5,693 research outputs found

    The C-5A active lift distribution control system

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    The ALDCS development and design tasks, ALDCS functional configuration, and resulting challenges encountered while accomplishing the first phase of the program are described. These tasks are establishing system requirements and criteria and synthesizing a system mechanization to meet the desired load alleviation, stability margins, flight safety, and flying qualities performance. Results of the ALDCS development and prototype system flight simulation programs, and control law optimization including system stability, handling qualities and structural load analyses are presented, along with concluding remarks relative to the system design integration

    Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments

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    Background: Eliminating Rhodesian sleeping sickness, the zoonotic form of Human African Trypanosomiasis, can be achieved only through interventions against the vectors, species of tsetse (Glossina). The use of insecticide-treated cattle is the most cost-effective method of controlling tsetse but its impact might be compromised by the patchy distribution of livestock. A deterministic simulation model was used to analyse the effects of spatial heterogeneities in habitat and baits (insecticide-treated cattle and targets) on the distribution and abundance of tsetse. Methodology/Principal Findings: The simulated area comprised an operational block extending 32 km from an area of good habitat from which tsetse might invade. Within the operational block, habitat comprised good areas mixed with poor ones where survival probabilities and population densities were lower. In good habitat, the natural daily mortalities of adults averaged 6.14% for males and 3.07% for females; the population grew 8.46in a year following a 90% reduction in densities of adults and pupae, but expired when the population density of males was reduced to <0.1/km2; daily movement of adults averaged 249 m for males and 367 m for females. Baits were placed throughout the operational area, or patchily to simulate uneven distributions of cattle and targets. Gaps of 2–3 km between baits were inconsequential provided the average imposed mortality per km2 across the entire operational area was maintained. Leaving gaps 5–7 km wide inside an area where baits killed 10% per day delayed effective control by 4–11 years. Corrective measures that put a few baits within the gaps were more effective than deploying extra baits on the edges. Conclusions/Significance: The uneven distribution of cattle within settled areas is unlikely to compromise the impact of insecticide-treated cattle on tsetse. However, where areas of >3 km wide are cattle-free then insecticide-treated targets should be deployed to compensate for the lack of cattle

    OPR

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    The ability to reproduce a parallel execution is desirable for debugging and program reliability purposes. In debugging (13), the programmer needs to manually step back in time, while for resilience (6) this is automatically performed by the the application upon failure. To be useful, replay has to faithfully reproduce the original execution. For parallel programs the main challenge is inferring and maintaining the order of conflicting operations (data races). Deterministic record and replay (R&amp;R) techniques have been developed for multithreaded shared memory programs (5), as well as distributed memory programs (14). Our main interest is techniques for large scale scientific (3; 4) programming models

    Water dimer absorption of visible light

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    International audienceLaboratory measurements of water vapor absorption using cavity ring-down spectroscopy revealed a broad absorption at 405 nm with a quadratic dependence on water monomer concentration, a similar absorption with a linear component at 532 nm, and only linear absorption at 570 nm in the vicinity of water monomer peaks. D2O absorption is weaker and linear at 405 nm. Van't Hoff plots constructed at 405.26 nm suggest that for dimerization, Keq=0.056±0.02 atm?1, ?H°301 K=?16.6±2 kJ mol?1 and ?S°301 K=?80±10 J mol?1 K?1. This transition peaks at 409.5 nm, could be attributed to the 8th overtone of water dimer and the 532 nm absorption to the 6th overtone. It is possible that some lower overtones previously searched for are less enhanced. These absorptions could increase water vapor feed back calculations leading to higher global temperature projections with currently projected greenhouse gas levels or greater cooling from greenhouse gas reductions

    Spectral Study of Asteroids and Laboratory Simulation of Asteroid Organics

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    We investigate the spectra of asteroids at near- and mid-infrared wavelengths. In 2010 and 2011 we reported the detection of 3 ?m and 3.2-3.6 ?m signatures on (24) Themis and (65) Cybele indicative of water-ice and complex organics [1] [2] [3]. We further probed other primitive asteroids in the Cybele dynamical group and Themis family, finding diversity in the shape of their 3 ?m [4] [5] [6] and 10 ?m spectral features [4]. These differences indicated mineralogical and compositional variations within these asteroid populations. Also in the mid-infrared region we studied a larger population of asteroids belonging to the Bus C, D, and S taxanomic classes to understand the relationship between any mineralogy and hydration inferred in the visible and near- infrared with the shape, strength, and slope of the 10 ?m emission. We have discovered that at least 3 of the main Bus taxanomic groups (Cs, Ds, and Ss as defined by their visible spectra) clearly cluster into 3 statistically distinct groups based on their 8-13 ?m spectra. Additionally we have attempted to simulate in a laboratory the possible organic compounds we have detected on two asteroids, using various mixtures containing aromatic and aliphatic hydrocarbons. We find that asteroid (24) Themis and (65) Cybele have ?CH2/?CH3 and NCH2/NCH3 ratios similar to our 3- methylpentane, propane, and hexane residues, suggesting that the organics on these asteroids may be short chained and/or highly branched. The ?CH2/?CH3 and NCH2/NCH3 for asteroid(24)Themis are most consistent with the DISM, and some carbonaceous chondrites. The band centers of the C-H stretch absorptions indicate that both asteroids may have aliphatic carriers chemically bonded to electronegative groups (i.e. aromatics), and some that are not. We also detect a 3.45 ?m feature in the spectra of both asteroids that is present in several dense molecular clouds. Our results suggest an interstellar origin for the organics on (24) Themis, and likely (65) Cybele. The differences in the organics of Themis and Cybele are likely related to variations in thermal processing, irradiation and/or formation region in the solar nebula

    From: Mr. & Mrs. M.M. Hargrove

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    Brain-Related Chronic Pain Disorder Diagnosis and Assessment Method

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    A method for diagnosing and assessing a brain-related chronic pain disorder. The method includes assessing a subject\u27s brain function, deterrnining the probability that a subject is suffering from chronic pain as a result of an abnormal brain function condition by obtaining a quantitative assessment of the subject\u27s brain function, and making a statistical comparison between the subject\u27s quantitative brain function assessment and either a database of quantitative assessments of the brain functions of normal, healthy individuals, or a database of quantitative assessments of the brain functions of individuals known to have been suffering from chronic pain as a result of the abnormal brain function condition

    Radiographic Comparison Using CBCT-PAI and Volumetric Analysis of Endodontically Treated Teeth: A Retrospective Cohort Study

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    Purpose: To assess the changes in CBCT-PAI score as well as 3-D volume of periapical findings associated with endodontically treated roots and to see how these findings change over time. Methods: Retrospective chart review with the following inclusion criteria: 1. At least one tooth was endodontically treated at the endodontic private practice; 2. Patient had a recall examination and the treated tooth was asymptomatic, functional and a CBCT was exposed; 3. CBCT interpretation found a periapical finding associated with the treated tooth; 4. A follow-up recall examination was completed and CBCT exposed. Cases that fulfilled the inclusion criteria had the CBCT volumes evaluated by an oral radiologist and an endodontic resident. Each CBCT had a CBCT-PAI score assigned and 3-D volume of the periapical finding was determined in the initial recall and follow-up recall CBCT images in a randomized and blinded fashion. Results: At total of 38 roots with periapical findings were included with average time elapsed from treatment to initial recall of 7.9 years and an average of 2.88 years between recalls. The change in CBCT-PAI score was not significant (p-value=0.6505). CBCT-PAI score improved in 36%, unchanged in 40% and increased in 24%. The median change in 3-D volume was 0.80mm3 smaller at recall and was not statistically significant (p-value=0.2859). There was a total of 16 cases with volume less than 3.0mm3 at initial recall and 93% of those remained less than 3.0mm3 at follow-up recall. The correlation between volume change and time elapsed since treatment was not statistically significant (r=0.06, p-value=0.7020). Conclusion: Clinicians may consider active surveillance as a treatment option for endodontically treated teeth with periapical findings, especially those that are small in size, as long as the patient is immunocompetent, clinically free of pathologic signs and symptoms and the tooth is functional. Further long-term recall examination is warranted to see how asymptomatic periapical findings change over time
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