title: A comparison of different approaches for measuring denitrification rates in a nitrate removing bioreactor

authors: Warneke, Sören

subjects: Denitrification

abstract: Denitrifying woodchip bioreactors (denitrification beds) are increasingly used to remove excess nitrate (NO₃⁻) from point-sources such as wastewater effluent or subsurface drains from agricultural fields. NO₃⁻ removal in these beds is assumed to be due to microbial denitrification but direct measurements of denitrification are lacking. Our objective was to test four different approaches for measuring denitrification rates in a denitrification bed that treated effluent discharged from a glasshouse. We compared these denitrification rates with the rate of NO₃⁻ removal along the length of the bed. The NO₃⁻ removal rate was 8.73 ± 1.45 g m⁻³ d⁻¹. In vitro acetylene inhibition assays resulted in highly variable denitrification rates (DRAI) along the length of the bed and generally 5 times greater than the measured (NO₃⁻- N removal rate. An in situ push–pull test, where enriched ¹⁵N- NO₃⁻was injected into 2 locations along the bed, resulted in rates of 23.2 ± 1.43 g N m⁻³ d⁻¹ and 8.06 ± 1.64 g N m⁻³ d⁻¹. The denitrification rate calculated from the increase in dissolved N2 and N2O concentrations (DRN2) along the length of the denitrification bed was 6.7 ± 1.61 g N m⁻³ d⁻¹. Lastly, denitrification rates calculated from changes in natural abundance measurements of δ¹⁵N-N₂ and δ¹⁵N- NO₃⁻ along the length of the bed yielded a denitrification rate (DRNA) of 6.39 ± 2.07 g m⁻³ d⁻¹. Based on our experience, DRN2 measurements were the easiest and most efficient approach for determining the denitrification rate and N₂O production of a denitrification bed. However, the other approaches were useful for testing other hypotheses such as factors limiting denitrification or may be applied to determine denitrification rates in environmental systems different to our study site. DRN2 does require very careful sampling to avoid atmospheric N2 contamination but could be used to rapidly determine denitrification rates in a variety of aquatic systems with high N2 production and even water flows. These measurements demonstrated that the majority of NO₃⁻ removal was due to heterotrophic denitrification.

text: A comparison of different approaches for measuring denitrification rates in a nitrate removing bioreactor Denitrifying woodchip bioreactors (denitrification beds) are increasingly used to remove excess nitrate (NO₃⁻) from point-sources such as wastewater effluent or subsurface drains from agricultural fields. NO₃⁻ removal in these beds is assumed to be due to microbial denitrification but direct measurements of denitrification are lacking. Our objective was to test four different approaches for measuring denitrification rates in a denitrification bed that treated effluent discharged from a glasshouse. We compared these denitrification rates with the rate of NO₃⁻ removal along the length of the bed. The NO₃⁻ removal rate was 8.73 ± 1.45 g m⁻³ d⁻¹. In vitro acetylene inhibition assays resulted in highly variable denitrification rates (DRAI) along the length of the bed and generally 5 times greater than the measured (NO₃⁻- N removal rate. An in situ push–pull test, where enriched ¹⁵N- NO₃⁻was injected into 2 locations along the bed, resulted in rates of 23.2 ± 1.43 g N m⁻³ d⁻¹ and 8.06 ± 1.64 g N m⁻³ d⁻¹. The denitrification rate calculated from the increase in dissolved N2 and N2O concentrations (DRN2) along the length of the denitrification bed was 6.7 ± 1.61 g N m⁻³ d⁻¹. Lastly, denitrification rates calculated from changes in natural abundance measurements of δ¹⁵N-N₂ and δ¹⁵N- NO₃⁻ along the length of the bed yielded a denitrification rate (DRNA) of 6.39 ± 2.07 g m⁻³ d⁻¹. Based on our experience, DRN2 measurements were the easiest and most efficient approach for determining the denitrification rate and N₂O production of a denitrification bed. However, the other approaches were useful for testing other hypotheses such as factors limiting denitrification or may be applied to determine denitrification rates in environmental systems different to our study site. DRN2 does require very careful sampling to avoid atmospheric N2 contamination but could be used to rapidly determine denitrification rates in a variety of aquatic systems with high N2 production and even water flows. These measurements demonstrated that the majority of NO₃⁻ removal was due to heterotrophic denitrification.

year: 2011

title: Developing a recovery ethos for psychiatric  services in New Zealand

authors: Smith, Mark Andrew

subjects: Philosophy

abstract: This thesis is about developing a recovery ethos for psychiatric services in New Zealand. The argument of the thesis is that  currently a procedural ethos is dominant in psychiatric services in New Zealand, based on eclectic ways of facilitating recovery. Recovery from mental illness, is based on the criteria of symptom reduction and functioning and can be further refined to   have a client and professional perspective. Rather than using an eclectic approach to facilitating recovery the thesis argues for a pluralistic approach, where the virtues, the relationship with professionals, client narrative and the psychiatric community become central to decision making, rather than principle based procedures.
  The thesis is an argued, applied philosophical thesis in terms of methodology. The scope of the thesis is psychiatric services and the focus is broadly ethical decision making. There are three main divisions to the thesis. Part 1 is concerned with clarification of the main terms used in the thesis. This involves exploring the  historical background to the concept of recovery, clarifying the concept of recovery itself and providing an argument for giving greater prominence to the term mental illness over the term mental disorder. Part 2  identifies the main problem of the thesis, namely the procedural ethos, and the problems it is causing clients suffering from mental illness in facilitating their recovery. Part 3  shows what is involved in developing a recovery ethos for psychiatric services in New Zealand.

text: Developing a recovery ethos for psychiatric  services in New Zealand This thesis is about developing a recovery ethos for psychiatric services in New Zealand. The argument of the thesis is that  currently a procedural ethos is dominant in psychiatric services in New Zealand, based on eclectic ways of facilitating recovery. Recovery from mental illness, is based on the criteria of symptom reduction and functioning and can be further refined to   have a client and professional perspective. Rather than using an eclectic approach to facilitating recovery the thesis argues for a pluralistic approach, where the virtues, the relationship with professionals, client narrative and the psychiatric community become central to decision making, rather than principle based procedures.
  The thesis is an argued, applied philosophical thesis in terms of methodology. The scope of the thesis is psychiatric services and the focus is broadly ethical decision making. There are three main divisions to the thesis. Part 1 is concerned with clarification of the main terms used in the thesis. This involves exploring the  historical background to the concept of recovery, clarifying the concept of recovery itself and providing an argument for giving greater prominence to the term mental illness over the term mental disorder. Part 2  identifies the main problem of the thesis, namely the procedural ethos, and the problems it is causing clients suffering from mental illness in facilitating their recovery. Part 3  shows what is involved in developing a recovery ethos for psychiatric services in New Zealand.

year: 2007

title: Outcomes in different ethnic groups of New Zealand patients with screen-detected vs. non-screen-detected breast cancer.

authors: Lawrenson, Ross

subjects: Breast screening

abstract: OBJECTIVE: To compare characteristics and survival of New Zealand European, Māori, and Pacific women with screen-detected vs. non-screen-detected breast cancer. 
METHODS: Women aged 45-69 diagnosed with invasive breast cancer between January 2005 and May 2013 were identified from the Waikato and Auckland Breast Cancer Registries. Patient demographics and tumour characteristics were described by detection mode and ethnicity. Kaplan-Meier method was used to estimate the five-year breast cancer-specific survival of women with stage I-III breast cancer by ethnicity and detection mode. 
RESULTS: Women with screen-detected cancers were older, had smaller tumours, fewer stage IV (0.8% vs. 7.6%), fewer high grade (16.8% vs. 39.0%), and fewer lymph node positive diseases (26.3% vs. 51.5%) than women with non-screen-detected cancers. There were more Luminal A (70.0% vs. 54.0%), fewer human epidermal growth factor receptor 2 positive non-Luminal (4.4% vs. 8.8%), and fewer triple negative cases (7.0% vs. 13.8%) in screen-detected than non-screen-detected cancers. If not screen detected, 22.7% of breast cancers in Pacific women were stage IV compared with 2.4% if screen detected. If not screen detected, the five-year breast cancer-specific survival was 91.1% for New Zealand European women, 84.2% for Māori women, and 80.2% for Pacific women (p-value <0.001). For screen-detected breast cancer, survival between different ethnic groups was similar.
CONCLUSIONS: Breast cancers detected through screening are diagnosed at an earlier stage and have a greater proportion of subtypes, with better outcome. Variations in survival for Māori and Pacific women are only found in women with non-screen-detected breast cancer.

text: Outcomes in different ethnic groups of New Zealand patients with screen-detected vs. non-screen-detected breast cancer. OBJECTIVE: To compare characteristics and survival of New Zealand European, Māori, and Pacific women with screen-detected vs. non-screen-detected breast cancer. 
METHODS: Women aged 45-69 diagnosed with invasive breast cancer between January 2005 and May 2013 were identified from the Waikato and Auckland Breast Cancer Registries. Patient demographics and tumour characteristics were described by detection mode and ethnicity. Kaplan-Meier method was used to estimate the five-year breast cancer-specific survival of women with stage I-III breast cancer by ethnicity and detection mode. 
RESULTS: Women with screen-detected cancers were older, had smaller tumours, fewer stage IV (0.8% vs. 7.6%), fewer high grade (16.8% vs. 39.0%), and fewer lymph node positive diseases (26.3% vs. 51.5%) than women with non-screen-detected cancers. There were more Luminal A (70.0% vs. 54.0%), fewer human epidermal growth factor receptor 2 positive non-Luminal (4.4% vs. 8.8%), and fewer triple negative cases (7.0% vs. 13.8%) in screen-detected than non-screen-detected cancers. If not screen detected, 22.7% of breast cancers in Pacific women were stage IV compared with 2.4% if screen detected. If not screen detected, the five-year breast cancer-specific survival was 91.1% for New Zealand European women, 84.2% for Māori women, and 80.2% for Pacific women (p-value <0.001). For screen-detected breast cancer, survival between different ethnic groups was similar.
CONCLUSIONS: Breast cancers detected through screening are diagnosed at an earlier stage and have a greater proportion of subtypes, with better outcome. Variations in survival for Māori and Pacific women are only found in women with non-screen-detected breast cancer.

year: 2019