Exploring Behavior Discovery Methods for Heterogeneous Swarms of Limited-Capability Robots

We study the problem of determining the emergent behaviors that are possible given a functionally heterogeneous swarm of robots with limited capabilities. Prior work has considered behavior search for homogeneous swarms and proposed the use of novelty search over either a hand-specified or learned behavior space followed by clustering to return a taxonomy of emergent behaviors to the user. In this paper, we seek to better understand the role of novelty search and the efficacy of using clustering to discover novel emergent behaviors. Through a large set of experiments and ablations, we analyze the effect of representations, evolutionary search, and various clustering methods in the search for novel behaviors in a heterogeneous swarm. Our results indicate that prior methods fail to discover many interesting behaviors and that an iterative human-in-the-loop discovery process discovers more behaviors than random search, swarm chemistry, and automated behavior discovery. The combined discoveries of our experiments uncover 23 emergent behaviors, 18 of which are novel discoveries. To the best of our knowledge, these are the first known emergent behaviors for heterogeneous swarms of computation-free agents. Videos, code, and appendix are available at the project website: https://sites.google.com/view/heterogeneous-bd-methodsComment: 11 pages, 9 figures, To be published in Proceedings IEEE International Symposium on Multi-Robot & Multi-Agent Systems (MRS 2023

Diffusive behavior for randomly kicked Newtonian particles in a spatially periodic medium

We prove a central limit theorem for the momentum distribution of a particle undergoing an unbiased spatially periodic random forcing at exponentially distributed times without friction. The start is a linear Boltzmann equation for the phase space density, where the average energy of the particle grows linearly in time. Rescaling time, the momentum converges to a Brownian motion, and the position is its time-integral showing superdiffusive scaling with time $t^{3/2}$. The analysis has two parts: (1) to show that the particle spends most of its time at high energy, where the spatial environment is practically invisible; (2) to treat the low energy incursions where the motion is dominated by the deterministic force, with potential drift but where symmetry arguments cancel the ballistic behavior.Comment: 55 pages. Some typos corrected from previous versio

Quantum Computation of Hydrogen Bond Dynamics and Vibrational Spectra

Calculating the observable properties of chemical systems is often classically intractable, and is widely viewed as a promising application of quantum information processing. This is because a full description of chemical behavior relies upon the complex interplay of quantum-mechanical electrons and nuclei, demanding an exponential scaling of computational resources with system size. While considerable progress has been made in mapping electronic-structure calculations to quantum hardware, these approaches are unsuitable for describing the quantum dynamics of nuclei, proton- and hydrogen-transfer processes, or the vibrational spectra of molecules. Here, we use the QSCOUT ion-trap quantum computer to determine the quantum dynamics and vibrational properties of a shared proton within a short-strong hydrogen-bonded system. For a range of initial states, we experimentally drive the ion-trap system to emulate the quantum trajectory of the shared proton wavepacket as it evolves along the potential surface generated by the nuclear frameworks and electronic structure. We then extract the characteristic vibrational frequencies for the shared proton motion to spectroscopic accuracy and determine all energy eigenvalues of the system Hamiltonian to > 99.9% fidelity. Our approach offers a new paradigm for studying the quantum chemical dynamics and vibrational spectra of molecules, and when combined with quantum algorithms for electronic structure, opens the possibility to describe the complete behavior of molecules using exclusively quantum computation techniques.Comment: 10 pages, 4 figure

The institutional shaping of management: in the tracks of English individualism

Globalisation raises important questions about the shaping of economic action by cultural factors. This article explores the formation of what is seen by some as a prime influence on the formation of British management: individualism. Drawing on a range of historical sources, it argues for a comparative approach. In this case, the primary comparison drawn is between England and Scotland. The contention is that there is a systemic approach to authority in Scotland that can be contrasted to a personal approach in England. An examination of the careers of a number of Scottish pioneers of management suggests the roots of this systemic approach in practices of church governance. Ultimately this systemic approach was to take a secondary role to the personal approach engendered by institutions like the universities of Oxford and Cambridge, but it found more success in the different institutional context of the USA. The complexities of dealing with historical evidence are stressed, as is the value of taking a comparative approach. In this case this indicates a need to take religious practice as seriously as religious belief as a source of transferable practice. The article suggests that management should not be seen as a simple response to economic imperatives, but as shaped by the social and cultural context from which it emerges

rs67047829 genotypes of ERV3-1/ZNF117 are associated with lower body mass index in the Polish population

There is now substantial evidence that zinc-finger proteins are implicated in adiposity. Aims were to datamine for high-frequency (near-neutral selection) pretermination-codon (PTC) single-nucleotide polymorphisms (SNPs; n = 141) from a database with > 550,000 variants and analyze possible association with body mass index in a large Polish sample (n = 5757). BMI was regressed (males/females together or separately) against genetic models. Regression for rs67047829 uncovered an interaction-independent association with BMI with both sexes together: mean ± standard deviation, kg/m2: [G];[G], 25.4 ± 4.59 (n = 3650); [G](;)[A], 25.0 ± 4.28 (n = 731); [A];[A], 23.4 ± 3.60 (n = 44); additive model adjusted for age and sex: p = 4.08 × 10–5; beta: − 0.0458, 95% confidence interval (CI) − 0.0732 : − 0.0183; surviving Bonferroni correction; for males: [G];[G], 24.8 ± 4.94 (n = 1878); [G](;)[A], 24.2 ± 4.31 (n = 386); [A];[A], 22.4 ± 3.69 (n = 23); p = 4.20 × 10–4; beta: − 0.0573, CI − 0.0947 : − 0.0199. For average-height males the difference between [G];[G] and [A];[A] genotypes would correspond to ~ 6 kg, suggesting considerable protection against increased BMI. rs67047829 gives a pretermination codon in ERV3-1 which shares an exonic region and possibly promoter with ZNF117, previously associated with adiposity and type-2 diabetes. As this result occurs in a near-neutral Mendelian setting, a drug targetting ERV3-1/ZNF117 might potentially provide considerable benefits with minimal side-effects. This result needs to be replicated, followed by analyses of splice-variant mRNAs and protein expression.The POPULOUS database was the outcome of the project TESTOPLEK which was funded by the Innovative Economy Operational Programme provided by the European Regional Development Fund 2007–2013. This source had no involvement in the study other than funding for the database

Homozygous microdeletion of exon 5 in ZNF277 in a girl with specific language impairment

Peer reviewedPublisher PD

Experimental validation of computerised models of clustering of platelet glycoprotein receptors that signal via tandem SH2 domain proteins

The clustering of platelet glycoprotein receptors with cytosolic YxxL and YxxM motifs, including GPVI, CLEC-2 and PEAR1, triggers activation via phosphorylation of the conserved tyrosine residues and recruitment of the tandem SH2 (Src homology 2) domain effector proteins, Syk and PI 3-kinase. We have modelled the clustering of these receptors with monovalent, divalent and tetravalent soluble ligands and with transmembrane ligands based on the law of mass action using ordinary differential equations and agent-based modelling. The models were experimentally evaluated in platelets and transfected cell lines using monovalent and multivalent ligands, including novel nanobody-based divalent and tetravalent ligands, by fluorescence correlation spectroscopy. Ligand valency, receptor number, receptor dimerisation, receptor phosphorylation and a cytosolic tandem SH2 domain protein act in synergy to drive receptor clustering. Threshold concentrations of a CLEC-2-blocking antibody and Syk inhibitor act in synergy to block platelet aggregation. This offers a strategy for countering the effect of avidity of multivalent ligands and in limiting off-target effects

Dynamical System Modeling of Immune Reconstitution after Allogeneic Stem Cell Transplantation Identifies Patients at Risk for Adverse Outcomes

AbstractSystems that evolve over time and follow mathematical laws as they evolve are called dynamical systems. Lymphocyte recovery and clinical outcomes in 41 allograft recipients conditioned using antithymocyte globulin (ATG) and 4.5-Gy total body irradiation were studied to determine if immune reconstitution could be described as a dynamical system. Survival, relapse, and graft-versus-host disease (GVHD) were not significantly different in 2 cohorts of patients receiving different doses of ATG. However, donor-derived CD3+ cell reconstitution was superior in the lower ATG dose cohort, and there were fewer instances of donor lymphocyte infusion (DLI). Lymphoid recovery was plotted in each individual over time and demonstrated 1 of 3 sigmoid growth patterns: Pattern A (n = 15) had rapid growth with high lymphocyte counts, pattern B (n = 14) had slower growth with intermediate recovery, and pattern C (n = 10) had poor lymphocyte reconstitution. There was a significant association between lymphocyte recovery patterns and both the rate of change of donor-derived CD3+ at day 30 after stem cell transplantation (SCT) and clinical outcomes. GVHD was observed more frequently with pattern A, relapse and DLI more so with pattern C, with a consequent survival advantage in patients with patterns A and B. We conclude that evaluating immune reconstitution after SCT as a dynamical system may differentiate patients at risk of adverse outcomes and allow early intervention to modulate that risk

EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Westerlund 1 and 2 Open Clusters Survey

Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions among stars. Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars. The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun. Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically, the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec. Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation were carried out using the ACIS-Extract software. Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a photon flux threshold of approximately 2 × 10−8 photons cm−2 s −1 . The X-ray sources exhibit a highly concentrated spatial distribution, with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.Fil: Guarcello, Mario Giuseppe. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Flaccomio, Ettore. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Albacete Colombo, Juan Facundo. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Almendros Abad, Víctor. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Anastasopoulou, Konstantina. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Andersen, M.. European Southern Observatory; AlemaniaFil: Argiroffi, C.. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; Italia. Università degli Studi di Palermo; ItaliaFil: Bayo, Amelia. European Southern Observatory; AlemaniaFil: Bartlett, E.S.. European Southern Observatory; AlemaniaFil: Bastian, N.. Donostia International Physics Center; España. Basque Foundation For Science; España. Liverpool John Moores University; Reino UnidoFil: De Becker, Michaël. Université de Liège; BélgicaFil: Best, William M. J.. University of Texas at Austin; Estados UnidosFil: Bonito, R.. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Borghese, Alice. Instituto de Astrofísica de Canarias; España. Universidad de La Laguna; EspañaFil: Calzetti, D.. University of Massachusetts; Estados UnidosFil: Castellanos, R.. Centro de Astrobiología; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Cecchi Pestellini, C.. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Clark, J. S.. The Open University; Reino UnidoFil: Clarke, C. J.. University of Cambridge; Estados UnidosFil: Zelati, Francesco Coti. Instituto de Estudios Espaciales de Cataluña; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Damiani, Jeremy. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Drake, J.J.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Gennaro, Mario. Space Telescope Science Institute; Estados Unidos. University Johns Hopkins; Estados UnidosFil: Mapelli, M.. Università di Padova; Italia. Ruprecht Karls Universitat Heidelberg; AlemaniaFil: Martinez Galarza, J. R.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Micela, G.. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; ItaliaFil: Miceli, M.. Istituto Nazionale di Astrofísica. Osservatorio Astronómico di Palermo; Italia. Università degli Studi di Palermo; ItaliaFil: Moraux, E.. Universite Grenoble Alpes; FranciaFil: Winter, A.. Observatoire de la Côte D'azur; Francia. Universite Grenoble Alpes; FranciaFil: Wright, N. J.. Keele University; Reino UnidoFil: Zeidler, Peter. European Southern Observatory; Alemania. Space Telescope Science Institute; Estados Unido