Can grasshoppers spread common bacterial blight in beans?

Non-Peer ReviewedCommon bacterial blight (CBB) is a seed-borne disease of dry bean that is usually spread through rain-splash, particularly when heavy rain or hail damages plants. CBB can cause a reduction in yield and if the seed becomes infected it will become a primary source of inoculum in the next generation. During drought cycles, we often experience heavy grasshopper infestations in Saskatchewan. Not only do grasshoppers reduce crop yield and lay eggs for the following year, but they may also be responsible for spreading disease as they travel through a crop. This could be the result of feeding damage which allows rain to spread disease, or grasshoppers may be carrying the pathogen from plant to plant causing the disease to spread more rapidly through the field. In August 2002, a dry bean breeding nursery at Saskatoon was heavily infected with CBB during the same time frame as a major grasshopper invasion. This research was designed to determine if the grasshoppers themselves can physically spread the disease from plant to plant or if they just damage the plants, making them more susceptible to infection

A Swendsen-Wang update algorithm for the Symanzik improved sigma model

We study a generalization of Swendsen-Wang algorithm suited for Potts models with next-next-neighborhood interactions. Using the embedding technique proposed by Wolff we test it on the Symanzik improved bidimensional non-linear $\sigma$ model. For some long range observables we find a little slowing down exponent ($z \simeq 0.3$) that we interpret as an effect of the partial frustration of the induced spin model.Comment: Self extracting archive fil

Dynamic Monte Carlo Measurement of Critical Exponents

Based on the scaling relation for the dynamics at the early time, a new method is proposed to measure both the static and dynamic critical exponents. The method is applied to the two dimensional Ising model. The results are in good agreement with the existing results. Since the measurement is carried out in the initial stage of the relaxation process starting from independent initial configurations, our method is efficient.Comment: (5 pages, 1 figure) Siegen Si-94-1

Random-cluster multi-histogram sampling for the q-state Potts model

Using the random-cluster representation of the $q$-state Potts models we consider the pooling of data from cluster-update Monte Carlo simulations for different thermal couplings $K$ and number of states per spin $q$. Proper combination of histograms allows for the evaluation of thermal averages in a broad range of $K$ and $q$ values, including non-integer values of $q$. Due to restrictions in the sampling process proper normalization of the combined histogram data is non-trivial. We discuss the different possibilities and analyze their respective ranges of applicability.Comment: 12 pages, 9 figures, RevTeX

The Ionization of the Local Interstellar Medium, as Revealed by FUSE Observations of N, O and Ar toward White Dwarf Stars

FUSE spectra of the white dwarf stars G191-B2B, GD 394, WD 2211-495 and WD 2331-475 cover the absorption features out of the ground electronic states of N I, N II, N III, O I and Ar I in the far ultraviolet, providing new insights on the origin of the partial ionization of the Local Interstellar Medium (LISM), and for the case of G191-B2B, the interstellar cloud that immediately surrounds the solar system. Toward these targets the interstellar abundances of Ar I, and sometimes N I, are significantly below their cosmic abundances relative to H I. In the diffuse interstellar medium, these elements are not likely to be depleted onto dust grains. Generally, we expect that Ar should be more strongly ionized than H (and also O and N whose ionizations are coupled to that of H via charge exchange reactions) because the cross section for the photoionization of Ar I is very high. Our finding that Ar I/H I is low may help to explain the surprisingly high ionization of He in the LISM found by other investigators. Our result favors the interpretation that the ionization of the local medium is maintained by a strong EUV flux from nearby stars and hot gases, rather than an incomplete recovery from a past, more highly ionized condition.Comment: 13 pages, 2 figures. To appear in a special issue of the Astrophysical Journal Letters devoted to the first scientific results from the FUSE missio

A Frontal Dust Storm in the Northern Hemisphere at Solar Longitude 97 : An Unusual Observation by the Emirates Mars Mission

Funding Information: Funding for the development of the EMM mission was provided by the United Arab Emirates Government, and to co‐authors outside of the United Arab Emirates by the Mohammed Bin Rashid Space Centre. This work was also supported by a joint research agreement between the Mohammed Bin Rashid Space Centre and the National Space Science and Technology Center in the United Arab Emirates University. CG, BKG, and RMBY were supported by the United Arab Emirates University Grant “Mars and Earth atmospheric science research at the National Space Science and Technology Center,” G00003407. RMBY was also supported by UAE University grant G00003322.Peer reviewe

QCD as a Quantum Link Model

QCD is constructed as a lattice gauge theory in which the elements of the link matrices are represented by non-commuting operators acting in a Hilbert space. The resulting quantum link model for QCD is formulated with a fifth Euclidean dimension, whose extent resembles the inverse gauge coupling of the resulting four-dimensional theory after dimensional reduction. The inclusion of quarks is natural in Shamir's variant of Kaplan's fermion method, which does not require fine-tuning to approach the chiral limit. A rishon representation in terms of fermionic constituents of the gluons is derived and the quantum link Hamiltonian for QCD with a U(N) gauge symmetry is expressed in terms of glueball, meson and constituent quark operators. The new formulation of QCD is promising both from an analytic and from a computational point of view.Comment: 27 pages, including three figures. ordinary LaTeX; Submitted to Nucl. Phys.