Effect of cultivar and soil characteristics on nutritional value in organic and conventional wheat

Evidence of greater nutritional value in organic crops is currently a subject of intense debate. Our objectives in this study were to test for grain mineral concentration in 35 winter wheat cultivars in paired organic and conventional systems, and to determine the influence of cultivar, soil characteristics and farming system on mineral concentration. Here we report preliminary results that show that the grain mineral concentration in organic wheat was higher for copper (Cu), magnesium (Mg), manganese (Mn), phosphorus (P) and zinc (Zn) and lower in calcium (Ca), than the grain mineral concentration in conventional wheat. No difference was found between systems for iron (Fe) concentration. Cultivar was significant in determining mineral concentration for Ca, Cu, Mg, Mn and P. Soil mineral concentration was not responsible for grain mineral concentration, with the exception of P. The organic wheat farming systems had higher grain mineral concentrations of Cu, Mg, Mn, P and Zn than the conventional systems, possibly due in part to increased soil organic matter and pH in the organic systems. Growing specific cultivars capable of exploiting particular soil conditions may be necessary in order to optimize the nutritional value in organic farming systems

A participatory methodology for large scale field trials in the UK

Farmer participation was essential in developing a uniquely useful set of wheat variety trials data on a wide range of organic farms over two years. Although the trials were successful, it became clear that some of the participating farmers felt there were some limitations in the process. These included a lack of ownership in the project and a concern for more researcher help. It was clear that a greater time in-vestment was needed at the start of the project to help with farmer understanding and ownership. De-spite the negative comments, farmers appreciated their involvement, particularly in contrasting their own views and information with that from the wider scene. Farmer participation is essential for systems-level research and this project helped to develop a small core of trained farmers and researchers

Experimental Combat-Stress Model in Rats: Histological Examination of Effects of Amelogenesis-A Possible Measure of Diminished Vagal Tone Episodes

Developmental defects of enamel-stress histomarker rings (accentuated striae) may be a potential measure of diminished vagal tone in research on extreme stress such as exposure to combat. To develop an animal model of this measure, we examined the enamel of rat incisors which erupt continuously. We examined incisors from 15 stressed-colony rats and 7 control-rats for these histomarkers using the Visible Burrow System (VBS). VBS was developed to study combat stress in rats. No stress rings were found in any of the rat incisors examined. In contrast to humans, rats have likely evolved to prioritize incisor strength during combat stress. Studies of amelogenesis during combat stress in other rodents with continuously growing incisors are warranted. Laboratory animals such as rabbits or marmosets may be especially suitable, since they less frequently use their incisors for self defense

A participatory approach to variety trials for organic systems

A participatory research methodology was used to compare the performance of UK wheat varieties under organic conditions. Plots of three breadmaking winter wheat varieties (Hereward, Solstice and Xi19) and a mixture (1:1:1) of the varieties were grown at 19 UK farms in two seasons (2003/04 and 2004/05). Meas-urements were taken of growth habit, yield and grain quality. Grain yields in both seasons showed significant site by variety interactions, although the variation among sites was greater than among varieties in both instances. Wheat grown at Western sites was significantly shorter and higher-yielding than that grown at Eastern sites in 2003/04 but significantly taller in 2004/05. As with grain yield, greater variation among site than variety was found in the Hagberg Falling Number and protein concentra-tion results in both seasons. The results from the two years of trials illustrate the variability of organic systems and the difficulty in selecting a single variety suitable for organic farms

Asymptotic freedom in certain SO(N) and SU(N) models

We calculate the $\beta$-functions for $SO(N)$ and $SU(N)$ gauge theories coupled to adjoint and fundamental scalar representations, correcting long-standing, previous results. We explore the constraints on $N$ resulting from requiring asymptotic freedom for all couplings. When we take into account the actual allowed behavior of the gauge coupling, the minimum value of $N$ in both cases turns out to be larger than realized in earlier treatments. We also show that in the large $N$ limit, both models have large regions of parameter space corresponding to total asymptotic freedom.Comment: 8 pages, no figures. v6: Minor nonsubstantive changes in text and formattin

Renormalizable, asymptotically free gravity without ghosts or tachyons

We analyse scale invariant quadratic quantum gravity incorporating non-minimal coupling to a multiplet of scalar fields in a gauge theory, with particular emphasis on the consequences for its interpretation resulting from a transformation from the Jordan frame to the Einstein frame. The result is the natural emergence of a de Sitter space solution which, depending the gauge theory and region of parameter space chosen, can be free of ghosts and tachyons, and completely asymptotically free. In the case of an SO(10) model, we present a detailed account of the spontaneous symmetry breaking, and we calculate the leading (two-loop) contribution to the dilaton mass.Comment: 22 pages, no figures (Except for the additional "Post-publication note added" and associated reference, v3 is essentially as published.

Optimierung und Validierung eines ex-vivo Kultursystems für trabekulären Knochen

In dieser Arbeit wurde mit dem ZETOS System, einem neuen ex-vivo Kutursystem für trabekulären Knochen gearbeitet. Hauptziel der Arbeit war die Bestimmung der Flussrate in dem ZETOS System, bei der eine optimale physiologische Umgebung für das Wachstum explantierter Knochen gegeben ist. Bei den Untersuchungen stellte sich überraschenderweise heraus, dass die Knochen im experimentellen Ansatz nicht perfundiert werden, sondern der Stofftransport über Diffusion gesteuert wird. Dieser Befund wurde durch Einsatz eines axialen Flusssystems bei gleichem hydrostatischen Druck und durch Diffusionsversuche bestätigt. Das ZETOS System wirkt folglich eher als ein Zirkumfusionssystem als ein Perfusionssystem. Bei der Austestung der beiden Kulturmedien DMEM und BGJb zeigte sich über 26 Kulturtage hinweg, dass BGJb eine Aktivierung von Osteoblasten unabhängig von der angelegten mechanischen Belastung der Knochen induziert. Dies wird in einem Anstieg der relativen Osteoidfläche mit und ohne Belastung sichtbar. In DMEM tritt dagegen keine Veränderung in der relativen Osteoidfläche im Vergleich zum unkultivierten Knochen auf. Bei belasteten und unbelasteten Knochen sind in dem experimentellen Ansatz keine Steifigkeitsveränderungen messbar. Die Analyse der Schnittoberflächen legt den Verdacht nahe, dass eine optimale Kraftübertragung auf den Knochen zu dessen Stimulation nicht gewährleistet war und verbessert werden muss. An Hand der histologischen Beurteilung der Schnitte zeigten sich nach 26- tägiger Kulturdauer keine Anhaltspunkte für einen Vitalitätsverlust der Zellen in dem Kultursystem. Dennoch führten Doppelmarkierungen mit Fluorochromen nur in einer geringen Anzahl der Versuchsansätze zu einer erfolgreichen Messung derWachstumsgeschwindigkeit,die sich in diesen Fällen allerdings im Rahmen der physiologischen Grundwachstumsgeschwindigkeit bewegt. Um die Vitalität der Knochen eindeutig belegen zu können, wird der Einsatz von Verfahren zur Messung der Protein- und DNS-Synthese für zukünftige Optimierungsansätze empfohlen. Letztlich gelang es, zwei Makros zur pixelbasierten Bildanalyse zu erstellen, welche die histologische Auswertung der Schnitte zur Bestimmung der Mineral Aposition Rate (MAR) sowie der relativen Osteoidfläche (Os.Ar/B.Ar) automatisiert ermöglichen