4,626 research outputs found
Industrialización y prefabricación en la Alemania de los 50. Las exposiciones de arquitectura
Díez Medina, Carmen: “Industrializacion y prefabricación en Alemania”. En el libro “Los años 50: la arquitectura española y su compromiso con la historia”, Universidad de Navarra, Ed. T6 Ediciones, Pamplona, 2000
Cognitive outcome and gamma noise power unrelated to neuregulin 1 and 3 variation in schizophrenia
Background
Neuregulins are a family of signalling proteins that orchestrate a broad range of cellular responses. Four genes encoding Neuregulins 1–4 have been identified so far in vertebrates. Among them, Neuregulin 1 and Neuregulin 3 have been reported to contribute to an increased risk for developing schizophrenia. We hypothesized that three specific variants of these genes (rs6994992 and rs3924999 for Neuregulin 1 and rs10748842 for Neuregulin 3) that have been related to this illness may modify information processing capacity in the cortex, which would be reflected in electrophysiological parameters (P3b amplitude or gamma noise power) and/or cognitive performance.
Methods
We obtained DNA from 31 patients with schizophrenia and 23 healthy controls and analyzed NRG1 rs6994992, NRG1 rs3924999 and NRG3 rs10748842 promoter polymorphisms by allelic discrimination with real-time polymerase chain reaction (PCR). We compared cognitive outcome, P300 amplitude parameters and an electroencephalographic measure of noise power in the gamma band between the groups dichotomized according to genotype.
Results
Contrary to our hypothesis, we could not detect any significant influence of variation in Neuregulin 1/Neuregulin 3 polymorphisms on cognitive performance or electrophysiological parameters of patients with schizophrenia.
Conclusions
Despite our findings, we cannot discard that other genetic variants and, more likely, interactions between those variants and with genetic variation related to different pathways may still influence cerebral processing in schizophrenia
Core competencies, matching, and the structure of foreign direct investment
We develop a matching model of foreign direct investment to study how multinational firms choose between greenfield investment, acquisitions, and joint ventures. For all entry modes, firms must invest in a continuum of tasks to bring a product to market. Each firm possesses a core competency in the task space, though firms are otherwise identical. For acquisitions and joint ventures, a multinational enterprise (MNE) must match with a local partner, where the local partner may provide complementary expertise within the task space. However, for joint ventures, investment in tasks is shared by multiple owners, and hence is subject to a holdup problem. In equilibrium, ex-ante identical multinational enter the local matching market, and ex post, three different types of ownership within a heterogeneous group of firms arise. Specifically, the worst matches dissolve and the MNEs invest greenfield, the middle matches form joint ventures, and the best matches integrate via mergers and acquisitions. We also show that joint ventures are more common when the host country produces products that are inferior to those produced in the source country, which explains why MNEs use joint ventures more frequently in less-developed countries. Finally, we extend the model to a simple two-period context to provide a rationale for one of the more salient features of joint ventures, namely, their instability
Efecte filtre d'espín en complexos de Fe
En aquest article es presenta un efecte filtre d'espín d'àmbit unimolecular sota condicions de corrent polaritzat. En ell demostrem com en capturar una molècula d'un complex thermal spin-crossover de Fe entre dos elèctrodes, quan un d'ells és o bé a o bé b polaritzat, el darrer cas presenta una conductància com a mínim cent vegades superior respecte al primer. Aquesta és la primera vegada que s'ha pogut estudiar experimentalment un fenomen de filtratge d'espín a temperatura ambient.In this article a single-molecule spin-filter effect under polarized current conditions is presented. We demonstrate that, on capturing a molecule with a Fe thermal spin-crossover complex between two electrodes, when one of these is either a or b polarized, the b polarized electrode is at least one hundred times more conductive than the a electrode. This is the first time that it has been possible to study a spin-filter phenomenon at room temperature conditions
Chiral transition-metal complexes as Brønsted-acid catalysts for the asymmetric Friedel-Crafts hydroxyalkylation of indoles.
The Friedel-Crafts reaction between 3,3,3-trifluoropyruvates and indoles is efficiently catalysed by the iridium complex [(η5-C 5Me5)Ir{(R)-Prophos}(H2O)][SbF 6]2 (1) with up to 84% ee. Experimental data and theoretical calculations support a mechanism involving the Brønsted-acid activation of the pyruvate carbonyl by the protons of the coordinated water molecule in 1. Water is not dissociated during the process and, therefore, the catalytic reaction occurs with no direct interaction between the substrates and the metal. This journal is © the Partner Organisations 2014.The authors acknowledge the Ministerio de Economía y Competitividad (MINECO, Grants CTQ2006-03030/BQU, CTQ2009-10303/BQU, CTQ2011-27033 and Consolider Ingenio 2010 CSD2006-003), Gobierno de Aragón (Grupo Consolidado: Catálisis Homogénea Enantioselectiva), Generalitat de Catalunya (2009SGR0259) and the ICIQ foundation for financial support. A. S. and R. R. acknowledge MINECO for predoctoral fellowships. S. D.-G. acknowledges MINECO for a “Torres Quevedo” contract.Peer Reviewe
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