Analysis of payload bay magnetic fields due to dc power multipoint and single point ground configurations

An analysis of magnetic fields in the Orbiter Payload Bay resulting from the present grounding configuration (structure return) was presented and the amount of improvement that would result from installing wire returns for the three dc power buses was determined. Ac and dc magnetic fields at five points in a cross-section of the bay are calculated for both grounding configurations. Y and Z components of the field at each point are derived in terms of a constant coefficient and the current amplitude of each bus. The dc loads assumed are 100 Amperes for each bus. The ac noise current used is a spectrum 6 db higher than the Orbiter equipment limit for narrowband conducted emissions. It was concluded that installing return wiring to provide a single point ground for the dc Buses in the Payload Bay would reduce the ac and dc magnetic field intensity by approximately 30 db

Sail GTS ground system analysis: Avionics system engineering

A comparison of two different concepts for the guidance, navigation and control test set signal ground system is presented. The first is a concept utilizing a ground plate to which crew station, avionics racks, electrical power distribution system, master electrical common connection assembly and marshall mated elements system grounds are connected by 4/0 welding cable. An alternate approach has an aluminum sheet interconnecting the signal ground reference points between the crew station and avionics racks. The comparison analysis quantifies the differences between the two concepts in terms of dc resistance, ac resistance and inductive reactance. These parameters are figures of merit for ground system conductors in that the system with the lowest impedance is the most effective in minimizing noise voltage. Although the welding cable system is probably adequate, the aluminum sheet system provides a higher probability of a successful system design

Clusters, human capital and economic development in Oxfordshire and Cambridgeshire

Oxfordshire and Cambridgeshire are two of the most high tech economies in the UK (see for example DTI, 2002 and Garnsey and Lawton Smith, 1998). They are home to world class research universities and public and private research laboratories as well as a full range of business and professional services which support the development of their clusters. Building on previous work (Lawton Smith and Waters, 2011) this paper draws on national datasets to review the continued development of these economies. The paper considers issues such as new firm formation, sectoral composition and gross value added and relates them to social inclusion and worklessness. The paper draws on literature which emphasises the endogeneity of processes within regions, but also on studies which show that there are different kinds of high tech regions with varying industrial structures. Conclusions are drawn on the extent to which the presence of successful clusters (Spencer et al, 2010) influences outcomes for the local economy more generally, and how Oxfordshire and Cambridgeshire have performed over the last ten years

Development and initial validation of the determinants of physical activity questionnaire

Background: Physical activity interventions are more likely to be effective if they target causal determinants of behaviour change. Targeting requires accurate identification of specific theoretical determinants of physical activity. Two studies were undertaken to develop and validate the Determinants of Physical Activity Questionnaire. Methods In Study 1, 832 male and female university staff and students were recruited from 49 universities across the UK and completed the 66-item measure, which is based on the Theoretical Domains Framework. Confirmatory factor analysis was undertaken on a calibration sample to generate the model, which resulted in a loss of 31 items. A validation sample was used to cross-validate the model. 20 new items were added and Study 2 tested the revised model in a sample of 466 male and female university students together with a physical activity measure. Results: The final model consisted of 11 factors and 34 items, and CFA produced a reasonable fit χ2 (472) = 852.3, p < .001, CFI = .933, SRMR = .105, RMSEA = .042 (CI = .037-.046), as well as generally acceptable levels of discriminant validity, internal consistency, and test-retest reliability. Eight subscales significantly differentiated between high and low exercisers, indicating that those who exercise less report more barriers for physical activity. Conclusions: A theoretically underpinned measure of determinants of physical activity has been developed with reasonable reliability and validity. Further work is required to test the measure amongst a more representative sample. This study provides an innovative approach to identifying potential barriers to physical activity. This approach illustrates a method for moving from diagnosing implementation difficulties to designing and evaluating interventions

Entrepreneurship, innovation and the triple helix model: evidence from Oxfordshire and Cambridgeshire

This paper focuses on how regions become entrepreneurial and the extent to which the actors in the triple helix model are dominant at particular stages in development. It uses the case studies of Oxfordshire and Cambridgeshire in the UK to explore this theme. Both can now be described as ‘regional triple helix spaces’ (Etzkowitz 2008), and form two points of the Golden Triangle of Oxford, Cambridge and London universities. As entrepreneurial regions, however, they differ in a number of respects. This is not surprising given their differing geo-historical contexts. However, by comparing the two similar counties but which have their own distinctive features we are able to explore different dynamics which lead to the inception, implementation, consolidation and renewal (Etzkowitz and Klofsten 2005) of regions characterised by very high levels of technology-based entrepreneurship

The East Midlands in 2010

The East Midlands in 2010 is the updated evidence base that supports the regional economic strategy, A Flourishing Region. It presents a statistical portrait of the region covering demography, housing, economy & productivity, the labour market, deprivation & economic inclusion, transport, infrastructure & development, the environment and the spatial structure of the economy along with a series of sub-regional profiles

Orbiter CCTV video signal noise analysis

The amount of steady state and transient noise which will couple to orbiter CCTV video signal wiring is predicted. The primary emphasis is on the interim system, however, some predictions are made concerning the operational system wiring in the cabin area. Noise sources considered are RF fields from on board transmitters, precipitation static, induced lightning currents, and induced noise from adjacent wiring. The most significant source is noise coupled to video circuits from associated circuits in common connectors. Video signal crosstalk is the primary cause of steady state interference, and mechanically switched control functions cause the largest induced transients

Integrated Delivery Networks: In Search of Benefits and Market Effects

Integrated Delivery Networks (IDNs) have very different stated purposes than mere collections of hospitals: to coordinate care across the continuum of health services and to manage population health. IDN advocates claim that these complex enterprises yield both societal benefits and performance advantages over less integrated competitors. The purpose of this analysis is to evaluate the evidence to support these claims.For the study, researchers performed a review of the academic literature on IDN performance, as well as an analysis of publicly available quality and financial data from 15 of the biggest not-for-profit IDNs in the U.S., including Sutter Health in Northern California. The authors compared the publicly available performance information on the IDNs' flagship hospital in its principal regional market with that flagship's most significant in-market competitor. The study found that it is possible for integrated delivery networks to offer meaningful benefits, but there is little evidence they have reduced costs or improved the quality of care. Findings include:Hospital-physician integration has raised physician costs, hospital prices and per capita medical care spending;Hospital integration into health plan operations and capitated contracting was not associated either with clinical efficiency or financial efficiencyProviders are likely to see a decrease in operating margins and return on capital as they invest in IDN developmen

The Topology of Parabolic Character Varieties of Free Groups

Let G be a complex affine algebraic reductive group, and let K be a maximal compact subgroup of G. Fix elements h_1,...,h_m in K. For n greater than or equal to 0, let X (respectively, Y) be the space of equivalence classes of representations of the free group of m+n generators in G (respectively, K) such that for each i between 1 and m, the image of the i-th free generator is conjugate to h_i. These spaces are parabolic analogues of character varieties of free groups. We prove that Y is a strong deformation retraction of X. In particular, X and Y are homotopy equivalent. We also describe explicit examples relating X to relative character varieties.Comment: 16 pages, version 2 includes minor revisions and some modified proofs, accepted for publication in Geometriae Dedicat

India\u27s Healthcare Industry: A System Perspective

To western readers, analyzing a new healthcare system in the East might seem daunting. Indeed, it takes some of us decades to master an understanding of the healthcare system of our country of origin. Nevertheless, there are several methods for approaching an analysis of another country\u27s healthcare system. These include exposition of some (hopefully) invariant principles regarding healthcare that apply across contexts, analysis of what a system of health might look like, comparison with the US system (with which many are already familiar), comparison with other emerging systems such as that of China, application of existing frameworks for healthcare system analysis, appraisal of the major transitions underway in the country\u27s demographic, socioeconomic, political, and epidemiologic profile, and an analysis of the country\u27s public health issues. The chapter analyzes India\u27s healthcare system using each of these methods