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251.
超声检查具有实时、动态、灵活、方便等优点,在临床上有重要作用.介入性超声是在超声显像的基础上,为进一步满足临床诊断和治疗的需要而发展起来的一门新技术,在微创医学体系中占有非常重要的地位,但只有与其它微创技术联合应用才更有活力和生机. 相似文献
252.
253.
Is learning of a complex functional relationship enhanced by trying to predict what output will go with a given input, as
compared to studying an input–output pair? We examined learning of a bilinear function and transfer to new items outside the
trained range. Subjects either saw the input–output pairs (study-only condition) or attempted to guess the output and then
saw the pair (test/study condition). The total study times were equated, and motivation was enhanced with a monetary bonus.
Performance was markedly better for the test/study condition, both within the trained range and in the transfer test. This
benefit of testing during training was observed on a criterial test administered shortly after training. Testing has long
been shown to enhance the explicit learning and retention of verbal material; our present findings reveal a novel domain for
which testing can also be advantageous—that is, function learning. 相似文献
254.
Jianfeng Zhao Avraam A. Konstantinidis Guozheng Kang 《Philosophical Magazine Letters》2015,95(6):340-349
The internal length is the governing parameter in strain gradient theories which among other things have been used successfully to interpret size effects at the microscale. Physically, the internal length is supposed to be related with the microstructure of the material and evolves during the deformation. Based on Taylor hardening law, we propose a power-law relationship to describe the evolution of the variable internal length with strain. Then, the classical Fleck–Hutchinson strain gradient theory is extended with a strain-dependent internal length, and the generalized Fleck–Hutchinson theory is confirmed here, by comparing our model predictions to recent experimental data on tension and torsion of thin wires with varying diameter and grain size. Our work suggests that the internal length is a configuration-dependent parameter, closely related to dislocation characteristics and grain size, as well as sample geometry when this affects either the underlying microstructure or the ductility of the material. 相似文献
255.
姬永亮 《医学与哲学(人文社会医学版)》2020,41(10):67-71
《中国科学技术史·年表卷》作为近年出版的一部相当重要的科学技术史领域的年表类工具书,载录了较为丰富的反映北宋时期医学发展历程的重大事件,但是其中部分内容的陈述与史实不甚相符。分别从原始文献、二手文献入手,重新辨析该书相关内容在人物、时代、职官、著作等方面的谬误。并给出今后提升编撰质量的建议,一方面在撰稿时理应反复核实各种原始文献与二手材料,另一方面在转述学界研究成果时应当尽量做到细致认真,还应兼收并蓄,尽可能全面地列举出学术界尚未达成共识、意见相左的观点。 相似文献
256.
介绍英国公众与患者参与研究领域的成熟经验,梳理近年来公众与患者参与在英国医学研究中的相关实践活动,包括最新出台的英国国家《公众参与研究标准》,公众与患者如何作为研究的合作者,主动参与研究优先事项及研究问题、研究申请、研究设计、研究实施、成果发布及应用和评估等环节共享决策权,如何制定和建设公众与患者参与的策略等。期望我国医学研究相关各方关注并倡导公众参与研究的理念,并对建立公众参与机制有所思考。 相似文献
257.
采用交叉滞后设计,使用学业成绩自我评定量表、青少年生活事件量表的学业分量表以及青少年早期气质量表的意志控制分量表对1263名青少年进行间隔两年的两次测查,考察青少年学业成绩不良、学业压力与意志控制的关系。潜变量交叉滞后分析发现,青少年的意志控制显著负向预测两年后的自我感知学业成绩不良,自我感知的学业成绩不良无法显著预测日后的意志控制;学业压力显著负向预测日后的意志控制,意志控制无法显著预测日后的学业压力。这些结果表明,青少年学业领域发展与自我调控能力发展间存在动态联系。 相似文献
258.
Sara R. Westbrook Minsu Kang Luke K. Sherrill Dylan O'Hearn Tanya Krishnamani Joshua M. Gulley 《Journal of the experimental analysis of behavior》2018,110(1):54-62
Rodent models have been especially useful for investigating adolescent ethanol exposure. However, there is a paucity of studies examining sex differences in behavioral intoxication from adolescent ethanol drinking. Here, we used an ethanol drinking model to investigate if adolescent rats of both sexes readily drink ethanol to measurable behavioral intoxication, indicated by increased impulsive action and motor incoordination. Beginning on postnatal day (P) 28, male and female Long‐Evans rats were given 30‐min access to a solution of sucrose (20%) or sweetened ethanol (20% sucrose +15% ethanol) every other day until P60 and once after 2 weeks of forced abstinence (on P75). On alternate (nondrinking) days, rats were reinforced with a food pellet for making a cued nosepoke response. Beginning on P56, rats were tested in this task after drinking sessions to assess ethanol‐induced changes in impulsive action, defined as premature responding prior to cue presentation. Motor coordination was assessed before and after drinking sessions using an incline plane test. Adolescent male and female rats readily consumed ethanol to behavioral intoxication, measured as reduced motor coordination. Following forced abstinence, females displayed greater ethanol‐induced impulsive action. These studies provide evidence for sex differences in behavioral intoxication following adolescent ethanol drinking. 相似文献
259.
Cocaine is a type of drug that functions to increase the availability of the neurotransmitter dopamine in the brain. However, cocaine dependence or abuse is highly related to an increased risk of psychiatric disorders and deficits in cognitive performance, attention, and decision-making abilities. Given the chronic and persistent features of drug addiction, the progression of abstaining from cocaine often evolves across several states, such as addiction to, moderate dependence on, and swearing off cocaine. Hidden Markov models (HMMs) are well suited to the characterization of longitudinal data in terms of a set of unobservable states, and have increasingly been used to uncover the dynamic heterogeneity in progressive diseases or activities. However, the existence of outliers or influential points may misidentify the hidden states and distort the associated inference. In this study, we develop a Bayesian local influence procedure for HMMs with latent variables in the presence of missing data. The proposed model enables us to investigate the dynamic heterogeneity of multivariate longitudinal data, reveal how the interrelationships among latent variables change from one state to another, and simultaneously conduct statistical diagnosis for the given data, model assumptions, and prior inputs. We apply the proposed procedure to analyze a dataset collected by the UCLA center for advancing longitudinal drug abuse research. Several outliers or influential points that seriously influence estimation results are identified and removed. The proposed procedure also discovers the effects of treatment and individuals’ psychological problems on cocaine use behavior and delineates their dynamic changes across the cocaine-addiction states. 相似文献
260.
We investigated how the ability to deceive emerges in early childhood among a sample of young preschoolers (Mean age = 34.7 months). We did this via a 10‐session microgenetic method that took place over a 10‐day period. In each session, children played a zero‐sum game against an adult to win treats. In the game, children hid the treats and had opportunities (10 trials) to win them by providing deceptive information about their whereabouts to the adult. Although children initially showed little or no ability to deceive, most spontaneously discovered deception and systematically used it to win the game by the tenth day. Both theory of mind and executive function skills were predictive of relatively faster patterns of discovery. These results are the first to provide evidence for the importance of cognitive skills and social experience in the discovery of deception over time in early childhood. 相似文献