Initial growth stages of epitaxial BaTiO3 films on vicinal SrTiO3 : Nb (001) substrates

The growth mechanism of epitaxial BaTiO3 films on vicinal Nb-doped SrTiO3 (srTiO(3):Nb) (001) substrate surfaces was studied in terms of surface morphology, crystalline orientation, microstructure, and film/substrate interface. Well-oriented BaTiO3 thin films were grown on SrTiO3 substrates with well-defined terraces by pulsed laser deposition. The regularly terraced TiO2-terminated surfaces of vicinal SrTiO3:Nb (001) substrates were prepared by a definite chemical and thermal treatment. Under our conditions, BaTiO3 seems to grow with a layer-then-island (Stranski-Krastanov) growth mechanism. In order to investigate the orientation and crystallinity of the BaTiO3 films, x-ray diffraction and high-resolution transmission election microscopy were performed. Ferroelectricity of the BaTiO3 films was proved by electrical measurements performed on Pt/BaTiO3/SrTiO3:Nb heterostructures.

Speed tuning of direction repulsion describes an inverted U-function

Direction repulsion describes the phenomenon in which observers typically overestimate the direction difference between two superimposed motions moving in different directions (Marshak & Sekuler, Science 205(1979) 1399). Previous research has found that, when a relatively narrow range of distractor speeds is considered, direction repulsion of a target motion increases monotonically with increasing speed of the distractor motion. We sought to obtain a more complete measurement of this speed-tuning function by considering a wider range of distractor speeds than has previously been used. Our results show that, contrary to previous reports, direction repulsion as a function of distractor speed describes an inverted U-function. For a target of 2.5deg/s, we demonstrate that the attenuation of repulsion magnitude with high-speed disractors can be largely explained in terms of the reduced apparent contrast of the distractor. However, when we reduce target motion speed, this no longer holds. When considered from the perspective of Edwards et al.s (Edwards, Badcock, & Smith, Vision Research 38 (1998) 1573) two global-motion channels, our results suggest that direction repulsion is speed dependent when the distractor and target motions are processed by different globalmotion channels, but is not speed dependent when both motions are processed by the same, high-speed channel. The implications of these results for models of direction repulsion are discussed.

Is screening for Factor V Leiden and Prothrombin G20210A Mutations in Renal Transplantation worthwhile? Results of a large single-center U.K. study

This single center study is the largest series of renal transplant recipients and donors screened for the commonest prothrombotic genotypes. A total of 562 transplant recipients and 457 kidney donors were genotyped for the factor V Leiden and prothrombin G20210A mutations. The prevalence of heterozygous factor V Leiden was 3.4% and 2.6% and prothrombin G20210A was 2.0% and 1.1% in recipients and donors, respectively, similar frequencies to that of the general U.K. population. The 30-day and 1-year graft survival rates in recipients with thrombophilic mutations were 93% and 93%, compared with 88% and 82% in patients without these mutations (log-rank P =0.34). Thrombophilia in recipients (odds ratio 0.55; confidence interval 0.06-2.29; P =0.56) or in donors (odds ratio 1.53; confidence interval 0.27-5.74; P =0.46) did not correlate with graft loss at 30 days after transplantation. In contrast to recent reports, this study did not demonstrate an association between thrombophilia and renal allograft loss, and routine screening is not recommended.

Fully differential cross sections for 3.6 MeV u(-1) AuZp++He collisions

Recent experimental data for fully differential cross sections have been compared to various continuum-distorted-wave eikonal-initial-state models without much success, despite good agreement with double-differential cross sections. A four-body model is formulated here and results are presented both when the internuclear potential is omitted and when it is included. They are compared with recent experimental data for fully differential cross sections for 3.6 MeV/u Au-P(Z)++He collisions, Z(P)=24,53.

Educating for peace? Citizenship education in Quebec and Northern Ireland

The article explores particularities of citizenship education in divided societies by comparing key concepts and theoretical frameworks underpinning citizenship education curricula in two divided societies, one of which could be described as relatively peaceful and the other as slowly emerging from political violence. A document analysis of the citizenship education curricula in both societies is conducted to compare differences and commonalities of attempts to promote citizenship and peaceful community relations. Conceptualizations of and interrelationships between citizenship, human rights, and peace education are explored in theory and curricular documents in both societies. The discussion reflects on the value of citizenship education in the context of community divisions and its possible impact on sustainable peace in divided societies.

Acoustic, volumetric, compressibility and refractivity properties and reduction parameters for the ERAS and Flory models of some homologous series of amines from 298.15 to 328.15 K

The speeds of sound u, densities ? and refractive indices nD of homologous series of mono-, di-, and tri-alkylamines were measured in the temperature range from 298.15 to 328.15 K. Isentropic and isothermal compressibilities ?S and ?T, molar refraction Rm, Eykman’s constant Cm, Rao’s molar sound function R, thermal expansion coefficient a, thermal pressure coefficient ?, and reduction parameters P*, V*, and T* in frameworks of the ERAS model for associated amines and Flory model for tertiary amines have been calculated from the measured experimental data. Applicability of the Rao theory and the ERAS and Flory models have been examined and discussed for the alkyl amines.