93,867 research outputs found
Sostenere le comunità nelle pratiche di innovazione place-based. Nuovi paradigmi per le pratiche di homemaking in un Villaggio Urbano Integrato per la cura della demenza.
No full textNell’ambito delle terapie non-farmacologiche per la cura della demenza, e dell’importanza che gli spazi rivestono per la loro efficacia, la ricerca presentata in questo paper descrive e identifica processi e dinamiche di homemaking, che portano alla co-creazione degli spazi interni di un ambiente di cura. Tali pratiche consentono alle persone con demenza e ai loro caregiver di stabilire un senso di appartenenza nei confronti dei nuovi spazi in cui vivono, all’interno di un Villaggio Urbano Integrato per la demenza, dove l’ambiente di cura non è più confinato all’interno di un perimetro sorvegliato, ma si sovrappone e si fonde con l’ambiente urbano esistente, consentendo agli ospiti di vivere una vita quotidiana normale e significativa, insieme alla comunità di cittadini che vive nel quartiere, in un’ottica di inclusività
Positronium cooling at cryogenic temperature for advanced experiments
No full textNew Ps spectroscopy measurements, formation of antihydrogen for antimatter-matter comparison experiments, production of Ps beams require the efficient production of cooled positronium in vacuum. At present the most efficient positron-positronium converters are silica based ordered or disordered porous materials, in which formed Ps decreases its kinetic energy by collisional cooling. Recently new positron-positronium converters based on oxidized nanochannels in silicon were found to be very promising because of the tunability of the nanochannel size, which allows to overcome the limits imposed to the Ps cooling by the quantum confinement. With these converters, Ps with temperatures as low as 150 K was detected in vacuum by a TOF apparatus. The Ps formation, quantum confinement, collisional cooling and emission into vacuum from nanochanneled silicon will be discussed in light of recent results. © Published under licence by IOP Publishing Ltd
Production of cold positronium atoms
No full textPositronium will play a primary role in the next generation of antimatter experiments through the following antihydrogen production reaction: (p) over bar + Ps* ->(p) over bare(+) + e(-). In order to study antimatter physical properties (CPT (charge, parity, time) invariance and principle of equivalence test) it is necessary to keep this system at the lowest possible (sub-kelvin) temperatures. This requires the generation of a suitable flux of cold Ps atoms in a vacuum, a non-trivial requirement at the light of the present experimental results. In this paper we discuss the state of the actual knowledge on positronium formation and consequent emission from metallic surfaces and insulators and we show the opportunity to use suitable porous materials to cool positronium through collisions with the inner walls of the pores. We get a rough indication on the geometrical parameters of the pore and we propose a simple experiment to obtain the kinetic energy - and therefore the equivalent temperature - of emitted positronium without using a positron beam
Time of Flight system to investigate positronium cooling
No full textA positronium Time of Flight (TOF) apparatus, conceived to work with continuous positron beams of intensity up to ∼10 6 positrons/s, was developed. The geometry of the TOF chamber and the acquisition chain are described in detail. The performances of the set up were preliminary tested with a laboratory positron beam of ∼5 × 10 3 positrons/s by measuring the Time of Flight of Ps emitted from oxidized nanochannels produced in a Si single crystal. A TOF spectrum of ∼10 4 events was collected in 9 days with a time resolution of 8 ns. The analysis of the TOF spectrum is discussed. This apparatus is going to be assembled at the intense positron source NEPOMUC at FRM-II reactor, where the measurement time of each spectrum will be reduced to less than 2 h, making this TOF system appropriate to investigate positronium emission after cooling in porous materials held at cryogenic temperature. © The Author(s) 2012
Structural Evolution and Medium Range Order in Permanently Densified Vitreous SiO2
No full textPositron annihilation lifetime spectroscopy is employed to measure the size of the interstitial void spaces characterizing the structure of a set of permanently densified SiO2 glasses. The average volume of the voids is markedly affected by the densification process and linearly shrinks by almost an order of magnitude after a relative density variation of 22%. In addition, x-ray diffraction shows that this change of density does not modify appreciably the short range order, which remains organized in SiO4 tetrahedra. These results strongly suggest a porous medium description for v-SiO2 glasses where the compressibility and the medium range order are dominated by the density variation of the voids volume up to densities close to that of alpha-quartz
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Amorphous carbon thin films deposited on Si and PET: study of interface states
No full textThin carbon films with various thicknesses, deposited on different substrates (Si and PET) at the same operating conditions in a radio frequency plasma enhanced chemical vapour deposition (RF-PECVD) system were characterized by Doppler Broadening Spectroscopy (DBS). The films and the substrates were depth profiled by a slow positron beam. The aim of these measurements was to study the open volume structure and the interface of the films. It was found that, independently from the substrate, the films were homogeneous and exhibeted the same open volume distribution. On the contrary, the effective positron diffusion length in the Si substrate was found to change with the thickness of the carbon films. This behaviour was interpreted as a change in the electric field at the carbon/silicon interfac
Author inscription in The Chinese slave-girl: a story of woman's life in China
No full textThis edition includes a gift inscription by author Rev. J.A. Davis, "To Rev. A. G. Russell with the warmest regards of the author J.A. Davis."Davis, John Agnell, 1839-1897
G-Rank: Unsupervised Continuous Learn-to-Rank for Edge Devices in a P2P Network
No full textRanking algorithms in traditional search engines are powered by enormous training data sets that are meticulously engineered and curated by a centralized entity. Decentralized peer-to-peer (p2p) networks such as torrenting applications and Web3 protocols deliberately eschew centralized databases and computational architectures when designing services and features. As such, robust search-and-rank algorithms designed for such domains must be engineered specifically for decentralized networks, and must be lightweight enough to operate on consumer-grade personal devices such as a smartphone or laptop computer. We introduce G-Rank, an unsupervised ranking algorithm designed exclusively for decentralized networks. We demonstrate that accurate, relevant ranking results can be achieved in fully decentralized networks without any centralized data aggregation, feature engineering, or model training. Furthermore, we show that such results are obtainable with minimal data preprocessing and computational overhead, and can still return highly relevant results even when a user’s device is disconnected from the network. G-Rank is highly modular in design, is not limited to categorical data, and can be implemented in a variety of domains with minimal modification. The results herein show that unsupervised ranking models designed for decentralized p2p networks are not only viable, but worthy of further research.https://github.com/awrgold/G-RankComputer Scienc
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