4,000 research outputs found
What does not happen: quantifying embodied engagement using NIMI and self-adaptors
Previous research into the quantification of embodied intellectual and emotional engagement using non-verbal movement parameters has not yielded consistent results across different studies. Our research introduces NIMI (Non-Instrumental Movement Inhibition) as an alternative parameter. We propose that the absence of certain types of possible movements can be a more holistic proxy for cognitive engagement with media (in seated persons) than searching for the presence of other movements. Rather than analyzing total movement as an indicator of engagement, our research team distinguishes between instrumental movements (i.e. physical movement serving a direct purpose in the given situation) and non-instrumental movements, and investigates them in the context of the narrative rhythm of the stimulus. We demonstrate that NIMI occurs by showing viewers’ movement levels entrained (i.e. synchronised) to the repeating narrative rhythm of a timed computer-presented quiz. Finally, we discuss the role of objective metrics of engagement in future context-aware analysis of human behaviour in audience research, interactive media and responsive system and interface design
A time series feature of variability to detect two types of boredom from motion capture of the head and shoulders
Boredom and disengagement metrics are crucial to the correctly timed implementation of adaptive interventions in interactive systems. psychological research suggests that boredom (which other HCI teams have been able to partially quantify with pressure-sensing chair mats) is actually a composite: lethargy and restlessness. Here we present an innovative approach to the measurement and recognition of these two kinds of boredom, based on motion capture and video analysis of changes in head and shoulder positions. Discrete, three-minute, computer-presented stimuli (games, quizzes, films and music) covering a spectrum from engaging to boring/disengaging were used to elicit changes in cognitive/emotional states in seated, healthy volunteers. Interaction with the stimuli occurred with a handheld trackball instead of a mouse, so movements were assumed to be non-instrumental. Our results include a feature (standard deviation of windowed ranges) that may be more specific to boredom than mean speed of head movement, and that could be implemented in computer vision algorithms for disengagement detection
Microstructural and Isotopic Constraints on WL Rim Formation
Coordinated microanalyses of Wark-Lovering (WL) rims are needed to best understand their origin and to decipher their subsequent evolution both in the nebular and parent body settings. Here we present the mineralogy, petrology, microstructures, O isotopic compositions, and Al-Mg systematics of a WL rim on a Type B CAI, Big Guy, from the reduced CV3 chondrite Vigarano [1]. Our SEM and TEM study reveals seven distinct mineral layers in the WL rim that include: (1) gehlenite with rare grossite, (2) hibonite, (3) spinel with minor hibonite and perovskite, (4) zoned melilite (k(sub ~0-10)), (5) anorthite, (6) zoned diopside grading outwards from Al,Ti-rich to Al,Tipoor, and (7) forsterite intergrown with diopside. We infer a two-stage history in which WL rim formation was initiated by flash melting and extensive evaporation of the original inclusion edge, followed by subsequent condensation under highly dynamic conditions. The outermost edge of the CAI mantle is mineralogically and texturally distinct compared to the underlying mantle that is composed of coarse, zoned melilite (k(sub ~10-60)) grains. The mantle edge contains finegrained gehlenite with hibonite and rare grossite that likely formed by rapid crystallization from a Ca,Al-rich melt produced during a flash vaporization event [2]. These gehlenite and hibonite layers are surrounded by successive layers of spinel, melilite, diopside, and forsterite, indicating their sequential gas-solid reactions onto hibonite. Anorthite occurs as a discontinuous layer that corrodes adjacent melilite and Al-diopside, and appears to have replaced them [3,4], probably even later than the forsterite layer formation. All the WL rim minerals analyzed using the JSC NanoSIMS 50L are 16O-rich (17O 23), indicating their formation in an 16O-rich gas reservoir. Our data are in contrast with many CV CAIs that show heterogeneous 17O values across their WL rims [5]. Our Al-Mg data obtained using the UCLA ims-1290 ion microprobe of the CAI interior and the WL rim define a well-correlated isochron with (26Al/27Al)(sub 0) = 4.94 10(exp 5), indicating their synchronous formation 5 10(exp 4) years after the canonical CAI value. In contrast, no 26Mg excesses are observed in the WL rim anorthite, which suggests its later formation or later isotopic resetting in an 16O-rich gas reservoir, after 26Al had decayed
Association between match activity variables, measures of fatigue and neuromuscular performance capacity following elite competitive soccer matches
The aim of the study was to assess the relationships between match activity variables, subsequent fatigue and neuromuscular performance capacity in elite soccer players. Subjects (n = 10) were professional soccer players participating in the English Championships. Match activity variables and markers of fatigue status were measured before and following two matches. Creatine kinase (CK) and muscle soreness were measured at baseline, immediately following, as well as 40 and 64 h post-match. Countermovement jump performance and perceived ratings of wellness were measured at baseline, then 40 and 64 h post-match. Relationships were shown between CK and the total number of accelerations and decelerations immediately (r = 0.63; large), 40 h (r = 0.45; moderate) and 64 h post-match (r = 0.35; moderate) (p < 0.05). Relationships between CK and total sprint distance (r = 0.39; moderate) and the number of sprints (r = 0.35; moderate) 40 h post-match (p < 0.05) were observed. Furthermore, relationships were shown between the perceived rating of wellness and number of accelerations 40 (r = 0.52; large) and 64 h (r = 0.40; moderate) post-match, sprint distance 40 h post-match (r = 0.40; moderate) and the total number of sprints 40 h post-match (r = 0.51; large) (p < 0.05). The quantification of match activity variables, particularly the total number of accelerations and decelerations and the number of sprints, provides insights into the fatigue status in elite soccer players 40 and 64 h post-match
Systemdynamische Betrachtungen zur Sturzdynamik und -prophylaxe: Entwicklung eines deterministischen Modells
Zusammenfassung: Hintergrund: Stürze älterer Personen ist derzeit eine große Public-Health-Herausforderung. Da Instrumente zur Erkennung sturzgefährdeter Personen wenig genaue Vorhersagen machen, wurde ein deterministisches systemdynamisches Modell der Sturzdynamik entwickelt. Methoden: Unter Verwendung bekannter Sturzrisikofaktoren, quantitativer Forschungsergebnisse und Abschätzungen, Ursachen- und Wirkbeziehungen wurde ein deterministisches Modell simuliert. Ergebnisse: Grundvoraussetzungen für Stürze sind Bewegung oder Bewegungsabsichten ("Mobilität im Alltag"), ein Sturzrisiko und ein Ungleichgewicht zwischen Gehanforderungen und Gehfähigkeit. Kraft, Koordination und Gleichgewicht wurden als Speichergrößen definiert und Ursache-Wirkungs-Zusammenhänge ins Modell integriert. Zahlreiche andere bekannte Sturzrisikofaktoren wurden ins Modell aufgenommen und quantifiziert. Die Simulation einer Fixierung zeigte, dass die Sturzwahrscheinlichkeit unmittelbar nach der Fixierung erhöht ist. Das Modell zeigt in der Simulation systemdynamische Aspekte wie Verzögerung, Rückkoppelung und Nicht-Linearität. Schlussfolgerung: Mit Hilfe der Systemdynamik konnte ein deterministisches systemdynamisches Modell der Sturzdynamik und -prophylaxe für eine Pflegeheimpopulation unter Einbeziehung bekannter Sturzrisikofaktoren entwickelt werden, das von Praktikern als plausibel beurteilt wird und das "richtungssicher" reagier
Local Variations in Lunar Regolith Thickness: Testing a New Model of Regolith Formation near the Apollo 15 Site
No abstract availabl
Microstructural Investigation of a Wark-Lovering Rim on a Vigarano CAI
Wark-Lovering (WL) rims are thin multi-layered mineral sequences that surround many CAIs. These rim layers consist of the primary minerals found in the CAI interiors, but vary in their mineralogy. Several models for their origin have been proposed including condensation, reaction with a nebular gas, evaporation, or combinations of these. However, there still is little consensus on how and when the rims formed. Here, we describe the microstructure and mineralogy of a WL rim on a type B CAI from the Vigarano CV(sub red) chondrite using FIB/TEM to better understand the astrophysical significance of WL rim formation
Overcharging a Black Hole and Cosmic Censorship
We show that, contrary to a widespread belief, one can overcharge a near
extremal Reissner-Nordstrom black hole by throwing in a charged particle, as
long as the backreaction effects may be considered negligible. Furthermore, we
find that we can make the particle's classical radius, mass, and charge, as
well as the relative size of the backreaction terms arbitrarily small, by
adjusting the parameters corresponding to the particle appropriately. This
suggests that the question of cosmic censorship is still not wholly resolved
even in this simple scenario. We contrast this with attempting to overcharge a
black hole with a charged imploding shell, where we find that cosmic censorship
is upheld. We also briefly comment on a number of possible extensions.Comment: 26 pages, 3 figures, LaTe
Notes on Conformal Invisibility Devices
As a consequence of the wave nature of light, invisibility devices based on
isotropic media cannot be perfect. The principal distortions of invisibility
are due to reflections and time delays. Reflections can be made exponentially
small for devices that are large in comparison with the wavelength of light.
Time delays are unavoidable and will result in wave-front dislocations. This
paper considers invisibility devices based on optical conformal mapping. The
paper shows that the time delays do not depend on the directions and impact
parameters of incident light rays, although the refractive-index profile of any
conformal invisibility device is necessarily asymmetric. The distortions of
images are thus uniform, which reduces the risk of detection. The paper also
shows how the ideas of invisibility devices are connected to the transmutation
of force, the stereographic projection and Escheresque tilings of the plane
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