Modulation of galactic cosmic radiation in interplanetary space by the solar wind

The effect of solar wind on the relative abundances of galactic cosmic rays is assessed using the theories proposed by Parker¹ and Dorman.² The modulation factors for the ratios of electrons, deuterons, tritons and helium nuclei to protons, helium-3 to helium-4 and light (Z=3–5) to medium nuclei (Z=6–9) are presented. The effect of the modulation on the differential energy spectra is studied. The form of the spectra, the position of the maximum in the spectra and the relative reduction over a solar cycle place a restriction on the parameters in the solar wind theory. Starting with plausible galactic spectra and by varying the parameters it is possible to fit the form of the solar minimum spectrum but it does not seem possible to produce the relative reduction between minimum and maximum throughout the energy range, with in the framework of the present solar wind theory.     

Contagion processes on urban bus networks in Indian cities

Bus transportation is the most convenient and cheapest way of public transportation in Indian cities. Due to cost‐effectiveness and wide reachability, buses bring people to their destinations every day. Although the bus transportation has numerous advantages over other ways of public transportation, this mode of transportation also poses a serious threat of spreading contagious diseases throughout the city. It is extremely difficult to predict the extent and spread of such an epidemic. Earlier studies have focused on the contagion processes on scale‐free network topologies; whereas, real‐world networks such as bus networks exhibit a wide‐spectrum of network topology. Therefore, we aim in this study to understand this complex dynamical process of epidemic outbreak and information diffusion on the bus networks for six different Indian cities using SI and SIR models. We identify epidemic thresholds for these networks which help us in controlling outbreaks by developing node‐based immunization techniques. © 2016 Wiley Periodicals, Inc. Complexity 21: 451–458, 2016     

Triple-Resonance Experiments for Correlation of H5 and Exchangeable Pyrimidine Base Hydrogens in C,N-Labeled RNA

Triple-resonance two-dimensional H5(C5C4N)H experiments are described that provide through-bond H5 to imino/amino connectivities in uridines and cytidines in ¹³C, ¹⁵N-labeled RNAs. The experiments employ selective INEPT steps for transferring magnetization from the H5 hydrogens through the intervening C5, C4, and N3/N4 nuclei to the imino/amino hydrogens. The improved sensitivity of these experiments for assignments in a large 43-nucleotide RNA is demonstrated.     

Magic Angle Spinning NMR Spectroscopy with Composite RF Pulses

Using numerical optimization procedures it is shown that it is possible to design composite 180 degrees RF pulses for MAS NMR spectroscopy by explicitly taking into account the variation of the resonance offset of each crystallite during the application of the RF pulses. When using composite RF pulses in experiments such as TOSS, where the delays between the RF pulses have to be critically adjusted, an optimization of these delays can lead to the desired performance characteristics.     

N Chemical Shift Tensor Magnitude and Orientation in the Molecular Frame of Uracil Determined via MAS NMR

The potential of heteronuclear MAS NMR spectroscopy for the characterization of ¹⁵N chemical shift (CS) tensors in multiply labeled systems has been illustrated, in one of the first studies of this type, by a measurement of the chemical shift tensor magnitude and orientation in the molecular frame for the two ¹⁵N sites of uracil. Employing polycrystalline samples of ¹⁵N₂ and 2-¹³C,¹⁵N₂-labeled uracil, we have measured, via ¹⁵N–¹³C REDOR and ¹⁵N–¹H dipolar-shift experiments, the polar and azimuthal angles (θ, ψ) of orientation of the ¹⁵N–¹³C and ¹⁵N–¹H dipolar vectors in the ¹⁵N CS tensor frame. The (θ_NC, ψ_NC) angles are determined to be (92 ± 10°, 100 ± 5°) and (132 ± 3°, 88 ± 10°) for the N1 and N3 sites, respectively. Similarly, (θ_NH, ψ_NH) are found to be (15 ± 5°, −80 ± 10°) and (15 ± 5°, 90 ± 10°) for the N1 and N3 sites, respectively. These results obtained based only on MAS NMR measurements have been compared with the data reported in the literature.     

On the Distances between Latin Squares and the Smallest Defining Set Size

In this note, we show that for each Latin square L of order , there exists a Latin square of order n such that L and differ in at most cells. Equivalently, each Latin square of order n contains a Latin trade of size at most . We also show that the size of the smallest defining set in a Latin square is .     

On induced Folkman numbers

In 1970, Folkman proved that for any graph G there exists a graph H with the same clique number as G. In addition, any r ‐coloring of the vertices of H yields a monochromatic copy of G. For a given graph G and a number of colors r let f(G, r) be the order of the smallest graph H with the above properties. In this paper, we give a relatively small upper bound on f(G, r) as a function of the order of G and its clique number. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 40, 493–500, 2012     

A continuous-time linear complementarity system for dynamic user equilibria in single bottleneck traffic flows

This paper formally introduces a linear complementarity system (LCS) formulation for a continuous-time, multi-user class, dynamic user equilibrium (DUE) model for the determination of trip timing decisions in a simplified single bottleneck model. Existence of a Lipschitz solution trajectory to the model is established by a constructive time-stepping method whose convergence is rigorously analyzed. The solvability of the time-discretized subproblems by Lemke’s algorithm is also proved. Combining linear complementarity with ordinary differential equations and being a new entry to the mathematical programming field, the LCS provides a computational tractable framework for the rigorous treatment of the DUE problem in continuous time; this paper makes a positive contribution in this promising research venue pertaining to the application of differential variational theory to dynamic traffic problems.