The effect of macadamia nut shell biochar on nitrogen,potassium,phosphorus,magnesium,calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experimen...The effect of macadamia nut shell biochar on nitrogen,potassium,phosphorus,magnesium,calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment.The treatments combined two fertiliser rates（50 and 100% rate of the commercial mix commonly used in forestry nurseries） with eight biochar rates(0,2,5,10,20,50,80 and 100 t ha;) arranged in a randomised complete block with three replicates of four sample plants.Nutrients were quantified in the potting mix and seedling leaves at four destructive harvests 135,177,219 and269 days after planting.Biochar significantly increased nitrate-N,Colwell P,Colwell K and exchangeable Na andreduced ammonium-N,Mg and Ca concentrations in the potting mix.Seedling leaf concentrations of P,K and Na were increased by biochar application,while N remained dependent on fertiliser rate only.Mg and Ca leaf concentrations decreased in response to increasing biochar rates.Elevated nitrate-N and decreased ammonium-N concentrations suggest that biochar might have increased nitrification in the potting mix.We presumed that biochar mediated processes that reduced uptake of P and K when high doses of biochar were combined with full fertilisation.Changes in potting mix K,Na,Mg and Ca were consistent with selective adsorption of ions to biochar surfaces.展开更多
Objectives The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool,ambient conditions using a two-pill ingestion strategy.Methods T...Objectives The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool,ambient conditions using a two-pill ingestion strategy.Methods Thirty-two recreational runners(age:38.7±10.2 years,mass:73.9±11.0 kg,height:177±8 cm)were invited to participate in this study.Core temperature was continuously assessed using telemetric ingestible pills.Each runner swallowed two pills:the first pill(Pill 1)11 h:47 min±1 h:01 min pre-race(before overnight sleep)and the second(Pill 2)2 h:35 min±0 h:54 min pre-race(on wakening).Results Pre-race core temperature for Pill 1 was significantly different from Pill 2,with values of 37.4±0.4℃and 37.1±0.6℃,respectively(p=0.006).The mean core temperature during the race was higher for Pill 1 compared to Pill 2(38.5±0.5℃and 37.8±1.0℃,respectively;p<0.001).Peak core temperature was higher for Pill 1 compared to Pill 2(39.1±0.5℃and 38.8±0.5℃,respectively;p=0.03).Post-race core temperature was higher for Pill 1 compared to Pill 2(38.8±0.7℃and 38.1±1.3℃,respectively;p=0.02).Conclusions The timing of pill ingestion significantly impacted core temperature and hence timing of pill ingestion should be standardised(5 h:30 min–7 h prior to measurement).Despite the relatively cool ambient conditions during the race,a significant number of runners achieved a high core body temperature(≥39℃),which was not accompanied by any signs of heat illness.展开更多
In this article the affiliation details for Author Sebastien Racinais were incorrectly given as‘UMR 866 INRAE/University of Montpellier,DMEM,Montpellier,France’but should have been‘DMEM,Univ Montpellier,INRAE,Montp...In this article the affiliation details for Author Sebastien Racinais were incorrectly given as‘UMR 866 INRAE/University of Montpellier,DMEM,Montpellier,France’but should have been‘DMEM,Univ Montpellier,INRAE,Montpellier,France’.展开更多
Purpose Whilst modifications in thermoregulatory responses and plasma volume during heat acclimation(HA)are well researched,much less is known regarding hemoglobin mass.The aim of this study was to investigate the hem...Purpose Whilst modifications in thermoregulatory responses and plasma volume during heat acclimation(HA)are well researched,much less is known regarding hemoglobin mass.The aim of this study was to investigate the hematological adaptations associated with a long-term,progressive,work-matched controlled heart rate HA protocol.Methods Ten males(VO_(2peak):4.50±0.50 L/min)completed two three-week training interventions consisting of HA(36℃ and 59%RH)and exercise in temperate conditions(TEMP:18℃ and 60%RH)in a counter-balanced crossover design.Weekly training included 5 consecutive laboratory-based sessions(i.e.4 controlled heart rate training and 1 repeated sprint training)and 2 days off.Results Hemoglobin mass decreased from day 4 of training in HA(-22[-37,-8]g,P<0.001)but not TEMP(+2[-12,+17]g,P=0.743),returning to baseline at the end of HA(-7[-22,+7]g,P=0.333).As compared to day 1,several other adaptations were present from day 5 onward in HA including a decrease in heart rate at rest(-4[-8,-0]beats/min,P=0.040)and at a given work rate(-6[-10,-1]beats/min,P=0.012),an increase in whole-body sweat rate(+0.3[+0.1,+0.5]L/h,P=0.015),and an increase in power output(+18[+8,+28]W,P<0.001);while there was no changes in TEMP(P≥0.143).Plasma volume increased in both HA(+168[+23,+314]mL)and TEMP(+166[+20,+311]mL)by the 11th day of training(P≤0.027).Conclusion While training in both hot or temperate conditions led to plasma volume increases,training in the heat lead to specific physiological adaptations,including a transient decrease in hemoglobin mass that was rapidly reversed within a few days of HA.展开更多
Purpose The aim of this study was to confirm the impact of heat acclimation on aerobic performance in hot conditions and elucidate the transfer of heat adaptations to cool and hypoxic environments.Methods Ten males(VO...Purpose The aim of this study was to confirm the impact of heat acclimation on aerobic performance in hot conditions and elucidate the transfer of heat adaptations to cool and hypoxic environments.Methods Ten males(VO_(2peak):4.50±0.50 L/min)completed two three-week interventions consisting of heat acclimation(HA:36℃ and 59%RH)and temperate training(TEMP:18℃ and 60%RH)in a counter-balanced crossover design.Train-ing weeks consisted of four work-matched controlled heart rate sessions interspersed with one intermittent sprint session,and two rest days.Before and after the interventionsVO_(2peak) and 20-min time trial performance were evaluated in COOL(18℃),HOT(35℃)and hypoxic(HYP:18℃ andFiO_(2):15.4%)conditions.Results Following HA,VO_(2peak) increased significantly in HOT(0.24 L/min[0.01,0.47],P=0.040)but not COOL(P=0.431)or HYP(P=0.411),whereas TEMP had no influence onVO_(2peak)(P≥0.424).Mean time trial power output increased sig-nificantly in HOT(20 W[11,28],P<0.001)and COOL(12 W[4,21],P=0.004),but not HYP(7 W[-1,16],P=0.075)after HA,whereas TEMP had no influence on mean power output(P≥0.110).Rectal(-0.13℃[-0.23,-0.03],P=0.009)and skin(-0.7℃[-1.2,-0.3],P<0.001)temperature were lower during the time trial in HOT after HA,whereas mean heart rate did not differ(P=0.339).Conclusions HA improved aerobic performance in HOT in conjunction with lower thermal strain and enhanced cardiovas-cular stability(similar heart rate for higher workload),whereas the mechanistic pathways improving performance in COOL and HYP remain unclear.展开更多
Elite athletes will compete in extreme heat more frequently as global land and sea temperatures increase,alongside more intense,frequent and longer duration heatwaves.Best practices to protect athlete health and perfo...Elite athletes will compete in extreme heat more frequently as global land and sea temperatures increase,alongside more intense,frequent and longer duration heatwaves.Best practices to protect athlete health and performance during competition include heat acclimation/acclimatisation[(HA);i.e.,long-term pre-competition preparation]complemented by pre-planned and practised cooling and hydration strategies(i.e.,short-term interventions immediately before or during competition).This review explores elite athletes’current behaviours and practices when preparing for competition in the heat and assesses the level of knowledge that has been exhibited by athletes and their practitioners in this space.Recommendations for future research,discussions of current best practices,and methods to improve translation of research into practice are provided.Available research focuses on small samples of elite endurance athletes during a selection of World Championship/Olympic/Paralympic events(~6%of competing athletes).While generally an increase in the adoption of evidence-based HA is seen chronologically from 2015 onwards,universal adoption is not seen.HA adoption is lowest in those who live/train in cold/temperate environments with cost and access to facilities/equipment being the most commonly reported barriers.Further research is required across the sporting landscape to fully characterise elite athlete behaviours and practices in these spaces.International federations and national governing bodies should continue their efforts to educate athletes and focus on regularly updated and reinvigorated release of evidence-based guidelines(in multiple germane languages)for competing in the heat,to increase the adoption of HA and other heat related best practice.展开更多
基金Forestry Tasmaniap,BHP Billiton TEMCO Community FoundationTasmanian Community Fund+1 种基金Centre for Renewable Energy and Power Systems(CREPS)Rainbow Bee Eater Project for their support
文摘The effect of macadamia nut shell biochar on nitrogen,potassium,phosphorus,magnesium,calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment.The treatments combined two fertiliser rates（50 and 100% rate of the commercial mix commonly used in forestry nurseries） with eight biochar rates(0,2,5,10,20,50,80 and 100 t ha;) arranged in a randomised complete block with three replicates of four sample plants.Nutrients were quantified in the potting mix and seedling leaves at four destructive harvests 135,177,219 and269 days after planting.Biochar significantly increased nitrate-N,Colwell P,Colwell K and exchangeable Na andreduced ammonium-N,Mg and Ca concentrations in the potting mix.Seedling leaf concentrations of P,K and Na were increased by biochar application,while N remained dependent on fertiliser rate only.Mg and Ca leaf concentrations decreased in response to increasing biochar rates.Elevated nitrate-N and decreased ammonium-N concentrations suggest that biochar might have increased nitrification in the potting mix.We presumed that biochar mediated processes that reduced uptake of P and K when high doses of biochar were combined with full fertilisation.Changes in potting mix K,Na,Mg and Ca were consistent with selective adsorption of ions to biochar surfaces.
文摘Objectives The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool,ambient conditions using a two-pill ingestion strategy.Methods Thirty-two recreational runners(age:38.7±10.2 years,mass:73.9±11.0 kg,height:177±8 cm)were invited to participate in this study.Core temperature was continuously assessed using telemetric ingestible pills.Each runner swallowed two pills:the first pill(Pill 1)11 h:47 min±1 h:01 min pre-race(before overnight sleep)and the second(Pill 2)2 h:35 min±0 h:54 min pre-race(on wakening).Results Pre-race core temperature for Pill 1 was significantly different from Pill 2,with values of 37.4±0.4℃and 37.1±0.6℃,respectively(p=0.006).The mean core temperature during the race was higher for Pill 1 compared to Pill 2(38.5±0.5℃and 37.8±1.0℃,respectively;p<0.001).Peak core temperature was higher for Pill 1 compared to Pill 2(39.1±0.5℃and 38.8±0.5℃,respectively;p=0.03).Post-race core temperature was higher for Pill 1 compared to Pill 2(38.8±0.7℃and 38.1±1.3℃,respectively;p=0.02).Conclusions The timing of pill ingestion significantly impacted core temperature and hence timing of pill ingestion should be standardised(5 h:30 min–7 h prior to measurement).Despite the relatively cool ambient conditions during the race,a significant number of runners achieved a high core body temperature(≥39℃),which was not accompanied by any signs of heat illness.
文摘In this article the affiliation details for Author Sebastien Racinais were incorrectly given as‘UMR 866 INRAE/University of Montpellier,DMEM,Montpellier,France’but should have been‘DMEM,Univ Montpellier,INRAE,Montpellier,France’.
文摘Purpose Whilst modifications in thermoregulatory responses and plasma volume during heat acclimation(HA)are well researched,much less is known regarding hemoglobin mass.The aim of this study was to investigate the hematological adaptations associated with a long-term,progressive,work-matched controlled heart rate HA protocol.Methods Ten males(VO_(2peak):4.50±0.50 L/min)completed two three-week training interventions consisting of HA(36℃ and 59%RH)and exercise in temperate conditions(TEMP:18℃ and 60%RH)in a counter-balanced crossover design.Weekly training included 5 consecutive laboratory-based sessions(i.e.4 controlled heart rate training and 1 repeated sprint training)and 2 days off.Results Hemoglobin mass decreased from day 4 of training in HA(-22[-37,-8]g,P<0.001)but not TEMP(+2[-12,+17]g,P=0.743),returning to baseline at the end of HA(-7[-22,+7]g,P=0.333).As compared to day 1,several other adaptations were present from day 5 onward in HA including a decrease in heart rate at rest(-4[-8,-0]beats/min,P=0.040)and at a given work rate(-6[-10,-1]beats/min,P=0.012),an increase in whole-body sweat rate(+0.3[+0.1,+0.5]L/h,P=0.015),and an increase in power output(+18[+8,+28]W,P<0.001);while there was no changes in TEMP(P≥0.143).Plasma volume increased in both HA(+168[+23,+314]mL)and TEMP(+166[+20,+311]mL)by the 11th day of training(P≤0.027).Conclusion While training in both hot or temperate conditions led to plasma volume increases,training in the heat lead to specific physiological adaptations,including a transient decrease in hemoglobin mass that was rapidly reversed within a few days of HA.
文摘Purpose The aim of this study was to confirm the impact of heat acclimation on aerobic performance in hot conditions and elucidate the transfer of heat adaptations to cool and hypoxic environments.Methods Ten males(VO_(2peak):4.50±0.50 L/min)completed two three-week interventions consisting of heat acclimation(HA:36℃ and 59%RH)and temperate training(TEMP:18℃ and 60%RH)in a counter-balanced crossover design.Train-ing weeks consisted of four work-matched controlled heart rate sessions interspersed with one intermittent sprint session,and two rest days.Before and after the interventionsVO_(2peak) and 20-min time trial performance were evaluated in COOL(18℃),HOT(35℃)and hypoxic(HYP:18℃ andFiO_(2):15.4%)conditions.Results Following HA,VO_(2peak) increased significantly in HOT(0.24 L/min[0.01,0.47],P=0.040)but not COOL(P=0.431)or HYP(P=0.411),whereas TEMP had no influence onVO_(2peak)(P≥0.424).Mean time trial power output increased sig-nificantly in HOT(20 W[11,28],P<0.001)and COOL(12 W[4,21],P=0.004),but not HYP(7 W[-1,16],P=0.075)after HA,whereas TEMP had no influence on mean power output(P≥0.110).Rectal(-0.13℃[-0.23,-0.03],P=0.009)and skin(-0.7℃[-1.2,-0.3],P<0.001)temperature were lower during the time trial in HOT after HA,whereas mean heart rate did not differ(P=0.339).Conclusions HA improved aerobic performance in HOT in conjunction with lower thermal strain and enhanced cardiovas-cular stability(similar heart rate for higher workload),whereas the mechanistic pathways improving performance in COOL and HYP remain unclear.
文摘Elite athletes will compete in extreme heat more frequently as global land and sea temperatures increase,alongside more intense,frequent and longer duration heatwaves.Best practices to protect athlete health and performance during competition include heat acclimation/acclimatisation[(HA);i.e.,long-term pre-competition preparation]complemented by pre-planned and practised cooling and hydration strategies(i.e.,short-term interventions immediately before or during competition).This review explores elite athletes’current behaviours and practices when preparing for competition in the heat and assesses the level of knowledge that has been exhibited by athletes and their practitioners in this space.Recommendations for future research,discussions of current best practices,and methods to improve translation of research into practice are provided.Available research focuses on small samples of elite endurance athletes during a selection of World Championship/Olympic/Paralympic events(~6%of competing athletes).While generally an increase in the adoption of evidence-based HA is seen chronologically from 2015 onwards,universal adoption is not seen.HA adoption is lowest in those who live/train in cold/temperate environments with cost and access to facilities/equipment being the most commonly reported barriers.Further research is required across the sporting landscape to fully characterise elite athlete behaviours and practices in these spaces.International federations and national governing bodies should continue their efforts to educate athletes and focus on regularly updated and reinvigorated release of evidence-based guidelines(in multiple germane languages)for competing in the heat,to increase the adoption of HA and other heat related best practice.
