| 1. |
- Schael, S, et al.
(author)
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Precision electroweak measurements on the Z resonance
- 2006
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Research review (peer-reviewed)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Merle, Renaud E., 1976-, et al.
(author)
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Cretaceous seamounts along the continent–ocean transition of the Iberian margin : U–Pb ages and Pb–Sr–Hf isotopes
- 2006
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In: Geochimica et Cosmochimica Acta. - 0016-7037 .- 1872-9533. ; 70:19, s. 4950-4976
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Journal article (peer-reviewed)abstract
- To elucidate the age and origin of seamounts in the eastern North Atlantic, 54 titanite and 10 zircon fractions were dated by the U–Pb chronometer, and initial Pb, Sr, and Hf isotope ratios were measured in feldspars and zircon, respectively. Rocks analyzed are essentially trachy-andesites and trachytes dredged during the “Tore Madeira” cruise of the Atalante in 2001. The ages reveal different pulses of alkaline magmatism occurring at 104.4±1.4 (2σ) Ma and 102.8±0.7 Ma on the Sponge Bob seamount, at 96.3±1.0 Ma on Ashton seamount, at 92.3±3.8 Ma on the Gago Coutinho seamount, at 89.3±2.3 Ma and 86.5±3.4 Ma on the Jo Sister volcanic complex, and at 88.3±3.3 Ma, 88.2±3.9, and 80.5±0.9 Ma on the Tore locality. No space–time correlation is observed for alkaline volcanism in the northern section of the Tore-Madeira Rise, which occurred 20–30 m.y. after opening of the eastern North Atlantic. Initial isotope signatures are: 19.139–19.620 for 206Pb/204Pb, 15.544–15.828 for 207Pb/204Pb, 38.750–39.936 for 208Pb/204Pb, 0.70231–0.70340 for 87Sr/86Sr, and +6.9 to +12.9 for initial epsilon Hf. These signatures are different from Atlantic MORB, the Madeira Archipelago and the Azores, but they lie in the field of worldwide OIB. The Cretaceous seamounts therefore seem to be generated by melts from a OIB-type source that interact with continental lithospheric mantle lying formerly beneath Iberia and presently within the ocean–continent transition zone. Inheritance in zircon and high 207Pb of initial Pb substantiate the presence of very minor amounts of continental material in the lithospheric mantle. A long-lived thermal anomaly is the most plausible explanation for alkaline magmatism since 104 Ma and it could well be that the same anomaly is still the driving force for tertiary and quaternary alkaline magmatism in the eastern North Atlantic region. This hypothesis is agreement with the plate-tectonic position of the region since Cretaceous time, including an about 30° anti-clockwise rotation of Iberia.
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| 3. |
- Merle, Renaud E., 1976-, et al.
(author)
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Segregation vesicles, cylinders, and sheets in vapor-differentiated pillow lavas : examples from Tore-Madeira Rise and Chile Triple Junction
- 2005
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In: Journal of Volcanology and Geothermal Research. - 0377-0273 .- 1872-6097. ; 141:1, s. 109-122
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Journal article (peer-reviewed)abstract
- We conducted a detailed field and laboratory study of internal segregation structures of two hand-size pillow lavas samples. They were dredged, respectively, on the Josephine seamount, Tore-Madeira Rise (TMR), and on a small quaternary volcanic edifice located on the continental edge of the trench close to the Chile Triple Junction (CTJ). Both pillows display a combination of four types of segregation structures (spherical vesicles, pipe vesicles, vesicle cylinders, and vesicle sheets) observed so far only within subaerial basalt flows typically 2–10 m thick. In particular, the samples offer a remarkable exposure of the transition between pipe vesicles and cylinders. We show that the vesicle sheets are not generated by the same mechanism in both occurrences; they do not seem to be connected to cylinders in the CTJ pillow as they are in the TMR pillow. The two pillows are geochemically distinct, the TMR being alkaline and the CTJ calc–alkaline. Two types of internal differentiation are proposed. The first one implies the extraction of the residual liquid from the host lava and transport towards the segregation structures, whereas the other one results from in situ crystallization within one given structure. In the latter case, glass composition is highly dependant on the nature of the neighbouring crystallizing minerals. The degree of crystallization required to produce a crystal framework strong enough for generating the segregation structures seems to be lower in pillows (ca. 25% crystallization) than in vapor-differentiated basaltic lava flows (35% crystallization).
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| 4. |
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| 5. |
- Sjöström, Anders, et al.
(author)
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Using cepstral coefficients for Inhalation pause detection in spontaneous speech
- 2005
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In: Proceedings of SPECOM 2005. - 574520110X ; 1, s. 143-146
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Conference paper (peer-reviewed)abstract
- A method for recognizing inhalations in spontaneous speech is presented. It is similar to the template matching technique; a distance measure is calculated between a reference sound and an equally long portion of the same sound being tracked. A feature representation consisting of the standard Mel Frequency Cepstral Coefficients (MFCC), obtained by performing a discrete Cosine Transform of the mel-scaled filterbank spectrum is used. MFCC's are calculated every 5 ms. The comparison is then done by computing the euclidian distance between the cepstral coefficients of each frame of the two sounds. A low distance value means that the two compared inhalations are likely to be similar. The method can detect inhalations in both male and female spontaneous speech. The method is most suited for signals with low noise and high average intensity (studio recording) but can also be used on noisier recordings with lower average intensity, albeit with poorer results.
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