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171.
Murayama H Moriyama N Mitobe H Mukai H Takase Y Shimizu Ki Kitayama Y 《Chemosphere》2003,52(5):825-833
A simple method for quantitative analyses of organic chlorine pesticides (OCPs) in environmental water samples such as rainwater, river water and seawater using activated carbon fiber filters (ACFF) is described. ACFF was used as adsorbent to collect the chemicals in water samples. The collection of OCPs was completed almost for one day by stirring the mixture of the sample and the ACFF chips at room temperature. The adsorbed OCPs on the ACFF could be extracted easily with toluene-ethanol (4:1) mixed solvent. The purified extract by a florisil column chromatograph was followed by the analysis using high-resolution gas chromatograph/high-resolution mass spectrometer. Recoveries of OCPs spiked to actual samples such as rainwater, river water and seawater samples were approximately more than 80%, and the coefficients of variations were within 10%. This method was applied to the actual samples and was confirmed to be applicable for monitoring sub-ng/l level OCPs in environmental water samples. 相似文献
172.
Elwood L. Shafer Robert Carline Richard W. Guldin H. Ken Cordell 《Environmental management》1993,17(5):669-682
The travel clost method (TCM) and contingent valuation method (CVM) were used to evaluate the economic value of six different
ecotourism activities involving observation of wildlife in Pennsylvania. The six activities were: catch-and-release trout
fishing; catch-and-release trout fishing with fly-fishing equipment; viewing waterfowl; watching elk; observing migration
flights of raptors; and seeing live wildlife in an environmental education setting. TCM results provided significant statistical
relationships between level of use and travel costs for the two types of trout fishing activities. CVM provided estimates
of consumer surplus for the other four sites. The consumers' surplus value (1988 dollars) of all six activities to participants
amounted to a total of more than $1.28 million annually—twice the total out-of-pocket expenditures of approximately $640,000
spent to visit the sites. The economic amenity values of the six activities compare favorably with similarly derived values
in other studies for hunting, fishing, hiking, and backpacking in dispersed recreation environments and wilderness areas in
western states. 相似文献
173.
The diversion of biodegradable waste from landfill is of key importance in developing a sustainable waste strategy for the next decade and beyond. The proliferation of waste treatment technologies such as Mechanical Biological Treatment, Anaerobic Digestion and Composting will be paramount in achieving this strategic goal. This paper evaluates the scientific information needed to undertake an effective assessment of the potential public health risks from exposure to bioaerosols in the vicinity of commercial composting activities. Knowledge gaps currently exist in the scientific and regulatory community that limit our ability to effectively characterise source-term emissions, develop reliable dose–response data and accurately model the dispersion of bioaerosols. Consequently reliable risk estimates cannot be developed to inform the management of these potential risks. This uncertainty may prove a barrier to progress in achieving waste diversion and composting targets in Wales and the rest of the UK. A robust and extensive evidence base is required to inform the risk assessment process. This paper advocates the need for further, more focussed research into hazard characterisation of viable and non-viable organisms, improved dose–response data, exposure assessment techniques and an evaluation of the existing risk control and mitigation measures currently adopted. It is hoped that his will enable effective, timely and proportional risk management and mitigation measures to be developed that will foster the confidence required in composting technologies to achieve waste diversion targets and develop sustainable waste strategies. 相似文献
174.
175.
Review of 10 mature septic system plumes in Ontario, revealed that phosphorus (P) attenuation commonly occurred close to the infiltration pipes, resulting in discrete narrow intervals enriched in P by a factor of 2-4 (. MSc thesis, Dept. Earth Sci., University of Waterloo, Waterloo, Ont.; Ground Water 36 (1995) 1000; J. Contam. Hydrol. 33 (1998) 405). Although these attenuation reactions appeared to be sustainable under present conditions, the potential for remobilization of this P mass, should geochemical conditions change, is unknown. To test the stability of these P solids, dynamic flow column tests were carried out using sediments from three of the previously studied sites (Cambridge, Langton and Muskoka) focusing on sediments from the 'High-P' and underlying (Below) zones. Tests were continued for 166-266 pore volumes (PVs), during which time varying degrees of water saturation were maintained. During saturated flow conditions, relatively high concentrations of PO4 were eluted from the Cambridge and Langton High-P zones (up to 4 and 9 mg/l P, respectively), accompanied by elevated concentrations of Fe (up to 1.4 mg/l) and Mn (up to 4 mg/l) and lower values of Eh (<150 mV). The Below zones from Cambridge and Langton, however, maintained lower concentrations of P (generally<2 mg/l), Fe (<0.2 mg/l) and Mn (<1 mg/l) and maintained higher Eh (>250 mV) during saturated flow conditions. During unsaturated flow, P and Fe declined dramatically in the High-P zones (P<1 mg/l, Fe<0.2 mg/l), whereas concentrations remained about the same during saturated and unsaturated flow in the Below zones. This behavior is at least partly attributed to the development of reducing conditions during saturated flow in the High-P zones, leading to reductive dissolution of Fe (III)-P solids present in the sediments. Reducing conditions did not develop in the Below zones apparently because of lower sediment organic carbon (OC) contents (0.03-0.04 wt.%) compared to the High-P zones (0.2-0.65 wt.%). At the Muskoka site, where the sediments were noncalcareous, low values of P (<0.2 mg/l) were maintained in both the High-P and Below columns and reducing conditions did not develop. Results indicate the possibility of remobilizing P accumulated below septic system infiltration beds should conditions become more reducing. This could occur if sewage loading patterns change, for example when a seasonal use, lakeshore cottage is converted to a permanent dwelling. 相似文献
176.
The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky
Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the
Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid
from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the
postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth.
Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form
seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes. 相似文献
177.
Kraaijeveld K Reumer BM Mouton L Kremer N Vavre F van Alphen JJ 《Die Naturwissenschaften》2011,98(3):175-180
Wolbachia is a maternally inherited bacterium that manipulates the reproduction of its host. Recent studies have shown that male-killing
strains can induce cytoplasmic incompatibility (CI) when introgressed into a resistant host. Phylogenetic studies suggest
that transitions between CI and other Wolbachia phenotypes have also occurred frequently, raising the possibility that latent CI may be widespread among Wolbachia. Here, we investigate whether a parthenogenesis-inducing Wolbachia strain can also induce CI. Parthenogenetic females of the parasitoid wasp Asobara japonica regularly produce a small number of males that may be either infected or not. Uninfected males were further obtained through
removal of the Wolbachia using antibiotics and from a naturally uninfected strain. Uninfected females that had mated with infected males produced
a slightly, but significantly more male-biased sex ratio than uninfected females that had mated with uninfected males. This
effect was strongest in females that mated with males that had a relatively high Wolbachia titer. Quantitative PCR indicated that infected males did not show higher ratios of nuclear versus mitochondrial DNA content.
Wolbachia therefore does not cause diploidization of cells in infected males. While these results are consistent with CI, other alternatives
such as production of abnormal sperm by infected males cannot be completely ruled out. Overall, the effect was very small
(9%), suggesting that if CI is involved it may have degenerated through the accumulation of mutations. 相似文献
178.
Matthew J. Eckelman Reid J. LifsetIoannis Yessios Ken Panko 《Journal of Cleaner Production》2011,19(11):1273-1278
Second Life is a virtual, open-access, and user-generated environment that has served as a platform for hosting everything from rock concerts to scientific conferences. Many institutions have also used Second Life as an educational tool, for example by, showcasing scientific exhibits or embedding video and images for learning purposes. Here we discuss the creation and use of an interactive, virtual industrial facility - the Elihu Paper Company - as a way to complement a traditional facility tours in a course in industrial environmental management. Virtual facilities offer a number of educational advantages over real-life ones: they are always open and available for tours, they can be accessed instantaneously from anywhere where there is an adequate internet connection, and most importantly, tours and embedded information can be tailored to specific educational objectives. Our experience in using Elihu Paper as a formal facility visit for the past several years shows that students had significantly more time than usual to ask questions, could and did explore the facility independently, and were still able to produce facility reports that fulfilled the educational objectives of the visits, including mapping material flows and explaining pollution prevention and sustainability opportunities. 相似文献
179.
In the course of their foraging bouts, bees frequently encounter spider webs among the vegetation. The ability to see and
avoid these webs is vital for the success of the individual bee’s foraging bout. In this study, we report on the response
of stingless bees (Trigona carbonaria) towards the webs of the St. Andrew’s Cross spider (Argiope keyserlingi). We studied the ability of bees to avoid webs in different contexts: when bees were on their foraging path or when they
were returning to the hive as well as when they were flying North or South. We show that the probability of a bee being able
to avoid a web depends on the context of the bee’s flight rather than the visual appearance of the web. Furthermore, the presence
of the spider seems to alert the bee to the web, resulting in bees being more able to avoid capture. We show, specifically,
that the probability of being captured is higher when the bee is returning to the hive compared with when the bee is foraging.
The likelihood of avoiding a web is also influenced by the compass direction of the flight, although to a lesser extent. Our
results indicate that the context of the predator–prey encounter has a significant influence on a bee’s ability to escape
interception by a spider web. 相似文献
180.
Recency preference of odour memory retrieval in honeybees 总被引:1,自引:0,他引:1
Free-flying honeybees (Apis mellifera) were trained on tasks in which they had to choose one of three odours for a reward of sugar water. In acquisition, the bees
learned this task in about five trials of training. Unrewarded retention tests showed that the odour memory was retained after
24-h delay. These findings are unsurprising. Integration experiments were then performed in which the bees had to learn two
successive tasks of odour discrimination with conflicting demands. In task 1 (20 trials), one of three odours provided sugar
water while the other two provided tap water. In task 2 (ten trials), which followed task 1 immediately, a different odour
provided the reward. The bees were given unrewarded tests immediately after training on task 2 and then tested again after
10 min, 22 h or 24 h. The 22-h delay coincided with the circadian time for the start of task 1 training, while the 24 h coincided
with the circadian time for the end of the task 2 training. Bees strongly preferred the rewarded odour for task 2 on immediate
testing and after a 10-min delay. After delays of 22 and 24 h, they still preferred the rewarded odour for task 2. We conclude
that the most recently acquired odour memory dominates behaviour in honeybees. The close association between floral odour
and reward availability under natural circumstances may predispose honeybees to rely more on the most recently rewarded odour
cue rather than on circadian time. 相似文献