Production and characterization of metastable Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–TiO<Subscript>2</Subscript> ceramic materials

Producing nanostructured materials through metastable phases is interesting in the field of ceramic materials. Metastable phases can be obtained by the Atmospheric Plasma Spray (APS) technique which, is a well-known technique to produce coatings. The initial powders are melted during the spraying obtaining a homogenized phase due to their solubility in the liquid state. Afterwards, the molten droplets are quenched in a cooled medium, producing the sought metastable phases. Finally, during material consolidation, the metastable structure evolves due to a dual structure. A suppression of the grain growth is produced as a consequence of the immiscibility of both phases in the solid state. Due to their small grain size and uniform structure, these nanostructured materials exhibit very interesting properties such as higher hardness and toughness. The aim of this research has been to produce nanostructured Al₂O₃–TiO₂ ceramic powders through APS + quenching route, starting from commercially available micron-sized powders. A complete characterization of the obtained structures using XRD, SEM, FESEM and EDS has been carried out in the Thermal Spray Center (CPT) of the University of Barcelona.     

A WENO-Solver for the 1D Non-Stationary Boltzmann–Poisson System for Semiconductor Devices

In this work we present preliminary results of a high order WENO scheme applied to a new formulation of the Boltzmann equation (BTE) describing electron transport in semiconductor devices with a spherical coordinate system for the phase velocity space. The problem is two dimensional in the phase velocity space and one dimensional in the physical space, plus the time variable driving to steady states. The new formulation avoids the singularity due to the spherical coordinate system.     

Evaluation of organochlorine pesticide residues in human serum from an urban and two rural populations in Portugal

Organochlorine pesticide residues were measured in human serum from an urban and two rural populations in Portugal, in an attempt to evaluate the contamination level of Portuguese population. Serum levels of 12 residues were determined using a validated methodology that included gas chromatography-electron-capture detection. It was made an attempt to point out the differences of contamination between rural and urban populations; and among these, if it could be established a relation with sex and with age of individuals. p,p'DDE, alpha-hexachlorocyclohexane (HCH), p,p'DDD, and beta-HCH were the most frequently identified residues. p,p'DDE concentrations ranged from undetected to 390.5 microg/l in urban samples, and from undetected to 43.5 microg/l and to 171.2 microg/l in both rural samples. Maximum alpha-HCH concentration level was 114.4 microg/l in urban samples, 261.3 and 45.5 microg/l in both rural samples. Mean total DDT levels were always higher than mean total HCH levels. About p,p'DDE, in all three populations, the majority of the results above the limit of quantification were found among female sex. The analysis of different aged groups showed that younger groups continue to reveal contamination. Comparing obtained results with others from Europe, Asia and America, it was observed that Portugal is between the highest levels of contamination.     

Solution structure and stability of tryptophan-containing nucleopeptide duplexes

Covalently linked peptide-oligonucleotide hybrids were used as models for studying tryptophan-DNA interactions. The structure and stability of several hybrids in which peptides and oligonucleotides are linked through a phosphodiester bond between the hydroxy group of a homoserine (Hse) side chain and the 3'-end of the oligonucleotide, have been studied by both NMR and CD spectroscopy and by restrained molecular dynamics methods. The three-dimensional solution structure of the complex between Ac-Lys-Trp-Lys-Hse(p3'dGCATCG)-Ala-OH (p=phosphate, Ac=acetyl) and its complementary strand 5'dCGTAGC has been determined from a set of 276 experimental NOE distances and 33 dihedral angle constraints. The oligonucleotide structure is a well-defined duplex that belongs to the B-form family of DNA structures. The covalently linked peptide adopts a folded structure in which the tryptophan side chain stacks against the 3'-terminal guanine moiety, which forms a cap at the end of the duplex. This stacking interaction, which resembles other tryptophan-nucleobase interactions observed in some protein-DNA complexes, is not observed in the single-stranded form of Ac-Lys-Trp-Lys-Hse(p3'dGCATCG)-Ala-OH, where the peptide chain is completely disordered. A comparison with the pure DNA duplex, d(5'GCTACG3')-(5'CGTAGC3'), indicates that the interaction between the peptide and the DNA contributes to the stability of the nucleopeptide duplex. The different contributions that stabilize this complex have been evaluated by studying other nucleopeptide compounds with related sequences.     

Algorithms for Del Pezzo surfaces of degree 5 (construction, parametrization)

It is well known that every Del Pezzo surface of degree 5 defined over a field k is parametrizable over k. In this paper, we give an algorithm for parametrizing, as well as algorithms for constructing examples in every isomorphism class and for deciding equivalence.     

Space extreme design

This paper is an introduction to the following five articles, that have been conceived together as one chapter on habitability consideration for outer space habitations. Those contributions are made from authors in different fields, cultures and countries working with the Extreme-Design.eu research group. Projects, theories and requirements are referred to the context of outer space habitats, where for the love of knowledge, human beings are living under extreme condition. The group purpose is to apply holistic approach (using both scientific and humanity discipines) towards space habitat design to support human cultural experience and improve technical reliability. Space Anthropology, Space Design, Space Art and Space Psychology are the established disciplines here considered to have a bearing on astronaut reliability. With multidisciplinary contributions, natural design philosophy- and human-centred design, these papers aim of collecting a range of solutions and innovative ideas on how to increase habitability in space.     

Mining hot calling contexts in small space

Calling context trees (CCTs) associate performance metrics with paths through a program's call graph, providing valuable information for program understanding and performance analysis. In real applications, however, CCTs might easily consist of tens of millions of nodes, making them difficult to analyze and also hurting execution times because of poor access locality. For performance analysis, accurately mining only hot calling contexts may be more useful than constructing an entire CCT with millions of uninteresting paths, because the distribution of context frequencies is typically very skewed. In this article, we show how to exploit this property to considerably reduce the CCT size, introducing a novel runtime data structure, called hot CCT (HCCT), in the spectrum of representations for interprocedural control flow. The HCCT includes only hot nodes and their ancestors in a CCT and can be constructed independently from it by using fast, space‐efficient algorithms for mining frequent items in data streams. With this approach, we can distinguish between hot and cold contexts on the fly while obtaining very accurate frequency counts. We show, both theoretically and experimentally, that the HCCT achieves a similar precision as the CCT in a space that is several orders of magnitude smaller and roughly proportional to the number of hot contexts. Our approach can be effectively combined with previous context‐sensitive profiling techniques, as we show for static bursting. We devise an implementation as a plug‐in for the gcc compiler that incurs a slowdown competitive with the gprof call‐graph profiler while collecting finer‐grained profiles. Copyright © 2015 John Wiley & Sons, Ltd.     

The impact of an innovative instructional intervention on the acquisition of oral presentation skills in higher education

The present study focuses on the design and development of an instructional approach to develop oral presentation skills. The theoretical base builds on the social cognitive perspective, and self-regulated learning. The aim of the study is to investigate whether the design of a multimedia-based instructional format - comprising of a standardised multimedia instruction, practical activities and feedback - will enhance oral presentation skills. In the study, the differential effect of three ‘modes of feedback’ on performance has been researched. The results reveal that oral presentation skills did improve significantly after the instruction. The multimedia nature of the design was favoured by all participants. In contrast, no significant impact of feedback was found. Nevertheless, feedback proved to be a useful process that was highly welcomed by participants.