Oceanic lithosphere-asthenosphere boundaryfrom surface wave dispersion data

International audienceAbstract According to different types of observations, the nature of lithosphere-asthenosphereboundary (LAB) is controversial. Using a massive data set of surface wave dispersions in a broad periodrange (15–300 s), we have developed a three-dimensional upper mantle tomographic model (first-orderperturbation theory) at the global scale. This is used to derive maps of the LAB from the resolved elasticparameters. The key effects of shallow layers and anisotropy are taken into account in the inversion process.We investigate LAB distribution primarily below the oceans, according to different kinds of proxies thatcorrespond to the base of the lithosphere from the shear velocity variation at depth, the amplituderadial anisotropy, and the changes in azimuthal anisotropy G orientation. The estimations of the LAB depthbased on the shear velocity increase from a thin lithosphere (∼20 km) in the ridges, to a thick old-oceanlithosphere (∼120–130 km). The radial anisotropy proxy shows a very fast increase in the LAB depth fromthe ridges, from ∼50 km to the older ocean where it reaches a remarkable monotonic subhorizontal profile(∼70–80 km). The LAB depths inferred from the azimuthal anisotropy proxy show deeper values for theincreasing oceanic lithosphere (∼130–135 km). The difference between the evolution of the LAB depth withthe age of the oceanic lithosphere computed from the shear velocity and azimuthal anisotropy proxies andfrom the radial anisotropy proxy raises questions about the nature of the LAB in the oceanic regions and ofthe formation of the oceanic plate

Indicadores de acciones técnicas y de intensidad de acuerdo con las posiciones de los jugadores en partidas oficiales de la liga brasileña de baloncesto

El objetivo de este estudio fue analizar los indicadores de las acciones técnicas (IAT) y de intensidad de acuerdo con las posiciones de los jugadores, en seis partidos oficiales de la Liga de Baloncesto de Brasil. Participaron de este estudio 10 jugadores de la elite del baloncesto (27,60±5,54 años). La frecuencia de los IAT del partido (ΣIP) y el índice de eficiencia (IE), fueron extraídos de las estadísticas oficiales. Los atletas jugaron con transmisores de FC para determinación de la intensidad. Fueron producidas medidas descriptivas; y calculada la magnitud de la diferencia [Δ%=(1-(IE÷ΣIP))*100]. Cuando los jugadores fueron clasificados pela Δ%, se clasificaron automáticamente por las respectivas posiciones, en 80% de los casos. Los jugadores de las posiciones 4 y 5 juegan cerca del cesto y realizan el juego más seguro y eficiente; jugadores de la posición 1 juegan de frente para el cesto, organizan el juego colectivo, lo que también puede contribuir con acciones más seguras. Los jugadores de la posición 5 tuvieron el mayor Δ% entre IE e ΣIP, representando juego seguro y eficiente; jugadores con más edad actuaron en menor intensidad; y el juego de baloncesto se desarrolló (promedia) poco arriba de la FC del umbral de lactato.The aim of this study was to analyze indicators of technical actions (ITA) and intensity according to the players positions in six official matches of the Brazilian Basketball League. Ten elite basketball male players participated in this study (27.60±5.54years). The total frequency of matches’ indicators (ΣMI - sum of all matches indicators of each athlete included in the stats) and the efficiency ratio (ER) from matches’ official stats were the ITA considered. To check the intensity, athletes played with HR transmitter. Were produced descriptive measures; and the magnitude of difference (Δ%) between ΣMI and ER second player [Δ%=(1-(ER÷ΣMI))*100] was calculated. It was observed that when players were classified by Δ% they were automatically classified by their respective positions in 80% of cases. Players’ positions 4 and 5 work closer to the basket and perform the safest and most efficient team play; players’ position 1 plays facing to the basket, organizes the collective game, has the largest ball possession volume which can also enable a safer game. Players' position 5 had higher Δ% between ΣMI and ER, representing safer and efficient game; older players had lower intensity; and the basketball game was developed on average slightly above the lactate threshold HR.O objetivo deste estudo foi analisar os indicadores das ações técnicas (IAT) e da intensidade de acordo com as posições dos jogadores, em seis partidas oficiais da Liga Brasileira de Basquetebol. Participaram deste estudo 10 jogadores da elite do basquetebol (27,60±5,54 anos). A frequência total dos IAT da partida (ΣIJ – soma dos indicadores de jogo de cada atleta) e o índice de eficiência (IE), foram extraídos das estatísticas oficiais das partidas. Os atletas jogaram com transmissores de frequência cardíaca (FC) para determinação da intensidade. Foram produzidas medidas descritivas; e calculada a magnitude da diferença [Δ%=(1-(ΣIE÷IJ))*100]. Quando os jogadores foram classificados pela Δ%, classificaram-se automaticamente pelas respectivas posições, em 80% dos casos. Os principais resultados apontam: i) jogadores das posições 4 e 5, que jogam próximos à cesta realizam o jogo mais seguro e eficiente; ii) jogadores da posição 1, que jogam de frente para a cesta, organizam o jogo coletivo e apresentam maior posse de bola; iii) os jogadores da posição 5 tiveram o maior Δ% entre IE e ΣIJ; iv) jogadores com idade mais elevada atuaram em menor intensidade; e por fim, v) o jogo de basquetebol se desenvolve com FCmédia pouco acima da FC de limiar de lactato.peerReviewe

Measuring CP violation and mass ordering in joint long baseline experiments with superbeams

We propose to measure the CP phase $\delta_{\rm CP}$, the magnitude of the neutrino mixing matrix element $|U_{e3}|$ and the sign of the atmopheric scale mass--squared difference $\Delta{\rm m}^2_{31}$ with a superbeam by the joint analysis of two different long baseline neutrino oscillation experiments. One is a long baseline experiment (LBL) at 300 km and the other is a very long baseline (VLBL) experiment at 2100 km. We take the neutrino source to be the approved high intensity proton synchrotron, HIPA. The neutrino beam for the LBL is the 2-degree off-axis superbeam and for the VLBL, a narrow band superbeam. Taking into account all possible errors, we evaluate the event rates required and the sensitivities that can be attained for the determination of $\delta_{\rm CP}$ and the sign of $\Delta m^2_{31}$. We arrive at a representative scenario for a reasonably precise probe of this part of the neutrino physics.Comment: 25 RevTEX pages, 16 PS figures, revised figure captions and references adde

Modeling realistic Earth matter density for CP violation in neutrino oscillation

We examine the effect of a more realistic Earth matter density model which takes into account of the local density variations along the baseline of a possi ble 2100 km very long baseline neutrino oscillation experiment. Its influence to the measurement of CP violation is investigated and a comparison with the commonly used global density models made. Significant differences are found in the comparison of the results of the different density models.Comment: 16 pages, 8 figure

CP violating neutrino oscillation and uncertainties in Earth matter density

We propose a statistical formulation to estimate possible errors in long baseline neutrino oscillation experiments caused by uncertainties in the Earth matter density. A quantitative investigation of the effect is made on the CP asymmetry in future neutrino factory experiments.Comment: Latex, 10 pages, 5 figure

Indicators of technical actions and intensity according to players’ positions in official matches of the brazilian basketball league

Abstract The aim of this study was to analyze indicators of technical actions (ITA) and intensity according to the players positions in six official matches of the Brazilian Basketball League. Ten elite basketball male players participated in this study (27.60±5.54years). The total frequency of matches’ indicators (∑MI - sum of all matches indicators of each athlete included in the stats) and the efficiency ratio (ER) from matches’ official stats were the ITA considered. To check the intensity, athletes played with HR transmitter. Were produced descriptive measures; and the magnitude of difference (Δ%) between ∑MI and ER second player [Δ%=(1-(ER÷∑MI))*100] was calculated. It was observed that when players were classified by Δ% they were automatically classified by their respective positions in 80% of cases. Players’ positions 4 and 5 work closer to the basket and perform the safest and most efficient team play; players’ position 1 plays facing to the basket, organizes the collective game, has the largest ball possession volume which can also enable a safer game. Players' position 5 had higher Δ% between ∑MI and ER, representing safer and efficient game; older players had lower intensity; and the basketball game was developed on average slightly above the lactate threshold HR

Earth's free oscillations recorded by free-fall OBS ocean-bottom seismometers at the Lesser Antilles subduction zone

International audienceThree unburied ocean bottom seismometers (OBS) equipped with Trillium 240 s broad-band seismometers recorded spheroidal free oscillations of the Earth out to periods over 1000 s period, for the M = 8.1, April 1, 2007 Solomon Islands earthquake. In contrast to broadband observatories of the global network that operate in quiet continental locations, these instruments were dropped on the several-km thick layer of sediments of the forearc and accretionary wedge of the Lesser Antilles subduction zone. Furthermore, a high ambient noise level due to the ocean surface infragravity waves is expected to cover the frequency band of Earth's normal modes band when recorded at these sites. In spite of these hostile environmental conditions, the frequency of clearly defined peaks of the Earth's normal modes were measured after the earthquake. This suggests that the recording of normal modes and long period waves can be extended to parts of the hitherto inaccessible ocean with currently available OBS technology

Anisotropic structure of the African upper mantle from Rayleigh and Love wave tomography

International audienceThe geodynamics of the mantle below Africa is not well understood and anisotropy tomography can provide new insight into the coupling between the African plate and the underlying mantle convection. In order to study the anisotropic structure of the upper mantle beneath Africa, we have measured phase velocities of 2900 Rayleigh and 1050 Love waves using the roller-coaster algorithm [Beucler, E., Stutzmann, E., Montagner, J.-P., 2003. Surface-wave higher mode phase velocity measurments, using a roller-coaster type algorithm. Geophys. J. Int. 155 (1), 289–307]. These phase velocities have been inverted to obtain a new tomographic model that gives access to isotropic SV-wave velocity perturbations, azimuthal and radial anisotropies. Isotropic SV-wave velocity maps have a lateral resolution of 500 km. Anisotropy parameters have a lateral resolution of 1000 km which is uniform over Africa for azimuthal anisotropy but decreases at the West and South of Africa for radial anisotropy. At shallow depth, azimuthal anisotropy varies over horizontal distances much smaller than the continent scale. At 280 km depth, azimuthal anisotropy is roughly N-S, except in the Afar area, which might indicate differential motion between the African plate and the underlying mantle. The three cratons of West Africa, Congo and Kalahari are associated with fast velocities and transverse anisotropy that decrease very gradually down to 300 km depth. On the other hand, we observe a significant change in the direction and amplitude of azimuthal anisotropy at about 180 km depth, which could be the signature of the root of these cratons. The Tanzania craton is a shallower structure than the other African cratons and the slow velocities (−2%) observed on the maps at 180 and 280 km depth could be the signature of hot material such as a plume head below the craton. This slow velocity anomaly extends toward the Afar and azimuthal anisotropy fast directions are N-S at 180 km depth, indicating a possible interaction between the Tanzania small plume and the Afar. The Afar plume is associated with a very slow velocity anomaly (−6%) which extens below the Red sea, the Gulf of Aden and the Ethiopian rift at 80 km depth. The Afar plume can be observed down to our deepest depth (300 km) and is associated with radial anisotropy smaller than elsewhere in Africa, suggesting active upwelling. Azimuthal anisotropy directions change with increasing depth, being N-S below the Red sea and Gulf of Aden at 80 km depth and E–W to NE–SW at 180 km depth. The Afar plume is not connected with the smaller hotspots of Central Africa, which are associated either with shallow slow velocities for Mt Cameroon or with no particular velocity anomaly and N-S azimuthal anisotropy for the hotspots of Tibesti, Darfur and Hoggar. A shallow origin for these hotspots is in agreement with their normal 3He/4He ratio and with their location in a region that had been weakened by the rifting of West and Central Africa