Is the predictability of emerging and developed stock markets really exploitable?.

A number of recent papers have analyzed the degree of predictability of stock markets. In this paper, we firstly study whether this predictability is really exploitable and secondly, if the economic significance of predictability is higher or lower in the emerging stock markets than in the developed ones. We use a variety of linear and nonlinear – Artificial Neural Networks – models and perform a computationally demanding forecasting experiment to assess the predictability of returns. Since we are interested in comparing the predictability in economic terms we also propose a modification in the nets’ loss function for market trading purposes. In addition, we consider both explicit and implicit trading costs for emerging and developed stock markets. Our conclusions suggest that, in contrast to some previous studies, if we consider total trading costs both the emerging as well as the developed stock returns are clearly nonpredictable. Finally, we find that Artificial Neural Networks do not provide superior performance than the linear models.Finance; Forecasting; Emerging stock markets; Artificial neural networks;

Risk forecasting models and optimal portfolio selection.

This study analyses, from an investor's perspective, the performance of several risk forecasting models in obtaining optimal portfolios. The plausibility of the homoscedastic hypothesis implied in the classical Markowitz model is dicussed and more general models which take into account assymetry and time varying risk are analysed. Specifically, it studies whether ARCH-type based models obtain portfolios whose risk-adjusted returns exceed those of the classical Markowitz model. The same analysis is performed with models based on the Lower Partial Moment (LPM) which take into account the assymetry in the distribution of returns. The results suggest that none of the models achieve a clearly superior average performance. It is also found that models based on semivariance perform as well as those based on the variance, but not better than, even if the evaluation criterion is based on the Reward-to-Semivariance ratio. When attention turns to the analysis of worst case performance, the results are clearly different. Models which employ LPM with a high degree of risk aversion (n>2) as the risk measure are consistently superior to those which employ a symmetric measure, either homoscedastic or heteroscedastic.

Self-organizing maps could improve the classification of Spanish mutual funds.

In this paper, we apply nonlinear techniques (Self-Organizing Maps, k-nearest neighbors and the k-means algorithm) to evaluate the official Spanish mutual funds classification. The methodology that we propose allows us to identify which mutual funds are misclassified in the sense that they have historical performances which do not conform to the investment objectives established in their official category. According to this, we conclude that, on average, over 40% of mutual funds could be misclassified. Then, we propose an alternative classification, based on a double-step methodology, and we find that it achieves a significantly lower rate of misclassifications. The portfolios obtained from this alternative classification also attain better performances in terms of return/risk and include a smaller number of assets.Finance; Mutual funds; Clustering; Self-organizing map (SOM); Investment analysis;

The Wine Attributes with the Greatest Influence in the Process of Consumer Choice in Spain

The commercialisation of wine in Spain is problematic due to two concrete circumstances: the decrease in wine consumption because of a consumer shift toward substitute drinks and the greater presence of national and foreign wine in the interior market, which involves an increase in business competitiveness. The increase in competitiveness of quality Spanish wine depends on producing enterprises’ knowledge of wine consumer preferences so they can offer consumers what they demand. In order to respond to this matter and better adapt supply, 421 wine consumers were surveyed using the Best-Worst Scaling methodology. Various segmentations were also made by consumer income and age groups. The results indicate that the two main attributes which condition consumers in choosing wine are the region of origin and having tasted it previously. The region of origin attribute is valued in general by consumers over 34 years old who have a monthly family income above 1,500 €. The attribute of having tasted it before, which on many occasions is associated with the price attribute, is valued particularly by younger consumers and those with lower incomes.Consumer behaviour, Wine attributes, Food Marketing, Consumer/Household Economics,

A Multi-Level Analysis of World Scientific Output in Pharmacology

The purpose of this chapter is to analyse international research in “pharmacology, toxicology and pharmaceutics” (hereafter pharmacology) on the basis of the scientific papers listed in the Scopus multidisciplinary database. This primary objective is reached by answering the following questions (in the section on results). What weight does the subject area “pharmacology, toxicology and pharmaceutics” carry in world-wide science? What is the percentage contribution made by the various regions of the world to the subject area “pharmacology, toxicology and pharmaceutics”? Can certain regions be identified as leaders on that basis, as in other scientific contexts? Are emerging countries present in the field? Do the most productive countries also publish the largest number of journals? What features characterise the scientific output of companies that publish pharmacological papers

Non Equilibrium Physics of Single-Cell Genomics

The self-organisation of cells into complex tissues relies on the tight regulation of molecular processes governing their behaviour. Understanding these processes is a central questions in cell biology. In recent years, technological breakthroughs in single-cell sequencing experiments have enabled us to probe these processes with unprecedented molecular detail. However, biological function relies on collective processes on the mesoscopic and macroscopic scale, which do not necessarily obey the rules that govern it on the microscopic scale. Insights from these experiments on how collective processes determine cellular behaviour consequently remain severely limited. Methods from nonequilibrium statistical physics provide a rigorous framework to connect microscopic measurements to their mesoscopic or macroscopic consequences. In this thesis, by combining for the first time the possibilities of single-cell technologies and tools from nonequilbrium statistical physics, we develop theoretical frameworks that overcome these conceptual limitations. In particular, we derive a theory that maps measurements along the linear sequence of the DNA to mesoscopic processes in space and time in the cell nucleus. We demonstrate this approach in the context of the establishment of chemical modifications of the DNA (DNA methylation) during early embryonic development. Drawing on sequencing experiments both in vitro and in vivo, we find that the embryonic DNA methylome is established through the interplay between DNA methylation and 30-40 nm dynamic chromatin condensates. This interplay gives rise to hallmark scaling behaviour with an exponent of 5/2 in the time evolution of embryonic DNA methylation and time dependent, scale-free connected correlation functions, both of which are predicted by our theory. Using this theory, we successfully identify regions of the DNA that carry DNA methylation patterns anticipating cellular symmetry breaking in vivo. The primary layer determining cell identity is gene expression. However, read-outs of gene-expression profiling experiments are dominated by systematic technical noise and they do not provide “stochiometric” measurements that allow experimental data to be predicted by theories. Here, by developing effective spin glass methods, we show that the macroscopic propagation of fluctuations in the concentration of mRNA molecules gives direct information on the physical mechanisms governing cell states, independent of technical bias. We find that gene expression fluctuations may exhibit glassy behaviour such that they are long-lived and carry biological information. We demonstrate the biological relevance of glassy fluctuations by analysing single-cell RNA sequencing experiments of mouse neurogenesis. Taken together, we overcome important conceptual limitations of emerging technologies in biology and pioneer the application of methods from stochastic processes, spin glasses, field and renormalization group theories to single-cell genomics

DETERMINATION OF THE SURCHARGE THAT CONSUMERS ARE WILLING TO PAY FOR AN ORGANIC CHEESE IN SPAIN

Consumer requirements for preferably new, quality products with health guarantees are causing competitive adaptation by agro-food businesses. In this sense, cheese-producing enterprises are immersed in restructuring to adapt to the new scene. To assure the greatest possible success in this process it is advisable to determine what the preferences of cheese consumers are. In searching for the answer to this question, 420 surveys were made on regular food shoppers for at-home consumption in the metropolitan area of Madrid (Spain). Treatment of this data consisted in using the Conjoint Analysis technique and maximum willingness to pay. Results show that the main differentiating element for cheese is origin and the maximum willing to pay for an organic cheese with respect a conventional one is 15.42%.Consumer behaviour, Organic, Food Marketing, Demand and Price Analysis,

Del hipertexto al hipermercado

Reflexión en torno al concepto de hipertexto, centrándose en los aspectos de autoría, lectura y definición. Se sostiene que los hipertextos no pueden estudiarse sólo desde la perspectiva textual sino que también como otra forma más de representación icónica. Se reflexiona, por último, sobre la naturaleza de una sociedad organizada en base a la simulación y la generación de mundos ilusorios. Este artículo está construido mediante relaciones isotópicas de diferentes citas. Todos los personajes y situaciones o diálogos que aparecen mencionados en el artículo son «ficticios». La «autoría» del texto debe ser juzgada por el lector, en consecuencia, por el juicio que le merezca la relevancia de las inserciones.This article reflects on the concept of bypertext, focusing primarily on authorship, reading and definition. It argües that hypertext can be studied not only from a textual perspective, but also as a form of iconic representation. Finally, it considers the nature of a society organized according to simulation and the creation of unreal worlds. This article has been constructed by isotopic relations of different quotations. Every character and situation or dialogue that is mentioned in this article is «fictitious». Who has been the author of the text is something that the reader should decide.Publicad