定西市耕地利用变化及其驱动因素分析

耕地是保障国家粮食安全和经济发展的基石。文中利用GIS栅格分析及数据分析工具,运用耕地利用动态度、土地利用转移矩阵及因子分析方法,分析了定西市2000-2020年耕地利用变化情况及其驱动因素。结果表明:2000-2020年耕地面积下降了71074.71公顷,2000-2005年、2005-2010年、2010-2015年、2015-2020年耕地利用动态度分别为0.8%、0.67%、0.1%、0.41%,耕地总体呈流出趋势,主要流向林地、草地和建设用地。选取社会经济方面14个因子作为影响耕地变化的驱动因子,经过综合分析发现,影响定西市耕地利用变化的驱动因素主要是人口与经济发展水平,农业科技,工业发展水平,种植业发展水平,且对耕地利用变化的影响逐渐增强。

Specific Regulation of m^(6)A by SRSF7 Promotes the Progression of Glioblastoma

Serine/arginine-rich splicing factor 7(SRSF7),a known splicing factor,has been revealed to play oncogenic roles in multiple cancers.However,the mechanisms underlying its oncogenic roles have not been well addressed.Here,based on N6-methyladenosine(m^(6)A)co-methylation network analysis across diverse cell lines,we find that the gene expression of SRSF7 is positively correlated with glioblastoma(GBM)cell-specific m^(6)A methylation.We then indicate that SRSF7 is a novel m^(6)A regulator,which specifically facilitates the m^(6)A methylation near its binding sites on the mRNAs involved in cell proliferation and migration,through recruiting the methyltransferase complex.Moreover,SRSF7 promotes the proliferation and migration of GBM cells largely dependent on the presence of the m^(6)A methyltransferase.The two m^(6)A sites on the mRNA for PDZ-binding kinase(PBK)are regulated by SRSF7 and partially mediate the effects of SRSF7 in GBM cells through recognition by insulin-like growth factor 2 mRNA-binding protein 2(IGF2BP2).Together,our discovery reveals a novel role of SRSF7 in regulating m^(6)A and validates the presence and functional importance of temporal-and spatial-specific regulation of m^(6)A mediated by RNA-binding proteins(RBPs).

Dynamic Landscapes of tRNA Transcriptomes and Translatomes in Diverse Mouse Tissues

Although the function of tRNAs in the translational process is well established,it remains controversial whether tRNA abundance is tightly associated with translational efficiency(TE)in mammals.Moreover,how critically the expression of tRNAs contributes to the establishment of tissue-specific proteomes in mammals has not been well addressed.Here,we measured both tRNA expression using demethylase-tRNA sequencing(DM-tRNA-seq)and TE of mRNAs using ribosome-tagging sequencing(RiboTag-seq)in the brain,heart,and testis of mice.Remarkable variation in the expression of tRNA isodecoders was observed among different tissues.When the statistical effect of isodecoder-grouping on reducing variations is considered through permutating the anticodons,we observed an expected reduction in the variation of anticodon expression across all samples,an unexpected smaller variation of anticodon usage bias,and an unexpected larger variation of tRNA isotype expression at amino acid level.Regardless of whether or not they share the same anticodons,the isodecoders encoding the same amino acids are co-expressed across different tissues.Based on the expression of tRNAs and the TE of mRNAs,we find that the tRNA adaptation index(tAI)and TE are significantly correlated in the same tissues but not between tissues;and tRNA expression and the amino acid composition of translating peptides are positively correlated in the same tissues but not between tissues.We therefore hypothesize that the tissue-specific expression of tRNAs might be due to post-transcriptional mechanisms.This study provides a resource for tRNA and translation studies,as well as novel insights into the dynamics of tRNAs and their roles in translational regulation.

Sedimentary characteristics of lacustrine deep-water gravity flow in the third member of Paleogene Shahejie Formation in Dongying Sag,Bohai Bay Basin,China

Many types of sedimentary systems occur in the middle of the third member of the Shahejie Formation(E_(2)S_(3)^(2))of the Paleogene in the Dongying Sag east of the Bohai Bay Basin.Due to the topography and material supply,traction and gravity flow depositions are intertwined in this area,and the sand body types are complex and diverse,making it challenging to improve the accuracy of their description and prediction and restricting oil reservoir exploration and development.Therefore,this paper documents our systematic study of the sedimentary characteristics of the southern slope of Dongying Depression,the formation mechanism of different sand body types,and the prediction of sand body distribution.First,according to the coring well’s single-well facies and vertical rock sequence,nine single lithofacies types and five lithofacies association types were identified.Combined with the well logging facies marks of all wells,the depositional models of delta and gravity flow depositional systems were established in the study area.Then,the gravity flow was divided into slip,collapse,debris flow,and turbidity flow according to its development mechanism.Finally,the distribution law of the gravity flow sedimentary facies type was predicted.Gravity flow sliding deposits are primarily distributed near the delta front,slump and clastic flow deposits are distributed near the far slope,and turbidity current deposits are distributed at the far slope.With the gradual shrinkage of the water body in the north-west direction and the continuous advancement of the river delta,the gravity flow sand body gradually disappears in the late E_(2)S_(3)^(2) and transits to delta plain deposition.

Influence of sedimentation and diagenesis on reservoir physical properties:a case study of the Funing Formation,Subei Basin,eastern China

The sandstone of the third member of the Funing Formation(E1f3)in the northern slope zone of the Gaoyou Sag has the typical characteristics of high porosity and ultralow permeability,which makes it difficult for oil to flow.In this study,the lithological characteristics,sedimentary facies,diagenetic characteristics,pore struc-ture,and seepage ability of this sandstone are characterized in detail.Correlation analysis is used to reveal the reason for the sandstone high porosity-low permeability phenom-enon in the study area.The results indicate that this phenomenon is controlled mainly by the following three factors:1)the sedimentary environment is the initial affecting factor,whereby the deposition of a large number of fine-grained materials reduces the primary pores of sandstone.2)The Funing Formation has undergone strong compaction and cementation,which have led to the removal of most of the primary pores and a reduction in size of the throat channels.3)Owing to fluid activity during the later stage of diagenesis,sandstone underwent intense dissolution and a large number of particles(feldspar and lithic debris)formed many dissolution pores(accounting for nearly 60%of the total pore space).Among these factors,dissolution has contributed the most to the development of high porosity-low permeability phenomenon.This is mainly attributed to the inhomogeneous dissolution process,whereby the degree of particle dissolution(e.g.feldspar)exceeds that of cementing minerals(clay and carbonate minerals).The secondary dissolution pores have increased the porosity of sandstone in the study area;however,the pore connectivity(permeability)has not been significantly improved,thus resulting in the special high porosity-low permeability characteristics of this sandstone.

Three-dimensional knotting of W_(17)O_(47)@PEDOT:PSS nanowires enables high-performance flexible cathode for dual-functional electrochromic and electrochemical device

An efficient integration of electrochromic and electrochemical devices into one flexible entity enables both energy storage and energy-saving dual-functionalities.For this purpose,achieving both high electrochromic and electrochemical performance is the key aspect.Herein,a new 3D architecture is successfully made by knotting W_(17)O_(47)@PEDOT(poly(3,4-ethylenedioxythiophene)):PSS(poly(styrenesulfonate))nanowires with NaWO_(3)nanoknots,and interestingly,the 3D W_(17)O_(47)/(NaWO_(3)-knots)@PEDOT:PSS cathode thus-made simultaneously exhibits a large optical modulation(79.7%at 633 nm),an ultra-long cycling life(76%of original optical modulation retained after 12400 cycles),and a high areal capacitance(55.1 mF cm^(-2)at 0.1 mA cm^(-2)).Our density functional theory(DFT)calculations demonstrate that the much improved dual-functional performance is correlated to the raised electronic conductivity and ion adsorption at the W_(17)O_(47)/(NaWO_(3)nanoknots)interface,together with the ion adsorption of PEDOT:PSS in the 3D-knotted architecture.As a proof-of-concept application,different-sized flexible dual-functional electrochromic/electrochemical devices(FDEDs)were assembled and investigated for various application scenarios,including a smart window(15 cm×10 cm),a wearable wristband(20 cm×2.5 cm),and a smart eyeglass.The smart window made of the FDED enables a large temperature difference of 27.6℃ confirm-tested in model houses,where the energy source also powers three light-emitting diodes(LEDs).The understandings of the key governing principles in the electrodes and dual-functionalities provide a timely foundation for the new generation flexible multifunctional devices.