical pre-eclampsia. Aim: This study was to study ceruloplasmin in nulliparous women as marker of oxidative stress and lipid profile to evaluate their value in prediction of pre-eclampsia. Materials and Methods: Prospective observational study. 306 nulliparous women had their serum lipid profile and ceruloplasmin levels measured at 14-16 weeks period of gestation as sample 1 and at 18-20 weeks as sample 2. All cases were followed up till the end of pregnancy for development of pre-eclampsia. Results: There was no statistically significant difference between the normals and pre-eclampsia cases at 14-16 week for all the oxidative stress parameters (P > 0.05), but at 18-20 week, there was statistically significant difference between the normals and pre-eclampsia cases in cholesterol and ceruloplasmin parameters (P < 0.05). Conclusion: Cholesterol and ceruloplasmin levels in second trimester (18-20 weeks) can predict the development of pre-eclampsia.

Dey, Madhusudan; Arora, Devendra; Narayan, Nagarja; Kumar, Reema

2013-01-01

436

A calculator program for clinical application of the Bayesian method of predicting plasma drug levels.  

PubMed

A pharmacokinetic program that allows individualization of drug dosage regimens through the Bayesian method is described. The program, which is designed for the Hewlett-Packard HP-41 CV calculator, is based upon the one-compartment open model with either instantaneous or zero-order absorption. Individualized estimation of the patient's kinetic parameters (clearance and volume of distribution) is performed by analyzing the plasma levels measured in the patient as well as considering the population data of the drug. After estimating the individual kinetic parameters by the Bayesian method, the program predicts the dosage regimen that will elicit the desired peak and trough plasma levels at steady state. For comparison purposes, the least-squares estimates for clearance and volume of distribution are calculated, and dosage prediction can also be made on the basis of the least-squares estimates. The least-squares estimates can be used to calculate population pharmacokinetic parameters according to the Standard Two-Stage method. Several examples of clinical use of the program are presented. The examples refer to patients with classic hemophilia who were treated with Factor VIII concentrates. In these patients, the Bayesian kinetic parameters of Factor VIII have been estimated through the calculator program. The Bayesian parameter estimates generated by the HP-41 have been compared with those determined by a Bayesian program (ADVISE) designed for microcomputers. PMID:3928243

Ruffo, S; Messori, A; Grasela, T H; Longo, G; Donati-Cori, G; Matucci, M; Morfini, M; Tendi, E

1985-01-01

437

SHORT-TERM SOLAR FLARE LEVEL PREDICTION USING A BAYESIAN NETWORK APPROACH  

SciTech Connect

A Bayesian network approach for short-term solar flare level prediction has been proposed based on three sequences of photospheric magnetic field parameters extracted from Solar and Heliospheric Observatory/Michelson Doppler Imager longitudinal magnetograms. The magnetic measures, the maximum horizontal gradient, the length of neutral line, and the number of singular points do not have determinate relationships with solar flares, so the solar flare level prediction is considered as an uncertainty reasoning process modeled by the Bayesian network. The qualitative network structure which describes conditional independent relationships among magnetic field parameters and the quantitative conditional probability tables which determine the probabilistic values for each variable are learned from the data set. Seven sequential features-the maximum, the mean, the root mean square, the standard deviation, the shape factor, the crest factor, and the pulse factor-are extracted to reduce the dimensions of the raw sequences. Two Bayesian network models are built using raw sequential data (BN{sub R}) and feature extracted data (BN{sub F}), respectively. The explanations of these models are consistent with physical analyses of experts. The performances of the BN{sub R} and the BN{sub F} appear comparable with other methods. More importantly, the comprehensibility of the Bayesian network models is better than other methods.

Yu Daren; Huang Xin; Hu Qinghua; Zhou Rui [Harbin Institute of Technology, No. 92 West Da Zhi Street, Harbin, Heilongjiang Province 150001 (China); Wang Huaning [National Astronomical Observatories, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Cui Yanmei, E-mail: huangxinhit@yahoo.com.c [Center for Space Science and Applied Research, No. 1 Nanertiao, Zhongguancun, Haidian District, Beijing 100080 (China)

2010-02-10

438

Short-term Solar Flare Level Prediction Using a Bayesian Network Approach  

NASA Astrophysics Data System (ADS)

A Bayesian network approach for short-term solar flare level prediction has been proposed based on three sequences of photospheric magnetic field parameters extracted from Solar and Heliospheric Observatory/Michelson Doppler Imager longitudinal magnetograms. The magnetic measures, the maximum horizontal gradient, the length of neutral line, and the number of singular points do not have determinate relationships with solar flares, so the solar flare level prediction is considered as an uncertainty reasoning process modeled by the Bayesian network. The qualitative network structure which describes conditional independent relationships among magnetic field parameters and the quantitative conditional probability tables which determine the probabilistic values for each variable are learned from the data set. Seven sequential features—the maximum, the mean, the root mean square, the standard deviation, the shape factor, the crest factor, and the pulse factor—are extracted to reduce the dimensions of the raw sequences. Two Bayesian network models are built using raw sequential data (BN_R) and feature extracted data (BN_F), respectively. The explanations of these models are consistent with physical analyses of experts. The performances of the BN_R and the BN_F appear comparable with other methods. More importantly, the comprehensibility of the Bayesian network models is better than other methods.

Yu, Daren; Huang, Xin; Wang, Huaning; Cui, Yanmei; Hu, Qinghua; Zhou, Rui

2010-02-01

439

Towards a predictive systems-level model of the human microbiome: progress, challenges, and opportunities.  

PubMed

The human microbiome represents a vastly complex ecosystem that is tightly linked to our development, physiology, and health. Our increased capacity to generate multiple channels of omic data from this system, brought about by recent advances in high throughput molecular technologies, calls for the development of systems-level methods and models that take into account not only the composition of genes and species in a microbiome but also the interactions between these components. Such models should aim to study the microbiome as a community of species whose metabolisms are tightly intertwined with each other and with that of the host, and should be developed with a view towards an integrated, comprehensive, and predictive modeling framework. Here, we review recent work specifically in metabolic modeling of the human microbiome, highlighting both novel methodologies and pressing challenges. We discuss various modeling approaches that lay the foundation for a full-scale predictive model, focusing on models of interactions between microbial species, metagenome-scale models of community-level metabolism, an