The Towards Silence Project: Multiple String Quartets Organize to Perform a New Musical Form in Spatially Variable and Distributed Conditions

This case describes an example of a collective making process in the field of performing arts. In 2009, multiple string quartets (many considered world class) organized to perform a new musical composition by Sir John Tavener.  The composition challenged four quartets at a time to perform as an integrated ensemble while sitting apart, in various configurations, and at spatial distances up to 70 feet. The process unfolded in three phases: pre-rehearsals of the first group of quartets in the United Kingdom (UK), a series of rehearsals leading to one premiere performance by the second group of quartets in New York, and a series of rehearsals integrated with additional performances in four distinct venues in the UK. Mid-way through the process, the musicians chose to integrate a simple coordinating technology into their process, to address the difficulties produced by distance. This telling of the case story describes what the musicians did to achieve these unprecedented  performances, given the unusual circumstances, emphasizing how they made decisions and evaluated their work along the way. The case is based on comprehensive fieldwork, including observation, interviews, spatial measurement and diagramming, questionnaires, and analysis of videotape of the rehearsal process

What wrist should you wear your actigraphy device on? Analysis of dominant vs. non-dominant wrist actigraphy for measuring sleep in healthy adults

OBJECTIVE: Differences in sleep results due to the placement of actigraphy devices (non-dominant vs. dominant wrist) are yet to be determined. METHODS: 65 nights of data from 13 adult participants was collected while participants wore two actigraphy devices, one on each wrist. Sleep indices including total sleep time (TST), total time in bed (TTB), sleep efficiency (SE%), sleep latency (SL), wake after sleep onset (WASO), sleep onset time (SOT) and wake time (WT) were assessed between the two devices. RESULTS: There were no significant differences between devices for any of the measured sleep variables (p>0.05). SE%, SL and WASO resulted in high correlations between devices (0.89, 0.89 and 0.76, respectively), with all other sleep variables resulting in very high correlations (>0.90) between devices. CONCLUSIONS: Based on our results, it does not seem critical which wrist the actigraphy device is worn on for measuring key sleep variables

Sleeping to perform: examining sleep and exercise in elite female athletes

Sleep plays an essential role in biological functions, and is fundamental for human health and wellbeing. Sleep is also widely recognised as playing an important role in the sporting environment, with an increasing awareness of the importance of sleep in elite athletes. Although sleep research in athletes is increasing, elite athletes are still largely underrepresented in the literature, especially female athletes. Through a series of six studies, this PhD thesis aimed to enhance the understanding of sleep habits of elite athletes, specifically female team sport athletes. The main aim of the thesis was to investigate the sleep habits of elite female team sport athletes in both training and competition environments and also to evaluate interventions to improve sleep and subsequent exercise performance. Study One assessed the reliability and validity of a linear position transducer device as a performance tool for further studies within the thesis. Study Two subjectively and objectively assessed sleep indices in the night leading up to and the nights following competition over a netball season. Study Three investigated perceived and hormonal stress markers and sleep responses following a match, training and control condition. Study Four assessed difference between the melatonin and sleep responses to training and non-training days. Study Fix, objectively assessed the effect of an acute sleep hygiene education session on sleep indices via wrist-actigraphy. Finally, Study Six, an observational and longitudinal study, examined the influence of match-day napping on various performance and perceptual markers. In Study One, a linear position transducer (GymAware, Kinetic Performance Technology, Canberra, Australia), was shown to be a reliable tool for measuring countermovement squat jump performance in female athletes, with a mean intraclass correlation of 0.70 for jump height, 0.90 for peak velocity, and 0.91 for mean velocity. It was also shown to have a Pearson correlation of r = 0.90 and a typical error of ~2.4 cm when compared to a force plate, however the linear position transducer overestimated jump height by an average of 7.0 ± 2.8 cm. In Study Two, 10 elite female athletes completed a survey on their perceived sleep duration and quality on three consecutive nights; the night before the game, the night of the game and the night following the game on 15 separate occasions over a netball season. In addition, on two separate occasions, 11 elite female athlete’s sleep was monitored via an actigraph device for the three consecutive nights. Results showed the athletes perceived sleep duration was significantly different on the night of the game (6:52 h:m) from the night before a game (8:29 h:m). Similarly, when sleep duration was measured using actigraphy, total sleep time was observed to be significantly lower on the night of a game (6:46 h:m) compared to the night before a game (8:31 h:m). Furthermore, total sleep time remained significantly reduced on the night following the game (7:23 h:m). Findings from Study Three provide further support for poor sleep in athletes following evening competition and training. Ten elite female netballers’ sleep was monitored following a netball competition match (MATCH), a netball match simulation session (TRAIN) and a rest day (CON). Salivary cortisol was collected immediately pre and post session, and at 22:00pm. Total sleep time was significantly reduced following the MATCH (6:03 h:m) compared to TRAIN (8:03 h:m) and CON (8:46 h:m). Sleep efficiency was also significantly reduced by 7.7% following the match compared to the training, with sleep latency significantly increased following the game (50.3 minutes) compared to the rest day. Cortisol levels were significantly higher immediately after the match (0.700 μg/dL) compared to training (0.178 μg/dL) and rest (0.077 μg/dL) and remained significantly elevated at 22:00pm. Study Four compared salivary melatonin levels and sleep behavior of 10 elite female athletes between a training session and a control session (rest day). Significant reductions (p < 0.05) in melatonin levels both pre and at 22:00pm were observed in the training condition (6.2 and 17.6 pg/mL, respectively) compared to the control condition (14.8 and 24.3 pg/mL, respectively). The 26 female athletes in Study Five performed one week of baseline sleep monitoring (PRE), followed by a sleep hygiene education session, and a further week of sleep monitoring (POST). Total sleep time significantly increased by 22.3 minutes (p < 0.05), following a one-hour sleep hygiene education session from the PRE week to the POST week. Furthermore, wake variance and wake episode duration were significantly increased from the PRE week to the POST week. Lastly, in Study Six, on each match day, 14 female athletes provided information on their durations of naps and perceived energy levels before performing 3 countermovement jumps 3.5 hours prior to the start of the match on 26 occasions, over two netball seasons. One hour following the match, subjective player performance ratings and coaching staff player performance ratings were obtained. Improved jump performance and ratings of netball performance were observed following nap durations of 20 minutes or less on match-day in elite female athletes, when compared to no nap or naps lasting longer than 20 minutes. In summary, the series of studies in this thesis provides a foundation for understanding sleep in elite female team-sport athletes. Sleep disturbances are prevalent around training and further disturbed around competition environments. These disturbances were also associated with perturbations in different salivary hormones. Furthermore, results show sleep can be acutely improved following a single sleep hygiene education session. And finally, match-day naps of varying duration may have an effect on subsequent match performance, with naps lasting <20 minutes being associated with the most favorable results. The studies provide valuable information on the sleep habits of elite female athletes, which can be used by coaches and practitioners to monitor sleep and establish individualized sleep hygiene protocols. Moreover, the sleep patterns around training and competition should be factored in by practitioners when designing training and recovery programs

The Influence of Match-Day Napping in Elite Female Netball Athletes

Purpose: To assess the effect of match-day napping and duration of naps on perceptual and performance indices in elite female netball players over two consecutive netball seasons. Methods: Fourteen elite female netball athletes (mean ± SD; age = 23 ± 6 yr) participated in an observational study over 26 competition matches. On each match day, athletes provided information on their napping habits, perceived energy levels, and then performed 3 countermovement jumps (CMJ) 3h30 prior to the start of the match. One hour following the match, subjective player performance ratings from the players and two members of the coaching staff were obtained. Naps were characterized into 3 conditions for analysis; No Nap (NN), <20 min Nap (SHORT), and ≥20 min Nap (LONG). Results: A significant difference in peak jump velocity was observed between the SHORT and the NN condition in favor of the shorter nap (3.23 ± 0.26 and 3.07 ± 0.36 m.s-1, respectively, d = 0.34, p < 0.05). A moderate, significant difference (d = 0.85; p < 0.05) was observed for the coach rating of performance (out of 10) between the SHORT and the NN condition (7.2 ± 0.8 and 6.4 ± 0.9, respectively) in favor of SHORT. Conclusion: The findings from the study would suggest that a short nap (<20 min) on the day of competition can enhance jump velocity and improve subjective performance in elite netball players, as assessed by coaching staff

Melatonin and sleep responses following exercise in elite female athletes

To determine the melatonin concentrations and subsequent sleep indices of elite netball athletes following a training day when compared to a control day. Ten elite female netball athletes (mean ± SD; age = 23 ± 6 yrs) provided saliva samples PRE (17:15h) and POST (22:00h) a training session, and a day with no training (CONTROL). Sleep monitoring was performed using wrist actigraphy to assess total time in bed (TTB), total sleep time (TST), sleep efficiency (SE) and sleep latency (SL). Melatonin levels were significantly lower (p < 0.05), both PRE and POST the training condition (6.2 and 17.6 pg/mL, respectively) when compared to the CONTROL (14.8 and 24.3 pg/mL, respectively). There were no significant differences observed between conditions for any of the sleep variables. However, a small reduction in TST could be observed following the training session condition compared to the CONTROL condition. The scheduling of netball training in the evening is shown to suppress salivary melatonin levels. This may have an influence on subsequent sleep following night-time exercise

From pillow to podium: a review on understanding sleep for elite athletes

Sleep is considered vital to human health and well-being, and is critical to physiological and cognitive functioning. Elite athletes experience high training and competition demands, and are often exposed to various factors, situations, and environments that can cause sleep impairments. Previous research has shown that athletes commonly experience sleep loss in the lead up to and following competition, which could have significant impacts on their preparation, performance, and recovery. In particular, the results from previous research show significant reductions in total sleep time (~1:40 h:min) and significant increases in sleep latency (~45 minutes) following evening competition. Napping is common in both the training and competition setting in athletes; however, research on the effect of napping on physiology and performance is limited. In contrast, research on strategies and interventions to improve sleep are increasing in the athletic population, with sleep hygiene research resulting in significant improvements in key sleep indices. This review investigates the physiological importance of sleep in athletes, current tools to monitor athletes’ sleep, the role of sleep for cognitive functioning and athletic performance, the prevalence of sleep disturbances and the potential mechanisms causing sleep disturbances, the role of napping, and different intervention strategies to improve sleep

Amplifier-free slab-coupled optical waveguide optoelectronic oscillator systems.

We demonstrate a free-running 3-GHz slab-coupled optical waveguide (SCOW) optoelectronic oscillator (OEO) with low phase-noise (-120 dBc/Hz at 1-kHz offset) and ultra-low sidemode spurs. These sidemodes are indistinguishable from noise on a spectrum analyzer measurement (88 dB down from carrier). The SCOW-OEO uses high-power low-noise SCOW components in a single-loop cavity employing 1.5-km delay. The noise properties of our SCOW external-cavity laser (SCOWECL) and SCOW photodiode (SCOWPD) are characterized and shown to be suitable for generation of high spectral purity microwave tones. Through comparisons made with SCOW-OEO topologies employing amplification, we observe the sidemode levels to be degraded by any amplifiers (optical or RF) introduced within the OEO cavity

Vanadium oxide monolayer catalysts. I. Preparation, characterization, and thermal stability

Vanadium oxide catalysts of the monolayer type have been prepared by means of chemisorption of vanadate(V)-anions from aqueous solutions and by chemisorption of gaseous V2O3(OH)4. Using Al2O3, Cr2O3, TiO2, CeO2 and ZrO2, catalysts with an approximately complete monomolecular layer of vanadium(V) oxide on the carrier oxides can be prepared, if temperature is not too high. Divalent metal oxides like CdO and ZnO may already form threedimensional surface vanadates at moderate temperature. \ud The thermal stability of a monolayer catalyst is related to the parameter z/a, i. e. the ratio of the carrier cation charge to the sum of ionic radii of carrier cation and oxide anion. Thus, monolayer catalysts will be thermally stable only under the condition that z/a is not too high (aggregated catalyst) nor too small (ternary compound formation)

Low-noise RF-amplifier-free slab-coupled optical waveguide coupled optoelectronic oscillators: physics and operation

We demonstrate a 10-GHz RF-amplifier-free slab-coupled optical waveguide coupled optoelectronic oscillator (SCOW-COEO) system operating with low phase-noise (-115 dBc/Hz at 1 kHz offset) and large sidemode suppression (70 dB measurement-limited). The optical pulses generated by the SCOW-COEO exhibit 26.8-ps pulse width (post compression) with a corresponding spectral bandwidth of 0.25 nm (1.8X transform-limited). We also investigate the mechanisms that limit the performance of the COEO. Our measurements indicate that degradation in the quality factor (Q) of the optical cavity significantly impacts COEO phase-noise through increases in the optical amplifier relative intensity noise (RIN)