Using properties of the cdf of a random variable defined as a saddle-type point of a real valued continuous stochastic process, we derive first-order asymptotic properties of tests for stochastic spanning w.r.t. a stochastic dominance relation. First, we define the concept of Markowitz stochastic dominance spanning, and develop an analytical representation of the spanning property. Second, we construct a non-parametric test for spanning via the use of an empirical analogy. The method determines whether introducing new securities or relaxing investment constraints improves the invest- ment opportunity set of investors driven by Markowitz stochastic dominance. In an application to standard data sets of historical stock market returns, we reject mar- ket portfolio Markowitz efficiency as well as two-fund separation. Hence there exists evidence that equity management through base assets can outperform the market, for investors with Markowitz type preferences.
This study analyses first the impact of various income sources on overall income inequality in Switzerland in 1980, on the basis of the Income and Wealth Survey which was conducted during that year. The specific effect of each of these income sources is analyzed separately for male- and female-headed households and an attempt is made to also determine their role in explaining the difference between the level of overall income inequality in these two subpopulations. It appears that differences between the two groups in the shares of the various income sources play a greater role than differences in the within income sources inequality.
In this paper the transfer problem is analysed in a three country, three commodity (including one non-traded good) trade model where two countries belong to a customs union. The three countries A, B and C each produce three goods and engage in an asymmetric pattern of trade. Countries A and B form a customs union and C remains outside the union. Several results are obtained. Following the tradition in the literature on transfers and the terms of trade the results are classified into three groups: orthodox, anti-orthodox and mixed. In the orthodox case, donor (recipient) impoverishment (enrichment) occurs irrespective of the favourable (adverse) movement in the terms of trade. In the anti-orthodox case, donor (recipient) enrichment (impoverishment) occurs as a consequence of the favourable movement in the term of trade. In the mixed cases, the outcomes are not clearcut. The major result that we obtain is that changes in welfare, terms of trade and the relative price of the non-traded good are identical in the donor and the non-participating country as a consequence of the transfer. Thus an intra union transfer has effects on the non-participating country. Consider the orthodox case. Country B (donor) makes a transfer to country A (recipient), who are both in the union. Country B's welfare falls, terms of trade deteriorate and the relative price of the non-traded good falls. Country C, the non-participating country, suffers from the same effects. Structural adjustments occur in all the three countries — output of the non-traded good changes vis-a-vis the traded good and this change in composition is identical for the donor and the non-union country. In the anti-orthodox case both the donor and the non-participant country gain from the transfer. The non-union country cannot remain passive to transfers among the union members.
Understanding and reducing the incidence of accidental bycatch, particularly for vulnerable species such as sharks, is a major challenge for contemporary fisheries management worldwide. Bycatch data, most often collected by at-sea observers during fishing trips, are clustered by trip and/or vessel and typically involve a large number of zero counts and very few positive counts. Though hurdle models are very popular for count data with excess zeros, models for clustered forms have received far less attention. Here we present a novel random-effects hurdle model for bycatch data that makes available accurate estimates of bycatch probabilities as well as other clusterspecific targets. These are essential for informing conservation and management decisions as well as for identifying bycatch hotspots, often considered the first step in attempting to protect endangered marine species. We validate our methodology through simulation and use it to analyze bycatch data on critically endangered hammerhead sharks from the U.S. National Marine Fisheries Service Pelagic Observer Program.
