title: Sediment transport in the Firth of Thames mangrove forest, New Zealand

authors: Lovett, Nicola Jane

subjects: Sediment transport

abstract: Mangroves provide a unique habitat for many species.  In addition to being biologically significant ecosystems, mangroves help protect coastal areas through the dissipation of tidal currents and wave energy.  However, mangroves are unpopular with some communities in New Zealand and removal of them is often considered in management strategies.  In order to effectively manage these vegetated coastal areas and predict growth and/or decline of mangrove systems, it is necessary to have a detailed understanding of how the hydrodynamic processes within forests influence sediment transport and deposition.  

A 6-day long experiment was conducted in the Firth of Thames mangrove forest to examine hydrodynamic processes that influence sediment transport from the intertidal mudflat across the fringing region of the mangrove forest into the forest itself.  A unique deployment system was utilised to minimise environmental disturbance during the data collection process at 5 sites.  Site 1 was located on the mudflat and site 2 was in the fringe area (i.e. the boundary between flat and forest).  Sites 3 to 5 were located at increasing distances inside the forest.  Results indicate wave activity causes a net offshore flux of sediment at site 1 (approximately 850 kg/m2 over the duration of the experiment), contrary to expectations.  However, at all other sites, there was a net onshore flux of sediment from the fringe into the forest (maximum at site 4 of 113.3 kg/m2).  Minimal scour in the experiment area indicates that sediment is primarily supplied by advection from other regions of the system. 

Flocculation is a key process in cohesive sediment transport.  One of the aims of the study was to understand the controls on flocculation within this vegetated system. Despite difficulties inherent in measuring flocs, floc images were successfully collected from some sites.  An initial qualitative analysis performed on images from 2 sites (1 and 3) over 2 tides revealed a greater quantity of large flocs on the mudflat than in the forest and that in general, flocs were larger on the ebb tide.  These results imply that settling velocities on the mudflat are larger than within the forest and settling velocities are larger during ebb than flood tides.

text: Sediment transport in the Firth of Thames mangrove forest, New Zealand Mangroves provide a unique habitat for many species.  In addition to being biologically significant ecosystems, mangroves help protect coastal areas through the dissipation of tidal currents and wave energy.  However, mangroves are unpopular with some communities in New Zealand and removal of them is often considered in management strategies.  In order to effectively manage these vegetated coastal areas and predict growth and/or decline of mangrove systems, it is necessary to have a detailed understanding of how the hydrodynamic processes within forests influence sediment transport and deposition.  

A 6-day long experiment was conducted in the Firth of Thames mangrove forest to examine hydrodynamic processes that influence sediment transport from the intertidal mudflat across the fringing region of the mangrove forest into the forest itself.  A unique deployment system was utilised to minimise environmental disturbance during the data collection process at 5 sites.  Site 1 was located on the mudflat and site 2 was in the fringe area (i.e. the boundary between flat and forest).  Sites 3 to 5 were located at increasing distances inside the forest.  Results indicate wave activity causes a net offshore flux of sediment at site 1 (approximately 850 kg/m2 over the duration of the experiment), contrary to expectations.  However, at all other sites, there was a net onshore flux of sediment from the fringe into the forest (maximum at site 4 of 113.3 kg/m2).  Minimal scour in the experiment area indicates that sediment is primarily supplied by advection from other regions of the system. 

Flocculation is a key process in cohesive sediment transport.  One of the aims of the study was to understand the controls on flocculation within this vegetated system. Despite difficulties inherent in measuring flocs, floc images were successfully collected from some sites.  An initial qualitative analysis performed on images from 2 sites (1 and 3) over 2 tides revealed a greater quantity of large flocs on the mudflat than in the forest and that in general, flocs were larger on the ebb tide.  These results imply that settling velocities on the mudflat are larger than within the forest and settling velocities are larger during ebb than flood tides.

year: 2017

title: A New Zealand digital library for computer science research

authors: Witten, Ian H.

subjects: computer science

abstract: A large amount of computing literature has become available over the Internet, as university departments and research institutions have made their technical reports, preprints, and theses available electronically. Access to these items has been limited, however, by the difficulties involved in locating documents of interest. We describe a proposal for a New Zealand-based index of computer science technical reports, where the reports themselves are located in repositories that are distributed world-wide. Our scheme is unique in that it is based on indexing the full text of the technical reports, rather than on document surrogates. The index is constructed so as to minimize network traffic and local storage costs (of particular importance for geographically isolated countries like New Zealand, which incur high Internet costs). We also will provide support for bibliometric/scientometric studies of the computing literature and our users.

text: A New Zealand digital library for computer science research A large amount of computing literature has become available over the Internet, as university departments and research institutions have made their technical reports, preprints, and theses available electronically. Access to these items has been limited, however, by the difficulties involved in locating documents of interest. We describe a proposal for a New Zealand-based index of computer science technical reports, where the reports themselves are located in repositories that are distributed world-wide. Our scheme is unique in that it is based on indexing the full text of the technical reports, rather than on document surrogates. The index is constructed so as to minimize network traffic and local storage costs (of particular importance for geographically isolated countries like New Zealand, which incur high Internet costs). We also will provide support for bibliometric/scientometric studies of the computing literature and our users.

year: 1995-03

title: Risk assessment for family violence aggressors in Aotearoa New Zealand

authors: Jolliffe Simpson, Apriel D.

subjects: Family violence

abstract: In recent decades Family Violence (FV) researchers have developed risk assessment instruments to enable practitioners to identify the people who are most likely to commit FV in the future, and the families who are most likely to experience ongoing harm. Indeed, risk assessments have become a standard procedure for FV practitioners who are frequently required to make decisions with potential ramifications for families’ safety and wellbeing. Yet, despite considerable developments in risk assessment research and practice, risk assessment instruments have limitations that curb their value to FV practice. In addition, such instruments should be empirically validated, but there is limited evidence for the validity of risk assessment instruments used by agencies that respond to FV in Aotearoa New Zealand. Therefore, in this thesis, we examined the risk assessment procedures that New Zealand Police and the Integrated Safety Response (ISR) used for FV, with the purpose of contributing to the evidence base about risk assessment for FV in New Zealand and identifying strengths, weaknesses, and opportunities for improvement.
This thesis contains three manuscripts either published in or submitted to peer-reviewed academic journals; as well as supplementary chapters that support, extend, and integrate the research findings. In the first manuscript, we examined the predictive validity of risk categories from the Dynamic Risk Assessment for family violence (DYRA) and Static Assessment of Family Violence Recidivism (SAFVR)—the two risk assessment instruments that New Zealand Police use when responding to FV cases—for a sample of 2,115 cases with FV episodes reported to police in Waikato and parts of Canterbury between 1 November – 9 December 2018 (1,817 of which had complete risk categories). We examined the instruments’ ability to predict recurrence (i.e., a further FV-related call for police service) at three intervals (3 days, 12 weeks, and 24 weeks), and found both instruments had a poor ability to discriminate between aggressors who had a recurrence and those who did not, with the SAFVR outperforming the DYRA, and the DYRA performing especially poorly for non-intimate partner cases, and aggressors who were Māori or women. 
In the second manuscript, we explored the risk assessments that Integrated Safety Response (ISR) triage team members conducted for a sub-sample of 842 cases with FV episodes reported to police between 1 – 14 November 2018. We examined the relationship between the factors triage teams recorded during their risk assessments and the risk categories the teams assigned, then tested the association of both the factors and categories with recurrence and physical recurrence within 24 weeks. The predictive validity of ISR triage teams’ risk categories was comparable to the results produced for the DYRA and SAFVR in manuscript one. The ISR risk categories again performed poorly for aggressors who were women, Māori, and for non-intimate partner cases; and overall, fewer than half of the factors triage teams recorded were associated with recurrence or physical recurrence. Then, in an additional chapter, we explored the triage teams’ factors’ utility for case management and found the factors could be used to create three sub-groups of cases with potential implications for their treatment and management. 
Finally, in the third manuscript, we modeled the behavioral patterns of 2,115 aggressors with a FV episode reported to police in Waikato and parts of Canterbury between 1 November – 9 December 2018, by collecting reports for further FV episodes involving those aggressors during the two years after the index episode. We used this information to describe three latent states behind the information reported to police and identified four common pathways through the latent states over time. We concluded this manuscript by discussing changes that could contribute to improvements in how risk for FV aggressors is conceptualized, assessed, and communicated in practice.
In each chapter, we discussed the theoretical and practical implications of the findings, before integrating those findings and implications in a general discussion chapter. Taken together, the results presented herein indicate that the risk assessment instruments used in New Zealand can predict risk for FV recurrence better than chance, but that those assessments should be further developed to improve their value to FV practice and ensure they adequately capture risk for different types of FV cases and groups of people. This thesis advanced our understanding of the limitations of—and opportunities in—risk assessment research and contributed to the evidence base for risk assessment for FV in New Zealand.

text: Risk assessment for family violence aggressors in Aotearoa New Zealand In recent decades Family Violence (FV) researchers have developed risk assessment instruments to enable practitioners to identify the people who are most likely to commit FV in the future, and the families who are most likely to experience ongoing harm. Indeed, risk assessments have become a standard procedure for FV practitioners who are frequently required to make decisions with potential ramifications for families’ safety and wellbeing. Yet, despite considerable developments in risk assessment research and practice, risk assessment instruments have limitations that curb their value to FV practice. In addition, such instruments should be empirically validated, but there is limited evidence for the validity of risk assessment instruments used by agencies that respond to FV in Aotearoa New Zealand. Therefore, in this thesis, we examined the risk assessment procedures that New Zealand Police and the Integrated Safety Response (ISR) used for FV, with the purpose of contributing to the evidence base about risk assessment for FV in New Zealand and identifying strengths, weaknesses, and opportunities for improvement.
This thesis contains three manuscripts either published in or submitted to peer-reviewed academic journals; as well as supplementary chapters that support, extend, and integrate the research findings. In the first manuscript, we examined the predictive validity of risk categories from the Dynamic Risk Assessment for family violence (DYRA) and Static Assessment of Family Violence Recidivism (SAFVR)—the two risk assessment instruments that New Zealand Police use when responding to FV cases—for a sample of 2,115 cases with FV episodes reported to police in Waikato and parts of Canterbury between 1 November – 9 December 2018 (1,817 of which had complete risk categories). We examined the instruments’ ability to predict recurrence (i.e., a further FV-related call for police service) at three intervals (3 days, 12 weeks, and 24 weeks), and found both instruments had a poor ability to discriminate between aggressors who had a recurrence and those who did not, with the SAFVR outperforming the DYRA, and the DYRA performing especially poorly for non-intimate partner cases, and aggressors who were Māori or women. 
In the second manuscript, we explored the risk assessments that Integrated Safety Response (ISR) triage team members conducted for a sub-sample of 842 cases with FV episodes reported to police between 1 – 14 November 2018. We examined the relationship between the factors triage teams recorded during their risk assessments and the risk categories the teams assigned, then tested the association of both the factors and categories with recurrence and physical recurrence within 24 weeks. The predictive validity of ISR triage teams’ risk categories was comparable to the results produced for the DYRA and SAFVR in manuscript one. The ISR risk categories again performed poorly for aggressors who were women, Māori, and for non-intimate partner cases; and overall, fewer than half of the factors triage teams recorded were associated with recurrence or physical recurrence. Then, in an additional chapter, we explored the triage teams’ factors’ utility for case management and found the factors could be used to create three sub-groups of cases with potential implications for their treatment and management. 
Finally, in the third manuscript, we modeled the behavioral patterns of 2,115 aggressors with a FV episode reported to police in Waikato and parts of Canterbury between 1 November – 9 December 2018, by collecting reports for further FV episodes involving those aggressors during the two years after the index episode. We used this information to describe three latent states behind the information reported to police and identified four common pathways through the latent states over time. We concluded this manuscript by discussing changes that could contribute to improvements in how risk for FV aggressors is conceptualized, assessed, and communicated in practice.
In each chapter, we discussed the theoretical and practical implications of the findings, before integrating those findings and implications in a general discussion chapter. Taken together, the results presented herein indicate that the risk assessment instruments used in New Zealand can predict risk for FV recurrence better than chance, but that those assessments should be further developed to improve their value to FV practice and ensure they adequately capture risk for different types of FV cases and groups of people. This thesis advanced our understanding of the limitations of—and opportunities in—risk assessment research and contributed to the evidence base for risk assessment for FV in New Zealand.

year: 2023