542 research outputs found
The cosmic microwave background: observing directly the early universe
The Cosmic Microwave Background (CMB) is a relict of the early universe. Its
perfect 2.725K blackbody spectrum demonstrates that the universe underwent a
hot, ionized early phase; its anisotropy (about 80 \mu K rms) provides strong
evidence for the presence of photon-matter oscillations in the primeval plasma,
shaping the initial phase of the formation of structures; its polarization
state (about 3 \mu K rms), and in particular its rotational component (less
than 0.1 \mu K rms) might allow to study the inflation process in the very
early universe, and the physics of extremely high energies, impossible to reach
with accelerators. The CMB is observed by means of microwave and mm-wave
telescopes, and its measurements drove the development of ultra-sensitive
bolometric detectors, sophisticated modulators, and advanced cryogenic and
space technologies. Here we focus on the new frontiers of CMB research: the
precision measurements of its linear polarization state, at large and
intermediate angular scales, and the measurement of the inverse-Compton effect
of CMB photons crossing clusters of Galaxies. In this framework, we will
describe the formidable experimental challenges faced by ground-based,
near-space and space experiments, using large arrays of detectors. We will show
that sensitivity and mapping speed improvement obtained with these arrays must
be accompanied by a corresponding reduction of systematic effects (especially
for CMB polarimeters), and by improved knowledge of foreground emission, to
fully exploit the huge scientific potential of these missions.Comment: In press. Plenary talk. Copyright 2012 Society of Photo-Optical
Instrumentation Engineers. One print or electronic copy may be made for
personal use only. Systematic reproduction and distribution, duplication of
any material in this paper for a fee or for commercial purposes, or
modification of the content of the paper are prohibite
Cognitive Perspectives on English-Italian Spatial Particles: Towards a Motivated Description of Spatial and Non-Spatial Senses from the Lower Section of the Vertical Dimension
English and Italian differ a great deal in their respective repertoires of spatial particles (an important subset of which are prepositions), an area which seems to be quite problematic in foreign language learning. Most current EFL textbooks and didactic grammars tend to provide partial and idiosyncratic cross-linguistic descriptions of such items, while the majority of dictionaries' accounts are grounded in an alphabetical order. This article contributes to the field of research on Cognitive Linguistics applications to pedagogical grammar (see, e.g., Tyler and Evans 2004, Evans and Tyler 2005, Boers et al. (eds) 2010) by proposing a motivated, cognitively grounded contrastive account of particles in English and Italian which ideally addresses the needs of pedagogy professionals as well as of advanced Italian learners of English. The proposal draws on Tyler and Evans's (2003) Principled Polysemy Network model (also see Evans 2010) and applies the rationale of a cognitively oriented view of Lexical Complexity (Bertuccelli Papi and Lenci 2007) to the overall organisation of data. Spatial and non-spatial senses of particles of verticality are here focused on, especially those in the lower section of the vertical axis. The examples were mainly gathered from dictionaries, corpora and informants
Food across time and space: Pinocchio and its English translations
This article focuses on the study of food lexis in Le Avventure di Pinocchio. Storia di un Burattino (Collodi 1981/1883) and in seven of the workâs major British and American English translations published over a period of around 130 years. Pinocchio is a transnational classic of childrenâs literature that ideally addresses a dual audience (OâSullivan 1993, Lathey 2006). Food and hunger are often âevokedâ in the story (Belpoliti 2003 inter alia) and appear to perform two functions: 1) contribute to the portrayal of the Italian culture and society of the time, and 2) enhance childrenâs involvement through imagined perceptual experiences primarily (although not exclusively) based on taste and smell. In fact, preserving both functions in translation is quite difficult, as maintaining the culture-specific quality of the original entails placing less emphasis on young readersâ expectations in the target cultures, while assimilating original items to the target background inevitably involves variable loss of original details. The analysis displays different translation strategies at work in the various texts. More recent American versions, in particular, appear to be more open to foreign influences and contaminations, probably reflecting a higher degree of recognition and integration of originally foreign cuisine in a cosmopolitan setting
Humour in TED Talks: A multimodal account
TED talks represent a popular digital genre for the dissemination and popularisation of knowledge of multiple domains, and humour is one of its endemic characteristics. While past research has mainly focused on the linguistic expression of humour in the talks, the present contribution explores multimodal ensembles comprising visuals (i.e., slides with images and videos), words and gestures which jointly contribute to humour generation in various ways. The data come from a small corpus of talks from the domains of Technology, Economics and Law. The domain of Technology proves to be the richest in humorous episodes, some of which are illustrated through multimodal transcription and a detailed qualitative analysis. The latter leads to the identification of the causes for humour and its varied functions within the talks, which go beyond the management of interpersonal relations and sometimes intertwine with argumentation and strategies of popularisation for the development of the main topics of the talks. As humour understanding may be a particularly challenging task for an international audience such as the one addressed by TED speakers, a more comprehensive grasp of its dynamics may hopefully shed light on its subtleties, and on its engagement or captivating potential for ESP learners and EFL extramural contact
THE MULTIMODAL REPRESENTATION OF âIDEAS WORTH SPREADINGâ THROUGH TED TALKS
The slogan of TED talks reminds one of the overarching goal of this genre, i.e. to spread/share worthy ideas from different knowledge domains among the general public. The present contribution applies a multimodal perspective to the analysis of evaluation as a strategy used to shape such ideas in the talks. It actually takes into account a broad conception of evaluation as the expression of the speakerâs attitude or stance towards, viewpoint on, or feelings about what is being talked about (Thompson & Hunston, 2000), which, in this textual genre in particular, tends to be imbued with a strong desire to cause or evoke a similar experience in the audience. The study focuses on quantitative and qualitative data on subjective (emotional and axiological) adjectives, gestures and visuals (content of slides) combining in ever more complex multimodal ensembles from a selection of talks in three different domains, in order to gain a more comprehensive insight into tedstersâ representations of their views emerging from the interactions of such resources. In fact, the findings show that the latter contribute significantly to the shaping of the proposed ideas as something worth listening to (and, ideally, endorsing). Also, they appear to display varied combinations across knowledge domains, thus pointing towards domain variation as a possible constraining factor responsible for the diversification of the multimodal rhetoric associated with the genre
The multimodal representation of âIdeas worth spreadingâ through TED talks
The slogan of TED talks reminds one of the overarching goals of this genre, i.e. to spread/share worthy ideas from different knowledge domains among the general public. The present contribution applies a multimodal perspective to the analysis of evaluation as a strategy used to shape such ideas in the talks. It actually takes into account a broad conception of evaluation as the expression of the speakerâs attitude or stance towards, viewpoint on, or feelings about what is being talked about (Thompson, Hunston 2000), which, in this textual genre in particular, tends to be imbued with a strong desire to cause or evoke a similar experience in the audience. The study focuses on quantitative and qualitative data on subjective (emotional and axiological) adjectives, gestures and visuals (content of slides) combining in ever more complex multimodal ensembles from a selection of talks in three different domains, in order to gain a more comprehensive insight into tedstersâ representations of their views emerging from the interactions of such resources. In fact, the findings show that the latter contribute significantly to the shaping of the proposed ideas as something worth listening to (and, ideally, endorsing). Also, they appear to display varied combinations across knowledge domains, thus pointing towards domain variation as a possible constraining factor responsible for the diversification of the multimodal rhetoric associated with the genre.
Common-mode rejection in Martin-Puplett spectrometers for astronomical observations at mm-wavelengths
The Martin-Puplett interferometer (MPI) is a differential Fourier transform
spectrometer (FTS), measuring the difference between spectral brightness at two
input ports. This unique feature makes the MPI an optimal zero instrument, able
to detect small brightness gradients embeddend in a large common background. In
this paper we investigate experimentally the common-mode rejection achievable
in the MPI at mm wavelengths, and discuss the use of the instrument to measure
the spectrum of cosmic microwave background (CMB) anisotropy
Sensitivity to Cosmic Rays of Cold Electron Bolometers for Space Applications
An important phenomenon limiting the sensitivity of bolometric detectors for
future space missions is the interaction with cosmic rays. We tested the
sensitivity of Cold Electron Bolometers (CEBs) to ionizing radiation using
gamma-rays from a radioactive source and X-rays from a X-ray tube. We describe
the test setup and the results. As expected, due to the effective thermal
insulation of the sensing element and its negligible volume, we find that CEBs
are largely immune to this problem.Comment: LTD15; 6 pages, 6 figure
Optimization of the half wave plate configuration for the LSPE-SWIPE experiment
The search for the B-mode polarization of Cosmic Microwave Background (CMB)
is the new frontier of observational Cosmology. A B-mode detection would give
an ultimate confirmation to the existence of a primordial Gravitational Wave
(GW) background as predicted in the inflationary scenario. Several experiments
have been designed or planned to observe B-modes. In this work we focus on the
forthcoming Large Scale Polarization Explorer (LSPE) experiment, that will be
devoted to the accurate measurement of CMB polarization at large angular
scales. LSPE consists of a balloon-borne bolometric instrument, the Short
Wavelength Instrument for the Polarization Explorer (SWIPE), and a ground-based
coherent polarimeter array, the STRatospheric Italian Polarimeter (STRIP).
SWIPE will employ a rotating Half Wave Plate (HWP) polarization modulator to
mitigate the systematic effects due to instrumental non-idealities. We present
here preliminary forecasts aimed at optimizing the HWP configuration.Comment: 6 pages, 4 figures, proceedings of the 7th Young Researcher Meeting,
Torino, Oct 24th-26th 201
Optimal strategy for polarization modulation in the LSPE-SWIPE experiment
CMB B-mode experiments are required to control systematic effects with an
unprecedented level of accuracy. Polarization modulation by a half wave plate
(HWP) is a powerful technique able to mitigate a large number of the
instrumental systematics. Our goal is to optimize the polarization modulation
strategy of the upcoming LSPE-SWIPE balloon-borne experiment, devoted to the
accurate measurement of CMB polarization at large angular scales. We depart
from the nominal LSPE-SWIPE modulation strategy (HWP stepped every 60 s with a
telescope scanning at around 12 deg/s) and perform a thorough investigation of
a wide range of possible HWP schemes (either in stepped or continuously
spinning mode and at different azimuth telescope scan-speeds) in the frequency,
map and angular power spectrum domain. In addition, we probe the effect of
high-pass and band-pass filters of the data stream and explore the HWP response
in the minimal case of one detector for one operation day (critical for the
single-detector calibration process). We finally test the modulation
performance against typical HWP-induced systematics. Our analysis shows that
some stepped HWP schemes, either slowly rotating or combined with slow
telescope modulations, represent poor choices. Moreover, our results point out
that the nominal configuration may not be the most convenient choice. While a
large class of spinning designs provides comparable results in terms of pixel
angle coverage, map-making residuals and BB power spectrum standard deviations
with respect to the nominal strategy, we find that some specific configurations
(e.g., a rapidly spinning HWP with a slow gondola modulation) allow a more
efficient polarization recovery in more general real-case situations. Although
our simulations are specific to the LSPE-SWIPE mission, the general outcomes of
our analysis can be easily generalized to other CMB polarization experiments.Comment: 11 pages, 9 figures, accepted for publication in A&
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