Milestone report TCTP application to the SSME hydrogen system analysis

The Transient Cryogen Transfer Computer Program (TCTP) developed and verified for LOX systems by analyses of Skylab S-1B stage loading data from John F. Kennedy Space Center launches was extended to include hydrogen as the working fluid. The feasibility of incorporating TCTP into the space shuttle main engine dynamic model was studied. The program applications are documented

New South Wales Vegetation classification and Assessment: Part 3, plant communities of the NSW Brigalow Belt South, Nandewar and west New England Bioregions and update of NSW Western Plains and South-western Slopes plant communities, Version 3 of the NSWVCA database

This fourth paper in the NSW Vegetation Classification and Assessment series covers the Brigalow Belt South-/1(BBS) and Nandewar (NAN) Bioregions and the western half of the New England Bioregion (NET), an area of 9.3 million hectares being 11.6% of NSW. It completes the NSWVCA coverage for the Border Rivers-Gwydir and Namoi CMA areas and records plant communities in the Central West and Hunter–Central Rivers CMA areas. In total, 585 plant communities are now classified in the NSWVCA covering 11.5 of the 18 Bioregions in NSW (78% of the State). Of these 226 communities are in the NSW Western Plains and 416 are in the NSW Western Slopes. 315 plant communities are classified in the BBS, NAN and west-NET Bioregions including 267 new descriptions since Version 2 was published in 2008. Descriptions of the 315 communities are provided in a 919 page report on the DVD accompanying this paper along with updated reports on other inland NSW bioregions and nine Catchment Management Authority areas fully or partly classified in the NSWVCA to date. A read-only version of Version 3 of the NSWVCA database is on the DVD for use on personal computers. A feature of the BBS and NAN Bioregions is the array of ironbark and bloodwood Eucalyptusdominated shrubby woodlands on sandstone and acid volcanic substrates extending from Dubbo to Queensland. This includes iconic natural areas such as Warrumbungle and Mount Kaputar National Parks and the 500,000 ha Pilliga Scrub forests. Large expanses of basalt-derived soils support grassy box woodland and native grasslands including those on the Liverpool Plains; near Moree; and around Inverell, most of which are cleared and threatened. Wetlands occur on sodic soils near Yetman and in large clay gilgais in the Pilliga region. Sedgelands are rare but occupy impeded creeks. Aeolian lunettes occur at Narran Lake and near Gilgandra. Areas of deep sand contain Allocasuarina, eucalypt mallee and Melaleuca uncinata heath. Tall grassy or ferny open forests occur on mountain ranges above 1000m elevation in the New England Bioregion and on the Liverpool Range while grassy box woodlands occupy lower elevations with lower rainfall and higher temperatures. The vegetation classification and assessment is based on over 100 published and unpublished vegetation surveys and map unit descriptions, expert advice, extra plot sampling and data analysis and over 25 000 km of road traverse with field checking at 805 sites. Key sources of data included floristic analyses produced in western regional forest assessments in the BBS and NAN Bioregions, floristic analyses in over 60 surveys of conservation reserves and analysis of plot data in the western NET Bioregion and covering parts of the Namoi and Border Rivers- Gwydir CMA areas. Approximately 60% of the woody native vegetation in the study area has been cleared resulting in large areas of “derived” native grasslands. As of June 2010, 7% of the area was in 136 protected areas and 127 of the 315 plant communities were assessed to be adequately protected in reserves. Using the NSWVCA database threat criteria, 15 plant communities were assessed as being Critically Endangered, 59 Endangered, 60 Vulnerable, 99 Near Threatened and 82 Least Concern. 61 of these communities are assessed as part of NSW or Commonwealth-listed Threatened Ecological Communities. Current threats include expanding dryland and irrigated cropping on alluvial plains, floodplains and gently undulating topography at lower elevations; over-grazing of steep hills; altered water tables and flooding regimes; localized mining; and the spread of exotic species, notably Coolatai Grass (Hyparrhenia hirta)

Laserlight visual cueing device for freezing of gait in Parkinson's disease: a case study of the biomechanics involved

AbstractBackground: Freezing of gait (FOG) is a serious gait disorder affecting up to two-thirds of people with Parkinson's disease (PD). Cueing has been explored as a method of generating motor execution using visual transverse lines on the floor. However, the impact of a laser light visual cue remains unclear. Objective: To determine the biomechanical effect of a laser cane on FOG in a participant with PD compared to a healthy age- and gender-matched control. Methods: The participant with PD and healthy control were given a task of initiating gait from standing. Electromyography (EMG) data were collected from the tibialis anterior (TA) and the medial gastrocnemius (GS) muscles using an 8-channel system. A 10-camera system (Qualisys) recorded movement in 6 degrees of freedom and a calibrated anatomical system technique was used to construct a full body model. Center of mass (COM) and center of pressure (COP) were the main outcome measures. Results: The uncued condition showed that separation of COM and COP took longer and was of smaller magnitude than the cued condition. EMG activity revealed prolonged activation of GS, with little to no TA activity. The cued condition showed earlier COM and COP separation. There was reduced fluctuation in GS, with abnormal, early bursts of TA activity. Step length improved in the cued condition compared to the uncued condition. Conclusion: Laserlight visual cueing improved step length beyond a non-cued condition for this patient indicating improved posture and muscle control

Direct and indirect orthotic management of medial compartment osteoarthritis of the knee

Osteoarthritis (OA) is a painful condition and affects approximately 80% of individuals by the age of 55 [1], with knee OA occurring two times more frequently than OA of the hand or hip [2].The condition is more prevalent in the medial compartment and restricts the daily lives of individuals due to pain and a lack of functional independence. Patients with medial compartment osteoarthritis often have a varus alignment, with the mechanical axis and load bearing passing through this compartment with a greater adduction moment leading to greater pain and progression of osteoarthritis [3]. Surgery for the condition is possible although in some cases, particularly younger patients or those not yet requiring surgery, clinical management remains a challenge. Before surgery is considered, however, conservative management is advocated, though no one treatment has been shown to be most effective, and there are few quality biomechanical or clinical studies. Of the conservative approaches the principal orthotic treatments are valgus knee braces and laterally wedged foot inlays. Studies of knee valgus bracing have consistently demonstrated an associated decreased pain and improved function [4], and greater confidence [5]. A laterally wedged foot inlay has a thicker lateral border and applies a valgus moment to the heel. It is theorised that by changing the position of the ankle and subtalar joints during weight-bearing [6] the lateral wedges may apply a valgus moment across the knee as well as the rearfoot, with the assumed reduction on load in the medial knee compartment [7]. However, there has been no study to directly compare these orthotic treatments in the same study. The aim of this research is to investigate the efficacy of valgus knee braces and laterally wedged foot inlays in reducing the varus knee moment

Distances of Stars by mean of the Phase-lag Method

Variable OH/IR stars are Asymptotic Giant Branch (AGB) stars with an optically thick circumstellar envelope that emit strong OH 1612 MHz emission. They are commonly observed throughout the Galaxy but also in the LMC and SMC. Hence, the precise inference of the distances of these stars will ultimately result in better constraints on their mass range in different metallicity environments. Through a multi-year long-term monitoring program at the Nancay Radio telescope (NRT) and a complementary high-sensitivity mapping campaign at the eMERLIN and JVLA to measure precisely the angular diameter of the envelopes, we have been re-exploring distance determination through the phase-lag method for a sample of stars, in order to refine the poorly-constrained distances of some and infer the currently unknown distances of others. We present here an update of this project.Comment: 4 pages, 1 figure, 2 tables, to appear in the Proceedings of the IAU Symposium No. 336: Astrophysical Masers: Unlocking the Mysteries of the Univers

Orbital and stochastic far-UV variability in the nova-like system V3885 Sgr

Highly time-resolved time-tagged FUSE satellite spectroscopic data are analysed to establish the far-ultraviolet (FUV) absorption line characteristics of the nova-like cataclysmic variable binary, V3885 Sgr. We determine the temporal behaviour of low (Ly_beta, CIII, NIII) and high (SIV, PV, OVI) ion species, and highlight corresponding orbital phase modulated changes in these lines. On average the absorption troughs are blueshifted due to a low velocity disc wind outflow. Very rapid (~ 5 min) fluctuations in the absorption lines are isolated, which are indicative of stochastic density changes. Doppler tomograms of the FUV lines are calculated which provide evidence for structures where a gas stream interacts with the accretion disc. We conclude that the line depth and velocity changes as a function of orbital phase are consistent with an asymmetry that has its origin in a line-emitting, localised disc-stream interaction region.Comment: Accepted for publication in MNRA