Study of helium transfer technology for STICCR: Fluid management

The Space Infrared Telescope Facility (SIRTF) is a long life cryogenically cooled space based telescope for infrared astronomy from 2 to 700 microns currently under study and planned for launch in the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. Candidates are reviewed for a liquid management device to be used in the resupply of liquid helium, and for the selection of an appropriate candidate

The mission oriented terminal area simulation facility

The Mission Oriented Terminal Area Simulation (MOTAS) was developed to provide an ATC environment in which flight management and flight operations research studies can be conducted with a high degree of realism. This facility provides a flexible and comprehensive simulation of the airborne, ground-based and communication aspects of the airport terminal area environment. Major elements of the simulation are: an airport terminal area environment model, two air traffic controller stations, several aircraft models and simulator cockpits, four pseudo pilot stations, and a realistic air-ground communications network. MOTAS has been used for one study with the DC-9 simulator and a series of data link studies are planned in the near future

Decay of accelerated particles

We study how the decay properties of particles are changed by acceleration. It is shown that under the influence of acceleration (1) the lifetime of particles is modified and (2) new processes (like the decay of the proton) become possible. This is illustrated by considering scalar models for the decay of muons, pions, and protons. We discuss the close conceptual relation between these processes and the Unruh effect.Comment: Latex2e, 12 pages, 6 Postscript figures included with epsfig, to appear in Phys. Rev.

Preterm labour - Is Mycoplasma hominis involved?

Objective. To assess whether Mycoplasma hominis is associated with preterm labour in primigravidae  and multigravidae with previous midtrimester abortion or preterm labour.Design. Cohort analytical study. Setting. Tygerberg Hospital, a tertiary academic hospital in the Western Cape.Methods. Gram's stains were done on smears taken from the posterior vaginal fornix, at the first  antenatal visit, between 16 and 26 weeks' gestation, in primigravidae and multigravidae at risk for preterm labour. Cultures for M. hominis and other commonly occurring organisms were done ·from endocervical swabs taken at the same visit. The outcome of pregnancy in mothers with positive cultures for M. hominis was then compared with outcome in women with negative cultures.Outcome measures. Prevalence of Chlamydia trachomatis, Ureaplasma urealyticum, bacterial vaginosis and preterm delivery, birth weight and perinatal deaths.Results. Cultures for M. hominis were positive in 83 patients  (21 %) and negative in 312 (79%).  Significantly more mothers in the positive group (40%) delivered before 37 weeks' gestation than in the negative group (28%, P = 0.0313). Their babies weighed significantly less (2 669 g v. 2 864 g, P = 0.0141). The positive group was also associated with more alcohol use in pregnancy and fewer of them  were married. C. trachomatis was found in 18% of mothers in the positive group but in 8% of the negative group (P = 0.0082). U. urealyticum was cultured in 96% of mothers in the positive group in contrast to 81 % in the negative group (P = 0.001). Bacterial vaginosis was observed on 75% of mothers  with positive cultures for M. hominis but in 22% with negative cultures (P = 0.00001, odds ratio 10.21, 95% confidence interval: 5.63 - 18.65). Conclusion. Positive culture for M. hominis was associated with more preterm deliveries and also with a higher frequency of C. trachomatis, U. urealyticum and bacterial vaginosis

Structured evaluation of virtual environments for special-needs education

This paper describes the development of a structured approach to evaluate experiential and communication virtual learning environments (VLEs) designed specifically for use in the education of children with severe learning difficulties at the Shepherd special needs school in Nottingham, UK. Constructivist learning theory was used as a basis for the production of an evaluation framework, used to evaluate the design of three VLEs and how they were used by students with respect to this learning theory. From an observational field study of student-teacher pairs using the VLEs, 18 behaviour categories were identified as relevant to five of the seven constructivist principles defined by Jonassen (1994). Analysis of student-teacher behaviour was used to provide support for, or against, the constructivist principles. The results show that the three VLEs meet the constructivist principles in very different ways and recommendations for design modifications are put forward

Domain wall dynamics in expanding spaces

We study the effects on the dynamics of kinks due to expansions and contractions of the space. We show that the propagation velocity of the kink can be adiabatically tuned through slow expansions/contractions, while its width is given as a function of the velocity. We also analyze the case of fast expansions/contractions, where we are no longer on the adiabatic regime. In this case the kink moves more slowly after an expansion-contraction cycle as a consequence of loss of energy through radiation. All these effects are numerically studied in the nonlinear Klein-Gordon equations (both for the sine-Gordon and for the phi^4 potential), and they are also studied within the framework of the collective coordinate evolution equations for the width and the center of mass of the kink. These collective coordinate evolution equations are obtained with a procedure that allows us to consider even the case of large expansions/contractions.Comment: LaTeX, 18 pages, 2 figures, improved version to appear in Phys Rev

The Ursinus Weekly, May 8, 1916

Home team wins from Haverford • YMCA prospects for next year • Ursinus students hear good concert • Soldiers by consent • Tennis team trims Drexel • Among the colleges • The library • Joint meeting • Literary societies • 1913 take notice • Prominent marriage • Rutledge\u27s homer beats Lafayette • Ursinus reserves 9, Hill School 2d, 6https://digitalcommons.ursinus.edu/weekly/2628/thumbnail.jp

The Ursinus Weekly, May 1, 1916

Ursinus beaten by Swarthmore • Death claims member of Board • Good debate by Schaff Society • Soldiers by consent • Resolutions • Ursinus reserves win • Athletic notes • Ursinus defeats Gallaudet • Catholic University winshttps://digitalcommons.ursinus.edu/weekly/2627/thumbnail.jp

The Ursinus Weekly, March 19, 1917

Twenty-one games for Ursinus team • Events of the week • Basketball five has good season • Schaff prize essay: The social effects of the present war • Christian organizations • Ursinus College obituary record • Literary societies • Resolutions • College directory • Summary of 1916-17 basketball seasonhttps://digitalcommons.ursinus.edu/weekly/2586/thumbnail.jp