5,795 research outputs found
The Geologic Remote Sensing Field Experiment (GRSFE)
Field measurements for the Geologic Remote Sensing Field Experiment (GRSFE) were concentrated in the Lunar Lake area of Nevada. The GRSFE data are meant to be used in a variety of investigations, including tests of multispectral radiative transfer models for scattering and emission from planetary surfaces in support of the Earth Observing System (EOS), Mars Observer, and Magellan Missions. Studies will also be pursued to establish the neotectonic and paleoclimatic history of the arid southwestern United States. The data will also be used to support Mars Rover Sample Return (MRSR) simulation studies
WHY IS THE LEFT KNEE RATHER PRONE TO INJURY DURING TEAM HANDBALL-SPECIFIC SIDE-CUTTING MANEUVERS TO THE RIGHT?
The purpose of this study was the biomechanical inter-leg evaluation in three team handball-specific side-cutting maneuvers. This should help to gain a better understanding how different movement executions potentially produce harmful demands to one or both knee joints. Therefore, eight competitive handball player performed the three most common side-cutting maneuvers to the right side (side-cutting maneuver was performed with alternating or simultaneous steps) in a game-like setting in a movement laboratory. Movement data were collected with a 3D motion capture system and two linked 3D force plates. The analysis of the side-cutting maneuvers revealed increased vertical and medio-lateral ground reaction force components on the left leg, which initiated the side-cutting maneuver. The peak knee abduction moments in the weight acceptance phase did not differ between the left and the right leg in all three side-cutting maneuvers. However, higher peak knee valgus angles occurred at the left leg, which increased with increasing stance time. The results of this study indicate that during the performance of handball-specific side-cutting maneuvers to the right, the left knee joint has a greater risk to get injured. Consequently, athletes and coaches should place special focus on the movement execution of the cutting initiating leg to reduce the risk of knee injuries. Furthermore, leg explosive strength and core stability should be in major focus in training exercises to prepare the athlete for the demands in such high intensity movements
Mixing Time Scale Models for Multiple Mapping Conditioning with Two Reference Variables
A novel multiple mapping conditioning (MMC) approach has been developed for the modelling of turbulent premixed flames including mixture inhomogeneities due to mixture stratification or mixing with the cold surroundings. MMC requires conditioning of a mixing operator on characteristic quantities (reference variables) to ensure localness of mixing in composition space. Previous MMC used the LES-filtered reaction progress variable as reference field. Here, the reference variable space is extended by adding the LES-filtered mixture fraction effectively leading to a double conditioning of the mixing operator. The model is used to predict a turbulent stratified flame and is validated by comparison with experimental data. The introduction of the second reference variable also requires modification of the mixing time scale. Two different mixing time scale models are compared in this work. A novel anisotropic model for stratified combustion leads to somewhat higher levels of fluctuations for the passive scalar when compared with the original model but differences remain small within the flame front. The results show that both models predict flame position and flame structure with good accuracy
Detection of Bulk Motions in the ICM of the Centaurus Cluster
Several recent numerical simulations of off-center cluster mergers predict
that significant angular momentum with associated velocities of a few x 10^{3}
km/s can be imparted to the resulting cluster. Such gas bulk velocities can be
detected by the Doppler shift of X-ray spectral lines with ASCA spectrometers.
Using two ASCA observations of the Centaurus cluster, we produced a velocity
map for the gas in the cluster's central regions. We also detected radial and
azimuthal gradients in temperature and metal abundance distributions, which
seem to be associated with the infalling sub-group centered at NGC 4709 (Cen
45). More importantly, we found a significant (>99.8% confidence level)
velocity gradient along a line near-perpendicular to the direction of the
incoming sub-group and with a maximum velocity difference of ~3.4+-1.1 x 10^{3}
km/s. It is unlikely (P < 0.002) that the observed velocity gradient is
generated by gain fluctuations across the detectors. While the observed
azimuthal temperature and abundance variations can be attributed to the
interaction with Cen 45, we argue that the intracluster gas velocity gradient
is more likely due to a previous off-center merging event in the main body of
the Centaurus cluster.Comment: 13 pages in emulateapj5 style, 8 postscript figures; Accepted by ApJ;
Revised version with minor change
Concussion-reporting behavior in rugby: A national survey of rugby union players in the United States
Background: Rugby is the fastest growing team sport in the United States for male and female athletes. It is a contact/collision sport with an injury risk profile that includes concussions.
Purpose: To examine the prevalence of concussions in male and female rugby players in the United States and to characterize behaviors around reporting concussions that could be a target for prevention and treatment efforts.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: An online survey distributed to active members on the USA Rugby membership list was used to examine self-reported concussions in male and female athletes. Concussion-reporting behaviors and return to play after a concussion were also explored. Statistical analysis was used to compare male with female athletes and report differences, with years of experience as a dependent variable.
Results: The proportion of athletes with a history of at least 1 concussion was 61.9% in all respondents. Of those who reported a concussion, 50.8% reported the concussion during the game or practice in which it occurred, and 57.6% reported at least 1 concussion to a qualified medical provider. Overall, 27.7% of participants who reported ≥1 rugby-related concussion in our survey noted that at least 1 of these concussions was not formally reported. The most commonly cited reasons for not reporting a concussion included not thinking that it was a serious injury, not knowing that it was a concussion at the time, and not wanting to be pulled out of the game or practice. Additionally, 61.0% of athletes did not engage in recommended return-to-play protocols after their most recent rugby-related concussion.
Conclusion: US rugby union athletes may not report concussions to medical personnel or follow return-to-play protocols guided by medical advice. This could result from a lack of education on concussion recognition and the risks associated with continued play after a concussion as well as limited access to health care. Further education efforts focusing on the identification of concussions, removal from play, and return-to-play protocols are necessary in the US rugby union population
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Genome dynamics explain the evolution of flowering time CCT domain gene families in the Poaceae
Numerous CCT domain genes are known to control flowering in plants. They belong to the CONSTANS-like (COL) and PREUDORESPONSE REGULATOR (PRR) gene families, which in addition to a CCT domain possess B-box or response-regulator domains, respectively. Ghd7 is the most recently identified COL gene to have a proven role in the control of flowering time in the Poaceae. However, as it lacks B-box domains, its inclusion within the COL gene family, technically, is incorrect. Here, we show Ghd7 belongs to a larger family of previously uncharacterized Poaceae genes which possess just a single CCT domain, termed here CCT MOTIF FAMILY (CMF) genes. We molecularly describe the CMF (and related COL and PRR) gene families in four sequenced Poaceae species, as well as in the draft genome assembly of barley (Hordeum vulgare). Genetic mapping of the ten barley CMF genes identified, as well as twelve previously unmapped HvCOL and HvPRR genes, finds the majority map to colinear positions relative to their Poaceae orthologues. Combined inter-/intra-species comparative and phylogenetic analysis of CMF, COL and PRR gene families indicates they evolved prior to the monocot/dicot divergence ~200 mya, with Poaceae CMF evolution described as the interplay between whole genome duplication in the ancestral cereal, and subsequent clade-specific mutation, deletion and duplication events. Given the proven role of CMF genes in the modulation of cereals flowering, the molecular, phylogenetic and comparative analysis of the Poaceae CMF, COL and PRR gene families presented here provides the foundation from which functional investigation can be undertaken
A chiral bag model approach to delta electroproduction
Helicity amplitudes for the transition are calculated
using the cloudy bag model. A correction for center-of-mass motion is carried
out using a modified Peierls-Thouless projection method. This reduces the
magnitude of the transition amplitudes at small momentum transfer and enhances
them at modest momentum transfers. Our calculation shows that the pion cloud
contributes substantially to the transition helicity amplitudes, with the final
result giving reasonable agreement with the corresponding experimental values.Comment: 16 pages, 6 ps figures, revte
Genome-wide screening for DNA variants associated with reading and language traits
This research was funded by: Max Planck Society, the University of St Andrews - Grant Number: 018696, US National Institutes of Health - Grant Number: P50 HD027802, Wellcome Trust - Grant Number: 090532/Z/09/Z, and Medical Research Council Hub Grant Grant Number: G0900747 91070Reading and language abilities are heritable traits that are likely to share some genetic influences with each other. To identify pleiotropic genetic variants affecting these traits, we first performed a genome‐wide association scan (GWAS) meta‐analysis using three richly characterized datasets comprising individuals with histories of reading or language problems, and their siblings. GWAS was performed in a total of 1862 participants using the first principal component computed from several quantitative measures of reading‐ and language‐related abilities, both before and after adjustment for performance IQ. We identified novel suggestive associations at the SNPs rs59197085 and rs5995177 (uncorrected P ≈ 10–7 for each SNP), located respectively at the CCDC136/FLNC and RBFOX2 genes. Each of these SNPs then showed evidence for effects across multiple reading and language traits in univariate association testing against the individual traits. FLNC encodes a structural protein involved in cytoskeleton remodelling, while RBFOX2 is an important regulator of alternative splicing in neurons. The CCDC136/FLNC locus showed association with a comparable reading/language measure in an independent sample of 6434 participants from the general population, although involving distinct alleles of the associated SNP. Our datasets will form an important part of on‐going international efforts to identify genes contributing to reading and language skills.Publisher PDFPeer reviewe
Zero-field spin splitting in InAs-AlSb quantum wells revisited
We present magnetotransport experiments on high-quality InAs-AlSb quantum
wells that show a perfectly clean single-period Shubnikov-de Haas oscillation
down to very low magnetic fields. In contrast to theoretical expectations based
on an asymmetry induced zero-field spin splitting, no beating effect is
observed. The carrier density has been changed by the persistent photo
conductivity effect as well as via the application of hydrostatic pressure in
order to influence the electric field at the interface of the electron gas.
Still no indication of spin splitting at zero magnetic field was observed in
spite of highly resolved Shubnikov- de Haas oscillations up to filling factors
of 200. This surprising and unexpected result is discussed in view of other
recently published data.Comment: 4 pages, 3 figures, submitted to Phys. Rev.
An fMRI study
Background Maternal sensitive behavior depends on recognizing one’s own
child’s affective states. The present study investigated distinct and
overlapping neural responses of mothers to sad and happy facial expressions of
their own child (in comparison to facial expressions of an unfamiliar child).
Methods We used functional MRI to measure dissociable and overlapping
activation patterns in 27 healthy mothers in response to happy, neutral and
sad facial expressions of their own school-aged child and a gender- and age-
matched unfamiliar child. To investigate differential activation to sad
compared to happy faces of one’s own child, we used interaction contrasts.
During the scan, mothers had to indicate the affect of the presented face.
After scanning, they were asked to rate the perceived emotional arousal and
valence levels for each face using a 7-point Likert-scale (adapted SAM
version). Results While viewing their own child’s sad faces, mothers showed
activation in the amygdala and anterior cingulate cortex whereas happy facial
expressions of the own child elicited activation in the hippocampus. Conjoint
activation in response to one’s own child happy and sad expressions was found
in the insula and the superior temporal gyrus. Conclusions Maternal brain
activations differed depending on the child’s affective state. Sad faces of
the own child activated areas commonly associated with a threat detection
network, whereas happy faces activated reward related brain areas. Overlapping
activation was found in empathy related networks. These distinct neural
activation patterns might facilitate sensitive maternal behavior
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