Swimmers' experiences of organizational stress: Exploring the role of cognitive appraisal and coping strategies

This study investigated sport performers’ coping strategies in response to organizational stressors, examined the utility of Skinner, Edge, Altman, and Sherwood’s (2003) categorization of coping within a sport context, determined the short-term perceived effectiveness of the coping strategies used, and explored appraisal-coping associations. Thirteen national standard swimmers completed semi-structured, interval-contingent diaries every day for 28 days. Results revealed 78 coping strategies, which supported 10 of Skinner et al.’s (2003) families of coping. Twenty-four different combinations of coping families were identified. The perceived most effective coping family used in isolation was self-reliance and in combination was escape and negotiation. Stressful appraisals were associated with varied coping strategies. The results highlight the complexity of coping and point to the importance of appraisal-coping associations. Skinner et al.’s (2003) categorization of coping provides a promising conceptual framework for the development of coping research in sport

Curvature and torsion in growing actin networks

Intracellular pathogens such as Listeria monocytogenes and Rickettsia rickettsii move within a host cell by polymerizing a comet-tail of actin fibers that ultimately pushes the cell forward. This dense network of cross-linked actin polymers typically exhibits a striking curvature that causes bacteria to move in gently looping paths. Theoretically, tail curvature has been linked to details of motility by considering force and torque balances from a finite number of polymerizing filaments. Here we track beads coated with a prokaryotic activator of actin polymerization in three dimensions to directly quantify the curvature and torsion of bead motility paths. We find that bead paths are more likely to have low rather than high curvature at any given time. Furthermore, path curvature changes very slowly in time, with an autocorrelation decay time of 200 seconds. Paths with a small radius of curvature, therefore, remain so for an extended period resulting in loops when confined to two dimensions. When allowed to explore a 3D space, path loops are less evident. Finally, we quantify the torsion in the bead paths and show that beads do not exhibit a significant left- or right-handed bias to their motion in 3D. These results suggest that paths of actin-propelled objects may be attributed to slow changes in curvature rather than a fixed torque

Ordinary magic, extraordinary performance: psychological resilience and thriving in high achievers

Although resilience has been referred to as 'ordinary magic' (Masten, 2001, p. 227) that is more common than once thought, the majority of research in this area has sampled individuals who have been required to react to potentially traumatic events outside of their control. The findings of this work, however, are not easily applicable to those who actively seek to engage with challenging situations that present opportunities for them to raise their performance level. The purpose of this study was, therefore, to identify and explore resilient qualities that enable high achievers to thrive and perform at extraordinary levels. Thirteen high achievers (9 male and 4 female) from eleven professions were interviewed in the UK, and interpretative phenomenological analysis was used to identify resilient qualities that enabled the participants to thrive in pressured environments. Results revealed six superordinate themes that characterized resilience and thriving: positive and proactive personality, experience and learning, sense of control, flexibility and adaptability, balance and perspective, and perceived social support. The data highlights the multifaceted nature of resilience comprising a constellation of personal qualities that enable high achievers to excel in demanding contexts. The themes are discussed in relation to previous research findings and in terms of their implications for practicing psychologists. It is anticipated that these themes will provide practitioners with an insight into the distinct features of resilience and thriving in high achievers and help individuals to attain success and well-being in their careers

An Inexpensive Liquid Crystal Spectropolarimeter for the Dominion Astrophysical Observatory Plaskett Telescope

A new, inexpensive polarimetric unit has been constructed for the Dominion Astrophysical Observatory (DAO) 1.8-m Plaskett telescope. It is implemented as a plug-in module for the telescope's existing Cassegrain spectrograph, and enables medium resolution (R~10,000) circular spectropolarimetry of point sources. A dual-beam design together with fast switching of the wave plate at rates up to 100Hz, and synchronized with charge shuffling on the CCD, is used to significantly reduce instrumental effects and achieve high-precision spectropolarimetric measurements for a very low cost. The instrument is optimized to work in the wavelength range 4700 - 5300A to simultaneously detect polarization signals in the H beta line as well as nearby metallic lines. In this paper we describe the technical details of the instrument, our observing strategy and data reduction techniques, and present tests of its scientific performance.Comment: 32 pages, 15 figures. Accepted for publication in PAS

A Bayesian method for detecting stellar flares

We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal model also contains a polynomial background model. This is required to fit underlying light curve variations that are expected in the data, which could otherwise partially mimic a flare. We characterise the false alarm probability and efficiency of this method and compare it with a simpler thresholding method based on that used in Walkowicz et al (2011). We find our method has a significant increase in detection efficiency for low signal-to-noise ratio (S/N) flares. For a conservative false alarm probability our method can detect 95% of flares with S/N less than ~20, as compared to S/N of ~25 for the simpler method. As an example we have applied our method to a selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars with a total of 1873 flares after vetos have been applied. For these flares we have characterised their durations and and signal-to-noise ratios.Comment: Accepted for MNRAS. The code used for the analysis can be found at https://github.com/BayesFlare/bayesflare/releases/tag/v1.0.

Heat transfer between surfaces in contact: An analytical and experimental study of thermal contact resistance of metallic interfaces

Dimensionless correlation for predicting thermal contact resistance between similar metal surfaces in vacuum environmen

A model study of enhanced oil recovery by flooding with aqueous surfactant solution and comparison with theory

With the aim of elucidating the details of enhanced oil recovery by surfactant solution flooding, we have determined the detailed behavior of model systems consisting of a packed column of calcium carbonate particles as the porous rock, n-decane as the trapped oil, and aqueous solutions of the anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The AOT concentration was varied from zero to above the critical aggregation concentration (cac). The salt content of the aqueous solutions was varied to give systems of widely different, post-cac oil–water interfacial tensions. The systems were characterized in detail by measuring the permeability behavior of the packed columns, the adsorption isotherms of AOT from the water to the oil–water interface and to the water–calcium carbonate interface, and oil–water–calcium carbonate contact angles. Measurements of the percent oil recovery by pumping surfactant solutions into calcium carbonate-packed columns initially filled with oil were analyzed in terms of the characterization results. We show that the measured contact angles as a function of AOT concentration are in reasonable agreement with those calculated from values of the surface energy of the calcium carbonate–air surface plus the measured adsorption isotherms. Surfactant adsorption onto the calcium carbonate–water interface causes depletion of its aqueous-phase concentration, and we derive equations which enable the concentration of nonadsorbed surfactant within the packed column to be estimated from measured parameters. The percent oil recovery as a function of the surfactant concentration is determined solely by the oil–water–calcium carbonate contact angle for nonadsorbed surfactant concentrations less than the cac. For surfactant concentrations greater than the cac, additional oil removal occurs by a combination of solubilization and emulsification plus oil mobilization due to the low oil–water interfacial tension and a pumping pressure increase