229 research outputs found
A total-evidence approach to dating with fossils, applied to the early radiation of the Hymenoptera
unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited
Fractal Profit Landscape of the Stock Market
We investigate the structure of the profit landscape obtained from the most
basic, fluctuation based, trading strategy applied for the daily stock price
data. The strategy is parameterized by only two variables, p and q. Stocks are
sold and bought if the log return is bigger than p and less than -q,
respectively. Repetition of this simple strategy for a long time gives the
profit defined in the underlying two-dimensional parameter space of p and q. It
is revealed that the local maxima in the profit landscape are spread in the
form of a fractal structure. The fractal structure implies that successful
strategies are not localized to any region of the profit landscape and are
neither spaced evenly throughout the profit landscape, which makes the
optimization notoriously hard and hypersensitive for partial or limited
information. The concrete implication of this property is demonstrated by
showing that optimization of one stock for future values or other stocks
renders worse profit than a strategy that ignores fluctuations, i.e., a
long-term buy-and-hold strategy.Comment: 12 pages, 4 figure
Financial Transaction Tax: Small is Beautiful
The case for taxing financial transactions merely to raise more revenues from the financial sector is not particularly strong. Better alternatives to tax the financial sector are likely to be available. However, a tax on financial transactions could be justified in order to limit socially
undesirable transactions when more direct means of doing so are unavailable for political or
practical reasons. Some financial transactions are indeed likely to do more harm than good,
especially when they contribute to the systemic risk of the financial system. However, such a
financial transaction tax should be very small, much smaller than the negative externalities in
question, because it is a blunt instrument that also drives out socially useful transactions.
There is a case for taxing over-the-counter derivative transactions at a somewhat higher rate
than exchange-based derivative transactions. More targeted remedies to drive out socially
undesirable transactions should be sought in parallel, which would allow, after their
implementation, to reduce or even phase out financialtransaction taxes
Österreichisches Projekt Grundlagen zur Züchtung, Vermehrung und Sorten-/Saatgutprüfung für den Biolandbau: Ergebnisübersicht
In the Austrian research project “Basic principles for breeding, multiplication and
variety testing for organic agriculture” (from 2004 until 2008) novel methods for the
assessment of the suitability of seed and cultivars for organic farming were developed
and evaluated by an interdisciplinary co-operation of researchers, breeders and
variety testers. Organic farming requires specific combinations of crop plant
characters, especially seed health and resistance against seed-borne diseases.
Another crucial feature is the competitive ability against weeds. Early development
was found to significantly increase the competitiveness of different crop plants.
Genotypic variation in characters necessary for an efficient utilisation of below-ground
resources was also investigated, e.g. interrelations between root development and
drought stress tolerance and between mycorrhiza formation and nutrient use
efficiency. Based on the results obtained in various cultivar trials, it can be concluded
that genotypes suitable for organic growing conditions may be pre-selected from early
breeding material of conventional breeding programmes. The selected breeding
material must subsequently be rigorously tested on organically managed fields starting
from the first yield trials at the latest. The project results were communicated to
farmers and advisors during field days and excursions. They will be applied in the
breeding of new cultivars
- …