230 research outputs found

    Feasibility study of an Integrated Program for Aerospace-vehicle Design (IPAD) system. Volume 2: Characterization of the IPAD system, phase 1, task 1

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    The aircraft design process is discussed along with the degree of participation of the various engineering disciplines considered in this feasibility study

    Covrig: a framework for the analysis of code, test, and coverage evolution in real software

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    Copyright 2014 ACM.Software repositories provide rich information about the construction and evolution of software systems. While static data that can be mined directly from version control systems has been extensively studied, dynamic metrics concerning the execution of the software have received much less attention, due to the inherent difficulty of running and monitoring a large number of software versions. In this paper, we present Covrig, a flexible infrastructure that can be used to run each version of a system in isolation and collect static and dynamic software metrics, using a lightweight virtual machine environment that can be deployed on a cluster of local or cloud machines. We use Covrig to conduct an empirical study examining how code and tests co-evolve in six popular open-source systems. We report the main characteristics of software patches, analyse the evolution of program and patch coverage, assess the impact of nondeterminism on the execution of test suites, and investigate whether the coverage of code containing bugs and bug fixes is higher than average

    Maintaining a Septic Tank System

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    Once a septic tank and absorption field are installed, you can do several things to prolong their life, thus protecting an investment which may cost 2500ormore.Hereareseveraltipsyoucanfollow.Oftenoverlookedorneglectedisthefactthatseptictanksshouldbeinspectedatleastonceannually.Ineveryproperlyfunctioningseptictank,sludgeaccumulatesinthebottom.Thissludgeiscomposedofsolidmaterialsandmustberemovedperiodically.Ifthesludgeisnotremoved,theaccumulatedsolidswillbuildupintheseptictankandwillbegintowashoutintotheabsorptionfield.Allowingsolidsfromtheseptictanktowashoutintotheabsorptionfieldwilleventuallyclogittothepointwhereanewfieldwillbeneeded.Mostauthoritiesagreethatforatypicalthree−bedroomhome,a1,000−gallon(3,800I)septictankwillneedtohavethesolidsremovedeverythreetofiveyears.Smallertanksmustbepumpedmoreoften.Septictankadditivesthatcleanthetankareavailable,butthesearegenerallynotrecommended.Someadditivesmaycausethesolidstobeflushedfromtheseptictankintotheabsorptionfield,causingcloggingproblems.Othercompoundsmayproduceaseptictankeffluentwhichwilldestroysoilstructureandcauseprematurefailureofthesoilabsorptionsystem.Todetermineifyourseptictankneedspumping,thethicknessofthesludgecanbemeasuredasillustratedinFigure1.Tomeasurethedepthofthesludge,wrapalongstickwithapieceofrough,whitetowelingandtieitsecurely.Lowerthestickthroughtheinlettee(toavoidthescum)tothebottomofthetank.Waitabout30secondsandremovethestickslowlyandcarefully.Blackparticleswillclingtothetowelindicatingthedepthofthesludge.Thesludgeshouldberemovedifitsdepthisequaltoonethirdormoreoftheliquiddepth.Occasionally,afloatingscumlayermaydevelopinseptictanks.Thisscumlayercanalsocausecloggingandshouldbecheckedannually.Thescumlayerthicknesscanbemeasuredwithastickandhingedflapdevice(Figure1).Pushthestickthroughthescumuntilthehingedflapfallsintothehorizontalposition.Raisethestickuntilyoufeelthebottomofthelayer.Markthesticktoindicatethedepthofthescumlayer.Nowusethesameproceduretolocatethelowerendofthesubmergedinletpipe.Ifthebottomsideofthescumlayeriswithinthreeinches(7.6em)ofthelowerendofthesubmergedinlet,theseptictankshouldbepumped.Mostcommunitieshavecontractorswhopumpseptictanks.Itmaycost2500 or more. Here are several tips you can follow. Often overlooked or neglected is the fact that septic tanks should be inspected at least once annually. In every properly functioning septic tank, sludge accumulates in the bottom. This sludge is composed of solid materials and must be removed periodically. If the sludge is not removed, the accumulated solids will build up in the septic tank and will begin to wash out into the absorption field. Allowing solids from the septic tank to wash out into the absorption field will eventually clog it to the point where a new field will be needed. Most authorities agree that for a typical three-bedroom home, a 1 ,000-gallon (3,800 I) septic tank will need to have the solids removed every three to five years. Smaller tanks must be pumped more often. Septic tank additives that clean the tank are available, but these are generally not recommended. Some additives may cause the solids to be flushed from the septic tank into the absorption field, causing clogging problems. Other compounds may produce a septic tank effluent which will destroy soil structure and cause premature failure of the soil absorption system. To determine if your septic tank needs pumping, the thickness of the sludge can be measured as illustrated in Figure 1. To measure the depth of the sludge, wrap a long stick with a piece of rough, white toweling and tie it securely. Lower the stick through the inlet tee (to avoid the scum) to the bottom of the tank. Wait about 30 seconds and remove the stick slowly and carefully. Black particles will cling to the towel indicating the depth of the sludge. The sludge should be removed if its depth is equal to one third or more of the liquid depth. Occasionally, a floating scum layer may develop in septic tanks. This scum layer can also cause clogging and should be checked annually. The scum layer thickness can be measured with a stick and hinged flap device (Figure 1). Push the stick through the scum until the hinged flap falls into the horizontal position. Raise the stick until you feel the bottom of the layer. Mark the stick to indicate the depth of the scum layer. Now use the same procedure to locate the lower end of the submerged inlet pipe. If the bottom side of the scum layer is within three inches (7.6 em) of the lower end of the submerged inlet, the septic tank should be pumped. Most communities have contractors who pump septic tanks. It may cost 50 or more, but it is necessary for maintaining the life of the absorption field. The contractors pump the contents into a tank truck and dispose of it at an approved treatment site or by proper land application. Be sure the workman who cleans your tank mixes the liquid, sludge and scum before pumping so that all of the material can be removed, not just the liquid. It is not recommended to wash, scrub or disinfect the septic tank when pumping. Similarly, it is not necessary to leave solids in the septic to start it again. Normally, as the septic tank fills, the natural processes begin. Products to seed the system with desirable bacteria are available, but they are also not necessary

    Basic Communication Course Students’ Perceptions of the Purpose and Their Role in the Peer Feedback Process

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    Students enrolled in the basic communication course often engage in peer feedback workshops to enhance presentational speaking competence. As such, peer feedback workshops in the basic communication course provide an opportunity for students to provide and receive feedback on speech form, structure, and delivery (Broeckelman-Post & Hosek, 2014). The present study qualitatively examined data from 110 students enrolled in a basic communication course to determine their perceptions of the peer feedback process and what role(s), if any, they believed they had in the peer feedback process. Our thematic analysis revealed that students’ perceive peer feedback as a form of agency, influence, and skill building and perceive their role as a content editor, audience/body, and performance evaluator. Limitations and future research directions are also discussed

    New Exclusion Limits for the Search of Scalar and Pseudoscalar Axion-Like Particles from "Light Shining Through a Wall"

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    Physics beyond the Standard Model predicts the possible existence of new particles that can be searched at the low energy frontier in the sub-eV range. The OSQAR photon regeneration experiment looks for "Light Shining through a Wall" from the quantum oscillation of optical photons into "Weakly Interacting Sub-eV Particles", such as axion or Axion-Like Particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of 2×14.32 \times 14.3 m. In 2014, this experiment has been run with an outstanding sensitivity, using an 18.5 W continuous wave laser emitting in the green at the single wavelength of 532 nm. No regenerated photons have been detected after the wall, pushing the limits for the existence of axions and ALPs down to an unprecedented level for such a type of laboratory experiment. The di-photon couplings of possible pseudo-scalar and scalar ALPs can be constrained in the nearly massless limit to be less than 3.5⋅10−83.5\cdot 10^{-8} GeV−1^{-1} and 3.2⋅10−83.2\cdot 10^{-8} GeV−1^{-1}, respectively, at 95% Confidence Level.Comment: 6 pages, 6 figure

    Determination of ππ\pi\pi scattering lengths from measurement of π+π−\pi^+\pi^- atom lifetime

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    The DIRAC experiment at CERN has achieved a sizeable production of π+π−\pi^+\pi^- atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave ππ\pi\pi scattering length difference ∣a0−a2∣=(.0.2533−0.0078+0.0080∣stat.−0.0073+0.0078∣syst)Mπ+−1|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1} has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure

    Latest Results of the OSQAR Photon Regeneration Experiment for Axion-Like Particle Search

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    The OSQAR photon regeneration experiment searches for pseudoscalar and scalar axion-like particles by the method of "Light Shining Through a Wall", based on the assumption that these weakly interacting sub-eV particles couple to two photons to give rise to quantum oscillations with optical photons in strong magnetic field. No excess of events has been observed, which constrains the di-photon coupling strength of both pseudoscalar and scalar particles down to 5.7⋅10−85.7 \cdot 10^{-8} GeV−1^{-1} in the massless limit. This result is the most stringent constraint on the di-photon coupling strength ever achieved in laboratory experiments.Comment: 6 pages, 5 figures. appears in Proceedings of the 10th PATRAS Workshop on Axions, WIMPs and WISPs (2014

    Diagnosis of Tuberculosis in the Wild Boar (Sus scrofa): A Comparison of Methods Applicable to Hunter-Harvested Animals

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    To obtain robust epidemiological information regarding tuberculosis (TB) in wildlife species, appropriate diagnostic methods need to be used. Wild boar (Sus scrofa) recently emerged as a major maintenance host for TB in some European countries. Nevertheless, no data is available to evaluate TB post-mortem diagnostic methods in hunter-harvested wild boar. METHODOLOGY/PRINCIPAL FINDINGS: Six different diagnostic methods for TB were evaluated in parallel in 167 hunter-harvested wild boar. Compared to bacteriological culture, estimates of sensitivity of histopathology was 77.8%, gross pathology 72.2%, PCR for the MPB70 gene 66.7%, detection of acid-fast bacilli (AFB) in tissue contact smears 55.6% and in histopathology slides 16.7% (estimated specificity was 96.7%, 100%, 100%, 94.4% and 100%, respectively). Combining gross pathology with stained smears in parallel increased estimated sensitivity to 94.4% (94.4% specificity). Four probable bacteriological culture false-negative animals were identified by Discriminant Function Analysis. Recalculating the parameters considering these animals as infected generated estimated values for sensitivity of bacteriology and histopathology of 81.8%, gross pathology 72.7%, PCR for the MPB70 gene 63.6%, detection of AFB in tissue contact smears 54.5% and in histopathology slides 13.6% (estimated specificity was 100% for gross pathology, PCR, bacteriology and detection of AFB in histopathology slides, 96.7% for histopathology and 94.4% for stained smears). CONCLUSIONS/SIGNIFICANCE: These results show that surveys for TB in wild boar based exclusively on gross pathology considerably underestimate prevalence, while combination of tests in parallel much improves sensitivity and negative predictive values. This finding should thus be considered when planning future surveys and game meat inspection schemes. Although bacteriological culture is the reference test for TB diagnosis, it can generate false-negative results and this should be considered when interpreting data.This study was funded by laboratory funds from Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript

    Intimate partner violence and oral HIV pre-exposure prophylaxis adherence among young African women

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    Objective: To estimate the effect of intimate partner violence (IPV) on oral pre-exposure prophylaxis (PrEP) adherence among adolescent girls and young women (AGYW). Design: We conducted a secondary analysis of data from HIV Prevention Trials Network 082 (HPTN 082), a multisite prospective study designed to assess oral PrEP adherence among AGYW in southern Africa. Methods: We estimated the relative prevalence of high PrEP adherence 3 and 6 months after initiation among AGYW 16 – 25 years who reported a history of any IPV in the past year at enrollment versus AGYW who did not, both overall and by age. High adherence was defined as an intracellular tenofovir-diphosphate concentration at least 700 fmol/ punch or more dried blood spots. Results: Among 409 PrEP-initiating AGYW, half (49%) reported experiencing any IPV by a current/recent partner in the year prior to enrollment. Overall, a similar proportion of AGYW who reported IPV had high PrEP adherence at months 3 and 6 as AGYW who did not report IPV. There was, however, evidence of effect modification by age at month 3: among AGYW less than 21 years old, those who reported IPV were less than half as likely to have high adherence [adjusted PR (aPR) = 0.43, 95% confidence interval (CI) 0.22– 0.86]; among AGYW aged 21 years or older, those who reported IPV were more than twice as likely to have high adherence (aPR = 2.21, 95% CI 1.34– 3.66). At month 6, effect estimates within each age stratum were consistent in direction to those at month 3. Conclusion: IPV events may either impede or motivate PrEP adherence among African AGYW, with age appearing to be an important consideration for IPV-related adherence interventions
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