Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
206,041
result(s) for
"Applied physiology"
Sort by:
Where does an object trigger an action? An investigation about affordances in space
A series of experiments provide evidence that affordances rely not only on the mutual appropriateness of the features of an object and the abilities of an individual, but also on the fact that those features fall within her own reachable space, thus being really ready-to-her-own-hand. We used a spatial alignment effect paradigm and systematically examined this effect when the visually presented object was located either within or outside the peripersonal space of the participants, both from a metric (Experiment 1) and from a functional point of view (Experiment 2). We found that objectual features evoke actions only when the object is presented within the portion of the peripersonal space that is effectively reachable by the participants. Experiments 3 and 4 ruled out that our results could be merely accounted for by differences in the visual salience of the presented objects. Our data suggest that the power of an object to automatically trigger an action is strictly linked to the effective possibility that an individual has to interact with it.
Journal Article
Somatoparaphrenia: a body delusion. A review of the neuropsychological literature
A review of published brain-damaged patients showing delusional beliefs concerning the contralesional side of the body (somatoparaphrenia) is presented. Somatoparaphrenia has been reported, with a few exceptions, in right-brain-damaged patients, with motor and somatosensory deficits, and the syndrome of unilateral spatial neglect. Somatoparaphrenia, most often characterized by a delusion of disownership of left-sided body parts, may however occur without associated anosognosia for motor deficits, and personal neglect. Also somatosensory deficits may not be a core pathological mechanism of somatoparaphrenia, and visual field disorders may be absent. Deficits of proprioception, however, may play a relevant role. Somatoparaphrenia is often brought about by extensive right-sided lesions, but patients with posterior (parietal-temporal), and insular damage are on record, as well as a few patients with subcortical lesions. Possible pathological factors include a deranged representation of the body concerned with ownership, mainly right-hemisphere-based, and deficits of multisensory integration. Finally, the rubber hand illusion, that brings about a bodily misattribution in neurologically unimpaired participants, as somatoparaphrenia does in brain-damaged patients, is briefly discussed.
Journal Article
Instantaneous changes in heart rate regulation due to mental load in simulated office work
The cardiac regulation effects of a mental task added to regular office work are described. More insight into the time evolution during the different tasks is created by using time–frequency analysis (TFA). Continuous wavelet transformation was applied to create time series of instantaneous power and frequency in specified frequency bands (LF 0.04–0.15 Hz; HF 0.15–0.4 Hz), in addition to the traditional linear heart rate variability (HRV) parameters. In a laboratory environment, 43 subjects underwent a protocol with three active conditions: a clicking task with low mental load and a clicking task with high mental load (mental arithmetic) performed twice, each followed by a rest condition. The heart rate and measures related to vagal modulation could differentiate the active conditions from the rest condition, meaning that HRV is sensitive to any change in mental or physical state. Differences between physical and mental stress were observed and a higher load in the combined task was observed. Mental stress decreased HF power and caused a shift toward a higher instantaneous frequency in the HF band. TFA revealed habituation to the mental load within the task (after 3 min) and between the two tasks with mental load. In conclusion, the use of TFA in this type of analysis is important as it reveals extra information. The addition of a mental load to a physical task elicited further effect on HRV parameters related to autonomic cardiac modulation.
Journal Article
Quality Management and Job Quality: How the ISO 9001 Standard for Quality Management Systems Affects Employees and Employers
Several studies have examined how the ISO 9001 quality management systems standard predicts changes in organizational outcomes such as profits. This is the first large-scale study to explore how employee outcomes such as employment, earnings, and health and safety change when employers adopt ISO 9001. We analyzed a matched sample of nearly 1,000 companies in California. ISO 9001 adopters subsequently had far lower organizational death rates than a matched control group of nonadopters. Among surviving employers, ISO adopters had higher growth rates for sales, employment, payroll, and average annual earnings. Injury rates declined slightly for ISO 9001 adopters, although total injury costs did not. These results have implications for organizational theory, managers, and public policy.
Journal Article
Placing order in space: the SNARC effect in serial learning
The SNARC effect, consisting of a systematic association between numbers and lateralized response, reflects the mental representation of magnitude along a left-to-right mental number line (Dehaene et al. in J Exp Psychol 122:371-396, 1993). Critically, this effect has been reported in the classification of overlearned non-numerical sequences such as letters, days and months (Gevers et al. in Cognition 87:B87-B95, 2003 and Cortex 40:171-172, 2004) suggesting that ordinal, rather than magnitude information, is critical for spatial coding. This study tests the hypothesis of an oriented spatial representation as the privileged way of mentally organizing serial information, by looking for stimulus-response compatibility effects in the processing of a newly acquired arbitrary sequence. Here we report an association between ordinal position of the items and spatial response preference for both order-relevant and order-irrelevant tasks. These results suggest that any ordered information, even when order is not intrinsically relevant to it, is spontaneously mapped in the representational space. This spatial representation is likely to acquire a left-to-right orientation, at least in western cultures.
Journal Article
An object for an action, the same object for other actions: effects on hand shaping
Objects can be grasped in several ways due to their physical properties, the context surrounding the object, and the goal of the grasping agent. The aim of the present study was to investigate whether the prior-to-contact grasping kinematics of the same object vary as a result of different goals of the person grasping it. Subjects were requested to reach toward and grasp a bottle filled with water, and then complete one of the following tasks: (1) Grasp it without performing any subsequent action; (2) Lift and throw it; (3) Pour the water into a container; (4) Place it accurately on a target area; (5) Pass it to another person. We measured the angular excursions at both metacarpal-phalangeal (
mcp
) and proximal interphalangeal (
pip
) joints of all digits, and abduction angles of adjacent digit pairs by means of resistive sensors embedded in a glove. The results showed that the presence and the nature of the task to be performed following grasping affect the positioning of the fingers during the reaching phase. We contend that a one-to-one association between a sensory stimulus and a motor response does not capture all the aspects involved in grasping. The theoretical approach within which we frame our discussion considers internal models of anticipatory control which may provide a suitable explanation of our results.
Journal Article
A three-compartment muscle fatigue model accurately predicts joint-specific maximum endurance times for sustained isometric tasks
The development of localized muscle fatigue has classically been described by the nonlinear intensity–endurance time (ET) curve (Rohmert, 1960; El Ahrache et al., 2006). These empirical intensity–ET relationships have been well-documented and vary between joint regions. We previously proposed a three-compartment biophysical fatigue model, consisting of compartments (i.e. states) for active (MA), fatigued (MF), and resting (MR) muscles, to predict the decay and recovery of muscle force (Xia and Frey Law, 2008). The purpose of this investigation was to determine optimal model parameter values, fatigue (F) and recovery (R), which define the “flow rate” between muscle states and to evaluate the model's accuracy for estimating expected intensity–ET curves. Using a grid-search approach with modified Monte Carlo simulations, over 1 million F and R permutations were used to predict the maximum ET for sustained isometric tasks at 9 intensities ranging from 10% to 90% of maximum in 10% increments (over 9 million simulations total). Optimal F and R values ranged from 0.00589 (Fankle) and 0.0182 (Rankle) to 0.00058 (Fshoulder) and 0.00168 (Rshoulder), reproducing the intensity–ET curves with low mean RMS errors: shoulder (2.7s), hand/grip (5.6s), knee (6.7s), trunk (9.3s), elbow (9.9s), and ankle (11.2s). Testing the model at different task intensities (15–95% maximum in 10% increments) produced slightly higher errors, but largely within the 95% prediction intervals expected for the intensity–ET curves. We conclude that this three-compartment fatigue model can be used to accurately represent joint-specific intensity–ET curves, which may be useful for ergonomic analyses and/or digital human modeling applications.
Journal Article
Space perception and body morphology: extent of near space scales with arm length
Numerous studies have found that the near space immediately surrounding the body is represented differently than more distant space. In a previous study, we found a gradual shift in attentional bias (on a line bisection task) between near and far space (Longo and Lourenco in Neuropsychologia 44:977-981, 2006). The present study concerns the possibility that arm length relates systematically to the rate at which this gradual shift between near and far space occurs. Participants bisected lines using a laser pointer at eight distances (within and beyond arm's reach), and the rate of shift was estimated by the slope of the least-squares regression line. A negative correlation was found between the slopes and arm length; participants with longer arms showed a more gradual shift in bias with increasing distance than those with shorter arms. These results suggest that, while near space cannot be considered categorically as that within arm's reach, there is a systematic relation between the extent (\"size\") of near space and arm length. Arm length may constitute an intrinsic metric for the representation of near space.
Journal Article
Arousal, valence and their relative effects on postural control
There is mounting evidence to suggest that emotional state can influence postural control. Emotions are often qualified using dimensions such as valence (pleasantness) and arousal. While affective pictures have been used to detail the effects of valence on postural control, the influence of arousal independently, or in combination with valence, has yet to be investigated. This is an important oversight because there are multiple sensory and neuromuscular mechanisms that are known to be sensitive to arousal and to contribute to postural control. As such, the current study is the first to independently manipulate valence and arousal through affective pictures and to examine their independent effects on postural control. Subjects stood quietly for 90 s long blocks while watching affective pictures, grouped by normative ratings of arousal (high and low) and valence (pleasant and unpleasant), and during which centre of pressure (COP) and electrodermal activity (EDA) were collected. EDA and anterior–posterior COP frequency were both increased with arousal, but not by valence. The postural effects observed in this study parallel those typically seen in other highly arousing situations, such as standing at the edge of an elevated platform or during performance evaluation. Therefore, we argue that arousal is a mediator of postural control and should be considered as a potential confound when testing or diagnosing subjects in clinical or experimental settings.
Journal Article