On the Mechanism of Open-Flavor Strong Decays

Open-flavor strong decays are mediated by $q\bar q$ pair production, which is known to occur dominantly with \3p0 quantum numbers. The relation of the phenomenological \3p0 model of these decays to ``microscopic" QCD decay mechanisms has never been clearly established. In this paper we investigate $q\bar q$ meson decay amplitudes assuming pair production from the scalar confining interaction (sKs) and from one gluon exchange (OGE). sKs pair production predicts decay amplitudes of approximately the correct magnitude and D/S amplitude ratios in $b_1\to\omega\pi$ and $a_1\to\rho\pi$ which are close to experiment. The OGE decay amplitude is found to be subdominant in most cases, a notable exception being $^3$P$_0\to{}^1$S$_0+{}^1$S$_0$. The full sKs~+~OGE amplitudes differ significantly from \3p0 model predictions in some channels and can be distinguished experimentally, for example through an accurate comparison of the D/S amplitude ratios in $b_1\to\omega\pi$ and $a_1\to\rho\pi$.Comment: 44 pages, 22 eps figures, RevTex, complete postscript file available at http://csep2.phy.ornl.gov/theory_group/people/barnes/pubs/abs.p

Innovative granular formulation of Metarhizium robertsii microsclerotia and blastospores for cattle tick control.

Abstract: The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in economic losses aggravated by tick resistance to chemical acaricides. Strains of Metarhizium spp., a well-known group of entomopathogenic fungi, can contribute to managing this ectoparasite. We explored two novel granular, microsclerotia- or blastospores-based formulations of Metarhizium robertsii for R. microplus control under semi-field conditions. Fungal persistence in soil was also observed for 336 days. The experiment used pots of Urochloa decumbens cv. Basilisk grass, treated with 0.25 or 0.5 mg of granular formulation/cm2 (25 or 50 kg/ha) applied to the soil surface prior to transferring engorged tick females onto the treated soil. The fungal granules yielded more conidia with subsequent sporulation under controlled indoor conditions than in the outdoor environment, where the levels of fungus rapidly declined over time. Metarhizium-root colonization ranged from 25 to 66.7% depending on the propagule and rate. Fungal formulations significantly reduced the number of tick larvae during the humid season, reaching at least 64.8% relative efficacy. Microsclerotia or blastospores-granular formulations of M. robertsii can reduce the impact of R. microplus, and thus prove to be a promising tool in the control of ticks

Quark Delocalization, Color Screening and Dibaryons

The quark delocalization and color screening model, a quark potential model, is used for a systematic search of dibaryon candidates in the $u,d$ and $s$ three flavor world. Color screening which appears in unquenched lattice gauge calculations and quark delocalization (which is similar to electron delocalization in molecular physics) are both included. Flavor symmetry breaking and channel coupling effects are studied. The model is constrained not only by baryon ground state properties but also by the $N$-$N$ scattering phase shifts. The deuteron and zero energy di-nucleon resonance are both reproduced qualitatively. The model predicts two extreme types of dibaryonic systems: ``molecular'' like the deuteron, and highly delocalized six-quark systems among which only a few narrow dibaryon resonances occur in the $u,d$ and $s$ three flavor world. Possible high spin dibaryon resonances are emphasized.Comment: 20 pages, latex, no figure

Fungal entomopathogens: new insights on their ecology

An important mechanism for insect pest control should be the use of fungal entomopathogens. Even though these organisms have been studied for more than 100 y, their effective use in the field remains elusive. Recently, however, it has been discovered that many of these entomopathogenic fungi play additional roles in nature. They are endophytes, antagonists of plant pathogens, associates with the rhizosphere, and possibly even plant growth promoting agents. These findings indicate that the ecological role of these fungi in the environment is not fully understood and limits our ability to employ them successfully for pest management. In this paper, we review the recently discovered roles played by many entomopathogenic fungi and propose new research strategies focused on alternate uses for these fungi. It seems likely that these agents can be used in multiple roles in protecting plants from pests and diseases and at the same time promoting plant growth

Robert L. Danly (image)

Summer Issuehttp://deepblue.lib.umich.edu/bitstream/2027.42/61062/1/1402.pd