4,415 research outputs found

    The relation of semiadjacency of \cap-semigroups of transformations

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    We consider two relations on a \cap-semigroup of partial functions of a given set: the inclusion of domains and the semiadjacencity (i.e., the inclusion of the image of the first function into the domain of the second), which characterized with an abstract point of view using the elementary system of axioms, i.e., system conditions, recorded in the language narrow predicate calculus with equality

    Subtraction Menger algebras

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    Abstract characterizations of Menger algebras of partial nn-place functions defined on a set AA and closed under the set-theoretic difference functions treatment as subsets of the Cartesian product An+1A^{n+1} are given

    Representations of Menger (2,n)(2,n)-semigroups by multiplace functions

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    Investigation of partial multiplace functions by algebraic methods plays an important role in modern mathematics were we consider various operations on sets of functions, which are naturally defined. The basic operation for nn-place functions is an (n+1)(n+1)-ary superposition [][ ], but there are some other naturally defined operations, which are also worth of consideration. In this paper we consider binary Mann's compositions \op{1},...,\op{n} for partial nn-place functions, which have many important applications for the study of binary and nn-ary operations. We present methods of representations of such algebras by nn-place functions and find an abstract characterization of the set of nn-place functions closed with respect to the set-theoretic inclusion

    Biased Information Search in Homogeneous Groups: Confidence as a Moderator for the Effect of Anticipated Task Requirements

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    When searching for information, groups that are homogeneous regarding their members’ prediscussion decision preferences show a strong bias for information that supports rather than conflicts with the prevailing opinion (confirmation bias). The present research examined whether homogeneous groups blindly search for information confirming their beliefs irrespective of the anticipated task or whether they are sensitive to the usefulness of new information for this forthcoming task. Results of three experiments show that task sensitivity depends on the groups’ confidence in the correctness of their decision: Moderately confident groups displayed a strong confirmation bias when they anticipated having to give reasons for their decision but showed a balanced information search or even a disconfirmation bias (i.e., predominately seeking conflicting information) when they anticipated having to refute unterarguments. In contrast, highly confident groups demonstrated a strong confirmation bias independent of the anticipated task requirements

    Bayesian Example Selection Using BaBiES

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    Active learning is widely used to select which examples from a pool should be labeled to give best results when learning predictive models. It is, however, sometimes desirable to choose examples before any labeling or machine learning has occurred. The optimal experimental design literature has many theoretically attractive optimality criteria for example selection, but most are intractable when working with large numbers of predictive features. We present the BaBiES criterion, an approximation of Bayesian A-optimal design for linear regression using binary predictors, which is both simple and extremely fast. Empirical evaluations demonstrate that, in spite of selecting all examples prior to learning, BaBiES is competitive with standard active learning methods for a variety of document classification tasks

    Inverse monoids and immersions of 2-complexes

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    It is well known that under mild conditions on a connected topological space X\mathcal X, connected covers of X\mathcal X may be classified via conjugacy classes of subgroups of the fundamental group of X\mathcal X. In this paper, we extend these results to the study of immersions into 2-dimensional CW-complexes. An immersion f:DCf : {\mathcal D} \rightarrow \mathcal C between CW-complexes is a cellular map such that each point yDy \in {\mathcal D} has a neighborhood UU that is mapped homeomorphically onto f(U)f(U) by ff. In order to classify immersions into a 2-dimensional CW-complex C\mathcal C, we need to replace the fundamental group of C\mathcal C by an appropriate inverse monoid. We show how conjugacy classes of the closed inverse submonoids of this inverse monoid may be used to classify connected immersions into the complex

    Computational selection of inhibitors of Abeta aggregation and neuronal toxicity.

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    Alzheimer\u27s disease (AD) is characterized by the cerebral accumulation of misfolded and aggregated amyloid-beta protein (Abeta). Disease symptoms can be alleviated, in vitro and in vivo, by \u27beta-sheet breaker\u27 pentapeptides that reduce plaque load. However the peptide nature of these compounds, made them biologically unstable and unable to penetrate membranes with high efficiency. The main goal of this study was to use computational methods to identify small molecule mimetics with better drug-like properties. For this purpose, the docked conformations of the active peptides were used to identify compounds with similar activities. A series of related beta-sheet breaker peptides were docked to solid state NMR structures of a fibrillar form of Abeta. The lowest energy conformations of the active peptides were used to design three dimensional (3D)-pharmacophores, suitable for screening the NCI database with Unity. Small molecular weight compounds with physicochemical features and a conformation similar to the active peptides were selected, ranked by docking and biochemical parameters. Of 16 diverse compounds selected for experimental screening, 2 prevented and reversed Abeta aggregation at 2-3microM concentration, as measured by Thioflavin T (ThT) fluorescence and ELISA assays. They also prevented the toxic effects of aggregated Abeta on neuroblastoma cells. Their low molecular weight and aqueous solubility makes them promising lead compounds for treating AD

    PAR2 COST OF PAIN THERAPY FOR OSTEOARTHRITIS IN A PRIVATELY INSURED POPULATION IN THE UNITED STATES

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    Representations of (2,n)(2,n)-semigroups by multiplace functions

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    We describe the representations of (2,n)(2,n)-semigroups, i.e. groupoids with nn binary associative operations, by partial nn-place functions and prove that any such representation is a union of some family of representations induced by Schein's determining pairs.Comment: 17 page
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