1,500 research outputs found
Music emotion classification by audio signal analysis: analysis of self-selected music during game play
Acoustic analysis and mood classification of pain-relieving music
Listening to preferred music (that which is chosen by the participant) has been shown to be effective in mitigating the effects of pain when compared to silence and a variety of distraction techniques. The wide range of genre, tempo, and structure in music chosen by participants in studies utilizing experimentally induced pain has led to the assertion that structure does not play a significant role, rather listening to preferred music renders the music functionally equivalent as regards its effect upon pain perception. This study addresses this assumption and performs detailed analysis of a selection of music chosen from three pain studies. Music analysis showed significant correlation between timbral and tonal aspects of music and measurements of pain tolerance and perceived pain intensity. Mood classification was performed using a hierarchical Gaussian Mixture Model, which indicated the majority of the chosen music expressed contentment. The results suggest that in addition to personal preference, associations with music and the listening context, emotion expressed by music, as defined by its acoustical content, is important to enhancing emotional engagement with music and therefore enhances the level of pain reduction and tolerance
A simple example of "Quantum Darwinism": Redundant information storage in many-spin environments
As quantum information science approaches the goal of constructing quantum
computers, understanding loss of information through decoherence becomes
increasingly important. The information about a system that can be obtained
from its environment can facilitate quantum control and error correction.
Moreover, observers gain most of their information indirectly, by monitoring
(primarily photon) environments of the "objects of interest." Exactly how this
information is inscribed in the environment is essential for the emergence of
"the classical" from the quantum substrate. In this paper, we examine how
many-qubit (or many-spin) environments can store information about a single
system. The information lost to the environment can be stored redundantly, or
it can be encoded in entangled modes of the environment. We go on to show that
randomly chosen states of the environment almost always encode the information
so that an observer must capture a majority of the environment to deduce the
system's state. Conversely, in the states produced by a typical decoherence
process, information about a particular observable of the system is stored
redundantly. This selective proliferation of "the fittest information" (known
as Quantum Darwinism) plays a key role in choosing the preferred, effectively
classical observables of macroscopic systems. The developing appreciation that
the environment functions not just as a garbage dump, but as a communication
channel, is extending our understanding of the environment's role in the
quantum-classical transition beyond the traditional paradigm of decoherence.Comment: 21 pages, 6 figures, RevTex 4. Submitted to Foundations of Physics
(Asher Peres Festschrift
Hyphal Orientation of Candida albicans Is Regulated by a Calcium-Dependent Mechanism
SummaryEukaryotic cells from fungal hyphae to neurites that grow by polarized extension must coordinate cell growth and cell orientation to enable them to exhibit growth tropisms and to respond to relevant environmental cues. Such cells generally maintain a tip-high Ca2+ cytoplasmic gradient, which is correlated with their ability to exhibit polarized tip growth and to respond to growth-directing extracellular signals [1â5]. In yeast and other fungi, the polarisome, exocyst, Arp2/3, and Spitzenkörper protein complexes collectively orchestrate tip growth and cell polarity, but it is not clear whether these molecular complexes also regulate cell orientation or whether they are influenced by cytoplasmic Ca2+ gradients. Hyphae of the human pathogenic fungus Candida albicans reorient their growth axis in response to underlying surface topography (thigmotropism) [6] and imposed electric fields (galvanotropism) [7]. The establishment and maintenance of directional growth in relation to these environmental cues was Ca2+ dependent. Tropisms were attenuated in media containing low Ca2+, or calcium-channel blockers, and in mutants where calcium channels or elements of the calcium signaling pathway were deleted. Therefore galvanotropism and thigmotropism may both be mediated by localized Ca2+ influx at sites of polarized growth via Ca2+ channels that are activated by appropriate environmental signals
Spatial Metrics of Tumour Vascular Organisation Predict Radiation Efficacy in a Computational Model
Intratumoural heterogeneity is known to contribute to poor therapeutic response. Variations in oxygen tension in particular have been correlated with changes in radiation response in vitro and at the clinical scale with overall survival. Heterogeneity at the microscopic scale in tumour blood vessel architecture has been described, and is one source of the underlying variations in oxygen tension. We seek to determine whether histologic scale measures of the erratic distribution of blood vessels within a tumour can be used to predict differing radiation response. Using a two-dimensional hybrid cellular automaton model of tumour growth, we evaluate the effect of vessel distribution on cell survival outcomes of simulated radiation therapy. Using the standard equations for the oxygen enhancement ratio for cell survival probability under differing oxygen tensions, we calculate average radiation effect over a range of different vessel densities and organisations. We go on to quantify the vessel distribution heterogeneity and measure spatial organization using Ripley's L function, a measure designed to detect deviations from complete spatial randomness. We find that under differing regimes of vessel density the correlation coefficient between the measure of spatial organization and radiation effect changes sign. This provides not only a useful way to understand the differences seen in radiation effect for tissues based on vessel architecture, but also an alternate explanation for the vessel normalization hypothesis
A Family of Exact, Analytic Time Dependent Wave Packet Solutions to a Nonlinear Schroedinger Equation
We obtain time dependent -Gaussian wave-packet solutions to a non linear
Schr\"odinger equation recently advanced by Nobre, Rego-Montero and Tsallis
(NRT) [Phys. Rev. Lett. 106 (2011) 10601]. The NRT non-linear equation admits
plane wave-like solutions (-plane waves) compatible with the celebrated de
Broglie relations connecting wave number and frequency, respectively, with
energy and momentum. The NRT equation, inspired in the -generalized
thermostatistical formalism, is characterized by a parameter , and in the
limit reduces to the standard, linear Schr\"odinger equation. The
-Gaussian solutions to the NRT equation investigated here admit as a
particular instance the previously known -plane wave solutions. The present
work thus extends the range of possible processes yielded by the NRT dynamics
that admit an analytical, exact treatment. In the limit the
-Gaussian solutions correspond to the Gaussian wave packet solutions to the
free particle linear Schr\"odinger equation. In the present work we also show
that there are other families of nonlinear Schr\"odinger-like equations,
besides the NRT one, exhibiting a dynamics compatible with the de Broglie
relations. Remarkably, however, the existence of time dependent Gaussian-like
wave packet solutions is a unique feature of the NRT equation not shared by the
aforementioned, more general, families of nonlinear evolution equations
Short-range hunters: exploring the function and constraints of water shooting in dwarf gouramis
Ballistic predation is a rare foraging adaptation: in fishes, most attention has focused on a single genus, the archerfish, known to manipulate water to shoot down prey above the water surface. However, several gourami species also exhibit apparently similar âshootingâ behaviour, spitting water up to 5â
cm above the surface. In a series of experiments, we explored the shooting behaviour and aspects of its significance as a foraging ability in the dwarf gourami (Trichogaster lalius). We investigated sex differences in shooting abilities to determine whether gourami shooting is related to the sex-specific bubble nest manufacture where males mix air and water at the surface to form bubbles. We found that, actually, both sexes were equally able to shoot and could learn to shoot a novel target. In a second experiment, we presented untrained gouramis with opportunities to shoot at live prey and found they successfully shot down both fruit flies and crickets. Finally, we explored the effect of target height on shooting performance to establish potential constraints of shooting as a foraging ability. The frequency of attempted shots and success of hitting targets decreased with height, whereas latency to shoot increased. We also observed that repeatable individual differences account for variation in these measures of shooting performance. Together, our results provide evidence that gourami shooting has a foraging function analogous to that of archerfish. Gourami shooting may serve as an example of convergent evolution and provide opportunities for comparative studies into the, as yet unexplored, ecology and evolution of shooting in fishes.Peer reviewe
Discrete Breathers in Two-Dimensional Anisotropic Nonlinear Schrodinger lattices
We study the structure and stability of discrete breathers (both pinned and
mobile) in two-dimensional nonlinear anisotropic Schrodinger lattices. Starting
from a set of identical one-dimensional systems we develop the continuation of
the localized pulses from the weakly coupled regime (strongly anisotropic) to
the homogeneous one (isotropic). Mobile discrete breathers are seen to be a
superposition of a localized mobile core and an extended background of
two-dimensional nonlinear plane waves. This structure is in agreement with
previous results on onedimensional breather mobility. The study of the
stability of both pinned and mobile solutions is performed using standard
Floquet analysis. Regimes of quasi-collapse are found for both types of
solutions, while another kind of instability (responsible for the discrete
breather fission) is found for mobile solutions. The development of such
instabilities is studied, examining typical trajectories on the unstable
nonlinear manifold.Comment: 13 pages, 9 figure
Limits on the gravity wave contribution to microwave anisotropies
We present limits on the fraction of large angle microwave anisotropies which
could come from tensor perturbations. We use the COBE results as well as
smaller scale CMB observations, measurements of galaxy correlations, abundances
of galaxy clusters, and Lyman alpha absorption cloud statistics. Our aim is to
provide conservative limits on the tensor-to-scalar ratio for standard
inflationary models. For power-law inflation, for example, we find T/S<0.52 at
95% confidence, with a similar constraint for phi^p potentials. However, for
models with tensor amplitude unrelated to the scalar spectral index it is still
currently possible to have T/S>1.Comment: 23 pages, 7 figures, accepted for publication in Phys. Rev. D.
Calculations extended to blue spectral index, Fig. 6 added, discussion of
results expande
Activation of the heat shock transcription factor Hsf1 is essential for the full virulence of the fungal pathogen Candida albicans
Peer reviewedPublisher PD
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