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PubMed1995

Effect of valvular heart diseases, migraine headaches, and perianal diseases on the risk of involvement in motor vehicle crashes.

Impaired health can interfere with driving performance. We have launched this investigation to identify in professional military drivers health parameters that might be associated with involvement in motor vehicle crashes (MVCs). All Israel Defense Forces professional male drivers (N = 5,605) conscripted into compulsory military service between April 1, 1988 and April 1, 1990 were divided into two groups according to whether (N = 1,300) or not (N = 4,305) the driver was involved in MVCs during the same time frame. Using the multivariate Cox model, a significant association was shown between involvement in MVCs and the following health parameters: mild-to-moderate valvular heart disease (p = 0.0002, chi 2 = 13.89), migraine headaches (p = 0.009, chi 2 = 6.91), and perianal diseases (p = 0.006, chi 2 = 7.44). We hypothesize that interference with the driver's performance level may be a result of the discomfort associated with those clinical conditions. It is possible that interference with the personal performance level decreased the ability of the driver to cope with the specific driving task demands and resulted in the involvement of the driver in MVCs. We suggest that because of the high social and economic costs associated with road accidents, it is important to investigate further the association of involvement in MVCs and health problems. If our findings are confirmed in the future studies, intervention programs to reduce MVC rates would be suggested and conducted among professional drivers.

Accidents, Traffic↗

PubMed1997

Aerobic capacity and cognitive performance in a cross-sectional aging study.

In a population unselected for aerobic fitness status, aerobic fitness (VO2max) and its interaction with age were used to predict performance on several cognitive measures known to be affected by chronological age. It was hypothesized that, in particular, cognitively demanding tasks would be sensitive to aerobic capacity. Healthy subjects between 24 and 76 yr of age (N = 132) were recruited from a larger study into determinants of cognitive aging (Maastricht Aging Study-MAAS). All participants took part in a submaximal bicycle ergometer protocol and an extensive neurocognitive examination, including tests of intelligence, verbal memory, and simple and complex cognitive speed. Participants engaged more hours a week in aerobic sports and felt healthier than the nonparticipants of the same age did. No group differences were found in the basic anthropometric characteristics height, weight, and BMI. Two of four subtasks that reflect complex cognitive speed (Stroop color/word interference and Concept Shifting Test) showed main and interaction effects with age of aerobic capacity in a hierarchical regression analysis, accounting for up to 5% of variance in parameter score after correction for age, sex, and intelligence main effects. These findings fit well within a moderator model of aerobic fitness in cognitive aging. They add to the notion that aerobic fitness may selectively and age-dependently act on cognitive processes, in particular those that require relatively large attentional resources.

Adult↗

PubMed1988

A new test for screening color vision: concurrent validity and utility.

Recognizing the need for an effective test for screening color vision in young children, we have developed a new pseudoisochromatic (PIC) plate test which is useful for a wide variety of observers at different ages. The test consists of four plates and responses can be used to categorize color vision as normal or as either red-green or blue-yellow defective. Results of this validation study with adults, both color normal and red-green defective, show a high degree of correlation between the new test and the Nagel anomaloscope: there were no false positives and only a few false negatives, which occurred with mild deuteranomalous observers. The validity of the test compares favorably to the Ishihara, F-2, and the AO-HRR screening plates. Results with toddlers (3 to 6 years) indicate that the task demands of the test are well suited for testing young children. The percentage of color defectives identified in the toddler sample using the new test is closer to the adult prevalence than results obtained with the F-2 and AO-HRR screening plates, which gave dramatically higher failure rates. The new test is culture-free and can be administered rapidly to both verbal and nonverbal observers using pointing or preferential looking.

Adult↗

PubMed1993

An analysis of the role of vision anomalies in reading interference.

Several reviews of the literature have shown a relation between vision anomalies and reading problems. The studies have been correlational - comparative in nature and thus have not established causal relations. This paper suggests that before experimental studies are conducted to establish causation, studies of the process by which vision anomalies produce reading interference need to be conducted. The paper discusses the factors to consider in studying vision and reading interference. The factors are: nature of the vision anomaly, type and severity of symptoms produced, type of reading interference (perceptual or functional deficiency), amount and type of near task demands, reading skill, and reading development stage.

Adolescent↗

PubMed2001

Monovision: a review of the scientific literature.

We reviewed the scientific literature on monovision to compare the visual performance of monovision patients with that of others wearing more traditional prescriptions. We found that visual performance of monovision patients was comparable to that of control patients wearing a balanced binocular correction, provided that reading adds were not greater than about +2.5 D, that illumination was photopic, and that stimuli were presented at supra-threshold levels. Under these conditions, monovision patients were satisfied with their perceptual experience and performed within 2 to 6% of balanced binocular control patients on a range of occupational tasks. It is noteworthy that monovision patients had relatively more difficulty with acuity-based tasks than with tasks demanding good depth perception. With reading adds over +2.5 D, at low levels of illumination, or with near-threshold level stimuli, visual performance of monovision patients was reduced compared with controls. Subjectively, under low levels of illumination, monovision patients experienced problems with glare and halos around point sources of light.

Contact Lenses↗

PubMed1992

A triangular cutting arteriotomy scissors facilitating end-to-side anastomoses.

A new microsurgical triangular cutting scissors facilitating end-to-side anastomoses has been developed. The instrument removes oval pieces of tissue from the vascular wall with a single cut. This has several advantages over conventional double cuts with straight microscissors. Preferential use of end-to-side anastomoses has been advocated by several authors, one of the main reasons for this being preservation of the distal blood flow in the artery used in the recipient bed. It also has been reported that vascular occlusions are less frequent with this type of coupling. Another important indication for end-to-side anastomoses is a significant discrepancy in vessel size. One of the more demanding tasks in making an end-to-side anastomosis is the performance of a perfect arteriotomy. With the aim of facilitating the arteriotomy in end-to-side anastomoses, a new microsurgical instrument has been developed.

Anastomosis, Surgical↗

PubMed2001

Learning and memory: recent findings.

Recent findings from neuroimaging, event-related potential and lesion investigations reflect a rapidly emerging view that the memory system is widely distributed throughout the cortex. It is clear that the pattern of cortical involvement during encoding and retrieval of memories is critically dependent on the nature and complexity of task demands. This has implications, both for existing models of memory function, and in the methodology of future investigations and the issues they address. No consensus has yet been reached on a number of issues, perhaps most notably the role of the hippocampus in retrieval, but advances in measurement techniques should enable some of these matters to be resolved. Further work must address the complex dynamics of the memory system, the extent to which the same regions underlie different functions, and how different regions interact and reflect common functions.

Animals↗

PubMed1980

Isometric strength testing as a means of controlling medical incidents on strenuous jobs.

This investigation was performed to determine if isometric strength tests can be used to select workers for strenuous jobs and to reduce occupational injuries which are caused by a mismatch between worker strength and job strength requirements. Twenty jobs in a tire and rubber plant were studied biomechanically to identify critical strength-demanding tasks. Four strength tests were designed to simulate these tasks, and performance criteria were established for passing the tests. New applicants were administered the tests during their preplacement examinations to determine if they possessed sufficient strength to qualify for the jobs. The medical incidence rate of employees who were selected using the strength tests was approximately one-third that of employees selected using traditional medical criteria. It was concluded that isometric strength tests can be used to reduce occupational injuries and should be considered for implementation in industries with strenuous jobs.

Accidents, Occupational↗

PubMed2003

Early identification and risk management of children with developmental coordination disorder.

PURPOSE: The purpose of this study was to determine the motor control issues, motor learning differences, and secondary impairments of children with developmental coordination disorder (DCD) and to explore physical therapists' contribution to their early management. SUMMARY OF KEY POINTS: DCD is a condition involving limitations in gross motor, postural, and/or fine motor performance that is not attributable to other neurological disorders. Manifestation is varied across children and depends, in part, on their level of anticipatory motor control, response to specific task demands, and ability to attend to feedback to obtain flexible, adaptive movement solutions. Children with DCD rely primarily on vision for feedback, frequently use "fixing" strategies, and exhibit limited motor repertoires. As a result of their movement problems, they tend to avoid physical activity and are prone to secondary impairments, including decreased strength and power. CLINICAL IMPLICATIONS AND RECOMMENDATIONS: Physical therapists can 1) use their keen observational skills to identify children with DCD earlier in life and 2) use their knowledge of the secondary impairments and movement difficulties to work with families to engage children in continuous movement activities to maintain strength and power and thus obtain the physical, social, and psychosocial benefits of physical activity.

Journal Article↗

PubMed1990

Circadian performance rhythms: some practical and theoretical implications.

Safety and productivity are low at night and this would appear to be because we are a diurnal species. This is reflected not only in our habitual sleep time, but also in our endogenous body clocks that, together with exogenous influences, such as the patterning of meals and activity, result in predictable circadian (24 h) rhythms in our physiological processes. Our performance capabilities also vary over the course of our waking period, with task demands affecting both the precise trend over the day, and the rate at which it adjusts to the changes in sleep timing occasioned by shift work. Studies designed to examine the reasons for this have shown that memory loaded performance may have a quite separate endogenous component to that responsible for more simple performance, suggesting that these two types of performance cannot be causally related. Furthermore, it would appear that the exogenous component of circadian rhythms may also differ across measures, and our attempts to model these endogenous and exogenous components have led us to re-examine the evidence on adjustment to night work. Our findings suggest that shiftworkers merely 'stay up late' on the night shift, rather than adjust to it, and that this is responsible for the reduced safety at night. It would seem that in situations where safety is paramount, the only solution to these problems is the creation of a nocturnal sub-society that not only always works at night but also remains on a nocturnal routine on rest days.

Circadian Rhythm↗

PubMed1992

Modelling face recognition.

Much early work in the psychology of face processing was hampered by a failure to think carefully about task demands. Recently our understanding of the processes involved in the recognition of familiar faces has been both encapsulated in, and guided by, functional models of the processes involved in processing and recognizing faces. The specification and predictive power of such theory has been increased with the development of an implemented model, based upon an 'interactive activation and competition' architecture. However, a major deficiency in most accounts of face processing is their failure to spell out the perceptual primitives that form the basis of our representations for faces. Possible representational schemes are discussed, and the potential role of three-dimensional representations of the face is emphasized.

Cognition↗

PubMed1999

How microbial ancient DNA, found in association with human remains, can be interpreted.

The analysis of the DNA of ancient micro-organisms in archaeological and palaeontological human remains can contribute to the understanding of issues as different as the spreading of a new disease, a mummification process or the effect of diets on historical human populations. The quest for this type of DNA, however, can represent a particularly demanding task. This is mainly due to the abundance and diffusion of bacteria, fungi, yeasts, algae and protozoans in the most diverse environments of the present-day biosphere and the resulting difficulty in distinguishing between ancient and modern DNA. Nevertheless, at least under some special circumstances, by using rigorous protocols, which include an archaeometric survey of the specimens and evaluation of the palaeoecological consistency of the results of DNA sequence analysis, glimpses of the composition of the original microbial flora (e.g. colonic flora) can be caught in ancient human remains. Potentials and pitfalls of this research field are illustrated by the results of research works performed on prehistoric, pre-Columbian and Renaissance human mummies.

Animals↗

PubMed2002

Targeting tryptophan decarboxylase to selected subcellular compartments of tobacco plants affects enzyme stability and in vivo function and leads to a lesion-mimic phenotype.

Tryptophan decarboxylase (TDC) is a cytosolic enzyme that catalyzes an early step of the terpenoid indole alkaloid biosynthetic pathway by decarboxylation of L-tryptophan to produce the protoalkaloid tryptamine. In the present study, recombinant TDC was targeted to the chloroplast, cytosol, and endoplasmic reticulum (ER) of tobacco (Nicotiana tabacum) plants to evaluate the effects of subcellular compartmentation on the accumulation of functional enzyme and its corresponding enzymatic product. TDC accumulation and in vivo function was significantly affected by the subcellular localization. Immunoblot analysis demonstrated that chloroplast-targeted TDC had improved accumulation and/or stability when compared with the cytosolic enzyme. Because ER-targeted TDC was not detectable by immunoblot analysis and tryptamine levels found in transient expression studies and in transgenic plants were low, it was concluded that the recombinant TDC was most likely unstable if ER retained. Targeting TDC to the chloroplast stroma resulted in the highest accumulation level of tryptamine so far reported in the literature for studies on heterologous TDC expression in tobacco. However, plants accumulating high levels of functional TDC in the chloroplast developed a lesion-mimic phenotype that was probably triggered by the relatively high accumulation of tryptamine in this compartment. We demonstrate that subcellular targeting may provide a useful strategy for enhancing accumulation and/or stability of enzymes involved in secondary metabolism and to divert metabolic flux toward desired end products. However, metabolic engineering of plants is a very demanding task because unexpected, and possibly unwanted, effects may be observed on plant metabolism and/or phenotype.

Aromatic-L-Amino-Acid Decarboxylases↗

PubMed2006

Optimal reduction of MCG in fetal MEG recordings.

Recording fetal magnetoencephalographic (fMEG) signals in-utero is a demanding task due to biological interference, especially maternal and fetal magnetocardiographic (MCG) signals. A method based on orthogonal projection of MCG signal space vectors (OP) was evaluated and compared with independent component analysis (ICA). The evaluation was based on MCG amplitude reduction and signal-to-noise ratio of fetal brain signals using exemplary datasets recorded during ongoing studies related to auditory evoked fields. The results indicate that the OP method is the preferable approach for attenuation of MCG and for preserving the fetal brain signals in fMEG recordings.

Algorithms↗

PubMedDate not supplied

Image-based collision detection for deformable cloth models.

Modeling the natural interaction of cloth and garments with objects in a 3D environment is currently one of the most computationally demanding tasks. These highly deformable materials are subject to a very large number of contact points in the proximity of other moving objects. Furthermore, cloth objects often fold, roll, and drape within themselves, generating a large number of self-collision areas. The interactive requirements of 3D games and physically driven virtual environments make the cloth collisions and self-collision computations more challenging. By exploiting mathematically well-defined smoothness conditions over smaller patches of deformable surfaces and resorting to image-based collision detection tests, we developed an efficient collision detection method that achieves interactive rates while tracking self-interactions in highly deformable surfaces consisting of a large number of elements. The method makes use of a novel technique for dynamically generating a hierarchy of cloth bounding boxes in order to perform object-level culling and image-based intersection tests using conventional graphics hardware support. An efficient backward voxel-based AABB hierarchy method is proposed to handle deformable surfaces which are highly compressed.

Journal Article↗

PubMedDate not supplied

Children "tune out" in response to the ambiguous communication style of powerless adults.

Changes in children's attentional engagement were assessed as a function of their exposure to "teachers" who differed in perceived power and the communication style that is associated with perceived power. In Study 1, "teachers" (women assigned to an instructional role) were selected on the basis of their perceived power; low-power women were more likely than high-power women to display communication ambiguity. Children responded to low-power women with low levels of (1) autonomic orienting (consistent with low attention) and (2) high errors on a cognitively demanding task (mental arithmetic). Attentional disengagement was found to be mediated by the ambiguous communication style of low-power adults. In Study 2, the "teacher" was a confederate who systematically varied the facial and vocal ambiguity of her instructions. Children showed the lowest levels of orienting and the highest level of errors when the "teacher" was ambiguous in both face and voice. Results were interpreted as showing that adult ambiguity (naturally occurring or experimentally produced) leads to reductions in children's attentional engagement.

Adult↗

PubMedDate not supplied

A nonverbal false belief task: the performance of children and great apes.

A nonverbal task of false belief understanding was given to 4- and 5-year-old children (N = 28) and to two species of great ape: chimpanzees and orangutans (N = 7). The task was embedded in a series of finding games in which an adult (the hider) hid a reward in one of two identical containers, and another adult (the communicator) observed the hiding process and attempted to help the participant by placing a marker on the container that she believed to hold the reward. An initial series of control trials ensured that participants were able to use the marker to locate the reward, follow the reward in both visible and invisible displacements, and ignore the marker when they knew it to be incorrect. In the crucial false belief trials, the communicator watched the hiding process and then left the area, at which time the hider switched the locations of the containers. When the communicator returned, she marked the container at the location where she had seen the reward hidden, which was incorrect. The hider then gave the subject the opportunity to find the sticker. Successful performance required participants to reason as follows: the communicator placed the marker where she saw the reward hidden; the container that was at that location is now at the other location; so the reward is at the other location. Children were also given a verbal false belief task in the context of this same hiding game. The two main results of the study were: (1) children's performance on the verbal and nonverbal false belief tasks were highly correlated (and both fit very closely with age norms from previous studies), and (2) no ape succeeded in the nonverbal false belief task even though they succeeded in all of the control trials indicating mastery of the general task demands.

Analysis of Variance↗

PubMed1998

Phonological representation and speech understanding with cochlear implants in deafened adults.

In the present study cognitive performance in 15 deafened adult cochlear implant candidates was examined and related to level of speech understanding after 12 months of experience with the implant. The implant group performed on par with normal hearing controls in all cognitive tasks used in the study with one exception: Performance was significantly lower in cognitive tasks where use of a phonological representation of sound is a key task-demand. Observations of the implanted individuals' level of speech understanding indicate that only those individuals who, pre-operatively, were in possession of phonological representations comparable to that of normal hearing could follow and understand a speaker that was out of sight. The results are discussed with respect to (a) deterioration in the phonological representation of sounds as a function of absence of external auditory stimulation, and (b) the role of cognitive factors in predicting success in speech understanding with the implant.

Adult↗