bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrological response of weathered clay‐shale slopes: water infiltration monitoring with time‐lapse electrical resistivity tomography
Authors: Travelletti J. , Sailhac P. , Malet J.‐P. , Grandjean G. , Ponton J. 
Published: February 2011

AbstractThis work presents an attempt to monitor water infiltration and subsurface flow within a clay‐shale landslide using time‐lapse electrical resistivity tomography (ERT). A rainfall experiment was carried out on a plot of 100 m2at the Laval landslide in the Draix experimental catchments (ORE Draix, South French Alps) in order to characterize the spatial and temporal development of water circulation in the soil and to identify when steady‐state flow conditions are reached. The experiment was conducted during 67 h with initial unsaturated conditions in the slope. The apparent electrical resistivity values were inverted with a time‐lapse approach using several cross models. The results indicate a significant decrease in resistivity (−18%) compared to the initial state in the rain plot. Downslope progression of negative resistivity anomalies is imaged suggesting that vertical and subsurface lateral flows have developed. About 21 h after the start of the rain experiment, a constant level of resistivity values is observed indicating that the hydrological system reached steady‐state flow conditions. This observation is consistent with ground water level observations and chemical tracer analysis. Computed differences in time of steady‐state conditions highlight possible preferential flows near the landslide toe. A hydrological concept of functioning of the slope is proposed, and apparent saturated hydraulic conductivity (Ksof 1·7 × 10−4m × s−1) is computed from the steady‐state times. This study demonstrates the potentiality of ERT monitoring to monitor water infiltration in clay‐shale slopes and the high water transfer capacity of reworked clay‐shale material. Copyright © 2011 John Wiley & Sons, Ltd.
Hydrological extremes in the Poyang Lake basin, China: changing properties, causes and impacts
Authors: Zhang Qiang , Sun Peng , Chen Xiaohong , Jiang Tao 
Published: February 2011

AbstractProbability behaviours and trends of hydrological extremes, the 7‐day high flow (HF7) in this study, of the Poyang Lake basin are thoroughly investigated using 11 probability distribution functions and Mann‐Kendall trend test method. Parameters and goodness‐of‐fit of the probability functions are estimated using the L‐moment technique and Kolmogorov‐Smirnov statistic D (K‐S D). The hydrological data are extracted from six major hydrological stations located in the five main tributaries of the Poyang Lake basin. The results indicate that: (1) the Wakeby distribution is the good choice for description of the statistical behaviours of HF7 in the study region; (2) changing properties of HF7 are varying from on station to another, implying different fluvial geomorphological features, climate changes, and human activities within different tributaries. Generally, the HF7 events are increasing after the construction of water reservoirs except the Wan'an water reservoir. The analysis results demonstrate considerable influences of water reservoirs on high flow changes. Relatively low design standards of the water reservoirs greatly limit the functions of the water reservoirs in terms of flood control. Besides, most water reservoirs were built in the tributaries of the Poyang Lake basin, exerting limited influences on the streamflow extremes; (3) higher frequency of hydrological extremes may cause higher probability of floods, posing increasingly serious challenges for flood control. In this sense, more efforts should be paid to enhance human mitigation to natural hazards such as floods in the Poyang Lake basin. Copyright © 2011 John Wiley & Sons, Ltd.
Internal catchment process simulation in a snow‐dominated basin: performance evaluation with spatiotemporally variable runoff generation and groundwater dynamics
Authors: Kuraś Piotr K. , Alila Younes , Weiler Markus , Spittlehouse Dave , Winkler Rita 
Published: February 2011

AbstractHydrologic models have increasingly been used in forest hydrology to overcome the limitations of paired watershed experiments, where vegetative recovery and natural variability obscure the inferences and conclusions that can be drawn from such studies. Models are also plagued by uncertainty, however, and parameter equifinality is a common concern. Physically‐based, spatially‐distributed hydrologic models must therefore be tested with high‐quality experimental data describing a multitude of concurrent internal catchment processes under a range of hydrologic regimes. This study takes a novel approach by not only examining the ability of a pre‐calibrated model to realistically simulate watershed outlet flows over a four year period, but a multitude of spatially‐extensive, internal catchment process observations not previously evaluated, including: continuous groundwater dynamics, instantaneous stream and road network flows, and accumulation and melt period spatial snow distributions. Many hydrologic model evaluations are only on the comparison of predicted and observed discharge at a catchment outlet and remain in the ‘infant stage’ in terms of model testing. This study, on the other hand, tests the internal spatial predictions of a distributed model with a range of field observations over a wide range of hydroclimatic conditions. Nash‐Sutcliffe model efficiency was improved over prior evaluations due to continuing efforts in improving the quality of meteorological data collection. Road and stream network flows were generally well simulated for a range of hydrologic conditions, and snowpack spatial distributions were well simulated for one of two years examined. The spatial variability of groundwater dynamics was effectively simulated, except at locations where strong stream–groundwater interactions exist. Model simulations overall were quite successful in realistically simulating the spatiotemporal variability of internal catchment processes in the watershed, but the premature onset of simulated snowmelt for one of the simulation years has prompted further work in model development. Copyright © 2011 John Wiley & Sons, Ltd.
Drainage water temperature as a basis for verifying drainage runoff composition on slopes
Authors: Zajíček Antonín , Kvítek Tomáš , Kaplická Markéta , Doležal František , Kulhavý Zbyněk , Bystřický Václav , Žlábek Pavel 
Published: February 2011

AbstractTile drainage water temperatures and discharge rates were measured in five highland watersheds of which most are underlain by acid crystalline rock. One of them, Dehtáře in the Bohemo‐Moravian highland (Czech Republic), was studied in greater detail. The aim was to evaluate water temperature monitoring as a means of determining the source and pathway of drainage runoff during high‐flow events. Rapid increase in drainage discharge was accompanied by rapid change in water temperature. In winter, the rising limb of the hydrograph was accompanied by a decrease in temperature, and the falling limb was associated with a corresponding temperature increase. In summer, the trends were reversed. These data suggest that the water temperature changes are caused by the fastest component of drainage runoff, water from a precipitation event or snowmelt, which can be separated from the remainder of the hydrograph. Measurements of hydraulic conductivity, soil moisture content, soil temperature, and groundwater table level indicate that the major portion of the event water causing this effect infiltrates in the watershed recharge zone where soils are permeable, enters the weathered bedrock, flows preferentially and rapidly down the slope along disjoint fissures in the bedrock, finally emerging as ascending springs, and is, for the most part, intercepted by the tile drainage systems. Copyright © 2011 John Wiley & Sons, Ltd.
Distributed rainfall‐runoff modelling for flood frequency estimation and flood forecasting
Authors: Brocca L. , Melone F. , Moramarco T. 
Published: February 2011

AbstractNowadays, in the scientific literature many rainfall‐runoff (RR) models are available ranging from simpler ones, with a limited number of parameters, to highly complex ones, with many parameters. Therefore, the selection of the best structure and parameterisation for a model is not straightforward as it is dependent on a number of factors: climatic conditions, catchment characteristics, temporal and spatial resolution, model objectives, etc. In this study, the structure of a continuous semi‐distributed RR model, named MISDc (‘Modello Idrologico Semi‐Distribuito in continuo’) developed for flood simulation in the Upper Tiber River (central Italy) is presented. Most notably, the methodology employed to detect the more relevant processes involved in the modelling of high floods, and hence, to build the model structure and its parameters, is developed. For this purpose, an intense activity of monitoring soil moisture and runoff in experimental catchments was carried out allowing to derive a parsimonious and reliable continuous RR model operating at an hourly (or smaller) time scale. Specifically, in order to determine the catchment hydrological response, the important role of the antecedent wetness conditions is emphasized. The application of MISDc both for design flood estimation and for flood forecasting is reported here demonstrating its reliability and also its computational efficiency, another important factor in hydrological practice. As far as the flood forecasting applications are concerned, only the accuracy of the model in reproducing discharge hydrographs by assuming rainfall correctly known throughout the event is investigated indepth. In particular, the MISDc has been implemented in the framework of Civil Protection activities for the Upper Tiber River basin. Copyright © 2011 John Wiley & Sons, Ltd.
The relative impact of climate change and urban expansion on peak flows: a case study in central Belgium
Authors: Poelmans Lien , Rompaey Anton Van , Ntegeka Victor , Willems Patrick 
Published: February 2011

AbstractAn essential part of hydrological research focuses on hydrological extremes, such as river peak flows and associated floods, because of their large impact on economy, environment, and human life. These extremes can be affected by potential future environmental change, including global climate change and land cover change. In this paper, the relative impact of both climate change and urban expansion on the peak flows and flood extent is investigated for a small‐scale suburban catchment in Belgium. A rainfall‐runoff model was coupled to a hydrodynamic model in order to simulate the present‐day and future river streamflow. The coupled model was calibrated based on a series of measured water depths and, after model validation, fed with different climate change and urban expansion scenarios in order to evaluate the relative impact of both driving factors on the peak flows and flood extent. The three climate change scenarios that were used (dry, wet winter, wet summer) were based on a statistical downscaling of 58 different RCM and GCM scenario runs. The urban expansion scenarios were based on three different urban growth rates (low, medium, high urban expansion) that were set up by means of an extrapolation of the observed trend of urban expansion. The results suggest that possible future climate change is the main source of uncertainty affecting changes in peak flow and flood extent. The urban expansion scenarios show a more consistent trend. The potential damage related to a flood is, however, mainly influenced by land cover changes that occur in the floodplain. Copyright © 2011 John Wiley & Sons, Ltd.
High‐resolution monitoring reveals dissolved oxygen dynamics in an Antarctic cryoconite hole
Authors: Bagshaw E. A. , Tranter M. , Wadham J. L. , Fountain A. G. , Mowlem M. 
Published: February 2011

AbstractThis study presents the first high‐resolution dataset of dissolved oxygen (DO) measurements in an ice‐lidded cryoconite hole on Canada Glacier, McMurdo Dry Valleys, Antarctica. Fibre optic DO minisensors were installed in a cryoconite hole prior to seasonal internal melting and hydrological connection to the subsurface drainage system. Oxygen air saturation in the cryoconite hole typically ranged from 50 to 80%, in broad agreement with previous single measurements, indicating net respiration (R). This is consistent with results of simple incubation experiments performed in the field. Simultaneous time series for electrical conductivity, water temperature, and DO over the four‐week study period provide information regarding the connectivity of cryoconite holes with the near‐surface drainage system. The main driver of the observed variations in DO is likely to be periodic melt‐freeze cycles. We conclude that automated sensing techniques, such as those described here, when used in conjunction with physical measurements, have great potential for high‐resolution monitoring of the factors that perturb biogeochemical processes in cryospheric surface aquatic ecosystems. Copyright © 2011 John Wiley & Sons, Ltd.
Contribution of climatic and anthropogenic effects to the hydric deficit of peatlands
Authors: Auterives Chrystelle , Aquilina Luc , Bour Olivier , Davranche Mélanie , Paquereau Valérie 
Published: February 2011

AbstractThe present study makes use of a detailed water balance to investigate the hydrological status of a peatland with a basal clay‐rich layer overlying an aquifer exploited for drinking water. The aim is to determine the influence of climate and groundwater extraction on the water balance and water levels in the peatland. During the two‐year period of monitoring, the hydrological functioning of the wetland showed a hydric deficit, associated with a permanent unsaturated layer and a deep water table. At the same time, a stream was observed serving as a recharge inflow instead of draining the peatland, as usually described in natural systems. Such conditions are not favourable for peat accumulation. Field investigations show that the clay layer has a high hydraulic conductivity (from 1·10−7 to 3·10−9 m.s−1) and does not form a hydraulic barrier. Moreover, the vertical hydraulic gradients are downward between the peat and the sand aquifer, leading to high flows of groundwater through the clay layer (20–48% of the precipitation). The observed hydric deficit of the peatland results from a combination of dry climatic conditions during the study period and groundwater extraction. The climatic effect is mainly expressed through drying out of the peatland, while the anthropogenic effect leads to an enhancement of the climatic effect on a global scale, and a modification of fluxes at a local scale. The drying out of the peatland can lead to its mineralisation, which thus gives rise to environmental impacts. The protection of such wetlands in the context of climate change should take account of anthropogenic pressures by considering the wetland‐aquifer interaction. Copyright © 2011 John Wiley & Sons, Ltd.
A sensor array system for profiling moisture in unsaturated rock and soil
Authors: Salve Rohit 
Published: February 2011

AbstractAs the scope of hydrologic investigations extend deeper into the subsurface profile, and increasingly include fractured rock, there is a growing need for techniques that can accurately monitor saturation changes at a high spatial and temporal resolution in this environment. We have developed a technique, the Electrical Resistance Sensor Array System (ERSAS), to track moisture dynamics in vadose zone regions that include both fractured rock and soil. The performance of ERSAS was compared with the time domain reflectometry (TDR) technique under controlled and field conditions. We found that ERSAS was effective in determining patterns of saturation changes along vertical soil/rock profiles. Because of the small size of individual sensors, it was able to resolve travel times associated with a wetting front and peak saturation better than TDR. In addition, ERSAS is significantly cheaper than the TDR system, and the sensor arrays are relatively easier to install in the subsurface profile. Published in 2011 by John Wiley & Sons, Ltd.
The composition of the debtor's estate on insolvency: A comparative study of exemptions
Authors: Skene Donna McKenzie 
Published: February 2011

AbstractThis article examines one aspect of the issue of the composition of the debtor's estate on insolvency, namely the exemption of certain assets from the debtor's estate. It sets out the responses to a questionnaire completed by leading scholars in selected jurisdictions (Australia, Canada, France, Italy, New Zealand, South Africa, The Netherlands and the USA) on the exemptions available in those jurisdictions, makes preliminary observations on those responses, considers the prospects for harmonisation of this area of law in the light of those observations and puts forward some tentative proposals for the development of model provisions and/or legislative principles in the area of exemptions for comment and discussion. Copyright © 2011 John Wiley & Sons, Ltd.
Towards Arithmetic Circuits in Sub‐Excitable Chemical Media
Authors: Adamatzky Andrew , De Lacy Costello Ben , Bull Larry , Holley Julian 
Published: February 2011

AbstractA sub‐excitable Belousov–Zhabotinsky medium exhibits localized travelling excitations (in contrast to an excitable medium exhibiting target or spiral waves). Initially assymetric perturbations give birth to excitation wave‐fragments. The shape and velocity vectors of the wave‐fragments are conserved, meaning they can travel for substantial distances in the reaction media. When the wave‐fragments collide they may reflect, merge, or annihilate. We interpret wave‐fragments as values of logical variables, and the post‐collision states of the fragments as outputs of logical gates. We show how to cascade logical gates in primitive arithmetical circuits.
A semi‐degradable composite scaffold for articular cartilage defects
Authors: Scholten Paul M. , Ng Kenneth W. , Joh Kiwon , Serino Lorenzo P. , Warren Russell F. , Torzilli Peter A. , Maher Suzanne A. 
Published: February 2011

AbstractFew options exist to replace or repair damaged articular cartilage. The optimal solution that has been suggested is a scaffold that can carry load and integrate with surrounding tissues; but such a construct has thus far been elusive. The objectives of this study were to manufacture and characterize a nondegradable hydrated scaffold. Our hypothesis was that the polymer content of the scaffold can be used to control its mechanical properties, while an internal porous network augmented with biological agents can facilitate integration with the host tissue. Using a two‐step water‐in‐oil emulsion process a porous polyvinyl alcohol (PVA) hydrogel scaffold combined with alginate microspheres was manufactured. The scaffold had a porosity of 11–30% with pore diameters of 107–187 μm, which readily allowed for movement of cells through the scaffold. Alginate microparticles were evenly distributed through the scaffold and allowed for the slow release of biological factors. The elastic modulus (Es) and Poisson's ratio (υ), Aggregate modulus (Ha) and dynamic modulus (ED) of the scaffold were significantly affected by % PVA, as it varied from 10 to 20% wt/vol. Es and υ were similar to that of articular cartilage for both polymer concentrations, while Ha and ED were similar to that of cartilage only at 20% PVA. The ability to control scaffold mechanical properties, while facilitating cellular migration suggest that this scaffold is a potentially viable candidate for the functional replacement of cartilage defects. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Probing orientation of immobilized humanized anti‐lysozyme variable fragment by time‐of‐flight secondary‐ion mass spectrometry
Authors: Baio J. E. , Cheng Fang , Ratner Daniel M. , Stayton Patrick S. , Castner David G. 
Published: February 2011

AbstractAs methods to orient proteins are conceived, techniques must also be developed that provide an accurate characterization of immobilized protein orientation. In this study, X‐ray photoelectron spectroscopy (XPS), surface plasmon resonance (SPR), and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) were used to probe the orientation of a surface immobilized variant of the humanized anti‐lysozyme variable fragment (HuLys Fv, 26 kDa). This protein contained both a hexahistidine tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo(ethylene glycol) (MEG)‐terminated substrates, respectively. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his‐tag selectively binds to the Ni‐loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. SPR results showed a 10‐fold difference in lysozyme binding between the two different HuLys Fv orientations. The ToF‐SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv (histidine: 81, 82, and 110 m/z; phenylalanine: 120 and 131 m/z). An intensity ratio of the secondary ion peaks from the histidine and phenylalanine residues at either end of the protein was then calculated directly from the ToF‐SIMS data. The 45% change in this ratio, observed between the NTA and MEG substrates with similar HuLys Fv surface coverages, indicates that the HuLys Fv fragment has opposite orientations on two different surfaces. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
An in vitro study of blood compatibility of vascular grafts made of bacterial cellulose in comparison with conventionally‐used graft materials
Authors: Fink Helen , Hong Jaan , Drotz Kristoffer , Risberg Bo , Sanchez Javier , Sellborn Anders 
Published: February 2011

AbstractIn this study we analyzed the blood compatibility of bacterial cellulose (BC) as a new biosynthetic material for use as a vascular graft. As reference materials we used expanded polytetrafluoroethylene (ePTFE) and poly(ethylene terephthalate) (PET) vascular grafts. These materials are in clinical use today. Tubes with inner diameters of both 4 (not PET) and 6 mm were tested. Heparin‐coated PVC tubes (hepPVC) were used as a negative control. Platelet consumption and thrombin‐antithrombin complex (TAT) were used as parameters of coagulation and for complement activation, sC3a and sC5b‐9 were used. The investigated parameters were measured after 1‐h exposure to freshly drawn human blood supplemented with a low dose of heparin in a Chandler loop system. The results showed that BC exhibits no significant difference in platelet consumption, as compared with PET (6 mm), ePTFE and hepPVC. The PET material consumed more platelets than any of the other materials. The TAT generation for 4 mm tubes was not significantly different between BC and the other materials. For 6 mm tubes, however, differences were observed between hepPVC and PET (p < 0.0001); BC and hepPVC (p = 0.0016); ePTFE and PET (p < 0.0001); BC and ePTFE (p = 0.0029); BC and PET (p = 0.0141). Surprisingly, considering the low platelet consumption, the complement activation parameters (sC3a and sC5b‐9) were much higher for BC, as compared with the other materials for both 4 and 6 mm tubes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.