358 research outputs found
Extending Bauer's corollary to fractional derivatives
We comment on the method of Dreisigmeyer and Young [D. W. Dreisigmeyer and P.
M. Young, J. Phys. A \textbf{36}, 8297, (2003)] to model nonconservative
systems with fractional derivatives. It was previously hoped that using
fractional derivatives in an action would allow us to derive a single retarded
equation of motion using a variational principle. It is proven that, under
certain reasonable assumptions, the method of Dreisigmeyer and Young fails.Comment: Accepted Journal of Physics A at www.iop.org/EJ/journal/JPhys
Linear dichroism of CdSe nanodots: Large anisotropy of the band-gap absorption induced by ground-state dipole moments
We measured the electric field induced linear dichroism for a wide range of sizes of CdSe nanocrystals. Large ground-state dipole moments were observed, especially for the smallest crystals. In these, we found a very large anisotropy of the absorption and most of the dipole strength is along the direction of the ground-state dipole moment. For the anisotropy, we propose a mechanism for intensity borrowing from intraband transitions, induced by the field of the ground-state dipole moment. © 2008 The American Physical Society
Semantic-based policy engineering for autonomic systems
This paper presents some important directions in the use of ontology-based semantics in achieving the vision of Autonomic Communications. We examine the requirements of Autonomic Communication with a focus on the demanding needs of ubiquitous computing environments, with an emphasis on the requirements shared with Autonomic Computing. We observe that ontologies provide a strong mechanism for addressing the heterogeneity in user task requirements, managed resources, services and context. We then present two complimentary approaches that exploit ontology-based knowledge in support of autonomic communications: service-oriented models for policy engineering and dynamic semantic queries using content-based networks. The paper concludes with a discussion of the major research challenges such approaches raise
Finite formulation and domain-integrated field relations in electromagnetics - a synthesis
Ileal metastasis from thoracic melanoma disclosed by video capsule endoscopy: an unusual but not extraordinary source of obscure bleeding
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Nonconservative Lagrangian mechanics II: purely causal equations of motion
This work builds on the Volterra series formalism presented in [D. W.
Dreisigmeyer and P. M. Young, J. Phys. A \textbf{36}, 8297, (2003)] to model
nonconservative systems. Here we treat Lagrangians and actions as `time
dependent' Volterra series. We present a new family of kernels to be used in
these Volterra series that allow us to derive a single retarded equation of
motion using a variational principle
Utilizzo di sistemi GIS per lo studio della âtemporaneitĂ â nei territori post-sisma del Centro Italia
Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking
Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods
Strategie temporanee post-disastro nei territori fragili italiani
La sessione speciale si inscrive nell'ambito delle iniziative proposte dalla rete di giovani ricercatori "TEMP Una rete interdisciplinare e interuniversitaria che si propone di indagare, mediante un confronto ampio e molteplice, il tema della temporaneitaÌ post-emergenza nel territori fragili italiani nella sua complessitaÌ e multidimensionalitaÌ. Dunque, specifica attenzione eÌ rivolta al contesto italiano e tra le varie emergenze che connotano questi territori, si fa riferimento alle conseguenze determinate dal frequenti fenomeni sismici, eventi che hanno la forza di sovvertire dinamiche spaziali e territoriali consolidate. L'immediata risposta emergenziale allevento apre ad un intervallo temporale che concentra forze pubbliche, economiche e socio- culturali responsabili di nuove gerarchie di necessitaÌ, nuovi assetti territoriali e geografie instabili In questo contesto, il consolidato approccio settoriale all'emergenza -prima emergenza, secondo emergenza e ricostruzione-si dimostra sempre piuÌ inadatto a fronteggiare la complessitaÌ dell'attuale policrisi che vede inedite e molteplici interrelazioni e concatenazioni tra differenti rischi, catastrofi ed emergenze. CioÌ richiede continue azioni elastiche e preventive di pianificazione strategica che possano guidare la trasformazione nel lungo periodo
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