732 research outputs found
Development of brainstem-evoked responses in congenital auditory deprivation
To compare the development of the auditory system in hearing and completely acoustically deprived animals, naive congenitally deaf white cats (CDCs) and hearing controls (HCs) were investigated at different developmental stages from birth till adulthood. The CDCs had no hearing experience before the acute experiment. In both groups of animals, responses to cochlear implant stimulation were acutely assessed. Electrically evoked auditory brainstem responses (E-ABRs) were recorded with monopolar stimulation at different current levels. CDCs demonstrated extensive development of E-ABRs, from first signs of responses at postnatal (p.n.) day 3 through appearance of all waves of brainstem response at day 8 p.n. to mature responses around day 90 p.n.. Wave I of E-ABRs could not be distinguished from the artifact in majority of CDCs, whereas in HCs, it was clearly separated from the stimulus artifact. Waves II, III, and IV demonstrated higher thresholds in CDCs, whereas this difference was not found for wave V. Amplitudes of wave III were significantly higher in HCs, whereas wave V amplitudes were significantly higher in CDCs. No differences in latencies were observed between the animal groups. These data demonstrate significant postnatal subcortical development in absence of hearing, and also divergent effects of deafness on early waves II–IV and wave V of the E-ABR
Effect of alloying elements in melt spun Mg-alloys for hydrogen storage
In this paper we report the effect of alloying elements on hydrogen storage properties of melt-spun Mg-based alloys. The base alloys Mg90Si10, Mg90Cu10, Mg65Cu35 (at%) were studied. We also investigated the effect of rare earths (using MM: mischmetal) and Al in Mg65Cu25Al10, Mg65Cu25MM10 and Mg65Cu10Al15MM10 alloys. All the melt-spun alloys without MM show a crystalline structure, and the Mg65Cu25MM10 and Mg65Cu10Al15MM10 alloys showed an amorphous and partially amorphous structure respectively. At 350˚C all the alloys had a crystalline structure during the hydrogen absorption-desorption tests. It was observed that Si and Cu in the binaries alloys hindered completely the activation of thehydrogen absorption. The partial substitution of Cu by MM or Al allowed activation. The combined substitution of Cu by MM and Al showed the best results with the fastest absorption and desorption kinetics, which suggests that this combination can be used for new Mg-alloys to improve hydrogen storage properties.Fil: Rozenberg, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería ; ArgentinaFil: Saporiti, María Fabiana Sonia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería ; ArgentinaFil: Lang, Julien. Université du Québec a Montreal; CanadáFil: Audebert, Fernando Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Botta, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Stoica, Mihai. Leibniz Institute for Solid State and Materials Research Dresden; AlemaniaFil: Huot, Jacques. Université du Québec a Montreal; CanadáFil: Eckert, Jürgen. The Erich Schmid Institute of Materials Science; Austri
Improving Requirements Engineering within the European Space Industry
International audienceThe Next Generation Requirements Engineering (NextGenRE) (ESA/ESTEC Contract 4000101353/10/NL/SFe) project seeks to identify possibilities to improve the requirements engineering process within the European Space industry in connection with Model-based System Engineering (MBSE)
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ABSTRACT. We examined whether Anxiety Sensitivity (AS) and Experiential Avoidance (EA), two potentially relevant constructs in the evolution of anxiety and related disorders with significant implications for cognitive-behavioral treatments, differentially relate to symptom expressions of patients with panic disorder and agoraphobia. Within a multi-center study 369 patients meeting the DSM-IV-TR criteria for panic disorder with agoraphobia (PD/AG) completed the multidimensional Panic and Agoraphobia Scale (PAS), the Anxiety Sensitivity Index (ASI), the Acceptance and Action Questionnaire-II (AAQ-II) and the Beck Depression Inventory-II (BDI-II). Overlap, distinctiveness, and predictive validity of AS and EA were examined using explorative item analyses and multiple hierarchical regression analyses. AS and EA moderately correlated wit
Spontaneous chiral symmetry breaking in QCD:a finite-size scaling study on the lattice
Spontaneous chiral symmetry breaking in QCD with massless quarks at infinite
volume can be seen in a finite box by studying, for instance, the dependence of
the chiral condensate from the volume and the quark mass. We perform a
feasibility study of this program by computing the quark condensate on the
lattice in the quenched approximation of QCD at small quark masses. We carry
out simulations in various topological sectors of the theory at several
volumes, quark masses and lattice spacings by employing fermions with an exact
chiral symmetry, and we focus on observables which are infrared stable and free
from mass-dependent ultraviolet divergences. The numerical calculation is
carried out with an exact variance-reduction technique, which is designed to be
particularly efficient when spontaneous symmetry breaking is at work in
generating a few very small low-lying eigenvalues of the Dirac operator. The
finite-size scaling behaviour of the condensate in the topological sectors
considered agrees, within our statistical accuracy, with the expectations of
the chiral effective theory. Close to the chiral limit we observe a detailed
agreement with the first Leutwyler-Smilga sum rule. By comparing the mass, the
volume and the topology dependence of our results with the predictions of the
chiral effective theory, we extract the corresponding low-energy constant.Comment: 24 pages, 8 figure
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Effect of Alloying Elements in Melt Spun Mg-alloys for Hydrogen Storage
In this paper we report the effect of alloying elements on hydrogen storage properties of melt-spun Mg-based alloys. The base alloys Mg90Si10, Mg90Cu10, Mg65Cu35 (at%) were studied. We also investigated the effect of rare earths (using MM: mischmetal) and Al in Mg65Cu25Al10, Mg65Cu25MM10 and Mg65Cu10Al15MM10 alloys. All the melt-spun alloys without MM show a crystalline structure, and the Mg65Cu25MM10 and Mg65Cu10Al15MM10 alloys showed an amorphous and partially amorphous structure respectively. At 350˚C all the alloys had a crystalline structure during the hydrogen absorption-desorption tests. It was observed that Si and Cu in the binaries alloys hindered completely the activation of the hydrogen absorption. The partial substitution of Cu by MM or Al allowed activation. The combined substitution of Cu by MM and Al showed the best results with the fastest absorption and desorption kinetics, which suggests that this combination can be used for new Mg-alloys to improve hydrogen storage properties
Enhanced molecular analyses by combination of the HOPE-technique and laser microdissection
As part of an investigation aimed at illuminating the possibilities and limits of the HOPE-fixation and paraffin-embedding technique we here describe a novel procedure which was developed in order to combine the benefits of the HOPE-technique with the capabilities of laser microdissection. The presented procedure avoids the need for amplification of template-RNA thus facilitating reliable and reproducible results. The excellent preservation of nucleic acids, proteins, and morphology in HOPE-fixed, paraffin-embedded tissues enhances the molecular applications available to date with materials acquired by laser microdissection when compared to formalin fixed, paraffin-embedded tissues, thus substantially extending the methodological panel in tissue based research
The Nf=0 heavy quark potential from short to intermediate distances
We study the potential of a static quark anti-quark pair in the range 0.05fm
\leq r \leq 0.8fm, employing a sequence of lattices up to 64^4. Lattice
artifacts in potential and force are investigated theoretically as well as
numerically and continuum quantities are obtained by extrapolation of the
results at finite lattice spacing. Consistency of the numerical results with
the form of scaling violations predicted by an analysis `a la Symanzik is
found. The scale r_0/a is determined for the Wilson action up to beta=6.92.Comment: 24 pages (incl. tables), Late
An activation domain of plasmid R1 TraI protein delineates stages of gene transfer initiation
Bacterial conjugation is a form of type IV secretion that transports protein and DNA to recipient cells. Specific bacteriophage exploit the conjugative pili and cell envelope spanning protein machinery of these systems to invade bacterial cells. Infection by phage R17 requires F-like pili and coupling protein TraD, which gates the cytoplasmic entrance of the secretion channel. Here we investigate the role of TraD in R17 nucleoprotein uptake and find parallels to secretion mechanisms. The relaxosome of IncFII plasmid R1 is required. A ternary complex of plasmid oriT, TraD and a novel activation domain within the N-terminal 992 residues of TraI contributes a key mechanism involving relaxase-associated properties of TraI, protein interaction and the TraD ATPase. Helicase-associated activities of TraI are dispensable. These findings distinguish for the first time specific protein domains and complexes that process extracellular signals into distinct activation stages in the type IV initiation pathway. The study also provided insights into the evolutionary interplay of phage and the plasmids they exploit. Related plasmid F adapted to R17 independently of TraI. It follows that selection for phage resistance drives not only variation in TraA pilins but diversifies TraD and its binding partners in a plasmid-specific manner
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