675 research outputs found
Designing the future of primary and secondary-level learning environments in knowmad society
In an era consumed with accelerating technological and social change, coupled with rapidly evolving organizational needs and missions, primary and secondary-level schools need to reframe why, how, and for whom they exist and explore new pathways to realize these functions. This article explores a strategic framework for learners to develop skills to navigate a society in constant flux, disentangling information, knowledge, and innovation. We plot a pathway for maximizing creativity and innovation capital for schools in knowledge-based societies, together with the communities they serve
Technical Order Library in Orbit
This paper is a follow-on technical analysis of M The Technical Order Library in Orbit 11,! a paper written by Mr. Rene M. Winz, Titan I Technical Writing Chief, and presented to our Denver Division and corporate management last summer. In his paper, Mr. Winz proposed three alternate methods of providing technical order support to a manned orbital space station. These were: ground station-to-space station, orbiting data station, and on-board technical orders (in microform). His conclusion recommended the ground station-to-space station approach.
Mr. Moravec and I have elected to expand on all three of the philosophies and present possible methods of accomplishing; data storage, transmission, receipt, and display; not only for manned orbital space stations, but also for manned space vehicles
Appearance-based localization for mobile robots using digital zoom and visual compass
This paper describes a localization system for mobile robots moving in dynamic indoor environments, which uses probabilistic integration of visual appearance and odometry information. The approach is based on a novel image matching algorithm for appearance-based place recognition that integrates digital zooming, to extend the area of application, and a visual compass. Ambiguous information used for recognizing places is resolved with multiple hypothesis tracking and a selection procedure inspired by Markov localization. This enables the system to deal with perceptual aliasing or absence of reliable sensor data. It has been implemented on a robot operating in an office scenario and the robustness of the approach demonstrated experimentally
Electrical properties of CdTe near the melting point
A new experimental setup for the investigation of electrical conductivity (σ) in liquid and solid CdTe was built for a better understanding of the properties near the melting point (MP). The temperature dependence of σ was studied, within the interval 1,050-1,130°C, at defined Cd-partial pressures 1.3-1.6 atm, with special attention to the liquid-solid phase transition. We found that the degree of supercooling decreases with increasing Cd overpressure and reaches the lowest value at 1.6 atm without change of the melting temperature during heating
The Arf6 GEF GEP100/BRAG2 Regulates Cell Adhesion by Controlling Endocytosis of β1 Integrins
SummaryThe small GTPase Arf6 has been shown to regulate the post-endocytic trafficking of a subset of membrane proteins, including β1 integrins, and inhibition of Arf6 function impairs both cell adhesion and motility [1]. The activity of Arf GTPases is regulated by a large family of guanine nucleotide exchange factors (GEFs) [2]. Arf-GEP100/BRAG2 is a GEF with reported specificity for Arf6 in vitro [3], but it is otherwise poorly characterized. Here we report that BRAG2 exists in two ubiquitously expressed isoforms, which we call BRAG2a and BRAG2b, both of which can activate Arf6 in vivo. Depletion of endogenous BRAG2 by siRNA leads to dramatic effects in the cell periphery; one such effect is an accumulation of β1 integrin on the cell surface and a corresponding enhancement of cell attachment and spreading on fibronectin-coated substrates. In contrast, depletion of Arf6 leads to intracellular accumulation of β1 integrin and reduced adhesion and spreading. These findings suggest that Arf6 regulates both endocytosis and recycling of β1 integrins and that BRAG2 functions selectively to activate Arf6 during integrin internalization
Self-calibration and improving image fidelity for ALMA and other radio interferometers
This manual is intended to help ALMA and other interferometer users improve
images by recognising limitations and how to overcome them and deciding when
and how to use self-calibration. The images provided by the ALMA Science
Archive are calibrated using standard observing and data processing routines,
including a quality assurance process to make sure that the observations meet
the proposer's science requirements. This may not represent the full potential
of the data, since any interferometry observation can be imaged with a range of
resolutions and surface brightness sensitivity. The separation between phase
calibration source and target usually limits the target dynamic range to a few
hundred (or 50--100 for challenging conditions) but if the noise in the target
field has not reached the thermal limit, improvements may be possible using
self-calibration. This often requires judgements based on the target properties
and is not yet automated for all situations. This manual provides background on
the instrumental and atmospheric causes of visibility phase and amplitude
errors, their effects on imaging and how to improve the signal to noise ratio
and image fidelity by self-calibration. We introduce the conditions for
self-calibration to be useful and how to estimate calibration parameter values
for a range of observing modes (continuum, spectral line etc.). We also
summarise more general error recognition and other techniques to tackle imaging
problems. The examples are drawn from ALMA interferometric data processed using
CASA, but the principles are generally applicable to most similar cm to sub-mm
imaging.Comment: 76 pages, 55 figures, ALMA Memo serie
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