906 research outputs found

    Creative thinking in prospective teachers: the 'status quo' and the impact of contextual factors

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    To create unique and appropriate learning opportunities and environments and to nurture the development of creative thinking abilities among learners are some of the demands for creative thinking currently expected of teachers globally and also in South Africa. Creative thinking in academic context assumes, among other things, the ability to generate a variety of original ideas, to see different viewpoints and elaborate on ideas. We report on the findings of a quantitative pilot investigation by means of experimental research utilizing an ex post facto design to determine the status quo regarding the creative thinking abilities of a hetrogeneous group of 207 pre-service teachers studying at a South African university, using the Abbreviated Torrance Test for Adults (ATTA) and a Partial Least Squares (PLS) exploration into the relationship between contextual factors and the students’ creative thinking abilities. Strong correlations were found among a variety of contextual factors such as the type of school model and culture and creative thinking abilities and also between specific contextual factors such as the choice of role model and socio economic and acculturation factors and certain creative thinking abilities. This research explores a largely unknown field, namely, the creative thinking abilities of a group of South African pre-service teachers of different cultural groups and creates an awareness of the need for the development of creative thinking abilities among these prospective teachers.Keywords: contextual factors; creativity and culture, creativity; creative thinking; creative thinking abilities; teacher trainin

    The largest white light flare ever observed: 25 April 1984, 0001 UT

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    The X13/3B flare of 25 April 1984, 0001 UT, was accompanied by intense white light emission that reached a peak power output approx 2x10 to the 29 erg/sec in the optical/near UV continuum; the total energy radiated in the continuum alone reached 10 to the 32 power ergs. This was the most powerful white light flare yet recorded, exceeding the peak output of the largest previously known event by more than one order of magnitude. The flare was a two-ribbon type with intense embedded kernels as observed in both Balmer-alpha line and Balmer continuum, and each of these flare ribbons covered separate umbrae shortly after the maximum of the event. The onset and peak of the white light emission coincided with the onset and peak of the associated E greater than 100 KeV hard X-ray burst, while the 1-8 angstrom soft X-ray emission reached its maximum 4 minutes after the peak in white light

    Empirical ground-motion prediction equations for Northwestern Turkey using the aftershocks of the 1999 Kocaeli earthquake

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    We present ground motion models for northwestern Turkey using the aftershocks of the Mw 7.4, 1999 Kocaeli earthquake. We consider 4047 velocity and acceleration records for each component of motion, from 528 earthquakes recorded by stations belonging to regional networks. The ground motion models obtained provide peak ground velocity, peak ground acceleration, and spectral accelerations for 8 different frequencies between 1 and 10 Hz. The analysis of the error distribution shows that the record-to-record component of variance is the largest contribution to the standard deviation of the calibrated ground- motion models. Furthermore, a clear dependence of inter-event error on stress drop is observed. The empirical ground-motion prediction equations, derived for both the larger horizontal and vertical components, are valid in the local magnitude range from 0.5 to 5.9, and for hypocentral distances up to 190 km. Citation: Bindi, D., S. Parolai, H. Grosser, C. Milkereit, and E. Durukal (2007), Empirical ground-motion prediction equations for northwestern Turkey using the aftershocks of the 1999 Kocaeli earthquake

    Source parameters and seismic moment-magnitude scaling for Northwestern Turkey

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    Abstract The source parameters of 523 aftershocks (0.5 ML 5.9) of the 1999 Kocaeli earthquake are determined by performing a two-step spectral fitting procedure. The source spectrum, corrected for both site and propagation effects, is described in terms of a standard x-square model multiplied by an exponential term of frequency. The latter term is introduced to estimate the high-frequency (f 12 Hz) fall-off of the acceleration source spectra by computing the j parameter. The seismic moments obtained range between 1.05 1014 and 2.41 1017 N m, whereas the Brune stress drops are between 0.002 and 40 MPa. The j value varies between 0.00 and 0.08 sec, indicating a decay of the acceleration level at the higher frequency part of the spectrum greater than that assumed by the x 2 model. Both the stress drop and the j parameter show the tendency of increasing with aftershock magnitude. No evidence of self-similarity breakdown is observed between the source radius and M0. Finally, both the seismic moment and the moment magnitude are compared with the local magnitude to derive new moment–magnitude relationships for the area

    Regularity properties of distributions through sequences of functions

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    We give necessary and sufficient criteria for a distribution to be smooth or uniformly H\"{o}lder continuous in terms of approximation sequences by smooth functions; in particular, in terms of those arising as regularizations (Tϕn)(T\ast\phi_{n}).Comment: 10 page

    On the completeness of impulsive gravitational wave space-times

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    We consider a class of impulsive gravitational wave space-times, which generalize impulsive pp-waves. They are of the form M=N×R12M=N\times\mathbb{R}^2_1, where (N,h)(N,h) is a Riemannian manifold of arbitrary dimension and MM carries the line element ds2=dh2+2dudv+f(x)δ(u)du2ds^2=dh^2+ 2dudv+f(x)\delta(u)du^2 with dh2dh^2 the line element of NN and δ\delta the Dirac measure. We prove a completeness result for such space-times MM with complete Riemannian part NN.Comment: 13 pages, minor changes suggested by the referee

    On the Geroch-Traschen class of metrics

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    We compare two approaches to semi-Riemannian metrics of low regularity. The maximally 'reasonable' distributional setting of Geroch and Traschen is shown to be consistently contained in the more general setting of nonlinear distributional geometry in the sense of Colombea

    Classes of generalized functions with finite type regularities

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    We introduce and analyze spaces and algebras of generalized functions which correspond to Hölder, Zygmund, and Sobolev spaces of functions. The main scope of the paper is the characterization of the regularity of distributions that are embedded into the corresponding space or algebra of generalized functions with finite type regularities

    Profiling COVID-19 Genetic Research: A Data-Driven Study Utilizing Intelligent Bibliometrics

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    The COVID-19 pandemic constitutes an ongoing worldwide threat to human society and has caused massive impacts on global public health, the economy and the political landscape. The key to gaining control of the disease lies in understanding the genetics of SARS-CoV-2 and the disease spectrum that follows infection. This study leverages traditional and intelligent bibliometric methods to conduct a multi-dimensional analysis on 5,632 COVID-19 genetic research papers, revealing that 1) the key players include research institutions from the United States, China, Britain and Canada; 2) research topics predominantly focus on virus infection mechanisms, virus testing, gene expression related to the immune reactions and patient clinical manifestation; 3) studies originated from the comparison of SARS-CoV-2 to previous human coronaviruses, following which research directions diverge into the analysis of virus molecular structure and genetics, the human immune response, vaccine development and gene expression related to immune responses; and 4) genes that are frequently highlighted include ACE2, IL6, TMPRSS2, and TNF. Emerging genes to the COVID-19 consist of FURIN, CXCL10, OAS1, OAS2, OAS3, and ISG15. This study demonstrates that our suite of novel bibliometric tools could help biomedical researchers follow this rapidly growing field and provide substantial evidence for policymakers' decision-making on science policy and public health administration
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