Charge ordering in charge-compensated Na0.41CoO2Na_{0.41}CoO_2 by oxonium ions

Charge ordering behavior is observed in the crystal prepared through the immersion of the $Na_{0.41}CoO_2$ crystal in distilled water. Discovery of the charge ordering in the crystal with Na content less than 0.5 indicates that the immersion in water brings about the reduction of the $Na_{0.41}CoO_2$. The formal valence of Co changes from +3.59 estimated from the Na content to +3.5, the same as that in $Na_{0.5}CoO_2$. The charge compensation is confirmed to arise from the intercalation of the oxonium ions as occurred in the superconducting sodium cobalt oxide bilayer-hydrate.\cite{takada1} The charge ordering is the same as that observed in $Na_{0.5}CoO_2$. It suggests that the Co valence of +3.5 is necessary for the charge ordering.Comment: 5 pages, 4 figure

The Impact of a School-Based Weight Management Program Involving Parents via mHealth for Overweight and Obese Children and Adolescents with Intellectual Disability: A Randomized Controlled Trial

There is a scarcity of resources and studies that utilize targeted weight management interventions to engage parents via mHealth tools targeting obese children and adolescents with mild intellectual disabilities (MIDs) extended from school to a home setting. To test the feasibility and acceptability of a school-based weight program (SBWMP) involving parents via mHealth tools designed to reduce weight, enhance knowledge and adopt healthy lifestyles, and thereby achieve better psychosocial well-being among children and adolescents with MIDs. Four special schools were randomly assigned as intervention or control schools. Students from the intervention group (n = 63) were compared to those in the control group (n = 52), which comprised those with usual school planned activities and no parental involvement. Demographics were considered as covariates in a general linear model, an ordinal regression model and a binary logistic regression model analyzing the relationships between the SBWMP and the outcome variables at baseline (T0) and six months later (T1). Body weight, body mass index, and triceps and subscapular skinfold thickness were lower in the intervention group compared to the control group, although the differences were not statistically significant. There was a positive and direct impact of the SBWMP on students’ health knowledge and psychological impacts in the intervention group. The SBWMP extended to the home involving parents via mHealth tools is a feasible and acceptable program for this group with MIDs and their parents

The Structure of TGBC_C Phases

We study the transition from the cholesteric phase to two TGB$_C$ phases near the upper critical twist $k_{c2}$: the Renn-Lubensky TGB$_C$ phase, with layer normal rotating in a plane perpendicular to the pitch axis, and the Bordeaux TGB$_C$ phase, with the layer normal rotating on a cone parallel to the pitch axis. We calculate properties, including order-parameter profiles, of both phases.Comment: 4 pages, 4 figures, Submitted to Physical Review E, Rapid Communications, September 5, 2003; Revised manuscript (to the paper submitted on March 18, 2003, cond-mat/0303365)that includes an important missing reference and presents an improved analysis of a generalized mode

Grain refinement in a AlZnMgCuTi alloy by intensive melt shearing: A multi-step nucleation mechanism

This is a post-print version of the article. Copyright @ 2010 Elsevier B.V.Direct chill (DC) cast ingots of wrought Al alloys conventionally require the deliberate addition of a grain refiner to provide a uniform as-cast microstructure for the optimisation of both mechanical properties and processability. Grain refiner additions have been in widespread industrial use for more than half a century. Intensive melt shearing can provide grain refinement without the need for a specific grain refiner addition for both magnesium and aluminium based alloys. In this paper we present experimental evidence of the grain refinement in an experimental wrought aluminium alloy achieved by intensive melt shearing in the liquid state prior to solidification. The mechanisms for high shear induced grain refinement are correlated with the evolution of oxides in alloys. The oxides present in liquid aluminium alloys, normally as oxide films and clusters, can be effectively dispersed by intensive shearing and then provide effective sites for the heterogeneous nucleation of Al3Ti phase. As a result, Al3Ti particles with a narrow size distribution and hence improved efficiency as active nucleation sites of alpha-aluminium grains are responsible for the achieved significant grain refinement. This is termed a multi-step nucleation mechanism.Funding was obtained from the EPRSC

Two-band second moment model and an interatomic potential for caesium

A semi-empirical formalism is presented for deriving interatomic potentials for materials such as caesium or cerium which exhibit volume collapse phase transitions. It is based on the Finnis-Sinclair second moment tight binding approach, but incorporates two independent bands on each atom. The potential is cast in a form suitable for large-scale molecular dynamics, the computational cost being the evaluation of short ranged pair potentials. Parameters for a model potential for caesium are derived and tested

Isovector and isoscalar superfluid phases in rotating nuclei

The subtle interplay between the two nuclear superfluids, isovector T=1 and isoscalar T=0 phases, are investigated in an exactly soluble model. It is shown that T=1 and T=0 pair-modes decouple in the exact calculations with the T=1 pair-energy being independent of the T=0 pair-strength and vice-versa. In the rotating-field, the isoscalar correlations remain constant in contrast to the well known quenching of isovector pairing. An increase of the isoscalar (J=1, T=0) pair-field results in a delay of the bandcrossing frequency. This behaviour is shown to be present only near the N=Z line and its experimental confirmation would imply a strong signature for isoscalar pairing collectivity. The solutions of the exact model are also discussed in the Hartree-Fock-Bogoliubov approximation.Comment: 5 pages, 4 figures, submitted to PR

Putting theory oriented evaluation into practice

Evaluations of gaming simulations and business games as teaching devices are typically end-state driven. This emphasis fails to detect how the simulation being evaluated does or does not bring about its desired consequences. This paper advances the use of a logic model approach which possesses a holistic perspective that aims at including all elements associated with the situation created by a game. The use of the logic model approach is illustrated as applied to Simgame, a board game created for secondary school level business education in six European Union countries

Greybody Factors for Rotating Black Holes on Codimension-2 Branes

We study the absorption probability and Hawking radiation of the scalar field in the rotating black holes on codimension-2 branes. We find that finite brane tension modifies the standard results in Hawking radiation if compared with the case when brane tension is completely negligible. We observe that the rotation of the black hole brings richer physics. Nonzero angular momentum triggers the super-radiance which becomes stronger when the angular momentum increases. We also find that rotations along different angles influence the result in absorption probability and Hawking radiation. Compared with the black hole rotating orthogonal to the brane, in the background that black hole spins on the brane, its angular momentum brings less super-radiance effect and the brane tension increases the range of frequency to accommodate super-radiance. These information can help us know more about the rotating codimension-2 black holes.Comment: 16 pages, 7 figures, minor modification, accepted for publication in JHE

Influence of a Brane Tension on Phantom and Massive Scalar Field Emission

We elaborate the signature of the extra dimensions and brane tension in the process of phantom and massive scalar emission in the spacetime of (4+n)-dimensional tense brane black hole. Absorption cross section, luminosity of Hawking radiation and cross section in the low-energy approximation were found. We envisage that parameter connected with the existence of a brane imprints its role in the Hawking radiation of the considered fields.Comment: 7 pages, * figures, RevTex, to be published in General Relativity and Gravitatio