1,027 research outputs found
Legitimacy driven change at the World Anti-Doping Agency
The effectiveness of the World Anti-Doping Agency as an international non-governmental
organisation with a mission to regulate anti-doping policy has been challenged before by
doping scandals in sport. Historically, anti-doping policy development has been primarily
reactive, determined by the need for dominant organisations to maintain power rather than to
protect athletes. The purpose of this paper is to explore reactive anti-doping policy change
from a multi-level legitimacy perspective. Using multi-level legitimacy theory and the
concept of legitimacy challenges, it is argued that reactive policy change is motivated by a
need to manage perceived organisational legitimacy. The recent exposure of systematic
doping in Russia is used as an example to support this analysis. These findings are discussed
in the context of current criticisms of anti-doping policy
Desperate planktotrophs : decreased settlement selectivity with age in competent eastern oyster Crassostrea virginica larvae
Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 599 (2018): 93-106, doi:10.3354/meps12653.For larvae of benthic marine invertebrate species, settlement from planktonic to benthic
life is a critical transition. The “desperate larva” concept describes the tendency of larvae to
accept suboptimal settlement habitats as they age. We quantified swimming behavior in
planktotrophic larvae of the eastern oyster, Crassostrea virginica, to determine whether
settlement behaviors, such as swimming downward and remaining on the bottom, increased with
age and whether these ontogenetic changes were more apparent in larvae exposed to suboptimal
conditions than to preferred conditions (settlement cue absent or present, respectively). In two
experiments, the proportion of competent larvae remaining near the bottom of experimental
flasks (indicating settlement) increased with larval age, but only in larvae that were not exposed
to the settlement cue. This result is consistent with the hypothesis that larvae encountering
suboptimal habitat become “desperate” (i.e. more likely to settle) as they age. Exploratory
behaviors, such as upward swimming, meandering, or helices, were expected to decrease with
age, especially in the absence of the settlement cue, but this pattern was detected in only one of
the five swimming metrics tested (helices in downward swimming larvae). Surprisingly, pre-competent larvae exhibited settlement behavior when exposed to the cue, raising the question of
whether a response at this stage would have positive or negative consequences. Acceptance of
suboptimal settlement habitats by aging larvae may increase the resilience of a species by
allowing populations to persist in variable environmental conditions.Funding was provided by NSF grant OCE-0850419, NOAA Sea Grant
NA14OAR4170074, grants from WHOI Coastal Ocean Institute, discretionary WHOI funds, a
WHOI Ocean Life Fellowship to LSM, a WHOI Summer Student Fellowship to EH, and a
WHOI Postdoctoral Scholarship to KSM
Experimental investigation of a bistable system in the presence of noise and delay
We experimentally analyze the behavior of a non-Markovian bistable system with noise, using a vertical cavity surface emitting laser with time-delayed optoelectronic feedback. The effects of the delayed feedback are observed in the probability distribution of the residence times of the two orthogonal polarization states, and in the polarization-resolved power spectrum. They agree well with recent theoretical predictions based on a two-state model with transition rates depending on an earlier state of the system. We also observe experimentally and explain theoretically that the residence time probability distribution deviates from exponential decay for residence times close to (and smaller than) the delay time.Peer ReviewedPostprint (published version
Targeting Mr Average: Participation, gender equity and school sport partnerships
The School Sport Partnership Programme (SSPP) is one strand of the national strategy for physical education and school sport in England, the physical education and school sport Club Links Strategy (PESSCL). The SSPP aims to make links between school physical education (PE) and out of school sports participation, and has a particular remit to raise the participation levels of several identified under-represented groups, of which girls and young women are one. National evaluations of the SSPP show that it is beginning to have positive impacts on young people's activity levels by increasing the range and provision of extra curricular activities (Office for Standards in Education (OFSTED), 2003, 2004, 2005; Loughborough Partnership, 2005, 2006). This paper contributes to the developing picture of the phased implementation of the programme by providing qualitative insights into the work of one school sport partnership with a particular focus on gender equity. The paper explores the ways in which gender equity issues have been explicitly addressed within the 'official texts' of the SSPP; how these have shifted over time and how teachers are responding to and making sense of these in their daily practice. Using participation observation, interview and questionnaire data, the paper explores how the coordinators are addressing the challenge of increasing the participation of girls and young women. The paper draws on Walby's (2000) conceptualisation of different kinds of feminist praxis to highlight the limitations of the coordinators' work. Two key themes from the data and their implications are addressed: the dominance of competitive sport practices and the PE professionals' views of targeting as a strategy for increasing the participation of under-represented groups. The paper concludes that coordinators work within an equality or difference discourse with little evidence of the transformative praxis needed for the programme to be truly inclusive. © 2008 Taylor & Francis
Pneumococcal conjugate vaccine dose-ranging studies in humans: A systematic review
Background:
Streptococcus pneumoniae is one of the most common bacterial pathogens of infants and young children. Antibody responses against the pneumococcal polysaccharide capsule are the basis of vaccine-mediated protection. We examined the relationship between the dose of polysaccharide in pneumococcal conjugate vaccines (PCVs) and immunogenicity.
Methods:
A systematic search of English publications that evaluated the immunogenicity of varying doses of pneumococcal conjugate vaccines was performed in Medline and Embase (Ovid Sp) databases in August 2019. We included only articles that involved administration of pneumococcal conjugate vaccine in humans and assessed the immunogenicity of more than one serotype-specific saccharide dose. Results were synthesised descriptively due to the heterogeneity of product valency, product content and vaccine schedule.
Results:
We identified 1691 articles after de-duplication; 9 studies met our inclusion criteria; 2 in adults, 6 in children and 1 in both. Doses of polysaccharide evaluated ranged from 0.44 mcg to 17.6 mcg. In infants, all doses tested elicited IgG geometric mean concentrations (GMCs) above the established correlate of protection (COP; 0.35 mcg/ml). A month after completion of the administered vaccine schedule, 95% confidence intervals of only three out of all the doses evaluated had GMCs that crossed below the COP. In the adult studies, all adults achieved GMCs that would be considered protective in children who have received 3 standard vaccine doses.
Conclusion:
For some products, the mean antibody concentrations induced against some pneumococcal serotypes increased with increasing doses of the polysaccharide conjugate, but for other serotypes, there were no clear dose–response relationships or the dose response curves were negative. Fractional doses of polysaccharide which contain less than is included in currently distributed formulations may be useful in the development of higher valency vaccines, or dose-sparing delivery for paediatric use
Electron and hole dynamics of InAs/GaAs quantum dot semiconductor optical amplifiers
Single-color and two-color pump-probe measurements are used to analyze carrier dynamics in InAs/GaAs quantum dot amplifiers. The study reveals that hole recovery and intradot electron relaxation occur on a picosecond time scale, while the electron capture time is on the order of 10 ps. A longer time scale of hundreds of picoseconds is associated with carrier recovery in the wetting layer, similar to that observed in quantum well semiconductor amplifiers. (c) 2007 American Institute of Physics. (DOI:10.1063/1.2771374
Carrier capture dynamics of InAs/GaAs quantum dots
Carrier dynamics of a 1.3 mu m InAs/GaAs quantum dot amplifier is studied using heterodyne pump-probe spectroscopy. Measurements of the recovery times versus injection current reveal a power law behavior predicted by a quantum dot rate equation model. These results indicate that Auger processes dominate the carrier dynamics. (c) 2007 American Institute of Physics. (DOI:10.1063/1.2715115
Reward Differences Between Adolescents From A Native American Community And Adolescents From A Non-Native American Community
Differences in preferred rewards of male and female Native American and non-Native America adolescents were examined using the Native American version of the Survey of Rewards for Teens (SORT-NA). The SORT-NA is a self-report survey which examines preferences across eight domains: sports, food, entertainment, excursions, interests and hobbies, social activities, social related activities, and a miscellaneous category. Results indicated significant differences in reward preference across culture in two domains, and across gender in five domains
A comparison of transient elastography with acoustic radiation force impulse elastography for the assessment of liver health in patients with chronic hepatitis C: Baseline results from the TRACER study
BACKGROUND: Liver stiffness measurements can be used to assess liver fibrosis and can be acquired by transient elastography using FibroScan® and with Acoustic Radiation Force Impulse imaging. The study aimed to establish liver stiffness measurement scores using FibroScan® and Acoustic Radiation Force Impulse in a chronic hepatitis C cohort and to explore the correlation and agreement between the scores and the factors influencing agreement. METHODS: Patients had liver stiffness measurements acquired with FibroScan® (right lobe of liver) and Acoustic Radiation Force Impulse (right and left lobe of liver). We used Spearman’s correlation to explore the relationship between FibroScan® and Acoustic Radiation Force Impulse scores. A Bland–Altman plot was used to evaluate bias between the mean percentage differences of FibroScan® and Acoustic Radiation Force Impulse scores. Univariable and multivariable analyses were used to assess how factors such as body mass index, age and gender influenced the agreement between liver stiffness measurements. RESULTS: Bland-Altman showed the average (95% CI) percentage difference between FibroScan® and Acoustic Radiation Force Impulse scores was 27.5% (17.8, 37.2), p < 0.001. There was a negative correlation between the average and percentage difference of the FibroScan® and Acoustic Radiation Force Impulse scores (r (95% CI) = −0.41 (−0.57, −0.21), p < 0.001), thus showing that percentage difference gets smaller for greater FibroScan® and Acoustic Radiation Force Impulse scores. Body mass index was the biggest influencing factor on differences between FibroScan® and Acoustic Radiation Force Impulse (r = 0.12 (0.01, 0.23), p = 0.05). Acoustic Radiation Force Impulse scores at segment 5/8 and the left lobe showed good correlation (r (95% CI) = 0.83 (0.75, 0.89), p < 0.001). CONCLUSION: FibroScan® and Acoustic Radiation Force Impulse had similar predictive values for the assessment of liver stiffness in patients with chronic hepatitis C infection; however, the level of agreement varied across lower and higher scores
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