Objective: This article aims to describe seat belt wearing patterns and quality of seat belt fit among drivers aged 75 years and older. A secondary aim is to explore associations between body shape, comfort, and seat belt use patterns.
Methods: This is an observation and survey study of a cohort of 380 drivers aged 75 years and over. During home visits, photographs were taken of the drivers in their vehicles for later analysis of belt fit and a short survey was also administered to collect demographic data and information about seat belt use and comfort. Seat belt fit and use of belt and seat accessories were analyzed from the photographs.
Results: Data from 367 participants with photographs were analyzed. Whereas 97% reported using a seat belt and 90% reported their seat belt to be comfortable, 21% reported repositioning their seat belt to improve comfort. Good sash and lap belt fit were achieved in 53 and 59% of participants, respectively, but only 35% achieved overall good fit. Both poor sash and lap belt fit were observed in 23% of participants. Drivers who were in the obese category had over twice the odds (95% confidence interval [CI], 1.2–4.1) of having a poor lap belt fit than those in the normal body mass index [BMI] range, and drivers who were overweight had 1.8 times the odds (95% CI, 1.1–2.9) of having poor lap belt fit. Older females also had twice the odds (95% CI, 1.3–3.5) of poor lap belt fit compared to older males, regardless of BMI. Sash belt fit did not vary significantly by BMI, stature, or gender. However older drivers who reported that they had not made any adjustments to the D-ring height had 1.7 times the odds of having poor sash belt fit than those who made adjustments (1.2–2.9). Females were 7.3 times more likely to report comfort problems than males (95% CI, 3.2, 16.3) but there was no association between reported comfort and BMI or seat belt fit. Drivers who reported comfort problems had 6 times the odds (3.2–13.6) of also reporting active repositioning of the belt.
Conclusions: The results suggest that older drivers face challenges in achieving comfortable and correct seat belt fit. This may have a negative impact on crash protection. Belt fit problems appear to be associated with body shape, particularly high BMI and gender. There is a need for further investigation of comfort accessories; in the interim, older drivers and occupants should be encouraged to use features such as D-ring adjusters to improve sash belt fit. 相似文献
Rare, small or annual vegetation species are widely known to be imperfectly detected with single site surveys by most conventional
vegetation survey methods. However, the detectability of common, persistent vegetation species is assumed to be high, but
without supporting research. In this study, we evaluate the extent of false-negative errors of perennial vegetation species
in a systematic vegetation survey in arid South Australia. Analysis was limited to the seven most easily detected persistent
vegetation species and controlled for observer skill. By comparison of methodologies, we then predict the magnitude of non-detection
error rates in a second survey. The analysis revealed that all but one highly detectable perennial vegetation species was
imperfectly detected (detection probabilities ranged from 0.22 to 0.83). While focussed in the Australian rangelands, the
implications of this study are far reaching. Inferences drawn from systematic vegetation surveys that fail to identify and
account for non-detection errors should be considered potentially flawed. The identification of this problem in vegetation
surveying is long overdue. By comparison, non-detection has been a widely acknowledged, and dealt with, problem in fauna surveying
for decades. We recommend that, where necessary, vegetation survey methodology adopt the methods developed in fauna surveying
to cope with non-detection errors. 相似文献
According to the United States Department of Transportation (USDOT), more than 3.1 billion tons of hazardous materials (HazMat) are shipped within the United States annually. This averages to about 800,000 individual shipments of HazMat per day, of which 300,000 are shipments of petroleum/flammable–combustible liquids. This paper presents a temporal trend study (1995–2004) of 2145 HazMat incidents occurring through the transportation of flammable/combustible liquids. The study also correlates between HazMat incidents and distances between shipment origin and incident location. These distances attained through great circle calculations since the data compilation did not allow for the identification of specific routes taken in commodity transport. Findings of this study illustrate a bimodal distribution of frequency as a function of the logarithm of the Distance with first mode (less than 105 miles) mean of 24 [km] and second mode mean of 1061 [km]. Additionally, transport phase introduced no significance to the distribution of frequencies. 相似文献
The conversion of natural habitat to urban settlements is a primary driver of biodiversity loss, and species' persistence is threatened by the extent, location, and spatial pattern of development. Urban growth models are widely used to anticipate future development and to inform conservation management, but the source of spatial input to these models may contribute to uncertainty in their predictions. We compared two sources of historic urban maps, used as input for model calibration, to determine how differences in definition and scale of urban extent affect the resulting spatial predictions from a widely used urban growth model for San Diego County, CA under three conservation scenarios. The results showed that rate, extent, and spatial pattern of predicted urban development, and associated habitat loss, may vary substantially depending on the source of input data, regardless of how much land is excluded from development. Although the datasets we compared both represented urban land, different types of land use/land cover included in the definition of urban land and different minimum mapping units contributed to the discrepancies. Varying temporal resolution of the input datasets also contributed to differences in projected rates of development. Differential predicted impacts to vegetation types illustrate how the choice of spatial input data may lead to different conclusions relative to conservation. Although the study cannot reveal whether one dataset is better than another, modelers should carefully consider that geographical reality can be represented differently, and should carefully choose the definition and scale of their data to fit their research objectives. 相似文献
Life-history characteristics exert a profound influence upon the population structure of many marine organisms. However, relatively
few genetic studies have compared direct with indirect-developing species in the same ecosystem or geographical region, and
none to our knowledge within an Antarctic setting. To address this issue, we have collected novel amplified fragment length
polymorphism (AFLP) data from the direct-developing top shell Margarella antarctica to form a comparison with previously published data for the broadcast-spawning Antarctic limpet Nacella concinna. We scored 270 loci in 240 M. antarctica individuals sampled from five populations spanning the full length of the Antarctic Peninsula. Profound differences were
identified in the strength and pattern of population structure between the two species, consistent with gene flow being highly
restricted in M. antarctica relative to N. concinna. 相似文献
Many important ecological phenomena depend on the success or failure of small introduced populations. Several factors are thought to influence the fate of small populations, including resource and habitat availability, dispersal levels, interspecific interactions, mate limitation, and demographic stochasticity. Recent field studies suggest that Allee effects resulting from mate limitation can prevent the reestablishment of sexual zooplankton species following a disturbance. In this study, we explore the interplay between Allee effects and local environmental conditions in determining the population growth and establishment of two acid-sensitive zooplankton species that have been impacted by regional anthropogenic acidification. We conducted a factorial design field experiment to test the impact of pH and initial organism densities on the per capita population growth (r) of the sexual copepod Epischura lacustris and the seasonally parthenogenetic cladoceran Daphnia mendotae. In addition, we conducted computer simulations using r values obtained from our experiments to determine the probability of extinction for small populations of acid-sensitive colonists that are in the process of colonizing recovering lakes. The results of our field experiment demonstrated that local environmental conditions can moderate the impacts of Allee effects for E. lacustris: Populations introduced at low densities had a significantly lower r at pH 6 than at pH 7. In contrast, r did not differ between pH 6 and 7 environments when E. lacustris populations were introduced at high densities. D. mendotae was affected by pH levels, but not by initial organism densities. Results from our population growth simulations indicated that E. lacustris populations introduced at low densities to pH 6 conditions had a higher probability of extinction than those introduced at low densities to a pH 7 environment. Our study indicates that environmental conditions and mate limitation can interact to determine the fate of small populations of sexually reproducing zooplankton species. If a more rapid recovery of acid-damaged zooplankton communities is desired, augmentation of dispersal levels may be needed during the early phases of pH recovery in order to increase the probability of establishment for mate-limited zooplankton species. 相似文献