623 research outputs found
Local curvature-dimension condition implies measure-contraction property
No full textAbstractWe prove that for non-branching metric measure spaces the local curvature condition CDloc(K,N) implies the global version of MCP(K,N). The curvature condition CD(K,N) introduced by the second author and also studied by Lott and Villani is the generalization to metric measure space of lower bounds on Ricci curvature together with upper bounds on the dimension. This paper is the following step of Bacher and Sturm (2010) [1] where it is shown that CDloc(K,N) is equivalent to a global condition CD⁎(K,N), slightly weaker than the usual CD(K,N). It is worth pointing out that our result implies sharp Bishop–Gromov volume growth inequality and sharp Poincaré inequality
UWB orthogonal pulse design using Sturm–Liouville boundary value problem
No full textThe problem of designing UWB pulses which meet specific spectrum requirements is usually treated by filtering common pulses such as Gaussian doublets, modified Hermite polynomials and wavelets. When there is the need to have a number of orthogonal pulses (e.g., in a multiuser scenario), a naive approach is to filter all the members of an orthogonal set, which is likely to destroy their orthogonality property. In this paper, we study the design of a set of pulses that simultaneously satisfy the orthogonality property and spectrum requirements. Our design is based on the eigenfunctions of Sturm–Liouville boundary value problems. Indeed, we introduce Sturm–Liouville differential equations for which the eigenfunctions meet the FCC mask constraints. Computer simulation results show that all such waveforms occupy almost 55% of the allowed spectrum (utilization efficiency). A comparison of the proposed method with some conventional techniques of orthogonal UWB pulse generation will demonstrate the advantages of the new proposal.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De Schutte
Literale Grundkompetenzen und Medien in der Erwachsenenbildung. Ergebnisse des Projekts Illettrismus und neue Technologien
No full textEfficiency of 48h vs. 24h Injection of Parathyroid Hormone for Amelioration of Osteopenic Spine Properties in Male Rats
No full textDaily application of parathyroid hormone (PTH 1-34) is used for treatment of osteoporosis. It was investigated whether orchiectomy-induced osteoporotic changes in spine can be ameliorated by every 48h administration of PTH in aged male rats. Eight-month-old male Sprague-Dawley rats were sham operated (n=24) or orchiectomized (Orx, n=36) and maintained untreated over 12 weeks. Thereafter, both tibia underwent transverse metaphyseal osteotomy (Komrakova et al. 2011, J Endocrinol; 209:9-19) and rats were divided into 5 groups treated s.c. as follows: 1) sham vehicle; 2) sham PTH every 24h (PTH/24h); 3) Orx vehicle; 4) Orx PTH/24h; 5) Orx PTH every 48h (PTH/48h). PTH dosage was 40 g/kg BW per injection. After 5 weeks, lumbar vertebral bodies were used in computed tomographical, biomechanical, histomorphological, ashing and gene expression analyses. Cortical and trabecular densities, biomechanical properties, serum osteocalcin level increased significantly after PTH treatments in all groups (yield load, sham: 232+17N, sham PTH/24h: 376+12N, Orx: 239+16N, Orx PTH/24h: 324+31N, Orx PTH/48h: 297+17N). Bone inorganic weight enhanced after daily PTH application in Orx rats. Bone gene expression did not differ (P>0.05) among the groups. Both PTH administration regimes (24h and 48h) improved impaired bone structure in osteopenic rats. Every 48h application was less effective, however, it improved bone properties to the level observed in healthy (sham) rats. Considering limitation of daily treatments known in humans, these results may be useful for further clinical studies
Sturm-Picone type theorems for second order nonlinear impulsive differential equations
No full textWe obtain Sturm Picone type comparison theorems for nonlinear impulsive differential equations. Our results cover the previous results existing in the literature and useful in investigating qualitative behaviour of solutions of such equations
Recommended from our members
"Set Sail for the Sun", from "Aus den Sieben Tagen" by Karlheinz Stockhausen
No full textPerformance by Grey Area: Emma Lloyd, Owen Green, Armin Sturm, Sean Williams
Analysis of a Sturm–Liouville Problem Arising in Atmosphere
No full textWe present recent results in study of a mathematical model of the sea-breeze flow, arising from a general model of the ’morning glory’ phenomena. Based on analysis of the Dirichlet spectrum of the corresponding Sturm–Liouville problem and application of the Fredholm alternative, we establish conditions of existence/uniqueness of solutions to the given problem.Mathematical Physic
Sturm-Liouville Boundary Value Problem for a Sea-Breeze Flow
No full textWe present recent results in study of a mathematical model of the Sea-Breeze flow, arising from a general model of the ‘morning glory’ phenomena. Based on analysis of the Dirichlet spectrum of a corresponding Sturm-Liouville problem and application of the Fredholm alternative, we establish conditions of existence/uniqueness of solutions to the given problem.Mathematical Physic
Existence of solutions of higher order Sturm-Liouville boundary value problems
No full textWe consider a higher order Sturm-Liouville boundary value problem (BVP) where the nonlinear term involves derivatives – such cases are seldom investigated in the literature due to the complexity introduced by the derivatives. A new technique is used to obtain existence criteria for at least one positive solution of the BVP. We demonstrate the usefulness of the results obtained by an example with known positive solutions.Published versio
- …
