Manipulation of vision while learning a sensory driven motor task: establishing a boundary to the specificity of practice hypothesis

It has been suggested that learning is specific to the source of information available during practice (Proteau, Marteniuk, & Levesque, 1992). This hypothesis is quite robust for rapid aiming tasks that have defined spatial and temporal goals, but it is unclear whether it extends to tasks that are more sensory driven and with no clear spatio-temporal goal, such as ball balancing. In this experiment, 24 young adults practiced balancing a ball on their thumb and forefinger either with or without vision. Performance was measured early in practice (after 40 min.) and late in practice (after 180 min.) in both conditions. Both groups improved their total balancing time from the early to late testing sessions. Transfer data from the late testing session revealed that all participants performed better with vision regardless of their practice condition. This suggests that vision is the dominant source of afferent information for this task and learning was not specific to the source of information available during practice. Thus, the specificity of practice hypothesis does not apply to this type of task

Stencils and problem partitionings: Their influence on the performance of multiple processor systems

Given a discretization stencil, partitioning the problem domain is an important first step for the efficient solution of partial differential equations on multiple processor systems. Partitions are derived that minimize interprocessor communication when the number of processors is known a priori and each domain partition is assigned to a different processor. This partitioning technique uses the stencil structure to select appropriate partition shapes. For square problem domains, it is shown that non-standard partitions (e.g., hexagons) are frequently preferable to the standard square partitions for a variety of commonly used stencils. This investigation is concluded with a formalization of the relationship between partition shape, stencil structure, and architecture, allowing selection of optimal partitions for a variety of parallel systems

The role of gender in the processing of dating scripts

The issues under investigation were gender differences in either content or memory discrimination of dating scripts and general examination for differences in memory of typical and atypical events using the script pointer plus tag (SP+T) hypothesis. A total of 52 female and 54 male undergraduates participated. Subjects were enrolled in introductory psychology classes at a large midwest university and were primarily Caucasian, single, and between the ages of 18-21 years. In Phase 1 and Phase 2 of the study, items that would possibly occur in 4 different dating scenarios were generated and then rated for typicality. Males and females both generated and rated items similarly in the first 2 phases. In Phase 3, the taped dating stories were presented along with a single-item recognition test which included many of these typical and atypical events. Analyses showed that memory discrimination varied significantly with gender, F(1, 51) = 4.07, p \u3c .05, and typicality, F(1, 51) = 395.80, p \u3c .0001, and a significant gender x typicality interaction was found, F(1, 51) = 7.17, p \u3c .01. Females displayed better memory discrimination overall, especially on atypical items. It was concluded that further investigation on possible gender differences in role, meaning, attention, and social norm affectation of dating scripts may explain differences in memory discrimination

Dipoles in Graphene Have Infinitely Many Bound States

We show that in graphene charge distributions with non-vanishing dipole moment have infinitely many bound states. The corresponding eigenvalues accumulate at the edges of the gap faster than any power

The Forced Non-Linear Schroedinger Equation with a Potential on the Half-Line

In this paper we prove that the initial-boundary value problem for the forced non-linear Schroedinger equation with a potential on the half-line is locally and (under stronger conditions) globally well posed, i.e. that there is a unique solution that depends continuously on the force at the boundary and on the initial data. We allow for a large class of unbounded potentials. Actually, for local solutions we have no restriction on the grow at infinity of the positive part of the potential, and for global solutions very mild assumptions that allow, for example, for exponential grow.Comment: 23 page

Older people maintaining mental health well-being through resilience : an appreciative inquiry study in four countries

Aim. To explore the experience and strategies of mental health well-being through resilience in older people across the four participating countries. Background. While there is increasing evidence of the way older people maintain physical well-being, there has not been the same emphasis when examining the ways in which older people enhance their resilience and so promote mental health well-being. Design. An Appreciative Inquiry approach was used. Method. A convenience sample of 58 people over the age of 65 years from Australia, UK, Germany, and South Africa were interviewed. Data were analysed using thematic analysis. Results. Participants described their experiences of mental health well-being in relation to: social isolation and loneliness; social worth; self-determination; and security. Strategies utilised include promoting resilience by maintaining community connections and relationships, keeping active, and emotional, practical and spiritual coping. Conclusion. The findings highlight the importance of maintaining mental health well-being through resilience. Although there were some variations between countries, these strategies for maintaining well-being transcended culture and nation. Relevance to clinical practice. Listening to older people through research such as the current study will help to determine what help is needed and how healthcare and policy makers can assist

Decision-making Techniques for Community Groups

Community groups often have a problem coming to a decision about projects to undertake. Quite often, resources, both human and financial, are limited; the number of problems seem overwhelming; or there are forceful advocates of a "pet" project. How can a group overcome these difficulties? The four decision-making techniques shown in this guide will make the task easier. The first two techniques generate ideas about community goals or projects while the last two prioritize the alternatives you have identified.New 6/92/5M

Town Meetings that Work

Town meetings -- The nature of community -- Orgainizing a town meeting -- The town meeting process -- Final thoughts -- AppendiciesNew 4/93/lM.Includes bibliographical reference

Olfactory lures in predator control do not increase predation risk to birds in areas of conservation concern

Context. Lethal control of predators is often undertaken to protect species of conservation concern. Traps are frequently baited to increase capture efficacy, but baited traps can potentially increase predation risk by attracting predators to protected areas. This is especially important if targeted predators can escape capture due to low trap success. Snake traps using live mouse lures may be beneficial if traps effectively remove snakes in the presence of birds and do not attract additional snakes to the area. Aims. The present study evaluated whether mouse-lure traps in areas occupied by birds (simulated by deploying birdlure traps) could influence predation risk from an invasive snake on Guam. Methods. Snake traps were used, with Japanese quail (Coturnix japonica) as a proxy for predation risk, to assess if an adjacent trap with a mouse (Mus musculus) would attract brown treesnakes (Boiga irregularis) to a focal area and increase contact between an invasive snake and avian prey. Catch per unit effort (CPUE) at stations containing either a bird-lure trap, mouse-lure trap or pair of traps (i.e. one bird-lure and one mouse-lure trap) was evaluated. Key results. Bird-lure traps paired with mouse-lure traps did not differ in CPUE from isolated bird-lure traps. At paired stations, CPUE of snakes in mouse-lure traps was 2.3_higher than bird-lure traps, suggesting mouse lures were capable of drawing snakes away from avian prey. Bird-lure traps at paired stations experienced a decay in captures over time, whereas CPUE for isolated bird-lure traps increased after 9 weeks and exceeded mouse-lure traps after 7 weeks. Conclusions. Mouse lures did not increase the risk of snakes being captured in bird-lure traps. Instead, mouse-lure traps may have locally suppressed snakes, whereas stations without mouse-lure traps still had snakes in the focal area, putting avian prey at greater risk. However, snakes caught with bird lures tended to be larger and in better body condition, suggesting preference for avian prey over mammalian prey in larger snakes. Implications. Strategic placement of olfactory traps within areas of conservatio

Pseudospectra in non-Hermitian quantum mechanics

We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis properties of eigenfunctions. The abstract results are illustrated by unexpected wild properties of operators familiar from PT-symmetric quantum mechanics.Comment: version accepted for publication in J. Math. Phys.: criterion excluding basis property (Proposition 6) added, unbounded time-evolution discussed, new reference