title: Islands in the sand: are all hypolithic microbial communities the same?

authors: Lebre, Pedro H.

subjects: hypolithon

abstract: Hypolithic microbial communities (hypolithons) are complex assemblages of phototrophic and heterotrophic organisms associated with the ventral surfaces of translucent minerals embedded in soil surfaces. Past studies on the assembly, structure and function of hypolithic communities have tended to use composite samples (i.e. bulked hypolithic biomass) with the underlying assumption that samples collected from within a ‘homogeneous’ locality are phylogenetically homogeneous. In this study, we question this assumption by analysing the prokaryote phylogenetic diversity of multiple individual hypolithons: i.e. asking the seemingly simple question of ‘Are all hypolithons the same’? Using 16S rRNA gene-based phylogenetic analysis of hypolithons recovered for a localized moraine region in the Taylor Valley, McMurdo Dry Valleys, Antarctica, we demonstrate that these communities are heterogeneous at very small spatial scales (&amp;lt;5 m). Using null models of phylogenetic turnover, we showed that this heterogeneity between hypolithons is probably due to stochastic effects such as dispersal limitations, which is entirely consistent with the physically isolated nature of the hypolithic communities (‘islands in the sand’) and the almost complete absence of a liquid continuum as a mode of microbial transport between communities.

text: Islands in the sand: are all hypolithic microbial communities the same? Hypolithic microbial communities (hypolithons) are complex assemblages of phototrophic and heterotrophic organisms associated with the ventral surfaces of translucent minerals embedded in soil surfaces. Past studies on the assembly, structure and function of hypolithic communities have tended to use composite samples (i.e. bulked hypolithic biomass) with the underlying assumption that samples collected from within a ‘homogeneous’ locality are phylogenetically homogeneous. In this study, we question this assumption by analysing the prokaryote phylogenetic diversity of multiple individual hypolithons: i.e. asking the seemingly simple question of ‘Are all hypolithons the same’? Using 16S rRNA gene-based phylogenetic analysis of hypolithons recovered for a localized moraine region in the Taylor Valley, McMurdo Dry Valleys, Antarctica, we demonstrate that these communities are heterogeneous at very small spatial scales (&amp;lt;5 m). Using null models of phylogenetic turnover, we showed that this heterogeneity between hypolithons is probably due to stochastic effects such as dispersal limitations, which is entirely consistent with the physically isolated nature of the hypolithic communities (‘islands in the sand’) and the almost complete absence of a liquid continuum as a mode of microbial transport between communities.

year: 2021

title: Modular Supervisor Synthesis for Extended Finite-State Machines Subject to Controllability

authors: Malik, Robi

subjects: Science & Technology

abstract: This paper proposes an algorithm for the synthesis of modular supervisors using extended finite-state machines, i.e., state machines with variables and guards on the transitions. Synthesis is performed by iteratively selecting components from a synchronous composition until a least restrictive controllable solution is obtained. This method is usually faster and produces smaller supervisors than standard monolithic synthesis, while offering the modelling benefits of variables. An example of manufacturing system control illustrates the approach.

text: Modular Supervisor Synthesis for Extended Finite-State Machines Subject to Controllability This paper proposes an algorithm for the synthesis of modular supervisors using extended finite-state machines, i.e., state machines with variables and guards on the transitions. Synthesis is performed by iteratively selecting components from a synchronous composition until a least restrictive controllable solution is obtained. This method is usually faster and produces smaller supervisors than standard monolithic synthesis, while offering the modelling benefits of variables. An example of manufacturing system control illustrates the approach.

year: 2016-01-01

title: Whaikoorero: a study of formal Maori speech

authors: Mahuta, Robert Te Kotahi

subjects: Whaikoorero

abstract: Whaikoorero is regarded as the traditionally valued mode of communication. It is the language of the marae, the language of the chiefs and elders, and the only acceptable form of public statement in the Maori world. At the same time it is an artistic form, difficult to master, and demanding long years of practice and experience.
It is true, as I have pointed out, that one can read and listen to the myths and traditions of the Maori in books, on tapes, and through radio broadcasts. Yet it is the public rendering, the synthesising of myth and tradition, the living and the dead, and the interweaving of topical matters with the beliefs and values of the society, which hold the greatest interest for the Maori. For in whaikoorero history is relived, man reaffirmed, and status gained. The dead are recalled to participate with the living in social gatherings where tradition is orally transmitted, reaffirmed and relived. These then are some of the reasons why whaikoorero persists as a literary form and as a social feature within contemporary Maori society.

text: Whaikoorero: a study of formal Maori speech Whaikoorero is regarded as the traditionally valued mode of communication. It is the language of the marae, the language of the chiefs and elders, and the only acceptable form of public statement in the Maori world. At the same time it is an artistic form, difficult to master, and demanding long years of practice and experience.
It is true, as I have pointed out, that one can read and listen to the myths and traditions of the Maori in books, on tapes, and through radio broadcasts. Yet it is the public rendering, the synthesising of myth and tradition, the living and the dead, and the interweaving of topical matters with the beliefs and values of the society, which hold the greatest interest for the Maori. For in whaikoorero history is relived, man reaffirmed, and status gained. The dead are recalled to participate with the living in social gatherings where tradition is orally transmitted, reaffirmed and relived. These then are some of the reasons why whaikoorero persists as a literary form and as a social feature within contemporary Maori society.

year: 1974