Compative robustness of six tests in repeated measures designs with specified departures from sphericity

In this article we examine the behaviour of six univariate statistics for analyzing the data of a Split-plot factorial design. Except for the univariate analysis of variance, which assumes that the dispersion matrix underlying the data is spherical, the other five procedures assume absence of sphericity. However, they do so with a clear distinction between two alternatives, insofar as three of them presuppose an arbitrary correlation between the data and two presuppose serial autocorrelation. These six approaches were compared with regard to their robustness under multivariate normality in the absence of sphericity, both when there was serial autocorrelation and when there was underlying arbitrary correlation. In general, Monte Carlo comparisons show that when underlying the data there is a autoregressive stationary or decreasing structured non-stationary autoregressive process, the Hearne, Clark and Hatch procedure is the most robust. In the rest of the conditions studied, i.e., increasing structured non-stationarity autoregressive and arbitrary non-stationarity (autoregressive and with arbitrary correlation), the Greenhouse-Geisser and Lecoutre statistics display the best behaviour.     

The internationalisation of SMEs from China: The case of Ningxia Hui Autonomous Region

This paper aims to study the international expansion of small and medium-sized enterprises (SMEs) in an emerging economy. Mathews’ (2006: 5–27) linkage–leverage–learning (LLL) model is the framework applied to analyse the process of international expansion of SMEs. To operationalise the study of the barriers, the LLL model was linked to the work of Leonidou (2004: 279–302). The data was collected from 125 SMEs operating in Ningxia, China, and then analysed using multivariate regressions; the models used the firms’ export intensity at the regional, national and international level as dependent variables. Four models were run: two analysing the internal and external barriers hindering firms’ international expansion, and the other two models studying the characteristics of Chinese international companies (state funding and ownership) as independent variables. The results show that 12 of the barriers defined by Leonidou (2004) are hindering the expansion of Ningxia’s SMEs, that the ownership from the state does not play an important role in this expansion, and that the support from the state in the form of funds is helpful in the first stages of the expansion (regional level) and the funds from private sources are key to cross the country’s boundaries.     

Latin American retail: where modernity blends with tradition

Latin America's retail landscape has changed dramatically over the last 20 years. Attracted by deregulation and a sizable and growing market, modern retailers arrived looking for the next El Dorado. But signs of maturity appeared much before expected. Traditional retailers modernized their offer, while keeping their appeal to the emerging consumers. While chain retail has concentrated earlier than expected – and faster by the hand of crisis that are usual in emerging markets –, local chains have developed formats which add modernity to their understanding of their customers' base. By providing better access through convenience and credit to a broader range that even includes affordable design and quality, local chains are showing the way to the growing mass customers that form Latin America's new emerging middle class. And leveraging on this customer understanding, they are redefining concepts like convenience and crossing borders to grab the opportunity of the new emerging consumers. This article covers the evolution of retailing in Latin America over the past two decades, and provides insights on the segment that has brought the most significant growth: emerging consumers.     

Information Gathering and Marketing

Consumers have only partial knowledge before making a purchase decision, but can acquire more‐detailed information. Marketing makes it easier or harder for these consumers to do so. When consumers are ex ante heterogeneous, the firm might choose an intermediate marketing strategy for two quite different reasons. First, as a nonprice means of discrimination—it can make information only partially available, in a way that induces some, but not all, consumers to acquire the information. Second, when the firm cannot commit to a given investment in ensuring quality, the marketing and pricing strategy can act as a commitment device.     

Dynamic Volume-Return Relation of Individual Stocks

We examine the dynamic relation between return and volume ofindividual stocks. Using a simple model in which investors tradeto share risk or speculate on private information, we show thatreturns generated by risk-sharing trades tend to reverse themselves,while returns generated by speculative trades tend to continuethemselves. We test this theoretical prediction by analyzingthe relation between daily volume and first-order return autocorrelationfor individual stocks listed on the NYSE and AMEX. We find thatthe cross-sectional variation in the relation between volumeand return autocorrelation is related to the extent of informedtrading in a manner consistent with the theoretical prediction.     

Relative price volatility under Sudden Stops: The relevance of balance sheet effects

Sudden Stops are associated with increased volatility in relative prices. We introduce a model based on information acquisition to rationalize this increased volatility. An empirical analysis of the conditional variance of the wholesale price to consumer price ratio using panel ARCH techniques confirms the relevance of Sudden Stops and potential balance sheet effects as key determinants of relative price volatility, where balance sheet effects are captured by the interaction of a proxy for potential changes in the real exchange rate (linked to the degree of external leverage of the absorption of tradable goods) and a measure of domestic liability dollarization.     

The multilinear extension and the coalition structure value

The multilinear extension has been shown to be an effective tool for computing the Shapley value of an n-person game. We modify here the method for the multilinear extension to calculate the modified coalition structure value (CS-value) for such games.     

Dynamic Use of Closures and Imperfectly Enforced Quotas in a Metapopulation

The dynamic efficiency of closures in bioeconomic systems depends upon stock levels and in situ values that evolve over time, and on relative costs of implementation. A model of a harvested metapopulation is presented in which second-best reduction of harvest from open-access levels using input quotas balances monitoring costs against dynamic benefits of mitigating overharvesting. Temporary or permanent closures—though generally still second best—are preferable to quotas under certain conditions, as demonstrated for a representative patch and time period. Interactions between patches are discussed. Numerical solutions illustrate comparative dynamics of closure use, and show their potential benefits in a dynamic regulatory path.     

Does Conservation Agriculture Change Labour Requirements? Evidence of Sustainable Intensification in Sub-Saharan Africa

Population growth, increasing wealth and changing diets require agriculture in Sub-Saharan Africa to intensify to meet future food demand and ensure food security in the region. Conservation agriculture can increase yields in the long run and reduce the negative environmental impacts of intensive farming. In changing the mix of resources used and how they are managed, the adoption of conservation agriculture can have a direct impact on farm labour. We study the relationship between conservation agriculture and labour input requirements as observed in five Sub-Saharan African countries. We focus on the amount of work required and the source of the work employed (household or hired, by gender, by children and by production stage). We apply multinomial endogenous switching regression models on a panel of household and farm data from Ethiopia, Kenya, Malawi, Mozambique and Tanzania. We find that conservation agriculture increases farms’ labour input requirements. Higher demand is driven by more work during the harvesting and threshing stages. Increases in labour requirements are usually met by household labour, not paid work. The workload change is also higher for women than for men, and, in certain cases, is met by children.     

Bio-economic modelling of soil erosion externalities and policy options: a Tunisian case study

Soil erosion is one of the most important of today’s environmental externalities and a major threat to sustainability of agricultural system. It constitutes the most widespread forms of land degradation throughout the world. The aim of this paper is to estimate the amount of soil erosion generated by the current cropping systems in Tunisia and to assess the economic and ecological impacts of policy instruments designed to handle this problem. The analysed policy options are based on soil conservation practices and direct incentive farming anti-erosive measures. The selected measures are the reduction of tillage, the avoidance of bare fallow and the use of legume-based crop rotation. A bio-economic modelling framework coupling the biophysical model EPIC to a non-linear dynamic programming farm model was used for this impact analysis. It was performed in a set of representative farms belonging to a region in North-Eastern Tunisia (Zaghouan) strongly affected by this phenomenon. The main finding of this research is the non-convexity of the crop yield—soil erosion space. That is, the use of more intensive techniques to increase productivity (i.e. crop yield) may be accompanied by rough changes in soil erosion (damage) curves, manifested either by non-monotony or non-convexity. In term of policy options and because of giving up convexity assumptions, incentive anti-erosive measures appear more efficient than conventional environmental policies such as Pigouvian taxes or quota systems. The implementation of soil conservation practices would leads to a net decrease in soil erosion and an increase in farm income. However, with the current interest rate of 7% the possible rise in income is not enough to stimulate farmers to invest on these practices. A maximum rate of 4% would be necessary to make this policy option more effective.