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1.
How much do road accidents cost the national economy?   总被引:1,自引:0,他引:1  
This paper presents estimates of how much road accidents cost the national economy, stated as a percentage of the gross national product (GNP). Official estimates of road accident costs from 1990 or later were compiled from easily accessible sources for twelve countries. Estimates of the gross national product were taken from OECD publications. On the average, the total costs of road accidents, including an economic valuation of lost quality of life, were estimated to about 2.5% of the gross national product. Excluding the valuation of lost quality of life, road accident costs on the average amounted to 1.3% of the gross national product. When valuation of lost quality of life is included, costs ranged from 0.5 to 5.7% of GNP. When valuation of lost quality of life is disregarded, costs ranged from 0.3 to 2.8% of GNP.  相似文献   

2.
Kinetic-theory, with the assumption of equipartition of granular energy, suggests that the pressure and viscosity of a granular mixture vary monotonically with the mass-ratio. Our simulation results show a non-monotonic behaviour that can be explained qualitatively by a simple model allowing for non-equipartition of granular energy between the species with different mass.  相似文献   

3.

Industrial/organizational (I/O) psychology, the subfield of psychology applied to the context of work, has been criticized for being dominated by U.S. authors because this dominance could prevent the generalizability of results and the enrichment of theories, paradigms, and approaches by researchers from other parts of the world. Previous estimates on the extent of the U.S. dominance are, however, likely restricted in scope, outdated, and likely biased by non-U.S. researchers who were socialized in the U.S. or received help by U.S. co-authors. As such, we measured the level of U.S. dominance by analyzing 5626 papers published from the top ten journals of the field of I/O psychology in the last eleven years and their authors. The results show that the U.S. dominance continues, although the internationalization of I/O psychology has steadily increased. An additional analysis of the gender distribution across our sample revealed that female first authorship is slightly more common among authors with no U.S. affiliation. We suggest several steps to further increase the level of internationalization.

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4.
The driving forces of diffusion reach their largest values in thin films. Temperature and voltage gradients may be steep simply because the film is thin.The matter and energy fluxes of diffusion contain, in principle, a whole series of cross terms. Commonly, we take only first order terms and ignore those of second and higher order; we restrict ourselves to “small” temperature and voltage gradients, to “the linear region of irreversible thermodynamics”.But how big is “small”? The present paper proposes that the linear region of irreversible thermodynamics extends from complete equilibrium to limits in which the energy change in the carrier system (e.g. phonons or plasmons), over a distance of one mean free path along the energy gradient, is comparable with the total energy in the carrier system. If the energy is E and the mean free path is λ, the limit occurs when
λ▽EE→1
Within this limit, experiments in thermomigration and electromigration measure equilibrium properties. The “reduced heat of transport” of a crystal defect is rigorously identified as the thermal energy of the defect structure.  相似文献   

5.
This is a non-trivial question when it comes to radiation dosimetry.The determination of absorbed dose or dose equivalent is oftenmore than an academic exercise or a research project. In themedical application of ionising radiation, the difference betweena dose delivered to a tumour being too low or too high can resultin either a recurrence or complications due to late effects.In this case, the dose has to be just right. And, the degreeof just-rightedness may require the combined standard uncertainty(with no coverage factor) to be just a few percent. If the radiationis being used to sterilise disposable medical products, a similarsituation can occur, although the required uncertainty may besomewhat larger. Too  相似文献   

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The growing prevalence of workplace drug testing and the narrow scope of previous reviews of the evidence base necessitate a comprehensive review of research concerning the efficacy of drug testing as a workplace strategy. A systematic qualitative review of relevant research published between January 1990 and January 2013 was undertaken. Inclusion criteria were studies that evaluated the effectiveness of drug testing in deterring employee drug use or reducing workplace accident or injury rates. Methodological adequacy was assessed using a published assessment tool specifically designed to assess the quality of intervention studies. A total of 23 studies were reviewed and assessed, six of which reported on the effectiveness of testing in reducing employee drug use and 17 which reported on occupational accident or injury rates. No studies involved randomised control trials. Only one study was assessed as demonstrating strong methodological rigour. That study found random alcohol testing reduced fatal accidents in the transport industry. The majority of studies reviewed contained methodological weaknesses including; inappropriate study design, limited sample representativeness, the use of ecological data to evaluate individual behaviour change and failure to adequately control for potentially confounding variables. This latter finding is consistent with previous reviews and indicates the evidence base for the effectiveness of testing in improving workplace safety is at best tenuous. Better dissemination of the current evidence in relation to workplace drug testing is required to support evidence-informed policy and practice. There is also a pressing need for more methodologically rigorous research to evaluate the efficacy and utility of drug testing.  相似文献   

9.
The fully penetrated state of anisotropic superconductors which are extended in thec-axis direction is analyzed using a model to describe the current distributions. Based on magnetooptical investigations on a rectangular single crystal and on a cubic melt-processed YBa2Cu3O7– sample, the current distributions found in (a, b)-planes and (a, c)-planes with the external magnetic field perpendicular to the plane are discussed. The easy flux penetration along the CuO2 layers is shown to have important consequences for the analysis of angledependent magnetization or torque measurements inc-axis direction extended samples.  相似文献   

10.
11.
This article provides a brief (non-exhaustive) review of some recent developments regarding the theoretical and possibly experimental study of 'exotic' quantum effects in the laboratory with special emphasis on cosmological particle creation, Hawking radiation and the Unruh effect.  相似文献   

12.
Whilst there has been a significant increase in the amount of consumer interest in the safety performance of privately owned vehicles, the role that it plays in consumers’ purchase decisions is poorly understood. The aims of the current study were to determine: how important vehicle safety is in the new vehicle purchase process; what importance consumers place on safety options/features relative to other convenience and comfort features, and how consumers conceptualise vehicle safety. In addition, the study aimed to investigate the key parameters associated with ranking ‘vehicle safety’ as the most important consideration in the new vehicle purchase. Participants recruited in Sweden and Spain completed a questionnaire about their new vehicle purchase. The findings from the questionnaire indicated that participants ranked safety-related factors (e.g., EuroNCAP (or other) safety ratings) as more important in the new vehicle purchase process than other vehicle factors (e.g., price, reliability etc.). Similarly, participants ranked safety-related features (e.g., advanced braking systems, front passenger airbags etc.) as more important than non-safety-related features (e.g., route navigation systems, air-conditioning etc.). Consistent with previous research, most participants equated vehicle safety with the presence of specific vehicle safety features or technologies rather than vehicle crash safety/test results or crashworthiness. The key parameters associated with ranking ‘vehicle safety’ as the most important consideration in the new vehicle purchase were: use of EuroNCAP, gender and education level, age, drivers’ concern about crash involvement, first vehicle purchase, annual driving distance, person for whom the vehicle was purchased, and traffic infringement history. The findings from this study are important for policy makers, manufacturers and other stakeholders to assist in setting priorities with regard to the promotion and publicity of vehicle safety features for particular consumer groups (such as younger consumers) in order to increase their knowledge regarding vehicle safety and to encourage them to place highest priority on safety in the new vehicle purchase process.  相似文献   

13.
Abstract and Key Results
•  This study revisits the “national cultural distance paradox” based on a sample of Japanese foreign direct investment (FDI) in 53 countries and regions over 30 years. Earlier studies on cultural distance assumed linear relationships and showed mixed results. We examine nonlinear relationships between cultural distance (CD) and entry mode and between CD and performance.
•  Results suggest that there is a nonlinear (inverted U-shape) relationship between CD and the choice of a joint venture as the preferred market entry mode, and between CD and performance.
•  We also found that the relationship between CD and performance is moderated by entry mode choice: the nonlinear relationship between CD and performance is stronger for joint ventures than for wholly owned subsidiaries.
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14.
15.
What is a reference?   总被引:1,自引:0,他引:1  
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16.
In this study, the relationship between matrix concentration and suppression of electrospray ionization (matrix effects) was investigated. Ion suppression of pesticides present in QuEChERS extracts was used as an example. Residue-free extracts of four different commodities, avocado, black tea, orange, and rocket (arugula), were fortified with 39 pesticides each. For many of the resulting 156 pesticide/matrix combinations, considerable matrix effects were observed if the coextracted matrix of 8 mg of equivalent sample (in the case of tea: 1.6 mg) was injected with the undiluted extracts. The reduction of these matrix effects was measured at 10 levels of dilution up to 1000-fold. The results obtained indicate a linear correlation between matrix effects and the logarithm of matrix concentration (or dilution factor) until the zero-effect level of further dilution was reached. Using the logarithmic equations, it could be shown that a dilution of extracts by a factor of 25-40 reduces ion suppression to less than 20% if the initial suppression is ≤80%. For stronger matrix effects or complete elimination of suppression, higher dilution factors were needed. The observed correlation was independent from the two instrument platforms used, but the degree of matrix effects differed slightly between the two mass spectrometers in this study.  相似文献   

17.
What is a proof?     
To those brought up in a logic-based tradition there seems to be a simple and clear definition of proof. But this is largely a twentieth century invention; many earlier proofs had a different nature. We will look particularly at the faulty proof of Euler's Theorem and Lakatos' rational reconstruction of the history of this proof. We will ask: how is it possible for the errors in a faulty proof to remain undetected for several years-even when counter-examples to it are known? How is it possible to have a proof about concepts that are only partially defined? And can we give a logic-based account of such phenomena? We introduce the concept of schematic proofs and argue that they offer a possible cognitive model for the human construction of proofs in mathematics. In particular, we show how they can account for persistent errors in proofs.  相似文献   

18.
The media continues to be a prominent and widely embraced channel for obtaining information on various topics, exerting considerable influence in shaping public opinions. This holds particularly true for the realm of automated vehicles (AVs), as the media consistently covers developments in this field, encompassing both positive aspects such as technological advancements, as well as negative occurrences like incidents involving self-driving cars colliding with pedestrians. The objective of this study was to utilize sentiment analysis techniques to evaluate the portrayal of AV technology in media news coverage. Data was retrieved from Sprinklr using keywords that are often associated with AVs. Over 1.7 million articles were collected on the keywords for relevant articles published between May 1, 2015 to May 24, 2021. Sentiment analysis was carried out on the cleaned data using three different models – VADER, TextBlob, and NRCLex. The sentiment analysis was separately conducted on the title and text of the articles. 2018 recorded the highest number of news articles on the AV technology. The number of negative sentiments in the title of articles published on the web in 2018 increased 12 times compared to the previous year. The negativity induced in 2018 in the news media did not continue in the next year, which explains that the technology experienced short term effects from the negative incidents associated with its early development. The news articles were also found to have subjectivity from the authors in the article text. The findings are expected to stimulate debates among industry players on how to bring the media along the journey of the development and eventual full deployment of AVs.  相似文献   

19.
20.
Muscovite mica is an important mineral that has become a standard substrate, due to its easy cleavage along the {001} planes, revealing a very flat surface that is compatible with many biological materials. Here we study mica surfaces by dynamic atomic force microscopy (AFM) operated in the non-contact mode (NC-AFM) under ultra-high vacuum (UHV) conditions. Surfaces produced by cleaving in UHV cannot be imaged with NC-AFM due to large surface charges; however, cleavage in air yields much less surface charge and allows for NC-AFM imaging. We present highly resolved NC-AFM images of air-cleaved mica surfaces revealing a rough morphology originating from a high density of nanometre-sized particles. Among these particles, we find regularly shaped structures indicating the growth of crystallites on the surface. The contamination layer cannot be removed by degassing in UHV; even prolonged heating at a temperature of 560?K under UHV conditions does not yield an atomically flat surface.  相似文献   

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