2,548 research outputs found
The value of non-sport-specific characteristics for talent orientation in young male judo, karate and taekwondo athletes
Background & Study Aim: The present study aims to discriminate young male taekwondo, judo, and karate athletes from two age groups. It is hypothesized that a generic test battery (i.e. consisting of non-sport specific items) can allocate athletes in their respective sports. It is also expected that due to training and experience, differences between sports would be larger in the oldest age group. Material & Methods: Fifty-six highly trained taekwondo, judo, and karate athletes U13 (11.596 ± 0.578 years; n = 30) and U18 (16.097 ± 0.844 years; n = 26) completed five anthropometrical, six physical performance and three motor coordination tests. Discriminant analyses were used to investigate relevant performance measures while MANOVAs were conducted to elucidate the differences between taekwondo, judo and karate. Results: The classification results for both discriminant analyses U13 and U18 showed a perfect classification (100%) of the athletes in their respective sports. U18 showed higher multivariate differences between the three martial arts i.e. for anthropometrical measures (F2.148, P =0.044, ES =0.36), physical performance characteristics (F2.216, P =0.033, ES =0.43) and motor coordination (F6.697, P <0.001, ES =0.49) when compared to their younger counterparts. Judo athletes had the highest scores for sit and reach, handgrip, counter movement jump and balance beam. While taekwondo athletes had the highest scores for sit-ups, sprint 5m and 30m and jumping sideways. Conclusions: Generic talent characteristics allow for a successful discrimination between judo, taekwondo and karate athletes, while the differences between the martial arts profiles are more pronounced in older athletes. © Archives of Budo
Protection of stainless-steels against corrosion in sulphidizing environments by Ce oxide coatings: X-ray absorption and thermogravimetric studies
In this paper a study is reported concerning ceramic coatings containing cerium oxide, prepared by the sol-gel method, used to protect Incoloy 800H against sulphidation. When the coating is sintered in air at 850°C good protection is obtained. In an X-ray absorption spectroscopic study of the coatings it was observed that the best protective coating contains all cerium as CeIV after pretreatment. After sulphidizing cerium was reduced to CeIII. Possible mechanisms to explain the protective properties are discussed
Speciation with gene flow in marine systems
Over the last century, a large body of literature emerged on mechanisms driving speciation. Most of the research into these questions focussed on terrestrial systems, while research in marine systems lagged behind. Here, we review the population genetic mechanisms and geographic context of 33 potential cases of speciation with gene flow in the marine realm, using six criteria inferred from theoretical models of speciation. Speciation with gene flow occurs in a wide range of marine taxa. Single traits, which induce assortative mating and are subjected to disruptive selection, such as differences in host-associations in invertebrates or colour pattern in tropical fish, are potentially responsible for a decrease in gene flow and may be driving divergence in the majority of cases. However, much remains unknown, and with the current knowledge, the frequency of ecological speciation with gene flow in marine systems remains difficult to estimate. Standardized, generally applicable statistical methods, explicitly testing different hypotheses of speciation, are, going forward, required to confidently infer speciation with gene flow
The Yo-Yo intermittent recovery test level 1 is reliable in young high-level soccer players
The aim of the study was to investigate test reliability of the Yo-Yo intermittent recovery test level 1 (YYIR1) in 36 high-level youth soccer players, aged between 13 and 18 years. Players were divided into three age groups (U15, U17 and U19) and completed three YYIR1 in three consecutive weeks. Pairwise comparisons were used to investigate test reliability (for distances and heart rate responses) using technical error (TE), coefficient of variation (CV), intra-class correlation (ICC) and limits of agreement (LOA) with Bland-Altman plots. The mean YYIR1 distances for the U15, U17 and U19 groups were 2024 ± 470 m, 2404 ± 347 m and 2547 ± 337 m, respectively. The results revealed that the TEs varied between 74 and 172 m, CVs between 3.0 and 7.5%, and ICCs between 0.87 and 0.95 across all age groups for the YYIR1 distance. For heart rate responses, the TEs varied between 1 and 6 bpm, CVs between 0.7 and 4.8%, and ICCs between 0.73 and 0.97. The small ratio LOA revealed that any two YYIR1 performances in one week will not differ by more than 9 to 28% due to measurement error. In summary, the YYIR1 performance and the physiological responses have proven to be highly reliable in a sample of Belgian high-level youth soccer players, aged between 13 and 18 years. The demonstrated high level of intermittent endurance capacity in all age groups may be used for comparison of other prospective young soccer players
A longitudinal study investigating the stability of anthropometry and soccerspecific endurance in pubertal high-level youth soccer players
© 2015, Journal of Sports Science and Medicine. All rights reserved. We investigated the evolution and stability of anthropometric and soccer-specific endurance characteristics of 42 high-level, pubertal soccer players with high, average and low yo-yo intermittent recovery test level 1 (YYIR1) baseline performances over two and four years. The rates of improvement were calculated for each performance group, and intra-class correlations were used to verify short- and long-term stability. The main finding was that after two and four years, the magnitudes of the differences at baseline were reduced, although players with high YYIR1 baseline performance still covered the largest distance (e.g., low from 703 m to 2126 m; high from 1503 m to 2434 m over four years). Furthermore, the YYIR1 showed a high stability over two years (ICC = 0.76) and a moderate stability over four years (ICC = 0.59), due to large intra-individual differences in YYIR1 performances over time. Anthropometric measures showed very high stability (ICCs between 0.94 to 0.97) over a two-year period, in comparison with a moderate stability (ICCs between 0.57 and 0.75) over four years. These results confirm the moderate-to-high stability of high-intensity running performance in young soccer players, and suggest that the longer the follow-up, the lower the ability to predict playerâs future potential in running performance. They also show that with growth and maturation, poor performers might only partially catch up their fitter counterparts between 12 and 16 years
Evolution of E2 transition strength in deformed hafnium isotopes from new measurements on Hf, Hf, and Hf
The available data for E2 transition strengths in the region between
neutron-deficient Hf and Pt isotopes are far from complete. More and precise
data are needed to enhance the picture of structure evolution in this region
and to test state-of-the-art nuclear models. In a simple model, the maximum
collectivity is expected at the middle of the major shell. However, for actual
nuclei, this picture may no longer be the case, and one should use a more
realistic nuclear-structure model. We address this point by studying the
spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for
which there is some disagreement in the literature. The main goal is to
measure, for the first time, the half-lives of higher-lying states of the
rotational band. The new results are compared to a theoretical calculation for
absolute transition strengths. The half-lives were measured using \gamma-\gamma
and conversion-electron-\gamma delayed coincidences with the fast timing
method. For the determination of half-lives in the picosecond region, the
generalized centroid difference method was applied. For the theoretical
calculation of the spectroscopic properties, the interacting boson model is
employed, whose Hamiltonian is determined based on microscopic energy-density
functional calculations. The measured 2^+_1 half-lives disagree with results
from earlier \gamma-\gamma fast timing measurements, but are in agreement with
data from Coulomb excitation experiments and other methods. Half-lives of the
4^+_1 and 6^+_1 states were measured, as well as a lower limit for the 8^+_1
states. We show the importance of the mass-dependence of effective boson charge
in the description of E2 transition rates in chains of nuclei. It encourages
further studies of the microscopic origin of this mass dependence. New data on
transition rates in nuclei from neighboring isotopic chains could support these
studies.Comment: 16 pages, 16 figures, 7 tables; Abstract shortened due to character
limi
Shrimps of the genus Periclimenes (Crustacea, Decapoda, Palaemonidae) associated with mushroom corals (Scleractinia, Fungiidae): Linking DNA barcodes to morphology
Most marine palaemonid shrimp species live in symbiosis with invertebrates of various phyla. These associations range from weak epibiosis to obligatory endosymbiosis and from restricted commensalism to semi-parasitism. On coral reefs, such symbiotic shrimps can contribute to the associated biodiversity of reef corals. Among the host taxa, mushroom corals (Cnidaria: Anthozoa: Fungiidae) are known to harbour various groups of symbionts, including shrimps. Some but not all of these associated species are host-specific. Because data on the host specificity of shrimps on mushroom corals are scarce, shrimp species of the genus Periclimenes were collected from mushroom corals during fieldwork in Lembeh Strait, North Sulawesi, Indonesia. Using molecular (COI barcoding gene) and morphological methods, three species of Periclimenes were identified: P. diversipes, P. watamuae and a species new to science, P. subcorallum sp. nov., described herein. Their host specificity was variable, with eight, three and two fungiid host records, respectively. It is concluded that shrimp species of the genus Periclimenes show much overlap in their host choice and that particular morphological traits in the host species appear to play a more important role than phylogenetic affinities within the host group.publishedVersio
Cross-cultural adaptation and validation of the Dutch version of the High Activity Arthroplasty Score
Introduction: The high Activity Arthroplasty Score ( hAAS) has been designed to differentiate in the functional ability between normal and more active patients after total knee arthroplasty (TKA) and total hip arthroplasty (T hA). no such questionnaire is currently available in the Dutch language. The objective of this study was to evaluate the Dutch version of the hAAS in ThA and TKA patients. Patients & Methods: The forward and backward translated Dutch version of the hAAS combined with the national Dutch patient reported outcome measures (PR oMS) were sent to two hundred patients of all ages who underwent TKA or T hA. The internal consistency, construct validity and ceiling/floor effects of the hAAS were evaluated. Results: 108 patients (51 ThA and 57 TKA) participated in this study. A good internal consistency with a Cronbachâs alpha of 0.78, 0.81 and 0.84 was found in all patients, the Th A and the TKA group respectively. Significant positive correla- tions were observed between the hAAS and VAS Qo l, EQ-5D, all K oo S sub-scores except the symptoms score, and all hoo S sub-scores except the Qo l score. A negative correlation was found with the VAS pain. no ceiling or floor effect was seen in the hAAS. Discussion: The Dutch version of the hAAS can be used to evaluate the functional ability in more active patients of all ages who underwent ThA or TKA with an acceptable internal consistency and construct validity, with no ceiling or floor effects
Recent Developments in Speeding up Prostate MRI
The increasing incidence of prostate cancer cases worldwide has led to a tremendous demand for multiparametric MRI (mpMRI). In order to relieve the pressure on healthcare, reducing mpMRI scan time is necessary. This review focuses on recent techniques proposed for faster mpMRI acquisition, specifically shortening T2W and DWI sequences while adhering to the PI-RADS (Prostate Imaging Reporting and Data System) guidelines. Speeding up techniques in the reviewed studies rely on more efficient sampling of data, ranging from the acquisition of fewer averages or b-values to adjustment of the pulse sequence. Novel acquisition methods based on undersampling techniques are often followed by suitable reconstruction methods typically incorporating synthetic priori information. These reconstruction methods often use artificial intelligence for various tasks such as denoising, artifact correction, improvement of image quality, and in the case of DWI, for the generation of synthetic high b-value images or apparent diffusion coefficient maps. Reduction of mpMRI scan time is possible, but it is crucial to maintain diagnostic quality, confirmed through radiological evaluation, to integrate the proposed methods into the standard mpMRI protocol. Additionally, before clinical integration, prospective studies are recommended to validate undersampling techniques to avoid potentially inaccurate results demonstrated by retrospective analysis. This review provides an overview of recently proposed techniques, discussing their implementation, advantages, disadvantages, and diagnostic performance according to PI-RADS guidelines compared to conventional methods. Level of Evidence: 3. Technical Efficacy: Stage 3.</p
- âŠ