title: Wave dissipation by flexible vegetation

authors: Riffe, Kassi C.

subjects: wave

abstract: Dissipation of waves propagating through natural salt marsh vegetation was about half the dissipation expected for rigid vegetation. This low dissipation was predicted by a theoretical model that accounts for bending of vegetation by wave motions. A transect of 3 pulse-coherent Acoustic Doppler Current Profilers recorded water velocity and pressure (at 8 Hz) within the dense (650 stems/m²) canopy of semi-flexible single-stem vegetation (Schoenoplectus americanus). Most wave energy (56 - 81%) was dissipated within 19 m of the marsh edge. Two dissipation models, the first assuming rigid vegetation, and the second simulating wave-forced vegetation motion using the theory for bending of linearly-elastic beams, were tested. After choosing optimal drag coefficients, both models yielded a good fit to the observed dissipation (skill score = 0.95 - 0.99). However, fitted drag coefficients for the rigid model (0.58 - 0.78) were below the range (0.98 - 2.2) expected for the observed Reynolds numbers (13 - 450) and canopy densities (accounting for interactions between stem wakes), whereas drag coefficients for the flexible model (0.97 - 1.6) were nearer the expected range, indicating that prediction of wave dissipation was improved by simulating vegetation motion.

text: Wave dissipation by flexible vegetation Dissipation of waves propagating through natural salt marsh vegetation was about half the dissipation expected for rigid vegetation. This low dissipation was predicted by a theoretical model that accounts for bending of vegetation by wave motions. A transect of 3 pulse-coherent Acoustic Doppler Current Profilers recorded water velocity and pressure (at 8 Hz) within the dense (650 stems/m²) canopy of semi-flexible single-stem vegetation (Schoenoplectus americanus). Most wave energy (56 - 81%) was dissipated within 19 m of the marsh edge. Two dissipation models, the first assuming rigid vegetation, and the second simulating wave-forced vegetation motion using the theory for bending of linearly-elastic beams, were tested. After choosing optimal drag coefficients, both models yielded a good fit to the observed dissipation (skill score = 0.95 - 0.99). However, fitted drag coefficients for the rigid model (0.58 - 0.78) were below the range (0.98 - 2.2) expected for the observed Reynolds numbers (13 - 450) and canopy densities (accounting for interactions between stem wakes), whereas drag coefficients for the flexible model (0.97 - 1.6) were nearer the expected range, indicating that prediction of wave dissipation was improved by simulating vegetation motion.

year: 2011

title: Behavioural Endocrinology of Breeding Adelie Penguins (Pygoscelis adeliae)

authors: Ninnes, Calum Edward

subjects: Adelie penguin

abstract: Measuring hormonal changes is vital for understanding how the social and physical environment influences behaviour, reproduction and survival. Various methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross validated to ensure they correlate. I directly compare faecal and plasma hormone measurements (Chapter 2), and use the most suitable endocrine measure to test the Darling hypothesis (Chapter 3) - that breeding is hastened and synchronized in larger colonies due to increased social stimulation (mediated by the endocrine system).
Blood and faecal samples were simultaneously collected from individual Adelie penguins (Pygoscelis adeliae) for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher corticosterone levels than females, but the difference was only significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males; perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Faecal sampling appears more suitable for assessing baseline hormone levels.
In the second study I examined, over two seasons, whether the timing of breeding varied with colony size; larger colonies present occupants with higher levels of social stimulation and are predicted to show earlier, more synchronous breeding. Baseline faecal hormone levels throughout the breeding season, and survival, were measured to investigate possible proximate and ultimate mechanisms for the results. The influence of environmental variability was examined, by relating the timing of breeding, survival, and endocrine changes to sea ice conditions. Colony size did not influence the timing or synchrony of breeding, survival, or hormone levels within years; perhaps because colonies in an Adelie rookery are not independent from the 'social environment' of adjacent colonies. Across years, synchrony in the smaller rookery was higher than in the larger rookery. The scale of these comparisons may exceed the applicability of the Darling hypothesis. Therefore, no support was found for the Darling hypothesis, at the colony or rookery level, in this species. Higher corticosterone metabolite and lower sex hormone levels in the first season correlated to later breeding and lower survival compared to the second season. This is likely due to the persistence of extensive sea ice conditions late into the first season.
Researchers should take care in selecting the most appropriate method of hormone measurement for their question. Future studies testing the Darling hypothesis must carefully select their definition of a colony (i.e. a truly isolated social unit) and the scale at which the hypothesis is tested. Combining endocrine measurements with behavioural, survival, and environmental information allows for a more comprehensive interpretation of animal ecology.

text: Behavioural Endocrinology of Breeding Adelie Penguins (Pygoscelis adeliae) Measuring hormonal changes is vital for understanding how the social and physical environment influences behaviour, reproduction and survival. Various methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross validated to ensure they correlate. I directly compare faecal and plasma hormone measurements (Chapter 2), and use the most suitable endocrine measure to test the Darling hypothesis (Chapter 3) - that breeding is hastened and synchronized in larger colonies due to increased social stimulation (mediated by the endocrine system).
Blood and faecal samples were simultaneously collected from individual Adelie penguins (Pygoscelis adeliae) for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher corticosterone levels than females, but the difference was only significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males; perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Faecal sampling appears more suitable for assessing baseline hormone levels.
In the second study I examined, over two seasons, whether the timing of breeding varied with colony size; larger colonies present occupants with higher levels of social stimulation and are predicted to show earlier, more synchronous breeding. Baseline faecal hormone levels throughout the breeding season, and survival, were measured to investigate possible proximate and ultimate mechanisms for the results. The influence of environmental variability was examined, by relating the timing of breeding, survival, and endocrine changes to sea ice conditions. Colony size did not influence the timing or synchrony of breeding, survival, or hormone levels within years; perhaps because colonies in an Adelie rookery are not independent from the 'social environment' of adjacent colonies. Across years, synchrony in the smaller rookery was higher than in the larger rookery. The scale of these comparisons may exceed the applicability of the Darling hypothesis. Therefore, no support was found for the Darling hypothesis, at the colony or rookery level, in this species. Higher corticosterone metabolite and lower sex hormone levels in the first season correlated to later breeding and lower survival compared to the second season. This is likely due to the persistence of extensive sea ice conditions late into the first season.
Researchers should take care in selecting the most appropriate method of hormone measurement for their question. Future studies testing the Darling hypothesis must carefully select their definition of a colony (i.e. a truly isolated social unit) and the scale at which the hypothesis is tested. Combining endocrine measurements with behavioural, survival, and environmental information allows for a more comprehensive interpretation of animal ecology.

year: 2008

title: An evaluation of Te Rau Puawai workforce 100: Stakeholder perspectives

authors: Nikora, Linda Waimarie

subjects: Maori students

abstract: To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
There are a number of stakeholders who do not have a direct role in the provision of
Te Rau Puawai. These people are not involved in the day to day running of Te Rau
Puawai (as do, for example, the coordinator, support team or academic mentors),
nevertheless they play an important role, contributing in a variety of ways to the
programme.

text: An evaluation of Te Rau Puawai workforce 100: Stakeholder perspectives To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
There are a number of stakeholders who do not have a direct role in the provision of
Te Rau Puawai. These people are not involved in the day to day running of Te Rau
Puawai (as do, for example, the coordinator, support team or academic mentors),
nevertheless they play an important role, contributing in a variety of ways to the
programme.

year: 2002-05-01