Control strategies for integration of electric motor assist and functional electrical stimulation in paraplegic cycling: Utility for exercise testing and mobile cycling

AIM: The aim of this study was to investigate feedback control strategies for integration of electric motor assist and functional electrical stimulation (FES) for paraplegic cycling, with particular focus on development of a testbed for exercise testing in FES cycling, in which both cycling cadence and workrate are simultaneously well controlled and contemporary physiological measures of exercise performance derived. A second aim was to investigate the possible benefits of the approach for mobile, recreational cycling. METHODS: A recumbent tricycle with an auxiliary electric motor is used, which is adapted for paraplegic users, and instrumented for stimulation control. We propose a novel integrated control strategy which simultaneously provides feedback control of leg power output (via automatic adjustment of stimulation intensity) and cycling cadence (via electric motor control). Both loops are designed using system identification and analytical (model-based) feedback design methods. Ventilatory and pulmonary gas exchange response profiles are derived using a portable system for real-time breath-by-breath acquisition. RESULTS:We provide indicative results from one paraplegic subject in which a series of feedback-control tests illustrate accurate control of cycling cadence, leg power control, and external disturbance rejection. We also provide physiological response profiles from a submaximal exercise step test and a maximal incremental exercise test, as facilitated by the control strategy. CONCLUSION: The integrated control strategy is effective in facilitating exercise testing under conditions of well-controlled cadence and power output. Our control approach significantly extends the achievable workrate range and enhances exercise-test sensitivity for FES cycling, thus allowing a more stringent characterization of physiological response profiles and estimation of key parameters of aerobic function.We further conclude that the control approach can significantly improve the overall performance of mobile recreational cycling

Crow Deaths Caused by West Nile Virus during Winter

In New York, an epizootic of American crow (Corvus brachyrhynchos) deaths from West Nile virus (WNV) infection occurred during winter 2004–2005, a cold season when mosquitoes are not active. Detection of WNV in feces collected at the roost suggests lateral transmission through contact or fecal contamination

Development of control systems for space shuttle vehicles, volume 1

Control of winged two-stage space shuttle vehicles was investigated. Control requirements were determined and systems capable of meeting these requirements were synthesized. Control requirements unique to shuttles were identified. It is shown that these requirements can be satisfied by conventional control logics. Linear gain schedule controllers predominate. Actuator saturations require nonlinear compensation in some of the control systems

Galactic Cosmic Ray Origins and OB Associations: Evidence from SuperTIGER Observations of Elements 26_{26}Fe through 40_{40}Zr

We report abundances of elements from $_{26}$Fe to $_{40}$Zr in the cosmic radiation measured by the SuperTIGER (Trans-Iron Galactic Element Recorder) instrument during 55 days of exposure on a long-duration balloon flight over Antarctica. These observations resolve elemental abundances in this charge range with single-element resolution and good statistics. These results support a model of cosmic-ray origin in which the source material consists of a mixture of 19$^{+11}_{-6}$\% material from massive stars and $\sim$81\% normal interstellar medium (ISM) material with solar system abundances. The results also show a preferential acceleration of refractory elements (found in interstellar dust grains) by a factor of $\sim$4 over volatile elements (found in interstellar gas) ordered by atomic mass (A). Both the refractory and volatile elements show a mass-dependent enhancement with similar slopes.Comment: 9 pages, 12 figures, 2 tables, accepted by Ap

Type III migration in a low viscosity disc

We study the type III migration of a Saturn mass planet in low viscosity discs. The planet is found to experience cyclic episodes of rapid decay in orbital radius, each amounting to a few Hill radii. We find this to be due to the scattering of large- scale vortices present in the disc. The origin and role of vortices in the context of type III migration is explored. It is shown through numerical simulations and semi- analytical modelling that spiral shocks induced by a sufficiently massive planet will extend close to the planet orbital radius. The production of vortensity across shock tips results in thin high vortensity rings with a characteristic width of the local scale height. For planets with masses equal to and above that of Saturn, the rings are co-orbital features extending the entire azimuth. Linear stability analysis show there exists unstable modes that are localised about local vortensity minima which coincide with gap edges. Simulations show that vortices are non-linear a outcome. We used hydrodynamic simulations to examine vortex-planet interactions. Their effect is present in discs with kinematic viscosity less than about an order of magnitude smaller than the typically adopted value of \nu = 10^{-5}\Omega_pr_p(0)^2, where r_p(0) and \Omega_p are the initial orbital radius and angular velocity of the planet respectively. We find that the magnitude of viscosity affects the nature of type III migration but not the extent of the orbital decay. The role of vortices as a function of initial disc mass is also explored and it is found that the amount of orbital decay during one episode of vortex-planet interaction is independent of initial disc mass. We incorporate the concept of the co-orbital mass deficit in the analysis of our results and link it to the presence of vortices at gap edges.Comment: 20 pages, 20 figures, accepted for publication in MNRA

VecTest as Diagnostic and Surveillance Tool for West Nile Virus in Dead Birds

The VecTest WNV assay is adequate for diagnostic and surveillance purposes in American Crows, Blue Jays, and House Sparrows

Lobular carcinoma in situ of the breast is not caused by constitutional mutations in the E-cadherin gene

Lobular carcinoma in situ (LCIS) is an unusual histological pattern of non-invasive neoplastic disease of the breast occurring predominantly in women aged between 40 and 50 years. LCIS is frequently multicentric and bilateral, and there is evidence that it is associated with an elevated familial risk of breast cancer. Although women with LCIS suffer an increased risk of invasive breast disease, this risk is moderate suggesting that LCIS may result from mutation of a gene or genes conferring a high risk of LCIS, but a lower risk of invasive breast cancer. The high frequency of somatic mutations in E-cadherin in LCIS, coupled with recent reports that germline mutations in this gene can predispose to diffuse gastric cancer, raised the possibility that constitutional E-cadherin mutations may confer susceptibility to LCIS. In order to explore this possibility we have examined a series of 65 LCIS patients for germline E-cadherin mutations. Four polymorphisms were detected but no pathogenic mutations were identified. The results indicate that E-cadherin is unlikely to act as a susceptibility gene for LCIS. © 2000 Cancer Research Campaig

Characterization of acousto-optical interaction in planar silica optical waveguide by the finite element method

A full-vectorial finite element based approach is used to find accurate modal solutions for the acoustic modes in a Ge-doped planar silica optical waveguide. To enhance the accuracy of the solution, the existing structural symmetry is exploited and rigorous analyses of the interactions between the guided acoustic and optical modes are performed. The Stimulated Brillouin Scattering (SBS) frequency and the overlaps between the fundamental and the higher order transverse and longitudinal acoustic modes and the fundamental quasi-TE optical mode are presented

Atomic-scale representation and statistical learning of tensorial properties

This chapter discusses the importance of incorporating three-dimensional symmetries in the context of statistical learning models geared towards the interpolation of the tensorial properties of atomic-scale structures. We focus on Gaussian process regression, and in particular on the construction of structural representations, and the associated kernel functions, that are endowed with the geometric covariance properties compatible with those of the learning targets. We summarize the general formulation of such a symmetry-adapted Gaussian process regression model, and how it can be implemented based on a scheme that generalizes the popular smooth overlap of atomic positions representation. We give examples of the performance of this framework when learning the polarizability and the ground-state electron density of a molecule

Following the signs: applying urban regime analysis to a UK case study

As the debate continues regarding the applicability of urban regime analysis in a UK context, three aspects stand out as highly significant: the target for analysis, the mode of scrutiny, and the context of local governing arrangements with its implications for interdependence as an impetus for co-operation. This article will examine urban regime analysis and the move from government to governance in order to answer why and how the private, voluntary and public sectors might be inclined to collaborate in regimes. In addition, the regime analysis will provide the parameters for examination whilst the issue of governance will afford context for local governing arrangements. Although some issues require slight reframing to reflect the UK context, the article will follow a rigorous framework for examination utilizing the full weight of regime analysis as articulated by Stone such that it could not be accused of “concept stretching.” Far from it: Through the examination of an informal partnership, a coalition of actors from the public, private, and voluntary sectors that has been in existence for more than 13 years, the article focuses, specifically, on the long-term, less visible aspects of local governance. As such, it is able to demonstrate how economic and political change can have a tangible effect on the manifestation of interdependence as an impetus for co-operation, not only for this specific locale but also for other cities facing similar challenges