7,348 research outputs found

    The importance of collegiality and reciprocal learning in the professional development of beginning teachers

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    This paper discusses factors which enhance induction experiences for beginning teachers. It reports the findings from case studies which explore the impact of new entrants to the teaching profession in Scotland. The data suggest that the most supportive induction processes mix both formal and informal elements, but that the informal elements such as collegiality, good communication and a welcoming workplace environment should not be underestimated. The study also highlights the potential benefits of a more collegiate environment for teachers across the career phases. Experienced teachers and new entrants had a range of experience to offer each other, thus creating more cohesive professional working which was supportive of early career teachers while encouraging reflection on practice among the more experienced professionals

    Weak Magnetism in Two Neutrino Double Beta Decay

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    We have extended the formalism for the two-neutrino double beta decay by including the weak-magnetism term, as well as other second-forbidden corrections. The weak magnetism diminishes the calculated half-lives in 10\sim 10%, independently of the nuclear structure. Numerical computations were performed within the pn-QRPA, for 76Ge^{76}Ge, 82Se^{82}Se, 100Mo^{100} Mo, 128Te^{128}Te and 130Te^{130}Te nuclei. No one of the second-forbidden corrections modifies significantly the spectrum shapes. The total reduction in the calculated half lives varies from 6% up to 32%, and strongly depend on the nuclear interaction in the particle-particle S=1,T=0S=1,T=0 channel. We conclude that the higher order effects in the weak Hamiltonian would hardly be observed in the two-neutrino double beta experiments.Comment: 8 pages, latex, 1ps figure, to appear in Phys. Lett.

    Spectral Signatures of the Diffusional Anomaly in Water

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    Analysis of power spectrum profiles for various tagged particle quantities in bulk SPC/E water is used to demonstrate that variations in mobility associated with the diffusional anomaly are mirrored in the exponent of the \onebyf\ region. Monitoring of \onebyf behaviour is shown to be a simple and direct method for linking phenomena on three distinctive length and time scales: the local molecular environment, hydrogen bond network reorganisations and the diffusivity. The results indicate that experimental studies of supercooled water to probe the density dependence of 1/fα1/f^\alpha spectral features, or equivalent stretched exponential behaviour in time-correlation functions, will be of interest.Comment: 5 Pages, 4 Figure

    Achievement goals, self-handicapping, and performance: A 2 × 2 achievement goal perspective

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    Elliot and colleagues (2006) examined the effects of experimentally induced achievement goals, proposed by the trichotomous model, on self-handicapping and performance in physical education. Our study replicated and extended the work of Elliot et al. by experimentally promoting all four goals proposed by the 262 model (Elliot & McGregor, 2001), measuring the participants’ own situational achievement goals, using a relatively novel task, and testing the participants in a group setting. We used a randomized experimental design with four conditions that aimed to induce one of the four goals advanced by the 262 model. The participants (n¼138) were undergraduates who engaged in a dart-throwing task. The results pertaining to self-handicapping partly replicated Elliot and colleagues’ findings by showing that experimentally promoted performance-avoidance goals resulted in less practice. In contrast, the promotion of mastery-avoidance goals did not result in less practice compared with either of the approach goals. Dart-throwing performance did not differ among the four goal conditions. Personal achievement goals did not moderate the effects of experimentally induced goals on selfhandicapping and performance. The extent to which mastery-avoidance goals are maladaptive is discussed, as well as the interplay between personal and experimentally induced goals

    Systematic and Causal Corrections to the Coherent Potential Approximation

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    The Dynamical Cluster Approximation (DCA) is modified to include disorder. The DCA incorporates non-local corrections to local approximations such as the Coherent Potential Approximation (CPA) by mapping the lattice problem with disorder, and in the thermodynamic limit, to a self-consistently embedded finite-sized cluster problem. It satisfies all of the characteristics of a successful cluster approximation. It is causal, preserves the point-group and translational symmetry of the original lattice, recovers the CPA when the cluster size equals one, and becomes exact as NcN_c\to\infty. We use the DCA to study the Anderson model with binary diagonal disorder. It restores sharp features and band tailing in the density of states which reflect correlations in the local environment of each site. While the DCA does not describe the localization transition, it does describe precursor effects of localization.Comment: 11 pages, LaTeX, and 11 PS figures, to appear in Phys. Rev. B. Revised version with typos corrected and references adde

    Intercontinental transport of pollution manifested in the variability and seasonal trend of springtime O3 at northern middle and high latitudes

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    Observations (0–8 km) from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment are analyzed to examine air masses contributing to the observed variability of springtime O3 and its seasonal increase at 40°–85°N over North America. Factor analysis using the positive matrix factorization and principal component analysis methods is applied to the data set with 14 chemical tracers (O3, NOy, PAN, CO, CH4, C2H2, C3H8, CH3Cl, CH3Br, C2Cl4, CFC-11, HCFC-141B, Halon-1211, and 7Be) and one dynamic tracer (potential temperature). Our analysis results are biased by the measurements at 5–8 km (70% of the data) due to the availability of 7Be measurements. The identified tracer characteristics for seven factors are generally consistent with the geographical origins derived from their 10 day back trajectories. Stratospherically influenced air accounts for 14 ppbv (35–40%) of the observed O3 variability for data with O3concentrations \u3c100 ppbv at middle and high latitudes. It accounts for about 2.5 ppbv/month (40%) of the seasonal O3 trend at midlatitudes but for only 0.8 ppbv/month (\u3c20%) at high latitudes, likely reflecting more vigorous midlatitude dynamical systems in spring. At midlatitudes, reactive nitrogen-rich air masses transported through Asia are much more significant (11 ppbv in variability and 3.5 ppbv/month in trend) than other tropospheric contributors. At high latitudes the O3 variability is significantly influenced by air masses transported from lower latitudes (11 ppbv), which are poor in reactive nitrogen. The O3 trend, in contrast, is largely defined by air masses rich in reactive nitrogen transported through Asia and Europe across the Pacific or the Arctic (3 ppbv/month). The influence from the stratospheric source is more apparent at 6–8 km, while the effect of O3 production and transport within the troposphere is more apparent at lower altitudes. The overall effect of tropospheric photochemical production, through long-range transport, on the observed O3 variability and its seasonal trend is more important at high latitudes relative to more photochemically active midlatitudes

    Charged Majoron Emission in Neutrinoless Double Beta Decay

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    We examine in detail the predictions of the charged majoron model, introduced recently by Burgess and Cline, for 0+ --> 0+ double beta decay transitions. The relevant nuclear matrix elements are evaluated, within the quasiparticle random phase approximation, for 76Ge, 82Se, 100Mo, 128Te and 150Nd nuclei. The calculated transition rates turn out to be much smaller than the experimental upper limits on possible majoron emission, except in a small region of the model's parameter space.Comment: 9 pages, 1 encapsulated postscript figure, uses epsf.tex; reference [15] has been correcte

    Performance of a repetitive task by aged rats leads to median neuropathy and spinal cord inflammation with associated sensorimotor declines

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    Epidemiological studies have demonstrated a relationship between advancing age and susceptibility to risk factors for median neuropathies and musculoskeletal disorders. In this study, we determined if performance of a voluntary reaching task by aged rats induced sensorimotor declines, median nerve dysfunction and increased inflammatory cytokines in peripheral nerves, muscle and spinal cord neurons. Aged (14 mon) rats were trained for 15 min/day for 4 weeks to learn a high repetition, low force (HRLF) task (19 reaches/min; 15% maximum pulling force). Aged task rats performed the task for 2 h/day, 3 days/wk, for 12 weeks (until they were 18 mon of age). No behavioral changes were detected in normal controls (NC) or food-restricted controls (FR C) as they aged. However, grip strength declined in HRLF rats in weeks 6-12 (P\u3c0.01 each) and 12-week trained-only rats (TR; P\u3c0.05), compared to NC. Mechanical hypersensitivity was present in weeks 9 and 12 HRLF reach limb forepaws (P\u3c0.01 and P\u3c0.05, respectively), and 12-week HRLF support limb forepaws (P\u3c0.01) and hindpaws (P=0.03), compared to NC. By week 12, median nerve conduction velocity declined 23%, bilaterally, in HRLF (P\u3c0.001 each), and 13% in TR (P\u3c0.05), compared to NC. Tumor necrosis factor alpha (TNFα) increased in 12-week HRLF muscle (P=0.005), median nerve (P\u3c0.01), and neurons in superficial lamina of HRLF cervical spinal cords (P\u3c0.01), compared to NC. interleukin 1 beta (IL1β) also increased in superficial lamina neurons (P\u3c0.01). Loss of grip strength was correlated with median nerve conduction slowing (r=0.70) as well as increased nerve and muscle TNFα (r=-0.38 and r=-0.41, respectively); decrease in forepaw withdrawal thresholds was correlated with median nerve conduction slowing (r=0.81), increased nerve TNFα (r=-0.59), and increased TNFα and IL1β in neurons in spinal cord dorsal horns (r=-0.52 and r=-0.47, respectively). Thus, aged rats performing a repetitive task exhibited sensorimotor declines that were associated with decreased median nerve conduction, and increased pro-inflammatory cytokines in the median nerve and cervical spinal cord neurons
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