Data-efficient Neuroevolution with Kernel-Based Surrogate Models

Surrogate-assistance approaches have long been used in computationally expensive domains to improve the data-efficiency of optimization algorithms. Neuroevolution, however, has so far resisted the application of these techniques because it requires the surrogate model to make fitness predictions based on variable topologies, instead of a vector of parameters. Our main insight is that we can sidestep this problem by using kernel-based surrogate models, which require only the definition of a distance measure between individuals. Our second insight is that the well-established Neuroevolution of Augmenting Topologies (NEAT) algorithm provides a computationally efficient distance measure between dissimilar networks in the form of "compatibility distance", initially designed to maintain topological diversity. Combining these two ideas, we introduce a surrogate-assisted neuroevolution algorithm that combines NEAT and a surrogate model built using a compatibility distance kernel. We demonstrate the data-efficiency of this new algorithm on the low dimensional cart-pole swing-up problem, as well as the higher dimensional half-cheetah running task. In both tasks the surrogate-assisted variant achieves the same or better results with several times fewer function evaluations as the original NEAT.Comment: In GECCO 201

Edge theories in Projected Entangled Pair State models

We study the edge physics of gapped quantum systems in the framework of Projected Entangled Pair State (PEPS) models. We show that the effective low-energy model for any region acts on the entanglement degrees of freedom at the boundary, corresponding to physical excitations located at the edge. This allows us to determine the edge Hamiltonian in the vicinity of PEPS models, and we demonstrate that by choosing the appropriate bulk perturbation, the edge Hamiltonian can exhibit a rich phase diagram and phase transitions. While for models in the trivial phase any Hamiltonian can be realized at the edge, we show that for topological models, the edge Hamiltonian is constrained by the topological order in the bulk which can e.g. protect a ferromagnetic Ising chain at the edge against spontaneous symmetry breaking.Comment: 5 pages, 4 figure

The Cultural Grounding of Kinship

Kinship systems are conceptually grounded in culturally formulated idea-systems we refer to as kinship terminologies and through which the boundaries, form and structure of human social systems are culturally constituted. A terminology, contrary to a long-standing assumption in anthropology, is not based on a prior categorization of genealogical relations, as the latter is derived from the structural logic of the kinship terminology. The terminology structure, formally represented as an algebraic structure, can be generated from primary kin terms in accordance with a hypothesized universal theory of kinship terminology structures. Terminologies differ culturally according to the primary terms and equations used for generating them. This requires a paradigm shift from the received view of genealogy as the primary basis for kin relations to a new paradigm in which kinship incorporates both a kin term space expressed through a culturally constituted idea-system we refer to as a kinship terminology and a genealogical space constructed recursively using parent-child relations. Both of these spaces are grounded in a family space composed of parent-child, spouse and sibling positions.D’un point de vue conceptuel, les systèmes de parenté reposent sur des modes de représentation culturelle que nous appelons terminologies de parenté et à partir desquelles les limites, la forme et la structure des principes d’organisation sociale sont culturellement élaborés. Contrairement à ce que les anthropologues tiennent depuis longtemps pour acquis, une terminologie n’est pas forcément inhérente aux relations généalogiques, ces dernières découlant de la logique structurelle de la terminologie de parenté. La structure de la terminologie, représentée sous une forme algébrique, peut être produite à partir des principaux termes de parenté, suivant un principe supposé universel de structures terminologiques de la parenté. Les terminologies diffèrent, sur le plan culturel, selon les principales expressions et équations utilisées pour les élaborer. Cela implique un changement de paradigme qui nous ferait passer de la généalogie considérée comme fondement essentiel des relations de parenté à un modèle dans lequel la parenté intégrerait à la fois des termes de parenté propres à un système de représentations culturellement constitué auquel nous nous référons dans la terminologie de parenté, et une dimension généalogique élaborée de manière récursive en utilisant les relations parents/enfants. Ces deux domaines sont fondés sur un espace familial comprenant les positions de parents/enfants, conjoints, germains

Effect of Fetal Striatal and Astrocyte Transplants into Unilateral Excitotoxin-Lesioned Striatum

Studies have suggested that neurotrophic mechanisms may underlie transplant-induced functional recovery. Astrocytes have been reported to be a source of neurotrophic factors. The present study examined the possible role of cultured astrocytes in promoting recovery of apomorphine-induced rotation behavior in rats with unilateral kainic acid (KA) lesions of the striatum. Five weeks after the lesions, one group of rats received fetal striatal tissue (E17) transplants, another group received transplants of cultured astrocyte suspension, and the remaining rats received sham transplants and served as controls. Apomorphine-induced rotation behavior was tested 4 weeks after the KA lesions, and 5 and 10 weeks following the transplantation. The KA-induced rotation behavior was reduced by the striatal transplants but not by the cultured astrocyte transplants 5 and 10 weeks following the transplantation. Histochemicai analysis indicated that the striatal transplants had survived and grown and contained neurons and glia with similar morphology to those in the host brain. Immunocytochemical analysis of the astrocyte transplant sites revealed heavy glial fibrillary acidic protein and OX-42 staining in the transplant areas, suggesting that the transplanted astrocytes may have survived in the host brain. Although fetal striatal transplants can ameliorate apomorphine-induced rotation behavior, transplants of astrocytes alone may not be sufficient to reverse the functional deficits produced by KA lesions

Human phosphodiesterase 4D7 (PDE4D7) expression is increased in TMPRSS2-ERG positive primary prostate cancer and independently adds to a reduced risk of post-surgical disease progression

background: There is an acute need to uncover biomarkers that reflect the molecular pathologies, underpinning prostate cancer progression and poor patient outcome. We have previously demonstrated that in prostate cancer cell lines PDE4D7 is downregulated in advanced cases of the disease. To investigate further the prognostic power of PDE4D7 expression during prostate cancer progression and assess how downregulation of this PDE isoform may affect disease outcome, we have examined PDE4D7 expression in physiologically relevant primary human samples. methods: About 1405 patient samples across 8 publically available qPCR, Affymetrix Exon 1.0 ST arrays and RNA sequencing data sets were screened for PDE4D7 expression. The TMPRSS2-ERG gene rearrangement status of patient samples was determined by transformation of the exon array and RNA seq expression data to robust z-scores followed by the application of a threshold >3 to define a positive TMPRSS2-ERG gene fusion event in a tumour sample. results: We demonstrate that PDE4D7 expression positively correlates with primary tumour development. We also show a positive association with the highly prostate cancer-specific gene rearrangement between TMPRSS2 and the ETS transcription factor family member ERG. In addition, we find that in primary TMPRSS2-ERG-positive tumours PDE4D7 expression is significantly positively correlated with low-grade disease and a reduced likelihood of progression after primary treatment. Conversely, PDE4D7 transcript levels become significantly decreased in castration resistant prostate cancer (CRPC). conclusions: We further characterise and add physiological relevance to PDE4D7 as a novel marker that is associated with the development and progression of prostate tumours. We propose that the assessment of PDE4D7 levels may provide a novel, independent predictor of post-surgical disease progression

Three-body Faddeev Calculation for 11Li with Separable Potentials

The halo nucleus $^{11}$Li is treated as a three-body system consisting of an inert core of $^{9}$Li plus two valence neutrons. The Faddeev equations are solved using separable potentials to describe the two-body interactions, corresponding in the n-$^{9}$Li subsystem to a p$_{1/2}$ resonance plus a virtual s-wave state. The experimental $^{11}$Li energy is taken as input and the $^{9}$Li transverse momentum distribution in $^{11}$Li is studied.Comment: 6 pages, RevTeX, 1 figur