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161.
The characterization of various samples of white marble from the archaeological site of Tharros (Sardinia) is the starting point for the reexamination of the capabilities of electron spin resonance (ESR) spectroscopy as a tool for identifying the quarries of origin of ancient marble artefacts. Existing methods and data bases are employed for the assignment of our samples, but also reviewed to see if a more extensive use of the technique is feasible. It turns out that ESR spectroscopy, coupled with other available methods, may readily provide valuable information, often yielding the final answer to the problem of marble provenance. However, it is also clear that much work has still to be done to standardize the data collection and analysis procedures and to expand the available data base. 相似文献
162.
Norman R. Cloutier 《Journal of regional science》1997,37(3):459-478
The empirical analysis in this paper explores the interurban variation in family income distribution. The results point to increasing urban development, rising female-headship, a widening educational distribution, and changes in the industrial and occupational mix as major contributing factors to rising inequality. However, the increase in the relative number of multiple worker families was a significant mitigating force to rising inequality. A decomposition of 1979 and 1989 cross-sectional models revealed that while changes in urban family and industrial characteristics have been sources of rising inequality, there has been significant structural change in the urban models acting to decrease inequality. 相似文献
163.
Philip R. Israilevich Geoffrey J. D. Hewings Michael Sonis & Graham R. Schindler 《Journal of regional science》1997,37(4):565-590
The sophistication of regional economic models has been demonstrated in numerous ways, most recently in the form of linking several modeling systems or in the expansion in the number of equations that can be manipulated successfully to produce impact analyses or forecasts. In this paper, an alternative perspective is employed. What do regional macro-level forecasts indicate about the process of structural change? A new methodology is illustrated that enables analysts to make forecasts of detailed structural change in the interindustry relations in an economy. Using a regional econometric input-output model developed for the Chicago metropolitan region, derived input-output tables are extracted for the period 1975–2016. These tables are then analyzed to determine the forecasted direction of structural changes for the region. The innovation illustrated here is based on a model that exploits the general equilibrium spirit of computable general equilibrium models through the adjustment of input coefficients to clear markets. 相似文献
164.
Macrophysical climatic modeling (MCM) is based on the relationship between large-scale atmospheric dynamics and synoptic climatology to develop simulations of late Pleistocene and Holocene climate in specific localities. Climatic events are calculated at 200-year intervals for the last 14,000 and 500 years for the period from 14,000 to 40,000 B.P. The model has been applied to more than 200 localities in Africa. We present examples from different parts of the continent at locations of archaeological significance. The results indicate that the transition from glacial maximum to postglacial conditions shows both temporal and inter- and intraregional variability. In addition to long-term differences among early, middle, and late Holocene climatic regimes, the model also shows incidences of sharp, abrupt events at some intervals. The applications of MCM invite comparison with inferences based on proxy data and assist in formulating and cross-examining socioecodynamic models based on climatic change, e.g., the continuity of cultural interactions along the Mediterranean littoral, the emergence and spread of cattle pastoralism, and the depopulation of the Sahara during the glacial maximum. 相似文献
165.
This paper extends a compartmental epidemiological model for HIV transmission and AIDS incidence to include hierarchical and expansion spatial diffusion. An implication of the resultant model is that hierarchical diffusion causes the large infection growth rates of densely populated areas at the top of the central places hierarchy to “chain” down and dominate small local growth rates during the exponential-growth phase of the epidemic. Also, hierarchical diffusion causes a high transient growth rate in the first few years of a local epidemic. The spatial compartmental model fits observed AIDS incidence spatial diffusion patterns in Ohio reasonably well. 相似文献
166.
ABSTRACT. This paper proposes a new method for estimating a monthly regional production model. The technique involves treating the region's monthly industrial output as a latent variable, which is in turn a function of capital (prosed by energy usage) and labor inputs. Annual observations on regional value added correspond to the summation of the unobservable monthly series over the 12 months, while changes in the national Industrial Production index help infer the series' month-to-month fluctuations. The model is estimated using the Kalman filter and the method of maximum likelihood. The estimates are used to compute monthly indices of regional value added for 15 individual 2-digit industries, and for the aggregate manufacturing sector in the Seventh Federal Reserve District. In a comparison of out-of-sample forecasting accuracy, the mixed-frequency model outperforms both the traditional parametric Cobb-Douglas and nonparametric Atlanta methods over the 1988–89 forecasting horizon. 相似文献
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