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继承性宇生核素在冰川地貌暴露测年中的研究进展 被引量:1
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作者 张梦媛 梅静 +2 位作者 张志刚 王建 梁兴江 《地球环境学报》 CSCD 2019年第4期325-334,共10页
原地生成宇宙成因核素(in situ terrestrial cosmogenic nuclide,TCN)暴露测年技术已被广泛应用于全球冰川地貌的年代测定中。继承性核素(inheritance,核素残留)作为影响TCN暴露测年的重要因素之一,一直以来受到许多学者的关注。然而,... 原地生成宇宙成因核素(in situ terrestrial cosmogenic nuclide,TCN)暴露测年技术已被广泛应用于全球冰川地貌的年代测定中。继承性核素(inheritance,核素残留)作为影响TCN暴露测年的重要因素之一,一直以来受到许多学者的关注。然而,继承性核素对暴露测年结果有无影响、影响程度有多大还存在争论。梳理该方面的研究将有助于进一步了解继承性宇生核素对TCN暴露测年的影响,进而提高测年的精确性。基于此,整理了2009—2017年共计54篇全球关于第四纪冰川宇生核素继承性文献,简述继承性核素的产生背景和研究进展,重点探讨核素残留对TCN暴露测年的影响程度以及在实际应用中如何降低其对测年数据的影响。结果表明:继承性核素会导致冰碛物出现异常老化和分散的暴露年龄,可通过选取合适的地貌部位及多样化的抽样和多样品方法,也可尝试采集现代冰川冰碛物定量化研究继承性核素的影响。 展开更多
关键词 继承性核素 宇生核素 TCN暴露 冰川地貌 测年误差
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Influence of age in estimating maximal oxygen uptake 被引量:2
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作者 Christina G de Souza Silva Barry A Franklin +1 位作者 Daniel E Forman Claudio Gil S Araujo 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第2期126-131,共6页
Objective To assess the influence of age on the error of estimate (EE) of maximal oxygen uptake (VO2max) using sex and population specific-equations in cycle ergometer exercise testing, since estimated VO2 max is ... Objective To assess the influence of age on the error of estimate (EE) of maximal oxygen uptake (VO2max) using sex and population specific-equations in cycle ergometer exercise testing, since estimated VO2 max is associated with a substantial EE, often exceeding 20%, possibly due to intrinsic variability of mechanical efficiency. Methods 1850 adults (68% men), aged 18 to 91 years, underwent maximal cycle ergometer cardiopulmonary exercise testing. Cardiorespiratory fitness (CRF) was assessed relative to sex and age [younger (18 to 35 years), middle-aged (36 to 60 years) and older (〉 60 years)]. VO2max [mL.(kg.min)-1] was directly measured by assessment of gas exchange and estimated using sex and population specific-equations. Measured and estimated values of VO2max and related EE were compared among the three age- and sex-specific groups. Results Directly measured VO2max of men and women were 29.5 ± 10.5 mL.(kg.min)-1 and 24.2 ± 9.0 mL.(kg·min) -1 (P 〈 0.01). EE [mL·(kg·min)-1] and percent errors (%E) for men and women had similar values, 0.5 ± 3.2 and 0.4 ± 2.9 mL·(kg·min)-1, and -0.8 ± 13.1% and -1.7 ± 15.4% (P 〉 0.05), respectively. EE and %E for each age-group were, respectively, for men: younger = 1.9 ± 4.1 mL·(kg·min)-1 and 3.8 ± 10.5%, middle-aged = 0.6 ± 3.1 mL.(kg·min)-1 and 0.4 ± 10.3%, older = -0.2 ± 2.7 mL·(kg·min) -1 and -4.2 ± 16.6% (P 〈 0.01); and for women: younger = 1.2 ± 3.1 mL.(kg.min)-1 and 2.7 ±10.0%, middle-aged = 0.7 ± 2.8 mL·(kg·min)-1 and 0.5 ± 11.1%, older = -0.8 ± 2.3 mL-(kg·min)-1 and -9.5 ± 22.4% (P 〈 0.01). Conclusion VO2max were underestimated in younger age-groups and were overestimated in older age groups. Age significantly influences the magnitude of the EE of VO2max in both men and women and should be considered when CRF is estimated using population specific equations, rather than directly measured. 展开更多
关键词 AGING Cardiopulmonary exercise testing Error of measurement
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