949 research outputs found
ANALYSIS OF ELITE GOLFERS’ KINEMATIC SEQUENCE IN FULL-SWING AND PARTIAL SWING SHOTS
INTRODUCTION: Proximal-to-distal sequencing (PDS) has been observed in full-swing golf shots as in most throwing and striking skills, where the main goal is to maximize speed in the most distal segment of an open-link system (Zheng et al., 2007). Although PDS primarily is associated with mechanical advantage when the speed requirement is high, this temporal order has also been found and ascribed various merits in relatively slow multi-joint movements (Furuya & Kinoshita, 2007). However, no research to date has examined the sequencing pattern in partial golf shots to submaximal distances. The purpose here was to investigate whether PDS is a common characteristic also in partial swing shots of skilled golf players. METHODS: A total of 47 golfers were investigated, 11 male tournament professionals, 23 male amateurs (HCP 0 ± 2 strokes), and 13 female amateurs (HCP -2 ± 2 strokes) performed partial shots with a wedge to targets at three discrete distances (40, 55 and 70 m), and full-swing shots with a five iron as well as a driver in the same direction for maximal distance. Pelvis, upper torso, and hand movement were recorded in 3D with an electromagnetic tracking system (Polhemus) at 240 Hz. The magnitude of the resultant angular velocity vector of each segment was used to examine the sequencing pattern and the angular speed of segment motions. Movement onset, peak amplitude and time for peak amplitude were analyzed in separate repeated-measure ANOVAs with pre-planned Bonferroni corrected pairwise comparisons. Significance level was set at P < 0.05. RESULTS: This study showed a significant proximal-to-distal temporal relationship of movement onset and maximum angular speed at the pelvis, upper torso and hand segments in the golf swing. The same temporal structure was evident in all test conditions, as well as among different genders and levels of expertise. However, the increment in angular speed from the upper torso to hand were significantly larger for male professionals than for female amateurs at all shot conditions and significantly larger for male amateurs than for female amateurs at full-swing shots. DISCUSSION AND CONCLUSION: While there exists a body of evidence in support for PDS providing mechanical advantages when the highest possible ball speed is to be achieved, merits of PDS in partial golf shots are less evident. However, it has been proposed that a given torque or force can be more accurately generated by a stronger muscle than a weaker muscle (Hamilton et al., 2004) and a potential role of the observed sequencing pattern in partial shots of skilled golf players could be to improve accuracy and minimize the speed-accuracy tradeoff. REFERENCES: Zheng N., Barrentine S.W., Fleizig G.S., Andrews J.R. (2008). Kinematic analysis of swing in pro and amateur golfers, International Journal of Sports Medicine, 6, 487-493. Furuya S., Kinoshita H. (2007). Roles of proximal-to-distal sequential organization of the upper limb segments in striking the keys by expert pianists, Neuroscience Letters, 421, 264-269. Hamilton A., Jones K.E., Wolpert D.M. (2004). The scaling of motor noise with muscle strength and motor unit number in humans, Experimental Brain Research, 157, 417-430
Small Band Gap Polymers Synthesized via a Modified Nitration of 4,7-Dibromo-2,1,3-benzothiadiazole
The nitration of 4,7-dibromo-2,1,3-benzothiadiazole was modified by using CF3SO3H and HNO3 as the nitrating agent, and the related yield was improved greatly. On the basis of this improvement, two new small band gap polymers, P1TPQ and P3TPQ, were developed. Bulk heterojunction solar cells based on P3TPO and [6,6]-phenyl-C-71-butyric acid methyl ester exhibit interesting results with a power conversion efficiency of 21% and photoresponse up to 1.1 mu
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Biases in the perceived timing of perisaccadic perceptual and motor events
Subjects typically experience the temporal interval immediately following a saccade as longer than a comparable control interval. One explanation of this effect is that the brain antedates the perceptual onset of a saccade target to around the time of saccade initiation. This could explain the apparent continuity of visual perception across eye movements. Thisantedating account was tested in three experiments in which subjects made saccades of differing extents and then judged either the duration or the temporal order of key events. Postsaccadic stimuli underwent subjective temporal lengthening and had early perceived onsets. A temporally advanced awareness of saccade completion was also found, independently of antedating effects. These results provide convergent evidence supporting antedating and differentiating it from other temporal biases
A Measurement of the Coulomb Dissociation of 8B at 254 MeV/nucleon and the 8B Solar Neutrino Flux
We have measured the Coulomb dissociation of 8B into 7Be and proton at 254
MeV/nucleon using a large-acceptance focusing spectrometer. The astrophysical
S17 factor for the 7Be(p,gamma)8B reaction at E{c.m.} = 0.25-2.78 MeV is
deduced yielding S17(0)=20.6 \pm 1.2 (exp.) \pm 1.0 (theo.) eV-b.
This result agrees with the presently adopted zero-energy S17 factor obtained
in direct-reaction measurements and with the results of other
Coulomb-dissociation studies performed at 46.5 and 51.2 MeV/nucleon.Comment: paper to be published in Phys. Rev. Lett. 3 figures. New Version
fixes formatting problems with the figures only. There are no other change
Intra-specific variation in sensitivity of <i>Bombus terrestris</i> and <i>Osmia bicornis</i> to three pesticides
There is growing evidence that pesticides may be among the causes of worldwide bee declines, which has resulted in repeated calls for their increased scrutiny in regulatory assessments. One recurring concern is that the current frameworks may be biased towards assessing risks to the honey bee. This paradigm requires extrapolating toxicity information across bee species. Most research effort has therefore focused on quantifying differences in sensitivity across species. However, our understanding of how responses to pesticides may vary within a species is still very poor. Here we take the first steps towards filling this knowledge gap by comparing acute, lethal hazards in sexes and castes of the eusocial bee Bombus terrestris and in sexes of the solitary bee Osmia bicornis after oral and contact exposure to the pesticides sulfoxaflor, Amistar (azoxystrobin) and glyphosate. We show that sensitivity towards pesticides varies significantly both within and across species. Bee weight was a meaningful predictor of pesticide susceptibility. However, weight could not fully explain the observed differences, which suggests the existence of unexplored mechanisms regulating pesticide sensitivity across bee sexes and castes. Our data show that intra-specific responses are an overlooked yet important aspect of the risk assessment of pesticides in bees
Quantification of micro-scale variability in fibre bundles
Local variations in the random filament arrangement in carbon fibre bundles were determined by optical microscopy and automated image analysis. Successive steps of abrading, polishing and acquiring micro¬graphs of the sample surface made it feasible to analyse the micro-structure over a series of cross-sections along the fibre bundle path. Random and systematic changes in local filament arrangements were determined. Systematic changes were related to the interaction of a fibre bundle with an intersect¬ing binder thread leading to a local increase of the fibre volume fraction at the interface. Random clus¬tering of filaments in areas of high or low fibre volume fractions within the fibre bundles were found to be unaffected by the relative position of the bundle
Neutron recognition in the LAND detector for large neutron multiplicity
The performance of the LAND neutron detector is studied. Using an
event-mixing technique based on one-neutron data obtained in the S107
experiment at the GSI laboratory, we test the efficiency of various analytic
tools used to determine the multiplicity and kinematic properties of detected
neutrons. A new algorithm developed recently for recognizing neutron showers
from spectator decays in the ALADIN experiment S254 is described in detail. Its
performance is assessed in comparison with other methods. The properties of the
observed neutron events are used to estimate the detection efficiency of LAND
in this experiment.Comment: 16 pages, 8 figure
Isospin dependent multifragmentation of relativistic projectiles
The N/Z dependence of projectile fragmentation at relativistic energies has
been studied with the ALADIN forward spectrometer at the GSI Schwerionen
Synchrotron (SIS). Stable and radioactive Sn and La beams with an incident
energy of 600 MeV per nucleon have been used in order to explore a wide range
of isotopic compositions. For the interpretation of the data, calculations with
the statistical multifragmentation model for a properly chosen ensemble of
excited sources were performed. The parameters of the ensemble, representing
the variety of excited spectator nuclei expected in a participant-spectator
scenario, are determined empirically by searching for an optimum reproduction
of the measured fragment-charge distributions and correlations. An overall very
good agreement is obtained. The possible modification of the liquid-drop
parameters of the fragment description in the hot freeze-out environment is
studied, and a significant reduction of the symmetry-term coefficient is found
necessary to reproduce the mean neutron-to-proton ratios /Z and the
isoscaling parameters of Z<=10 fragments. The calculations are, furthermore,
used to address open questions regarding the modification of the surface-term
coefficient at freeze-out, the N/Z dependence of the nuclear caloric curve, and
the isotopic evolution of the spectator system between its formation during the
initial cascade stage of the reaction and its subsequent breakup.Comment: 23 pages, 29 figures, published in Physical Review
A European Database of Building Energy Profiles to Support the Design of Ground Source Heat Pumps
[EN] The design of ground source heat pumps is a fundamental step to ensure the high energy efficiency of heat pump systems throughout their operating years. To enhance the diffusion of ground source heat pump systems, two different tools are developed in the H2020 research project named, Cheap GSHPs: A design tool and a decision support system. In both cases, the energy demand of the buildings may not be calculated by the user. The main input data, to evaluate the size of the borehole heat exchangers, is the building energy demand. This paper presents a methodology to correlate energy demand, building typologies, and climatic conditions for different types of residential buildings. Rather than envelope properties, three insulation levels have been considered in different climatic conditions to set up a database of energy profiles. Analyzing European climatic test reference years, 23 locations have been considered. For each location, the overall energy and the mean hourly monthly energy profiles for heating and cooling have been calculated. Pre-calculated profiles are needed to size generation systems and, in particular, ground source heat pumps. For this reason, correlations based on the degree days for heating and cooling demand have been found in order to generalize the results for different buildings. These correlations depend on the Koppen-Geiger climate scale.This work received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 657982.Carnieletto, L.; Badenes Badenes, B.; Belliardi, M.; Bernardi, A.; Graci, S.; Emmi, G.; Urchueguía Schölzel, JF.... (2019). A European Database of Building Energy Profiles to Support the Design of Ground Source Heat Pumps. Energies. 12(13):1-23. https://doi.org/10.3390/en12132496S1231213De Carli, M., Tonon, M., Zarrella, A., & Zecchin, R. (2010). A computational capacity resistance model (CaRM) for vertical ground-coupled heat exchangers. Renewable Energy, 35(7), 1537-1550. doi:10.1016/j.renene.2009.11.034Grossi, I., Dongellini, M., Piazzi, A., & Morini, G. L. (2018). Dynamic modelling and energy performance analysis of an innovative dual-source heat pump system. Applied Thermal Engineering, 142, 745-759. doi:10.1016/j.applthermaleng.2018.07.022Engineering Reference Manual. In EnergyPlus V8.5https://energyplus.net/Sandberg, N. H., Bergsdal, H., & Brattebø, H. (2011). Historical energy analysis of the Norwegian dwelling stock. Building Research & Information, 39(1), 1-15. doi:10.1080/09613218.2010.528186Application of Energy Performance Indicators for Residential Building Stocks Experiences of the EPISCOPE Projecthttp://episcope.eu/fileadmin/episcope/public/docs/reports/EPISCOPE_Indicators_ConceptAndExperiences.pdfGustafsson, M., Dipasquale, C., Poppi, S., Bellini, A., Fedrizzi, R., Bales, C., … Holmberg, S. (2017). Economic and environmental analysis of energy renovation packages for European office buildings. Energy and Buildings, 148, 155-165. doi:10.1016/j.enbuild.2017.04.079De Carli, M., Bernardi, A., Cultrera, M., Dalla Santa, G., Di Bella, A., Emmi, G., … Zarrella, A. (2018). A Database for Climatic Conditions around Europe for Promoting GSHP Solutions. Geosciences, 8(2), 71. doi:10.3390/geosciences8020071Cartalis, C., Synodinou, A., Proedrou, M., Tsangrassoulis, A., & Santamouris, M. (2001). Modifications in energy demand in urban areas as a result of climate changes: an assessment for the southeast Mediterranean region. Energy Conversion and Management, 42(14), 1647-1656. doi:10.1016/s0196-8904(00)00156-4Kottek, M., Grieser, J., Beck, C., Rudolf, B., & Rubel, F. (2006). World Map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift, 15(3), 259-263. doi:10.1127/0941-2948/2006/0130Herrera, M., Natarajan, S., Coley, D. A., Kershaw, T., Ramallo-González, A. P., Eames, M., … Wood, M. (2017). A review of current and future weather data for building simulation. Building Services Engineering Research and Technology, 38(5), 602-627. doi:10.1177/0143624417705937Peel, M. C., Finlayson, B. L., & McMahon, T. A. (2007). Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences, 11(5), 1633-1644. doi:10.5194/hess-11-1633-2007D’Amico, A., Ciulla, G., Panno, D., & Ferrari, S. (2019). Building energy demand assessment through heating degree days: The importance of a climatic dataset. Applied Energy, 242, 1285-1306. doi:10.1016/j.apenergy.2019.03.167Al-Hadhrami, L. M. (2013). Comprehensive review of cooling and heating degree days characteristics over Kingdom of Saudi Arabia. Renewable and Sustainable Energy Reviews, 27, 305-314. doi:10.1016/j.rser.2013.04.034Degree Days.net-Custom Degree Day Datahttp://www.degreedays.netAnnunziata, E., Frey, M., & Rizzi, F. (2013). Towards nearly zero-energy buildings: The state-of-art of national regulations in Europe. Energy, 57, 125-133. doi:10.1016/j.energy.2012.11.049Principle for Nearly Zero-Energy Buildings, Ecofys Germany GmbHhttp://bpie.eu/documents/BPIE/publications/LR_nZEB%20study.pdfAhern, C., Griffiths, P., & O’Flaherty, M. (2013). State of the Irish housing stock—Modelling the heat losses of Ireland’s existing detached rural housing stock & estimating the benefit of thermal retrofit measures on this stock. Energy Policy, 55, 139-151. doi:10.1016/j.enpol.2012.11.039Kaklauskas, A., Zavadskas, E. K., Raslanas, S., Ginevicius, R., Komka, A., & Malinauskas, P. (2006). Selection of low-e windows in retrofit of public buildings by applying multiple criteria method COPRAS: A Lithuanian case. Energy and Buildings, 38(5), 454-462. doi:10.1016/j.enbuild.2005.08.005Zavadskas, E., Raslanas, S., & Kaklauskas, A. (2008). The selection of effective retrofit scenarios for panel houses in urban neighborhoods based on expected energy savings and increase in market value: The Vilnius case. Energy and Buildings, 40(4), 573-587. doi:10.1016/j.enbuild.2007.04.015Aerts, D., Minnen, J., Glorieux, I., Wouters, I., & Descamps, F. (2014). A method for the identification and modelling of realistic domestic occupancy sequences for building energy demand simulations and peer comparison. Building and Environment, 75, 67-78. doi:10.1016/j.buildenv.2014.01.021Yang, Z., & Becerik-Gerber, B. (2014). The coupled effects of personalized occupancy profile based HVAC schedules and room reassignment on building energy use. Energy and Buildings, 78, 113-122. doi:10.1016/j.enbuild.2014.04.002Richardson, I., Thomson, M., & Infield, D. (2008). A high-resolution domestic building occupancy model for energy demand simulations. Energy and Buildings, 40(8), 1560-1566. doi:10.1016/j.enbuild.2008.02.006Villi, G., Peretti, C., Graci, S., & De Carli, M. (2013). Building leakage analysis and infiltration modelling for an Italian multi-family building. Journal of Building Performance Simulation, 6(2), 98-118. doi:10.1080/19401493.2012.69998
A falls prevention programme to improve quality of life, physical function and falls efficacy in older people receiving home help services: study protocol for a randomised controlled trial
BACKGROUND:
Falls and fall-related injuries in older adults are associated with great burdens, both for the individuals, the health care system and the society. Previous research has shown evidence for the efficiency of exercise as falls prevention. An understudied group are older adults receiving home help services, and the effect of a falls prevention programme on health-related quality of life is unclear. The primary aim of this randomised controlled trial is to examine the effect of a falls prevention programme on quality of life, physical function and falls efficacy in older adults receiving home help services. A secondary aim is to explore the mediating factors between falls prevention and health-related quality of life.
METHODS:
The study is a single-blinded randomised controlled trial. Participants are older adults, aged 67 or older, receiving home help services, who are able to walk with or without walking aids, who have experienced at least one fall during the last 12 months and who have a Mini Mental State Examination of 23 or above. The intervention group receives a programme, based on the Otago Exercise Programme, lasting 12 weeks including home visits and motivational telephone calls. The control group receives usual care. The primary outcome is health-related quality of life (SF-36). Secondary outcomes are leg strength, balance, walking speed, walking habits, activities of daily living, nutritional status and falls efficacy. All measurements are performed at baseline, following intervention at 3 months and at 6 months' follow-up. Sample size, based on the primary outcome, is set to 150 participants randomised into the two arms, including an estimated 15-20% drop out. Participants are recruited from six municipalities in Norway.
DISCUSSION:
This trial will generate new knowledge on the effects of an exercise falls prevention programme among older fallers receiving home help services. This knowledge will be useful for clinicians, for health managers in the primary health care service and for policy makers
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