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23.
A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate (SSP), phosphate rock (PR), and calcium magnesium phosphate (CMP) significantly decreased the percentage of water-soluble and exchangeable (WE) soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control (CK). The results showed that the level of 300 g P/mE soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil decreased by three phosphorus fertilizers followed the order: CMP (79%)〉SSP (41%)〉PR (23%); Effectiveness on the reduction of Pb uptake by cabbage was in the order: CMP (53%)〉SSP (41%)〉PR (30%). Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment. 相似文献
24.
Langdown BL Bridge M Li FX 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(2):273-287
Traditionally, golf biomechanics has focused upon achieving consistency in swing kinematics and kinetics, whilst variability was considered to be noise and dysfunctional. There has been a growing argument that variability is an intrinsic aspect of skilled motor performance and plays a functional role. Two types of variability are described: 'strategic shot selection' and 'movement variability'. In 'strategic shot selection', the outcome remains consistent, but the swing kinematics/kinetics (resulting in the desired ball flight) are free to vary; 'movement variability' is the changes in swing kinematics and kinetics from trial to trial when the golfer attempts to hit the same shot. These changes will emerge due to constraints of the golfer's body, the environment, and the task. Biomechanical research has focused upon aspects of technique such as elite versus non-elite kinematics, kinetics, kinematic sequencing, peak angular velocities of body segments, wrist function, ground reaction forces, and electromyography, mainly in the search for greater distance and clubhead velocity. To date very little is known about the impact of variability on this complex motor skill, and it has yet to be fully researched to determine where the trade-off between functional and detrimental variability lies when in pursuit of enhanced performance outcomes. 相似文献
25.
Pathways to mathematics: longitudinal predictors of performance 总被引:1,自引:0,他引:1
LeFevre JA Fast L Skwarchuk SL Smith-Chant BL Bisanz J Kamawar D Penner-Wilger M 《Child development》2010,81(6):1753-1767
A model of the relations among cognitive precursors, early numeracy skill, and mathematical outcomes was tested for 182 children from 4.5 to 7.5 years of age. The model integrates research from neuroimaging, clinical populations, and normal development in children and adults. It includes 3 precursor pathways: quantitative, linguistic, and spatial attention. These pathways (a) contributed independently to early numeracy skills during preschool and kindergarten and (b) related differentially to performance on a variety of mathematical outcomes 2 years later. The success of the model in accounting for performance highlights the need to understand the fundamental underlying skills that contribute to diverse forms of mathematical competence. 相似文献
28.
The School of Medicine at the Medical College of Virginia Campus of Virginia Commonwealth University examined the 2005/2006 medical school curriculum to ensure that students were prepared to meet the informatics objectives put forward by the AAMC Medical School Objectives Project published in 1998. The AAMC Medical Informatics Objectives Survey, issued in 2005, led the VCU School of Medicine to investigate the points of integration between informatics objectives and course syllabi for the first three years of the medical school curriculum. This analysis raised awareness of the informatics objectives with SOM faculty and staff and showed that more than 74% of the informatics objectives have been integrated into the curriculum. 相似文献
29.
Xie JK Kong XL Chen J Hu BL Wen P Zhuang JY Bao JS 《Journal of Zhejiang University. Science. B》2011,12(7):518-526
Rice straw is always regarded as a by-product of rice production, but it could be a significant energy source for ruminant
animals. Knowledge of the genetic variation and genetic architecture of cell wall traits will facilitate rice breeders by
improving relevant traits through selective breeding and genetic engineering. The common wild rice, Oryza rufipogon Griff., which is considered to be the progenitor of Oryza sativa, has been widely utilized for the identification of genes of agronomic importance for rice genetic improvement. In the present
study, the mapping of quantitative trait loci (QTLs) for acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent
lignin (ADL), and ADL/NDF ratio was carried out in two environments using a backcrossed inbred line (BIL) population derived
from a cross between the recurrent parent Xieqingzao B (XB) and an accession of Dongxiang wild rice (DWR). The results indicated
that all four traits tested were continuously distributed among the BILs, but many BILs showed transgressive segregation.
A total of 16 QTLs were identified for the four traits, but no QTLs were in common in two environments, suggesting that environment
has dramatic effects on fiber and lignin syntheses. Compared to the QTL positions for grain yield-related traits, there were
no unfavorable correlations between grain yield components and cell wall traits in this population. The QTLs identified in
this study are useful for the development of dual-purpose rice varieties that are high in grain yield and are also high in
straw quality. 相似文献
30.
To investigate social exclusion, 146 dyads of close friends (N = 292, ages 10, 12, and 14) were observed as they played a board game with a same-gender confederate actor, trained to be a difficult play partner. Verbalizations and gestures were coded for verbal and nonverbal social exclusion, verbal aggression, and verbal assertion. The results indicated few developmental differences. For verbal responses in the presence of the actor, boys were more socially exclusive and verbally aggressive than were girls. Girls engaged in more nonverbal social exclusion in the presence of the actor than did boys. Girls' socially exclusive behaviors were unrelated to other negative behaviors and more strongly related between friends in the actor's absence. 相似文献