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- Aghanim, N., et al.
(author)
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Planck 2018 results XII. Galactic astrophysics using polarized dust emission
- 2020
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 641
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Journal article (peer-reviewed)abstract
- Observations of the submillimetre emission from Galactic dust, in both total intensity I and polarization, have received tremendous interest thanks to the Planck full-sky maps. In this paper we make use of such full-sky maps of dust polarized emission produced from the third public release of Planck data. As the basis for expanding on astrophysical studies of the polarized thermal emission from Galactic dust, we present full-sky maps of the dust polarization fraction p, polarization angle psi, and dispersion function of polarization angles ?. The joint distribution (one-point statistics) of p and N-H confirms that the mean and maximum polarization fractions decrease with increasing N-H. The uncertainty on the maximum observed polarization fraction, (max) = 22.0(-1.4)(+3.5) p max = 22 . 0 - 1.4 + 3.5 % at 353 GHz and 80 ' resolution, is dominated by the uncertainty on the Galactic emission zero level in total intensity, in particular towards diffuse lines of sight at high Galactic latitudes. Furthermore, the inverse behaviour between p and ? found earlier is seen to be present at high latitudes. This follows the ?proportional to p(-1) relationship expected from models of the polarized sky (including numerical simulations of magnetohydrodynamical turbulence) that include effects from only the topology of the turbulent magnetic field, but otherwise have uniform alignment and dust properties. Thus, the statistical properties of p, psi, and ? for the most part reflect the structure of the Galactic magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map ?xp, looking for residual trends. While the polarization fraction p decreases by a factor of 3-4 between N-H=10(20) cm(-2) and N-H=2x10(22) cm(-2), out of the Galactic plane, this product ?xp only decreases by about 25%. Because ? is independent of the grain alignment efficiency, this demonstrates that the systematic decrease in p with N-H is determined mostly by the magnetic-field structure and not by a drop in grain alignment. This systematic trend is observed both in the diffuse interstellar medium (ISM) and in molecular clouds of the Gould Belt. Second, we look for a dependence of polarization properties on the dust temperature, as we would expect from the radiative alignment torque (RAT) theory. We find no systematic trend of ?xp with the dust temperature T-d, whether in the diffuse ISM or in the molecular clouds of the Gould Belt. In the diffuse ISM, lines of sight with high polarization fraction p and low polarization angle dispersion ? tend, on the contrary, to have colder dust than lines of sight with low p and high ?. We also compare the Planck thermal dust polarization with starlight polarization data in the visible at high Galactic latitudes. The agreement in polarization angles is remarkable, and is consistent with what we expect from the noise and the observed dispersion of polarization angles in the visible on the scale of the Planck beam. The two polarization emission-to-extinction ratios, R-P/p and R-S/V, which primarily characterize dust optical properties, have only a weak dependence on the column density, and converge towards the values previously determined for translucent lines of sight. We also determine an upper limit for the polarization fraction in extinction, p(V)/E(B-V), of 13% at high Galactic latitude, compatible with the polarization fraction p approximate to 20% observed at 353 GHz. Taken together, these results provide strong constraints for models of Galactic dust in diffuse gas.
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- Akrami, Y., et al.
(author)
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Planck 2018 results : XI. Polarized dust foregrounds
- 2020
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In: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 641
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Journal article (peer-reviewed)abstract
- The study of polarized dust emission has become entwined with the analysis of the cosmic microwave background (CMB) polarization in the quest for the curl-like B-mode polarization from primordial gravitational waves and the low-multipole E-mode polarization associated with the reionization of the Universe. We used the new Planck PR3 maps to characterize Galactic dust emission at high latitudes as a foreground to the CMB polarization and use end-to-end simulations to compute uncertainties and assess the statistical significance of our measurements. We present PlanckEE, BB, and TE power spectra of dust polarization at 353 GHz for a set of six nested high-Galactic-latitude sky regions covering from 24 to 71% of the sky. We present power-law fits to the angular power spectra, yielding evidence for statistically significant variations of the exponents over sky regions and a difference between the values for the EE and BB spectra, which for the largest sky region are alpha (EE)=-2.42 +/- 0.02 and alpha (BB)=-2.54 +/- 0.02, respectively. The spectra show that the TE correlation and E/B power asymmetry discovered by Planck extend to low multipoles that were not included in earlier Planck polarization papers due to residual data systematics. We also report evidence for a positive TB dust signal. Combining data from Planck and WMAP, we have determined the amplitudes and spectral energy distributions (SEDs) of polarized foregrounds, including the correlation between dust and synchrotron polarized emission, for the six sky regions as a function of multipole. This quantifies the challenge of the component-separation procedure that is required for measuring the low-l reionization CMB E-mode signal and detecting the reionization and recombination peaks of primordial CMB B modes. The SED of polarized dust emission is fit well by a single-temperature modified black-body emission law from 353 GHz to below 70 GHz. For a dust temperature of 19.6 K, the mean dust spectral index for dust polarization is beta (P)(d) = 1.53 +/- 0.02 beta d P = 1.53 +/- 0.02 . The difference between indices for polarization and total intensity is beta (P)(d)-beta (I)(d) = 0.05 +/- 0.03 beta d P - beta d I =0.05 +/- 0.03 . By fitting multi-frequency cross-spectra between Planck data at 100, 143, 217, and 353 GHz, we examine the correlation of the dust polarization maps across frequency. We find no evidence for a loss of correlation and provide lower limits to the correlation ratio that are tighter than values we derive from the correlation of the 217- and 353 GHz maps alone. If the Planck limit on decorrelation for the largest sky region applies to the smaller sky regions observed by sub-orbital experiments, then frequency decorrelation of dust polarization might not be a problem for CMB experiments aiming at a primordial B-mode detection limit on the tensor-to-scalar ratio r similar or equal to 0.01 at the recombination peak. However, the Planck sensitivity precludes identifying how difficult the component-separation problem will be for more ambitious experiments targeting lower limits on r.
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- Kehoe, Laura, et al.
(author)
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Make EU trade with Brazil sustainable
- 2019
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Journal article (other academic/artistic)
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- Silva, M., et al.
(author)
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EMB3Rs: A game-changer tool to support waste heat recovery and reuse
- 2024
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In: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 309
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Journal article (peer-reviewed)abstract
- At a time when European countries try to cope with escalating energy prices while decarbonizing their economies, waste heat recovery and reuse arises as part of the solution for sustainable energy transitions. The lack of appropriate assessment tools has been pointed out as one of the main barriers to the wider deployment of waste heat recovery projects and as a reason why its potential remains largely untapped. The EMB3Rs platform emerges as an online, open-source, comprehensive and novel tool that provides an integrated assessment of different types of waste heat recovery solutions, (e.g. internal or external) and comprises several analysis dimensions (e.g. physical, geographical, technical, market, and business models). It has been developed together with stakeholders, and tested in a number of representative contexts, covering both industrial and heat network applications. This has demonstrated the enormous potential of the tool in dealing with complex simulations, while delivering accurate results within a significantly lower time-frame than traditional analysis. The EMB3Rs tool removes important barriers such as analysis costs, time and complexity for the user, and aims at supporting a wider investment in waste heat recovery and reuse by providing an integrated estimation of the costs and benefits of such projects. This paper describes the tool and illustrates how it can be applied to help unlock the potential of waste heat recovery across European countries.
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- Araujo, Igor M., et al.
(author)
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Accelerating VNF-based Deep Packet Inspection with the use of GPUs
- 2018
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In: 2018 20TH ANNIVERSARY INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538666050
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Conference paper (peer-reviewed)abstract
- Network Function Virtualization (NFV) replaces the hardware that supports packet processing in network operation from specific-by general-purpose ones, reducing costs and bringing more flexibility and agility to the network operation. However, this shift can cause performance losses due to the non-optimal packet processing capabilities of the general-purpose hardware. Moreover, supporting the line rate of optical network channels with Virtualized Network Functions (VNFs) is a challenging task. This work analyzes the benefits of using Graphics Processing Units (GPUs) to support the execution of a Deep Packet Inspection (DPI) VNF towards supporting the line rate of an optical channel. The use of GPUs in VNFs has a great potential to increase throughput, but the delay incurred might be an issue for some functions. Our simulation was performed using an Intrusion Detection Systems (IDS) which performs DPI deployed as a VNF under real-world traffic scaled to high bit rates. Results show that the packet processing speedup achieved by using GPUs can reach up to 19 times, at the expense of a higher packet delay.
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- Araujo, Igor M., et al.
(author)
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Availability-Guaranteed Service Function Chain Provisioning with Optional Shared Backups
- 2020
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In: 2020 16TH INTERNATIONAL CONFERENCE ON THE DESIGN OF RELIABLE COMMUNICATION NETWORKS DRCN 2020. - : IEEE.
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Conference paper (peer-reviewed)abstract
- The dynamic provisioning of Service Function Chain (SFC) using Virtual Network Functions (VNFs) is a challenging problem, especially for availability-constrained services. The provisioning of backup resources is often used to ensure that availability requirements are fulfilled. However, the assignment of backup resources should be carefully designed to avoid resource inefficiencies as much as possible. This paper proposes the Optional Backup with Shared Path and Shared Function (OBSPSF) strategy, which aims at improving resource efficiency while fulfilling the availability requirements of SFC requests. The strategy uses optional backup provisioning to ensure that backup resources are assigned only when strictly needed (i.e., when the SFC alone does not meet the availability constraint). Moreover, OBSPSF encourages backup sharing (among both connectivity and backup VNFs) to reduce the backup resource overhead. Results show that the strategy can accommodate orders-of-magnitude more services than benchmark heuristics from the literature.
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- Spiro, Neta, et al.
(author)
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Perspectives on Musical Care Throughout the Life Course: Introducing the Musical Care International Network
- 2023
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In: Music & Science. - : SAGE Publications. - 2059-2043. ; 6
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Journal article (peer-reviewed)abstract
- In this paper we report on the inaugural meetings of the Musical Care International Network held online in 2022. The term “musical care” is defined by Spiro and Sanfilippo (2022) as “the role of music—music listening as well as music-making—in supporting any aspect of people's developmental or health needs” (pp. 2–3). Musical care takes varied forms in different cultural contexts and involves people from different disciplines and areas of expertise. Therefore, the Musical Care International Network takes an interdisciplinary and international approach and aims to better reflect the disciplinary, geographic, and cultural diversity relevant to musical care. Forty-two delegates participated in 5 inaugural meetings over 2 days, representing 24 countries and numerous disciplines and areas of practice. Based on the meetings, the aims of this paper are to (1) better understand the diverse practices, applications, contexts, and impacts of musical care around the globe and (2) introduce the Musical Care International Network. Transcriptions of the recordings, alongside notes taken by the hosts, were used to summarise the conversations. The discussions developed ideas in three areas: (a) musical care as context-dependent and social, (b) musical care's position within the broader research and practice context, and (c) debates about the impact of and evidence for musical care. We can conclude that musical care refers to context-dependent and social phenomena. The term musical care was seen as useful in talking across boundaries while not minimizing individual disciplinary and professional expertise. The use of the term was seen to help balance the importance and place of multiple disciplines, with a role to play in the development of a collective identity. This collective identity was seen as important in advocacy and in helping to shape policy. The paper closes with proposed future directions for the network and its emerging mission statement.
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