منابع مشابه
Rural Roads
INTRODUCTION Rural Road connectivity is a key component of rural development, since it promotes access to economic and social services, thereby generating increased agricultural productivity, non-agriculture employment as well as non-agricultural productivity, which in turn expands rural growth opportunities and real income through which poverty can be reduced. A study (Fan et al. 1999) carried...
متن کاملO1: Roads Safety and Neurotrauma
Road traffic accidents account for approximately 3000 deaths on a daily basis, and 50 million injuries and 1.2 million deaths each year. In low-income and middle income countries, road traffic accidents account for 85% of deaths and 90% of annual disability. Casualties of this magnitude are a serious problem throughout the world and create a significant impact on society. In addition, neurologi...
متن کاملRoads and Innovation
We exploit historical data on planned highways, railroads, and exploration routes as sources of exogenous variation in order to estimate the effect of interstate highways on regional innovation: a 10% increase in a region’s stock of highways causes a 1.7% increase in regional patenting over a five-year period. In terms of the mechanism, we report evidence that roads facilitate local knowledge f...
متن کاملGrowing Urban Roads
We present a simple simulation of road growing dynamics that can generate global features as belt-ways and star patterns observed in urban transportation infrastructure. The road growing dynamics consist of two steps: Identifying the maximum transportation potential bewteen two locations within the city, followed by the generation of the least expensive road between these two locations. The sim...
متن کاملThe roads not taken
endangered, the highest level of threat. But one of the real problems facing the IUCN is a lack of data. More than half the 44 cetacean species are considered “data deficient”, meaning future research on population numbers is a priority. And the worry is that more data could show more species in trouble. The blue whale, fin whale and sei whale all remain listed as endangered until more evidence...
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ژورنال
عنوان ژورنال: Scientific American
سال: 1921
ISSN: 0036-8733
DOI: 10.1038/scientificamerican08271921-144