1,510 research outputs found

    A METHOD COMPARISON STUDY OF ACCELEROMETER BASED BLOCK RESPONSE TIMES IN SPRINTING

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    This study aimed to provide a method comparison of a rail mounted accelerometer for detection of block response-times (RT) with an International Association of Athletic Federation (IAAF) approved automatic start control system (IAAF RT). Twenty national and international sprinters completed sprint trials under simulated race conditions. An accelerometer was placed on the block rail of blocks and RT was determined using visual inspection of the accelerometer signal and using a 3SD threshold method. On average, the visual method detected the RT event 7 ms before, and the 3SD method detected RT 1 ms after the IAAF RT. The results indicated close agreement between the 3SD threshold method and the IAAF RT, however, this highlights the need for further re-examination of threshold-based detection algorithms which may delay the detection of the RT event

    FUNCTIONAL DATA ANALYSIS OF THE KINEMATICS OF GAIT IN SUBJECTS WITH A HISTORY OF ACHILLES TENDON INJURY

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    Clinical biomechanics research aims to understand the mechanisms of injury to improve prediction, prevention and rehabilitation. Dynamical systems theory suggests that coordination and variability may be key issues in the development of injuries. Traditional analysis has relied on a multivariate approach using discrete measures during stance. This essentially discards kinematic data obtained throughout the entire stance phase. Functional data analysis is an established statistical technique that is now emerging in biomechanics. It views the data as a function, thus using the entire time series data and determines which factors contribute to the variation. The purpose of this study was to examine the predictions of dynamical systems theory on angular kinematic data in subjects with Achilles tendon injury using a functional data analysis approach

    Microbicides development programme: engaging the community in the standard of care debate in a vaginal microbicide trial in Mwanza, Tanzania.

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    BACKGROUND: HIV prevention research in resource-limited countries is associated with a variety of ethical dilemmas. Key amongst these is the question of what constitutes an appropriate standard of health care (SoC) for participants in HIV prevention trials. This paper describes a community-focused approach to develop a locally-appropriate SoC in the context of a phase III vaginal microbicide trial in Mwanza City, northwest Tanzania. METHODS: A mobile community-based sexual and reproductive health service for women working as informal food vendors or in traditional and modern bars, restaurants, hotels and guesthouses has been established in 10 city wards. Wards were divided into geographical clusters and community representatives elected at cluster and ward level. A city-level Community Advisory Committee (CAC) with representatives from each ward has been established. Workshops and community meetings at ward and city-level have explored project-related concerns using tools adapted from participatory learning and action techniques e.g. chapati diagrams, pair-wise ranking. Secondary stakeholders representing local public-sector and non-governmental health and social care providers have formed a trial Stakeholders' Advisory Group (SAG), which includes two CAC representatives. RESULTS: Key recommendations from participatory community workshops, CAC and SAG meetings conducted in the first year of the trial relate to the quality and range of clinic services provided at study clinics as well as broader standard of care issues. Recommendations have included streamlining clinic services to reduce waiting times, expanding services to include the children and spouses of participants and providing care for common local conditions such as malaria. Participants, community representatives and stakeholders felt there was an ethical obligation to ensure effective access to antiretroviral drugs and to provide supportive community-based care for women identified as HIV positive during the trial. This obligation includes ensuring sustainable, post-trial access to these services. Post-trial access to an effective vaginal microbicide was also felt to be a moral imperative. CONCLUSION: Participatory methodologies enabled effective partnerships between researchers, participant representatives and community stakeholders to be developed and facilitated local dialogue and consensus on what constitutes a locally-appropriate standard of care in the context of a vaginal microbicide trial in this setting. TRIAL REGISTRATION: Current Controlled Trials ISRCTN64716212

    Increased attractiveness of honeybee hive product volatiles to adult small hive beetle, Aethina tumida, resulting from small hive beetle larval infestation

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    The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a recent but significant pest of honeybee Apis mellifera L. (Hymenoptera: Apidae) hives in various regions throughout the world, including Eastern Australia. The larval stage of this beetle damages hives when they feed on brood, pollen, and honeycomb, leaving behind fermented wastes. In cases of extreme damage, hives collapse and are turned to an odorous mass of larvae in fermenting hive products. The yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Ascomycota) has been consistently isolated from the fermenting material as well as each life stage of this beetle. Various studies have noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast K. ohmeri, although earlier studies have not used naturally occurring hive products as their source of fermentation. This study investigated changes through time in the attractiveness of natural honeybee hive products to the small hive beetle as the hive products were altered by the action of beetle larvae and fermentation by K. ohmeri. We used gas chromatography-mass spectrometry and choice-test behavioural assays to investigate these changes using products sampled from three apiaries. Attractiveness of the fermenting hive products (‘slime’) increased as fermentation progressed, and volatile profiles became more complex. Fermenting hive products remained extremely attractive for more than 30 days, significantly longer than previous reports. These results have strong implications for the development of an external attractant trap to assist in the management of this invasive pest

    SPSS and SAS procedures for estimating indirect effects in simple mediation models

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    Researchers often conduct mediation analysis in order to indirectly assess the effect of a proposed cause on some outcome through a proposed mediator. The utility of mediation analysis stems from its ability to go beyond the merely descriptive to a more functional understanding of the relationships among variables. A necessary component of mediation is a statistically and practically significant indirect effect. Although mediation hypotheses are frequently explored in psychological research, formal significance tests of indirect effects are rarely conducted. After a brief overview of mediation, we argue the importance of directly testing the significance of indirect effects and provide SPSS and SAS macros that facilitate estimation of the indirect effect with a normal theory approach and a bootstrap approach to obtaining confidence intervals, as well as the traditional approach advocated by Baron and Kenny (1986). We hope that this discussion and the macros will enhance the frequency of formal mediation tests in the psychology literature. Electronic copies of these macros may be downloaded from the Psychonomic Society's Web archive at www.psychonomic.org/archive/

    Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individuals

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    Eccentric exercise-induced damage leads to reductions in muscle force, increased soreness, and impaired muscle function. Creatine monohydrate's (Cr) ergogenic potential is well established; however few studies have directly examined the effects of Cr supplementation on recovery after damage. We examined the effects of Cr supplementation on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. The major finding of this investigation was a significant improvement in the rate of recovery of knee extensor muscle function after Cr supplementation following injury

    Long-term Holocene groundwater fluctuations in a chalk catchment: evidence from Rock-Eval pyrolysis of riparian peats

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    he depositional history of peat-dominated wetlands can be used to understand palaeoclimate and palaeohydrology and also constrain the impacts of future climate change. However, in chalkland valleys, seasonal water table fluctuations and a high alkalinity have diminished key environment indicators such as pollen, and there is a need for alternative investigative techniques. The method of Rock-Eval pyrolysis can track changes in organic matter source and degradation, potentially relating to historic changes in vegetation cover. This is the first Rock-Eval on cores from a groundwater-dependent riparian chalk valley wetland combined with radiocarbon dating. The dating showed that the cores represented approximately 4000 years of depositional history. Changes in hydrocarbon chemistry including normal alkane composition of the peat indicated shifts of around 500 to 1000 years between terrestrial and more aquatic species, relating to periods of climate wetness. These climatic shifts are broadly consistent with other evidence from ombrotrophic peatland and lacustrine sediments across northwest Europe. However, the connection between climate wetness and groundwater dependent chalkland wetlands is complicated by external anthropogenically driven factors relating to land use and vegetation cover changes in the catchment. Nonetheless, this study suggests that Rock-Eval pyrolysis is a useful and cost-effective tool that can provide evidence for long-term Holocene groundwater fluctuation

    Atypical biological kinematics are represented during observational practice

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    The present study investigated the effect of stimulus-response compatibility on the representation of atypical biological kinematics during observational practice. A compatible group observed an atypical model that moved rightwards, whereas an incompatible group observed an atypical model that moved leftwards. Both groups were instructed to observe the model with the intention to later reproduce the movement trajectory. This was examined in a post-test where participants were asked to move rightwards with a kinematic profile that matched the atypical kinematics. Compared to a control group that did not engage in practice, and irrespective of whether the stimulus was observed in a spatially compatible or incompatible orientation, participants from both experimental groups reproduced velocity profiles that were comparable, and similar to the atypical biological kinematics. Bayesian analysis indicated equality between the two experimental groups, thus suggesting comparable sensorimotor processing. Therefore, by rotating the incompatible stimulus by 180 degrees during observational practice, the current study has isolated the processing and representation of atypical biological kinematics to the underlying sensorimotor processes, rather than spatial encoding of peak velocity via processes associated with stimulus-response compatibility
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