2,459 research outputs found
Auditing the TPACK confidence of Australian pre-service teachers: the TPACK confidence survey (TCS)
This chapter describes the construction and validation of an instrument to measure teachersâ Technological Pedagogical Content Knowledge (TPACK). The TPACK Confidence Survey (TCS) contains scales that measure teachersâ attitudes toward using ICT; confidence to use ICT for teaching and learning tasks (TPACK); competency with ICT; Technology Knowledge (TK); and TPACK Vocational Self-efficacy. The scale measuring TPACK confidence uses the Learning With ICTs: Measuring ICT Use in the Curriculum instrument that has been evaluated and reported previously. This paper proposes that the TCS provides a valid and reliable instrument with which to audit teachersâ TPACK confidence
Phase synchrony facilitates binding and segmentation of natural images in a coupled neural oscillator network
Synchronization has been suggested as a mechanism of binding distributed feature representations facilitating segmentation of visual stimuli. Here we investigate this concept based on unsupervised learning using natural visual stimuli. We simulate dual-variable neural oscillators with separate activation and phase variables. The binding of a set of neurons is coded by synchronized phase variables. The network of tangential synchronizing connections learned from the induced activations exhibits small-world properties and allows binding even over larger distances. We evaluate the resulting dynamic phase maps using segmentation masks labeled by human experts. Our simulation results show a continuously increasing phase synchrony between neurons within the labeled segmentation masks. The evaluation of the network dynamics shows that the synchrony between network nodes establishes a relational coding of the natural image inputs. This demonstrates that the concept of binding by synchrony is applicable in the context of unsupervised learning using natural visual stimuli
Measuring the use of information and communication technologies (ICTs) in the classroom
In 2003, the ICT Curriculum Integration Performance Measurement Instrument was developed from an extensive review of the contemporary international and Australian research pertaining to the definition and measurement of ICT curriculum integration in classrooms (Proctor, Watson, & Finger, 2003). The 45-item instrument that resulted was based on theories and methodologies identified by the literature review. This paper describes psychometric results from a large-scale evaluation of the instrument subsequently conducted, as recommended by Proctor, Watson and Finger (2003). The resultant 20-item, two-factor instrument, now called Learning With ICTs: Measuring ICT Use in the Curriculum is both statistically and theoretically robust. This paper should be read in association with the original paper published in Computers in the Schools (Proctor, Watson & Finger, 2003) that described in detail the theoretical framework underpinning the development of the instrument
Chandra localization of XTE J1906+090 and discovery of its optical and infrared counterparts
We present the Chandra identification and localization of the transient X-ray source XTE J1906+090 and the discovery of its optical and infrared counterparts. Our analysis of archival Chandra ACIS-I observations of the field found the source approximately 8 away from the position determined earlier with the RXTE PCA. We have confirmed the source identification with timing analysis of the X-ray data, which detected the source spin period of 89.6 s. The best Chandra position for the source is R.A. = 19h04m47491, decl. = +09024140. Subsequently, we performed optical observations of the field around the new location and discovered a coincident optical source with R-band magnitude of 18.7. A search in the Two Micron All Sky Survey catalog revealed an infrared point source with J = 15.2, H = 14.2, and K = 13.5, whose location is also coincident with our Chandra and optical positions. Our results add fresh evidence for a Be/X-ray transient nature for XTE J1906+090
RXTE Observations of Soft Gamma Repeater Bursts
The spectra of short soft gamma repeater (SGR) bursts at photon energies above 15 keV are often well described by an optically thin thermal bremsstrahlung model (i.e., F(E) ~ E^â1 exp(âE/kT) ) with kT=20â40 keV. However, the spectral shape burst continuum at lower photon energies (down to 2 keV) is not well established. It is important to better understand the SGR burst spectral properties at lower energies since inadequate description of the burst spectral continuum could lead to incorrect conclusions, such as existence of spectral lines. Here, we present detailed spectral investigations (in 2-200 keV) of 163 bursts from SGR 1806-20, all detected with Rossi X-ray Timing Explorer during the 2004 active episode that included the giant flare on 27 December 2004. We find that the great majority of burst spectra are well represented by the combination of a blackbody plus a OTTB models
Variable Spin-down in the Soft Gamma Repeater SGR 1900+14 and Correlations with Burst Activity
We have analyzed Rossi X-ray Timing Explorer Proportional Counter Array
observations of the pulsed emission from SGR 1900+14 during September 1996,
June - October 1998, and early 1999. Using these measurements and results
reported elsewhere, we construct a period history of this source for 2.5 years.
We find significant deviations from a steady spin-down trend during quiescence
and the burst active interval. Burst and Transient Source Experiment
observations of the burst emission are presented and correlations between the
burst activity and spin-down rate of SGR 1900+14 are discussed. We find an 80
day interval during the summer of 1998 when the average spin-down rate is
larger than the rate elsewhere by a factor ~ 2.3. This enhanced spin-down may
be the result of a discontinuous spin-down event or ``braking glitch'' at the
time of the giant flare on 27 August 1998. Furthermore, we find a large
discrepancy between the pulsar period and average spin-down rate in X-rays as
compared to radio observations for December 1998 and January 1999.Comment: 6 pages, 2 figures, submitted to ApJ Letter
COMPARAĂĂO GRĂFICA ENTRE CURVAS DE ĂNDICE DE SĂTIO PARA Pinus elliottii E Pinus taeda DESENVOLVIDAS NO SUL DO BRASIL
Este trabalho teve como objetivos estudar o crescimento em altura dominante para Pinus elliottii e Pinus taeda, mediante comparaçÔes entre as curvas de Ăndice de sĂtio construĂdas para algumas regiĂ”es do estado do Rio Grande do Sul e outros Estados da Federação. Essas comparaçÔes indicaram que as curvas feitas por Tonini (2000) para as regiĂ”es da Serra do Sudeste e Litoral no estado do Rio Grande do Sul, nĂŁo apresentaram o mesmo desenvolvimento em relação Ă s curvas feitas por Scolforo e Machado (1988), para os estados do ParanĂĄ e Santa Catarina; Brasil (1989a), para a regiĂŁo de Passo Fundo RS, Marcolin (1990), para o Segundo Planalto Paranaense e Selle (1993), para a regiĂŁo de CambarĂĄ do Sul. No entanto, o comportamento em relação Ă s curvas de Ăndice de sĂtio feitas por Brasil (1989b), para a regiĂŁo de SĂŁo Francisco de Paula mostraram-se semelhantes, havendo somente uma diferença de nĂvel entre estas
- âŠ