1,806 research outputs found
HIP CIRCLE TO HANDSTAND ON THE UNEVEN PARALLEL BARS
Public interest in women's gymnastics has increased over the past two decades as a result of the publicity accorded such performers as Cathy Rigby, Olga Korbut, and Nadia Comenici. Many researchers and gymnastics coaches have sought to explain gymnastics skills through the use of scientific techniques, but because of the dearth of quantitative information available about women's gymnastics, the coach and performer have had to rely on subjective information which has been disseminated from past performers and coaches (Cureton & Welser, 1970). Because there is a lack of scientific information available, gymnastics coaches and performers have tended to adopt the methods and techniques of the current champions, often disregarding correct technique (Wilkerson, 1978). It is the hope of the investigator that the findings of this study may be beneficial to future studies of gymnastics related skills , and may also contribute to the improvement of teaching and coaching the skills performed on the uneven parallel bars
BODY COMPOSITION AND HIP FLEXIBILITY OF SYNCHRONIZED SWIMMERS
Public interest in synchronized swimming has increased as a result of the 1984 Summer Olympics, however, there has been very little research completed to date on this sport. The information presented in this paper is the result of the first year of a five year longitudinal study to determine body composition and hip flexibility characteristics of intermediate and elite synchronized swimmers
A prospective cohort study assessing clinical referral management & workforce allocation within a UK regional medical genetics service
Abstract
Ensuring patient access to genomic information in the face of increasing demand requires clinicians to develop innovative ways of working. This paper presents the first empirical prospective observational cohort study of UK multi-disciplinary genetic service delivery. It describes and explores collaborative working practices including the utilisation and role of clinical geneticists and non-medical genetic counsellors. Six hundred and fifty new patients referred to a regional genetics service were tracked through 850 clinical contacts until discharge. Referral decisions regarding allocation of lead health professional assigned to the case were monitored, including the use of initial clinical contact guidelines. Significant differences were found in the cases led by genetic counsellors and those led by clinical geneticists. Around a sixth, 16.8% (109/650) of referrals were dealt with by a letter back to the referrer or re-directed to another service provider and 14.8% (80/541) of the remaining patients chose not to schedule an appointment. Of the remaining 461 patients, genetic counsellors were allocated as lead health professional for 46.2% (213/461). A further 61 patients did not attend. Of those who did, 86% (345/400) were discharged after one or two appointments. Genetic counsellors contributed to 95% (784/825) of total patient contacts. They provided 93.7% (395/432) of initial contacts and 26.8% (106/395) of patients were discharged at that point. The information from this study informed a planned service re-design. More research is needed to assess the effectiveness and efficiency of different models of collaborative multi-disciplinary working within genetics services. Keywords (MeSH terms)
Genetic Services, Genetic Counseling, Interdisciplinary Communication, Cohort Studies, Delivery of Healthcare, Referral and Consultation
Mucosal Priming of Simian Immunodeficiency Virus-Specific Cytotoxic T-Lymphocyte Responses in Rhesus Macaques by the \u3ci\u3eSalmonella\u3c/i\u3e Type III Secretion Antigen Delivery System
Nearly all human immunodeficiency virus (HIV) infections are acquired mucosally, and the gut-associated lymphoid tissues are important sites for early virus replication. Thus, vaccine strategies designed to prime virus-specific cytotoxic T lymphocyte (CTL) responses that home to mucosal compartments may be particularly effective at preventing or containing HIV infection. The Salmonella type III secretion system has been shown to be an effective approach for stimulating mucosal CTL responses in mice. We therefore tested âphoP-phoQ attenuated strains of Salmonella enterica serovar Typhimurium and S. enterica serovar Typhi expressing fragments of the simian immunodeficiency virus (SIV) Gag protein fused to the type III-secreted SopE protein for the ability to prime virus-specific CTL responses in rhesus macaques. Mamu-A*01+ macaques were inoculated with three oral doses of recombinant Salmonella, followed by a peripheral boost with modified vaccinia virus Ankara expressing SIV Gag (MVA Gag). Transient low-level CTL responses to the Mamu-A*01 Gag181-189 epitope were detected following each dose of Salmonella. After boosting with MVA Gag, strong Gag-specific CTL responses were consistently detected, and tetramer staining revealed the expansion of Gag181-189-specific CD8+ T-cell responses in peripheral blood. A significant percentage of the Gag181-189- specific T-cell population in each animal also expressed the intestinal homing receptor α4ÎČ7. Additionally, Gag181-189-specific CD8+ T cells were detected in lymphocytes isolated from the colon. Yet, despite these responses, Salmonella-primed/MVA-boosted animals did not exhibit improved control of virus replication following a rectal challenge with SIVmac239. Nevertheless, this study demonstrates the potential of mucosal priming by the Salmonella type III secretion system to direct SIV-specific cellular immune responses to the gastrointestinal mucosa in a primate model
A close halo of large transparent grains around extreme red giant stars
Intermediate-mass stars end their lives by ejecting the bulk of their
envelope via a slow dense wind back into the interstellar medium, to form the
next generation of stars and planets. Stellar pulsations are thought to elevate
gas to an altitude cool enough for the condensation of dust, which is then
accelerated by radiation pressure from starlight, entraining the gas and
driving the wind. However accounting for the mass loss has been a problem due
to the difficulty in observing tenuous gas and dust tens of milliarcseconds
from the star, and there is accordingly no consensus on the way sufficient
momentum is transferred from the starlight to the outflow. Here, we present
spatially-resolved, multi-wavelength observations of circumstellar dust shells
of three stars on the asymptotic giant branch of the HR diagram. When imaged in
scattered light, dust shells were found at remarkably small radii (<~ 2 stellar
radii) and with unexpectedly large grains (~300 nm radius). This proximity to
the photosphere argues for dust species that are transparent to starlight and
therefore resistant to sublimation by the intense radiation field. While
transparency usually implies insufficient radiative pressure to drive a wind,
the radiation field can accelerate these large grains via photon scattering
rather than absorption - a plausible mass-loss mechanism for lower-amplitude
pulsating stars.Comment: 13 pages, 1 table, 6 figure
Obscuration of Supersoft X-ray Sources by Circumbinary Material - A Way to Hide Type Ia Supernova Progenitors?
The progenitors of supernovae (SNe) type Ia are usually assumed to be either
a single white dwarf (WD) accreting from a non-degenerate companion (the SD
channel) or the result of two merging WDs (DD channel). However, no consensus
currently exists as to which progenitor scenario is the correct one, or whether
the observed SN Ia rate is produced by a combination of both channels. Unlike a
DD progenitor a SD progenitor is expected to emit supersoft X-rays for a
prolonged period of time (~1 Myr) as a result of the burning of accreted matter
on the surface of the WD. An argument against the SD channel as a significant
producer of SNe type Ia has been the lack of observed supersoft X-ray sources
(SSS) and the lower-than-expected integrated soft X-ray flux from elliptical
galaxies.
We wish to determine if it is possible to obscure the supersoft X-ray
emission from a nuclear burning white dwarf in an accreting single degenerate
binary system. In case of obscured systems we wish to determine their general
observational characteristics.
We examine the emergent X-ray emission from a canonical SSS system surrounded
by a spherically symmetric configuration of material, assuming a black body
spectrum with T_BB=50 eV and L=10^38 erg/s. The circumbinary material is
assumed to be of solar chemical abundances, and we leave the mechanism behind
the mass loss into the circumbinary region unspecified.
If steadily accreting, nuclear burning WDs are canonical SSS our analysis
suggests that they can be obscured by relatively modest circumbinary mass loss
rates. This may explain the discrepancy of SSS compared to the SN Ia rate
inferred from observations if the SD progenitor scenario contributes
significantly to the SN Ia rate. Recycled emissions from obscured systems may
be visible in other wavebands than X-rays. It may also explain the lack of
observed SSS in symbiotic binary systems.Comment: 10 pages, 4 figures, accepted A&
Design choices for observational studies of the effect of exposure on disease incidence.
The purpose of this paper is to help readers choose an appropriate observational study design for measuring an association between an exposure and disease incidence. We discuss cohort studies, sub-samples from cohorts (case-cohort and nested case-control designs), and population-based or hospital-based case-control studies. Appropriate study design is the foundation of a scientifically valid observational study. Mistakes in design are often irremediable. Key steps are understanding the scientific aims of the study and what is required to achieve them. Some designs will not yield the information required to realise the aims. The choice of design also depends on the availability of source populations and resources. Choosing an appropriate design requires balancing the pros and cons of various designs in view of study aims and practical constraints. We compare various cohort and case-control designs to estimate the effect of an exposure on disease incidence and mention how certain design features can reduce threats to study validity
High angular resolution N-band observation of the silicate carbon star IRAS08002-3803 with the VLTI/MIDI instrument
We present the results of N-band spectro-interferometric observations of the
silicate carbon star IRAS08002-3803 with the MID-infrared Interferometric
instrument (MIDI) at the Very Large Telescope Interferometer (VLTI) of the
European Southern Observatory (ESO). The observations were carried out using
two unit telescopes (UT2 and UT3) with projected baseline lengths ranging from
39 to 47 m. Our observations of IRAS08002-3803 have spatially resolved the
dusty environment of a silicate carbon star for the first time and revealed an
unexpected wavelength dependence of the angular size in the N band: the
uniform-disk diameter is found to be constant and ~36 mas (72 Rstar) between 8
and 10 micron, while it steeply increases longward of 10 micron to reach ~53
mas (106 Rstar) at 13 micron. Model calculations with our Monte Carlo radiative
transfer code show that neither spherical shell models nor axisymmetric disk
models consisting of silicate grains alone can simultaneously explain the
observed wavelength dependence of the visibility and the spectral energy
distribution (SED). We propose that the circumstellar environment of
IRAS08002-3803 may consist of two grain species coexisting in the disk:
silicate and a second grain species, for which we consider amorphous carbon,
large silicate grains, and metallic iron grains. Comparison of the observed
visibilities and SED with our models shows that such disk models can fairly --
though not entirely satisfactorily -- reproduce the observed SED and N-band
visibilities. Our MIDI observations and the radiative transfer calculations
lend support to the picture where oxygen-rich material around IRAS08002-3803 is
stored in a circumbinary disk surrounding the carbon-rich primary star and its
putative low-luminosity companion.Comment: 15 pages, 8 figures, accepted for publication in A&
Arguably big biology: Sociology, spatiality and the knockout mouse project
© 2013 copyright Palgrave MacmillanThis is a post-peer-review, pre-copyedit version of an article published in BioSocieties. The definitive publisher-authenticated version BioSocieties, 2013, Vol. 8, pp. 417-431 is available online at: http://www.palgrave-journals.com/biosoc/journal/v8/n4/full/biosoc201325a.htmlFollowing the completion of the Human Genome Project (HGP), a critical challenge has been how to make biological sense of the amassed sequence data and translate this into clinical applications. A range of large biological research projects, as well as more distributed experimental collaborations, are seeking to realise this through translational research initiatives and postgenomic approaches. Drawing on interviews with key participants, this article explores the biological assumptions, sociological challenges and spatial imaginaries at play in arguments around one of these developments, which is using genetically altered mice to understand gene function. The knockout mouse project (KOMP) is a large-scale initiative in functional genomics, seeking to produce a âknockout mouseâ for each gene in the mouseâs genome, which can then be used to answer questions about gene function in mammals. KOMP is frequently framed as one successor to the HGP, emblematic of the ambitions of internationally coordinated biological research. However, the development of new technologies for generating and managing genetically altered mice, alongside the challenge of asking biologically meaningful questions of vast numbers of animals, is creating new frictions in this extension and intensification of biological research practices. This article introduces two separate approaches to the future of international research using mutant mice as stakeholders to negotiate the biological, sociological and spatial challenges of collaboration. The first centres on the directed research practices and sociological assumptions of KOMP, as individual researchers are reorganised around shared animals, databases and infrastructures. The second highlights an alternative vision of the future of biomedical research, using distributed management to enhance the sensitivities and efficiencies of existing experimental practices over space. These exemplify two different tactics in the organisation of an âarguablyâ big biology. They also critically embody different sociological and spatial imaginaries for the collaborative practices of international translational research
C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth
Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7
intermediate-mass Herbig Ae stars with circumstellar disks were obtained using
the Spitzer Space Telescope as part of the c2d IRS survey. This work
complements prior spectroscopic studies of silicate infrared emission from
disks, which were focused on intermediate-mass stars, with observations of
solar-mass stars limited primarily to the 10 um region. The observed 10 and 20
um silicate feature strengths/shapes are consistent with source-to-source
variations in grain size. A large fraction of the features are weak and flat,
consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um
in radius). In addition, approximately half of the T Tauri star spectra show
crystalline silicate features near 28 and 33 um indicating significant
processing when compared to interstellar grains. A few sources show large
10-to-20 um ratios and require even larger grains emitting at 20 um than at 10
um. This size difference may arise from the difference in the depth into the
disk probed by the two silicate emission bands in disks where dust settling has
occurred. The 10 um feature strength vs. shape trend is not correlated with age
or Halpha equivalent width, suggesting that some amount of turbulent mixing and
regeneration of small grains is occurring. The strength vs. shape trend is
related to spectral type, however, with M stars showing significantly flatter
10 um features (larger grain sizes) than A/B stars. The connection between
spectral type and grain size is interpreted in terms of the variation in the
silicate emission radius as a function of stellar luminosity, but could also be
indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation,
stellar/disk winds, etc.).Comment: 17 pages, 13 figures, accepted for publication by ApJ, formatted with
emulateapj using revtex4 v4.
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