The Situation Of Zimbabwe's Large Commercial Farmers In A Period Of Structural Change

An AEE Working Paper.This study was undertaken as part of the research programme of the Department of Agricultural Economics and Extension of the University of Zimbabwe in 1990/91. Preparations and pretests for the interview were carried out in 1990. The actual field work with interviews of a sample of 52 large commercial farmers took place from February to April 1991 in four selected areas: Wedza, Marondera, Glendale north of Harare, Masvingo East , and Manila near Plumtree in Matabeleland. These areas, representing various important farm systems of Zimbabwe, were selected after consultation with the Head Office of the Commercial Farmers Union, Harare. In each area between 10 to 16 farmers were interviewed using a formal questionnaire. The interview took between 90 and 120 minutes. The selection of the sub-samples was done together with the Chairman of-the respective Farmers Association, using as criteria the main production system, size of farm, age of farmer.The study was financially supported by a research grant of the University of Zimbabwe and by the Department of Agricultural Economics and Extension of the University which also made its secretarial and computer services available for a fast data processing and report writing

Grenzen der Stabilitätsintervalle für die KMD-Regelprozesse

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Does wage rigidity really exist? New evidence from US panel data

Downward nominal wage rigidity (DNWR) could prevent real wage adjustments in times of low inflation rates. Nominal wage rigidity based on annual wages can at least be reduced, if the number of working hours is considered. This leads to a lower degree of DNWR in hourly wage changes. In this paper, we use a histogram-location approach to investigate to what extent annual as well as hourly wages are subject to downward nominal wage rigidity. Using data from the Panel Study of Income Dynamics (PSID) we find that annual wage changes exhibit a substantially higher level of wage rigidity than hourly wage changes which also holds for males compared to females. --Wage Rigidity,Histogram-Location Approach

Die Halbwertzeit einer Störungserosion

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Eine Methode zur Schätzung der Rückkopplungsparameter im Koordinationsmängel: Diagnosekonzept

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The Influence of Collusion on Price Changes: New Evidence from Major Cartel Cases

In this paper, we compare the distribution of price changes between collusive and noncollusive periods for ten major cartels. The first moments focus on previous research. We extend the discussion to the third (skewness) and fourth (kurtosis) moments. However, none of the above descriptive statistics can be considered as a robust test allowing a differentiation between competition and cartel. Therefore, we implement the Kolmogorov-Smirnov test. According to our results, 8 out of 10 cartels were successful in controlling the market price for a number of years. The proposed methodology may be used for antitrust screening and regulatory purposes.Cartel detection, collusion, competition policy

Comparing cartel behavior: A simulation analysis with the System of Cartel Markers (SCM)

This work simulates the behavior of a price, quota and regional cartel in terms of indicators such as price, capacity and rate of return. As a first step the specific behavior patterns of each cartel are indicated in a graphical analysis before a comparison to a competitive benchmark has been implemented. In a second step simulation data has been applied to the System of Cartel Markers (SCM) invented by Blanckenburg and Geist. The SCM uses empirical correlation and stationarity of indicators to provide empirical evidence for cartel behavior. For the simulated cartel data the SCM delivered consistent results which underline its functionality for simulation purposes. --

The circular nutrient economy of terrestrial ecosystems and the consequences for rock weathering

Earth’s biosphere is thought to exert a substantial influence on regolith evolution and chemical weathering rates. However, ecosystems are also highly efficient at retaining and recycling nutrients. Thus, when the ecological demand for rock-derived nutrients (e.g., P, Ca, K) exceeds the rates of regolith supply, ecological retention and recycling strategies can minimize nutrient limitations. To evaluate the balance between nutrient recycling and new nutrient input, we combined a plant model that drives growth according to foliar P levels with a weathering model that includes regolith rejuvenation via erosion and export via chemical weathering according to water flow, regolith thickness, mineral dissolution rates, secondary minerals, and nutrient storage in organic and mineral phases. We find that plant growth is strongly dependent on the total regolith nutrient inventory, resulting in a strong correlation between plant productivity and erosion. Increased water export or decreased regolith thickness diminish the total inventory of nutrient corresponding to lower rates of recycling and lower plant growth. In contrast, purported biogenic drivers of weathering, such as enhanced mineral dissolution, only support higher growth rates at high erosion rates. At erosion rates typical of the global land surface, more rapid mineral dissolution combined with enhanced formation of secondary minerals, depletes the inventory of mineral P, resulting in no benefit for plant growth. We also find that the increased chemical weathering export does not scale directly with plant growth. For example, accelerated mineral weathering does increase chemical weathering export but not potential plant growth. Conversely, thicker regolith is associated with a small increase in weathering export, but a large increase in potential plant growth. Collectively, when plant growth is coupled to regolith weathering our calculations suggest that plant productivity is not directly correlated with silicate weathering fluxes, and that biotic drivers of silicate weathering may only be effective at high erosion rates not typical at the Earth’s surface

Exakte Bestimmung der Stabilitätsbedingungen von Marktprozessen auf der Basis des Koordinationsmängel-Diagnosekonzepts und des Schur-Theorems

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