Genotypic variation in phosphorus efficiency between wheat cultivars grown under greenhouse and field conditions

Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weight and grain yield under both experimental conditions. In the greenhouse experiment, the increases in shoot dry weight under adequate P supply (80 mg kg(-1)) were from 0% (cv: C-1252) to 34% (cv: Dagdas). Under field conditions, the cultivars showed much greater variation in their response to adequate P supply (60 kg ha(-1)): the increases in shoot dry weight and grain yield with adequate P supply were between -2% (cv: Sivas-111/33) and 25% (cv: Kirac-66) for shoot dry matter production at the heading stage and between 0% (cv: Kirkpinar-79) and 76% (cv: Kate A-1) for grain yield at maturity. Almost all cultivars behaved totally different in their response to P deficiency under greenhouse and field conditions. Phosphorus efficiency ratios (relative growth) under greenhouse conditions did not correlate with the P efficiency ratios under field conditions. In general, durum wheat cultivars were found to be more P efficient compared with bread wheat cultivars. The results of this study indicated that there is wide variation in tolerance to P deficiency among wheat cultivars that can be exploited in breeding new wheat cultivars for high P deficiency tolerance. The results also demonstrated that P efficiency was expressed differently among the wheat cultivars when grown under greenhouse and field conditions and, therefore, special attention should be paid to growth conditions in screening wheat for P efficiency

UK science press officers, professional vision and the generation of expectations

Science press officers can play an integral role in helping promote expectations and hype about biomedical research. Using this as a starting point, this article draws on interviews with 10 UK-based science press officers, which explored how they view their role as science reporters and as generators of expectations. Using Goodwin’s notion of ‘professional vision’, we argue that science press officers have a specific professional vision that shapes how they produce biomedical press releases, engage in promotion of biomedical research and make sense of hype. We discuss how these insights can contribute to the sociology of expectations, as well as inform responsible science communication.This project was funded by the Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034)

Scottish and Newcastle antiemetic pre-treatment for paracetamol poisoning study (SNAP)

BACKGROUND: Paracetamol (acetaminophen) poisoning remains the commonest cause of acute liver injury in Europe and North America. The intravenous (IV) N-acetylcysteine (NAC) regimen introduced in the 1970s has continued effectively unchanged. This involves 3 different infusion regimens (dose and time) lasting over 20 hours. The same weight-related dose of NAC is used irrespective of paracetamol dose. Complications include frequent nausea and vomiting, anaphylactoid reactions and dosing errors. We designed a randomised controlled study investigating the efficacy of antiemetic pre-treatment (ondansetron) using standard NAC and a modified, shorter, regimen. METHODS/DESIGN: We designed a double-blind trial using a 2 × 2 factorial design involving four parallel groups. Pre-treatment with ondansetron 4 mg IV was compared against placebo on nausea and vomiting following the standard (20.25 h) regimen, or a novel 12 h NAC regimen in paracetamol poisoning. Each delivered 300 mg/kg bodyweight NAC. Randomisation was stratified on: paracetamol dose, perceived risk factors, and time to presentation. The primary outcome was the incidence of nausea and vomiting following NAC. In addition the frequency of anaphylactoid reactions and end of treatment liver function documented. Where clinically necessary further doses of NAC were administered as per standard UK protocols at the end of the first antidote course. DISCUSSION: This study is primarily designed to test the efficacy of prophylactic anti-emetic therapy with ondansetron, but is the first attempt to formally examine new methods of administering IV NAC in paracetamol overdose. We anticipate, from volunteer studies, that nausea and vomiting will be less frequent with the new NAC regimen. In addition as anaphylactoid response appears related to plasma concentrations of both NAC and paracetamol anaphylactoid reactions should be less likely. This study is not powered to assess the relative efficacy of the two NAC regimens, however it will give useful information to power future studies. As the first formal randomised clinical trial in this patient group in over 30 years this study will also provide information to support further studies in patients in paracetamol overdose, particularly, when linked with modern novel biomarkers of liver damage, patients at different toxicity risk. TRIAL REGISTRATION: EudraCT number 2009-017800-10, ClinicalTrials.gov IdentifierNCT0105027

Evolution favors protein mutational robustness in sufficiently large populations

BACKGROUND: An important question is whether evolution favors properties such as mutational robustness or evolvability that do not directly benefit any individual, but can influence the course of future evolution. Functionally similar proteins can differ substantially in their robustness to mutations and capacity to evolve new functions, but it has remained unclear whether any of these differences might be due to evolutionary selection for these properties. RESULTS: Here we use laboratory experiments to demonstrate that evolution favors protein mutational robustness if the evolving population is sufficiently large. We neutrally evolve cytochrome P450 proteins under identical selection pressures and mutation rates in populations of different sizes, and show that proteins from the larger and thus more polymorphic population tend towards higher mutational robustness. Proteins from the larger population also evolve greater stability, a biophysical property that is known to enhance both mutational robustness and evolvability. The excess mutational robustness and stability is well described by existing mathematical theories, and can be quantitatively related to the way that the proteins occupy their neutral network. CONCLUSIONS: Our work is the first experimental demonstration of the general tendency of evolution to favor mutational robustness and protein stability in highly polymorphic populations. We suggest that this phenomenon may contribute to the mutational robustness and evolvability of viruses and bacteria that exist in large populations

Order-of-magnitude speedup for steady states and traveling waves via Stokes preconditioning in Channelflow and Openpipeflow

Steady states and traveling waves play a fundamental role in understanding hydrodynamic problems. Even when unstable, these states provide the bifurcation-theoretic explanation for the origin of the observed states. In turbulent wall-bounded shear flows, these states have been hypothesized to be saddle points organizing the trajectories within a chaotic attractor. These states must be computed with Newton's method or one of its generalizations, since time-integration cannot converge to unstable equilibria. The bottleneck is the solution of linear systems involving the Jacobian of the Navier-Stokes or Boussinesq equations. Originally such computations were carried out by constructing and directly inverting the Jacobian, but this is unfeasible for the matrices arising from three-dimensional hydrodynamic configurations in large domains. A popular method is to seek states that are invariant under numerical time integration. Surprisingly, equilibria may also be found by seeking flows that are invariant under a single very large Backwards-Euler Forwards-Euler timestep. We show that this method, called Stokes preconditioning, is 10 to 50 times faster at computing steady states in plane Couette flow and traveling waves in pipe flow. Moreover, it can be carried out using Channelflow (by Gibson) and Openpipeflow (by Willis) without any changes to these popular spectral codes. We explain the convergence rate as a function of the integration period and Reynolds number by computing the full spectra of the operators corresponding to the Jacobians of both methods.Comment: in Computational Modelling of Bifurcations and Instabilities in Fluid Dynamics, ed. Alexander Gelfgat (Springer, 2018

Radio Emission from Ultra-Cool Dwarfs

The 2001 discovery of radio emission from ultra-cool dwarfs (UCDs), the very low-mass stars and brown dwarfs with spectral types of ~M7 and later, revealed that these objects can generate and dissipate powerful magnetic fields. Radio observations provide unparalleled insight into UCD magnetism: detections extend to brown dwarfs with temperatures <1000 K, where no other observational probes are effective. The data reveal that UCDs can generate strong (kG) fields, sometimes with a stable dipolar structure; that they can produce and retain nonthermal plasmas with electron acceleration extending to MeV energies; and that they can drive auroral current systems resulting in significant atmospheric energy deposition and powerful, coherent radio bursts. Still to be understood are the underlying dynamo processes, the precise means by which particles are accelerated around these objects, the observed diversity of magnetic phenomenologies, and how all of these factors change as the mass of the central object approaches that of Jupiter. The answers to these questions are doubly important because UCDs are both potential exoplanet hosts, as in the TRAPPIST-1 system, and analogues of extrasolar giant planets themselves.Comment: 19 pages; submitted chapter to the Handbook of Exoplanets, eds. Hans J. Deeg and Juan Antonio Belmonte (Springer-Verlag

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction

We present evidence for the flavor-changing neutral current decay $B\to K^*\ell^+\ell^-$ and a measurement of the branching fraction for the related process $B\to K\ell^+\ell^-$, where $\ell^+\ell^-$ is either an $e^+e^-$ or $\mu^+\mu^-$ pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises $123\times 10^6$ $\Upsilon(4S)\to B\bar{B}$ decays collected with the Babar detector at the PEP-II $e^+e^-$ storage ring. Averaging over $K^{(*)}$ isospin and lepton flavor, we obtain the branching fractions ${\mathcal B}(B\to K\ell^+\ell^-)=(0.65^{+0.14}_{-0.13}\pm 0.04)\times 10^{-6}$ and ${\mathcal B}(B\to K^*\ell^+\ell^-)=(0.88^{+0.33}_{-0.29}\pm 0.10)\times 10^{-6}$, where the uncertainties are statistical and systematic, respectively. The significance of the $B\to K\ell^+\ell^-$ signal is over $8\sigma$, while for $B\to K^*\ell^+\ell^-$ it is $3.3\sigma$.Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let