36 research outputs found
Spin-density Wave in Ising-coupled Antiferromagnetic Chains
The effect of anisotropy in the nearest-neighbor spin interactions that
couple consecutive spin-1/2 antiferromagnetic chains is studied
theoretically by considering the limit where the coupling is purely of the
Ising type. An analysis based on the equivalent Luttinger model reveals that
the groundstate is an Ising antiferromagnet in general.Comment: 11 pgs. of plain TeX, one postscript fig., to appear in Phys. Rev.
Edge states and conformal boundary conditions in super spin chains and super sigma models
The sigma models on projective superspaces CP^{N+M-1|N} with topological
angle theta=pi mod 2pi flow to non-unitary, logarithmic conformal field
theories in the low-energy limit. In this paper, we determine the exact
spectrum of these theories for all open boundary conditions preserving the full
global symmetry of the model, generalizing recent work on the particular case
M=0 [C. Candu et al, JHEP02(2010)015]. In the sigma model setting, these
boundary conditions are associated with complex line bundles, and are labelled
by an integer, related with the exact value of theta. Our approach relies on a
spin chain regularization, where the boundary conditions now correspond to the
introduction of additional edge states. The exact values of the exponents then
follow from a lengthy algebraic analysis, a reformulation of the spin chain in
terms of crossing and non-crossing loops (represented as a certain subalgebra
of the Brauer algebra), and earlier results on the so-called one- and
two-boundary Temperley Lieb algebras (also known as blob algebras). A
remarkable result is that the exponents, in general, turn out to be irrational.
The case M=1 has direct applications to the spin quantum Hall effect, which
will be discussed in a sequel.Comment: 50 pages, 18 figure
Renal secondary hyperparathyroidism should be considered a differential diagnosis in forensic cases where animal abuse is suspected
This case description reports an adult dog with multiple rib fractures that was initially suspected to be the victim of non-accidental trauma, but eventually was diagnosed with severe chronic interstitial nephritis and renal secondary hyperparathyroidism leading to fibrous osteodystrophy and multiple pathological fractures. The importance of the specific expertise of a dedicated expert panel on animal abuse is discussed. This case illustrates the significance of the identification of normal, pathological, and breed-related variations within an animal in addition to forensic expertise, emphasizing that the presence of multidisciplinary teams in an expert panel on animal abuse is crucial
Renal secondary hyperparathyroidism should be considered a differential diagnosis in forensic cases where animal abuse is suspected
This case description reports an adult dog with multiple rib fractures that was initially suspected to be the victim of non-accidental trauma, but eventually was diagnosed with severe chronic interstitial nephritis and renal secondary hyperparathyroidism leading to fibrous osteodystrophy and multiple pathological fractures. The importance of the specific expertise of a dedicated expert panel on animal abuse is discussed. This case illustrates the significance of the identification of normal, pathological, and breed-related variations within an animal in addition to forensic expertise, emphasizing that the presence of multidisciplinary teams in an expert panel on animal abuse is crucial
Exploring subtle land use and land cover changes: a framework for future landscape studies
UMR AMAP, équipe 3International audienceLand cover and land use changes can have a wide variety of ecological effects, including significant impacts on soils and water quality. In rural areas, even subtle changes in farming practices can affect landscape features and functions, and consequently the environment. Fine-scale analyses have to be performed to better understand the land cover change processes. At the same time, models of land cover change have to be developed in order to anticipate where changes are more likely to occur next. Such predictive information is essential to propose and implement sustainable and efficient environmental policies. Future landscape studies can provide a framework to forecast how land use and land cover changes is likely to react differently to subtle changes. This paper proposes a four step framework to forecast landscape futures at fine scales by coupling scenarios and landscape modelling approaches. This methodology has been tested on two contrasting agricultural landscapes located in the United States and France, to identify possible landscape changes based on forecasting and backcasting agriculture intensification scenarios. Both examples demonstrate that relatively subtle land cover and land use changes can have a large impact on future landscapes. Results highlight how such subtle changes have to be considered in term of quantity, location, and frequency of land use and land cover to appropriately assess environmental impacts on water pollution (France) and soil erosion (US). The results highlight opportunities for improvements in landscape modelling
Absence of an effect of dietary fibre or clinoptilolite on boar taint in entire male pigs fed practical diets
This study aimed to evaluate the possibility of reducing boar taint in boars (Pietrain x Hybrid) by addition of different feed ingredients (raw potato starch (RPS) 10%, raw potato starch 10% + wheat bran 5% (RPS + WB), lupins 10%, inulin 5%, clinoptilolite 1%) to a standard diet over a period of 4-6 weeks before slaughter. Control boars (CBOAR) as well as barrows were fed the standard diet. Efficacy of the different feed ingredients was evaluated by different boar taint detection methods: hot iron method, consumer panel, expert panel and laboratory analysis. According to all detection methods, clear differences were noticeable between boars and barrows. No differences in boar taint incidence were found between the boars on the different dietary treatments as assessed by consumers, experts, hot iron method or the concentration of skatole in fat. A significant effect on indole level was found, but no further differentiation could be made. The concentration of backfat androstenone was significantly higher for the inulin and control boar group compared to the lupin group. In conclusion, none of the feeding strategies tested in this Study reduced boar taint in boars at the given percentages. All rights reserved