title: The Number of Lattice Rules of Specified Upper Class and Rank

authors: Lyness, J.N.

subjects: mathematics

abstract: The upper class of a lattice rule is a convenient entity for classification and other purposes. The rank of a lattice rule is a basic characteristic, also used for classification. By introducing a rank proportionality factor and obtaining certain recurrence relations, we show how many lattice rules of each rank exist in any prime upper class. The Sylow p-decomposition may be used to obtain corresponding results for any upper class.

text: The Number of Lattice Rules of Specified Upper Class and Rank The upper class of a lattice rule is a convenient entity for classification and other purposes. The rank of a lattice rule is a basic characteristic, also used for classification. By introducing a rank proportionality factor and obtaining certain recurrence relations, we show how many lattice rules of each rank exist in any prime upper class. The Sylow p-decomposition may be used to obtain corresponding results for any upper class.

year: 2003

title: Microbial biogeography of 1,000 geothermal springs: spatial, temporal, and allopatric dynamics of extremophiles in the Taupō Volcanic Zone, Aotearoa-New Zealand

authors: Power, Jean Florence

subjects: Microbiology

abstract: Geothermal springs are model ecosystems to investigate microbial biogeography as they represent discrete, relatively homogeneous habitats, are distributed across multiple geographical scales, and span broad geochemical gradients. This thesis reports the largest consolidated study of geothermal ecosystems to determine causal factors that influence both spatial and temporal biogeographical patterns of extremophiles. Bacterial and archaeal community composition, 46 physicochemical parameters, and metadata from 925 geothermal spring water columns across the Taupō Volcanic Zone (TVZ), Aotearoa-New Zealand were measured. Standardised methodologies were employed to define microbial diversity via 16S rRNA gene amplicon sequencing, and associated physicochemistry, ensuring confidence in sample comparison. Over an 8,000 km² spatial scale, multivariate statistical analyses determined diversity was primarily influenced by pH at temperatures <70 °C; with temperature only having a significant effect at >70 °C. Further, community dissimilarity increased with increasing geographic distance across the region, highlighting niche selection driving assembly at a local scale.

This research also describes the first comprehensive temporal study of geothermal microbial communities in Aotearoa-New Zealand. One hundred and fifteen water column samples from 31 geothermal features were taken over a 34-month period to ascertain microbial community stability, community response to both natural and anthropogenic disturbances in the local environment, and temporal variation in spring diversity across the pH range found in the TVZ. Results indicated temperature and associated groundwater physicochemistry were the most likely parameters to vary stochastically in these geothermal features, with community abundances rather than composition more readily affected by a changing environment. However, variation in pH (pH ±1) had a more significant effect on community structure than temperature (±20 °C), with alpha diversity failing to be an adequate measure of temporal microbial disparity in geothermal features outside of circumneutral conditions. While a substantial physicochemical disturbance was required to shift community structures at the phylum level, geothermal ecosystems were resilient at this broad taxonomic rank and returned to a pre-disturbed state if environmental conditions re-established.

The discovery that genus 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 (phylum Aquificota) exhibited the greatest average abundance (11.2 %) and distribution (74.2 %) of all taxa across 925 geothermal ecosystems in the TVZ, and an apparent absence of this taxon in global geothermal systems, led to the hypothesis that allopatric speciation enabled the evolution of an endemic bacterial genus to Aotearoa-New Zealand. Maximal read abundance of 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 occurred in geothermal features with pH 4-6, 50-70 °C, and low oxidation-reduction potentials, highlighting a specific environmental niche that could enhance habitat isolation. Genomic analysis of the only characterised species for the genus, 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 𝑠𝑡𝑎𝑔𝑛𝑖𝑠𝑝𝑢𝑚𝑎𝑛𝑡𝑖𝑠 CP.B2ᵀ, confirmed a chemolithoautotrophic metabolism dependent on hydrogen oxidation. While similarity between 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 populations illustrated dispersal was not limited across the TVZ, extensive amplicon, metagenomic, and phylogenomic analyses of local and global microbial communities from DNA sequence databases indicated 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 is geographically restricted to the Aotearoa-New Zealand archipelago. It was concluded that combined geographical and physicochemical constraints prevent this taxon from distributing on a broader scale, resulting in the establishment of an endemic bacterial genus.

Collectively, the findings from this thesis provide an insight into ecological behaviour in geothermal springs, highlighting the diverse controls between different taxa within the same habitat-type, and expand understanding of microbial biogeography in extreme ecosystems.

text: Microbial biogeography of 1,000 geothermal springs: spatial, temporal, and allopatric dynamics of extremophiles in the Taupō Volcanic Zone, Aotearoa-New Zealand Geothermal springs are model ecosystems to investigate microbial biogeography as they represent discrete, relatively homogeneous habitats, are distributed across multiple geographical scales, and span broad geochemical gradients. This thesis reports the largest consolidated study of geothermal ecosystems to determine causal factors that influence both spatial and temporal biogeographical patterns of extremophiles. Bacterial and archaeal community composition, 46 physicochemical parameters, and metadata from 925 geothermal spring water columns across the Taupō Volcanic Zone (TVZ), Aotearoa-New Zealand were measured. Standardised methodologies were employed to define microbial diversity via 16S rRNA gene amplicon sequencing, and associated physicochemistry, ensuring confidence in sample comparison. Over an 8,000 km² spatial scale, multivariate statistical analyses determined diversity was primarily influenced by pH at temperatures <70 °C; with temperature only having a significant effect at >70 °C. Further, community dissimilarity increased with increasing geographic distance across the region, highlighting niche selection driving assembly at a local scale.

This research also describes the first comprehensive temporal study of geothermal microbial communities in Aotearoa-New Zealand. One hundred and fifteen water column samples from 31 geothermal features were taken over a 34-month period to ascertain microbial community stability, community response to both natural and anthropogenic disturbances in the local environment, and temporal variation in spring diversity across the pH range found in the TVZ. Results indicated temperature and associated groundwater physicochemistry were the most likely parameters to vary stochastically in these geothermal features, with community abundances rather than composition more readily affected by a changing environment. However, variation in pH (pH ±1) had a more significant effect on community structure than temperature (±20 °C), with alpha diversity failing to be an adequate measure of temporal microbial disparity in geothermal features outside of circumneutral conditions. While a substantial physicochemical disturbance was required to shift community structures at the phylum level, geothermal ecosystems were resilient at this broad taxonomic rank and returned to a pre-disturbed state if environmental conditions re-established.

The discovery that genus 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 (phylum Aquificota) exhibited the greatest average abundance (11.2 %) and distribution (74.2 %) of all taxa across 925 geothermal ecosystems in the TVZ, and an apparent absence of this taxon in global geothermal systems, led to the hypothesis that allopatric speciation enabled the evolution of an endemic bacterial genus to Aotearoa-New Zealand. Maximal read abundance of 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 occurred in geothermal features with pH 4-6, 50-70 °C, and low oxidation-reduction potentials, highlighting a specific environmental niche that could enhance habitat isolation. Genomic analysis of the only characterised species for the genus, 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 𝑠𝑡𝑎𝑔𝑛𝑖𝑠𝑝𝑢𝑚𝑎𝑛𝑡𝑖𝑠 CP.B2ᵀ, confirmed a chemolithoautotrophic metabolism dependent on hydrogen oxidation. While similarity between 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 populations illustrated dispersal was not limited across the TVZ, extensive amplicon, metagenomic, and phylogenomic analyses of local and global microbial communities from DNA sequence databases indicated 𝑉𝑒𝑛𝑒𝑛𝑖𝑣𝑖𝑏𝑟𝑖𝑜 is geographically restricted to the Aotearoa-New Zealand archipelago. It was concluded that combined geographical and physicochemical constraints prevent this taxon from distributing on a broader scale, resulting in the establishment of an endemic bacterial genus.

Collectively, the findings from this thesis provide an insight into ecological behaviour in geothermal springs, highlighting the diverse controls between different taxa within the same habitat-type, and expand understanding of microbial biogeography in extreme ecosystems.

year: 2023

title: Distributed agent-centric system for indigenous data sovereignty

authors: Noovao, Setephano

subjects: holochain

abstract: The sovereignty of indigenous data is a key issue facing indigenous communities. Holochain, a distributed ledger technology, has the potential to address some of the challenges indigenous communities face with respect to data sovereignty. The purpose of this thesis is to critically evaluate the feasibility of using holochain technology to support indigenous data sovereignty. This paper first explores the literature on holochain technology, examining its underlying architecture and features. The research employs a three-phase design science research methodology, conducting an experiment to explore the integration of a decentralized application, holochain, with a prominent cloud service provider. The first phase concentrates on emulating real data-sharing platforms that may utilize data at its disposal, following the principles of indigenous data sovereignty, where a centralized platform could be hosted on a cloud computing service with multiple services in operation. The second phase involves developing a holochain application guided by the principles of indigenous data sovereignty. The final phase seeks to combine the established centralized platform from the first phase with the outcomes of the holochain application from the second phase to experimentally assess whether both technologies can create a data sovereignty solution that aligns with the needs of indigenous data sovereignty. The results of the experiment will provide a solid foundation for understanding the current state of the field and identifying areas where holochain can potentially offer solutions. Furthermore, the results of our research indicate that holochain shows significant promise in tackling the issue of indigenous data sovereignty, although there are considerable limitations that must be addressed and resolved to achieve improved results.

text: Distributed agent-centric system for indigenous data sovereignty The sovereignty of indigenous data is a key issue facing indigenous communities. Holochain, a distributed ledger technology, has the potential to address some of the challenges indigenous communities face with respect to data sovereignty. The purpose of this thesis is to critically evaluate the feasibility of using holochain technology to support indigenous data sovereignty. This paper first explores the literature on holochain technology, examining its underlying architecture and features. The research employs a three-phase design science research methodology, conducting an experiment to explore the integration of a decentralized application, holochain, with a prominent cloud service provider. The first phase concentrates on emulating real data-sharing platforms that may utilize data at its disposal, following the principles of indigenous data sovereignty, where a centralized platform could be hosted on a cloud computing service with multiple services in operation. The second phase involves developing a holochain application guided by the principles of indigenous data sovereignty. The final phase seeks to combine the established centralized platform from the first phase with the outcomes of the holochain application from the second phase to experimentally assess whether both technologies can create a data sovereignty solution that aligns with the needs of indigenous data sovereignty. The results of the experiment will provide a solid foundation for understanding the current state of the field and identifying areas where holochain can potentially offer solutions. Furthermore, the results of our research indicate that holochain shows significant promise in tackling the issue of indigenous data sovereignty, although there are considerable limitations that must be addressed and resolved to achieve improved results.

year: 2024