1,360 research outputs found

    Overriding subsuming rules

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    International audienceThis paper is concerned with intelligent agents that are able to perform nonmonotonic reasoning, not only with, but also about general rules with exceptions. More precisely, the focus is on enriching a knowledge base Γ with a general rule that is subsumed by another rule already there. Such a problem is important because evolving knowledge needs not follow logic as it is well-known from e.g. the belief revision paradigm. However, belief revision is mainly concerned with the case that the extra information logically conflicts with Γ. Otherwise, the extra knowledge is simply doomed to extend Γ with no change altogether. The problem here is different and may require a change in Γ even though no inconsistency arises. The idea is that when a rule is to be added, it might need to override any rule that subsumes it: preemption must take place. A formalism dedicated to reasoning with and about rules with exceptions is introduced. An approach to dealing with preemption over such rules is then developed

    Particle models from special Jordan backgrounds and spectral triples

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    We put forward a definition for spectral triples and algebraic backgrounds based on Jordan coordinate algebras. We also propose natural and gauge-invariant bosonic configuration spaces of fluctuated Dirac operators and compute them for general, almost-associative, Jordan, coordinate algebras. We emphasize that the theory so obtained is not equivalent with usual associative noncommutative geometry, even when the coordinate algebra is the self-adjoint part of a CC^*-algebra. In particular, in the Jordan case, the gauge fields are always unimodular, thus curing a long-standing problem in noncommutative geometry

    Characterization of Macrophomina phaseolina Infecting Chia Plants

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    Microbial organisms have caused detrimental effects to agricultural plants by significantly decreasing their plant growth yield and it’s nutritional qualities, leading to high levels of economic losses in society. Salvia Hispanica L., commonly known as chia, is becoming a rising agricultural crop because of its favorable nutritional qualities. Chia seeds have a high concentration of α-linolenic acid, commonly known as omega-3 fatty acids) which provide several different health benefits, in addition to being a rich source of protein and fiber. Chia field trial conducted by the Atamian lab during summer 2018, experienced high levels of disease incidence characterized by root rot, plant wilting, and eventual death of three-month-old chia plants. The fungus was isolated and identified as Macrophomina phaseolina based on its morphological analysis on potato dextrose agar plates. Macrophomina phaseolina is a widespread fungus that causes a high mortality rate in nursery plats as well as in agricultural crops such as soybean, maize, sorghum, and cotton. The fungus damages the root system of the plant host, resulting in the inability of the root to obtain the required nutrients and water for proper growth of the plant. The objective of this project was to use molecular techniques to confirm the accuracy of the morphological analysis and further characterize the fungus at the molecular level. The DNA of Macrophomina phaseolina was cloned through the process of A tailing, ligation, and transformation into E. coli cells, and then plasmids from the surviving cultured E coli. cells were sent to the lab for sequencing of the genes MPK-1, ITS 1 and 2, and SSU rRNA. Using the other strains of Macrophomina phaseolina in the NCBI database, the resulting gene sequences were compared to deduce that the fungus present was Macrophomina phaseolina, and if there was a presence of genetic variability between the strains infecting chia plants to previous cases in other plants

    Prevalence, Predictors & Prevention of Motion Sickness in Zero-G Parabolic Flights

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    INTRODUCTION Zero-G parabolic flight reproduces the weightlessness of space for short periods of time. However motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors. METHODS Airbus Zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20s 0g sandwiched by 20s hypergravity of 1.5-1.8g. The survey covered n=246 person-flights (193 Males 53 Females), aged (M+/-SD) 36.0+/-11.3 years. An anonymous questionnaire included motion sickness rating (1=OK to 6=Vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), anti-motion sickness medication, prior Zero-G experience, anxiety level, and other characteristics. RESULTS Participants had lower MSSQ percentile scores 27.4+/-28.0 than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior Zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender nor anxiety. Sickness ratings in fliers pre-treated with scopolamine (1.81+/-1.58) were lower than for non-medicated fliers (2.93+/-2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, MSSQ, could not account for this. CONCLUSION Motion sickness affected one third of Zero-G fliers, despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior Zero-G flight experience (habituation) and anti-motion sickness medication

    The Lorentzian distance formula in noncommutative geometry

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    For almost twenty years, a search for a Lorentzian version of the well-known Connes' distance formula has been undertaken. Several authors have contributed to this search, providing important milestones, and the time has now come to put those elements together in order to get a valid and functional formula. This paper presents a historical review of the construction and the proof of a Lorentzian distance formula suitable for noncommutative geometry.Comment: 16 pages, final form, few references adde

    Motion Sickness Lessons from the Southern Ocean

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    BACKGROUND: The objectives were to assess the prevalence, severity, and medication taken, and to look for predictive factors, in order to better identify characteristics of passengers at risk of motion sickness during transport from Hobart in Tasmania to the French polar stations in Antarctica. METHODS: There were 239 passengers who were surveyed over 4 yr with 4 round trips per year using the Motion Sickness Susceptibility Questionnaire (MSSQ), Simulator Sickness Questionnaire (SSQ), state-trait anxiety test (STAI -Trait and STAI -State), and general parameters (age, gender, number of trips, jet-lag, direction of the trip), medication, calculation of the distance of each passenger’s cabin to the Centre of Gravity (CoG.). RESULTS: While the passengers had a low intrinsic sensitivity to motion sickness (MSSQ), 94% reported at least one SSQ symptom of motion sickness, and 38% vomited. Five associated factors were discovered: greater initial sensitivity (MSSQ), anticipation of being ill, younger age, higher level of anxiety at midtrip, and greater distance from the CoG. Of the passengers, there were 54% who took anti-motion sickness medication at different times of the trip, however, these passengers experienced more nausea. This could be due to self-selection since they were more sensitive to motion sickness. CONCLUSION: We identified three predictive factors of motion sickness (greater intrinsic susceptibility, younger age, and greater cabin distance from the CoG). For preventive purposes, two associated factors of MS (anticipation of being ill, MSSQ score) were determined to classify three groups of risk of MS to improve passenger care during the trip

    La dynamique fait son cinéma : De l'apport de l'imagerie et des mesures de champs cinématiques pour l'analyse du comportement dynamique des matériaux

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    National audienceDepuis de nombreuses décennies, l'imagerie rapide a permis d'observer des phénomènes se produisant sur des échelles de temps très petites (de l'ordre de la milliseconde voire de la microseconde). Avec l'avènement plus récent des caméras numériques, de nouvelles applications sont possibles (p.ex. la tomographie rapide). L'utilisation quantitative d'images est également possible, notamment grâce aux techniques de corrélation et de stéréocorrélation d'images. Différentes applications seront présentées afin d'illustrer les apports pour l'analyse du comportement mécanique des matériaux sous sollicitations dynamiques

    Reporting Charcoal Rot in Chia and Developing a Susceptibility Assay

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    Chia (Salvia Hispanica) cross breeds were planted in the summer of 2018 with the intent of selective breeding for agricultural benefit. Preexisting pathogens in the soil caused 40-50% fatality of adult plants. This was surprising due to the precursory knowledge that chia has antibiotic and antifungal oils (Elshafie et. al. 2018); chia was only recently documented to be susceptible to Fusarium wilt (Fusarium oxysporum). The primary pathogen responsible was identified as Macrophomina phaseolina (aka charcoal rot); a widespread soilborne pathogen which has multiple commercial hosts (Su et. al. 2001). M. phaesolina on wheat seed vector where used as inoculums (Brandari 2017) for chia to evaluate disease progression and symptoms in chia. Samples of this trial produced M. phaseolina from diseased chia tissues confirming susceptibility to M. phaseolina; in addition carefully sampled root and stem fractions identified the pathology of fungus from root to stem. The two parental varieties of the cross, chia-Pinta and chia-Tropic continue to be compared for their disease resistance to M. phaseolina. Identifying disease resistant genes allows for breeding of resistant cultivars, improving the marketability of chia

    The Joint European Compound Library:boosting precompetitive research

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    The Joint European Compound Library (JECL) is a new high-throughput screening collection aimed at driving precompetitive drug discovery and target validation. The JECL has been established with a core of over 321000 compounds from the proprietary collections of seven pharmaceutical companies and will expand to around 500000 compounds. Here, we analyse the physicochemical profile and chemical diversity of the core collection, showing that the collection is diverse and has a broad spectrum of predicted biological activity. We also describe a model for sharing compound information from multiple proprietary collections, enabling diversity and quality analysis without disclosing structures. The JECL is available for screening at no cost to European academic laboratories and SMEs through the IMI European Lead Factory (http://www.europeanleadfactory.eu/)
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