25 research outputs found
Towards the glueball spectrum from unquenched lattice QCD
We use a variational technique to study heavy glueballs on gauge
configurations generated with 2+1 flavours of ASQTAD improved staggered
fermions. The variational technique includes glueball scattering states. The
measurements were made using 2150 configurations at 0.092 fm with a pion mass
of 360 MeV. We report masses for 10 glueball states. We discuss the prospects
for unquenched lattice QCD calculations of the oddballs.Comment: 19 pages, 4 tables and 8 figures. One figure added. Now matches the
published versio
An enigma in the genetic responses of plants to salt stresses
Soil salinity is one of the main factors restricting crop production throughout the world. Various salt tolerance traits and the genes controlling these traits are responsible for coping with salinity stress in plants. These coping mechanisms include osmotic tolerance, ion exclusion, and tissue tolerance. Plants exposed to salinity stress sense the stress conditions, convey specific stimuli signals, and initiate responses against stress through the activation of tolerance mechanisms that include multiple genes and pathways. Advances in our understanding of the genetic responses of plants to salinity and their connections with yield improvement are essential for attaining sustainable agriculture. Although a wide range of studies have been conducted that demonstrate genetic variations in response to salinity stress, numerous questions need to be answered to fully understand plant tolerance to salt stress. This chapter provides an overview of previous studies on the genetic control of salinity stress in plants, including signaling, tolerance mechanisms, and the genes, pathways, and epigenetic regulators necessary for plant salinity tolerance
Reducing bias in bacterial community analysis of lower respiratory infections
High-throughput pyrosequencing and quantitative PCR (Q-PCR) analysis offer greatly improved
accuracy and depth of characterisation of lower respiratory infections. However, such approaches
suffer from an inability to distinguish between DNA derived from viable and non-viable bacteria. This
discrimination represents an important step in characterising microbial communities, particularly in
contexts with poor clearance of material or high antimicrobial stress, as non-viable bacteria and
extracellular DNA can contribute significantly to analyses. Pre-treatment of samples with propidium
monoazide (PMA) is an effective approach to non-viable cell exclusion (NVCE). However, the impact
of NVCE on microbial community characteristics (abundance, diversity, composition and structure)
is not known. Here, adult cystic fibrosis (CF) sputum samples were used as a paradigm. The effects
of PMA treatment on CF sputum bacterial community characteristics, as analysed by pyrosequencing
and enumeration by species-specific (Pseudomonas aeruginosa) and total bacterial Q-PCR,
were assessed. At the local community level, abundances of both total bacteria and of P. aeruginosa
were significantly lower in PMA-treated sample portions. Meta-analysis indicated no overall
significant differences in diversity; however, PMA treatment resulted in a significant alteration in
local community membership in all cases. In contrast, at the metacommunity level, PMA treatment
resulted in an increase in community evenness, driven by an increase in diversity, predominately
representing rare community members. Importantly, PMA treatment facilitated the detection of both
recognised and emerging CF pathogens, significantly influencing ‘core’ and ‘satellite’ taxa group
membership. Our findings suggest failure to implement NVCE may result in skewed bacterial
community analyses