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1.
Boufous and Olivier (2015) recently found an increasing trend of police-reported cyclist deaths in single-vehicle crashes while a decreasing trend was found for fatal bicycle-motor vehicle crashes. This study sets out to conduct the same trend analyses for the Netherlands using causes of death statistics. The results show that for 1996–2014, the number of cyclist deaths in motor vehicle collisions per km cycled (i.e. the risk) has declined by 3.8% per annum (95% CI: −4.6%, −3.0%) while the risk of cyclist deaths in crashes without motor vehicles increased by 7.0% per annum (95% CI: 5.5%, 8.7%). The large majority of cyclist deaths at the beginning of the study period were due to bicycle-motor vehicle crashes. By 2014, however, the share with motor vehicles was only slightly higher than the share without motor vehicles. We also conducted trend analyses controlling for age by stratifying into nine age groups. After controlling for age, the average annual decrease of cyclist deaths in crashes with motor vehicles was 5.4% (95% CI: −6.0% to  4.7%). The average annual increase of deaths in crashes without motor vehicles was 4.4% (95% CI: 3.1–5.7%). These trends are more favourable than those without controlling for age which can be explained by more cycling among the elderly who have an elevated risk. We conclude that, similar to Australia, cyclist deaths following motor vehicle crashes in the Netherlands have decreased while deaths without motor vehicles have increased.  相似文献   

2.
Stationary and moving surfaces impose different constraints on walking. In this study we investigated within-participants differences between walking on a ship before (at the dock) and during (at sea) a sea voyage. Four individuals participated in the study. While on the ship they wore a tri-axial accelerometer (ActiGraph GT3X+; ActiGraph LLC, Pensacola, FL) on their waists. Activity data were sampled at 30 Hz. Data were collected on the day before the voyage began and on several days at sea. The number of steps per day was greater at the dock than at sea. The net resultant force per day also was greater at the dock than at sea. However, resultant force per step was greater at sea (79.97 ± 8.50 vector magnitude counts/step) than on land (62.94 ± 10.03 vector magnitude counts/step). In addition, we observed variations in resultant force per step across days at sea. Ship motion decreased overall activity but increased the force per step.  相似文献   

3.
A standard objection to a market in political votes is that it will enable the rich politically to dominate the poor. If a market in votes was allowed then the poor would be the most likely sellers and the rich the most likely buyers. The rich would thus accumulate the votes of the poor, and so the candidates elected and the policies passed would represent only their interests and not those of the electorate as a whole. To ensure that the poor do not become de facto disenfranchised, then, markets in votes should be disallowed. This objection seems so straightforward and compelling that it has received almost no critical scrutiny. This is unfortunate, for close examination reveals that this argument is not as straightforward as it initially appears. Indeed, there are (at least) four different ways of understanding this objection. It could be understood as expressing: (1) the concern that markets in votes would enable candidates to win elections who would otherwise lose them; (2) the concern that they would enable the election of candidates opposed by the majority of the electorate; (3) the concern that they would lead to the poor having disproportionately low political influence; and (4) the concern that they would lead to the rich having disproportionately high political influence. I will argue in this paper that only (3) and (4) could plausibly ground objections to markets in votes. Moreover, these will only plausibly ground objections to unrestricted markets in votes; they will not ground objections to markets in votes per se. Thus, if we are to continue to object to markets in political votes we will have to do this on grounds other than that were they to be allowed the rich will politically dominate the poor.  相似文献   

4.
Comparative evolutionary psychology of sperm competition   总被引:3,自引:0,他引:3  
A comparative evolutionary psychological perspective predicts that species that recurrently faced similar adaptive problems may have evolved similar psychological mechanisms to solve these problems. Sperm competition provides an arena in which to assess the heuristic value of such a comparative evolutionary perspective. The sperm competition that results from female infidelity and polyandry presents a similar class of adaptive problems for individuals across many species. The authors first describe mechanisms of sperm competition in insects and in birds. They suggest that the adaptive problems and evolved solutions in these species provide insight into human anatomy, physiology, psychology, and behavior. The authors then review recent theoretical and empirical arguments for the existence of sperm competition in humans and discuss proposed adaptations in humans that have analogs in insects or birds. The authors conclude by highlighting the heuristic value of a comparative evolutionary psychological approach in this field.  相似文献   

5.
This article examines the statistical determinants of risk preference. In a meta-analysis of animal risk preference (foraging birds and insects), the coefficient of variation (CV), a measure of risk per unit of return, predicts choices far better than outcome variance, the risk measure of normative models. In a meta-analysis of human risk preference, the superiority of the CV over variance in predicting risk taking is not as strong. Two experiments show that people's risk sensitivity becomes strongly proportional to the CV when they learn about choice alternatives like other animals, by experiential sampling over time. Experience-based choices differ from choices when outcomes and probabilities are numerically described. Zipf's law as an ecological regularity and Weber's law as a psychological regularity may give rise to the CV as a measure of risk.  相似文献   

6.
We studied the influence of ship motion on postural activity during stance, varying stance width (the distance between the feet in side-by-side stance) and the difficulty of visual tasks. Participants (experienced crewmembers) were tested on land and then on successive days on a ship at sea in mild sea states. On land, we replicated classical effects of stance width and visual task on the magnitude of postural movement. The magnitude of forces used in postural control was greater at sea than on land. Visual performance at sea was comparable to performance on land. Both stance width and visual task difficulty influenced postural activity at sea. In addition, postural activity changed over days at sea. We conclude that experienced crewmembers modulated standing posture in support of the performance of visual tasks and that such effects occurred even in mild sea states. The overall pattern of effects is compatible with the hypothesis that postural activity is modulated, in part, in support of the performance of suprapostural tasks.  相似文献   

7.
Microcredit is often hailed as an effective way of alleviating poverty. In recent years, however, microfinance institutions have been the target of much criticism due to their comparatively high interest rates (which may be as high as 70–100% per annum). This paper discusses whether it can be morally justified to charge very high rates of interest when lending money to the poor. Arguments are drawn from contemporary as well as historical debates on usury, exploitation, egalitarianism and consequentialism. It is conceded that it would be preferable if interest rates could be reduced, but it is argued that typical microlenders today do nothing wrong in setting their rates at the current levels. Instead the responsibility rests on governments, commercial banks and overseas investors to facilitate an environment where rates could be reduced.  相似文献   

8.
Motion of a ship at sea creates challenges for control of the body. Anecdotal reports suggest that the body can be stabilized by standing on the open deck and looking at the horizon. This advice contrasts with land-based findings that looking at the horizon leads to increased body sway. We measured standing body sway in experienced maritime crew members on land and at sea. On land, body sway was greater when subjects looked at the horizon than when they did not-the classical effect. At sea, body sway was greater in a closed cabin than on the open deck. On the open deck, body sway when looking at the horizon was reduced relative to sway when looking at middistance targets on the ship. The results are consistent with centuries of anecdotal advice given to sea travelers and raise new questions about the referents that are used for the control of standing posture.  相似文献   

9.
This study examined the social reaction pathway of the Prototype Willingness Model (PWM) to assess how attitudes, subjective norms, prototype perception (favourability and similarity), and risk perception influenced young passengers’ willingness to speak up to a driver exceeding the posted speed limit by either 5 km/h or 10 km/h. It was hypothesised that participants would be more willing to speak up to drivers’ travelling 10 km/h over the posted speed limit than 5 km/h over the posted speed limit. Further, it was hypothesised that the PWM constructs would significantly predict passenger willingness to speak up to a driver travelling 5 km/h over the posted speed limit and 10 km/h over the posted speed limit. Young Australians aged 17 to 25 years (N = 136, Mage = 19.32, 77.9% female) were recruited to complete a 30-minute online questionnaire. As predicted, passengers were significantly more willing to speak up to drivers travelling at 10 km/h over the posted speed limit than drivers travelling 5 km/h over the posted speed limit. Further, the results from a linear regression revealed that some of the PWM constructs were effective in explaining the variance in willingness to speak-up to drivers travelling either 5 km/h or 10 km/h over the posted speed limit. These findings address a gap in road safety research by shifting focus from the behaviour of drivers to the behaviour of passengers. The focus on the pro-social behaviour of speaking up to drivers performing risk taking behaviours may help to inform future educational campaigns and interventions designed to reduce young peoples’ involvement in road crashes.  相似文献   

10.
Defensive aggression was examined in seven species of terns during the hatching period when young are most vulnerable and adults most responsive. Aggression toward an unfamiliar person varied with respect to species, flush distance, approach distance, number of birds overhead and diving, and number of dives per 2 min for all birds and the nest owner. Defensive aggression involved birds circling over and diving at the experimenter. Generally, flush distance was negatively correlated with nest density, while the number of birds diving was positively correlated with the nest density. The number of birds diving was positively related to the number of dives, dives by the owner, and the number overhead.  相似文献   

11.
Alloxan-diabetic rats were hyperphagic when fed diets containing little fat, but they ate normal amounts of food when given diets rich in fat. Normal rats increased food intake to the same degree when the caloric density of their diet was decreased by reducing the content of fats or carbohydrates in isocaloric amounts. Diabetic rats did not respond substantially to changes in caloric density of their diet which were produced by altering the content of dietary carbohydrates, but they systematically increased food intake as the amount of fat in their diet was reduced. Diabetic rats ate normal amounts of a high-fat diet despite continued loss of nutrients in urine and persisting impairments in glucose utilization, fat storage, and liver glycogen deposition. These findings suggest that hyperphagia in experimental diabetes mellitus is a compensatory response to a lack of utiliziable fat fuels rather than the result of a metabolic disturbance per se.  相似文献   

12.
Three experiments investigated how the frequency of exposure to particular exemplars influenced 10-month-old infants' differentiation of land and sea animals in an object-examining task. In Experiments 1 and 2, one category exemplar was presented more frequently than the others during familiarization (i.e., that exemplar was presented on 6 of 12 familiarization trials, and 3 other exemplars were each presented on 2 familiarization trials). For half of the infants, the frequent exemplar was similar to other category exemplars (e.g., a zebra if the familiarization category was land animals), and for half the frequent exemplar was not similar to many other category exemplars (e.g., a rabbit). Infants who frequently experienced the similar exemplar formed an exclusive category, and differentiated land and sea animals. Infants who frequently experienced a dissimilar exemplar, in contrast, formed an inclusive category, and failed to differentiate between land and sea animals. In Experiment 3, infants received frequent experience with a set of similar or dissimilar exemplars, and the same pattern was observed. Thus, 10-month-old infants are sensitive to the distribution of the exemplars to which they are exposed, and they form different category boundaries depending on that distribution.  相似文献   

13.
Journalists and media assistants in many places are murdered, imprisoned, censored, threatened, and similarly harrassed. Here I document that, and explain why, there are three climato‐economic niches of press repression versus press freedom as part of broader syndromes of national culture. A 175‐nation coding of documents by scientific analysts, survey responses from top executives in 123 countries, and participative observations by journalists in 155 countries led to basically the same findings. Cultures of press repression, survival values, and collectivism are most prevalent in poor countries with demanding cold or hot climates. Cultures of press freedom, self‐expression values, and individualism are most prevalent in rich countries with demanding cold or hot climates. Intermediate cultures are most prevalent in poor and rich countries with temperate climates. Rival explanations in terms of a country's historic roots, population diversity, and societal inequality are ruled out and discussed.  相似文献   

14.
The triple disaster of March 11, 2011 posed a formidable challenge for Japanese society in general, and for affected coastal communities in particular. In the immediate aftermath of the catastrophe, there was widespread support for the construction of high seawalls to protect communities. However, many communities began questioning this approach. In Maehama, the question of land reconstruction and protection gave rise to a set of complex responses. The government aimed to put in place even higher seawalls; however, the local community proposed instead to mark the boundary of high water with trees and stakes. These solutions instantiate different ways of infrastructuring the post-tsunami environment for safety; they carry different assumptions about infrastructure itself. Whereas the seawall solution was technical and quantitative, centering on the question of height, the boundary markers embedded qualitatively different assumptions about what makes a workable infrastructure. In particular, this difference centered on issue of visibility. On the one hand, the seawall was meant to slowly become unremarkable, whereas the boundary markers were specifically intended to maintain community memory. On the other hand, the seawall would make the sea itself invisible, whereas keeping the sea in sight is very important to villagers. However, the opposition between these forms of infrastructuring the environment was not total. A solution was gradually negotiated in which the sea wall and the boundary markers could complement each another. This situation highlights the intricate, transformable relation between visible and invisible forms of infrastructure.  相似文献   

15.
Darwin's notes from the Beagle period abound with observations on animal behavior. Although in places anecdotal and anthropomorphic, they include many detailed, lively comments of the activities of birds, reptiles, mammals, Crustacea, insects, and other invertebrates. In his comparative approach, belief in the importance of heredity, an understanding that behavior might be of assistance in taxonomy, and that it was linked with both the organism's morphology and habitat, and his attempts at experiments, Charles Darwin in his early and mid-twenties was using techniques and concepts that were to be of great significance in his later work.  相似文献   

16.
17.
Studies of acoustic interactions in animal groups, such as chorusing insects, anurans, and birds, have been invaluable in showing how cooperation and competition shape signal structure and use. The begging calls of nestling birds are ideal for such studies, because they function both as a cooperative signals of the brood's needs and as competitive signals for parental allocation within the brood. Nonetheless, studies of acoustic interactions among nestlings are rare. Here we review our work on acoustic interactions in nestling tree swallows (Tachycineta bicolor), especially how calls are used in competition for parental feedings. Nestlings attracted parental attention and responded to acoustic interference mainly by increasing call output. However, nestlings also gave more similar calls when they called together and decreased their call bandwidth when exposed to elevated noise. We suggest that these competitive uses of calls might intensify the cooperative brood signal, affecting both parental provisioning and vocal development. Given their tremendous variation across species, begging calls offer promising opportunities for developmental and comparative studies of acoustic signaling.  相似文献   

18.
Based on Finnish survey data, older (65+, n=1559) and younger (26–40, n=310) drivers’ accident rates were compared. In accordance with earlier studies, the rates were similar per driver (0.1) but there was a non-significant trend towards older drivers having more accidents per distance driven (10.8 vs. 8.3 per 1 million km). However, when the accidents-per-km comparison was made in groups matched for yearly exposure, there is no evidence for higher risk with increasing age. In both age groups, risk per km decreased with increasing yearly driving distance. We suggest that the previous perception of an age-related risk increase of accidents per distance driven arises from a failure to control for low mileage bias at all ages.  相似文献   

19.
The visual acuity of the pigeon for distant targets   总被引:3,自引:2,他引:1       下载免费PDF全文
The acuity of six pigeons was measured in an apparatus that required the birds to make visual discriminations at a distance of 28.75 in. (73 cm) from the stimulus targets. The stimuli were black and white gratings of varying stripe width. A forced choice procedure was used, and both the Method of Constant Stimuli and a descending series technique determined the order of stimulus presentation. Thresholds, obtained by interpolating at the 25% error point on the psychometric functions, ranged from 1.16 to 4.0 min of arc. Thresholds measured in the same apparatus for two human observers were 0.79 and 0.82 min of arc. The descending series design produced lower per cent error rates at the widest stripe value, but otherwise there appeared to be no difference between psychophysical methods. Position preferences occurred in most of the birds; differential per cent error functions and differential latency functions to the two keys illustrate these. Retinal histology revealed shallow, centrally located foveae in the three pigeon breeds used.  相似文献   

20.
Time-space learning reflects an ability to represent in memory event-stimulus properties together with the place and time of the event; a capacity well developed in birds. Homing pigeons were trained in an indoor octagonal arena to locate one food goal in the morning and a different food goal in the late afternoon. The goals differed with respect to their angular/directional relationship to an artificial light source located outside the arena. Further, the angular difference in reward position approximated the displacement of the sun's azimuth that would occur during the same time period. The experimental birds quickly learned the task, demonstrating the apparent ease with which birds can adopt an artificial light source to discriminate among alternative spatial responses at different times of the day. However, a novel midday probe session following successful learning revealed that the light source was interpreted as a stable landmark and not as a surrogate sun that would support compass orientation. Probe sessions following a phase shift of the light–dark cycle revealed that the mechanism employed to make the temporal discrimination was prevailingly based on an endogenous circadian rhythm and not an interval timing mechanism.  相似文献   

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