Passive optical separation and enrichment of cells by size difference

A size-selective cell sorting microfluidic device that utilizes optical force is developed. The device consists of a three-dimensional polydimethylsiloxane microstructure comprised of two crossed microchannels in a three-dimensional configuration. A line shaped focused laser beam is used for automatic size-selective cell sorting in a continuous flow environment. As yeast cells in an aqueous medium are fed continuously into a lower channel, the line shaped focused laser beam is applied (perpendicular to the direction of flow) at the junction of the two crossed channels. The scattering force of the laser beam was employed to push cells matching specific criteria upward from one channel to another. The force depends on the size of the cells, the laser power, and the fluid flow speed. The variation in size of yeast cells causes them to follow different routes at the intersection. For flow speeds below 30 μm∕s, all yeast cells larger than 3 μm were removed from the main stream. As a result, a high purity sample of small cells can be collected at the outlet of bottom channel.     

Automatization aspects of dyslexia: speed limitations in word identification, sensitivity to increasing task demands, and orthographic compensation

A study is presented in which three characteristics of dyslexia were examined: (a) speed limitations in word identification, (b) sensitivity to increasing task demands, and (c) orthographic compensation. Ten students with dyslexia (10 years old) were compared to 10 chronological-age controls and 20 reading-age controls on their performance in reading. Response latencies of the students with dyslexia were slower when familiar words, letter clusters, and nonwords had to be named. A larger word-frequency effect and a larger word-length effect in the these students indicates that they have difficulty with increasing task demands. In addition, a subword-frequency effect was found to be larger in the students with dyslexia. These differences among the three groups of students are interpreted in terms of automatization. Furthermore, it is suggested that students with dyslexia may have a preference for large orthographic units, which is used as a compensatory tool in reading.     

植物园和植物资源的保护

植物园有引进和改良植物的长期历史,对粮食、香料、树木和种植作物的开发起了重要作用。植物园对数万种植物进行了引种栽培,是自然界之外保存最大量植物多样性的场所。近来,植物园主要致力于保护,有时也进行再引进野生植物种,特别着重于那些珍稀或濒危品种。     

More power to them--statistically, that is: a commentary on Studdert-Kennedy, Mody, and Brady's criticism of a critique

The power analysis discussed above establishes that it was most unlikely that Mody et al. (1997) could make a meaningful test of the Tallal hypothesis because of inadequate n and failure to specify the effect size. Note that this is a best-case scenario, because the power analysis assumes that the analysis of variance assumptions were within reasonable boundaries (e.g., as specified by Norton's study). This was clearly not the case. In summary, the Mody et al. study fails to meet minimal scientific criteria and makes no meaningful contribution to the literature.     

ADHD and reading disabilities: a cluster analytic approach for distinguishing subgroups

Data suggest that children with reading disability (RD) and non-RD children with attention-deficit/hyperactivity disorder (ADHD) may comprise distinct subgroups. Research has been hampered by variance in definitional criteria, which results in the study of different subgroups of children. Using cluster analysis, this study empirically divided children with ADHD (N = 54), based on their Full Scale IQ (FSIQ) and reading ability. Four distinct subgroups emerged in which cognitive, behavioral, and neurochemical function was compared. Cluster 1 was of average FSIQ and reading scores; Cluster 2 was of average FSIQ but showed impairment in reading; Cluster 3 had high FSIQ and reading scores; and Cluster 4 had low scores in both domains. The groups had different patterns of cognitive, behavioral, and neurochemical function, as determined by discrepancies in Verbal-Performance IQ, academic achievement scores, parent aggression ratings, and a measure of noradrenergic function. These distinctions are discussed with regard to etiology, treatment, and long-term outcome.     

Do young children always say yes to yes-no questions? A metadevelopmental study of the affirmation bias

The present study investigated whether yes-no questions would lead to a yes bias in young children. Four experiments were conducted in which 2- to 5-year-olds were asked comprehensible and incomprehensible yes-no questions concerning familiar and unfamiliar objects. Consistent findings were obtained: (a) 2-year-olds displayed a consistent yes bias; (b) 4- and 5-year-olds exhibited no response bias toward comprehensible questions and a nay-saying bias toward incomprehensible questions; and (c) 3-year-olds' results were mixed, suggesting that the age of 3 years is a period of developmental transition in response tendency toward yes-no questions. The findings suggest that yes-no questions are suitable for older children, providing they are comprehensible, but may result in biased results when used with younger children and when incomprehensible.     

Effects of outpatient treatment of dyslexia

The effects of a Dutch intervention program for dyslexia are reported. The program was individually tailored, depending on the style of reading, the phase of the learning process, and the intermediate results of the treatment. Two groups of participants were involved: (a) a group of children with pure dyslexia (n = 109) and (b) a group that had reading problems but also suffered from cognitive deficits or psychiatric symptoms (n = 29). Scores of reading single words and text at intake and after the intervention were analyzed to assess the efficacy of the intervention program. Furthermore, the effects of pre-intervention variables such as intelligence, reported speech, and language problems and of intervention variables such as the initial level of performance and the duration of the treatment were examined. Both groups benefitted from the intervention, but the children with pure dyslexia profited most. Neither of the groups could catch up the reading deficit. Intelligence and reported speech and language problems did not affect the treatment outcomes. Individual differences in treatment outcome were related to the absolute level of word reading and age at intake. In the group with comorbidity, the intervention program was more successful in relatively younger children. Within this group, the cognitive deficits and types of psychiatric problems were not related to the treatment.     

Effects of replica running shoes upon external forces and muscle activity during running

Twelve participants ran (9 km · h(-1)) to test two types of running shoes: replica and original shoes. Ground reaction force, plantar pressure and electromyographic activity were recorded. The shoes were tested randomly and on different days. Comparisons between the two experimental conditions were made by analysis of variance (ANOVA) test (P ≤ 0.05). The time to first peak, loading rate of the first peak and impulse of the first 75 ms of stance were significantly different between the shoes (P ≤ 0.05), revealing an increase of impact forces for the replica shoes. The peak plantar pressure values were significantly higher (P ≤ 0.05) when wearing replica shoes. During running, the contact area was significantly smaller (P ≤ 0.05) for the replica shoe. The electromyographic activity of the analysed muscles did not show changes between the two shoes in running. These findings suggest that the use of replica running shoes can increase the external load applied to the human body, but may not change the muscle activity pattern during locomotion. This new mechanical situation may increase the risk of injuries in these movements.