title: Fatty acid biomarkers reveal landscape influences on linkages between aquatic and terrestrial food webs

authors: Burdon, Frank

subjects: fatty acids

abstract: Stream and riparian habitats are meta-ecosystems that can be strongly connected via the emergence of aquatic insects, which form an important prey subsidy for terrestrial consumers. Anthropogenic perturbations that impact these habitats may indirectly propagate across traditional ecosystem boundaries, thus weakening aquatic-terrestrial food web linkages. We investigated how algal production, aquatic invertebrates, and terrestrial spiders influence cross-ecosystem connectivity in temperate streams across four European catchments with varying levels of human disturbance. We used fatty acid biomarkers to measure putative aquatic linkages to riparian spiders. Variation-partitioning analysis indicated that aquatic insect dispersal traits explained a relatively large proportion of variability in the fatty acid profile of spiders. Trophic connectivity, as measured by the proportion of the polyunsaturated fatty acid eicosapentaenoic acid (EPA) and the ratio of EPA to its chemical precursor, alpha-linolenic acid (ALA), was positively associated with abundances of “aerial active” dispersing aquatic insects. However, this positive influence was also associated with changes in environmental context and arachnid beta diversity. Structural equation modeling disentangled how aquatic insect communities influence trophic connectivity with riparian predators after accounting for biological and environmental contingencies. Our results show how subsidies of stream insects are a putative source of essential fatty acids for adjacent terrestrial food webs. Catchment-wide impacts indirectly propagated to the local scale through impacts on aquatic invertebrate communities, thus affecting stream-riparian food webs. Increased riparian tree cover enhanced stream insect subsidies via dispersal traits despite reducing aquatic primary production through shading. Consequently, ecosystem properties such as woody riparian buffers that increase aquatic-terrestrial trophic connectivity have the potential to affect a wide range of consumers in modified landscapes.

text: Fatty acid biomarkers reveal landscape influences on linkages between aquatic and terrestrial food webs Stream and riparian habitats are meta-ecosystems that can be strongly connected via the emergence of aquatic insects, which form an important prey subsidy for terrestrial consumers. Anthropogenic perturbations that impact these habitats may indirectly propagate across traditional ecosystem boundaries, thus weakening aquatic-terrestrial food web linkages. We investigated how algal production, aquatic invertebrates, and terrestrial spiders influence cross-ecosystem connectivity in temperate streams across four European catchments with varying levels of human disturbance. We used fatty acid biomarkers to measure putative aquatic linkages to riparian spiders. Variation-partitioning analysis indicated that aquatic insect dispersal traits explained a relatively large proportion of variability in the fatty acid profile of spiders. Trophic connectivity, as measured by the proportion of the polyunsaturated fatty acid eicosapentaenoic acid (EPA) and the ratio of EPA to its chemical precursor, alpha-linolenic acid (ALA), was positively associated with abundances of “aerial active” dispersing aquatic insects. However, this positive influence was also associated with changes in environmental context and arachnid beta diversity. Structural equation modeling disentangled how aquatic insect communities influence trophic connectivity with riparian predators after accounting for biological and environmental contingencies. Our results show how subsidies of stream insects are a putative source of essential fatty acids for adjacent terrestrial food webs. Catchment-wide impacts indirectly propagated to the local scale through impacts on aquatic invertebrate communities, thus affecting stream-riparian food webs. Increased riparian tree cover enhanced stream insect subsidies via dispersal traits despite reducing aquatic primary production through shading. Consequently, ecosystem properties such as woody riparian buffers that increase aquatic-terrestrial trophic connectivity have the potential to affect a wide range of consumers in modified landscapes.

year: 2025

title: An economic analysis of hospital costs in New Zealand

authors: Tatchell, Philip Michael

abstract: The main purpose of this study is to apply economic principles and methods to the analysis of New Zealand’s hospital services in order to ascertain how the costs of providing those services varies among hospitals and over time. Achievement of this objective at the same time enables an assessment to be made of the relevance of the various theoretical models and empirical techniques that have been employed in recent studies of hospital costs in other countries.
Attention in the initial chapters is devoted to identifying and assessing the quantitative importance of the factors responsible for the rapid and accelerating cost increases associated with the provision of hospital services in recent years. Two main groups of factors are identified - demand and supply-related - and their relative cost impacts are tested first by means of a descriptive historical analysis, and then, following the development of a general behavioural model of hospital cost inflation, by means of econometric techniques.

The results of the estimation process indicate that rising hospital costs are largely due to changes on the supply side, particularly to the rising cost, quantity and quality of the labour and non-labour inputs used by hospitals. Demand variables, particularly changing length of stay and the changing diagnostic mix of patients treated in hospital, are also shown to have had an important, though less substantial impact on hospital cost levels. 
The second part of the study is devoted to identifying and examining the factors that give rise to variations in costs among hospitals at a given point in time. Three main groups of factors are identified - patient or output characteristics, institutional characteristics and utilisation levels, and their relative importance in explaining the interhospital cost variations is tested by means of econometric techniques.
The results indicate that variations in the average costs of hospital care are largely explained by the types of patient treated, both by age and diagnosis, by the length of time the patient stayed in hospital, and by the teaching status of the hospital. Considerable attention in this section is also devoted to establishing whether economies of scale exist in New Zealand’s hospital industry and to developing and testing a number of alternative measures of hospital output based on similar measures employed in earlier overseas studies.

A number of implications for policy and for further research arise from the findings. On the cost inflation side apart from suggesting possible ways in which to combat and control the rapid rise in hospital costs, considerable emphasis is placed on the need both for more rigorous evaluation of alternative hospital expenditure programmes and for more and better planning of all hospital and health services. Future research, it is argued, should be directed towards assessing the costs and benefits of particular hospital programmes with a view to ensuring the most efficient and effective utilisation of the scarce resources available for hospital care in New Zealand.
On the cost variation side a revised system of allocating finance to Hospital Boards is advocated which would take into account the various differences among hospitals found to be responsible for the wide variations in their average costs. Introduction of such a population-based allocation system would, it is maintained, ensure that the desired objective of an equitable distribution of resources throughout New Zealand is achieved. Further research is required firstly, to develop a simple yet reliable means of accounting for interboard case-mix differences; secondly, to assess more accurately the nature and extent of the impact of teaching on hospital costs; and finally, to ensure that the economies of scale that appear to exist in New Zealand’s hospital industry are fully exploited.

text: An economic analysis of hospital costs in New Zealand The main purpose of this study is to apply economic principles and methods to the analysis of New Zealand’s hospital services in order to ascertain how the costs of providing those services varies among hospitals and over time. Achievement of this objective at the same time enables an assessment to be made of the relevance of the various theoretical models and empirical techniques that have been employed in recent studies of hospital costs in other countries.
Attention in the initial chapters is devoted to identifying and assessing the quantitative importance of the factors responsible for the rapid and accelerating cost increases associated with the provision of hospital services in recent years. Two main groups of factors are identified - demand and supply-related - and their relative cost impacts are tested first by means of a descriptive historical analysis, and then, following the development of a general behavioural model of hospital cost inflation, by means of econometric techniques.

The results of the estimation process indicate that rising hospital costs are largely due to changes on the supply side, particularly to the rising cost, quantity and quality of the labour and non-labour inputs used by hospitals. Demand variables, particularly changing length of stay and the changing diagnostic mix of patients treated in hospital, are also shown to have had an important, though less substantial impact on hospital cost levels. 
The second part of the study is devoted to identifying and examining the factors that give rise to variations in costs among hospitals at a given point in time. Three main groups of factors are identified - patient or output characteristics, institutional characteristics and utilisation levels, and their relative importance in explaining the interhospital cost variations is tested by means of econometric techniques.
The results indicate that variations in the average costs of hospital care are largely explained by the types of patient treated, both by age and diagnosis, by the length of time the patient stayed in hospital, and by the teaching status of the hospital. Considerable attention in this section is also devoted to establishing whether economies of scale exist in New Zealand’s hospital industry and to developing and testing a number of alternative measures of hospital output based on similar measures employed in earlier overseas studies.

A number of implications for policy and for further research arise from the findings. On the cost inflation side apart from suggesting possible ways in which to combat and control the rapid rise in hospital costs, considerable emphasis is placed on the need both for more rigorous evaluation of alternative hospital expenditure programmes and for more and better planning of all hospital and health services. Future research, it is argued, should be directed towards assessing the costs and benefits of particular hospital programmes with a view to ensuring the most efficient and effective utilisation of the scarce resources available for hospital care in New Zealand.
On the cost variation side a revised system of allocating finance to Hospital Boards is advocated which would take into account the various differences among hospitals found to be responsible for the wide variations in their average costs. Introduction of such a population-based allocation system would, it is maintained, ensure that the desired objective of an equitable distribution of resources throughout New Zealand is achieved. Further research is required firstly, to develop a simple yet reliable means of accounting for interboard case-mix differences; secondly, to assess more accurately the nature and extent of the impact of teaching on hospital costs; and finally, to ensure that the economies of scale that appear to exist in New Zealand’s hospital industry are fully exploited.

year: 1977

title: Supervising research in Māori cultural contexts: a decolonizing, relational response

authors: Berryman, Mere

abstract: We have collaborated for 25 years as indigenous Māori and non- Māori researchers undertaking research with Māori families, their schools and communities. We have endeavored to meet our responsibilities to the Māori people (indigenous inhabitants of New Zealand) and communities with whom we have researched, as well as meet the requirements and responsibilities of our academic institutions. In this paper, we reflect on the implications of these responsibilities for our work as supervisors of master’s and doctoral students (Māori and non-Māori) who seek to draw on decolonizing methodologies as they undertake research in Māori cultural contexts. We draw on the experiences and interactions we have had with four different postgraduate students whose research on improving educational outcomes for Māori students has required them to engage and participate in Māori cultural contexts.

text: Supervising research in Māori cultural contexts: a decolonizing, relational response We have collaborated for 25 years as indigenous Māori and non- Māori researchers undertaking research with Māori families, their schools and communities. We have endeavored to meet our responsibilities to the Māori people (indigenous inhabitants of New Zealand) and communities with whom we have researched, as well as meet the requirements and responsibilities of our academic institutions. In this paper, we reflect on the implications of these responsibilities for our work as supervisors of master’s and doctoral students (Māori and non-Māori) who seek to draw on decolonizing methodologies as they undertake research in Māori cultural contexts. We draw on the experiences and interactions we have had with four different postgraduate students whose research on improving educational outcomes for Māori students has required them to engage and participate in Māori cultural contexts.

year: 2017