Analysis of entropies based on empirical mode decomposition in amnesic mild cognitive impairment of diabetes mellitus

EEG characteristics that correlate with the cognitive functions are important in detecting mild cognitive impairment(MCI)in T2DM.To investigate the complexity between aMCI group and age-matched non-aMCI control group in T2DM,six entropies combining empirical mode decomposition(EMD),including Approximate entropy(ApEn),Sample entropy(SaEn),Fuzzy entropy(FEn),Permutation entropy(PEn),Power spectrum entropy(PsEn)and Wavelet entropy(WEn)were used in the study.A feature extraction technique based on maximization of the area under the curve(AUC)and a support vector machine(SVM)were subsequently used to for features selection and classi¯cation.Finally,Pearson's linear correlation was employed to study associations between these entropies and cognitive functions.Compared to other entropies,FEn had a higher classification accuracy,sensitivity and specificity of 68%,67.1% and 71.9%,respectively.Top 43 salient features achieved classification accuracy,sensitivity and speci¯city of 73.8%,72.3% and 77.9%,respectively.P4,T4 and C4 were the highest ranking salient electrodes.Correlation analysis showed that FEn based on EMD was positively correlated to memory at electrodes F7,F8 and P4,and PsEn based on EMD was positively correlated to Montreal cognitive assessment(MoCA)and memory at electrode T4.In sum,FEn based on EMD in righttemporal and occipital regions may be more suitable for early diagnosis of the MCI with T2DM.

早寒武纪清江丝菌牵出硫酸盐还原菌与地球环境协同演化 历史

Sulfate reduction is an essential metabolism that maintains biogeochemical cycles in marine and terrestrial ecosystems.Sulfate reducers are exclusively prokaryotic,phylogenetically diverse,and may have evolved early in Earth’s history.However,their origin is elusive and unequivocal fossils are lacking.Here we report a new microfossil,Qingjiangonema cambria,from518-million-year-old black shales that yield the Qingjiang biota.Qingjiangonema is a long filamentous form comprising hundreds of cells filled by equimorphic and equidimensional pyrite microcrystals with a light sulfur isotope composition.Multiple lines of evidence indicate Qingjiangonema was a sulfate-reducing bacterium that exhibits similar patterns of cell organization to filamentous forms within the phylum Desulfobacterota,including the sulfate-reducing Desulfonema and sulfide-oxidizing cable bacteria.Phylogenomic analyses confirm separate,independent origins of multicellularity in Desulfonema and in cable bacteria.Molecular clock analyses infer that the Desulfobacterota,which encompass a majority of sulfate-reducing taxa,diverged~2.41 billion years ago during the Paleoproterozoic Great Oxygenation Event,while cable bacteria diverged~0.56 billion years ago during or immediately after the Neoproterozoic Oxygenation Event.Taken together,we interpret Qingjiangonema as a multicellular sulfate-reducing microfossil and propose that cable bacteria evolved from a multicellular filamentous sulfate-reducing ancestor.We infer that the diversification of the Desulfobacterota and the origin of cable bacteria may have been responses to oxygenation events in Earth’s history.

Multiple thermal events recorded in the Acasta Gneiss Complex:Evidence from in-situ dating of zircon, titanite, and apatite

In-situ dating of the zircons, titanites, and apatites in the rock fragments of approximately 1 cm2in size from the Acasta Gneiss Complex was performed using secondary ion mass spectrometry or laser ablation inductively coupled plasma mass spectrometry to provide constraints on the thermal history of the Acasta Gneiss Complex. The zircons in these rock fragments typically exhibit multiple age populations, reflecting the presence of inherited zircons or the post-crystallization process of zircon overgrowth. Combined with previous studies, our zircon dating results reveal multiple magmatic events that occurred in the Acasta Gneiss Complex, specifically at >3.96, ~3.72, and ~3.57 Ga, respectively. A titanite Pb-Pb isochron age of2911±22 Ma(95% confidence level, MSWD=1.5) for sample AY199 is identified, consistent with the timing of the latest Archean magmatism in the Acasta Gneiss Complex. The titanite U-Pb ages for samples AC478 and AY066 are 1932±270 Ma(95% confidence level, MSWD=2.3) and 1813±45 Ma(95% confidence level, MSWD=2.3), respectively. The apatites in sample P090803-C exhibit a Pb-Pb isochron age of 1833±26 Ma(95% confidence level, MSWD=1.4). The apatite U-Pb ages for samples AC478, AY199, and AY066 are 1850±20 Ma(95% confidence level, MSWD=1.3), 1827±100 Ma(95% confidence level, MSWD=6.3), and 1807±58 Ma(95% confidence level, MSWD=3.9), respectively. Titanites in samples AC478 and AY066, as well as the apatites in all four investigated samples, show a uniform age(Pb-Pb or U-Pb age) of ~1.9–1.8 Ga,indicating U-Pb system reset in these minerals due to the Wopmay orogeny and documenting that the peak temperature condition associated with the Wopmay orogeny exceeded the apatite U-Pb closure temperature and approached or exceeded that of titanite.

Long-Term Reproducibility of SIMS Zircon U-Pb Geochronology

Secondary ion mass spectrometry(SIMS) zircon U-Pb dating has been widely used to confine the absolute ages of the magmatic or metamorphic events and to distinguish multiple events.Here,a data set consisting of the zircon standards dating data(~15 000 Ple?ovice and ~8 000 Qinghu items) accumulated for more than 8 years using the CAMECA IMS 1280 HR of the Institute of Geology and Geophysics,Chinese Academy of Sciences(IGGCAS) is compiled to evaluate the long-term external reproducibility.With Ple?ovice zircon as the calibration standard and Qinghu zircon as an unknown sample,the analytical uncertainties for single-spot(n = 7 723) and session analyses(n = 691,with more than 7 single spot analyses in one session) are 2.6% and 0.9%(2 RSD,relative standard deviation),respectively.It means that single-spot U-Pb dating for a standard-level zircon sample could vary 5.2% at 95% confidence level,while the average value(n > 7) for each session may vary 1.8%.Thus,these values should be considered as the minimum uncertainty when comparing single spot and individual session analysis results for multiple dating works on a certain geological event.

Chang’e-5 samples reveal two-billion-year-old volcanic activity on the Moon and its source characteristics

The Chang’e-5 mission returned new lunar samples after the last sample mission of the Moon 44 years ago,and is also the first mission that China has completed the sampling of extraterrestrial bodies.Recently,independent teams from the Institute of Geology,Chinese Academy of Geological Sciences,and the National Astronomical Observatories and the Institute of Geology and Geophysics,Chinese Academy of Sciences reported the first batch of results of Chang’e-5 lunar samples.The basic physical properties of the Chang’e-5 soil are within the range of the Apollo and Luna samples though the Chang’e-5 soil is finer-grained,better sorted,and has a slightly lower true density than the mare basalt previosuly reported.The Pb-Pb dating of U-rich minerals in the Chang’e-5 basalt clasts indicated that they formed at about 2.0 Ga,800 million years younger than the youngest lunar sample recovered previously(2.8 Ga),confirming that lunar volcanic activity can last at least until 2 Ga.In-situ Sr-Nd isotope analyses suggested that the Chang’e-5 basalt originated from a depleted mantle source.The contribution of the KREEP component is less than 5%,which excluded the hypothesis that KREEP-rich sources provide an additional heat source for mantle melting.In addition,water contents and H isotopes of apatite and melt inclusions of the Chang’e-5 basalt suggested that the source region is not rich in water which can lower the melting point.Therefore,the reason why lunar volcanic activity can last so long is still unclear,which is a new direction for future lunar exploration and research.

Decoupling between Oxygen and Radiogenic Isotopes: Evidence for Generation of Juvenile Continental Crust by Partial Melting of Subducted Oceanic Crust

There is increasing evidence indicating that melts derived from subducted oceanic crust and sediments may have played a key role in building continental crust. This mechanism predicts that juvenile arc crust should have oxygen isotope characteristics ranging from mantle-like to supracrustal, but consistent mantle-like radiogenic(Nd-Hf) isotopic signatures. Here we present in-situ zircon U-Pb dating, Hf-O isotope analyses, and whole rock major-trace element and Nd isotope analyses of a granitoid from NW India. In-situ secondary ion mass spectrometry(SIMS) zircon U-Pb dating yields a weighted mean ^(207)Pb/^(206)Pb age of 873±6 Ma for the granitoid. It displays mantle-like zircon εHf(εHf(873 Ma)= +9.3 to +10.9) and whole-rock Nd(εNd(873 Ma)= +3.5) values but supracrustal δ^(18)O values, the latter mostly varying between 9‰ and 10‰. The calculated whole-rock δ^(18)O value of 11.3‰±0.6‰ matches well with those of hydrothermally-altered pillow lavas and sheeted dykes from ophiolites. The major and trace element composition of the granitoid is similar to petrological experimental melts derived from a mixture of MORB+sediments. Thus, the granitoid most likely represents the product of partial melting of the uppermost oceanic crust(MORB+sediments). We propose that the decoupling between Hf-Nd and O isotopes as observed in this granitoid can be used as a powerful tool for the identification of slab melting contributing to juvenile continental crustal growth. Such isotopic decoupling can also account for high δ^(18)O values observed in ancient juvenile continental crust, such as Archean tonalitetrondhjemite-granodiorite suites.

太古宙科马提岩并非来自^(18)O亏损的地幔源区

氧是地幔中丰度最高的元素,探究地球早期原始地幔的氧同位素组成对了解硅酸盐地球的起始特征以及后期分异过程极为重要.太古宙早期的科马提岩多源自地球深部很少受到后期对流扰动的地幔源区,因此是揭示地球早期地幔属性的绝佳对象.前人基于激光氟化法对科马提岩中橄榄石的氧同位素分析提出地球早期深部地幔存在一个异常亏损^(18)O的源区.本文通过详细的显微结构和微区氧同位素分析揭示所谓异常亏损^(18)O的特征更可能是激光氟化分析过程中混入次生矿物蛇纹石和磁铁矿的结果.岩浆成因橄榄石具有与现今地幔橄榄石一致的氧同位素组成.这表明原始地幔并不存在初始的氧同位素不均一性且该特征自冥古宙以来未发生明显变化.因此,地幔中出现富集或亏损^(18)O的组分可归因于表壳物质再循环,这对于识别板块构造启动时间以及幔源岩浆成因具有重要意义.

Insights into the origin of purely sediment-derived Himalayan leucogranites:Si-O isotopic constraints

Granite is the dominant rock type in Earth’s continental crust.The origin of granite can be directly or indirectly related to the fractional crystallization of mantle-derived basaltic melt or the reworking of pre-existing continental or oceanic crust, which contribute to the growth of continental crust. Among the various types of granites, the peraluminous leucogranites in the Himalayan orogen, which are high in SiO_2(>73%) and low in mafic minerals (<5%),

松科2井东孔沙河子组离子探针锆石U-Pb定年

The Songliao Basin,northeastern China(Fig.1a),is one of the largest non-marine petroliferous basins in the world and contains a nearly complete Cretaceous terrestrial sedimentary sequences.This succession provides vital information that can improve our knowledge of a series of important geodynamical,geological,and paleoenvironmental events[1,2].The lower Cretaceous Shahezi Formation,which is the main source rock strata in the basin,formed during the rifting stage of the basin and consists of gray to black lacustrine and floodplain mudstones and siltstones interbedded with gray sandstones and conglomerates.The unit overlies the Huoshiling Formation and is overlain by the Yingcheng Formation(Fig.1b).

Zircon Xenocrysts from the Shaka Ridge Record Ancient Continental Crust:New U-Pb Geochronological and Oxygen Isotopic Data

Over the past two decades, a significant number of discoveries of ancient zircon xenocrysts in ocean-floor magmatic rocks have been reported. These findings provide compelling evidence for the presence of ancient continental crust within young oceanic lithosphere. Almost all finds of ancient zircon xenocrysts within oceanic crust are from the Mid-Atlantic Ridge. For other localities, however, similar data are very limited. This report presents the first age determinations(U-Pb, SHRIMPII) and isotope-geochemical data(oxygen, trace and rare earth elements) for zircon xenocrysts from gabbro-diorites of the Shaka Ridge, in the vicinity of the Shaka fracture zone, near the western end of the Southwest Indian Ridge. The work is based on a study of bottom rock material dredged during expeditionary research on the R/V"Akademik Fedorov"(Russia) in 2016. The U-Pb isotope system of the zircon xenocrysts recorded a crystallization age of ~2.8 Ga at an upper discordia intercept and an age of ~600 Ma interpreted as the timing of a superimposed thermal event at a lower discordia intercept.The zircon xenocrysts show geochemical signatures of magmatic origin, i.e., fractionated REE distribution spectra with an increase in chondrite-normalized values from light to heavy REE, positive Ce anomalies and negative Eu anomalies, and high Th/U ratios(0.59-7.77). In discrimination diagrams based on a series of inter-element relationships, zircon compositions fall into the fields of zircons from rocks of continental crust, mostly granitoids. The Li content of the zircons is high(1.8 ppm-50 ppm),adding further evidence to their derivation from rocks of continental crust. During their residence within young oceanic crust, the zircon xenocrysts experienced alterations under the influence of submarine high-temperature hydrothermal fluids, which selectively affected the distribution of trace elements in the zircons and reduced the δ;O values to 1.75‰-3.15‰. The presence of obviously older zircons in Shaka gabbro-diorites clearly demonstrates the presence of ancient continental fragments and their recycling into the mantle at the western end of the Southwest Indian Ridge.

陆生蜗牛壳体日分辨率氧同位记录定量重建"千年一遇"超级暴雨

A"once-in-a-millennium"super rainstorm battered Zhengzhou,central China,from 07/17/2021 to 07/22/2021(named"7.20"Zhengzhou rainstorm).It killed 398 people and caused billions of dollars in damage.A pressing question is whether rainstorms of this intensity can be effectively documented by geological archives to understand better their historical variabilities beyond the range of meteorological data.Here,four land snail shells were collected from Zhengzhou,and weekly to daily resolved snail shellδ^(18)O records from June to September of 2021 were obtained by gas-source mass spectrometry and secondary ion mass spectrometry.The daily resolved records show a dramatic negative shift between 06/18/2021 and 09/18/2021,which has been attributed to the"7.20"Zhengzhou rainstorm.Moreover,the measured amplitude of this shift is consistent with the theoretical value estimated from the flux balance model and instrumental data for the"7.20"Zhengzhou rainstorm.Our results suggest that the ultra-high resolutionδ^(18)O of land snail shells have the potential to reconstruct local synoptic scale rainstorms quantitatively,and thus fossil snail shells in sedimentary strata can be valuable material for investigating the historical variability of local rainstorms under different climate backgrounds.