Gold phosphide complexes

6 pages, 9 schemes, 6 figures.The vast majority of gold complexes with five group-element donor ligands contain tertiary phosphines, although compounds with amine, arsine or stibine ligands are also known. Although phosphide ligands, which are formed by deprotonation of non-tertiary phosphines, are closely related to the former, they have been employed to a lesser extent, mainly due to their lower stability. Thus, the chemistry of phosphido-bridged derivatives of the main group elements1-3 or transition metals4-6 has been a matter of interest for various research groups in the last few years. While there are many phosphido complexes with metals, mainly of groups 67-12 or 10,13-20 the chemistry of gold derivatives has experienced less progress in this field of research in spite of the possible catalytic behaviour of di- and polynuclear phosphido-bridged compounds.21 This is an interesting field of research, because the substitution of one or more protons by metal atoms allows the synthesis of homo- or hetero-polynuclear compounds in which the presence of a small bridging atom, such as phosphorus, may give rise to intermetallic contacts, which, as is known, are often responsible for surprising and interesting optical properties, such as luminescence, area with an increasing importance in the last years. This review focuses on gold phospide complexes derived from secondary phosphines (PR2H), primary phosphines (PRH2), primary diphosphines (PH2(CH2)nPH2) or from PH3. The moieties derived from all these complexes usually act as bridging ligands between more than one gold centre or between gold and other transition metal centres.Peer reviewe

Characterisation of Technological Collaborations and Evolution in the Spanish Defence Industry

Collaboration with technological partners as an innovation strategy has become widespread in recent years, and all sectors are immersed in this process. In particular, the defence industry is characterised by the technological complexity of the products and services offered, together with a constant innovation process. However, data that allow us to identify characteristics that are found in collaboration contracts are not usually available in this sector. This paper addresses this gap in the literature by studying the different characteristics of both the technological partners and the development agreements for the 1999-2017 period. This is possible thanks to a database of more than 300 collaboration technology agreements between public and private organisations and the Spanish Ministry of Defence. The results provide the Ministry of Defence with a clear picture of the type of collaborations in the Defence industry, their partners and their behaviour under different economic conditions, which will help it identify the type of collaborations that can contribute to improving the design of its innovation strategy

Nuevos escenarios para la adquisición de conocimientos medioambientales. Una experiencia en la Facultad de Educación y Humanidades de Melilla

Desde el año 2006 se viene desarrollando en la Facultad de Educación y Humanidades de Melilla (UGR) el proyecto “Propuesta metodológica para el aprendizaje autónomo de conceptos medioambientales en la formación de maestros”, que nace con la intención de adecuar la metodología de la asignatura obligatoria Fundamentos científicos medioambientales, al sistema de enseñanza impulsado por el Espacio Europeo de Educación Superior a la vez que trata de dar respuesta a la escasez de recursos didácticos que relacionan el conocimiento del entorno local, en sus facetas ambiental y urbana, con los conocimientos que se deben trabajar en la formación inicial de los futuros maestros. En el presente trabajo se aportan algunos de los resultados obtenidos tras la puesta en práctica de una metodología activa en donde se combinan distintos escenarios de enseñanza-aprendizaje

Improved performance of LDPC-coded MIMO systems with EP-based soft-decisions

The proceeding at: IEEE International Symposium on Information Theory (ISIT 2014), took place 2014, June 29-July 04, in Honolulu (Hawai)Modern communications systems use efficient encoding schemes, multiple-input multiple-output (MIMO) and high-order QAM constellations for maximizing spectral efficiency. However, as the dimensions of the system grow, the design of efficient and low-complexity MIMO receivers possesses technical challenges. Symbol detection can no longer rely on conventional approaches for posterior probability computation due to complexity. Marginalization of this posterior to obtain per-antenna soft-bit probabilities to be fed to a channel decoder is computationally challenging when realistic signaling is used. In this work, we propose to use Expectation Propagation (EP) algorithm to provide an accurate low-complexity Gaussian approximation to the posterior, easily solving the posterior marginalization problem. EP soft-bit probabilities are used in an LDPC-coded MIMO system, achieving outstanding performance improvement compared to similar approaches in the literature for low-complexity LDPC MIMO decoding.This work has been partly funded by the Spanish Ministry of Science and Innovation with the projects GRE3NSYST (TEC2011-29006-C03-03) and ALCIT (TEC2012-38800-C03-01) and by the program CONSOLIDERINGENIO 2010 under the project COMONSENS (CSD 2008-00010).Publicad

Expectation Propagation Detection for High-Order High-Dimensional MIMO Systems

Modern communications systems use multiple-input multiple-output (MIMO) and high-order QAM constellations for maximizing spectral efficiency. However, as the number of antennas and the order of the constellation grow, the design of efficient and low-complexity MIMO receivers possesses big technical challenges. For example, symbol detection can no longer rely on maximum likelihood detection or sphere-decoding methods, as their complexity increases exponentially with the number of transmitters/receivers. In this paper, we propose a low-complexity high-accuracy MIMO symbol detector based on the Expectation Propagation (EP) algorithm. EP allows approximating iteratively at polynomial-time the posterior distribution of the transmitted symbols. We also show that our EP MIMO detector outperforms classic and state-of-The-Art solutions reducing the symbol error rate at a reduced computational complexity.This work has been partly funded by the Spanish Ministry of Science and Innovation with the projects GRE3NSYST (TEC2011- 29006-C03-03) and ALCIT (TEC2012-38800-C03-01) and by the program CONSOLIDER-INGENIO 2010 under the project COMONSENS (CSD 2008- 00010).Publicad

Linking Spanish wine farmers to international markets: Is direct export better than indirect export in improving farm performance?

Selecting an appropriate export channel is one of farmers’ most important strategic decisions as it determines farm performance. Although direct and indirect exports are two important channels linking farmers to international markets, little is known about whether direct export is better than indirect export in improving farm performance. This study addresses this research gap by analyzing the impact of export channel choice on wine export farm performance, utilizing data collected from 479 wine-exporting farmers from Spain. An inverse probability-weighted regression adjustment estimator addresses the selection bias issue of export channel choice. The results show that the wine export price received by the direct exporters is significantly lower than that received by the indirect exports. Using domestic intermediaries for exportation (i.e. indirect export) can reduce information asymmetry and transaction costs, which enable indirect wine exporters to sell their products at higher prices. However, there are no significant differences between direct and indirect exporters in export volume, value, diversity, and satisfaction. The findings highlight that direct and indirect exports do not generate differentiated profits, and wine farmers should choose one of them that can facilitate their access to international markets

Experimental and theoretical evidence of the first Au(I)Bi(III) interaction

3 pages, 3 figures, 1 scheme.-- Published as an advance article on the web 15th Nov. 2006.Complex [Au(C6F5)2][Bi(C6H4CH2NMe2-2)2] 1 displays the first example of an interaction between Au(I) and Bi(III), the nature of which is shown to be consistent with the presence of a high ionic contribution (79%) and a dispersion type (van der Waals) interaction (21%).The D.G.I.(MEC)/FEDER (CTQ2004-05495) project is acknowledged. M. Monge thanks the MEC-UR for his contract ‘‘Ramón y Cajal’’. EC through the Socrates/Erasmus program (M. Nema) and a NATO research fellowship (C. Silvestru) are also acknowledged.Peer reviewe

Collaborative writing of argumentative syntheses by low-performing undergraduate writers: explicit instruction and practice

In writing argumentative syntheses from multiple and contradictory sources, students must contrast and integrate different perspectives on a topic or issue. This complex task of source-based argumentation has been shown to be effective for learning, but it has also been shown to be quite challenging. Because of the challenges, educational interventions have been developed to facilitate performance through such means as explicit instruction of strategies and students’ engagement in collaborative writing. Whereas these interventions have been beneficial for many writers, some students continue to perform poorly. The present study builds on prior research into collaborative writing of source-based argumentative syntheses by focusing on these students who experience difficulty with this academic task. Undergraduate psychology students who had previously underperformed on the argumentative task were organized into 56 pairs to participate in one of four versions of an intervention program, which differed in terms of the extent of support provided. The most complete program included collaboration as well as explicit instruction in argumentative synthesis writing and in the collaboration process. Statistical analyses were carried out with two ANOVAs with planned comparisons as well as two mediation models. Results showed that the pairs of students who received this most complete program significantly improved the quality of their synthesis in two dimensions, argument identification and argument analysis. The quality of their performance exceeded the performance of students in the three other intervention programs. The combination of explicit instruction and practice in pairs had positive effects on argument identification; but, for argument integration, effectiveness could be attributed solely to the explicit instruction component of the intervention. The study contributes to prior research by showing how the components of an intervention can make differential contributions to its effectiveness for a particular group of studentsThe present study was supported by the Ministerio de Ciencia e Innovación State program oriented to the challenges of society (I + D + i) (PID2019-105250RB-I00