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编译 | 李言

Science, 9 February 2024, Volume 383 Issue 6683

《科学》2024年2月9日，第383卷，6683期

医学Medicine

What drives poor quality of care for child diarrhea? Experimental evidence from India

什么导致儿童腹泻护理质量差？来自印度的实验证据

▲ 作者：

ZACHARY WAGNER, MANOJ MOHANAN et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adj9986

▲ 摘要：

发展中国家的大多数卫生保健提供者都知道口服补液盐（ORS）是一种可以挽救生命且价格低廉的儿童腹泻治疗方法，但很少有人开这种药。

这种“知—行”差距困扰了专家们几十年。通过在印度进行的随机实验，我们预估ORS处方不足的程度是由患者不需要口服补液药物的认知、提供者的财务激励和口服补液药物缺货（缺货事件）共同驱动的。

偏爱ORS的患者将ORS处方率增加了27%。减少缺货情况使ORS处方率增加了7%。取消财政激励并不影响ORS疗法的处方，但确实增加了药店的ORS疗法处方。我们估计，42%的少开处方是由于患者不想要ORS，而缺货和财务激励分别只解释了另外6%和5%的情况。

▲ Abstract：

Most health care providers in developing countries know that oral rehydration salts (ORS) are a lifesaving and inexpensive treatment for child diarrhea, yet few prescribe it. This know-do gap has puzzled experts for decades. Using randomized experiments in India, we estimated the extent to which ORS underprescription is driven by perceptions that patients do not want ORS, provider’s financial incentives, and ORS stock-outs (out-of-stock events). Patients expressing a preference for ORS increased ORS prescribing by 27 percentage points. Eliminating stock-outs increased ORS provision by 7 percentage points. Removing financial incentives did not affect ORS prescribing on average but did increase ORS prescribing at pharmacies. We estimate that perceptions that patients do not want ORS explain 42% of underprescribing, whereas stock-outs and financial incentives explain only 6 and 5%, respectively.

化学Chemistry

Differentiating enantiomers by directional rotation of ions in a mass spectrometer

用质谱仪中离子的定向旋转来区分对映体

▲ 作者：XIAOYU ZHOU, ZHUOFAN WANG et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adj8342

▲ 摘要：

在此，我们报告一种通过诱导手性气相离子的定向旋转来打破手性对称并区分对映体的技术。我们采用双交流激励来控制捕获离子的运动，包括围绕质量中心的旋转和围绕陷阱中心的宏观运动。

碰撞截面的差异可以通过10000以上高分辨率的离子云剖面来测量。采用微型离子阱质谱仪，我们将高场离子迁移率与串联质谱分析相结合，实现了对映体的分析。

▲ Abstract：

Here we report a technique to break the chiral symmetry and to differentiate enantiomers by inducing directional rotation of chiral gas-phase ions. Dual alternating current excitations were applied to manipulate the motions of trapped ions, including the rotation around the center of mass and macro movement around the center of the trap. Differences in collision cross section were induced, which could be measured by ion cloud profiling at high resolutions above 10,000. High-field ion mobility and tandem mass spectrometry analyses of the enantiomers were combined and implemented by using a miniature ion trap mass spectrometer.

地质学Geology

A deep reservoir for hydrogen drives intense degassing in the Bulqizë ophiolite

深层储氢层驱动Bulqizë蛇绿岩的强烈脱气

▲ 作者：LAURENT TRUCHE, FRéDéRIC-VICTOR DONZé et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adk9099

▲ 摘要：

我们报告了在阿尔巴尼亚的地下深部Bulqizë铬铁矿中直接测量到的H₂的高放气率84%。每年至少有200吨氢气从该矿矿道中排出，使其成为迄今最大的氢气流量记录之一。

我们不能把这种通量完全归因于被困在岩石中的古流体的释放，也不能将其归因于现今活跃而普遍的超镁质岩石蛇纹石化；相反，我们的结果表明，在侏罗纪蛇绿岩地块中存在一个断裂的储层。这一发现表明，这些蛇绿岩里可能蕴藏着有经济效益的氢气。

▲ Abstract：

We report direct measurements of an elevated outgassing rate of 84% (by volume) of H₂ from the deep underground Bulqizë chromite mine in Albania. A minimum of 200 tons of H₂ is vented annually from the mine’s galleries, making it one of the largest recorded H₂ flow rates to date. We cannot attribute the flux solely to the release of paleo-fluids trapped within the rocks or to present-day active and pervasive serpentinization of ultramafic rocks; rather, our results demonstrate the presence of a faulted reservoir deeply rooted in the Jurassic ophiolite massif. This discovery suggests that certain ophiolites may host economically useful accumulations of H₂ gas.

物理Physics

Thermography of the superfluid transition in a strongly interacting Fermi gas

强相互作用费米气体中超流体跃迁的热成像

▲ 作者：ZHENJIE YAN, PARTH B. PATEL et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adg3430

▲ 摘要：

在这项研究中，我们建立了强相互作用原子费米气体的热成像，其射频频谱提供了亚纳米开尔文分辨率的空间分辨温度测量。超流体相变直接表现为从热扩散到二次声传播的突然转变，同时伴有二次声扩散系数的峰值。

这种方法产生了强相互作用费米气体的热量和密度响应，从而定义了朗道双流体流体力学的所有性质。

▲ Abstract：

In this study, we establish thermography of a strongly interacting atomic Fermi gas, whose radio-frequency spectrum provides spatially resolved thermometry with subnanokelvin resolution. The superfluid phase transition was directly observed as the sudden change from thermal diffusion to second-sound propagation and is accompanied by a peak in the second-sound diffusivity. This method yields the full heat and density response of the strongly interacting Fermi gas and therefore all defining properties of Landau’s two-fluid hydrodynamics.

生态学Ecology

Escarpment evolution drives the diversification of the Madagascar flora

悬崖进化推动了马达加斯加植物群的多样化

▲ 作者：YI LIU, YANYAN WANG et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adi0833

▲ 摘要：

马达加斯加具有高度的、过去数千万年里以持续稳定的物种形成率进化的地方性生物多样性。马达加斯加的地形主要是一个多山的大陆裂谷悬崖，在这个地理特征陡峭的东侧发现了最高的植物多样性和稀有性。

通过一个模型，我们发现降水驱动的侵蚀和高起伏地形的向陆退缩通过多种机制创造了短暂的栖息地组织，包括流域扩张、高地的隔离和地形屏障的形成。在百万年的时间尺度上，栖息地的隔离和重新连接作为异域物种形成的泵，创造了我们所观察到的生物多样性。

▲ Abstract：

Madagascar exhibits high endemic biodiversity that has evolved with sustained and stable rates of speciation over the past several tens of millions of years. The topography of Madagascar is dominated by a mountainous continental rift escarpment, with the highest plant diversity and rarity found along the steep, eastern side of this geographic feature. Using a process-explicit model, we show that precipitation-driven erosion and landward retreat of this high-relief topography creates transient habitat organization through multiple mechanisms, including catchment expansion, isolation of highland remnants, and formation of topographic barriers. Habitat isolation and reconnection on a million-year timescale serves as an allopatric speciation pump creating the observed biodiversity.

生物学Biology

Plants distinguish different photoperiods to independently control seasonal flowering and growth

植物区分不同的光周期，独立控制季节开花和生长

▲ 作者：QINGQING WANG, WEI LIU et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adg9196

▲ 摘要：

通过利用一个具有光周期生长缺陷的突变体，我们确定了一种与典型的长日光周期开花机制平行的长日季节性生长调节途径。

这是通过使用不一样的机制来检测不同的光周期来实现的：开花机制将光周期定为光强度的持续时间，而生长机制将光周期测量为光合活动的持续时间（光合期）。

因此植物可以独立控制开花或生长所需基因的表达。这表明季节性开花和生长是可分离的，这使得它们得以在季节之间独立协调。

▲ Abstract：

By using a mutant with defects in photoperiodic growth, we identified a seasonal growth regulation pathway that functions in long days in parallel to the canonical long-day photoperiod flowering mechanism. This is achieved by using distinct mechanisms to detect different photoperiods: The flowering pathway measures photoperiod as the duration of light intensity, whereas the growth pathway measures photoperiod as the duration of photosynthetic activity (photosynthetic period). Plants can then independently control expression of genes required for flowering or growth. This demonstrates that seasonal flowering and growth are dissociable, allowing them to be coordinated independently across seasons.