Contents of α-tocopherol and β-carotene in grasses and legumes harvested at different maturities

Concentrations of α-tocopherol and β-carotene in forage species at various maturities were studied in Scandinavia. Red clover (RC)/timothy (TI), RC/meadow fescue (MF), and birdsfoot trefoil (BT)/TI mixtures were grown in Skara and Umeå, Sweden. RC/TI,RC/perennial ryegrass (PR), white clover/PR and BT/TI were grown in Foulum, Denmark. Forages in Sweden were cut one week before heading (BH), at heading and one week after heading of TI. The regrowth was cut six and eight weeks after each harvest in the spring growth cycle. In Denmark, one first harvest and three regrowths were taken. Results from Skara and Foulum are presented. Highest concentrations of α-tocopherol and β-carotene (mg kg-1 DM) in legumes were found in BT grown in Skara (49.8 and 69.6 in spring growth cycle,48.1 and 79.8 in regrowth) and in Foulum (81.3 and 89.2). MF had more α-tocopherol and β-carotene than TI in the spring growth cycle (73.5 and 54.2 vs. 46.9 and 43.0 mg kg-1 DM). Highest concentrations of vitamins in the regrowth were found six weeks after BH with 71.8 and 104.8 mg α-tocopherol and 99.6 and 73.1 mg β-carotene kg-1 DM in legumes and grasses,respectively

Ribbon turbulence

Copyright (year) AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Phys. Fluids 26, 126605 (2014) and may be found at http://scitation.aip.org/content/aip/journal/pof2/26/12/10.1063/1.4904878We investigate the non-linear equilibration of a two-layer quasi-geostrophic ow in a channel with an initial eastward baroclinically unstable jet in the upper layer, paying particular attention to the role of bottom friction. In the limit of low bottom friction, classical theory of geostrophic turbulence predicts an inverse cascade of kinetic energy in the horizontal with condensation at the domain scale and barotropization in the vertical. By contrast, in the limit of large bottom friction, the ow is dominated by ribbons of high kinetic energy in the upper layer. These ribbons correspond to meandering jets separating regions of homogenized potential vorticity. We interpret these results by taking advantage of the peculiar conservation laws satis ed by this system: the dynamics can be recast in such a way that the initial eastward jet in the upper layer appears as an initial source of potential vorticity levels in the upper layer. The initial baroclinic instability leads to a turbulent ow that stirs this potential vorticity eld while conserving the global distribution of potential vorticity levels. Statistical mechanical theory of the 11/2 layer quasi-geostrophic model predicts the formation of two regions of homogenized potential vorticity separated by a minimal interface. We explain that cascade phenomenology leads to the same result. We then show that the dynamics of the ribbons results from a competition between a tendency to reach the equilibrium state and baroclinic instability that induces meanders of the interface. These meanders intermittently break and induce potential vorticity mixing, but the interface remains sharp throughout the ow evolution. We show that for some parameter regimes, the ribbons act as a mixing barrier which prevents relaxation toward equilibrium, favouring the emergence of multiple zonal (eastward) jet

Rate of photon production from hot hadronic matter

Thermal photon emission rates from hot hadronic matter are studied to order $e^{2}g^{4}$, where $g$ indicates a strong-interaction coupling constant. Radiative decay of mesons, Compton and annihilation processes for hadrons, and bremsstrahlung reactions are all considered. Compared to the standard rates from the literature, one finds two orders of magnitude increase for low photon energies stemming mainly from bremsstrahlung and then a modest increase (factor of 2) for intermediate and high energy photons owing to radiative decays for a variety of mesons and from other reactions involving strangeness. These results could have important consequences for electromagnetic radiation studies at RHIC.Comment: 5 pages LaTeX, 4 Postscript figure

Vitaminer og fedtsyrer i hø og ensilage – hvad sker der vid forvejring og lagring?

For at undersøge stabiliteten af vitaminer i moderne ensilage- og høproduktion, har FØJO III projektet ECOVIT, igennem to vækstår, målt vitaminindholdet i forskellige græsmarksafgrøder ved forskellige høsttidspunkter og sletintervaller. Resultaterne viser, at det største tab af vitaminer og umættede fedtsyrer sker i forbindelse med forvejringen, mens tabet i lagringsperioden er begrænset