Factors associated with NO2 and NOX concentration gradients near a highway.

The objective of this research is to learn how the near-road gradient, in which NO2 and NOX (NO + NO2) concentrations are elevated, varies with changes in meteorological and traffic variables. Measurements of NO2 and NOX were obtained east of I-15 in Las Vegas and fit to functions whose slopes (dCNO2 /dx and dCNOX /dx, respectively) characterize the size of the near-road zone where NO2 and NOX concentrations from mobile sources on the highway are elevated. These metrics were used to learn about the near-road gradient by modeling dCNO2 /dx and dCNOX /dx as functions of meteorological variables (e.g., wind direction, wind speed), traffic (vehicle count), NOX concentration upwind of the road, and O3 concentration at two fixed-site ambient monitors. Generalized additive models (GAM) were used to model dCNO2 /dx and dCNOX /dx versus the independent variables because they allowed for nonlinearity of the variables being compared. When data from all wind directions were included in the analysis, variability in O3 concentration comprised the largest proportion of variability in dCNO2 /dx, followed by variability in wind direction. In a second analysis constrained to winds from the west, variability in O3 concentration remained the largest contributor to variability in dCNO2 /dx, but the relative contribution of variability in wind speed to variability in dCNO2 /dx increased relative to its contribution for the all-wind analysis. When data from all wind directions were analyzed, variability in wind direction was by far the largest contributor to variability in dCNOX /dx, with smaller contributions from hour of day and upwind NOX concentration. When only winds from the west were analyzed, variability in upwind NOX concentration, wind speed, hour of day, and traffic count all were associated with variability in dCNOX /dx. Increases in O3 concentration were associated with increased magnitude near-road dCNO2 /dx, possibly shrinking the zone of elevated concentrations occurring near roads. Wind direction parallel to the highway was also related to an increased magnitude of both dCNO2 /dx and dCNOX /dx, again likely shrinking the zone of elevated concentrations occurring near roads. Wind direction perpendicular to the road decreased the magnitude of dCNO2 /dx and dCNOX /dx and likely contributed to growth of the zone of elevated concentrations occurring near roads. Thus, variability in near-road concentrations is influenced by local meteorology and ambient O3 concentration.

Effect of low light and high noise on behavioural activity, physiological indicators of stress and production in laying hens.

1. Commercial laying hens are commonly housed in noisy and dim environments, yet relatively little is known about whether these conditions, particularly in combination, have any effect on welfare or egg production. 2. The study was designed to investigate whether chronic exposure to continuous noise (60 dB(A) vs. 80 dB(A)) and/or light intensity (150 lux vs. 5 lux) during the critical period of coming into lay (16-24 weeks of age) influenced behaviour (activity, resting and feather maintenance), physiological stress (plasma corticosterone and heterophil to lymphocyte ratio) and production (number and weight of eggs laid) in laying hens. 3. Hens in the low light pens were less active and preened and dust-bathed more than those housed in 150 lux; hens in the high noise pens rested more frequently than those in quieter pens. 4. There was no evidence that chronic exposure to low light or high noise caused appreciable physiological stress but egg production was affected by these conditions. Hens kept in pens with low light or high noise laid fewer eggs per day than those kept in high light or low noise pens. These effects were additive, so that the fewest eggs were laid by hens subject to both low light and high noise. 5. These results show that low light intensity and continual high background noise have a detrimental effect on egg production in the early laying phase as well as influencing the time allocated to different behaviours. However there was no strong evidence for a physiological stress response to either of these conditions or their combination.

Is there still a place for emergency department thrombolysis following the introduction of the amended Joint Royal Colleges Ambulance Liaison Committee criteria for thrombolysis?

OBJECTIVE: To apply the current (2004) and the amended (2006) Joint Royal Colleges Ambulance Liaison Committee (JRCALC) criteria for paramedic initiated thrombolysis to all patients who received thrombolytic treatment in an emergency department (ED) to determine if the amendments increase the proportion suitable for paramedic initiated thrombolysis. DESIGN: Retrospective descriptive analysis. METHOD: The ED clinical notes, ambulance clinical record and the first recorded ECG (ED or ambulance) of all patients thrombolysed in the ED during a 12 month period were reviewed against the previous JRCALC guidelines (2004) and the amended JRCALC guidelines (2006) for thrombolysis. RESULTS: Using the JRCALC guidelines (2004), 26 of the 147 patients (17.7%) were eligible for paramedic initiated thrombolysis. Using the JRCALC guidelines (2006), this increased to 41 (27.9%). This difference was statistically significant (McNemar's I2 test with 1 degree of freedom = 15.00; p<0.001). The change to the blood pressure, age and pulse rate parameters has increased the percentage eligible for paramedic initiated thrombolysis by 10.2% (95% confidence interval 4.6% to 15.8%). CONCLUSION: The amended JRCALC guidelines (2006) for paramedic initiated thrombolysis have successfully increased the proportion of patients suitable for prehospital thrombolysis by approximately 10%, although the ED retains an important role in the provision of prompt thrombolytic treatment for a proportion of patients.

The impact of chronic environmental stressors on growing pigs, Sus scrofa (Part 1): stress physiology, production and play behaviour.

Commercially farmed animals are frequently housed in conditions that impose a number of concurrent environmental stressors. For pigs housed indoors, elevated levels of mechanical noise, atmospheric ammonia and low light intensities are commonplace. This experiment examined the effects on growing pigs of chronic exposure to combinations of commercially relevant levels of these potential stressors. Four-week-old hybrid female pigs (n = 224) were housed under experimentally manipulated conditions of nominally either <5 or 20 ppm atmospheric concentration of ammonia (24 h), a light intensity of 40 lux or 200 lux (12 h) and mechanical noise at either ⩽60 or 80 dB(A) (24 h) for 15 weeks in a fully factorial arrangement (23) of treatments. The response of pigs to these environmental factors was assessed using a suite of physiological, production and behavioural measures. These included indicators of hypothalamic-pituitary-adrenal (HPA) axis activation such as salivary cortisol and adrenal morphometry, as well as body weight, food conversion efficiency and general health scores. Play behaviour was recorded as it is thought to be inversely related to stress. Chronic exposure to ammonia produced the strongest effect, shown by lower concentrations of salivary cortisol and larger adrenal cortices in the pigs reared under 20 ppm ammonia, which may have been indicative of a period of HPA activation leading to a downregulation of cortisol production. The pigs in the ammoniated rooms also performed less play behaviour than pigs in non-ammoniated rooms. There was evidence for an interaction between high noise and ammonia on the health scores of pigs and for brighter light to ameliorate the effect of ammonia on salivary cortisol. However, there was no measurable impact of these potential stressors on the productivity of the pigs or any of the other physiological parameters measured. We conclude that there should be little concern in terms of performance about the physical stressors tested here, within current European Union legal limits. However, 20 ppm ammonia may have had an adverse influence on the well-being of growing pigs. In this study, all other aspects of the pigs' husbandry were optimal; therefore, it is possible that under less favourable conditions, more pronounced effects of ammonia, noise and dim light would be observed.

The impact of chronic environmental stressors on growing pigs, Sus scrofa (Part 2): social behaviour.

The effects of common and concurrent environmental stressors on the social behaviour of farm animals are poorly understood. Here, we report the results of a multifactorial experiment designed specifically to examine the individual, additive or interactive effects of elevated ammonia, noise and low light (LL) levels on the social behaviour of growing pigs. Social behaviour was measured in terms of the nature, frequency and duration of both initiated and response behaviours for 4 weeks following mixing of the groups. General activity patterns, group cohesion and social discrimination were also examined as a function of the environmental treatments. Elevated concentrations of atmospheric ammonia (∼20 v. <5 ppm) and LL intensity (∼40 v. 200 lux) had the most pronounced effects, particularly on the nature of social interactions, with pigs under these conditions showing more aggression in the early stages of the experiment. In addition, pigs exposed to a high level of mechanical noise representative of artificial ventilation (∼80 v. 40 dB [A]) were less submissive to aggressive acts, while pigs in ∼20 ppm ammonia showed more reciprocated aggression when in coincident LL (<40 lux). The results indicate that atmospheric ammonia at commonly experienced concentrations may undermine social stability, particularly in the presence of low lighting, though the mechanisms are currently unknown. These findings have implications for the welfare of growing pigs and hence policy makers and farmers alike, with respect to the improvement of welfare in intensive pig farming.