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61.
The theory of ecological cognition poses that the brains and behaviour of animals are shaped by the environmental challenges they face in their everyday lives. Site fidelity and homing ability was tested for five species of intertidal rock pool fish by tagging and displacing them to new rock pools at various distances from their ‘home’ rock pools. Three of the species were rock pool specialists whilst the remaining two spend a small proportion of their life in rock pools during early ontogeny. The three specialists showed strong site fidelity with >50 % of individuals found in the same pool 42 days after tagging. In contrast, the non-specialist species showed low fidelity and poor homing abilities. Homing success in the rock pool specialists remained relatively stable as displacement distance increased. The effect of body size on homing ability was species dependent, with only one species showing a significantly greater tendency to home with increasing size. 相似文献
62.
Visibility: science and regulation 总被引:9,自引:0,他引:9
63.
Keith M. White Jerome J. Congleton Olga J. Pendleton R. Dale Huchingson Rodger J. Koppa 《International journal of occupational safety and ergonomics》2013,19(4):315-335
This research used distal motor latency (DML) and vibration thresholds (VT) to evaluate 84 hand activity and wrist deviation combinations to determine the best association with carpal tunnel syndrome (CTS). Female volunteers, 2 healthy and 2 CTS diagnosed, were age matched and operated a keyboard for 4 hrs a day. Room temperature was 28°C(±2). Beginning DML and VT were taken with a relaxed neutral posture hand. The wrist was deviated in a randomly selected combination, and determinations were taken at 5-min intervals. The trial ended at 20 min or when discomfort was felt. The CTS conditions were discriminated by pain four times, DML once, and VT 14 times. Vibrometry was the most consistent CTS discriminator. The best VT results for wrist positions were obtained with wrist extension and extended extension, whereas the unclenched, clenched, and loaded power grip activities proved to be the most consistent hand activities. 相似文献
64.
Roads function as prime habitats and corridors for invasive plant species. Yet despite the diversity of road types, there
is little research on the influence of these types on the spread of invaders. Common ragweed (Ambrosia artemisiifolia), a plant producing large amounts of allergenic pollen, was selected as a species model for examining the impact of road
type on the spread of invasive plants. We examined this relationship in an agricultural region of Quebec, Canada. We mapped
plant distribution along different road types, and constructed a model of species presence. Common ragweed was found in almost
all sampling sites located along regional (97%) and local paved (81%) roads. However, verges of unpaved local roads were rarely
(13%) colonized by the plant. A model (53% of variance explained), constructed with only four variables (paved regional roads,
paved local roads, recently mown road verges, forest cover), correctly predicted (success rate: 89%) the spatial distribution
of common ragweed. Results support the hypothesis that attributes associated with paved roads strongly favour the spread of
an opportunistic invasive plant species. Specifically, larger verges and greater disturbance associated with higher traffic
volume create propitious conditions for common ragweed. To date, emphasis has been placed on controlling the plant in agricultural
fields, even though roadsides are probably a much larger seed source. Strategies for controlling the weed along roads have
only focused on major highways, even though the considerable populations along local roads also contribute to the production
of pollen. Management prioritizations developed to control common ragweed are thus questionable. 相似文献
65.
Paul Higginbotham Vince White Kevin Fogash Galip Guvelioglu 《International Journal of Greenhouse Gas Control》2011
This paper presents the results of a study to develop Air Products’ air separation unit (ASU) offerings for oxyfuel coal CO2 capture projects. A scalable “reference plant” concept is described to match particular sizes of power generation equipment, taking into account factors such as safety, reliability, operating flexibility, efficiency, and low capital cost. We describe the selection of a process cycle to exploit the low purity requirements, as well as the options for compression machinery and drivers as the scale of the plant increases and the sizes of referenced equipment limit the possibilities. We also explore integration with other elements of the system, such as preheating condensate or heating and expanding pressurised nitrogen. In addition, we consider how the ASU affects the flexibility of the oxyfuel system and discuss how its power consumption can be reduced during periods of high power demand. Finally, the advantages and disadvantages of different execution strategies for air separation unit projects are discussed, as well as alternative commercial models for the supply of oxygen. 相似文献
66.
67.
On estimating the exponent of power-law frequency distributions 总被引:5,自引:0,他引:5
Power-law frequency distributions characterize a wide array of natural phenomena. In ecology, biology, and many physical and social sciences, the exponents of these power laws are estimated to draw inference about the processes underlying the phenomenon, to test theoretical models, and to scale up from local observations to global patterns. Therefore, it is essential that these exponents be estimated accurately. Unfortunately, the binning-based methods traditionally used in ecology and other disciplines perform quite poorly. Here we discuss more sophisticated methods for fitting these exponents based on cumulative distribution functions and maximum likelihood estimation. We illustrate their superior performance at estimating known exponents and provide details on how and when ecologists should use them. Our results confirm that maximum likelihood estimation outperforms other methods in both accuracy and precision. Because of the use of biased statistical methods for estimating the exponent, the conclusions of several recently published papers should be revisited. 相似文献
68.
An important consideration in conservation and biodiversity planning is an appreciation of the condition or integrity of ecosystems. In this study, we have applied various machine learning methods to the problem of predicting the condition or quality of the remnant indigenous vegetation across an extensive area of south-eastern Australia—the state of Victoria. The field data were obtained using the ‘habitat hectares’ approach. This rapid assessment technique produces multiple scores that describe the condition of various attributes of the vegetation at a given site. Multiple sites were assessed and subsequently circumscribed with GIS and remote-sensed data. 相似文献
69.
James E. Bollinger Laura J. Steinberg Andrew J. Englande James P. Crews Janet M. Hughes Cruz Velasco Karen H. Watanabe William R. Hartley Christopher M. Swalm Jeffrey M. Mendler LuAnn E. White William J. George 《Journal of the American Water Resources Association》2000,36(6):1375-1390
ABSTRACT: Nutrient data from all available sources for the lower Mississippi River were examined for potential differences among sampling agencies and geographic locations for the period between 1960 and 1998. Monthly means grouped by parameter, sampling location and agency, were calculated and compared as paired sets, excluding those months where data were not available for both sets. Some significant differences were found between various agencies collecting nutrient data on the river, as well as between various stretches of river, especially in the case of phosphorus nutrient data. Results were used to synthesize data sets from which a history of nutrient loading in the Mississippi River was determined. General trends in nitrate+nitrite, total Kjeldahl nitrogen, orthophosphate, total phosphorus and silica loads, as well as changes in nutrient proportions and the specific limiting nutrient (by month) are reported. This study provides a useful summary of contemporary and historical nutrient data that may assist in the evaluation of Mississippi River water quality and its potential effect on the Gulf of Mexico. 相似文献
70.
Using Ion-Exchange Resins to Study Soil Response to Experimental Watershed Acidification 总被引:1,自引:0,他引:1
Szillery JE Fernandez IJ Norton SA Rustad LE White AS 《Environmental monitoring and assessment》2006,116(1-3):383-398
Ion-exchange resins (IER) offer alternative approaches to measuring ionic movement in soils that may have advantages over
traditional approaches in some settings, but more information is needed to understand how IER compare with traditional methods
of measurement in forested ecosystems. At the Bear Brook Watershed in Maine (BBWM), one of two paired, forested watersheds
is treated bi-monthly with S and N (28.8 and 25.2kgha−1yr−1 of S and N, respectively). Both IER and ceramic cup tension lysimeters were used to study soil solution responses after ∼11
years of treatment. Results from both methods showed treatments resulted in the mobilization of base cations and Al, and higher
SO4—S and inorganic N in the treated watershed. Both methods indicated similar differences in results associated with forest
type (hardwoods versus softwoods), a result of differences in litter quality and atmospheric aerosol interception capacity.
The correlation between lysimeter and IER data for individual analytes varied greatly. Significant correlations were evident
for Na (r=0.75), Al (r=0.65), Mn (r=0.61), Fe (r=0.57), Ca (r=0.49), K (r=0.41) and NO3—N (r=0.59). No correlation was evident between IER and soil solution data for NH4—N and Pb. Both IER and soil solution techniques suggested similar interpretations of biogeochemical behavior in the watershed. 相似文献