The Effect of Defoliation Interval on Regrowth of Tall Fescue

Herbage yield, persistence and quality optimise when defoliation interval is based on physiological indicators, such as leaf regrowth stage. Examples include ryegrass (Fulkerson & Donaghy, 2001), cocksfoot (Rawnsley et al., 2002), prairie grass (Fulkerson et al., 2000) and kikuyu (Reeves et al., 1996). Yield, persistence and quality optimise because leaf regrowth stage relates closely to plant energy reserves, which generally peak as the number of live leaves/tiller maximise. More frequent defoliation than the optimum reduces energy reserves and leads to a smaller root system, fewer tillers and retarded growth rate (Fulkerson & Donaghy, 2001). Based on plant physiological development, the optimum defoliation interval for tall fescue has not been defined

Geometric representation of interval exchange maps over algebraic number fields

We consider the restriction of interval exchange transformations to algebraic number fields, which leads to maps on lattices. We characterize renormalizability arithmetically, and study its relationships with a geometrical quantity that we call the drift vector. We exhibit some examples of renormalizable interval exchange maps with zero and non-zero drift vector, and carry out some investigations of their properties. In particular, we look for evidence of the finite decomposition property: each lattice is the union of finitely many orbits.Comment: 34 pages, 8 postscript figure

The Λp\bf{\Lambda p} interaction studied via femtoscopy in p + Nb reactions at sNN=3.18 GeV\mathbf{\sqrt{s_{NN}}=3.18} ~\mathrm{\bf{GeV}}

We report on the first measurement of $p\Lambda$ and $pp$ correlations via the femtoscopy method in p+Nb reactions at $\mathrm{\sqrt{s_{NN}}=3.18} ~\mathrm{GeV}$, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for $pp$ pairs of $r_{0,pp}=2.02 \pm 0.01(\mathrm{stat})^{+0.11}_{-0.12} (\mathrm{sys}) ~\mathrm{fm}$ and a slightly smaller value for $p\Lambda$ of $r_{0,\Lambda p}=1.62 \pm 0.02(\mathrm{stat})^{+0.19}_{-0.08}(\mathrm{sys}) ~\mathrm{fm}$ is extracted. Using the geometrical extent of the particle emitting region, determined experimentally with $pp$ correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The $p\Lambda$ correlation is proven sensitive to predicted scattering length values from chiral effective field theory. We demonstrate that the femtoscopy technique can be used as valid alternative to the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure

Pfmrk, a MO15-related protein kinase from Plasmodium falciparum. Gene cloning, sequence, stage-specific expression and chromosome localization.

Cyclin-dependent kinases (Cdks) play a central role in the regulation of the eukaryotic cell cycle. A novel gene encoding a Cdk-like protein, Pfmrk, has been isolated from the human malaria parasite Plasmodium falciparum. The gene has no introns and comprises an open reading frame encoding a protein of 324 amino acids with a predicted molecular mass of 38 kDa. Database searches revealed a striking similarity to the Cdk subfamily with the highest similarity to human MO15 (Cdk7). The overall sequence of Pfmrk shares 62% similarity and 46% identity with human MO15, in comparison to the 49-58% similarity and 34-43% identity with other human Cdks. Pfmrk contains two unique inserts: one consisting of 5 amino acids just before the cyclin-binding motif and the other composed of 13 amino acids within the T-loop equivalent region. Southern blots of genomic DNA digests and chromosomal separations showed that Pfmrk is a single-copy gene conserved between several parasite strains and is located on chromosome 10. A 2500-nucleotide transcript of this gene is expressed predominantly in the sexual blood stages (gametocytes), suggesting that Pfmrk may be involved in sexual stage development

Strange hadron production at SIS energies: an update from HADES

We present and discuss recent experimental activities of the HADES collaboration on open and hidden strangeness production close or below the elementary NN threshold. Special emphasis is put on the feed-down from ϕ mesons to antikaons, the presence of the Ξ(-) excess in cold nuclear matter and the comparison of statistical model rates to elementary p+p data. The implications for the interpretation of heavy-ion data are discussed as well

Measurement of global polarization of {\Lambda} hyperons in few-GeV heavy-ion collisions

The global polarization of {\Lambda} hyperons along the total orbital angular momentum of a relativistic heavy-ion collision is presented based on the high statistics data samples collected in Au+Au collisions at \sqrt{s_{NN}} = 2.4 GeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at GSI, Darmstadt. This is the first measurement below the strangeness production threshold in nucleon-nucleon collisions. Results are reported as a function of the collision centrality as well as a function of the hyperon transverse momentum (p_T) and rapidity (y_{CM}) for the range of centrality 0--40%. We observe a strong centrality dependence of the polarization with an increasing signal towards peripheral collisions. For mid-central (20--40%) collisions the polarization magnitudes are (%) = 6.0 \pm 1.3 (stat.) \pm 2.0 (syst.) for Au+Au and (%) = 4.6 \pm 0.4 (stat.) \pm 0.5 (syst.) for Ag+Ag, which are the largest values observed so far. This observation thus provides a continuation of the increasing trend previously observed by STAR and contrasts expectations from recent theoretical calculations predicting a maximum in the region of collision energies about 3 GeV. The observed polarization is of a similar magnitude as predicted by 3D fluid dynamics and the UrQMD plus thermal vorticity model and significantly above results from the AMPT model.Comment: 8 pages, 4 figure