SuperWASP observations of pulsating Am stars

We have studied over 1600 Am stars at a photometric precision of 1 mmag with SuperWASP photometric data. Contrary to previous belief, we find that around 200 Am stars are pulsating δ Sct and γ Dor stars, with low amplitudes that have been missed in previous, less extensive studies. While the amplitudes are generally low, the presence of pulsation in Am stars places a strong constraint on atmospheric convection, and may require the pulsation to be laminar. While some pulsating Am stars have been previously found to be δ Sct stars, the vast majority of Am stars known to pulsate are presented in this paper. They will form the basis of future statistical studies of pulsation in the presence of atomic diffusion

Development of procedures for calculating stiffness and damping properties of elastomers in engineering applications. Part 4: Testing of elastomers under a rotating load

A test rig designed to measure stiffness and damping of elastomer cartridges under a rotating load excitation is described. The test rig employs rotating unbalance in a rotor which runs to 60,000 RPM as the excitation mechanism. A variable resonant mass is supported on elastomer elements and the dynamic characteristics are determined from measurements of input and output acceleration. Five different cartridges are considered: three of these are buttons cartridges having buttons located in pairs, with 120 between each pair. Two of the cartridges consist of 360 elastomer rings with rectangular cross-sections. Dynamic stiffness and damping are measured for each cartridge and compared with predictions at different frequencies and different strains

Development of procedures for calculating stiffness and damping of elastomers in engineering applications. Part 5: Elastomer performance limits and the design and test of an elastomer damper

Tests were performed on elastomer specimens of the material polybutadiene to determine the performance limitations imposed by strain, temperature, and frequency. Three specimens were tested: a shear specimen, a compression specimen, and a second compression specimen in which thermocouples were embedded in the elastomer buttons. Stiffness and damping were determined from all tests, and internal temperatures were recorded for the instrumented compression specimen. Measured results are presented together with comparisons between predictions of a thermo-viscoelastic analysis and the measured results. Dampers of polybutadiene and Viton were designed, built, and tested. Vibration measurements were made and sensitivity of vibration to change in unbalance was also determined. Values for log decrement were extracted from the synchronous response curves. Comparisons were made between measured sensitivity to unbalance and log decrement and predicted values for these quantities

“Small steps, or giant leaps?” Comparing game demands of U23, U18, and U16 English academy soccer and their associations with speed and endurance

The current study aimed to compare locomotive outputs across English U16, U18 and U23 academy soccer and investigate possible relationships with neuromuscular and aerobic capacities. Participants included 46 outfield players from an English Category Two soccer academy. Global positioning system (18Hz) data were utilised to analyse locomotive outputs across twenty eleven-a-side matches in each age group. Maximal sprinting speed (MSS) and aerobic speed (MAS) were assessed at the beginning of the season. Absolute total distance (TD), high-speed running (HSR), acceleration and deceleration workloads were higher in U18’s and U23’s vs. U16’s (g = 1.09-2.58; p < 0.05), and absolute sprinting distances were higher in U23’s vs. U16’s (g = 0.96; p < 0.05). In addition, relative HSR outputs were higher in U23’s vs. U18’s (g = 1.84-2.07; p < 0.05). Across the whole cohort, players’ MSS was positively associated with absolute HSR and sprinting distances (ρ = 0.53-0.79; p < 0.05) but not with relative parameters. MAS was positively associated with total distance, decelerations, and both absolute and relative HSR outputs (ρ = 0.33-0.56; p < 0.05). Overall, absolute locomotive outputs were significantly higher in U23’s and U18’s vs. U16’s. Locomotive outputs were also associated with maximal sprinting and aerobic speeds. Thus, training programmes should be tailored to competition demands to optimally prepare each age group for competition and reflect the increasing demands of each level of competition. Further, improving physical fitness (speed and endurance) is likely to drive greater outputs in competition

WASP-1: A lithium- and metal-rich star with an oversized planet

In this paper we present our results of a comprehensive spectroscopicanalysis of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/- 45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high abundance of lithium, log n(Li) = 2.91 +/- 0.05. These parameters suggests an age for the system of 1-3 Gyr and a stellar mass of 1.25-1.35 M_sun. This means that WASP-1 has properties very similar to those of HD 149026, the host star for the highest density planet yet detected. Moreover, their planets orbit at comparable distances and receive comparable irradiating fluxes from their host stars. However, despite the similarity of WASP-1 with HD 149026, their planets have strongly different densities. This suggests that gas-giant planet density is not a simple function of host-star metallicity or of radiation environment at ages of ~2 Gyr.Comment: Accepted for publication in MNRAS. 6 pages, 4 figure

A renormalization group model for the stick-slip behavior of faults

A fault which is treated as an array of asperities with a prescribed statistical distribution of strengths is described. For a linear array the stress is transferred to a single adjacent asperity and for a two dimensional array to three ajacent asperities. It is shown that the solutions bifurcate at a critical applied stress. At stresses less than the critical stress virtually no asperities fail on a large scale and the fault is locked. At the critical stress the solution bifurcates and asperity failure cascades away from the nucleus of failure. It is found that the stick slip behavior of most faults can be attributed to the distribution of asperities on the fault. The observation of stick slip behavior on faults rather than stable sliding, why the observed level of seismicity on a locked fault is very small, and why the stress on a fault is less than that predicted by a standard value of the coefficient of friction are outlined

On the anomaly of Balmer line profiles of A-type stars. Fundamental binary systems

In previous work, Gardiner et al. (1999) found evidence for a discrepancy between the Teff obtained from Balmer lines with that from photometry and fundamental values for A-type stars. An investigation into this anomaly is presented using Balmer line profiles of stars in binary system with fundamental values of both Teff and log g. A revision of the fundamental parameters for binary systems given by Smalley & Dworetsky (1995) is also presented. The Teff obtained by fitting Halpha and Hbeta line profiles is compared to the fundamental values and those obtained from uvby photometry. We find that the discrepancy found by Gardiner et al. (1999) for stars in the range 7000 K < Teff < 9000 K is no longer evident.Comment: 10 pages, 4 figures; Accepted by A&

Purposes, Activities, and Documentation of Early Field Experience in Agricultural Teacher Education: A National Delphi Study

The purpose of this Delphi study was to identify the purpose, expected outcomes, and methods of documenting preservice teacher early field experience (EFE) activities in agricultural teacher education programs. A Delphi technique was used to electronically collect data via email and SurveyMonkey®. An expert panel was established and after three rounds of questioning, the panel identified 16 purpose statements, 14 activities and 9 methods of documenting EFE. The findings of this study, as established by a panel of experts who reached consensus, indicated that EFE should be documented via a combination of journaling and portfolio development. The verification of these documents should be completed by the cooperating teacher and through university assessments. Documentation of an EFE experience can be accomplished through journaling, cooperating teacher signature, reflective paper or a review of collective documents. The results of this study can be used to modify and improve EFE by clarifying the purpose, activities and ways of documented activities in agricultural teacher education programs. This study will aid the profession in providing a more congruent EFE experience for preservice teachers