The effect of a scanning flat fold mirror on a CMB B-mode experiment

We investigate the possibility of using a flat-fold beam steering mirror for a CMB B-mode experiment. An aluminium flat-fold mirror is found to add $\sim$0.075% polarization, which varies in a scan synchronous way. Time-domain simulations of a realistic scanning pattern are performed, and the effect on the power-spectrum illustrated and a possible method of correction applied.Comment: 8 pages, 5 figures. Accepted for publication in Rev Sci Ins

Hot hands, cold feet? Investigating effects of interacting constraints on place kicking performance at the 2015 Rugby Union World Cup

Place kicks in Rugby Union present valuable opportunities to score points outside the spatiotemporal dynamics of open play but are executed under varying performance constraints. We analysed effects of specific task constraints and relevant contextual factors on place kick performance in the 2015 Rugby Union World Cup. Data were collected from television broadcasts for each place kick. In addition to kick outcomes, contextual factors, including time of the kick in the match, score margin at the time of the kick, and outcome of the kicker’s previous kick, were recorded. Effects of spatial task constraints were analysed for each kick, using distance (m) and angle (°) of the kick to the goalposts. A binomial logistic regression model revealed that distance from, and angle to, the goalposts were significant predictors of place kick outcome. Furthermore, the success percentage of kickers who missed their previous kick was 7% lower than those who scored their previous kick. Place kick success percentage in the 10 minutes before half-time was 8% lower than the mean tournament success percentage, which was 75% (95% CI 71% to 78%). The highest kick success percentage was recorded when scores were level (83%; 95% CI 72% to 91%). Our data highlighted how subtle changes in task constraints and contextual factors can influence performance outcomes in elite performers in international competition. Fluctuations in place kick success suggested that individual constraints, such as thoughts, emotions, and fatigue, induced during competition, could interact with perceptions to influence emergent performance behaviours

Experiential knowledge of elite Rugby Union players on key performance constraints in place kicking

There has been a growing tendency in sport science research to examine the relationship between empirical knowledge developed in scientific experiments and theoretical frameworks and the experiential knowledge of elite performers and practitioners (Jones, Bezodis, & Thompson, 2009; Greenwood, Davids, & Renshaw, 2014; Phillips, Davids, Renshaw, & Portus, 2014). In this study, we investigated the experiential knowledge of elite Rugby Union place kickers to access their understanding of how to satisfy interacting constraints of competitive performance and practice environments. Place kicks in Rugby Union offer opportunities to score points outside the spatiotemporal dynamics of open play, but are typically performed under varying task and contextual constraints within a performance environment. Success percentage of place kicks can fluctuate under specific task and contextual constraints, as shown in a recent analysis of the 2015 Rugby World Cup (Pocock, Bezodis, Davids, & North, under review). For example, success percentage can drop sharply at critical thresholds of distance and angle to the goalposts and can vary depending on time elapsed, score margin and previous kick success. Interestingly, place kicks in the 10 minutes before half time were 8% less successful than the tournament average, and place kickers who had missed their previous kick were 7% less successful than place kickers who had scored their previous kick. It has therefore been speculated that emotions induced during competition can interact with perceptions and action to influence the emergent behaviours of place kickers. To develop greater understanding of how fluctuations in performance data may emerge, we interviewed professional Rugby Union place kickers and sought to explore their experiences of satisfying key interacting constraints on performance. Specifically, we aimed to investigate the key constraints that place kickers perceive to influence their emotions and perceptions of task difficulty. A secondary aim of the interviews was to identify specific details of how place kicking situations are currently practised, and why they are structured in this way. We present here the experiential knowledge of place kickers which includes their perceptions of the key constraints in performance environments and how they currently prepare for place kicks. Our findings highlighted how performance constraints can influence emotions, cognitions and perceptions during place kicking performance and the data indicated how the key constraints identified in this study, combined with the findings of previous quantitative analyses, could be represented in training environments. Initial interviews revealed that place kicking is predominantly practised individually and in isolation from game-based scenarios in training, without any form of pressure or expectation. Examples of pressure that place kickers identified in interviews included expectations of team-mates, performing in front of large crowds and closely-matched scores. This presentation will conclude by discussing how an integration of empirical and experiential knowledge can enrich understanding of sport performance and provide recommendations for coaches when designing practice environments which simulate relevant performance constraints to enhance the adaptive skills of elite and developing athletes in sport

Motivation for males to participate in private middle school and high school choruses

The purpose of this descriptive study was to analyze chorus participation by males in private middle schools and high schools located in central North Carolina. Specifically, the study was designed to determine: (a) the number of males in these choruses, as compared to the number of females, and (b) the primary motivators of males' initial and continued participation. The study included a convenience sample (N = 82) comprised of (a) male students who sang in elective secondary-level choruses in private schools (n = 73) and (b) the directors of these choruses (n = 9). The researcher used two researcher-designed surveys to collect data from participants: (a) the Choral Director Survey (CDS), and (b) the Male Choral Student Survey (MCSS). The CDS was completed by school choral director participants and was used to gather information regarding numbers of male and female students in choruses, confirm the elective nature of chorus classes offered, and determine grade level participation in choruses. The MCSS was completed by male student participants and was used to gather motivational data regarding their decisions to join and remain in chorus. Male and female chorus participation data were analyzed using descriptive statistics. Males' initial chorus participation motivational data were analyzed using a factor analysis statistical procedure, and their continued participation motivational data were analyzed using a principal components analysis statistical procedure and a multiple regression statistical procedure. Two Cronbach's Coefficient Alpha measures of internal consistency were calculated to establish the reliability of Parts One and Two of the MCSS data collection instrument. Part One of the MCSS measured male participant motivation for initial chorus participation (á = .921, óe = 8.961) and Part Two of the MCSS measured chorus continued participation (á = .939, óe = 9.293). Both Part One and Part Two of the MCSS measured with a high level of reliability and an acceptable amount of error. Analysis of the male and female chorus participation data confirmed similar results from other studies. In the 11 private middle and high school elective choruses included in the present study, the number of female students exceeded the number of male students. Males comprised 31% of secondary school chorus students. Analysis of male participants' initial chorus participation motivational data revealed two primary factors that explained approximately 55% of the variance in male participant responses: (a) an enjoyment of music and chorus and (b) an interest in a class that was less difficult and time consuming than other available options. Analysis of the male participants' continued chorus participation motivational data revealed two significant predictors, which the researcher titled (a) social and (b) unique class

Understanding key constraints and practice design in Rugby Union place kicking : experiential knowledge of professional kickers and experienced coaches

Place kicks present valuable opportunities to score points in Rugby Union, which are typically performed under varying constraints in competitive performance environments. Previous quantitative studies suggest these interacting constraints can influence fluctuations in place kick success. To further the understanding of how fluctuations in place kicking success emerge, our aim was twofold: i) to explore and identify the key constraints that professional place kickers and experienced place kicking coaches perceive to influence the difficulty of a place kick and ii) to understand the level to which current place kicking practice environments represent these key constraints experienced in performance environments. Six professional place kickers and six experienced place kicking coaches were interviewed. Using a deductive thematic analysis, 11 key constraints were identified: individual constraints of expectation for success and fatigue, task constraints of angle and distance to goalposts, environmental constraints of wind, weather, pitch, and crowd, and situational constraints of previous kicking performance, time remaining and current score margin. Place kicking is typically practised individually or with a small number of place kickers in isolation from team sessions. Where possible, coaches should be encouraged to include place kicking in simulated game scenarios during practice to represent key constraints from performance environments. Our study demonstrates how experiential knowledge can enrich the understanding of sport performance and inform the design of practice environments which simulate relevant constraints of competitive performance to enhance skill adaptation of athletes

Impact of modulation on CMB B-mode polarization experiments

We investigate the impact of both slow and fast polarization modulation strategies on the science return of upcoming ground-based experiments aimed at measuring the B-mode polarization of the CMB. Using simulations of the Clover experiment, we compare the ability of modulated and un-modulated observations to recover the signature of gravitational waves in the polarized CMB sky in the presence of a number of anticipated systematic effects. The general expectations that fast modulation is helpful in mitigating low-frequency detector noise, and that the additional redundancy in the projection of the instrument's polarization sensitivity directions onto the sky when modulating reduces the impact of instrumental polarization, are borne out by our simulations. Neither low-frequency polarized atmospheric fluctuations nor systematic errors in the polarization sensitivity directions are mitigated by modulation. Additionally, we find no significant reduction in the effect of pointing errors by modulation. For a Clover-like experiment, pointing jitter should be negligible but any systematic mis-calibration of the polarization coordinate reference system results in significant E-B mixing on all angular scales and will require careful control. We also stress the importance of combining data from multiple detectors in order to remove the effects of common-mode systematics (such as 1/f atmospheric noise) on the measured polarization signal. Finally we compare the performance of our simulated experiment with the predicted performance from a Fisher analysis. We find good agreement between the Fisher predictions and the simulations except for the very largest scales where the power spectrum estimator we have used introduces additional variance to the B-mode signal recovered from our simulations.Comment: Replaced with version accepted by MNRAS. Analysis of half-wave plate systematic (differential transmittance) adde

The effect of consistent and varied follow-through practice schedules on learning a table tennis backhand

In table tennis the follow-through action after a shot is an important part of skill execution. In this experiment, we aimed to extend literature around the contextual interference effect by investigating whether the way the follow-through is organised in practice affects learning of the backhand shot in table tennis. Thirty unskilled participants were allocated to blocked-variable practice, random-variable practice or a control-constant group and aimed backhand shots towards a target following ball projection from a machine. Each group completed these shots in a pre-test, a training phase with follow-through manipulations, a post-test, and a retention test. The random-variable group improved their shot accuracy from pre-test to post-test and from pre-test to retention test (both P < 0.01, d = 1.03), whereas neither the blocked-variable nor the control-constant group displayed any change in shot accuracy. Practising the follow-through in a random-variable fashion enhanced learning of the preceding shot compared with blocked-variable practice or no follow-through instructions. The benefits of learning motor skills under conditions of high contextual interference also apply to how follow-through actions are organised. The findings are of value to coaches and suggest that instructions related to the follow-through action should be considered as well as the primary skill itself

Investigation of deltamethrin resistance in salmon lice (Lepeophtheirus salmonis) provides no evidence for roles of mutations in voltage-gated sodium channels

BACKGROUND The pyrethroid deltamethrin is used to treat infestations of farmed salmon by parasitic salmon lice, Lepeophtheirus salmonis (Krøyer). However, the efficacy of deltamethrin for salmon delousing is threatened by resistance development. In terrestrial arthropods, knockdown resistance (kdr) mutations of the voltage‐gated sodium channel (Nav), the molecular target for pyrethroids, can cause deltamethrin resistance. A putative kdr mutation of an L. salmonis sodium channel homologue (LsNav1.3 I936V) has previously been identified. At the same time, deltamethrin resistance of L. salmonis has been shown to be inherited maternally and to be associated with mitochondrial DNA (mtDNA) mutations. The present study assessed potential roles of the above putative kdr mutation as a determinant of deltamethrin resistance in laboratory strains and field populations of L. salmonis. RESULTS The deltamethrin resistant L. salmonis strain IoA‐02 expresses the LsNav1.3 I936V mutation but was susceptible to the non‐ester pyrethroid etofenprox, a compound against which pyrethroid resistant arthropods are usually cross‐resistant if resistance is caused by Nav mutations. In a family derived from a cross between an IoA‐02 male and a drug‐susceptible female lacking the kdr mutation, deltamethrin resistance was not associated with the genotype at the LsNav1.3 locus (p>0.05). Similarly, in Scottish field populations of L. salmonis, LsNav1.3 I936V showed no association with deltamethrin resistance. In contrast, genotypes at the mtDNA loci A14013G and A9030G were significantly associated with deltamethrin resistance (P less than 0.001). CONCLUSION In the studied L. salmonis isolates, deltamethrin resistance was unrelated to the LsNav1.3 I936V mutation, but showed close association with mtDNA mutations

Drinking behaviour and alcohol-related harm amongst older adults: analysis of existing UK datasets.

Older adults experience age-related physiological changes that increase sensitivity and decrease tolerance to alcohol and there are a number of age-related harms such as falls, social isolation and elder abuse, which are compounded by alcohol misuse. Despite this unique vulnerability and the fact that the number of older adults is increasing, the literature on drinking behaviour and alcohol-related harm in older adults is sparse. This article describes a secondary analysis of UK data to address this knowledge gap