Nonlocal effects in the continuum theory of shear localisation in 2d foams

Goyon et al. [J. Goyon, A. Colin, G. Ovarlez, A. Ajdari and L. Bocquet, Nature 454 (2008) p. 84] have shown that nonlocal effects in the rheology of foams may be accounted for by a modification of the standard (Herschel–Bulkley) model. Here we consider the effects of this modification on the continuum theory of 2d shear localisation. We compute results for various examples, showing that the localisation length is increased, and explore the limiting cases of zero and infinite nonlocality length ξ. Velocity profiles are shown to take an exponential form in the case where ξ is large. As the formulation of the nonlocal continuum model presented in this article is general, it may also be directly applicable to other complex fluids.     

The Duhem‐Quine thesis revisited

The Duhem‐Quine thesis is generally presented as the radical underdetermi‐ nation of a theory by experimental evidence. But there is a much‐neglected second aspect, i.e. the coherence or interrelatedness of the conceptual components of a theory. Although both Duhem and Quine recognised this aspect, they failed to see its consequences: it militates against the idea of radical underdetermination. Because scientific theories are coherent conceptual systems, empirical evidence penetrates, as it were, the periphery and allows the localisation of central, not just peripheral hypotheses. There is then no reason to deny the existence of crucial experiments. Both these ideas are denied in the Quine‐Duhem thesis. A discussion of the famous Stem‐Gerlach experiment and the role of fundamental physical constants shows, however, that localisation is not only possible but essential for the validity of scientific theories. Quine's famous ‘latitude of choice’ turns out to be severely restricted.     

社交电商中的社交-消费转换机制

社交情境和消费情境之间可以相互转换是社交电商的重要特征, 然而这种相互转换在现有社交电商采纳行为研究中却没有得到应有的重视。社交-消费转换概念的提出很好地弥补了上述研究不足。社交-消费转换是指用户从社交情境到消费情境的转换过程。基于边界理论, 从社群和用户两方面系统分析社交-消费转换的影响因素与促进机制, 有望构建体现社交电商专属特性的新理论, 帮助人们更加完整地理解社交电商采纳行为, 并为促进社交-消费转换提供切实可行的实践建议。研究内容具体包括以下4个方面：(1)社交电商中社交-消费转换的内涵与外延; (2)社群边界整合供给对整合型社交边界与社交-消费转换的影响; (3)用户边界分割偏好对整合型社交边界与社交-消费转换的影响; (4)社群边界定制氛围对整合型社交边界与社交-消费转换关系的调节作用。     

Object localisation and frames of reference

In this paper, we explore which spatial frames of reference, egocentric or allocentric, are used to locate objects either in relation to ourselves (i.e. subject-to-object localisation) or to other objects (i.e. object-to-object localisation). In particular, we wanted to know whether the same or different frames of reference are used in these two different kinds of localisation after learning the environment in an egocentric way. Egocentric frames of reference are determined by the position of the person in relation to the spatial layout, whereas allocentric frames of reference are centred on the environment or on objects, independent of a persons position. We hypothesised that subject-to-object localisation is based on egocentric spatial representations, whereas object-to-object localisation is based on allocentric spatial representations. Participants were asked to study eight common objects, placed in a circle. Next, half of the participants had to point to an object in relation to their imagined position (egocentric condition) and the other half to an object in relation to another object (allocentric condition). The overall results show no difference between subject-to-object and object-to-object localisation. In both cases, access to positions corresponding to the front/back body axis was facilitated, in terms of both latency and error. Moreover, participants were able to retrieve objects positions better from the perspective from which they had learned the spatial array than from new perspectives. These results support the conclusion that egocentric coordinates, which are selected on the basis of our body-centred experience of the environment, define spatial representations underlying both subject-to-object and object-to-object localisation.     

Flexing Work Boundaries: The Spillover and Crossover of Workplace Support

Using boundary theory and conservation of resources theory, we examined how job incumbents’ perceptions of supervisor instrumental support and organizational segmentation support influence outcomes for both the incumbent and the spouse. First, we examined how supervisor instrumental support and organizational segmentation support shape incumbents’ perceived ability to flex work boundaries and thus affect their experience of family functioning and their organizational commitment. Second, we examine the effects of supervisor instrumental support and organizational segmentation support on spousal martial satisfaction and the spouse's commitment to the incumbent's employing organization as mediated through boundary flexibility and the spouse's perception of successful boundary management by the incumbent. Using a matched set of 503 subordinates and their spouses, this study found that both supervisor instrumental support and organizational segmentation support contribute to work boundary flexibility. Further, for the incumbent, family functioning and organizational commitment were enhanced through work boundary flexibility, whereas for the spouse, marital satisfaction and commitment to the incumbent's organization were enhanced through both incumbent work boundary flexibility and the spouse's perception of successful boundary management by the incumbent. We discuss the study's implications for theory, research, and practice while suggesting new research directions.     

Fiduciary Duty and Boundaries: Acting in the Client's Best Interest

The task of defining boundaries and boundary violations in the therapeutic relationship is examined from several perspectives. This paper reviews the ethical rules of the major mental health associations and the American Medical Association to determine the professions' ethical positions with regard to boundary maintenance and boundary violations. It also analyzes judicially sanctioned causes of action for recovery by clients for damages suffered as a result of boundary violations. The authors examine the ways in which fiduciary theory is used in the formulation of the ethical rules and to support the imposition of civil liability for boundary violations. The authors conclude that fiduciary theory provides a useful paradigm for setting and evaluating boundaries that acknowledge and address the fiduciary nature of the therapist–client relationship. The authors point out that measuring boundary violations with the yardstick of fiduciary duty serves the interests of both the client and the therapist. © 1997 John Wiley & Sons, Ltd.     

Effects of boundary height and horizontal size within boundary on perceived enclosure

The permeability theory of environmental design predicts that perceived enclosure will be more strongly related to boundary properties such as height as opposed to the size of a horizontal area within a boundary. An experiment on perceived enclosure, provided by 24 participants on 12 spaces in a park, indicated that enclosure correlated at .85 with boundary height and -.60 with horizontal area. These results were as predicted by permeability theory.     

An empirical look at the Defence Mechanism Test (DMT) Stimulus effects

Based on a sample of non-clinical subjects (N=74) the study examines the Defence Mechanism Test (DMT) by focusing on when perceptual distortions, called ‘signs of defence’ in DMT terminology, occur (distribution in exposure duration), which part of the picture is involved (distribution in localisation), and which ‘signs’ go together (using correlation and factor analyses). The results disclosed that the occurrence of perceptual distortions (‘signs of defence’) was related to exposure duration (some ‘defences’ are more frequent at brief exposures, some others at longer exposure durations), and to localisation on the picture. The location of misperceptions to the central person (hero) or the peripheral person (pp) of the picture was the major explanatory principle for the distribution of ‘signs’ on factors. Rather than capturing psychodynamic defence mechanisms, which is the theoretical basis of the test, the analyses imply that the DMT seems to measure misperceptions which are a function of the localisation of persons on the stimulus picture and of exposure durations.     

Influence of plastic strain localisation on the mechanical properties of metal matrix composites

The aim of the present study is to reveal the most critical underlying factor influencing the mechanical properties of metal matrix composites (MMCs). It is shown that the mechanical properties of MMCs are essentially governed by the degree of strain localisation during plastic deformation. In other words, the MMCs exhibit superior mechanical performance only if the strain localisation is obviously inhibited and the accumulated stresses can be effectively transferred out. The work provides a new perspective in guiding the design of next-generation high-performance MMCs by suppressing the strain localisation as far as possible.     

Family boundary ambiguity: a new variable in family stress theory

The variable, degree of family boundary ambiguity, is increasingly being used in family research to describe and predict the effects of family membership loss and change over time. Boundary ambiguity is defined as the family not knowing who is in and who is out of the system. The family may perceive a physically absent member as psychologically present or a physically present member as psychologically absent. In either case, the family boundary is ambiguous. This review is presented to clarify the meaning of boundary ambiguity and to explore its scope and application as a variable. We focus here on (a) the process of theory development, inductive and deductive, by which the construct of boundary ambiguity was identified and validated as a continuous variable within family stress theory; (b) the historical antecedents of the construct; and (c) the interrelationships of the variable with other factors related to stressed families.     

God’s silence

Vagueness manifests itself (among other things) in our inability to find boundaries to the extension of vague predicates. A semantic theory of vagueness plans to justify this inability in terms of the vague semantic rules governing language and thought. According to a supporter of semantic theory, the inability to find such a boundary is not dependent on epistemic limits and an omniscient being like God would be equally unable. Williamson (Vagueness, 1994) argued that cooperative omniscient beings adequately instructed would find a precise boundary in a sorites series and that, for this reason, the semantic theory misses its target, while Hawthorne (Philosophical Studies 122:1–25, 2005) stood with the semantic theorists and argued that the linguistic behaviour of a cooperative omniscient being like God would clearly demonstrate that he does not find a precise boundary in the sorites series. I argue that Hawthorne’s definition of God’s cooperative behaviour cannot be accepted and that, contrary to what has been assumed by both Williamson and Hawthorne, an omniscient being like God cannot be a cooperative evaluator of a semantic theory of vagueness.     

Probing the human brain with stimulating electrodes: The story of Roberts Bartholow’s (1874) experiment on Mary Rafferty

Roberts Bartholow’s 1874 experiment on Mary Rafferty is widely cited as the first demonstration, by direct application of stimulating electrodes, of the motor excitability of the human cerebral cortex. The many accounts of the experiment, however, leave certain questions and details unexamined or unresolved, especially about Bartholow’s goals, the nature and quality of the evidence, and the experiment’s role in the history of theory and research on localisation of function. In this article, we try to fill these gaps and to tell the full story. We describe Bartholow’s career up to 1874, review the theoretical and empirical background for the experiment, and present Bartholow’s own account of the experiment as well as those of his supporters and critics. We then present our own analysis, assess the experiment’s influence on contemporaneous scientific opinion about cortical excitability, and trace its citation record into our own time. We also review and assess ethical criticisms of Bartholow and their effects on his career, and we close by discussing the role we think the experiment deserves to play in the history of theory and research on cortical excitability.     

隔代教育对孙辈和祖辈的影响：双刃剑效应

隔代教育是指祖辈对孙辈的抚养和教育, 随着经济社会的发展, “隔代教育”已成为“亲代教育”的一种重要补充形式。隔代教育对祖孙两辈人的身心健康均存在“双刃剑”效应。生物进化论、社会交换理论和家庭系统理论为理解隔代教育对孙辈的影响提供了理论支持, 角色紧张和角色强化理论可以加深隔代教育对祖辈影响的认识。未来研究应明确隔代教育的定义和类型, 控制边界因素进行更为深入的综合性研究, 并进一步推进隔代教育的本土化研究。     

Magnetoencephalography--current trends

The review deals with the method of magnet-encephalography. The physical principles and the most important technical conditions to put into practice this method are mentioned. Comparing with the electroencephalography this method shows various advantages, what leads to its intensive use for the localisation of components of evoked potentials, for the magnet-encephalographic record of the brain activity of the human fetus, and for the localisation of epileptic foci in therapy resistant epileptics.     

History and future directions of human brain mapping and functional neuroimaging

It has long been known that there is some degree of localisation of function in the human brain, as indicated by the effects of traumatic head injury. Work in the middle of the 20th century, notably the direct cortical stimulation of patients during neurosurgery, suggested that the degree and specificity of such localisation of function were far greater than had earlier been imagined. One problem with the data based on lesions and direct stimulation was that the work depended on the study of what were, by definition, damaged brains. During the second half of the 20th century, a collection of relatively non-invasive tools for assessing and localising human brain function in healthy volunteers has led to an explosion of research in what is often termed "Brain Mapping". The present article reviews some of the history associated with these tools, but emphasises the current state of development with speculation about the future.     

From dichoptic to dichotic: historical contrasts between binocular vision and binaural hearing

Phenomena involving vision with two eyes have been commented upon for several thousand years whereas those concerned with hearing with two ears have a much more recent history. Studies of binocular vision and binaural hearing are contrasted with respect to the singleness of the percept, experimental manipulations of dichoptic and dichotic stimuli, eye and ear dominance, spatial localisation, and the instruments used to stimulate the paired organs. One of the principal phenomena that led to studies of dichotic hearing was dichoptic colour mixing. There was similar disagreement regarding whether colours or sounds could be combined when presented to different paired organs. Direction and distance in visual localisation were analysed before those for auditory localisation, partly due to difficulties in controlling the stimuli. Instruments for investigating binocular vision, like the stereoscope and pseudoscope, were invented before those for binaural hearing, like the stethophone and pseudophone.     

Metacognition in psychophysical judgment: An unfolding view of comparative judgments of mental workload

An experiment is reported in which it was found that when subjects were required to indicate which of two visual extents was more difficult to categorize as “long” or “short,” they executed these categorizations and then measured the distance of the representation of each stimulus from the long-short category boundary; the stimulus nearer the boundary was judged to be the more difficult. When they were requested to indicate which was easier to categorize, they selected the alternative that was farther. Coombs’s theory of data (1952, 1964) and his unfolding theory of preferential choice (1950, 1964) provided the conceptualization of metacognition in this psychophysical task context. Strong support for the probabilisitic version of unfolding theory was obtained from the observed selective effects of laterality on the levels of stochastic transitivity attained for various classes of triples and the reliably longer times for comparisons with bilateral pairs than with unilateral pairs. The semantic congruity effects obtained, together with the changes in the form of the relationship between probability and response time as a function of practice, can be best accounted for by an evidence accrual theory in which the distances from the active reference point are measured and compared with a criterion on each evidence accrual. No support is provided for the view that propositionally based semantic “ease”- “difficulty” codes serve as the basis for these metacognitive comparative judgments of ease and difficulty.     

Metacognition in psychophysical judgment: an unfolding view of comparative judgments of mental workload.

An experiment is reported in which it was found that when subjects were required to indicate which of two visual extents was more difficult to categorize as "long" or "short," they executed these categorizations and then measured the distance of the representation of each stimulus from the long-short category boundary; the stimulus nearer the boundary was judged to be the more difficult. When they were requested to indicate which was easier to categorize, they selected the alternative that was farther. Coombs's theory of data (1952, 1964) and his unfolding theory of preferential choice (1950, 1964) provided the conceptualization of metacognition in this psychophysical task context. Strong support for the probabilistic version of unfolding theory was obtained from the observed selective effects of laterality on the levels of stochastic transitivity attained for various classes of triples and the reliably longer times for comparisons with bilateral pairs than with unilateral pairs. The semantic congruity effects obtained, together with the changes in the form of the relationship between probability and response time as a function of practice, can be best accounted for by an evidence accrual theory in which the distances from the active reference point are measured and compared with a criterion on each evidence accrual. No support is provided for the view that propositionally based semantic "ease"-"difficulty" codes serve as the basis for these metacognitive comparative judgments of ease and difficulty.     

Linking Availability Expectations,Bidirectional Boundary Management Behavior and Preferences,and Employee Well-Being: an Integrative Study Approach

Information and communication technologies enable employees to be available anywhere and anytime, raising availability expectations of work and nonwork contacts. Building on the theory of planned behavior and the person-environment fit theory, the present study examines how others’ availability expectations predict employees’ management of work and nonwork boundaries, and how these bidirectional boundary management behaviors relate to well-being. Results of structural equation modeling with data from 401 employees collected in two waves show that availability expectations of both coworkers and nonwork contacts predict how employees manage the boundaries of work and nonwork domains. Thereby, availability expectations are negatively related to segmentation of the two domains and coworkers' expectations show an indirect effect on employee well-being. Further, our study shows that work-nonwork and nonwork-work segmentation behavior have divergent effects on employee well-being, indicating that asymmetric boundary management behavior with high work-nonwork segmentation and low nonwork-work segmentation may be beneficial. Besides, moderation analyses underline the importance of enabling individuals to align their boundary management preferences with their actual behavior, especially when individuals have high work-nonwork segmentation preferences. By integrating and unveiling distinct antecedents of work-nonwork and nonwork-work segmentation behavior and their divergent effects on well-being, the present study contributes to a comprehensive framework for investigating and understanding bidirectional boundary management in the face of technology-enabled availability.

     

Dispersion in models of categorical perception

A signal detection theory model of auditory discrimination with a nonlinear mapping from stimulus continuum to perceptual continuum can account for the enhanced discrimination at the category boundary found in categorical perception. Properties of this transformation are specified by a unimodal “dispersion function”. Furthermore, it is shown that a system consisting of two acoustic feature detectors with an associated decision function is also a dispersive system, which models categorical perception of a stimulus continuum as well as boundary shifts under adaptation. The effect of detector adaptation on discrimination is discussed in view of three different types of decision variable and different types of detector noise.