10,095 research outputs found

    Liquidity measures and cost of trading in an illiquid market

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    We provide the first in-depth study of trading on the Ukrainian stock exchange, using trade-by-trade data. Although Ukraine has some large listed companies, the market is quite illiquid. We study the efficiency of five liquidity measures in the market. The proportion of no-trading days is the most reliable of the five, while turnover, which is widely used in the literature, is a poor measure. On trading cost, trades in all size categories are executed within the quoted spread, as in other dealership markets, with medium-sized trades being the cheapest. The cost of sales is higher than the cost of purchases under all market conditions

    Convergence of simple adaptive Galerkin schemes based on h − h/2 error estimators

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    We discuss several adaptive mesh-refinement strategies based on (h − h/2)-error estimation. This class of adaptivemethods is particularly popular in practise since it is problem independent and requires virtually no implementational overhead. We prove that, under the saturation assumption, these adaptive algorithms are convergent. Our framework applies not only to finite element methods, but also yields a first convergence proof for adaptive boundary element schemes. For a finite element model problem, we extend the proposed adaptive scheme and prove convergence even if the saturation assumption fails to hold in general

    Geo-additive models of Childhood Undernutrition in three Sub-Saharan African Countries

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    We investigate the geographical and socioeconomic determinants of childhood undernutrition in Malawi, Tanzania and Zambia, three neighboring countries in Southern Africa using the 1992 Demographic and Health Surveys. We estimate models of undernutrition jointly for the three countries to explore regional patterns of undernutrition that transcend boundaries, while allowing for country-specific interactions. We use semiparametric models to flexibly model the effects of selected so-cioeconomic covariates and spatial effects. Our spatial analysis is based on a flexible geo-additive model using the district as the geographic unit of anal-ysis, which allows to separate smooth structured spatial effects from random effect. Inference is fully Bayesian and uses recent Markov chain Monte Carlo techniques. While the socioeconomic determinants generally confirm what is known in the literature, we find distinct residual spatial patterns that are not explained by the socioeconomic determinants. In particular, there appears to be a belt run-ning from Southern Tanzania to Northeastern Zambia which exhibits much worse undernutrition, even after controlling for socioeconomic effects. These effects do transcend borders between the countries, but to a varying degree. These findings have important implications for targeting policy as well as the search for left-out variables that might account for these residual spatial patterns

    Impact of irreversibility and uncertainty on the timing of infrastructure projects

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    This paper argues that because of the irreversibility and uncertainty associated with Build - Operate - Transfer (BOT) infrastructure projects, their financial evaluation should also routinely include the determination of the value of the option to defer the construction start-up. This ensures that project viability is comprehensively assessed before any revenue or loan guarantees are considered by project sponsors to support the project. This paper shows that the framework can be used even in the context of the intuitive binomial lattice model. This requires estimating volatility directly from the evolution of the net operating income while accounting for the correlation between the revenue and costs functions. This approach ensures that the uncertainties usually associated with toll revenues, in particular, are thoroughly investigated and their impact on project viability is thoroughly assessed. This paper illustrates the usefulness of the framework with data from an actual (BOT) toll road project. The results show that by postponing the project for a couple of years the project turns out to be viable, whereas it was not without the deferral. The evaluation approach proposed therefore provides a better framework for determining when and the extent of government financial support, if any, that may be needed to support a BOT project on the basis of project economics. The analysis may also be applicable to private sector investment projects, which are characterized by irreversibility and a high rate of uncertainty

    Invalid party wall awards and how to avoid them

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    Considers the reasons for the invalidity of party wall awards. Examines decided cases under earlier party wall legislation in the context of the Party Wall etc. Act 1996. Explains invalidity on the basis of an excess of the surveyors’ statutory authority. Defines this authority in terms of jurisdiction and power. Demonstrates the limits of the surveyors’ authority and emphasises the importance of strict compliance with statutory procedures. Concludes that surveyors should adopt an inquisitive and analytical approach to the scope of their authority to avoid the possibility of invalid awards. Echoes John Anstey’s earlier warning that surveyors should avoid a broad-brush approach to their duties which will only leave them “covered in soot”

    Vertical Field-Effect Transistor Based on Wavefunction Extension

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    We demonstrate a mechanism for a dual layer, vertical field-effect transistor, in which nearly-depleting one layer will extend its wavefunction to overlap the other layer and increase tunnel current. We characterize this effect in a specially designed GaAs/AlGaAs device, observing a tunnel current increase of two orders of magnitude at cryogenic temperatures, and we suggest extrapolations of the design to other material systems such as graphene

    The use of indigenous knowledge in development: problems and challenges

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    The use of indigenous knowledge has been seen by many as an alternative way of promoting development in poor rural communities in many parts of the world. By reviewing much of the recent work on indigenous knowledge, the paper suggests that a number of problems and tensions has resulted in indigenous knowledge not being as useful as hoped for or supposed. These include problems emanating from a focus on the (arte)factual; binary tensions between western science and indigenous knowledge systems; the problem of differentiation and power relations; the romanticization of indigenous knowledge; and the all too frequent decontextualization of indigenous knowledge
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