Decentralised Learning MACs for Collision-free Access in WLANs

By combining the features of CSMA and TDMA, fully decentralised WLAN MAC schemes have recently been proposed that converge to collision-free schedules. In this paper we describe a MAC with optimal long-run throughput that is almost decentralised. We then design two \changed{schemes} that are practically realisable, decentralised approximations of this optimal scheme and operate with different amounts of sensing information. We achieve this by (1) introducing learning algorithms that can substantially speed up convergence to collision free operation; (2) developing a decentralised schedule length adaptation scheme that provides long-run fair (uniform) access to the medium while maintaining collision-free access for arbitrary numbers of stations

Diet of three large pelagic fishes associated with drifting fish aggregating devices (DFADs) in the western equatorial Indian Ocean

Dieta de tres peces pelágicos de gran tamaño asociados a agregaciones de peces bajo objetos flotantes (DFADs) en el Océano Índico ecuatorial occidental Los objetos flotantes congregan distintas especies de peces en aguas tropicales marinas. Se capturaron tres especies depredadoras: atún de aleta amarilla (Thunnus albacares), petos (Acanthocybium solandri) y llampugas (Coryphaena hippurus) en agregaciones bajo objetos flotantes en el Océano Índico occidental, para caracterizar su dieta y determinar si se alimentan de organismos asociados a las DFADs. Los atunes de aleta amarilla no se alimentaron de presas asociadas a objetos flotantes, mientras los petos y llampugas sí explotaron los recursos agregados a estos objetos flotantes, aunque predominantemente se alimentaron de otros organismos no asociados a ellos. En atunes de aleta amarilla y en llampugas asociados a FADs se observó una predación oportunista en la superficie de agrupaciones de crustáceos estomatópodos pero no así en los petos. Palabras clave: Dispositivos agregadores de peces, Atún de aleta amarilla, Llampuga, Peto, Contenidos estomacales, Dieta.Several species of fish, aggregate around DFADs in marine tropical waters. We captured three predatory species: yellow fin tuna (Thunnus albacares), wahoo (Acanthocybium solandri) and dolphinfish (Coryphaena hippurus) from aggregations under DFADs in the Western Indian Ocean to characterize their diet and determine whether they fed on other DFAD associated organisms. Yellowfin tuna did not feed on DFAD–associated prey, while wahoo and dolphinfish did exploit resources aggregated by the DFADs, though they predominantly fed on other non–associated organisms. Opportunistic feeding on surface swarming stomatopod crustaceans was observed in yellowfin tuna and dolphinfish associated with FADs, but was not observed in wahoo. Key words: FAD, Yellowfin tuna, Dolphinfish, Wahoo, Stomach contents, Diet.Dieta de tres peces pelágicos de gran tamaño asociados a agregaciones de peces bajo objetos flotantes (DFADs) en el Océano Índico ecuatorial occidental Los objetos flotantes congregan distintas especies de peces en aguas tropicales marinas. Se capturaron tres especies depredadoras: atún de aleta amarilla (Thunnus albacares), petos (Acanthocybium solandri) y llampugas (Coryphaena hippurus) en agregaciones bajo objetos flotantes en el Océano Índico occidental, para caracterizar su dieta y determinar si se alimentan de organismos asociados a las DFADs. Los atunes de aleta amarilla no se alimentaron de presas asociadas a objetos flotantes, mientras los petos y llampugas sí explotaron los recursos agregados a estos objetos flotantes, aunque predominantemente se alimentaron de otros organismos no asociados a ellos. En atunes de aleta amarilla y en llampugas asociados a FADs se observó una predación oportunista en la superficie de agrupaciones de crustáceos estomatópodos pero no así en los petos. Palabras clave: Dispositivos agregadores de peces, Atún de aleta amarilla, Llampuga, Peto, Contenidos estomacales, Dieta

The basic chemistry of exercise-induced DNA oxidation:oxidative damage, redox signalling and their interplay

Acute exercise increases reactive oxygen and nitrogen species generation. This phenomenon is associated with two major outcomes: (1) redox signalling and (2) macromolecule damage. Mechanistic knowledge of how exercise-induced redox signalling and macromolecule damage are interlinked is limited. This review focuses on the interplay between exercise-induced redox signalling and DNA damage, using hydroxyl radical (·OH) and hydrogen peroxide (H2O2) as exemplars. It is postulated that the biological fate of H2O2 links the two processes and thus represents a bifurcation point between redox signalling and damage. Indeed, H2O2 can participate in two electron signalling reactions but its diffusion and chemical properties permit DNA oxidation following reaction with transition metals and ·OH generation. It is also considered that the sensing of DNA oxidation by repair proteins constitutes a non-canonical redox signalling mechanism. Further layers of interaction are provided by the redox regulation of DNA repair proteins and their capacity to modulate intracellular H2O2 levels. Overall, exercise-induced redox signalling and DNA damage may be interlinked to a greater extent than was previously thought but this requires further investigation

A realistic evaluation : the case of protocol-based care

Background 'Protocol based care' was envisioned by policy makers as a mechanism for delivering on the service improvement agenda in England. Realistic evaluation is an increasingly popular approach, but few published examples exist, particularly in implementation research. To fill this gap, within this paper we describe the application of a realistic evaluation approach to the study of protocol-based care, whilst sharing findings of relevance about standardising care through the use of protocols, guidelines, and pathways. Methods Situated between positivism and relativism, realistic evaluation is concerned with the identification of underlying causal mechanisms, how they work, and under what conditions. Fundamentally it focuses attention on finding out what works, for whom, how, and in what circumstances. Results In this research, we were interested in understanding the relationships between the type and nature of particular approaches to protocol-based care (mechanisms), within different clinical settings (context), and what impacts this resulted in (outcomes). An evidence review using the principles of realist synthesis resulted in a number of propositions, i.e., context, mechanism, and outcome threads (CMOs). These propositions were then 'tested' through multiple case studies, using multiple methods including non-participant observation, interviews, and document analysis through an iterative analysis process. The initial propositions (conjectured CMOs) only partially corresponded to the findings that emerged during analysis. From the iterative analysis process of scrutinising mechanisms, context, and outcomes we were able to draw out some theoretically generalisable features about what works, for whom, how, and what circumstances in relation to the use of standardised care approaches (refined CMOs). Conclusions As one of the first studies to apply realistic evaluation in implementation research, it was a good fit, particularly given the growing emphasis on understanding how context influences evidence-based practice. The strengths and limitations of the approach are considered, including how to operationalise it and some of the challenges. This approach provided a useful interpretive framework with which to make sense of the multiple factors that were simultaneously at play and being observed through various data sources, and for developing explanatory theory about using standardised care approaches in practice

The Physical and Physiological Demands of Elite International Female Field Hockey Players During Competitive Match-Play.

The aim of the current investigation was to quantify the physical and physiological demands of elite international female field hockey match-play across halves of play. Thirty-eight participants (24 ± 5 years; 173 ± 5 cm; 72 ± 5 kg) took part in nineteen competitive matches during the 2014 - 2015 season. Participants were monitored with GPS technology and heart rate monitors. Players were categorized based on three different playing positions. Activity was categorized into total (m), high-speed running distance (m; >16 km·h) and relative distance (m·min) due to the use of rolling substitutions. Heart rate was classified based on the percentage of players individual HRpeak determined via a Yo-Yo intermittent recovery level 1 test. Players spent on average 44 ± 7 min in match-play. The total distance covered was 5558 ± 527 m (125 ± 23 m·min) with 589 ± 160 m (13 ± 4 m·min) completed at high-speed. Defenders covered a greater total distance compared to other positions of play (p ≤ 0.001). Midfield players covered a greater distance at high-speed (p ≤ 0.001) with the forwards having a higher relative distance (p ≤ 0.001). The HRpeak of the players was 199 ± 1 bmin with a mean exercise intensity of 86 ± 7.8 % of HRpeak. The time spent >85% HRpeak decreased significantly across the halves (p = 0.04, η = 0.09, Small). Defenders were found to spend more time >85 % HRpeak when compared to forwards (p ≤ 0.001). The current investigation provides normative data that coaches should consider when constructing training regimen

Endogenous fantasy and learning in digital games.

Many people believe that educational games are effective because they motivate children to actively engage in a learning activity as part of playing the game. However, seminal work by Malone (1981), exploring the motivational aspects of digital games, concluded that the educational effectiveness of a digital game depends on the way in which learning content is integrated into the fantasy context of the game. In particular, he claimed that content which is intrinsically related to the fantasy will produce better learning than that which is merely extrinsically related. However, this distinction between intrinsic and extrinsic (or endogenous and exogenous) fantasy is a concept that has developed a confused standing over the following years. This paper will address this confusion by providing a review and critique of the empirical and theoretical foundations of endogenous fantasy, and its relevance to creating educational digital games. Substantial concerns are raised about the empirical basis of this work and a theoretical critique of endogenous fantasy is offered, concluding that endogenous fantasy is a misnomer, in so far as the "integral and continuing relationship" of fantasy cannot be justified as a critical means of improving the effectiveness of educational digital games. An alternative perspective on the intrinsic integration of learning content is described, incorporating game mechanics, flow and representations

Nuclear power plant accident simulations of gasket materials under simultaneous radiation plus thermal plus mechanical stress conditions

In order to probe the response of silicone door gasket materials to a postulated severe accident in an Italian nuclear power plant, compression stress relaxation (CSR) and compression set (CS) measurements were conducted under combined radiation (approximately 6 kGy/h) and temperature (up to 230{degrees}C) conditions. By making some reasonable initial assumptions, simplified constant temperature and dose rates were derived that should do a reasonable job of simulating the complex environments for worst-case severe events that combine overall aging plus accidents. Further simplification coupled with thermal-only experiments allowed us to derive thermal-only conditions that can be used to achieve CSR and CS responses similar to those expected from the combined environments that are more difficult to simulate. Although the thermal-only simulations should lead to sealing forces similar to those expected during a severe accident, modulus and density results indicate that significant differences in underlying chemistry are expected for the thermal-only and the combined environment simulations. 15 refs., 31 figs., 15 tabs

Implementing Pharmacy Informatics in College Curricula: The AACP Technology in Pharmacy Education and Learning Special Interest Group

Many professional organizations have initiatives to increase the awareness and use of informatics in the practice of pharmacy. Within education we must respond to these initiatives and make technology integral to all aspects of the curriculum, inculcating in students the importance of technology in practice. This document proposes 5 central domains for organizing planning related to informatics and technology within pharmacy education. The document is intended to encourage discussion of informatics within pharmacy education and the implications of informatics in future pharmacy practice, and to guide colleges of pharmacy in identifying and analyzing informatics topics to be taught and methods of instruction to be used within the doctor of pharmacy curriculum

The Performance Effect of Scheduled Carbohydrate and Caffeine Intake during Simulated Team Sport Match-Play

The aim of the current investigation was to identify the effects of scheduled carbohydrate (CHO) and caffeine (CAF) supplementation on simulated team sport match-play performance. Ten male hurling players completed three hurling match-play simulation protocols (HSP) performed 7 days apart in a double-blind, randomized design. Supplementation included CHO, CHO + CAF, and placebo (PLA). In a randomized order, participants ingested either a 6% CHO solution, a PLA solution of similar taste, or a combined intake of 6% CHO solution + 200 mg CAF capsule. At specific time points (Pre-0 min; half time (HT)-30 min; full time (FT)-60 min), participants completed a repeated sprint protocol (RAST; 12 7 20 m). Physiological [% maximal oxygen uptake (%VO2max), % mean oxygen uptake (%VO2mean), % maximal heart rate (%HRmax), % mean heart rate (%HRmean), respiratory exchange ratio (RER), and blood lactate (BLa)] and performance [(best sprint time (RSAbest), mean sprint time (RSAmean), and rate of perceived exertion (RPE)] variables were monitored throughout each simulation. Non-significant differences were observed between supplement trials (CHO, CHO + CAF, and PLA) for BLa (\u3b72 = 0.001, small), %VO2max (\u3b72 = 0.001, small), %VO2mean (\u3b72 = 0.004, small), %HRmax (\u3b72 = 0.007, small), %HRmean (\u3b72 = 0.018, small), RER (\u3b72 = 0.007, small), RPE (\u3b72 = 0.007, small), and RSAbest (\u3b72 = 0.050, small). RSAmean performance significantly improved in CHO + CAF trials compared to PLA, with sprint times significantly improved from Pre to FT also (\u3b72 = 0.135, medium). A significant difference was observed in BLa between time points (Pre, HT, and FT) (\u3b72 = 0.884, large) in % HRmax (\u3b72 = 0.202, medium), %HRmean (\u3b72 = 0.477, large), and RER (\u3b72 = 0.554, large) across halves and in RPE across time points (\u3b72 = 0.670, large). Our data provide novel data regarding the effects of CHO and CAF supplementation on team sport performance, with co-ingestion of CHO + CAF reducing the decrement in repeated sprint performance compared to PLA

Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

Microdosimetric data indicate that the mean specific energy,zeta, produced by individual charged particles from X rays and gamma rays is different for the two radiation qualities by nearly a factor of two. In order to test whether this influences the initial, linear component in the dose-effect relations, a comparison was made between dose-response curves for pink somatic mutations inTradescantia clone 02 stamen hairs following X and gamma irradiations. Absorbed doses ranged from 2.66 to 300 rad. The results are in agreement with predictions made on the basis of microdosimetric data. At low doses gamma rays are substantially less effective than X rays. The RBE of gamma rays vs. X rays at low doses was approximately 0.6, a value lower than those usually reported in other experimental systems