2017-08-18             
巴西最近爆发了70多年来最严重的黄热病疫情，包括有792例确诊病例，其中许多地区一度被认为是安全的。像封面图中展示的黑金色吼猴，就非常容易受到黄热病的影响，并且它们的死亡通常表明疾病已经传播到新的地区。

Brazil recently suffered its worst yellow fever outbreak in more than 70 years, with 792 confirmed cases, many in states once considered safe from the disease. Monkeys, like the black-and-gold howler monkeys (Alouatta caraya) shown here, are especially vulnerable to yellow fever, and their deaths often serve as a warning that the disease is spreading to new areas.

      2017-08-25    
封面上展示的是一个来自坦桑尼亚的哈德扎采猎者手中拿着的一块蜂巢。这些人的微生物群落与人类祖先的微生物群落近似，遵循了一种能够反映出他们饮食季节性的循环模式。在这些季节性变化中，最具活力的微生物谱系在工业化人口中很少见或者是根本无法检测到的。

A Hadza hunter-gatherer from Tanzania holding a piece of honeycomb. The microbiome of these people, which serves as an approximation of humanity's ancestral microbiome, follows a cyclic pattern that mirrors the seasonality of their diet. The most dynamic microbial lineages across these seasonal shifts are among those that are rare or undetectable in industrialized populations.

     2017-09-01     
封面图展示的是一个女人的手抓着一片巨大的龟背竹叶，这是一种原产于美国热带地区的常见植物。植物叶片的大小会因空气温度、光线及土壤湿度的不同而具有很大差异，这可能会影响到叶片在白天过热或在晚上遭受霜冻的可能性。因此，在炎热的沙漠和寒冷的高海拔地区生长的物种其特征通常是叶片较小，而生长在温暖的热带雨林中的植物则具有较大的叶片。

A woman grips a giant Monstera leaf, a common plant genus of the American tropics. Leaf size varies enormously with differences in air temperature, light, and soil moisture, which affect the possibility of leaves overheating during the day or suffering frost damage at night. Thus, hot deserts and cold high-elevation sites are characterized by small-leaved species, whereas plants in warm rainforests tend to have larger leaves.

     2017-09-08    
封面上展示的是通过艺术手法描绘的将超冷原子（封面上与原子轨道共同展示；蓝色和红色部分分别代表凝固或易变的内部状态）加载到一个光学晶格中，用来模拟固体中电子所经历的周期性环境。通过探测原子和分子在冷却到非常低的温度时的状态，就可以找出物理学和化学中一些最有趣的问题的答案。

Artistic depiction of ultracold atoms (shown with atomic orbitals; blue/red indicate frozen/mobile internal states) loaded into an optical lattice, which mimics the periodic environment experienced by electrons in solids. Probing atoms and molecules cooled to very low temperatures can tease out answers to some of the most intriguing questions in physics and chemistry.
（陶 陶　编译）■