Wagner R.H., Helfenstein F. & Danchin E. (2004). Female choice of young sperm in a genetically monogamous bird. Proc. Biol. Sci., 271(Suppl 4).
Abstract: When females copulate with multiple males the potential exists for female sperm choice. Females may increase the probability of being fertilized by preferred males by selectively retaining their sperm while ejecting the sperm of unfavoured males. An alternative criterion to male quality for female sperm choice may be sperm age because old sperm degrade and can lead to zygote death or unhealthy offspring. Here, we report that in a genetically monogamous bird, the black-legged kittiwake Rissa tridactyla, females eject their mates' sperm according to when the copulations were performed. Following copulations that were performed approximately two weeks before egg laying, females ejected inseminations at high frequencies while retaining inseminations that occurred soon before laying. Females that suffered hatching failure had ejected sperm from early copulations less than half as frequently as females whose entire clutches hatched. Furthermore, chicks that hatched from eggs fertilized by old sperm were in poor condition relative to those fertilized by young sperm. These findings support the 'young sperm' hypothesis, which predicts that females choose fresh sperm to avoid reproductive failure and are the first to show intra-male sperm choice by females.
Programme: 429
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Trampert, J.; Snieder, R. (1996). Model Estimations Biased by Truncated Expansions: Possible Artifacts in Seismic Tomography. Science, 271(5253), 1257–1260.
Abstract: In most linear imaging problems, where the model to be sought is expanded in a set of basis functions, it is common practice to truncate the set at a certain (arbitrary) level. The solution then depends on the chosen parameterization, and neglected basis functions may leak into the solution to produce artifacts in the retrieved model. An unbiased estimate of the coefficients of the true model may be obtained in the chosen finite basis set ; here, a method to suppress leakage is illustrated on an example of global seismic tomography.
Keywords: seismology ; tomography ; errors ; mathematical models ; methods ; inverse problem ; elastic waves ; Rayleigh waves ; algorithms
Programme: 133
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Barbraud C. & Weimerskirch H. (2003). Climate and density shape population dynamics of a marine top predator. Proc. Roy. Soc. Lond., 270, 2111–2116.
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Davail Sfeller G., Narin X. & Gerday C. (1994). Cold Adaptation of Proteins. Purification, characterization, and sequence of the heat-labile subtilisin from the Antarctic psychrophile bacilus TA41. J. Biol. Chem., 269(26), 17448–17453.
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. (2008). Abrupt climate changes for Iceland during the last millennium: evidence from high resolution sea ice reconstructions. Earth Planet. Sci. Lett., 269(3-4), 565–569.
Abstract: A high resolution account of Icelandic sea ice over the last millennium has been constructed using a novel proxy based on the presence in sediments of a biomarker (IP25) produced by sea ice algae. Comparison with historical sea ice records demonstrates a strong correlation between documented sea ice occurrences and the IP25 proxy. An excellent agreement is also observed between the IP25 record and a diatom-based sea surface temperature reconstruction obtained from the same core and the Crowley and Lowery Northern Hemisphere temperature reconstruction. Using this approach, we provide new historical sea ice data for periods where records are scarce or absent and evidence for abrupt changes to sea ice and/or climate conditions around Iceland during the Little Ice Age.
Programme: 452
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Marino F., G. Calzolai, S. Caporali, E. Castellano, M. Chiari, F. Lucarelli, V. Maggi, S. Nava, M. Sala, R. Udisti. (2008). PIXE and PIGE techniques for the analysis of Antarctic ice dust and continental sediments. Nuclear instruments and methods in physics research b, 266, 2396–2400.
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Yoda K. & Ropert-Coudert Y. (2004). Decision-rules for leaping penguins. J. Zool. (Lond.), 263.
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Raynaud D, V Lipenkov, B Lemieux-Dudon, P Duval, M-F Loutre, N Lhomme. (2007). The local insolation signature of air content in Antarcticice. A new step toward an absolute dating of ice records. Earth Planet. Sci. Lett., 261.
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. (2007). Magnetic anomaly map of the world: merging satellite, airborne, marine and ground-based magnetic sets. Earth Planet. Sci. Lett., 260, 56–71.
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Craig D.A., Currie D.C. & Vernon P. (2003). Crozetia Davies (Diptera: Simuliidae): redescription of Cr. crozetensis, Cr. seguyi, number of larval instars, phylogenetic relationships and historical biogeography. Zootaxa, 259, 1–39.
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