Selected National Trends in Educational Administration

In the decade ahead, who will determine and teach the skills necessary for the administration of public education? What will be the future of school boards? These are two of the major questions this author sees as confronting teachers of educational administration if present trends continue

Models of Reflective Thinking

The complexity of educating children requires educators who are knowledgeable, skillful and flexible. Reflection augments the repertoire and flexibility of educators. However, not all practitioners function at the same level of reflection

An Editorial Statement

Will Rogers, the famous American humanist and social critic, once said, the schools are not as good as they used to be and they never were

Summing Up

This edition of Educational Considerations focuses on the principalship

Muon Simulations for Super-Kamiokande, KamLAND and CHOOZ

Muon backgrounds at Super-Kamiokande, KamLAND and CHOOZ are calculated using MUSIC. A modified version of the Gaisser sea level muon distribution and a well-tested Monte Carlo integration method are introduced. Average muon energy, flux and rate are tabulated. Plots of average energy and angular distributions are given. Implications on muon tracker design for future experiments are discussed.Comment: Revtex4 33 pages, 16 figures and 4 table

Cytochrome c550 in the cyanobacterium Thermosynechococcus elongatus: Study of redox mutants

Cytochrome c550 is one of the extrinsic Photosystem II subunits in cyanobacteria and red algae. To study the possible role of the heme of the cytochrome c550 we constructed two mutants of Thermosynechococcus elongatus in which the residue His-92, the sixth ligand of the heme, was replaced by a Met or a Cys in order to modify the redox properties of the heme. The H92M and H92C mutations changed the midpoint redox potential of the heme in the isolated cytochrome by +125 mV and –30 mV, respectively, compared with the wild type. The binding-induced increase of the redox potential observed in the wild type and the H92C mutant was absent in the H92M mutant. Both modified cytochromes were more easily detachable from the Photosystem II compared with the wild type. The Photosystem II activity in cells was not modified by the mutations suggesting that the redox potential of the cytochrome c550 is not important for Photosystem II activity under normal growth conditions. A mutant lacking the cytochrome c550 was also constructed. It showed a lowered affinity for Cl– and Ca2+ as reported earlier for the cytochrome c550-less Synechocystis 6803 mutant, but it showed a shorter lived Formula state, rather than a stabilized S2 state and rapid deactivation of the enzyme in the dark, which were characteristic of the Synechocystis mutant. It is suggested that the latter effects may be caused by loss (or weaker binding) of the other extrinsic proteins rather than a direct effect of the absence of the cytochrome c55

Synthesis and characterization of binuclear tantalum hydride complexes

Reduction of the quadruply-bridged (2Cl, 2H) tantalum(IV) dimer, Ta2Cl6 (PMe3)4H2 (2) with sodium amalgam in glyme or THF at 0[deg]C provides deep green Ta2Cl4(PMe3)4H2 (3) in 70% yield. Dimer 3 has a D2d Ta2Cl4(PMe3)4 substructure which closely resembles that of the quadruply metal-metal-bonded dimer W2Cl4(PMe3)4. The hydride ligands of 3 are located on a diagonal plane, bridging the two tantalum atoms and the Ta-Ta separation is 2.545(1) A. 3 reacts cleanly with Cl2, HCl and H2 in diethyl ether to provide the quadruply-bridged dimers 2, Ta2Cl5(PMe3)4H3 (4), and Ta2Cl4(PMe3)4H4 (5), respectively, in high yield. Dimer 5 can also be prepared in high yield via thermolysis of the tantalum(IV) hydride TaCl2H2(PMe3)4 (6) in refluxing methylcyclohexane. The X-ray structure of 5 shows that the ([mu]-H)4 group is staggered by 45[deg] with respect to the eclipsed pyramidal TaCl2(PMe3)2 end groups. The molecular symmetry of 5 is D2d and the Ta-Ta separation is 2.511(2)A. Multiple-scattering X[alpha] calculations on the model compounds Ta2Cl4(PH3)4H2 and Ta2Cl4(PH3)4 are used to elucidate the ground-state electronic structures of 3 and 5, and to probe the question of ([mu]-H)x rotation about the metal-metal bonds in these complexes. Crystal data (at 160[deg]C) are as follows: for 3, monoclinic space group C2/c, a = 18.371(5) A, b = 9.520(3) A, c = 18.942(6) A, [beta] = 125.36(2)[deg], V = 2701.8 A3, Z = 4,dcalc. = 1.991 g cm-3; for 5, tetragonal space group P4/nbm, a = b = 12.579(2) A, c = 10.205(2) A, V = 1614.7 A3, Z = 2, dcalc. = 1.670 g cm-3.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26987/1/0000554.pd

How STRANGE are your study animals?

A new framework for studies of animal behaviour will help to avoid sampling bias— ten years on from the call to widen the pool of human participants in psychology research beyond the WEIRD.Publisher PDFNon peer reviewe