Illusions promote mating success in great bowerbirds     

Kelley LA  Endler JA 《Science (New York, N.Y.)》2012,335(6066):335-338

Sexual selection studies normally compare signal strengths, but signal components and sensory processing may interact to create misleading or attention-capturing illusions. Visual illusions can be produced by altering object and scene geometry in ways that trick the viewer when seen from a particular direction. Male great bowerbirds actively maintain size-distance gradients of objects on their bower courts that create forced-perspective illusions for females viewing their displays from within the bower avenue. We show a significant relationship between mating success and the female's view of the gradient; this view explains substantially more variance in mating success than the strength of the gradients. Illusions may be widespread in other animals because males of most species display to females with characteristic orientation and distance, providing excellent conditions for illusions.  相似文献   

Neural representations of location composed of spatially periodic bands     

J Krupic  N Burgess  J O'Keefe 《Science (New York, N.Y.)》2012,337(6096):853-857

The mammalian hippocampal formation provides neuronal representations of environmental location, but the underlying mechanisms are poorly understood. Here, we report a class of cells whose spatially periodic firing patterns are composed of plane waves (or bands) drawn from a discrete set of orientations and wavelengths. The majority of cells recorded in parasubicular and medial entorhinal cortices of freely moving rats belonged to this class and included grid cells, an important subset that corresponds to three bands at 60° orientations and has the most stable firing pattern. Occasional changes between hexagonal and nonhexagonal patterns imply a common underlying mechanism. Our results indicate a Fourier-like spatial analysis underlying neuronal representations of location, and suggest that path integration is performed by integrating displacement along a restricted set of directions.  相似文献   

Anthropology. Absolute dating of cave art     

Hellstrom J 《Science (New York, N.Y.)》2012,336(6087):1387-1388

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GBP5 promotes NLRP3 inflammasome assembly and immunity in mammals     

Shenoy AR  Wellington DA  Kumar P  Kassa H  Booth CJ  Cresswell P  MacMicking JD 《Science (New York, N.Y.)》2012,336(6080):481-485

Inflammasomes are sensory complexes that alert the immune system to the presence of infection or tissue damage. These complexes assemble NLR (nucleotide binding and oligomerization, leucine-rich repeat) or ALR (absent in melanoma 2-like receptor) proteins to activate caspase-1 cleavage and interleukin (IL)-1β/IL-18 secretion. Here, we identified a non-NLR/ALR human protein that stimulates inflammasome assembly: guanylate binding protein 5 (GBP5). GBP5 promoted selective NLRP3 inflammasome responses to pathogenic bacteria and soluble but not crystalline inflammasome priming agents. Generation of Gbp5(-/-) mice revealed pronounced caspase-1 and IL-1β/IL-18 cleavage defects in vitro and impaired host defense and Nlrp3-dependent inflammatory responses in vivo. Thus, GBP5 serves as a unique rheostat for NLRP3 inflammasome activation and extends our understanding of the inflammasome complex beyond its core machinery.  相似文献   

Public health and biosecurity. Adaptations of avian flu virus are a cause for concern     

Berns KI  Casadevall A  Cohen ML  Ehrlich SA  Enquist LW  Fitch JP  Franz DR  Fraser-Liggett CM  Grant CM  Imperiale MJ  Kanabrocki J  Keim PS  Lemon SM  Levy SB  Lumpkin JR  Miller JF  Murch R  Nance ME  Osterholm MT  Relman DA  Roth JA  Vidaver AK 《Science (New York, N.Y.)》2012,335(6069):660-661

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Comment on "Nonreciprocal light propagation in a silicon photonic circuit"     

Fan S  Baets R  Petrov A  Yu Z  Joannopoulos JD  Freude W  Melloni A  Popović M  Vanwolleghem M  Jalas D  Eich M  Krause M  Renner H  Brinkmeyer E  Doerr CR 《Science (New York, N.Y.)》2012,335(6064):38; author reply 38

We show that the structure demonstrated by Feng et al. (Reports, 5 August 2011, p. 729) cannot enable optical isolation because it possesses a symmetric scattering matrix. Moreover, one cannot construct an optical isolator by incorporating this structure into any system as long as the system is linear and time-independent and is described by materials with a scalar dielectric function.  相似文献   

PrP antibodies do not trigger mouse hippocampal neuron apoptosis     

Klöhn PC  Farmer M  Linehan JM  O'Malley C  Fernandez de Marco M  Taylor W  Farrow M  Khalili-Shirazi A  Brandner S  Collinge J 《Science (New York, N.Y.)》2012,335(6064):52

Intraperitoneal administration of ICSM18 and 35, monoclonal antibodies against prion protein (PrP), has been shown to significantly delay the onset of prion disease in mice, and humanized versions are candidate therapeutics for prion and Alzheimer's diseases. However, a previous report of severe and widespread apoptosis after intracerebral injection of anti-PrP monoclonal antibodies raised concerns about such therapy and led to an influential model of prion neurotoxicity via cross-linking of cell surface PrP by disease-related PrP aggregates. In extensive studies including ICSM18 and 35, fully humanized ICSM18, and the previously reported proapoptotic antibodies, we found no evidence of apoptosis, thereby questioning this model of prion neurotoxicity.  相似文献   

Climate change. Regional sea-level projection     

Willis JK  Church JA 《Science (New York, N.Y.)》2012,336(6081):550-551

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The structures of COPI-coated vesicles reveal alternate coatomer conformations and interactions     

Faini M  Prinz S  Beck R  Schorb M  Riches JD  Bacia K  Brügger B  Wieland FT  Briggs JA 《Science (New York, N.Y.)》2012,336(6087):1451-1454

Transport between compartments of eukaryotic cells is mediated by coated vesicles. The archetypal protein coats COPI, COPII, and clathrin are conserved from yeast to human. Structural studies of COPII and clathrin coats assembled in vitro without membranes suggest that coat components assemble regular cages with the same set of interactions between components. Detailed three-dimensional structures of coated membrane vesicles have not been obtained. Here, we solved the structures of individual COPI-coated membrane vesicles by cryoelectron tomography and subtomogram averaging of in vitro reconstituted budding reactions. The coat protein complex, coatomer, was observed to adopt alternative conformations to change the number of other coatomers with which it interacts and to form vesicles with variable sizes and shapes. This represents a fundamentally different basis for vesicle coat assembly.  相似文献   

Dislocation damping and anisotropic seismic wave attenuation in Earth's upper mantle     

Farla RJ  Jackson I  Fitz Gerald JD  Faul UH  Zimmerman ME 《Science (New York, N.Y.)》2012,336(6079):332-335

Crystal defects form during tectonic deformation and are reactivated by the shear stress associated with passing seismic waves. Although these defects, known as dislocations, potentially contribute to the attenuation of seismic waves in Earth's upper mantle, evidence for dislocation damping from laboratory studies has been circumstantial. We experimentally determined the shear modulus and associated strain-energy dissipation in pre-deformed synthetic olivine aggregates under high pressures and temperatures. Enhanced high-temperature background dissipation occurred in specimens pre-deformed by dislocation creep in either compression or torsion, the enhancement being greater for prior deformation in torsion. These observations suggest the possibility of anisotropic attenuation in relatively coarse-grained rocks where olivine is or was deformed at relatively high stress by dislocation creep in Earth's upper mantle.  相似文献