17,358 research outputs found
An acoustic charge transport imager for high definition television applications
In this report we present the progress during the second six month period of the project. This includes both experimental and theoretical work on the acoustic charge transport (ACT) portion of the chip, the theoretical program modelling of both the avalanche photodiode (APD) and the charge transfer and overflow transistor and the materials growth and fabrication part of the program
Taking stock of SLSN and LGRB host galaxy comparison using a complete sample of LGRBs
Long gamma-ray bursts (LGRBs) and superluminous supernovae (SLSNe) are both
explosive transients with very massive progenitor stars. Clues about the nature
of the progenitors can be found by investigating environments in which such
transients occur. While studies of LGRB host galaxies have a long history,
dedicated observational campaigns have only recently resulted in a high enough
number of photometrically and spectroscopically observed SLSN hosts to allow
statistically significant analysis of their properties. In this paper we make a
comparison of the host galaxies of hydrogen-poor (H-poor) SLSNe and the
Swift/BAT6 sample of LGRBs. In contrast to previous studies we use a complete
sample of LGRBs and we address a special attention to the comparison
methodology and the selection of SLSN sample whose data have been compiled from
the available literature. At intermediate redshifts (0.3 < z < 0.7) the two
classes of transients select galaxies whose properties (stellar mass,
luminosity, star-formation rate, specific star-formation rate and metallicity)
do not differ on average significantly. Moreover, the host galaxies of both
classes of objects follow the fundamental metallicity relation and the
fundamental plane of metallicity. In contrast to previous studies we show that
at intermediate redshifts the emission line equivalent widths of the two
populations are essentially the same and that the previous claims regarding the
higher fraction of SLSN hosts among the extreme emission line galaxies with
respect to LGRBs are mostly due to a larger fraction of strong-line emitters
among SLSN hosts at z < 0.3, where samples of LGRB hosts are small and poorly
defined.Comment: 7 pages, 4 figures, accepted to Astronomy & Astrophysic
Characterizing the dynamical importance of network nodes and links
The largest eigenvalue of the adjacency matrix of the networks is a key
quantity determining several important dynamical processes on complex networks.
Based on this fact, we present a quantitative, objective characterization of
the dynamical importance of network nodes and links in terms of their effect on
the largest eigenvalue. We show how our characterization of the dynamical
importance of nodes can be affected by degree-degree correlations and network
community structure. We discuss how our characterization can be used to
optimize techniques for controlling certain network dynamical processes and
apply our results to real networks.Comment: 4 pages, 4 figure
Inspiring minds: How big questions can build students’ epistemic insight and improve attitudes towards STEM
This article examines the impact that an ‘epistemically insightful’ approach to informal science learning can have on students’ attitudes, aspirations and perceptions of STEM subjects. It uses interim findings from a research and outreach project, including sustained Saturday activity programmes for ages14–16 and residential summer schools for ages 15–19, designed to create confident scholars who can engage with difficult philosophical questions raised by current technological advances. The Inspiring Minds project at Canterbury Christ Church University, Kent, UK, delivers informal science learning in schools and informal settings based on an epistemic insight-led approach to STEM outreach and education
Childhood development stages and learning on global issues
This helpdesk report provides a summary of available literature and evidence relating to childhood development stages; specifically, when is the best time to influence children’s thinking on global issues. This question is related to a second query covered in a separate helpdesk report that examines the development education landscape in the UK: specifically, what else apart from British Council’s Connecting Classrooms Programme is going on to build partnerships between schools in the UK and schools overseas? How many children/schools are part of something like this?
These helpdesk reports are designed to help inform a business case and guide the Department for International Development’s thinking for a new approach to delivering development education in the UK when the current phases of Connecting Classrooms and the Global Learning Programme ends.
K4D helpdesk reports provide summaries of current research, evidence and lessons learned. This report was commissioned by DFID
1.65 micrometers (H-band) surface photometry of galaxies. III: observations of 558 galaxies with the TIRGO 1.5m telescope
We present near-infrared H-band (1.65 micron) surface photometry of 558
galaxies in the Coma Supercluster and in the Virgo cluster. This data set,
obtained with the Arcetri NICMOS3 camera ARNICA mounted on the Gornergrat
Infrared Telescope, is aimed at complementing, with observations of mostly
early-type objects, our NIR survey of spiral galaxies in these regions,
presented in previous papers of this series. Magnitudes at the optical radius,
total magnitudes, isophotal radii and light concentration indices are derived.
We confirm the existence of a positive correlation between the near-infrared
concentration index and the galaxy H-band luminosity. (Tables 1 and 2 are only
available in electronic form upon request to [email protected])Comment: 12 pages, 6 figures. Accepted for publication in A&A
Primary education for global learning and sustainability
This is one of a series of research reports commissioned by the Cambridge Primary Review Trust (CPRT), a notfor-profit company established in December 2012 with the aim of consolidating and building on the evidence,
findings and principles of the Cambridge Primary Review. Cambridge Primary Review Trust is supported by
Pearson Education, based at the University of York and chaired by Professor Robin Alexander. A briefing which summarises key issues from this report is also available. The report and briefing may be downloaded from the Trust’s website: www.cprtrust.org.uk. The website also provides information and other reports in this series, and about the many publications of the Cambridge Primary Review
An acoustic charge transport imager for high definition television applications
The primary goal of this research is to develop a solid-state high definition television (HDTV) imager chip operating at a frame rate of about 170 frames/sec at 2 Megapixels per frame. This imager offers an order of magnitude improvement in speed over CCD designs and will allow for monolithic imagers operating from the IR to the UV. The technical approach of the project focuses on the development of the three basic components of the imager and their integration. The imager chip can be divided into three distinct components: (1) image capture via an array of avalanche photodiodes (APD's), (2) charge collection, storage and overflow control via a charge transfer transistor device (CTD), and (3) charge readout via an array of acoustic charge transport (ACT) channels. The use of APD's allows for front end gain at low noise and low operating voltages while the ACT readout enables concomitant high speed and high charge transfer efficiency. Currently work is progressing towards the development of manufacturable designs for each of these component devices. In addition to the development of each of the three distinct components, work towards their integration is also progressing. The component designs are considered not only to meet individual specifications but to provide overall system level performance suitable for HDTV operation upon integration. The ultimate manufacturability and reliability of the chip constrains the design as well. The progress made during this period is described in detail in Sections 2-4
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