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排序方式: 共有283条查询结果,搜索用时 15 毫秒
21.
This paper probes the extent to which the public accurately perceives differences in transport risks. The paper is based on a survey of a random sample of the Norwegian population, conducted in September 2003. In the survey, respondents were asked: “How safe do you think it is to travel by means of (bus, train, etc.)?” Answers were given as: very safe, safe, a little unsafe, and very unsafe. A cursory examination of the answers suggested that the Norwegian public was quite well informed about differences in the risk of accident between different modes of transport, as well as between groups formed according to age and gender for each mode of transport. This paper probes the relationship between statistical estimates of risk and summary representations of perceived risk more systematically. It is found that the differences in fatality rate between different modes of transport are quite well perceived by the Norwegian public, irrespective of the way in which perceived risk is represented numerically. The relationship between statistical estimates of risk and numerical representations of perceived risk for each mode of transport is more sensitive to the choice of a numerical representation of perceived risk. A scale in which the answer “very safe” is assigned the value of 0.01 and the answer “very unsafe” is assigned the value of 10 is found to perform quite well. When the perception of risk is represented numerically according to this scale, a positive correlation between statistically estimated risk and perceived risk is found in seven of the eight comparisons that were made to determine how well variation in accident rates according to age and gender for car occupants, car drivers, cyclists and pedestrians are perceived. 相似文献
22.
Short Rick J.; Simeonsson Rune J.; Huntington Gail S. 《Canadian Metallurgical Quarterly》1990,21(2):88
We review components of Public Law (PL) 99-457 and discuss several concerns related to the practice of psychology and early intervention. PL 99-457 establishes a new national blueprint for expanding the opportunities and benefits of early intervention and preschool services to children and families. We examined implications of the new law in terms of the following broad categories: assessment and diagnosis, intervention, planning and case management, program evaluation, and interagency collaboration. On the basis of practice needs in these areas, we propose several areas of needed training for child practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
This paper reviews game-theoretic models that have been developed to explain road user behaviour in situations where road users interact with each other. The paper includes the following game-theoretic models:
- 1.
- A general model of the interaction between road users and their possible reaction to measures improving safety (behavioural adaptation). 相似文献
24.
In Situ X‐Ray Diffraction Studies on Structural Changes of a P2 Layered Material during Electrochemical Desodiation/Sodiation
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Young Hwa Jung Ane S. Christiansen Rune E. Johnsen Poul Norby Do Kyung Kim 《Advanced functional materials》2015,25(21):3227-3237
Sodium layered oxides with mixed transition metals have received significant attention as positive electrode candidates for sodium‐ion batteries because of their high reversible capacity. The phase transformations of layered compounds during electrochemical reactions are a pivotal feature for understanding the relationship between layered structures and electrochemical properties. A combination of in situ diffraction and ex situ X‐ray absorption spectroscopy reveals the phase transition mechanism for the ternary transition metal system (Fe–Mn–Co) with P2 stacking. In situ synchrotron X‐ray diffraction using a capillary‐based microbattery cell shows a structural change from P2 to O2 in P2–Na0.7Fe0.4Mn0.4Co0.2O2 at the voltage plateau above 4.1 V on desodiation. The P2 structure is restored upon subsequent sodiation. The lattice parameter c in the O2 structure decreases significantly, resulting in a volumetric contraction of the lattice toward a fully charged state. Observations on the redox behavior of each transition metal in P2–Na0.7Fe0.4Mn0.4Co0.2O2 using X‐ray absorption spectroscopy indicate that all transition metals are involved in the reduction/oxidation process. 相似文献
25.
McKinney MA Letcher RJ Aars J Born EW Branigan M Dietz R Evans TJ Gabrielsen GW Muir DC Peacock E Sonne C 《Environmental science & technology》2011,45(3):896-902
The relative contribution of regional contamination versus dietary differences to geographic variation in polar bear (Ursus maritimus) contaminant levels is unknown. Dietary variation between Alaska, Canada, East Greenland, and Svalbard subpopulations was assessed by muscle nitrogen and carbon stable isotope (δ(15)N, δ(13)C) and adipose fatty acid (FA) signatures relative to their main prey (ringed seals). Western and southern Hudson Bay signatures were characterized by depleted δ(15)N and δ(13)C, lower proportions of C(20) and C(22) monounsaturated FAs and higher proportions of C(18) and longer chain polyunsaturated FAs. East Greenland and Svalbard signatures were reversed relative to Hudson Bay. Alaskan and Canadian Arctic signatures were intermediate. Between-subpopulation dietary differences predominated over interannual, seasonal, sex, or age variation. Among various brominated and chlorinated contaminants, diet signatures significantly explained variation in adipose levels of polybrominated diphenyl ether (PBDE) flame retardants (14-15%) and legacy PCBs (18-21%). However, dietary influence was contaminant class-specific, since only low or nonsignificant proportions of variation in organochlorine pesticide (e.g., chlordane) levels were explained by diet. Hudson Bay diet signatures were associated with lower PCB and PBDE levels, whereas East Greenland and Svalbard signatures were associated with higher levels. Understanding diet/food web factors is important to accurately interpret contaminant trends, particularly in a changing Arctic. 相似文献
26.
Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and related compounds, have been identified as global pollutants and have shown their bioaccumulation into higher trophic levels in the food chain. PFCs have been found in remote areas far from sources, such as the Arctic. In this study spatial and temporal trends in the concentrations of selected PFCs were measured using archived liver samples of ringed seal (Phoca hispida) from East and West Greenland. The samples were collected in four different years at each location, between 1986 and 2003 in East Greenland and between 1982 and 2003 in West Greenland. PFOS was the major contributor to the burden of PFCs in samples, followed by perfluoroundecanoic acid (PFUnA). Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were also detected in most samples. Perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonamide (PFOSA) were only found sporadically. Perfluorooctanoic acid was not found in detectable concentrations in any sample. Regression analysis of logarithmic transformed PFOS, PFDA, and PFUnA median concentrations indicated a significant temporal trend with increasing concentrations at both locations. A spatial trend in PFOS concentrations (ANOVA, p < 0.0001) was observed between the two sampling locations, with significantly higher concentrations in seals from East Greenland. 相似文献
27.
The development of innovative relationships between psychologists and health care facilities is viewed as an example of "setting creation." These efforts involve predictable problems that are often not dealt with realistically due to a limited understanding of the setting-creation process. These arguments are applied to pediatric settings, where psychologists have recreated past problems by employing traditional helping approaches from their previous experience. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
29.
Björn-Ivar Klevebring Erik Bogren Rune Mahrs 《Metallurgical and Materials Transactions A》1975,6(2):319-327
A theory for determining the critical inclusion size with respect to void formation during hot working operation is presented. The theoretical model assumes that the relationship between inclusion size (r) and number (n) is of the typen = 1/rα. Equations are deduced for the three cases α = 2,α = 3 and α = 4. The most reliable results are obtained if α equals 3 or 4. The critical inclusion size is of the order of 2.5 to 3.5 μm for strains of about 0.7. 相似文献
30.