title: Conifer-angiosperm interactions: Physiological ecology and life history.

authors: Lusk, Christopher H.

abstract: Worldwide, conifers are most successful on sites subject to chronic stresses that limit productivity (low temperatures, nutrient poverty, poor drainage). They are poorly represented in the lowland tropics but are often important in Montane tropical forests. Here I explore some functional differences between leaf and xylem traits of conifer and angiosperm trees and their implications for the distributions of these two groups on environmental gradients. Analysis of a global data set shows that compared with angiosperm trees, conifers tend to have longer-lived leaves with greater mass per area (LMA) and lower mass-based photosynthetic capacity. As leaf life span is thought to be the main determinant of nutrient retention time, the prominence of conifers on infertile soils worldwide is at least partly attributable to thrifty use of nutrients through long leaf life spans. Furthermore, because leaf life span correlates with litter decomposition rates, these leaf trait differences could potentially influence the competitive balance between conifers and angiosperms via positive feedbacks on nutrient cycling. Although scaling of leaf life span with LMA is similar in the two groups, angiosperms achieve slightly longer leaf life spans than conifers of similar photosynthetic capacity. This might be caused by less-efficient leaf display in conifers, resulting in the useful life span of leaves being curtailed by self-shading. Representatives of both lineages have narrower conduits in the temperate zone than in the lowland tropics/subtropics, reflecting selection for resistance to freeze-thaw embolism in cold climates. However, conduit diameters of conifers and angiosperm trees differ more in tropical and subtropical forests than at higher latitudes. This probably reflects mechanical constraints on maximum tracheid diameters in the homoxylous wood of conifers, preventing this group from producing the highly conductive wood typical of fast-growing angiosperm pioneers in tropical forests. This pattern might explain why coexistence of conifers and angiosperms is more common in temperate forests and on tropical mountains than in the lowland tropics. Impairment of angiosperm carbon gain by freeze-thaw embolism during cold weather may further narrow performance differences between the two lineages on temperate sites. Differences in canopy residence time probably deserve more attention as a determinant of conifer-angiosperm coexistence in many temperate forests, the longer life span of conifers compensating for infrequent recruitment.

text: Conifer-angiosperm interactions: Physiological ecology and life history. Worldwide, conifers are most successful on sites subject to chronic stresses that limit productivity (low temperatures, nutrient poverty, poor drainage). They are poorly represented in the lowland tropics but are often important in Montane tropical forests. Here I explore some functional differences between leaf and xylem traits of conifer and angiosperm trees and their implications for the distributions of these two groups on environmental gradients. Analysis of a global data set shows that compared with angiosperm trees, conifers tend to have longer-lived leaves with greater mass per area (LMA) and lower mass-based photosynthetic capacity. As leaf life span is thought to be the main determinant of nutrient retention time, the prominence of conifers on infertile soils worldwide is at least partly attributable to thrifty use of nutrients through long leaf life spans. Furthermore, because leaf life span correlates with litter decomposition rates, these leaf trait differences could potentially influence the competitive balance between conifers and angiosperms via positive feedbacks on nutrient cycling. Although scaling of leaf life span with LMA is similar in the two groups, angiosperms achieve slightly longer leaf life spans than conifers of similar photosynthetic capacity. This might be caused by less-efficient leaf display in conifers, resulting in the useful life span of leaves being curtailed by self-shading. Representatives of both lineages have narrower conduits in the temperate zone than in the lowland tropics/subtropics, reflecting selection for resistance to freeze-thaw embolism in cold climates. However, conduit diameters of conifers and angiosperm trees differ more in tropical and subtropical forests than at higher latitudes. This probably reflects mechanical constraints on maximum tracheid diameters in the homoxylous wood of conifers, preventing this group from producing the highly conductive wood typical of fast-growing angiosperm pioneers in tropical forests. This pattern might explain why coexistence of conifers and angiosperms is more common in temperate forests and on tropical mountains than in the lowland tropics. Impairment of angiosperm carbon gain by freeze-thaw embolism during cold weather may further narrow performance differences between the two lineages on temperate sites. Differences in canopy residence time probably deserve more attention as a determinant of conifer-angiosperm coexistence in many temperate forests, the longer life span of conifers compensating for infrequent recruitment.

year: 2011

title: Compositional synthesis of discrete event systems using synthesis abstraction

authors: Mohajerani, Sahar

subjects: computer science

abstract: This paper proposes a general method to synthesize a least restrictive supervisor for a large discrete event system model, consisting of a large number of arbitrary automata representing the plants and specifications. A new type of abstraction called synthesis abstraction is introduced and three rules are proposed to calculate an abstraction of a given automaton. Furthermore, a compositional algorithm for synthesizing a supervisor for large-scale systems of composed finite-state automata is proposed. In the proposed algorithm, the synchronous composition is computed step by step and intermediate results are simplified according to synthesis abstraction. Then a supervisor for the abstracted system is calculated, which in combination with the original system gives the least restrictive, nonblocking, and controllable behaviour.

text: Compositional synthesis of discrete event systems using synthesis abstraction This paper proposes a general method to synthesize a least restrictive supervisor for a large discrete event system model, consisting of a large number of arbitrary automata representing the plants and specifications. A new type of abstraction called synthesis abstraction is introduced and three rules are proposed to calculate an abstraction of a given automaton. Furthermore, a compositional algorithm for synthesizing a supervisor for large-scale systems of composed finite-state automata is proposed. In the proposed algorithm, the synchronous composition is computed step by step and intermediate results are simplified according to synthesis abstraction. Then a supervisor for the abstracted system is calculated, which in combination with the original system gives the least restrictive, nonblocking, and controllable behaviour.

year: 2011

title: Kaumatua Mana Motuhake: peer education intervention to help Maori elders during later-stage life transitions

authors: Oetzel, John G.

subjects: Science & Technology

abstract: Background
Aotearoa/New Zealand has a population that is ageing and there are challenges to health and social outcomes related to related to key life transitions (e.g., retirement, change in health conditions, loss of spouse). Further, there are significant inequities between Māori (Indigenous people) and non-Māori in ageing outcomes. The purpose of this study was to test the impacts and cost effectiveness of a tuakana/teina (peer education) intervention on kaumātua (elders) receiving the intervention. This study was framed by a strengths-based approach based on the key cultural concept of mana motuhake (autonomy and self-actualisation).

Methods
This study was grounded in principles of Kaupapa Māori and community-based participatory research to bring together a diverse group of stakeholders to co-develop and co-evaluate the intervention. The intervention had tuakana (peer educators) having conversations with up to six teina (recipients) and providing information related to health and social services. The research design was a pre- and post-test, clustered staggered design. Participants completed a baseline assessment of health and mana motuhake measures consistent with Māori worldviews along with two follow-up assessments (one after the first intervention group completed its activities and a second after the second intervention group completed its activities). Additionally, five focus groups and open-ended questions on the assessments were used to provide qualitative evaluation.

Findings
A total of 180 kaumātua were recruited to the intervention with 121 completing it. The analysis revealed improvements over time in the expected direction on most of the variables. However, only three of the variables had statistically significant intervention effects: received support, tribal identity, and trouble paying bills. Qualitative results supported impacts of the intervention on mana motuhake, social connectedness, and tangible/information support related to services. Cost-effectiveness analysis showed that the intervention is cost effective, with a cost per QALY of less than the conventional threshold of three times gross domestic product per capita.

Conclusions
The findings support the relevancy and importance of kaumātua knowledge to create a strengths-based approach to improve health and social outcomes. This study demonstrates that a contextually based and culturally safe age-friendly environments can facilitate engagement and participation by kaumātua for kaumātua.

Trial registry
Australia New Zealand Clinical Trial Registry (ACTRN12617001396314); Date Registered: 3 October 2017 (retrospectively registered); https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373733&isClinicalTrial=False

text: Kaumatua Mana Motuhake: peer education intervention to help Maori elders during later-stage life transitions Background
Aotearoa/New Zealand has a population that is ageing and there are challenges to health and social outcomes related to related to key life transitions (e.g., retirement, change in health conditions, loss of spouse). Further, there are significant inequities between Māori (Indigenous people) and non-Māori in ageing outcomes. The purpose of this study was to test the impacts and cost effectiveness of a tuakana/teina (peer education) intervention on kaumātua (elders) receiving the intervention. This study was framed by a strengths-based approach based on the key cultural concept of mana motuhake (autonomy and self-actualisation).

Methods
This study was grounded in principles of Kaupapa Māori and community-based participatory research to bring together a diverse group of stakeholders to co-develop and co-evaluate the intervention. The intervention had tuakana (peer educators) having conversations with up to six teina (recipients) and providing information related to health and social services. The research design was a pre- and post-test, clustered staggered design. Participants completed a baseline assessment of health and mana motuhake measures consistent with Māori worldviews along with two follow-up assessments (one after the first intervention group completed its activities and a second after the second intervention group completed its activities). Additionally, five focus groups and open-ended questions on the assessments were used to provide qualitative evaluation.

Findings
A total of 180 kaumātua were recruited to the intervention with 121 completing it. The analysis revealed improvements over time in the expected direction on most of the variables. However, only three of the variables had statistically significant intervention effects: received support, tribal identity, and trouble paying bills. Qualitative results supported impacts of the intervention on mana motuhake, social connectedness, and tangible/information support related to services. Cost-effectiveness analysis showed that the intervention is cost effective, with a cost per QALY of less than the conventional threshold of three times gross domestic product per capita.

Conclusions
The findings support the relevancy and importance of kaumātua knowledge to create a strengths-based approach to improve health and social outcomes. This study demonstrates that a contextually based and culturally safe age-friendly environments can facilitate engagement and participation by kaumātua for kaumātua.

Trial registry
Australia New Zealand Clinical Trial Registry (ACTRN12617001396314); Date Registered: 3 October 2017 (retrospectively registered); https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373733&isClinicalTrial=False

year: 2020