Fluidic Momentum Controller

Large angular control moments and torques are developed by controllably circulating a relatively small mass of liquid through small diameter pipes describing a large diameter loop. The loop, by generating and storing angular momentum, can thereby provide efficient cancellation of periodic, non-accumulating, externally induced rotational disturbances. The loop is preferably located on or near the periphery of a structure which is to be stabilized

Auroral vector electric field and particle comparisons. 1: Pre-midnight convection topology

Polar 3 was launched in northern Norway on January 27, 1974. Traversing nearly 3 deg latitude, the rocket crossed over a stable IBC II auroral arc in the positive bay region and continued north to a convection boundary which was identified as the Harang discontinuity. Measurement of the complete electric field vector, of energetic electrons and of the auroral N+2 and OI emissions were used to study the convection topology in the pre-magnetic-midnight region. A strong anticorrelation was observed between the electric field and the precipitating energetic electrons. The inverted V nature of the electron precipitations at the convection boundary, compared with the lack of such structure over the arc which was within the positive bay region, leads to the conclusion that auroral arcs are likely to be associated with inverted V type precipitation only at or poleward of convection boundaries and their eddy structures

Exploring childhood obesity prevention among diverse ethnic groups in schools and places of worship: recruitment, acceptability and feasibility of data collection and intervention components

Small-scale, detailed exploration of the recruitment, assessment, and evaluation processes of obesity intervention among minority ethnic children. The study took place in schools and places of worship during 2008-2010 in London, UK. Measures included 3-day food diaries, 24 hour dietary recalls, the Youth Physical Activity Questionnaire, accelerometry, and diet and physical activity self-efficacy questionnaires. Potential intervention components were evaluated via observation, questionnaires, and focus group discussions. Schools and places of worship that reflected the ethnic and religious diversity of inner city London populations (Hindus, Muslims and Christians) were targeted. Telephone invitations to 12 schools achieved recruitment of five schools (42% response); 181 invitations to 94 places of worship, recruited eight organisations (9%). Multi-strategy approaches were required to build relationships with faith organisations. Sixty-five children aged 8-13 years participated in the testing of measures. High completion rates were achieved for 24 hour recalls, diet and PA self-efficacy questionnaires (ranging from 89% to 100%), with more consistent quality in schools. Dietary assessment highlighted inadequacies in composition data for minority ethnic foods. Intervention sessions were tested among 155 children in all five schools, and 33 children in a church, temple and mosque. Evaluation coverage was more consistent in these places of worship than in schools. Schools may logistically be more straightforward settings for delivery of interventions but, despite complex issues (engagement strategies; cultural foodways), places of worship provide opportunities for effective reach of children, families and communities. We suggest community based participatory research between researchers, schools and community organisations to harness culturally-specific support

Darwinian Selection and Non-existence of Nash Equilibria

We study selection acting on phenotype in a collection of agents playing local games lacking Nash equilibria. After each cycle one of the agents losing most games is replaced by a new agent with new random strategy and game partner. The network generated can be considered critical in the sense that the lifetimes of the agents is power law distributed. The longest surviving agents are those with the lowest absolute score per time step. The emergent ecology is characterized by a broad range of behaviors. Nevertheless, the agents tend to be similar to their opponents in terms of performance.Comment: 4 pages, 5 figure

A solvable model of the evolutionary loop

A model for the evolution of a finite population in a rugged fitness landscape is introduced and solved. The population is trapped in an evolutionary loop, alternating periods of stasis to periods in which it performs adaptive walks. The dependence of the average rarity of the population (a quantity related to the fitness of the most adapted individual) and of the duration of stases on population size and mutation rate is calculated.Comment: 6 pages, EuroLaTeX, 1 figur

Equation of state in 2+1 flavor QCD with improved Wilson quarks by the fixed scale approach

We study the equation of state in 2+1 flavor QCD with nonperturbatively improved Wilson quarks coupled with the RG-improved Iwasaki glue. We apply the $T$-integration method to nonperturbatively calculate the equation of state by the fixed-scale approach. With the fixed-scale approach, we can purely vary the temperature on a line of constant physics without changing the system size and renormalization constants. Unlike the conventional fixed-$N_t$ approach, it is easy to keep scaling violations small at low temperature in the fixed scale approach. We study 2+1 flavor QCD at light quark mass corresponding to $m_\pi/m_\rho \simeq 0.63$, while the strange quark mass is chosen around the physical point. Although the light quark masses are heavier than the physical values yet, our equation of state is roughly consistent with recent results with highly improved staggered quarks at large $N_t$.Comment: 14 pages, 12 figures, v2: Table I and Figure 3 are corrected, reference updated. Main discussions and conclusions are unchanged, v3: version to appear in PRD, v4: reference adde

A Meta-analytic review of the prevalence of neuropathic pain in the general population of the global south compared to the global north

Background It is suspected that the prevalence of Neuropathic pain (NeP) is higher in the countries normally categorized as belonging to the global South, i.e. developing countries, because of the high prevalence of NeP generating diseases including HIV, diabetes mellitus and cancer. However, few articles have estimated the prevalence of NeP in these limited resource countries. By contrast, the prevalence of NeP worldwide has been evaluated in two systematic reviews to range between 3.3% in Austria to 8.2% in the UK (Smith and Torrance, 2012, Hecke et al., 2014) with an outlier of prevalence at 17% in Canada. Aims The aim of this systematic review was to screen the literature for the prevalence of NeP in the general population of the global South and to compare this prevalence with the prevalence in the global North using a meta-analytic approach. Methods Pubmed; Siencedirect; EMBASE; AMED and PsycINFO databases were searched on July 2016 to capture peer reviewed articles that contain data on NeP prevalence either in adult general populations or among chronic pain patients. Two reviewers applied the inclusion criteria and extracted information from all eligible studies including study period, country, study design, sample size, tools to diagnose NeP, outcome and overall prevalence and judged the outcome for each study by scrutinising the methods and result section. Guidelines for reporting Meta-Analysis of Observational Studies in Epidemiology (MOOSE) (Stroup, 2000) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (Moher, 2009) were followed. Random effects modelling was applied on extracted data to produce the overall prevalence in the two study areas. Effect size and confidence intervals of overall prevalences was calculated by producing Forest plots in the Comprehensive Meta-analysis software. Risk of publication bias and heterogeneity between studies were also estimated. Results Out of the 624 studies identified in the search 14 studies were finally selected (total sample size of 78421 patients, 8137 from developing countries (global south) and 70284 from developed countries (global north). The average quality score of all studies was 6.7 out of a maximum of 8. There was a high level of heterogeneity between the studies (I2>90) possibly because of differences in the target populations, sample sizes, study design and data collection methods. However, there was no publication bias as the Egger’s test value was not significant (p=0.053). The prevalence of NeP worldwide was 4.8 % (95%CI, 4.7%-5.0%). Only four studies were conducted in the global South; 2 in Libya, 1 in Morocco and 1 in Brazil. The prevalence of NeP in the global South was 8.3% (7.7%-9.0%). The overall prevalence in the global North was 4.9% (4.7%-6.0%). Conclusion There were few studies on the prevalence of NeP in the global South suggesting that there is less awareness of the significance of NeP in the developing countries. Differences exist between the studies in each region in the estimate of the prevalence of NeP and this is mainly because of differences in data collection methods. Clinical examination tends to produce more variable estimates than telephone, postal and internet based questionnaires using NeP screening tools such as DN4 and S-LANSS. This meta-analysis tentatively suggests that the prevalence of NeP is significantly higher in the global South compared to global North

Queen control of a key life-history event in a eusocial insect

In eusocial insects, inclusive fitness theory predicts potential queen–worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a ‘switch point’ in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen–worker conflicts over colony life history

Lattice QCD with mixed actions

We discuss some of the implications of simulating QCD when the action used for the sea quarks is different from that used for the valence quarks. We present exploratory results for the hadron mass spectrum and pseudoscalar meson decay constants using improved staggered sea quarks and HYP-smeared overlap valence quarks. We propose a method for matching the valence quark mass to the sea quark mass and demonstrate it on UKQCD clover data in the simpler case where the sea and valence actions are the same.Comment: 15 pages, 10 figures some minor modification to text and figures. Accepted for publicatio