title: Factors contributing to the unnaturally low water table of Moanatuatua Scientific Reserve, Waikato, New Zealand

authors: Daws, Constance Mary

subjects: peat

abstract: Water table regime in peatlands (depth below the peat surface) is an important driver in biochemical processes. A deep water table can lead to increased rates of peat decomposition resulting in surface subsidence, release of carbon and changes to the vegetation cover. This study focused on the factors responsible for the unnaturally deep and highly fluctuating water table regime at Moanatuatua, a remnant peat bog, in contrast to the hydrologically pristine Kopuatai bog, with a shallow, more stable water table.
Moanatuatua Scientific Reserve in the Hamilton basin is the 1.1 km2 remnant of a former 75 km2 raised peat bog, and Kopuatai bog covers an area of 96 km2 on the Hauraki plains. Native bog vegetation in the Waikato is dominated by two species from the Restionaceae family of vascular plants, Empodisma robustum and Sporadanthus ferrugineus. Water table measurements at Moanatuatua were obtained from nine pressure transducers across an east to west transect of the bog. At Kopuatai, water table measurements were taken from a single reference site. At both bogs evaporation and rainfall were measured by eddy covariance towers. Three years of measurements (1 September 2015 – 31 August 2018) were used to compare the two sites.
The water table at Moanatuatua was consistently very deep for a peat bog and had a strong seasonal cycle resulting in a deeper water table in summer and a shallower water table in winter, with a mean depth of -601 mm below the surface for the three-year study period. Kopuatai also showed a seasonal pattern although the water table did not reach the same extreme depths with a mean water table depth of -25 mm. The water table at Moanatuatua followed the domed shape of the peat surface, but remained well below the peat surface for the duration of the study. The pattern of water table depth across Moanatuatua indicated that the border drains do not cause a drawdown effect on the water table across the entire transect of the bog. Similar water table depths were found 18 years ago suggesting that the hydrological regime at Moanatuatua has not altered much in this time.
Evaporation rates from Moanatuatua were higher than Kopuatai. Mean daily evaporation from Moanatuatua was 2.2 mm and Kopuatai 1.8 mm for the entire study period. Eliminating wet canopy influences the evaporation rate at Moanatuatua was 2.0 mm day-1 and at Kopuatai of 1.45 mm day-1. Mean annual water balance inputs into the bog (rainfall – evaporation) were 587 mm at Moanatuatua and 872 mm at Kopuatai. If the late successional vegetation at Moanatuatua were replaced with early successional vegetation as present at Kopuatai, it is estimated that an average water balance would have been of 741 mm, resulting in more water available for potential water table recharge.

text: Factors contributing to the unnaturally low water table of Moanatuatua Scientific Reserve, Waikato, New Zealand Water table regime in peatlands (depth below the peat surface) is an important driver in biochemical processes. A deep water table can lead to increased rates of peat decomposition resulting in surface subsidence, release of carbon and changes to the vegetation cover. This study focused on the factors responsible for the unnaturally deep and highly fluctuating water table regime at Moanatuatua, a remnant peat bog, in contrast to the hydrologically pristine Kopuatai bog, with a shallow, more stable water table.
Moanatuatua Scientific Reserve in the Hamilton basin is the 1.1 km2 remnant of a former 75 km2 raised peat bog, and Kopuatai bog covers an area of 96 km2 on the Hauraki plains. Native bog vegetation in the Waikato is dominated by two species from the Restionaceae family of vascular plants, Empodisma robustum and Sporadanthus ferrugineus. Water table measurements at Moanatuatua were obtained from nine pressure transducers across an east to west transect of the bog. At Kopuatai, water table measurements were taken from a single reference site. At both bogs evaporation and rainfall were measured by eddy covariance towers. Three years of measurements (1 September 2015 – 31 August 2018) were used to compare the two sites.
The water table at Moanatuatua was consistently very deep for a peat bog and had a strong seasonal cycle resulting in a deeper water table in summer and a shallower water table in winter, with a mean depth of -601 mm below the surface for the three-year study period. Kopuatai also showed a seasonal pattern although the water table did not reach the same extreme depths with a mean water table depth of -25 mm. The water table at Moanatuatua followed the domed shape of the peat surface, but remained well below the peat surface for the duration of the study. The pattern of water table depth across Moanatuatua indicated that the border drains do not cause a drawdown effect on the water table across the entire transect of the bog. Similar water table depths were found 18 years ago suggesting that the hydrological regime at Moanatuatua has not altered much in this time.
Evaporation rates from Moanatuatua were higher than Kopuatai. Mean daily evaporation from Moanatuatua was 2.2 mm and Kopuatai 1.8 mm for the entire study period. Eliminating wet canopy influences the evaporation rate at Moanatuatua was 2.0 mm day-1 and at Kopuatai of 1.45 mm day-1. Mean annual water balance inputs into the bog (rainfall – evaporation) were 587 mm at Moanatuatua and 872 mm at Kopuatai. If the late successional vegetation at Moanatuatua were replaced with early successional vegetation as present at Kopuatai, it is estimated that an average water balance would have been of 741 mm, resulting in more water available for potential water table recharge.

year: 2018

title: General second-rank correlation tensors for homogeneous magnetohydrodynamic turbulence

authors: Oughton, Sean

subjects: turbulence

abstract: The properties and structure of second-order (Cartesian) correlation tensors are derived for the general case of two solenoidal random vector fields. The theory is intended to describe homogeneous magnetohydrodynamic turbulence, with no assumed rotational or reflectional symmetries. Each correlation tensor can be written in terms of four scalar generating functions and the relationship of these functions to the potentials that generate the poloidal and toroidal components of the underlying vector fields is derived. The physical nature of the scalar functions is investigated and their true or pseudoscalar character is ascertained. In our general discussion we clarify several misleading statements dating back to Robertson’s original paper in the field [Proc. Camb. Philos. Soc. 36, 209 (1940)]. It is also shown that using the one-dimensional correlation function, it is possible to obtain spectral information on the induced electric field in directions perpendicular to the measurement direction.

text: General second-rank correlation tensors for homogeneous magnetohydrodynamic turbulence The properties and structure of second-order (Cartesian) correlation tensors are derived for the general case of two solenoidal random vector fields. The theory is intended to describe homogeneous magnetohydrodynamic turbulence, with no assumed rotational or reflectional symmetries. Each correlation tensor can be written in terms of four scalar generating functions and the relationship of these functions to the potentials that generate the poloidal and toroidal components of the underlying vector fields is derived. The physical nature of the scalar functions is investigated and their true or pseudoscalar character is ascertained. In our general discussion we clarify several misleading statements dating back to Robertson’s original paper in the field [Proc. Camb. Philos. Soc. 36, 209 (1940)]. It is also shown that using the one-dimensional correlation function, it is possible to obtain spectral information on the induced electric field in directions perpendicular to the measurement direction.

year: 1997

title: Prevalence of sociodemographic factors in a cohort of diabetes mellitus: A retrospective study

authors: Erandathi, Madurapperumage A.

subjects: complications of diabetes

abstract: Exploring the sociodemographic factors of a cohort is a vital phase in revealing significant aspects of the societal health status. The health care sector utilises the results of exploratory analysis of the sociodemographic nature to fulfil various purposes such as constructing health care policies, allocating adequate resources, imposing necessary medications and many more. A large and growing body of evidence shows that understanding the pervasiveness of sociodemographic factors: age, ethnicity, gender, reveal crucial information. Therefore, this study aims to disclose the knowledge through analysing the sociodemographic details of a New Zealand diabetes cohort. Diabetes mellitus is a chronic fatal disease that occurs due to the inability to control proper blood sugar levels, which causes multitudinous acute and chronic complications. Diabetes became a high prevalence disease in the region of Waikato. Analysing the cohort of diabetes patients associated with complications of diabetes illustrate the prevalence of complications of diabetes among the patients. The dataset of the study has been collected from the Waikato district health board. This study intends to report the initial scanning of the dataset profile with visualising the resulting patterns of sociodemographic details from the samples and their association with complications of diabetes. The Sankey diagrams use to visualise the results of exploratory data analysis. The resulted graphs of the data screening descriptively illustrate the characteristics of the cohort associated with demographic factors. Maori population shows higher percentage (0.68) of diabetes patients than the other ethnicities, while having narrower age expansion (13-95) with early onset age, compared to others (20-103). Males (0.61%) are more vulnerable to diabetes than females (0.55%). Additionally, hypertension and cardiovascular diseases are common among the diabetes patients’ in the Waikato region. Maori male population is highly vulnerable to diabetes. This study will be beneficial in constructing and analysing the demographical categories of the cohort to comparatively study the pervasiveness of the diseases among resulting classes.

text: Prevalence of sociodemographic factors in a cohort of diabetes mellitus: A retrospective study Exploring the sociodemographic factors of a cohort is a vital phase in revealing significant aspects of the societal health status. The health care sector utilises the results of exploratory analysis of the sociodemographic nature to fulfil various purposes such as constructing health care policies, allocating adequate resources, imposing necessary medications and many more. A large and growing body of evidence shows that understanding the pervasiveness of sociodemographic factors: age, ethnicity, gender, reveal crucial information. Therefore, this study aims to disclose the knowledge through analysing the sociodemographic details of a New Zealand diabetes cohort. Diabetes mellitus is a chronic fatal disease that occurs due to the inability to control proper blood sugar levels, which causes multitudinous acute and chronic complications. Diabetes became a high prevalence disease in the region of Waikato. Analysing the cohort of diabetes patients associated with complications of diabetes illustrate the prevalence of complications of diabetes among the patients. The dataset of the study has been collected from the Waikato district health board. This study intends to report the initial scanning of the dataset profile with visualising the resulting patterns of sociodemographic details from the samples and their association with complications of diabetes. The Sankey diagrams use to visualise the results of exploratory data analysis. The resulted graphs of the data screening descriptively illustrate the characteristics of the cohort associated with demographic factors. Maori population shows higher percentage (0.68) of diabetes patients than the other ethnicities, while having narrower age expansion (13-95) with early onset age, compared to others (20-103). Males (0.61%) are more vulnerable to diabetes than females (0.55%). Additionally, hypertension and cardiovascular diseases are common among the diabetes patients’ in the Waikato region. Maori male population is highly vulnerable to diabetes. This study will be beneficial in constructing and analysing the demographical categories of the cohort to comparatively study the pervasiveness of the diseases among resulting classes.

year: 2022