A comparison of calculated and measured background noise rates in hard X-ray telescopes at balloon altitude

An actively shielded hard X-ray astronomical telescope has been flown on stratospheric balloons. An attempt is made to compare the measured spectral distribution of the background noise counting rates over the energy loss range 20-300 keV with the contributions estimated from a series of Monte Carlo and other computations. The relative contributions of individual particle interactions are assessed

Two-Rowed Hecke Algebra Representations at Roots of Unity

In this paper, we initiate a study into the explicit construction of irreducible representations of the Hecke algebra $H_n(q)$ of type $A_{n-1}$ in the non-generic case where $q$ is a root of unity. The approach is via the Specht modules of $H_n(q)$ which are irreducible in the generic case, and possess a natural basis indexed by Young tableaux. The general framework in which the irreducible non-generic $H_n(q)$-modules are to be constructed is set up and, in particular, the full set of modules corresponding to two-part partitions is described. Plentiful examples are given.Comment: LaTeX, 9 pages. Submitted for the Proceedings of the 4th International Colloquium ``Quantum Groups and Integrable Systems,'' Prague, 22-24 June 199

The City Gesture Checklist: The development of a novel gesture assessment

Background People with aphasia rely on gesture more than healthy controls to get their message across, but use a limited range of gesture types. Gesture therapy is thus a potential avenue of intervention for people with aphasia. However, currently no gesture assessment evaluates how they use gesture. Such a tool could inform therapy targets and measure outcomes. In gesture research, many different coding categories are used to describe gesture forms and functions. These coding methods are prohibitively time‐consuming to use in clinical practice. There is therefore a need for a ‘quick and dirty’ method of assessing gesture use. Aims To investigate current practice among UK‐based clinicians (speech and language therapists) in relation to gesture assessment and therapy, to synthesize gesture‐coding frameworks used in aphasia research, to develop a gesture checklist based on the synthesized coding frameworks suitable for use in clinical practice, and to investigate the interrater reliability (IRR) of the checklist among experienced and unfamiliar users. Methods & Procedures The research team synthesized seven gesture‐coding frameworks and trialled three resulting prototype checklists at a co‐design workshop with 20 clinicians. Attending clinicians were also consulted about their current clinical gesture practice using a questionnaire. A final City Gesture Checklist (CGC) was developed based upon outcomes and feedback from the workshop. The IRR of the CGC was evaluated between the research team and 11 further clinicians within a second workshop. Both groups used the CGC to count gestures in video clips of people with aphasia talking to a conversation partner. Main Contribution A total of 18 workshop attendees completed the current practice questionnaire. Of these, 10 reported assessing gesture informally and five also used formal assessment. Gesture‐coding synthesis highlighted six main categories of gesture form. Clinicians at the co‐design workshop provided feedback on prototype checklists regarding the relevance and usability of the gesture categories, layout, use of images and instructions. A final version of the CGC was created incorporating their recommendations. The IRR for the CGC was moderate between both the researchers and clinicians. Conclusions & Implications The CGC can be used to assess the types of gesture that people with aphasia produce. The IRR was moderate amongst both experienced users and new users who had received no training. Future research directions include investigating how to improve IRR, evaluating intra‐rater reliability and sensitivity to change, and exploring use of the CGC in clinical practice

Implementing AAC with children with profound and multiple learning disabilities: a study in rationale underpinning intervention

There is a developing research base to support the rationale underpinning augmentative and alternative communication (AAC) for people with learning disabilities. However, there is a paucity of research examining the process involved in implementing AAC support for people who have profound disabilities. This paper seeks to explore the processes involved in planning and implementing AAC systems to support the communication of two six year olds with profound and multiple learning disabilities. Following assessment, a plan of intervention involving specific implementation of objects of reference, gestures and signs was implemented to enhance communication opportunities for both children. Both children improved their communication skills through use of specific AAC supports. Results suggest that important aspects to include when planning intervention are understanding the level of each child’s cognition in relation to their receptive abilities, and a consistent, collaborative approach where strategies are agreed between team members. Specific challenges are discussed

On the idempotents of Hecke algebras

We give a new construction of primitive idempotents of the Hecke algebras associated with the symmetric groups. The idempotents are found as evaluated products of certain rational functions thus providing a new version of the fusion procedure for the Hecke algebras. We show that the normalization factors which occur in the procedure are related to the Ocneanu--Markov trace of the idempotents.Comment: 11 page

Pulmonary tuberculosis in a South African regional emergency centre: Can infection control be improved to lower the risk of nosocomial transmission?

Background. George Regional Hospital (GRH) is a 272-bed regional referral hospital for the Eden and Central Karoo districts, Western Cape Province, South Africa. The perception among emergency centre (EC) staff is that a high burden of tuberculosis (TB) is being diagnosed and that infection control procedures are currently lacking, leading to a high risk of nosocomial transmission.Objectives. To establish the burden of pulmonary TB (PTB) presenting to GRH via the EC and audit current infection prevention and control practices, to quantify the risk of transmission of PTB in the EC and to establish whether infection control measures are inadequate.Methods. An audit of infection control based on the Centers for Disease Control audit tool for TB, analysis of results, and implementation of new infection control measures including a new standard operating procedure based on a set of triage criteria.Results. Implementation of new triage criteria and a standard operating procedure led to the longest length of stay of a patient with suspected TB in the EC being reduced by 40% (from 142 hours to 84 hours). The average time between seeing a doctor and leaving the EC for patients with suspected TB was reduced by 20% (from 20 hours 40 minutes to 16 hours 45 minutes).Conclusion. Simple measures implemented in the EC led to a significant reduction in the time patients with suspected or confirmed TB spent in the EC. This should lead to a reduced risk of nosocomial transmission of TB to both staff and patients

Suitability of GPUs for real-time control of large astronomical adaptive optics instruments

Adaptive optics (AO) is a technique for correcting aberrations introduced when light propagates through a medium, for example, the light from stars propagating through the turbulent atmosphere. The components of an AO instrument are: (1) a camera to record the aberrations, (2) a corrective mechanism to correct them, (3) a real-time controller (RTC) that processes the camera images and steers the corrective mechanism on milliseconds timescales. We have accelerated the image processing for the AO RTC with the use of graphics processing units (GPUs). It is crucial that the image is processed before the atmospheric turbulence has changed, i.e., in one or two milliseconds. The main task is to transfer the images to the GPU memory with a minimum delay. The key result of this paper is a demonstration that this can be done fast enough using commercial frame grabbers and standard CUDA tools. Our benchmarking image consists of 1.6×1061.6×106 pixels out of which 1.2×1061.2×106 are used in processing. The images are characterized and reduced into a set of 9248 numbers; about one-third of the total processing time is spent on this characterization. This set of numbers is then used to calculate the commands for the corrective system, which takes about two-third of the total time. The processing rate achieved on a single GPU is about 700 frames per second (fps). This increases to 1100 fps (1565 fps) if we use two (four) GPUs. The variation in processing time (jitter) has a root-mean-square value of 20–30 μμ s and about one outlier in a million cycles

Homomorphisms and Higher Extensions for Schur algebras and symmetric groups

This paper surveys, and in some cases generalises, many of the recent results on homomorphisms and the higher Ext groups for q-Schur algebras and for the Hecke algebra of type A. We review various results giving isomorphisms between Ext groups in the two categories, and discuss those cases where explicit results have been determined

The 4U 0115+63: Another energetic gamma ray binary pulsar

Following the discovery of Her X-1 as a source of pulsed 1000 Gev X-rays, a search for emission from an X-ray binary containing a pulsar with similar values of period, period derivative and luminosity was successful. The sporadic X-ray binary 4U 0115-63 has been observed, with probability 2.5 x 10 to the minus 6 power ergs/s to emit 1000 GeV gamma-rays with a time averaged energy flux of 6 to 10 to the 35th power