title: Contrasting phylogeographical patterns for springtails reflect different evolutionary histories between the Antarctic Peninsula and continental Antarctica

authors: McGaughran, Angela

subjects: Antarctica

abstract: Aim: We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence.
Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni.
Methods: Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II).
Results: Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma–present) time-scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several 'phylogroups' (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion.
Main conclusions: We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments.

text: Contrasting phylogeographical patterns for springtails reflect different evolutionary histories between the Antarctic Peninsula and continental Antarctica Aim: We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence.
Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni.
Methods: Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II).
Results: Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma–present) time-scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several 'phylogroups' (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion.
Main conclusions: We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments.

year: 2009

title: Modular control-loop detection

authors: Malik, Robi

subjects: computer science

abstract: This paper presents an efficient algorithm to
detect control-loops in large finite-state systems. The proposed
algorithm exploits the modular structure present in many
models of practical relevance, and often successfully avoids the
explicit synchronous composition of subsystems and thereby
the state explosion problem. Experimental results show that
the method can be used to verify industrial applications of
considerable complexity.

text: Modular control-loop detection This paper presents an efficient algorithm to
detect control-loops in large finite-state systems. The proposed
algorithm exploits the modular structure present in many
models of practical relevance, and often successfully avoids the
explicit synchronous composition of subsystems and thereby
the state explosion problem. Experimental results show that
the method can be used to verify industrial applications of
considerable complexity.

year: 2006-07

title: Kava and Maaori: New drug fashion or re-engagement with 'kawa'? [Invited presentation]

authors: Aporosa, S. 'Apo'

abstract: It is estimated there are more than 20,000 kava users in New Zealand on an average Friday or Saturday night, with increasing interest and uptake of this indigenous drink by Māori. This presentation argues that some of that increased use of kava by Māori can be interpreted as a cultural expression of pre-migration Hawaiki, rather than simply a new interaction with a foreign drug substance.

text: Kava and Maaori: New drug fashion or re-engagement with 'kawa'? [Invited presentation] It is estimated there are more than 20,000 kava users in New Zealand on an average Friday or Saturday night, with increasing interest and uptake of this indigenous drink by Māori. This presentation argues that some of that increased use of kava by Māori can be interpreted as a cultural expression of pre-migration Hawaiki, rather than simply a new interaction with a foreign drug substance.

year: 2016