129 research outputs found
Algebras of infinitesimal CR automorphisms
No full textThis paper is devoted to the investigation of Lie algebras of local infinitesimal CR automorphisms. Such algebras are naturally associated to germs of homogeneous CR manifolds. The authors introduce a corresponding abstract notion of CR algebra. A CR algebra is a pair (L,L1), consisting of a real Lie algebra L and a subalgebra L1 of the complexification C⊗RL, such that the factor space L/L∩L1 is finite-dimensional.
The authors investigate some formal properties of CR algebras and construct some "fibrations'' (i.e., L-equivariant submersions) of such algebras. They introduce three new notions of nondegeneracy of CR algebras---strict, weak and ideal nondegeneracy. These three concepts are weaker than those used previously by some other authors. The authors intend to extend the application of the É. Cartan method of investigating the equivalence of CR structures to some larger classes of CR manifolds.
One of the main ideas of this paper is a decomposition of arbitrary CR algebras into three "parts'': totally real, totally complex and weakly nondegenerate CR algebras (Theorems 5.3 and 5.4). There are some results about these three special classes of CR algebras. Some results about prolongations for transitive CR algebras are also obtained, in particular about maximality of parabolic CR algebras with respect to transitive prolongations
Complete nondegenerate locally standard CR manifolds
No full textLet M be a complete nondegenerate locally standard C R manifold. We show that a necessary and sufficient condition for M to be compact is that the Lie algebra of its infinitesimal CR automorphisms is semisimple. In general we realize M as a Mostow fibration over a compact CR manifold B whose universal covering is a Cartesian product of Hermitian symmetric spaces and compact nondegenerate standard CR manifolds
On non-pure forms on almost complex manifolds
No full textIn 2009 T.-J. Li and W. Zhang defined an almost complex structure J on a manifold X to be C^\infty-pure-and-full if the second de Rham cohomology group can be decomposed as a direct sum of the subgroups whose elements are cohomology classes admitting J-invariant and J-anti-invariant representatives. It turns out (see T. Draghici, T.-J. Li and W. Zhang (2010)) that any almost complex structure on a 4-dimensional compact manifold is C^\infty-pure-and-full. We study the J-invariant and J-anti-invariant cohomology subgroups on almost complex manifolds, possibly non-compact. In particular, we prove an analytic continuation result for anti-invariant forms on almost complex manifolds. - See more at: http://www.ams.org/journals/proc/2014-142-11/S0002-9939-2014-11578-4/#sthash.yZn8gAfE.dpu
Families of Almost Complex Structures and Transverse (p, p)-Forms
No full textAnalmost p-Kahler manifold is a triple (M, J, Omega), where (M, J) is an almost complex manifold of real dimension 2n and Omega is a closed real transverse (p, p)-form on (M, J), where 1 <= p <= n. When J is integrable, almost p-Kahler manifolds are called p-Kahler manifolds. We produce families of almost p-Kahler structures (J(t), Omega(t)) on C-3, C-4, and on the real torus T-6, arising as deformations of Kahler structures (J(0), g(0), omega(0)), such that the almost complex structures Jt cannot be locally compatible with any symplectic form for t not equal 0. Furthermore, examples of special compact nilmanifolds with and without almost p-Kahler structures are presented
Root involutions, real forms and diagrams
No full textWe study the correspondence between equivalence classes of pairs consisting of real semisimple Lie algebras and their Cartan subalgebras and involutions of the corresponding root system. This can be graphically described by introducing S- and Sigma- diagrams , generalizing those of Satake and Vogan. (c) 2024 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Experimental diabetic neuropathy: impairment of slow transport with changes in axon cross-sectional area.
No full textAnalysis of slow axonal transport in the sciatic and primary visual systems of rats with streptozotocin-induced diabetes of 4-6 weeks duration showed impairment of the transport of neurofilament subunits, tubulin, actin, and a 30- and a 60-kDa polypeptide in both systems. The degree of impairment was not uniform. Transport of polypeptide constituents of the slow component b, such as the 30- and 60-kDa polypeptides, appeared to be more severely affected than the transport of constituents of the slow component a, such as neurofilaments. Morphometric analysis of sciatic axons revealed a proximal increase and a distal decrease of axonal cross-sectional area. It is proposed that impairment of axoplasmic transport and changes of axonal size are related. Transport impairment results in a larger number of neurofilaments, microtubules, and other polypeptides in the proximal region of the axon, which increases in size, whereas fewer neurofilaments, microtubules, and other polypeptides reach the distal axons that show a size decrease. Such changes in axonal transport and area are likely to occur in other diabetic animal models and in human diabetes
Effects of age on the urinary excretion of total and non-dialyzable hydroxyproline
No full textThis study was carried out in order to investigate the effects of age on the urinary excretion of total and non-dialyzable hydroxyproline (OHPr) in normal subjects. We found that total urinary OHPr was negatively correlated with age but, by means of partial regression analysis, no correlation was found after correction for changes in creatinine clearance; on the contrary, non-dialyzable OHPr showed a statistically significant negative correlation with age (r=-0.56) even when creatinine clearance was held constant (p<0.05). A highly significant direct correlation was found between total and non-dialyzable OHPr in the whole group (r=0.54) and when only premenopausal women and men under 60 years of age were considered (r=0.51). No correlation was found when postmenopausal women and men more than 60 year-old were taken into account. Our data appear to indicate that also the decrease in osteogenetic activity is responsible for the physiological late involutional bone loss; they also show the importance of hormonal changes in inducing an uncoupling between bone formation and resorption. © 1984 Springer-Verlag
Long-term remission in schizophrenia and related psychoses with long-acting risperidone: results obtained in an open-label study with an observation period of 18 months.
No full textTo monitor long-term symptomatic tolerability and remission in patients with stable but sub-optimally treated psychoses after switching to risperidone long-acting injectable (RLAI).This subgroup analysis of the Switch to Risperidone Microspheres (StoRMi) open-label trial followed up patients with psychoses who were converted to RLAI for a period of 18 months or until RLAI became commercially available in their country of residence. It included patients from seven European countries. Dosage adjustments were performed as clinically necessary. The efficacy endpoint was achieving and maintaining remission, defined as absent to mild core schizophrenia symptoms for > or = 6 months. A schizophrenia assessment was also completed and patients were monitored for the development of adverse events (AEs). Discontinuation rates were calculated based on Kaplan-Meier estimates where patients switching to commercial RLAI were used as censored observations. A total of 529 patients were followed for up to 18 months. At 18 months, the discontinuation rate was 55.7% based on Kaplan-Meier estimates. The median time to discontinuation was 15.7 months (95% CI (14.0; 17.5)). RLAI was generally well tolerated with most AEs mild-to-moderate in severity. 13% of patients discontinued treatment because of an AE. Body weight of patients increased by a mean A+/- SD of 1.0 A+/- 6.1 kg from treatment initiation to endpoint (p = 0.0001). Glucose-related AEs occurred in four patients (0.8%). Among those patients not meeting severity remission criteria at baseline, 44.8% were in remission at endpoint. Among those patients meeting severity criteria for remission at baseline, 84.2% were in remission at endpoint. A total of 93.7% of the patients who achieved or maintained remission at 6 months were in remission at endpoint. RLAI is safe during long-term treatment up to 18 months in adults requiring antipsychotics. Conversion to RLAI resulted in improved symptom control. Most patients achieved and maintained a sustained remission (> or = 6 months) after conversion to RLAI
Efficacy and safety of risperidone long-acting injectable in stable psychotic patients previously treated with oral risperidone.
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