title: The effect of altering maintenance diet on demand for reinforcers.

authors: Jackson, Surrey Merryn Kate

subjects: establishing operations

abstract: Six hens’ preferences between whole grain wheat, commercial laying pellets and puffed wheat were assessed using a free-access procedure. Wheat was found to be the preferred food of three hens, pellets were preferred by one, puffed wheat was found to be not preferred by four, and two hens had no preference for any food. The hens were then maintained at 80% ± 10% of their free-feeding body weights by one of the three foods while responding under a progressive ratio schedule in which the response requirement doubled after each reinforcer. A session terminated after a hen had ceased responding for 300 s. All three foods were used as reinforcers and then the maintenance food was changed. Thus all three foods served as reinforcers with each of the three maintenance diets. Response rates, post-reinforcement pauses and demand functions (i.e., the relation between estimated consumption rate and response requirement) under each response requirement were examined. Performance was not affected systematically across hens by diet or reinforcer type. There were no systematic relations between the individual hen’s food preferences and any of the performance measures. The same hens were then maintained at 80% ± 10% of their free-feeding body weight by pellets and responded under fixed ratio schedules with the response requirement doubling each session until a hen received no reinforcers in a session. Sessions terminated after 40 reinforcers or 40 min. Each of the three foods served as the reinforcer for two series of the increasing fixed ratio schedules. The resulting demand functions did not differ over reinforcer type and no relation found between the type of reinforcer and the individual hen’s preferences. Performance (including the shape of the demand functions) was found to be similar under both the progressive and fixed ratio schedules. It is suggested that the provision of post-feed outside of the experimental sessions and the hen’s low body weights could explain why there was no difference in demand between conditions with different maintenance diets and reinforcer types.

text: The effect of altering maintenance diet on demand for reinforcers. Six hens’ preferences between whole grain wheat, commercial laying pellets and puffed wheat were assessed using a free-access procedure. Wheat was found to be the preferred food of three hens, pellets were preferred by one, puffed wheat was found to be not preferred by four, and two hens had no preference for any food. The hens were then maintained at 80% ± 10% of their free-feeding body weights by one of the three foods while responding under a progressive ratio schedule in which the response requirement doubled after each reinforcer. A session terminated after a hen had ceased responding for 300 s. All three foods were used as reinforcers and then the maintenance food was changed. Thus all three foods served as reinforcers with each of the three maintenance diets. Response rates, post-reinforcement pauses and demand functions (i.e., the relation between estimated consumption rate and response requirement) under each response requirement were examined. Performance was not affected systematically across hens by diet or reinforcer type. There were no systematic relations between the individual hen’s food preferences and any of the performance measures. The same hens were then maintained at 80% ± 10% of their free-feeding body weight by pellets and responded under fixed ratio schedules with the response requirement doubling each session until a hen received no reinforcers in a session. Sessions terminated after 40 reinforcers or 40 min. Each of the three foods served as the reinforcer for two series of the increasing fixed ratio schedules. The resulting demand functions did not differ over reinforcer type and no relation found between the type of reinforcer and the individual hen’s preferences. Performance (including the shape of the demand functions) was found to be similar under both the progressive and fixed ratio schedules. It is suggested that the provision of post-feed outside of the experimental sessions and the hen’s low body weights could explain why there was no difference in demand between conditions with different maintenance diets and reinforcer types.

year: 2011

title: Development of a Method for Trace Analysis of Dioctyl Sodium Sulfosuccinate by Liquid Chromatography Mass Spectrometry and its Application to Samples from the MV Rena Incident

authors: Bernstein, Daniel Richard

subjects: Liquid chromatography

abstract: The grounding of the MV Rena off the coast of Tauranga, New Zealand in 2011 prompted the application of Corexit® oil spill dispersants in an attempt to mitigate the impact of the spilled oil to coastal ecosystems. A quantitative method was developed employing sonication assisted extraction from beach sand followed by sample clean up by solid phase extraction and analysis by liquid chromatography tandem mass spectrometry for the analysis of Corexit® component dioctyl sodium sulfosuccinate (DOSS) at trace levels. The chromatographic method included the use of a C8 stationary phase with a gradient elution and quantitation by an internal standard approach based on mass spectrometer instrument response. Validation studies gave recoveries of 72 ± 1.7% with an accuracy of 94%. Calibration curves were shown to have a linear range of 0 – 200 μg.L⁻¹. Application of the method to the available environmental samples showed no presence of DOSS.
An attempt was made to apply the instrumental method to heavy fuel oil (HFO) tar-balls and oiled sand samples. Multiple extraction techniques were trialled including liquid-liquid extraction, sonication assisted extraction and anion exchange chromatography with recovery experiments for each method being carried out. Analysis of the extracts showed that quantitative recovery of DOSS had not been achieved for any of the methods investigated.
The difficulties associated with extracting DOSS from HFO tar-balls and oil sands suggest that the application of DOSS to surface oil slicks results in the preferential partitioning of DOSS into HFO. This has implications with respect to the distribution of DOSS in the environment following application, subsequent environmental monitoring and the degradation of HFO components by microbial communities.

text: Development of a Method for Trace Analysis of Dioctyl Sodium Sulfosuccinate by Liquid Chromatography Mass Spectrometry and its Application to Samples from the MV Rena Incident The grounding of the MV Rena off the coast of Tauranga, New Zealand in 2011 prompted the application of Corexit® oil spill dispersants in an attempt to mitigate the impact of the spilled oil to coastal ecosystems. A quantitative method was developed employing sonication assisted extraction from beach sand followed by sample clean up by solid phase extraction and analysis by liquid chromatography tandem mass spectrometry for the analysis of Corexit® component dioctyl sodium sulfosuccinate (DOSS) at trace levels. The chromatographic method included the use of a C8 stationary phase with a gradient elution and quantitation by an internal standard approach based on mass spectrometer instrument response. Validation studies gave recoveries of 72 ± 1.7% with an accuracy of 94%. Calibration curves were shown to have a linear range of 0 – 200 μg.L⁻¹. Application of the method to the available environmental samples showed no presence of DOSS.
An attempt was made to apply the instrumental method to heavy fuel oil (HFO) tar-balls and oiled sand samples. Multiple extraction techniques were trialled including liquid-liquid extraction, sonication assisted extraction and anion exchange chromatography with recovery experiments for each method being carried out. Analysis of the extracts showed that quantitative recovery of DOSS had not been achieved for any of the methods investigated.
The difficulties associated with extracting DOSS from HFO tar-balls and oil sands suggest that the application of DOSS to surface oil slicks results in the preferential partitioning of DOSS into HFO. This has implications with respect to the distribution of DOSS in the environment following application, subsequent environmental monitoring and the degradation of HFO components by microbial communities.

year: 2015

title: Health equity and wellbeing among older people's caregivers in New Zealand during COVID-19: Protocol for a qualitative study.

authors: Burholt, Vanessa

subjects: Aged

abstract: BACKGROUND: Knowledge of the challenges unpaid caregivers faced providing care to older people during the COVID-19 pandemic is limited. Challenges may be especially pronounced for those experiencing inequitable access to health and social care. This participatory action research study, located in New Zealand, has four main objectives, (i) to understand the challenges and rewards associated with caregiving to older care recipients during the COVID-19 pandemic restrictions; (ii) to map and collate resources developed (or mobilised) by organisations during the pandemic; (iii) to co-produce policy recommendations, identify useful caregiver resources and practices, prioritise unmet needs (challenges); and, (iv) to use project results in knowledge translation, in order to improve caregivers access to resources, and raise the profile and recognition of caregivers contribution to society. METHODS AND ANALYSIS: Māori, Pacific and rural-dwelling caregivers to 30 older care-recipients, and 30 representatives from organisations supporting caregivers in New Zealand will be interviewed. Combining data from the interviews and caregivers letters (from an archive of older people's pandemic experiences), framework analysis will be used to examine the interrelated systems of the human ecological model and the impact on caregiving experiences during the pandemic. Resources that service providers had created or used for caregivers and older people will be collated and categorised. Through co-production with caregivers and community partners we will produce three short films describing caregivers' pandemic experiences; identify a suite of resources for caregivers to use in future events requiring self-isolation, and in everyday life; and generate ideas to address unresolved issues.

text: Health equity and wellbeing among older people's caregivers in New Zealand during COVID-19: Protocol for a qualitative study. BACKGROUND: Knowledge of the challenges unpaid caregivers faced providing care to older people during the COVID-19 pandemic is limited. Challenges may be especially pronounced for those experiencing inequitable access to health and social care. This participatory action research study, located in New Zealand, has four main objectives, (i) to understand the challenges and rewards associated with caregiving to older care recipients during the COVID-19 pandemic restrictions; (ii) to map and collate resources developed (or mobilised) by organisations during the pandemic; (iii) to co-produce policy recommendations, identify useful caregiver resources and practices, prioritise unmet needs (challenges); and, (iv) to use project results in knowledge translation, in order to improve caregivers access to resources, and raise the profile and recognition of caregivers contribution to society. METHODS AND ANALYSIS: Māori, Pacific and rural-dwelling caregivers to 30 older care-recipients, and 30 representatives from organisations supporting caregivers in New Zealand will be interviewed. Combining data from the interviews and caregivers letters (from an archive of older people's pandemic experiences), framework analysis will be used to examine the interrelated systems of the human ecological model and the impact on caregiving experiences during the pandemic. Resources that service providers had created or used for caregivers and older people will be collated and categorised. Through co-production with caregivers and community partners we will produce three short films describing caregivers' pandemic experiences; identify a suite of resources for caregivers to use in future events requiring self-isolation, and in everyday life; and generate ideas to address unresolved issues.

year: 2022