Chapter 6 NORMATIVE TIME AND THE CHALLENGE OF COMMUNITY LABOR IN LOCAL EXCHANGE TRADING SCHEMES

2020 ◽  
pp. 129-154
Keyword(s):  
Author(s):  
Alessandra Molinari

Chris Wickham has recently turned his attention to the economic and social transformations of the central Middle Ages. In the same period relations between the Christian and Muslim worlds have been presented primarily in terms of holy war or raids, and hardly ever framed in economic terms. Archaeology can help to answer questions about exchange routes, systems of production and settlement patterns, and pottery provides a key element in reconstructing the complexity of pre-modern economic networks. In this paper I want to compare two case studies. I will first examine the role of Palermo in the internal economy of Sicily and beyond. Recent excavations have provided much new information on the Muslim and Christian periods in its history, and particularly on the city’s planned growth and development as a centre of pottery production and export in the tenth century. I will then turn to the archaeological evidence for Rome, which Chris has described as the most complex city between the tenth and twelfth centuries, both economically and socially, in the whole Italian peninsula. In fact, based on the material evidence, Rome was far less complex than Palermo, and unlike Milan, it failed to take off economically in the thirteenth century. Chris has suggested that the success of the latter city was due to its specialized products, local exchange system and connections with a hierarchy of smaller settlements in the locality. Whilst the archaeological evidence for Milan is much scarcer, these features can usefully be tested as a model against which to compare other cities. Comparing Rome and Palermo it is the Sicilian city that can be said to have had the more vibrant economy, with its exports to multiple rural centres some distance away. Whilst a recent conference has underlined the existence of specialized artisans serving Rome’s elite and its numerous pilgrims, unlike Palermo it did not base its economy on production and mercantile activities.


1972 ◽  
Vol 6 (12) ◽  
pp. 4367-4370 ◽  
Author(s):  
J. F. Janak ◽  
A. R. Williams ◽  
V. L. Moruzzi

2002 ◽  
Vol 1 (5) ◽  
pp. 319-327 ◽  
Author(s):  
M. P. Rols ◽  
M. Golzio ◽  
B. Gabriel ◽  
J. Teissié

Electric field pulses are a new approach for drug and gene delivery for cancer therapy. They induce a localized structural alteration of cell membranes. The associated physical mechanisms are well explained and can be safely controlled. A position dependent modulation of the membrane potential difference is induced when an electric field is applied to a cell. Electric field pulses with an overcritical intensity evoke a local membrane alteration. A free exchange of hydrophilic low molecular weight molecules takes place across the membrane. A leakage of cytosolic metabolites and a loading of polar drugs into the cytoplasm are obtained. The fraction of the cell surface which is competent for exchange is a function of the field intensity. The level of local exchange is strongly controlled by the pulse duration and the number of successive pulses. The permeabilised state is long lived. Its lifetime is under the control of the cumulated pulse duration. Cell viability can be preserved. Gene transfer is obtained but its mechanism is not a free diffusion. Plasmids are electrophoretically accumulated against the permeabilised cell surface and form aggregates due to the field effect. After the pulses, several steps follow: translocation to the cytoplasm, traffic to the nucleus and expression. Molecular structural and metabolic changes in cells remain mostly poorly understood. Nevertheless, while most studies were established on cells in culture ( in vitro), recent experiments show that similar effects are obtained on tissue ( in vivo). Transfer remains controlled by the physical parameters of the electrical treatment.


2003 ◽  
Vol 13 (08) ◽  
pp. 1185-1217 ◽  
Author(s):  
Olivier Bokanowski ◽  
Benoît Grebert ◽  
Norbert J. Mauser

We deal with local density approximations for the kinetic and exchange energy term, ℰ kin (ρ) and ℰ ex (ρ), of a periodic Coulomb model. We study asymptotic approximations of the energy when the number of particles goes to infinity and for densities close to the constant averaged density. For the kinetic energy, we recover the usual combination of the von-Weizsäcker term and the Thomas–Fermi term. Furthermore, we justify the inclusion of the Dirac term for the exchange energy and the Slater term for the local exchange potential.


2002 ◽  
Vol 358 (1-2) ◽  
pp. 43-50 ◽  
Author(s):  
WanZhen Liang ◽  
Yihan Shao ◽  
Christian Ochsenfeld ◽  
Alexis T. Bell ◽  
Martin Head-Gordon

1985 ◽  
Vol 16 (4) ◽  
pp. 204-208 ◽  
Author(s):  
N. Bhana

South African investors have been precluded from investing in foreign securities by the Exchange Control Regulations of 1961. Furthermore, the monetary policy pursued by the authorities has resulted in an inefficient financial market. Investments on the capital market have not earned satisfactory real rates of return, and prices on the JSE appear to have been driven to artificial heights. The De Kock Commission of Inquiry has proposed several recommendations which will have far-reaching consequences for investors in South Africa. The proposal of market-related interest rates and the abolition of prescribed investments by institutional investors is likely to result in long-term securities earning substantially higher real rates of return. The relaxation of exchange control for both direct and portfolio investment is likely to stem the flow of funds into the JSE. Investment funds can be expected to flow between the JSE and the various foreign equity markets depending on the economic prospects in the different countries. The high foreign exchange cost and poor liquidity of the local exchange market has been an obstacle to investors in foreign securities. The creation of a larger and more efficient foreign exchange market is likely to facilitate international portfolio diversification in South Africa.


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