Trailed vorticity modeling for aeroelastic wind turbine simulations in stand still

Current fast aeroelastic wind turbine codes suitable for certification lack an induction\ud model for standstill conditions. A trailed vorticity model previously used as an addition to a blade element momentum theory based aerodynamic model in normal operation has been extended to allow computing the induced velocities in standstill. The model is validated against analytical results for an elliptical wing in constant inflow and against standstill measurements from the NREL/NASA Phase VI unsteady experiment. The extended model obtains good results in the case of the elliptical wing but underpredicts the steady loading for the Phase VI blade in attached flow. The prediction of the dynamic force coefficient loops from the Phase VI experiment is improved by the trailed vorticity modeling in both attached flow and stall in most cases. The exception is the tangential force coefficient in stall, where the codes and measurements deviate and no clear improvement is visible. This article also contains aeroelastic simulations of the DTU 10 MW reference turbine in standstill at turbulent inflow with a fixed and idling rotor. The influence of the trailed vorticity modeling on the extreme flapwise blade root bending moment is found to be small

Droplet and cluster formation in freely falling granular streams

Particle beams are important tools for probing atomic and molecular interactions. Here we demonstrate that particle beams also offer a unique opportunity to investigate interactions in macroscopic systems, such as granular media. Motivated by recent experiments on streams of grains that exhibit liquid-like breakup into droplets, we use molecular dynamics simulations to investigate the evolution of a dense stream of macroscopic spheres accelerating out of an opening at the bottom of a reservoir. We show how nanoscale details associated with energy dissipation during collisions modify the stream's macroscopic behavior. We find that inelastic collisions collimate the stream, while the presence of short-range attractive interactions drives structure formation. Parameterizing the collision dynamics by the coefficient of restitution (i.e., the ratio of relative velocities before and after impact) and the strength of the cohesive interaction, we map out a spectrum of behaviors that ranges from gas-like jets in which all grains drift apart to liquid-like streams that break into large droplets containing hundreds of grains. We also find a new, intermediate regime in which small aggregates form by capture from the gas phase, similar to what can be observed in molecular beams. Our results show that nearly all aspects of stream behavior are closely related to the velocity gradient associated with vertical free fall. Led by this observation, we propose a simple energy balance model to explain the droplet formation process. The qualitative as well as many quantitative features of the simulations and the model compare well with available experimental data and provide a first quantitative measure of the role of attractions in freely cooling granular streams

Tempo in electronic gaming machines affects behavior among at-risk gamblers

Background and aims: Electronic gaming machines (EGM) may be a particularly addictive form of gambling, and gambling speed is believed to contribute to the addictive potential of such machines. The aim of the current study was to generate more knowledge concerning speed as a structural characteristic in gambling, by comparing the effects of three different bet-to-outcome intervals (BOI) on gamblers bet-sizes, game evaluations and illusion of control during gambling on a computer simulated slot machine. Furthermore, we investigated whether problem gambling moderates effects of BOI on gambling behavior and cognitions. Methods: 62 participants played a computerized slot machine with either fast (400 ms), medium (1700 ms) or slow (3000 ms) BOI. SOGS-R was used to measure pre-existing gambling problems. Mean bet size, game evaluations and illusion of control comprised the dependent variables. Results: Gambling speed had no overall effect on either mean bet size, game evaluations or illusion of control, but in the 400 ms condition, at-risk gamblers (SOGS-R score > 0) employed higher bet sizes compared to no-risk (SOGS-R score = 0) gamblers. Conclusions: The findings corroborate and elaborate on previous studies and indicate that restrictions on gambling speed may serve as a harm reducing effort for at-risk gamblers

Type of musical soundtrack affects behavior in gambling

Abstract Background and aims A long existing notion is that the presence of music might affect gambling behavior. In spite of this, little empirical research on the subject exists. The main aim of the present study was to corroborate and elaborate on the existing findings concerning gambling and music through a laboratory based experiment. Methods A nonclinical sample of 101 undergraduate students (72 females, 29 males) played a computerized gambling task in which either a high-tempo or a low-tempo musical soundtrack was present. Persistence in gambling, reaction time and evaluation of the game comprised the outcome variables. Results Low-tempo music was associated with increased gambling persistence in terms of overall number of bets placed, whereas high-tempo music was associated with intensified gambling in terms of faster reaction time per placed bet. Type of soundtrack was not associated with game evaluation. Discussion Our findings add to the existing knowledge by showing that both low-tempo and high-tempo music can be associated with more risky gambling behavior, the former by increasing gambling persistence and the latter by reducing reaction time for bets placed. Conclusions In sum, the existing studies provide compelling evidence that music can affect various aspects of gambling behavior. These findings may have clinical implications by educating gamblers on the effects of structural mechanisms in gambling on behavior

Problem gambling and the five-factor model of personality: A large population-based study

-Knowledge of the personality characteristics of individuals who develop gambling problems is important for designing targeted prevention efforts. Previous studies of the relationship between the five-factor model of personality and gambling problems were based on small samples not representative of the general population. We estimated differences in Neuroticism, Extroversion, Intellect, Agreeableness and Conscientiousness between non-problem gamblers and individuals with low, moderate and severe gambling problems. Cross-sectional survey Norway 10 081 (51.5% female) individuals aged 16 to 74 years (mean age 46.5 years). The Problem Gambling Severity Index, The Mini-International Personality Item Pool, and demographic variables. Differences between groups of gamblers were analyzed by ordinary least squares regression models separately for each personality trait adjusting for gender, age, cohabitation, level of education and work status. Gamblers with low level, moderate level and severe level of gambling problems differed significantly from non-problem gamblers in Neuroticism (b = 0.16, 0.34 and 0.66 respectively, all p < .001) and Conscientiousness (b = -0.13, -0.27, and -0.44 respectively, all p < .001). Moderate and severe problem gamblers differed from non-problem gamblers in Agreeableness (b = -0.21, p < .001 and b = -0.20, p = .028 respectively). In addition, gambling problems were much more prevalent among men than women, and more prevalent among those who live alone, individuals without tertiary education, and among those who are unemployed or on disability pension. A higher level of problem gambling severity appears to be associated with higher scores on Neuroticism, and with lower scores on Conscientiousness and Agreeableness in the Mini-International Personality Item Pool

Bioinformatics characterization of BcsA-like orphan proteins suggest they form a novel family of pseudomonad cyclic-β-glucan synthases

Bacteria produce a variety of polysaccharides with functional roles in cell surface coating, surface and host interactions, and biofilms. We have identified an ‘Orphan’ bacterial cellulose synthase catalytic subunit (BcsA)-like protein found in four model pseudomonads, P. aeruginosa PA01, P. fluorescens SBW25, P. putida KT2440 and P. syringae pv. tomato DC3000. Pairwise alignments indicated that the Orphan and BcsA proteins shared less than 41% sequence identity suggesting they may not have the same structural folds or function. We identified 112 Orphans among soil and plant-associated pseudomonads as well as in phytopathogenic and human opportunistic pathogenic strains. The wide distribution of these highly conserved proteins suggest they form a novel family of synthases producing a different polysaccharide. In silico analysis, including sequence comparisons, secondary structure and topology predictions, and protein structural modelling, revealed a two-domain transmembrane ovoid-like structure for the Orphan protein with a periplasmic glycosyl hydrolase family GH17 domain linked via a transmembrane region to a cytoplasmic glycosyltransferase family GT2 domain. We suggest the GT2 domain synthesises β-(1,3)-glucan that is transferred to the GH17 domain where it is cleaved and cyclised to produce cyclic-β-(1,3)-glucan (CβG). Our structural models are consistent with enzymatic characterisation and recent molecular simulations of the PaPA01 and PpKT2440 GH17 domains. It also provides a functional explanation linking PaPAK and PaPA14 Orphan (also known as NdvB) transposon mutants with CβG production and biofilm-associated antibiotic resistance. Importantly, cyclic glucans are also involved in osmoregulation, plant infection and induced systemic suppression, and our findings suggest this novel family of CβG synthases may provide similar range of adaptive responses for pseudomonads.<br/

Learning to Run challenge solutions: Adapting reinforcement learning methods for neuromusculoskeletal environments

In the NIPS 2017 Learning to Run challenge, participants were tasked with building a controller for a musculoskeletal model to make it run as fast as possible through an obstacle course. Top participants were invited to describe their algorithms. In this work, we present eight solutions that used deep reinforcement learning approaches, based on algorithms such as Deep Deterministic Policy Gradient, Proximal Policy Optimization, and Trust Region Policy Optimization. Many solutions use similar relaxations and heuristics, such as reward shaping, frame skipping, discretization of the action space, symmetry, and policy blending. However, each of the eight teams implemented different modifications of the known algorithms.Comment: 27 pages, 17 figure

Short Duration Small Sided Football and to a Lesser Extent Whole Body Vibration Exercise Induce Acute Changes in Markers of Bone Turnover.

We aimed to study whether short-duration vibration exercise or football sessions of two different durations acutely changed plasma markers of bone turnover and muscle strain. Inactive premenopausal women (n = 56) were randomized to complete a single bout of short (FG15) or long duration (FG60) small sided football or low magnitude whole body vibration training (VIB). Procollagen type 1 amino-terminal propeptide (P1NP) was increased during exercise for FG15 (51.6 ± 23.0 to 56.5 ± 22.5 μg·L-1, mean ± SD, P 0.05). An increase in osteocalcin was observed 48 h after exercise (P < 0.05), which did not differ between exercise groups. C-terminal telopeptide of type 1 collagen was not affected by exercise. Blood lactate concentration increased during exercise for FG15 (0.6 ± 0.2 to 3.4 ± 1.2 mM) and FG60 (0.6 ± 0.2 to 3.3 ± 2.0 mM), but not for VIB (0.6 ± 0.2 to 0.8 ± 0.4 mM) (P < 0.05). Plasma creatine kinase increased by 55 ± 63% and 137 ± 119% 48 h after FG15 and FG60 (P < 0.05), but not after VIB (26 ± 54%, NS). In contrast to the minor elevation in osteocalcin in response to a single session of vibration exercise, both short and longer durations of small sided football acutely increased plasma P1NP, osteocalcin, and creatine kinase. This may contribute to favorable effects of chronic training on musculoskeletal health

Reference pricing, competition, and pharmaceutical expenditures : theory and evidence from a natural experiment

We study the impact of regulation on competition between brand-names and generics and pharmaceutical expenditures using a unique policy experiment in Norway, where reference pricing (RP) replaced price cap regulation in 2003 for a sub-sample of off-patent products. First, we construct a vertical differentiation model to analyze the impact of regulation on prices and market shares of brand-names and generics. Then, we exploit a detailed panel data set at product level covering several off-patent molecules before and after the policy reform. Off-patent drugs not subject to RP serve as our control group. We find that RP significantly reduces both brand-name and generic prices, and results in significantly lower brand-name market shares. Finally, we show that RP has a strong negative effect on average molecule prices, suggesting significant cost-savings, and that patients’ copayments decrease despite the extra surcharges under RP.Fundação para a Ciência e a Tecnologia (FCT