1,929 research outputs found

    Connecting Terminals and 2-Disjoint Connected Subgraphs

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    Given a graph G=(V,E)G=(V,E) and a set of terminal vertices TT we say that a superset SS of TT is TT-connecting if SS induces a connected graph, and SS is minimal if no strict subset of SS is TT-connecting. In this paper we prove that there are at most (VTT2)3VT3{|V \setminus T| \choose |T|-2} \cdot 3^{\frac{|V \setminus T|}{3}} minimal TT-connecting sets when Tn/3|T| \leq n/3 and that these can be enumerated within a polynomial factor of this bound. This generalizes the algorithm for enumerating all induced paths between a pair of vertices, corresponding to the case T=2|T|=2. We apply our enumeration algorithm to solve the {\sc 2-Disjoint Connected Subgraphs} problem in time O(1.7804n)O^*(1.7804^n), improving on the recent O(1.933n)O^*(1.933^n) algorithm of Cygan et al. 2012 LATIN paper.Comment: 13 pages, 1 figur

    PULMONARY FUNCTION IN RHEUMATOID ARTHRITIS TREATED WITH LOW-DOSE METHOTREXATE: A LONGITUDINAL STUDY

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    Lung volumes and gas exchange were investigated prospectively in 96 patients with rheumatoid arthritis selected without regard to pulmonary disorders and treated with i.m. methotrexate (MTX) injections [mean weekly dose 13.0 mg (5th-95th percentile (5-95 PC) 7.6-20.8)]. Individual changes over time during MTX treatment [mean duration 2.9 yr (5-95 PC 0.4-5.3)] were assessed by regression analyses in each individual. Forced vital capacity (FVQ remained stable in the majority of patients [mean annual change +0.8% (5-95 PC −8.1 to +14.0) of calculated normal value]. In addition, transfer factor using the indicator gas CO (TLCO) was unaltered in most patients [mean annual change − 2.1% (5-95 PC −16.2 to +11.8) of predicted value]. However, there were significant decreases in the forced expiratory volume in 1 s (FEV1) before and after inhalation of 0.2 mg salbutamol [mean annual change - 0.8% (5-;95 PC −8.4 to +3.2) and −1.3% (5-95 PC −7.8 to +3.9) of the FVC measured, respectively]. In addition, there were significant increases in alveolar-arterial Po2, gradients (P(A-a), O2) at rest and after exercise [mean annual change +1.7 mmHg (5-;95 PC −5.2 to +12.2) and +1.8 mmHg (5-95 PC −3.5 to 9.0), respectively]. Nevertheless, the amounts were small in view of the reliability of the methods applied and reflect, at least in part, the normal process of ageing. The annual change in FEV1 /FVC was negatively correlated with FEV1 /FVC at baseline (Rs = − 0.46, P < 0.001). The annual change in TL, co was also negatively correlated with TL, co at baseline (Rs = − 0.31, P = 0.028). No other risk factors for deterioration of lung volumes or gas exchange were found, including mean weekly MTX dose, age, gender, smoking, presence of rheumatoid factor and pulmonary function at baseline. We conclude that MTX has no major effect on pulmonary function in the majority of patients and that there is no evidence that patients with pre-existing pulmonary disease are at increased risk for further deterioration of lung functio

    Tilings, tiling spaces and topology

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    To understand an aperiodic tiling (or a quasicrystal modeled on an aperiodic tiling), we construct a space of similar tilings, on which the group of translations acts naturally. This space is then an (abstract) dynamical system. Dynamical properties of the space (such as mixing, or the spectrum of the translation operator) are closely related to bulk properties of the individual tilings (such as the diffraction pattern). The topology of the space of tilings, particularly the Cech cohomology, gives information on how the original tiling can be deformed. Tiling spaces can be constructed as inverse limits of branched manifolds.Comment: 8 pages, including 2 figures, talk given at ICQ

    Multinet : enabler for next generation enterprise wireless services

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    Wireless communications are currently experiencing a fast migration toward the beyond third-generation (B3G)/fourth generation (4G) era. This represents a generational change in wireless systems: new capabilities related to mobility and new services support is required and new concepts as individual-centric, user-centric or ambient-aware communications are included. One of the main restrictions associated to wireless technology is mobility management, this feature was not considered in the design phase; for this reason, a complete solution is not already found, although different solutions are proposed and are being proposed. In MULTINET project, features as mobility and multihoming are applied to wireless network to provide the necessary network and application functionality enhancements for seamless data communication mobility considering end-user scenario and preferences. The aim of this paper is to show the benefits of these functionalities from the Service Providers and final User point of view

    Recurrence in 2D Inviscid Channel Flow

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    I will prove a recurrence theorem which says that any HsH^s (s>2s>2) solution to the 2D inviscid channel flow returns repeatedly to an arbitrarily small H0H^0 neighborhood. Periodic boundary condition is imposed along the stream-wise direction. The result is an extension of an early result of the author [Li, 09] on 2D Euler equation under periodic boundary conditions along both directions

    EMG to force processing III: estimation of model parameters for the human triceps surae muscle and assessment of the accuracy by means of a torque plate

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    Abstract-The parameters of the active state and the seriestlastic component of the Hill muscle model were estimated for the human calf muscles by means of a &apos;torque plate-on seven normal subjects. Together with the results of the calferSometer experiments (Part II) this yields the complete set of parameters for the EMG to force processor based on the Hill model (Part I). The accuracy of the processor was assessed by means of a set of severe test contractions in which the subjects tilted on one foot at various velocities (slow to as fast as possible). The mechanical work j M$ dr and the integrated torque 5 M dr were calculated for these contractions. M being the torque calculated by the EMG processor and Cp the measured angular velocity. These values of the work and the integrated torque were compared to those obtained with the measured torque M, instead of M. The relative error, for positive work, negative work, and integrated torque was + 6.2&quot;&quot; + 14&apos;; (means + s.d.). Data on the peak values of M -M, are also given. INlRODUCTlON In Part I of this series (Hof and Van den Berg. 1981a) we introduced EMG to force processing by means of an electrical analogue of the Hill muscle model for the human calf muscles. The parameters were given in In this paper we will study the estimation of these parameters by means of a very stiff torque recording device designed for this purpose. which we called a torque plate. For thisestimation we will use fast tilting contractions and very brief isometric contractions. This study completes the estimation of the parameters of the analogue and makes it possible to study its accuracy. The accuracy of the processor was determined by test contractions on the basis of tilting contractions; the subject stood on one leg on the torque plate and went up and down on the ball of one foot. In this type of contraction the calf muscle torque is large and it varies quickly, as well as the angle and angular velocity of the ankle. Because of this we considered it a severe test for the EMG processing method. The accuracy will be given in terms of muscle work W = j M#dt and integrated torque IT = j Mdt. by comparing measured values with processed values

    Limit-(quasi)periodic point sets as quasicrystals with p-adic internal spaces

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    Model sets (or cut and project sets) provide a familiar and commonly used method of constructing and studying nonperiodic point sets. Here we extend this method to situations where the internal spaces are no longer Euclidean, but instead spaces with p-adic topologies or even with mixed Euclidean/p-adic topologies. We show that a number of well known tilings precisely fit this form, including the chair tiling and the Robinson square tilings. Thus the scope of the cut and project formalism is considerably larger than is usually supposed. Applying the powerful consequences of model sets we derive the diffractive nature of these tilings.Comment: 11 pages, 2 figures; dedicated to Peter Kramer on the occasion of his 65th birthda

    The rise of fully turbulent flow

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    Over a century of research into the origin of turbulence in wallbounded shear flows has resulted in a puzzling picture in which turbulence appears in a variety of different states competing with laminar background flow. At slightly higher speeds the situation changes distinctly and the entire flow is turbulent. Neither the origin of the different states encountered during transition, nor their front dynamics, let alone the transformation to full turbulence could be explained to date. Combining experiments, theory and computer simulations here we uncover the bifurcation scenario organising the route to fully turbulent pipe flow and explain the front dynamics of the different states encountered in the process. Key to resolving this problem is the interpretation of the flow as a bistable system with nonlinear propagation (advection) of turbulent fronts. These findings bridge the gap between our understanding of the onset of turbulence and fully turbulent flows.Comment: 31 pages, 9 figure

    How model sets can be determined by their two-point and three-point correlations

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    We show that real model sets with real internal spaces are determined, up to translation and changes of density zero by their two- and three-point correlations. We also show that there exist pairs of real (even one dimensional) aperiodic model sets with internal spaces that are products of real spaces and finite cyclic groups whose two- and three-point correlations are identical but which are not related by either translation or inversion of their windows. All these examples are pure point diffractive. Placed in the context of ergodic uniformly discrete point processes, the result is that real point processes of model sets based on real internal windows are determined by their second and third moments.Comment: 19 page
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