97,362 research outputs found
Allometric Scaling of Countries
As huge complex systems consisting of geographic regions, natural resources,
people and economic entities, countries follow the allometric scaling law which
is ubiquitous in ecological, urban systems. We systematically investigated the
allometric scaling relationships between a large number of macroscopic
properties and geographic (area), demographic (population) and economic (GDP,
gross domestic production) sizes of countries respectively. We found that most
of the economic, trade, energy consumption, communication related properties
have significant super-linear (the exponent is larger than 1) or nearly linear
allometric scaling relations with GDP. Meanwhile, the geographic (arable area,
natural resources, etc.), demographic(labor force, military age population,
etc.) and transportation-related properties (road length, airports) have
significant and sub-linear (the exponent is smaller than 1) allometric scaling
relations with area. Several differences of power law relations with respect to
population between countries and cities were pointed out. Firstly, population
increases sub-linearly with area in countries. Secondly, GDP increases linearly
in countries but not super-linearly as in cities. Finally, electricity or oil
consumptions per capita increases with population faster than cities.Comment: 23 pages, 3 figure
On quark mass correction to the string potential
Following recent work by Lambiase and Nesterenko we study in detail the
interquark potential for a Nambu-Goto string with point masses attached to its
ends. We obtain exact solutions to the gap equations for the Lagrange
multipliers and metric components and determine the potential without
simplifying assumptions. We also discuss L\"{u}scher term and argue that it
remains universal.Comment: 15 pages LaTeX. 8 figures. Uses revtex.st
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