Paper List
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Autonomous Agents Coordinating Distributed Discovery Through Emergent Artifact Exchange
This paper addresses the fundamental limitation of current AI-assisted scientific research by enabling truly autonomous, decentralized investigation w...
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D-MEM: Dopamine-Gated Agentic Memory via Reward Prediction Error Routing
This paper addresses the fundamental scalability bottleneck in LLM agentic memory systems: the O(N²) computational complexity and unbounded API token ...
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Countershading coloration in blue shark skin emerges from hierarchically organized and spatially tuned photonic architectures inside skin denticles
This paper solves the core problem of how blue sharks achieve their striking dorsoventral countershading camouflage, revealing that coloration origina...
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Human-like Object Grouping in Self-supervised Vision Transformers
This paper addresses the core challenge of quantifying how well self-supervised vision models capture human-like object grouping in natural scenes, br...
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Hierarchical pp-Adic Framework for Gene Regulatory Networks: Theory and Stability Analysis
This paper addresses the core challenge of mathematically capturing the inherent hierarchical organization and multi-scale stability of gene regulator...
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Towards unified brain-to-text decoding across speech production and perception
This paper addresses the core challenge of developing a unified brain-to-text decoding framework that works across both speech production and percepti...
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Dual-Laws Model for a theory of artificial consciousness
This paper addresses the core challenge of developing a comprehensive, testable theory of consciousness that bridges biological and artificial systems...
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Pulse desynchronization of neural populations by targeting the centroid of the limit cycle in phase space
This work addresses the core challenge of determining optimal pulse timing and intensity for desynchronizing pathological neural oscillations when the...
Countershading coloration in blue shark skin emerges from hierarchically organized and spatially tuned photonic architectures inside skin denticles
City University of Hong Kong | Max Planck Institute of Colloids and Interfaces | University of Salzburg | B CUBE – Center for Molecular Bioengineering | Elasmobranch Research Belgium (ERB) | Medical University Innsbruck | AZTI, Basque Research and Technology Alliance (BRTA) | Hong Kong Polytechnic University
30秒速读
IN SHORT: This paper solves the core problem of how blue sharks achieve their striking dorsoventral countershading camouflage, revealing that coloration originates not from dermal pigments but from hierarchical photonic architectures within individual skin denticles.
核心创新
- Biology Identifies denticles as the primary optical units ('pixels') for shark skin coloration, overturning the assumption that coloration originates from underlying dermal chromatophores.
- Methodology Establishes a multi-scale correlative imaging pipeline (optical, μCT, histology, FIB-SEM, TEM) to link nanoscale crystal organization with macroscopic color gradients.
- Biology Demonstrates a spatial gradient in photonic architecture: from ordered purine-crystal stacks (blue) to disordered assemblies (white), coupled with systematic changes in chromatophore composition and pulp cavity volume (25% in blue zone vs. 17% in white zone).
主要结论
- Blue shark countershading originates from denticle-embedded photonic architectures, not dermal pigments, with pulp cavity volume decreasing from 25% (blue) to 17% (white).
- Color variation is organized hierarchically: at the microscale, blue denticles contain a tessellated reflector-absorber system (iridophores + melanophores), while white denticles lack melanophores entirely.
- At the nanoscale, ordered purine-crystal stacks (~10-60 nm features) generate narrowband blue reflection, whereas disordered assemblies produce broadband white scattering, directly linking crystal organization to optical output.
摘要: The blue shark (Prionace glauca) exhibits a striking dorsoventral color gradient, transitioning from vibrant blue dorsally to silver and white ventrally—a pattern widely interpreted as pelagic countershading. Despite its ecological significance, the physical basis of this coloration remains unresolved. Here we show that this color system does not arise from dermal chromatophores, as in most vertebrates, but from a previously unrecognised photonic architecture housed within the pulp cavity of individual dermal denticles that cover the skin. Optical imaging reveals discrete color domains within denticle crowns, while external denticle morphology remains similar across color zones. Using spectroscopy, micro-computed tomography, histology and correlative electron microscopy, we demonstrate that color variation is organized across coupled micro- and nanoscale architectures. In blue denticles, iridophores and melanophores form a densely packed tessellated reflector–absorber system within an expanded crown-restricted pulp cavity. Transition-zone denticles exhibit partial cellular layering, whereas white denticles lack melanophores and contain only reflective cells. At the nanoscale, ordered purine-crystal stacks generate narrowband blue reflection, whereas disordered assemblies produce broadband white scattering. Together, these results reveal denticles as mechanically protected optical “pixels” whose hierarchical cellular and nanocrystal organization generates the shark’s countershaded coloration.