Infinite sequence of fixed point free pseudo-Anosov homeomorphisms

We construct infinite sequences of pseudo-Anosov homeomorphisms without fixed points and leaving invariant a sequence of orientable measured foliations on the same topological surface and the same stratum of the space of abelian differentials. The existence of such sequences show that all pseudo-Anosov homeomorphisms fixing orientable measured foliations cannot be obtained by the Rauzy-Veech induction strategy

Volume entropy for surface groups via Bowen-Series like maps

We define a Bowen-Series like map for every geometric presentation of a co-compact surface group and we prove that the volume entropy of the presentation is the topological entropy of this particular (circle) map. Finally we find the minimal volume entropy among geometric presentations

Identification of strategic industries: a dynamic perspective

Reliable estimates of the economy-wide losses associated with closedown of an industry are generally hard to obtain. In the input-output literature, numerous measures of the social value of industries were proposed. These measures are mostly based on comparative statics results, whereas a dynamic perspective seems much more in demand. In this paper, "hypothetical extraction" methods are used in a new dynamic input-output model of economic growth. This model also stresses the importance of technological linkages between industries and of international trade performance. The potential power of the dynamic extraction methodology is illustrated by simulation results for a hypothetical economy.

Roots, symmetries and conjugacy of pseudo-Anosov mapping classes

An algorithm is proposed that solves two decision problems for pseudo-Anosov elements in the mapping class group of a surface with at least one marked fixed point. The first problem is the root problem: decide if the element is a power and in this case compute the roots. The second problem is the symmetry problem: decide if the element commutes with a finite order element and in this case compute this element. The structure theorem on which this algorithm is based provides also a new solution to the conjugacy problem

Why VAR Fails: Long Memory and Extreme Events in Financial Markets

The Value-at-Risk (VAR) measure is based on only the second moment of a rates of return distribution. It is an insufficient risk performance measure, since it ignores both the higher moments of the pricing distributions, like skewness and kurtosis, and all the fractional moments resulting from the long - term dependencies (long memory) of dynamic market pricing. Not coincidentally, the VaR methodology also devotes insufficient attention to the truly extreme financial events, i.e., those events that are catastrophic and that are clustering because of this long memory. Since the usual stationarity and i.i.d. assumptions of classical asset returns theory are not satisfied in reality, more attention should be paid to the measurement of the degree of dependence to determine the true risks to which any investment portfolio is exposed: the return distributions are time-varying and skewness and kurtosis occur and change over time. Conventional mean-variance diversification does not apply when the tails of the return distributions ate too fat, i.e., when many more than normal extreme events occur. Regrettably, also, Extreme Value Theory is empirically not valid, because it is based on the uncorroborated i.i.d. assumption.Long memory, Value at Risk, Extreme Value Theory, Portfolio Management, Degrees of Persistence

Straight from the horse’s mouth: children’s reception of dubbed animated films in Spain

Reception studies in the field of audiovisual translation (AVT) have increased considerably in the last two decades, including the target viewer in the picture. This paper presents the results of a study exploring young children’s reactions to some of the translation strategies regularly adopted in dubbed animated films. A total of 163 participants were shown nine animated film clips dubbed from English into Spanish, which included cultural references, colloquial language, educational content and songs. Data were then collected through a questionnaire adapted to the participants’ level of cognitive development and the analysis was based on two independent variables: the participants’ year in school and the number of previous viewings of the films. The results show that children do not seem to have much trouble understanding cultural, educational and musical content that is specific to the source culture and is kept in the target text. Interestingly, having previously watched the films does not appear to be a determining factor in children’s ability to identify these elements

Optimal Multi-Currency Investment Strategies with Exact Attribution in Three Asian Countries

Singer and Karnosky's (1995) exact and complete return attribution framework does not account for risk, since it ignores accumulated historical information. Its implied investment strategy selection is based on simple return maximization and ignores that investment strategies are correlated via intra-and inter-market risks. Using simple tensor algebra we extend their exact accounting framework to include market risk measurements for n countries. The resulting n^2 x n^2 strategy risk matrix exactly decomposes into a tensor sum of the n x n fundamental market risk matrices. Since the strategy risk matrix is singular with rank = 2n-1