646 research outputs found
Challenges in Collaborative HRI for Remote Robot Teams
Collaboration between human supervisors and remote teams of robots is highly
challenging, particularly in high-stakes, distant, hazardous locations, such as
off-shore energy platforms. In order for these teams of robots to truly be
beneficial, they need to be trusted to operate autonomously, performing tasks
such as inspection and emergency response, thus reducing the number of
personnel placed in harm's way. As remote robots are generally trusted less
than robots in close-proximity, we present a solution to instil trust in the
operator through a `mediator robot' that can exhibit social skills, alongside
sophisticated visualisation techniques. In this position paper, we present
general challenges and then take a closer look at one challenge in particular,
discussing an initial study, which investigates the relationship between the
level of control the supervisor hands over to the mediator robot and how this
affects their trust. We show that the supervisor is more likely to have higher
trust overall if their initial experience involves handing over control of the
emergency situation to the robotic assistant. We discuss this result, here, as
well as other challenges and interaction techniques for human-robot
collaboration.Comment: 9 pages. Peer reviewed position paper accepted in the CHI 2019
Workshop: The Challenges of Working on Social Robots that Collaborate with
People (SIRCHI2019), ACM CHI Conference on Human Factors in Computing
Systems, May 2019, Glasgow, U
Polycyclic aromatic hydrocarbon processing in a hot gas
Context: PAHs are thought to be a ubiquitous and important dust component of
the interstellar medium. However, the effects of their immersion in a hot
(post-shock) gas have never before been fully investigated. Aims: We study the
effects of energetic ion and electron collisions on PAHs in the hot post-shock
gas behind interstellar shock waves. Methods: We calculate the ion-PAH and
electron-PAH nuclear and electronic interactions, above the carbon atom loss
threshold, in H II regions and in the hot post-shock gas, for temperatures
ranging from 10^3 to 10^8 K. Results: PAH destruction is dominated by He
collisions at low temperatures (T < 3x10^4 K), and by electron collisions at
higher temperatures. Smaller PAHs are destroyed faster for T < 10^6 K, but the
destruction rates are roughly the same for all PAHs at higher temperatures. The
PAH lifetime in a tenuous hot gas (n_H ~ 0.01 cm^-3, T ~ 10^7 K), typical of
the coronal gas in galactic outflows, is found to be about thousand years,
orders of magnitude shorter than the typical lifetime of such objects.
Conclusions: In a hot gas, PAHs are principally destroyed by electron
collisions and not by the absorption of X-ray photons from the hot gas. The
resulting erosion of PAHs occurs via C_2 loss from the periphery of the
molecule, thus preserving the aromatic structure. The observation of PAH
emission from a million degree, or more, gas is only possible if the emitting
PAHs are ablated from dense, entrained clumps that have not yet been exposed to
the full effect of the hot gas.Comment: 16 pages, 11 figures, 3 tables, typos corrected and PAH acronym in
the title substituted with full name to match version published in Astronomy
and Astrophysic
Visualising COVID-19 Research
The world has seen in 2020 an unprecedented global outbreak of SARS-CoV-2, a
new strain of coronavirus, causing the COVID-19 pandemic, and radically
changing our lives and work conditions. Many scientists are working tirelessly
to find a treatment and a possible vaccine. Furthermore, governments,
scientific institutions and companies are acting quickly to make resources
available, including funds and the opening of large-volume data repositories,
to accelerate innovation and discovery aimed at solving this pandemic. In this
paper, we develop a novel automated theme-based visualisation method, combining
advanced data modelling of large corpora, information mapping and trend
analysis, to provide a top-down and bottom-up browsing and search interface for
quick discovery of topics and research resources. We apply this method on two
recently released publications datasets (Dimensions' COVID-19 dataset and the
Allen Institute for AI's CORD-19). The results reveal intriguing information
including increased efforts in topics such as social distancing; cross-domain
initiatives (e.g. mental health and education); evolving research in medical
topics; and the unfolding trajectory of the virus in different territories
through publications. The results also demonstrate the need to quickly and
automatically enable search and browsing of large corpora. We believe our
methodology will improve future large volume visualisation and discovery
systems but also hope our visualisation interfaces will currently aid
scientists, researchers, and the general public to tackle the numerous issues
in the fight against the COVID-19 pandemic.Comment: 11 pages. 10 figures. Preprint paper made available here prior to
submission. Update: special characters correcte
The effect of acute sleep extension vs active recovery on post exercise recovery kinetics in rugby union players
Background Elite rugby players experience poor sleep quality and quantity. This lack of sleep could compromise post-exercise recovery. Therefore, it appears central to encourage sleep in order to improve recovery kinetics. However, the effectiveness of an acute ergogenic strategy such as sleep extension on recovery has yet to be investigated among athletes. Aim To compare the effects of a single night of sleep extension to an active recovery session (CON) on post-exercise recovery kinetics. Methods In a randomised cross-over design, 10 male rugby union players participated in two evening training sessions (19:30) involving collision activity, 7-days apart. After each session, participants either extended their sleep to 10 hours or attended an early morning recovery session (07:30). Prior to (PRE), immediately after (POST 0 hour [h]), 14h (POST 14) and 36h (POST 36) post training, neuromuscular, perceptual and cognitive measures of fatigue were assessed. Objective sleep parameters were monitored two days before the training session and over the two-day recovery period. Results The training session induced substantial decreases in countermovement jump mean power and wellness across all time points, while heart rate recovery decreased at POST 0 in both conditions. Sleep extension resulted in greater total sleep time (effect size [90% confidence interval]: 5.35 [4.56 to 6.14]) but greater sleep fragmentation than CON (2.85 [2.00 to 3.70]). Between group differences highlight a faster recovery of cognitive performance following sleep extension (-1.53 [-2.33 to -0.74]) at POST 14, while autonomic function (-1.00 [-1.85 to -0.16]) and upper-body neuromuscular function (-0.78 [-1.65 to 0.08]) were better in CON. However, no difference in recovery status between groups was observed at POST 36. Conclusion The main finding of this study suggests that sleep extension could affect cognitive function positively but did not improve neuromuscular function the day after a late exercise bout.</p
Flexibility within the Heads of Muscle Myosin-2 Molecules
We show that negative-stain electron microscopy and image processing of nucleotide-free (apo) striated muscle myosin-2 subfragment-1 (S1), possessing one light chain or both light chains, is capable of resolving significant amounts of structural detail. The overall appearance of the motor and the lever is similar in rabbit, scallop and chicken S1. Projection matching of class averages of the different S1 types to projection views of two different crystal structures of apo S1 shows that all types most commonly closely resemble the appearance of the scallop S1 structure rather than the methylated chicken S1 structure. Methylation of chicken S1 has no effect on the structure of the molecule at this resolution: it too resembles the scallop S1 crystal structure. The lever is found to vary in its angle of attachment to the motor domain, with a hinge point located in the so-called pliant region between the converter and the essential light chain. The chicken S1 crystal structure lies near one end of the range of flexion observed. The Gaussian spread of angles of flexion suggests that flexibility is driven thermally, from which a torsional spring constant of ~ 23 pN·nm/rad2 is estimated on average for all S1 types, similar to myosin-5. This translates to apparent cantilever-type stiffness at the tip of the lever of 0.37 pN/nm. Because this stiffness is lower than recent estimates from myosin-2 heads attached to actin, we suggest that binding to actin leads to an allosteric stiffening of the motor–lever junction
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