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 work’s major British and American English translations published over a period of around 130 years. Pinocchio is a transnational classic of children’s literature that ideally addresses a dual audience (O’Sullivan 1993, Lathey 2006). Food and hunger are often ‘evoked’ 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 children’s 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 readers’ 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

THE MULTIMODAL REPRESENTATION OF “IDEAS WORTH SPREADING” 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 speaker’s 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 tedsters’ 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 “Ideas worth spreading” 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 speaker’s 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 tedsters’ 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&