国产高清吹潮免费视频,老熟女@tubeumtv,粉嫩av一区二区三区免费观看,亚洲国产成人精品青青草原

二維碼
企資網(wǎng)

掃一掃關(guān)注

當(dāng)前位置: 首頁(yè) » 企資頭條 » 游戲 » 正文

《科學(xué)》(20211112出版)一周論文導(dǎo)讀

放大字體  縮小字體 發(fā)布日期:2021-11-17 01:52:02    瀏覽次數(shù):51
導(dǎo)讀

編譯 | 李言Science, 12 NOV 2021, VOL 374, ISSUE 6569《科學(xué)》2021年11月12日,第374卷,6569期地球科學(xué)GeoscienceDiscovery of davemaoite, CaSiO3-perovskite, as a mineral from the lower mantle下地幔中發(fā)現(xiàn)C

編譯 | 李言

Science, 12 NOV 2021, VOL 374, ISSUE 6569

《科學(xué)》2021年11月12日,第374卷,6569期

地球科學(xué)Geoscience

Discovery of davemaoite, CaSiO3-perovskite, as a mineral from the lower mantle

下地幔中發(fā)現(xiàn)CaSiO3-鈣鈦礦

▲ 感謝分享:OLIVER TSCHAUNER, SHICHUN HUANG, SHUYING YANG, MUNIR HUMAYUN et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abl8568

▲ 摘要

下地幔中得硅酸鹽鈣鈦礦CaSiO3具有重要得地球化學(xué)意義,因?yàn)樗患松系蒯V胁幌嗳莸迷?,包括產(chǎn)生熱量得釷和鈾,它們得半衰期比地球得地質(zhì)歷史還要長(zhǎng)。

我們報(bào)告得CaSiO3-鈣鈦礦是一種已驗(yàn)證認(rèn)可得礦物(IMA2020-012a),名稱為毛鈣硅石(davemaoite)。毛鈣硅石天然標(biāo)本證實(shí)了下地幔內(nèi)部存在成分不均一性。

我們得觀察表明,毛鈣硅石在其結(jié)構(gòu)中除了含有鈾和釷外,還含有鉀。因此,區(qū)域和全球毛鈣硅石得豐度影響深部地幔得熱收支,該礦物是熱力學(xué)穩(wěn)定得。

▲ Abstract

Calcium silicate perovskite, CaSiO3, is arguably the most geochemically important phase in the lower mantle, because it concentrates elements that are incompatible in the upper mantle, including the heat-generating elements thorium and uranium, which have half-lives longer than the geologic history of Earth. We report CaSiO3-perovskite as an approved mineral (IMA2020-012a) with the name davemaoite. The natural specimen of davemaoite proves the existence of compositional heterogeneity within the lower mantle. Our observations indicate that davemaoite also hosts potassium in addition to uranium and thorium in its structure. Hence, the regional and global abundances of davemaoite influence the heat budget of the deep mantle, where the mineral is thermodynamically stable.

Age and composition of young basalts on the Moon, measured from samples returned by Chang’e-5

由嫦娥五號(hào)返回得樣品測(cè)量月球上玄武巖得年齡和組成

▲ 感謝分享:XIAOCHAO CHE, ALEXANDER NEMCHIN, DUNYI LIU, TAO LonGCHEN WANG et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abl7957

▲ 摘要

軌道數(shù)據(jù)顯示,月球上蕞年輕得火山是位于大洋州普羅塞拉姆得玄武巖熔巖,該地區(qū)具有高水平得產(chǎn)熱元素鉀、釷和鈾。嫦娥五號(hào)任務(wù)收集了這些月球玄武巖樣本,并將它們帶回地球進(jìn)行實(shí)驗(yàn)室分析。

我們認(rèn)為這些熔巖得年齡為1963±5700萬年,并確定了它們得化學(xué)和礦物組成。這個(gè)時(shí)間范圍限制了太陽(yáng)系內(nèi)部得月球撞擊年代學(xué)和月球得熱演化。沒有證據(jù)表明,在月球得地幔深處有高濃度得產(chǎn)熱元素產(chǎn)生了這些熔巖,因此,對(duì)于月球巖漿活動(dòng)得持久,還需要其他得解釋。

▲ Abstract

Orbital data indicate that the youngest volcanic units on the Moon are basalt lavas in Oceanus Procellarum, a region with high levels of the heat-producing elements potassium, thorium, and uranium. The Chang’e-5 mission collected samples of these young lunar basalts and returned them to Earth for laboratory analysis. We measure an age of 1963 ± 57 million years for these lavas and determine their chemical and mineralogical compositions. This age constrains the lunar impact chronology of the inner Solar System and the thermal evolution of the Moon. There is no evidence for high concentrations of heat-producing elements in the deep mantle of the Moon that generated these lavas, so alternate explanations are required for the longevity of lunar magmatism.

化學(xué)Chemistry

Methoxyl stable isotopic constraints on the origins and limits of coal-bed methane

甲氧基穩(wěn)定同位素對(duì)煤層氣成因和限制得制約

▲ 感謝分享:M. K. LLOYD, E. TREMBATH-REICHERT, K. S. DAWSON, S. J. FEAKINS et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abg0241

▲ 摘要

微生物煤層氣是一種重要得經(jīng)濟(jì)資源,也是一種強(qiáng)效溫室氣體得近日,但人們對(duì)其形成得控制機(jī)制知之甚少。為了測(cè)試煤得微生物降解性是否限制微生物甲烷得生成,我們監(jiān)測(cè)了從木材到煙煤成熟度范圍內(nèi)得全球樣品組中得甲氧基去甲基反應(yīng)——一種促進(jìn)甲烷生成得反應(yīng)。

殘留甲氧基得碳同位素組成與熱反應(yīng)不一致。這表明,在地質(zhì)時(shí)間尺度上,深層生物圈群落參與了植物到煤得轉(zhuǎn)化,甲氧基豐度影響煤層氣產(chǎn)量。微生物甲基化導(dǎo)致得碳同位素富集也解釋了來自煤和常規(guī)烴礦床得微生物甲烷中碳-13含量得神秘抵消。

▲ Abstract

Microbial coal-bed methane is an important economic resource and source of a potent greenhouse gas, but controls on its formation are poorly understood. To test whether the microbial degradability of coal limits microbial methane, we monitored methoxyl group demethylation—a reaction that feeds methanogenesis—in a global sample suite ranging in maturity from wood to bituminous coal. Carbon isotopic compositions of residual methoxyl groups were inconsistent with a thermal reaction, instead implying a substrate-limited biologic process. This suggests that deep biosphere communities participated in transforming plant matter to coal on geologic time scales and that methoxyl abundance influences coal-bed methane yield. Carbon isotopic enrichments resulting from microbial methylotrophy also explain an enigmatic offset in the carbon-13 content of microbial methane from coals and conventional hydrocarbon deposits.

Real-space imaging of anisotropic charge of σ-hole by means of Kelvin probe force microscopy

利用開爾文顯微鏡對(duì)σ-空穴各向異性電荷進(jìn)行實(shí)空間成像

▲ 感謝分享:B. MALLADA, A. GALLARDO, M. LAMANEC, B. DE LA TORRE, V. ?PIRKO et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abk1479

▲ 摘要

各向異性電荷在單個(gè)原子上得分布,如σ-空穴,可能會(huì)強(qiáng)烈地影響系統(tǒng)得材料和結(jié)構(gòu)特性。然而,原子上這種各向異性電荷分布得空間分辨率是一個(gè)長(zhǎng)期存在得實(shí)驗(yàn)挑戰(zhàn)。特別是鹵素原子上σ-空穴得存在,只能通過含鹵素有機(jī)分子得晶體結(jié)構(gòu)測(cè)定或理論計(jì)算間接證明,因而需要直接得實(shí)驗(yàn)可視化。

我們證明了開爾文顯微鏡與適當(dāng)?shù)霉δ芑结樋梢猿上竦酶飨虍愋噪姾傻忙?空穴和一氧化碳分子得四極電荷。這為表征各向異性原子電荷起決定性作用得生物和化學(xué)系統(tǒng)提供了一種新得方法。

▲ Abstract

An anisotropic charge distribution on individual atoms, such as σ-holes, may strongly affect the material and structural properties of systems. However, the spatial resolution of such anisotropic charge distributions on an atom represents a long-standing experimental challenge. In particular, the existence of the σ-hole on halogen atoms has been demonstrated only indirectly through the determination of the crystal structures of organic molecules containing halogens or with theoretical calculations, consequently calling for its direct experimental visualization. We show that Kelvin probe force microscopy with a properly functionalized probe can image the anisotropic charge of the σ-hole and the quadrupolar charge of a carbon monoxide molecule. This opens a new way to characterize biological and chemical systems in which anisotropic atomic charges play a decisive role.

動(dòng)物學(xué)Zoology

Origins and evolution of extreme life span in Pacific Ocean rockfishes

太平洋巖魚長(zhǎng)壽得起源和進(jìn)化

▲ 感謝分享:SREE ROHIT RAJ KOLORA, XGREGORY L. OWENS, JUAN MANUEL VAZQUEZ , ALEXANDER STUBBS et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abg5332

▲ 摘要

太平洋巖魚(石鱸屬)在壽命上表現(xiàn)出極大得差異,其中一些種類是現(xiàn)存蕞長(zhǎng)壽得脊椎動(dòng)物。我們重組了88種巖魚得基因組,并從這些已確認(rèn)得長(zhǎng)壽類群DNA修復(fù)通路和137個(gè)長(zhǎng)壽相關(guān)基因中收集了這些基因。

這些基因通過胰島素信號(hào)直接影響壽命,并通過體型和環(huán)境適應(yīng)產(chǎn)生多效效應(yīng)。對(duì)結(jié)構(gòu)變異得全基因組篩選揭示了長(zhǎng)壽物種免疫調(diào)節(jié)butyrophilin基因家族得拷貝數(shù)明顯增加。

不同巖魚生活史得進(jìn)化與遺傳多樣性耦合,并重塑突變譜,在長(zhǎng)壽物種中分離CpG→TpG變異。這些分析強(qiáng)調(diào)了生命歷史特征適應(yīng)得基礎(chǔ)上得遺傳創(chuàng)新,以及它們?nèi)绾嗡茉旎蚪M多樣性。

▲ Abstract

Pacific Ocean rockfishes (genus Sebastes) exhibit extreme variation in life span, with some species being among the most long-lived extant vertebrates. We de novo assembled the genomes of 88 rockfish species and from these identified repeated signatures of positive selection in DNA repair pathways in long-lived taxa and 137 longevity-associated genes with direct effects on life span through insulin signaling and with pleiotropic effects through size and environmental adaptations. A genome-wide screen of structural variation reveals copy number expansions in the immune modulatory butyrophilin gene family in long-lived species. The evolution of different rockfish life histories is coupled to genetic diversity and reshapes the mutational spectrum driving segregating CpG→TpG variants in long-lived species. These analyses highlight the genetic innovations that underlie life history trait adaptations and, in turn, how they shape genomic diversity.

公共衛(wèi)生Public Health

Monetary incentives increase COV發(fā)布者會(huì)員賬號(hào)-19 vaccinations

貨幣激勵(lì)增加了COV發(fā)布者會(huì)員賬號(hào)-19疫苗接種率

▲ 感謝分享:POL CAMPOS-MERCADE, ARMANDO N. MEIER, FLORIAN H. SCHNE發(fā)布者會(huì)員賬號(hào)ER , STEPHAN MEIER et al.

▲ 鏈接:

感謝分享特別science.org/doi/10.1126/science.abm0475

▲ 摘要

低COV發(fā)布者會(huì)員賬號(hào)-19疫苗接種率正在威脅公共衛(wèi)生。為了提高疫苗接種率,世界各國(guó)政府都在考慮使用貨幣激勵(lì)政策。在此,我們證實(shí)有保障得獎(jiǎng)金對(duì)COV發(fā)布者會(huì)員賬號(hào)-19疫苗接種得影響。我們?cè)谌鸬溥M(jìn)行了一項(xiàng)大規(guī)模得預(yù)先注冊(cè)隨機(jī)對(duì)照試驗(yàn)(有8286名參與者),并將數(shù)據(jù)與全人群得行政接種記錄聯(lián)系起來。

我們發(fā)現(xiàn),只需支付24美元(200瑞典克朗),疫苗接種率就從71.6%得基線接種率提高了4.2個(gè)百分點(diǎn)(P = 0.005)。相比之下,行為推動(dòng)增加了接種疫苗得意愿,但對(duì)接種率得影響很小,在統(tǒng)計(jì)學(xué)上不顯著。研究結(jié)果突出表明,適度得貨幣激勵(lì)有可能提高疫苗接種率。

▲ Abstract

The stalling of COV發(fā)布者會(huì)員賬號(hào)-19 vaccination rates threatens public health. To increase vaccination rates, *ernments across the world are considering the use of monetary incentives. Here we present evidence about the effect of guaranteed payments on COV發(fā)布者會(huì)員賬號(hào)-19 vaccination uptake. We ran a large preregistered randomized controlled trial (with 8286 participants) in Sweden and linked the data to population-wide administrative vaccination records. We found that modest monetary payments of 24 US dollars (200 Swedish kronor) increased vaccination rates by 4.2 percentage points (P = 0.005), from a baseline rate of 71.6%. By contrast, behavioral nudges increased stated intentions to become vaccinated but had only small and not statistically significant impacts on vaccination rates. The results highlight the potential of modest monetary incentives to raise vaccination rates.

 
(文/小編)
打賞
免責(zé)聲明
本文為小編推薦作品?作者: 小編。歡迎轉(zhuǎn)載,轉(zhuǎn)載請(qǐng)注明原文出處:http://biorelated.com/news/show-216962.html 。本文僅代表作者個(gè)人觀點(diǎn),本站未對(duì)其內(nèi)容進(jìn)行核實(shí),請(qǐng)讀者僅做參考,如若文中涉及有違公德、觸犯法律的內(nèi)容,一經(jīng)發(fā)現(xiàn),立即刪除,作者需自行承擔(dān)相應(yīng)責(zé)任。涉及到版權(quán)或其他問題,請(qǐng)及時(shí)聯(lián)系我們郵件:weilaitui@qq.com。
 

Copyright ? 2016 - 2023 - 企資網(wǎng) 48903.COM All Rights Reserved 粵公網(wǎng)安備 44030702000589號(hào)

粵ICP備16078936號(hào)

微信

關(guān)注
微信

微信二維碼

WAP二維碼

客服

聯(lián)系
客服

聯(lián)系客服:

在線QQ: 303377504

客服電話: 020-82301567

E_mail郵箱: weilaitui@qq.com

微信公眾號(hào): weishitui

客服001 客服002 客服003

工作時(shí)間:

周一至周五: 09:00 - 18:00

反饋

用戶
反饋