| 1. |
- Actis, M., et al.
(författare)
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Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
- 2011
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
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Tidskriftsartikel (refereegranskat)abstract
- Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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| 2. |
- Ambrazaitis, Gilbert, et al.
(författare)
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Acoustic features of multimodal prominences : Do visual beat gestures affect verbal pitch accent realization?
- 2017
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Ingår i: Proceedings of The 14th International Conference on Auditory-Visual Speech Processing (AVSP2017). - Stockholm : International Speech Communication Association. - 2308-975X.
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Konferensbidrag (refereegranskat)abstract
- The interplay of verbal and visual prominence cues has attracted recent attention, but previous findings are inconclusive as to whether and how the two modalities are integrated in the production and perception of prominence. In particular, we do not know whether the phonetic realization of pitch accents is influenced by co-speech beat gestures, and previous findings seem to generate different predictions. In this study, we investigate acoustic properties ofprominent words as a function of visual beat gestures in a corpus of read news from Swedish television. The corpus was annotated for head and eyebrow beats as well as sentence-level pitch accents. Four types of prominence cues occurredparticularly frequently in the corpus: (1) pitch accent only, (2) pitch accent plus head, (3) pitch accent plus head plus eyebrows, and (4) head only. The results show that (4) differs from (1-3) in terms of a smaller pitch excursion and shorter syllable duration. They also reveal significantly larger pitch excursions in (2) than in (1), suggesting that the realization of a pitch accent is to some extent influenced by the presence of visual prominence cues. Results are discussed in terms of the interaction between beat gestures and prosody with a potential functional difference between head and eyebrow beats.
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| 3. |
- Ambrazaitis, Gilbert, 1979-, et al.
(författare)
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Auditory vs. audiovisual prominence ratings of speech involving spontaneously produced head movements
- 2022
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Ingår i: Proceedings of the 11th International Conference on Speech Prosody : Speech Prosody 2022 - Speech Prosody 2022. - : International Speech Communication Association. - 2333-2042. ; , s. 352-356, s. 352-356
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Konferensbidrag (refereegranskat)abstract
- Visual information can be integrated in prominence perception, but most available evidence stems from controlled experimental settings, often involving synthetic stimuli. The present study provides evidence from spontaneously produced head gestures that occurred in Swedish television news readings. Sixteen short clips (containing 218 words in total) were rated for word prominence by 85 adult volunteers in a between-subjects design (44 in an audio-visual vs. 41 in an audio-only condition) using a web-based rating task. As an initial test of overall rating behavior, average prominence across all 218 words was compared between the two conditions, revealing no significant difference. In a second step, we compared normalized prominence ratings between the two conditions for all 218 words individually. These results displayed significant (or near significant, p
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| 4. |
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| 5. |
- Ambrazaitis, Gilbert, 1979-, et al.
(författare)
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Multimodal prominences : Exploring the patterning and usage of focal pitch accents, head beats and eyebrow beats in Swedish television news readings
- 2017
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Ingår i: Speech Communication. - : Elsevier B.V.. - 0167-6393 .- 1872-7182. ; 95, s. 100-113
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Tidskriftsartikel (refereegranskat)abstract
- Facial beat gestures align with pitch accents in speech, functioning as visual prominence markers. However, it is not yet well understood whether and how gestures and pitch accents might be combined to create different types of multimodal prominence, and how specifically visual prominence cues are used in spoken communication. In this study, we explore the use and possible interaction of eyebrow (EB) and head (HB) beats with so-called focal pitch accents (FA) in a corpus of 31 brief news readings from Swedish television (four news anchors, 986 words in total), focusing on effects of position in text, information structure as well as speaker expressivity. Results reveal an inventory of four primary (combinations of) prominence markers in the corpus: FA+HB+EB, FA+HB, FA only (i.e., no gesture), and HB only, implying that eyebrow beats tend to occur only in combination with the other two markers. In addition, head beats occur significantly more frequently in the second than in the first part of a news reading. A functional analysis of the data suggests that the distribution of head beats might to some degree be governed by information structure, as the text-initial clause often defines a common ground or presents the theme of the news story. In the rheme part of the news story, FA, HB, and FA+HB are all common prominence markers. The choice between them is subject to variation which we suggest might represent a degree of freedom for the speaker to use the markers expressively. A second main observation concerns eyebrow beats, which seem to be used mainly as a kind of intensification marker for highlighting not only contrast, but also value, magnitude, or emotionally loaded words; it is applicable in any position in a text. We thus observe largely different patterns of occurrence and usage of head beats on the one hand and eyebrow beats on the other, suggesting that the two represent two separate modalities of visual prominence cuing.
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| 6. |
- Ambrazaitis, Gilbert, 1979-, et al.
(författare)
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Word prominence ratings in Swedish television news readings : Effects of pitch accents and head movements
- 2020
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Ingår i: Proceedings of the International Conference on Speech Prosody. - : International Speech Communication Association. - 2333-2042. ; , s. 314-318, s. 314-318
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Konferensbidrag (refereegranskat)abstract
- Prosodic prominence is a multimodal phenomenon where pitch accents are frequently aligned with visible movements by the hands, head, or eyebrows. However, little is known about how such movements function as visible prominence cues in multimodal speech perception with most previous studies being restricted to experimental settings. In this study, we are piloting the acquisition of multimodal prominence ratings for a corpus of natural speech (Swedish television news readings). Sixteen short video clips (218 words) of news readings were extracted from a larger corpus and rated by 44 native Swedish adult volunteers using a web-based set-up. The task was to rate each word in a clip as either non-prominent, moderately prominent or strongly prominent based on audiovisual cues. The corpus was previously annotated for pitch accents and head movements. We found that words realized with a pitch accent and head movement tended to receive higher prominence ratings than words with a pitch accent only. However, we also examined ratings for a number of carefully selected individual words, and these case studies suggest that ratings are affected by complex relations between the presence of a head movement and its type of alignment, the word's F0 profile, and semantic and pragmatic factors.
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| 7. |
- Anderbrant, Olle, et al.
(författare)
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Pheromone of the elm bark beetle Scolytus laevis (Coleoptera Scolytidae) : stereoisomers of 4-methyl-3-heptanol reduce interspecific competition
- 2010
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Ingår i: Chemoecology. - : Springer Science and Business Media LLC. - 0937-7409 .- 1423-0445. ; 20:3, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers, but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC-MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer (3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees.
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| 8. |
- Bring, Torun, et al.
(författare)
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Colour development in copper ruby alkali silicate glasses : Part 1. The impact of tin (II) oxide, time and temperature
- 2007
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Ingår i: Glass Technology, Eur J Glass Sci Technol A. - : Society of Glass Technology. ; 48:2, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- The development of the red colour in copper ruby alkali silicate glasses has been studied by means of ultraviolet/visible spectroscopy, TEM and EXAFS. The results show that in both red and slightly overstruck, brownish glasses the colour is due to clusters of metallic copper. Before striking non-coloured glasses contain mainly cuprous ions, Cu+. Tin acts as a reducing agent but also has an accelerating effect on colour development.
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| 9. |
- Bring, Torun, et al.
(författare)
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Selenium : molybdenum-based coloration of alkali silicate glasses
- 2007
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Ingår i: Glass Technology. - : Society of Glass Technology. - 0017-1050. ; 48:5, s. 213-221
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between selenium and molybdenum in reduced alkali silicate melts, resulting in red glasses has been studied. The oxidation state of Mo is Mo(VI) as evidenced by XANES and ESCA results. Selenium is present in a reduced state, as indicated by ultraviolet/visible spectroscopy and XANES. The colour is described by ultraviolet/visible spectra and CIE colour coordinates. The main absorption peaks are at 450 and 540 nm. Similar bands are reported for MoOSe32−. Several commonly used glass components must be avoided in the batch, as they prevent formation of the red colour.
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| 10. |
- Dalarsson, Mariana, et al.
(författare)
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Absorption and optimal plasmonic resonances for small ellipsoidal particles in lossy media
- 2017
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Ingår i: Journal of Physics D. - : Institute of Physics (IOP). - 0022-3727 .- 1361-6463. ; 50:34
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Tidskriftsartikel (refereegranskat)abstract
- A new simplified formula is derived for the absorption cross section of small dielectric ellipsoidal particles embedded in lossy media. The new expression leads directly to a closed form solution for the optimal conjugate match with respect to the surrounding medium, i.e. the optimal permittivity of the ellipsoidal particle that maximizes the absorption at any given frequency. This defines the optimal plasmonic resonance for the ellipsoid. The optimal conjugate match represents a metamaterial in the sense that the corresponding optimal permittivity function may have negative real part (inductive properties), and can not in general be implemented as a passive material over a given bandwidth. A necessary and sufficient condition is derived for the feasibility of tuning the Drude model to the optimal conjugate match at a single frequency, and it is found that all the prolate spheroids and some of the (not too flat) oblate spheroids can be tuned into optimal plasmonic resonance at any desired center frequency. Numerical examples are given to illustrate the analysis. Except for the general understanding of plasmonic resonances in lossy media, it is also anticipated that the new results can be useful for feasibility studies with e.g. the radiotherapeutic hyperthermia based methods to treat cancer based on electrophoretic heating in gold nanoparticle suspensions using microwave radiation.
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