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Results for “Task Shifting”

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PubMed1984

Changes in nurses' blood pressure and heart rate while communicating.

Cardiovascular responses of nurses were measured during two communication tasks. In the first experiment 40 nurses' blood pressures and heart rates were taken pre, during, and post change-of-shift report. In the second experiment, 30 nurses spoke to an individual nurse and to a group of nurses. Blood pressures and heart rates were recorded pre, during, and post speech in both conditions. Analyses of variances showed that speaking levels of all cardiovascular parameters were higher (p less than .001) than resting levels in both experiments. Blood pressures and heart rates were higher (p less than .0001) in front of a group than in front of an individual. These findings extend previous work that has shown communication alters blood pressure.

Adult↗

PubMed1990

Effect of bilateral asymmetric tooth clenching on load distribution at the mandibular condyles.

The effects of balancing-side tooth contacts on temporomandibular joint loads are unclear. We used a 3-D computer model to calculate the magnitude and direction of temporomandibular reaction forces during simulated clenching on interocclusal acrylic resin shims and between natural teeth. Muscle tensions were proportioned according to the task modeled. Working-side tooth contacts included the canine alone, as well as group function, and occlusal loads were progressively shifted toward a posterior contralateral simple balancing contact. In the acrylic resin shim experiments, group function with simple balancing contact yielded the highest forces at the load point and at both temporomandibular joints. Movement of the occlusal load toward the balancing side produced greater, anteriorly oriented forces on the working condyle. For natural teeth, changes in the angle of resultant tooth force (simulating facet angulation) greatly influenced condylar forces. As the occlusal load moved toward the balancing side, greater and more laterally oriented forces were produced on the balancing condyle. Unilateral clenching on the canine produced the least condylar and bite forces. The simulation involving natural teeth offers a possible explanation for deviations in form and osteoarthrosis at the temporomandibular joints.

Acrylic Resins↗

PubMedDate not supplied

Area-specific self-regulation of slow cortical potentials on the sagittal midline and its effects on behavior.

Exteroceptive feedback was given for negative and positive shifts in slow potentials (SPs) recorded from Fz, Cz, or Pz (between groups design). Slow potentials at the feedback site were referred to adjacent scalp and non-cephalic electrodes, so as to confine SP shifts to the feedback location. Area-specific regulation of SPs was obtained at each midsagittal site after 3 days of feedback training. Subjects reported sensorimotor and emotional arousal when negative SP shifts were trained frontally, but not when negative shifts were trained parietally (cognitive/attentional strategies reported after parietal feedback). Area-specific regulation of SPs was subsequently abolished when behavioral tasks were added to further probe frontal/parietal differences (dual-task procedure). These findings indicate that area-specific self-regulation of SPs is possible on the sagittal midline, and that self-regulated parietal SPs (in contrast to frontal ones) arise from non-motoric generators. The source of SP self-regulation was more readily probed by verbal reports of feedback strategy than by study of dual-task relations, because feedback control was disrupted by the dual-task requirement.

Adult↗

PubMed2006

Small-scale spatial cognition in pigeons.

Roberts and Van Veldhuizen's [Roberts, W.A., Van Veldhuizen, N., 1985. Spatial memory in pigeons on the radial maze. J. Exp. Psychol.: Anim. Behav. Proc. 11, 241-260] study on pigeons in the radial maze sparked research on landmark use by pigeons in lab-based tasks as well as variants of the radial-maze task. Pigeons perform well on open-field versions of the radial maze, with feeders scattered on the laboratory floor. Pigeons can also be trained to search precisely for buried food. The search can be based on multiple landmarks, but is sometimes controlled by just one or two landmarks, with the preferred landmarks varying across individuals. Findings are similar in landmark-based searching on a computer monitor and on a lab floor, despite many differences between the two kinds of tasks. A number of general learning principles are found in landmark-based searching, such as cue competition, generalization and peak shift, and selective attention. Pigeons also learn the geometry of the environment in which they are searching. Neurophysiological studies have implicated the hippocampal formation (HF) in avian spatial cognition, with the right hippocampus hypothesized to play a more important role in the spatial recognition of goal locations. Most recently, single-cell recording from the pigeon's hippocampal formation has revealed cells with different properties from the classic 'place' cells of rats, as well as differences in the two sides of the hippocampus.

Animals↗

PubMed2004

The physical workload of nursing personnel: association with musculoskeletal discomfort.

Direct care-nursing personnel around the world report high numbers of work-related musculoskeletal disorders. This cross-sectional study examined the association between the performance of high-risk patient-handling tasks and self-reported musculoskeletal discomfort in 113 nursing staff members in a veterans' hospital within the United States. Sixty-two percent of subjects reported a 7-day prevalence of moderately severe musculoskeletal discomfort. There was a significant association between wrist and knee pain and the number of highest-risk patient-handling tasks performed per hour interacting with the load lifted. On units where lifting devices are readily available, musculoskeletal risk may have shifted to the wrist and knee.

Adult↗

PubMed2006

Relative contribution of the pressure variations under the feet and body weight distribution over both legs in the control of upright stance.

The resultant centre of pressure (CP(Res)) trajectories are aimed at controlling body movements in upright stance. When standing on two legs, these trajectories are generated by exerting reaction forces under each foot and by loading-unloading mechanisms intervening at the hip level. To assess the respective contribution of each of these factors in stance maintenance, a group of healthy individuals were tested in several conditions including standing quietly and voluntarily producing under each foot larger CP displacements in phase and in opposite phase along medio-lateral (ML) and antero-posterior (AP) axes. The results, based on the computation of coefficients of correlation between CP(Res) trajectories and various time series including the relative body weight applied to one leg and plantar CP trajectories, highlight some differences according to the axes along which the displacements take place and the amplitudes of the movements. Furthermore, the comparison of the CP(Res) trajectories resulting from each one of these two factors reveals the predominant role played by the loading-unloading mechanisms intervening at the hip level for the movements along the ML axis and those of the plantar CP displacements along the AP axis. Increasing the plantar CP displacements in phase or in opposite phase substantially modifies these contributions although without inferring a shift to the benefit of the other mechanism. The specific morphology of the ankle and hip joints implicated in this postural task plainly explains this postural control organisation. In particular, the link between the segmental configuration of the lower limbs and these mechanisms are discussed.

Adult↗

PubMed2003

Is perseveration caused by inhibition failure? Evidence from preschool children's inferences about word meanings.

Four studies examined the relation between children's cognitive inhibition and flexibility in a lexical inference task. Children's linguistic flexibility was assessed by the Flexible Induction of Meaning (FIM) test (Deák, 2000a), which requires that children shift inferences about the meanings of several words for novel objects. In Study 1, 54 3-year-olds either were trained between blocks of problems, for a delay of 3 min, or received no training or delay. Training delays did not influence perseveration. In Study 2 (N=72 3- and 4-year-olds') novel word problems were grouped either to increase the frequency of cue switches (i.e., reduce response "set") or minimize the interval between problems about the same objects. Again, no effect was found. In Study 3, 48 3- and 4-year-olds completed 6 preliminary trials; in a high interference group these trials generated a response set to be inhibited upon the first switch to a new cue context. This group did not perseverate more than a control group. There was no association between FIM perseveration and a Stroop-like test of verbal inhibition though both were marginally related to receptive vocabulary. In study 4 (48 3- and 4-year-olds), FIM was again unrelated to Stroop performance, but was related to the ability to tell whether a situation or problem is indeterminate. Thus, flexibility across semantic inferences is not influenced by timing, order, and number of pre-switch problems and is not predicted by individual differences in a test of verbal inhibition. However previously reported age and individual differences in flexible induction of word meanings are robust and related to vocabulary and logical ability.

Child, Preschool↗

PubMed2000

Functional brain imaging as a looking-glass into the degraded brain: reviewing evidence from Alzheimer disease in relation to normal aging.

Research on the real-time relationship between brain activity and mental performance is intense. However, relatively few studies have been devoted to patients with different diseases or lesions. Such studies may cast light on certain aspects of brain activity, such as plasticity. This review summarizes studies on Alzheimer's disease (AD) patients where the techniques to map brain activity in relation to mental performance have been utilized. Research findings suggest, that there is a spectrum of changes in AD patients that is distinct from that seen in healthy aging. These changes include: (i) loss of activated regions, (ii) reduced activation possibly due to brain degeneration typical of AD, (iii) the emergence of newly activated regions in order to compensate for minor brain deterioration (e.g., an enlargement of activated regions sometimes manifested as an increased bilaterality or a hemispheric shift of activation, and dedifferentiation), (iv) decreased level of activation, and (v) no change at all, which may occur in easy tasks or tasks that do not involve regions exposed to brain atrophy. In conclusion, the pattern of activation in AD depends on interactions between the clinical stage of patients, and the pattern of brain degeneration, as well as the task difficulty and specific networks necessary for solving the task.

Aged↗

PubMed1999

The role of motion in children's categorization of objects.

Perceptual cues play a fundamental role in early categorization of objects. What is meant by perceptual cues in the literature, however, is not always clear. It is fair to say that they are typically understood to be static shape cues. A number of recent studies have suggested that dynamic perceptual cues, such as motion, may also be important in early categorization. The study presented here explored the role that motion plays in children's categorization of animal and non-animal kinds, such as geometric figures. Motion was directly pitted against shape as a cue for categorization. Results showed that 4-year-old children, confronted with a choice between shape and motion, significantly used motion cues over shape cues to categorize objects, regardless of whether they were animals or geometric figures. Seven-year-olds also tended to use motion more often to categorize animals but not when dealing with geometric figures. Older children, who have been found to have a clearer natural kind/artifact distinction, seem to appreciate the uniqueness of movement to animals and see motion as more relevant to their categorization but relatively less so to categorize geometric figures. This developmental shift in the categorization of animals and geometric figures based on motion was further confirmed by testing adults on the same tasks. Adults were found to base their judgements significantly more often on motion for animals but not for geometric figures. These findings support the view that children are initially guided by motion in object categorization, suggesting that motion plays an overriding role that is central in the process of concept acquisition and in the mechanisms by which concepts are later structured.

Analysis of Variance↗

PubMedDate not supplied

Rodent navigation after dissociation of the allocentric and idiothetic representations of space.

Analysis of the neural mechanisms of place navigation requires isolation of the landmark dependent allocentric and self-motion related idiothetic orientation modes. To assess their importance, rats were trained on a rotating (360 degrees/min) arena to avoid foot shocks applied in either a room frame defined sector of the arena or an idiothetically defined region of the floor. Independence of the respective allocentric and idiothetic engrams was revealed by simultaneous avoidance of both locations. The possibility that idiothetic orientation was confounded by allocentric intramaze cues was examined in an apparatus consisting of an inner rotating disc surrounded by a stationary belt. As long as the rat was on the moving disc, position of the 60 degrees shock sector was stable on the disk but projected from it to different parts of the belt. When the rat moved to the belt the shock sector was now stable on the belt, but its projection to the disk travelled over its moving surface. The rat always found the shock sector in an idiothetically correct position but the mutual shifts of the disk and belt eliminated the utility of local cues like scent marks for the idiothetic solution of the task. Purely allocentric orientation was required in a place recognition task in which pressing a lever mounted on a rotating arena was rewarded only when the operandum moved through an allocentrically defined 60 degrees segment of its trajectory. Place recognition was manifest by increased bar pressing rates on approach to and inside the reward zone. These methods may reveal how hippocampal place cell activity correlates with both allocentric and idiothetic aspects of spatial orientation.

Animals↗

PubMed1998

Word repetition within- and across-visual fields: an event-related potential study.

A divided visual field (DVF) procedure was used to investigate the scalp distribution of the event-related potential (ERP) repetition effect. ERPs were recorded from 27 scalp sites whilst subjects (n = 20) discriminated between words and non-words presented to either the left (LVF) or the right (RVF) visual field. A proportion of the words were repeated on the trial immediately following their first presentation. In two within-field repetition conditions the two encounters with a word occurred in the same visual field (LVF or RVF). In two across-field repetition conditions, the two encounters with a word occurred in different visual fields. For both words and non-words, task performance was better for RVF presentations than for LVF presentations. In each repetition condition there was a positive-going shift in the ERP elicited by repeated words compared to that elicited by words on their first presentation. This ERP repetition effect was equivalent in magnitude and lateralised to the right hemisphere to an equivalent degree in all four repetition conditions. It is suggested that the ERP effects largely reflect the processing of visual form thought to occur predominately in the right hemisphere.

Adolescent↗

PubMed1997

The computation of orientation statistics from visual texture.

This paper examines how observers estimate the overall orientation of spatially disorganised textures containing variable orientation. Experiments used asymmetrical distributions of orientations to separate the predictions from different models of average orientation estimation. Stimuli were composed of two spatially intermingled sets of oriented patches, each set having Gaussian distributed element orientation. The threshold separation of the means of the two sets was determined for a variety of tasks. Discrimination of these textures from a reference composed of two sets with the same mean orientation was well predicted by discrimination of orientation variability. A single interval judgement of which set contained more elements required a greater separation of the set orientations and suggested that the sets must be resolved in the orientation domain for independent representation of their properties. That resolution is required to perform this task further suggests that orientational skew is not coded. Threshold offsets for judgement of average orientation were re-expressed as shifts of four candidate features for coding the central tendency of texel orientations. Comparison with similar thresholds for single distributions of orientations indicated that average orientation is assigned to the centroid of a set of orientation measures.

Discrimination, Psychological↗

PubMed2003

Bottom-up transfer of sensory-motor plasticity to recovery of spatial cognition: visuomotor adaptation and spatial neglect.

A large proportion of right-hemisphere stroke patients show hemispatial neglect, a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space, inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment. This spatial cognition disorder affects the orientation of behavior with a shift of proprioceptive representations toward the lesion side. This shift is similar to that produced by psychophysical manipulations as a wedge-prism exposure in normal healthy subjects. In both subjects, one major compensative effect of short-term prism adaptation is a shift of proprioceptive representations, demonstrated by a shift in manual straight-ahead pointing in the dark, in a direction opposite to the visual shift. In neglect patients, prism adaptation involves the shift of proprioceptive representations to the left with a reduction of rightward bias observed in neglect patients in visuo-manual tasks as line-bisection, line-cancellation or copy drawing. Improvement of neglect is also observed in no visuo-manual tasks as mental imagery, auditory extinction or posture. This generalization of prism adaptation effects at different neglect level symptoms suggests that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations. Moreover the positive effects found for both sensorimotor and more cognitive spatial functions lasted for at least two or more hours after prism removal. Unlike reduction of neglect through sensory stimulations, the long-lasting improvement of neglect after prism adaptation suggests the activation of short-term plasticity of brain functions related to coordinate transformations and space representations. Lastly, the duration of these effects could be useful in rehabilitation programs, as suggested by the effects of prism adaptation on disabling neglect symptoms as wheelchair driving, posture or writing.

Adaptation, Physiological↗

PubMed2003

A perspective on the analysis of credible commitment and myopia in health sector decision making.

This paper examines the role of credible commitment in facilitating long-term decision making in health care. Commitments are defined as an undertaking by one party to perform a certain task in the future.Policy objectives and political imperatives within public sector organisations can often mean that decision making takes place on shifting institutional terrain. This creates incentives on decision making that favours those choices that yield short-term gains. Such myopia is not necessarily consistent with organisational objectives and the implementation of policies that promote such objectives. These incentive problems can be formally modelled in terms of prisoners' dilemma and co-ordination games. Measures that promote public sector organisations to credibly commit to various values or policy positions can assist in reconciling individual and organisational objectives by allowing decision makers, in good faith, to build long-term outcomes into their decision making. In effect they allow co-operation and co-ordination. Given these potential gains, credible commitment can occur spontaneously but when not, may need to be facilitated by a third party (notably the State). Such forms of commitment are usually apparent in various policy measures such as health service constitutions, long-term contracting, legislation and incentive payments. Measures that secure credible commitment allow the discount rate to be reduced on long-term decisions of not only public sector organisations but also those stakeholders who rely on stable public sector institutions. However, the importance of the notion of commitment needs to be recognised against the background of other institutional factors that may influence decision making.

Decision Making, Organizational↗

PubMedDate not supplied

Component-based development for supporting workflows in hospitals.

Changing requirements for health care information systems force the development of an open, modular architecture in which components can be integrated. This offers a flexible means for integrating different (heterogeneous) systems used by different users. Selecting the components to integrate, and determining the 'right way' to integrate them, necessitates a shift in focus towards the business process to be supported. The realization of such an open, modular architecture is a difficult task. It consists of breaking down existing systems in required components and integrating these and other components. Many authors on component-based development strategies focus attention on the technological issues of component integration (do we use CORBA, DCOM/OLE, or EDI?). This paper presents an approach for determining the required components, and the way they have to be integrated, based on an analysis of the business process to be supported, and the information systems currently used.

Computer Communication Networks↗

PubMed1988

Asymmetric influence in mock jury deliberation: jurors' bias for leniency.

Investigators have frequently noted a leniency bias in mock jury research, in which deliberation appears to induce greater leniency in criminal mock jurors. One manifestation of this bias, the asymmetry effect, suggests that proacquittal factions are more influential than proconviction factions of comparable size. A meta-analysis indicated that these asymmetry effects are reliable across a variety of experimental contexts. Experiment 1 examined the possibility that the leniency bias is restricted to the typical college-student subject population. The decisions of college-student and community mock jurors in groups beginning deliberation with equal faction sizes (viz., 2:2) were compared. The magnitude of the asymmetry effect did not differ between the two populations. We hypothesized that the asymmetry effect was caused by an asymmetric prodefendant standard of proof--the reasonable-doubt standard. In Experiment 2, subjects received either reasonable-doubt or preponderance-of-evidence instructions. After providing initial verdict preferences, some subjects deliberated in groups composed with an initial 2:2 split, whereas other subjects privately generated arguments for each verdict option. A significant asymmetry was found for groups in the reasonable-doubt condition, but group verdicts were symmetrical under the preponderance-of-evidence instructions. Shifts toward leniency in individual verdict preferences occurred for group members, but not for subjects who performed the argument-generation task. The theoretical and applied significance of these findings is discussed.

Adolescent↗

PubMed2001

Spatial attention triggered by eye gaze increases and speeds up early visual activity.

What are the neuronal correlates of reflexive shifts of attention triggered by eye gaze direction? Event related potentials (ERPs) were measured on 14 subjects performing a spatial attention task where eye gaze direction of a face cued the location of a forthcoming target. Subjects were faster in detecting a validly cued target, i.e. one appearing at the location the eye was gazing at, compared to invalidly cued targets, despite the non-predictive value of the eye cues. ERP results showed an enhanced and earlier occipito-parietal P1 and N1 for valid trials, demonstrating the early modulation of visual input by attentional allocation. These findings provide the first evidence that social attention can rapidly modify the processing of visual information in extrastriate cortex.

Adult↗

PubMed1998

Human cortical mechanisms of visual attention during orienting and search.

Functional anatomical studies indicate that a set of neural signals in parietal and frontal cortex mediates the covert allocation of attention to visual locations across a wide variety of visual tasks. This frontoparietal network includes areas, such as the frontal eye field and supplementary eye field. This anatomical overlap suggests that shifts of attention to visual locations of objects recruit areas involved in oculomotor programming and execution. Finally, the fronto-parietal network may be the source of spatial attentional modulations in the ventral visual system during object recognition or discrimination.

Attention↗