198 research outputs found
Validity of a Local Positioning System during Outdoor and Indoor Conditions for Team Sports
This study aimed to compare the validity of a local positioning system (LPS) during outdoor and indoor conditions for team sports. The impact of different filtering techniques was also investigated. Five male team sport athletes (age: 27 ± 2 years; maximum oxygen uptake: 48.4 ± 5.1 mL/min/kg) performed 10 trials on a team sport-specific circuit on an artificial turf and in a sports hall. During the circuit, athletes wore two devices of a recent 20-Hz LPS. From the reported raw and differently filtered velocity data, distances covered during different walking, jogging, and sprinting sections within the circuit were computed for which the circuit was equipped with double-light timing gates as criterion measures. The validity was determined by comparing the known and measured distances via the relative typical error of estimate (TEE). The LPS validity for measuring distances covered was good to moderate during both environments (TEE: 0.9â7.1%), whereby the outdoor validity (TEE: 0.9â6.4%) was superior than indoor validity (TEE: 1.2â7.1%). During both environments, validity outcomes of an unknown manufacturer filter were superior (TEE: 0.9â6.2%) compared to those of a standard Butterworth filter (TEE: 0.9â6.4%) and to unprocessed raw data (TEE: 1.0â7.1%). Our findings show that the evaluated LPS can be considered as a good to moderately valid tracking technology to assess running-based movement patterns in team sports during outdoor and indoor conditions. However, outdoor was superior to indoor validity, and also impacted by the applied filtering technique. Our outcomes should be considered for practical purposes like match and training analyses in team sport environments
Selective binding of facial features reveals dynamic expression fragments
The temporal correspondence between two arbitrarily chosen pairs of alternating features can generally be reported for rates up to 3â4âHz. This limit is however surpassed for specialised visual mechanisms that encode conjunctions of features. Here we show that this 3â4âHz limit is exceeded for eye gaze and eyebrow pairing, but not for eye gaze and mouth pairing, suggesting combined eye and eyebrow motion constitutes a dynamic expression fragment; a building block of superordinate facial actions
Migration routes of the Double-wattled Cassowary
This is where the abstract of this record would appear. This is only demonstration data
Sr/Ca ratios in cold-water corals - a âlow-resolutionâ temperature archive?
One of the basic data to understand global change and past global changes is the measurement and the reconstruction of temperature of marine water masses. E.g. seawater temperature controls the density of seawater and in combination with salinity is the major driving force for the oceans circulation system. Geochemical investigations on cold-water corals Lophelia pertusa and Desmophyllum cristagalli indicated the potential of these organisms as high-resolution archives of environmental parameters from intermediate and deeper water masses (Adkins and Boyle 1997). Some studies tried to use cold-water corals as a high-resolution archive of temperature and salinity (Smith et al. 2000, 2002; Blamart et al. 2005; Lutringer et al. 2005). However, the fractionation of stable isotopes (delta18O and delta13C) and element ratios (Sr/Ca, Mg/Ca, U/Ca) are strongly influenced by vital effects (Shirai et al. 2005; Cohen et al. 2006), and difficult to interpret. Nevertheless, ongoing studies indicate the potential of a predominant temperature dependent fractionation of distinct isotopes and elements (e.g. Li/Ca, Montagna et al. 2008; U/Ca, Mg/Ca, delta18O, LĂČpez Correa et al. 2008; delta88/86Sr, RĂŒggeberg et al. 2008).Within the frame of DFG-Project TRISTAN and PalĂ€o-TRISTAN (Du 129/37-2 and 37-3) we investigated live-collected specimens of cold-water coral L. pertusa from all along the European continental margin (Northern and mid Norwegian shelves, Skagerrak, Rockall and Porcupine Bank, Galicia Bank, Gulf of Cadiz, Mediterranean Sea). These coral samples grew in waters characterized by temperatures between 6°C and 14°C. Electron Microprobe investigations along the growth direction of individual coral polyps were applied to determine the relationship between the incorporation of distinct elements (Sr, Ca, Mg, S). Cohen et al. (2006) showed for L.pertusa from the Kosterfjord, Skagerrak, that ~25% of the coralâs Sr/Ca ratio is related to temperature, while 75% are influenced by the calcification rate of the organism. However, the Sr/Ca-temperature relation of our L. pertusa specimens suggest, that mean values are more reliable for temperature reconstruction along a larger temperature range than local high-resolution investigations. Additionally, our results plot on same line of Sr/Ca-temperature relationship like tropical corals indicating a similar behaviour of element incorporation during calcification
Environmental constraints on Holocene coldâwater coral reef growth off Norway: Insights from a multiproxy approach
Expert consensus on the contraindications and cautions of foam rolling: an international delphi study
Background: Foam rolling is a type of self-massage using tools such as foam or roller sticks. However, to date, there is no consensus on contraindications and cautions of foam rolling. A methodological approach to narrow that research gap is to obtain reliable opinions of expert groups. The aim of the study was to develop expertsâ consensus on contraindications and cautions of foam rolling by means of a Delphi process. Methods: An international three-round Delphi study was conducted. Academic experts, defined as having (co-) authored at least one PubMed-listed paper on foam rolling, were invited to participate. Rounds 1 and 2 involved generation and rating of a list of possible contraindications and cautions of foam rolling. In round 3, participants indicated their agreement on contraindications and cautions for a final set of conditions. Consensus was evaluated using a priori defined criteria. Consensus on contraindications and cautions was considered as reached if more than 70% of participating experts labeled the respective item as contraindication and contraindication or caution, respectively, in round 3. Results: In the final Delphi process round, responses were received from 37 participants. Panel participants were predominantly sports scientists ( n = 21), physiotherapists ( n = 6), and medical professionals ( n = 5). Consensus on contraindications was reached for open wounds (73% agreement) and bone fractures (84%). Consensus on cautions was achieved for local tissue inflammation (97%), deep vein thrombosis (97%), osteomyelitis (94%), and myositis ossificans (92%). The highest impact/severity of an adverse event caused by contraindication/cautions was estimated for bone fractures, deep vein thrombosis, and osteomyelitis. Discussion: The mechanical forces applied through foam rolling can be considered as potential threats leading to adverse events in the context of the identified contraindications and cautions. Further evaluations by medical professionals as well as the collection of clinical data are needed to assess the risks of foam rolling and to generate guidance for different applications and professional backgrounds
FACT - Monitoring Blazars at Very High Energies
The First G-APD Cherenkov Telescope (FACT) was built on the Canary Island of
La Palma in October 2011 as a proof of principle for silicon based photosensors
in Cherenkov Astronomy. The scientific goal of the project is to study the
variability of active galatic nuclei (AGN) at TeV energies. Observing a small
sample of TeV blazars whenever possible, an unbiased data sample is collected.
This allows to study the variability of the selected objects on timescales from
hours to years. Results from the first three years of monitoring will be
presented. To provide quick flare alerts to the community and trigger
multi-wavelength observations, a quick look analysis has been installed on-site
providing results publicly online within the same night. In summer 2014,
several flare alerts were issued. Results of the quick look analysis are
summarized.Comment: 2014 Fermi Symposium proceedings - eConf C14102.
Data compression for the First G-APD Cherenkov Telescope
The First Geiger-mode Avalanche photodiode (G-APD) Cherenkov Telescope (FACT)
has been operating on the Canary island of La Palma since October 2011.
Operations were automated so that the system can be operated remotely. Manual
interaction is required only when the observation schedule is modified due to
weather conditions or in case of unexpected events such as a mechanical
failure. Automatic operations enabled high data taking efficiency, which
resulted in up to two terabytes of FITS files being recorded nightly and
transferred from La Palma to the FACT archive at ISDC in Switzerland. Since
long term storage of hundreds of terabytes of observations data is costly, data
compression is mandatory. This paper discusses the design choices that were
made to increase the compression ratio and speed of writing of the data with
respect to existing compression algorithms.
Following a more detailed motivation, the FACT compression algorithm along
with the associated I/O layer is discussed. Eventually, the performances of the
algorithm is compared to other approaches.Comment: 17 pages, accepted to Astronomy and Computing special issue on
astronomical file format
Calibration and performance of the photon sensor response of FACT -- The First G-APD Cherenkov telescope
The First G-APD Cherenkov Telescope (FACT) is the first in-operation test of
the performance of silicon photo detectors in Cherenkov Astronomy. For more
than two years it is operated on La Palma, Canary Islands (Spain), for the
purpose of long-term monitoring of astrophysical sources. For this, the
performance of the photo detectors is crucial and therefore has been studied in
great detail. Special care has been taken for their temperature and voltage
dependence implementing a correction method to keep their properties stable.
Several measurements have been carried out to monitor the performance. The
measurements and their results are shown, demonstrating the stability of the
gain below the percent level. The resulting stability of the whole system is
discussed, nicely demonstrating that silicon photo detectors are perfectly
suited for the usage in Cherenkov telescopes, especially for long-term
monitoring purpose
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