NOTE ON THE SUBJECTIVE SPEED OF MANUAL WORK

A preliminary experiment is described, in which the speed of three manual activities was estimated by the method of magnitude estimation. Within the rather narrow stimulus range of 1/1.35 the subjective range was 1/1.86 for card dealing, 1/1.64 for shoveling gravel, and 1/1.41 for packing. Tentative interpretations of these differences are discussed.     

Structural Constraints on the Performance of Symmetrical Bimanual Movements with Different Amplitudes

In bimanual movements the amplitude of each hand's movement often depends on the concurrent amplitude of the other hand's movement such that both amplitudes become similar (amplitude coupling). We tested the hypothesis that the strength of amplitude coupling depends on the tempo of performance of a movement sequence, a hypothesis based on a model of bimanual coordination that holds that cross-talk occurs at the execution level as well as at the programming level. Subjects performed bimanual periodic arm movements on two digitizers. In nine conditions constant small, constant large, and alternating small and large amplitudes of each arm were orthogonally combined. Overall tempo was varied by instructing subjects to increase the tempo progressively by 10%. Clear tempo-dependent modulations of the amplitude were observed in movements with instructed constant amplitude when the other hand performed alternating amplitudes. The effect of the size of constant-amplitude movements on the mean amplitude of the other hand indicated cross-talk at the execution level. Cross-talk at the programming level was revealed by the dependence of the current amplitude on the change in the amplitude of the other hand in the preceding cycle. Finally, asymmetric cross-manual effects were observed.     

Assisted Suicide,Euthanasia, and Suicide Prevention: The Implications of the Dutch Experience

What impact would legalization of assisted suicide and euthanasia have on our ability to treat suicidal patients and to prevent suicide? Information from a study of the Dutch experience illustrates how legal sanction promotes a culture that transforms suicide into assisted suicide and euthanasia and encourages patients and doctors to see choosing death as a preferred way of dealing with serious or terminal illness. The extension of the right to euthanasia to those who are not physically ill further complicates the problem. So too does the tendency of doctors in such a culture to begin to feel that they can make decisions about ending the life of competent terminally ill patients without consulting the patient. “Normalizing” suicide as a medical option lays the groundwork for a society that turns euthanasia into a “cure” for suicidal depression.     

Testing for DIF in a model with single peaked item characteristic curves: The parella model

The PARELLA model is a probabilistic parallelogram model that can be used for the measurement of latent attitudes or latent preferences. The data analyzed are the dichotomous responses of persons to items, with a one (zero) indicating agreement (disagreement) with the content of the item. The model provides a unidimensional representation of persons and items. The response probabilities are a function of the distance between person and item: the smaller the distance, the larger the probability that a person will agree with the content of the item. This paper discusses how the approach to differential item functioning presented by Thissen, Steinberg, and Wainer can be implemented for the PARELLA model. Requests for the PARELLA software should be sent to Iec Progamma PO Box 841, 9700 AV Groningen, The Netherlands.     

生物库管理:如何避免失败

近年来,生物库成为了人们关注的焦点,因为生物库已经成为了生物制药和药学研究领域新的必备基础和来源。生物库所承载的历史使命是极具挑战性的,甚至有些令人望而却步:它既要将现有生物样本库转化成基因学研究的新的研究工具,又要建立大规模人群生物库。建立或维护生物库不仅仅是一项简单的收集工作,而是要通过生物库管理来赋予其特定的知识价值,这种知识价值可以产生相应的医疗健康意义或某种经济价值。生物库的成败与否,生物库创造价值的能力,取决于管理体系的确立和有序模式的建立,其建立可以为分类提供策略,并最终建立一个互动的网络体系,这个互动网络体系呈现在一系列不同的领域中:科学/技术领域,医药/卫生领域,产业化经济领域,法律道德和社会政治领域。