1,381 research outputs found

    Fostering Student Agency to Build a Whole Child, Whole School, Whole Community Approach

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    In this practitioner perspective, we explore the concept of student agency through the implementation of a student government association in a laboratory middle school. Interviews with a social studies teacher and her students offer perspectives of the impact of student voice and choice for student experiences. We describe three major lessons learned through this implementation process: students learn to have healthy conflict and cooperative skills; students learn the appropriate processes to enact change in a democratic society; and students learn to conduct service for their peers, school, and community

    Controlling the stability transfer between oppositely traveling waves and standing waves by inversion-symmetry-breaking perturbations

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    The effect of an externally applied flow on symmetry degenerated waves propagating into opposite directions and standing waves that exchange stability with the traveling waves via mixed states is analyzed. Wave structures that consist of spiral vortices in the counter rotating Taylor-Couette system are investigated by full numerical simulations and explained quantitatively by amplitude equations containing quintic coupling terms. The latter are appropriate to describe the influence of inversion symmetry breaking perturbations on many oscillatory instabilities with O(2) symmetry.Comment: 4 pages, 4 figure

    Analysis of some global optimization algorithms for space trajectory design

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    In this paper, we analyze the performance of some global search algorithms on a number of space trajectory design problems. A rigorous testing procedure is introduced to measure the ability of an algorithm to identify the set of ²-optimal solutions. From the analysis of the test results, a novel algorithm is derived. The development of the novel algorithm starts from the redefinition of some evolutionary heuristics in the form of a discrete dynamical system. The convergence properties of this discrete dynamical system are used to derive a hybrid evolutionary algorithm that displays very good performance on the particular class of problems presented in this paper

    Reactivity of (1-methoxycarbonylpentadienyl)iron(1+) cations with hydride, methyl, and nitrogen nucleophiles

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    The reaction of tricarbonyl and (dicarbonyl)triphenylphosphine (1-methoxycarbonyl-pentadientyl)iron(1+) cations 7 and 8 with methyl lithium, NaBH3CN, or potassium phthalimide affords (pentenediyl)iron complexes 9a-c and 11a-b, while reaction with dimethylcuprate, gave (E,Z-diene)iron complexes 10 and 12. Oxidatively induced-reductive elimination of 9a-c gave vinylcyclopropanecarboxylates 17a-c. The optically active vinylcyclopropane (+)-17a, prepared from (1S)-7, undergoes olefin cross-metathesis with excess (+)-18 to yield (+)-19, a C9C16 synthon for the antifungal agent ambruticin. Alternatively reaction of 7 with methanesulfonamide or trimethylsilylazide gave (E,E-diene)iron complexes 14d and e. Huisgen [3 + 2] cyclization of the (azidodienyl)iron complex 14e with alkynes afforded triazoles 25a-e

    Competition between normal and intruder states inside the "Island of Inversion"

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    The beta decay of the exotic 30Ne (N=20) is reported. For the first time, the low-energy level structure of the N=19, 30Na (Tz = 4), is obtained from beta-delayed gamma spectroscopy using fragment-beta-gamma-gamma coincidences. The level structure clearly displays "inversion", i.e., intruder states with mainly 2p2h configurations displacing the normal states to higher excitation energies. The good agreement in excitation energies and the weak and electromagnetic decay patterns with Monte Carlo Shell Model calculations with the SDPF-M interaction in the sdpf valence space illustrates the small d3/2 - f7/2 shell gap. The relative position of the "normal dominant" and "intruder dominant" excited states provides valuable information to understand better the N=20 shell gap.Comment: 4 pages, 5 figure

    Nerve Terminal Degeneration Is Independent of Muscle Fiber Genotype in SOD1G93A Mice

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    Background: Motor neuron degeneration in SOD1 G93A transgenic mice begins at the nerve terminal. Here we examine whether this degeneration depends on expression of mutant SOD1 in muscle fibers. Methodology/Principal Findings: Hindlimb muscles were transplanted between wild-type and SOD1 G93A transgenic mice and the innervation status of neuromuscular junctions (NMJs) was examined after 2 months. The results showed that muscles from SOD1 G93A mice did not induce motor terminal degeneration in wildtype mice and that muscles from wildtype mice did not prevent degeneration in SOD1 G93A transgenic mice. Control studies demonstrated that muscles transplanted from SOD1 G93A mice continued to express mutant SOD1 protein. Experiments on wildtype mice established that the host supplied terminal Schwann cells (TSCs) at the NMJs of transplanted muscles. Conclusions/Significance: These results indicate that expression of the mutant protein in muscle is not needed to cause motor terminal degeneration in SOD1 G93A transgenic mice and that a combination of motor terminals, motor axons and Schwann cells, all of which express mutant protein may be sufficient
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