Raman scattering in a Heisenberg {\boldmath S=1/2S=1/2} antiferromagnet on the triangular lattice

We investigate two-magnon Raman scattering from the $S=1/2$ Heisenberg antiferromagnet on the triangular lattice, considering both the effect of renormalization of the one-magnon spectrum by 1/S corrections and final-state magnon-magnon interactions. The bare Raman intensity displays two peaks related to one-magnon van-Hove singularities. We find that 1/S self-energy corrections to the one-magnon spectrum strongly modify this intensity profile. The central Raman-peak is significantly enhanced due to plateaus in the magnon dispersion, the high frequency peak is suppressed due to magnon damping, and the overall spectral support narrows considerably. Additionally we investigate final-state interactions by solving the Bethe-Salpeter equation to $O(1/S)$. In contrast to collinear antiferromagnets, the non-collinear nature of the magnetic ground state leads to an irreducible magnon scattering which is retarded and non-separable already to lowest order. We show that final-state interactions lead to a rather broad Raman-continuum centered around approximately twice the 'roton'-energy. We also discuss the dependence on the scattering geometry.Comment: 7 pages, 5 figure

Development of lubricating oils suitable for use with liquid oxidizers Final summary report, 4 Dec. 1969 - 4 Oct. 1970

Development of lubricating oils suitable for use with liquid oxidizer

Abnormal flowers and pattern formation in floral

“From our acquaintance with this abnormal enabled to unveil the secrets that normal us, and to see distinctly what, from the regular we can only infer.” - J. W. von Goethe (1790

A generalized vortex lattice method for subsonic and supersonic flow applications

If the discrete vortex lattice is considered as an approximation to the surface-distributed vorticity, then the concept of the generalized principal part of an integral yields a residual term to the vorticity-induced velocity field. The proper incorporation of this term to the velocity field generated by the discrete vortex lines renders the present vortex lattice method valid for supersonic flow. Special techniques for simulating nonzero thickness lifting surfaces and fusiform bodies with vortex lattice elements are included. Thickness effects of wing-like components are simulated by a double (biplanar) vortex lattice layer, and fusiform bodies are represented by a vortex grid arranged on a series of concentrical cylindrical surfaces. The analysis of sideslip effects by the subject method is described. Numerical considerations peculiar to the application of these techniques are also discussed. The method has been implemented in a digital computer code. A users manual is included along with a complete FORTRAN compilation, an executed case, and conversion programs for transforming input for the NASA wave drag program

Finishing store lambs from organic hill and upland farms OF0119

1. The aim of this study was to assess the economics and constraints associated with home finishing lambs on a range of organic hill and upland farms in England and Wales, and to evaluate the potential for further finishing on registered farms in the lowlands. 2. The current state of the organic sheep sector is briefly reviewed. This identifies problems of scale, limited premia and uneveness of supply as limiting factors to more rapid development of the market and associated production systems. 3. To quanitfy the effect of organic management on financial performance, hill and upland farms were classified under four typical systems, depending on the degree of intensification. 4. Without a sizeable area of improved ground, to which fertiliser and other inputs could have been applied conventionally, flocks based on high hill or marginal hill systems were least affected by switching to organic management. Flock Gross Margin on the marginal hill declined by approximately 7%. 5. On more intensive farms, typified by Welsh hill or upland farming systems, there is greater potential to finish lambs at higher stocking rates under conventional management, and the consequences of changing to organic management are greatly increased. Assuming a 10% premium for fnished organic lambs, deviating from convetional practice to produce store lambs or finish lambs at higher production cost, reduced flock Gross Margin by approximately 12-15%. Without a premium, this deficit increased to 15-20%. 6. The Organic Aid Scheme can make good the likely income loss during the first two years after conversion, when the highest rates are payable. However, in the long-term organic flocks must compete solely on the basis os a premium paid for finished, and ideally, for store lambs. 7. Physical and financial constraints were identified as t wy systems had not developed linking potential production of store lambs in the hills/uplands with finishing on organic farms in the lowlands. These were mainly scale and infrastructure, availability of suitable feeds and the likely level of return to the lowland farmer from a store lamb finishing enterprise. Potential sources of feed for finishing organic lambs were assessed. These include permanent pasture, short-term leys, catch crops, grazed set-aside land and conserved fodder. 8. Integration with existing organic systems of all types was estimated to have the potential to finish an extra 10-15,000 lambs per annum, equivalent to the number of lambs currently receiving an organic premium. 9. Further opportunities to expand finishing capacity on lowland farms were examined. Mixed organic farms are likely to have little or no capacity to finish bought in store lambs, except where overall stocking rates are constrained by insufficient ewe/suckler cow quota, or where catch crops are added to the rotation. 10. The addition of a store lamb enterprise to lowland systems was calculated to increase farm Gross MArgin by 2-3%, depending on the type of farm (dairy, stockless arable, or mixed). This represented a marginal return on capital invested in a store lamb finishing enterprise of 9-24%. 1. The financial risks involved, the availability of suitable labour and fixed equipment, and reluctance to vary arable rotations, make store lamb finishing enterprises less attractive to the lowland farmer. 12. Beyond the capacity to increase the number of certified lambs currently offered by up to 50%, greater opportunities are only likely to develop, when there is a significant increase in land (particularly on arable farms) entering conversion

Genetic interactions among floral homeotic genes of Arabidopsis

We describe allelic series for three loci, mutations in which result in homeotic conversions in two adjacent whorls in the Arabidopsis thaliana flower. Both the structure of the mature flower and its development from the initial primordium are described by scanning electron microscopy. New mutations at the APETALA2 locus, ap2-2, ap2-8 and ap2-9, cause homeotic conversions in the outer two whorls: sepals to carpels (or leaves) and petals to stamens. Two new mutations of PISTILLATA, pi-2 and pi-3, cause second and third whorl organs to differentiate incorrectly. Homeotic conversions are petals to sepals and stamens to carpels, a pattern similar to that previously described for the apetala3-1 mutation. The AGAMOUS mutations, ag-2 and ag-3, affect the third and fourth whorls and cause petals to develop instead of stamens and another flower to arise in place of the gynoecium. In addition to homeotic changes, mutations at the APETALA2, APETALA3 and PISTILLATA loci may lead to reduced numbers of organs, or even their absence, in specific whorls. The bud and flower phenotypes of doubly and triply mutant strains, constructed with these and previously described alleles, are also described. Based on these results, a model is proposed that suggests that the products of these homeotic genes are each active in fields occupying two adjacent whorls, AP2 in the two outer whorls, PI and AP3 in whorls two and three, and AG in the two inner whorls. In combination, therefore, the gene products in these three concentric, overlapping fields specify the four types of organs in the wild-type flower. Further, the phenotypes of multiple mutant lines indicate that the wild-type products of the AGAMOUS and APETALA2 genes interact antagonistically. AP2 seems to keep the AG gene inactive in the two outer whorls while the converse is likely in the two inner whorls. This field model successfully predicts the phenotypes of all the singly, doubly and triply mutant flowers described

Rethinking Manner and Form: From Parliamentary Sovereignty to Constitutional Values

The issue of whether a legislative body in a democratic society can bind itself on matters relating to the procedures by which the legislation is to be enacted, amended or repealed has, to this point, tended to dissolve into the question of which of two contending formulations of the doctrine of parliamentary sovereignty one prefers, Dicey\u27s traditional formulation or the new view by Jennings and others. The author argues that, regardless of how one formulates it, the doctrine of parliamentary sovereignty provides an unsound basis upon which to resolve this issue, and that an alternative basis is therefore needed. That alternative basis, he contends, flows from the recognition that the courts are the ultimate arbiters of what the law is in a given society, and that, in this context, the power to determine what the law is carries with it the power to determine to a significant degree how it is that the society will govern itself. For this reason, the courts must ensure that in making such determinations, they take their guidance from, and give expression to, the values of the legal and political culture of that society. These values will include, but will not be limited to, the values reflected in the doctrine of parliamentary sovereignty

From youth protection to individual responsibility: addressing smoking among young people in post-war West Germany

This article draws on health education material produced on smoking in the 1950s and 1960s in West Germany to question the extent to which smoking and health disappeared from the agenda in the post war decades, following the experience of the anti-smoking propaganda of the Third Reich. The article suggests that continuities can be seen in anti-smoking literature and campaigns both before and after the Third Reich around the notion of youth protection. In the 1960s, there was a more decisive break with the past with the foundation of the Ministry of Health and a growing determination to make health education a federal responsibility. There is an evident shift towards notions of individual responsibility and rational choice, informed by a growing body of international epidemiological evidence on smoking and health. There were also some attempts to engage with youth culture in the 1960s, rather than seeing youth culture as a threat to the social order, as had been the case in older youth protection arguments against smoking

Rethinking Manner and Form: From Parliamentary Sovereignty to Constitutional Values

The issue of whether a legislative body in a democratic society can bind itself on matters relating to the procedures by which the legislation is to be enacted, amended or repealed has, to this point, tended to dissolve into the question of which of two contending formulations of the doctrine of parliamentary sovereignty one prefers, Dicey\u27s traditional formulation or the new view by Jennings and others. The author argues that, regardless of how one formulates it, the doctrine of parliamentary sovereignty provides an unsound basis upon which to resolve this issue, and that an alternative basis is therefore needed. That alternative basis, he contends, flows from the recognition that the courts are the ultimate arbiters of what the law is in a given society, and that, in this context, the power to determine what the law is carries with it the power to determine to a significant degree how it is that the society will govern itself. For this reason, the courts must ensure that in making such determinations, they take their guidance from, and give expression to, the values of the legal and political culture of that society. These values will include, but will not be limited to, the values reflected in the doctrine of parliamentary sovereignty