1,312 research outputs found
Design and construction of the IMACS-IFU, a 2000-element integral field unit
The IMACS-IFU is an Integral Field Unit built for the IMACS spectrograph at
the Magellan-I-Telescope at Las Campanas Observatory. It consists of two
rectangular fields of 5 by 7 arcseconds, separated by roughly one arcminute.
With a total number of 2000 spatial elements it is the second largest
fiber-lenslet based IFU worldwide, working in a wavelength range between 400
and 900 nm. Due to the equally sized fields classical background subtraction,
beam switching and shuffling are possible observation techniques. One
particular design challenge was the single, half a metre long curved slit in
combination with a non telecentric output. Besides the construction some
preliminary results are described.Comment: 10 pages, 7 figures, 1 table. Proceedings for SPIE poster 5492-175 of
SPIE Symposium "Astronomical Telescopes and Instrumentation", June 2004,
Glasgo
Promoting Education for Sustainable Development with an Interactive Digital Learning Companion Students Use to Perform Collaborative Phosphorus Recovery Experiments and Reporting
Multitouch learning books (MLBs) are learning companions that support learning within a series, independent of the learning location. These MLBs can accompany an experiment itself or an entire learning process. In addition to providing interactive tasks, an all-in-one solution can provide pupils with additional information, supporting and differentiating aids, in-depth exercises, and collaborative tasks in one location. This Article presents an interactive learning companion that facilitates student learning through digital interaction while also developing concepts of sustainability in students’ minds. For this purpose, a learning scenario was developed that simulates a virtual learning company in an interactive e-book that corresponds to real experiments carried out in a laboratory. Using this interactive e-book, pupils receive e-mail messages from their “supervisors,” give account to the “board of directors,” and finally evaluate four real processes for phosphorus recovery. The entire series was qualitatively tested with 89 tenth-grade students. Assessment of these students found a significant increase in their use and understanding of digital tools and awareness of education for sustainable development concepts
Design and manufacture of micro-optical arrays using 3D diamond machining techniques
We describe our work towards the manufacture of micro-optical arrays using
freeform diamond machining techniques. Simulations have been done to show the
feasibility of manufacturing micro-lens arrays using the slow-tool servo
method. Using this technique, master shapes can be produced for replication of
micro-lens arrays of either epoxy-on-glass or monolthic glass types. A machine
tool path programme has been developed on the machine software platform
DIFFSYS, allowing the production of spherical, aspherical and toric arrays. In
addition, in theory spatially varying lenslets, sparse arrays and dithered
lenslet arrays (for high contrast applications) are possible to produce. In
practice, due to the diamond tool limitations not all formats are feasible.
Investigations into solving this problem have been carried out and a solution
is presented here.Comment: 8 pages, 11 figures. Copyright 2006 Society of Photo-Optical
Engineers. This paper will be published in SPIE Conf. Series 6273 and is made
available as an electronic preprint with permission of SPIE. One print or
electronic copy may be made for personal use only. Systematic or multiple
reproduction, distribution to multiple locations via electronic or other
means, duplication of any material in this paper for a fee or commercial
purposes, or modification of the content of the paper are prohibite
Baby Boomers’ Attitudes Towards Product Placements
Including branded products within mass media programming is becoming common. Previous research has focused almost entirely on college-age students\u27 attitudes about placements in movies and television. This research focuses on Baby Boomers and is the first to include questions about multiple media in forming attitudes towards product placements. Six hypotheses were tested. Attitude toward product placement is related to media consumption. Males appear more positive than females. Interactions effects of media consumption x gender and media consumption x age appear insignificant. Analytical results, graphs, tables and managerial implications and representative comments from respondents are presented
SST-GATE: A dual mirror telescope for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) will be the world's first open
observatory for very high energy gamma-rays. Around a hundred telescopes of
different sizes will be used to detect the Cherenkov light that results from
gamma-ray induced air showers in the atmosphere. Amongst them, a large number
of Small Size Telescopes (SST), with a diameter of about 4 m, will assure an
unprecedented coverage of the high energy end of the electromagnetic spectrum
(above ~1TeV to beyond 100 TeV) and will open up a new window on the
non-thermal sky. Several concepts for the SST design are currently being
investigated with the aim of combining a large field of view (~9 degrees) with
a good resolution of the shower images, as well as minimizing costs. These
include a Davies-Cotton configuration with a Geiger-mode avalanche photodiode
(GAPD) based camera, as pioneered by FACT, and a novel and as yet untested
design based on the Schwarzschild-Couder configuration, which uses a secondary
mirror to reduce the plate-scale and to allow for a wide field of view with a
light-weight camera, e.g. using GAPDs or multi-anode photomultipliers. One
objective of the GATE (Gamma-ray Telescope Elements) programme is to build one
of the first Schwarzschild-Couder prototypes and to evaluate its performance.
The construction of the SST-GATE prototype on the campus of the Paris
Observatory in Meudon is under way. We report on the current status of the
project and provide details of the opto-mechanical design of the prototype, the
development of its control software, and simulations of its expected
performance.Comment: In Proceedings of the 33rd International Cosmic Ray Conference
(ICRC2013), Rio de Janeiro (Brazil). All CTA contributions at arXiv:1307.223
Stable longitudinal associations of family income with children's hippocampal volume and memory persist after controlling for polygenic scores of educational attainment
Despite common notion that the correlation of socioeconomic status with child cognitive performance may be driven by both environmentally- and genetically-mediated transactional pathways, there is a lack of longitudinal and genetically informed research that examines these postulated associations. The present study addresses whether family income predicts associative memory growth and hippocampal development in middle childhood and tests whether these associations persist when controlling for DNA-based polygenic scores of educational attainment. Participants were 142 6-to-7-year-old children, of which 127 returned when they were 8-to-9 years old. Longitudinal analyses indicated that the association of family income with children's memory performance and hippocampal volume remained stable over this age range and did not predict change. On average, children from economically disadvantaged background showed lower memory performance and had a smaller hippocampal volume. There was no evidence to suggest that differences in memory performance were mediated by differences in hippocampal volume. Further exploratory results suggested that the relationship of income with hippocampal volume and memory in middle childhood is not primarily driven by genetic variance captured by polygenic scores of educational attainment, despite the fact that polygenic scores significantly predicted family income
Root cortex development is fine-tuned by the interplay of MIGs, SCL3 and DELLAs during arbuscular mycorrhizal symbiosis
Root development is a crucial process that determines the ability of plants to acquire nutrients, adapt to the substrate and withstand changing environmental conditions. Root plasticity is controlled by a plethora of transcriptional regulators that allow, in contrast to tissue development in animals, post-embryonic changes that give rise to new tissue and specialized cells.
One of these changes is the accommodation in the cortex of hyperbranched hyphae of symbiotic arbuscular mycorrhizal (AM) fungi, called arbuscules. Arbuscule-containing cells undergo massive reprogramming to coordinate developmental changes with transport processes.
Here we describe a novel negative regulator of arbuscule development, MIG3. MIG3 induces and interacts with SCL3, both of which modulate the activity of the central regulator DELLA, restraining cortical cell growth. As in a tug-of-war, MIG3-SCL3 antagonizes the function of the complex MIG1-DELLA, which promotes the cell expansion required for arbuscule development, adjusting cell size during the dynamic processes of the arbuscule life cycle.
Our results in the legume plant Medicago truncatula advance the knowledge of root development in dicot plants, showing the existence of additional regulatory elements not present in Arabidopsis that fine-tune the activity of conserved central modules
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