752 research outputs found
A local Fock-exchange potential in Kohn–Sham equations
We derive and employ a local potential to represent the Fock exchange operator in electronic single-particle equations. This local Fock-exchange (LFX) potential is very similar to the exact exchange (EXX) potential in density functional theory (DFT). The practical software implementation of the two potentials (LFX and EXX) yields robust and accurate results for a variety of systems (semiconductors, transition metal oxides) where Hartree–Fock and popular approximations of DFT typically fail. This includes examples traditionally considered qualitatively inaccessible to calculations that omit correlation
Contact Force and Scanning Velocity during Active Roughness Perception
Haptic perception is bidirectionally related to exploratory movements, which means that exploration influences perception, but perception also influences exploration. We can optimize or change exploratory movements according to the perception and/or the task, consciously or unconsciously. This paper presents a psychophysical experiment on active roughness perception to investigate movement changes as the haptic task changes. Exerted normal force and scanning velocity are measured in different perceptual tasks (discrimination or identification) using rough and smooth stimuli. The results show that humans use a greater variation in contact force for the smooth stimuli than for the rough stimuli. Moreover, they use higher scanning velocities and shorter break times between stimuli in the discrimination task than in the identification task. Thus, in roughness perception humans spontaneously use different strategies that seem effective for the perceptual task and the stimuli. A control task, in which the participants just explore the stimuli without any perceptual objective, shows that humans use a smaller contact force and a lower scanning velocity for the rough stimuli than for the smooth stimuli. Possibly, these strategies are related to aversiveness while exploring stimuli
The Experiences of Staff Who Support People with Intellectual Disability on Issues About Death, Dying, and Bereavement:a metasynthesis
Background: Historically, people with intellectual disabilities have tended to be excluded from knowing about death, dying, and bereavement. Staff in intellectual disability services can play a valuable role in improving understanding of these issues in those they support. This qualitative metasynthesis aimed to understand the experiences of staff supporting adults with intellectual disabilities with issues of death, dying, and bereavement. Method: Thirteen papers were identified following a systematic review of six databases. Results: Three themes were developed following a lines-of-argument synthesis: (1) Talking about death is hard: Negotiating the uncertainty in death, dying, and bereavement; (2) The commitment to promoting a “good death”; and (3) The grief behind the professional mask. “A cautious silence: The taboo of death,” was an overarching theme. Conclusions: A more open culture around issues of death, dying, and bereavement in intellectual disability settings is essential and could be promoted through staff training and support
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Listening to the experts: person-centred approaches to supporting autistic people and people with an intellectual disability in the mental health system
Summary
Despite numerous UK government policies aimed at reducing the number of autistic people and people with an intellectual disability in mental health hospitals, little progress has been made, with many experiencing lengthy stays that offer little therapeutic benefit. Once admitted, people are at risk of restrictive interventions and significantly delayed discharge, resulting in trauma. This article draws on the cases of four people to illustrate the limitations of current mental health system approaches to the challenges experienced by autistic people and people with an intellectual disability. The importance of relational working and listening to people is explored, and we demonstrate how this can facilitate the provision of bespoke housing and care packages to enable a successful return to life in the community. Finally, we offer recommendations on the changes urgently needed to ensure that autistic people and people with an intellectual disability can live ordinary lives in their own homes, with timely and effective support from mental health services when needed, just like everyone else
Do Empowered Front-Line Employees Perform Better? A Non-linear Approach and the Role of Service Complexity
This study re-examines the influence of front-line service employee empowerment on their performance, following a non-linear approach and integrating the role of service complexity. For that purpose, data were collected through a quantitative survey on 240 front-line employees in two major UK cities (London, Leeds). The study’s results indicate that empowerment has a significant impact on their performance and that this impact is non-linear (quadratic). Specifically, the relationship between empowerment and performance is negative for low-level empowerment and positive for high-level empowerment. In addition, the study’s results show that the nature of this relationship is different for different levels of service complexity. Specifically, for low-complexity services, the relationship between empowerment and performance was found quadratic, whereas for high-complexity services the relationship was found positive and linear. Based on the study’s main conclusions important implications for both academics and practitioners are presented
Failure analysis method for enhancing circularity through systems perspective
Recently, a circular economy has attracted global attention as an approach for addressing material security and resource-efficiency issues. As our societies shift toward a circular economy, manufacturers need to not only produce environmentally conscious products but to also realize reliable systems that will ensure the closure of the loops of the products, components, and materials. To do so, early-stage design is crucial to effectively and efficiently detect possible failures and then take adequate countermeasures against them. Although a few methods of failure analysis have been proposed to address environmental issues, these methods have failed to consider the cause–effect relationships among failures. This will hinder manufacturers from identifying core problems that should be addressed in a given system. Therefore, this study extends failure mode and effect analysis, which is an engineering technique used to address potential failures, by addressing the entire system reliability in relation to circularity. As a result of a case study of a manufacturer aiming to increase circularity with their products on the market, we revealed that the proposed method is useful in the early stage of design to (a) identify failure modes where effects are largely given to or received from other failures, (b) develop countermeasures effectively by addressing root causes of failures, and (c) find an opportunity to collaborate with external actors
Cellular Basis for Response Diversity in the Olfactory Periphery
An emerging idea in olfaction is that temporal coding of odor specificity can be intrinsic to the primary olfactory receptor neurons (ORNs). As a first step towards understanding whether lobster ORNs are capable of generating odor-specific temporal activity and what mechanisms underlie any such heterogeneity in discharge pattern, we characterized different patterns of activity in lobster ORNs individually and ensemble using patch-clamp recording and calcium imaging. We demonstrate that lobster ORNs show tonic excitation, tonic inhibition, phaso-tonic excitation, and bursting, and that these patterns are faithfully reflected in the calcium signal. We then demonstrate that the various dynamic patterns of response are inherent in the cells, and that this inherent heterogeneity is largely determined by heterogeneity in the underlying intrinsic conductances
Skin tribology: Science friction?
The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is frequently one of the interacting surfaces in relative motion. People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch. The question of course rises whether or not a trained tribologist would make different choices based upon a science based strategy? In other words: Is skin friction part of the larger knowledge base that has been generated during the last decades by tribology research groups and which could be referred to as Science Friction? This paper discusses the specific nature of tribological systems that include the human skin and argues that the living nature of skin limits the use of conventional methods. Skin tribology requires in vivo, subject and anatomical location specific test methods. Current predictive friction models can only partially be applied to predict in vivo skin friction. The reason for this is found in limited understanding of the contact mechanics at the asperity level of product-skin interactions. A recently developed model gives the building blocks for enhanced understanding of friction at the micro scale. Only largely simplified power law based equations are currently available as general engineering tools. Finally, the need for friction control is illustrated by elaborating on the role of skin friction on discomfort and comfort. Surface texturing and polymer brush coatings are promising directions as they provide way and means to tailor friction in sliding contacts without the need of major changes to the produc
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