title: Institutions and uncertainty: An empirical investigation

authors: Ryan, Michael

subjects: thesis with publication

abstract: This thesis presents four papers on the role institutions (defined as Douglass North defined institutions) play in generating uncertainty. Specifically, we focus on how uncertainty changes as institutions change. The thesis is empirically focused. In answering our research questions, we employ, often in combination, tools from the ‘traditional’ econometric literature—in particular, structural vector autoregressions— and tools from the natural language processing literature.
Two of the papers in this thesis focus on New Zealand’s wide-ranging institutional reforms, which took place from the mid-1980s to the mid-1990. Drawing on the purpose Douglass North stated for institutions: ‘to reduce uncertainty in exchange’ (North, 1991a, p. 97), we argue that institutional reform is only successful if it lowers uncertainty. We find evidence that New Zealand’s reform lowered uncertainty in general (at least, from firms’ point of view), as well as uncertainty about tax and transfers. We also argue in this thesis that institutional change might affect not just the level of uncertainty but also its composition (in terms of the types of uncertainty experienced). Motivated by the ‘Mundellian trilemma’, we argue that if every monetary regime/ institutional setup is imperfect in its own way, then the types of
uncertainty associated with the regime will be idiosyncratic. Based on an analysis of a large corpus of historical newspaper articles, using natural language methods, we find the different monetary regimes adopted by the United States and the United Kingdom since 1890 are generally idiosyncratic in terms of the types of uncertainty they generate. In this thesis we also exploit the institutions—uncertainty link for another purpose: the identification of uncertainty shocks. A problem in research on the business cycle impact of uncertainty is finding movements in uncertainty that are plausibly exogenous to the business cycle (‘uncertainty shocks’). We narratively identify (using the New Zealand parliamentary record) a set of quarters where heightened uncertainty was the result of institutional or policy change, rather than the state of the business cycle. We use these quarters as instruments in a proxy structural vector autoregression to quantify the effect of uncertainty on output (amongst other variables). Comparing our results with the conventional recursive method for identifying uncertainty shocks, we find uncertainty shocks have a much larger impact on output. This suggests the estimates from the conventional recursive method suffer from attenuation bias.

text: Institutions and uncertainty: An empirical investigation This thesis presents four papers on the role institutions (defined as Douglass North defined institutions) play in generating uncertainty. Specifically, we focus on how uncertainty changes as institutions change. The thesis is empirically focused. In answering our research questions, we employ, often in combination, tools from the ‘traditional’ econometric literature—in particular, structural vector autoregressions— and tools from the natural language processing literature.
Two of the papers in this thesis focus on New Zealand’s wide-ranging institutional reforms, which took place from the mid-1980s to the mid-1990. Drawing on the purpose Douglass North stated for institutions: ‘to reduce uncertainty in exchange’ (North, 1991a, p. 97), we argue that institutional reform is only successful if it lowers uncertainty. We find evidence that New Zealand’s reform lowered uncertainty in general (at least, from firms’ point of view), as well as uncertainty about tax and transfers. We also argue in this thesis that institutional change might affect not just the level of uncertainty but also its composition (in terms of the types of uncertainty experienced). Motivated by the ‘Mundellian trilemma’, we argue that if every monetary regime/ institutional setup is imperfect in its own way, then the types of
uncertainty associated with the regime will be idiosyncratic. Based on an analysis of a large corpus of historical newspaper articles, using natural language methods, we find the different monetary regimes adopted by the United States and the United Kingdom since 1890 are generally idiosyncratic in terms of the types of uncertainty they generate. In this thesis we also exploit the institutions—uncertainty link for another purpose: the identification of uncertainty shocks. A problem in research on the business cycle impact of uncertainty is finding movements in uncertainty that are plausibly exogenous to the business cycle (‘uncertainty shocks’). We narratively identify (using the New Zealand parliamentary record) a set of quarters where heightened uncertainty was the result of institutional or policy change, rather than the state of the business cycle. We use these quarters as instruments in a proxy structural vector autoregression to quantify the effect of uncertainty on output (amongst other variables). Comparing our results with the conventional recursive method for identifying uncertainty shocks, we find uncertainty shocks have a much larger impact on output. This suggests the estimates from the conventional recursive method suffer from attenuation bias.

year: 2022

title: Ancient Borrelia genomes document the evolutionary history of louse-borne relapsing fever

authors: Swali, Pooja

abstract: Several bacterial pathogens have transitioned from tick-borne to louse-borne transmission, which often involves genome reduction and increasing virulence. However, the timing of such transitions remains unclear. We sequenced four ancient Borrelia recurrentis genomes, the agent of louse-borne relapsing fever, dating from 2300 to 600 years ago. We estimated the divergence from its closest tick-borne relative to 6000 to 4000 years ago, which suggests an emergence coinciding with human lifestyle changes such as the advent of wool-based textiles. Pan-genome analysis indicated that much of the evolution characteristic of B. recurrentis had occurred by ~2300 years ago, though further gene turnover, particularly in plasmid partitioning, persisted until ~1000 years ago. Our findings provide a direct genomic chronology of the evolution of this specialized vector-borne pathogen.

text: Ancient Borrelia genomes document the evolutionary history of louse-borne relapsing fever Several bacterial pathogens have transitioned from tick-borne to louse-borne transmission, which often involves genome reduction and increasing virulence. However, the timing of such transitions remains unclear. We sequenced four ancient Borrelia recurrentis genomes, the agent of louse-borne relapsing fever, dating from 2300 to 600 years ago. We estimated the divergence from its closest tick-borne relative to 6000 to 4000 years ago, which suggests an emergence coinciding with human lifestyle changes such as the advent of wool-based textiles. Pan-genome analysis indicated that much of the evolution characteristic of B. recurrentis had occurred by ~2300 years ago, though further gene turnover, particularly in plasmid partitioning, persisted until ~1000 years ago. Our findings provide a direct genomic chronology of the evolution of this specialized vector-borne pathogen.

year: 2025

title: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

text: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020 Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

year: 2021