title: SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP

authors: Hogg, Alan G.

subjects: carbon cycle

abstract: Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 ¹⁴C yrs older.

text: SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 ¹⁴C yrs older.

year: 2020

title: On the accuracy of simulations of turbulence

authors: Wan, Minping

subjects: turbulence

abstract: The widely recognized issue of adequate spatial resolution in numerical simulations of turbulence is studied in the context of two-dimensional magnetohydrodynamics. The familiar criterion that the dissipation scale should be resolved enables accurate computation of the spectrum, but fails for precise determination of higher-order statistical quantities. Examination of two straightforward diagnostics, the maximum of the kurtosis and the scale-dependent kurtosis, enables the development of simple tests for assessing adequacy of spatial resolution. The efficacy of the tests is confirmed by examining a sample problem, the distribution of magnetic reconnection rates in turbulence. Oversampling the Kolmogorov dissipation scale by a factor of 3 allows accurate computation of the kurtosis, the scale-dependent kurtosis, and the reconnection rates. These tests may provide useful guidance for resolution requirements in many plasma computations involving turbulence and reconnection.

text: On the accuracy of simulations of turbulence The widely recognized issue of adequate spatial resolution in numerical simulations of turbulence is studied in the context of two-dimensional magnetohydrodynamics. The familiar criterion that the dissipation scale should be resolved enables accurate computation of the spectrum, but fails for precise determination of higher-order statistical quantities. Examination of two straightforward diagnostics, the maximum of the kurtosis and the scale-dependent kurtosis, enables the development of simple tests for assessing adequacy of spatial resolution. The efficacy of the tests is confirmed by examining a sample problem, the distribution of magnetic reconnection rates in turbulence. Oversampling the Kolmogorov dissipation scale by a factor of 3 allows accurate computation of the kurtosis, the scale-dependent kurtosis, and the reconnection rates. These tests may provide useful guidance for resolution requirements in many plasma computations involving turbulence and reconnection.

year: 2010

title: Beyond Pākehā paralysis: Exploring the journeys & experiences of Pākehā allyship in psychology

authors: Stolte, Ottilie Emma Elisabeth

abstract: The monocultural foundation of psychology is interwoven with the colonial history of Aotearoa New Zealand. Not all of the mahi of decolonising psychology is the responsibility of Māori. In Aotearoa, there is currently less literature around the development of racial justice allyship and how Pākehā (as the dominant majority) can work towards honouring Te Tiriti o Waitangi. This paper draws on interviews with three Pākehā allies who have taken actions towards greater inclusion of Māori and raising awareness of systemic injustices and racial disparities. The objective of this paper is to document the understandings shared by these ‘reluctant allies’, focusing on the challenges, possibilities, and suggestions for a more culturally relevant psychological education and practice for Aotearoa New Zealand.

text: Beyond Pākehā paralysis: Exploring the journeys & experiences of Pākehā allyship in psychology The monocultural foundation of psychology is interwoven with the colonial history of Aotearoa New Zealand. Not all of the mahi of decolonising psychology is the responsibility of Māori. In Aotearoa, there is currently less literature around the development of racial justice allyship and how Pākehā (as the dominant majority) can work towards honouring Te Tiriti o Waitangi. This paper draws on interviews with three Pākehā allies who have taken actions towards greater inclusion of Māori and raising awareness of systemic injustices and racial disparities. The objective of this paper is to document the understandings shared by these ‘reluctant allies’, focusing on the challenges, possibilities, and suggestions for a more culturally relevant psychological education and practice for Aotearoa New Zealand.

year: 2025