Effectiveness of Two Keyboarding Instructional Approaches on the Keyboarding Speed, Accuracy, and Technique of Elementary Students

Background: Keyboarding skill development is important for elementary students. Limited research exists to inform practice on effective keyboarding instruction methods. Method: Using a quasi-experimental design, we examined the effectiveness of Keyboarding Without Tears® (n = 786) in the experimental schools compared to the control schools who used the district standard instructional approach of free web-based activities (n = 953) on improving keyboarding skills (speed, accuracy, and technique) in elementary students. Results: The results showed significant improvements in keyboarding speed and accuracy in all schools for all grades favoring the experimental schools compared to the control schools. Significant differences in improvements in keyboarding technique were found with large effect sizes favoring the experimental schools for kindergarten to the second grade and small effect sizes favoring the control schools for the third to fifth grade. Conclusion: Professionals involved in assisting with keyboarding skill development in children are recommended to begin training in these skills in early elementary grades, especially to assist in proper keyboarding technique development. While using free web-based activities are beneficial to improving keyboarding speed and accuracy, as well as keyboarding technique, using a developmentally-based curriculum, such as Keyboarding Without Tears®, may further enhance improvements in the keyboarding skills of elementary students

Devolution and the economy : a Scottish perspective

In their interesting and challenging chapter John Adams and Peter Robinson assess the consequences for economic development policy of the devolution measures enacted by the UK Labour government post 1997. Their chapter ranges widely over current UK regional disparities, the link between devolution and economic growth, the balance of responsibilities in policy between Whitehall and the devolved administrations, and finally, they raise questions about the developing "quasi-federal" role of Whitehall in regulating or coordinating the new devolved policy landscape. In response, we propose to focus on four issues that we believe are key to understanding the economic consequences of devolution both at the Scottish and UK levels. First, we argue that the view of Scotland's devolutionary experience in economic policy is partial and so does not fully capture the nature and extent of change post 1999. Secondly, we examine the role of devolution in regional economic performance. There is much in their paper on this topic with which we agree but we contend that there are significant omissions in the analysis, which are important for policy choice. Our third section highlights an area not discussed in depth by Adams and Robinson's paper: the funding of the devolution settlement. Here we consider some of the implications of funding arrangements for economic performance and the options for a new funding settlement. Finally, we deal with the difficult issue of co-ordination between the centre and the devolved regions. We contend that co-ordination is largely conspicuous by its absence. Moreover, where coordination is deployed it reflects an inadequate understanding of the extent to which the economies of the regions and devolved territories of the UK are linked

Axionic dark energy and a composite QCD axion

We discuss the idea that the model-independent (MI) axion of string theory is the source of quintessential dark energy. The scenario is completed with a composite QCD axion from hidden sector squark condensation that could serve as dark matter candidate. The mechanism relies on the fact that the hidden sector anomaly contribution to the composite axion is much smaller than the QCD anomaly term. This intuitively surprising scenario is based on the fact that below the hidden sector scale $\Lambda_h$ there are many light hidden sector quarks. Simply, by counting engineering dimensions the hidden sector instanton potential can be made negligible compared to the QCD anomaly term.Comment: 9 pages, 7 figure

Viability of Various Ignition Sources to Ignite A2L Refrigerant Leaks

An international drive toward sustainability of refrigeration systems will require the adoption of low global warming potential (GWP) refrigerants. Most of these are mildly flammable. Low-GWP refrigerants are generally well characterized in terms of their lower flammability limits, heats of combustion, and flame speeds. However, they are poorly understood in terms of their susceptibility to ignition from sources commonly encountered in residential and industrial settings, including motors, electric arcs, hot surfaces, and open flames. This important gap in understanding is the focus of this project. The primary objective of this project was to perform tests to determine the viability of various ignition sources to ignite A2L refrigerants in air. Fifteen ignition sources were identified and tested. The A2L refrigerants tested were R-32, R-452B, R-1234yf, and R-1234ze. The tests were performed in a windowed stainless steel chamber with dimensions of 0.3 × 0.3 × 0.3 m and a volume of 27 L. Four of the ignition sources resulted in deflagrations or localized flames in the refrigerant-air mixtures. These were: hot wire (800 °C), safety match, lighter flame insertion, and leak impinging on candle, in order of decreasing ignition viability. Among the 15 potential ignition sources, it is remarkable that 11 were unable to ignite any of the mixtures considered here. These were: cigarette insertion, barbeque lighter, plug and receptacle, light switch, hand mixer, cordless drill, friction sparks, hair dryer, toaster, hot plate insertion, and space heater insertion. The inability of so many ignition sources to ignite A2L refrigerants is attributed here to the very long quenching distances of these refrigerants when mixed with air. Another remarkable finding is that these A2L refrigerants can act as either fuels or suppressants. For example, smoldering cigarettes were extinguished every time they encountered a stoichiometric mixture of A2L refrigerant and air

Giant magnetoelectric effect in pure manganite-manganite heterostructures

Obtaining strong magnetoelectric couplings in bulk materials and heterostructures is an ongoing challenge. We demonstrate that manganite heterostructures of the form ${\rm (Insulator)/(LaMnO_3)_n/(CaMnO_3)_n/(Insulator)}$ show strong multiferroicity in magnetic manganites where ferroelectric polarization is realized by charges leaking from ${\rm LaMnO_3}$ to ${\rm CaMnO_3}$ due to repulsion. Here, an effective nearest-neighbor electron-electron (electron-hole) repulsion (attraction) is generated by cooperative electron-phonon interaction. Double exchange, when a particle virtually hops to its unoccupied neighboring site and back, produces magnetic polarons that polarize antiferromagnetic regions. Thus a striking giant magnetoelectric effect ensues when an external electrical field enhances the electron leakage across the interface.Comment: 13 page

A surface electrode point Paul trap

We present a model as well as experimental results for a surface electrode radio-frequency Paul trap that has a circular electrode geometry well-suited for trapping of single ions and two-dimensional planar ion crystals. The trap design is compatible with microfabrication and offers a simple method by which the height of the trapped ions above the surface may be changed \emph{in situ}. We demonstrate trapping of single and few Sr+ ions over an ion height range of 200-1000 microns for several hours under Doppler laser cooling, and use these to characterize the trap, finding good agreement with our model.Comment: 10 pages, 11 figures, 1 tabl

Curvature suppresses the Rayleigh-Taylor instability

The dynamics of a thin liquid film on the underside of a curved cylindrical substrate is studied. The evolution of the liquid layer is investigated as the film thickness and the radius of curvature of the substrate are varied. A dimensionless parameter (a modified Bond number) that incorporates both geometric parameters, gravity, and surface tension is identified, and allows the observations to be classified according to three different flow regimes: stable films, films with transient growth of perturbations followed by decay, and unstable films. Experiments and theory confirm that, below a critical value of the Bond number, curvature of the substrate suppresses the Rayleigh-Taylor instability

Singlet superfield extension of the minimal supersymmetric standard model with Peccei-Quinn symmetry and a light pseudoscalar Higgs boson at the LHC

Motivated by the mu-problem and the axion solution to the strong CP-problem, we extend the MSSM with one more chiral singlet field $X_e$. The underlying PQ-symmetry allows only one more term $X_e H_u H_d$ in the superpotential. The spectrum of the Higgs system includes a light pseudoscalar $a_X$ (in addition to the standard CP-even Higgs boson), predominantly decaying to two photons: $a_X \to \gamma \gamma$. Both Higgs bosons might be in the range accessible to current LHC experiments.Comment: 5 pages with 3 figure