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21.
The effects of identical context on pattern recognition by pigeons for outline drawings of faces were investigated by training pigeons to identify (Experiment 1) and categorize (Experiment 2) these stimuli according to the orientation of the mouth—an upright U shape representing a smiling mouth or an inverted U shape representing a sad mouth. These target stimuli were presented alone (Pair 1), with three dots in a triangular orientation to represent a nose and eyes (Pair 2), and with the face pattern surrounded by an oval (Pair 3). In Experiment 1, the pigeons trained with Pair 1 were most accurate, those trained with Pair 2 were less so, and those trained with Pair 3 failed to acquire the discrimination within eighty 100-trial sessions. The same ordering was found in Experiment 2 for pigeons trained on the three pairs simultaneously. The authors suggest that a contrasting finding in humans, the face superiority effect, might be due to a gain in discriminability resulting from recognition of the pattern as a face. An exemplar model of information processing that excludes linguistic coding accounts for the present results.  相似文献   
22.
织物风格特征是由织物组织结构和纱的特性决定的,新型纱线结构的不断出现和发展对织物性能和质量提出了更高的要求。研究表明:通过改变纺纱工艺可以获得不同的纱线结构,从而改变织物的风格特征。DREF-Ⅲ型摩擦纺包芯纱具有典型的皮芯结构,可以是双组分也可以是多组分,而且组分的不同会对织物性能产生不同的影响,纱的性能也会由于芯皮之间压力、摩擦力大小的不同而改变。以前的研究主要集中在包芯纱的拉伸性能上,而对空心纱几乎没有什么新的研究和讨论。  相似文献   
23.
OBJECTIVES: To investigate whether an information literacy programme for pre-registration nursing students at a UK higher education institution is effective in developing their skills and confidence: examines students' skill levels, factors affecting their confidence, and relationships between skills, confidence and demographic characteristics. METHODS: Quantitative and qualitative techniques were used: pre- and post-tests to measure changes in students' skills and self-assessed confidence levels after two key sessions in their first semester (n = 29); semi-structured interviews to explore factors affecting confidence (n = 5). RESULTS: Findings demonstrated positive impacts on skills and confidence. Key areas of skill development included: identifying journal articles, selecting search terms and evaluating website quality. Factors affecting confidence included: successful 'mastery' experiences in searching for information and the programme itself, especially small-group sessions, handouts and staff support. Evidence on links between skills, confidence and demographic factors was inconclusive. CONCLUSIONS: The study demonstrated the programme's effectiveness and identified areas for development, including the need to help students understand the relative merits of search engines and other sources. Evidence has contributed to a change in departmental policy, making attendance at sessions mandatory. Further studies have been recommended.  相似文献   
24.
Objective: To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods: A series of twenty-six compounds of N^4-(4-bromo-3-methylphenyl) semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine (scSTY) and subcutaneous picrotoxin (scPIC) seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS (central nervous system) depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results: Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels was, the greater was the activity profile. Conclusion: The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds.  相似文献   
25.
The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for fruit shape traits (fruit length and fruit perimeter) in sponge gourd was conducted by employing a developmental genetic model including fruit direct effects and maternal effects. Analysis approaches of unconditional and conditional variances were applied to evaluate the genetic behavior of fruit shape traits at economical and physiological maturation times. The results of variance analysis indicated that fruit length and fruit perimeter were simultaneously affected by fruit direct genetic effects and maternal effects. Fruit direct genetic effects were relatively more important for fruit shape traits at whole developmental period. The gene expression was most active at the economical maturation stage (1-12 d after flowering) for two shape traits, and the activation of gene was mostly due to direct dominance effects at physiological maturation stage (13-60 datter flowering). The coefficients due to different genetic effects, as well as the phenotypic correlation coefficients, varied significantly between fruit shape traits themselves at various maturation stages. The results showed that it was relatively easy to improve fruit shape traits for industrial purpose by carefully selecting the parents at economical maturation stage instead of that at physiological maturation stage.  相似文献   
26.
In an effort to provide high-quality preschool education, policymakers are increasingly requiring public preschool teachers to have at least a Bachelor's degree, preferably in early childhood education. Seven major studies of early care and education were used to predict classroom quality and children's academic outcomes from the educational attainment and major of teachers of 4-year-olds. The findings indicate largely null or contradictory associations, indicating that policies focused solely on increasing teachers' education will not suffice for improving classroom quality or maximizing children's academic gains. Instead, raising the effectiveness of early childhood education likely will require a broad range of professional development activities and supports targeted toward teachers' interactions with children.  相似文献   
27.
Shtulman A  Carey S 《Child development》2007,78(3):1015-1032
The present study investigated the development of possibility-judgment strategies between the ages of 4 and 8. In Experiment 1, 48 children and 16 adults were asked whether a variety of extraordinary events could or could not occur in real life. Although children of all ages denied the possibility of events that adults also judged impossible, children frequently denied the possibility of events that adults judged improbable but not impossible. Three additional experiments varied the manner in which possibility judgments were elicited and confirmed the robustness of preschoolers' tendency to judge improbable events impossible. Overall, it is argued that children initially mistake their inability to imagine circumstances that would allow an event to occur for evidence that no such circumstances exist.  相似文献   
28.
The aims of this study were (a) to determine whether Spanish children with reading disabilities (RD) show a speech perception deficit and (b) to explore the locus and nature of this perceptive deficit. A group of 29 children with RD, 41 chronological age-matched controls, and 27 reading ability-matched younger controls were tested on tasks of speech perception. The effect of linguistic unit (word vs. syllable) and type of phonetic contrast (voicing, place and manner of articulation) were analyzed in terms of the number of errors and the response time. The results revealed a speech perception deficit in Spanish children with RD that was independent of the type of phonetic contrast and of linguistic unit.  相似文献   
29.
OBJECTIVES: The study was designed to explore whether the credibility of children's statements regarding their alleged experiences of child sexual abuse could be assessed in a more valid and reliable way when investigative interviews were conducted using the NICHD protocol rather than in an unstructured manner. METHODS: Forty-two experienced Israeli youth investigators each assessed the credibility of allegations of sexual abuse made by alleged victims of sexual abuse when interviewed either with or without the protocol. Half of the alleged incidents were judged likely to have happened ("plausible") on the basis of independent evidence, while half were deemed unlikely to have happened ("implausible"). RESULTS: More non-protocol than protocol interviews were rated as "No judgment possible" rather than either credible or incredible. Allegations made in protocol interviews were more accurately rated as credible or incredible when they were either plausible or implausible, respectively, than those made in non-protocol statements. Levels of inter-rater reliability were also higher when protocol interviews were rated. The differences were significant only for plausible cases, however. CONCLUSIONS: The use of the NICHD protocol facilitated the assessment of credibility by child investigators although incredible allegations (those describing incidents that were unlikely to have happened) remained difficult to detect, even when the protocol was used.  相似文献   
30.
在太阳能实际应用中,较低的光伏转换效率是主要技术瓶颈。本项目围绕如何直接改进太阳能电池板的面形结构和特性,实现一种更加简捷有效的提高光伏转换效率的技术途径。借助照相机在镜头中采用凸透镜和镀增透膜来增加聚光性能的思想,本方案采用玻璃微珠所具备的短焦距聚光能力增大太阳光的接收角,同时选用溶胶凝胶膜层增加光线透过性。实验验证了玻璃微珠和溶胶凝胶膜层对提高光伏转换效率的科学可行性。实验结果表明,在宽光谱卤素灯大角度(70°)入射条件下,光伏转换效率相对玻璃基板提高了15.73%,充分验证了设计方案的原理可行性。本方法主要基于对太阳能电池玻璃盖板的结构改进,不需额外增加光学系统,结构简单,易于实现,设计思想具有独立创新性,在提高太阳能的光伏转换效率方面有着重要应用价值和发展前景。  相似文献   
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