Road traffic noise around schools: a risk for pupil's performance?

Summary Noise levels around educational centres can negatively affect the performance of both teachers and pupils. Two public schools in Valencia, Spain, were selected for study. One of these schools was exposed to excessively high road traffic noise levels while the other was located in a relatively quiet area. The socioeconomic level of those attending the schools was very similar. A set of external and internal noise measurements were carried out, along with two different attention tests among the children. Test results were consistently better (both for tests and for children from different classrooms in each school) in the quiet school. Exposure to high traffic noise levels in the noisy school over the whole school year is a plausible determinant of these results.     

Facilitation of stimulus detection performance of rats with d-amphetamine: a function of dose and level of training

 Conditions under which amphetamine may facilitate stimulus detection task choice performance in rats were investigated. Rats (n=15) were trained in a two-choice, light-detection task to three successively more stringent criterion levels of task training (minimal, intermediate, and extended) and then tested after administration of saline, 0.25, 0.50, and 0.75 mg/kg d-amphetamine (AMP). For each training level, baseline levels of choice accuracy were maintained at approximately 82% by manipulating the animals’ cue duration. No aspect of performance was enhanced by any dose of AMP after minimal criteria training, and there was a dose-dependent decrease in the number of trials completed. After the intermediate level of training, the 0.25 mg/kg dose of AMP reliably increased choice accuracy, there was no reliable change in choice reaction time, and there was a dose-dependent decrease in the number of trials completed. After the extended training, the 0.25 mg/kg dose of AMP reliably increased choice response accuracy, the 0.25 and 0.50 mg/kg doses of AMP reliably decreased choice reaction time, and there was no reliable change in the number of trials completed at any dose of AMP. These results support the contention that psychostimulants can facilitate the choice performance of rats in stimulus detection tasks if an appropriately low dose is used and the animal’s behavior is strongly controlled by the stimulus-reinforcement contingencies of the task. Received: 24 September 1997 / Final version: 9 May 1998     

ROBUST GUARANTEED COST CONTROL OF UNCERTAIN NON-LINEAR ROBOTIC SYSTEM USING MIXED MINIMUM TIME AND QUADRATIC PERFORMANCE INDEX

To provide better transient performance in controlling robots, a mixed minimum time and quadratic performance index is used. For known and uncertain revolute robot manipulators a conventional optimal control and a robust guaranteed cost control are proposed respectively. Asymptotic stability is also discussed based on the Lyapunov direct method. The proposed robust control is continuous and requires no knowledge of the uncertain system except for bounding functions.     

Muscular performance after a 3 month progressive physical exercise program and 9 month follow-up in subjects with low back pain. A controlled study

The purpose of this study was to assess, in subjects with low back pain, the changes and their permanence in muscular performance after a 3 month progressive physical exercise program. Ninety subjects with chronic low back pain participated in the study. The study design was controlled and it was carried out in three groups: intensive training, home exercise, and control group. Isometric and dynamic muscle strength of the trunk and lower limb were measured, at the beginning of the study and after the 3 months exercise program, and then during each of the follow-up sessions. The Oswestry Index and back pain intensity were also determined. Both exercise groups received benefit from the progressive exercise program. Their muscular performance improved and their back pain intensity decreased significantly. Among the home exercise group, the Oswestry Index also changed positively. The results demonstrate that the home exercise program could be as effective as the intensive training program in increasing muscle strength, as well as decreasing back pain and functional disability among low back pain patients with mild functional limitations.     

Visual and psychomotor performance of elite,intermediate and novice table tennis competitors

The purpose of this cross-sectional study was to determine whether measures on a selected groups of visual and psychomotor variables distinguished between groups of elite, intermediate and novice table tennis players. The variables included commonly of Melbourne measured clinical functions such as static visual acuity, extent of visual field and oculomotor balance and more experimental visual tasks such as recognition of, peripheral targets, saccadic latency and dynamic visual acuity. Psychomotor performance was assessed by measures of simple reaction time, choice response time and hand movement time. Although elite level competitors had significantly better dynamic visual acuity, a wider visual field and superior recognition of peripheral targets compared to less skilled competitors, the magnitude, or practical significance of these differences was not great and individually accounted for less than 5 per cent of population variance. Elite competitors had significantly faster psychomotor responses than novice players with die skill variables individually accounting for between 21 per cent and 62 per cent of population variance in psychomotor performance. These results indicate that the psychomotor parameters could be a useful part of a test battery for talent identification amongst table tennis players.     

Effect of forward rapidly rotating shift work on circadian rhythms of arterial pressure, heart rate and oral temperature in air traffic controllers

Twenty-four-hour records of arterial pressure (AP), heart rate(HR), oral temperature (OT) and physical and mental performancewere obtained in air traffic controllers during morning (n=16),afternoon (n=17) and night (n=19) shifts. Data were analyzedby the cosinor method. The results obtained during the morningshift were as follows (mesor/amplitude/;acrophase): systolicAP (mm Hg)—113.6/10.0/16:03 h; diastolic AP—71.1/8.2—15:19h; mean AP—85.6/8.8/15:41 h; HR (beats/min)—77.5/8.9/16:00h; OT (dg C)—36.71/0.21/15:49 h; right-hand grip strength(kg)—49.8/2.0/17:43 h; left-hand grip strength—46.1/2.0/16.08h; mental performance (calculations/min)—14.9/1.1/16:39h. During the night shift either no change of the circadianacrophases (HR, right-hand grip strength) or acrophase delaysranging from about 2 h (systolic AP, OT, mental performance)up to 3 h (diastolic and mean AP, left-hand grip strength) wereobserved. Our data suggest that the shift system studied doesnot significantly alter the circadian rhythms, and does notinduce a desynchronization, particularly as concerns arterialpressure and oral temperature.     

Work at sea: a study of sleep,and of circadian rhythms in physiological and psychological functions,in watchkeepers on merchant vessels

Summary Daily diary records of sleep and activity, and 4-h measurements of body temperature, performance and subjective alertness were collected on board ship from 15 watchkeepers on the 4-on/8-off system, and from 28 dayworkers, on both westward and eastward transatlantic voyages. The data from a balanced sample of the subjects were analysed over selected 8-d periods of the voyages where four or five time zones were crossed. During these periods the average amount of daily sleep obtained by dayworkers on the eastward voyage was more than 1 h less than that on the westward voyage, and its quality was rated lower. Watchkeepers' main sleep was also shorter when travelling eastward, but this reduction was partially compensated for by a slightly longer secondary sleep. With the exception of subjective alertness on the eastward voyage, the basic phase of the circadian rhythms in the measured variables adjusted appropriately to the clock changes associated with the time zone crossings. The normal shape of the average daily curves was, however, altered differentially in the two directions of travel; as a result, morning levels of all variables were lower on the eastward voyage than on the westward, but evening levels were higher. These distortions of rhythm waveforms, which probably arose from a combination of endogenous and exogenous factors, add another dimension to the basic problem caused by the effects of circadian rhythms on operational efficiency in the shipboard situation. This problem can only be solved by the development of alternative watchkeeping systems which take full account of these rhythms.Partly supported by a grant from the West German Ministry for Technology and Research, Project Schiff der Zukunft, Part ET 83b     

高效液相色谱分析虚拟仿真教学实施及效果评价

目的 研究传统教学结合虚拟仿真教学在高效液相色谱法中进行药物含量分析的教学效果。方法 以2016级两个平行班的学生为研究对象,分为试验组（44名）和对照组（38名）。以高效液相色谱法分析甲硝唑注射液含量及其方法学研究为例,试验组采用传统线下教学结合虚拟仿真教学,对照组采用传统线下教学。通过比较两组期中、期末考试成绩来评价两组教学效果。用SPSS 22.0软件进行独立样本t检验。结果 期中测试结果表明试验组在实际操作考核方面优于对照组[（17.98±6.75） vs. （14.03±5.92）],差异有统计学意义（P < 0.05）,而在理论、汇报及报告成绩方面两组差异无统计学意义。两组期末考试成绩各方面差异都无统计学意义。结论 采用传统线下教学结合虚拟仿真训练,可提高学生的实际操作能力,有助于提高药物含量分析实验的教学效果。通过本项目的训练,学生掌握了高效液相色谱法操作、药物制剂的含量测定、分析方法的验证、数据处理及分析报告的撰写等能力,具备了一定的实际分析工作能力。     

Divided attention performance in cannabis users and non-users following alcohol and cannabis separately and in combination

The effect of 9-tetrahydrocannabinol ( 9-THC) and alcohol, singly and in combination, on divided attention performance was investigated in cannabis users and non-users who were matched for alcohol use. Both cannabis and alcohol produced decrements in central and peripheral signal detections. Drug and alcohol effects were greater for signal presentations in the periphery. Cannabis users were less impaired in peripheral signal detection than non-users while intoxicated by cannabis and/or alcohol. These findings suggest the development of tolerance and cross-tolerance in regular cannabis users and/or the ability to compensate for intoxication effects.