Collaborative pedagogy and digital scholarship: a case study of 'Media Culture 2020'

This paper presents an educational case study of ‘Media Culture 2020’, an EU Erasmus Intensive Programme that utilised a range social media platforms and computer software to create open, virtual spaces where students from different countries and fields could explore and learn together. The multi-disciplinary project featured five universities from across Europe and was designed to develop new pedagogical frameworks to encourage collaborative approaches to teaching and learning in the arts. The main objective of the project was to break down classroom and campus walls by creating digital learning environments that facilitated new forms of production, transmission and representation of knowledge. Media Culture 2020 was designed to pilot a novel mode of ‘blended learning’, demonstrating a number of ways in which ‘Web 2.0’ networked technologies might be adopted by academics to encourage open and collaborative modes of practice. The project utilised a number of social media platforms (including Facebook, Twitter, Google+, Google Hangout, Google Docs and Blogger) to enhance the learning experiences of a diverse set of students from different cultural and international contexts. In doing so, Media Culture 2020 enabled participants with a diverse range skills and cultural experiences to develop new working practices that respond to the convergence of digital media and art, as well as the internationalisation of media production and business, through the use of open, interactive software

The Transitional Protoplanetary Disk Frequency as a Function of Age: Disk Evolution in the Coronet Cluster, Taurus, and Other 1--8 Myr-old Regions

We present Spitzer 3.6--24 micron photometry and spectroscopy for stars in the 1--3 Myr-old Coronet Cluster, expanding upon the survey of Sicilia-Aguilar et al. (2008). Using sophisticated radiative transfer models, we analyze these new data and those from Sicilia-Aguilar et al. (2008) to identify disks with evidence for substantial dust evolution consistent with disk clearing: transitional disks. We then analyze data in Taurus and others young clusters -- IC 348, NGC 2362, and eta Cha -- to constrain the transitional disk frequency as a function of time. Our analysis confirms previous results finding evidence for two types of transitional disks -- those with inner holes and those that are homologously depleted. The percentage of disks in the transitional phase increases from ~ 15--20% at 1--2 Myr to > 50% at 5--8 Myr; the mean transitional disk lifetime is closer to ~ 1 Myr than 0.1--0.5 Myr, consistent with previous studies by Currie et al. (2009) and Sicilia-Aguilar et al. (2009). In the Coronet Cluster and IC 348, transitional disks are more numerous for very low-mass M3--M6 stars than for more massive K5--M2 stars, while Taurus lacks a strong spectral type-dependent frequency. Assuming standard values for the gas-to-dust ratio and other disk properties, the lower limit for the masses of optically-thick primordial disks is Mdisk ~ 0.001--0.003 M*. We find that single color-color diagrams do not by themselves uniquely identify transitional disks or primordial disks. Full SED modeling is required to accurately assess disk evolution for individual sources and inform statistical estimates of the transitional disk population in large samples using mid-IR colors.Comment: 43 pages in emulateapj format, Accepted for publication in Ap

Investigation of Kepler Objects of Interest Stellar Parameters from Observed Transit Durations

The Kepler mission discovery of candidate transiting exoplanets (KOIs) enables a plethora of ensemble analysis of the architecture and properties of exoplanetary systems. We compare the observed transit durations of KOIs to a synthetic distribution generated from the known eccentricities of radial velocity (RV) discovered exoplanets. We find that the Kepler and RV distributions differ at a statistically significant level. We identify three related systematic trends that are likely due to errors in stellar radii, which in turn affect the inferred exoplanet radii and the distribution thereof, and prevent a valid analysis of the underlying ensemble eccentricity distribution. First, 15% of KOIs have transit durations >20% longer than the transit duration expected for an edge-on circular orbit, including 92 KOIs with transit durations >50% longer, when only a handful of such systems are expected. Second, the median transit duration is too long by up to ~25%. Random errors of <50% in the stellar radius are not adequate to account for these two trends, and they are present for all spectral types in the Kepler sample. We identify that incorrect estimates of stellar metallicity and extinction could account for these anomalies, rather than astrophysical effects such as eccentric exoplanets improbably transiting near apastron. Third, we find that the median transit duration is correlated with stellar radius, when no such trend is expected. All three effects are still present, although less pronounced, when considering only multiple transiting KOI systems which are thought to have a low false positive rate. Improved stellar parameters for KOIs are necessary for the validity of future ensemble tests of exoplanetary systems found by Kepler.Comment: PASP, in pres

DESCRIBING MEMORIES- THE RELATIONSHIP BETWEEN SEMANTICS AND THE SELF-CONCEPT

This study focused on the effects of semantic autobiographical memory (AM) retrieval on one’s self-concept. Participants recalled and wrote about up to four life chapters (specific time periods during their life) or recalled and wrote about up to four general knowledge (GK) stories (i.e. non personal information) in the form of fairy tales. The fluency and accessibility of the self-concept was measured using the “I Am” assessment (Charlesworth, 2015), and was operationalized as three different identity statements: personality traits, physical traits, and identity roles. Participants were initially given one minute to generate as many “I Am” statements as possible (i.e., Fluency portion), and were then given as much time as needed to generate all 20 statements (i.e., Accessibility portion). Participants then used a Likert scale to rate the information they recalled out of five points. In the Fluency portion, the control (fairy tale) group, who recalled GK, generated significantly more personality traits relative to the experimental (life-chapter) group, who recalled semantic AMs. During the Accessibility portion, the life chapter group generated significantly more identity roles relative to the fairy tale group. There were also differences in the total number of personality traits generated for the fairy tale group, relative to the life chapter group, however, this group difference was only marginally significant

A Spitzer Study of Debris Disks in the Young Nearby Cluster NGC 2232: Icy Planets Are Common around ~1.5-3 M☉ Stars

We describe Spitzer IRAC and MIPS observations of the nearby 25 Myr old open cluster NGC 2232. Combining these data with ROSAT All-Sky Survey observations, proper motions, and optical photometry/spectroscopy, we construct a list of highly probable cluster members. We identify one A-type star, HD 45435, that has definite excess emission at 4.5-24 μm indicative of debris from terrestrial planet formation. We also identify 2-4 late-type stars with possible 8 μm excesses and 8 early-type stars with definite 24 μm excesses. Constraints on the dust luminosity and temperature suggest that the detected excesses are produced by debris disks. From our sample of B and A stars, stellar rotation appears to be correlated with 24 μm excess, a result that would be expected if massive primordial disks evolve into massive debris disks. To explore the evolution of the frequency and magnitude of debris around A-type stars, we combine our results with data for other young clusters. The frequency of debris disks around A-type stars appears to increase from ~25% at 5 Myr to ~50%-60% at 20-25 Myr. Older A-type stars have smaller debris disk frequencies: ~20% at 50-100 Myr. For these ages, the typical level of debris emission increases from 5 to 20 Myr and then declines. Because 24 μm dust emission probes icy planet formation around A-type stars, our results suggest that the frequency of icy planet formation is ηi ≳ 0.5-0.6. Thus, most A-type stars (≈1.5-3 M☉) produce icy planets

Effect of impact ionization in scaled pHEMTs

The effect of impact ionization on pseudomorphic high electron mobility transistors is studied using Monte Carlo simulations when these devices are scaled into deep decanano dimensions. The scaling of devices with gate lengths of 120, 90, 70, 50 and 30 nm has been performed in both lateral and vertical directions. The impact ionization is treated as an additional scattering mechanism in the Monte Carlo module. The critical drain voltage, at which device characteristics begin to indicate breakdown, decreases as the gate voltage is lowered. Similarly, the breakdown drain voltage is also found to decrease during the scaling process