169 research outputs found

    The Virtual Driver: Integrating Physical and Cognitive Human Models to Simulate Driving with a Secondary In-Vehicle Task.

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    Models of human behavior provide insight into people’s choices and actions and form the basis of engineering tools for predicting performance and improving interface design. Most human models are either cognitive, focusing on the information processing underlying the decisions made when performing a task, or physical, representing postures and motions used to perform the task. In general, cognitive models contain a highly simplified representation of the physical aspects of a task and are best suited for analysis of tasks with only minor motor components. Physical models require a person experienced with the task and the software to enter detailed information about how and when movements should be made, a process that can be costly, time consuming, and inaccurate. Many tasks have both cognitive and physical components, which may interact in ways that could not be predicted using a cognitive or physical model alone. This research proposes a solution by combining a cognitive model, the Queuing Network – Model Human Processor, and a physical model, the Human Motion Simulation (HUMOSIM) Framework, to produce an integrated cognitive-physical human model that makes it possible to study complex human-machine interactions. The physical task environment is defined using the HUMOSIM Framework, which communicates relevant information such as movement times and difficulty to the QN-MHP. Action choice and movement sequencing are performed in the QN-MHP. The integrated model’s more natural movements, generated by motor commands from the QN-MHP, and more realistic cognitive decisions, made using physical information from the Framework, make it useful for evaluating different designs for tasks, spaces, systems, and jobs. The Virtual Driver is the application of the integrated model to driving with an in-vehicle task. A driving simulator experiment was used to tune and evaluate the integrated model. Increasing the visual and physical difficulty of the in-vehicle task affected the resource-sharing strategies drivers used and resulted in deterioration in driving and in-vehicle task performance, especially for shorter drivers. The Virtual Driver replicates basic driving, in-vehicle task, and resource-sharing behaviors and provides a new way to study driver distraction. The model has applicability to interface design and predictions about staffing requirements and performance.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75847/1/hjaf_1.pd

    Glance strategies for using an in-vehicle touch-screen monitor

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    In this study, subjects in a driving simulator followed a lead vehicle that continuously changed speed while they also performed a secondary task on a touch-screen monitor that could be located at various positions within the simulator. Subjects were instructed to give priority to the following task. Driving performance in the following task was affected by whether or not the secondary task was required, but was not affected by the location of the monitor. However, consistent with the instructions about priority of tasks, time to complete the secondary task was strongly influenced by monitor position. Farther locations required more time, especially for shorter subjects. Analysis of the number and timing of glances away from the road suggested that subjects coped with the more difficult monitor positions primarily by making more glances to the monitor, while the average duration of individual glances was not much affected. These results suggest that the subjects’ partial success in coping with the secondary task was possible because the secondary task could be broken down into partially independent subtasks. This study was part of a modeling effort designed to better understand the combined visual and motor demands of secondary tasks, and how they are affected by the design of controls and displays. Various ways in which this study should be extended to support that modeling effort are reviewed.Industry Affiliation Program for Human Factors in Transportation Safety, Michigan University, Ann Arborhttp://deepblue.lib.umich.edu/bitstream/2027.42/62469/1/102283.pd

    Formality and informality in the summative assessment of motor vehicle apprentices: a case study

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    This article explores the interaction of formal and informal attributes of competence‐based assessment. Specifically, it presents evidence from a small qualitative case study of summative assessment practices for competence‐based qualifications within apprenticeships in the motor industry in England. The data are analysed through applying an adaptation of a framework for exploring the interplay of formality and informality in learning. This analysis reveals informal mentoring as a significant element which influences not only the process of assessment, but also its outcomes. We offer different possible interpretations of the data and their analysis, and conclude that, whichever interpretation is adopted, there appears to be a need for greater capacity‐building for assessors at a local level. This could acknowledge a more holistic role for assessors; recognise the importance of assessors’ informal practices in the formal retention and achievement of apprentices; and enhance awareness of inequalities that may be reinforced by both informal and formal attributes of assessment practices

    Why do we need (another) special issue on gender and VET?

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    The Journal of Vocational Education and Training last had a special issue on gender and vocational education and training (VET) in 2006. In the intervening 8 years, the journal has published 264 research papers, of which just 10 - that is, less than 4% - addressed the issue of gender in any substantive way. This is something of a disappointment, as editors always hope that a special issue will provoke increased discussion and debate in the journal about its theme as well as providing a focused resource. Is the problem that, compared to the effects of global labour migration flows, constantly rising youth unemployment figures or emerging skills gaps in an aging society, gender issues have lost their relevance as just one category of social inequalities among many others? This can hardly be the case, since it is obviously a most thorough-going and persistent one. Despite over 30 years of gender studies, and numerous policy initiatives to address gender inequalities, gender segregation persists in VET as well as in the labour market. Women still earn less, hold the majority of part-time contracts, tend to be stereotyped into caring and personal service work, and are largely under-represented in leadership positions. Is the problem then that there is nothing new to be said about gender and VET? We do not agree that that is the case either: gender injustice remains a central issue in VET and the labour market; and as the social, political and economic landscape changes rapidly in today's world, it is inevitable that gender inequalities are produced and reproduced in new and different ways. So we felt the need to call once again for a collection of papers dedicated specifically to this topic, and one that would reflect this evolution

    A two-year participatory intervention project with owners to reduce lameness and limb abnormalities in working horses in Jaipur, India

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    Participatory methods are increasingly used in international human development, but scientific evaluation of their efficacy versus a control group is rare. Working horses support families in impoverished communities. Lameness and limb abnormalities are highly prevalent in these animals and a cause for welfare concern. We aimed to stimulate and evaluate improvements in lameness and limb abnormalities in horses whose owners took part in a 2-year participatory intervention project to reduce lameness (PI) versus a control group (C) in Jaipur, India.In total, 439 owners of 862 horses participated in the study. PI group owners from 21 communities were encouraged to meet regularly to discuss management and work practices influencing lameness and poor welfare and to track their own progress in improving these. Lameness examinations (41 parameters) were conducted at the start of the study (Baseline), and after 1 year and 2 years. Results were compared with control horses from a further 21 communities outside the intervention. Of the 149 horses assessed on all three occasions, PI horses showed significantly (P<0.05) greater improvement than C horses in 20 parameters, most notably overall lameness score, measures of sole pain and range of movement on limb flexion. Control horses showed slight but significantly greater improvements in four parameters, including frog quality in fore and hindlimbs.This participatory intervention succeeded in improving lameness and some limb abnormalities in working horses, by encouraging changes in management and work practices which were feasible within owners’ socioeconomic and environmental constraints. Demonstration of the potentially sustainable improvements achieved here should encourage further development of participatory intervention approaches to benefit humans and animals in other contexts

    Phospholemman Phosphorylation Regulates Vascular Tone, Blood Pressure, and Hypertension in Mice and Humans

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    Background: While it has long been recognized that smooth muscle Na/K ATPase (NKA) modulates vascular tone and blood pressure (BP), the role of its accessory protein phopholemman (PLM) has not been characterized. The aim of this study was to test the hypothesis that PLM phosphorylation regulates vascular tone in vitro and this mechanism plays an important role in modulation of vascular function and BP in experimental models in vivo and in man. Methods: Mouse studies: PLM knock-in mice (PLM3SA), in which PLM is rendered unphosphorylatable, were used to assess the role of PLM phosphorylation in vitro in aortic and mesenteric vessels using wire myography and membrane potential measurements. In vivo BP and regional blood flow were assessed using Doppler flow and telemetry in young (14-16 weeks) and old (57-60 weeks) wild-type (WT) and transgenic mice. Human studies: We searched human genomic databases for mutations in PLM in the region of the phosphorylation sites and performed analyses within two human data cohorts (UK Biobank and GoDARTS) to assess the impact of an identified SNP on BP. This SNP was expressed in HEK cells and its effect on PLM phosphorylation determined using Western Blotting. Results: PLM phosphorylation at Ser63 and Ser68 limited vascular constriction in response to phenylephrine. This effect was blocked by ouabain. Prevention of PLM phosphorylation in the PLM3SA mouse profoundly enhanced vascular responses to PE both in vitro and in vivo. In ageing WT mice PLM was hypophosphorylated and this correlated with the development of ageing-induced essential hypertension. In man we identified a non-synonymous coding variant, single nucleotide polymorphism rs61753924, which causes the substitution R70C in PLM. In HEK cells the R70C mutation prevented PLM phosphorylation at Ser68. This variant's rare allele is significantly associated with increased BP in middle-aged men. Conclusions: These studies demonstrate the importance of PLM phosphorylation in the regulation of vascular tone and BP and suggest a novel mechanism, and therapeutic target, for ageing-induced essential hypertension in man

    Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'.

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    Innate immune cells must be able to distinguish between direct binding to microbes and detection of components shed from the surface of microbes located at a distance. Dectin-1 (also known as CLEC7A) is a pattern-recognition receptor expressed by myeloid phagocytes (macrophages, dendritic cells and neutrophils) that detects β-glucans in fungal cell walls and triggers direct cellular antimicrobial activity, including phagocytosis and production of reactive oxygen species (ROS). In contrast to inflammatory responses stimulated upon detection of soluble ligands by other pattern-recognition receptors, such as Toll-like receptors (TLRs), these responses are only useful when a cell comes into direct contact with a microbe and must not be spuriously activated by soluble stimuli. In this study we show that, despite its ability to bind both soluble and particulate β-glucan polymers, Dectin-1 signalling is only activated by particulate β-glucans, which cluster the receptor in synapse-like structures from which regulatory tyrosine phosphatases CD45 and CD148 (also known as PTPRC and PTPRJ, respectively) are excluded (Supplementary Fig. 1). The 'phagocytic synapse' now provides a model mechanism by which innate immune receptors can distinguish direct microbial contact from detection of microbes at a distance, thereby initiating direct cellular antimicrobial responses only when they are required

    Does proactive personality matter in leadership transitions? Effects of proactive personality on new leader identification and responses to new leaders and their change agendas

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    Despite the growing frequency of leadership transitions and their significant impact on team and organizational performance, little research has examined why and how teams develop an identification with a new leader or their subsequent receptiveness to the new leader’s change initiatives. Drawing from the contrast and congruence effects and the theoretical perspectives of leader identification, this study empirically tests a model in which the congruence of new leaders’ and their teams’ proactive personalities foster new leader identification, as well as the team’s behavioral responses to the new leader’s change agenda. This effect is strongest when the new leader’s proactive personality is higher than that of the former leader’s proactive personality (positive contrast). Our findings of a four-wave “before-and-after” transition survey of 155 hotel employees and 51 new leaders, achieved through polynomial regression analyses, proved very insightful. Essentially, we found that the congruence between a new leader’s and his/her team’s proactive personalities and the positive contrast between a former leader’s and the new leader’s proactive personalities enhanced new leader identification and the team’s shared identification with the new leader’s change agenda, and, thereby led the team to exhibit more behavioral engagement with, and voice behavior about, the new leader’s change agenda

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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