Self-consistent Pomeranchon coupling ratios in the multiperipheral model

Given the two leading eigenvalues and eigenfunctions of the resonance (low-subenergy) component of a multiperipheral kernel and assuming lower eigenvalues to be unimportant, it is shown how the mixture corresponding to the Pomeranchon eigenfunction may be calculated from considerations of self-consistency. The method is illustrated in a multiperipheral model with pseudoscalar-meson links by associating the two leading unperturbed eigenstates with the 2+ particles f(1260) and f′(1514)

Multipole analysis of spin observables in vector meson photoproduction

A multipole analysis of vector meson photoproduction is formulated as a generalization of the pseudoscalar meson case. Expansion of spin observables in the multipole basis and behavior of these observables near threshold and resonances are examined.Comment: 15 pages, latex, 2 figure

Spanning Properties of Theta-Theta Graphs

We study the spanning properties of Theta-Theta graphs. Similar in spirit with the Yao-Yao graphs, Theta-Theta graphs partition the space around each vertex into a set of k cones, for some fixed integer k > 1, and select at most one edge per cone. The difference is in the way edges are selected. Yao-Yao graphs select an edge of minimum length, whereas Theta-Theta graphs select an edge of minimum orthogonal projection onto the cone bisector. It has been established that the Yao-Yao graphs with parameter k = 6k' have spanning ratio 11.67, for k' >= 6. In this paper we establish a first spanning ratio of $7.82$ for Theta-Theta graphs, for the same values of $k$. We also extend the class of Theta-Theta spanners with parameter 6k', and establish a spanning ratio of $16.76$ for k' >= 5. We surmise that these stronger results are mainly due to a tighter analysis in this paper, rather than Theta-Theta being superior to Yao-Yao as a spanner. We also show that the spanning ratio of Theta-Theta graphs decreases to 4.64 as k' increases to 8. These are the first results on the spanning properties of Theta-Theta graphs.Comment: 20 pages, 6 figures, 3 table

A User-Friendly Dynamic Reactor Simulator Built in Microsoft Excel

Computer plant simulation is being used in all aspects of engineering, through many simulation software packages. However, almost all of them require licenses that must be purchased by engineering colleges intending to use simulation in their teaching. As public educational institutions everywhere are facing a scarcity of economic resources, they can resort to a freeware steady-state plant simulator, however, there is no availability of reliable, free dynamic plant simulators. In addition, published experiences on developing dynamic simulators use programming languages requiring paid licenses (e.g. Matlab) and thus have limited relevancy to schools struggling to cut expenses. This article first uses a set of typical college objectives to discuss the advantages of building their own dynamic simulators, and then shows the development of a user-friendly dynamic simulator of a batch reactor constructed entirely within Microsoft Excel, which, in contrast to the programming languages used in related reports, is already widely used by universities around the world

Small Dimensionless Parameter to Characterize Multiple-Pomeranchon Phenomena

We identify a small dimensionless parameter ηP associated with the triple Pomeranchon vertex, which governs both the rate of high-mass diffractive dissociation processes and the fine structure in the J-place spectrum near J=1. Theoretical arguments are given that ηP≾1-αP(0), and a possible experiment to measure ηP is discussed. A formula for ηP, based on a multiperipheral model, shows that in such models this parameter does not vanish, and a connection of ηP with a perturbation formalism for the Pomeranchon propagator is suggested

Balancing Minimum Spanning and Shortest Path Trees

This paper give a simple linear-time algorithm that, given a weighted digraph, finds a spanning tree that simultaneously approximates a shortest-path tree and a minimum spanning tree. The algorithm provides a continuous trade-off: given the two trees and epsilon > 0, the algorithm returns a spanning tree in which the distance between any vertex and the root of the shortest-path tree is at most 1+epsilon times the shortest-path distance, and yet the total weight of the tree is at most 1+2/epsilon times the weight of a minimum spanning tree. This is the best tradeoff possible. The paper also describes a fast parallel implementation.Comment: conference version: ACM-SIAM Symposium on Discrete Algorithms (1993

Magnitude of High-Energy Meson-Meson Total Cross Sections

The total cross section for meson-meson scattering at high energy is calculated using a simple, but plausible, SU(n)-symmetric multiperipheral model. The resulting σT is of the order 16π^3/NMv^2 where Mv is the central mass of the dominant low-energy resonance multiplet in elastic meson-meson scattering and N is the dimensionality of the multiplet of the incident mesons. The nongeometric character of this result is discussed

Updated resonance photo-decay amplitudes to 2 GeV

We present the results of an energy-dependent and set of single-energy partial-wave analyses of single-pion photoproduction data. These analyses extend from threshold to 2 GeV in the laboratory photon energy, and update our previous analyses to 1.8 GeV. Photo-decay amplitudes are extracted for the baryon resonances within this energy range. We consider two photoproduction sum rules and the contributions of two additional resonance candidates found in our most recent analysis of $\pi N$ elastic scattering data. Comparisons are made with previous analyses.Comment: Revtex, 26 pages, 3 figures. Postscript figures available from ftp://clsaid.phys.vt.edu/pub/pr or indirectly from http://clsaid.phys.vt.edu/~CAPS

TIGIT Marks Exhausted T Cells, Correlates with Disease Progression, and Serves as a Target for Immune Restoration in HIV and SIV Infection.

HIV infection induces phenotypic and functional changes to CD8+ T cells defined by the coordinated upregulation of a series of negative checkpoint receptors that eventually result in T cell exhaustion and failure to control viral replication. We report that effector CD8+ T cells during HIV infection in blood and SIV infection in lymphoid tissue exhibit higher levels of the negative checkpoint receptor TIGIT. Increased frequencies of TIGIT+ and TIGIT+ PD-1+ CD8+ T cells correlated with parameters of HIV and SIV disease progression. TIGIT remained elevated despite viral suppression in those with either pharmacological antiretroviral control or immunologically in elite controllers. HIV and SIV-specific CD8+ T cells were dysfunctional and expressed high levels of TIGIT and PD-1. Ex-vivo single or combinational antibody blockade of TIGIT and/or PD-L1 restored viral-specific CD8+ T cell effector responses. The frequency of TIGIT+ CD4+ T cells correlated with the CD4+ T cell total HIV DNA. These findings identify TIGIT as a novel marker of dysfunctional HIV-specific T cells and suggest TIGIT along with other checkpoint receptors may be novel curative HIV targets to reverse T cell exhaustion