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71.
Ibáñez I Clark JS Dietze MC Feeley K Hersh M LaDeau S McBride A Welch NE Wolosin MS 《Ecology》2006,87(8):1896-1906
Efforts to anticipate threats to biodiversity take the form of species richness predictions (SRPs) based on simple correlations with current climate and habitat area. We review the major approaches that have been used for SRP, species-area curves and climate envelopes, and suggest that alternative research efforts may provide more understanding and guidance for management. Extinction prediction suffers from a number of limitations related to data and the novelty of future environments. We suggest additional attention to (1) identification of variables related to biodiversity that are diagnostic and potentially more predictable than extinction, (2) constraints on species dispersal and reproduction that will determine population persistence and range shifts, including limited sources or potential immigrants for many regions, and (3) changes in biotic interactions and phenology. We suggest combinations of observational and experimental approaches within a framework available for ingesting heterogeneous data sources. Together, these recommendations amount to a shift in emphasis from prediction of extinction numbers to identification of vulnerabilities and leading indicators of change, as well as suggestions for surveillance tools needed to evaluate important variables and the experiments likely to provide most insight. 相似文献
72.
73.
Norman S. Allen Robert McIntyre Julie Maltby Kerrod Claire Hill Michele Edge 《Journal of Polymers and the Environment》2018,26(11):4243-4257
Surface treated macro and nanoparticle TiO2 samples have been prepared, characterised and their efficiency as UV blockers evaluated in clear coatings and paints. The particle size of the ‘base’ TiO2 has been optimised to block UV radiation and the surface treatment developed to deactivate the photocatalytic activity of the surface of the TiO2 particles. The resultant UV blockers have been evaluated in both solvent and water-based clear coatings. Nanoparticle TiO2 has been prepared from ‘seed’ and the particle size was controlled by calcination. It was found that the choice of particle size is a compromise between UVA absorption, UVB absorption, visible transmission and photoactivity. It has been demonstrated that TiO2 with a crystallite size of 25 nm yields a product with the optimum properties. A range of dispersants was successfully used to disperse and mill the TiO2. Both organic and inorganic dispersants were used; 2-amino-2-methyl-1-propanol and 1-amino-2-propanol (MIPA) and P2O5 and Na2SiO3 respectively. The surface of the nano-TiO2 was coated with mixed oxides of silicon, aluminium, zirconium and phosphorous. Addition of the resultant coated nano-rutiles to an Isocyanate Acrylic clear coating prolonged the lifetime of that coating compared to the blank. Generally, a surface treatment based on SiO2, Al2O3 and P2O5 was more successful than one based on ZrO2, Al2O3 and P2O5. Higher addition levels of the surface treatment were beneficial for protecting the polymeric coating. The UV blocker products were also evaluated in a water-based acrylic, first a water-based dispersion of the UV blocker was prepared before addition to the acrylic. The dispersions and resultant acrylic thin films were evaluated using UV/Vis spectroscopy and durability assessed. The ratio of absorbance at 300:500 nm for the water-based dispersion was shown to be a good predictor of both the transparency of the resultant acrylic thin film and the durability of that film, in terms of weight loss. Macro grade titanium dioxide pigments were also prepared and coated with treatments of silica, alumina and siloxane and their photo-stabilising activity in alkyd paint film assessed and found to be directly related to the electron–hole pair mobility and trapping as determined by micro-wave spectroscopy. 相似文献
74.
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
75.
Despite proliferation of the use of air pollution models for regulatory application, major discrepancies still occur between models and also between models and observations, especially when oversimplistic models are used. The problem of predicting plume rise (and subsequently ground level concentrations) from a single source is evaluated here in terms of an integral plume rise and dispersion model (USPR) which encompasses both bouyant rise and turbulent spreading; thus avoiding the problems of the concatenation of separate plume rise and dispersion models. The wide range of validity of the USPR model is demonstrated is terms of plume rise by comparison with the highly buoyant GCOS and Kincaid plumes as well as with dense effluents. It is also shown to be in agreement with Briggs' two-thirds law when the restrictions applicable to the latter model are imposed. 相似文献
76.
77.
Graded recruitment in a ponerine ant 总被引:6,自引:0,他引:6
Michael D. Breed Jennifer H. Fewell Allen J. Moore Kristina R. Williams 《Behavioral ecology and sociobiology》1987,20(6):407-411
Summary (1) The giant tropical ant, Paraponera clavata, exhibits graded recruitment responses, depending on the type, quantity, and quality of a food source. More ants are initially recruited to a large prey or scavenge item than to a large quantity of sugar water. (2) Individual ants encountering prey items gauge the size and/or unwieldiness of the item, regardless of the weight, when determining whether to recruit. (3) The trail pheromone of this species is often used as an orientation device by individual ants, independent of recruitment of nestmates. (4) It is proposed that the foraging behavior of P. clavata represents one of the evolutionary transitions from the independent foraging activities of the primitive ants to the highly coordinated cooperative foraging activities of many higher ants. 相似文献
78.
R. Allen Brooks Martha S. Nizinski Steve W. Ross Kenneth J. Sulak 《Marine Biology》2007,152(2):307-314
The occurrence and relative abundance of tissue (arm) regeneration in the ophiuroid, Ophiacantha bidentata (Retzius), was examined in individuals collected primarily among colonies of the deep-water coral Lophelia pertusa off the southeastern United States. Seven deep-water coral sites (384–756 m), located between Cape Lookout, NC, and Cape
Canaveral, FL, were sampled in June 2004 using a manned submersible. The presence of regenerative tissue was evaluated by
visual inspection of each individual ophiuroid, and the proportion of regenerating arms per individual was examined relative
to size of individual, geographic location, and depth of collection. Ophiacantha bidentata, the dominant brittle star collected, commonly displayed signs of sublethal injury with over 60% of individuals displaying
some evidence of regeneration. These levels of regeneration rival those reported for shallow-water ophiuroids. Larger individuals
(>6.5 mm disc size) had a higher incidence of regeneration than smaller individuals. Size of individual and percent of regeneration
were negatively correlated with depth. Although O. bidentata was significantly less abundant in southern versus northern sites, ophiuroid abundance did not appear to be influenced by
amount or density of coral substratum. Presence of dense aggregations of O. bidentata indicates that they are an important component of the invertebrate assemblage associated with deep-water coral habitat especially
in the northern part of the study area. Assuming that observed frequencies of injury and subsequent regeneration represent
predation events then dense ophiuroid aggregations in deep-water coral habitats represent an important renewable trophic resource
within these communities. 相似文献
79.
Electric utility companies in the United States and Canada are participating in a unique environmental benchmarking program (EBP) designed to comparatively assess environmental performance. Each company annually provides data on emissionslwastes, compliance, and other environmental aspects to an independent consultant, Research Triangle Institute (RTI), whose staff compiles the data and computes approximately 80 discrete environmental performance metrics for each company. RTI provides a confidential report for each participant presenting the results of the assessment. In addition, RTI conducts a follow-up assessment to determine “best-practices” of each of the top performers for each metric. The EBP provides each participant with useful information on its strengths and weaknesses relative to the other companies in the program as well as ideas on how to improve its environmental performance. Annual participation in the program allows a company to measure improvement in performance on an annual basis. This article summarizes the evolution of the EBP and describes the study methods and reporting approach. Our goal in sharing this information is to demonstrate the usefulness of the program and encourage further participation by all major North American electric utilities. 相似文献
80.
Mahdi Ahmadi Josh Minot George Allen Lisa Rector 《Journal of the Air & Waste Management Association (1995)》2020,70(4):393-409
ABSTRACTA study was undertaken to identify patterns of consumer use of outdoor wood boilers or outdoor wood furnaces (technically referred to as outdoor wood-fired hydronic heaters (OWHHs)) and indoor wood stoves (IWSs) to inform the development of performance testing protocols that reflect real-life operating conditions. These devices are manually fed, and their usage protocols are a function of a number of variables, including user habits, household characteristics, and environmental factors. In this study, researchers logged the stack wall temperatures of 4 OWHH and 20 IWS units in the states of New York and Washington over two heating seasons. Stack wall temperature is an indicator of changes in combustion modes. Two algorithms were developed to identify usage modes and cold and warm start refueling events from the stack wall temperature time series. A linear correlation analysis was conducted to evaluate the effect of heat demand on usage patterns. The results and methods presented here will inform the cataloging of typical operational patterns of OWHHs and IWSs as a step in the development of performance testing procedures that represent actual in-home usage patterns.Implications: Current US regulatory programs for residential wood heating use a certification program to assess emissions and efficiency performance. Testing under this program uses a test that burns 100% of a single, standardized wood fuel charge to assess performance at different steady-state load conditions. This study assessed in-field operational patterns to determine if the current certification approach accurately characterized typical homeowner use patterns. The data from this study can be used to inform revisions to testing methods to increase certification test comparability between lab and field performance. 相似文献