bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydraulic modelling of fish habitat in urban rivers during high flows
Authors: Booker D. J. 
Published: January 2003

AbstractIn urban rivers, flow regime and channel morphology are the drivers of physical habitat quality for aquatic species. Peak discharges are increased at high flows as a result of impermeable catchments and channel engineering for flood protection schemes. Hazardous conditions and flashy hydrographs mean that measurement of velocities at high flows is a difficult task. This research uses a three‐dimensional computational fluid dynamics (3D‐CFD) model to simulate hydraulic patterns in two urban river channels. A 3D‐CFD code, called SSIIM, was used to simulate hydraulic conditions in two engineered river reaches of the River Tame, Birmingham, UK. These two sites represent channels with different levels of engineering. Models were calibrated and tested using field measurements. Results show that modelled water surface levels and velocity profiles are well simulated. Calibrated roughness heights are compared with those derived from field measurement of sediment size. Numerical experiments are used to assess the relationship between grid resolution in the vertical dimension and the form of the modelled velocity profiles. Biologists have used laboratory experiments to determine maximum sustainable swimming speeds (MSSS) of fish, often in order to assess what level of a particular pollutant may be tolerable. In this work, simulations of high‐flow hydraulic patterns are used to compare velocity patterns with fish MSSS. Results show that when the water levels rise to fill the first channel of the two‐stage channels at the sites, which occurred 16 times in 2000, MSSS are surpassed in the majority of available habitat, suggesting that excessive velocities at high flows are one factor that limits fish habitat. A comparison between the two reaches shows that there is less available habitat in the more modified reach. Conclusions suggest that an approach that integrates water quality issues and physical channel characteristics must be taken in river rehabilitation schemes, as improvements to water quality alone may not be sufficient to improve habitat quality to the desired level. Copyright © 2002 John Wiley & Sons, Ltd.
Measurements of rain splash on bench terraces in a humid tropical steepland environment
Authors: Van Dijk A. I. J. M. , Bruijnzeel L. A. , Wiegman S. E. 
Published: January 2003

AbstractSoil loss continues to threaten Java's predominantly bench‐terraced volcanic uplands. Sediment transport processes on back‐sloping terraces with well‐aggregated clay‐rich oxisols in West Java were studied using two different techniques. Splash on bare, cropped, or mulched sub‐horizontal (2–3°) terrace beds was studied using splash cups of different sizes, whereas transport of sediment on the predominantly bare and steep (30–40/deg ) terrace risers was measured using a novel device combining a Gerlach‐type trough with a splash box to enable the separate measurement of transport by wash and splash processes. Measurements were made during two consecutive rainy seasons. The results were interpreted using a recently developed splash distribution theory and related to effective rainfall erosive energy. Splash transportability (i.e. transport per unit contour length and unit erosive energy) on the terrace risers was more than an order of magnitude greater than on bare terrace beds (0·39–0·57 versus 0·013–0·016 g m J−1). This was caused primarily by a greater average splash distance on the short, steep risers (>11 cm versus c. 1 cm on the beds). Splashed amounts were reduced by the gradual formation of a protective ‘pavement’ of coarser aggregates, in particular on the terrace beds. Soil aggregate size exhibited an inverse relationship with detachability (i.e. detachment per unit area and unit erosive energy) and average splash length, and therefore also with transportability, as did the degree of canopy and mulch cover. On the terrace risers, splash‐creep and gravitational processes transported an additional 6–50% of measured rain splash, whereas transport by wash played a marginal role. Copyright © 2002 John Wiley & Sons, Ltd.
Heterogeneity in ground water–surface water interactions in the hyporheic zone of a salmonid spawning stream
Authors: Malcolm I. A. , Soulsby C. , Youngson A. F. , Petry J. 
Published: January 2003

AbstractSpatial and temporal variability in ground water–surface water interactions in the hyporheic zone of a salmonid spawning stream was investigated. Four locations in a 150‐m reach of the stream were studied using hydrometric and hydrochemical tracing techniques. A high degree of hydrological connectivity between the riparian hillslope and the stream channel was indicated at two locations, where hydrochemical changes and hydraulic gradients indicated that the hyporheic zone was dominated by upwelling ground water. The chemistry of ground water reflected relatively long residence times and reducing conditions with high levels of alkalinity and conductivity, low dissolved oxygen (DO) and nitrate. At the other locations, connectivity was less evident and, at most times, the hyporheic zone was dominated by downwelling stream water characterized by high DO, low alkalinity and conductivity. Substantial variability in hyporheic chemistry was evident at fine (<10 m) spatial scales and changed rapidly over the course of hydrological events. The nature of the hydrochemical response varied among locations depending on the strength of local ground water influence. It is suggested that greater emphasis on spatial and temporal heterogeneity in ground water–surface water interactions in the hyporheic zone is necessary for a consideration of hydrochemical effects on many aspects of stream ecology. For example, the survival of salmonid eggs in hyporheic gravels varied considerably among the locations studied and was shown to be associated with variation in interstitial chemistry. River restoration schemes and watershed management strategies based only on the surface expression of catchment characteristics risk excluding consideration of potentially critical subsurface processes. Copyright © 2002 John Wiley & Sons, Ltd.
Comparing the hydrology of grassed and cultivated catchments in the semi‐arid Canadian prairies
Authors: van der Kamp G. , Hayashi M. , Gallén D. 
Published: January 2003

AbstractAt the St Denis National Wildlife Area in the prairie region of southern Saskatchewan, Canada, water levels in wetlands have been monitored since 1968. In 1980 and 1983 a total of about one‐third of the 4 km2 area was converted from cultivation to an undisturbed cover of brome grass. A few years after this conversion all the wetlands within the area of grass dried out; they have remained dry since, whereas wetlands in adjacent cultivated lands have held water as before. Field measurements show that introduction of undisturbed grass reduces water input to the wetlands mainly through a combination of efficient snow trapping and enhanced infiltration into frozen soil. In winter, the tall brome grass traps most of the snowfall, whereas in the cultivated fields more wind transport of snow occurs, especially for short stubble and fallow fields. Single‐ring infiltration tests were conducted during snowmelt, while the soil was still frozen, and again in summer. The infiltrability of the frozen soil in the grassland is high enough to absorb most or all of the snowmelt, whereas in the cultivated fields the infiltration into the frozen soil is limited and significant runoff occurs. In summer, the infiltrability increases for the cultivated fields, but the grassland retains a much higher infiltrability than the cultivated land. The development of enhanced infiltrability takes several years after the conversion from cultivation to grass, and is likely due to the gradual development of macropores, such as root holes, desiccation cracks, and animal burrows. Copyright ©2002 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Improving peak flow estimates in artificial neural network river flow models
Authors: Sudheer K. P. , Nayak P. C. , Ramasastri K. S. 
Published: January 2003

AbstractIn this paper, the concern of accuracy in peak estimation by the artificial neural network (ANN) river flow models is discussed and a suitable statistical procedure to get better estimates from these models is presented. The possible cause for underestimation of peak flow values has been attributed to the local variations in the function being mapped due to varying skewness in the data series, and theoretical considerations of the network functioning confirm this. It is envisaged that an appropriate data transformation will reduce the local variations in the function being mapped, and thus any ANN model built on the transformed series should perform better. This heuristic is illustrated and confirmed by many case studies and the results suggest that the model performance is significantly improved by data transformation. The model built on transformed data outperforms the model built on raw data in terms of various statistical performance indices. The peak estimates are improved significantly by data transformation. Copyright © 2003 John Wiley & Sons, Ltd.
Design and use of multi‐affinity surfaces in biomolecular interaction analysis–mass spectrometry (BIA/MS): a step toward the design of SPR/MS arrays
Authors: Nedelkov Dobrin , Nelson Randall W. 
Published: January 2003

AbstractThe feasibility of multi‐affinity ligand surfaces in biomolecular interaction analysis–mass spectrometry (BIA/MS) was explored in this work. Multi‐protein affinity surfaces were constructed by utilizing antibodies to beta‐2‐microglobulin, cystatin C, retinol binding protein, transthyretin, serum amyloid P and C‐reactive protein. In the initial experiments, all six antibodies were immobilized on a single site (flow cell) on the sensor chip surface, followed by verification of the surface activity via separate injections of purified proteins. After an injection of diluted human plasma aliquot over the antibodies‐derivatized surfaces, and subsequent MALDI‐TOF MS analysis, signals representing five out of the six targeted proteins were observed in the mass spectra. Further, to avoid the complexity of the spectra, the six proteins were divided into two groups (according to their molecular weight) and immobilized on two separate surfaces on a single sensor chip, followed by an injection of human plasma aliquot. The resulting mass spectra showed signals from all proteins. Also, the convolution resulting from the multiply charged ion species was eliminated. The ability to create such multi‐affinity surfaces indicates that smaller‐size ligand areas/spots can be employed in the BIA/MS protein interaction screening experiments, and opens up the possibilities for construction of novel multi‐arrayed SPR‐MS platforms and methods for high‐throughput parallel protein interaction investigations. Copyright © 2003 John Wiley & Sons, Ltd.
Human CD30: Structural implications from epitope mapping and modeling studies
Authors: Dong Liying , Hülsmeyer Martin , Dürkop Horst , Hansen Hinrich P. , Schneider‐Mergener Jens , Ziegler Andreas , Uchanska‐Ziegler Barbara 
Published: January 2003

AbstractThe human CD30 molecule is expressed transiently at very low levels on intrafollicular and perifollicular T and B cell blasts in lymphoid tissues, but is specifically upregulated on certain tumor cells, e.g. Hodgkin and Reed–Sternberg (H‐RS) cells. With its specific expression pattern and easy accessibility on the surface of H‐RS cells CD30 is a valuable diagnostic marker and holds considerable promise as a target for in vivo immunotherapy. Knowledge of epitopes on the CD30 molecule is expected to facilitate the design of novel non‐immunogenic anti‐CD30 reagents. Therefore, we have mapped the epitopes of several monoclonal antibodies (mAb) applying a peptide array of overlapping CD30‐derived peptides. For the mAb Ber‐H2, two linear epitopes with identical sequence were found, while the mAb Ki‐2 and the single chain Fv fragment R4‐4 each recognized a single linear antigenic determinant, respectively. On the other hand, the mAb Ki‐1 bound to a discontinuous epitope composed of two regions, one located near the N‐terminus and the other near the membrane‐spanning region of CD30. Using molecular modeling, it was possible to visualize the location of the epitopes on exposed loop regions of the molecule within the N‐terminal domain. Finally, the results obtained with the mAb Ki‐1 imply that the ends of the N‐ and C‐terminal parts of the extracellular portion of CD30 are in close vicinity of each other, suggesting a flower‐like structure for the membrane‐bound homotrimeric CD30 molecule. Copyright © 2003 John Wiley & Sons, Ltd.
Teleconnections between Indian monsoon and Sahel rainfall and the Mediterranean
Authors: Raicich Fabio , Pinardi Nadia , Navarra Antonio 
Published: January 2003

AbstractThe teleconnections with Indian monsoon and Sahel rainfall indices are investigated here on an interannual time scale in terms of meteorological and marine dynamics over the Mediterranean area. Sea‐level pressure from gridded data sets and from individual stations, together with sea‐level data from stations all around the Mediterranean coastlines, are used.In summer (July–August–September, JAS) the sea‐level pressure field over the eastern Mediterranean anticorrelates with the Indian monsoon index (correlation coefficient C = −0.5 on average). A Mediterranean pressure index (MPI), defined as the standardized difference between sea‐level atmospheric pressure at Mersa Matruh (southeastern Mediterranean) and Marseille (northwestern Mediterranean) stations, anticorrelates with Indian monsoon index even more (C = −0.68). The MPI is proportional to the mean geostrophic surface flow field across an imaginary line joining the two stations and turns out to be significantly correlated with the meridional wind component over the eastern Mediterranean, known as the low‐level Etesian wind regime. This wind regime represents the inflow surface field into the African inter‐tropical convergence zone and, therefore, has an association with the Indian monsoon regime. The ocean response, evident by sea‐level anomalies at coastal stations, shows a maximum anticorrelation with Indian monsoon index in late summer and autumn (September–October–November, SON).The Sahel index anticorrelates with sea‐level pressure, with the maximum absolute value in June–July–August. This may be interpreted as a tendency of the Mediterranean sea‐level pressure anomalies to precede those of Sahel precipitation, which is characterized by maximum rainfall in July–September. The MPI anticorrelates with Sahel index during and before JAS, indicating that the Etesian wind regime intensity is connected to Sahel rainfall. The sea level again anticorrelates with the Sahel index, with the maximum absolute value in SON, as for the sea‐level–Indian monsoon correlation. Copyright © 2003 Royal Meteorological Society.
Impact of El Niño–southern oscillation on Indian foodgrain production
Authors: Selvaraju R. 
Published: January 2003

AbstractThe impact of El Niño–southern oscillation (ENSO) on Indian foodgrain production was analysed for the period 1950–99. The inverse relationship between sea‐surface temperature (SST) anomalies from June to August (JJA) over the NINO3 sector of the tropical Pacific Ocean and Indian foodgrain production anomalies (r = −0.50) was significant at the 1% level. During the warm ENSO phase, the total foodgrain production frequently decreased (12 out of 13 years) by 1 to 15%. In 10 out of 13 cold ENSO‐phase years, the total foodgrain production increased from normal. The relationship between the SST‐based NINO3 ENSO index and the Kharif season (June–September) foodgrain production anomalies (r = −0.52) was greater than for the Rabi season (October–February) foodgrain production (r = −0.27). The ENSO impact on rice production was greatest among the individual crops. The average drop in rice (Kharif season crop) production during a warm ENSO‐phase year was 3.4 million tonnes (7%). In a cold ENSO‐phase year the average production increase was 1.3 million tones (3%). Wheat (Rabi season crop) production was also influenced by ENSO, as it depends on the carryover soil water storage from the Kharif season. Sorghum and chickpea production are not significantly influenced by ENSO extremes.Inter‐annual fluctuation of the gross value of Indian foodgrain production was very large, reducing up to US$2183 million in a warm ENSO year and increasing up to US$1251 million in a cold ENSO year. On average, a warm ENSO year costs US$773 million and a cold ENSO year had a financial gain of US$437 million from normal.The cumulative probability distributions of foodgrain production anomalies during cold and warm ENSO phases are shifted positively or negatively, relative to the neutral distribution. The warm ENSO forcing significantly (1% level) reduced the probability of above‐average production. The cold ENSO forcing moderately increased the above‐average foodgrain production over the neutral ENSO phase (5% level). A simple conditional probability forecast based on annual and JJA NINO3 SST predicted the category of foodgrain production in 11 of the 14 years. The results demonstrated that the relationship between NINO3 ENSO index and foodgrain production could be used for agricultural applications and policy decisions on food security for the rapidly growing population in India. Copyright © 2003 Royal Meteorological Society.
Precipitation trends in the Canary Islands
Authors: García‐Herrera Ricardo , Gallego David , Hernández Emiliano , Gimeno Luis , Ribera Pedro , Calvo Natalia 
Published: January 2003

AbstractA strong decreasing trend in the Canary Islands' precipitation is detected by studying daily rainfall time series for the second half of the 20th century. An analysis of the extreme events shows that this trend is due mainly to a decrease in the upper percentiles of the precipitation distribution. The results suggest that local factors play a fundamental role on extreme event behaviour. Copyright © 2003 Royal Meteorological Society.
The relationship between land use and soil erosion in the communal lands near Peddie town, Eastern Cape, South Africa
Authors: Kakembo V. , Rowntree K. M. 
Published: January 2003

AbstractThe origins and development of severe forms of erosion are traced in the communal villages located in a part of the dividing ridge between the Great Fish and Keiskamma rivers near Peddie town, Eastern Cape, South Africa. Progressive changes in land use and soil erosion distribution are reconstructed by analysing sequential aerial photographs of the area between 1938 and 1988. The distributions of the two phenomena are mapped and quantified at the different dates using PC ARC/INFO GIS. Observable soil erosion is confined to the communal lands at all the dates. Widespread abandonment of cultivated fields between 1965 and 1988 is noted as the most significant aspect of land use change in the communal lands. Gully initiation and intensification appear predominantly from the mid‐1970s, coinciding with a period of extreme rainfall events. A close spatial correlation between abandoned cultivated land and severe gullies is identified. The research raises questions regarding both the cause for land abandonment and the reasons for its vulnerability to erosion. The observed land degradation is seen as the result of a complex interaction of social, economic and environmental factors which lead to land abandonment and its consequent erosion. Copyright © 2002 John Wiley & Sons, Ltd.
Assessment of certain soil properties related to different land‐use systems in the Kaya watershed of the humid forest zone of Cameroon
Authors: Voundi Nkana J. C. , Tonye J. 
Published: January 2003

AbstractA field survey was conducted in the Kaya watershed of the humid forest zone of Cameroon to assess changes in particle size distribution and chemical soil properties related to different land‐use systems. The strongly acid soils are mainly composed of sand and clay, and are poor in organic carbon, total nitrogen, mineral nutrients and effective cation exchange capacity (ECEC), with the major portion of nutrients stored in the topsoil, together with organic matter. Land‐use systems significantly affect the sand and the clay fractions and have high proportions of sand in soils of cropped fields, secondary forest and river valleys and high clay percentages under dense forest and fallows. Soil pH and exchangeable Al in the topsoil and the subsoil, organic carbon, available P, base saturation and Al saturation in the topsoil and ECEC in the subsoil significantly differ with the land‐use systems. Soils of food‐crop fields and river valleys presented a higher fertility level than under secondary and dense forests. Permanent vegetation coverage and/or exposure to heavy rains of the soils, disturbance due to land preparation, organic matter supplied by the vegetation, nutrient cycling, nutrient restitution and nutrient uptake could be differentiation factors. For agricultural development, utilization of residue from harvest to cover the soil surface, liming and P fertilization appeared as the first and the most important management options. Nitrogen and K fertilization could be added according to crop requirements. Since farmers cannot afford to buy lime and mineral fertilizers and agroforestery is hardly practised, the utilization of cheap and widely available wood ash as a liming agent and supplier of P and K is a promising option. Field trials at the farmer level are proposed to evaluate this. Copyright © 2002 John Wiley & Sons, Ltd.
Soil erosion, indigenous irrigation and environmental sustainability, Marakwet, Kenya
Authors: Adams W. M. , Watson E. E. 
Published: January 2003

AbstractIrrigation developed indigenously has long been practised on the Western rift escarpment of the Kerio Valley in Kenya by the Marakwet people. Outsiders have often remarked on the problem of soil erosion, and suggested that the irrigation practices are unsustainable. This article discusses local and outside perceptions of soil erosion under irrigation, and their implications for assessing the sustainability of indigenous irrigation. It argues that erosion is taking place, but that local farmers do not perceive erosion as such as a critical challenge to their farming activities. Copyright © 2002 John Wiley & Sons, Ltd.