Requirements and Capabilities for Planetary Missions: Mariner Encke Ballistic Flyby 1980

This mission will provide a broad-based fast reconnaissance of comet Encke, building a data base for subsequent more detailed comet investigations, including rendezvous. After a 3 month flight, the spacecraft will encounter the comet at a nominal range of about 500 km. Flyby velocity will be 7 to 28 km/sec depending on choice of arrival data (0 to 35 days before Encke perihelion) and launch vehicle. The spacecraft will be similar to the MVM 73 spacecraft, with scan platform and 117 kbps encounter data rate, and designed to survive the thermal environment of 0.34 to 0.8 AU

Requirements and capabilities for planetary missions. Volume 2: Mars polar orbiter penetrator 1981

The Mars Polar Orbiter/Penetrator 1981 mission, intended to investigate the manner in which Mars has evolved, and which surveys its geochemistry, performs climatological investigations, and attempts to determine the planet's gravitational field, was described. The spacecraft, modified from the Viking Orbiter design, carries a new remote-sensing payload and six penetrators. The penetrators are released from a 2.46-h, 1000-km sun synchronous circular orbit and interrogated daily throughout the 2-year orbital mission. X-band telemetry is used to increase data return

International low back pain guidelines: A comparison of two research based models of care for the management of acute low back pain.

Evidence based guidelines for the management of acute low back pain (ALBP) have been formulated by numerous countries. There are discrepancies between guidelines regarding physiotherapy treatment. The aim of this study was to compare two research based models derived from international LBP guidelines. A single-blind randomised controlled trial was undertaken in a physiotherapy outpatients department. Subjects with ALBP were randomly allocated to an ‘assess/advise/treat’ group (n = 50) or an ‘assess/advise/wait’ group (n = 52). The primary outcome measure was the Roland and Morris Disability Questionnaire (RMDQ). Secondary outcome measures of pain (VAS, usual pain intensity) depressive symptoms (MZSRDS) somatic distress (MSPQ) anxiety (STAIS) quality of life (SF36) and general health (EuroQol) were also obtained. Outcomes were assessed at 6-weeks, 3-months and 6-months. At 6-weeks subjects in the assess/advise/treat group demonstrated less LBP related disability (p = 0.02) and depressive symptoms (p = 0.01), as well as better general health (p = 0.006, p = 0.05), vitality (p \u3c 0.001), social functioning (p = 0.004) and mental health (p = 0.002). At long-term assessment (3 and 6 months) subjects in the assess/advise/treat group were less distressed (p = 0.004), anxious (p = 0.01) and had fewer depressive symptoms (p = 0.001), as well as reporting better general health (p = 0.009, p = 0.05), emotional role (p = 0.03) and mental health (p = 0.04). Active physiotherapy produces better short-term outcomes than advice. Delaying treatment has no long-term consequences on pain or disability, but affects the development of psychosocial features

Direct simulation for a homogenous gas

A probabilistic analysis of the direct simulation of a homogeneous gas is given. A hierarchy of equations similar to the BBGKY hierarchy for the reduced probability densities is derived. By invoking the molecular chaos assumption, an equation similar to the Boltzmann equation for the single particle probability density and the corresponding H-theorem is derived

Microrheological Characterisation of Anisotropic Materials

We describe the measurement of anisotropic viscoelastic moduli in complex soft materials, such as biopolymer gels, via video particle tracking microrheology of colloid tracer particles. The use of a correlation tensor to find the axes of maximum anisotropy, and hence the mechanical director, is described. The moduli of an aligned DNA gel are reported, as a test of the technique; this may have implications for high DNA concentrations in vivo. We also discuss the errors in microrheological measurement, and describe the use of frequency space filtering to improve displacement resolution, and hence probe these typically high modulus materials.Comment: 5 pages, 5 figures. Replaced after refereeing/ improvement. Main results are the same. The final, published version of the paper is here http://link.aps.org/abstract/PRE/v73/e03190

Gaussian approximation for finitely extensible bead-spring chains with hydrodynamic interaction

The Gaussian Approximation, proposed originally by Ottinger [J. Chem. Phys., 90 (1) : 463-473, 1989] to account for the influence of fluctuations in hydrodynamic interactions in Rouse chains, is adapted here to derive a new mean-field approximation for the FENE spring force. This "FENE-PG" force law approximately accounts for spring-force fluctuations, which are neglected in the widely used FENE-P approximation. The Gaussian Approximation for hydrodynamic interactions is combined with the FENE-P and FENE-PG spring force approximations to obtain approximate models for finitely-extensible bead-spring chains with hydrodynamic interactions. The closed set of ODE's governing the evolution of the second-moments of the configurational probability distribution in the approximate models are used to generate predictions of rheological properties in steady and unsteady shear and uniaxial extensional flows, which are found to be in good agreement with the exact results obtained with Brownian dynamics simulations. In particular, predictions of coil-stretch hysteresis are in quantitative agreement with simulations' results. Additional simplifying diagonalization-of-normal-modes assumptions are found to lead to considerable savings in computation time, without significant loss in accuracy.Comment: 26 pages, 17 figures, 2 tables, 75 numbered equations, 1 appendix with 10 numbered equations Submitted to J. Chem. Phys. on 6 February 200