Calculation of the microcanonical temperature for the classical Bose field

The ergodic hypothesis asserts that a classical mechanical system will in time visit every available configuration in phase space. Thus, for an ergodic system, an ensemble average of a thermodynamic quantity can equally well be calculated by a time average over a sufficiently long period of dynamical evolution. In this paper we describe in detail how to calculate the temperature and chemical potential from the dynamics of a microcanonical classical field, using the particular example of the classical modes of a Bose-condensed gas. The accurate determination of these thermodynamics quantities is essential in measuring the shift of the critical temperature of a Bose gas due to non-perturbative many-body effects.Comment: revtex4, 10 pages, 1 figure. v2: updated to published version. Fuller discussion of numerical results, correction of some minor error

Have graben wall scarps accumulated sand and dust on Mars?

Grabens are linear fault bounded troughs that are extremely abundant on Mars (about 7000 cover the Western Hemisphere). Analysis of lunar and Martian grabens as well as analogous structures on Earth indicates that grabens form under extension when the crust is pulled apart. On Mars, topographic maps are not of sufficient resolution to measure graben wall slopes. Seismic shaking on Mars might be capable of reducing 60 deg fault scarps to an angle of repose. Some other process must be responsible for further reducing graben wall slopes. If the deposition of sand and dust along graben walls is responsible for their extremely low slopes, then a variety of implications are possible. Sand and/or dust movement and deposition is ubiquitous in grabens over most of Mars, as similar looking grabens are found over the entire Western Hemisphere and this requires a plentiful supply of sand or dust. If the material that accumulates is of low density and cohesion, attempts to traverse graben walls might be difficult. Rimless shallow depressions could be more effective sinks for sand and dust on Mars than has been realized

The detection of soft X-rays with charged coupled detectors

The characteristics of an ideal soft X-ray imaging detector are enumerated. Of recent technical developments the CCD or charge coupled device goes furthest to meeting these requirements. Several properties of CCDs are described with reference to experimental work and their application to practical instruments is reviewed

The effects of bilingualism on speakers who stutter during late childhood

Objectives: To examine stuttering by children speaking an alternative language exclusively (LE) or with English (BIL) and to study onset of stuttering, school performance and recovery rate relative to monolingual speakers who stutter (MONO). Design: Clinical referral sample with supplementary data obtained from speech recordings and interviews. Setting: South-East England, 1999–2007. Participants: Children aged 8–12 plus who stuttered (monolingual and bilingual) and fluent bilingual controls (FB). Main outcome measures: Participants’ stuttering history, SATS scores, measures of recovery or persistence of stuttering. Results: 69 (21.8%) of 317 children were bilingual. Of 38 children who used a language other than English at home, 36 (94.7%) stuttered in both languages. Fewer LE (15/38, 39.5%) than BIL (23/38, 60.5%) children stuttered at first referral to clinic, but more children in the fluent control sample were LE (28/38, 73.7%) than BIL (10/38, 26.3%). The association between stuttering and bilingual group (LE/BIL) was significant by x2 test; BIL speakers have more chance of stuttering than LE speakers. Age at stuttering onset and male/female ratio for LE, BIL and MONO speakers were similar (4 years 9 months, 4 years 10 months and 4 years 3 months, and 4.1:1, 4.75:1 and 4.43:1, respectively). Educational achievement was not affected by bilingualism relative to the MONO and FB groups. The recovery rate for the LE and MONO controls together (55%) was significantly higher by x2 test than for the BIL group (25%). Conclusions: BIL children had an increased risk of stuttering and a lower chance of recovery from stuttering than LE and MONO speakers

Development of a surface isolation estimation technique suitable for application of polar orbiting satellite data

A technique is developed for the estimation of total daily insolation on the basis of data derivable from operational polar-orbiting satellites. Although surface insolation and meteorological observations are used in the development, the algorithm is constrained in application by the infrequent daytime polar-orbiter coverage

Input description for Jameson's three-dimensional transonic airfoil analysis program

The input parameters are presented for a computer program which performs calculations for inviscid isentropic transonic flow over three dimensional airfoils with straight leading edges. The free stream Mach number is restricted only by the isentropic assumption. Weak shock waves are automatically located where they occur in the flow. The finite difference form of the full equation for the velocity potential is solved by the method of relaxation, after the flow exterior to the airfoil is mapped to the upper half plane

Advanced Centaur explicit guidance equation study Final report

Generalized equations and in-flight computer requirements for Centaur guidance and control and advanced mission plannin