Search results for "Walker"
showing 10 items of 30 documents
Probing the creatable character of some significant universe models
2008
An unambiguous physical definition of creatable universes was recently proposed. According to it, flat and closed Friedmann-Robertson-Walker (FRW) backgrounds can be created as quantum vacuum fluctuations, whereas open backgrounds are not creatable. Here, physically motivated perturbations of closed and flat backgrounds are analyzed. Various creatable perturbed FRW universes are thus found. Some of them involve scalar and tensor perturbations with appropriate spectra, whereas other ones are Bianchi models.
18F-Radiolabeling, Preliminary Evaluation of Folate-pHPMA Conjugates via PET
2014
The synthesis of a 10.5 kDa and a 52.5 kDa polymer, based on pHPMA functionalized with tyramine for (18) F-labeling and a folate derivative as targeting moiety, is reported. FCS studies are conducted using Oregon Green-labeled conjugates. No aggregation is observed for the 10.5 kDa conjugate, but strong aggregation for the 52.5 kDa conjugate. In vivo studies are conducted using Walker-256 mammary carcinoma model to determine body distribution as function of size and especially targeting unit. These in vivo studies show a higher short time (2 h) accumulation for both conjugates in the tumor than for untargeted pHPMA, confirmed by blockade studies. The 10.5 kDa polymer accumulates with 0.46% …
A fully automatic approach for multimodal PET and MR image segmentation in gamma knife treatment planning
2017
The aim of this study is to combine Biological Target Volume (BTV) segmentation and Gross Target Volume (GTV) segmentation in stereotactic neurosurgery.Our goal is to enhance Clinical Target Volume (CTV) definition, including metabolic and morphologic information, for treatment planning and patient follow-up.We propose a fully automatic approach for multimodal PET and MR image segmentation. This method is based on the Random Walker (RW) and Fuzzy C-Means clustering (FCM) algorithms. A total of 19 brain metastatic tumors, undergone stereotactic neuro-radiosurgery, were retrospectively analyzed. A framework for the evaluation of multimodal PET/MRI segmentation is presented, considering volume…
Il ritorno alla fotografia: cultura visuale dall’analogico al digitale
2018
La fotografia ha svolto un ruolo fondamentale per l’affermazione e la definizione della cultura visuale: nei primi anni del Novecento essa ha posto le basi per il suo sviluppo; oggi che quella prospettiva sembra essere in crisi per l’avvento del digitale è utile ritornare a quegli anni per comprendere il presente. Accanto alle riflessioni di Walter Benjamin e László Moholy-Nagy, è stata fondamentale l’attività di Franz Roh, che trova un esaustivo compimento teorico nel breve testo foto-auge (1929): al di là delle felici intuizioni e delle feconde proposte che emergono in questo scritto, è degno di nota che esso diventa l’esempio privilegiato cui far riferimento anche dall’altra sponda dell’…
Optimal Resource Discovery Paths of Gnutella2
2008
This paper shows that the performance of peer-to-peer resource discovery algorithms is upper bounded by a k-Steiner minimum tree and proposes an algorithm locating near-optimal query paths for the peer-to-peer resource discovery problem. Global knowledge of the topology and the resources from the peer-to-peer network are required as an input to the algorithm. The algorithm provides an objective measure for defining how good local search algorithms are. The performance is evaluated in simulated peer-to-peer scenarios and in the measured Gnutella2 P2P network topology with four local search algorithms: breadth-first search, self-avoiding random walker, highest degree search and Dynamic Query …
Thermodynamic class II Szekeres-Szafron solutions. Singular models
2019
A family of parabolic Szekeres-Szafron class II solutions in local thermal equilibrium is studied and their associated thermodynamics are obtained. The subfamily with the hydrodynamic behavior of a generic ideal gas (defined by the equation of state $p = k n \Theta$) results to be an inhomogeneous generalization of flat FLRW $\gamma$-law models. Three significative interpretations that follow on from the choice of three specific thermodynamic schemes are analyzed in depth. First, the generic ideal gas in local thermal equilibrium; this interpretation leads to an inhomogeneous temperature $\Theta$. Second, the thermodynamics with homogeneous temperature considered by Lima and Tiomno (CQG 6 1…
Toiminnallinen identiteetti käsiteanalyysi Walkerin ja Avantin mukaan
2009
Cartographie de la pollution lumineuse zénithale en Bourgogne à partir de données de population et d'occupation du sol
2007
L'étude a pour but de fournir une première cartographie très simple de la pollution lumineuse sous SIG afin de faciliter l'interprétation géographique et, par la suite, la mise en relation avec d'autres facteurs. Bien sûr, un passage vers un modèle prédictif devient nécessaire si l'outil se destine à être une aide décisionnelle ou un outil de recherche ayant pour but d'analyser les conséquences des changements de certains de ses paramètres. Ainsi, un tel modèle pourra servir à évaluer et analyser les conséquences de la pollution lumineuse générée par la construction d'un nouveau quartier résidentiel, d'une zone indus‐ trielle, de nouvelles infrastructures routières.
Baltic Journal of English Language, Literature and Culture, Volume 9
2019
Contre la fausse objectivité, le perspectivisme assumé ? le reportage « gonzo » de Goldin, Clark, D’Agata, Tillmans contre la photographie « document…
2019
International audience; Après 1945, un certain nombre de praticiens de la « photographie plasticienne »privilégièrent le reportage « communautaire » : une plongée, sur le long terme, au sein d’ungroupe d’individus, souvent connus, voire intimes, du photographe, qui loin de se placercomme un témoin neutre, activait le mécanisme de l’observation participante chère àl’ethnographie. Larry Clark en fournit un exemple avec la série Tulsa (1971), la premièred’une longue lignée. Nan Goldin amplifia d’autant l’inclusion de l’autrice par la pratique del’autoportrait en situation dans The Ballad of Sexual Dependency (1981-1996). Plus tard desartistes comme Antoine d’Agata ou Wolfgang Tillmans poursuiv…