Source of Knowledge Dynamics-Transition from High School to University.

The paper addresses the dynamics of education by using Markov chains, a powerful probabilistic model able to make predictions on how sources of knowledge either change or stabilize over adulthood. To this end, each student filled in a survey that rated, on a scale from 1 to 5, the utility of five different sources of knowledge. They completed this survey twice, once for their previous and once for their current education.

BaCoO2.22: the most oxygen-deficient certified cubic perovskite.

The cubic BaCoO(∼2.2) was announced in the early 50's as the final product of high temperature self-reduction within the BaCoO(3-δ) series. However, apart from this report no clear characterization has been provided to date.

Mixed metallic Ba(Co,Fe)X(0.2)O(3-δ) (X = F, Cl) hexagonal perovskites: drastic effect of Fe-incorporation on structural and electronic features.

Starting from the parent 10H-Ba(5)Co(5)X(1-x)O(13-δ) (trimeric strings of face-sharing CoO(6) octahedra with terminal CoO(4) tetrahedra, stacking sequence (chhch')(2)) and 6H-Ba(6)Co(6)X(1-x)O(16-δ) (similar with tetrameric strings, stacking sequence chhhch') hexagonal perovskites forms (X = F, Cl; c, h = [BaO(3)] layers ; h' = [BaOX(1-y)] layers), we show here that the Fe incorporation leads to large domains of solid solutions for both X = F and Cl but exclusively stabilizes the 10H-form independently of the synthesis method. In this form, the lowest concentration of h-layers is stabilized by a sensitive metal reduction with increasing the Fe ratio. In a more general context of competition between several hexagonal perovskite polymorphs available for most of the transition metals, this redox change is most probably the key factor driving 1D (face-sharing chains) to 3D (corner-sharing) connectivities.

Ba8Co2Mn6ClO22, a quasi-1D hexagonal perovskite polytype containing new 8H-blocks.

In this communication we report the synthesis and full structural characterization of the new phase Ba(8)Co(2)Mn(6)ClO(22) formed of novel 8H-hexagonal perovskite blocks, a good example of the use of a multi-technique approach (combination of single crystal X-ray diffraction, micro-probe analysis and DFT calculations). Strikingly, the stabilization of original linear hexamers in the blocks is achieved by Mn/Co ordering in the octahedral and tetrahedral sites.

TSH and thyroxine in cord blood of subjects from an endemic area.

Thyroxine (T4) and TSH were assayed in the triplet: maternal venous blood at delivery (M), cord blood (C) and total capillary dry spot blood of the corresponding children 4 - 5 days postpartum (Nb). Fifty-four triplets in all (spontaneous deliveries, full term infants from the Cîmpulung endemic goiter area) were thus determined by sampling out the native families. The controls were 10 triplets from Bucharest, a non-endemic goiter area.