Non-induced isomorphisms of matrix rings

We give examples of distinct integersi, j, and ringsT for which the matrix ringsM _i (T) andM _j (T) are isomorphic as rings, but for which the free modules _T T ⁽ⁱ⁾ and _T T ⁽ⁱ⁾ are non-isomorphic asT-modules.     

Hand-arm vibration part III: A distributed parameter dynamic model of the human hand-arm system

An anatomically analogous distributed parameter dynamic model of the human arm is proposed and quantitatively validated. Distributed mass and stiffness parameters have been obtained by representing each long bone of the arm as a flexural beam. A distributed damping parameter was introduced by allowing the beam stiffness to be a complex quantity. Hand properties were modelled as a lumped parameter damped spring-mass system. Mechanical driving point impedance techniques were used to verify the model. A dual beam model of the forearm was first proposed, and its frequency response was compared with impedance data collected on the forearm. After having established the validity of the forearm model, it was then extended to include the upper arm. The frequency response of the whole-arm model was then compared with impedance data on the whole arm collected by a previous investigator. It is concluded that the beam model of the human arm adequately represented its dynamic behavior as measured by mechanical driving point impedance techniques. The amount of information concerning the dynamic behavior of the arm yielded by the distributed parameter model is found to be vastly greater than that yielded by lumped parameter models.     

Pion and nucleon dissociation in π−p→π−π+π−p at 205 GeV/c

In a 48 000-picture exposure of the Fermilab 30-inch hydrogen bubble chamber to a 205 GeV/cπ^?beam, we have measured 169 events of the reaction, π^?p→π^?π⁺π^?p, with a cross section of 635 ± 61 μb. This reaction proceeds almost entirely via low mass π^? → 3π and p → pππ dissociation. Factorization is satisfied for p → pππ dissociation in πp and pp interactions.     

Search for the decay πO → 4γ

We have searched for the decay π^O → 4γ using the decay K^± → π^±π^O as a source of kinematically defined π^O,s. No events were observed, where one event would correspond to a branching ratio (π^O → 4γ)/(π^O → 2γ) of 2.7 × 10^?5.     

Measurement of the B-->pi l nu branching fraction and determination of absolute value of V(ub) with tagged B mesons

We report a measurement of the B-->pi l nu branching fraction based on 211 fb(-1) of data collected with the BABAR detector. We use samples of B0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B(0)-->pi- l+ nu) = (1.33+/-0.17stat+/-0.11syst) x 10(-4). We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element absolute value V(ub) by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find absolute value V(ub) = (4.5+/-0.5stat+/-0.3syst(+0.7) -0.5FF x 10(-3), where the last error is due to the normalization of the form factor.     

The Genus of a Digital Image Boundary Is Determined by Its Foreground,Background, and Reeb Graphs

We prove that the genus of the boundary of a digital image is precisely half of the sum of the cycle ranks of three particular graphs: the "foreground graph" and "background graph," which capture topological information about the digital image and its complement, respectively, and the Reeb graph, relative to the natural height function, associated with the digital image's boundary. We prove several additional results, including a characterization of when the cycle rank of the Reeb graph fails to equal the genus of the digital image's boundary (which can happen by virtue of the failure of the natural height function on the boundary of the digital image to be a Morse function).     

The lowest 2A' excited state of the water-hydroxyl complex

Vertical and adiabatic excitation energies of the lowest (2)A(') excited state in the water-hydroxyl complex have been determined using coupled cluster, multireference configuration interaction, multireference perturbation theory, and density-functional methods. A significant redshift of about 0.4 eV in the vertical excitation energy of the complex compared to that of the hydroxyl radical monomer is found with the coupled cluster calculations validating previous results. Electronic excitation leads to a structure with near-equal sharing of the hydroxyl hydrogen by both oxygen atoms and a concomitantly large redshift of the adiabatic excitation energy of approximately 1 eV relative to the vertical excitation energy. The combination of redshifts ensures that the electronic transition in the complex lies well outside the equivalent excitation in the hydroxyl radical monomer. The complex is approximately five times more strongly bound in the excited state than in the ground state.