189 research outputs found
Quantum Fluctuations Driven Orientational Disordering: A Finite-Size Scaling Study
The orientational ordering transition is investigated in the quantum
generalization of the anisotropic-planar-rotor model in the low temperature
regime. The phase diagram of the model is first analyzed within the mean-field
approximation. This predicts at a phase transition from the ordered to
the disordered state when the strength of quantum fluctuations, characterized
by the rotational constant , exceeds a critical value . As a function of temperature, mean-field theory predicts a range of
values of where the system develops long-range order upon cooling, but
enters again into a disordered state at sufficiently low temperatures
(reentrance). The model is further studied by means of path integral Monte
Carlo simulations in combination with finite-size scaling techniques,
concentrating on the region of parameter space where reentrance is predicted to
occur. The phase diagram determined from the simulations does not seem to
exhibit reentrant behavior; at intermediate temperatures a pronounced increase
of short-range order is observed rather than a genuine long-range order.Comment: 27 pages, 8 figures, RevTe
The Physiology of Vasodilatation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68237/2/10.1177_000331976101200602.pd
Sensory and cognitive mechanisms of change detection in the context of speech
The aim of this study was to dissociate the contributions of memory-based (cognitive) and adaptation-based (sensory) mechanisms underlying deviance detection in the context of natural speech. Twenty healthy right-handed native speakers of English participated in an event-related design scan in which natural speech stimuli, /de:/ (“deh”) and /deI/ (“day”); (/te:/ (“teh”) and /teI/ (“tay”) served as standards and deviants within functional magnetic resonance imaging event-related “oddball” paradigm designed to elicit the mismatch negativity component. Thus, “oddball” blocks could involve either a word deviant (“day”) resulting in a “word advantage” effect, or a non-word deviant (“deh” or “tay”). We utilized an experimental protocol controlling for refractoriness similar to that used previously when deviance detection was studied in the context of tones. Results showed that the cognitive and sensory mechanisms of deviance detection were located in the anterior and posterior auditory cortices, respectively, as was previously found in the context of tones. The cognitive effect, that was most robust for the word deviant, diminished in the “oddball” condition. In addition, the results indicated that the lexical status of the speech stimulus interacts with acoustic factors exerting a top-down modulation of the extent to which novel sounds gain access to the subject’s awareness through memory-based processes. Thus, the more salient the deviant stimulus is the more likely it is to be released from the effects of adaptation exerted by the posterior auditory cortex
Cloud Computing As a Tool for Enhancing Ecological Goals?
Cloud computing has been introduced as a promising information technology (IT) that embodies not only economic advantages in terms of increased efficiency but also ecological gains through saving energy. The latter has become particularly important in view of the rising energy costs of IT. The present study analyzes whether necessary preconditions for accepting cloud computing as a new infrastructure, such as awareness and perceived net value, exist on the part of the users. The analysis is based on a combined research framework of the theory of reasoned action (TRA) and the technology acceptance model (TAM) in a cloud computing setting. Two consumer surveys, the one to elicit beliefs and the second to gain insight into the ranking of the variables, are employed. This study uses structural equation modeling (SEM) to evaluate the hypotheses. The results indicate support for the proposed research framework. Surprisingly however, the ecological factor does not play a role in forming cloud computing intentions, regardless of prior knowledge or experience. Empirical evidence of this study suggests increasing efforts for informing actual and potential users, particularly in respect to possible ecological advantages through applying the new IT infrastructure
- …