592 research outputs found

    Propositional Encoding of Constraints over Tree-Shaped Data

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    We present a functional programming language for specifying constraints over tree-shaped data. The language allows for Haskell-like algebraic data types and pattern matching. Our constraint compiler CO4 translates these programs into satisfiability problems in propositional logic. We present an application from the area of automated analysis of (non-)termination of rewrite systems

    Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination.

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    Abstract Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) from water vapour discharge are measured by optical emission spectroscopy and Langmuir probe under several operating conditions. Analysis of particle fluxes and removal rates measurements illustrates the role of ion bombardment associated with O radicals, governing the removal rates of organic matter. Auxiliary role of hydroxyl radicals is discussed on the basis of experimental data. The advantages of a water vapour plasma process are discussed for practical applications in medical devices decontamination.</jats:p

    Parallel Form Test-Retest Reliability and Predictive Validity of a Curriculum-Based Measurement Academic Readiness Test

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    The purpose of this study was to help a local school district in rural Iowa determine the reliability and predictive validity of a Curriculum-Based Measurement Academic Readiness Test (CBM-ART). The subjects were 85 kindergarten students and 77 first grade students enrolled in regular education. The total sample of 162 students was approximately 88% Caucasian, 8% Native American, 2% Hispanic, and 2% Asian. Parallel forms of the test were administered at a 14-day interval, with resulting reliability coefficients ranging from .76 to .94 with a median coefficient of .88. Validity coefficients computed between CBM measures administered in kindergarten and Iowa Tests of Basic Skills (ITBS) subtest measures administered in first grade ranged from -.12 to .66 with a median coefficient of .22. Forty-four percent (44%) of the total variance of the ITBS Iowa Grade Equivalent Reading score was accounted for by scores on the CBM-ART. An attempt was also made to investigate predictive validity of the CBM-ART using first grade student report card scores, which met with negative results. Conclusions include (a) the CBM-ART was reliable and (b) compared to other instruments employed in the measurement of academic readiness, there was a reasonable degree of predictive validity concerning the CBMART and reading achievement as measured by the ITBS

    Non-linear Pattern Matching with Backtracking for Non-free Data Types

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    Non-free data types are data types whose data have no canonical forms. For example, multisets are non-free data types because the multiset {a,b,b}\{a,b,b\} has two other equivalent but literally different forms {b,a,b}\{b,a,b\} and {b,b,a}\{b,b,a\}. Pattern matching is known to provide a handy tool set to treat such data types. Although many studies on pattern matching and implementations for practical programming languages have been proposed so far, we observe that none of these studies satisfy all the criteria of practical pattern matching, which are as follows: i) efficiency of the backtracking algorithm for non-linear patterns, ii) extensibility of matching process, and iii) polymorphism in patterns. This paper aims to design a new pattern-matching-oriented programming language that satisfies all the above three criteria. The proposed language features clean Scheme-like syntax and efficient and extensible pattern matching semantics. This programming language is especially useful for the processing of complex non-free data types that not only include multisets and sets but also graphs and symbolic mathematical expressions. We discuss the importance of our criteria of practical pattern matching and how our language design naturally arises from the criteria. The proposed language has been already implemented and open-sourced as the Egison programming language

    Nickel: A micronutrient element for hydrogen-dependent growth of \u3ci\u3eRhizobium japonicum\u3c/i\u3e and for expression of urease activity in soybean leaves

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    Soybean plants and Rhizobium japonicum 122 DES, a hydrogen uptake-positive strain, were cultured in media purified to remove Ni. Supplemental Ni had no significant effect on the dry matter or total N content of plants. However, the addition of Ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, EC 3.5.1.5) in leaves and significantly increased the hydrogenase activity (EC 1.18.3.1) in isolated nodule bacteroids. When cultured under chemolithotrophic conditions, free-living R. japonicum required Ni for growth and for the expression of hydrogenase activity. Hydrogenase activity was minimal or not detectable in cells incubated either without Ni or with Ni and chloramphenicol. Ni is required for derepression of hydrogenase activity and apparently protein synthesis is necessary for the participation of Ni in hydrogenase expression. The addition of Cr, V, Sn, and Pb in place of Ni failed to stimulate the activity of hydrogenase in R. japonicum and urease in soybean leaves. The evidence indicates that Ni is an important micronutrient element in the biology of the soybean plant and R. japonicum

    Observing the variation of asteroid thermal inertia with heliocentric distance

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    Thermal inertia is a useful property to characterise a planetary surface since it can be used as a qualitative measure of the regolith grain size. It is expected to vary with heliocentric distance because of its dependence on temperature. However, no previous investigation has conclusively observed a change in thermal inertia for any given planetary body. We have addressed this by using NEOWISE data and the Advanced Thermophysical Model to study the thermophysical properties of the near-Earth asteroids (1036) Ganymed, (1580) Betulia, and (276049) 2002 CE26 as they moved around their highly eccentric orbits. We confirm that the thermal inertia values of Ganymed and 2002 CE26 do vary with heliocentric distance, although the degree of variation observed depends on the spectral emissivity assumed in the thermophysical modelling. We also confirm that the thermal inertia of Betulia did not change for three different observations obtained at the same heliocentric distance. Depending on the spectral emissivity, the variations for Ganymed and 2002 CE26 are potentially more extreme than that implied by theoretical models of heat transfer within asteroidal regoliths, which might be explained by asteroids having thermal properties that also vary with depth. Accounting for this variation reduces a previously observed trend of decreasing asteroid thermal inertia with increasing size, and suggests that the surfaces of small and large asteroids could be much more similar than previously thought. Furthermore, this variation can affect Yarkovsky orbital drift predictions by a few tens of per cent

    (16) Psyche: A mesosiderite-like asteroid?

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    Asteroid (16) Psyche is the target of the NASA Psyche mission. It is considered one of the few main-belt bodies that could be an exposed proto-planetary metallic core and that would thus be related to iron meteorites. Such an association is however challenged by both its near- and mid-infrared spectral properties and the reported estimates of its density. Here, we aim to refine the density of (16) Psyche to set further constraints on its bulk composition and determine its potential meteoritic analog. We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large program (ID 199.C-0074). We used the high angular resolution of these observations to refine Psyche's three-dimensional (3D) shape model and subsequently its density when combined with the most recent mass estimates. In addition, we searched for potential companions around the asteroid. We derived a bulk density of 3.99\,±\pm\,0.26\,g\cdotcm3^{-3} for Psyche. While such density is incompatible at the 3-sigma level with any iron meteorites (\sim7.8\,g\cdotcm3^{-3}), it appears fully consistent with that of stony-iron meteorites such as mesosiderites (density \sim4.25\,\cdotcm3^{-3}). In addition, we found no satellite in our images and set an upper limit on the diameter of any non-detected satellite of 1460\,±\pm\,200}\,m at 150\,km from Psyche (0.2\%\,×\times\,RHill_{Hill}, the Hill radius) and 800\,±\pm\,200\,m at 2,000\,km (3\%\,×\times\,RHillR_{Hill}). Considering that the visible and near-infrared spectral properties of mesosiderites are similar to those of Psyche, there is merit to a long-published initial hypothesis that Psyche could be a plausible candidate parent body for mesosiderites.Comment: 16 page

    The non-convex shape of (234) Barbara, the first Barbarian

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    Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extremely rich in refractory inclusions, the oldest material ever found in the Solar System. It exhibits several peculiar features, most notably its polarimetric behavior. In recent years other objects sharing the same property (collectively known as "Barbarians") have been discovered. Interferometric observations in the mid-infrared with the ESO VLTI suggested that (234) Barbara might have a bi-lobated shape or even a large companion satellite. We use a large set of 57 optical lightcurves acquired between 1979 and 2014, together with the timings of two stellar occultations in 2009, to determine the rotation period, spin-vector coordinates, and 3-D shape of (234) Barbara, using two different shape reconstruction algorithms. By using the lightcurves combined to the results obtained from stellar occultations, we are able to show that the shape of (234) Barbara exhibits large concave areas. Possible links of the shape to the polarimetric properties and the object evolution are discussed. We also show that VLTI data can be modeled without the presence of a satellite.Comment: 10 pages, 6 figure
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