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Stimulus-driven attentional capture is contingent on attentional set for displaywide visual features.

This research showed that the current criterion for stimulus-driven attentional capture is not sufficient to rule out goal-directed processes that are critical for producing attentional capture. This was shown by demonstrating a contingency between displaywide visual features (i.e., features that signal the appearance of the task-relevant target display as a whole) and the features that capture attention. In Experiment 1, the target display was signaled by both color and onset; in Experiment 2, the target display was signaled only by onset. As expected, Experiment 1 showed that task-irrelevant color and onset distractors both captured attention, whereas Experiment 2 showed that only onset distractors captured attention. These contingencies suggest that the strongest evidence currently available for stimulus-driven attentional capture may be caused by goal-directed processes.

Analysis of Variance↗

Watching a cursor distorts haptically guided reproduction of mouse movement.

Participants moved a mouse along a force-feedback-defined linear path, either without vision or while watching a cursor set to 1 of 3 levels of visual:haptic gain (all >1:1). They attempted to haptically reproduce the movement without visual feedback. Errors increased with gain, reaching 70% overestimation at the highest gain. Forewarning participants about gain variability did not eliminate this effect. The gain level was potentially cued during the movement by the mismatch between visual feedback and kinesthetic feedback. Moreover, because participants did not achieve cursor-speed constancy across gain levels, visual speed was another cue to gain. Collectively, these cues failed to prevent visual distortion of movement reproduction.

Attention↗

The prokaryotic selenoproteome.

In the genetic code, the UGA codon has a dual function as it encodes selenocysteine (Sec) and serves as a stop signal. However, only the translation terminator function is used in gene annotation programs, resulting in misannotation of selenoprotein genes. Here, we applied two independent bioinformatics approaches to characterize a selenoprotein set in prokaryotic genomes. One method searched for selenoprotein genes by identifying RNA stem-loop structures, selenocysteine insertion sequence elements; the second approach identified Sec/Cys pairs in homologous sequences. These analyses identified all or almost all selenoproteins in completely sequenced bacterial and archaeal genomes and provided a view on the distribution and composition of prokaryotic selenoproteomes. In addition, lineage-specific and core selenoproteins were detected, which provided insights into the mechanisms of selenoprotein evolution. Characterization of selenoproteomes allows interpretation of other UGA codons in completed genomes of prokaryotes as terminators, addressing the UGA dual-function problem.

Amino Acid Sequence↗

Influence of the digital image display monitor on observer performance.

OBJECTIVE: To assess the influence of the display monitor on observer performance. MATERIAL AND METHODS: Artificial enamel lesions were created in 40 extracted teeth at random using 1/4 and 1/2 round burs. Teeth were mounted in dental stone blocks to simulate a hemidentition. Approximate exposures were recorded at 70 kVp using a Digota (Soredex, Orion Corp, Helsinki, Finland) digital imaging system, calibrated to achieve optimum density. Six dentists rated each image on a five-point scale for the presence or absence of a lesion. Radiographic images were viewed on the following monitors: (1) AlphaScan 711 (Sampo Corp.); (2) Multiscan 17 Se II (Sony Electronics Inc.); (3) DS 2000 (Clinton Electronics Corp.) and (4) Latitude CP Laptop (Dell Computer Corp.). Raters were allowed to magnify and to adjust density and contrast of each image at will. Receiver Operating Characteristic (ROC) analysis was performed and curves were plotted for each image. Data was subjected to repeated measures analysis of variance and ordinal logistic regression to test for significance between variables and to determine odds ratios. RESULTS: Mean ROC curve areas ranged from 0.8728 for the Sampo monitor to 0.8395 for the Sony. Repeated measures analysis of variance showed significant differences between observers (P < 0.0001), lesion size (P < 0.0001), examiner/monitor interaction (P < 0.033) and examiner/block interaction (P < 0.013). However, no significant difference was found between monitors. CONCLUSION: This study suggests that observer performance is independent of the visual characteristics of the display monitor.

Analysis of Variance↗

Influence of room lighting on grey-scale perception with a CRT-and a TFT monitor display.

OBJECTIVES: To determine the influence of ambient lighting on grey-scale perception using a cathode-ray tube (CRT) and a thin film transistor (TFT) computer display. METHODS: A cathode ray tube (Nokia XS 446) and a liquid crystal display (Panasonic LC 50S) were used at reduced room lighting (70 lux) and under conditions recommended for a dental operatory (1000 lux). Twenty-seven observers examined twice a modified SMPTE test pattern [0 to 255; 255 to 0] grey-scale values. The corresponding contrast differences were allocated to four ranges of grey levels (I: 0-63; II: 64-127; III: 128-191; IV: 192-255). The influences of monitor type, grey-scale range and illumination were evaluated by means of repeated measures analysis of variance. RESULTS: Detection of differences in monochromatic intensity was significantly earlier with reduced lighting (P<0.0001). When full ambient lighting was used, the TFT display was superior compared to the CRT monitor in ranges II and III (P<0.0001), whereas no differences could be detected for grey intensities between 0 and 63 (P=0.71) and between 192 and 255 (P=0.36). CONCLUSIONS: Background lighting hampers grey-scale perception on computer displays. In this study of one TFT and one CRT monitor, the TFT in full ambient lighting was associated with earlier detection of grey scale differences than CRT.

Adult↗

Measurement strategy and instrumental performance of a computer screen photo-assisted technique for the evaluation of a multi-parameter colorimetric test strip.

A measuring strategy for the evaluation of a seven parameters colorimetric test using a computer screen photo-assisted technique (CSPT) is demonstrated. CSPT is a versatile approach aimed at point of care or home tests that uses regular computer sets and web cameras as the whole instrument. Issues such as the stability and the equivalency on different platforms of the determinations have been addressed in the present work. The method uses an embedded local reference simultaneously measured with the tests and solves the evaluation as a classification problem. The achieved performance tested along 580 classifications covering all the ranges of the assay, using synthetic samples, yielded 97.2% correct determinations compared with 89.7% for the case of colorimetric determinations. The errors were concentrated in only two parameters that show a significant correlation with a set of quality indices used to assess the performance of the classification.

Colorimetry↗

Effect of fingerprint conformation and spectral scaling on the performance of computer screen photo-assisted experiments.

The use of computer screens as controlled light sources and web cameras as image detectors (the so-called computer screen photo-assisted technique, CSPT) is an ubiquitous alternative for the evaluation of colorimetric quick tests at homes or in primary care units. The performance of CSPT for such evaluations depends on several factors, from which the most relevant are the composition of illuminating sequences and the conformation of CSPT substance signatures. In this work, with the aid of a CSPT model, the effect of the construction of the substance signatures on the classification performance of different representative substance sets is studied. The correlation of illuminating colors with such classification is investigated, allowing one to determine redundancy and limitations with respect to visible spectroscopy. The concept of spectral scaling is introduced and its properties compared with standard procedures.

Colorimetry↗

Comparison of a new video-optical intubation stylet versus the conventional malleable stylet in simulated difficult tracheal intubation.

Handling and efficacy of a new video-optical intubation stylet were assessed in a simulated difficult tracheal intubation setting and compared with a conventional malleable stylet. Forty-five anaesthetists performed 10 tracheal intubations using both techniques. Laryngoscopy was performed by the observer, who created a grade 3 view according the classification by Cormack and Lehane. The time taken to place the tracheal tube and the final tracheal tube positions were documented. Mean (SD) intubation time for the video-optical stylet was 20.4 (7.7) s and for the malleable stylet 10.2 (3.3) s (p<0.01). With the video-optical stylet the trachea was correctly intubated in all 225 attempts; with the malleable stylet 44 (19.6%) oesophageal and 44 (19.6%) endobronchial intubations occurred (p<0.01). The video-optical intubation stylet enabled us to recognise inappropriate tracheal tube positions and to correct them immediately. This equipment can be considered a reliable and effective tool for management of the difficult airway.

Computer Terminals↗

Can we use video images to triage pigmented lesions?

BACKGROUND: Advances in telemedicine permit consultations where the doctor and patient are at different sites. OBJECTIVES: To determine whether this technology could be used to triage referrals of pigmented lesions to a dermatology out-patient clinic, and thereby assist in managing the ever increasing number of lesions being referred. METHODS: When patients attended clinic, a clinical diagnosis of their pigmented lesion was made and recorded. A still image of each lesion was subsequently taken from a video camera using a PC card, and stored. These images were subsequently viewed in conjunction with the general practitioner's referral information and designated as 'warrants referral' or 'does not warrant referral'. For each lesion this decision was compared with the clinical diagnosis made during the live consultation in the clinic (the 'gold standard'). Clinical diagnoses designated as warranting referral were malignant melanoma, basal cell carcinoma, keratoacanthoma, atypical naevus and pyogenic granuloma (due to the potential clinical confusion with amelanotic melanoma). Lesions that were not considered to warrant referral included benign melanocytic naevus, seborrhoeic keratosis, dermatofibroma, congenital naevus, solar lentigo, actinic keratosis and various other benign conditions. RESULTS: In total, 819 lesions were evaluated, resulting in a mean sensitivity of 81% and specificity of 73% for the technique. CONCLUSIONS: We feel that the overall sensitivity of 81% is encouraging as regards the use of such a technique as a triage tool, but that the inability to examine the whole patient or palpate the lesions is a major drawback in the safe triage of patients with pigmented lesions.

Adolescent↗

Uncovering the causes of poor quality pathology laboratory services in acute myocardial infarction.

A study was undertaken to identify the causes that contributed to poor quality pathology services for hospitalized patients with acute myocardial infarction. Through the use of continuous quality improvement (CQI) strategies, the procedure involved a systematic process analysis which assessed the types and sources of variation, and possible causal factors for changes in performance. Thirteen suspected causes of poor quality were identified and data collected to confirm or reject their involvement. The study demonstrated that even strongly suspected causes of poor quality need to be confirmed by data. We found that 23% of the suspected root causes were not substantiated by the data collected. The CQI approach was process driven and should be adaptable to other clinical situations and not just pathology services.

Computer Terminals↗

Exploring the flicker effect: the influence of in-flight pulsations on saccadic control.

The pulsating illumination of visual display units is known to induce systematic changes in saccade extent. In two experiments reported in this paper, we further examined this effect, by looking at the location of pulsations relative to saccade onset. Both saccade extent and velocity were shown to increase as a function of the number of 'in-flight' pulsations. This result indicates that part of the so-called 'flicker effect' originates during the saccade itself. From a more general point of view, the present data suggest that saccadic control can be modulated by intra-saccadic visual stimuli.

Computer Terminals↗

An ergonomic evaluation comparing desktop, notebook, and subnotebook computers.

OBJECTIVE: To evaluate and compare the postures and movements of the cervical and upper thoracic spine, the typing performance, and workstation ergonomic factors when using a desktop, notebook, and subnotebook computers. DESIGN: Repeated-measures design. SETTING: A motion analysis laboratory with an electromagnetic tracking device. PARTICIPANTS: A convenience sample of 21 university students between ages 20 and 24 years with no history of neck or shoulder discomfort. INTERVENTION: Each subject performed a standardized typing task by using each of the 3 computers. MAIN OUTCOME MEASURES: Measurements during the typing task were taken at set intervals. RESULTS: Cervical and thoracic spines adopted a more flexed posture in using the smaller-sized computers. There were significantly greater neck movements in using desktop computers when compared with the notebook and subnotebook computers. The viewing distances adopted by the subjects decreased as the computer size decreased. Typing performance and subjective rating of difficulty in using the keyboards were also significantly different among the 3 types of computers. CONCLUSIONS: Computer users need to consider the posture of the spine and potential risk of developing musculoskeletal discomfort in choosing computers.

Adult↗

[Asthenopic complaints and ocular convergence at the computer workstation: new test procedures for practice and research].

BACKGROUND: The present paper summarizes a series of ergonomic studies on the relation between asthenopic complaints and binocular vision at the computer workstation. In particular, the paper reports on measurements of the accuracy of ocular convergence during fixation of central fusion stimuli (i. e. fixation disparity) as a function of viewing distance. METHODS: Different versions of subjective tests for fixation disparity (using dichoptic nonius lines) are presented, including a computer-controlled procedure (the eye-test PC). RESULTS: These new tests suggest that non-presbyopic subjects with normal binocular vision may suffer from asthenopic complaints if they have - in near vision - an exo fixation disparity larger than average. CONCLUSION: In these cases, the stress exercised on the convergence system can be reduced by using a longer viewing distance at the workplace.

Accommodation, Ocular↗

[Pattern-induced after effects caused by an on-screen workstation].

Millions of people work or spend their free time sitting in front of VDUs that induce contingent visual effects. However, only a few notice irritations in the course of everyday work: motion after-images such as the waterfall illusion or tilt after-effects are possible. A new effect may be caused by those new VDU monitors which have an almost square pattern in the display matrix in which the vertical lines are thicker than the horizontal lines. After-images persisting for days are described when this pattern has an edge length of 0.3 mm and over. These effects are of little concern to most users of VDUs.

Adult↗