Results of a botanical expedition to Mount Roraima, Guyana : 2., Lichens

Lichen exploration of the Upper Mazaruni District, Guyana yielded 273 species, of which 179 were found for the first time in the Guianas and 13 were as yet undescribed. A list of all taxa encountered is presented, with indications of habitat and distribution in the investigated area as well as first descriptions for the following 7 species: Buellia aptrootii, Byssoloma farkasii, Myriotrema guianense, M. neofrondosum, M. subdactyliferum, Ocellularia astrolucens, and Thelotrema albomaculatum. Mazosia bambusae is recorded for the first time from the Neotropics. The richest areas for lichens appear to be the rocky tablelands with scrub vegetation on top of the lower mountains. The slopes of Mount Roraima are of special interest because they support some montane species which are unlikely to be found elsewhere in the Guianas; otherwise they are less rich in lichens, probably because of the high humidity, which favours bryophyte growth

A General MSSM Parameter Scan

The excluded tan(beta) range and Higgs boson mass regions in the framework of the Minimal Supersymmetric extension of the Standard Model (MSSM) depend on several parameters. The Higgs boson masses, cross-sections and branching fractions have been determined including two-loop diagrammatic calculations. The limits obtained with a more general scan over the parameter space of the MSSM are compared with those in the so-called benchmark scenario. The combination of the searches for Higgs particles in the 1999 data collected by the DELPHI collaboration at center-of-mass energies between 191.6 and 201.7 GeV allows stringent limits to be set in combination with previous DELPHI results. In addition, an interpretation in the framework of the general MSSM scan of the 2000 LEP data at the hightest energies between 201.7 and 209.0 GeV is given. We show that the current data for the HZ and hA production can be comfortably accommodated in the MSSM.Comment: 3 pages, 3 figure

Robust Stylized Facts on Comovement for the Spanish Economy

In this article we further develop the suggestion of obtaining stylized facts on comovement on the basis of prewhitened time series proposed in André, Pérez and Martín (2002). Firstly, we show some examples on the robustness of the method. Secondly, we test the relevance of such a proposal by revisiting some of the existing stylized facts on comovement for the Spanish economy in Dolado, Sebastián and Vallés (1993).Stylized Facts, Comovement, Cross Correlation Function, HP-Filter, Prewhitening

The Gini Coefficient Reveals More

We revisit the well-known decomposition of the Gini coefficient into betweengroups, within-groups and overlap terms in the context of two groups in which the incomes in one group may be scaled and that group’s population weight modified. In this more general setting than usual, we focus on the properties of the overlap term, proving inter alia that overlap unambiguously reduces as a result of a within-group progressive transfer, and is increased by scaling up the incomes in the group with the lower mean, reaching a maximum when the two means become the same. In the case of a socially heterogeneous population and equivalized incomes, the effect on the Gini overlap of changing the income unit is determined, along with that of adjusting the equivalence scale deflator in case the income unit is the equivalent adult (such adjustment simultaneously changing the weighting of income units).

OPTIMAL SUBSTITUTION OF RENEWABLE AND NONRENEWABLE NATURAL RESOURCES IN PRODUCTION

A theoretical model is presented in order to study the optimal combination of natural resources, used as inputs, taking into account their natural growth ability and the technical possibilities of input substitution. The model enables us to consider renewable resources, nonrenewable, or both. The relative use of resources evolves through time according to the difference between both resources' natural growth and technological flexibility, as measured by the elasticity of substitution of the production function. Output evolves according to a version of the traditional Keynes-Ramsey rule, where the marginal productivity of capital is substituted by the ''marginal productivity of natural capital'', that is a combination of both resources' marginal growth weighted by each resource return in production.Renewable Resources, Nonrenewable Resources, Production, Optimal Control.