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排序方式: 共有476条查询结果,搜索用时 31 毫秒
461.
This study examined the relationships between four standardized measures of spatial ability—the Embedded Figures Test (EFT), the Mental Rotations Test (MRT), the Differential Aptitude Spatial Relations subtest (DAT), and the Building Memory Test (BMT)—and two measures of environmental knowledge. Three hundred and fifty-three college undergraduates were administered the EFT, MRT, DAT, BMT and two measures of environmental knowledge-a landmark location (LM) and route knowledge (RK) task. The two environmental knowledge tasks were based on a slide-simulated walk through an unfamiliar urban environment. A principal components analysis of the above six measures produced two factors; one consisting of the four spatial ability tests, and the other the two environmental knowledge tasks. The correlation between the two factors was 0·37, indicating that the spatial ability factor accounted for 13·69% of the variance in the environmental knowledge factor. 相似文献
462.
This article highlights recent research on the beneficial use of selected low frequency electromagnetic fields (EMF) as a
safe alternative therapy for treatment of cancer and other health problems. It is shown that EMF therapy provides a safe alternative
and adjunct modality for the treatment of cancer and other health problems, and therefore, research in this field deserves
more support. The paper also discusses some reports and hypothesis of potential risk of human exposure to low frequency EMF,
mainly to the power line frequency of 60 Hz. 相似文献
463.
Robert A. Zampella Nicholas A. Procopio Richard G. Lathrop Charles L. Dow 《Journal of the American Water Resources Association》2007,43(3):594-604
Abstract: We describe relationships between pH, specific conductance, calcium, magnesium, chloride, sulfate, nitrogen, and phosphorus and land‐use patterns in the Mullica River basin, a major New Jersey Pinelands watershed, and determine the thresholds at which significant changes in water quality occur. Nonpoint sources are the main contributors of pollutants to surface waters in the basin. Using multiple regression and water‐quality data for 25 stream sites, we determine the percentage of variation in the water‐quality data explained by urban land and upland agriculture and evaluate whether the proximity of these land uses influences water‐quality/land‐use relationships. We use a second, independently collected water‐quality dataset to validate the statistical models. The multiple‐regression results indicate that water‐quality degradation in the study area is associated with basin‐wide upland land uses, which are generally good predictors of water‐quality conditions, and that both urban land and upland agriculture must be included in models to more fully describe the relationship between watershed disturbance and water quality. Including the proximity of land uses did not improve the relationship between land use and water quality. Ten‐percent altered‐land cover in a basin represents the threshold at which a significant deviation from reference‐site water‐quality conditions occurs in the Mullica River basin. 相似文献
464.
Nicholas P. Lovrich John C. Pierce Taketsugu Tsurutani Takematsu Abe 《Journal of the American Water Resources Association》1986,22(2):229-236
ABSTRACT: This study examines the extent to which knowledge deficits pose a significant barrier to public support for nonpoint pollution management strategies. Such barriers would obtain if all of the following conditions are present: (1) many in the public lack knowledge relevant to those strategies; (2) variations in knowledge are linked only to relatively unchanging personal attributes; and (3) individuals with more knowledge are more likely to support the implementation of management strategies. Each of these conditions is subjected to empirical analysis in this study. The findings reported here derive from a survey of citizens in Spokane, Washington, the site of a major 208 Water Quality Management Program study. The results of the survey indicate that: portions of the public have enough knowledge to evaluate technically based management strategies; sources of public knowledge are sufficiently elastic that both policy area concern and policy relevant knowledge can be elevated in the short run; and both knowledge levels and general attitudes are related to the public's specific water policy preferences. The study concludes that the apparent lack of knowledge among the public is not necessarily a significant barrier to policy implementation, and that support for implementation may be generated through both knowledge enhancement and the tapping of existing political orientations through the placement of emphasis upon the seriousness of water resource problems. 相似文献
465.
Richard L. Shell Nicholas A. Damachi 《Journal of the American Water Resources Association》1985,21(2):323-330
To provide an overview of water utility information systems and the extent of computer use, a direct mail survey of all water utilities serving populations of 2,000 or more in the tri-state area - Ohio, Indiana, and Kentucky - was conducted. The following was determined: 1) utility profile information, e.g., public/private ownership, age, number of accounts, etc.; 2) an assessment of the degree of computerization presently in place to perform various functions; and 3) an assessment of any plans that the utilities may have for future computerization. To analyze the data, an index of computerization was defined as the number of departments or major activity areas of each utility that presently have some computerization. The relationship between the degree of computerization (measured by this index) and a utility's profile in terms of population served, annual revenue generated, and the number of customer accounts is discussed for each state in the survey. Discriminant analysis revealed strong significant differences between utilities that plan to use computers and those that do not. The differences were identified by the authors. Survey results revealed a rather limited use of computers in the tri-state area. Enormous potential exists in small and medium sized utilities for computerization to improve operational efficiency. 相似文献
466.
Melaleuca quinquenervia, is expanding rapidly throughout seasonally wet areas of southern Florida (USA), including the littoral zone of Lake Okeechobee.
Natural resource managers are concerned that a lower lake level regulation schedule under consideration for Lake Okeechobee,
while potentially beneficial to overall ecosystem health, might increase the rate of Melaleuca expansion. To investigate this possibility, Melaleuca saplings (harvested from the littoral zone) and 7-week-old seedlings (grown from harvested seeds) were subjected to various
hydroperiod treatments in replicated mesocosms. Hydroperiod treatments were selected based on a simulation of historical water
level variations. Saplings grew taller under longer hydroperiods with fluctuating water levels, including periods of submersion.
Time since germination affected the response of seedlings to inundation. Submersed 7-week-old seedlings grew slower and had
less biomass than submersed 12-week-old seedlings, yet mortality was low at both ages. Melaleuca's plasticity allows it to adapt to hypoxic, aquatic conditions by means of aquatic heterophylly and adventitious roots. Algae
and drought also increased mortality. Based on faster growth of Melaleuca under longer hydroperiods and its adaptability to seasonal flooding, a lower lake regulation schedule may not stimulate its
expansion. Therefore, water levels should not be manipulated only to control Melaleuca. Control of Melaleuca should continue using current practices such as manual removal or chemical treatment. 相似文献
467.
468.
Pesticides and trace elements in cannabis: Analytical and environmental challenges and opportunities
Caley B. Craven Nicholas Wawryk Ping Jiang Zhongshan Liu Xing-Fang Li 《环境科学学报(英文版)》2019,31(11):82-93
Cannabis is increasingly used for both medicinal and recreational purposes with an estimate of over 180 million users annually. Canada has recently legalized cannabis use in October 2018, joining several states in the United States of America (e.g., Colorado, California, and Oregon) and a few other countries. A variety of cannabis products including dry flowers, edibles, and oil products are widely consumed. With high demand for cannabis products worldwide, the quality of cannabis and its related products has become a major concern for consumer safety. Various guidelines have been set by different countries to ensure the quality, safety, and efficacy of cannabis products. In general, these guidelines require control of contaminants including pesticides, toxic elements, mycotoxins, and pathogens, as well as residual solvents in regard to cannabis oil. Accordingly, appropriate analytical methods are required to determine these contaminants in cannabis products for quality control. In this review, we focus on the current analytical challenges and method development for detection of pesticides and toxic elements in cannabis to meet various guidelines. 相似文献
469.
Nicholas S. Johnson 《Traffic injury prevention》2015,16(7):S103-S108
Objective: The goal of this study is to evaluate the crash performance of guardrail end terminals in real-world crashes. Guardrail end terminals are installed at the ends of guardrail systems to prevent the rail from spearing through the car in an end-on collision. Recently, there has been a great deal of controversy as to the safety of certain widely used end terminal designs, partly because there is surprisingly little real-world crash data for end terminals. Most existing studies of end terminal crashes used data from prior to the mid-1990s. Since then, there have been large improvements to vehicle crashworthiness and seat belt usage rates, as well as new roadside safety hardware compliant with National Cooperative Highway Research Program (NCHRP) Report 350, “Recommended Procedures for the Safety Performance Evaluation of Highway Features.” Additionally, most existing studies of injury in end terminal crashes do not account for factors such as the occurrence of rollover. This analysis uses more recent crash data that represent post-1990s vehicle fleet changes and account for a number of factors that may affect driver injury outcome and rollover occurrence.Methods: Passenger vehicle crashes coded as involving guardrail end terminals were identified in the set of police-reported crashes in Michigan in 2011 and 2012. End terminal performance was expected to be a function of end terminal system design. State crash databases generally do not identify specific end terminal systems. In this study, the coded crash location was used to obtain photographs of the crash site prior to the crash from Google Street View. These site photographs were manually inspected to identify the particular end terminal system involved in the crash. Multiple logistic regression was used to test for significant differences in the odds of driver injury and rollover between different terminal types while accounting for other factors.Results: A total of 1,001 end terminal crashes from the 2011–2012 Michigan State crash data were manually inspected to identify the terminal that had been struck. Four hundred fifty-one crashes were found to be suitable for analysis. Serious to fatal driver injury occurred in 3.8% of end terminal crashes, moderate to fatal driver injury occurred in 11.8%, and 72.3% involved property damage only. No significant difference in moderate to fatal driver injury odds was observed between NCHRP 350 compliant end terminals and noncompliant terminals. Car drivers showed odds of moderate to fatal injury 3.6 times greater than LTV drivers in end terminal crashes. Rollover occurrence was not significantly associated with end terminal type.Conclusions: Car drivers have greater potential for injury in end terminal crashes than light truck/van/sport utility vehicle drivers. End terminal designs compliant with NCHRP 350 did not appear to carry different odds of moderate driver injury than noncompliant end terminals. The findings account for driver seat belt use, rollover occurrence, terminal orientation (leading/trailing), control loss, and the number of impact events. Rollover and nonuse of seat belts carried much larger increases in injury potential than end terminal type. Rollover did not appear to be associated with NCHRP 350 compliance. 相似文献
470.
Trust in Sources of Soil and Water Quality Information: Implications for Environmental Outreach and Education
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Amber Saylor Mase Nicholas L. Babin Linda Stalker Prokopy Kenneth D. Genskow 《Journal of the American Water Resources Association》2015,51(6):1656-1666
Public trust in organizations focused on improving environmental quality is important for increasing awareness and changing behaviors that have water quality implications. Few studies have addressed trust in soil and water quality information sources, particularly for both agricultural and nonagricultural respondents of the same watersheds. Surveys in 19 watersheds across five states in the Midwest assessed trust in, and familiarity with, soil and water quality information sources. Overall, respondents most trusted University Extension, Soil and Water Conservation Districts, and the Natural Resource Conservation Service, while lawn care companies, environmental groups, and land trusts were less trusted. Significant differences in trusted sources were found between watersheds, and between agricultural and nonagricultural respondents across and within watersheds. Among agricultural respondents, a clear relationship exists between familiarity and trust; as familiarity with an organization increases, so too does level of trust. This relationship is less clear‐cut for nonagricultural respondents in this region. We highlight implications of these findings for soil and water quality outreach efforts. 相似文献