4,050 research outputs found
The effect of a random sampling interval on a sampled-data model of the human operator
Effect of random sampling interval on sampled data model of human operator in compensatory trackin
An integrated development facility for the calibration of low-energy charged particle flight instrumentation
A system was developed for the calibration and development of thermal ion instrumentation. The system provides an extended beam with usable current rates, approx. 1 pA/sq cm, at beam energies as low as 1 eV, with much higher values available with increasing energy. A tandem electrostatic and variable geometry magnetic mirror configuration within the ion source optimizes the use of the ionizing electrons. The system is integrated under microcomputer control to allow automatic control and monitoring of the beam energy and composition and the mass and angle-dependent response of the instrument under test. The system is pumped by a combination of carbon vane and cryogenic sorption roughing pumps and ion and liquid helium operating pumps
Password Generators:Old Ideas and New
This paper considers password generators, i.e. systems designed to generate
site-specific passwords on demand. Such systems are an alternative to password
managers. Over the last 15 years a range of password generator systems have
been described. This paper proposes the first general model for such systems,
and critically examines options for instantiating this model; options
considered include all those previously proposed as part of existing schemes as
well as certain novel possibilities. The model enables a more objective and
high-level assessment of the design of such systems; it has also been used to
sketch a possible new scheme, AutoPass, intended to incorporate the best
features of the prior art whilst also addressing many of the most serious
shortcomings of existing systems through the inclusion of novel features.Comment: This is the full version of a paper with the same title due to be
published in the proceedings of WISTP 2016 in September 201
Sedentary behaviour and diet across the lifespan: an updated systematic review.
Sedentary behaviour and its association with dietary intake in young people and adults are important topics and were systematically reviewed in 2011. There is a need to update this evidence given the changing nature of sedentary behaviour and continued interest in this field. This review aims to assist researchers in better interpreting the diversity of findings concerning sedentary behaviour and weight status
Business Success and Businesses' Beauty Capital
We examine whether a difference in pay for beauty is supported by different productivity of people according to looks. Using a sample of advertising firms, we find that those firms with better-looking executives have higher revenues and faster growth than do otherwise identical firms whose executives are not so good-looking. The impact on revenue far exceeds the likely effect of beauty on the executives' wages. This suggests that their beauty creates firm-specific investments, in the form of improved relationships within work groups, the returns to which are shared by the firm and the executive.
Physical activity and mental health in children and adolescents: A review of reviews
Objective: To synthesise reviews investigating physical activity and depression, anxiety, self-esteem and cognitive functioning in children and adolescents and to assess the association between sedentary behaviour and mental health by performing a brief review. Methods: Searches were performed in 2010. Inclusion criteria specifi ed review articles reporting chronic physical activity and at least one mental health outcome that included depression, anxiety/stress, self-esteem and cognitive functioning in children or adolescents. Results: Four review articles reported evidence concerning depression, four for anxiety, three for self-esteem and seven for cognitive functioning. Nine primary studies assessed associations between sedentary behaviour and mental health. Physical activity has potentially benefi cial effects for reduced depression, but the evidence base is limited. Intervention designs are low in quality, and many reviews include cross-sectional studies. Physical activity interventions have been shown to have a small benefi cial effect for reduced anxiety, but the evidence base is limited. Physical activity can lead to improvements in self-esteem, at least in the short term. However, there is a paucity of good quality research. Reviews on physical activity and cognitive functioning have provided evidence that routine physical activity can be associated with improved cognitive performance and academic achievement, but these associations are usually small and inconsistent. Primary studies showed consistent negative associations between mental health and sedentary behaviour. Conclusion:s: Association between physical activity and mental health in young people is evident, but research designs are often weak and effects are small to moderate. Evidence shows small but consistent associations between sedentary screen time and poorer mental health
K2 reveals pulsed accretion driven by the 2 Myr old hot Jupiter CI Tau b
CI Tau is a young (~2 Myr) classical T Tauri star located in the Taurus star
forming region. Radial velocity observations indicate it hosts a Jupiter-sized
planet with an orbital period of approximately 9 days. In this work, we analyze
time series of CI Tau's photometric variability as seen by K2. The lightcurve
reveals the stellar rotation period to be ~6.6 d. Although there is no evidence
that CI Tau b transits the host star, a ~9 d signature is also present in the
lightcurve. We believe this is most likely caused by planet-disk interactions
which perturb the accretion flow onto the star, resulting in a periodic
modulation of the brightness with the ~9 d period of the planet's orbit.Comment: Accepted for publication in ApJ Letter
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