bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genotype frequencies of the +874T→A single nucleotide polymorphism in the first intron of the interferon‐γ gene in a sample of Sicilian patients affected by tuberculosis
Authors: Lio D. , Marino V. , Serauto A. , Gioia V. , Scola L. , Crivello A. , Forte G. I. , Colonna‐Romano G. , Candore G. , Caruso C. 
Published: March 2003

SummaryIn the light of the key role played by interferon (IFN)‐γ in the control of tuberculosis, in the present paper we have evaluated the distribution of the functional +874T → A IFN‐γ single nucleotide polymorphism (SNP) in Sicilian patients affected by tuberculosis. Our aim was to determine whether there is an association between the TT genotype, which has been suggested to be linked to an increased production of IFN‐γ, and resistance to chronic tuberculosis. DNA samples were obtained from 45 patients and 97 healthy controls. Polymorphism at +874 was identified using amplification refractory mutational system methodology. The +874T SNP was less frequent in patients than in controls (0.42 vs. 0.50) but the difference was not significant. The +874TT genotype, which has been suggested to be associated with high IFN‐γ production, was significantly decreased in the patients. Thus, resistance to chronic lung tuberculosis might be associated with a genetically determined high IFN‐γ production capacity. In conclusion, the present data add another piece of evidence to the complex puzzle of genetic and environmental factors involved in control of infectious diseases. Studies on cytokine gene polymorphisms may elucidate the complex network of trans‐interactive genes influencing the type and strength of responses to environmental stressors and may help to identify the genetic factors that affect survival in humans.
Allelic frequency of the MCP‐1 promoter −2518 polymorphism in the Korean population and in Korean patients with rheumatoid arthritis, systemic lupus erythematosus and adult‐onset Still's disease
Authors: Hwang S.‐Y. , Cho M.‐L. , Park B. , Kim J.‐Y. , Kim Y.‐H. , Min D.‐J. , Min J.‐K. , Kim H.‐Y. 
Published: March 2003

SummaryThe frequency of the monocyte chemoattractant protein‐1 (MCP‐1) −2518 G‐type polymorphism in Koreans is significantly higher than the frequencies reported for Caucasians and Afro‐Americans. The G‐ vs. A‐allele profile in patients with systemic autoimmune diseases is similar to that in healthy Koreans, and does not appear to contribute to elevated MCP‐1 production in patients.
Transformations of phosphorus during incubation of beech leaf litter in the presence of oxides
Authors: MILTNER A. , HAUMAIER L. , ZECH W. 
Published: March 2003

SummarySome minerals have large PO43− sorption capacities. However, we do not know how these mineral phases influence the speciation of organic P when organic matter decomposes. To characterize the interactions between mineral phases and organic P species, we incubated mixtures of beech leaf litter and Fe oxide, Al hydroxide, birnessite, and quartz sand. The samples were extracted with NaOH‐NaF and analysed by 31P nuclear magnetic resonance (NMR) spectroscopy. Phosphate mono‐and diesters gave the most prominent signls in the 31P NMR spectra. During incubation, the proportion of the monoester P decreased, whereas that of the diester P increased. Since NMR intensities assigned to teichoic acids increased, it seems that microbial P accumulated during incubation. The synthesis of microbial compounds was strongest in the presence of Fe oxide. All mineral phases investigated gave rise to a resonance in the 31P NMR spectra which was not present in the control treatment to which the mineral phases had not been added. The resonance was tentatively assigned to sugar diesters, which probably originated from organo‐mineral interactions.
Phosphate‐induced zinc retention in a tropical semi‐arid soil
Authors: AGBENIN J. O. 
Published: March 2003

SummaryZinc (Zn) deficiency symptoms and sporadic responses to applied Zn are being observed frequently in the Nigerian savanna, and one cause is thought to be the growing use of phosphorus (P) fertilizers. This study was designed to test the hypothesis of P‐induced Zn retention in the soils. Soil mixed eith P was incubated at field capacity for 3 weeks at 30 ± 2°C. P levels added to the soil were 0, 500, 1000 and 2000 mg per kg soil. After 3 weeks of incubation, water‐soluble Zn in soil decreased by 92% and exchangeable Zn by 78% with 2000 mg kg−1 of applied P. Zn levels ranging from 0 to 200 mg kg−1 were added to the P‐incubated soil to determine the Zn sorption isotherm and retention capacity. The P‐treated soil retained 93 ± 2% of added Zn compared with 52 ± 2% of the control soil. P treatment changed the Zn sorption isotherm from an L‐curve isotherm to an H‐curve isotherm, indicating strong affinity of P‐treated soil for Zn, probably as a result of the formation of Zn‐phosphate complexes on the soil surface and precipitation at sufficiently large concentrations of P and Zn. At 2000 mg P kg−1, up to 90% of Zn retained by the soil was bound in solid form as ZnHPO4. Varying the soil pH from 3.5 to 9.0, Zn retention by the soil was related to Zn hydrolysis with maximum adsorption occurring at pH 7.3 ± 0.2. The dependence of sorbed Zn on Zn(OH)2° at pH 3.5–7.4 of P‐treated soil indicated that significant van der Waals forces might be involved in Zn retention. The implication of the results of this study for the region is that fertilizer‐P placement around a growing crop plant, commonly practised to maximize fertilizer‐P efficiency, can potentially limit Zn solubility and availability.
General purpose Freundlich isotherms for cadmium, copper and zinc in soils
Authors: Elzinga E. J. , Van Grinsven J. J. M. , Swartjes F. A. 
Published: March 2003

SummaryAssessing the accumulation and transport of trace metals in soils and the associated toxicological risks on a national scale requires generally applicable sorption equations. Therefore Freundlich equations were derived for Cd, Zn and Cu using multiple linear regression on batch sorption data from the literature with a wide variety of soil and experimental characteristics, and metal concentrations ranging over five orders of magnitude. Equations were derived based on both total dissolved metal concentrations and free metal activities in solution. Free metal activities were calculated from total metal concentrations taking into account ionic activity, and inorganic (all metals) and organic complexation (Cu only). Cadmium and Zn were present in solution predominantly as free ions, while Cu was present as organic complexes. Since actual dissolved organic carbon (DOC) concentrations were not available they were estimated using an empirical field relation between DOC and organic matter content. The logarithmic transformation of the Freundlich constant for Cd was regressed on the logarithmic transformations of cation exchange capacity (CEC) (H+) and dissolved Ca, and for Zn with CEC and (H+). For Cu the log–log regression model of the Freundlich constant included the solid:solution ratio of the batch to account for dilution of DOC in the batch as compared with the field. The explained variance for the fitted Freundlich equations was 79% for Cd, 65% for Cu and 83% for Zn, using log‐transformed adsorbed concentrations and soil solution activities. The Freundlich adsorption models underestimated metal contents determined from 1 m HNO3 digestion on field samples, up to a factor of 6 (Cd and Cu) or 10 (Zn).
Measuring bioavailable trace metals by diffusive gradients in thin films (DGT): soil moisture effects on its performance in soils
Authors: Hooda P. S. , Zhang H. , Davison W. , Edwards A. C. 
Published: March 2003

SummaryConventional methods of measuring labile chemical species of trace metals in soil solutions, such as chemical competition following centrifuging, are inadequate if the speciation changes during sampling and extraction. A new technique, diffusive gradients in thin films (DGT), measures labile species of trace metals in natural waters and sediments in situ. A well‐defined diffusive gel layer distinguishes it from other resin‐based techniques. It perturbs the soil in a controlled way by introducing an in situ local sink for metal ions. Resulting fluxes to the device are quantitatively measured, allowing assessment of re‐supply kinetics and in some cases measurement of in situ soil solution concentrations. We used DGT to measure fluxes of Cd, Co, Cu, Ni, Pb and Zn in a sludge‐treated soil at various moisture contents (27–106%). Replicate measurements showed that the precision of DGT‐measured fluxes was within 10%. For moisture contents exceeding the field capacity (42%), the DGT response reflected soil water concentrations. At smaller moisture contents, changes related to tortuosity and dilution were reflected in the measurements. This technique has the potential for in situ measurements in the field where it should provide quantitative flux data on individual soils and provide a good surrogate for bioavailable metal.
Statistics to support soil research and their presentation
Authors: Webster R. 
Published: March 2003

SummaryMuch soil research needs statistics to support and confirm impressions and interpretations of investigations in field and laboratory. Many soil scientists have not been trained in statistical method and as a result apply quite elementary techniques out of context and without understanding.This article concentrates on the most common abuses and misunderstandings and points authors to proper use. It distinguishes variance and standard deviation for measuring dispersion from standard error to indicate confidence in estimates of means. It describes the strictly limited context in which to use the coefficient of variation. It stresses the importance of quoting means and differences between them in contrast to statistical significance, which is at best of secondary interest. It guides readers to inspect and explore their data before deciding to transform them for analysis and illustrates what can be achieved by taking logarithms of single variates and by principal component analysis of multivariate data.
Dissolved organic phosphorus and sulphur as influenced by sorptive interactions with mineral subsoil horizons
Authors: Kaiser K. 
Published: March 2003

SummaryThis study tested the hypothesis that, like dissolved organic nitrogen (N), dissolved organic phosphorus (P) and sulphur (S) are more mobile in soil than is organic carbon (C). To do so, I compared the sorption of organic P and S to subsoil materials with that of organic C. Soil samples were equilibrated with water‐soluble organic matter from the forest floor at pH 4 and in the equilibrium solutions organic C, P, and S, and their distributions between the hydrophilic and hydrophobic fraction were determined. Sorption of C within the organic matter did not differ from that of P and S. However, the hydrophilic fraction contained the vast majority of P and S and sorbed far less than the hydrophobic fraction. So the overall retention of organic P and S was smaller than that of organic C. This result suggested that dissolved organic matter is more important in the loss of plant nutrients than in the release of C from soil.
Heavy metal sorption on soil minerals affected by the siderophore desferrioxamine B: the role of Fe(III) (hydr)oxides and dissolved Fe(III)
Authors: Neubauer U. , Furrer G. , Schulin R. 
Published: March 2003

SummaryPhytoextraction of heavy metals from polluted soils has often been found to be limited by the bioavailability of the pollutants. Inorganic or organic ligands are occasionally used as complexing agents to enhance the mobility of the heavy metals. However, the opposite effect is also possible. We studied the influence of the hydroxamate siderophore desferrioxamine B (DFOB) on the sorption of Cu, Zn and Cd to clay minerals, with the emphasis on the role of dissolved Fe(III) and Fe(III) minerals. Depending on the surface charge of the minerals and on pH, sorption of heavy metals can be either enhanced or diminished. We show here that this effect of DFOB disappears if dissolved Fe(III) is added to suspensions of clay minerals in excess to DFOB. We found that the solid Fe(III) phases ferrihydrite and goethite did not impede the effect of DFOB on the sorption of heavy metal, however. Between pH 4 and 10, DFOB completely prevented Cu sorption on ferrihydrite. A strong mobilizing effect was also observed for Zn, but not for Cd. In presence of goethite, concentrations of dissolved Cu, Zn and Cd were enhanced only above approximately pH 5, 7 and 8, respectively. Below these pH values the binding of these metals to goethite was even stronger with than without DFOB. In the absence of heavy metals, DFOB‐promoted dissolution of ferrihydrite was much faster than that of goethite due to the larger surface area of ferrihydrite. In the alkaline pH range, where sorption of DFOB on the surfaces of the iron oxides was greater, dissolution of both minerals was reduced.
Robust estimation of the pseudo cross‐variogram for cokriging soil properties
Authors: Lark R. M. 
Published: March 2003

SummaryThe pseudo cross‐variogram can be used for cokriging two or more soil properties when few or none of the sampling locations have values recorded for all of them. The usual estimator of the pseudo cross‐variogram is susceptible to the effects of extreme data (outliers). This will lead to overestimation of the error variance of predictions obtained by cokriging. A solution to this problem is to use robust estimators of the pseudo cross‐variogram, and three such estimators are proposed in this paper.The robust estimators were demonstrated on simulated data in the presence of different numbers of outlying data drawn from different contaminating distributions. The robust estimators were less sensitive to the outliers than the non‐robust one, but they had larger variances. Outliers tend to obscure the spatial structure of the cross‐correlation of the simulated variables as described by the non‐robust estimator.The several estimators of the pseudo cross‐variogram were applied to a multitemporal data set on soil water content. Since these were obtained non‐destructively, direct measurements of temporal change can be made. A prediction subset of the data was subsampled as if obtained by destructive analysis and the remainder used for validation. Estimators of the auto‐variogram and pseudo cross‐variogram were applied to the prediction data, then used to predict the change in water content at the validation sites by cokriging. The estimation variances of these predictions were best calculated with a robustly estimated model of coregionalization, although the validation set was too small to conclude that the non‐robust estimators were unsuitable in this instance.
Humus forms in two secondary semi‐evergreen tropical forests
Authors: Loranger G. , Ponge J. F. , Lavelle P. 
Published: March 2003

SummaryThe dynamics and function of humus forms in tropical forests are still poorly understood. Humus profiles in two secondary semi‐evergreen woodlands in Guadeloupe (French West Indies) were analysed micromorphologically. The humus forms are described under the canopy of five dominant tree species at two sites: under Pisonia subcordata and Bursera simaruba in a secondary forest on a Leptosol (Rendzina), and under Swietenia macrophylla, Tabebuia heterophylla and B. simaruba in a plantation on a calcareous Vertisol.In the secondary forest, two distinct humus forms were observed. A calcareous Amphimull, characterized by an OH horizon comprising the faecal pellets of millipedes, is formed under the canopy of P. subcordata, which produces a litter that is rich in nitrogen. A Dysmull with a thick root mat (OFRh horizon) develops under the canopy of B. simaruba, which produces a litter rich in lignin and phenol that is consumed slowly by the soil fauna. In the plantation on the Vertisol, the activity of the endoanecic earthworm Polypheretima elongata has led to the rapid disappearance of litter and the mixing of organic and mineral material. The humus form is a Eumull and is similar under all three tree species present.
Larval fish movement in the River Lohajang,Tangail, Bangladesh
Authors: De Graaf G. J. , Born A. F. , Uddin A. M. K. , Huda S. 
Published: March 2003

AbstractLarval fish drift and distribution patterns were studied in the River Lohajang, a tributary of the River Jamuna, Bangladesh, during the monsoon seasons (June ‐ October) of 1992, 1993 and 1994. Larval fish drift peaks with the water levels of the River Jamuna. In all three years, the Indian carp, Catla catla, Labeo rohita L. and Cirrhinus mrigala, were associated with the first pulses, but were absent from drift samples after September. Hilsa species and other non‐identified fish species were found throughout the monsoon season. The highest larval fish densities were found in the upper strata of the river, near the shore. The drift densities of these fish became evenly distributed through time. Water turbidity probably influenced the vertical and horizontal distribution, and the absence of diel patterns. The most important species in the larval drift were Hilsa spp., followed by Labeo rohita L., Glossogobius giuris L. and Rasbora daniconius. Among the major carp, Labeo rohita was the dominant species, contributing 80‐90%. The impact of flood control programmes on the reproduction of riverine and larval fish drift is discussed.
Influence of invasive macrophytes on channel morphology and hydrology in an open tropical lowland stream, and potential control by riparian shading
Authors: Bunn S. E. , Davies P. M. , Kellaway D. M. , Prosser I. P. 
Published: March 2003

1. The catchments of many tropical lowland streams in far north Queensland have been extensively cleared for the cultivation of sugar cane to the extent where very little of the native riparian vegetation remains. Stream channels are often choked by a matrix of introduced pasture grass (Brachiaria mutica, or para grass) and accumulated sediment from cropland erosion.2. Detailed transects across Bamboo Creek, a fourth order cane‐land stream, revealed an estimated sediment load of 20 000 t km–1. This has resulted in an estimated 85% reduction in the predicted bankful discharge of the original stream channel. Channel capacity has been reduced from 2.3 times to 0.3 times the predicted Q50 flood discharge of 140 m3 s–1.3. Shade cloth treatments of 50% and 90% across the stream were used to mimic the effect of shading by riparian vegetation. Three months of shading resulted in a substantial reduction in the height and standing biomass of para grass in both shade treatments, compared to open plots (0% shade). The most dramatic effect was in the 90% treatment, where a mean reduction of 63% in height and 52% in total biomass was recorded. This was despite high net primary production of para grass in the open plots of 2.8 g dry wt m–2 day–1, which resulted in a overall increase of 11% and 28% in plant height and total biomass, respectively.4. These data suggest that restoration of native riparian vegetation will be an effective long‐term means of controlling invasive macrophytes in disturbed cane‐land stream channels. Reduction of excessive macrophyte growth and the mobilisation of accumulated sediment are essential to the restoration of natural hydrological and ecological processes.
Sublethal parameters in morphologically deformed Chironomus larvae: clues to understanding their bioindicator value
Authors: De Bisthoven L. Janssens , Nuyts P. , Goddeeris B. , Ollevier F. 
Published: March 2003

1. Parameters of condition between normal and deformed fourth instar larvae of

Chironomus

gr.

thummi

(Kieffer 1911) were compared in four populations: one reference (PE) and two metal‐polluted sites (NP and SCH) in the River Dommel, and one site polluted by domestic sewage and copper in the River Ijse (NEI). 2. The site PE ranked lowest for metal body burdens, deformities, mortalities and emergence duration, while SCH and NEI ranked highest. 3. Deformed and non‐deformed larvae most often did not differ in length and weight (

in situ

end‐points for growth); when differences occurred, deformed larvae tended to be smaller. 4. The energy content and dry weights in one population (NEI) were lower in normal larvae than in the weakly deformed ones. The percentage of ash‐free dry weight was lower in deformed larvae of the polluted Dommel sites, compared to the normal ones. 5. The

in vitro

emergence rate (end‐point for development of fourth instars) for the reference population PE, both in its own sediment and in artificial cellulose substrate, was better than for the other sites. In two populations (NEI, SCH) the development of deformed larvae in their own sediment was slower, with higher mortality, than for the normal larvae. In one population (NP), normal and deformed larvae survived and developed equally well. The emergence rates of the respective populations were similarly ranked when the larvae were raised in an artificial cellulose substrate. 6. Elution peaks of alleged metal‐binding proteins were lower in deformed larvae from SCH and NEI, but higher in deformed larvae from NP, than in normal larvae. 7. A different development rate and mortality of deformed larvae in non‐adapted populations and the possibility of metal adaptation, as in site NP, may modulate the final outcome of deformity frequencies, thus having an impact on the biomarker value of deformities in benthic midge larvae.
Aquatic plant diversity in riverine wetlands: the role of connectivity
Authors: Bornette Gudrun , Amoros Claude , Lamouroux Nicolas 
Published: March 2003

1. The hypothesis was tested that intermediate connectivity to a river results in propagule inputs to wetlands, whereas excessive connectivity impedes recruitment, and insufficient connectivity causes less competitive species to be eliminated, with no recruitment of new species. As a consequence, very low or very high nutrient levels should decrease species richness by selecting specialized species, whereas intermediate nutrient levels should favour the co‐occurrence of species with contrasting nutrient requirements.2. Among cut‐off channels with high sinuosity and which are infrequently flooded by the river (low flood scouring), one example possesses high species richness because most species are saved from extinction by long‐term isolation of the channel and cold groundwater supplies. Other channels are poorly supplied with groundwater and show a lower richness of species, because of low propagule inputs and low recruitment potential.3. Cut‐off channels with low sinuosity and which are flooded at intermediate frequencies were divided into three groups. The first group was species‐poor, being closely connected to the river through downstream backflows which maintain nutrient‐rich and turbid waters, in keeping with the hypothesis. The second group presents intermediate richness caused by: (i) lower river backflows; and (ii) floods that partly scour substrate and plants, and afford regeneration niches for transported propagules. The third group was species‐poor because of excessive groundwater supplies, which probably acted as a limiting factor for species growth and recruitment.4. The most frequently flooded channel shows the highest species richness, and occurrence of rare and fugitive species, because of floods which compensate competition by scouring sediments and plants, and afford regeneration niches for propagules. In this case, conservation of biodiversity necessitates propagule sources at the level of the river landscape.