Doping dependent Irreversible Magnetic Properties of Ba(Fe1-xCox)2As2 Single Crystals

We discuss the irreversible magnetic properties of self-flux grown Ba(Fe1-xCox)2As2 single crystals for a wide range of concentrations covering the whole phase diagram from the underdoped to the overdoped regime, x=0.038, 0.047, 0.058, 0.071, 0.074, 0.10, 0.106 and 0.118. Samples were characterized by a magneto-optical method and show excellent spatial uniformity of the superconducting state. The overall behavior closely follows classical Bean model of the critical state. The field-dependent magnetization exhibits second peak at a temperature and doping - dependent magnetic field, Hp. The evolution of this fishtail feature with doping is discussed. Magnetic relaxation is time-logarithmic and unusually fast. Similar to cuprates, there is an apparent crossover from collective elastic to plastic flux creep above Hp. At high fields, the field dependence of the relaxation rate becomes doping independent. We discuss our results in the framework of the weak collective pinning and show that vortex physics in iron-based pnictide crystals is much closer to high-Tc cuprates than to conventional s-wave (including MgB2) superconductors.Comment: for the special issue of Physica C on iron-based pnictide superconductor

Children’s Verbal, Visual and Spatial Processing and Storage Abilities: An Analysis of Verbal Comprehension, Reading, Counting and Mathematics

The importance of working memory (WM) in reading and mathematics performance has been widely studied, with recent research examining the components of WM (i.e., storage and processing) and their roles in these educational outcomes. However, the differing relationships between these abilities and the foundational skills involved in the development of reading and mathematics have received less attention. Additionally, the separation of verbal, visual and spatial storage and processing and subsequent links with foundational skills and downstream reading and mathematics has not been widely examined. The current study investigated the separate contributions of processing and storage from verbal, visual and spatial tasks to reading and mathematics, whilst considering influences on the underlying skills of verbal comprehension and counting, respectively. Ninety-two children aged 7- to 8-years were assessed. It was found that verbal comprehension (with some caveats) was predicted by verbal storage and reading was predicted by verbal and spatial storage. Counting was predicted by visual processing and storage, whilst mathematics was related to verbal and spatial storage. We argue that resources for tasks relying on external representations of stimuli related mainly to storage, and were largely verbal and spatial in nature. When a task required internal representation, there was a draw on visual processing and storage abilities. Findings suggest a possible meaningful separability of types of processing. Further investigation of this could lead to the development of an enhanced WM model, which might better inform interventions and reasonable adjustments for children who struggle with reading and mathematics due to WM deficits

Working memory and high-level cognition in children: An analysis of timing and accuracy in complex span tasks

This study examined working memory (WM) using complex span tasks (CSTs) to improve theoretical understanding of the relationship between WM and high-level cognition (HLC) in children. Ninety-two children aged between seven and eight years were tested on three computer-paced CSTs and measures of non-verbal reasoning, reading and mathematics. Processing times in the CSTs were restricted based on individually titrated processing speeds, and performance was compared to participant-led tasks with no time restrictions. Storage, processing accuracy, and both processing and recall times within the CSTs were used as performance indices to understand the effects of time restrictions at a granular level. Restricting processing times did not impair storage, challenging models that argue for a role of maintenance in WM. A task-switching account best explained the effect of time restrictions on performance indices and their inter-relationships. Principal component analysis showed that a single factor with all performance indices from just one CST (Counting span) was the best predictor of HLC. Storage in both the participant-led and computer-paced versions of this task explained unique and shared variance in HLC. However, the latter accounted for more variance in HLC when contributions from processing time were included in the model. Processing time in this condition also explained variance above and beyond storage. This suggests that faster processing is important to keep information active in WM; however, this is only evident when time restrictions are placed on the task and important when WM performance is applied in broader contexts that rely on this resource

Zeolite-Catalyzed Isobutene Amination: Mechanism and Kinetics

Amination of isobutene with NH was investigated over Brønsted acidic zeolites at 1 atm and 453-483 K. To compare catalytic activities over different zeolites, the measured reaction rates are normalized by the number of active sites determined by tert-butylamine temperature-programmed desorption (TPD). Small- A nd medium-pore zeolites with one-dimensional channels exhibit low activity because of pore blockage by adsorbed tert-butylammonium ions. However, turnover frequencies and activation energies are not sensitive to framework identity, as long as the active site is accessible to isobutene and tert-butylamine. Kinetic measurements and FTIR spectroscopy reveal that the Brønsted acid sites in MFI are covered predominantly with tert-butylammonium ions under reaction conditions. The desorption of tert-butylamine is assisted by the concurrent adsorption of isobutene. DFT simulations show that at very low tert-butylamine partial pressures, for example, at the inlet to the reactor, tert-butylamine desorption is rate-limiting. However, at sufficiently high tert-butylamine partial pressures (>0.03 kPa), protonation of isobutene to the corresponding carbenium ion limits the rate of amination.

Oligomerization of amyloid Abeta peptides using hydrogen bonds and hydrophobicity forces

The 16-22 amino acid fragment of the beta-amyloid peptide associated with the Alzheimer's disease, Abeta, is capable of forming amyloid fibrils. Here we study the aggregation mechanism of Abeta(16-22) peptides by unbiased thermodynamic simulations at the atomic level for systems of one, three and six Abeta(16-22) peptides. We find that the isolated Abeta(16-22) peptide is mainly a random coil in the sense that both the alpha-helix and beta-strand contents are low, whereas the three- and six-chain systems form aggregated structures with a high beta-sheet content. Furthermore, in agreement with experiments on Abeta(16-22) fibrils, we find that large parallel beta-sheets are unlikely to form. For the six-chain system, the aggregated structures can have many different shapes, but certain particularly stable shapes can be identified.Comment: 19 pages, 7 figures (to appear in Biophys. J.

Global hydrodynamic analysis of the molecular flexibility of galactomannans

In the past, intrinsic viscosity and sedimentation velocity analyses have been used separately to assess the conformation and flexibility of guar and locust bean gum galactomannans based on worm-like chain and semi-flexible coil models. Publication of a new global method combining data sets of both intrinsic viscosity and sedimentation coefficient with molecular weight, and minimising a target (error) function now permits a more robust analysis. Using this approach, values for the persistence length of (10 ± 2) nm for guar and (7 ± 1) nm for locust bean gum are returned if the mass per unit length ML is floated as a variable. Using a fixed mass per unit length based on the known compositional data of each galactomannan yields a similar value for Lp in both cases, (8 ± 1) nm for guar and (9 ± 1) nm for locust bean gum, with combined set of data yielding (9 ± 1) nm: within experimental error the flexibilities of both galactomannans are very similar. © 2007 Elsevier Ltd. All rights reserved

The restoration of the plateresque facade of Saint Ildephonse college at the University of Alcalá

[EN] This college, founded by Cardinal Cisneros in 1498, is the heart of the University of Alcalá. Its façade is a National Monument since 1914. Restorations undertaken in the twentieth century allowed to preserve it, but the deterioration of some materials used in them, produced 75 years later, the release of stone fragments with risk of accident and irrecoverable losses in their valuable carvings and historical patinas. Last restoration (2016-2017) has analyzed the materials and techniques with which it was built and with which it was restored in the historical intervention of the early twentieth century. From this, the façade has been restored again, to guarantee the conservation of its different types of stone and patinas that, while still preserved in some protected areas, improve the understanding of the character of this fundamental work of Spaniard Plateresque architecture.[ES] Este colegio, fundado por el cardenal Cisneros en 1498 es el corazón de la Universidad de Alcalá. Su fachada es Monumento Nacional desde 1914. Las restauraciones del siglo XX permitieron conservarla, pero el deterioro de algunos materiales empleados en ellas, provocó 75 años después el desprendimiento de fragmentos de piedra con riesgo de accidente y de pérdidas irrecuperables en sus valiosas tallas y pátinas históricas. La última restauración (2016-2017) ha analizado los materiales y las técnicas con los que se edificó y restauró en la intervención histórica de principios del siglo XX. Desde entonces, se ha intervenido sobre ella para garantizar la conservación de sus diferentes tipos de piedra y de las pátinas preservadas en las zonas más resguardadas que, una vez recuperadas, ayudan a comprender mejor el carácter original de esta obra fundamental de la arquitectura plateresca española.De La Quintana Gordon, JL.; García De Miguel, JM.; Sánchez-Barriga Fernández, A. (2018). La restauración de la fachada plateresca del colegio mayor de San Ildefonso de la Universidad de Alcalá. Loggia, Arquitectura & Restauración. (31):92-107. doi:10.4995/loggia.2018.10581SWORD9210731AGA, 51,11282AGA, F-00165-05-04 a AGA, F-00165-05-17A.A.V.V. Estudio petrológico previo a la restauración de la fachada. UPM, 1990A.A.V.V. "The orange-brown patina of Salisbury cathedral (west porch). Surfaces: evidence of its man-made origin". Environmental science and pollution research, Vol. 12, nº 5, pp 285-289, 2005. https://doi.org/10.1065/espr2005.05.257BATAILLON, M. Erasmo y España, (1ª ed. en francés, 1937), Madrid 2006.CAMÓN AZNAR, J. La Arquitectura Plateresca, Madrid, 1945CASTILLO OREJA, M.A. Colegio Mayor de San Ildefonso de Alcalá de Henares, Génesis y desarrollo de su construcción. Siglos XV - XVIII. p. 37, Ayto. de Alcalá de Henares, 1980DE SAGREDO, D. Medidas del romano, Toledo, 1526DORREGO, M. P. LUXÁN. F, SOTOLONGO, R. "Los trabadillos: Origen, utilización y técnicas de preparación". Actas del Segundo Congreso Nacional de Historia de la Construcción, A Coruña, 1998GALLEGO DE MIGUEL, A. "El taller de Cristóbal de Andino". Boletín de la Real Academia de Bellas Artes de San Fernando nº 74, p 199, 1992Manuscrito Mss/8884 Biblioteca Nacional de Madrid. También GARCÍA, S. Compendio de architectura y simetría de los templos. Edición Antonio Bonet. Colegio Oficial de Arquitectos. Madrid 1991GARCÍA, Compendio de architectura y simetría de los templos. Edición Antonio Bonet. Colegio Oficial de Arquitectos. Madrid 1991GARCÍA DE MIGUEL, J.M. Memoria para la restauración de la fachada, 2015GÓMEZ MORENO, M. Las Águilas del Renacimiento Español. Xarait ediciones, 1983 de estudios gallegos, Vol 13, pp 173-194GONZÁLEZ NAVARRO, R. La fachada de San Ildefonso, un nuevo relato visual de una universidad en el siglo XVI. Ramón González Navarro, Alcalá de Henares, 2017. p. 41 HOAG, D.J. Rodrigo Gil de Hontañón, Xarait. Madrid, 1985LAZZARINI, L. SALVATORI, O. "A reassessment of the formation of the patina called scialbatura". Studies in conservation, Vol. 34, nº 1, pp 20-26, 1989C. Sabbioni, G. Zappia, "Oxalate patinas on ancient monuments: the biological hypothesis". Aerobiologia nº 7. Pp 31-37, 1991.LLAGUNO Y AMÍROLA, E. Noticias de los arquitectos y arquitectura en España desde su restauración. Madrid, 1829MARÍAS, F. Orden Arquitectónico y Autonomía Universitaria: La fachada de la Universidad de Alcalá de Henares y Luis Vega. Goya, Nº 217-218 ,1990. pp 28-40NAVASCUÉS PALACIO, P. El Colegio Mayor Fonseca y su Arquitectura. Dragados y construcciones, Madrid, 1993 pp. 52-71NAVASCUÉS PALACIO, P. "Rodrigo Gil y los entalladores de la fachada de la Universidad de Alcalá". Archivo español de arte,Vol. 45, Nº 178, 1972, pp.103-118PARRA CREGO, E. Análisis en la restauración de la fachada, 2016-2017PITA ANDRADE, J.M. "Don Alonso de Fonseca y el arte del renacimiento". CuadernosPITA ANDRADE, J.M. Primera visita a la provincia. Instituto de Estudios Madrileños. Madrid. 1953PLINIO, G. Historia Natural, XXXVI, pp. 55,177PONZ PIQUER, A. Viaje de España. Tomo I, cartas sexta y séptima. Madrid, 178

Temporal fluctuation of multidrug resistant salmonella typhi haplotypes in the mekong river delta region of Vietnam.

BACKGROUND: typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina) assay to type 1,500 single nucleotide polymorphisms (SNPs) and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. PRINCIPAL FINDINGS: the population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the Sông H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. SIGNIFICANCE: the H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2) observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam