1,444 research outputs found
Obstetrics and Gynecology at the University of Iowa: Three leaders and 51 years
In his history of the Department of Obstetrics and Gynecology of the University of Iowa College of Medicine, William C. Keettel traced the evolution of the department from its origin in 1870 until 1980. This article will focus on a particular segment of the departmentâs history, that from 1926 to 1977, in which the department grew and developed to a position of national stature. During this 51-year period, departmental leadership was provided by three individuals, E. D. Plass (1926-1951), John H. Randall (1952-1959), and William C. Keettel (1959-1977) and this paper will consider these three men and their contributions to the departmentâs growth and development. The 1980 department history provided most of the basis of the article, although a small amount of the Randall section and a substantial amount of the Keettel section reflect my personal perspective and recollections
Advanced technologies for future ground-based, laser-interferometric gravitational wave detectors
We present a review of modern optical techniques being used and developed for the field of gravitational wave detection. We describe the current state-of-the-art of gravitational waves detector technologies with regard to optical layouts, suspensions and test masses. We discuss the dominant sources and noise in each of these subsystems and the developments that will help mitigate them for future generations of detectors. We very briefly summarise some of the novel astrophysics that will be possible with these upgraded detectors
Dynamic input to determine hip joint moments, power and work on the prosthetic limb of transfemoral amputees: ground reactions vs knee reactions
Study Design: Comparative analysis\ud
Background: Calculations of lower limbs kinetics are limited by floor-mounted force-plates.\ud
Objectives: Comparison of hip joint moments, power and mechanical work on the prosthetic limb of a transfemoral amputee calculated by inverse dynamics using either the ground reactions (force-plates) or knee reactions (transducer).\ud
Methods: Kinematics, ground reactions and knee reactions were collected using a motion analysis system, two force-plates and a multi-axial transducer mounted below the socket, respectively.\ud
Results: The inverse dynamics using ground reactions under-estimated the peaks of hip energy generation and absorption occurring at 63 % and 76 % of the gait cycle (GC) by 28 % and 54 %, respectively. This method over-estimated a phase of negative work at the hip (from 37 %GC to 56 %GC) by 24%. It under-estimated the phases of positive (from 57 %GC to 72 %GC) and negative (from 73 %GC to 98 %GC) work at the hip by 11 % and 58%, respectively.\ud
Conclusions: A transducer mounted within the prosthesis has the capacity to provide more realistic kinetics of the prosthetic limb because it enables assessment of multiple consecutive steps and a wide range of activities without issues of foot placement on force-plates
The declining representativeness of the British party system, and why it matters
In a recent article, Michael Laver has explained âWhy Vote-Seeking Parties May Make Voters Miserableâ. His model shows that, while ideological convergence may boost congruence between governments and the median voter, it can reduce congruence between the party system and the electorate as a whole. Specifically, convergence can increase the mean distance between voters and their nearest party. In this article we show that this captures the reality of todayâs British party system. Policy scale placements in British Election Studies from 1987 to 2010 confirm that the pronounced convergence during the past decade has left the Conservatives and Labour closer together than would be optimal in terms of minimising the policy distance between the average voter and the nearest major party. We go on to demonstrate that this comes at a cost. Respondents who perceive themselves as further away from one of the major parties in the system tend to score lower on satisfaction with democracy. In short, vote-seeking parties have left the British party system less representative of the ideological diversity in the electorate, and thus made at least some British voters miserable
Report on the first round of the Mock LISA Data Challenges
The Mock LISA Data Challenges (MLDCs) have the dual purpose of fostering the
development of LISA data analysis tools and capabilities, and demonstrating the
technical readiness already achieved by the gravitational-wave community in
distilling a rich science payoff from the LISA data output. The first round of
MLDCs has just been completed: nine data sets containing simulated
gravitational wave signals produced either by galactic binaries or massive
black hole binaries embedded in simulated LISA instrumental noise were released
in June 2006 with deadline for submission of results at the beginning of
December 2006. Ten groups have participated in this first round of challenges.
Here we describe the challenges, summarise the results, and provide a first
critical assessment of the entries.Comment: Proceedings report from GWDAW 11. Added author, added reference,
clarified some text, removed typos. Results unchanged; Removed author, minor
edits, reflects submitted versio
The Sensitivity of the Parkes Pulsar Timing Array to Individual Sources of Gravitational Waves
We present the sensitivity of the Parkes Pulsar Timing Array to gravitational
waves emitted by individual super-massive black-hole binary systems in the
early phases of coalescing at the cores of merged galaxies. Our analysis
includes a detailed study of the effects of fitting a pulsar timing model to
non-white timing residuals. Pulsar timing is sensitive at nanoHertz frequencies
and hence complementary to LIGO and LISA. We place a sky-averaged constraint on
the merger rate of nearby () black-hole binaries in the early phases
of coalescence with a chirp mass of 10^{10}\,\rmn{M}_\odot of less than one
merger every seven years. The prospects for future gravitational-wave astronomy
of this type with the proposed Square Kilometre Array telescope are discussed.Comment: fixed error in equation (4). [13 pages, 6 figures, 1 table, published
in MNRAS
Status of the GEO600 gravitational wave detector
The GEO600 laser interferometric gravitational wave detector is approaching the end of its commissioning phase which started in 1995.During a test run in January 2002 the detector was operated for 15 days in a power-recycled michelson configuration. The detector and environmental data which were acquired during this test run were used to test the data analysis code. This paper describes the subsystems of GEO600, the status of the detector by August 2002 and the plans towards the first science run
Gravitational wave detection using pulsars: status of the Parkes Pulsar Timing Array project
The first direct detection of gravitational waves may be made through
observations of pulsars. The principal aim of pulsar timing array projects
being carried out worldwide is to detect ultra-low frequency gravitational
waves (f ~ 10^-9 to 10^-8 Hz). Such waves are expected to be caused by
coalescing supermassive binary black holes in the cores of merged galaxies. It
is also possible that a detectable signal could have been produced in the
inflationary era or by cosmic strings. In this paper we review the current
status of the Parkes Pulsar Timing Array project (the only such project in the
Southern hemisphere) and compare the pulsar timing technique with other forms
of gravitational-wave detection such as ground- and space-based interferometer
systems.Comment: Accepted for publication in PAS
What do descriptive representatives describe? Minority representative claims and the limits of Shape-shifting
In contemporary debates on diversity, minorities are characterized mostly in terms of their cultural difference from the majority. Scholars have tended to focus on the role of minority representatives as advocates of their group interests in legislative assemblies. Focussing on election campaigns, this article examines how minority representatives reach out to a mixed electorate, comprising voters of both minority and non-minority backgrounds. Bringing together two distinct strands of the recent representative turn in political theory, theories of descriptive representation and constructivist theories of representation, I argue the following. First the influential contrast between the politics of presence and the politics of ideas underestimates the multi-dimensional and dynamic nature of minority identities as well as the respects in which minority representation is conditioned and constrained by the politics of ideas associated with party competition. Second, while Sawardâs notion of shape-shifting representation is promising for illuminating the multiple positionalities of minority representatives and the dynamic character of descriptive representation, its current formulation does not offer adequate criteria for operationalizing shape-shifting and evaluating its democratic character. Third, ethnographic approaches have an important role to play in countering the tendency in normative debates for the reification of minority identities and the idealization of the democratic role of political parties. These arguments are established through a comparative case study of the representative claims of BJP MPs of Dalit (Scheduled Caste) and Muslim backgrounds during the 2014 Indian national election campaign
Actors of the common interest? The Brussels offices of the regions.
The absence of a formal place in representative democracy at EU level casts sub-national authorities more as actors of EU participatory democracy. Where they have specific interests to pursue their Brussels offices act in the same way as lobbyists, but public authorities are also capable of acting on broader interest sets. This analysis is geared to understanding variation in the extent to which the diversely constituted Brussels offices of the regions can act on a broad spectrum of civil society interests, and thus have potential as actors of European integration in connecting civil society with EU institutions. Differences in the orientation of offices towards either highly defined or broad agendas can be conceived in qualified principal-agent terms, in which the autonomy of offices to develop activities is the critical explanatory factor. This autonomy can be derived more from the structure of principals and from degrees of purpose they have than from asymmetries of power between principals and agents, which in turn can be drawn from typologies of degrees of devolved authority present in different member states. It predicts that territorial offices from member states with medium degrees of devolved authority have the greatest potential to act on a broad range of civil society oriented interests
- âŠ