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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Supply-demand balance in outward-directed networks and Kleiber's law | Theoretical Biology and Medical Modelling BioMed Central Research Open Access Supply-demand balance in outward-directed networks and Kleiber s law Page R Painter Address Office of Environmental Health Hazard Assessment California Environmental Protection Agency P.O. Box 4010 Sacramento CA 95812 USA Email Page R Painter - ppainter@oehha.ca.gov Corresponding author Published 10 November 2005 Received 03 May 2005 Accepted 10 November 2005 Theoretical Biology and Medical Modelling 2005 2 45 doi 10.1186 1742-4682-2-45 H This article is available from http www.tbiomed.com content 2 1 45 2005 Painter licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http creativecommons.org licenses by 2.0 which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Recent theories have attempted to derive the value of the exponent a in the allometric formula for scaling of basal metabolic rate from the properties of distribution network models for arteries and capillaries. It has recently been stated that a basic theorem relating the sum of nutrient currents to the specific nutrient uptake rate together with a relationship claimed to be required in order to match nutrient supply to nutrient demand in 3-dimensional outward-directed networks leads to Kleiber s law b 3 4 . Methods The validity of the supply-demand matching principle and the assumptions required to prove the basic theorem are assessed. The supply-demand principle is evaluated by examining the supply term and the demand term in outward-directed lattice models of nutrient and water distribution systems and by applying the principle to fractal-like models of mammalian arterial systems. Results Application of the supply-demand principle to bifurcating fractal-like networks that are outward-directed does not predict 3 4-power scaling and evaluation of water distribution
