title: Phylogeogrpahy and genetic diversity of terrestrial arthropods from the Ross Dependency, Antarctica

authors: Demetras, Nicholas J.

subjects: mtDNA

abstract: The pattern of genetic diversity in many species observed today can be traced back to historic ecological events that influenced the distribution of species not only on a global but also a local scale. For example, historical events such as habitat fragmentation, divergence in isolation, and subsequent range expansion, can result in a recognisable pattern of genetic variation which can be used to infer ecological factors (e.g. effective population size, dispersal capacity), as well as those affecting speciation processes. This thesis examines these issues from a phylogeographic and phylogenetic perspective by analysing patterns of variation in the mtDNA cytochrome c oxidase sub-unit 1 (COI) gene in two co-occurring Antarctic endemic arthropods in Southern Victoria Land, Ross Dependency.
Within the Southern Victoria Land Dry Valleys of Garwood, Marshall and Miers, populations of the springtail Gomphiocephalus hodgsoni (Collembola: Hypogastruridae) and mite Stereotydeus mollis (Acari: Prostigmata) revealed consistently dissimilar patterns of genetic structure. COI divergence within G. hodgsoni was less than 0.7%, while divergence within S. mollis reached upwards of 17%. Within our study area G. hodgsoni and S. mollis harboured 10 and 22 haplotypes, respectively and showed links to previously sampled populations across Southern Victoria Land. The distribution of G. hodgsoni haplotypes across sites was homogenous while those of S. mollis were distinctly heterogenous. The extremely low genetic variation and links to previously sampled populations suggest that G. hodgsoni is a relatively recent colonist within our study area and/or the victim of an extreme bottleneck event. On the other hand, the extreme levels of genetic diversity observed for S. mollis, and the occurrence of two highly divergent haplotypes that were unique to our study area, suggest that: (1) S. mollis may have had a longer association in isolation with our southern study area; and/or (2) S. mollis has colonised our study area on more than one occasion via multiple extant refugial populations.
Throughout its entire Southern Victoria Land range S. mollis is characterised by extremely high levels of mtDNA (COI) divergence (greater than 17%), suggesting a possible multi species complex. To examine this issue, I used both Neighbour Joining (NJ) and Maximum Likelihood (ML) methods to construct a phylogeny utilising all 50 known unique S. mollis sequences with other Victoria Land congeners including an available S. belli sequence, and several new S. shoupi sequences. Both NJ and ML analyses revealed significantly congruent trees with strong bootstrap support. The morphologically similar S. shoupi was placed as a monophyletic sister group, basal to S. mollis in both analyses with strong support. However, there was disagreement between the two methods in the placement of the single S. belli sequence within in the resulting phylogenies which was not possible to resolve with the current data. Despite this latter uncertainty, the possibility of cryptic species within S. mollis remains.
Collectively, these studies have demonstrated differences in the genetic structure between two co-occurring species and suggested how similar historic processes, combined with differing life history attributes can lead to that differentiation. Furthermore, genetic analyses were used to identify isolated and unique populations, which are likely to be of high conservation value.

text: Phylogeogrpahy and genetic diversity of terrestrial arthropods from the Ross Dependency, Antarctica The pattern of genetic diversity in many species observed today can be traced back to historic ecological events that influenced the distribution of species not only on a global but also a local scale. For example, historical events such as habitat fragmentation, divergence in isolation, and subsequent range expansion, can result in a recognisable pattern of genetic variation which can be used to infer ecological factors (e.g. effective population size, dispersal capacity), as well as those affecting speciation processes. This thesis examines these issues from a phylogeographic and phylogenetic perspective by analysing patterns of variation in the mtDNA cytochrome c oxidase sub-unit 1 (COI) gene in two co-occurring Antarctic endemic arthropods in Southern Victoria Land, Ross Dependency.
Within the Southern Victoria Land Dry Valleys of Garwood, Marshall and Miers, populations of the springtail Gomphiocephalus hodgsoni (Collembola: Hypogastruridae) and mite Stereotydeus mollis (Acari: Prostigmata) revealed consistently dissimilar patterns of genetic structure. COI divergence within G. hodgsoni was less than 0.7%, while divergence within S. mollis reached upwards of 17%. Within our study area G. hodgsoni and S. mollis harboured 10 and 22 haplotypes, respectively and showed links to previously sampled populations across Southern Victoria Land. The distribution of G. hodgsoni haplotypes across sites was homogenous while those of S. mollis were distinctly heterogenous. The extremely low genetic variation and links to previously sampled populations suggest that G. hodgsoni is a relatively recent colonist within our study area and/or the victim of an extreme bottleneck event. On the other hand, the extreme levels of genetic diversity observed for S. mollis, and the occurrence of two highly divergent haplotypes that were unique to our study area, suggest that: (1) S. mollis may have had a longer association in isolation with our southern study area; and/or (2) S. mollis has colonised our study area on more than one occasion via multiple extant refugial populations.
Throughout its entire Southern Victoria Land range S. mollis is characterised by extremely high levels of mtDNA (COI) divergence (greater than 17%), suggesting a possible multi species complex. To examine this issue, I used both Neighbour Joining (NJ) and Maximum Likelihood (ML) methods to construct a phylogeny utilising all 50 known unique S. mollis sequences with other Victoria Land congeners including an available S. belli sequence, and several new S. shoupi sequences. Both NJ and ML analyses revealed significantly congruent trees with strong bootstrap support. The morphologically similar S. shoupi was placed as a monophyletic sister group, basal to S. mollis in both analyses with strong support. However, there was disagreement between the two methods in the placement of the single S. belli sequence within in the resulting phylogenies which was not possible to resolve with the current data. Despite this latter uncertainty, the possibility of cryptic species within S. mollis remains.
Collectively, these studies have demonstrated differences in the genetic structure between two co-occurring species and suggested how similar historic processes, combined with differing life history attributes can lead to that differentiation. Furthermore, genetic analyses were used to identify isolated and unique populations, which are likely to be of high conservation value.

year: 2010

title: Jitter measurement in digital signals by using software defined radio technology

authors: Anthonys, Gehan

abstract: Here, we propose a method using software defined radio (SDR) technology to measure periodic and random jitter in a digital signal. Conventional methods to measure jitter required expensive measurement equipment. We use a cheap (less than US $40) SDR USB dongle to expose random and periodic jitter in the amplitude modulated light source of a range camera. By using Fourier analysis we generate an ideal reference signal to enable to extract jitter at the zero crossings of the signal under test. We measure jitter with SDR receiver and more conventionally a real-time digital oscilloscope. From the SDR receiver, we find the periodic jitter at low frequency and compare to the oscilloscope results. We demonstrate that periodic and random jitter can be detected on a RF signal with consumer priced products provided that the jitter frequency less within the bandwidth of the receiver.

text: Jitter measurement in digital signals by using software defined radio technology Here, we propose a method using software defined radio (SDR) technology to measure periodic and random jitter in a digital signal. Conventional methods to measure jitter required expensive measurement equipment. We use a cheap (less than US $40) SDR USB dongle to expose random and periodic jitter in the amplitude modulated light source of a range camera. By using Fourier analysis we generate an ideal reference signal to enable to extract jitter at the zero crossings of the signal under test. We measure jitter with SDR receiver and more conventionally a real-time digital oscilloscope. From the SDR receiver, we find the periodic jitter at low frequency and compare to the oscilloscope results. We demonstrate that periodic and random jitter can be detected on a RF signal with consumer priced products provided that the jitter frequency less within the bandwidth of the receiver.

year: 2019

title: Cultural justice, ethics and teaching

authors: Nairn, Ray

subjects: Maori

abstract: Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

text: Cultural justice, ethics and teaching Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

year: 1993