3,495 research outputs found
Haptic dancing: human performance at haptic decoding with a vocabulary
The inspiration for this study is the observation that swing dancing involves coordination of actions between two humans that can be accomplished by pure haptic signaling. This study implements a leader-follower dance to be executed between a human and a PHANToM haptic device. The data demonstrates that the participants' understanding of the motion as a random sequence of known moves informs their following, making this vocabulary-based interaction fundamentally different from closed loop pursuit tracking. This robot leader does not respond to the follower's movement other than to display error from a nominal path. This work is the first step in an investigation of the successful haptic coordination between dancers, which will inform a subsequent design of a truly interactive robot leader
Human-human haptic collaboration in cyclical Fitts' tasks
Understanding how humans assist each other in haptic interaction teams could lead to improved robotic aids to solo human dextrous manipulation. Inspired by experiments reported in Reed et al. (2004), which suggested two-person haptically interacting teams could achieve a lower movement time (MT) than individuals for discrete aiming movements of specified accuracy, we report that two-person teams (dyads) can also achieve lower MT for cyclical, continuous aiming movements. We propose a model, called endpoint compromise, for how the intended endpoints of both subjects' motion combine during haptic interaction; it predicts a ratio of /spl radic/2 between slopes of MT fits for individuals and dyads. This slope ratio prediction is supported by our data
A qualitative exploration of consumersâ perceived impacts, behavioural reactions, and future reflections of the EU Tobacco Products Directive (2017) as applied to electronic cigarettes
Background: Electronic cigarette regulations included in the Tobacco Products Directive (TPD), Article 20, implemented in Europe by May 2017, aimed to improve safety for e-cigarette consumers, and prevent uptake among non-smokers, particularly young people. Before implementation, there were significant concerns from consumers, industry, and some in the scientific community about the potential negative impact of the TPD on people using e-cigarettes to stay stopped from smoking. To date, there is limited evidence on how the TPD has affected consumers. This study aimed to add insight into how consumers perceived and experienced the regulations. Methods: Qualitative data, collected between March 2018 and March 2019, relating to participant views of the TPD were extracted from 160 interviews/extended surveys of e-cigarette consumers as part of a wider study into e-cigarette use trajectories (ECtra study). Data were thematically analysed. Results: Awareness of the TPD amongst consumers was not universal. Participantsâ smoking behaviour did not appear to be influenced by the legislation. Participants were reassured by manufacturing regulations and requirements for ingredients labels. Participants responded negatively to changes perceived to cause inconvenience and extra plastic waste. The product restrictions prompted some participants to purchase non-compliant products illegally, potentially putting their safety at risk. Conclusions: E-cigarette regulation should focus on ensuring product safety. Raising awareness of the TPD amongst consumers and smokers could be beneficial
Enhanced Momentum Feedback from Clustered Supernovae
Young stars typically form in star clusters, so the supernovae (SNe) they
produce are clustered in space and time. This clustering of SNe may alter the
momentum per SN deposited in the interstellar medium (ISM) by affecting the
local ISM density, which in turn affects the cooling rate. We study the effect
of multiple SNe using idealized 1D hydrodynamic simulations which explore a
large parameter space of the number of SNe, and the background gas density and
metallicity. The results are provided as a table and an analytic fitting
formula. We find that for clusters with up to ~100 SNe the asymptotic momentum
scales super-linearly with the number of SNe, resulting in a momentum per SN
that can be an order of magnitude larger than for a single SN, with a maximum
efficiency for clusters with 10-100 SNe. We argue that additional physical
processes not included in our simulations -- self-gravity, breakout from a
galactic disk, and galactic shear -- can slightly reduce the momentum
enhancement from clustering, but the average momentum per SN still remains a
factor of 4 larger than the isolated SN value when averaged over a realistic
cluster mass function for a star-forming galaxy. We conclude with a discussion
of the possible role of mixing between hot and cold gas, induced by
multi-dimensional instabilities or preexisting density variations, as a
limiting factor in the buildup of momentum by clustered SNe, and suggest future
numerical experiments to explore these effects.Comment: 19 pages, 26 figures, revised to reflect accepted version. Discussion
regarding resolution effects has changed; additional analysis into galactic
and gravitational effects has been adde
Super- and Hyperdeformed Isomeric States and Long-Lived Superheavy Elements
The recent discoveries of the long-lived high spin super- and hyperdeformed
isomeric states and their unusual radioactive decay properties are described.
Based on their existence a consistent interpretation is given to the production
of the long-lived superheavy element with Z = 112, via secondary reactions in
CERN W targets, and to the low energy and very enhanced alpha-particle groups
seen in various actinide fractions separated from the same W target. In
addition, consistent interpretations are suggested for previously unexplained
phenomena seen in nature. These are the Po halos, the low-energy enhanced 4.5
MeV alpha-particle group proposed to be due to an isotope of a superheavy
element with Z = 108, and the giant halos.Comment: 4 pages. Contribution to the 2nd Int. Conf. on the Chemistry and
Physics of the Transactinide Elements (TAN 03) Napa California, November 200
Techniques development for whale migration tracking
Effort leading to the completion of development and fabrication of expansible whale harnesses and whale-carried instrument pods is described, along with details of the gear. Early preparative effort for a January-February 1974 field expedition is reported
Efficacy of phenothiazine in the treatment of sheep for control of internal parasites
"February, 1946."Treating ewes once in December and once the following March with a full dose of liquid phenothiazine and every 28 days thereafter with 1 1/2 per cent copper sulphate until the following December did not control nodular worm infestation even though at the beginning of the experiment the sheep were placed upon clean pasture.Treating sheep with liquid phenothiazine every four weeks from December to March (giving a total of four treatments) and then giving them 1 1/2 per cent copper sulphate every 28 days did not
control nodular worm infestations. The 1 1/2 per cent copper sulphate solution was found very satisfactory in keeping the lambs free from Haemonchus contortus. Treating sheep with liquid phenothiazine every four weeks from December to early April and then allowing them access to pheno-thiazine-salt mixture (1 part phenothiazine to 10 parts salt) was very satisfactory in controlling nodular worm infestation. This method of handling sheep held the Haemonchus contortus infestation down to an average of about 19 per lamb. This same method of handling did not satisfactorily control ostertagia, nematodirus, cooperia or tapeworms. Whipworm counts were not materially different in any of the three experiments. Average weight of the lambs was very much higher in Experiment III when the sheep had access to phenothiazine and salt mixture than it was in Experiments I and II. Phenothiazine has not been found toxic to sheep either in a 1 to10 phenothiazine-salt mixture or when the medicine has been given as a drench every 28 days throughout the entire year. The use of phenothiazine has not interfered with breeding efficiency. Worm egg counts by the flotation method have not contributed any aid in this study, but would be useful in sheep infested with only one species of parasite or with species that can be definitely identified by microscopic examination alone
A systematic review of the health and well-being impacts of school gardening: synthesis of quantitative and qualitative evidence
Background: School gardening programmes are increasingly popular, with suggested benefits including healthier eating and increased physical activity. Our objectives were to understand the health and well-being impacts of school gardens and the factors that help or hinder their success.
Methods: We conducted a systematic review of quantitative and qualitative evidence (PROSPERO CRD42014007181). We searched multiple databases and used a range of supplementary approaches. Studies about school gardens were included if they reported on physical or mental health or well-being. Quantitative studies had to include a comparison group. Studies were quality appraised using appropriate tools. Findings were narratively synthesised and the qualitative evidence used to produce a conceptual framework to illustrate how benefits might be accrued.
Results: Evidence from 40 articles (21 quantitative studies; 16 qualitative studies; 3 mixed methods studies) was included. Generally the quantitative research was poor. Evidence for changes in fruit and vegetable intake was limited and based on self-report. The qualitative research was better quality and ascribed a range of health and well-being impacts to school gardens, with some idealistic expectations for their impact in the long term. Groups of pupils who do not excel in classroom activities were thought to particularly benefit. Lack of funding and over reliance on volunteers were thought to threaten success, while involvement with local communities and integration of gardening activities into the school curriculum were thought to support success.
Conclusion: More robust quantitative research is needed to convincingly support the qualitative evidence suggesting wide ranging benefits from school gardens
The momentum budget of clustered supernova feedback in a 3D, magnetised medium
While the evolution of superbubbles driven by clustered supernovae has been
studied by numerous authors, the resulting radial momentum yield is uncertain
by as much as an order of magnitude depending on the computational methods and
assumed properties of the surrounding interstellar medium (ISM). In this work,
we study the origin of these discrepancies, and seek to determine the correct
momentum budget for a homogeneous ISM. We carry out 3D hydrodynamic (HD) and
magnetohydrodynamic (MHD) simulations of clustered supernova explosions, using
a Lagrangian method and checking for convergence with respect to resolution. We
find that the terminal momentum of a shell driven by clustered supernovae is
dictated primarily by the mixing rate across the contact discontinuity between
the hot and cold phases, and that this energy mixing rate is dominated by
numerical diffusion even at the highest resolution we can complete, 0.03
. Magnetic fields also reduce the mixing rate, so that MHD simulations
produce higher momentum yields than HD ones at equal resolution. As a result,
we obtain only a lower limit on the momentum yield from clustered supernovae.
Combining this with our previous 1D results, which provide an upper limit
because they allow almost no mixing across the contact discontinuity, we
conclude that the momentum yield per supernova from clustered supernovae in a
homogeneous ISM is bounded between and
km s. A converged value for the simple homogeneous ISM remains elusive.Comment: 13 page, 11 figures, revised to reflect the published version. Added
a deeper analysis estimating physical and numeric mixing rates (Section 4).
Added addition simulations to the resolution stud
Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th
Evidence for the existence of a superheavy nucleus with atomic mass number
A=292 and abundance (1-10)x10^(-12) relative to 232Th has been found in a study
of natural Th using inductively coupled plasma-sector field mass spectrometry.
The measured mass matches the predictions [1,2] for the mass of an isotope with
atomic number Z=122 or a nearby element. Its estimated half-life of t1/2 >=
10^8 y suggests that a long-lived isomeric state exists in this isotope. The
possibility that it might belong to a new class of long-lived high spin super-
and hyperdeformed isomeric states is discussed.[3-6]Comment: 14 pages, 5 figure
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