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262 results on '"Davy B"'

3. Diversity and resource selection of dung beetles in a relictual mountain forest in Brazil

Author

Davy B. Bérgamo, Carolina Nunes Liberal, Thais Aparecida Vitoriano Dantas, Fredy Alvarado, and Rosemberg Fernandes Menezes

Subjects
Habitat, Land use, Ecology, Insect Science, Species diversity, Dominance (ecology), Ecosystem, Biology, biology.organism_classification, Ecology, Evolution, Behavior and Systematics, Dung beetle, Trophic level, Global biodiversity
Abstract

Most of the tropical ecosystems are now altered, consequently modifying the species diversity, composition and feeding behaviours. Precisely, the survival of species is dependent on their characteristics to endure the novel environments immersed in human-dominated landscapes. Thus, comparative studies of how different community attributes and trophic guilds respond to changes in land use would be useful. In this study, we analyzed diversity, composition and food selection of dung beetles in an Atlantic forest enclave (Ombrophilous forest remnant) from North-eastern Brazil. We sampled dung beetles using 60 pitfall traps distributed in our study region. Diversity and composition were estimated by using Hill numbers (or the effective number of species) and biomass of individuals and were compared among three types of vegetation structure (forest, forest edge and open pastures) and four different types of baits (human, pig, chicken and cattle excrements). We found that diversity measures weighted by biomass allowed better detection of the variation between habitat types and food preference than weighted by the number of individuals. The dung beetle biomass indicates that the spatial dominance of open pastures promote a drastic impoverishment of dung beetle diversity and composition. We also found that β diversity shows an evidence of homogenization on the resource food selection, related with the preference in the attraction of dung beetles to exotic omnivores. Our results show that replacing forests with cattle pastures modifies diversity, species composition, and resource food selection patterns, which could affect the ecosystem provision by dung beetles. Despite our study region is immersed in a human-dominated-landscape, forest remnants continue to hold a high diversity assemblage compared with most degraded environments.

Published
2020

5. Upward‐Doming Zones of Gas Hydrate and Free Gas at the Bases of Gas Chimneys, New Zealand's Hikurangi Margin

Author

Crutchley, Gareth J., Mountjoy, J. J., Hillman, J. I. T., Turco, F., Watson, S., Flemings, P. B., Davy, B., Woelz, S., Gorman, A. R., Bialas, Jörg, Crutchley, Gareth J., Mountjoy, J. J., Hillman, J. I. T., Turco, F., Watson, S., Flemings, P. B., Davy, B., Woelz, S., Gorman, A. R., and Bialas, Jörg

Abstract

Focused gas migration through the gas hydrate stability zone in vertical gas conduits is a global phenomenon. The process can lead to concentrated gas hydrate formation and seafloor gas seepage, which influences seafloor biodiversity and ocean biogeochemistry. However, much is unknown about how gas and gas hydrate co-exist within and around gas conduits. We present seismic imaging of the gas hydrate system beneath a four-way closure anticlinal ridge at New Zealand's southern Hikurangi subduction margin. Gas has accumulated beneath the base of gas hydrate stability to a thickness of up to ∼240 m, which has ultimately led to hydraulic fracturing and propagation of a vertical gas conduit to the seafloor. Despite the existence of an array of normal faults beneath the ridge, these structures are not exploited as long-range gas flow conduits. Directly beneath the conduit, and extending upward from the regional base of gas hydrate stability, is a broad zone characterized by both negative- and positive-polarity reflections. We interpret this zone as a volume of sediment hosting both gas hydrate and free gas, that developed due to partial gas trapping beneath a mass transport deposit. Similar highly reflective zones have been identified at the bases of other gas conduits, but they are not intrinsic to all gas conduits through gas hydrate systems. We suggest that pronounced intervening sealing units within the gas hydrate stability zone determine whether or not they form.

Published
2021
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14. Paleogene seafloor spreading in the southeast Tasman Sea

Author

Wood, R., Lamarche, G., Herzer, R., Delteil, J., and Davy, B.

Subjects
Tasman Sea -- Natural history, Plate tectonics -- Research, Earth sciences
Abstract

Old and new data were integrated to surmise the Paleogene tectonic evolution of the southeast Tasman oceanic crust. Focus was on the Paleocene-Eocene plate reorganization's structural aspects and on spreading direction changes. Results show that the spreading direction change in the Tasman Sea region near the end of the Paleocene gave rise to orthogonal seafloor fabrics on the sides of the Resolution Ridge system. Such change may have been too large or too fast to have been incrementally accommodated along the margin of the Tasman-Pacific plate.

Published
1996

18. The interlinked Cenozoic evolution of ocean circulation patterns and Antarctic ice sheets from paleobathymetric grids of the Southern Ocean

Author

Hochmuth, Katharina, Gohl, Karsten, Sauermilch, Isabel, Whittaker, Joanne M., Leitchenkov, G., DeSantis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, Davy, B., Hochmuth, Katharina, Gohl, Karsten, Sauermilch, Isabel, Whittaker, Joanne M., Leitchenkov, G., DeSantis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, and Davy, B.

Published
2018

19. Paleobathymetric grids of the Cenozoic Southern Ocean - paving the way towards improved reconstructions of the Southern Ocean's past

Author

Hochmuth, Katharina, Gohl, Karsten, Leitchenkov, G., Sauermilch, Isabel, Whittaker, Joanne M., de Santis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, Davy, B., Hochmuth, Katharina, Gohl, Karsten, Leitchenkov, G., Sauermilch, Isabel, Whittaker, Joanne M., de Santis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, and Davy, B.

Published
2018

20. Paleobathymetry of the Cenozoic Southern Ocean and its various consequences

Author

Hochmuth, Katharina, Gohl, Karsten, Leitchenkov, G., Sauermilch, Isabel, Whittaker, Joanne M., de Santis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, Davy, B., Hochmuth, Katharina, Gohl, Karsten, Leitchenkov, G., Sauermilch, Isabel, Whittaker, Joanne M., de Santis, Laura, Olivio, Elisabetta, Uenzelmann-Neben, Gabriele, and Davy, B.

Published
2018

27. CHRIMP - Chatham Rise (Methane) Pockmarks

Author

Bialas, Jörg, Sarkar, Sudipta, Klaucke, Ingo, Pecher, I., Waghorn, K., Hoffmann, Jasper, Schneider von Deimling, Jens, Dannowski, Anke, Erogluer, Nur, Eckardt, Thomas, Davy, B., Coffin, R., Rose, P., Papenberg, Cord, and Koch, Stephanie

Published
2015

29. Antioxidant properties of cereal products

Author

Yu, L., Perret, J., Davy, B., Wilson, J., and Murray, C.L.

Subjects
Cereal products -- Analysis, Antioxidants -- Comparative analysis, Business, Food/cooking/nutrition
Abstract

Study of four commercial cereal products and comparison of their antioxidant properties is presented.

Published
2002

35. Hikurangi Plateau: Crustal structure, rifted formation, and Gondwana subduction history

Author

Davy, B., Hoernle, Kaj, and Werner, Reinhard

Abstract

Seismic reflection profiles across the Hikurangi Plateau Large Igneous Province and adjacent margins reveal the faulted volcanic basement and overlying Mesozoic-Cenozoic sedimentary units as well as the structure of the paleoconvergent Gondwana margin at the southern plateau limit. The Hikurangi Plateau crust can be traced 50–100 km southward beneath the Chatham Rise where subduction cessation timing and geometry are interpreted to be variable along the margin. A model fit of the Hikurangi Plateau back against the Manihiki Plateau aligns the Manihiki Scarp with the eastern margin of the Rekohu Embayment. Extensional and rotated block faults which formed during the breakup of the combined Manihiki-Hikurangi plateau are interpreted in seismic sections of the Hikurangi Plateau basement. Guyots and ridge-like seamounts which are widely scattered across the Hikurangi Plateau are interpreted to have formed at 99–89 Ma immediately following Hikurangi Plateau jamming of the Gondwana convergent margin at ∼100 Ma. Volcanism from this period cannot be separately resolved in the seismic reflection data from basement volcanism; hence seamount formation during Manihiki-Hikurangi Plateau emplacement and breakup (125–120 Ma) cannot be ruled out. Seismic reflection data and gravity modeling suggest the 20-Ma-old Hikurangi Plateau choked the Cretaceous Gondwana convergent margin within 5 Ma of entry. Subsequent uplift of the Chatham Rise and slab detachment has led to the deposition of a Mesozoic sedimentary unit that thins from ∼1 km thickness northward across the plateau. The contrast with the present Hikurangi Plateau subduction beneath North Island, New Zealand, suggests a possible buoyancy cutoff range for LIP subduction consistent with earlier modeling.

Published
2008

36. Parametric analysis of core-noise from a realistic gas-turbine combustor for cruise and take-off conditions

Author

Changxiao Shao, Davy Brouzet, Nicholas Rock, and Matthias Ihme

Subjects
Combustion noise, Indirect noise, Gas-turbine combustor, Large-eddy simulation, Fuel, TP315-360, Energy industries. Energy policy. Fuel trade, HD9502-9502.5
Abstract

Combustion noise from a realistic gas-turbine combustor geometry is investigated parametrically using a hybrid simulation framework that combines large-eddy simulation and a linearized Euler formulation. The effect of operating conditions on the relative noise-source contributions arising from direct and indirect noise is examined by considering take-off and cruise conditions. To quantify the predictions of the combustion flow field, comparisons with available experimental data for velocity and spray droplet diameter are performed. Analysis of combustion dynamics shows that tonal combustion noise from a thermoacoustic instability is present at both operating conditions, which is consistent with experimental data. The unsteady combustion and dilution are the main sources for the fluctuations of pressure, temperature and mixture composition at the combustor exit. While the thermo-chemical properties do not significantly change between the two operating conditions, the simulation results show that the level of unsteadiness in the flow field is significantly higher for the take-off condition. This leads to an overall increase in the noise emissions by up to 20 dB at take-off compared to the cruise condition. Indirect noise arising from compositional inhomogeneities is found to exceed the entropy noise for both operating conditions. Phase cancellation between composition noise and temperature-induced noise is shown to result in an overall reduction of the indirect combustion-noise emissions.

Published
2022
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37. Frontal accretion and thrust wedge evolution under very oblique plate convergence: Fiordland Basin, New Zealand

Author

Barnes, P., Davy, B., Sutherland, R., Delteil, J., Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Abstract

Basin Research, v. 14, n. 4, p. 439-466, 2002. http://dx.doi.org/10.1046/j.1365-2117.2002.00178.x; International audience

Published
2002

50. Rifting im östlichen Neuseeland und Beginn des Aufbruchs zwischen Neuseeland und der Westantarktis: Ergebnisse der Sonne-Fahrt SO 169

Author

Grobys, Jan, Gohl, Karsten, Uenzelmann-Neben, Gabriele, Davy, B., Barker, D., Deen, T., Grobys, Jan, Gohl, Karsten, Uenzelmann-Neben, Gabriele, Davy, B., Barker, D., and Deen, T.

Abstract

Die Prozesse, die zum intrakontinentalen Rifting und nachfolgenden Abbruch führen und ihn begleiten, sind weiterhin nur teilweise verstanden. Neueste plattentektonische Rekonstruktionen des Südpazifiks zeigen, daß der kretazische Abbruchprozeß von Neuseeland und der Westantarktis in sehr unterschiedlichen Phasen und Zeiten abgelaufen ist. Ein erstes Rifting zwischen dem Chatham Rise und dem östlichen Marie-Byrd-Land bzw. dem westlichen Thurston-Island-Block der Antarktis fand um 90 Ma statt (Abb. 1), nachdem vermutlich die Kollision des Hikurangi-Plateaus mit dem ehemaligen Chatham Rise den proto-pazifischen Subduktionsvorgang entlang des damaligen Nordrands von Neusee-land beendete. Das benachbarte Campbell-plateau trennte sich von Marie-Byrd-Land erst um 83 Ma. Der dazwi-schenliegende Zeitraum ist durch enorme Extensionsprozesse der neuseeländischen Kruste gekennzeichnet, die den Bountytrog und das Great South Basin als breite und tiefe Sedi-mentbecken formieren ließen.Als Teil des Projekts CAMP wird mit den während der Fahrt SO-169 (Jan./Feb. 2003, Abb. 2) gewonnenen geophysikalischen Daten der Fragestellung nachgegangen, welche Rolle die Öffnung des Bountytrogs und des Great South Basins sowie das Campbellplateau für den kontinentalen Abbruchprozeß spielten. Über beide Becken und Abschnitte des Plateaus sind sowohl reflexionsseismische als auch Weitwinkelreflexions- und Refraktionsprofile mit Ozeanbodenseismometern (OBS) vermessen worden. Die OBSe sind im Abstand von jeweils ca. 15 km zueinander entlang zweier Profile abgesetzt worden und haben Airgun-Signale im nominellen Schußabstand von 150 m registriert. Landwärts wurde das Great-South-Basin-Profil mit weiteren seismischen Registriereinheiten verlängert. Begleitet wurden alle Schiffsprofile mit Gravimetrie- und Magnetfeldmessungen. Die Auswertung der neu gewonnenen Daten wurde von weiteren, älteren reflexions-seismischen Daten, die von GNS Science zur Verfügung gestellt wurden. Infolge der Auswertung wurden

Published
2007

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