5,103 research outputs found
Symmetry breaking and unconventional charge ordering in single crystal NaRuO
The interplay of charge, spin, and lattice degrees of freedom in matter leads
to various forms of ordered states through phase transitions. An important
subclass of these phenomena of complex materials is charge ordering (CO),
mainly driven by mixed-valence states. We discovered by combining the results
of electrical resistivity (), specific heat, susceptibility
(\textit{T}), and single crystal x-ray diffraction (SC-XRD) that
NaRuO with the monoclinic tunnel type lattice (space group
2/) exhibits an unconventional CO at room temperature while retaining
metallicity. The temperature-dependent SC-XRD results show successive phase
transitions with super-lattice reflections at \textbf{q}=(0, ,
0) and \textbf{q}=(0, , ) below
(365 K) and only at \textbf{q}=(0, , 0) between
and (630 K). We interpreted these as an
evidence for the formation of an unconventional CO. It reveals a strong
first-order phase transition in the electrical resistivity at
(cooling) = 345 K and (heating) = 365 K. We argue that the
origin of the phase transition is due to the localized 4 Ru-electrons. The
results of our finding reveal an unique example of Ru/Ru mixed
valance heavy \textit{d} ions.Comment: 10 pages, 9 figure
The impact of multimodal collaborative virtual environments on learning: A gamified online debate
Online learning platforms are integrated systems designed to provide students and teachers with information, tools and resources to facilitate and enhance the delivery and management of learning. In recent years platform designers have introduced gamification and multimodal interaction as ways to make online courses more engaging and immersive. Current Web-based platforms provide a limited degree of immersion in learning experiences, thereby diminishing potential learning impact. To improve immersion, it is necessary to stimulate some or all the human senses by engaging users in an environment that perceptually surrounds them and allows intuitive and rich interaction with other users and its content. Learning in these collaborative virtual environments (CVEs) can be aided by increasing motivation and engagement through the gamification of the educational task. This rich interaction that combines multimodal stimulation and gamification of the learning experience has the potential to draw students into the learning experience and improve learning outcomes. This paper presents the results of an experimental study designed to evaluate the impact of multimodal real-time interaction on user experience and learning of gamified educational tasks completed in a CVE. Secondary school teachers and students participated in the study. The multimodal CVE is an accurate reconstruction of the European Parliament in Brussels, developed using the REVERIE (Real and Virtual Engagement In Realistic Immersive Environment) framework. In the study, we compared the impact of the VR parliament to a non-multimodal control (an educational platform called Edu-Simulation) for the same educational tasks. Our results show that the multimodal CVE improves student learning performance and aspects of subjective experience when compared to the non-multimodal control. More specifically it resulted in a more positive effect on the ability of the students to generate ideas compared to a non-multimodal control. It also facilitated a sense of presence (strong emotional and a degree of spatial) for students in the VE. The paper concludes with a discussion of future work that focusses on combining the best features of both systems in a hybrid system to increase its educational impact and evaluate the prototype in real-world educational scenarios
Postfledging Survival, Movements, and Dispersal of Ring Ouzels (Turdus torquatus)
We thank Invercauld Estate for cooperation with access to Glen Clunie. S. Redpath, J. Wilson, and S. Roos provided valuable comments on the manuscript. This study was funded by the Royal Society for the Protection of Birds, Scottish Natural Heritage, and the Cairngorms National Park Authority. J.L.L. was supported by the Natural Environment Research Council.Peer reviewedPublisher PD
Estudi de la brioflora dels Ports de Beseit
A catalog of the 186 bryophytic taxa found in the calcareous mountain area of the Ports de Beseit is given, together with a short description of the bryological vegetation, and comments on interesting species such as Acaulon dertosense, Frullania muscicolu, Brachythecium olympicum, Rhynchostegiella compacta, Tortula solmsii, etc. Chorological and ecological spectra are also given.Presentem el catàleg dels 186 taxons briofítics trobats als Ports de Beseit, junt amb una succinta descripció de la vegetació briofítica i comentaris sobre certes especies interessants, com ara Acaulon dertosense, Frullania muscicola, Brachythecium olympicum, Rhynchostegiella compacta, Tortula solmsii, etc. Donem també els espectres corologies i de diversos factors ecologies
Mindfulness facets, trait emotional intelligence, emotional distress, and multiple health behaviors: A serial two-mediator model.
In the present study, we tested a serial mindfulness facets-trait emotional intelligence (TEI)-emotional distress-multiple health behaviors mediation model in a sample of N = 427 German-speaking occupational therapists. The mindfulness facets-TEI-emotional distress section of the mediation model revealed partial mediation for the mindfulness facets Act with awareness (Act/Aware) and Accept without judgment (Accept); inconsistent mediation was found for the Describe facet. The serial two-mediator model included three mediational pathways that may link each of the four mindfulness facets with multiple health behaviors. Eight out of 12 indirect effects reached significance and fully mediated the links between Act/Aware and Describe to multiple health behaviors; partial mediation was found for Accept. The mindfulness facet Observe was most relevant for multiple health behaviors, but its relation was not amenable to mediation. Implications of the findings will be discussed
Double-detonation sub-Chandrasekhar supernovae: synthetic observables for minimum helium shell mass models
Abridged. In the double detonation scenario for Type Ia supernovae (SNe Ia) a
detonation initiates in a shell of He-rich material accreted from a companion
star by a sub-Chandrasekhar-mass White Dwarf (WD). This shell detonation drives
a shock front into the carbon-oxygen (C/O) WD that triggers a secondary
detonation in the core. The core detonation results in a complete disruption of
the WD. Earlier studies concluded that this scenario has difficulties in
accounting for the observed properties of SNe Ia since the explosion ejecta are
surrounded by the products of explosive He burning in the shell. Recently, it
was proposed that detonations might be possible for much less massive He shells
than previously assumed. Moreover, it was shown that even detonations of these
minimum He shell masses robustly trigger detonations of the C/O core. Here we
present time-dependent multi-wavelength radiative transfer calculations for
models with minimum He shell mass and derive synthetic observables for both the
optical and {\gamma}-ray spectral regions. These differ strongly from those
found in earlier simulations of sub-Chandrasekhar-mass explosions in which more
massive He shells were considered. Our models predict light curves which cover
both the range of brightnesses and the rise and decline times of observed SNe
Ia. However, their colours and spectra do not match the observations. In
particular, their B-V colours are generally too red. We show that this
discrepancy is mainly due to the composition of the burning products of the He
shell of our models which contain significant amounts of Ti and Cr. Using a toy
model, we also show that the burning products of the He shell depend crucially
on its initial composition. This leads us to conclude that good agreement
between sub-Chandrasekhar-mass explosions and observed SNe Ia may still be
feasible but further study of the shell properties is required.Comment: 17 pages, 13 figures. Accepted for publication by Ap
Moments of spectral functions: Monte Carlo evaluation and verification
The subject of the present study is the Monte Carlo path-integral evaluation
of the moments of spectral functions. Such moments can be computed by formal
differentiation of certain estimating functionals that are
infinitely-differentiable against time whenever the potential function is
arbitrarily smooth. Here, I demonstrate that the numerical differentiation of
the estimating functionals can be more successfully implemented by means of
pseudospectral methods (e.g., exact differentiation of a Chebyshev polynomial
interpolant), which utilize information from the entire interval . The algorithmic detail that leads to robust numerical
approximations is the fact that the path integral action and not the actual
estimating functional are interpolated. Although the resulting approximation to
the estimating functional is non-linear, the derivatives can be computed from
it in a fast and stable way by contour integration in the complex plane, with
the help of the Cauchy integral formula (e.g., by Lyness' method). An
interesting aspect of the present development is that Hamburger's conditions
for a finite sequence of numbers to be a moment sequence provide the necessary
and sufficient criteria for the computed data to be compatible with the
existence of an inversion algorithm. Finally, the issue of appearance of the
sign problem in the computation of moments, albeit in a milder form than for
other quantities, is addressed.Comment: 13 pages, 2 figure
Time-stepping beyond CFL: a locally one-dimensional scheme for acoustic wave propagation
In this abstract, we present a case study in the application of a time-stepping method, unconstrained by the CFL condition, for computational acoustic wave propagation in the context of full waveform inversion. The numerical scheme is a locally one-dimensional (LOD) variant of alternating dimension implicit (ADI) method. The LOD method has a maximum time step that is restricted only by the Nyquist sampling rate. The advantage over traditional explicit time-stepping methods occurs in the presence of high contrast media, low frequencies, and steep, narrow perfectly matched layers (PML). The main technical point of the note, from a numerical analysis perspective, is that the LOD scheme is adapted to the presence of a PML. A complexity study is presented and an application to full waveform inversion is shown.National Science Foundation (U.S.); Alfred P. Sloan Foundatio
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