19 research outputs found

    Algebraic Approach to Logical Inference Implementation

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    The paper examines the usage potential of n-tuple algebra (NTA) developed by the authors as a theoretical generalization of structures and methods applied in intelligence systems. NTA supports formalization of a wide set of logical problems (abductive and modified conclusions, modelling of graphs, semantic networks, expert rules, etc.). This article mostly describes implementation of logical inference by means of NTA. Logical inference procedures in NTA can include, besides the known logical calculus methods, new algebraic methods for checking correctness of a consequence or for finding corollaries to a given axiom system. Inference methods consider (above feasibility of certain substitutions) inner structure of knowledge to be processed, thus providing faster solving of standard logical analysis tasks. Matrix properties of NTA objects allow to decrease laboriousness of intellectual procedures as well as to efficiently parallel logical inference algorithms. In NTA, we discovered new structural and statistical classes of conjunctive normal forms whose satisfiability can be detected for polynomial time. Consequently, many algorithms whose complexity evaluation is theoretically high, e.g. exponential, can in practice be solved in polynomial time, on the average. As for making databases more intelligent, NTA can be considered an extension of relational algebra to knowledge processing. In the authors' opinion, NTA can become a methodological basis for creating knowledge processing languages

    Inductive Generalization in Logical Inference and Techniques to Estimate It

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    The paper presents a novel approach to problems of deductive reasoning in frames of n-tuple algebra (NTA) earlier developed by the authors. Investigations of such problems let us determine the minimal consequence in logical inference and develop techniques to find it. Besides, we have proved that many formally correct consequences are inductive generalizations of this minimal consequence. An NTA-based method is proposed to obtain a numerical estimation for the degree of such an inductive generalization. In particular, it becomes possible to predict the number of consequences for a given system of premises and the share of a minimal consequence in a universe

    Fibrogenic fibroblasts increase intercellular adhesion strength by reinforcing individual OB-cadherin bonds

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    We have previously shown that the switch from N-cadherin to OB-cadherin expression increases intercellular adhesion between fibroblasts during their transition from a migratory to a fibrogenic phenotype. Using atomic force microscopy we here show that part of this stronger adhesion is accomplished because OB-cadherin bonds resist similar to twofold higher forces compared with N-cadherin junctions. By assessing the adhesion force between recombinant cadherin dimers and between native cadherins in the membrane of spread fibroblasts, we demonstrate that cadherin bonds are reinforced over time with two distinct force increments. By modulating the degree of lateral cadherin diffusion and F-actin organization we can attribute the resulting three force states to the single-molecule bond rather than to cadherin cluster formation. Notably, association with actin filaments enhances cadherin adhesion strength on the single-molecule level up to threefold; actin depolymerization reduces single-bond strength to the level of cadherin constructs missing the cytoplasmic domain. Hence, fibroblasts reinforce intercellular contacts by: (1) switching from N- to OB-cadherin expression; (2) increasing the strength of single-molecule bonds in three distinct steps; and (3) actin-promoted intrinsic activation of cadherin extracellular binding. We propose that this plasticity adapts fibroblast adhesions to the changing mechanical microenvironment of tissue under remodeling

    Interplay of ferromagnetism and triplet superconductivity in a Josephson junction

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    In this paper we extend our earlier analysis of the novel Josephson effect in triplet superconductor--ferromagnet--triplet superconductor (TFT) junctions [B. Kastening \emph{et al.}, Phys. Rev. Lett. {\bf{96}}, 047009 (2006)]. In our more general formulation of the TFT junction we allow for potential scattering at the barrier and an arbitrary orientation of the ferromagnetic moment. Several new effects are found upon the inclusion of these extra terms: for example, we find that a Josephson current can flow even when there is vanishing phase difference between the superconducting condensates on either side of the barrier. The critical current for a barrier with magnetization parallel to the interface is calculated as a function of the junction parameters, and is found to display strong non-analyticities. Furthermore, the Josephson current switches first identified in our previous work are found to be robust features of the junction, while the unconventional temperature-dependence of the current is very sensitive to the extra terms in the barrier Hamiltonian.Comment: 24 pages, 15 figure

    The Magnetoelectric Effect in Transition Metal Oxides: Insights and the Rational Design of New Materials from First Principles

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    The search for materials displaying a large magnetoelectric effect has occupied researchers for many decades. The rewards could include not only advanced electronics technologies, but also fundamental insights concerning the dielectric and magnetic properties of condensed matter. In this article, we focus on the magnetoelectric effect in transition metal oxides and review the manner in which first-principles calculations have helped guide the search for (and increasingly, predicted) new materials and shed light on the microscopic mechanisms responsible for magnetoelectric phenomena.Comment: 24 pages, 12 figure

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    Mathematics for logical computer-aided analysis of decisions in agromarketing

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    Collecting data on possible solutions and comparing them should be an integral part of any research in agromarketing. Publications on this topic offer a number of quantitative methods for carrying out such an analysis, but their reliability depends significantly on the accuracy of the initial data, which is usually low. This article describes a logical framework for detecting uncertainties, inconsistencies, and contradictions in the information regarding possible decisions with using our previously developed n-tuple algebra. In our opinion, this allows to computerize an important part of planning tasks in agromarketing and provides good means to objectify and enrich results of any analysis of decision options

    Strength and deformation of polymer pieces at the light industry

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    The article is devoted to elaboration of engineering method to evaluate both strength and deformation of polymer details at light industry on the shoe sole example. Analytical dependences for determining the strength and deflection of a cantilever beam made of viscoelastic material are obtained. These dependences allow to estimate the behavior of the shoe soles with high heels while wearing the shoes. In mathematical modeling of cantilever beam load the material properties that do not meet Hooke's law are taken into account. Strength calculations provide the possibility to determine the sole’s optimal geometric parameters, namely its thickness and the shape of the running surface corrugations. Deflection calculations allow predicting the sole deformation value respectively to the heel at the time of its contact with the ground surface to ensure shoes form stability

    Breaking Rayleigh's curse for multi-parameter objects using BLESS technique

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    According to the Rayleigh criterion, it is impossible to resolve two statistically independent point sources separated by a distance below the width of the point spread function (PSF). Almost twenty years ago it was shown that the distance between two point sources can be statistically estimated with an accuracy better than the PSF width. However, the estimation error increases with decreasing distance. This effect was informally named Rayleigh's curse. Next, it was demonstrated that PSF shaping allows breaking the curse provided that all other source parameters except for the distance, are known a priori. In this work, we propose a new imaging technique based on the target Beam moduLation and the Examination of Shot Statistics (BLESS). Using the Fisher information approach, we show that the technique can break Rayleigh's curse even for unbalanced point sources with unknown centroid and intensity ratio
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