272 research outputs found
Global practitioner assessment and management of mental fatigue and mental recovery in high-performance sport : A need for evidence-based best-practice guidelines
Background
Mental fatigue and mental recovery have gained scientific attention in relation to sporting performance, yet best practice assessment and management methods are lacking. A greater understanding of current knowledge and practices in high-performance sport are necessary.
Objective
To understand the contemporary knowledge, beliefs, monitoring processes, management strategies, perceived responsibility, sources of evidence, and challenges, when assessing the mental fatigue and mental recovery of athletes in high-performance sport.
Methods
A mixed-methods survey approach obtained information from 156 multi-disciplinary high-performance sport practitioners. Descriptive outputs were reported and potential differences between key concepts were detected using Wilcoxon-signed rank analysis. Thematic analysis interpreted open-text responses.
Results
Only 11.5% and 5.1% of respondents indicated they were “very” knowledgeable about mental fatigue and mental recovery, respectively. Knowledge (p < 0.001) and confidence in application (p = 0.001) were significantly greater for mental fatigue than mental recovery. Nearly all respondents perceived mental fatigue and mental recovery impacted training and competition performance, with a greater negative impact during competition (p < 0.001). A limited number of respondents reported deliberate assessment (31.1%) or management (51.2%) of mental fatigue and mental recovery. A combination of sources of evidence were used to inform practice, with common challenges to implementation including staff knowledge, athlete-buy in, time-availability, and a lack of evidence. Practitioners reported that assessing and managing mental fatigue and mental recovery was multi-disciplinary in nature.
Conclusion
Practitioners reported that mental fatigue and mental recovery did impact performance, yet this was not reflected in the implementation of evidence-based assessment and management practices in high-performance sport
Scattering of Cosmic Rays by Magnetohydrodynamic Interstellar Turbulence
Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call
for substantial revisions in our understanding of cosmic ray transport. In this
paper we use gyroresonance recently obtained scaling laws for MHD modes to
calculate the scattering frequency for cosmic rays in the ISM. We consider
gyroresonance with MHD modes (Alfvenic, slow and fast) and transit-time damping
(TTD) by fast modes. We conclude that the gyroresonance with fast modes is the
dominant contribution to cosmic ray scattering for the typical interstellar
conditions. In contrast to earlier studies, we find that Alfvenic and slow
modes are inefficient because they are far from isotropy usually assumed.Comment: 4 pages, 2 figures, Phys. Rev. Lett. in press, minor change
Mueller Matrix Parameters for Radio Telescopes and their Observational Determination
Modern digital crosscorrelators permit the simultaneous measurement of all
four Stokes parameters. However, the results must be calibrated to correct for
the polarization transfer function of the receiving system. The transfer
function for any device can be expressed by its Mueller matrix. We express the
matrix elements in terms of fundamental system parameters that describe the
voltage transfer functions (known as the Jones matrix) of the various system
devices in physical terms and thus provide a means for comparing with
engineering calculations and investigating the effects of design changes. We
describe how to determine these parameters with astronomical observations. We
illustrate the method by applying it to some of the receivers at the Arecibo
Observatory.Comment: 23 pages, 2 figures; accepted for PAS
Detection and analysis of new psittacine beak and feather disease virus (PBFDv) nucleotide sequences
ΔΕΝ ΥΠΑΡΧΕΙ ΠΕΡΙΛΗΨΗPsittacine beak and feather disease (PBFD) affects a large number of Psittaciformes species. In this study, five White Cockatoo parrots (Cacatua alba) with clinical signs of PBFD were examined. After euthanasia, a full necropsy of parrots was performed and organs with macroscopic changes were sampled for routine histopathological evaluation. To confirm the presence of psittacine beak and feather disease virus (PBFDv), feather samples were analyzed with the PCR method. Sequence analysis of the obtained PCR products indicated their close relationship (99%) to other PBFDv isolates. Six variable nucleotide sites were discovered, two missense and four silent mutations. This paper presents the evidence of new PBFDv sequence in Cockatoo species
The Large Magellanic Cloud: A power spectral analysis of Spitzer images
We present a power spectral analysis of Spitzer images of the Large
Magellanic Cloud. The power spectra of the FIR emission show two different
power laws. At larger scales (kpc) the slope is ~ -1.6, while at smaller ones
(tens to few hundreds of parsecs) the slope is steeper, with a value ~ -2.9.
The break occurs at a scale around 100-200 pc. We interpret this break as the
scale height of the dust disk of the LMC. We perform high resolution
simulations with and without stellar feedback. Our AMR hydrodynamic simulations
of model galaxies using the LMC mass and rotation curve, confirm that they have
similar two-component power-laws for projected density and that the break does
indeed occur at the disk thickness. Power spectral analysis of velocities
betrays a single power law for in-plane components. The vertical component of
the velocity shows a flat behavior for large structures and a power law similar
to the in-plane velocities at small scales. The motions are highly anisotropic
at large scales, with in-plane velocities being much more important than
vertical ones. In contrast, at small scales, the motions become more isotropic.Comment: 8 pages, 4 figures, talk presented at "Galaxies and their Masks",
celebrating Ken Freeman's 70-th birthday, Sossusvlei, Namibia, April 2010. To
be published by Springer, New York, editors D.L. Block, K.C. Freeman, & I.
Puerar
Discovery of a new Transient X-ray Pulsar in the Small Magellanic Cloud
Rossi X-Ray Timing Explorer observations of the Small Magellanic Cloud have
revealed a previously unknown transient X-ray pulsar with a pulse period of
95s. Provisionally designated XTE SMC95, the pulsar was detected in three
Proportional Counter Array observations during an outburst spanning 4 weeks in
March/April 1999. The pulse profile is double peaked reaching a pulse fraction
\~0.8. The source is proposed as a Be/neutron star system on the basis of its
pulsations, transient nature and characteristically hard X-ray spectrum. The
2-10 keV X-ray luminosity implied by our observations is > 2x10^37 erg/s which
is consistent with that of normal outbursts seen in Galactic systems. This
discovery adds to the emerging picture of the SMC as containing an extremely
dense population of transient high mass X-ray binaries.Comment: Accepted by A&A. 7 pages, 6 figure
A high fat diet induces sex-specific differences in hepatic lipid metabolism and nitrite/nitrate in rats
This work is supported by the grants No.173033 and III41028 from the Ministry of Science, Republic of Serbia.Men and women differ substantially in regard to the severity of insulin resistance (IR) but the underlying mechanism(s) of how this occurs is poorly characterized. We investigated whether a high fat (HF) diet resulted in sex-specific differences in nitrite/nitrate production and lipid metabolism and whether these variances may contribute to altered obesity-induced IR. Male and female Wistar rats were fed a standard laboratory diet or a HF diet for 10 weeks. The level of plasma nitrite/nitrate, as well as free fatty acid (FFA), in both plasma and liver lysates were assessed. The levels of inducible nitric oxide (NO) synthase (iNOS), p65 subunit of NFÎşB, total and phosphorylated forms of Akt, mTOR and PDK-1 in lysates, and the levels of glucose transporter 2 (Glut-2) and fatty acid translocase/cluster of differentiation 36 (FAT/CD36) in plasma membrane fractions of liver were assessed. HF-fed male rats exhibited a significant increase in plasma nitrite/nitrate, and hepatic FFA and FAT/CD36 levels compared with controls. They also displayed a relative decrease in iNOS and Glut-2 levels in the liver. Phosphorylation of Akt (at Ser473 and Thr308), mTOR and PDK-1 was also reduced. HF-fed female rats exhibited increased levels of NFÎşB-p65 in liver compared with controls, while levels of Glut-2, FAT/CD36 and Akt phosphorylation at Thr308 and PDK-1 were decreased. Our results reveal that altered lipid and glucose metabolism in obesity, lead to altered iNOS expression and nitrite/nitrate production. It is likely that this mechanism contributes to sex-specific differences in the development of IR.PostprintPeer reviewe
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