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Malthusian Growth Model
A Malthusian growth model, sometimes called a simple exponential growth model, is essentially exponential growth based on the idea of the function being proportional to the speed to which the function grows. The model is named after Thomas Robert Malthus, who wrote ''An Essay on the Principle of Population'' (1798), one of the earliest and most influential books on population."Malthus, An Essay on the Principle of Population: Library of Economics" Malthusian models have the following form: : P(t) = P_0e^ where * ''P''0 = ''P''(0) is the initial population size, * ''r'' = the population growth rate, which Ronald Fisher called the Malthusian parameter of population growth in '' The Genetical Theory of Natural Selection'', and Alfred J. Lotka called the ''intrinsic rate of increase'', * ''t'' = time. The model can also be written in the form of a differential equation: : \frac = rP with initial condition: ''P''(0)= ''P''0 This model is often referred to as the exponential law ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exponential Growth
Exponential growth occurs when a quantity grows as an exponential function of time. The quantity grows at a rate directly proportional to its present size. For example, when it is 3 times as big as it is now, it will be growing 3 times as fast as it is now. In more technical language, its instantaneous rate of change (that is, the derivative) of a quantity with respect to an independent variable is proportional to the quantity itself. Often the independent variable is time. Described as a function, a quantity undergoing exponential growth is an exponential function of time, that is, the variable representing time is the exponent (in contrast to other types of growth, such as quadratic growth). Exponential growth is the inverse of logarithmic growth. Not all cases of growth at an always increasing rate are instances of exponential growth. For example the function f(x) = x^3 grows at an ever increasing rate, but is much slower than growing exponentially. For example, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Allen Bartlett
Albert Allen Bartlett (March 21, 1923 – September 7, 2013) was an American professor of physics at the University of Colorado at Boulder. As of July 2001, Professor Bartlett had lectured over 1,742 times since September 1969 on ''Arithmetic, Population, and Energy''. Bartlett regarded the word combination "sustainable growth" as an oxymoron, and argued that modest annual percentage population increases could lead to exponential growth. He therefore regarded human overpopulation as "The Greatest Challenge" facing humanity. Career Bartlett received a B.A. in physics at Colgate University (1944), and an M.A. (1948) and Ph.D. (1951) in physics at Harvard University. Bartlett joined the faculty at the University of Colorado at Boulder in September 1950. In 1978 he was national president of the American Association of Physics Teachers. He was a fellow of the American Physical Society and of the American Association for the Advancement of Science. In 1969 and 1970 he served two terms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and plants, and has specific uses within such fields as ecology and genetics. Etymology The word ''population'' is derived from the Late Latin ''populatio'' (a people, a multitude), which itself is derived from the Latin word ''populus'' (a people). Use of the term Social sciences In sociology and population geography, population refers to a group of human beings with some predefined feature in common, such as location, Race (human categorization), race, ethnicity, nationality, or religion. Ecology In ecology, a population is a group of organisms of the same species which inhabit the same geographical area and are capable of Sexual reproduction, interbreeding. The area of a sexual population is the area where interbreeding is possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematical Modeling
A mathematical model is an abstract and concrete, abstract description of a concrete system using mathematics, mathematical concepts and language of mathematics, language. The process of developing a mathematical model is termed ''mathematical modeling''. Mathematical models are used in applied mathematics and in the natural sciences (such as physics, biology, earth science, chemistry) and engineering disciplines (such as computer science, electrical engineering), as well as in non-physical systems such as the social sciences (such as economics, psychology, sociology, political science). It can also be taught as a subject in its own right. The use of mathematical models to solve problems in business or military operations is a large part of the field of operations research. Mathematical models are also used in music, linguistics, and philosophy (for example, intensively in analytic philosophy). A model may help to explain a system and to study the effects of different components, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empirical Laws
Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term ''law'' has diverse usage in many cases (approximate, accurate, broad, or narrow) across all fields of natural science (physics, chemistry, astronomy, geoscience, biology). Laws are developed from data and can be further developed through mathematics; in all cases they are directly or indirectly based on empirical evidence. It is generally understood that they implicitly reflect, though they do not explicitly assert, causal relationships fundamental to reality, and are discovered rather than invented. Scientific laws summarize the results of experiments or observations, usually within a certain range of application. In general, the accuracy of a law does not change when a new theory of the relevant phenomenon is worked out, but rather the scope of the law's application, since the mathematics or statement representing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andrey Korotayev
Andrey Vitalievich Korotayev (; born 17 February 1961) is a Russian anthropology, anthropologist, economic history, economic historian, comparative politics, comparative political scientist, demography, demographer and sociology, sociologist, with major contributions to world-systems theory, cross-cultural studies, Near Eastern history, Big History, and mathematical modelling of social and Macroeconomics, economic macrodynamics. He is currently the Director of the Centre for Stability and Risk Analysis at the Higher School of Economics, HSE University in Moscow, and a Senior Research Professor at the Center for Big History and System Forecasting of the Institute of Oriental Studies of the Russian Academy of Sciences, Institute of Oriental Studies as well as in the Institute for African Studies of the Russian Academy of Sciences. In addition, he is a senior research professor of the International Laboratory on Political Demography and Social Macrodynamics (PDSM) of the Russia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neo-malthusianism
Malthusianism is a theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline. This event, called a Malthusian catastrophe (also known as a Malthusian trap, population trap, Malthusian check, Malthusian snatch, Malthusian crisis, Point of Crisis, or Malthusian crunch) has been predicted to occur if population growth outpaces agricultural production, thereby causing famine or war. According to this theory, poverty and inequality will increase as the price of assets and scarce commodities goes up due to fierce competition for these dwindling resources. This increased level of poverty eventually causes depopulation by decreasing birth rates. If asset prices keep increasing, social unrest would occur, which would likely cause a major war, revolution, or a famine. Societal collapse is an ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malthusian Catastrophe
Malthusianism is a theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline. This event, called a Malthusian catastrophe (also known as a Malthusian trap, population trap, Malthusian check, Malthusian snatch, Malthusian crisis, Point of Crisis, or Malthusian crunch) has been predicted to occur if population growth outpaces agricultural production, thereby causing famine or war. According to this theory, poverty and inequality will increase as the price of assets and scarce commodities goes up due to fierce competition for these dwindling resources. This increased level of poverty eventually causes depopulation by decreasing birth rates. If asset prices keep increasing, social unrest would occur, which would likely cause a major war, revolution, or a famine. Societal collapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irruptive Growth
Irruptive growth is a growth pattern over time, defined by a sudden rapid growth in the population of an organism. Irruptive growth is studied in population ecology. Population cycles often display irruptive growth, but with a predictable pattern of subsequent decline. It is a phenomenon typically associated with r-strategists. Irruptive growth occurs when a species reproduces rapidly. It is especially common in large herbivores, such as pronghorn or elk (red deer), which have high fecundity and delayed density-dependent effects on recruitment. All populations show logistic growth, but in species which exhibit irruptive growth this is especially rapid. Populations of some species initially show a lack of response to density-dependent factors that limit population size as it nears the carrying capacity of the environment. The exhibition of irruptive growth is dependent on a number of elements including resource availability, degree of both interspecific and intraspecific competit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Overpopulation
Human overpopulation (or human population overshoot) is the idea that human populations may become too large to be sustainability, sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities. Since 1804, the global living human population has World population milestones, increased from 1 billion to 8 billion due to Modern medicine, medical advancements and improved agricultural productivity. Annual world population growth peaked at 2.1% in 1968 and has since dropped to 1.1%. According to the most recent Projections of population growth, United Nations' projections, the global human population is expected to reach 9.7 billion in 2050 and would peak at around 10.4 billion people in the 2080s, before decreasing, noting that fertility rates are falling worldwide. Other models agree that the population will stabilize before or after 2100. Conversely, some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Theory
In economics, economic growth is an increase in the quantity and quality of the economic goods and services that a society produces. It can be measured as the increase in the inflation-adjusted output of an economy in a given year or over a period of time. The rate of growth is typically calculated as real gross domestic product (GDP) growth rate, real GDP per capita growth rate or GNI per capita growth. The "rate" of economic growth refers to the geometric annual rate of growth in GDP or GDP per capita between the first and the last year over a period of time. This growth rate represents the trend in the average level of GDP over the period, and ignores any fluctuations in the GDP around this trend. Growth is usually calculated in "real" value, which is inflation-adjusted, to eliminate the distorting effect of inflation on the prices of goods produced. Real GDP per capita is the GDP of the entire country divided by the number of people in the country. Measurement of econ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economics
Economics () is a behavioral science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and interactions of Agent (economics), economic agents and how economy, economies work. Microeconomics analyses what is viewed as basic elements within economy, economies, including individual agents and market (economics), markets, their interactions, and the outcomes of interactions. Individual agents may include, for example, households, firms, buyers, and sellers. Macroeconomics analyses economies as systems where production, distribution, consumption, savings, and Expenditure, investment expenditure interact; and the factors of production affecting them, such as: Labour (human activity), labour, Capital (economics), capital, Land (economics), land, and Entrepreneurship, enterprise, inflation, economic growth, and public policies that impact gloss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
