bluuebunny/crossref_metadata_2025_split huggingface dataset:
Group Work in the Efl Classroom in China: A Closer Look
Authors: Chen Runyi , Hird Bernard 
Published: April 2006

Small group work in EFL classrooms has been largely accepted as an effective strategy in the development of students’ communicative proficiency in English. This acceptance has occurred despite a lack of research in key areas about what actually happens when students work in groups in real classrooms.This study examines both quantitative and qualitative data relating to student behaviour in groups collected in EFL lessons in China. Tape recordings of group discussions were analysed and data dealing with turn taking and length of turns were calculated. Interview data were also collected and student perceptions of their contributions to the discussions are presented.Results highlight the complexity of what happens when students work in groups in EFL lessons. The study shows that it is difficult to generalize about student behaviour in group work and though there are some aspects of how students behave in groups that are well understood, there are still many questions that remain unexplored regarding how group work functions in the EFL setting.
Analysis of Methylmalonic Acid in Plasma by Liquid Chromatography–Tandem Mass Spectrometry
Authors: Schmedes Anne , Brandslund Ivan 
Published: April 2006

Abstract
Background: Methylmalonic acid (MMA) is a biochemical marker for cobalamin deficiency, particularly in cases where the cobalamin concentration is moderately decreased or in the low-normal range. Liquid chromatography–tandem mass spectrometry (LC-MS/MS) with electrospray ionization is a rapid, robust method that has been used in MMA analysis. We developed a simple method combining solid-phase extraction (SPE) and derivatization to prepare serum or plasma for LC-MS/MS analysis of MMA.
Methods: Deuterated internal standard d3-MMA was added to serum or plasma before SPE on strong anion-exchange (SAX) columns. After elution with HCl–butanol (10:90 by volume) and addition of 1 g/L formic acid, the samples were simultaneously derivatized and evaporated by heating to 70 °C for 15 min followed by 54 °C overnight in uncapped vials. Acetonitrile and 1 g/L formic acid were added to the samples before injection into the LC-MS/MS system. MMA and d3-MMA were quantified in the multiple-reaction monitoring mode. Calibrators were prepared in serum by the standard addition method.
Results: The MMA assay was linear up to 200 μmol/L. Interassay CVs were 6.7%, 5.0%, and 5.0% for mean concentrations of 0.15, 0.36, and 0.65 μmol/L, respectively.
Conclusions: Our simplified sample preparation and derivatization method is suitable for use in MMA analyses. MMA elutes with the derivatization reagent, and derivatization and evaporation are performed simply by leaving the uncapped vials in a heating block overnight. The method shows good linearity and precision.
Clinical Utility of an Automated Immunochemiluminometric Thyroglobulin Assay in Differentiated Thyroid Carcinoma
Authors: Persoon Adrienne CM , Van Den Ouweland Johannes MW , Wilde Juergen , Kema Ido P , Wolffenbuttel Bruce HR , Links Thera P 
Published: April 2006

Abstract
Background: Thyroglobulin (Tg) measurements are important in the follow-up of patients with differentiated thyroid carcinoma (DTC). We evaluated the analytical and clinical performance of a new automated immunochemiluminometric assay for Tg (Tg-ICMA; Nichols Advantage Tg; Nichols Institute Diagnostics).
Methods: We used the Tg-ICMA to measure Tg concentrations in serum samples from 110 Tg antibody–negative DTC patients undergoing thyroid-hormone suppression therapy. Disease state at the time of measurement was assessed on the basis of routine follow-up data. We compared the clinical performance of this assay with the routinely used IRMA (ELSA-hTG; CIS Bio International).
Results: The detection limit and functional sensitivity of the Tg-ICMA, based on direct calibration to CRM-457, were 0.05 and 0.6 μg/L, respectively. No Tg-IRMA-positive cases were missed by the Tg-ICMA. Tg was measurable by Tg-ICMA (0.6–8.6 μg/L) but undetectable by Tg-IRMA (&lt;1.5 μg/L) in 12 patients (11%). Clinical data showed evidence of disease in 4 of 12 patients (33%).
Conclusions: The Tg-ICMA is a sensitive and reproducible assay for identifying patients in follow-up for DTC with evidence of disease, but uncertainty remains with regard to interpreting findings of measurable serum Tg in patients with no evidence of disease. Follow-up data are required to determine the predictive value of these isolated Tg results. New concepts, i.e., serial Tg measurements and risk stratification of patients, need to be tested to confirm the applicability of this assay for clinical practice.
Multiple-Interval Mapping for Ordinal Traits
Authors: Li Jian , Wang Shengchu , Zeng Zhao-Bang 
Published: April 2006

AbstractMany statistical methods have been developed to map multiple quantitative trait loci (QTL) in experimental cross populations. Among these methods, multiple-interval mapping (MIM) can map QTL with epistasis simultaneously. However, the previous implementation of MIM is for continuously distributed traits. In this study we extend MIM to ordinal traits on the basis of a threshold model. The method inherits the properties and advantages of MIM and can fit a model of multiple QTL effects and epistasis on the underlying liability score. We study a number of statistical issues associated with the method, such as the efficiency and stability of maximization and model selection. We also use computer simulation to study the performance of the method and compare it to other alternative approaches. The method has been implemented in QTL Cartographer to facilitate its general usage for QTL mapping data analysis on binary and ordinal traits.
Cri du Chat Syndrome and Congenital Heart Disease: A Review of Previously Reported Cases and Presentation of an Additional 21 Cases From the Pediatric Cardiac Care Consortium
Authors: Hills Christine , Moller James H. , Finkelstein Marsha , Lohr Jamie , Schimmenti Lisa 
Published: April 2006

OBJECTIVES. To analyze the cases submitted to the Pediatric Cardiac Care Consortium (PCCC) database from 1982 to 2002 to determine the frequency and distribution of congenital heart disease (CHD) found in this population, to review the literature for previously published accounts of CHD in this population, and to review current genotype-phenotype associations for cri du chat (CDC) syndrome with CHD.METHODS. We performed a retrospective review of the 98422 CHD cases submitted to the PCCC between 1982 and 2002, to find patients who had a noncardiac diagnosis of CDC syndrome.RESULTS. A total of 21 patients (15 female and 6 male patients) were identified. Although some patients had multiple cardiac anomalies, they were categorized according to primary diagnoses on the basis of the most hemodynamically significant component. The patient groups were ventricular septal defect (n = 6), patent ductus arteriosus (n = 6), tetralogy of Fallot (n = 5), pulmonary valve atresia with ventricular septal defect (n = 2), pulmonary valve stenosis (n = 1), and double-outlet right ventricle (n = 1). Eighteen of the 21 patients underwent surgical repair of their defects. There was 1 late operative death. To determine whether the observed frequency of these cardiac defects among patients with CDC syndrome was comparable to that of the general population of patients with CHD, data for all cases submitted to the PCCC from 1982 to 2002 were used. Use of these numbers to determine expected frequencies for these defects showed significantly greater proportions of patients with these specific lesions among the patients with CDC syndrome.CONCLUSIONS. Currently there is no clear understanding of the genomic cause of the prevalence of these defects in the population with CDC syndrome, although CHD has been noted among patients with other deletion syndromes.
Rail ballast: conclusions from a historical perspective
Authors: Claisse P. , Calla C. 
Published: April 2006

Although it is now universally accepted that good-quality hard angular stone of nominal size 40–50 mm is the best material for ballast, historically track has been for longer on non-stone ballast than on stone ballast. Even the stone ballast specified up until the 1980s was of a smaller average size than present ballast. Research into the two-layered ballast system and a study of development of ballast specification from the early 1900s suggests that current ballast specifications should be changed to ballast of smaller size. This would: cause substantial reduction in maintenance requirements for ballasted railway track; reduce track noise levels; provide better ride quality; and increase ballast life.
Environmental Impact of Irrigation in La Violada District (Spain)
Authors: Isidoro D. , Quílez D. , Aragüés R. 
Published: April 2006

ABSTRACTSalt loading in irrigation return flows contributes to the salinization of the receiving water bodies, particularly when originated in salt‐affected areas as frequently found in the middle Ebro River basin (Spain). We determined the salt loading in La Violada Gully from the total dissolved solids (TDS) and flows (Q) during the 1995 to 1998 hydrological years. Since this gully collects flows from various sources, an end‐member mixing analysis (EMMA) was performed to quantify the drainage flow from La Violada Irrigation District (VID). Three flow components were identified in La Violada Gully: drainage waters from VID (Qd); tail‐waters from irrigation ditches, spill‐over, and seepage from the Monegros Canal (Qo); and ground water inflows (Qg) originating in the dryland watershed. Gypsum in the soils of VID was the main source for salts in La Violada Gully (flow‐weighted mean TDS = 1720 mg L−1, dominated by sulfate and calcium). The contribution of Qg to the total gully flow during the 1996 irrigation season was low (6.5% of the total flow). The 1995 to 1998 annual salt load average in La Violada Gully was 78 628 Mg, 71% of which was exported during the irrigation season. The 1995 to 1998 irrigation season salt load average in Qd was 43 015 Mg (77% of the total load). Thus, irrigated agriculture in VID was the main source of salt loading in this gully, with a yield of 11.1 Mg of salts per hectare of irrigated land for the irrigation season. Efficient irrigation systems and irrigation management practices that reduce Qd are key factors for controlling off‐site salt pollution of these gypsum‐rich irrigated areas.
Environmental Impact of Irrigation in La Violada District (Spain)
Authors: Isidoro D. , Quílez D. , Aragüés R. 
Published: April 2006

ABSTRACTFertilizer leaching affects farm profitability and contributes to nonpoint‐source pollution of receiving waters. This work aimed to establish nitrate nitrogen export from La Violada Gully in relation to nitrogen fertilization practices in its basin (La Violada Gully watershed, VGW, 19 637 ha) and especially in La Violada Irrigation District (VID, 5282 ha). Nitrogen (N) fertilization in VID (and VGW) was determined through interviews with local farmers for the hydrologic years 1995 and 1996 and NO3‐N load in the gully was monitored from 1995 to 1998. The N fertilizer applied in VGW was 2175 Mg in 1995 and 2795 Mg in 1996. About 43% was applied in VID (945 Mg in 1995 and 1161 Mg in 1996). The most fertilized crop was corn: 398 kg N ha−1(665 Mg) in 1995 and 453 kg N ha−1(911 Mg) in 1996. Nitrogen fertilization was higher than N uptake for irrigated crops, especially for corn and rice. Nitrate N load in La Violada Gully averaged 427.4 Mg yr−1Seventy‐five percent of the exports took place during the irrigation season (321.8 Mg). During the non‐irrigation season maximum NO3‐N loads (3.1 Mg NO3‐N d−1) were found after heavy rains following the N side‐dressing of wheat in the rain‐fed area of VGW (February). During the irrigation season NO3‐N load was determined by outflow from the district (caused by irrigation) and to a lesser extent by changes in NO3concentration (caused by fertilization), showing peaks in April (pre‐sowing corn N fertilization and first irrigations) and June to August (highest irrigation months and corn side‐dress N applications, maximum 6.3 Mg NO3‐N d−1in July). Adjusting N fertilization to crops' needs, improving irrigation efficiencies, and better scheduling N fertilization and irrigation in corn could reduce N export from VID.
Sediment and Phosphorus Transport in Irrigation Furrows
Authors: Bjorneberg D. L. , Westermann D. T. , Aase J. K. , Clemmens A. J. , Strelkoff T. S. 
Published: April 2006

ABSTRACTSediment and phosphorus (P) in agricultural runoff can impair water quality in streams, lakes, and rivers. We studied the factors affecting P transfer and transport in irrigated furrows in six freshly tilled fallow fields, 110 to 180 m long with 0.007 to 0.012 m m−1 slopes without the interference of raindrops or sheet flow that occur during natural or simulated rain. The soil on all fields was Portneuf silt loam (coarse‐silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids). Flow rate, sediment concentration, and P concentrations were monitored at four, equally spaced locations in each furrow. Flow rate decreased with distance down the furrow as water infiltrated. Sediment concentration varied with distance and time with no set pattern. Total P concentrations related directly to sediment concentrations (r2 = 0.75) because typically >90% of the transported P was particulate P, emphasizing the need to control erosion to reduce P loss. Dissolved reactive phosphorus (DRP) concentrations decreased with time at a specific furrow site but increased with distance down the furrow as contact time with soil and suspended sediment increased. The DRP concentration correlated better with sediment concentration than extractable furrow soil P concentration. However, suspended sediment concentration tended to not affect DRP concentration later in the irrigation (>2 h). These results indicate that the effects of soil P can be overshadowed by differences in flow hydraulics, suspended sediment loads, and non‐equilibrium conditions.
SignificantEscherichia coliAttenuation by Vegetative Buffers on Annual Grasslands
Authors: Tate Kenneth W. , Atwill Edward R. , Bartolome James W. , Nader Glenn 
Published: April 2006

ABSTRACTA study was conducted to estimate the retention efficiency of vegetative buffers forEscherichia colideposited on grasslands in cattle fecal deposits and subject to natural rainfall‐runoff conditions. The study was conducted on annual grasslands in California's northern Sierra Nevada foothills, a region with a distinct wet–dry season Mediterranean climate. We used 48, 2.0‐ by 3.0‐m runoff plots to examine the efficacy of 0.1‐, 1.1‐, and 2.1‐m buffers at three land slopes (5, 20, and 35%) and four dry vegetation matter levels (225, 560, 900, and 4500 kg/ha) across 27 rainfall‐runoff events during two rainfall seasons. Buffer width treatments were implemented by placement of cattle fecal material containing known loads ofE. coli0.1, 1.1, or 2.1 m upslope of the plot runoff collector. Mean total runoff to total rainfall ratio per plot ranged from 0.014:1 to 0.019:1 and reflected the high infiltration capacity of these soils. Approximately 94.8 to 99.995% of totalE. coliload applied to each plot appears to be either retained in the fecal pat and/or attenuated within 0.1 m downslope of the fecal pat, irrespective of the presence of a wider vegetated buffer. Relative to a 0.1‐m buffer, we found 0.3 to 3.1 log10reduction inE. colidischarge per additional meter of vegetative buffer across the range of residual dry vegetation matter levels, land slope, and rainfall and runoff conditions experienced during this project. Buffer efficiency was significantly reduced as runoff increased. These results support the assertion that grassland buffers are an effective method for reducing animal agricultural inputs of waterborneE. coliinto surface waters.
Peat Fire Effects on Some Properties of an Artificially Drained Peatland
Authors: Dikici Huseyin , Yilmaz C. Hakan 
Published: April 2006

ABSTRACTThe management of artificially drained organic soils is a very important issue, since the accelerated mineralization and sometimes peat fires alter physical and chemical properties of soils and the availability of plant nutrients. This study was performed to determine relatively short‐ and long‐term effects of peat fires on some physical and chemical properties of soils in the artificially drained Gavur Lake Peatland of Turkey. To achieve this objective, measured properties of soils burned in 2001, burned in 1965, and unburned were compared. The results indicated that soil bulk density, pH, amounts of soluble salts, CaCO3, and concentrations of ammonium acetate–extractable (AAE) Ca, Mg, K, and Na were significantly higher for both sampling depths in the burned areas. The areas burned in 2001 had higher pH, soluble salts, and the concentrations of AAE Ca, Mg, and K compared with sites burned in 1965, and this was reasoned with leaching losses and plant uptake of these basic cations for four decades in the latter. Percent saturation and organic carbon contents of soils, however, were significantly lower in the burned areas for both sampling depths. Olsen P levels were not significantly different between the sites. This work clearly shows that alterations in soils properties with peat fires do not recover in the long term.
Behavior of an Aerated Submerged Fixed‐Film Reactor (ASFFR) under Simultaneous Organic and Ammonium Loading
Authors: Nabizadeh R. , Mesdaghinia A. 
Published: April 2006

ABSTRACTThe performance of an aerated submerged fixed‐film reactor (ASFFR) under simultaneous organic and ammonium loading and its effect on nitrification was studied. Organic loadings varied in the range of 1.93 to 5.29 g chemical oxygen demand (COD) m−2 d−1 and NH4–N loadings were in the range of 116 to 318 mg NH4–N m−2 d−1 Increments of loading rates were obtained both by increasing the flow rate and increasing the influent substrate in individual pilot runs. Results showed that with organic loading rates up to 3.97 g COD m−2 d−1, complete nitrification was achievable. Although high organic loading such as 5.29 g COD m−2 d−1 could cause nitrification to stop, shifting to lower organic loadings made nitrification start and set rapidly to its previous steady‐state concentrations. Comparison of results showed that in the ASFFR, nitrification would be severely affected by an organic loading rate of 5.29 g COD m−2 d−1 by increasing either the flow or the influent substrate. It should be noted that the average value of dissolved oxygen was 3.4 mg L−1 with an air supply of 15 L min−1, and there was no indication of oxygen limitation. The results of this study show the flexibility of ASFFRs under changing organic loads. Furthermore, for achieving complete nitrification and optimum application of these reactors for protecting receiving water from the environmental hazards of ammonium, the maximum organic loading that would present complete nitrification should be considered.
Lead Transport into Bayou Trepagnier Wetlands in Louisiana, USA
Authors: Devall Margaret S. , Thien Leonard B. , Ellgaard Erik , Flowers George 
Published: April 2006

ABSTRACTEstablishment of a petroleum refinery in 1916 near the headwaters of Bayou Trepagnier with subsequent dredging of the bayou resulted in spoil banks containing high levels of Pb. A large swamp abuts the eastern bank of the bayou. Cores were taken from 15 baldcypress [Taxodium distichum(L.) Richard] trees growing in the swamp along a 610‐m transect (nine trees) and a 183‐m transect (six trees) running perpendicular from the spoil bank. The cores were crossdated, annual rings were measured, and 5‐yr segments of the cores were prepared and analyzed for heavy metals. Soil samples were collected along one transect and analyzed for metals. Levels of Pb in Bayou Trepagnier swamp trees were compared to levels in nine baldcypress trees growing along Stinking Bayou, a reference area. During the last 100 yr, Pb in growth rings of swamp baldcypress trees averaged 8.6 mg/kg (SD 4.88) along one transect and 7.9 mg/kg (SD 5.39) along the other. Lead in the soil along the first transect dropped from >2700 mg/kg (spoil bank) to 10 mg/kg at 420 m into the swamp. Baldcypress trees growing near the refinery on the spoil bank along Bayou Trepagnier (covered in an earlier study) averaged 4.5 mg/kg Pb, and trees along Stinking Bayou averaged 2.1 mg/kg. Trees in the swamp soil with 10 to 425 mg/kg Pb concentrated much more Pb than trees growing on the heavily polluted bank. Greater uptake of Pb by trees in the swamp is discussed in terms of soil dynamics and Pb sources.
Measuring Runoff‐Suspended Solids Using an Improved Turbidometer Method
Authors: Ginting Daniel , Mamo Martha 
Published: April 2006

ABSTRACTDifferences in particle size distribution between runoff standards and unknown samples affect the accuracy of estimation of total suspended solids (TSS) concentration using the nephelometric turbidity (NTU) method. The objective was to quantify the effects of a sucrose solution as suspending medium and contrasting particle size distribution on nephelometric turbidity and accuracy of TSS estimation. Nineteen benchmark soils varying in texture and color were divided into particle size distribution of <250 and <2000 μm. Soils from these two aggregate classes were then made into suspension ranging from 0.2 to 15 g L−1 using distilled deionized water. Runoff suspensions ranging from 0.2 to 21 g L−1 were also collected from different watersheds. Turbidity of soil and runoff suspensions was measured in sucrose solution and in distilled deionized water. The sucrose solution density ranged from 1.10 to 1.30 kg L−1 Increasing sucrose solution density decreased turbidity. The TSS concentration was most sensitive to changes in turbidity with the 1.30 kg L−1 sucrose solution. Using the 1.30 kg L−1 sucrose solution, particle size bias and error of TSS estimates were decreased by at least 20% compared to distilled deionized water. Reduction in refraction index differences between the suspended particles and sucrose solution combined with reduced particle settling and reduced Brownian motion resulted in dampening the effects of particle size distribution. We propose a sucrose solution of 1.30 kg L−1 as a better suspending medium to dampen the effect of particle size distribution and thus improve suspension TSS concentration estimation.