title: Oral ketone supplementation: effect on cognitive function, physiology and exercise performance

authors: Rodger, Shem

subjects: Ergogenic

abstract: Nutritional strategies play an important role in facilitating peak athletic performances and research has shown that a state of physiological ketosis, from either a ketogenic diet or ketone supplementation, may have several benefits for athletes. These ergogenic properties may stem from the thermodynamic advantages ketones possess over other energy substrates as well as their ability to preserve glucose stores. Physiological ketosis has also shown improvements in cognitive performance, particularly for those suffering from neurological disease. The following thesis uses an oral ketone supplement (sodium- and potassium-based β-hydroxybutyrate) to elevate blood ketone concentrations to assess the effects of supplement induced ketosis on exercise metabolism and cycling performance (study 1, Chapter 2), as well as its effect on cognitive performance in an active population (study two, Chapter 3). As part of study 1, Twelve participants took part in a double-blind, placebo-controlled, randomised crossover design. The research assessed the effect of supplement-induced ketosis on 4 minute all-out cycling performance which followed 90 minutes at second ventilatory threshold (VT2). Upon ingestion of a ketone supplement (KET: 30 ml of Ketoforce; Prototype Nutrition, IL, USA) or placebo (PLA: 3g table salt; NaCl), effect size (ES) analysis, revealed an unclear 2.3 ±4.8% (Δ mean ±90% Confidence Interval (CI)) change  in power output during a 4-minute maximal cycling performance test (4PT) in the KET trial compared to PLA. Therefore no substantial performance outcomes came as a result of ketone supplementation despite a three-fold increase in blood β-hydroxybutyrate concentration (ES ±90% CI= 3.02 ±0.8; very large) which was accompanied by a 2.2 ±1.9% increase in the respiratory exchange ratio (RER) during the submaximal exercise phase (ES = 0.51 ±0.4; moderate). During the 4PT increases in both VO2 (2.4 ±3.3%; ES = 0.24 ±0.3; small) and RER (4.3 ±3.3; ES = 0.75 ±0.5, moderate) were evident during the KET trial compared to the PLA. 
Similarly in study 2, the effects of oral ketone supplementation on cognitive function were assessed. Using a single blind, placebo-controlled design cognitive function was evaluated through five tests intended to assess different components of neuro-muscular performance, reaction time, processing speed and memory recall: finger tap test (FTT), stroop test (ST), reaction time test (RT), monkey-ladder test (MLT) and one-card test (OCT). The reliability of each test was also assessed using a test-retest protocol. No statistically significant differences (p > 0.05) were observed in cognitive function between groups. ES analysis revealed small improvements in the KET trial for ST (ES = 0.34 ±0.4) as well as the MLT (ES = 0.34 ±0.4) with either trivial or unclear results for FTT, RT and OCT when compared to PLA. In conclusion, ingestion of an oral ketone supplement was shown to have no substantial impact on human performance as measured through 4-minute cycling performance and measures of cognitive function.

text: Oral ketone supplementation: effect on cognitive function, physiology and exercise performance Nutritional strategies play an important role in facilitating peak athletic performances and research has shown that a state of physiological ketosis, from either a ketogenic diet or ketone supplementation, may have several benefits for athletes. These ergogenic properties may stem from the thermodynamic advantages ketones possess over other energy substrates as well as their ability to preserve glucose stores. Physiological ketosis has also shown improvements in cognitive performance, particularly for those suffering from neurological disease. The following thesis uses an oral ketone supplement (sodium- and potassium-based β-hydroxybutyrate) to elevate blood ketone concentrations to assess the effects of supplement induced ketosis on exercise metabolism and cycling performance (study 1, Chapter 2), as well as its effect on cognitive performance in an active population (study two, Chapter 3). As part of study 1, Twelve participants took part in a double-blind, placebo-controlled, randomised crossover design. The research assessed the effect of supplement-induced ketosis on 4 minute all-out cycling performance which followed 90 minutes at second ventilatory threshold (VT2). Upon ingestion of a ketone supplement (KET: 30 ml of Ketoforce; Prototype Nutrition, IL, USA) or placebo (PLA: 3g table salt; NaCl), effect size (ES) analysis, revealed an unclear 2.3 ±4.8% (Δ mean ±90% Confidence Interval (CI)) change  in power output during a 4-minute maximal cycling performance test (4PT) in the KET trial compared to PLA. Therefore no substantial performance outcomes came as a result of ketone supplementation despite a three-fold increase in blood β-hydroxybutyrate concentration (ES ±90% CI= 3.02 ±0.8; very large) which was accompanied by a 2.2 ±1.9% increase in the respiratory exchange ratio (RER) during the submaximal exercise phase (ES = 0.51 ±0.4; moderate). During the 4PT increases in both VO2 (2.4 ±3.3%; ES = 0.24 ±0.3; small) and RER (4.3 ±3.3; ES = 0.75 ±0.5, moderate) were evident during the KET trial compared to the PLA. 
Similarly in study 2, the effects of oral ketone supplementation on cognitive function were assessed. Using a single blind, placebo-controlled design cognitive function was evaluated through five tests intended to assess different components of neuro-muscular performance, reaction time, processing speed and memory recall: finger tap test (FTT), stroop test (ST), reaction time test (RT), monkey-ladder test (MLT) and one-card test (OCT). The reliability of each test was also assessed using a test-retest protocol. No statistically significant differences (p > 0.05) were observed in cognitive function between groups. ES analysis revealed small improvements in the KET trial for ST (ES = 0.34 ±0.4) as well as the MLT (ES = 0.34 ±0.4) with either trivial or unclear results for FTT, RT and OCT when compared to PLA. In conclusion, ingestion of an oral ketone supplement was shown to have no substantial impact on human performance as measured through 4-minute cycling performance and measures of cognitive function.

year: 2015

title: Forest canopy restoration has indirect effects on litter decomposition and no effect on denitrification

authors: Wallace, Kiri Joy

subjects: Science & Technology

abstract: Forest restoration has potential to recover degraded ecosystem functions in disturbed environments. Decomposition and denitrification are two critical functions involved in forest nutrient cycling that are often compromised in degraded ecosystems. As forest canopy structure develops following initial plantings, it may indirectly impact ecosystem functions by altering abiotic conditions. It is likely, however, that there are other abiotic factors that affect decomposition and denitrification that are unrelated to forest canopy structure. Here, we aimed to determine whether forest canopy openness, topography, and soil sand content would affect litter decomposition and denitrification by regulating the microclimate, the herbaceous plant layer, soil chemistry, and soil moisture. Research occurred in restored native temperate rainforest patches in two New Zealand cities. Urban forests are an excellent context for measuring impact of canopy restoration on ecosystem properties such as microclimate due to the extreme swings in city conditions (e.g., urban heat island). Decomposition rates were determined using leaf litter bags and denitrification rates through denitrification enzyme activity assays. We used structural equation modeling to quantify the direct and indirect drivers of these ecosystem functions. Results indicated that decomposition rates were positively related to soil moisture, relative humidity, and herbaceous plant cover. Interestingly, forest canopy openness indirectly affected decomposition through counteracting forces, meaning greater canopy openness in young forests permitted dense herbaceous plant growth which enhanced decomposition, while less canopy openness in older forests enhanced humidity levels which increased decomposition. Denitrification was negatively related to soil pH and positively related to soil moisture, but these abiotic factors were unrelated to the forest canopy. Discovering drivers of ecosystem functions can improve approaches to the restoration of degraded ecosystems, especially in disturbed urban areas. Identifying counteracting effects on ecosystem functions could improve management by focusing restoration actions on specific drivers to elicit desired changes. Some ecosystem processes, like denitrification, are not affected by forest canopy restoration or management, but are instead driven by edaphic and landscape factors.

text: Forest canopy restoration has indirect effects on litter decomposition and no effect on denitrification Forest restoration has potential to recover degraded ecosystem functions in disturbed environments. Decomposition and denitrification are two critical functions involved in forest nutrient cycling that are often compromised in degraded ecosystems. As forest canopy structure develops following initial plantings, it may indirectly impact ecosystem functions by altering abiotic conditions. It is likely, however, that there are other abiotic factors that affect decomposition and denitrification that are unrelated to forest canopy structure. Here, we aimed to determine whether forest canopy openness, topography, and soil sand content would affect litter decomposition and denitrification by regulating the microclimate, the herbaceous plant layer, soil chemistry, and soil moisture. Research occurred in restored native temperate rainforest patches in two New Zealand cities. Urban forests are an excellent context for measuring impact of canopy restoration on ecosystem properties such as microclimate due to the extreme swings in city conditions (e.g., urban heat island). Decomposition rates were determined using leaf litter bags and denitrification rates through denitrification enzyme activity assays. We used structural equation modeling to quantify the direct and indirect drivers of these ecosystem functions. Results indicated that decomposition rates were positively related to soil moisture, relative humidity, and herbaceous plant cover. Interestingly, forest canopy openness indirectly affected decomposition through counteracting forces, meaning greater canopy openness in young forests permitted dense herbaceous plant growth which enhanced decomposition, while less canopy openness in older forests enhanced humidity levels which increased decomposition. Denitrification was negatively related to soil pH and positively related to soil moisture, but these abiotic factors were unrelated to the forest canopy. Discovering drivers of ecosystem functions can improve approaches to the restoration of degraded ecosystems, especially in disturbed urban areas. Identifying counteracting effects on ecosystem functions could improve management by focusing restoration actions on specific drivers to elicit desired changes. Some ecosystem processes, like denitrification, are not affected by forest canopy restoration or management, but are instead driven by edaphic and landscape factors.

year: 2018

title: Transitioning from kōhanga reo to kura

authors: Hohepa, Margie Kahukura

abstract: This is a collaborative cross-sector research project involving a kōhanga reo (Māori immersion early childhood language nest) kura (Māori language immersion school) and university-based researchers. It focuses on tamariki (children) moving from kōhanga reo to kura classrooms and will examine the development of an 'akoranga whakawhiti', a transition programme that will be based at Te Kōhanga Reo o Ngā Kuaka in Hamilton. The over arching research question for this project is: Pēhea rā te āhuatanga me te kounga o ngā whakawhitinga mai i te kōhanga ki te kura mō ngā tamariki, whānau, kaiako me te hāpori? - What do effective transitions from kōhanga reo to kura look like, feel like, and sound like, for tamariki, whānau, kaiako and the community? The project aims to provide important new insights into learning and teaching in Māori-medium settings and into ways of enhancing transitions from Maori-medium early childhood education to Māori medium classrooms.

text: Transitioning from kōhanga reo to kura This is a collaborative cross-sector research project involving a kōhanga reo (Māori immersion early childhood language nest) kura (Māori language immersion school) and university-based researchers. It focuses on tamariki (children) moving from kōhanga reo to kura classrooms and will examine the development of an 'akoranga whakawhiti', a transition programme that will be based at Te Kōhanga Reo o Ngā Kuaka in Hamilton. The over arching research question for this project is: Pēhea rā te āhuatanga me te kounga o ngā whakawhitinga mai i te kōhanga ki te kura mō ngā tamariki, whānau, kaiako me te hāpori? - What do effective transitions from kōhanga reo to kura look like, feel like, and sound like, for tamariki, whānau, kaiako and the community? The project aims to provide important new insights into learning and teaching in Māori-medium settings and into ways of enhancing transitions from Maori-medium early childhood education to Māori medium classrooms.

year: 2014