Long-term stability of fibre-optic transmission for multi-object spectroscopy

We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from six years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope is presented. We find no evidence for significant degradation in the bulk transmission properties of the 38 m optical fibre train. Significant losses (<20% relative, 4% absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation.Comment: Accepted for publication (September 2012) Monthly Notices of the Royal Astronomical Societ

Can shared surfaces be safely negotiated by blind and partially sighted people?

‘Shared Space’ schemes are designed to remove the physical distinction between pedestrian space and traffic space in the street environment to encourage more pedestrians to use the area. They may also make it easier for people with wheelchairs, prams or similar to negotiate the space. However, by removing the kerbs, blind and partially sighted people lose one of the key references that they normally use to know they are in a safe space away from vehicles and to navigate around the area. This study is intended to understand what people with visual impairments need from a surface to make it clearly detectable, given that it should not be a barrier to progress for people with other mobility limitations. With this information, some surfaces were tested to determine their suitability as a delineator. Approach and/or Methodology An experimental approach was adopted. People with mobility impairments and blind and partially sighted people were recruited. All participants used the normal street environment unaccompanied. The blind and partially sighted participants included people who use a guide dog, those who use a long cane and those who use no assistive device. The people with mobility impairments all used some form of mobility aid for example walking stick or wheelchair. The tests were run in the pedestrian testing facility PAMELA at UCL. The top surface of the test facility was predominantly concrete paving slab, but with test surfaces discretely located. The task for all participants was to travel from one designated place in the test area to another. For some of these trials the participant would encounter one of the test surfaces, but on other trials they would not. After each trial the participants were asked to rate how easy it was to detect a change in surface, or how easy it was to pass over the surface. The different surfaces included blister paving, corduroy paving, a central delineator, slopes, roughened surfaces, and traditional kerb upstands of different heights. Results or Expected Results None of the 400mm wide surfaces was detected by all participants. Changes in level through slopes were considered both positively and negatively, some people asking for steeper gradients and some less steep. Kerb heights below 60mm were not reliably detectable by blind or partially sighted people and are an obstacle to people in wheelchairs. Further tests on more surfaces are in process and the results will be incorporated into this paper. Conclusion Early suggestions for detectable surfaces – proposed in UK schemes - have been either a barrier to people with mobility impairments, or difficult to detect for blind and partially sighted people or both. The work presented in this paper shows the difficulty in finding a suitable dual purpose surface, yet clarifies the design requirements for shared space delineators for people with mobility impairments and blind or partially sighted people. This work has reinforced the point that 400mm width is insufficient to be used as a tactile surface. Further conclusions will be made after the additional surface tests. Topic Code: Ca C. Accessibility concerns and solutions for those with cognitive and sensory impairment a. Pedestrian safety at crossings and intersection

Subglacial drainage processes at a High Arctic polythermal valley glacier

Peer reviewedPublisher PD

A new fabrication method for precision antenna reflectors for space flight and ground test

Communications satellites are using increasingly higher frequencies that require increasingly precise antenna reflectors for use in space. Traditional industry fabrication methods for space antenna reflectors employ successive modeling techniques using high- and low-temperature molds for reflector face sheets and then a final fit-up of the completed honeycomb sandwich panel antenna reflector to a master pattern. However, as new missions are planned at much higher frequencies, greater accuracies will be necessary than are achievable using these present methods. A new approach for the fabrication of ground-test solid-surface antenna reflectors is to build a rigid support structure with an easy-to-machine surface. This surface is subsequently machined to the desired reflector contour and coated with a radio-frequency-reflective surface. This method was used to fabricate a 2.7-m-diameter ground-test antenna reflector to an accuracy of better than 0.013 mm (0.0005 in.) rms. A similar reflector for use on spacecraft would be constructed in a similar manner but with space-qualified materials. The design, analysis, and fabrication of the 2.7-m-diameter precision antenna reflector for antenna ground tests and the extension of this technology to precision, space-based antenna reflectors are described

Transgenic Overexpression of LARGE Induces alpha-Dystroglycan Hyperglycosylation in Skeletal and Cardiac Muscle

Background: LARGE is one of seven putative or demonstrated glycosyltransferase enzymes defective in a common group of muscular dystrophies with reduced glycosylation of alpha-dystroglycan. Overexpression of LARGE induces hyperglycosylation of alpha-dystroglycan in both wild type and in cells from dystroglycanopathy patients, irrespective of their primary gene defect, restoring functional glycosylation. Viral delivery of LARGE to skeletal muscle in animal models of dystroglycanopathy has identical effects in vivo, suggesting that the restoration of functional glycosylation could have therapeutic applications in these disorders. Pharmacological strategies to upregulate Large expression are also being explored.Methodology/Principal Findings: In order to asses the safety and efficacy of long term LARGE over-expression in vivo, we have generated four mouse lines expressing a human LARGE transgene. On observation, LARGE transgenic mice were indistinguishable from the wild type littermates. Tissue analysis from young mice of all four lines showed a variable pattern of transgene expression: highest in skeletal and cardiac muscles, and lower in brain, kidney and liver. Transgene expression in striated muscles correlated with alpha-dystroglycan hyperglycosylation, as determined by immunoreactivity to antibody IIH6 and increased laminin binding on an overlay assay. Other components of the dystroglycan complex and extracellular matrix ligands were normally expressed, and general muscle histology was indistinguishable from wild type controls. Further detailed muscle physiological analysis demonstrated a loss of force in response to eccentric exercise in the older, but not in the younger mice, suggesting this deficit developed over time. However this remained a subclinical feature as no pathology was observed in older mice in any muscles including the diaphragm, which is sensitive to mechanical load-induced damage.Conclusions/Significance: This work shows that potential therapies in the dystroglycanopathies based on LARGE upregulation and alpha-dystroglycan hyperglycosylation in muscle should be safe

Self-Consistent Determination of Coupling Shifts in Broken SU(3)

The possibility that certain patterns of SU(3) symmetry breaking are dynamically enhanced in baryon-meson couplings is studied by bootstrap methods. For the strong couplings, a single dominant enhancement is found. It produces very large symmetry-breaking terms, transforming like an octet, as often conjectured. Experimental consequences are listed, such as a reduction of K-baryon couplings relative to π-baryon couplings which is in accord with the experimental weakness of K relative to π production in many circumstances, such as photoproduction and multi-BeV cosmic-ray collisions. For parity-violating nonleptonic couplings, a dominant octet enhancement is again found, as mentioned in a previous paper, which leads to an excellent fit with experiment. For parity-conserving nonleptonic couplings, on the other hand, several different enhancements compete, and the only conclusion we can draw is that terms with the "abnormal" transformation properties brought in by strong symmetry-breaking corrections are present. Our work provides a dynamical derivation of various phenomenological facts associated with SU(6), such as the dominance of the 35 representation in parity-violating nonleptonic decays

Spacelab 3 flight experiment No. 3AFT23: Autogenic-feedback training as a preventive method for space adaptation syndrome

Space adaptation syndrome is a motion sickness-like disorder which affects up to 50 percent of all people exposed to microgravity in space. This experiment tested a physiological conditioning procedure (Autogenic-Feedback Training, AFT) as an alternative to pharmacological management. Four astronauts participated as subjects in this experiment. Crewmembers A and B served as treatment subjects. Both received preflight training for control of heart rate, respiration rate, peripheral blood volume, and skin conductance. Crewmembers C and D served as controls (i.e., did not receive training). Crewmember A showed reliable control of his own physiological responses, and a significant increase in motion sickness tolerance after training. Crewmember B, however, demonstrated much less control and only a moderate increase in motion sickness tolerance was observed after training. The inflight symptom reports and physiological data recordings revealed that Crewmember A did not experience any severe symptom episodes during the mission, while Crewmember B reported one severe symptom episode. Both control group subjects, C and D (who took antimotion sickness medication), reported multiple symptom episodes on mission day 0. Both inflight data and crew reports indicate that AFT may be an effective countermeasure. Additional data must be obtained inflight (a total of eight treatment and eight control subjects) before final evaluation of this treatment can be made

Unsung heroes: who supports social work students on placement?

Since the introduction of the three year degree programme in 2003, social work education has undergone a number of significant changes. The time students spend on placement has been increased to two hundred days, and the range of placement opportunities and the way in which these placements have been configured has significantly diversified. A consistent feature over the years, however, has been the presence of a Practice Educator (PE) who has guided, assessed and taught the student whilst on placement. Unsurprisingly, the role of the PE and the pivotal relationship they have with the student has been explored in the past and features in social work literature. This paper, however, concentrates on a range of other relationships which are of significance in providing support to students on placement. In particular it draws on research to discuss the role of the university contact tutor, the place of the wider team in which the student is sited, and the support offered by family, friends and others. Placements and the work undertaken by PE’s will continue to be integral to the delivery of social work education. It is, however, essential to recognise and value the often over looked role of others in providing support to students on placement

A mechanical, thermal and electrical packaging design for a prototype power management and control system for the 30 cm mercury ion thruster

A prototype electric power management and thruster control system for a 30 cm ion thruster is described. The system meets all of the requirements necessary to operate a thruster in a fully automatic mode. Power input to the system can vary over a full two to one dynamic range (200 to 400 V) for the solar array or other power source. The power management and control system is designed to protect the thruster, the flight system and itself from arcs and is fully compatible with standard spacecraft electronics. The system is easily integrated into flight systems which can operate over a thermal environment ranging from 0.3 to 5 AU. The complete power management and control system measures 45.7 cm (18 in.) x 15.2 cm (6 in.) x 114.8 cm (45.2 in.) and weighs 36.2 kg (79.7 lb). At full power the overall efficiency of the system is estimated to be 87.4 percent. Three systems are currently being built and a full schedule of environmental and electrical testing is planned

Co-crystalization and in vitro biological characterization of 5-Aryl-4-(5-substituted-2-4-dihydroxyphenyl)-1,2,3-thiadiazole Hsp90 inhibitors

A potential therapeutic strategy for targeting cancer that has gained much interest is the inhibition of the ATP binding and ATPase activity of the molecular chaperone Hsp90. We have determined the structure of the human Hsp90α N-terminal domain in complex with a series of 5-aryl-4-(5-substituted-2-4-dihydroxyphenyl)-1,2,3-thiadiazoles. The structures provide the molecular details for the activity of these inhibitors. One of these inhibitors, ICPD 34, causes a structural change that affects a mobile loop, which adopts a conformation similar to that seen in complexes with ADP, rather than the conformation generally seen with the pyrazole/isoxazole-resorcinol class of inhibitors. Competitive binding to the Hsp90 N-terminal domain was observed in a biochemical assay, and these compounds showed antiproliferative activity and induced apoptosis in the HCT116 human colon cancer cell line. These inhibitors also caused induction of the heat shock response with the upregulation of Hsp72 and Hsp27 protein expression and the depletion of Hsp90 clients, CRAF, ERBB2 and CDK4, thus confirming that antiproliferative activity was through the inhibition of Hsp90. The presence of increased levels of the cleavage product of PARP indicated apoptosis in response to Hsp90 inhibitors. This work provides a framework for the further optimization of thiadiazole inhibitors of Hsp90. Importantly, we demonstrate that the thiadiazole inhibitors display a more limited core set of interactions relative to the clinical trial candidate NVP-AUY922, and consequently may be less susceptible to resistance derived through mutations in Hsp9