19,050 research outputs found

    The efficiency of plankton in the utilization of the sun radiation [Translation from: Briroda, 12, 29-35, 1948]

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    The efficiency of utilisation of the sun's radiation by natural communities has not been properly demonstrated with what so far has been obtained of reliable values, and it represents a great interest in many respects. A systematic study of the biotic balance of lakes was done in the course of a succession of summers starting in 1932, extensive material was obtained, which permitted to compute a value fear the utilisation of the sun's radiation by plankton in lakes, and to compare this with corresponding values for marine plankton and terrestrial vegetation

    An efficient asymptotic extraction approach for the green's functions of conformal antennas in multilayered cylindrical media

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    Asymptotic expressions are derived for the dyadic Green's functions of antennas radiating in the presence of a multilayered cylinder, where analytic representation of the asymptotic expansion coefficients eliminates the computational cost of numerical evaluation. As a result, the asymptotic extraction technique has been applied only once for a large summation order nn. In addition, the Hankel function singularity encountered for source and evaluation points at the same radius has been eliminated using analytical integration

    Institutions and economic research: a case of location externalities on agricultural resource allocation in the Kat River basin, South Africa

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    The Physical Externality Model is used to illustrate the potential limitations of blindly adopting formal models for economic investigation and explanation in varied geographical contexts. As argued by institutional economists for the last hundred years the practice limits the value and relevance of most general economic inquiry. This model postulates that the geographical location of farmers along a given watercourse, in which water is diverted individually, leads to structural inefficiencies that negatively affect the whole farming community. These effects are felt more severely at downstream sites and lead to a status quo where upstream farmers possess relative economic and political advantages over their counterparts elsewhere. In the study of the Kat River basin these predictions appear to be true only in as far as they relate to legal and political allocations and use of water resources. In terms of lawful uses of land resources aimed at expanding citrus production, the model’s predictions are not met. The status quo is however fully explained by the implications of having adopted formal water scheduling rights by upstream farmers as well as other geographical factors. Hence, the case for investigating the effects of important institutions within general economic research is strengthened.institutions, water allocation, physical externality, Kat River Valley,

    A Game Theoretic Framework for Cooperative Benefits in South Africa’s Land Redistribution Process: A Case of Northern Kwa-Zulu Natal Sugarcane Farmland Transfers

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    A good indicator of successful farm redistribution cases has to be the continuation of viable productivity rates in their post transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to argue that cooperation among key stakeholders, which could be enforced through long term contracts between a land buyer, sellers and new owners, would lead to higher productivity levels and other benefits. Additional benefits would, for example, include market related prices paid by a buyer. Sugarcane farm transfer cases from two municipality districts in KwaZulu Natal province are used to show that the productivity rates in post transfer periods of cooperative land sales were more than 10% higher than the rates observed before such transfers. At the opposite end of the scale, the productivity rates in noncooperative land sales dropped by 16% after land takeovers. Furthermore, the prices paid for farms that became less productive after transfers were higher by more than 40% compared to those paid for productive farms. The cases illustrate the values of cooperative strategies in economic transactions.Sugarcane, farms, redistribution, productivity, cooperation, games, Land Economics/Use, Research Methods/ Statistical Methods,

    Mediator Languages - a Proposal for a Standard

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    Inhibition of hepatitis C virus RNA replication by ISG15 does not require its conjugation to protein substrates by the HERC5 E3 ligase

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    Chronic infection of the liver by hepatitis C virus (HCV) induces a range of host factors including IFN-stimulated genes such as ISG15. ISG15 functions as an antiviral factor that limits virus replication. Previous studies have suggested that ISG15 could influence HCV replication in both a positive and a negative manner. In this report, we determined the effect of ISG15 on HCV RNA replication in two independent cell lines that support viral genome synthesis by inhibiting ISG15 expression through small interfering RNA, short-hairpin RNA and CRISPR/Cas9 gene knockout approaches. Our results demonstrated that ISG15 impairs HCV RNA replication in both the presence and absence of IFN stimulation, consistent with an antiviral role for ISG15 during HCV infection. ISG15 conjugation to protein substrates typically requires the E3 ligase, HERC5. Our results showed that the inhibitory effect of ISG15 on HCV RNA replication does not require its conjugation to substrates by HERC5

    The effects of economic incentives in controlling pollution in the South African Leather Industry

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    Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control†techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.Environmental Economics and Policy,

    Description and texts for the auxiliary programs for processing video information on the YeS computer. Part 3: Test program 2

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    The functions were discribed and the operating instructions, the block diagram and the proposed versions are given for modifying the program in order to obtain the statistical characteristics of multi-channel video information. The program implements certain man-machine methods for investigating video information. It permits representation of the material and its statistical characteristics in a form which is convenient for the user
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