Results for "C. Adami"

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Evolutionary Learning in the 2D Artificial Life System "Avida"May 16 1994We present a new tierra-inspired artificial life system with local interactions and two-dimensional geometry, based on an update mechanism akin to that of 2D cellular automata. We find that the spatial geometry is conducive to the development of diversity ... More
Abundance Distributions in Artificial Life and Stochastic Models: "Age and Area" revisitedMar 29 1995Using an artificial system of self-replicating strings, we show a correlation between the age of a genotype and its abundance that reflects a punctuated rather than gradual picture of evolution, as suggested long ago by Willis. In support of this correlation, ... More
Diffuse light in the young cluster of galaxies CL J1449+0856 at z=2.07Dec 26 2012Cluster properties do not seem to be changing significantly during their mature evolution phase, for example they do not seem to show strong dynamical evolution at least up to z~0.5, their galaxy red sequence is already in place at least up to z$\sim$1.2, ... More
Self-organized Criticality in Living SystemsJan 27 1994We suggest that ensembles of self-replicating entities such as biological systems naturally evolve into a self-organized critical state in which fluctuations, as well as waiting-times between phase transitions are distributed according to a 1/f power ... More
Ab Initio Modeling of Ecosystems with Artificial LifeSep 22 2002Artificial Life provides the opportunity to study the emergence and evolution of simple ecosystems in real time. We give an overview of the advantages and limitations of such an approach, as well as its relation to individual-based modeling techniques. ... More
Constrained energy minimization and orbital stability for the NLS equation on a star graphNov 07 2012We consider a nonlinear Schr\"odinger equation with focusing nonlinearity of power type on a star graph ${\mathcal G}$, written as $ i \partial_t \Psi (t) = H \Psi (t) - |\Psi (t)|^{2\mu}\Psi (t)$, where $H$ is the selfadjoint operator which defines the ... More
Leggett-Garg inequalities cannot be violated in quantum measurementsAug 08 2019Aug 09 2019Leggett and Garg derived inequalities that probe the boundaries of classical and quantum physics by putting limits on the properties that classical objects can have. Historically, it has been suggested that Leggett-Garg inequalities are easily violated ... More
The use of Minimal Spanning Tree to characterize the 2D cluster galaxy distributionJul 28 1998We use the Minimal Spanning Tree to characterize the aggregation level of given sets of points. We test 3 distances based on the histogram of the MST edges to discriminate between the distributions. We calibrate the method by using artificial sets following ... More
Uncertainties on Clusters of Galaxies DistancesJul 18 2000We investigate in this paper the error on the cluster redshift estimate as a function of: (1) the number of galaxy structures along the line of sight; (2) the morphology of the clusters (regular/substructures); (3) the nature of the observed galaxies ... More
Group analysis in the SSRS2 catalogOct 31 2001We present an automated method to detect populations of groups in galaxy redshift catalogs. This method uses both analysis of the redshift distribution along lines of sight in fixed cells to detect elementary structures and a friend-of-friend algorithm ... More
Shared information between residues is sufficient to detect pair-wise epistasis in a proteinNov 12 2016In a comment on our manuscript "Strong selection significantly increases epistatic interactions in the long-term evolution of a protein", Dr. Crona challenges our assertion that shared entropy (that is, information) between two residues implies epistasis ... More
Prolegomena to a non-equilibrium quantum statistical mechanicsApr 01 1999We suggest that the framework of quantum information theory, which has been developing rapidly in recent years due to intense activity in quantum computation and quantum communication, is a reasonable starting point to study non-equilibrium quantum statistical ... More
Entropic Bell InequalitiesAug 29 1996Feb 12 1997We derive entropic Bell inequalities from considering entropy Venn diagrams. These entropic inequalities, akin to the Braunstein-Caves inequalities, are violated for a quantum mechanical Einstein-Podolsky-Rosen pair, which implies that the conditional ... More
Negative entropy and information in quantum mechanicsDec 19 1995Oct 30 1997A framework for a quantum mechanical information theory is introduced that is based entirely on density operators, and gives rise to a unified description of classical correlation and quantum entanglement. Unlike in classical (Shannon) information theory, ... More
Black holes are almost optimal quantum clonersJan 11 2006Apr 15 2015If black holes were able to clone quantum states, a number of paradoxes in black hole physics would disappear. However, the linearity of quantum mechanics forbids exact cloning of quantum states. Here we show that black holes indeed clone incoming quantum ... More
Accessible information in quantum measurementNov 19 1996The amount of information that can be accessed via measurement of a quantum system prepared in different states is limited by the Kholevo bound. We present a simple proof of this theorem and its extension to sequential measurements based on the properties ... More
On the von Neumann capacity of noisy quantum channelsSep 27 1996Jun 03 1997We discuss the capacity of quantum channels for information transmission and storage. Quantum channels have dual uses: they can be used to transmit known quantum states which code for classical information, and they can be used in a purely quantum manner, ... More
Development and Evolution of Neural Networks in an Artificial ChemistryJul 17 1998We present a model of decentralized growth for Artificial Neural Networks (ANNs) inspired by the development and the physiology of real nervous systems. In this model, each individual artificial neuron is an autonomous unit whose behavior is determined ... More
What information theory can tell us about quantum realityJun 14 1998An investigation of Einstein's ``physical'' reality and the concept of quantum reality in terms of information theory suggests a solution to quantum paradoxes such as the Einstein-Podolsky-Rosen (EPR) and the Schroedinger-cat paradoxes. Quantum reality, ... More
Physical Complexity of Symbolic SequencesMay 29 1996Apr 17 1999A practical measure for the complexity of sequences of symbols (``strings'') is introduced that is rooted in automata theory but avoids the problems of Kolmogorov-Chaitin complexity. This physical complexity can be estimated for ensembles of sequences, ... More
Quantum Mechanics of MeasurementMay 03 1996Feb 12 1997An analysis of quantum measurement is presented that relies on an information-theoretic description of quantum entanglement. In a consistent quantum information theory of entanglement, entropies (uncertainties) conditional on measurement outcomes can ... More
Quantum computation with linear opticsJun 14 1998We present a constructive method to translate small quantum circuits into their optical analogues, using linear components of present-day quantum optics technology only. These optical circuits perform precisely the computation that the quantum circuits ... More
Darwinian Evolution of Cooperation via Punishment in the "Public Goods" GameJun 15 2010The evolution of cooperation has been a perennial problem for evolutionary biology because cooperation is undermined by selfish cheaters (or "free riders") that profit from cooperators but do not invest any resources themselves. In a purely "selfish" ... More
Evolution of complex modular biological networksMay 31 2007Dec 18 2007Biological networks have evolved to be highly functional within uncertain environments while remaining extremely adaptable. One of the main contributors to the robustness and evolvability of biological networks is believed to be their modularity of function, ... More
The cluster Abell 780: an optical viewJul 30 2009The Abell 780 cluster, better known as the Hydra A cluster, has been thouroughly analyzed in X-rays. However, little is known on its optical properties. We derive the galaxy luminosity function (GLF) in this apparently relaxed cluster, and search for ... More
Count laws and projection effects in clusters of galaxiesFeb 27 1998We show that a 2D projection is representative of its corresponding 3D distribution at a confidence level of 90 % if it follows a King profile and if we consider the whole spatial distribution. The level is significantly lower and not decisive in the ... More
The isolated fossil group RXJ1119.7+2126Mar 13 2007Fossil groups are galaxy structures that probably underwent a nearly complete fusion of all intermediate magnitude galaxies into a single large central dominant galaxy. However, the formation and evolution processes of these structures are still not well ... More
Evolution of Biological ComplexityMay 26 2000In order to make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic ... More
Segregations in clusters of galaxiesSep 26 1997We analyse a sample of about 2000 galaxies in 40 regular clusters, to look for evidence of segregation with respect to galaxy luminosities and morphological types. We find evidence of luminosity segregation for galaxies brighter than $M_R < -21.5$, i.e. ... More
Cluster luminosity function and n^th ranked magnitude as a distance indicatorJun 11 1998We define here a standard candle to determine the distance of clusters of galaxies and to investigate their peculiar velocities by using the n^{th} rank galaxy (magnitude m$_n$). We address the question of the universality of the luminosity function for ... More
Darwin inside the machines: Malware evolution and the consequences for computer securityNov 10 2011Recent advances in anti-malware technologies have steered the security industry away from maintaining vast signature databases and into newer defence technologies such as behaviour blocking, application whitelisting and others. Most would agree that the ... More
Selective pressures on genomes in molecular evolutionJan 15 2003We describe the evolution of macromolecules as an information transmission process and apply tools from Shannon information theory to it. This allows us to isolate three independent, competing selective pressures that we term compression, transmission, ... More
Central Matter Distributions in Rich Clusters of Galaxies from z~0 to z~0.5Feb 08 2001We have analyzed the galaxy number density and luminosity density profiles of rich clusters of galaxies from redshifts z=0 to z=0.5. We show that the luminosity profile computed with bright galaxies is significantly cusped in the center of the clusters, ... More
Evolutionary game theory using agent-based methodsApr 03 2014Aug 31 2016Evolutionary game theory is a successful mathematical framework geared towards understanding the selective pressures that affect the evolution of the strategies of agents engaged in interactions with potential conflicts. While a mathematical treatment ... More
The structure of evolved representations across different substrates for artificial intelligenceApr 05 2018Artificial neural networks (ANNs), while exceptionally useful for classification, are vulnerable to misdirection. Small amounts of noise can significantly affect their ability to correctly complete a task. Instead of generalizing concepts, ANNs seem to ... More
Optical Simulation of Quantum LogicJun 12 1997A systematic method for simulating small-scale quantum circuits by use of linear optical devices is presented. It relies on the representation of several quantum bits by a single photon, and on the implementation of universal quantum gates using simple ... More
Optical and X-ray analysis of the cluster of galaxies Abell 496Feb 29 2000We present a detailed analysis of the cluster of galaxies \a4. The optical data include a redshift catalogue of 466 galaxies, out of which 274 belong to the main cluster and a CCD photometric catalogue in a much smaller region, with 239 and 610 galaxies ... More
The link between brightest cluster galaxy properties and large scale extensions of 38 DAFT/FADA and CLASH clusters in the redshift range 0.2<z<0.9Dec 10 2018Dec 18 2018In the context of large scale structure formation, clusters of galaxies are located at the nodes of the cosmic web, and continue to accrete galaxies and groups along filaments. They show sometimes a very large extension and a preferential direction. Brightest ... More
Origin of life in a digital microcosmJan 15 2017While all organisms on Earth descend from a common ancestor, there is no consensus on whether the origin of this ancestral self-replicator was a one-off event or whether it was only the final survivor of multiple origins. Here we use the digital evolution ... More
Quantum conditional operator and a criterion for separabilityOct 01 1997Oct 02 1997We analyze the properties of the conditional amplitude operator, the quantum analog of the conditional probability which has been introduced in [quant-ph/9512022]. The spectrum of the conditional operator characterizing a quantum bipartite system is invariant ... More
The clusters Abell~222 and Abell~223: a multi-wavelength viewMay 18 2010(Abstract abridged) The Abell 222 and 223 clusters are located at an average redshift z ~ 0.21 and are separated by 0.26 deg. Signatures of mergers have been previously found in these clusters, both in X-rays and at opticalwavelengths, thus motivating ... More
The build-up of the Coma cluster by infalling substructuresJul 22 2005We present a new multiwavelength analysis of the Coma cluster subclustering based on recent X-ray data and on a compilation of nearly 900 redshifts. We characterize subclustering using the Serna&Gerbal (1996) hierarchical method which makes use of galaxy ... More
The Intra-cluster Medium Influence on Spiral GalaxiesMar 31 1999We made a detailed analysis of the sample of 39 cluster spiral galaxies of various types observed at H$\alpha$ wavelength by Amram et al. (1992 to 1996), with a scanning Fabry-Perot. We plotted the outer gradient of their rotation curves as a function ... More
The Fundamental Plane of clusters of galaxiesSep 25 1997We have used the ESO Nearby Abell Cluster Survey (ENACS) in combination with the Cosmos Galaxy Catalogue, to investigate the existence of a Fundamental Plane (FP) for rich clusters of galaxies. The 20 clusters with the most regular projected galaxy distributions ... More
The ESO Nearby Abell Cluster Survey. XI. Segregation of cluster galaxies and subclusteringJan 31 2002We study luminosity and morphology segregation of over 3000 cluster galaxies in an ensemble cluster of 59 rich, nearby galaxy clusters observed in the ESO Nearby Cluster Survey (ENACS). Within this sample we identify those galaxies that are in substructures. ... More
Variational properties and orbital stability of standing waves for NLS equation on a star graphJun 22 2012Aug 08 2014We study standing waves for a nonlinear Schr\"odinger equation on a star graph {$\mathcal{G}$} i.e. $N$ half-lines joined at a vertex. At the vertex an interaction occurs described by a boundary condition of delta type with strength $\alpha\leqslant 0$. ... More
ENACSVII, Galaxy density profiles of rich clusters of galaxiesApr 17 1998We have analyzed the projected galaxy distributions in a subset of the ENACS/ COSMOS cluster sample. We made Maximum-Likelihood fits to the distribution of COSMOS galaxies for 4 theoretical profiles, with `cores' (generalized King- and Hubble-profiles) ... More
Evolution of differentiated expression patterns in digital organismsFeb 29 2000We investigate the evolutionary processes behind the development and optimization of multiple threads of execution in digital organisms using the avida platform, a software package that implements Darwinian evolution on populations of self-replicating ... More
On Modelling LifeMay 16 1994We present a theoretical as well as experimental investigation of a population of self-replicating segments of code subject to random mutation and survival of the fittest. Under the assumption that such a system constitutes a minimal system with characteristics ... More
Information theory in molecular biologyMay 05 2004This article introduces the physics of information in the context of molecular biology and genomics. Entropy and information, the two central concepts of Shannon's theory of information and communication, are often confused with each other but play transparent ... More
The use of information theory in evolutionary biologyDec 16 2011Information is a key concept in evolutionary biology. Information is stored in biological organism's genomes, and used to generate the organism as well as to maintain and control it. Information is also "that which evolves". When a population adapts to ... More
Information-theoretic considerations concerning the origin of lifeSep 02 2014Nov 22 2014Research investigating the origins of life usually focuses on exploring possible life-bearing chemistries in the pre-biotic Earth, or else on synthetic approaches. Little work has been done exploring fundamental issues concerning the spontaneous emergence ... More
Toward a fully relativistic theory of quantum informationDec 08 2011Information theory is a statistical theory dealing with the relative state of detectors and physical systems. Because of this physicality of information, the classical framework of Shannon needs to be extended to deal with quantum detectors, perhaps moving ... More
Learning and Complexity in Genetic Auto-Adaptive SystemsJan 27 1994We describe and investigate the learning capablities displayed by a population of self-replicating segments of computer-code subject to random mutation: the tierra environment. We find that learning is achieved through phase transitions that adapt the ... More
Neither weak nor strong entropic Leggett-Garg inequalities can be violatedAug 08 2019Aug 09 2019The Leggett-Garg inequalities probe the classical-quantum boundary by putting limits on the sum of pairwise correlation functions between classical measurement devices that consecutively measured the same quantum system. The apparent violation of these ... More
Ground states for NLS on graphs: a subtle interplay of metric and topologyOct 03 2015We review some recent results on the minimization of the energy associated to the nonlinear Schr\"odinger Equation on non-compact graphs. Starting from seminal results given by the author together with C. Cacciapuoti, D. Finco, and D. Noja for the star ... More
On the Asymptotic Dynamics of a Quantum System Composed by Heavy and Light ParticlesDec 08 2005We consider a non relativistic quantum system consisting of $K$ heavy and $N$ light particles in dimension three, where each heavy particle interacts with the light ones via a two-body potential $\alpha V$. No interaction is assumed among particles of ... More
Deep probing of the Coma clusterFeb 27 1998As a continuation of our study of the faint galaxy luminosity function in the Coma cluster of galaxies, we report here on the first spectroscopic observations of very faint galaxies (R $\le$ 21.5) in the direction of the core of this cluster. Out of these ... More
What is Information?Jan 22 2016Information is a precise concept that can be defined mathematically, but its relationship to what we call "knowledge" is not always made clear. Furthermore, the concepts "entropy" and "information", while deeply related, are distinct and must be used ... More
The Physics of InformationMay 03 2004Information theory is a statistical theory concerned with the relative state of detectors and physical systems. As a consequence, the classical framework of Shannon needs to be extended to deal with quantum detectors, possibly moving at relativistic speeds, ... More
The mind as a computational systemDec 01 2017The present document is an excerpt of an essay that I wrote as part of my application material to graduate school in Computer Science (with a focus on Artificial Intelligence), in 1986. I was not invited by any of the schools that received it, so I became ... More
The complex case of MACSJ0717.5+3745 and its extended filament: intra-cluster light, galaxy luminosity function, and galaxy orientationsMay 26 2019The properties of galaxies are known to be affected by their environment, but although galaxies in clusters and groups have been quite thoroughly investigated, little is known presently on galaxies belonging to filaments of the cosmic web, and on the ... More
Dynamical and content evolution of a sample of clusters from z~0 to z~0.5Sep 05 2000In this paper, we present an analysis of the dynamics and segregation of galaxies in rich clusters from z~0.32 to z~0.48 taken from the CFHT Optical PDCS (COP) survey and from the CNOC survey (Carlberg et al. 1997). Our results from the COP survey are ... More
Simulations Applied to the Bright SHARC XCLF: Results and ImplicationsOct 06 1999We have performed simulations of the effectiveness of the Serendipitous High-redshift Archival ROSAT Cluster (SHARC) survey for various model universes. We find, in agreement with work based on a preliminary set of simulations no statistically significant ... More
A Deep Probing of the Coma clusterAug 22 1997We present here results from a deep spectroscopic survey of the Coma cluster of galaxies (29 galaxies between 18.98<m_R<21.5). Only 1 of these galaxies is within Coma compared to an expected 6.7 galaxies computed from nearby control fields. This discrepancy ... More
The galaxy luminosity function of the Abell 496 cluster and its spatial variationsNov 30 2007We investigate the LF in the very relaxed cluster Abell 496. Our analysis is based on deep images obtained at CFHT with MegaPrime/MegaCam in four bands (ugri) covering a 1x1 deg2 region, which is centered on the cluster Abell 496 and extends to near its ... More
Predator confusion is sufficient to evolve swarming behaviorSep 14 2012Apr 03 2013Swarming behaviors in animals have been extensively studied due to their implications for the evolution of cooperation, social cognition, and predator-prey dynamics. An important goal of these studies is discerning which evolutionary pressures favor the ... More
The Vimos VLT Deep Survey: Compact structures in the CDFSJul 29 2005We have used the Vimos VLT Deep Survey in combination with other spectroscopic, photometric and X-ray surveys from literature to detect several galaxy structures in the Chandra Deep Field South (CDFS). Both a friend-of-friend based algorithm applied to ... More
Coma cluster object populations down to M_R~-9.5Jul 04 2007This study follows a recent analysis of the galaxy luminosity functions and colour-magnitude red sequences in the Coma cluster (Adami et al. 2007). We analyze here the distribution of very faint galaxies and globular clusters in an east-west strip of ... More
Exploring the evolution of a trade-off between vigilance and foraging in group-living organismsAug 08 2014Despite the fact that grouping behavior has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly ... More
Exploring the coevolution of predator and prey morphology and behaviorFeb 29 2016A common idiom in biology education states, "Eyes in the front, the animal hunts. Eyes on the side, the animal hides." In this paper, we explore one possible explanation for why predators tend to have forward-facing, high-acuity visual systems. We do ... More
An optical view of the filament region of Abell 85Jun 26 2008We compare the distribution of optically and Halpha (Ha) selected galaxies in the Southern half of the nearby Abell 85 (A85) cluster with the recently discovered X-ray filament (XRF). We search for galaxies where star formation (SF) may have been triggered ... More
The ESO Nearby Abell Cluster Survey: Properties of the GalaxiesOct 30 1998In this paper we summarize the main properties of the ENACS (the ESO Nearby Abell Cluster Survey), which was one of the ESO Keyprogrammes carried out in the first half of the 1990's, and we discuss some recent work on the properties of the galaxies in ... More
Comparison of two optical cluster finding algorithms for the new generation of deep galaxy surveysOct 03 2003We present a comparison between two optical cluster finding methods: a matched filter algorithm using galaxy angular coordinates and magnitudes, and a percolation algorithm using also redshift information. We test the algorithms on two mock catalogues. ... More
Intracluster light in clusters of galaxies at redshifts 0.4<z<0.8Sep 19 2011The study of intracluster light can help us to understand the mechanisms taking place in galaxy clusters, and to place constraints on the cluster formation history and physical properties. However, owing to the intrinsic faintness of ICL emission, most ... More
The CFH Optical PDCS Survey (COP): First resultsJul 26 1999We present the first results of the COP survey about the reality of the PDCS clusters, about their velocity dispersions and dynamic and about the periodicity of the structures along the line of sight.
The ESO Nearby Abell Cluster Survey: Kinematics of Galaxies in ClustersOct 30 1998We summarize several results based on the velocity data-set for cluster galaxies provided by ENACS (the ESO Nearby Abell Cluster Survey). We describe the distribution of velocity dispersions of a complete sample of rich galaxy clusters, and compare it ... More
Implementation of a Direct-Imaging and FX Correlator for the BEST-2 ArrayJan 27 2014A new digital backend has been developed for the BEST-2 array at Radiotelescopi di Medicina, INAF-IRA, Italy which allows concurrent operation of an FX correlator, and a direct-imaging correlator and beamformer. This backend serves as a platform for testing ... More
Rotation of a melting ice at the surface of a poolOct 22 2015Large circular ice blocks up to 80 m of diameter have been observed on frozen river around the world. This rare event has been reported in a publication in 1993. This fascinating self-fashioned object slowly rotates at about 1$^o$ per second. In this ... More
Diffuse light and building history of the galaxy cluster Abell 2667May 15 2006We have searched for diffuse intracluster light in the galaxy cluster Abell 2667 (z=0.233) from HST images in three filters. We have applied to these images an iterative multi-scale wavelet analysis and reconstruction technique, which allows to subtract ... More
An extension of the SHARC surveyJul 05 2007We report on our search for distant clusters of galaxies based on optical and X-ray follow up observations of X-ray candidates from the SHARC survey. Based on the assumption that the absence of bright optical or radio counterparts to possibly extended ... More
Spatial variations of the optical galaxy luminosity functions and red sequences in the Coma cluster: clues to its assembly historySep 14 2006Oct 06 2006Clusters of galaxies are believed to be at the intersections of cosmological filaments and to grow by accreting matter from these filaments. Such continuous infall has major consequences not only on clusters but also on the physics of cluster galaxies. ... More
Galaxy clusters in the CFHTLS. First matched filter candidate catalogue of the Deep fieldsSep 29 2006We apply a matched-filter cluster detection algorithm to the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) i-band data for the Deep-1, Deep-2, Deep-3 and Deep-4 fields covering a total of 4square degrees. To test the implemented procedure we carry ... More
A Turn-over in the Galaxy Luminosity Function of the Coma Cluster Core?Oct 12 1999Dec 09 1999Our previous study of the faint end (R$\leq$21.5) of the galaxy luminosity function (GLF) was based on spectroscopic data in a small region near the Coma cluster center. In this previous study Adami et al. (1998) suggested, with moderate statistical significance, ... More
Photometric redshifts as a tool to study the Coma cluster galaxy populationsSep 11 2008We investigate the Coma cluster galaxy luminosity function (GLF) at faint magnitudes, in particular in the u* band by applying photometric redshift techniques applied to deep u*, B, V, R, I images covering a region of ~1deg2 (R 24). Global and local GLFs ... More
The VIMOS VLT Deep Survey. The different assembly history of passive and star-forming L_B >= L*_B galaxies in the group environment at z < 1Mar 05 2013Sep 04 2013We use the VIMOS VLT Deep Survey to study the close environment of galaxies in groups at 0.2 <= z < 0.95. Close neighbours of L_B >= L*_B galaxies (Me_B = M_B + 1.1z <= -20) are identified with Me_B <= -18.25 and within a relative distance 5h^-1 kpc <= ... More
Orientations of very faint galaxies in the Coma clusterOct 02 2008We have then searched for preferential orientations of faint galaxies in the Coma cluster (down I_Vega~-11.5). By applying a deconvolution method to deep u* and I band images of the Coma cluster, we were able to recover orientations down to faint magnitudes. ... More
The CFH Optical PDCS survey (COP) I: The DataMar 09 2000This paper presents and gives the COP (COP: CFHT Optical PDCS; CFHT: Canada-France-Hawaii Telescope; PDCS: Palomar Distant Cluster Survey) survey data. We describe our photometric and spectroscopic observations with the MOS multi-slit spectrograph at ... More
On the nature of faint Low Surface Brightness galaxies in the Coma clusterNov 27 2008This project is the continuation of our study of faint Low Surface Brightness Galaxies (fLSBs) in one of the densest nearby galaxy regions known, the Coma cluster. Our goal is to improve our understanding of the nature of these objects by comparing the ... More
The Bright SHARC Survey: The Selection Function and its Impact on the Cluster X-ray Luminosity FunctionJul 19 2000We present the results of a set of simulations designed to quantify the selection function of the Bright SHARC survey for distant clusters. The statistical significance of the simulations relied on the creation of thousands of artificial clusters with ... More
From Entropy to Information: Biased Typewriters and the Origin of LifeJun 23 2015The origin of life can be understood mathematically to be the origin of information that can replicate. The likelihood that entropy spontaneously becomes information can be calculated from first principles, and depends exponentially on the amount of information ... More
Punishment in Public Goods games leads to meta-stable phase transitions and hysteresisOct 18 2012Jun 09 2015The evolution of cooperation has been a perennial problem in evolutionary biology because cooperation can be undermined by selfish cheaters who gain an advantage in the short run, while compromising the long-term viability of the population. Evolutionary ... More
A Simple Explanation for Taxon Abundance PatternsFeb 01 2000For taxonomic levels higher than species, the abundance distributions of number of subtaxa per taxon tend to approximate power laws, but often show strong deviationns from such a law. Previously, these deviations were attributed to finite-time effects ... More
Propagation of Information in Populations of Self-Replicating CodeMay 14 1996We observe the propagation of information in a system of self-replicating strings of code (``Artificial Life'') as a function of fitness and mutation rate. Comparison with theoretical predictions based on the reaction-diffusion equation shows that the ... More
Predicting evolution and visualizing high-dimensional fitness landscapesFeb 12 2013Feb 26 2013The tempo and mode of an adaptive process is strongly determined by the structure of the fitness landscape that underlies it. In order to be able to predict evolutionary outcomes (even on the short term), we must know more about the nature of realistic ... More
Evolution of sustained foraging in 3D environments with physicsDec 21 2011Artificially evolving foraging behavior in simulated legged animals has proved to be a notoriously difficult task. Here, we co-evolve the morphology and controller for virtual organisms in a three-dimensional physically realistic environment to produce ... More
Evolution of genetic organization in digital organismsMar 06 1999We examine the evolution of expression patterns and the organization of genetic information in populations of self-replicating digital organisms. Seeding the experiments with a linearly expressed ancestor, we witness the development of complex, parallel ... More
Stability and symmetry-breaking bifurcation for the ground states of a NLS with a $δ^\prime$ interactionDec 06 2011We determine and study the ground states of a focusing Schr\"odinger equation in dimension one with a power nonlinearity $|\psi|^{2\mu} \psi$ and a strong inhomogeneity represented by a singular point perturbation, the so-called (attractive) $\delta^\prime$ ... More
Evolutionary instability of Zero Determinant strategies demonstrates that winning isn't everythingAug 13 2012Jun 25 2013Zero Determinant (ZD) strategies are a new class of probabilistic and conditional strategies that are able to unilaterally set the expected payoff of an opponent in iterated plays of the Prisoner's Dilemma irrespective of the opponent's strategy, or else ... More
Discovery and information-theoretic characterization of transcription factor binding sites that act cooperativelyJun 05 2015Transcription factor binding to the surface of DNA regulatory regions is one of the primary causes of regulating gene expression levels. A probabilistic approach to model protein-DNA interactions at the sequence level is through Position Weight Matrices ... More