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101.
Schwab JJ Felton HD Rattigan OV Demerjian KL 《Journal of the Air & Waste Management Association (1995)》2006,56(4):372-383
Field evaluations and comparisons of continuous fine particulate matter (PM2,5) mass measurement technologies at an urban and a rural site in New York state are performed. The continuous measurement technologies include the filter dynamics measurement system (FDMS) tapered element oscillating microbalance (TEOM) monitor, the stand-alone TEOM monitor (without the FDMS), and the beta attenuation monitor (BAM). These continuous measurement methods are also compared with 24-hr integrated filters collected and analyzed under the Federal Reference Method (FRM) protocol. The measurement sites are New York City (the borough of Queens) and Addison, a rural area of southwestern New York state. New York City data comparisons between the FDMS TEOM, BAM, and FRM are examined for bias and seasonality during a 2-yr period. Data comparisons for the FDMS TEOM and FRM from the Addison location are examined for the same 2-yr period. The BAM and FDMS measurements at Queens are highly correlated with each other and the FRM. The BAM and FDMS are very similar to each other in magnitude, and both are approximately 25% higher than the FRM filter measurements at this site. The FDMS at Addison measures approximately 9% more mass than the FRM. Mass reconstructions using the speciation trends network filter data are examined to provide insight as to the contribution of volatile species of PM2.5 in the FDMS mass measurement and the fraction that is likely lost in the FRM mass measurement. The reconstructed mass at Queens is systematically lower than the FDMS by approximately 10%. 相似文献
102.
Objectives: The purpose of this investigation was to determine what older adults find most concerning about driving as they age and how these concerns are related to driving skill, behaviors, and experiences.Methods: In partnership with the Maryland Motor Vehicle Administration, a sample of 751 older adults ages 65 and older completed an online survey between October 2017 and May 2018. A content analysis was used to code open-ended responses about driver concerns, and multivariate logistic regression models were used to analyze the associations between driving concerns and driving skill, behavior, and experiences.Results: Eighty-four percent of participants reported at least one driving concern, with 44% concerned about others’ driving, 34% concerned about their own driving, and 24% concerned about driving conditions. The most frequently mentioned driving concerns were other drivers in general, driving at night, visual ability and awareness, and other drivers being aggressive or reckless. Being concerned with their own driving was significantly associated with decreased perceived driving skill and increased odds of experiencing negative driving experiences in the past year. Being concerned about others’ driving was associated with increased odds of wearing a seat belt (adjusted odds ratio [AOR]?=?2.67; 95% confidence interval [CI], 1.02, 7.00), having high perceived driving skills in emergency situations (AOR = 1.56; 95% CI, 1.14, 2.12), and getting in a near crash or collision in the past year (AOR = 1.50; 95% CI, 1.04, 2.18).Conclusions: Older adult drivers are frequently concerned about their own driving as well as the driving of others. Implications for future research and health practice are discussed. 相似文献
103.
Nest Predation and Population Declines in Illinois Songbirds: a Case for Mesopredator Effects 总被引:2,自引:0,他引:2
Kenneth A. Schmidt 《Conservation biology》2003,17(4):1141-1150
104.
Summary In 1981–1985, we studied territory dynamics in a southeastern Idaho sage sparrow population to evaluate the hypothesis that territory shifts represent adaptive adjustments in site use. We predicted that shifts should (1) result in changes in territory characteristics, (2) be influenced by previous reproductive success and result in greater success, and (3) decline in magnitude for individual males over time. Habitat features of territories changed little as a result of shifts, but territory size increased. Correspondingly, habitat features of territories were unrelated to reproductive success, whereas territory size was positively related. The magnitude of territory shifts was negatively correlated with preshift fledging success, and after shifts, males experienced greater average reproductive success than before. Successive territory shifts by individual males became progressively smaller. Thus, territory shifting by sage sparrows seems to be adaptive behavior aimed primarily at increasing territory size. 相似文献
105.
Seven colonies of Lobophytum compactum Tixier-Durivault, 1956, which produce isolobophytolide as the major secondary metabolite, were selected from a fringing reef in the Pelorus Channel, Palm Island Group (18°34S; 146°29E), North Queensland, Australia. In September 1991, they were sectioned to afford two portions which were relocated to a grid, and a significant part of the parent colony which was left in place. The aim of the experiment was to determine the effect of relocation and contact with a toxic alga on the secondary metabolite content of a soft coral. A significant increase in the concentration of isolobophytolide was observed for all relocated colonies (n=14, p=0.001) compared to the non-relocated control colonies. This decreased after 2 mo, and was not significantly different from that of the non-relocated control colonies (n=14, p=0.881). After 1 mo, Plocamium hamatum J. Agardh plants were placed in direct contact with 50% of the relocated colonies. All soft-coral colonies in contact with the alga (n=7), showed tissue necrosis on the parts in direct contact with the alga after a further 2 wk. Tissues of the relocated control colonies (n=7), and those portions of treated colonies which were not in direct contact with the alga, were not affected. The parts of the colonies in contact with the alga showed a significant decrease in lipid content over time (n=7, p=0.001) and also a decrease in the concentration of the diterpene isolobophytolide (n=7, p=0.001). The effects of P. hamatum on the soft coral were essentially restricted to contract necrosis; chemical variations in the affected tissue were the outcomes of this necrosis. These results indicate that stress due to relocation is a more important factor in the variation of isolobophytolide levels in the soft coral L. compactum than is contact with the alga P. hamatum. 相似文献
106.
107.
Patricia M. Erickson Kenneth J. Ladwig Robert L. P. Kleinmann 《Environmental geochemistry and health》1985,7(1):16-25
The most widely used technique for abatement of acid drainage from inactive surface mines and refuse disposal areas is revegetation of a soil cover applied to the waste material. Nonetheless, acid production often persists and in some cases, limits establishment of vegetation. This paper reports on several field studies intended to determine the location of pyrite oxidation zones and migration pathways of oxidation products at inactive spoil and refuse sites. Oxygen required for pyrite oxidation is believed to he provided in the gaseous state from the atmosphere. Therefore, the oxygen concentration in unsaturated mine waste should provide an estimate of the weathering tendency in the local environment. We are currently monitoring gas composition in refuse and spoil at six sites. Barren refuse appeared to be oxygenated (>2% 02) in a shallow zone extending less than 1 metre below the surface during most of the year. Preliminary data from coal spoil showed that oxygen can be available throughout the unsaturated thickness, even at a revegetated site. Gas composition varied vertically and laterally at a single site and also appeared to show seasonal dependence. Hydrologic factors are also important in acid production and transport. Discharge monitoring alone does not adequately describe the mass transport of acid products through the spoil. For example, at one reclaimed mine the mean sulfate content in six monitoring wells ranged from 24% to 240% of the mean concentration at the discharge point. Sources of recharge and relative flow rates determine the contribution of a particular zone to overall discharge quality. These basic studies of acid production and transport indicate some shortcomings of standard reclamation practices at certain sites. This information will he used to develop alternative abatement technology designed to mitigate acid production at the source. 相似文献
108.
The effect of salinity on survival, bioenergetics and predation risk was studied in two common mud crabs in the Gulf of Mexico,
Eurypanopeus depressus and Panopeus simpsoni. Eurypanopeus survived better at low salinities (the 28-day LC50 of E. depressus was 0.19 PSU compared with 6.97 PSU for P. simpsoni). While low salinity increased energy expenditure and reduced food consumption and absorption, resulting in lower scope for
growth, identical responses to salinity occurred in both species. Both species also had similar salinity-dependent patterns
of hyper-osmoregulation. Because these physiological mechanisms could not explain differences between the two species in salinity
tolerance, we explored the effect of salinity on competition for refugia. Eurypanopeus had higher resource holding potential for refugia, especially at low salinity. As a consequence it had lower predation risk
to blue crabs in laboratory experiments. The higher tolerance by E. depressus for low salinities, and greater resource holding potential for refugia may explain why it has a more euryhaline distribution
than P. simpsoni. 相似文献
109.
Kenneth R. Young 《Conservation biology》1994,8(4):972-976
Roads are often a causal agent in the degradation of tropical forests; in this paper their impact is discussed for the forested, humid montane zone. Because of their steep slopes and high elevations, these forests have disturbance regimes associated with slope instability, limited resilience, and numerous species that are elevational specialists, restricted to narrow altitudinal belts. Roads often augment slope instability and fragment ranges of specialized species. Roads can allow uncontrolled extraction of natural products and landscape conversion. Improvements are needed in the design, construction, and maintenance of these roads. Also needed are studies and mitigation efforts to reduce their effects on the specialized biota of montane forests. 相似文献
110.
Kenneth L. Wertz 《Journal of Environmental Economics and Management》1977,4(4):335-343
Pollution taxes have been studied as instruments for promoting environmental objectives in an efficient manner. Their adoption has also been recommended, although less rigorously, on equity grounds. In the case of solid wastes it has been contended that persons whose waste generation occasions local public outlays for refuse service should pay commensurately, but that they often do not under general revenue financing. How proposals for federal product charges might reduce current inequities, so conceived, is the subject of the paper. The behavioral responses of local public officials to federal grants funded by charge revenues and the design of the grant formula are identified as potentially important factors in that regard. 相似文献