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In this study, a salt-tracer method applicability in Quaternary aquifer system groundwater was tested. The tracer experiment was performed in Vilnius University Kairėnai polygon for hydrogeological investigations in 2021. In Lithuania, experiments with tracers are not prevalent. Therefore, this work describes the practical use of the tracer for the analysis of the hydrogeological environment, a methodology that enables experiments with salt tracers. After the tracer test, the water flow rate was calculated at the time of the peak concentration of Ch, which reached 9.41 m/d. The effective porosity value was calculated manually (0.16) and using TRAC code (0.1389 and 0.1341; normalized for background values). The main results of tracer experiments show that sodium chloride solution is effective as a tracer in the Quaternary aquifer system of Lithuania for actual n calculation, where aquifer hydraulic conductivity values are similar to the studied area. Tracer peak analysis performed in this study confinns a possibility of estimating the heterogeneity of aquifer nef on site. [ABSTRACT FROM AUTHOR]

The hydraulic residence time (HRT) serves as a critical temporal scale for calculating the duration of pollutants within a water body. The spatial and temporal variations of HRT play a crucial role in developing location-specific water management strategies. In our study, we assessed the spatial and temporal distribution patterns of hydraulic residence time in Xinghai Lake, China – a representative case of large shallow lakes regulated by zoning – using a hydrodynamic-tracer model. The findings reveal that manipulating the outflow gates leads to a fluctuation range of 20 days in hydraulic residence time. Our analyses suggest that the operation of outflow gates significantly influences the reduction of hydraulic residence time. Compared with previous research, the spatial and temporal distribution patterns of hydraulic residence time examined in this study demonstrate the effectiveness of zonal regulation in improving water resource management. • Quantified the spatial and temporal distribution and fluctuation range of HRT. • Demonstrated the effectiveness of zonal regulation in water resource management. • Outflow is a key factor influencing hydraulic residence time in shallow lakes. [ABSTRACT FROM AUTHOR]

Incorporating organismal hydrogen (δ2H or δD) and oxygen (δ18O) stable isotope ratios into aquatic food web research can help elucidate relative reliance on shoreline inputs and/or feeding at different trophic levels; however, their interpretation is complicated by the fact that aquatic organisms derive hydrogen and oxygen from both their diet and the ambient water in which they reside. We examined spatial and seasonal patterns in δ2H and δ18O of field-collected water and small-bodied fishes. Samples were gathered from nearshore Lake Michigan, a dynamic region of a large, increasingly oligotrophic freshwater lake. We examined seasonal and spatial δ2H and δ18O values of surface and bottom water, and compared spatial δ2H and δ18O values of young-of-year yellow perch (Perca flavescens) and seasonal δ2H and δ18O values of round goby (Neogobius melanostomus). Nearshore δ2H and δ18O water values were more variable than previously-described offshore values. Variation in nearshore water δ2H and δ18O values was likely related to differential precipitation and/or discharges from tributaries, and there may be a surface dilution effect which led to lower δ18O values in nearshore surface waters than bottom waters. In our study, fish tissue δ2H and δ18O also varies more spatially than seasonally, and some findings suggest that fish tissue δ2H may reflect feeding at higher trophic levels. Though characteristics of the study system affect their interpretation, we suggest that δ2H and δ18O can be another tool to assess food web structure, with δ2H in particular having potential to resolve questions when δ13C or δ15N are inconclusive. [ABSTRACT FROM AUTHOR]

Previous studies of the nutrient budgets of lakes in Precambrian Shield regions have generally ignored the role of groundwater as a source or sink (influx or efflux) of nutrients. This paper and its companion (Part 2) address this science gap by probing the role of groundwater in the nutrient balance for a restricted bay of a Precambrian Shield lake that has undergone extensive shoreline development. In Part 1, we introduce a conceptual model of the relevant processes, including the role of groundwater. A cottage study site is described, concentrations of nutrients and septic tracers (artificial sweeteners), water levels and other data are reported. This includes data from samples of the septic wastewater plume in groundwater at the cottage, and samples from the bay. The artificial sweetener data indicate seepage of septic plumes to the bay, but significant attenuation of septic-derived nutrients in the subsurface. These data are used for numerical modeling in Part 2. [ABSTRACT FROM AUTHOR]

Copyright of Rudarsko-Geolosko-Naftni Zbornik is the property of Faculty of Mining, Geology & Petroleum Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Narragansett Bay is an urban estuary that historically has been impacted by long-term discharge of sanitary wastewater (WW) effluents. High-density water sampling was conducted in Narragansett Bay, RI, USA, in an effort to understand the distribution and behavior of sucralose, an artificial sweetener that has shown utility as a sanitary wastewater tracer. Water samples were collected at sixty-seven sites and analyzed for sucralose, whose performance was compared to other tracers present in wastewater effluents. Concentrations of sucralose were much higher than the other tracers measured, carbamazepine and caffeine, ranging from 18 to 3180 ng/L and corresponded well with salinity (r2 = 0.88), demonstrating conservative behavior throughout the Bay. Mapped interpolation data using an empirical bayesian kriging model clearly show the spatial trends of WW and how estuarine processes influence dilution and dispersion throughout the Bay. These findings provide further evidence of the efficacy of sucralose as a wastewater tracer in large urban estuaries where continuous high-volume discharge of WW occur. • Baysesian kriging plots of sucralose provided an estuary-wide snapshot of WW impacts. • Sucralose demonstrated conservative behavior when compared to salinity in an estuary. • Sucralose's concentration and persistence supports its utility as a WW tracer. • High-density sampling allowed precise examination of a WW tracer's performance. [ABSTRACT FROM AUTHOR]

Abstract The recent decline of the Arctic sea ice cover leads to an increasing number of vessels navigating through the Arctic shipping routes. Ballast water, essential for the vessel's safety during voyages and cargo transfers, however, is also considered one of the main vectors for transport and introduction of non-indigenous species. The aim of this paper is to investigate potential effects of the ballast water discharged in the main Arctic shipping routes on the local environment. For that a passive tracer was implemented in a fine resolution coupled ocean-sea ice model covering the entire Arctic and northern North Atlantic, to simulate the spread of the ballast water discharged based on release points along real ship positions from 2013. The model results showed that spring and summer were the seasons with the highest tendency for accumulation of ballast water tracer on the surface layers south of Novaya Zemlya and south of Spitsbergen, not only due to a higher number of vessels navigating in the area but also due to strong stratification. During winter and autumn, the tracer was mixed with and into deeper layers due to vertical convection. The simulated ballast water accumulation during spring and summer indicated that organisms, that survived the voyage in the ballast tanks, could establish a stable or growing population and eventually become invasive. Highlights • Ballast water tracer pathways and accumulation areas have strong seasonality. • High concentrations of ballast water tracer in deeper layers in winter and autumn. • During summer and spring tracer is kept in the surface layers due to stratification. • Tracer accumulated in the Barents Sea and west Spitsbergen during summer and autumn. • Ballast water accumulation may present risks of contamination to local environment. [ABSTRACT FROM AUTHOR]

Abstract Biomass burning (BB) is one of the largest sources of carbonaceous aerosols with adverse impacts on air quality, visibility, health and climate. BB emits a few specific aromatic acids (p -hydroxybenzoic, vanillic, syringic and dehydroabietic acids) which have been widely used as key indicators for source identification of BB-derived carbonaceous aerosols in various environmental matrices. In addition, measurement of p -hydroxybenzoic and vanillic acids in snow and ice cores have revealed the historical records of the fire emissions. Despite their uniqueness and importance as tracers, our current understanding of analytical methods, concentrations, diagnostic ratios and degradation processes are rather limited and scattered in literature. In this review paper, firstly we have summarized the most established methods and protocols for the measurement of these aromatic acids in aerosols and ice cores. Secondly, we have highlighted the geographical variability in the abundances of these acids, their diagnostic ratios and degradation processes in the environments. The review of the existing data indicates that the concentrations of aromatic acids in aerosols vary greatly with locations worldwide, typically more abundant in urban atmosphere where biomass fuels are commonly used for residential heating and/or cooking purposes. In contrast, their concentrations are lowest in the polar regions which are avoid of localized emissions and largely influenced by long-range transport. The diagnostic ratios among aromatic acids can be used as good indicators for the relative amounts and types of biomass (e.g. hardwood, softwood and herbaceous plants) as well as photochemical oxidation processes. Although studies suggest that the degradation processes of the aromatic acids may be controlled by light, pH and hygroscopicity, a more careful investigation, including closed chamber studies, is highly appreciated. Graphical abstract Schematic overview on the sources, transport, and deposition of biomass burning emissions. Image 1 Highlights • The analytical methods to quantify aromatic acids as BB tracer are summarized. • Abundances of the aromatic acids as BB tracer in different environments are discussed. • Degradation and hygroscopic properties have not been clarified up to now. • Perspectives involving measurement and field observation are recommended. Current research trends on aromatic acids as biomass burning tracers were comprehensively reviewed. [ABSTRACT FROM AUTHOR]

Reactor hydraulics are integral to water treatment processes such as disinfection and chemical contaminant oxidation. This work uses reactor networks—conceptual reactors arranged in parallel and series combinations—to simplify the accurate modeling of residence time in water treatment reactors. Reactor networks were selected for 14 clearwells, ozone contactors, clarifiers, and filters using tracer data sets from literature. For seven of 14 full‐scale reactors, two parallel tanks‐in‐series reactors best balanced accuracy and simplicity. Reactor networks accurately represented tracer data using between two and eight fitting parameters, while segregated flow analysis required 32–164 inputs (two per tracer data point). The modeling work revealed that tracer data sets may have overestimated baffle factors by >10% in 10 of the 14 full‐scale reactors, potentially as a result of inaccurate measurement of flow rate or volume. Applications of reactor networks include more accurate approaches to disinfection regulation and modeling the degradation of emerging contaminants. [ABSTRACT FROM AUTHOR]

Background Study objectives were to track the transfer of microbes on soft surfaces in health care environments and determine the efficiency of an Environmental Protection Agency (EPA)–registered soft surface sanitizer in the health care environment. Methods Soft surfaces at 3 health care facilities were sampled for heterotrophic plate count (HPC) bacteria, Staphylococcus spp, Streptococcus pyogenes , and Escherichia coli followed by a tracer study with a virus surrogate seeded onto volunteer hands and commonly touched surfaces. The occurrence of microbial contaminants was determined along with microbial reductions using the soft surface sanitizer. Soft surfaces were swabbed pre- and postintervention. Results Tracer viruses spread to 20%-64% and 13%-41% of surfaces in long-term health care facilities and physicians' offices, respectively. Only 1 pathogen, methicillin-resistant Staphylococcus aureus , was recovered. The waiting room chairs had the highest concentration of HPC bacteria before disinfection (145.4 ± 443.3 colony forming units [cfu]/cm 2 ), and the privacy curtains had the lowest (39.5 ± 84.2 cfu/cm 2 ). Reductions of up to 98.5% were achieved with the sanitizer in health care settings and up to 99.99% under controlled laboratory conditions. Conclusions Soft surfaces are involved in the spread of microbes throughout health care facilities. Routine application of an EPA-registered sanitizer for soft surfaces can help to reduce the microbial load and minimize exposure risks. [ABSTRACT FROM AUTHOR]

Understanding the near surface migration patterns and rates of efflux of CO 2 is important for developing effective monitoring and verification programs for the geological storage of CO 2 . Soil flux surveys are a well-established technique for characterising surface CO 2 emission sources from controlled release sites, CO 2 storage sites or natural CO 2 seeps. The performance of four interpolation methods; arithmetic mean (AM), two minimum variance unbiased estimators (MVUE), and a newly developed geostatistical cubic surface were evaluated using 21 soil flux surveys conducted over two controlled release experiments in 2012 and 2013, at the Ginninderra controlled release facility, Australia. Data was binned to approximate a regular sampling grid for improved performance of the whole-of-field AM and MVUE averaging techniques. The AM and MVUE methods were highly sensitive to deviations in the statistical distribution of the data, and performed inconsistently across the two experiments. These two methods proved ill-suited for application to CO 2 leak quantification due to their inflexible sampling and distribution requirements. The cubic technique provided the best net emission estimates across both experiments, and when applied at different bin sizes, estimating the true release rate to within 20% for the 2012 experiment and 45% below the release rate for the 2013 experiment. The cubic method is well-suited for CO 2 leak quantification because it is not limited by assumptions of the data's spatial or statistical distribution. Net H 2 O emissions of 29 kg/d were observed coincident with the high CO 2 flux zones in the field. The interpolation methods were applied with similar results on soil flux surveys taken from a natural seepage site in Qinghai, China. Gravity currents appear to describe the observed soil flux and soil gas behavior at Ginninderra, i.e. the observed lateral migration of CO 2 in the subsurface. Subsurface migration was also strongly influenced by the relative depth of the groundwater. Thus the low water table and greater vadose zone in the 2013 experiment is suspected to facilitate greater lateral CO 2 migration and explain the poor closure of the CO 2 balance. [ABSTRACT FROM AUTHOR]

Summary The molecular transducers of benefits from different exercise modalities remain incompletely defined. Here we report that 12 weeks of high-intensity aerobic interval (HIIT), resistance (RT), and combined exercise training enhanced insulin sensitivity and lean mass, but only HIIT and combined training improved aerobic capacity and skeletal muscle mitochondrial respiration. HIIT revealed a more robust increase in gene transcripts than other exercise modalities, particularly in older adults, although little overlap with corresponding individual protein abundance was noted. HIIT reversed many age-related differences in the proteome, particularly of mitochondrial proteins in concert with increased mitochondrial protein synthesis. Both RT and HIIT enhanced proteins involved in translational machinery irrespective of age. Only small changes of methylation of DNA promoter regions were observed. We provide evidence for predominant exercise regulation at the translational level, enhancing translational capacity and proteome abundance to explain phenotypic gains in muscle mitochondrial function and hypertrophy in all ages. [ABSTRACT FROM AUTHOR]

Drilling is an integral part of subsurface exploration. Because almost all drilling operations require the use of a drill fluid, contamination by infiltration of drill fluid into the recovered core material cannot be avoided. Because it is impossible to maintain sterile conditions during drilling the drill fluid will contain surface microbes and other contaminants. As contamination cannot be avoided, it has to be tracked to identify those parts of the drill core that were not infiltrated by the drill fluid. This is done by the addition of tracer compounds. A great variety of tracers is available, and the choice depends on many factors. This review will first explain the basic principles of drilling before presenting the most common tracers and discussing their strengths and weaknesses. The final part of this review presents a number of key questions that have to be addressed in order to find the right tracer for a particular drilling operation. [ABSTRACT FROM AUTHOR]

Sites throughout Boston Harbor were analyzed for caffeine to assess its utility as a tracer in identifying sources of sanitary wastewater. Caffeine ranged from 15 ng/L in the outer harbor to a high of 185 ng/L in the inner harbor. Inner harbor concentrations were a result of combined sewage overflow (CSO) events as well as illicit discharge of sanitary sewage into municipal storm drains. Comparing current results to data from 1998 to 1999 shows reductions in caffeine levels. Reductions are attributed to termination of effluent discharge to the harbor, declines in the number of CSOs and discharge volume along with efforts to eliminate illicit discharges. Spatial distributions of caffeine identified CSOs as major contemporary sources to the inner harbor. The findings further establish the utility of caffeine as a tracer for sanitary wastewater contamination in urban estuaries and demonstrate the efficacy of pollution reduction strategies undertaken in recent decades in Boston Harbor. [ABSTRACT FROM AUTHOR]

In this study, a new monitoring approach for detecting CO 2 leakage is proposed that utilizes hydrogen gas as a tracer for CO 2 geological storage. The gas leakage from a shallow formation is studied using 20–100-m deep boreholes at the Ito Natural Analog Site field testing facility in Fukuoka, Japan. Direct measurements of CO 2 concentrations may yield unreliable results, particularly in summer when high levels of CO 2 flux are produced from soil respiration. A gas mixture (CO 2 :H 2 /99:1) was injected through a well to the subsurface. The concentrations of gas emitted from the soil were measured in pipes where the gas was trapped; hydrogen was detected at 15 ppm immediately in less than 30 min after the mixed gas was released to the water-saturated zone. Repeated measurements were conducted in the area and elevated H 2 levels of 15–65 ppm were recorded for 2 weeks. CO 2 measurements in the pipes showed elevated levels at one monitoring point a day after the mixed gas was released. The field result was confirmed by laboratory experiments of the mixed gas, verifying that H 2 is detected earlier than CO 2 . The elapsed time between H 2 and CO 2 after the mixed gas released was observed in this study suggesting that H 2 has a potential as signal precursor for a future of CO 2 arrival. However, further experiment should be conducted to demonstrate the applicability of H 2 as a monitoring tool in CCS. [ABSTRACT FROM AUTHOR]

The number of products containing engineered nanomaterials (ENMs) has increased due to their high industrial relevance as well as their use in diverse consumer products. At the end of their life cycle ENMs might be released to the environment and therefore concerns arise regarding their environmental impact. In order to track their fate upon disposal, it is crucial to establish methods to trace ENMs in complex environmental samples and to differentiate them from naturally-occurring nanoparticles. The goal of this study was to distinctively trace ENMs by (non-invasive) detection methods. For this, fluorescent ENMs, namely quantum dots (QDs), were distinctively traced in complex aqueous matrices, and were still detectable after a period of two months using fluorescence spectroscopy. In particular, two water-dispersible QD-species, namely CdTe/CdS QDs with N -acetyl- l -cysteine as capping agent (NAC-QDs) and surfactant-stabilized CdSe/ZnS QDs (Brij ® 58-QDs), were synthesized to examine their environmental fate during disposal as well as their potential interaction with naturally-occurring substances present in landfill leachates. When QDs were spiked into a leachate from an old landfill site, alteration processes, such as sorption, aggregation, agglomeration, and interactions with dissolved organic carbon (DOC), led to modifications of the optical properties of QDs. The spectral signatures of NAC-QDs deteriorated depending on residence time and storage temperature, while Brij ® 58-QDs retained their photoluminescence fingerprints, indicating their high colloidal stability. The observed change in photoluminescence intensity was mainly caused by DOC-interaction and association with complexing agents, such as fulvic or humic acids, typically present in mature landfill leachates. For both QD-species, the results also indicated that pH of the leachate had no significant impact on their optical properties. As a result, the unique spectroscopic fingerprints of QDs, specifically surfactant-stabilized QDs, allowed distinctive tracing in complex aqueous waste matrices in order to study their long-term behavior and ultimate fate. [ABSTRACT FROM AUTHOR]

This study evaluated the occurrence of 36 PPCPs in urban river water samples collected from Beijing, Changzhou and Shenzhen. Twenty-eight compounds were detected. Compounds found with highest median concentrations included: sulfadimethoxine (164 ng/L), sulpiride (77.3 ng/L), atenolol (52.9 ng/L), and indomethacin (50.9 ng/L). Antibiotic was the predominant class detected and contributed about half of the overall PPCPs contamination level. Effluents from wastewater treatment plants (WWTPs) were demonstrated to be the predominant pathways through which PPCPs entering into aquatic environment in all investigated areas. The ratio of persistent PPCPs like sulpiride and carbamazepine was identified to be feasible in tracing their contamination sources in rivers. Concentrations of most detected PPCPs showed significant positive correlations with total nitrogen and total phosphorus. Two groups of representative PPCPs were selected as the chemical indicators for predicting the overall PPCPs contamination, based on the significant correlations between PPCPs. [ABSTRACT FROM AUTHOR]

In 2015, CO 2 injection will start at the Quest Carbon Capture and Storage (CCS) Project in Alberta, Canada. The Quest Carbon Capture and Storage (CCS) project is a joint venture between Shell Canada Energy, Chevron Canada Limited, and Marathon Oil Canada Corporation, and is operated by Shell. The CO 2 is captured from the Scotford oil sands bitumen upgrader, located northeast of Edmonton. Up to 1 Mt of CO 2 per year will be injected into the Basal Cambrian Sandstone (BCS), a saline aquifer located at a depth of about 2 km below ground surface, over a potential time period of 25 years. In order to demonstrate containment and conformance of the injected CO 2 , implementation of a Measurement, Monitoring and Verification (MMV) plan is essential. A number of technologies can be used within a MMV plan, such as geophysical or geochemical techniques. The latter may include chemical and/or isotopic fingerprinting of specific fluid end-members, such as the BCS brine. The aim of this paper is to provide an overview of the work that has been undertaken to assess the use of natural tracers for MMV purposes at the QUEST CCS project. The two key objectives are to a) review chemical and isotopic compositions of the BCS brine compared to overlying aquifer waters, and b) to assess the suitability of the natural abundance C and O isotopic compositions of injected CO 2 as a tracer. [ABSTRACT FROM AUTHOR]

This study examines the circulation, flushing time and hydrodynamic connectivity in Halifax Harbour based on three-dimensional currents produced by a multi-nested coastal ocean circulation modelling system. The time-mean currents produced by the modelling system feature two-layer estuarine circulation with a seaward flow in the upper layer and a landward flow in the lower layer in the Harbour. The hydrodynamics in the Harbour are also affected significantly by tides and wind forcing. Based on numerical passive tracer experiments, the estimated e-folding flushing time is about 40 and 90 days in the upper and the entire Bedford Basin, respectively. By comparison, the flushing time is about 2-5 days over the Inner and Outer Harbour, and only about 1 day in the Narrows. Analysis of passive particle trajectories carried by the model currents demonstrates that movements of particles in the Harbour are strongly affected by tidal and storm-induced currents. Hydrodynamic connectivity in the study region is also quantified in terms of a connectivity matrix calculated from particle trajectories. [ABSTRACT FROM AUTHOR]

Abstract: A description of a new technology for automatic sorting of plastics, based on X-ray fluorescence detection of tracers, added in such materials is presented. This study describes the criteria for the selection of tracers, and concluded that the most adapted for XRF are some rare earth oxides. The plastics chosen for tracing and identification are the ones contained in ELV and WEEE from which discrimination is difficult for the existing sorting techniques due to their black colour. [Copyright &y& Elsevier]

The article discusses the study on the use of biotinylated dextran amine in investigating the corticospinal tract (CST). The study used goats as models of ischemic spinal cord injury, through digital subtraction angiography and embolization. The study subjects with spinal cord injury were injected with biotinylated dextran amine. Results show the efficiency of biotinylated dextran amine as anterograde tracer for CST.

Abstract: The CO2SINK project in Ketzin represents a field laboratory for the storage of CO2 in a 650-m deep saline aquifer. The project is accompanied by a microbiological monitoring programme to characterise the composition and activity of the autochthonous microbial community in rock and brine samples and their changes in response to CO2 storage. A prerequisite of these studies is the acquisition of samples free of contamination from microorganisms and organic and inorganic components. Drilling mud and technical fluids are the main sources of contamination. This study describes the application of the fluorescent dye tracers fluorescein and rhodamine B as contamination controls for rock core and brine samples. Fluorescein was added to drilling mud that was used during the coring phase of the Ketzin wells Ktzi 200, 201 and 202. In addition, total organic carbon (TOC) concentrations, reflecting the carboxymethyl cellulose (CMC) component of the drilling mud, were determined to verify the tracer results. The fluorescence and TOC analyses revealed that drilling mud filtrate penetrated the outer 20mm of mildly permeable sandstone cores. Rhodamine B was added to brines that were used to displace the drilling mud and to flush the wells after completion. The tracer monitoring during the discharge of drilling mud and displacement brines from the wells during hydraulic tests and nitrogen lifts enabled the quantification of reservoir fluid quality. After the production of 140–190m3 (16–21 borehole volumes) of fluid, the drilling mud concentration was reduced to about 0.05%. The use of fluorescein emerged as a field-capable, sensitive and reliable method during the sampling of rock core and formation brine samples. [ABSTRACT FROM AUTHOR]

Based on the Environmental Fluid Dynamics Code ( EFDC), a three-dimensional baroclinic model for lower reaches of the Yangtze River, Yangtze River Estuary, Hangzhou Bay and the adjacent sea areas was established with the sigma-coordinate in the vertical direction and the orthogonal curvilinear coordinates in the horizontal direction. The fine silt particle tracers were injected during different tides with the calibrated three-dimensional numerical model in the Yangtze River Estuary to simulate the migration tracks of the tracers in the following three days, and thereby study the migration behavior of the fine silt particles of dredged sediment after dumping at different locations in the navigation channel in the Yangtze River Estuary. The study shows that the particle paths of the tracer particles basically migrate to the open sea along the middle axis of river course in the form of reciprocating oscillation, the migration and diffusion directions of tracer particles are basically parallel to the navigation channel in guide levee, similar to long belt distribution, and the tracer particles migrate to the southeast out of the guide levee. The particle which is on the southern and northern sides enter groin and cross the navigation channel in the process of movement, and is easy to deposit in the navigation channel. The migration tracks of the particles released at different layers are basically similar at the same release station, but specifically different, varying at different cross sections. The result can be used for the choice and evaluation of dredging schemes in the Yangtze River Deepwater Navigation Channel. [ABSTRACT FROM AUTHOR]

Abstract: The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, chemically analyzed, and compared. The samples were sieved to isolate the <63 μ m fraction and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). On the basis of substantial and consistent compositional differences among the source types, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected for use in the estimation of sediment sources. To further account for differences in particle-size composition between the sources and the reservoir bottom sediment, constituent ratio and clay-normalization techniques were used. Computed ratios included TOC to TN, TOC to TP, and TN to TP. Constituent concentrations (TN, TP, TOC) and activities (137Cs) were normalized by dividing by the percentage of clay. Thus, the sediment-source estimations involved the use of seven sediment-source indicators. Within the Perry Lake Basin, the consensus of the seven indicators was that both channel-bank and surface-soil sources were important in the Atchison County Lake and Banner Creek Reservoir subbasins, whereas channel-bank sources were dominant in the Mission Lake subbasin. On the sole basis of 137Cs activity, surface-soil sources contributed the most fine-grained sediment to Atchison County Lake, and channel-bank sources contributed the most fine-grained sediment to Banner Creek Reservoir and Mission Lake. Both the seven-indicator consensus and 137Cs indicated that channel-bank sources were dominant for Perry Lake and that channel-bank sources increased in importance with distance downstream in the basin. [Copyright &y& Elsevier]

The article focuses on the use of independent tracers to increase throughflow through a mining pit, specifically Herman Pit, an abandoned mercury (Hg) mine pit adjacent to Clear Lake, in California. Topics include the kind of tracers being used such as Rhodamine-WT, sulfur hexafluoride, and a mixture of sulfur hexafluoride and neon-22, the geochemical inferences, and watershed during storms.

Three independent tracer experiments were conducted to quantify the through‐flow of water from Herman Pit, an abandoned mercury (Hg) mine pit adjacent to Clear Lake, California, USA. The tracers used were Rhodamine‐WT, sulfur hexafluoride, and a mixture of sulfur hexafluoride and neon‐22. The tracers were injected into Herman Pit, a generally well‐mixed water body of ∼81 000 m2, and the concentrations were monitored in the mine pit, observation wells, and the lake for 2–3 months following each injection. The results for all three experiments showed that the tracer arrived at certain observation wells within days of injection. Comparing all the well data showed a highly heterogeneous response, with a small number of wells showing this near‐instantaneous response and others taking months before the tracer was detectable. Tracer was also found in the lake on four occasions over a one‐month period, too few to infer any pattern but sufficient to confirm the connection of the two water bodies. Using a simple mass balance model it was possible to determine the effective loss rate through advection for each of the tracers and with this to estimate the through‐flow rate. The through‐flow rate for all three experiments was ∼630 L/s, at least 1–2 orders of magnitude larger than previous estimates, all of which had been based on geochemical inferences or other indirect measures of the pit through‐flow. [ABSTRACT FROM AUTHOR]

Tracer studies are combined with a three‐dimensional (3‐D) numerical modeling study to provide a robust description of hydrodynamic and particle transport in Clear Lake, a multi‐basin, polymictic lake in northern California, USA. The focus is on the mechanisms of transport of contaminants away from the vicinity of the Sulphur Bank Mercury Mine and out of the Oaks Arm to the rest of the lake and the hydraulic connection existing among the sub‐basins of the lake. Under stratified conditions, the rate of spreading of the tracer was found to be large. In less than a week the tracer spread from the eastern end of the Oaks Arm to the other basins. Under non‐stratified conditions, the tracer spread more slowly and had a concentration that gradually diminished with distance from the injection location. The numerical results showed that the mechanisms accounting for these observed patterns occur in pulses, with maximum rates coinciding with the stratified periods. Stratification acts first to enhance the currents by inhibiting vertical momentum mixing and decoupling the surface currents from bottom friction. The diversity of the flow structures that results from the interaction of the wind and the density fields in the lake is responsible for the high dispersion rates. Contaminants originating in the Oaks Arm are shown to be transported into the Lower Arm following the surface currents and into the Upper Arm mainly through the bottom currents. It was also shown that, under stratified conditions, both the baroclinic (density driven) gradients and the wind forcing act jointly to exacerbate the interbasin exchange. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examines the mechanisms of contaminant in the Clear Lake, California. Topics include the use of three dimensional (3-D) numerical modeling study to provide a robust description of hydrodynamic and particle transport in the said lake, the mechanisms of transport of contaminants away from the vicinity of the Sulphur Bank Mercury Mine, and the hydraulic connection existing among the sub-basins of the lake.

Copyright of Diabetes & Metabolism is the property of Masson Editeur and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: A numerical modeling study was carried out to compute average residence time in a tide-dominated East Scott Creek Estuary, South Carolina. The East Scott Creek estuary is a long system of meandering tidal creeks and salt marsh between Edisto Island and the Edisto Beach barrier island, in South Carolina. A coupled hydrodynamic and solute transport model was developed. The flow and solute transport models were based on depth-integrated conservation equations. The equations were discretized by using the total variation diminishing (TVD) finite-volume method. The numerical model predictions were verified against a set of field-measured hydrodynamic data, with the model-predicted water elevations and velocities in good agreement with the field measurements. A remnant function method has been used to quantify the transport mechanism for a dissolved substance in a spatially varying situation with multiple sources, using a high-resolution mass-preserving hydrodynamic and mass-transport model. The spatially varying average residence times for a tide-dominated environment were investigated through a series of numerical experiments using a passive dissolved and conservative tracer as a surrogate. The result indicated that the average residence time varies with the tidal amplitude. The average residence time for the whole estuary for spring-tide condition was found to be about 22h. The corresponding average residence time for a tracer placed at the head of the estuary was about 170h. These findings provide useful information for understanding the transport process in the East Scott Creek Estuary that can be used to assess the impact of coastal development in and around the estuary. [Copyright &y& Elsevier]

Abstract: The effect of immobile water content on contaminant advection and dispersion in unsaturated porous media has been studied using a formulation which assumes that even in the immobile liquid zone, there occurs minor liquid flow. An approach is proposed for computing this liquid velocity. One dimensional numerical simulation is carried out to study the effect of immobile water content on the time of appearance of contaminant at the bottom of an unsaturated column. The numerical model developed is verified using analytical solutions for simple advective-dispersive cases. From the simulations, it was observed that increase in the immobile water content leads to quicker appearance of contaminant. [Copyright &y& Elsevier]

The results from a water supply network model simulated on a computer should ideally match the values recorded in the field. Such a validation is known as calibration. Good calibration of a supply network can lead to higher standards of service for public health and safety. This study uses genetic algorithms (GAs), a relatively new approach to optimization, to refine the demand values associated with nodes in a network. This approach is used to obtain a more precise hydraulic calibration of an existing network. Suitable tracers, such as fluoride supplied to the network of pipes, may help to make the calibration procedure significantly easier. To accomplish this purpose, a GA-based computer code was generated. The methodology introduced here uses fluoride concentrations from an existing network in the U.S. as the basis for the calculation of nodal demands. In order to check the validity of the model further, a fictitious network is also analyzed. [ABSTRACT FROM AUTHOR]

Mixing is one of the most important operations in high-rate digesters because it maintains uniformity within the digester and prevents scum accumulation. The mixing of anaerobic digester contents significantly influences the efficiency of digestion bioprocesses. Hydraulic dead zones in the reactor reduce the effective hydraulic retention time and, thus, have detrimental effects on the reaction kinetics. In this study, the efficiency of mixing by gas recirculation was examined in a digester of the Haifa Wastewater Treatment Plant (HWWTP). There are various methods and models to evaluate the mixing efficiency of anaerobic digesters [1]. The method used in this study was based upon injection of a fluoride tracer into the reactor at a certain feeding point, followed by a three-dimensional mapping of the fluoride distribution in the reactor as a function of time. Analyzing the results of uniform tracer distribution, it was concluded that there are no real 'dead zones' in the reactor's volume. However, when comparing with literature results of tracer distribution in other digesters, it was concluded that the mixing efficiency is very low and hardly sufficient for having an effective process. Some practical improvements, necessary to achieve higher mixing efficiency, were recommended. [ABSTRACT FROM AUTHOR]

Abstract: Laser-induced fluorescence (LIF) imaging of mixing processes frequently employs 3-pentanone or toluene as a fluorescence tracer. The analysis of measured LIF signals typically requires corrections for the influence of temperature, pressure, and gas composition on the signal strength in cases where these variables are not constant for the process under study, e.g., in internal combustion engines. However, fluorescence quantum yield data at simultaneous high temperature and high pressure are not well characterized. Therefore, the ability of two fluorescence models to predict the signal strength for 3-pentanone and toluene, respectively, under those conditions has been evaluated through comparison to LIF measurements using 248nm excitation in a motored optical engine. The temperature-pressure manifold that was covered ranges from 0.45bar, 328K to 8bar, 600K. A semi-empirical, photophysical model for 3-pentanone combines the effects of temperature, pressure, and excitation wavelength on fluorescence quantum yield. The qualitative influences of p and T reflect an increasing non-radiative decay rate with the excited electronic state’s vibrational energy level and the tendencies of collisions to remove the excess vibrational energy. The model for toluene seeks to quantify the fluorescence quantum yield via the effects of intra-molecular deactivation as well as collisional deactivation dominated by molecular oxygen. Model-predicted LIF signal strengths for 3-pentanone did not capture the signal modulations measured under the engine conditions, but agreement was much better using predictions based directly on the measured temperature and pressure dependencies in cell experiments. The toluene LIF model is able to reproduce the observed LIF signal strength in the engine with good accuracy. It is shown that quantitative analysis of toluene LIF requires knowledge of temperature and oxygen partial pressure. Therefore, the frequently applied assumption that the toluene-LIF signal is proportional to the equivalence ratio is not correct for the range of pressures and temperatures typical for the compression stroke in internal combustion engines. [Copyright &y& Elsevier]

Abstract: Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem. [Copyright &y& Elsevier]

This paper deals with the implementation of a tracer in a development environment for multiagent systems, where debugging is a major problem. A multiagent system consists of concurrent processes, so that debugging such a system involves difficulties related to the debugging of concurrent processes. We describe a tracer for debugging a multiagent system. A tracer is a program that traces program execution and obtains information on its status. Debugging by a tracer causes a problem called the probe effect, in which the debugger's interference with the program causes changes in its behavior. The probe effect is a major problem in debugging parallel processes. The tracer that we propose can limit the probe effect arising from delay in execution of an agent caused by the tracer. This tracer adjusts the execution speed of non-debugged agents in accordance with the execution delay of the debugged agent in order to limit the probe effect. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(12): 103–111, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1220 [ABSTRACT FROM AUTHOR]

As part of a wider study to optimise the adjustment of axial fan orchard sprayers to suit differing modern crop structures, three field experiments compared the effects of reductions in air volumetric flow rate (from 11.3 to 7.5 to 4.1 m3 s−1) on spray deposits and losses to young dwarf, dwarf and semi-dwarf apple trees. Reducing the air volumetric flow (achieved by reducing the speed of rotation of the fan without changing the air ducting or orifice size) from the high to the medium rate did not significantly affect mean deposits on the target trees but the lowest air flow rate increased mean deposits on leaves, flowers and fruits significantly in two experiments. In the other experiment, done in the early season in higher wind speed conditions, mean deposits were decreased by the lowest air flow rate treatment which made the spray plume vulnerable to cross-winds. Decreasing the air flow rate generally increased mean deposits in tree zones close to the sprayer and decreased those in zones furthest from the sprayer. The leaf-to-leaf distributions of deposits in the centre of the trees were not affected significantly by the reductions in air flow rate. Decreasing the air flow rate substantially increased the percentage spray cover on downward-facing water sensitive papers fixed horizontally in the centre of the trees but decreased cover on upward facing papers. The medium air flow rate gave at best only small (<50%) reductions in spray drift but the lowest air flow rate treatment significantly reduced drift by 55–93%. Deposits on ground sampling lines increased correspondingly. Drift amounts were greatest and the reductions in drift due to the reduced air flow rates were least in stronger winds conditions early in the season when the canopy was least dense.Taken together, these results indicate that large reductions in air volumetric flow rate can substantially reduce spray drift from axial fan sprayers without adversely affecting the variability of deposits on either leaf surface though the relative mean amounts on the upper versus the lower leaf surface can change substantially. The reductions make the spray plume more vulnerable to cross-winds which can reduce spray penetration. The extent that reductions can be made depends on wind conditions and tree density. However, the provision for air flow adjustment on many commercial sprayers is generally inadequate to maintain an optimal spray distribution pattern across the broad range of orchard structures that exist on many commercial farms in the UK. Other practical difficulties of greatly reducing the air flow rate are discussed. [Copyright &y& Elsevier]

The potential for insect resistance to the spinosyns, a novel class of insecticide chemistry, was examined using a laboratory strain of the tobacco budworm, Heliothis virescens (F.), originally collected from tobacco at sites in North Carolina. Technical grade spinosad (spinosyns A and D), was topically applied to third instars. Initially 533 third instars were used but one to two thousand larvae were treated per generation thereafter. Initially mortality ranged from 75% to 85% with doses of 0.044–0.088 μg per larva, until the fifth generation (G5) when mortality decreased. The selection dose was subsequently increased every generation from G5 to G11 in an attempt to restore mortality to >70%. After six generations of selection, the LD50 of the selected budworms was 1.68-times that of the parental generation (G1) as estimated 15 d after treatment. By G14, the topical LD50 of the selected insects was 1068-fold greater than the parental generation. Four additional populations of the budworm from the southeastern US demonstrated similar LD50s to spinosad as our parental strain, suggesting that the parental budworms from North Carolina were representative of field populations elsewhere. The resistance ratio determined with spinosad (formulated as Tracer®) in heliothine diet was 314-fold at 15 d after the start of exposure. Injection of spinosad into the larval hemocoel resulted in a >163-fold resistance ratio 15 d after injection, indicating that resistance could not be explained simply by altered penetration alone. Mortality was delayed in the resistant relative to the parental generation regardless of whether third instars were topically treated or exposed to treated diet. Spinosad resistance was also expressed in G14 adults, indicating that an adult vial test would be feasible for monitoring resistance. A feeding disruption assay was developed to monitor larval resistance in the field. [Copyright &y& Elsevier]

At present methods for measuring soil deposits from pesticide applications are somewhat limited. As an alternative to using pesticide residue analysis, a simple tracer technique has been developed using the fluorescent dye Tinopal CBS-X to measure deposits directly on the soil. Because there are soil tracer interactions with Tinopal CBS-X, the technique allows for variations in organic matter content by making use of a sorption isotherm as a calibration line. Laboratory measurements showed that tracer deposits on soil were comparable to those on artificial surfaces placed on the soil at the same location. Measurements from laboratory spray simulations and field experiments showed that there was high level of variability in the quantity of tracer recovered on soil. This was due to deposit variability below the crop, across the swath, and between sample locations rather than from the sampling method indicating that shading by the crop canopy has a significant effect on deposition. Because soil samples can be taken without bias, it was concluded that a more accurate indication of the amount reaching the soil could be obtained from soil surface sampling than from the use of artificial surfaces mounted on tables. [Copyright &y& Elsevier]

Recently, emerging pollutants, such as anthelmintics have attracted an increasing attention worldwide due to their extensive use and notable stability. However, the information on anthelmintics in the environment of southwest China is scarce. Thus, the occurrence, ecological risk and exposure evaluation of nineteen anthelmintics in Tuojiang River, which is one of the largest tributaries of Yangtze River, and drinking water source of Sichuan, southwest China, were investigated. The result showed that the detection frequency of anthelmintics was relatively high in Tuojiang River, ranging from 65% to 100% in river water. Among the seven kinds of anthelmintics, benzimidazoles are the primary anthelmintics, with concentrations up to 61.12 ng/L and 596.06 ng/g in water and sediment of the Tuojiang river, respectively. The total concentration of 19 anthelmintics in sediment samples from non-agricultural area was higher than that in agricultural area(p = 0.000 < 0.05). This could be attributed to anthropogenic activities, which lead to greater discharge and accumulation of anthelmintics in residential area along the river. It's worth to mention that the highest total concentrations of anthelmintics (109.28 ng/L) was found at the junction of rivers in R31 site. The results could be ascribed to the complexity of junction of Tuojiang River and Yangtze River, which could influence the distribution of pollutant. Besides, the ecological risk assessment showed that the macrocyclic lactones rather than benzimidazoles had relatively high toxicity to non-target organisms in aquatic environment (p = 0.000 < 0.05), with the highest RQ Ecotox value of 101 for Daphnia magna , while benzimidazoles had relatively high concentrations. The exposure risk could be ignored for both children and adults because the daily intake of anthelmintics via water ingestion were below 10 ng/kg/d. In addition, strong correlations were found between sucralose and most of the selected anthelmintics in Tuojiang River, indicating that sucralose might be a good tracer to evaluated the source of anthelmintics in surface water. This study provides the levels, risks and even some tracer information of pollutants for better understanding of anthelmintics in southwest China. • Benzimidazoles were the primary pollutant for anthelmintics in water and sediments from Tuojiang River. • Macrocyclic lactones posed the mainly ecological risk with the highest RQ Ecotox value for Daphnia magna. • There was no obvious exposure risk for both children and adults via water ingestion. • Sucralose could be a suitable tracer for anthelmintics in surface water. [ABSTRACT FROM AUTHOR]

Summary Current understanding of in vivo human brown adipose tissue (BAT) physiology is limited by a reliance on positron emission tomography (PET)/computed tomography (CT) scanning, which has measured exogenous glucose and fatty acid uptake but not quantified endogenous substrate utilization by BAT. Six lean, healthy men underwent 18 fluorodeoxyglucose-PET/CT scanning to localize BAT so microdialysis catheters could be inserted in supraclavicular BAT under CT guidance and in abdominal subcutaneous white adipose tissue (WAT). Arterial and dialysate samples were collected during warm (∼25°C) and cold exposure (∼17°C), and blood flow was measured by 133 xenon washout. During warm conditions, there was increased glucose uptake and lactate release and decreased glycerol release by BAT compared with WAT. Cold exposure increased blood flow, glycerol release, and glucose and glutamate uptake only by BAT. This novel use of microdialysis reveals that human BAT is metabolically active during warm conditions. BAT activation substantially increases local lipolysis but also utilization of other substrates such as glutamate. [ABSTRACT FROM AUTHOR]

Summary: Background & aims: Accurate assessment of energy expenditure (EE) is important in guiding nutritional therapy but current methods are unsatisfactory. This study compared the oral 13C-bicarbonate tracer (BT) technique using the IRIS® system (Wagner, Germany) against indirect calorimetry (IC, ventilated-hood) to measure CO2 output (VCO2) and thus estimate EE. Methods: Ten overnight-fasted healthy male volunteers were randomised to studies at rest or mild exercise in a crossover manner. During each study BT-IRIS® and IC were used simultaneously to measure VCO2 and thus EE. Participants ingested a drink labelled with 50 mg 13C-bicarbonate and breath samples were collected every 5 min for 180 min and analysed using IRIS®. Bland–Altman plots were used to assess agreement between the two techniques in measurements of VCO2 (L/day) and estimates of EE (kJ/day). Results: Mean ± SE age and BMI of participants were 21.1 ± 1.1 yrs and 23.6 ± 0.6 kg/m2. Both at rest and exercise, there was small bias but overall poor agreement between the two techniques as evident by the wide 95% limits of agreement in measurements of VCO2 and EE: rest VCO2 (bias 1.4, SD 93, 95% limits of agreement −180 to 183), rest EE (−8.3, 1830, −3595 to 3578), exercise VCO2 (49.3, 66.1, −80.4 to 178.9) and exercise EE (1083, 1944, −2727 to 4893). Furthermore, there was also evidence of systematic error in these measurements. Conclusion: Prior to clinical application, further optimisation of the BT-IRIS® system should be undertaken, given the poor agreement with IC in measuring VCO2 and estimating EE. [ABSTRACT FROM AUTHOR]

An abstract of the article "Effects of a 13C ration stable meal for the 13C ration in breath CO2," by Tsuyoshi Masuda and Youichi Aibe is presented.

FD&C Blue #1 and Rhodamine WT have been used in soils to trace preferential flow paths while bromide has been used, to study flow paths of water or nonretarded chemicals. This study quantified the interactions of KBr, FD&C Blue #1, and Rhodamine WT on dye adsorption in Forman loam (fine-loamy, mixed Udic Argiboroll) soil. The experimentinvolved characterization of adsorption isotherms and breakthrough curves for various mixtures of tracers at different concentrations. Batch equilibration studies showed that the adsorption of FD&C Blue #1 and Rhodamine WT on Forman loam was not influenced by the presence ofeach other. The adsorption of FD&C Blue #1 and Rhodamine WT, however, increased with an increase in the concentration of KBr. The slope of linear adsorption isotherm (Kd increased from 5.0 to 15.0 cm3 g-1 for FD&C Blue #1 and from 4.2 to 5.0cm3 g-1 for Rhodamine WT on addition of 1000 mg L-1 of KBr. In a flow-through experiment, FD&C Blue #1 movement was twice as slow in presence of KBr than in absence of KBr. The K, values from the flow-through experiment were lower than those from the batch equilibration experiments. We conclude that the retardation coefficients estimated from the batch equilibration studies arenot realistic for application to leaching experiments, and the presence of tracer interaction can potentially complicate the interpretation of dye flow patterns observed with the use of multiple tracer technique. [ABSTRACT FROM AUTHOR]

Water-supply managers need adequate warning to protect water supplies if a contaminant is spilled in an upgradient tributary. The city ofLincoln draws water from alluvium associated with the Platte River near Ashland, eastern Nebraska. Using constant-rate injection methods and a conservative tracer, travel time and degree of mixing of contaminants in the Elkhorn and Platte Rivers were evaluated in 1995 and 1996. The results indicate that, for flows of 584 to 162 m3sin the Platte River at Ashland with 13 to 28% of its flow contributed by the Elkhorn River, 8.2 to 13.2 h are required for the leading edge of a chemical plume to travel from the Elkhorn River at Waterloo to the Platte River at Ashland. The peak concentration of a chemical spilled as a slug in the Elkhorn River near Waterloo would pass the well field after 11.3 to 16.1 h. Existing empirical equations for calculation of travel time were shown to apply to reaches of streams studied, but underestimated the leading edge up to 14% and overestimated the plateau concentration up to 11% at Site 5. However, time of travelmay be influenced by the relative contribution of a tributary. The plateau concentration of the chemical in the Platte River at Ashland was 45 to 60% of its concentration in the Elkhorn River. The degree ofmixing of the tracer in the Platte River at Ashland increased from 53 to 65% as the relative contribution of the Elkhorn River increased. [ABSTRACT FROM AUTHOR]