title: Enhanced sample preparation for quantitation of microcystins by matrix-assisted laser desorption/ionisation–time of flight mass spectrometry

authors: Puddick, Jonathan

subjects: MALDI–TOF mass spectrometry

abstract: Introduction: Microcystins (MCs) are a group of cyanotoxins which pose a serious health threat when present in aquatic systems. Quantitative analysis of MCs by matrix-assisted laser desorption/ionisation–time of flight (MALDI–TOF) mass spectrometry has potential for the processing of large numbers of samples quickly and economically. The existing method uses an expensive internal standard and protocols that are incompatible with automated sample preparation and data acquisition.
Objective: To produce a MALDI–TOF sample preparation technique for the quantitation of MCs that not only maintains reproducibility and sensitivity, but is also compatible with an automated work-flow.
Methodology: Seven different MALDI–TOF sample preparations were assessed for signal reproducibility (coefficient of variation) and sensitivity (method detection limit) using a cost-effective internal standard (angiotensin I). The best preparation was then assessed for its quantitative performance using three different MC congeners ([Dha7] MC-LR, MC-RR and MC-YR).
Results: The sensitivity of six of the preparations was acceptable, as was the reproducibility for two thin-layer preparations performed on a polished steel target. Both thin-layer preparations could be used with a MALDI-TOF mass spectrometer that automatically acquires data, and one could be used in an automated sample preparation work-flow. Further investigation using the thin-layer spot preparation demonstrated that linear quantification of three different MC congeners was possible.
Conclusion: The study demonstrates that with different sample preparation methods and modern instrumentation, large numbers of samples can be analysed rapidly for MCs at low cost.

text: Enhanced sample preparation for quantitation of microcystins by matrix-assisted laser desorption/ionisation–time of flight mass spectrometry Introduction: Microcystins (MCs) are a group of cyanotoxins which pose a serious health threat when present in aquatic systems. Quantitative analysis of MCs by matrix-assisted laser desorption/ionisation–time of flight (MALDI–TOF) mass spectrometry has potential for the processing of large numbers of samples quickly and economically. The existing method uses an expensive internal standard and protocols that are incompatible with automated sample preparation and data acquisition.
Objective: To produce a MALDI–TOF sample preparation technique for the quantitation of MCs that not only maintains reproducibility and sensitivity, but is also compatible with an automated work-flow.
Methodology: Seven different MALDI–TOF sample preparations were assessed for signal reproducibility (coefficient of variation) and sensitivity (method detection limit) using a cost-effective internal standard (angiotensin I). The best preparation was then assessed for its quantitative performance using three different MC congeners ([Dha7] MC-LR, MC-RR and MC-YR).
Results: The sensitivity of six of the preparations was acceptable, as was the reproducibility for two thin-layer preparations performed on a polished steel target. Both thin-layer preparations could be used with a MALDI-TOF mass spectrometer that automatically acquires data, and one could be used in an automated sample preparation work-flow. Further investigation using the thin-layer spot preparation demonstrated that linear quantification of three different MC congeners was possible.
Conclusion: The study demonstrates that with different sample preparation methods and modern instrumentation, large numbers of samples can be analysed rapidly for MCs at low cost.

year: 2011

title: Forecasting h(m)otel guest nights in New Zealand

authors: Lim, Christine

subjects: lodging industry

abstract: The purpose of this paper is to highlight some time series models which hotel and motel industry practitioners could use to forecast guest nights. Given their considerable practicality, the lodging industry can easily benefit from using these models as forecasts can be obtained at low cost for effective management and planning. Monthly observations are used for estimating the model from 1997(1) to 2006(12). The Holt–Winters and Box–Jenkins ARMA models are able to forecast guest night demand accurately as 99% of the variations in the guest night forecast are associated with variations in actual guest nights in 2007.

text: Forecasting h(m)otel guest nights in New Zealand The purpose of this paper is to highlight some time series models which hotel and motel industry practitioners could use to forecast guest nights. Given their considerable practicality, the lodging industry can easily benefit from using these models as forecasts can be obtained at low cost for effective management and planning. Monthly observations are used for estimating the model from 1997(1) to 2006(12). The Holt–Winters and Box–Jenkins ARMA models are able to forecast guest night demand accurately as 99% of the variations in the guest night forecast are associated with variations in actual guest nights in 2007.

year: 2009

title: Unpacking media narratives: Racism and problematic reasonings

authors: Tan, Kyle K. H.

abstract: In this research brief, we present summaries of four case studies of racism in mainstream and social media in Aotearoa. Through a series of carefully selected datasets sourced from TV episodes (Police TEN 7), print media such as news articles (including Northland checkpoints), and tweets (Three Waters reform), we outline how Māori are represented across these mediums. With an expert in language modelling on our team, we analysed large datasets that give us sufficient statistical power to infer specific Māori discourses on respective platforms. Further, we examined key themes that characterise how Māori are represented in the media and signal the scale of anti-Māori attacks. For instance, we found that the predominant discussion on Three Waters reform on Twitter focused on ‘conflict’ (distrust towards government; 33%) and ‘capability’ (questioning the credibility of the reform; 23%) rather than its core intention of promoting water ‘safety’ (7%). The modelling analysis was supplemented by in-depth qualitative analysis that integrates anti-Māori themes (Moewaka-Barnes et al., 2012) and problematic reasoning tactics (Sturgill, 2021) to elucidate how false, deficit-based rhetoric about Māori is deployed to fuel racism and disinformation. In summary, our findings reinforce Kupu Taea’s call for new media sectors to integrate Te Tiriti o Waitangi into their practices to safeguard Māori and other minoritised groups who are likely to be at the fore of racist attacks.

text: Unpacking media narratives: Racism and problematic reasonings In this research brief, we present summaries of four case studies of racism in mainstream and social media in Aotearoa. Through a series of carefully selected datasets sourced from TV episodes (Police TEN 7), print media such as news articles (including Northland checkpoints), and tweets (Three Waters reform), we outline how Māori are represented across these mediums. With an expert in language modelling on our team, we analysed large datasets that give us sufficient statistical power to infer specific Māori discourses on respective platforms. Further, we examined key themes that characterise how Māori are represented in the media and signal the scale of anti-Māori attacks. For instance, we found that the predominant discussion on Three Waters reform on Twitter focused on ‘conflict’ (distrust towards government; 33%) and ‘capability’ (questioning the credibility of the reform; 23%) rather than its core intention of promoting water ‘safety’ (7%). The modelling analysis was supplemented by in-depth qualitative analysis that integrates anti-Māori themes (Moewaka-Barnes et al., 2012) and problematic reasoning tactics (Sturgill, 2021) to elucidate how false, deficit-based rhetoric about Māori is deployed to fuel racism and disinformation. In summary, our findings reinforce Kupu Taea’s call for new media sectors to integrate Te Tiriti o Waitangi into their practices to safeguard Māori and other minoritised groups who are likely to be at the fore of racist attacks.

year: 2025