Epitaxial growth of biferroic YMnO3(0001) on platinum electrodes

Epitaxial films of the biferroic YMnO3 (YMO) oxide have been grown on platinum-coated SrTiO3(1 1 1) and Al2O3(0 0 0 1) substrates. The platinum electrodes, (1 1 1) oriented, are templates for the epitaxy of the hexagonal phase of YMO with a (0 0 0 1) out-of-plane orientation, which is of interest as this is the polarization direction of YMO. X-ray diffractometry indicates the presence of two crystal domains, 60° rotated in-plane, in the Pt(1 1 1) layers which subsequently are transferred on the upperlaying YMO. Cross-section analysis by high-resolution transmission electron microscopy (HRTEM) of YMnO3/Pt/SrTiO3(1 1 1) shows high-quality epitaxy and sharp interfaces across the structure in the observed region. We present a detailed study of the epitaxial growth of the hexagonal YMO on the electrodes.

Nonempirical cluster-model study of the chemisorption of atomic hydrogen on the (111) surface of diamondlike crystals

The interaction of atomic hydrogen with C4H9, Si4H9, and Ge4H9 model clusters has been studied using all-electron and pseudopotential ab initio Hartree-Fock computations with basis sets of increasing flexibility. The results show that the effect of polarization functions is important in order to reproduce the experimental findings, but their inclusion only for the atoms directly involved in the chemisorption bond is usually sufficient. For the systems H-C4H9 and H-Si4H9 all-electron and pseudopotential results are in excellent agreement when basis sets of comparable quality are used. Besides, semiempirical modified-neglect-of-differential-overlap computations provide quite reliable results both for diamond and silicon and have been used to investigate larger model clusters. The results confirm the local nature of chemisorption and further justify the use of minimal X4H9 model clusters.

Solid-phase synthesis and NMR studies of modified oligonucleotides forming triplex helix and of oligonucleopeptides mimicking the topoisomerase I-DNA covalent complex

Report for the scientific sojourn carried out at the Institut de Biologia Molecular de Barcelona of the CSIC –state agency – from april until september 2007. Topoisomerase I is an essential nuclear enzyme that modulates the topological status of DNA, facilitating DNA helix unwinding during replication and transcription. We have prepared the oligonucleotide-peptide conjugate Ac-NLeu-Asn-Tyr(p-3’TTCAGAAGC5’)-LeuC-CONH-(CH2)6-OH as model compound for NMR studies of the Topoisomerase I- DNA complex. Special attention was made on the synthetic aspects for the preparation of this challenging compound especially solid supports and protecting groups. The desired peptide was obtained although we did not achieve the amount of the conjugate needed for NMR studies. Most probably the low yield is due to the intrinsic sensitive to hydrolysis of the phosphate bond between oligonucleotide and tyrosine. We have started the synthesis and the structural characterization of oligonucleotides carrying intercalating compounds. At the present state we have obtained model duplex and quadruplex sequences modified with acridine and NMR studies are underway. In addition to this project we have successfully resolved the structure of a fusion peptide derived from hepatitis C virus envelope synthesized by the group of Dr. Haro and we have synthesized and started the characterization of a modified G-quadruplex.

The size of the underground economy in Germany: A correction of the record and new evidence from the Modified-Cash-deposit-Ratio approach

Based on the Ahumada et al. (2007, Review of Income and Wealth) critique we revise existing estimates of the size of the German underground economy. Among other things, it turns out that most of these estimates are untenable and that the tax pressure induced size of the German underground economy may be much lower than previously thought. To this extent, German policy and law makers have been misguided during the last three decades. Therefore, we introduce the Modified-Cash-Deposit-Ratio (MCDR) approach, which is not subject to the recent critique and apply it to Germany for the period 1960 to 2008. JEL: O17, Q41, C22, Keywords: underground economy, shadow economy, cash-depositratio, currency demand approach, MIMIC approach

Modified differentials and basic cohomology for Riemannian foliations

We define a new version of the exterior derivative on the basic forms of a Riemannian foliation to obtain a new form of basic cohomology that satisfies Poincaré duality in the transversally orientable case. We use this twisted basic cohomology to show relationships between curvature, tautness, and vanishing of the basic Euler characteristic and basic signature.

On spectral properties of the modified convolution operator

Vegeu el resum a l'inici del document del fitxer adjunt.

Síntesis, caracterización y ensayos cinéticos del nanocomposite RuO2/TiO2/MWCNT/Pt en la producción fotocatalítica de combustibles solares bajo iluminación UV y VIS

Se prepararon partículas de nanocomposites basados en TiO2 y nanotubos de carbono multicapa platinizados para la obtención de combustibles solares. Se evaluó la actividad fotocatalítica del material en la producción de hidrógeno, en procesos de degradación de ácido fórmico, y en la obtención de hidrocarburos a partir de la reducción de CO2 en agua. Los nanocomposites fueron sintetizados por medio de la técnica sol-gel. Se estudió el efecto de la proporción y el diámetro de los nanotubos de carbono en la actividad del material bajo iluminación ultravioleta y visible. Se estudió el efecto de la adición de RuO2 (0,5% wt.) en la actividad bajo iluminación visible. Los materiales fueron caracterizados por ATR, XRD, BET, HRTEM y SEM. Se obtuvieron sólidos macroporosos, con contenido de fase anatasa superior al 99% y tamaño cristalino comprendido entre 15 y 21 nm. Los resultados cinéticos mostraron una producción óptima de hidrógeno para el composite TiO2/(5wt.%)MWCNT/Pt(60-80 nm), con eficiencia cuántica y eficiencia energética de 1,27% y 0,27%, respectivamente. En el caso de radiación visible, la producción de hidrógeno fue nula para los composites TiO2/MWCNT/Pt, mientras que para el sistema RuO2/TiO2/MWCNT/Pt se observó que la adicción de MWCNT inhibía la actividad fotocatalítica del composite RuO2/TiO2 en la región del visible. Por otra parte, en los ensayos de reducción de CO2 no se detectó ningún producto de reacción.

Preparation and properties of starch-based biopolymers modified with difunctional isocyanates

The present work reports on the preparation of thermoplastic starch (TPS) modified in situ with a diisocyanate derivative. Evidence of the condensation reaction between the hydroxyl groups of starch and glycerol with the isocyanate function (NCO) was confirmed by FTIR analysis. The evolution of the properties of the ensuing TPS, in term of mechanical properties, microstructure, and water sensitivity, was investigated using tensile mechanical, dynamic mechanical thermal analysis (DMTA), X-ray diffraction (XRD), and water uptake. The results showed that the addition of isocyanate did not affect the crystallinity of the TPS and slightly reduced the water uptake of the material. The evolution of the mechanical properties with ageing became less pronounced by the addition of the isocyanate as their amount exceeded 4 to 6wt%.

Traducción comentada de “Genetically Modified Organisms (GMOs): Transgenic Crops and Recombinant DNA Technology”

The purpose of this paper is to provide a translation into Spanish of a review articleabout genetically modified organisms (GMOs) entitled “Genetically ModifiedOrganisms (GMOs): Transgenic Crops and Recombinant DNA Technology” publishedby the well-known scientific journal Nature. In a world where English has become thelingua franca when it comes to transferring scientific knowledge and information, itmust be taken into account that not everyone—from scientist to the general public—hasa good enough command of English so that they can feel comfortable enough reading inthis language. Translators are consequently needed resulting from a great demand oftranslation activity into, for example, Spanish. This is the reason why the proposedSpanish translation is followed by a detailed analysis emphasizing the difficulties andproblems that characterize scientific—and also general—translation (i.e. terminology,syntax, semantics, pragmatics, and ideology), for which different approaches as how tosolve them are provided. On the basis of the analysis, it can be concluded thatexperience will be of much help to scientific translators, given that specificterminological knowledge and style requirements must always be born in mind whentranslating in this field. Moreover, this paper is intended to serve as a guide forTranslation students specializing in the field of science and the expectation is to helpthem make the right decisions when it comes to translating. However, it is clear that itcan only be thought of as an introduction that should be completed with further researchand documentation tasks in order to offer a complete reference tool: the ultimatehandbook of scientific translation.

The role of role uncertainty in modified dictator games

We compare behavior in modified dictator games with and without role uncertainty. Subjectschoose between a selfish action, a costly surplus creating action (altruistic behavior) and acostly surplus destroying action (spiteful behavior). While costly surplus creating actions are themost frequent under role uncertainty (64%), selfish actions become the most frequent withoutrole uncertainty (69%). Also, the frequency of surplus destroying choices is negligible with roleuncertainty (1%) but not so without it (11%). A classification of subjects into four differenttypes of interdependent preferences (Selfish, Social Welfare maximizing, Inequity Averse andCompetitive) shows that the use of role uncertainty overestimates the prevalence of SocialWelfare maximizing preferences in the subject population (from 74% with role uncertainty to21% without it) and underestimates Selfish and Inequity Averse preferences. An additionaltreatment, in which subjects undertake an understanding test before participating in theexperiment with role uncertainty, shows that the vast majority of subjects (93%) correctlyunderstand the payoff mechanism with role uncertainty, but yet surplus creating actions weremost frequent. Our results warn against the use of role uncertainty in experiments that aim tomeasure the prevalence of interdependent preferences.

Elicited beliefs and social information in modified dictator games: What do dictators believe other dictators do?

We use subjects actions in modified dictator games to perform a within-subject classification ofindividuals into four different types of interdependent preferences: Selfish, Social Welfaremaximizers, Inequity Averse and Competitive. We elicit beliefs about other subjects actions inthe same modified dictator games to test how much of the existent heterogeneity in others actions is known by subjects. We find that subjects with different interdependent preferences infact have different beliefs about others actions. In particular, Selfish individuals cannotconceive others being non-Selfish while Social Welfare maximizers are closest to the actualdistribution of others actions. We finally provide subjects with information on other subjects actions and re-classify individuals according to their (new) actions in the same modified dictatorgames. We find that social information does not affect Selfish individuals, but that individualswith interdependent preferences are more likely to change their behavior and tend to behavemore selfishly.

Estudi de la interacció de tres complexos de Pt amb proteïnes i oligonucleòtids mitjançant ESI-MS

En aquest treball s’investiga la reactivitat de tres complexos de Pt, cisplatí, complex 1, [Pt(dmba)(aza-N1)(dmso)], complex 2, i [Pt(dmba)(N9-9AA)(PPh3)]+, complex 3; els quals presenten activitat antitumoral, amb diferents proteïnes i oligonucleòtids mitjançant espectrometria de masses (ESI-TOF MS). ). L’estudi del cisplatí, 1, droga molt coneguda i emprada avui en dia pel tractament de molts tipus de càncer, permet comparar la reactivitat dels nous complexos d’estudi, 2 i 3, els quals presenten un IC50 més baix que el cisplatí en algunes línies de cèl·lules tumorals.

Programació d'una aplicació gràfica per l'anàlisi de senyals usant LDB (Local Discriminant Bases) i MLDB (Modified LDB)

Tot seguit presentem un entorn per analitzar senyals de tot tipus amb LDB (Local Discriminant Bases) i MLDB (Modified Local Discriminant Bases). Aquest entorn utilitza funcions desenvolupades en el marc d’una tesi en fase de desenvolupament. Per entendre part d’aquestes funcions es requereix un nivell de coneixement avançat de processament de senyals. S’han extret dels treballs realitzats per Naoki Saito [3], que s’han agafat com a punt de partida per la realització de l’algorisme de la tesi doctoral no finalitzada de Jose Antonio Soria. Aquesta interfície desenvolupada accepta la incorporació de nous paquets i funcions. Hem deixat un menú preparat per integrar Sinus IV packet transform i Cosine IV packet transform, tot i que també podem incorporar-n’hi altres. L’aplicació consta de dues interfícies, un Assistent i una interfície principal. També hem creat una finestra per importar i exportar les variables desitjades a diferents entorns. Per fer aquesta aplicació s’han programat tots els elements de les finestres, en lloc d’utilitzar el GUIDE (Graphical User Interface Development Enviroment) de MATLAB, per tal que sigui compatible entre les diferents versions d’aquest programa. En total hem fet 73 funcions en la interfície principal (d’aquestes, 10 pertanyen a la finestra d’importar i exportar) i 23 en la de l’Assistent. En aquest treball només explicarem 6 funcions i les 3 de creació d’aquestes interfícies per no fer-lo excessivament extens. Les funcions que explicarem són les més importants, ja sigui perquè s’utilitzen sovint, perquè, segons la complexitat McCabe, són les més complicades o perquè són necessàries pel processament del senyal. Passem cada entrada de dades per part de l’usuari per funcions que ens detectaran errors en aquesta entrada, com eliminació de zeros o de caràcters que no siguin números, com comprovar que són enters o que estan dins dels límits màxims i mínims que li pertoquen.

Structural and functional characterization of (110)-oriented epitaxial La2/3Ca1/3MnO3 electrodes and SrTiO3 tunnel barriers

La2/3Ca1/3MnO3 (LCMO) films have been deposited on (110)-oriented SrTiO3 (STO) substrates. X-ray diffraction and high-resolution electron microscopy reveal that the (110) LCMO films are epitaxial and anisotropically in-plane strained, with higher relaxation along the [1¿10] direction than along the [001] direction; x-ray absorption spectroscopy data signaled the existence of a single intermediate Mn3+/4+ 3d-state at the film surface. Their magnetic properties are compared to those of (001) LCMO films grown simultaneously on (001) STO substrates It is found that (110) LCMO films present a higher Curie temperature (TC) and a weaker decay of magnetization when approaching TC than their (001) LCMO counterparts. These improved films have been subsequently covered by nanometric STO layers. Conducting atomic-force experiments have shown that STO layers, as thin as 0.8 nm, grown on top of the (110) LCMO electrode, display good insulating properties. We will show that the electric conductance across (110) STO layers, exponentially depending on the barrier thickness, is tunnel-like. The barrier height in STO (110) is found to be similar to that of STO (001). These results show that the (110) LCMO electrodes can be better electrodes than (001) LCMO for magnetic tunnel junctions, and that (110) STO are suitable insulating barriers.