239 research outputs found
Generic singularities of symplectic and quasi-symplectic immersions
For any k<2n we construct a complete system of invariants in the problem of
classifying singularities of immersed k-dimensional submanifolds of a
symplectic 2n-manifold at a generic double point.Comment: 12 page
Comparative studies of compatible and incompatible pepper–Tobamovirus interactions and the evaluation of effects of 24-epibrassinolide
The aim of study was to gain a deeper knowledge about local and systemic changes in photosynthetic processes and sugar
production of pepper infected by
Obuda pepper virus
(ObPV) and
Pepper mild mottle virus
(PMMoV). PSII efficiency,
reflectance, and gas exchange were measured 48 and/or 72
h after inoculation (hpi).
Sugar accumulation was checked
72 hpi and 20 d after inoculation (as a systemic response). Inoculation of leaves with ObPV led to appearance of
hypersensitive necrotic lesions (incompatible interaction), while PMMoV caused no visible symptoms (compatible
interaction). ObPV (but
not PMMoV) lowered F
v
/F
m
(from 0.827 to 0.148 at 72 hpi). Net photosynthesis decreased in
ObPV-infected leaves. In ObPV-inoculated leaves, the accumulation of glucose, fructose, and glucose-6-phosphate was
accompanied with lowered sucrose, malt
oheptose, nystose, and trehalose cont
ents. PMMoV inoculation increased the
contents of glucose, maltose, and raffi
nose in the inoculated
leaves, while glucose-6-phos
phate accummulated in upper
leaves
Singularities of equidistants and global centre symmetry sets of Lagrangian submanifolds
We define the Global Centre Symmetry set (GCS) of a smooth closed
m-dimensional submanifold M of R^n, , which is an affinely invariant
generalization of the centre of a k-sphere in R^{k+1}. The GCS includes both
the centre symmetry set defined by Janeczko and the Wigner caustic defined by
Berry. We develop a new method for studying generic singularities of the GCS
which is suited to the case when M is lagrangian in R^{2m} with canonical
symplectic form. The definition of the GCS, which slightly generalizes one by
Giblin and Zakalyukin, is based on the notion of affine equidistants, so, we
first study singularities of affine equidistants of Lagrangian submanifolds,
classifying all the stable ones. Then, we classify the affine-Lagrangian stable
singularities of the GCS of Lagrangian submanifolds and show that, already for
smooth closed convex curves in R^2, many singularities of the GCS which are
affine stable are not affine-Lagrangian stable.Comment: 26 pages, 2 figure
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The role of beliefs, expectations and values in decision-making favoring climate change adaptation—implications for communications with European forest professionals
Beliefs, expectations and values are often assumed to drive decisions about climate change adaptation. We tested hypotheses based on this assumption using survey responses from 508 European forest professionals in ten countries. We used the survey results to identify communication needs and the decision strategies at play, and to develop guidelines on adequate communications about climate change adaptation. We observed polarization in the positive and negative values associated with climate change impacts accepted by survey respondents. We identified a mechanism creating the polarization that we call the 'blocked belief' effect. We found that polarized values did not correlate with decisions about climate change adaptation. Strong belief in the local impacts of climate change on the forest was, however, a prerequisite of decision-making favoring adaptation. Decision-making in favor of adaptation to climate change also correlated with net values of expected specific impacts on the forest and generally increased with the absolute value of these in the absence of 'tipping point' behavior. Tipping point behavior occurs when adaptation is not pursued in spite of the strongly negative or positive net value of expected climate change impacts. We observed negative and positive tipping point behavior, mainly in SW Europe and N-NE Europe, respectively. In addition we found that advice on effective adaptation may inhibit adaptation when the receiver is aware of effective adaptation measures unless it is balanced with information explaining how climate change leads to negative impacts. Forest professionals with weak expectations of impacts require communications on climate change and its impacts on forests before any advice on adaptation measures can be effective. We develop evidence-based guidelines on communications using a new methodology which includes Bayesian machine learning modeling of the equivalent of an expected utility function for the adaptation decision problem
X-ray fluorescence analysis of long-term changes in the levels and distributions of trace elements in the rat brain following mechanical injury
This paper describes the results of the application of X-ray fluorescence microscopy to the qualitative, topographic and quantitative elemental analysis of nervous tissue from rats with neocortical brain injury. The tissue samples were analyzed with a 15 μm beam defined by the size of the polycapillary focus. Raster scanning of the samples generated 2D cartographies, revealing the distributions of elements such as P, S, Cl, K, Ca, Fe, Cu, and Zn. Special emphasis was placed on the analysis of the areas neighboring the lesion site and the hippocampal formation tissue. The results obtained for rats with mechanical brain injuries were compared with those recorded for controls and animals with pilocarpine-induced seizures. There were no significant differences in the elemental compositions of gray and white matter between injured and uninjured brain hemispheres. A higher level of Ca was observed in the gray matter of both of the hemispheres in brains with neocortical injuries. A similar relation was noticed for Fe in the white matter. A comparative study of hippocampal formation tissue showed a statistically significant decrease in the mass per unit area of P in the dentate gyrus (DG) and the hilus (H) of DG for animals with brain lesions in comparison with the control group. Analogous relations were found for Cu in the DG and Zn in sector 3 of Ammon’s horn (CA3) and the DG. It is important to note that identical changes in the same areas were observed for animals with pilocarpine-induced seizures in our previous study
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