380 research outputs found
De novo large rare copy-number variations contribute to conotruncal heart disease in Chinese patients
published_or_final_versio
Spontaneous vortices in the formation of Bose-Einstein condensates
Phase transitions are ubiquitous in nature, ranging from protein folding and
denaturisation, to the superconductor-insulator quantum phase transition, to
the decoupling of forces in the early universe. Remarkably, phase transitions
can be arranged into universality classes, where systems having unrelated
microscopic physics exhibit identical scaling behaviour near the critical
point. Here we present an experimental and theoretical study of the
Bose-Einstein condensation phase transition of an atomic gas, focusing on one
prominent universal element of phase transition dynamics: the spontaneous
formation of topological defects during a quench through the transition. While
the microscopic dynamics of defect formation in phase transitions are generally
difficult to investigate, particularly for superfluid phase transitions,
Bose-Einstein condensates (BECs) offer unique experimental and theoretical
opportunities for probing such details. Although spontaneously formed vortices
in the condensation transition have been previously predicted to occur, our
results encompass the first experimental observations and statistical
characterisation of spontaneous vortex formation in the condensation
transition. Using microscopic theories that incorporate atomic interactions and
quantum and thermal fluctuations of a finite-temperature Bose gas, we simulate
condensation and observe vortex formation in close quantitative agreement with
our experimental results. Our studies provide further understanding of the
development of coherence in superfluids, and may allow for direct investigation
of universal phase-transition dynamics.Comment: 14 pages, 6 figures. Accepted for publication in Nature.
Supplementary movie files are available at
http://www.physics.uq.edu.au/people/mdavis/spontaneous_vortice
Speech Spectrum's Correlation with Speakers' Eysenck Personality Traits
The current study explored the correlation between speakers' Eysenck personality traits and speech spectrum parameters. Forty-six subjects completed the Eysenck Personality Questionnaire. They were instructed to verbally answer the questions shown on a computer screen and their responses were recorded by the computer. Spectrum parameters of /sh/ and /i/ were analyzed by Praat voice software. Formant frequencies of the consonant /sh/ in lying responses were significantly lower than that in truthful responses, whereas no difference existed on the vowel /i/ speech spectrum. The second formant bandwidth of the consonant /sh/ speech spectrum was significantly correlated with the personality traits of Psychoticism, Extraversion, and Neuroticism, and the correlation differed between truthful and lying responses, whereas the first formant frequency of the vowel /i/ speech spectrum was negatively correlated with Neuroticism in both response types. The results suggest that personality characteristics may be conveyed through the human voice, although the extent to which these effects are due to physiological differences in the organs associated with speech or to a general Pygmalion effect is yet unknown
An early warning method for agricultural products price spike based on artificial neural networks prediction
In general, the agricultural producing sector is affected by the diversity in supply, mostly from small companies, in addition to the rigidity of the demand, the territorial dispersion, the seasonality or the generation of employment related to the rural environment. These characteristics differentiate the agricultural sector from other economic sectors. On the other hand, the volatility of prices payed by producers, the high cost of raw materials, and the instability of both domestic and international markets are factors which have eroded the competitiveness and profitability of the agricultural sector. Because of the advance in technology, applications have been developed based on Artificial Neural Networks (ANN) which have helped the development of sales forecast on consumer products, improving the accuracy of traditional forecasting systems. This research uses the RNA to develop an early warning system for facing the increase in agricultural products, considering macro and micro economic variables and factors related to the seasons of the year
Testing the theory of immune selection in cancers that break the rules of transplantation
Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance
Dynamics of a Quantum Phase Transition and Relaxation to a Steady State
We review recent theoretical work on two closely related issues: excitation
of an isolated quantum condensed matter system driven adiabatically across a
continuous quantum phase transition or a gapless phase, and apparent relaxation
of an excited system after a sudden quench of a parameter in its Hamiltonian.
Accordingly the review is divided into two parts. The first part revolves
around a quantum version of the Kibble-Zurek mechanism including also phenomena
that go beyond this simple paradigm. What they have in common is that
excitation of a gapless many-body system scales with a power of the driving
rate. The second part attempts a systematic presentation of recent results and
conjectures on apparent relaxation of a pure state of an isolated quantum
many-body system after its excitation by a sudden quench. This research is
motivated in part by recent experimental developments in the physics of
ultracold atoms with potential applications in the adiabatic quantum state
preparation and quantum computation.Comment: 117 pages; review accepted in Advances in Physic
Appraisals, emotions and emotion regulation: An integrative approach
The present work aims to investigate the relation between appraisals, emotions, and emotion regulation strategies by creating a structural equation model which integrates these three aspects of the emotion process. To reach this aim, Italian students (N = 610) confronted with their high school diploma examination completed a questionnaire 3 weeks before the beginning of the exam. Results showed that they experienced primarily three types of emotions—anxiety/fear, frustration/powerlessness, positive emotions—which were related to specific appraisal profiles. Importantly, these appraisal profiles and emotions were associated with the use of different strategies for regulating emotions: anxiety/fear was associated with focusing on the exam, drug use, and an inability to distance oneself from the exam; frustration/powerlessness, with use of suppression, distancing, and drugs; positive emotion, with reappraisal and problem focused strategies. The effectiveness of these different strategies will be discussed
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