The practice of web conferencing: where are we now?

The use of web conferencing tools to support learning and teaching and facilitate interaction and collaboration is common in many higher education environments as is the replacement of face-to-face meetings with virtual collaboration tools. This paper reports on Phase 3 of a trial of web conferencing conducted at a regional Australian university and further explores the use of web conferencing to support and enhance learning and teaching. Preliminary findings from Phases 1 and 2 of the trial have been reported on in a previous paper. The action research method which framed the initial trial has again been applied to Phase 3. In Phase 1, collaborative mathematical problem-solving in an undergraduate course was carried out using web conferencing and tablet PCs. In addition, students in postgraduate Education courses were linked across the globe to participate in interactive and collaborative web conference activity. In Phase 2, a university-wide trial across disciplines was conducted. Phase 3 represents an analysis of feedback received from teachers who were involved in Phases 1 and 2 and who have had some time to reflect on the impact web conferencing has had on their teaching practice. From this, and their own experience, the authors make further observations regarding the use of web conferencing to support learning and teaching and raise a number of questions and issues to guide future research

Activating Boxmind: an evaluation of a web‐based video lecture with synchronized activities

The aim of this study was to evaluate the use of synchronous computer‐mediated communication activities in a video e‐lecture. Previous research has reported that learning is facilitated when communication activities are added to a video lecture. Twelve postgraduate students participated in the study and they viewed a video e‐lecture on the perspective‐taking theory of communication. The lecture consisted of a video image of the lecturer, an audio track, slides, the transcript and a number of communication activities. They were given a pre‐test a week before the lecture and a post‐test a week after. They were also asked to rate the helpfulness of various aspects of the lecture. Students’ post‐test scores were statistically significantly higher than their pre‐test scores. They found the audio track, transcript, slides and activities helpful. The most helpful aspects were the communication activities. The implications of these findings are discussed

Diffraction-limited near-IR imaging at Keck reveals asymmetric, time-variable nebula around carbon star CIT 6

We present multi-epoch, diffraction-limited images of the nebula around the carbon star CIT 6 at 2.2 microns and 3.1 microns from aperture masking on the Keck-I telescope. The near-IR nebula is resolved into two main components, an elongated, bright feature showing time-variable asymmetry and a fainter component about 60 milliarcseconds away with a cooler color temperature. These images were precisely registered (~35 milliarcseconds) with respect to recent visible images from the Hubble Space Telescope (Trammell et al. 2000), which showed a bipolar structure in scattered light. The dominant near-IR feature is associated with the northern lobe of this scattering nebula, and the multi-wavelength dataset can be understood in terms of a bipolar dust shell around CIT 6. Variability of the near-IR morphology is qualitatively consistent with previously observed changes in red polarization, caused by varying illumination geometry due to non-uniform dust production. The blue emission morphology and polarization properties can not be explained by the above model alone, but require the presence of a wide binary companion in the vicinity of the southern polar lobe. The physical mechanisms responsible for the breaking of spherical symmetry around extreme carbon stars, such as CIT 6 and IRC+10216, remain uncertain.Comment: 18 pages, 5 figures (one in color), to appear in the Astrophysical Journa

Comparison of approximate and numerical analyses of nonlinear combustion instability

At the present time, there are three general analytical techniques available to study problems of unsteady motions in rocket motors: linear stability analysis; approximate nonlinear analysis, founded on examining the behavior of coupled normal modes; and numerical calculations based on the conservation equations for one-dimensional flows. The last two yield the linear results as a limit. It is the main purpose of this paper to check the accuracy of the approximate analysis against the numerical analysis for some special cases. The results provide some justification for using the approximate analysis to study three dimensional problems

The Quasar Pair Q 1634+267 A, B and the Binary QSO vs. Dark Lens Hypotheses

Deep HST/NICMOS H (F160W) band observations of the z=1.96 quasar pair Q 1634+267A,B reveal no signs of a lens galaxy to a 1 sigma threshold of approximately 22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L_* galaxy at z > 0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light ratio of any putative, early-type, lens galaxy to (M/L)_H > 690h_65 (1200h_65) for Omega_0=0.1 (1.0) and H_0=65h_65 km/s/Mpc. We would expect to detect a galaxy somewhere in the field because of the very strong Mg II absorption lines at z=1.1262 in the Q 1634+267 A spectrum, but the HST H-band, I-band (F785LP) and V-band (F555W) images require that any associated galaxy be very under-luminous less than 0.1 L^*_H (1.0 L^*_I) if it lies within less than 40 h^{-1} (100 h^{-1}) kpc from Q 1634+267 A,B. While the large image separation (3.86 arcsec) and the lack of a lens galaxy strongly favor interpreting Q 1634+267A,B as a binary quasar system, the spectral similarity remains a puzzle. We estimate that at most 0.06% of randomly selected quasar pairs would have spectra as similar to each other as the spectra of Q 1634+267 A and B. Moreover, spectral similarities observed for the 14 quasar pairs are significantly greater than would be expected for an equivalent sample of randomly selected field quasars. Depending on how strictly we define similarity, we estimate that only 0.01--3% of randomly drawn samples of 14 quasar pairs would have as many similar pairs as the observational sample.Comment: 24 pages, including 4 figures, LaTex, ApJ accepted, comments from the editor included, minor editorial change

The Optical-Near-IR Spectrum of the M87 Jet From HST Observations

We present 1998 HST observations of M87 which yield the first single-epoch optical and radio-optical spectral index images of the jet at $0.15''$ resolution. We find $\approx 0.67$, comparable to previous measurements, and $\approx 0.9$ ($F_\nu \propto \nu^{-\alpha}$), slightly flatter than previous workers. Reasons for this discrepancy are discussed. These observations reveal a large variety of spectral slopes. Bright knots exhibit flatter spectra than interknot regions. The flattest spectra ($\alpha_o \sim 0.5-0.6$; comparable to or flatter than $\alpha_{ro}$) are found in two inner jet knots (D-East and HST-1) which contain the fastest superluminal components. In knots A, B and C, $\alpha_o$ and $\alpha_{ro}$ are essentially anti-correlated. Near the flux maxima of knots HST-1 and F, changes in $\alpha_{ro}$ lag changes in $\alpha_o$, but in knots D and E, the opposite relationship is observed. This is further evidence that radio and optical emissions in the M87 jet come from substantially different physical regions. The delays observed in the inner jet are consistent with localized particle acceleration, with $t_{acc} << t_{cool}$ for optically emitting electrons in knots HST-1 and F, and $t_{acc} \sim t_{cool}$ for optically emitting electrons in knots D and E. Synchrotron models yield \nu_B \gsim 10^{16} Hz for knots D, A and B, and somewhat lower values, $\nu_B \sim 10^{15}- 10^{16}$ Hz, in other regions. If X-ray emissions from knots A, B and D are co-spatial with optical and radio emission, we can strongly rule out the ``continuous injection'' model. Because of the short lifetimes of X-ray synchrotron emitting particles, the X-ray emission likely fills volumes much smaller than the optical emission regions.Comment: Text 17 pages, 3 Tables, 11 figures, accepted by Ap

Note: Finger Imaging: A 21st Century Solution to Welfare Fraud at our Fingertips

This Note describes the finger imaging process and summarizes the current New York Social Services law regarding public assistance. It also outlines the current finger imaging bill before the New York State Legislature. Part III examines and considers the two major policy arguments against the implementation of the program. Part IV outlines the legal controversy regarding finger imaging and addresses each express concern as well as constitutional issues. Part V compares New York\u27s finger imaging legislation with similar legislation already in place in California and argues that the New York program will be as effective as California\u27s. In conclusion, this Note urges the New York State Legislature to enact a statewide finger imaging requirement for public assistance and embrace the finger imaging system as an effective and proper method of combatting welfare fraud in the state

Note: Finger Imaging: A 21st Century Solution to Welfare Fraud at our Fingertips

This Note describes the finger imaging process and summarizes the current New York Social Services law regarding public assistance. It also outlines the current finger imaging bill before the New York State Legislature. Part III examines and considers the two major policy arguments against the implementation of the program. Part IV outlines the legal controversy regarding finger imaging and addresses each express concern as well as constitutional issues. Part V compares New York\u27s finger imaging legislation with similar legislation already in place in California and argues that the New York program will be as effective as California\u27s. In conclusion, this Note urges the New York State Legislature to enact a statewide finger imaging requirement for public assistance and embrace the finger imaging system as an effective and proper method of combatting welfare fraud in the state