title: Pruning decision trees and lists

authors: Frank, Eibe

abstract: Machine learning algorithms are techniques that automatically build models describing the structure at the heart of a set of data. Ideally, such models can be used to predict properties of future data points and people can use them to analyze the domain from which the data originates. 

Decision trees and lists are potentially powerful predictors and embody an explicit representation of the structure in a dataset. Their accuracy and comprehensibility depends on how concisely the learning algorithm can summarize this structure. The final model should not incorporate spurious effects-patterns that are not genuine features of the underlying domain. Given an efficient mechanism for determining when a particular effect is due to chance alone, non-predictive parts of a model can be eliminated or “pruned.” Pruning mechanisms require a sensitive instrument that uses the data to detect whether there is a genuine relationship between the components of a model and the domain. Statistical significance tests are theoretically well-founded tools for doing exactly that. 

This thesis presents pruning algorithms for decision trees and lists that are based on significance tests. We explain why pruning is often necessary to obtain small and accurate models and show that the performance of standard pruning algorithms can be improved by taking the statistical significance of observations into account. We compare the effect of parametric and non-parametric tests, analyze why current pruning algorithms for decision lists often prune too aggressively, and review related work-in particular existing approaches that use significance tests in the context of pruning. The main outcome of this investigation is a set of simple pruning algorithms that should prove useful in practical data mining applications.

text: Pruning decision trees and lists Machine learning algorithms are techniques that automatically build models describing the structure at the heart of a set of data. Ideally, such models can be used to predict properties of future data points and people can use them to analyze the domain from which the data originates. 

Decision trees and lists are potentially powerful predictors and embody an explicit representation of the structure in a dataset. Their accuracy and comprehensibility depends on how concisely the learning algorithm can summarize this structure. The final model should not incorporate spurious effects-patterns that are not genuine features of the underlying domain. Given an efficient mechanism for determining when a particular effect is due to chance alone, non-predictive parts of a model can be eliminated or “pruned.” Pruning mechanisms require a sensitive instrument that uses the data to detect whether there is a genuine relationship between the components of a model and the domain. Statistical significance tests are theoretically well-founded tools for doing exactly that. 

This thesis presents pruning algorithms for decision trees and lists that are based on significance tests. We explain why pruning is often necessary to obtain small and accurate models and show that the performance of standard pruning algorithms can be improved by taking the statistical significance of observations into account. We compare the effect of parametric and non-parametric tests, analyze why current pruning algorithms for decision lists often prune too aggressively, and review related work-in particular existing approaches that use significance tests in the context of pruning. The main outcome of this investigation is a set of simple pruning algorithms that should prove useful in practical data mining applications.

year: 2000

title: Debridement of wounds with honey

authors: Molan, Peter C.

subjects: honey

abstract: Honey has been used as a debriding agent since ancient times. Its debriding properties have been rediscovered in more recent times, with various case reports published in the latter decades of the 20th century describing its effectiveness in cleaning up wounds. More recently its effectiveness has been compared with that of modern debriding agents, and honey has been found to work more rapidly than all except larval therapy. A randomised controlled trial demonstrated significantly better debriding with honey than with hydrogel. Other trials have shown that honey is a good alternative to surgical debridement for the treatment of necrotising fasciitis in the genital region. Seven case series and ten single case studies have also been published in which the effectiveness of honey in debriding wounds was reported. A prophylactic action of honey has also been reported, where in a randomised controlled trials comparing honey with silver sulfadiazine for the treatment of burns there was no eschar formed with honey but there was eschar formed in the cases treated with silver sulfadiazine. A similar finding has been reported in an animal model, where adjacent experimental wounds were kept clean with honey-soaked gauze but formed thick dense scabs where treated with saline-soaked gauze. The mechanism of action of honey is as yet unknown, but appears to be by way of stimulating autolytic debridement. Additional advantages using honey rather than other moist debridement are that its antibacterial action prevents bacterial growth from being encouraged, and its osmolarity prevents maceration of periwound skin.

text: Debridement of wounds with honey Honey has been used as a debriding agent since ancient times. Its debriding properties have been rediscovered in more recent times, with various case reports published in the latter decades of the 20th century describing its effectiveness in cleaning up wounds. More recently its effectiveness has been compared with that of modern debriding agents, and honey has been found to work more rapidly than all except larval therapy. A randomised controlled trial demonstrated significantly better debriding with honey than with hydrogel. Other trials have shown that honey is a good alternative to surgical debridement for the treatment of necrotising fasciitis in the genital region. Seven case series and ten single case studies have also been published in which the effectiveness of honey in debriding wounds was reported. A prophylactic action of honey has also been reported, where in a randomised controlled trials comparing honey with silver sulfadiazine for the treatment of burns there was no eschar formed with honey but there was eschar formed in the cases treated with silver sulfadiazine. A similar finding has been reported in an animal model, where adjacent experimental wounds were kept clean with honey-soaked gauze but formed thick dense scabs where treated with saline-soaked gauze. The mechanism of action of honey is as yet unknown, but appears to be by way of stimulating autolytic debridement. Additional advantages using honey rather than other moist debridement are that its antibacterial action prevents bacterial growth from being encouraged, and its osmolarity prevents maceration of periwound skin.

year: 2009

title: Experiences of New Zealand Māori mothers’ Engagement with health and social services post-COVID-19 2020 lockdown

authors: Barrett, Nikki Maree

subjects: Childbirth

abstract: Background: 
Despite universal provision of maternity care, Māori (Indigenous peoples of Aotearoa/New Zealand) experience significant maternal and infant health disparities compared to their dominant Pākehā (non-Māori) counterparts. This paper examined the lived realities of postnatal Māori māmā (mothers) engaging with health and social services. Enablers and barriers were identified to better understand what is required to strengthen health services’ responsiveness to Māori māmā health needs and aspirations. 

Methods: 
Underpinned by Kaupapa Māori research principles, which are grounded in Māori cultural values, emphasising self-determination, and Māori aspirations, a small cohort of 17 expectant Māori māmā were recruited from a Māori childbirth education programme to participate in a three-phase study. Phase three, the focus of this paper, involved seven semi-structured, open-ended telephone interviews with Māori māmā. A thematic analysis, underpinned by a mana wahine (authority inherent in Māori women) theoretical perspective amplified these experiences. 

Results: 
Five themes were identified that encapsulated participants’ engagement and interactions with health and social services. These themes were as follows: (1) right to enact tino rangatiratanga (autonomy) and self-achievement; (2) responsiveness of services; (3) service and system issues; (4) need for greater choice and opportunity; and (5) impact of COVID-19. 

Conclusions: 
This study privileged the voices of Māori wāhine, highlighting their experiences with a complex and often unresponsive health system. Participants valued services that enabled them to exercise tino rangatiratanga. Echoing the experiences of other Indigenous Peoples, incorporating culturally relevant practices into perinatal health services is crucial for achieving health equity and addressing disparities.

text: Experiences of New Zealand Māori mothers’ Engagement with health and social services post-COVID-19 2020 lockdown Background: 
Despite universal provision of maternity care, Māori (Indigenous peoples of Aotearoa/New Zealand) experience significant maternal and infant health disparities compared to their dominant Pākehā (non-Māori) counterparts. This paper examined the lived realities of postnatal Māori māmā (mothers) engaging with health and social services. Enablers and barriers were identified to better understand what is required to strengthen health services’ responsiveness to Māori māmā health needs and aspirations. 

Methods: 
Underpinned by Kaupapa Māori research principles, which are grounded in Māori cultural values, emphasising self-determination, and Māori aspirations, a small cohort of 17 expectant Māori māmā were recruited from a Māori childbirth education programme to participate in a three-phase study. Phase three, the focus of this paper, involved seven semi-structured, open-ended telephone interviews with Māori māmā. A thematic analysis, underpinned by a mana wahine (authority inherent in Māori women) theoretical perspective amplified these experiences. 

Results: 
Five themes were identified that encapsulated participants’ engagement and interactions with health and social services. These themes were as follows: (1) right to enact tino rangatiratanga (autonomy) and self-achievement; (2) responsiveness of services; (3) service and system issues; (4) need for greater choice and opportunity; and (5) impact of COVID-19. 

Conclusions: 
This study privileged the voices of Māori wāhine, highlighting their experiences with a complex and often unresponsive health system. Participants valued services that enabled them to exercise tino rangatiratanga. Echoing the experiences of other Indigenous Peoples, incorporating culturally relevant practices into perinatal health services is crucial for achieving health equity and addressing disparities.

year: 2025