1,721,078 research outputs found
Solutions to Donaldson's Hyperkähler Reduction on a Curve
Full text linkWe study an infinite-dimensional hyperkähler reduction introduced by Donaldson and associated with the constant scalar curvature equation on a Riemann surface. It is known that the corresponding moment map equations admit special solutions constructed from holomorphic quadratic differentials. Here we obtain a more general existence result and so a larger hyperkähler moduli space
Inducing Efficiency in the Use of Foreign Aid: The Case for Incentive Mechanisms
No full textIn this article we point out that one of the main problems in foreign aid allocation is the efficient use of these funds: as resources available for foreign aid are intrinsically scarce, their efficient use would be in the interest of donors, and especially recipient countries. The aim of this paper is to show how it is possible to design incentive schemes which, by relating the allocation of aid to the way it is used, may induce the recipient country to use these resources appropriately. We discuss potential benefits and problems of different contractual forms, showing how comparing the performances of different countries may help to design optimal incentive mechanisms. Finally, we illustrate a proposal of performance conditioning of the grant element, which may help in tackling the efficiency problem. © 1992, Taylor & Francis Group, LLC. All rights reserved
Regulating a multi-utility firm
No full textWe study the regulation of a multi-utility, i.e. a utility firm that is also active in a competitive,
unregulated sector. If the firm conducts its activities in the two markets jointly, it enjoys
economies of scope whose magnitude is the firm’s private information, unknown either to the
regulator or to the rival firms. We jointly characterize the unregulated market outcome (with
price and quantity competition) and optimal regulation. Accounting for the several effects of
regulation on the unregulated market, we show the existence of an informational externality, in
that regulation provides useful information to the rival firms.
Although joint conduct of multi-utility’s activities generates scope economies, it also brings
private information to the multi-utility, so that regulation is less efficient and the unregulated
market too may be adversely affected. Nevertheless, we show that allowing the multi-utility
to integrate productions is (socially) desirable, unless joint production is characterized by diseconomies
of scope
Footloose monopolies: regulating a "national champion"
No full textWe analyze the design of optimal regulation of a domestic monopolist that also competes
in an unregulated foreign market. We show how foreign activities by the regulated firm affect
domestic regulation, consumers’ surplus and firm’s profits. Although expansion in unregulated
foreign markets amplifies the regulatory distortions that are caused by the regulator’s limited
information, we also show that allowing the firm to compete abroad does not necessarily harm
domestic consumers and we analyze if and when the firm’s decision to expand abroad does in
fact coincide with consumers’ interests in the regulated market
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Investigation of biomechanical response of PDL by using an hyperelastic formulation
No full textThe work pertains to the formulation of a numerical model for
the investigation of biomechanical response of the periodontal
ligament [1] and of the evaluation of displacement behaviour
of natural teeth under different loadings.
Tissue material constitutive models are defined on the
basis of experimental data, deduced from tests on PDL
samples of animals. In vivo tests [2,3] are considered for
humans, leading to macroscopic data as forces and
displacements monitored for a specific tooth, and used to
identify elastic and viscous characteristics.
Hyperelastic isotropic and/or anisotropic models [4] are
developed for describing the mechanics of the PDL tissue,
under specific loading conditions admitting elastic response.
In the present investigation, results are validated by
comparison with experimental data on human central incisors
under intrusive forces.
Time-dependent behaviour of the PDL [5] can be
considered by means of visco-elastic constitutive models,
investigating the mobility of human teeth under application of
transversal forces of low magnitude
Flexibility choices and oligopolistic competition in an evolutionary environment
No full textWe study the problem of the endogenous choice of technology when the level of demand is uncertain. Firms can choose either a 'flexible' technology, which allows them to vary the cost structure, or a 'rigid' technology, which in periods of high demand is more efficient. Firms tend to adopt the (ex ante) more rewarding technology. We develop a full dynamic model with given number of firms as well as with entry and exit, and with perfect foresight as well as with myopic firms. We show that firms with different technologies can coexist in the market in a permanent way, and characterise the parameter configurations leading to such results
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