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The physical health and premature mortality of Indigenous Māori following first-episode psychosis diagnosis: A 15-year follow-up study
No full textBackground:
People experiencing psychosis are at greater risk of physical health conditions and premature mortality. It is likely that Indigenous Māori youth, who experience additional systemic inequities caused by settler-colonisation, face even greater physical health and mortality risks following a diagnosis of first-episode psychosis.
Objective:
Compare Māori and non-Māori for risk of hospitalisation and mortality for up to 15 years following first-episode psychosis diagnosis.
Methods:
A cohort (N = 14,122) of young people (16–24 years) with first-episode psychosis diagnosis between 2001 and 2019 were identified. Using crude Kaplan–Meier and adjusted Cox proportional hazards models, Māori (n = 5211) and non-Māori (n = 8911) were compared on hospitalisation and mortality outcomes for up to 15 years.
Results:
In the 15 years following first-episode psychosis diagnosis, Māori had higher adjusted risk of all-cause mortality (hazard ratio = 1.21, 95% confidence interval = [1.01, 1.45]), hospitalisation with diabetes (hazard ratio = 1.44, 95% confidence interval = [1.15, 1.79]), injury/poisoning (hazard ratio = 1.11, 95% confidence interval = [1.05, 1.16]), general physical health conditions (hazard ratio = 1.07, 95% confidence interval = [1.02, 1.13]) and also appeared to be at greater risk of cardiovascular hospitalisations (hazard ratio = 1.34, 95% confidence interval = [0.97, 1.86]). Kaplan–Meier plots show hospitalisation and mortality inequities emerging approximately 4–7 years following first-episode psychosis diagnosis.
Conclusions:
Māori are at greater risk for hospitalisation and premature mortality outcomes following first-episode psychosis. Early screening and intervention, facilitated by culturally safe health service delivery, is needed to target these inequities early
How energetic constraints shape plant and soil invertebrate communities
No full textThe Metabolic Theory of Ecology (MTE) and its predictions of the scaling of average population body mass with abundance and energy use are some of the most widely observed and studied biological relationships. However, the scaling exponent value of these relationships have been widely debated and found to vary considerably among various ecological communities and the ecosystems they occupy. Additionally, adherence to MTE predictions is widely contingent on its underlying assumptions and the variables used to describe these relationships. My thesis aims to provide a comprehensive analysis of the size–density and size–energy use scaling relationships of soil invertebrate and tree communities to shed light on the environmental and biological factors underpinning their observed exponents. To do this, I tested whether predictions of size–density scaling derived from MTE are dependent on ecosystem reassembly processes throughout succession and organism life history traits within trees and soil invertebrates. I also analysed size–density and size–energy use scaling in soil invertebrate food webs across four geographical locations to investigate the universality of size–density scaling relationships and their likelihood of accurately indicating energetic equivalence in soil communities of primary and secondary consumers. Additionally, I compared two measures of energy use to investigate size–energy use relationships: population metabolism and trophic energy fluxes in food webs. My findings suggested that size–density scaling, although related to energy use in ecological communities, is likely a poor indicator of energetic equivalence alone, but in combination with size–energy use scaling relationships can provide powerful insights into the energetic structuring of these communities. Additionally, size–density scaling exponents vary considerably across ecosystem succession and organism life form, and expectations should reflect these conditions. Energy flux as an estimate of energy use within communities for analysing size–energy use relationships was a more precise estimate compared to metabolism as it better captures the true energetic demands of organisms, particularly for secondary consumers which face stronger energetic constraints. Finally, analytically estimating energy fluxes with a trophic level–specific focus better captured the differences in patterns of energy use between these trophic levels compared to when they were pooled. Ultimately, this thesis provides new directions for exploring energetic equivalence in terrestrial communities
Nutrient removal by algal polyculture in dairy farm effluent
No full textNutrient pollution from dairy farm effluent, particularly nitrogen (N) and phosphorus (P), significantly contributes to environmental degradation and eutrophication, necessitating effective bioremediation strategies. This study explores the efficacy of algae polyculture E3 in remediating dairy farm wastewater, focusing on nutrient removal and algal growth. Conducted over a 28-day period, the research compares the bioremediation capabilities of algae polyculture in autoclaved and non-autoclaved effluent samples. Findings reveal that algae polyculture demonstrates superior bioremediation performance in non-autoclaved conditions, with growth rates ranging from 8.07 to 10.13 mg L-1 d-1. The algal polyculture achieved significant nutrient removal, eliminating 90.9% of ammonium (NH₄⁺) and 99.1% of phosphate (PO₄³⁻), highlighting its potential in mitigating nutrient pollution. The study underscores the importance of operational conditions, as non-autoclaved environments fostered more robust algal growth and nutrient uptake. Further, the research involved the optimisation of the model data, leading to improved accuracy in simulating the biological removal processes. The optimised model better reflects real-world bioremediation dynamics, facilitating more reliable predictions of algal performance and nutrient cycling. Additionally, the study identifies a 10-day hydraulic retention time (HRT) as optimal for balancing algal biomass growth with nutrient removal, addressing common challenges such as algal washout and inefficiency in nutrient uptake. In conclusion, the findings advocate for the application of algae polyculture E3 in the bioremediation of dairy farm effluent, proposing a sustainable approach to addressing the critical issue of nutrient pollution. By optimizing conditions for algal growth and nutrient removal, this research contributes to the development of more effective environmental management practices
The language of the soul in narrative therapy: Spirituality in clinical theory and practice [Book review]
No full textTime varying risk aversion and its connectedness: Evidence from cryptocurrencies
No full textChanging patterns of risk aversion may follow a non-linear counter-cyclical process. However, the evidence so far has not considered developing cryptocurrency markets. Given some unique features of cryptocurrencies, it is interesting to distinguish how these assets differ from traditional products. This paper investigates the time effects of periodicity on risk aversion for a selection of major cryptocurrencies compared to major financial assets. Significant periodic time-varying patterns are identified when analysing risk aversion. Further, bilateral and bidirectional Granger causalities are identified within cryptocurrencies, as well as between cryptocurrencies and traditional financial assets. Bitcoin is identified as a leading information transmitter of the spillover of risk aversion upon other cryptocurrencies, while estimated risk aversion of traditional financial markets plays a dominant role in the spillover processes upon the cryptocurrency cluster. The latter finding presents further evidence of developing cryptocurrency market maturity. The COVID-19 pandemic is found to have significantly influenced the connectedness of risk aversion among cryptocurrency and traditional financial markets
Selenium speciation studies in cancer patients to evaluate the responses of biomarkers of selenium status to different selenium compounds
No full textThis work presents the first systematic comparison of selenium (Se) speciation in plasma from cancer patients treated orally with three Se compounds (sodium selenite, SS; L-selenomethionine, SeMet; or Se-methylselenocysteine, MSC) at 400 µg/day for 28 days. The primary goal was to investigate how these chemical forms of Se affect the plasma Se distribution, aiming to identify the most effective Se compound for optimal selenoprotein expression. This was achieved using methodology based on HPLC-ICP-MS after sample preparation/fractionation approaches. Measurements of total Se in plasma samples collected before and after 4 weeks of treatment showed that median total Se levels increased significantly from 89.6 to 126.4 µg kg−1 Se (p < 0.001), particularly when SeMet was administered (190.4 µg kg−1 Se). Speciation studies showed that the most critical differences between treated and baseline samples were seen for selenoprotein P (SELENOP) and selenoalbumin after administration with MSC (p = 5.8 × 10−4) and SeMet (p = 6.8 × 10−5), respectively. Notably, selenosugar-1 was detected in all low-molecular-weight plasma fractions following treatment, particularly with MSC. Two different chromatographic approaches and spiking experiments demonstrated that about 45% of that increase in SELENOP levels (to ~ 8.8 mg L−1) with SeMet is likely due to the non-specific incorporation of SeMet into the SELENOP affinity fraction. To the authors’ knowledge, this has not been reported to date. Therefore, SELENOP is probably part of both the regulated (55%) and non-regulated (45%) Se pools after SeMet administration, whereas SS and MSC mainly contribute to the regulated one
Dairy Effluent Steroidal Hormones Characteristics and Treatment by Anaerobic Digestion (Covered Anaerobic Pond) and Biochar
No full textEndocrine disrupting compounds such as estrogenic steroid hormones (ESHs) are problematic when present in waterways in terms of both the health of the ecosystem and downstream water treatment. Dairy farms are some of the largest contributors to ESHs in the environment. This study focused on a farm located in the Waikato region, New Zealand, which housed 550, primarily grass-fed dairy cows. The farm included a rotary milking shed, feed pad, sump, covered anaerobic pond and storage pond, with effluent and sludge being applied to land. In this study concentrations of the conjugated and unconjugated ESHs, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2) and estrone (E1), in both dissolved and solid phases of dairy shed effluent, and covered anaerobic pond sludge and effluent, were measured from grab samples over a period of nine months. These were used to investigate seasonal variation and performance of the covered anaerobic pond in removing the ESHs and their conversion from one form into another. Previously published methods of ESH analysis were validated and adapted for ESH analysis in dissolved and solid phases, and a new enzymatic method for conjugate ESH analysis was tested and used. In addition, the effect of dosing the effluent with biochar was examined on ESH removal. A covered anaerobic pond model was developed to examine the efficacy of a dairy farm-based covered anaerobic pond treatment system to settle, transform, absorb and remove ESHs. The model was calibrated utilising ESH measurements and used to examine the effect of biochar addition and operational parameters on ESH removal.
Overall ESH concentrations in the covered anaerobic pond influent, sludge and effluent were 4,171 ng/L, 93,601 ng/L and 4,346 ng/L respectively. ESH concentrations peaked in dairy shed effluent during April and July, which correlated with the late pregnancy and calving periods on the farm. The mean organic carbon normalised adsorption coefficient (Koc) for ESHs in the samples from the pond treatment system ranged between 3.06 mL/g to 3.78 mL/g, comparable with published values in soil and wastewater sludge. Up to 99% of the total mass of ESHs in the sludge and between 70-80 % in influent and effluent were retained in the solids phase. The predominant ESH in the influent samples was 17α-E2 (2,869 ng/L), but E1 predominated in the sludge (85,414 ng/L) and in the effluent (3,140 ng/L). The dissolved and solid phases of dairy shed effluent contained the highest relative proportions of conjugated ESHs with means of 25.1 % and 3.38 % respectively and corresponding mean concentrations of 113 ng/L and 137 ng/L. In contrast, sludge and effluent samples (dissolved and solid phases) from the covered anaerobic pond contained smaller relative proportions of conjugated ESHs, 0.90 % and 1.21 %, and 7.17 % and 0.43 % respectively and corresponding mean concentrations of 6.65 ng/L and 967 ng/L, and 52.5 ng/L and 19.7 ng/L respectively. These results demonstrate the importance of considering the solid fraction within effluent treatment systems when analysing ESHs, otherwise estrogenic load can be greatly underestimated. The conjugated ESHs were present in both the dissolved and solid phases of all samples collected, indicating that conjugated ESHs are persistent and can pass through anaerobic treatment systems contributing to estrogenic load once applied to pasture, and potentially leach into groundwater or migrate to nearby surface waters. Overall anaerobic treatment of dairy waste decreased the contribution of 17α-E2 and 17-E2 while increasing that of E1, however, 17-E2 was the main contributor to total estrogenicity.
The calibration of the model developed provided a good fit with experimental data with an R2 of 0.98-0.99. Addition of biochar into dairy shed effluent and the model covered anaerobic pond system resulted in an 89 % reduction of free ESHs but had a minimal impact on conjugated ESH. Addition of biochar increased the solid phase ESH concentration by 19 % settling out into the sludge and reducing overall estrogenic load in the effluent. Operational factors such as higher influent flow rates and sludge accumulation negatively impacted the covered anaerobic pond ESH removal performance. Sludge accumulation and short-circuiting caused by infrequent removal and shallow depth of the covered anaerobic pond system resulted in mixing of fresh influent with the upper layer of pond sludge, leading to decreased removal efficiency. To enhance the covered anaerobic pond system's performance, increasing the retention time and reducing sludge carry over by increasing pond volume and depth, resulted in ESH removal increasing to 67.9 % (no biochar) and 73.0 % (with biochar), and estrogenicity reduction improving to 70.4 % (no biochar) and 73.5 % (with biochar)
The mating systems and introgression of New Zealand fishing spiders (Dolomedes)
No full textMating systems describe the number of mates different sexes in a species have in their lifetime. Mating systems are key to sexual selection and the evolution of species, as a mating system sets the rules for future evolution and sexual conflict. Spiders show a wide variety of mating systems and extreme adaptations and behaviours are associated with the evolution of monogynous (males mate once in their life) mating systems, including males breaking their genitalia and sacrificing themselves to be eaten by their mate.
Another process that is highly influential on evolution is introgression, the movement of genes from one species to another. This generally occurs through species mating to produce hybrids which then facilitate gene transfer. Despite requiring two different species to interbreed, introgression is often not investigated through the lens of mating behaviours and how these can facilitate or limit introgression.
Dolomedes aquaticus and D. minor are fishing spiders endemic to New Zealand. Their mating systems and behaviour are undescribed, but members of this genus in other parts of the world are known for their extreme mating behaviour including obligate monogyny, spontaneous male death and sexual cannibalism. Previous genomic work on D. aquaticus and D. minor revealed a one-way and geographically limited introgression occurring between the two species. That is, genes are being transferred between the two species, but only via D. aquaticus females mating with D. minor males; and only in the extreme south of the two species’ shared range.
In this thesis I investigated the mating systems and introgression of D. aquaticus and D. minor, using laboratory experiments, field surveys, and 3D morphometrics. I found D. aquaticus females will generally only mate once, followed by a syndrome of aggression after mating, whilst males will mate multiply. D. minor mating is typified by low probability of mating for males and females, but potential for multiple mating in both sexes, rapid escape behaviour by males following copulation, and genital damage. I also found that the two species are able to meet outside of the Introgression Zone, making it unlikely that habitat plays a key role in the introgression. Instead, my results suggest behaviour plays a significant role in limiting the introgression, with male-choice controlling the geographic element and female-choice the one-way element. Using micro-computed tomography and 3D morphometrics I analysed the potential role of genital shape in this introgression. Whilst the genitalia of the two species were quantifiably different, there was little evidence that genital shape limits the introgression.
The results of this thesis show that closely related species can have drastically different mating systems, showing the strong impact sexual selection can have on the behaviour of species. They also highlight the importance of behaviour to promoting and limiting introgression between species. Future work on these species should include investigation of sperm dynamics, the rapid copulation behaviour of D. minor, and testing the effectiveness of genital plugging to reduce sperm competition in D. minor