The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

Conodont Caudicriodus woschimidti woschmidti has been found from a big outcrop (hill) of the Bayan-Kho-shuu Ruins Section which was previously assigned to the Silurian Gavuu Member of the Mandalovoo Formation. This is first time to find the lowermost Devonian conodont zonal fossil in Mongolia. The lower part of the Gavuu Member is Sil-urian. But the strata from where we collected samples M-9～M-12 definitely belong to Lower Devonian (lower Lochko-vian) rather than Lower Silurian. The Mandalovoo Formation should be named Mandalovoo Group, and its three mem-bers should be changed into three formations.

Late Ordovician and Early Devonian conodonts from Onoo Tolgoi area of Mongolia

Conodont samples were collected from three localities in the Onoo Tolgoi area,Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation (M288-M294) lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation (M295-M299) contain Ozarkodina pandora alpha Morph. (P element), clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities(M300-M303) yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf.baotaensis, Eoplacognathus jianyeensis, Eoplacognathus protoramosus; Baltoniodus alobatus; and ?Ambalodus triangularis; the age is Late Ordovician,more precisely, early-middle Late Ordovician.

Age of Berh Hairhan Formation of Mongolia dated by conodonts

Conodont Caudicriodus angustus angustus(Steward et al.,1956) and Caudicriodus angustus cauda(Wang et al.,2005) were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to Ulaanbaatar City.The discovery indicates that the Berh Haihan Formation should be assigned to Middle Devonian Eifelian Stage.This conodont fauna was from a shallow cooler water facies in the relatively high latitude.

Heteromerization of short-chain trans-prenyltransferase controls precursor allocation within a plastidial terpenoid network

Terpenes are the largest and most diverse class of plant specialized metabolites.Sesterterpenes(C25),which are derived from the plastid methylerythritol phosphate pathway,were recently characterized in plants.In Arabidopsis thaliana,four genes encoding geranylfarnesyl diphosphate synthase(GFPPS)(AtGFPPS1 to 4)are responsible for the production of GFPP,which is the common precursor for sesterterpene biosynthesis.However,the interplay between sesterterpenes and other known terpenes remain elusive.Here,we first provide genetic evidence to demonstrate that GFPPSs are responsible for sesterterpene production in Arabidopsis.Blockage of the sesterterpene pathway at the GFPPS step increased the production of geranylgeranyl diphosphate(GGPP)-derived terpenes.Interestingly,co-expression of sester TPSs in GFPPSOE(overexpression)plants rescued the phenotypic changes of GFPPS-OE plants by restoring the endogenous GGPP.We further demonstrated that,in addition to precursor(DMAPP/IPP)competition by GFPPS and GGPP synthase(GGPPS)in plastids,GFPPS directly decreased the activity of GGPPS through protein-protein interaction,ultimately leading to GGPP deficiency in planta.Our study provides a new regulatory mechanism of the plastidial terpenoid network in plant cells.

A recently evolved BAHD acetyltransferase,responsible for bitter soyasaponin A production,is indispensable for soybean seed germination

Soyasaponins are major small molecules that accumulate in soybean(Glycine max)seeds.Among them,type-A soyasaponins,fully acetylated at the terminal sugar of their C22 sugar chain,are responsible for the bitter taste of soybean-derived foods.However,the molecular basis for the acetylation of type-A soyasaponins remains unclear.Here,we identify and characterize Gm SSAc T1,encoding a BADH-type soyasaponin acetyltransferase that catalyzes three or four consecutive acetylations on type-A soyasaponins in vitro and in planta.Phylogenetic analysis and biochemical assays suggest that Gm SSAc T1 likely evolved from acyltransferases present in leguminous plants involved in isoflavonoid acylation.Loss-of-function mutants of Gm SSAc T1 exhibited impaired seed germination,which attribute to the excessive accumulation of null-acetylated type-A soyasaponins.We conclude that Gm SSAc T1 not only functions as a detoxification gene for high accumulation of type-A soyasaponins in soybean seeds but is also a promising target for breeding new soybean varieties with lower bitter soyasaponin content.

Shape-preserving storage of elegant Ince-Gaussian modes in warm atomic vapor

Multimode photonic quantum memory could enhance the information processing speed in a quantum repeater-based quantum network. A large obstacle that impedes the storage of the spatial multimode in a hot atomic ensemble is atomic diffusion, which severely disturbs the structure of the retrieved light field. In this paper, we demonstrate that the elegant InceGaussian(eIG) mode possesses the ability to resist such diffusion. Our experimental results show that the overall structure of the eIG modes under different parameters maintains well after microseconds of storage. In contrast, the standard IG modes under the same circumstance are disrupted and become unrecognizable. Our findings could promote the construction of quantum networks based on room-temperature atoms.

Age of the Silurian Lower Red Beds in South China:Stratigraphical Evidence from the Sanbaiti Section

The age of the Silurian Lower Red Beds in the Upper Yangtze region remains debatable.Twenty-four samples were collected for conodont biostratigraphical studies from the Paiyunan Formation in the Sanbaiti Section,Huaying,Sichuan Province.The conodont fauna from the Paiyunan Formation,together with the graptolites from the underlying Lungmachi Formation,indicates that the Lower Red Beds at Sanbaiti correspond to the lower Telychian.Comparative analysis indicates that most exposures of the Lower Red Beds in the Upper Yangtze region can be assigned,in general,to the Telychian Stage,except for several localities,where the Lower Red Beds can be roughly dated as an interval between the upper Aeronian and lower Telychian.

EFFECTS OF SI, N AND B DOPING ON THE MECHANICAL PROPERTIES OF GRAPHENE SHEETS

Molecular dynamics （MD） simulations were performed to stretch the rectangular graphene sheets doped with silicon, nitrogen or boron atoms. Young＇s modulus, ultimate stress （strain） and energy absorption were measured for the graphene sheets with the doping concentration （DC） ranging from 0 to 5%. The emphasis was placed on the distinct effects of each individual dopant on the fundamental mechanical properties of graphene. The results indicated that incorpo- rating the dopants into graphene led to an almost linear decrease in Young＇s modulus. Monotonic reductions in ultimate strength, ultimate strain and energy absorption were also observed. Such doping effects were found to be most significant for silicon, less pronounced for boron, and small or negligible for nitrogen. The outputs provide an important guidance for the development and optimization of novel nanoscale devices, and facilitate the development of graphene-based M/NEMS.

Skull ethnic classification by combining skull auxiliary image with deep learning

Background:China is a multi-ethnic country.It is of great significance for the skull identification to realize the skull ethnic classification through computers,which can promote the development of forensic anthropology and accelerate the exploration of national development.Methods:In this paper,the 3D skull model is transformed into 2D auxiliary image including curvature,depth and elevation information,and then the deep learning method of the 2D auxiliary image is used for ethnic classification.We construct a convolution neural network structure inspired by VGGNet16 which has achieved excellent performance on image classification.In order to optimize the network,Adam algorithm is adopted to avoid falling into local minimum,and to ensure the stability of the algorithm with regularization terms.Results:Experiments on 400 skull models have been conducted for ethnic classification by our method.We set different learning rates to compare the performance of the model,the highest accuracy of ethnic classification is 98.75%,which have better performance than other five classical neural network structures.Conclusions:Deep learning based on skull auxiliary image for skull ethnic classification is an automatic and effective method with great application significance.

Experimental investigation of light storage of diffraction-free and quasi-diffraction-free beams in hot atomic gas cell

In this article we report on the experimental investigation of light storage for several types of diffractionfree beams(Bessel and Airy beams)and quasi-diffraction-free beams by utilizing electromagnetically induced transparency(EIT)technique in a hot atomic gas cell.The experimental results show that the diffraction-free and quasi-diffraction-free beams have better storage performances when compared with ordinary images possessing similar spatial profiles.Meanwhile,the Bessel beams and the quasidiffraction-free images are able to maintain their spatial profiles with a long storage time while the sidelobes of the Airy beam are gradually depleted with the increment of the storage time.We quantitatively analyze the storage results and give physical explanations behind these phenomena.Furthermore,the self-healing of the retrieved diffraction-free beams is verified,signifying that their characteristics preserve well after storage.

Efficient generation of non-classical photon pairs in a hot atomic ensemble

We demonstrate the generation of non-classical photon pairs in a warm S-Rb atomic vapor （＇ell with no buffer gas or polarization preserving coatings via spontaneous four-wave mixing. We obtain the photon pairs with a 1/e correlation time of 40 ns and the violation of Cauchy-Sehwartz inequality by a factor of 23 - 3. This provides a convenient and efficient method to generate photon pair sources based on an atomic ensemble.