| 1. |
- Schael, S., et al.
(författare)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Forskningsöversikt (refereegranskat)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- de Graauw, Th., et al.
(författare)
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The Herschel-Heterodyne Instrument for the Far-Infrared (HIFI)
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518, s. L6-
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Tidskriftsartikel (refereegranskat)abstract
- Aims: This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI) that was launched onboard ESA's Herschel Space Observatory in May 2009. Methods: The instrument is a set of 7 heterodyne receivers that are electronically tuneable, covering 480-1250 GHz with SIS mixers and the 1410-1910 GHz range with hot electron bolometer (HEB) mixers. The local oscillator (LO) subsystem comprises a Ka-band synthesizer followed by 14 chains of frequency multipliers and 2 chains for each frequency band. A pair of auto-correlators and a pair of acousto-optical spectrometers process the two IF signals from the dual-polarization, single-pixel front-ends to provide instantaneous frequency coverage of 2 × 4 GHz, with a set of resolutions (125 kHz to 1 MHz) that are better than 0.1 km s-1. Results: After a successful qualification and a pre-launch TB/TV test program, the flight instrument is now in-orbit and completed successfully the commissioning and performance verification phase. The in-orbit performance of the receivers matches the pre-launch sensitivities. We also report on the in-orbit performance of the receivers and some first results of HIFI's operations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
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| 3. |
- Martinelli, E, et al.
(författare)
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Odor Processing with an experimental model of Olfactory epithelium and bulb
- 2011
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Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 36:1, s. E4-E4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Artificial olfaction was introduced as a model tool to investigateolfaction properties [1]. Nonetheless, the only analogy between the natural and the artificial system lies just in the selectivity proper- ties of the receptors. The implementation of more sophisticated fea- tures such as the large number of receptors and the glomerular layer have been hampered by technical difficulties related to the manage- ment of large numbers of simultaneous signals.As demonstrated in the past, optical imaging is a read-out tech- nique for sensors development that can provide large sensor arrays [2]. On that basis, we recently introduced an artificial olfaction sys- tem based on the imaging of a continuous layer of chemical indi- cators [3]. In this situation an image sensor provides a segmentation of the whole sensing layer in a number of elementary units corre- sponding to the pixels of the image. Eventually, since it is possible to evaluate the optical properties of every single pixel, each pixel of the image may correspond to an individual sensor. In this regard, even low-resolution images may easily result in thousands of independ- ent sensing units.In our system a collection of arbitrarily shaped regions of color indicators is illuminated by a controlled light source; the optical characteristics of each pixel of the image are measured by a camera yielding the light intensities in the three channels red, green, and blue. The combination of illumination sequence and cameraread-out results in a fingerprint encoding the optical properties of the sensing layer portioned in image pixels. Even a simple clas- sification of these fingerprints assigns each pixel to a class, and each class contains pixels carrying the same color indicator. This behav- ior resembles the association between ORNs carrying the same chemical receptors into the same glomerulus [4]. On the basis of this analogy it is straightforward to describe the layer of indicators as an artificial epithelium, pixels of the image as artificial olfactory neu- rons, and the classes provided by the classifier as an abstract rep- resentation of artificial glomeruli.This system thus allows the generation of a complex model of olfaction, including glomerular compartmentalization [5], which is then applied to data generated by the exposure to pure and mixed gases. Results show that such a model enhances the discrimination of pure and mixed odors. Eventually, such a platform, apart from evidencing the similarities between natural and artificial olfactory systems, is also proposed as a practical tool to test olfactory models.1. K. Persaud and G. Dodds, Nature 299 (1982) 3522. Dickinson et al., Nature 382 (1996) 6973. C. Di Natale et al., PLoS ONE 3 (2008) 31394. P. Mombaerts, Annu Rev Neurosci 22 (1999) 4875. D. Schild and H. Riedel, Biophysical Journal, 61 (1992) 704
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| 4. |
- Polese, D, et al.
(författare)
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Sharing data processing among replicated optical sensor arrays
- 2013
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 179:SI, s. 252-258
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Tidskriftsartikel (refereegranskat)abstract
- Sensor networks prompt a great deal of research interest within the computer and analytical sciences. To this regard, one of the most important issues is concerned with the interpretation of data that are collected by different sensors. Due to sensors non-reproducibility, this problem may also persist even when many replicas of the same sensors are considered. In this case additional calibrations may be required to use a common knowledge database. Noteworthy, the same problem arises in case of sensors replacement. In this paper we demonstrate that in case of optical chemical sensors drawing inspiration from the connectivity strategy of the olfactory bulb, this problem can find a straightforward solution when an image sensor is used to measure the optical properties of an extended sensing layer. If the sensing layer is formed by a number of spots of different indicators, it is demonstrated that a common data processing can be applied to any replica of the sensing layer even if the indicators are spotted with different geometries and in different quantities.
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| 5. |
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