The persistence of return on assets: differences between industries and differences between firms

This study offers a statistical analysis of the persistence of annual profits across a sample of firms from different European Union (EU) countries. To this end, a Bayesian dynamic model has been used which enables the annual behaviour of those profits to be broken down into a permanent structural component on the one hand and a transitory component on the other, while also distinguishing between general effects affecting the industry as a whole to which each firm belongs and specific effects affecting each firm in particular. This break down enables the relative importance of those fundamental components to be evaluated. The data analysed come from a sample of 23,293 firms in EU countries selected from the AMADEUS data-base. The period analysed ran from 1999 to 2007 and 21 sectors were analysed, chosen in such a way that there was a sufficiently large number of firms in each country*sector combination for the industry effects to be estimated accurately enough for meaningful comparisons to be made by sector and country. The analysis has been conducted by sector and by country from a Bayesian perspective, thus making the study more flexible and realistic since the estimates obtained do not depend on asymptotic results. In general terms, the study finds that, although the industry effects are significant, more important are the specific effects. That importance varies depending on the sector or the country in which the firm carries out its activity. The influence of firm effects accounts for more than 90% of total variation and display a significantly lower degree of persistence, with adjustment speeds oscillating around 51.1%. However, this pattern is not homogeneous but depends on the sector and country analysed. Industry effects have a more marginal importance, being significantly more persistent, with adjustment speeds oscillating around 10% with this degree of persistence being more homogeneous at both country and sector levels.

Estudio de la variabilidad de la esparceta de un corte cultivada en España

La esparceta es un tradicional cultivo forrajero de gran importancia en determinadas zonas del nordeste español a cuya mejora agronómica y genética se ha prestado poca atención. El presente trabajo analiza la variabilidad existente en los materiales cultivados en nuestro país del tipo común o de un corte y estudia la existencia de diferencias ecotípicas y su caracterización. Los resultados obtenidos ponen de manifiesto la gran variabilidad existente intra e interpoblacional, diferenciándose perfectamente las esparcetas de uno y dos cortes. La diferenciación dentro de cada uno de estos tipos no es tan clara. La zona más homogénea y mejor caracterizada es la de Teruel.

Cultures en contacte a Catalunya

En el actual escenario mundial, interconectado en el circuito de la mundialización cultural, con poblaciones cada vez más heterogéneas a causa de los desplazamientos internos y extracomunitarios, el contacto de civilizaciones provoca tensiones y efectos múltiples y conectados en cadena en el ámbito económico, social, político y cultural. En este sentido, la cuestión que centra los debates es la problemática resultante de la vida, en común o en paralelo, en un mismo territorio, de las culturas que historicamente están ya asentadas con las que van llegando, que son (muy) diferentes. En nuestro estado multinacional, Cataluña tiene unas condiciones óptimas para ser observada como un paradigma, porque forma parte de este circuito mundializado; porque es un punto de llegada de una parte importante de la actual inmigración comunitaria y extracomunitaria; porque, además, tiene ya como bagaje una experiencia, no tan lejana, de recepción de emigrantes culturalmente distantes, de la que se desprenden tendencias interesantes para orientar el presente y consolidar en el futuro el escenario multicultural que ya se empieza a vertebrar.

Clinical Utility of the 2 New Scales of the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA): A Naturalistic, Prospective Study in a Psychiatric Unit for Adolescents.

OBJECTIVES: The goal of this study was to assess the clinical usefulness of the emotional symptoms (Emo) and externalizing problems (Ext) scales compared with the Total score on the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA). METHODS: The HoNOSCA was rated at admission and discharge for 260 adolescent inpatients. The primary outcomes assessed were (a) the sensitivity of the 3 HoNOSCA scores to clinical improvement; and (b) the between diagnoses discriminative value of these scores. RESULTS: Analyses of variances [2 (time: admission vs. discharge) ×5 (diagnostic groups)] revealed a main effect of time for the 3 scores, a main effect of the diagnostic group for the Total and Ext scores, and an interaction effect between time and diagnosis for the Emo score. A moderate correlation was observed between the change in Ext and Emo scores between admission and discharge. DISCUSSION: These 2 new scales of the HoNOSCA demonstrated good clinical utility and the ability to assess different aspects of clinical improvements. A significant discriminative value of both scores was observed. SIGNIFICANT OUTCOMES: The clinical utility of the 2 new scales on the HoNOSCA was established. These 2 new scales provided a sensitive measure of clinical outcome for assessing improvement between admission and discharge on a psychiatric inpatient unit for adolescents, regardless of diagnostic group, and captured additional information about clinical improvements. Adolescents with psychosis and conduct disorders presented with higher externalizing symptoms than those with other disorders, as rated on the HoNOSCA, at admission and discharge. The Emo score differentiated between clinical improvement in patients with psychosis versus eating disorders. LIMITATIONS: The sample in this study represented a homogeneous population of adolescent inpatients, so that further research is needed before these findings can be generalized to outpatients. In addition, the small number of patients in some diagnostic groups did not allow for their inclusion in some of the statistical analyses.

Spontaneous Emergence of Chirality in the Limited Enantioselectivity Model: Autocatalytic Cycle Driven by an External Reagent

The emergence of chirality in enantioselective autocatalysis for compounds unable to transform according to the Frank-like reaction network is discussed with respect to the controversial limited enantioselectivity (LES) model composed of coupled enantioselective and non-enantioselective autocatalyses. The LES model cannot lead to spontaneous mirror symmetry breaking (SMSB) either in closed systems with a homogeneous temperature distribution or in closed systems with a stationary non-uniform temperature distribution. However, simulations of chemical kinetics in a two-compartment model demonstrate that SMSB may occur if both autocatalytic reactions are spatially separated at different temperatures in different compartments but coupled under the action of a continuous internal flow. In such conditions, the system can evolve, for certain reaction and system parameters, toward a chiral stationary state; that is, the system is able to reach a bifurcation point leading to SMSB. Numerical simulations in which reasonable chemical parameters have been used suggest that an adequate scenario for such a SMSB would be that of abyssal hydrothermal vents, by virtue of the typical temperature gradients found there and the role of inorganic solids mediating chemical reactions in an enzyme-like role.

Holographic isotropization linearized

The holographic isotropization of a highly anisotropic, homogeneous, strongly coupled, non-Abelian plasma was simplified in ref. [1] by linearizing Einstein"s equations around the final, equilibrium state. This approximation reproduces the expectation value of the boundary stress tensor with a 20% accuracy. Here we elaborate on these results and extend them to observables that are directly sensitive to the bulk interior, focusing for simplicity on the entropy production on the event horizon. We also consider next-to-leading-order corrections and show that the leading terms alone provide a better description of the isotropization process for the states that are furthest from equilibrium.

Decreasing fires in a Mediterranean region (1970-2010, NE Spain)

We analyse the recent evolution of fires in Catalonia (north-eastern Iberian Peninsula), a typical Mediterranean region. We examine a homogeneous series of forest fires in the period 1970-2010. During this period, more than 9000 fire events greater than 0.5 ha were recorded, and the total burned area was more than 400 kha. Our analysis shows that both the burned area and number of fire series display a decreasing trend. Superposed onto this general decrease, strong oscillations on shorter time scales are evident. After the large fires of 1986 and 1994, the increased effort in fire prevention and suppression could explain part of the decreasing trend. Although it is often stated that fires have increased in Mediterranean regions, the higher efficiency in fire detection could have led to spurious trends and misleading conclusions.

Provision of supplementary materials in Library and Information Science scholarly journals

Purpose- This study seeks to analyse the policies of library and information science (LIS) journals regarding the publication of supplementary materials, the number of journals and articles that include this feature, the kind of supplementary materials published with regard to their function in the article, the formats employed and the access provided to readers. Design/methodology/approach- The study analysed the instructions for authors of LIS journals indexed in the ISI Journal Citation Reports, as well as the supplementary materials attached to the articles published in their 2011 online volumes. Findings- Large publishers are more likely to have a policy regarding the publication of supplementary materials, and policies are usually homogeneous across all the journals of a given publisher. Most policies state the acceptance of supplementary materials, and even journals without a policy also publish supplementary materials. The majority of supplementary materials provided in LIS articles are extended methodological explanations and additional results in the form of textual information in PDF or Word files. Some toll-access journals provide open access to any reader to these files. Originality/value- This study provides new insights into the characteristics of supplementary materials in LIS journals. The results may be used by journal publishers to establish a policy on the publication of supplementary materials and, more broadly, to develop data sharing initiatives in academic settings.

Evolutionary Games in Networked Populations: Models and Experiments

Cooperation and coordination are desirable behaviors that are fundamental for the harmonious development of society. People need to rely on cooperation with other individuals in many aspects of everyday life, such as teamwork and economic exchange in anonymous markets. However, cooperation may easily fall prey to exploitation by selfish individuals who only care about short- term gain. For cooperation to evolve, specific conditions and mechanisms are required, such as kinship, direct and indirect reciprocity through repeated interactions, or external interventions such as punishment. In this dissertation we investigate the effect of the network structure of the population on the evolution of cooperation and coordination. We consider several kinds of static and dynamical network topologies, such as Baraba´si-Albert, social network models and spatial networks. We perform numerical simulations and laboratory experiments using the Prisoner's Dilemma and co- ordination games in order to contrast human behavior with theoretical results. We show by numerical simulations that even a moderate amount of random noise on the Baraba´si-Albert scale-free network links causes a significant loss of cooperation, to the point that cooperation almost vanishes altogether in the Prisoner's Dilemma when the noise rate is high enough. Moreover, when we consider fixed social-like networks we find that current models of social networks may allow cooperation to emerge and to be robust at least as much as in scale-free networks. In the framework of spatial networks, we investigate whether cooperation can evolve and be stable when agents move randomly or performing Le´vy flights in a continuous space. We also consider discrete space adopting purposeful mobility and binary birth-death process to dis- cover emergent cooperative patterns. The fundamental result is that cooperation may be enhanced when this migration is opportunistic or even when agents follow very simple heuristics. In the experimental laboratory, we investigate the issue of social coordination between indi- viduals located on networks of contacts. In contrast to simulations, we find that human players dynamics do not converge to the efficient outcome more often in a social-like network than in a random network. In another experiment, we study the behavior of people who play a pure co- ordination game in a spatial environment in which they can move around and when changing convention is costly. We find that each convention forms homogeneous clusters and is adopted by approximately half of the individuals. When we provide them with global information, i.e., the number of subjects currently adopting one of the conventions, global consensus is reached in most, but not all, cases. Our results allow us to extract the heuristics used by the participants and to build a numerical simulation model that agrees very well with the experiments. Our findings have important implications for policymakers intending to promote specific, desired behaviors in a mobile population. Furthermore, we carry out an experiment with human subjects playing the Prisoner's Dilemma game in a diluted grid where people are able to move around. In contrast to previous results on purposeful rewiring in relational networks, we find no noticeable effect of mobility in space on the level of cooperation. Clusters of cooperators form momentarily but in a few rounds they dissolve as cooperators at the boundaries stop tolerating being cheated upon. Our results highlight the difficulties that mobile agents have to establish a cooperative environment in a spatial setting without a device such as reputation or the possibility of retaliation. i.e. punishment. Finally, we test experimentally the evolution of cooperation in social networks taking into ac- count a setting where we allow people to make or break links at their will. In this work we give particular attention to whether information on an individual's actions is freely available to poten- tial partners or not. Studying the role of information is relevant as information on other people's actions is often not available for free: a recruiting firm may need to call a job candidate's refer- ences, a bank may need to find out about the credit history of a new client, etc. We find that people cooperate almost fully when information on their actions is freely available to their potential part- ners. Cooperation is less likely, however, if people have to pay about half of what they gain from cooperating with a cooperator. Cooperation declines even further if people have to pay a cost that is almost equivalent to the gain from cooperating with a cooperator. Thus, costly information on potential neighbors' actions can undermine the incentive to cooperate in dynamical networks.

Hiomon AI-järjestelmän toimivuuden arviointi

Työn tavoitteena oli uudentyyppisen hiontaprosessin ohjausjärjestelmän kehittäminen ja testaaminen UPM-Kymmene Kaukaan hiomossa. Uuden ohjausjärjestelmän perusajatuksena oli pitää yksittäistä hiomakiveä jatkuvasti optimaalisessa toimintapisteessä, ja hiomon kaikilla koneilla pyrittiin samaan kivenalusmassan laatuun. Uutta ohjaustapaa kutsuttiin Optimum operating point -strategiaksi (OOPS). Hiomakiven pitäminen optimaalisessa toimintapisteessä tapahtui pääosin vesiteräyskäsittelyllä, jonka intensiteettiä ohjasi asiantuntijajärjestelmä (AI-järjestelmä). Lisäksi testattiin ohjelmoidun anturan nopeussäädön vaikutusta hiomakoneen resurssien käyttöön. AI-järjestelmä päätteli vesiteräyskäsittelyn tarpeellisuuden CSF-mallin ja hiomakoneen resurssien perusteella. Seurannasta saatujen tulosten perusteella AI-järjestelmän käyttöönotto vesiteräyskäsittelyssä paransi tuotannon ja massan laadun tasaisuutta. Hiomakoneiden resurssien havaittiin pienenevän puunsyöttölinjan mukaisesti. Paksummat pöllit kerääntyvät linjan päähän, jolloin varsinkin hydrauliikkapaineiden tarve lisääntyy linjan päässä olevilla hiomakoneilla. Hiomakoneen resurssit saatiin paremmin käyttöön kuormittamalla konetta ohjelmoidulla anturan nopeussäädöllä (ONS) kuin vakioidulla anturan nopeussäädöllä (VNS). Kuitenkin hydraulipaineresurssien puutteellisuus rajoitti koeajon aikana ONS:n toimintaa. Resursseja ei optimoitu koeajon aikana, koska kiven pinnan haluttiin pysyvän mahdollisimman stabiilina. Kivelle ei suoritettu mekaanista käsittelyä, vaikka kivenpinnan massan kuljetuskapasiteetin havaittiin olevan huono. AI-järjestelmä otettiin ohjaamaan vesiteräyskäsittelyä vasta ONS - VNS -koeajon jälkeen. Mekaanisen rullateräyksen jälkeen massan ominaisuudet muuttuivat, koska kiven pinnan terävät särmät katkoivat kuituja alentaen massan sitoutumiskykyä. Heti rullakäsittelyn jälkeen mitattu CSF saattoi jopa alentua huomattavasti, mutta AI-järjestelmän laskema CSF nousi selvästi indikoiden energian ominaiskulutuksen (EOK) laskua. Muutaman päivän hionnan jälkeen mitattu ja laskettu CSF saavuttivat saman tason.

Self-Organising Maps and Correlation Analysis as a Tool to Explore Patterns in Excitation-Emission Matrix Data Sets and to Discriminate Dissolved Organic Matter Fluorescence Components

Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

Biotechnology applied to Annona species: a review

Annonaceae is an ancient family of plants including approximately 50 genera growing worldwide in a quite restricted area with specific agroclimatic requirements. Only few species of this family has been cultivated and exploited commercially and most of them belonging to the genus Annona such as A. muricata, A. squamosa, the hybrid A. cherimola x A. squamosa and specially Annona cherimola: the cherimoya, commercially cultivated in Spain, Chile, California, Florida, México, Australia, Ecuador, Peru, Brazil, New Zealand and several countries in South and Central America. The cherimoya shows a high degree of heterozygosis, and to obtain homogeneous and productive orchards it is necessary to avoid the propagation by seeds of this species. Additionally, the traditional methods of vegetative propagation were inefficient and inadequate, due to the low morphogenetic potential of this species, and the low rooting rate. The in vitro tissue culture methods of micropropagation can be applied successfully to cherimoya and other Annona sp to overcome these problems. Most of the protocols of micropropagation and regeneration were developed using the cultivar Fino de Jete, which is the major cultivar in Spain. First it is developed the method to micropropagate the juvenile material of cherimoya (ENCINA et al., 1994), and later it was optimized a protocol to micropropagate adult cherimoya genotypes selected by outstanding agronomical traits (PADILLA and ENCINA, 2004) and further it was improved the process through micrografting (PADILLA and ENCINA, 2011).At the present time we are involved in inducing and obtaining new elite genotypes, as part of a breeding program for the cherimoya and other Annonas, using and optimizing different methodologies in vitro: a) Adventitious organogenesis and regeneration from cellular cultures (ENCINA, 2004), b) Ploidy manipulation of the cherimoya, to obtain haploid, tetraploid and triploid plants (seedless), c) Genetic transformation, for the genes introduction to control the postharvest processes and the genes introduction to provide resistance to pathogen and insects and d) Micropropagation and regeneration of other wild Annona or related Annonaceae species such as: Annona senegalensis, A. scleroderma, A. montana, A. reticulata, A. glabra, A. diversifolia and Rollinia sp.

Kernel-PCA data integration with enhanced interpretability

Background Nowadays, combining the different sources of information to improve the biological knowledge available is a challenge in bioinformatics. One of the most powerful methods for integrating heterogeneous data types are kernel-based methods. Kernel-based data integration approaches consist of two basic steps: firstly the right kernel is chosen for each data set; secondly the kernels from the different data sources are combined to give a complete representation of the available data for a given statistical task. Results We analyze the integration of data from several sources of information using kernel PCA, from the point of view of reducing dimensionality. Moreover, we improve the interpretability of kernel PCA by adding to the plot the representation of the input variables that belong to any dataset. In particular, for each input variable or linear combination of input variables, we can represent the direction of maximum growth locally, which allows us to identify those samples with higher/lower values of the variables analyzed. Conclusions The integration of different datasets and the simultaneous representation of samples and variables together give us a better understanding of biological knowledge.

Nuevas series anuales de población de América Latina desde el siglo XIX hasta el 2000

El estudio de la población en América Latina es un tema central en la historiografía de la región, sin embargo, las distintas estimaciones existentes muestran importantes discrepancias para los siglos XIX y XX. A partir del contraste de distintas bases de datos, la principal contribución del artículo consiste en ofrecer nuevas series de población homogéneas para el conjunto de países de América Latina, junto a una detallada explicación de la obtención de los datos, así como un análisis de las discrepancias que las distintas fuentes muestran. Los países que aborda este trabajo son Argentina, Brasil, Bolivia, Chile, Colombia, Costa Rica, Cuba, Guatemala, Ecuador, Haití, Honduras, México, Nicaragua, Panamá, Paraguay, Perú, República Dominicana, Uruguay y Venezuela; a lo que se agrega la suma de todos ellos para obtener la población latinoamericana. Estas nuevas series pueden resultar de gran utilidad para reinterpretar la historia económica de América Latina en el largo plazo. The analysis of population levels in Latin America plays an important role in the regional historiography. The estimated series appeared until now offers huge discrepancies, therefore, we believe essential to provide homogeneous series for the 19th and the 20th centuries. In our work we shed new light on this issue, from an exhaustive study of the existing Latin American historical sources for the region. Along with a detailed explanation of the data collection, we also provide an analysis of the discrepancies and the accuracy of sources. The study offers data from 21 countries in Latin America: Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, Cuba, Guatemala, Ecuador, Haiti, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Dominican Republic, Uruguay and Venezuela. This new evidence can be a crucial information to revisit Latin American Economic History in the long run.

On cumulant techniques in speech processing

This paper analyzes applications of cumulant analysis in speech processing. A special focus is made on different second-order statistics. A dominant role is played by an integral representation for cumulants by means of integrals involving cyclic products of kernels.