The Spatial Diffusion of Technology

Productivity and Spatial Diffusion of Technology in Greece: An Empirical Analysis

10.51240/jibe.2007.1.8 ◽

2007 ◽

Vol 8 (1) ◽

pp. 105-124

Author(s):

Serafeim Polyzos ◽

Dionyssis Minetos ◽

Labros Sdrolias

Keyword(s):

Spatial Scale ◽

Spatial Diffusion ◽

Geographical Distance ◽

Economic Sectors ◽

Diffusion Of Technology ◽

Regional Inequalities ◽

Secondary Sector ◽

Spatial Differences ◽

The One ◽

Basic Determinant

A great number of studies concerning Greece and other countries have indicated that there are important differences in productivity of economic sectors amongst the different regions. This article focuses on the enterprises that employ more than 20 persons, analyses the observed differences in the productivity of the secondary sector and investigates the influence of technology on the configuration of enterprises??productivity. The spatial scale of analyses is the one defined by the Greek prefectural administrative level. The basic determinant factors of productivity are concretely described and the relationships between technology and productivity and between technology and geographical distance are estimated. The article concludes by commenting on both the existing spatial differences in productivity and the diffusion of technology in the light of their influence on regional inequalities in Greece.

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Saturn's E, G and F rings: modulated by the plasma sheet

International Astronomical Union Colloquium ◽

10.1017/s0252921100101666 ◽

1984 ◽

Vol 75 ◽

pp. 597

Author(s):

E. Grün ◽

G.E. Morfill ◽

T.V. Johnson ◽

G.H. Schwehm

Keyword(s):

Solar Wind ◽

Direct Contact ◽

Transport Processes ◽

Time Variable ◽

Dust Particles ◽

Spatial Diffusion ◽

Drag Forces ◽

Orbit Perturbation ◽

Time Variations ◽

F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

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Numerical Analysis of the Age-Sex-Structured Population Dynamics Taking into Account Spatial Diffusion

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.4.15116 ◽

2005 ◽

Vol 10 (4) ◽

pp. 365-381 ◽

Cited By ~ 1

Author(s):

Š. Repšys ◽

V. Skakauskas

Keyword(s):

Population Dynamics ◽

Numerical Analysis ◽

Population Model ◽

Local Stability ◽

Deterministic Model ◽

Random Mating ◽

Spatial Diffusion ◽

Neumann Problems ◽

Structured Population ◽

Structured Population Dynamics

We present results of the numerical investigation of the homogenous Dirichlet and Neumann problems to an age-sex-structured population dynamics deterministic model taking into account random mating, female’s pregnancy, and spatial diffusion. We prove the existence of separable solutions to the non-dispersing population model and, by using the numerical experiment, corroborate their local stability.

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