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1.
In a study of the ambulance service to an outpatient physiotherapy centre in an urban area over half of the palients were aged over 65, a quarter made at least three visits to the centre weekly, and the average travel and waiting times for all patients was about two-and-a-half hours. There was a direct relation between distance from home to the centre and travelling time for morning but not afternoon attenders. A second survey after some changes in the transport arrangements showed some relatively small reductions in overall travelling and waiting time. It is concluded that even under favourable conditions an important side effect of outpatient physiotherapy is the probable fatigue and anxiety generated by ambulance travel.  相似文献   

2.
Pollinating bees develop foraging circuits (traplines) to visit multiple flowers in a manner that minimizes overall travel distance, a task analogous to the travelling salesman problem. We report on an in-depth exploration of an iterative improvement heuristic model of bumblebee traplining previously found to accurately replicate the establishment of stable routes by bees between flowers distributed over several hectares. The critical test for a model is its predictive power for empirical data for which the model has not been specifically developed, and here the model is shown to be consistent with observations from different research groups made at several spatial scales and using multiple configurations of flowers. We refine the model to account for the spatial search strategy of bees exploring their environment, and test several previously unexplored predictions. We find that the model predicts accurately 1) the increasing propensity of bees to optimize their foraging routes with increasing spatial scale; 2) that bees cannot establish stable optimal traplines for all spatial configurations of rewarding flowers; 3) the observed trade-off between travel distance and prioritization of high-reward sites (with a slight modification of the model); 4) the temporal pattern with which bees acquire approximate solutions to travelling salesman-like problems over several dozen foraging bouts; 5) the instability of visitation schedules in some spatial configurations of flowers; 6) the observation that in some flower arrays, bees'' visitation schedules are highly individually different; 7) the searching behaviour that leads to efficient location of flowers and routes between them. Our model constitutes a robust theoretical platform to generate novel hypotheses and refine our understanding about how small-brained insects develop a representation of space and use it to navigate in complex and dynamic environments.  相似文献   

3.
4.
Modification of dispersal behaviour is a common response of insects to food and water deprivation. The literature suggests that different insects respond with different strategies: changing walking parameters, switching dispersal mode (walking to flight or vice versa), or changing the host searching path. The goal of this study was to add to the limited literature on the subject by investigating, whether the walking parameters of adult male Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), change in response to food and water deprivation. Observations on the distance walked, the travel speed, and the frequency of walking bouts were carried out in laboratory arenas using motion monitoring equipment. Summer and overwintered beetles were exposed to short starvation periods (2, 4, 8, 24 h) and two ranges of long starvation periods (1, 2, 4, 8 days and 1, 2, 4, 8, 16, and 32 days). Only the longest food deprivation periods of 16 and 32 days significantly reduced the walking distance, speed, and frequency of walking bouts of summer beetles. No changes were observed with overwintered beetles. The tolerance of the beetles without access to water to the different periods of food deprivation was similar to that for beetles with water except after a starvation period of 32 days, when the travel speed of summer beetles was significantly reduced by 33%. The absence of increased walking parameters found in this study and earlier observations of increased flight frequency suggest that the strategy of summer beetles will be to change the dispersal mode from walking to flight and/or to change the walking host searching path. The same results of this study and earlier observations of a decrease in the mean frequency of daily flights suggest that the strategy of overwintered L. decemlineata, exposed to food deprivation, will be to change the host search walking path rather than the walking parameters themselves.  相似文献   

5.
Search tactics are explored for animals hunting randomly distributed prey in two-dimensional habitats. The predator chooses between two modes of search: continuous travel and alternating pause-travel. A model based on renewal processes is derived for the predator's net rate of energy intake. The model is used to explore the optimal mode of search, search height, pause duration (“giving-up time”) and move length. Energy expenditure for search is assumed to increase from perchtravel over continuous travel to hover-travel. Prey detectability is assumed to be higher for the pausing than for the travelling predator. The following predictions emerge: The relative merits of the different search modes are mainly determined by the relative magnitudes of energy consumption rates and prey detection efficiencies at pausing and travelling. The energetically cheaper among two search modes reaches its highest relative merit at low prey density and detectability. As either increases, a more expensive search tactic may become superior. If the rate of energy expenditure increases considerably at locomotion, pause-travel tactics may be superior to continuous travel. This requires that the search can be performed from sufficient height, because net energy gain decreases rapidly below the optimum search height. It is greater for pause-travel than for continuous travel, and it increases slightly with decreasing prey density, and markedly with increasing prey detectability. With perch-travel or hover-travel tactics, the optimal giving-up time decreases with increasing prey density and detectability. The optimal move length increases with detectability. Empirical evidence coincides qualitatively with several predictions. Possibilities for further tests of the model are discussed, as are observed behavioural and morphological features on which the search model may shed light.  相似文献   

6.
We studied the long‐distance migration of Lesser Black‐backed Gulls Larus fuscus fuscus breeding in northern Norway along their eastern flyway using geolocators in 2009 and 2010. The majority of birds wintered in lakes in East Africa and the southeast Mediterranean was the most important stopover area. Larus f. fuscus along the eastern flyway travelled at a net travel speed of 399 and 177 km/day during the autumn and spring migration, respectively, higher than published travel speeds for Dutch Larus fuscus migrating along the western flyway. The results suggest that the long‐distance migratory Norwegian L. f. fuscus seek to minimize time spent in transit, whereas lower travel speed during northerly spring migration may reflect differences in wind patterns or food conditions between spring and autumn.  相似文献   

7.
Research has shown that individuals have an optimal walking speed–a speed which minimizes energy expenditure for a given distance. Because the optimal walking speed varies with mass and lower limb length, it also varies with sex, with males in any given population tending to have faster optimal walking speeds. This potentially creates an energetic dilemma for mixed-sex walking groups. Here we examine speed choices made by individuals of varying stature, mass, and sex walking together. Individuals (N = 22) walked around a track alone, with a significant other (with and without holding hands), and with friends of the same and opposite sex while their speeds were recorded every 100 m. Our findings show that males walk at a significantly slower pace to match the females’ paces (p = 0.009), when the female is their romantic partner. The paces of friends of either same or mixed sex walking together did not significantly change (p>0.05). Thus significant pace adjustment appears to be limited to romantic partners. These findings have implications for both mobility and reproductive strategies of groups. Because the male carries the energetic burden by adjusting his pace (slowing down 7%), the female is spared the potentially increased caloric cost required to walk together. In energetically demanding environments, we will expect to find gender segregation in group composition, particularly when travelling longer distances.  相似文献   

8.
 A spatially explicit integrodifference equation model is studied for the spread of an invading organism against an established competitor. Provided the invader is initially confined to a bounded region, the invasion spreads asymptotically as a travelling wave whose speed depends on the strength of the competitive interaction and on the dispersal characteristics of the invader. Even an inferior, but established, competitor can significantly reduce the invasion speed. The invasion speed is also influenced by the exact shape of the dispersal kernel (especially the thickness of the tail) as well as the mean dispersal distance for each generation. Received 10 April 1996; received in revised form 21 August 1996  相似文献   

9.

Background

Official reports on modal risk have not chosen appropriate numerators and denominators to enable like-for-like comparisons. We report age- and sex-specific deaths and injury rates from equivalent incidents in England by travel mode, distance travelled and time spent travelling.

Methods

Hospital admissions and deaths in England 2007–2009 were obtained for relevant ICD-10 external codes for pedestrians, cyclists, and car/van drivers, by age-group and sex. Distance travelled by age-group, sex and mode in England (National Travel Survey 2007–2009 data) was converted to time spent travelling using mean trip speeds. Fatality rates were compared with age-specific Netherlands data.

Results

All-age fatalities per million hours’ use (f/mhu) varied over the same factor-of-three range for both sexes (0.15–0.45 f/mhu by mode for men, 0.09–0.31 f/mhu for women). Risks were similar for men aged 21–49 y for all three modes and for female pedestrians and drivers aged 21–69 y. Most at risk were: males 17–20 y (1.3 f/mhu (95% CI 1.2–1.4)) for driving; males 70+ (2.2 f/mhu(1.6–3.0)) for cycling; and females 70+ (0.95 f/mhu (0.86–1.1)) for pedestrians. In general, fatality rates were substantially higher among males than females. Risks per hour for male drivers <30 y were similar or higher than for male cyclists; for males aged 17–20 y, the risk was higher for drivers (33/Bn km (30–36), 1.3 f/mhu (1.2–1.4)) than cyclists (20/Bn km (10–37), 0.24 f/mhu (0.12–0.45)) whether using distance or time. Similar age patterns occurred for cyclists and drivers in the Netherlands. Age-sex patterns for injuries resulting in hospital admission were similar for cyclists and pedestrians but lower for drivers.

Conclusions

When all relevant ICD-10 codes are used, fatalities by time spent travelling vary within similar ranges for walking, cycling and driving. Risks for drivers were highest in youth and fell with age, while for pedestrians and cyclists, risks increased with age. For the young, especially males, cycling is safer than driving.  相似文献   

10.
In a predator–prey system, prey species may adapt to the presence of predators with behavioral changes such as increased vigilance, shifting habitats, or changes in their mobility. In North America, moose (Alces alces) have shown behavioral adaptations to presence of predators, but such antipredator behavioral responses have not yet been found in Scandinavian moose in response to the recolonization of wolves (Canis lupus). We studied travel speed and direction of movement of GPS‐collared female moose (n = 26) in relation to spatiotemporal differences in wolf predation risk, reproductive status, and time of year. Travel speed was highest during the calving (May–July) and postcalving (August–October) seasons and was lower for females with calves than females without calves. Similarly, time of year and reproductive status affected the direction of movement, as more concentrated movement was observed for females with calves at heel, during the calving season. We did not find support for that wolf predation risk was an important factor affecting moose travel speed or direction of movement. Likely causal factors for the weak effect of wolf predation risk on mobility of moose include high moose‐to‐wolf ratio and intensive hunter harvest of the moose population during the past century.  相似文献   

11.

Background

Travel to school may offer a convenient way to increase physical activity levels in childhood. We examined the association between method of travel to school and physical activity levels in urban multi-ethnic children.

Methods and Findings

2035 children (aged 9–10 years in 2006–7) provided data on their usual method of travel to school and wore an Actigraph-GT1M activity monitor during waking hours. Associations between method of travel and mean level of physical activity (counts per minute [CPM], steps, time spent in light, moderate or vigorous activity per day) were examined in models adjusted for confounding variables. 1393 children (69%) walked or cycled to school; 161 (8%) used public transport and 481 (24%) travelled by car. White European children were more likely to walk/cycle, black African Caribbeans to travel by public transport and South Asian children to travel by car. Children travelling by car spent less time in moderate to vigorous physical activity (−7 mins, 95%CI-9,-5), and had lower CPM (−32 CPM, 95%CI-44,-19) and steps per day (−813 steps, 95%CI,-1043,-582) than walkers/cyclists. Pupils travelling by public transport had similar activity levels to walkers/cyclists. Lower physical activity levels amongst car travellers'' were especially marked at travelling times (school days between 8–9 am, 3–5 pm), but were also evident on weekdays at other times and at weekends; they did not differ by gender or ethnic group.

Conclusion

Active travel to school is associated with higher levels of objectively measured physical activity, particularly during periods of travel but also at other times. If children travelling by car were to achieve physical activity levels (steps) similar to children using active travel, they would increase their physical activity levels by 9%. However, the population increase would be a modest 2%, because of the low proportion of car travellers in this urban population.  相似文献   

12.
The aim of this study was to investigate the effects of a static magnetic field on six behavioral parameters (travel distance, average speed while in motion, travel distance of the head, body rotations, time in movement, and immobility time) of the ground beetle Laemostenus (Pristonychus) punctatus (Dejean) (Coleoptera: Carabidae). Adults of this troglophilic and guanophilic beetle were randomly divided into two groups, the first exposed to a static magnetic field of 110 mT for 5 h, and the second a control group. Beetle behavior after these 5 h was monitored in an open‐field test for 12 min and analyzed using ANY‐maze software. Exposure to a static magnetic field of 110 mT increased motor activity (travel distance and average speed while in motion) in the first 4 min. After that there were no significant differences. We conclude that the applied static magnetic field affects motor activity of adult specimens of L. (P.) punctatus, and we discuss the mechanism, possibly through acting on the control centers responsible for orientation and movement.  相似文献   

13.
The detailed habitat utilization of the Shiga B2 troop was studied in winter. The following results were obtained. (1) The roosting site distribution was limited to the Yokoyugawa valley. (2) The measured home range size was 1.99 km2, which was greater than the 1.23 km2 of larger population size of the Shiga C troop. (3) The daily travel distance ranged from 0 to 1,825 m (mean 646 m). (4) The pendulum cycle of troop movement is composed of two types: wandering and tripping. The daily travel distance in tripping was much longer than that in wandering. (5) The utilization rate of the home range was assessed according to the total length of the travelling course per grid square. Highly utilized areas in the home range were found along the Yokoyugawa valley without using areas far from the valley. (6) Diurnal activity was influenced by climate, although it was difficult to establish any clear daily rhythm. (7) The food items amounted to 39 species. (8) Distribution of densely utilized sites of food resources almost coincided with those of resting sites. (9) The reasons for the use of the complete home range by the B2 were also discussed.  相似文献   

14.
The activity budgets of individual orangutans were investigated at the Kutai Reserve, Indonesia. Activity profiles within and between individuals were compared to examine monthly variations in feeding patterns, potential energetic constraints imposed by large body size and parturition, and the costs of sociality. Animals showed monthly changes in travelling, feeding, and resting patterns. Monthly increases in travelling and feeding were associated with marked reductions in the time spent resting. Inter-individual variations in activity budgets did not exist among animals of the same age-sex class. Activity patterns differed, however, as a function of age and sex. Adult females and subadult males travelled and fed significantly longer than an adult male. Parturition had predictable effects on activity; one female reduced her feeding and travelling immediately following parturition. Adult male orangutan sociality appears to be limited by travel costs. Associations with females forced a male orangutan to travel significantly more compared with periods in which he was solitary. The male did not lose an appreciable amount of time feeding when accompanying a female.  相似文献   

15.
Feng J  Long Q  Khir AW 《Journal of biomechanics》2007,40(10):2130-2138
Earlier work of wave dissipation in flexible tubes and arteries has been carried out predominantly in the frequency domain and most of the studies used the measured pressure waveform for presenting the results. In this work we investigate the pattern of wave dissipation in the time domain using the separated forward and backward travelling waves in flexible tubes. We tested four sizes of latex tubes of 2m in length each, where a single semi-sinusoidal in shape, pressure wave, was produced at the inlet of each tube. Simultaneous measurements of pressure and flow waveforms were recorded every 5cm along the tubes and wave speed was determined using the pressure-velocity loop method (PU-loop). The measured data and wave speed were used to separate the pressure waveform and wave intensity, into their forward and backward directions, using wave intensity analysis (WIA). Also, the energy carried by the wave was calculated by integrating the relevant area under the wave intensity curve. The peak of the measured pressure waveform increased downstream, however, the peak of the separated forward pressure waveform decreased exponentially along the tube. Wave intensity and energy also dissipated exponentially along the travelling distance. The peaks of the separated pressure and wave intensity decreased in the forward in a similar exponential way to that in the backward direction in all four tube sizes. Also, the smaller the size of the tube the greater wave dissipation it caused. We conclude that wave separation is useful in studying wave dissipation in elastic tubes, and WIA provides a convenient method for determining the dissipation of the energy carried by the wave along the travelled distance. The separated pressure waveform, wave intensity and wave energy dissipate exponentially with the travelling distance, and wave dissipation varies conversely with the diameter of elastic tubes.  相似文献   

16.
The seasonal daily travel of a group of snub-nosed monkey (Pygathrix roxellana) was investigated using the group’s straight-line distance method. The group was followed from dawn to dusk for 30 consecutive days during each season to encompass all aspects of daily travel patterns. The results showed that in Summer and Autumn, the mean daily travel distance (m) was significantly longer than in Winter and Spring. There was no significant difference in the mean daily travel distance between Summer and Autumn or between Winter and Autumn. The mean travel distance (m/hr) during daytime was significantly higher in Summer and Autumn than in Spring, and in Autumn than in Winter. The travel of the group in all seasons had similar patterns. Traveling showed morning and afternoon peaks, with a rest period at the noon in a day. Seasonal food availability, length of daytime, and mean travel distance (m/hr) during daytime might have contributed to the different daily travel distances in different seasons.  相似文献   

17.
Mitigating traffic congestion on urban roads, with paramount importance in urban development and reduction of energy consumption and air pollution, depends on our ability to foresee road usage and traffic conditions pertaining to the collective behavior of drivers, raising a significant question: to what degree is road traffic predictable in urban areas? Here we rely on the precise records of daily vehicle mobility based on GPS positioning device installed in taxis to uncover the potential daily predictability of urban traffic patterns. Using the mapping from the degree of congestion on roads into a time series of symbols and measuring its entropy, we find a relatively high daily predictability of traffic conditions despite the absence of any priori knowledge of drivers'' origins and destinations and quite different travel patterns between weekdays and weekends. Moreover, we find a counterintuitive dependence of the predictability on travel speed: the road segment associated with intermediate average travel speed is most difficult to be predicted. We also explore the possibility of recovering the traffic condition of an inaccessible segment from its adjacent segments with respect to limited observability. The highly predictable traffic patterns in spite of the heterogeneity of drivers'' behaviors and the variability of their origins and destinations enables development of accurate predictive models for eventually devising practical strategies to mitigate urban road congestion.  相似文献   

18.
We explore here the evolution of skiing locomotion in the last few thousand years by investigating how humans adapted to move effectively in lands where a cover of snow, for several months every year, prevented them from travelling as on dry ground. Following historical research, we identified the sets of skis corresponding to the 'milestones' of skiing evolution in terms of ingenuity and technology, built replicas of them and measured the metabolic energy associated to their use in a climate-controlled ski tunnel.Six sets of skis were tested, covering a span from 542 AD to date. Our results show that: (i) the history of skiing is associated with a progressive decrease in the metabolic cost of transport, (ii) it is possible today to travel at twice the speed of ancient times using the same amount of metabolic power and (iii) the cost of transport is speed-independent for each ski model, as during running. By combining this finding with the relationship between time of exhaustion and the sustainable fraction of metabolic power, a prediction of the maximum skiing speed according to the distance travelled is provided for all past epochs, including two legendary historical journeys (1206 and 1520 AD) on snow. Our research shows that the performances in races originating from them (Birkebeiner and Vasaloppet) and those of other modern competitions (skating versus classical techniques) are well predicted by the evolution of skiing economy. Mechanical determinants of the measured progression in economy are also discussed in the paper.  相似文献   

19.
Stream-dwelling, juvenile Atlantic salmon, Salmo salar L., feed mainly on drifting invertebrates, usually by swimming upstream from a stationary position to intercept individual prey items. Laboratory experiments tested the prediction that individual salmon should reduce the distance over which they would travel (attack distance) to intercept drifting food items as the energy cost of swimming increases with increasing current velocity. Attack distance varied inversely with current velocity as expected. The fish's average speed of upstream movement relative to the substrate remained constant and the duration of individual attacks therefore declined as current velocity increased. Calculated reaction distances and a second ecperiment using tethered prey drifting at speeds independent of current velocity confirmed that these relationships were due to fish actually delaying attacks on perceived prey for longer periods as current velocity increased. Using estimated metabolic rates for burst swimming, it appears that energy expenditure per attack varies little with current velocity. Therefore, by reducing their reaction and attack distances in response to increasing current velocity, the fish reduced their energy cost of travel per attack.  相似文献   

20.
In February, 1972, a troop of 150 Japanese macaques was tranplanted from Kyoto, Japan, to Laredo, Texas, USA, after 20 years of study in Japan. As part of the general adaptation of the troop to its new environment, spacing behavior was observed in the central adult males [by independent rank, (1)Dai, (2)W, (3)Bus 62, and (4)Kojiwa 59]. Spot checks of locations, vertical space use, mobility patterns, and paths to and from a box of apples suggested that the major influences on spacing were rank, personality and history, social interactions, and several environmental factors (availability of vertical space, water, and shade, extreme heat, daily provisioning, etc).Dai exceeded the other males in use of vertical space, rate and distance of travel, and proximity to the apple box.W confined his high use of vertical space use primarily to one structure. His distance and rate of travel were low, and he maintained the greatest distance from the apple box.Bus 62 ranked second in use of vertical space, distance and rate of travel, and proximity to the apple box.Kojiwa 59 frequently changed sites in his use of vertical space. His distance and rate of travel were low, and he maintained long distances from the apple box.  相似文献   

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