The black-white test score gap widens with age?

We re-examine the theoretical concept of a production function for cognitive achievement, and argue that an indirect production function that depends upon the variables that constrain parents' choices is both moretractable from an econometric point of view, and more interesting from an economic point of view than is a direct production function that depends upon a detailed list of direct inputs such as number of books in the household. We estimate flexible econometric models of indirect production functions for two achievement measures from the Woodcock-Johnson Revised battery, using data from two waves of the Child Development Supplement to the PSID. Elasticities of achievement measures with respect to family income and parents' educational levels are positive and significant. Gaps between scores of black and white children narrow or remain constant as children grow older, a result that differs from previous findings in the literature. The elasticities of achievement scores with respect to family income are substantially higher for children of black families, and there are some notable difference in elasticities with respect to parents' educational levels across blacks and whites.

News Shocks and Business Cycles: Bridging the Gap from Different Methodologies

An important disconnect in the news driven view of the business cycle formalized by Beaudry and Portier (2004), is the lack of agreement between different—VAR and DSGE—methodologies over the empirical plausibility of this view. We argue that this disconnect can be largely resolved once we augment a standard DSGE model with a financial channel that provides amplification to news shocks. Both methodologies suggest news shocks to the future growth prospects of the economy to be significant drivers of U.S. business cycles in the post-Greenspan era (1990-2011), explaining as much as 50% of the forecast error variance in hours worked in cyclical frequencies

Knowing the past to predict the future: land-use change and the distribution of invasive bullfrogs

Biological invasions and land-use changes are two major causes of the global modifications of biodiversity. Habitat suitability models are the tools of choice to predict potential distributions of invasive species. Although land-use is a key driver of alien species invasions, it is often assumed that land-use is constant in time. Here we combine historical and present day information, to evaluate whether land-use changes could explain the dynamic of invasion of the American bullfrog Rana catesbeiana (=Lithobathes catesbeianus) in Northern Italy, from the 1950s to present-day. We used maxent to build habitat suitability models, on the basis of past (1960s, 1980s) and present-day data on land-uses and species distribution. For example, we used models built using the 1960s data to predict distribution in the 1980s, and so on. Furthermore, we used land-use scenarios to project suitability in the future. Habitat suitability models predicted well the spread of bullfrogs in the subsequent temporal step. Models considering land-use changes predicted invasion dynamics better than models assuming constant land-use over the last 50 years. Scenarios of future land-use suggest that suitability will remain similar in the next years. Habitat suitability models can help to understand and predict the dynamics of invasions; however, land-use is not constant in time: land-use modifications can strongly affect invasions; furthermore, both land management and the suitability of a given land-use class may vary in time. An integration of land-use changes in studies of biological invasions can help to improve management strategies.

Tocant totes les tecles: Vicenç Sabater, un obrer de la música

Treball de recerca realitzat per un alumne d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientí­fic del Jovent l'any 2009. El treball tracta sobre la petita memòria històrica en la faceta de l'oci de la nostra societat , el ball i la música concretament, centrat en la memòria de l'avi de l'autor, músic, arranjador i compositor. Es tracta doncs, d'una investigació sobre la música de ball a Barcelona i a Catalunya, i en general també a Europa, atès que gràcies a les vivències d'en Vicenç Sabater (l'avi), es relata com era la seva feina i el seu ofici, el de músic. La recerca està ordenada cronològicament, començant pel seu naixement (1930), la formació i les primeres actuacions, passant per tota la seva vida personal, però sobretot professional, i conclou amb un epíleg sense el qual el treball de recerca no tindria sentit, ja que aquest explica com el Vicenç no s'ha jubilat mai, perquè sempre ha estat treballant amb la música, i perquè sempre que el seu físic li permeti, ell s'hi seguirà dedicant. El treball inclou un apartat destacat de la llarga etapa (30 anys) de Sabater amb el grup musical 'Rudy Ventura y su conjunto'. Molta d'aquesta informació s'obté a través d'entrevistes a dos dels cinc integrants del grup: el mateix Jaume Ventura, i en Joan Antoni Calvet, cantant i bateria, respectivament. Apartat que, dissortadament, s'ha convertit en el meu involuntari i modest homenatge a Jaume ('Rudy') Ventura , recentment traspassat.

The Wage-Productivity gap revisited: is the labour share neutral to employment?

This paper challenges the prevailing view of the neutrality of the labour income share to labour demand, and investigates its impact on the evolution of employment. Whilst maintaining the assumption of a unitary long-run elasticity of wages with respect to productivity, we demonstrate that productivity growth affects the labour share in the long run due to frictional growth (that is, the interplay of wage dynamics and productivity growth). In the light of this result, we consider a stylised labour demand equation and show that the labour share is a driving force of employment. We substantiate our analytical exposition by providing empirical models of wage setting and employment equations for France, Germany, Italy, Japan, Spain, the UK, and the US over the 1960-2008 period. Our findings show that the timevarying labour share of these countries has significantly influenced their employment trajectories across decades. This indicates that the evolution of the labour income share (or, equivalently, the wage-productivity gap) deserves the attention of policy makers.

Gestión de recursos en nodos multi-core de memoria compartida

La gestión de recursos en los procesadores multi-core ha ganado importancia con la evolución de las aplicaciones y arquitecturas. Pero esta gestión es muy compleja. Por ejemplo, una misma aplicación paralela ejecutada múltiples veces con los mismos datos de entrada, en un único nodo multi-core, puede tener tiempos de ejecución muy variables. Hay múltiples factores hardware y software que afectan al rendimiento. La forma en que los recursos hardware (cómputo y memoria) se asignan a los procesos o threads, posiblemente de varias aplicaciones que compiten entre sí, es fundamental para determinar este rendimiento. La diferencia entre hacer la asignación de recursos sin conocer la verdadera necesidad de la aplicación, frente a asignación con una meta específica es cada vez mayor. La mejor manera de realizar esta asignación és automáticamente, con una mínima intervención del programador. Es importante destacar, que la forma en que la aplicación se ejecuta en una arquitectura no necesariamente es la más adecuada, y esta situación puede mejorarse a través de la gestión adecuada de los recursos disponibles. Una apropiada gestión de recursos puede ofrecer ventajas tanto al desarrollador de las aplicaciones, como al entorno informático donde ésta se ejecuta, permitiendo un mayor número de aplicaciones en ejecución con la misma cantidad de recursos. Así mismo, esta gestión de recursos no requeriría introducir cambios a la aplicación, o a su estrategia operativa. A fin de proponer políticas para la gestión de los recursos, se analizó el comportamiento de aplicaciones intensivas de cómputo e intensivas de memoria. Este análisis se llevó a cabo a través del estudio de los parámetros de ubicación entre los cores, la necesidad de usar la memoria compartida, el tamaño de la carga de entrada, la distribución de los datos dentro del procesador y la granularidad de trabajo. Nuestro objetivo es identificar cómo estos parámetros influyen en la eficiencia de la ejecución, identificar cuellos de botella y proponer posibles mejoras. Otra propuesta es adaptar las estrategias ya utilizadas por el Scheduler con el fin de obtener mejores resultados.

Gender gap index in Spain by regions

Every year, the World Economic Forum publishes the World Gender Gap Report mainly based on the results of the Global Gender Gap Index (GGGI) computed by country. This index is made out of four subindexes to capture the magnitude of the gender gap in 4 areas: educational attainment, economic participation and opportunity, political empowerment, and health and survival; its methodology was reformed in 2006. In this paper we adapt the GGGI to construct a Regional Gender Gap Index (RGGI) and we compute it by regions (Comunidades Autónomas) in Spain with 2006 data. The RGGI could be applied to other regions. Results of the RGGI show that not only are there gender gap differences between Spanish regions in Spain, but that there are at the political empowerment and economic participation and opportunity categories that those differences are strongest. Geographic distribution of the gender gap shows that the deepest gaps are, in general, located in the northern regions (Euskadi, with a high score, and Murcia and Extremadura, with low scores, being exceptions); this is mainly due to the poor participation in politics of women in those regions.

Sex determination: why so many ways of doing it?

Sexual reproduction is an ancient feature of life on earth, and the familiar X and Y chromosomes in humans and other model species have led to the impression that sex determination mechanisms are old and conserved. In fact, males and females are determined by diverse mechanisms that evolve rapidly in many taxa. Yet this diversity in primary sex-determining signals is coupled with conserved molecular pathways that trigger male or female development. Conflicting selection on different parts of the genome and on the two sexes may drive many of these transitions, but few systems with rapid turnover of sex determination mechanisms have been rigorously studied. Here we survey our current understanding of how and why sex determination evolves in animals and plants and identify important gaps in our knowledge that present exciting research opportunities to characterize the evolutionary forces and molecular pathways underlying the evolution of sex determination.

Modulation of the gap junction protein Connexin36 in neurons in a mouse model of transient focalcerebral ischemia

Intercellular communication is achieved at specialized regions of the plasma membrane by¦gap junctions. Gap junctions are transmembrane channels allowing direct contacts between¦the cytoplasms of neighboring cells. Each cell participates with one hemichannel, or¦connexon, made of six protein subunits named connexins. Thanks to these junctions, cells¦potentially share a pool of small molecules and metabolites, such as nucleotides, amino acids¦and second messengers.¦In an ischemic (i.e. non-perfused) territory of the brain, irreversible damage progresses over¦time from the centre of the most severe flow reduction to the periphery with less disturbed¦perfusion. Functionally impaired tissue can survive and recover if sufficient reperfusion is reestablished¦within a limited time period, which depends on various factors and mechanisms¦modulating the signaling pathways leading to cell death.¦Observations were made indicating the presence of electrical coupling between neurons which¦resist better to an ischemic insult. This electrical coupling is likely to be mediated by¦Connexin36 (Cx36), a neuron specific connexin isoform. It was demonstrated in the past that¦global ischemia induces a selective upregulation of Cx36 expression in regions with neurons¦that survive the insult whereas others undergo apoptosis and die. These observations raise the¦possibility that the neuronal gap junction Cx36 might play a role in the destiny of neurons¦after cerebral ischemia.¦The aim of this work was to characterize the regulation of Connexin36 in a mouse model of¦transient focal cerebral ischemia by immunofluorescence and Western blot analysis. Our¦immunofluorescence results suggest a specific increase in Cx36 in the penumbral region of¦the ischemic hemisphere.

Decomposing the Tourist’s Satisfaction Gap: The Role of Expectations and Cognitions

In this paper we present an empirical methodology that allows the tourist’s satisfaction gap between two destinations to be decomposed into two components. One explains the role of differences in observed characteristics of the tourists and the stay (endowments). The other captures the share of the gap due to differences in the utility that tourists derive from those characteristics (cognitive). To illustrate the use of this method, we employ data coming from a sample of tourists visiting two touristic enclaves in Tarragona (Spain). Our results indicate that the cognitive component explains most of the satisfaction gap. Keywords: Satisfaction, expectations, cognition, touristic destination

The gap between scientific evidence and clinical practice : 5-aminosalicylates are frequently used for the treatment of Crohn's disease

BACKGROUND: There is uncertain evidence of effectiveness of 5-aminosalicylates (5-ASA) to induce and maintain response and remission of active Crohn's disease (CD), and weak evidence to support their use in post-operative CD. AIM: To assess the frequency and determinants of 5-ASA use in CD patients and to evaluate the physicians' perception of clinical response and side effects to 5-ASA. METHODS: Data from the Swiss Inflammatory Bowel Disease Cohort, which collects data since 2006 on a large sample of IBD patients, were analysed. Information from questionnaires regarding utilisation of treatments and perception of response to 5-ASA were evaluated. Logistic regression modelling was performed to identify factors associated with 5-ASA use. RESULTS: Of 1420 CD patients, 835 (59%) were ever treated with 5-ASA from diagnosis to latest follow-up. Disease duration >10 years and colonic location were both significantly associated with 5-ASA use. 5-ASA treatment was judged to be successful in 46% (378/825) of treatment episodes (physician global assessment). Side effects prompting stop of therapy were found in 12% (98/825) episodes in which 5-ASA had been stopped. CONCLUSIONS: 5-Aminosalicylates were frequently prescribed in patients with Crohn's disease in the Swiss IBD cohort. This observation stands in contrast to the scientific evidence demonstrating a very limited role of 5-ASA compounds in the treatment of Crohn's disease.