George A,Brooks的突出贡献是对乳酸的研究,他推翻了希尔的氧债假说,创立和发展了乳酸穿梭学说,并得到了运动生理学界内外的普遍认可。搜集Brooks近50年的论文、新闻以及同行争议与评价,从认识论角度梳理其对乳酸的研究历史和观点,基于...George A,Brooks的突出贡献是对乳酸的研究,他推翻了希尔的氧债假说,创立和发展了乳酸穿梭学说,并得到了运动生理学界内外的普遍认可。搜集Brooks近50年的论文、新闻以及同行争议与评价,从认识论角度梳理其对乳酸的研究历史和观点,基于研究者视角树立运动“代谢物”的认识过程和方法。Brooks认为,乳酸具有能量底物、电子载体、信号分子三重角色,乳酸变化在不同生理环境下产生截然不同的效益。Brooks的乳酸简史从认识论和方法论上都给我们以深刻启示和教训,对运动“代谢物”的认识切忌片面化和主观的价值导向。在面对很多实验结果时有必要事先推定,运动内源性“代谢物”具有多重角色,只有在特定生理或病理条件下表现“好”与“坏”。运动生理学家须致力于用运动刺激的特殊模型,揭示深层次、普适性的生理学机制,对运动生理、健康生理、病理生理给予统一解释,从繁杂的实验结论中创造与实验数据吻合的学说。展开更多
Background：Forests contribute to human wellbeing through the provision of important ecosystem services.Methods：In this study,we investigated how the perceived importance of ecosystem services may impact the overall ...Background：Forests contribute to human wellbeing through the provision of important ecosystem services.Methods：In this study,we investigated how the perceived importance of ecosystem services may impact the overall benefit provided by managed watersheds at the Hubbard Brook Experimental Forest over a 45-year period,using standardized measures of service capacity weighted by service importance weights derived from a survey of beneficiaries.Results：The capacity of watersheds to regulate water flow and quality was high in all watersheds throughout the study period,whereas cultural services such as scenic beauty declined after harvest.Impacts on greenhouse gas regulation depended on the efficiency with which harvested biomass was used.Surveys revealed that stakeholders placed high value on all ecosystem services,with regulating and cultural services seen as more important than provisioning services.When service metrics were weighted by survey responses and aggregated into a single measure,total service provision followed the same overall trend as greenhouse gas regulation.Where biomass use was less efficient in terms of greenhouse gas emissions,harvesting resulted in an overall ＂ecosystem service debt＂;where use was more efficient,this ＂ecosystem service debt＂ was reduced.Beneficiaries＇ educational backgrounds significantly affected overall assessment of service provision.Beneficiaries with college or university degrees incurred smaller ＂ecosystem service debts＂ and were less negatively affected by harvesting overall.Conclusions：This study highlights the importance of including empirical measures of beneficiary preference when attempting to quantify overall provision of ecosystem services to human beneficiaries over time.展开更多
Arctic Alaska is a ＇suspect＇ terrane that encompasses approximately 20%of Alaska,stretching from the southern Brooks Range all the way to the continental shelves of the Chukchi and Beaufort Seas.Although the origin ...Arctic Alaska is a ＇suspect＇ terrane that encompasses approximately 20%of Alaska,stretching from the southern Brooks Range all the way to the continental shelves of the Chukchi and Beaufort Seas.Although the origin and subsequent travels of this large crustal fragment are debated among geologists,most researchers agree upon its composite nature and exotic origin.To constrain the early geological history of this terrane,we describe a recent expedition to the Doonerak fenster of the central Brooks Range.This area has long been regarded as a key locality for understanding the structural evolution of the Mesozoic-Cenozoic Brooks Range orogen;however,our target was different：a unique sequence of volcanic and siliciclastic rocks（Apoon assemblage） exposed beneath a profound pre-Mississippian unconformity,which we argue is of key importance to understanding the early Paleozoic tectonic history of northern Alaska and the greater Arctic.展开更多
Peatland drainage can affect headwater systems, causing changes in bed substrate composition and hydraulic geome-try in small brooks. We studied hydraulic geometry and sediment properties in 14 boreal forest brook rea...Peatland drainage can affect headwater systems, causing changes in bed substrate composition and hydraulic geome-try in small brooks. We studied hydraulic geometry and sediment properties in 14 boreal forest brook reaches (width < 2 m), characterised by well-vegetated banks, high sinuosity and low width-to-depth ratio, in north-east Finland. The aims were to obtain information from channel geometry and to study brook response to extensive sediment load from land use. The results indicate that bed sediment in brooks is almost continuously mobile, which negatively reflect to ecological status of the brooks. These headwater meandering parts have limited sediment transport capacity and require a long period to recover from artificially increased sediment input from peat drainage. However, different reaches can be prioritised for restoration according to the characteristics of silted bed sediment or sediment origins. Brook width appeared to have large natural variation, causing great local velocity variations. This needs to be taken into consideration when restoring straightened reaches in small headwater areas, e.g., width in restored reaches cannot be uniform but should include variations.展开更多
Michael Brooks在非洲出生及成长,在11个国家居住过,是一位名副其实的世界公民。他拥有超过40年的专业酒店管理经验,毕业于瑞士洛桑酒店管理学院,曾于欧洲、非洲、澳洲及中国的酒店任职。现时,他负责阿丽拉集团首家度假村的开幕事宜;浙...Michael Brooks在非洲出生及成长,在11个国家居住过,是一位名副其实的世界公民。他拥有超过40年的专业酒店管理经验,毕业于瑞士洛桑酒店管理学院,曾于欧洲、非洲、澳洲及中国的酒店任职。现时,他负责阿丽拉集团首家度假村的开幕事宜;浙江安吉阿丽拉度假村拥有茂密的竹林及清新的茶园,电影＂卧虎藏龙＂亦在此取景。展开更多
This study presents an extended version of a single site daily weather generator after Richardson. The model is driven by daily precipitation series derived by a first-order two-state Markov chain and considers the an...This study presents an extended version of a single site daily weather generator after Richardson. The model is driven by daily precipitation series derived by a first-order two-state Markov chain and considers the annual cycle of each meteorological variable. The evaluation of its performance was done by deploying its synthetic time series into the physical based hydrological model BROOK90. The weather generator was applied and tested for data from the Anchor Station at the Tharandt Forest, Germany. Additionally its results were compared to the output of another weather generator with spell-length approach for the precipitation series (LARS-WG). The comparison was distinguished into a meteoro-logical and a hydrological part in terms of extremes, monthly and annual sums and averages. Extreme events could be preserved adequately by both models. Nevertheless a general underestimation of rare events was observed. Natural correlations between vapour pressure and minimum temperature could be conserved as well as annual cycles of the hydro-logical and meteorological regime. But the simulated spectrums of extremes, especially, of precipitation and temperature, are more limited than the observed spectrums. While LARS-WG already finds application in practice, the results show that the data derived from the presented weather generator is as useful and reliable as those from the established model for the simulation of the water balance.展开更多
Gwendolyn Brooks is one of the most significant American poets.She mainly depicts the ordinary black people and their daily lives,especially the complexity of the lives of the poor black people in her later poetry.Thi...Gwendolyn Brooks is one of the most significant American poets.She mainly depicts the ordinary black people and their daily lives,especially the complexity of the lives of the poor black people in her later poetry.This paper attempts to employ her several typical poems to explore the image of African-American black people from the perspective of post-colonialism.展开更多
基金support from the USDA Forest Service's Northeastern States Research Cooperative(NSRC)in collaboration with the Hubbard Brook Research Foundationthe Cary Institute of Ecosystem Studies
文摘Background：Forests contribute to human wellbeing through the provision of important ecosystem services.Methods：In this study,we investigated how the perceived importance of ecosystem services may impact the overall benefit provided by managed watersheds at the Hubbard Brook Experimental Forest over a 45-year period,using standardized measures of service capacity weighted by service importance weights derived from a survey of beneficiaries.Results：The capacity of watersheds to regulate water flow and quality was high in all watersheds throughout the study period,whereas cultural services such as scenic beauty declined after harvest.Impacts on greenhouse gas regulation depended on the efficiency with which harvested biomass was used.Surveys revealed that stakeholders placed high value on all ecosystem services,with regulating and cultural services seen as more important than provisioning services.When service metrics were weighted by survey responses and aggregated into a single measure,total service provision followed the same overall trend as greenhouse gas regulation.Where biomass use was less efficient in terms of greenhouse gas emissions,harvesting resulted in an overall ＂ecosystem service debt＂;where use was more efficient,this ＂ecosystem service debt＂ was reduced.Beneficiaries＇ educational backgrounds significantly affected overall assessment of service provision.Beneficiaries with college or university degrees incurred smaller ＂ecosystem service debts＂ and were less negatively affected by harvesting overall.Conclusions：This study highlights the importance of including empirical measures of beneficiary preference when attempting to quantify overall provision of ecosystem services to human beneficiaries over time.
基金supported by a Geological Society of America graduate student research grant,Harvard University,Dartmouth Collegea National Science Foundation(NSF) Tectonics grant (EAR-1624131)+1 种基金supported by a Stanford McGee Grantand a NSF Graduate Research Fellowshipsupported by Harvard University
文摘Arctic Alaska is a ＇suspect＇ terrane that encompasses approximately 20%of Alaska,stretching from the southern Brooks Range all the way to the continental shelves of the Chukchi and Beaufort Seas.Although the origin and subsequent travels of this large crustal fragment are debated among geologists,most researchers agree upon its composite nature and exotic origin.To constrain the early geological history of this terrane,we describe a recent expedition to the Doonerak fenster of the central Brooks Range.This area has long been regarded as a key locality for understanding the structural evolution of the Mesozoic-Cenozoic Brooks Range orogen;however,our target was different：a unique sequence of volcanic and siliciclastic rocks（Apoon assemblage） exposed beneath a profound pre-Mississippian unconformity,which we argue is of key importance to understanding the early Paleozoic tectonic history of northern Alaska and the greater Arctic.
基金partly funded by the forest brook restoration project led by the North Ostrobothnia Regional Environment Centre in Finlandsupport from KIRSU graduate school(Academy of Finland),Tor and Maj Nessling foundation,MVTT,Thule-institute at University of Oulu,Mod-Stream project by Academy of Finland and the Ministry of Agriculture and Forestry.
文摘Peatland drainage can affect headwater systems, causing changes in bed substrate composition and hydraulic geome-try in small brooks. We studied hydraulic geometry and sediment properties in 14 boreal forest brook reaches (width < 2 m), characterised by well-vegetated banks, high sinuosity and low width-to-depth ratio, in north-east Finland. The aims were to obtain information from channel geometry and to study brook response to extensive sediment load from land use. The results indicate that bed sediment in brooks is almost continuously mobile, which negatively reflect to ecological status of the brooks. These headwater meandering parts have limited sediment transport capacity and require a long period to recover from artificially increased sediment input from peat drainage. However, different reaches can be prioritised for restoration according to the characteristics of silted bed sediment or sediment origins. Brook width appeared to have large natural variation, causing great local velocity variations. This needs to be taken into consideration when restoring straightened reaches in small headwater areas, e.g., width in restored reaches cannot be uniform but should include variations.
基金supported by the German Academic Exchange Service(DAAD).
文摘This study presents an extended version of a single site daily weather generator after Richardson. The model is driven by daily precipitation series derived by a first-order two-state Markov chain and considers the annual cycle of each meteorological variable. The evaluation of its performance was done by deploying its synthetic time series into the physical based hydrological model BROOK90. The weather generator was applied and tested for data from the Anchor Station at the Tharandt Forest, Germany. Additionally its results were compared to the output of another weather generator with spell-length approach for the precipitation series (LARS-WG). The comparison was distinguished into a meteoro-logical and a hydrological part in terms of extremes, monthly and annual sums and averages. Extreme events could be preserved adequately by both models. Nevertheless a general underestimation of rare events was observed. Natural correlations between vapour pressure and minimum temperature could be conserved as well as annual cycles of the hydro-logical and meteorological regime. But the simulated spectrums of extremes, especially, of precipitation and temperature, are more limited than the observed spectrums. While LARS-WG already finds application in practice, the results show that the data derived from the presented weather generator is as useful and reliable as those from the established model for the simulation of the water balance.
文摘Gwendolyn Brooks is one of the most significant American poets.She mainly depicts the ordinary black people and their daily lives,especially the complexity of the lives of the poor black people in her later poetry.This paper attempts to employ her several typical poems to explore the image of African-American black people from the perspective of post-colonialism.
