6,939 research outputs found
A translator writing system for microcomputer high-level languages and assemblers
In order to implement high level languages whenever possible, a translator writing system of advanced design was developed. It is intended for routine production use by many programmers working on different projects. As well as a fairly conventional parser generator, it includes a system for the rapid generation of table driven code generators. The parser generator was developed from a prototype version. The translator writing system includes various tools for the management of the source text of a compiler under construction. In addition, it supplies various default source code sections so that its output is always compilable and executable. The system thereby encourages iterative enhancement as a development methodology by ensuring an executable program from the earliest stages of a compiler development project. The translator writing system includes PASCAL/48 compiler, three assemblers, and two compilers for a subset of HAL/S
Effect of Jump Direction and External Load on Single-Legged Jump-Landing Biomechanics
International Journal of Exercise Science 13(1): 234-248, 2020. External load may increase an individualās risk of non-contact anterior cruciate ligament (ACL) injury during single-legged jump-landing (SLJL).This study evaluated the effects of jump direction and external load on hip and knee joint motion and time to stabilization (TTS) during SLJL. Seventeen active males (n = 8) and females (22.2 Ā± 3.0 y, 1.75 Ā± 0.08 m, 73.4 Ā± 12.0 kg) participated in this randomized, crossover designed study. Single-legged jump-landings performed in two conditions, including without external load (BW) and with a torso-worn weight vest equal to 10% of the participantās body weight (BW+10%), from backward, forward, medial, and lateral SLJL directions. Two-way repeated measures ANOVA did not identify any significant interactions (P \u3e .01, Ī·2: \u3c .001 - .037), but some main effects for condition with small effect sizes were identified (P \u3c .01,Ī·2: .009 - .039). Several main effects for SLJL direction were identified with larger effect sizes (P \u3c .01, Ī·2: .010 - .574). This suggests SLJL direction may challenge different components of SLJL biomechanics, and that recreationally active, college-aged individuals may possess effective compensatory mechanisms that can mitigate the effect of BW+10%
Nested CaseāControl Study of Autoimmune Disease in an Asbestos-Exposed Population
OBJECTIVE: To explore the potential association between asbestos exposure and risk of autoimmune disease, we conducted a caseācontrol study among a cohort of 7,307 current and former residents of Libby, Montana, a community with historical occupational and environmental exposure to asbestos-contaminated vermiculite. METHODS: Cases were defined as those who reported having one of three systemic autoimmune diseases (SAIDs): systemic lupus erythematosus, scleroderma, or rheumatoid arthritis (RA). Controls were randomly selected at a 3:1 ratio from among the remaining 6,813 screening participants using frequency-matched age and sex groupings. RESULTS: The odds ratios (ORs) and 95% confidence intervals (CIs) for SAIDs among those ā„ 65 years of age who had worked for the vermiculite mining company were 2.14 (95% CI, 0.90ā5.10) for all SAIDs and 3.23 (95% CI, 1.31ā7.96) for RA. In this age group, exposure to asbestos while in the military was also an independent risk factor, resulting in a tripling in risk. Other measures of occupational exposure to vermiculite indicated 54% and 65% increased risk for SAIDs and RA, respectively. Those who had reported frequent contact with vermiculite through various exposure pathways also demonstrated elevated risk for SAIDs and RA. We found increasing risk estimates for SAIDs with increasing numbers of reported vermiculite exposure pathways (p < 0.001). CONCLUSION: These preliminary findings support the hypothesis that asbestos exposure is associated with autoimmune disease. Refined measurements of asbestos exposure and SAID status among this cohort will help to further clarify the relationship between these variables
FORCE-VELOCITY PROFILING FOR SHORT ICE HOCKEY SKATING SPRINTS: EFFECT OF EXPONENTIAL FUNCTION
A high-speed digital video camera can be used to obtain highly reliable short-sprint split times. Split time data can be used to estimate instantaneous position, velocity, and acceleration by fitting an exponential function to the known positional data yielding force-velocity (F-V) profiles that may provide more information than just sprint times alone. The purpose of this study was to evaluate the between-rater reliability of different exponential functions used to estimate instantaneous data. A high-speed digital video camera was used to obtain split times from eleven male high-school ice hockey players performing a 6.10 m sprint and a separate top speed test. Including an optimization parameter and using a playerās measured maximal horizontal velocity instead of estimating it tended to produce better between-rater reliability
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Oxidative instability of ionomers in hydroxide-exchange-membrane water electrolyzers
Hydroxide-exchange membrane (HEM) electrolyzers can produce green H2 with only earth-abundant catalysts and electrolyte-free (nominally pure) water feed, significantly decreasing system cost and complexity. However, HEM technology suffers from short lifetimes, attributed in part to poor stability of anion-exchange polymers used in the membrane and catalyst layers. We use electrochemical analysis and ex situ characterization techniques to study anion-exchange-polymer degradation in electrolyzers. Using multiple ionomers, catalyst-layer additives, and electrolyte feed, we show how anode-ionomer oxidation is the dominant degradation mechanism for all HEM-based electrolyzer cells tested. We find improved device stability using oxidation-resistant catalyst-layer binders and propose new design strategies for advanced ionomer and catalyst-layer development
A Comparison of 1978 and 2006 Peak Pollen Seasons and Sampling Methods in Missoula, Montana
A study was conducted in Missoula, Montana to compare local pollen counts from 1978 with those measured nearly 30 years later in 2006 using two different measurement techniques (Durham gravimetric sampler and a Burkard volumetric sampler). Trends in peak pollen times measured during the spring, summer and autumn, respectively, were compared between the two years by Pearsonās correlation and frequency of occurrence of plant genus. Meteorological conditions were also examined during each of the two study periods.
In comparing the two years, there was a statistically significant linear association between the different counts for the months of April through August, with similar levels of pollen types for any given month. The five predominant pollen types (based on counts) identified in each study were Pinus, Poaceae, Populus, Alnus, and Betula for 2006 and Pinus, Poaceae, Populus, Acer and Artemisia for 1978. In summary most of the genera displayed similar peak pollination timing between the two years, suggesting that results from the Durham (gravimetric) and Burkard (volumetric) sampling methods are comparable when reporting relative frequency of occurrence
Community Woodstove Changeout and Impact on Ambient Concentrations of Polycyclic Aromatic Hydrocarbons and Phenolics
A large woodstove changeout program was carried out in Libby, Montana, with the goal of reducing ambient levels of PM2.5. This provided researchers the opportunity to measure ambient concentrations of phenolic and polycyclic aromatic hydrocarbons (PAHs) before, during, and after the changeout of nearly 1200 stoves to evaluate the effectiveness of the intervention. Starting in the heating season of 2004/2005 and ending in the heating season of 2007/2008, 19 compounds were measured every three days using a high-volume polyurethane foam (PUF) sampler followed by gas chromatography and mass spectrometry analysis. Some of the organic species with the highest measured concentrations were also signature chemical markers for wood combustion. When comparing the measurements conducted during the heating season of 2004/2005 (prechangeout) to those of the heating season of 2007/2008 (postchangeout), there was a 64% average reduction in the measured concentrations of phenolics and PAHs, while the PM2.5 mass dropped by only 20% over the same time period. The results of this four year sampling program suggest that the Libby woodstove changeout program was successful in reducing overall concentrations of the measured phenolic and PAH compounds
Enzymatic conformational fluctuations along the reaction coordinate of cytidine deaminase
Analysis of the crystal structures for cytidine deaminase complexed with substrate analog 3-deazacytidine, transition-state analog zebularine 3,4-hydrate, and product uridine establishes significant changes in the magnitude of atomic-scale fluctuations along the (approximate) reaction coordinate of this enzyme. Differences in fluctuations between the substrate analog complex, transition-state analog complex, and product complex are monitored via changes in corresponding crystallographic temperature factors. Previously, we reported that active-site conformational disorder is substantially reduced in the transition-state complex relative to the two ground-state complexes. Here, this result is statistically corroborated by crystallographic data for fluorinated zebularine 3,4-hydrate, a second transition-state analog, and by multiple regression analysis. Multiple regression explains 70% of the total temperature factor variation through a predictive model for the average B-value of an amino acid as a function of the catalytic state of the enzyme (substrate, transition state, product) and five other physical and structural descriptors. Furthermore, correlations of atomic fluctuation magnitudes throughout the body of each complex are quantified through an auto-correlation function. The transition-state analog complex shows the greatest correlations between temperature factor magnitudes for spatially separated atoms, underscoring the strong ability of this reaction-coordinate species to "organize" enzymatic fluctuations. The catalytic significance for decreased atomic-scale motions in the transition state is discussed. A thermodynamic argument indicates that the significant decreases in local enzymatic conformational entropy at the transition state result in enhanced energetic stabilization there
Randomized Trial of Interventions to Improve Childhood Asthma in Homes with Wood-Burning Stoves
BACKGROUND: Household air pollution due to biomass combustion for residential heating adversely affects vulnerable populations. Randomized controlled trials to improve indoor air quality in homes of children with asthma are limited, and no such studies have been conducted in homes using wood for heating.
OBJECTIVES: Our aims were to test the hypothesis that household-level interventions, specifically improved-technology wood-burning appliances or air-filtration devices, would improve health measures, in particular Pediatric Asthma Quality of Life Questionnaire (PAQLQ) scores, relative to placebo, among children living with asthma in homes with wood-burning stoves.
METHODS: A three-arm placebo-controlled randomized trial was conducted in homes with wood-burning stoves among children with asthma. Multiple preintervention and postintervention data included PAQLQ (primary outcome), peak expiratory flow (PEF) monitoring, diurnal peak flow variability (dPFV, an indicator of airway hyperreactivity) and indoor particulate matter (PM) PM2.5.
RESULTS: Relative to placebo, neither the air filter nor the woodstove intervention showed improvement in quality-of-life measures. Among the secondary outcomes, dPFV showed a 4.1 percentage point decrease in variability [95%āconfidenceāintervalā(CI) = ā7.8 to ā0.4] for air-filtration use in comparison with placebo. The air-filter intervention showed a 67% (95% CI: 50% to 77%) reduction in indoor PM2.5, but no change was observed with the improved-technology woodstove intervention.
CONCLUSIONS: Among children with asthma and chronic exposure to woodsmoke, an air-filter intervention that improved indoor air quality did not affect quality-of-life measures. Intent-to-treat analysis did show an improvement in the secondary measure of dPFV
Women and Illegal Activities: Gender Differences and Women's Willingness to Comply Over Time
In recent years the topics of illegal activities such as corruption or tax evasion have attracted a great deal of attention. However, there is still a lack of substantial empirical evidence about the determinants of compliance. The aim of this paper is to investigate empirically whether women are more willing to be compliant than men and whether we observe (among women and in general) differences in attitudes among similar age groups in different time periods (cohort effect) or changing attitudes of the same cohorts over time (age effect) using data from eight Western European countries from the World Values Survey and the European Values Survey that span the period from 1981 to 1999. The results reveal higher willingness to comply among women and an age rather than a cohort effect. Working Paper 06-5
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