title: Machine Learning for PAC1D and SESE

authors: Kurz, Jason A.

abstract: This document outlines various machine learning approaches that were taken in an effort to surrogate numerical models Python Ablation Code 1-Dimension (PAC1D) and Scalable Effects Simulation Environment (SESE), with the ultimate objective of discovering the most efficient method for approximating SESE with sparse data utilization. The methods explored include; physics-informed neural networks, deep Galerkin method, deep mixed residual methods, operator network, deep operator network, Fourier neural operator, physics-informed Fourier neural operator, and physics-informed kernel neural operator. Many of the methods showed strengths and weaknesses in their performance, with the physics-informed kernel neural operator showing the most potential for approximating SESE’s behavior.

text: Machine Learning for PAC1D and SESE This document outlines various machine learning approaches that were taken in an effort to surrogate numerical models Python Ablation Code 1-Dimension (PAC1D) and Scalable Effects Simulation Environment (SESE), with the ultimate objective of discovering the most efficient method for approximating SESE with sparse data utilization. The methods explored include; physics-informed neural networks, deep Galerkin method, deep mixed residual methods, operator network, deep operator network, Fourier neural operator, physics-informed Fourier neural operator, and physics-informed kernel neural operator. Many of the methods showed strengths and weaknesses in their performance, with the physics-informed kernel neural operator showing the most potential for approximating SESE’s behavior.

year: 2023-04-03

title: Trends in soil carbon and nutrients of hill-country pastures receiving different phosphorus fertilizer loadings for 20 years

authors: Schipper, Louis A.

subjects: soil carbon

abstract: There are few records of long-term trends in soil C and N in grazed pasture systems but recent measurements have demonstrated unexplained losses on New Zealand lowlands. To determine whether losses were also occurring in hill country pastures, we analyzed archived soil samples collected between 1983 and 2006 from two slope classes (steep and easy) at the Whatawhata Research Centre. Soils were Ultic Hapludand and Typic Haplohumult on the easy slopes (10–20°), and Typic Haplohumult on the steeper slopes (30–40°). Soil samples (0–75 mm) had been collected from paddocks that were fertilized with six different loading rates of P (ranging from 0 to 100 kg P ha⁻¹ year⁻¹ since 1985). This range of P loadings allowed us to determine whether P inputs would regulate trends in soil C and N. While there were significant temporal trends in C and N (P < 0.05), these were not unidirectional and trends were not dependent on P loading rate. On average, soil C initially increased during the first 6 years of the trial at 0.270% C year⁻¹ (1.56 t ha⁻¹ year⁻¹) and 0.156% C year⁻¹ (1.06 t ha⁻¹ year⁻¹) on easy and steep slopes, respectively. Subsequently, there was no significant trend in soil C on the easy slopes but soil C declined at −0.066% year⁻¹ (0.45 t ha⁻¹ year⁻¹) on the steep slopes. Similarly, soil N increased between 1983 and 1989 at 0.025% N year⁻¹ (144 kg ha⁻¹ year⁻¹) and 0.012% N year⁻¹ (82 kg ha⁻¹ year⁻¹) on easy and steep slopes, respectively. Post-1989, small but significant losses of total N were measured on the steep slopes of 0.004% year⁻¹ (27 kg N ha⁻¹ year⁻¹) (P < 0.05) with no trend on the easy slopes. Two potential causal factors for these decadal-scale patterns were identified, operating via changes in primary productivity. These were lower S inputs from 1989 due to a change in fertilizer type, and a series of relatively dry summers during the 1990s. These significant inter-annual trends in soil C and N complicate attempts to measure long-term changes in soil organic matter associated with land use change and management practices. This study has demonstrated the potential error associated with infrequent soil sampling to determine long-term trends in soil C and N; large gains or losses could have been detected at Whatawhata depending on when sampling started and finished. Understanding these long-term trends in soil organic matter dynamics and driving factors requires more long-term sampling trials.

text: Trends in soil carbon and nutrients of hill-country pastures receiving different phosphorus fertilizer loadings for 20 years There are few records of long-term trends in soil C and N in grazed pasture systems but recent measurements have demonstrated unexplained losses on New Zealand lowlands. To determine whether losses were also occurring in hill country pastures, we analyzed archived soil samples collected between 1983 and 2006 from two slope classes (steep and easy) at the Whatawhata Research Centre. Soils were Ultic Hapludand and Typic Haplohumult on the easy slopes (10–20°), and Typic Haplohumult on the steeper slopes (30–40°). Soil samples (0–75 mm) had been collected from paddocks that were fertilized with six different loading rates of P (ranging from 0 to 100 kg P ha⁻¹ year⁻¹ since 1985). This range of P loadings allowed us to determine whether P inputs would regulate trends in soil C and N. While there were significant temporal trends in C and N (P < 0.05), these were not unidirectional and trends were not dependent on P loading rate. On average, soil C initially increased during the first 6 years of the trial at 0.270% C year⁻¹ (1.56 t ha⁻¹ year⁻¹) and 0.156% C year⁻¹ (1.06 t ha⁻¹ year⁻¹) on easy and steep slopes, respectively. Subsequently, there was no significant trend in soil C on the easy slopes but soil C declined at −0.066% year⁻¹ (0.45 t ha⁻¹ year⁻¹) on the steep slopes. Similarly, soil N increased between 1983 and 1989 at 0.025% N year⁻¹ (144 kg ha⁻¹ year⁻¹) and 0.012% N year⁻¹ (82 kg ha⁻¹ year⁻¹) on easy and steep slopes, respectively. Post-1989, small but significant losses of total N were measured on the steep slopes of 0.004% year⁻¹ (27 kg N ha⁻¹ year⁻¹) (P < 0.05) with no trend on the easy slopes. Two potential causal factors for these decadal-scale patterns were identified, operating via changes in primary productivity. These were lower S inputs from 1989 due to a change in fertilizer type, and a series of relatively dry summers during the 1990s. These significant inter-annual trends in soil C and N complicate attempts to measure long-term changes in soil organic matter associated with land use change and management practices. This study has demonstrated the potential error associated with infrequent soil sampling to determine long-term trends in soil C and N; large gains or losses could have been detected at Whatawhata depending on when sampling started and finished. Understanding these long-term trends in soil organic matter dynamics and driving factors requires more long-term sampling trials.

year: 2010

title: Systemic racism and oppression in psychology: Voices from psychologists, academic staff, and students

authors: Waitoki, Waikaremoana

subjects: psychology

abstract: Psychology must reassess its training approach, as the current monocultural paradigm not only causes harm, but also fails to equip psychologists with the knowledge needed to provide culturally appropriate care for Māori, Pacific, Asian, and other minoritised groups. Findings from this report contribute to the growing evidence of the urgent need to address barriers preventing Māori, Pacific, Asian, and other minoritised groups from participating effectively in professional psychology programmes. This 
report calls for action for everyone in psychology to embrace the changes needed to improve the cultural safety of the discipline and hold ourselves accountable for supporting the development of Te Tiriti-aligned psychology.

text: Systemic racism and oppression in psychology: Voices from psychologists, academic staff, and students Psychology must reassess its training approach, as the current monocultural paradigm not only causes harm, but also fails to equip psychologists with the knowledge needed to provide culturally appropriate care for Māori, Pacific, Asian, and other minoritised groups. Findings from this report contribute to the growing evidence of the urgent need to address barriers preventing Māori, Pacific, Asian, and other minoritised groups from participating effectively in professional psychology programmes. This 
report calls for action for everyone in psychology to embrace the changes needed to improve the cultural safety of the discipline and hold ourselves accountable for supporting the development of Te Tiriti-aligned psychology.

year: 2024