title: Lagrangian relaxation schemes for calculating force-free magnetic fields, and their limitations

authors: Pontin, D.I.

subjects: magnetic fields

abstract: Force-free magnetic fields are important in many astrophysical settings. Determining the properties of such force-free fields—especially smoothness and stability properties—is crucial to understanding many key phenomena in astrophysical plasmas, for example, energy release processes that heat the plasma and lead to dynamic or explosive events. In the present work we discuss a serious limitation on the computation of force-free fields, within the context of a Lagrangian relaxation scheme that conserves magnetic flux and ∇ • B identically. This issue has the potential to invalidate the results produced by numerical force-free field solvers even for cases in which they appear to converge (at fixed grid resolution) to an equilibrium magnetic field. Error estimates are introduced to assess the quality of the calculated equilibrium. We go on to present an algorithm, based on rewriting the curl operation via Stokes' theorem, for calculating the current which holds great promise for improving dramatically the accuracy of the Lagrangian relaxation procedure.

text: Lagrangian relaxation schemes for calculating force-free magnetic fields, and their limitations Force-free magnetic fields are important in many astrophysical settings. Determining the properties of such force-free fields—especially smoothness and stability properties—is crucial to understanding many key phenomena in astrophysical plasmas, for example, energy release processes that heat the plasma and lead to dynamic or explosive events. In the present work we discuss a serious limitation on the computation of force-free fields, within the context of a Lagrangian relaxation scheme that conserves magnetic flux and ∇ • B identically. This issue has the potential to invalidate the results produced by numerical force-free field solvers even for cases in which they appear to converge (at fixed grid resolution) to an equilibrium magnetic field. Error estimates are introduced to assess the quality of the calculated equilibrium. We go on to present an algorithm, based on rewriting the curl operation via Stokes' theorem, for calculating the current which holds great promise for improving dramatically the accuracy of the Lagrangian relaxation procedure.

year: 2009

title: Photosynthetic responses of three common mosses from continental Antarctica

authors: Pannewitz, Stefan

subjects: bryophytes

abstract: Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment.

text: Photosynthetic responses of three common mosses from continental Antarctica Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment.

year: 2005

title: Guidelines for gender affirming healthcare for gender diverse and transgender children, young people and adults in Aotearoa New Zealand

authors: Oliphant, Jeannie

abstract: Internationally and within New Zealand there has been a substantial increase in the demand for gender affirming healthcare over the past decade. The Youth’12 secondary school survey, estimated that approximately 1.2% of adolescents in New Zealand identify as transgender.¹ It is likely that this level of referrals to health services will continue in the foreseeable future. 
This guideline has been developed following the recognition that New Zealand’s previous good practice guide, Gender Reassignment Health Services for Trans People within New Zealand,² which was based heavily on the World Professional Association of Transgender Health, Standards of Care, version 6 (WPATH SOC v6),³ requires updating to be in step with current practice and international guidelines.
Transgender healthcare is a rapidly evolving area of medicine. WPATH is the international body responsible for producing standards of care. WPATH SOC v7,⁴ was published soon after New Zealand’s good practice guide and version 8 is currently in development. This guideline is not intended to replace the WPATH SOC but to present additional guidance for the provision of gender affirming healthcare in Aotearoa, New Zealand. We hope that this guide will be used to support the development of health services providing gender affirming healthcare around the country and provide guidance to District Health Boards (DHBs).
We use Sir Mason Durie’s health framework to inform the kaupapa or approach of these guidelines. WPATH SOC v7 encourages culturally appropriate approaches which are contextually based.⁴ Durie’s model for health promotion development, Te Pae Māhutonga (the Southern Cross), has two guiding principles which correspond to the pointer stars of the constellation, Te Mana Whakahaere and Ngā Manukura.⁵

text: Guidelines for gender affirming healthcare for gender diverse and transgender children, young people and adults in Aotearoa New Zealand Internationally and within New Zealand there has been a substantial increase in the demand for gender affirming healthcare over the past decade. The Youth’12 secondary school survey, estimated that approximately 1.2% of adolescents in New Zealand identify as transgender.¹ It is likely that this level of referrals to health services will continue in the foreseeable future. 
This guideline has been developed following the recognition that New Zealand’s previous good practice guide, Gender Reassignment Health Services for Trans People within New Zealand,² which was based heavily on the World Professional Association of Transgender Health, Standards of Care, version 6 (WPATH SOC v6),³ requires updating to be in step with current practice and international guidelines.
Transgender healthcare is a rapidly evolving area of medicine. WPATH is the international body responsible for producing standards of care. WPATH SOC v7,⁴ was published soon after New Zealand’s good practice guide and version 8 is currently in development. This guideline is not intended to replace the WPATH SOC but to present additional guidance for the provision of gender affirming healthcare in Aotearoa, New Zealand. We hope that this guide will be used to support the development of health services providing gender affirming healthcare around the country and provide guidance to District Health Boards (DHBs).
We use Sir Mason Durie’s health framework to inform the kaupapa or approach of these guidelines. WPATH SOC v7 encourages culturally appropriate approaches which are contextually based.⁴ Durie’s model for health promotion development, Te Pae Māhutonga (the Southern Cross), has two guiding principles which correspond to the pointer stars of the constellation, Te Mana Whakahaere and Ngā Manukura.⁵

year: 2018