Complex dynamics of elementary cellular automata emerging from chaotic rules

We show techniques of analyzing complex dynamics of cellular automata (CA) with chaotic behaviour. CA are well known computational substrates for studying emergent collective behaviour, complexity, randomness and interaction between order and chaotic systems. A number of attempts have been made to classify CA functions on their space-time dynamics and to predict behaviour of any given function. Examples include mechanical computation, \lambda{} and Z-parameters, mean field theory, differential equations and number conserving features. We aim to classify CA based on their behaviour when they act in a historical mode, i.e. as CA with memory. We demonstrate that cell-state transition rules enriched with memory quickly transform a chaotic system converging to a complex global behaviour from almost any initial condition. Thus just in few steps we can select chaotic rules without exhaustive computational experiments or recurring to additional parameters. We provide analysis of well-known chaotic functions in one-dimensional CA, and decompose dynamics of the automata using majority memory exploring glider dynamics and reactions

Cellular automaton supercolliders

Gliders in one-dimensional cellular automata are compact groups of non-quiescent and non-ether patterns (ether represents a periodic background) translating along automaton lattice. They are cellular-automaton analogous of localizations or quasi-local collective excitations travelling in a spatially extended non-linear medium. They can be considered as binary strings or symbols travelling along a one-dimensional ring, interacting with each other and changing their states, or symbolic values, as a result of interactions. We analyse what types of interaction occur between gliders travelling on a cellular automaton `cyclotron' and build a catalog of the most common reactions. We demonstrate that collisions between gliders emulate the basic types of interaction that occur between localizations in non-linear media: fusion, elastic collision, and soliton-like collision. Computational outcomes of a swarm of gliders circling on a one-dimensional torus are analysed via implementation of cyclic tag systems

Housing bubbles and land planning corruption: evidence from Spain’s largest municipalities

Purpose: The purpose of this paper is to quantify to what extent the housing bubble in the early-to-mid 2000s in Spain exacerbated land planning corruption among Spain’s largest municipalities. Design/methodology/approach: The authors exploit plausibly exogenous variation in housing prices induced by changes in local mortgage market conditions; namely, the rapid expansion of savings banks (Cajas de Ahorros). Accounting for electoral competition in the 2003–2007 and 2007–2009 electoral cycles among Spanish municipalities larger than 25, 000 inhabitants, the authors estimate a positive relationship between housing prices and land planning corruption in municipalities with variation in savings bank establishments using instrumental variables techniques. Findings: A 1% increase in housing prices leads to a 3.9% points increase in the probability of land planning corruption. Moreover, absolute majority governments (not needing other parties’ support) are more susceptible to the incidence of corruption than non-majority ones. Two policy implications to address corruption emerge: enhance electoral competition and increase scrutiny over land planning decisions in sparsely populated. Originality/value: First empirical evidence of a formal link between the 2000s housing bubble in Spain and land planning corruption

CMB anisotropy: deviations from Gaussianity due to non-linear gravity

Non-linear evolution of cosmological energy density fluctuations triggers deviations from Gaussianity in the temperature distribution of the cosmic microwave background. A method to estimate these deviations is proposed. N-body simulations -- in a $\Lambda$CDM cosmology -- are used to simulate the strongly non-linear evolution of cosmological structures. It is proved that these simulations can be combined with the potential approximation to calculate the statistical moments of the CMB anisotropies produced by non-linear gravity. Some of these moments are computed and the resulting values are different from those corresponding to Gaussianity.Comment: 6 latex pages with mn.sty, 3 eps figures. Accepted in MNRA

Distribution of melanopsin positive neurons in pigmented and albino mice: evidence for melanopsin interneurons in the mouse retina.

Here we have studied the population of intrinsically photosensitive retinal ganglion cells (ipRGCs) in adult pigmented and albino mice. Our data show that although pigmented (C57Bl/6) and albino (Swiss) mice have a similar total number of ipRGCs, their distribution is slightly different: while in pigmented mice ipRGCs are more abundant in the temporal retina, in albinos the ipRGCs are more abundant in superior retina. In both strains, ipRGCs are located in the retinal periphery, in the areas of lower Brn3a(+)RGC density. Both strains also contain displaced ipRGCs (d-ipRGCs) in the inner nuclear layer (INL) that account for 14% of total ipRGCs in pigmented mice and 5% in albinos. Tracing from both superior colliculli shows that 98% (pigmented) and 97% (albino) of the total ipRGCs, become retrogradely labeled, while double immunodetection of melanopsin and Brn3a confirms that few ipRGCs express this transcription factor in mice. Rather surprisingly, application of a retrograde tracer to the optic nerve (ON) labels all ipRGCs, except for a sub-population of the d-ipRGCs (14% in pigmented and 28% in albino, respectively) and melanopsin positive cells residing in the ciliary marginal zone (CMZ) of the retina. In the CMZ, between 20% (pigmented) and 24% (albino) of the melanopsin positive cells are unlabeled by the tracer and we suggest that this may be because they fail to send an axon into the ON. As such, this study provides the first evidence for a population of melanopsin interneurons in the mammalian retina

Methanol to gasoline (MTG): Parametric study and validation of the process in a two-zone fluidized bed reactor (TZFBR)

Methanol to Gasoline (MTG) process transforms methanol to hydrocarbons within the boiling point range of gasoline. The result is a wide spectrum of products (olefins, paraffins, aromatics and naphthenics, among others), with the total conversion of methanol to hydrocarbons and water. Catalyst deactivation by coke is a main problem in this process. This work aims to determine the feasibility of carrying out the production of gasoline from methanol in a two-zone fluidized bed reactor (TZFBR). The hypothesis is that the formation of carbonaceous deposits (coke) on the catalyst particles can be counteracted by its combustion in the regeneration zone that this novel reactor presents, thus achieving stable and continuous operation. In this way, both processes (reaction and regeneration) would be being carried out simultaneously in the same reactor (process intensification). The comparison of results between a conventional fluidized bed reactor and a TZFBR shows that the second one actually provides a better stability over time

Pure hydrogen from biogas: Intensified methane dry reforming in a two-zone fluidized bed reactor using permselective membranes

Methane dry reforming of biogas can be a sustainable source of hydrogen but the development of this technology is hindered by limitations such as endothermicity and catalyst deactivation by coke. A two zone fluidized bed reactor coupling permselective Pd/Ag membranes counteracts them and allows to intensify the process obtaining a stable pure hydrogen production. Here we report the effect of operation variables (i.e., temperature, total bed height, nature and partial pressure of regenerative agent, relative height of the regeneration and reaction zones, and use of an activation period) on the yield to hydrogen and stability of the process. Hydrogen over-yields, compared with the conventional fluidized bed reactor, in the range of +200% to +100% were obtained for the entire interval of temperatures 475–575 °C whilst maintaining stable operation by continuous catalyst regeneration. Around 70% of it was pure hydrogen coming from the permeate side of the membranes. The proposed reactor configuration greatly increases both methane conversion and selectivity to hydrogen (expressed as H 2 /CO ratio), not only in relation to our own conventional reactor findings but also regarding other published results

Methanol to Gasoline (MTG): preparation, characterization and testing of HZSM-5 zeolite-based catalysts to be used in a fluidized bed reactor

The preparation of catalysts suitable for MTG processes in a fluidized bed reactor has been studied with emphasis on improving the textural, physico-chemical, morphological, structural and mechanical properties. A mixture of HZSM-5 zeolite (active material), boehmite or bentonite (binder) and alumina (inert filler) was used to prepare different catalysts. After preparation, characterization by physical adsorption of N2, XRF, XRD and SEM-EDX techniques was carried out. The screening of catalysts was performed in a fluidized bed reactor. The distribution of products was very similar in all cases, with the yield of light hydrocarbons always being higher than that of gasoline. Among the catalysts tested, the one containing boehmite as a binder (HZ_Boeh) was found as the most appropriate due to its high mechanical strength, high yield to aromatics and lower yield to durene