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181.
    
In this article, we propose an efficient atomic packing cluster-based composition protocol to help design Al-based metallic glasses. Its validity is verified by some typical experimental data from the literatures. Furthermore, with this understanding, the Al–Ni–Y alloy system is re-evaluated. As a result, the best glass former Al86Ni9Y5 in this system, with the critical thickness of about 500 µm, is successfully fabricated by wedge casting.  相似文献   
182.
A dominant Goss texture component instead of a Brass texture component has been observed in a warm-rolled Fe–28Mn–6Si–5Cr shape memory alloy [H. Li, F. Yin, T. Sawaguchi K. Ogawa, X. Zhao and K. Tsuzaki, Mater. Sci. Eng. A 494 (2008) p.217]. In order to clarify the orientation flow mechanism in these grains of Goss orientation, investigations on microtexture and microstructure were carried out by electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). It is concluded that the Goss–Brass orientation transformation is restrained in the Goss-orientated grains, which were widely observed in both the deformed matrix and shear bands.  相似文献   
183.
The most common genetic contributor to late-onset Parkinson disease (PD) is the LRRK2 gene. In order to effectively integrate LRRK2 genetic testing into clinical practice, a strategy tailored to the PD population must be developed. We assessed 168 individuals with PD for baseline knowledge of genetics, perceived risk, and interest and opinions regarding genetic counseling and testing. Most participants felt that they were familiar with general genetics terms but overall knowledge levels were low, with an average score of 55%. The majority of participants thought it was likely they inherited a PD gene (72%), believed genetic testing for PD would be useful (86%), and were interested in genetic testing (59%) and genetic counseling (56%). However, only a few participants had heard of any genetic tests for PD (29%) or LRRK2 (10%). There appears to be a significant level of interest in genetics and genetic testing within the PD population, but a considerable deficit in genetics knowledge and an over-estimation of risk. Genetic education and counseling tools to address these needs were developed to provide patients with the ability to make informed and knowledgeable genetic testing decisions.  相似文献   
184.
目前医德教育在教育时间与教育手段等方面缺乏延续性。通过对医德教育的特点和规律以及传统医德教育存在的弊病、医疗领域不正之风的负面影响等问题的分析,提出应着手构建在校医学生—实习生—在职医务人员"三位一体"的"延续性医德教育"模式,实现"第一课堂与第二课堂"、"系统医德理论与实践"、"被动性与自主性"医德教育三结合。  相似文献   
185.
Manual discrimination of force using active finger motion.   总被引:5,自引:0,他引:5  
In these experiments, two plates were grasped between the thumb and forefinger and squeezed together along a linear track. An electromechanical system presented a constant resistance force during the squeeze up to a predetermined location on the track, whereupon the force effectively went to infinity (simulating a wall) or to zero (simulating a cliff). The task of the subject was to discriminate between two alternative levels of the constant resistance force (a reference level and a reference-plus-increment level). Results of these experiments indicate a just noticeable difference of roughly 7% of the reference force using a one-interval paradigm with trial-by-trial feedback over the ranges 2.5 less than or equal to F0 less than or equal to 10.0 newtons, 5 less than or equal to D less than or equal to 30 mm, 45 less than or equal to S less than or equal to 125 mm, and 25 less than or equal to V less than or equal to 160 mm/sec, where F0 is the reference force, D is the distance squeezed, S is the initial fingerspan, and V is the mean velocity of the squeeze. These results, based on tests with 5 subjects, are consistent with a wide range of previous results, some of which are associated with other body surfaces and muscle systems and many of which were obtained with different psychophysical methods.  相似文献   
186.
The anchoring of lightness perception was tested in simple visual fields composed of only two regions by placing observes inside opaque acrylic hemispheres. Both side-by-side and center/surround configurations were tested. The results, which undermine Gilchrist and Bonato's (1995) recent claim that surrounds tend to appear white, indicate that anchoring involves both relative luminance and relative area. As long as the area of the darker region is equal to or smaller than the area of the lighter region, relative area plays no role in anchoring. Only relative luminance controls anchoring: The lighter region appears white, and the darker region is perceived relative to that value. When the area of the darker region becomes greater than that of the lighter region, relative area begins to play a role. As the darker region becomes larger and relative area shifts from the lighter region to the darker region, the appearance of the darker region moves toward white and the appearance of lighter region moves toward luminosity. This hitherto unrecognized rule is consistent with almost all of the many previous reports of area effects in lightness and brightness. This in turn suggests that a wide range of earlier work on area effects in brightness induction, lightness contrast, lightness assimilation, and luminosity perception can be understood in terms of a few simple rules of anchoring.  相似文献   
187.
Understanding the neurophysiological mechanisms of learning is important for both fundamental and clinical neuroscience. We present a neurophysiologically inspired framework for understanding cortical mechanisms of feedback-guided learning. This framework is based on dynamic changes in systems-level oscillatory synchronization, reflecting changes in synaptic plasticity between stimulus-processing and motor areas that are modulated in a top-down fashion by different areas of the prefrontal cortex. We make new and testable predictions for how large-scale cortical networks support learning from feedback. Testing these predictions may provide new insights into the basic mechanisms underlying learning and how these mechanisms may be impaired in clinical disorders in which feedback learning is compromised.  相似文献   
188.
T. E. Moffitt's (1993a) hypothesis that adolescent-limited criminal offenders will have higher scores on tests of cognitive ability than life-course-persistent offenders was tested with 12 tests of cognitive ability given to a large and diverse sample of delinquent juveniles whose arrest records were collected over 20 years. This is the first investigation to empirically evaluate this proposal with longitudinal data obtained from a sample for a long enough time to distinguish life course patterns of crime. This study provided only partial support for Moffitt's hypothesis because the results varied by ethnicity. We found relatively consistent support for the hypothesis for Caucasians and Hispanics but no support for the hypothesis for African Americans. These findings are interpreted in terms of differences in developmental contexts for individual ethnic groups.  相似文献   
189.
The Drosophila giant fiber jump-and-flight escape response is a model for genetic analysis of both the physiology and the plasticity of a sensorimotor behavioral pathway. We previously established the electrically induced giant fiber response in intact tethered flies as a model for habituation, a form of nonassociative learning. Here, we show that the rate of stimulus-dependent response decrement of this neural pathway in a habituation protocol is correlated with PKG (cGMP-Dependent Protein Kinase) activity and foraging behavior. We assayed response decrement for natural and mutant rover and sitter alleles of the foraging (for) gene that encodes a Drosophila PKG. Rover larvae and adults, which have higher PKG activities, travel significantly farther while foraging than sitters with lower PKG activities. Response decrement was most rapid in genotypes previously shown to have low PKG activities and sitter-like foraging behavior. We also found differences in spontaneous recovery (the reversal of response decrement during a rest from stimulation) and a dishabituation-like phenomenon (the reversal of response decrement evoked by a novel stimulus). This electrophysiological study in an intact animal preparation provides one of the first direct demonstrations that PKG can affect plasticity in a simple learning paradigm. It increases our understanding of the complex interplay of factors that can modulate the sensitivity of the giant fiber escape response, and it defines a new adult-stage phenotype of the foraging locus. Finally, these results show that behaviorally relevant neural plasticity in an identified circuit can be influenced by a single-locus genetic polymorphism existing in a natural population of Drosophila.  相似文献   
190.
常用的多层线性模型要求因变量是服从正态分布的连续变量,却无法处理因变量为离散变量的嵌套数据.多层多项Logit模型能够处理因变量是无序多分类的多层嵌套数据,但这一模型在我国心理学研究中却鲜有介绍和应用.研究简要介绍了多层多项Logit模型的原理、参数估计和假设检验,然后分别用该模型和传统Logistic回归模型探讨个体因素和区域因素对35721名学生进入不同高校就读机会的影响并对结果进行了解释,结果表明多层多项Logit模型比传统Logistic回归模型更拟合数据.  相似文献   
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