編譯 | 李言
Science, 9 February 2024, Volume 383 Issue 6683
《科學》2024年2月9日，第383卷，6683期
醫(yī)學Medicine
What drives poor quality of care for child diarrhea? Experimental evidence from India
什么導致兒童腹瀉護理質量差？來自印度的實驗證據
▲ 作者：
ZACHARY WAGNER, MANOJ MOHANAN et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adj9986
▲ 摘要：
發(fā)展中國家的大多數衛(wèi)生保健提供者都知道口服補液鹽（ORS）是一種可以挽救生命且價格低廉的兒童腹瀉治療方法，但很少有人開這種藥。
這種“知—行”差距困擾了專家們幾十年。通過在印度進行的隨機實驗，我們預估ORS處方不足的程度是由患者不需要口服補液藥物的認知、提供者的財務激勵和口服補液藥物缺貨（缺貨事件）共同驅動的。
偏愛ORS的患者將ORS處方率增加了27%。減少缺貨情況使ORS處方率增加了7%。取消財政激勵并不影響ORS療法的處方，但確實增加了藥店的ORS療法處方。我們估計，42%的少開處方是由于患者不想要ORS，而缺貨和財務激勵分別只解釋了另外6%和5%的情況。
▲ 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.
化學Chemistry
Differentiating enantiomers by directional rotation of ions in a mass spectrometer
用質譜儀中離子的定向旋轉來區(qū)分對映體
▲ 作者：XIAOYU ZHOU, ZHUOFAN WANG et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adj8342
▲ 摘要：
在此，我們報告一種通過誘導手性氣相離子的定向旋轉來打破手性對稱并區(qū)分對映體的技術。我們采用雙交流激勵來控制捕獲離子的運動，包括圍繞質量中心的旋轉和圍繞陷阱中心的宏觀運動。
碰撞截面的差異可以通過10000以上高分辨率的離子云剖面來測量。采用微型離子阱質譜儀，我們將高場離子遷移率與串聯質譜分析相結合，實現了對映體的分析。
▲ 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.
地質學Geology
A deep reservoir for hydrogen drives intense degassing in the Bulqizë ophiolite
深層儲氫層驅動Bulqizë蛇綠巖的強烈脫氣
▲ 作者：LAURENT TRUCHE, FRéDéRIC-VICTOR DONZé et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adk9099
▲ 摘要：
我們報告了在阿爾巴尼亞的地下深部Bulqizë鉻鐵礦中直接測量到的H2的高放氣率84%。每年至少有200噸氫氣從該礦礦道中排出，使其成為迄今最大的氫氣流量記錄之一。
我們不能把這種通量完全歸因于被困在巖石中的古流體的釋放，也不能將其歸因于現今活躍而普遍的超鎂質巖石蛇紋石化；相反，我們的結果表明，在侏羅紀蛇綠巖地塊中存在一個斷裂的儲層。這一發(fā)現表明，這些蛇綠巖里可能蘊藏著有經濟效益的氫氣。
▲ 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
強相互作用費米氣體中超流體躍遷的熱成像
▲ 作者：ZHENJIE YAN, PARTH B. PATEL et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adg3430
▲ 摘要：
在這項研究中，我們建立了強相互作用原子費米氣體的熱成像，其射頻頻譜提供了亞納米開爾文分辨率的空間分辨溫度測量。超流體相變直接表現為從熱擴散到二次聲傳播的突然轉變，同時伴有二次聲擴散系數的峰值。
這種方法產生了強相互作用費米氣體的熱量和密度響應，從而定義了朗道雙流體流體力學的所有性質。
▲ 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.
生態(tài)學Ecology
Escarpment evolution drives the diversification of the Madagascar flora
懸崖進化推動了馬達加斯加植物群的多樣化
▲ 作者：YI LIU, YANYAN WANG et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adi0833
▲ 摘要：
馬達加斯加具有高度的、過去數千萬年里以持續(xù)穩(wěn)定的物種形成率進化的地方性生物多樣性。馬達加斯加的地形主要是一個多山的大陸裂谷懸崖，在這個地理特征陡峭的東側發(fā)現了最高的植物多樣性和稀有性。
通過一個模型，我們發(fā)現降水驅動的侵蝕和高起伏地形的向陸退縮通過多種機制創(chuàng)造了短暫的棲息地組織，包括流域擴張、高地的隔離和地形屏障的形成。在百萬年的時間尺度上，棲息地的隔離和重新連接作為異域物種形成的泵，創(chuàng)造了我們所觀察到的生物多樣性。
▲ 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.
生物學Biology
Plants distinguish different photoperiods to independently control seasonal flowering and growth
植物區(qū)分不同的光周期，獨立控制季節(jié)開花和生長
▲ 作者：QINGQING WANG, WEI LIU et al.
▲ 鏈接：
https://www.science.org/doi/10.1126/science.adg9196
▲ 摘要：
通過利用一個具有光周期生長缺陷的突變體，我們確定了一種與典型的長日光周期開花機制平行的長日季節(jié)性生長調節(jié)途徑。
這是通過使用不一樣的機制來檢測不同的光周期來實現的：開花機制將光周期定為光強度的持續(xù)時間，而生長機制將光周期測量為光合活動的持續(xù)時間（光合期）。
因此植物可以獨立控制開花或生長所需基因的表達。這表明季節(jié)性開花和生長是可分離的，這使得它們得以在季節(jié)之間獨立協調。
▲ 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.
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