The Quadratic Transportation Problem as a Model of Interregional Migration Patterns

Spatial interaction models have played an important role in two tasks in the Human Settlements and Services Area. In the Public Facilities Location Task they have been used to represent the locational behavior of establishments and households. In the Urban Change Task they have been used to describe internal migration patterns. In this paper, Waldo Tobler introduces a new spatial interaction model and outlines some of its properties. Variants of the basic model are noted and a computer listing is provided for readers wishing to explore the usefulness of the model as a descriptor of movement patterns

Analysis of Three Interaction Matrices

The first matrix represents the cross-citations between nineteen business and economic journals. The second matrix consists of intersectoral job changes in Belgium. The third matrix indicates the amount of interaction between retail establishments, as indicated by customer movements from one establishment to another

Commodity Fields

The accompanying maps were produced in conjunction with a larger study of spatial interaction. They are extracted here because they have as a common theme the movement of commodities

Spatial Interaction Patterns

An algebraic examination of spatial models leads to the conclusion that a convenient description of the pattern of flows implicit in a geographical interaction table is obtained by displaying a field of vectors computed from the relative net exchanges. The vector field approximates the gradient of a scalar potential, and this may be invoked to explain the flows. The method can be applied to asymmetrical tables of a non-geographical nature

A Preliminary Analysis of the Spread of the Depression

The closure of banks at the time of the depression can be regarded as an economic innovation which diffused throughout our society, culminating in the national bank holiday. The propagation of such events would seem likely to reveal the structure of the system. One may postulate that the general organization of the society has not changed in the last forty years, although the banking industry has been modified in its details. One would expect that technological innovations in today's society spread in a manner analogous to bank closures in that earlier period, probably at a somewhat accelerated rate

Patterns of trophic resource use and individual specialization in two species of darters (Etheostoma: Percidae)

Citation: Hopper, G. W., & Tobler, M. (2016). Patterns of trophic resource use and individual specialization in two species of darters (Etheostoma: Percidae). Evolutionary Ecology Research, 17(1), 53-73. Retrieved from ://WOS:000384803400004Background: Species are often grouped into distinct trophic guilds based on their average diets. But the diets of populations may be highly variable through space and time. Even populations that are described as foraging on a wide variety of dietary resources are often comprised of individuals with very narrow dietary preferences, and such individual specialization may vary among populations as a function of local conditions. River gradients provide subtle variation in environmental conditions, so that stream fishes that occur along such gradients may be studied to reveal how environmental conditions shape trophic resource use and individual specialization. Questions: How does trophic resource use vary among species and populations? Does it correlate with local resource availability? What variability exists in individual dietary widths among populations and species? May we attribute variation in individual dietary widths among sites to any environmental variation? Organisms: Two sympatric stream fishes (Etheostoma flabellare and E. spectabile, Percidae) from nine locations in Oklahoma, USA. Methods: We analysed gut contents of the fish. We measured individual dietary width in each of the populations. We also measured resource diversity and densities as well as the number of competitor species. Results: We found significant variation in the diets between species and among populations of the same species. Furthermore, most populations consisted of individuals with narrow dietary width (i.e. high individual dietary specialization). Variation in individual dietary widths in populations of E. flabellare was correlated with invertebrate density and the number of competitor species, and in E. spectabile with the number of invertebrate species and invertebrate density

Patterns of trophic resource use and individual specialization in two species of darters (Etheostoma: Percidae)

Citation: Hopper, G. W., & Tobler, M. (2016). Patterns of trophic resource use and individual specialization in two species of darters (Etheostoma: Percidae). Evolutionary Ecology Research, 17(1), 53-73. Retrieved from ://WOS:000384803400004Background: Species are often grouped into distinct trophic guilds based on their average diets. But the diets of populations may be highly variable through space and time. Even populations that are described as foraging on a wide variety of dietary resources are often comprised of individuals with very narrow dietary preferences, and such individual specialization may vary among populations as a function of local conditions. River gradients provide subtle variation in environmental conditions, so that stream fishes that occur along such gradients may be studied to reveal how environmental conditions shape trophic resource use and individual specialization. Questions: How does trophic resource use vary among species and populations? Does it correlate with local resource availability? What variability exists in individual dietary widths among populations and species? May we attribute variation in individual dietary widths among sites to any environmental variation? Organisms: Two sympatric stream fishes (Etheostoma flabellare and E. spectabile, Percidae) from nine locations in Oklahoma, USA. Methods: We analysed gut contents of the fish. We measured individual dietary width in each of the populations. We also measured resource diversity and densities as well as the number of competitor species. Results: We found significant variation in the diets between species and among populations of the same species. Furthermore, most populations consisted of individuals with narrow dietary width (i.e. high individual dietary specialization). Variation in individual dietary widths in populations of E. flabellare was correlated with invertebrate density and the number of competitor species, and in E. spectabile with the number of invertebrate species and invertebrate density

Herding in Financial Behaviour: A Behavioural and Neuroeconomic Analysis of Individual Differences

Experimental analyses have identified significant tendencies for individuals to follow herd decisions, a finding which has been explained using Bayesian principles. This paper outlines the results from a herding task designed to extend these analyses using evidence from a functional magnetic resonance imaging (fMRI) study. Empirically, we estimate logistic functions using panel estimation techniques to quantify the impact of herd decisions on individuals' financial decisions. We confirm that there are statistically significant propensities to herd and that social information about others' decisions has an impact on individuals' decisions. We extend these findings by identifying associations between herding propensities and individual characteristics including gender, age and various personality traits. In addition fMRI evidence shows that individual differences correlate strongly with activations in the amygdala – an area of the brain commonly associated with social decision-making. Individual differences also correlate strongly with amygdala activations during herding decisions. These findings are used to construct a two stage least squares model of financial herding which confirms that individual differences and neural responses play a role in modulating the propensity to herd.amygdal

Herding in Financial Behaviour

Experimental analyses have identified significant tendencies for individuals to follow herd decisions, a finding which has been explained using Bayesian principles. This paper outlines the results from a herding task designed to extend these analyses using evidence from a functional magnetic resonance imaging (fMRI) study. Empirically, we estimate logistic functions using panel estimation techniques to quantify the impact of herd decisions on individuals' financial decisions. We confirm that there are statistically significant propensities to herd and that social information about others' decisions has an impact on individuals' decisions. We extend these findings by identifying associations between herding propensities and individual characteristics including gender, age and various personality traits. In addition fMRI evidence shows that individual differences correlate strongly with activations in the amygdala ﾖ an area of the brain commonly associated with social decision-making. Individual differences also correlate strongly with amygdala activations during herding decisions. These findings are used to construct a two stage least squares model of financial herding which confirms that individual differences and neural responses play a role in modulating the propensity to herd