1,721,209 research outputs found
Penfield's stimulation for direct cortical motor mapping: An outdated technique?
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Decomposition theorems for the K-theory of algebraic stacks
Full text linkA. Vistoli proved a decomposition theorem for the rational equivariant algebraic K-theory of a variety under the action of a finite group G. Subsequently, G. Vezzosi and A. Vistoli proved a decomposition theorem for the equivariant K-theory of a noetherian scheme, in the more general case where G is any affine algebraic group (with some mild hypothesis about the action). Moreover, B. Toen defined a Riemann-Roch map from the rational algebraic K-theory of a tame Deligne-Mumford quotient stack to the étale K-theory of its inertia. He proved that this map is an isomorphism and that it is covariant with respect to proper maps.In this thesis we first give a geometric definition of the Vezzosi-Vistoli decomposition, interpreting the pieces as corresponding to the components of the cyclotomic inertia. When the map from the cyclotomic inertia to the stack is finite, we can define a Riemann-Roch map in Toen's style. We prove that this map is an isomorphism and it is covariant with respect to proper relatively tame maps; moreover in some favourable circumstances we explicitly compute its inverse map, and show that we can recover Toen's one when the stack is tame Deligne-Mumford. Then we generalize Vistoli's result to more general algebraic (co)homology theories having the Mackey property and admitting localization long exact sequences. In general, the pieces are indexed by conjugacy classes of subgroups of G. Our construction is based on some result about a decomposition of the rational Burnside ring of a finite group, which stands behind the classical splitting theorems for equivariant spectra in stable equivariant homotopy theory. Applying this result to the case of Borne's modular K-theory we exhibit a case where the splitting is indexed by not necessarily abelian subgroups
Intraoperative neurophysiology in pediatric neurosurgery: a historical perspective
Full text linkIntroduction: Intraoperative neurophysiology (ION) has been established over the past three decades as a valuable discipline to improve the safety of neurosurgical procedures with the main goal of reducing neurological morbidity. Neurosurgeons have substantially contributed to the development of this field not only by implementing the use and refinement of ION in the operating room but also by introducing novel techniques for both mapping and monitoring of neural pathways. Methods: This review provides a personal perspective on the evolution of ION in a variety of pediatric neurosurgical procedures: from brain tumor to brainstem surgery, from spinal cord tumor to tethered cord surgery. Results and discussion: The contribution of pediatric neurosurgeons is highlighted showing how our discipline has played a crucial role in promoting ION at the turn of the century. Finally, a view on novel ION techniques and their potential implications for pediatric neurosurgery will provide insights into the future of ION, further supporting the view of a functional, rather than merely anatomical, approach to pediatric neurosurgery
A spotlight on intraoperative neurophysiological monitoring of the lower brainstem
No full textEditorial. A spotlight on intraoperative neurophysiological monitoring of the lower brainste
Some topics in the geometry of framed sheaves and their moduli spaces
Full text linkThis dissertation is primarily concerned with the study of framed sheaves on nonsingular projective varieties and the geometrical properties of the moduli spaces of these objects. In particular, we deal with a generalization to the framed case of known results for (semi)stable torsion free sheaves, such as (relative) Harder-Narasimhan filtration,
Mehta-Ramanathan restriction theorems, Uhlenbeck-Donaldson compactification, Atiyah class and Kodaira-Spencer map. The main motivations for the study of these moduli spaces come from physics, in particular, gauge theory, as we shall explain in the following
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