Effects of a selected motor skill task on the development of stereopsis

One would expect visual-perceptual abilities to be quite important in sport skills. Donna Mae Miller (1960) substantiated this idea when she examined a battery of eight tests she felt were important in responding quickly and accurately to visual cues. Highly skilled athletes scored considerably higher in areas of static balance, stereopsis, blocks response and mutilated words than did lower skilled athletes. Williams (1968) in a similar study looked at visu&l-perceptual judgments in a more dynamic approach. Subjects were asked to catch tennis balls after they had been projected into the air and bounced off of a canvas. The results found highly skilled performers significantly superior in visual perception to individuals classified as poorly skilled

Assessing the reactivity of sodium alkyl-magnesiates towards quinoxaline : single electron transfer (SET) vs. nucleophilic alkylation processes

By exploring the reactivity of sodium butyl-magnesiate (1) supported by the bulky chelating silyl(bisamido) ligand {Ph2Si(NAr*)2}(2-) (Ar* = 2,6-iPr2-C6H3) towards Quinoxaline (Qx), the ability of this bimetallic system to effectively promote SET processes has been disclosed. Thus 1 executes the single-electron reduction of Qx affording complex (2) whose structure in the solid state contains two quinaxolyl radical anions Qx˙ stabilised within a dimeric magnesiate framework. Combining multinuclear NMR and EPR measurements with DFT calculations, new insights into the constitution of 2 in solution and its magnetic behaviour have been gained. Further evidence on the SET reactivity of 1 was found when it was reacted with nitroxyl radical TEMPO which furnished contacted ion pair sodium magnesiate [(Ph2Si(NAr*)2)Mg(TEMPO(-))Na(THF)3] (4) where both metals are connected by an alkoxide bridge, resulting from reduction of TEMPO. The role that the different ligands present in 1 can play in these new SET reactions has also been assessed. Using an amination approach, the Bu group in 1 can be replaced by the more basic amide TMP allowing the isolation of (3) which was characterised by multinuclear NMR and X-ray crystallography. (1)H NMR monitoring of the reaction of 3 with Qx showed its conversion to 2, leaving the hydrogen atoms of the heterocycle untouched. Contrastingly, using sodium homoalkyl magnesiate [NaMg(CH2SiMe3)3] (5) led to the chemoselective C2 alkylation of this heterocycle, suggesting that the presence of the steric stabiliser {Ph2Si(NAr*)2}(2-) on the mixed-metal reagent is required in order to facilitate the Qx reduction

Sodium congener of the classical lithium methylchromate dimer: synthetic, x-ray crystallographic, and magnetic studies of Me8Cr2[Na(OEt2)](4)

One of the milestone structures in the development of transition-metal complexes with metal metal bonds of multiple bond order was the lithium methylchromate dimer Me8Cr2[Li(donor)](4) (donor = THF or Et2O). Using a simple salt metathesis reaction mixing this compound with sodium tert-butoxide, the sodium congener Me8Cr2-[Na(OEt2)]4 has been synthesized as a green crystalline compound and isolated in 51% yield. Its solid-state structure was determined by single-crystal X-ray diffraction. Exhibiting exact crystallographic C-4h symmetry, this heavier alkali-metal chromate structure is also dimeric, formally comprising a (Me8Cr4)(4-) tetranionic core with four peripheral Na+ cations carrying supporting ether ligands. Its salient feature is the long Cr center dot center dot center dot Cr distance of 3.263(2) angstrom, which is remarkably elongated compared to that in the lithium THF-solvated congener [1.968(2) angstrom]. With respect to the methyl C atoms, the Cr coordination is distorted-square-planar. Each Na interacts with four methyl C atoms, and there are also some short Na center dot center dot center dot H(C) contacts. Unlike for lithium chromate, no NMR spectroscopic data could be obtained for sodium chromate. The paramagnetic character of sodium chromate was confirmed by variable-temperature magnetization measurements, which indicated antiferromagnetic behavior

Competitive strategy in socially entrepreneurial nonprofit organizations: innovation and differentiation

Social entrepreneurship has attracted an increasing volume of research in an attempt to understand the basis of successful value creation aimed at solving social problems. In an effort to advance social entrepreneurship research beyond its current focus on conceptualizing the concept, this article addresses the role of innovation in achieving greater social impact. Using multiple theoretical case studies, this research finds that innovation-based competitive strategies of socially entrepreneurial nonprofit organizations substantially contribute to the achievement of social value. Innovation-based strategies are uniquely characterized by a primary focus on differentiation, with innovations directed at product, process, and system change levels. They tend to actively involve both externally and internally focused learning. Nonprofit organizations' innovation strategies are strongly influenced by their organizational characteristics, in particular the need to build sustainable organizations. The article concludes with implications for theory and practice and directions for further research