RESUMEN
INTRODUCTION: With growing freight operations throughout the world, there is a push for transportation systems to accommodate trucks during loading and unloading operations. Currently, many urban locations do not provide loading and unloading zones, which results in trucks parking in places that obstruct bicyclist's roadway infrastructure (e.g., bicycle lanes). METHOD: To understand the implications of these truck operations, a bicycle simulation experiment was designed to evaluate the impact of commercial vehicle loading and unloading activities on safe and efficient bicycle operations in a shared urban roadway environment. A fully counterbalanced, partially randomized, factorial design was chosen to explore three independent variables: commercial vehicle loading zone (CVLZ) sizes with three levels (i.e., no CVLZ, Min CVLZ, and Max CVLZ), courier position with three levels (i.e., no courier, behind the truck, beside the truck), and with and without loading accessories. Bicyclist's physiological response and eye tracking were used as performance measures. Data were obtained from 48 participants, resulting in 864 observations in 18 experimental scenarios using linear mixed-effects models (LMM). RESULTS: Results from the LMMs suggest that loading zone size and courier position had the greatest effect on bicyclist's physiological responses. Bicyclists had approximately two peaks-per-minute higher when riding in the condition that included no CVLZ and courier on the side compared to the base conditions (i.e., Max CVLZ and no courier). Additionally, when the courier was beside the truck, bicyclist's eye fixation durations (sec) were one (s) greater than when the courier was located behind the truck, indicating that bicyclists were more alert as they passed by the courier. The presence of accessories had the lowest influence on both bicyclists' physiological response and eye tracking measures. PRACTICAL APPLICATIONS: These findings could support better roadway and CVLZ design guidelines, which will allow our urban street system to operate more efficiently, safely, and reliable for all users.
Asunto(s)
Accidentes de Tránsito , Ciclismo , Humanos , Accidentes de Tránsito/prevención & control , Simulación por Computador , Modelos Lineales , Vehículos a Motor , Distribución AleatoriaRESUMEN
The leukotriene receptor antagonists (LTRAs) is a relatively new class of asthma medication with a lack of toxicity for unintentional poisoningsituations. This makes it difficult to determine which exposures require aggressive decontamination or simple monitoring in the home setting: prompting the question, "What LTRA dose is likely to produce significant toxicity?" We report a case of an unintentional poisoning with 80 mg montelukast in a 3-y-o asthmatic child that was managed in the home with observation alone and a second case of untentional 135 mg montelukast poisoning in a 5-y-o asthmatic child managed in an emergency department. In both cases, symptoms were not observed. These cases and available literature suggest that doses < 4.5 mg/kg in children result in minimal toxicity.