نتایج جستجو برای: and population density

تعداد نتایج: 16946265  

2011
Yuanzhi Shao Wenyong Hu Weirong Zhong Li Li

On the basis of two universal power-law scaling laws, i.e. the scaling dynamic hysteresis in physics and the allometric scaling metabolism in biosystem, we studied the dynamic response and the evolution of an immunosurveillant anti-tumor system subjected to a periodic external intervention, which is equivalent to the scheme of a radiotherapy or chemotherapy, within the framework of the growth d...

Journal: :Epidemiology and infection 2005
G T Innocent D J Mellor S A McEwen W J Reilly J Smallwood M E Locking D J Shaw P Michel D J Taylor W B Steele G J Gunn H E Ternent M E J Woolhouse S W J Reid

In Scotland, between 1995 and 2000 there were between 4 and 10 cases of illness per 100000 population per year identified as being caused by Escherichia coli O157, whereas in England and Wales there were between 1 and 2 cases per 100000 population per year. Within Scotland there is significant regional variation. A cluster of high rate areas was identified in the Northeast of Scotland and a clu...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Christopher T Fisher Helen P Pollard Isabel Israde-Alcántara Victor H Garduño-Monroy Subir K Banerjee

This paper presents 2,000 years of settlement and land use within the Lake Pátzcuaro Basin, Mexico. Three findings challenge the conclusions of previous research. We show (i) that initial land degradation was caused by settlement, not by agriculture; (ii) that population density inversely correlates with erosion; and (iii) that land degradation was associated with European Conquest but not from...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1998
J E Cohen C Small

The global distribution of the human population by elevation is quantified here. As of 1994, an estimated 1.88 x 10(9) people, or 33. 5% of the world's population, lived within 100 vertical meters of sea level, but only 15.6% of all inhabited land lies below 100 m elevation. The median person lived at an elevation of 194 m above sea level. Numbers of people decreased faster than exponentially w...

2011
N. Isern

We introduce the effect of cohabitation between generations to a previous model on the slowdown of the Neolithic transition in Europe. This effect consists on the fact that human beings do not leave their children alone when they migrate, but on the contrary they cohabit until their children reach adulthood. We also use archaeological data to estimate the variation of the Mesolithic population ...

Journal: :Urban affairs quarterly 1980
L M Verbrugge R B Taylor

The classical theory stating that high residential density produces negative social attitudes and undesirable behavior is questioned. Results of a survey undertaken in Baltimore, Maryland, are used to suggest that there are also positive effects of high density and large size and that the perceived effects vary by neighborhood.

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2009
Pu Wang Marta C González

We construct a two-dimensional geometric graph connecting individuals placed in space within a given contact distance. The individuals are distributed using a measured country's density of population. We observe that while large clusters (group of individuals connected) emerge within some regions, they are trapped in detached urban areas owing to the low population density of the regions border...

2017
Kathryn Willis Britta Denise Hardesty Lorne Kriwoken Chris Wilcox

Marine debris is a burgeoning global issue with economic, ecological and aesthetic impacts. While there are many studies now addressing this topic, the influence of urbanisation factors such as local population density, stormwater drains and roads on the distribution of coastal litter remains poorly understood. To address this knowledge gap, we carried out standardized surveys at 224 transect s...

2016
Guillaume Marche

San Francisco is known for its small acreage and high population density. Due to its attractiveness, the city has been subjected to a housing shortage, skyrocketing real-estate rates, and a steady process of gentrification over the past 20 years in particular. Access to public spaces and deliberation, negotiation, and conflicts over the proper uses and appearance of such spaces is one aspect of...

1994
Barnali Gupta Debashis Pal Robert Drago Jonathan Hamilton John Heywood William Holahan

Recent work suggests that Cournot oligopolists competing in a spatial model, with a uniform distribution of consumers, agglomerate in the center of the market. In this paper we analyze the robustness of this result with a general symmetric distribution of consumers and show that if the population density is "too thin" at the center of the market, then Cournot competition does not yield spatial ...

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