Tuwhera Research Repository

The Tuwhera Research Repository provides sustainable open access and archiving to a broad range of AUT produced research - theses, research outputs and datasets.

Theses & dissertations

Deposit your thesis

Datasets

Deposit your dataset

Research outputs

Deposit your research output
via Research Elements

Recent Submissions

Access status: Open Access ,
Soil Type and Temperature Determine Soil Respiration Seasonal Dynamics in Dairy Grassland
(Springer Science and Business Media LLC, 2024-06-06) Liu, Y; Zhang, J; Bader, MKF; Leuzinger, S
Soil respiration rates (Rₛ) were measured in New Zealand dairy grassland. Both season and soil type significantly affected Rₛ. Soil temperature and soil type dominated overall Rₛ. Soil respiration (Rₛ), the CO₂ release from root respiration and microbial metabolism, affects global soil carbon storage and cycling. Only few studies have looked at Rₛ in the southern hemisphere, especially regarding the interaction between soil type and environmental factors on Rₛ in dairy grassland. We investigated the relationship between Rₛ and soil temperature (Tₛ), soil water content (SWC), soil type, and other environmental factors based on summer and winter measurements at four sites in New Zealand. Across sites, soil respiration rates ranged from 0.29 to 14.58 with a mean of 5.38 ± 0.13 (mean ± standard error) µmol CO₂ m⁻² s⁻¹. Mean summer Rₛ was 86.5% higher than mean winter Rs, largely driven by organic/gley and pumice soils while ultic soils showed very little seasonal temperature sensitivity. Overall mean Rₛ in organic/gley soils was 108.0% higher than that in ultic soils. The high Rₛ rate observed in organic/gley was likely due to high soil organic matter content, while low Rs in ultic and pallic soils resulted from high clay content and low hydraulic conductance. Soil temperature drove overall Rₛ. Our findings indicate that soil type and soil temperature together best explain Rₛ. This implies that a mere classification of land use type may be insufficient for global C models and should be supplemented with soil type information, at least locally. (Figure presented.)
Access status: Open Access ,
Design and Analysis of Large-Scale Tests of a Self-Centring Seismic-Resilient Steel MRF
(Springer Nature Switzerland, 2025-07-31) Elettore, Elena; Roumieh, Ali; Freddi, Fabio; Latour, Massimo; Francavilla, Antonella B; Di Benedetto, Sabatino; Gutiérrez-Urzúa, Fernando; Pieroni, Ludovica; Simpson, Barbara; Barbosa, Andrea R; Ramhormozian, Shahab; Grant, Damian N; Rizzano, Gianvittorio; Ribeiro, Filipe L; Correia, Antonio A; O'Reilly, GJ; Calvi, GM
Conventional seismic design methods rely on structural inelastic hysteretic response to dissipate seismic energy. This approach often results in extensive damage and substantial direct and indirect losses following high-intensity earthquakes, thereby affecting the overall resilience of communities. To address this issue, modern earthquake engineering is facing an extraordinarily challenging era in providing affordable, high-seismic-performance structures able to minimise both seismic damage and repair time. To this end, the ERIES SC-RESTEEL (Self-Centring seismic-RESilient sTEEL structures) project examines the structural response, repairability, resilience, and performance recovery of low-damage self-centring steel Moment-Resisting Frames (MRFs) equipped with friction devices and post-tensioned bars with disc springs at column bases and beam-to-column joints. Shaking table tests will be conducted at LNEC (Laboratório Nacional de Engenharia Civil) in Lisbon, Portugal, to investigate the performance of a large-scale 3-storey steel MRF. Key objectives include evaluating the seismic performance of the structure, its reparability strategy, and the performance after repairs. This paper presents the test specimen design, advanced Finite Element analyses of various joint configurations, and the preparatory work for the tests. The findings offer valuable insights into the expected experimental outcomes.
Access status: Open Access ,
Dynamic Pricing Optimization for Load Aggregators in Virtual Power Plants Considering User Clustering and Response Behavior
(Elsevier BV, 2026-07-31) Yang, X; Zhao, M; Gao, W; Zhou, Shuai; Han, J; Ge, Z; Liu, Y
Load aggregators (LAs) can integrate end users with adjustable loads within a specific region and participate in electricity spot markets to mitigate the growing peak–valley imbalance in power demand. As an important enabler of demand-side flexibility and user participation, LAs play a critical role in enhancing the operational efficiency of new-type power systems. This study proposes a two-stage dynamic pricing framework for LAs within virtual power plant (VPP) environments. In the first stage, a K-means++ clustering algorithm is applied to classify end users according to their load characteristics and demand response capabilities. In the second stage, a Stackelberg game is formulated to characterize the hierarchical interaction between the LA (leader) and end users (followers), taking into account operational constraints and market uncertainties. Four simulation scenarios are designed to validate the proposed model. The results show that the optimized pricing strategy reduces electricity costs by 3.57% for non-residential users and 2.45% for residential users, while improving load smoothness and LA profitability. The proposed framework provides a practical and scalable approach for optimizing LA pricing strategies and offers valuable insights for enhancing user participation and renewable energy integration in real-time electricity markets.
Access status: Open Access ,
Effect of Increasing Cognitive Activity Participation via Calligraphy Practice on Salient Network and Central Executive Network in Older Adults With Subjective Cognitive Decline: A Secondary Analysis of a Randomized Controlled Trial
(Frontiers Media SA, 2026-07-24) Li, Jing; Luo, Yishan; Huo, Zhaohua; Shi, Lin; Chu, Winnie Chiu Wing; Lam, Linda Chiu Wa; Lee, Allen Ting Chun
Objectives: Regular participation in late-life cognitive activities is associated with a reduced risk of dementia. In a prior randomized controlled trial, we demonstrated that increased calligraphy practice improved working memory and strengthened functional connectivity (FC) within the default mode network in older adults with subjective cognitive decline (SCD). This exploratory secondary analysis examined whether increased calligraphy practice also modulates FC in other large-scale brain networks.Methods: A total of 112 community-dwelling Chinese adults aged 55–75 years with SCD and prior calligraphy experience were randomly assigned to a control or intervention group. The control group maintained their usual calligraphy practice, while the intervention group doubled their weekly practice time for 6 months. Resting-state FC was assessed at baseline and post-intervention using functional magnetic resonance imaging (fMRI). Mixed models for repeated measures were conducted to compare longitudinal FC changes within the salient network and central executive network between groups.Results: Compared with the control group, doubling calligraphy practice for 6 months was associated with a significantly greater increase in resting-state FC between right rostral prefrontal cortex and right supramarginal gyrus within the salient network (between-group mean difference = 0.12; 95% CI = 0.03–0.22; p = 0.01). In pooled analyses of the whole sample, no significant pre-post changes in FCs within SAN were observed. No significant between-group FC changes were observed within the central executive network.Conclusion: Increased calligraphy practice was associated with localized FC changes within the salient network, extending our prior findings of more distributed FC changes within the default mode network. Together, these findings suggest late-life engagement in cognitive activities may be relevant to large-scale brain network organization in older adults at risk of dementia.
Access status: Open Access ,
Pragmatic, Brief, Free, and Validated: Screening, Assessment and Outcome Measures for Gambling Treatment
(Elsevier BV, 2025-10-10) Dowling, Nicki; Rodda, Simone
Private and public gambling treatment services are available worldwide, yet there is limited guidance on selecting screening, assessment, and treatment outcome measures for practical use. The most effective treatments are cognitive behavioral therapies (CBT) and motivational interviewing (MI), often adapted to incorporate cultural and holistic approaches. Although multiple systematic reviews have proposed sets of measures, few are designed specifically for service delivery in community settings. This paper outlines pragmatic selection criteria for measures in these settings, recommending that they be validated, brief, free to use, and suitable for self-administration by gambling clients or their family members and friends (affected others). After reviewing existing guidelines and recommendations, the article provides an overview of measures appropriate for routine use and discusses delivery considerations such as timing, administration mode, and client engagement. It emphasizes the importance of aligning measurement tools with treatment goals and adapting them for culturally diverse contexts. While outcome measurement for gambling clients is relatively well developed, process and outcome measures for affected others remain limited.