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Do female hyaenas choose mates based on tenure?

Nature 454, E1 (2008). doi:10.1038/nature07122

Authors: Russell C. Van Horn, Heather E. Watts & Kay E. Holekamp

Arising from: O. P. Höner et al.Nature448, 798–801 (2007); Höner et al.replyIn their investigation into whether female mate-choice drives male dispersal, Höner et al. argue that female spotted hyaenas (Crocuta crocuta) prefer mates whose tenure in the social group is less than the females’ age, to avoid paternal incest, and suggest that male dispersal reflects this preference. However, we are not persuaded that females choose mates on the basis of tenure because Höner et al. overlook the alternative hypothesis that dispersal status itself is important in female mate-choice, such that females prefer immigrants over natal males. Like mate-choice based on tenure, choice based on dispersal status reduces the risk of incest.

Höner et al. reply

Nature 454, E2 (2008). doi:10.1038/nature07123

Authors: Oliver P. Höner, Bettina Wachter, Marion L. East, W. Jürgen Streich, Kerstin Wilhelm, Terry Burke & Heribert Hofer

Replying to: R. C. Van Horn, H. E. Watts & K. E. Holekamp Nature454, 10.1038/nature07122 (2008)We demonstrated that female mate-choice, rather than male inbreeding avoidance, resources or male–male competition, drives male-biased dispersal in spotted hyaenas (Crocuta crocuta). We further showed that females use two simple rules based on male tenure to choose their sires, and that males gain substantial fitness benefits by responding to these preferences. Van Horn et al. accept our principal conclusions but claim that females base mate-choice on dispersal status rather than tenure. Their argument overlooks the fact that at least one of the two female mate-choice rules cannot be explained by dispersal status, and it is based on statistical analyses and a selection of males that we consider inappropriate for tests of female mate preference.

Structure of the Ebola virus glycoprotein bound to an antibody from a human survivor

Nature 454, 177 (2008). doi:10.1038/nature07082

Authors: Jeffrey E. Lee, Marnie L. Fusco, Ann J. Hessell, Wendelien B. Oswald, Dennis R. Burton & Erica Ollmann Saphire

Ebola virus (EBOV) entry requires the surface glycoprotein (GP) to initiate attachment and fusion of viral and host membranes. Here we report the crystal structure of EBOV GP in its trimeric, pre-fusion conformation (GP1+GP2) bound to a neutralizing antibody, KZ52, derived from a human survivor

Rotational breakup as the origin of small binary asteroids

Nature 454, 188 (2008). doi:10.1038/nature07078

Authors: Kevin J. Walsh, Derek C. Richardson & Patrick Michel

Asteroids with satellites are observed throughout the Solar System, from subkilometre near-Earth asteroid pairs to systems of large and distant bodies in the Kuiper belt. The smallest and closest systems are found among the near-Earth and small inner main-belt asteroids, which typically have rapidly rotating primaries and close secondaries on circular orbits. About 15 per cent of near-Earth and main-belt asteroids with diameters under 10 km have satellites. The mechanism that forms such similar binaries in these two dynamically different populations was hitherto unclear. Here we show that these binaries are created by the slow spinup of a ‘rubble pile’ asteroid by means of the thermal YORP (Yarkovsky–O’Keefe–Radzievskii–Paddack) effect. We find that mass shed from the equator of a critically spinning body accretes into a satellite if the material is collisionally dissipative and the primary maintains a low equatorial elongation. The satellite forms mostly from material originating near the primary’s surface and enters into a close, low-eccentricity orbit. The properties of binaries produced by our model match those currently observed in the small near-Earth and main-belt asteroid populations, including 1999 KW4 (refs 3, 4).

Volatile content of lunar volcanic glasses and the presence of water in the Moon’s interior

Nature 454, 192 (2008). doi:10.1038/nature07047

Authors: Alberto E. Saal, Erik H. Hauri, Mauro L. Cascio, James A. Van Orman, Malcolm C. Rutherford & Reid F. Cooper

The Moon is generally thought to have formed and evolved through a single or a series of catastrophic heating events, during which most of the highly volatile elements were lost. Hydrogen, being the lightest element, is believed to have been completely lost during this period. Here we make use of considerable advances in secondary ion mass spectrometry to obtain improved limits on the indigenous volatile (CO2, H2O, F, S and Cl) contents of the most primitive basalts in the Moon—the lunar volcanic glasses. Although the pre-eruptive water content of the lunar volcanic glasses cannot be precisely constrained, numerical modelling of diffusive degassing of the very-low-Ti glasses provides a best estimate of 745 p.p.m. water, with a minimum of 260 p.p.m. at the 95 per cent confidence level. Our results indicate that, contrary to prevailing ideas, the bulk Moon might not be entirely depleted in highly volatile elements, including water. Thus, the presence of water must be considered in models constraining the Moon’s formation and its thermal and chemical evolution.

Quadrupole transitions revealed by Borrmann spectroscopy

Nature 454, 196 (2008). doi:10.1038/nature07099

Authors: Robert F. Pettifer, Stephen P. Collins & David Laundy

The Borrmann effect—a dramatic increase in transparency to X-ray beams—is observed when X-rays satisfying Bragg’s law diffract through a perfect crystal. The minimization of absorption seen in the Borrmann effect has been explained by noting that the electric field of the X-ray beam approaches zero amplitude at the crystal planes, thus avoiding the atoms. Here we show experimentally that under conditions of absorption suppression, the weaker electric quadrupole absorption transitions are effectively enhanced to such a degree that they can dominate the absorption spectrum. This effect can be exploited as an atomic spectroscopy technique; we show that quadrupole transitions give rise to additional structure at the L1, L2 and L3 absorption edges of gadolinium in gadolinium gallium garnet, which mark the onset of excitations from 2s, 2p1/2 and 2p3/2 atomic core levels, respectively. Although the Borrmann effect served to underpin the development of the theory of X-ray diffraction, this is potentially the most important experimental application of the phenomenon since its first observation seven decades ago. Identifying quadrupole features in X-ray absorption spectroscopy is central to the interpretation of ‘pre-edge’ spectra, which are often taken to be indicators of local symmetry, valence and atomic environment. Quadrupolar absorption isolates states of different symmetries to that of the dominant dipole spectrum, and typically reveals orbitals that dominate the electronic ground-state properties of lanthanides and 3d transition metals, including magnetism. Results from our Borrmann spectroscopy technique feed into contemporary discussions regarding resonant X-ray diffraction and the nature of pre-edge lines identified by inelastic X-ray scattering. Furthermore, because the Borrmann effect has been observed in photonic materials, it seems likely that the quadrupole enhancement reported here will play an important role in modern optics.

A multi-component Fermi surface in the vortex state of an underdoped high-Tc superconductor

Nature 454, 200 (2008). doi:10.1038/nature07095

Authors: Suchitra E. Sebastian, N. Harrison, E. Palm, T. P. Murphy, C. H. Mielke, Ruixing Liang, D. A. Bonn, W. N. Hardy & G. G. Lonzarich

To understand the origin of superconductivity, it is crucial to ascertain the nature and origin of the primary carriers available to participate in pairing. Recent quantum oscillation experiments on high-transition-temperature (high-Tc) copper oxide superconductors have revealed the existence of a Fermi surface akin to that in normal metals, comprising fermionic carriers that undergo orbital quantization. The unexpectedly small size of the observed carrier pocket, however, leaves open a variety of possibilities for the existence or form of any underlying magnetic order, and its relation to d-wave superconductivity. Here we report experiments on quantum oscillations in the magnetization (the de Haas-van Alphen effect) in superconducting YBa2Cu3O6.51 that reveal more than one carrier pocket. In particular, we find evidence for the existence of a much larger pocket of heavier mass carriers playing a thermodynamically dominant role in this hole-doped superconductor. Importantly, characteristics of the multiple pockets within this more complete Fermi surface impose constraints on the wavevector of any underlying order and the location of the carriers in momentum space. These constraints enable us to construct a possible density-wave model with spiral or related modulated magnetic order, consistent with experimental observations.

Preseismic velocity changes observed from active source monitoring at the Parkfield SAFOD drill site

Nature 454, 204 (2008). doi:10.1038/nature07111

Authors: Fenglin Niu, Paul G. Silver, Thomas M. Daley, Xin Cheng & Ernest L. Majer

Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. One approach is to exploit the stress dependence of seismic wave velocity, and we have investigated this in an active source cross-well experiment at the San Andreas Fault Observatory at Depth (SAFOD) drill site. Here we show that stress changes are indeed measurable using this technique. Over a two-month period, we observed an excellent anti-correlation between changes in the time required for a shear wave to travel through the rock along a fixed pathway (a few microseconds) and variations in barometric pressure. We also observed two large excursions in the travel-time data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. The two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.

The evolutionary origin of flatfish asymmetry

Nature 454, 209 (2008). doi:10.1038/nature07108

Authors: Matt Friedman

All adult flatfishes (Pleuronectiformes), including the gastronomically familiar plaice, sole, turbot and halibut, have highly asymmetrical skulls, with both eyes placed on one side of the head. This arrangement, one of the most extraordinary anatomical specializations among vertebrates, arises through migration of one eye during late larval development. Although the transformation of symmetrical larvae into asymmetrical juveniles is well documented, the evolutionary origins of flatfish asymmetry are uncertain because there are no transitional forms linking flatfishes with their symmetrical relatives. The supposed inviability of such intermediates gave pleuronectiforms a prominent role in evolutionary debates, leading to attacks on natural selection and arguments for saltatory change. Here I show that Amphistium and the new genus Heteronectes, both extinct spiny-finned fishes from the Eocene epoch of Europe, are the most primitive pleuronectiforms known. The orbital region of the skull in both taxa is strongly asymmetrical, as in living flatfishes, but these genera retain many primitive characters unknown in extant forms. Most remarkably, orbital migration was incomplete in Amphistium and Heteronectes, with eyes remaining on opposite sides of the head in post-metamorphic individuals. This condition is intermediate between that in living pleuronectiforms and the arrangement found in other fishes. Amphistium and Heteronectes indicate that the evolution of the profound cranial asymmetry of extant flatfishes was gradual in nature.

Social diversity promotes the emergence of cooperation in public goods games

Nature 454, 213 (2008). doi:10.1038/nature06940

Authors: Francisco C. Santos, Marta D. Santos & Jorge M. Pacheco

Humans often cooperate in public goods games and situations ranging from family issues to global warming. However, evolutionary game theory predicts that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments. Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects, in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution, cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment. Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.

Neurophysiology: Sensing temperature without ion channels

Nature 454, 246 (2008). doi:10.1038/nature07133

Author: Brandon R. Brown

Nature421, 495 (2003)My Brief Communication about thermoelectricity in shark gels neglected a systematic effect of surface electrochemistry: electrode potentials vary with temperature in electrolyte solutions. However, silver leads in sea water and accepted values for likely electrode reactions

An extremely luminous X-ray outburst at the birth of a supernova

Nature 454, 246 (2008). doi:10.1038/nature07134

Authors: A. M. Soderberg, E. Berger, K. L. Page, P. Schady, J. Parrent, D. Pooley, X.-Y. Wang, E. O. Ofek, A. Cucchiara, A. Rau, E. Waxman, J. D. Simon, D. C.-J. Bock, P. A. Milne, M. J. Page, J. C. Barentine, S. D. Barthelmy, A. P. Beardmore, M. F. Bietenholz, P. Brown, A. Burrows, D. N. Burrows, G. Bryngelson, S. B. Cenko, P. Chandra, J. R. Cummings, D. B. Fox, A. Gal-Yam, N. Gehrels, S. Immler, M. Kasliwal, A. K. H. Kong, H. A. Krimm, S. R. Kulkarni, T. J. Maccarone, P. Mészáros, E. Nakar, P. T. O’Brien, R. A. Overzier, M. de Pasquale, J. Racusin, N. Rea & D. G. York

Nature453, 469–474 (2008)In this Article, the surname of co-author G. Bryngelson was mis-spelled as G. Byrngelson.

Making the paper: Erica Ollmann Saphire

Nature 454, x (2008). doi:10.1038/7201xa

Structure reveals Ebola virus' strengths and weaknesses.

Abstractions

Nature 454, x (2008). doi:10.1038/7201xb

First authorPredicting earthquakes has proved an elusive goal for seismologists, in part because direct measurements from deep inside faults have been lacking. California's San Andreas Fault Observatory at Depth (SAFOD) site now allows scientists deep access to the world's most-instrumented section of fault. There,

From the blogosphere

Nature 454, x (2008). doi:10.1038/7201xc

With the provocative title “The end of theory”, an essay in Wired magazine on 23 June argues that, with the advent of huge datasets and Google-like algorithms, the scientific method has become obsolete.Inevitably, this view has stimulated responses in the scientific blogosphere, not

The long war against flu

Nature 454, 137 (2008). doi:10.1038/454137a

That the H5N1 strain of bird flu has not yet caused a pandemic is no cause for complacency. Preparations for the inevitable must be redoubled to mitigate the potential devastation.

An unnecessary battle

Nature 454, 137 (2008). doi:10.1038/454137b

Neuroscientists and geneticists don't need to be at loggerheads over the biology of mental disorders.

A social contract

Nature 454, 138 (2008). doi:10.1038/454138a

Efforts to inform US military policy with insights from the social sciences could be a win–win approach.

Climate science: A watery carbon bank

Nature 454, 140 (2008). doi:10.1038/454140a

Ecosystems11, 643–653 (2008)Dead wood can persist for more than a hundred times longer in rivers and floodplains than on land, sequestering carbon for centuries and even millennia, according to Richard Guyette of the University of Missouri in Columbia and his colleagues.Although

Neuroscience: Rewiring the brain

Nature 454, 140 (2008). doi:10.1038/454140b

J. Neurosci.28, 6592—6606 (2008)The brain can recover so well from a stroke that initially paralysed limbs can be moved again. Scientists have discovered how this happens at the level of individual neurons.Timothy Murphy and Ian Winship of the University of British