Passenger muscle responses in lane change and lane change with braking maneuvers using two belt configurations: Standard and reversible pre-pretensioner

Abstract

Objective: The introduction of integrated safety technologies in new car models calls for an improved understanding of the human occupant response in precrash situations. The aim of this article is to extensively study occupant muscle activation in vehicle maneuvers potentially occurring in precrash situations with different seat belt configurations.

Methods: Front seat male passengers wearing a 3-point seat belt with either standard or pre-pretensioning functionality were exposed to multiple autonomously carried out lane change and lane change with braking maneuvers while traveling at 73?km/h. This article focuses on muscle activation data (surface electromyography [EMG] normalized using maximum voluntary contraction [MVC] data) obtained from 38 muscles in the neck, upper extremities, the torso, and lower extremities. The raw EMG data were filtered, rectified, and smoothed. All muscle activations were presented in corridors of mean?±?one standard deviation. Separate Wilcoxon signed ranks tests were performed on volunteers’ muscle activation onset and amplitude considering 2 paired samples with the belt configuration as an independent factor.

Results: In normal driving conditions prior to any of the evasive maneuvers, activity levels were low (<2% MVC) in all muscles except for the lumbar extensors (3–5.5% MVC). During the lane change maneuver, selective muscles were activated and these activations restricted the sideway motions due to inertial loading. Averaged muscle activity, predominantly in the neck, lumbar extensor, and abdominal muscles, increased up to 24% MVC soon after the vehicle accelerated in lateral direction for all volunteers. Differences in activation time and amplitude between muscles in the right and left sides of the body were observed relative to the vehicle’s lateral motion. For specific muscles, lane changes with the pre-pretensioner belt were associated with earlier muscle activation onsets and significantly smaller activation amplitudes than for the standard belt (P?<?.05).

Conclusions: Applying a pre-pretensioner belt affected muscle activations; that is, amplitude and onset time. The present muscle activation data complement the results in a preceding publication, the volunteers’ kinematics and the boundary conditions from the same data set. An effect of belt configuration was also seen on previously published volunteers’ kinematics with lower lateral and forward displacements for head and upper torso using the pre-pretensioner belt versus the standard belt. The data provided in this article can be used for validation and further improvement of active human body models with active musculature in both sagittal and lateral loading scenarios intended for simulation of some evasive maneuvers that potentially occur prior to a crash.     

Interacting effects of habitat destruction and changing disturbance rates on biodiversity: Who is going to survive?

Changes in disturbance rates due to climate change may increase or decrease diversity, whereas permanent loss of habitat is generally believed to decrease diversity. It is, however, very likely that the effects of disturbances and habitat destruction interact. Understanding such combined effects is essential to predict the response of communities to global changes and in particular which functional types of species are most endangered. Using an individual-based spatially explicit community model, we investigate (1) whether diversity-disturbance curves alter when spatially uncorrelated or autocorrelated habitat destruction is added, and (2) which functional types of species are able to survive under these altered conditions. Model communities consisted of four functional types of species trading off between colonisation ability and competition strength. We found that habitat destruction may alter both height and shape of diversity-disturbance curves: maximum diversity at intermediate disturbance rates may shift to other disturbance rates or even split into two peaks giving rise to bimodal diversity-disturbance relationships with different sub-communities persisting at low and high disturbance rates. Diversity responded differentially depending on how the colonisation-competition trade-off was represented. Our results suggest that, for trade-offs in seed production rate, generally the best coloniser will better withstand the interacting effects of habitat destruction and changing disturbance rates; however, for trade-offs in mean dispersal distances, functional types characterized by intermediate abilities will perform best. We conclude that predictions of the impacts of changing disturbance rates on biodiversity depend on community structure and cannot be made without knowledge of concurrent permanent habitat destruction.     

Spatial segregation of calving and nursing Risso’s dolphins (Grampus griseus) in the Azores,and its conservation implications

Calving can be a critical period for cetaceans. Areas providing security for vulnerable calves, and high food availability for lactating females can be critical habitats requiring specific conservation measures. Here, we test the hypothesis that calving and nursing habitat could be defined for Risso’s dolphins (Grampus griseus). We investigated the spatial and temporal preferences of this species around Pico Island, Azores, using data gathered from land-based surveys and dedicated at-sea observations between 2004 and 2007. We divided observed pods into three groups: (1) those with newborn and young calves, (2) those with older calves or juveniles and (3) those consisting only of adults or sub-adults. We analysed eco-geographical variables and incorporated them into a presence-only spatial distribution model to evaluate differences in habitat suitability among the groups. We identified 694 pods of Risso’s dolphins overall. On the 267 pods observed in the first and second groups, 136 calves or juveniles were identified, of which 22 were newborns. The peak of the calving season was between June and August. The pods with newborn calves were larger and closer to shore, whereas the other groups were more widely dispersed offshore. Our results support the definition of critical habitat areas for this species, but we suggest widening the geographical coverage for better mapping around the island and throughout the archipelago generally. Conservation measures can, nevertheless, be implemented immediately, in order to reduce human impacts on a vulnerable component of the Risso’s dolphin population     

Social status in relation to Sindbis virus infection clearance in greenfinches

The ability to resist infections can differ between individuals of different social rank. This study investigates if the clearance of an avian virus infection (Sindbis virus) was related to the social status of greenfinches (Carduelis chloris) and if infected birds would decline in social status. The results showed that virus clearance patterns were related to social status. Within groups of birds with similar plumage color (a social status signal), body mass and age, a birds social status could be used to predict virus clearance patterns. Dominant birds had higher virus concentrations early in the infection and lower virus titres during later stages of the infection as compared to birds that were subordinates. The infection had no significant effect on previously established social ranks, and ranks that were established during the infection did not appear to be influenced by a birds infection status. In conclusion, this study exemplifies a case where the social rank of an individual was a predictor of the ability to clear a viral infection. The underlying physiological mechanisms of this relationship remain to be further investigated.Communicated by C. Brown     

Heavy gas dispersion by water spray curtains: A research methodology

The mitigation of the consequences of accidental releases of dangerous toxic and/or flammable cloud is a serious concern in the petro-chemical and gas industries. Nowadays, the water-curtain is recognized as a useful technique to mitigate a heavy gas cloud. The paper presents a research methodology, which has been established and undertaken to quantify the forced dispersion factor provided by a water-curtain with respect to its configuration.

The method involves medium-scale field tests, Wind-Gallery tests and numerical simulations. These different approaches are discussed and exemplified by typical results emphasizing the observed concentration reduction due to the water-curtain.     

Life cycle assessment of milk produced in two smallholder dairy systems in the highlands and the coast of Peru

Life Cycle Assessment (LCA) was applied to two smallholder milk production systems in Peru in order to evaluate the environmental burden of milk produced in each. An Andean highland milk production system where livestock feeding is restricted to permanent pastures supplemented with on farm grown ryegrass-clover was opposed to a coastal system with dairy cows fed a diet consisting of fodder maize and purchased concentrate. Milk production levels (kg/cow day) differed considerably with 2.57 for the highland and 19.54 for the coastal system. A Life Cycle Inventory was calculated for the functional unit of 1 kg energy corrected milk (ECM) and the environmental impacts global warming, acidification and eutrophication were estimated for 1 kg ECM, 1 ha and 1 animal, considering the multi-functionality of the system. The highland system was characterized by a high land use (23.1 m²a/kg ECM vs. 1.71 m²a/kg ECM at the coast). Irrigation water and energy were on the other hand used to a much higher amount at the coast (7291 l/kg ECM and 8791 MJ/kg ECM, respectively) than in the highlands (848 l/kg ECM and 0.20 MJ/kg ECM). Global warming potential, acidification and eutrophication were higher for 1 kg ECM produced in the highlands than at the coast by 10.6 kg CO₂ equivalents, 6.58 g sulfur dioxide equivalents and 10.63 g phosphate equivalents, respectively. Nevertheless, 5220 kg CO₂ equivalents more were emitted per animal at the coast than in the highlands. Also acidification and eutrophication were estimated to be on average 6 and 4 times higher at the coast compared to the highlands when expressed for the functional units of 1 ha and 1 animal.

Results

Whereas livestock is mainly responsible for impacts on the environment in the highlands, at the coast both livestock related emissions and forage cultivation play an important role. Furthermore CO₂ releases from soybean cultivations heavily contribute to total emissions. Sensitivity analysis indicates that for dairy systems relying on crop by-products as feed the choice of the allocation method is a crucial point in a LCA study. Based on the results of this study, strategies in order to reduce the environmental burden of milk production should focus on an increase of production levels and a reduction of methane emissions from enteric fermentation in the highlands and a modification of the concentrate components replacing soya as the protein source at the coast.