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- Nascimento, V. B., et al.
(författare)
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Surface-Stabilized Nonferromagnetic Ordering of a Layered Ferromagnetic Manganite
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 227201-
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Tidskriftsartikel (refereegranskat)abstract
- An outstanding question regarding the probing or possible device applications of correlated electronic materials (CEMs) with layered structure is the extent to which their bulk and surface properties differ or not. The broken translational symmetry at the surface can lead to distinct functionality due to the charge, lattice, orbital, and spin coupling. Here we report on the case of bilayered manganites with hole doping levels corresponding to bulk ferromagnetic order. We find that, although the hole doping level is measured to be the same as in the bulk, the surface layer is not ferromagnetic. Further, our low-energy electron diffraction and x-ray measurements show that there is a c-axis collapse in the outermost layer. Bulk theoretical calculations reveal that, even at fixed doping level, the relaxation of the Jahn-Teller distortion at the surface is consistent with the stabilization of an A-type antiferromagnetic state.
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| 3. |
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| 4. |
- Loader, N J, et al.
(författare)
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The role of inter-specific, micro-habitat and climatic factors on the carbon isotope (delta C-13) variability of a modern leaf assemblage from northern Scandinavia: implications for climate reconstruction
- 2006
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Ingår i: Boreas. - : Wiley. - 1502-3885 .- 0300-9483. ; 35:2, s. 188-201
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Tidskriftsartikel (refereegranskat)abstract
- To provide a basis for the interpretation of past climatic conditions from Quaternary leaf records, leaf carbon isotope (delta C-13) results are presented for 12 northern European dwarf-shrub, shrub and tree species growing across a network of 18 sites in northern Scandinavia. The role of micro-habitat (hummock/hollow) on carbon isotope trends is explored in addition to a comparison of the carbon isotope composition of both cellulose and wholeleaf material. The data are also examined against local meteorological variables (temperature, precipitation and vapour pressure deficit) at both species and genus levels. Results exhibit only modest coherence between selected plant species and low-order correlations with external climate forcings consistent with accepted models for carbon isotope fractionation. Potential for the analysis and interpretation of stable isotopic time series may still be identified; however, factors such as inter-plant variability, senescence, diagenesis and homogeneity need to be thoroughly addressed before such an approach may be used for palaeoenvironmental reconstructions. These findings highlight the complexities and limitations of spatial calibration methods.
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| 5. |
- Visser, E.K., et al.
(författare)
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Does Horse Temperament Influence Horse-Rider Cooperation?
- 2008
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Ingår i: Journal of Applied Animal Welfare Science. - : Informa UK Limited. - 1088-8705 .- 1532-7604. ; 11:3, s. 267-284
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Tidskriftsartikel (refereegranskat)abstract
- Cooperation between rider and horse is of major importance in equitation. A balanced team of horse and rider improves (sport) performances and welfare aspects by decreasing stress, frustration, risks of injuries, and accidents. Important features affecting the cooperation are the physical skills, knowledge, and personality of the rider on one hand and the temperament, experience, and physical abilities of the horse on the other. A study with 16 riders and 16 warm-blood riding horses tested the effect of personality of riders and temperament of horses on cooperation between riders and horses. More emotionally reactive horses showed more evasive behavior during riding. Riders preferred to ride those horses who were assessed by the riders as being attentive to the rider's aid. The frequency of evasive behaviors during riding - as assessed by riders, in contrast to the assessments made by an external judge - influenced the cooperation between rider and horse. On average, a rider's personality did not affect the cooperation between rider and horse; however, it is suggested that a rider's personality does affect the cooperation with more emotionally reactive horses.
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