263 research outputs found

    Von Neumann Regular Cellular Automata

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    For any group GG and any set AA, a cellular automaton (CA) is a transformation of the configuration space AGA^G defined via a finite memory set and a local function. Let CA(G;A)\text{CA}(G;A) be the monoid of all CA over AGA^G. In this paper, we investigate a generalisation of the inverse of a CA from the semigroup-theoretic perspective. An element τCA(G;A)\tau \in \text{CA}(G;A) is von Neumann regular (or simply regular) if there exists σCA(G;A)\sigma \in \text{CA}(G;A) such that τστ=τ\tau \circ \sigma \circ \tau = \tau and στσ=σ\sigma \circ \tau \circ \sigma = \sigma, where \circ is the composition of functions. Such an element σ\sigma is called a generalised inverse of τ\tau. The monoid CA(G;A)\text{CA}(G;A) itself is regular if all its elements are regular. We establish that CA(G;A)\text{CA}(G;A) is regular if and only if G=1\vert G \vert = 1 or A=1\vert A \vert = 1, and we characterise all regular elements in CA(G;A)\text{CA}(G;A) when GG and AA are both finite. Furthermore, we study regular linear CA when A=VA= V is a vector space over a field F\mathbb{F}; in particular, we show that every regular linear CA is invertible when GG is torsion-free elementary amenable (e.g. when G=Zd, dNG=\mathbb{Z}^d, \ d \in \mathbb{N}) and V=FV=\mathbb{F}, and that every linear CA is regular when VV is finite-dimensional and GG is locally finite with Char(F)o(g)\text{Char}(\mathbb{F}) \nmid o(g) for all gGg \in G.Comment: 10 pages. Theorem 5 corrected from previous versions, in A. Dennunzio, E. Formenti, L. Manzoni, A.E. Porreca (Eds.): Cellular Automata and Discrete Complex Systems, AUTOMATA 2017, LNCS 10248, pp. 44-55, Springer, 201

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Microsatellites for the genus Cucurbita and an SSR-based genetic linkage map of Cucurbita pepo L.

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    Until recently, only a few microsatellites have been available for Cucurbita, thus their development is highly desirable. The Austrian oil-pumpkin variety Gleisdorfer Ölkürbis (C. pepo subsp. pepo) and the C. moschata cultivar Soler (Puerto Rico) were used for SSR development. SSR-enriched partial genomic libraries were established and 2,400 clones were sequenced. Of these 1,058 (44%) contained an SSR at least four repeats long. Primers were designed for 532 SSRs; 500 primer pairs produced fragments of expected size. Of these, 405 (81%) amplified polymorphic fragments in a set of 12 genotypes: three C. moschata, one C. ecuadorensis, and eight C. pepo representing all eight cultivar groups. On an average, C. pepo and C. moschata produced 3.3 alleles per primer pair, showing high inter-species transferability. There were 187 SSR markers detecting polymorphism between the USA oil-pumpkin variety “Lady Godiva” (O5) and the Italian crookneck variety “Bianco Friulano” (CN), which are the parents of our previous F2 mapping population. It has been used to construct the first published C. pepo map, containing mainly RAPD and AFLP markers. Now the updated map comprises 178 SSRs, 244 AFLPs, 230 RAPDs, five SCARs, and two morphological traits (h and B). It contains 20 linkage groups with a map density of 2.9 cM. The observed genome coverage (Co) is 86.8%

    An examination of the self-referent executive processing model of test anxiety: control, emotional regulation, self-handicapping, and examination performance

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    According to the self-referent executive processing (S-REF) model, test anxiety develops from interactions between three systems: executive self-regulation processes, self-beliefs, and maladaptive situational interactions. Studies have tended to examine one system at a time, often in conjunction with how test anxiety relates to achievement outcomes. The aim of this study was to enable a more thorough test of the S-REF model by examining one key construct from each of these systems simultaneously. These were control (a self-belief construct), emotional regulation through suppression and reappraisal (an executive process), and self-handicapping (a maladaptive situational interaction). Relations were examined from control, emotional regulation, and self-handicapping to cognitive test anxiety (worry), and subsequent examination performance on a high-stakes test. Data were collected from 273 participants in their final year of secondary education. A structural equation model showed that higher control was indirectly related to better examination performance through lower worry, higher reappraisal was indirectly related to worse examination performance through higher worry, and higher self-handicapping was related to worse examination performance through lower control and higher worry. These findings suggest that increasing control and reducing self-handicapping would be key foci for test anxiety interventions to incorporate. © 2018 The Author(s

    Whole-body tissue stabilization and selective extractions via tissue-hydrogel hybrids for high-resolution intact circuit mapping and phenotyping

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    To facilitate fine-scale phenotyping of whole specimens, we describe here a set of tissue fixation-embedding, detergent-clearing and staining protocols that can be used to transform excised organs and whole organisms into optically transparent samples within 1–2 weeks without compromising their cellular architecture or endogenous fluorescence. PACT (passive CLARITY technique) and PARS (perfusion-assisted agent release in situ) use tissue-hydrogel hybrids to stabilize tissue biomolecules during selective lipid extraction, resulting in enhanced clearing efficiency and sample integrity. Furthermore, the macromolecule permeability of PACT- and PARS-processed tissue hybrids supports the diffusion of immunolabels throughout intact tissue, whereas RIMS (refractive index matching solution) grants high-resolution imaging at depth by further reducing light scattering in cleared and uncleared samples alike. These methods are adaptable to difficult-to-image tissues, such as bone (PACT-deCAL), and to magnified single-cell visualization (ePACT). Together, these protocols and solutions enable phenotyping of subcellular components and tracing cellular connectivity in intact biological networks

    Jet reconstruction and performance using particle flow with the ATLAS Detector

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    This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb −1−1 of ATLAS data from 8 TeV proton–proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker. This improves the accuracy of the charged-hadron measurement, while retaining the calorimeter measurements of neutral-particle energies. The paper places emphasis on how this is achieved, while minimising double-counting of charged-hadron signals between the inner tracker and calorimeter. The performance of particle flow jets, formed from the ensemble of signals from the calorimeter and the inner tracker, is compared to that of jets reconstructed from calorimeter energy deposits alone, demonstrating improvements in resolution and pile-up stability

    Search for heavy neutral Higgs bosons produced in association with b-quarks and decaying into b-quarks at root s=13 TeV with the ATLAS detector

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    A search for heavy neutral Higgs bosons produced in association with one or two b -quarks and decaying to b -quark pairs is presented using 27.8  fb − 1 of √ s = 13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015 and 2016. No evidence of a signal is found. Upper limits on the heavy neutral Higgs boson production cross section times its branching ratio to b ¯ b are set, ranging from 4.0 to 0.6 pb at 95% confidence level over a Higgs boson mass range of 450 to 1400 GeV. Results are interpreted within the two-Higgs-doublet model and the minimal supersymmetric Standard Model

    Measurement of the tt¯tt¯ production cross section in pp collisions at √s=13 TeV with the ATLAS detector

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    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17−15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7−6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb

    Measurement of single top-quark production in association with a W boson in the single-lepton channel at \sqrt{s} = 8\,\text {TeV} with the ATLAS detector

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    The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at \sqrt{s} = 8\,\text {TeV}. The dataset corresponds to an integrated luminosity of 20.2\,\text {fb}^{-1}, and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant t{\bar{t}} background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is \sigma _{tW} = 26 \pm 7\,\text {pb}, in good agreement with the Standard Model expectation
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