TY - JOUR AB - Statistics of natural scenes are not uniform - their structure varies dramatically from ground to sky. It remains unknown whether these non-uniformities are reflected in the large-scale organization of the early visual system and what benefits such adaptations would confer. Here, by relying on the efficient coding hypothesis, we predict that changes in the structure of receptive fields across visual space increase the efficiency of sensory coding. We show experimentally that, in agreement with our predictions, receptive fields of retinal ganglion cells change their shape along the dorsoventral retinal axis, with a marked surround asymmetry at the visual horizon. Our work demonstrates that, according to principles of efficient coding, the panoramic structure of natural scenes is exploited by the retina across space and cell-types. AU - Gupta, Divyansh AU - Mlynarski, Wiktor F AU - Sumser, Anton L AU - Symonova, Olga AU - Svaton, Jan AU - Jösch, Maximilian A ID - 12349 JF - Nature Neuroscience SN - 1097-6256 TI - Panoramic visual statistics shape retina-wide organization of receptive fields VL - 26 ER - TY - DATA AB - Statistics of natural scenes are not uniform - their structure varies dramatically from ground to sky. It remains unknown whether these non-uniformities are reflected in the large-scale organization of the early visual system and what benefits such adaptations would confer. Here, by relying on the efficient coding hypothesis, we predict that changes in the structure of receptive fields across visual space increase the efficiency of sensory coding. We show experimentally that, in agreement with our predictions, receptive fields of retinal ganglion cells change their shape along the dorsoventral retinal axis, with a marked surround asymmetry at the visual horizon. Our work demonstrates that, according to principles of efficient coding, the panoramic structure of natural scenes is exploited by the retina across space and cell-types. AU - Gupta, Divyansh AU - Sumser, Anton L AU - Jösch, Maximilian A ID - 12370 TI - Research Data for: Panoramic visual statistics shape retina-wide organization of receptive fields ER - TY - JOUR AB - The deployment of direct formate fuel cells (DFFCs) relies on the development of active and stable catalysts for the formate oxidation reaction (FOR). Palladium, providing effective full oxidation of formate to CO2, has been widely used as FOR catalyst, but it suffers from low stability, moderate activity, and high cost. Herein, we detail a colloidal synthesis route for the incorporation of P on Pd2Sn nanoparticles. These nanoparticles are dispersed on carbon black and the obtained composite is used as electrocatalytic material for the FOR. The Pd2Sn0.8P-based electrodes present outstanding catalytic activities with record mass current densities up to 10.0 A mgPd-1, well above those of Pd1.6Sn/C reference electrode. These high current densities are further enhanced by increasing the temperature from 25 °C to 40 °C. The Pd2Sn0.8P electrode also allows for slowing down the rapid current decay that generally happens during operation and can be rapidly re-activated through potential cycling. The excellent catalytic performance obtained is rationalized using density functional theory (DFT) calculations. AU - Montaña-Mora, Guillem AU - Qi, Xueqiang AU - Wang, Xiang AU - Chacón-Borrero, Jesus AU - Martinez-Alanis, Paulina R. AU - Yu, Xiaoting AU - Li, Junshan AU - Xue, Qian AU - Arbiol, Jordi AU - Ibáñez, Maria AU - Cabot, Andreu ID - 12829 JF - Journal of Electroanalytical Chemistry SN - 1572-6657 TI - Phosphorous incorporation into palladium tin nanoparticles for the electrocatalytic formate oxidation reaction VL - 936 ER - TY - JOUR AB - We study a new discretization of the Gaussian curvature for polyhedral surfaces. This discrete Gaussian curvature is defined on each conical singularity of a polyhedral surface as the quotient of the angle defect and the area of the Voronoi cell corresponding to the singularity. We divide polyhedral surfaces into discrete conformal classes using a generalization of discrete conformal equivalence pioneered by Feng Luo. We subsequently show that, in every discrete conformal class, there exists a polyhedral surface with constant discrete Gaussian curvature. We also provide explicit examples to demonstrate that this surface is in general not unique. AU - Kourimska, Hana ID - 12764 JF - Discrete and Computational Geometry SN - 0179-5376 TI - Discrete yamabe problem for polyhedral surfaces VL - 70 ER - TY - THES AB - The extension of extremal combinatorics to the setting of exterior algebra is a work in progress that gained attention recently. In this thesis, we study the combinatorial structure of exterior algebra by introducing a dictionary that translates the notions from the set systems into the framework of exterior algebra. We show both generalizations of celebrated Erdös--Ko--Rado theorem and Hilton--Milner theorem to the setting of exterior algebra in the simplest non-trivial case of two-forms. AU - Köse, Seyda ID - 13331 SN - 2791-4585 TI - Exterior algebra and combinatorics ER - TY - JOUR AB - Animals exhibit a variety of behavioural defences against socially transmitted parasites. These defences evolved to increase host fitness by avoiding, resisting or tolerating infection. Because they can occur in both infected individuals and their uninfected social partners, these defences often have important consequences for the social group. Here, we discuss the evolution and ecology of anti-parasite behavioural defences across a taxonomically wide social spectrum, considering colonial groups, stable groups, transitional groups and solitary animals. We discuss avoidance, resistance and tolerance behaviours across these social group structures, identifying how social complexity, group composition and interdependent social relationships may contribute to the expression and evolution of behavioural strategies. Finally, we outline avenues for further investigation such as approaches to quantify group-level responses, and the connection of the physiological and behavioural response to parasites in different social contexts. AU - Stockmaier, Sebastian AU - Ulrich, Yuko AU - Albery, Gregory F. AU - Cremer, Sylvia AU - Lopes, Patricia C. ID - 12765 IS - 4 JF - Functional Ecology SN - 0269-8463 TI - Behavioural defences against parasites across host social structures VL - 37 ER - TY - JOUR AB - The celebrated Erdős–Ko–Rado theorem about the maximal size of an intersecting family of r-element subsets of was extended to the setting of exterior algebra in [5, Theorem 2.3] and in [6, Theorem 1.4]. However, the equality case has not been settled yet. In this short note, we show that the extension of the Erdős–Ko–Rado theorem and the characterization of the equality case therein, as well as those of the Hilton–Milner theorem to the setting of exterior algebra in the simplest non-trivial case of two-forms follow from a folklore puzzle about possible arrangements of an intersecting family of lines. AU - Ivanov, Grigory AU - Köse, Seyda ID - 12680 IS - 6 JF - Discrete Mathematics SN - 0012-365X TI - Erdős-Ko-Rado and Hilton-Milner theorems for two-forms VL - 346 ER - TY - JOUR AB - In the physics literature the spectral form factor (SFF), the squared Fourier transform of the empirical eigenvalue density, is the most common tool to test universality for disordered quantum systems, yet previous mathematical results have been restricted only to two exactly solvable models (Forrester in J Stat Phys 183:33, 2021. https://doi.org/10.1007/s10955-021-02767-5, Commun Math Phys 387:215–235, 2021. https://doi.org/10.1007/s00220-021-04193-w). We rigorously prove the physics prediction on SFF up to an intermediate time scale for a large class of random matrices using a robust method, the multi-resolvent local laws. Beyond Wigner matrices we also consider the monoparametric ensemble and prove that universality of SFF can already be triggered by a single random parameter, supplementing the recently proven Wigner–Dyson universality (Cipolloni et al. in Probab Theory Relat Fields, 2021. https://doi.org/10.1007/s00440-022-01156-7) to larger spectral scales. Remarkably, extensive numerics indicates that our formulas correctly predict the SFF in the entire slope-dip-ramp regime, as customarily called in physics. AU - Cipolloni, Giorgio AU - Erdös, László AU - Schröder, Dominik J ID - 12792 JF - Communications in Mathematical Physics SN - 0010-3616 TI - On the spectral form factor for random matrices VL - 401 ER - TY - JOUR AB - Given a finite set A ⊂ ℝ^d, let Cov_{r,k} denote the set of all points within distance r to at least k points of A. Allowing r and k to vary, we obtain a 2-parameter family of spaces that grow larger when r increases or k decreases, called the multicover bifiltration. Motivated by the problem of computing the homology of this bifiltration, we introduce two closely related combinatorial bifiltrations, one polyhedral and the other simplicial, which are both topologically equivalent to the multicover bifiltration and far smaller than a Čech-based model considered in prior work of Sheehy. Our polyhedral construction is a bifiltration of the rhomboid tiling of Edelsbrunner and Osang, and can be efficiently computed using a variant of an algorithm given by these authors as well. Using an implementation for dimension 2 and 3, we provide experimental results. Our simplicial construction is useful for understanding the polyhedral construction and proving its correctness. AU - Corbet, René AU - Kerber, Michael AU - Lesnick, Michael AU - Osang, Georg F ID - 12709 JF - Discrete and Computational Geometry SN - 0179-5376 TI - Computing the multicover bifiltration VL - 70 ER - TY - JOUR AB - Kleinjohann (Archiv der Mathematik 35(1):574–582, 1980; Mathematische Zeitschrift 176(3), 327–344, 1981) and Bangert (Archiv der Mathematik 38(1):54–57, 1982) extended the reach rch(S) from subsets S of Euclidean space to the reach rchM(S) of subsets S of Riemannian manifolds M, where M is smooth (we’ll assume at least C3). Bangert showed that sets of positive reach in Euclidean space and Riemannian manifolds are very similar. In this paper we introduce a slight variant of Kleinjohann’s and Bangert’s extension and quantify the similarity between sets of positive reach in Euclidean space and Riemannian manifolds in a new way: Given p∈M and q∈S, we bound the local feature size (a local version of the reach) of its lifting to the tangent space via the inverse exponential map (exp−1p(S)) at q, assuming that rchM(S) and the geodesic distance dM(p,q) are bounded. These bounds are motivated by the importance of the reach and local feature size to manifold learning, topological inference, and triangulating manifolds and the fact that intrinsic approaches circumvent the curse of dimensionality. AU - Boissonnat, Jean Daniel AU - Wintraecken, Mathijs ID - 12763 JF - Journal of Applied and Computational Topology SN - 2367-1726 TI - The reach of subsets of manifolds VL - 7 ER -