Indeed,volatile food prices, population growth, low agricultural productivity and the potentially devastating effects of climate change make it a particularly daunting challenge. The IFAD president says over the past 30 years, agricultural productivity in developing countries has been stagnant or in decline. He blames it on years of under-investment.

VOA: standard.2010.03.29

So these names, they don't really make any sense why they're called past s p and f, and it turns out that it comes from spectroscopy terms that are pre-quantum mechanics where, for example, this is called the sharp line, I think the principle, the diffuse, and the fundamental.

看到这些名字，你会发现,它们为什么叫s，p，f是没什么道理的，事实上,它们来源于,量子力学之前的光谱学中的术语，例如，它们分别叫做锐线，我认为是主线，漫射和基本。

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