3,972 research outputs found

    Effects of different footwear on landing forces from a grand jeté in trained dancers

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    The Grand Jete movement is a popular leap elevation movement used in ballet, modern, contemporary and jazz dance. The move involves taking off from one foot and landing on the other foot reaching the highest point possible in the air and lifting legs to a split position. Dancers may perform many grand jetes in a single routine. The aim of this study was to investigate whether footwear used by dancers can reduce the vertical impact forces caused by landing from high leaps. The study was approved by the university’s ethics committee and informed consent was given by ten highly-trained dancers (age mean 23.1, s=1.6 years; height 1.64, s=.08 m; mass 57.7, s=5.2 kg). The participants all performed a grand jete in three different footwear conditions: bare feet, jazz shoes and dance trainers with shock absorbing properties. Landing forces were recorded using a Kistler force plate sampling at 1000 Hz. Peak impact force was determined as the maximum vertical force occurring during the first 0.07 s of contact. Statistical analysis consisted of repeated measures ANOVA. Maximumforce during the landing phase decreased from 4.00 BW (s=0.72) in the barefoot condition to 3.95 BW (s=0.69) in the jazz shoes condition and 3.58 BW (s=0.68) in the trainers condition (F2,9=2.5, P=0.108, Z2=0.22, power=0.44).Higher impact peak and loading rate values were found in the barefoot condition compared to the shodconditions, with the trainers showing the lowest values. However, there were no significant differences between the footwear conditions for impact peak force(F2,9=0.50, P¼0.616, Z2=0.05, power=0.12),time-to-peak impact force (F2,9=0.44 , P=0.653, Z2=0.05, power=0.11), or loading rate to the poin of maximum vertical force (F2,9=0.53, P=0.597, Z2=0.06, power=0.12). The results showed lower maximum landing forces, impact peak force and loading rates in the dance trainers compared to the barefoot and jazz shoes conditions. Although the values were not significantly different, the small difference between footwear conditions may prove important with the onset of fatigue during a routine. Dancers should train to develop safe landing techniques when performing barefooted

    Kinematic differences between defended and undefended shots in netball

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    Successful shooting in netball depends not only on achieving the correct angle, velocity and height of release, but also on how well the shooter can adjust these factors when faced with a defender. However, few studies, if any, have analysed the difference between shots taken with a defender present and those without (usually due to a penalty against the defender). The aim of the study was to examine the difference in kinematic variables between defended and undefended shots during netball games. The study was approved by the university’s ethics committee and informed consent was given by eight elite netballers (age mean 22.1, s=2.3 years; stature 1.81, s=.08 m; mass 69.0, s=8.7 kg). Each participant was filmed playing in a Netball Superleague game during the 2007/2008 season. Two stationary Canon DM-XL1 digital cameras were placed on a balcony overlooking the playing area, so as not to interfere with the players or spectators. The sampling rate was 50 Hz, and the shutter speed 1/500 s. Two successful shots per player were digitised and analysed using SIMI Motion (Munich) and filtered using a Butterworth low-pass 2nd order filter. The two shots consisted of one successful defended shot, and one successful undefended shot (due to a penalty awarded against the opposing team’s defender). Statistical analysis consisted of dependent t-tests. The height of release was higher for defended shots (2.16 m, s=0.28) than in undefended shots (1.93 m, s=0.04). This was caused partially due to greater elbow extension during the shooting action. The maximum elbow angle for defended shots was 138° (s=25) and for undefended shots 108° (s=23). The significant difference found between these values (P=0.049) was the only one found between the two shooting conditions. The angle of release at the shoulder was higher for defended shots (141°, s= 22) compared to undefended (133°, s=7), as was the vertical velocity of the wrist at release (0.54 m s -1, s=0.31 and 0.43 m s -1, s=0.12 respectively). Several differences were found between shooting with and without a defender, although only one was found to be significant. Nonetheless, it was clear that shooting with a defender present required a greater height of release, and larger shooting arm joint angles. It is important for netball players and coaches to shoot with defenders present during training in order to practice the style of shooting required during a game

    Variance in multiplex suspension array assays: A distribution generation machine for multiplex counts

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    <p>Abstract</p> <p>Background</p> <p>This study attempted to replicate Luminex experimental results for large numbers of beads per classifier using multiplexed assays and routine instrument use conditions.</p> <p>Conclusion</p> <p>Using larger numbers of microspheres per classifier highlights a fundamental stochastic distribution of bead counts issue complicated by other factors. The more classifiers and the higher the count required per classifier there are, the more apparent the distribution of counts per classifier will be, and the more microspheres are required. Additional problems have been identified. Alternate methods of improving precision and reliability are recommended such as intraplexing and multi-well sample replicates to improve precision and confidence.</p

    Evaluation of a patient and public involvement training programme for researchers at a large biomedical research centre in the UK

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    Objectives: To design, deliver and evaluate a programme of training workshops for biomedical researchers aimed at building confidence and skills in actively involving patients and the public (PPI) in research. Design: A bespoke programme of training workshops in PPI aimed at researchers. Setting: A large National Institute for Health Research Biomedical Research Centre in London and several partner organisations. Participants: 721 scientists, clinicians and research managers attending dedicated training in PPI at a major London NHS (National Health Service)–university partnership. Interventions: A programme of 72 training workshops, designed to build practical skills and confidence for researchers working with patients and the public in research, was delivered at a major research-active NHS:university partnership. An iterative approach was taken to the programme, with the content of the workshops continually reviewed and refreshed to respond to the needs of researchers. Surveys before, immediately following and 6 months after training investigated the impact on researchers’ confidence and skills in PPI work, and the kind of PPI they subsequently carried out. Results: Training brought about immediate marked increases in researchers’ self-reported confidence to carry out PPI activities within their research, and in their knowledge of good practice. The evaluation indicates that workshop attendees were more likely to involve patients in their research following training. Researchers tended to involve patients and the public in a range of areas, including input to study design and patient information, in particular. Conclusions: When positioned within a broader organisational strategy for PPI in research, such training has an important role to play in progressing PPI in a major research partnership. Training appeared to provide the confidence needed to carry out PPI which enabled further development of confidence and skills. Involving researchers who have attended the training in the ongoing development of the programme and bringing in patients to the training programme are key next steps

    System data communication structures for active-control transport aircraft, volume 2

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    The application of communication structures to advanced transport aircraft are addressed. First, a set of avionic functional requirements is established, and a baseline set of avionics equipment is defined that will meet the requirements. Three alternative configurations for this equipment are then identified that represent the evolution toward more dispersed systems. Candidate communication structures are proposed for each system configuration, and these are compared using trade off analyses; these analyses emphasize reliability but also address complexity. Multiplex buses are recognized as the likely near term choice with mesh networks being desirable for advanced, highly dispersed systems

    System data communication structures for active-control transport aircraft, volume 1

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    Candidate data communication techniques are identified, including dedicated links, local buses, broadcast buses, multiplex buses, and mesh networks. The design methodology for mesh networks is then discussed, including network topology and node architecture. Several concepts of power distribution are reviewed, including current limiting and mesh networks for power. The technology issues of packaging, transmission media, and lightning are addressed, and, finally, the analysis tools developed to aid in the communication design process are described. There are special tools to analyze the reliability and connectivity of networks and more general reliability analysis tools for all types of systems

    The Multi-Fungicide Resistance Status of Aspergillus fumigatus Populations in Arable Soils and the Wider European Environment

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    The evolution and spread of pan-azole resistance alleles in clinical and environmental isolates of Aspergillus fumigatus is a global human health concern. The identification of hotspots for azole resistance development in the wider environment can inform optimal measures to counteract further spread by minimizing exposure to azole fungicides and reducing inoculum build-up and pathogen dispersal. We investigated the fungicide sensitivity status of soil populations sampled from arable crops and the wider environment and compared these with urban airborne populations. Low levels of azole resistance were observed for isolates carrying the CYP51A variant F46Y/M172V/E427K, all belonging to a cluster of related cell surface protein (CSP) types which included t07, t08, t13, t15, t19, and t02B, a new allele. High levels of resistance were found in soil isolates carrying CYP51A variants TR34/L98H and TR46/Y121F/T289A, all belonging to CSP types t01, t02, t04B, or t11. TR46/Y121F/M172V/T289A/G448S (CSP t01) and TR46/Y121F/T289A/S363P/I364V/G448S (CSP t01), a new haplotype associated with high levels of resistance, were isolated from Dutch urban air samples, indicating azole resistance evolution is ongoing. Based on low numbers of pan-azole resistant isolates and lack of new genotypes in soils of fungicide-treated commercial and experimental wheat crops, we consider arable crop production as a coldspot for azole resistance development, in contrast to previously reported flower bulb waste heaps. This study also shows that, in addition to azole resistance, several lineages of A. fumigatus carrying TR-based CYP51A variants have also developed acquired resistance to methyl benzimidazole carbamate, quinone outside inhibitor and succinate dehydrogenase (Sdh) inhibitor fungicides through target-site alterations in the corresponding fungicide target proteins; beta-tubulin (F200Y), cytochrome b (G143A), and Sdh subunit B (H270Y and H270R), respectively. Molecular typing showed that several multi-fungicide resistant strains found in agricultural soils in this study were clonal as identical isolates have been found earlier in the environment and/or in patients. Further research on the spread of different fungicide-resistant alleles from the wider environment to patients and vice versa can inform optimal practices to tackle the further spread of antifungal resistance in A. fumigatus populations and to safeguard the efficacy of azoles for future treatment of invasive aspergillosis

    Outcomes After Bidirectional Cavopulmonary Shunt in Infants Less Than 6 Months Old

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    AbstractObjectives. We sought to assess the results after bidirectional cavopulmonary shunt (BCPS) in infants <6 months old and to identify risk factors for poor outcome.Background. Although BCPS is a well established procedure for the palliation of patients with a single-ventricle heart, there have been very few reports of outcomes after BCPS in young infants.Methods. Since 1990, 42 infants between 0.8 and 6.0 months of age (mean [±SD] 3.7 ± 1.4) have undergone BCPS for primary (n = 16) or secondary (n = 26) palliation of tricuspid atresia (n = 13), hypoplastic left heart syndrome (n = 10) or other forms of functional single-ventricle heart (n = 19). Accessory pulmonary blood flow was included in 18 patients. Preoperative and perioperative data were gathered on retrospective review of patient records, and follow-up was conducted by means of direct physician contact or record review.Results. The overall hospital mortality rate, including that associated with reoperations, was 4.8% (2 of 42 patients). Seven patients (17%) required reoperation related to the BCPS or pulmonary blood flow in the early postoperative period: Procedures included take-down of the BCPS in four patients, with one early death, and procedures to decrease pulmonary blood flow in three patients. Age <1 month correlated significantly with early death and with early failure of the BCPS (death or take-down). Follow-up of the 37 patients discharged with intact BCPS was obtained at a mean ± SD of 14.3 ± 11.3 months postoperatively, during which time three patients died (at 6.5 ± 2.5 months). The 2-year actuarial survival rate for patients undergoing BCPS at <6 months of age was 86%. Overall freedom from death or take-down (including early and late events) was significantly lower in patients <2 months old than in those >2 months old. Four patients have undergone successful Fontan completion (18.3 ± 2.9 months postoperatively), and one patient whose BCPS was taken down subsequently underwent successful restoration of a BCPS.Conclusions. Outcomes after BCPS in young infants are comparable to those in older infants and children. However, our current preference is to defer this procedure until after 2 months of age.(J Am Coll Cardiol 1997;29:1365–70

    Epidemiological studies of pan-azole resistant Aspergillus fumigatus populations sampled during tulip cultivation show clonal expansion with acquisition of multi-fungicide resistance as potential driver

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    Pan-azole resistant isolates are found in clinical and environmental Aspergillus fumigatus (Af) populations. Azole resistance can evolve in both settings, with Af directly targeted by antifungals in patients and, in the environment, Af unintendedly exposed to fungicides used for material preservation and plant disease control. Resistance to non-azole fungi-cides, including methyl benzimidazole carbamates (MBCs), quinone outside inhibitors (QoIs) and succinate dehydrogenase inhibitors (SDHIs), have recently been reported. These fungicide groups are not used in medicine but can play an important role in further spread of pan-azole resistant genotypes. We investigated the multi-fungicide resistance status and genetic diversity of Af populations sampled from tulip field soils, tulip peel waste and flower compost heaps using fungicide sensitivity testing and a range of genotyping tools, including STRAf typing and sequencing of fungicide resistant alleles. Two major clones were present in the tulip bulb population. Comparisons with clinical isolates and literature data revealed that several common clonal lineages of TR34/L98H and TR46/Y121F/T289A strains that have expanded successfully in the environment have also acquired resistance to MBC, QoI and/or SDHI fungicides. Strains carrying multiple fungicide resistant alleles have an advantage in environments where residues of multiple fungicides belonging to different modes of action are presen

    Biomechanics of World-class 800 m women at the 2017 IAAF World Championships

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    The 800 m race challenges the aerobic and anaerobic energy systems, and athletes adopt a technique that allows for running efficiency as well as sprinting speeds. The aim of this novel study was to compare important kinematic variables between the two laps of the 2017 IAAF World Championships women’s final. Video data (150 Hz) were collected of all eight finalists on both laps at a distance approximately 50 m from the finish line along the home straight. Running speed, step length, cadence, temporal variables, sagittal plane joint angles, and shank angle at initial contact were measured. Running speed was faster on lap 2 (p = 0.008) because of large increases in cadence (p = 0.012). These higher cadences resulted in large decreases in contact times (p = 0.031) and in flight times (p = 0.016) on lap 2. Greater knee flexion and ankle plantarflexion (p ≤ 0.039) at initial contact on lap 2 seemed partly responsible for shorter swing times (p = 0.016), and which accompanied a decrease in shank angle at initial contact from lap 1 (7°) to a more vertical position on lap 2 (4°) (p = 0.008). Coaches should note that the need for higher cadence, horizontal impulse production during shorter contact times, and the adoption of forefoot striking require strength and neural system training to allow for athletes to increase cadence during the sprint finish. Increasing cadence (and not step length) was the driving factor for faster finishing speeds in the women’s 800 m
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