Environmental Modeling & Assessment - Determining whether there is a causal link between chronic exposure to PM2.5 (atmospheric particulate matter with a diameter of 2.5 µm or... 相似文献
Many prey species have a genetic predisposition to recognise and respond to predators and can fine-tune their anti-predator behaviour following appropriate experience. Although the Trinidadian guppy ( Poecilia reticulata) has become a model species for the investigation of adaptive behaviour, the extent to which experience mediates predator recognition remains unclear. In this study, we examined the effects of relaxed predation pressure on patterns of anti-predator behaviour in populations differing in evolutionary history. The anti-predator behaviour of wild- and laboratory-born guppies from high- and low-predation localities in Trinidad were compared using three models resembling Crenicichla alta, a dangerous guppy predator, Aequidens pulcher, a less dangerous piscivore, and a snake. Snakes are not known to prey on guppies in Trinidad. Specifically, the following predictions were tested: (1) wild caught fish from the high-predation localities (where guppies co-occur with C. alta and A. pulcher) would respond to the three models according to their perceived level of threat, whereas guppies from the low-predation site would show a reduced response to all of the predator models; (2) high-predation laboratory-reared fish would display a reduced but qualitatively similar response to their wild counterparts; and (3) there would be no behavioural differences between wild- and laboratory-reared low-predation fish. In accordance with these predictions, the results revealed that wild fish originating from high-predation sites responded more strongly to the models than fish from low-predation sites. When reared in the laboratory, guppies from the high-predation population showed a reduced response compared to their wild-caught counterparts, but there was no difference in the behaviour of wild- and laboratory-reared low-predation fish. Model type affected predator inspection behaviour but not schooling tendency, and both wild- and laboratory-reared guppies were more wary of the fish models than the snake. These results suggest that early experience differentially mediates the anti-predator responses of fish from high-risk localities. 相似文献
ABSTRACT The Santa Cruz lowlands, east Bolivia, are one of South America’s most dynamic agricultural frontiers. In the Chiquitania, bordering Brazil, San Ignacio de Velasco was in 2017 ranked first nationally in terms of deforestation. There, two deforestation fronts meet with mechanized agriculture expanding from the West and South and cattle ranching from the East. Chiquitano communities are demographically dominant locally but often face land scarcity. Because of their comparatively low impact on forest vegetation, they are not well represented in broad-scale quantitative Land Use/Land Cover (LULC) studies. Based on an empirical, human geographical approach, this paper investigates the transformation of the local indigenous productive matrix, the associated land-use patterns and potential socio-ecological implications. The overall aim is to bear witness to the rapid and profound reconfiguration of traditional livelihoods with their integration in the market economy and to highlight the significance of micro-scale LULC-processes at global scale. 相似文献
Goal, Scope and Background Atmospheric sampling (gas and particles) of 5 phenols (phenol, m-cresol, p-cresol, o-cresol, pentachlorophenol) and 15 nitrophenols
(3-methyl-2-nitrophenol, 3-nitrophenol, 4-methyl-2-nitrophenol, 5-methyl-2-nitrophenol, 2-methyl-3nitrophenol, 3-methyl-4-nitrophenol,
2,6-dinitrophenol, bromoxynil, 2,5-dinitrophenol, 2,6-dinitro-p-cresol, 2,4-dinitrophenol, ioxynil, DNOC, 3,4-dinitrophenol,
dinoseb) on XAD-2 resin (20 gr) and glass fibre filters, respectively, were performed in 2002 by using 'Digitel DA80' high
volume samplers. These measurements were undertaken in order to show spatial and geographical variations of concentrations
and the role of traffic in the emissions of these compounds to the atmosphere.
Methods Sampling were performed in Strasbourg (eastern France), in its vicinity (Schiltigheim) and in Erstein. Sites were chosen
to be representative of urban (Strasbourg), suburban (Schiltigheim) and rural (Erstein) conditions. Field campaigns were undertaken
simultaneously in urban and suburban sites during all the seasons during 4 hours at a flow rate of 60 m3.h-1, which gives
a total of 240 m3 of air per sample. Period of sampling varied between 06h00 to 10h00, 11h00 to 15h00 and 18h00 to 22h00 in
order to evaluate a variation of concentration during automobile traffic between urban, suburban and rural areas. Gas and
particle samples were separately Soxhlet extracted for 12 h with a mixture of CH2Cl2 / n-hexane (50:50 v/v), concentrated
to about 1 mL with a rotary evaporated and finally dried under nitrogen. Dry extracts were dissolved in 1 mL of CH3CN. Before
analysis, extracts were sylilated by using MTBSTFA. Analysis was performed by GC/MSD in the SIM mode.
Results and Discussion Partitioning of phenolic compounds between gas and particle phases seems to be mainly correlated with vapour pressure. Among
phenolic compounds analysed, phenol, p-cresol, pentachlorophenol and 2.4-dinitrophenol were detected in all samples and emissions
from traffic seems to be the major source for the presence of these compounds to the atmosphere. No increase of concentrations
in autumn tend to confirm this hypothesis since, with the use of domestic heating in colder months, increases of PAHs concentrations
were observed and these compounds are known to be emitted by all combustion processes.
Pentachlorophenol is a special case since this molecule is only used as wood preservative. Its presence in all atmospheric
samples, whatever the locations and the period of time is the consequence of its persistence.
Conclusions and Perspectives These measurements demonstrate that phenols and nitrophenols are emitted to the atmosphere and further measurements, in order
to confirm their sources, their behaviour and their potential impact to the air quality and to human health should be undertaken
especially since the literature collected is relatively old. Concentrations of pentachlorophenol measured are very low and,
due to its toxicity, further investigations should be undertaken.
- * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on 'Chemistry and Environment', 29 August
to 1 September 2004, Bordeaux, France. 相似文献
Potassium silicate drilling fluids(PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥ 40 m3/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments.Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils. 相似文献
The social structure of animal aggregations may vary considerably in both space and time, yet little is known about how this
affects vigilance. Here, we investigate the vigilance architecture of a colony of wild-living grey-headed flying-foxes (Pteropus poliocephalus) in Australia and examine how spatial as well as temporal variation in social organization influences social and environmental
vigilance. We sampled color-marked individuals at different stages of the reproductive cycle and the year and at different
locations in the colony to examine the effects of temporal and spatial factors on social and environmental vigilance. We found
that vigilance architecture reflected the social structure of the colony, with the highest environmental vigilance being displayed
by bats at the periphery of the colony, and the highest social vigilance by bats that roosted at intermediate distances from
the colony’s edge. Furthermore, we found that vigilance levels reflected changes in reproductive state, with social vigilance
increasing toward the mating season, particularly in males. Our findings show that spatial and temporal variation in social
structure can have differential effects on social and environmental vigilance. This highlights the necessity to differentiate
between functions of vigilance to understand fully vigilance architecture in aggregations of social animals. 相似文献
Objective: Considerable evidence indicates that medical conditions prevalent among older individuals lead to impairments in visual, cognitive, or psychomotor functions needed to drive safely. The purpose of this study was to explore the factors determining driving difficulties as seen from the viewpoint of 30 older drivers with mild cognitive impairment (MCI) and 30 age-matched controls without cognitive impairment.
Methods: Perceptions of driving difficulties from both groups were examined using data from an extensive questionnaire. Samples of drivers diagnosed with MCI and age-matched controls were asked to report the frequency with which they experienced driving difficulties due to functional deficits and knowledge of new traffic rules and traffic signs.
Results: The analysis revealed that 2 factors underlie MCI perceptions of driving difficulties, representing (1) difficulties associated with late detection combined with slowed response to relevant targets in the peripheral field of view and (2) difficulties associated with divided attention between tasks requiring switching from automatic to conscious processing particularly of long duration. The analysis for healthy controls revealed 3 factors representing (1) difficulties in estimating speed and distance of approaching vehicles in complex (attention-dividing) high-information-load conditions; (2) difficulties in moving head, neck, and feet; and (3) difficulties in switching from automatic responses to needing to use cognitive processing in new or unexpected situations.
Conclusions: Though both group analyses show difficulties with switching from automatic to decision making, the difficulties are different. For the control group, the difficulty in switching involves switching in new or unexpected situations associated with high-information-load conditions, whereas this switching difficulty for the MCI group is associated with divided attention between easier tasks requiring switching. These findings underline the ability of older drivers (with MCI and without cognitive impairment) to indicate probable impairments in various driving skills. The patterns of difficulties perceived by the MCI group and the age-matched healthy control group are indicative of demanding driving situations that may merit special attention for road designers and road safety engineers. They may also be considered in the design of older drivers’ fitness to drive evaluations, training programs, and/or vehicle technologies that provide for older driver assistance. 相似文献