SAwSu: An Integrated Model of Associative and Reinforcement Learning

Successfully explaining and replicating the complexity and generality of human and animal learning will require the integration of a variety of learning mechanisms. Here, we introduce a computational model which integrates associative learning (AL) and reinforcement learning (RL). We contrast the integrated model with standalone AL and RL models in three simulation studies. First, a synthetic grid‐navigation task is employed to highlight performance advantages for the integrated model in an environment where the reward structure is both diverse and dynamic. The second and third simulations contrast the performances of the three models in behavioral experiments, demonstrating advantages for the integrated model in accounting for behavioral data.     

应用分子靶向治疗的时机选择

分子靶向药物的出现显示出肿瘤治疗传统模式的重要进展。与传统放疗、化疗相比,分子靶向治疗因其特异性高、不良反应轻微,在恶性肿瘤个体化治疗中扮演重要角色。十五年来,分子靶向药物的出现,给肿瘤的治疗模式带来重大改变,也给临床医生带来新的挑战。准确把握分子靶向药物应用时机,获得最大临床效果,已成为肿瘤治疗领域关注热点。本文就非小细胞肺癌、消化系统肿瘤、乳腺癌、肾癌治疗中分子靶向药物如何选择应用时机进行阐述。     

医学影像学见习应用PACS教学法与传统读片教学法的对比研究

将中南大学湘雅医学院2010级临床医学五年制197名学生随机分成两组,在医学影像学见习教学过程中分别应用影像存储及传输系统（PACS）教学法（98人）及传统读片教学法（99人）,学期结束时对两组学生考试成绩进行分析,并对PACS组学生进行问卷调查及结果分析.统计数据显示,PACS组学生读片测验及卷面考试中,病例分析题成绩显著高于传统读片组,问卷调查显示PACS组学生大多数认可该教学方法.因此,应用PACS教学有助于提高学生的临床分析能力及主动学习的能力,是学生欢迎的教学方式.但对医学影像学基本知识的传授,应用PACS法较传统读片法并无明显优势.     

人工肝支持系统治疗肝衰竭的研究进展

目前肝衰竭发病率和病死率仍然较高,肝衰竭成为威胁患者生命的严重疾病。基于肝脏具有强大再生能力,人工肝支持系统作为一种“过渡”措施,为肝衰竭患者的肝功能恢复赢得时间。人工肝支持系统根据性质不同分为非生物型人工肝、生物型人工肝和混合型人工肝。目前非生物型人工肝已在肝病治疗领域被广泛应用,但生物型及混合型人工肝的临床应用还存在很多问题需要进一步研究和解决。因此本文对人工肝的作用、临床应用现状、存在问题及研究进展进行综述。     

ITC Guidelines on Quality Control in Scoring,Test Analysis,and Reporting of Test Scores

The Quality Control (QC) Guidelines are intended to increase the efficiency, precision, and accuracy of the scoring, analysis, and reporting process of testing. The QC Guidelines focus on large-scale testing operations where multiple forms of tests are created for use on set dates. However, they may also be used for a wide variety of other testing situations and assessment techniques and for almost any situation in which assessment occurs. The QC Guidelines are applicable in any form of test administration, including paper and pencil tests and the ever-increasing computerized assessments via the Internet or offline.     

Executive functions,impulsivity, and inhibitory control in adolescents: A structural equation model

Background. Adolescence represents a critical period for brain development, addressed by neurodevelopmental models to frontal, subcortical-limbic, and striatal activation, a pattern associated with rise of impulsivity and deficits in inhibitory control. The present study aimed at studying the association between self-report measures of impulsivity and inhibitory control with executive function in adolescents, employing structural equation modeling. Method. Tests were administered to 434 high school students. Acting without thinking was measured through the Barratt Impulsiveness Scale and the Dickman Impulsivity Inventory, reward sensitivity through the Behavioral Activation System, and sensation seeking through the Zuckerman–Kuhlman–Aluja Personali- ty Questionnaire. Inhibitory control was assessed through the Behavioral Inhibition System. The performance at the Wisconsin Card Sorting Task indicated executive function. Three models were specified using Sample Covariance Matrix, and the estimated parameters using Maximum Likelihood. Results. In the final model, impulsivity and inhibitory control predicted executive function, but sensation seeking did not. The fit of the model to data was excellent. Conclusions. The hypothesis that inhibitory control and impulsivity are predictors of executive function was supported. Our results appear informative of the validity of self-report measures to examine the relation between impulsivity traits rather than others to regulatory function of cognition and behavior.     

Long-term response-stimulus associations can influence distractor-response bindings

Strong associations between target stimuli and responses usually facilitate fast and effortless reactions. The present study investigated whether long-term associations between distractor stimuli and responses modulate behavior. In particular, distractor stimuli can affect behavior due to distractor-based stimulus-response retrieval, a phenomenon called distractor-response binding: An ignored stimulus becomes temporarily associated with a response and retrieves it at stimulus repetition. In a flanker task, participants ignored left and right pointing arrows and responded to a target letter either with left and right (strongly associated) responses or with upper and lower (weakly associated) responses. Binding effects were modulated in dependence of the long-term association strength between distractors and responses. If the association was strong (arrows pointing left and right with left and right responses), binding effects emerged but only in case of compatible responses. If the long-term association between distractors and responses was weak (arrows pointing left and right with upper and lower responses), binding was weaker and not modulated by compatibility. In contrast, sequential compatibility effects were not modulated by association strength between distractor and response. The results indicate that existing long-term associations between stimuli responses may modulate the impact of an ignored stimulus on action control.     

论公共管理中不道德手段的生成与控制

公共生活要得到有效而又合理的管理必须运用道德的手段。有的公共管理机构及其人员出于提高管理效率或者实现私人目的的考虑,可能会选择不道德的手段。由于不道德的手段会造成严重的道德后果,因此,就有必要对其予以合理控制。这种控制既需要合理的道德观念的支持,又需要刚性的内部控制与外部控制的配合。     

Stimulus control of differential-reinforcement-of-low-rate responding

Five pigeons were given single-stimulus training on an 8-sec differential-reinforcement-of-low-rate schedule followed by steady-state generalization training using 12 wavelength stimuli. Three birds had a high percentage of reinforced responses on the training schedule and flat generalization gradients of total responses. The birds with fewer reinforced responses had much steeper generalization gradients. Generalization gradients plotted as a function of both stimulus wavelength and interresponse time showed that for most birds, stimulus control was restricted to responses with long interresponse times. Responses with very short interresponse times were not under stimulus control and there was some evidence of inhibitory control of short interresponse times. Interresponse-times-per-opportunity functions, plotted as a function of stimulus wavelength, showed that stimulus wavelength controlled the temporal distribution of responses, rather than the overall rate of response. The data indicate that the differential-reinforcement-of-low-rate schedule generates several response categories that are controlled in different ways by wavelength and time-correlated stimuli, and that averaging responses regardless of interresponse-time length obscures this control.     

The update of semantic memories in amnestic mild cognitive impairment

It is still controversial to what extent neocortical consolidated memories are susceptible of change by processes of reconsolidation and transformation throughout experience, and whether the medial temporal lobes are necessary for this update of semantic consolidated memories, as they are for episodic remembering. We hypothesize that patients with amnestic mild cognitive impairment (aMCI) who have deficits in episodic memory may also have difficulties in updating information on added new features of objects. Sixteen participants with aMCI and 20 healthy control participants performed a semantic word-to-picture task, in which they were asked to identify as belonging to a given semantic category NEW objects, that have incorporated novel features, as well as OLD items, semantically and visually SIMILAR items and UNRELATED items. Patients with aMCI made a greater percentage of errors than healthy controls. Participants globally made greater percentages of errors in difficult types of items, namely NEW and SIMILAR, as compared to easier ones, OLD and UNRELATED. Importantly, an item by diagnostic group interaction effect was observed, and post hoc analysis showed that patients with aMCI made a higher percentage of errors than controls in NEW items only. In conclusion, patients with aMCI had a particular difficulty in identifying the NEW items of the word-to-picture task as compared to the control participants, supporting the concept of a flexible and dynamic conceptual knowledge system, involving the update of semantic memories and the integration of new attributes in a constant transformation process, which is impaired in these patients.