Perceptual interactions in two-word displays: Familiarity and similarity effects.

Previous studies have demonstrated the existence of perceptual interactions in the processing of 2-word displays such as SAND LANE. Four experiments were conducted with 99 undergraduates to study the role of familiarity and similarity of the stimuli on these interactions. Exp I examined whether migration errors, and the effect of surround similarity on these errors depend on the fact that the migrating letters fit together with the surround in which they occur to form familiar higher order units. Exp II replicated the results of Exp I using a slightly different paradigm. Exp III examined the role of lexicality, independent of orthographic regularity, by comparing word stimuli to orthographically regular nonword stimuli, and Exp IV examined the role of physical, as opposed to abstract, similarity of the stimuli. Overall findings indicate that when postcued to report 1 of the 2 words, Ss often made migration errors, in that the report of the specified word included a letter of the other word (e.g., LAND or SANE instead of SAND). Migrations depended on the abstract, structural similarity of the strings, but not on the physical similarity; on whether the strings were words; and on whether the possible migration responses were words. Results reveal that migration errors could not be attributed to a guessing strategy. Findings are interpreted in terms of models in which both strings simultaneously access high-level structural knowledge about what sequences of letters fit together to form familiar wholes. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual sensitivity, integral perception, and the similarity classifications of preschool children and adults.

Assessed the developmental role of the salience characteristics of dimensions. In Exp I, 40 children (mean age 4 yrs 5 mo, from upper-middle SES backgrounds were asked to classify compound stimuli according to their similarity. Perceptual sensitivity to the component dimensions of the compounds was varied by means of predisposed and distinctiveness-based salience to determine its effects on the accuracy of similarity classifications. In Exp II, 20 undergraduates completed the same task. Classifications of both the children and adults were more accurate when the salience of the solution-relevant dimension was high than when it was low. Furthermore, sensitization training on a classification-relevant dimension that was initially low in predisposed salience resulted in increasing the subsequent classification accuracy of 4-yr-olds. It was concluded that the similarity classifications of both young children and adults are affected by the salience characteristics of the dimensions of compound stimuli. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of growth and development on cephalometric shapes in orthodontic patients: a Fourier analysis

The age- and gender-related shape variations of the craniofacial skeleton in skeletal Class I children were quantified using a Fourier analysis on the pre-treatment lateral head films of 122 orthodontic patients (age range 7-15 years), who were subdivided into six groups for sex and age (2-year intervals). Seven landmarks representative of the maxillo-mandibular sagittal and vertical relationship were identified and digitized. The contiguous landmarks were connected by segments, the form was normalized with respect to its orientation and size, and a Fourier analysis of the contour was performed. Mean values of the cosine and sine coefficients of the first six harmonics in the sex and age classes were computed. The size-standardized outlines of the oldest boys were narrower and longer than the outlines of the youngest boys (differences at gonion, menton, sella and nasion). Shape differences between mean plots in girls were negligible. In the youngest patients, girls had a larger size-independent shape in the mandibular region; their shape was narrower (anterior-posterior direction) and longer (vertical direction) than male shape. In the oldest patients, boys had a larger size-independent shape at gonion, and a narrower shape at articulare and pogonion than girls. Size increased from the youngest to the oldest boys; size differences were not conspicuous in girls. Within an age class, male size was always larger than female. Fourier analysis allowed a global evaluation of the cephalometric forms, with separate quantifications of the age- and gender-related differences in size and shape.     

Neural feature abstraction from judgments of similarity

The common neural network modeling practice of representing the elements of a task domain in terms of a set of features lacks justification if the features are derived through some form of ad hoc preabstraction. By examining a featural similarity model related to established multidimensional scaling techniques, a neural network is developed that generates features from similarity data and attaches weights to these features. The network performs a constrained search of a continuous solution space to determine the features and uses a previously developed regularization technique to minimize the number of features it derives. The network is demonstrated on artificial data, from which it recovers known features and weights, and on two real data sets involving the similarity of a set of geometric shapes and the abstract conceptual similarities of the 10 Arabic numerals. On the basis of these results, the relationship between the multidimensional scaling approach adopted by the network and an alternative additive clustering approach to feature extraction is discussed.     

QSAR's from similarity matrices. Technique validation and application in the comparison of different similarity evaluation methods

It has recently been shown that good quantitative structure-activity relationships can be obtained through statistical analysis of molecular similarity matrices. Here we extend the technique to seven additional molecular series, previously studied using Comparative Molecular Field Analysis (CoMFA) methodology. The results are used to confirm technique applicability across a wider range of QSAR problems and to compare quantitatively the ability of various similarity indices to describe biological systems. The relative merits of this technique in comparison to CoMFA are discussed.     

铝生产过程中固体废物的处置

叙述了铝生产过程中所产固体废物的种类、性质及处置方法。指出固体废物综合利用是一举多得的措施,符合国家的环境保护政策和可持续发展的战略要求。     

钢铁过程细微颗粒物凝并性能研究

为寻求一种收集钢铁冶炼过程中产生的气溶胶颗粒的方法,研究了EAF粉尘颗粒物的性质.采用Zn蒸汽氧化产生的ZnO模拟气溶胶颗粒进行凝并实验研究,另采用熏香烟雾在不同的搅拌速度下进行气溶胶凝并实验,并将实验结果与理论计算进行比较.同时,采用一种考虑颗粒间相互作用的气溶胶凝并模型估算反应范德华力作用的Hamaker常数.实验结果表明,在搅拌条件下,对于气溶胶的凝并应考虑微细颗粒间的相互作用.     

Purification of scandium from concentrate generated from titanium pigments production waste

Nowadays 80%of scandium in China is obtained from titanium pigments production waste through a complex purification process.The study mainly focused on the purification of Sc from its concentrate generated from titanium pigments production waste by solvent extraction.Several extractants have been tried and 10%D₂EHPA-5%TBP-85%sulfonated kerosene exhibited the best extraction performance towards Sc in 7 mol/L H₂SO₄solution,so it was selected as the oil phase.0.5%of H₂O₂was added into the concentrated solution which can effectively inhibit the extraction of Ti.Both the extraction and back extraction parameters are optimized.The preferred extraction conditions were obtained,i.e.,acidity:7 mol/L H₂SO₄,the phase ratio A/O:10,room temperature,mixed contact time:30 min,Sc concentrate:10 g/L,that the extraction rate of Sc in the above conditions was nearly 100%.NaOH was used for back extraction with the stripping rate 99%on the following conditions:5 mol/L NaOH stripping for 30 min at a phase ratio A/O:1 at 90℃.Finally,H₂C₂O₄was used to further purify the back extraction product and Sc₂(C₂O₄)₃precipitant fo rmed.The final product Sc₂O₃with a purity over 99.5%was obtained by calcining Sc₂(C₂O₄)₃at 1000℃for 2 h.A conceptual process for Sc purification was put forward and proved.The total recovery yield of Sc in the whole process is 95%.     

Perceptual learning of spatiotemporal events: Evidence from an unfamiliar modality.

Perceptual learning was examined in two experiments in which subjects, originally unfamiliar with vibrotactile stimulation, were required to identify dynamic vibrotactile patterns with static visual patterns of the same two-dimensional shapes. In Experiment 1 we examined changes in performance with practice under a variety of vibrotactile spatial and temporal conditions. In Experiment 2 we investigated transfer of learning from one set of vibrotactile patterns to another different set. In neither experiment were subjects supplied with knowledge of results. Substantial perceptual learning (improvement in identification with practice) was observed in Experiment 1, although a minority of subjects did not exhibit improvement. Experiment 2 confirmed the general findings of Experiment 1 and also provided evidence of substantial positive transfer. In both experiments, multidimensional scaling of pattern confusion data revealed that practice (and improvement in identification) did not qualitatively change the relative confusability of patterns, suggesting that the (informative) structure of the patterns, irrespective of familiarity with a specific set of patterns, determined confusability. The findings are interpreted in terms of learning constructs offered by E. J. and J. J. Gibson. We conclude by considering the prospects that a connectionist mechanism can account for the observed perceptual learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arylsulfatase from Klebsiella pneumoniae carries a formylglycine generated from a serine

Eukaryotic sulfatases share an unusual posttranslational protein modification, which converts a cysteine into alpha-formylglycine. The alpha-formylglycine is essential for the catalytic activity. Klebsiella pneumoniae expresses an inducible arylsulfatase for which the DNA predicts a serine at the position occupied by the alpha-formylglycine residue in eukaryotic sulfatases. Structural analysis showed that the majority of the arylsulfatase polypeptides from K. pneumoniae carries the alpha-formylglycine, whereas the remaining arylsulfatase polypeptides contain the predicted serine residue. This demonstrates the evolutionary conservation between prokaryotes and eukaryotes of this novel protein modification that so far has been found only in sulfatases. alpha-Formylglycine in Klebsiella is generated from a serine and not from a cysteine as in eukaryotes.     

Perceptual grouping in space and time: evidence from the Ternus display

Persistence of the brain and kidney Na+,K(+)-ATPase isozymes to SDS inactivation under different time and temperature conditions of microsome extraction with the detergent was compared. In contrast to enzyme preparations from medulla oblongata the higher sensitivity of the Na+,K(+)-ATPase alpha-isoform (in comparison to alpha +) to SDS inactivation accompanied by its, at least, partial removal from the membrane was found in the preparations from cerebral cortex. This difference in the sensitivity to SDS was eliminated after extraction of microsomes with the detergent at 37 degrees C. The interpretation of the results is based on the assumed differences in the structural organization of the boundary lipids of the neuronal Na+,K(+)-ATPase catalytic subunit isoforms.