Universal efficiency at optimal work with Bayesian statistics

If the work per cycle of a quantum heat engine is averaged over an appropriate prior distribution for an external parameter $a$, the work becomes optimal at Curzon-Ahlborn efficiency. More general priors of the form $\Pi(a) \propto 1/a^{\gamma}$ yield optimal work at an efficiency which stays close to CA value, in particular near equilibrium the efficiency scales as one-half of the Carnot value. This feature is analogous to the one recently observed in literature for certain models of finite-time thermodynamics. Further, the use of Bayes' theorem implies that the work estimated with posterior probabilities also bears close analogy with the classical formula. These findings suggest that the notion of prior information can be used to reveal thermodynamic features in quantum systems, thus pointing to a new connection between thermodynamic behavior and the concept of information.Comment: revtex4, 5 pages, abstract changed and presentation improved; results unchanged. New result with Bayes Theorem adde

Expected Behavior of Quantum Thermodynamic Machines with Prior Information

We estimate the expected behavior of a quantum model of heat engine when we have incomplete information about external macroscopic parameters, like magnetic field controlling the intrinsic energy scales of the working medium. We explicitly derive the prior probability distribution for these unknown parameters, $a_i, (i=1,2)$. Based on a few simple assumptions, the prior is found to be of the form $\Pi(a_i) \propto 1/a_i$. By calculating the expected values of various physical quantities related to this engine, we find that the expected behavior of the quantum model exhibits thermodynamic-like features. This leads us to a surprising proposal that incomplete information quantified as appropriate prior distribution can lead us to expect classical thermodynamic behavior in quantum models.Comment: Revtex, 13 pages, 3 figures, revised version, new results added, accepted for Phys. Rev.

PC-based aviation training devices (PCATDs): research, development and certification

This paper examines the development of two PCATD’s (one helicopter, one fixed-wing) and their eventual certification by CAA. Certification has demonstrated the potential these devices have for aviation training in New Zealand. Traditionally FTD‘s and PCATD’s have been sourced from foreign companies, and they represent a considerable financial investment for large flying training organisations. The procurement of these simulator types is generally beyond the financial resources of most small to medium sized flying schools. Aviation training in NZ is facing significant financial constraints as well as an increasing demand to simulate complex glass cockpit systems that are now installed in most new General Aviation (GA) aircraft. The development, utilisation and certification of this type of PCATD technology could solve these difficult challenges

Development of a laser Doppler system for the detection and monitoring of atmospheric disturbances

A Scanning Laser Doppler Velocimeter System (SLDVS) capable of detecting and monitoring atmospheric disturbances, including wake vortices of landing aircraft and vertical wind profiles in the atmosphere was developed. The SLDVS is a focused, continuous wave, CO2 system that determines the line-of-sight velocities of particles in the focal volume by measuring the Doppler shift created by these particles. At present, the SLDVS is designed to have a range coverage of approximately 2000 ft with a vertical angle coverage of approximately 60 deg. It is also designed to detect Doppler velocities of up to 200 ft/sec with a velocity resolution of approximately 1.8 ft/sec. A complete velocity spectrum is provided by the SLDVS at each point in space at which it is focused. The overall operation and performance of the system and the description of its individual components and data handling capabilities were given

Estimation of Upper Limits Using a Poisson Statistic

Bayesian, classical, and extended maximum likelihood approaches to estimation of upper limits in experiments with small numbers of signal events are surveyed. The discussion covers only experiments whose outcomes are well described by a Poisson statistic. A new approach, based on the statistical significance of a signal rather than on the number of events in the signal region, is proposed. A toy model and an example of a recent search for the lepton number violating decay $\tau\to\mu\gamma$ are used to illustrate application of the discussed techniques.Comment: 24 pages, 7 figure

The Oral Background of Byzantine Popular Poetry

The popular poetry of Byzantium first appears in the form of consistent surviving texts of some size in the middle of the twelfth century, at the courts of the emperors John Komnenos (1118-1143) and Manuel Komnenos (1143-1180).1 Little or no such poetry seems to survive from the thirteenth century, when Byzantine energies were occupied in the reconquest of Constantinople and other parts of the empire from the forces of the Fourth Crusade. The next preserved examples seem to date from early in the fourteenth century, and the popular poetic tradition then continues through to the end of Byzantium in 1453 and beyond. Insofar as evidence permits us to speak about the places in which this material was composed and written down, it seems that the westernruled states surviving from the Crusades on Greek lands were at least as fertile ground for its production as the area ruled by Byzantium, under the last dynasty of the Palaiologoi. The total volume is not large, but it covers a number of genres. We shall discuss in the conclusion of this paper the difficult question of the continuity of this tradition in Greece under Turkish rule.--Page 504.Elizabeth and Michael Jeffreys (University of Sydney) often work as a team in their investigations of Byzantine popular poetry, studies which regularly treat the oral tradition out of which these works emerged. Some of their numerous articles in this field are gathered together in Popular Literature in Byzantium (1983)

Dispoetics

Produced by Hawai'i University Affiliated Program on Disabilities, University of Hawai'i at Manoa, Honolulu, Hawai'i, Frank Sawyer School of Management, Suffolk University, Boston, Massachusetts, and School of Social Sciences, The University of Texas at Dallas, Richardson, Texas for The Society for Disability Studies

Nitrogen metabolism of the isolated tissues of the rat

Little study has been devoted to the anabolic aspects of nitrogen metabolism in animals. The reason, of course, has been the difficulty of obtaining experimental conditions in which these can be observed, measured, and analyzed. The experiments of Krebs and Henseleit (1) on the formation of urea from ammonia with Warburg’s method of surviving slices of liver suggested that this method might be useful in a direct attack on a number of problems of nitrogen anabolism in animals; i.e., it might be possible to observe reactions in which there is a gain in free energy. It appears that for these reactions the intact cell structure is necessary

Towards testing interacting cosmology by distant type Ia supernovae

We investigate the possibility of testing cosmological models with interaction between matter and energy sector. We assume the standard FRW model while the so called energy conservation condition is interpreted locally in terms of energy transfer. We analyze two forms of dark energy sectors: the cosmological constant and phantom field. We find a simple exact solution of the models in which energy transfer is described by a Cardassian like term in the relation of $H^{2}(z)$, where $H$ is Hubble's function and $z$ is redshift. The considered models have two additional parameters $(\Omega_{\text{int}},n)$ (apart the parameters of the $\Lambda$CDM model) which can be tested using SNIa data. In the estimation of the model parameters Riess et al.'s sample is used. We also confront the quality of statistical fits for both the $\Lambda$CDM model and the interacting models with the help of the Akaike and Bayesian informative criteria. Our conclusion from standard best fit method is that the interacting models explains the acceleration of the Universe better but they give rise to a universe with high matter density. However, using the tools of information criteria we find that the two new parameters play an insufficient role in improving the fit to SNIa data and the standard $\Lambda$CDM model is still preferred. We conclude that high precision detection of high redshift supernovae could supply data capable of justifying adoption of new parameters.Comment: RevTeX4, 14 pages, 7 figure