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1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

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Biology · 术语表

什么是 Leaf area index？

Definition 3.7 University Biology — Year 1 · 第 3 章 — Functional Organization of a Flowering Plant

The leaf area index $L$ of a plant cover is the total one-sided leaf area per unit area of ground. A meadow in June has $L \approx 3$ , a deciduous forest $4\text{ to }6\,$ , a tropical rain forest up to $8\,$ : several layers of leaf are stacked above every square metre of soil.

Light under a canopy against leaf area index, for three leaf orientations. Beyond L 6 an extra layer of leaves gains almost nothing, which is why canopies stop there. — Light under a canopy against leaf area index, for three leaf orientations. Beyond $L \approx 6$ an extra layer of leaves gains almost nothing, which is why canopies stop there.

示例

Example 3.10 (The oak’s two surfaces)

An oak whose crown shades $100\,\mathrm{m}^{2}$ at $L = 5$ carries $500\,\mathrm{m}^{2}$ of leaf. Its fine roots, at a few kilometres per cubic metre through $100\,\mathrm{m}^{3}$ of soil, offer several hundred square metres, and their root hairs a thousand more: the absorbing surface underground is several times the photosynthetic surface above, over the same square metres of ground.

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