For polygynous mammals with no paternal care, the number of offspring sired is often the sole measure of male reproductive
success. The potential for polygyny is highest when resources or other environmental factors such as restricted breeding sites
force females to aggregate. In these circumstances, males compete intensely for females and mating success may vary greatly
among males, further intensifying selection for those traits that confer an advantage in reproduction. Hence, determinants
of male success in competition for females are likely to be under strong sexual selection. Paternity analysis was used in
conjunction with measures of age, site fidelity, and behavior during the breeding season to assess variance in male breeding
success in Weddell seals (Leptonychotes weddellii) breeding at Turtle Rock, McMurdo Sound (77.727S, 166.85E) between 1997 and 2000. Paternity could be assigned to 177 pups
at relaxed or 80% confidence level or 111 pups at strict or 95% confidence levels. Weddell seals at Turtle Rock show a modest
degree of polygyny with the greatest number of pups sired by any individual male in a single season equalling 5 or ∼10% of
the pups born. Over four consecutive years, most (89.2%) males sired at least one pup. In a generalized linear model (GLM),
age and the age first seen at the study site as an adult were unrelated to mating success, but adult experience, either site-specific
or elsewhere in McMurdo Sound, over the reproductive life span of males explained nearly 40% of variance in total mating success
with 80% confidence and 24% of variance at 95% confidence. While learning where females are likely to be may enhance male
reproductive success, aquatic mating reduces the ability of males to monopolize females, and thereby increases equity in mating
success. 相似文献
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
Volunteering has long been known for its positive effects on the individual and the community. However, no research to date has examined the safety of individuals when volunteering their services. The safety of individuals when driving a vehicle is particularly a concern in the nonprofit sector as volunteers is leaving organizations due to fear of public liability. As such, this paper aims to identify the internal motivational factors influencing the safety of volunteers when driving a vehicle (n = 73). Utilizing Clary’s et al. [Clary, E.G., Snyder, M., Ridge, R.D., Copeland, J., Stukas, A.A., Haugen, J., Miene, P., 1998. Understanding and assessing the motivations of volunteers: a functional approach. Journal of Personality and Social Psychology 74, 1516–1530] scale of the motivational functions served by volunteering, we found that individuals who volunteer their services for ego-related functioning (protective) were more likely to report higher self-reported driving speeds, while individuals who volunteer their services for altruistic purposes (values) were more likely to report lower self-reported driving speeds. In turn, higher self-reported driving speeds were found to be associated with a greater number of self-reported crashes in the past two years. These results have important implications for volunteer driving organizations, as these results suggest that some motivations are associated with poorer driving performance. 相似文献
Governmental and non-governmental organizations, social movements, and academics have called for reductions in meat consumption due to the environmental, animal welfare, and public health consequences of industrial animal agribusiness. An impactful move toward plant-based diets would require changes in public policy. First, we assess if there are different social and structural factors that influence support for policies that promote plant-based diets. We look at four categories of policies (action frames) that will likely reduce meat consumption: environmental, animal welfare, public health, and direct meat reduction. Second, we use a manipulation rhetorical frame to see if support can be altered by providing individuals with information about meat reduction, framing the issue in terms of environmental protection, animal welfare, or public health. Different social and structural factors predict support for different policy groupings, meaning that it matters how policies are enclosed in action frames. However, providing information to individuals about a particular impact (rhetorical frame) has limited influence on policy support. 相似文献
The HOMINIDS ABM is a new Agent Based Model that simulates the actions of two species of proto-human agents defined by a few, simple parameters. These proto-human agents attempt to subsist by foraging and nesting on dynamic, spatially explicit landscapes. The landscapes are described with a number of parameters based on empirical field data collected in habitats in East Africa. The results of three separate scenarios with 1 year model runs repeated 30 times each, for a total of 90 simulations, are presented and discussed to illustrate both the capacity and flexibility of our ABM modeling environment. The simulations show that the model food preferences and anatomy ascribed to Australopithecus boisei resulted in different expressions of foraging behaviors and subsistence strategies in two distinct ecological settings, and that adding tubers to the diet significantly increases the chances of the hominid agents meeting their daily caloric requirements year-round. In addition, this paper provides links to the open-source implementation code, along with the user documentation, design document, java API, and all datasets required to replicate the simulations. 相似文献
To reduce human casualties associated with explosive ordnance disposal, a wide range of protective wear has been designed to shield against the blast effects of improvised explosive devices and munitions. In this study, 4 commercially available bomb suits, representing a range of materials and armor masses, were evaluated against 0.227 and 0.567 kg of spherical C-4 explosives to determine the level of protection offered to the head, neck, and thorax.A Hybrid III dummy, an instrumented human surrogate [1], was tested with and without protection from the 4 commercially available bomb suits. 20 tests with the dummy torso mounted to simulate a kneeling position were performed to confirm repeatability and robustness of the dummies, as well as to evaluate the 4 suits. Correlations between injury risk assessments based on past human or animal injury model data and various parameters such as bomb suit mass, projected area, and dummy coverage area were drawn. 相似文献
The effect of edible oil emulsion treatment on enhanced reductive dechlorination was evaluated in a 14 month laboratory column study. Experimental treatments included: (1) emulsified soybean oil and dilute HCl to inhibit biological activity; (2) emulsified oil only; (3) emulsified oil and anaerobic digester sludge; and (4) continuously feeding soluble substrate. A single application of emulsified oil was effective in generating strongly reducing, anaerobic conditions for over 14 months. PCE was rapidly reduced to cis-DCE in all three live columns. Bioaugmentation with a halorespiring enrichment culture resulted in complete dechlorination of PCE to ethene in the soluble substrate column (yeast extract and lactate). However, an additional treatment with a pulse of yeast extract and bioaugmentation culture was required to stimulate complete dechlorination in the emulsion treated columns. Once the dechlorinating population was established, the emulsion only column degraded PCE from 90-120 microM to below detection with concurrent ethene production in a 33 day contact time. The lower biodegradation rates in the emulsion treated columns compared to the soluble substrate column suggest that emulsified oil barriers may require a somewhat longer contact time for effective treatment. In the HCl inhibited column, partitioning of PCE to the retained oil substantially delayed PCE breakthrough. However, reduction of PCE to more soluble degradation products (cis-DCE, VC and ethene) greatly reduced the impact of oil-water partitioning in live columns. There was only a small decline in the hydraulic conductivity (K) of column #1 (low pH+emulsion, K(final)/K(initial)=0.57) and column #2 (live+emulsion, K(final)/K(initial)=0.73) indicating emulsion injection did not result in appreciable clogging of the clayey sand. However, K loss was greater in column #3 (sludge+emulsion, K(final)/K(initial)=0.12) and column #4 (soluble substrate, K(final)/K(initial)=0.03) indicating clogging due to biomass and/or gas production can be significant. 相似文献
Soils bind heavy metals according to fundamental physico-chemical parameters. Bioassays, using bacterial biosensors, were performed in pore waters extracted from 19 contrasting soils individually amended with Cd, Cu and Zn concentrations related to the EU Sewage Sludge Directive. The biosensors were responsive to pore waters extracted from Zn amended soils but less so to those of Cu and showed no toxicity to pore water Cd at these environmentally relevant amended concentrations. Across the range of soils, the solid-solution heavy metal partitioning coefficient (K(d)) decreased (p<0.01) with increasing amendments of Cu and Zn; Cu exhibited the highest K(d) values. Gompertz functions of Cu and Zn, K(d) values against luminescence explained the relationship between heavy metals and biosensors. Consequently, biosensors provide a link between biologically defined hazard assessments of metals and standard soil-metal physico-chemical parameters for determining critical metal loadings in soils. 相似文献