Showing papers by "University of Canterbury published in 2022"

First evidence of microplastics in Antarctic snow

Abstract: Abstract. In recent years, airborne microplastics have been identified in a range of remote environments. However, data throughout the Southern Hemisphere, in particular Antarctica, are largely absent to date. We collected snow samples from 19 sites across the Ross Island region of Antarctica. Suspected microplastic particles were isolated and their composition confirmed using micro-Fourier transform infrared spectroscopy (µFTIR). We identified microplastics in all Antarctic snow samples at an average concentration of 29 particles L−1, with fibres the most common morphotype and polyethylene terephthalate (PET) the most common polymer. To investigate sources, backward air mass trajectories were run from the time of sampling. These indicate potential long-range transportation of up to 6000 km, assuming a residence time of 6.5 d. Local sources were also identified as potential inputs into the environment as the polymers identified were consistent with those used in clothing and equipment from nearby research stations. This study adds to the growing body of literature regarding microplastics as a ubiquitous airborne pollutant and establishes their presence in Antarctica.

Stakeholders’ perspectives on BIM and LCA for green buildings

Abstract: There is growing concern about the environmental impacts of buildings on climate change. In this regard, the concept of integrating building technologies and environmental assessment methods, namely Building Information Modelling (BIM) and Life Cycle Assessment (LCA), has arisen as an innovative approach to improve building environmental assessment at the design phase. Recent studies made attempts to develop theoretical frameworks for BIM and LCA integration focusing on the technical aspects and the challenges of this integration. However, the stakeholders' perspectives on this integration of BIM and LCA for building environmental assessment have been overlooked. Therefore, there is a pressing need to understand the stakeholders' perspectives on BIM and LCA and their value for improving green building design and assessment. This study contributes to the existing knowledge on the potential implementation of an integrated BIM-LCA framework for building environmental assessment. To this end, this study investigates (1) the current applications of BIM and LCA in green buildings from the stakeholders' perspectives and (2) the stakeholders' level of awareness and agreement on the significance of BIM and LCA for green building design and assessment. In order to achieve this goal, a national survey was conducted among multiple stakeholders in the New Zealand building industry. The results indicate that BIM and LCA applications for green buildings are still immature. A statistically significant correlation is observed between the importance of BIM and LCA applications for green buildings. The stakeholders perceive BIM and LCA potentials and their integration positively. However, the current practices and applications of BIM and LCA do not align with the stakeholders’ perceptions. Massive efforts are still required for a wide implementation of BIM and LCA and their potential integration for green buildings.

Strain and orientation engineering in ABO₃ perovskite oxide thin films

Abstract: Perovskite oxides with chemical formula ABO3are widely studied for their properties including ferroelectricity, magnetism, strongly correlated physics, optical effects, and superconductivity. A thriving research direction using such materials is through their integration as epitaxial thin films, allowing many novel and exotic effects to be discovered. The integration of the thin film on a single crystal substrate, however, can produce unique and powerful effects, and can even induce phases in the thin film that are not stable in bulk. The substrate imposed mechanical boundary conditions such as strain, crystallographic orientation, octahedral rotation patterns, and symmetry can also affect the functional properties of perovskite films. Here, the author reviews the current state of the art in epitaxial strain and orientation engineering in perovskite oxide thin films. The paper begins by introducing the effect of uniform conventional biaxial strain, and then moves to describe how the substrate crystallographic orientation can induce symmetry changes in the film materials. Various material case studies, including ferroelectrics, magnetically ordered materials, and nonlinear optical oxides are covered. The connectivity of the oxygen octahedra between film and substrate depending on the strain level as well as the crystallographic orientation is then discussed. The review concludes with open questions and suggestions worthy of the community's focus in the future.

Risk science offers an integrated approach to resilience

Abstract: Why do we hear calls to separate and independently manage aspects of risk and resilience that are inherently related? These arguments are inconsistent with more holistic and integrated responses to wicked challenges—such as climate change—that are necessary if we are to find balances and synergies. The justification of such views is based on misconceptions of risk science that are no longer accurate. Rather than being irrelevant, the risk concept and related literature provide a wealth of resilience analysis resources that are potentially being overlooked. In this Perspective, we discuss how the modern view of risk can provide an integrated framework for the key aspects of resilience. In the face of growing calls to restrict risk analysis to narrow and specific events, this Perspectives argues instead for fully integrated frameworks that bring risk analysis into all aspects of resilience studies.

Glacier and rock glacier changes since the 1950s in the La Laguna catchment, Chile

Abstract: Abstract. Glaciers and rock glaciers play an important role in the hydrology of the semi-arid northern Chile. Several studies show that glaciers have rapidly lost mass in response to climate change during the last decades. The response of rock glaciers to climate change in this region is, however, less known. In this study we use a combination of historical aerial photography, stereo satellite imagery, airborne lidar, and the Shuttle Radar Topography Mission (SRTM) DEM to report glacier changes for the Tapado Glacier–rock glacier complex from the 1950s to 2020 and to report mass balances for the glacier component of the complex, Tapado Glacier. Furthermore, we examine high-resolution elevation changes and surface velocities between 2012 and 2020 for 35 rock glaciers in the La Laguna catchment. Our results show how Tapado Glacier has shrunk by -25.2±4.6 % between 1956 and 2020, while the mass balance of Tapado Glacier has become steadily more negative, from being approximately in balance between 1956 and 1978 (-0.04±0.08 m w.e. a−1) to showing increased losses between 2015 and 2020 (-0.32±0.08 m w.e. a−1). Climatological (re-)analyses reveal a general increase in air temperature, decrease in humidity, and variable precipitation since the 1980s in the region. In particular, the severe droughts starting in 2010 resulted in a negative mass balance of -0.54±0.10 m w.e. a−1 between 2012 and 2015. The rock glaciers within the La Laguna catchment show heterogenous changes, with some sections of landforms exhibiting pronounced elevation changes and surface velocities exceeding that of Tapado Glacier. This could be indicative of high ice contents within the landforms and also highlights the importance of considering how landforms can transition from more glacial landforms to more periglacial features under permafrost conditions. As such, we believe high-resolution (sub-metre) elevation changes and surface velocities are a useful first step for identifying ice-rich landforms.

Late Pleistocene-Holocene aeolian loess-paleosol sections in the Yellow River source area on the northeast Tibetan Plateau: chronostratigraphy, sediment provenance, and implications for paleoclimate reconstruction

Abstract: Two late Pleistocene-Holocene aeolian loess-paleosol sections were identified in the Yellow River source area on the northeast (NE) Tibetan Plateau. Based on the comprehensive study on multiple proxies, AMS 14C and optically stimulated luminescence (OSL) dates, these two sections have a basal age of 14000–11500 yr BP, suggesting that they accumulated since the last deglaciation. Four stages of paleoclimate evolution can be summarized as follows. (1) A cold-dry period was dominated by the Westerlies in the late Pleistocene (ca. 14000–11500 yr BP). (2) A gradual transition to warm-wet with the weakened Westerlies and strengthened East Asian summer monsoon (EASM) occurred in the early Holocene (ca. 11500–9000 yr BP). (3) A warm-wet episode was under strong EASM in the middle Holocene (ca. 9000–3100 yr BP), however, a cold event was identified at 5000–3500 yr BP, which was caused by the abrupt weakening of the EASM and the strengthening of the Westerlies. (4) A phase of gradually shifting to dry-cold was controlled by the weakened EASM and strengthened Westerlies (after ca. 3100 yr BP). The assemblage of grain-size end-member modelling analysis (EM1-EM5) and heavy minerals indicated that aeolian deposit units have multiple sediment provenances and transport processes. EM1 is clay deposits composed of secondary clay minerals produced during weathering and pedogenesis, whereas EM2 is fine silts derived from distant dust transported through long-existing high-level Westerlies. EM3 and EM4 are coarse silts that originated from the moraines and periglacial deposits in the middle and distant source areas transported by the Westerlies and Tibetan Plateau Monsoon. Lastly, EM5 is sand from fluvial deposits and slope clastics transported by strong valley wind within the local area. This study is helpful to understand the mechanisms of paleoclimate evolution on the NE Tibetan Plateau. It also has important implications for characterizing and subdividing aeolian loess in China.

Investigating the effect of nudges for improving comment quality in active video watching

Abstract: Developing and maintaining constructive engagement is a crucial challenge in learning by watching videos. AVW-Space is an online video-based learning platform which enhances student engagement via note-taking and personalised support. Previous studies with AVW-Space show that students who write comments, especially high-quality comments, learn more. The goal of the study reported in this paper is to encourage students to write better-quality comments. After automating the assessment of comment quality using machine learning approaches, we developed Quality nudges which encourage students to write better comments. We conducted a study in a first-year engineering course to analyse the learning effects of the Quality nudges. The results show that Quality nudges enhanced constructive engagement and learning. The contribution of this research is in proposing methodology for increasing the quality of student comments in video-based learning.

Disentangling Niche Theory and Beta Diversity Change

Abstract: AbstractBeta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favors habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e., its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

Parenting During a Pandemic: Predictors of Parental Burnout

Abstract: The global pandemic, COVID-19, has resulted in significant changes in many aspects of our lives. For parents, the impact has been great as they combine work, family, and homeschooling while maintaining the wellbeing of themselves and their family. COVID-19 has brought about challenges that many parents have not faced before, putting them at risk for parental burnout. The goal of this study was to investigate risk and protective factors that predict parental burnout during COVID-19. Eighty-six parents (75 mothers; M age = 40.73; SD = 7.88) living in New Zealand during COVID-19 lockdown participated in the survey. Results showed parental violence, parental constellation, unemployment, major decreases in finances, and living in a disadvantaged neighborhood were the strongest predictors of parental burnout. Child independence and parental emotional regulation were the strongest protective predictors of parental burnout. COVID-19 restrictions did not predict parental burnout. Findings highlight that promoting protective factors may support parental equilibrium during future crises.

The influence of audio effects and attention on the perceived duration of interaction

Abstract: • Examines the influence of audio effects on perceived duration of interactive tasks. • Increasing-tempo beeps shortens perceived duration of interactive tasks. • Examines the influence of interface attentional demand on perceived duration. • Perceived duration is reduced with higher interface attentional demand. • Shows the effect of prospective versus retrospective methodology on time perception. Users often need to wait for computer systems to perform some task, and these delays can have adverse effects on user experience. One way to ease the problem is to use stimuli that reduce perceived wait time. We conducted a study investigating how audio effects influence users perceived wait time across three interaction contexts — passive waiting with no visual feedback, passive waiting with visual feedback (watching a progress bar), and playing a simple game. We tested three different types of audio effects: a series of beeps that changed in tempo (increasing, decreasing, or constant tempo), a series of beeps that changed in pitch (rising, falling, or constant), and variants of a polyphonic Shepard tone (an auditory illusion that seems to rise or fall in pitch continuously); a silent condition was included as a baseline. In the first stage of the experiment, participants experienced a 10.1 second wait period, indicated with a progress bar, accompanied by an audio effect. They then estimated the duration of the wait, making a retrospective assessment of the experience. In the second stage, participants experienced a series of conditions that compared two 10.1 second wait periods accompanied by different effects and selected which one (if either) felt longer, making a prospective assessment (i.e., they were aware that the two durations would be compared before experiencing them). Results from the first stage showed that perceived duration differed across different audio conditions. Results from the second stage supported prior findings that increasing-tempo beeps can shorten perceived duration and generalised the findings to interactions that include visual feedback (e.g., watching a progress bar) and those involving direct interaction (e.g., playing a simple game).

Nonlinear Finite-Element Modeling of HF2V Lead Extrusion Damping Devices: Generic Design Tool

Abstract: Supplemental energy-dissipation devices are increasingly used to protect structures, limiting loads transferred to structures and absorbing significant response energy without sacrificial s...

Parker Ice Tongue Collapse, Antarctica, Triggered by Loss of Stabilizing Land‐Fast Sea Ice

Abstract: After a likely multi-century period of intermittent calving, the full length of Parker Ice Tongue (18 km or 41 km2), calved in March 2020 co-incident with repeated summer break-outs of the surrounding land-fast sea ice. A complete ice tongue collapse for these otherwise stable glaciological landmarks along the Victoria Land Coast is previously unrecorded. Prior to break-off, we found an inverse correlation between fast ice extent and ice tongue velocities (R = −0.62; R2 = 0.39). The short summer period, characterized by decreased land-fast sea ice extent, showed around 11% higher velocities compared to winter. Any previous events of comparable magnitude could not have occurred since at least ∼1,850, assuming continuous growth (∼193m yr−1) derived from the last 60 years of satellite observations. We highlight the vulnerability of the ice tongue once left exposed to oceanic processes, which poses questions about the fate of other ice tongues if land-fast sea ice decreases more broadly in the future.

Bio-inspired lattice structure optimisation with strain trajectory aligned trusses

Abstract: Lattice structures have great potential for lightweight additively manufactured parts. This paper presents a bio-inspired functionally graded lattice structure optimisation approach for compliance minimisation of statically loaded structures. Topology optimisation determines the optimal relative density distribution within a design space and the associated strain fields. A lattice structure is then generated within this design space, comprised of trusses aligned with principal strain trajectories. The trusses have a rectangular cross-section, resulting in three size variable per node during the final sizing step. A minimum feature size is implemented so that the designs are suited to the particular additive manufacturing process print resolution. The presented approach is further demonstrated to efficiently solve problems with multiple load cases and produce lattice topologies that mimic those found in bone. The optimised lattice structure examples presented are on average 12% less stiff in comparison to a conventional SIMP topology optimisation approach. However, they are well suited to multifunctional applications such as heat transfer where the surface area is increased by an average of 94%. The optimised lattice structures are also shown to be able to eliminate additive manufacturing support structure requirements.

Psychological capital, social capital and organizational resilience: A Herringbone Model perspective

Abstract: The resilience of small and medium enterprises (SMEs) can emerge from entrepreneurial and organizational factors. Yet, the joint role of psychological capital (PsyCap), social capital (SC), and organizational resilience (OR) in facilitating tourism SMEs recovery remains uncovered. Organizational resilience models are either conceptual and/or mainly derived from studies on large organizations focusing on their strategic and operational capabilities, with the resource and capabilities constraints faced by SMEs largely ignored. This study applies the Herringbone model of organizational resilience to evaluate the internal and external factors that enable SMEs to (re)build resilience during COVID-19. In-depth interviews with owner-managers of tourism organizations in Christchurch, New Zealand reveal several themes and sub-themes that reflect not only a close influence of the owner/manager PsyCap on organizational resilience, but also the role of internal (ISC) and external (ESC) social capital in facilitating and hindering organizational resilience. As such, the study highlights the interplay between psychological and social resources in facilitating organizational recovery during COVID-19 using resilience capacities and activities. Implications for both theory and practice are offered.

Predictions of biodiversity are improved by integrating trait‐based competition with abiotic filtering

Abstract: All organisms must simultaneously tolerate the environment and access limiting resources if they are to persist. Approaches to understanding abiotic filtering and competitive interactions have generally been developed independently. Consequently, integrating those factors to predict species abundances and community structure remains an unresolved challenge. We introduce a new synthetic framework that models both abiotic filtering and competition by using functional traits. First, our framework estimates species carrying capacities along abiotic gradients. Second, it estimates pairwise competitive interactions as a function of species trait differences. Applied to the study of a complex wetland community, our combined approach more than doubles the explained variance of species abundances compared to a model of abiotic tolerances alone. Trait-based integration of competitive interactions and abiotic filtering improves our ability to predict species abundances, bringing us closer to more accurate predictions of biodiversity structure in a changing world.

Prosocial behavior toward machines.

Abstract: Building on the computers are social actors framework, we provide an overview of research demonstrating that humans behave prosocially toward machines. In doing so, we outline that similar motivational and cognitive processes play a role when people act in prosocial ways toward humans and machines. These include perceiving the machine as somewhat human, applying social categories to the machine, being socially influenced by the machine, and experiencing social emotions toward the machine. We conclude that studying prosocial behavior toward machines is important to facilitate proper functioning of human–machine interactions. We further argue that machines provide an interesting yet underutilized resource in the study of prosocial behavior because they are both highly controllable and humanlike.

A critical examination of models of annual‐plant population dynamics and density‐dependent fecundity

Abstract: Mathematical models serve many purposes in biology. Each and every model is a necessary simplification of reality, and, as simplifications, these models are also wrong by definition. And yet there are many ways to be wrong, and some of these are a much greater concern than others. For example, a paradoxical model-based prediction may simply be puzzling whereas unphysical variables (e.g. negative amounts of time or temperatures below absolute zero) and nonbiological variables (e.g. negative abundances or negative feeding rates) should be avoided altogether. Here I analyse a discrete-time model of annual-plant population dynamics and three phenomenological models for density-dependent fecundity. These phenomenological models are generally interchanged solely on the basis of their statistical fit to data. On the other hand, I highlight ways in which their phenomenological basis hampers our ability to capture known aspects of annual-plant biology. I then demonstrate how to specify a more flexible, biologically appropriate model and illustrate this model's behaviour and interpretation in single-species and multi-species contexts. By constructing this generative model for annual-plant population dynamics, I can also demonstrate how and why emergent phenomena, such as negative density dependence, emerge. Although my focus is on a model applied to annual plants, the biological implications extend to modelling any species with a discrete life cycle and nonoverlapping generations. More broadly, my exploration here showcases that there are many more criteria with which we could, and arguably should, ground-truth mathematical models across biology.

Conceptualizing post-disaster entrepreneurial decision-making: Prediction and control under extreme environmental uncertainty

Abstract: Understanding post-disaster entrepreneurial decision-making is crucial to the disaster recovery process. Such knowledge helps in the motivation of entrepreneurial actions that could restore disrupted entrepreneurial activities resulting from economic shock due to disasters. Notwithstanding that post-disaster environment is characterised by risk and uncertainty, entrepreneurs have demonstrated resilience. Effectuation and causation logics have presented the entrepreneurial process with pragmatic principles that make entrepreneurial decision-making feasible in an environment laden with all manner of constraints. Recent development in the field of entrepreneurship has seen the growth of effectual entrepreneurial research; however, a systematic understanding of how effectuation and causation logics contribute to post-disaster entrepreneurial decision-making is still largely needed.