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Empirical evidence from road safety literature suggests that vehicular speed is an important risk factor in the incidence and severity of road traffic crashes globally. Speed studies are at rudimentary stages in developing countries, thus making vehicular speed research imperative. The main aim of the study was to establish two major speed parameters, namely, the mean and dispersion, and their implications for more extensive and long-term speed monitoring in Ghana. Research workers stationed themselves in a parked car and used a radar gun to unobtrusively measure the travelling speeds of 28,489 vehicles at 15 different inter-urban locations on three highway categories. Excessive speeding is very pervasive on all highway categories in Ghana. Travelling speeds through settlements where a speed limit of 50 km/hour is mandatory were particularly excessive. Generally, 98%, 90% and 97% of vehicles exceeded the posted speed limit of 50 km/hour on national, inter-regional and regional roads respectively. Mean speeds and speed dispersions (as assessed by the standard deviations) through built-up areas were 81.3 +/- 17.3 km/hour on national roads, 64.7 +/- 12.3 km/hour on inter-regional roads and 72.6 +/- 13.4, km/hour on regional roads. On rural undivided highways with an 80 km/hour speed limit, mean and speed dispersions were 90 +/- 18.9 km/hour on national roads, 80.1 +/- 16 km/hour on inter-regional roads and 84.4 +/- 15.6 on regional roads; also translating into 66%, 47% and 60% of vehicles exceeding recommended speeds. In all cases, speed dispersions were notably higher than the value of 10 km/hour generally found in developed countries. Excessive speeding and wide speed dispersions are highly prevalent on Ghana's highways. These factors likely account for the high incidence of traffic crashes and fatalities in Ghana. An integrated speed monitoring and control programme and by-passing small and medium settlements would be required for the reduction of speed-related crashes, fatalities and injuries.  相似文献   
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Narrowing the gender technology gap in agricultural production has become a critical policy issue in sub‐Saharan Africa. A better understanding of the gender technology gap is essential for policy formulation and programme planning to ensure equity in resource allocation, and household‐level food security in low and middle income countries, such as Ghana. We employ a metafrontier approach to analyse the differences in the efficiency of male and female farmers, recognising the endogeneity of some of the variables in the inefficiency effects model, in particular the credit constraints of the rice farmers under study. Our findings show that while the rice farms themselves are very similar, average yields for male managed farms tend to be significantly higher than female managed farms reflecting higher seeding and fertiliser application rates on male managed farms. However, there is no significant difference between the genders in either land used for rice or total output per farm household. We find some evidence that relative to the metafrontier, male managed farms are less efficient than female managed farms. The results further show gender technology gap amongst the smallholder rice farmers with females’ technology gap ratio being significantly greater than that of males, with females operating on a production frontier closer to the metafrontier. Policies that provide females more access to productive resources and other agricultural services could assist in the generation of relatively higher output.  相似文献   
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The Capital Asset Pricing Model (CAPM), and the Fama-French and Carhart models have been widely applied in the developed and most emerging markets; however, there is scant evidence of the viability of the models on the African Frontier Stock Markets (AFSMs). This study examines the viability of the models for a sample that pools securities across nine AFSMs, and whether or not the risk factors of these models command risk premium on the AFSMs. The paper provides evidence of the existence of the size, value and momentum effects on the AFSMs. In addition, the models only partly capture the returns to size and book-to-market sorted portfolios on the AFSMs. Also, the risk factors of these models generally, command marginally significant premium on the AFSMs. Caution should in general be exercised when applying these models on the AFSMs.  相似文献   
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Agricultural research on climate change generally follows two themes: (i) impact and adaptation or (ii) mitigation and emissions. Despite both being simultaneously relevant to future agricultural systems, the two are usually studied separately. By contrast, this study jointly compares the potential impacts of climate change and the effects of mitigation policy on farming systems in the central region of Western Australia’s grainbelt, using the results of several biophysical models integrated into a whole‐farm bioeconomic model. In particular, we focus on the potential for interactions between climate impacts and mitigation activities. Results suggest that, in the study area, farm profitability is much more sensitive to changes in climate than to a mitigation policy involving a carbon price on agricultural emissions. Climate change reduces the profitability of agricultural production and, as a result, reduces the opportunity cost of reforesting land for carbon sequestration. Nonetheless, the financial attractiveness of reforestation does not necessarily improve because climate change also reduces tree growth and, therefore, the income from sequestration. Consequently, at least for the study area, climate change has the potential to reduce the amount of abatement obtainable from sequestration – a result potentially relevant to the debate about the desirability of sequestration as a mitigation option.  相似文献   
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Despite the significance of economic value indicators in the measurement of firm value, not much attention has been dedicated to how research and development (R&D) influences firms’ economic value. This study examines the relationship between R&D investments and firms’ economic value and considers the moderating role of age in the relationship using a dataset from manufacturing and information and technology firms in China. The results show that R&D investments impact firms’ economic value positively. This suggests that firms that invest in R&D are rewarded with a monopoly, which increases their market shares, thereby increasing economic value. Again, we find that older firms increase their economic value more than younger ones when they both invest in R&D. Thus, younger firms in China suffer from the liability of newness when they invest in R&D. It is recommended that these younger firms should strive to shorten the time to reap the returns from R&D investments.

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Adoption of cocoa production technologies has the potential to improve productivity and welfare of smallholder producers in low-income countries. While studies investigating synergies in agricultural technologies are growing, empirical evidence on the determinants and impacts of adopting multiple cocoa production technologies on smallholder farmers' welfare is scarce. Therefore, this study contributes by analyzing the determinants and effects of adoption of multiple cocoa production technologies on the welfare of smallholder farmers in Ghana. To achieve this, we used the multinomial endogenous switching regression and multivalued inverse probability regression adjustment models to a random sample of 2233 cocoa farmers from Ghana. The results show that various socioeconomic characteristics (e.g., farmer's age and experience), resource constraints (e.g., land ownership and credit access), market-related factors (e.g., distance to the market), and production shocks (e.g., rainfall) influence the adoption of multiple cocoa production technologies. Furthermore, the results reveal that adopting multiple production technologies significantly improves cocoa yields, gross income, per capita consumption expenditure, and reduces household food insecurity. Therefore, policies, such as financial support, need to be aimed at improving and strengthening smallholder cocoa producers' capacity to adopt synergistic conventional and non-conventional cocoa production technologies to maximize smallholder farmers' welfare.  相似文献   
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