Search for new phenomena in high-mass final states with a photon and a jet from pp collisions at root s=13 TeV with the ATLAS detector

A search is performed for new phenomena in events having a photon with high transverse momentum and a jet collected in 36.7 fb−1 of proton–proton collisions at a centre-of-mass energy of s√ = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The invariant mass distribution of the leading photon and jet is examined to look for the resonant production of new particles or the presence of new high-mass states beyond the Standard Model. No significant deviation from the background-only hypothesis is observed and cross-section limits for generic Gaussian-shaped resonances are extracted. Excited quarks hypothesized in quark compositeness models and high-mass states predicted in quantum black hole models with extra dimensions are also examined in the analysis. The observed data exclude, at 95% confidence level, the mass range below 5.3 TeV for excited quarks and 7.1 TeV (4.4 TeV) for quantum black holes in the Arkani-Hamed–Dimopoulos–Dvali (Randall–Sundrum) model with six (one) extra dimensions

Physiological mechanisms of flooding tolerance in rice : transient complete submergence and prolonged standing water

Partial or complete submergence of shoots of rice (Oryza sativa L.) poses a dual challenge: the roots have to function in anoxic soil and gas exchange between shoots and air becomes restricted to a small aerial portion or is abolished during complete submergence. Adaptation of roots to anoxic and chemically reduced waterlogged soils was reviewed by Kirk et al. (Prog Bot, 2014). With deeper floods the O₂ provision to the roots may decline, because there is a high resistance for gas exchange between floodwater and the submerged part of the foliage. Floodwaters differ greatly in light levels and CO₂ concentrations, thus restricting underwater photosynthesis by varying degrees. During the day, underwater photosynthesis largely determines the O₂ concentrations within submerged rice, whereas, at night, tissue O₂ declines, particularly so in roots. Deepwater rice establishes a 'snorkel' via elongation of aerenchymatous internodes and leaf sheaths; these responses are triggered by ethylene, which acts on two Snorkel genes encoding ethylene-responsive factor (ERF) transcriptional regulators to elicit the action of gibberellin. In addition, aquatic roots emerge from stem nodes. Perversely, pronounced shoot elongation can be catastrophic for lowland rice completely submerged during transient floods. In these circumstances tolerance is underpinned by suppression of elongation by SUB1A-1, an ERF transcriptional regulator that blocks ethylene responsiveness. However, many aspects of survival during transient complete submergence remain unclear, such as the role of carbohydrate depletion, photosynthesis under water, and anoxia tolerance in roots. After desubmergence, possible injury to shoots from water deficits and free radicals also requires further elucidation. This review is focused on the evaluation of the physiological mechanisms involved in the acclimation-adaptation of rice to these floods.53 page(s