Two Notes on APCol Systems

In this work, we continue our research in the eld of string processing mem- brane systems - APCol systems. We focus on a relation of APCol systems with PM colonies - colonies whose agents can only perform point mutation transformations of the common string, in a vicinity of the agent. The second part is devoted to a connection of APCol systems and logic circuits using AND, OR and NOT gates

Automaton-like P Colonies

In this paper we study P colonies where the environment is given as a string. These variants, called automaton-like P systems or APCol systems, behave like automata: during functioning, the agents change their own states and process the symbols of the string. We develop the concept of APCol systems by introducing the notion of their generating working mode. We then compare the power of APCol systems working in the generating mode and that of register machines and context-free matrix grammars with and without appearance checking

Towards P Colonies Processing Strings

In this paper we introduce and study P colonies where the environment is given as a string. These variants of P colonies, called Automaton-like P systems or APCol systems, behave like automata: during functioning, the agents change their own states and process the symbols of the string. After introducing the concept of APCol systems, we examine their computational power. It is shown that the family of languages accepted by jumping nite automata is properly included in the family of languages accepted by APCol systems with one agent, and it is proved that any recursively enumerable language can be obtained as a projection of a language accepted by an Automaton-like P colony with two agents

Inner-suburban neighbourhoods, activist research and the social space of the commercial street

This paper tracks the transition of “creative city” planning from the gentrified downtown to the disinvested inner-suburbs. It attends particularly to contradictory notions of community mobilized by proponents of inner-suburban revitalization and by residents and business owners who daily inhabit inner-suburban commercial streets where cultural planning interventions are typically targeted. It further argues that those contradictory notions indicate immanent displacement pressure. The argument builds around data gleaned from an action research project in Toronto’s Mount Dennis neighbourhood, a former manufacturing neighbourhood that is now home to a large number of precariously employed new immigrants. We contend that community engaged research not only allows for an analysis of the race and class dimensions of creative city planning, it consolidates marginalized perspectives and opens up alternative possibilities for planning and development. We also claim that the relational, exploratory and sometimes fraught process of sharing knowledge with community-based researchers enriches critical research on the exclusionary politics of redevelopment planning

Inner-suburban neighbourhoods, activist research and the social space of the commercial street

This paper tracks the transition of “creative city” planning from the gentrified downtown to the disinvested inner-suburbs. It attends particularly to contradictory notions of community mobilized by proponents of inner-suburban revitalization and by residents and business owners who daily inhabit inner-suburban commercial streets where cultural planning interventions are typically targeted. It further argues that those contradictory notions indicate immanent displacement pressure. The argument builds around data gleaned from an action research project in Toronto’s Mount Dennis neighbourhood, a former manufacturing neighbourhood that is now home to a large number of precariously employed new immigrants. We contend that community engaged research not only allows for an analysis of the race and class dimensions of creative city planning, it consolidates marginalized perspectives and opens up alternative possibilities for planning and development. We also claim that the relational, exploratory and sometimes fraught process of sharing knowledge with community-based researchers enriches critical research on the exclusionary politics of redevelopment planning

Active Stars in the Spectroscopic Survey of Mid-to-Late M Dwarfs Within 15pc

We present results from the volume-complete spectroscopic survey of 0.1-0.3M$_\odot$ M dwarfs within 15pc. This work discusses the active sample without close binary companions, providing a comprehensive picture of these 123 stars with H${\alpha}$ emission stronger than -1\unicode{xC5}. Our analysis includes rotation periods (including 31 new measurements), H${\alpha}$ equivalent widths, rotational broadening, inclinations, and radial velocities, determined using high-resolution, multi-epoch spectroscopic data from the TRES and CHIRON spectrographs supplemented by photometry from TESS and MEarth. Using this volume-complete sample, we establish that the majority of active, low-mass M dwarfs are very rapid rotators: specifically, 74$\pm$4% have rotation periods shorter than 2 days, while 19$\pm$4% have intermediate rotation periods of 2-20 days, and the remaining 8$\pm$3% have periods longer than 20 days. Among the latter group, we identify a population of stars with very high H${\alpha}$ emission, which we suggest is indicative of dramatic spindown as these stars transition from the rapidly to slowly rotating modes. We are unable to determine rotation periods for six stars and suggest that some of the stars without measured rotation periods may be viewed pole-on, as such stars are absent from the distribution of inclinations we measure; this lack notwithstanding, we recover the expected isotropic distribution of spin axes. Our spectroscopic and photometric data sets also allow us to investigate activity-induced radial-velocity variability, which we show can be estimated as the product of rotational broadening and the photometric amplitude of spot modulation.Comment: Accepted for publication in AJ; 18 pages, 12 figures, 3 table

On the Nature of Ultra-faint Dwarf Galaxy Candidates. II. The Case of Cetus II

We obtained deep Gemini GMOS-S g, r photometry of the ultra-faint dwarf galaxy candidate Cetus II with the aim of providing stronger constraints on its size, luminosity, and stellar population. Cetus II is an important object in the size-luminosity plane, as it occupies the transition zone between dwarf galaxies and star clusters. All known objects smaller than Cetus II (r h ∼ 20 pc) are reported to be star clusters, while most larger objects are likely dwarf galaxies. We found a prominent excess of main-sequence stars in the color-magnitude diagram of Cetus II, best described by a single stellar population with an age of 11.2 Gyr, metallicity of [Fe/H] = -1.28 dex, an [α/Fe] = 0.0 dex at a heliocentric distance of 26.3 ±1.2 kpc. As well as being spatially located within the Sagittarius dwarf tidal stream, these properties are well matched to the Sagittarius galaxy's Population B stars. Interestingly, like our recent findings on the ultra-faint dwarf galaxy candidate Tucana V, the stellar field in the direction of Cetus II shows no evidence of a concentrated overdensity despite tracing the main sequence for over six magnitudes. These results strongly support the picture that Cetus II is not an ultra-faint stellar system in the Milky Way halo, but made up of stars from the Sagittarius tidal stream.B.C.C. and H.J. acknowledge the support of the Australian Research Council through Discovery project DP150100862