263 research outputs found
Future Proof and Real-World Ready: The Role of Live Project-Based Learning in Students’ Skill Development
The rapid pace of technological change taking place today makes it even more important for marketing educators to incorporate relevant technical and higher level meta-skills in their digital marketing courses. We review the pedagogical literature on skill development and project-based learning and detail two live course projects designed to help students develop technical skills related to digital marketing in addition to important meta-skills involving creativity, critical thinking, collaboration, and communication. We evaluate the impact of the projects through a direct and indirect assessment process. Findings suggest that live project–based learning can support the development of the technical and meta-skills necessary for students to adapt to uncertainty and ambiguity and become future proof and real-world ready as they enter the workforce. We discuss the benefits and challenges associated with moving digital marketing education from conceptual to real-life projects and highlight pedagogical recommendations for educators who want to integrate live project-based learning into their courses
Cyclic Variability of the Circumstellar Disc of the Be Star Tau. II. Testing the 2D Global Disc Oscillation Model
Aims. In this paper we model, in a self-consistent way, polarimetric,
photometric, spectrophotometric and interferometric observations of the
classical Be star Tauri. Our primary goal is to conduct a critical
quantitative test of the global oscillation scenario. Methods. We have carried
out detailed three-dimensional, NLTE radiative transfer calculations using the
radiative transfer code HDUST. For the input for the code we have used the most
up-to-date research on Be stars to include a physically realistic description
for the central star and the circumstellar disc. We adopt a rotationally
deformed, gravity darkened central star, surrounded by a disc whose unperturbed
state is given by a steady-state viscous decretion disc model. We further
assume that disc is in vertical hydrostatic equilibrium. Results. By adopting a
viscous decretion disc model for Tauri and a rigorous solution of the
radiative transfer, we have obtained a very good fit of the time-average
properties of the disc. This provides strong theoretical evidence that the
viscous decretion disc model is the mechanism responsible for disc formation.
With the global oscillation model we have successfully fitted spatially
resolved VLTI/AMBER observations and the temporal V/R variations of the
H and Br lines. This result convincingly demonstrates that the
oscillation pattern in the disc is a one-armed spiral. Possible model
shortcomings, as well as suggestions for future improvements, are also
discussed.Comment: 14 pages, 9 figures, accepted to A&
Relationship Between Isometric Inter-Limb Asymmetry and Strength of the Lower Extremity in Military Personnel
School librarians as literacy educators within a complex role
Librarians in schools are expected to play an important role as literacy educators, and have a positive impact on young people’s literacy learning. However in the context of their diverse workload, relatively little is known about how this aspect of their role sits within its competing demands, and the exact scope of the literacy educator requirements. Using a hybrid approach to content analysis, this article analyses 40 recent job description documents to identify the nature and prevalence of different aspects of the role, and to explore the literacy educator aspect of this profession. Findings suggest that while the literacy educator aspect is one of the most common role requirements, it sits within a complex workload, and the literacy educator aspect is itself multi-faceted and demanding
Collective pulsational velocity broadening due to gravity modes as a physical explanation for macroturbulence in hot massive stars
We aimed at finding a physical explanation for the occurrence of
macroturbulence in the atmospheres of hot massive stars, a phenomenon found in
observations since more than a decade but yet unexplained. We computed time
series of line profiles for evolved massive stars broadened by rotation and by
hundreds of low-amplitude nonradial gravity-mode pulsations which are predicted
to be excited for evolved massive stars. In general, line profiles based on
macrotubulent broadening can mimic those subject to pulsational broadening. In
several cases, though, good fits require macroturbulent velocities that pass
the speed of sound for realistic pulsation amplitudes. Moreover, we find that
the rotation velocity can be seriously underestimated by using a simple
parameter description for macroturbulence rather than an appropriate
pulsational model description to fit the line profiles. We conclude that
macroturbulence is a likely signature of the collective effect of pulsations.
We provide line diagnostics and their typical values to decide whether or not
pulsational broadening is present in observed line profiles, as well as a
procedure to avoid an inaccurate estimation of the rotation velocity.Comment: 12 pages, 9 figures, accepted for publication by Astronomy and
Astrophysic
On the periodicities present in the optical light curves of SMC Be/X-ray binaries
We present a comprehensive study of the periodic variations observed in OGLE
I-band light curves of SMC Be/X-ray binaries, discovering new optical
periodicities in 9 systems. We find that these periodicities derive from a
number of mechanisms, notably disturbance of the decretion disk on the orbital
period of the system, and aliased non-radial pulsations. We develop metrics
that allow these mechanisms to be distinguished on the basis of the shape of
the folded optical light curve, and use these metrics to categorise the
periodicities present in \sim 50 SMC binary systems. We conclude that extreme
care must be taken in the interpretation of the OGLE light curves since only
around 30% of the periodicities present can be unambiguously attributed to
orbital periods.Comment: 16 pages, 17 figures, accepted for publication in MNRA
Detection of a Hot Subdwarf Companion to the Be Star FY Canis Majoris
The rapid rotation of Be stars may be caused in some cases by past mass and
angular momentum accretion in an interacting binary in which the mass donor is
currently viewed as a small, hot subdwarf stripped of its outer envelope. Here
we report on the spectroscopic detection of such a subdwarf in the Be binary
system FY Canis Majoris from the analysis of data acquired by the IUE
spacecraft and KPNO Coude Feed Telescope over the course of 16 and 21 years,
respectively. We present a double-lined spectroscopic orbit for the binary
based upon radial velocities from the IUE spectra and use the orbital solutions
with a Doppler tomography algorithm to reconstruct the components' UV spectra.
The subdwarf is hot (T_eff = 45+/-5 kK) and has a mass of about 1.3 M_sun and a
radius of about 0.6 R_sun. It contributes about 4% as much flux as the Be star
does in the FUV. We also present observations of the H-alpha and He I 6678
emission features that are formed in the circumstellar disk of the Be star.
Orbital flux and velocity variations in the He I 6678 profile indicate that
much of the emission forms along the disk rim facing the hot subdwarf where the
disk is probably heated by the incident radiation from the subdwarf. A study of
the FUV infall shell lines discovered in the 1980s confirms their episodic
presence but reveals that they tend to be found around both quadrature phases,
unlike the pattern in Algol binaries. Phase-dependent variations in the UV N V
doublet suggest the presence of a N-enhanced wind from the subdwarf and a
possible shock-interaction region between the stars where the subdwarf's wind
collides with the disk of the Be star.Comment: 46 pages, 15 figures, ApJ in pres
Imaging the heart of astrophysical objects with optical long-baseline interferometry
The number of publications of aperture-synthesis images based on optical
long-baseline interferometry measurements has recently increased due to easier
access to visible and infrared interferometers. The interferometry technique
has now reached a technical maturity level that opens new avenues for numerous
astrophysical topics requiring milli-arcsecond model-independent imaging. In
writing this paper our motivation was twofold: 1) review and publicize
emblematic excerpts of the impressive corpus accumulated in the field of
optical interferometry image reconstruction; 2) discuss future prospects for
this technique by selecting four representative astrophysical science cases in
order to review the potential benefits of using optical long baseline
interferometers. For this second goal we have simulated interferometric data
from those selected astrophysical environments and used state-of-the-art codes
to provide the reconstructed images that are reachable with current or
soon-to-be facilities. The image reconstruction process was "blind" in the
sense that reconstructors had no knowledge of the input brightness
distributions. We discuss the impact of optical interferometry in those four
astrophysical fields. We show that image reconstruction software successfully
provides accurate morphological information on a variety of astrophysical
topics and review the current strengths and weaknesses of such reconstructions.
We investigate how to improve image reconstruction and the quality of the image
possibly by upgrading the current facilities. We finally argue that optical
interferometers and their corresponding instrumentation, existing or to come,
with 6 to 10 telescopes, should be well suited to provide images of complex
sceneries.Comment: Acccepted to Astronomy and Astrophysics Revie
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