153 research outputs found
Influence of Speed, Ground Surface and Shoeing Condition on Hoof Breakover Duration in Galloping Thoroughbred Racehorses
Understanding the effect of horseshoeâsurface combinations on hoof kinematics at gallop is relevant for optimising performance and minimising injury in racehorseâjockey dyads. This intervention study assessed hoof breakover duration in Thoroughbred ex-racehorses from the British Racing School galloping on turf and artificial tracks in four shoeing conditions: aluminium, barefoot, aluminiumârubber composite (GluShu) and steel. Shoeâsurface combinations were tested in a randomized order and horseâjockey pairings (n = 14) remained constant. High-speed video cameras (Sony DSC-RX100M5) filmed the hoof-ground interactions at 1000 frames per second. The time taken for a hoof marker wand fixed to the lateral hoof wall to rotate through an angle of 90 degrees during 384 breakover events was quantified using Tracker software. Data were collected for leading and non-leading forelimbs and hindlimbs, at gallop speeds ranging from 23â56 km hâ1. Linear mixed-models assessed whether speed, surface, shoeing condition and any interaction between these parameters (fixed factors) significantly affected breakover duration. Day and horseâjockey pair were included as random factors and speed was included as a covariate. The significance threshold was set at p \u3c 0.05. For all limbs, breakover times decreased as gallop speed increased (p \u3c 0.0005), although a greater relative reduction in breakover duration for hindlimbs was apparent beyond approximately 45 km hâ1. Breakover duration was longer on turf compared to the artificial surface (p †0.04). In the non-leading hindlimb only, breakover duration was affected by shoeing condition (p = 0.025) and an interaction between shoeing condition and speed (p = 0.023). This work demonstrates that speed, ground surface and shoeing condition are important factors influencing the galloping gait of the Thoroughbred racehorse
Understanding the association between negative symptoms and performance on effort-based decision-making tasks: The importance of defeatist performance beliefs
Effort-based decision-making paradigms are increasingly utilized to gain insight into the nature of motivation deficits. Research has shown associations between effort-based decision making and experiential negative symptoms; however, the associations are not consistent. The current study had two primary goals. First, we aimed to replicate previous findings of a deficit in effort-based decision making among individuals with schizophrenia on a test of cognitive effort. Second, in a large sample combined from the current and a previous study, we sought to examine the association between negative symptoms and effort by including the related construct of defeatist beliefs. The results replicated previous findings of impaired cognitive effort-based decision making in schizophrenia. Defeatist beliefs significantly moderated the association between negative symptoms and effort-based decision making such that there was a strong association between high negative symptoms and deficits in effort-based decision making, but only among participants with high levels of defeatist beliefs. Thus, our findings suggest the relationship between negative symptoms and effort performance may be understood by taking into account the role of defeatist beliefs, and finding that might explain discrepancies in previous studies
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Using Automated Health Plan Data to Assess Infection Risk from Coronary Artery Bypass Surgery
We determined if infection indicators were sufficiently consistent across health plans to allow comparison of hospitalsâ risks of infection after coronary artery bypass surgery. Three managed care organizations accounted for 90% of managed care in eastern Massachusetts, from October 1996 through March 1999. We searched automated inpatient and outpatient claims and outpatient pharmacy dispensing files for indicator codes suggestive of postoperative surgical site infection. We reviewed full text medical records of patients with indicator codes to confirm infection status. We compared the hospital-specific proportions of cases with an indicator code, adjusting for health plan, age, sex, and chronic disease score. A total of 536 (27%) of 1,953 patients had infection indicators. Infection was confirmed in 79 (53%) of 149 reviewed records with adequate documentation. The proportion of patients with an indicator of infection varied significantly (p<0.001) between hospitals (19% to 36%) and health plans (22% to 33%). The difference between hospitals persisted after adjustment for health plan and patientsâ age and sex. Similar relationships were observed when postoperative antibiotic information was ignored. Automated claims and pharmacy data from different health plans can be used together to allow inexpensive, routine monitoring of indicators of postoperative infection, with the goal of identifying institutions that can be further evaluated to determine if risks for infection can be reduced
Increased Stability of PFSA Proton Exchange Membranes Under Fuel Cell Operation by the Decomposition of Peroxide Catalyzed by Heteropoly Acids
Abstract Proton exchange membranes were cast from mixtures of the 3M perfluorinated sulfonic acid ionomer, with side chain -O-(CF 2 ) 4 -SO 3 H, and various heteropoly acids (HPAs) at a 10 or 20 wt% doping level. The membrane electrode assemblies (MEAs) prepared from these membranes were subjected to a fuel cell testing protocol involving incubation to steady state, temperature challenge, accelerated testing, and post mortem analysis. The cell temperature was varied from 70 -100 ÂșC under relatively dry conditions, 70 ÂșC dewpoint, to avoid leaching of the HPA. The most important finding from this study was that the mor
Enhanced Identification of Postoperative Infections among Outpatients
Claims data complement other data sources for identification of surgical site infections following breast surgery and cesarean section
Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment
ARGO-YBJ is an air shower detector array with a fully covered layer of
resistive plate chambers. It is operated with a high duty cycle and a large
field of view. It continuously monitors the northern sky at energies above 0.3
TeV. In this paper, we report a long-term monitoring of Mrk 421 over the period
from 2007 November to 2010 February. This source was observed by the
satellite-borne experiments Rossi X-ray Timing Explorer and Swift in the X-ray
band. Mrk 421 was especially active in the first half of 2008. Many flares are
observed in both X-ray and gamma-ray bands simultaneously. The gamma-ray flux
observed by ARGO-YBJ has a clear correlation with the X-ray flux. No lag
between the X-ray and gamma-ray photons longer than 1 day is found. The
evolution of the spectral energy distribution is investigated by measuring
spectral indices at four different flux levels. Hardening of the spectra is
observed in both X-ray and gamma-ray bands. The gamma-ray flux increases
quadratically with the simultaneously measured X-ray flux. All these
observational results strongly favor the synchrotron self-Compton process as
the underlying radiative mechanism.Comment: 30 pages, 8 figure
Observations of Milky Way Dwarf Spheroidal galaxies with the Fermi-LAT detector and constraints on Dark Matter models
We report on the observations of 14 dwarf spheroidal galaxies with the Fermi
Gamma-Ray Space Telescope taken during the first 11 months of survey mode
operations. The Fermi telescope provides a new opportunity to test particle
dark matter models through the expected gamma-ray emission produced by pair
annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf
spheroidal galaxies, the largest galactic substructures predicted by the cold
dark matter scenario, are attractive targets for such indirect searches for
dark matter because they are nearby and among the most extreme dark matter
dominated environments. No significant gamma-ray emission was detected above
100 MeV from the candidate dwarf galaxies. We determine upper limits to the
gamma-ray flux assuming both power-law spectra and representative spectra from
WIMP annihilation. The resulting integral flux above 100 MeV is constrained to
be at a level below around 10^-9 photons cm^-2 s^-1. Using recent stellar
kinematic data, the gamma-ray flux limits are combined with improved
determinations of the dark matter density profile in 8 of the 14 candidate
dwarfs to place limits on the pair annihilation cross-section of WIMPs in
several widely studied extensions of the standard model. With the present data,
we are able to rule out large parts of the parameter space where the thermal
relic density is below the observed cosmological dark matter density and WIMPs
(neutralinos here) are dominantly produced non-thermally, e.g. in models where
supersymmetry breaking occurs via anomaly mediation. The gamma-ray limits
presented here also constrain some WIMP models proposed to explain the Fermi
and PAMELA e^+e^- data, including low-mass wino-like neutralinos and models
with TeV masses pair-annihilating into muon-antimuon pairs. (Abridged)Comment: 25 pages, 4 figures, accepted to ApJ, Corresponding authors: J.
Cohen-Tanugi, C. Farnier, T.E. Jeltema, E. Nuss, and S. Profum
Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe
The Extragalactic Background Light (EBL) includes photons with wavelengths
from ultraviolet to infrared, which are effective at attenuating gamma rays
with energy above ~10 GeV during propagation from sources at cosmological
distances. This results in a redshift- and energy-dependent attenuation of the
gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts
(GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray
blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using
photons above 10 GeV collected by Fermi over more than one year of observations
for these sources, we investigate the effect of gamma-ray flux attenuation by
the EBL. We place upper limits on the gamma-ray opacity of the Universe at
various energies and redshifts, and compare this with predictions from
well-known EBL models. We find that an EBL intensity in the optical-ultraviolet
wavelengths as great as predicted by the "baseline" model of Stecker et al.
(2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication
in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A.
Reimer, L.C. Reye
Contextualising the pervasive impact of macroeconomic austerity on prison health in England: A qualitative study among international policymakers
Background: Prisons offer the state the opportunity to gain access to a population that is at particularly high risk of ill-health. Despite the supportive legal and policy structures surrounding prison rehabilitation, the oppressive nature of the austerity policy in England threatens its advanced improvement.Methods: Using grounded theory methodology, this is the first interdisciplinary qualitative study to explore the impact of macroeconomic austerity on prison health in England from the perspective of 29 international prison policymakers.Results: The far-reaching impact of austerity in England has established a regressive political system that shapes the societal attitude towards social issues, which has exacerbated the existing poor health of the prisoners. Austerity has undermined the notion of social collectivism, imposed a culture of acceptance among prison bureaucrats and the wider community, and normalised the devastating impacts of prison instability. These developments are evidenced by the increasing levels of suicide, violence, radicalisation and prison gangs among prisoners, as well as the imposition of long working hours and the high levels of absenteeism among prison staff.Conclusions: This study underscores an important and yet unarticulated phenomenon that despite being the fifth largest economy in the world, Englandâs poorest, marginalised and excluded population continues to bear the brunt of austerity. Reducing the prison population, using international obligations as minimum standards to protect prisonersâ right to health and providing greater resources would create a more positive and inclusive system, in line with Englandâs international and domestic commitments to the humane treatment of all people
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