4,749 research outputs found
The development of a new sport-specific classification of coping and a meta-analysis of the relationship between different coping strategies and moderators on sporting outcomes
There is an ever growing coping and sports performance literature, with researchers using many different methods to assess performance and different classifications of coping. As such, it makes it difficult to compare studies and therefore identify how coping is related to performance. Furthermore, there are no quantitative syntheses of the results from these studies. A quantitative synthesis would facilitate a more comprehensive understanding of how coping is associated with athletic performance. In order to accurately compare studies, our first aim was to develop a new coping classification that would make this possible. Firstly, we reviewed the strengths and limitations of the different coping classifications and then identified the commonalities and differences between such classifications. We opted for a three-factor classification of coping, because the evidence suggests that a three-factor classification provides a superior model fit to two-factor approaches. Our new classification of coping was based on an existing model from the developmental literature, which received an excellent model fit. We made some adaptations, however, as our classification was intended for an athletic population. As such, we classified coping as mastery (i.e., controlling the situation and eliminating the stressor), internal regulation (i.e., managing internal stress responses), or goal withdrawal (i.e., ceasing efforts towards goal attainment). Undertaking a meta-analysis, our second aim was to identify which coping strategies correlated with sports performance and whether this relationship varied according to moderator variables. Articles were sourced from online electronic databases and manual journal searches. PRISMA guidelines were used to search, select, and synthesize relevant studies. Random effects meta-analyses were performed to identify associations between coping classification and sport performance. Q, I2, and R2 values assessed heterogeneity. Eighteen published investigations, including 3900 participants and incorporating fifty-nine correlations, indicated an overall positive effect for mastery coping, a negligible negative effect for internal regulation coping, and a negative effect for goal withdrawal strategies. The findings of this meta-analysis could be used by sports practitioners to help them deliver effective coping interventions. In order to maximize performance, practitioners could encourage the use of mastery coping, but advise their athletes not to use goal withdrawal strategies
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows
Muskoxen (Ovibos moschatus) are large (\u3e200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2 degrees-5 degrees C above ambient even when air temperature fell to -40 degrees C. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the thermal problems normally associated with a high SA : vol ratio in calves, which reflects the strong selection to conserve energy in winter
Highly accurate and precise infrared transition frequencies of the H3+ cation
Calculation of \textit{ab initio} potential energy surfaces for molecules to high accuracy is only manageable for a handful of molecular systems. Among them is the simplest polyatomic molecule, the \chem{H_3^+} cation. In order to achieve a high degree of accuracy (1 \wn) corrections must be made to the to the traditional Born-Oppenheimer approximation that take into account not only adiabatic and non-adiabatic couplings, but quantum electrodynamic corrections as well. For the lowest rovibrational levels the agreement between theory and experiment is approaching 0.001 \wn, whereas the agreement is on the order of 0.01 â 0.1 \wn for higher levels which are closely rivaling the uncertainties on the experimental data\footnote{L.G. Diniz, J.R. Mohallem, A. Alijah, M. Pavanello, L. Adamowicz, O.L. Polyansky, J. Tennyson \emph{Phys. Rev. A} (2013), \textbf{88}, 032506.}\footnote{O.L. Polyansky, A. Alijah, N.F. Zobov, I.I. Mizus, R.I. Ovsyannikov, J. Tennyson, L. Lodi, T. Szidarovszky, A.G. Cs\'{a}sz\'{a}r \emph{Phil. Trans. R. Soc. A} (2012), \textbf{370}, 5014.}. As method development for calculating these various corrections progresses it becomes necessary for the uncertainties on the experimental data to be improved in order to properly benchmark the calculations.
Previously we have measured 20 rovibrational transitions of \chem{H_3^+} with MHz-level precision, all of which have arisen from low lying rotational levels\footnote{J.N. Hodges, A.J. Perry, P.A. Jenkins II, B.M. Siller, B.J. McCall \emph{J. Chem. Phys.} (2013), \textbf{139}, 164201.}\footnote{A.J. Perry, J.N. Hodges, C.R. Markus, G.S. Kocheril, B.J. McCall \emph{J. Molec. Spectrosc.} (2015), \textbf{317}, 71-73.}. Here we present new measurements of rovibrational transitions arising from higher rotational and vibrational levels. These transitions not only allow for probing higher energies on the potential energy surface, but through the use of combination differences, will ultimately lead to prediction of the âforbiddenâ rotational transitions with MHz-level accuracy
Play-making with migrant farm workers in Ontario, Canada: a kinesthetic and embodied approach to qualitative research
This article is a reflection on the use of theatre creation in qualitative research with migrant farm workers in Ontario, Canada. In this article I examine how the fundamentally embodied and kinesthetic dimensions of seasonal agricultural workersâ lives in Canada highlight the need to seek out and develop corresponding embodied approaches that are able to access and accurately represent the fraught and dynamic nature of workersâ experiences. I bring together ideas from both arts-informed research and participatory action research, and I examine how engaging research participants directly in collective theatre creation can effectively disrupt accepted ways of being and offer an important intervention on worker habitus. I reflect on how through incorporating an element of play-creation in the qualitative research process, I was able to a) access forms of knowledge that may otherwise have remained tacit and b) offer a disruption of the norms of isolation and antagonism endemic to daily life in Canadaâs Seasonal Agricultural Worker Program. This article contributes to debates concerning the role of the arts in qualitative and action research, as well as to those researchers who are seeking innovative ways of designing and implementing qualitative research in the areas of precarious work and citizenshi
Images of work, images of defiance: engaging migrant farm worker voice through community-based arts
This article addresses a stated need within the food justice movement scholarship to increase the attention paid to the political socialization of hired farm hands in industrial agriculture. In Canada, tackling the problem of farm worker equity has particular social and political contours related to the Canadian horticultural industryâs reliance on a state-managed migrant agricultural labour program designed to fill the sectorâs labour market demands. As Canadaâs Seasonal Agricultural Worker Program (SAWP) produces relations of âunfree labourâ, engaging migrant farm workers in social movement initiatives can be particularly challenging. Critical educational interventions designed to encourage migrant farm workersâ contribution to contemporary social movements in Canada must therefore confront the socio-cultural obstacles that constrict migrant farm workersâ opportunities to participate as full members of their communities. In this article, I argue that social justice oriented approaches to community-based arts can provide a means for increasing the social movement contributions of farm workers employed through managed labour migration schema such as Canadaâs SAWP
PROGRESS TOWARDS A HIGH-PRECISION INFRARED SPECTROSCOPIC SURVEY OF THE H3+ ION
The trihydrogen cation, chem{H_3^+}, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, chem{H_3^+} is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculatefootnote{O. Polyansky, textit{et al.}, emph{Phil. Trans. R. Soc. A} (2012), textbf{370}, 5014.}footnote{M. Pavanello, textit{et al.}, emph{J. Chem. Phys.} (2012), textbf{136}, 184303.}footnote{L. Diniz, textit{et al.}, emph{Phys. Rev. A} (2013), textbf{88}, 032506.}footnote{L. Lodi, textit{et al.}, emph{Phys. Rev. A} (2014), textbf{89}, 032505.}. As a result, experimental measurements performed on the chem{H_3^+} ion serve as important benchmarks which are used to test the predictive power of new computational methods.
By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision ( 1 MHz)footnote{J. Hodges, textit{et al.}, emph{J. Chem. Phys} (2013), textbf{139}, 164201.}. Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels
HIGH-RESOLUTION DUAL-COMB SPECTROSCOPY WITH ULTRA-LOW NOISE FREQUENCY COMBS
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Dual-comb spectroscopy is a powerful tool for fast broad-band spectroscopy due to the parallel interrogation of thousands of spectral lines. Here we report on the spectroscopic analysis of acetylene vapor in a pressurized gas cell using two ultra-low noise frequency combs with a repetition rate around 250 MHz. Optical referencing to a high-finesse cavity yields a sub-Hertz stability of all individual comb lines (including the virtual comb lines between 0 Hz and the carrier) and permits one to pick a small difference of repetition rate for the two frequency combs on the order of 300 Hz, thus representing an optical spectrum of 100 THz (3300 wn) within half the free spectral range (125 MHz). The transmission signal is derived straight from a photodetector and recorded with a high-resolution spectrum analyzer or digitized with a computer-controlled AD converter. The figure to the right shows a schematic of the experimental setup which is all fiber-coupled with polarization-maintaining fiber except for the spectroscopic cell. The graph on the lower right reveals a portion of the recorded radio-frequency spectrum which has been scaled to the optical domain. The location of the measured absorption coincides well with data taken from the HITRAN data base. Due to the intrinsic linewidth of all contributing comb lines, each sampling point in the transmission graph corresponds to the probing at an optical frequency with sub-Hertz resolution. This resolution is maintained in coherent wavelength conversion processes such as difference-frequency generation (DFG), sum-frequency generation (SFG) or non-linear broadening (self-phase modulation), and is therefore easily transferred to a wide spectral range from the mid infrared up to the visible spectrum. _x000d
Improving Cavity Enhanced Spectroscopy of Molecular Ions in the Mid-Infrared With Up-Conversion Detection and Brewster-Plate Spoilers
The performance of sensitive spectroscopic methods in the mid-IR is often limited by fringing due to parasitic etalons and the background noise in mid-infrared detectors. In particular, the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS), which is capable of determining the frequencies of strong rovibrational transitions of molecular ions with sub-MHz uncertainty, needs improved sensitivity in order to probe weaker transitions. In this work, we have implemented up-conversion detection with NICE-OHVMS in the 3.2 - 3.9 ÎŒm region to enable the use of faster and more sensitive detectors which cover visible wavelengths. The higher bandwidth enabled detection at optimized heterodyne frequencies, which increased the overall signal from the H43 cation by a factor of three and was able to resolve sub-Doppler features which had previously overlapped. Also, we demonstrate the effectiveness of Brewster-plate spoilers to remove fringes due to parasitic etalons in a cavity enhanced technique. Together, these improvements reduced the instrument\u27s noise equivalent absorption to 5.9 X 10-11 cm-1 Hz-1/2, which represents a factor of 34 improvement in sensitivity compared to previous implementations of NICE-OHVMS. This work will enable extended high-precision spectroscopic surveys of H43 and other important molecular ions
Post-transcriptional regulation of satellite cell quiescence by TTP-mediated mRNA decay.
Skeletal muscle satellite cells in their niche are quiescent and upon muscle injury, exit quiescence, proliferate to repair muscle tissue, and self-renew to replenish the satellite cell population. To understand the mechanisms involved in maintaining satellite cell quiescence, we identified gene transcripts that were differentially expressed during satellite cell activation following muscle injury. Transcripts encoding RNA binding proteins were among the most significantly changed and included the mRNA decay factor Tristetraprolin. Tristetraprolin promotes the decay of MyoD mRNA, which encodes a transcriptional regulator of myogenic commitment, via binding to the MyoD mRNA 3' untranslated region. Upon satellite cell activation, p38α/ÎČ MAPK phosphorylates MAPKAP2 and inactivates Tristetraprolin, stabilizing MyoD mRNA. Satellite cell specific knockdown of Tristetraprolin precociously activates satellite cells in vivo, enabling MyoD accumulation, differentiation and cell fusion into myofibers. Regulation of mRNAs by Tristetraprolin appears to function as one of several critical post-transcriptional regulatory mechanisms controlling satellite cell homeostasis
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