1,307 research outputs found

    A view of canonical extension

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    This is a short survey illustrating some of the essential aspects of the theory of canonical extensions. In addition some topological results about canonical extensions of lattices with additional operations in finitely generated varieties are given. In particular, they are doubly algebraic lattices and their interval topologies agree with their double Scott topologies and make them Priestley topological algebras.Comment: 24 pages, 2 figures. Presented at the Eighth International Tbilisi Symposium on Language, Logic and Computation Bakuriani, Georgia, September 21-25 200

    Space and Collective Identities

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    Sowohl Identitäts- als auch Raumkonzepte haben in den einzelnen Wissenschaften bereits verschiedene Konjunkturen durchlaufen. Eine intensive Diskussion über ihre aktuelle Definition sowie die Möglichkeiten und Grenzen ihrer Anwendung in den Altertumswissenschaften fehlt jedoch bislang weitgehend. Die im Sommer 2009 gegründete Cross Sectional Group V (CSG-V) bietet hierfür einen Kommunikationsraum. Für einen die Topoi-Areas übergreifenden Austausch wurden spezielle Kommunikationsformate etabliert, z. B. ein monatlich stattfindendes Forum, ein Lesezirkel und Seminare. Ziel ist es u. a., auf methodisch- konzeptionellem Wege das Kernproblem der Verbindung von räumlich verorteter materieller Kultur mit kollektiven Identitäten zu untersuchen. Häufig wurden und werden hier Identifizierungen vorgenommen, die unreflektiert und ideologisch-politisch aufgeladen sind. Ebenso müssen neue Erkenntnisse aus den Naturwissenschaften methodenkritisch in die Forschung integriert werden, auch um mit den wieder verstärkt auftretenden biologistischen Vorstellungen angemessen umgehen zu können. Dazu ist eine Auseinandersetzung mit wissenschaftsgeschichtlichen Fragestellungen und zeitgeschichtlichen, auf archäologischen Orten und archäologischen Wissensproduktionen basierenden Konstitutionen von Identitäten notwendig. Ferner stellen die Erforschung von Kulturtransfer, durch den die Dynamik von Identitäten und Raum verdeutlicht wird, sowie von sprachlichen und narrativen Identitätsdiskursen, z. B. in Form von Eponymen und Mythen, zentrale Aspekte der Arbeit der CSG-V dar. Aufgrund der Aufgabenstellung der CSG-V werden im Folgenden vor allem der diskutierte Raum- und Identitätsbegriff sowie ihre sechs Arbeitskomponenten vorgestellt und erst dann einige Schwerpunktthemen kurz behandelt

    2,2′-[(E,E)-cis-(Cyclo­hexane-1,4-di­yl)bis­(nitrilo­methanylyl­idene)]diphenol

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    In the title compound, C20H22N2O2, the asymmetric unit contains two independent half-mol­ecules, which are both completed by crystallographic inversion symmetry. The cyclo­hexane rings of both mol­ecules adopt chair conformations; the N atoms are in equatorial orientations in one mol­ecule and in axial orientations in the other. Both mol­ecules feature two intra­molecular O—H⋯N hydrogen bonds, which generate S(6) rings

    Biomechanical effects of a new macrogeometry design of dental implants: an in vitro experimental analysis

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    The purpose of the present study was to measure and compare the insertion torque, removal torque, and the implant stability quotient by resonance frequency analysis in different polyurethane block densities of two implant macrogeometries. Four different polyurethane synthetic bone blocks were used with three cortical thickness: Bone 1 with a cortical thickness of 1 mm, Bone 2 with a cortical thickness of 2 mm, Bone 3 with a cortical thickness of 3 mm, and Bone 4, which was totally cortical. Four groups were created in accordance with the implant macrogeometry (n = 10 per group) and surface treatment: G1—regular implant design without surface treatment; G2—regular implant design with surface treatment; G3—new implant design without surface treatment; G4—new implant design with surface treatment. All implants used were 4 mm in diameter and 10 mm in length and manufactured in commercially pure titanium (grade IV) by Implacil De Bortoli (São Paulo, Brazil). The implants were installed using a computed torque machine, and following installation of the implant, the stability quotient (implant stability quotient, ISQ) values were measured in two directions using Osstell devices. The data were analyzed by considering the 5% level of significance. All implant groups showed similar mean ISQ values without statistical differences (p > 0.05), for the same synthetic bone block: for Bone 1, the value was 57.7 ± 3.0; for Bone 2, it was 58.6 ± 2.2; for Bone 3, it was 60.6 ± 2.3; and for Bone 4, it was 68.5 ± 2.8. However, the insertion torque showed similar higher values for the regular macrogeometry (G1 and G2 groups) in comparison with the new implant macrogeometry (G3 and G4 groups). The analysis of the results found that primary stability does not simply depend on the insertion torque but also on the bone quality. In comparison with the regular implant macrogeometry, the new implant macrogeometry decreased the insertion torque without affecting the implant stability quotient values

    Dual Space of a Lattice as the Completion of a Pervin Space

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    16th International Conference, RAMiCS 2017, Lyon, France, May 15-18, 2017, ProceedingsInternational audienceThis survey paper presents well-known results from a new angle. A Pervin space is a set X equipped with a set of subsets,called the blocks of the Pervin space. Blocks are closed under finite intersections and finite unions and hence form a lattice of subsets of X. Pervin spaces are thus easier to define than topological spaces or (quasi)-uniform spaces. As a consequence, most of the standard topological notions, like convergence and cluster points, specialisation order, filtersand Cauchy filters, complete spaces and completion are much easier to define for Pervin spaces. In particular, the completion of a Pervin space turns out to be the dual space (in the sense of Stone) of the original lattice.We show that any lattice of subsets can be described by a set of inequations of the form u ≤ v, where u and v are elements of its dual space. Applications to formal languages and complexity classes are given.Cet article de synthèse présente des résultats bien connus sous un nouvel angle. Un espace de Pervin est unensemble X équipé d'un ensemble de parties, appelé les blocs de l'espace de Pervin. Les blocs sont fermés par intersection finie et union finie et forment ainsi un treillis de parties de X. Les espaces de Pervin sont doncplus faciles à définir que les espaces topologiques ou les espaces (quasi-)uniformes. Par conséquent, la plupart des notions topologiques, comme la convergence et les points d'adhérence, l'ordre de spécialisation, les filtres de Cauchy, les espaces complets et la complétion sont beaucoup plus faciles à définir pour les espaces Pervin. En particulier, la complétion d'un espace Pervin s'avère être l'espace dual (au sens de Stone) du treillis de départ.Nous montrons que tout treillis de parties peut être décrit par un ensemble d'inéquations de la forme u ≤ v, où u et v sont des éléments de son espace dual. On donne des applications aux langages formels et aux classes de complexité

    Representation of Nelson Algebras by Rough Sets Determined by Quasiorders

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    In this paper, we show that every quasiorder RR induces a Nelson algebra RS\mathbb{RS} such that the underlying rough set lattice RSRS is algebraic. We note that RS\mathbb{RS} is a three-valued {\L}ukasiewicz algebra if and only if RR is an equivalence. Our main result says that if A\mathbb{A} is a Nelson algebra defined on an algebraic lattice, then there exists a set UU and a quasiorder RR on UU such that ARS\mathbb{A} \cong \mathbb{RS}.Comment: 16 page

    Chapter 19: Vulnerability of coastal and estuarine habitats in the Great Barrier Reef to climate change

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    This chapter attempts to address the vulnerability of the CEM in the Great Barrier Reef region to global climate change. It does not consider individual habitats (eg reefs or seagrasses) but goes beyond the individual species and habitat assessments, to consider impacts on the whole coastal marine community complex, and the ecological processes that support its functioning.This is Chapter 19 of Climate change and the Great Barrier Reef: a vulnerability assessment. The entire book can be found at http://hdl.handle.net/11017/13

    Labeling Adipose-Derived Stem Cells with Hoechst 33342: Usability and Effects on Differentiation Potential and DNA Damage

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    Adipose-derived stem cells (ASCs) have been extensively studied in the field of stem cell research and possess numerous clinical applications. Cell labeling is an essential component of various experimental protocols and Hoechst 33342 (H33342) represents a cost-effective and easy methodology for live staining. The purpose of this study was to evaluate the labeling of rat ASCs with two different concentrations of H33342 (0.5 μg/mL and 5 μg/mL), with particular regard to usability, interference with cell properties, and potential DNA damage. Hoechst 33342 used at a low concentration of 0.5 μg/mL did not significantly affect cell proliferation, viability, or differentiation potential of the ASCs, nor did it cause any significant DNA damage as measured by the olive tail moment. High concentrations of 5 μg/mL H33342, however, impaired the proliferation and viability of the ASCs, and considerable DNA damage was observed. Undesirable colabeling of unlabeled cocultivated cells was seen in particular with higher concentrations of H33342, independent of varying washing procedures. Hence, H33342 labeling with lower concentrations represents a usable method, which does not affect the tested cell properties. However, the colabeling of adjacent cells is a drawback of the technique

    Study of two bovine bone blocks (sintered and non-sintered) used for bone grafts: physico-chemical characterization and in vitro bioactivity and cellular analysis

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    High-temperature compression and electron backscatter diffraction (EBSD) techniques were used in a systematic investigation of the dynamic recrystallization (DRX) behavior and texture evolution of the Inconel625 alloy. The true stress–true strain curves and the constitutive equation of Inconel625 were obtained at temperatures ranging from 900 to 1200 °C and strain rates of 10, 1, 0.1, and 0.01 s−1. The adiabatic heating effect was observed during the hot compression process. At a high strain rate, as the temperature increased, the grains initially refined and then grew, and the proportion of high-angle grain boundaries increased. The volume fraction of the dynamic recrystallization increased. Most of the grains were randomly distributed and the proportion of recrystallized texture components first increased and then decreased. Complete dynamic recrystallization occurred at 1100 °C, where the recrystallized volume fraction and the random distribution ratios of grains reached a maximum. This study indicated that the dynamic recrystallization mechanism of the Inconel625 alloy at a high strain rate included continuous dynamic recrystallization with subgrain merging and rotation, and discontinuous dynamic recrystallization with bulging grain boundary induced by twinning. The latter mechanism was less dominan

    Finitely generated free Heyting algebras via Birkhoff duality and coalgebra

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    Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and thus the free algebras can be obtained by a direct limit process. Dually, the final coalgebras can be obtained by an inverse limit process. In order to explore the limits of this method we look at Heyting algebras which have mixed rank 0-1 axiomatizations. We will see that Heyting algebras are special in that they are almost rank 1 axiomatized and can be handled by a slight variant of the rank 1 coalgebraic methods
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