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51.
Medic (Medicago spp.) pastures are widely grown in rotation with dryland cereal crops in Mediterranean climate zones of Australia. Attempts since the 1960's to introduce this system to Mediterranean west Asia and north Africa (the native region of medic) have not lead to significant adoption; farmers in the region recognize medic, but as a weed and natural pasture plant. This first detailed economic evaluation of the rotational medic system was conducted using a whole-farm linear programming model based on the agricultural system of north-west Syria. The model represents in detail impacts of rotation on yields, labor requirements of alternative farm activities, availability of family and hired labor, subsistence income requirements, livestock feed sources and uses at different times and a choice of sheep stocking rates. Biological data for the analysis are based on a large six-year cropping and grazing experiment near Aleppo on terra-rossa soil with rainfall mainly in winter and averaging about 330 mm annually. The trial compared a dryland medic-wheat system and traditional two-year rotations of wheat with: fallow, watermelon, lentil and vetch. Results indicate that, given current prices and yields from the trial, medic is less profitable than traditional rotations. The model was used to investigate situations in which medic would be economically preferred. Selection of a medic rotation by the model was found to be particularly sensitive to the area of the farm and the price of labor. On small farms, labor availability per hectare is high, favouring the production of labor intensive crops such as lentil and watermelon. On larger farms, labor costs of these enterprises are substantial, increasing the relative profitability of medic, especially if labor prices increase. Interestingly, the relative desirability of medic is more sensitive to its impact on subsequent wheat crops than to the level of pasture production. We also found that modest increases in the prices of sheep products (especially milk) have a major impact on the economic performance of medic. These insights will allow improved focusing and targeting of future research and extension activities.  相似文献   
52.
J. J. Graafland 《De Economist》1992,140(4):501-514
Summary In most traditional macroeconomic models for The Netherlands the wage equation is specified by a Phillips curve, in which wage growth is negatively related to the unemployment rate. This paper shows, however, that wage formation can better be described by the so-called wage curve, in which the wage level, instead of wage growth, depends negatively on the unemployment rate.The author thanks S.K. Kuipers and D.A.G. Draper and other colleagues of the Central Planning Bureau for their useful comments.  相似文献   
53.
This study examines the effects of demographic characteristics on ethical perceptions. While earlier research has produced conflicting results regarding the predictive power of these variables, significant and definite insights were obtained with proper controls. The following predictors of ethical attitudes are examined: age, gender, marital status, education, dependent children status, region of the country and years in business, while controlling for job status. A nation-wide random sample of employees was used in obtaining a response rate of fifty-three percent (total n of 423). Indices of aspects of business ethical attitudes were constructed using factor analysis. Linear multiple regression analysis indicated the significant predictive variables. Age was found to be a most-significant predictor. Older workers had stricter interpretations of ethical standards. Gender and region predicted attitudes about job-discrimination practices only, with women and persons from the Midwest most strongly opposed to the practice. All the other variables proved to be unreliable ethics predictors.Paul Serwinek is a research affiliated with Wayne State University. He has done extensive research in business management and consulting work in the field of insurance agency employee job satisfaction.SPSS PC Plus Computer Program used.  相似文献   
54.
This article analyses the effects of action aimed at narrowing the gap between South Africa's ‘two agricultures’, specifically the effects of the Farmer Support Programme (FSP) on structural aspects of maize production under different marketing policies. This is done by assembling a sectoral linear programming model of the South African summer-rainfall grain-producing area. The emphasis is on the inclusion of supply, demand and production risk. Results show that the effects of a successful FSP on specific interest groups, e.g. consumers of a specific product, or producers in a specific region, depend on the marketing policy followed, as well as on the effectiveness of the FSP. The analysis accentuates the interrelationships in South African crop production and illustrates how past policies ignored regional comparative advantages, distorted regional development and affected social welfare.  相似文献   
55.
The purpose of this study is to build on the results recently obtained by Poznanski (1990). First, the estimation technique is generalised by removing both the symmetric restrictions and the effects of autocorrelated errors that are present in simple logistic functions. Secondly, attention is drawn to the existence and consequences of multicollinearity when non linear techniques are applied to a general exponential. Thirdly, an attempt is made to quantify the importance of market structure and time lags in adoption as determinants of diffusion speed. Finally, a comparison between these generalised results and Poznanski's is made.The study concludes that, by generalising the estimation technique, some significant changes take place. Changes occur in the ordering and magnitude of diffusion speeds, especially amongst the developing and centrally planned economies. Changes also occur in the nature of the diffusion process, and in the importance attributed to market structure and diffusion lags in determining the rate of diffusion. It is also shown that, for some countries, multicollinearity imposes constraints on the type of generality that can be obtained.  相似文献   
56.
57.
Editorial     
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58.
At present, our society and its social security system are not prepared to cope with the challenges resulting from the continuous increase of life expectancy. The traditional concept of disease has to be modified for serving the special needs of the elderly. The optimistic compression of disease theory is an intriguing model, but lacks prove by available data. The anti-aging boom diverts the focus from the social and financial burden that will be unevitably caused by long-term care in the future. If there will not be an — up to now unforeseeable — breakthrough in research, particularly dementia will have an enormous impact on social cost which is often underestimated.  相似文献   
59.
60.
Efficient Liability Rules: Complete Characterization   总被引:5,自引:0,他引:5  
Received May, 18, 2000; revised version received March, 19, 2001  相似文献   
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