RESUMEN
A total of 83 drivers, 51 males and 32 females, aged 25-65, were recruited to drive an apparently unmodified passenger car for 1 h over at least four laps of a predetermined route on public roads, which included seven sets of traffic lights and sections limited to 50, 70, 90 and 110 km/h. They were randomly assigned to one of two thermal conditions (21 or 27 degrees C), and drove only during the hours of daylight. A computer initiated unprepared signals to which drivers would normally be alert. Drivers responded by pressing a foot-switch and reporting verbally. Signals were selected at random from 21 possible signals, and were presented for up to 3 min, with a random delay of 30-180 s after each response or failure to respond. The negative effect of heat stress on vigilance was statistically significant. At 27 degrees C, the overall proportion of missed signals was 50% higher and response times were 22% longer than they were at 21 degrees C. These effects of heat were significant and proportionally greater in the second half-hour, for subjects < 40 years and for speeds below 60 km/h (i.e. in city traffic). The latter finding suggests that heat may have increased arousal, and there was some indication of a redistribution of attention away from the most peripheral signals at the higher temperature. Overt driving errors were observed significantly more often at 27 degrees C than at 21 degrees C for women only.
Asunto(s)
Atención , Conducción de Automóvil/psicología , Agotamiento por Calor/psicología , Adulto , Anciano , Nivel de Alerta , Femenino , Calor/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Orientación , Valores de ReferenciaRESUMEN
The objective of this study was to investigate if the dust in a mill producing soft paper tissue caused respiratory symptoms or impaired respiratory function. Using a questionnaire and spirometry, 355 persons were examined. They were divided into three groups according to present exposure to dust; low (less than 1 mg/m3), moderate (1-5 mg/m3) and heavy (greater than 5 mg/m3). There was a dose-dependent increase of symptoms from the upper respiratory tract. However, coughing and coughing with phlegm were not found to be more common among persons with heavy exposure compared to those with low exposure to the dust. There was no difference in FEV1 or FVC during a work shift. Persons with long-term (greater than 10 years) and heavy exposure to dust seemed to have impaired respiratory function compared to those with low and/or short-term exposure to the dust.
Asunto(s)
Polvo/efectos adversos , Enfermedades Profesionales/etiología , Papel , Enfermedades Respiratorias/etiología , Adulto , Bronquitis/etiología , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Capacidad VitalRESUMEN
Radiative cooling power was computed as a function of the emittance c, of an exposed surface, air temperature, humidity, etc. from the LOWTRAN 5 code. Meteorological data were then used to make semiquantitative estimates on how often frost will form on a surface with given epsilon(s). Practical tests, using SnO(2)-covered glass with epsilon(s) approximately 0.2, demonstrated that a low-emittance coating can prevent frost formation and maintain transparency of a window exposed to the clear sky.