bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linkage of slope wash and sediment and solute export from a foothill catchment in the Carpathian Foothills of South Poland
Authors: Święchowicz Jolanta 
Published: December 2002

AbstractThis paper analyses the linkage between slope wash and sediment and solute export from the Stara Rzeka foothill catchment. Transport of sediment on slopes and its supply to the stream channel vary in time and depend on morphology and agricultural use of the area. Three thresholds important for morphodynamics in a foothill catchment have been established as well as the role of slopes and valley bottoms in the supply of suspended matter to stream channels. When the first threshold is exceeded, occasional transport of material on a particular slope is initiated. When the second threshold is exceeded, local erosion is triggered on a slope. When the third threshold is exceeded, general transport of material on a slope takes place and is deposited in the valley bottom. When the second threshold is exceeded, the linkage between the slope and the channel is local. When the third threshold is exceeded, the connection between the two systems is general but still the majority of material transported from the slope is deposited on the footslope proluvial plains and in flat valley bottoms.In the Stara Rzeka foothill catchment, chemical denudation is dominant. However, the proportion of solute and sediment export is significantly larger in its subcatchment. This indicates that proluvial plains impede free sediment flux from the watershed divide to the channel and also that the solute transported by streams comes from the whole area of the catchment, while the source of the sediment is channel erosion. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of soil‐loss contribution areas on loess soils in SouthEast Poland
Authors: Rejman Jerzy , Usowicz Bogusław 
Published: December 2002

AbstractResults of soil‐loss assessments on loess‐derived silt soils are presented. The studies were conducted on plots of different length maintained in continuous bare fallow conditions. Analysing runoff events separately, soil losses per unit area varied with plot length. Description of the soil‐erosion process in terms of (1) maximum soil loss per unit area and (2) the effective distance of soil transport allows us to overcome problems with data interpretation. Smaller values of soil loss per unit area could then be connected with (1) impeded development of erosion process on plots of shorter length and (2) over‐estimation of soil loss contribution area on longer plots. The method of determination of soil‐loss contribution area was the main reason of the differences between soil losses, observed and predicted from the Universal Soil Loss Equation. Studies conducted showed that eroded soil material was transported short distances (from 2 to 13 m). The maximum soil loss per unit area was well correlated with rainfall amount, whilst the effective distance of soil transport was affected by many factors, including rainfall amount and initial state of soil roughness. Copyright © 2002 John Wiley & Sons, Ltd.
Using sediment deposits in small ponds to quantify sediment yield from small catchments: possibilities and limitations
Authors: Verstraeten Gert , Poesen Jean 
Published: December 2002

AbstractMost soil‐erosion research has been undertaken at small spatial scales, i.e. from small erosion plots over field parcels to small catchments of a few hectares. On the other hand, sediment‐yield data for several large river basins (>1000 km2) are also available. Little information exists, however, on the link between soil‐erosion processes on hillslopes and yields of suspended sediment in large rivers. Data on sediment yield for smaller catchments (1–50 km2) are therefore needed. Such data can be obtained by different measuring methods of which sediment rating curves or river sampling are the most common. In this study, however, the possibilities and limitations of the use of sedimentary deposits in small ponds (<1 ha) to assess sediment yields is investigated. In small catchments (<50 km2), many small flood retention ponds, ponds for irrigation purposes or farm ponds already exist and no expensive monitoring equipment needs to be installed to assess sediment yield. This technique, however, also has a few limitations. Volumetric sediment deposition rates measured in these ponds need to be converted to sediment masses using representative values of the dry sediment bulk density. Furthermore, measured sediment masses need to be corrected for the trap efficiency of the pond otherwise sediment yield will be underestimated. These conversions and corrections are subject to errors. For 21 catchments in central Belgium, the mean error on computed sediment yield, using sediment deposits in small ponds, was estimated to range between 40 and 50 per cent. This error more or less corresponds to the error when using sediment rating curves and suggests that this technique can be a valuable alternative to provide data on the regional variations in sediment yield. Copyright © 2002 John Wiley & Sons, Ltd.
Modelling the effects of hillslope–channel coupling on catchment hydrological response
Authors: Michaelides Katerina , Wainwright John 
Published: December 2002

AbstractA new two‐dimensional hydrological model has been developed that accounts for dynamic interactions between hillslope and channel flows. The model is specifically designed for semi‐arid areas dominated by Hortonian overland flow, and has a dynamically active channel belt. Sensitivity analyses of the model have been carried out to assess the relative importance of topographic linkages, surface characteristics and rainfall characteristics on catchment hydrological response. Attribute sensitivity analyses suggest that hillslopes are more sensitive than floodplains to all parameters except surface roughness. However, decoupling through the presence of floodplains or other barriers will reduce the relative importance of the sensitivity of hillslope parameters. Spatial sensitivity analysis suggests that sensitivity to the spatial variability of infiltration decreases with an increase in the magnitude of the runoff event. On the other hand, variability in output discharge at the catchment outlet increases with an increase in the spatial variability of infiltration. Rainfall intensity is thus an important factor in controlling the overall coupling characteristics. Catchment runoff production is affected by a complex interaction of topographic, surface and rainfall characteristics. Copyright © 2002 John Wiley & Sons, Ltd.
The influence of land use, soils and topography on the delivery of hillslope runoff to channels in SE Spain
Authors: Kirkby Mike , Bracken Louise , Reaney Sim 
Published: December 2002

AbstractIt is generally accepted that within particular physiographic and climatic regions catchments exhibit differences in their hydrological response. These differences result from the interaction of spatial variability in catchment characteristics, variability of rainfall inputs and surface and subsurface hydrological processes. These interactions are complex and difficult to unravel. Hydrologically similar surfaces (HYSS) have been used to identify catchment areas that have a similar response to rainfall and have been identified at a number of scales. HYSS have been identified at the subcatchment scale for the Rambla de Nogalte in SE Spain. Areas with similar at‐a‐point hydrological storages were distinguished by using a combination of geology, land use and topography. This mapping was compared with discharge estimates made throughout the catchment following a seven‐year return interval flood in September 1997. From this significant flood source areas were identified from reaches showing rapidly increasing channel discharge, and associated with HYSS that combined suitable internal characteristics with good connectivity to the main channel. This paper presents a simulation model that has been developed to investigate the way in which the hydrological response of areas within a HYSS respond to changes in source area, gradient, connectivity to the channel, storm size and intensity profile. This is one of the first studies using a hillslope model to investigate spatial patterns of runoff‐response in semi‐arid areas and results have implications for scaling up hydrological response, and on how the dynamics of runoff producing areas vary both under changing storm conditions and over time. It is implicit in our results that the nature of stream–slope coupling differs substantively between semi‐arid and humid areas. Copyright © 2002 John Wiley & Sons, Ltd.
Modelling solute and sediment transport at different spatial and temporal scales
Authors: Bogena Heye R. , Diekkrüger Bernd 
Published: December 2002

AbstractA concept for continuous modelling of solute and sediment transport at the catchment scale for a period of 50 years is presented. The simulation is based on the application of the OPUS model system, which is designed for long‐term simulations of agricultural processes. As OPUS is a hillslope model, the catchment is discretized into numerous slopes. Modifications and enhancements of the OPUS model were made in order to simulate interflow induced by macropores. The simulation results are compared with measurements at different spatial and temporal scales of a meso‐scale catchment used for drinking water supply. Five small subcatchments of 22 to 29 ha are used to validate the model at the local scale. The modified and validated model is then applied to the Wahnbach catchment with an area of about 54 km2. Simulations at the local and the catchment scales are presented and compared with measurements.To model the long‐term behaviour of solute and sediment transport with a deterministic model, a complete set of climate and land‐use data is necessary. In this case study a method was developed to overcome the lack of data by using a weather generator. The long‐term catchment simulations are validated by determining the mass of sediments trapped in the drinking‐water reservoir. The results confirm that the model concept is applicable to a large range of scales from single events to decades and from single slopes to meso‐scale catchments. By using these methods it is conceivable to make forecast simulations of the future solute and sediment discharge using land‐use scenarios. Copyright © 2002 John Wiley & Sons, Ltd.
A new juniper from the Palaeogene of Central Europe
Authors: Kvaček Z. 
Published: December 2002

AbstractThe earliest fossil record of Juniperus L. (Cupressaceae) is reported. Juniperus pauli Z. Kvaček, sp. nova is based on foliage shoots, pollen cones, seed cones and seeds, and belongs to the multiseed series of “entire”‐leafed species of sect. Sabina. It occurs in association with the humid warm‐temperate mixed‐mesophytic forest vegetation in the volcanogenic diatomaceous shale at Roudníky and Větruše in the Palaeogene of the České středohoří Mountains, north Bohemia. The former site is radiometrically dated near the Eocene/Oligocene boundary. The relationship to extant taxa is discussed together with a review of fossil junipers.
Population variation in Persicaria salicifolia (Brouss. ex Willd.) Assenov (Polygonaceae) in Nigeria
Authors: Ayodele A. E. , Olowokudejo J. D. 
Published: December 2002

AbstractStudy of six living population samples and herbarium specimens of Persicaria salicifolia from Nigeria revealed considerable variability in vegetative and floral characters. Two subspecies, one of which is a new one (subsp. nova, p. 516), are recognised. Experimental cultivation showed that the combination of distinguishing characters for each subspecies remains intact under uniform conditions in the botanical nursery.
De Liliifloris Notulae – 7. De decuria altera specierum novarum generis Androcymbium (Colchicaceae) in Africa Australi s.l.
Authors: Müller‐Doblies Ute , Müller‐Doblies D. 
Published: December 2002

AbstractIn a previous paper (Müller‐Doblies 1998) we established a taxonomic framework for Androcymbium sect. Androcymbium by subdividing it into two subsections with two and six series respectively, comprising altogether 34 species. Apart from one monotypic series, the other seven series were foreseen to comprise 3–13 species, and the second largest series A. ser. Gradatocymbia was subdivided into four subseries.Encouraged by the molecular results of Caujapé Castells et al. (1999, 2001), we upgraded the two subsections of A. sect. Androcymbium to sectional level: A. subsect. Gradatocymbium became A. sect. Kunkeliocymbium with 16 spp. and the emended A. sect. Androcymbium s.str. now has 30 spp.The largest series A. ser. Eghimocymbia was already earmarked for a subdivision into subseries, a plan which is realized in the present paper. For another 10 new species (numbered # 11–# 20 in the present paper) diagnoses and drawings are given. Furthermore the postponed drawings of five new Androcymbium species described in Müller‐Doblies (1998) are added here. Eight of the present new spp. were collected alive in the field for cultivation, whereas each of the remaining two are only known from a herbarium specimen.For the presentation of distribution data, the geographic table for Southern Africa developed by Müller‐Doblies (1996) (refined by Müller‐Doblies et al. 2001) is used in Tables 5–7. After the inclusion of two Androcymbium species and one subspecies described by Pedrola Montfort et al. (1999a, b), the three distribution tables of Androcymbium in Southern Africa comprise 50 species [retaining the numbering 05–48 of Müller‐Doblies (1998) for Androcymbium sect. Androcymbium and including the new Pedrola species for the time being as 13A and 14A]. Thus, the current list of Southern African Androcymbium species embraces a total of 50 spp. in 11 series.Only two of the 50 Southern African Androcymbium species do not occur in the Republic of South Africa (RSA): i.e. the Namibian endemics A. etesionamibense and A. buchubergense. Of the remaining 48 Androcymbium species 38 are endemic to RSA. The 10 non‐endemic species occur in addition to RSA also in Namibia, or in Lesotho and/or Swaziland. The highest concentration of Androcymbium species is found in the Northern and the Western Cape: in each of them more than 50% of the 48 South African species occur (28 and 26 spp. respectively including 12 and 10 endemic spp.), whereas in the other seven provinces only 0–6 spp. occur of which only two species are endemic to Kwazulu‐Natal.
Originalité de la flore et de la végétation de l'Anti‐Atlas sud‐occidental (Maroc)
Authors: Msanda F. , El Aboudi A. , Peltier J.P. 
Published: December 2002

AbstractL'Anti‐Atlas occidental marocain se caractérise par des structures de végétation constituées à la fois par des éléments de souche méditerranéenne, saharienne et tropicale qui cohabitent en fonction des conditions climatiques. L'originalité du secteur tient à la présence du genre endémique Argania, d'éléments succulents, de Quercus ilex subsp. rotundifolia (qui trouve ici sa limite méridionale absolue au Maroc), d'un développement spectaculaire de la steppe à Artemisia inculta (qui annonce un domaine plus interne), d'une flore saharienne (sur le revers méridional) et de nombreuses endémiques. Les principales structures de végétation sont rappelées et leur ordonnancement précisé. En fonction de critères édapho‐géomorphologiques, diverses associations sahariennes ont été retrouvées et quelques nouvelles structures de végétation décrites. Le passage à la végétation saharienne se situe au nord du jbel Bani et correspond à l'isohyète des 100 mm. Toutes ces végétations se caractérisent par leur extrême dégradation, à l'origine souvent d'une uniformisation des paysages rendant difficile la reconnaissance des différents bioclimats.
Endemic genera of the Caucasian flora
Authors: Gagnidze R. , Gviniashvili Ts. , Shetekauri Sh. , Margalitadze N. 
Published: December 2002

AbstractWithin the flora of the Caucasus consists of 17 mono‐ or oligotypic endemic or subendemic genera. Their taxonomy and nomenclature, chorology (latudinal and longitudinal distribution) as well as the site conditions are examined. According to their distribution patterns endemic genera could be classified as follows: Greater Caucasus, Western Caucasus, Central Caucasus, Eastern Caucasus, Greater Eastern Caucasus, and common Caucasus endemics. The centres of diversity of the subendemic genera are in the Caucasus, but spread out into Lazistan and Anatolia, some of them are also found in Iran. Most of the endemic genera developed in the phytogeographical units (phytochorions) of the Colchis and of the Caucasus. The florogenetic relation to Mediterranean genera is demonstrated.The caryogeographic analysis of endemic genera shows that the majority is palaeodiploid. Geographical isolation (with respect to longitude, latitude and altitude) is an important factor in the formation and evolution of the Caucasian flora generated by three‐dimensional landscape structure of the mountains.
Loss of folylpoly‐γ‐glutamate synthetase activity is a dominant mechanism of resistance to polyglutamylation‐dependent novel antifolates in multiple human leukemia sublines
Authors: Liani Esti , Rothem Lilah , Bunni Marlene A. , Smith Clyde A. , Jansen Gerrit , Assaraf Yehuda G. 
Published: December 2002

AbstractWe have studied the molecular basis of drug resistance in human CCRF‐CEM leukemia cells exposed to high dose intermittent pulses of novel polyglutamatable antifolates that target various folate‐dependent enzymes. These include the dihydrofolate reductase (DHFR) inhibitors edatrexate, methotrexate and aminopterin, the thymidylate synthase (TS) inhibitors ZD1694 and GW1843, the glycinamide ribonucleotide formyltransferase (GARTF) inhibitor DDATHF as well as the multitargeted antifolate LY231514 inhibiting both TS, DHFR and GARTF. Fourteen antifolate‐resistant sublines were isolated, 11 of which displayed a drug resistance phenotype that was based on impaired folylpoly‐γ‐glutamate synthetase (FPGS) activity as these cell lines: 1) typically lost 90–99% of parental FPGS activity; 2) expressed 1.4–3.3‐fold less FPGS mRNA (only 4 cell lines); 3) displayed up to 105‐fold resistance to polyglutamylation‐dependent antifolates including ZD1694 and MTA; 4) retained sensitivity to polyglutamylation‐independent antifolates including ZD9331 and PT523; 5) were up to 19‐fold hypersensitive to the lipid‐soluble antifolates trimetrexate and AG377; 6) had a normal or a small decrease in [3H]MTX transport; and 7) had a 2.1–8.3‐fold decreased cellular folate pools and a consequently increased folate growth requirement. The remaining 3 antifolate‐resistant sublines lost 94–97% of parental [3H]MTX transport and thus displayed a high level resistance to all hydrophilic antifolates. To screen for mutations in the hFPGS gene, we devised an RT‐PCR single strand conformational polymorphism (SSCP) assay. RT‐PCR‐SSCP analysis and DNA sequencing showed that only a single FPGS‐deficient subline harbored an FPGS mutation (Cys346Phe). Three‐dimensional modeling of the human FPGS based on the crystal structure of Lactobacillus casei FPGS suggested that this mutation maps to the active site and interferes with the catalytic activity of the enzyme due to a putative bulky clash between the mutant Phe346 and a native Phe350 within α‐helix A10 in a highly conserved C‐terminal hydrophobic core. This was consistent with a 23‐fold decreased affinity of the mutant Cys346Phe FPGS for L‐glutamate. We conclude that decreased FPGS activity is a dominant mechanism of resistance to polyglutamylation‐dependent novel antifolates upon a high‐dose intermittent exposure schedule. The finding that cells may exhibit 5 orders of magnitude of resistance to polyglutamylation‐dependent antifolates but in the same time retain parental sensitivity or hypersensitivity to polyglutamylation‐independent antifolates or lipophilic antifolates offers a potentially promising treatment strategy in the overcoming of FPGS‐based anticancer drug resistance. © 2002 Wiley‐Liss, Inc.
Pharmacokinetic, biochemical and clinical effects of dimethyltriazenoimidazole‐4‐carboxamide–bischloroethylnitrosourea combination therapy in patients with advanced breast cancer
Authors: Clemons Mark , Ranson Malcolm , Margison Jennifer M. , El Teraifi Hassan , Griffiths Audrey , Kelly Jane , Morris Charles Q. , Howell Anthony , Margison Geoffrey P. 
Published: December 2002

AbstractWe assessed whether split dosing with the methylating agent DTIC is an effective strategy for inactivating the DNA repair protein O6‐alkylguanine DNA‐ATase in order to decrease tumour resistance to BCNU. ATase levels in PBMCs were used as a surrogate for tumour ATase depletion to determine whether this correlated with either the pharmacokinetics of DTIC and its major metabolite AIC or other clinical sequelae. Two 1 hr infusions of DTIC (400 mg/m2) 4 hr apart followed another 4 hr later by BCNU (75 mg/m2) were administered every 6 weeks in 7 patients with heavily pretreated advanced breast cancer. The extent and kinetics of ATase depletion and recovery in PBMCs varied not only between patients but also between cycles in the same patient. Serial FNAs showed heterogeneity in tumour ATase expression but no clear pattern of change in ATase activity. DTIC and AIC exhibited biphasic clearance from the blood, consistent with a 2‐compartment pharmacokinetic model. The AUC of AIC was strongly correlated with the percentage decrease in PBMC ATase levels. There were no clinical responses, and toxicity in neutrophils and platelets was marked. Split‐dose DTIC therefore does not appear to be a clinically effective approach to overcome O6‐alkylating agent resistance in advanced breast cancer. © 2002 Wiley‐Liss, Inc.
EphA2 overexpression correlates with poor prognosis in esophageal squamous cell carcinoma
Authors: Miyazaki Tatsuya , Kato Hiroyuki , Fukuchi Minoru , Nakajima Masanobu , Kuwano Hiroyuki 
Published: December 2002

AbstractEphA2 is a member of the Eph family of receptor tyrosine kinases, which interact with cell‐bound ligands known as ephrins. EphA2 expression was investigated by immunohistochemistry with an anti‐EphA2 monoclonal antibody in 80 patients with esophageal squamous cell carcinoma (ESCC) who had undergone surgery. EphA2 overexpression was positive in 40 of the 80 patients (50%). A significant correlation was observed between EphA2 expression and regional lymph node metastasis (p=0.023), number of lymph node metastases (p=0.011) and poor degree of tumor differentiation (p=0.004). The survival rates of EphA2‐positive patients were poorer than those of EphA2‐negative patients (p=0.014). The 5‐year survival rate of patients without EphA2 overexpression was 68%, whereas that of patients with EphA2 overexpression was 29%. EphA2 expression was also investigated in 7 ESCC cell lines (TE‐1, ‐2, ‐8, ‐13, ‐15, TT and TTn) and 1 immortalized human esophageal keratinocyte cell line (CHEK‐1). Western blotting revealed different levels of EphA2 expression in the 8 cell lines. EphA2 was expressed at a high level in the ESCC cell lines compared to CHEK‐1. EphA2 phosphorylation was demonstrated in all cell lines. Northern blot analysis showed that EphA2 mRNA expression in TE‐1 was greater than that in the other ESCC cell lines. The observation of small gaps on Western blot analysis of the ESCC cell lines suggests that there may be a mechanism for EphA2 regulation at the point of translation. In conclusion, EphA2 overexpression appears to be related to poor degree of tumor differentiation and lymph node metastasis in ESCC. Consequently, patients with EphA2 overexpression have a poorer prognosis than those without. EphA2 is a potential target to prevent ESCC cells spreading into the lymphatic drainage. © 2002 Wiley‐Liss, Inc.