Reliable detection of directional couplings using rank statistics

To detect directional couplings from time series various measures based on distances in reconstructed state spaces were introduced. These measures can, however, be biased by asymmetries in the dynamics' structure, noise color, or noise level, which are ubiquitous in experimental signals. Using theoretical reasoning and results from model systems we identify the various sources of bias and show that most of them can be eliminated by an appropriate normalization. We furthermore diminish the remaining biases by introducing a measure based on ranks of distances. This rank-based measure outperforms existing distance-based measures concerning both sensitivity and specificity for directional couplings. Therefore, our findings are relevant for a reliable detection of directional couplings from experimental signals.

Ownership structure and innovation: Is there a real link?

This work focuses on the study of the relationship between ownership and control structure of the company and its innovative activity. Its aim consists of analysing the role that may be played by determinants within the company related to ownership structure when the decision to incur research and development activities is taken as well as on the output of this innovate process. Among these determinants we may think of issues such as who owns the firm and how the control of decision-making is distributed, the nature of this control and the level of concentration of ownership, among others. The study is carried out for the year 2001 using a representative sample of Spanish manufacturing industries.

Evidence on the complex link between

Most studies analysing the infrastructure impact on regional growth show a positive relationship between both variables. However, the public capital elasticity estimated in a Cobb-Douglas function, which is the most common specification in these works, is sometimes too big to be credible, so that the results have been partially desestimated. In the present paper, we give some new advances on the real link between public capital and productivity for the Spanish regions in the period 1964-1991. Firstly, we find out that the association for both variables is smaller when controlling for regional effects, being industry the sector which reaps the most benefits from an increase in the infrastructural dotation. Secondly, concerning to the rigidity of the Cobb-Douglas function, it is surpassed by using the variable expansion method. The expanded functional form reveals both the absence of a direct effect of infrastructure and the fact that the link between infrastructure and growth depends on the level of the existing stock (threshold level) and the way infrastructure is articulated in its location relative to other factors. Finally, we analyse the importance of the spatial dimension in infrastructure impact, due to spillover effects. In this sense, the paper provides evidence of the existence of spatial autocorrelation processes that may invalidate previous results.

Evidence on the complex link between

Most studies analysing the infrastructure impact on regional growth show a positive relationship between both variables. However, the public capital elasticity estimated in a Cobb-Douglas function, which is the most common specification in these works, is sometimes too big to be credible, so that the results have been partially desestimated. In the present paper, we give some new advances on the real link between public capital and productivity for the Spanish regions in the period 1964-1991. Firstly, we find out that the association for both variables is smaller when controlling for regional effects, being industry the sector which reaps the most benefits from an increase in the infrastructural dotation. Secondly, concerning to the rigidity of the Cobb-Douglas function, it is surpassed by using the variable expansion method. The expanded functional form reveals both the absence of a direct effect of infrastructure and the fact that the link between infrastructure and growth depends on the level of the existing stock (threshold level) and the way infrastructure is articulated in its location relative to other factors. Finally, we analyse the importance of the spatial dimension in infrastructure impact, due to spillover effects. In this sense, the paper provides evidence of the existence of spatial autocorrelation processes that may invalidate previous results.

Ownership structure and innovation: Is there a real link?

This work focuses on the study of the relationship between ownership and control structure of the company and its innovative activity. Its aim consists of analysing the role that may be played by determinants within the company related to ownership structure when the decision to incur research and development activities is taken as well as on the output of this innovate process. Among these determinants we may think of issues such as who owns the firm and how the control of decision-making is distributed, the nature of this control and the level of concentration of ownership, among others. The study is carried out for the year 2001 using a representative sample of Spanish manufacturing industries.

Cela Espín, X. i Revilla Calvo, V., Annexos de Jaume Buxeda i Garrigós i Miquel Ângel Cau Ontiveros; Mariana Pérez-Sala i Rodés; Eva Orri Terrado i Alicia Estrada Martín.: La transició del municipium d'Iluro a Alarona (Mataró). Cultura material i transformacions d"un espai urbà entre els segles V i VII dC. Laietania, 15, 2004

Aquest llibre reuneix un estudi arqueològic extraordinàriament acurat referit a tot un seguit d'actuacions detectades a partir del registre arqueològic, que caracteritzen l'espai urbà de l'antiga Iluro durant el període de l'Antiguitat tardana. S'hi estudia amb molt deteniment cadascuna de les accions detectades -així com tot el mobiliari ceràmic relacionat- amb la finalitat de situar-les correctament en el temps, però també per entendre, a través de la cultura material, la dinàmica que pren la ciutat a les darreries de l'Antiguitat; per a poder intuir, més que saber, quina societat es desenvolupa darrere d¿aquests contenidors plens de productes alimentaris arribats d¿un ultramar llunyà i alhora molt proper; una societat capaç de respondre a l¿estímul exterior amb una producció pròpia que competirà o substituirà una gran part de la que ve de fora.

Euphorbia L. subsect. Esula (Boiss. in DC.) Pax in the Iberian Peninsula. Leaf surface, chromosome numbers and taxonomic treatment

Presentem l'estudi taxonòmic dels représentants d'Euphorbia subsect. Esula a la Península Ibèrica. Prèviament, s'inclou un primer capítol dedicai a l'estudi de les epidermis foliars i un segon capítol sobre nombres cromosòmics...

A proposito de los generos Aconitum L. y Consolida (DC.) S.F.Gray en la Peninsula Iberica.

Seguimos para este taxon, en lo nomenclatural, a TAMURA & LAUENER (1979:459), mientras no se tipifique de forma adecuada A. lycoctonum L., considerado nom. ambig. ya por TUTIN (1964:212), con pocas posibilidades de que no sea diverso de A. vulparia. A. pyrenaicum L. es también algo muy distinto del taxon que nos ocupa y, en caso de no ser aceptada la proposición de que se lo considere ñamen rejiciendum, hecha por TAMURA & LAUENER (Le.: 447), seria el nombre correcto para A. barbatum Pers. (=A. squarrosum DC.) de Siberia. Otro nombre que aún podría ser prioritario, A. altissimum Miller (WARNCKE, 1964:30; TAMURA & LAUENER, l.c), no puede usarse en tanto no se localice algún material de aquel en que se basó la descripción un tanto ambigua de Miller....

Senecio pterophorus DC., a new alien species in the European mainland

Senecio pterophorus DC. is an erect, semilignose shrub (fig. 1) which grows up to 2 m high. Is a chamaephyte basipetal branch-shedder (ORSHAN, Plant pheno-morphological studies in Mediterranean type ecosystems: 210-211. 1989) whose new branches appear below inflorescences but not from the lower parts of the plant. Leaves lanceolate. Stems are annual and develop at their apex a great number of small (up to 15 mm in diameter) yellow capitula which are grouped in a corymbose-paniculated inflorescence (HARVEY & SONDER, Flora Capensis: Cape Colony, Caffraria & Port Natal 3: 386.1865).

Disentangling the link between health and social capital: A comparison of immigrant and native-born populations in Spain

An increasing body of research has pointed to the relevance of social capital in studying a great variety of socio-economic phenomena, ranging from economics growth and development to educational attainment and public health. Conceptually, our paper is framed within the debates about the possible links between health and social capital, on one hand, and within the hypotheses regarding the importance of social and community networks in all stages of the dynamics of international migration, on the other hand. Our primary objective is to explore the ways social relations contribute to health differences between the immigrants and the native-born population of Spain. We also try to reveal differences in the nature of the social networks of foreign-born, as compared to that of the native-born persons. The empirical analysis is based on an individual-level data coming from the 2006 Spanish Health Survey, which contains a representative sample of the immigrant population. To assess the relationship between various health indicators (self-assessed health, chronic conditions and long-term illness) and social capital, controlling for other covariates, we estimate multilevel models separately for the two population groups of interest. In the estimates we distinguish between individual and community-level social capital. While the Health Survey contains information that allows us to define individual social capital measures, the collective indicators come from other official sources. In particular, for the subsample of immigrants, we proxy community-level networks and relationships by variables contained in the Spanish National Survey of Immigrants 2007. The results obtained so far point to the relevance of social capital as a covariate in the health equation, although, the significance varies according to the specific health indicator used. Additionally, and contrary to what is expected, immigrants’ social networks seem to be inferior to those of the native-born population in many aspects; and they also affect immigrant’s health to a lesser extent. Policy implications of the findings are discussed. Keywords: health status, social capital, immigration, Spain

Les Imitacions de vaixella fina importada a la Hispania Citerior (segles I aC-I dC)

Aquesta obra és fruit de la taula rodona «Imitatio Vasaria. Les imitacions de vaixella fina a la Hispània Citerior en època tardorepublicana i altimperial: producció i comercialització», que va reunir durant tres dies representants de tretze grups de recerca per reflexionar sobre les imitacions de les ceràmiques fines d’importació d’època romana tardorepublicana i altimperial. Com a resultat d’aquestes xerrades es van redactar 14 articles que presenten els estats de la qüestió que cada grup de recerca va portar a terme en el seu àmbit geogràfic i en els jaciments on van desenvolupar el seu treball de camp: diverses zones de la Hispània Citerior des de les universitats de Girona, Barcelona, Autònoma de Barcelona, València, Alacant i Valladolid, així com des dels Museus d’Arqueologia de Catalunya-Empúries, Mataró i Badalona, i de l’ICAC. Dos articles del llibre, però, se centren en un altre punt de la Mediterrània occidental, el Llenguadoc, aportat per un grup del Centre National de la Recherche Scientifique (CNRS).

Id Gene regulation and function in the prosensory domains of the chicken inner ear: a link between Bmp Signaling and Atoh1

Bone morphogenetic proteins (Bmps) regulate the expression of the proneural gene Atoh1 and the generation of hair cells in the developing inner ear. The present work explored the role of Inhibitor of Differentiation genes (Id1-3) in this process. The results show that Id genes are expressed in the prosensory domains of the otic vesicle, along with Bmp4 and Bmp7. Those domains exhibit high levels of the phosphorylated form of Bmp-responding R-Smads (P-Smad1,5,8), and of Bmp-dependent Smad transcriptional activity as shown by the BRE-tk-EGFP reporter. Increased Bmp signaling induces the expression of Id1-3 along with the inhibition of Atoh1. Conversely, the Bmp antagonist Noggin or the Bmp-receptor inhibitor Dorsomorphin elicit opposite effects, indicating that Bmp signaling is necessary for Id expression and Atoh1 regulation in the otocyst. The forced expression of Id3 is sufficient to reduce Atoh1 expression and to prevent the expression of hair cell differentiation markers. Together, these results suggest that Ids are part of the machinery that mediates the regulation of hair cell differentiation exerted by Bmps. In agreement with that, during hair cell differentiation Bmp4 expression, P-Smad1,5,8 levels and Id expression are downregulated from hair cells. However, Ids are also downregulated from the supporting cells which contrarily to hair cells exhibit high levels of Bmp4 expression, P-Smad1,5,8, and BRE-tk-EGFP activity, suggesting that in these cells Ids escape from Bmp/Smad signaling. The differential regulation of Ids in time and space may underlie the multiple functions of Bmp signaling during sensory organ development.

Population Size and Civil Conflict Risk: Is There A Causal Link?

[spa] La estimación del impacto del tamaño de la populación sobre la probabilidad de conflicto civil se complica por el sesgo de endogeneidad y las variables omitidas. Este artículo trata el problema de causalidad utilizando métodos de variables instrumentales en un panel de 37 países del África Sub-sahariana en el período 1981-2004. Encontramos que un aumento de la población en un 1% aumenta la probabilidad de conflicto civil por un 5.2%.