957 research outputs found
Security Policies as Membranes in Systems for Global Computing
We propose a simple global computing framework, whose main concern is code migration. Systems are structured in sites, and each site is divided into two parts: a computing body, and a membrane which regulates the interactions between the computing body and the external environment. More precisely, membranes are filters which control access to the associated site, and they also rely on the well-established notion of trust between sites. We develop a basic theory to express and enforce security policies via membranes. Initially, these only control the actions incoming agents intend to perform locally. We then adapt the basic theory to encompass more sophisticated policies, where the number of actions an agent wants to perform, and also their order, are considered
1.3 kg bolometers to search for rare events
Abstract Two TeO 2 crystal bolometers of 1.3 kg each, the largest single crystals ever operated with this technique, have been successfully realized and tested below 10 mK, in a dilution refrigerator located deep underground in the Gran Sasso National Laboratories. The calibration spectrum, obtained using an external 232Th γ -ray source, shows an energy resolution of 3–4 keV FWHM from 0.5 to 2.6 MeV, for both detectors. In the α region, a 4.3 keV FWHM resolution has been observed on the 5407 keV peak due to the α decay of 210Po, a natural contaminant of TeO 2 crystals
Robustness of a bisimulation-type faster-than preorder
TACS is an extension of CCS where upper time bounds for delays can be
specified. Luettgen and Vogler defined three variants of bismulation-type
faster-than relations and showed that they all three lead to the same preorder,
demonstrating the robustness of their approach. In the present paper, the
operational semantics of TACS is extended; it is shown that two of the variants
still give the same preorder as before, underlining robustness. An explanation
is given why this result fails for the third variant. It is also shown that
another variant, which mixes old and new operational semantics, can lead to
smaller relations that prove the same preorder.Comment: Express Worksho
Miniaturized NIR Spectrometers in a Nutshell: Shining Light over Sources of Variance
The increasing portability and accessibility of miniaturized NIR spectrometers are promoting the spread of in-field and online applications. Alongside the successful outcomes, there are also several problems related to the acquisition strategies for each instrument and to experimental factors that can influence the collected signals. An insightful investigation of such factors is necessary and could lead to advancements in experimental set-up and data modelling. This work aimed to identify variation sources when using miniaturized NIR sensors and to propose a methodology to investigate such sources based on a multivariate method (ANOVA-Simultaneous Component Analysis) that considers the effects and interactions between them. Five different spectrometers were chosen for their different spectroscopic range and technical characteristics, and samples of worldwide interest were chosen as the case study. Comparing various portable sensors is interesting since results could significantly vary in the same application, justifying the idea that this kind of spectrometer is not to be treated as a general class of instruments
Scintillating double beta decay bolometers
We present the results obtained in the development of scintillating Double
Beta Decay bolometers. Several Mo and Cd based crystals were tested with the
bolometric technique. The scintillation light was measured through a second
independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time
measurement. Thanks to the scintillation light, the alpha background is easily
discriminated resulting in zero counts above the 2615 keV gamma line of
Thallium 208. These results, combined with an extremely easy light detector
operation, represent the first tangible proof demonstrating the feasibility of
this kind of technique.Comment: 15 pages, 8 figure
EvaluaciĂłn de semen equino refrigerado con 3 diluyentes alternativos
Las funciones del plasma seminal son mantener la viabilidad espermática, proveer un medio Ăłptimo para el traslado y fecundaciĂłn de los espermatozoides en el tracto reproductor de la hembra. La refrigeraciĂłn implica un riesgo en la sobrevida de los espermatozoides; para preservarlos durante perĂodos prolongados, su actividad metabĂłlica debe ser reducida mediante la diluciĂłn en un medio apropiado y la reducciĂłn de la temperatura. Los diluyentes utilizados pueden ser de origen comercial o realizados a partir de la fĂłrmula descripta por Kenney en EEUU (1975) a base de leche en polvo. Debida a la amplia gama de aditivos presentes en las leches en polvo de producciĂłn nacional es necesario evaluar si Ă©stos pueden tener efectos favorables o no en el proceso de refrigeraciĂłn de semen equino, para poder ser usadas en su preservaciĂłn
Historical silk: a novel method to evaluate degumming with non-invasive infrared spectroscopy and spectral deconvolution
: To correctly manage a collection of historical silks, it is important to detect if the yarn has been originally subjected to degumming. This process is generally applied to eliminate sericin; the obtained fiber is named soft silk, in contrast with hard silk which is unprocessed. The distinction between hard and soft silk gives both historical information and useful indications for informed conservation. With this aim, 32 samples of silk textiles from traditional Japanese samurai armors (15th-20th century) were characterized in a non-invasive way. ATR-FTIR spectroscopy has been previously used to detect hard silk, but data interpretation is challenging. To overcome this difficulty, an innovative analytical protocol based on external reflection FTIR (ER-FTIR) spectroscopy was employed, coupled with spectral deconvolution and multivariate data analysis. The ER-FTIR technique is rapid, portable, and widely employed in the cultural heritage field, but rarely applied to the study of textiles. The ER-FTIR band assignment for silk was discussed for the first time. Then, the evaluation of the OH stretching signals allowed for a reliable distinction between hard and soft silk. Such an innovative point of view, which exploits a "weakness" of FTIR spectroscopy-the strong absorption from water molecules-to indirectly obtain the results, can have industrial applications too
The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the Next Decade. Highlights of the NuMass 2013 Workshop. Milano, Italy, February 4 - 7, 2013
The third Workshop of the NuMass series ("The Future of Neutrino Mass
Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the
Next Decade: NuMass 2013") was held at Dipartimento di Fisica "G. Occhialini,
University of Milano-Bicocca in Milano, Italy, on 4-7 February 2013. The goal
of this international workshop was to review the status and future of direct
and indirect neutrino mass measurements in the laboratory as well as from
astrophysical and cosmological observations. This paper collects most of the
contributions presented during the Workshop
The front-end readout for CUORICINO, an array of macro-bolometers and MIBETA, an array of ÎĽ-bolometers
The front-end approach for the readout of two arrays of bolometric detectors is described. The first front-end is for an array of m-bolometers, while the second is for an array of macro-bolometers. Analogies and differences in the adopted strategies are put into evidence
The Microcalorimeter Arrays for a Rhenium Experiment (MARE): a next-generation calorimetric neutrino mass experiment
Neutrino oscillation experiments have proved that neutrinos are massive
particles, but can't determine their absolute mass scale. Therefore the
neutrino mass is still an open question in elementary particle physics. An
international collaboration is growing around the project of Microcalorimeter
Arrays for a Rhenium Experiment (MARE) for directly measuring the neutrino mass
with a sensitivity of about 0.2eV/c2. Many groups are joining their experiences
and technical expertise in a common effort towards this challenging experiment.
We discuss the different scenarios and the impact of MARE as a complement of
KATRIN.Comment: 3 pages, 1 figure Nucl. Instr. Meth. A, proceedings of LTD11
workshop, Tokyo 200
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