Lattice calculation of 1−+1^{-+} hybrid mesons with improved Kogut-Susskind fermions

We report on a lattice determination of the mass of the exotic $1^{-+}$ hybrid meson using an improved Kogut-Susskind action. Results from both quenched and dynamical quark simulations are presented. We also compare with earlier results using Wilson quarks at heavier quark masses. The results on lattices with three flavors of dynamical quarks show effects of sea quarks on the hybrid propagators which probably result from coupling to two meson states. We extrapolate the quenched results to the physical light quark mass to allow comparison with experimental candidates for the $1^{-+}$ hybrid meson. The lattice result remains somewhat heavier than the experimental result, although it may be consistent with the $\pi_1(1600)$.Comment: 24 pages, 12 figures. Replaced to match published versio

Wave Function Based Characteristics of Hybrid Mesons

We propose some extensions of the quark potential model to hybrids, fit them to the lattice data and use them for the purpose of calculating the masses, root mean square radii and wave functions at the origin of the conventional and hybrid charmonium mesons. We treat the ground and excited gluonic field between a quark and an antiquark as in the Born-Oppenheimer expansion, and use the shooting method to numerically solve the required Schr$\ddot{\textrm{o}}$dinger equation for the radial wave functions; from these wave functions we calculate the mesonic properties. For masses we also check through a Crank Nichelson discretization. For hybrid charmonium mesons, we consider the exotic quantum number states with $J^{PC} = 0^{+ -}, 1^{- +}$ and $2^{+ -}$. We also compare our results with the experimentally observed masses and theoretically predicted results of the other models. Our results have implications for scalar form factors, energy shifts, magnetic polarizabilities, decay constants, decay widths and differential cross sections of conventional and hybrid mesons.Comment: 13 pages, 6 figures, Erratum is submitted to EPJ

Interactions between marine megafauna and plastic pollution in Southeast Asia

Southeast (SE) Asia is a highly biodiverse region, yet it is also estimated to cumulatively contribute a third of the total global marine plastic pollution. This threat is known to have adverse impacts on marine megafauna, however, understanding of its impacts has recently been highlighted as a priority for research in the region. To address this knowledge gap, a structured literature review was conducted for species of cartilaginous fishes, marine mammals, marine reptiles, and seabirds present in SE Asia, collating cases on a global scale to allow for comparison, coupled with a regional expert elicitation to gather additional published and grey literature cases which would have been omitted during the structured literature review. Of the 380 marine megafauna species present in SE Asia, but also studied elsewhere, we found that 9.1 % and 4.5 % of all publications documenting plastic entanglement (n = 55) and ingestion (n = 291) were conducted in SE Asian countries. At the species level, published cases of entanglement from SE Asian countries were available for 10 % or less of species within each taxonomic group. Additionally, published ingestion cases were available primarily for marine mammals and were lacking entirely for seabirds in the region. The regional expert elicitation led to entanglement and ingestion cases from SE Asian countries being documented in 10 and 15 additional species respectively, highlighting the utility of a broader approach to data synthesis. While the scale of the plastic pollution in SE Asia is of particular concern for marine ecosystems, knowledge of its interactions and impacts on marine megafauna lags behind other areas of the world, even after the inclusion of a regional expert elicitation. Additional funding to help collate baseline data are critically needed to inform policy and solutions towards limiting the interactions of marine megafauna and plastic pollution in SE Asia

High-precision 40Ar/39AR age of the gas emplacement into the Songliao Basin

The problem of determining an exact isotopic age of hydrocarbon emplacement is complex because minerals suitable for dating with common isotopic methods are often lacking in the sedimentary domain. However, the igneous quartz from the Cretaceous volcanic rocks that host the gas reservoir in the Songliao Basin (northeastern China), contains abundant secondary fluid inclusions with high concentrations of K and high partial pressures of methane trapped during gas emplacement. Quartz with abundant K-rich fluid inclusions provides an excellent closed system well suited fo

Regulation of estrogen receptor-mediated long range transcription via evolutionarily conserved distal response elements

10.1074/jbc.M802024200Journal of Biological Chemistry2834732977-32988JBCH

Improvement of crucifer IPM in the Changjiang River Valley, China: From research to practice

Crucifers comprise a major group of vegetable crops in the Changjiang River Valley, China. The control of insect pests on crucifer vegetable crops has largely relied on the heavy use of chemical insecticides in the last 30 years, resulting in serious consequences of insecticide resistance, increased costs of control and insecticide residues hazardous to human health. A group of Chinese and Australian scientists have undertaken a joint venture to develop practical and sustainable IPM strategies for crucifer vegetable crops in this region. The work consists of three overlapping and ongoing phases: problem definition, research and development, and implementation. Natural enemies were surveyed and evaluated. Biological and selective insecticides were screened through bioassays and field tests. Damage relationships by various insect pests were assessed by artificial defoliation and natural infestation of plants. It was found that cabbages could endure some defoliation without reduction of head weight, but that the level of compensation varied with the growth stages being attacked. Plants at the pre-heading or mid-late heading stages could endure substantial damage while plants at transplant or cupping to early heading stage were sensitive to damage. These findings on various components interrelated to IPM were used to develop management strategies at the crop system level, which were tested in the field. Field IPM trials across several seasons and localities showed that the new strategy could offer effective control of all insect pests. Compared with conventional methods, IPM practices could usually reduce insecticide input by as much as 30-70%, with little risk of crop loss. Implementation activities included grower involvement in field trials, field days and participatory workshops as well as frequent dissemination of fact sheets. Evidence shows that a substantial improvement in farmers' knowledge, attitude and approaches towards IPM has been achieved in the project areas. The future challenges to and opportunities for improving crucifer IPM in China are discussed